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1919 January, ELECTRICAL EXPERIMENTER 601 Bigger Pay for YOU '*See them You Can Now Knov\r first-pay afterwards * ELECTRICITY As Experts Know It Small When we observe the ever-increasing applications and usages of Monthly electricity, we wonder if all the present openings and the newly created positions in Payment the electrical world can ever be filled.

if you Ve The ending of the war lends a new and mighty impetus to the electrical end satis- of American industries. Salaries are soaring. There is practically no Hmit to the earning power of the man fied who educates himself in the finer points of electrical work.

Actual working facts With the advent of the new Library of Practical Electricity by Terrell Croft, a new era is marked in the production of self educational electrical literature. This library satisfies a demand never heretofore met—the demand for a home study course which would bring out in detail the actual workmg facts. This great undertaking has been accomplished. It IS a seven-year task completed. No previous electrical training necessary Three thousand I pages, with twenty-one hundred of the clearest illustrations ever put into book form. Each of the eight volumes is indexed so that everything you want to know about electricity is at the finger's end. And when you hnd what you want, there is not merely a short question and a short answer. You are told everything you want to know. The explanation is clear to you, regardless of whether you have had a previous knowledge of electricitv or not. -' Know electricity as the highest paid engineers know it When you are studying the Croft Library of Practical Electricity, you are studying electricity as experts know it. You are acquaint- ing yourself with the methods employed by the highest paid electrical workers and engineers 8 Vols. in America. This Library of eight volumes Flexible sent binding to you FREE for] 10 days' trial So Pocket positive are we that you will be pleased with size Croft Library the of Practical Electricity that we offer to send the entire ten volumes for ten days' free use AU you need do In order to have the books ^ 3000 sent, charges prepaid. Q Is to flu out the attached coupon pages and return to us. Keep the books ten full days. Then If you are not satisfied return them at our expense. If On the other 2100 hand, if you find that they will help you, as they are vo helping thou- illustrations sands of others, send us the small ^ McGraw-Hill Bum of $2 per month for eight Book Co., Inc. McGraw-Hill months. 239 W. 39th St A letter that Book Company, Inc- NEW YORK 239^oi> Westv»e»i 39thoBin atreet,Street, Newl\ew York, N. Y. means something cROFrls^vFwV'.BS.o'if'^t'.i^ "p'"= myseif about ^^^ UBRARY OF PRACTICAL ELECTRIC- Oentlemen X . "'^.r-A? , haveu never tO every man m ' seen and do not believe there was ACT Please send me ttie Li- P''.""*'' .'"•'« English language, a brary of Practical Elec- L • ^^!j: more com- tricity (ahlpplng charges A^ Preheniuve .et of books. It is a library pre- America who is that is just as pai{J). .for 10 days' free eram- ""vice as to the expert, laation. because it is NOW If satisfactory, I will all pracUce interested in send $2- In ten days and $2 per Respectfully, month, until $16 has been paid. If not wanted I -'H iir"-- rn fin m n electricity ^^^ " PEIFER. shipping ru- , n . c... ^ Chief, Doplan SUk Corporation, Hazleton Pa

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Vol. VI Whole No. 69 JANUARY, 1919 No. 9

SMOKE BARRAGE SAVES ESCAPING 'PLANE Front Cover POPULAR ASTRONOMY—GIANT JUPITER AND HIS NINE From a painting by George Wall. MOONS By Isabel M. Lewis 620 AMERICAN DESTROYERS THROW DEPTH "BOMB BARRAGE" 605 NIKOLA TESLA TO WRITE "MY INVENTIONS" FOR "ELEC- SOLAR ENGINE USES SUN'S ENERGY 607 TRICAL EXPERIMENTER" READERS 622 ELECTRIC DEATH TRAPS IN HUN'S RETREAT NEW PROPOSED WIRELESS BILL AND DISCUSSION 624 Bv H. Winfield Secor 608 IN WITH SUR- EXPERIMENTAL PHYSICS — ELECTRICAL CONDUCTION SUBMARINES PEACE TIME—WHAT TO' DO THRU GASES By John Furia, A.B., M.A. 626 RENDERED U-BOATS 610 J. TELEPHONING FROM MOVING TRAINS 610 MY RADIO "STATIC ELIMINATOR" By Dr. Nikola Tesla 627 SMOKE BARRAGE SAVES ESCAPING 'PLANE 612 RADIOTELEPHONE GUIDED U. S. FLYERS MANY MILES "THE LONG DASH"—A WIRELESS GUN SHOW 613 AWAY 629 AN ALL-ELECTRIC HOT AIR BALLOON 614 THE MANUFACTURE OF VACUUM DETECTORS. THE CITY OF SPLENDID NIGHT By Amos Stote 615 Bv O. B. Moorehead. 630 "ODD PHOTO" PRIZE CONTEST—A GALAXY OF WORLD- A VERTICAL CABINET TYPE COUPLER.. By Joseph H. Kraus, Jr. 631 BEATERS 616 BUILDING A 3-INCH SPARK STATIC MACHINE. ELECTRICAL DENTAL AUTO FOR UPTON SOLDIERS 617 By Dr. E. Bade 633 NEW BRITISH 'PLANE COASTS 20 MILES TO SAFETY 617 A 2S-INCH MODEL GYRO-ELECTRIC DESTROY'^ER—HOW I NEW FLASHLIGHT CUTS OFF AFTER ONE MINUTE 618 BUILT IT 6i4 FOOLING THE DRAFT BOARD?—IT CANT BE DONE 618 EXPERIMENTS IN RADIO-ACTIVITY—PART I—IONIZATION. 636 WINTERTIME USES FOR ELECTRIC FANS.. By Pauline Ginsberg 619 EXPERIMENTAL MECHANICS—LESSON IX. By Samuel D, Cohen 63J

ctirk mu€

^^^iERE are many different ways of produc- tions of a diafram are very great and while it is pos- 1 'S57i I i„g music, and as our culture advances the sible to obtain a single pure note, it is a different mat- desire for better and still better music ter where several pure notes in different octaves are becomes a craving of civilization. From to be reproduced simultaneously. the ancient tom-tom to a Stradivarius violin is a long cry, and the chances are that A way out is suggested by the writer by pressing into as our musical tastes become more refined, service the thermo-telephone which employs no diafram still better instruments will become necessary and highly at all, but uses a very fine platinum wire of microscopic desirable. cross-section. This platinum wire, heating and cooling in unison with the electrical vibrations, imprest upon There are few instruments giving a more mellow and it imparts these impulses to the surrounding air. With a more "human" sound and quality of tone than a fine this device very pure electrical music can be obtained. violin, but we have no hesitancy in saying that it should be possible to obtain still better results by electrical There should be of course many other ways to actu- means. Tlie field of purely electrical music has hardly ally produce pure electrical music, and here is a wonder- been touched. Some years ago an American inventor ful opporturtity for experimenters and inventors. To the produced the Telharmonium. This was one of the writer's mind, it seems not at all impossible that we earliest and best attempts at pure electrical music. The should take a metallic wire stretched taut and by im- Cahill Telharmonium was invented by Dr. Thaddeus pressing an electric current upon it, vary its heating and and he used alternating current generators, each of a cooling effects so as to produce pure sounds in a suitable certain frequency; if a telephone receiver were connected receiver such as a thermo-telephone. in the circuit, the latter would give forth a certain very pure note. By using a switchboard arranged in Dr. de Forest has shown us that beautiful music can the form of an organ keyboard, wonderful musical be produced in a vacuum tube. Paradoxical as it seems, effects were produced. this nevertheless is a fact. There must be many other ways of producing vibrations in a vacuum tube which Another more recent attempt was the pure electrical can be translated into an electrical current, thus pro- music discovered thru researches of Dr. Lee de ducing music. Forest. He used his audion bulbs in connection with a telephone receiver, and obtained beautiful fiute-Iike tones There are also certain ways of making electromagnets of the greatest purity. The two devices just described produce music— this without the adjimct of telephone necessitated the use of a telephone receiver to translate receivers,—by vibrating their entire structure. Many the electrical impulses into sonorous vibrations, and this other means will undoubtedly suggest themselves to our is a great disadvantage, for it ties us to a thin diafram, students and scientists. which in itself cannot produce the very purest tones obtainable. As one can readily understand, the limita- H. Gernsback. I

been Included. ALL accepted contribu- 'ELECTRICAL EXPERIMENTER In publlsht on the 15th of each month it 233 tions cannot be returned unless full postaae has rt^ paid for novel experiments: good Fulton Street, New York- There are 12 numbers per year. Subscription pric« Is $2.00 a tions are paid for on publication. A special rate is are highly desirable. year In U. 8. and pcsses'lnns Canada and forelfm t-ountrlea. 12.50 a year. C. S. coin as photographs accompanvlng them Monthly. Entered as second-class matter at the well a« C. 8. stamps accepted (no foreign coins or atampB). Single copies. 20 cents each. ELECTRICAL EXPERIMENTER. under Act of Conifress of March 3, 1879, Title registered U, 8. A sample copy will be ^-iUt gratis on request. Checks and money orders should l)e drawn New York Post Office E. P. Co., Inc., New York. The Contents of this to order o( EXPERIMENTER PCBI.ISHINO CO., INC. U you chanee your address Patent Offlce. Copyright. 1918, by copyrighted must not be reproduced without giving full credit to the notify tia pTomptlv, In order tbat copies are not miscarried or lost, A Bf0*n wrapper In- magalne are and dkatel raplratlon. No copl« sent after expiration. publication.

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602 January. 1919 ELECTRICAL EXPERIMENTER 603

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604 ELECTRICAL EXPERIMENTER January, 1919

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Vol. VI. Whole No. 69 JANUARY, 1919 Number 9 American Destroyers Throw ''Depth

Bomb Barrage" '

AN American destroyer, with her depth time. The arrangement of the American square inch for every foot of head or f\ bombs ready to be discharged, is a destroyer's depth bomb armament that ilepfii. Thus for 1 foot depth the hydro- / \ dangerous craft. Running without struck terror into the heart of German static pressure acting on the shell, and also •^ -Rights in the darkness she is a men- submarine commanders is shown in the ac- the diafram, would be .433 lb. for every ace not only to the enemy but to companying illustration. These depth sq. in. of surface area. For a depth of herself and other ships should a collision charges are dangerous to a submarine, even 20 ft. the water-pressure per sq. in. would if they are 500 to 1200 feet away from the be 8.6 lb.; for 50 ft. depth, 21.6 lb., and

ropyrlBht, 1918. by E. P. Co. U. S. Destroyers Have Greatly Profited By Actual War Experience, for They Became So Proficient In the Use of the "Depth Bomb"— Wonderful New Weapon in Itself—That They Could Set Up a Veritable "Sub-aqueou s Barrage." Also They Can "Shoot" Depth Bombs for a Distance of One-half Mile or More. Unlike Shells They Do Not Ricochet or Slip, But Penetrate the Water to a Certain Depth and Then Explode.

for 100 ft. depth, lb. The bombs are now released from every point where the subaqueous explosion oc- 43.3 per sq. in. Hence it is clear how it becomes possible to "set" quarter of the destroyer. Two can be curs. the diafram of the detonating device, dropt from the bridge by pressure of a The detail view herewith of one of these whether electrical or mechanical, to trip button; "Y guns," amidships, with two principle depth bombs shows clearly the off the latter at any desired depth. The barrels, can to port or star- steel throw bombs upon which they operate. The tank farther the contact pin, or trip finger, is board; astern there are two long lines of container is a simple affair, fitted with a set back or away from the diafram, the bombs running on miniature railway tracks, sensitive water-pressure diafram. The greater the water-pressure or depth re- so a complete barrage may be fired at any pressure of the water increases .433 lb. per quired to press it in that far.

605 606 ELECTRICAL EXPERIMENTER January. 1919

AND NOW THE ELECTRICIAN- sitting room, turning on the switch, and in attired young lady, in over-alls. Taken ETTE! anticipation of the warmth that you are to back with this surprise, you ask her what We have conductorettes, female bartend- get, you find the electric stove is as cold as she desires. "Oh, Sir," says she, "I am the ers, police women, elevator operators, usher- a chunk of ice. The heat of your indigna- electrician! You sent a call for me, and I ettes and farmerettes, but this is the first tions warms you thoroly, and you make am here to repair your heater." Her in- instance of its kind t e n t i o n is very where we are having agreeable to you, an electricianette. and with military Mrs. Ada B. Vail precision she brush- of the Atlantic City es past you, takes off Electric Company, the top of the heat- Atlantic City, New er, yanks out the Jersey, has complete heating elements, charge of an instal- mutters a monosyl- lation of sixty-five lable that sounds electric ranges in like "burnt out," in- one apartment house serts a new unit, at- located at the above taches another fuse, address. She is re- turns the switch, sponsible for the and the job is fin- proper maintenance ished. It has taken and operation of the her exactly ten min- entire equipment of utes, and the most these stoves and incredible part of handles her position it, when you ask her capably. Beside, she tlie charges, and re- takes care of some ceive a reply, "Oh, thirty-five odd elec- that is all right, sir, tric stoves thru- I am paid by the out the city. In all, firm that owns the she super\'ises one building." She goes hundred of these in- out closing the door tricate electrical de- very gently, and vices. without even look- Her entire tool ing for a tip. kit can be summed Cheer up, fellows, up into a testing it will be a great old lamp, screw driver world after the fair and two pair of pli- sex take our jobs. ers, one large and We will have noth- one small. Compare ing to worry about this neat and com- except washing the pact equipment that I'holo Courtesy Edison Kleculc liliuumfttlBX Co. of Boiton dishes and scrub- bing the floor. most certainly re- Yes, the "Electrlclanettes" Are Herel The Present Photo Shows Them Hard at Work flects the character- at One of the Dynamo Switch-Boards of the Boston Edison Company istics of a woman as tool chest one grand dive for the telephone. After WORLD RADIO its owner, with the modest (?) SYSTEM URGED stood there for about a half hour of the male species of electrician and the you have FOR SOCIALISTS. waiting for the carrying of a large assortment of unneces- with your teeth chattering, boy in the hall below to answer Active steps are being sarv junk, approximating one-half ton in telephone taken by the In- finally rewarded for your ternational Socialist weight, and when he finds that the job will your call, you are movement to estab- patience being allowed the honor to speak lish a private system of wireless thruout require a screw driver one-sixteenth of an by with the janitor. After you have told him the world. Five installations are def- inch smaller in size, we would be asking too now one what you thought of him and his entire initely projected. Stations will be immedi- much if we should expect him to use family, back to his great, great, great grand- ately set up in England, France, Belgium of the next size. Instead he takes an after- sweetly answers with a roar and ultimately in noon's vacation on your time, going to the father, he very other countries, including like Kaiser; and tells you that your need America. movies or to Coney Island, or Kalamazoo the will be attended to. Three of the new stations will link up as far as we know, and by the length of Within a few seconds you hear a short with the German and possibly the Russiair time that he consumes to get this tool. Can you imagine upon arising from your stacatto knock upon the door, and upon Socialist wireless. They will be used to warm bed on a cold Winter morning, mak- opening it you are almost stricken speechless connect Socialist organs in various coun- the appearance of a very neat and chicly tries. ing a quick dash to the electric stove in the by

where and water forces needed to turn the scale In collision there is no danger of the in the air. Cases have been known it thing which, shock exploding the bomb, but some might a submarine's plates have been dented in against her, but was the distance of working the other side, added speed be thrown into the water and explode when and the seams started at a from the the Kaiser's hopes and the proper depth. nearly one-half mile. The concussive wave to downfall of at _ transmitted thru the water is exceedingly his empire. The fears and the despairs And this is not all of the Depth Bombs reason, water is which the submarines could not create in story, either. Did you ever hear of the powerful because, for one the minds of the Allies they did create in depth bomb "gun"? It shoots depth bombs practically incompressible. mutinies in those of the had been ordered accurately for a distance of half a mile or Remembering that stores of men who more. The merchant ships that dodged the the German naval ports first gave clear to commit the atrocious crimes by which U-boats were equipt with such guns, which intimations that Germany's military machine the world was shocked. operate with comprest air, similar to the was breaking down, it is not surprising They did what they were told to do, but well-known torpedo tube. The illustration that the revolutionary movement first the task proved too much for even their should have assumed serious form among shows how the depth bomb gun is sighted docility, and they rebelled against it at according to the current to drop the bomb just at the point where the sailors. And last, not, however, so far as any evidence the reports, the terrible hardships and the it will complete its trajectory thru yet presented has shown, because of indig- ghastly number of fatalities among the water and explode near the enemy sub- nation against the orders received, but is sneak- U-boat crews are what started the final marine, which has submerged and because the execution of those orders so fatal break in discipline and morale. ing off, or trying to. often meant for them the fate of drown- Imagine also the effect of a subaqueous It can be said, therefore, with some ap- ing rats. Too many of the U-boats that barrage on the enemy subsea fighters. Talk proximation to truth, that not only did did return, the trans- unrestricted undersea warfare hasten and went out not and mystery about land barrage fire I The water of their fate was intolerable to the sur- mits the noise and vibrations from the ex- make certain the defeat of Germany by ploding depth bomb many times better than bringing into the war the American land

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January. 1919 ELECTRICAL EXPERIMENTER 607

Solar Engine Uses Sun's Energy

Texas being illustrated herewith. The heat thousand degrees Centigrade is the the smaller amount of increase (7 degrees) of the sun's rays strikes a large number SIXcomputed temperature of the sun. Its would probably suffice for that. of mirrors, which reflect the heat to spe- Hght giving power is equal to 27,000,- These facts are very interesting from a cial boilers. These produce steam to run 000,000 candlepower, a quarter of a technical point of view, indeed. The prac- an engine, the latter operating an electric mile away. Scientists tell us that aspect of solar energy lies at present tical dynamo. The current thus produced was only the 2,73S-millionth part of the total in the hands of those who are endeavoring capable of operating an electric motor pump energy radiated from the sun reaches our to perfect a solar motor—i.e., an engine or which piimped water to a height of 60 feet earth, but if this were ever caused to stop electric generating device which, when the above the ground. for any reason our planet would turn into a sun's rays strike it, will develop steam to to Tacony, dead, frigid ball of rock ; the present aver- operate a steam engine, or electricity Mr. Shuman had running at age annual temperature of 13° C, would charge electric accumulators or storage bat- Pa., a practical plant of this type, which change, without the heat of the sun, to teries. Those interested in this branch of developed about 3^ horsepower by using 73° C, of frost, it is calculated. science will find of great interest several 1,200 square feet of sunshine that was al- box. Experiments show that the power of the articles which have appeared in back num- lowed to fall on a fixt horizontal water fitted with a glass top and a atmosphere to trap heat is largely due to bers of this journal.* This box was black pipes were the water vapor that it contains. It is also Considering later developments of a prac- series of parallel horizontal pipes, con- due to some extent, to the carbon dioxid gas tical nature in the line of solar engines and immersed in the water. These square feet of that is one of its minor constituents, points boilers, we may take up the work of Mr. taining ether, exposed 900 water out Prof. Garrett P. Serviss. Carbon Shuman, of Philadelphia, Pa., who later surface to the solar radiation. The carried the heat to dioxid is a remarkable heat retainer, but collaborated with a Mr. Boys, of England. also became heated and realizing a there is only a very small quantity of They were able in their final the underside of the pipes, thus boiled and its it in the air compared with the vast developments to operate a 100 greater efficiency. The ether cylin- bulk of the atmosphere. It only horsepower engine by means "steam" drove a small vertical, single past amounts to about 3/100 of 1 per cent. of solar energy. This plant der engine. The exhaust ether vapor the liquid But there is this significant fact about was built at Meadi on the Nile, into an air surface condenser and this pumped back into the • it, viz., that its amount is variable, to Egypt. Prior to this excellent ether from was a slight degree at the present time, work, however, we may con- tubes of the sun boiler. It was found that on while there is evidence from past ge- sider briefly the early solar this plant worked well even with snow from the ological history that once it was vast- engines developed and tried out the ground, which is explainable the atmosphere ly more abundant than it is now. at Philadelphia, Pa., by Frank fact that the permeability of than Now, how much carbon dioxid Shuman, upon which work he is about 20 per cent, greater in winter must the air gain in order that a per- started in 1906. One of these in summer. ceptible effect the temperature solar engine plants installed in on may Further tests and refinements to the ? •The Utilization of the Sun's En- be produced Arrhenius answers this plant by Mr. Shuman resulted in ergy Secor, March, 1916, Tacony question for us. He says that if all —by H. W. issue; pa^e 605. 1911 in an engine and boiler which showed the carbon dioxid now in the air were Electricity Direct from Sunlight considerable strides forward in their design, removed, the average temperature The photo-electric cell. September, the ratio of 24s square feet of sunshine per would fall nearly 38 degrees Fahren- 1916, issue; page 316. Volcano-Electnc Plant in Italy one brake horscpon'cr having been attained. heit. On the other hand, if the pres- Develops 15,000 H.P., March, 1917, ent amount were doubled the temper- issue; page 789, It may be mentioned here that the pipes ature would const i tuting rise more the sun boil- than 7 de- ers have in-

grees, and if , ; 1 variably it were quad- been black- rupled the * L: e n e d. For rise would L'-^M* low temper- amount to atures lamp- nearly lAyi b 1 a ck has degrees been used as which would m^._ the absorber, be far more m m but w here than enouffh high temper- to banish all atures were r the glacial e q u i red suffer- platinum ing that we black was Photos \iy International Feature Service. had to en- (P) used. Here We See the Sixty Foot Stream of Water, Discharging. The Electric Power to Pump This Stream r e ( ontinued du last of Water is All Furnished By the Mirrors Which Gather and Reflect th e Sun's Rays Onto Special C winter. Even Boilers. on page 672) : — ;

608 ELECTRICAL EXPERIMENTER January. 1919 Electric Death Traps in Hun's Retreat

By H. WINFIELD SECOR

you have any doubt that the Teuton one of the bombs, the first spark would In Fig. 7 there is shown the famous Ger- with death- man "watch trick." This trick used to be IFis possest of a cunning mind, then you cause the bomb to explode have but to read the reports that have dealing violence. The bomb in this case is pulled quite often at various points along come back to us every now and then detonated by an electric fuse or spark cir- the battle-line until the Allied troops got from various reliable sources on the cuit, actuated by a radio coherer and relay, so skittish of all such devices that they battle-fields of Europe, where the Allied or other similar radio receptor apparatus. would not touch anything with their hands, troops have always had to contend with "Say, Hen," sang out a jolly faced Dough- but would poke it witli a stick, which in- multifarious and indescribable forms of boy to one of his "buddies," as they sat variably caused one of these death-dealing deadly and inhuman offensive schemes, such about a table enjoying the mid-day meal traps to explode harmlessly. In the watch as liquid fire and gas, which horribly mu- of "Boston baked" and canned sardines a la trick, a favorite setting was in a trench tilates and disfigures its victims in thou- Rhine in an old French chateau, "there's a or dug-out from which the Teutons had sands of cases. The Allies were never sure telephone on the wall, why don't you call up been forced to retire, and when the Allied of what they might expect when they ad- your best girl," and full of Yankee play soldiers had taken the trench, one of them vanced on enemy territory. The Huns re- spirit the Doughboy arose. But something would probably be surprised to see a per- sorted to eveo' possible underhand scheme seemed to tell him not to touch the tele- fectly good watch hanging on a nail or their wily brains could think of in a des- phone instrument, and it was well that he stick projecting from the trench wall and merrily. perate effort to spread terror among the did not ; for one of the party, who had been ticking away Now who would Allied soldiers, and some of the despicable cautioned by the intelligence officers to be refuse to take such a watch? But many a "traps" they have used, not to mention hun- extremely careful of touching anything in brave soldier has undoubtedly lost his life dreds of others which we have not the space the captured territory until it had been care- by thinking just that way, and the moment here to describe, are illustrated herewith. fully examined ascertained that the tele- the watch was removed from the nail or projection it hung, this Fig. 1 shows how the Germans often phone instrument contained several pounds other from which mined the town pump, or any other pumps of explosive which was connected up with act caused a high explosive trap to detonate. on which they could operate, so that when a an electrical igniter attached to the switch- And the churches—what haven't the thirsty AUied soldier endeavored to draw hook, so that as soon as the receiver was Teutonic sons of the mailed fist done to some water, he would be instantly killed by lifted from the hook, the explosive would these ! One case which happened in Bel- a charge of explosive set off by an electric gium comes to mind where a number of contact and battery inside the pump, the Allied soldiers were endeavoring to hold in town. The priest had fuse circuit being closed on the first down- DON'T MISS THESE ARTICLES church a captured handle. Of no sooner started to ascend the steps of ward stroke of the pump IN FEBRUARY "E. E." course, hundreds of mechanical traps were I the altar, when a terrific explosion oc- ''Afy Inventions"—No. 1 of a series B used, as well as electrical ones. The elec- g curred, which demolished the alter and especially written for the Electrical seriously wounded the preacher. This trap tric trap which has been extensively used H J Experimenter by Dr. Nikola Tesla electric contact spring arranged in these operations is a simple affair, and m ^ utilized an comprises nothing more than a small dry himself. B under the step, the riser of one of the ''Cold Light!—What it is and is per- or other batterj', together with a pair of m steps being cut away so that when a Rusk, B.Sc. arranged to be closed by m not," by Rogers D. H son's weight rested on the tread, it would electric contacts York"— won- the movement of some piece of furniture, "Subways of New A J force it Aowa a slight distance, closing a derfully complete panorama of the detonated the bomb. See et cetera, a.~.d a piece of fine fuse wire B m contact which underground, surface and elevated s Fig. 8. which is placed in the explosive. When the . B systems. An interesting and instruc- heinous and cnmmal circuit is closed, the fine piece of wire m One of the most M tive article. B death-dealing devices ever planted by the meits, and the heat produced detonates the ^ Jimmy Saved the Bank"—A recently witnest in explosive. Some times the contacts are g "How J retreating Huns was surprise you, by F. IV. soldier caused to close a battery circuit thru a J slory that will ^ actual operation by a New York not months ago. To spark coil, the secondary circuit of which M Russel. who came home many ''The Unknown Purple"—A 20th start with, the soldier who related this is connected up with a spark plug, buried m Century drama Ultra-Science and tale was a member of a Company which in the explosive. There are, of course, nu- M of g and merous other schemes, many of them having m Psychology. J had been marching for several days, lV\reless to rest and been provided with time clocks or switches, J New Electrical and J one night when they prepared discovered a large cave. for delaying the explosion, as the official re- g "Movie" Stunts. m get some sleep they Storage Battery— unless the weather ports have frequently indicated. m The "Alkaline" m See Fig. 9. Naturally, Its Operation and Maintenance, by = is quite warm, anyone would rather sleep The open fire place, which is ever a ^ in the open, for obvious source of welcome to the footsore Dough- m J. F. springer. in a cave than out Radio-activity, Part they went to sleep, but boys when they have a chance to stop in a B Experiments in reasons. And so //, by Ivan Crawford. long before morning several of the men captured town, is not always the most J Ball Lightning in the were surprised to smell gas healthy place in the world, for as Fig. 2 m Producing awoke and Laboratory. With Excellent photos. fumes, and, what was more astonishing, a shows, it may contain a high explosive shell m S. IVeisiger, Jr. large number of the men who were sleep- planted within the fire wall, so that when a = by Samuel Finishing for the Amateur, ing in the cave were found to be "gast." good fire is kindled on the hearth the shell B Wood Kluge. Those who had awakened, and who were will be caused to explode, very possibly B by Arno A. B the usual "Constructor", not totally overcome by the gas, at once re- killing all those within the room. Besides "Chemistry", and "Mo- the gast men from the cave and Fig. 3 illustrates how the retreating Ger- M "Wireless", moved Departments, and hun- started to investigate, as no fumes of gas mans often left a trap for the conquering rn chine Shop" other valuable, time-saving had been noticed whatsoever on the pre- troops of the enemy by placing high explo- J dreds of and formulas. vious evening when they had found the sive mines under the trails of cannon and wrinkles, ideas "Dirty work, sure enough," said the machine guns, so that as soon as anyone cave. Sergeant, as he and two of his men started moved the cannon carriage, the spring ac- back in the cave to find out what kind of a tuated pin of the mine would spring up and be detonated, and so the story rolls on new trap the crafty Huns had concocted detonate the explosive, thereby possibly kill- backed by the facts. See Fig. 5. before long they discovered it, planted ing several men. Nor were the German dead allowed to several feet below the earth in the rear of One of the cleverest, altho hellish, tricks rest in peace, for even after life had ceased the cave, and with a small gas tube leading ever played by the retreating Teutonic in their bodies, they must serve the "Father- up to the surface of the ground. They dug hosts probably is that of the "wireless land." This is true "Schrecklichkeit" effi- up the infernal machine, and were as- bomb." Fig. 4 shows this trap in action, ciency to the Teutonic mind, if not to ours. tounded to find that not only did the box and the story of its operation is as follows So the crafty Teutons, when they were contain a small gas generator with a time- Before the enemy retreated, he took care forced to retreat, got into the habit of plant- clock arrangement rigged up to a valve on to place a number of wirelessly operated ing small explosive traps under the dead it, so that gas would be generated and sent bombs in the walls or possibly under the bodies, with the hope in their hearts that into the cave at a certain pre-arranged hour, floor of various dwellings and other build- when the on-marching Yankees or Poilus that also there was a sufficiently large ings, so that in the event the victorious pot on this territory and attempted to clear but quantity of high explosive in the container troops as they entered the town or locality, it up by lifting the dead bodies, they would (Continued on page 669) might set up a wireless set in proximity to meet with unexpected fatalities. See Fig. 6. January. 1919 ELECTRICAL EXPERIMENTER 609 ELECTRIC DEATH TRAPS IN HUN'S RETREAT

(For Description See Opposite Page) roiijTlnlit. IDIS. by E. P. Co 610 ELECTRICAL EXPERIMENTER January, 1919

Submarines in Peace-time Now that the great world cataclysm is practically over, we have to think of many reconstruction problems, and one of these will undoubtedly have to do with many of **- marine as well as military apparata and dovlcas which have been developed and built in unbelievable auantities. For one thing, there will be a super- uity of "submarines"—especially surrendered U-boats. A New York inventor, Mr. George Wall, has proposed and here illustrated a novel use for these superfluous submarines, naonely, to utilize them as freight carriers, and not only to perform this service in the ordinary sense, as has been done when the giant submarine •*Deut8chland" crost the Atlantic Ocean with a cargo, but to arrange for these submarines to pass thru a submarine tunnel for example. Let us consider, as Mr. Wall points out, the freight-handling problem at Manhattan Island, New York, where incoming steanaers are un-

other moving trains or any of its desired joined cars, train despatcher's ofSces, signal Telephoning To and From towers, stations, city exchanges, cities, towns, villages, hamlets, or with that of any regular telephone subscriber. This Moving Trains railroad telephone invention consists of an the apparatus including standard equipmeiit Americans residing in To- connection between the instrument and only comprising the well-known telephonic THREE Messrs. Isidor, Abra- rail is made thru the car wheels, and in ronto, Canada, retardation or repeating coils, ordinary and Samuel Berliner, have in- combination with the ordinary rails prop- ham rolling stock of wheels and axle, requisite vented a moving train telephone erly bonded for the block-signal system, but track where bearing instrumenc from which it is con- apparatus for telephoning to and it will work equally well on any nected to the wheels, and the usual rails, in the the rails are similarly bonded, without re- from trains en route, as depicted re- of a block- properly bonded. This transmission and illustration. This apparatus perrnits voice gard to the absence or presence ception is carried on, it is claimed, without transmission to be made automatically and signal installation. regard to the trains' speeds or of trains thru the ordinarj' car wheel and Telephonic speech or voice transmission directly moving in the same direction, opposite of con- is conducted thru the ordinary existing axle, axle, without the assistance any over at right the rails, directions, trains crossing tributing medium, by a special instrument thru the wheels and down to angles to another, or any other moving it runs and is picked up by connected to the wheel. Thus electrical along which positions, whether this be upon the same track as in the case of a double- track line, or between any tracks. The control of the system differs in no respect from ordinary telephone operation, and arti-

fi c i a 1 amplifiers requiring d e 1 i- cate aojustmeni are not employed. The invention now makes it possible for connection to be made between the train instrument and that of any regular telephone subscriber. Train speed is of no material consequence, for the same results are attained traveling 60 miles an hour as Telephor -d, and Any FIxt Station, Office, or Home, Is Now Pos- and when barely •Ible—Thanks to Recent invention, wnicn Enaoies tne Telephonic Currents to Travel Thru the Car Wheels Along the Ralls to the Nearest Telephone Exchange. moving. January, 1919 ELECTRICAL EXPERIMENTER 611

Submarines in Peace-time loaded In some cases on the piers at the North River. This freight is frequently trans-sblpt by auto-truck or otherwise to points directly across the city. In other words, the goods are often carried thru thickly congested streets over to the East River or in that vicinity. If we had a submarine channel bored thru the solid rock many feet below all of the present subways, it would provide a feasible and economical method of trans-shipping freight from the North to the East River and vice versa. As it is. goods are often shipt by auto-truck or across the city . at considerable expense, or else by boat down the East River, around the Battery and up the North River. This is bound to be so. in some cases, owing to the fact that vessels frequently carry mixt shipments of goods. This scheme is undoubtedly feasible and economically applicable to many shipping localities in various other parts of the world.

CocTTUht. IDX!. by B. P. Co. Thus "Subs" Could Be Economically and Efficiently Used, Wliicli Would Be Applicable in Many Shipping Localities Thruout the World. Where a Great Deal of Shipping Would Have to Be Handled, There Would Be Employed Two Tunnels and Two Sets of Loct

This system also permits telephoning to fectly feasible to control a moving train less operating, several of the leading schools be done from one end of a train to the by telephone from the dispatcher's office at having classes at which young ladies attend. other or to any part of the train. The a distant point. The invention is patented At the present time there has not been a conversation may be held as easily as from in the United States and Canada as well as very large opportunity to place these fair house to house. The tone of the voice is in foreign countries. This new railroad radio graduates, for the reason that the just as clear as with the telephone on a telephone system promises to completely Navy Department controls all the wireless city circuit. One cannot tell that the train revolutionize modem railroading. stations, and it is against their rules to have is moving, as far as the sound in the in- women in any government radio stations. strument is concerned, it is claimed. However, there are many ways in which A working model of a new moving train INDIAN PRINCESS LEARNS women trained as radio operators can help telephone apparatus has been very success- WIRELESS. and have been helping. For one thing, they fully demonstrated by the Canadian Gov- The accompanying photograph shows an can be of considerable aid in helping to ernment Railways on their road by Mr. Indian princess learning wireless telegraphy teach the soldier and sailor "rookies" the W. W. MacFarlane of New York, who —Miss Emily Moran, descendant of a rudiments of radio operating—particularly conducted the tests of his new invention, famous Indian chief. She promptly offered the code, which is always a great stumbling which was tested at Moncton, N. B., Can- her services to her country in this national block to most of them. Women should ada, from July 16, 1917, to March 28, 1918, crisis, and is rapidly learning the art of prove particularly efficient in teaching this inclusive. radio operating so that she can graduate part of the radio art, for they have proven During these tests, which were very com- from clerical work to the wireless room of themselves very adept and successful in plete, the conversations were carried on an ocean liner or possibly a transport. imparting knowledge to students of all ages between the moving train and the dis- Many young women have taken up wire- in our public schools thruout the country. patcher's office in a clear and distinct manner. The engine was cut off from the car and proceeded a mile down the track by orders telephoned from the conductor to the engineer. The engine was then stopt by telephone orders from the conductor, who was on the car, and instructed to come back and couple up again. Then an order was given by the conductor to back up the train and take on the flagman, who had eone back to flag. Before backing up, a telephone message was sent to the dispatcher's office, asking if it was safe to back up, and the answer by telephone from the dispatcher was that this would be all right. After backing up 'o the flagman, the order was received from the dispatcher's office to go ahead to Humphrey's and cross over to the other track and come back to Moncton. Before reaching Humphrey's a second telephone message was received from the dispatcher countermanding the previous order to cross over, but to return to Moncton on the same track, as the train was protected from the rear. All these instructions were transmitted by telephone from the dispatcher's office to the conductor on the car and by him trans- Photo from Paul Thomrson mitted to the engineer by telephone, while Here We See a Weil-Known Indian Princess Learning the Wireless Code. She Is Miss Emily the car was running, showing that it is per- Moran, Descendant of a Famous Indian Chief. 612 ELECTRICAL EXPERIMENTER January. 1919 A New Aerial Smoke Barrage

airplane has surely come into its illustrated and described being due to John the air, but it would in a few minutes pro- THEown during the recent world war. Koltko, of VVatertown, Connecticut. duce a long trailing cloud of black smoke, Hundreds of 'planes were to be seen .\s the front cover and accompanying and it would indeed be quite difficult for an in the air on various sections of the views show, this invention enables an aviator aviator to tell at exactly what point in this great battle-front many times during to quickly send out a large quantity of heavy cloud the enemy 'plane was. the day, their glistening wings sparkling in smoke which will entirely envelop the The technical details of this smoke-pro- the bright sunshine. Pursuer and pursued plane and prevent, or at least make it ex- ducing apparatus for aircraft are quite hurtled thru the simple and it op- air at prodigious erates as fol- speeds. These lows : A s t e e 1 airplane attacks tank is mounted looked all very in the body of tame from the the 'plane with ground until one which there is of them closed in connected a by- on his adversary, pass pipe con- when many a necting with the spectacular battle exhaust of the was enacted. Per- engine. A suit- haps one of the able valve con- most spectacular * trolled from the of all aerial bat- pilot's seat is tles is that men- connected with tioned in a num- this pipe, so that ber of the inter- when it is de- esting stories '^ijj^4^i0 sired to produce that have come a smoke cloud to to us from the envelop the lion-h e a r t e d 'plane, it is only fighters of the necessary to open air, where an en- the valve and al- the e m y 'plane has low engine dropt out of a exhaust to pass cloud, in order into the tank. The tank con- to pounce down and surprise an tains certain unsuspecting flier chemicals which below. Some of ^ when acted upon by the gases from the German avi- the ex- ators used to motor practise this trick h a u s t, produce smoke rapidly regularly, sailing in upward thou- great volume. As the illus- -sands of feet, tration only to suddenly shows, the disappear in a diffusing heads consisting cloud or cloud of c o n i c a 1 1 y- bank. Then the crafty flier shaped drums would suddenly with perforated faces on them, dart out of a are placed around cloud at the side various parts of or at the bottom, the airplane, un- and if a hostile der the wings 'plane happened and along the to be anywhere fuselage. in the vicinity, the factor of surprise would in THE M A G-

practically a 1 1 NETIC SUR- cases be on the VEY VESSEL, side of the "CARNEGIE." emerging w a r- The Magnetic 'plane. jy Survey Vessel, clouds Carnegie, arrived But safely at her would not always home port, Wash- be conveniently ington, D. C, a at hand for SMOKE SENERAimS TANK . CONIAINING MEAVr 0IL5 AND short time ago, carrying on such CHEMICALS FOR GENEBATINS where she was maneuvers. DEf-SE SMOKE AIRPLANE SMOKE FEED PIPE put out of com- is not DETAIL OF TOHOZZLES There 'SMOKESCREEN" 6EHERAT0R mission during now, nor is there Copyright, 1918. by E, I'. Co. the period of the likely to be an in- Smoke Screen, but the war. During her ternational 1 a w Destroyers and Other Vessels Throw a Dense Not Only Can the Naval from the cruise Well This Recently Perfected Invention Causes the Exhaust Gases from on the conduct Battle-plane as Which, When Thus Acted Upon, Pro- Engine to Pass Into a Tank Containing Certain Chemicals Buenos Aires, of aerial warfare Distributed Thru DIftuser Heads About duce a Dense Smoke In Great Quantities. The Smoke Argentina, round to the effect that the Planes. the Horn to Val- battle 'planes for, an enemy 'plane to paraiso, Chile, Callao, Peru, thence thru may not play hide and seek among the tremely difficult good shot on him. This is more the Panama Canal to Newport News, she clouds if they choose to. Wherefore and "plant" a considered that the was in command of Dr. N. W. Edmonds hence, we have the latest invention in aerial apparent when it is simply have a dense clotid and a number of other scientists of the warfare—the "airplane smoke producer"— 'plane would not around it at one point in Government staff. the particular form of this invention here of smoke blown —

January. 1919 ELECTRICAL EXPERIMENTER 613 'The Long Dash"—AWireless Gun Show

BACKED by an absorbing story en- rapidly transmitted, and then the "long and cause a shell to pass thru the target acted and assisted by elaborate dash" or spark is the signal that the gun without killing a few dozen actors standing scenic and stage effects, "The Long will fire. A thirty-eight caliber Colt re- off stage. The truth is, there "ain't no Dash" has proven one of New volver is cleverly arranged inside of the such animal" as a bullet used, but a trusty York's latest and greatest theatrical successes. The play was written by Robert Mears MacKay and Victor Alapes, co- author of "The Boomerang." It has a distinguished cast, including Robert Ede- son, Henry' E. Dixey, Violet Kenililc Cooper, Milicent Evans, and others. The dramatic story revolves around the invention of a marvelous new "radio controlled" cannon. The secret of its operation is stolen by a spy. With the inventor of the gun dead anci the radio code by which the gun is operated lost, many curious and exciting incidents result. Interspersed with all these affairs there is a delightful love story in which two brothers. Paul and John Hazelton, both impersonated by Robert Edeson, are concerned. Xow for the dirty work. Those who have seen this show have undoubtedly wondered just how the wireless controlled gun. a large sized and faithfully reproduced model of which is used on the stage, as the accompanying photographs show, is operated. For it surely does give one, no matter how sophisticated in scientific matters he may be, a genuine dramatic thrill. Robert Edeson. who endeavors to solve the The Wireless Controlled Cannon Speaks—and Hits the BuM's-Eye Every Time. An Exciting mystery of 'the lost code, presses the key Moment from the New York Dramatic Success, "The Long Dash." Mr. Robert Edeson Plays of the wireless transmitter located across the Role of the Radio Genius, V/ho Works Out the Code Which Will Operate the Gun, Its the stage from the gun, and every time he Inventor Having Died. presses the key a crashing blue-white spark several inches long leaps across the spark model cannon and this, operated by a stage assistant stands ready with a string in his gap at the transmitting apparatus. A simi- assistant, produces the explosion whenever hand, and each time the gun fires he yanks lar spark also appears simultaneously at the the gun is fired. another wad of paper out of a previously spark gap fitted on the gun pedestal. Being Bin this is not all, for to lend still more prepared hole in the bull's-eye of the target. of a scientific turn of mind, he eventually enchantment to the seeming mystery of this "Ye gods!" little Willie remarks, Mr. Ede- gets down to tlie point where he can cause pseudo-scientific drama, the target at the son is sure some sharp-shooter, and in truth the gun to train around a circle, and also rear of the stage plays a very important he is, so far as the story of the drama is up and down vertically, besides firing. The eVery time the gun operates an- concerned. controlling signals comprise a number of role, for goes thru the target. At As will be recollected, in the introduction dots or short sparks, and after the proper other "bullet" audience thinks so, for does not a it was mentioned that Mr. Edeson imper- number of these have been transmitted, a least the hole appear in the target each time the gun sonates two roles—that of Paul Hazelton long dash or spark is required to cause the it does, and little Willie in the as well as John Hazelton. In another act particular function in hand to take place. fires? Sure front row as well as his grand-dad prob- a clever bit of stage work is carried out. Thus when the gun is to be fired, after in the dickens they can and a few words describing it will undoubt- being trained with a previous set of signals ably wonders how small naval cannon right on the stage edly prove of interest. In this scene one of or sparks, a number of short flashes are fire a the brothers sits down in a large high-back, old-fashioned chair, and presently turns the chair with its back to the audience and starts eating at a table. The audience sees the actor's arms moving as he proceeds to eat his dinner, but the old saying that the "hand is quicker than the eye" still holds good to a dot. for right before your very eyes and while the good Mr. Hazelton No. 1 apparently is enjoying his meal an tmseen transposition takes place in a few seconds. The seat of the chair is a spring-actuated atTair and collapses when desired. The actor escapes down thru the bottom of the chair by means of an electrically operated dumb- waiter, or "trap," as it is called in stage parlance, and another actor rises o-' the trap, gets into the chair and carries on the arm movements and other embellishments that go with the assimilation of a hearty door of repast ; and in the meantime the the room opens, and in walks the other brother, Mr. Hazelton No. 2, who is no other than our old friend, Mr. Robert Edeson.

An electrically controlled machine for sorting coffee beans has been invented by a native of Munich.

India has increased its annual coal pro- tons is introduc- A Close-Up View of the Wireless Gun and Ra die Transmitter, with Mr. Edeson Studying It* duction to 12,000,000 and into some mines. Response to Various Dot and Dash CombI nations, from the Play "The Long Dash." ing electrical machinery 614 ELECTRICAL EXPERIMENTER January, 1919

Nikola i esla and His Inventions

By H. Gernsoack AN ANNOUNCEMENT

SEVERAL years ago, wireless, the X-ray, the air- in the course of a plane, or the telephone." discussion, a well- The trouble with Nikolb known journalist Tesla is that he lives a cen- asked me whom I tury ahead of his time. He considered at present the has often been denounced world's greatest inventor. I as a dreamer even by well said: "If j'ou mean the man informed men. He has been who really invented, in other called crazy by others who words, originated and dis- ought to know better. For covered — not merely im- Tesla talks in a language proved what had already that most of us do not as been invented by others, yet understand. But as the then without a shade of years roll on Science more doubt, Nikola Tesla is the and more appreciates hi.* world's greatest inventor, greatness, and begins to pa> not only at present, but in him tribute more and more. all history." In 1893, three years prior My friend was much sur- to the earliest' attempts in prised and voiced his aston- Hertz wave telegraphy. ishment. "Surely," said he, Tesla first described his "you do not mean to place wireless system and took Tesla ahead of such great out patents on a number of men as .Archimedes, Fara- novel devices which were day or Edison?" then but imperfectly under

"That is exactly what 1 stood. Even the electrical mean," I replied, "and be- world at large laughed at fore twenty-five years have these patents. But large elapsed the world at large wireless interests had to pay will echo my opinion." him tribute in the form of "But listen," persisted my real money, because his friend, "who on earth is this "fool" patents were recog- man Tesla anyway? What nized to be fundamental. He are his wonderful inven- actually antedated every important wireless invention tions, what great thing has the he ever done? How is it A few weeks ago Princess Lwoff-Parlaghy. that the world at large does Nikola Tesla, from a Painting by th e Famous world read thru news dis- This Picture Has Never Been Published Before. not know him?" patches of a great wireless "To begin with, and the better to impress you," I replied, "Tesla discovery—the static eliminator. But Tesla had not only patented has secured more than one hundred patents on inventions, many systems overcoming this and other forms of interference but had of which have proved revolutionary. Science accords to him over actually constructed and successfully operated devices years ago conditions static interference 75 original discoveries, not mere mechanical improvements. Tesla in Colorado, under where was originator. Like troublesome to an extraordinary degree. A photograph of one is an originator in the sense that Faraday was an this he is a form of his apparatus is published with a note from him for the the latter he is a pioneer blazing the trail ; aside from Electrical discoverer of the very highest order." first time elsewhere in this issue of the Experimenter "Ninety percent of the entire electrical industry pays tribute to And so it goes. The world smiles an unbelieving smile, but Tesla's alternat- invariably sets the world aright. his genius. All electrical machinery using or generating master mind transmission I first read about Tesla in a well-known German weekly publica- ing current is due to Tesla. High tension current 15 years old. The Editor of that publi- without which our long distance trolley cars, our electrified lines, tion when I was less than picture on full page and paid high tribute our subways would be impossible, arc due to the genius of Tesla. cation reproduced his a world's coming greatest electrician. The Tesla Induction Motor, the Tesla Rotary Copyerter, the to Tesla, hailing him as the Engineer, President of the American In- Tesla Phase System of Power Transmission, the Tesla Steam and H. W. Buck, Chief others, said: "The work of Gas Turbine and the Tesla Coil and Oscillation Transformer are stitute of Electrical Engineers, among in his great conception of his rotary field seems to perhaps his better known inventions. Nikola Tesla does of the greatest feats of imagination which has ever been "As to your last question, namely, why the world at large me one he has com- attained by human mind." not know Tesla, it is answered best by stating that British Association, commenting upon mitted the unpardonable crime of not having a permanent press Lord Kelvin, before the Transformer exhibited, said: "This is a wonderful agent to shout his greatness from the housetops. Then, too, most the Tesla induction coil destined to be of great of Tesla's inventions, at least to the public mind, are more or less development of the intangible on account of the fact that they are very technical and, importance."

the wireless : "Mr. Tesla's therefore, do not catch the popular imagination, as, for instance. Electrical Review, commenting upon — : "

January. 1919 ELECTRICAL EXPERIMENTER 615 researches in this field have attracted world-wide attention, and Some of Tesla's inventions have been of far-reaching impor- his is undoubtedly the master mind." tance in the War. The resources and productive powers of the Der Electro-Technische Ameigcr, Berlin, and Elektrizitdt, Leip- country have been greatly increased thru extended use of his zig, Germany, (commenting upon Tesla's work) : "It is a com- system of alternating current transmission and transformation of bination of the grandest power of technical performance with the energy. Nearly ten million horsepower of water falls have been most vivid imagination, such as harnest by this means, thus sav- has never before manifested itself ^^^^^^^™^^™^^^^^™™ ^^^^^^^^"^^^^"— ^^^ ing forty percent of the entire in the human mind." coal output of the United States. Brigadier Allen, of the United BY special arrangement the ELECTRICAL The railroads have been electrified States War Department Ccom- EXPERIMENTER will, beginning with and his induction motor has revo- menting upon Tesla's Turbine) : lutionized the steel industry and the next issue, publish a series of articles en- "Something new in the world. operation of factories. His elec- titled "My Inventions", by Nikola Tesla. The Officers are greatly impressed tric drive has been adopted on the great inventor will contribute a signed article with it." largest cruisers and battleships as While studying abroad I read monthly, which articles will run for several the most perfect means of pro- every scrap of his work I could years. Most of this material has never ap- pulsion. His wireless inventions lay my hands on. I performed have proved indispensable and his peared in print before. The articles will be most of his high frequency ex- oscillatory apparatus has been of publisht in book form later. We consider this periments, and the more I saw of inestimable service in chirurgical his work the more imprest I be- announcement the most important we ever and therapeutic treatment in the came. Some years ago as Editor made. THE PUBLISHERS. field. of Modern Electrics, I met him in The technical prints abound with a New York shop where his fa- wm^^^^mm^^^^^^^^^^^ ^^m^mmm^^mm^^^^^mmm^m his work, his inventions, his dis- mous turbine models were first coveries. The following is only built. I was fascinated with the tall, gaunt man, then about 50 a partial list of terms now adopted and published in text books years old, but looking less than 30. His extraordinary face, with and technical works his deep set blue eyes, proclaimed the intense thinker—the philos- Tesla two-phase, three-phase, Tesla electro-therapy opher. A few minutes' chat with him left me more than ever multi-phase, poly-phase sys- Tesla electrical massage convinced of his greatness. tem of power transmission Tesla currents Further contacts during the past few years still enhanced my Tesla principle Tesla transmission opinion of him. Tesla is a man of extraordinary knowledge. He Tesla rotating magnetic field Teslaic experiments is remarkably well read and has a photographic memory whereby Tesla rotating magnetic field Tesla capacity it is possible for him to recite page after page of nearly every transformer Tesla arclight system classical work, be it Goethe, Voltaire or Shakespeare. He speaks Tesla induction motor Tesla third brush regulation and writes twelve languages. He is an accomplished calculator, Tesla split-phase motor Tesla devices who has Httle use for tables and text-books and holds the sliding Tesla system of distribution Tesla sparks rule in contempt. Tesla has received numerous honors and dis- Tesla rotary transformer Tesla arrangements ' tinctions of all kinds. He is a knight of several orders, holder of Tesla system of transforma- Tesla theory many titles and diplomas. Some time ago he was awarded the tion by condenser discharges Tesla point Elliott Cresson gold medal by the Franklin Institute and last year Tesla coil Tesla Steam Turbine the Edison medal by the American Institute of Electrical Engi- Tesla oscillation transformer Tesla Gas Turbine neers. Many extraordinary distinctions have been offered to him Tesla electrical oscillator Tesla Water Turbine which he has declined. As of timely interest one instance may be Tesla mechanical oscillator Tesla Pump mentioned. At the announcement of Tesla's high frequency dis- Tesla high frequency machines Tesla Compressor coveries, while the former Emperor of Germany was all-powerful Tesla dynamo-electric oscilla- Tesla Igniter and great men were eager for his favors, Tesla received an invita- tor Tesla condensers tion from him and the Empress to repeat his celebrated experi- Tesla tube Tesla electro-static field Tesla effects ments at the Royal Palace in Berlin. He forgot all about it and Tesla lamp did not answer for one year, when he politely apologized for his Tesla high-potential methods Tesla wireless system inability to avail himself of the honor. Later the invitation was Tesla inductor Tesla methods of wireless renewed and nearly two years past before Tesla answered to the Tesla marvels transmission transmitter same effect. After a lapse of time, however, upon the announce- Tesla impedence phenomena Tesla magnifying ment of another impor- Tesla telautomata tant invention, he re- ——li^^^^^—^^^^^^^^^— ^— Tesla insulation ceived the invitation for Tesla underground the third time, with the transmission, etc. TESLA, in the opinion of authorities, today is con- assurance that an alto- NIKOLA The other night the to the greatest inventor all times. Tesla has gether unusual honor ceded be of Editors of the "Ex- his- was reserved for him. more original inventions to his credit than any other man in perimenter had the opportunity of passing "Well, boys," said tory. He is considered greater than Archimedes, Faraday, or an evening with Tesla. Tesla to his assistants Edison. His basic, as well as revolutionary, discoveries for sheer after he laid the invi- We talked about many audacity have no equal in the annals of the world. His master tation which he never things, so interesting, the intellectual world. answered aside, "the mind is easily one of the seven wonders of that I will reserve them Ejnperor must be a H. GERNSBACK. for another article—but mostly, of course, the great man. I do not conversation centered think that I would be mm^mmmmmmmm^^^^^mm^mm^î^^^^^ i^^^^^^^î^^^î^^^m^^m^^^mim himself. capable of acting in this about Tesla him, are of our great way if I were in his place." Perhaps the most remarkable tribute "Dr. Tesla," I said to "you aware But was paid to him when he made his famous experiments in Colo- admiration for you, which may or may not be important. elder, do- the great public knows little of your mark. Even many of those rado in 1899. It was by J. Pierpont Morgan, the who think that you are nated $150,000, which enabled Tesla to produce artificial light- technically educated—excuse the frankness— ning and incidentally to electrify the entire earth. (Continued on page 657) 616 ELECTRICAL EXPERIMENTER January, 1919 "Odd Photo" Contest

WELL, Readers, what do you think am told, was caused by the film being held in the shadows cast by a tree, when the of this perfect galaxy of "Odd wound too fast, thereby causing static elec- sun was a crescent. It will be noticed that Photos"? Fit for a king, eh. tricity. the shadows are all shaped like a crescent That's what we thoticht and. so \\ hat caused the lines to be in double, — in fact, an exact image of the sun at that decided to publish them. Have or in pairs? Can anyone explain this? time. The cxplanalion of this is that the you ever tried to enter a photo in our "Odd What causes the lines to have those pe- small apertures in the foliage acted like Photo" contest? Xow is the time. Just culiar peaks? small lenses and projected the image of

look over this collection, gathered from all I hope that your readers can answer it. the sun on to the ground, or in this case the parts of the countn', and you will gain a W'm. P. Ullrich, Ansonin. Conn. sheet. During the eclipse the ground and clear idea of just what we are after in this the sides of houses were covered all over direction. We want brainy pictures as well LIGHTNING AT THE SEASHORE with these minute crescents, and it was as freak photos. Electrical. Radio and very interesting to watch them and to note

Sci''"Ti-''' ?n!i'ecti '.;i\e vnii :i wide field to Here is an excellent photograph of an how they corresponded with the changing

' Myttlo Shadowi Ca»« By Solar I '. Ecllpie.—J. L. Clifford. ,

Anothtr "Ball Llihtnlnfl." Photo No.

choose from. See announcement of "Odd electrical storm at the seashore. imatres of the sun on this particular oc- Photo" contest elsewhere in this issue. Last August, while at the seashore, 1 casion. James L. Clifford, t was awakened about 1 A. M. by the loud Evansville, Ind. WELDING CAR TRACKS AT NIGHT crashes of a storm. The flashes were very bright, so I got out my camera. Herewith Herewith is an interesting night picture is the best picture I obtained. In the fore- A 2-HEADED MAN of men welding car tracks in Buffalo. The ground is a boys' camp and the board walk. welding, of course, is The plioto herewith, altho it does not electric, the trolley The beach can be made out very clearly. wire being tapt and a wire fastened to a bear any relation to electricity or radio, C. M. Fairbanks, Ocean City, N. J. weight placed on the track, making the you will admit is odd. It is prized especially connections. The 550 volt current is re- because of its history. The photo itself is duced thru a bank of resistance grids car- MYSTIC SHADOWS CAST BY a double duplicate of my hoincly physiog- ried on a cart. The men are equipt with a SOLAR ECLIPSE nomy and was taken under several difficul- heavy glass mask of special design, to pro- ties. In the first place I was home with the tect their eyes and ears. One of the many interesting phenomena mumps and the measles and, being at a Kenneth Strickfaden, Xew York City. occasioned by a partial eclipse of the smi loss for something to do, I started to is the shape of the shadows cast by the pester my peaceful camera. Secondly, I light filtering thru the trees. The present i-as alone and had to take the picture my- IS IT AN A. C. OSCILLOGRAM? picture is one taken during the eclipse of self. Thirdly, my camera is a box type, and I here present a print which resembles June the eighth, at a spot where the eclipse I had to rig un a series of wire rings, ^o an alternating current oscillogram. This, I was 85 per cent. The picture is of a sheet (Continued on page 673) — —

617 January. 1919 ELECTRICAL EXPERIMENTER FOR ELECTRICAL DENTAL^AUTo ^^^ Rritish 'Plane Gail Coast 20 Miles to There's nothing like having a "pull" especially if you happen to be one of Safety Camp Upton's sons. Just think of the cept for slight damages which may follow a pleasure of sitting down in this elaborately In a recent report from an aviation camp landing. They are so balanced and the equipt dental palace—why we'll bet the behind the British Hnes in France comes the the absolutely foolproof wings so arranged that when the engine D. D. S. hates to leave it at night. Believe news that while — they glide gradually and easily to the "Doc." when he says "We send them airplane has possibly not yet been invented, stops attention. away with a smile!" in the opinion of American pilots who are earth, without the pilot's In examining Upton's portable dental car we note that electricity is used to almost the same extent in this portable office as

it is used in the private practise of the modern dentist. Altho Camp Upton has an elaborate dental equipment, with twenty- two chairs at the Dental Infir- mary, five more for the Depot Brigade, and three at the Base Hospital, and a staff of Assist- ant Dental Surgeons, there is still need for the dental ambu- lance, for among the thousands of soldiers who pass thru the cantonment, there are many who for various reasons cannot come to any one of the three permanent offices. With its complete equipment, no case is too severe to be treated, a fact which is ad- mirably borne out by the records of the office. As many as a hundred patients have been treated in a day, the work including everything from prelim- inary examination to the relief of aching molars or the filling of cavities. The dental chair, which we here see so well "filled" with a 180 pound Upton patient, with its fountain cuspidor is exactly similar to the chairs found in

Far Can I Glide or any well-appointed office. Con- The One Great Problem Confronting the Flying World Has Always Been—"How is-Twenty Miles; that l.s. If You Have One of veniently located on one side is CoLtffcoast, My Engine Should Stop?" The Answer 4'j^™y ^"^^3 'Planes, One of Which Has Glided That Distance in an Actual Test. the familiar bracket table for t= British instruments, while in front of remark- in a British airdrome the newest The following test shows how the chair are the electric motor and exten- working machines have very nearly solved ably stable these airplanes are: A pilot sion arm of the all important and nerve British problem. climbed to a sufficient height, stopt his en- twiddling drill. The foot control is on the the Left to themselves gine and took his hands off the controls, these latest machines merely keeping his feet on the rudder bar. will make their way He steered for an airdrome twenty miles safely to earth, ex- away and, except for keeping it straight, he let the airplane do what it liked. It traveled the whole twenty miles as steadily as floor behind the chair. a bicycle coasting down a long, straight and in- Overhead are two gentle hill. candescent lamps in The accompanying illustration shows just special reflectors, what such a performance means to the avi- adequate which assure ator, who has heretofore always been in and well-directed il- danger of being forced to volplane down Even a lumination. at a sharp angle as soon as the engine stopt. lathe is motor-driven Thus the aviator had to make a landing on hand. while coming down at a fairly sharp angle, electric equip- The and in some cases the plane has practically operates at six ment "dropt out of the sky," killing the aviator current being volts, and demolishing the machine. provided by a three- Just think what it will mean to the bird- storage battery. 'ell men when they can volplane down a dis- This battery provides tance of twenty miles, such as from Mine- sufficient energy to ola, L. I., to Governor's Island, or vice operate the entire versa. It's really a wonder our flying ma- electric equipment for chine inventors have not perfected such a a two weeks' period. device before this, when we stop to think It is the only source of the many military aviators who have of electric energy in had their engines stall when over the Ger- the outfit, for the man lines, which invariably meant they had aulo-encine is not fit- to descend in enemy territory, with subse- led with a dynamo. quent capture.. The cities and towns shown .\ rectilier enables the about New York City in the accompanying 1 lattery to be charged from any lamp socket, view are all situated approximately 20 miles however. Also this distant. permits current to be ':(ken direct from the Electrical apparatus taking current from lighting mains when a light socket has been invented by a French the battery is low. scientist to purify the air in a room by All Had a Real Pull with the Dental The Camp Upton Boys ''halo courtesy Nciv literally pumping it into a reserxoir and '.'Docs," for Electricity Provided Every Convenience Necessary washing it. for Pulling and Filling Aching Molars "Painlessly." York Edison Co. —a

618 ELECTRICAL EXPERIMENTER January'. 1919 New Flashlight Cuts Off After One Minute

The newly invented and extremely novel feature results in a great saving of battery one minute, depending upon the period for electrical flashlight here illustrated incor- energy, particularly in such forms of the which it is set to operate, expands and porates a feature not possest by any other dry battery electric lamp as those made in opens the push button contact trigger. A flashlight so far developed, in that when the form of an ordinary lantern, which spiral spring on the push button rod tends the push button is deprest the lamp circuit are provided with a switch instead of a always to push it outward. i« kepi closed for a predetermined and spe- push button, and which the owners there- of have a great habit of thinking that because it is an electric lantern, it will stand /.5 V lamp almost any abuse. It would make the heart Dry Ce// of any good electrician flutter with extreme anxiety to watch some users of these electric lanterns and see them close the switch "'"JT^'' and then forget it—a dry battery to them is

a veritable electric djTiamo ; they never give a thought to the fact that the dry cells used in every one of these flashlights, will give several times the life if they would but open the switch or button periodically—say at Sloir acting intervals of one-quarter to one-half minute air valve — in order to give the battery a chance to trip pin recuperate.

It is to guard against just such misuses of the electric flashlight that the inventor Push of the present automatic cut-off push but- buXon ton, Mr. G. H. Parsons of Stamford, Conn., has evolved and patented the device here illustrated. One illustration shows the ex- terior of his new flashlight, called the "Tempolight," while the second illustration shows a diagramatic view of the interior arrangements. These are simple and comprise the usual lamp bulb, a dry cell, and a circuit-closer or push button, to which he You Push the Button of This Flashlight— attaches a small air bellows. When the Later the Lamp Extinguislles Itself Minute button is deprest this bellows is also de- Automatically. Result—a Saving In Battery Power and Life. prest, and the air exhausted within it. By means of a slow acting air valve or other Here Is the Secret of the Automatic Cut-off of the Flashlight that Opens Its and arrangement, the bellows, Mechanism cific length of time, such as one minute, suitable after an Lamp Circuit After Burning for a Minute. length it then opens the circuit automatically. This appreciable of time of one-half to A Small Air Bellows Does the Trick.

FOOLING THE DRAFT BOARD?— sound producer is similar to a telephone The sound producer is provided with IT CAN'T BE DONE. receiver except in one very important re- three lugs to hold it away from the ear, so spect—the core is of soft iron and is not that the sound will be transmitted solely by sad and distressing fact has been magnetized. This results in eliminating air conduction. By simply turning the in- THEbrought forth that to escape a the variability due to demagnetization and dicator from 100 to zero, one can cause the righteous duty, one that every full- doubles the pitch, so that the ordinary 60 sound to increase from the point at which blooded American should be proud it is just perceptible to one of normal hear- to fulfill, there are amongst us mor- ing, the threshold of audition, or 100 per in this free land, a new generation tals cent, acuity, to a degree of intensity at small in numbers, to be sure who dehber- — which failure to perceive it indicates that evade the greatest of all ately seek to the subject has no practical hearing. In things the protection of the Stars and — addition to the variable receiver, there is a the preservation of the Union. Stripes and supplementary one that always operates at Amongst the false claims is that of par- maximum intensity, irrespective of the tial or iolal deajness. loudness of the other. The French military specialists have al- In the usual test for the acuity of hear- ready experienced considerable difficulty in ing, only the variable receiver is used. As this direction. It appears that the malin- the subject holds this to the ear, the pointer gerer most difficult to detect is the one is gradually moved from zero to a point on claiming completi loss of hearing in one the scale is reached, that would normally ear. A moment's thought will show why indicate very defective or almost no hear- this should be. Were only partial deafness ing for the good ear. claimed it would not be difficult to trap The very nature of the test, it will be him, as he could not possibly be consistent noted facilitates the detection of fraud, in all his statements thruout an extended because the better he can hear in the al- ear, the less he will hear series of tests ; but, with complete uni- leged defective lateral deafness as the claim, he simply and in the other—a condition just the opposite uniformly replies in the negative to all tests of what he might expect, so that when he applied to the alleged defective ear. makes his usual negative reply he is for Dr. R. R. Brownfield has devised a test once telling the truth and trapping himself. which not only definitely determines the Under these conditions the sound appears acuity of hearing in either ear, but also to come in some mysterious way from a quickly detects the unilateral malingerer. point at the center of the head; and if the In the device as evolved by Dr. Brown- two ears are approximately equal in acuity, field batteries and make-and-break contacts there is absolutely no possibility of indenti- are entirely dispensed with. The ordinary fying the gradually increasing soiind in the 110 volt alternating commercial lighting supposedly good ear until a point is reached Tries to Fool the Draft Board The "Slacker" on the scale away beyond the reading that current is used. The variable current is — But Here's the Electric Telephone "Hear- produced by a potentiometer, and is vari- ing Test" Apparatus that Fools the Would-be would be obtained when the loud receiver is able from an absolute zero to maximum. Shirker. disconnected. Hence in the case of the pre- No vibrating iron is used, and the maxi- tender, the physician has only to repeat the mum strength of current employed is de- cycle current produces 240 vibrations per test with the loud receiver disconnected, pendent on no factor except the ratio of second—about equal to the average tone and a totally different reading will be the electrical resistances employed. The used in conversation. secured, thus proving the deceit. — ;

January, 1919 ELECTRICAL EXPERIMENTER 619

Wintertime Uses for the Electric Fan By PAULINE GINSBERG

AS it ever occurred to you that clothes outdoors. If the windows are kept odor will have vanished in a much shorter the electric fan can be used to open both at the top and bottom, you will time than had it not been used. Incidently great advantage in the wintertime be surprised how nicely they will dry. dust will have been prevented from settling H as a labor on the wet paint and time also, it having dried saver? Probably it more quickly, there At Left; Fan Used as Forced Draft has not. This is but — will be a marked for the Furnace. Try It and You Will natural on account Be Surprised. luster added to the of the popular idea painted surface. The that the fan has fan can also be only one mission, played on any small that of cooling the article that has been air. What the fan painted or enameled, really does do is to such as a kitchen circulate it. By im- chair or table. pelling circulation. Gas heaters were for instance, about never in such favor the body, the dis- as they were last placement of the year and will be this warm air for the year (the coal prob- cooler, as well as letn still being the surface evaporation chief reason). As a accordingly gives a rule, with the on- cooling sensation, coming of a sub- but in hot weather stitute, some un- such as in July, the favorable feature is forced air from the bound to spring up fan does not change —in this case the re- for the cooler, it be- duction of humidity ing equally warm —the gas flame con- both indoors and suming -a high per- out and the fan centage of the sometimes causes precious vapor more discomfort which contains the than comfort. As oxygen, so necessary many of us have en- to our lungs. The tertained the idea electric fan again that the fan cools clears the situation. the air, naturally the Place a pan about fan was invariably three-quarters full hustled to a secluded of water anywhere nook in the attic or ' convenient, so that down the cellar un- the fan can play di- til the warm zephyrs of the next spring The fan in the kitchen window solves a rectly across it. Over the pan put a thin reminded us that it was "fan-time" again. problem that confronts every housewife board or piece of heavy cardboard, which A few suggestions are here given for what to do to prevent cooking odors and ha--, been perforated a number of times, so the wintertime utility of electric fans, and smoke from spreading over the whole that small wicks or pieces of cloth can fit eventually house? It is you particularly annoying when snugly into the perforations. They should will find a num- friends pay a be long enough to pass down into the water. ber of other uses visit. Any The board or cardboard should be of the to which the elec- handy piece of correct size so as to exactly suit the handles, tric fan can be board the length and so be held in position ; it should not employed with of the window be blown off by the fan. benefit. can be attached This arrangement need not necessarily be kept for a great When the mas- as a shelf. It length of time in one room, it ter of the house should be about but can be employed for - a short period in every room, (or was it the three quarters Tin Tabs Ti n or Cardscard Tubes especially in bedrooms and sick janitor?) goes of an inch thick rooms to Stockings and promote comfort and good respiration, down to the eel- and can be fast- Drying Removing Odors Gloves. which in turn produce sound healthful from the lar, and after ened in place sleep. Kitchen. t. j u » A fan should invariably much ado about with a pair of be kept in the sick room so as to insure good ventilation. the furnace (no, brackets and a few screws. On this the fan It sliould of course be turned away, and at not "nothing"), finally makes a heroic at- is placed so as to face the open window a considerable distance tempt at starting a fire on a sultry day and and create a strong suction. In a short from the patient. It will greatly ease his suffering it won't work—what to do for a forced time the smoke and odors will have van- and discomfort which come from the draft? Just apply a fan opposite the front ished. Also to beautify the kitchen a flower difficulty of breathing and or side ashpit door of the furnace as here- or two may adorn the other end of the from the inabil- with illustrated, and the fire will soon be shelf. ity to sleep. The crackling away merrily. Along this same Something we all dislike is the unpleasant fan can be kept line of the heating problem it can often be odor that is the result of a room or rooms placed behind or in front of the steam radi- having just going at inter- ator to circulate the air around and thru been painted. vals and near a slightly low- it so that the room is heated more rapidly With the win- Drying Photo Negatives and evenly. dows kept open e r e d window. Quickly. Something that many women will ap- a few inches at As the impure preciate is the use of the fan in the laundry the top and bot- air rises and escapes thru the upper opening of for drying clothes. You will notice, in the tom and with the window, and the pure air enters thru the lower section, third photograph, how the fan is placed our friend, the a good plan away from the clothes lines in order to give electric fan, would he to have a small shelf made to hold the fan near the upper opening, a freer circulation of air so that it passes kept going, the the suction over all the pumping out the impure air. It should also clothes, and has therefore al- Humidifying and Deodor- Pa'.nt will dry most the effect of a light wind were the Izlng. quickly and the (Continued on page 654) 620 ELECTRICAL EXPERIMENTER January, 1919 Popular Astronomy GIANT JUPITER AND HIS NINE MOONS By ISABEL M. LEWIS

CopyrlBht. 1918, by E. P. Co. JUDlter as Seen from Its Nearest Moon—Satellite V. This Tiny Moon Is Only 67,000 Miles from the Surface of Jupiter. Its Diameter the of Another Is Less Than 100 iviiies. The Black Spot on the Face of Jupiter Is Shadow Moon Projected onto the Giant Planet.

most beautiful object in the serves to distinguish it from the golden The fact that these tiny points of light yellow glow of Jupiter. were THEmidnight sk>' during these winter actually revolving around the great telescopes of two or months is the planet Jupiter, which Even the smallest planet was soon detected by the famous his- will continue to be in excellent posi- three inch aperture will show the four astronomer and we can imagine with what the first tion for observation far into the toric moons of Jupiter which were breathless interest he observed these satel- spring. Upon Xew Year's Day Jupiter will celestial objects to be discovered when lites of another world whose discovery telescope to the be in opposition to the sun and llicrefort Galileo turned his crude de.ilt such a severe blow to the old directly on the meridian at midnit;ht. It is heavens in the year 1610. Ptolemaic theory that the earth was the then seen at its best and will be visible center of the universe. It was not imtil thruout the night, rising in the east as the the great telescopes of modern tiines were sun sets and setting in the west at sunrise. invented that the five additional moons of Jupiter shines by reflected sunlight with Jupiter w^ere discovered. The four satel- twice the brilliancy of the brightest of the lites first observed by Galileo were fanci- fully stars, Sirius. When seen during the mid- named lo, Europa, Ganymede and night hours the remarkable, unflickering Callisto, in the order of their distances out- brightness of this largest and most dis- ward from the planet, but these names arc tinguished member of the solar system at rarely used now, the satellites being desig- scintil- once serves to set it apart from the nated for convenience I, II, III and IV, lating stars far beyond. respectively. The first of the new satel- that_ sur- There is but one planet, Venus, lites to be discovered was Satellite V. which in brilliancy, and as V'enus passes Jupiter is the nearest to Jupiter of all the nine departs more than forty-eight de- never moons. It is an extremely small body, not grees from the sun Jupiter always shines more than one hundred miles in diameter, without a rival at midnight. To one who UPlTtf^' and to discover this tiny body as it skirted has observed the two planets together the brilliancy rapidly around . the great planet within silvery radiance and surpassing of Jupiter and the Earth. Comparative Size sixty-seven thousand miles of its surface, of \cnus. due not to its size, but to its 90,000 Miles in Diameter, Jupiter's Mass Is comparative nearness to the earth, at once 300 Times That of the Earth. nearly lost in tlie glaring rays, v.as a difti- January, 1919 ELECTRICAL EXPERIMENTER 621

twelve hours at a distance of suddenly disappears from the observer's only sixty-seven thousand miles view, tho it may be considerably to one from its surface we realize side of the planet. Its reappearance later what tremendous differences on is just as sudden, or it may pass out of exist in the distances and peri- the shadow while hidden ods of revolution of the nine from us behind the disk of the planet, in moons. There is also great dis- which case its parity in the sizes of the vari- reappearance is invisible from the earth. ous moons. The five moons The occultations of the satellites, or, in discovered in modern times are other words, their disappearance behind the all excessively faint and there- planet's disk, are also interesting phenomena fore extremely small. The di- to observe, as are their "transits" across ameter of the largest of these, the disk of the planet as the satellite passes Satellite V, is less than one in front of the planet. Not only the satel- hundred miles. On the other lite itself but its shadow as well can be hand, the four historic moons seen, a small black dot passing over of Jupiter are of planetary di- the surface of mensions. The smallest, Satel- Jupiter. The satellite is totally eclipsing lite II, is slightly larger than the sun for this small dark portion our own moon, while the lar- of the planet. Two satellites and their gest, Satellite III, has a diame- shadows are frequently seen crossing the ter according to measurements face of the planet at the same time. It is made with the 40 in. Yerkes re- possible to observe all the phenomena of fractor in 1916, of three thou- the satellites' transits and shadows, eclipses sand nine hundred and eight and occultations with very smaM telescope's. miles, which is only four hun- From observations of the eclipses of dred miles less than the diam- Jupiter's satellites the important discovery Jupiter Photographed October 19, 1915, with the 24-Inch eter of Mars. The periods of of the finite velocity of light was first made Refractor by E. C. Slipher of the Lowell Observatory. revolution of these four satel- as far back lites range from one day as the year 1675. and eighteen hours for the Faint surface markings have been made cult feat even for an experienced observer. nearest, which is about two hundred and out at certain times on the largest of the It was accomplished, however, by Prof. sixty-one thousand miles from the center four satellites, Satellite III, and also on Barnard with the great Lick refractor in of Jupiter, to sixteen days and sixteen and Satellite I, or lo. Observations of the 1892. Satellite V is hopelessly beyond the one-half hours for the most distant, which markings on the former seem to indicate reach of any but the greatest telescopes, as is more than one million one hundred and that it always keeps the same face turned are also the four satellites discovered since sixty thousand miles from the planet. toward Jupiter as does our own to- that date. In fact, most of these tiny These four moons of Jupiter are most in- moon moons are observed photographically. Satel- teresting members of the solar svstem. ward the earth. lites VI and VII were discovered photo- They are so near to the great planet that There are also reasons for believing that graphically in 1905. They are both about they are continually dipping into his huge the equatorial regions of Satellite I are seven million miles from the planet and shadow and experiencing an eclipse of the light colored and the polar regions dark. their paths loop thru one another; they sun's rays, which, owing to the nearness are, moreover, highly inclined to each other and great size of Jupiter, lasts for two or at an angle of nearly thirty degrees. When three hours. At times of eclipse the moon (Cnntinurd on page 668) nearest together they are separated by a distance of two million miles. Two more extremely small bodies, known as Satellites VIII and IX, have been discovered quite recently, one at Greenwich, England, in 1908, the other at the Lick Observatory in 1914. These excessively faint bodies are the most remote satellites of Jupiter and they are of particular interest because they travel around the planet in a direction opposite to the direction of revolution prevailing in the solar system. The ninth and most distant satellite of Saturn also retro-

grades ; that is, it revolves in a clockwise rather than a counter-clockwise direction around the planet. One explanation given for this peculiarity of the outermost satellites of Jupiter and Saturn is that this backward revolution around the planet is more stable when the satellites are at great distances from the primary and the gravi- tational control that the planet exerts, therefore weak. The moons of the planets are, of course, subject to the attraction of the sun as well as to the attraction of the controlling planet, and the greater the distance of the satellite from the planet the stronger the pull exerted by the sun and the weaker the bonds that bind such a moon to the planet. Beyond a certain limit it would be impossible for the planet to hold the satellite against the sun's greater attraction and the satellite would leave the planet to revolve directly around the sun, thereby becoming a planet. It appears that as this danger limit is neared it is safer for the satellite to "back" around the planet than to follow the usual "west to east" direction of revolution. The eighth satellite of Jupiter is more than fourteen million and the ninth more than fifteen million miles from the parent planet and they require about two years and three years, respectively, to complete one trip around How Immense This Monster Planet Is,—the Largest of Our Planetary System,—Can Be Jupiter. When we consider that Satellite Judged Best by This Illustration. If We Took Eleven Globes the Size of Our Earth, They V darts around the planet in less than Could All Revolve Within Jupiter Without Touching Each Other, and Still Have Room to Spare. 622 ELECTRICAL EXPERIMENTER January, 1919 An All -Electric Hot Air Balloon

captive balloon as used by the and after a short time the heated air rush- point to another. Either the autoialbile engine or a separate gasoline engine moimt- THEAllied armies at tlie present time is ing up into the balloon causes the envelope drives a dynamo, which sup- invariably filled with hydrogen or to become very light and it rises in the air. ed on the truck healer in the other gas supplied from steel bottles Some of these balloons will travel for plies current for an electric of suitable clutches, the containing this gas stored at a high miles, and years ago it was not an uncom- balloon. By means engme may be caused to drive the dynamo, pressure, or else it is obtained from manu- mon sight in Europe to see hot-air balloons drive, it be con- facturing supply stations on the field. The ascend with several men. or else thru a chain may nected up to rotate the cable winch drum. first balloons ever used—the old "Mont- There has always been, however, a seri- makes connection to a duplex golfieres"' of 1783—were made to rise by ous objection to a hot-air balloon where The dynamo power cable reeled around the drum, and means of hot air, for, as we all know, the heater was of the flame or similar type. this leads up to the balloon basket. Also the telephone circuit is carried up to the balloon thru the drum or otherwise, so that those on the ground are in telephonic connection at all times with the observer in the balloon basket, and under battle conditions he would also be in telephonic communication at all times with "field head quarters," so as to report the position of enemy guns, troops, etc. Referring to the balloon in detail, we find that it is provided with an electric grid heater, and also a motor-driven blower and connecting tube, so that whenever the blower is operated, air is pumped up into the balloon envelope, the air passing thru the electric grid heater. The balloon bag is fitted with a suitable damper in the lower opening and a relief valve at the top in the usual manner, the relief valve being connected to the observer's basket by means of a small rope. When it is desired to descend, the observer may open the motor blower switch in the basket, and thus aid the hauling in of the balloon, for as the temperature of the air within the balloon bag falls the balloon naturally tends to descend toward the earth.

8,700,000 AMERICAN HOMES LIGHTED BY ELEC- TRICITY. From the compilation made by ihe Society for Electrical Develop- ment it is shown that there are 20,689,000 families in this country, of which 7.000,000 have yearly in- comes of $900 or more. However, the yearly average family income before the war was under $626. Over 13,000.000 families are too poor, too illiterate, or otherwise unfitted to buy electrical goods Over 8,700.000 homes are electrically lighted and 120,000,000 sockets contain Mazda lamps. In over 30,000,000 sockets are carbon lamps. It is estimated that 9,000,- 000 sockets are empty. Homes lighted by other means 15,000.000; some are wired but not Any Degree of Heated Air Balloon, the Air In the Bag Being Kept Contmuaiiy Hot, to A New Form the Balloon connected up for service. Elec- Desired, Electric Heater in the Neck of tie Envelope. Current Is Sent Up to by an service is available in Gasoline Engine-Dynamo Set Mounted on the Truck Below. 7eleP[\<>"^ Connection tric 10,613 Basket from a Air Into Between the Truck and the Observer Aloft Is Available. A Motor-Blower Drives Heated communities of the United States, the Balloon Envelope. compared with 3,54.S communities that are being served with gas.

heated air is lighter than cold air, and will for there was always in this case the con- always rise. If the heated air is of suffi- stant danger of the balloon becoming ELECTRIC SEARCHLIGHTS. Ranges of electrical searchlights vary cient volume, it will also carry a body up ignited, with disastrous results. It has re- between one thousand to two thou- with it, such as a balloon envelope for ex- mained for Mr. James N. Lewis of Detroit, from ample. All of us have seen the simple bal- Michigan, to invent and patent an all-elec- sand yards in foggy weather to ten thou- loons which patriotic Americans are wont tric hot-air balloon, which is illustrated in sand yards or more when the air is very to liberate on the Fourth-of-Ju!y, and which detail in the accompanying illustration. Mr, clear. The average sea range is approxi- are composed of nothing more than a bal- Lewis makes use of an automobile winch to mately six thousand yards, but there are loon-shaped paper bap at the bottom opening haul in the balloon, and to act as a mobile cases on record where ships have been spot- fig- of which there is secured either an ab- station, a trailer being hooked behind the ted at a distance of nine miles. These sorbent wick containing gasoline, or a small winch, in which to carry the balloon bag ures are based on a sixty-inch mirror and a alcohol lamp. We simply light the lamp. and basket while being transported from one twenty-thousand watt arc. January. 1919 ELECTRICAL EXPERIMENTER 623 The City of Splendid Night By AMOS STOTE

A 20th Century poet strolled at night en- softened hours that tread upon the heels of I have wandered down unfavored streets, raptured thru the highways and byways of the noontide of the night, those hours that idle channels from which the thinning Manhattan, agleam in all her nocturnal glory have gained a new, entrancing charm be- traffic of the closing day has been diverted —not one night, but many nights—some moonlit, others rainy, but always—the magic of millions of electric lights threw its spell over him. And as he walked along this street or that, or mayhap thru the park, or along the shimmering Hudson, the very soul of the city seemed to commune with him. The poet's name was Amos Stote, and he has here set down three literary gems describing New York City at night as it appealed to him. IVe like Mr. State's soulful word-pictures of the Greater City electrified—he gives us something to think of besides the lights themselves. Thought is the keystone of all intellectualism. Our poet has given us a new pair of soul spec- tacles thru which to view many splendid sights—which the everyday man never as much as suspects.

New York—"the City of Splendid Night." A Wonderful View of the Theater Section from Times Square—the Hub of Manhattan's Ever-Seething Traffic. The Hotel Astor Appears In the Left Foreground.

cause—because of a man named Edison. into the congested spillways of frivolity. In the old days of shrouded streets, when Here, along these hushed courses, where darkness threw a mantle of mourning over life dozes on the border of gaiety, as an the city, good men went in groups for safety outworn chaperone naps m the antechamber sake. Then only the brave and the brute to the ballroom, here I have seen ancient cruised singly abroad, for of course we ex- doorways with the beauty of the binding cept the gallant, suffering from love's fever. of a rare first edition. But now a million gleams of light insure the Once upon a time periwigged and gouty safety of the streets and give the night- old gentlemen, and haughty grand-dames, bedecked city over to the admiring glances past in and out these doors. On state occa- of those who have learned the beauty that sions, when they ventured forth at night, lies in the silent battlements of commerce; armed servants escorted them and fleet- and in the old homes and highways. (Continued on page 673)

"Blot Out the Stars! Let the Skies Open Every Pore. . . . Fields Are Sodden, Villages Sordid. . . . But Old New Amsterdam Is Glorloui. The Romance of Masonry and Electricity Is Before You. It Is a Drama Done In Pouring Pantomime."

is a habit, born of Manhat- THEREtan, that comes to possess the souls of men who wander thoughtfully. It is the habit of night. Not the star- strewn night of mountain tops where God's myriad incandescents sow the skies. Not those shores concerning which poetic folk write rhapsodies around the central station of the heavens. (To me the moon across the sea is a great searchlight laying a restless path that I long to follow.) No, it is not to mountain or shore, not even to deep, mysterious woods, where the firefly sprinkles sparks amid green leaves, that I would go in quest of those good men who have the habit of night. To these men, and to me, the night of nights is to be found in the rugged, slum- berless zone of Manhattan and its fringes And a "Night In the Park." For Within the Sylvan Solitude the Voice of the City Speakt of resting streets. Perhaps you know those Faintly, and Its Sparkling Eyes Are Veiled with the Romance of Contrast. : —

624 ELECTRICAL EXPERIMENTER January, 1919 ^^ RADIO LEAGUE HONORARY MEMBERS CAPT. WKGBULLARD.U.SN. NIKOLA TESlA. s^AMERICA PROF REGINALD FESSENDEN. DR.LEE DE FOREST.

Manager, H Gernsback Prussianizing the American Ether By H. GERNSBACK

on April 6, 1917, the Presi- apparatus appertaining thereto, and used tary of Commerce as provided by the WHEN,dent of the United States, by ex- for no other purpose except as a tech- act to regulate radio, approved Au- ecutive order, closed all wireless nical and training school stat'on." gust 13, 1912. stations, the order was carried out Here the similarity ends. In all other to the letter by all Radio amateurs In other words, a technical training school respects the three bills read actually and williugly and cheerfully. No notice has station is an experiment station and vice almost entirely word for word the same. come, to our attention where an amateur versa. Of course, this statement alone, un- We heartily approve Mr. Padgett's bill, disobeyed the President's wishes. less modified means that if the bill is actu- which also has the approval of the Presi- All amateurs stood solidly behind the ally past by both Houses the amateur will dent as admitted by the Navy Department. President when war was declared because be just as dead as that sensitive spot on a Now then, as Mr. Padgett's bill was in- all realized that everyoiie had to bear galena detector after it was hit by lightning. troduced on April 9, 1917, and as Mr. great sacrifices willingly and cheerfully. A second reading of the Navy Depart- Alexander's bill was introduced on Novem- When the armistice was finally signed, the ment's statement also informs us that the ber 21, 1918, one and one-half years later,

whole world breathed a sigh of relief, in- President approved a similar bill : H.R. and inasmuch as Mr. Alexander's bill reads cluding the American amateur who had been 2?73. exactly alike word for word all the way given to understand that as soon as peace We now turn our attention to this bill thru with the exception of the paragraphs was actually declared the ether would mentioning amateurs, Mr. Alexander be free for all once more. The ama- necessarily must have copied Mr. teurs were satisfied to go back to Padgett's bill. But when he came to pre-war conditions, to take up their the paragraphs mentioning amateurs studies in an art which has few paral- he ran his blue pencil right over them. lels as far as instruction and en- NAVY DEPARTMENT And that is the joker. President nobling of the mind is concerned. NAVAL COMMUNICATION SERVICE Wilson approves of Mr. Padgett's OFFioe or THE DinccTon Unfortunately, however, in certain bill favoring amateurs. Mr. Alex-

quarters in Washington, a feelinj; WAiHrNotw,. Rovember £3. 1916 ander with the stroke of his pen, seems to exist that the amateur al or was it the blue pencil?—wants best is a nuisance and should be done to shut out the amateur from the away with entirely. On November ether forever. 21st two identical bills were intro- Not that Mr. Alexander is not fa-

duced, Senate 5036 and H. R. 13159, ID ,epl/ to year request of DoTeoOer S2. I9m for miliar with the amateurs. He knows Fletcher, the luforiAllon relative to reopenloe aaateox radio atetlons, you, well. the former by Senator are Informed tiif.t as all radio alotlona not necessary to the them For Mr. Alexander was latter by the Honorable Joshua W. Al- OoeemiQcrit uf the LUlted jtatea >vere cloBod for the duration the author of the original radio bill of the uer by un SzeoutlTe Order dated April 6. 1917, no fur* exander. These bills are reproduced ther aotlon -nil be tai:eii regardiag thaae atatlosB oatll peace before it was a law. The writer in nae^seen declared by the Prealdent. elsewhere in tiiis issue, as well as a 1912, as will be remembered by most v<:Ty r.--3pecifully. statement given out by the Navy De- amateurs, fought the Alexander bill partment. The Navy Department for the reason that it did not make frankly admits that these bills are not mention of the amateurs. Finally Mr. a war measure and it also endorses Alexander and his committee became Co;amajider. i. .lavy these bills. The Navy Department Aeeietant Director naval CoTiaianicatloiie convinced that it would be an injus- also makes the extraordinan.* state- tice to silence the amateurs, and in eleotriuui experl-nenter ment that "experimenters" and sci- tS3 Tuiton Street. April of that year the Alexander entists will not be ''interfered with, re» Tor* B T Wireless Bill amended appeared. As will also be remembered, Mr. Alexan- IT SHOULD BE NOTED der and his advisers accepted the THAT THIS BILL IS NOT TO writer's recommendation pertaining CREATE A COMPLETE GOV- to amateurs as set forth in the ERNMENT MONOPOLY. THE writer's editorial in the February, SCIENTIST, MANUFACTURER, 1912 issue of Modern Electrics, and AND SHIP OWNER ARE SPE- this bill later in the year was signed CIALLY PROVIDED FOR, AND by President Taft, thus making it the NO CHANGE IS PROPOSED present wireless law. IN THEIR STATUS UNDER It strikes us as remarkable that in- EXISTING LAW. STATIONS MAY and read it carefully. We are struck with asmuch as in 1912 Mr. Alexander could not BE LICENSED FOR SPECIAL COM- the fact that it was first introduced in the see the amateurs with an ultra-microscope, MUNICATION, AND THESE ARE House of Representatives by Mr. Padgett his eyesight as far as the amateur is con- EXEMPTED FROM GOVERNMENT under date of April 9, 1917, a year and a cerned has not grown better in 1918. As soon OPERATION. half before Messrs. Alexander and Fletcher as we knew that there was to be a new wire- Any intelligent person reading this para- introduced their bills. Strange to say, all less measure, we got busy immediately and graph must come to the conclusion that the three bills read alike except that Mr. we found out that there will be a hearing amateurs would revert to their ante betlum Padgett's bill right after the fifth para- of Mr. Alexander's bill on December 12th days the minute peace was declared by graph, referring to the technical and train- which will continue from day to day until Presidential proclamation. ing school stations, has the following: all have had a chance to be heard. Inas- So far, so good. We now turn to the The term "Amateur" station much as this issue of the Electrical Ex- Alexander and Fletcher identical bills, and means any station not an experiment perimenter does not come out until about read them attentively. To our amazement station or a techniccd and training the 12th of the month, it would have been not a word is mentioned about the amateur. school station and not operated for impossible to inform all amateurs of the This bill also contains the extraordinary financial profit. impending measures, and for this reason statement that We also find in this bill, under Section 3, we took it upon ourselves to mail out at the following: once some 50,000 letters broadcast to all "Experiment station means a radio This section shall not apply to ex- amateurs giving them the facts of the case. station actually used for conducting experiment stations, technical and Of course it is not too late even now for periments for the development of the training school stations and amateur those who have not received our letter. science of radio communication or the stations, duly licensed by the Secre- Mr. Alexander's bill has not as yet been January. 1919 ELECTRICAL EXPERIMENTER 625

ernmental operation of these stations. Trans- past, and doubt much if it will. or wire to Mr. Alexander's committee at we veo' oceanic radioteiegraphy is not a serious competi- What wc want is Mr. Padgett's clauses once. When you write refer to H.R. tor of the cables. High-power stations are not reinstated—in other words, what we want 13159 and address your letter to the yet able to receive from one another all day in all seasons, cable communication is secret, while are concerned is Honorable W. Alexander, House of as far as the amateurs J. signals from radio stations are transmitted in all the passing of the bill H.R.2573, which Representatives, U. S. Committee on directions, and al! nations can read the business has the full approval of the President, The Merchant Marine and Fisheries, of all others. Only the most carefully devised Department; Washington, D. C. codes can make radio traffic secret, and experts so admitted by the Navy will not admit that any code or cipher cannot be or, what amounts to the same thing we broken in time. Signals from high-power sta- want Mr. Padgett's clauses regarding A BILL TO FURTHER REGULATE tions become international matter at once. Even an ordinary shore station tran- in Alexander's RADIO COMMUNICATION. the signals of amateurs inserted Mr. scend the three-mile limit and arc capable of in- bill. One is exactly the same as the Statement by the Navy Department. terfering with the legitimate work of an installa- This bill was introduced by Senator Fletcher, other. This is all that we want, and it tion under a foreign flag. Only by the most care- Chairman of the Senate Committee on Commerce, ful regulation of radio traffic, tnrough interna- It is fair to all concerned. simply means and by Judge Alexander, Chairman of the House tional agreement, can the maximum good be ob- that the present wireless law is to re- Committee on the Merchant Marine and Fisher- tained, and only by each nation having the opera- ies, on November 21, 1018 (S. 5036 and H. R. main the same, and this, we are cer- tion of radio stations under its direct control can 13159). A similar bill (H. R. 2573) has had the international agreements be properly executed. tain, will satisfy every amateur in the direct approval of the President, and the princi- In spite of the claims of inventors, radio com- ples contained in the bill have the approval of country. munciation is still hampered by atmospheric dis- practically all of the executive departments, as licensing system whereby the ama- turbances commonly termed "static" and by in- The shown in the previous hearings before the House congested districts, as in the case teur was licensed by the Department of Committee on the Merchant Marine and Fisher- terference. In of important seaports, communication is limited five during ies. Commerce for the years which and must be controlled by a central organization, In general, the bill provides for the acquisition the law was in force, proved satisfactory otherwise a serious situation ensues. In the case and operation, by the Navv Department, of all of high-power stations where there is a limit to to all concerned. No amateur has ever radio stations on shore usea for commercial pur- the nuraoer of long wave lengths which can be and as the stations were poses. Irrespective of the general subject of harmed anyone, used, interference is encountered regardless of government ownership, this principle is clearly the amateurs refrained from send- between stations. For instance, a licensed indicated as necessary in the case of this par- the distance station in Washington is liable to be interfered ing out false calls or otherwise making a ticular public utility. Since the early days of the with by a station in San Francisco, while at- use of radioteiegraphy many companies have nuisance of themselves, a condition which France or Italy. operate radio stations as a commercial tempting to receive from prevailed before the 1912 wireless law was tried to enterprise in the United States generally, or in IT SHOULD BE NOTED THAT THIS BILL IS past. certain localities. Except in very special circum- NOT TO CREATE A COMPLETE GOVERN- It has been proved time and again that stances, these enterprises have tailed to make an THE SCIENTIST, MANU- adequate return, and in most cases no profit has MENT MONOPOLY. radio apparatus enormously sharpen the FACTURER, AND SHIP OWNER ARE ESPE- been made except through the sale of ttock. The CIALLY PROVIDED FOR, AND NO CHANGE senses of a young man by making him reason for this is that a complete monopoly is IS PROPOSED IN THEIR STATUS UNDER EX- keener all the way around, besides teach- necessary. That is, all stations must belong to ISTING LAW. STATIONS MAY BE LICENSED one system. A period of about 18 years has art that is worth while. THESE ing him an clearly demonstrated that the United States Gov- FOR SPECIAL COMMUNICATION, AND Hundreds of thousands of radio amateurs ARE EXEMPTED FROM GOVERNMENT OP- ernment is the only concern able to obtain and ERATION. in the Signal Corps have helped towards maintain such a monopoly, although many attempts have been made. winning the war, and they will do so again agreement with the Department of Com- The first law regulating radio stations was en- By merce, the licensing of stations above mentioned, when called upon. If it had not been for acted in 1912. At that time Congress recognized licensing of ship stations and of commercial the fact that a complete system of radio stations the wireless, the United States would not have for be transferred to the having been established by the Navy Department operators them would such large body of telegraphers at Depaicment, since naval operation of com- had a for the national defense, the maximum public Navy mercial shore stations would eliminate a number the outset of the war, and nearly all of good could be obtained from them if they were the duties assigned to the Secretary of Com- permitted to assist commerce by handling the of these volunteered. Furthermore, radio merce. radio business of merchant ships. A certain num- the great to is not a measure. In accordance with telegraphy has been cause keep ber of naval radio stations were authorized to This war all United the young man away from questionable handle commercial business. This business has the Act of 1913, radio stations in the possessions, which were not already been successfully handled for four years. The States and company during his spare evenings, and in the Government's hands, were taken over by Navy Department has demonstrated its ability to criticism that Department as a war measure, and are this alone overbalances any handle smoothly and efficiently, wherever permit- the Navy now being operated by that Department, prompt- could possibly be brought against the do so, all communication between ship and ted to changes have occurred shore, without any restrictions on the nationality ly in April, 1917. Many amateur. Any parent who has a growing during tne war. Stations formerly operated com- of the ship or the ownership of the radio set on son is thankful for being allowed to spend mercially have been found to be unnecessary for board, ana (juite irrespective of the ownership of either commercial or war purposes. On account all he possibly can for radio apparatus be- the connecting land lines and cables to which the menace the necessity for in- radiog:rams were delivered for further transmis- of the submarine cause he realizes more than anyone else stant control of troop convoys, and the sudden sion if originating at sea, or from which traffic that it keeps together the home ties between rise in importance of transatlantic communica- was received if destined seaward. The Navy De- tion for naval and military purposes, a few addi- son and home. partment is now prepared and desires to handle tional stations and some special arrangements all commercial work of all stations. It is not too late as yet to protest necessary on the Atlantic coast. The busi- The part played by high-power stations in this were against Mr. Alexander's bill, and those war and before the United States became a party who have not as yet done so should write to it, shows very clearly the necessity for Gov- {Continued on page 665) Radio Law and Existing Restrictions By WILLIAM B. DUCK

The following interesting article by the states. Consequently when Congress receiving station or for a transmitting sta- an attorney well versed in the subject, enacts any law, it must find its authority in tion with a range within the limits of the should answer the thousands of letters some provision in the constitution. For state where located. If Congress had at- with which we, as well as all amateur instance Congress cannot pass any law regu- tempted to exercise jurisdiction over these Radio Supply Houses have been bom- lating the rates of railroads both terminals stations the entire law would have been un- barded since Nov. lUh of this year.— of which are within the borders of the same constitutional. Editor. state. The state only has such authority. When the United States entered the wireless amateurs never had Our supreme court has given a very wide world war, the president, on April 6th, 1917, MANYvery clear notions concerning the interpretation to the interstate commerce as Commander in Chief of the Army and regulations of Congress upon clause of our constitution. It has declared, Navy, ordered all the wireless stations dis- wireless sets, and fewer yet for instance, that communication carried on mantled. The existence of a previous law grasped the legal effect of the ex- by line wires extending from one state into on this subject in no way added to his isting restrictions upon the use of such another may be regulated by it. No wire- power to order the stations closed. It was apparatus. less amateur has ever bothered to go to the a military act, and its authority was founded The existing vjdreless law derives its au- expense of having the courts pass upon the on recognized law on this subject, which it thority and likewise its legality from the so- question as to whether Congress has the is unnecessary to discuss here. It will be called interstate commerce clause of our power to license a transmitting station for observed that the order of the president national constitution, giving to Congress the exclusive use between two cities in the embraced all wireless equipment, both trans- right to regulate commerce among the sev- same state, if as an incident to this com- mitting and receiving. The moment peace eral states. Were it not for this provision munication, the station may be heard be- is declared, all amateurs will "ipso facto," in our constitution, Congress never would yond the borders of the state. In fact it is without promulgation of any decree by have had any authority to legislate upon any better for the amateurs that Congress com- the president or any one else, have the phase of this subject. Our national consti- pels the high power amateur stations to sub- right to use their receiving sets and small tution embodies a wide variety of powers mit to its decrees in the regulation of their power transmitting sets whose range given up by the thirteen sovereign states stations. does not extend beyond the border of when the constitution was adopted. All It is for this reason that the wireless law the state. A great many other war other powers and rights were reserved by provides that no license is necessary for a powers will likewise cease at this time. 626 ELECTRICAL EXPERIMENTER January, 1919 Experimental Physics

By JOHN J. FURIA, A. B., M. A., (Columbia University) LESSON EIGHTEEN

Conduction of Electricity Thru Gases. charge in that the former is the passage and hence form shadows when striking an the air included, under nor- of electricity from one point in a gas to obstruction. In figfure 95A c is the cathode. GASES,mal conditions will not conduct another point and the latter is the passing A piece of metal hinged at its lower end electricity. However, when a high of a gas from a point into the surrounding stands in the path of the rays. A distinct potential is establisht between two gas. As more current is past thru the shadow of the same shape as this obstruct- points in a gas, as for example primary of the spark coil a higher potential ing metal is formed at the end of the tube. is terminals when a Wimshurst Machine is excited or a developed at the secondary and On dropping the metal down at the hinge spark coil operated, the gas offers less and therefore a longer spark is produced, i. e., by shaking the tube the shadow disappears. the length of the spark is proportional to Experiment 106 the potential ; a one inch spark being pro- In figure 95B the cathode is concave and duced by a potential of about 30,000 volts. spherical. The other electrode (anode) Experiment 104 A straight glass tube about an inch and a half in diameter and fifteen inches long has platinum electrodes attached to aluminum discs. An air pump is connected at the opening a. The electrodes are connected to the secondary of a spark coil and also to the spark gap in figure 94, the gap being smaller than the rated spark of the coil. If the coil is now operated, a spark passes thru the gap g and nothing is observed in the tube. As the air in the tube is gradually exhausted by the pump the For the Production of Concentrated X-Ray«, Fig. 95-A. Vacuum Tube for Demonstrating spark thru the gap disappears and a dis- a Special Form of Focus Tube Is Used. Ca- That Cathode Rays Cast a Shadow. The charge is seen thru the tube which is neither thode Rays Coming from the Concave Elec- Travel In Straight Lines, as the Metal Rays trode at Left, Converge and Strike Platinum and Its Shadow Prove. spark nor brush. It will have the appear- Cross TargM at Right, Where X-Rays Are ance of a ribbon of crimson light. The Generated. less resistance as the potential is increased discharge then broadens out into a bluish, consists of a small piece of very thin sheet and finally electricit>' is discharge' 1 between fuzzy column. When the pressure reaches the two points. The subject of the con- about five-tenths of a millimeter of mer- platinum. The cathode rays are converged, duction or the discharge of electricity thru cury, the negative electrode (cathode) be- focus on the platinum and are therefore incan- gases with its causes, effects and results is comes covered with a thin luminous layer. very concentrated. The platinum a vastly important one. It has attracted the Next to this we find a dark space known as desces, showing the heating effect of the attention of the foremost Physicists and Crookes' dark space, next to which is a cathode rays. Of far greater importance or has given rise to modern Physics with all luminous part called the negative glow, and than either the fluorescent, the shadow, is the magnetic effect, its information regarding the electron. beyond this a second dark region known as the heating effect especially as this gives us an insight Experiment 103 into the nature of the cathode rays. Attach the terminals of a spark Experiment 107. coil to a pair of combs consisting of several needle points and keep In figure 96 a-b is a fluorescent the pair separated by a distance sev- screen of zinc sulfid, or barium eral times greater than the rated platino-cyanid ; c is a mica strip spark length of the coil. Darken with a narrow slit in it. The the room and a glow will be ob- cadiode rays emerging at d are ab- served surrounding the points. If sorbed by the mica c, except for a small part passing thru the slit. more current is supplied to the coil Fig. 96. Deflection of Cathode Rays by a Magnet, The straight thru for the so that a higher voltage is devel- Screen a -b I* of Fluorescent Material, So a* to Make th e Ray* These travel VIdbla. oped, the glow will increase in size full length of the tube and cause a screen a-b to and intensity. This glow is tech- narrow band of the of nically known as a brush discharge or cor- the Faraday dark space. From this space fluoresce brilliantly. Hence, the path ona, see Fig. 93-A. Now bring the termin- to the positive electrode we have the lumi- the rays, which are themselves inxnsible, als of the spark coil close togetJier. A spark nous positive column. By adjusting the is readily seen. If now a horseshoe mag- are jumps across the gap in a straight line path. pressure slightly the positive column can net is brought near the tube the rays to the See Fig. 93-B. As the terminals are gradu- be made to divide up into a series of deflected toward it at right angles is precisely ally separated the spark passes thru an ir- luminous and non-luminous spaces called magnetic field. This what rays con- regular path until finally the limit of the coil striae. (Geissler tubes are partially evacu- would happen if the cathode bent into fancy shapes and sur- is reached and no spark passes. The spark ated tubes (Continued on page 670) discharge then differs from the brush dis- rounded with jackets containing colored liquids to produce pretty color effects.) If the pressure is lowered still further, to about 1/100 part of a millimeter, the column will gradually disappear and the walls of the tube will begin to fluoresce, the fluorescing color depending on the nature of the glass. This fluorescence is produced by streams of small particles issuing from the cathode and we consequently call them cathode rays. This fluorescent property of cathode rays is useful as a means of detection and observation of the rays. Glass is not the only substance to fluoresce under the bombardment of cathode rays. Calspar, barium platino-cyanid, potassium cyanid, yttrium and thorium also fluoresce. A Variable Vacuum Tube Experiment with a Experiment 105 Spark Coll. As the Vacuum Increases an Fig. 97-B. Typical X-Ray View of the Hand, Electrical Discharge Begins to Take Placa Showing Rings on the Finger. Cathode rays travel in straight lines Within the Tube. —

January, 1919 ELECTRICAL EXPERIMENTER 627

The Effect of Statics on Wireless Transmission By NIKOLA TESLA Written for the ELECTRICAL EXPERIMENTER

FEW statements regarding these sisted of a transmitter comprising a pri- nature of the effects, are making install- phenomena, in response to a request mary circuit excited from an alternator or ments so defective in construction and of the Electrical Experimenter, equivalent source of electrical energy and mode of operation as to preclude the pos- A'may be useful at the present time a high potential secondary resonant circuit. sibility of the great realization which might in view of the in- be brought within creasing interest and easy reach by proper importance of the application of the subject. underlying principles The commercial and one of which application of the the most desirable at art has led to the present— is the com- construction of larg- plete elimination of er transmitters and all static and other multiplication of interference. their number, great- During the past er distances had to few years several be covered and it emphatic announce- became imperative to ments have been employ receiving de- made that a perfect vices of ever increas- solution of this ing sensitiveness. All problem had been these and other discovered, but it changes have co- was manifest from operated in empha- a casual perusal of sizing the trouble these publications and seriously im- that the experts pairing the reliability were ignoring cer- and value of the tain truths of vital plants. To such a bearing on the ques- degree has this been tion, and so long as the case that con- this was the case servative business no such claim could men and financiers be substantiated. I have come to look achieved early suc- upon this method of cess by keeping the.' Tesla's Static Eliminator, Patented and Used by Him over Twenty Years Ago. It Will intelli- Be conveying Fully Described In an Early Issue of the Electrical Experimenter steadily in mind anu gence as one offer- applying my efforts ing but very limited from the outset in possibihties, and the Government has deern- connected with its terminals to ground and the right and correct scientific direction. ed it advisable to assume control. This to an elevated capacity, and a similar tuned I may contribute to the clearness of the unfortunate state of affairs, fatal to enlist- receiving circuit including the operative de- subject in answering a question which I ment of capital and healthful competitive vice. On that occasion I exprest myself have been asked by the Editors of the development, could have been avoided had confidently on the feasibility of flashing in Electrical Experimenter with reference to electricians not remained to this day under this manner not only signals to any ter- the report contained in the last issue, that the spell of a delusive theory and had the restrial distance but transmitting power in signals had been received around the globe, practical exploiters of this advance not per- unlimited amounts for all sorts of industrial an achievement the practicability of which mitted enterprise to outrun technical com- purposes. The discoveries made and experi- I have fully demonstrated by experiment petence. mental results attained I made with a wire- eighteen years ago. With the publication of Dr. Heinrich less power-plant erected in 1899, some of The question is, how can Hertz waves Hertz's classical researches it was an ob- which were disclosed in the Century Maga- be conveyed to such a distance in view of vious inference that the dark rays investi- zine of June, 1900, and several U. S. patents the curvature of the earth ? A few words will gated by him could be used for signalling subsequently granted to me have, I believe, be sufficient to show the absurdity of the purposes, as those of light in heliography, borne-out strikingly my foresight. In the prevailing opinion propounded in text books. and the first steps in this direction were meantime the Hertzian arrangements were We are lining on a conducting globe sur- made with his apparatus which, in 1896, gradually modified, one feature after an- rounded by a thin layer of insulating air, was found capable of actuating receivers other being abandoned, so that now not a above which is a rarefied and conducting at a distance of a few miles. Three years vestige of them can be found and my atmosphere. If the earth is represented Dy prior to this, however, in lectures before system of four tuned circuits has been uni- a sphere of 12^" radius, then the layer the Franklin Institute and National Elec- versally adopted, not only in its funda- which may be considered insulating for high tric Light Association, I had described a mentals but in every detail as the "quench- frequency currents of great tension is less wireless system radically opposite to the ed sparks", "ticker", "tone wheel", high fre- than 1/64 of an inch thick. It is held that Hertzian in principle inasmuch as it de- quency and rotating field alternators, forms the Hertz waves, emanating from a trans- pended on currents conducted thru the of discharges and mercury breaks, fre- mitter, get to the distant receiver by suc- earth instead of on radiations propagated quency changers, coils, condensers, regu- cessive reflections. The utter impossibility thru the atmosphere, presumably in straight lating methods and devices, etc. This fact of this will be evident when it is shown by lines. would give me supreme satisfaction were a simple calculation that the amount of The apparatus then outlined by me con- it not that the engineers, misinterpreting the (Continued on page 658) 628 ELECTRICAL EXPERIMENTER January, 1919

res- GERMANS USE BICYCLE DYNAMO electricity which can be used for radio or base-pipe connects with a comprest-air filled by an air- TO OPERATE RADIO SET. lighting purposes, etc. In fact, this scheme ervoir which is always kept The accompanjnng illustration shows an is not new to the American wireless ama- pump. turn the comprest air ingenious German method of generating the teur, for we published an article on such a The operators on device for produc- lever. Air from the tank rushes to the ing current to top of the innermost pipe and pushes up operate a wireless on it with a force upward of twenty-five transmitter several pounds for every square inch of its sur- years ago. A per- face. The sections shoot upward, one after son sitting on a another. bicycle fitted with proper gearing, ex- Of the 8,000 girls who applied for service with the erts a great deal as military telephone operators more power than American forces abroad 650 were accepted. would be imagined off hand, and besides for warfare requirements the outfit is noiseless, albeit it is not quite so handy as the small gasoline engine outfits used by some of the other armies. NEW TELE- SCOPING RADIO TOWER. A device that promises to be of great importance to the field wireless Cefliral News Photo aemce (i*\ service is a tele- The Above Illustration Shows an Ingenious German Method of Generating Electricity for a Wireless Installation In the Trenches, scopic tower that Captured in a British Advance. A tandem bicycle with Its Wheels can be rasied al- Removed Has Been Fixt to the Ground, and the Pedal Wheels most instantly on Connected by Belting with a Small Dynamo. the throwing of a lever. This tower, necessary electric current for operating a the invention of R. W. Dean, of Des radio installation in the trenches, which was Plaines, Illinois, has been presented to the captured in a recent British advance. As Government, says The Oscillator. the photograph shows, a tandem bicycle The tower that carries the wireless aerial with its wheels removed has been fitted with works on an extremely simple principle. A a supporting frame so as to stand upright number of light steel pipes fit inside of No Wonder the Naval Radio Students at and the pedal wheels connect with a belt to one another, the space between them being "Harvard" Get a Headache Now and Then. Excuse Him, Foiku, if He Don't Write Every small made air-tight by a series of washers at a dynamo. Day. The Boy Is Busy! What?—Courtesy Such an outfit will produce considerable the top of each but the middle pipe. The the "Oscillator." Marconi Company Claims Famous ((IStatic Preventer" Discovery

"With the conditions that pledged us to the ether sometimes made the wireless sig- ficial 'Peace' is declared," said Mr. Wea- absolute secrecy no longer prevailing, the nals so indistinct that they could not be gant, "I will present a technical paper be- Marconi Wireless Telegraph Company of understood, or drowned the weaker trans- fore the Institute of Radio Engineers, America is permitted to announce a dis- mission entirely. The Weagant system, describing the invention. Also a body of covery and invention in wireless telegraphy based on a unique selective principle, technical men will be invited to one of our that will mark a new era in world commu- eliminates 'interference' and permits abso- stations to hear it work." nication," says a statement issued by Ed- lutely clear communication, regardless of the stations in the ward J. Nally, Vice-President and General operation of other even SHIPS PERMITTED TO USE RADIO Manager of the Marconi Wireless Tele- immediate vicinity. AGAIN. graph Company of America. "The notable contribution to wireless Announcement has been made by the "Ever since the genius of Marconi made telegraphy opened by Mr. Weagant's dis- Naval Communication Service that com- wireless telegraphy a fact, the only limi- covery makes continuous wireless communi- mercial wireless traffic between United tation of this method of communication cation over the oceans and between conti- States merchant vessels and naval radio was the deadly phenomena of 'static con- nents an absolutely assured fact for twen- shore stations would be resumed at once. ditions.' ty-four hours of the day and at every sea- This means that wireless messages may "It remained for an American radio ex- son of the year, regardless of atmospheric be sent to passengers on board steamships pert, Roy A. Weagant, Chief Engineer of conditions. All the Marconi high power and that travelers at sea may communicate the Marconi Wireless Telegraph Company stations are being equipt with the Weagant with shore. of America, to discover the solution of the system, and the stations of the Pan-Ameri- During the war steamships were forbid- static problem. can Wireless Telegraph and Telephone den to use their wireless except to listen, "Among the revolutionary changes that Company, which are to link North and the precaution being taken to prevent sub- the new system effects in wireless instal- South America, will likewise be equipt." marines and surface raiders from learning lations will be the immediate disappearance This invention sounds almost too good of the positions of Allied vessels. of^ the huge steel towers, heretofore built to be true. However, Mr. Weagant, in an at great heights to catch the incoming wire- interview with the Electrical Experi- OCTOBER MEETING OF INSTI- less waves. Equipt with the Weagant in- menter's representative, stated that by very TUTE OF RADIO ENGINEERS. vention, the wireless receiving antenna are careful study of the subject over a consid- The Institute of Radio Engineers held a stretched merely a few feet above the erable period, discovery of an entirely new meeting on the evening of Wednesday, Oc- ground. basic principle had been made, and by acci- tober 9, 1918, in the Engineering Societies "Heretofore, also, the increasing number dent at that. It was not expected, but Building, New York. of high power stations that were being while making investigations along other A paper on "SPECIAL HEATING EF- «rected in every part of the world raised lines this particular effect became more FECTS OF RADIO FREQUENCY CUR- the difficult question of 'interference.' and more noticeable until it developed into RENTS," by PROF. EDWIN F. NORTH- Crossing wireless messages that shot thru a full-fledged invention. "As soon as of- RUP of Princeton University was given. January, 1919 ELECTRICAL EXPERIMENTER 629

Radiotelephone Guided U. S. Flyers Many Miles Away

SQUADRONS of American airplanes greatly resembles an ordinary incandescent which is capable of generating oscillations righting in France up to the moment lamp. This bulb contains two additional by a re-action between two or more tuned of the armistice, were maneuvering elements besides the usual incandescent fila- circuits, so that either damped or undamped under the vocal orders of the squad- ment, which are known as the plate and oscillations can be interpreted. ron commander that reached each grid respectively. In these oscillions, the Fig. 1 of the accompanying views shows pilot by radiotelephone. grid consists of a spiral winding of very a complete airplane Radiophone oscillation News of the successful development of fine tungsten or other wire wound upon a transmitter, especially designed for military glass frame, and so placed as to entirely surround but not touch the filament. The plates, of which there are two, are placed one on each side of the filament, outside of, but not in contact with, the grid. In operation, the oscillion or vacuum bulb, oscillation generator requires two sources of potential, one of low voltage for lighting the filament, and one of high potential for supplying current from plate to filament ^mahIP^^h across the vacuous space within the tube. ( A small motor-generator suitably wound to supply the proper voltage is generally

5. Oscillion Bulb Fig. High Power Radio- Fig. 4. New Vacuum Tube Control Cabinet. telegraph Transmitter. the The Meter At 110 Volt Direct Current is Frequently Used Left of the Panel Is a Hot-Wire "Radiation On These Sets for the Wing Circuit, Using a Indicator. Current" Suitable Potentiometer in the Circuit.

this device, hitherto a military secret, tho use. In this set the weight has been re- some inkling of it had reached the Germans duced to a minimum. A special chopper or just before hostilities ceased, was made calling key is fitted to the instrument as public recently by John R. Ryan, Director well as a special type of microphone for of Aircraft Production. modulating the oscillations in the form of Fig. "There are some details concerning it 2. New Combination Audion, Ultra- speech waves. At the left of the photo- Audion and One-Step Amplifier Designed By graph will be observed small re- which we cannot discuss yet," Mr. Ryan de Forest. a dynamo said, "but the radio devices worked out sembling an airplane bomb, one end of during months of experiment went into which is fitted with a small size propeller. actual service some weeks ago. I have employed as the most convenient source of This dynamo is driven by the force of the myself, standing on the ground, given or- current. Reception of radio-telephonic or air turning the propeller, as the airplane ders to a squadron flying in the air and telegraphic waves is accomplisht by the use speeds along, and thus current is produced watched them maneuver accordingly. of a similar but smaller sized vacuum bulb. for the operation of the oscillion. The "The transmission of the voice large oscillion bulb is enclosed in is clear enough to be heard dis- a wire cage to protect it from tinctly thru the sound of the air- breakage, and the necessary plane motor. It is in every way measuring instruments are the most satisfactory means of mounted on the front of the

communicating between 'planes panel, viz : a hot wire ammeter in the air and from the ground in series with the antenna circuit to 'planes." to measure the radiation current, The distance over which the a milli-ammeter indicating the radiotelephone talks from earth "B" battery current, and a fila- to 'plane is a matter of several ment battery ammeter. Suitable miles. tuning inductance and capacity "For some months," said Wil- control knobs are mounted on liam C. Potter, of the Equip- the front of the panel. The con- ment Division of the Bureau, "it nections between the various has been possible in our offices parts of the apparata are accom- in Washington to hear the plisht with flexible twin conduc- 'planes flying miles over the city, tors sewn in leather straps, the talking to each other and to the ends of which are provided with ground as they worked out and separable jack plugs. perfected the device." The illustration in Fig. 2 The accompanying views show shows a combination audion, ul- several new wireless telephone tra-audion and one-step ampli- apparata which can also be used fier. This combination is similar for wireless telegraphic trans- to the audion two-step amplifier mission when desired and utiliz- outfit, with the exception that ing the De Forest Oscillion bulb, the apparatus is arranged for having a filament, grid and wing. one-step amplification. This set The oscillion comprises an ex- will meet conditions perfectly, it hausted glass tube or bulb, the is claimed, where the intensity Fig. 1. Complete Airplane Radiophone Oscillation Transmitter of the normal signals does not size of which depends upon the Wind-Driven Propeller Fitted With Self-Excltlng Generator of the (Continued on output in watts, and which Type (Left), "Chopper" Calling Key and Oscillion Bulb In Guard. page 651) 630 ELECTRICAL EXPERIMENTER January. 1919 The Manufacture of Vacuum Detectors By 0. B. MOOREHEAD

ALTHO the majority of radio engineers maximum sensitiveness when used in con- successfully closes the pores of the metal. J^^ are familiar with the use and opera- junction with the aluminum plate and cop- The exhaustion of the tubes is the most tion of vacuum tube detectors, a brief per grid. In the selection of the glass to important operation because of the fact description of their manufacture may be in- be used, the devitrification of the glass had that the low vacuum of the round bulb, teresting. In the early experimental work to be considered, as during exhaustion of nickel element audion which permits of gas on this tj-pe of device, we strove to produce the tubes it is necessary to subject them to conduction is not used in the tubular "elec- a detector which tron relay," would combine wherein all gas maximum operat- phenomena must AFTER VOUVE. •BEEN OUT AT AND YOU S-MN THE m:> wonder who's ing efficiency with AND ALL HIS WITH be eliminated. SEfl FOR A DEVIl. OF A KAISEK "RUNNIWG AROUND inexpensive manu- — AfVO To produce the LON& TIME AND, bunkin'Bunch YOUR 3EST GIRL NOW,— facture. The next WISH THE 3>0&G-OfY6. AND ALL THAT high vacuum nec- you' RE FED UP fl/YD SORE point considered essary, I have AND 5ICK OF IT ALU w/M{ WAS OVER was the production found that a Gaede of desirable con- mercury pump ca- ditions, i. e., tubes pable of producing that possest oscil- a vacuum of lating characteris- 0.00001 millimeter, tics, tubes that backed by a piston were exceptional pump, such as the detectors, and tubes Geryck type, is the that displayed both most satisfactory qualities, says O. method of evacua- B. Moorehead, in tion. a paper recently The manifold to presented before WHEN ALL OF A SUDPEN AND YOU GO WlbO WITH which the tubes to the Institute of Ra- VOU HEAR A GENERAL EXCirEMENT fir^D GET 411 OH ,doy?-!-? be exhausted are dio Engineers. The MESSAGE GOING OUT WORMED up — FOR IT TURNS it\gR--R-5-'R?«t attached and the OUT TO ^^ fliN'T third consideration AND COPY IT -PEACE TO £E KivE. ?>yi?» vacuum line con- was the production 3 necting the mani- of a device easily fold to the pumps, handled and shipt are preferably without disturbing made of large di- the adjustment of ameter tubing. A the elements and containerfilled with damaging the fila- pentoxid of phos- ments. phorus is connect- Tubes and bulbs ed in the vacuum of various shapes line between the and sizes were pump and the tried, using a gas- manifold. The eous medium manifold is con- one tained in an oven ranging from A Great Moment We All Experienced"— Not Many Moons Ago. This Self-explanatory millimeter to 0.025 Oscillation the Third, Comes From Over the Bounding Foam Via Wireless Operator H. B. heated by gas and millimeter of vac- Burney, of H. M. C. S. Stadacona. arranged so that uum, many mate- the tubes during rials being employ- exhaustion may be ed as elements. Various exhausts were a temperature near the point of softening heated to high temperatures. applied, but it was soon found that the and nearly all glasses, when maintained at The lead glass tubing, used as the con- employment of a gaseous medium intro- this temperature for any length of time, tainer for the elements in the tubular type duced considerable difficulty in the matter have a tendency to separate out into the detector, is obtained from the glass works of accurate reproduction of a desired result. cry'Stalline state. in lengths of 6 feet (2 m.) with an inside Gases at pressures ranging from one milli- There has been considerable discussion re- diameter of 0.875 inch (2.2 cm.) and a wall meter to 0.0013 millimeter were next ex- garding the elements in this type of device of 0.032 inch (0.7 mm.) thickness. This perimented with. and I may say that aluminum plates and tube is cut in lengths of about 6 inches I found that a tube containing a platinum copper grids were first selected on account (15 cm.) and one end is drawn down to a filament in an atmosphere of hydrogen, at of their electro-chemical relation to the point. Two stems are made of glass tub- pressures comparable with one millimeter, tungsten filament. Later, numerous other ing similar to those used in an incandes- gave fair results. Tungsten filaments were metals were tried under the same and cent lamp, one stem contains the grid and then tried in higher vacua as well as at the other conditions of exhaustion and showed two filament leads, and the other contains so-called "gaseous medium" pressure. It widely different operating characteristics. the plate connection and one filament lead. was immediately noticed that conditions The selection of metals for the elements After the wire is sealed into these stems, could be duplicated as soon as a vacua is very difficult, as a slight difference in they must be annealed very carefully. The above that which allowed a "gaseous med- either the copper or aluminum changes the annealing consists in allowing the tempera- ium" to exist, were obtained. Moreover, whole system of exhaust. For instance, ture to drop very slowly, since quickly tungsten was ideal as a filament not only copper and aluminum purchased from one cooled glass is subject to internal strains lot will because of its refractory qualities and low factory require a certain degree of which arise in the following manner : In volatility but also because it acts as a puri- applied temperature during the evacuation, rapid cooling, a low temperature is soon fying agent by attacking any traces of resid- while another factory lot of the same weight established at the surface and the outermost ual gases that may remain in the tube and and size will require an entirely different layer solidifies while the interior tends to forming compounds which are then volatil- exhaust. contract, thereby exerting a pressure on ized on the walls of the tubes. I have eliminated this variation to some the outer layer which is directed inwards. As the parts are small and complicated, extent by subjecting the aluminum plates This may cause the stem to crack. the glass is worked before the blowpipe, to a temperature of approximately 600 de- After the stems are annealed, the grid is after it has been brought into the form of crees Fahrenheit (315° C), immersing wound to the proper diameter and the fila- tubes by the glass works. This tubing is them in a saturated solution of cyanide of ment is clamped onto the two leads. The obtained by first blowing a bulb, then fusing potassium, and finally rinsing in alcohol. plate is mounted on the other stem and the an iron rod to a point diametrically opposite The copper is subjected to heat until it two stems are then connected together by the blowpipe and rapidly separating the two glows, when it combines with the oxygen means of the filament. Final adjustment points of attachment from each other. of the air to form a black, brittle oxid which of the plate and grid is then made. The Various grades of glass were' experi- breaks off in scales and exposes the under- spacing between the elements is not very mented with, and a mixture containing a lying metal which is of rose red color. It critical in this type of device, but it is best high percentage of lead and a small quan- is then placed in a current of moist air and to wind the grid to a large enough diam- tity' of silicic acid was found to be the eas- becomes covered with a layer of oxygen eter so that it will strike the plate rather iest to work and produced a detector of compounds, which remains very thin but {Continued on page 671) January. 1919 ELECTRICAL EXPERIMENTER 631 A Vertical Cabinet Type Coupler By JOSEPH H. KRAUS, Jr.

CABINET couplers, altho handsome is being wound and the nails will act as wound with No. 30 enamel wire. Leave a and efficient, are quite expensive, grips for the axle (Fig. 1). A crank is length of eight inches at one end and com- even if the amateur attempts to now fastened to one end of the axle and mence winding one-half inch from the end. make one himself. In the follow- the whole is suspended from two "Y" A tap of the loop variety (Fig. 3) is taken ing article is given a description of shaped uprights nailed to the opposite ends a large cabinet coupler which did remark- of a small box (Fig. 2). By using this cotton-waste method there is no necessity of fitting a rod tightly i.ito the tube and KC may be out m here if desired a lathe is not essential. The winding is now commenced three-fourths of an inch from one end of the tube and a tap eight inches long is taken off every turn for the first twenty turns. Number these starting with the first wire as No. 20, then 19, 18, Var Cond. 17 and so on down until we get No. 1, and then No. 0. These taps must not be taken off directly under each other, but they zig-zag or spiral one-third around the tube, so as not to allow the least chance for a short circuit between two turns. Each must be carefully insulated and No. 22 black enamel wire used. 1 Secondary Smtcn. The manner in which a tap is taken oS doesn't make much difference and every Amateur has a method of his own. How- ever, here are two "standard" methods. For the primary the preferred method is the to solder a wire to the place where Prim. Jtr tap is taken off and insulate it carefully. . • . Another method is to twist a loop into the wire and then continue winding; this will constitute a double wire lead (see Fig. 3). (This method will save trouble in the secondary winding.) O. After the twentieth tap has been taken . ^ Pr/m Dei off (No. 0) the wire is wound for twenty turns and then a tap taken off. In this until one-half inch Fig.J Arranoement of Vertical Coupler Secondary, way the tube is wound Showing Friction Held Drum on Which Cord Supporting the Secondary Is Wound. The Front View of Finished Panel of Vertical Tapi Are of Flexible Stranded Lead and Coupler Receiving Set. The Variable Coupler Cabled Together. Control Handle Is Placed in the Upper Right Corner of the Panel. able work and the cost was surprisingly low. An instrument such as this is an off every three-quarters of an inch of asset to any station and will well repay the winding. These loops are made one inch ambitious Radio Amateur for the time and long and are taken off spirally one-third trouble involved. way around the tube. As the winding pro- THE PRIMARY (WINDING WITHOUT A ceeds and as each tap is taken off a hole is LATHE) punched into the cardboard tube immediately under each tap and a match stick Two cardboard tubes are first procured, ' inserted into the opening; each respective eleven inches long by five and four and one- tap is to be drawn thru its particular open- half inches in diameter, respectively. ing. When complete there should be fif- The five inch diameter tube is first wound teen taps. Now to each of these is soldered in the following manner : In the center of a piece of flexible cotton or silk covered a rod of wood about two feet long and of a wire about twenty inches long, a piece of diameter that will easily pass into both the rubber tubing slipt over the joint and the five and four and one-half inch tubes (a wire drawn thru the center of the coil broomstick handle will do) drive several toward one end thru its respective opening. nails, in such a manner that their heads Number each tap in order, shellac and protrude about one-half inch from the allow to dry. wood. This wooden rod is then placed in Note : These wires are not soldered on the five inch primary tube and held as near until the tube has been fully wound and to the central axis as possible while cotton Detail of "Glass" Knob Switches Used On removed from the crank. waste is packed in around the axle. The Vertical Coupler Here Described. They Give (Continued on [mgc 671) friction of the cotton waste against the Very High Insulation Efficiency. tube will prevent it from slipping when it from the other end and one tap taken off every twenty turns. These may be taken off in a perpendicular line, as there is enough winding between each to prevent a short. Number the taps in order from one to fifteen. The wire if carefully wound will result in about thirty-six turns per linear inch, and wound for a little more than 854 inches, will net 320 turns, giving twenty taps of one turn each and fifteen taps of the twenty turn variety. Remove from crank and shellac well. THE SECONDARY The Cardboard Tube on Which the Wire Is to Be Wound Is Mounted on the Crank of Where No Lathe Is Available for Winding the Winding Rig by Stuffing Cotton Waste The secondary or four and one-half inch the Coll. Resort May Be Had to a Home-made Inside It. tube is now mounted in the same way and Winding Rig Like That Shown. ^ ! ;

632 ELECTRICAL EXPERIMENTER January, 1919

NEW "BUMBLE-BEE" HY-TONE SPAIN TO AMERICA BY AIR IS ANENT THAT RADIO COMPUTA- CODE PRACTISE SETI PROJECT IN MADRID. TION GRAPH. Here's the hy-tone code teaching outfit Captain Herrera, chief of the Spanish By K. N. Cummings, Asst. Engineer, you have been looking for, Radiobugs military air forces, has had a number of MarconiiViar W. T. Co., of Canada. interviews with King ITH regard to the article in Alfonso on the sub- your September issue, "A Graph Hi:i^ ject of an aerial postal for Solving Wave Length, Fre- and passenger service w quency, Inductance and Capacity," between Spain and the I would like to point out that all United States. The the commercial values of the quantities can scheme also has been be represented by use of the two squares of discust at Cabinet the published diagram bounded by the hues meetings and it is said representing one milli-henry, 0.1 milli-henry, that a leading shipping 10-* uf. and 10-' uf. (uf. = microfarad.) To company is willing to do this two inductance scales are required finance it. as in the diagram herewith. The plan, it is un- Each diagonal line represents two wave Microphone derstood, is to manu- lengths, one being ten times the other, as Battery facture large airships shown for 600-6,000 and 2,000-20,000 meters capable of carrying giving directly a range of 600 to 20,000 mre Cooe forty pasengers, be- meters, the left-hand inductance scale being sides the mails. The used for the lower range of wave length, rate charged for a the right-hand for the upper range. passenger, if the Only a part of the commercial waves scheme is carried out below 600 m. are obtainable directly, but will be $400, and let- values not on the chart can easily be obtained

ters will be charged as follows : To find, say, the inductance required for with 0.003 uf., note Pt7ones for at the rate of $1 300 m. .s— per hundred grams that the 0.003 uf. line intersects the 3,000 m. weight (about three line at 0.00084 h. Divided by 100 we ob- No Buzzer Gives a True Musical Note— But the Bumble-bee Doesl ounces and a half). tain 0.0000084 h., the required value. In Hence, Combine the Bee, a Fan to Waft, Periodically, an Aroma of It is estimated the general, using the line representing 10 times Hyacinth His Way, When We Have a Pure Musical Note Producer. journey take length, divide the value indicated The Microphone Carries His Tuneful Buzzlngs to Our Ears, Via the would the wave Telephone Receivers. two and a half days. by the graph by 100 and vice versa. Values of inductance and capacity not shown The set works as follows : The sending A BATTERY-LESS TELEGRAPH. directly may be used as follows: Suppose key (A) closes the circuit thru the bat- A simple telegraph set may be put up be- we wish to find the inductance required tery (B) and lamp (C). The light works tween two chums' houses by running a with a wave of 8,000 m. and capacity of relay the selenium cell (D), operating the small wire from house to house about 20 1.7 uf., which are approximate values of (E), which closes the circuit of the spe- feet above the ground and 50 feet from the Glace Bay transmitter primary; divide cially quick-starting and stopping motor the lighting wires in the street ; connecting the capacity by 1,000. The line for 1.7x10-' (M). A fan (F) on the shaft of this a key and receiver as shown in the follow- intersects the 8,000 m. line at about plant motor plays a breeze on the (H), ing diagram. No batteries will be needed. 1.06x10-' h. Dividing by the same number wafting an hyacinth to the un- Aroma de One wire is grounded to the gas or water by which we divided the capacity (1,000) (I), is tuned suspecting bumble-bee which we obtain 1.06x10-" h., the required value. to a clear hy-tone. The microphone picks ,Keij The procedure would be exactly similar up the bumble-bee's buzzes faithfully and -M with a known inductance and wave length. reproduces them in the telephone receivers. H-* By extension of the above procedure, Every time you press the key it buzzes. s which is simply based on the fact that Voila ! Contributed by Ga Gb wave length varies as the square of the \VM. E. R. MIDDLETON. capacity or of the inductance, as the case may be, and that the product of capacity WIRELESS MESSAGES REACH and inductance is constant for any par- CAL., ARCADIA, FROM Phone Phone ticular wave length, we can obtain any BROOKLYN YARD. wave length, inductance and capacity, but System. It Oper- The wireless station at Arcadia, Cal., by A Batteryless Telegraph required which are not ates by Induction from a Nearby A. C. Light- if many values are using for an aerial the cable of a balloon, put ing Circuit. on the chart, it would be better to construct aloft from the training field, has intercepted another pair of squares of the original messages sent by the Brooklyn Navy Yard pipe. It works by induction from the light- graph from which the values could be read wireless station, according to an announce- ing circuit. directly. The advantage of this graph oyer ment the I. MILLER. by War Department. This bal- Contributed by RAY the original one is its increased scale, which [Where no lighting line is in the neighborhood, loon cable probably makes the highest aerial times that of the original for the bury a zinc plate in moist earth at G, and a cop- is ten in the world. con- per plate at G^. This system was once used by same size paper. It is also easier to This announcement was the made by the editor, and by using a 75 ohm receiver at struct, the number of logarithmic lines Division of Military Aeronautics, indicat- each station, satisfactory results were had over Yt required being but 3/17 of the number mile. This "ground battery" gives about .07 volts. ing increasing efficiency in both the work required for the original. of students and the equipment of the War -Editor.] = 1 Department's various balloon training fields. The balloon school at Arcadia has 106 k miles of wire in use for teaching military V io-> communication. For the purpose of dem- N. \ >v onstration it has a complete system of wir- \ Ny,^ ing strung as it would be in the front line \ trenches on the battlefield. N \ Communication ^r?. posts and stations for alt kinds of messages 'n''^. \^ are used by the students the same as sol- \ diers use them at the front. ^o- A good part of the country southeast and % southwest of Arcadia is laid out with lines N of communication to this balloon school, 1 \ \ similar to part of a sector at the front All of the balloons, when aloft, are so wired \ \ that they can be lined together with any \ \ trench, doubled up for any work together, \ \ or they can be cut off from the trenches \. and talk only with their own chart room and winch or operating crew on the ground below. h It is reported that the U. S. Government For Aii Ordinary Radio Calculations This Simplified Graph Fills the Bill as Well as the purchased the Sayville, L. I., Radio Station Larger One Publlsht In the September Issue. It Gives the Value of inductance and shortly after the declaration of war. Capacity for Wave Lengths from 600 to 20,000 Meters. January. 1919 ELECTRICAL EXPERIMENTER 633

Building a 3 -Inch Spark Static Machine

By DR. E. BADE

holes Each of the two rubbers consist of a board FRICTION is one of the commonest up. But before they are fastened two sources of static electrical excitation. of suitable size for a glass rod which is used on which soft, thick felt is glued. A spring Every one has noticed how the hair as an axle are provided for. presses the rubbers lightly against the glass crackles under the comb in dry A round glass plate one foot in diameter plate. In order to prevent the rubbers from weather. The same sound is heard on is procured. This is usually the most ex- falling out a short piece of wood is nailed stroking the back of a cat, and, if the room pensive part of the machine. It is best to to them so that it projects and catches is dark, sparks may be drawn from pussy's purchase it from a large electrical supply against the frame. Each rubber is now fur. But for developing large quantities of house, so that one does not get a plate covered with an amalgam consisting of two electricity by friction a static machine is unsuited for electrical purposes. A glass parts of mercury, one part of tin, and one

utilized. The simplest form of such a static rod one foot long and a half to ^ of an part of zinc. This must be evenly dis- machine which will develop sufficient elec- inch in diameter is taken for an axle. Two tributed over the surface with the finger. tricity for all kinds of devices, as it gives a small wooden rings serve to hold the If this will not adhere a little lard (fat) spark ranging from one to three inches in cemented plate to the rod. One should be may be used. length, according to the neatness and exact- careful to see that the axle is perfectly The conductor with the metal comb is ness of the finished apparatus, altho one of horizontal and the plate exactly perpendicu- made next. The former consists of a four excellent construction will give a larger lar. One end receives a handle and a or five inch hollow brass ball fastened to a spark, consists of a revoluble glass plate, a wooden ring which prevent it from slipping glass support. The ball receives two holes rubber and a conductor. The capacity of the from the supports. thru, which a brass rod is placed carrying conductor can be heightened with a well in- Now a "rubber" is made from three pieces the comb. The top of the ball also receives sulated iron ring capable of being attached of wood. The lower part is made from a a hole which will later carry the ring as or taken oiT from the conductor at will. piece 214 inches wide and 4 inches long. well as other pieces of apparatus for ex- The wooden frame is to be made first. It The sides, which are made to slant slightly periments. The metal points of the comb is constructed from hard dry wood (walnut upward, are 4J4 inches high. This frame is are attached to two rings of tin, each of inches which is fastened to a wooden ring. The or mahogany) ; the base is 20 inches long, supported by a glass rod 4 long The other metal rings are each 3 inches in diameter. 12 inches wide, and 2 inches thick ; the which is sunk into the wood. edges are beveled off. The two supporting end is placed in a fork 4 inches long, 2 The points consist of ordinary thumb tacks. arms can be made from thinner wood, but inches wide, and l/z inch thick. With the When the rings are placed between the each should be IS inches long, 4^4 inches aid of this fork the frame is fastened to glass plate, the points should be at least wide at the bottom, and 3 inches wide at the the base board by winged screws. But be- ]/i of an inch from the glass. Under no top. These arms, which are dovetailed to fore this is done a small brass knob or ball circumstances should they touch the plate. the base, are fastened with two screws is attached to the frame which in turn is A flap of silk is glued to the rubber which countersunk ; the holes being later plugged attached, by means of tinfoil, to the rubbers. (Continued on page 673) 634 ELECTRICAL EXPERIMENTER January. 1919

How I Built a Model Gyro-Electric Destroyer By LeROY H. MAHONY

illustration represents a 25-inch I next turned my attention to the m-ain the large quantity of silex in the substance THEmodel of Mr. Gernsback's "Gyro- axle and the gyroscope. The gyroscope require the tools to be extremely hard and Electric Destroyer." The entire ma- I turned from two pieces of }i inch wood even then they are subject to rapid wear. chine with the exception of the 8 inches in diameter. To the side of it I It also contains an oil which prevents nails Gyroscope and the driving motors secured a small sprocket for the driving driven into it from rusting. was built of "Meccanno" parts. chain. The gyroscope must run FREE of EINTHOVEN GALV. STRING. A commercial form of Einthoven galvanometer string is shown below. The case, E, contains the fine wire carrying the current to be measured. The figure shows schematically the detailed construction of the suspension for the fine wire E, which must be as fine as possible. Platinum, silver or aluminum can be used, but it was found that even a smaller diameter can be obtained by using quartz or glass fibers, these being platinized or silvered. The ends of the wire are soldered to T-shaped members, which are held by the set screws C and F at the ends. Adjusting the tension of the wire is a close operation and it is carried out by mounting the upper wire carrier upon a rod having tihe cam K at the upper end, the rod being normally pushed up by a spring L. The lever K', presses the rod down, this lever being operated by the this arrange- micrometed screw J. With ment a very fine adjustment of the wire is secured. Contributed by SAMUEL COHEN.

Here Is a Fine Model of the "Gyro-Electric Destroyer." It Is Fitted with Electric Motors and All. It Was Constructed by the Author from "Meccano" parts. It Stands 25 Inches High and Weighs 15 Pounds.

I first constructed each side of the big the main axle. The axle itself is 18 or 20 wheel. To a bush wheel I bolted eight IZ'A inches long and must be securely fastened inch strips equally divided into angles of to both sides of the wheel. The axle car- 45 degrees. I then bolted together seven ries two armored cars (the construction ot 12'/i inch strips overlapping two holes each. which I will explain further on), two I bent this around the ends of the side sprockets, equidistant from the center, and braces and fastened it to them by means also securely fastened to the main axle, of angle brackets. In the same way I the gyroscope, and the engine cage. A constructed the other side. I selected pairs lever action that moves the gyroscope from of S'A inch strips and bolted each pair left to right may be constructed also, at together, overlapping them one hole. Three the discretion of the builder, because his center treads, the same in circumference material for the gyroscope will again un- as the sides, were then made of seven doubtedly differ. The lever action must more IZyi inch strips, overlapping two be extended down into the engine cage. holes. It now remained to connect the The armored cars were lastly put to- two side and the center tread together by gether. For each car, eight large plates, means of the preconstructed pairs of SJ4 with the flanged edges flattened out, were inch strips. One pair was bolted at right bent so as to form half a cylinder. Each angles to each side brace and one equally pair was fastened together, overlapping one placed between them. To preserve more hole and making a complete cylinder. Then fastened, stability, I connected the side braces with two of the cylinders were one 3'/2 inch strips. This completed the main on top of the other, with strips bolted to wheel. each side and extending over the top so The next part to consider was the en- that the car might hang from the main gine cage. Three small plates fastened axle. Two inch axles (or better wooden side by side with Syi inch strips, composes models) were collared to the front and of each side, while each end comprises a rear of the car to give the appearance large plate with the flanged edges flattened projecting guns. The model was now com- elaborate his out. The sides and ends were fastened to- plete. The builder may on gether by angle brackets. It is necessary model by cross-bracing with string, and so to fasten inside the cage two motors {"prti- forth. The entire model weighs 15 pounds. erably electric), one to drive the gyroscope separately, and the other to propel the en- TEAK THE HARDEST OF ALL tire machine. As to the position in the TIMBERS. cage for these motors—that is left to the discretion of the builder as his type and People familiar with different kinds of size of motors may differ from those of the wood are aware that African teak is the writer. However, the motor driving the hardest timber known to the mechanical in- gyroscope must be placed in the center as dustries. So indestructible is this teak wood the gyroscope must be driven in the cen- that vessels built of it have lasted over one Those Who Are Interested In Building ter. The other motor must turn the axle hundred years. The peculiarity of this an Einthoven String Galvanometer for of the wheel by means of chain and wood is its hardness and great weight, caus- Measuring and Recording Radio Signal sprocket. On each side of the cage is ing extraordinary durability. Its weight Currents, as Described In the Septem- ber and October Issues, Will Find This fastened a 3^ inch strip so that the cage varies from 42 to 52 pounds per cubic foot. Detail of the String Suspension of is suspended from the center axle. It works easily considering its hardness, but Value. January. 1919 ELECTRICAL EXPERIMENTER 635 A Simple Study of Currents and Magnets By Prof. E. H. JOHNSON, Dept. Physics, Kenyon College

(Conclusion)

of electromagnetic Again, our now the wires J and K are joined to a into the required form, and having its two motor. IFdirect current circuit of several volts, limbs wound with several layers of insu- riyht-hand rule should be applied, consid- the wire, H, will rotate about the iron lated copper wire (about No. 20 or No. 24). ering the current as flowing up or down, rod, D, which is now a magnet, and it One end of the wire from the magnet dips as the case may be, in the spoke touching will be found that the direction of this into the mercury and the upper end is the mercury, to see if the rotation is what motion will depend on the direction of the joined to a binding post, E. When a direct should be expected. current in the wires. It may take a little current is past between the posts, F and E, Other experimental devices such as these will study to see how the action is in accordance the wire, C, will be moved sidewise so as readily suggest themselves to the ex- with the principles previously defined, but it to leave the mercury contact, and thus will be found to-be no exception to the rule. break the circuit at that point. Then, since the magnetic field about the wire, C, is gone, it will again swing back into the mercury, completing the circuit. Thus the process will go on much after the manner in which an electric bell continues ringing. Again, one of the rules should be applied to see why the wire, C, moves just as it does, and how its motion is effected by the direction of the current. Still another simple device illustrating the same principle is that known as Bar- low's wheel. See Fig. 6. The electromagnet used in the preceding experiment may also be used here. The wire C (Fig. 5) is Barlow'i irhe'' replaced by a carefully balanced, rimless wire wheel, W, which is mounted on two wire supports held by the post A. The Barlow's Wheel—the Simplest Electric Motor wheel may be made of light copper wire for Experimental Studies in Magnetism. The (say No. 20) with spokes about 3 inches Spoked Metal Wheel Makes and Breaks Con- An Interesting Method of Producing Motion tact for the Field Magnet, by Passing Thru long, and the only difficulty will be to get by the Interaction of a Magnetic Field and a Mercury Well. it accurately balanced. It should have 10 a Current-Carrying Conductor "C." The or 12 spokes, which may be soldered to a Suspended Wire "C" Dips Into a Mercury Well "G," Completing the Field Coll Circuit. Another method of producing motion by heavier copper wire for a shaft to be laid The Wire Swings Back and Forth Rapidly. the interaction of a magnetic field and a across the slightly hooked ends of the sup- current-bearing conductor is illustrated in porting wires from the post, A. When the perimenter, and he should learn to look at Fig. 5. A heavy wire, A, is bent into the balancing is fair the wheel should turn as all such arrangements with that keen appre- form shown with a hook at the upper end, easily in one direction as the other, or re- ciation which sees not only the wires and B, from which is suspended loosely a main at rest in any position. The mercury mechanism, but which recognizes at once straight wire. C. The lower end of this pool, with which the ends of the spokes the underlying principle of its operation. wire just touches in a pool of mercury, G. make contact, is connected as before, by a When this habit has been formed and some which is contained in a small hollow in the wire to one end of the coils of the magnet, of the information which it will inevitably supporting base board. A horseshoe elec- and their other end is joined to the other bring, has been acquired, the entire field of tromagnet, M, lies with one pole on each binding post, B, so that a current may pass electromagnetism, including dynamo-electric side of the drop of mercury. This magnet thru the apparatus between A and B. In machinery in all of its phases, will open up may be made from a rod of soft iron 6 this case the action will be continuous with with a surprising simplicity and conse- inches long and J4 inch in diameter, bent the proper current, and we have a fair type quently with endless interest.

ELECTRIC FLASH-LIGHT IGNITER. A "BATTERY-LESS" MAGNETO Powder box Potvaer box. DOORBELL. Toc/i Having some difficulty when taking flashlight pictures with cartridges, with the fuse A small magneto generator is placed in a not igniting the powder or putting the sub- box (properly stained and finished) on the ject on guard, frequently catching him with back of the door. A turn of the knob rings his eyes closed, and being badly burnt by the bell, which may be an ordinary vibrating the powder once, I constructed the appara- bell. Best results are obtained by rewind- tus shown in the accompanying sketch. It ing it to from 100 to 300 ohms. An old will run nicely on four dry cells. The f/ino principle is that when the batteries are short-circuited, the wire gets red hot. ^^^Jl The wires leading from the powder box are the kind knowm as bell or annunciator 1 P^'''' fM.l^ey wire. Inside the box, the wire wound be- 1 1 To coil m |-| tween the tacks is about No. 40 gage. When the box is constructed, place some powder in the box, press the push button, and off goes the powder. To make the apparatus 1 Iscufcfiem portable, put the batteries in a box, and mount the powder box on top of this. In fr *"K(S)\f this way the operator may appear in the picture himself, if the wires are concealed behind furniture and his person. This also WirCPten P Tocal catches the subject off his guard, giving Turn the Key Handle and, Prestol him a natural pose ; it enables the operator — the Generator Rings the Bell, F,g safe Doing Away with 5 to be at a distance from the powder. Batteries. If a spark coil is procurable, it can be used PorrderOot instead of batteries by running a pin thru crank escutcheon plate from a magneto each side of the box making a spark gap, telephone may be placed on the front of the ^'Push button connecting up to the coil, and pressing the door. This device when properly made is button. I have used this apparatus ex- neat in appearance and does away with all tensively and successfully myself. Several Useful Schemes in Igniting Flash- battery troubles. light Powder Electrically. Contributed by FRED C. DAVIS. Contributed by CHURCHILL GERRY. :

636 ELECTRICAL EXPERIMENTER January, 1919 Experiments in Radio-Activity By IVAN CRAWFORD

PART 1—Ionization

RADIO-ACTIVITY is one of the substance furnishes an efficient means of rocal of this time is then the measure of greatest mysteries of today. The measuring the intensity of the activity. the discharging current. The electroscope modern scientists, however, thru ex- The construction of a super-sensitive is then recharged to the same point and

• tensive experiments have succeeded electroscope suitable for making these placed over the substance to be measured. in throwing considerable light upon the measurements is clearly depicted in Fig. 1. The time required for the leaf to pass over subject. The term radio-active is generally The metal shell consists of a large oil can the same five spaces is again noted. The with the bottom difference between the reciprocals of these and spout removed. two time elements is then the measure of Two round holes the discharging current due to the presence Sulfur are cut opposite of ions produced by the radiations from the each other about substance. Exprest mathematically the half way up the discharging: current 1, which is proportional Oil con side. As is clearly to the radio-activity is proportional to la shown in the draw- (l/t'-l/t) where t' is the time of discharge ing the gold leaf is in the presence of the substance, and t is fastened to a brass the time when empty. Thus by comparing strip which in turn times the radio-activity of equal massvs of is suspended from various substances can be measured. a sulphur bead. In- Uranium oxid is taken as a unity and to the other side of uranium nitrate, thorium nitrate and uranyl this bead is fast- chloride were compared with this. The re- ened a wire which sults are shown in the following table .Microscope passes thru the sul- magnifier Rela- at the phur block tive top of the cham- activ- Open here ber. Another wire Substance. Formula. Time. ity. Empty 412 sec. Adhesive is then past thru -l- B Uranium oxide. UOi 26 1.00 v. the block and bent Uranium nitrate UOa(NOj),.6HjO 86 .26 as shown. The sul- Uranyl chloride UCl. 41 .61 Sulfur oeaa Suirur Thorium nitrate TH(NO,),.12H20 63 .38 is < 1 phur block made by pouring melted It will readily be seen that the activity of sulphur into the a substance is proportional to the amount opening and allow- of uranium or thorium it contains. There ' ing it to harden. are other considerations, however, which

'/ I In order to charge , f~ affect the experimental results, such as the the the electroscope state of the substance, whether powdered or bent wire. A, is in lumps. Every electroscope also is dif- turned so that the I ferent, and all quantitative experiments J / 1 portion f. lower should be conducted using the same instru- makes a contact ment. with the brass It will be found that the distance between charged strip. A the substance and the gold leaf affects the rod is then applied I rate of discharge. For uranium compounds t ' 1 \__L to the other end, the most effective distance is about 3 cm., Full curve represents theoretical resu/t Brass,' '\Scale attached B, until the desired while for thorium compounds it is about Dotted curire represents experimentalfor strip to t)ross strip charge is attained, - 5 cm. Ionization by radio-active rays is uranium alpha particle . . - 5 -2- t. the wire may when by no means uniform along the path of the be turned back The Most Important Property Possest by the Radiations of Radlo-Actlve rays. In Fig. 3 is shown the ionization Substances Is the Power of Discharging Electrified Bodies. Hence, the rod. The with the caused by a sheaf of parallel rays Discharge of an Electroscope Placed In the Vicinity of the Radlo-Actlve as de- gold leaf is "'at- Substance, Furnishes an Efficient Means of Measuring the Intensity of f"'^ j'x''\t."u termined by Geiger. The range is laid out tached to the brass the Activity. horizontally in cm., the number of ions are strip by means of laid out vertically. It will be seen from this In order to employed in referring to such elements as a small drop of some adhesive. graph that when the alpha particle begins their com- observe the discharge, a small low power uranium, thorium, radium and to lose some of its enormous speed it be- pounds which possess the property of emit- microscope having a scale on the eyepiece comes a more effective ionizer ; near the end is mounted in one of the ing radiations capable of penetrating many is used. This of its path, however, its power suddenly de- the substances opaque to ordinary light These apertures by fastening a brass tube to creases. the rnicro- radiations also have the power of affecting shell of sufficient size to allow The experimenter will find innumerable adjusted. similar photographic plates, ionizing the gas scope to be easily A other applications for this electroscope tp window is thru which they pass and causing fluores- brass tube with a ground glass (Continued on page 673) cence on certain substances placed in mounted in the opposite aperture. This is their vicinity. It is deemed unnecessary to to facilitate the illumination of the cham- enter further into the explanation of radio- ber. Using this instrument the rate of dis- activity as it has been well described by charge may be accurately measured by not- Mr. Jerome Marcus in previous issues of ing the fall of the gold leaf on the scale. this magazine. It is the purpose of this The substance to be measured is placed on series of articles to merely outline some a grounded plate and the electroscope experiments on this extremely interesting placed over it. The radiations by means of subject. their ionizing properties cause the charge The most important property possest of the gold leaf to be dissipated. In Fig. 2 by the radiations of radio-active substances is shown a photograph of such an instru- is the power of discharging electrified ment which was constructed by the author. bodies. The theory has been formulated Some very accurate measurements have that this discharge is due to the production been made using this instrument. of positively and negatively charged car- To determine the activity of an unknown riers by the rays. These carriers, or ions substance the electroscope should first be as they have been termed, move with uni- charged until the gold leaf coincides with form velocity and the rate of production is one of the markings on the scale. The time leaf to pass over five di- proportional to the intensity of the radia- required for the Finished Super-Sensitive Electroscope for tion. The discharge of an electroscope visions on the scale should then be noted the Measurement of Radlo-Actlvlty. It Is placed in the vicinity of the radio-active with the electroscope empty. The recip- Made from an Oil Can. 637 January. 1919 ELECTRICAL EXPERIMENTER

TESTING THE VACUUM GAGE. REMOTE CONTROL SWITCH FOR bell magnets become energized, which lifts the hammer or trip arm and disengages the The experimenter often wishes to test LIGHTING CIRCUITS. material weight allowing switch to drop and close a vacuum gage. The best way to test such After obtaining the necessary the handle from the lighting circuit a gage is to compare it with a glass U- listed below, remove made To reset and cut out lights ; open door of tube mercury gage as indicated in the knife switch and substitute a weight from 2" length of conduit pipe and Vi«" x iron box and lift weight until engaged by 2^" stove bolt. The head of stove fiemforced (lex lamp cord is filed flat on one side so as to bolt altach. connec/or ir/ll> Hubbel or olher be properly engaged by the trip arm. plug. The bolt is placed in one side of pipe, and pipe filled with melted lead and allowed to cool off. The threaded end of bolt is then inserted thru hole (in insulating bar across knife switch) formerly occupied by screw holding handle. If properly placed this weight does not come in contact with either of the switch blades. Now place the fuse block in upper left-hand corner of the iron box as shown on sketch, then place knife switch in bottom, the one side of base being against back of iron box and the whole switch so mounted as to allow weight to swing down and close switch without hitting side of box. The rubber bumper is then placed on bottom of box either with small stove- bolt counter-sunk in the rubber or with a small wood screw from the under side. The object of the bumper is to prevent the weight from snapping off the insulating cross piece of switch when switch drops. The casting on bell for holding gong should be removed with a hack- Mounted in T'l' Iron cut-out or pi/// 6ojt Testing the Vacuum Gage With a Glass U- saw just beyond the screw hole, and Gage. The Latter Is a Common Construction of "Remote Control" Switch Which Can tube Mercury cut off with Instrument Used By All Engineers and Can the ball hammer can be Be Made With a Buzzer or Bell Movement to Trip the Be Made Very Easily. The Atmospheric Pres- a pair of cutting phers, leaving the Weighted Knife Switch Blade. sure Acts on the Mercury In the Open Tube hammer arm intact. "A." door. In placing the bell it will probably be hammer arm of bell, then close the contact clips of knife sketch. The bent tube ABC, having about necessary to build it out from the back of Keep pivoted and with vaseline. This 3/8-inch bore, is connected by suitable fit- box so that the trip arm centers over weight switch lubricated control tings to the pipe or nipple D, and the lat- on switch. This building out should be switch can be used for distant cut-in burglar or fire alarm ter is connected with an air pump or con- done with either a piece of fibre, porcelain or in conjunction with lights when alarm denser. The gage to be tested is placed or iron washers. No wood or combustible systems, cutting in the on a tee-connection. The U-tube should material should be used. Bend trip arm a» operates, and doing away with the necessity lighting wires. be about 36" over all and about half filled shown in sketch, so as to engage the filed of running heavy requires it, a ground wire with mercury. When there is a partial side of stove-bolt-head which protrudes Where the law with short vacuum made at D, the atmospheric pres- thru the weight. can be attached to the iron box a sure acting on the surface of the mercury All mountings should be made with stove- stove-bolt and the. box grounded to the in the open tube AB, being greater than bolts, drilling holes in iron box where neces- electric conduit system. is to make this the pressure acting on the surface of the sary. If box is thick enough to allow thread- The following material required the mercury at screws be used. apparatus: mercupf in the tube CB, ing machine may One 7" X 8" iron cut-out or switch hox. the original level EF will fall in AB, as to The rubber bushing to protect bell wires One two-wire main line plug fuse cut-out block. G, and rise in CB, as to H, and the dif- can be inserted in the box at any convenient Two dry batteries One two-pole single-throw knife switch. ference of level between and G as in- of linen tape or H place and a narrow piece One iron box bell. dicated by the dimension "//* measured in wire twisted tightly around the inside will One push button. connector. inches, will be the inches of vacuum which serve to hold it intact. One H" B. X. box lamp socket bushing. gage should indicate. While One rubber the vacuum Place the attachment plug on one end of One attachment plug. most manufacturers of vacuum gages are the lamp cord, knock out one of the punch- One 3/16" x 2%" stove bolt. knob from old door bumper. equipt with a U-tube mercury gage, they ings in the iron box and place the B. X. One rubber One 2-inch length of 1" conduit pipe. generally make comparisons with another this and connector, insert the cord thru Two ft. No. 14 B. S. gage double-braided wire. gage, known to be correct with the U-tube wind the cord with tape on the inner side Two ft. reinforced flexible lamp cord. gage. For testing a vacuum gage at a of the connector so that the clamping Proper quantity of bell wire. plant not equipt with a mercury gage, the device can be tightened thereby holding Contributed by E. C. O'DONNELL. to usual practise is to compare the gage lamp cord, preventing pull on the connec- LampS: be tested with one considered to be cor- tions at fuse block and at the same time Jlloclt. plug rect Connect serving as a bushing for the cord. insirted in . 0^0 Contributed by other end of cord to fuse block as shown. fme socHI PETER J. M. CLUTE. Make all connections as shown using the 0000 No. 14 wire for the lighting circuit and Houit fuse bloclr ,i//t7cA plug circuit. nserted in ordinary bell wire for battery (^ fuse soc/ref 0. Only one blade of the knife switch car- House fuse lamps ries for the ordinary two-wire 'pQQ- dlocle current Solid lighting circuit For the three-wire circuit Bell liov. supply the two blades are used and an additional lamp cord and attachment plug are re- Bell quired. Button m^ Installation: This apparatus should be Fuit mounted on wall close to house fuse box and not more than 6 or 6^ ft from floor. To connect to an installation one fuse is J ^* removed from the house fuse box and the attachment plug inserted in its place, the Sallerij fuse can then be placed in the "fuse" socket Ballery of the apparatus. The bell circuit can easily Hook-up of Remote Control Attachment to a be run and the button and batteries instal- How the Remote Control Switch Is Connected Two-wire Lighting Circuit. The Control Cir- point. led at any convenient Up to a Double-pole Knife Switch For Con- cuit Wires May Be Ordinary Bell Wire as System. : closing battery circuit the trolling Lamps on a Three-wire This Is a Battery Circuit Only. Operation By 638 ELECTRICAL EXPERIMENTER January, 1919 Experimental Mechanics By SAMUEL D. COHEN LESSON IX

Boring and Drilling. the size of the hole should be marked with be cleaned up perfectly true around its the lathe can be used with suc- a pair of compasses, first chalking the sur- circumference. Thereafter several lighter THAT impressions should cess for drilhng purposes is inen- face, and four center be cuts may be made, until the diameter is tioned in one of the earher lessons made at opposite points on the line. These brought to the proper size. The inside of this course. The subject will be are necessary to act as guides should the caliper should be used in this work to ascer- further considered in the present line get effaced. A start is then made, but tain the diameter. Precaution should be lesson, and several useful kinks regarding before the point of the drill has fully en- taken to set the slide-rest perfectly true tered the metal an examination should be made to see that it is ^eoa center cutting truly within the circle marked out. If so, the work may be proceeded with. Should the drill by chance happen to cut slightly to one side, the fault can be rem- edied by cutting a narrow groove at one side of the hole. This may be done with a narrow-pointed diamond chisel. The Holding a Twist Drill In the Lathe by Means groove should be of a Monkey Wrench. The Back of the Drill Boring Out a Casting In the Lathe by Means of a Boring Bar "BR.' Is Placed on the Tall-stock Center. The Casting Is Secured by Bolts "B" to the Saddle "OS." made at the side toward which the hole so as to insure a parallel hole being bored. requires to be cor- If the diameter is found to alter, (should it drilling in the lathe will be given. When- rected. Here the drill may again be applied, taper, for example), the slide rest can be ever it is desired to make a hole of general the effect of the newly made groove being changed accordingly. By the use of a self- size in some material, it is usually done by to draw the drill toward the center the of acting feed on the slide rest, the hole should the use of a drill of the desired diameter, circle. The drill should then be turned sev- be perfectly parallel, provided the head said hole being made in one operation. eral times and the hole again examined. If stock and lathe bed are set true, the posi- There is still another method of making a necessary, the drawing process can again be tion of the slide rest not at all affecting hole, and that is by boring. It can be done repeated until the hole is exactly central. the work in this case. by a single pointed tool cutting into the The reader, of courst, fully understands If it is desired to bore certain work which material in successive cuts, which gradually that this drawing process should be done is too large to be chucked on the face- enlarges the opening until the desired before the full diameter of the drill com- plate or chuck of the live spindle, it is prac- diameter is obtained. mences to cut, as the grooving plan can have tical to secure the work to the saddle of Practically all small holes are always no further effect in drawing over the hole, the lathe, as shown in Fig. 3. This is done drilled, while large ones are bored. In order after the full diameter of the drill enters by supporting the boring rod between the to drill a large hole it requires considerable the hole. live and dead centers, the boring rod carry- driving power, also the removal of a con- At certain times it happens that the rela- ing the cutting tool. Engine and pump siderable amount of metal. However, if tive positions of the parts are reversed. cylinders, field magnets for dynamos and the method of boring is utilized, a rough Thus the work to be drilled is held in the motors, also bearings of engine bed plates hole may be cored thru the casting when chuck, the drill being fed up to the work. are examples of work which can be done the latter is made in the foundry, and this Many times it proves convenient to first in this manner. It is essential to have a can be enlarged later by the use of the drill a small hole, then a larger size, and lathe with a saddle, actuated by a self-acting boring tool. If the work is not made of lastly use the full size drill. feed motion, unless a complicated boring cast material, it will be necessary to drill a If the work is held in live the chuck, the bar fitted with its own screw feed motion hole large enough to permit the boring tool drill should be fed by means of the tail- is used. Fig. 3 shows a cylinder W of an to make its first cut. stock center, and held firmly thereto. The engine, which is secured to the lathe saddle, drill call be held either in In drilling small holes, say up to one a drill chuck C. S. This is done by clamping the cylinder inch in diameter, it will be found that twist fitted with a mandrel for the dead center with two bars, each having two holes, the drills give most favorable results, as they spindle, as shown in Fig. 10, Lesson 6, or distance between which should be greater are dependable for producing an accurate by setting the center hole of the drill onto than the diameter of the work to be secured. the its and straight hole. It is usual, in practise, dead center, shank being held with The bars, R, R, are laid across the top of to fasten the drill in a self-centering chuck, a wrench in order to prevent it from turn- the work and clamped down by means of ing, see Fig. 1. is as explained previously, and to feed the When the hole made two bolts, B. These heads fit into the work up against the drill by means of the in this manner it is necessary to start the slides of the lathe saddle. The cutting tool, drill centrally. mandrel of the tail stock in the lathe. The An accurate starting point C. T., is held on the boring rod, B. R. It first step before attempting to drill is to is obtained by the use of the cutting tool is revolved by the live center while the placed in slide accurately mark the spot where the hole is the rest. This method will cylinder is slowly carried along the lathe desired, making a heavy center-prod or insure a proper drilling point. bed toward the live headstock by the self- mark, so as to guide the point of the drill Boring is chiefly used when it is desired acting feed motion applied to the saddle. at the start. To drill large holes, a circle to make a large hole. However, at times it Before attempting to bore into the work, is simpler and easier to bore a small hole it is advisable to see that the work is firmly of proper diameter and accuracy than it is (Continued on page 670) to drill it. But care must be exercised to see that there is a proper clearance at the lower part of the cutting tool, as indicated A B in A, Fig. 2. If the tool is improperly set so that the lower part scrapes against the side of the work, as shown in B, Fig. 2, its proper functioning will then be interfered with. The tool will not only be prevented ) ( from cutting into the metal, but due to the rubbing action against the metal, it will be c heated and caused to lose its temper, thus destroying the cutting qualities of the tool, Fig. 2 how the Boring Tool Is Made: a If Self-Hard- besides making an inaccurate hole. ening Tool Steel Point Is FJtted Slldably In a Hole In the Boring Bar. The Point May Be It is advisaiile to make the first cut a Proper Clearance on Boring Tool (Left) and of Square or Round Stock. fairly heavy one, in order that the hole may Improperly Ground Tool at Right. :

January, 1919 ELECTRICAL EXPERIMENTER 639 Experimental Chemistry By ALBERT W. WILSDON

Thirty-second Lesson

PHOSPHOROUS: History. First.—It is treated with Sulfuric Acid, Physical Properties. which changes it to a soluble phosfate PHOSPHOROUS was discovered by H.Ca[P0.]2. 1. It is found in several altotropic forms, Brandt, an alchemist, in 1669 at Ham- the most important being the yellow and Ca3[PO.]2 + 2H2SO. = H.CaEPO.la + 2CaSO. burg. He gave it the name Phosphor the red varieties. [light bearer]. Gahn, in 1769, found It might be expected that the Sulfuric 2. Yellow phosphorous is a colorless, it to be a constituent of boneash, and Acid would change the phosfate salt into transparent to translucent, wax-like solid. about 1775 Scheele first publisht his method phosforic acid, but the Sulfuric acid used At ordinary temperatures it is sufficiently is not very strong and the reaction goes soft to be cut with a knife, but at lower but halfway, producing an acid salt. It, temperatures it becomes more brittle. however, changes the insoluble phosfate I. I I I I T~^. . . to a soluble one and precipitates the Cal- Id cium Sulfate, which is then separated by

'I'i'i' i filtration or settling. Second.—The liquid is next evaporated, and the solid residue from the evaporation is strongly heated, a process which breaks it up into Calcium Metaphosfate [Ca[P0>]2]. H.CatPO.la = CaLPOala + 2HjO Third.—The reducing agent, carbon, is next added and thoroly mixed, and heat is again applied. When two-thirds of the Phosphoroub distills over, the remainder again forms Calcium Phosfate. 3Ca[P0,], + IOC = Caj[POj], 4- lOCO + 4P To obtain the whole of the Phosphorous, Silica [Si02] in ;he form of sand is introduced, and the following reaction takes place

2Ca[P0,],-l- 2Si02 -|- IOC = 2CaSi03 -|- lOCO + 4P

Great care is taken not to have the hot Phosphorous in contact with air, and retorts are arranged so that the Phosphorous runs into cold water. See Fig. 153. The Phosphorous must be either redistilled or prest thru chamois skin to get rid of carbon />> /55 particles, etc. It is then run into small moulds of copper or glass. Preparation of Phosphorous In the Electric Furnace. A Mixture of Carbon, Phosfate and In the Preparation of Phosphorous Great Care The manufacturing process is detrimental Flux Is Heated by the Passage of the Elec- It Taken Not to Have the Hot Phosphorous to the health of the workmen. Some of the tric Current. Electrodes at G-G. The Phos- In Contact with the Air, and the Retorts Are phorous Vapors Pass Off Above to a Con- Arranged so That the Phosphorous Runs Into fumes have to be inhaled, and the breath denser, Being Condensed Under Water, While Cold Water. at night is often luminous. The element the Slag Is Tapt Off Below at C. attacks the teeth and jawbones, especially lower which is sometimes entirely of preparation from this source. Liebig in the jaw, 3. It burns the flesh when handled out eaten thru failure to cleanse the teeth. 1840 used phosfates as a fertilizer for away of water, and these burns are slow to heal, plants, while Romer [about 1833] first ap- The electrical process has practically re- on account of the poison absorbed. For plied ij to matches, thus revolutionizing the placed the old method. In an upright pear- this reason this element should always be means of obtaining fire and light. shaped furnace, an intimate mixture of Car- manipulated with a pair of forceps. bon, phosfate, and flux is heated by means 4. It is insoluble in water. It is soluble 15° Occurrence. of carbon electrodes in the electric furnace, in 350 parts of absolute alcohol at C, as shown in Fig. 154. The mixture is fed and in 240 parts of boiling absolute alcohol. It never is found in the free state, but in thru the hopper H, the carbon electrodes It is soluble in 85 parts of absolute ether, chiefly as calcium phosfate [Cas[P04]2], the entering at GG. The phosphorous vapors in 25 parts chloroform, and in about SO principal constituent of bones. This occurs pass off above to a condenser, being con- parts of any fatty oil. Carbon-disulfid is in certain minerals as Apatit [3Ca3[PO.]2] densed under water, while the slag is tapt probably its best solvent, dissolving from and Phosforite [Ca,[P0,]2]. The latter off below at C. 18 to 20 times its weight without losing its being fluidity. All solutions of phosphorous in also known as Phosfate Rock, being 2Ca[POa]2 + aSiOj + IOC = 2CaSi03 + lOCO -|- 4P extensively used for fertilizing purposes. carbon disulfid should be preserved with Phosphorous is always found in plant and the greatest care. When spilled or other- /"/asA- J animal tissues, in the soil, and in sea water. wise exposed, the solvent rapidly evapo- ! rates, leaving the phosphorous in such a Preparation and Manufacture. finely divided condition that it inflames ^^^j^ ¥ spontaneously. It is obtained mainly from bones of verte- 5. It possesses a garlic odor, and is very brate animals, which usually contain from 55 ^^% poisonous. This odor somewhat resembles to of calcium phosfate, the hard parts M Ozone. 60% ^^ F/OiA 2 s SSe§1-J- ' of invertebrates being mostly Calcium Car- 6. The phosphorescence, visible in the OutS '11'^';' ^\ dark, when exposed to the air appears to bonat, CaCOz. These bones are first burned ^^ or else distilled. In either case the ash is be due to the slow formation and spon- combustion of phosphin. the same, but in the latter the carbon is ^ taneous IVafer^i boneblack, which in the " 7. Phosphorous is a very inflammable retained as former in 1 gives rise to carbon dioxid. The volatile element, igniting spontaneously in air at * substances driven off are ammonia and ci .TIk ,^k T" 50° C. For this reason it is kept and cut ' under water. Phosphorous, when kept under other nitrogeneous products, such as water, f/g /55 a carbon dioxid. etc. The ash, mostly Cal- water and exposed to the light, undergoes cium Phosfate with a little calcium car- slow oxidation, becoming covered first with An Interesting Experiment In Which the film, which slowly turns red. honat, is reduced and phosphorous obtained Phosphorous from Match-heads Is Extracted a white, opaque by three steps. by Means of Distillation. (Continued on page 666) ^

640 ELECTRICAL EXPERIMENTER January. 1919

laai tsttoefaonstnmttatitfaao JiDLul'a

This department wlU award the foUowing monthly prizes: First Prize. J3.00: Second Prize, $2.00; Third Prize, $1.00. The purpose of this department is to stimulate experimenters towards accomplishing new things with old apparatus or old material and for the most useful, practical and original idea submitted to the Editors of this department, a monthly series of prizes will be awarded For the best idea submitted a prize of $3.00 is awarded; for the second best idea a $2.00 prize, and for the third best prize of $1.00. The article need not be very elaborate, and rough sketches are sufflcient. We will make the mechanical drawings. Use only one side of aheet. Make sketches on separate sheets.

FIRST PRIZE, $3.00 SECOND PRIZE. S2.00 THIRD PRIZE, $1.00

SIMPLE ELECTRICAL ALARM A "COLLAR BUTTON" COMPASS. FIXT CONDENSER IN A SHAVING CLOCK. This compass is very easy to construct, STICK TUBE. Herewith are submitted the details for and can be made with a needle, coljar but- An efficient and neat fixt condenser can an electrical alarm clock which I believe is ton, snap fastener, and a piece of thin steel, be made from a nickel-plated shaving stick the simplest one I have seen publisht in cut in the shape of a compass needle. After having cut the needle to the desired shape and size, punch a hole in the center. Over this solder the bottom part of a snap fastener. This completes the needle. Next, force a steel needle up thru the collar button so that it protrudes out of the top about one-sixteenth of an inch. Solder it firmly Hex nut from the under side. The needle is magnetized by rubbing it over a magnet. When it Piece of ^ is thoroly magnetized, place it on the needle jmt rubbertubing T|ii ^Jt/asfier point and adjust it so that it will balance and revolve freely. It can be mounted either in or out of a case as desired. I find that an old dollar watch hack makes a good

Snap fastener Solder lead}

A Ceryerat vi'enr of case.- B • Inlorged view of bmdi'ng post An Easily Made Circuit Closer tor Attach- Bell Will ment to Any Alarm Clock. The Collar oullpn Handy FIxt Condenser Mounted In a Shaving Ring Until Shut Off. Stick Tube. It Can Be Embedded In Paraffin Wax. your valuable magazine. A brass spring can as a container. First cut some tin- (s) is supported on an insulating block (c). foil to about 2 foot lengths and 1-3/4 inches piece of blotting paper is glued on to A wide, separated by 2-1/4 inch width par- the end of the strip to insulate it from the A Reliable "Collar-button" Compass. affined paper. This can be made as large alarm-winder. The operation of the alarm This li.Hse as it does not affect the needle. as desired, and by heavy pressure a large can be easily understood. When the dock performing ex- compass is very handy for condenser can be placed in the tube. Sol- alarm rings, winder key revolves which periments. der all lugs and make connections with releases the spring. When the spring is Contributed by J. H. ENGLAND. flexible conductor to binding posts. Bore released it strikes against the side of the holes in the cover and make washers as in clock, thus closing the circuit. KNOBS FOR ROTARY SWITCHES. (B). Fill the case with molten parafltn wax. Contributed by CHAS. WALLER. for rotary switches may be easily Knobs Contributed by E. S. HAGEMANN. FOR made from the vent stoppers on old storage UNIQUE "HOOK-UP" This is done by cutting the part TELEGRAPH SETS. batteries. A SERIES BUZZER TELEGRAPH off which has threads on it and drilling a SET. Herewith is a hook-up used by myself and thru, hole large enough to put a brass bolt Here is an efficient series buzzer tele- friend on our telegraph sets, the main ob- as shown in sketch. (Vsnt stoppers may be graph system. When the set is not in use ject being to eliminate closed circuit cells below. purchased from garagefe^. See cut put switches on No. 2, then when you wish and to use dry cells. When one fellow Contributed by MARSoN HENSEL. to call up your friend put your switch on wishes to call the other he opens his key g o) No. 1, disconnect the key switch and start his switch over to "send." When and throws icreiir Bruss . [3)£>/ sending. As soon as your friend hears receiving, he throws switch over to "re- your signal, he puts his switch on No. 1, ceive" and closes his key. The apparatus thus increasing the battery strength. Re- used comprises two sets, i. e., sounders and the batteries; «. e., if it sets dry member to reverse keys ; two D. P. D. T. switches, 2 f//e oft /;ere is positive at your switch on one end, make cells (3 each). Our system works fine and Boltery vent it negative at the other station. the extra-switch throwing is worth the . stopper Contributed by PRESCOTT OVERTON. battery saving. H.(tn4TTn Contributed by G. E. MEARS. wllii 3fattofJ'4' Stotiorj B' < cut off t)erB

ILeft:—Old Storage CeltVent Stoppers Make Good Switch Knobs. Right:— Discarded Dry I Cell Terminals Used as Switch Points.

The negative binding posts on dry cells make good contact points for rotary switches when filed down as shown above. Remove them with the pliers while the isonm — " — ^i' nuts are still on. Take one of these nuts phones /-S- :S; sketch. and file to opposite sides flat; see Sal ^' the screw post in it, placing v Then screw both in a vise. Then the head can easily be filed down without injuring the threads. Unique Series Buzzer Telegraph Circuit. Simple and Effective Switching Hook-up for KINGSLEY. Both Buzzers Work When a Station "Sends." TvtfO-Way Telegraph System. Contributed by P. B. January. 1919 ELECTRICAL EXPERIMENTER 641

AN ELECTRIC FIRE DETECTOR. noticed a scheme for twisting telephone other to the left. The reason for this can Herewith is a plan of a fire detector wires, contributed by Mr. Leach. While be seen when they are mounted. If they which I made myself. It consists of two this is a good method, I would like to sug- are the same, just take off the knife and batteries, a cigar box, an electric bell, a gest one that will not ruffle or twist the in- terminals and remount them in reverse or- sulation of the individual wires as other metlnids do. .Wood strip Porcelain knobs may be used as swivels. Attach two knobs to shop wall, do not tighten up screws, knobs should turn freely. Attach No. 14 wire loops to receive ends of insulated wires. Have wires same length; turn brace five or six times, pulling on it to take up slack and keep knobs from turning. Now slack off slightly on brace and knobs will spin, thus relieving the twist in each individual wire. Almost any length of wire Battery Knife siv/tct7 can be handled in this manner, equalling the factory product. Contributed by J. ESHLIMAN. A REVERSING SWITCH FOR SMALL MOTORS AND TOYS. A small but thoroly effective reversing switch for small battery motors and other ^m apparatus can be made from scraps found about most any workshop. In Case of Fire the Heat Expands the Copper An Effective Double-Pole Single-Throw Knifa First procure a fiber base about Wire Spiral, Causing It to Touch the Lower lyi" Switch Constructed from Two S. P. S. T. Contact Block, Thus Ringing the Bell. square and }i" thick. Next cut four (trips, Knife Switches. each Yi" long and %" wide out of a piece piece of bare copper wire made into a der. Then get thin strip of or fiber of brass about 1/16" thick. Then bore a a wood spiral spring, two blocks of wood, four to fit across the ends of the knives. This hole in one end of each strip and fatten screws, and two binding posts. Normally can be fastened on with small stove-bolts. it to the base by means of small wood- the wire made into a spring does not touch In the center of the strip bolt a small por- screws as shown in Fig. 1. the lower contact block, but when fire celain knob. breaks out it expands the wire spiral and Contributed by HENRY RHEIMS. completes th« contact, causing the bell to DRAFTING HINTS. "ointributed by WOHLPART. JOSEPH Tracings may be very readily cleaned SPARK PLUG TESTER MADE and pencil marks removed by the use of PLUG. benzine, applied with a cotton swab. It may FROM SPARE be rubbed freely over the surface without Most autoists carry a spare spark plug fear of injury to the lines drawn in ink, or in their tool chests which can be made to even water colors, but pencil marks and serve as a spark plug tester without de- dirt will quickly disappear. The benzine evap- stroying its usefulness. orates almost immediately, leaving the trac- The only thing necessary is to cut a ing unharmed. The surface, however, will piece of fiber or heavy cardboard to the be somewhat softened, and should be rubbed shape shown in the illustration. The hole down with a little powdered talc or chalk in the end is made large enough to pass before drawing more ink lines. the threaded end of the plug and serves Always sprinkle chalk or talc on surface as a holder. (dull side) of cloth, rub in with fingers, To test the plug in the engine, hold and wipe off before starting to draw ink the spare plug, sparking points up, by lines. means of the fiber strip. Touch the post on the plug to the engine cylinder and bring SIMPLE HOME-MADE SNAP the thread end of the plug in the strip SWITCH. against the binding posts of the plug in This is a very durable but simply con- the engine. structed snap switch. (A) is the screw A small spark or none at all will in- from an old dry cell carbon, the head (E) dicate a broken porcelain or carboned and being filed flat and inserted in a small block short circuited plug. A heavy spark will of wood (I) drilled as shown. The block show that the points of the plug in the A Handy Reversing Switch for Battery Mo- (I) is fastened to wood base ((J) with engine are too far apart. In cases of tors, Toy Railway Cars, Locomotives, Etc. screw (B). A strip of spring bronze (D) Throw It to Either Side to Reverse the Motor. emergency any means may be employed inserted thru the slot in spindle (F) as- that will hold the test plug without giv- Then take another piece of fiber about sures an excellent contact. (C) is a pin ing the driver a shock. for handle and (H) the supporting screw yi" square and 'A' thick and fasten two holes. Contributed by THOS. W. BENSON. metal strips to it as shown in Fig. 2. A handle may then be made and soldered to The spindle is held in the base by a small rivet at the bottom. This can be one of the strips. (In constructing this reverser, be sure and do not short-circuit any of the strips because it will not work.) A hole should then be bored exactly in the center of the small piece of fiber and fastened to the main base by meant of a wood or machine screw. The complete reverser and connections are shown in Fig. 3. If desired a metal base and body can be made to enclose the working parts. If so constructed a slot should be cut in the body for the extending handle so th« switch can be easily operated. Contributed by WALTER SELLENEIT.

HOW TO MAKE A S.T.D.P. SWITCH Here's a to Make Home-Made Snap At Left—Twisting Cables With a Bit Brace. Way OUT OF TWO S.P. KNIFE Switches. It Works Very Well, Too. At Right—Using the Spare Spark Plug as a "Test" Plug for the Auto Engine. SWITCHES. Nail a block of wood on to a base of used either as a single or double-pole TWISTING CABLES IN THE SHOP. proper size. Next procure two S. P. bat- switch. Contributed by In looking over your October, 1916, issue tery knife switches. It must be made cer- HENRY O. WUELFING. under the head of "How-to-make-it," I tain that one opens to the right and the —

642 EXECTRICAL EXPERIMENTER January. 1919

EDITED BY S. CERNSBACK

SPIRIT LAMP FROM FAN GREASE- Javclle water (solution of sodium hypo- into crystals, so filling the bottle that not a CUP. chlorit) is an ingredient of ink eradicators. drop of water will escape. Should there be A novel but efficient spirit lamp can be The solution is first applied to the ink and any hesitation at the moment of shaking, made from a fan grease-cup when cleaned a dilute solution of hydrochloric acid is drop a small crystal of the salt into the and filled with alcohol and a wick inserted. rubbed over it. The chlorin which is lib- bottle, and the effect will be instantly seen, erated is responsible for the bleaching ef- by the darting of new crystals in every fect direction- imo// Brass Contributed by ALBERT TOTH No. 4: Heat a piece of tin until the

'd/ohr fi/de coating begins to melt ; then cool quickly TEST CLIP MADE FROM BINDING in water and clean in aqua regia. The POST. surface will be found covered with beautiful crystals of the metal. contact with insulated wires For making No. 5.- Pour dilute nitric acid upon bits take an old binding post and file the thumb of tin. Dense red fumes will pass off. screw to a point. Also cut a portion of No. 6: Throw crystals of any nitrat on one side out with a hack-saw as shown in red hot coals ; they will deflagrate with the drawing. To make contact with an dense red smoke. insulated wire, simply slip the wire in the Contributed by GLENN HELWAGEN. slit in the side and force the thumb screw point thru the insulation. This saves the PERCENTAGE SOLUTIONS. time and bother of skinning the wire. It The difficulty about percentage solutions, also may be^ used as a helix clip. says Studio Light, will disappear if the Contributed by MERLE E. NANTZ. worker will always bear in mind that one FITTING A MINIATURE BULB TO STANDARD fluid ounce of water weighs 437^ grains, SOCKET. which is, of course, equivalent in weight to First we need a broken Edison bulb, a one ounce avoirdupois. It follows that if miniature lamp and some sealing wax or one-tenth that number of grains i.e., 43.75 paraffin. all grains—of any ordinary soluble chemical is simply Fill a Fan Grease Cup with Wood Then break the glass from into graduated glass Alcohol, Insert a Wick In the Hole, and You the bottom of the large lamp base. Now put a and water added Have a Serviceable Little Spirit Lamp for solder the two wires from the Edison shell to make up one fluid ounce, the result will Light Soldering to the rim and center of the miniature bulb. be a 10% solution. Heat some sealing wax and pour in around In the following table the figures are It will bum for one hour. This lamp can the shell and set aside to harden. This worked out for solutions of various be used for numerous purposes, such as attachment will be useful to anyone who strengths. If the number of grains indi- removing enamel from enameled wires, et has a socket with a snap on the side or a cated in the table are taken and sufficient cetera. A small brass tube can be easily pull-chain socket. water added to make up one fluid ounce, it soldered to the cup for the purpose of will be found that the solution has the re- Contributed bv STAN. DIRVIN. providing a blast of air and a side-wise con- quired strength. centrated fJame tip, by blowing thru the For a 1% solution take 4.37 grains tube. The upper^nd of the tube must be 5% " " 21.87 closed, and a tiny hole drilled in it—about 10% " 43.75 No. M drill. 20% " " 87.50 Contributed bv EDWIN WOLBER. 30% " 131.25 40% " 175.00 SOME INTERESTING CHEMICAL 50% " 218.75 EXPERIMENTS. When a very little dry powdered potas- HOW TO FILE SOFT METALS. sium permanganat is moistened with sul- The teeth of a file are soon filled when furic acid, brownish-green oily drops of the file is used on lead, tin, soft solder or permanganic anhydrid (Mn,OT) are formed. At Left: Standard Lamp Base Fitted to aluminum. It cannot be cleaned like the Miniature Lamp. At Right: Handy Test This compound is volatile, giving a violet Clip Made from Binding Post. wood rasp by dipping it into hot water, but vapor and is apt to decompose explosively if the file and the work are kept wet with into oxygen and manganese dioxid. Its water, there jvill be no trouble as the already oxidizing power is such that combustibles CHEMICAL EXPERIMENTS. wet particles of lead, soft solder, etc., do not like paper, ether and illuminating gas are A/o. /.• Put on a clean white plate or readily adhere to the file. set on fire by contact with it. saucer, a mixture of pulverized sugar and White phosphorous, when heated with potassium chlorat. Upon adding a few HANDY COMPUTER FOR sulfur unites with explosive violence. By drops of sulfuric acid a vivid combustion MECHANICS. using red phosphorous the action can be will ensue. By adding with the sugar a Here's the latest vest-pocket computer for controlled. The product is phosphorous few iron and steel filings, and performing electrical and mechanical men. By rotating sulfid and the kind depends upon the pro- the experiment in a dark room, or out of the cap on end it shows at a glance the size portions used. doors at night, fiery rosettes will flash thru of drill to use for taps from ^ to 2 inches. If a small piece of soditun is placed on a a rose colored flame, and produce a fine U. S. S. Pipe 'A to 3'/! inches. A. L. A. M. piece of filter paper and placed on water, effect. to 1 inch. S. A. E. to V/i inches also 15 the water is decomposed and the heat lib- No. i: Mix a teaspoonful of nitric acid small numbered sizes below 1% inches. It erated is sufficient to set fire to the sodium, with a teaspoonful of sulfuric acid; place has the advantage over blue-prints and which burns with a characteristic yellow a little turpentine in a teacup out of doors, chart that it can be easily carried in the vest- flame. and pour the mixture upon it at arm's pocket. Powdered magnesium and potassium lenRth. The turpentine will burn chloral in the proportions of 10:17 is used with almost explosive violence. in making flashlights for use in photography. No. s: Make a saturated solu- Cordite, a variet>- of smokless powder, is tion of sodium sulfate (Glauber's made by dissolving guncotton (65 parts) Salt), in warm water; pour the nitro-glycerin (30 parts) and vaseline (5 mixture in a bottle, and let it parts) m acetone. The resulting paste is stand. The salt will remain for rolled out and cut into small pieces. When months without crystallizing ; but if the acetone evaporates the homy cordite taken up, and shaken a few times, A Useful Computer for Machinists and Experimenters. . remains. the whole mass will instantly form It Shows the Size of Drill for Any Tap Instantly. January. 1919 ELECTRICAL EXPERIMENTER 643

gill IPs: fc*^.

Loose Coupler Electric Headlight A Sound Operated Dog adj ustable feature enables the con- (No. 1,276,618, issued to Carlyle B. (No. 1,276,605, issued to Overton (No. 1,279,831, issued to Christian tact member to be placed at any Campbell.) Winston.) Berger.) point upon the surface of the crys- This patent relates to an improve- An improved electric headlight for When you clap your hands- or tal desired, and the contact point ment in tuning transformers and automobiles and other machines and whistle to this "pup" he jumps out and and crystal are both enclosed. particularly to a switching arrange- pioviding a special means for shift- ing the electric light bulb with re- Motor-Driven Revolving Door spect to the reflector, whereby the (No. 1,278,145, issued to Edward bulb may be moved transversely C. Haviland.) toward and from the axis of the re- Where a revolving aoor is con- flector. A soft iron or steel collar tinuously rotated, electric current is is secured to the rear end of the being continuously consumed regard- lamp base, which serves as an arma- less of the egress or ingress of ture in cooperation with an upper people thru the door. The object and lower control electromagnet. of the present invention is to pro- These electromagnets are secured to vide a means whereby a motor for and supported by an annular ring revolving the door is only put in mounted in the lamp housing back operation when a person is passing ment by which unused portions of of the reflector. Thus the lamp thru the door. This device com- the inductance or winding are com- bulb proper may be thrown up or prises switches carried by the in- pletely cut off from the circuit, down, simply by actuating one or dividual wings of the door in prox- thereby eliminating undesired effects on the wave lengths. The arrangement shown provides for a plurality of separate coils in close inductive relation. The terminals are connected with solid and spring contacts, adapted to be separated by a revolu- of his kennel in great delight. All ble insulating disk in order to cut because of a clever arrangement of out certain coils when so desired. a simple microphone and electro- In other words, it incorporates a magnet which holds the trip retain- revoluble form of dead-ending ing the dog within the kennel, until switch. the sound produced by the clap of the hands or whistle strikes the Electrically Heated Radiator microphone. At this instant the (No. 1,276,573^ issued to James J. normal constant current thru the Kohan.) retaining electromagnet drops to a An electrically heated steam radi- comparatively low value, thus re- ator of novel desig^n in which there leasing the powerful spring which is provided a radiator of the usual kicks "Fido out the door. form, together with an electrically heated steam generator, this latter Primary Battery being very rapid and economical in (No. 1,276,754, issued to Walter operation, it is claimed. Simple and Grothe.) positive means are provided for A novel arrangement for supporting the electrode elements within a iipity to the usual hand-rails, so that they may be either consciously the other of the electromagnets, or unconsciously actuated by the throwing the light beam either far person passing thru the door. These ahead of the machine or else just switches establish electrical circuits in front of it on the ground, as to the actuating motor, but only for may be desired. such time as is necessary for the person to pass in or out of the door. Apparatus for Concentrating and Projecting Radiant Energy Radio-Telegraph Transmitter (No. 1,278,026, issued to Salvatore (No. 1,278,507, issued to Oscar C. automatically controlling the flow Salto.) Roos.) of electric current to the beater, An apparatus for the concentra- A system in which the dis- and likewise for automatically con- tion of light, heat and electric rays charge of the oscillating circuit controlling the flow of water of con- and for the projection of these rays denser may be readily controlled densation from the radiator back to in a certain desired manner. This over a wide tone range. The oper- the heating device; this automatic apparatus for concentrating and di- ation is as follows: The high- control being effected thru the me- recting light rays has for its purpose frequency generator A cannot dium of the steam pressure develop- to illuminate objects by concentrat- break down a larger gap than S ed witbin the heating device. ing light rays thereon, by means of and the arresters, therefore prevent reflectors with elliptical curvature. the discharge of the condenser C" across the gap unless they are si- Electric Shutter Trip for Cameras primary battery. The supporting multaneously broken down. They (No. 1,277,592, issued to Gilbert R. member for the electrodes consists Horton and John M. Miller.) of a flanged yoke having depending By means of this electromagnetic ends, while a suspending bolt passes actuating mechanism for camera thru a hole in the yoke and is rivet- shutters, photographs may be taken ed therein. A spool of porcelain at a considerable distance from the is arranged to be clamped against operator, such as where animals are the yoke as shown. The shank and to be photographed. The length of heads are preferably of triangular circuit over which this shutter de- shape. A perforated container vice may be operated is governed closed on all sides excepting the only by the strength of the battery top, is adapted to be clamped be- used. A push button or switch is tween the depending ends of the located at battery, the the current yoke and the ends of the clip. completing a circuit thru the small electromagnet fitted to the shutter :a Crystal Detector trip as shown. When the magnet (No. 1,277,627, issued to Thomas is actuated the shutter is opened; B. Miller.) continued pressure on the push The object to be examined or illu- A crystal detector for radio re- button will hold the shutter open. minated may be observed directly ceivers which is claimed to be ex- by placing it inside the hoHow ellip- ceptionally rugged and reliable in soid, or projected on a screen by design; also its operation is not will be simultaneously broken down means of a suitable device such as likely to be interfered with by me- 2(n—m) times a second where "n** a miscroscope or a magnifying lens. chanical jars or concussions. This and "m" represent the frequencies Thus extremely high specific lumi- of the generators A, A" respectively, nous or caloric intensities are ob- so that the tone produced in the re- tainable by concentrating emanations Cru'fkl ceiving system will be the '*beat from several sources of energy and j^ frequency of said generators. This causing them to be projected. An tone, as will be obvious, may be apparatus such as this may be used widely varied by slightly altering the as a marine searchlight or coast speed of one or ooth generators. light, or as a projector for motion This scheme will thus be seen to picture machines, automobile head- afford a very simple and flexible lights, etc. The apparatus can also electrical substitute for various me- be used for concentrating heat radi- T'oif*^. chanical devices such as the "tone ations. wheel," the rotating spark gap. etc. — —

644 ELECTRICAL EXPERIMENTER January. 1919

MJihh^^ ttmAmzJmdf -?>'•

Our Amateur Laboratory Contest is open all readers, whether subscribers . . - -.. - to -. or-- not. The photos are for . , -r— judged best arrangement and etSciency of the apparatus. 10 increase the interest ot this department we make it a rule not to publish photos of apparatus unaccompanied by that of the owner. Dark photos preferred to Iight-toned ones. We pay $3.00 prize each month for the best photo. Address the Editor, "With the Amateurs" Dept

''Amateur Electrical Laboratory" Contest THIS MONTH'S $3.00 PRIZE WINNER—ALFRED STAGEY HEREWITH are photographs of my laboratory. On the large table in the center of the room may be seen the radio outfit which was assembled in its original place to take this photograph. When set up it was used with an aerial one hundred and fifty feet high, one hundred feet long, with four stranded wires placed three feet apart. The transmitting set consists of a 5^ K. W. transformer, condenser, rotary gap, oscillation transformer, aerial inductance, aerial condensers, and hot-wire meter, keys, etc., also a Poulsen arc and transmitter for radiotelephony. For receiving, I have receiving transformers, variable condensers, fixt condensers, audion, loading coils, Ferron, Galena, and Silicon detectors, two pairs of 'phones, etc. On the experimental table to the left of the radio table may be seen Tesia, audion, step-up and step-down transformers, meters, batteries of different types, motors, generators, telegraph and telephone instruments, condensers, measuring instruments and other electrical apparatus. To the right of this apparatus may be seen the two switch-boards containing circuit breakers, switches, and rheostats for controlling various instruments. To the right of the switch-board may be seen the work-bench for building and repairing instruments.' To the right of work-bench, chemicals, elements, retorts, graduates, flasks, hydrometers, thermometers, ad infimtum. To the right of this bench will be seen another bench used for the manufacture of chemicals such as bromin, chlorin, etc. Next may be seen the stock-room and dark-room used for photo developing and printing. I have a book-shelf containing over one hundred and fifty chemical and electrical books. This laboratory is the result of ten years' hard work assisted by the famous "Electrical Experimenter" and "Modern Electrics." Alfred Stacey, Hamilton, Ontario, Canada.

HONORABLE MENTION (1 Year's Subscription to the ''ELECTRICAL EXPERIMENTER'') GERALD DITTMAN PRESENT herewith photograph of myself and two of my laboratory. I am eighteen years old and have had my laboratory for about a year. I I have a great number of chemicals which I use for testing foods and for mixing up different solutions to see what effect they have on electricity. I have made an arc light which furnishes all my illumination. I use an ammeter to show how much current I am drawing and tn that way save fuses, because when the pointer approaches ten amperes, I know a fuse will blow and I can shut it off in time. I also have a number of motors, a transformer, spark coils, condensers, Leyden jars and other instruments which I use for various experimental purposes. Gerald Dittman, Chicago, III. January, 1919 ELECTRICAL EXPERIMENTER 645 Phoney Patents Under tbi* heading are pubUsht electrical or mechanical ideas which you haven't a smell of a Patent yet. After they have allowed tha our clever inventors, for reasons best known to themselves, have as yet Patent, you must pay another $20.00 as a final fea. That's $40,001 W« not patented. We furthermore call attention to our celebrated Phoney PAY YOU $3.00 and grant you a Phoney Patent in the bargain, so application, Patent Ofiizi for the relief of all suffering daffy inventors in this country you save $43.0011 When sending in your Phoney Patent as well as for the entire universe. be sure that it is as daffy as a lovesick bat. The dafiier, the better. We are revolutionizing the Patent business and OFFER YOU THREE Simple sketches and short descriptions will help our staff of Phoney DOLLARS (*3.00) FOR THE BEST PATENT. If you take your Phoney Patent Examiners to issue a Phoney Patent on your Invention in > Patent to Washington, they charge you $20.00 for the initial fee and then jiffy.

^OJeG/?N PIPES

P/Pf FPOM P/G5 CHFPF7- F6^Jem/^5S JU/C£ SF/e TO o/^- FO/? £iFcr/eo c peop^/^ :^Z>//6PA^FY 3o/?/eo \i-ow/rEY 60/9eD WIPES

Prize winner: WEEWEEEPIGORGAN. Take one gross pigs fresh and lusty, assort according to musical scale, put each In soundproof chamber, attach tails to electromagnetic claws operated by keyboard. Pigs run on endless belts furnishing power for organ. Depressino keys on keyboard pinches pigs' tails. Pig sings weee—weeeee—weee, as long as key Is pressed. Don't use old sows. They sow discord. French airs go well on this organ due to the oul, oull Inventor; Paul Gaugewere, Bethlehem, Pa.

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MIMOSA ELECTRICUS AUTOM ATICUSS. Sun. More Sun. Heat. Dry. Draught. Plant. Droops. A, B, UP. Contacts. Kiss. Bliss. Juice. Motor Battery. H,0. Hose. Spurts. HjO. Drops. Rain. Plant. Branches, Newlife. Upshego. A. B. Down. Contacts. DIVORCE. Rain. MX. Simple. Fix. See? Oul. OulII Inventor: Frank Truka, 280 Woolsey Ave., Astoria, L. I. : : : : :

646 ELECTRICAL EXPERIMENTER January. 1919 HE RRAC UE

The "Oracle" Is for the sole benefit of all electrical experimenters. Questions will be answered here for the benefit of all, but only matter of sufBcient interest will be publisht. Rules under which questions wlU be answered: 1. Only three questions can be submitted to be answered. 2. Only one side of sheet to be written on; matter must be typewritten or else written In Ink, no penciled matter considered. 3. Sketches, diagrams, etc., must be on separate sheets. Questions addrest to this department cannot he answered by mail free of charge. 4. If a quick answer is desired by mail, a nominal charge of 25 cents is m.ide 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.

FIRING TWO FLASH-LIGHT POW- varj'ing the speed. Again, by means of an means of suitable switches or by varying DER PANS SIMULTANEOUSLY. induction regulator which consists of a pri- the current by a suitable rheostat connected (970) Fred Wheeler, Gait, Ont., Can., mary and secondary winding, having an in the respective legs of the wound rotor wants to know iron core with one of the windings so ar- circuits. This last method also applies to ranged as to allow of being varied thru 180 the single-phase system, wherein the cur- Q. 1. How to fire two or more flashlight pans simultaneously. magnetic degrees. rent is varied by means of a rheostat. A. 1. For firing flash-light powder at The above methods are really best for single-phase service, while the following LOOSE COUPLER AND DIS- method is very good for the three-phase TRIBUTED CAPACITY. Ponder service : In this method the speed can be (973) C. W. Opert, Freeport, 111., wishes Tnesegops ifx>u/d varied by changing the of poles 'A? smoi/aadiustabia number to know of the motor connected in the circuit by Q. 1. Several points about making a loose coupler transformer for radio receiving circuits. ± illllliilllll A. 1. In constructing a loose coupler, B ODD PHOTOS WANTED AT the best way to take the taps off is as fol- lot m $1.00 EACHia lows: At the required part of the coil, punch a hole in the cardboard tube and g Now is the time to make your ^^ I Coil bring about 18 inches of wire right thru Hililili- ^ Kodak pay for itself in a real practi- this hole by looping the wire, and then H cal way. We are after interestinc/ pushing it thru. All that remains to be ptwtographs of out-of-the-ordinary g done now is to continue winding the coil Firing Two Flash-Llght Powder Pans at m electrical, radio and scientific siib- until all the taps have been made. Once by Means of Spark Coil. Several = jects and are willing to pay $1.00 cash Flashes May Be Ignited at Once. provide coils with dead-end switches for every one we can use. Please We B in order to get rid of the distributed ca- two places simultaneously, we refer you H bear in mind that for half-tone re- pacity. Distributed capacity is the capacity to arrangement as per diagram. Use a production in a magazine, a photo- J which e.xists between the turns of a helical spark coil and battery as indicated in dia- graph should be particularly sharp ^ coil, and for your benefit we refer you to gram. Wire the two or more flash pans in M and clear. Of course, if a subject an extensive article on this subject which series. Keep the spark gap in each pan ^ happens to interest us particularly was printed in the May, 1917, issue of this small 1/16" gap is sufficient. M well, we can have the photo re- — journal. touched. For the general run of sub- HOW TO TELL DYNAMO I jects, however, it does not pay to go TESLA COIL FOR 2-INCH SPARK POLARITY. g to such expense. Therefore, please COIL. take pains to properly and (971) Paul Miles, Chicago, 111., inquires: = focus ex- (974) R. Conover, New York, N. Y.,

your pictures. It • Q. 1. How can the positive terminal of a ^ pose often happens inquires of "The Oracle" that a really mediocre subject well small D. C. dynamo be determined? M \ Q. 1. For data on a Tesla coil suitable photographed wins ^ A. 1. Off-hand we cannot tell you which S approval over an for use on a 2-inch spark coil as an exciter. excellent subject poorly photographed. ' is the positive brush. However, we advise g A. 1. The ordinary Tesla coil, especially don't send plate '. you to make the following test: In a 50% H And us or Mm "nega- designed to work with a spark up to 2 lives" ; send unmounted or solution of salt water put two wires con- = mounted \ inches on the primary side will do, and

"prints", preferably a light and dark \ nected to the dynamo, and note from which m is briefly described as follows. The pri- wire the most bubbles come off. This is M one. mary should consist of 14 turns No. 10

'^s to \ the negative wire. m what to photograph: Well, solid, rubber-covered copper wire in one that's hard for us to say. leave A 4-volt dynamo will give about 3 am- g We , layer on a spool A'/i inches in diameter, that up to you, and every reader peres. However, much depends upon the g now i while the secondary consists of a coil 2^ has the opportunity to become a re- condition of the brushes (contact, pres- J \ inches in diameter and 12 inches long, etc.), condition bat- porter of the latest things in the realm sure, and the of the J \ wound its full length with a layer No. 28 teries. We would advise you to refer to m of Electricity, Radio and Science. enamel wire. But, — "Lessons in Practical Electricity and Mag- H please remember it's the "odd, This size of Tesla coil can be furnished netism," by Swoope, which can be pur- g novel or practical stunts" that ive are by the leading companies who advertise interested in. Every chased thru our Book Department for $2.25, photo submitted in our magazine. It is best to use two one- should postpaid. B be accompanied by a brief de- pint Leyden jars connected in parallel or M scription of 100 to 150 words. Give SPEED CONTROL OF A.C. — a one-quart Leyden jar. MOTORS. B the "facts" don't worry about the The construction for a glass plate con- = style. We'll attend to that. Enclose (972) Hugh McPherson, Borden, Sask., denser for the above Tesla coil is as fol- stamps if photos are to be returned Can., asks I lows : Procure five glass plates 6x7x1/16" m and place a piece of cardboard in the Q. 1. How can I control the speed of a and four pieces of tin-foil 5x6 inches. The envelope with them to 30 H.P. AC. 3-phase motor? = prevent muti- tin-foil should be placed between the five lation. Look around your town and A. 1. The speed of the 30 H.P. A.C. 3- g plates so that two ends of the tin-foil pro- see what you can find that's phase motor can be regulated in several m interest- trude from the sides of the glass. The ways, some of the best of which are as size of the spark obtained from the above Address photos to—Editor follows m "Odd Tesla coil will be about J4 to I '"ch and Photos", Electrical Experimenter, The voltage applied to the motor is va- m can be taken thru the body without any 233 Fulton .Street. ried by a transformer from which several B New York City. harm. taps are brought out to a controller, thereby iiniiiiiiiiiiiiiiiiijiiiiii (Continued on page 648) .

January. 1919 ELECTRICAL EXPERIMENTER 647

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Send for this free lesson which explains the Chicago "Tech" method of teaching Draftsmanship by mail. Positions at big salaries are now waiting for competent men. The call of men to the war has left vacancies everywhere. Even draftsmen of limited training and experience are snapped up and paid good salaries. If you are dissatisfied with your opportunities, learn Draftsman- ship. Chicago "Tech" will train you in the most practical way in *OCi1^ •^i^'*^^;-rsc'>'^^"?^'>.w the shortest time. Mail the coupon today and let us tell you about the Chicago "Tech" method. This free lesson will show you how ""^"oV^^l well equipped you are to follow Draftsmanship. Enroll in the course Coi^ ^^Cp only if you decide that you can take it up to advantage. No cost, no obligation on you to make this investigation.

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Hold your present position while training. Our experts will instruct you by mail. Only your spare time is required. You are directly under practical draftsmen and engineers. You are taught exactly the work required in the drafting rooms of big con- cerns. No time to put in on unnecessary studies. This means thorough instruction and early graduation.

Auto and $2522 to $10022 a Week Gas Engine Course Draftsmen earn good salaries in normal times. They command extra All about automobile mecbanlsm —its construction, operation and and the tremendous work to be done after the war will EEPAIR—taught by mall. You high salaries now— train directly under the Chicago intensive demand for good men. your spare "Tech" automobile experta. Splen- bring a permanent and Make did opportunities open now. time count now for a higher salary and a better position. Learn All This In Spare Time Easy Payments FREE Instruments the Automobile. Principles of student of the Chicago Every point made clear about the The fees for Chicago "Tech" Every "Tech" Course principleB of propulsion, pow- basic irt Draftsmanship receives this set of instru- er, transmisglon sygtems. etc., etc. Courses are very moderate—and Gasoline Engines. All about the ments, or a cash credit in case he already has a A complete course you can pay on easy terms. And different types. set. These instru- in gas enilne construction, opera- also—you obtain in a few months tion and repair. ments are of the same Power Plants and Transmis- what it would take several years to 4- sizes as sions. Application of power, by acquire by ordinary methods. You make and 6-8-12 cylinder engines. Types of used by high salaried clutches. Gears, Drives, Axles, eto. can get an early start. You are Carburetors and Fuel Supply experts in drafting methods demon- soon ready to take a paying position Systems. All rooms of factories, strated. Fuel values. How to test. and to quickly get back the cost of Gasoline and air mliturea. Bepi- shops, railroads, etc. lation, etc.. etc., etc. your course. Lubrication and CooltnB. All You use them while about oils and how to teat them. learning then take Splash and drotilatlng systems. — Operation In different cars ex- Send the Coupon them right into your plained. DlagramB, etc., etc.. etc. The sooner you are prepared the sooner you Batteries. Electrical principles practical work. explained. Instructive diagrams of will be holding a job that pays a large salary wiring and connections, etc., etc. and opens the way to advancement. Many Magneto Ignition. Principles executives, general managers and superinten- operation of various and practical dents began as draftsmen. r CoUegey types and systems with diagrams. Chicago Technical ar- first and Generation of current. Field, Other institutions ask you to pay — 145 Chicago "Tech" Building, Chicago mature, high and low tension, all then to find out later how well qualified you explained. Complete In every point. are for this profession. We send the free les- Starting and Lighting Systems. without obligation to me, please send me your FREE Teat Lesson obligation at All modem methods. Starters— son first and place you under no and other Interesting literature covering the subject Indicated below. sparb, mechanical, air. acetylene, all. Discover your qualifications before you Mark X opposite worb in which you are specially interested. electric, battery—shown In detail pay anything. with dlagrama and full explana- Architectural Drafting 1 Plan Reading—Builders will bring the Test Lesson, free. Drafting Plan tlona. Charging. Motor and gen- The coupon Machine [ Reading—Shop Men ' ' eraor adjustments, etc., etc. Also information about the profession of Electrical Drafting Estimating Drafting Surveying Draftsmanship and detailed facta about Chi- Structural Sheet Metal Drafting Map Drafting methods, the fees, terms, etc. Know How to Fix Troubles cago "Tech" Builders' Course Autoa & Gaa Enfftnea Most complete Instruction In Mark with X the branch you are interested in auto repair work. for if which course to take, Equips you —or in doubt about Name . high pay or to start a business. Big write a letter stating facts about yoursclf_ and demand for trained repair men. asking our advice which will be freely given. Address X WRITE Mail either the coupon or the letter today. State Send the coupon and get oata- city log and all Information—now. College or Home StudyT State which.

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648 ELECTRICAL EXPERIMENTER January, 1919

THE ORACLE. order to get the charge, it is necessary to hold the discharger (Continued from page 646) as shown, and a con- Mesco Telegraph tinuous discharge will flow across the two RECORDING SPEECH knobs. The quality of the spark is the ON A MOV- same whether charged by a static machine ING IRON Practice Set WIRE. or Leyden jar, except that in the case of a static machine the spark will sometimes (975) Miss Clara B. Griffin, Carthage, leap several inches, while jar charged For Learning Telegraph Codes IlL writes this Department: the with a spark coil will only leap an eighth Q. 1. Can an instrument known as the Telegraphone record speech? or one-quarter of an inch, and in extreme cases one-half inch. A. 1. Relative to your inquiry regarding the Telegraphone, an instrument invented by Valdemar Poulsen of Denmark, we are DOES A PERSON WEIGH MORE pleased to state the following AFTER EATING. Querist, York City, inquires This instrument will record speech on a (977) New 1. a person weigh more after thin steel wire by recording the fluctuations Q. Does drinking say, 25 glasses of beer, or eating of the magnetic lines of force set up thru 10 lbs. of beefsteak (as often happens at a set of magnet coils. A full description beefsteak eating contests), or will their of this machine was given by Samuel Cohen weight remain the same? "A" says they in the June, 1915, issue of this Journal will weigh the same ; "fi" says their weight an article also appeared in a back issue de- The Practice Set comprises a regular tele- will increase in exact accordance with the gni>h kej, without circuit breaker, & special scribing iron disc tjTJe of Telegraphone de- amount of food or drink taken into the high pitch buzzer, one cell Red Seal Dry signed as a dictating machine for business stomach. Battery, and four feet of green silk covered offices. flexible cord. A. 1. This is an interesting question and The key and buzzer are mounted on a one that has been asked hundreds, even highly finished wood base, and three nickel CHARGING LEYDEN JARS. plated binding posts are so connected that the thousands, of times. The Editor of this set may be used for five different puriKises. (976) Mr. B. firewater, Dedham, Mass., column recollects that the usual answer by List Ko. Price asks: the man in the street is to the eflfect that 342 Telegraph Practice Set» with Bat- 1. Different ways to charge tery and Cord $3.24 Q. Leyden he will weigh exactly the same. He will, Weighs 4 lbs. packed. jars. eventually, but—well, listen to the learned Price does not Include postage. A. 1. We are C*"^*''** f^"^5 Set fof iMinin! the Mof je giving a sketch IWFCr^O -t- Fi^. 1 -2- 1 Vunl ud AiiSbk Cades herewith how to charge the ordinary Leyden jar by means of a static machine. The best way is to hold the jar in the hand [ilher hold jar in nand or connect the outer coating lo let and sparks eartt) -water pipe etc. from one of the balls of the static which Tlilj oatflt Is the only reliable Instrument machine jump over will CDkble student^ to became proflcieot. operators In Ihe U. 8. Nav*! Seirloe. because U la equipped to the central ball with a bnuer and miniature lamp enabUns the user to master both the visual and audible siffnals of the Leyden jar. quick It. At first the sparks Lilt No. 62— Praetlee Set with Red Seal Bat- tery and Cord $4.05 will jump fast, WelBha4 Iba. packed. Price does not Include pottage. then as the jar becomes charged Discharger for the Edition of Send New they will grow Our Catalog W28 smaller and small- fartt! er, finally hardly It It Boektl tize. contalni 2*8 papfla, with over 1.000 lltuttratlont. and deacrlbet In plain, clear any sparks will Ctiaraino Leuden Jars from Static Mach languaa* all abeut Belli, Puih Buttont, Batteries, at all. Telephone and Telegraph Material. Electric Toys. jump This Bumiar and Fire Alarn Contrlraneet. Electrlo Call shows that the Belli. Electric Alarm Clockt, Medical Batteries, Leyden jar is fully Motor Boat Horni, Electrlealty Heated Apparatus. -Primary -Hmmmmt' Battery Connecton. Swttchei. Battery Gauaee, charged. It can Wireless Telefraph Instruments. Ignition Supplies, lecondary of ind. coil etc. then be discharged by means of the Send for the Catalog Now ordinary discharger as shown in Manhattan Electrical Fig. 2. Supply Co., Inc. The important NEW YORK: CHICAGO: ST. LOUIS: part to remember is 17 Park Place 114 8. Wells 8t. 1106 Pine St. that Saa Franolsoo Office: 604 Mission St. not every glass can be used for Leyden jars. Here LeyOen jar MECHANICALLY RIGHT—A REAL LATHE is where many an Fig. 5 A Regular lathe, not a toy experimenter is dis- appointed. Only Choroina Leuden Jon from inauction Coils potash glass can be Varlou* Ways In Which to Charge Leyden Jar Condensers from Static charged — all the Machines and Induction Colls. other varieties.sucb as Hint and lead glass, "leak"—it being im- arguments put up by three well-known New Swing 4 Ini^ee. 11 Inches Iwtween ceo- possible to sustain a charge for even one York medical authorities. ten. 17 Inches toul length. Net weight second if such glass is used in the Leyden Says the 9 Iba. Bhlpplnc weight 13 lbs. New York Medical Journal: The bed of this lathe Is machined. jar. If no potash glass is procurable, an In the case of eating, say, a pound of meat Workmanship Is first class throughout. Lathe comes equipped with wood tura- ordinary phonograph disc coated on both or drinking a pint of water, the weight of int chuck. Lathe can be fitted with 3 sides with tinfoil will answer. Good re- the human being is increased immediately toco fa.* plat*- and drill chuck as ipecia) equipment. Ordfr on* today. Price M-SO cash with order. sults can also be had by using hard rubber aftef. In the course of two or three hours, SYPHER MFG. CO, DEPT. C, TOLEDO, OHIO sheeting. This material does not "leak." however, the weight will return to normal, It is not possible to charge Leyden jar due to evaporation of moisture from the Feldman's "Geyser" by means of spark coils in the way the jars lungs and pores of the skin, also to digestion. are charged with a static machine. In other Dr. Sinclair Tousey, the well-known New Electric Water Heater words, the jars can never be fully charged York medical authority, says:' Immediately and kept standing for a few seconds and after eating one pound of meat, the person IriMtantaneout Hot Water subsequently discharged as if they had been in question would have less than one pound FELDMAN MFG. charged with the static machine. The added to his weight. Owing to the in- CO. method to charge the jars with a spark coil creased evaporation of moisture from the ISOO Time. Bldg. New York City is shown in our illustration. Fig. 3. In (Continued on page 650)

You benefit by mentioninff the "Electrical Experimenter" when writing to advertisers. January, 1919 ELECTRICAL EXPERIMENTER 649 Lecirn Electricit

Ji>. w

.f'^i'. rJf ft 0: ifttfr. r^} P'-jt

inthe Great Shops of

PRACTICAL COYNE^i^^*^ — -^•rf FINISH IN Trade and Engineering Schools 3 MONTHS **^»«-'INSTRUCTIONAXV-' M. * V^ AV/1^ rk-_^ oi c^ in: :. Dept. 21, 39-51ia c Illinois— St.,c» Chicago, Hi.

Thousands of skilled Electricians are needed.- The demand is becoming more urgent every scarcity day. The Government is employing every one they can get which is causing a great throughout the country and big salaries are being paid everywhere. Right now is your big opportunity. Make up your mind now to prepare for one of these big jobs and then get here as quick as you can for your training. Earn $100.00 To $300.00 A Month In the Electrical business. Come here where you will be trained in these great $100,000 shops. Experts show you everything and ^^^^^^^^K^F^Y i you learn right on the actual apparatus. You work on ^.^^^^^^t^^^^^m M I everything from the simple bell to the mighty motors, generators, electric locomotives, dyna I mos, switchboards, power plants, every- ^^^ thing to make you a master electri- '^^^_^^0\^\ I War Demands Have cian. We have thousands of sue- Taken Thousands of Men cessful graduates. Just as soon as you have finished from this Profession. Men we assist you to a Must be Trained to Fill their Places. good position. We now have more Prepare Now for a Big Paying Position. positions than These courses are thorough, short and practical. All instruction given on we can fill. the actual equipment. Each man is trained individually and stays until thor- Think oughly trained. Start any time—day and evening classes. of it. Our graduates are in great demand. We are continually receiving letters, telegrams, and telephone calls from contractors, manufacturing firms, etc., seeking our graduates to fill responsible positions. We have now more positions than we can fill and the demand is steadily growing. Every comfort is given our students while here. They live in comfortable homes in the most beautiful section of Chicago—on the lake.

The War is Over— Yes I LEARN DRAFTING Skilled but the men "over there" will not be back Draftsmen are always in demand. Our courses are for months perhaps years, for their work thorough—short—practical, preparing a man fully — to hold a position of responsibility. "over there" isn't over. And so you, and thou- We have more positions than we can fill. also have thorough sands more must fill up the gap now that the We practical courses absence of these brave workers has made in the in Plumbing and Heating, Motion Picture Operating Bricklaying. ranks of skilled labor. Trained Electricians are and needed more, perhaps, than any other class of men. EARN YOUR The sudden ending of the war has caused the big indus- WAY tries to start up work sooner than any of us expected and Many students earn their living %^HH ^H ^B I^H ^H expenses by doing a little in consequence the Manufacturers are Calling for Trained work in their spare time. Our a COYNE TRADE AND Men, and we are training men as fast as we can to meet employment dept. fur- ENGINEERING SCHOOLS these urgent calls. You are needed. Young Man, now! nishes these poiitiont ^ vithout charge. ^ Dept. 21t 39-51 E. Illinois St. Don't wait. Don't put it off. Get in touch with us Today. Chicaoo, III. Get ready to join the great "Peace Army" here at home. Your country calls. Again we say, prepare to serve your Please send at once your big Free country! We'll make a trained electrician of you in three Book— I am Interested in months! Let's go! [ ] Electricity [ ] Draftino [ ] Plumbing

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650 ELECTRICAL EXPERIMENTER January, 1919

THE ORACLE. , suppose, would be of the closed core type. (Continued from page 648) Please give dimensions of core, size, num- TABLETS ber of turns, and weight of wire required pores of the skin, also from the lungs, this for primary. What kind, size, number of FOR slight difference would occur immediately. turns of wire required for secondary? But in two or three hours, due to the fore- A. 1. We give below data for construct- Grippe going causes, also digestion, the weight will ing the transformer in question gradually decrease to normal. Data for 2 K. W. 150 amp. 13.3 volt Cold Dr. William Benham Snow, of New York secondary "pipe thawing" transformer, for one of the leading American electro- in the operation on 110 volt, 25 to 30 cycle A. C. therapeutists and medical men, states ; The Core Data : —The sheet iron core should Head increase of weight in the human being after measure about 17}/$ inches ir. length by eating, say, one pound of meat varies 8^ inches in width outside dimensions, its Headaches greatly. In some instances there is no in- thickness and breadth should be 3 inches, i raise at all; while in others there is a or, in other words, 3 inches square. Both Neuralgias slight (but never the full weight) increase, of the longer legs of the core should be all depending upon the individual's respira- Spanish Influenza thoroly insulated with five to six layers of tory and digestive organs. In the case of oiled linen or Empire cloth, well shellacked. Women's Aches and Ills water, the full weight of the water is added Primary Winding : This may consist of to the person's weight, but within a very — Rheumatic and Sciatic Pains 244 turns of No. 9 B. S. gage D. C. C. short time after the weight will rapidly & copper magnet wire wound in even layers Your Druggist for -K T::olels decrease to normal. Ask A on one of the long legs of the core. iThis It has been a widespread and popular idea Sold in Convenient Pocket Packages will require about 2 pounds. that if a person were to lie on his back Secondary Winding : The secondary coil and hold his breath that he could be lifted — Small to delivery 150 Amp. and 13.3 volts at full Size Dozen Size with two fingers. This has been done by load comprise 31 turns hypnotism, but not otherwise. may of No. 0, B. & lOc S. gage D. C. C. copper magnet wire, or if this is not convenient, owing to its large ELECTROLYTIC RECTIFIER. size, you may wind on simultaneously two See Monogram Jl^ on the Qenuine Nc. 3 B. & S. gage D. C. C. conductors (978) H. H. Mosehauer, Wortendyke, The Antikamnia Company side by side, or four No. 6 B. & S. gagf. Remedy N. writes: St. Louis, Mo. J., D. C. C. conductors. The terminals of the Q. 1. I have made a small Electrolytic separate wires, if a multiple winding is used, Rectifier for charging storage batteries. are joined together so as to connect air the This rectifier built instructions was from wires on parallel. in the Scientific American Supplement No. The efficiency of this size of transformer HOTEL ST. JAMES 1644. According to the instructions, the is about 95 per cent with respect to the liquid consists of one pound of crystalized Times Square* New York Citv watts input at the primary and the watts Ju^toff Br.'Hdway at 100-11.'? West St. orthophosfate I per, jar). 45lh sodium output at the secondary BlocU

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January. 1919 ELECTRICAL EXPERIMENTER 651

RADIO-TELEPHONE GUIDED U. S. FLYERS MANY MILES AWAY. {Continued from page 629) require amplifying more than from ten to fifteen times. Fig. 3 shows a new form of oxid filament tubular audion as supplied on U. S. Army and Navy sets. This bulb is provided with a special base, making it very convenient for attachment or replacement, and tests made with this bulb show the life to be about five thousand hours. Fig. 4 shows an improved form of audion control panel. A number of new radio engineering features are incorporated in this apparatus, including deeply grooved, insulating terminal blocks which carry the binding posts. Integrating condenser switches are employed for regulating the WITHOUT training you are a diamond in capacity of the bridge and stopping condensers. The ammeter at the right of the the rough. You can't make the most of panel indicates the filament current at all your natural ability. Your real value is times. A special form of grafite potentiometer is mounted just below the filament hidden—always will be until you cut away the rough spots and polish up with practical training. That's all you have to do to put yourself in the position where you want to be —and where you rightly belong. There is no secret to success. It is just a question of mentally equipping yourself with practical training. You have the same chance as the "other fellow" —if you train. What are you going to do? Why Not Get a Better Jobl What would it mean to you if your training can you capitalize on your salary was doubled tomorrow? What natural ability. If you can get what you would $5.00, $10.00 or $20.00 more a are now earning without training, think week enable you to do ? It would mean what you could make with it. You have a whole lot more pleasure in life — a a lifetime of work ahead of you — so lot more satisfaction, wouldn't it. Then why not put in your time in congenial, why not get it? You can! It is not profitable work. Thousands of Ameri- impossible or even a hard task. It is can School Students will tell you it pays simply a matter of fitting yourself for to train. Let us send you some proof of the position and pay you want. Only by what our training has done for others. Wonderful Opportunities Fig. 3. New Form of Oxid Filament Audion as Supplied on U. S. Army and Navy Radio Sets. Await Yrained Workers

If you are untrained, take a look into share. America must also catch up current. ammeter to regulate the wing the future. Now that the war is won, with time lost in its own industrial ac- Fig. capacity osciUion S shows a large there is a period of reconstruction com- tivities. If you want to share in the a bulb and control instruments mounted on ing which will mean unparalleled oppor- prosperous times ahead you can do it. radio-telegraphic self-supporting panel for tunity for men who can think and act Get busy— now— and fit yourself with transmission. The bulb is mounted between for themselves— trained men. The war- practical instruction that is guaranteed upper and lower rings of heavy, rubber- torn countries of Europe must be re- to satisfy you, and, therefore, guaran- covered wire. The loading coil switch for constructed and America must do its teed to make you make good. varying the antenna wave length is mounted in die upper left hand corner of the panel. Terminals for the Morse telegraph key are TKAININOTHE KEY TO SUCCESS fitted at the bottom of the panel. A radi- Do Yourself PLEASE SEND ME BOOKLET AND ation hot-wire ammeter is seen at the left TELL ME HOW I CAN FIT MYSELF FOR THE POSITION MARKED X of the switchboard, while a three-pole a Favor ...High School Graduate Lawyer switch controlling the filament and wing ...Electrical Engineer Business Manager current appears at the right. The neces- Make up your mind today to fit your- ..Eleo. Light & Power Supt Certified Public Accountant sary condensers and auxiliary apparata are self for a more congenial position Hydroelectric Engineer Accountant and Auditor Telephone Engineer Bookkeeper compactly mounted on the back of the and bigger pay. You can do this . Telegraph Engineer Stenographer panel. devote a part of easy— if you will Wireless Operator . Fire Insurance Expert A ^ K. W. oscillion is good for your spare time to study. Keep on earn- Art-'hitLct Sanitary Engineer . .Building Contractor Master Plumber ISO miles radiophone transmission over ing while you're learning. Check and Civil Engineer Heating and Vent. Engineer water, or 250 miles radio-telegraph signal- mail the Coupon for Big Free Bulletin ..Structural Engineer Automobile Engineer ling over water. A 1 K. W. outfit has a and details of Money-Back Guarantee. ...Mechanical Engineer Automobile Repairman ...Shop Superintendent Airplane Mechanic range of 200 miles radiophone or 300 miles Coarse ...Steam Engineer . .General Education radio-telegraph over water. A 2 K. W. American School ...Draftsman and Designer Common School Branches will talk 300 miles or telegraph 400 miles of Correspondence water. These greatly over ranges can be Depl. G-7441 increased by the use of two to six stage audion amplifiers. The six stage audion Chicaeor U. S. A. amplifier has an amplifying factor of one million times.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 632 ELECTRICAL EXPERIMENTER January. 1919

SALT FROM THE SEA BY ELEC- WHY DON'T YOU GET AN TRICITY. intnnnOT! :t_^^^i''-. AUTO-WHEEL? A company is about to start the exploi- tation on a large scale of for pELLOWS who know wiU tell you a method ^ that the Auto-Wheel Coaster and extracting salt from sea water. The undertaking is being backed up by a number of the Auto-Wheel Convertible Roadster EXPERIMENTAL STUDIES IN are the best wagons ever built tor speed and men of exceptional standing. The process ELEC- strength. V^heels have roller bearings, steel is due to Professor Helland Hansen, and TRICITY AND MAGNETISM, by axles and tires, and the spokes are oval, like the venture is backed It Prof. Francis E. Nipher. Publisht by an auto. by $5,000,000. will in all probability be found expedient to P. Blakiston's Son & Co., Philadelphia, Send For Free Felt Pennant erect several works along the coast of Nor- Pa. 72 Pages, size 9H x inches, il- Write us names of three 6H coaster v.'agon deal- lustrated, cloth bound. ers and we'll send you a beautiful Felt Pen- way as more electric energv' becomes avail- Price $1.25. nant will FREE. We also tell you how to able. The comparatively large capital is The student of electricity and magnetism will find organize a CoasterClub. It'sgreatfiin. Each principally necessary on account of the many novel, new and decidedly interesting experi- member receives a cap and the captain a ments described in this work. The author is well special cap. "Write today. large plant needed, pumping stations, etc., known in scientific circles and of very high stand- absorbing the bulk of the power ; the pro- BUFFALO SLED COMPANY ing. Furthermore, what he has to say to us in this duction of the salt itself only requires a presentation is of more than ordinary interest. i63Schenck - Street N. Tonawanda, N, Y, Some very interesting photographs of sparks and (In Canada: small amount of energy and is consequently tYeston. Ont.) spark shadows are given \fith some new theories cheap. As to the location of the new fac- as to their meaning: causes of local magnetic tories, no definite decision has been ar- storms; the effect of "wind'' on magnetism; and also the effect of "clouds" on the magnetic needle. rived at. but Stavanger has been mentioned These effects are indeed wonderful, and so new as as a likely place for the first factory, and to demand the attention of every earnest electrical the Giaam fjord for fhe second. student. Professor Nipher has performed some very interesting experiments in the laboratory and also in the field along these lines, and if vou wish to A MELODIOUS PHONOGRAPHIC read something refreshingly new in tne realm of experimental electricity and magnetism, then you REPRODUCER. should by all means study this excellent and clearly written explanation of these little known scientific phenomena. By Frank C. Perkins. The accompanying illustrations show the ALTERNATING CURRENT: THEORY, details of construction of a new phono- PRACTISE AND DIAGRAMS, by graphic reproducer, developed at Milwau- Horstmann and Tousley. Cloth covers, kee, Wis., which it is said "Humanizes a 296 pages, 173 illustrations, size tyi x Talking Machine". It is claimed that this ' 4"^ inches. Price $1.00. Publisht by (£_ reproducer plays perfectly all disc rec- Frederick J. Drake & Company, Chicago, ord selections, even the subtle tones of the 111. instrumental accompaniments and prevents One of the well-known Horstmann and Tousley practical handbooks for electrical men, giving the theory and practice of this branch of electrical engineering so that the non-mathematical student can learn the exact meanine of the various terms used. Build and Fly The work starts with tne generation of alternating currents and discusses inductance, capacity and re- Your Own sistance and their effect on the voltage and current in alternating current circuits. Next we find an interesting discussion on impedance, watllesa Training Plane current, and skin effect. Other interesting chapters treat on the calculation of power in A C. circuits; transformers^ the Aviation. Train yourselT In theory and construction of transformers and how Be an Amateur Aviator with an in lighting Aeroplane of your own. Learn they are connected and distribution cir- how Aeroplane! are built; learn cuits; alternating-current generators, their theory the principles of construction. and construction; A. C. motors, including the syn- tpcratlon and control. We aell chronous motor and its characteristics; synchro- Scale Draw- IDEAL Accurate nous converters, their theoretical and practical op- ings, and BulldlriR and Flying Inatructlons which show you eration; the split-pole and also inverted converters; how to build a perfect Model A. C. to D. C. rectifiers of various types; including Aeroplane. 3 ft. size, that electrolytic and vibrating rectifiers; potential regu- will rise from the ground by lators; measuring instruments for A. C. work, in- lis own power and fly like a cluding synchroscopes and power-factor meters, big one. Send now for the Drawings and Instructions for with numerous tables for the calculation of A. C. the one you want to build. circuits for different frequencies and voltages. A in Drawtngs and Instruction* for Something New Phonograph Repro- clearly written handbook which explains in untech- Curtlfts MlUtary Tractor ducers. This Particular Type Has a Dla- nical terms the principles and practise of alternat- BIcHot Monoplane fram of Special Composition, and the ing currents for the practical electrician and stu- Nleuport Monoplana 25c Stylus Arm Is Secured Thru a Bridge dent. Taube Monoplane Arrangement, Similar to the Sounding Curliss Flylna Boat EACH of Wright BIplana Board a Guitar. It Is Said to Give Cecd Pcoll Racer Excellent Reproduction. GERMAN ENVOYS TOLD TO SUR- — Neto Aeroplane Catatog S cent* None Free RENDER, VIA RADIO. T*lla about Model Aoropianei. Badng Aeroplanes. Plying Toys, aDd parts and supplies to build them clash and approaches the living; voice, with. 48 page*. Sent only upon receipt of 10 cents. A wireless message sent to the German IDEAL AEROPLANE & SUPPLY COMPANY whether of soprano, contralto, tenor, bari- 70-82 WMt Broadway Nsw York City delegates from German headquarters tone or bass, quite as natural as life. authorized them to sign the armistice. Even the resonance of the violin and the The German commissioners remained up tone the tlute of are marvelously perfect. all night waiting for final instructions. CHEAPEST WAY TO GO It is held that band records are repro- When the radio message arrived they has- i on 9 bicycle — a dozen miles for duced with all the tone values of instru- 1 fcnt. That's why in Europe one tened to a private train in which Marshal v.cry six persons rides a bicycle. All ments, every overtone and undertone Foch was living, and which formed his armies use them by iliousands. It is the brought out harmoniously, without nerve- \vorkinan*88treetcar, with tliccost headquarters. Marshal Foch was asleep T'i the rides saved. A complete out- wrecking stridency, while orchestral com- at the time. He was aroused. He received floor f;ynina8iuin that keeps you binations are greatly improved. The re- fit in nind and muscle. formal word that the Germans had come cordings of the great symphonies are revivi- Mead's Factory to Rider to sign. fied with all the original sublimity; re- first to affix his signature to the mo- Siles Plan Saves you ?li) to ?J0 nn all The _ ' lAtc^i war approved KanRer models. animated in just the right volume for home mentous document was Dr. Mathias Erz- .'10 Dayft Fre© Trial and Frt-e Delivery. enjoyment. The violins, cellos, oboes, clari- berger, civilian head of the commission. Parts, Repairs at half usual prices. TIppe nets, bassoons, saxophones, flutes, piccolos, Illlkvijon't buy until you get our UlR The other delegates followed. Free Cataltn: describing^ all the wondcri.il new horns, the "brasses" including the great As they signed, one by one, they saluted, offers. Iibcrtl tcrini aridluwprices. Write a postal now, CYCLE tuba, the "percussion" containing drums, Marshal Foch and his aide-de-camp re- MPAn COMPANY cymbals, bells, special effects as the imita- sponding courteously. •Wlfc»'^fc^ Department c-i'^7 CHrcrrto tions of birds, church chimes, are all as real In the meantime, across the network of as the record is made. wires running from Marshal Foch's head- 15 PHONOGRAPH RECORDS $1 Any talking machine can be equipt with quarters to the various battlefields, the ^^ TITLES ALL GOOD this reproducer in a moment, without tools. order for cessation of hostilities at 11 //*• Sent PARCEL POST PREPAID any- Either steel or fiber needles will work per- o'clock, Nov. 11th, began to be flashed up ^ '^^ where in the United States. Enclose Money Ord'/r or Currency. fectly with the reproducer, whose weight and down the far-flung western front, while INDEPENDENT DRUG CO. is less than four ounces, so that records from Paris and London the news started Dept. S. Wabash 100 204 Ave.t Chlcaco wear indefinitelv if care is used. on its joyous trip around the world.

You benefit by mentionino the "Electrical Experimenter" u/hen u/riting to advertisers. :: !

January, 1919 ELECTRICAL EXPERIMENTER 653

7Big Volumes I Cents aDay Shippedi for Examination. kLJJ, FREE CTCLOPEDIA CYCLOPEDIA CYCLOPcIil" CYCLOPEDIA CYCLOPEDU CYCLOPEDIA CYCLOPEDU I.WLIED APPLIED APPLIED APPLIED APPLIED APPLIED APPLIED ELECTRICm^ .-LECTRlcm' EtECTRICm aSTRICm ELECTiUCm' iECTWCrr/ EUCTRlcm

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Partial Contents 7 Big Volumes Written by 27 Electricity: Great Vol. I. Elenu^ls of — Magnets -Electromagnets. The Electric Current: Re si stance- -Un- derwriters Requirements-- Power Stationa and Equipments — Outside Wiring--Higb Tension-Special In- Mcaaure- Authorities Yours for stallation3-£?e(r(ri>ai — 7 Cents a Day mrnts: lnstruments--M e asur i n e lusulation-- Methods: Resistance hardest way to learn Electricity is through your oim. e.r_rpertettre. The easiest way to learn is Distribution Systems — Watt- Hour THE Meters; Construction, Installation. through the experience that others have j) aid for hi time and vioney. Here in practical, easy-to- Testing. understand form, you get the benefit of what '^7 greatest electrical authorities in America and all over Dynamo Electric Mach- Vol. U. this vast fund of experience in inery: Magneto Elecuic Induction the world have learned, and you get convenient book form, so that -. Generators — Conatrue tion-- Prac- you can read and study in your own home in your spare time. tical Design. Ti/pta of Gtmeratora and Motors: Direct anJ Alternating This is the greatest opportunity of your life to become an electrical engineer, sub-station operator, dyna- Generators and Motors. MoiorGen- tender, or get one of the other big-pay jobs in the electrical field. less eratora-- Induction Motors. mo to any For than you spend for movies, train yourself to step up to the jobs Vol. m. Direct Current Motors: tobacco or you can paying S'3,500 to $5,000 a year. Efficiency-Torque—Speed-Power-- Multi-Voltage Systems. Manage- No ment of th/namoa and Motors: D. Money C. and A. C. Plants--/-ioftiinff: In- Lamps Shipped Free Examination -Tungsten on candescent Lamps- in Adveoice -Nitrogen Filled and Mercury Vap'ir Just gliirue at the partial list of contents of these 7 volumes in the panel at the left. Tliink how much there is for --Arc L.amp3-- Residence-- Photo- Iiome-study library of electricity. Then write at once for metry. you in this great tiie books themselves. Examine them in your own home for a week. Send tliem back if you are not satisfied. But if you decide to own this pay-raising- set, Vol. IV. Altematino Current Machinerv: Simple Alternator— In- send only %% and then only §^2 a month until the special half price is paid. Examine the books— see how they take struments — Polyphase Systems -- you through every detail of each special branch of electricity. See how they {.'ive you all the necessary tables and Armature Windings -Trans formers formulas in simple, untechnical form. Note the frequent test questions which enable you to examine yourself. —Rectifiers—Motor Generators. Note the 2,600 illustrati

You btndit by m*ntiouing the "EUctricot Experimenter" when writinif to advertisers. 654 ELECTRICAL EXPERrMENTER January, 1919 WINTERTIME USES FOR THE ELECTRIC FAN.

AMATEURS! Complete test books written by leading experts. (Continued from page 619) Up-to-date, describing all 19IS apparatus and practices. These books furnish all information be screwed down so as not to fall over required and Get Ready for to enter the wireless and ariation servtees. injure anyone. Written to prepare you for actire service in the shortest possible time. In use af all army and Another illustration shows a very ef- navy schools and the Opening Day camps, universities, coiieges and fective aid in the drying of milady's silk technical schools. Each book Is a practical home stockings, gloves and study course covering the entire subject and giving handkerchiefs. A information not to be found in any other sources. funnel "B" can be easily constructed out of Practical Wireless Telegraphy Vacuum Tubes ordinary cardboard to fit the protective By Elmer E. Bucher, gruard, and attached with wire. Or, it can Orrector of Initructlon Marconi Initltute in Wireless Communications be made a bit larger so as to slip a few The r«cOKUlz«d st&nd&rd wireless Uxt book By Elmer E. Buohflr inches over the protector, TT«aLs each topio i«parat«ly and completely, and perforated at two An elementary text furnishes a prosressiTe atudy from first principles book for experimenters, stu- or four places and tied at the back with to expert prtctloe. CoTera completolr the eallre dents and operators. Gives complete description field of wireless (fiudamentals. oonatructloo and and makes clea,' every fimdamental operatlnK string. Of course the width of the other principle pracdeal operation). More than 60,000 copies of of the vacuum tube. Graphic diagrams reveal end should be much narrower in order to ihla book bate already been sold. 81se 6x0 at a glance the various uses of the vacuum tube. The only text InchM. 3S3 pa«M, 310 lUustraUons. Handsomely book on the market devoted produce the conical shape, as the sketch il- solely bound In full cloth with coTer stamplns In sold to the various applications of the oscillation antJ black. Pries, 11.75 vestpald. valve. Shows over one hundred different circuits. lustrates. A small piece of cardboard Size 6x9 inches: 130 diagrams and illustrations. formed into a cylinder, and sewn or pasted Handsomely bound in cloth. Price. $1.75 postpaid. Radio Telephony together so as to exactly fit the end of the By Alfred N. Gsldtmltli, Ph.D. Practical cone, is also fastened to it with wire. This Olreetsr ef Rsdlo Laboratory, Collsgs of ths Aviation City is done by perforating of New York Incluiiing Construction and Operation both and sewing the Written In clear style to sppesl to eren the By J. Andrew White wire from one hole to the other. The betlnner. Treau all aspects of Badlo Telephony An invaluable book for intensive study men Including a description by stocking is then slipt on and can be clamped of Badio Telephony In preparing to become aviators. Gives the complete pcmcuce for a distance of more than five thousand working knowledge required for actual down, (The clamps that are used mll^. Covers the flying and on jam sublect of construction and op- air combat. The subjects covered include waUoo thoronchly operation jars to make them air-tight and will be found an InTaluable and care of aviation engines, reconnaissance, would serve .Ud to men who seek map to UnproTe their position in reading, signaling and operation with military very nicely here.) the wireless profession. Slie Also small hooks made 6x0 Inches iSS bodies, radio and Its uses, meteorology, and night Pa«es. 2a lUuslrstions. of wire Handiomely bound In flying. Size 6x9 Inches; hundreds of Illustra- (picture wire would do), invisible full cloth sumped In gold. Price, $2.00 postpaid tions. Bound In full cloth. Price $1.75 postpaid. hairpins, etc., can be affixt to the end of Th«je Text Booki Hare Been Used in Training Over 60,000 Men During the Past Year the funnel, on which handkerchiefs, stock- THE WIRELESS AGE ings and gloves can be fastened. In the latter case it is not necessary to make the •Ji5fi^°'L^."^'*° .""••f^'"" devoted exclusively to the wireless art. Records all developments hi the j""" coinmerdal iSSP^,L^. .'^ii' fields. A magazine that keeps you posted on ail the latest doings small cardboard attachment. It is readily broader working knowledge of the art of wireless iSILS V 1^ „ than possible through any other feature articles with vivid illustrations and practical JS^li>rtert AjlniS;^' t.*"''„''^1™' suggestioni tor irS,.iSJ?^ ."'""v ,Pf«^"caI training courses by experts on wireless telegrsphy, aviation. mUltary !«Sfr^''„™',ii,*. .'I""- 9^ "> "" "eWMt news-stand and secure your copy, or, we will mall pceipald upon receipt of price. 20c per copy, $2.00 per year. ^•'^ Wireless Age for one ye.Tr and your choice of Practical Wlre- vPrff AI ACCrD Telegraphy, UlLtililL UrrLA L"" Vacuum Tubes or Practical Aviation for $2.75 or. Radio Telephony for $3.00. Save money and subscribe now. 33 ELM STREET THE WIRELESS PRESS, Inc. NEW YORK CITY Attractive circular fully deacribing our complet* lino of books, *'aent free upon request. Ask for Circular E.

Thm HouM of Taylor HOTEL MARTINIQUE BROADWAY, S3D STREET, NEW YORK One Block from Pennsylvania Station. Equally Convenient for Amusements, Shopping or Business 157 PlMuant Rooms, with Private Bath, $2.50 PER DAY. To Improve the Cold Air Box Draft To Your '"sta" nrI?»"D: An Electric Fan In the' 257 Excellent Rooms, with Private Bath, X wl^ li'.f^fl^ After the Manner Illustrated. A North" and "South" Cold facing stra«t, southern ezposnre, With Air Box. Fitted Suitable Cut-Off Dampers, Makes a $3.00 PER DAY. Very Dependable Furnace, No Matter Which Alse Attractive Rooms from $1J0. Way the Wind Blows. Hie Rsstaaruit Prices Are Moat Moderate.

understood that the forced air thru this " funnel dries the articles in no time. Should THERE'S MONEYIN IT" It be inconvenient for you to make this funnel, the handkerchiefs, stockings, et cetera, LEARN TELEGRAPHYfsSSI can be attached to the protector itself by pins or hairpins. With this IMORSE ANDWIRELESS-n^--— method it will take slightly longer for them to dry. Care should be taken to attach the articles before you set the fan going. Take them TEACH off after you have cut VOURSEUH off the current with the snap switch and the fan has fully In half the usual time, at trifling cost, with the stopt. wonderful Automatic Transmitter. THE OMNIfiRAPH. This brecaution should be taken whenever Sends unlimited Morse or Continental messageo, at the electric fan is handled in any way. any speed, just aa an expert operator would. Figure "B" shows a handy device that can quickly be affixt Adeglsd by U. S. Gov't. 4 itylet. Catalotu* Ira*. to or taken off the guard. A circle of tin is cut in the manner OMNICRAPH MFG. CO. illustrated, allowance being made for small projections which 38L Cortlandt St. New York are bent over and formed into hooks. It can be affixt to the protector guard with the projecting tabs. If the tin is not handy, cardboard will do just as well, except that the hooks must be made of wire .V'.; Monuments — Mausoleums— Statuary or old hairpins. A good way to make these No matter wkat joar needa, we eaa aerve yen moat advan- hooks is to thrust the hairpin thru the per- tateoualr- Eatimatee and daalfa* aakmltted. Mall orders ao foration, the two ends first, twisting tnem sarefnllr eaecatad aa tiioofk 70a had called la peraoa. Write around at for particulara. the other side of the perforation and then spreading them apart. About four J. L. Wegenaar Co., 299A B'way.N. Y. cardboard tubes are inserted and sewn with SPECIA1J5TS IN DESIGN AND CONSTRUCTION wire as aforementioned to a piece of cardboard larpe enough to fit the wire cage pro-

Vou benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January. 1919 ELECTRICAL EXPERIMENTER 655

tector or guard, to which it is in turn fastened. The use of hooks or rubber bands is also made here in securing the articles to the tubes. How it Feels to Earn Another use to which the electric fan can be put is the drying of photo negatives. The draft of air from the fan causes the water on the negative to evaporate, so that $1000 a the Week they will dry much sooner than under ordinary process, which is to spread them on racks and allow them to dry by them- By a Young Man Who Four Years Ago Dreiv a $25 a Week Salary. Tells selves. It proves of great help to the ama- Hozv He Accomplished It. teur as well as the commercial photographer, who particularly should make use ' earn $1000 a week? How of this method when business is rushed, How uuea It feel to year I made $30,000. My second year paid me dn*-s '* feel to have earned $200,000 in four years? $50,000. My third year netted me $70,000. Last or certain pictures are in special demand I i.ow does it feel to be free from money worries? year, due to increased costs of materials, my profits Nothing, perhaps, is more exasperati;'^' does it feel to have everything one can want? were only $50,000, though my of business \ How volume than to enter a public telephone booth and These are questions I shall answer for the benefit increased. New plans which I am forcing through, of my reader out of my own personal experience. will bring my profits for the present fiscal year having to breathe the suffocating air, which And I shall try to explain, simply and clearly the up to $65,000. is many times laden with the odor of stale secret of what my iriends caJl my phenomenal Earning a thousand dollars a week makes me tobacco. The electric fan might well be success. feel secure against want. It gives me the money Let me begin four years ago. At that time my with which to buy whatever will make my family employed in all such in'-tances. wife and I and our two babies were living on my happy. It enables me to take a chance on an in- Have you ever tried to look thru the win- earnings of twenty-five dollars a week. We occu- vestment that looks good, without worrying about dow of a bakery or lunch room covered pied a tiny fiat, wore the simplest clothes, bad to losing the money. It frees my mind of financial be satisfied with the cheapest entertainment—and worries. It has made me healthier, more contended, with frost, and dimly make out a few of dreamed sweet dreams of the time when I should and keener minded. It is the greatest recipe I know the many delicacies therein? After the be earning fifty dollars a week. That was the limit for happiness. it to be the limit Prof. windows have been cleaned till they shine of my ambition. Indeed, seemed Haddock's lessons, rules and exercises in of ray possibilities. For I was but an average man, will training have recently been compiled and pub- like mirrors, and a great deal of effort without influential friends, without a liberal edu- lished in book form by the Pelton Publishing Co., been expended to make the articles for sale cation, without a dominating personality, and with- of Meriden, Conn. I am authorized to say that any most appealing, along comes Jack Frost out money. reader who cares to examine the book may do so .With nothing to begin with, I have become the without sending any money in advance. In other and spoils it all. Some store-keepers have sole owner of a business which has paid me over words, if after Rve days' reading, you do not feel tried filling the window with warm air, but $200,000 in clear profits during the past four years that the book is worth $3, the sum asked, return it this is rather bothersome and expensive, as and which now pays me more than a thousand dol- and you will owe nothing. When you receive your lars a week. I did not gamble. I did not make ray copy for examination I suggest that you first read the cold window-pane cools it and a fresh money in Wall Street." My business is not a war the articles on the law of great thinking; how to de- supply of warm air must be employed. The baby—on the contrary, many others in my line velop analytical power; how to perfectly concentrate most effective, least troublesome, and in the have failed since the war began. on any subject; how to guard against errors in In four years, the entire scheme of my life has thought; how to drive from the mind unwelcome end the cheapest way, is the electric fan. — changed. Instead of living in a two by four fiat, thoughts; how to develop fearlessness; how to use It circulates the air evenly, thus keeping a we occupy our own home, built for us at a coat oi the mind in sickness; how to acquire a dominating fixt temperature, with the result that no over $60,000. We have three automobiles. Our personality. children go to private schools. We have every- Never before have business men frost will form on the window. and women thing we want, and we want the best of everything. needed this help so badly as in these trying times. One of the accompanying illustrations Instead of dreaming of fifty dollars a week I am Hundreds of real and imaginary obstacles confront shows a very good use for an electric fan dreaming in terms of a million dollars—with greater us every day, and only those who are masters of possibilities of my dream coming true than my for- themselves and who hold their heads in the wintertime to help out the cold air up, will suc- mer dream of earning fifty dollars a week. ceed. "Power of Will" as never before, is an abso- circulating system to hot-air and other fur- What brought about this remarkable change? lute necessity—an investment in self-culture which ances. This suggestion was made by one of What transformed me, almost overnight, from a no one can afford to deny himself. slow-going, easily-satisfied, average man into a Some few doubters the Westinghouse engineers, and the sketch — will scoff at the idea of will positive, quick-acting, determined individual who power being the fountainhead of wealth, position shows clearly how the fan is placed directly admits no defeat, who overcomes every obstacle and and everything we are striving for. But the great in the cold air duct. The fan may be placed who completely dominates every situation? It all mass of intelligent men and women will at least began with a question my wife asked me one investigate for themselves by sending for the anywhere in the duct, its function being to book evening after reading an article in a magazine about at the publisher's risk. I am sure that any book create a very strong draft or suction so as a great engineer who was said to earn a $50,000 that has done for me—and for thousands of others to act firstly as a forced draft for the fur- salary. —what "Power of Will" has done—is well worth "How do you suppose it feels to earn $1000 a investigating. It is interesting nace, and also to draw in a sufficient quan- to note that among week ?" she asked. And without thinking, I re- the 250,000 owners of "Power of Will" are such tity of fresh air at all times thru the inlet plied "I haven't the slightest idea, my dear, so prominent men as Supreme Court Justice Parker; in the cellar wall. Especially is this sug- the only way to find out is to earn it." We both Wu Ting Fang, Ex-U. S. Chinese Ambassador; laughed, and soon the question was apparently Lieut.-Gov. McKelvie, of Nebraska; gestion of value when the wind or air cur- Assistant Post- forgotten. master General Britt; General Manager Christeson, rents blow from the opposite side of the But that night, and for weeks afterward, the same of Wells-Fargo Express Co.: E. St. Elmo Lewis; house in which the cold air intake is situ- question and my reply kept popping into my brain. Governor Arthur Capper of Kansas, and thousands I beg;an to analyze the qualities of the successful of others. In fact, today ated. In wiring up and installing such a "Power of Will" is just men in our town. What is it that enables them to aa important and as necessary to a man's or wo- fan arrangement, it is best to connect a get everything they want? They are not better ed- man's equipment for success, as a dictionary. To small 4 c.p. pilot lamp on the motor side of ucated than I—indeed, some are far lets intelligent. try to succeed without "Power of Will" is like But they must have possessed some quality that I trying to do business the switch as a reminder to the furnace without a telephone. lacked. Perhaps it was their mental attitude; per- As your first step in will training, I suggest im- tender that the fan is operating, for it is not haps they look at things from an entirely different mediate action in this matter before you. It is not necessary to keep it going except at certain angle than I. Whatever it was, that ''something" even necessary to write a letter. Use the form was the secret of their success. It was the one thing below, if you prefer, addressing it intervals, as for instance when a house is to the Pelton that placed them head and shoulders above me in Publishing Company, Wilcox Block, Meriden, very cold or when the wind is blowing on money-earning ability. In all other ways we were Conn., and the book will come by return mail. This the opposite side of the house. the same. one act may mean the turning point of your life, Determined to find out what that vital spark of 3S it has meant to me and to so A very good idea in this direction is to many others. success was, I bought books on every subicct that The cost of paper, printing and binding has al- provide two-way cold air ; inlet a box one pertained to the mind. I followed one iaea after most doubled during the past three years, in spite * being located in the north wall and the another. But I didn't seem to get anywhere. Finally, of which "Power of Will'' has not been increased when almost discouraged, I came across a copy of in price. The other in the soutli wall of the house. Suit- publisher feels that so great a work "Power of Will." Like a bolt out of a clear sky there should be kept as low-priced as able dampers should possible, but in be used of course to flashed in my brain the secret I had been seeking. view of the enormous increase in the cost of every cut off one or the other as the case may There was the real, fundamental principle of all manufacturing item, the present edition will be the success Power of Will. There was the Drain fac- last sold at the be, so that when the wind blows from the — present price. The next edition will ulty I lacked, and which every successful man cost more. I urge you to send in the coupon now. north, as the arrows show, then cold air possesses. "Power of Will" written Prof. can be taken from this inlet ; while when was by Frank Channing Haddock, a scientist, whose name ranks the wind blows from the south, the cold air r: with such leaders of thought as James, Bergson and PELTON PUBLISHING COMPANY intake from that direction can be utilized by Royce. After twenty years of research and study, closing the north damper and opening the he had completed the most thorough and construc- ' 30-A Wilcox Block, Meriden, Conn. south damper. Great care must be taken tive study of will power ever made. I was aston- ished to read his statement that, "The will is just I will in every instance to keep the cold air duct as susceptible of development as the muscles of the examine a copy of "Power of Will" at your risk. I agree thoroly air-tight thruout its entire length, body I" And Dr. Hadclock had actually set down I to remit $3 or remail the Book the very rules, lessons and exercises by which any- in 5 days. and it is often best to have a plumber or one could develop the will, making it a bigger, furnace man install the fan if you are not stronger force each day, simply through an easy, familiar with the progressive course of training. work, as you may easily I Name It is almost leave openings in the duct, thus creating a needless to say that I at once began to practice the exercises formulated by Dr. Had- false draft and losing as much or more dock. I need not I And recount the extraordinary Address. than what you at first set out to gain. Hot- results that I obtained almost from the first day. Shortly after that, I -took hold of business air furnaces are widely used, but in some a that for twelve years had been losing money. I started cases do not operate satisfactorily for sev- with $300 of borrowed capital. During my first I City State.

You benefit by mentioning ike "Electrical Experimenter" when writing to advertiiert. 656 ELECTRICAL EXPERIMENTER January. 1919

eral reasons. Among these are insufficient

area of the cold air duct ; furnace not lo-

cated low enough in cellar bottom ; or else hot air pipes rise at too low an angle. These should rise at a sharp angle, preferably not less than 45 degrees at the top of the furnace, and will always work better when kept close to this angle or approaching the vertical, than they will in the horizontal direction. In the majority of cases it is usually found that the wind blows from the north or some northerly direction more than any other. Therefore, where but one fan is available for this use, it should be installed in the north cold air box. A large and airy but unfinished attic room in a building occupied by a school was suddenly needed in order to accommo- date an extra class. It took only a few days to wire and plaster it but the time required for natural drjdng could not be spared and use of the common salamanders was inadvisable because of fire hazard. Three 16-inch electric fans were placed on boxes and turned so as to keep a continual circulation of air thruout the room. With windows poen and the fans runnine for a THE ELLIS "MUSIC MASTER" REPRODUCER day and night, the fresh plaster dried quick- Is the Ideal Christmas gift for anj-one who owns a phoaograpb or talking machine using ly so that carpenters and decorators could disc records. This wonderful little reproducer bears the same relation to m the reproduction finish the room shortly. uf records as does Stradlvarlus to the making of vlolina. Both are masters. i There Is as much difference In the effect of the Ellis Reproducer and ordinary reproducers, as there Is between a genuine Stradlvarlus and a cheap factory made vloUn. 2 MEN MILE APART BURNED BY As one user said: "Mr. Ellis, your reproducer Is soulful and Inspiring. The overtones are remarkable and wonderful, and the tone shading very beautiful." SAME ELECTRIC FLASH, OrdlDUT reproduoon. tucb u ara supplied with all pboDoin'apbs or talking machines, give a hanb, rmipinx. aonoTlng found and reproduce the human volc« with a disa^rreeable nasal twang. Recently two men, R. C Deyo and Henry The EUla flllislo Uast^r miês ererr note and tonf as clear aa a bell— and reproduces It Id Its true Nisson, both in the employ of the San tone coloring. It Ls a marralous little Instromeot that wlU please anyone who appreciates and can L-^jniprehend the difference between good and Indifferent rendition of music. It la truly a "Music Joaquin (Cat.) Light and Power Company, Mastpr." were the of The nila "Mtuio Ma«t«r" Is made for all machines using disc records. It la Ugbter than working on top telephone poles ordinary reproduoera, therefore preserrea and prolongs the life of records. The ooat Is little, but for the company, 50 miles apart, when an the aatiafaoUoo greau unaccountable and unknown current of 10,- Write today for circular E, which gives full details. 000 volts went flashing over the wires and J. H. ELLIS, P. O. Box 882, Milwaukee, Wis. gave each man such a shock that it is a * miracle that they escaped instant death. Both men were similarly burned about the hands, both were rendered unconscious, and only restored to consciousness by extraordinary efforts. The men are now recover- ing from burned hands and the electric shock at the San Joaquin hospital. Wireless Stations Will Shortly Re -open Deyo was at work on the top of a tele- Date, only, uncertain phone pole about twenty miles west of Bakersfield, Cal. He was busy on what the Heed Our Advice ORDER NOW electricians call the 60-phone line, when a shock came to him. fell to the A3 a matter of law Congress loses all control over wireless receiving stations He ground, and transmitting stations with a range within the borders of the state where a distance of 25 feet. located as soon as peace Is declared. The Radio Inspector of this district has When, after an hour, Deyo came to his already asked our co-operation In printing in the next edition of our catalog the senses, he was put in an automobile necessity of securing licenses for transmitting sets with a range beyond the and borders of the state. No vrireless manufacturer wants the stations to open to- hurried to the San Joaquin hospital in this morrow. They could not take care of the business. Order prepared. now and be city. Dr. N. J. Brown was called for at- We have a big stock of wireless Instruments. tendance. Both of Deyo's hands are burned No. 11 is our latest catalog. No new price list. to a crisp at the palms, and he is suffering Please do not write for catalog If you have No. 11. Paper costs three times as much as formerly. from hurts he received in his fall from Let the amateur without a catalog secure one. Writ© for prices In advance. Just now we have no the top of the telephone pole. price list, because the changes have been frequent. Will so advise through this magazine when re- At the same moment Henry Nisson, aged vised price list is ready, which will be as quickly as possible. 28 years, was engaged in exactly the same '^''^ ^^ stamps todaj for our big 300 page No. Electrical ^cAi«aSpnH *jvfir ^ 11 and Wirelesi Catalog. Any wireless amateur will tell you It Is the one cataloR to have. Tou need no others. Our catalog sort of work for the San Joaquin Light eontalna moat everything in wireless worth while, and U a guarantee that the goods are dependable. and Power Company at Pond. He, also, was at the top of a telephone pole, and he THE WILLIAM B. DUCK CO., 230-232 Superior St., Toledo, Ohio was served the same as Mr. Deyo. He fell unconscious, and his companion rushed to Dr. Copeland's office for help. His hurts are the same as Mr. Deyo's, only he has not the bruises by the fall. He Learned VAUGHN M. AMES, the roung mui In the picture, dtd It. Bo htve lefflona of others. Wb ouarantM you can l««rii the GAS VERSUS ELECTRIC RANGE. entire A lyttem In five evening! ; then ao- Kl- Shorthand QUlre apeed. Become proficient In a tenth of tht The gas range is little better than half as time It would take you with any of the old, eom> plex tyltemi. K. 1. Shorthand la the new efficient as the electric range. Recent tests in evenings simplified iitf£o?Taph; that experts coniider the show that the top surface of the electric 5 molt conclie legible and meet ihorthand In the wnrld. Learn by mall. range requires but 64 per cent of the en- Uliy BO throtigh montha of drudaery and spend ergy necessary to do the same work the can! ten times aa much money learning aome trouble- on -You ftfime syatemT K. I. atndents are fotlnd In every top surface of the gas range. The elec- weUi of life—among doctors, lawyers, teachers. elwtrlclanfl. enrlneera. and huslDeaa-men, aa well as steaiographera and aecretarlea. Used In army and navy, tric range oven requires but 23 per cent of [11. 'I S'-krowl-Mlirpd tjy progreaalve commercial schools aa tke moat practleal of ahonhand 9yat«ma. the energy necessary for the same work in j\j"lO KâyaDavft .n|j|jruvaiAnnrnvfll ^- ^- Shorthand will be a big help to you In any vocation. You can afford to |,„, |, |„o,u„ |, |, ,„ ,,,, ,nj ^„^ ,„ nî, Daa't think K. I. Shorthand a gas range oven. The electric range oven 19 meant only for fteaosraphera. Learn thla Invaluable ayatem so you can be more than a stenographer. It conaervflS your time, doea your rememtiertnt for yolL Hence promotes your efficiency and puts you In line for is much more efficient in proportion than more rapid advancement. Valuable In ycnir electrical or mechanical enterprises. the top surface as compared with the oven We teach yu the entire courts on approval for 30 days with the underatandlng that you need not pay on* cant If you do not learn. Prove it for yotllself by receiving two flrat lefcfons FBEE. and top surface of the gas range. Under ' "" "* come*" <"" system with olTeni of text books on stenography, IVlOreMnrA ThAflnan a T«»»fI exi OOOKRnnic . actual household conditions the electric 1 we give you personal mall tuition. Experts guide you In aMulrlM Pfoflelaney and accuracy In the shortest time. Free Lessons, testimonials and complete Information sent on request range requires about 55 per cent of the en- station F, (EH-SOO), New York, N. Y. or ergy used by the gas range to do the same rVIl'N^JKINC. TNSTTTIITFI1>IJI1IU1IL, inC«2S.Inr Wabash Av.. (lfH-300). Chicago, 111, work.

You beneHl by mentioning the "Electrical Experimenter" when writing to advertisers. 657 January. 1919 ELECTRICAL EXPERIMENTER

NIKOLA TESLA AND HIS machine. The rural telephone is invading many miles INVENTIONS. country districts at the rate of per day, and all farm machinery is being tractors, which now (Continued from page 615) operated by the aid of haul the wagon and work the hay loader in either a dreamer or, worse yet, crazy. the hay field. Next year, it is said, reapers The fact is the world does not understand and mowers in great numbers will be drawn you because you live in the next century. by tractors. Moses was a great man, but the Bible teaches us that he was "heavy of tongue" DEVICE FOR PROTECTING ELEC- and could not make himself understood. TRIC MOTORS. His brother therefore always spoke in his stead, announcing to his hearers what Moses A motor protection system which, it is had to say. Why not let the Experimenter claimed, does away with the trouble and ex- be your brother? Why not let us translate pense of cleaning motors, has been devised your work into a language that the man and marketed. The usual type of installa- in the street can readily understand? We tion, it is pointed out, in working out this have the knowledge and the technical train- system consists of casings which enclose ing to do your inventions justice by means each end of the motor and make it dust of graphic illustrations and wash drawings. proof. A fan is attached to the end of the The public does not want patent drawings motor shaft, a dust separator, and an air or patent language. It wants pictures and intake pipe running to a clean air supply inventor, plain English. You are a great out of doors. When the motor is started, but your 21st Century training prevents the fan draws in the cool, fresh air thru yourself understood to a you from making the dust separator and forces it against the 20th Century public. My plan is to run one rear end of the motor, thru the windings of your inventions every month, in plain and out thru the laminations. Part of the fully illustrated. That means that English air is forced thru a by-pass to the front deal it will probably take over two years to hood so that the same action takes place important inventions. with all of your more on both sides of the motor. At the end of this period the articles can As a result, it is pointed out that the be published in book form, a thing that motor is kept clean and has a large volume does not exist at present. The plan is two- "I Can Succeed!" of cool, clean air constantly passing thru it fold. First, the world at large will at last which carries away the heat as fast as gen- "What other men have done with the understand the highly important work you erated. Motor casings are provided with help of the International Correspondence have accomplished and will fully recognize Schools, I can do. If the I. C. S. have you. Second, it will be of greatest benefit raised the salaries of other men, they can to Science, to whom your inventions will mine. If they have helped others then not be the sealed book they are today." raise can help me. To me, to advance, they " Knowing that Tesla had in the past con- I. C. S. means 'I CAN SUCCEED." tinuously refused similar offers of dozens Make up your mind right now that not this country as well of great publishers of another day shall pass until you have I was not at all sanguine of my as abroad, made your start toward success. own plan. Great was my surprise there- For27years men in of flees, stores, shops, fore, that he not only gave his consent, but mines, railroads, and in the he actually agreed to prepare each article factories, Navy have been winning pro- personally with the Editors' collaboration. Army and motion and increased salaries through and Dr. Tesla wants it expressly understood the I. C. S. More than 100,000 men that he is undertaking this great work women are getting ready right now with generation. chiefly to educate the young I. C. S. helpTor the bigger jobs ahead. could not possibly reach He felt that he No matter where you live, the I. C. S. will come to such a large electrically trained young man- you No matter what your handicaps, or how small your circum- hood, save thru the medium of the Elec- Forced Air Cooling Apparatus Shown In- your means, we have a plan to meet Motor. stances. No matter what career you may choose, trical Experimenter. With its circulation stalled on a surely suit some one of the 280 I. C. S. Courses will above 100,000. all enthusiastic experiment- your needs. doors permit of ready inspection ers, Tesla feels that his greatest mission in large to a When everything has been made easy for you— resistance, air-gap, bearings, spent with the I. C. S. in the life, namely, to assist our rising generation, of brushes, when one hour a day will bring you a bigger and the like. The dust separator is also quiet of your own home will come near fulfillment. more comforts, more pleasures, all that that the screens can income, provided with doors so success means—can you let another single price- Tesla's articles will therefore Nikola be readily removed. The equipment can be less hour of spare time go to waste? Make your cost, run serially every month in the ELEC- applied to motors without moving them and start right now! This is all we ask: Without without obligating yourself in any way. put it up TRICAL EXPERIMENTER. The ar- requires short time to install. Besides re- a to us to prove how we can help you. Just mark ticles will Inventions" be entitled: "My ducing the temperature and increasing the and mail this coupon. —by Nikola Tesla. Every article will be efficiency, the maker points out that the entirely original; each will be illustrated protection provided allows the carrying of INTERNATIONAL CORRESPONDENCE SCHOOLS with our own new illustrations and with overload without shortening the life a large BOX 6170, SCRANTON, PA. such wash drawings as made this jour- eliminates fire hazards. of the motor and Esplaln, without obli^tin? me, how I can qualify for tho nal successful. first article will so The posiUoD, or In the subject, before^ which I mark X. appear in our February number. ^EIECTUICIL ENUINFKIl DSALESMANSHI? Klectrlo Mehtlnff and Itjfl, D ADVERTISING Electric Wiring D Window Trimmer We wish to congratulate E,\perimenter DANIELS TELLS OF FOE RADIOS Telesraph Engineer Show Card Writer readers for having obtained for them prob- ^j Telephone Work Sign Painter SCOUTS FOUND. JUErnAMCAL F.MJINEEU C Railroad Trainman ably the greatest technical news feature of ^ BlechanlcQl Dmrtsman iilLLUSTRATING A telegram from Secretary of the Navy BHa<.liln» Shop I'ractlc* ^Cartooning a generation. I caution you: Expect much! Toolmaker DBOOKKEEPER Daniels received by the Boy Scouts of Gas Eniiine Operotlns ^Stenotraplier and Trpbt America characterized them as "chivalrous CIVIL ENGINEER TlCert. Pub. Accountant Siirrerlntr and Mapptnip DTRAI FIC MANAGEP. * young crusaders" because of their work MINE FOIt^HANo^F^U•tt 3 Railway Accountant 9TAT10NAI1T ENGlNIiEll U Commercial Law during the war. It also FARMERS AND ELECTRICITY. disclosed that the Marine Engineer IgOOD ENGLISH Scouts, working on behalf of the Govern- Ship Draflsman _ Teacher ARCHITECT ^Comnon School Sobleota Within the past three years the farmers ment, had discovered hundreds of illegal Contractor and itnllder HMathemulica wireless plants. irehltectui-al Draftaman CIVIL SERVICE of the United States have purchased one Concrete Builder D Railway Mall Clerk million automobiles Twenty-six of these plants were found Structural Engineer DAlfOSIOIIlI.B 0PEOATl!«a and 100,000 tractors PI.runlNU AND HEATING DADto Hepalrlng in one day. alien, operating an and innumerable pumping engines, and A German Sheet Metal Worker DNavlgatlon inspaab!) underground radio station with a small ,, Textile 0»erieer or Supt. UAOKieOrTruKinFranch other devices run by electricity, according JCIIEMIST U I'onltry llablne IDltalto New England river supplying the motive to widely publisht estimates. Farmers ev- power, was taken into custody and interned. erywhere are rapidly advancing in the Uamc This plant was said to have been exchang- Present same direction, progress in labor-saving ing German Government messages between Occupation. contrivances being phenomenal in this coun- Street America and Berlin. Details of these scout and No try. A motor does the churning; a motor activities are expected to be made public runs the sewing machine and the washing later. City-

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658 ELECTRICAL EXPERIMENTER January, 1919

THE SET UNCLE SAM USES THE EFFECT OF STATICS ON WIRELESS TRANSMISSION.

{Continued from page 627)

energy received, even if it could be collected in its totality, is infinitesimal and would not actuate the most sensitive instrument known were it magnified many million times. The fact is these waves have no perceptible influence on a receiver if situated at a much smaller distance. It should be remembered, moreover, that since the first "Uncle Sam" needs thousands of operators aud Is calling for more all the time. Here !s your attempts the wave lengths have been in- chance to become an expert telegrapher at a small cost. The practice outfit shown here Is exactly creased until those the 8&me as used by the United States Signal Corps and comprises the fotlovrlng advocated by me were A hlfhlj pollsbed mabogany flnlabed wood base, a real high frequency buzzer giving a high adopted, in which this form of radiation note, with nickel-plated case, regulation nlckel-plat«d steel terer key. Also brasa etched plate show- has been reduced to one-billionth. ing the three International codas mounted on the base for quick practice. A new feature not found When a circuit, connected to ground and on any other set. You simply cannot mislay this code. This outfit quickly gives you speed, and enables you to learn telegraphy, Morse or wireless code to an elevated capacity oscillates, two eflfects In a short time. Special attention Is called to the buzzer which gives a clear high note, not a separate and distinct are produced ; Hertz rattling noise as many Inferior outfits now on the market. IMMEDIATE DEUVERY. We ahlp the waves are radiated in a direction at right same day that order Is received- Your money refunded If you are not Katlsfled. angles to the axis of symmetry the Priot M llluitratsd. A #% O /\ Ineludt fufflcltnt pottage of con- mallino Send Tor Shipping weight 2 lbs. ^/ ^11 ^^^ ductor, and simullaneotisly a current ii Siie ovtr all 6''x2"x7V4''. W^0\J\J fr«« Illustrated fold«r. passed through the earth. The former 150 CHAMBERS ST., THE TEWNO CO. NEW YORK propagates with the speed of light, the latter with a velocity proportionate to the cosecant of an angle which from the origin to the opposite point of the globe varies from zero to 180°. Expressed in words, VLi)t preafeersi at the start the speed is infinite and dimin- ishes, first rapidly and then slowly until a quadrant is traversed when the current pro- Atlantic City's Newest ceeds with the speed of light. From thai region on the velocity gradually increases, Fire-Proof Hotel becoming infinite at the opposite point of the globe. In a patent granted to me in Ocean Front. Unusually attractive April, 1905, I have summed up this law of during the Autumn and Winter sea- propagation in the statement that the pro- BODS. jections of all half waves on the axis of symmetry of movement are equal, which American and European Plans means that the successive half waves, the of different length, cover exactly the same area. In the near future LuxurlouB lobbies, spacious verandas and sun parlors overlooking the ocean. many wonderful results will be obtained by taking advantage Charming afternoon musicales and evening concerts. A palatial residence of this fact. for those seeking rest and recreation. Sea water baths. Fireproof garage. Illustrated booklet sent on request. There is a vast difference between these two forms of wive movement in their bearing on the transmission. The Hertz waves represent energy which is radiated and un- recoverable. The current energy, on the lights will shine and sparkle with de- MAGNETIC YOUR other hand, is preserved and can be re- light, your horn will squawk raucously and RECnnER covered theoretically, at least, in its entirety. PftUnud your engine will turnover enthusiastically if If the experts will free themselves from the AprU 18. 1(11 you play godfather to your starting and light- illusions under which they are laboring, ing battery by giving it an they will find that to overcome static dis- turbances all that is needed is a properly F-F BATTERY BOOSTER constructed transmitter and receiver with- A few minutei of your time once a month or so will out any additional devices or preventives. rejuvenate your battery and prolong indefinitely its I have, however, devised several forms of working life. apparatus eliminating statics even in the present defective wireless installations in Write today for bulletin No. 12 and obtain a prescrip- tion for this battery panacea. which they are magnified many times. Such a form of instrument which I have The France Manufacturing Company used successfully is shown in the annexed 10325 Berea Road, Cleveland, O. photograph. These phenomena have been studied by me for a number of years and I have found that there are nine or ten different causes tending to intensify them, Super-Sensitive Microphone Only $7.50 and in due course. I shall give a full description of the various improvements 1 Tbis InBtmmcnt la offered at ux extremelj low Electrical ^..c& It la QXceUeot for balldlna roar own radio have made, in the Experi- amplifier. Can alio t>« used In manj tiperlmBnt< menter. For the present 1 would only point ihere a ienaltlve microphone ! reouLred. out that in order to perfectly eliminate the DETECTAGRAPH $15 static interference, it is indispensable to redesign the whole wireless apparatus as Ttaa detecting Inatrument of murelvQa a«n>lUnty now employed. The sooner this is under- can be uaed lor detecting secret conTenatlona. Oui- flt conslsu of SenaiUve Tranraltter. 25 fL Black stood the better it will be for the further Cord. BeeelTer. neadband. C4ae And Batterr- evolution of the Art. Send for One Today and Conoince Yourse! GASTON BOISSONNAULT 26 Cortlandt Street New York A means of making use of the electric DETECTAGRAPH $15 Mik>n of SuDW-S«>iltlv« Mltrodlont Ap»«ratui magnet under water has been devised in Japan, and it promises to be of great assis- AFNESS IS MISERY tance in locating sunken vessels, to recover A WIRELESS OUTFIT FOR 20c 1 know because 1 was Deaf ftad bad Head which salvage operations on a big scale are Noisea for over 30 years. My icTiiibU We at la^i hare a low-priced wlrcleta tel'-graph ira- Anti-septic Lar Drumt restored my bear- expected after the war. tem. Wiih Oils outfit 70X1 can recelre &nd send mee- stopped Noises, willdo age* to your frlmda and sweetheart* or neighbors ing and Head and acrou the ball, etc. Tbls ot^tflt corulsta of two me- it for you. rhcy arc Tiny Megaphonel. chanical anapper tounders, one for each ttatloa; alao Cannot be teea wheo worn. Easy to put two codes of Morse Alphabet, which, with practice, will in. easy to takeout. Arc **Ud seen Com* With the aid of special oxygen masks air- oiable you to operate any telecraph system. Complete, forts. "IncipcnsiTC. Writefor Booklet and air will postpaid, for 20c In coin. plane experts believe that fighters my nromttAtemeDt olbow 1 racoTOrafl THE A. B. CO. (305 PMfIa St CHICAQO nykaailiu. A. O. UCONABD be able to carry on battles five miles above Suite 369 70 5th Ave., N. Y. City the earth. ,

January, 1919 ELECTRICAL EXPERIMENTER 659 NEW BATTERY CHARGER SIM- PLICITY ITSELF. For the Garage Man going into Battery or Service work on an ample scale, or for the Garage that has outgrown its present WANTED! equipment, an Ohio concern has brought out OFFICE HEN Auditors, Accountants, Office Man- Job ' Which 32 battery capacity Charging Outfit a new a^ers. Credit Men, Cashiers. Bookkeep- ' shown herewith. ers and Cost Clerks — $1.2U0 to $7,500. With this outfit batteries in all stages of FACTODT MEN charge can be handled by the four charging Electrical and MechanicalEngineers, Fac- tory Managers, Superintendents, Foremen, lines provided, caring for eight batteries Designers. Draftsmen— $1,500 to $12,000. Can in each line. Batteries requiring different CONSTRUCTION MEN charging rates can be handled according to Civil and Structuial Engineers. Transit- their individual needs, due to the ample men, Construction Superintendents and Foremen, Estimators, Designers and output of the machine. Different voltage Draftsmen — $1,200 to $10,000. can also charged in the same batteries be TRADES — Machinists and Tool- line, due to the automatic voltage control makers, Auto Repairers. Electri- cians, Stationary Engineers, of the Generator. Firemen. Plumbers, Car- With this outfit, battery charging work is penters, etc.—$1,200 to $2,000. claimed to be very profitable, and the makers state they have designed the outfit Fill wholly with the idea of bringing the Garage All the largest profits possible from this class of work. these positions Which one of them could were advertised yoti fill? If you haven't the in a siniile issue knowledge necessary to of a Chicago break into the big-pay class, decide to get that knoivledge These newspaper NOW! Any of the books books listed below will quickly fit writ- were you for a well-paid job— at home ten by ex- —in your spare time. perts in plain, everyday language. They are Carpentry and Fire Prevention Contracting and Insurance free from puzzling technical Five volumes, 213S pages and Four volumes, 1500 pages and more than 400 illustrations. 600 illustrations, diagrams, terms. Numerous 'illustra- Prepares for Contractor. Build- forms, etc. PreparesforCount- ing Superintendent and Car- erman. Rate Clerk, Inspector tions, diagrams and tables penter Foreman. Regular or Agent. Regular price, make difficult price,$25.00. Special price. S17.80. $20.00. Special price, $15.80. points as simple Civil Engineering Electrical Engineering Nine volumes, 3900 panes and Seven volumes 3000 pages and asA-B-C. They 3000 illustrations, plates and 2600 illustrations, plates and di.igrams. Prepares for Civil or diagrams. Prepares for Elec- are handsome Structural Engineer, Transit- trical Engineer, Power Plant man, Estimator, Designer or Superintendent, Substation Op- Compact Battery Charging Outtlt of capacity ly bound in Chief Draftsman. Regular erator or Electrician. Regular Ample for Average Public Garage and Ser- half or full price,S45.00. Special price, $29. 80. price,$35.00. Special price, $19.80. vIce.Statlon. leather (ex- Telephony and Accountancy and Telegraphy Business Management DO YOU ASSOCIATE COLORS cept Law Four volumes, 1728 pages and Ten volumes, 3680 pages and 21100 illustrations, platea and 1987 illustrations, forms, etc. WITH FIGURES? and Practice, diagrams. Prepares for Tele- Prepares for Certified Public phone Engineer, Wire Chief. Accountant, Auditor, OtBce The recent letter to Science from David which is Exchange Manager, Trouble Manager, Accountant, Credit Starr Jordan called to my attention a fact Man or Telegrapher. Regular Man or Bookkeeper. Regular bound in law price, SCO.Ou.Special price, S12.S0. price,$50.00. Special price, S24.S0. which I did not know before, says Arthur buckram) and Bessey Smith, the well-known telephone engineer, in that journal. On mentioning stamped in it to my laboratory assistant, Mr. Herbert gold. Fill out One Edward Clapham, he said that he, too, as- the coupon. sociated colors with the letters of the al- Week phabet, but not with all, and that figures Automobile Steam and Gas Engineering were also associated with colors. At my Engineering Free volumeg, :i400 pages and Seven volumes, 3300 pages and the following list: Five request he wroje out 2000 illustrations. Prepares for 2600 illustrations, plates, dia- Prepares for Sta- A gray O black 1 white Garage Foreman, Automobile grams, etc. Meclianic or Chauffeur. Inval- tionary, Marine or Locomotive Trial B light red P brown 2 red uable to car owners. Regular Engineer or Fireman. Regular C black Q 3 light red price,$26.00. Special price,S17,80. pricc,S35.00. Special priee,S21,80. We*l! gladly send you any set for D pink R 4 gray MachineShopPractice Law and Practice seven days' examination. Don't send E scarlet S white 5 white and (with Reading Course in 25 Six volumes, 2300 pages US a penny; just pay the small ship- F pink T red 6 white 2500 ill'strations. Prepares for bound pamphlets). Thirteen Machine Shop Superintendent volumes, 6000 pages and 24 illus- ping charge when the books arrive. G U golden brown 7 golden or Foreman, Foundryman, Pat- trations. Prepares for all Bar Examinations. A wonderful carefully use them yellow \' gray 8 brown tern Maker, Tool Designer or Examine them — H Tool Maker. Regular price, aid to business men. Regular Special price .$39.S0- at your work for an'entire week. At I white W 9 red .530.00. Special price. S19.S0. priee,$72.00. the end of that time, if you feel they J white X —• black Sanitary, Heating and PracticeJ aren't worth far more than we ask, K Y white Engin'ring Accounting Ventilating return them at our expense. If you keep Four volumes. 1840 pages and L Z red Four volumes, 1454 pages and them, pay the bargain piice on the easy more thun 1400 illustrations, 800 illustrations, plates and explained below. M olive green etc. Prepares for Sanitary diagrams. C. P. A. questions terms N olive green Engineer, Heating and Venti- and practical problems. Pre- lating Engineer, Master pares for Accountant, Book- American technical Society Altho I have never associated colors Plumber or Plumber. Regular keeper or Cost Clerk. Regular Special price.$I3.S0. price,$20.00. Special price,$12, 80. Depr. X3389 Chica^Or U. S. A. v/ith letters or figures, from my earliest price,S20.00. recollection I have always thought of let- AmericanTechnicalSocietyr Dept. X3389, Chicatior III. ters and of figures arranged in certain SOc A WEEK r Pleasi" Bend n le set of., the set you I relative positions. The origin of this I do Yes, if you decide to keep for 7 days' «'xa ill within have selected, send $2 within seven | thoroughly and. if satiBtied. send $2 not know. It might have been something month i50c a week) days and then $2 a | have paid the epecial price of. If I decido not to keep the books, I will return them by express st your expense. Title not to pass to oie until in the presentation of these things by my until the present low^ price has been tho | | aet is fully paid for. paid. Have you ever heard of a more first teacher, or the manner in which little | generous offer? Remember, you take . wooden sticks were laid out on my desk no chances whatever— we send the books for | in the first number work. These little examination and you are not obliged to keep them if you do not care to buy. Mail the sticks, each about 3 mm. in diameter and coupon HO""— before you turn the page. I 20 mm. long, had been split out of pine for .-'.'J me by my father.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 660 ELECTRICAL EXPERIMENTER January, 1919

ZllllllllllllllJIIIIIIIIIIIIIIIIIIilllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll^ *? CHEMISTRY! We present herewith to our friends our new EL L Co. Chemical Laboratory which contains real chemicals and apparata to perform real chemical experiments. This outfit is not a toy, DO YOU KNOW? put up merely to amuse, but a practical laboratory set, with all I the chemicals, appuata and reagents necessary to perform = Do you know how to make chemical tricks? real work and to teach the beginner all the secrets of inor- ^= Do you know how cloth is bleached? gfuiic chemistry. With this outfit we give free a book con- Do you know how to test soil? taining a Treatise in Elementary Chemistry, useful data and = Do you want to make invisible ink? recipes, and 100 instructive and amusing experiments. — Do you know how to test flour? Do you SS know how Chlorine Smoke and 44 ^= Chlorine Gas (German War Gas), is made? I ^^ What do you know about chemistry in gen- Chemicals = eral? | ^— These and hundred other interesting ques- 17 SS tiona are answered and demonstrated with our I ^^ Chemistry Laboratory which we present here- Apparata ^^ with. g

The chemicals furnished are all tech- Instruction 5 nically pure amd put up in appropriate Book with wooden boxes and glass bottles, and ^ there is a sufficient quantity to maJce 100 Ex- I dozens of experiments with each. The periments apparata are of standard laboratory size | and quality. Altho all chemicals have nearly dou- PRICE I bled in price, we have decided not to raise the price for this outfit for the $5-00 present. I Shipping = Read the list of chemicals and apparata Weight 10 lbs and look at the actual photograph of M the outfit at your right. CAN BE SHIPPED = And order one today! BY EXPRESS ONLY =

THE E. I. Co. CHEMICAL LABORATORY DESCRIPTION OF THE OUTFIT It contains the following 44 chemicals: Ammonium Chloride Brimstone Ferrous Sulphate Iron Chloride Alum Iron Oxide Nickel Sulphate Calcium Oxide Antimony Sulphate of Zinc Sodium Phosphate Stannous Chloride Boracic Acid Magnesia Carbonate Zinc Carbonate Nickel Chloride Charcoal Zinc, Metallic Ammonium Sulphate Hydrochloric Acid Sodium Nitrate Sodium Bicarbonate Ammonium Carbonate Sulphuric Acid Sodium Carbonate Sodium Sulphate Ammonium Aqua Iodine Sodiam Borate Sodium Chloride Calcium Chloride Mercury, Metallic Sodium Sulphite Calcium Sulphate Chloride of Zinc Tin, Metallic Manganese Dioxide Barium Chloride Copper Sulphate Litmus Paper Oxalic Acid Lead Acetate Glycerol Ferrous Sulphide The following apparata are furnished: One Standard Waahbottle Six Assorted Test-Tubes Glass Tubing One Alcohol Lamp One Test-Tube Holder One book containing Treatise on One Conical Glass Measure One Erlenmeyer Flask Ten Sheets of Filter Paper Elementary Chemistry and 100 One Class Funnel One Glass Dropper Chemical Experiments to be per- One Delivery Tube One Spoon Measure formed with this outfit. THE ELECTRO IMPORTING Co., NEW YORK, ^^^^t°^ SEE OUR FULL PAGE AD ON PAGE 679 FOR FREE CYCLOPEDIA s

You beneHl by mentioning the "Electrical Experimenter" when tvn'fttv to advertitert. January. 1919 ELECTRICAL EXPERIMENTER

Before disclosing your invention to anyone send for blank form "Evidence of Conception" to be signed and witnessed. A sample form together with printed instructions will show you just how to work up your evidence and establish your rights before filing application for patent. As registered patent attorneys we represent hundreds of inventors all over the U. Edited S. by H. GERNSBACK and Canada in the advancement of inventions. Our schedule of fees will be found In this Department we publish such matter as is of interest to inventors and particularly to reasonable. The form "Evidence of Con- those who are in doubt as to certain Patent Phases. Regular inquiries addrest to "Patent Advice" ception," sample, instructions relating to cannot be anwered by mail free of charge. Such inquiries are publisht here for the benefit of all obtaining of patent and schedule of fees readers. If the idea is thought to be of importance, we make it a rule not to divulge all details, in sent upon request. Ask for them,—a post order to protect the inventor as far as it is possible to do so. card will do. Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches and descriptions must be clear and explicit. Only one side of sheet should be written on.

Readers' attention is called to the fact that have been superseded by automatic soap dispensing LANCASTER ^IUll due to the great amount of letters to this de- machines, such as liquid soap, where you only have partment it is quite impossible to answer them to press a button to get a thimblefuU of liquid all thru these columns. The inquiries answered soap in your hand, or the other device whereby 255 OURAY BLDG., in this issue date as far back as July, and if you turn a handle which puts soap shavings into readers wish speedy service they should care- your hand. WASHINGTON, D. C. fully note the announcement appearing in the Invisible Periscope. preceding paragraph. (292) Mr. Geo. Ulrich, _ Newark, N. J., sub- mits an idea of what he calls "invisible periscope'* Code Practise Instniment. scheme. The outside of the periscope tubing is (289) Geo. R. Griffin, Troy, N. Y., writes: to be surrounded with a heavy glass tube while "I have noticed in the November number of the the space between the periscope tube and glass Electrical Experimenter an article by A. E. tube IS to be filled with sea water. The periscope Kopp, New Middletown, Ind., called 'Code Prac- tube is to be painted to match the sea water. Our advice is tise Instrument' and the fault you had found asked. PATENTS A. with it. I have an idea which might be of value While an ingenious idea, this is not different from many other similar to Mr. Kopp's instrument, dnd am enclosing copy devices which INA'ENTOBS. Send U3 a sketch, model, or of same with the request to publish the device at have been suggested in the fjast. The trouble photo and written description of your invention your convenience." is that it is not the periscope itself which makes for advice regarding patent protection. No charge for this service. Mr. Griffin suggests putting the lamp of the the trouble, but the V-shaped wake of churned, practise outfit right on the key lever as shown white water which is left behind as the submarine Patents we secure advertised with- speeds thru the in our illustration. By this means the bulb is water. The periscope itself can be out charge in Populsu* Mechanics Maga- screwed in the socket made for that purpose on and has been camouflaged m the past in such the lever of the key. This has a tendency to a way as to render it almost invisible within a zine. experience. Prompt light the bulb on the downward stroke instead of hundred yards. Of course, this is all right while 20 years' personal service. Our the the upward stroke. submarine is not moving, but once it starts experience and knowledge in patent matters often advise regarding A. This strikes us as a good solution of Mr. moving, the periscope immediately leaves a tell- enables us to patentability without tale the inventor. Kopp's idea, but of course in this case Mr. Grif- wake behind. expense to Particulars Free. Write today. fin and Mr. Kopp should really be joint inventors us in any future patent action. The solution seems Ice-Cream Cone. TALBERT TALBERT, Patent satisfactory offhand. & Lawyers (293) Gardner S. Wyman, Pittsburgh, Pa., 4287 Talbert Bldg., Washington, P. C. says: "I would like to submit a plan for a paper ice-cream cone that is to take the .Bufi) place of cake cones now in use, as I understand there is a shortage of the latter; the plan is to make a cone PATENTS of the same shape as cake cones out of fairly heavy wax paper, the. latter to unroll like a paper Inventors Invited to Write for Information pencil as the cream is eaten away." Our advice and Particular* IS asked on this idea. Highest References. A. Best Results. We are afraid that while it looks feasible Promptness Assured. on paper, it would not work out in practise for the reason that it would at best be a very messy WATSON E. COLEMAN operation to thus unroll the wax paper, which Patent Lawyer surely would splash melted cream over the eater. 624 F Street N. W. Washington. D. C. Improved Code Practise Instrument. »< Diving Mine. (290) W. F. Ashe. .Incl:s.-nvillc. Fia.. writes: "Has there been a patent issued for a 'diving mine'—power to be furnished by small motor or TRADEMARKS clockwork—one that will take in water on the surface of the sea, which will cause it to sink to let mine rakes pass by, and after it has gone copyrTghts down to about fifty feet, it will throw out water, and thus cause it to rise in time to blow a battle- ship up?" Before disclosing an invention, the inventor sliould write for our blank A. To our knowledge there has never been _ form "EVIDENCE OF CONCEPTION". This should be signed and witnessed anything of this kind invented before, and we and returned to us together with model or sketch have never seen any reference to it. We think and description of the invention, a device of this kind is more or less impossible. and we will give our opinion as to its patentable nature. Our Illustrated Guide* Book, HOW TO OKTAIN A PATENT, sent Free on Safety Soap. request. Contains full instructions regarding Patents, (291) W. L. McGonan, Holdenville. Okla., Trade-Marks, Foreign Patents, writes: "To your knowledge has there been any Our Methods, Terms and 100 Mechanical Movements illustrated and de- device patented for preventing soap from being scribed. Articles on Patent Practice and Procedure, and Law Points for inventors. stolen or destroyed from public places? Further- An actual search of United States patents made in all cases before preparing application for patent. more what do you think of such a device. The Electrical Cases a Specialty Highest References Prompt Attention device which I speak of is composed of a flat Reasonable Terms steel which runs thru the center of the soap and is fastened by chain at one end and small lock FREE COUPON! on the other. Any information that you can give me concerning this matter will be greatly VICTOR J. EVANS & CO., Patent Attorneys appreciated." Pittsburgh Offices: Philadelphia Offices: 1001.nr.. to.'^'inn^°J/''1007 Woolworth".'"''L^- o... A. This is a very old idea, and one which we Bldj, 514 Empire Bldg. 135 S. Broad St have seen in actual use in hotel and public wash- Main Offices: 779 Ninth Street, N. W., Washington, D. C. rooms years and years ago. There is nothing 'Vo^ie Address novel about this, and nearly all of these devices

Vr,,, here/it by mentioning the "Electrical F.it>crimcnter" when writing to advertisers. .

662 ELECTRICAL EXPERIMENTER January, 1919 Electric Radiator. NEW ELECTRIC FIRE DETECTOR (294) Earl F. Hobbs. St. Louis, Mo., has an AND ALARM. idea of a hot water radiator^ electrically heated wilh expansion tank and built on wheels so it The new quick alarm fire detector here could be moved from one location to another shown supplements and supersedes watch- and from room to room. It could made be out men. It is superhuman in responsiveness, of % inch pipe with about a 500 watt element made from nichrome wire. The radiator to have a medium and a low point. A. There is nothing fundamentally new in electrically heated water radiators as our cor- respondent suggests in his letter. We have in the Electrical Experimenter often described numerous electrically heated radiators of this sort.

MILLIONS Poison Shell. (.295) Joseph Vicrthaler, Philadelphia, Pa., sub- ./v% OF DOLLARS mits description and device of a poison shell which comprises an ordinary shell with a hollow center. MT> being spent for new NOW Poisoned gas is enclosed in the shell, the latter Ideas of all kinds. Never before is in hu the demand for good illinss put the shell when manufactured. Our PBOTETTED BY 0\VBN V'AT- advice is asked. NTS bt*n so great —or profitable A. There is nothing new at all about this, and to the mao who will but use hi? the present gas shells as have been used by the brains. Send for my four free books and And Germans as well as all the Allies the out what Inrenllons are needed. and United States are made along precisely this plan. fc.rrrEsSFrL patents— a THESfAREfRfElfF',page ffulde to guccesi: STEPI'ING STONES— hundreds Of hints of Ideas waiiiid. tm*h alKiut prizes for Inveii- Fan Guard. UoD«: PATENT BrTERS—eontalna oter 400 (296) Ladimir H. Svoboda, Cleveland, Ohio, requests for OWEN I'ATEN'TS, with Ideas de- writes: "As editor of the 'Patent Advice' I sired: PATEN'T PROMOTION— tells how to would appreciate your advice on the following; ell 70ur patent, etc. Would it be advisable to employ a guard for a 1*11 help wllhout charge to sell your Idea small special electincal fan having blades but 3" br adTortlsing It and otherwise putting you In long? The guard if employed dissectable. toocb with pTOspertlTe buyers. Send sketdi or must be model for fre« opinion a» to patentability, cnat I have been advised to use a 'sand guard.' Could oC patent, etc Adrlce cc^ts nothing. Write you give mc details as to this or any other dis- to

You beitefl by mentioning the "Electrical Experimenter" when writing to advtrtitert. :

January. 1919 ELECTRICAL EXPERIMENTER 663 ONE READER'S EXPERIENCE WITH DR. ABRAMS' THOUGHT TRANS- FERENCE 'Answer the calL THEORY. As our reader's will recollect, we sug- oflbur CdltinyNoM gested in the September issue in connection with the article therein entitled "Popular Demonstration of Thought Transference F you like electricity and are electrically inclined—there is and Other Phenomena," by Dr. Albert is where you will be most successful ; for electricity Abrams, that they write us as to what suc- your calling. And the great field of electricity, with its cess they have attained in conducting any superior advantages, opportunities and possibilities is of the experiments outlined by Dr. Abrams calling to you now. Answer that call by obtaining the in this little known realm of science, and thorough, complete and practical electrical education, we are pleased to give herewith the views training and development this school offers. You will need ability because of Brooklyn, N. Y., of Mr. J. W. White only electrical men with ability are chosen for the high electrical places. But having witnest a number of these Mr. White don't just work at electricity, learn electricity. Don't just be ambitious. Fe tests as conducted by Dr. Abrams himself, determined to succeed as one of the thorough efficient electrical men so when visiting San Francisco several years anxiously sought. Enroll with this school now—don't wait and waste your ago. Furthermore, Mr. White, who is in time. the electrical business in New York City, and a thoroly wide-awake student of electrical and allied matters, had the satisfaction of taking part in some of the experiments in Dr. Abrams' laboratory, and his Become^n Elecirician In One Year Here views as given below are those of an un- \ prejudiced and unbiased student OrLearn ^n E/ectrical Trade in 6 Months s Many people undoubtedly who have read the article in question have tried, unsuccess- THE courses here are practical, with the essential theory, mathematics, = fully perhaps, to obtain results by unipolar drafting, etc. You will have electrical appliances, tools, instruments, s currents, according to the theory of Dr. machines, motors, generators, etc., to work with while learning, to g Abrams, such as for instance where the design, build, repair and operate—learning by actually doing as well as from g "percipient" or person interpreting the classroom study and lectures. Also, there are fully equipped laboratories ^ thought transference signal or message is here—students performing 383 experiments a year. And you will obtain here s which - connected to another person or body in a short time the electrical knowledge , ^ forms the exciting point in the unipolar and ability the electrical world requires, /yd// l/llS COUDOrT (single wire) circuit. which you will need to succeed. Here, for example, is what Mr. White You Can Earn While You Learn School of Engineering experienced, and in this connection it is All your school periods here will be confined to of well to remember that the high professional Milwaukee morning or afternoon—with a half day free. And, 73-373 Broadway, Milwaukee. standing of Dr. Abrams in the medical and if you choose, you can work one-half day at good Wis. all of any pay in a position provided you by this school. scientific fields precludes doubt I have checked the And thus you can earn while you learn and help subjects I am in- fake or misrepresented reactions or phe- terested in please defray your school expenses and obtain, as well, — send complete de- — tails. nomena, however little we may as yet know the valuable experience by working. Evening classes

I gtotrlclan as to the exact mode in which such phe- are likewise conducted and you can work all day Coorea A. C. & D. C— 1 yr J Electrical EnKlneerlng Course 3 i and earn more money, if you prefer. Clip the coupon — yean nomena take place. First Dr. Abrams 6 months Electrloal Trad, Courses r at the right here get catalog and details of this — 1 Electrical Trouble and I.lneman in separate laboratory Learn" plan placed Mr. White a school's courses, the "Earn While You \ Electrical Metenuan. advantages here for you. Clip and Electrical Wlreman. permanent steel bar \ and the many 111' room and gave him a Electrical = mail the coupon. Motor aad Generator Becalr- magnet, which as we all know has a North man. 1 Telephone Trouble and and South pole at the alternate ends. The Bepalrman Next Term Starts January 2 1 Draftsman. Doctor instructed Mr. White to present : ] Earn While Tou Learn Plan either magnet pole as he might elect to the Department of Practical Electricity Name. steam radiator in the room, when he would be able to tell in his instrument laboratory SCHOOL OF ENGINEERING Address just which end of the magnet he had pre- ^^cS^SosHtuu OF MILWAUKEE sented. According to the theory of Dr. City state. r 73-373 Broadway, Milwaukee, Wisconsin. Abrams, the action here was as follows Aae Education That the electronic discharge from the magnet, even when held a short distance iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiifiiii""^ from the radiator, charged the metal piping system, and this particular discharge past along thru the radiator and metal piping to at AMERICA'S PIONEER AVIATION the laboratory where an instrument or a SCHOOLunder Former Aviator Of- human substitute for the instrument was LEARN TO FLY ficers Back from the Front. connected by one wire to another radiator We are NOW enrolling Student Aviators connected to the system. In this connection for our SPRING CLASS which start. it is interesting to note that Dr. Abrams March 1 at. (Members of Aeronautical Society of America) usually prefers to employ some delicate hu- used for "-alnlng. man reflex, such as the heart or stomach Modem type, high speed biplanei indicating reflex, for when one of these ex- talned from AKBO CLCB OF AiLERIOA. BTeatjer than tremely minute electric currents arise, and opportunltlea for Licensed A'latora are The ot fast trana- the Aeroplane Is now the means which agents he claims are' many hundred mer tor express goods. SJrtitlon of maU. passengers and lUht training in thousand times more sensitive to minute Course, also includes 6 weeks Our Flying of Instru- operation of engines, airplanes use currents than are the most delicate scien- "are Sd eUi. ments, map reading, nadgaUon of the air. tific instruments such as galvanometers, etc. Telephone Bryant 9078 Booklet -Tl-'-'-A Message Writewnie forlot uu.our lUustrated York To sum up this experiment. Dr. Abrams was ^^ ^^^ ^^ AnaUon." 110-114 West 42d Street, New able to tell quickly just which magnet pole Mr. White had presented to the radiator, not making a single miss in twenty tests. ACTIVE SERVICE- One of the most astounding phases of this particular experiment was when the Doctor informed Mr. White that it was not at all necessary that he present the magnet to the radiator, so as either to touch it or approach close up to it, but that he could determine which pole of the magnet the in- 1 i^lE-m-^pi-^f'lnk-J/t^ IrScs S. . New Yor. vestigator was thinking of if he would but 'K?fe2ffi"!i^- lay it on the floor and concentrate his mind ExPerime.tef when siting to advertUers. Ynu teneM by meniio.ino the Electrical J —

664 ELECTRICAL EXPERIMENTER January, 1919

on one of the poles. This experiment was checked up by a considerable number of Learn Telegraphy-Wireless tests, and Dr. Abrams was able to tell the pole concentrated on in Mr.- White's mind ^ Right In Your Own Home, in your spare time ^^ each time. One of the experiments which will inter- Remarkable opportunities are offered experienced wire- est our readers very greatly, especially those is greater less operators and telegraphers. The demand who read the article referred to in the than the supply—steady positions at increased pay and September issue, was that where Mr. White rapid advancement are assured. became the "percipient." To show the effect of the electric currents in the body. Dr. Combination Abrams had a strong man placed in a sep- IfS >^ 4.i!lj. arate laboratory, several rooms away from YA Wireless-Telegraphy v/Utllt where Mr. White was located, and both this man and Mr. White were connected by a I .,, will soon make you an accomplished opera- single copper wire. A number of heavy tor. Teaches Light and Sound Signals, both weights were placed in the room with the Radio and Morse. Outfit consists of ex- strong man. The percipient—Mr. White ceptionally fine Telegraph Key, Buzzer, 3 liad attached to one of his fingers a pulse Binding Posts, Lamp, Lamp Socket and detector of these minute electronic currents, Control Switch—all mounted on a highly as devised bj' Dr. Abrams, comprising a finished base. Two outfits can small rubber tube strapt to the finger ; this ^ ^^ »""^^ tube being connected by means of a rubber be operated at considerable • B Jjj tube with a small pneumatic chamber at- distance apart for sending and ^ tached to a pivoted arm, the free end of receiving practice. 3 which carried an electric contact for opening and closing a signal circuit. The con- This Outfit Without $2.50 Same Lamp tacts on this instrument were conected with battery and electric signaling bell. Or your dealer can secure it for you. Order to-day. Descriptive circular and a an catalog of celebrated Knapp Motors and Electrical Specialties from 10c up This pulse indicator was connected and mailed free on request acted in the same way, upon the receipt of each electronic wave or current, as the Knapp Electric & Novelty Co., 523 W. 51st St., N. Y. straw pulse needle indicator described in the article referred to.

This is what happened every time the strong man lifted the weights in the distant

part of the laboratory buildings : An elec- BECAUSE OF THE tronic current apparently shot along the wire and acted to cause a heart reflex in the percipient's (Mr. White's) body, which SHORTAGE of CRUDE RUBBER manifested itself at the pulse, and in turn this action repeated itself thru the rubber You can SAVE ^\^-^^ on our Standard tube attached to the finger, thus causing the pneumatic diafram chamber to vibrate and move the pivot arm attached to it, which in turn caused the electric signal bell to ring VIOLET-RAY MACHINE each time a weight was lifted by the "agent." Beiof afraid that we could oot get delivery on bard rubber used for the outside casing of the Violetta machine, we made aso of these in wood. Now these machines are exactly alilce in construction mechanism Probably some of the most remarkable and workmanship as our latest model standard machine which costs ^2$.oo. tests which Mr. White personally saw per- The only difference being that instead of usinjg hard rubber formed by Dr. Abrams were those where for casing, wood is used, but it is finished in a beautiful the he was enabled to differentiate between dif- black piano finish, and the difference is hardly noticeable. ferent disease germs, and in cases Now, we cannot send these out as standard machines so are some placiot them in a special lot at even the disease affecting a patient over a telephone or other wire. For some of these $is.oo and other tests Dr. Abrams has devised a an actaal Mvins to you of $10.00. Besides we guarantee these very interesting instrument to take the place macbiaea to be new. The Out£t includes the generator, one general electrode and a handsome carrying case. of the stomach reflex, thus doing away with How to secure one of these machines: ihe necessity of a "live" percipient. This Send only one dollar to pay express charge* and we shall instrument comprises an aluminum cylinder send you one of- these instruments by express for your ei- covered at one end with a tightly stretched aminatioQ. This amount will be deducted from total cost of diafram of goldbeater's skin. metallic machine. You need not accept if not satisfactory. The bell or rather shell of this instrument is S and pneumonia have their own vibration 13 weeks on tn.^l. '1 hr Paihlimler Is an itlustraiei:! weekly, puhlislied at nvrt-e center of citilization; history is htrtng the Nation's c^-ntct. for tht Niitiun; a paper that prinu all the news of the period or wave length, according to his mode at this urorid capital. The Pathfinder's world and tells the truth and only the truth :now In its 26th year. This pa- illustrated weekly review gives yoU a clear, int' most remarkable work, "New Concepts in per (ills the bill without emptyingr the purse: It costs but Si a year. If you partial and correct diagnosis of public affairs want to keep posted on what Is Eolnff onlnthewnrld, at the least expense Diagnosis and Treatment." during these strenuous, epoch • making days. He outlines of time or money, this Is your means. If you want a pripcrin your hone ruiDitii. wh'.lesoriie. (be Pathfinder Is yours. If you would appreciate a paper which puts everything forms of wireless tuning aparatus compris-

clear'.y UirV . It Sen-1 «5c to show thatyothat you miifhtlike suchapaper._and we will scn;1 the I'-iih finder on probation 1 ing condensers, tuning coils, etc., for the T5.e IJ. -i'^cs D-Jt repay u&, but we are triad tolnvcs Id new Iricnds. Th* Pathflndttr, Box 79 « Washington, D. C. purpose of measuring the exact wave length or vibration index of these electronic currents as they are received over a telephone TYPEWRITER SENSATION or other wire and interpreted by the instrument just described, or by recourse to a hu- PROMPT SHIPMENT. man percipient employing the stomach or $4.00 per month buys a beautifully reconstructed, latest model visible other reflex. The stomach reflex is one in typewriter, with back spacer, decimal tabulator, two-color ribbon, etc. which the percussion sound given by the Kvery late style feature and modem operating device. Sent on approval. Catalogue and special prices free. stomach when struck with the fingers over that portion of the body is dulled when an Harry A. Smith, 738, 218 N. Wells St., Chicago, 111. electronic current is received.

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EXPERIMENTER 665 January. 1919 ELECTRICAL

or when Sec. 6. That when the United States la at war the United WIRELESS SITUATION. war is threatened, or during any war In which THE national emer- Suies is a neutral nation, or during any (Continued on page 625) geno-. such fact being evidenced by the proclamation of the President— , , , the.v. con-„« companies having been suspended, and (a) The President may ls=kue regulations for ness of all appa- having made an instant show ol duct and censorship of all radio stations and radio their operators States or of any in the earliest ratus within the jurisdiction of the United patriotism by joining the Navy knowingly violates any such of the of its possessions. Whoever days of the war. it is believed that n:\o.st punished by a fine of not more than glad regulation shall be companies owning radio stations would be $10,000 or by imprisonment for not more than three years, radio sUtion or at this time to sell their stations to the Oovern- or both, and in case of any violation the provided for in the apparatus shall be forfeited to the United States; and ment at a fair price, which is radio (b) The President may cause the closing of any BWS since all who have made a bill; especially so, land or on a permanently moored vessel within radio communi- station on study of conditions under which the jurisdiction of tiie United States or any of Its posses- apparatus, cation is held must realize that it is only a ques- sions and the removal therefrom of any radio or Its apparatus tion of time when Congress will enact some meas- or may authorize the use of the station United States. to this. by the ^. , ^, ure similar regulations for the conduct and censorship of radio of the world is to De The At this time, when most stations, the closing of a radio station, and the removal of made over, when the United States is fostering apparatus therefrom shall continue no longer than the the beginnings of a great merchant marine, duration of such war or emergency. The fact that the shall be evidenced by the whose servant radio-telegraphy is, and when the war or emergency has ended news and American viewpoint are to proclamation of the President. American Sec. 7. That if, in the opinion of the Secretary of the nations, it it. be disseminated throughout the Nav>'. the operation of any radio station would Interfere submitted that the greatest good to the people with the receipt of signals by radio stations belonging to government of the Philippine of the United States as a whole will accrue to the United States or the communications with Islands, or by radio stations on shipboard, or would be them from well-regulated United States, with foreign nations at otherwise prejudicial to the interests of the their ships at sea and no license under the Act entitled "An Act to regulate radio reasonable rates without inteference from a va- communication." approved August thirteenth, nineterai hun- riety of rival interests within our own borders, dred and twelve, shall be Issued to such station, and any such station shall be revoked utilizing the system of stations which is abso- such license alreadv issued to or suspended for such time as the SecreUry of the Navy lutely necessary for the control of the Fleet. successful naval opera- mav prescribe. There is no such thing as Sec. 8. That when any radio station is requisitioned, tions these days without efficient radio commu- taken possession of temporarily or permanently, or closed, nication, and this must be provided by stations or its license revoked or suspended, the United States shall Drafting for Learn smoothly and efficiently in the hands of pay to the persons interested therein just compensation running provided that a claim for Government long before hostilities actually the property or interest so taken, the such compensation is made on the Secretary of the Navy, The United States Government and employers commence. within two vears after the date of passage of this Act. draftsmen. , ,. ^ . r everywhere are looking for skilled Department has the confidence of case of disagreement as to such just compensation, the The Navy In They are offering splendid salaries, and still eood and of the people of the United States, Secretary of the Na^-y shall make an offer, and if such offer Congress the positions are always open, because thousands of deserves the confidence which would be IS not accepted there shall immediately be paid to and person interested three-quarters of the amount offered. draftsmen have gone into the service. Others it through the enactment of this very placed in The person interested shall be entitled to sue the United must take their places and carry on their work. necessary measure. States to recover the balance justly due. in the manner advance- provided by section twenty-four, paragraph twenty, and No line offers greater opportunity for section one hundred and forty-flve of the Judicial Code. ment Drafting itself not only commands good An amount sufficient to pay such just compensation Is pay, but it is the first step toward success in Me- FATAL BILL. appropriated any money in the THE hereby permanently out of chanical or Structural Engineering or Architec- Treasury not otherwise appropriated. drafting is just the kind of work a boy iQiCQ 65th CONGRESS. Sec. 9. That all radio stations taken possession of by ture. And . K. lî:>y. in H-p 2d Session. the President shall be operated under the direction of the likes to do. There is an easy delightful way IN THE HOUSE OF REPRESENTATIVES. Secretarv of the Navy. which you can learn right at home in spare time. Sec. 10. That the Secretary of the Navy shall, so far as For 27 years the International Correspondence November 21, 1918. the transactions of Government may be consistent with Schools have been giving boys just the training introduced the following bill; business, open naval radio stations to general public busi- and more than Mr. Alexander prescribed him and shall fix they need for success in Drafting the ness under regulations by which was referred to the Committee on the rates for such service. He shall establish special rates 20Oother subjects. Thousands of boys have stepped to Merchant Marine and Fisheries and ordered for the handling of press dispatches by transoceanic or into good positions through I. C. S. help, but never be printed. other special stations. The receipts from such services, opportunities so great as now. twenty-flve centum per were A BILL less an amount not to exceed per you annum for expenses, shall be turned into the Treasury as Let the I. C. S. help you. Choose the work miscellaneous receipts. and mail it. To furllier regulate radio comiuunicalion. „„„„„ ^„ like best in the coupon, then mark BE IT ENACTEi) BY THE SENATE AND HOUSE OF doesn't obligate you in the least and will bring OV This REPRESENTATIVES OF THE UNITED STATES you information that may start you on a success- IN CONGRESS ASSEilBLED, That whei used AMERICA ful career. This is your chance. Dont let it slip this Act In this coupon now. The term "signals'* means the signals used in communi- BROWNING GUN SUCCESSFUL IN by. Mark and mail cation by any electri ;al system or method without the T EAR OUT Aid of a wire or other conducting connections; AIRPLANE PROPELLER TEST. The term "radio station" means any place, vessel, or INTERNATIONAL CORRESPONDENCE SCHOOLS •vehicle containing apâraû3 used, or capable of being used. The Browning machine gun has success- for transmitting or receiving signals: BOX 6171, SCRANTON. PA. radio station fully test to determine its The term "eiperiment station" means a undergone a Explain, without obligating me. how I can qualify for the experiments for the develop- actually used for conducting aircraft. is of position, or In the subject, hefore which I mark X. communication or the appa- value for use with This one ment of the science of radio DRAFTINI GSALESMIXSIIIP ratus appertaining thereto, and used for no other purpose three types of machine guns with which MECHAMCAL schoul station STKlCrURAL KRAFTlNtJ DAUYEKTISINd except as a technical and training Show Card Writer "technical and training school station" means the rate of fire can be so synchronized that -SIIII' DRAMISU 3 The term Sign Painter purposes of instruction in radio EI.KCTKKAL MRAFTINO 3 a station actually used for the gun can be fired by the pilot of a DRaKTKNO DlLLCSTUATINO communication and of training operators, and used for no AHCIII lECriRA!, _S11F.EI METAL ItHAFTINU DCarrooning other purpose except as an experiment station combat plane thru the revolving blades. UBOOKREErER The term "person" includes partnerships, corporaUons. U HlliLERMAKEK imAKTl.VO in that fashion, it is necessary to OStenoKraphtr and Trplst associations. Firing imilXiE liltAFTI>G and Cert. Public Accountant the President shall reauisition and Uite MINE i)Esn;s Sec. 2. That aim the machine gun by steering the plane B)1A< 5IANA<;ER the use of the Govemmeni. ELEtTRlCAl, EN(;iNEEn lUAFFU permanent possession of. for Railway Accountant every radio station on land or on a permanently moored directly at the target. The direction of the DEIecIrlo Liphilng and Rallwars t.StiLl.sll In existence witliln the jurisdiction of the United D Electric Wiring G<;<>«I.\EClt A\0 chine gun is connected with the airplane Teitllo Overseer or Snpt. the jurisdiction of such State or causes interference with L_] Marine Engineer transmission or receipt of signals to or from any place ARCHITECT chemist Uie engine by a mechanical, hydraulic or elec- IDSpanlsh jurisdiction of such State, or (b) for the receipt Contractor and Builder Narleation beyond the B AGRICri.TrUEl^Freneh ot signals which originate outside such State, or (second) trical device, and impulses from the crank Concrete Builder Encinccr Poultrj Italsloglaitallan any radio station within any Territory, district, or posses- shaft are transmitted to the machine gun. Structural sion of the United States. This section shall not apply to experiment stations and technical training school stations The rate of fire of the machine gun is Name duly licensed, as provided by the Act to regulate radio communication, approved August thirteenth, nineteen hun- constant, and its fire is synchronized with present dred and twelve, and stations belonging to the United the revolving propeller blades by "wast- Occupatio:: States or the Government of the Philippine Islands. Street Whoever violates this section shall be punished by a fine ing" a certain percentage of the impulses and No of not more than $600 for the first ofTense. and by a fine it the airplane engine and of not more than $1,000 or imprisonment for not more receives from than one year, or both, for each subsequent offense: and by having the remaining impulses trip or any radio apparatus operated in violation of this section shall be forfeited to the United States. pull the trigger, so that the gun fires just Sec. 4. That from the date of the passage of this Act at the fraction of the second when the pro- the Secretary of the Navy shall be charKed with the execution of the provisions of the Act approved July twenty-third, peller blades are clear of the line of fire. nineteen hundred and twelve, amending section one an of pilot operates the gun by means of a Act entitled "An Act to require apparatus and operators The for radio communication on certain ocean steamers." ap- lever which controls the circuit and allows proved twenty ten. TELEGRAPHY June -fourth, nineteen hundred and with the Act entitled "An Act to reprulate radio communication." the impulses to trip the trigger. It has approved August thirteenth, nineteen hundred and twelve, occurred in practise that as many as IS shots and any amendments to the said Acts, and the provisions AND RADIO at the International Radiotelegraphio Convention, signed have hit the propeller without putting the In London In nineteen hundred twelve and proclaimed Day and Evening Classes in and plane out of commission. by the President July eighth, nineteen hundred and thir- for Army, Navy and Mer- *een, and future International radiotelegraphic conventions Radio which may be ratified by the United States, except in so far chant Marine. Women in spe- as the provisions of the above-mentioned Acts, conventions, or treaties apply to stations operated by other departments cial "Radio Corps". Similar

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

666 ELECTRICAL EXPERIMENTER January, 1919

PHILA. TO BE BIGGEST ELEC- The largest o£ forty-one plants under the TRICAL CENTER. Westinghouse management will be located BE Philadelphia is to be made the largest on the Tinicum township tract near Lester, electrical center in the world after the dec- in buildings now devoted to war purposes. laration of peace, according to plans now Twenty-five thousand men will be employed AN being perfected by the Westinghouse en- at the plant All goods will be shipt ARTIST gineers. from piers to be erected on the tract CHfCK f«oM

O > Experimental Chemistry BY {Continued from page 639) DRAWN Chemical Properties. the body, without heat above that of the 14-YEAR-OLX) BOY rest of the body. In Cuba, a species oi n« ftbOTtt csrtooD mm drawn hj M«st«r Bob Bren- 1. Yellow phosphorous possesses great luminiscent insect is bottled up and used WmahlnjTtoa School of Art. Bob wrltee nm of Uw affinity for of the elements, uniting sometimes for lighting purposes, about that he U Mlhng tTs work and that he U cartoonist many OQ a fzoall pap«r In erapKTUle. Ind. He U but on« with all directly, except nitrogen and Car- forty of these equalling one candle-power of oar many *tudent« and graduaif-s who are mating mooor as cartoonlsu. Illustratcn and desUners. bon. With Bromin and Sulfur it reacts The light is apparently due to an oxidation Learn By Mail at Home violently. Characteristic is its affinity for of animal tissue which is under the control 40° Br our new method of teaching drawing b7 mall rem Oxygen. When exposed to the air at of the insect. To produce the same light own home, 1b a short time. Oet oaD learn Ir rnur C. or at a lower temperature, if in a finely by the oxidation of gas or oil, we have a Into tht« fa«clcallns work rourself and earn $30 to $100 or mor« p«i week I divided state, ignition takes place, burning temperature of about 2,000° F. and 99% of l%e itudr U fasdnatlnA. Only ft few mlnutoa a darl supply the energy Hara rour own itodlo or aeeure hl^-aalarled poal- to Phosphoric oxid, according to the of the flame is lost, while these Uon. Or work In spare time. Manr atxidents mjh of oxygen present. creatures utilize possibly 100% of the while lhe> are learning. CDCCTf BOOK AND ARTISTS' 2. It is luminiscent in the dark, even the energy of oxidation, without any apparent riVHiC. OUTFITl AVRITE TODAY minute particles adhering to the fingers on rise in temperature. The animal supplies oomplete Oatflt fr«t to all amdenu. Inoludea eTery- handling matches. its own light thlng requlrwl to £irodU'*tf h indreds of doIlarB* worth affinity of picturea. Write todar. Special terms to a limited 3. Because of its great for Qtunber of Dew Btadonts. Mall postal or letter for oxygen, phosphorous is an energetic reduc- Uses. tieauilful Booklet. "How to Become an Artist." filled with drawings and full partlculan of our extraordl- ing agent Sulfuric acid is reduced to Sul- larr offer. Do it now before you forget. — fur dioxid. Nitric Acid is deoxidized with Phosphorous is used mostly in the manu- SCHOOL OF ART, Inc. WASHINGTON explosive violence, salts of the metals are facture of matches. A kilogram (2.2 lbs.; 1391 H Street, N. W. Washinifton. D. C reduced to their metals and phosfides, thus of it will tip about two million matches slver nitrat is reduced to Silver and Ag»P, It is also used to some extent for medicinal Copper sulfate to CiuPj. purposes. "I Would Not Part Red Phosphorous. Properties. 1. This is an allotropic modification, and possesses Matches. with it for $10,000 properties essentially different from the yel- So writes an enthusiabiic, grateful/ low variety. It forms a dark red to red- The making of matches after the splint> customer. In like manner testify over| dish-brown powder, which is insoluble in are prepared includes two processes. First, have worn it. KW.OOO people who Con carbon disulfid and all other solvents. It one end is dipt into melted sulfur, some of serve your body and life first. does not Phosphoresce, and is stable in the which adheres to the wood. Second, it if The Natural air. It does not fuse at red heat but when tipt with a paste consisting of a mixture of quickly heated above 260° C. the vapors phosphorous, an oxidizing agent, and glue Body Brace change to those of yellow phosphorous. A little coloring matter is quite frequently Overcomes WEAKNESS and This variety is prepared by heating the yel- added. The oxidizing agent may be Potas- ORGANIC AILMENTS of low variety to 300° C. in closed air-tight sium chlorat [in which case the match snap; WOMEN AND MEN. the and burns vigorously on being scratched! er«i, graceful figure vessels, and after the conversion, prod- Develops I Brings restful relief, com- uct is then treated with carbon disulfid to potassium nitrat, Manganese dioxid, or red fort, ability to do things, remove any of the unchanged phosphorous. lead [PbsO.]. This result is accomplish! health and strength. If a little iodin be added, this change wrill by pressing the end on a slate slab covered Wear It 30 Day» Free take place below 200° C. with the paste. Sulfur is necessary, as the at Our Expense heat liberated in the burning of phosphor- Does away with the strain and pain of standing and Scarlet Phosphorous. Properties. This ous is not enough to set the wood on fire, walking; replaces and supports misplaced internal is another modification, being obtained by abdomen; straightens and coating of PiOs forms over it. organs: reduces enlarged boiling a solution of yellow phosphorous in and a Some- strengthens the back; corrects stooping shoulders; times paraffin is utilized in place of the develops lungs, chest and bust; relieves backache, phosphorous tribromid. It resembles the sulfur. The well-known Swedish [or curvatures, nervousness, ruptures, constipation. red variety except that it is more active, and easy to wear. Safety] match head does not contain phos- Comfortable reducing salts of the metals, and with the Keep Yourself Fit phorous, but consists of a mixture of potas- alkalies, it yields phosphin [PHt] and a Write today for illustrated booklet, measurement sium chlorat and dichromat with red oxid blank, etc, and read our ver>' liberal proposition. hyposulfite. of lead and antimony sulfid. They are Metallic Phosphorous. Properties. This HOWARD C. RASH, Pre*. Natural Body Brace Co. ignited by scratching them on the prepared 286 Basb BuUcUnc SALINA. KANSAS form is obtained by heating the yellow surface of the box, which is essentially a variety in a sealed tube free from air to mixture of red phosphorous, antimony sul- 530° C. It thus forms black metallic shining fid and powdered silica. A machine has crystals, which are less active than the red been constructed to cut the splints, tip the variety. Don't Wear a Truss matches, and dry and pack them in boxes, BROOKS* APPLIANCB. all four processes being automatic 'and con- Luminescence or Phosphorescence. the modem icIentUlc In- tinuous, besides eliminating the poisonous vention, the wonderful new discoverr that re- fumes. If a match is scratched in a dark room, lieres rupture wUl be sent line light may be observed on trial. No obnoxious a faint of A Burning Match. springs or pads. Has auto- as the minute particles of phosphorous matic Air a s h I n s. C which are left glow and oxidize. The sanie Kinds and draws the Whenever one ignites so simple and com- thing occurs if the element is exposed in broken parts together aa mon a thing as an ordinary match, little you would a broken Umb. darkness, and the phenomenon is called does he realize that he is perforrning one .No salres. lies. Dur- No PHOSPHORESCENCE. It is due to slow able, cheap. of the most wonderful and complicated of combustion [or oxidation]. Substances Sent on trial tt prove It chemical experiments. The mere fact that with phosphorous give the same Proiect«d by U. S. Palanta. rubbed fire could be obtained by simply scratching CataJocue and measure blanks effect. less than mailed rrc«. Seod name and the end of a stick was regarded addrew todar. Many other minerals and chemical coin- three-quarters of a century ago, as a truly C. E. BROOICi. 203B State Street. MarshaU, Mich. pounds have the power to emit light in remarkable triumph of science. darkness, and some of these form the basis Friction on the end of a match over a of the so-called luminous paints. The sul- rough surface liberates heat enough to cause TA M M ER ER fides of Barium, BaS, BaSi, BaS., etc., are the phosphorous to unite with the oxygen Yov taa bs ourad qoIcU;. permanaitlr and examples. of the oxidizing agent in the paste, and prlTatelr. Write me perw^nallr for fraa bO(^«t, "How to Stop Siammerlrig-" Some animals, as fireflies, glowworms, et produce combustion, the main product of Samuel 0. Bobbins, Prln.. Bestoi Stanmeran' emit light from a certain part of which is PjOs. If the oxidizer is potassium slostltDts. 246 Huntington Ave.. Boston. Maaa.S cetera, a Yott benefit by mentioning the "Electrical Experimenter" when writing to advertisers. ~

667 January. 1919 ELECTRICAL EXPERIMENTER chloral, then potassium chlorid is left. The heat of the burning phosphorous is enough to set fire to the sulfur, which unites with sulfur dioxid, Disease air to form Treat the oxygen of the Learn to and this in turn sets the wood on fire. The reactions of a burning match are many. Try and complete the following and explain from what each comes, then the This Way next time you strike a match you will probably stop to think of the complicated change This is a small reproduction of one of 22 mag- send which takes place. This only goes to illus- nificent charts all of which we want to just to showyou how trate that many seemingly unimportant you ABSOLUTELY FREE, made during our daily routines easily you can master Chiropractic and how euccessfully operations you can treat disease by this modern drugless healing method. may, if carefully analized, show the com- These charts show the different pain and nerve aieae of plicated changes which take place unob- the body. The science of Chiropractic is based upon the well knowr principle that when there is bone pressure on a trunk served. nerve where it leaves the spinal column there will be pain in the 1. KCLO, = ? 7. PjOs + 3Hj0 = ? area it r:ontrols; and that by reheving the pressure the pain is ban- 2. 2P -)- 50 = f 8. S -H 20 = ? ished. Chiropractic teaches you how to locate nerve pressure at 3. 2P 4- 30 = ? 9. SOa ± H,0 = ? any point along the spinal column and how to relieve it. ? 4. P.O. + H,0 - ? 10. C -f- = 5. PjO, 4- 3H,0 = U. c4-20= ? BE A DOCTOR OF 6. P,0, -1- H,0 - ? 12. C0,-1-H,0= ? 13. 2H -I- 0= ? Phosphates. CHIROPRACTIC Wheat contains compounds of phosphor- Advanced Science of Spinal Adjustment ous, and most food plants in order to come The great profession that within the past few years has taken to fruitage must take phosfates from the the longest forward strides ever known in the history of drugless healing. It has called to its ranks thousands of ambitious men and soil in which they grow. The phosfates women from every walk of life. Today it is calling more insistently must be soluble, so that, as the rain dis- than ever because the tide ha» turned strongly in favor of drug- JeaB healing. Kight now the demand for Doctors of Chiropractic the roots solves it, it can be absorbed by is far greater than the supply. plant. Soils The American University method and circulated in the sap of the f f _ €3.rtl £lt riOmC of teaching enablesyou to study by to be renewed or fertilized, and fer- mail class obtain a have L, , or in and complete mastery of Chiropractic in tilizers contain, among other things, the \y\ Hrtai*^ im^ 111 i.J|jai C X lllic:; ^ê shortest time consistent with soluble phosfate H4Ca[P0.]i, made accord- thoroughness, while you hold your position You can pay on easy enroll your instruction will be under the in reducing the element. terms. From the day you ing to the first step personal direction of a splendid faculty of Chiropractic experts Our This is absorbed, transformed, and assimi- one aim will be to make you successful. We will work whole-heartedly with you to advance your interests so that in a short time you, like lated by the plant, especially the fruit thousands of Chiropractors, can earn a good income. Animals eat the fruit, and thus the compounds of phosphorous are again trans- to a Year posed, circulated in the system, and de- $3000 $5000 are many instances of Chiropractors earning from S3000 to S5000 as in the bones There posited wherever needed, a year. Some upwards of $10,000. Dr. M. D. Moore, of, Kentucky, re- and nervous tissues, and especially in the ports an income of $9,000 a year. Dr. L. H. Roche, New Jersey. $5,000; Dr. Hanna, of Kentucky, over S6.000 yearly. brain. Man feeds upon either plant oY The success of Chiropractors m many cases has come so quickly as to be and thus obtains his phosphorous. Imost startling. And yet, it is not to be wondered at when you consider the animal, nstantly increasing number of intelligent, thinking people who are now con- From the human system it is excreted by ced that Chiropractic is the common-sense and really scientific way to relieve 1 and disease and who. therefore, demand the eervicea of Chiropractors. means of the blood and kidneys, as phosfates and microcosmic salt [HNaNH«PO«]. NOW—Your Great Opportunity When the brain is hard worked, more than Why not qualify now for this splendid profession that offers such re- ttsual is excreted;—in fact, there seems to markable possibilities for making you prosperous and independent? If you to increase your social standing and be "some- be a direct ratio between the amount ex- -.x'-G ambitious make money, iiody. "our course ^^_ ^_^ ^^_ ^^_ ^^^ ^^^ ^ .^^ ^.^ ^_ _^ creted and the vigor of brain action, as Chiropractic tho intellectual effort was attended by .viJI point the way. each No special preli- AMERICAN UNIVERSITY re- the combustion of phosphorous. A simple nnary study Manierre Bldg.. Dept. 372 Chicago, III. .[uired. You gradu- will this. test of the urine demonstrate At .tt? wi'h the deêe Without cost or obligation send roe by mail, your book and your Free Charts the start of the day the urine will, under .f D. C. (Doctor of new illustrated, 72-Dage 'hiropractie), receive offer. normal conditions, appear clear yellow. lianilsome diploma, Examine a sample of urine from the same FREE, and are ready at once to o^tû your ottice. offer at once. Re^lar value taken after a hard day's brain work, p /^L I. subject G-Pr rrPP I charts of the 2Cmagniricent charts is and you will be surprised to see many are handsomely lithographed in life-like colors. Mai! coupon little white specks floating about. This and get all the fact's. We will send vou our beautiful new illustrated book, full particulars regarding course, easy terms, represents the phosphates, and while the R.F.D.. together with free charts offer immediately. Don't put it off Street No. or laboring man may show but little, if any, —mail coupon or send your name on a postal card —today. of these suspended phosphates in the urine AMERICAN UNIVERSITY at the end of a working day, the brain '4anierre BIdg.. Depl. 372 Chicago, III. worker will invariably manifest this condition regularly. To clear the urine in order to test it for any solids or sediment, add a little nitric acid. It will clear up perfectly if the urine is normal.

Experiment No. 147. Place about 12 heads of ordinary (not safety) matches in a flask, as shown in Fig. ISS. Have this flask (1) about half filled with water. Proceed to distill the same by the Bunsen burner under the flask, MSIoRS applying We have 1000 NEW WASHING MACHINE MOTORS. These taking care that the action does not become arc of standard manufacture and carr.v the regular factory guarantee. too violent. Shipped in original l)oxe.s. Complete as cut. If this experiment is performed in a from Bankruptcy Stock darkened room a ring of greenish light ap- Bought Coffee Grinders. Creiuii Scperators. Botlle Washers, pears at the level of the water in the con- Suitable for operating Air Compressors . .. — . denser, where the steam condenses. After ^k^ ^M ^^ Htf ^\ Small Lathes, Mail $3.00 cash or 0* | K/W little colorless spheres of a E^ I I a short time Money Order. We waxy solid collect under the water in the willsL-iidCO.D. suhjct second flask, which acts as a receiver for tu tull examination MONET BACK GUARANTCC Xv^ EACH the drippings from the condenser. If the Rroular Value S34 water is poured away, this solid begins to MAMUFdClOBERS DISTRIBUTER give off a white smoke, and is luminous in GHAS. H, JOHNSTON - West End - Pittsburgh, Pa. the dark. (To be continued) advertisers. y

668 ELECTRICAL EXPERIMENTER January, 1919 KAISER POPULAR ASTRONOMY. highly heated interior and spread out into THE i"i(iiii

/|- Voice Thrower 10c Learu to throw your voice into a TBCNK. under the bed. out in the hall or anywhere. I>.>ts of FUN fooling the Teacher, Janitor. i'ohceman. Farenis, Neinhbors. or Friends. THE VENTRILO k Utile Instrument that fits into the mouth out al^L BOYS or GIRLS can use it. NEVER

_ ILSI A 32-paoe bouk on Ventriloquism seni with the VENTRILO f.^r TEN Cents. NEW FORD JOKE BOOK 1919 All the latest Jokos oa the Ford auto. Hundreds of them, and all good ones. Spring a new one on your neitihbor^. Large bmk tcith colored cover

\ by mail, lOr. IEEE Mors £arff) ' Moon Venus Mercury\

Devil Resigns to the Kaiser

Everyone wim reads this book Is wlM orer it. Contains the following: Diagram I. —Showing ttie Relative Sizes of tlie Four IVIoons of Jupiter, lo, Europa, Ganymede The Kaiser*8 Dream. A Letter from and Calllsto, or Satellites I, II, III and IV Respectively, and the Moon and Terrestrial Planets the Deri I to the Kaiser, Kaiser',-* IMercury, Venus, Earth and IVlars. The Distance from C to S Is the Distance from the Prayer. How Satan Resigns to the "Center" to the "Surface" of Jupiter. if All the Satellites of the Planet and the Terres- K'ng of Dertls, The Kaiser, etc. So trial Planets IVIoon Placed Their Diameters Would Fall any other stories, jolces, etc. about and Were Side by Side Combined ne German Emperor. Book malleil Short of the Surface of the Planet by a Distance About Equal to the Diameter of the Earth. lU cents, postage 2 cents extra. earth, never less than three hundred and The high percentage of light and heat that ROGEN X-RAY sixty-eight million miles, makes observa- Jupiter reflects from the sun to its nearer tions of their surface markings very diffi- satellites would make it a secondary sun Price tremendous size but feeble 10 Cents cult. to them of description strength. seen from the nearest moon HERE. BOYS. Is How beautiful beyond must As Just what you want. ihe heavens appear as viewed from the the other three major moons of Jupiter With this instrument you can in aiii arently see throuKh clothes, see the satellites of Jupiter! From the nearest of present all the phases of our own moon Nxies in vuur Iliii:<.rs. Think of the fun you these, lo, or Satellite I, the mighty planet rapid succession, due to their constantly am hare with .t : Samfk'. l v n:ail, TEN CENTS. Jupiter presents a spectacle such as the changing positions with reference to the SKULL RING eye of man has never been privileged to sun. The five small moons, discovered in IS a handsome, up-to-date behold. huge flattened globe, ninety times, are so minute that they are representing a SkuU and The modern linnes. Has atones In 'he thousand miles in equatorial diameter, equal simply star-like points of light even when ir,.l looks something fright as other moons of Jupiter. Women won't like It, but in mass to ihrce hundred planets such viewed from the n>n or hovs II M a great our own and in volume to nearly fourteen When nearest each other some of the IV Sample, by mail. ISO. fnindrcd, fills a space in the heavens nearly moons appear even larger tlian onr own Gee ! What a Wad ! twenty degrees in extent as viewed from moon does to us, but when approaching op- this satellite. Fifteen hundred of our own disks rapidly This is STAGE MONEY posite sides of the planet their full moons would hardly fill the same space. diminish in size tho they never appear as I.-Kiks like the GENUINE STUFF. Some Green backs and Whirling on its axis with frightful speed small as the far distant sun nearly five Create a feomo Yellow backs. in a period of less than ten hours, the huge I!IG sensation araonR your hundred million miles away whose apparent friends. girls will all be majestically The ball glides rapidly but onward that of the after you when Ihey see the wad. diameter is less than one-fifth thru the sky. A far distant sun shrunk to BIG rnll of 15 pieces by mall, full moon. 10 cents. but one-fifth the diameter of the full moon To keep track of the rapidly changing throws light and shade across the rapidly Boys Toy Maker positions and various phases of the moons Own changing surface of the planet, rich in the and Nine Other Books for lOc (]f seen from p.ny one of ibem, reds, browns and yellows and all the gorgeous Tnpiter as Tells how to make a Telephone. tints of its dense, seething, Mafdc Lantern. Kites. Sail Boat, shades and Stilts, Electric Telegraph. Pop Gun. "gaseous envelope. The phases of the moon Red Fire. Galvanic Battery and many other things. This book, with nine on a greatly enlarged scale rapidly succeed other interesting books, mailed for lOc, each other on Jupiter as the satellite views it from all positions with reference to the :^. ENCHANTED BARREL sun. The cause of the belts of Jupiter, The Moat Wonderful Pocket '^fi Trick Made equator and CHANGE A CENT INTO A DIME that lie parellel to the planet's are constantly changing in number, width Ask y'>ur friend to drop a dime in the barrel. all the peculiar When he ukee it out. Behold I It is a CENT. and shade, as well as of Ynu make U centa every time you fool them. splashes of color and intensely white flecks Never falls. Tboy cannot get on to It. lA^ .sample *Vi. barrel , with directions, only that come and go in the dense atmosphere Any three of the above articles for 2Sc of the planet, could doubtless be explained or any mix for SOc were it possible to view the great planet ^^ EAST AVENUE Rnvaloyai Nnvplfvnoveiiy v,o.Cn south norwalk, conn from its nearest satellite, which is about as far from the surface of Jupiter as the mooti is from the earth. It is uncertain whether the planet is entirely gaseous thruout or h:is matter 110 VOLT A. C. GENERATORS a central core of solid or liquid Its density is only one and one-quarter tb:Lt of water and slightly less than that of the ONLY $5.00! if sun, showing that it is composed largely, Holtzer- Cabot hand gen- not entirely, of matter in a gaseous state. erators, while stock lasts, Jupiter is a world as different from our $5.00. Order today. Diagram II. Orbits of the Four Old Satellites it possible to imagine. There is — own as is Jupiter, and Satellite V, the First to Be Battery chargen, 6 t flamn. of no visible surface crust and there are no Discovered of the New Moons. Satellites VI 110.00: 7 T. U unc. (Uke permanent markings. Different spots on and VII Are Nearly Seven Times More Dis- cut) $27.00: Hydro- Etectric Nearly Four- Generator complete, giving up periods of tant and Satellites VIII and IX the planet's disk give different Satellite to V. Times More Distant Than IV. 2J 3% amp. DC. J25.00. atmospheric phe- teen Immediate ahlpmeot while rotation showing that The Period of Revolution of Satellite V Is atock lasts. Order from thlB ad. nomena are observed. All is constant flux 12 hours and of Satellite IX 3 Years. Scale .5 Cm. = 200,000 Miles. Watson Electric Co., Dept II, Gas Bldo-, Chicago and change. Dense vapors arise from a

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January, 1919 ELECTRICAL EXPERIMENTER 669

NEW SCIENTIFIC WONDER as well as the rapid apparent motion of tile planet thru the sky due to thf revolu- tions of the satellite itself, would be a troublesome task for an astronomer sta- tioned on one of these far distant worlds. You can have bodily vigor. in It would be a common sight to see the success-attaining energ\'

sky at one time the huge planet, the sun attractive healthful beauty ! All '^'^" "PParently see thrM Oluthe?. W,>,Mi, Of\^C \-our5 at practically no cost the great benefits of stone, any object See Bone;' in Fl. ~h. itself, and one, two or three moons. Seen — DwT9 the famous VIOLET RAY TREATMENTS here- A MaKic Tnck Novcltj- given FREE with each X-Ray. from the moons of Jupiter the contellations MARVEL MFG. CO.. Dept. 52. New Haven. Conn. tofore only procurable at big expense from Physi- would appear as they do to us on earth for cians and Beauty Specialists. TREAT VOtJR- such a slight change in position as five hun- SELF at home with $500 REWARD dred million miles, more or less, is trivial I We will pay $600.00 reward to anyont- who when one is measuring the relative dis- lean |)frni:inentlv dim thi- brilliancy of the rajah im. diamond without dealr^-yinn tances of the stars. Observations of the Renulife Violet Ray lltoJ. RAJAH Im. Diamonds stars from the nearest moon of Jupiter Hi© I Thov Ptanii :i!l diamond teete— lire. acid. nd elaae cutting. Their brilliancy la eter- would be attended with difficulties at times, ibI. Guaranteed for a lifetime. Set in eolid HIGH FREQUENCY GENERATOR 30 DAYS' FBEE TRIAL however, since reflected sunlight from a body ;"'i""uTn transforms electricity into the most powerful, real retnm f you can tell it from a diamond nearly twenty degrees in diameter would be .t. Srnd tixiay for oor beautiful. FREE effective, purifying Health and Beauty giving jewelry cataloE in c.lore. Write qow. troublesome, especially the science, niastrated _.„,_,__ lUa„. extremely were agency known to yet gentle, soothing, per- KRAUTH tk REED, 159 N- SUts St.. OcpU 200, CHICAGO. phases of the planet near that of the full fectly safe— no shock nor pain. Eradicates disease moon. Even from the fourth or most dis- You Can Secure a Motor-Cycle TREATS from blood, flesh, bone tant of the major satellites the planet would and nerves; tones and re- at Little Cost Successfully subtend an angle of nearly five degrees. Oc- stores. While relieving by mounting a STEFFET motor on Rheumatism pains and aches and the vuur bicycle. cultations of the stars would be many and NearHis manifest results of disor- They are best made, most reliable frequent as the huge planet globe glides Lumbago ders, it removes the deep and best bill cUmbcr3. We sell you Chest Pains seated cause. Saturates I he complete attachment at a low swiftly thru the heavens. Many a moon- manufacturer's price, or we can sup- Catarrh the system with invigora- ply the finished parts from which you can assemble the light night would appear almost as day Headache ting, life-laden violet rays motor yourself. Instructions and full size blueprints of owing to the presence of the enormous Ear Diseases bringing back normal drawings, 25c. Hardening of Ar- functioning. brilliantly reflecting ball of light and occa- STEFFEY MFG. CO.. 5025 W. Brown St.. Phlla.. Pa. teries sionally two or three moons in addition. Wrinkles Only the brightest stars would be seen Skin Diseases' 110 V. TRANSFORMER Falling Hair Painless under such circumstances. When, however, Etc., Etc. 8 Volts Secondary ONLY $1.00 the small worlds pass into the shadow of ^ reliable transformer for all esperlmental work, ring- the great mother planet and not only the ing beU3. etc. Consumes so little power it will not Electricity move ordinary meter. $1.00, postpaid. Cord and plug, light of the sun but also the reP.ected light 50c extra. Science has modified elec- of Jupiter disappears for many minutes the tricity tliat the weakest Transformer No. 10, giving 8, 12 and 18 volts second- f aJ' ary, with plug. $2.00 postpaid. Order from this ad. stars shine forth in all their glory there may stand its force with- EMPIRE TRANSFORMER CO. out fear or pain. Every as here. In the sky would appear, possibly, tissue Dept. 11 2214 Sedgwick St., CHICAGO and (bre is satur- some of the larger moons feebly shining by ated, patient exp( rienc ing the reflected light of the far distant sun. only a sensation of relief, as if standing in a ray also visible, but beautiful Saturn might be of sunshine. X'iolct Ray B fgam Step Into the Job Venus and ruddy Mars would fail to appear. high frequency has no com- Treatment forgcip parison witli old, crude, »^ arit- I ^e~arr Account Higher Up Thronih Tiny bodies, mere specks of light at this debility, nervousr s electrical batteries and Kim ^^^.. BS& Accountancy etc. 1^ distance, they are lost to view in the glare shockin:? current. Every Free Book, "Stories of Success" of the sun. jar and shock is removed. home-study course fOorshows how thai. A. S. intensive The effcL-ts are marvel- biKKer job and hit' prepared many for the (The next Installment ivill appear in an ously rapid. tuition; easy terms: quick r. International Accountants Society early issue.) ^'^" '-h..„„ . 6€24 So. Michigan Ave. Dept'^"- 39*A Chicago III. Lowest Priced—Most Effective ELECTRIC DEATH TRAPS IN EVERY INVENTOR Violet Ray should have this book. 'TATENTS AND HUN'S RETREAT. PATENT POSSIBILITIES." It is chock For Home Use full of ideas and practical advice, telling (Continued from page 608) what to invent and where to sell. Write Every person would be for your copy today. IT IS FREE. wonderfully benefited by I have requests for patents upon sound to blow the cave to pieces, and which was inventions of all binds. Can you help a few minutes' daily use. supply the demand? connected up with an electric device to the Its astonisliing low price My service ii4 individual, prompt and efficient places it within the reach '14 years experience!. Every expedient is em- time-clock also. Thus did the Boches not ployed to secore patents at least posaible coat. of alt. Write at once for only hope to gas their victims, but to kill H. S. HILL, 804 McUcblu tUt, Washington, D. C. full information regarding them as well, one way or the other. uses, benefits, price, etc. The daily press had considerable to say tamps: in the later months of the war concerning Liberal Trial Plan 50 diflf. Belgium (large bi-color) China. .Jamaica. the many devilish and ingenious delayed Portugal. Venezuela, etc., lOc; 1.000 well mixed, Proves Value 40c: 100 var. U. S., 50c; 1,000 hinges. lOc: A«t3. time-fuse bombs which were left behind in wanted. 50'7f. List free. I buy stamps. L. B. cities northern Inhaling ozone. For Dover, Overland, Mo. many of the towns and of Catirrh. throat and France as the Hun army was being driven lungs. Marvelous lo- ca' results witi gen- toward the Rhine by General Foch's vic- eral toatc elTe t torious armies. One of the simple devices of this nature, which was used to blow up INDEX TO buildings, etc., a considerable length of time after the Huns had retreated from a certain locality, is shown in Fig. 10. It com- ELECTRICAL EXPERIMENTER prised nothing inore than a float tank simi- SCIENCE & INVENTION lar to those used on all modern plumbing for flushing purposes. As soon as it started to rain, such weather being frequent in FOR VOLUME 1, 2, 3, 4, 5 northern France, the tank filled iip and This index contains 24 pages and shows caused the float to rise. When the float every article of interest that has pub- been ball reached its uppermost position it closed lished since the inception of the magazine up to and including April. 1918. an electric circuit, connected by wires running inside the building, to a heavy charge whole mar- It is absolutely indispensible to everybody UniHFT riVCCFRFF ROOKDUUIV telUng the interested in any kind of electrical research of explosive, with results that can be better velous story of the vio- wonderful successes its many uses work. With it everything of importance in imagined than described. These cowardly let Ray. Its — the advancement specified by physicians for rheumatism, neuritis, of electrical science during and dastardly tricks sound quite tame and — the last five years can be readily found. headache, catarrh, wrinkles, blemishes, falling harmless when you read them "Over Here," hair and 100 other bodily ailments but imagine what havoc and untold death and beauty defects, chronic and — acute. Get this valuable book by Price Postpaid they have spread "Over There," where it return mail. 15c. often happened that troops had occupied a RENULIFE ELECTRIC CO. EXPERIMENTER PUBLISHING CO. town for several days before some of these S32 Marquette Bld^. Detroit Book Dept. 231 delayed time fuses functioned at unex- Fulton St., N.Y. ;'Wanteo: Kepresentatives to liemonstrate to pnys.^^fn* pected moments and IndlvtdualB, Fine cooney maltUiK opportuiucy.

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670 ELECTRICAL EXPERIMENTER January. 1919 EXPERIMENTAL STOP SNUFFLING! MECHANICS. Experiment 108. In 1895, Roentgen while Sneezing, hawking, spitting ^(Continued from page 638) working with cathode rays found that and coughing. WUy do you secured to the saddle. The circle should be a photographic catarrh anyway ? You hare marked with were not bom with catarrh a sharp scriber where the you contracted it. This of- boring is to be done, also its final diameter. - fensive, unwholesome, d I 3 a By bringing the work forward to the sharp greeable complaint fastened it- -sL point of the scriber which is attached to self upon you and grew. Nature is trying to prevent more serious the boring rod, and slowly revolving said consequences due to the conges- boring rod, the scriber making the proper your body, finds an out- lion in mark, this will aid in boring the hole to the let for the accumulat«d waste, by way of catarrh. You cannot proper diameter. At the same time you can get rid of it the way you are see whether the work is secured to the snufflng going—sprays, lotions, saddle with respect to the central line of powders, drugs and medicines won't stop it. You know catarrh the cutting tool, also live and dead centers. leads to other troubles—serious The cutting tool is held on block T. H., or ones — throat, lungs, stomach. tool holder, and is secured to the boring Intestines—all become affected. Brijs/7 c/zsc/iarge You can never enjoy good health rod by a set screw. The boring rod is run F:a 95-1 If you have catarrh ; you won't between the centers and firmly attached be efficient In anything as long to the live spindle by means of a lathe dog A Brush Discharge Is Composed of Many have catarrh, and It as you Fine Sparks, Forming an Effluve. detracts from your personality D to the face plate. to be hawking and BnuflUng The novice can construct a very simple plate which he happened to have near the around others. form of boring cutter, such as that shown cathode ray tube blackened on development, Str«nfTen Build Yourself Up in Fig. 4 This consists of the usual boring just as if it had been exposed to light. On Th< PirlMt Haa Be Clean—\V h o 1 e s o m e rod, B. R., which may be of any desired investigating, he found that a radiation out- Healtliy—Virile. Go at It the right way. Na- length, depending on the character of the side the tube always accompanies the pro- ture's way : no drugs, no medicines, and you work. rod should tool banish caurrh from your system. Let me show The be made of duction of cathode rays. These radiations you how, by ray method of health building, body steel, heav>' enough to prevent its springing diflfer in many ways from cathode rays and developing called or bending when used in boring. The are called Roentgen (or Rontgen) rays STRONGFORTISM longer the rod, the greater the chance of after their discoverer, also X-rays, the name lu practice neror falls—U bnllda new tlnu«. flvei springing. It is therefore advisable to make given to them by their discoverer. These brawn aod muscle. It Inviaorates b9*n acUoa. •tren^th- cns Udners. and makea tha t>o>weU more bj thalr own the rod as short as possible. A one-half rays result from the sudden stopping of your body naniral strenfrth. U makes etery organ In inch hole is made in the center of the pulsate to health. Cnder this kind of influenoe. catarrh the cathode ray. The kinetic energy of the qolta for good, ao wUl coosUpation, Indigestion, n«r- boring rod, which is used to secure the cut- cathode ray when suddenly stopt by en- Tonanns. palpltaUoo, rupture. rheomailAm, weak hurt, poor monory, physical weakness. rltaJ looses, short ting tool. This is about the size cutting countering an obstruction produces an elec- and disorder*. wind, and all sorta and kinds of ailment* tool that the novice will need in his work. tromagnetic disturbance which travels out- If you are loo stout or too thin, flat cheated, op round shouldered—Sironirfunlsm wtU alter it. It will Another hole is drilled at right angles to ward from the suddenly arrested particle. vigor and Tirlllty and nerrooa make you grow In — this one with a one-quarter inch drill and energy— It will restore your Tlullty and keep your foroes Tltal. No matter what your condition la now, or what tapt for No. 18-5/16 inch thread. A head- hablta you contracted or Indulged Id— I will ahow that yon can renew ydurself. Yon want to be strong, less set screw is threaded in, a saw cut healthy—a rtrile man—you want to be all that a man being made on the outer end in order that ought to be and I can and will show you how to make yourself the man that la desirable from every stand- it may be screwed in with a screw driver. point. tool Tell oe your sllment and send three 2-ceni stamps The cutting should be made of the to eoTflf mailing expenses, and I will send you my highest grade, self-hardening tool steel. Its book. "PBOMOTIOV AXD CONSERVATION OF HKAiyrH. STRENGTH AND MENTAL HNmOT." length should not exceed one-half inch, the written for vnur interest and woifarn. diameter of the boring rod. The cutting LIONEL STRONGFORT side of the tool is ground as indicated in Phyilcil anil Health SiMclalIrt Fig. its slightly 73S Pirk Bldg. Newark, N. J. 4, bottom edge being rounded, so that it will be prevented from chipping or breaking. In boring a hole in cast iron, it will be A Simple Spark Discharge from an Induction start Skinderviken found advisable to with a heavy cut. Coll. This is done so that the sand or other silica The velocity Transmitter particles that may have adhered to the cast of the X-ray is found to be the iron when taken from the mould are imme- same as that of light. For the production Button diately removed. of concentrated X-rays, a special form (the focus tube) of cathode is Njthlng like it on ihe market. In the forthcoming issue the subject of ray tube Will msks an old transmitter bet- used (see Fig. 97a). Cathode rays coming ter than new. AdJoited In s llCfy. "Taper Cutting" will be considered. st all angles. from the SupenenslliTe. Talks {To be continued) concave spherical surface c con- See our ad In the December or verge and strike platinum plate •oming February number for Innumerable uses to P, where which it can be put. X-rays are generated which radiate in a Priea $1.00 each. Dlscnunt In Quantltlea. Madrid gets its electricity for lighting hemisphere as illustrated in diagram. Bend ut OfM Dollar, for vhich tre will mail ene and power from a hydro-electric plant 120 b*tUm prepaid under our money-bofk ffuarontet. By moving a zinc sulfid screen around miles from the city. Booklet No* J free for the aaking the tube, we find that the X-rays cause fluorescence. If the hand or Skfajderviken Telephone Equipment Co. A company in Japan has begun the pro- some other object is placed on a photographic plate K'"-r v.--'.)" r.T'Tenle'-ic !n writing us, sddrsjt duction of soda by an electrical process. STECO 2134 Clark St.. Chicago. III. and X-rays are allowed to strike the plate, Electrically operated cash carriers for a short exposure will give an X-ray photograph (see Fig. 97b), because of the ability DO YOU WANT A stores have been invented, the motors of which are supplied with current thru the of X-rays to penetrate many substarKes Wonderful Muscular light. This wires on which they run. opaque to makes possible the Development, photographing of interior parts of the «rth perfect health, abundaase human body for diagnosis. X-rays are sim- vitality and great strenfth? of EXPERIMENTAL PHYSICS. in they cannot re- You can get all tlie above. ilar to cathode rays that he If you want Lhem. and I can (Continued from page 626) show you bow. The resnlta of my ystam are shown on my sisted of negatively charged particles, re- own peraon. and that la reo- ommendatlon enough. membering that an electric current is an I hare prepared a bvoklet. electric charge in motion, and that an elec- llla^trarM witb photographa of myself, which will tell yon tric current tends to move in an electric how ycru can obtain a devel- field in the three-finger npment the same aa I did. a direction given by The name of It Is motor rule (see Lesson 16). Hence, our "Muscular D«vtl«ffnsit" GET IT— It wUl IntersA and present belief that the cathode rays are BARI.F, E. LIEDERMAN benefit yon. A oopy of thll U- negatively charged electrons. The fact that Wbj not look as healthy itruotlve and UlnatratM b«ok- and b« aa strong as I am f let will be sent you apon re- these rays give a negative charge to bodies ceipt of lOo—stamps sr ooln. on which they fall doubly strengthens the tARLE UEDBRMAN.De^ 204.203 BreadwtT.NawTarkdly theory. The deflectibility of the cathode rays in magnetic and electric fields fur- Flg. 95-B. The Cathode Is Concave and T YPEWR ITERS nishes us with the necessary data for com- Spherical. The Anode Consists of a Small ALL MAKES. SAVE |39 TO W> puting the size, weight, and speed of the Piece of Very Thin Platinum. The Cathode on rebuilt by the well-known "Young Pn>eess." Are Converged, Focus on the Platinum electron. The size and weight is extremely Rays J*old for low caih-lnsUllDient or rented. and Are Therefore very Concentrated. The Rental applies on purchase price. Write for small, the speed tremendously large (about Incandesces. Thus Showing the full detslli and guarantee. Free trial Platinum YouRB Typewriter C*.. Dept 659. Chlcaoe 100.000 miles per second). "Heating Effect" of the Cathode Rays.

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January, 1919 ELECTRICAL EXPERIMENTER 671 fleeted or refracted as light can, but they the four and one-half inch or secondary are diflFerent in many important respects. coil, from three-eighths inch wood (white X-rays penetrate many substances which pine may be used, as it is quite soft and cathode rays cannot (X-rays pass right easy to handle). When thus cut they are thru glass, whereas the cathode rays do placed on top of each other and two one- not). X-rays cannot be deflected by elec- eighth inch holes drilled about one and tric or magnetic fields and hence cannot, one-half inches apart and toward one end. like cathode rays, consist of electrically They must, of course, be in ahgnment, as charged particles. The real nature of they are for the slider rods. The center X-rays is still unknown. Lead seems to be must also be free as in one of the four and the most difficult substance for X-rays to one-half inch covers fifteen holes are to penetrate. Hence, lead is used as a screen be drilled for the fifteen secondary taps. to shield objects from X-ray action. Care The respective taps of the secondary are The Electric Safety razor makes shaving a ^hould be taken in experimenting with drawn thru in order and the ends nailed pleasure. Blade vibrating 7,200 times a minute cuts the beard smoothly and without slightest X-rays as their penetrating power results to the coil with brass nails. Care must be puU or Irritation—feels like a gentle massage. IP. serious flesh bums under either pro- taken to get the openings for the sliders Can be used with or without electric current. •racted or oft repeated exposure to theiH. directly under each other. The completed All users of He Lck-TrO-ShaV sjeak *elUf it. (To be continued) secondary is shown at Fig. 4, and also the — sliders and their arrangement. The sliders A barber says "Have Bbaved for yeara and have nerer used any shaving device near lt8 equal. THE MANUFACTURE OF VACUlfM are made from No. 8 copper wire which is A borne user says— "The most pleasing shave I've ever in life. Shavea my face closer than 1 stretched taut the bad my DETECTORS. by screws at top of the used to shave, hut there is no aftei irritation or 111 (Continued from page 630) cabinet. A screw eye is inserted into the effects ai I usually get from another razor." No. I Made for use from Light Socltet. than the filament when the tube is jarred. top for varying the coupling, as will be No. 2 Made for use from Dry Battery. Write illustrated circular descritilng Lek-Tro- adjustment on the plate and grid described presently, and the primary is for After Shav Safety Bazor fully. aas been made, the assembly is inserted into screwed in place (see Fig. 4). VIBRATING ELECTRIC RAZOR CO die prepared tubes and the end seals made. Dept. 122. Omaha, Nebr. K snort length of small diameter tubing is THE CABINET attached to the seal at one end of the tube, Very little need be said about the material this being for connection to the pump mani- for the cabinet, perhaps, as the building of fold. The tube is then carefully annealed this depends entirely upon the ways and ind is ready for exhaustion. WIRELESS means of the Amateur, so only the meas- A number of tubes are sealed on the OPERATORS WANTED urements will be given. The cabinet is manifold in the oven and the temperature If you are ambitious and wish to better made like a box except that the top and is gradually increased to 900 degrees yourself this is your opportunity. back are not put into place until the ap- Fahrenheit (480° C.) at which point the America's new Merchant Marine needs paratus is mounted. The front panel is pumps are started. The tubes are heated in trained wireless operators. Good pay and one-half inch thick, twenty-six inches high splendid chance to see the world and help this manner before the pumps are started and eight and one-half inches wide inch in the reconstruction of Europe. Our so that the air contained in the tubes may (% classes have supplied hundreds of expert Bakelite makes an excellent job) the sides conduct the heat to the central elements ; Wireless and Land Line Operators. are six inches wide. Write for illustrated booklet giving full and drive off the occluded gases (i.e., gases Particulars. "The Best Radio School in held in the molecular interstices of the SWITCHES, SWITCHPOINTS AND METHOD lew York City." wing, filament and grid structure). When OF VARYING THE COUPLING Y. M. C. A. the pumps have produced a vacuum of one sviritches 86th St. and Lexington Ave. the temperature of the tubes is The were made at a cost of eight ^B^anch' micron, York very gradually increased to 1000 degrees cents each, using also such odds and ends Lenox 60SI New (540" C). At this point they must be as are found in any laboratory. The knobs watched very closely as the melting point of this glass varies greatly and should the walls of the tubes become soft, the vacuum would cause collapse. From one micron, Learn Mechanical Drawing the vacuum slowly increases, and after ibout five hours of continuous pumping the Thousands of Draftsmen tubes are sealed off at the manifold and allowed to cool in the oven. Wanted — Salaries McLeod gages are used in the measure- $35-$100 Per ment of vacua but I have foimd that a much more accurate vacuum comparison Week :an b« made using a large induction coil. For this purpose an electrode is sealed to the manifold or at some point in the vacuum line. One terminal of the coil is connected to this electrode and the other coil terminal is connected to the low vacuum pimip. A calibrated spark gap is used on the coil and when the vacua is high enough and the residual gases are properly pumped from you earning more ABBthan the average the tube a spark will jump the gap imthout man J If not, my you. 1 offer ymi tue J glow in the line offer win hiterest vacuum or tubes. The service that my school affords, l best me- Tacuum used in the tubular detector will offer you my personal histruotlon in chanical drawing. 1 offer to leach you permit a five inch (12.5 cm.) spark be- expert draftsmansiilp in your own home. the high-paying tween needle points in air. I offer to lit you for position of draftsman In one of tfie Prof. Richsirdson has shown that when United States govenunent departments or one of the great machine shops of new metals are heated to incandescence offer to do aU this at a reasonable America. I Qme. expense to you. and in a comparatively short they emit positive ions, probably because of was. The drafting field is not crowded. It never inaie the impurities or gases in the metal. I It probably never will he. You cannot taking draftemanshlp. I do Dnot CUFLIN, President have found that this positive mistake by up ^H ROY C. ^k discharge know of any single profession open to men t«a»y aaldL SCHOOL OF eliminated wlilch offers better opportaoiUes. Aa I have wU COLUMBIA must be to obtain maximum earn™" ^f ^^ the beglimlng of this article, drattaman are M DRAFTING sensitiveness of the tubular detector, and ing »S6 to $100 per week. complete, , iny„„""" There is a demand lor men who drawing Inttrument* Eaeh of our ttudontt It this is accomplisht during the manufactur- enough. Many or FrM — course. I cannot supply graduates fast presented the beginning with a of profeatlooal course. at Ht ing stage by burning the filament on alter- them are Uken even before they complete their drawing Instruments. lh»t Thla unusual demand is eiplalned by the tact my en- A. Taluable book ecmt without ohaxge Merely flU nating current for about two hours. Tubes studenta enter on actual drawing work the day they — the coupon below for a faluable book on drawing. roU with me. They spend no time with preparaUon and In that have not been treated in this manner and complete Information In regard to our course. are found to be less sensitive than those "^ra OF°Tin! FINEST AND BEST EQOIPPTO^IN- IN AMERICA TEACHES TOD iOCHAN- in which the positive ionization STITCTI0N8 COLUMBIA SCHOOL OF DRAFTING has been ICAL DRAW I.NG AT YOnB HOME. destroyed. With the ending of the war. the day of big opportunJ- Dept. 968. Uth and T Sts.. N.W.. Washington. D. C thij true hi tles for trahied men is here. Espedaiiy ll Without obllgatloD to me. please send me your lUtU- A VERTICAL CABINET TYPE the case of draftsmen, on whom the mechanical industrlea trated book on Drafting and t«ll ho>w 1 may secure does the re- COUPLER. of America depend. On no one profession your complete Home Study Courae, the DBAWXNO construction of Europe so nearly center. OUTFIT FREB, and your help in iecurlng s posi- (Continued from page 631) tion as Draftsman. ENDS Columbia School of Drafting Name FOR THE COILS Pre*. ROY C. CLAFLIN, Address It is necessary now to cut a base end to 14th Sts.. N.W., WashlngtoD, D. C. Dept. 968. & T City BUt« fit the five inch primary coil and two for

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 672 ELECTRICAL EXPERIMENTER January, 1919

were purchased from a hardware store. rods ; finally put on back. The diagram of These are glass drawer knobs and have a the assembled coil is shown in Fig. 7. brass shell into which the glass knob is There are many advantages of this type

cemented ; also a screw is fitted into the cabinet, as it is both compact, inexpensive end. Five of these are needed. The switch and neat. It does not allow dust to settle bla'de is cut from a piece of spring},- brass between the windings and prevents the or nickel. Cut two pieces three inches long entrance of other foreign matter. One and taper down one end (see Fig. 5). The complete turn of the coupling knob will other end must be made to fit the knob. A change the coupling completely. Accurate hole is drilled into this end and the blade tuning of the primary is worked out to a is soldered to the brass cup; bend the con- very tine extent and the novel arrangement tact end as shown. Also cut two pieces one of the secondary tuning will be seen to and one-half inches long for the secondary have many merits, as any portion of the switches and fasten in the same way and coil may be us«d and the direction of cur- to fifth knob solder the hand a clock. rent also the "CHEMCRATT" for the of may be reversed. Often GET Christmas I Perform all kinds of wonderful chemi- The switch points are common uphol- coupling will not have to be changed in cal experiments and tricks that will sterer's nails with the brass tops and small order to vary the secondary, as both amase and puzzle your friends. Learn the washers to fit the under side. After the switches may be moved and so bring an- principles of Chemistry and have real fun wire has been drawn thru a hole drilled other portion of the coil into play. at the same time. Get your outfit now I in the cabinet for it, it is twisted around With a galena detector stand and using Chencraft No. I —tl.25 W«t of Mississippi BlTer and in Canada—$1.50 the nail and the loop thus formed pushed a "radiocite" crystal, this outfit cannot be Chomcnirt No. 2—$2.50 far down into the hollow of the cup of beaten and other stations were brought in West of Mljslsslppi River and In Canada—$3.00 ihe nail. small amount of flux and a that never were heard before. This Chemoraft No. 3—$5.00 A may West of Mississippi River and Id Canada—$8.00 piece of solder about une-tjuarter the size have been due to the excellency of the Bo rare srou eet ••CHEMCBAFT," the original of a split pea is and moot complete and sclentlflc chemical outfit. the cup Ask for It by name at your Toy Store, or send placed into price and we wlU deliver direct prepaid. which is held hol- ffooA-up for Primary and secondary low upward. A hot

\ Todst Apnones The Porter Chemical Company iron is now touch- \ the nail, Industrial BIdg.. W. Washington St. ed to and Hagerstown Maryland the solder will melt flush and make an excellent connection. The washer is now slipt 35 MILES PER HOUR over the nail and Built by a boy from Junior parts fxir- the nail driven in nisbed by us. Any boy can build this car. Pans xery cheap. Send 2S place. The wash- I'fiirs for hlue prints and price list of parts showing how to build ttaJka ers are not essen- sicedy little car. tial but make the heads of the switch point protrude •mary 'êcondorg more. (Fig. 5.) Fig 6 The method of varying the coup- Hook-Up of Primary and Secondary Windings On Vertical Coupler. Note That Secondary Switching Circuit Permits of Reversing ling is by a cable tha Polarity of the Circuit. and drum arrangement. Rack and pinion methods need accurate workmanship crystal, but the coil has something to do for them to operate correctly, so this novel with it, in my estimation. home-made method was devised, .\fter the clock hand has been soldered to No. 5 knob, a twenty-four inch (circumference) wooden SOLAR ENGINE USES SUN'S wheel is fastened to the screw of this knob. ENERGY. Violin, Hawaiian Guitar This wheel is locked in place and a Ukulele, Oaitar, Mandolin, Cornet or Banjo bearing is made to fit the other end of the {Continued from page 607) Wonderful new fystem of t«achlog unte minic by niaU. To AmI screw, so that there will be a fairly good papilj la e»ch loralily. w«'U give a l.'osiiiKTb Violin. Mandolin, rkulel^.Goitftr. HawMi»aOaitikr. C'.riiot or banjo alwolutoly free. axle and bearings formed, one bearing being Messrs. Shuman, Boys, and Ackerman, TeryamAll cturKe f'^r Jr-iv^nsoDlyezp^^nsA. We guaranU-oHuccost the front panel. bent piece of brass will engineered and built a large solar energy orDOcli&ree. Oimi.Iclcouifitfroe. Writo at '^"ce—no obligation. A plant at StlRBEftUND SCHOOL OF MUSiC. Ofot 422. CHICAGO, ILL answer for the other end. A piece of Meadi on the Nile, Egypt. This leather is fastened in such a way as to cause plant developed 100 h.p. The total area of friction against the wooden wheel. A piece Funshine collected was 13,269 square feet. of cord is nailed to the wheel and wound The maximum pounds of steam generated 12 z around the groove ; the cord passing over a was pounds per 100 square feet of sun- small pulley and secured to the screw-eye shine, or the equivalent, to i8s square feet Tatente-J ' Sept. 3, 1918 on the upper end of the secondary (see per brake horsepower. The best hour's run B0T5 I We hive ttxe'ntA scores of lellen Dke Ibu W. A. ROTHWELL. M.O.. Kendrlck. Idaho Fig. 4). developed, at atmospheric pressure, 1,442 Automatic Rubber Co., Columbia. S. C. ASSEMBLY pounds of steam. Hence (allowing 22 Gentlemen: Ertcloied And personal cheek for SI. Kindly oblige me by forwarding two Zip- Along the mid-line of the panel and four pounds steam per brake horsepower) the the 2Id»; last I ordered were perfect In every and eight inches up from the bottom, maximum output for way. Yourt sincerely. W. A. Rothwell, M.D. re- an hour was 55.5 The dofôr sav^ thoT arp O. K.. b^vs, Ord'^r from n» or CA- spectively, drill two holes to fit the screws horsepower (about ten times better than your Siurtii.e ''^ (ju-Ws Store. ZIp-ZIp complete only of the switches. Above each of these drill any previous results). This means 63 brake AUTOMATIC RUBBER CO., COLUMBIA, S. C. two smaller holes for wires which will go horsepower per acre of land occupied by the to antenna and ground. Draw the flexible plant. Moreover, no marked reduction in wires thru; solder to switch blade (Fig. S) the horsepower produced was noticeable in and put switch in place. Place a spring the early hours of the morning in TELEGRAPH on or the PIQURES the under side of switch to keep it tight. lale hours of the afternoon. Thij pict ure of WUjo n re- Describe an arc with each switch and using The temperature of the sun, as afore- fnveti over Leiskman Picture about two-thirds of a complete circle for mentioned, has been calculated TeUtrphint Maehims. to be about Will the transmit pietures, maps, arrangement of switch points, divide 6,000 degrees centigrade. Several authori- drawings and kandwriting. them equally into the area thus allowed. ties point out that this terrific heat there- Smd for deicriptiee folder. Drill holes for the wires of the switch fore precludes any possibility of the sun L. J. Leiahman, Dept. T points, solder to switch points as already being a molten mass in the process of com- OKden, Utah described and hammer into place. Then bustion. It has been thought recently by seventeen inches from the bottom and two many to be a great mass of matter possess- inches from the mid-line each way, drill ing to a remarkable degree radio-activity holes for the switches of the secondary. akin to radium. Helmholtz proposed that SônAVUTION Mount the sixteen switch points in place the sun could keep on producing energy at Learn of the great opportimitiea in this ^.tw as per diagram for connections. its present rate by accounting for il ,000.000.000 Indtlatry. Thooaaoda of men needed. same on Learn brnall—free book talla how. Write at ooee. Put the top on the cabinet with the bolts the basis of a slight annual shrinkage in its annuL aEM mmiiTi, Det< 744|M niiitni..e>ic»n (eve-bolts) for slider rods and tighten the size. From observations and measurements i ou brnriii by mentioning Vif "Electrical Experimenter" when writing to advertisers. January. 1919 ELECTRICAL EXPERIMENTER 673

of this heavenly body made from year to potential of one sign seeking its affinity or year it has been computed that the age of opposite potential sign, in order that it may Big Money for Boys! the sun would, on the shrinkage basis, be neutralize. Following the path of the ball 17,000,000 years. it comes in at the base of the ribbon dis- The radiant energy received from the sim charge at the left, whence it travels straight across, almost parallel to the wires in the at the outer surface of the earth's atmos- \ h background, then it comes to rest in the phere is equivalent to 7.S00 horsepower per acre. Of this about 70 per cent, or, roughly upper right hand corner. It now slowly follows speaking, 5,000 horsepower per acre, is an irregular path with a few stops transmitted thru the atmosphere to the land and makes its exit into the heavens, no surface proper of the earth, at noon on a doubt to join its patiently waiting other clear day. Lesser amounts, of course, are half. received in the early morning and late after- Photo No. 2 (lower center) is a 3 minute noon, owing to the greater thickness thru exposure, during which time the camera which the energy must pass. was moved once but very slightly, as you see the double Relative to the basis upon which solar from print of the chimneys in the Learn r~^ , background. In this picture will y,, energy is calculated for the earth's surface, be seen innumerable paths of the light ball this is generally made, it may be said, on where it has traveled at various speeds. the "solar constant," as it is termed, ascer- ELECrSitlTY tained from 696 tests conducted by the L. E. Church, Bailesville, Okla. in Smithsonian Institute of Washington, There is a wonderful opportunily right now various parts of the world, which resulted for boys who like electricity. Thousands of in accepting 1.93 calories per square centi- men from the electrical industry have gone into meter per minute, equal to 7.12 British ther- EXPERIMENTS IN RADIO- the service and others are going every day. mal units per square foot per minute. This ACTIVITY. Boys who are ambitious and will train them- is an average value, all things considered. selves in spare time can ste-^ into good positions Only about three-fifths of the solar radia- {Continued from page 636) and play a real part in winning the war by tion produce any impression on the earth, carrying on their work. Good salaries are and it is only the radiant energy which falls radio-active study. It is thought unneces- offered with rapid promotion. on some material body that is converted sary here to give further experiments in For 27 years the International Correspond- into heat. The best body for this conver- this phase of the subject as they will sug- ence Schools have been training boys for suc- sion having been ascertained to be a dead gest themselves to the reader. It is an in- cess in electricity and over 200 other subjects. black one. tensely interesting subject and the reader They will help you prepare right at home for will derive both beneficial knowledge and a position in the line of electrical work you like pleasure from his experiments. There are best —or in any other work rhat appeals to you. many other properties of these substances "ODD PHOTO" CONTEST. Thousands of boys, through I. C. S. training, besides their ionizing power which will be have stepped into fine jobs, but never were taken up in later articles. {Continued from page 616) opportunities so great as now. {To be continued) as to work the strings. Fourtlily, it was- Let the I. C. S. help^o?/. Choose the work you like indoors on a cloudy day. I simply guest at best in the coupon below, then mark and mail it today. the time—about 25 seconds for each expo- This doesn't obligate you in the least, and it will brio^ you information that may start you on a successful sure (double exposure) and let 'er go at career. This is your chance. Don't let it slip by. that. The streaks are the strings ; the BUILDING A 3-INCH SPARK Mark and mail this coupon nottt. lenses were between the two strings. I did- STATIC MACHINE. ^^ —™-" ^.^ —•— ^— TEAR OUT MERE — —— — —.— n't expect it to be any good at all. So if INTERNATIONAL CORRESPONDENCE SCHOOLS you have any extra dollars flying around, {Continued send one out to Iowa. Fred Wagner, from page 633) BOX 6172, SCRANTON, PA. Burlington, Iowa. Explain, without obligating me, ho'w I can qualify fur tha position, or in tlie subjecl, belore which I mark X. should reach the comb and thus prevent the escape of the U KLI-XTItlOAI. ENtilXFF.It nCnEMICAr F.NCINEER electricity before it reaches 3 Electrician D SALESMANSHIP the metal points. Zj Electric Wiring D ADVERTISING MAN 3 Electric Lighting Windo^v Trimmer NOVEL PHOTO OF CITY AND An iron ring placed on the conductor Electric Car Running C Show Card Writer Heavy Electric Traction C Outdoor Sign Painter LIGHTNING AT NIGHT. heightens its capacity. This consists of an Electrical Draftsman C RAILROADER iron wire bent in a circle Kleeti-K' Maclilne llt-signei- C ILLUSTRATOR and then well Telegraph Expert G DESIGNER The photo I submit is a picture of a city insulated with paper, which is later var- Practical Telephony n BOOKKEEPER at nii;ht, taken from a high mountain near- HEOIIAMCAl, F.Ni;i\F.F.R C Sleiioprnplier and Typist nished with shellac. Mechanical Draftsman C Cert Pub. Accountant by. The object of taking the picture was 3 Ship Draftsman ^ Traffic Management If the handle of the machine is turned Machine Shop Practice Commercial Law to "snap" the lightning. Z} towards the combs, electric sparks can be Zl Toolmaker GOOD ENGLISH Z! CJas Engineer S1'«TI0NAKV EMJINEER Rob't Sullivan, Canon City, Colo. drawn from the small ball attached to the 2 CIVIL ENGINEER CIVIL SERVICE Mapping Railway Mail Clerk end of the brass wire holding the comb. Ij Surveving and D MI.\E FdUFWN OREMJ'K Z] Tpillle OTer8P4>r or Snpt. ARCHITECT AflRKirLTlIKE It is tinnecessary to explain the uses D of Z2 .irfliilectnral Draftsman _ Navigator ID Spanish Leyden jars and other apparatus which can D I'MIMBIM) ANI> HEATI^tl Z] I'oiillryllaislne IQ ^re^ch AT LAST—A PHOTO OF "BALL D Sheet Metal Worker J AntumohileH l^ ItalUo LIGHTNING." be used in connection with this machine, as any "Physics book," under the heading of "Electricity," describes a number of them. Speaking of "Odd Photos" or something Present for the "bug" to worry about, I think I Occupation_ have it here, in the form of two actual Street and No photographs, either of which contain any kind of lightning one would i.e., want, THE Citv_ chain, ribbon or ball. CITY OF SPLENDID NIGHT. YOU CAN MAKE BIG PROFITS These photos were taken about six {Continued from page 623) WITH HB BATTERY CHARGEF months ago (Pardon the selfishness) on Others are matdos $100 to $150 a moctl extra profit. So can you. No eii)erlenc' the same night and about five minutes apart, footed torch-bearers led the way. None of necessary. Write for full particular* o- during a very damaging electrical disturb- send $15 with this ad. to put this them, proud souls, ever saw their doorways money - making HB 500 w a t ance in this locality. Charger In your garage on tria' in fullest beauty, the beauty that is electric, order. Balance in 9 monthly ray I may be in wrong my conception of the that softens rude prominences while it ments of $20 each. No risk. Abso- lute money-back guarantee. Delay impression on the right side of photo No. 1 throws a lustrous, enchanting glow over means lost profls. Order today. (the upper left photo) being ball lightning, fine design and decoration. Hobar t Brog. Co. Box IE, Troy, Ohio but would suppose it to be such. This pic- The "City of Splendid Night" forever ELECTRICAL ENGINEERING ture is an exposure of 30 seconds. There Bliss calls me to fresh delights. I go the way of Condensed Course— Complete In One Year. was no artificial light of any kind in front rinotriofll golnd. sclentiflc. practical—withoiit fJuTl! a side street at the beckon of a light and, kiCI/LI It/dl I'or young men of energy of the and character. camera. This phenomenon was not _ , 26Ui year opens September anon, find myself before the stately pile of , 25th. Write perceptible to the eye—or at least was not *""""NCnOOl" f*^'' ""^w catalogue. a church, mirrored against the sky by the 260 Takoma Avenue, Waa hlngtoii. 0. C. observed. guardian pillar of radiance that stands be- If this be ball lightning we then know fore it. Later I come upon a green park that ball lightning is S?oToN AVIATION of an oscillating or bordered with electric jewels. Here I seat Learn of the trreat opportunities this pulsating nature, as is in new evident from the myself and watch the trees play tag with SI ,000.000,000 industry. Thousands of men needed path taken by the ball. Pn^ssibly this is a beams of electric brilliance. Learn bymail— free boolj tells bow.Writeatonce. MTIOHAL KM IHSTITUTE, Oepl7141 Manonaido.Cbicaie You benefit by mentioning the ''Electrical Experimenter' when writing to adverti; ; ! .

674 ELECTRICAL EXPERIMENTER January, 1919

You may know the white lights of the back and base. All waiting in thrilling ex- night, so do I, but I also know where are pectancy their turns to dance and frolic in ^n/'nK Chiropractic to be found those more precious sights of the silvery glow. The scene will surely the city, made possible by night and elec- enchant you. Earth-weight passes, the OB eanly Ati4 qoicklj trt yoor I»*ciar'* ittr— Yoo tricity. And so I wander lovingly thru the senses are ethereally acute, you feel the laa (mmIm Unirrmry DipJaoiA Irwtt U>f well-known rdocatioiul iomrunoa. CMcai* ValvvnUr •! AM«rlcaa "City of Splendid Night," and visit its pulse of Beauty, and the heart within you iclwtrtn and enter modem profrmtoa par>RC oihen t£i,000anH more a year, tiraptr by tikinr out shimmering shrines. takes iire. rje PKRSOSAL SERVICE INSTRL'CTIONS in (HllorR.ir-Tir durinr spare 'ime •! h»»«- O"" So lives the radiant poetry of Central etJjrje I'Srml t.» a lrri'!» omnizcd n-booi th»I The Park at Night Park. It is there for all of you who will Gctrantrts S*tiaf»ctioi or Refoiida Money go with vision for its picturing. It is the klv mdenti lodif have U< inrome*. Tliuus»nd» next you walk abroad at night, XIti nrfici. Let Qi help YO J. great gallery exhibiting bc-Iprd lo foccTM WHEN the Light of Man- voloiBC •^^'^S^ Wnir ti'f pr*«t and ir«"'al offel of a \Z choose Central Park, and preferably hattan, ^^^î;5^ RcffrriKf l.ihno FREE loi a lew daya. Stilt* that part of it which ranges south L 1>r. D^ WO. IT N. Stats. E l CMcaco. THE MIDGET SLIDE RULE of Seventieth Street. Enter to the left of New York in the Rain. will adil. subtract, multiply, di- General Sherman and follow the friendly vide; scire problems inroMns even bypath that skirts and uneven roots and powers. Vls(i the Japanese Lake, where out the stars. Draw a leaden gires tLe logarithms of iPimbers BLOT the swan boats ride at anchor. I call it the and Che Sines and Cosines. Tan- mantle of cloud across the hea\ens. fenis and Cotancents of all angles. "Japanese Lake" because the first sight of Let the skies open every pore, until IS operation Is Ter>- elmpte: qulck- it, thru certain trees bent and burdened Ly soK€3 any matiiemadcal prob- earth rejects the surfeiting torrents. Fields lem. Durably made of met&L with weird charm, suggests a Japanese are sodden, woods sullen, villages sordid, Adapted for ahop and office use. print, wherein Fits the pocket. 3^ Inches diam- the towering Plaza becomes and all the open country a sticky mass of eter. Price with Instructions. Jl.OO Fujiyama. The while you stand the lake T»Dr B)on»r bai^k ll you u-* not antlirfttd morbid moisture. Gilscn Slidr Rulf Cc. Nilr* Mic^ gathers lustre from many sources, taking But old New Amsterdam is glorious toll of light until its tiny, radiant body fare seems a great, luminous tear, dropt from So you forth and witness the won- the eye of God. ders of this city of cities in the rain. The Ferfeclt-d Gasoline Engrnes- perfect time is during the first silent ' hours ^. 1 a,Dd 1"^ h. p.—fyr Farm You can't know Central Park until you axid Shop use. Price $27.60 of the morning. Then you may surprise it and up. Also see it at night, and then it is no more the WASHING MACHINES in the full splendor of its bath. The build- park than the city surrounding it that We ship on trial. Send for ings stand stark, dripping, and in great Booklet and Special Offer. thralls you. Each season has its own par- SIEVERKROPP ENGINE CO. masses rise triumphant thru the drenching. 1401— 19th St Raolne. WU. ticular charms; but it is best to consult your almanac prior to making the excursion, for The gutters are long panels of flowing STARTER for FORD CARS mirrors which break into no moon is wanted at such a time. The and shatter ten million fractions lights of Manhattan should not be dis- in reflections, where turbed, or marred, and a cloudy night, tho treacherous corner grills suck them into roaring depths. About each light that MUSIC TAUGHT FREE with rain yet a long way ofT, is to be especially desired. punctuates the avenues and streets there is a hazy glow. Here sparkle the jewels » _o In truth some of the rarest charms of Ifoi aûiJU^m thrown overboard by the clouds in an effort îzti I con MtiA iTuuuA. i^t this great enclosure are the vantage points In Your Home. Write today for our booklet. It tells to lighten their ballast. bow to learn to play Piano. Orffan, Violin. Mandolin, it offers for viewing the glowing city. From Itnri)a. tho hoisting Goitar. etc. Revmêrs or advanced pupils. each hill and hollow and rustic bridge you As themselves on the liquid '' American School of -z 57 lakeside BIdg., Chicar^ see sights that make you feel Nature has ladder of the storm, the ascending mingled lights of the city burnish prepared a wonderful gallery in which you the grey vault may stand and see the thousand pictures above with golden copper, as the hearth- painted by Night and Electricity. flames picture themselves in the kettle PHONOGRAPH swinging froin 'he crane. PARTS FORANY STTLB MACHINE And the wonder of the lighting. Never The romance of Masonry and Electricity Your Build your own cabineCa have pictures been hung for exhibition with We show you how more rare understanding of the art of is before you. It is a drama done in pour- Circulars and Instructlotu 10c. presentation. Never has ing pantomime. The scenery is made of Own Motori, Reproducer!, etc. told favored critic at private view found color and arrangement, steel and stone, with all the city on the Hectro Mechanical Parts Co. composition and subject, more effectively stage. Footlights and spotlights get their a^ Dcfl. E IHN> WcDiSl^ CI»aio.ll giant displayed than finds he who will be guest life from dynamos and turbines milling of Central Park as he stands witness to the swiftly greater light than Nero made when sacrificing Rome. MATHEMATICS MADE EASY glory of Manhattan. pause, while the clouds are discharg- Tbe Arcaacope—the Combination Triangle Off to the South and West flare great Now with a Brain— will multiply. dlTl«...ni. Write Now Oh, the wonder of the city from the park colored reflections into the shadowed re- CBWTWAl CAMERA CO.. Deft 171124 Se. WtWi»e.. Qinf and then the wonder of the park within fire-brands challenge the darkness the city. Here Robin Hood might dv/ell cesses as of some echoing cave. WHY **FLUNK''? and Peter Pan feel a charm as 'luring as • ljlli.SfeJcilsr "CAESAR'-FIRSTS BOOKS- his finest scenes in Kensington Gardens. So we see the many-sided city at its bath. "CICCRO", "OR VIRGIL" -anJvlhert-.traasUted.wwJfMwwd H you would really see all the spirits of The city that has been the sweetheart of an i^ ENGUSH Ceoplde, cUthboond. S2.M each, mtfaid. city MONONGAHEU NOVEin CO. BOX 299. MONONC^HELA. PA. the wood gathered together in carnival, endless procession of goodly men. The then stand at the Northern limits of the of which O. Henry sang so sweetly and of Printinff Cheap Mall and, half closing your eyes and rising which he wrote so understandingly. Great ,- - ' -ir.|-,circularx. I;»rrr-.l."'ik.|.;.i.<-r. Pr<->S6. on tiptoe, look down its length. Fill your- is Diana of the Madison Square Campanile. ir«crS2fl.Tnh prr-».S^, up.8av«- . ^^ money, Print r.-f^,*i liEt ' ' "'hera. bid profit. All fawv. ruk- (M-nt. self with the full beauty of the fairy court. Great is the Lady of Liberty Light. But iîSgia ^^ r.tf-f;i.-ton,-forr.rv^-'fatalf.c.Tyi'K.caH". It is precisely lighted with soft, glowing greater still is the city over which they • r THE PRESS CO. D.47 Marldwn. Co-n. globes. Here and there stand set pieces of reign. INSYDE Inner Armor TYRES statuary, grotesquely gigantic, forever try- I'll nui-o iin?». Doable milaaira. pff»ent bl^w- When storm breaks at night Manhattan 1 (,..1* a d punctarra. EjuhI/ nppliad In ar.y ti-«. ing in their rigid way to cast strange I Th'>a*«i â Bo^d. DetAJU free. Au^r'M wanUd. blooms: she blossoms gorgeously in the ' Amcr.Accetacflc* Co. .DcpLSa. Cincinnati shadows for each competing light that falls downpour, and bathes majestically. And on them from either side and from across so, when drenching clouds cut ofif our Learn Watchwork, Jewelrywork and the Mall's milky way. view of the campfires of the guardsmen ^ ""' trade commuidliit a (ood ul- Fnaravino As sure as you believe in fairies, they of the heavens, we feel an increased thrill iûgiaTiug irr, «nd jour t4smcm »re »1witb In denuDd. .\iJdreu HOEOLOOICAL D«[»rtm«it. are here. Some lurking behind these in the shining of our faithful keepers of Br«

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January, 1919 ELECTRICAL EXPERIMENTER 675 MAGAZ'IilES GOING UK "«^ Further Increases Coming! NOW IS YOUR CHANCE! with this Issue, the price of the EXPERIMENTER, as announced on another page, goes to $2.00 a year. With the paper market In chaos and soaring prices, printers demanding another large wage Increase, engravings going up 90%, we feel sure that before spring ALL magazines will go much higher than now.

By subscribing now for from one to five years, YOU POSITIVELY WILL SAVE BIG MONEY. Th« prices below are unquestionably the lowest for standard masazinea tbat It Is possible to obtain anywhere. Only by a special arrangement with the publishers are these prices possible and they are good only until The Publishers December 1.5tb, after which date all prices as given on this page are withdrawn. Make up your list at once—do not delay. If you are already a subscriber Will Mail the Magazine asd your subscription to the EXPERIMENTER runs for a long time, you may subscribe for any other magazines by deducting the price of the EXPERIMENTER Direct From Their from the clubs at the rate of $1.85 (the special price allowed In clubbing with other magazines). Thus you can make up any club yourself of as many maga- Own Office to You zines as you wish from the list below.

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676 ELECTRICAL EXPERIMENTER January, 1919

fF Opportunity Ad-lets investigate the offerings will *;nd many rfinarkable opportunities and real bargains in these columns. It will pay you to read and \OU supplies, automo- ' made every month hy reliable firms and dealers from all over the country. No matter what you may be seeking, whether specials ot the momn. accessor: es. the opportunitv to make money, or anything else, you will find listed here the best and most attractive bile and address AJvertiscnirnts in this section seven cents a word for each insertion. No advertisement for less than 50c accepted. Name accredited advertising agency. must be inclatlc.l at the above rate. Cash should accompany all classified advertisements unless placed by misleading advertisements Ten per cent discount for 6 issues. 20 per cent discount for 12 issues from above rate. Objectionable or not accepted. Advertisements for the February issue should reach us not later than December 22. circulation classified advertising rate be- CC rOI A I Mf^Tir^f Owing to the large increase in the ijl IIjV,^1/\I-i lyyj 1 IV^Ci ginning with the February issue will be Tc per word. However, all orders or reservations for a period not to exceed one year, which are received not later than December 20, will be ol 6c per A\ord accepted at the old rate ,, . », ,, EXPERIMENTER I'LJIIIISIIING CO.. INC., 233 Fulton Street, New York, N. Y. frsE

A utomobite Jcct'ssorics Phonographs— Coyxtinued Business Opportunities Fuel, No Carbon. No mys- Build Your Phonograph. "Perfection" high- More Power, Less I rnade $20,000 here past four years making guaranteed. \V rite for quality spring and electric Motors. Tone Arms, tery, plain facts, results burial vaults. Will start you in same permanent Co., Balti- Reproducers, Wonderful results. Big saving. booklet. S. O. Automobile Accessories business without capital. New catalog and building instructions mailed Absolutely no selling. more^^ Stamp brings details. CHarles Murphy, Dept. for ten cents. Indiana Phonograph Supply Co., 3, in Cold Weather with our Bloomington, Ind. Fords Start Easy Indianapolis, Indiana. new 1919 carburetors. 34 miles per gallon. Use cheapest gasoline or half kerosene. Increased Enter a New Business. Earn $3,000 to $6,000 power. Styles tor any motor. Very slow on yearly in professional fees making and fitting a high. Attach it yourself. Big profits to agents. Charlotte, N. C. foot specialty, openings everywhere with all the Money back guarantee. Thirty days' triaJL Air- Oct. 4. 1918 trade you can attend to; easily learned by any- Carburetor Co., 270 Madison, Dayton, one at home in a few weeks, at small expense; Friction Electrical Experimenter Pub. Co., Ohio. no further capital required; no goods to buy; 233 Fulton St., New York. Remover Solves the Carbon job hunting, soliciting or agency. Address Lubricant Carbon Sirs: motor loses power, when Dear Stephenson Laboratory, 18 Back Bay, Boston, Problem. When your Ma=s. knocks, bucks and overheats, don't monkey It certainly was SOME RESULTS. it good typewriter. with the carburetor. Send for a can of Lubri- I've almost worn out a myself writing. i Made $30 a Week, easy money, evenings cant Carbon Remover. Every can guaranteed. Just about exhausted all the paper in this part of America. home. Free Booklet explains. Mail Order Busi- Price Si prepaid. Agents wanted. W. A. Engelke. Used about Gone Busted" buying postage ness. Send stamp. Alec. Scott, Cohoes, New 3257 Bishop St., Cincinnati, Ohio. And stamps. York. Better than any- Kwik-Fix Rubber Compound. Now, I'm a-goina quit, and will never do ever used. Repairs auto tires, Make Die-Castings. Sketch, Sample, Booklet, thing you have it again, or at least I won't promise to an- wires, leaky auto tops, cuts and Proposition, 12c. R. Byrd, inncrtubes, ignition swer all the letters I received from an Ad Box 227. Erie, Pa. in rubbers, rubber boots, hot and thin spots that I put in the "E. E." your garage or by mail 35c. "Quick-Action Advertising it is Build- water bottles. At The letters are still coming in. —The — How Merriman^reeholdjr^^egt^^^^^^^ apparatus advertised has long since been ing Business for the Progressive Advertisers of America"; little story of told sold. Every piece of it. The letters are A RESULTS, by the advertisers themselves publisher. Motorcycles from all over the United States, AND —not the You will be interested in reading this little Motorcycles from J2S up—New and second- ELSEWHERE. Received one today from booklet, which we have prepared for prospective hand Easy terms, large list to choose froiu, all Shanghai, China. Can you beat that. I'm advertisers, a copy of which will be gladly makes. Send 4c stamps fer Bulletin "A. Peer- enclosing the letter from China. mailed to you upon request. It tells you how Co.j__Watertown,.Jlass^_^_ It's a great life, if you don't weaken. less Motorcycle ^ _^ to talk business with i, 000,000 intelligent, inter- I wish to THANK the "E. E."—Some ested and resporsive Americans Agents Wanted circulation. every month men who know what they want and who have automobile tirei, Very Respectfully, Insyde Tyres, inner armor for the money to buy it. Write for particulars and and blow- double mileage and prevent punctures G. R. SMATHERS, rates tociay. Douglas Wakefield Coutlee, 225 outs. Quickly applied. Costs little. Demand 403 N. Brevard St.. Charlotte. N. C. West 3gth Street, New York. tremendous. Profits unlimited. Details free. American Automobile Accessories Co., Dept. 54, IBIiil Build up an Income in Oil—Others are doing Cincinnati. O- it—Why not you? Today is the opportunity. Hel-Met The Kaiser Pin—Latest war novelty. Miscellaneoxis Join our easy monthly payment plan NOW— it Biggest hit out. every patriotic citizen wants Tobacco or Snuff Habit Cured or no pay. may mean hundreds in profits. Write for in- Bing- formation. National Oil Drilling Co., Dept. K, one Sample loc. Wedge Mfg. Co., "KM," $1.00 if cured. Remedy sent on trial. Superba Houston, Texas. hamton, N. Y. Co., SA, Baltimore, Md. beds, tIS Daily refinishing chandeliers, brass Catch Fish. Descriptive folder containing WANTED—Specialties for mail order house. automobiles by new method, without capital or valuable information mailed for stamp. George What have you to offer. Stone Specialty Co., 11 experience. Free particulars and proofs. Write Julian. Albany Building, B oston. Broadway, N. Y. today. Gunmetal Co.. Ave. D. Decatur. 111. Wanted—Small Gasoline and Steam Engines. Manufacturers: Advertising and Toy novelty Hindoo Magical Secrets. Wonderful book. 1919 Cash paid for 1 to 4 cylinder light weight with ^n unlimited field. Protected. 3166 Third limited, asc. Sample 12c. $a per 100. Motors. Y4 to 10 HP. Johnston, West End, edition .•\ve.. New York City. (juick. Dept. X, Lindhorst Magtc Pittsburgh, Pa. Better order ^ Sliop. St. Louis. Mo. Your Technical Troubles can be solved. We Amazing profits manufacturing backyards Fuel Fibre Brooms: Outwear five corn handle all technical problems pertaining to de- Briquettes, cheapest fuel known. Stamp. Cali- Sterling and brooms, guaranteed one year. $1.25 postpaid; sign, calculation, installation, etc.^ promptly fornia Products Company, San Mateo, California. wanted. Keystone Fibre Broom Co., 618 correctly for $1 and up. We invite your corre- agents Bu- Duouesneuqu Way, Pittsburgh, Pa. spondence. E. Duskis, Technical Advice You can letter Automobiles, Windows, Trunks, iii fiS rtau. 1760 Bergen St.. Brooklyn, N. Y. etc., without previous experience, by Transfer Process. Help Wanted Cigarette, pipe or chewing habit conquered. Make $27.50 on $2.50 outfit. Auto Mono- Guaranteed. Write for free gram Supply Co., 87 Niagara Building, Newark, Men Wanted to make Toy Soldiers, Army, Nature's method. brochure. Edw. Woods, TA-300, Station F, Navy anii other toys. Homeworkers on small J. scale. Greatest New York. scale, manuiacturcrs on large ^ Incorporate your business under the common chance for industrious people for independent Fountain Pen Free with a $1.75 order of ink. law. No organization tax; no franchise tax; no business. Enormous demand and future in Eighteen packages, each package contains federal corporation tax; certificates not taxable; "American-made toys". This new American enough material to make twenty cents' worth stockholders exempt from company debts; do work stands out conspicuously. Factories nave of blue-black ink. Trial package ten cts., three business anywhere; directors reside where you been established, people trained, machinery made for 25 cts. Kralovec & Co., 2344 Alt geld St., wish; lowest cost organization possible. Com- with energy and success. Dealers don't want to Chicago. 111. — mon Law Organization Co., 4 Randolph, Detroit, . Mich. handle any others except "American-made We "Quick Process Duplicators." Makes 100 copies goods all year, paying fixed PJices. buy these in 10 minutes. Remarkable time-savers. Thou- Dollars Yearly in Your Backyard. No ginseng, Experience or tools not necessary. Hundred and sands in use. Write for free illustrated circular. mushroom dope. New ideas. Investigate. Par- made complete per hour. Casting form out- St., more Heyer Duplicator Co.. 160-EE, N. Wells ticulars free. ICast 8i;. free. Toy Metz, 313 New York. fits $3 up. Booklet and information Chicago. , Soldier Manufacturing Co., 32 Union Square, Business Worthwhile. I Sta.t You silvering Pyorrhea—H. E. Kelty, D. D. S.. M. D.. pyor- New York. mirrors. Plating tableware; Plans Free. Clar- _^^ rhea specialist for years, has developed a 15 ence Sprinkle. Dept. Marion. Indiana. To Ascertain the Vocation for which you are successful home treatment for pyorrhea. Puri- 48. adapted send for Zancig's Revised Horo- treat- best fying, healing, preventative. Full month's $30 a Week, Evenings. I made it witli a small your birth and 25c. Prof. scope. Send date of ment and booklet. $1. Circular free. Dr. H. E. mail order business—continued my regular job 87th St.. New York. . Zancig. 109 West Kelty, Glenwood & Woodland Aves., Leonia. N.J daytimes. Free booklet tells how, 2C postage. Montl^ly income paid those writing lists of We Have a limited number of beautiful art ^^J^^^cott^ohocs^J^^^^^^^^^ names for us at home, spare time; no supplies to Bictures on hand of Nikola Tesla and Dr. Lee purchase, no investment, expense or other work e Forest. These make a handsome decoration Auctions required; postal brines particulars. National for any laboratory or workshop and should be Exchange. Box 1001, New York; prominently displayed. Price for both, prepaid, ^^_^_ Auctioneers make from $ro to $50 a day. Free Experimenter Pub. Co., Fulton St., New IOC. 2Z3 catalog. Missouri Auction School, Kansas City. Phon-'qraphs York City. liiiHiiDiaaiiiiiiDiMinMiiiiiiw Build Your Own Phonoyraph» and manufacture "Opportunity Ad-Lets" bring quick results. firms are Postcards them for profit. Drawing instructions, Parts, Over 100.000 circulation, net. Other Price List, Blue Prints, etc., complete, sent free making money— so can you. For proof address Twenty Pretty Assorted Postcards 10c. 45—20c. upon request. Write today. Associated Phono- Classified Department, Electrical Experimenter, Castle Co.. N. Locust, Hagerstown, Md. graph Co., Dept. E-i, Cincinnati, Ohio. 2^3 Fulton St.. New York City.

YoH benefit by mentionino the "Electrical Experimenter" when writing to advertisers. January, 1919 ELECTRICAL EXPERIMENTER 677

liiiniiminHimiiimirminnNi liinirnnimiinjmiiimiiinLLaiiitiiiniiitniiniiiniiniiiimiiniiTmrTiiiirninnnniniaiiimrmi— IVircless Scenery for Hire Patent Attorneys lo.ooo ^4" complete, Collapsible Scenery for all BargaiDS— Wireless Coils Plays. Amelia Grain, Patents — Without advance attorney's fe«s. Also, Wire- Philadclplua, Pennsylvania. guaranteed, 90c, send postage. 25,000 Not due until patent allowed. Send sketch for less Coils without vibrators, 4^c, send postage. free report. Books free. Frank Fuller, Wash- Dubs, Pitkin Ave., Brooklyn, N. Y. A. 1534 for Inventors ington, D. C. Best Radio Hook-ups for Damped and Un- Inventions Commercialized. Cash or royalty. Inventions Wantedl Manufacturers constantl7 damped Waves, Amplifiers, etc. Blueprinted Adam Fislier Mfg. Co., 205 St. Louis, Mo. writing us for patents. List of inventions ac- full instructions, 60 cents postpaid. Luther with tually requested and book "How to Obtain a Reiner, Bexley, Ohio. for Patent" sent free. Send rough sketch for free Better stock up now on switches and switch Advertisers report regarding patentability. Special assist- points for that new set. Circular describing the 20 Word Ad. 100 Pulling magazines, $1.00. ance given our clients in selling patents. Write most perfect on the market sent free. Eureka About 75,000 readers, Send copy now. Lind- for details of interest to every inventor. Chand- Secondary Co., 6939 S. May St. Chicago, 111. horst Magic Shop, St Louis. lee & Chandlee, Patent Attorneys, Est. 21 years. 551 7th St., Washingtoti, D. Morehead All-Purpose Vacuum Tubes: Last Advisory Correspondence free. Profitable C. 50% longer; require less hi- voltage; eliminate letters, folders, booklets, follow-ups, plans. Patent Your Own Inventions. Save attorney's STATIC; SUPER-sensitivcI Have one ready Reasonable charges. Pontifex, 62 Frank Street, fees; we prepare applications; furnish full m- Ottawa, Canada. Avoid the RUSH later 1 Satiifaction GUARAN- structions and give satisfaction. Free information. TEED; absoTIVELY. $6.w each—FIVE for "Quick-Action Advertising—How it is Building Carl Larsen Co., Park Row Building, New $25,001 Somerville Radio Laboratory, Eastern Business for the Progressive Advertisers of York City. . Agents, 102 Heath, Somerville, Mass. America"; A little story of RESULTS told by Millions Spent Annually for Ideas I Hundreds MTiMiwniLMiiwimiTtrmimnBTTniiiiHriiBtTmiifiiimmiinnifnniMlMliamTnT^ the advertisers themselves —not the publisher. now wanted! Patent yours and profit. Write You will be interested in reading Appliances this little today for free books—tell how to protect your- ElCitncal Supplies and booklet which have we prepared for prospective self, how to invent, ideas wanted, how wc help Recharge 2 dry cells for live cents. Directions advertisers, a copy of which will be gladly you sell, etc. 212 Patent Dept., American In- IOC. Gilbert, 8 Chestnut, Binghamton, N. Y. mailed to you 'upon request. It tells you how dustries. Inc., Washington, D. C. to talk business with Tungsten Steel Magnets U type. Have a num- 1,000,000 intelligent, interested and responsive Americans M. F. Miller, Ouray Building, Washington, ber of these magnets weighing 2 lbs. each and every month- men who know what they want and who have D. C, Patent Attorney, Mechanical and Elec- will lift 6 or more times their own weight. trical Expert. the monev to buy it. Write for particulars Best quality of work and results. while they last. Henry Althaus, Bluffton, and $1.75 rates todav. Douglas Moderate charges. Advice free. Ohio. Wakefield Coutlee, 225 We«t jgth St.. New York. Your Idea Wanted. Patent Your Invention. Blueprints tor building of Spark Coils from I'll help you market it. Send for 4 free books, to 12" with Instructions. 50c. each. Also J4" list of patent buyers, hundreds of ideas wanted,, for Wimshurst Machines, etc. Also repairs Printing etc. Advice free. Patents advertised free. made and parts machined, after sketch. The 100 Bond Noteheads, lines 4 and 100 envelopes, Richard B. Owen, Patent Lawyer, 130 Owen Bldg., B. & H. Electric Laboratory, City Hall Station, prepaid, $1.00. Southwestern, 1413-H Berendo, Washington, D. C, or 2278T Woolworth Bldg.. General Delivery. N. Y. Los Angeles. New York. 16 printsTit 50 Bond Letterheads, Elttctriclan*. . Send $1.^ for blue 50 linen cards, 50 en- Motor Windings. 10 A, C. Single, two and three- velopes. 3 lines, $1.00. Shamrock Press, 86 Mit- Dogs, Birds, Pets phase, and 6 D. C. or set of ao A. C, 6 D . C, and hoff, Columbus, Ohio. 6 Rotary Converter Drawings for $2.35. Connect- Calling Cards. Your name on 25 high-grade, Ideal Xmas Gifts: Collier, ing and Winding made easy. Superior Electric Fox terrier, B. & pasted bristol cards together with a famous Tan, Pekingese, Pomeranian, Boston. Canaries, Company, Lock Box, 1372, Pittsburgh, Pa. Brown cardcase, 25c. The Barker Press, 17 Gib- Angora Kittens. Send 3c for bargain list. Shady- Electricians and garagemea: You need the blue- son St.. Medford, Mass. dell Kennels, Work, Pa. print: for building the E102 test and trouble finder luuimuminmimniDiiiamDtiiDiiiQiiniumiiiinmnDiii and directions for making tests. Locates shorts, Song Poems l-Vanied grounds, opens in armatures; Oil or water soaked Books secondary cables on ignition units; Traces any Write the Words for a Seng. We write music and guarantee Free—$5,000 worth of valuable books as pre- Sower or lighting circuit; Hundreds of tests can publisher's acceptance. Submit poems on war, love, or any subject. miums. Write for more information and cata- e made with it. Send 25c for blueprint and Chester Music Co., S. logue; it's free. I have many books on Natural directions. The Data Exchange, P. O. Box 1018, 538 Dearborn St., Suite 265, Chi- cago. healing, personal magnetism^ Clairvoyance, seer- 7th Floor, B. Bldg., Dayton, Ohio. U. ship, Hypnotism, Mesmerism, concentration, i m i i iniin i i m ii iiii uiiii mnin i im iiiniimiimiinmniiiiiiiiiniiiniiiniiiniiiDiiiuiiiuiiiaiiiiiiiiiiiimiiimiuij i[miiiiMM'iii'i''iiiiiniii'in"iii)'iiitiiii'iiii'ii'i'iiuiii>iiin'uP''q'ii>"''i''''"''''"''"''''''i''°'"''"°ii"'t character reading, mind power, etc. Tell me your Fonniilas Chemicals wants. A. W. Martens, JX8, Burlington, Iowa. 80 Chemicals $5. Chemical outfits as previously Electricity Made Simple, 160 Formulas, re silvering mirrors, renewing 233 pages, 108 illustra- advertised containing 80 chemicals now again for tion, each dry batteries, luminous paints, mechanics' soap $1 prepaid, or send for circulars. sale at $5. Swimmer Chemical Co., 1849 Park Satisfaction guaranteed. 25c. lists 2c. "Bestovall, Box 543-E. Chicago. M. E. Kraybill, Jr., Place, Brooklyn, N. Y. Boiling Springs. Pa. Formulas for Every Purpose. H. Krause, 2746 Blueprinted Charts—Send 25c for "15 Experi- So. Karlow, Chicago. Novelties ments in Chemistry" and circuar of other new ll^lmlMlIp[Tpl [mlml lIT^1[mrlm^t^llmllmm ''^''tn"^tr^m[^mll[llllllll^ ^B [ | F^^^^^^^P^^^' things. Royal Publishing Genuine Indian Baskets—Wholesale and Re- Co., Box 1054, St. John, N. B.. Canada. For Inventors tail. Catalogue. Gilham, Highland Springs, California. Inventors—Market and secure your inventions Books for Real Live People. Lists free. J. E. Sheridan, through National Institute of Inventors, World lainmiBiiiimnnimFMimiiiiniiimmiimiiQiiiDumiiimiimiiDui iiiaiiinjiitMiiBi iMmnTng^ 417 E. 151st St., New York . o ^ Bldg., New York City. Membership co- opera- News Correspondents Money saving magazine offers. Send for free tive organization. catalogue. F. C. Johnson, 1620 East 68th Street, Earn $25 Weekly, spare time, writing for Legal advice on subject, Mfg., commercial, Chicago. 111. amy newspapers, magazines. Experience unnecessary; trade information In Re. inventions—patents. details free. Press Syndicate, 566 St. Louis, Bookkeepers and Business Men—Something dif- Hanlon, 1201-Arch. Philadelphia. Mo. omtBaiiiijuDiiiuinmrmiminmiiimiiniiiiiiiinmniminnmnmiirfrmnmTnnfiBitmiirTnimim ferent in Bookkeeping. Perfection Business Sum- Attention I I infor- mary. Makes Inventors! have valuable Motors. Engines and business 100% more interesting and mation how you can protect your inventions for Dynamos satisfactory. 800 in 4 cities. John Capehart, two years before patenting it without expense or Small Motors and Generators: 1000 New Motors Frankfort, Ky. risk, full instructions, 25c. H. B. Lambert, and Generators from Bankruptcy Stock, H. P. 55 H World-Romic System, Masterkey to All Lan- Willow Ave., North Pelham, N. Y. A. C. $18.50 each; Yz H. P., $30.00. Batterv guages. Six Textbooks. $1.44. French Chart, 37c; irmmiiiiitTpffiiniiirpirmiriniiiTiiimiiniiiiiiiMiimmnninti iiiiniiiiiiiiiiiii] |i|ini|iiiimiii[ni Charging Sets—Robbins & Myers new outfits, all Spanish, 37c; Aviation Dictionary, $1.50. French- sizes, $30.00 each and up. Charging Lighting Tricks, English Aviation Dictionary, 6ic. Languages, Pussies and Games and Moving Picture Arc Generators, $10.00 each 143 West 47th, New York. 1000 stage tricks with 500 illustrations. Cata- and up. Motors for all phases of current. Im- logue IOC, small catalogue FREE. Hornmann mediate delivery. Less than K regular prices. Learn to Become an Acrobat—Our 10 lesson Magic Co., Sta. 6, 470 Eighth Avenue. New York. Write for late bulletin. Johnston, West End, course teaches you. Send 75c for Lesson No. i, Pittsburgh, Penna. or circular free. Only course in America on Tricks, Puzzles, Jokes, Toys, Games, Novelties, ^ acrobatics. Royal Publishing Co., Box DoU and Cane Racks, Plays, Wigs, Stage Sup- Boilers, Engines and Machinery. Werner Ex- 1054, St. tract Company, John. N. B., Canada. plies, Escapes and Illusions. Large 1917 catalog Mechanicville, New York. iimiiii niTni[iiiBtimimiimn[iniriimiiitimrTmimnimii|TTi nnTmiiniininini i iiiiiBiiir]i How to Locate Oil, Minerals and free. Oakes Magical Co., Dept. 549, Oshkosh, [ n^ Valuable Sub- Wis. For the Hair stances by Wireless; Scientific Book, $3 postpaid. Astral Child Publishing Black Art Hindoo copyright Co., Corpus Christi, Experiments, I Was Bald. Obtained hair growth by an Texas. 1919 Edition, 25c. Invisible Ink. Trick. Free Indian's ointment containing genuine bear oil and Catalog each order. To Get Better Pictures: Read the Amateur Lindhorst Magic X Shop. rare plant juices. Many others have good hair- Photographer's Weekly; illustrated; weekly prize St. Louis. growing results. Will send box, postpaid, with competitions; print criticisms; many unique fea- recipe. 10c. John Hart Brittain, 150 E. 32nd St., BA-300, New York. tures; $1.50 per year; three months' trial sub- Statnps and Coins scription 25c. Abel Publishing Company, 401 onnrniDiiriiimiimiiimiiimiiniiiniiiniimiiiniinniminnnniiimrmiimin Caxton Bldg., Cleveland, Ohio. Stsunps—61 all different free. Postage, 3c. Photo Developing Mention paper. Quaker Stamp Co., Toledo, Ohio. Old E. E. Back Numbers: We have some valu- Mail Us 15c with any size Film for development able old E. E. back numbers on hand as follows: California Gold, Quarter size, Half-dollar 27c; and 6 velvet prints. Or send 6 negatives any 191S—Jan-. March, April, June, July, Aug., Sept., size, 53c; Dollar size, $1.10; Large cent, 1820, size and 15c for 6 prints, 8 x 10" mounted enlarge- Oct., Nov., Dec, price each 35c. 1916 Jan., Feb., and loc. — catalogue, Norman Shultz. Kings City, ments 35c. Prompt, perfect March, May, June, August, Sept., Oct., Mo. service. Roanoke Nov., Photo Finishing Co.. 255 Bell Ave., Roanoke, Va. Dec, price each 35c. 1017—Jan., Feb., March. 500 Finely Mixed LTnited States Apr., May. June. July, Aug., Sept., Oct., Nov.. or Foreign Kodakers: How would you like to get a 9 x 11 Stamps, i2c. Philatelic Star, Madison, Dec, each 3sc. 1918—Jan., Feb., Mar., Apr., May. N. Y. enlargement of your best negatives fi-ee ? Drop us a card right June, July, Aug., Sept., Oct., Nov., Dec, each 20c. 225 Different Stamps 2Sc. Fred Onken, now asking about it. Films de- 546 We can fill orders at once upon receipt of your Carlton Avenue. Brooklyn, York. veloped at 10c per roll, prints 3c. 4 and 5c each New remittance, and if you Satisfaction ^aranteed. Ford's Foto Studio, have not these numbers We buy and Sell Old Money. $2 to $500 each Ellen^hure-. Washington. already, now is your chance to get them, as they paid for hundreds of coins dated before 1895. probably will be snapped up very quickly. Ex- Keep all Old Money. Send 10 cents for new Telegraphy perimenter Publishing Co.. 233 Fulton St.. New illustrated Coin Value Book, 4x7. You may York City. Telegraphy zmd Railway Accounting have valuable Coins, get posted. Clarke Coin taught A Binder for The Electrical Experimenter will Le Roy, thoroughly and quickly. Unprecedented Company, Box no. N. Y. demand preserve your copies for all time. Price, 50c. for both sexes at Big Salaries. Oldest and largest Postage lbs. 200 all different really fine Postage Stamps, school— on 3 is extra. Send for one today. Est. 45 years. Catalog free. Dodges In- Experimenter Publishing 23c. Dayton, East Foxbor Mass. stitute, Co., 2^^ Fulton Street, Seventh St., Valparaiso, Ind. New York City. You bPnent by mentioning the "Electrical Exferimenter" when writing to advertisers. a :

678 ELECTRICAL EXPERIMENTER January, 1919

Scientific Exchange Columns anything for which you have no further use. Read THE quickest medium in the country for buying what you need o r disposing of 1 the«c ads. each month you'll not find bigger bargains anywhere. — Beginning next month, these exchange ads. will be run in the regular opportunity ad-let columns under a separate sub-heading, "scientific exchange ads." This will give exchange ads. a better posi- NOTICE of CHANGE tion and insure their being seen by every reader of the magazine. The rate will be the same as for all other classified ads.—7c per word, with Effective with February, 1919, Issue. a discount of io% for six consecutive insertions and 20% tor twelve. Advertisements for the February issue must reach us not later than Dec. 22. EXPERIMENTER PUBLISHING CO., 233 Fulton St., New York City csir ^ half two K.W. For Sale—Hydroplane. Length sixteen feet, For Sale—6 H.P. 4 cylinder Universal Engine Swap— Electrical goods. Want to beam 5 feet. Electric lights including searchlight. and amp. 60 volt D.C. Generator, $250. Will Transformer and Rotary spark gap. Warwick, 55 Automobile Steering Wheel and controls. Name: take typewriter or wireless as part payment. 2535 loth Ave. So.. Minneapolis, Minn. Sea Gull. Double cylinder Gray two cycle, Herbert Lauber. Geneva, Nebr. Wanted — Wireless transformers, ammeters, high speed, twelve horsepower motor. Speed 20 mi> apparata or small camera ior quenched gap, etc. Sell or trade Automatic Swap— Electrical per hour. Decks and bulkhead mahograr.;; fi. Photo Button Machine, cost $150; also Automatic field glasses or telescope or what you have. ished and varnished. Double waterproof Stereopticon, capacity eighteen slides. Prefer hatches Lloyd Solomon, Cordele, Ga. Fastest boat ot her class on Indian River. Win- Wireless goods. Radio Amateur. Marion. 111. First Twenty Dollars takes Goodell-Pratt ner of many races. In perfect condition; just Wanted Screw-cutting Bench Lathe. W\ painted. wait bench lathe. Same as new, been in use only one — Don't until someone beats you to \ely, Danville, \'a. month. Am buying large engine lathe so must G r it. Shipped for first $200 check. Atlee GuUedgc, boiler c/o Coast Guard Station 206, Fort Pierce. Fla. sell. C. C. Cole. Whittier. Cal. For Sale— J4 H.P. turbine with tlash and coniienser. Want cm ni graph. Joe Martin, Hop- Trade—Movie Machine and Seneca Camera for For Sale—One set E. I. Co. S. P. 2000 ohm kinsville. Ky. wireless goods. Frank Gaede, Winamac. Ind. Phones, new. $2.50. One 120 Egg Electric Incu- Wanted—Wireless goods, describe fully. Will bator, no volts, $18. One 3 pole 75A Knife BUcksmith Post Drill. $5. 191? 9 Volume Ma- pay cash. Merle Hawkins, 1015 Prescott, Canon Switch, $2. One Small Moving Picture Machine chine Shop Library, S9. Bosch Magneto Twin City. Colo. with 100 w. no v. lamp (without reels), $2. One Motor less carburetor, $15. A. Ryder, Box Indian large Electric Bell. $1. One Boy's Mechanic Vol. 111. Wanted— Round Audion, i K.W. Oscillation 58. Argo. 2. $1. One 2 cap. no v. Electric Transformer, Aerial Switch, Rotary Gap. Eugene Stove, $8. Edwin Exchange—Winchester .22 Repeating for .22 L. Murrill. Lewisburg. W. Va. Beckley. Milton. Pa. condition. Panaro, 1478 First Automatic. Good Will Exchange complete motorcycle engine for i Sell— dial omnigraph and other things. Her- Ave.. New York City. 15 Johnson skates. W. A. Schoenheider, ' srr, Biirlingion. Ontario. 5431 So. Swap—Two $5 Erectors, books and magazines Ashland Ave,, Chicago. for phonoeraph or offer. Beaver, 556 West 184th Electrical Laboratory for Sale. Send for list ot Amateurs—Bugs—Send stamp for, my list of apparatus and parts. Ray Wengel, Doty St.. New York Ciiy. ^^ 29 W. Radio Apparatus, Electrical Goods, Ancient and St., Madison. Wis. Exchange— 2a Ansco Camera with leather car- Modern Coins, Swords, Arrowheads. Chemical rying case. Mecanno Set 4; 29 Test tubes 1x6. Will Buy—No reasonable offer refused. Tubu- Laboratory. Rifle, Movie Projector Lens, etc. VVant good wireless instruments; receiving pre- lar Audions, other makes also, variable con- l-iither Reiner. Bexley, Ohio. Cook, Tren- ferred. Letters answered. Kenneth densers mounted and unmounted, Blitzen pre- Marionettes, miniature people who walk, talk, ton, Mo. ferred; Blitzen amplifying transformer. Audion sing and dance. Five professional figures. Will impedance coils. Sell now, give description and Sell—New $25 Electric Train, $10. Harold Tin- sell for cash or exchange for Smith Motor time used. State lowest price. Aubrey Tholin, outfit. ke r. 3448 Aldrich, So-. Minneapolis. Minn. Wheel or similar The Wallaces, Baraboo, 1339 5th Ave., Rockford. Illinois. Wis. Edison Exhibition Motion Picture Machine to Exchange—Want chemicals, chemical apparatus. Wanted—A few old hand stereoscope views. 50c Bargains—New $25 Stewart Speedometer, $15. motorcycle, or typewriter. Valuation, $85. H. E. each for certain kinds. Write for information. Book and others. Write Worth Bailey, Park Pa. Robinson, 126 S. Stewart. Sedalia, Mo. John Murray. Remington Hotel, Eddystone, Ave.. Johnstown Pa.

BOYS, LOOK! Eie^ctri^ motor 50^ CARNOTITE Some hummer. Develops wonderful power. Will run your Erectors, Meccanos, etc. Works on 1 to 6 dry cells, storage battery or A. C. transformer. Mounted on hardwood base. Mineral. ) The Ameri- ( Radium Has % In. grooved pulley. On two cells you can Pitchblende found in Colorado, can hardly atop It with your finger. Runs all kinds of toys. Has nickeled steel frame and from which Radium is extracted. copper armature. Put 50 cents In stamps In an envelope. A generous piece, enough to con- I7DCI7 A 3'/2 v°l^ tungsten flashlight duct exjjeriments, such as affecting r IxILEi lamp If you order at once. photographic plates thru opaque Use Coupon Below. Return mail will bring you material (similar to X-Ray pic- first by Sir tures), made W. C. D. WOOD ELECTRIC CO.. Dept 60. 441 Broadway, New York City.

: Send me Crookes and Mme. Curie, is fur- SIRS a MONOCOIL Motor. Enclosed find 5u cents. nished in neat, wooden box. Name Address URANIUM ORE (Radio-Active)

Containing about 35% of pure CORE WIRE Uranium; also Radium and Va- We h;ive been fortunate In securing thru auction several tnn.s of guaranteed pure, double annealed Norway Iron Core Wire and are selling this wire to "Experimenter" readers nadium. One of the most rare and interesting minerals. Twenty At Pre-war Prices 20cts lb. in glass milligrams are furnished This wire is just the thing for spark colls, transformers, etc., and it Is, of course, a very much vial protected by lead cover. more superior product than the usual iron wire. We absolutely guarantee the 'luallty. If you ever thought of building a spark coll, transformer, or similar apparatus, now is the chance to get the right material for 11. As far as we know this Is the only lot of Iron Norway Core One box of Carnotite and one Wire In the hands of any dealer at the present time, and none can be gotten until after the war. We have only two sizes left vial of Uranium Ore as described 26 INCHES 36 INCHES above sent prepaid. 50c. Thickness about No. 21 B and S If either of these sizes should be too long we advise c.itting the wire down yourself by means of shears. It will pay you to do so as real Norway Iron Wire, sold by a few dealers last year, brought from 40c to 50c a pound. American core wire now sells for from 30c upwards per pound. SIDNEY SPECIALTY CO. As long as the supply lasts we ofTer this wire as described above to our customers at the very low price of 20c a pound. Order at once. 233 Fulton St.,New York City ELECTRO IMPORTING CO., 231 Fulton St., N. Y. C.

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

January. 1919 ELECTRICAL EXPERIMENTER 679

ILqailllHIIIIIBIIIIBIfllBI'nmiHIIIininilBIMHlHilBiVillllBllHl^ EXPERIMENTERS

A Sample of What You Can Do With This Outfit This illustration, mada from an actual photograph, s h o w • only a very few In- Btrumeiits that cftn t>e made with th.% Boy's Eleotrlo Toys: Electric Pendulum, Electric Telegraph, Current Generator. DancingE 1 e c L r 1 G Spiral, (ial- vanometer. Space dues not permit U3 to show the hundreds of oxperimenls that can be performed with this wonderful outflt.

The **Electro** Radiotone HIGH FREQUENCY SILENT TEST BUZZER This instrument givt's a wonderful high pitched MUSICAL NOTE in the receivers, impossible to obtain with the ordinary test buzzer. The BAI>IOTON'B Is built along entirely new lines ; it is NOT an ordinary buzzer, reconstructed in some manner. The EABIOTONE has a single fine steel reed vibrating at a remarkably high speed, adjusted to its most efflcient frequency at the factory. Hard silver contacts arc used to make the instrument last practically forever. Yes, the RADIOTONE is SILENT. In faef, it is so silent that you mtist place your ear on top of it to luar its beautiful musical nole. You will be astounded at the wonderfullv clear 5iJ0 cvcle note, sounding sharply in your receivers. To learn the codes, there Is absolutely nothing like It. With the radiolone. a key and one dry cell and ANY telephone, a tine learner's set is had. Two or more such sets in scries mil alTord no end of pleasure for intercommunication worlc Shipping Weight I lb. j. — -. Eadiotone aa described each SI Qfl IMMEDIATE SHIPMENTS «p.»/V

The "Electro" Telegraph

is not a toy. but a practical, honestly built telegraph outfit, which not only somids but works like the big commercial instruments. By studying the code for 30 days you can become a first-class telegraph operator. Such operators are in big demand now. Outflt consists of TWO complete telegraph instruments each measuring SV2 s 2'^ X 214. All metal parts are liigh- ly nickel plate4, including key lever. Note hard rubber knob. Telegraph Code Chart, telegraph blanks and connecting wire comes with set. but no batteries, Outflt works on 2 dry cells (one cell for each instrumentt. The "Electro Is the ONLY Outflt that works both waj's, each station can car no s\vitcJies, no extras. Nothing to get out of order. Guaranteed to please you or money Ai or* baclL Price Complete as Illustrated (TWO INSTRUMENTS).. \l /S Shipping Weight, 2 lbs. npx*^0 IMMEDIATE SHIPMENTS

The **Electro'* Codophone (Patents Pending) What this fl^^ 5h1 rkC\ remarkable ^S^BmIP^ U/X««./\/ Instrument I9 ^^^^^^^^ and does. No. EX 2002 The "Enec- ELECTRIC TOYS" contains enough mate- tro" Codo- HE BOY'S phone is rial TO MAKE AND COMPLETE OVER TWENTY- positively the 1 \ with- only instru- FIVE DIFFERENT ELECTRICAL APPARATUS ment ma d e J out any other tonls, except a srrew-driver furnished with the outflt. The box that Willi imitate a r.iiO contains the following complete instruments and apparatus which, are already | assembled cycle n o t ( exactly as Studeut's chromic plunge battery, compass-galvanometer, solenoid, telephone heard in, a receiver, electric lamp. Enough various parts, wire, etc., are furnished to Wireless receiver. make the following apparatus : The Electromagnet, electric cannon., magnetic pictures, dancing spiral, electric loud-talking receiver equn>['cd with a horn, talks so loud that you can hear the sound ail over the room, even if there hammer, galvanometer, voltmeter, hook for telephone receiver, condenser, is a lot of other noise. THAT'S NOT ALL. By lessening or tightening the receiver cap, a tone sensitive microphone, short distance wireless telephone, test storage battery, from the lowest, softest Qualitv. up to the loudest and highest screaming I shocking coil, complete telegraph set, electric riveting machine, electric buz- Bound can be had in a few seconds. zer, dancing fishes, singing telephone, mysterious dancing man, electric jump- FOR INTERCOMMUNICATION. Using two dry cells for each Instru- i ment, two Codophones when coiniected return I ing jack, magnetic geometric figures, rheostat, erratic pendulum, electric but- with one wire and ground, can be used fur iriienommunication between two houses one-half nule apart. etc., terfly, thermo electric motor, visual telegraph, etc One outfit alone replaces the old-fashioned learner's telegraph aet, coa- I This dues not by any means exhaust the list, but a great many more ap- eisting of key and sounder. I paratus can be built actually and effectually. The "Electro" Codophone is a handsome, well made instrument, fool With the instruction book which we furnish, one hundred experiments that proof, and built for hard work. Contacts are of hard silver ^ inch in diameter, tliat will outlast the instruiuent can be with this outfit are listed, nearly all of these being illustrated made There is also a neat code chart and full directions enabling any InteilU i with superb illustrations. No other materials, goods or supplies are neces- Oent young man or girl to learn the codes within 30 days, practising one- sary to perform any of the one hundred experiments or to make any of the haJf hour a day. I 25 apparatus. Everything can be constructed and accomplished by means of Sizes: C^i x 3 x 2«^". Shipping weight. 2 lbs. The "Electro" Codophone as described, complete $1.50 I this outtit, two hands, and a screw-driver. I The outfit contains 114 separate pieces of material and 24 pieces of finished "The LIvest Catalog In America" articles ready to use at once. I Our Dig. new electrical cyclopedia No. 19 is waiting for you. Positively Among the finished material the following parts are included : Chromic salts the most complete Wireless and electrical catalog in print today. 228 Big I for battery, lamp socket, bottle of mercury, core wire (two different lengths), Pages. 600 illustrations, 500 instruments and apparatus etc. Big "Treatise on Wireless Telegraphy." a bottle of Iron filings, three spools of wire, carbons, a quantity of machine 20 FREfB coupons for our lliO-page FREE Wire- less Course in 20 lessons, FREE Cyclopedia No. 19 measures 7x5 screws, flexible cord, two wood bases, glass plate, parafflne paper, binding V4". Weight % lb. Beautiful stiff covers. posts, screw-driver, etc., etc. The instruction hook is so clear that anyone can make the apparatus without trouble, and besides a section of the iustiuclioa book is taken up with the fundamentals of electricity to acquaint the laymau with all important facts in electricity In a siniple manner. ELECTRO IMPORTING COMPANY We guarantee satisfaction. 231 Fulton St.. New York City The si7e over all of the outflt is 14 x 9 x 2?4. Shipping weight, 8 Ibs.ffCnn I enclose herewith 6 cents in stamps or coin for No. EX2002 "The Boy's Electric Toys." outflt as described ". <^o,\J\3 wliich please send me your latest Cyciloi>edia Cata- IMMEDIATE SHIPMENTS log No. 29 as described.

231 Fulton St. NAME ELECTRO IMPORTING CO., NEW YORK ADDRESS

IIIHIII STATE EE. 1-19

You benefit by mentioning the "Etec^cal Experimenter" when writing to advertisers. -

680 ELECTRICAL EXPERIMENTER January, 1919

,M DoubU Action Drf*MjfclMj*«i Trim "The Baby' The Border Bandit Books Your Own Hair With the A HANDSOME AND MOST EFFECTIVE WEAPON Thrilling Adventunt and Darinp DaMls of Notoriout Outlaws Utility Safety Hair Cutter Measures but Cuts the Hair Any Length, 4^4 Inches lonf Short or Long— Save* Its Cost First Time Used. PRICE ONLY 35c POSTPAID EXTRA BLADES 3So EACH. If sou :an COMB yoor hair you can TRIM you r oWTi hair with this marvelous Invention The irriUTY TRIMMER will PRICE Oe CENTS OR THE FULL I A BOOKS cut hair ONLY » 4 HA POST any lenKth you di £9 EACH ; SERIES OF liJ FOR «b4iUU PAID lonir. tlnlah tho job as nicely as any barbci This- ..Hm of book- .. and in one-fourtb the time beforo you ts of the d d urine JA deeds of notiinomoutU«-s. Eiw:b ho full i.airo illustratio own mirror. The ladies con cut tho children's hnir ut home In • of the»e booka cannot be anything but bei ;fioiaJ upon the Jiffy; can bo used aa an ordinary raior to shave the face or Apiah chara..-ter9 of the moat .0^ around roDthful readera. Tber do not s>'irif y tbo l the temples and neck. Sharpened like any riurir; can be ear- andêtoctirea: the contrary. Uiero Is ned in the vest pocket ready for Inalant uce and will lust a lifetime. on an o he draim frtitn very -J TakMrtonlv story that cannot fail to have wholesome eSi ' • - front of a mirror. If necessary, and use tha a . < Prte of thaaa boelia la 2S eaitts êMibr« u would a comb. Push it throucrhthe B Ir^Z Outlaw, KirjiT of the Bandits, by Harry Rawkeye. _ . _. . - Uon tho bolr Ilea, but Waver Upwart. oartridffM J- T* TO cut lone hair, B 2. The I>alton Bo>-» and Their Gmng of Deapcradoes, by Uorrv a«WKeya.Hawknea Arst moisten tho hnir and comb It, lo It will U« Tt* M« B«*T DmW* A«tlM HMtmm trtwma RvmImt bu been prt^Joeod u> mMt B 3. Buffalo Bill. Kine of Iho Scouts, b? Harry Bawkeye. close to th« bead, then start cutting with downward cuts as high aa lti» #»«r ^'£,-*-»*in# J«iiis-1 JiJr > rcvoirer that wouU combine ucatl bu* uid B i. Rube Burrow, the Outlaw, by Harry Uawkeye. you deaire, evenly all around the head. Finiab around the necE aod -iiA ««*ru»J teraDlea with UfSt -e^jti U:« («»turt« cT £fncJ«>ey and PrcctlcaMlltT. It l» B 5. James Brothers i Life of the James Boys), by J. W Boel aaquarecut, like a barber. " •OaU is m*. Ml m Juft M •a«et'»* »od •«mc«^lp u the coost e»p«c«.Te wMpoo B 6. Younger Brother I -nio Border OulUws andCompanlona'of ItlB impoeelblo to leave any "nlcka or "cat steps" In your hair ET«r» lMl7. FV«Bk and Jaaao With thin device, acui boT. •bflwJd h*v« ft r«TolT«T wid thcûld know bow to use tl aa tho handle ffuard ffuldea tho cutter blaue eveoly over the acelp. . Cbcra t» BO Mfw or b*tur,MM ibmI* thaa ibi.. ^remi B 7. Cowboys of tho Wild West. Life A feature 1« Iw»»fet7 on the Texas Plains, by Barry HBwk«» f- -... Lives " very cloBo, until •**»~ ^^..^'^^•«^*?£*'**".*»' newi The Story of His Advi-nturea. With the ffuord teeth. ahave the face i MB and OMd to b« tlMr»i»bty ftppi«elfti«d. Tt>« uamuiutloti used i« the atMd- BIO. James Boys and Their Dannc Deeds. Jamea Ed«v To or neck It can bo .rr raioi Tt-fl(hr> Ubort) cainnw* obtBin«bl« Bll. puthkws. revorsintr tho blado in the holder, th( uHiDg being to _ ra ftorwbcra, or rou m«r obtain U)« The Allen Their Career and Crime of tho Blue RJdge Uounlaloa edge _ carttidfB* frea « te«trld«»« cm b« ahlppM] oolr br •zprvui Th« revolver Baoonshiners. by James E>dnr. „.,^t^Mtt^ back of the holder, expoalnir tho entire lud«, except each comer, To hone place the bladeln holdi yîft •**?? ""ô^ >f*du\«. .T>.« OMntxm of U>« chwiuic Biech»ni«m I* ex- BI2. The Auto- Bandits of Paris. Most Amaxinf True Story of CHm» the with the cutting edge to traoMT rmoia wad abaoiaUly rvluble; alx well »imed sbot* c*o be fired in nuuiy B13. BuffaloBillandHisThnllinj-AdventwreslnthcWild Weat the back, moving the blade out until tho cutting vdi l9_ cl..nrof_ _ _ theback of the u by NcbrasW- N-^ uHi.nl ••rowb. TTi* r«TolT#r tl Terr well cor-jtroetej. holder, fhcn hone In the manner; fintah on n Mr..;, na wiih tin . with fip.eai i-i.-kcl i Intfd fiutcd B14. Northficld Bank Robbery by Goto Yoonaor and Cor''-'''-'-^-^''^- »it=Jer. it Pur.r.. losota t»4rr*l of n-.d wrutî cMr SO. eMl kr lull »MtMid t. JOHNSON SMITH A CO. Jami-a Boys The Missouri Bandits, by Edg«r James. T/ieCONJURER'S CASKET 7-in-l Combination Bill Book . BuiditA of (^litcaKo ;A._ Correct_ Account of tho Greatest D.tocUvo With Name Stamped In Apparalui and Directions for a Numbor of Mysttrious Tricks Worlt in the Hist-iry of Chicago Police Korcc, by Jame.A'iovBh.; n^l^d:." 50< Great Beattic Murdor Ca90._A ThrJllinu . 1..^°- i^'^-P."^!'!?- tnougb for an Enlira Evniog'i EnMrlainmont . AThrlllinK-Sifyot.M.l-rb'S'ofleUf;^tory Jf 23-Karat Gold Letters of Henry CIi Tbe Sonaafonal Story of Bueiah B°&Sd! ANYONE With a view of Retting our name still more widely CAN DO THEM. PRICE SOc POSTPAID to new customers, wa JOHNSON SMiTth & CbT.'Oept. c} 54 W. Lake St., CHICAGO known, as well as secure G«t i.'-i* C«R;-jrrr'» C»Cia*l It cDnt«in« the «pp*f»tu» ,^^\ mako this REMARKABLE OFFER of a handaomo fof ••Ten lir«t-r«W tn.-»j, uvrluding The Disircetrins t rfrTTQ,. LeathiT Combination Bill Fold, as tlluslrated, Hn>t. tb*t. wbea ptoced oa the Lapel of roar mat with thi> ownar'a name atampad In 23 Karal MM Cron aifbt at will; tba H^cic Vm« ud BaII Gold Latlartng. for ONLY &0 cents, postpaid. inck B#U t«pl»Mduu»de.»nd JT Here Is an all "njund useful combinaiion that MS nolmhat tb« Ud hM dtM{>pr&T«parena» Tha most wonderful and In- ing bills in. (2)another pocket for cards or tickets, fourth (or mis- Obcw KhwMt u two: tJbe Woo. Oanlous Camera mada (3) Bllll another for che^rka, (t) a dvf ol Cwd Tnck (« ovd ! pUc»d to wi cellaneous papers and memorandums, there ia •miope. kDd wheo opened »n eatirely It ia but little larger than a (5) a short center panol oockct with clasp for dUrerDoi card aluretber U found): The watch, which it closely re- postage stamps. I6i an Identification card with MMMwariBc Cote Bos la coin la plsccd Bemblt'8. You can carry roomtor your own or dear ono'e photograph, and ^Jfav^boU weodM tertel. and. when (7) n^movftble Catendsr by months. The Iden- 'to bate ta/iisbed the Expo about In your tification Cord and Calendar ere prott-cled by a pocket and take pic- transDArent covering, the whole folding up into turee without any one a compact apace of 3x4*i inches. Price SOa HMBMtoad 1 lino (add 15c for each additional MB Ptaay that d«hea the la>. being the wieer. with name In ** CTwniatMa UiMpeada (ram th« pmlm of Oi« hand. nose, check llnei Also obtainable In very superior quality. VMUaitaCoto wall rinrh^r !FJiJ**j9?2-Gob'»* •«* TVick :; coin « dropped h,=JV«uS. Pletura Sl.OOp. pd. CytT.aad twatha wUer ia powS ool the com haa One Cant a Ukt St. Chlcap -anlaheSTr Fg fprfnT^S GOLD NAMt Johnson Smllh & Ca. , Dipt. E2 S4 N. . " ' ""' '« B^lde. the KARAT Sg' .Vi jer'"^'* "^ '^'*- tricka conti^^ned In the îbT The Expo loada In dayliirbt with 26 Exposure Filma. cost- matroctJon.. OTte^ fw "hich rou can ea>>ly make <.r procure the r.eeea«*ryappa Ins Z&c. thuB the picturo tak- NEW rstIM We alao aand the aecrrt of perftmiirit thr. e wonderful sii^ rrn^t. ins part of a whole day's out- BOOK ON SPLICING r,ir nominal ROPE lOWMSOW SMITW a CO.. Pept. n »« W. L.K. St!. cjSlCAcb may be had for tho of 26c-Ono cent a picture. USEFUL KNOTS, HITCHES, SPLICESe ETC. to Eip Films also obtaln- ipliclly itaelf to op- ooirr .^^^ How Different Knots Are Made and What Comlorling to lh« Fccr rato. Take* pfcturea through tha LlIMir .X^fck They Are Uaed For. Knot* to U«* ontf ELECTRIC INSOLES and Healthful HI. where the Rapid Fir* Lena H Knota to Avoid. photos (6/817/8) may .^''^)^y^ ited. Tbo ^*'*'20C _/^Ji^ '^/.'iHi A moBt practical handbook gWIna oom. Vou »tU rieier iuffer from Cold Pe«l while you wear ilusc ilargedtoany alio. plete and slmplt.' direction for maklna Electric In»oln Any sire. Comfortable even In a HkIh all the moat uspful knots, hitches, rig. sbor. AkernstA plates vt copoer and zinc Bcnerale a QUICK AS A Fu\sH vs^:s.^ 'rcT^r°iSVis^^. ging, apltcea. etc. Over 100 lUuetrs- mJld and pic&sa/il fonn of electric enemy thai pruiiiotes F.ndorsed professlonala world over. Thorouithly practical— br amateura and the tions. AJInboutnlre the cliwUilon of the blo^rd and thus tones up ihe eiiur>.' printinft ana developina of nlma just the aame as ordinary eameraB— In daily use by police, newspaper reportera. detectlvea. and tho sencral public. Important rope attachments. iyatem- Posltltrly Prevent Cramp, avert Nerve Trnuhifs, ' - -- ' -"" " '"- - - reportera bea&itB 'ha»V'beenI Vecur«d"'with'thVWatcir'CM" by erierirlsinB lashing, blocks, •ave you from Colds and Chltls and dispel Rheumailc Produces clear, sharp neffallvea indoor* or outdoors edual to any camera oo tbb taokles, etc. 37 Pains Hating obtained a larRp stuck we arc ahk- in prico hotwlthstacdinu. market, b1;(- or Heraldic Knots illns- reduce the iirice ig 2Sc per pftir or better quality. 50c 15c, 25 EipoiurM, 2Go Expo Watch Camera (O Rfl f't-^S, 10 Eipoturei treted. Of great value so«tpald. . IknTsherg Pockal Csrrflng Caie, 3Sc fmUit 10c O&ivU Isalhsr mechanics, rlgsere. Lakf Strret JOHNSON SMITH CO., Dept. E2 54 W. Lake St., CHICAGO JOHNSON SMITH & CO.. Dept. 12. $4 W & campert, boatmen. Prto-iflflp. oil. CHICAGO St. .Chicago DREADNAUGHT MnMn Smith & C«, ,0«p1. E2' 64 W. Liki ' THE FIGHTING THE IVSINSTREL SHOW INVISIBLE INK i.vi. iii.'i'i'niia3 Warship Sansationally Raallstic! Exact Model of Modern writing can be READ i Ir.l f.T' The grea .est toy eon- the wT'C'.-vs MAKES NO IN A DARK sation of the day. HAJML Cabika t« aeeiL ONLY iBtaaa yoa know tba a»- ROOM; writing shines The Fishting Dread- qpt. laralnabto for maer naught is an exact IDU Art. Quite Invisible at kaadocbar pmat . model of Uncle Sam's or»Mtiini awaj fr-os r^''~f daytime. Very remar'.:ab!e. latest fighting- mon- «7«l G*«i; fiS fr : irl'- prac:':a. .:<«•. Or'ii' ISe tee totlle; t lor 40cpoilcald. Bter. It carries eight JOHNSON SMITH & CO Dopt. 12 S4 W.Laka St.. CHICAGO big guns, each of which flashes, at cor- ,_,^. of genuine bumt-rork comicalities Ihnt will highly appreciated by all who laugh. PRICE, including caUlog of rect intervals, from _, cojoy a g.iod New all kinds of wigs, musks, mske up gm.ils, grease palnla, etc., fi.r nmsli-urs. twelve to twenty times. Extra ammunition always obtain- Only 10 canU poatpald. JOHNSON SMITH ^ CO.. Otpt. E2 54 H. LaktSt.. CHICACd able. Absolutely harmless. Can be operated indoors or out. tn batileehip in action, Vamping Nuw. boj8 I Here s your chance see a and STAGE the bfnt ot it in you can OWN tlie ship and command the firing Sneezing Powder voiirst'lf! By havinn two or more BattliBhipw. nou can arrange MONEY . PIANO K.XtnXINti NAVAL HATTI.h.S in 'oui own home. Price of PLAYINa Card Warship and Ammunition, 16c. three for 40c, or a fleet of 12 MAD I ships for S1.50 postpaid. Extra Ammunition, 5 cents per pkg. \f (^ r!??5 \ I No TaaoKar Naadad ^^m^ lASYKABT ^HfiL ttfrprialngiy tlmpla Syataitt rwautJ bavlac najlarlil tbalr Ifoalcal Eaocstlen oaad notdc«v*ir. fc^r nliii ihi iHoi'w aav VAMPIKO CAHD ipUcliX the urd apHsbt oêr the p>>i MUSICAL KAZOO MAGIC FLUTE With tho Munksl Kaxoo , . aaoal to a 1 Wonderfully Sweet able Ifter t; ng It a few tunea . . ousprtictico mbnteov^ " irntirvil' 0«lT 1(«n.p.od. Je Toned and Musical "..,, ...... «=, —....jing to bear their i- P.'" . marks, as they novsr suspect the real With a bunch of these bills. It for each person of limited means to ap- Skeleton ':»t, Nm Other «our'?e. but think they have caught It one Serpent's Eggs Mystic pCrument pro- fr'jm tho other. Between the laughing pear pronporous. By flashing a roll of ices ewoeter and sneexlng you yourai-lf will he huving these bills at the proper time and peel- .n>ln. tho time of your life, For partlas, polltl- ing off a gt-nuine bill or two from the 1!Z •-if»:a. «hich are nusic, whether It .MJtnldo of tho roll, the effi-ct crested lea to ftngor. la aitnpllcUr t bo tno joyous eal maatlnga. car rides, o no I^TKer than s excellent di:. will bo found I'. !.. nil that can br dc- Produces music You itOB of a quick- If of I i.[..!ak, lautfh nir.'d Prices, poatpald: 15 Bills lOc, gram ot (I'^t blow into It, but ainff. <.r i-p or the eol- ., .„ thi- f raalaal loha out. Prica t2co ly desired Imitallun Used with Bllll 25c. 125(0; oi S3.50lhousani). O A t il . -jin strains of a for SOc. JOHNSON SMITH * I 50 SOc. r Excellent for Tocol or ac- other musical Instrument, the effect la onrU Mad twiat« about in a mo«l nova. At command of operator will lir cornpanlmnnla. either with or without charming. Full pnnlivj Instructions for Watches, Clocks, Etc., Other musical ln»trtunenu. Prk«1Scp. pd. playinK sent with each Instrument. Make Your lifelikf manner, hi bv. lOc Md. down, atamj up. dancc, etc. J. S. A CO. '^ '•

I Visible by Night_ JclM^wW-'^"âclentlflo world. Ulth< tlollr unobtalnsbre aicspC at an exorbitant pries, we hive at last A Great Curiosity PAlfiT. which, applied to In. proXcCtîprodu r"marki.bre CIGARETTE ojof article rays ot while light, rrndcrlng It perteotfy vlstbla ROLLER a any amlla BRILLIANT if BMINli. QulU \ -ifj- neat and handy Wl'IkIis i'.- • THI bARKtri TMt NlOhl. THE MORE Midget Illustrated Bible applk'd to the dial of rour ( It A little I'l a quarter of an oiuice. H makea by night. You can coot the push Ths SmallMt Bible In watch lock will enable vou to tl tVietlme Um Worid r riKBreties than you can buy and ric llghta. match boxee. and Innumerabla button I switch platea of your eh Ttm HIdcat BIbU la a perfect tfetn. and work r.. .:..-, quickly. You 10U9 Cruclflxes. Luminous Rosaries, eU, a of ihctn oiwlly and other articles : make y. arti'-lpn Price 2Bo Larger rt. It faabovi the •li.e of a poatue 8t*mp and I', uî- Just the tobacco you [ircfcr and Botlli- conuining sufficient lo rm .T,.rnl small coBflfta .TWO HUNDRED of llh Co., D«ptX2 MW.Laha Bt..CI>lc«0 AND n^Y PAGES ttnis httvo nicer "smokes" than rtatly- aiiea SOo u^d tl postpaid. Johnaei a tba NEW TE9TAH£NT. profoaelir iltuatiated. Having Tbla Ultla Blbla la a wonder. It la uld to brlos iiiadf. and more of them, bc-^ldt^ o-w-t.^t : try rood talek to the Mua' be a«an to ba apvradatad. Priaa. anly 11 oan ta , about half of your money. Just one lor All the Latest Surpris ng and Joke Novelties eA* < mnm aiMa* 90 c««tai d«tr> %•• ^•^ ***00 .^ *90 for t«.00. Good and inaky your ciiiarettea Just to your "f*"'- "'- '-" *• "- ^ ' P.Miny (. . ...' icd "" BOaay cae h-e c:.*'^ ' ^r-ee lT4«»t 6fttaa arao=«t marli. rpenls E^g., box 10c r ckaicb'acQoaint- Price only lOc or 3 for 25c pottpald. with full inîruc- Phai. S«"^ fTT_» few a-d rry Er Mlnli.1.-.- Waur FisU.1- 20c iv«ry lifellliel Mysterious Tumbler and Vanish- iOHNSON SMITH & CO. Dept. C2 54 W. Lah* St.. CHICAOO Cleopatra's Snake . .,, OHNSON SMITH A CO.. DepL E2. 54 W. Lake St.. False Mustncbe (fw^l Tour frienda) 6c ing Cdin Trick 26c Mirror 'take peep) lOe Ford AutoPuiile (Latest) . . , 16c Magic o&e MysterIouj> GhoHt. shines at night lOc Magic Plate Lifter ZOc Brander . . Thumb .INKLESS (vi-ry 2Cic Imitation Gold Teeth . 8 for lOo PEN Ruhher Raior formidable) . '• Latest Novelty: Aerial Balloon Griat Burglar Puitia lOc i. •GiajO'E — Rubber Dagger 'aenaatlonaJ) . . 20c Flli-B rrmrcfully In nr outd'v-rti. Wire puziTrs, lOc. S2 dltTarant, ohe) . 26c fr -.:;. Klta.f. VERY LATbST SmsATlON IN liAh- l>x)kbarlcroiicop»> (sec behind you) 15c "Eloc-Trick'' Push Bottoo ... 10a your ihutDO, and WRITES with WATER S°-SS; L<"X)NS. A bhvhtly colored bal: Great Hind Reading Myaterv Cds. 10c InklcssPen (wriuswlth watar) . lOc ihnt mKuiircs alxteen Inches lonit is Imiutjon Bed Bu«a lOa *t)r«h4a' ' your yoa dip. MaJcea Ita own Ink. Wrttea Thurston's UyaterTooj Trick Cds. 10c way, and. when rictlna aa yoa faahlofiablfl rtulat color. Better aod blown uQ in the usualui Fighting Rooatera, pair .... 10c air M» Bill - bwat Won't waab off cbaapar than rouscain pena. Write* a Eclcaaeo, the prnnau.v ^.u TVick Book -f t XOo f^ Cover the Spot Trick. a acl«n.no». lOe AmmalDtanca twlttT Uld Hthar. Any of tbaoa cbotee loec Mttar wttb ooa dJp in plain watar. alloon SOARING UPWARD, tho 3H- Carda start- X Ray Novelty 10c amoslngf rt. fool. liar, gromth, baby, No trooble— BO botber— fw moaa. A Inch proMller SPIN-NING AROUND AT A LIVELY RATE. The effect Is •'1, May Tr1.-k rencll lOc Olasa Watch Uiekan, t air. b«l: Satai^ Flrat. placMtra to naa. WHh Nkbel Plated «- H& ag~»--f jl flier ti.a: make* the yonniriters WILD WITH JOY. be ...... ,'± '" repeetaib" -r.dion cr uutdoori. Ah Immensei/ lnt*restina toy, Prloa 10a good Joke) MuldoMng Billiard ^11 THcIc pad at._ !n<. tSe £• ranlbU Holder 10 CtMTS, a for ZU _j

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Motor information you need to help you in your every day work is in i^v* «• principles—armature reaction —motor starting calculations—brake horsepower—selection and installation o( dynamo and motors—galvanometers—standard cells—current measurement — resistance measurement — voltmeters — watt- meters—watt hour meters—operation of dynamos—operation of motors, etc. No» 3 Con^sins SOO pages, 423 illustrations. Distribution systems—wires and wire calculations Inside, out- 1-1 J — H AW KINS aide and underground wiring—sign flashers—lightning protection—recaflers—storage battery systems, etc. No. 4 Contains 270 pages, 379 Uluslratlons. Altemstlni ELECTRICAL GUIDES ^ current principles alternating — current diagrams —the power factor—alternator principles—alternator con- These books place electricity at your finger ends. They cover every imaginable struction—windings, etc. subject, principle, theory, problem, trouble, and way of doing things electrically. 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You can't ask an electrical question that ers—relays—Ughtning protector apparatus—regulating devices Hawkins Guides can*t answer. —synchronous condensers—indicating devices—meters—power factor indicators—wave form measurement—switch boards, eto, M** Contains 316 pages, 379 illustrations. Alternating *'"• 7 Pocket-Size Flexible Covers ' current, wiring power stations—turbines; management, selection, location, erection, testing, running, care and repair—telephones, etc. The books are small enough to slip into your COat Contains What Electrical Men Say pocket—handsomely bound in flexible black covers. No. 8 332 pages, 436 illusfraUons. Telegraph ^' — simuit.aneous telegraphy You can carr>' each volume with until , and telephony you you have , , — wireless—elect nc bells— ^^ Helped Him Make Good mastered its contents. 3^500 pages of actual information electric lichtine—photometry, ett ^^ and 4,700 illustrations. ^A^nce you see these books and No *) Contains 322 pages. 627 Illustrations. EJec- ^ "It la only right for me to recom- put them into actual use' ou will never trie railways—electric locomotives—car light- again wont to be . ! ^ ing—trolley ^ mend hlBhly the Hawkins Guides, for without them. Try it at our expense. car operation—miacelJaneous applications— .^ motion they have b-^^n of the greatest assist- pictures—gas engine ignition—automobile self- ^r starters ance txt me in placing me in my pres- and lichling systems, electric vehicles etc. ent position as Superintendent of Con- ^Pftains 513 pages, 599 illustrations. 4No1VF* 10Av ^ itruction Department of one of Ohio's Elevators—cranes— pumps—air com- ^F largest Electrical Companies. I would SEND NO MONEY pressors—electrio heating — electric welding— *,^^ Tucn soldering like to see every man have a set of and brazing—industrial electro- ^^F «. ,*.-, • «#.' Hawkms Guides," It will coat you nothing to receive these books—to look lysis—electro plating—electro- therapeutic ^r AyDEL & CO. Geo. KJiecht. 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Y. nothing. contained the ^^ „J\ *?h?*ift n»'£w.°°*'?; ^T 10 electrical guides. Superintendent When you decide to keep them you only have to pay ^ ^.ri\V^" ^eS'l^'^ln^ ¥ou% Jl.OO down and remit the balance of J9.00 on the easy There are over 13,- a within seven days and to further "I am now lupcrlntendent of the payment of $1.00 a month till paid for. 500 croi?s refer- ^^ mail you $1 each month until paid. Dunnvill© Hydro - Electric Systems, Use this coupon to get the books. It will pay you ences. You find ^^ and Hawkins Guides were a great help many tlmea over. you want to me in holding down % responsible what ^^ signature position." to know In- ^^ W. E. Swartz, Dunnvllle, Ontario. stantly. THEO. AUDEL & CO. ^^^^ Occupation„ Wireless Operators "1 have worked wireless for tea 72 Fifth Ave. New York, N. Y. ^^ Business Address year*—but I wish I had tiiese books years ago, as they have saved me a great deal of trouble." H. Marshall- ^^r Residence Steamer M & B No. 2. 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