EE Dec 1916 .Pdf

DECEMBER., 1916 15 CENTS

ff, POPULAR NEWS

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Yoa benefit by ineutoiting "7 he Electrical L.rperiwentrr'' when 'citing to advert is , ; The i9xp©1 m ° 233 c Fulton Street, New York Published by Experimenter Publishing Company, Inc. (H. Gernsback, President; S. Gemaback, Treasurer; M. Hymes, Secretary), 233 Fulton Street, New York Vol. IV Whole No. 44 CONTENTS FOR DECEMBER, 1916 No. 8 EYES AND EARS FOR THE SUB -SEA FIGHTERS HOW THE "WIRELESS -WIZ" TURNED EVANGELIST By Thomas W. Benson. 549 A Xmas Story by Thomas W. Benson. 564 A GIANT ELECTRIC TORPEDO THAT EATS THRU THE UPS AND DOWNS OF A TELFZRAPH LINE ... By Thomas Reed 566 EARTH 551 THE MARVELS OF MODERN PHYSICS -COLD LIGHT THE DELINEATION OF INTERNAL ORGANS BY A NEW By Rogers D. Rusk, B.Sc. 567 ELECTRICAL METHOD 552 THE ARLINGTON RADIO STATION-(NAA) AN ELECTRICAL SUBMARINE CAMERA FOR DEEP -SEA By Capt. W. H. G. Bullard, U.S.N. 570 PHOTOGRAPHY 554 THE REVOLVING MIRROR FOR DETERMINING SPARK WHY A MERE SPECK OF RADIUM COSTS $5,000 555 CHARACTERISTICS By Samuel Cohen 572 TRANSMITTING YOUR PHOTO OVER A WIRE By Jacques Boyer 557 ANENT THE AUDION -AN EXCLUSIVE ARTICLE DR. LEE DE FOREST-THIS MONTH'S SUPPLEMENT 561 By Dr. Lee de Forest 574

JLNJLJI1JIJIIl'1J+-+-+-wJ+.--+\.-+.+`.-+.+\.-+.+`:+-+.-+-+\.F.-+.+\s*-+ +-w+. tJJiJ+\.-+.J+.-+l.w+\.-+.+.-f-- .--i.-+."\.-s`J+\.--+`.-J+.+`.-*-+'.LJLJLJ 1+1 ll [114$ L!!J U-53 L» ENE, TEKEL, UPHARSIN ! Thou art if an international crisis impends, it would be a simple LN-1 weighed in the balances and art found matter to station a few huncred submarines in close wanting. proximity to our shores near the points where our LMJ Thus read the fiery handwriting on the battleships congregate, say at Newport News or at palace wall while Belshazzar was feasting Narragansett Bay or any other important point. and debauching. The last Babylonian king was warned At a given moment it would be easy for the enemy L!J but like many others of his predecessors and many of to approach our vessels at dawn and sink our entire his successors, he scorned the warning. His Kingdom fleet, or at least cripple it so seriously that we could not L!-1 had waxed rich and was bulging with treasures. But effectively prevent a landing. That would be the be- history all down thru the ages teaches us that when ginning of the end! nations have too many treasures and when they enjoy Let our pacifists who :,toff at this idea reflect on just too much prosperity, they grow less and less aggressive what' occurred when the Ger :nan war submarine -the as well as less vigilant. As a rule the less fortunate U- 53- suddenly bobbed up it the micst of our At- L!J nations are attracted by the riches of the treasure- lantic Fleet but a few weeks ago. No one knew whence nation, and one nice morning the latter is fallen upon it came and when it was to arrive. Does it not send R-1) and divided or else exterminated by the others. chills down our pacifists' backs if they contemplate The United States today is in no different position that a dozen such submarines could have bobbed up than was Babylonia under Belshazzar's reign. Like his just as readily -and with disastrous results -when we country, the United States is probably the greatest were in rather delicate relations with Germany not so treasure land of the times. But we are inclined to many moons ago? think that Babylonia was far better prepared to meet And would it not be an equally simple matter today the onrushing hordes than we are today. Like the for enemy submarines to enter nearly all our harbors Babylonians, we have grown fat and rich and our and dockyards unknown to us? And how about Panama vigilance has grown less and less as we have grown and Colon? Would it not be comparatively easy for fatter and richer. Our army is spoken of in contempt an enemy U -Boat to effectively block the Canal by by the great nations of the world, and if anything sinking ships at either entrance? Given certain cir- L! -I serious should happen to our navy-now but the fourth cumstances, with the canal made impassable for our in size and power -a seasoned army of 300,000 men fleet, even for 48 hours, the consequences might prove IJ of any first -class power, landed on our shores, would disastrous for us. conquer us in short order. So we are told by military Will we learn our lesson? Will we construct ade- L!J experts, and there can be no doubt as to the logic of quate defenses? At the present writing Canada already L!J that statement if we but take our lesson from what has has taken due precautions. Thus Halifax for instance LNJ happened in Europe during the past two years. has protected its harbor by gigantic, su-lken steel nets, is L!J Fortunately, our geographical position with large suspended from floats. This perhaps a fairly good measure to be taken in war times ; it however does not wastes of water on both sides of our country tends lend itself well for a nation during peace !kJ to protect us in a certain manner, or rather did tend times. protect us until the invention of the submarine. There are subtler and better means. As usual, elec- L! to tricity provides the means. We have a much better . But since it has been shown how ridiculously simple tell -tale if a submarine is approaching than steel nets. it is to send naval submarines across the ocean, our A few dozen Hughes -balances- extraordinarily sen- 0+J former splendid isolation has past into history for sitive to approaching metal masses -can be sunk out all time. In the next war in which we will be in- of sight across the harbor entrance. At a central sta- volved -and no one doubts but that our turn will come tion every vessel can be detected instantly that passes next -submarines will play an even more conspicuous over the line of these Hughes- balances. An observer rôle than in the present war. That the great nations who knows what vessels dó or do not pass over the of the world will build entire submarine flotillas, far line will immediately detect an approaching submar- larger and better than the present ones, is an absolute ine. A siren will announce the fact instantly to our certainty. The submarine has proven its worth, and vessels. No surprise attack will thus be possible. It while it may not decide wars, it certainly can raise is, sad to relate, very possible and feasible today. We tremendous havoc among an enemy. invite our Naval Advisory Board to look into the Moreover, nations do not declare war as leisurely merits of our suggestion. as was the fashion in the past. They aim to strike a The U -53 is our symbolic handwriting on the wall. vital blow first and declare war afterwards. The argu- Will we heed it? ment comes after the declaration, not before. Thus H. GERNSBACK. L!J L1JLll1JIJI.t.J+.+.+\.+\.+. +'+\.J+.J+.+.+.J'+\.+. JLIJ _1,1L1491,11+11+11n1+JIJLJI!M111+3/410 THE ELECTRICAL EXPERIMENTER is published on the 15th of each has been included. ALL accepted contributions a-e paid for on publication. A month at 233 Fulton Street, New York. There are 12 numbers per year. Sub- special rate is paid for novel experiments; good photographs accompanx?ag them scription price is $1.50 a year in U. S. and possessions. Canada and foreign countries, are highly desirable. $2.00 a year. U. S. coin as well as U. S. stamps accepted (no foreign coins or stamps). Single copies, 15 cents each. A sample copy will be sent gratis on request. Checks THE ELECTRICAL EXPERIMENTER. Monthly. Entered as second - and money ordere should be drawn to order of THE EXPERIMENTER PUB- class matter at the New York Post Office, under Act of Congress of March 3, 1879. LISHING CO., INC. If you change your address notify us promptly, in order Title registered U. S. Patent Office. Copyright, 1916, by E. P. Co., Inc., New that copies are not miscarried or lost. A green wrapper indicates expiration. York. The contents of this magazine are copyrighted and must not be No copies sent after expiration. reproduced without giving full creek to the publication. AU communications and contributions to this journal should be addressed THE ELECTRICAL EXPERIMENTER is for sale at all news stands in the to: Editor, THE ELECTRICAL EXPERIMENTER, 233 Fulton Street, New United States and Canada; also at Brentano's, 37 Avenue de l'Opera, Paris. West- York. Unaccepted contributions cannot be returned unless full return postage ern Advertising Office, 58 E. Washington St., Chicago, Ill. 547 548 THE ELECTRICAL EXPERIMENTER December, 1916

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H. G ER N 5 B ACK EDITDR H. W. SECUR A5517C11aTE EDITOR

Vol. IV. Whole No. 44 DECEMBER, 1916 Number 8 Eyes and Ears for the Sub -Sea Fighters By Thomas W. Benson APTAIN KRONIG gazed with A reply in the affirmative started the ma- had read to report at Kiel and report they rapturous eyés at the highly pol- chinery of discipline into action and a half would, despite any ruler of the waves. ished mechanism fastened to the hour later the slim, cigar- shaped hull was Captain Kronig was taking his position steel walls of his undersea craft. gliding smoothly towards the open sea. with the sextant and just as he had lined The U -104 was the youngest model sub- up the reflections on his screen he noticed It had taken over a year of pa- larger tient, scientific endeavor to evolve that ap- marine built for the German Navy and . a spot on the zorizon that grew paratus and across his face there, flitted incorporated the latest and most wonder- each second. brain-kinder of some of the Vater- "Batten down the hatches!" he fumed, for an instant the memory of the epochal ful he day when he had gained permission to inland's cleverest and ablest engineers. It as he dashed to the conning tower while stall it on his beloved ship. was, among other things, equipt with the threw his signal handle to the warning "Eyes and ears," he whispered -"elec- new electrical eyes and ears that enabled the positior and spin the wheel of his perr-

Locate Nets, Mines and Other Submerged A New Electrical Scheme Intended for Use on "Submarines" Whereby These Wonderful Craft May Accurately lias the Ring Metallic Obstructions. It Utilizes the Reflection of Sound Waves and the Hughes' Induction Balance in an Original Manner which of Plausibility. trical eyes and ears for my pet; no longer commander to feel his way safely among scope. Three snort minutes later and the must we crawl along in the dark towards mines and nets. When it had been built tiny electric globes are glowing in the dark- a hidden death." matters not; suffice it to say it was an im- ened steel chamber and the waves are His reveries were interrupted by the portant arm of the powerful undersea navy splashing against the port-holes- of the of the Central Powers. conning tower. chief engineer who entered the control re- room of the U -104 with an order in his Later we find the U -104 off the west The spot had now grown until it hand. coast of Europe traveling northward with vealed the shape of a fast patrol scout, open and the sea quite serene, ex- bearing down on them at the rate of 45 Captain Kronig glanced at the paper and hatches got sighed a thankful "At last" He then cept for a black smudge on the eastern miles an hour and as Captain Kronig horizon that indicated a tramp merchant- it lined up with the periscope a puff of turned abruptly to his engineer, inquiring bow and curtly if everything was ship- shape. man. But the game was bigger ; the orders white smoke appeared over its 550 THE ELECTRICAL EXPERIMENTER December, 1916

SWITCHBOARD FOUND IN tary affairs they have taken sufficient time the missiles very close to the mark in most ZEPPELIN WRECK IN ENGLAND. in which to develop a specially accurate instances; or at least where there is not In a recent Zeppelin raid on England, means for waging aerial warfare from too much fog or intervening mist, which, the defending anti -aircraft gunners were their giant fortresses of the air. The of ' course, makes it very difficult to sight lucky enough to "bag" one of these huge switchboard shown contains twenty -five the various points on the earth or sea with fighting demons of the air. As is gener- levers, each one of which will dispatch accuracy. ally known, electricity plays an important a large bomb earthward, with its several The bombs are supported in a light cra- part in the maneuvering and general opera- hundred pounds of high explosive. The dle -like structure and when one of the tion of all Zeppelin switches on the control war- craft. rfftti- board here shown In the accompanying is closed, a quick -act- illustrations the switch- Here Is What Is Left of the Electrical Control Gear of a ing magnetic Once Mighty Zeppelin, Brought Down Recently in clutch board used for bomb England, Near Harrowgate. Each One of the Twenty - releases the aerial pro- dropping is p 1 a i n- five Switch Levers on the Panel Shown Release a Death - jectile and it speeds ly visible, together with dealing Bomb by Means of a Magnetic Clutch. earthward with rapidly one of the magnetos increasing velocity -in used to furnish current fact, if it is dropt for the ignition of the from a height of sev- gasoline and air eral hundred feet, it charges in the gasoline will have attained such engines which propel a momentum and high the Zeppelin. Several velocity that if it other important parts should strike a building of the control gear will it will . not only ex- be noted in the illus- plode, but will, in many tration, including the instances demolish the steering wheel and a structure and pass signal lever projecting clean thru it from attic from its center post, to cellar. Some of this apparatus being these bombs have pene- visible at the extreme trated so deeply into left of the picture. the earth that they The magneto is directly have never been found. at the left of t h e The Zeppelin a n d switchboard. other aircraft of an al- Some idea of the ter - lied nature as is now rific concussion taking in use, has added a place when one of these fighting monsters' bombs are dropt from various points new phase to the warfare as waged by of the sky is brought to earth may be along the basket suspended beneath the man. With these machines the great wars gleaned from the picture. Zeppelin gas bags, and by means of. accur- of the past, such as our own Civil War While the Teutons are extremely busy at ate sighting instruments the officers in and the Spanish -American War, would this time in their everyday pursuit of mili- charge of the bomb dropping can dispatch have had a much different aspect.

a shell skimmed dangerously near. An- would occasionally reach over and throw "Ready !" was signaled his stern tube; other and yet another followed in quick a switch or adjust a graduated handle. It Full Speed glowed the engine room in- succession just as the undersea craft obeyed was becoming monotonous, in fact weari- dicator, and as the first shot rang out from the diving rudders and slipped beneath the some, this crawling along at half -speed, the cruiser the U -104 dove. "Fire !" was waves. this eternal handling of switches. So, flashed to the man behind the stern tube Down, down, until the submerged depth eventually he relaxed a little as his and like an automaton he pulled the lever dial before the navigator indicated 45 feet. thoughts wandered to a little cottage in that shot the tiny engine of death towards Consulting the chart and the gyroscopic the quaint valley of Genderen. the big craft. Just as the diving rudders compass index the course was laid through And with a supprest "Ach ! Mein flattened out at 40 feet, a heavy shock the English Channel -through that veri- Gott !" his hand flashed to the switch- was felt and the air of tenseness that had table sea of nets and mines; but a glance board and as the wheel spun violently un- settled over the crew disappeared in an at the marvelous, nay, almost supernat- der his mighty thrust, the hand of the in- unanimous smile. Another Britisher sunk ural, mechanism on the wall seemed to dicator lever was thrown to full reverse, by a daring submarine, the papers would convey a feeling of safety to all of this mingled with the sibilant hiss of air. A print the next morning. Meanwhile, the heroic crew who braved any danger for shock, as the mighty machine endeavored marauder crept north at half- speed. the Kaiser and their Vaterland. Deutsch- to check itself, the groans of powerful mo- Detecting and avoiding mines and nets tors as they took up the load, only served land under the Allies ! -that was their bat- was a continual experience. Being in the tle -cry. to tense the men the more as they stood at heart of the enemy's stronghold, it was their posts, ready to obey any order They were rapidly nearing the forbidden their necessary at times to creep beneath a huge doughty chief might give. ship of the first line; exchanging shots with ground, or rather scout, when Captain Kronig snapped that little lever on the Kronig turned to his ever- faithful switch- a scout from the forward turret was an switchboard again and again, watching in- everyday occurrence. board and rapidly manipulated several tently the fast revolving finger on the dial. switches. He clapped on a pair of head Thus they journeyed northward and east, Then, slowly turning a knob, he glanced last scientifically mined en- 'phones and seizing a tiny projecting lever a second dial, and his lips moved, fram- reaching at the turned it down for a moment, then re- it trance to Kiel, the long-ought haven of ing an unspoken hate! safely wormed their way leased it, watching- intently the while a He had detected an enemy battleship and rest, where they large dial just before him. The pointer along the narrow, tortuous channel to se- by maneuvering carefully by means of the curity. sped around quickly and came to rest final- switchboard dials, he had finally succeeded ly at zero. in passing it. A thousand yards beyond, As they glided into their stall alongside "Gut !" he muttered, pulling another lev- according to his log, he signaled for a the rest of the submarine fleet, a mighty er and the peculiar hiss of escaping com- stop and ordering a rise to the surface, he cheer went up for the daring men. Cap- prest air was heard above the whine of stood motionless with his eye glued to the tain Kronig, standing in the conning tower, the-, dynamo and the faint click -clock of a eagle -eyed periscope. heard it, and smiled confidently to his lieu- reciprocating pump. The snap of a switch At first all was black, but slowly, gradu- tenant, who glanced thankfully at the mar- sent home, the adjustment of another han- ally, the light began to appear and there, in velous switchboard below that had made dle and Captain Kronig settled down to the the trough of a wave, he detected a huge such things possible. precise maneuvering necessary to get green hulk. At last he made out the vast * * * * * through to Kiel. hulking form of an armored enemy cruis- With an alert eye on compass and depth er and at the same moment they caught "What scientific device made all this gage, and a steady hand on the wheel, he sight of his periscope. (Continued on page óog) DATE OF ISSUE.-For the information of our readers, we wish to state that the newsstands have the journal on sale between the fifteenth and the eighteenth of the month in the eastern part of the United States and about the twentieth of the month west of the Mississippi River. Our subscribers should be in possession of their copies at these dates. Kindly bear in mind, however, that publications are not handled with the same despatch by the Post Office as a letter. For this reason delays are frequent, therefore kindly be patient and do not send us complaints as to non -arrival of your copy before the twenty -fifth of the month. December, 1916 THE ELECTRICAL EXPERIMENTER 55' A Giant Electric Torpedo That Eats Thru The Earth. AGIANT torpedo that burrows its to bore a tunnel as one bores a pencil earth out to the rear. At the rear are own way through the earth like a through a lump of dough, removing noth- four electro- hydraulic plungers which re- worm and can be exploded under ing, but pressing the yielding earth aside volve intermittently, spreading the ejected any desired spot, has been tested and building up the tube behind the boring matter evenly against the earth already on Staten Island so successfully shield. In this way the Pennsylvania tun- there, and press powerfully against this that the government of one of the Allies nels under the North River were bored. mass, thus forcing the whole apparatus for- now battling against Germany is negotiat- But such a method is useless in earth where ward. ing with the inventor 'for its purchase. there is much rock, gravel, boulder, clay, Within the subterrane are two electric The inventor is Clifford P. Marye, a civil &c. motors of 600 ho:se power each, one of engineer of New York. He calls it the A torpedo to propel itself through the which moves the cutting head and spiral "subterrane," because it may become to earth for any considerable distance must conveyor, while the other actuates the re- land warfare what the submarine is to sea- be able to go straight ahead, no matter volving of the plungers. In addition, there fighting. The idea is not entirely new, says what obstacles it encounters, and it must are four 30 -horse power electric motors the New York World, for it was partially do this without removal of the earth be- which work in concert through four hy- developed many years ago as a possible hind it. In other words, it must eat its draulic pumps and make the rear -end plun- method of tunneling, but was abandoned way through the earth; drawing this into gers behave like hydraulic rams. The because much more expensive than the its interior and passing it out behind, thus whole is operated 3y engineers from a dis- pick and shovel or the hydraulic shield filling up the tunnel as it goes. tance by means of an electric cable wound methods. In modern warfare expense is This is just what the subterrane does. upon a drum in the subterrane and un- no object. The first one that was tried on Staten Is- wound as it progresses. This cable may Many creatures live 'underground and land ate its way through sand and was be as much as five miles long. Through it travel long distances by tunneling their dug out when exhausted. The second one the motors receive their power and the way. The mole, for example, burrows a ate its way into sand, earth and clay, in movements of the several motors are goy-

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Sectional View of the Latest Advance in Military Science -the "Subterrane " -an Electrically Propelled Land Torpedo, and Its Mode of Attack. It . Can Burrow for Miles and When Under the Enemy's Fort, a Press of the Button, and the Fort is No More. route through the earth with his powerful which were boulders, rocks and the roots erned. Specially sensitive microphones are hand- shaped forefeet, and can progress of trees. It has never been possible to supposed to keep the engineers informed underground almost as rapidly as upon the recover it, and it is still somewhere under as to what progress is being made. surface. But the mole digs his way and the hills overlooking the Narrows. Of The explosion chamber is situated to the casts up the earth over him, as every gar- course these two experimental machines rear of the principal motors and is in the dener knows only too well. contained no explosives. form of a ring, the full diameter of the An earthworm progresses through the The Marye land torpedo, here illustrated, subterrane, the spiral conveyor passing ground in a different manner. It chews is a cylinder, forty feet long, eight feet in through its middle. It is large enough to its way along, and passes the earth right diameter, with small rigid steel fins stand- hold 400 cubic feet of any explosive that through its body, only casting, up such as ing upright all over its surface -these to may be employed. it has to remove in making permanent tun- prevent it from being deflected from its The speed at which this war- monster can nels. direct course by obstacles or changes in eat its way through the earth depends on The subterrane is said to be able to bur- the character of the earth. the skill of its engineers, also upon the row its way through the earth almost ex- At the fore -end is a revolving cutting character of the earth -rock, for example, actly as does the earthworm. head the full diameter of the cylinder, necessitating very slow progress. Mr. The greatest difficulty in ordinary tun- working on the principle of a gimlet, with Marye says that from 40 to 100 feet an neling is the disposal of the earth as it is the additional faculty of grinding or tri- hour is the average. This progress consists dug. The longer the tunnel, of course, the turating the earth and stones and draw- of alternate forward movements and paus- greater is this difficulty, as all the earth ing them back into the interior of the ma- es; during the pauses material is accumu- has to be hauled out the full length of the chine. Through the hollow center is a lated anc deposited at the rear. tunnel. Through' soft earth it is possible spiral that turns and passes the "digested" (Continued on page 590) 552 THE ELECTRICAL EXPERIMENTER December, 1916 The Delineation of Internal Organs by A New Electrical Method We have published tlic following article that the result may have been obtained by places, and several advances in medicine appearing in the authoritative `British means quite different, or Medical as yet unexplained and surgery have already been recorded in Journal" exactly as it was rendered in the article in question. the British in this well- known publication. Medical Journal columns. Take, for instance, the following phrase No public statement, however, has any- from the article: "The needle hammer mentioned is connected with a tiny circle to a carbon -like diaphragm of a telephone machine." This certainly does not read as though someone thoroughly acquainted with electricity had written it. Furthermore, we have a lurking suspicion that where a diaphragm is used with a pointed stylus, the results produced thereby are probably caused by means of sound.

Fig. 2. -Brain Picture, from a Case of Gunshot Wound; It Shows Not the Brain Tissue Itself Flg. 5.- Picture of the Liver. This Man Was (which So Far, Has Not Been Found Possible to Wounded in the Axilla. He Was Found to be Delineate) But the Blood Vessels, and a Large Ir- Tender Over the Lower Ribs. The Outline of the regular Patch,Patch Which is the Side of the Lesion. Liver is Shown and in the Middle a Light Patch, (This Picture For Convenience Been Printed Believed to be Pus, Surrounding a Foreign Body. Black on White. In the Original the Vessels Showed White on a Dark Background, and Near the Middle of the Patch Was a Small Dark Mark, where yet been made regarding a piece of which Was Believed to Be a Foreign Body. work of an unusual and somewhat puzzling. character, which has been in progress at It will appear to the reader that quite a one of the casualty clearing stations in good many points are difficult of reconcil- France for several months; though very ing with our present understanding of elec- quietly performed, it has given rise to a tricity, and we are equally certain that host of rumors, surmises, and conflicting many must coarse to the rash conclusion views. that someone has been absent from the edi- The first subject that it brings into mind torial office of the "British Medical Jour- is X -ray photography, and the next is wire- nal" when the article went to press. less telegraphy. It soon, however, becomes Extraordinary as this account of the new apparent that the work, whatever its vaine, discovery is, the reader should bear in mind has no relation to either of these methods. that England at the present time is in the The new work, in fact, appears to suc- grip of war and that reporting from the ceed just where X -ray photography fails, front back to the editorial office is not al- or, rather, it takes up the task of produc- ways an easy matter, particularly when ing pictures of structures hidden far below statements are made from mouth to mouth, the surface of the body just at the point instead of being written as is of course the where X -ray photography ceases to per- case, in times of peace. form it effectively. In other words, the As for ourselves, we think it highly im- new work attempts the delineation not of probable that a picture can be made by dense structures such as bone, but of liv- electrical currents emanating from the ing soft organs, such as the liver, the kid- blood vessels of the brain, or, at least, not neys, and the intestines. by any ordinary or well-known electrical

Fig. 4.- Injured Intestine. This Picture Shows a Portion of the Large Intestine Crossed in Two Directions by a Fold of Small Intestine Believed To Be Lying Behind It. In the Lumen of the Large Intestine is a Light Spot, which Repre- sents a Foreign Body. The Wound By which It Entered the Intestine is Shown by the Oblique White Track Leading Down Towards It. The Correctness of the Picture Was Confirmed on Post Mortem Examination. Take, for instance, Fig. r, showing the injured kidney. That the kidney should practically photograph itself by its own electricity right thru the other tissues, ribs, etc., taxes one's credulity to the utmost. Without, however, wishing to condemn the discovery, if such it is, of James. Shear- er, it will be necessary to await further particulars. We hope to publish during the next few months an exact account of how organs can be seen Fig. 1.- Picture of the Kidney, from a Case of internal by other Gunshot Wound. The Patient Presented Symp- means than with the present X -Ray.- toms Pointing to Injury of the Kidney. The Pic- Editor. Fig. 3.- Picture of the Caecum and Appendix. ture Was Interpreted to Indicate a Wound of the In the Opinion of the Surgical Specialist There Lower Part of the Kidney. Laparotomy Was Was Absolute Correspondence Between the Performed, and the Injured Kidney Removed. THE manner in which the appli- Clinical Diagnosis and the Condition Delineated The Patient Recovered. cation of scientific methods to the in the Picture. In the Appendix may be Seen an Irregular White Mark, Believed to be a Con- medical work of the British Ex- cretion. means as we understand them to -day. peditionary Force in France is en- Of course, the evidence in the pictures couraged and the results obtained That circumstance in itself is sufficient is here, but the reader should not forget have been the subject of remark in various to confer on the work a good deal of at- December, 1916 THE ELECTRICAL EXPERIMENTER 553 traction, but what may be regarded as of still more interest is that it may be con- Electricity Guides Aerial Ferry Over Niagara Falls ceived as utilizing the electricity which is T11E Aerial Bridge here pictured, great that conversation is almost impos- believed to be generated in the body (and the greatest bridge of its kind in sible. to some extent in all living tissues, vege- the world, which crosses the fa- The aero car is run on steel cable lines table as well as animal) as a concomitant mous Niagara Whirlpool at Nia- 1,800 feet in length and is driven by a sev- of the performance of ordinary life proc- gara Falls, is operated by elec- enty -fr+e horse jower electric motor in- esses. tricity. The bridge was opened to the pub- stalled on one cf the banks where are also This new work, therefore, presents so lic for the first time recently. It is run on locatec the cable anchorages built out of many points of interest that, whatever the cable and gives the sightseeing folk a won- concre:e. At first the sensation is a pecu- importance it may hereafter be shown to derful view of the falls and whirlpool. liar one as the car starts on its journey of possess, it is desirable to endeavor to give Along the shore of the rapids on the about one -third mile. The cables swing some account of it despite the facts that right may be seen the gorge trolley route, considerably ar_d altogether the feeling its theoretical basis is not easy to under- which takes the visitors from Niagara Falls created is that of riding in an aeroplane. stand, that it is very far from complete in respect of technical detail, and that the extent of any usefulness it may prove to have in +~ 4 practice cannot yet 4:q; . be defined. 1 What the work seems to do in its present stage is to enable it to be stated, without any manual or other examination, whether the more important vis- we cera of a living patient-such as the liver, the kidneys, 4, the spleen, and the brain -are intact so far as their gross anatomy is concerned, while at the same time it supplies evidence of any departure from the normal in the nature of a considerable enlargement or diminution in size, or an effusion of blood, or the presence of a f or- eign body, or the ex- istence of a tear or cut of the visceral surface. (Upper Left View) -Close View of the These things it Aerial Ferry Cable Car which Crosses the does by providing Famous Niagara Whirlpool at Niagara pictures such as Fells. It Is operated by Powerful Elec. those here shown tr -c Motors Situated on Shore, which (see Figs. 1, 2, 3, 4, Exert a Pull 3n the Traction Cables At- 5). One of these tached to the Car. demonstrates a gunshot wound of the (Lower Left View)-Showing the Sinewy kidney; a second a 1800-Feet Stretch of Cable and the Aero gunshot wound of Car with Its Human Freight Half -way the brain; a third Across the Whirlpool. "It Rides Like an the caecum with in- Aeroplane," Say Those Who Have Made flammatory enlarge- the Journey Thru the Air. ment of the appendix, a fourth a piece of large intestine (Upper Right View) - Another View of torn by a missile the Aerial Car on Its Way with a Merry lodged in its lumen, Party of Sightseers. The Car Has a and a fifth a trau- Capacity of 36 Passengers and matic abscess in the Passes Above the Whirlpool at a interior of the liver. Height of 150 Feet. All these pictures were obtained from living patients, and their accuracy was afterwards proved by to Lewiston then across to the Canadian Aerial railways such as this are much used a successful operation or otherwise. . side and then to Niagara Falls, Ont., Can- abroad and this identical installation was It will be observed that they all present ada. In crossing the whirlpool on the suggested many times before the right man one common feature: the general outline is Aerial Bridge the roar of the falls is so tackles it. The outfit is working admir- exceedingly clear, but no details are vis- ably, the motion of the cab being very ible. The reason for this will be described Lightning completely volatilized 150 feet steady and the velocity has been figured out later on. of wire on the Santa Fe- Cerrillos, Texas, to be just about right for a pleasure trip The Visible Process. telephone line recently, and burned the two of so novel a _nature. Thirty -six passen- The process of producing these pictures poles at the ends of the wire, while three gers can be accommodated. The car is (Continued on page 61o) intermediate poles were left uninjured. 150 feet above the whirlpool. AMONG the hundreds of new devices and appliances published monthly in The Electrical Experimenter, there are several, as a rule, which interest you. Full information on these subjects, as well as the name of the manufacturer, will be gladly furnished to you, free of charge, by addressing our Technical Information Bureau. ;4 THE ELECTRICAL EXPERIMENTER December, 1916 An Electric Submarine Camera for Deep -Sea Photography TESTS have been made during the A device of this kind can be built to oper- or motion pictures, with varying speed, all past summer on board of the ate at any depth of water up to several of which is controlled from above the U.S. ship Vestal with a new de- thousand feet and Mr. Hartman declared water. A sensitive microphone, an elec- vice for deep sea photography that he could photograph the Lusitania, Ti- trical distribution board and the camera are known as an Electric Submarine tanic or other sunken vessels at any time. installed in a special water -tight cylinder Camera. This novel device, which works There is no doubt that this invention above the light projector and may also be automatically under water, promises to open will unveil many unknown depths of deep adjusted or swung into different positions a new and tremendous field for scientific sea life, hydrographic and geological con- and under different angles independent of research -"the bed of the oceans "-because ditions, and it may disclose secrets and the searchlight. it is constructed to be lowered to great wonders of the immense depth of the ocean Another feature of the invention is an depths, 1,000 feet and more, electrically driven propeller and arranged to be con- which causes the whole sub- trolled entirely from above merged device to turn slow- the water. Our front cover ly around its vertical axis, shows the camera in use for so as to take panoramic pic- the purpose of photograph- tures. Thus it is assured ing a sunken ship. that anything within reach This ingenious mechan- of the light and the camera ism may also prove very will be photographed. The valuable to the Navy, as focus of the camera also sunken vessels can be pho- can be automatically altered tographed and their exact or caused continually to position and condition pass through the different shown to experts on a pro- phases, so that in such case jection screen in less hours a certain picture may be re- than it would take divers peatedly taken ar.' while days to ascertain, even if some of those pictures of the same object may be out they . were within reach of of proper focus, others may divers. This may in many appear quite sharp and cases thus help to save the clear. The propeller and lives of the crew of a sunk- the focusing device can be en submarine or other operated or stopped at will ship, and what a boon to from aboard a vessel from Treasure Hunters! which the device is lowered It was at Monte Carlo, into the water. the famous winter resort on At the bottom of the en- the shores of the Mediter- tire device here shown, ranean Sea, that Mr. Hart- The Above Illustration Shows the Marvelous "Electric Submarine Camera" with which is arranged within a man conceived, s e v e r a l Its Powerful Searchlight Suspended Above the Decks of the U. S. Ship "Vestal" strong skeleton steel frame, ago, Just Previous to Being Lowered into the Ocean. Its Inventor Believes He years the idea to con- Photograph that Can there is provided a shock struct a device Such Sunken Wrecks as the "Lusitania" and "Titanic," which Lie in to photo- Several Hundred Feet of Water. absorber ; this is attached graph the unknown depths to another cylinder above, of the ocean, depths which will never be never before dreamed of. It is of interest which çontains in water -tight cylinder a gy- reached by a diver, and the thought to thus that the Government, realizing the far - roscopic electric motor which tends to neu- uncover the mysteries of the bottom of the reaching possibilities of this device, has de- tralize any undue vibrations of the appara- sea, to see what no human eye ever saw signated the Vestal, as the ship from which tus. The electric current is supplied from before. the tests .are being made. the vessel by means of a flexible submarine Prince Albert, ruler of Monaco and one The Vestal had been designated by the cable, but the device itself, which weighs of the greatest authorities on deep sea re- Navy department for carrying on tests with more than 1,500 pounds above the water search, offered his help, having spent mil- this novel device under the supervision of and only some 100 pounds submerged, is lions of francs on submarine research work its inventor, Mr. H. Hartman, a civil engi- suspended from a flexible steel wire rope. and having collected every known device neer, of New York. There has never been All the cylinders and other parts are made for this purpose in his magnificent such a powerful light produced under the to withstand a pressure of 500 pounds and "Oceanographic Museum," newly erected in sea before and at night it can be clearly more to the square inch. Approximately a a dominating position, high on the rock of distinguished to a great depth: current of 100 amperes and 110 to 120 volts Monaco. The Prince was enthusiastic over This device works under water abso- is required to operate the light projector the idea placed before him by Mr. Hart- lutely automatically, and is controlled from and the different small motors. To coun- man, and initial experiments were made at above. It consists of a powerful, water- terbalance the loss of energy in passing once, which proved very successful for tight enclosed light projector, filled with through the long cable, about 50 volts more depths to which sunlight than stated above has to penetrated into the water. be added when the de- Mr Hartman needed a yice is operating in great very powerful artificial depths. light, special made lenses DO you ever wonder what the bed of the ocean looks like, or how a Referring to the illus- for his electrically oper- sunken wreck like that of the "Lusitania" or "Titanic" appears? At tration of the electric sub- ated camera, which can any rate these problems have so far baffled solution. For the purpose marine camera here re- take a multitude of pic- of photographing, either in motion or still views, such unusual and ex- produced, the uppermost tures at different angles chamber - contains t h e and in every direction, and tremely valuable scenes, there has been perfected the "Electric Sub- electric motor attached not finding there the ne- marine Camera" described in this article. It is being tested by its in- to the propeller used for cessary facilities to over- ventor, a New York civil engineer, under the auspices of the U.S. Navy orientating the device come these technical diffi- Department, and has given very promising results. about its vertical axis. culties, he left Monte Car- The next lower chamber lo after six months of ex- contains the electrically periments in the Mediter- controlled motion picture ranean and went to Paris, camera and its auxiliary Berlin and London to consult with experts, nitrogen gas under varying pressure, ac- apparatus. The largest cylindrical cham- to take out patents, etc., and finally, after cording to the pressure of the water and ber carries the ultra -powerful searchlight. the outbreak of the war, he returned to having highly concentrated filaments. The The vertical, small -size cylinder at the bot- America. glass lens is protected from the heat by tom houses the motor- gyroscope unit em- Here he carried on further experiments an inner circle of transparent mica, having ployed for stabilizing the outfit. and constructed a machine which is fitted small openings to allow slow circulation with a'1 features required for deep sea of the heated gas. This light projector An electric room heater invented by an photography. can be adjusted at will to different angles. Englishman throws the warmed air directly One can hear the mechanism working by The photographic camera, driven electric- toward the floor by means of a moving means of a telephone from above the water. ally, can take more than 6,000 stationary parabolic mirror. December, 1916 THE ELECTRICAL EXPERIMENTER 555 Why a Mere Speck of Radium Costs $5,000 DID you ever stop to think why trated essence, or the combined radioac- dium is secured, it is only necessary to go it is that a tiny speck of radium, tivity of the entire mass. half the over a few details. The ore is first ground size of a pinhead costs It is hardly twenty years since M. Curie up fine, and then leached $5,000.00. It is because with strong, hot tons of and his wife discovered radium (1898), nitric acid. The product is next washed ore are needed for the production and possibly in the course of years more of a grain in a weaker acid solution, and again of radium, and because many speedy and economical methods of extract- washed processes have to be gone through with hot distilled water. entailing or concentrating radium will be found, When it has been filtered what comes

ACTUAL RADIU I GRAM OF RADIUM SHOWN RESULTAN . REFININ -.,.., 20,000 LBS.O REQUIRES 20':'' 1B5, PITCHBLEN PITCHBLENDE EQUIVALENTI HERE SHOWN GHT TOASMAL MOTOR BOAT

Comparative Illustration Showing Relative Size of a Man, of Radium Shown, Also How This 20,000 Lbs. of Pitchblende Required to Produce Single Bu'k of Pitchblende Equals Gram in Weight that of a Small Motor Boat in Opposite Scale Pan. ing enormous labor, that a milligram of but with all the improvements which have thru the filter is diluted with water, and radium was worth $120 at the latest quo- been made it is still a long, tedious tation. and sodium hydroxid is added, so that radium - extensive process to be sure. barium sulfate results. There is now still In 1910 it was estimated that there further was only one -quarter of treatment and then the sul- a pound of fates are put into iron pans and radium known to exist in all the dried world in the shape in a hct air oven. Refining in which it can be follows, yielding a sulfate free from utilized for medical purposes. A bit impurities. half the size of a pinhead is valued Then this is placed with at $5,000, and from the point of view carbon in of cost of production an electric (or oil) furnace of special it is worth it. design and some of which From the side of efficiency and consume force several hundred kilowatts of electri- the value of radium is incal- cal energy, and the culable, for it is practically inex- sulfide is once haustible more treated with hydrochloric acid, in the giving forth of en- Alpha, Beta and Gamma Rays of Radium, Indicated by Dots, becoming radium- ergy. Strutt has Dashes and Curves Respectively. On the Left barium chlorid, calculated that one Combined, All the Rays from which the piece of thorianite was then the Alpha Rays Stopt by a Thin Strip of Metal, barium chlorid is ex- at least 280 then Alpha and Beta Rays Stopt by Thick Plate of Metal. tracted by (Continued on page million years old, and in all that time 590} this radio -active substance has been giving The United States Bureau of Mines has off its energy. The life of radium is gen- been operating for erally figured 2500 some time near Denver at years, according to in a rich field of radioactive ore, Carnotite. Soddy. Various other Similar methods are used in Europe, tho figures give this val- improvements are being made as quickly ue at anywhere from as possible. 1500 to 3000 years. There are several methods in use but all It is a law of phys- require dealing with tons of ore to Set ics that energy cans minute quantities of radium finally. Some es energy, use first the acid leach *, others use an al- whether kaline it shall be exprest in leach, followed by an acid leach. force, light, heat and then the ore must be fused with ma- or terial which electricity, all of helps to break it up. The latest method utilizes nitric acid, produc- which are inter- ing changeable. a radium -barium sulfate. The real Thè .plant in Paradox problem before the Valley, Colorado, manufacturer, deals with carnotite, in which there is or abundant a large quantity of uranium ox- "Radium" Dial on Watch rather gatherer-for ide. Glows in Dark. he can only concen- To give an idea trate, not make of the many processes -of radium is to get out of a thru which the ore must go before huge mass of radio -active ore the concen- ra- Actual Phot )graph Showing 'Leach. To pass water thru ashes to form Size of 2?,, Milli- lye. grams of Radium, Worth $300.00, in Glass Tube, EXPERIMENTER December, 1916 556 THE ELECTRICAL Guiding Trains By Telephone By W. A. Wolff IF the unforeseen never came to pass into the nearest siding. Obviously, a great patching division. It consists of a metallic upon a railroad, instead of coming to deal of time was lost with this very crude telephone circuit to which certain calling pass nearly every hour of the day system if trains were late -a not uncom- apparatus is connected at the dispatcher's and night -there might be no such mon occurrence. office and an individual selector at each of officer as the train -dispatcher, and no During the year of 1850, a successful ex- the way- stations, in addition to the tele- great need for telephones along the great perimental campaign was carried out on the phone apparatus. The calling apparatus at steel highways of our country. But the Erie, in an effort to telegraph train orders the dispatcher's office is so arranged that emergency, the special, unusual a predetermined number of elec- case, does arise so often in the trical impulses may be sent out handling of trains -our great at will to signal any one of the systems so swarm with limited way- stations. This apparatus flyers, fast freights, extra sec- consists of a key cabinet, placed tions and private specials - within easy reach of the dis- that the guiding of trains to -day patcher, in which there are a is a titanic task, requiring the number of keys, one for each of best of efficient equipment plus the way- stations. These keys brains and steady nerves on the are so designed that the number part of the train -dispatchers and of impulses sent by any one of operators. them will actuate the correspond- Go back to the early days and ing selector at the way- station of course you will find no corn- that is wanted. Therefore, when plexities in the directing of the dispatcher operates a key, trains. Primitive railroading only that station is called, as the was an extremely simple propo- selectors at the other stations sition. are so arranged that they will When the first really success- not respond. The average time ful locomotive, capable of pull- required for the dispatcher to ing cars was started on the Bal- call a station is approximately timore & Ohio lines in 1839, the three seconds. problem of dispatching the train The flexibility of the telephone was simply one of making sure system also makes it possible to secure additional through tele- that the track was clear as far Using Portable Telephone to Report the Delay of His Train. ahead as the engine driver could Conductor graph and telephone circuits be- see. The train started when it tween terminal points or division was ready and reached its destination when to trainmen and conductors from a central headquarters without the expenditure of a it got there. There was no schedule and point, and from that time until the latter single dollar for increasing the outside wire there could be none because of the uncer- part of 1907, practically all train movements plant. This may be accomplished by sim- tain operation of the locomotive mechan- were directed by means of the telegraph. plexing and pharrtoming the train dispatch- ism. The introduction of the telephone into ing circuits. However, when the railroad companies the world of business resulted in its speedy A simple circuit is a telegraph circuit ob- began to run two trains on a single track recognition as an indispensable asset in the tained by connecting repeating coils or re- road at the same time, starting from op- successful economic and efficient conduct of tardation coils to the telephone circuit. posite ends of the line, it became necessary both large and small business undertakings. These coils make it possible to carry on to devise a scheme for keeping the trains There was, however, one essential thing simultaneous telephone and telegraph com- from meeting each other head -on or else lacking, without which the maximum bene- munication over a single pair of wires with- meeting at some point where neither could fits obtainable in a commercial telephone out interference. pass the other. To avoid these things, system could not be secured in connection A phantom circuit is a circuit obtained trains were run on the "time interval" sys- with the handling of train movements. by connecting repeating or retardation coils tem. Old railroaders will remember this This one thing was a means of calling, to two existing metallic telephone circuits as the system under which the ruling train quickly and reliably, any one of a number in such a manner that a third through tele- had the right of one hour against an op- of way- stations located in a dispatching dis- phone c =rcuit is provided over the two pairs posing train of the same class. If the lat- trict or division, without interfering with of wires. In this way, three telephone con- ter did not appear within the hour, the any other station in that district. versations may be carried on at the same

by Telephone. A Message Operator Assisting in Train Dispatching A Switch Tower Out on the Line -Operated from Orders Received by Telephone. The selector was the result. time over the two original circuits. Prac- train left the siding and went on, sending a railroad having message or flagman some distance ahead as fast as his The telephone train dispatching line is tically every nothing more nor less than a party tele- commercial circuits paralleling their train legs could carry him, to flag the opposing lines is utilizing these wires to the two came within sight of phone line extending from the dispatcher's dispatching train. When dis- (Continued on page 59o) each other, one of them had to go back office to the various way -stations on his December, 1916 THE ELECTRICAL EXPERIMENTER 557 Transmitting Your Photo Over a Wire By Jacques Boyer Paris Correspondent of "The Electrical Experimenter" THE possibility of transmitting a sapphire point. This exploring sapphire is reflected from the movable mirror, pass- photograph or drawing over an point is attached to a stylus which is piv- ing through a convergent or double- convex electrical circuit was early recog- oted in front of the revolving transmitting lens, against which is placed a tone screen, nized and even as far back as cylinder around which the relief print is composed of glass strips cemented together, 1855 there were attempts made to stretched. This arrangement is thus ca- each strip being of a different value run- solve this interesting and baffling problem. pable of registering the varying relief hills ning from dead I lack to full transparency Experiments were made in 1855 and later and valleys of the picture and transmit- (i.e., from right ro left). According to notably by l'abbé Caselli (a French priest), ting these faithfully in the form of undu- the zone through which the reflected oscil- by de Meyer in 1869, d'Arlincourt in 1872, lating electric currents over a telephone cir- lograph sight beam projects, the ray is de Cowper and M. Senlecq in 1879, Pro- cuit, etc., in virtue of the fact that one end tinted more or less but no matter on which fessor Korn, of Munich, in 1907 and of of the stylus is joined to a variable resist- part of the tone screen the ray falls, it is late Edouard Belin. The latter investiga- ance device. Each varying tone of the pho- always focussed tack by the convergent tor of the problem spent much time and tograph thus causes to be sent out over the lens on to the same fixed point in front study on the subject and his perfected apparatus for accom plishing the purposes set forth was evolved in 1909. Several illustrations are presented herewith showing the appearance of the Be- lin' transmitting and receiving apparatus, also the highly efficient results obtained in transmitting his like- ness over a copper wire many miles long by a series of rapid electrical impulses. The lower right view shows the corn- plete Belin Télestéréo- g r a p he apparatus; while the upper left view is that showing a close view of the receiving instrument. The reproduced portrait of a lady may be plainly seen on the Upper Left View- Close View of Belin cylindrical drum. The Telephotographic remaining two photos Receiving Appara- are those of M. Belin tus. Note the Por- as received over an trait of a Lady Re- produced by the C electrical circuit. Apparatus on the Primarily the sys- Revolving Cylinder. Upper Right View tem of M. Belin is Portraitof M.Belin,- based upon the princi- I nventor of the Sys- ple involving a revolv- tem Here Describ- ed, as Reproduced ing cylinder at both After Electrical the transmitting and Transmission Over receiving a Long Circuit. stations, Lower Left -An- these cylinders being othsr Picture of M. electrically or other- Belin as Repro- duced by His wise controlled so as Unique Apparatus. to both rotate syn- Lower Right -The chronously or at ex- Complete Telepho- tographic Instru- actly the same rate. ment. The Box at This is essential in Left Houses the Re.. practically a 11 tele- volving Cylinder photographic schemes. and Recorder. The photograph to be transmitted is transferred or copied on line to the receiving machine .a certain of the revolving receptor cylinder. The heavy photo paper and the proof so ob- strength of current. Moreover, the trans- ray of light passes through a minute aper- tained is prepared according to the mitting cylinder gradually moves past the process ture in the wall of the receptor cabinet, of Poitevin, known as the pro - sapphire point, being mounted on a threaded which is a small box forming a dark room cédé "au charbon," which is a photographic shaft. This accounts for the fine lines seen paper made for the cylinder which has a sheet of sen- with gelatine bichromate. in the photos reproduced herewith. The sitized photo paper stretched around it. This has the property of becoming insol- process, however, takes but little time to uble in water when This cylinder moves about its axis and it is exposed to the perform the necessary steps in transmit- also end -wise on a threaded bearing (in light. Once removed from the printing ting and recording a photo. frame it is washed in exact synchronism with the transmitting warm water and the Coming to the receptor apparatus, we cylinder), so that the reproduced picture is gelatine is dissolved more or less, accord - have a Nernst lamp projecting a luminous ing to varying composed, as shown, of light and dark lines, the degrees of opacity of ray onto the tiny mirror of a Blondel os- these being sufficiently close together to the different parts of the negative. Fi- cillograph. The mirror element carries the give a fairly perfect picture. nally there is obtained a proof representing looped current wires of the oscillograph in relief or having raised and sunken por- and which is placed in the powerful mag- tions corresponding exactly to the varying netic field of two electromagnets excited Electrici.y is the only agent which will gradations of tone in the negative. These from a direct current source. Hence the thaw frozen water pipes without digging variations in the physical surface of the movements of the small mirror will be pro- them up. With the action of electricity the prepared photograph are scarcely percept- portional to the intensity of the current pipe can be easily thawed in a short time, ible to the touch but are, nevertheless, of transmitted from the sending machine. the passage of current through the pipe sufficient magnitude to affect a very fine The light ray projected by the Nernst lamp heating it sufficiently to melt the ice. 558 THE ELECTRICAL EXPERIMENTER December, 1916

ELECTRIC TREATMENT FOR DIA- Trolley Car Spreads Yuletide Cheer THERMY OR FROZEN FEET. To most of us the trolley car appears nected up with a special and cleverly de- The severe cold existing at the present the same always, except, perhaps, during signed flasher as it is termed technically, time in the trenches of the European bat- the holiday season when there is usually which causes bands of light to ripple across tlegrounds made it a necessity for the a change in the advertising cards that ar- the flag and to thus give a very realistic various fighting nations to employ some effective means for curing frost -bitten feet of the soldiers. Naturally, a problem of this kind attracted the attention of scientists in various countries and especially those of the warring nations, all of which have developed different means for curing this ail- ment. One of the earliest methods employed was that of placing the feet in hot water in which a given quantity of sodium chloride or common table salt was placed. This proved a partial success, inasmuch as the frost bite was relieved, even though only momentarily, but the need for a more effective cure was realized. .Therefore, the electrical method for this work, which has recently been developed at the Royal Baths, Horrogate, England, promises much relief to patients. The method employed is purely electrical and the photograph herewith illustrates an invalid being cured from the terrible afflic- tion of frost bite by electric means. As far as the constructional details of the apparatus used, there is very little information that can be obtained due to pat- rA Trolley Car that Helped to Spread the Xmas Spirit in Toledo, Ohio. It Was Decorated Very ent reasons. It is thought, . however, that Attractively and the Electric Flag at the Front "Waved" Realistically. faradic electric currents are being employed. rest our attention as we ride along. effect of a flag waving in the breeze. In the accompanying illustration we see These electric flags are now being used The two plates which are bandaged un- how a Toledo, Ohio, trolley car was at- very extensively thruout the country and der the feet of the invalid shown in the il- tractively decorated with an electrically as might be supposed, they are not to lustration are made of asbestos forms on illuminated sign, bearing the message be employed in direct conjunction with any which high resistance wire is wound. This "Merry Xmas -Do It Electrically "; also, advertising matter. is heated rhythmically by the electric cur- a floating electrical flag on the front end of It might seem a very excellent idea for rent obtained from the machine on the the car, the tout ensemble presenting a very the electric companies or even the trolley right. The various knobs as seen on the pleasing as well as effective advertising at- corporations (who wax fatter and richer cover control the intensity of the current traction. each year on the public's hard -earned nick- supplied to the apparatus applied to the The purpose of this novel trolley car els) to carry out such a scheme as this, patient. The meter on the switch -board in- decoration was to help keep alive in the w rich, to say the least, is not prohibitive dicates the amount of current consumed. public mind the numerous meritorious features of doing things the electrical way. During "Electrical Week" to be held this December, electrical contractors and dealers thruout the country will preach the utility and economy of using electric current not only for lighting the home, but for doing the household wash, baking and cooking, washing dishes, ad infinitum, and not forgetting the electric curling iron heater to beautify my ladies' coiffure. The American flag outlined in electric light bulbs and shown on the front of the trolley in the present illustration, is con- KILLING GERMS ELECTRICALLY. A recently past Federal law requires a system of drinking water purification to be used on public carriers. An equipment using ultra violet rays from a mercury vacuum light has proved successful for this work and is being installed on many of the large lake passenger boats. A mercury tube is immersed in a tank or receiver in the water system so that all the water used is at one time or another exposed to the ultra violet rays from the tube. Inasmuch as the mercury tubes require 220 volts, direct current, and the lake boats have but 115 volts available, motor-generator sets must be provided to operate on 115 volts and provide 220 volts for the lamps. The operation is automatic; if the tubes Photo American Press Assoc burn out or the voltage fails, the electric- Recently Perfected Electrical Method of Treating Frozen Feet of European Soldiers. ally controlled intake valve of the tank is closed. from the expense standpoint, besides being WIRELESS STATION AT FORT The Western Electric Company recently one that is bound to spread good cheer CONSTITUTION. furnished six motor -generator sets for use in one way or another, in much the same The Portsmouth, N.H., coast artillery on passenger boats. This is undoubtedly way as the appropriately decorated win- district is now equipped with wireless tele- the first time a motor -generator set has dows in our stores spread the Xmas spirit graph. The station is located at Fort Con- been used to annihilate germs. at Yuletide. stitution. December, 1916 THE ELECTRICAL EXPERIMENTER 559

LORD KELVIN. Sir William Thomson represents a fine KILLING THE TOBACCO BEETLE December Marks His 9th Death example of the scholarly ability to engage WITH X -RAYS. Anniversary. in widely different fields of endeavor. One The tobacco manufacturer of to -day does Born, June 26, 1824. Died Dec. 17, 1907. of his earliest interests was in the subject not fear the damage occasioned by the to- William Thomson, who later became of heat, and here he showed his insatiable bacco worm. This pest has a variable pe- Lord Kelvin, was born in Belfast, Ireland, desire to consider problems from the basic riod of incubation, covering an interval of a on June 26, 1824. At the age of ten he viewpoint of energy. There was no abso- week or two, depending upon the tempera- entered the University of Glasgow, in which his father held the chair of Mathematics. In 1841 he entered Cambridge University, from which he obtained' his Bachelor's degree four years later. After studying a year in Paris under Regnault, the famous physicist, he was recalled by the Univers- ity of Glasgow to take the Chair of Natural Philosophy, a title which included both physics and chemistry. He was knighted in 1866. He retained this post until his death. One of his principal characteristics was brought out in connection with his work on the Mariner's compass. It had been the custom to use large, heavily magnetized needles to actuate the card and correction against the effects of nearby iron, which was a difficult matter. In 1874 Thomson was asked by the editor of a popular monthly to contribute an article on the corn- pass. In preparing this his attention was brought strongly face to face with the de- ficiencies of the instrument then in vogue. And, when five years later a second article on this subject appeared, the author had redesigned the compass. His model, now in universal use, employs a light ring instead of the old card, and a number of small magnets fastened near the point of By Means of This Extremely Powerful X-Ray Outfit It Is Now Possible to Kill the Tobacco Beetle in suspension. Boxed Cigars as They Travel Under the Rays at the Rate of 40,000 Cigars an Hour. In theoretical electricity, Sir William Thomson was the pioneer in the develop- lute scale temperature, and in a perfect ture. Apparently sound cigars would be ment of the theory of the ether. He laid engine the temperature is inversely pro- shipt from the factory only to be con- down the hypothesis that all space is per- portional to the absolute internal tempera- demned, in a short while, by the dealer or meated by a weightless, perfectly elastic ture of the working agent. From this he the latter's custcmers. The unseen eggs medium, thru which are transmitted all deduced the location of the absolute zero, hatched out their worms within the boxed electric and magnetic forces. As opposed with reference to such a point as the tem- cigars and as the insects desire to see the to the former theory of "action at a dis- perature of ice. His values coincide very outer world, they break thru the tobacco tance" this theory gave a means of apply- nearly with other values since determined of the cigar, thus producing a hole by their ing mechanical analogies to electrical wave in many different ways. His interest in journey and consequently injuring the phenomena. Later, other scientists de- geology led him to formulate a theory as product. veloped the equations which relate to all to the age of the earth and to predict the Several means have been tried to exter- forms of wave motion, whether of sound, probable amount of coal which might be minate :hem, suca as by electrocuting the of water, or of electro-magnetic force. available for future generations. eggs and passing high. frequency currents One of Thomson's inventions was the Lord Kelvin's life was strewn with thru the tobacco, thus trying to kill the quadrant electro- meter, an instrument for honors and in 1892 he was made a Peer of newly hatched worms. But these methods the measurement of very high potentials the Realm, with the title of Baron Kelvin. have proven a total failure inasmuch as as generated by electrical machinery. He His own sovereign conferred on him as the beetle was not exterminated from the well a Privy Councellor's degree, the Grand tobacco. Cross of the Victorian order of Merit. This problem has been handled in an en- And above all, his lovable personality tirely different manner by Franklin S. and warm heart brought him an army of Smith, a well -known electrical engineer of friends; and when on December 7, 1907, Philadelphia, Pa. He employs the X -rays the cables carried the news of his death, all in his method of killing the eggs and scientists and those interested in science worms of the tobacco beetle, and has been the world over mourned. surprisingly successful in his task. It has taken some years of research, RAPID ELECTRIC DEVELOPMENT however, to perfect the X -ray sterilizing IN JAPAN. machine as now employed in a number of Electric service in Japan began in 1887 factories in this country-notably at Tam- with a "home- made" 75 lamp dynamo in- pa, Florida, and Harrisburg, Pa. stalled at Nihonbashi. In 1907 a 15,000 - The apparatus herewith shown is the lat- K.W. hydro electric station transmitted est type of machine which has proven par- power to Tokyo, 50 miles distant. At the ticularly efficient. The X -ray tubes are of end of 1914 a 14,000-K.W. hydro electric the Coolidge heated -filament type and are station transmitted power 140 miles at a encased in cast Iead housings and envel- pressure of 115,000 volts. This station oped by oil which fills the casings. The brought the total capacity of all the gener- rays produced by the tubes issue forth thru ating stations in operation in Japan up to a small window glazed with horn fiber, 609.000 K.W. which is specially treated to prevent ab- There are no less than 578 generating sta- sorption of oil. The anodes of the bulbs tions in Japan to -day, owned by nearly the are .& oled by circulating water which is same number of companies. More than 90 fed to them thru very small tubes. The per cent are joint stock companies. The Coolidge tubes are connected to high ten- latest estimate of the available hydraulic sion transformers as seen in the photo. power in is 2,300,000 The boxed cigars are past under the Sir William Thomson, Better Known as Lord Japan H.P. Japan is Kelvin, the Famous English Physicist Who De- becoming an active market for electrical rays by a moving conveyor which travels duced Many of Our Present Electrical Theories. products of every kind. at the rate of nine inches a minute. This is driven by means of an electric motor as also developed the well -known ampere -bal- The government of India will extend its noted in the photo. Altho this machine ance and many other important inventions wireless system until every army post has a seems simple in construction, yet 40,000 which are universally used. station in the charge of a trained officer. cigars are sterilized per hour. 56o THE ELECTRICAL EXPERIMENTER December, 1916

DO YOU KNOW HOW TO TELE- CAN INFLAMMABLE OIL BE AN ELECTRICAL FLOAT MADE PHONE? ELIMINATED FROM ELECTRICAL OF FLOWERS. The majority of us use the telephone sev- APPARATUS? The accompanying illustration shows a eral times a day at least, but do we always Refined petroleum or mineral oil has particularly attractive float recently drawn give the party at the distant end of the line found application in the electrical industry thru the streets of Youngstown, Ohio, in the benefit of the doubt? The Telephone in large quantities, notably in transform- an industrial parade. This gigantic replica Review mentions that a large terra cotta ers and oil switches. The high insulating of an electric motor was formed of flowers manufacturing company, who publish a bul- value of oil combined with its fluidity and appropriately mounted on a wooden skele- letin for their employees, devote an entire suitable values of page in a recent issue to calling attention to freezing p o i n t, the proper method of telephoning. Expe- boiling point and rien^e justifies us in saying that some of our flash point and its fellow- telephonists need to take this lesson lack of volatility to heart. The page is reproduced for their have made it espe- benefit: cially suitable for TELEPHONE such purposes. In "In talking over the addition it serves telephone as a lubricant of face the transmitter the contacts of im- a few inches from the mouthpiece mersed switches. and Mineral oil has speak clearly and distinctly." o n e drawback, Also when you try to signal central (in- however, and that cluding your house switch-board operator) is its inflammabil- to have a call transf erred, move the hook ity, and a number up and down slowly -not rapidly!! If you of destructive fires move it too fast the line signal relay has can be attributed not time to act. to the presence of this material in EVEN THE HORSE HAS AN ELEC- considerable quan- TRIC HEATING PAD. tities in power Even the horse enjoys the luxuries of the houses and sub- electrical current today. If Dobbin is sick stations, says Elec- or has a pain in his, perhaps her, abdominal trical Review edi- [ region the . twentieth century owner of torially. It would seem An Unusual Flower- decorated Float Built to Resemble a Huge Electric Motor, horse-flesh calls not the old time doctor as if there Appeared in a Parade in Youngstown, Ohio. with his hot cloth panacea, but an up -to- ought to be some which date V.D. who applies, instead, an electric material which will combine the desirable ton work. The structure was carried on a heating pad which fits over or around any properties of mineral oil with freedom concealed electric- vehicle body and proved part of the animal's body. from inflammability, but as yet such a sub- to be one of the leading features of the Sick horses are cared for in the elec- stance does not seem to be available. parade. The model was complete even to trical way at the Angell Memorial Hos- That the problem is not one without a the screweye at the top and the pulley on pital for Animals at Boston, Mass., and the hope of solution is indicated by some tests the shaft. This is a good suggestion for horse here shown is being treated by the recently made in Germany. The material electrical contractors all over the country, use of a specially designed heating pad. experimented with was carbon tetrachloride. as many opportunities will arise during The pad, illustrated in service herewith, is This liquid is non -inflammable and non-ex- the coming America's Electrical Week 4 feet long and 3 feet wide; it has three plosive. It has a boiling point of 78 de- when such floats can be advantageously heats and a maximum energy consumption grees centigrade and is decomposed at a used to advertise electric service. of 600 watts. One side is rubber -covered, temperature of about 290 degrees. Its spe- Some years ago an Eastern electrical and it is connected to any convenient re- cific gravity is about 1.6. It is colorless and contractor in a small city evolved a clever has an agreeable idea for an electrical parade float. This aromatic odor. It design made use of an electrical sign of is a good insula- quite large proportions, the low voltage tor and its dielec- bulbs of which were winked on and off tric strength is by a flasher, the current being supplied by not much different the storage cells removed temporarily from from that of min- an electric vehicle. -Photo courtesy Elec- eral oil. While it trical World. is possible to use this substance as a LECTURES ON ELECTRICAL TOP- substitute for oil ICS TO BE GIVEN IN NEW YORK in electrical ap- CITY. paratus, it h a s A number of important courses of free two disadvantages. public lectures on electrical subjects will be One is its volatil- given in New York City during the school ity and the other year, under the direction of the Department is that it acts of Education. chemically upon Dr. Ernest R. Von Nardroff, of Stuyves- copper, rubber and ant High School, will deliver twelve lec- certain other ma- tures on "Electricity, Atoms and the Ether" terials. However, at the American Museum of Natural His-

aluminum, mica tory, . Manhattan, on successive Saturday and fiber do not evenings, which began October seventh. seem to be affected The second of twelve Monday evening lec- by it. To over- tures by W. Wallace Kerr of the Hebrew come its volatility, Technical Institute, on "Principles and Prac- experiments were tices of Electrical Engineering," was given made by covering October ninth, at Public School 62, Manhat- it with a layer of tan. On October tenth Charles L. Harring- glycerine, but this ton began a course of six lectures, given on did not prove en- alternate Tuesday evenings, on "Electric- tirely satisfactory. ity and Magnetism," at Public School 36, the Treating "Old Dobbin" to an Electric Heat Bath by Means of an Electric Blanket which May Be Wrapt Snugly About Any Part of the Body. The German in- Bronx. vestigator, Mr. M. In Brooklyn, Frederick W. Huntington, of ceptacle about the premises by a 25 -foot Vogelsang, suggested that a mixture of oil Erasmus Hall High School, started a course flexible cord. Dr. F. H. Rowley, president and carbon tetrachloride, which would of lectures on "Electricity and Magnetism," of the Massachusetts Society for the Pre- combine somewhat the properties of the at Public School 159, on October sixteenth vention of Cruelty to Animals, first used two. might be useful. A mixture of three and which will be given on successive al- the pad in cases of "black water," a disease parts of the former with one of the latter ternate Mondays. On alternate Mondays horses are subject to when overfed and is not very inflammable and volatilizes he will repeat the lecture in Queens, at Pub- under -exercised. very slowly, so that it might prove useful. lic School 34. December, 1916 THE ELECTRICAL EXPERIMENTER 561

METAL DOME Dr. Lee De Forest-This Month's Supplement CATCHES RADIO TIME SIGNALS. By George V. Tudhope R LEE DE FOREST, the well-known graduate work, specializing in mathematics THE great telescope which was on ex- radio engineer and scientist, who is and physics, he received the degree of hibition in the Liberal Arts Building D possibly best known to our readers Doctor of Philosophy. For his Doctor's at the Panama- Pacific International and others through his research work in de- thesis he prepared a paper entitled "The Expos:ition has been installed in the City veloping the Audion detector and amplifier, Reflection of Hertzian Waves at the End of Oakla id's new observatory and is to be is a man of mature years and gives one of Parallel Wires," which was received used, primarily, as a branch of the city's the impression of being a profound think- very favorably and with considerable com- school work. . er; and those who know him well can veri- mendation by his professors and fellow This telescope is the eighth in size and fy this fact. It is said of him that even students. the fifth in power in the United States, and when eating his meals he is inclined to After leaving the University he engaged is the largest known to have been erected constantly scheme out some new wireless with the Western Electric Company, at by any municipality for public school pur- circuit or calculation which has been up- Chicago, in their experimental telephone poses. It is twenty -eight feet in length, permost in his mind. He is a rapid thinker laboratory. In 1900 he began active work weighs ten tons and carries a Jena glass ob- and personifies great dynamic energy. A in wireless telegraphy, first in Milwaukee, jective lens, twenty inches in diameter. slide -rule and notebook are his constant then at the Armour Institute of Technol- When the telescope is pointed toward the companions and he trusts no intricate cal- ogy, in Chicago, where he began to de- zenith, the object glass or upper end of the culations or philosophical problems to his velop the first form of electrolytic wireless tube is thirty -eight feet above the floor. The assistants, but always makes his own de- detector. In 1901 he came to New York observatory is located on one of the foot- ductions. with this receiver to undertake the report- hills of the Coast Range in California. Dr. de Forest's general bearing and ap- ing of the International Yacht Race of that In order to facilitate the technical work pearance is that of the born scientist; in summer off Sandy Hook. During this work of determining the exact latitude and longi- fact, one could hardly picture this inde- the Ruhmkorff spark coil was used as a tude of the observatory, which must be fatigable worker in any other rôle. Like transmitter, . but its many disadvantages known as a base for all future observations most great men he does not narrow him- prompted Dr. de Forest to design an al- the author was requested to provide radio self down to the point where his philo- ternating current transmitter. He never apparatus sa that the time signals from the sophical studies and researches occupy his used the Ruhmkorff coil after that first United States radio station at Mare Island, mind all of the time. He is broad -minded, trial. The alternating current generator some twenty-five miles distant, could be re- widely read and a great lover of music and transmitter are now universally used ceived and used as an aid in these and and one of his principal researches in in all modern wireless transmitting sets. other observations. later years has' been the development of Dr, de Forest was also the first to use musical Audion bulbs; and he has had a the telephone receiver with an auto- restor- good measure of success with them. ing detector, in place of the relay and So enthusiastic was Dr. de Forest in his Morse ink recorder. This one simplifica- early wireless research days when he first tion has perhaps done more to commercial- came to New York, that he carried on his ize wireless telegraphy than any other sin- first courtship via wireless. At the time, gle factor. this story was one of the most popular in Due to the simplification of transmitter the daily press; and the invention really and receiver which he introduced, the busi- worked very well indeed; so well, in fact, ness of his company, The American de that Dr. de Forest concluded his experi- Forest Wireless Telegraph Company, be- ments in this direction by marrying the gan to increase by leaps and bounds so girl! The modus operandi of engineering that in 1906, there were over fifty vessels this startling experiment involved the in- equipt with the de Forest system and stallation of a powerful wireless transmit- some thirty shore stations. The United ting and receiving station at Dr. de For- States Government at that time pur- est's laboratory, also one at this living chased little except de Forest ap- apartments and a third at the apartment of paratus. his sweetheart. Dr. de Forest designed and in- The month of August in the year 1873, stalled the first five high -power radio saw the birth of Dr. Lee de Forest, in the stations in this country for the then small town of Council Bluffs, Iowa. United States Navy at Key West, His parents at an early date moved to Ala- Pensacola, Guantanamo, Colon and bama, and it was here in the palmy South- Porto Rico. During this period he land that the subject of our supplement applied for, and took out, a large Wireless Time Signals Are Readily Picked Up at This spent his boyhood days. He was educated ti umber of radio apparatus patents, California Observatory by Using the Metal Roof as an in the private schools and late. attended among the most important being Antenna. the Mt. Vernon school for boys in Massa- those covering the horizontal receiv- antenna or lo- The large dome of the observatory is chusetts, at which Academy he prepared ing antenna; the directive made re- for entrance to Yale University., as by this calizer and the duplex method of sending constructed of sheet metal and to time he had quite firmly decided upon a and receiving by means of two separate volve upon an iron track, about forty -five re- feet above the ground by flexible steel cables scientific career. And so as a young man, stations, one for sending and one for floor. we find him at the by a telegraph wire (this driven by an ele:tric motor on the first studiously engaged ceiving, connected Having noted that the dome, motor and Sheffield Scientific School at Yale with the arrangement is used at most of the trans- insulated from degree of "Mechanical Engineer" as his oceanic wireless stations to -day although steel cables were sufficiently goal. Dr. de Forest has never been given credit the ground by the plaster boarded frame He graduated from this institution in for his invention). Also in the Russian - walls and. wooden floors, and not wishing 1896 and after pursuing two years of post- Japanese War the de Forest radio appa- to mar the scenic beauty of the observatory ratus proved extremely valuable. and its surroundings by the erection of a 1111111111111111111111.1 ..l .11111,1,,,,,1111.111.,111,,,,,,,l .,11...,l...... 1,1,1,.,,,. ,,,, ,,,,,,,,,,,, metal dome of the observa- In 1906 he devoted his entire energy to radio mast, the the problem of wireless telephony. His tory was used as the antenna. An ordinary, WITH THE JANUARY ISSUE first invention of importance was the use two -slide tuning coil with silicon detector, small condenser and two thousand ohm we will present another of the microphone in the earth connection, where it has been used in practically all receivers, were connected in the regular way transmitters ever since. to the steel cables leading in from the dome SUPPLEMENT wireless telephone and to a one -inch galvanized iron pipe driv- He developed the water jet arc which has with of a famous electrical inventor. This subsequently been featured by the Italian, en about eight feet into the ground, the a series promised to the result that the radio time signals came is third of Maj orana. to be our readers. Most important of all the de Forest in- in sufficiently clear and loud enough These supplements are printed on heard two feet from the receiver. ventions is, of course, the Audion group. Charles Burckhalter, Director fine art paper, ready for framing. Beginning to work on the principle of a Professor They are invaluable to adorn your of the Observatory, is an ardent advocate heated gas detector in 1900, he demon- of radio receiving sets as permanent fixtures den, your wireless station, or your strated the practicability of this type. Co- laboratory. Flem- in all places where astronomical observa- incidently with the description of the tions are made. Order your Copy now, to make ing valve Dr. de Forest brought out the sure you will get it. first Audion element mounted in a vacuum An electric oven in Toronto, Canada, a.11111111111111111111111111111111..1M..UM..11111111111111111111111111.1111.11.11 11.111.111.11111111111111111a (Continued on page osi) turns out nearly 3,000 loaves of bread a day. 56z THE ELECTRICAL EXPERIMENTER December, 1916 Electrical Xmas Suggestions ELECTRIC ELEVATOR THE CHANGE YOUR OIL LAMP TO tistic lamps are easily fastened to the LATEST TOY. ELECTRIC. limbs of the tree by a piece of wire. And We have an . ever growing list of elec- In nearly every home are stored away old when all is said and done there is no tric toys with which to delight the hearts oil lamps- relics of the dark ages of light- danger of fire as when candles are utilized. of the rising generation, but one of the ing. Every oil lamp can now be trans- most novel ones formed into an electric lamp by attaching yet seen is shown to the burner the new electric light attach- herewith. It simu- ment for oil lamps here shown. lates as nearly as This handy, inexpensive device consists possible a detached of a pull chain socket with round base office building elevator. The which fits any flat wick or center draft twelve bright colored marbles burner. It is equipt with flexible cord and accompanying each toy, when attachment plug for connecting with any placed in the chute at the top, lamp socket or base receptacle. furnish the motive power for No tools or skill are required in order the toy. By replacing the to convert the oil lamp into an attractive marbles in chute, the car electric one, and the attachment shown is the supplied in finish travels up and down continu- any to harmonize with causes the lamp shade used. Many people have ously. One marble valuable oil lamps stored away which can the car to descend, and the now be drest up in modern style at small counterweight makes it as- cost and serve not only as ornamental ob- marbles discharge A New Transparent Bird Lamp for Xmas cend. The jects but useful ones as well. This applies Tree Decoration. at the bottom particularly to the pedestal style piano and as shown. parlor lamp of a generation ago, with its A MAGNETIC ALPHABET TOY FOR This novel graceful base and silken shade redolent of toy, is equipt THE KIDDIES. the days of our grandfathers, when the The novel magnetic alphabet toy illus- with minia- drawing-room was a work of art -not a trated herewith consists of a sheet metal ture tung- repository for "canned" music and speech plate, beautifully enameled, and is reversi- sten lamps reproducing machines only. ble -the two sides being in different colors. in red and The plate is perforated with small slots white, which and in each slot there is suspended a semi- flash a ternately as the car runs down and circle of silvered sheet metal, which slides tip. The lamps can be operated by any freely through the slot to either side of standard one -cell dry battery. the plate, but is so made that it cannot This toy, with its novel mechanical move- possibly drop out. ment, the wiring, electrical switches, lamps, Upon drawing the magnet downward etc., is interesting and instructive to any over the face of the plate, the semi -circles child. The tower is lithographed in colors, of silvered metal are drawn through the the car showing the elevator operator in plate from the other side to form any front and the passengers at the rear. letter, figure or design wisht. To erase the letters or designs thus formed, the A 90 -WATT "BABY" ELECTRIC plate is tilted backward to a horizontal IRON. position. The manner in which these sil- One of the latest electric novelties is vered pieces follow the magnet is a source the electric "Baby" Iron, which is less than of never -ending delight. one -half as large- as the ordinary size For kindergarten or educational purposes household iron. It is light, compact and this novelty would seem to impress upon extremely economical. the mind as in no other way, the form of Among other things it will press 'hand- the different letters of the alphabet, and kerchiefs, fine linen, laces, lingerie, baby figures and designs of all kinds. It may clothes, cuffs, sleeves, fancy collars, ruf- also be used as a counter. It will be readily fles, and light ladies' wear of all kinds. seen that numerous games may be played Its low price and practical utility make on it, such as Tic -Tac -Toe, etc. it just the thing to give to little girls who The device is strongly made and is prac- wish to help mother with the family iron- tically fool -proof. Also there are no bat- ing. teries used in operating it, so that it be- The `Baby" is strongly built to with- comes impossible for anyone to receive a it. It stand rough handling -it is furnished with Those Who Have Valuable Oil Lamps Will Appre- shock from six feet of maroon cord and a plug suitable ciate This Electric Light Attachment, Which will last indefinitely, for attaching to any standard lamp socket. Brings Them Once Again Up-to -date. and if the steel mag- The current consumption is only 90 watts, net should wear out about one -sixth of what the standard household size iron consumes. It operates BIRD XMAS TREE LAMPS. on 100 to 130 volts. A novelty in Christmas tree decorations This little iron heats up readily for work is a transparent bird with a tiny electric in about three minutes. A wire coil pro- lamp inside it. The bird shown is half the actual size. These are made for 3% -volt battery Christmas tree outfit only, with tungsten filament and miniature base. They are made of an unbreakable transparent composition and can stand careless handling. The birds are ingeniously moulded and colored representing parrots, some with green head and tail, and white body; others red, etc. Canaries in yellow, robins, doves and others. These very attractive decorative, novelties are particularly well made A New 90 Watt "Baby" Electric Sad Iron. A Gift of Lasting Appreciation. and present an extremely realistic appearance. By Means of the Magnet Any Design Can Be tected attachment plug on the iron, en- No well decorated Xmas tree is complete Formed. Very Instructive. ables one to disconnect the iron from the now without a dozen or so of these song- cord while working. It weighs but one less, yet handsome illuminated birds. The it may be replaced by a new one at small pound. small receptacles accommodating these ar- cost. December, 1916 THE ELECTRICAL EXPERIMENTER 563 WHY TELEGRAPHERS RISE TO Pacific, Levey of the Western Pacific, TEACHING WITH THE ELECTRIC RESPONSIBLE POSITIONS. these are three of this summer's crop of STEREOMOTOGRAPH. The habit that many telegraph operators presidents who went, as a railroad poet Most persons are quite familiar with the have of climbing and reaching the top of might say, from the sounder tq the scep- method of teaching some subjects with the the ladder was recently the subject of an ter. The list of distinguished railroad aid of a text -bock, combined with a more editorial article in the New York Sun. presidents of these The article is headed "They That Desert and older days is full the Key," and we read as follows: of operators: Van "Why do telegraph operators become Horne of the Cana- railroad presidents ? The question forces dian Pacific, Hughitt itself upon the mind through the reitera- of the Northwestern, tion of facts. As often as we read that Newman and Brown the winds will be moderate and south- of the New York erly, and that Villa is dead, just so often Central, McCrea of do we read that the new head of the so t h e Pennsylvania, and so railroad began his business career Hayes of the Grand as a sender of Morse messages. Bernet Trunk, Tuttle and of the Nickel Plate, Calvin of the Union Todd of certain New England lines. A TELEPHONE THAT FITS YOUR "How telegraph op- HAND. erators become rail- While the standard form of wall tele- road presidents phone serves its purposes well there are would be easy to tell. many occasions where a handier instru- Your operator hears ment appeals; that takes up but little space. everything, knows Such a 'phone is pictured here. everything, does This style of instrument is suitable for everything. He is either office or residence installations. It awaze how far a can be mounted on the side of the busi- division superintend- ness man's desk or on an adjacent wall ent may go in spirit- The Stereomotograph -An Instrument Devised to Aid the Teaching of within convenient reaching distance. It ed debate, by wire, Difficult Subjects byyroiecting on a Screen Actual Views of the Object should be popular in the home with per- with the general man- Discussed. sons who prefer to sit down and talk. ager. He comes to know upon what days or less clear explanation by the instructor. In factories, mills and machine shops the chief dispatcher is afflicted with tan- The student is also familiar with the long this instrument gives greater satisfaction trums. He flags the night express on the number of hours that he must spend be- because no vibrations caused by running brink of the washout, supplies the jolly fore he can thoroughly grasp a subject machinery can affect the operation of the brakeman from his own paper of fine cut, like geography, botany or zoology. The transmitter while the instrument is being chops Mrs. Jones's telegram to ten words, reason for this is that he is not shown used. Other types of telephones with fills the station stove, figures transmissis- the exact things which he has read in the rigidly mounted transmitters pick up much sippi freight rates, sells excursion tickets text; consequently he is forced to read foreign noise when subjected to such local and has an eye for the ladies. On Sunday and re-lead the same paragraph in the book, conditions. afternoons, between the 2 :46 and the 5:58, before he can begin to picture the object The telephone is equipped with a trans- he plays first base on the town nine. Thus which he has studied. This, however, is mitter and receiver of standard size, and he acquires a rounded life, with the wisdom not the case with the teaching of chem- of near and far. Presently the istry, physics and allied engineering sub- boss of the division takes him jects, as in these it is required by every into his own office and his school that a certain amount of experi- doom is written. Nothing but mental work mus: be conducted, thus caus- the scythe or the bottle can ing the student to master the subject fully prevent him from becoming by actually seeing the thing which he has president of the road. been studying. "Why he lets himself be hur- Of course, th.s cannot be done with ried on down the path puzzles every subject, but there are other means us. He wears better clothes whereby studying can be made more in- as he goes on, but is obliged teresting. One p omising method has been to pinch the fine cut surrepti- suggested, involving the use of the motion tiously. He joins a country picture machine installed in the class room club, but his old place in base- to project the lesson in picture form, be- ball is lost to him. The brake- fore the students This method has often man calls him Mister instead failed on accoun' of the difficulty of ob- of Joe. Nobody flags the taining the required films. A second night express and he spends a method is to use a projecting machine week with a coroner's jury. which employs lantern slides. Coming to the presidency, he The first machine which has proved finds that the rates east and most suitable for this class of work is west of Clinton, Iowa, instead the Stereomotograph, which is a special of being horribly complicated, form of stereopticon projector. The only are ' merely horribly small. difference between The eye that once was for the the latter and the first ladies is now cast languishing- instrument is that the improved model has ly at the Interstate Commerce a special slide magazine, which holds 52 Commission. He is 55, prac- slides of the ordinary lantern type, which tically fat, and plays golf. may be projected in consecutive rotation They all play golf, these presi- at the rate of abcut four slides per minute, dents who were brass- pound- or may be controlled by means of a push ers. It seems to be part of the button at the en l of an electric cord at doom. any distance from the machine. The pic- "All in all, the operator who tures projected by this device are big falls to the position of presi- enough to be seen in a large auditorium, dent reminds one of some and our illustration shows one in use in doughty adventurer who has a fairly large class room. The instructor been lured away from adven- can ture. Time was for him. As speak on the various points of his topic with great ease. One of the Latest Designs of Telephone Instruments, Enabling he sits in his mahogany ingle- You to Sit Down and Talk, as It May Be Removed From the nook, holding out his road's The Stereomotograph is not only adap- Hook. empty bowl to the Commerce ted to educational work but has been used its normal transmission efficiency is Commission and begging for just a little with equal success in advertising, and it claimed by the makers to equal or exceed more freight rate gruel, one prefers not will undoubtedly be put to Many other all others. The subscriber naturally speaks t o remember the lad who was so free and uses which require a projecting machine directly into the mouthpiece and operates ithe and gay. Yes, 'tis a horrible fate, of this type. Photo courtesy of Charles the transmitter at its full power. ut lead us on, lead us on." Beseler Co. 564 THE ELECTRICAL EXPERIMENTER December, x916 How the "Wireless Wiz" Turned Evangelist -A Xmas Story By Thomas W. Benson DID it ever occur to you that the the drift of his line of etheric spark music. across his features, and as if talking to "Wiz" was a psychologist? No? Anyway that night "Polar" was running himself and weighing every word he whis- Neither did it to me until this along with his local throttle wide open, pered what sounded like a prophecy. "They Christmas. He is usually so smashing conventions and making a general used electrons to talk to Hawaii; they used exorbitantly optimistic that one wreck of all the beauty in the world. He them to talk to 'Frisco and now I'm going wonders how in the name of Buddha's was almost proving that everything was to use them to talk to a man's soul." sandals he ever manages to survive the hypocrisy and bluff ; all the good in the The mystical wonder of it kept me si- Yuletide season; he is fairly bubblifig over world having petered out some centuries lent; I knew he was not bluffing, was per- with good nature thruout the year so much ago and our modern conventions were fectly sane, but to talk to a person's inner that at Christmas he usually seethes with merely parodies on things as they were. being was a little, yes, just a little beyond happiness and can't stand anyone who is It was the week before Christmas, and me. gloomy. naturally the gift argument came up to the "Yes, it does sound ridiculous," he broke Just one minute, Salvador, and you will tune of some real planning. in on my reveries. "Ever hear of what see what all this has to do with the story "Gifts," he sneered, "gifts nothing. is known as the psychological moment? pretty soon. Merely a sort of here is a present, see -if- Well, at that time it is possible to play with However, he usually wastes enough time you- can -go -me -one- better sort of a deal, a person's passions and thoughts to an to find out what is the matter with the with the odds that you will get stung in unbelievable extent. All you have to do gloom-bearer, and usually finds a simple the end ! Oh, what a beautiful thought ! is to bring `Polar' over here late Christ- remedy. For instance, look at the ease Not ! It reminds one of the old horse mas Eve and I'll show you how it all

The 'Wiz' Switched Off the Lights and the Three of Us Had Settled Down 'Behind a Like Number of Thoroly Healthy 'Jimmy Pipes.' The Music Had but Half Finished when 1 Almost Sprang from My Chair in Alarm, for There, Above the Flickering Flames, Slowly Appeared the Face of HIM who Died that the World Might Be Saved." with which he made a rip- roaring, regular traders brought up to date and dressed in works out," he instructed me, and he be- optimist out of "Polar" Nolan. Now Jim a red suit with snow balls thrown at the gan testing out his burglar alarm system, Nolan was the worst kind of a joy killer - more prominent parts of the costume." which was a polite method of handing me that's why we dubbed him "Polar." He "Avast there, philosopher," broke in the my hat and coat, without the effort usu- was as nice and sociable as a hungry polar "Wiz," "how would you like me to make ally accompanying such actions. I'll tell bear' in March. The "Wiz" just went and you take back those words ?" he asked. you about that alarm system some time; -wait a minute, Ignatz, I'm getting ahead "Not that it really makes much difference no, Alphonse, it has nothing to do with of myself again. to me, but why try to stifle the good this story. It all came about this way. One night thoughts that can't help but run in your Christmas week is always a busy time the three of us were up in the "Wizard's" mind at this time of the year," he added. and I gave very little thought to the com- "lab "-"Polar," the "Wiz" and I. The "Can't be done," boasted Nolan as he ing experiment of the "Wiz." Caught him only thing Nolan was a bear on was his rose to go. "If I don't see you during the on the ether one night and he informed code. That boy could pound out the pret- week be sure to hang up your stocking his shot. me all was O.K. and that ten o'clock would tiest music on a key that ever disturbed for Kris -Kringle," was parting drop in. I boys, he had "Yes, I'm going to call his bluff," breathed be about the right time to the ether. And speed, why never had cultivated Nolan to any great ; fun he would shoot the "Wiz" in answer to my mental tele- it to burn just for a little in getting his wave length above the limit and when pathic question as he returned from seeing extent and had difficulty the "Ham" at the "yard" balled him out, the caller to the door. He picked up a him to accompany me, but perseverance he would come back with some of his fast new electron relay bulb that he had re- will accomplish most anything. I rounded fox -trot stuff and have the poor baby cently ordered and was toying with it. him up finally and we proceeded to the hanging on to the wireless echoes to get As he sat there studying it a smile spread Wizard's domicile. December, 1916 THE ELECTRICAL EXPERIMENTER 565

The "Wiz" greeted us cheerily and led ning. Just as it struck the other wall the a length of twisted wire from one corner us into the room where he had arranged room was brilliantly illuminated and the of the ceiling to the base of the tree. The the usual innocent looking Christmas tree. gifts were suddenly displayed as if by insulation is scraped from the top of the He switched on the lights to give us a peep magic in the little bower under the tree wires so as to bare the conductors but not at the arrangement, which short- circuiting them. A was to his regular stand- small carbon ring is released up iyall Ta/se ard. He had succeeded in p/oce Ficro,ohone) by a magnet and sliding getting a very attractive ef- ! ,//.,, down the wires, makes fect in a novel manner. In- . ~ c/oc/f cor_nections with them, thus stead of the tree standing / gY forming a spasmodic arc upright it was apparently "/ that travels rapidly the broken off about one foot whole length of the wire. from the bottom and leaned "On its striking the base against the side of the room. Te/ coli of the tree, the traveling It also seemed as if part of ring swings against a con - the branches had dropped tact that ignites a charge down and away from the of smokeless powder and by trunk of the tree proper, means of a magnetic release thus revealing the gifts dis- /omo the twisted wires are de- played. f/ec! tacied from the tree base "I'll show you the main and swing back against the idea of it," he said, switch- wall, thus being unnoticed ing off all the lights. In the ,4pooren/ when the room is lit up. dark we heard him fixing offace "The boughs of the tree something about the tree are bound together by fine for the rustling of the ;t wire, which also holds up boughs was plainly heard a compartment for the gifts. as well as several faint This compartment is made clicks. Ges log firme from a shallow box covered In a moment he closed a wita boughs from a tree and switch and the room was r hinged so that it can be faintly illuminated; j u s t swung up in back of the sufficient for us to make Loadla/Áer tree proper. Thus the box out the objects therein very is dly, noticeable in the indistinctly. And how unin- ..;j,in ht, but as the tree teresting they seemed. The is pulled over by the action tree was now standing up- of a weight as soon as the right, no trimmings being Schematic Arrangement Showing How the "Wireless Wiz" Rigged Up a Concave powder explodes the fine Mirror to Catch the Reflected Image of the Photograph and to Throw It Out into plainly seen ; apparently it the Flames Just in Front of the Open Fire -place. wire binding the boughs is was the forlorn object it released and they swing out purported to be. while the other boughs flew out with their and at the same tinte the box drops down, "Now, watch !" directed the "Wiz." Sud- many colored trimmings, glittering and displaying the array of presents." denly a stroke of lightning appeared to gleaming under the electric light. "The idea is clever," complimented Po- leap from one corner of the room-a flash "It's really very simple," laughed the lar, "but don't you think you could have appeared at the base of the tree which "Wiz" as he realized our apparent amaze- made better use of he valuable time spent began to fall over as if struck by light- ment. "For the lightning bolt I fasten (Continued on page 615) SIMPLIFIED SPELLING ADOPTED to any city in it, and its flood-lighting on CONGRESS TO VOTE ON ELEC- BY THE "E.E." the eve of America's Electrical Week (De- TRIC SCORE-BOARD. Beginning with the present number we cember 2 -9, 1916) most appropriately in- By installing atti electrical score board will use Simplified Spelling as given in the augurates the national electrical celebra- Congres: expects to reduce the average publication on this subject issued by the tion starting December second. It is pro- time occupied in calling the roll from 40 United States Government Printing Office posed to reconsecrate it with the President, minutes to 34 seconds. A bill has been in- and as reconmended by the "Simplified possibly, and the Atlantic Fleet, prominent troduced to electrify the roll call. Spelling Board" during Ex- President civic and governmental officials present at a A Congressman with a head for mathe- Roosevelt's Administration. notable program of dedication. matics estimated that fifty -six days were Simplified spelling, as recommended by Thru the activities of the Society, in spent calling the roll during the last session executive, order of Ex- President Roosevelt co- operation with the New York "World" of Congress. He calculates that the House for use by all Government departments, in- and with leading Government officials would save one month out of every year, corporates a list of 300 words. and electrical engineers, plans have been besides a saving of $50,000 a year in light, Contrary to general opinion, it is not at made to lay a cable from the New Jersey heat and telegraph service. all difficult to memorize the recommenda- shore to Bedloe's Island, which will carry The device is an invention of a Milwau- tions of the Simplified Spelling Board, as current for the illumination. This will pro- kee man and, when installed, will consist will be apparent from the following ex- vide all Bedloe's Island, where the statue is of a big board upon which each Congress- amples: located, with central station service instead man's name will appear. Opposite the name Instead of thoroughly, this word is spelled of the isolated plant as was originally pro- will be a red and white bulb. At each t- h- o- r- o -1-y; instead of through, we have posed. Congressman's elbow there will be two thru; instead of thorough-thoro; in place This installation will endure as a national buttons which may only be pressed after of though-tho; in lieu of stopped, we find exhibit of central station service and, in a the individual board has been opened by stop; instead of adze, we use adz; instead picturesque way, be an inspiration for flood- the Congressman's key. of dashed -dasht, etc., etc. lighting civic buildings, arches, statuary, et The machine automatically adds the vote Copies of the bulletin on Simplified Spell- cetera, thruout the cities of America. and shows the result. It will require about ing containing the recommendations of the In furthering this project, the Society's seventy miles of copper wire. Those fav- Simplified Spelling Board and also the au- general manager, J. M. Wakeman, ad- oring the device say it will last a couple of thorities constituting the personnel of this dressed letters to all the 268 America's centuries and that it will splendidly save Board, as well as their reasons for mak- Electrical Week committees, earnestly re- its own cost. ing these recommendations, may be ob- questing each committee to set aside Sat- tained from the Government Printing Office, urday, October twenty- eighth, as "Liberty ELECTRIC SIRENS AID TO Washington, D.C. Day." This date was the thirtieth birthday OFFICE BOY. of the Goddess of Liberty, and was the last In far-away Hawaii there is an installa- PLAN TO FLOOD -LIGHT STATUE official day upon which donations were re- tion of twenty electrically operated sirens OF LIBERTY ON DECEMBER 1ST. ceived to flood -light the statue. Electrical which are distributed thruout an extensive The Statue of Liberty, gift by the Re- engineers began the installation directly sugar mill. These sirens are sounded public of France to the United States, will after. thru a push button. By a system of be illuminated for the first time with its The lighting of the statue under such dis- signals-a different one for each depart- new permanent flood -lighting on the night tinguished auspices was heralded by the ment head -a man is told instantly, in the of December first, according to a program press across the country, and the electrical noisiest part of the plant, that he is wanted just announced by The Society for Elec- industry was congratulated for its part in on the telephone, It has proved a great trical Development. thus assembling the final portion of the fund saver of office boy trips and is recom- The statue belongs to the nation and not to permanently flood -light the statue. mended for widely scattered plants. 566 THE ELECTRICAL EXPERIMENTER December, 1916 Ups and Downs of a Telegraph Line By Thomas Reed IN these days of wireless I suppose We made a minute estimate of the cost, Charles, because it's the one that Longfel- the old wire -telegraph is no longer with the aid of the arithmetic. The result low used to make poems about when he good form in Bugdom. I don't was depressingly accurate, and confirmed was hard up for subjects and the rent was blame you, Bugs; not much attraction us in our opinion of that pestiferous study due. in a line a few hundred yards long as a kill -joy pure and simple. Why arith- "River, that in silence windest when you can have the whole world, with metic should be piled on top of our other Through the meadows to the sea," a few oceans thrown in for good measure, inflictions we never could tell. We had and so on, as much as $12 worth, the way to play over ! a theory that once upon a time there was they used to pay poets. Such nice lan- Lucky Bugs ! You don't have to ring a boy who liked to go to school -doted on guage shows what a shady job can be a grouchy neighbor's bell, look him in his it, pined for it -so, to cure him of pining, done under a poet's license. He worked glaring eye while you beseech him in a they invented arithmetic and after that he that river off on the public at high tide, shaking voice, "Please, mister, can we put got healthy again and hated school as is never mentioning that when the tide was just a little bit of a wire up on your house natural. Arithmetic must have been kept out, it was composed mostly of black mud, for our telegraph ?* It won't hurt it a on the list for other reasons in our case. dotted with cans, old hats and felines nine mite, mister," and be handed back a Anyhow, it was just like that mean, close- times tired of life. That was in the old growling "No !" and a slam of the door in fisted science to take delight in showing us days, of course; it's all prettied up now your face. exactly how hopeless our wire- proposi- and called a "Basin," and if you threw a No, sir, you just snap off a spark up in tion was for, in spite of all the skimping cat in it a park cop would arrest you just your attic and it shoots out right through we could do on the size of wire and quali- as quick as he would if you pulled a and through the grouchy neighbor's house, ty of insulators the cost insisted on figur- fish out. It's strictly against the law these

' the thunder storm seemed quite tame when -bing! a tremendous ripping, tearing discharge took place. Hot arcs played about with a sizzling noise. The telegraph sounder tapped wildly, buzzed, stuck, and slowly grew red hot! The batteries boiled and gave off ugly green fumes." not to speak of himself and his Ford car, ing out at the ghastly, appalling, impossi- days to mix the land and water fauna. and everything else he owns, and he can't ble sum of seven dollars and ninety -six Well, among the other curiosities lying help himself. cents. Our total wealth was two-O-f our. on those mud-flats, we spied a big snarl In my day the grouchy neighbor was an As usual, we tried to get the old folks of telegraph -wire, with insulators attached, important factor because the wire -tele- interested to the extent of a cash invest- which had blown off the bridge during graph was all we had. It was all any- ment, with the argument that it would be some winter storm. We borrowed a boat body had for that matter. I've told you handy to exchange cake -receipts, or ask and grubbed up every last foot of it. It something about our heartbreaking strug- who was mayor this year ; things like that. was middling kinky, and more than mid- gles to make sounders and keys. When Fat chance ! Father said we were under dling rusty, but, as the fellow says, it we had them at last, our next ambition his feet most of the time, where he could looked like a string of pearls to us. We was for a line -wire; but this was a prob- talk to us vocally without expense. I then straightened it out and pieced it together. lem that gave us pause, for it meant a appealed to him as a disinterested patron Sometimes we'd have a dozen splices in- cold, deliberate expenditure of money; no of the arts; but the answer was he guessed side of twenty feet, and then it looked still help from the workshop at all. If it had if he could keep me in shoes, that would more like a string of pearls -or something. required a few strips of skin from our be about the extent of his encouragement For all our joy, though, we must have backs, the prospect would have been of science, the way business was. The en- realized that it wouldn't prove exactly an brighter. terprise languished and I guess it would ornament to the suburban home, because That so! Mr. Reed probably never approached have been doing the same yet, but for a I remember perfectly that, when we ap- a cantankerous fish -eyed, apartment -house land - big stroke of luck we had. proached the neighbors for leave to use .overlord with the modest request of sticking a Just in our time of need the Charles their houses as telegraph poles, we didn't :o -fnnt aerial mast on top of his roof! The city River stepped forward and gave us our mention how it looked. They naturally Radio Bug hasn't always a cinch of it either!! - .Editor. !ine, insulators and all. You know the (Continued on page ór1) December, 1916 THE ELECTRICAL EXPERIMENTER 567 The Marvels of Modern Physics By Rogers D. Rusk, B. Sc. COLD LIGHT. will doubtless lead to greater illuminating surprising how =ome of the simplest facts THE above title is a seeming con- efficiency at least, if not to an entirely new of experience wal help us here. tradiction, because most people method. The trend of progress in electric A pinch of common table salt (sodium are guided by common -sense, and lamp invention and manufacture has moved chloridi thrown on a flame will color it common -sense sometimes goes steadily during the past fifty years in the yellow. The cl emist knows this as the astray. The impossibilities of to- direction of cold light. That is, each suc- characteristic sodium line of the spectrum, day are the commonplaces of tomorrow, ceeding lamp has produced more candle whose position is always the same, due to power with less heat loss ; and who shall say the unvarying wave length of sodium light. AMerturÿpa/e - that in the tungsten lamp we have reached Put the salt in a different flame of quite Bf/ec%de a limit? C6/ass iimu/otü{g The radiation of light from a heated tube. substance is called temperature radiation, and this characteristic of light production is true of all opaque substances. On ' illl 111l lll lll ll l 1 I I the other hand, perfectly transparent substances do not radiate light upon being heated. Over a hundred years ago it was found that this is true of air. No matter to what temperature air is heated, it will not radiate light. The light in the ordinary kerosene lamp is due to the glowing particles of carbon. A gas jet gives off still more light because Luminescence Produced by the Passage of an Experimental Production of "Cold Light" by the particles of carbon are heated to a Electric Current Thru Sulfuric Acid -Another Passing an Electric Current Thru a Potassium "Cold Light ", Experiment which Can Be Made Bromid Solution. higher degree. In the old incandescent lamp the carbon filament could be heated to lu- by Anyone. and it is a wise man indeed who dares say minosity with less consumption of energy different temperature and still the color is that such and such a thing cannot be true. and without the filament being consumed the same. Put two different substances of Everyone knows that a candle -flame, a gas- very fast itself. Then came the tungsten this nature in the same flame, and different light or an electric lamp is hot, but it does lamp which takes only a fifth of the energy, colors will be produced. This points to the not necessarily follow that all sources of and whose life is much greater than that conclusion that temperature is not the only light are hot. The firefly even after death, of the carbon lamp. Such improvements factor concerned in producing the lumi- and when kept at a low temperature, will have been brought about by 1st, the de- nosity. It is not alone a molecular vibration still emit the same luminous glow. This mand for higher illuminating efficiency; due to the heat, but in addition -a chem- luminosity is not due to a high temperature, 2nd, lower operating costs. ical reaction ! A complete control of this hence we call it cold light, and it is possible The carbon filament lamp is satisfactory chemical reaction would give us a means in the laboratory to imitate, if not to dupli- compared with kerosene, except that if of generating cold light at will. cate the light of the firefly. made to give a higher light efficiency its It is likely that a number of chemical re- One of man's greatest exploits has been life is very short. This is beckuse the car- actions are going on at the same time, mak- the turning of darkness into day. The pro- bon vaporizes and disintegrates-i.e., it has ing the action a quite complex one. The duction and maintenance of efficient light- a higher vapor tension. The Osmium decomposition of the metallic salt is prob- ing systems concerns the whole civilized lamp, one of the first metallic filament ably a chief factor, for in the sodium flame world, and yet in the electric light it is lamps, was successful because of the low a certain amount of free sodium can he surprising what a waste of energy there vapor tension of osmium, and increasingly found and the same is true of the salts of is. Considering the gas -filled tungsten successful were the tantalum and tung other metals. Different reactions will pro- lamp, the most efficient incandescent lamp sten lamps which quickly followed. The duce different colors, and altho a complete yet produced, only 3.3 per cent of the enlarge loss by heat radiation in the tungsten tabulation of such experimental data has ergy expended is turned into light! Think lamp has been cut down very greatly by not been made, to include the multiplicity of the millions of lamps in use in the the introduction of nitrogen gas into the of reactions known to the chemical world, United States alone, and then consider what bulb. Yet, as mentioned above, only 3.3 still some progress has been made along might be done with the 96.7 per cent of the per cent of the energy is actually converted this line recently. electrical energy now going to waste. into light. If we pass a current of electricity be- The truth in the title of this paper de- It has been said that the light of the tween two electrodes thru a suitable electro- pends upon the fact that under certain con- firefly is the most efficient form of light lytic solution, flashes of light will be noticed ditions light may be produced, when if heat known. We can hardly estimate the cost at the anode due to a light -giving chemical is not entirely absent, at least the tempera- of such production, but certainly there are reaction started by the current. The pro- ture is comparatively low, and the materials no .great losses to be considered. Nature duction of light thus by chemical means is concerned are cold in the common sense of is ever economical, and we would do well called chemiluminescence, and the light is the word. It is not at all improbable that in to imitate her. only v- Bible in flashes due to film forma- the future marked changes in methods of The theory of cold light can be under- tions in the electrolyte. The best results illumination may develop from this physical stood by anyone with a slight knowledge of can be obtained by the following method principle. The subject of light is the broad- physics and chemistry. It is well known illustrated in Fig. 1. Mercury in the bot- est in all the realm of physics. Its prac- that light is given off by phosphorescent tom of a jar is made the anode by connect- tical and theoretical aspects interest both substances at low temperatures, but this ing with a wire thru an insulating tube to the engineer and scientist, and not a small is light which has been absorbed shortly the surface, and a strong solution of po- number of the latter are working on the before, and is being given off slowly. Dur- tassium bromid placed in the jar. With a ing the exposure the substance underwent current of about two amperes per square a stimulation, the effect of which lasted decimeter of mercury surface, the mercury over a certain period of time. If we had will glow with an orange light. The cur- another method of stimulating such substances, it is readily seen that a cold light of some practical importance might be evolved. However, it is not particularly these substances to which the theory of cold light refers, but rather to the general scientific causes of the production of such light without temperature radiation. It seems that light produced in this manner Light Waves From Motion of Electron Alone. must be due to some chemical action, and Here We Have Heatless or True "Cold Light." this action has actually been produced in Showing the Production of Heat and Light Waves Simultaneously by Double Motion of Electron the laboratory by electrical means. The ex- rent can readily be varied by changing the and Molecule, i. e., "Light with Heat." periment is even simple, enough to be re- applied voltage which may be as low as peated by most any experimenter. First, four volts. By using a brush pressing problems involved in the study of cold however, let us see if we can prove that against an anode in the form of a rotating .light. Aside from the very great theoretical temperature is not the only factor con- wheel B, as shown in Fig. 2, light may be interest of such investigations, the results cerned in the production of light. It is (Continued on page 616) 568 THE ELECTRICAL EXPERIMENTER December, 1916 ¡E1iithr' ftlait &tg A PROFESSOR'S VIEW. managed to renew it for two years. I hope Editor The Electrical Experimenter: Under this heading are published com- I am not too late to take in your last offer As you appreciate brevity I will not take at $1.00 per year. munications from our readers of general I up much of your space in criticism and interest to all concerned. In order that let- wish you much success and also hope THE ELECTRICAL EXPERIMENTER Will suggestions. It is simply this : THE EXPERI- ters shall receive proper attention, we earn- that MENTER has been and is exceedingly useful estly request you to make them as short and continue to prosper and grow better, much to me as Professor of Natural Sciences in concise as possible. This is essential on ac- better as it grows older. the St. Francis College. I think that the count of the great amount of mail received MRS. J. J. NUESSLEIN. department of Experimental Chemistry is daily. West New York, N.J. a good addition to the journal and I hope No attention can be paid to unsigned [We might as well admit it; we are not that THE EXPERIMENTER will continue in its communications, but on request we will burdened with many letters from the gen- present form. withhold the correspondent's name. tler sex. Somehow, as a rule, electricity I have recommended THE EXPERIMENTER EDITOR. does not hold many charms for our fair to several of my friends interested in elec- sex. Therefore the above letter is all the tricity. REV. MARCUS KREHE. more appreciated. We certainly do try to Cincinnati, Ohio. make the "E.E." better, MUCH better as [This is one of the many letters we have Offizz," "Wireless Wiz," "How -to- Make-It we go along. Sometimes we think we do received lately commenting on our new de- Department," "With the Amateurs," etc., make a mess of it; of several late issues partment, Experimental Chemistry. Next in fact, there is little that does not hold my only the November number fairly well sat- to Wireless, this new department has been attention. I have in my home a number isfied us, but we promise to do better.- most heartily received by all experimenters, Editor.]

worthy of the name. Of course the most ummiumummilimmumummitommitimitimommoommiumatittstmmmilmonnommo,,,,,. interesting installments are to come as yet. 111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111lllllll 111111101111111111,1111111. AN INDEX FOR OUR QUESTIONS AND ANSWERS. We are certain that Experimental Chem- THE JANUARY, 1917, istry will make hundreds of new friends Editor The Electrical Experimenter: during the coming months.-Editor.1 ELECTRICAL EXPERIMENTER. Reading the Editor's Mail Bag and the Start the New Year right! Become note "To Our Friends" in the Question FROM A BUSY MANUFACTURER. a regular reader of this journal and Box of the September issue reminded me Editor The Electrical Experimenter: be up -to- the- minute on the latest of an idea which I have several times Perhaps you have noticed that I do not electrical, scientific and wireless top- thought would be a big help to your maga- often enthuse, but I must at this time con- ics. The Electrical Experimenter not zine and reduce the number of unnecessary gratulate you on your November number. only tells you first -hand about all questions. Harking back to the first few numbers that these things, but just how they work. For example, I would be doing a certain you published, the changes have been so That's what we're here for-to cater experiment and some question would come rapid and numerous, as to seem wonder- to the curious and seekers after up. I would remember seeing it treated in ful. We hope that the EXPERIMENTER will knowledge. You can be entertained the EXPERIMENTER SO I would get out my be an ever -growing factor in its field. and educated simultaneously by read- file and hunt for several hours without Feeling that some of the credit is due to ing the "E.E." Why not have it ar- finding it and would then try to get along your associates as well as yourself, to those ranged ,so that "your favorite maga- without it, or be prompted to write to you. with whom I am acquainted, I would be zine" reaches your library table, as On the other hand, a question would pleased to have these congratulations ex- well as that of your friends, by mail? come up and I would not know whether it tended also. Can you think of a better Xmas gift was treated in the EXPERIMENTER, but since KNAPP ELECTRIC MFG. CO., than one solid year's reading-nearly there are so many articles in each number, DAVID W. KNAPP, Pres't. a thousand large pages of meaty, val- I would not look in it because the job of New York, N.Y. uable, scientifically accurate data. finding the information would be difficult. [In the course of a day many letters The E.E." fills the bill from Soup Why not publish a handy index each reach the Editor's desk. Not a few of to Nuts. Here's the first course for month in which each article is listed under them bring good cheer and make us feel 1917! Why miss the others? It's up its various heads, and once a year publish that what we do is appreciated. So when to you. another index which would give the same the average "Bug "-Mr. Edison calls them Electricity's Rôle in the Mining and sort of a list for all issues of the EXPERI- " Muckers"- writes us sixteen pages telling Refining of Gold, with some ex- MENTER to date? It should include every- us how much we are helping him -why, of ceptional photographs. Learn how thing in each issue : Question Box, amateur course, Editors are human after all-we a Klondike stream six miles long stations, etc. naturally feel happy about it. is heated by electricity. To save space and type, the monthly and But when a manufacturer, employing The Radio Obliterator-A Marvelous annual indexes could be arranged in an ab- several hundred hands, and who, like many Wireless Apparatus That Will In- breviated form having letters and figures more just now has serious labor troubles terfere with Any Radio -Controlled represent the subjects and number and and infinite troubles trying to get his sky- Device. page, something like a modern library cata- rocketing materials, and a host of other Flow Railroad Trains Electric Light log. For instance, A.C.D. 41, 352 would perplexing troubles ... well, then, when Themselves. indicate a subject D. under the sub -division such a man finds time not only to read our How to Read Your Own Electric C. of the general subject A on page 352 magazine, but also finds time to dictate a Light Meter. By Walter F. Cur- of the whole number 41 of the EXPERI- letter, in these strenuous times, we indeed rent. MENTER. feel that we are fulfilling our mission. It Baron Münchhausen in Another Dis- Altho your magazine is quite valuable puts steam in us and induces us to work course on Martian Affairs. By now, I believe some such plan would in- even harder -if that were possible just Hugo Gernsback. crease its value immensely. now!-Editor.] When Electricity Puts Out the Fire. PAUL H. SHNEY. Third Handsome Supplement Photo Pittsburgh, Pa. YES, THE GENTLER SEX READS of a Famous Electrical Scientist. [Several letters similar to the above are THE "E.E." TOO. Action of Detectors in Wireless Tel- received by us weekly.. The suggestion is Editor The Electrical Experimenter: egraphy. By Wilder D. Bancroft. a very good one, and only lack of valuable No doubt if some of your male subscrib- Inductance -Its Calculation and space deterred us from carrying it out. ers were to read my letter they would Measurement. We have, however, a plan under way say : "Here's another suffragette ; one is The How and Why of Radio Appar- whereby we will shortly publish one or always sure to pop up where she's not atus. Part 2- Transformers. Ex- more 25 cent books which will contain all' wanted." No, I'm not. But I would like How plains Just They Operate and the Questions and Answers that have been. to mingle my praises with theirs for THE Why. printed in the "EE" since the first issue. ELECTRICAL EXPERIMENTER. Also the Announcement of Results We believe a book of this kind, properly My husband subscribed for your maga- in the $25.00 Interrupter Contest. indexed and cross indexed, will be wel- zine for a year and I have read it through comed by most of our studious readers. with as much (if not more) interest as he Editor.] - has. I have greatly enjoyed Baron Münch- hausen's Adventures and have read them of little conveniences which have been cop- MAMMA'S JOKE. with as much interest as one of the weaker ied from your magazine. Now that our "Oh, mamma, the hen is sitting on the sex is supposed to have in the latest love subscription has expired, my husband asked vacuum cleaner !" story. I also enjoy your "Phoney Patent me to renew it for one year, but I have "Perhaps she's trying to lay the dust, dear." December, 1916 THE ELECTRICAL EXPERIMENTER 569 Dre RADIO LEAGUE HONORARY MEMBERS CAPT. W.HG. BULLARD. USN. NIKOLA TESLA. (2/AMERICA PROF. REGINALD FESSENDEN. DR.LEE DE FOREST. H. Gensxack. Manager Western Radio Amateurs Offer Their Stations to Army ASHORT while ago, when there Another interesting fact concerning this curiosity of the President of the United was general public excitement station is that these clever radio workers States as to their real worth, and assist the over the delicate Mexican situa- and experimenters have been able to suc Department of Commerce, all of whom tion and the President had or- cessfully receive two or more different sta- have rendered the amateurs valuable as- dered a mobilization of the Na- tions simultaneously on one aerial, by hook- sistance. Fifthly, to give prizes to the most tional Guard in practically every state in ing up two or more loose couplers to it. successful amateurs. the Union, two Western wireless enthusi- So well arranged is this multiple-tuning The message originated from Station 9 asts, Messrs. Frank L. Brittin and Russell scheme that it is possible for one operator XE, in Davenport, Iowa, and was relayed C. Workman of Springfield, Ill., tendered to be receiving from Germany while an- thru the following stations, on the night the use of their excellent radio plant (illus- other operator is picking up the far -flung of the twenty- seventh of October at 10:00 tration of which is given herewith, as well dots and dashes from distant Hawaii. p.m., Central Time. Starting from 9 XE as portrait of Mr. Brittin) and their serv- The receiving range of this most inter- on low power, the MSG (message) was ices to the Illinois National Guard. esting station is truly remarkable and is relayed automatically by Dr. Hall's fa- The offer was gratefully accepted by the stated to be close to 9,000 miles. The mous recording *day device at Station 9 Adjutant- general. The radio installation stations successfully copied at this Spring- XR. here shown is installed at the Brittin Drug field experimental laboratory, by Messrs. Every amateur was instructed to keep Company's store at Springfield, of which Brittin and Workman, include OUI -POZ quiet himself until sending stations had Mr. Brittin is one of the proprietors. WGG-WSL- NAJ-HO, and a long list finished. Then, by previous arrangements These up -to- the -minute wireless enthusi- of other high -powered stations of both effected by each amateur, this message was asts thoroughly enjoy operating their out- the damped and undamped type. relayed to all parts of their state. They fit. They have transmitted messages as far The station is operated under a Govern- were further admonished to listen to NAA as 280 miles away with their sending apparatus. Adjutant -general Dickson was greatly interested in the offer extended for the use of the plant to the National Guard and also in the offer of the young men to assist his engineering corps in the construction of field wireless apparatus for use in camp and at the front. This tender was all the more welcome, so far as the National Guard was concerned, for the reason that the Illinois troops were not equipped with. field wireless outfits. A number of original ideas worked out by Messrs. Brittin and Workman, but on which no patents have been taken out, were offered for sale to the State, providing Dickson his Long Range Wireless Station Owned by Two West- Adjutant- general and engineers ern Radio Experimenters and Offered to the Illi- wished to try them out. nois National Guard at the Time of the Mexican Referring to the illustration of the ap- Crisis and Mobilization of the Troops. It Has a paratus and as most every thoro -going Range of 9000 Miles. Dhoto at Left Is That of Mr. Frank L. Brittin, radio amateur well may surmise, this sta- Owner of the Station Shown Above. tion is equipt for long wave undamped signal reception. For this reason there are used extra large inductances, which may ment license, the official radio call being and NAJ on the nights of the twenty -fifth, be seen clearly in the illustration. These 9AGN. twenty -sixth and twenty- seventh of Octo- gigantic coils measure 32 inches in length ber after their routine reports and to give by six inches in diameter, and each one is this story at once to their local newspaper wound in four sections with No. 22 cot- and to notify every near -by amateur to lis- ton covered copper magnet wire, the total A NATION -WIDE PRESIDENTIAL RADIO RELAY. ten. The sending stations were selected amount of wire used being eight pounds. because they represent some of the best The Audion detector and amplifier is used Proposed legislation that endangers our amateur si ations in the country, with the for receiving both damped and undamped right to operate our wireless stations must exception of 9 XE, which, of course, has signals and the hook -up is the extremely be met with a determined effort to show never boasted of any great ranges. flexible and well -known Armstrong cir- our worth to the public as a factor in the A number of valuable prizes were of- cuit. general scheme of national defense and fered including a 1 K.W. Thordarson Trans- preparedness, says W. H. Kirwan in a cir- former ; a Tubular Audion Panel mounted DO YOU cular sent broadcast to radio amateurs and ready for use, a pair of 3,000 ohm own a wireless station, either for all over the United States. 'phones; a pair of 2,000 ohm 'phones; ten sending or receiving? If you do, On the night of October twenty- seventh, 2 filament Tubular Audion bulbs and twen- don't fail to join the greatest Wire- less Association in the country: and for the first time in the history of ty free subscriptions to a wireless maga- THE RADIO LEAGUE OF this grand Republic, the radio amateurs zine. AMERICA. If you believe in the demonstrated to the public that they can The amateurs in the many states had to preparedness of your country, if you be relied upon to help the Government. wish to help Uncle Sam, if you wish to have your station keep an eye on President Wilson; Vice - officially recognized, join the LEAGUE. a national The purpose of the Presidential relay president Marshall, and Mr. Hughes. It non- money -making organization. Beautiful engraved was firstly, to get the amateurs interested was up to the amateurs of the several and sealed certificate, FREE to all members. NO DUES OR FEES WHATSOEVER. in perfecting their stations. Secondly, as states wherever these gentlemen happened Honorary Members: W. H. G. BUL- the ether was perfectly quiet on the night to be, to give each of the above a copy LARD, U. S. N.; PROF. REGINALD A. of the Relay, it gave them a chance to of the message. The amateur landing Mr. FESSENDEN; DR. LEE DE FOREST; check up their receiving outfit. Thirdly, Hughes or one of the other two person- DR. NICOLA TESLA. to get a number of good receiving stations ages became the "first prize" winner. All Send stamp for large 8 -page information booklet. that can hear NAA and NAJ, at all times. answers to the relay, including signatures, DO IT NOW. 233 Fulton St., New York City, N. Y. This list was turned over to the Govern- etc., had to be mailed not later than elee- ment authorities. Fourthly to satisfy the (Continued on page 62o) 570 THE ELECTRICAL EXPERIMENTER December, 1916 DLPARTMtNT The Arlington Radio Station (N A A). By Capt. W. H. G.Bullard, U. S. N.

D.1 SIT ! DOT Dot Dash ! Dot Dash ! its insulation switch and short- circuiting TRICAL EXPERIMENTER.) The bearing at this (NAA) is the signal of delight switch. The base of the triangle, the dis- end of the generator is specially constructed which radio amateurs all over the tance between the two shorter towers, runs with a large flange 70 inches in diameter, United States listen in for at 12 approximately magnetic north and south. which supports the casing for the gap noon and 10 p.m. daily. At these hours Two hundred and seventy -five tons of steel rotor. The casing, which carries the sta- Arlington sends out the correct time via were used in the construction of each of tionary electrodes of the spark gap, is radio which is received by amateur and the smaller towers, and 500 tons in the fitted so that it can be moved backward or commercial stations for a radius of 3,000 larger one. forward by a worm gear. Provision miles is and snore. The Arlington station, The current as supplied is 3 phase, 25 made to cool the stationary electrodes by located at Radin. Va., operated by the U.S. cycle, (.600 volts; and after entering the running water thru them. The requirement that the stationary electrodes may be moved is very essential, as any small changes in the .variable factors which produce changes of wave length tend to cause the sine wave of the alternator to lead or lag, and it is necessary to move the electrodes so that the sparking will occur at the peak of the wave in the condenser charging current. The main leads of the generator run to a panel on the switchboard, and after passing thru a circuit- breaker, carry current to the primary of the transformer. The wiring diagram is shown in Fig. 4. One of these leads is broken by a large relay key, and shunted around the relay contacts is a large, variable current capacity, resistance Fig. I, at Left) View of the 450 and 600 Ft. Skeleton Steel Towers at Arlington (NAA) from where Uncle Sam Sends Out grid which takes Wireless Messages to Battleships Thousands of Miles Away. Fig. 2, (upper right) View Looking Up One of the Masts. Fig. 3, (lower right) Base of a Mast, Showing Massive Insulator and Lightning "Ground" Wire. care of the considerable current in the Navy Department, signs the call of "NAA." basement it is transformed to 220 volts. primary from the time the circuit- breaker The accompanying photographs and dia- The first set installed in the Arlington is closed until the condensers are almost grams illustrate some of the interesting station was a spark set constructed on the up to the point of discharge. When the constructional details of the towers and Fessenden system. The main driving unit key is closed and opened the greater part of wireless apparatus. is a 200 horse power, 220 volt, 25 cycle, 3 the current is taken up by the grid, and The site finally selected, being the pres- phase synchronous motor, 300 revolutions this serves the double purpose of protect- ent one, was formerly a part of the Gov- per minute, controlled by means of an oil ing the contacts from wear and of keep- ernment Reservation known as, the Fort switch with auto -starter. On this motor ing the condensers constantly up to the Myer Military Reservation, and the ground, shaft, and driven by it, is an 8 kilowatt, sparking point, ready for instant discharge. 13.4 acres in extent, was transferred from 110 volt, direct current generator which This relay key is operated by a small the War to the Navy Department by act is used to excite the fields of both the 200 sending key in the operating room or at of Congress. A general view of the towers horsepower driving motor and the driven any other distant point. of the station after completion is shown in 100 kilowatt A.C. generator, which fur- The secondary leads carry current from Fig. 1 while Fig. 2 shows the view looking nishes the energy for the transmitting ap- the transformer at 25,000 volts to the sta- up one of the masts and Fig. 3 the base paratus of the radio set. tionary electrodes, and shunted across the and ground lead of one of the massive The 100 kilowatt A.C. generator is a 220 electrodes is the usual closed circuit, con- towers. volt, 500 cycle machine, and is driven at 1; taining the H. T. condensers and primary The average elevation of the space on 250 revolutions per minute thru a leather inductance of the oscillation transformer which the towers are built is about 190 belt by the 200 horsepower motor. On the in series. feet above sea level. The view shows three generator shaft is the rotor, or moving The primary inductance is a special helix skeleton steel towers, one 600 feet high portion of the synchronous rotary spark made of ten turns of one inch copper tub- from the ground, the other two each 450 gap, which consists of a fiber wheel with a ing about four feet in diameter, fitted with feet high. The centers of the towers form heavy brass ring on its outer circumfer- suitable spring clips by means of which the an isosceles triangle, the base of the tri- ence from which protrude 48 copper tract- leads can be clamped to any turn desired angle being 350 feet long and the altitude ors, each about ten inches long. (This spark for varying the sending wave lengths. 350 feet. Fig. 3 shows one tower leg with set was illustrated in the Dec., 1915, ELEC- The condensers used are of the comprest December, 1916 THE ELECTRICAL EXPERIMENTER 571 air type. Each consists of a large cylindri- are attached to spreaders made up of three lengths of wire bt.ried in the ground at cal metal tank. in which the plates (about inch pipe, 88 feet long, reinforced by various depths in the space near the tow- 200) are suspended; one set being con- trusses; and the spreaders are attached to ers, and laid in a perfect checker -board nected to the tank itself, and the other set connected by a rod thru an insulator running thru the center of the cover. A lead Ca washer under the rim of the cover and a Pennant, f lead bushing around the insulator, insures fo"f/ectrase A .0045 /250 the tank being air -tight. The plates are /nsu/afo,f A-B .0075 /900 spaced one- eighth inch apart, and at that A*BC .0090 2/00 distance would not stand the high voltage /Offer grounded were it not for the comprest air. Center ono' trvo Each condenser has a capacity of 0.036 oa/side co/x/ac%rs Mf. (microfarad) ; 14 units being used in 7 fir %o O//others multiple series (two sets of seven in parallel and two sets in series). 10 The secondary of the oscillation transformer is made up in the same manner as the primary , but is of three -eighth inch copper tubing and has twice the number of 23'rites turns. One lead is taken off to a hot wire ammeter and from there to the ground; the other lead has a spring clip and can be connected to any turn of the loading coil Jilicon bronze or antenna inductance. The adjustment of Phosphorbronze the oscillation transformer is made as nearly correct as possible before the spark is turned on; then the loading coil, which Ran ofaeria/ has similar contacts, can be revolved while the spark is in operation so as to bring the 350' antenna (and secondary circuit) into res- 336' onance with the primary. This is done by watching the reading of the hot wire am- Rottoi/ meter and moving the loading coil until 3/5' maximum antenna current is obtained. The primary of the oscillation transform- AT 3- /e P/eC/rOJe er has a screw attachment by means of . which the primary can be moved farther SE/ %/7SU/O/ors away or nearer to the secondary, so to IS obtain the proper amount of coupling to ensure a sharp or pure wave, The antenna lead is taken from the loading coil to a switch on short masts outside the building, the lead passing thru an Elec- Fig. 5. Plan View of the Main -Antenna Supported in Triangular Form Between the Three Masts at trose insulator fitted in a plate glass one Arlington, with.the Rat -tails Taken from the Middle of the 350 Ft. Central "T" Span. inch thick and five feet square! The switch on these masts is controlled by a lever and the towers by 10 Electrose insulators be- pattern with soldered junctions. Miles of sprocket chains from the sound proof tween them and the towers. A general this wire were laid, making a large net- operating room. plan view of the construction of the an- work and finally heavy wire leads are run The huge antenna is made up of three tenna is shown in Fig. 5. It is open at the down the slopes ending in a small stream sections, 23 wires in each section, each wire highest end, at the 600 foot (183 m.) tow- that flows near by. The ground connection er, and two sections are brought between the antenna and this net -work is down to the 450 foot (137 m.) made thru a large copper strip 6 inches towers and there joined to (15.2 cm.) wide and % inch (6 mm.) thick, the main section by jumpers, run to the ground wires and permanently made up of 23 wires bunched in soldered to them. the form of rope. The main} The receiving cr operating room at section is what is known as a Arlington station was built to be sound- "T" antenna, and the vertical proof and is constructed somewhat like a part (rat -tail) is taken from refrigerator with double doors and walls the center. The 23 wires of the 20 inches thick! Before the plastering was rat are brought down in the put on, the ceiling. walls and floor were -tail ir,ch (1.9 fan 300 feet (92 covered with a / cm.) "Linafelt" shape of a for for sound- proofing, and then a layer of m.) and then in the form of a chicken wire of '4 inch mesh was secured large cage the rest of the way over the Linafelt. The meshing was care- to the switch on the short pole - fully (elec trically) connected together, and mast. then several strips of copper were soldered The above antenna arrange- to it and taken to the ground connection ment gives a fundamental of outside the building to make a screen for 2,100 meters with a capacity of the receivers, so that any induction effects 0.0094 Mf., and can be readily from the generator would be absorbed by switched over by means of a the screen. switch on the pole mast for use The roam is ventilated by two small fan in transmitting or receiving. In motors, 220 volt, 25 cycle, 3 phase and the the latter case it forms a very air ducts have b zffl' plates lined with felt efficient arrangement for receiv- on the same principle as a muffler or ing long waves, as it is not nec- Maxim sillencing device, so that the air is essary to insert an inductance of silent when it reaches the room. In the necessarily high resistance. For air duct is a radiator from the heating sys- receiving shorter waves, a small tem to heat the air for the room in win- antenna has been put in place at ter months. a height of 300 feet (92 m.) and The 5 Kilowatt Spark Set: The second is used also in transmitting with set installed in the Arlington Station was a 5 kilowatt quenched gap trans- a 5 kilowatt spark set. The motor gen- Fig. 6. The 100 Kilowatt, Undamped Wave, Arc Transmitter at Arlington (extreme left) and Huge Tuning Inductances for lt. mitter, which is installed for erator of this set, which was especially de- local work, such as that with signed for this station, consists of one 15 consisting of 7 strands of number 20 phos- ,Philadelphia, New York and Norfolk and horsepower, 3 phase, 25 cycle A.C. motor, phor bronze. (Diameter of number 20 with nearby ships. one. 10 horsepower D.C. motor, and one 5 wire =0.032 inch or 0.081 cm.) These wires The ground connections consist of many (Continued on page 610) S 72 THE ELECTRICAL EXPERIMENTER December, 1916 The Revolving Mirror for Determining Spark Characteristics 4 By Samuel Cohen ONE of the most interesting pieces means of three 2 -inch wood screws. The to the instrument and other objects which of apparatus that a radio experi- distance between the upright bearings are near by. Do not stand in direct line menter or investigator can possess Should be 6 inches. with it when first trying it out. is a revolving mirror used for ob- The next piece for consideration is the The first experiment is to observe the serving and recording the fre- mirror B and its frame A. The frame is number of smaller sparks that produce the quency of a spark discharge, and also the made of smooth, flat strips of wood, such single large spark, visible to the human time between two succeeding sparks. The as mahogany or birch, the dimensions of eye. To do this it is necessary to place a apparatus as described, can readily be con- which are 5 /x4x1/ inches. On the ends spark gap about six inches away from the structed by the average experimenter who of the frame two small metal flanges are revolving mirror, and connect it to some fastened, exactly in the center, by means of high voltage device, such as an induction small wood screws, and on one is secured a coil, transformer or Wimshurst machitie. brass shaft E, about 1/" long by A" in di- Now by permitting a discharge to pass ameter, while on the other side a similar through the gap and by revolving the shaft is placed, but this is 3 inches in length. mirror at high speed, the image reflected These shafts can be fastened to the flanges in the mirror will be somewhat like that by either threading them or else by solder- illustrated in Fig. 3. It should-be under- ing the shaft and flanges together. The stood that the experi- former is preferable. Having fitted on ments herewith outlined the shafts, the complete frame is then set are to be carried out in into supports D. an absolutely dark room. Two well -silvered mirrors are now ob- In order to obtain the Typical Revolving Mirror, Motor, Speed Counter, tained. They are ordinary flat mirrors, best results from the ap- Photo Plate Holder and Oscilloscope Tube as Here Described. 4x2/ inches. A great deal of care should paratus, a special type of be taken to see that the polished surfaces spark gap in the form possesses simple wood and metal working are not scratched, as the successful opera- of an oscilloscope tube, tools. The complete instrument in detail is tion of the complete apparatus depends Fig. 4, is needed. It con- shown at Fig. 1, while its operating position upon the condition of the mirrors and the sists of a glass tube with is shown in Fig. 6. manner in which they are handled. The two plain electrodes. The The essential parts of this revolving mir- mirrors are secured to both sides of the tube is filled with nitro- ror apparatus are the mirror, supported on frame, by means of light brass strips, bent gen gas under slight a suitable frame and revolved by an electric to the form indicated in Fig. 2. The two pressure. These - tubes motor, a speed indicator, an oscilloscope long strips are 5Y8" while the other two c a n be obtained f o r tube (used instead of about two dollars from a spark gap), and a dealers in X -Ray appara- plate holder contain- tus. This tube is con- ing a photographic nected through a very plate. high resistance, such as a tube containing water. The various parts The image obtained from will be individually, this arrangement is described in detail. shown in Fig. 5. The The first in consid- l oscilloscope tube is usu- .,.._``, eration will be the re- < o.`v\ ally kept in a box, so volving mirror mech- that it will not be dam- anism. This consists aged. Fig. 6 shows the of a hardwood base complete arrangement of 12x5x1 inches, upon the revolving mirror which two uprights, Working Drawing for Constructing Two -reflector Revolving Mirror Unit tube case and the photo- D, are mounted. graphic plate holder for permanently These uprights are made from the same are 3h" inches long. Each is fastened recording material as the base, but 4" in thick- to the the spark train on a pho- frame by three round -head wood to plate. The long slit ness, while the balance of the dimen- screws. Care should be taken to see that sions are given in Fig. 1. A Y8" hole is in the front of the case the screws are not tightened too much, allows t h e constantly bored in each end of the standards D, Y4" as it may cause the mirror to crack when from the top as seen in the end view, and varying light of the tube the frame is revolved at high speed. It is to pass through to the therefore advisable to place strips of felt mirror. The length of between the clamps and mirrors. the opening depends up- With the mirror and its frame care- on the size of the tube. fully set into their proper places, the motor The shape and size of G is set up. This can either be of the the case can be made to battery or 110-volt type. The motor is suit the experimenter, as mounted on a wooden block J, the dimen- it is a minor point in the sions of which are not given in the draw- operation of the appa- ing, as it depends entirely upon the size ratus. of the machine, and if a high motor is One may ask what is used the block will be unnecessary. The the value of this instru- Fig. 3. Photo - motor and mirror shafts are rigidly con- ment to the electrical and graph of Spark Image Observable nected by means of a collar or sleeve F, radio experimenter ? The on Revolving Mir- which is made from a brass tube about question is most readily ror Here De- answered scribed, the Spark %" long, with a diameter large enough to in this way. Occurring in permit of boring a hole for the motor and Suppose it is necessary Plain Gap. mirror shafts. On the opposite end of for one to determine the the motor shaft a revolution counter shape and characteristic properties of a cer- (speedometer) H is fastened by means of tain alternating current, produced either by a bracket shaped as indicated by I in Fig. an alternator, spark or arc, transmitter. 1. The completed instrument should be This can be done firstly by plotting a curve carefully sand -papered and finished with of the current by obtaining different values of it during certain intervals of time and shellac. ' The instrument is now ready for use. then tracing the curve, but it requires com- Mirror with Brushes plicated and delicate recording A Different Style of Revolving The first step is ' to test the mechanical instru- and Commutator for Opening and Closing Spark Generating Circuit. strength of the parts when the complete ments ; secondly, the curve can be actually device is in operation. Care should be photographed by employing the apparatus these are used to supporta shaft E. The taken to see that no obstacles are near the described. Then the curve can be meas- supports are then fastened to the base by revolving mirror, as it may mean damage ured at different points, thus giving the December, 1916 THE ELECTRICAL EXPERIMENTER 573

exact conditions of the current at any in- until a clear image is obtained, or it must time interval between two successive waves terval. In either case the latter method is rotate in proper step with the groups dis- the following c.irections must be closely fol- usually best adapted for general work, as it charges. The speed is then correct for lowed : First it is necessary to employ an recording the wave train photographically. apparatus that alternates at a given known In the same manner, undamped waves can period of time, such as a vibrating dia- be recorded, and their characteristic prop- phragm acting in front of a flame, a rapid erties studied. This will also show the discharge of a spark of known frequency or working conditions of the transmitter. As an alternator c f known periodicity. Some an example, suppose the mirror rotates at such apparatus must be used to compare the 60 rev. per sec. when the spark image time of the tested spark and the spark of observed is clear. Multiply this by 2, giv- known frequency. The simplest instrument ing 120 as the wave train (group) fre- is the vibrating diaphragm acting in front of quency. Further, the time period of a an incandescent electric lamp. The vibrat- single spark, also its frequency, may be ing diaphragm apparatus can be cheaply ob- determined- by knowing the speed of the tained from an old clock, using the escape- rotating mirror and the dimensions of the ment wheel as the diaphragm, and close be- apparatus, which gives the velocity with hind it a ten candlepower incandescent elec- which the spark image moves across the tric lamp. Both of these should be placed photographic plate. The distance between in a suitable case in front of which an or- two adjacent light peaks corresponds to dinary condensing lens is mounted. A the time of a half period of the oscillation. camera lens can be successfully used for Twice this value gives the time period of this purpose. The speed of escapement must Fig. 5. Photograph of Spark Train as Obtained one cycle. The velocity of the image in be carefully with Oscilloscope Tube Apparatus Shown in determined by either counting Fie. 6. cms. per second divided by the pitch of a the number of revolutions by a speedometer peak in cms. gives the frequency of the or figuring it out by counting the number oscillations per second. of teeth of the main.drive and substituting is far more simpleSto handle than the for- Mathematically considered the mer. natural the values of every wheel that goes through, Let us take an example : Determine the characteristics of a damped wave (spark) radio transmitter. The oscilloscope tube is connected in series with the ground and Ti'/I7iny opporotus Oscilloscope cose the apparatus excited in the usual manner. If the spark image is observed in the revolving mirror, it will be noticed that a series of damped waves or flashes occur, and if one desires to record these it is only necessary to put a photographic plate in the holder, and place it below the tube case as indicated in Fig. 6. The revolving mirror will reflect the light emitted by the oscilloscope tube to the plate, and cause an impression to be registered upon the Pix2.+`o latter, which is then developed and fixed plote just as if it were exposed in a camera. ho/der The only difficulty encountered in recording the wave in this way is that, a /Voter series of waves are simultaneously recorded on the plate, which makes it impossible to. detect the one which is required, owing to the unequal exposure of the plate. Revolving_ A very simple method of overcoming this fig 7 is to operate the high tension transformer Mirror or coil. for very small intervals of time, corresponding to a dot or short closure of the key. In this manner a single spark Re9d. gore train image can be obtained. ' Another Y A L A method of obtaining the same result is to V V V slowly remove the slide in the plate holder Fig. 6 JioDdord gore until the entire plate is exposed and then 0 instantly shutting the power off. In this General Lay -out of Revolving Mirror, Oscilloscope Tube, Prate Holder Spark Generator, and Timing way a continuous image of the wave is Device Which Reflects a "Known Time Value" Curve on the Plate as Shown at Fig. 7. obtained. A moving picture film can be successfully employed in recording con- frequency N, per second, of condenser dis- before driving the last or escapement shaft. tinuously the spark image obtained from a charges is: The result must be multiplied by 2; to yield 1 the correct number definite transmitter under continuous test N of alternations given by when desirable. 2A/LC the diaphragm to the beam of light as it In order to obtain the frequency of the breaks up the light beam twice at every sin- where L is the inductance of the circuit gle revolution of the shaft. oscillations which have been photographed in henrys C is the capacity in farads. on the plate, it is only necessary to deter- Haying done this, the next step is to ar- Also the period T of an oscillation is range the apparatus as indicated mine the time between two adjacent light given by the rule: in Fig. 6, strips of the image. The group frequency 4and have the light from the electric lamp is obtained by noting the speed of the T in seconds = =2A /LC of the timing apparatus focused on the re- mirror per second, and multiplying this Ñ volving mirror in such a manner that it will cause the reflected light to fall near the bot- figure by 2. The result obtained will be The damping of a spark train can ' be the number of group oscillations (complete obtained by measuring the amplitudes by wave trains) in the transmitter discharge means of a finely graduated ,scale of two f/e%odes per second. However, it must be under- successive peaks in the same direction, and stood that the mirror must be revolved dividing the lesser amplitude by the greater at a speed sufficient to make the oscilla- one. This will give the percentage of tions visible, thus recording a radio fre- damping of the particular spark used. The quency current ; i.e., the mirror must be logarithmic decrement is obtained by mul- revolved at a higher speed than when a this result by Oscilloscope Tube in Which Spark Must Take tiplying the natural logar- Place to Obtain Shown in Fig. 5. low frequency current is to be recorded. ithm (Naperian 2.718)), or by multiplying Results This is best determined by experiment, the common Brigg's log. by 2.303 which tom of the photographic plate, while the or by observation at first. The mirror converts the result to the natural logarithm. light from the oscilloscope tube is to be should be regulated when in operation, Ordinarily if one desires to obtain the (Continued on page 59o) 1916 574 THE ELECTRICAL EXPERIMENTER December, Anent the Audion By Dr. Lee de Forest t NQUESTIONABLY no one in- was first the electrons from the hot elec- called it a grid -and a grid it was gen- vention in the radio art since trodes, and second ionization of the gases erally termed, until the efficiency and all - the original discovery of the ef- which these electrons produced, which es- around merits of the little member began ficacy of the upright radiating tablished an electrically conducting state, to become startlingly evident and well re- antenna has aroused so much in- extraordinarily sensitive to any sudden cognized. Whereafter certain experimen- terest, discussion and futile ire as has the change in electrical potential produced on ters (notably Pierce of Harvard) began Audion. In fact, the Audion and not the the electrodes from some foreign source. to write in tardy patents and begrudging, "I.R.E." has put the ire in wireless But how many trailers -after have fought text -books, of "screen"-"intermediate -elec- The manner in which the germ idea came these facts. Here comes Prof. Fleming trode" and what not. Trivialities truly, but to me of the "heated gas" detector, which claiming in his first patent the dis- strange nevertheless. But "screen," inter- eventually evolved into the Audion of later covery of the Edison effect (which he had mediate, input electrode- masked by what- years-is probably now too well known to been describing and explaining for ten ever title you choose-honestly isn't that require retelling.* years prior). Fleming is very explicit as little grid electrode a veritable nomenclat- Suffice it to say that in 1900 I became to just what he wants to do- rectify high ive accelerator? And isn't it the sine qua convinced that in gases immediately sur- frequency (as distinguished from low fre- non of every "Gas relay " -"Electron re- rounding an incandescent body, or elec- quency) oscillations -and for one purpose lay"- "Valve relay," "Vacuum tube re- trodes, resided latent forces, or unrealized only -to quantitatively measure the same in lay," "Fleming Oscillating Valve," "Plio- phenomena, which could be utilized to make a D. C. galvanometer. And he is quite tron," "Reisz tube," "Thermotron," "Aud- thereof a detector of hertzian oscillations honest at first, saying right out that the iotron," etc., etc., ever produced since that far more delicate and sensitive than any valve is a poor detector -just like that. contemptible little patent of 1907? And known form of detector. However, witness the subjective psychology. isn't it strange how shy sapient writers on The Commercial Audion was therefore In 1908, two years after I had described modern radio receivers and generators are, no accident nor any sudden inspiration. It the two electrode Audion with its "B" when it comes to describing the trifling part resultEd from long hours of search and battery circuit and its genuine relay action that grid electrode plays in the radio art patient development. I first thought to find -providing a detector far more sensitive of to -day? the imagined effect in or about the brightly than any other then known -and after a All this, however, does not deter a num- incandescent mantle of a Welsbach man- thoro correspondence course back and ber of ambitious investigators from plot- tle. This was in September, 1900. And forth, in the columns of the Electrician - ting a series of curves -all showing that yet a recent judicial decision has stated that Prof. Fleming sees a great light, and brings the principle of the Ediso -Fleming valve "an incandescent body was the furthest out a brand new patent, this time showing controls completely the action of the Aud- from my thought." the "B" battery (masked as a potentiome- ion -that rectification from cold to hot I next explored the Bunsen burner where ter across a far too large "A" battery). electrode is the key to the whole business. again I found (not unnaturally) that small And now blandly he states that "he finds Of which a little demonstration is apro- platinum wire electrodes in the flame be- he can use the `valve' in another manner." pos :-If the three electrodes in an Audion came incandescent. But here I did first True for the Professor, so he can -and are all made in filament form and all three find the detector effect I was searching for, does. are heated to incandescence, from separate and had determined must exist. Next the But long before the two- electrode re- batteries, the rectification action of course incandescent gases of an electric arc were lay-Audion of 1906 had a chance to prove ceases; so that the device used as an Edi- investigated; hot mercury vapors of a merits worth in widespread commercial use, I so- Fleming valve is a complete failúre. - cury lamp were considered ; and likewise had found that the influence of the Hertz And yet as an Audion detector the bulb the action in the still more attenuated gases ian impulses could be better imprest on works just as well as when two electrodes in an ordinary incandescent lamp surround- the conducting medium of the Audion from are cold and only one hot. The "anode" ing an ordinary incandescent filament. a third electrode. This, quite naturally, is whichever hot electrode is connected to Unfortunately during these years I was was at first outside the bulb, an arrange- the positive terminal of the B battery. It given little time to concentrate on any lab- ment "re- discovered" in 1916 by one Moor- can be hot or cold. Ditto the grid -it is oratory problem -and yet less opportunity head. But if the third electrode outside whichever electrode connected in the cir- for conducting a line of experiments in- the bulb was an improvement, why not cuit as the "grid" electrode should be con- volving such complications as the construc- still better inside, where its charges could nected. It can be hot or cold, indiffer- tion and ex- ently. Any rec- haustion of tification 'twixt various forms Audion with o// hot and cold incandes- f,'h Rh, electrodes i s of AudionWi/ho//i 3 e%c/rodes cent lamps. e%/rodes heofed wholly inciden- Hence, until heated tal, and is not 11/ the Audion ac- 1905 I was pre- -11111Fi vented fro m -111I1j C tion at all. putting to actu- c' !6 r bot 6v'bot Of course al proof my this one simple n- theories t h at LC. LC little demo the same de- stration proves tector which I beyond all the- had .predicated ory, dispute or a n d actually f / cavil, that the found in the Te/ Tel/ Fleming - Mar- n e i g hborhood coni school of of an incan- Rh; (NJ writers are fun- descent plati- 'wpm N d a mentally num wire o r wrong, and yet, carbon filament looking back 6V Bot just a little, the in a gas flame, 6 x Bot existed also in G grid Audion the vastly more 11111 / I1I1I- -1111--7 -III has made good. attenuated gas /f i/80/ First there's surrounding the f/V Bo/ t h e telephone filament of an fig. fig. 2 fE relay - licensed incandescent in 1913 to the lamp. In one American Tele- An Unusual Demonstration of the "Audion" as a Detector of Radio Currents as Given in Court by Dr. de Forest. Tel- case the heat All Three Filament Electrodes Were Heated; Figs. I and 2 Show How the Three Incandescent Electrodes Were Trans- phone and of the burning posed in the Circuit; F Serving as "Filament," G the Grid and W the Wing. egraph Co. gases There are in heated Am- the electrodes ; in the other the electrodes more directly influence the ions, and elec- use to -day hundreds of Audion heated the remnant gases. But in both it trons, one, the other, or both, which were plifiers, in all the long distance lines of the ordinarily, orderly conducting the current Bell Companies. Telephone engineering tWritten exclusively for The Electrical Experi- from anode to cathode? So I put it inside had waited twenty years for the repeater menter. which would make possible genuine long *See paper on "The Audion" Amer. Inst. Elec. -this third electrode -and in the form of Engineers, Oct., 1906. a grid. And quite naturally, therefore, I (Continued on page 617) December, 1916 THE ELECTRICAL EXPERIMENTER :75 Efficient and Economical Method of Utilizing the Arm- strong Regenerative Audion System for Damped and Undamped Waves By Samuel Curtiss, Jr. BEFORE going into detail regard- the coil, and secured to binding posts firmly can best be determined by first placing the ing this arrangement, the reader belted to the tube itself, which may be of coil L3 inside L2 and reversing the leads should be given to understand that fairly thick cardboard. Contact is made of L3 until satisfactory results are obtained. the accomplishments made possible with these binding posts by means of a clip A few precautiinary measures to be fol- by use of same can be duplicated having an insulated handle. The loose lowed in constructing this outfit are : in the without the use of the transfer switch. In coupler LC is composed of two cardboard construction of the loose coupler LC no doing this, however, the use of additional drums twelve inches in length, the outer one metal rods should be used for the secondary instruments is required, such as extra con- being ten inches in diameter and the inner to slide on as this will cause losses in the densers, a second Audion cabinet, or addi- one nine inches. The primary is wound circuits. Wooden rods may be used, or the tional inductances. The writer, having with No. 20 D.C.C. and taps are taken off coupling may De varied even without rods taken into consideration the fact that most at every 25 turns, the remaining 25 tapped i. e., by placing the primary and secondary experimenters obtain their apparatus with off singly, in orkler to secure a fine varia- in inductive re:ation to each other. For arc some difficulty, and have to make what they tion of the inductance. The secondary is signals a rather loose coupling is made pos- have, "go" its limit in accomplishing the also wound with No. 20 D.C.C., but is tap- sible, and with a set of this description sig- desired results, has designed this system ped off at every 30 turns. nals have been read with a distance of fully with this very view in mind. It can read The inductance L2 is the secondary load- five feet between the primary and secondary ily be seen that only two variable condens ing coil, and also acts as the pick-up coil for coils. Care should also be taken that the ers are used, whereas at least four would the oscillations transferred from the plate coils are not shellacked, as such a practice be required in the same hook -up without the circuit of the Audion. It is constructed causes hysteresis losses when working with transferring arrangement. The same arc signals. If there is danger of idea applies to the Audion, tele- the wire coming loose, the coils may phones, batteries, etc. If it were be given a thin coating of paraffin. desired to transfer from one set to In regard to set "B," the induc- the other by the mere throw -over of Se/ B" tance Ll may be a standard loading the antenna, it is evident that, un- Set ,":1" coil such as put out by the Electro less time were taken to change con- Ll Importing Company, and the loose nections, it would require such ad- coupler may be any instrument hav- ditional instruments as I have men- ing a reasonably high wave length tioned. for spark signals. An Electro Im- The apparatus used in making up porting Company Professional type this system is very inexpensive and loose coupler was used in the tests a large part of the material is usual- made with this system, and gave ex- ly found in the average experimen- cellent service. The inductance L2 ter's workshop or about his present of this circuit is used in connection receiving set. The transfer switch, with L3, and the two should con- for instance, may be a small three - stitute a transformer. The two coils pole, double -throw knife switch are alike in construction excepting which costs between fifty and sixty that L2 is tapped for every ten turns. cents. The inductances, outside of Both coils are 4 inches long, the one the loose coupler in set "B" can be with the taps taken off being 4 inches wound in a couple of hours, and the in diameter, and the other one 3% loose coupler in set "A" need not be inches in diameter. These coils an elaborate affair so long as it pos- should each be wound with 50 turns sesses sufficient self inductance and of No. 22 D.C.C. Relatively close a wide range of coupling. The Au- coupling is required between these dion bulb need not necessarily be of coils, and when the number of turns the most costly type, but can be any II I II II is decreased in L2 the coupling one of the tubular Audions. These should be tightened. bulbs give exceptional satisfaction in ffPBaf In the operation of set "A" the in- connection with this system, and if ductances should be roughly adjusted the experimenter should happen to rowan, to a certain wave length and the be an owner of a frozen bulb, or one Audion turned on to ordinary bril- that will not oscillate properly, he Rh. liancy. The coupling between L2 will find that in most cases it . will G and L3 should now be closed up oscillate with this system. It is only --j-+8 until it is at such a point as to cause by virtue of the magnetic coupling a characteristic "plucking" noise in between the grid and plate circuit EE the telephones. The system is now that this feat is made possible, as Regener-ofiveSysfe ready for the reception of undamped different bulbs have been tried out Arinsfr'ong" waves, and by following out the on other hook -ups and the results {l'are/e/2gf12 R077ge 200- i35o0 iYlefes usual method in tuning for these sig- could not be duplicated. nals, a pure musical note may be ob- In regard to the immediate con- A Composite Regenerative Audion Receiving Hook-Up Ada pted tained of any frequency, in the tele- of system, the conden- to Spark or Arc Signals at Wave Lengths of from 200 to 13 .500 phones. Different values of Cl may struction the Meters. Requires Minimum of Apparatus and Has Been T vied sers used are the regular Electro Im- Out Thoroly. be necessary to allow the system to porting Co., 43 plate variables hav- properly oscillate. ing an average capacity of .001 micro - identically the same as Ll, the primary ,n the operation of set "B" the usual rou- farad. Such condensers are reasonably loading coil. The inductance U is the driv- tine is followed in tuning for spark signals. cheap in price, and are very efficient for er or "tickler" coil which transmits the After the signal has been brought in to this purpose, as most of the tuning on plate oscillations back to the grid circuit maximum audibility the coupling between set "A" is done by inductance, while with giving the "regenerative" effect. This coil L2 a nd L3 is closed to such a point as to set "B" this capacity is very well adaptable may be constructed along different lines, amp ify the signal without destroying its to wave lengths of 200 -2,500 meters, when but a very efficient one may be made by note. With a.' little practise excellent re- used in connection with the usual small winding a cardboard tube 6 inches long and sults, and really marvelous amplification can loose coupler. five inches in diameter full with No. 20 be obtained with this outfit. The inductances of set "A" are made up D.C.C. The coupling may be accomplished With an outfit of this kind, used in con- as follows Ll is the primary loading coil, by simply placing this coil inside the second- nection with an antenna 75 feet high and and is 30 inches long, 6 inches in diameter ary loading coil. Care should be taken, 225 feet long composed of four wires, both and wound up to within two inches of each however, that the direction of winding is Nauen and Eilvese, the German high -pow- end with No. 20 D.C.C. magnet wire. Ten such that it will not buck, instead of assist, ered stations, have been copied thruout the taps are taken off at even intervals along the oscillations of the grid circuit. This (Continued on page 617) 576 THE ELECTRICAL EXPERIMENTER December, 1916 THE ZN5TRUQTR J t I c3 C:=3r c=c=

A Home -made Lathe for the Amateur By Alfonso Bolognesi THE drawings of the lathe here pre- tened with double pointed staples. On the screwing in the middle of the 7 -inch sented show clearly how all the vari- outside, the taut is screwed on as tight as wide board, a piece of iron 4 inches wide ous parts, including the base, are put possible, making the axle quite solid. and 1/16 inch thick, see Fig. A (m), the together and properly aligned. Against the nail on the inside place a piece whole length of the bed or 28 inches long. Make the base of the left end of the of wood with a hole larger than the pipe. On both sides of this iron nail a strip of lathe twice as thick by nailing together This is to serve as a large washer. Now, wood 1% inches wide and % inch thick two of the 3 -inch wide pieces as shown next to this piece of wood place two or (n). On each of these strips fasten a in the drawing, so that it can support the three iron washers and then the wheel is piece of iron 1 inch wide, 1/16 inch thick weight and strain of the large wheel. Do ready to be put on. Next to the wheel and 28 inches long (see o). Fasten these the same with the axle of the pedal. put two or three more washers and lastly strips so that there will be 3 inches be- For the axle of the large wheel and the pin. tween the two and 3 inch from the out- pedal use an iron pipe. At both ends of Make the large and small wheels by side edge of the strip of wood to the out- the pedal's axle bore a hole and pass screwing together two boards, one having side end of the strip of iron, Fig. A. through it a large nail. Fasten this nail the grain in one direction and the other The tailstock is made by bending a piece of iron 10 inches long, 2 inches wide and Y8 inch thick, at right angles, at a point 6% inches B- from one end. (See piece of -A- iron 1, Fig. A.) One inch from the end of the longer piece of the bent iron bore a ç hole (k), large enough to ais .Shoff bearing make the thread for the screw 6.7 with the handle (p). The How pedo/ is fastened thread for p can be made out n i of any piece of the right size ....,_.NOUN n to pipe /tow /in Xs fastened iron, if an ordinary bolt can- l t not be found long enough. In ii..:a...A sattia....t outside of hole the center of the shorter arm of too/rest of the bent iron, another hole - Port is bored large enough so that - C- the thread for bolt s can be 1 f, made. This shorter arm is sf/(7f ixn v-i% next bolted on a piece of hardwood 4 inches long, 3 ill -! inches wide and 1 inch thick 111, (see g). The heads of the Tai/stacta Bed bolts are countersunk into the bottom of the piece of wood. The hole for the bolt s is continued through the wood. On the bottom of this piece of wood (g) a piece of iron 4 inches long, 4 inches wide and 1/16 inch thick (see t) is screwed on by four screws. -D The hole of the bolt s is continued through this iron and with a little care the thread can also be made, so that when the bolt s is screwed down it not only holds the tailstock ,,..L.4.20" firmly wherever desired, but Detoi/ too/ rest makes the latter a whole piece of (drawing together the 1 inch thick iron and 1/16 inch thick iron). The screw with the The Simple Parts Making Up the Amateur's Lathe Described Herewith. It Will Prove Very Useful in Winding Up handle (p) carries a nut so as Coils and Magnets, Building Small Armatures and Light Hand Turning. to prevent it from becoming loose once tightened. By sol- by a pin, so that the pipe cannot turn board with its grain perpendicular to the dering a washer to the tail- center it pre- around and the nail thus fall out. It is grain of the first. This gives the wheels vents the point from going too deeply into better to make the distance between the a 2 -inch thickness. Near the circumfer- the wood. two holes a little less so that the ends of ence of the larger wheel, nail a heavy Make the tool rest in the following man- the lathe will be pulled together, thereby piece of iron rather flat, like a flat iron ner : First by cutting out of the middle of making it firmer; a base strip 1x8 inches wheel so as to give the wheel greater in- a strip of iron 28 inches long, 2 inches at X will strengthen the frame. Use a ertia. The hole in the large wheel where wide and 1/16 inch thick, a 24 -inch slot pipe for the axle of the large, wheel, hav- the bolt (to which the rod connecting the IA inch wide (Fig. C -f). Screw this on ing a thread at one end for a nut. The pedals) is fastened should be 3 inches to a board placed on the front side of the hole through the three pieces of boards from the center of the wheel and a little bed. Then cut a strip of iron (Fig. D -y), where the axle is fastened should be made to the right of a vertical line passing 5 inches long, having the same width and as exact as possible. Bore in the pipe on through the center, when the weight is at thickness as the previous piece and at each the inside (of the lathe) right next to the bottom as is shown in the drawing of end bore a hole, these holes being large the boards a hole and pass through it the right end. enough for an ordinary bolt. After pass- a large nail or pin. This nail is also fas- Make the bed of the lathe, first by ing the bolt through one end, fasten it to i

December, 1916 THE ELECTRICAL EXPERIMENTER 577 the first long piece (y). Through the is connected with the large one by a leather one direction are clipped off, while those other hole pass another bolt and fasten it belt, should be fastened to its axle by a half loops of opposite polarity are allowed to a piece of iron having one end bent (see pin as shown in F. to pass. The result is similar to that shown r). Through any point where it is bent Where the rod or pipe has to turn in in Fig. 1, excepting that with a single cell rectifier, only one -half the energy in the alternating cu-rent is made available in the form of direct current with which to charge a storage battery or other device. The best fo-m of rectifier to realize high efficiency is the one having three electrodes, or better still, a rectifier composed of four individual, aluminum -lead cells, as outlined in Fig. 3. The arrows clearly elucidate just how the current passes through the circuit at different intervals. The full -line arrow indicates the passage of current for one -half cycle, and the dotted line arrow the passage of current through the rectifier cells and direct current apparatus for the second half cycle. An oscillogram curve from such a rectifier will resemble that reproduced at Fig. 1, i. e., the pulses of current will be close together; or in other words, both halves of the alternating current cycle have been rectified. Thus the most efficient type of rectifier is that just described. The usual capacity of a small, glass jar rectifier unit, is about 1% amperes. However, if four such cells are hooked up as at Fig. 3, about three amperes direct cnrrent may be realized The Completed Lathe. It Is Designed to Be Operated by Foot Power, but Can Be Readily Belted 110 60 -cycle A. Up to a Motor or Engine. About yg to ti. P. Will Drive It Nicely for Ordinary Work. when -volt, C. supplies the h circuit. A suitable resistance such as lamp pass another bolt and fasten a piece of the wood, make the hole a little larger and bank, or water rheostat, etc., is invariably iron 5 inches wide having the shape of a insert a piece of tin or better brass pipe. requred in series with the alternating cur- "T" with a hole near the base where it is Cut the ends of the tin and nail them to rent mains to control the current passing. fastened on (see q). This tool rest can the wood as shown in F. Such rectifiers have been built for charg- either be lowered, moved in one direction It is a good plan to fasten the lathe to ing storàge batteries in quite large sizes. or another and the last piece (q) upon the floor, especially if it is run by a small The greater the area and number of plates, which the tool rests, can be placed at any motor / to 1/6 horse-power, which is the greater the direct current available and angle desired. The piece r can be omitted very desirable. vice versa; about 10 amperes per square by making y longer and bent at one end. foot of active electrode surface is usually For the pedal see drawing B. Bend two The base of an old sewing machine can be very well used for allowed in designing them. In some de- strips of iron into a semi -circle shape the base of the lathe. signs a compact oup of plates is used, and fasten them on to the wood of the In that case the bed could not rest on the the lead (or iron plates being staggered pedal. Where the pedal rests on the pipe sewing machine but would have to be in between aluminum ones, with about Vs" insert a piece of tin. raised, since sewing machines as a rule are between adjacent surfaces for the elec- The small wheel (see Fig. F -u) which rather low. trolite. An X -ray machine is built, employing a rectifier of this type, in which OPERATING HINTS FOR as possible. After this preparation has been applied it requires five ELECTRICIANS. to seven hours to Zero /irre of HOT BEARINGS can generally be dry. fbieokó/, traced to the following causes: excessive Contributed by DAVID KARRON. belt tension, failure of oil rings to revolve with the shaft, rough bearing surfaces, bent ELECTROLYTIC RECTIFIERS AND shaft, poor grade of and too little oil, also HOW THEY WORK In While many experimenters utilize electro- end -thrust due to improper levelling. lytic rectifiers in their daily work, the AAA)J case of hot bearings apply heavy lubricants 2rri//oyvcrn of rec/ifiPd rio V. 6o Cycle AC theory upon which they operate is not al- !or e and if necessary shut down the machine, ways clearly ce//rec//frer if understood. fiy.1 keeping the armature running slowly, At Fig. 1, an oscillographic curve is giv- possible, to prevent sticking. en, showing how half waves or loops of ToACcircoit + COMMUTATORS at a TURNING 1 Anode ofA/um alternating current are rectified or swung. speed of 500 to 600 feet per minute will in a common direction with regard to po- be found to give the best results. A dia- larity and the (left to right) time axis. In TLead Ro/bode mond point tool, set with its cutting face other words, if every other loop of current, at right angles, gives the smoothest sur- as shown in Fig. 1, was drawn on the up- face. Finish with fine sand paper. per side of the time axis or zero line of Po%o! Lbíf- TO CUT OUT A DAMAGED ARMA- potential, then we would have the original Siry/e Ce// Connec/ioru TURE COIL disconnect the coil from the alternating current wave -form as before Fiy. 2 commutator and after cutting off the leads rectification. T I b.O.Curoi/ I t insulate the exposed ends with tape ; then At Fig. 2, there is shown schematically connect the commutator bars corresponding the action occurring in the single aluminum - r .4 the leads from the defective coil, by lead electrolytic rectifier cell. These cells to - - - -Z means of a piece of wire about the size of casually contain a saturated solution of bi- the old coil wire. This piece of wire is carbonate of soda. About the best electro- +4 commonly known as a juniper. lyte ever discovered for use in such recti- w.- OCAp,azrnÆcr, Contributed by fiers is one of ammonium phosphate; al- FREDERICK A. GROHSMEYER. though a solution of sodium phosphate is very efficacious for this purpose. When CEMENTING BRASS TO A. C. is applied to a circuit such as that PORCELAIN. shown at Fig. 2, the rectifier cell acts in 4 Ce// Comet/ions Use thoroughly dry litharge and .pure such a manner as to allow the current to L-Leodp/ok/io/LiodeJ A- A/umiaum,cdokronadel glycerine. To avoid trouble see that no pass in one direction only, viz, from the P793 water is in the glycerine or the litharge lead cathode to the aluminum anode. When the reverses and from Showing the Various Actions Taking Place in the damp. If the litharge or glycerine contains current tries to pass Circuits of an Electrolytic Rectifier. water it should be carefully dried at a low the aluminum to the lead, through the so- temperature and the glycerine heated over lution in the cell, it cannot do so, owing to case 5 K.W. of A. C. is taken in at 110 a slow flame until the water is driven off. a film of finely divided gas particles which volts potential and after being rectified The litharge and glycerine should then be congregate on the aluminum electrode; and transformed, it issues at 80,000 volts thoroughly mixed, using as little glycerine, thus the half waves or loops of current in ( unidirectional) direct current. S78 THE ELECTRICAL EXPERIMENTER December, 1916

used in telephone boxes for operating the A "Switchless," Portable Battery Lamp bell. One end of the core of each magnet THE illustrations herewith serve to half inch in diameter, is now bored one is drilled and tapped for a machine screw show the details of construction for inch from the second. A glass tube J is of standard size. Take a machine screw a unique portable battery lamp requir- also to be inserted in this with the ends of about one inch length and cut the head ing no switch to throw the lamp in or out. bent as shown in the illustration. This is off ; next get a strip of brass 3 inches long, done to permit the gas generated by the / inch wide, and % inch thick. Bend this battery to escape through the tube when it strip at right angles 3 inch from the end. is in use. Drill a 5/32 inch hole % inch from the long The next, and perhaps the most impor- end of the strip; on the short end of the tant step, to be taken in the construction strip drill two holes for fastening the strip of the portable battery lamp, is to seal up to the case. the battery jar so as to make it absolutely Insert the machine screw about half its acid -proof. To prevent the acid from length into one of the magnets then slip leaking out of the jar the cracks can be the strip of brass, just described, over the filled up by applying a thin coat of molten screw and screw the other magnet down on top of this. This will be the primary of pitch or asphalt around the inside walls in of the jar, as indicated by the heavy black the transformer, and should be mounted the bottom of a cigar box. (Fig. 1 shows line. This can be done very well by melt- de- ing a few pounds of asphalt in a kettle the primary of transformer as just and the scribed.) It is preferable to make the mag- pouring a small quantity through net cores of soft iron wire. rubber tube holes at A, tilting the whole Coni.ect the two magnets in series and case so that it will run into all the corners; fasten the two remaining wires to binding then permit it to cool. Additional molten posts in the end of the cigar box. tar is added until every crevice and sur- The secondary of the transformer is even face of the interior is thoroughly coated more simple in construction : with the insulating and acid -proof ma- Take a strip of stiff writing paper and terial. The battery plates consist of a car- wrap it around one of the magnets making bon and zinc electrode, each measuring will A Wet -Battery Portable Lamp Which Is Lighted a tube about / inch in thickness that by Placing the Case in the Position Shown. 6x3x3/16 inches. On each lug of the plates fit flush over the flange at the ends of the To Open the Lamp Circuit Turn it Over on Its a hole is drilled large enough to permit Side. magnet; dip this tube in paraffine to stif- an 8 -32 binding post screw to pass as fen it. Then make two cardboard rings This result is obtained by employing a spe- shown. Now by lifting the lid of the outer that will fit snugly over the tube just made, cially designed battery jar so that the elec- case sufficient insulating compound is and place these rings about PA inches apart trolyte can act upon the electrodes only, poured on top of the plates and over the and dip the whole in paraffine to steady whenever the lamp is placed in a certain binding posts to completely cover same. them. (See Fig. 2:) position so as to be lighted. It must be understood that one of the The first thing to be considered is the battery jar sides is not to be secured in container, which is preferably made en- place until the plates are first put into posi- tirely of 3 -inch oak or white wood. Each tion. In order to produce a complete joint side, which measures 9x9 inches square, when putting this side in place, it should be must be thoroughly sandpapered, and put coated with the pitch while exposed and together with glue and flat -head wood warmed when closed. .'VliliuVluIVIIIIIU11IÍ IIIIIIIIIIIINInLIÍIÌIIaull,.. screws. About four screws should be used The electrolyte for the battery consists and these can be either of brass or iron of a mixture of one part of potassium bichromate to three parts of concentrated although the former produce a much neat- r;L:Xt=SX3g7fIRVIMSIIIII er job in the end. sulfuric acid and ten parts of water. In The container consists of eight strips of order to fill the bottom chamber up to white wood. Below are the dimensions of the height of the electrodes a sufficient each of the various pieces: amount of this solution is used, by pour - B -7 "x7 "x /" ing through hole M, closed by stopper R. C-7 "x4 "x /" The lighting unit consists of a 2 volt incan- D-7 "x31/2"x 1/2" descent electric lamp enclosed in a metallic E -7 "x7 "x /" reflector H, the opening of which is closed F "x3 "x with a condensing lens, The dimensions -7 /" and the G- 7'x3 1/2"x 1/2" of this is subject to /four choice The two sides are of the same size, and size of the hole in the frame depends of course upon the size of the reflector. are to be cut to the shape of the jar when f You Have a Pair of 80 or 100 Ohm Electro- completely assembled. The corners must In order to make contact with the central Magnets Lying Around You Can Readily Con- terminal of the lamp (see illustration) a struct an A. C. Transformer for Experimental be very carefully glued with a liquid glue Work. and for the purpose of keeping the parts short brass or copper strip I is fastened in substantial position, h -inch flat head as shown. The other connection is Next procure 30 feet of No. 24 B. &S. Two holes are made from the reflector. The connections gauge copper, cotton -covered magnet wire, iron screws are used. In bored in cover C, the distance between are made with flexible conductors. or a size as near that as possible, and wind them being one inch, and that between order to light the lamp the position of the it all evenly in the space between the two the inner hole and the end of the case container must be such that the solution rings. This completed constitutes the sec- also being one inch, as indicated in illus- covers the entire surface of the electrodes ondary of the transformer which should be as shown in the diagram. When the light slipped over the electro- magnet and the two is to be extinguished all that is necessary leads of the secondary winding made fast /fo /e for bind//y is to turn the cabinet on its side S in such to two binding posts placed in the top of post a manner as to cause the acid to enter the the cigar box. upper compartment, thus freeing the plates The voltage of this transformer may be from the solution. doubled by making another secondary simi- This is the way in which the lamp can lar to the one just described and placing it Shape of carbon and be lighted and extinguished without a on the other magnet in the same manner switch, at the same time preventing the and fastening its leads to two more binding zinc plate zinc plates from being eaten away by the posts in the top of the box, thus making two acid when it is not in use. separate secondary outlets ; and the two 6' secondaries may be connected in series to A SIMPLE STEP -DOWN double the voltage. (Fig. 3 shows the TRANSFORMER. completed transformer and connections.) If these instructions are followed a serv- Showing Shape of Zinc and Carbon Plates Used A step -down transformer for reducing 110 in "Switchiess" Battery Lamp. volt A.C. Current where a low voltage is iceable experimental transformer can be required for experimental purposes, may built at a very small cost. The writer is tration. Two pieces of soft rubber tubing, be made at a low cost in the following man- using a similar one now which he made A (old rubber hose), each one inch long, ner: and it is giving excellent results. are to be inserted snugly into the holes Procure a pair of high resistance (about Contributed by of the cover. A third hole, about one- 80 ohms) electromagnets, similar to those WILLIAM P. McWHORTER. December, 1916 THE ELECTRICAL EXPERIMENTER 579

AN ADJUSTABLE FIXED CON- dium bisulphate one part, and water twenty not be found on the slide wire. The wire DENSER parts. should be wound non -inductively, either by Many of the prominent wireless com- Nickel anodes are used in the bath to winding it double, or reversing the direc- panies are now listing a fixed condenser maintain the strength and great care must tion when half the wire is on the spool. which may be adjusted to variable capaci- be taken to have the bath perfectly balanced, Fig. 2 gives the dimensions for the spool. ties. The following described condenser that is, not too acid nor too alkaline. The ends of the coil are connected to posts is adjustable to a number of capacities and To test this, have handy some blue -and- B, and B,. Fig. 3 gives the dimensions for the tem- -4 Tm/ó// snob perature coil frame X. This has about twenty-five holes drilled in the hard rubber end pieces. No. 40 single cotton -coy- Rd/ed 'ered copper wire is run back and forth between the end pieces, through the holes. Rai/ from /his Bross rod To protect the wires, the coil is encased in edge /Prop in vox paper a brass tube, having a number of holes Cono' cose drilled in it. This allows the air in the tube to change in accordance with the air 111111111111111111111111111111111 in the room. Flexible leads are brought from the coil to the bridge, long enough ,4ssunb/y IIIIII for tf.e work to which the instrument is to be put. The leads run to posts B, and B,. Con/oc/s When connection is made between B. Tinfoil /ermino/s and B and between B, and B the elec- -r bir.dffi/h pire trical thermometer is ready to be connected and so/dered with the receiver T, and the buzzer circuit. --t To test the instrument, the key is pressed, -- t f r-~ Nirif Iermir.n/s j ® and trie response from the buzzer noted in the 'phone. Slider S is then moved until Details and Assembly of an Efficient, Adjustable, Fixed Condenser of the Multiple Switch Type. Can the sound is at a minimum. This shows Be Made in Any Desired Size. that the resistances of L and X, as repre- If the blue paper is dip- sented in the elementary diagram, Fig. 4, in case of necessity may be used in the red litmus paper. of slider place of a variable condenser. ped in acid solution, it will turn red, and have been balanced by means the blue again if placed in an alkaline S. A change in the temperature and a re- Obtain some tinfoil and wax paper. Cut back to of X, how- 3 solution. If the nickel solution is too strong sulting change in the resistance 33 pieces of the wax paper 3 inches by a different adjustment for inches and 8 pieces of 41/2 inches by 41/2 with alkali, a trifle more of the nickel salts ever, requires must be added, so that both the red and the slider. Thus it is that the bridge can inches. Cut 26 pieces of tinfoil 2 inches readings directly. by 3 inches. Make one condenser of 5 blue litmus paper, when dipped in the liquid give temperature If the bath is too The calibration of the apparatus is the pieces of tinfoil and seven of 3 pieces each. will not change color. the laying one alkaline, it will give a disagreeable, yellow- last step. This is done by immersing These units are assembled by is obtained on of the small pieces of wax paper on it, and ish color to the deposit of metal on the coil X in oil. A balance the slide wire, and the temperature of the so on. The tinfoil is to protrude 1/2 inch kathode and if too strong in acid, the metal the will not adhere properly to the kathode, and oil taken by means of a good thermometer. on either side. Then roll condenser is recorded on the scale. from one side, as indicated at sketch A. will strip, peel or blister off. Then the reading Several readings are taken in a similar This rolling has two advantages : first, com- Contributed by WILLIAM WILLIAMS. manner with the oil at different tempera- pactness; second, on account of the thick- readings can be readily ness of tinfoil presented it is easy to tures. Intermediate condenser and then laid off. solder. Bind the rolled HOW TO BUILD AN ELECTRICAL Aside from the enjoyment that an ex- solder the wire to one of the tinfoil lugs. THERMOMETER. in building apparatus, the condenser in one of the perimenter takes Next wrap The operation of the resistance thermom- there are several practical applications for large pieces of wax paper, as indicated at eter depends upon the change in resist- of the electrical lugs unwrapped. this instrument. By means Fig. B, leaving one of the ance of a conductor with a change in tem- thermometer temperatures can be read at Then bind the unwrapped lugs together perature. The ratio of resistance to tem- considerable distances from the room under with a wire and solder a lead to them. perature is constant for ordinary atmos- for suitable test. By substituting a galvanometer The next problem is to build a pheric temperatures, so that it is not at all the telephone receiver, and a steady current switch. The blade is of spring sheet brass, difficult to calibrate the resistance of a con- for the buzzer circuit, a slight change in cut as shown at D. A few suggestive di- ductor in terms of temperature. In this ap- room, the the temperature of a heat -treating mensions are given, but the size of paratus, a movable coil, wound with fine drying racks or incubator can be detected switch will depend upon the contacts used. copper wire, is changed in resistance by the This switch is soldered to the bottom of a atmosphere. The coils of the bridge, how- square brass tube as shown. A battery ter- ever, are wound with manganin wire, which minal such as used on the positive elec- has a very constant temperature coefficient. trode of the Ever -ready type of dry cell is The base of the electrical thermometer is soldered to the top of the slider tube. A 31/2 feet long by eight inches wide. On á1-- r-d'{:- round "Perkins" sn..p switch knob is then this are mounted the six binding posts, B screwed on and the sliding element is com- B B B., B B,, the known resistance R, fg 2 plete. This is shown at Fig. E. The sta- the slide wire and the slider, S, which tionary slider element is a 1/4x1/1-inch brass indicates the temperature on the scale. For Scale J/ide iwel rod. the slide wire and known resistance, num- C A wooden case is then built of the cor- ber 30 S.C.C. manganin wire is used. The rect size to contain all the condenser units. slide wire is fastened beneath the binding Suitable binding posts and contacts are post B then under the brass clamp C, to the mounted on the cabinet and the slider rod other clamp at the right, and finally to bind- is mounted on wooden blocks, as indicated ing post Be. Parallel to the wire a square in the assembled view. brass rod is arranged, one end of which is iMMO '11111 111.11,111 A condenser such as that described has connected to post B,. The slider should so many capacities that it may be used in have a rather sharp contact against the 9uzzer emergency as a variable condenser substi- wire to give the most accurate reading. A tute. While it does not have the advantage scale of cardboard or celluloid is fastened fis' ál fne co,o,oer wires 'X of air dielectric, it will serve the purpose at the opposite side of the wire. This scale Zf/.'o%s very well. The hook -up is shown at Fig. is to be calibrated to give Centigrade or F for the uninitiated. Contributed by Fahrenheit readings. RAYMOND SUTCLIFFE About fifteen feet of number 24 man - ganin wire are required for the known re- PLATING HINTS. sistance R. However, the resistance of the The usual nickel -plating solution is com- different conductors may vary slightly, so Parts and Assembled View of Electrical Then. posed of double nickel- ammonium sulphate that the wire should not be fastened per- mometer. three parts, ammonium carbonate three manently until the bridge is completed, and parts, and water one hundred parts. An- the circuits tested. Otherwise, the resist- by an alarm circuit on the galvanometer. other good formula is composed of nickel ance of the spool might be such that a bal- Where the temperature coil is quite far sulphate, nitrate, or chloride, one part; so- ance with the unknown resistance would away the leads should be heavy. THE ELECTRICAL EXPERIMENTER December, 1916

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

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 A SOUNDING BOARD RHEOSTAT WITH PRECISION A QUICKLY CONSTRUCTED MICROPHONE. ADJUSTMENT BATTERY GAGE. The microphone here shown is twice as The accompanying illustration, I think, I submit herewith a plan for a battery efficient, I believe, when properly con- is self explanatory, but for those readers gauge which, while not giving the exact structed, compared to the ordinary type, as who care to make this rheostat and do not volts or amperes will roughly indicate the it employs two sounding boards instead of quite grasp the idea, I will go into a little amount of energy left in a cell. The cell the customary single one. The wooden detail on it. base acts as one diaphragm and the sound- Procure the following material, (size ing board, 1, as the other. to suit constructor) : one piece' threaded The diaphragm, 1, was made from the brass rod or a large brass machine screw, side of an egg -box cut down to measure one piece fiber or hard rubber rod, one arrc(rim six inches square. It was fastened to the typewriter knob, four screws, two pieces wooden upright, 2, by a brass rod, 5/32 of brass for uprights, one piece of brass of an inch in diameter and four lock -nuts, for yoke, one piece of fiber or hard rubber for opposite yoke, shown in the drawing at 3. The upright, two small pieces of 2, was fastened to the base, 4, by means leather or flat rubber band, onke piece of of a wood -screw and wood for base, two binding posts and a glue. piece of resistance wire. A piece of carbon, 5, which may be obtained from On each end of the brass and fiber rods an old dry cell, was cut to glue the rubber band or leather strip. This 1% inches long. A small, conical indenta- is to make the brass rod revolve when the A Battery Gage that is simplicity Itself. The tion was drilled into this piece about A Further Out the NN eight Is, the Stronger the fiber rod is turned (by friction). Solder Battery of an inch from the top. The second piece one end of wire to brass rod and wind rod Exciting the Magnet. of carbon, 6, which was obtained from a full between the threads, leaving enough lead pencil, should is connected to two binding posts and the be about % of an inch to connect to the brass screw in typewriter current goes through in diameter and about 1% inches in length, the coils which pulls with 'both down the armature. The weight can then ends pointed as per illustration. Resistance wire Threodedbress Le Piece 7 is from Bross fibre adjusted until the coils will no longer cut the piece left over in pull down the armature. making rod, 5, and The reading can is fastened to the brass then be taken from rod, 8, by means of a threaded Bross the scale. hole as in- Contributed by J. L. GLATHART. dicated. This rod, 8, was fastened to the diaphragm by means of a small block of CUTTING GOLD LEAF. wood, 9, glued to it, having a hole drilled Experimenters in the domain of static through the center. Into the hole the rod Rubber bond electricity frequently have occasion to cut was inserted, glued and held by a small narrow strips of gold, silver, or aluminum set screw. The battery from which the foil for use in numerous experiments and carbon was obtained also furnished the ,1iiiiiiiiiliiiiiiiiiii; in the construction of detecting and meas- binding posts-10 and 12. Connections uring instruments. Very few of the leaves were made by attaching a wire from brass are obtained without kinks and notches. rod, 8, running it down the upright to The difficulty can be overcome in a binding post, 10, while the carbon post, 5, very simple manner. Piace the leaf be- was connected with binding post, 12. With tween two pieces of smooth writing paper the addition of four small feet at the cor- and cut paper and leaf together with a very ners, shown at 11, in the drawing, and a sharp pair of scissors. As the metal gen- coat of shellac the instrument was ready erally adheres to the cut edges of the paper for use. A Finely Adjustable Rheostat in which the Wire there will still be a difficulty in separating Is Wound On or Off a Threaded Metal Cylinder it unless the following With the microphone described here- from a Fiber One. simple expedient is with, connected with an ordinary 75 ohm adopted. Lay the strips on a warm flat telephone receiver, and three batteries and knob. The fiber yoke must be on same side surface and cover with a piece of writing as typewriter knob as this prevents short- paper that has been well warmed before c cuiting the wire. Be sure to have the a fire. Hold this at one side and pass one screw of typewriter knob go through the hand lightly across the paper, thus giving brass upright and fit snug as this corn- it a small electric charge. Upon lifting the pletes the connection to binding -post. paper the foil will be found adhering to I think the rest will be clear from the it, and can be removed without difficulty illustration. Turning the knob to right, upon cooling. winds the resistance wire on the fiber rod, thus increasing the resistance of the rheo- INK POWDER. stat, etc. You can see at a glance what a A good ink powder to be thinned with fine adjustment can be obtained from this water can be made from the following: instrument, finer than any rheostat ordi- Malachite Green Crystals, one part; Fuch- narily made. It's a classy little instrument sine, one part; Lump Gum Arabic, one part if the maker will have a little patience in The Gum Arabic should be partly pul- building it. verized. Contributed by JAMES G. FITCHETT. METAL POLISH. Fusorial Earth, % lb. ; Paraffin Wax,. ness and clearness. 1 oz. ; Lubricating Oil, 3 oz. ; Oelic Acid,. Contributed by LEN K. WRIGHT. oz. ; Oil of Mirbane, ?/ dram. Melt the Experimental Microphone Capable of Being [This design provides plenty of Made Extremely Sensitive. Utilizes a Sound De- oppor- Paraffin with the Lubricating Oil and work tecting Diaphragm Made of Wood. tunity for experiment and the board, r, in the powdered Fusorial Earth. Then add. may and has been made quite thick and the Oelic Acid and mix thoroughly. Last- placed in a room, speech from any part of also larger in some comriercial designs. - ly add the Oil of Mirbane. the room was heard with startling loud- Ed. ] Contributed by MERLE NANTZ. December, 1916 THE ELECTRICAL EXPERIMENTER 581

A CARBON ROD RHEOSTAT. with soft solder. Next make a box meas- said that this alloy can be drawn, wrought The boy who has a little time can make uring 8 inches wide and 6 inches deep. and soldered very much like gold, and that a rheostat at very small expense to regu- This will protect the carbons and hold the it also takes and retains a gold polish. It late his small toy electric motor. The rhe- cover A. Connect a wire from the battery is worth 25 cents a pound. ostat here described is easy to make and to the terminal E, then connect the other well worth the effort. Its capacity can be terminal F to the board A to the motor, SIMPLE STATIC MACHINE and next the battery to the motor. The SPINDLE. motor will run fastest when the lever G is The upper spind.e for a high -speed stat- on the carbon H and slowest when on carbon L. Contributed by ELMER YEACK. HOME -MADE TESTING CLIPS. A simple testing clip can be made from a strip of phosphor-bronze No. 22 B. & S. gauge, by cutting off a length 4%" and. A" wide. The slots are cut the same on both ends as shown in the development sketch. After doing this, bend as in the upper

Oro' , r/o f 1 o Gle tested How to Make Effective Belt Pulleys for Static Cu/ Vol os shoArr, Machines from Common Thread Spools. The Experimenter Will Find this Carbon Rod Rheostat Extremely Serviceable. is induction machine like the Whimshurst ELD can be very easily made by sawing or cut- enlarged by increasing the number of car- of an ordinary thread ¢1" ting off the ends bons, but for the average small motor, six spool and then gluing them together as discarded arc lamp carbons will generally shown in Fig. 2. If a flat belt is to be suffice. /Ike so/deredfo c/%o Ee used instead of .a cord then the spindle First procure a piece of clear pine or should be similar to Fig. 3. other soft wood measuring 8 inches long, Here's a Test -clip Anyone Can Make from a Contributed by JOHN T. DWYER. 6 inches wide and ji inch thick; this is Strip of Brass or Bronze. shown at A. Draw a line parallel with LOCATING A GROUND BY the ends, one inch from the top of A and illustration of Fig., and solder a wire on VOLTMETER. mark a point B, to set your compass on. the clip. a ground can be deter- with The distance to Now with the compass points set 4 inches When the clip is pressed together mined only approximately by means of a apart draw part of a circle. Bore six holes the fingers the wire is disconnected. When when the resis- in the voltmeter, and then only 1% inches apart on this line. Bore the released it will hold the wire firmly tance at the ground is negligible compared holes the size of the carbon you can pro- jaw, making a good connection. with the resistance of the bad wire from cure. Contributed by FRANK HARAZIM. the testing end to the ground. To estimate For the carbons you can use those found the distance to -he ground, connect the in batteries or obtain a few from the lamp - TO CLEAN BRASSWARE. Mix one ounce of oxalic acid, six ounces voltmeter across the terminals of a suitable man when he removes the carbons from of battery and call the reading d. Then connect the street arc lights. Cut them about 5 of rotten stone, in a powder, one ounce sweet oil and enough water to make a the same battery and voltmeter in series inches long, for that length is sufficient. with the line to be tested and the ground, insert in the holes you paste. Apply a small amount and rub dry Now the carbons is much better than thus forming a circuit through the battery, have bored, so that about inch or 3/ with a flannel. This / most of the polishes, as it will not cor- voltmeter, line, and ground. Let the volt- inch projects above the top of the box A. meter reading be dl. Then, if r is the re- Turn the piece over and pour melted seal- rode the brass as do polishes that contain of nitric or other acids. sistance of the voltmeter, the resistance ing wax or paraffin around the holes to the circuit is hold the carbons in place. Next obtain a CANDELABRA ADAPTER. piece of brass G, about 4 inches long and To make an adapter, for reducing the (a) R =r(d -1) inch wide and drill a 5/32 hole in it. Edison -base down to a miniature or can- Then secure a % inch bolt and nut and delabra size, procure an old burned -out This is the same formula used in deter- attach it on the board as shown. On the Edison -base lamp and break the globe, mining the insulation resistance of a line. other end mount a small knob from an old leaving only the brass base. Since the line is grounded at some point, kettle lid. Two binding posts from old From a miniature or candelabra Christ- R is only larger than r by the resistance of batteries are all right. Put these on each mas tree socket, take out the brass thread- the line, earth return, and ground contacts. corner of the board at E and F. Connect ed part. That is the vital part of the Hence, the resistance x to the ground is the brass blade G to E with No. 16 in- socket. It will be found that the Edison- R-r and is given by the formula: sulated wire and use similar wire to con- base will have the old wire still soldered nect H with F. H is the carbon under- to it ; leave it so, and proceed to solder (b) :: -r(át -z) neath the board. Connect the carbon H with K and so on using the same size wire. Scrape off all the insulation where it is A SUBSTITUTE FOR INSULATING wound around the carbon and solder it CLEATS. In wiring up bells, alarms, etc., the use A SIMPLE RHEOSTAT. makes a very The illustration accompanying this article of common felt gun wads good cleat for the wires. They are used shows a simple rheostat which the writer wire is placed made very cheaply from a door spring, four as illustrated. Tite insulated binding posts and a slider with rod to fit. The door spring can be of any desired Yiílifllfll Simp e Manner of Convert'ng Miniature Base Lamp to Candelabra Style. the free ends to one of the small sockets. Having done this, fill the large base with mòistened plaster of paris, and sink the small lamp base into the plaster until it is level. Be careful not to break or short - circuit the connectións while doing this. Allow to dry and the adapter is ready for use. A Rheostat Made from A Door Spring and a Contributed by MARSHALL CREE. Using Felt Pads from Shot-gun Shells as "Cleats" Slider. For Wires. length, but the size indicated proved the SUBSTITUTE FOR GOLD. most successful. A close study of the il- A substitute for gold is obtained by com- between two wars and is fastened by two lustration will show how it is made. The bining 94 parts of copper with 6 parts of nails or screws. and adding a little magnesium Contributed by insulation was made from cardboard. antimony ABBOTT. Contributed by MORRIS ZUY. carbonate to increase the weight. It is LEWELLYN 582 7.-- THE ELECTRICAL EXPERIMENTER December, 1916 Experimental Chemistry By Albert W. Wilsdon Seventh Lesson HYDROGEN. The reaction of Nitric Acid [HNO.] and 5. It is used in the laboratory as a reduc- YDROGEN is a colorless, odor- Copper [Cu] will not liberate Hydrogen, ing agent. less and tasteless gas. It is the as can be shown by the equation: Experiment No. 22- lightest of any of the known ele- 3Cu + 8 HNO, = 3 Cu[NO,], + 4H,0 + 2 NO Bend a glass tube as shown by Fig. 33. ments. This gas was discovered Copper Nitric Copper Water Nitrogen by Paracelsus [born near Zurich, Acid Nitrat Monoxid Switzerland, 1493 -died, 1541], a remarkable alchemist and physician, in the Six- This equation shows that all acids will teenth Century by the interaction of acid not react with metals to liberate Hydrogen. and metals. In this case Water [H2O] and Nitrogen pÍlli'ql,, In 1766, Henry Cavendish [born at Nice, Monoxid [NO] was formed in the place 1731 -died 1810], discovered the extreme of Hydrogen. sss levity of inflammable air, which Antoine 2. Hydrogen can also be prepared by the Laurent Lavoisier, the distinguished French reaction of metallic Sodium [Na] or, me- chemist, about 1783 termed Hydrogen, and tallic Potassium [K] on water, the reaction this name it still retains. being: 2Na The discovery of Cavendish led to bal- + 2 H2O 2 NaOH + H, I Sodium Water Sodium Hydrogen loon experiments and projects for aerial [metallic] navigation. Cavendish later discovered Hydroxid that water resulted 2K + 2 H2O = 2 KOH from the union of two Potassium Water Potassium +Hydrogen gases, namely- Oxygen and Hydrogen. [metallic] Hydroxid Occurrence and Distribution. 3. By the electrolysis of water. The UNCOMBINED : -Free hydrogen .is present equation for the liberation of hydrogen by in the gases which escape from volcanoes, the Electrolysis of water is as follows: natural gas openings, and in coal mines. COMBINED :- Combined Hydrogen is Water Hydrogenn + Oxygen abundant Bottles Filled with "Hydrogen Shou d be Kept and widely distributed. It forms Inverted 1 4. By passing steam Owing to its Lightness and Tendency to -9th part by weight, and 2 -3rds parts by over iron filings, the Escape. Lower Figure- Experimenting with a volume, of water. It is also found in reaction being: -Lighted Splint and "Hydrogen." plants and animal tissues, as well as in 3Fe 4 4H2O vegetable matter. It is an essential con- Iron Water F osso,-- + Hydogen [Consult the June, 1916, issue of THE ELEC- stituent of all acids, and when combined Ferric Oxid TRICAL EXPERIMENTER for method of bend- with carbon, forms many gases and liquids 5. By boiling Zinc in Potassium Hy- ing glass tubing.] called hydrocarbons, which are used in the droxid, the reaction being: Set up the apparatus shown by Fig. 33, manufacture of kerosene naphtha, and il- 2 KOH + Zn = KZnO, + 2 H by placing a few pieces of Zinc in the bottle luminating gas. It is also found in carbohy- and partially fill it with water as shown. drates, or many vegetable compounds, as, Properties. Pass the Thistle tube thru the 2 -hole wood, paper, sugar, starch, rubber stopper, being sure etc. When CHEMICAL : -1. Hydrogen unites with that both the combined with nitrogen it forms Ammonia oxygen and many elements directly. Cav- tube and hole are wet, and insert the tube [NH.] ; and when combined with Sulfur, endish showed that Hydrogen burning in with a twisting movement, grasping the tube forms Hydrogen Sulfid [H,S], which is air formed steam [water]. as near the bottom as possible. DO NOT to be found in the free state at many sul- 2. It burns in the air and oxygen with FAIL to take these precautions. Insert the fur springs. almost an invisible, but very hot flame, the delivery tube in the same manner, as shown Relation to Life. heat given off being as much as five times by Fig. 33. Although hydrogen is not poisonous, it its weight of coal. Now, after filling two 8 -ounce bottles will not support. life, or respiration. 3. It has great affinity for Chlorin [Cl] with water as shown by Figs. 28 and 29 November, 1916, issue of THE ELECTRICAL Preparation. forming Hydrochloric acid [HC1] ; with Fluorin [Fl] forms Hydrofluoric Acid EXPERIMENTER], place them under the water Hydrogen, like oxygen, may be prepared in the tray or basin in the same manner from its [HF1] ; with Bromin [Br] forms Hydro - compounds, by any of the follow- bromic acid [HBr]. as described for the collection of oxygen in ing methods : 4. It indirectly forms hydrocarbons. the last installment. 1. By the interaction of a metal with an Place the delivery tube under the receiv- acid. The metals usually 5. It is a strong reducing agent. employed in the 6. It has no affinity for most metals. ing bottle and collect the gas by adding laboratory for this purpose are : Zinc [Zn] ; 7. It is a non -supporter of ordinary com- about 3 c.c. of MCI. to the water thru the or Iron [Fe]. While the acids usually em- bustion. Thistle tube. (Reject the first portion of ployed are : Sulfuric or Hydrochloric in di- the gas.) As the gas is invisible the indi- lute 8. A mixture of Hydrogen and air, ex- solutions. plodes violently cation that the bottle is full is made appar The reaction which takes place when ignited. [Be sure in between performing the experiment of collecting ent by the appearance of bubbles of gas these acids and metals are : as follows this gas by the displacement of water, that around the outside of the receiver. Slip a NO air is allowed to remain in the bottle. glass plate [4 x 4 inches] over the mouth of the filled bottle Thistle, tube PHYSICAL : -1. Hydrogen is without odor, WHILE UNDER color or taste. WATER and remove. Keep in an inverted Delivery tube 2. It is the lightest gas known. One liter position, as shown by Fig. 34, until ready to at S.T.P. weighs approximately 0.09 gram. apply the tests. The reason that the bottle Rubberstopp 3. It is slightly soluble in water. Two is placed in this position, is on account of volumes of hydrogen dissolving in one -hun- tl.a extreme lightness of the gas, which has dred volumes of water. a very strong tendency to rise. If placed 4. It is rapidly diffusible. upright as done with the oxygen in the 5. It can be liquefied and solidified, the previous experiments, it would be likely to escape from liquid being 1 -14th as dense as water, and the receiver. is the lightest liquid known. [Note :-If the reaction is not strong 6. It is not poisonous, but will not sup- enough upon the addition of 3 to 5 c.c. of port life. Hydrochloric acid [HCI], add more acid till the generation Uses of Hydrogen. takes place with fairly rapid intensity. If the action becomes too strong, ff 1. For the Oxy- Hydrogen Blowpipe. add more water, a little at a time, till it de- [See the October, 1916, issue of THE ELEC- How the Apparatus Is Set Up for Producing and creases.] Collecting "Hydrogen." See Experiment No. n. TRICAL EXPERIMENTER for illustrations and Experiment No. 23- 1 descriptions of the apparatus.] Take a receiver filled with Hydrogen, and ZnCI, 2. The low density permits its use in bal- Zu +2 HCl Zinc Chlorid + H, hold it in the left hand, upside down, as ZnSO4 loons. shown by Fig. 34, then apply a lighted splint Zn +H,SO. Zinc Sulfat + H. 3. It is used as an ingredient in the manu- to the mouth, being careful to keep the fin- FeCI facture of illuminating gas. Fe +2 HCI Ferrous Chlorid + H, gers holding the splint, near the side of the FeSO4 4. It is used for high and low tempera- jar, as shown by Fig. 36. Notice precisely Fe +H,SO. Ferrous Sulfat + H, ture thermometers. (Continued on page 62a) December, ii, 1+ THE ELECTRICAL EXPERIMENTER 583

ACID INK ERADICATOR. to form a stiff paste, and work or stir with An ink eradicator quite as good as those a small stick until thoroughly mixed. manufactured is given below: Let this mixture stand for 20 minutes be- Wrirìk1e The article s Add 110 grams of chloride of lime to I fore using. This is important. liter of water; let the solution stand for to be mended should be free from all dirt 24 hours, then strain through fine cloth and grease before applying the cement, and 1 and add to parts acetic acid to each 25 should be perfectly dry. parts of solution. For Mending Holes in Pots, Pans, etc.: - To erase ink, apply with reverse end of Fill the hole with the paste, applying to a penholder, and dry with a blotter. both inside and outside surfaces, allow it to dry or four hours, then fill the vessel REMOVING HARD RUBBER with water, place on the fire and let boil, m_ s SCRAT CHES. the water, wipe dry and let stand ulà pour out To remove scratches from hard rubber in the air for two to six hours longer. If pass a heated soldering copper over a desired, after the cement is thoroughly thickness of paper laid on the surface of hardened, the place may be smoothed up EDITED BYS.GERNSBACK the rubber. with sand paper. For extremely large holes Under this heading we publish every month use- Contributed by FRANK SKINNER. obe mended on a piece ful information in Mechanics, Electricity and place the vessel to Chemistry. We shall be pleased, of course, to HOME-MADE GAS GENERATOR of paper, and fill hole with the paste from have our readers send us any recipes, formulas, the inside. Let tae paper remain until the wrinkles, new ideas etc., useful to the experi- A neat and efficient hydrogen gas gen- menter, which will be duly paid for, upon pub- erator from which a supply of gas is avail- cement is thoroughly hardened, then burn lication, if acceptable. able at any moment, can be very easily off. De not tear off. made of a wide mouth bottle, a test tube, For Mending Marble, Glass and Bric -a- USEFUL GLASS WORKING two (preferably rubber) corks, a glass brac: -Apply the paste to both broken sur- FORMULAS. thistle tube and a wire pinch cock. faces in a thin layer, press closely together The bottom of a test tube is heated and and allow to harden in the air for six to 1. Glass Polishing Paste.-Prepared twelve hours. chalk, 9 oz.; white bole, oz.; jewelers' drawn to a point, the point is then nicked / off with a file leaving a hole large enough Do not omit letting the mixture stand rouge, / oz.; water, 5 oz.; alcohol, 3 oz. minutes mixing with wa- Mix into a paste. To clean and polish win- to loosely admit the lower end of a long for twenty after thistle tube. ter. This is essential for the casein to be- dows or mirrors, moisten a cloth with alco- and amalga- the about The thistle tube and a delivery tube are come thoroughly dissolved hol, place a quantity of paste mated with .remaining ingredients. the size of a bean on the glass and rub placed in a two -hole stopper and inserted the in the test tube. The end of the thistle Ink- Erasing Biotter: -Take an ordinary over the surface with the cloth until dry it and powder is removed. sheet of thick blotting paper and steep several times in a solution .of oxalic potas- 2. To Cut Glass Without a Diamond - sium, a id dry. While the ink spot is still Glass may be cut under water with a strong moist apply the blotter, and the ink will pair of scissors or shears. Mark the part be entirely removed. If the ink is dry that is to be cut away with a heavy black water moisten and apply the blotter. line, then sink it with one hand under Contributed by S. ENGLISH. as deep as you can without interfering with your view of the line and with the other STENCILS FOR CHEMISTRY hand use the scissors to cut away the part STUDENTS. that is not required. All students of chemistry, whether they 3. To Drill Holes in Glass. -Bank the attend a residential school or not, have spot with a wad of putty. Make a hole into undoubtedly often wished for some form the putty down to the glass and of the size of transparent stencil with which they wanted. Into this pour melted lead and the could artistically, yet rapidly draw dia- piece will drop out. grams; and especially sectional diagrams re- 4. To Engrave on Glass.-Apply a thin of the various 3asks, test tubes and coating of wax to the glass with gentle heat. torts used in such work. When cool draw the design on the wax Such stencils have recently been brought with a hard -pointed instrument so it pene- out by an English scientific house, and trates through to the glass. Apply an they are described in a current number of aqueous solution of hydrofluoric acid to the Nature. This excellent set of stencils, several which have been approved and permitted design with a soft brush. Apply taking chemistry times to get deep outlines. Finally wash to be used by students the wax by heat. in English schools and colleges, have been the acid off and remove officially approved by the faculty of the Glass. paint 5. Imitation of Ground -A A Handy Gas Generator Made from Odd Parts University of London and also by the In- for imitating ground glass is made by rub- Found About the Work -shop. dian Education authorities. bing down some zinc oxide with linseed oil Undoubtedly, Instructors in chemistry in on a slab to a thick cream. Apply to the tube should protrude from the test tube high -schools and colleges will be pleased glass thinly and stipple with a stiff brush. to have their students obtain such sten- Proof. about one quarter of an inch. 6. To Make Window Glass Sun - The test tube is then mounted in a large cils, as the examination papers will then Pulverize gum tragacanth and let it dis- lend themselves to a much quicker perusal well single hole stopper and placed into the solve for 24 hours in the white of eggs, neck of a wide mouth bottle. After slip- by the teachers. Moreover, they help the beaten. Lay a coat of this on the window student to keep first -class notes in his brush, let it dry, and you ping a piece of rubber tubing over the de- panes with a soft livery tube, the apparatus is ready for use. data book and not a mixture of harum- will have a coating the rays of the sun can- scarum sketches, which are often so poorly Place lumps of zinc to be acted upon :hey are absolutely unin- not penetrate. by the acid into the test tube as shown. executed that sulphuric acid (4 telligible when referred to at some future Gold -plating Without a Battery. -Crean Now pour the diluted date. the article to be plated with a brush and parts water, 1 part acid) into the thistle ammonia water until it is bright and un- tube until it is full. The acid will soon MAKE A small piece of gold reach the zinc and react with it, giving a HOW TO VOLCANO. tarnished, then take a Take a bowl Dr crock about 6 inches in and dissolve it in four times its volume of steady supply of gas. an amal- rubber tubing with a diameter and fill it up with earth, so that metallic mercury, which forms By closing the it resembles a miniature mountain. Make gam. With a dry cloth rub a little of this pinch cock the pressure of the gas in the article to be plated, then will force the acid up the thistle a hole about / of an inch in diameter and amalgam on the interior 6 deep it a stone in a furnace and heat to tube, the chemical action to stop. inches for the crater. place on causing Fill up with a mixture the beginning of redness. After it cools Contributed by JOSEPH R. MAYER. this crater of po- 3 1 part, clean with a brush and a little cream of tassium chloride parts, sulphur tartar. CEMENT FORMULA. charcoal 1 part, wax 2 parts and sugar 2 Silver- plating Powder. -Chloride of sil- Powdered Casein No. 98-4 ozs. parts. Now light the mixture in the crater. Lime ozs. The result will be a dense smoke, fire com- ver, 3 oz. ; salts of tartar, 6 oz. ; prepared Powdered Slaked -5 Barytes ozs. ing from the crater with lava pouring down chalk, 2 oz. ; common salt, 3 oz. Mix. Dip Powdered -20 a moist cloth in this powder and rub the Mix thoroughly. its sic s. article to be plated. In use pour a little of the powder into Contributed by Contributed by MYLES S. CLOSZ. any convenient vessel, add sufficient water THOS. McCAUSLAND. ENGINEER" ECTOR f$rrtt Ovum of

John fl lillu,m:

He Becomes an Erector Engineer Next an E-

./ Look at Jack in the picture here -and then put yourself in his place! He is now a member of The Gilbert Institute of Erector Engineering-and you can be a member, too, when you own an Erector set. Then when you're a member of the Institute you to add to your fun with Erect have something to look forward to, like Jack -you for all kinds of fun when I w can go in to win the three Erector Engineering Diplomas thing that boys like, and bi and other worth -while rewards. Can't you see yourself win- Vaulter, won many medals ning the First Diploma or Degree of Honor -then the Second learned how to do a lot of ma -then the Third and highest Honor of Erector Master boy myself and know what re Engineer? Maybe you can look as far as Jack does and see I know you fellows don't ca yourself, when you're a little older, as one of the famous that do not require brains of grown -up Master Engineers of our Country, who build great that kind of fun. That's wh. bridges, buildings canals. and to make Erector even fi of the fame, high Honors more Think it over for a minute-think Gilbert Institute of and Rewards you may win -and think of the fun, lots of it, Erector I that you'll be having all the time you're trying! As soon as you become a mei to the Fraternity of Erector E It's Play That Boys Like to go after the three Degrees I started the Gilbert Institute of Erector Toy Engineering go with them. E "The Toy Like Stru Get These Big Advantages HERE'S A DAN: Look at this picture of Erector No. 4 set. I in Erector set of all, because it includes the Erector ele(

hundreds of parts. There are big girders, la . 1. The only actual structural steel toy. 2. The interlocking shafting, corner plates, angle irons. pinions, edged girders (an exclusive patented feature) enable you to build nuts and bolts -in fact, practically all esse square columna. 3. Each piece is stamped accurately out of parts for building all kinds of structures. steel- correct in design and proportion. 4. Most parts for build- The sturdy electric motor is a wonder, a ing strongest and largest models. 5. Builds suspension bridge great fun with it. It is better than many me 21 feet long, capable of supporting a large and heavy boy. 6. The or four times as much. it has four terminals: sturdy electric motor comes with most sets and will lift 200 pounds at a touch of the switch: works quickly and when properly geared. This is a scientifically constructed motor evenly. It will easily lift 200 pounds when p built by an electrical expert. More than a toy. Operates You can build at least a thousand good moc with reversing switch base, control switch, multi- geared motor enables you to make many that operate motor box, etc. 7. Big reenforced steel wheels: grooved You don't have to build only models found r and hubbed for every engineering purpose. 8. Every essen- tion which come with each set. It is easy to in tial engineering part. 9. The three big manuals show of your own. Hundreds of boys have done t over 500 actual mechanical models which have been won valuable prizes. built with the No. 4 set alone. In addition to those See what you can make and win a valuabl illustrated, thousands of other models can be built your chum in with you and build all kinds of 1 depending only on your originality and skill. machinery that you can operate. The more you build with Erector the more to build miniature reproduction of famous en Canal Locks, Brooklyn Bridge and the Eiffel To, Erector sets range in price from $1 up to $1 you lots of fun, while, of course, the larger or and better models. $5,000 Prize Contest Canadian boys, of course, are just as eligible boys of the U. S. A. In fact, boys all over the Get into this Big Prize Contest boys! Go Engineering Honors, and compete in the Big P in to win the splendid First Prize -a dandy, Ark the man in your toy store to show you new, up -to- the -minute Saxon Automobile. Or, will be glad to do it, and to tell you all about it if you are under 12 _years old. go after the ing_-and the size of girders, until you see a a finest little Shetland Pony you ever saw. Erector No. 4. Price $5.00. (Price in Cans Thousands of boys in every section of the U There are a lot of other fine prizes. too It is the dandiest Christmas present you could motorcycles. bicycles, camping outfits and 495- ing the big Erector bridges, elevators, that you others. Make up your mind to win one- and lift steel beams. In fact there's nothing,, and go to it. Mail the coupon in opposite corner for full details. THE À. Ca GILBP

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 584 t Engineer Then a Master Engineer and Finally in Real Life

with the title "Erector Master Engineer," a handsome rolled gold Fraternity Pin -a good salaried position with us during the holiday season -and the finest recommendation which can be written for you to any ausiness house to whom you Toy Engineering may wish to apply for a positior.. START NOW ! I used to be on the lookout Win These Honors and Other Rewards boy. I went in for every- Think of the fun you'll have trying fur these Honors and other Rewards! And remember, you may win one of the prizes in our $5,000 Prize Contest. te World's Champion Pole First Degree -It is quite easy to win this Degree. All too. Join the Erector Engineers, now. Start just as soon as you cant ill track team sports; and you have to do is to send us a photograph of an Erector model There's something to this kind of fun -you may be the fortunate boy ricks. In fact, I was a real you have built, with or without a motor-or of a motor built who will win the biggest prizes and Honors this year. Sys want. with the Erector Electrical Set -or of a building made with nuch about and Brik -tor. Then we will send you a fine Diploma, giving you For "Bricking-in" toys games the title of "Erector Engineer, as a testimonial to your skill. MEN,,iL ill. You soon get tired of Or Steel Structures nvented Erector -and now Second Degree-This Degree is a little harder to win, easy for the boy who has a little steam back of him. Finish up the brick work of your Erector nd more real, I started The but buildings w_th Brik -tor. With these bright red neering: This time you earn not only a Diploma which awards you bricks, the elate ones for roof effects, and the the Degree of "Erector Expert Engineer," but also a handsome white pieces for trimming -not to mention the doors and windows -you can make the build- :r of the Institute and belong button which you can show to your friends as proof of your ings even more like the real thing. nears, you can start at once brains and skill. You can "brick -in ' the walls, chimneys and donor and foundations of your buildings-the towers of the Rewards that Third Degree-Here is the hardest of all Honors to win, your bridges, and the piers. There's a fine but one well worth trying for! Your reward is a Diploma, big book of instructions chock -full of pictures free with each set. See. one of these sets at your toy store and you'll see what fine work you can do with- Brik -tor. Price $5.00. In Canada $7.50. ERECTOR ELECTRICAL SET Be an Electrical Engineer! This is the Electrical Age! In the Erector Electrical Set of Experimental Apparatus together with the illustrated elementary course on Elec- 11101.10 trical Engineering we olfar the most fascinating play- thing for teaching. demonstrating and applying the secrets and principles of electricity that has been gotten out. You learn and play. It is the most fun you ever enjoyed. It contains all parts for bui.ding turai Steel" motors and other apparatus, also for conducting 100 experiments. Price templete, $5.00; in Canada $7.50. Y SET All Boys Know This A WORD TO PARENTS the most popular Toy ERECTOR will give your boy in generous measure, the best kind is motor, as well as of fun. He will learn while he plays. His play will be along the e and small wheels. Of course know that Erector is the steel con- constructive lines alleys, gear wheels. you that build character and prepare him for the world struction toy which enables you to build all kinds of of business. Erector 'toy Enginee -ing will awaken his ambitions Mel engineering it gives him play with an object. You cannot choose a gift that- machinery, bridges, buildings. battleships and hundreds will please him better for Christmas. I you can have of other things. Each set contains the steel parts irs costing three peratea instantly such as are used in actual construction and it's easy aces the current to copy every sort of machine or bridge or building Send For Free Copy of "Erector Tips" aperly geared. out of the real steel girders and other parts Is with this set, and the I want to send you absolutely free, the st like real machinery. November issue of my boys' magazine, "Erector the Manuals of Instruc- Tips." It's full of stories and photographs-all ent some original models Erector offers you a wonderful feast made especially for you. tells what other is with their Erector sets and It of fun. When you own a set, you Erector boys are doing, too -and gives full details prize and Honors, too. Get Boys! have "the best known toy in the about Erector Toy Engineering and the $5,000 utldings as well as all kinds of Prize Contest. I want to present, also, with my world." Not only that, but you become a member, compliments, my big book telling all about my fun you'll have, as you learn free, of the Gilbert Institute of Erector Engineering toys and the things I do for boys. Send for ineering feats like the Panama and have the opportunity of winning fame, honors your free copies of "Erector Tips" and the ver, Aeroplanes. Engines. etc. and other worth -while rewards. Then added to that book now, as the number I can supply is limited 5. Even a small set will give the coupon below to me, after you you can enter the Big Prize Contest and perhaps -just mail ;es enable you to build bigger have filled it in. roe win an automobile, a pony or one of the other 498 for Diploma and Prizes as are fine prizes. world may obtain Erector Toy MAIL THIS . `rize Contest. Thousands of boys will be made happy by receiving The the No. 4 set-or any other sets you may wish. He EREECTOR. TIPS COUPON A. C. Gilbert You can't imagine the many parts -the easy build - Erector Sets for Christmas. It will please them Company, et of Erector. better than any other toy because they know it will 160 Fox Street, ids, $7.50.) of fun that is always new and New Haven, Conn. ted States are building great models with it every day. give them the kind $5000°óo Prize Offer ask for. You and your chums will never tire of build- chock-full of interest. 500 Prize -All fa Please send me, free, the Novena- an run by electric motor, or derricks that swing around ben -s ber issue of your boys' magazine, Be sure to get your set this Christmas. mechanical but can he duplicated with Erector. You - Erector Tips," and your big book, How To Become an Erector Master Engineer. New Conn. NAME ART COMPANY, 160 Fox St., Haven, ADDRESS

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 585 586 THE ELECTRICAL EXPERIMENTER December, 1916

Our Amateur Radio Station Contest is open to all readers, whether subscribers or not. The photos are judged for best arrangement and efficiency of the apparatus. To increase the interest of this department we make it a rule not to publish photos of stations unaccompanied by that of the owner. Dark photos preferred to light toned ones. We pay each month $3.00 prize for the best photo. Make your description brief and use only one side of the sheet. Address the Editor, "With the Amateurs" Dept.

AMATEUR RADIO STATION tector, condenser and a pair of 2,000 ohm RUSSO- JAPANESE WIRELESS. CONTEST. 'phones. Testing of the wireless telegraphic com- Monthly Prize, $3.00. I have heard practically all the high - munication between Ochiishi, Hokkaido, This month's prize- winner. powered commercial radio stations, as well and Petrovsk, Kamchatka, has been suc- LEE MOCICKE, A CHICAGO cessfully carried out, and an agreement has "RADIO-BUG." recently been concluded between the Jap- anese and Russian authorities relating to My wireless station includes the follow- the same. Preparations have been coming: pleted whereby the wireless service will The sending set-a 1 K.W open -core come into actual operation at any time transformer, rotary spark gap with motor which may be agreed upon. The new wire- speed regulator, oil immersed condenser and less communication is, in the meantime, to oscillation transformer. A 1 -inch coil is be employed when the ordinary cable lines also used. between Russia and Japan are interrupted. The sending aerial is 60 feet long by 50 The Russian wireless station affected by feet high and has 4 wires. This aerial is this arrangement is on the peninsula of also used for receiving, together with a Kamchatka, one of the boundaries of the single wire, 175 feet aerial of stranded wire. Sea of Okhotsk. From the southern point A Navy type loose coupler, two variable of Kamchatka a string of islands -the Kur- condensers, loading coils, galena detector, ile islands-runs in a southwesterly direc- variometer and an amplifier of my own de- tion to the most northern island of Japan - sign and construction complete the receiv- Yezo. Here is the first Japanese wireless ing set. C. E. Mielke and His Excellent Radio Station station, at Hokkaido. Between 500 and 600 Amateurs in Chicago come in clear and which Has Picked Up Signals from Far and Near. miles separate Yezo from Kamchatka. 8 AEZ, is heard occasionally; NAR, NAA, Is the smaller ones, along the coast and Great Lakes and have talked to a countless GUY L. BEECH'S RADIO STATION. number of amateurs within quite a large My receiving set here illustrated consists radius. C. E. MIELKE. of a pair of 3,000 ohm Murdock special N.S. Pittsburgh, Pa. 'phones, fixed condenser, loading coil, a ROBERT J. ENGLER TRANSMITS OVER 600 MILES. I hope the description of my station and the pictures accompanying it will be of interest to E. E. readers. I have one aerial forty feet high and forty -five feet long for transmitting and a long aerial, four hundred feet long by sixty high, two wire, for long wave receiving. The entire transmitting set is placed in a closet, so as to reduce the noise and also to get it out of the way. I have rolled up quite a record with this outfit of over 600 miles. It consists of 3 K.W. rotary spark set, operated on 60 cycles A.C. It has a spark frequency of 345 per second. With it I put 2% amperes into my aerial at 200 Guy L. Beech at His Radio Instruments. He metres. Holds a Certificate of Membership in the "Radio Prize Winning Radio Laboratory of Lee Mocicke, The receiving set is so designed that I League of America," Also Government Station Comprising an Efficient 1 K.W. Transmitting am able to receive waves from 200 to 16,000 and Operating Licenses. Set, Together with Effective Receiving Apparatus, meters in length. I Built by Himself. use a circuit similar to that of Mr. McKnight's, but with a number 3,000 meter loose coupler of my own make as well as Great Lake boats and Gulf sta- of changes of my own. and a detector. tions can also be heard. With this set I have copied NAA, NAR, For sending I use a good telegraph key, LEE liOCICKE. NAO, NAJ, NAT, VAN, WGG and WSF. the platinum contacts of which have been Chicago, Ill, I have also picked up POZ, OUI and NBA, replaced by E. I. Co., silver contacts, / including 9NN, 9DB, 9SP and 9RA. K.W. closed core sending transformer, AN AMATEUR WIRELESS ECHO helix, spark gap and condenser. FROM PITTSBURGH. I can receive 1,500 miles and transmit Herewith find picture of the 8 IB radio from 50 to 100 miles. I hold an amateurs' station of Pittsburgh, Pa. second grade operator's license and second The sending outfit consists of a / K.W. grade station license and am a member of closed core transformer, glass plate con- the Radio League of America. My official denser, helix, high speed rotary gap and a call is 9 CL sending key fitted with large silver con- GUY I. BEECH. tacts. The transformer has three varia- Clarinda, Iowa. tions of power and a rheostat controls the speed of the rotary gap. SUCCESSFUL COMMERCIAL RA- on hill Complete Radio Equipment of Robert Engler, DIO TESTS WITH JAPAN. The aerial is situated a overlook- with which He Has Heard "POZ," Germany, ing the Ohio River and is 120 feet long, and Other Distant Stations. The third and final series of tests for supported on two iron poles each 40 feet trans -oceanic radio service between Hono- high. It is of the inverted "L" type with I would like to tell about the many inter- lulu and Japan has just been completed. 4 wires spaced 4/ feet apart. esting messages I have received, but of Telegraphic reports indicate that these tests For receiving I use a long wave loose course this is against the law. are by far the most successful of any so coupler having loading inductances in the ROBERT JOSEF ENGLER. far made. Communication has been main- primary and secondary circuits, galena de- Minneapolis, Minn. tained in both directions, night and day. December, 1916 THE ELECTRICAL EXPERIMENTER 587 LITES t 1TEN T S

Incandescent Lamp an ordinary buzzer is started vi- about at the upper surface of the Lion of the voice. This i, further brating in a pipe, Fig. 6. after the toy a piece of metal of any de- augmented by the use of a mega- (No. 1,194,643. Issued to Hans beyond the Kreusler, Hans Gerdien and Mar - column of air in the pipe is started sired form, as for instance, that phone chamber just cello von Pirani.) vibrating, it will take control of resembling a snake. mouthpiece. This patent relates to a special the buzzer and cause it to vibrate The permanent steel magnet con- construction of carbon or metal in unison with it. sists of a vertical post with a disk Tone Producing Means rigidly mounted on it which ro filament incandescent lamps and (1,199,534; issued to Melvin L. particularly to the use of a con- Battery Lamp tates within the top itself. When this is twisted by the thumb Sever) and George B. Sinclair.) centrated filament. The patentees (No. 1,200,366; issued to John F. post An electromagnetic scheme for claim that a carbon filament is su- Kerlin.) and finger the disk will cause it to perior to a metal filament in many rotate rapidly. The curved piece ways and that its temperature may of iron oscillates about the upped be run extremely high by virtue of surface of the top in grotesque the compact arrangement of the fashion. Several snakes may be filament spirals, etc.; and, more- agitated at the same time. The over, that the watt consumption of snake is best made up of convey the lamp is reduced. cross section and its form corn To further realize an improved posed of compound curves. the contains gas efficiency, lamp Theatrical Telephone Set (No. 1,197,543; issued to Charles P. Price.) Embraces a scheme for rigging producing various tones of any desired frequency. A rotor. or plurality of r3tors having projecting teeth is used and these are surrounded by tocthed stators having coils wound on them. The various alternating currents are passed thru a series of electromagnets which are polarized by This invention is one of the most battery current. Its magnetic field ingenious yet brought out. It in- first attracts, then repels, and thus volves the design of an extremely musical string. low -priced flashlight wherein the vibrates a battery bulb and socket, as well as Improved Coherer Scheme the switch are made up in the Radio ordinary dry cell container. (No. 1,201,034; issued to Edwin The reflector and socket elements R. Gill.) are molded in the pitch filler at The patentee of this invention the top of the cell. uses a considerable number of coup telephone transmitters and re- herers of the usual pattern, ar- Vacuum Tube Design ceivers to a small dummy figure ranged in a rotatable drum pro- such as used by a ventriloquist on (1,196,474; issued to Alexander the stage. The operator speaks to McLean Nicolson.) the dummy and his words are car- which is considerably above atmos- An ingenious vacuum tube de- ried by the microphone circuit is. pheric pressure, allowing the car- vice of the Audion type, which is the dummy's head down to as bon filament to be worked at high assistant below the stage. The as- current density. Mercury vapor is sistant can then (apparently) cause desirable for these lamps and is speak by intc carried in a small cup as indi- the dummy to talking cated. The gas filling may include the microphone in front of him some the speech being reproduced by the nitrogen or argon. loud speaking telephone receive - Strong glass bulbs are specified, dummy. also a wire mesh glass, as a pro- in the breast of the tection against bursting of the Cobererr chamber due to the high gas pres- Wireless Telephone Transmitter sure. (No. 1,200,210; issued to Frederick ]foyer Millener.) Electrical Sound Producer provided with an internal passa ?e- A multiple wireless microphone MI (No. 1,197,910; issued to Edward way, as shown. Hence the device unit comprising a plurality of mi- vided with switching attachments. E. Clernen .) may be placed in a vessel contain- First the coherer is connected to A novel scheme uti izing an elec- ing water or other liquid, and a aerial and ground and after it is trical device for vibrating a column stream of water may be caused to imprest with an etheric wave cur- flow thru as well as around the rent, it is the recipient of an in- bulb. The tubes contains the usual ductive discharge current from the filament, grid and wing. battery and inductance coil shown. The leads to the various electrodes are brought out by having Electromagnetic Bell wires fused into the glass; the op- (No. 1,199,699; issued to George posite end lead to the filament Henderson.) passes thru a glass tube. An improvement in a waterproof single stroke electric bell. Magnetic Top The lead wires are past thru a (No. 1,198,578; issued to George IT downwardly deposed conduit, as Reimer.) shown and the reciprocating parts, This invention relates to toys of including a striker, are accurately

crophones connected with the pri- maries of small telephone transformers and a suitable battery, as shown. The secondaries of these trans- of air in a horn or organ pipe, etc. formers are connected on parallel A column of air may be vibrated by and a compound effect produced bz a buzzer, Fig. 6, or by utilizing an the voice actuating all the micro- electro- magnet in front of a reed, phones simultaneously. This effect Fig. 5, the pulsatory character of is carried electrically thru the whose magnetic pull is occasioned condensers to the tadiophone cis - by the reaction of the vibrating cuit which is to be controlled. column of air on the microphone. Heavy currents can thus be modu- M; e.g., when the circuit is closed lated by the ordinary voice. thru the electro- magnet, the By designing the microphone reed is plucked, which reacts on chambers, as well as the tubular the microphone (M) and thus channels between them and the causes repeated plucks by the in- mouthpiece very exactly, it is pos- herent electrical control of the cir- sible to secure, in an as yet nat cuit brought into play until the he kind in which a magnet is very well understood manner, designed with an overhanging skirt column of air in the horn or pipe mounted for moving or agitating acoustic resonance and amplifies- on the head of the striker, so that is in full vibration. no water can possibly enter the ar- It is not commonly known that if COPIES OF THE ABOVE PATENTS SUPPLIED AT lOc. EACH mature chamber or that of the coil. 588 THE ELECTRICAL EXPERIMENTER December, 1916 PHONEY PATENT OFFIZZ Monthly Prize of $3.00 for the Best One Submitted No. N. w. s. O. S. A. FRANK FURTER OF HOTDOG, DEL. P. M. STAIRMOTOR Patent Amputated

To Whome It Quite Concerns: of energy must be doubled. This gives (10) Supply pipe through which the air is Be it knowed to All Ye and others, that, the overwhelming, titanic total of 34,816,800 fed to the turbine. (11) Outlet for air I, A. Frank Furter of the City of Hotdog, horse power gone to waste each day. In which may be used over and over again. in the County of Canine, in the State of one year this wasted energy amounts to It should be understood that all the bel- DELirium have succeeded successfully and the stupendous figure of 12,708,132,000 lows have check valves in order that the with complete success of inventing devis- Horse Power I!! air in pipe 10 remains under constant pres- ing and improving and otherwise creating This is far more power than is required sure at all times. a new means of making use of a tremen- to run all the electric lights, trains, f ac- Other technical refinements apparent to dous latent energy, which has gone to tories, power plants, vacuum cleaners, door any engineer need not be shown here, as waste since the days of Noah. bells and pocket flashlights of the entire they are obvious for the continuous opera- Now that it has been. calculated by our world and this energy hitherto gone to tion of the device. scientists that all coal will give out on our waste has been harnessed by me, now and What I claim is: planet in less than 100 years, it is of the forever after. (1 °) A stairmotor, making stair walk- tallest as well as highest importance that As all great inventions, the Stairmotor ing easy, on account of the pneumatic tread. a new supply of energy must be found to as my own revolutionizing discovery is (2 °) A stairmotor working equally well provide humanity with heat, light and termed, is so simple that it will make great on hot air as well as cold air merchants. power. inventors turn a vivid Paris green with (3 °) A stair motor, which by compres- Ever since the earliest dawn of humanity envy. sing the available air supply of the earth, man has walked up and down (and fallen The accompanying Patent Drawing re- keeps it from becoming hard of old age. down) stairs. Every time a man walks veals the invention better than words could In Halfwittedness whereof, I have here- up (or down) a stairway, say 50 feet high, do. For those Boneheads, however, who upon exprest and supprest my glorious this man-with an average weight of 150 are devoid of understanding, the follow- nom -de- plume, this 11th morn at 7 A.M. lbs.-expends a useful energy value of ing short description will be of use. in the afternoon while the telescope regis-

.ASy/.ra5i:64.i._... 4 %

The Efficiency Engineer of To -day Is Truly a Wonderful Being. Here We Have an Electro-Pneumatic Contraption by which the Energy Wasted in Ascending and Descending Stairways May Be Applied to a Series of Bellows which Pump Air Into a Hot -Air Motor; This in Turn Drives an Electric Dynamo Charging a Storage Battery. Why Pay $3.4982434 per Month for Electric Lights?

7,500 foot lbs. Exprest in Horse Powers (1st) Air turbine driven by comprest tered 65% Fahrenhide in the shades of this comes to .2275 Horse Power for one air which is produced by stepping on Hades, taken on the 99th Degree latitude man scaling the stairway. Just think of the steps. (2) Dynamo propelled by the by 78%% lassitude west of Green which. this colossal waste. Now careful statistics turbine which in turn charges the storage show that on this globe at least 978 mil- batteries thus collecting all energy. (3) A. FRANK FURTER, lion people walk up a flight of stairs of Switchboard. (4) Storage Batteries which By His Attorney, an average height of 32/ feet each and collect the "juice." (5) Tungsten lamps John Golubski, every day (Sundays and Holidays includ- of tetrahedral design. (6) Lower side Chicago, Ill. ed). This gives a grand total of 17,408,400 board of stairway. (7) Hinged stair-steps. Witnesses: Horse Power a day. But as the 978 mil- (8) Bellows which charge the turbine. (9) Mack Arony. lion people must walk down again also Spring to bring steps back to original posi- Phil Harmonic. during some time of the day, the amount tion after it has been comprest by Man. Pete Roleum. December, 1916 THE ELECTRICAL EXPERIMENTER 589

41412 tarQUESTION Box

This department is for the sole benefit of all electrical experimenters. Questions will be answered here for the benefit of all, but only matter of sufficient interest will be published. Rules under which questions will be answered: 1. Only three questions can be submitted to be answered. 2. Only one side of sheet to be written on; matter must be typewritten or else written in ink, no penciled matter considered. 3. Sketches, diagrams, etc., must be on separate sheets. Questions addressed to this department cannot be answered by mail free of charge. 4. If a quick answer is desired by mail, a nominal charge of 25 cents is made for each question. If the questions entail considerable research work or intricate calculations a special rate will be charged. Correspondents will be informed as to the fee before such questions are answered.

HIGH FREQUENCY noies is to change the present position of spark from one of your fixtures is that ALTERNATORS. your transmitting apparatus, and see that one of the transmitting terminals is (666.) A. Baldock of Middlechurch, the connecting terminals of the various grounded thus causing this effect. We Manitoba, Canada, wishes to know: parts of the transmitter shall be so set that would also advise you to reverse the aerial Q. 1. Would it be feasible to,use several they are at right angles to the telephone and ground terminals of the oscillatory line, thus reducing the induction between circuit. You should have no trouble then oAltt 0.4/12 o A/t..r the two conductors. We would advise you in eliminating the spark appearing in your r 6eor also to connect one of the nearest tele- fixture. Too small a ground wire has been hwe( known to cause this trouble. sen co // Q. 3. What is the approximate distance the stationary electrodes should be set away TO OUR FRIENDS. from the rotating contacts of a rotary gap &coi/ Do you realize that not one day with a / K.W. transformer, having a sec - passes when we do not receive from ondary voltage of 13,200. 150 to 250 or more letters addrest to A. 3. The sparking distance between the the "Question Box"f If we were to rotating member and that of the station- 0 666 AC publish all the questions and their an- ary should be about W. However, this swers we would require a monthly is only a guess as the factor of the dis- Connection of Three "Gear Type" High Frequency depends Alternators In Series with Battery Excited Fields. magazine five or six times the size tance between the two electrodes of The Electrical Experimenter with entirely upon the resonance condition of high frequency generators, as described on no other matter but questions and an- the oscillatory circuit consisting of capacity page 415 of the October, 1916, issue for gen- swers! Of late the influx of letters and inductance. Therefore, the condenser erating power for other purposes than test- a has become so heavy that several of capacity is a prime factor determining the to sparking distance. Transformer having ing crystals? M our associates have been forced A. 1. Several high frequency alternating discontinue important editorial work, voltage you mention is right. It is advis- generators may be used in series; the elec- in order to answer the mail. This we able, however, that you should use a hot tro- motive force of the total generating unit are certain you do not wish. You do wire ammeter in series with ground cir- can be increased so that it will be possible not want your magazine to lower its cuit and experiment a while with the dis- to use it in radio transmission work. How- present high standard. You want the tance between the electrodes until maxi- ever, the efficiency lost in operating such best, the very best, and you know we mum reading of the ammeter is obtained. machines in series or even in parallel is so never have failed you yet. AUDION great and the energy developed when such Moreover the multitude of letters DETAILS OF CIRCUIT. wholly unnecessary. Most of the (667-A.) Kalman Bernstein of Brook - an arrangement is completed is so small, are know. it would not be practical for serious questions we are asked every day yn, N.Y., wishes to that Q. 1. Could you give me a few sugges- work. Furthermore it is necessary to syn- have been answered before in the Question Box. Therefore ere you ions for the improvement of the Higgs chronize each individual machine in the in in the generated sit down to write to us, look over Audion circuit arrangements published complete unit order that 1916, issue? E.M.F. and current shall be sinusoidal. your back numbers and nine times the Junes Q. 2. What is the voltage and amperage out of ten you will find the answer. of each machine? IWe strive hard to publish only ,---/400 /0rns4/r/re A. 2. The current generated by such a such matter as has not appeared be- / -/500 -N turns s6on-el machine would be in the neighborhood of fore in our columns, and for that les Ls about .1 of an ampere, and the voltage may 7eason only a small fraction of que- be as high as two to three volts, so it is ries of those received by us are ac- quite obvious that a large number of them a tually published. will be required in order to use the current = Kindly note, therefore, that in the generated by the complete arrangement for future we cannot, in ycur own in- Ls radio telephony. As the amount of current o---M terest, answer questions by mail, free necessary for satisfactory transmission of charge. Ls work is in the neighborhood of 50 watts, For questions requiring immedi- this means that about 50 or 100 volts are re- ate answer our fee is 25c. for the iootums fis,r/ie 800 #14 quired with a current of / to 1 ampere. first ordinary question and 25c. for Q. 3. Give a diagram of connections for each additional question. We will using several machines. gladly advise fee for special ques- A. 3. The diagram herewith gives the tions entailing considerable calcu- connections for three units ; however, more ffl lotions or research. Stamped and can be connected as desired. addrest envelope should be enclosed with the queries and, more - NOISES IN THE HOUSE s over, any sketches accompanying TELEPHONE. them should be made on separate (667.) Rudolph Wenski of Cleveland, sheets. And please be brief. Ohio, inquires: THE EDITORS. Q. 1. When I use my transmitting apparatus it makes such a noise in our house ; telephone that it cannot be used. What can be done to remedy it? phone conductors in series with a condens- A. 1. The only reason we can see for the er to the ground and in this way carry noises in your telephone is that one of the away the induced electrical disturbance. 2. one fixtures can transmitting wires are either parallel to the Q. In of our a spark Details of Composite Audion Receiving Circuit telephone line or else they are touching it. be heard whenever I send. I have a kick- Adapted to Long and Short Waves. It may also be due to induced currents back preventer connected across the line, from the oscillatory circuit of the trans- consisting of 2 one -M.F. condensers and A. 1. We cannot give you additional im- mitter produced in the neighboring tele- the center connection grounded, but this provement over the circuit which has al- phone line. The only means which you can does not help in overcoming the trouble. ready_ been published. employ for eliminating these unnecessary A. 2. The reason you are obtaining a {Continued on page 594) 590 THE ELECTRICAL EXPERIMENTER December, 1916

A GIANT ELECTRIC TORPEDO the telegraph, the dispatcher writes down inous in the dark, contains a base of zinc THAT EATS THRU THE EARTH. the order only when it is repeated by the sulfid, together with a small quantity of operator and may not catch the errors in radium bromid, the (Continued from page 551) alpha -particles of the repeat due to _ the natural impulse to which, continuously bombarding the crys- When it is planned to fire a subterrane write down the message as originally sent tals of the sulfid, render it luminous in the torpedo at a fortress, or a citadel, the ma- out by him. Photos courtesy Western dark with a pale greenish glow of about chine is lowered into a trench at the de- Electric Co. the intensity. of a rubbed phosphorous sired depth and carefully aimed towards match. By increasing the quantity of rad- the doomed place. It is then started on its WHY A MERE SPECK OF RADIUM ium compound included in the paint the way. Several days will elapse before it COSTS $5,000. more brilliant can this phosphorescent glow reaches its goal, maybe several weeks. All (Continued from page 555) be made. On aeroplane compasses used by the time, however, the engineers are listen- crystallization. Then the radium chlorid the European armies, the luminous corn - ing at the telephones that communicate and barium chlorid are treated with am- pound employed is of such intrinsic bril- over the cable with the microphones in its monium carbonate and the carbonates se- liancy that its glow can be seen even in machinery and when at last they know it is cured are dissolved in hydrobromic acid contrast with twilight. Such a high mix- below the fort they have only to touch the and are evaporated, giving bromid crys- ture of radium compound, however, rap- button that closes the electric circuit and tals. These crystals are then sealed up in idly disintegrates the zinc sulfid so that the makes a spark in the explosion chamber, glass tubes, and finally by what is termed life of the paint when may be barely twelve 400 cubic feet of dynamite or lyd- "higher fractionation" the radium is separ- months. In the intensity to be used on the dite will hurl the enemy s fortifications ated in the form of radium bromid. new switches, into which has been found most the air. This is the present final state. Science practical for average use on watch dials, up to now has not succeeded in producing etc., the figures are readily visible in a pure radium metal. darkened room, and such paints have an GUIDING TRAINS BY TELEPHONE. It has been calculated that the radium assured luminous life of ten to fifteen in the ore is exactly or nearly 1- 200,000,- (Continued from page 556) years, if not longer. This latest product 000 of the bulk, so it is easy to see that does not secure an additional require to be placed in the light in circuit by means of having to pass tons of material thru so order to make it glow. The action is con- the phantom. many delicate processes, in order to secure tinuous, being due In October, 1907, to radium. the first successful in- what anyone would call a speck of dust, In order that ordinary flush switches al- stallation of telephone and selector equip- is a fair reason for the great cost of the ment ready installed may be made luminous, the for train dispatching was completed radium when secured. electrical manufacturer on the lines of the New York Central. This referred to has de- It is now claimed, tho it has not been vised the ingenious expedient of luminous - was closely followed by a number of in- proved to the satisfatcion of some critics, head stallations on the Chicago, Burlington screws which can be used to replace and that radium can be produced in the United the present screws, giving visible points of Quincy, where it was proven, to the satis- States for something less than $37,000 per faction of officials of roads luminosity by which the switch can be lo- other watching gram, which is less than half of what it cated in a these first service tests, that the telephone darkened room. cost in the open market two years ago. Possibly the most widely useful applica- and selector combination could be used It should not be forgotten in trying to equally well for single track as for double tion of the genuine luminous radium paint explain the cost of radium that it costs is on watch dials. One of the largest and multi -track operation. labor to get out the ore, and that it is now These pioneers in telephone dispatching manufacturers of watches in America has valued at about $120 per ton. made preparations to bring out on the mar- blazed the trail for the network of rail- There is another reason, aside from that roads traversing the United States and Can- ket even very cheap watches with rad- of production, which will go far toward iumized dial figures and also the hands of ada. Out of a total of 285,000 miles of rail- explaining the value of radium. Just be- road in the two countries over 95,000 are these watches will glow on the darkest now equipt for cause there is so great a demand for it night. this method of handling, all the world over the market value is train movements. Not only is the tele- It is reported that this particular watch phone and great, as is the case with any commodity manufacturer has spent $10,000 for the in- selector equipment used on the of which the supply is very limited and train wires, but similar apparatus is used itial outlay in purchasing the necessary on message wires for which the need is great. radium. The radium is mixed with a for the transmission of Radium is being messages other than those relating to train used for treating many rather large quantity of zinc sulfid and orders. diseases, from cancer all down the line to when ready for application on the watches, With the telephone, minor skin affections and inoperable dis- as already outlined, the manufacturers' cost the dispatcher issues eases. Study of radium orders verbally, using the same terms and itself has shown amounts to about $1.00 per square inch of forms as he would with the telegraph, his that there are three main streams of rays the treated area, it is said. speed being limited only by the rate at emanating from a bit of radium. They One of the large electrical concerns is which the operator can copy the messages. have been called the Alpha, Beta and Gam- said to have successfully experimented with The average railroad telegraph operator ma rays. radium in a storage battery. A mere speck sends at the rate of 25 words a minute, If a magnet be held near a bit of radium of the precious substance, properly placed while a speed of 100 words or more is pos- it will attract the Beta rays most strong- in the electrolyte of the cell is stated to sible with the telephone. It is only natural, ly, the Alpha rays next, but the Gamma have produced wonderful results as re- rays not at all. It is of im- therefore, that more business can be the utmost gards output in ampere-hours ; even to the* handled by the operators with less physical portance to control these various rays, for point of boosting the output 25 to 30 per effort. Complete reports of the passing, while one kind are adapted to one affection cent above the normal rating. arrival or departure of trains can be given another may be required for a second, [Those interested in radium will find a in the fractional part of a minute and in- while the first should be shut off. It has valuable discussion on its properties and formation regarding accidents and other been found by experiment that a thin sheet energy components in the September, 1915, occurrences outside of the daily routine sent of metal, or even a sheet of paper, will issue of this journal procurable at 15 cts. to headquarters verbally in such complete shut off the Alpha rays; a much thicker prepaid from the publishers. -Ed.] form that the chances of misunderstanding piece of metal is needed to shut off the and the necessity for additional messages Beta rays, and the Gamma rays will pass RADIO DRAFTSMAN WANTED. are eliminated. thru anything but lead, and that must be of Those who are well- versed in the radio When the dispatcher wishes to call, he considerable thickness to shut them off. art and are experienced in general electri- turns a key corresponding to the station A safe for holding radium has therefore cal drafting, have an opportunity now to with which he wishes to communicate. The been constructed of very heavy walls of obtain a radio draftsman's position, which loud ringing bell at the station called in- lead inside the steel chamber, so that the is being offered by the U.S. Government. sures an immediate response, whereas the radium does not escape, or, rather, make Examinations for this position will be comparatively feeble click of the telegraph itself felt in the room outside the safe. held in all the principal cities where Civil relay or sounder frequently causes a delay There is no thought of stopping the emana- Service examinations are given, on No- in answering. Furthermore, other stations tions, for that has heretofore proved im- vember twenty -first. may be cálled in on the line while a mes- possible, and besides, a grain of radium Those who desire to qualify for this po- sage is being transmitted. This is a fea- will outlast many generations; so why sition are advised to communicate with the ture used continually on heavy traffic divi- economize in a practically inexhaustible Civil Service Board at Washington, D.C. sions where there is a high rate of calling. source of energy? This is the first opportunity offered in Accuracy in transmitting orders is as- The extraction of radium, properly con- many years to those who desire to enter sured by the practise of having the dis- sidered, is therefore only one of the con- the radio field. patcher write down the words as they are centration of all of the stored up energy Information as regards salary, qualifi- spoken and checking this record. word for in the ore into the smallest possible bit, cations, application blanks, etc., can be ob- word, as the order is repeated back by the and this may explain why it is so costly. tained by writing to the Chairman of the operator who has previously written it down One of the latest preparations for this Board of Civil Service Examinations, simultaneously with the dispatcher. With purpose of rendering certain articles lum- Washington, D.C. December, 1916 THE ELECTRICAL EXPERIMENTER 591 too n NOTE THAT PEAK 73

THE peak is what you get on a RA-6 regenerative receiving set-100 times amplification. The lower curve is the response you get on an ordinary set. Just imagine the amplification -100 times-and the selectivity is just as great as the amplification. No damping in that peak signal, no interference even if that other station is on the same wave. When you get that peak, you are getting all there is to get out of any incoming signal. everything under the sun to hold How many times have you had a signal fade out, and tried gs it just a second or two longer ? Then study that peak. Note the difference -see all the strength of signal you have to spare over the strength of signals over an ordinary set. How about the stations you have never heard? Stop worrying because the fellow-with-the big aerial hears them and you don't. That peak will bring them in. 1 he RA -6 will give you that peak. This instrument is super-efficient, super- selective and supersensitive. It was o designed especially and solely for reception of AMATEUR-WAVE LENGTHS and its development has been carried on over a period of two years. It was the FIRST and is the ONLY worthy adaptation of the Regenerative circuits to short-wave reception. The antenna inductance is arranged in steps. ASIDE FROM THIS THERE ARE NO SWITCHES. Continuously variable inductances-carefully designed variometers are used in the closed circuits. HIGH RESISTANCE CONTACTS, the capacity of switch points and leads, end - turn losses and the necessity for a variable tuning capacity are thus EN- TIRELY DONE AWAY WITH. The antenna and closed circuits are INDUCTIVELY COUPLED and the COUPLING IS VARIABLE. The component parts of the instrument are not crowded into a small cabinet. The fact that ALL of these things are of extreme importance has been proven by the here- to-fore unheard -of SELECTIVITY and AMPLIFICATION obtained by owners of this instrument. Signals may be read from stations at extreme distances or through heavy static and interference with this instrument long after other receivers have failed, and WEAK SIGNALS MAY BE AMPLIFIED UP TO ONE HUNDRED TIMES USING ONE AUDION ONLY. The RA-6, price 335, is as perfect mechanically as it is electrically. It is made right. Everything used in it is the result of long trial and experiment, to make a short-wave set that would give the greatest possible response to any incoming signal, on 180 to 580 meters. R.A. -6- PARAGON AMPLIFYINC. SHORT -WAVE RECEIVER, $35.00 Make that peak work for you now. Write us now. Range 180 t 580 Metes PARAGON WIDE RANGE RECEIVING TRANSFORMERS The methods employed in winding the coils eliminate leakage due to coloring matter in the insulation, put an end to the press ence of moisture in the varnish, insulation and tube. The coils of the Paragon "No- End -Loss" transformers are divided into sections and fitted with self -cleaning, positive- action end-turn switches which connect and disconnect the winding as .required, entirely cutting off from the circuit unused portions of the inductance and completely eliminating end -turn effects on all wave lengths. These switches are enclosed and are automatically controlled by the primary and secondary inductance switches respectively. Panels, housings, switch heads, etc., are of polished black FOR- MICA, which is superior in every way to hard rubber and costs more. All metal parts are of gold lacquered brass. These instruments are adapted to extremely close tuning and due to the absence of end -losses are particularly recommended as the only receiving of wave- RECEIVING TRANSFORMER transformers on the market suited ro the reception amateur PARAGON or forusein conjunction with the AUDION-DETECTOR. TYPE "L" $22.50 TYPE "S" $30.00 TYPE "X" 335.00 lengths Paragon Instruments Have Set New Standards They are in a distinct class by themselves. There are no other instruments which can EQUAL CAN PROVE THIS ERTION TO THE SATISFACTIONdOF ANYONE WE SEND STAMP TODAY FOR BULLETIN "O" WHICH DES- CRIBES A VARIETY OF (ENTIRELY NEW TRANSMITTING AND RECEIVING SPECIALTIES OF PARTICULAR INTEREST TO THOSE WHO DESIRE THE BEST. Send 6c. for our 232 pp. Catalog

Our No. 7 Catalog shows several hundred different Contains complete des- parts and also sets of materials for building your cription and prices of own apparatus. We do the latest Wireless all the difficult work in our all factory and give you the and Electrical Goods. benefit of machinery and VARIOMETER equipment. Wound for any range. A neces- LOADING COIL sity for the proper tuning of the Audion circuits on ea.00 For long e OUR PRICES WILL SAVE YOU MONEY AND OUR PROMPT DELIVERIES wave lengths. wave work 8.00 WILL SAVE YOU TIME short THE BEST CATALOG OF ITS KIND IN AMERICA Adams -Morgan Co., Alvin Place Upper Montclair, N. J.

You benefit by mentioning "The Electrical Experimenter" when writing to adve) isers. THE ELECTRICAL EXPERIMENTER December, 1916 * * * * * * * * * * ** * * * * * * * * * * * * * * * * * ** "' * * * * R a C i * "USE RADIOCITE IN YOUR DETECTOR AND FORGET IT" * iss the most wonderful of all One of the important features of RADIOCITE * * radi crystals. It is more sens tive than is that it does not jar out easily. Each crystal * Galena and far more sensitive than ANY is tested for sensitivity and guaranteed. RADIO - other crystal or mineral. RADIOCITE is a CITE comes packed separately in a box, wrap- specially selected grade of a rare crystal chemi- ped in tin -foil. Full directions accompany it. / tally treated by RADIOCITE can . - * our own secret pro- I be mounted like cess. HAT T S an other crystal; * The mineral that it may be clamped looks like liquid gold. It has a highly and between springs, but it is best to set it in Hugo - * wonderfully polished surface giving it a bur- nium soft metal. Money refunded if our claims nished appearance. This crystal is now in use are not substantiated. by several governments, and is conceded to be No. 3939. Generous piece of tested RADIO- the most satisfactory of all. It is used with a CITE. Prepaid, $0.50. medium stiff phosphor bronze spring, or with a THE ONE UP =TO =DATE MINERAL stiff silver wire, about No. 30 B. & S. Gauge. WHICH EVERY AMATEUR MUST HAVE

Electro Importing Co., Fulton Cleveland, 236 St., Sept. Ohlo h, 1916. New York Gentlemen;-

Your piece lent condition of radiocite and received in inform excel- that It he best mineral it Is has any ever icon pute or on the and back galena beat market. again. have forty differentere consistingand b I tried waysw of it out a piece on an indoor r a gas pipe bare copper a et ground wire , forty 20 Brandes a cent detector long, phones.s. feet This r and a of set was pair of testingtes use d Radiocite merely for and the off my the result purpose feet ", have s if I not yet Obtained it works trie g ed'me it big set I'll have tas did but "soas on the small me" set.ee mset - why,

Yours truly t.III taWMNM,* .3i6í it2=`

One of the hundreds of unsolicited testimonials received by us. Electro Importing Co., 5 236 Fulton Street, New York City. IMMEDIATE SHIPMENTS. On your absolute guarantee that NO DELAY ßsnrocrri is exactly as described by S you, I enclose herewith 50 cents in for which you are to send nu. , prepaid one box containing a generous Importing Co., piece of tested Radiocite. You accept my, Electro money with the understanding that you will , refund it to me at once, should I find the ItsniocITE unsatisfactory. Youguarantee to chip 236 Fulton St ,N.Y. within twenty-Jour hours or return my remittance. , Name State %t******************** You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER :93 ********************************************** pe announcement MEDICAL COILS * IT'S LIKE this. AND THE authorities. s * s s s s OVER TWO ears ago. TIRED MAYBE. ' s s s s WHEN EVERYTHING was peaceful. FROM OUR yelling. * s s s s WE ORDERED from Germany. GAVE IN. * s s s s CASES OF ElectricalGoods. AND THE goodsare here. * s s s * s These colla, which come into use more and more AND OTHER Things. AND YOU can buy them. every day, are adapted for the treatment of rheu- * s * * * matiem, neuralgia, nervous complaints. etc. Per- THEY REACHED Holland safely. CHEAPER THAN ever. sons who suffer from rheumatism in any particular s s s * s s part of the body sometimes find much relief from ON THEIR jo urney to New York. FOR FURTHER information. the use of electricity in this form. An ordinary s s s s s dry cell not furnishedby us will operate this coll. s This coil is really anexcellent artlele.Theetrength AND WAR broke out. READ THE ads. of current is regulated by the regulator at the right s * s * * s side of coil. Pulling the graduated tube out in- AND PUT a stoptto their journey. ON THIS page. creases the strength. pushing It ,n decreases lt. s s * Two kinds of currents can be taken off by means of the three bindin poets. The identification AND ALL the time. platee of the posts are imitation ivory. A switch s * s to turn the current off or on is provided. Base WE HAVE k *pt o*n writing. is of solid walnut. Handles highly nickeled and polished. TO THE authorities higher up. Large size Medical Colt primary and secondary connec- s s s tions, 3% x 4M, inches. with battery switch. AND WANTED to know. Shipping weight, 1 lb. - - - - Off s * * Only 480 on hand. If sold, money back. 9JC WHY THIS hold -up. * * s AND RESPECTFULLY requested. s * s TO LET peacefulFpeople. GEISSLER TUBES ENJOY THINGS. s * s PAID WITH good. WE THANK you. 1JLh:ilbi.+IJIJ11 * s s AMERICAN DOLLARS. With apologies to K.C.D. Here is offered what is to our knowledge the only supply of real imported Geissler tubes in the country. To say this is an unusual offering is putting it mildly. These tubes are of the fluorescent liquid type only and the IMPORTED SELENIUM CELLS colors they show and the effect they produce Everybody has read about the experiments of Tele- when run on even a half -inch spark coil or ,a photography (sending photographs over a wire hundreds of static machine is certainly beyond words to miles> made by Professor Korn and others. It is also known express. Remember this is the only that if the problem of tele -vision is ever solved. the selenium - can cell will play an important role. Our Selenium Cell Is the stock in the country and no more one used by all prominent experimenters. This cell has come in until the war is over. The colors been imported by us for years, previously to the war. We and shape vary in each tube, no that hardly have only a limited quantity on hand now and will not be two are alike. able to get any, until the end of the war. No. 1128A, Fluorescent @Liquid Geissler We guarantee every cell. Aube, Length 1114 inches, Imported Stlenlum Cell, each, shipping weight, 4 oz. $10.00 eh. wt. 2 lbs. - - PAPI 25 each Only 48 on hand. If sold, money back. Only 362 on hand. If sold, money back. "The Livest Catalog in America" SENT FREIE TO YOU 1/2 inch THICK == WEIGHT 1 2 lb. == 658 ILLUST.

What Catalog No.16 Contains and Shore Wireless Stations, besides a great many useful tables and formulas. It contains the largest assortment of This valuable book is 7x 5% inches in Wireless and electrical experimental size and 32 inch thick, and well bound. apparatus shown in any catalog published. In addition are shown Com- IT IS SENT FREE mercial Wireless Sending and Receiving Some of the questions answered Outfits, Electric Motors, Dynamos, in Cyclopedia Catalog No. 16: Flashlights, Medical BatteriesBatteries, High Thr2 WireidSo Law of August 13, 1913. How to Receive Wireless Messages. Frequency Apparatus, Plating How Far You Cin Telephone by Wireless. Toys, Printing Presses, Tools, Sporting Wave Lengths oIt Principal Radio Stations. Goods and the LARGEST Scientific How to Erect sWireless Aerial. Book section published. This book will How to Receive Time by Wireless. 1111 MM - - give information as many How to Photograph Electri al , you as much Discharges. books that cost you $1.00 or more. It How to Experiment with Spark contains 658 illustrations, 2,000 articles, Coils. How to Test Storage Bat- complete Code Chart of Morse, Conti- teries. nental and Navy Codes, sixteen -page How to Make Tesla , "TREATISE ON WIRELESS TEL- Experiments. Call Letters of all Corn- EGRAPHY," list of Call Letters of U. mercial and Gev- Electro Importing Co., S. Government and Commercial Ship Size 7x5V1"= -2000 Articles ernment Wirele,s 236 Fulton Street, New York City Stations. Please send me FREE your latest Cyclopedia Catalog No. 16 con- ,taming 275 pages, 658 illustrations and Electro Importing Co., diagrams, including Treatise on Wireless Telegraphy, complete list of all U. S. Wire- '. loss Call Letters, and 20 coupons for your Or 160 page Free Wireless Course rn 20 lessons. Fulton St ,N.Y. E.E. 12 236 Name ddress ********************' State You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. THE ELECTRICAL EXPERIMENTER December, 1c9í6

QUESTION BOX. (Continued from page 589) Make It a Real Q. 2. What capacity are each of the three variable condensers shown on the right hand side of the diagram? Begin with the upper one. "Wireless Xmas" A. 2. We again publish complete circuit in which we give full details as to the size of the condensers used and data on the in- NO better Christmas gift for anyone interested in wire- ductances. Q. 3. What sort less could be imagined than the " Best 1 KW. of coils are L8 and L9? Transformer Are they a loose coupler with a secondary Ever Designed," the new and a primary, or do they remain stationary at a certain distance apart? A. 3. The inductances L8 and L9 are inductively coupled and both coils are connected in series as in the diagram. The complete inductive coupler can be obtained THORDARSON by employing the secondary and primary of a loose coupler. However, it is advis- WIRELESS TRANSFORMER able that you should use two coils wound with the same wire. A new perfected type, with even CURRENT CONSUMPTION. (668.) James Green, Jr., S.C., asks as greater range, power and flexibility follows: than our former model. Exclusive Q. 1. Is there any formula by which cne can figure the current in volts and amperes Variable Shunt and Ampere Scale that a 1" spark coil or a % K.W. transformer draws? give wonderful accuracy. Comes A. 1. The simplest rule which you can completely assembled use for determining the amount of current -no chance and voltage that a 1" coil consumes is that for mistakes or burn -outs. Five which depends entirely upon the construction of the transformer, that is to say, some sizes, from % to 2% kw., 10,000- coils have a larger number of turns than 20,000 others, consequently consume less current volts, any cycle desired. than the others, but at the same time producing the same effect due to the fact that Write the total magnetic flux generated by an for Special Bulletin and Prices electric magnet depends upon the number of turns and the current squared. Con- Thordarson 506 SO. JEFFERSON STREET sequently either factor can be varied to Electric Mfg.g Co., CHICAGO, ILL. give the result desired; thus by increasing the number of turns the current is decreased and vice versa. Q. 2. When a transformer is rated at 110 volts and 5 amperes, does it mean that the transformer can run on this current, or that it draws that much with key de- LENZITE WIRELESS DETECTOR pressed? Patented May 2nd, 1916 A. 2. Whenever a transformer is rated K.W. it means that it will consume 110 volts and 5 amperes. The additional 50 Recognized by leading watts which it takes represent the losses inherent in the transformer which is ac- authorities as the most sen- counted for eddy currents and hystereses. sitive and most effective De- ELECTROLYTIC RECTIFIER. (669.) J. G. Chaffee, Conn., inquires as tector existing. If not satis- follows: fied, return same Q. 1. Can an A. C. arc be used in wire- and money less telephony? If not, why not? will be refunded. A. 1. An alternating current arc can successfully be used for radio telephony providing that the voltage across the arc is high enough to keep it burning constantly. A very good method which has recently been employed by several prominent en- Dealers wanted in gineers about the country is that involving a high tension transformer giving say unoccupied territory about 14,000 volts as secondary potential and connecting it across an ordinary carbon arc shunted with a regular oscillatory circuit comprising a variable capacity and fixed inductance. It is then possible Write for booklet to use the alternating current arc as a generator for high frequency current as and further infor- Price used in radio telephony. The modulation of the oscillatory current is controlled in mation to complete $ 5.00 the ground circuit. It is impossible, however, to use an alternating current arc which is connected directly to 110 to 220 LENZITE CRYSTAL volts alternating current mains, as the volt- CORPORATION age of an alternating current at such low 537 Chamber of Commerce Building Pasadena, California potential is unsteady, thus causing the arc to flicker, consequently not permitting the oscillatory circuit to have a chance to build up the high frequency currents. You benefit by mentioning "The Electrical Experimenter" when w iting to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 595

Q. 2. What is the maximum output of a 4 jar electrolytic rectifier used on 110 cycle volt, sixty A.C.? Ï/%/G//%-`i, A. 2. The maximum output of a 4 jar electrolytic rectifier is about 40% of the Preparedness 11011111111 input. 1111111R Q. 3. Can the de Forest type T tubular Audion bulb be used te transmit a wireless In War or Peace telephone message? If possible please give hook -up. A. 3. The de Forest type T Audion bulb ` Use Bunnell Apparatus No. S833 Dandy Loose Coupler $6.00 can be used as a generator of high frequency current for radio telephony providing a proper connection is employed and Best and most durable. Our Cata- the diagram herewith gives one of the lat- log 36E est connection schemes for a radio tele- Up - to - date dealers phone employing a tubular Audion. illustrates have them in stock. and describes about ,VC. 300 articles of wireless No. 8654 Dandy 31 Plate Variable apparatus Condenser $3.75 as well as 112 other appliances. Send 2c. stamp for it, to J. H. Bunnell & Co.'s No. 8804 Jove Crystal Detector Holder Radio Dept. On Dark Porcelain Base . . . $1.25 New On Handsome Composition Base . . . 1.50 32 Park Place York Q 669

Hook -up for Using the "Audion" as a Radio- phone Generator and Transmitter. Nauen, Germany t0 LIGHTING QUERIES. (671.) Walter H. Lombard, Southbridge, Mass., wishes to know : Pittsburgh, Penn. Q. 1. Can a residence be lighted with 30 volt A.C. lamps for your residence by em- Undamped signals cuit, by putting in a transformer to reduce voltage to 30. volts? were recently received A. 1. You can satisfactorily operate 30 over this great distance volt A.C. lamps for your residence by employing a step -down transformer in the 110 by the DHE Station volt line circuit. We suggest, however, that at Pittsburgh, Penn. you should use directly the 110 volts as a certain amount of loss is encountered in the transformation between the 110 and 30 volts. RADIO Q. 2. Would lighting be as satisfactory if same candlepower bulbs were used as 110 volt service, and how would cost com- PHONES pare? were used. Nothing special; simply our Standard A. 2. Lighting would be satisfactory if you would use the bulbs having the same Set, no amplifying device in circuit. candlepower as that used on 110 volts. Send for Booklet 1687X Larger size conductors are necessary, how- SATISFACTION GUARANTEED OR YOUR MONEY BACK ever, to care for the increased current. THE HOLTZERCABOT ELECTRIC C° BOSTON.B O M A S S. STORAGE BATTERY. 6161.65 SO.STATE ST. 101 PARK AVENUE. 1104 URIC TRUST ÓIÄ0. (672.) Francis Ziesse, Bronx, N.Y.C., CH I C A O O NEW YORK BAL T IMOR B wishes to know the following: Q. 1. What size wire is used to wind a loose coupler with a diameter of 6 inches and 18 inches long. Also how many layers. A. 1. The primary should be wound with THE NEW TUBULAR MICA MONOTONE a single layer of No. 20 B. & S. copper CONDENSER IMPROVED QUENCHED GAP magnet wire and the secondary should be wound with No. 24. Q. 2. What causes a storage battery to lose its power at certain times and only able to regain it when shaken? A. 2. The only reason that we Composed of a special mica possessing infinitesimal can de- Are you a leader follower in adopting up- to-the- duct that would cause the inoperative ac- leakage. Its efficiency permits use across your tuners apparatus? with in place of massive load coils, to raise wave. Use in thenfamous MONOTONE ÌMPRpOVED QUENCH- tion of the storage battery when kept still place of your present fixed condenser and note quality ED GAPS, .which are a big improvement over the is that it may be due to the gas bubbles of tone and amplification. Made in two capacities, original MONOTONE GAP. Span that freak dis- one capacity for grid of audions and tubular detec- tance on powerful waves of RADIO ENERGY. Each formed on the positive plates of the stor- tors, and one for crystal detectors. Individua. capac- plate carefuly machined. Best mica. Adjustable. age batteries which causes a considerable ity marked on same, tested from standard furnished One unit of Uie new gap for spark coils up to3 ". One by Bureau of Standards. Specify purpose. A high ef- unit for every h K.W. plover of transformer. Spe- int,rease of resistance between the negative ficiency, cially recommended for powers below i<. K.W. Parts beautifully finished permanent condenser, nickled and polished. You will be pleased with this and positive plate. This would reduce the guaranteed. Postpaid $2.50 Each. new gap. Guaranteed. Postpaid $2.50 Each. current considerably, in fact, to nil, and by THE RICHARDSON CO., Manufacturers of Radio Apparatus shaking it up, the gas bubbles are broken ERIE, PA. (Continued on tage 597) You benefit by mentioning "The Electrical Experimenter" when writing to adverti: ers. THE ELECTRICAL EXPERIMENTER December, 1916 TURNEY'S PAGE By glancing at this cut yo can almost feel the real comfort this L . set affords LOOK IT OVER THE NEW TURNEY HEAD SET With Adjustable Pressure Head Band The peer of them all German silver head band Four new features Bakelite ear-caps Three thousand ohms Consequent pole pieces Flexible back support Soft, clear tone Positive friction adjustment Weight nine ounces No screws to catch the hair Can you beat it?

Patent Applied For ULTRA SENSITIVE CRYSTALOI DETECTOR PRICE $7.50 Mailing Weight One Pound Over 10,000 Sold Never in the history of wireless has any single wireless instrument made such a phenomenal record as the Crystaloi. It is sensitive, permanent and handsome. Adjustment is made by turning the wheel. Every station should include a Crystaloi as a standby. Type O $3.50 Mailing Weight One Pound

Dimensions, 239 "x 1 %" CRYSTALOI DETECTOR Type AA In the Type AA you have a supersensitive detector that has made a remarkable record. This type contains a stepped -up cohering inductance which causes it to be at least 2596 more sensitive than the Type O. It is a real beauty, will last a lifetime and is thoroughly guaranteed. You can't go wrong with this instrument.

Dimensions, 4 "x 3%" Type AA $6.00 Mailing Weight Two Pounds

TURNEY CONSTANT AMPLITUDE TEST BUZZER Over 12,000 Sold Non -resonant dilectric case, 500 -cycle tone, three binding- posts, beautifully finished and like all Turney apparatus, delivers the goods. Order one now and eliminate buzzer troubles. Dimensions, 214 "x2?;" Price $0.75 Mailing Weight One Pound NOTICE -Send five cents in stamps for our miniature catalog containing full information of the above instruments and other wireless goods

Third Avenue Eugene T. Turne y Company,COtll an , Inc., NEW YORK 'CITY

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMEN TER 597

QUESTION BOX. (Continued from page 595) The New up, thus decreasing the internal resistance We Announce which generates the power again. Q. 3. What is a hot wire ammeter used "ALBANY" for? A. 3. A hot wire ammeter is used for de- Alternating Current termining the amount of current generated in an oscillatory or other circuit. It reads Volt and Ampere Meters correctly on D.C. or A.C. circuits. Designed especially for the trans- BUZZER SHOCK. former primary circuits in Wireless (673.) A reader of Tuscaloosa, Ala., telegraphy. writes as follows: Plain Open Scale Q. 1. Explain how a bell or buzzer acts Black Figures on White Dial as an induction coil in that it gives a shock Heavy Beveled Glass when the grounded binding post and the Neat in Appearance adjusting screw are used as secondary ter- Finish -Nickel Front, with Black minals. Insulated Base, Back Connected. A. 1. The only way we can explain this Long Posts. is that, the sudden excitation and sharp Dimensions- Diameter of Base, 3 ". demagnetization of the magnet coils of the Front Diameter, 2% ". buzzer re- transforms the energy in it to Depth - I % ". pulsating current passing thru the hands Fully Guaranteed of the operator, thus causing the shock. The spark produced between the terminals PRICES of the vibrator at break, and the current VOLTMETERS -O to 125 Volts, A.C.-63 Cycles . $8.50 and voltage between them at a given time AMMETERS -O to 10 Amperes, A.C. -60 Cycles . $8.00 Postage Extra-Shipping Weight I Pound is very great ; in fact, the potential difference in certain cases, climbs as high as 100 Have You a Copy of Dur Catalog "E "? to 200 volts, depending upon the inductance of the magnet coils and the rapidity of MAGUIRE & SHOTTON break. The sudden counter electro-motive Albany, N. Y. force of the magnet coils discharges into the vibrator terminals and it is this that causes the shock to the operator. It is Two -Step Multi- Audi -Fone You don't know what wireless signals are Radio Code Teaching Circuit Comprising Ordi- nary Buzzer, Small Condenser and Phone until you have heard noticeable that the shock is not continuous, a Two -Step M A. F. but is a pulsating one, proving that the current produced at the two terminals is not continuous. When the armature closes the Multi- Audi -Fone - - - - $18.00 buzzer circuit the self- induction current due to the magnetic field is opposite in direc- With Special Head Set - - 23.00 tion to the magnetizing current. At "break" of the circuit the self- induction Pocket Wireless Receiving current is in the same direction as the bat- Se 5.75 tery current and adds to it. This latter induced current is of very high instan- M.A.F. Detector Stand - - 4.25 taneous value. - 2.00 Q. 2. How may a buzzer, telephone re- Price $75.00 M.A.F. Fixed Condenser ceiver, and battery be connected so that the Damped -Waver 45.00 & 100.00 sound of the buzzer is heard in the re- Un- ceiver, as in the wireless test buzzer? SEND FOR NEW CIRCULAR Detector Fone: - - - - 35.00 A. 2. The diagram herewith gives the connections of the apparatus you mention. 275 MORRIS AVENUE Q. 3. Will a 6 volt, 12 -15 watt bell -ring- ELIZABETH, N. J. ing transformer operate a spark coil made MULTI -AUDI -FONE to work on 2 -4 dry cells? Will the Erect- or toy step -down transformer? How is this calculated? A. 3. A 6 volt bell ringing transformer will operate a 1" spark coil. However, we New Undamped Wave Coupler No. 749 suggest that you should not use this ar- Special Introductory Price, $18.00 rangement as the vibrator the spark coil of Our new coupler No. 749 1832" long, 9" wide, and will not work steadily due to the alternat- 10" high, ove r all, and on an average -sized Antenna tunes to 15,010 meters. This coupler, used with the ing current operating the vibrator. It is new CHAMBERS' SYSTEM or CIR- impossible for us to give you the calcula- CUIT, will bring in signals from domestic and foreign Arc Stations surprisingly tions for this, as considerable data is re- loud and clear. Note the difference in quired on the dimensions of the transform- size of our No. 748 and No. 749. We claim to be the original inventors of er before we can give you the calculations. a SYSTEM or CIRCUIT for the receir tim of the undamped waves without the use of Loading Coils or Oscillating Coils. DENTISTS' AMALGAM. as they are sometimes called; as with our S!'STEM or CIRCUIT only two inductive) (674.) Huerton Bingham, of Gisborne, Coupled Coils are necessary. Circuit supplied N.Z., asks : T}ie CHAMBERS' CIRCUIT saves you money. 1. Think of itl No extra calls to pay for, and price of coupler only 18.00. Place order Q. Could you give me the substances now in on the introductory price. Order. filled Ìn rotation. Send for and method of making dentists' amalgam? 0 O to be I wish to make some for fixing crystals as F. B. CHAMBERS & CO., 2046 Arch St., Phila., Pa. it sets fairly hard? You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 598 THE ELECTRICAL EXPERIMENTER December, 1936

A. 1. The usual dentists' amalgam is made by dissolving chemically pure zinc metal dust in mercury. The zinc is placed in a glass receptacle and the mercury carefully poured over it. Only a few drops are necessary at first, until a thick mixture is obtained by the dissolved mercury and zinc. By adding more mercury the density of the mixture can be controlled. Q. 2. Why do signals with a crystal detector come in strong and then fade away and then regain normal strength, and with an Audion sometimes stop for a moment? A. 2. The phenomenon in your detectors BEACON ELECTRIC WORKS cannot be accounted for, except that it OF NATIONAL CARBON COMPANY may be due to the other apparatus you 132 -138 KING STREET. NEW YORK are using such as the aerial and loose coupler, variable condenser, etc. II -17 Sometimes a S.DESPLAINES ST.. CHICAGO 156 SECOND St. SANfANC)CO corroded or loose connection will give these BUY A peculiar operating characteristics in the re- BERZON AND BE GUIDED RIGHT' ceivers. Also on windy days, it may result from the swaying of the antenna. However, the main cause is generally from loose or unsoldered connections. We would, therefore, advise you to look over the connections and see that they are properly made with the instruments. If possible solder them to each individual instrument. Q. 3. Is the crystal "Radiocite" adver- tised by the Electro Importing Co., a natural or artificial substance? If natural, what is it? A. 3. "Radiocite" crystal is a combina- Experimenters' Library for $2.85 tion of a natural and artificial product, the UP -TO -DATE BOOKS BY P. E. EDELMAN HIGHLY RECOMMENDED BY EXPERTS formula of which is at the present time These elegant fully illustrated cloth bound books com- kept a secret, and it is the result of a great prise Edelmañ s "Experimental Wireless Stations, 1916 deal of research work on their part. edition" $ I.50 (formerly $2.00) the foremost radio book EXPERiMENTS that every BY enthusiast wants. and "Experiments" 1916 PHILIP E. EDELMAN edition, endorsed as one of the greatest works covering CONVERSION OF A.C. TO D.C. the wonders of modern science. I t is a book that shows (675.) Frank Stigliano, how to make mechanical, electrical and scientific devices. of Wilmington, $1.50. Either book may also be ordered separately. Del., asks the following: Q. 1. I would like to know if the A.C. Here Is an Appreciated Gift current can be changed to D.C. with the which will please a reader of this magazine better than mercury arc? anything else within ten times the price. A. 1. We would refer you to the Novem- Spacial: A limited number of leather bound, gold ber issue of THE ELECTRICAL EXPERIMENTER embossed, copies of "Experiments" may be had for only and in the "Question Box" thereof you will $3.00 each. a handsome gift indeed. Give him at least find complete description of a mercury one of these practical books ($1.50) or better still both tube (cloth. $2.85; or one leather, one cloth, $4.50) and be used for converting A.C. to D.C. assured you have done well. Direct orders bring prompt shipment. Satisfaction guaranteed. NOW! LIQUID RHEOSTAT. PHILIP E. EDELMAN, Publisher,'BAv St. Paul, Minn. (676.) Albert H. Beiler, New York City, wishes to know the following : Q. 1. Will you please advise me of a Arnold Navy Model Loose Coupler A customer said the other day: "Arnold, I have seen your Ad. in the magazine for Price $15.00 months and had I known the instrument was as good as it is and looked so much //o vo// /am,os better than the Cut I would have bought one sooner. I am glad I came to town and had a chance to take one in hand and see 38 vo// /a//7P % for myself." Needless to say he bought one. I also carry the finest line of Switches, Switch /10 V Points, Cabinets and Accessories on the market. 111111111 Send 2c stamp for Bulletin No. 3 Please Note NEW ADDRESS C76

J. F. ARNOLD, 327 East 119th Street, New York Hook -up for Balancing Up a Number of Low Voltage Lamps with a 110 -Volt Lamp Bank. WIRELESSi suitable formula for a liquid resistance to TRANSFORMERS be used as a rheostat and which will retain a constant resistance under all ordinary are enabling many amateurs to cover 700 conditions. I have tried carbon electrodes to 900 miles and come in strong while in salt water and HzSO. ; also various complying with_all government regula- other electrolytes, but all of these vary their tions. resistance when used for any length of time. I have heard that theaters use liquid Let us tell you how you can do part of the rheostats with great success, by using cer- work yourself and get one of these excellent tain secret formulae to make up their solu- transformers at á remarkably low cost. tions. Do you know of any solution that will solve this problem? jgaseirosk A. 1. There have been several formulae WARREN developed OHIO during the past for liquid rheostats and they depend entirely upon the Tgeym°Write Dept. EE amount of current which they are. to regu- (Continued on page óor) }"os benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER Wireless Apparatus of Known Quality MESCO Short Wave Regenerative Receiver Recommended for relay work on Will increase receiving range of any wave lengths of 180 to 450 meters. It station over 100 times. is possible to receive wave lengths up Complete in every detail and ready to 1,000 meters with reduced amplifi- for operation. when connected to an cation. aerial ground audion detector and tel- The circuit is the Armsti!ong regen- ephone receivers. erative with constants accurately A blue print of connections with calculated for the wave lengths when detailed instructions for setting up and employed in conjunction with audion operating this receiver is supplied with detectors. each instrument. Oak cabinet. Will receive undamped and damped The metal parts are of brass, nickel waves. No. 8467 MESCO Short Wave Regenerative polished. Receiver - Price $32.50

Intensifying Transformer Variable Condenser Universal Detector Stand reliable and scien- Remains permanently in adjustment. One of the Can be used with any crystal detector in connection Capacity .001 M. F. a thoroughly Stands made. with Audion. Signals can be intensified 10 to 25 times. tifically made instrument. most simple and effective Detector Price No. 224 Price $12.00 No. 294 Price $4.00 No. 248 $3.00

Wireless Key The last word in efficient wireless key construction. No. 452 -N. P. Lever Price $1.98 Fixed Receiving Condenser Wireless Practice Set' For stationary and portable outfits. Diem. 2 in. The most perfect set made. Equivalent to five Base removable and can be screwed to table. Large different sets. Supplied complete with Red Seal Dry capacity. Battery. No. 440. Price $0.83 No. 342 Price $2.07

Wireless Spark Coil Telephone Receivers Rotary Spark Gap on today. Best Very high grade. Can be used on 2000 miles. Ex- Will increase the efficiency of any Transmitting unquestionably the best the market 1000 ohms. coil to use on Dry Batteries as the consumption of tremely sensitive. Station 0 to 30 per cent. Has very high olear note. current is very low. Made in 34-in. to 4 -in. The 3 -in. No. 480 Price $6.00 Can be used on spe.rk coils or transformers up to and 4 -in. supplied with separate primary condenser. 1 k.w. capacity. No. 495 -3 -in Price $21.00 No. 222-6v Price $12.00 No. 496 -4 -in Price $34.80 No. 223 -110v Price $13.00 Send 10c. for New Wireless Manual A 9 The most complete book of its kind published. You cannot possibly afford not to have one. Contains 180 pages. Send for one NOW. YOU WILL GET YOUR 10 CENTS BACK ON AN ORDER FOR $1.00 Our Pocket Electrical Catalogue W28, 248 pages, mailed on request. This catalogue contains practically everything in general use in the electrical line and is in fact a small pocket encyclopedia of electrical goods information.

17 Park Place - New York 1106 Pine Street St. Louis 114 S. 5th Avenue - Chicago MANHATTAN ELECTRICAL SUPPLY CO s 604 Mission St:, San Francisco

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. boo THE ELECTRICAL EXPERIMENTER December, 1916

Z?o Eloctro -Sot (Zs. FI1ff HANDY BOOK EE i 71(1 CATA LO G U E EDITION B-2 ..EI.ECi PIC Ai. rtiiN0.5 This Electrical FOI EVErYBGDY for Electrical

'The Electro - set Co. Handy Book LoadorNows Bldg. Clovoland O. Price 25 cents and Wireless and Catalog Experimenters With each copy, the splendid 16 -page booklet "The Story of the `Red Head' FREE Receivers," describing the finest Wireless Telegraph Receivers made, sell - ing at only $5. 00. also, our monthly bargain -bulletin and our big book and game -folder, describ- FREE ing books at the lowest prices sold today. WORTH 25 CENTS TO ANYBODY This is the BIG BOOK you need and want. Describing positively the finest and most complete line of wireless, novelty, and experimental goods ever listed in any catalogue and containing, besides, innumerable tables, hook -ups and treatises of inestimable value to the experimenter. By actual comparison, the Electro-Set Co.s Handy Book contains more information than any two twenty -five cent books on the market. The Handy Book cost $9000.00 to compile. For RED HEAD WIRELESS RECEIVERS a limited time we will send this big, valuable book to those THE LAST WORD IN SENSITIVENESS in- By actual test they are from 10 to 27 points terested absolutely free of charge. Don't even send us postage. more sensitive than any other standard make. A great New York Testing Engineer reports Just write your name and address plainly on a post card, say highly in favor of Red Head Receivers. You take "I'm interested in your goods." no risk! 5 days' trial -and then if they do not fill every expectation we send your money back. THIS IS THE MOST INTERESTING CATALOG PUBLISHED PRICES 2000 ohms, per pair, complete set, with Every experimenter and electrically interested person should send for it head band and cord $5.00 today, without fail. We reserve the right to withdraw this offer at 1000 ohms, single receiver only 1.75 any time. 1000 ohms, single set, with cord and band 3.00 Send for ourfree Booklet before buying A Few of the Interesting Items wireless receivers You Will Find in the Handy Book Treatises on Wireless Telegraphy; Simple Electric Measurements; A.B.C. of Electricity with many fascinating experiments; Construction of Aerials. How Ito Make Selenium Cells; Calculate Wave Lengths; BIG TRIAL OFFER and Code Charts. To "Experimenter" Readers For the purpose of further introducing Tables and Data on Transmitting Ranges; Spark Voltages; Indue- our already widely known super- sensi- tivity; Weights and Measures; Wave Lengths; Specific Gravity; Resis- tive Triple A Grade Wireless Min- tance; Wire Data; and Spark Coil Construction erals, we offer for a limited time only this trial size package of A A A HEADQUARTERS FOR WIRELESS GOODS an:g4a ree GALENA world re- Big Values at Low Prices in Wireless Goods, Motors, Flash - ceipt of Inc in stamps or Coin lights, Novelties, Parts, Raw Materials, Wire, Heating Appliances, Nearly all serious wire- Send today for this trial package Lighting Plants, Toys, Train Sets and other goods. Read about our less experimenters are of Famous Electroset Galena. If "Red- Head" Wireless Receivers Audion familiar with our won- you do not find more sensitive Detectors derful wireless minerals. spots in this small trial 1-6 K. W. Wireless Transformer Storage Batteries Hundreds of testi- package than you can get out $1.00 Telegraph Set Raw Materials monials prove our con- of 8 oz. of ordinary galena, we tention that no min- will gladly return your dime. $1.00 Electrical Outfit finding Posts erals marketed today $4.00 Professional Tuner Experimental Goods can compare in sen- NOTE: Do not confuse this offer sitiveness to our with our regular Arlington Tested Send the Post Card TODAY standardized grades. Individually Packed Galena at 25e We make an unlimited postpaid. Arlington Tested Gal- guarantee that obviates ena will be sent if requestedjupon all risk -Your money receipt of 25c in stamps or coin. THE ELECTRO -SET CO. Arlington Galena is Individually back if you are not tested for extreme distances and is ADDRESS DEPT. E -7 CLEVELAND, OHIO satisfied. ultra-super-sensitive ELECTRICAL THINGS FOR EVERYBODY Send For The Bargain Trial Galena Today

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 6oi

QUESTION BOX. (Continued from page 598) late. For small currents say up to 2 K. W. 14" of consumption by the apparatus, the electrolyte of the rheostat should be made of ordinary salt or sodium chlorid. In larger rheostats, the electrolyte used is a solution of either sulfuric acid or nitric acid. The density of the solution depends entirely upon the character of work for which the rheostat is used. The density averages in the neighborhood of 10% of acid to 90% CYCLOPEDIA- CYCLOPEDIA CYCdDPEDIA CYCLOPEDIA CYCLOPEDIA :YCIOPEDIA CYCíA m= of water. This proportion is universally vf V et. if V 1, vr , employed where fine regulation of current APPLIED APPIlFD APPLIED APP 7; is required. ..,.1 There are no secret formulae for solu- EL cfCrx- fIECIRICrfY r tions used in liquid rheostats to our knowledge, and the ones above mentioned are VOLI VOLE and very those which are used generally ELEMENTS - DYNAMOS extensively in laboratory work. mom/nuts PRINCIPLES Q. 2. Do you know of any way in which ¿ uinNENrs CALCULATION METER DESIGN a 110 volt D.C. may be used so that any number of small 3.8 volt lamps in parallel may be operated successfully by using a 40 or 60 watt lamp in series with the parallel combination. When about 30 small lamps are connected in parallel, the amperage of the resistance lamp is not enough to supply all of the small ones. Connecting them in series directly on a 110 volt line AN{WCAN ANCRICAN AMr.RICAN the problem, but for the r,CIMICAt.: will partially solve RCaNiCK . ITCNNICY." TFCNNICM. purposes required, a series connection is SoCRTr`<. sot. impractical. A. 2. The only way in which you can operate 3.8 lamps on 110 volt circuit is to employ a suitable resistance in series with the line, thus reducing the voltage of 110 volts to that of the voltage required by the Send No Money lamps. If a resistance is not at hand, it is ad- USE THESE ELECTRICAL BOOKS SEVEN DAYS AT OUR EXPENSE visable to connect a bank of two or three connected on par- By merely filling in and mailing the coupon below you (tan get this complete set of the 110 volt, 60 watt lamps before allel in series with the line, thus making Cyclopedia of Applied Electricity on trial. Use these books for seven full days resistance and thereby re- you make up your mind whether or not you want them. If you keep them, you may up the necessary installments of $2.00 a month. If you don't ducing the voltage to that required. It is pay the special advertising price in easy that a variable resist- want them, you may send them back at our expense and you won't be out a penny. advisable, however, shipping charges both ways. ance be used in the line as the proper volt- Remember, we pay the age can then be obtained by merely chang- ELECTRICAL LIBRARY HANDBOOKS ing the resistance of the rheostat. A MASSIVE -NOT You should connect the lamps as indi- These seven splendid volumes contain all the knowledge you need in order to earn big cated in the diagram. money in the electrical field. They are not thin handbooks, but thick, encyclopedia-size volumes, handsomely bound in half red mMorocco leather, gold stamped. Each one CONDUCTORS FOR CONNECTING measures 7 by 10 inches, and is 2 inches thick. RADIO INSTRUMENTS. This big size permits the use of large and comprehensive illustrations, plates, diagrams, in the Cyclopedia's 3,500 pages. (677.) Lewis J. Cissna, writes as fol- etc. Over 3,000 cuts are contained to lows : The completeness of the Cyclopedia will be a revelation Read These Subjects Q. 1. Will shellac injure or short -circuit you. Everything electrical is explained in plain, simple Elements of Electricity coil or tuner composed of enamel English technical point is made clear. Each volume Electrical Measurements- a loading -every -Underwriters' Require- wire if it is put on it to hold it firm on is carefully cross -indexed for instant reference. ments-Theory, Calcula- cylinder? tion, Design and Con- the For this sum insignificant struction of Generators A. 1. Shellac will not injure or short - -an and Motors - Dynamo- of the loading coil. How- 50c a Week one -this wealth of electrical Electric Machinery- circuit the turns us a penny Lighting Machinery - ever, it has been found that cheap shellacs information is yours. But you don't have to send Power Transmission - until you have used the books for seven days. Then, if you Electric Railways-Power have the property of absorbing moisture, Stations - Switchboards the conductivity between the decide to keep them, send only $2.00 a month -50c a week - and Switching-St orage thus increasing price of $19.80 has been paid. Batteries -Applied Else- additional turns and thereby reducing until the special advertising ire-chemistry Electric The regular price of these pay- raising books is $35.00. Elevators -Electric- Weld- somewhat the inductance of the complete ing and Heating- Wire unit in all around work. Shellac and all and Wireless Telegraphy. other varnishes tend to increase the dis- Consulting Service Free tributed capacity effect and are best dis- in the American Technical loss A year's Consulting Membership penst with. However, the amount of Society-regular price $12.00-will be included with all orders American Technical Society obtained by the use of shellac is, generally for a limited time. The advice of an entire corps of glee- Dept. E7449 Chicago, U.S.A. speaking. negligible. For accurate work, trical experts is yours to help you in your progress-for a Please send me the Cyclopedia should be wound on a threaded of Applied Electricity for seven the wire whole Yyear FREE! days' free examination. If I de- form without the use of shellac. cide to buy, I will send you $2.00 Q. 2. What kind of wire is the best for No Money the Coupon connecting up radio instruments for send- Send -Just thein seerate oas, anathe olan eat buy. Remem- Then you will ing and receiving? See these books for yourself before you sear oe as rebeen show A. 2. The receiving apparatus should be you don't risk a penny or assume a single ob- set of hooka and the $12.00 consulting connected with flexible stranded conduct- ligation. The books will be sent by prepaid - express memberahi are mine and fully paid for. should be properly boundaries of the United along without ors and all connections to anyone within the the b okay Ì g11 return them soldered to the various instruments. States or Canada, and they may be returned at ' days, at you expense. apparatus should also our expense if they fail to please. But you must act now ! The transmitting This generous offer cannot be continued indefinitely. 7 be connected with stranded conductors of Send the coupon now. A"ame. considerably larger diameter than that used in receiving. Also, the insulation should AMERICAN TECHNICAL SOCIETY is Address. be of such thickness that no leakage ap- Dept. E7449 CHICAGO, U.S.A. parent when the transmitter is in opera - (Continued on page 603) I Reference Vnu b -nett by mentioning "The Electrical Experimenter" when writing to advertisers. THE ELECTRICAL EXPERIMENTER December, 1916

IIINS IIII 11I11 . II . I II LVll. IIJIII IIII I VIIIII VII I, IN u ll6 VI IIJ IIII JIIILI6 . IIIIIII , l l,III III i,,i_ . .IIIII 1111111 J IJI . i IIII IIIIIII 11111 IIIIIIIIi INIIIIIIIIIIIIIIININI Iii INIIIIIIINIIIIIIIIIIINIINNNIIIIImININIIIIIIIIIINi IINIIIIILo M

The Most Sensational Announcement in the Field of Wireless Introducing Tigerman co miire The most efficient, dependable and supersensitive wireless detector science has produced. Its introduction opens a new era in the field of wireless.

Patents' Pending

The following are only a few of the uses incorporated in this one instrument: Super- Sensitive Detector. By employing either end of the tube. Detector and By employing both ends of tube, using one end as a detector and the other One Step end as an amplifier. This arrangement besides increasing the receiving range to an almost wonderful degree enables the operator to hear weak signals which Amplifier are impossible of reception without it. Detector and By wiring up one end for the reception of damped waves and the opposite end Oscillator of the tube for undamped waves, rendering your set serviceable for the reception of both mentioned waves by a mere turn of a switch. It can also be used in numerous other hook ups employing the use of two ordinary vacuum detectors.

THE . TIGERMAN DETECTO-AMPLIFIER is an entirely new invention embodying new features of great importance that are not found in any other vacuum detector thereby making it unquestionably superior to any in its sensitiveness, efficiency and stability. It infringes on no patent. One of the most valuable features of this new invention is that static interference is reduced to the minimum. It therefore enables the reception of signals with utmost clearness even on nights of heavy static. Can you imagine all the despicable nuisance it eliminates? It would be folly for anyone to buy an inferior obsolete detector when this new TIGERMAN DETECTO- AMPLIFIER can be bought for just a trifle amount more and get DOUBLE LIFE- DOUBLE SERVICE -DOUBLE SENSITIVENESS and DOUBLE EFFICIENCY. The Introductory Price is only $7.00 AN UNUSUAL OPPORTUNITY awaits those who have already got any kind of a vacuum detector by obtaining our attractive proposition to exchange your old obsolete detector for one of these remarkable TIGERMAN DETECTO-AMPLIFIERS. This splendid proposition is made for the purpose of standardizing the TIGERMAN DETECTO-AMPLIFIER and we are confident that on account of its supreme merits it will soon completely revolutionize the wireless field. This offer is only for a limited time and it will require quick action to take advantage of it. Get busy, right now and write "Please send me your Special Proposition." Our illustrated booklet mailed free on request. Send for one. National Electric Manufacturing Co. 5 So. Wabash Avenue Chicago, Illinois

- 01I u NIA

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 603

QUESTION BOX. (Continued from page 601) tion. Modern transmitters employ ordinary copper strip connections which are not insulated, in the true sense of the word, but they are insulated from surrounding objects when they are used in the station. Q. 3. Would lightning be apt to hit my lead -in wire which is 35 feet long and composed of No. 18 B. & S. gage wire? A. 3. It is impossible to say whether the STOP / "4:I lightning will hit your lead -in as the freak- LOOK tt ish phenomena of lightning are such that it is impossible to foretell the dangerous ef- LISTEN, fects that lightning may have. In order to properly guard against it'you should al- ÿ we ways use a lightning switch in your station. .. ß 9 ¡i sm6BB6ci uióaB e BOOSTERS AND WIRING SYSTEMS. -'_-,41 was ..V,- ..- (678.) John Shelly of St. Louis, Mo., 4 L.-.J L -. - .,,- asks: Q. 1. Explain the use of a booster? "TUST one long thrill of joy!" That's what one A. 1. When a number of feeders run out J boy calls his Lionel train. It runs so steadily - from a station, the longest and those carry- hugs the rails so firmly-and is :o like the big, real ing the heaviest loads will have so much trains -you almost expect to srte a good- natured drop on the line that the pressure at dis- from between tant points is too low. It is, therefore, porter thrusting his kinky head out necessary to raise the pressure to compen- the cars as they dash past! sate for the voltage drop and this is done by inserting a booster in the circuit. Q. 2. Is a three wire system desirable with an isolated plant? A. 2. It is more expensive to install than EIECJPIC the two wire system as it is necessary to add a balancer in connection with a 240 volt dynamo. This balancer set should Lionel Electric Trains run on batteries, or very economically have about one -tenth the capacity of the .on house circuit with a Lionel "Multi%olt Toy Transformer." plant. Such an equipment has its advan- Absolutely safe -can't shock you. Built of high grade steel tages when 240 volt motors and 120 volt (not brittle cast iron) and won't break. Hand -painted lamps are connected to the system. With with real gold and bright, non -chipping zolors. motors are this plant no changes in the a Boys! necessary, whereas in a straight 120 volt A Pippin of Catalog, J. LIONEL COWEN, Pres. locomotives, the many system, the motors would have to be Just out, describes all the LIONEL MFG. CO. passenger, freight and street cars. switches, sema- changed from 240 to 120 volt machines. THE phores, everything. Also a trip through the won- 48L E. 21st St. derful Lionel factory. Free -send for it, then TELEPHONE CONNECTION. NewYork, N.Y., order from your dealer. (679.) Russel E. Bathrick, Minneapolis, Minn., wishes to know : SHOW YOUR FRIEND -Make your awn "Wireless," also Dynamos, Bah PAGE 621 Series, Motors, Telegraph,..Telephone, Lights, Bells. i a Alarms, Coils, Current Reverser, Electric Engines, etc. Bank with 75 llustrations; by experts so anyone earl Look at it yourself-NOW ! un4oretand It With Catalog. Agg 1Oca3 for 2561.p r J. C. DONN,70551. Dearborn St., Dept. 118, Chicago. Ill. 111111111,,,,1eeem11a,,,n11,m1e,11n,,, :1111111,11,,,,,111111e1111 1 111 1a1e111e, 111e 1e, eep1, e,,,,,, , 1,,,, 11111111111111, 1n,, 111 , ,11.01111111e1111a,e1111

1 oG7s

Talking Circuits for Two -Party Telephone Line with Induction Coils. EXPEFUMENTERS!

Q. 1. Would like to have a hook -up for Save money by buying a a two -party telephone line. GOOD storage buttery FIRST. The ONE Marko A. 1. Wiring diagram of a two -party th ng (V telephone line is given herewith. you can't afford to Storage Q. 2. How many dry cells will it require? experiment w i t h Batteries are A. 2. Four dry cells. is a storage especially adapt - battery. Q7ÿ ed for operation of RADIO TRANSMITTER QUERY. all kinds of spark coils, 6WT8 insuring a heavy and (680.) W. J. Murrow, Savannah, Ga., powerful spark. There is asks the following: nothing, superior Q. 1. What would be the transmitting Marko GUARANTEED range of a station using a 12" spark coil Storage Batteries are FOR AUDION USE 1 K.W. open -core transformer, both or a It is a well -kncwn fact among up -to- of Chambers make, with an aerial 100 feet not experiments - condenser, they have been date wireless engineers and experi- high and 300 feet long, with menters that the Audion operates at etc., at this place. on the mar- o when a higher efficiency A. 1. You should have no trouble in ket for 10 controlled by a storage bat- 150 miles with a 12" coil or a tery that gives constant voltage. transmitting years. Marko Batteries are designed to 1 K.W. Transformer with the aerial which meet these conditions. you mention in your letter under good at- Guaranteed highest quality and L "welt prices. Some Popular Sizes. mospheric conditions. Type Volts Amp. H.R List Special price to Q. 2. is required for a receiving Ca40city c0e0 rirele$4.2gineern What 4C2 4 3 7 set and a transmitting set to receive about 6C2 6 40 10.00 6.00 6C4 6 60 ' 12.00 7.20 5,000 miles and to transmit 1,000 miles? 6C6 6 80 16.00 9.60 What instruments are required? MARK O' QUALITY A. 2. To receive 5,000 miles you should PAUL M. MARKO, 1191 Bedford Ave., Brooklyn, N. Y. The Mark -o' Quality employ the following instruments :- Loose New York Depot-974 8th Ave., New Yort City Coupler, two variable condensers, fixt (Continued on page 6o5) You benefit by mentioning "The Electrical Experimenter when writing to advertisers. (J04 THE ELECTRICAL EXPERIMENTER December, 1916

I READ THESE LETTERS ABOUT THE RADIO HEAD

Strength and Tone SET THEY ALL LIKE BEST I3attle Creek, Mich. I received your phones They are samples of the letters we are receiving constantly from and will say that I have wireless operators everywhere -both amateurs and professionals. found them all you claim. Have worked them along Many of them are experts who have tested different makes against with phones costing con- each other before making their decision. All agree that for strength, siderably more and found quality of tone, and ability to bring in weak signals sharp and clear, that they excelled in both loudness and tone. they have yet to find the equal of the (Name on Request) Stromberg -Carlson Increased Audibility Pittsburg, Pa. RADIO HEAD SET I had a well -known make Our new Improved Type A -9723 is wound to 2000 ohms, and fur- in my station previous nished with drawn aluminum receiver cases, german silver head to this purchase and thought I was getting bands with universal ball-joint adjustment, waterproof cord and strong signals. I was laminated pole pieces. Clearer Signals greatly mistaken, and find your phone Increase at your dealer or Alameda, Cal. the audibility twofold. direct from us Your receivers have been (Name on Request) Price $8.25 tested out against other TEN DAY TRIAL OFFER: We sell this beautiful instrument with the un- makes, and prove to be derstanding it will increase the receiving efficiency of your station regardless the best by far. Signals of the make of Head Set you are now using. If at the end of Ten Days it which are hardly audible has not done so, or if you are in any way dissatisfied, send it back and we in other makes come in will refund your money immediately and without question. This ten day fine and clear in yours, Trial Offer applies whether you buy from your dealer or direct from us. and I now hear many stations which I never heard Send for Bulletin No. 1006 -C giving full description. before. STROMBERG - CARLSON TELEPHONE MFG. CO. (Name on Request) 1050 University Ave. Rochester, N. Y.

JpERtO MIGNON iRcÁó sTE s SYSTEM s Asr

THE LAST WORD IN RADIO ENGINEERING Mignon Adjustable Disc Core Undamped Wave Receivers RW 1, RW2 and RW3 THESE RW TYPES (latest Mignon invention) are entering a new field in Radio Engineering, eliminating the so familiar Loose Couplers and Loading Coils. These late types introduce adjustable special metal disc cores, heretofore considered absolutely impossible. These new undamped wave receivers are the most efficient apparatus constructed at the present time, regardless of price and manufacture. Write for Catalog R7 and mention E. Ex. ELMRS,A ,Y, MIGNON WIRELESS CORPORATION,

Yon benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 6o5 December, 1916 THE ELECTRICAL EXPERIMENTER

QUESTION BOX. to THERE'S MONEY IN IT" (Continued from page 603) condenser vacuum detector, vacuum ampli- =LEARN TELEGRAPHY-qig_ fier, 3,000 ohm 'phones, loading coil and a =ÑMme- large antenna which may consist of a sin- -=_MORSE AND WIRELESS=:-_____- gle wire 600 feet long and about 75 feet high. You should have no trouble then in receiving stations 5,000 miles away from TEACH YOURSELF your station. in half usual time, trifling cost, with 5 is nec- the at the About a to 7 K.W. Transformer wonderful Automatic Transmitter, THE OMhIGRAPH. essary to cover the range which you desire Sends unlimited Morse or Continenta messages, at to transmit. In addition to the transform- any speed, just as an export operator woulc. is neçessary to employ the er of course it Adopted by U S. Gov't. 4 styles. Catalogue free. regular high -class auxiliary apparatus such as high tension condensers, oscillation OMNIGRAPH MFG. CO. transformers, etc., in connection with a 39L Cortlandt St. New York suitable antenna in order to obtain maximum results. It is very important to have the sets tuned properly so that a maximum radiation should be obtained from the antenna. Q. 3. What would be the receiving length or range of a set of wireless instruments with the aerial length and height as above with an Audion detector and amplifier combined, using storage batteries of the proper voltage for the detector and with a 15,000 meter wave tuner, a good pair of 'phones, etc. A. 3. You should be able to receive 3,000 miles with the apparatus you mention and with the aerial cited. RADIO CURRENT FORMULA. (681.) Alex. Jablonsky, Keokuk, Iowa, wishes to know : Q. 1. Give me a formula for calculating the amount of current, Ie which the transmitter needs to generate to give a certain amount of current Ir in the receiving station. A. 1. The formula herewith given is the one you should employ. hZ (feet) 1 .088 d Ir = - L 10ea (meters)Xd (miles) It is founded on the researches of Dr. W. L. Austin. Later this formula has been modified by Kimura. It is this formula that we give instead of Austin's, as it is U00'r ,...,,,, ;:51 somewhat simpler to use in calculating the complete equation. Q. 2. Also give me formula for obtain- Control the Cash Register ing the amount of radiation from a given station. A. 2. We would advise you to refer to of a Billion Dollar Business! the "Radio Section" of our November issue for data on this formula as an extensive EN ARE NEEDED to watch the proshts of the article was published in that issue describ- Electrical Industry. These men must be trained -and if they ing it quite fully. are, big salaries will be paid to them. Electricity cannot be so d over the counter like ordinary merchandise. It must be measured PROTECTIVE RELAY OPERATION. by delicate meters -and the men who know meters and their opera- (682.) Jack Adonis, Saratoga, N.Y., tion are in big demand. wishes to know how protective relays operate. Big Salaries Must Be Paid A. 1, They act in combination with auto - matic circuit breakers, operating when their The Electrical Industry cannot afford to risk the care predetermined setting has been reached, en- of its meters to untrained men. They pay big money to the man ergizing the trip coil of the circuit breaker who know. These men must direct the staff of meter men -they and thus opening the circuit. rule supreme over the profits of a billion dollar business. No wonder their salaries are large. No wonder $150 a month is ordinary. RADIO CONNECTIONS. Trained men are needed this (683.) R. H. Buvick, Atlanta, Ga., asks: Men Are Needed very hour to guard the profits of Q. 1. Please publish a diagram showing the Electrical Industry. Meter Engineers-the men who know the science of elec- the method of connecting the following in- trical measuring instruments -are in big demand all over America. And you can Fort Wayne struments for the reception of undamped qualify yourself to fill one of these positions. Just the kind of training you need may be yours right in your own home and by spending a few hours in pleasant Correspondence waves : -1 RJ8 Audion detector with tubu- reading and experiment, fit yourself for one ofr these big jobs. Write a' once -now. School lar bulb, 1 -4000 meter receiving transform- Dept. 7449 Fort Wayne, Ind. er, 1 long wave loading inductance and 2 Gentlemen: age send me your variable condensers. I should like to avoid Send the Coupon new book on Electrical Meter En- gineering, absolutely free and pre - if possible changing the internal connec- t paid. Also tell me how I can Bt Put your name and address on the coupon, or on a letter or myself to "control the cash register tions of the Audion detector. a post card now and get our new book on Electrical Meter Engineering I A a billion dollar business." It is A. 1. Diagram herewith gives the cdn- absolutely free. Find out about the opportunities that await you. Find distinctly understood that I am un- out how you can get this training right in your own home during your / der no obligations. nections of the instruments you mention in spare time. The book is free. No obligations. Write for it today. your letter. Opportunity is calling you and saying "Send the coupon." / Q. 2. My antenna is situated on the roof ' Name of a ten -story hotel. What would be the Fort Wayne Correspondence School Addreee safest and best way to ground it? 7449 A. 2. The best way you can ground your Dept. Fort Wayne, Ind. antenna is to connect the lead -in with a

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 6o6 THE ELECTRICAL EXPERIMENTER December, 1916

100 ampere knife switch, the ground lead STANDARD RADIO TERMS of which should be made of No. 4 B. & DEFINED. S. copper wire lead to the ground. This Approved by the Institute of Radio is the only way which you can ground it Engineers. if you desire to have it passed by the Under this head we will define the most im- Board of Fire Underwriters' inspectors. portant radio terms each month. Save them and by pasting each in a book (properly indexed) you Q. 3. I have a 4,000 meter loose coupler. will have a handy radio dictionary. Would it be necessary to load both the primary and secondary in order to receive 1005. (b) An auxiliary ship station. Storage batteries are charged from the ship's. long undamped waves? mains, and operate a motor generator A. 3. You should invariably use loading set or an induction coil. The over -all efficiency coils for both primary and secondary of is the ratio of the kilowatt - hours supplied to the storage battery for a full charge to the kilowatt -hours delivered by the antenna circuit during the complete time of discharge. The energy ratio, rather than the power ratio, is here required, because of the method of storing energy in such batteries. It may be conveniently measured by the ratio of (kilowatt -hours on discharge of the storage battery to kilowatt -hours on charge) multiplied by the ratio of (power delivered in the antenna to power supplied by the storage battery to the radio equipment). This method is closely approximate. 1006. (c) A land station. High voltage alternating current (2,200 volts, for example) is supplied to the station from local power mains. This is stepped down to operate a motor generator set which supplies current of the definite type desired for the station. The over -all ef- Connection for Vacuum Tube Detector Used for ficiency is the ratio of the power output Receiving Undamped Wave Radio Signals. of the antenna to the power supplied to the motor generator. If the step - down transformer feeds other electrical You Need aGood your loose coupler in order to receive long machinery or apparatus not a part of the radio equipment (e. g., lamps), the waves from undamped wave transmitters. power supplied to such apparatus shall be subtracted from the total power supplied by the step -down transformer Flashlight RADIO INQUIRIES. when calculating the over -all efficiency. (684.) G. H. Harris, Macon, Ga., in- If the motor generator in question is Along used to charge storage batteries which poorly lit streets, in dark quires: operate the station, an energy ratio, hallways, or gloomy corners, -a Q. 1. Does a wireless station have to be somewhat as in case (b) above, must inspected by a Radio Inspector and a Fire be taken instead of the power ratio. safe, 1007. (cl) A land station. A large steam engine sure, steady stream of brill- Insurance Inspector? operates directly or indirectly an audio iant white light is mighty handy. A. 1. It is advisable that the Radio and or radio frequency alternator which Fire Inspectors inspect your station, so that supplies current to the radio station exclusively. The over -all efficiency is the if any trouble arises later on, you are pro- ratio of the power output in the an- With a FRANCO Flashlight and tected. The law, however, does not require tenna to the brake kilowatts of the an inspection. engine driving the alternator. a Radio Battery, there's no dan- 1008. (e) Q. 2. If it does, A land station. A steam or gasoline ger of starting how should you go about engine drives a high voltage direct cur- fires, blowing up it ? rent generator which feeds directly or or blowing out you get real A. 2. You should write to both the Fire indirectly arcs or special gap discharg- - and Radio ers in the station. The ratio of the an- flashlight efficiency. Inspectors asking them to call tenna power to the brake kilowatts of to inspect your station. They will undoubt- the engine is the over -all efficiency (un- edly come and look der similar conditions to those of (c) the station over and above). advise you as to the different changes 1009. The rower output shall be taken as the Franco ! Flashlights which may be necessary. product of the total effective 'resistance BCD¡ of the antenna (not including the resistance of inductance coils, series an- INDUCTANCE. tenna capacity, or switches and other and Radio Batteries are all de- equipment in the antenna), into the (685.) John Gorman, Kankakee, Ill., square of the current measured at a finitely guaranteed. Made in asks: potential node. Q. 1. Please give me an accurate formula 1010. Standard Antennas. Two standard anten- seventy -five styles - you are for calculating inductances. nas are proposed; one for ships carrying sets of 2.5 kilowatts or under, and bound to like some of them. Send A. 1. The formula you should use is the one for ships carrying sets of 2.5 kilowatts but not greater than 5 kilowatts. for one developed by Nagaoki. This involves illustrated booklet and name a factor which depends upon the length 1011. (a) SMALL ANTENNAS of nearest dealer. and diameter of the coil Capacity=0.001 microfarad Inductance and the ratio "co- =50 microhenrys efficient" values of which are taken from Standard Test Wave Length =600 meters tables. We are unable to give this matter Test Wave Antenna Interstate Electric Novelty Co. here due to its length and complexity. We Length Resistance *300 meters 8 ohms 104.14 S. 4th Street Brooklyn, N. Y. would advise that you watch our forthcom- 600 meters 4 ohms ing issues for complete details of the for- 1200 meters 3 ohms mulae for the measurement and calculation 1800 meters 4 ohms of inductances which we know will be of 1012. (b) LARGE ANTENNAS great service to you in the work you are Capacity=0.002 microfarad Inductance= pursuing. 30 microhenrys Detectagraph SPECIAL Standard Test Wave Length=600 meters OFFER Q. 2. What do you consider in figuring Test Wave Antenna the efficiency of a rotary converter? Length Resistance $12 A. 2. The efficiency 1600 meters 4 ohms of a rotary converter 1200 meters 3 ohms depends entirely upon its size. In larger 1800 meters 3 ohms machines the efficiency is greater than that 2400 meters 4 ohms 3000 meters 5 ohms of smaller units. However, they range *At 300 meters a suitable series condenser will about 75 to 80% in machines up to 5 K.W. be inserted in the antenna circuit. The resistance and less in machines of smaller size. of this condenser will not be included in the antenna resistance, since this condenser should be supplied with, and forms part of, the transmitting CABLE TO NANTUCKET. set. #See note referring to 300 meters, above. Our famous Micropho- Detectagraph in now offered at an extremely A telephone cable was recently laid below D This detecting instrument of marvelous sensitivity can be used for detecting secret conversation.. tween the mainland and Nantucket by the MARCONI NAVAL CAPTAIN NOW. Outfit consists of Sensitive Transmitter and connector, 25 -ft. Black Cord Receiver, Headband Case and Battery. The Transmitter Western Union steamer Robert C. Clowry. Guglielmo Marconi, the inventor, has only two ounces. Price complete $12.00 for a limited num- bei hs This cable will enable the residents of Nan- been transferred from the engineer corps MICROPRO.I/ETEOTOR COMPANY gaSton Botssonnault, Pres. 119-121 Nassau St., A. Y. C. tucket to converse with any part of the and appointed temporary captain of the Makers of Detecting Apparatus from $12.00 to $250.00 country by long distance service. navy. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 607 AMPLITRON New Vacuum Detector- Amplifier -oscillator Designed By AudioTron Engineers Special Introductory Price $5.25 More Powerful Amplifier, More Persistent Oscillator than the AudioTron This detector is of the two- member external control type and was originated by AudioTron Engineers last April. I t has been developed and greatly improved since that date. This is its first public offering. AUDIO TRON ALWAYS OFFERS GREATEST MONEY VALUE WHEN YOU BUY ON SPECIFICATION NOT ON INDEFINITE DESCRIPTIONS

AUDIO TRON No. 1 Junior Receiving Panel Orders mailed not later than December 10th will be shipped at these Special Prices:

Maple Panel finished in black No. 1 B Panel, Tube and imitation Bakelite., Potentiome- 30 cell sealed B battery $14.85 No. 1 A Panel and Tube 10.50 ter Control. All metal parts nick- No. 1 Panel only .. 7.00 eled. Double Cut -Out Switch. Parts for Panel only.... 5.00 Genuine double filament tested AudioTron. Fully Guaranteed Shipped prepaid when cash Brackets for Table Mounting accompanies order.

This High Grade Navy Coupler -$14.90 Delivered Free -on orders mailed before Dec. 10th Quarter sawed oak, base and Navy type bearing switches. Large primary ends. Secondary end, knots. Fiber tribes, lathe cut. No primary panel and guide sup- enameled wire used. Windings covered with celluloid. Double guide port hard rubber. rods. Metal parts nickeled. Tunes to 3000 meters. AUDIO TRON Navy TSroe Coupler, $17.50 2.50 AUDIOTRON 15000 M. ULTRA LOOSE COUPLER $32.50 Special Introductory Price on orders mailed before December 10th.

Embodies best features of commercial engineering practice. Quarter sawed oak base and primary ends, secondary end, primary panel and guide support hard rubber. Lathe -turned fiber tubes. No enameled wire used. 16 taps on secondary, 32 on primary. Navy bearing type switches. Large knobs. All metal parts nickeled. Windings covered with black celluloid, gives rich appearance and insures protection. Length overall, 36 ". Primary ends, 11' square. Double secondary guide rods. Guaranteed to tune to 15,000 M. The only high -grade long -wave coupler at any price. Regular price $37.50.

TERMS: Free Delivery where cash accompanies order. Satisfaction guaranteed. AUDIO TRON SALES CO., 315 Lick Building, San Francisco, Cal.

You benefit by mentioning "The Electrical Experimenter" when writing to adverters. 6o8 THE ELECTRICAL EXPERIMENTER December, 1916 The Moorhead Tube Patent Pending

IS your detector perfect? Do you copy the German stations in daylight? Are you receiving signals from enormous distances? Does your detector keep its supersensitive adjustment? Is it constant month after month? Do you copy the most distant signals through the heaviest strays and static? Is it the MOST SENSITIVE detector you have ever used? IF SO, you must be using the MOORHEAD TUBE. For this detector is guaranteed to do all of the above and more too. It oscillates, it detects, it amplifies. And does all three better than any device you have ever used. Operative in any circuit. Reduces static over 50 %, and has a life of over 1200 hours. THIS IS OUR ABSOLUTE GUARANTEE At a special introductory price 6.50 Prepaid Write for Our Circulars on Sets and Tubes

DEALERS : We have several Eastern dealers who are making good money on the Moorhead Tube, are you one of them? PACIFIC LABORATORIES SALES DEPARTMENT 534 PACIFIC BUILDING SAN FRANCISCO, CAL.

"LeaimbyDOin

METE N. Y. ELECTRICAL SCHOOL is the pioneer and premier school of the "Learn by Doing' method. When you have completed this Course you shall be fully qualified to handle ALL branches of Electrical industry. The equipment of this School is unequalled and up-to- the-minute. needed becomes' er' in this school. You can start lean n any day of any week throughout the whole year. Send for catalogue. NEW YORK ELECTRICAL SCHOOL 29 West 17th Street - New York City

You benefit by mention g "The Electrical Experimenter' when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 6oi

EYES AND EARS OF THE DEEP is driven by clockwork so arranged as to SEA FIGHTERS. be kept wound up to the same tension by (Continued from page 55o) lever B, acting on the spring every time it possible ?" you ask. Merely a possible ad- is depressed. aption of common electrical devices al- The rheostat C regulates the strength of ready in use, to the special requirements the transmitted signal ; F controls the di- of sub -sea navigation in mined and net-in- rection of the deck eye, the position of the fested waters. latter being indicated by the dial M, thus The apparatus might comprise a device the direction of the obstruction can be for locating large metallic masses, such as readily determined. If desired, the 'phones battleships, a sudden rise in the bottom can be switched into the checking magnet of the ocean or a sub -sea peak and to circuit to assist in determining the dis- indicate when they are nearing shore. Sec- tance to the object on scale A, thus giving ond, an apparatus for determining when a double check, both by noting the momen- the submersible happened to approach small tary checking of the pointer's movement masses of metals. and the sound in the 'phones. Let us consider them in the above or- The location of large objects being thus der. Referring to Figure we have the easily obtained it is a simple" matter to bow of a submarine. Mounted on the avoid them, but in the case of nets and deck or under the water -line as desired. mines the reflection of sound waves is not there is a huge siren or horn 2 or A', and great enough to show their presence. two microphones, 3 or B'; only one micro- We therefore take recourse to the oft - phone being shown in either case, the oth- described and remarkably sensitive Hughes er being on the opposite side. When placed induction balance. Referring to sketch, we on deck it may be swiveled and turned by see the differentially wound coils, 5, fit- "What Doin' means of the motor, 4. ting into a chamber. These coils are y' It is well known that sound waves will mounted on a rod 6, which connects with be more or less reflected by any large body a disc that fits tightly into the cylinder 7. they strike; this phenomena is illustrated By allowing comprest air to enter behind Now, Bill ?" by the well -known echo. Also let us re- the piston the rod is forced out and the member that sound travels at a certain coils are advanced some 30 feet in front You don't have to ask that definite speed through water.* Now, it is of the craft proper; admitting comprest question of a trained man, be- evident that if we send out a sound wave. air in front of the piston, drives it back which is reflected and then measure the to the normal position. cause you know his position is time and multiply by the velocity of sound These coils are connected to a similar a permanent one -that he is we shall have the distal-ice to the reflecting pair located behind the main observation not at the mercy of conditions object. switchboard. The latter are wound in the Refer again to the figure. At A is seen a same direction as in the usual balance as that affect the untrained man. large dial with a pointer that travels over described in a previous issue of THE ELEC- a scale graduated in feet. At B is shown TRICAL EXPERIMENTER. The coupling be- You can always be sure of a a projecting handle By pulling down, then tween the coils can be varied by means of good position and a good salary if releasing B, it flies up. On the return it the sliding handle E. Lever D controls you have the special training that operates the siren 2 for a moment, and at the comprest air actuating the piston of puts and keeps you in demand. the same instant releases the needle on dial the rod carrying the coils, 5; switch H al- A. As soon as the siren stops the micro- lows the 'phones to be connected into the The International Correspondence phones are switched automatically into the circuit with one pair of coils, switch G Schools will bring special training circuit by the action of B. throwing current into the other set, the to you, no matter where you live, As soon as A is released, it starts to strength of which is varied by rheostat N. at a certain rate of or how little spare time or spare move over the scale The principle is self- evident. While in speed. When the sound wave reaches the cash you have.. return, the current in a mine field the coils S are extended and a microphones on their balance lever E. When ap- them is varied, actuating the Audion am- obtained with To learn how the I. C. S. can and stops proaching a mine or net, which are large plifier, which energizes a magnet magnetic balance help you, and how you can easily needle on A for a moment. It will be metal bodies, the precise the is disturbed and a sound will be heard in, qualify for success in your chosen evident that with the scale of A, properly to read the the 'phones. Operating D draws the coils occupation, mark and mail the at- calibrated in feet, it is possible back into the chamber, placing the rudder distance to the object directly from it, tached coupon TODAY. Doing scale it trav- hard over and full speed reverse prevents postage. You since the distance around the an actual collision. so costs you only the els is dependent directly on the length of assume no obligation. If you think The switchboard is placed conveniently time consumed between the emission of the you're ambitious, marking the cou- signal and its momentary halt upon the re- near the wheel L, speed controller K, peri- ception of the reflected sound signal by scopes I and J and the bank of indicating pon will prove it. Do it NOW. devices necessary for the operation and the microphones. The needle is stopped Box 532 6 Scranton. Pa. by the magnet controlled by the Audion control of a modern submarine such as here long enough to obtain a reading before it considered. - - --- TEAR OUT HERE continues on to the zero mark. The needle A commander equipped with this appa- rINTERNATIONAL CORRESPONDENCE SCHOOLS ratus is, in accordance with my plans, Box 5326 SCRANTON, PA. Explain, without obligiting me, how I can qualify for *The velocity of sound through water is ap- therefore in a position to maneuver quite the position, or in the subject, before which I mark X. 4,000 feet per second. Hence, if the proximately safely among the enemy mines and nets. ELECTRICAL ENGINEER SALESMANSHIP distance be 100 feet to a reflecting object, the time Electrre Lighting ADVERTISING MAN taken by the sound in traveling from the ship to The objection might be raised that the Electric Car Running Window Trimmer the object, and from object to ship will be approxi- siren would warn the enemy of the pres- Electric Wiring Show Card Writer mately one -twentieth of a second. This effect has Telegraph Expert RAILROADER measure- ence of the craft, or in case the method MECHANICAL ENGINEER ILLUSTRATOR been utilized in taking "soundings" or Mechanical Draftsman DESIGNER ments of the depth of the sea in a very accurate of detecting submarines previously de- Machine Shop Practice BOOKKEEPER manner as cited by Mr. R. F. Blake (Prof. R. A. scribed in this journal was in use, the sub- Gas Engineer Stenographer and Typist Fessenden's work) in a paper presented before the CIVIL ENGINEER Cert Pub. Accountant of Electrical Engineers, at marine could easily be located by the ene- Surveying and Mapping Railway Accountant American Institute MINE NOREM'N OR ENO'R Commercial Law Philadelphia, Pa., October 12, 1914. The distance my. In answer to the first objection, con- Metallurgist or Prorpetor GOOD ENGLISH to hidden icebergs, even 2% miles away, was meas- sider that the mere knowledge of the pres- STATIONARY ENGINEER Teacher ured in this way, also, and the results were very Marine Engineer Common School Sabiesta It should be mentioned that a spe- ence of a submarine does not constitute ARCHITECT CIVIL SERVICE satisfactory. so, when it can move Contractor and Builder Railway Mail Clerk cial switching device or commutator must be used capture, especially Arehitentaral Draftsmen AGRICULTURE in such sound reflection measurements, which oper- safely through a netted district without be- Concrete Builder Textile Overseer or East ates so as to enegize first the sound producer, and ing caught in it. Structural Engineer Navigator Spanish the circuit to the microphone or re- PLUMBING AND HEATING Poultry Raising German then to close Sheet Metal Worker AUTOMOBILES Frenek ceiving resonators in time to intercept the "echo." Secondly, the microphones on shore are CHEMLIAL ENGINEER Ante Repairing U ItaW, For an interesting account of the present type tuned to pick up the high note of the mo- sound wave submarine signaling apparatus, carried Name by all first -class ocean -going steamships and war - tors and in case they succeed in locating it vessels the reader is refered to THE ELECTRICAL there still remains the difficult undertaking Occupation EXPERIMENTER for February, 1916. From these of capture. & Employer reports we find also that the deeper the submerf- Street ence the better the results, for the surface water Is That such a device would be valuable is and No not Suite as good a conductor of sound. Also the not so very doubtful the author believes; velocity of sound will vary slightly with change in at least it would seem to require a practi- City State temperature and corresponding variations in den- If namr of Course you -want is not in tide list, write it here. sity. cal test to prove it a failure. You benefit by mentioning "The Electrical Experimente?' when writing to advertisers. 610 THE ELECTRICAL EXPERIMENTER December, 1916

THE ARLINGTON RADIO 6,000 meters, and the other when the key STATION. is released, which would be about 5,900 (Continued from page 577) meters. kilowatt, 500 cycle SIXINONE inductor type generator. From the negative electrode a lead is loo Kilowatt Arc Set: The third set in- taken thru the hot wire ammeter, and then FUSE PLUG stalled at Arlington is a 100 kilowatt, arc to ground. The operation consists in first set, and shown in Fig. 6. This set consists striking the arc at reduced voltage, and by A wonderful invention of a suitable motor-generator, arc cham- means of finely that will save you in- a threaded screw arrange-. ment, bringing the carbon back, thus convenience and elec- lengthening trician's bills. Millions the arc, at the same time in- successfully tested creasing the voltage by cutting out resistance. This operation is repeated until full every year. No more voltage " blow- outs ". is on, when the length of the arc is regulated by watching the radiation hot No More "Lights Out" wire meter, there being a maximum set- A pull and a twist and up goes ting, from which the light again. Approved by opening or closing the arc National Board of Fire Under- causes a drop in the antenna current. writers. For homes, hotels, Illustrations courtesy Proceedings Institute- factories. etc. At elec- of Radio trical stores and Central Engineers. Stations. Write us, if not obtainable. 35c per plug of six fuses. THE DELINEATION OF INTERNAL ORGANS BY A NEW ELECTRICAL ATLAS SELLING AGENCY, Inc. METHOD. 450 Fourth Ave., N.Y. (Continued from page 553) as seen by the bystander, is very unimpres- sive. There is no darkening of rooms, no flashing of lights, and no crackling of Fig. 4. Connection s of 100 K. W. Spark Set at spark-saps. In Arlington Radio Station. fact, the whole proceeding is so brief, and seemingly so simple, that ber, magnet poles, magnet coils, induct- when the results are observed the first sen- ances and necessary switch panels. sation is one of bewilderment. The motor -generator embodies a 160 A patient is laid on a plain deal (wood) horsepower, 3 phase, 25 cycle induction table (insulated by standing it on glass), motor, and a generator rated at 500 volts a little clicking is heard in a cupboard hard direct current and 100 kilowatts; both by, and after sixty seconds or so the bear- mounted on a common base and direct -con- ers are directed to remove him. Nothing nected. The motor shaft has an extension, has been felt by the patient, little or noth- whereby a pulley can be mounted and the ing has been seen by the bystanders beyond set run by an engine or other prtme mover what has been noted, yet a visible record by means of belting. The control for the of the outline of a living organ has been motor is mounted on a switch panel and conveyed to a wax sheet. This is then X -RAY FLUOROSCOPES is controlled from a position near the arc printed on ordinary photographic sensitized 5x7 size with Astrale screen @8 by means paper by the employment of methods complete . . rPP 5U of a small switch, which oper- al- as shown O ready familiar in several "ASTRALE" X -RAY ates the contactors of the panel, starting other connections. SCREENS the machine on low voltage Have the fluorescent salts deposited directly on and automatic- The Appliances Used. heavy celluloid making the screen dust and water ally bringing it up to full voltage as the proof as well as mechanically strong. If there is nothing impressive about the Do not use old style paper screens easily punc- starting current is reduced. This machine procedure itself, is tured and which deteriorate in there also nothing es- time. is brought up to speed in four seconds from pecially remarkable in the appliances em- Sample order will convince you. the time the switch is closed. The wiring Standard ployed. For the most part they are of quite Sizes Complete Screens in Frame plan is shown in Fig. 7. 20 $1.50 5z7 $5.00 8x10 $10.00 a familiar kind. Some are kept in the cup-. From the copper or positive electrode, a ROSENTHAL LABORATORIES, CAMDEN, N. J. board mentioned, while the rest -namely, heavy lead is take.[ to the helix, and thence the electrodes and connected wires -are to the antenna. In series with the helix, suspended in the room. DEPENDABLE J'!4 is a smaller helix of twelve turns, giving The main contents of the cupboard are KNAPPFIVE-SPEED a wave length change of about two hun- seen to be two separate electrical batter- REVERS BLE dred meters; and from each turn of this ies (Battery A and Battery B) of pre- helix a lead is taken to a twelve point re- ELECTRIC SPECIALTIES cisely equal strength, together with a means MOTOR lay, which is operated by 110 volt direct by which A powerful, specially geared, durable motor alternations in their currents can for boys and experimenters. Affords five $ current. The resulting action when the be produced and varied at will. The other power changes, varying from very rapid to contacts are closed (which happens when very slow, with increasing power In each step. contents 'include a revolving cylinder over Especially adapted for driving mechanical toys and the hand key is released), is that the wave which is devices of every kind. suspended a needle hammer capable is shortened by the twelve turns of induct- of side to side as well as up ance being and down short -circuited. When the hand movement, the two together bearing a re- semblance to a barograph. This cylinder carries a rolled sheet of paper treated with paraffin wax on which the outline of the organ under examination is initially recorded. The needle hammer mentioned is connected with a tiny circle of carbon like the diaphragm of a telephone machine, which is operated in its turn by a current detector capable not only of picking up and AT ALL LIVE DEALERS measuring, but also of concentrating cur- Insist on your dealer showing you the KNAPP line rents too small to be convertible into force KNAPP goods are best. If your dealer cannot supply- you, order direct. Send for FREE illustrated cata- by any other means. The current in this logue showing a complete line of Electrical Motors particular case and Novelties ranging in price from 10e to 810. comes from the patient's body, arriving through a wire connected KNAPP ELECTRIC & NOVELTY CO. with one of the two electrodes. 523 West 51st Street, N. Y. City There are two of these electrodes each of which ends in a perforated zinc plate or zinc wire screen, which is not placed in Generators! Alternators! conta,.t with the patient's body. One of these, hereinafter We have a complete line of sturdy, efficient gen- Fig. 7. How the 100 K. W. Poulsen Type Arc called Screen A, is about erators and alternators from 100 to 1000 watts. Transmitter at Arlington Is Connected. 18 inches broad by 12 deep, and stands We furnish complete parts for these finished ready to assemble with instructions to wind. Trans- vertically on a pedestal, which, being mov- formers made to order. Send for catalogue. key is pressed, as in operating, the contacts able, can be put in the same plane as the ALL AT FACTORY PRICES are opened, thus lengthening the wave. patient's body and in its immediate vicinity. Bergmann Motor Works, 442-446 Niagara St., Buffalo, N.Y. Thus there are two distinct waves sent The other electrode, Screen B, is about out, one when the key is pressed, of say (Continued on page 678) You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 611

DR. LEE DE FOREST THIS as weal as a soft answer does; and, after MONTH'S SUPPLEMENT. we had lain low for a few days, the neigh- (Continued from page 561) bors forgot our outfit, or found 'something line Master Electricity and in a commercial form. This first Aud- else which peeved them more. So the ion differed in that it was not a rectifier stayed up ánd was opened for operation. The business-end of our enterprise was From Records of but a genuine relay, a local current passing the "Con- all the time through the telephone receiv- an organization modestly called ers, this current being decreased upon re- tinental Telegraph Company." It was fully Actual Practice exact officered, with president, vice -president, sec- ceipt of signals- apparently the op- retary, treasurer, general manager, chief posite of the method employed in the Flem- minor positions. As ing valve. But before the two electrode inspector, and several Dr. there were only four of us in all, this ar- Audion could be generally introduced rangement gave us several offices apiece, de Forest invented the grid electrode, ap- which prevented any one's feeling slighted plying the high frequency oscillations to and gave each a chance to "boss" some- instead of W TICAL ACT(CAL a third intermediate electrode body. None of us would take any orders 1,iICTICAI the plate as in the preceding type. to from another one, but a fellow as vice - JiCTRICITY Every radio engineer knows the enormous president, for instance, could bully himself uTRIC)TY flETR[CITY advantages which the grid electrode intro- as chief inspector all over the lot; and duced. made possible the Ultraudion and }CL(FFE It on the other hand, if he went too far, he 4{'L1FFE tdía,¡fFE the oscillating Audion as a source of pow- could turn right round and tell the vice - er for transmitting purposes. president what he thought of him and dare In 1911 and 1912 Dr. de Forest was Chief him to fire him. wit ME I Research Engineer for the Federal Tele- The line did nothing but regular business 'itOME 11 l'plkm graph Company, in San Francisco, Cal. In at first, but, after a while, that grew stale. 1912 rights to the Audion amplifier as a Then it was found that, by one means and telephone repeater were purchased by the another, the sounders in all four houses SHIPPED TO American Telegraph and Telephone Corn - could be made to give forth a variety of YOU pany. The Audion repeater is to-day used novel noises and business was diverted in in every long distance telephone line ex- that direction. With a contact -spring rest- tant. It alone made possible transconti- ing on a ratchet-wheel, you could produce nental telephony. The Western Electric a rattle, buzz or squeak, according to speed FREE FOR Company manufactures these by the thou -, -especially effective in the dead of night, TEN DAYS' sands now for telephone purposes. when it woke not only your fellow -mem- Dr. de Forest in 1913, first demonstrated bers, but their entire families, causing EXAMINATION the oscillating Audion as a source of radio fathers to bellow up attic -stairs words sig- frequency current. The development of nifying that the monkey- business must the Oscillion as a source of radio power cease. A loose- contact, formed of two has gone on from that day very rapidly. hanging weights lightly touching, was also To-day it is possible to obtain a K. W. admired-by its originator, nobody else. or 500 watts of high frequency energy from As his mother walked about the house, a bulb but 6 inches in diameter and by this brewing doughnuts or making beds, the The real facts about electricity are what you want t o get at. means to telephone wirelessly 300 miles. weights would jiggle together and send In your electrical books you want accuracy With 500 -twenty watt Oscillions connected spasmodic stutterings down the line. From and practical application. If you would ad- in Arlington recently the hu- we into vance rapidly you must have records of actual parallel at such crude beginnings, progressed practice. man voice was heard as far as Hono- clockworks carrying commutators which You haven't the time nor inclination to go lulu, T.H. There is no question that the would send out a name, like "Alice" or nto useless theory and puzzle your brain over destined to surpass all forms "Mabel," hour, till the cussed higher mathematics. Oscillion is hour after Your wants and demands are now fulVmet of the spark transmitter, so that in years thing ran down -the name of some girl, in the Home Study Course in Practical Elec- to come the spark will be as obsolete as you understand, that a fellow was sup- tricity .. by W. H. Radcliffe. marvelous coherer of Mar- be in" but really wasn't Few men are fitted to write books on the im- the one -time posed to "interested portant subject of electricity. Few men possess coni. at all, no sir, never so much as noticed both the ability.to perform the work and tell Dr. de Forest has taken out 85 United. the darn fool. the other fellow in writing how it is done. deviltry The fact that the author of this Library has States patents on radio inventions and a I'm free to confess that this run the scale of electrical practice, from the large number of foreign patents. wasn't confined to any one member. We ground up to the position of expert for the One of his latest inventions is the use all tried to be as annoying as we could, largest electrical company in America, has annoyers, as fond made these books the accepted standard of of the Audion for the production of musi- and we were some little today. cal frequency currents for producing sus- teachers and a few selected neighbors could It la difficult to tell just how valuable they tained notes and for remarkable range of testify. But one imp of depravity named are, and how rapidly they will advance both rest of us. Man the trained and untrained man, unless they are quality. It is predicted that an instrument Dan had it all over the put to the test. surpassing the organ in beauty and flexi- alive, he would have had patient old Job be day produced himself chasing him red -eyed. Dan isn't PUT THE BOOKS TO THE TEST AT bility will some on this OUR EXPENSE his right name ; it would be mean to tell principle. Glance at the sub;ecta mentioned below, then fill it, because he has reformed and is real out the coupon and return to us. Act now. Take UPS AND DOWNS OF A gentle now -at least, everybody thinks so our word for it, you won't regret doing so. says he's worse A Few of the Important Subjects Covered: -VOL. I TELEGRAPH LINE. but his wife, and she than -Lead ng Principles. Electrical Units. Conductors (Continued from page 566) he used to be. and Insulators. Calculation of Resistance. Electri- tele- cal Circuits. Primary Battery Cells. Storage Bat- idea that it was just an ordinary, After every new breach of the tery Cells. Magnetism. Electromagnetic Induction. had the graphic peace, we'd hold a meeting and Direct- Current Generators. Alternating Currents. nice, shiny wire, and we didn't disturb the Alternating- Current Generators. VOL. II-Trans- knew it was wrong, pass a stiff by -law prohibiting that particu- formers. Electric Measurements and Instruments. idea in the least. We monkey- shine; and as a result of this Switchboards. Swit 3hboard Wiring and Operation. too, because we didn't have a poet's li- lar Station Wiring. VOL. II I- Direct -Current Motors. Dan's inventiveness, our book of by -laws Alternating- Current Motors. Motor-Generators, cense; but it was so hard to get the per- Statutes Dynair otors and Rotary Converters. Incandescent we stretched a point. At bid fair to rival in size the General Lamps. Are Lamps. Substations. Management missions that is as of Electrical Stations. that time the telephone and electric -light of Massachusetts, which a volume companies were saving money by using thick as it is wide, and it's no narrow tome, believe me. At last, the bright idea struck as far as possible ; and a - - -- Free Examination - - -- house -supports single law, on the lines sometimes col- us to compose a McGRAWHILL BOOK COMPANY, Inc., house in a popular location Act, which lected wires till it looked like a gigantic of the Sherman Anti -Trust 233 W. 39th St., NEW YORK should be so broad that it would cover the Gentle men:-Send to me, charges paid, the Home Study harp that had been through some sort of Course in Practical Electricity, e volumes, price 56. use of any kind of "infernal- machine." the an accident; so people were getting shy teen day,. and the atthe rate of $ per mouth. If We did our best with that law. Dan, book. are not wanted I will write you for ehippmg direction. of that wire- thing. as strung our wire all in one after- the chief offender, was just as interested We the rest of us, and helped to make it good Shiflett re noon, and went to the Kickapoo Indian it didn't show in the evening; that was so as to be and tight. When it was done, Your Address the neigh- appear to leak' a drop and we believed no- .out of the way in case any of any kind City and State bors called with criticisms. Several of body in the world could think up They said our wire reminded of hand or clockwork trouble -mixer that Name of tmployer them did. it wouldn't land on in a minute. them of the dump, or words to that effect, His Address and we must remove it immediately-per - And that masterpiece of a law was no haps the next morning at sunrise would do. sooner copied into the book than Dan gave Your Position r E Dee. But a little delay turns away wrath almost out that he had invented a way to beat it! You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 612 THE ELECTRICAL EXPERIMENTER December, 1916

*********.x.**************************************.***** Whether he had or not was a perfecta even bet, because he was as good a bluf- I.)OyS i Here ils Your Laboratory fer as he was an annoyer. We pooh - poohed his threat, of course, and dared * CHEMCRAFT * him to produce his invention. He only * % A Complete Outfit of shook his head and invited us to wait and T G 00 CHEMICALS - (39 Chemical Reagents) APPARATUS - (All Necessary Apparatus) see. Days went by, and deep peace brood- - (The 38 page Chemcrah Book) ed. was * E IC CO' INSTRUCTIONS It almost too deep. The pep * Ç 00oC yr Ö"Ö for performing over 50 Different Exper ments. seemed to have vanished from the tele- * \ail ' tDW" B .' Each experiment can be repeated many times. graphic world. Honest, we almost * reset. Under the heading "Chemistry and ItsAppli- wisht ntRS* ". cation to the Industries" are many experiments we hadn't past that law. * m£ s ' in which the products of our great chemical in- Now, Bugs, the climax of this story is eoaK . w dustriesare really manufactured on asmall scale, coming and I don't know whether to put .1( ® Everything is explained in a clear interestingway. * also contains 30 mysteriousexperi- the cart before or behind the horse in sc . mentsChemcraft in telling it. Chemical Magic. Its great fun to * It's interesting either way, as * ?' T 1` .- 4 show these to your friends aF the fellow said about the elephant, when \a1a) With this outfit all experiments now appearing in * he couldn't decide which it _ s. i ExperimentalChemistry "inthe "ElectricalExpen- * was the head -end. menter" can be performed. * On the whole, I'll vote for the cart -first, so If your dealer does not have Chemcraft we will I'll let you into Dan's sleeve and show you 9( - -- - _, _-1 -- = send yours direct. Price $2.00 postpaid Send he it - today for descriptive literature. what had up it. Dan's house had lightning -rods on * Dealers write at once THE PORTER CHEMICAL CO., it- Hagerstown, Md. the ancient, twisted things once so familiar, which wobbled and sagged till their joints opened up good and wide. Hospitable old Give rods ! they wouldn't hustle a lightning -bolt right through to the ground without even a Flex/We Flyer saying "Howdy -do." No, they made it The sled with the famous welcome; they said "Stop a while ; come on The non -skid runners in the house and amuse yourself with always welcome gift for youth of all ages. A real "snow- mobile" which means the healthful fun and companionship. New construction nickel Includes grooved runners of chrome kitchen -stove and the baby and grandpa's steel which prevent skidding and Increases speed and control. All-steel durability, flexibility and accuracy of steering. front adds false teeth till it stops raining. shoes. Prevents No more dragging of wet feet and wearing out colds and saves doctor's bills. So strong and scientifically made it Well, as far as Dan went, all his idea Outlasts 3 ordinary sleds was to take a piece of wire and connect I isn't Flexible a Flexible Flyer Flyers are sold by hardware and department stores, nine sizes, 3 to Sts ft. the top section of one of those rods to our unless it bears this / Trademark. carries two children, 4 ft., lgtz lbs., price line, figuring that, during the next thun- T Junior Racer $3.50. I 16 derstorm, some new kind of a tickle, and S. L. Allen & Co. Box 906K Philadelphia /rte maybe a spark or two, would go through booklet and cardboard model show- -and he wouldn't be the one who was do- Free Olier Attractivehow ing Flexible Flyers steer. Send Postal. ing it, would he? So the law wouldn't apply. He was just going to make nature work for him. When you take nature into partnership, however, you want to be sure that you're Wireless Taiiht By Mail the head of the firm. Dan wasn't. Na- : ture is some trickster herself and, further You May Learn Theory, Code and Laws of Radi. down the line, she had a contraption of her Comm own that she thought would work in fine uniation In Our School or a t Your Hom with Dan's. At that point an insulated ^ \ fitting you for positions paying good salaries with wonderful ¡l electric -light wire had been strung over chance to travel the world over. It's the most interesting pro- C ours. Nature went to work on that light- fession known and the demand for skilled operators is increasing. wire, and by heat and cold and gravity - Send stamp for catalog giving facts. Resident classes El pull and wind -waving, stretched it till it open Oct. 2nd. 'lay on our poor old rusty, innocent line. NATIONAL RADIO SCHOOL, 14th& U Sta., N. W., Washington, D.C. Then she worked at it with friction till all I J a was gone the-insulation except a thread or Offers svantages 'WASHINGTON These Coura two, and her little joke was all ready to us;, /. spring. Just a spark from Dan's lightning - ` . lt:L fie i rod to start an arc, and the full- fledged dynamo- current was prepared to saunter A USEFUL MODERATE PRICE GIFT into our happy homes and perchance start something. It was a sultry night in August. The `; $1a 00 Pen ci ¡iccrni' /ok /s heat was the kind that makes you peevish Non- leakable suits any hand. Guaranteed, last alife- with the sheet because it's so much hotter tune. For all writing. Para rubber, precious metal o be carried point e., andblack, long than you are, you don't know why -and andrir short. [Special! mcink s black, glyf le] Mail or- - ders with R. supply CO., Agents probably the sheet is just as peeved with wanted. J. R. L'LLRICN ACO.,E7 ThsmesThames Bb, N.Y. you for the same reason. A thunderstorm was grumbling gently, way off on the horizon. The Continental Telegraph Cómpany, on its four separate beds, tost in a LEARN WIRELESS troubled half -sleep. (That's going great; At the largest, best equipped and ONLY practical Radio School in New England. like ENDORSED BY GOVERNMENT AND MARCONI OFFICIALS. Last year we sounds just a chapter from "Myrtle placed EVERY graduate in good positions in all parts of the world, and still we are Clayton, or Wrong from the Start. ") unable to fill the demand. Complete course in 6 months. Day and evening classes now forming. Easy payments if desired. The storm crept nearer and nearer, black- Send stamp for new fall prospectus er and blacker ; but silently now, for it had 899 B BOYLSTON BOSTON, something to do. The air cooled by de- STREET EASTERN RADIO INSTITUTE MASS. grees and, as it cooled, the sleep of the Continental Telegraph Company became more peaceful and profound. Suddenly, I woke with a start. The Rocky Mountain Views lightning, having crept near enough, had In nature colors. 17 DeLuxe 5x6 Pictures, in Art folder. pounced. An interval, and then another Sent Postpaid with one year's subscription. flash, nearer yet. The window was filled Three folders (all different with three years) . Seven with dazzling light. There was a spark folders with 5 years (can be sent to different addresses). from the lightning-arrester on the instru- One Subscription one year .25 ment -shelf and the sounder gave an un- EARN $2,000 TO $10,000 A YEAR Three years .50 easy kick before the crash of the thun- We will teach you to be a high grade ealeeman In eight weeke at home and assure you definite proposition from a large num- Five years $1.00 der came. Der of reliable firma who offer our studente opportunities to earn Bie Payy while they are leaning. No former experience me speed regnires Wrteati don for partienlare,batet hundreds of good THE ROCKY MOUNTAIN MAGAZINE Lightning had nothing on for openings and toetimontals from hundreds of our tudente now in out of bed and into the hall. I earning $100 to 51,00 a month. Address nearest office. Dept. esl Quincy Bldg. Denver, Colorado getting NATIONAL SALESMEN'S TRAINING ASSN. peeked around the door -frame for further Chicago Now York San Frandsen (Continued on page 615) You benefit by mentioning The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 613

R. S. & A. B. LACEY Established 1869 Members Bar linked States Supreme Court and Supreme Court District of Columbia. r C. PATENT PRACTICE EXCLUSIVELY

Edited by H. GERNSBACK In this Department we publish such matter as is of interest to inventors and particularly to those who are in doubt as to certain Patent Phases. Regular inquiries addrest to "Patent Advice" cannot be answered by mail free of charge. Such inquiries are published here for the benefit of all readers. If the idea is thought to be of importance, we make it a rule not to divulge details, in order to protect the inventor as far as it is possible to do so. Should advice be desired by mail a nominal charge of $1.00 is made for each No motter how much money you O UG H T to get for Only one side of your invention, it is not likely to bring you a penny question. Sketches and descriptions must be clear and explicit. unless ycu know who: you are about in selecting at- sheet should be written on. torneys. WELL-KNOWN patents worth millionsof dollars, secured through us, made our reputation as AMPLIFIER. PATENTED ARTICLE. "The Attorneys Who Obtain (109.) C. W. Halligan, Pennsylvania, (1í4.) Charles Welsh, Philadelphia, Pa., Patents that Protect" of a radio amplifier to would like to know the following: If a Abundant evidence. such as you can readily sends us a drawing the unsurpassed be used in telemechanics. He wishes our person has a patent on a certain article, verify, will be submitted to show can another person make that article for success of our clients, and that advice if the device is practicable and if a The Patents We Obtain Are Not the Kind patent could be obtained. his own use? Merely Said to be "Wanted," but the Kind (A) The device in question would not According to the law, a private person that Manufacturers BUY cannot make and use, even for himself, No lower charges than ours are quoted by any other work satisfactorily for the simple reason trustworthy attorneys; and we do not, by deceptive that a polarized relay is used in connection an article that has already been patented. free offer, money -bank schemes, or in any other way, use our terms as a bid or bait for patronage. Mere rep- with it and we have not found a polarized If the patentee finds out that another per- resentations, boasts, and promises, characterize much relay as yet that can take the fastest "send" son is making and using an article on fine patent literature i.nd advertising. but we challenge which he has a patent, he can stop him a comparison of RESULTS. of an expert operator. Also, a device of Reliable book containing information not obtainable this kind would obviously be of no use for from using it. As a rule, however, it is in any ocher pubücat:on and worth a possible fortune to YOU if You have iaventions to be patented, will be radio telephony, and for this reason we very difficult for a patentee to do this as mainedree on reques. Write. cases, does can give but little encouragement to our in the majority of the patentee R. S. & h. B. LACEY, 99 Barrister Bldg., Washington, D,G correspondent. not know who is using his patent for private use. STREET CAR INDICATOR. DRUM Ind., has PROTECTOR. (110.) W. Bethel, Indianapolis, Frankovich, invented an automatic device for street (115.) Michael Anaconda, cars to show the street approaching, and Mont., has devised a novel ear protector he claims that it can be easily reset in case for protecting the ear drums from sound PATENTS created by firing big guns. Our ad- car is obliged to take a course other than waves regular one. It can be installed with vice is sought on this invention. IF YOU HAVE AN INVENTION the This is a very good idea and if carefully little expense and can be regulated to show which you wish to patent you can The worked out, a good commercial article streets when leaving the last stop. write fully and freely to Munn & Co. device is not worked from the track and should be produced from this inven- is supposed to be weather -proof. tion, provided it can be sold cheap enough. for advice in regard to the best way (A) We refer our correspondent to An English company at the present of obtaining protection. Please send query No. 107, in which we stated our opin- time makes an ear drum protector, but sketches or a model of your inven- ion clearly. it is the only one on the market as far as we are aware of. We think the idea tion, and a description of the device, ELECTRIC COMBINATION. of our correspondent is thoroly prac- explaining its operation. (112.) Emil Moir, Hoboken, N.J., has tical and believe that a patent might be All communications are strictly confiden- submitted a very ingenious arrangement of obtained on it. Our correspondent also tial. Our vast practice, extending over a submits sketch of an auxiliary heater to period of seventy years, enables us in many an electrical combination, the idea being to cases to advise in regard to patentability complete an electric circuit from the dif- be used on a kitchen stove, and he desires without any expense to the client. Our Hand - ferent parts at different places. Two to know our advice on it. Book on Patents is sent free on request. This Frankly, we do not think much of it, as explains our methods, terms, etc., in regard sliders are used to vary the combination to Patents, Trade Marke, Foreign Patents, and several other novel means are described it is very difficult to get more heat from etc. a stove, simply by putting an attachment to make the device rather effective.' All patent. eecurec through ue are described without (A) A device of this kind certainly can to it. Of course, in the present case, the cost to the patentee in the Scienl fc American. be patented. There might be a fair market radiating surface is increased, but we do developed as there seems to be a demand not think that an expensive device of 'this for an article of this kind. We would ad- kind would be practical from a commer- vise our correspondent to get in touch with cial standpoint. MUNN & CO. a patent attorney. ROTARY TUNING COIL. SOLICITORS OF PATENTS (116.) Frank Harrell, Jr., Tampa, Fla., AUTOMOBILE SIGNAL. 699 WOOLWORTH BLDG., NEW YORK (113.) G. D. Ryder, Danbury, Conn., has has invented a rotary tuning coil and wishes an idea involving the use of a loud -talk- to know if there is one already on the ana 625 F STIL EET, WASHINGTON, D. C. ing telephone transmitter in front of an market. He wishes to know if it could automobile, and by use of amplifying be patented. means to step up the voice in the horn could be heard for some distance. which Write for List of Patent Buyers who He claims that anyone using this device PATENTS WANTED desire to purchase patents and What can give warning to people in front and in To Invent with valuable list of Inventions Wanted. $1,000,000 in prizes offered for in- back of the automobile; he wishes to know ventions. Send model or sketch for Free Opinion as to patentability. We have a if the idea is practical and if a patent Special Department devoted to Electrical Inventions and ar.. in a position to assist could be obtained on it. and advise inventors in this field in the development of their inventions. The idea certainly sounds novel, but we doubt very much if it would come into MODERATE FEES --WE ASSIST INVENTORS TO SELL THEIR PATENTS general use by automobile owners. For Write To -Day for our Five Books sent free to an address. (See attached coupon:) one thing, the cost is against it. Also, de- .Mi .as11a...NRREE COUPON rm. mo. Ma vices of this kind are not too reliable. . We do not think that a patent could be ob- I VICTOR J. EVANS & CO., Patent Attorneys i tained on a device of this kind for the I NEW YORK OFFICES: i89-19i Broadway PHILADELPHIA OFFICES: Ise Chestnut St. simple reason that merely using an article i Main Offices: 779 9th Street, N. W., WASHINGTON, D. C. ; that has been upon the market for some- I GENTLEMEN: Please send me FREE OF CHARGE your FIVE Books as per offer. time, on an automobile, does not make it LNAME ADDRESS 1 patentable. a_ at a. asat a. ass sat ..t! You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 614 THE ELECTRICAL EXPERIMENTER December, 1916

A coil almost identical to the one submitted by our correspondent was published 0 some years ago in Modern Electrics and EXPERIMENTERS!! later in THE ELECTRICAL EXPERIMENTER, a 0 WE SPECIALIZE IN similar coil was published. While an ar- 0 SEAMLESS CARDBOARD TUBING ticle of this kind will undoubtedly work, IN SIZES SUITABLE FOR ó it is too difficult to construct from a manu- O TUNING COILS, LOOSE COUPLERS, facturing TESLA COILS, Etc. ó viewpoint as the time lost in 0 winding is entirely too great. SPECIAL CRAY TUBES 0 A "STOP" FOR PHONOGRAPHS. PRICE LIST O Smooth Wound Wireless Tubes (117.) C. Moffet, Colo., wishes to know Outside Lgth. Price Par, GENERAL INFORMATION if an automatic stop for phonographs is O Dam. Post These prices include PARCEL worth anything. He furthermore 3 x 734 .12 .18 POST CHARGES: and are Choose a Tool for claims O shipped at once on receipt of to have invented a new needle 334 x 715 .12 .18 order and remittance. holder for We CANNOT furnish these V Your Present phonographs which increases the volume o 4 x 734 .15 .22 tubes In longer lengths than 735 unless ordered in quan- to the ''handy" man of your house or of sound and improves the tone. He 435 x 734 .20 .27 let it be known o titles of 100 of a size. that is your choice if wishes to know if he should patent the 5 x 734 .25 .31 We CAN furnish SPIRAL you are that man. idea. o WOUND TUBES in any Any Millers Falls 535 x 734 .25 .33 length up to 45 inches at .02 per tool will give years As to the inch in the following inside of usefulness and pleasure. first idea, there are several o 6 x 735 .30 .37 diameters, 334-4-4%-54. Here is automatic stops on the market now and not being thoroly familiar with our cor- o BEETLE & MACLEAN MFG. CO. 21 BROMFIELD respondent's device, we do not know if a 0 ST. BOSTON, MASS. MILLERS FALLS patent could be obtained on it and whether OOwO o 0 0 o o o o o o it is of sufficient interest to sell the idea BIT BRACE in case a patent were obtained on it. Na.732 As to the needle one of the most popular tools made holder-without actu- that gives the maximum of service at ally seeing what the article is, we cannot a moderate cost. tell if it could be patented or not. There PORCELAIN Covered ratchet gets into out -of -the are a great many such holders "THAT'S OUR BUSINESS" way places- ball -bearing on the mar- you head gives ket now and we would advise great boring power. Chuck takes our corres- Standard and Special Shapes, Regardless all square shanks and round shanks pondent to get in touch with a patent at- up to half inch. torney and have a search made as to the of How Difficult Coco bolo handles handsomely patentability of the idea. We illustrate one nickel plated makes a- tool hard shape we make. ing appearance. of strik- A pair of rolls 75.Ç' long and 14" in A PECULIAR diameter with 8 holes on ends and middle. Send for catalog and we will in- THUNDERCLAP. They must be perfectly straight and we clude Handbook of Mechanical A writer in Nature, living at Aberdeen, make them so. It's hard but not for us. information free on request. We can make your difficult! designs also. Scotland, describes a peculiar thunderclap Send us blue print for quotations. MILLERS FALLS CO. which occurred during a severe thundet- "Toolmaker to the Master Mechanic" storm on July twenty- seventh. This parish Union Electrical Porcelain Works MILLERS FALLS, MASS. lies in a hollow of the hills, and almost al- N. Y. Office: 28 Warren St. ways escapes close contact with. thunder- TRENTON, N. J. clouds. On the date mentioned a peal of extraordinary suddenness, resembling the crashing burst of a big gun followed in- stantaneously a vivid flash at my point of observation. AN INDISPENSABLE Two or three trees were afterwards observed to have been struck and "RED DEVIL" PLIER a fence rail near some wire was split into WANT'!PSannfacPreen pieces are writing for patent. procured For the Tool Kit or Work Bench and thrown some distance. Now the through me. FREE: 72 -page guide book, 5oeee,,ful Patents "; "Stepping Stones" (containing peculiarity is this : that very hnndrede similar experi- of invention. wanted, etc.); and 'Patent Promotion," (telle An 8 inch combination plier ences were noted at places how to sell your rights; chief causes of failure, etc.) Send for more than a mile them. Flee with adjustable jaws and distant and in various directions. The same manufacturing facilities. Advice free. screwdriver in handle. Made crash following immediately on the light- RICHARD B, OWEN, 164 Owen Bldg., Washington, D. C. for handling bolts, nuts, pipes, ning was noted by quite a number of inde- wires, screws, etc. Useful on pendent witnesses. A mile to the east of REGISTERED wireless sets, gasoline engines, my dwelling the lightning PATENT ATTORNEYS was seen to run PATENTS AND TRADE MARKS motor -boats, automobiles, etc. down a wire fixed to the top of a flagstaff. Nickel plated finish. Sample About a mile to the north a farmer driving mailed for SOc. Style No.925. home was alarmed to see the lightning flash Tool Booklet Free along the wire fencing by the roadside and split one post at least and cast the frag- 252 Ouray Bldg. Washington, D C. SMITH HEMENWAY CO., Inc. I ments on the road. Book " Inventions -Patenting and Promoting ' Free 107 Chambers St. New York City Improvements wanted -Send tor free bulletins On considering all the circumstances, I & advice think the following may be an explanation : The thunderclouds which contributed most- SOMETHING. It Experimental and Model ly to the storm were floating at a pretty Work high elevation, possibly two thousand feet, INVENT May Bring Wealth. ELECTRICAL INSTRUMENTS AND as during the greater part of the day, they Our Free Book tells What to Invent and How FINE MACHINERY were just grazing the tops of the hills. But to Obtain a Patent through OUR CREDIT SYSTEM. Inventions developed. Special Tools. Dies. about three p.m. a bank of cloud began to WATERS & CO., Succeeded by Gear Cutting, Etc. form in this hollow much nearer the ground HENRY ZUHR and half an hour later, when the thunder- TALBERT & PARKER, 32 -34 Frankfort Street New York City clap came, the light was much obscured. 4287 Warder Building, Washington, D. C. My opinion is that the lower cloud drew an overwhelming charge from the clouds above, and accordingly flashes sped to earth GROBET SWISS FILES from OSTON WIRELESS Are the standard of excellence to several points at the same instant. files, and have been for over 100 I have, of course, made certain that we Rotary Condenser, 43 plates, .001 M.F., $3.75 Tuner, 52.50. Spark Gaps. 60e. and $1.00 years. We send postpaid as an In- are dealing here with one and the same Detectors, troducer 48 files $1.00, 51.75, $4.00 especially adapted thunderclap, Loose Coupler, S7.50, 1500 M for too' makers and machinists on as was not difficult to do, see- receipt of $5.00. This Is a chance to get a set of ing that all the other peals of thunder were Agent for A. W. Bowman dr Co., Adams-Morgan Co. files you'll appreciate and we'll get future ordeal. comparatively distant. Manhattan Spark Coila. Catalogue for lo. stamp. MONTGOMERY & CO. M. MUELLER,18 Devonshire 100 Fulton Street New York City RADIO IN AFRICA. Street, BOSTON, MASS. UmakeM +Spare Time = Furniture,Toys and Money Widely separated settlements in the Con- go Free State have been linked and con- Learn Watchwork, Jewelrywork and $2.00 outfit establishes you in business nected with civilization by a system of A fine trade commanding a good sal- If your dealer doesn't carry UmakeM write us quick. Engraving ary, and your services are always in wireless telegraphy which covers 3,000 demand. Address HOROLOGICAL Department, Address: UmakeM, New York miles of African jungle. Bradley Institute, Peoria, Ill., for our latest catalog You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER

UPS AND DOWNS OF A graven images, gazing spell -bound into the TELEGRAPH LINE. the while every note of the wondrous mu- (Continued from page 612) sic seemed to search out some corner of developments. i lie peeking was excellent; our .inner being and finding there a re- so good, in fact, that it seemed wholly un- sponsive chord. The music had but half necessary to crowd the other things in that finished when I almost sprang from my room by the addition of my presence. chair in alarm, for there, above the flick- The storm was nearly overhead and each ering flames, slowly appeared the face of succeeding flash and report was heavier HIM who died that the world might be than the last. Things seemed to be hold- saved. What a wonderful spectacle -one ing together fairly well, however, when - never to be forgotten. That symbol of bing ! a tremendous ripping, tearing dis- goodness rested before our eyes as the charge took place ; and this time there be- chimes continued their glorious, heavenly gan to be doings on my instrument -shelf. music. We moved not when the last lin- Hot arcs played about with a sizzling noise. gering echoes had died away into a silence The sounder tapped wildly, buzzed, stuck, so intense that the faint cloud of smoke and slowly grew red -hot ! Smoke rose up. about our heads appeared as if hewn The batteries boiled and gave off ugly from some solid substance. Then slow- green fumes. It looked like a pocket -edi- ly the startling image above the flames tion of the end of the world. faded away into the translucent air. Now, if I wanted to, I could claim to Would someone but break the silence? have been cool in the face of disaster be- Not a word was spoken but I noticed that Big Money in cause what I did was quite effective. But Polar's hand trembled as he lit his cold I will not deceive you; I was rattled. I pipe and enshrouded himself in a cloud had just one thought -if the house burned of consoling smoke. Suddenly he sprang Electricity down, it would be my fault, and father to his feet and picking up coat and hat The Electrical industries offer would be displeased and might mention the donned them in silence. Turning to the fact. I left my wits in the hall, never ex- "Wiz" he extended his hand and that wonderful opportunities to boys with pecting to see them again. Rushing into shake meant more than ever could be con- a liking for Electricity. The salaries the room, I seized a baseball -bat that stood veyed by mere words. In his eyes as he paid to trained men are large, pro- in a corner and landed a three- bagger on left was the light you see in the eyes of Station B of the Continental Telegraph high strung race horses, in the eyes of a motion comes rapidly and, best of all, Company. For an instant the air was full red- blooded, joyful child, in the eyes of the wort is fascinating. of hot metal, burning wood, broken glass, all those who strive for high things and and battery -fluid; and then there was high ideals. In silence he left. The discovery and development peace. That is, if you could call it peace "Wonderful," I breathed to the "Wiz" of new lines (such as wireless teleg- where the smoke was rising from a mass as he returned to the fireside. of varied wreckage and wild cries were ex- "Yes, in effect but not in arrangement," raphy and telephony), from time to uding from the family, with their necks he confided and seizing the edge of the trine, promise attractive and paying craned over the attic stairs. fireplace he gave it a tug. It swung away fields tc those who wish to special- The next morning four fathers put four from the wall slightly and motioning me to ize. to do and Special feet down as one, and the Continental follow, he squeezed his way to the back of it. The will Telegraph Company went into liquidation And the secret was out. For the mu- Training will br ng success to you. without declaring a dividend. Four crest- sic he had arranged a supersensitive mi- fallen Bugs were seen -in fact, were in- crophone on his aerial mast which picked The International Correspond- tentionally overseen -while they toted a up the music from the steeple of a neigh- ence Schools can help you to be- ladder from house to house, pulling down boring church. come an expert in electrical work, erstwhile and rolling up into history their This microphone was connected to an no matter what branch you like String of Pearls. If I have been too long Audion, the effect of the combination be- in unrolling it again for you, I beg your ing to amplify the received sounds which, best. Thousands of young men have distinguished pardon. I thank you for your by means of a loud -talking telephone, were already won success through I. C. S. kind attention. made audible all over the room. The little help. You can do as well as any- HOW THE "WIRELESS WIZ" clock on the mantel was arranged to close body, if you try. Everything is made XMAS all the circuits just three minutes after so you learn your TURNED EVANGELIST -A eleven o'clock. clear that can in STORY. "Where is the projection lantern that spare time, regariless of where you (Continued from page 565) threw the face above the flames ?" I asked, live or what your work. No books in arranging it ?" he asked exasperatingly. seeing only a concave mirror in evidence. to buy. Thus he had started the ball rolling I was trying to show how much I knew himself and I awaited developments with of his methods but imagine my conster- There's big Money in Electricity. interest. The "Wiz" switched off the nation when the "Wiz" replied. Get after it by marking and mailing lights and the three of us settled down "Wrong, old man, that concave mirror the Coupon today. Finding out costs of thoroly healthy did the trick. See this picture here," and behind a like number you nothing. "jimmy pipes" in front of the flaring gas he pointed to a picture similar to the une log that the "Wiz" had thoughtfully in- we had seen. "Well, this lamp illumina- stalled in an imitation fireplace. ted it brightly and the concave mirror took MARK THE COUPON NOW appeared to he "feeding" No- the reflection and focused it at a point Team The "Wiz" rI - lan (in the language of the classics), for just above the gas log. No screen is nec- INTERNATIONAL CORRESPONDENCE SCHOOLS he was putting up the worst argument I essary and the object appears to be sus- Box 5327 a SCRANTON. PA. heard and leaving all kinds of open- pended in mid -air. A fine illustration of I can quality for ever the before bwhichtImark X. the maw of oblivion take all this effect is to light a focusing electric ings. "Let ELECTRICAL ENGINEER Commercial Law this silly nonsensical rot about Christ- light as used in automobile headlight in a Electricie, l'HEEICAL ENGINEER dark room. The globes of these lamps are Telegraph Expert SALESMANSHIP mas spirit," Polar finished just as the tiny Practical Telephony ADVERTISING MAN on the mantelpiece struck the hour nearly a perfect sphere and the reflection Electric Wiring Window Trimmer clock Electric Lighting Show Card Writer of eleven. The "Wiz" was gazing intently from the inside of the glass will cause Electric Railways Outdoor Sign Painter fire Nolan followed the di- a second filament to be seen inside the Electric Cesigner RAILROADER into the and MECHANICAL ENGINEER ILLUSTRATOR rection of his gaze and awaited a reply to globe but upside down. For this reason Mechanical Draftsman ARCHITECT mount in Ga. Engneer Areblteet end Draftsmen his epithet. it was necessary to the picture CIVIL ENGINEER GOOD ENGLISH In silence we sat, one -two -three min- a reversed position so it would appear Survey infend Mapping Teachers Course Metallurgist Common Sehool Soblssb utes when-what was that! We all stif- right -side up when focused." STATIONAKY ENGINEER CIVIL SERVICE Even when explained it yet appeared Concrete Engineer R.ilway Mail Clerk fened slightly. as faintly at first, then Structure Engineer AGRICULTURE louder, came the sounds of sweet chimes marvelous, and half -jokingly I suggested BOOKKEEPING Navigator Spanish the ought to become a mis- St her sod Typlat Pooh, Raising German playing that old, old wonderful hymn, that "Wiz" Cert. Pub Accountant ACT11Rt)RII,1:S rash "Adesta Fidelis." Quaint and mysterious sionary and try some of his stunts on the Railway Accountant Auto Repairing Italian it sounded as the notes rang out and re- heathens. he solemnly replied, "we don't Name verberated through the confines of that "No," Occupation. f any, need heathen missionaries ; we need Euro- and Employer room. Street Imagine the scene. The glowing gas log pean missionaries just now," and with and No these words still ringing in my ears I left faintly flooding the room with its ruddy State -black shadows into -accompanied by the Wizard's best wishes City light casting purplish If name of femme you want not In this list. write it below. every corner. The three of us, sitting like for the season. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 616, THE ELECTRICAL EXPERIMENTER December, 1916

MARVELS OF MODERN PHYSICS. (Continued from page 567) Don't Wear obtained in a sulfuric acid solution, be- a Truss tween electrodes of a number of diférent BROOKS' APPLIANCE, metals the modern scientific -lead for instance. The brush re- invention, the wonderful moves the film deposit as soon as it col- new discovery that relieves lects, and allows the glow to be visible con- rupture will be sent on trial. tinuously. Of course it must be remem- No obnoxious springs or bered this light is not from sparks but from pads. Has automatic Air SEE THIS IDEAL GIFT a chemical source, nor is this Cushions. Binds and draws DON'T SEND A PENNY, EXAMINE WATCH FREI. light a prac- the broken parts together as tical one -far from it. The phenomenon is you would a broken limb. an actual reality, and is proof that light, No salves. No lies. Dur- JEWEE5o with at least a negligible amount able, cheap. Sent on trial "$a1taF $ of tem- to prove it. Protected by mom perature radiation can be produced. Catalogue -the one standard railroad watch "That's Guaranteed U. S. Patents. for Life," thin model, all sizes, adjusted to positions, The production of a light, equalling sun- and measure blanks mailed ad usted to lsochronism, adjusted to temperature, free. Send name and ad- adjusted to the second. light in diffuseness and color value has long dress today. been an unachieved goal. The fila- Write for FREE Watch Book carbon C. BROOKS, Marshall, Mich. shows Today E. 203 State Street, newest watch ease designs in 4- colors. READ the so- called ment gives a yellow light, tungsten gives a SECRETSS of watch making. READ bow you elm save from ONE THIRD to ONE HALF of your money -Bu Direct," cut t whiter light, and the arc light is distinctly thewholesalejeweler's profit. Readabout NEWBraestet Watches. bluish. EASY PAYMENTS to suit you. Write today Your The nearest approach to sunlight 1IIIIaIIIp!/ii name on a postal hringe the FREE wale), book. is given us by the Moore light. This light, What Nature Has Forgotten SANTA FE WATCH COMPANY, Dept. D -29, Topeka, Kan. it will be remembered, is the vacuum tube type, that is, it consists of a long tube in His Tailor Builds with Cotton which can be sealed any desired mixture Are you a "tailor- made" man? Are your of sunken-in hiding'ehindythe rarefied gases. A voltage of 10,000 to 12,- tailors art? If they are, remember this your sunken cheek, !Meg- 000 causes the lamp to glow with a soft ringed eyes. and the naturel invol- NTINENTAI°GeEÀcgtlalnted" untary prinking from any test of diffused light, the color of which strength, eveal the deception OUR DECEMBER OFFER depends our tailor-made bluff Is called the on the proportion of the various gases pres- instant you tecklesomethingresuir- Each month to acquaint our ing the energy of a man. friends with Continental values, ent in the tube. Practically, it is of much mop Fooling Yourself- we offer an exceptional bar- You Fool Nona Else! gain In some popular article. use in matching colored cloths after night, on Your For December our special is Bond Flesh Frame! BOYS' a wonderful hockey GIRLS but on account of its revolutionary char- Go to It Nature's Way! and -skate Send 4e in Stamps to cover mailing shoe outfit at a big reduction. acter and high initial expense it is not in the femou. book Intelligence in Physical and Health citur,," THIS REGULAR general demand. The interesting thing to tltten by the strongest man in $5,00 $3.95 with he world. It is Free, SKATE note is that this is a form of low tempera- & SHOE OUTFIT Coupon LIONEL STRONGFORT, When ordering give size of shoe and specify boys' or girls'. ture radiation. It is far from being cold PHYSICAL CULTURE EXPERT All delivery charges prepaid by us. Send your order today. CONTINENTAL MONEY -BACK light in the absolute sense, but it has been No.17 Park Bldg., Newark, N.J. purchase. GUARANTEE with Bank reference: U. S. Mtge. & Trust Co. of found by actual measurement that the tern - N. . WRITE FOR FALL AND WINTER CATALOG "E.E.' Watch Next perature inside the tube is only 30 degrees for Month's Special ..;i Get up -to -date in Rouen Wm- or 40 degrees C. Altho yet in its infancy, Save TINE, MONEY, tUNTINENIAi 1P/ 1/ 7 Lw' oß and MATERIAL by using sPOaitns.s05 - ° the efficiency of the Moore vacuum tube ElectrlVlállS 86 GEN BINE BLDE PRINT IIIaIIDaktosEsTAJt sera 6ilKSAinitp oy ha DRAWINGr, eseryg all the may be as high as 0.7 Watt per candle. latest diagrams and connections (mown in house wiring-even diagram 15, most 125 ,Street. N C1 O/' and, connection se used by tiret elms electricians for ow This compares quite favorably with BELLC 8AuS inuRae eesarawioes E orm other aI1gnd (9s c. Tienen drawings are nothe o .he end or lamps as may be seen from flexible book 1y x [n' for in using on the job. Send for the following them, and they don't make you morecon et a wireman dnd eney table : a hundredrefu d d-y their 'tat d co return them and money willwou refunded-you can't afford to be without them. ONE DOLLAR mear post paid. $60 A WEEK AUTOMOBILE Watts per spherical Cp. PATENT SPECIALTY COMPANY You can make $fü a 462 Sanchez Street San Francisco, Cal. week and get Free Carbon filament 4.00 Auto. I want hustlers, money -makers, to work Enclosed carbon arc 2.00 with me to advertise, sell 'Moore light (neon gas) .70 and appoint agents. Big- Learn Wireless Under Marconi gest thing in years. City Gas filled tungsten .63 conveniences without Co's. Chief Instructor plumbing. Used in any room. Titanium arc .15 vow'p Sells on sight. Demonstrating Evening study. All modern equip. tub furnished. Folds small, self- empty- The problems of illumination embrace a ment. Send for folder E." ing, non.icnkable. Guaranteed 10 years. consideration of the whole field of light AGENTS phenomena EASTERN DISTRICT, Y. M. C. A. MAKE SALES EASILY from the physiological reac- MARCY NEAR Two sales daily means $60.00a week. Leggett, Ohio, "Worked AVE., BROADWAY, BROOKLYN two hours, took two orders, profit $10.00. ' Hayhurst, Nebr.. tions on the eye itself, to the deeper phys- 13 minutes from New York City Hall "Took 11 orders in 41¢ days -profit $55.00, ordered 12 more ical and mathematical problems of the na- tubs." Manning, Iowa, "Sold 10 tubs in one day -profit $50.00." Deflut Nebr., "Sold 12 tubs in three days -profit ture of light. The study of illumination 460.00." And hundreds of others making big money. ?Open canto homes have no is only a special case of radio transmission. 50 A MONTH bath tubs. Experience and capital unnecessary. Credit Bnya a given to the right man- Gat full particulate and "epeeist plan;' all Fasa We can even carry the study back to the H. S. Robinson, Pres., THE ROBINSON CABINET MFG. CO. Visible Writing 42420 Factories Bulldin minute electric charge -the electron, from TOLEDO, OHIO L. C. SMITH which point the most fundamental distinc- Perfect machines only of standard size with keyboard of tandard universal tion may be drawn between temperature arrangement --has kBack-spacer-Tabu- lator--two color ribbon --Bail Bearing a Month radiation and chemiluminescence. In the cónetruOhne eve uD ratio nva- 50 ce FIVE nd The master- former, the energy of the electron is trans- price guaranteed. Catalog and special piece of watch mitted to the whole molecule, and small price sent FEEE manufacture- adjust- H. A. SMITH ed to the second, positions, tem- light waves and larger heat waves are 738.231 N. 5th Ave CHICAGO, ILL perature and isochromsm. En- given cased at factory into your choice off at the same time as shown in of the exnuisite new watch cases. Fig. 3. The vibration of the molecule generates the heat waves, while the motion of 21 Jewel the electron generates the light waves. In the latter case, the energy of the elec- "PACIFIC RADIO NEWS" both tron is not communicated to the molecule men wad All8fo Burlington A REALITY AT LAST The great Burlington Watch sent on simple request. and the light alone is given off (Fig. 4). Pay at rate of $2.50 a month. You gey the watch at This is cold light, in the absolute sense. the same price even the wholesale jeeler must pay. In The time is now at hand when you can get Write Today for Free Watch Book the phenomena mentioned above, the some startling radio facts from the Pacific See handsome color illustrations of all the newest temperature radiation is not totally absent, Coast. The "Pacific Radio News" is published designs in watches that you have to choose from. but merely very low ; and in practise it by the San Francisco Radio Club and the first Your name and address on a postcard is enough. issue will be ready for distribution on January Get this offer while it laste. Write today. may never be possible to wholly separate Ist, 1917. Members of the club have contrib- Burk glon Watch Co. Dept 7449 19th & Marshall BIr1. Chicago the two. I-Íowever, there is now but little uted 48 pages of FACTS, some startling stories doubt but that any great advance in the will be published in the initial issue. The Great Moorehead-DeForrest audion tube in- future will be along these lines, and the junction, together with a full account of the Are You Looking for Something field is a fruitful one for research at legal proceedings will be the special feature of present. the first issue. Price per copy is 10 cents, that will prevent your Eye Glasses and delivery guaranteed. Send for your copy at [This is the tenth paper of a series pre- once as only 10,000 copies are being printed. Goggles from steaming, due to tempera- pared exclusively "The Electrical ture for Ex- Address changes? Then you need our Steam perimenter" by Mr. Rusk.Ed.] Preventer, price 50c postpaid. 4i PACIFIC RADIO NEWS" Moon -Power Mfg. Co., Box 673, Plainfield, N. J. The Parcel Post service is using electric 1580 Grove Street, San Francisco, Cal. delivery trucks in many of the large cities. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 617

ANENT THE AUDION. EFFICIENT AND ECONOMICAL Leatle0A1NTS OW CARDS (Continued from page 574) METHOD OF UTILIZING THE ARMSTRONG AUDION SYSTEM Get into this distance work. Eighteen months after the G7aee license was acquired New York and San FOR DAMPED AND UNDAMPED interesting, profitable WAVES. 1 and fascinating business Francisco were in voice communication. page where the field is not crowded. The much despised Radio Art supplied the (Continued from 575) Thousands of cards used weekly. necessary; and now watch those telephone summer, while all the spark stations along Department stores, clothiers, movie engineers tumbling into Radio. the Atlantic Coast came in very clear. The shows, et,., pay big prices -work done quickly aad easily -profits large -hundreds of jobs all The Ultraudion was exhibited in 1913. receiving station in this instance was at around you. My students can more than pay for course Mass. doing jobs in spare Lima while studying. Increase your Within six months Washington heard Quincy, into business for yourself. Honolulu's radio signals by daylight by its The wave length range of set "A" should salary. get a better job or go means. And to -day no long distance re- be from 2,500 meters to approximately Earn $18.00 to $45.00 a Week-Easily ceiver in the world but employs, under some 13,500 meters, while the wave length range I will train you to fill a high salaried job. I personally correct every lesson. 17 years' successful teaching. one of its many aliases, the grid audion, of set "B" should be from 200 -2,500 meters. Thousands of successful graduates all over the world. No coo no job too big for mY graduates. black ! If difficulty is experienced in getting down town small, tho some bulbs are painted Get my training -start now. And last there's the oscillating Audion or to 200 meters, the inductance of L2 should "Oscillion," as a source of high frequency be decreased, but not enough to destroy the Big Money in Card, Sign and Bulletin Business No other profession pays such profits- -work ornes to you in abun- generation of my early dreams coupling. Close coupling is required be- dance--no jcb will stump you. My students learn ail. All the new - -another ewelkst designs. come true -first announced in the spring of tween L2 and L3 for good results, and if hat,ow t run the FREE Outfit ness, how to hire men, Guarantee 1914. In the fall of 1915 a bank of 500 the inductance of L2 is decreased, the coup- how Write now ter spe- act givespyou arom- guarantee to "power tubes" (Oscillions, I prefer to call ling must essentially be tightened or closed. cial literature and to seining. You can to priceeon 6 courses-- fi1nish y course ' n a at $86.00 terms, testimonials, short time. Read $175.00 thly. them) -sent the telephone engineer's voice This system has been compared with other lesson nd The demand for don't fcomgreater proven Free Outfit ffer. out o atjob r work et trained from Arlington a quarter of the way hook -ups and has, in every instance ALL - FRE-Don'tE low wages any longer- than the supply. around the globe. And already there are to be superior in many ways, especially with delay, act cuickly. Oct Started Now and effi- being constructed single oscillion bulbs regard to simplicity in operation, Detroit School of Lettering, O7lá Detroit, Mich. which can put one and two kilowatts in the ciency. This circuit has been thoroly tested antenna. Here we slide into prophecy, and dare state that as a source of radio power, the Audion will play an even greater rôle than as receiver. The little grid has made good. [Judge Learned Hand of the Federal Dis- trict Court has enjoined the Marconi Wire- less Telegraph Company of America from IDEAL BLERIOT MONOPLANE IDEAL TAUBE MONOPLANE IDEAL CURTISS Military Tractor using in any form the audion detector or Exact Duplicate in Miniature of Exact Scale Reproduction of the Exact Scale Miniature of machines amplifier, the patents of which are held by the famous BLERIOT XI, that famous GERMAN and AUS- supplied made the first successful flight TRIAN MILITARY machines. and i p in large numbers to the De Forest Radio Telephone and Tele- across the English Channel. Flies Rises from the ground by its England. Guaranteed to rise from 75 feet and more. Easy to build. own power and FLIES. Outfit the ground by its own power and graph Company. The injunction is to run Outfit complete in box ready to complete in box ready to put FLY. Outfit complete in box ready perpetually and is dated October 12, 5916.] put together $4.50 together 54.50 to put together $5.50

nnemua11.... m. M uuunumnuuaoe nuunnn, mllm111 aamm11a111111m0mllmmmmmmOm _ a,uuouunmuuum1ommnnmm11mnmm1ununnmuuunuuumumwommumuwnnnuaum. WITH THE AD MAN. How many of these -and which Greetings ! May your Christmas be a very hap- -will you get for Christmas ? _ py and joyous one. May it be happier for the good which you can do You'll probably get the ones you ask for. Your paren s for others and for what they are try- want to give you this gift because they know you'll spend pleasant, profitable hours this winter building these wonder- IDEALNIEUPORTMONOPLANE ; ing to do for you. Faithful Reduction Model of the May it be happier as a result of ful models, and you'll have greatsportflyingandracing them. femme NIEUPORT Monoplane, Thousands of boys this Christmas are going to get one of the leading types now used your interest in electricity just as we in the EUROPEAN WAR. Self - are made happier by our knowledge riairg and flying. Outfit complete that our efforts in introducing THE In box ready to put together, $5.50 ELECTRICAL EXPERIMENTER are being Ideal Model Aeroplanes appreciated. If you are one of the lucky boys who already own one, be sure to get another one of our models to complete your squadron. It is our sincere wish that every We send you all the parts and you can have lots of fun puttirg reader will be a reader next Christ- them together, making three -foot model aeroplanes that fly far and fast, and rise from the ground by their own power -just Like the b[g mas, and help the cause of THE aeroplanes. ELECTRICAL EXPERIMENTER (both the The aeroplanes that you see illustrated on the upper part of this personal and the publication) to the advertisement are exact models of the big aeroplanes. They fly from end that we may have more Edisons, 60 to 120 feet. The others, such as the Cecil Peoli Racer, fly from 300 to 1691 feet (the official record). CECIL PEOLI RACER Teslas, etc. Ideal Aeroplanes afford not only great outdoor sport, but also teach Mr. Cecil Peoli flew this Racer As a Christmas gift we can offer valuable lessons in the great new science of aviation. What you learn 2500 feet. (Official Record 1691 feet.) promise today may aerie your country in the future. It is easily constructed and will you none but our to try to make beautiful high flights of 1000 excel our efforts next year in the They're the Gift Every Boy Wants feet or more. Try to make a record with it. Outfit complete in box production of a bigger and better You can easily build these models by following our simple, easry ready to put together.. $3.50 magazine. understood building and flying instructions. Scale drawings and Assembled Peoli Rater $8.50 If you would give us a supreme instructions alone for "Ideal " 3 -foot models at following prices: Curtiss Military gift, have it in the form of your Tractor 25c friends' subscription and the patron- Curtiss Flying Boat 24c Curtiss Hydro- = age of yourself and friends of our aeroplane 3.1c advertisers. Nieuport Monoplane 2 le ,t It is only a little gift, but we know Bierlot Monoplane_ .1.lc it will make for a happier Christ- Taube Monoplane ...... //D/4»Óti`k`+ Wright Biplane 25e ií:. = mas and a really joyous year of Cecil Peoli BLUE BIRD Racing 1917 for us all. Racer 25c AEROPLANE A handsome, graceful 22-inch Flier. MILTON HYMES. SPECIAL Mo into to a height of MO feet and files OVER 300 feet straightaway. al111o111111111111111111111m11111111mmmnnn ,annm11mno1mm1mmmuuuanunnnoe11 111111111 1 1 11an. Build a fleet!

u 1 1 1 1 1 1 u u Packed and delivered ready to fly Swsurvuunnauunuunanus, enunnnnnnnnuuaunuuummm11innnanaananunauns ni: Get a complete with Multiple Winder, special set of abut Foot Gear and illustrated flying CITY FLOODED BY FLOOD plans for instructions $1.50 LIGHTS. $1.60 A battery of forty -one powerful search- order to us, enclosing :the requlrsd HOW TO GET THEM amount of money. We prepru lights, each being of more than 25,000 can- Go to the leading toy. sporting transportation east of the Miss-s- dlepower, located on a long pier in the har- goods, or department store in your $fpni Ricer. Get our illustrated 50 page Aero- town. Ask to see "those Ideal as to make plane Book, containing full informa- bor of Seal Beach, Cal., now provides il- Aeroplanes." If your dealer can't Order Today sore obi tion, prices for parts, complete models, lumination for the city's entire water - front. give you what you want, send your exactly what you want. etc. S.mply write your name and address on the margin of this page, tear it off, and The illuminated water -front may be seen. mail with 5c. and we'll send you a copy of far out at sea, while the searchlight beams Ideal Aeroplane & Supply Co. this interesting book. provide illumination for the city's environs. 76 -82 West Broadway New York, N. Y. You benefit by mentioning "The Electrical Experimenter' when writing to advertisers. 618 THE ELECTRICAL EXPERIMENTER December, 1916

THE DELINEATION OF INTERNAL This diagram can be discerned forth- ORGANS BY A NEW ELECTRICAL with by holding the wax film against a WANTED MENT METHOD. strong light, and can be converted into an (Continued from page 610) ordinary photograph such as those here X75 TO$300 two- thirds the size of Screen A, and is shown by processes of a type quite famil- A MONTH ! held by wire supports (and movable along iar in ,various applied arts. in the air in a horizontal position Principle. Demand for capable them) The Underlying automobile and tractor men far exceeds the 4 or 5 feet above the center of Screen A. So far this account has been confined to supply. Our graduates secure ood paying positions as Salesmen, Demonstrators factory Testers, Gar- The primary result of this arrangement a description of the results obtained and age Managers, Drivers and tractor Experts. is that any electrical field emanating from the machinery employed. The why and $50 Course FREE Screen A is always at right angles to that wherefore of the whole process, or rather, Only six weeks required to train you in this great of Screen B. The fields themselves are the underlying facts, are quite another school. Most complete instruction. Instructors po respectively charged by the currents derived matter. Course ibn Tractor and ILiebting Engineering Free. Write today for our big iras Book from the batteries A and B with their al- When the results are compared with the and $50 irae aokolarahla Certificate. ternating visible means by RIME'S AUTOMOBILE TRAINING SCHOOL interrupters. which they are reached, Largess Auto Training School Consequently, it is open to the operator they seem at first quite incomprehensible, In Me world. 512 E TIMSL. KantClt, Mo. to choose at will the section of the body if not incredible. It is certain, however, which shall be brought within the influence that they can be and are attained, so it of the combined electrical fields, as also only remains to endeavor to account for the plane of the body which the lines of them. The inventor, it was gathered, be- RS,-Lp s S force in Field A shall effect. lieves that the results are primarily due to U STRATIó The appliances used have now been de- the fact that the process interposes between scribed so far as is possible without going two alternating electric fields of equal into minute details, but one further point strength -and at the precise point where must still be mentioned. At given instants they meet -a third electric field, whose of time during the operation of the ap- facultative potential force is thus released 5 pliances the current in electrode B is very and can be converted into dynamic power. unstable, consequently it has placed around It is this released circuit which operates ELECTRICITY! it a wire coil, which insulates it from at- the recording needle, and the pattern tapt mospheric electricity. out on the revolving cylinder varies with HERE'S just the book on The Method of Operation. the shape of the organ furnishing that cir- Electricity that you need The machinery thus described is operated cuit. to answer your many ques- as follows: The foregoing is one legitimate way of tions-to solve your knotty The first step is place the in summarizing the inventor's view in sim- problems, to teach you new kinks, to to patient be your memory for tables, rules, the right position in relation to the two ple language. Another would be to say formulas and other Electrical and screens. He must be quite close and head that the force operating the needle is the Mechanical facts that some people try on to A, balance which remains carry in their heads-and fail. the vertical Screen and the organ of current after to to be examined must be directly under the horizontal current from electrode A, With this "Little Giant" I. C. S. Elec- trical Engineer's Handbook in your Screen B, though at a considerable dis- reinforced by the electricity contained in pocket, tool chest, on your work tance from it, and at the same time present the organ through which it has past, has bench, drawing table or desk,desk an hour the desired plane towards Screen A. met the descending current emanating from or a day need not be lost up" some forgotten rule, some unfamiliar fact; The right position having been secured electrode B. you'll just turn to the very complete index and the following steps are taken : (1) An in- However the inventor's view be ex- get it in a jiffy." Just a few of the subjects treated tact wax sheet is put upon the recording pressed, it involves the supposition that are: cylinder; (2) the rate at which the cylin- every organ in the body constitutes and Electricity and Magnetism ; Electrical Symbols; Batteries; Circuits; Magnets; Direct and Al- der shall revolve is determined; (3) the originates a separate electric field, and that ternating Currents; Dynamos and Motors; appliance which regulates the rapidity of the facultative dynamic power of this field, Belts ; Shafting; Electroplating ; Electrical the alternations is adjusted; (4) as also its shape, varies precisely Measurements; Meters; Arc and Incandes- the cur- with the cent Lamps; Mercury Arc Rectifiers; Trans - rents from batteries A and B are simul- constitution and shape of each organ in formera; Insulation; Electric Cars; Single and taneously released, with the immediate re- question. Multiple -Unit Control; Transmission ; Rail sult the recording begins But, Welding; Tables of Wires-Sizes, Capacities, that cylinder to after all, very little is at present etc., -Mathematical Rules, Formulas, Sym- revolve while the hammer needle moves known concerning organic tissues as a bols; Tables of Constants, Equivalents, Roots, across it steadily, giving rise at each stroke source of electrical force, and in any case Powers, Reciprocals, Areas, Weights and to Measures; Chemistry; Properties of Metals; a slight click. This movement of the the fact remains that it is on this theory Principles of Mechanics; First Aid, etc. needle is allowed to continue until it has that the inventor and originator of the pro- The Electrical Engineer's Handbook is one of 22 twice traversed the cylinder from end to cess has worked out his discovery and is at I. C. S. Handbooks covering 22 Technical, Scien- end, and the currents are then cut off. present endeavoring to perfect it in respect tific and Commercial subjects, all crowded with What has happened in the meantime is of mechanical details. value. They have the contents of a full-size book condensed into pocket -size ready to go with you that the current from battery A has While the greater part of the process anywhere and be at your instant command. reached electrode A, and has thence been has been developed by constructing a novel They are substantially bound in cloth, red edges, projected from goldleaf stamping, printed from new, clear, read- horizontally all parts of theory and converting it into a practise, a able type on good quality book paper. There is Screen A as an electric field. The same good many of the results so far obtained an illustration at every point where a picture thing has happened in regard to the cur- are due to experiment. It has been found, will help. Hundreds of thousands have been B, sold on a money -back guarantee of satisfaction. rent from battery but the direction of for instance, that the appliances must be the field projecting from Screen B has been tuned for different organs and different The regular price is $1.25, but for a LIMITED vertically downwards. tissues. TIME you can buy the ones you want, post- What has also happened is that the two In other words, the rate of alternations paid, delivery guaranteed, for only 50 cents. fields have met at right angles, and as they in the currents, and therefore the force are of precisely equal strength, and are of each electrical impulse, must be varied You Run No Risk! Money Back if Desired! synchronized in respect of alternations, it according to the rate of vibration of the International Correspondence Schools might be expected that they would have tissue molecules. Thus the electrical force Box 6328, Scranton, Pa. precisely neutralized one another, and that residing in blood is very small; so, when r TEAR OUT MERE, conseouently no exhibition of dynamic force blood vessels are to be delineated, the al- would be obtainable from them. ternations must be very rapid. Contra- INTERNATIONAL CORRESPONDENCE SCHOOLS But in practise this is not what occurs. riwise, since the electric force residing in Box 5 3 2 8 , SCRANTON. PA. On the contrary provided that the body heart muscle is great, the alternations must I enclose $ for which send me postpaid the examination is that of a living per- be slow when a heart is to be Handbooks marked X, at 50c. each. I may return any or all under delineated. and get my money back within ten days from receipt: son (or is one in which merely somatic, The foregoing circumstance is the reason Electrical Engineer's Advertiser's not cellular, death has occurred), an effect- why the pictures' shown in this article are Teleph.and Teter. Engineer's Business Man's Mechanic's Bookkeeper's ive current from below always manages so devoid of detail. In other words, the Steam Engineer's Steno. and Correspondent's Westinghouse Air Brake Salesman's to reach electrode B and thence passes to process, so far as it has at present been Civil Engineer's Window Trimmer's the detector mentioned as being among the developed, never delineates more than one Coal Miner's Cotton Textile Worker's Concrete Engineer's Farmer's apparatus in the cupboard. type of tissue on the same occasion, and the Building Trades Poultrymans speed Plumbers and Fitter's Mariner's The result, therefore, has been that the required for some tissues has not yet Chemist's Automobile hammer needle mentioned has been put into been learnt. This fact, however, can hardly operation and has tapt out on the revolv- be regarded as a total disadvantage, for Name ing wax sheet below it, a diagram which from the surgical point of view it helps to Street and No. precisely resembles the outline of the liv- make the discovery of immediate value. ing tissues lying vertically below Screen 'Take, for instance, the picture of a kidney City - State B. here shown, or that of a liver.' In the one You benefit by mentioning "The Electrical Experimenter ' whets writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 619

case the instrument was tuned for kidney tissue, and in the other for liver, and in 20 Lessons of Course neither for blood or pus; consequently the outline of the two organs is shown quite clearly, and the effusion is represented by in Drugless Healing S- T -O -P! a patch of different tint. So far we have not mentioned the dis- coverer's name. It is James Shearer, aged thirty, at present a sergeant in the Royal FREE: We hereby present Army Medical Corps working at a casualty Positively and absolutely clearing station. By birth he is a Scots- free to you ! Not one cent the greatest bargain man, but he received his later education in to pay now or later. To a America, where he graduated M.D., Ch.M. limited number and for a of D.C., in short time only, we are ever offered in elec- at the University Washington, giving20 Complete Les - 1907. On his joining the R.A.M.C. he could sons in Chiropractic,- not be given a commission, as the medical absolutely FREE. trical literature. There is no cost degree he holds is not one of those recog- to you at all for l nized in Great Britain, but as soon as it these ccmplete A complete volume was found he was possest spe- lessons. But you that of must act quick! cial electrical knowledge, and believed that This rea arkable offer of the Electrical he saw a way in which it could be utilized is strictly limited. As for purposes of war, he soon as a certain num- the the was given of these sets of Experimenter opportunities of developing his ideas by ber 20 lessons have the commanding officer of the hospital of been given we bound in rich, dark his unit (Lieutenant -colonel Clements), shall withdraw the offer. Don't wait a min- with the approval of the Director -general ute. Act now. green linen, stamped of the Medical Service in France, Sir Ar- Those Lessons Teach You How to Treat Headache How to Treat Catarrh thur Sloggett. How to Treat Neuralgia How to Treat Epilepsy with gold letters at How to Treat Constipation How to Treat Hay Fever STATEMENT OF THE OWNERSHIP, MAN- How to Treat Indigestion How to Treat Paralysis the extraordinary low How to Treat a Sprain How to Treat Pleurisy AGEMENT, CIRCULATION, ETC. How to heat Dyspepsia How to Treat Asthma Required How to Treat Rheumatism How to Treat Gout price of by the Act of Congress of Aug. 24, 1912, How to Treat Lumbago How to Treat Jaundice of THE ELECTRICAL EXPERIMENTER, published Monthly at New York, N.Y., for Oct. 1, 1916: Why We Make This Great Offer State of New York, County of New York, ss. We want the public to know the real truth Before me, a Notary Public, in and for the about drugless heal ng. We want you to con- State and County aforesaid, personally appeared vince yourself by actual and practical demonstra- Milton Hymes, who, having been duly sworn' tion just what a mar"elous curative force may be $ .25 placed at your command. We want you to see for according to law, deposes and says that he is the yourself what tremendous opportunities have been Business Manager of THE ELECTRICAL EXPERI- opened to Doctors of Chiropractic. You will nee MENTER, and that the following is, to the best what hal been done. You will see what can be of his knowledge and belief, a true statement of done-by you! A Diploma in Chiropractic offers Postage on7 Ibs.is extra you a profession of dignity, prestige, influence the ownership, management (and if a daily' and wealth. If you are ambitious and can read, the paper the circulation), etc., of the aforesaid pub- way to saccess is open to you. Take advantage lication for the date shown in the above caption, of this lifetime opport mitt'. required by the Act of August 24, 1912, em- bodied in Section 443, Postal Laws and Regula- tions, to wit: Also Free! Two Sets of 1. That the names and addresses of the publisher, editor, managing editor and business manager are: Charts, Value $31.50 Publisher, Experimenter Pub. Co., Inc. As an extra inducement for prompt action, 533 Fulton St., New York we are giving a complete $15.00 Set of eight Editor, H. Gernsback. ...233 Fulton St., New York Anatomical Charts and $16.50 Set of Nerve Managing Editor, H. Gernsback and Pain Area Charts, absolutely free. Also 533 Fulton St., New York for a limited time, our Business Manager, M. Hymes 233 Fulton St., New York Hew Illustrated Book 2. That the owners are (give names and addresses Healing of individual owners, or, if a corporation, give On Drugless FREE its name and the names and addresses of stock- Doctors of Chiropractic throughout the holders owning or holding 1 per cent. or more United States are making a big success. Let the total amount stock): us tell you about them. Let us prove how you should of of easily make $200 to $500 per month and more. Experimenter Pub. Co., Inc., Write while this special 20 free lessons offer is 233 Fulton St., New York open. Send your name and address on postal today, and receive boy mail, postpaid, our new illus- H. Gernsback 233 Fulton St., New York makes S: 233 trated Look on Drugless Healing which Gernsback Fulton St., New York everythi ng clear and our remarkable Free Lessons M. Hymes 233 Fulton St., New York and Free Charts offer Write today sure. H. W. Secor 233 Fulton St., New York AMERICAN UNIVERSITY 3. That the known bondholders, mortgagees, and Manierre Bldg., Dept. Chicago other security holders owning or holding 1 per 714 cent. or more of total amount of bonds, mort; gages, or other securities are (if there are OF TEACHING Dyke's ;Book-FREE J , Volume contains twelve numbers, 743 none, so state) : None. 4. two paragraphs next above, giving interesting. iutruetire -tells you wITH pages, 1,226 complete articles, 1,742 That the the to AUTO TRADE; how names of the owners, stockholders, and security bow learn illustrations, 227 questions and answers. to become ,hauffeur and repel, holders, if any, contain not only the list of man. -SEND !OR IT -Teda -N. I WOKINGMODELS 910g.8LLOW S,Mo stockholders and security holders as they ap- A.LDTKE, 225e. .,. CRISIN MANIKINS t . A world of electrical information; pear upon the books of the company, but also, the entire electrical Progress for one in cases where the stockholder or security year; the greatest reference book on holder appears upon the books of the company Send for large as trustee or in any other fiduciary relation, the R E E current "Wireless" -all at a price as name of the person or corporation for whom Catalogue of low as the unbound copies would such trustee is acting, is given ; also that the Books bring. Mind you, the book is durably said two paragraphs contain statements em- Practical Mechanical bracing afiant's full knowledge and belief as bound with heavy covers. You will to the circumstances and conditions under which be proud to have it in your library. stockholders and security holders who do not FOR HOME STUDY We have only 100 copies, therefore be appear upon the books of the company as trus- Best Books for Electri- sure and order today. Shipping weight tees, hold stock and securities in a capacity cians, Telephone Men, other than that of a bona fide owner; and this Motion Picture Opera- 7 lbs. Add a sufficient amount for affiant has no reason to believe that any other AUTOMOBILE postage. person, association or corporation has any in- tors, Engineers, Railroad STARTING ,r,n terest direct or indirect in the said stock, bonds, Men, Motormen, Drafts- LIGHTING Order today to avoid delay or other securities than as so stated by him. men, Automobile MANLY 5. That the average number of copies of each issue Mechanicians, Plumbers, of the publication sold or distributed, through Carpenters, Builders, EXPERIMENTER PUBLISHING the mails or otherwise, to paid subscribers, dur- Sign and Card Writers, ing the six months preceding the date shown also Bookkeepers a n d above is -(This information is required from Civil Service Applicants. COMPANY, Inc. daily publications only.) MILTON HYMES, Business Manager. Book Department, Sworn to and subscribed before me this 15th day F. J. DRAKE & CO. 233 Fulton Street, New York, N. Y: of September, 1916. Dept. 6. 1006 Michigan Ave. [SEAL.] HENRY A. WALLENSTEIN, CHICAGO Notary Public, New York County, No. 15. Sent Postpaid for $1.00 (My commission expires March 31, 1917.) You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 620 THE ELECTRICAL EXPERIMENTER December, 1916

A NATION-WIDE PRESIDENTIAL RADIO RELAY. (Continued from page 569) Detroit trained The Y. M. C. A. Radio School men get preference and tion night, twelve o'clock, local time. Jobs quickly. Think what ft means to learn in the Michigan LIST OF SENDING STATIONS IN State Auto School. Factories endorse announces our School, glad to employ our graduates "RELAY." or offer them territory. Men are needed Wate Central every where as testers, repair men chauffeurs. Station City State Operata Length Time its latest achievement of our graduates start - garage men. Hundreds P. M. m business for 9XE Davenport Iowa Kirwan 425 10:00 a Month 9X55 Rock Island III. Karlowa 500 10:00 $75 to $300 9YA Iowa City Iowa Prof. Fort- 500 10:05 A Wireless Telegraph Course We Earnteach you to handle any auto proposition. Students 9Z8 actually build ears from start to finish, getting factory train - Springfield Ill. Johnson 1,500 10:10 essembling, block -testing, road testing, everything. 9IK Chicago Ill. Mathews 200 10:15 Special course in Oxy- Acetylene brazing, welding and 9ADT Milwaukee Wis. Hartman 200 10:20 by cutting, separate from regular course. All leading types of Lewiston Mont. Campbell 425 starting,Ceding, lighting and ignition systems in operation. SiSix- cylinderlinder 10:25 eight- cylinder King used for road instruction. 7Y5 Lacey Wash. Ruth 425 10:20 Chalmers "6 -80" chassis with 3400 r. p. m. motor, 1917 De- 9BD Superior Wis. Keeler 200 10:35 troiter-6 and Overland Delco System, d i Buick, Hudson. 8JZ Cleveland Ohio Manning 200 10:40 CORRESPONDENCE Packard Twin-6, 1917- Willys- Knight complete chassis. 8ADE Rochester N. Y. Todd 200 10:45 85K Buffalo N. Y. Woodcock 200 10:50 Detroit is Place to Learn --Start Any Time 9ZF Denver Colo. Day 425 10:55 44 auto factories in Detroit and 40 parts factories. We oper- 8YI Pittsburgh Penna. Gilmore 500 11:00 An unexcelled treatise in a series of ate Westinghouse, Autolite Bijur Service Stations. Students 8AEZ Lima Ohio West 200 11:05 get actual experience in hanálin ll kinds of electrical auto equip- 2ZB Schenectady N. Y. Brooks 425 11:10 weekly lessons, complete with charts ment. Just Spraguezits forebylocr. testing °fora . Schooloven tall 9QF Waterloo Iowa Lockwood 200 11:15 purposes Enter time, any day. Three Winston -Salem N. C. Rothrock 200 11:20 and diagrams, and claimed by ex- Glisses daily: morning, after evening. 8NH St. Marys Ohio Mrs. Candler 200 11:25 Factory Co- operation 9ABD Jefferson Missouri Corwin 200 11:30 perts to be the finest course of its We have arrangements with the Shreveport La. Simmons 200 11:35 Auto factories to put them in Money Back Guarantee 5DU Dallas Texas Emerson 425 11:40 kind ever written. Ready for deliv- touch with men who intend going ` E rmantee to qualify 8NF Battle Creek Mich. House 22(000 11:45 ato business for themselves. 9FA St. Joseph Missouri Walker 11:50 ery Nov. 15th, 1916. Buildings- Equlpra not a positionnas chauffeur, re- 6SL Salt Lake City Utah Hart 200 11:55 83.000 additional floor angarager, demon- 6811 thousandso of dollars orth strator, man, Stockton Calif. Macquarrle 200 1200 equipment, plenty of room automobileutomoile dealer aying A. M. And at a price so small that makes orfnew atudenta to work in our new $75 to $300 mthly 1ATY Windsor Locks Conn. Holcomb 200 12 -05 building at 687-89-91 Woodward r refund your money. 9KT St. Anthony Iowa it within the reach of everyone. from OtLa.TR LaPlante 200 12 -10 the world. OIT 9IC Woodstock Ill. Glcenleaf 200 12-15 iii MIT OF TIE ADT0 IOBSílY 911K Anderson Ind. Mystery 200 12:20 orAct Quickly -Don't Walt 9ACE Get full particulars, " Auto St. Louis Mo. Shanks 200 12 -25 Send for Booklet School News" and New Catalog. 8AOZ Royal Oak Mich. Ferris 200 12:30 both absolutely free, or better 8C0 Grove City Penna. Harmon 400 12:35 jump on the train, as hun- 3RD Baltimore Md. Dimling 200 12 -40 Y. M. C. A. RADIO dtillreds have done, and come to 6QJ Sawtelle SCHOOL Detroit the "Heart of the Auto- Calif. Emmerton 200 12 -45 mobile Industry" and learn right. 145 EAST 86th STREET Michigan State Auto School THE REVOLVING MIRROR FOR The Old Reliable School New York City, N. Y. A. G. Zeller. Pres. DETERMINING SPARK 812 Auto Bldg., 687.89 -91 Woodward Avenue, 11 -19 Selden Ave., CHARACTERISTICS. DETROIT. MICH.. U.S.A. (Continued from page 573) focused above, this so that two images can STUDY PRACTICAL ELECTRICITY be photographed simultaneously. In order Through This Extension Course to take a photograph of both images the incandescent electric lamp of the timing ap- Splendid opportunity to master electricity at home 4 essons through an extension course of the School of Engineer- paratus must be connected to the same key These books tell of this wonderful ing of Milwaukee, the most thorough electrical school in which controls the apparatus Read America. with a record of 12 years of success In teaching for producing like fiction, yetaaDabsolutely true. of 30.000.000 Americana support Chiro- practical electricity. Hundreds successful students. the spark image which is to be measured. practic. cured of long - Not a theoretical correspondence course. but identically s e t. same lessons-same Instructors -same attention -as at This is done in order to prevent a blur on Big Opportunity for Ambitious school. You cannot acquire the same proficiency in any the photographic Men and Women. Resident and Home other way at home. plate. The plate should Study Courses. large demand for ctition- e -- $'2,000 to $5,000 eafrly. Small be exposed in the same manner as previ- Easy payments. We Stave ne. WITHOUT requirements. FRE_youii lbert Hubbard's ONE YEAR'S TRAINING ously described. The plate is now devel- Book 'The New Science. Mail postal. get OR rive books FREE. This masterful Instruction puts you on the high road to oped and fixt in the usual manner. The National School of Chiropractic success In the electrical profession -a wonderfully good time of the measured De t El 12 421 S.Ashland Blvd. CHICAGO paying field-woefully short of trained men. Write for spark train is ob- free folder "Master Electricity at Home." It explains tained by carefully projecting down two how you can secure a year's course without cost and geMIMMmmms, points out the many opportunities for earning big money lines from the maxima of two consecu- In the electrical field. Don't put it off. Write now. tive peaks until they intersect any portion WIRELESS OPERATORS SCHOOL OF PRACTICAL ELECTRICITY of the standard wave. Knowing 608 Stroh Bldg. Milwaukee, Wis. the time SEE THE WORLD at any interval of the standard image the Positions always open. Good corresponding time of the unknown salaries. Day and evening sessions. peaks Correspondence courses. Wireless is thus readily obtained. If the standard apparatus for home use. Send Yourself to Win curve has a frequency of 1,000 vibrations for illustrated catalogue. Equip per second the time between two maxi- Phila. School of Wireless Teleg. Here is your opportunity to insure mums would therefore be one thousandth 10 Parkway Bldg., Philadelphia, Pa. against embarrassing errors in spelling, of a second and twice this would be pronunciation and poor choice of words. two Know the meaning of puzzling war terms thousandths of a second, and so on. Increase your efficiency, which resultsjin power and success. People are recognizing the value of electricity in all trades. Here is what a cabi- WEBSTER'S You can learn by our modern and original sys- netmaker's journal says of the electric glue tem of instruction every part of the WATCH- MAKER'S pot : as better NEW INTERNATIONAL "While steam heat is good for glue - shop. Yoou cearneoan earn hil a earnning and o or start in DICTIONARY, The Merriam Webster, is r heating, electricity is much better. It costs aftewell-payingg¢pnsr course universal question Good watchmakerer lays i all- knowing teacher, a little to place an electrical glue- heater in demand and earn from 820 to 485 per week. answerer, made by specialists to meet your needs any shop. The comfort men get working in For particulars apply to the 400,000 Vocabulary Terms. New Gazetteer. an agreeably heated glue room in Wisconsin School of Watchmaking, Dept. 3. Stroh Bldg., Milwaukee, Wisconsin 12,000 Biographical Entries. 2700 Pages. summer, Over 6000 Illustrations. Colored Plates. instead of an overheated one, in addition to Regular and the saving in fuel and the increased pro- India -Paper duction, pays for an electrical equipment in CHRISTMAS GIFTS Editions Beautiful 8 -t x 11 Books, each containing fifteen large less time than is often thought possible." colored views. The Mount of Holy Cross and others.

The Rocky Mountain Wonder . $1.50 G. &C. PROPOSING BY TELEPHONE. The Rocky Mountains of Colorado 1.50 With Indian, Bear and 1.50 MERRIAM Instead of annoying the girl any more why Wolf doesn't the man who proposed a thousand times All three postpaid $3.75 COMPANY set up as a teacher of the art? He ought to ONLY A LIMITED SUPPLY know how by this time, and there are millions B. A. OHLANDER, Quincy Bldg., Denver, Col. Springfield, of men that don't. -The Sun (N. Y.) Mass. The Sun is wrong, says Telephone Re- Get the Best view. A thousand proposals that failed are This Complete Set of not worth one that succeeded. Better fol- FREE Drawing Instruments low the of $15.00 Draftsman's Complete Vorking outfit, absolutely free. Per Electrical example the St. Louis man who They do not coat you a penny on this offer. Write for particulars. Experimenter had been proposing for five years to his $150.00 to $300.00 inamorata without success, but who called a Month M, ñ ate°o re Please Send Sample Pages and Free Pocket Maps her up when she went on a visit to Los to $300 a month and Write Today Send for my free Name Angeles and got her "yes" by telephone in book o drafting. No obligations. Write now. Address three minutes. And it cost less than all Chief Draftsman Dees. Di, 8889 the years of bonbons, flowers and theaters. Ens l EaulomtCa.,Chtaase You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER 621 rite ioYou! Read tKídcniaÍkab1c Oííei'! ) I cXøx(ø: `XPERIM CIT , ,ILE(C,pÚR sE /'n'_, r _ l co&yos - - BY SAG ERNSßR , -. H.W.SECOR 5. RSBACK 14. LESC>aRBOURr4 H.W.SECOR_

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, THIRD 10.000 11'Ì (I)- WWI) '. Size The most comprehensive Wireless Course ever printed. Con- This masterpiece contains 160 pages, 400 illustrations. Size_of book 6 %ft x 9." on extra thin paper, so book can tains 160 pages, 350 illustrations. of book 5 " x 9't. Frinted Very fine flexible linen cover. be slipped in pocket. Handsome stiff cloth cover. Price $1.00 if bought alone. FREE with a year's subscription. Price $1.00 if bought alone. FREE with a year's subscription. This is a very limited offer. It may be withdrawn at any time, due to the ä.` -- tremendous cost of paper, which IS JUST DOUBL=2 WHAT IT WAS ONE -ay..' : YEAR AGO. We only have abont 2000 each of these fine books on hand ; after ÿ conditions become normal again. _. *. they are gone we cannot reprint the books until THIS MAY BE TWO YEARS OR MORE. Now is your chance. The publishers of this journal have earned an enviable reputation of giving more than 100 cents' worth for each dollar spent with them. Profit by this liberal opportunity NOW; it may never be made again. HERE'S THE OFFER v Subscribe to THE ELECTRICAL EXPERIMENTER for one year, at the regular subscription price of $1.50 per year (Canada and for- '', 12-16 eign $2.00) and we will send you FREE POSTPAID, either one of the above books. If you subscribe for two years, BOTH BOOKS Gentlemen: WILL BE GIVEN FREE, POSTPAID. ' Please enter my subscription If you are a subscriber at present, take advantage of :his /, to THE ELEC- opportunity anyway. If you do, we will extend i TRICAL EXPERI- wonderful MENTER for the your present subscription for one year term Of year.... . LIGHTNIN Q, for which I enclose here- LMAUE TO ORIER . with This Offer Limited. Act Now You will also send me at once FREE prepaid your book..

12 co es of THE ELECTRICAL EXPERI- EXPERIMENTER PUB. CO., MENTER make a boot 9" z 12" aad 4" thick. This book will weigh 7 lbs. It is the greatest 233 FULTON STREET, reference r"ame Electrical and Wireless Mft NEW YORK CITY ' wo.k an the world. And all for, elI Address

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. 622 THE ELECTRICAL EXPERIMENTER December, 1916

ELECTRICAL "IRON CHINK." The "Iron Chink" enables the plant to EXPERIMENTAL CHEMISTRY. The new electric "Iron Chink," used in put out one million cans of salmon each (Continued from page 582) dismembering fish and in the sanitary pro- twenty -four hours. The electrification of the action that takes place. Record in your cesses of preparing canned salmon for the other canneries is to follow. This will notebook. market, recently installed in a Puget Sound mean a highly increased output and the Experiment No. 24- salmon plant, is a refreshing item to those operation of these immense canneries in a Take who have another receiver and apply a splint visited these industries. thoroughly sanitary manner. in the same manner as Experiment No. 23, and while the action of combustion is going on, turn the receiver up and look into it. Make notes of the color of the flame, and any evidence of a product. From these tests does it appear to you that Hydrogen is a supporter of combustion? Does the splint burn in the Hydro- gen, if not, what happened to it? Comparison of the Properties of Hydro- gen and Oxygen. Will you take a 20 lesson Wireless Course Let us compare the properties of both absolutely FREE -even postage charges Oxygen and Hydrogen. Just as you prepaid? For comparison of the PHYSICAL will receive PROPERTIES of these two gases we find it, cloth A course the following: bound, size that tells you everything you can possibly Want to know about "Wireless" starting off in lesson No. 1 by ex- 1. Both Oxygen and Hydrogen are color- 7 x 10 ins., plaining the Principles of Electricity. The Second and Third 160 pages, 20 Lessons are devoted to magnetism, motors, generators and less, odorless and tasteless gases. lessons, 350 wiring. And then, by simple, easy stages this wonderful 2. Oxygen is sixteen times heavier than illus., 30 ta- Course takes you into "Wireless." Themysteriesof "Wire- less" are unfolded to you by the use of such simple lan- Hydrogen. . bles, with guage so skillfully used, that of necessity you must under - every bit of in- stand every word. Thesubject 'snot treated superficially, 3. The solubility of both these gases in formation on however, for there is a whole lesson devoted to the Theory water are nearly the same, 100 volumes of Wireless y o u and Mathematics of this epoch marking subject To lend can possibly charm to the Course, the last Lesson (No. 20) is devoted water, dissolving 3 volumes of Oxygen, and want, besides to a history of Wireless and the men who developed it. 2 respectively. The wireless course positively cannot be bought, but will volumes of Hydrogen valuable in- be sent absolutely free with a full year's subecriptlon 4. Both gases can be liquefied. formation on (12 numbers) to the Electrical Experimenter at $1.50. Electricity. It's the biggest moneys worth you can ever buy any- For comparison of the CHEMICAL Magnetism and where at any time. Send for it today enclosing $1.50. Sens now before you forget. PROPERTIES. Theory of them 1. We know that Oxygen does not com- -and it's The coupon below is a convenient way. But do it FREE as now. bine with Bromin or Fluorin, but when Hy- THE EXPERIMENTER PUB. CO., Inc. drogen combines with either of these two explained. Publisher elements, namely Bromin or Fluorin, either "The Electrical Experimenter Magazine." Hydrobromic or Hydrofluoric Acid is formed. 2. We find that a splint of wood burns EXPERIMENTER PUB. CO., 233 Fulton St., New York rapidly in Oxygen, but when placed in Hy- Gentlemen: drogen, no combustion is accomplished by On your absolute guarantee that your 20 Lesson Wireless Course is just as des- introducing a lighted splint. cribed by you, you may send me same FREE. You are to send me this Course at once, 3. Oxygen is very essential for respira- all charges paid, and enter my name for a full year's subscription to the Electrical tion, while Hydrogen, though non-poison- Experimenter, 12 numbers, for which I enclose *$1.50, the price of the Electrical Experi- ous, will not support respiration. menter alone. 4. Oxygen is a powerful oxidizing agent, (If a 2 -) ear subscription is desired, enclose $2.85.) while Hydrogen is just the opposite-being a powerful reducing agent. My name is The Argentinian government has sub- My. address is mitted to Congress a bill for the establish- (11) *Canada and Foreign Countries, $2.00-2 years, $3.85. ment of a government monopoly of wireless telegraphy in the Argentine Republic.

1-16 H. P. UNIVERSAL 1-16 H. P. ELECTRIC MOTORS For spark gaps -grinding, polishing, to drive small machinery, sewing machines, fans, etc. Operating on A. C or D. C.- 110 -130V.

No. l00- -$5.00 NO TINSHELL TOYS No. 290-$5.50 Complete with Carborundum Wheel, Buffing Wheel, Cord and Plug Guarantee : Arbors and Pulley. No Extras Whatever Ask Us Money Specifications for No. 100 and 200 For Testimony Back Height to center of shaft, 3% inches Diameter of shaft . X inch of People if Speed 6000 r. p. m. Who Are Length of Motor . . 4 inches Not Bearings, Nickel Babbitt -NOT CAST IRON Using Our Satisfied Body DIE - CAST -NOT A TIN SHELL Motors We manufacture 28 different types of motors. Send postage for catalogue OMEGA ELECTRIC COMPANY, 304 -S Dearborn Street, Chicago, Ill. Radio Call: Chicago, 9 N. Q. (3 toll) P. M.)

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. December, 1916 THE ELECTRICAL EXPERIMENTER

Scientific Exchange Columns you have at the present time some things for which you have no further use. Do you wish to exchange them UNDOUBTEDLYfor 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 70,000 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: Three cents per word (name and address to be counted), minimum space 3 lines. Cott about I words to the line. Remittance must accompany all orders. No advertisement for less than 50c. accepted. We reserve to ourselves the right to refuse any advertisement which we consider misleading or objectionable. Advertisements for the January issue should reach us not later than November 25th. The Classified Columns of "The Electrical Experimenter" Bring Positive Results. Subscribers experiencing trouble in dealing with any advertiser should notify the publisher very promptly. OVER 70,000 PEOPLE READ THIS JOURNAL

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MULTI -AUDI -FONE with special headset (Cost FOR SALE OR EXCHANGE -A Bi -plane FOR SALE-1 inch sending set, $5.75; 2 r, $30.00) and type B. B. Crystaloi (Cost $12.00) for Glider. What have you in Electrical goods and ceiving sets on oak bases, $7 each; phones, $4: sale. Perfect Condition. Cheap for cash. Make other lines? Would like to buy a hot air bal- aerial, $1 ; switches, wire, books, insulators, etc. offer. Francis Blewer, Newark Valley, N.J. loon. Alan Gibson, Niles, Mich. Write H, Vander Venn, R.F.D. No. 12, Box 4, Kalamazoo, Mich. FOR SALE-2" Manhattan Coil $3.50, brand EXCHANGE -800 meter loose coupler, almost new Murdock 2000 ohm headset $3.00 Must dis- new; cyclometer, new; inner tube, new; bicycle FOR SALE-Complete Receiving Set. Owner pose of at once. Send for list. Henry Lehm- siren slightly used for Duplex Tel -Radion or went West. Set consists of 85 ft. 5 wire Aerial; berg, 5116 N. 12th St., Philadelphia. type AA crystaloi, Tel -Radion preferred. Write 18 ft. bamboo spreaders; ground switch and Percy Vettel, Hornbrook, Cal. wires; Ha-nnet L. C. tuner; Holtzer Cabot Have Ferron Crystaloi, 80 ohm receiver, guitar. Phones; Protective Condenser; Antenna Switch; Want electrical books, variables, ground switch, WANTED -Used Hi -tone (Rotary quenched) 2 Murdock large V Condensers; De Forest Au- loading coil, etc. All letters answered. F. H. Gap for 1 K.W. Must be in- first class condi- dion; 2 filament bulbs (new); all insulators, etc. Ransford, Dalton, Mass. tion and reasonable. Cash or trade. H. J. Set cost owner $75. Sell for $30 cash. This WANTED-An 8 volt, 10 amp. dynamo of E. I. Patterson, care General Delivery, Seattle, Wash. set was used only 3 months, everything is nearly Co.'s make. Earl Servan, Lumberton, N.T. FOR SALE -Electro coupler, $4; Electrolytic new and is perfect. Can be seen at P. E. Ben- FOR SALE -Complete wireless set; very cheap. Interrupter, $2.20; 1,000 ohm receiver and band, nett, 127 ¡'remont Si.. Boston, Mass. Will send 5 and receive up to 2,000 miles. For $2.10; Electro key, 80c. Goods sent postpaid. WILL EXCHANGE -First class Wireless Set price and full particulars write to W. Bedell, James Green, Jr., Orangebury, S.C. for late model Indian Motorcycle or Saxaphone. 35 Hooker Ave., Poughkeepsie, N.Y. Also will exchange cornet for clarinet. Paul FOR SALE-One small 110 v. A. C. Motor, Anderson, Box 214, I.amoni, Iowa. FOR SALE OR EXCHANGE -Eight General El- $2; Type "S" dynamo motor, $3; Gas engine ectric 110 volt alternating current arc lights cost magneto, $5; Electro loading coil, $2; 4 cylinder FOR SALE-Duck Navy Tuner, new, worth new $25.00 each. Will sell cheap or exchange. Ford coil, $4; or will trade for coupler or $19 for $ 5. Blitzei half K.W. Transformer, Burgess Stewart, 222 Main Street, Huntington, Blitzen 43 plate variable. What have you? Jack new, mounted, $13. R. J. 4 Audion, new bulb, W. Va. Gillette, Purcell, Okla. $12. Claps- Eastham Variable, 43 Plates, $4, new. Never used Audiotron Panel, sells $12.50, $11. FOR EX CHANGE-Dunduplex, Relays, Tape, SLIGHTLY USED 2,000 ohm wireless head Transmitter, Sounders, Combination Set, Motor,. One Multi Audi -Fone, new, with head set com- set with cord for $3. Claudie Law, Kaymoor, plete, $12. Numerous other instruments. Big Aerial Insulators, in exchange for good Receiving W. Va. Set. John Bouman, Reinholds, Pa. Bargains. Cash only. Guaranteed. Second Sets. Presbyterian Church Wireless Department, Don 1909 BARGAINS-Two wireless Receiving FOR SALE -Modern Electrics, June to June Price, $7 each. Write E. M. Sensenich, R.F.D. D. Tullis, Pastor, Newark, Ohio. 1914; Popular Electricity, Dec. 1909 to Nov. 1914; No. 3, Lititz, Pa. $5 Remington Electrician & Mechanic, Feb. 1910 to Jan. 1912; HOLTZER -CABOT phones, inclusive; first five numbers Amateur ISilechanics. MARTIN VIBROPLEX -Wedge and cord, typewriter, $5. White, 557 Franklin Ave., Brook- All first class condition. First $8.00 takes them. $10. Magneto, $1.50. .38 cal. revolver, $6.50. lyn, N.Y. Leon Bryant, Camden, Me. Also other instruments, books and chemicals. DAUGH ERTY visible typewriter ; 4x5 Poco FOR SALE -High Power Binocular; Small Gen- Send for list. Will sell or exchange for Holtzer- Folding Camera, 4 double plate holders, 3 extra erator; water Motor. Other goods. Send for Cabot phones, loose coupler, microscope. See Lenses, carrying case and tripod, 3%x3.5 EXPERIMENTER. Coyd Maffet, Opal, Slide Trom- ¡ lists. A -1 Condition. Arthur Heil, 1848 Fern ad in October Camera, 2 doz. Plates, Small Kodak, Ave., Easton, Pa. Colo. bone in case, Columbia Graphophone Type B. K.T. with 4 Minute attachment and 2 doz. rec- FOR SALE -High class wireless outfit, send- POST PAID -Electro Tuner, $1.25; E. S. 75 Disk Grapho- worth of Mecanno, $1. ords; Ban 'o and case; Columbia ing and receiving. If you are interested in buy- ohm Phone, 35e.; $1.50 phone Tyl e A.K. Two Watches. Two Cycle ing instruments of the best makes very cheap, no Clarke Olney, E. Cleveland, Ohio. Incubators. Want W.reless goods or cash. C. L. home made stuff, write, Elliott Sparling, Ashland, 3,000 meter Sternberg, Box 212, Cherry Valley, N.Y. Wis. FOR SALE -Multi- Audi -Fone, pocket receiving tuner, tunes 3,000 meters. Prac- EXCHANGE -Almost new Martin Vibroplex FOR SALE OR EXCHANGE -Complete pow- tically new, $4. Phone cushions, 50c. Want telegraph key for phonograph parts. H. Lince, erful X -Ray outfit, that will show bones thru hot wire ammeter and commercial key in good Allegan, Mich. .4 inches of pine plank. Address' F. E. Austin, condition. Send stamp for sure reply. Schuyler Box 441, Hanover, N.H. Mass. FIRST CHECK for $32 takes 1914 Thor White, East Northfield, single ligkt model -motorcycle. Have also $8 FOR SALE- Unwound Manhattan No. 3 Mo- FOR SALE-Complete wireless receiving set, motor -dynamo, $3.25; loose coupler, $3.25; pri- tor, $1.50; Variable Condenser, $1 ; "Junior" receives 1,000 miles. Cost $25. Sell for $9. mary loose coupler complete, $1.25; secondary, Tuner, $1; 1,000 ohm Receiver and band, 75e.; Write for particulars. Eugene Whittemore, 23 $1; Smith. Premier typewriter, 2 R.W. trans- 2,000 ohm Set $3; half kilowatt Transformer, Florence St., Roslindale, Mass. former; Model X Conley camera dynamo or $9; Condenser for same, $2.50; Edgewound strip motor casing $1. Dewitt Duffield, Van Wert, for half kilowatt Oscillation Transformer, $1; FOR SALE- Complete half kilowatt sending Ohio. Wireless Telegragh Construction for Amateurs, and large receiving outfit in guaranteed perfect 50e. Willard Kates, Arlington Heights, Ill. working order. Cost, $97. Sell for $38 cash. NEW FLITZEN :4 K.W. Transformer, $10; Outfit connected and assembled in large birch K.W. Transformer $13; SOME Transformer; EXCHANGE-Tubular skates, new, tan shoes, cabinet. All instruments manufactured. Mur- marble base aerial change-over and power size, 5 -6)4, with money, for 'A K.W. transmitting, dock, Turney and Brander apparatus. Gorham switches, °2;< one burnt -out audion. Want four rotary spark. Can't use skates, how much do Cottrell. 1628 Jersey St., Quincy, Ill. sections molded condenser, variable receiving you want? All letters answered. Walter Fd condensers. Richard Preece, Jr., 409 Irving, To- Litke, 361 East 188th St., New York. HAVE GENERAL ELECTRIC Switchboard ledo, Ohic. type A. C. ammeter from 1 to 15 amps. Will Gas En- WANTED- Crystaloi, Murdock Phones, 43 reliable hot wire ammeter. FOR SALE OR EXCHANGE -Small plate Variable, 700' Antenium Wire, Insulators, exchange for good gine Patterns. ,A H P. W. C. -1 H. P. A. C. etc. SALE OR EXCHANGE -Electric Horn, M. S. Andelin, Richfield. Utah. new. Maze offer. H. Bollinger, Sycamore, Ill. $1.50; Steam Engine, $1.85; "Boy Electrician," FOR SALE -E. I. Co. Selenium Cells never FOR SALE- Electric Therapeutic apparatus $3; W' Coil, $1.40. All good as new. Glenn used. Cost, $5. Sell, $4 postpaid. Stromberg ap- Iowa. or willing to exchange for a high frequency Xruwell, Hubbard, Carlson Telo. Transmitters new. 75c. Telo. In- paratus fer a very reasonable difference. Will duction coils, 50c. each. Also some telephone is in perfect condition with WHO HAS high power Winchester or Savage sell say this apparatus carbine to exchange for complete wireless outfit. receivers, Condensers and Ringers. Will all equipments and is the very best apparatus Marconi type tuner, rubber base, 3,000 ohm cheap. F. A. Steinhrook, Brookville, Pa. for all aerial conditions and vibrations for dem- p.m. or any phones, Clapp Eastman variable, detectors, crys- BOAT OWNERS -Mariner's Liquid Compass, onstrations. Kindly call after 7:30 tals of all kinds, 600 feet phosphor bronze aerial time on Sundays. John Ferguson. 364 West $5: Government Charts, New York -Chesapeake New York wire, dozen electrose insulators and other wire- $1.75. Cash or headset. 57th St., Office, 113 West 63rd St., V. C. Poe, Inland Water Route, less equipment. Outfit guaranteed. C. Marsden, 10 Bayley Ave., Yonkers, N.Y. City. 862 Sterling Place. Brooklyn, N.Y. NOTIC I -Want wireless instruments, espe- WILL SELL OR EXCHANGE -What have Have $15 PANEL RECEIVING SET -Hard rubber or cially detectors, coils, receivers, etc. faced panel, Mahogany finish case, 3,000 meters. you? 110 volt '4 horse power generator set drawing instruments; folding kodak; slide Price, motor $10; large switchboard ammeter, also volt- compasses; measuring tapès; Send for further particulars and picture. 3.000 rules; dip needle; $125. Also pair 2,000 ohm, $4. Murdock meter, each $8; Navy type loose coupler, hundred United Profit Sharing Corp'n's certifi- Dan- meters, $6; Americanized Encyclopedia Britan- brown phones, $3. Hollis Ingalls, 7 Holton St., film, En- cates; 75 Curtis Publishing Company's vers. Mass. nica, $10; 3% by 4''% camera, plate or vouchers; old copies Electrician and Mechanic.; close stamp. William Leffler, Tiffin, Ohio. Sights wireless, wireless tele Popular Mechanics: Everyday Mechanics; FOR SALE -Complete of the World. Current Events, and almost 600 2 -55A Rheostats; 1 main LOOK plate variable, $3.50; type O crvs- phone. Bargain -43 in North Dakota. Want anything else? switch 150 A. Many other articles. Write for taloi, $3; omnigraph, $2.25; printing press with addresses wireless articles. all in fine What do you want for your typewriter? Green- particulars. Reuben Scholz, Majestic Theater, type. $3. Also other Minneapolis. Minn. Sheboygan, Wis. condition. Owen Cook, Marinette, Wis. berg, 721 Twelfth Ave., You benefit by mentioning "The Electrical Experimenter" when writing to adve "tisers. ,

64 THE ELECTKICAL EXPERIMENTER December, 1916 WHITE, GRAY AND SPOTTED RABBITS, FOR SALE-Will-sell at sacrifice, 12 -inch spark SALE OR EXCHANGE $1.25 per pair. Also E. I. Loose Coupler, new, coil in case, independent -2 cylinder ignition $2.25. Want Transcontinental interrupter, U. S. field coil, 6 v. 40 amp. battery, small 110 v. fan. or any good long set type, and heavy brass key. G. W. Shull, Want variable distance set. Must be reasonable. No phones. Chambersburg, Pa. condenser, Crystaloi or single cyl- L. Hammond, Badin, N.C. inder, high tension magneto. Ellsworth- Harrison, FIRST $13 remitted takes brand new K.W. R. No. 4, Cortland, N.Y. EXCHANGE-Gray and Davis Starter, Guitar, Magnetic / Tail Lamp. Want coil, typewriter. Shunt Transformer. What have you? FOUR AUDIOTRON bulbs, never used, oscil- Oliver Es- Adolph Schwartz, 1321 Franklin Ave., Bronx, till, Glasgow, Missouri. N.Y.C. lators, $4 each. 15,000 meter undamped coupler, $9. 1 Kilowatt transformer, $9. Paul Flehr, EXCHANGE -4 horse power motorcycle en- FOR Ironton, Ohio. gine for complete receiving set manufactured. SALE-One $11 Omnigraph with two Schwarzburg, 1019 Kentucky sets of five records, $7. Thomas Hicks, 318 West BARGAINS K.W. Telefunken St., Quincy, Ill. 57th St., New York City. -5 transformer FOR SALE-Bardon Rifle Range Telescope, -AM M Varicoupler; Brandes phones; Aerial power, 10,000 Meter Loose Coupler, new, $35 in fine Switch; Lightning Switch; Round Audion; Load- 33 times. Celestial Eyepiece included, ing Coil; potentiometers, power 56 times. Good condition. $20 prepaid condition. $15 takes it. H. Genodette, Kinder - etc. Want Sonora. H. - Rook, 17 Euclid to any address. Sherman E. Matter, Plainfield, hook, N.Y. Ave., Ridgefield Park, N.J. Ill. BARGAIN -First check for $12 takes one of COMPLETE Wireless Station, $27; Brandes- FOR SALE -Four cylinder, nineteen horse- the E. I. Co.'s transcontinental receiving sets, No. Superiors. First good offer takes it. Geo. Ewald, power R. C. H. gasoline automobile engine. 1601. Has universal detector extra. New. Roy 168 Union Hall St., Jamaica, N.Y. Water cooled complete M. Casper, 621 E. Immis St., Salisbury, N.C. with crank and magneto FOR SALE -Brandes Superior single headset base, $25. Two cylinder Maxwell gasoline en- WANTED -Second hand horse power gaso- gine, / $2; fifteen inch double slide tuner, $2; Amco water cooled, complete with carburetor and line engine with carburetor. Must be in good /y K.W. closed core with Bosch Magneto, $40. Both guaranteed first primary variation used class running order. Write. Howard Pfeiffer, Con- 1 month, $10; small coupler, $1. Lee Hodges, condition. Clarence Vaughan, Middletown, N.Y. nerville, ïnd. 3408 Duvall Ave., Baltimore, Md.

Opportunity Exchange 01.1 will probably find Y more opportunities and real bargains t 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 time to scan through these columns. will be the real loser if you don't take the 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 credited advertising agency. all classified advertisements unless placed by an ac- Ten per cent. discount for 6 issues, 20 per cent. discount for 12 accepted. issues from above rate. Objectionable or misleading advertisements not Advertisements for the January issue should reach us not later than November 25. OVER 70,000 PEOPLE READ THIS JOURNAL EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York, N.Y.

BOOKS IDEAS WANTED-Manufacturers are writ- TRANSFORMERS -Make your own trans- ing for patents procured through me. Three formers according to illustrated directions in the HAVE YOU SEEN A COPY ? -Amateur Pho- books with lists of hundreds of inventions wanted third edition of `How to Make Low -Pressure tographer's Weekly, $1.50 per year; weekly prize sent free. I help you market your invention., Transformers." Sold to amateurs all over the competitions; criticisms; print exchange; illus- Advice free. R. B. Owen, 130 Owen Bldg., world. Very valuable book for experimenters. trated; many features. Three months' subscrip- Washington, D.C. Price, 40c., postpaid. Remit to Prof. F. E. tion, 40c. Amateur Photographer's Weekly, 915 Austin, Box 441, Hanover, N.H. Schofield Bldg., Cleveland, Ohio. PATENTS BRING RICHES -Protect your invention. Attorney's fee payable when patent al- EXPERIMENTAL WORK and apparatus made BOOKS -Scientific and wireless supplied. Let lowed. Plain advice and `Patent Facts" free. to order. Have small lathe, take anything in us know what you want and we will quote you. Trademarks registered. Jaynes & Jaynes, 501 exchange, or give lowest price. J. F. Young, Experimenter Pub. Co., 233 Fulton St., New, Kellogg, Washington, D.C. 1938 Federal York City. St., Philadelphia. Pa. PATENTS SECURED OR FEE RETURNED SECOND HAND telephones with generators, A BINDER FOR eTHE -Send sketch or model for free search and re- $5; Telephones PERIMENTER will p a copies for all port. less receivers, $2; Automatic your Latest complete patent book free. George switches, six coils each, 60c. Coils three for time. Price 50c. Postage on 3 lbs. is extra. P. Kimmel, 254 Barrister Bldg., Washington, 25c. Send for one to -day. Experimenter Pub. Co., D.C. Will trade for radio apparatus. Radio 233 Fulton St., New York City. apparatus for trade. Garden City Radio Club, PATENTS -Without advance attorney's fees. 901 Fourth, Garden City, Kansas. Not due until patent allowed. Send sketch for HELP WANTED free report. Books free. Frank Fuller, Wash- DO YOU WANT to experiment with high ten- ington, D.C. sion electricity but haven't got the price? If MEN AND WOMEN, 18 or over, wanted for so you are the fellow I want. I furnish all ma- U. S. Government life jobs. $75.00 month. JOHN M. McLACHLEN, attorney-at- law -Pat- terial. Must come here. Also good chance to Steady work. Short hours. Rapid advancement. ent causes. Union Trust Bldg., Washington, D.C. learn Motion Picture Business. A. R. Holder, "Pull" unnecessary. Common education suffi- HOW TO PROTECT AND SELL UNPAT- No. St. Paul, Minn. cient. Write immediately for free list of posi- ENTED INVENTIONS -Safe, Sure Method. CLOSING OUT STOCK of 2 Filament Super- tions now easily obtainable. Franklin Institute, Saves you $$$$$. Write Inventors' Service Co., sensitive Trons, $3.70 each, 3 for $10. Guaran- Department R -27, Rochester, N.Y. Natick, Mass. teed. Get our line up on all radio goods. Mid - West Wireless Mfg. & Supply Co., Mattoon, MISCELLANEOUS PHOTOGRAPHY Illinois. PHOTOGRAPHY WITHOUT CAMERA SAVE MONEY on your wireless purchases. HERB DOCTOR RECIPE BOOK contains - Authorized agent for Mignon, Multi -Audi -Fone, over 250 recipes and Novel social pastime, using photo paper invisibly herb secrets. Teaches how prepared with interesting and artistic pictures. "Radio," Clapp -Eastham, Brandes, De Forest, to make medicines from herbs, roots and barks. Thordarson and other leading makes of standard Send 10c. coin. Samples prepared for 25 pictures with directions, in Address H. J. Kunow, 2246 10c. Wedge Mfg. Company. "Km," Bingham- radio apparatus. Write for prices on the in- N. Tripp Avenue, Chicago, Ill. ton, N.Y. struments you want. Expert installation advice. STAMPS -75 all different, free. Postage, 2c. THIS MONTH'S SPECIAL; Pair mounting clips Mention paper. Quaker Stamp Co., Toledo, Ohio. MARCONI-We have a limited number of and special hook -ups FREE with every order for pictures of Guglielmo Marconi that are done tested Oscilaudion or Electron Audio QUESTIONS on engineering answered at 25c. in sepia on fine India paper. Fine for decorat- bulbs at each. Engineering difficulties straightened out- ing $4.50 each. Careful attention, immediate ship- your wireless room. Ten cents each, post- ments. Arthur B. Church, 131 Hyland Ave., tell ate your troubles. A. Sticht, 612 Grand St., paid. Experimenter Publishing Co., 233 Fulton Troy, N.Y. St., New York. Ames. Iowa. CHRISTMAS TREE OUTFITS. 24 porcelain MAKE YOUR VARIABLE into á wavemeter. sockets and cut out block. All wiring green silk WIRELESS Wavemeter inductance, $1. Send 3c. for but= insulated. Complete with plug attachment. $5.85 letin of bargain now. Keco Electric, Box 164, per set. 2 sets $11. Wm. Paul, 126 Marion St., IF YOU ARE planning a transformer let us Kinderhook, N.Y. Brooklyn, N.Y. show you how we can save you money on the NEW GALENA SENSITIVE MAINTAINER secondary windings. Made right and guaran- -The latest and best for wireless use; galena PATENT ATTORNEYS teed. Tubes wound for loose couplers. State lasts for years using this new detector. Send your wants plainly. Eureka Secondary Co., 6937 10c. for blueprint, description and prices. Gerald AMERICAN AND FOREIGN PATENTS S. May Street, Chicago, Ill. Fenstermaker, Lancaster, Pa. OBTAINED. Before selecting an attorney TELEGRAPHY-Morse and wireless, also NEW INSTRUMENT better than rotary or write for our solid, instructive advice; join the Station Agency taught. Graduates assisted. iuenched gaps for coils. Increase gauge of ranks of happy inventors. Correspondence office, Cheap expense, easily learned. Largest school, spark coils 100%. Blueprints and hook -up, 25c. 125 East 23rd Street, New York City. F. V. established 42 years. Correspondence courses H. Winters, Reg. Patent Lawyer. New York City also. Catalog Free. Dodge's Institute, Lone A. Carlson, 184 Green St., Cambridge, Mass. and Washington, D.C. St., Valparaiso, Ind. WIRELESS OUTFITS make substantial PATENTS- Personal attention to all inquiries. STRANDED TUNER WIRE for receiving arc Christmas gifts. Give your boy one. We have No printed literature. No lists of "Inventions and long distance -10 copper enamel wires cov- them complete at $5.75. Wm. Paul, 126 Marion Wanted" -such being unauthorized by the Pat- ered with silk at lc. per yard, 20 wires 2c., state St., Brooklyn. N.Y. ent Office. Fees reasonable, consistent with best whether No. 36 or No. 38 enamel wire is de- LOOSE COUPLERS, $4.50; Detectors. $1.25; results obtainable. Electrical and Mechanical sired, discount on / and 1 pound lots; special Receivers, $3.50; Condensers, 50c. up. Send for Expert. J. Edward Bangs, Suite 409, Barrister sizes to order. No stamps. J. H. Claus, Hulme- pamphlet. \\'m. Paul, 126 Marion St., Brooklyn, Bldg., Washington, D.C. ville, Pa. N.Y. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. MURDOCK Standard double pole, real wire- If long distance receiving records less receivers, with genuine copper are to be considered final in judg- wire windings, equal in quality of No.55 ing receivers, these 'phones must materials and operating efficiency be rz.ted exceptionally high. We to any 'phones obtainable any - can show evidence of clear recep- where at double the prices.. The tion with these 'phones across the purchase of these 'phones means continent and oversea records of an investment in satisfaction and 6000 miles and more. a real saving in money.

3000 OHM COMPLETE DOUBLE SET 500

Buy Them Because They Are The Best that you can obtain for every -day, sensitive, de- FOURTEEN DAYS' TRIAL pendable service. Disregard, if you can, the fact you are dissatisfied in any way, send 'em back that they are remarkably low in price. Forget, and get your money. if you please, that the illustration shows a good - A trial in YOUR station will show you why looking, high -grade equipment. Ignore, if you many commercial operators are using these 'phones wish, the sterling reputation of the manufacturers. in preference to the receivers supplied by their are in daily use in the radio on the basis of what they will employers: why they Buy these 'phones laboratories of several of the leading colleges of do for YOU in YOUR station. ORDER A SET the country: and why thousands of amateurs NOW, and if, after regard them as the best value in the world. ORDER YOUR SET NOW At this, the naturally busy season of the year, we wish to call attention to the prompt service which is a prominent part of the MURDOCK policy. You may be sure that your order for any of our apparatus will receive our careful and immediate action. Our Catalog No. 15 -- showing 48 pages of really good apparatus --is FREE. Send for your copy today. WM. J. MURDOCK CO. 55 Carter Street, Chelsea, Mass. 221 Second Street Sark F r a n c i s c o

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. ll í

Succeed Through Electricily This interesting story shows you the way to greater success in the Field. This is the Electrical age. Electrical Electricity now controls more trades, directs more men, offers more opportunities than any other power that man has yet discovered. Through exact knowledge of Electricity you will advance in salary and position. 1

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`/1-% ,. I e AV 3 I°g N.t61 it,-7! yi AIRR[IAtiS -- PAYABLE Ia'.' ilAU[Ix! N.R4xlxi WIPoNG A.C. . I Amo0t8N l . W.a[ssl 1 ulfiíxll7 l.pyx',WpS tuauTlRt t moms oYÑÁYOS DISmAII RtIt11NAtl! ' LÎlnx tI1RRINISI Nailed. 1 MtItüAS OioxS SKT[YS axWCÎ BRnIN i IIWAa SIORACI ;(OI/IAf[AS t,n,¡,IxIS'--î/RxAIOAI 11fANAfOAT aGNÌ'MI5 . WqptNG ;riN4 muti h`Mi; -- ÈIJS 'ARI ÌNOO l' t.iJ! o© r4-77-ilit] l.á: A Month Shipped to You FREE YOUR Send no money. Examine the books first. Decide for yourself that they are the most FREE complete library of Electricity ever published and that you cannot afford to be without COUPON them. Every book is complete in itself, but the complete set is the best bargain. The last off the press. Eight numbers now ready. Theo. Audel 8 Co. Accept this unusual offer now -to -day. Each 72 Fifth Avenue, N,Y. N page-every illustration will convince you of Please send me for FREE exam- See ination Hawkins Electrical Guides the big value we are offering. the once If you A FEW OF THE SUBJECTS (Price $1.00 each). Ship at books first, then decide. de- Maggnnetism- Induction -Experiments - Dynamos prepaid the TEN numbers. If sat- -Silectric Machinery- Motors -Armatures -Arm- cide to keep them you can make ature Windings-Installing of Dynamos-Electri- isfactory I agree to send you $1.00 each settlement at only $1.00 monthly c d Instrument Testing-Practical Management until paid. of Dynamos and Motors- Distribution Systems - month until paid for. Wiring- Wiring Diagrams -Sign Flashers -Stor- age Batteries -Principles of Alternating Currents and Alternators-Alternating Current Motors - Signature Tran sformers- Converters -Rectifiers- Alternat- Theo. Audel & Co. ing Current Systems -Circuit Breakers- Measur- Occupation ing Instruments-Switch Boards-W firing -Power 72 Fifth Avenue Stations - Installing - Telephone - Telegraph - Business Address Wireless-- Relis- Lighting-Railways. Also many NEW YORK Modern Practical Applications of Electricity and Residence Ready Reference Index of the 10 numbers. Reference Dec. E.E. 114411.111111111111111 i