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Without the help of trained electricians on our battleships, in the army and in the thousands of manufacturing and transportation industries behind the fighting line the United States cannot hope to win the war. ]\Iore young men must be found and trained AT ONCE for the thousands of new positions in the electrical field. Send the coupon below for full particulars. Hundreds and thousands of Expert Electri- cians are giving up their positions to become soldiers. Their places must be filled—quickly. The work they have been doing cannot wait for their return. If you cannot fight at the front, it is your duty to prepare yourself NOW to help at home—not only with your hands but with a trained mind and a trained skill. The President says our production and efficiency must be doubled. He means YOU—your efficiency. Don't shirk your duty. Do NOW', for your country's sake, what you might not do for your own sake. Fit yourself for important, vitally essential work as an Expert Electrician. Learn NOW—at home—by Wonderful NEW SYSTEM

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Electrical Experimemiter 233 FULTON STREET, NEW YORK PuMisht by Experimenter Publishing Company, Inc. (H. Gernsljack, President; S. Gernsback, Treasurer^ 233 Fulton Street, New York

Vol.V Whole No. 51 CONTENTS FOR JULY, 1917 No. 3

...li..nt . ANTENNA OLD U. &. UATrLESUll-S TO THK FRONT C TL»T1N(^ RADIO LNITS WITH DUM.MV From a paintinB by deorRC Wall By Frank C. Perkins 186 LOCATING AND UESTKOYING SUBMARINES WITH A REU HOW RADIO BROUGHT THE NEWS TO THE FARM I.HJHT UAV 165 The story of Archie Banks 189 166 '. WIRELESS ON THE AMERICAN SUBMARINE CHASERS SEE^: '. HOW lyE'sUBMARINE CAN'Hif 'a SHIP'lf "nEVER' Cohen 190 Winfield Secor 167 By Samuel By H. "STICK DOES RADIANT MGIIT POSSESS WEIGHT?. By A. R. McPherson 168 AN IMPROVED BURGLAR AL.\RM UTILIZING THE WAR AND RADIO IN THE MOVIES...... 169 REL.W" By Albert H. Beiler 194 CONSTRUCTING '/,-T()S LIFTING MAGNET By J. Lwak 195 U S BATTLESHIPS TO RUN ON LAND By H. Gernsback 170 A RADIO-ACTIVITY MORE ABOUT THE "PERPETUAL" ELECTRIC CLOCK the" marvels ok v,'-;- 196 By Icrome S. Marcus— Part I 171 Bv Howard W. Lewis BACK TO THE DAVS OF VOLTA 172 HOWTOMAKEIT DEPARTMENT ' 199 173 AMATEIK AND EXPERIMENTAL RADIO RESEARCH—PART I. '.'.'.'.'. Raymond Francis Yates 201 LVt^^rMNG—HOW^TirPROTECT' yourself" i=^^^ "if! By By W. G. Whitman 174 EXPERIMENTAL CHEMISTRY—LESSON 14... By A. W. Wilsdon 203 THE SCIENCE OF SOUND • 176 WRINKLES, RECIPES AND FORMULAS. .Edited by S. Gernsback 204 SPEEDING UP VOTE OF CONGRESS BY ELECTRICITY 179 LATEST PATENTS DIGEST 208 ••H\M" TONES— SCIENTIST By Harlan A. Evi-leth 180 PHONEY PATENT CONTEST 209 1S2 OUESTION POX 210 20.000 VOLTS DIRECT CURRENT

War and the Inventor

N this great crisis, a word to our patriotic the way—the only way—to proceed : Remember first, inventors will not be amiss. As I have that the Government receives daily thousands of useless pointed out before, the average inventor is letters from inventors yours may be useless, no matter a poor business man and a worse salesrnan. what YOU think. Remember too that there is no greater its in- No matter how clever or how ingenious intoxicant than a newly born invention ; under straight, least he is, he will insist upon presenting his fluence you are in no condition to think story in the worst possible manner. As a of all sending your invention to Washington. I have rule he has labored for nights upon nights in solving an been intoxicated myself dozens of times in precisely this manner and I know whereof I speak. important problem ; every phase of the invention is so clear and lucid to him that he becomes irritable and angry First you should take your plan to a trusted friend if those about him do not at once grasp all the details. Or who is versed in mechanics or electricity. Invite crit- else, in his enthusiasm, he will sit down and taking a icism. Obtain expert opinion. Remember you don't piece of brown wrapping paper and a pencil, he will know it all—no one does. Edison says he is just begin- forthwith begin to write out a few often unintelligible ning to know a few Nothings. phrases, garnished with incomprehensible sketches, If the expert advice convinces you, that you really which are supposed to clearly explain liis invention. He have a worthy device, then and only then begin to think closes the missile by offering his device "free and gratis'' about Washington. Have someone typewrite vour idea to the Government, puts it in an envelope addrest to the in a neat and clear manner AND MAKE IT SHORT. Secretary of the Navy, and then mails the letter, think- Long explanations hurt your cause. Use the telegraphic ing that he has done a great patriotic act. Then if a style, just as if you had to pay for each word and don't long ominous silence follows, the inventor as a rule be- attempt to make your own drawing, unless you are comes embittered and hostile to the Government. thoroly familiar with drafting instruments. Find a Now, this is no exaggeration. As Editor of "Patent draftsman who will make a creditable drawing in China ink upon a liristol board. Then sign your name and Advice" I receive from twenty to thirty letters a day, to m be transmitted to the Government, if in my estimation address to BOTH description and drawing, and mail the the device is practical. And not two of these ideas are two FLAT. Don't roll either manuscript or drawing. submitted in a presentable or even an intelligent manner.- But use a piece of heavy stiff cardboard to keep the con- Penciled letters prevail and often the sender forgets to tents of your letter from being folded in the mails. If sign his name. And in Washington the War and Navy you do this I promise you a warm letter of thanks from Departments are deluged daily with just this sort of the official who reads your invention. mail, ninety-nine percent of which is discarded. And it Moreover, don't send your letter to your Congressman probably happens once in a while too, that the Govern- or to your Senator, as many misguided inventors are ment loses a really good idea simply because the one wont to do. At best it only delays it. Instead, address submitted was unintelligible and in consequence found it to either the Secretary of War. or to the Secretary its grave in a waste basket. of the Navy, all depending upon what subject your in- Now the man at his desk in Washington is human vention treats. Last but not least don't worry our offi- and consequently weak. Try as he may, he will pay more cials with torpedo or submarine catchers which depend attention to a neatly typed letter, than to a scrawly pen- upon magnets. The majority of ideas submitted are ciled note. A correctly drawn sketch will at least arouse based upon this popular delusion. Here are facts: If a passing interest, whereas a misshapen free-hand pen- you had an electromagnet that would attract one million cil design, will rarely fetch a spark of enthusiasm. ipounds (no such animal was ever built!) a steel torpedo The inventor would not dream of running to the War rushing by it at a distance of 20 feet would not be devi- Department in armsleeves. imkempt, unshaven and in a ated one inch from its course. For the largest electro- soiled and torn shirt. Ijut he insists on sending the magnet exerts practically no tangible force a few feet child of his brain just that way. away from its poles. If you have an idea that you think is worthy, this is H. GERNSBACK.

publication. special rate Is paid for norel exi>eriinenta THE ELECTRICAL EXPERIMENTER ta puhli'^tit on the Irlth nf each monUv at 2^.3 contrilmtlons are paid for on A Fultdti Slrwl. New York Tlitro art' 12 nuniliera per year Subscription price is J1.50 a good photoKraplis accompanyinp them are highly desirable, year In IT. 8. and pnsHi«sioiis Canada and foreign countries. $'.1.00 a year. D. S. coin as well as V. 8. stamps accrpted (no forelim coins or statnps) SIhrIc copies, 15 cents TTTE ET.EmiirAL EXPEIITMTTXTFR Monthly. Entered as second-class matter at nrdora should he each. A (laniple ropy will be spnt (tratts on request <'hcrk3 and money under Act of Congress of March 3, 1879. TlUe registered U. S. your the New York Post OJTlce. drai,vn to ordi'r of I't'IlMSIIINO CO . INC. If you chanKO THK KXI'KRIMKNTER Patent Omce (VpvrlKht. ll'l". bv E. P Co.. Inc.. New York. The content! of this address notify us promptly. order copies are not miscarried or lost. Br**" In (hat A magazine are copyrighted and must not be reproduced without giving full credit to the Indicates expiration. wrapper No coplei sent after expiration. publication.

All rommunlratlonB and contributions to this Journal should be addrcet to: Editor, ET.ErTRICAL EXPERIMENTER Is for sale at all newsstands in the United SUtea THE EI.ErTRICAL KXI'KRIMKNTEn. 2.?:^ Fulton Street. Ne* York Unaccepted con- THE at Brentano's. 37 Avenue de I'Opera. Pahs. trlbulloaa cannot be returned unleaa full return postage bas been Included. ALL accepted and Canada: also 163 164 THE ELECTRICAL EXPERIMENTER July. 1917

At Last! Electromagnetic waves of any length from sm incsmdescent lamp.

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MANUFACTURED BY DEFOREST RADIO TELEPHONE TYPE EJ2—PRICE, $32.00 AND TELEGRAPH COMPANY TYPE VC4—PRICE $20.00 NEW AUDION AMPLIFIER FOR VARIABLE CONDENSER INCREASING STRENGTH OF RE- NEW YORK CITY This Condenser is similar to our commercial type but is en- CEIVED SIGNALS 25 TIMES. Office and Factory Cable Address; closed in an oak cabinet. It has 35 semi-circular aluminvim It is not a detector in any form. 1391 SEDGWICK AVE. RADIOTEL, N. Y. plates. The maximum capacity is approximately .0OJ5 M. F.

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H. GERMSBC^CK EDITC7R H. W. 5ZZDR A550Z\UT£ EDITOR

Vol. V. Whole No. 51 July, 1917 Number 3

Locating and Destroying Subm arines with Red Light

A NEW method due to Yankee in- the high seas withwitli safety, so far as sub- or taste a submarine over a mile distant, ANEWgenuity and intended for locating marine attacks are concerned. so we are left only two of the senses submerged sub-sea boats at a con- As may be imagined, the experiment- remaining—the sense of the eye and that sideral)le range has recently been ers in this field are not willing to make of the ear. worked out. It has been described public the actual experiments, details The microphone enables us to hear less distinctly the engines of by a retired naval officer and appears to and results accomplished, but the fol- more or working have made a favorable impression on the lowing outline of the method now under the submarine when they are but this is not navy's experts. consideration will be of great interest at m.ore than slow speed, sufficient, as a submarine lying in wait If once it becomes possible to locate to the public. only turn the presence of an enemy submarine, Inasmuch as the great advantage of to torpedo a vessel needs to

Why Not Locate the Submerged, Yet Always Dangerous. Enemy Submarines by Continually Flashing a Powerful Red Searchllqht Beam Back and Forth Thru and Under the Water. Asks a Yankee Genius. Once a "Bulge" Is Spotted (Day or Night) in the Light Beam, the Observer on the Mast Signals That Fact to the Gun Crews. Consequence—as Soon as the Periscope Appears the Already Trained Guns Open Fire. The Spotting Range Is Over Two Miles, Day or Night.

then the greatest worry of cargo steam- the submarine over surface vessels is her engines over very slowly to main- ship captains will be over, for when the the fact that it is hidden from view, tain her depth below the surface. "sub's" location is spotted then the ves- if by some means the exact location A submarine vibrator operated by sel's gims will be trained on the spot. is made known to a vessel before she electricity has produced an echo from As soon as the under-watcr boat comes approaches within the danger range (2,- an iceberg two miles distant, but it is to the surface to take her sightings she 000 to 2,500 yards) of the submarine. doubtful if the system can be improved will be met with a hail of shot and shell. the menaced vessel can invariably es- to efficiency in the case of the submarine. The new method, holding great prom- cape. Now let us consider our remaining sense: ise for the destruction of the submarine In seeking methods to be employed sight. and its entire elimination as an efficient for certain purposes, inventors and ex- \\'hcn our ship approaches the danger the latter is main- weapon of warfare is now being per- perimenters frequently turn to the five 7onc of the submarine heading is nearly at fected, and it is probable that within senses when beginning the solution of taining a which a very few weeks vessels may navigate a baffling problem. We cannot feel, smell (Contiiiiird on f

166 THE ELECTRICAL EXPERIMENTER July. 1917 Cold Light

are accustomed to seeing the substitution, the intermittent flashes pro- luminous rays are concentrated in a ven.- electric or other source of light ducing the effect of a steady light. Each small point or space. The tungsten lamps design. WE i. e.. with- lamp is in consequence lighted for so short employed are of Dussaud's own with unfeeling senses, out stopping to realize for one a time period that the infinitesimal amount Some of them are only 0.8 to 1.6 inches of heat developed is quickly dissipated. in radius. Groups of three are used in moment that—while it is undeni- ably true that the modern electric light is The cooling interval is about twice that of some models. They are successively flashed lens, without a masterpiece of scientific attainment, the light interval. The lamps, moreover, in the focus of a condensing thanks to Edison and other investigators can in this way be operated on 3 to 4 times breaking down the filament or blackening we are actually paying many times what the normal voltage, vastly increasing the the bulb. Indeed, it is said that the re- of each filament identical with those we should expend for this human com- efficiency and illumination sults produced are is that has sue- ten times more fort. Think for one moment that only thereby. It said Dussaud obtained with an electric arc intense. S per cent of the electrical energ\- put into a modern gas-filled, tungsten filament, in- For motion picture projection machines candescent electric lamp is realized as use- the new cold light possesses wonderful merits, enabling the operator to run the ful light : the balance of the energy is paid for and uselessly dissipated in the form of film off as slowly as desired, and even to heat and other radiation. stop the film for examination when necessary. Dussaud, scientist, has projected mo- The fire-fly is one of the greatest and on screen 15 feet square with absorbing wonders of all Nature. Why? tion pictures a electrical energy consumption of 150 —because he knows how to produce prac- an watts, compared to the 5 to 10 kilowatt tically a cold light. The illumination engineers of today are studying the problem (5,000 to 10,000 watts) arcs now used. And cold light machine, complete with gen- with all the resources at their command. the carried easily in the hand. There ought to be—there must be a way in erator, could be this rapid dissipation of heat, it which to convert all or nearly all of the Due to emploj- celluloid instead electrical energy' into useful light The becomes possible to for ordinary lantern slides electric motor converts electrical energj- of glass plates igniting the celluloid or into mechanical energy with an over-all with no danger of it shrivel up. Dussaud has efficiency of 90 to 98 per cent. Suppose of causing to his cold light it will we had perfected an electric motor with an prophesied that with be possible to use celluloid films ^ of an efficiency of but 3 per cent : how many 1 inch in size instead of glass motors do you think there would be in inch by inches. The celluloid can use? Yet we are content, at least unti plates 3H by 4

Above—The Microscopic Projection of a Above — Complete Dussaud Experimentaf "Cold Light" Beam as Devised by Prof. Dus- "Cold Light" with Generator and Current saud of France. Measuring Meters. be cut into long strips, perforated along we know more about the subject, to use the edges so that it can be printed mechan- electric lights with this almost unbelievably ically, as in making moving picture posi- low conversion efliciency. tives. Indeed, he claims that a single One of the nearest approaches to man- operator can make twenty-five thousand tiny photo- made cold light is that of Professor C. F. celluloid prints a day. These Dussaud, French scientist and investigator. graphs can be made by anj' amateur at a The accompanying views show some of the cost of not more than a cent, and can be successful apparatus devised by him, also projected on the screen by means of small, their applications. Dussaud has evolved a low-priced projectors. very ingenious arrangement, which, altho By utilizing the marvelous cold light not giving a true heatless light, yet pro- auto-chrome plates can be projected, which induces light with a negligible quantity of otherwise suffer when exposed to the arc. Powerful heat. tense heat of the electric The elementary principle upon which this lights can be concentrated upon parts of the danger of scorching so-called cold light is based is that of im- human body without foreign bodies pressing at sufficiently close and intermit- them, with the result that the muscles. tent intervals an excess voltage of several can be located very readily in times the normal value to each lamp. To The cold light lends itself admirably to incon- accomplish this a number of incandescent the photographing of interiors. The Projector Top Center View—A "Cold Light" veniences attending the use of ordinarj- . lamps are arranged in a circle on a of Type Intended for Use by the Dussaud well known. rotatable disc as shown herewith. This disc Firemen and for Military Purposes. Center magnesium flash powder are it possible to may be rotated by hand or by an electric ^Rear View of "Cold Light" Machine. Powerful cold lights render Lower Center—A Three-Lamp Projecting make very brief exposures without filling motor. The lamps have metal bases and "Cold Light" Apparatus. the room with smoke a metal brush contact is caused to press the atmosphere of against one base at a time. All the lamp and fumes. sim- bases have one of their poles connected ceeded in obtaining 250 to 800 C.P. of cold \\ith a small electric battery and a range can to a common return contact, made in the light for several hours from a bank of 16 ple lens, a beacon light of long an apparatus form of a ring at the back of the disc, lamps rated normally at only 25 to 80 C.P. be cheaplv produced. Such small sailing against which a second metallic brush with an energy in-put of 50 to 160 watts. will be found serviceable on by soldiers. It is easy makes contact. As seen it now becomes Professor Dussaud employs an optical boats as well as telegraph possible to rapidly switch one lamp after system with his lamps, in other words, enough with such a device to of the the other into circuit, consecutively. The either lenses or mirrors. The result is optically for great distances. One projection of persistence of vision of the retina of the that while the heat effect of the electric views shows tlie microscopic human eye defies the detection of the lamp current is dissipated over a great area, the cold light. July. 1917 THE ELECTRICAL EXPERIMENTER 167

How the Submarine Can Hit a Ship It Never Sees By H. WINFIELD SECOR

is 1 !•; German submarine has finally requires to sound the death knell of the at the receiving station, and which set Tl lifcome a most menacing factor in proud merchantman. into vibration by the sound waves or vibra- llic great world-war and now pre- And sound it he does, for as soon as tions in the water. Prof. Fessenden has sents a tirst-class i)rol)letn to all he has the necessary data on your status succeeded in telephoning several miles by the would-l)e and master inventors and position, he at once transmits it thru means of such sound vibrations propagated — electrical, mechanical —and fourth-dimen- the water by powerful sound waves to thru water. Thus we see how it is not sion. Kememher reading now and then in one or more submerged sub-sea lighters only feasible, but entirely possible for a the daily papers how "another" merchant lying in the path of the on-coming steamer. submarine to torpedo a ship without ever vessel was torpedoed and the officers saw Knowing the location, direction and speed having seen it. no submarine' Sank in 10 miiuitcs and of the unsuspecting commerce boat, the (The above-mentioned sound wave sub- crew left in the water to lloat ashore or hidden submarine (or submarines) can dis- sea telegraph apparatus was fully described, possibly to be picked up by a patrol boat. charge a torpedo sufficiently accurate to with photographs, in our August, 1915, Yes, there have been a lot of such cases spell the finish of the "barred zone" prey. and February, 1916, issues.)

The Latest Reports Regarding Submarine Activities Frequently State that the Ship Was Torpedoed by an "Unseen" Sub-sea War-vessel. This Can Easily Be True for, by Utilizing Telegraphic Sound-waves Propagated Thru Water (Fessenden System), a Relatively Distant "Range-finding" Submarine Can Signal Her Hidden Allies as to the Position and Course of the Enemy. Thus the Submarine That Frres the Fatal Torpedo Need Never Show Its Periscope.

as this and even more mysterious ones. The illustration shows this remarkable For instance there is the case where the maneuver in a grafic manner. The mer- ELECTRICAL TREATMENT OF ship's lookout remembers having seen an chantman may even fire on the periscope BRITISH WOUNDED. enemy submarine several miles ofif—much of the distant submarine, but as aforemen- too far to be within torpedo range. More- tioned the chances of hitting it at a range In a recent number of the "Lancet," Dr. over, nothing more had been seen of the of 1^2 to 2 miles are very slim. Besides, \V. J. Turrell describes various applica- enemy after the first sighting, but sud- the spotting submarine may have been tions of electro-therapy at the Radcliflfe denly—a terrible explosion fairly lifted the watching the steamer for some minutes Infirmary, Oxford, England. One inter- boat out of the sea—torpedoed? Sure as before the latter's look-out spies the cun- esting point is the treatment of unclean guns? But how? asks every(5ne, from Cap- ningly disguised and mottled periscope. woimds by ionization, produced either by application of salt solutions traversed tain down : yes, how ? and in broad day- At the first shot from the steamship's gun the

light ! crew the submarine may disappear. Con- by an electric current, or by means of ultra- That's the question—and it now seems sider that the U-boat commander has the violet rays. .\s is well known, electric that there is an answer. Possibly the range of the enemy; he at once dispatches currents are now much used in treating reader has guest it by looking at the ac- the data by sub-sea telegraphy or tele- certain varieties of rheumatism. companying illustration. At any rate here's phony, so that other U-boats lying sub- Of considerable importance is the appli- a new aspect, and what is more, a thoroly merged or awash at the surface, will re- cation of mild electric "shock" to stimulate

practical one of the science of submarin- ceive the information on their sound wave the \ olimtary movements ; the treatment is ing. Let us admit that the oflicers on apparatus. specially efiicacious in those cases of nerve the merchant ship spot a periscope sev- All this may sound somewhat mytho- shock where the patient is under the de- eral miles away, or even a mile and a half logical—l)ut it is not. Our own sub-sea lusion that he has lost the power of his away. That's an almost impossible target fighters and war vessels are all equipt limbs. to hit with any kind of gun and the with similar instruments. They are based However, the application of electric chances are the submarine couldn't shoot upon the researches of Prof. Reginald methods to cases of "shell-shock" calls for a torpedo once in ten times to hit the mer- A. Fessenden, the well-known American discretion. In some such cases the pa- chantman at such a range. inventor and scientist, and involve the prin- tient is not at all benefited and, indeed, However, the Clcrman sub-sea boat com- ciple that water will transmit sound waves exhibits "electrophobia." m.inder doesn't have to worry about sink- remarkably well. To set up such sound Currents are also a valuable means of ing the freighter with a torpedo from his waves of sufficient power to carry sev- testing the action of various muscles and submarine. Not at all. Give him a few eral miles (in tests, this method of com- the powers of sensation, and in producing minutes to draw a bead on your position munication has worked up to 20 miles) a movements which break down internal ad- and your speed, as well as the course, with special heavy diafram is employed, which hesions or the binding of scar-tissue. The his periscope and range-i'mding instru- is caused to vibrate rapidly by electro- static machine is considered specially use- ments. That is all the information he magnetic means. A similar diafram is used ful in this direction. 168 THE ELECTRICAL EXPERIMENTER July. 1917 Does Radiant Light Possess Weight? By A. R. Mcpherson

study of light presents some very conception that the ether, instead of being to the theories of Einstein and Norstrom, THEinteresting facts in regard to that some mysterious form of non-matter, as there should be a real influence of gravita- mysterious force of Nature, which' generally believed, is actually the lightest tion on light. It is asserted that the spec- permits man to view the visible ob- and the simplest of the elements, and a trum lines of two light-rays originating in jects of this material world, and al- definite form of matter. He believes it to be gravitation fields of different strengths are tho we are still in the dark, so to speak, as one of the inactive gases of the Argon fam- shifted relatively to each other. As Frem- to the true nature of light, much progress ily of elements and he assigns to it the lech has now shown, the shifting is very its is is being made which will perhaps, even in position 'X,' in the zero group of his re- well e-xplained, so far as amount con- the present generation, reveal the facts vised periodic arrangement of the elements. cerned, by Einstein's theorj-. An influence concerning light. The first theory advanced The atomic weight of the ether he concludes of an impulse proceeding from the sun, on Is"ISgM"^ Material Substance?

POSITION OF LIGHT BEAM LIGHT RAYS I.. W (normal -NO magnet) HICOL PRISM

POWERFUL MAGNET POLES OEFIECTEO^-, RAY CAUSED ! theory of "Lighi" wiiich says , BY MAGNET thai Ligh-t is caused hy electrically charged egg-shaped particles revolving at enormous vel- Certain speciritm lines are aliered in position ocity about their shorter axes. (Zeeman effect) by powerful ma-gne-tic field.

CROOKE'S RADIOMETER LIGHT RAVS

"ALPHA RAYS--^VJg|^^'^'''B ETA HAYS" ^tlOCITY= (velocity- 2O.O0OMILES RADIUM MORE in«M loaoo. PCRSECOND) MILCS PtRSECONt

Fremlech as wellas Einstein and That "Li^fmaybe a material Norstrom. claim thai: the suhstaitce, having weight. Seems Spectrum lines of two light rays possiile, as it has been prawn originating la gravitation fielas The pressure cflight The total "Light that the above Hadium rays of different sfrenpibs FiandFz has been measured pressure' on the are actually streams oflittle are shifted relatively to each oilier It TVill spin the vanes earth has been cal- bodies having amass tvrice tending to shcmrlhai hghi hasweight. of the radiometer culated at 70.000 tons that of the Hydrogen atom

as to the nature of light was the mate- to be one-millionth of that of hydrogen and shifting, cannot be the cause ; for in this rialistic theory, which involved the idea that its atoms consequently travel with enormous case, single lines would be shifted in differ- light was composed of material farticles of velocities. This extreme velocity explains ent degrees. But the measurements show matter. This theory was rejected years ago, the all-pervading character of the sub- that the shifting of the lines, both in amount but like tlie alchemists' dreams of the trans- stance." and direction, is the same for all, as Ein- mutation of matter, which it seems is now Prof. T. J. J. See, a scientist whose re- stein's theory of the influence of gravitation becoming a reality, so this materialistic searches are known thruout the world, re- requires. The shifting of the lines calcu- theory is again coming into favor. cently made public —the following statement lated with Einstein's formula agrees re- The present generally accepted theory in regard to light : "Tlie whole tlieory of markably well with the average observed states that light is identical with electro- ether is abandoned as having no real exist- values. The influence of gravitation on magnetic disturbances, such as are generated ence, light being caused by electrically light may now" be regarded as partially by oscillating electric currents or moving charged particles, shaped like eggs, revolv- proved, and thus it may also be inferred

magnets ; but this must presuppose the ex- ing about their shorter axes." that light possesses zi'eight. istence of an imaginary medium called It would thus seem that there is consid- From the above facts it may be demon- ether, which is supposed to penade all erable difference of opinion about the na- strated and must also be proven that li.ght space, and is in the interior of all bodies of ture of light, and the writer has endeavored exerts pressure, since it is a material sub- whatever nature. It is thin, elastic, and to gather together some of the leading stance possessing weight. This peculiar capable of transmitting vibrations with facts and theories which tend to throw some truth was proven mathematically as early enormous velocity. Every luminous bod}' is "light" on the subject. as 1873 by Maxwell, tho it was applied in a state of vibration and communicates If it can be proven that light has weight. then and still is to a certain extent in sup- vibrations to the surrounding ether. This, it must necessarily follow that it possesses port of the clectro-magiietie leaz-e theory. in short, is the electro-magnetic etlier theory material form and properties. Xo influence In 1901, Peter Lelidew actually proved and which has been evolved in recent years. of any form of attraction on light had been measured the meehanieal pressure of light. It is the belief of many, however, that noticed until about twent\- years ago, when The pressure discovered was small, of ether, to exist at all, must be in a material Zeeman showed that a powerful magnet vis- course, but the minuteness of a thing is form such as a gas, in order to harmonize ibly altered the position of certain lines in often an inverse measure of its importance, with natural laws. To quote from "Xew the spectrum. as this light pressure has been found ade-

Knowledge" : ".Mendelieff, the Dean of Xow it appears that gravitation has a quate to explain some of the earth's greatest chemical science, has recently originated the similar, tho not the same effect. According {Continued on page 215) ELECTRICAL EXPERIMENTER 169 July. 1917 THE War and Radio In the Movies

group of vehenieiilly denounces her native land. hero of the realistic Bhiebird crimes, learns of the plans of a to be connected Paul Strong, perceiving in Mary's posi- TllF. "Treason," is a (govern- criminals, who are supposed photoplav— blow- murders, in whose power the tion an opportunity to strike a telling ment telegrapher in the service of a with the and held. to the "enemy," accordingly outfits a wire- mvthical European country at war girl who he loves was formerly contrivance whereby Marv, selected to The enemy having "captured" New York less telephone with its neik'lilfor. He is "enemy," in Greater \"itagraph's preparedness thru her close association with the po to the front, and this arouses the jealousy City, "Womanhood," Harry Morey, who can inform him of their plans without in- chief, who reuards it as a personal spectacle of his left lower part of Paul Strong, Director of curring their suspicions. ( See and affront. I'ettrus distinguishes himsell at the plays the proceeds to evolve a center photos.) The copper gutters on the front as a telc^;^aphcr, and is iinalided Energies, U. S. .\., of the Woolworth Building are used of jiromotion, that plan by which he can be appraised of their roof home. IK- finds, instead radio- movements and act accordingly. as antenna. Mary employs a pocket he is degraded to the position of messenser. jilione instrument^ which she connects with His chief has tampered witli a telegram, the improvised antenna, thru a secret switch, orderiuK liim to spare I'cttrus as mucli as cleverly hidden in the brass scroll work of possible. an electrolier on the side wall. He feels deeply the neplect of his country, and confides his feeliuKS to his friendv the tobacconist, who in reality is a "spy." The ODDLY IDENTIFIED BY RADIO. enemy (top man sends information to the American naval officers are highly con- view) bv means of wireless ai)paratus amused over a recent "wireless mmance" rooms, (extreme cealed ill a trunk in his cnniiccted with an American destroyer. The Fettrus' re- rijjht plioto). He works upon story well exemplifies traditionary sea cau- finally persuades liim to sentment until he tion and hangs on the fact that by reason the home of the steal the new code from of two Americans having been roommates Secret Service, with wliose Head of" the at St. John's College at .'\nnapolis years is in love. No sooner has daughter I'cttrus ago, information was confirmed at sea that would give he done so, than he repents, and otherwise would have remained doubtful. to undo his act. anything One man is a civilian doctor, who has The Head of the Secret Service has been

Here You Have a Chance to See a Spy's "Trunl<" Radio Apparatus at Work. An Ab- sorbing IVtoment from the IVIaster Photo- play—"Treason."

to watching the tobacconist, whom he knows taken an important post in Great Britain, spv. questions Pettrus, who be a He now the other is a paymaster in the . navy. Secret finally confesses. The Head of the Two days before the destroyers sailed from code. Service helps him to recover the the United States these old friends ate a which There is a thrillini; automobile chase, farewell dinner. The doctor was to sail the side of a ends in a terrific smash o\er by a liner, but was ignorant of the ship's killed, and Pettrus cliff. The tobacconist is name and date of sailing. The paymaster he re- seriously injured. In the hospital, was under orders to join his destroyer. Head, who promises turns tlie code to the When several days at sea the destroyer secret lietween tlien-i. that his act shall be a got into distant connection one night with Chief has lieen The woman with whom his a certain vessel, and made a code inquiry of finds the doctored tele- on terms intimacy as to the vessel's position, course, and speed. for neglect, exposes gram, and in revenge No direct reply was made, the vessel fear- the of the Government the Chief to Head ing a submarine trick and the possibility department. delayed reward telegraph The of a stolen codebook. Instead of answer- Pettrus' services arrives, and the spite for ing a demand was made to the destroyer: Center:— Stirring Scene from "Trea- work of his Chief is revealed. Top A in code." the Great Photoplay of War. Radio and "Give the name of your ship Universal serial "The V'oice on the son." The Love. Center Scene:— A Moment from Uni- The destroyer complied. Wire" is concerned with a series of mur- versal's—"The Voice on the Wire." Lower Energies. Even this was not enough. A second ders, committed in the same way, by an Center:— Paul Strong, Director of "Womanhood," Receiving a Re- wireless was sent out : "What is the name attack on the victim over his heart which U. S. A., in port from His Sweetheart i the Enemy's of your paymaster who is the friend of leaves a bruise the size of a human thumb. Stronghold (Extreme Left) Via Radio." this shipr" Dr. , a passenger aboard No other clue is left except a message Irom Then the paymaster of the destrover a mysterious voice spoken over a discon- by was called into the wireless cabin and asked nected electric wire, which warns the vic- His sweetheart, Marv \\'ard, played . re- Prince if he knew Dr. "Sure." he tim of his end, and exults over the detec- Alice lovce, is also the object of was my best pal. \\ e were Dario's enamouration. Count Dario is one plied. 'He tives, as each time they fail to circumvent dinner to- invading host and roommates at college, and had it. In the eleventh episode, a strange inven- of the commanders of the I Where tlie mili- gether two nights before sailed. tion is introduced. This is a material de- the son of Marshal Prince Dario. Ruri- IS he?" velopment of the science of mental tele- taristic Commander-in-Chief of the The destroyer sent out another radio. pathy. (In the "movies," they do it!) By tanians, the name given t!ie "encni\-." is saying: "Paymaster . the doctor's a wireless arrangement, the mind in control Thru Count Dario's influence, Mary invader's headquar- oldest friend." can communicate with the mind it inllii- offered a position in the this corroborative statement the w-hich is located in the Woolworth After ences, and the machine is made to register ters course, this an oppor- vessel at last gave her position, the thought. By its use (central view here Building. Mary seeing in accepts, and and speed. shown) the investigator wlio is tracing the tunity to serve her country, 170 THE ELECTRICAL EXPERIMENTER July. 1917

U. S. Battleships to Run on Land ByH. GERNSBACK EVERY war brings out a host of paralleling tracks, under a ship. This car, hind her mine fields and bides her time. fantastic as well as ridiculous new after the ship was made fast to it in a But the U. S. navy has a number o£ inventions which are supposed to suitable manner, was then to be drawn over- battleships of the pre-dreadnought type, annihilate tlie enemy. Most of land—over the present Panama Canal good ships as yet, but obsolete as first- these wild-cat schemes are of course route—by powerful locomotives. line ships. I refer to ships of the Ore- as impractical as they are fantastic, and Lately other plans have appeared show- gon, lo'ii'a, Illinois, Kentucky, Massachu- while they look good on paper, the devices ing battleships running thru cities and over setts, Indiana class. These ships are fully do not stand up in practise, either because equipt now, have good crews and good of inherent defects or because science and guns. But the chances are that ten years technic have not progrest sufficiently to from now they will be used as targets do justice to the device. or otherwise will be relegated to the scrap- Thus a submarine invented by no less heap. So why not send these ships to the a genius than Robert Fulton, propelled by front? Briefly, the idea is this: several men and which was actually run Let us send these ships, men, guns and under water, was sanctioned by Xapoleon, all, to France. In the holds of the ves- the inventors hoping to sink the blockading sels we pack channel irons and T. as well English fleet. The submarine failed miser- as I steel beams, cut to the right length ably, to Napoleon's utter disgust. Never- before sailing. These pieces are fashioned theless the failure was not due to the much after the structural toy steel pieces principle being inherently wrong. Rather —^jou can make almost anything out of science had not progrest sufficiently to them. the make submarine a success one hun- When our battleship arrives in France. dred years ago. if Napoleon, he were to it is put immediately into dry dock, and come back today, would certainly experi- the crew at once proceeds to make the ence radical a change of mind, as to the wheels from the channel steel. These huge success of the submarine. wheels measuring over 50 to 60 feet in In the same manner, when John Ericsson height, are made on the plan of a Ferris constructed the "Monitor" in 1862, he was wheel, light but strong. Of course to sus- met with a good deal of ridicule—at first. tain a weight of 10.000 tons or more, a No one believed that his steel "cheese- set of single wheels won't do. Rather each box on a raft," vessel war could do much wheel is fashioned of a number of wheels damage, or even give a good account of from five upwards, paralleling each other, itself, let alone winning a battle. The world as graphically shown on our front cover, knew different after the "Monitor" defeated and the accompanying illustration. These the famous "Merrimac." separate wheels are bolted or riveted to- Makeshifts have been used in every war, gether by means of steel "I" beams run- and every important battle has them. ning over the circumference of the sepa- Sornetimes these makeshifts actually prove rate wheels. The latter are strengthened decisive in a battle, perhaps for the simple by additional cross-truss work, as seen in reason, that insofar as they usually con- illustration. Thus a very light, as well tain the element of surprise, the enemv, not as powerful wide wheel is formed. With being prepared for the unusual onslaught a little previous drilling, the crew should is defeated. be able to construct the Perhaps the most famous necessary six wheels in less ***** AAA A A A A A /> A instance where a big battle than one week—yes, it can was won with a makeshift be done providing the ; was the Battle of the Mame, pieces are cut to the right in 1914. No more impos- dimensions at home. sible or ridiculous weapon Next the thirteen inch hol- ^ \ * * * 4 than an ordinary taxicab low steel shaft is consid- could be imagined to launch ered. This, of course, has a modern army, equipt with been brought from America the world's best artillery. too. The hollow shaft, is Nevertheless, when the de- advised, first because it fender of Paris, General weighs less, and second be- Gallieni, requisitioned every cause such shafts are equally Paris taxicab, and flung as strong as solid ones, these thousands of squeaky \\ ithin a reasonable propor-

vehicles, w h i c h had never tion. been designed for such work, The two wheels at the against the German hordes, stern are "idlers," the same V 'r yi V vW they simply had to give way ; as the front wheels on an and the taxicabs won. One of automobile. No power is the world's greatest retreats Putting Wheels on Our Battleships and How It Is Accomplisht. The Wheels applied to them, they simply was mainly due to these Here Shown Are Fashioned of Angle and I Steel Beams, on the Plan of Structural rotate on the shaft, extend- peaceful fare-eaters. Per- Steel Toys. Such Wheels Are Tremendously Strong. Slow Running Electric I'nsr from one wheel tn the Motors Coupled to the Steel Shafts Drive the New Monster Over Land. haps taxicabs will never be other dear thru the ship used again in such a man- The two small center ner, but at any rate they did their full duty the houses, but no one volunteered to show wheels are also idlers. They serve to take once. The experiment proved worth while. how it might be accomplisht. A battle- up undue shocks, which might break the ship Therefore when I propose to run battleship weighs anywhere from 10,000 tons in two, when negotiating difficult terrain. ships over land, I am fully aware of the upwards—quite a respectable weight. How The two front (bow) wheels are the ridicule I will be subject to. I am also then can we run such a monster on land ? ''drivers". Thej' are bolted solid to the aware of all the objections that will be How can it be propelled ? shafts, two of the latter being used as cited against the fantastic-appearing plan. Now that we are at .var, our first duty will become apparent at once. Our illus- Nevertheless, I insist that the idea is not is to help our allies, and to help them tration shows that the two shafts revolve half as impractical as it may appear at quickly. The time is too short to build in a common bearing ( which might be an first. And at any rate I believe I have new colossal war engines which could be old reconstructed gun barrel). Each shaft found a way showing how it may be done used at the front at once. Our army will in turn is directly coupled to a slow-run- in a simple manner. I give the idea to the not be fully ready till a year from now. ning electric motor armature, as clearly country for what it is worth. Our navy cannot help very much on sea. shown. And this, by the way. is the much 1 do not claim to be the originator of For if the British, French and Russian discust electrical drive, adopted in our the idea to run battleships or other ships navies, which are at least four times as latest monster battle cruisers, now being over land. That idea is old already. Twen- powerful as the German navy, cannot de- constructed. From this it becomes ap- ty-five years ago there was published in a stroy the latter, the addition of our own parent how the land battleship is propelled German weekly an idea to run a power- navy will not matter much one way or an- overland in a simple and practical man- ful car, moving over a dozen closely spaced other. The German navy simply stays be- (Conlinued on pane 216) —

171 July, 1917 THE ELECTRICAL EXPERIMENTER The Marvels of Radio-Activity

By JEROME S. MARCUS, B. Sc. (Ch. E.)

Fint Paper of a New Series discharge electrified bodies, produce phos- Polonium is an element, but it accompanies is separated siilijfct of Radio-activity deals, phorescence in certain otiier bodies, and the Bismuth in the ore, and THEnot only witli Kadiiim as many lic- penetrate many things that ordinary light from it. discovery of these substances was licvc, liiit with a wliole class of snh- would not. Fig. 1. (Experiments on these The Debicrne dis- stances, the licst examples of which points will be given later.) These rays made in 1898 and in 1899, M. material which are Radium, L'raninm. Thorium, were named after their discoverer, "Bec- covered another radio-active follows the Actinium, and the chemical compounds of querel rays." It was also found that in he called "Actinium," and which and seems to be these substances. Hadio-iUtnily is the name carrying these ray-emitting ^ub^tiuices iron in the pitchblende connected w i t li given to the prop- ~' the' Thorium. erty which these J" suhstances h a v e It has been re.-ont of giving off or shown by emitting certain investigators that 1 1 sub- radiations spon- almost a nature taneously, these stances in are more or less rays having the '-i. ^ power to pene- radio-ac- trate thru matter tive.. Among these are freshly which is opaciue fallen rain or to ordinary light. snow, many History. spring waters, Shortly after etc. From this, the idea has been the discovery of that X-rays and their advanced properties by radio-activity i s certain Professor Ront- due to radiations from gen in 1895, many students of the sun itself. sup- physics began to These are jiosed be con- investigate the to nected w i t h the different p h o s - Gold Bar, About the Size of an Ordinary Building Brick. Worth $18,263.53. Tube of Radium the appearance of the phorescent bodies Size of a Match. Worth $18,000.00 (150 Milligrams at $120.00 Per Milligram). Photographed m the to ascertain Mint, at Denver, to Show Relative Value of Gold to Radium. Aurora Borealis and other phe- \v h e t h e r they would or not emit rays of the same char- around in one's pocket, burns which are nomena of atmospheric electricity. In the acter. Professor Henri Becquerel, a Paris very hard to heal are caused, known as spring of 1903, Professor J. J. Thomson physicist, discovered in 1896 that the com- ''Becquerel burns." discovered that waters from deep wells con- pounds of Uranium which had a phosphor- Investigation of these radiations w'cre tained a certain gas which was radio-active, substances are being found which escence (that is, they would glow in the dark immediately taken up, especially by E. and other after exposure to daylight) would weakly Rutherford, then a student in the laboratory also possess the power of radio-activity. « « * affect a photographic plate. He then found of J. J. (now Sir) Thomson at Cambridge, that salts of Uranium which were not phos- England. Their properties will be dis- Becquerel showed that the rays from phorescent also affected a plate, thus show- cust later. Uranium, like the X-rays, were capable of electrified body, when ing that it was the element Uranium which Mme. Curie, of Paris, made a system- discharging an atic investigation of a large number of charged either positively or negatively. substances to test whether they possest (Experiment—A gold leaf electroscope is the same rays as Uranium. At about the charged by touching to any source of static same time, in 1898, she and Professor electricity, e. g., a glass rod rubbed with Schmidt discovered that Thorium and its silk. An Uranium compound—any salt compounds were radioactive. Mme. Curie and her husband then began an exhaustive investigation of the Uranium compounds, and found that the activity was an atomic property, i.e.. it was propor- tional to the amount of Uranium present. While working on this basis with pitchblende, an ore from Joachimsthal, Austria, which contains Uranium, she found that the activity was four or five times greater than it should be. This led her to the conclusion that there must be something else with stronger properties than the Uranium. The Austrian Government placed a large amount of the ore at her disposal, and she Remarkable Photograph of the "Alpha" Rays of the Ra- set about separating the ex- dium Emanation. By C. T. R Wilson. tremely small amoimt of this then unknown substance. Her efforts W'cre purchased from a chemical house, the aii- experi- finally rewarded by the isolation of "Polo- thor uses Uranyl chlorid in his nium" and a substance of such intense ray- ments—is then brought near the knob. collapse. (Fig. 1.1 Top: Discharging an Electroscope by Ra- giving power that she termed it "Radium." The leaves are seen to dium. Lower Illustration Shows a "Radium Riiduim bromide has about two million times This property of radio-active substances is Light" Which Will Give Sufficient Illumina- for the the activity of Uranium. used as a delicate quantitative test tion to Read By. Radium has been found to he an element amount and intensity of radiation. .\ spe- for work possest the peculiar ray-emitting property. of defmite atomic weiglit, and accompanies cial electroscope has been devised research, the rate of collapsing It was then found that these rays or the Barium which is separated from the in Radium radiations of Uranium, like X-rays, would pitchblende. It is not proved as yet whether {Conlinucd on page 207) 172 THE ELECTRICAL EXPERIMENTER July, 1917 Back to the Days of '^Volta''

VOLTA, inventor of the first electric knowledge, had him write essays on elec- dium production companies employ this batter}-, after whom the standard tricity for the great men of the day. as method in testing their products. Fig. 1 also International unit of electrical pres- people in general knew very little about this shows various plate condensers, invented sure—the 'olt—is named, was one mysterious force at that early period. by \'olta. of the early, most brilliant and inde- The first formal scientific papers of \'oIta While professor of physics at Pavia, he fatigable workers in the realm of pure elec- were issued in his 24th year and fourteen conducted experiments which led to the trical science. He was born in Como, Italy, years later there appeared his clcctroplwrus discover)- of the I'oltaic pile. One of the Feb. IS, 1745, in a house which had been the (see illustration. Fig. 1.) followed by his accompanying illustrations. Fig. 4, shows homestead of the Volta family for over chctroscofc. The photographs here repro- one of the most remarkable historic docu- 3(X) years. Paradoxical as it may seem, duced show the now historic apparatus ments extant—the original letter, written in true genius is often linked with less brilliant built and used by \'olta in his laboratorv. French, of Alessandro \'olta addrest to the

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FIG.2

Fig. 1—Alessandro Volta, Dean of the Early Electrical Inventors Con- ducted Hundreds of Experiments witti Static Electricity. This Photo Shows Several of the Original Apparatus— Disk Condenser, Electro- scope. Etc.,— Used by Him. Fig. 2—Static Electric Apparatus which Belonged to Volta. The Appa- ratus on the Right Served to Produce a Static Spark by the Friction on a Strip of Parchment. As It Was Rapidly Reeled Up. Fig. 3—Volta's Original Apparatus: At Right— Device for Igniting Mix- ture of Hydrogen and Oxygen by a Static Spark. Left— Instrument for Demonstrating Electric Theory of Hail. Fig. 4—The Highly Prized Original Letter Written by Volta to the Royal Society of London Describing His First Battery—the "Voltaic Pile."

traits of character, and as a child we are Fig. 1 shows a variety of electro-static Societe Royale de Londres describing his told that Alessandro \'olta was very back- apparatus, including a static electric charg- new electric battery (\'oltaic pile), consist- ward. Even to the point that he could only ing device—the electrophorus, at extreme ing of alternate zinc and copper discs sepa- speak one word "Xo," when he had reached left, and the detector of static charges—the rated by dampened blotter paper sheets. his fourth birthday. electroscope at extreme right. Both of these This formed the basis of present-day elec- But, like many other great scholars of devices are still in use in electrical labora- tric batteries. There is no doubt that mod- the world, he suddenly developed a great tories where the elements of pure science ern electricity really starts with this famous affinity for philosoi)hy and became an are studied. Besides, the electricians of to- letter. For it was ^'olta's battery that pro- earnest student of scientific subjects, espe- day have found many practical applications duced the very first electric galvanic mark. cially the natural wonders of nature—par- for the electroscope, never even dreamed of It was \'olta who led the first galvanic cur- ticularly electricity. When he was 17 years by the illustrious \'olta. One important rent thru a wire. And it was his battery old he had won prizes in philosophy and at commercial and highly important applica- that produced for the first time useful 18, the famous Abbe Xolet. strongly im- tion of the sensitive electroscope is in the dynamic electricity. prest with the youth's superior and divining measurement of radio-activity. The Ra- (^Continued on page 212) July. 1917 THE ELECTRICAL EXPERIMENTER 173 1917 174 THE ELECTRICAL EXPERIMENTER July, Lightning—How to Protect Yourself From It By W. G. WHITM-'VN, State Normal School, Salem, Mass, electrified and that the found that a difference of potential of 1IGHTNING, that awe-inspiring nat- earth is fositkcly pressure from all about 25,000 volts between battery terminals ural phenomenon which compels the earth differs in electrical possibly 150,000 will give a one-inch spark thru air. attention of child and adult alike, space around it by many— volts. It is not constant, however; con- The duration of a flash of lightning is -i is the cause of about 800 deaths the elec- usually under 1/50,000 second and may be and of 1,500 injuries sustained by ditions are always changing and is variable. a difference only 1/1,000,000 second. Because of per- the people of the United States in a single trical tension Such this is not sufficient to pro- sistence of vision we apparently see the year. It also causes the destruction of of potential as for a longer time. According to cal- many millions of dollars worth of property duce lightning. flash air culations made by Lodge, a discharge from Yearly. When clouds are rapidly formed by rising into the air, enormous quan- a cloud 10 yards square, fuHy charged, at Lightnins is a more vital subject m the currents height of one mile, liberates 2,000 foot- country and small village than in the city. tities of electricity are produced. We do a exactly how it is produced. The tons of energy. This energy is enough to It is rare that lightning strikes in the large not know Sirnpson, explains warm quarts of water to the boiling towns or cities. The isolated building or latest theory, that of Dr. 2^ electrification as resulting from the point and then change it to steam in a object is in greatest danger. The subject the splitting of rain drops into smaller particles trifling part of a second. Such intense heat is of varying economic importance too in rising warms the particles of air to incandescence different states. Records show that light- as they tend to fall thru a rapidly and is the cause of the flash seen. Heated ning does more damage in Iowa than in current of air. In some way clouds do be- conducts electricity better than cold air, any other state. Maryland, Wisconsin, come highly charged with electricity. air New York, Ohio and Illinois follow in the Sometimes they are posithcly charged and so at times other flashes will follow in the first one before air has amount of damage received from this sometimes ncgatwcly charged. When two path of the the clouds or a cloud and the earth are at suf- become cold. These multiple or oscillating source. . . , , , , continue for 1/1.000 to 1/200 That the harmless spark obtamed Ijy rub- ficiently great difference of potential the flashes may second, but altogether bing a cat's fur in they apparently make cold winter and the terrifying lightning but one flash to the eye. of a hot summer day The discharge of are closely related, this cloud, yards belonging as they do 10 square, gives enough in the same family of energ}-, in 1/20,000 of natural phenomena, a second, if properly has never been surmised by the average directed, to hurl 1,000 I)arrels of flour 20 school pupil. In fact many older people feet into the air. When heats the have not thought of this energv' air in the path of the them as related phenomena, even tho lightning discharge it causes sudden expan- Franklin proved their sion with e.xplosive identity in 1752. violence and when the Benjamin Franklin expanded air cools and while e.xpcrimenting contracts vacuum is with electricity a formed, into which air noticed certain resem- rushes again with im- blances between the plosive force. When sparks produced arti- you blow up a rubber ficially and the nat- balloon to an exces- ural lightning. Both sive pressure, explo- flashes were instan- sion results with a taneous gave intense ; loud sound. Wlien an light; followed a incandescent bulb is crooked path ; pro- broken, air rushes induced noise; set com- to the space, and when bustible material on it meets it produces a animals. fire and killed loud sound from the of Frotn observation implosion. These two behavior the similar cases illustrate the he was led of the two, production of thun- belief in to a strong der. One part of a so he their identity, lightning flash may be to per- determined a mile farther away form some experiment from you than the which would prove nearer part. The their likeness or un- thunder from the on July likeness. And more distant part will sent a kite 4, 1752, he reach j-ou about 5 sec- into the clouds during onds later than that thunder storm and a from the nearer part. succeeded in bringing Thus while a flash energy from electrical may be instantaneous, kite the cloud thru the the thunder which string to a key at it- }-ou hear may be of end. This string lower considerable duration. were insu- and key Thunder from several lated from the earth flashes may unite. cord. Frank- by a silk Thunder may be re- lin obtained sparks flected by one or more from the key just like Electrocuted by clouds. In these ways those he had produced Thousands of Cattle on the Great Farms of the West Are Annually Lightning Discharges Which Charge "Ungrounded" IVletal Fences and Dernolish Un- the rumblings, char- in his laboratory, thus rodded" Barns and Outbuildings. The Highest Authorities Recommend That All acteristic of thunder, demcmstrate to Lightning Rods. did he Buildings Be Equlpt With Proper are produced. the world the fact that surface of the is over- Objects standing on the lightning is an electrical discharge. resistance of the intervening air become a part of it and are electri- The boy who shuffles his feet over the come and a discharge takes place producing earth callv charged the same as the earth. Stand- carpet ani draws a spark from the water the common phenomenon of lightning. Sir flash of ing' above the earth's surface they form faucet or gas burner is a dynamo un- Oliver Lodge calculated that a discharge points since the air gap generates electricity and dis- lightning one mile long is probablv due excellent awares ; he from potential of 5.000,000,000 from them to the cloud is less than charges it at a pressure of thousands of to a difference of surrounding earth to the clouds, and volts, but it is generally thought now that the volts. or ten- high. Trowbridge has furthermore, the electrical density It is iisuallv true that the air above the this figure is too — —

175 July. 1917 THE ELECTRICAL EXPERIMENTER

important ning will often jump oflF from a good con- sioii is greater at points, corners and angles ing of liK'itning rods is a very l'ref|ueiitly connected to ductor at a sharp bend, even tho it must than on surfaces. \\ hatever the object may matter. They are lar^e copper plates whicli are buried in a pass thru a poorer conductor. be thru which the discharge starts, it in- mass of coke at a depth which is below There are two ways in which lightning becomes the conductor thru which stantly the permanent water level of the earth.* rods protect a house. First, they serve as from a large electricity passes either to or The metal cage or rods should have a conductors carrying the discharge harm- area surrounding it. If an object only dis- numlier of high points extending above the lessly ; second, they tend to discharge the equal charged an amount of electricity to level of the building; and should have few earth slowly. Often such an amount of that which it held before the discharge, joints and no sharp bends. Our commer- electricity escapes by this slow discharge there would be little danger or violence, but cial currents will follow good conductors that a lightning stroke is prevented, or if not when it becomes the conductor to carry the around any amount of curving, but light- prevented it is less severe. Occasionally a electricity of a consid- rodded house is struck, erable portion of the but the damage is much earth about it, the large less than if the house quantity of electricity had been unrodded. The passing in so brief an idea that lightning rods interval causes violence draw lightning, and are and damage. a source of danger, is A similar discharge unfounded even if the of the earth occurs rods are poorly ground- when an object on the ed. The majority of earth is electril'ied by a fires resulting when near-by cloud by induc- lightning strikes rodded tion and a discharge buildings occur when passes between them. masses of metal, gut- The discharges at the ters, pipes, etc., arc not storm front are usually connected to the light- the most severe. After ning rods or are not the first few discharges grounded. the air seems to become Sir Oliver Lodge a better conductor and classifies lightning as the lightning is less "A" flashes and "B" severe. flashes. The A flashes Any high object are less sudden and vio- reaching above the lent, and are what the earth carries the elec- Germans term cold trostatic field nearer to lightning. Lightning that of the cloud, thus rods are effective pro- increasing the possibil- tection against them. flashes sud- ity of an electrical dis- The B are charge between them. den and violent, and are The tremendous heat what the Teutons term lightning. cneriry which is pro- burning duced from the electri- Lightning rods will not cal discharge of a large always safeguard against these flashes. cloud highlv charged is Actual Photograph Taken After a Severe Electric Storm Showing the Lightning's Toll in Be Surmised, for U Is Very sufficient to heat air Valuable Live-Stock. The Barn Was Unrodded, as May Both the A and B Seldom that Fatalities Occur Where Buildings Are Properly Covered with First-Ciass flashes are fatal to particles to incandes Lightning Rods, Thoroly Grounded in Damp or Wet Earth. lightning cence, to melt minerals man. Ball is strike the and metals, to vaporize solids and liquids produced when the B flashes ground. The .A. flashes are the more com- with e.xplosive violence and to set fire WHAT TO DO IN A THUNDER mon. When a storm is at such a distance to combustible matter. It is little won- STORM. that flashes of light are seen but no thunder that trees are splintered and buildings der is heard, the flashes are termed heat set on fire when they make a path for the If you are out of doors in a very severe storm, it is well to observe the lightning. The thunder may be refracted lightning to the earth—or from the earth electrical following rules for your own protection. above tlie head of the observer or it may for it is believed that fully as many dis- 1. away from wire fences. They Keep be at such a distance that its intensity is charges are from the earth to the clouds may carry a dangerous electrical charge long distances. Cattle in pastures are so decreased as to become inaudible. as from the clouds to the earth. frequently killed from the neglect of If a person forms a part of the conduct- to ground the wire of the fence. Protection against lightning is needed on farmers ing path of the discharge, he is likely to 2. Keep away from hedges, ponds, and buildings, tall chimneys, steeples isolated streams. suffer and yet the stroke may not prove and flag poles. Such protection is secured 3. Keep away from isolated trees. Oak fatal. trees are frequently struck; beech are by use of a metal cage or series of rods The heart is the chief danger spot. It seldom struck. It is safe in a dense with high points and the whole thoroly forest. is not the voltage but the current which grounded. The material must be of suf- 4. Keep away from herds of cattle and passes thru the heart which is the important crowds of people. ficient capacity to carry off large quantities thing. Tho with a given body resistance, 5. Do not hold an umbrella over you. volta.ge causes an increased of electricity and it must not corrode 6. It is safer to sit or lie down in an an increased deter- readily. Copper and galvanized iron are open field than to stand. current to pass. It has never been 7. Drivers should dismount and not mined with accuracy just how much cur- the two metals most commonly used for stay close to their horses. rent can pass thru the human body with lightning rods. The lightning rods or con- 8. Do not work with any large metal implement. It dotibtless varies with individuals. ductors should not be insulated from the tool or safety. If you are indoors: High voltage causes paralysis which may building because the object of the rods is away from the stove and 1. Keep action. gases from the chim- stop breathing, and even the heart's to drain electricity from all objects about chimney. The hot ney may conduct the lightning to and First aid in lightning stroke should be arti- or a part of the building. Conductors down the chimney. ficial respiration, the same as is used to ought not to be placed near or parallel to 2. Do not' take a position between two restore a drowning person. an inside pipe, because the discharge might bodies of metal as the stove and water pipe, for example. An exception to being No danger results when a comparatively jump thru the wall to it, causing fire, or near metals is the case of an iron bed. large current flows thru the lower trunk it might produce a powerful heating effect One of the safest places is on a mattress but as low a pressure as 6.^ volts iron bed. provided you do not touch alone, in it, resulting from induction. A safe- in an the metal. The metal surrounding you has been known to prove fatal, when it guard against such a disaster is to connect makes a safe cage which will prevent the past thru the thorax. the lightning rod system at the highest and lightning from reaching a person inside. The resistance of the skin varies with at the lowest points with inside structural 3. Do not stand on a wet floor nor d.-aw water from the well or faucet. its dryness, moisture, greasiness, and by the beams and water pipes. Sometimes gas 4. Do not stand directly under a chan- area which is in cont.ict with an electric pipes are connected but because of the in- radiator, nor on a register. delier, near a conductor. A bare wire carrying our ordi- flammability of gas, many prefer not to 5. Do not use the telephone. nary lighting current at 110 volts or 220 connect them. All exterior metal work of volts pressure may be handled safely if the the building, as gutters, railings, etc., cither •Specifications for installing liehtning rods are skin which the wire touches is dry or if the should be connected to the lightning rod at given in Technologic Paper No. .>'>. Bureau Stand- person's boots by which the current leaves a level below their own or they should be procurable from Government Printing ards, at 2

dif- is that mysterious phenomenon are enabled to present thru the courtesy of The tuning fork may be adjusted for SOUNDof nature by which ^ve are able to Prof. Miller, who is considered a verj' ferent frequencies when desired and in gen- communicate intelligence to one an- high authority on the science and physics eral corresponds to the usual musical tuning electro-magnet other, and by wb.ich it becomes pos- of sound, illustrate but a few of the hun- fork, except that a small sible to accomplish many industrial dreds of extremely interesting demonstra- is placed between the two prongs. When a current is thru this electro- and scientific wonders, and according to tions and peculiar devices which have been battery past Professor Dayton C. Miller, of the Case worked out in the physical study of sound. magnet, it attracts the opposite leg and sets School of Applied Science, Cleveland, O., One. of the accompanying illustrations the fork vibrating, the battery current be- we may define sound as the sensation re- shows how laboratory apparatus may be ing interrupted at every swing of the tun-

Wave Prof W C Sabine of Harvard University Has Made the Accompanying Remarkable Photographs Showing First—the Start of a Sound Into an Auditorium, (Left). At Center, the Sound Wave Photographed 3-100ths Second After Its Production on Stage. Right— Echoes in 'Reverberation." in a Theater Developed from a Single Sound Impulse in 14-100ths Second, Resulting What We Call

platinum con- suiting from the action of an external set up so as to cause a single taut string ing fork limbs by virtue of a stimulus on the sensitive nerxt apparatus of to vibrate in a single loop. In taking the tact mounted on the vibrating fork. The black string consist of a silk cord. the ear. In other words, it is a species of photograph of the vibrating string, a may tension of the reaction to this external stimulus, excitable background was provided, so as to show By simply changing the string arranged, it can only thru the ear, and dis- so be made to vibrate in va- tinct from any other sensa- rious sub-divisions corre- tion. Atmospheric vibration sponding to its harmonic normal and usual is the over-tones. For instance, means of excitement for the it may be caused to show ear. This vibration originat- two-loop, three-loop and ing in a source known as the five-loop formations, repre- soiiiidinff body, which is it- senting respectively the first, self always in vibration. For second and fourth over- instance, the source of the tones. sound may be constructed es- One of the most remark- pecially to produce a certain able sound analyzing instru- quality as in a stringed in- ments is Professor Miller's strument, whether the string Pluinodi'ik. This instru- in sev- is plucked or Ijowed, and its ment has been made consequent vibration trans- 1^ ^ eral different forms for es- ^ and ferred to the wooden or Jr] ^^^ pecially analyzing other sound-board and which K^^Jj^l studying the various funda- harmonics in turn impresses the motion ^^^^iB mental tones and upon a larger mass of air. of musical and other sounds but the one The word sound is tised in the laboratory, designate Interesting View of a String Vibrating in a Single Loop, Co rresponding to here shown is probably of by the scientist to Only. An Electrically Vi brated Tuning a Simple Tone of a Fundamental the greatest interest to the the vibrations of the sound- Fork Is Used in This Experiment. of the ing body itself or those layman. By rneans (here il-- which are set up by the soimding body the loop of vibration more clearly. This projection type of phonodeik enabled in the air or other medium, and which single loop corresponds to a simple tone lustrated). Prof. Miller was are capable of directly affecting the £ar, consisting of a fundamental only. The to present some very startling effects lectures in York even tho there is no ear to hear; the sound string is secured at one end to a stationary in his recent New for going forth just the same. support, and at the other to one prong of a City before the American Association The accompanying illustrations which we special electrically-operated tuning fork. the" Advancement of Science. When the

Many Valuable Studies of Sound Waves Can Be Made by Means of "Sand Figures." The Sand Is Placed on a Diafram Which Can Be Vibrated at Any Desired Frequency or Note. July. 1917 THE ELECTRICAL EXPERIMENTER 177 word "War" for instance was pronounced rarefactions which are projected thru that the music rever- into the horn of the phonodcik, its tiny re- space with a velocity of 1,132 feet per sec- berates thruout the volvinK mirror caused a narrow heam of ond fat 70° Fahrenheit), and for the tone auditorium. hffht to dance wildly on the sta^c screen, "middle C," the distance from one com- A great deal of study but when the word "I'cace" was spoken into pression to the next is about four feet. can be and has been the instrument, the lisht beam smoothed It woulfl prove very desirable indeed to carried out in the realm out remarkably, exercising a wonder I id and be able to actually photograph sound waves of sound studies by truly remarkable psychological effect on the in air, but no practical means have as yet means of sand figures. audience. been perfected for photographing waves These are known as The operation of the phonodeik, which of this size. The accompanying photo- Chladnis' figures, and is the result of many years' study, is based graphs of a cross-sectional model of a one of the accompany- upon the use of a vibrating diafram. which theater showing the progress of a sound ing illustrations shows is placed at the base of the horn shown. wave from the stage is due to the re- three interesting forms The movements of the diafram due to searches of Prof. W. C. Sabine, of Har- produced by certain vocal or musical sounds projected into the vard University. Photographs such as these, sounds. A large num- horn cause it, with its vibrating mirror, showing the sound wave at any instant, ber of patterns can be to project a tiny beam of light, which fall- are taken by instantaneous exposures and formed by the various ing upon a motor-driven revolving mirror, are obtained by the snapping sound pro- sounds, and which pat- is thrown on to the white screen on duced by the electric spark discharge terns or figures are al- the stage in the form of a long wave. The from a Leyden jar. The sound thus given ways the same for the movements of the diafram are magnified off by a Leyden jar discharge consists of same note. forty thousand times or even more, pro- a single wave containing one condensation As an example of ducing a "light" sound wave on the screen and one rarefaction, the wave length of what has been accom- which may measure ten feet in width and which may be 1/16 inch or less, and the plished in this direc- even forty feet in length, suitable for a sound is relatively a loud one. Now if, tion, it may be of in- practical demonstration of the physics of while such a sound wave is past over a terest to state that, with sound to an audience of any magnitude. photograph plate in the dark, the wave is a diafram of glass held The projection phonodeik possesses many instantaneously illuminated by a single dis- in circular rings and placed horizontally, the vibrator being attached

to the under side ; when sand w a s sprinkled o\ er the diafram. figures were obtained as the diafram was made to respond in suc- cession to each one of eighty pipes corresponding to frequencies from 129 to 12.400. The characteristic no- dal lines produced for each frequency were then photographed. Our long, narrow illustration carrying the continuous undulating sound wa\e as shown at right is one of the most remarkable records of vocal music ever obtained. It was made in Professor Miller's laboratory, and The Marvelous "Phonodeik" Devised by Prof. Dayton C. Miller. Which, by Extremely Delicate Electro-Mechanical Attachments. Permits a Lecturer to Project on a Screen the Undulations is part of a record of of the Speaking Voice. Magnified 40.000 Times! Truly a Scientific Masterpiece and An world-famous opera Invention of Far-Reaching Importance and Application. singers singing the sex- tette from "Lucia di remarkable «]ualities. among which we find taut electric spark, then the light from the Lammermoor." The along the that, if the revo'.ving mirror is kept sta- spark will be reacted by the sound wave white dots tionary the spot of light on the screen which will then act as a lens and register edge of the record moves in a vertical line as the diafram itself on the plate. The accompanying represent the time

periods 1/100 of _ a vibrates ; tho these movements are super- photographs, due to Professor Sabine, show second a/'art. The orig- p'osed, their extreme complexity is shown some of the work carried out by him in since the turning points are made evident studying the problem of auditorium acous- inal photographic rec- of this bit of opera by bright spots of light. If we turn the tics. ord mirror slowly by hand, then the production is nearly four times as make such sound wave photographs, of the harmonic curve by the combination To long as the one here re- a small cross-sectional model of the audi- produced. particu- of vibratory and translatory motions is The torium is first made. The photograph plate demonstrated. By the aid of a simple lar section of the rec- is placed behind the model ; the sound is tuning fork, the simplicity and wonders ord illustrated shows produced on the stage at the right, and of the sine curve are exhibited grafically. the voice undulations the resulting wax e is propagated out into the and variations of Mme. By using two tuning forks, it becomes pos- auditorium with a velocity of 1,132 feet Tetrazzini Signor sible to demonstrate before a large audi- and per second. The second view shows the ence, the combination of sine curve waves. Amato, I. r., soprano period just before the main sound wave and baritone Also the relations of loudness to ampli- voices reaches the balcony, and the final photo siiii/iny softly. This tude, and of pitch to wave length may shows the wave 14/lOOths second after the particular section of the be fully demonstrated. As the sound production of the original sound on the voice record has a dur- changes at the phonodcik apparatus, the stage, when the main wave has reached the ation of .80 second, and light wave follows in consequence, and the back of the gallery. It will be noted that is for a single note. projected image on the screen undulates a large number of echo waves appear, and rythmically. and in a most remarkable man- which seem to come from many different The Voice Record at the ner. directions, but which are actually generated Right Shows the Undu- lations Occurring When Three interesting illustrations are pre- by the one original impulse. The multiple Tetrazzini and Amato sented herewith which show the progress echoes continue to develop with ever in- (Soprano, and Baritone) of a sound wave in a theater; the wave creasing confusion until finally the sound Warble a Note from "Lucia di Lammer- gradually is thruout the auditorium, when swelling out into the auditorium diffused moor.'" Each Dot Is until the main wave has reached the back we have the condition known as ri-,'i-rhrr- 1-100th Second Apart: of the gallery and been reflected. alion. This explains the effect occurring the Time Period of the Record Shown Is .80 Sound Miller, in a theater, hear anyone say waves, according to Prof. when we Second and Is for a consist of alternate condensations and that the singer has such a powerful voice "Single Note." —

178 THE ELECTRICAL EXPERIMENTER July, 1917

TELEPHONE AND RADIO IN WAR- many thousands can be found just back dreds, even thousands of men. He TIME FRANCE. of the battle lines. The telephone, tele- must not make a mistake and his The .French army has perhaps made graph and radio stations are often located instruments must always work—so long greater use of all electrical means of com- in the basement of a once beautiful cha- as his antenna stays up. municating intelligence than any other teau or church. NEW INVENTION 'PHONES POLICE—"THIEF'S HERE." Burplar detection is made a matter of certainty and simplicity by means of a device invented bj- Lee A. Collins, of Louis- ville, Iventuck\', Patents are pending on the invention. With the installation of the alarm, a burglar in forcing or gaining an entrance sets in motion the mechanical device, which then summons the police, giving them the name and address of the person whose home or office is being entered. Another type of the device does not operate with a phonograph attachment, but instead has a buzzer which warns central, who in turn reports the matter to the police. Another t\-pe of the invention has a bell which is controlled by thermostats, and gives fire alarms as well as burglar alarms. The alarm does not cease if a window Here We See Two Interesting French War or door is closed immediately after be- Pictures. At Left Telephone Switchboard — in.g opened, but continues at work until at Headquarters. Right— Radio Station off. I Near the Battle Front "Somewhere in the connection is cut The device is i France." simple in construction, and can be attached to any telephone. A special attachment makes it possible for bank or express company cashiers to start the mechanism by militar\- organization of the present time. The central telephone switcliboard shows pressure of the foot or knee in the event The illustrations herewith show a central how cable lines are brought in from every an attempt is made at a hold-up. Two telephone switchboard at army headquar- important army division. By means of dry cell batteries operate the entire sys- ters and a typical radio station, of which the flexible cord and attachment plug con- tem. If the bank cashier is held up, for nected to the wall telephone instrument seen instance, he simply obeys orders and throws TORPEDO NOW USED AS LAMP- in the picture, an officer of the command- up both hands if he deems it best, but POST. ing staff may instantly ring up any divi- his foot is busy meanwhile, and when the The accompanyiui: illustration sliows an sion commander and transmit orders or foot operated trip-switch closes, the Col- odd electric lamp-post in use at Xewport, receive a special report as to the progress lins automatic telephone alarm immedi- part .sets It raises the telephone R. I. It is formed of a one-time danger- of a battle at any certain of the front. ately busy. ous torpedo, whicli was captured in the The head telephone set lying on the hook (in another room, so the thief will Spanish-American War. The torpedo has table is used to listen in secretly into any line running from the trenches to headquarters. Thus the officer in charge may know at once if unau- thorized talk i~ going on. But to the radio operator comes a full share of mys- tery, romance and action. He sit3 with his head receivers clamped tight against his ears while from out of the bound- less ether there When the Bank Robber Appears Now, the Cashier Simply Presses a comes the news Button with His Foot. This Causes a Special Device in Another Room to Lift the Telephone Hool< and Start a Phonograph Which Gives of victory or de- Central the Call for Police. feat—the call for reinforcements—messages of every descrip- not become desperate) and simultaneously tion and from many points along the battle starts a small phonograph located near the front. Needless to say the military radio telephone. It carries a special record, an- operator holds a most important position nouncing the bank's name, the location an importance \yhich the peace-time and the news that the "thief's here!" It operator never even dreams about. In repeats the message over and over again, his hands there may lie the differ- notifying Central, who at once informs ence between life and death for hun- police headquarters.

been securely anchored in the ground and the electric feed wires, supplying the lamps A trap drummer has discovereo that elec- at the top with current pass thru the hol- tric lights installed inside his drums keen low shell. The relative size of the torpedo the moisture out and makes the drumheads tight. may be judged by comparing it with the marine standing beside it. Rather an ex-

Photo Coi-yright by Press Illustrating Servict-. pensive lamp-post, as lamp-posts go. this The new battleship Tennessee will use particular one having cost about 27,500 electrical horsepower, enough power A One-Time Formidable Torpedo. Captured $7,000 in the Spanish-American War, Now Serves originally when the Spanish torpedo factory to furnish heat, light and power for a city as a Lamp-Post at Newport, R. I. turned it out. of 100,000 inhabitants. !

179 July, 1917 THE ELECTRICAL EXPERIMENTER Speeding Up Vote of Congress by Electricity

Instead of Wasting an Hour and a Half in Which to "Call the Roll" Alone in the House of Representatives at Washington, a Newly Pro- posed Electric Voting System Will Cut the Time Down to a Few Minutes, Resulting in a Savmg of Thousands of Dollars Annually. photographed. HAVE you ever been present at the roll there is some rcas

The U. S. Signal Corps Wants You be ob- the information of all applicants in "Equipment for all men enlisted, such as In addition to operators, men must FORSignal Enlisted Reserve Corps, we uniforms, bedding, messing utensils, etc., tained who have had technical training, or will give below the general plan of the will be available for issue at the camps of who have had an education which training and preparation the new units of instruction. Each man enlisted will from enable them to quickly grasp the mechanical Signal Reserve Corps are to receive before the time he reports receive the same pay and electrical work incident to the opera- in they are fitted for work in connection with and allowances as the corresponding grade tions of a Field Battalion Signal Corps addition other arms of the service. in the regular army. They are also entitled active service. The men must, in and ath- "In the first place," says Major Carl F. to transportation in kind and commutation to above qualifications, be strong Hartmann, of the N'ew York Headquarters, of rations at .'>0 cents per meal for the time letic, and preferably horsemen. is an "we have attempted to enlist only such men of actual travel from their homes to places ".•V Field Battalion of Signal Corps as are technically qualified to carry on the to which ordered for active service. If organization for which college and techni- usual functions of the Si.cnal Corps without transportation in kind is not furnished from cal men are especially adapted. The work is additional technical training. We expect to their homes to place ordered for active active and interesting. It is necessary give them additional training concerning the service, they are entitled to reimbursement everywhere, on the battlefield as well as on use and operation of equijiment directly for the actual necessary cost of such trans- the lines of communication to the bases. prin- pertaining to Signal Corps Battalions, also portation. The Signal Corps' drills involve the an intensive course of military training "The term of enlistment is for four years. ciples of nearly all the other branches of the the interesting which will make our organizatitm an elh- However, the President of the United States Army, in addition to ap- cicnt military unit for active service. has stated that the Reserve Corps will be paratus necessary for the transmission of are prepared to follow "Our advice to men wlio enlist is to con- held in active service only during the period information. We tinue their ordinary pursuits until they re- of the emergency. the cavalry at whatever gait they desire to with the ceive the call from the President, then report "It is proposed, in the Eastern Depart- take. We work in conjunction rely for imnie

180 THE ELECTRICAL EXPERIMENTER July, 1917 "Ham" Jones—Scientist By H.\RL.\N A. EVELETH

ALFONSO MARMA- Come ripht in and make j'ourself at home." "Ham" turned on a light, and there- HENRYDUKE JOxXES, alias "Ham" And with that he gave me the "glad hand" upon my eyes opened wider and wider Jones, was a \outh of seventeen and a pat on the shoulder. as I gazed in mingled awe and ecstasy summers, awkward and lanky, "The pleasure's all mine!" I replied; I, upon the vast accumulation of multifarious with auburn hair and freckles, alias "Spin" (short for "Spindle") being electrical equipment which adorned the and blue eyes which imbibed the beauties modeled somewhat along the graceful lines four walls and portions of the ceiling and of nature—several sat near him in "Latin of a Geissler tube. floor of the laboratory; a bewilderment of 1"—thru the lenses of omnipresent, iron- "Come right up stairs," chirped "Ham," coils of wire, switches, bells, insulators and rimmed spectacles. "Ham" was some boy. so I trailed along behind him, up two flights instruments of every type and form imagin- He had attained a wide reputation among of stairs to a hall leading to the laboratory able—and surmounting the whole, a crudely his fellow students as a wizard of wire- in the attic. lettered sign bearing the ominous warning:

y/AV>iil

" .... He Picked Up a Fine Wire from the Floor, Fastened It to tiie Coll and Prest the Key. Suffering Cats! ! ! My Shoes Became

Full of Carpet Tacks and I Leapt so High that My Head Nearly Hit the Ceiling. . . . 'Hen' Got to Laughing so Hard He Could Not Keep His Stick on the Key." less telegraphy and as an authority on all "There's mj' room, you can open the the intricacies of "hook-ups" and electrical door and step right in," gurgled "Ham." phenoinena pertaining thereto; in fact, the "I left something down stairs, I'll be back DANGER pages of his "Caesar" housed innumer- in a moment." able and priceless diagrams of diagrammatic "All right," I said, innocently, and then 150,000 VOLTS data, this grasped the knob of the door. I had while a rear view of assemblage This of students disclosed the existence of a pushed it about half open when the knob All Persons Entering secret service system of communication suddenly turned red-hot, or something, and Laboratory Do So At whereby others who desired information of it would not let go of my hand for all a teclinical brand could obtain the same I could do to persuade it to. "Ham" Their Own Risk direct from the hand of the renowned stood on the stairs, with his hand beneath scientist, "Ham" Jones. Thus it was with the railing, and laughed so hard that he a great feeling of joy and expectation that finally sat down on the steps to keep from "Hen," I said, in a plaintive tone, as 1, a humble member of the secret service tumbling the whole length ; thereupon the if to ask him for a job. "I guess organization, accepted the magnanimous in- knob turned "cool" and I yanked my hand about I'll stand over near the doorway." I was vitation of "Ham" to devote an evening away. careful to call him "Hen", for I feared of my leisure time among the electrical "You big boob !" I yelled, for I was dire consequences if I should offend his paraphernalia of bis far-famed laboratory. scared and about ready to choke. "Do dignity. I ascended the steps of the front porch you want to kill a feller?" of "Ham's" abode with faltering steps that "Aw forget it. You have to get used "No, )'0U stay right where you are," memorable night, and I pushed the push to shocks if you're going into the wire- he retorted. "Tliere will be no danger as of the push-button with the end of an ink less business." long as vou keep your hands off the wires." eraser; for I had heard rumors of "big "Yes —well, will vou let me trv it on "But iiow about those 150.000 volts?" sparks" and unexpected— shocks, and rub- you?" "Don't you w'orry about them. They are ber is an insulator "Ham" had told me "Perhaps, later on, but I've got lots to Tesla coil volts, and they won't do more so. show }'ou —and besides, it's a waste of than knock you down. I'll save the fire- "Hello! 'Spin'," quoth "Ham," as he 'juice.' Come in and I'll show you my works for the' last, so that if you get swung the door open. "Glad to see you junk." So in I went. killed you won't miss any of the show." ;

July. 1917 THE ELECTRICAL EXPERIMENTER 181

"Uh huh!" I gasped; then wondered it her 'O. S.' to 'B. H.'—Hear that low spark? "Yes," I said, "1 can hear people walk- I liad not better make a break lor the That's 'H. A.' shooting the baseball scores. ing around. Keep quiet a moment." The door wliile 1 had the chance. Gee ! 1 wish I could copy him, but I can't, hissing and scraping noise gradually died "Take a scat," said "Hani," "and I'll he's using Morse. I guess you have heard down, and then there came to my ear a show you the wireless." So I gingerly enough. Take the receivers off and I'll series of distorted words to the effect that seat, after first turning it upside- on with the ,". took a go show." . . I am sick and tired of the com- down to discover the jiresence of any So I did as commanded, thanked him pany which Henry continually brings to diabolical mechanism which might be con- for the told demonstration, and him, in this house . . . they are a nuisance cealed in the cushion. earnestness, what remarkable person he . . . . a he is failing in his Latin . . . 'Spin'," he said, a of must be to comprehend the technique "\ow, with wave of some night . . . throw his old wireless his as he assumed a professional atti- such complex mechanism. ." hand, out of the window . . Whereupon I " tude, "that apparatus over there on your "Say, 'Hen' I inquired, noticing the dropt the receiver and said to the un- right is called the transmitting set. It is contents of a box reposing in the corner, suspecting "Hen," "It's getting pretty late. hard for me to explain the function of "where did you get all of those fuses?" I think I had better go home." the various instruments in terms whicli "Fuses? Those are all burnt out. I "Hen" urged me to stay. "I will now will be understood by the layman, so I'll bought them at a nickel apiece, and there's show you the Tcsla coil. I can't operate try to use simple language. This instru- about two dollars' worth there in the box. it very much in the evening, for it blinks ment here is called a transformer, and it I threw another dollar's worth away last the lights and is apt to cause trouble in takes the 110 volts and cuts them up into night at a couple of cats. About a week the family." He tinkered with the switch- pieces until there are fifteen thousand volts. ago 'pa' served me with an ultimatum to board, made new connections, then prest That is thirty times as many volts as run the effect that I was to buy no more fuses, the key with a yard-stick and blandly con- the electric cars, so it is a very danger- so I have hit upon a scheme whereby they tinued, "The sparks I am about to show ous current to fool with. From the trans- won't burn out so easily. I take the top you consist of over one hundred and fifty former the volts flow into this condenser, off a burnt fuse and fill it with tin-foil, thousand volts. They electrocute men over which piles 'em up like sardines, until then force it back onto the fuse, and be- in Sing Sing with two or three thousand there are so many that they jump across hold, I have a new fuse which lets more volts, so you can imagine what a danger- this spark gap. That coil of wire is called current thru than it did when new ! You ous current this is. That's it," as I backed a heli.x. The volts get going around it so need not tell anybody about it, for I am away, "stand on the rug there and you will fast that some of them shoot off into the thinking of getting the idea patented." be safe." "Ham" Jones punched the key aerial, and from there into the ether. That's with his stick and long, purple sparks shot about all there is to it. The code is made off from the knobs of the "Tesla coil, by punching this key." flicked ARTICLES IN THE AUGUST about like the fangs of a boa con- "That's a pretty complicated affair, all strictor and snarled and crackled like a "E. E." right," I ventured to say, "but there's one wounded "rattler." I stood on the rug in thing I don't understand. What do you ll'c have a luimhcr of fine things in mute admiration of this exhibition of arti- mean by saying the volts go into the ether? store for the Atiyust issue of The ficial lightning, ever fearful of an impend- I took ether when I had my arm broken, Electrical Experimenter. Among ing death. "Hen" let the sparks play over but I don't see what it has to do with the 125 articles already scheduled for his hands and even pulled sparks from M-ireless." the August number the Editors take conspicuous portions of my anatomy. pleasure in announcing the "Haw ! Haw ! The wireless ether is not follow- Surely, he was a genius, a second Edi- ing:— a liquid, it's a substance, er 'incon- son, a great engineer to be ; I told him so, ceivably attenuated which is supposed to be "The Unsinkable Ship"—A solu- but he only laughed and told me to wait coextensive with infinite space.' That is tion to the submarine problem by a moment and he would show me some- the only way I can describe it. I don't. Hiram Maxim himself. A feature thing better. He picked a fine wire up article class. know much about it myself. However, of the highest from the floor, fastened it to the coil and these instruments over here are for re- "The Radio Bomb"—A thrilling prest the key. Suffering cats ! ! My shoes ceiving. The messages come down the wireless story that will keep you became full of carpet tacks and I leaped aerial, and then pass thru those tuning guessing every minute by C. M. so high that my head nearly hit the ceil- coils, the receivers and the detector. The Adams. — ing; then down I came again on that red- detector lowers the rate of vibration of "Standard Time" In which our hot carpet, and thus I danced in agony un- the incoming current so that you can hear friend, Thomas Reed, discourses in his til "Hen" got to laughing so hard that the signals, while the tuner regulates the inimitable style on the use of spider he could not keep his stick on the key. wave-length." webs and electricity in checking stand- I was mad clean thru, but what could "I think I understand, but can I hear ard time. Don't miss it —Readers. I do with "Ham'' leaning against the wall, a message?" Selenium, some ne'n> electrical and so merry that the tears fairly rolled out of "Sure thing! I've got two, good (get scientific aspects of this little known his eyes? that), one-hundred-ohm receivers and substance by Albert W. ll'ilsdon. In about ten minutes the "Wizard" re- we'll have one apiece." The Marvels of Radio-Activity. gained his former dignity and proffered an We clamped the receivers on our head, Part // by Jerome S. Marcus, B. Sc, explanation of his ingenious trick. "L'n- £.)" and "Hen" monkeyed with the switches and (Ch. derneath that rug on which you so kindly the detector and slid the contacts up and A Homc-Made Arc Searchlight for stood." said he. "are a couple of square- down the tuning coil as if he was sawing the Amateur by Frank M. Jackson. yards of chicken-wire. I connect it with wood, but the only thing we heard was An Electrolytic Interrupter for Low the coil by means of this fine wire, when- the test buzzer. J'oltages by C. A. Oldroyd. ever I desire to pass the spark into the "There must be a loose connection some- Making An Electric Clock by feet of whoever is standing on the rug. where," explained "Hen", as he made a Thomas Reed. It works better on the ladies, for the soles minute examination of the wiring. Finally The Present Status of the Audion of their shoes are not as thick as men's. we heard a series of loud buzzes which by Dr. Lee de Forest. I W'Orked it on our Parson the other day, suddenly broke into a long dash. "Hen" Complete Details for Building a and the sermon I got from 'pa' a few worked the tuner for all he w'as worth, 20,000 Meter Undamped Radio Re- hours later was sure brief and right to the but could not tune the station out. ceiver by ll'm. Burnett, Jr. point." and E.rperimental Radio " "There's no use tr>ing, it's another one Amateur 'Ham'—er, 'Hen,' that's a pretty clever of those Hams who sits on his key for the Research. Part II by Raymond Fran- stunt, even if I was the goat." I ventured pleasure of hearing his spark. Those fel- cis Yates. to say. "Those big sparks of yours are lows make me sick ; they have a habit of more interesting than the wireless.- but I " doing it just as I start to listen to don't understand the peculiar way in which Just then "Hen" lifted his elbow and the "That is a good scheme, all right," I re- the)' seem to work. I don't see why they noise stopt. He didn't say a word; just marked. "I will say nothing about it; but should jump into my feet when I do not " looked a bit foolish and sawed his tuner what is that arrangement over there on have a second connection harder than ever. Finally he jumped up, the wall?" "Of course you don't," interrupted "Hen." stuck his head and arms out of the win- "That is a little contrivance of mine "I can't explain the reason in simple lan- dow and did something which suddenly whereby I am enabled to listen to con- guage. Now if you will step over here made the buzzes come in at a great rate. versation which takes place on the first near the bed I'll show you some more in- "I guess that's one on me," said "Hen." floor. It consists of two microphones, a teresting ideas. Before retiring I pull the "I forgot to open the ground switch. Now battery and a telephone receiver. I in- shade, shut the door and turn on the elec- listen. Ah ! There's Colon—keep quiet stalled the microphones last Sunday when tric light. -Ml three of these are arranged now, don't talk—hang it all. there's that the rest of the family were at church to be worked electrically from a series of fellow who sits across the aisle from me one is located behind the boiler in the push-buttons located near the head of my in Latin one; he's always hutting in on kitchen and the other beneath the radiator bed. Step over here and I'll show you me when I am trying to do long-distance in the parlor. Hold the receiver up to how the curtain works." work— listen I There's the 'R. B.' giving your ear and see if you hear anything." (Continued on page 217) 182 THE ELECTRICAL EXPERIMENTER July, iqi7 SEVENTEEN PICK UP FALLEN 20,000 Volts Direct Current WIRE. When, a sufficiently high potential dif- These machines are divided into two sets The curiosity of the human race knows ference is imprest between two parallel of ten machines each and one set of twen- no limit. In one of our large Eastern wires, or a wire and concentric cylinder, ty machines, each set being driven by a cities, says the Au Sable Nezcs, some men separated by air or some other gas, this belt-connected continuous-current shunt were at work installing a new wire on a gas which for low potential gradients is a motor. The generators are mounted on in- busy street. For some reason the part of the wire that was already in place broke near one of the poles and fell to the ground. As the work of erection was not yet completed, the circuit was not in service and the wire was deaQ-=-but this fact was known only to the employees of the electrical company. One of the men, knowing the danger to the public from fallen wires, but also knowing that this particular wire was harmless, stood near by to note what action the passing throng would take. In fifteen minutes approximately 200 persons past this point, and of this number twenty-two showed some curiosity regarding the wire. Of the twenty-two who stopt seventeen, all adults who might reasonably be supposed to know •better, stooped down and took hold of the wire, or at least touched it, and then, finding it harmless, past on. If the wire had been charged to a high potential, the first of the seventeen "doubting Thomases" would have been killed. HOW BEES BECAME INTERESTED IN TELEPHONY. If C. W. Weston, manager of the Port Byron (Xew York) telephone company, had been in the honey business he might have welcomed the visit of a full sized swarm of bees which took refuge in the company's terminal box located on the main street of the village. After faking council with the local physician and druggist, and receiving no satisfactory advice, Mr. Weston's Electric Generating Plants Ever Built. It Is Used for Special One of the Most Remarkable mind wandered back to the old days on the Test Work and Comprises Forty 500 Volt D.C. Dynamos, Which. All Driven and Connected Together, Develop 20,000 Volts Direct Current! farm where on one occasion he had been compelled to test conclusions with several verv good insulator breaks down and be- sulating bases and the shafts of the sepa- skunks. He procured some bi-sulfate conies a partial conductor. The phenoinena rate machines are connected by insulating of carbon and with it saturated a handful connected with this character of conduc- couplings. In the newer part of tlie instal- of cotton waste and packed it in every tion thru gases are known collectively by lation one terminal of each machine is per- aperture of the terminal box. A careful the name corona. The failure of the gase- tiianently connected to the frame of that and cautious examination was made the ous dielectric separating the metallic con- generator, in order definitely to limit the ductors is made evident by a flow of cur- strain on the machine insulation to the rent from one conductor to the other, by a voltage generated in one armature. cases, power loss and, in practically all by The field of each machine is connected the appearance of light at either one or directly across the artnature terminals, a both conductor surfaces. In some cases single-pole knife switch being included in light appears in the intervening space. the circuit in order that the machine may Since the present theories as to the mech- either be made to generate or to run idle anism of corona formation do not satis- at will. These switches were operated by factorily account for all of the observed means of a hard rubber rod appro.ximately fur- phenomena it was decided to carry out eighteen inches in length, since they may ther investigations, says G. \V. Davis and be 20,000 volts above earth potential. The C. S. Breese in the Proceedings of the generators were run somewdiat below rated .A.T.E.E., in the hope that when enough speed in order to limit, to a safe value, the data wtre accumulated some theory based voltage generated with no external resist- on fundamental principles and explaining ance in the field circuit. the ol)scrved phenomena might be evolved. With this purpose in mind it was attempted to simplify the conditions of corona READING BY WALL PAPER IS formation. THE LATEST INVENTION. A wire and concentric cylinder were used automobiles and torpedoes in order to make the field radial and to Two-wheeled ears chase ships by get away from the secondary effects due to with mcclianical to are brain of Pro- the high intensity electric field surrounding sound waves products w'ho gave a a second wire. Hydrogen w-as used as the fessor ^lontraville M. Wood, inventions at the dielectric in order to minimize the effects demonstration of his recently. due to changes in the chemical constitution Union League Club he asserts an ex- of the gas. When air is used as the dielec- By radioactive paints manu- tric the formation of ozone may produce pensive mural decoration may be light marked changes in the voltage necessary factured which will furnish so much for corona formation. Continuous poten- a perron may read by it. Bee-lines and Telephone Lines May Not Have "Within ten years." he said, "there will Any Comn-.on Bond Existing Between Them, tial was used in ordei* to separate the ef- Thought So As automobiles run- But These Bees Evidently fects accompanying a discharge from a be plenty of nonskidding They Calmly Proceeded to Build a Home In positive wire to a negative tube from those ning on two w'heels. built on the principle a Telephone Cable Terminal Box at Port Byron, N.Y. which are characteristic of the discharge of the monorail and retaining their e(|ui- from a negative wire to a positive tube. librium liv means of the gyroscone." of which Pro- next evening, when it was found the deadly The continuous f direct current") voltage The "listening torpedo." fumes had done their work. The accom- used in these investigations was obtained fessor Wood is the inventor, is fitted with panving cut shows the dead bees. Xote by means of a battery of forty 500- volt. delicate mechanical devices which record the started in the top right hand cor- 2!i0-watt. continuous-current, shunt-wound the sound waves made by a .shiii's screw comb generators connected in series. and draw\s the torpedo in that direction. ;

183 July. iqi7 THE ELECTRICAL EXPERIMENTER

A COMPACT ELECTRICAL ball posts at the c.xtreme right hand arc A NEW TELEGRAPH TEACHING HOSPITAL. used- for connecting the apparatus used in MACHINE. of the X-ray. Each pair of The instrument here illustrated is intend- Elcctro-thcraijcutics is steadily claiminp; the production are controlled by an individual ed to simplify the details of telegraphy. It the attention of the present-day electrical terminals applying the gen- is operated without the aid of an instructor. engineer, owins to the rapid strides lieinj,' switch. .Apparatus for erated ozone may be seen in the u|)per All that the beginner nas to do is to follow left corner, and this consists of a the chart and execute the dots and dashes special glass tube fitted with a fine as they are printed thereon. It was in- nozzle. vented by Mr. George J. Little and is called The generating and main instru- the Simplotjraph. ments are contained in the lower por- The object of having a key for each let- tion of the cabinet. A motor-driven ter is to allow for the use of both hands si- suction pump is utilized for the pro- multaneously if desired. This gives the duction of mechanical vibration and beginner plenty of finger exercise. This the device which is applied to the pa- instrument is claimed to represent distinct tient is noted on the left side of the cabinet. It consists of nothing more than a rubber tuljc placed in a special receptacle and connected to the pump by tneans of another rubber tube. A second pump is used to force out the generated ozone. This is made in a glass tube hung on the door of the cabinet seen at the right. The terminals are connected to the high frequency circuit by means of brass clips when the door is closed, while the ozone is past thru a rubber tube to the pump, and finally to the glass bottles as above mentioned. Four The "Simplograph"—An Attempt to Make the Learning of the Telegraph Code as Simple as Possible. A Buzzer high tension condensers are Sounds the Signals for Radio Students. employed and these are placed in each corner of the lower advantage over the single key or other me- compartment. The Leyden jars con- chanical devices that are now on the mar- tain salt water as the interior coat- ket. A dry cell or two, connected up to A Remarkable Electrical Outfit of Extreme Com- ing, and connection is made thru a the keyboard here show^n, causes the buz- pactness WInich Yields Practically Every Form carbon rod. The Tesla transformer zer to time of Current the "Doc." May Require. It Is Rated mounted thereon respond every at 5 Kilowatts. is placed on the door of the cabinet the keys are deprest. Incoming signals are and its connections are terminated received on the buzzer also. The key be- acting as made in this field, competition at copper jaws which interlock on metal fore each letter on llie chart must be de- the all-important stimulant. lugs when the door is closed. The prest the proper number of times for the the electrical laboratory of the Formerly, high tension current is supplied by a S- corresponding dots and dashes. The device physician was littered with various appara- kilowatt closed-core transformer and this should prove of value lo students. save to tus, of no real consequence occupy is placed in the base of the cabinet. Its against the front contact, permitting cur- space. But these conditions have been rap- secondary terminals are led to a special find that the rent froin a small alternating current trans- idly overcome, and to-day we rotary spark gap which is placed in the former to energize a winding on a lamina- modern physician insists on his apparatus, rear. where electricity is employed, shall lie as ted iron core. On opening the main line compact and yet as complete as possible. A TELEGRAPH SOUNDER THAT and consequent demagnetization of the re- Various equipments have been devised and WORKS ON A.C. lay the armature makes contact with the introduced but none of these compare with Telegraph sounders all operate on direct back stop, thus energizing one coil of the that illustrated herewith which was de- or continuous current, such as that from transformer. The sounding lever of the signed and built by Harry Rosenttial, an a battery. But here is one that clicks away transformer, fulcrumed on the center or electrical engineer of Xew York City. common leg of the laminated core of the The applications of these instruments are transformer, is alternately held in contact numerous a few of which are here men- with adjusting screws kept continuously

tioned : X-ray work, high frequency, Tes- magnetized by a permanent magnet. The la and cautery currents of all intensities. function of the magnet is to prevent chat- Ozone generation for liquid saturation ter and hum of instrument and renders the apparatus for the production of mechanical telegraphic sounds uniform. vibration and air suction for skin treat- The small transformer case (including ment; also, the apparatus for the produc- secondary voltage regulator) measures 3x6x tion of a remarkable new therapeutic ray, Ayi inches high. This transformer is ca- namely, the Rosenthal R-ray. pable of operating fifteen or twenty sound- The construction of such an equipment ers simultanecvusly. Energy taken by the

requires a fine degree of engineering skill, sounder is approximately four watts : the considering the numerous apparatus to be magnetizing energy taken, by transformer fitted' into the smallest possible space. is so small that the primary may be left in Commencing at the top. of the cabinet, circuit continuously, as the ordinary inte- the two X-ray terminals will be noted, grating watt hour meters will not indicate which are used to connect with the the energy coiisumed. X-ray tube. A milliampere meter The function of the contacts on is stationed on the left, which is trans-former is to adjust voltage to used for measuring the current best operation o-f sounder. I'nder sent thru the tu1>e when in opera- proper conditions it is practically tion. The control switch-board impossible to tell whether the consists of two white mar.ble pan- sounder is connected to an alternating or direct current circuit. .A. els. Vario,us binding posts are a- railway tele- placed in front of the panel, each trial equipment in That Actually pur- Somethiiin New in Telegraph Sounders—One graph office has operated success- pair being used for a defmite Alternating Current From Works Efficiently On Low Voltage fully on a sixt\- cycle circuit, hut pose, and the connections are made a Step-down Transformer. equally as vvcll thru flexible copper conductors. the device operates on twenty-tive cycles. Levers and switch arms are stationed at a merry pace on alternating current! ivithout any change is obtained by a move- about the panel suitable for controlling the In brief, the current from the line thru the A loud, clear sound S'llTin inch of the leveV. many kinds of currents supplied. The two main line relay keeps the arnuiture norniall" ment of but l84 THE ELECTRICAL EXPERIMENTER July, IQ17

A 36-INCH SPARK TESLA COIL ELECTRIC UNA-FON MAKES keyboard is connected thru a ten-foot flexi- FOR LECTURERS. MUSIC TO BEAT THE BAND. ble cable. Probably the most amazing and spectacu- The electric L'na-Kon here illustrated is electric musical instruments such as the lar of all electrical apparatus is the Tesla played from a keyboard, the keys of which Xylophone, Marimbaphone, etc., as these or High Frequency Coil and no electrical are exactly the same as those of a piano. can be played from the same keyboard. .\o previous experience is necessary for its The third unit of this instrument com- successful use and any piano selection can prises a small, light battery case for hold- be played on it, both harmony and melody. ing dry cells of standard size, wliich is The instrument is said to mark a new de- :onstructed with fastenings so that it may parture in tone quality, it having been lik- be attached to any part of the machine that ened by some to the I 'ox Humana of a is found convenient. The three parts of the pipe organ. The Una-Fon may be played apparatus are connected by a single ca- either soft or loud and is equally adapted ble, of such length that the whole apparatus to use in theater or in the open. In street can be instantly attached to any of the work, tinder fair conditions, it may be heard standard instruments now in use.

several blocks ; it has wonderful volume and carrying capacity. On the water its clear, RADIO IN DENMARK. brilliant tone carries great distances. The Denmark has organized at Svenborg a maintenance e.xpenses is kept at a low fig- school of radiotelegraphy with the ob- ure by reason of the storage battery sup- ject of giving complete professional in- plied with each set, cutting the operating struction allowing pupils to obtain the cost down to two or three cents an hour. necessary certificate to operate wireless Each tone-producing unit is a patented stations. special alloy, nickel plated, concave steel bar, mounted over a special resonator on a LARGEST STORAGE BATTERY IN solid oak frame, with an electric playing UNITED STATES. action attachment. It remains in perfect The Detroit Edison Co.. has in service adjustment, produces a fast vibrating stroke in its Congress Street Sub-station the larg- and wields a large composition mallet that est storage battery in the United States. brings out the full beauties of the tone. The This installation is of interest, not only instrument is not affected by atmospheric on account of the high capacity of the bat- 3 Kilowatt Tesla Coil in Full Activity, Giving 36 Inch Sparks. The Sparks May Be Taken conditions, and retains its tone at all times. tery but also as showing the most recent Into the Body as Their Ultra-high Fre- The various electric actions are firmly practise in storage battery engineering as quency Renders Them Harmless. This Is aj,plied to urban direct current lighting the Class of Apparatus with Which Our Pseudo-professors of the Stage Are Wont to systems. Over-awe and Mystify Us. This battery is kept fully charged and connected to the bus bars at all times in laboratory or lecturer's outfit is complete order to insure against an interruption of without such an equipment. It is most as- fc.rvice. In case of failure of the custom- tonishing to be able to draw coiling, flam- ary sources of energy the battery is in- ing sparks from a few inches to several stantly available for use. feet in length from j'our body to the coil The 'batterj- consists of ISO large E.xide without the slightest injury or discomfort. 'M^^^^Hjat cells having a capacity of 25,200 amperes Hundreds of other interesting and strange at 110 volts for one hour and 80,000 am- experiments may be performed, such as peres fc^ ten minutes. lighting large numbers of vacuum or Geiss- Elaborate endcell switches and battery ler tubes of various brilliant colors bj- control switchboard are employed for prop- merely holding them in the hand near the erly switching in the ce!!s, charging them coil without any wires whatever. The or- A Novel Electric Musical Instrument and regulating the counter electro motive Which Is Played from a Keyboard Ex- force of the battery. dinary incandescent lamp will glow with a actly Like That of the Piano. pale green light when held near the coil or Many of the largest central power sta- connected to it. Various minerals and tions are equipt with storage batteries sim- many precious stones will glow and fluor- mounted on solid oak cross-pieces on nick- ilar to this one, for the purpose of helping esce with unusual lights and colors under el plated floor rack that occupies minimum to carry the peak load, which may last its influence. Its sparks when occurrii.g space and can be moved anywhere. The onlv an hour or so, and which does not over large flat areas produce a large quantity of ozone. A wire bent in the shape of the letter "S" and balanced on the point of a pin from its center, will rotate as a static motor with flames shooting from its ends, when the pin is connected to c^e pole of the machine. .•\11 of these experiments and hundreds of others may be performed without the slightest danger, as the frequency of the current is so high as to render it harmless. Vou cannot even feel the spark if it is allowed to jump to a piece of metal held in -the hand, but where the spark jumps directly to the skin it gives a slight pricking sensation only on the spot where the spark strikes. The coil has a movable contact on the primarv for tuning it to the secondary. Proper tuning between primary and secondary is important for satisfactory results. The Tesla Coil rated at H K.W. will give a purple flame about' 9 inches long when operating in proper iune or resonance, and when the electrodes are separated to a greater distance each is surrounded by a fan of coiling sparks several inches in length. It requires a condenser of approximately .01 M.F. The coil shown in full activity is producing 36-inch high frequency sparks and is excited with a 3 K.W. radio transformer. The Gigantic "Standby" Storage Battery of the Detroit Edison Co., Said To Be the Largest Storage Battery in the United States. a spark gap and a high-tension condenser of .03 microfarad capacity. These outfits operate 110 volt. from 60 cycle -X.C. cir- Special octave couplers produce a twen- warrant the installation of additional dy- and cuits form an excellent apparatus for ty-piece brass band volume. The detacha- namos to carry the mean average load, plus the lecture and stage platform. ble keyboard enables the addition of other the peak load. : :

July. 1917 THE ELECTRICAL EXPERIMENTER 183

GRAFITE-SELENIUM CELLS. justed to within one-twentieth of one per A VERTICAL TABLE FAN. The new ty|)e of Selenium Cell here il- cent accuracy. Each unit will safely carry The advantages of the new electric table lustrated aiul hrouKht out in I'^nKland. pos- a load of 2 watts which will produce a tiiial fan shown in the accompanying illustration sesses distinct advantages over all for- temperature rise of SO'C. lie in the fact that it can be used on a mer types, chiefly owint; to the use of tl'.e These resistance units will be found of dining-room table or a flat top desk without non-oxidizalile grafite in place of copper, great convenience for obtaining any desired disturbing the pa- gold or platinum for the electrodes bridged resistance value. (The desired value is pers or articles over by the selenium. quickly obtained by series, parallel, or on the desk's or series-parallel These cells are combinations of the units) : table's surface. for a is claimed to have great shunting galvanometer to make it The breeze dis- critically damped, or to sensibil- tributed in a strata staliility, and should, reduce its with proper treatment, ity; making up the ratio coils of a slide- of about one foot remain effective for wire bridge or a Kelvin double-bridge: mul- above the table many years. As no tiplying the scale of a voltmeter or watt- level, and has a meter by increasing its resistance: radius of six to wire is used in their building construction, short-cir- up a "volt bo.x" to use in connection with a ten feet. There- fore, cuiting is excluded, potentiometer and for building up resist- everyone seated within that 'i'licir etticiency, meas- ance combinations to teach students to cal- radius, receives ured by the useful current obtainable culate and measure the same. a continuous breeze on illumination, is well above that of the A PRECISION TYPE OF RHEOSTAT. instead of the in- best previous types. This claim, put into termittent and figures, is as follows It is often desirable in electrical work, often annoying With a sensitive selenium surface of 5 especially when making delicate measure- Table Fan for on ments, to have available a finely adjustable strong blast of the Use sq. cm., and a voltage of 20, the additional or Li- ordinary oscillat- Dining-room current obtainable at various illuminations brary Tables to Give ing fan. All-around Breeze. is as follows 1 metre-candle H milliampere 50 metre-candles 1 milliampere ELECTRIC TAG MARKER SAVES 500 metre-candles 2 milliamperoN TIME. the The cells are constructed under su- The marking of price tags in dry-goods, pervision of Dr. Fournier d'Albe, A.R.C. and department stores particularly, is a the inventor of the Type-reading Sc, Op-' slow and tedious task if done by hand. tophone, and are made in two standard The simple motor-driven tag marker shown .\, suitable for patterns. Type working changes all this. By its use 2,400 tags can relays: resistance about 10,(XJ0 ohms. Type be printed in an hour. B, suitable for use as Pliotophone Receiv- The mechanism of this tag marker, for otiicr applications intermit- ers, or of which is driven by a 1/20 h.p. motor thru tent light: resistance about 100,000 ohms. a worm and gear, consists of a set of Type .\ has a sensitive surface of 5 s(|. cams, which move an endless chain of cm., and is guaranteed to yield the currents aluminum trays beneath a miniature type above specilied. Type B has a sensitive chase. The tags are printed as they move surface of 0.3 sq. cm., and is guaranteed along on these trays. The trays are hand to detect an intermittent illumination of fed. .\ tag is placed in each tray beneath 25 metre-candles with a sensitive telephone a clip which holds the tag in place from receiver and a battery of 20 volts. Larger the time it is fed into the machine until patterns are constructed by special ar- marked by a downward movement of the rangement. The size of standard cells is type cliase. This insures uniform regis- 2x2x1 inclies overall and weight 2] 4 ounces. ter of tlie marking. When the tag is RESISTANCE UNITS. printed it is automatically released from HANDY the clip and discharged from the tray at Something every electrical man wants at the end of the n:achine. some time is a standard resistance unit. The machine will accommodate any size Each resistance unit of the type illustrated or shape of tag up to l-'4 inches wide, of is mounted in a block of hard wood with A Precision Type of Rheostat of Par- any thickness from thin paper up to cards shellac finish. The terminals of the resist- ticular Value in All Fine Electrical 3/32 inch thick. The type chase is ad- ance are attached to spring binding posts. Measurements. justable to adapt it to various sizes of The resistance unit blocks are l-j4 inches type and is capable of marking as many square and 2,' j inclics high, and can be ar- as seven lines with fifteen small characters ranged togetlicr like blocks in various com- resistance such as the one illustrated. This or nine large characters on a line. The binations. The resistance wire is wound particular rheostat is of English manufac- type commonly used is of metal, full twelve bililar on a large diameter spool which is ture and comprises a metal tube covered point (',', inch high). With the usual set concealed in the block. All units are ad- with insulation and over which many turns up of the chase, it is possible to print both of closely wound bare resistance wire are the tag and the stub with the words Lot, placed. Si~i', Price and some other word if needed. By means of the usual hand wheel projecting at the right and the geared worm, it becomes possible to move the adjustable spring contact very accurately along the resistance coil. In order that this movement shall not require too many turns of tlie hand wheel, tlie pitch of tlie thread on the worm shaft is ipade quite long or about one-half inch, particular precision rheostat trated is designed to be mounted on the rear of a switch-board panel and the regulating knob or wheel only projecting thru on the face of the panel. It should prove ideal for all kinds of electrical measuring circuits, as well as wireless circuits. The Electric Tag Marker Prints 2.400 Price or Other Tags an Hour. The new battleship Ten- of Resistance portable, New Form Handy nessee will use 27.500 electrical horsepower, This tag marker is compact, Unit. It Is Supplied In Any quiet in operation due to the worm Size Desired. enough power to furnish heat, light and vcrv power for a city of 100,000 inhabitants. drive, and only weighs 45 pounds. 186 THE ELECTRICAL EXPERIMENTER July, 1917

III1IIIIIIIIIIIIIII1III1IIII1II iiiiiiiiiiiiMiiiiiiiiiiiiiMiiMiiiiiiiiiiiiiiiiiiiMiMiiiiiiiiiiiiiiiiimiiiiiir Notice to All Radio Readers

As most of our radio readers arc undoubtedly az^'are, the I'. S. Gofcnuueiit lias decided that all Amateur, Wireless Stations, xvhcther licensed or unlicensed, or cqiiipt for receiving or transmitting, shall be closed. This is a very important consideration, especially to those v.4io arc readers of THE ELECTRICAL EXPERIMENTER, for the reason that ice desire to continue to publish valuable articles in the tvireless art from time to time, and which may treat on both transmitting and receiving apparatus. In the first place, there are a great many students among our readers who will demand and expect a continuation of the -usual class of Radio subjects, which we have publisht in the past four years, and secondly, there ivill be hundreds and even thousands of new radio pupils in the various nazal and civilian schools thruout the country, who will be benefited by up-to-date wireless articles treating on both the transmittiinj as well as receiving equipment. Therefore, and in t'it'it' of the foregoing e.vplanation, zee feel sure that every reader zi'il! thoroly understand that alllw articles on transmitting, as well as receiving, apparatus may appear from time to time in tliese columns, he is not permitted to connect up any radio apparatus whatsoever to any form of aerial.—The Editors.

Testing Radio Units With Dummy Antenna By FRANK C. PERKINS

'' AHE accompanying illustrations, are likely to disturb the ether for hundreds Sixty-four kilovolts driving 250 amperes I figures 1, 2 and 3, show the equip- of kilometers in all directions. A need in quadrature would develop 16 megawatts I ment used for testing radio units of arises, therefore, for a dummy antenna, or of reactive power. -*- the Federal Telegraph Company a radio load for testing radio generatc-s, It is pointed out that an active power with a ihiinmy Antenna, as utihzed which shall not seriously stir up and vex rating of 200 K.W. woidd thus only de- at the Palo Alto, Cahfornia, laboratory. It the ether in the vicinity. The problem is mand a little more than 1 per cent of dissi- was possible, with this antenna, to repro- to load the generator but to suppress the pation factor. It is evident that this dum- duce practically anj- antenna found in com- output beyond a short ran,ge. This is a my has large dissipation possibilities. In mercial radio telegraph stations, and there- problem in radio inellicienc)-, and is just making radio units of larger capacity than have heretofore been attempted, it was found necessary to provide a dummy antenna which could be used for testing Fed- eral-Poulsen Arc converters of various sizes. Because of the large units contemplated, and since interference with nearby commercial stations had to be avoided, the type of construction shown in the accompanying illustrations was developed. It ma}- be stated that this af- forded capacities up to 0.031 microfarad, and by being of such construction as to have a low effective hci.ght, caused a minimum of interference. The antenna consists of five parallel layers of wires spaced 5 ft. apart vertically. The wires in each layer are 2 ft. apart horizontally and there is a 10 ft. clearance between the ground and the lowest point in the bottom layer. The bottom layer, which is grounded, is 136.5 ft. wide, with The Accompanying Views Show a Colos- a maximum length of 262.5 ft. sal "Dummy" Antenna Erected by a Large Radio Concern in Palo Alto. Cali- It is of interest to note that fornia, for the Purpose of Testing Out the other layers, insulated from Poulsen Arc Generators Large Now Being ground, are 20 ft. shorter and Extensively Used by Uncle Sam. The An- tenna Is 262.5 Ft. Long by 136.5 Ft. Wide. 41 ft. narrower. The insulated la\ers have fifty-one wires each and the grounded layer sixty-six fore observe the performance of the wire- the reverse of the ordinary problem of the w'ires. The two outer wires on each side of less sets under practical operating condi- radio engineer, which is to load his gen- the four top layers are size No. 2, because tions. eratdr as efficiently as possible, so that the the edge wires are not shielded as well as The Arc Radio Transmitters are now effects may be manifested at a great range. the others and it was desired to prevent the produced for commercial uses in ratings The dummy antenna at Palo Alto con- corona which would otherwise appear at the from 5 to 500 kilowatts, and the 350 K.W. sists of a series of horizontal galvanized edges of these layers. With this exception. unit has an overload rating of 500 K.W. iron wires in five layers, so arranged as to No. 14 galvanized telephone wire was used It is pointed out that wlicn electrical en- be capable of forming an air condenser of in all layers, and the wires are fastened at gineers test a dynamo they are not likely adjustably variable capacity up to about each end to 1-in. stranded caliles. Altho to disturb •engineering operations in otlier one-thirtieth of a microfarad. With such galvanized wire is not generally considered buildings, or even in other parts of the a capacity carrying 250 amperes, at 20,000 good practise in radio work, it was never- same building. When, however, they test cycles per second, the voltage, neglecting theless used on this antenna because with a radio plant of considerable power they all losses, would be approximately 64,000. the large number of wires employed the July. 1917 THE ELECTRICAL EXPERIMENTER 187

resistance could be kept within the usual lenîth so as to secure the paraliolic curve San Diego, Pearl Harbor and Cavite. limits. in the l-in. cables. Two short posts, For convenience the five parallel layers exactly 200 ft. apart, were set up on the RADIO IN PERU AND SPAIN. of the antenna are numhered from the top site with several intermediate stakes be- Measures have been adopted by the Peru- down. Layers Nos. 1 to 4 inclusive are tween. The wire was unwound from the vian Government authorizing the construc- well insulated, and a lon.e length of halyard reel near one of the posts and run out with tion of a teleîraph line between the cities fii lea and Castrovirreyna at a cost of 6,300 I'eruvian pounds ($30,659), and the installation of wireless stations at various points in the basin of the Amazon at a cost of 10,(X)0 Peruvian pounds ($48,665). El f'cniaiia also notes that a new telegraphic code has been compiled by the Department of Telegraphs and Mails, and a commission )f Government officials has been appointed to e-âmine the code and to make a recom- mendation as to its adoption. The new postal building at Madrid, Spain, is to be fitted with wireless telegraph and telephone apparatus of the latest pattern. The transmitter will be of the same type ;is that which made possible the transmis- -ion of the human voice from New York to Honolulu and Paris. From the central tow cr, 90 metres hii;h, wire will be stretched to the three other posts, of which two arc on the front and the other on the back of the building. The receix ing apparatus will com- prise a certain type of telephonic relay allowing the intensity of the feeble current received to be amplified 500 times. WOMEN RADIO OPERATORS TO THE FRONT. The National League for Women's Ser- vice has enlisted its first wireless operator. She is Miss Helen Campbell and Wonderful Night Photograph of Dummy" Antenna m Full Activity. Note the Corona she is an expert in receiving and sending. Glow on the Wires Caused by a Charge from a 300 K.W. Federal-Poulsen Arc Generator. She entered the service of the League on May 8th. Women in all parts of the coun- between the insulation and the supporting a "come along'' grip to the desired length try are taking up the study of telegraph towers was provided in order to permit of bevond the second post. and radio operating in earnest, as these putting in more insulation with suitable There was steel tape with its zero on the vocations hold undeniable proinise for those corona shields in case this became neces- second post stretched out beyond it with aspiring to fill positions of responsibility sary at a later date. Obviously, if this the wire and the end of the were done, only layers Nos. 1 and 5 could wire was placed at the exact be used, because the large diameter of tape reading before signaling. shields necessary with such a long string Having the end of the wire of insulators would otherwise interfere, the held firmly in place on the tape, layers being only 5 ft. apart. a man near the reel put It will be observed that provision was steady tension in the wire also made for the installation of corona by means of a "come along" shields on the insulator strings now used, grip until the wire was just but no trouble of this sort has been experi- raised above the intermediate enced thus far and these shields have not stakes, and then, upon signal been added. Beneath layer Xo. 5 are two from the man at the tape, the single wires which are normally connected wire was cut with pliers at the and have a separate lead running into the first stake. After cutting each laboratory. These have a capacity of 0.002 individual wire the crew, con- microfarad. By various combinations of sisting of two men at each these wires with different layers of the end, proceeded at once to fas- antenna, a considerable number of capaci- ten it in place on the l-in. ties are available, the maximum being ob- cable which had been previous- tained when layers Xos. 1, 3 and 5 are ly stretched, to remove twists, connected as the earth side of the system- and laid out on the ground in and Nos. 2 and 4 are connected with the position for hoisting. In cut- two single wires as the high potential side. ting the wires. 1 ft. over and With this combination the capacity is 0.031 above finished dimensions was microfarad. allowed for connections. The jumpers used for connecting the There was then a point 6 in. various layers consist of lî in. copper tube from each end measured otT provided with suitable clamps and fittiufjs with a rule, and this i)oint was so that shifting to different capacities is an kept at the inner side of the easv matter. The capacities most com- cable while the end of the wire monly used are 0.006. 0012, 0.017 and 0.024 was given two turns around the microfarad. Many others are available. cable and sufficient wrapping to Before deciding upon the exact lengths of secure it. The antenna as a the antenna wires, it was noted that with whole reaches the corona point evenly spaced crjual loading the l-in. cables with an undamped high-fre- to which the wires are attached would as- quency current of 250 ampere- sume a parabolic curve. The lengths of the at a frcfiuency of 20,000 cycles. wires in each layer were calculated accord- The accomjianying night photo- ingly, and thus a uniform tension is secured graph. Fig. 3, shows a layer of in the individual wires of each layer with- the antenna at the corona noint IVIiss Helen Campbell Has Successfully Mastered the out excessive pull on the pole supports. during the test of a 300 K.W. Intricacies of Radio-Telegraphy. She Is an Expert in Prexious to the tests, it was desirable to Federal-Poulsen .\rc genera- Sending and Receiving Radio Messages. tabulate the length of each wire, which was tor. The dummy antenna was calculated to the nearest 0.01 ft. A con- used at the laboratory for testing the high and service to the Nation. Besides, there venient scheme was tlien devis-ed for cut- power anparatus which the company has will be plentv of opportunities after\the ting the large number of wires to exact constructed for the United States Navy at war for radio and telegraph experts. — — — —

188 THE ELECTRICAL EXPERIMENTER July, 1917

HOW THE GOVERNMENT SEALS U. S. CALLS FOR TELEGRAPH AND "Telegraph operators in the army and RADIO APPARATUS. RADIO OPERATORS. navy occupy preferred positions both as Uncle Sam's radio inspectors have been The wars demand for telegraphic com- to rank and pay. Young men who take extremely busy the past few weeks seal- munication has increased so much that an up telegraphy, but who do not enter the emergency call has been Government employ will still render pa- issued thru the War triotic service by relieving those who de- Department for young sire to enlist. men and women of the "The tremendous demands upon the country to present operating forces of the country during themselves to be trained as telegraph operators. A HUMAN RADIO OUTFIT! Arrangements have been made with the Western Union Tele- graph Company to train 2.500 n e w operators. These are to enable the Government to handle its war telegraph business without taking any more operators for the Signal Corps from the present railroad and - commercial t e 1 e graph forces, and without seriously interfer- ing with vital communi- cations. The War Depart- ment's appeal fol-

lows : "Several thousand young men and women are needed for telegraph service, either in the Signal Corps of the army, or to replace those in commercial work who are leaving positions to join the colors. These young people must be trained. For this purpose the \\ estem Union Tele- Radio Fiends and Bugs has Please Take Notice of the Master Incarnated graph Company Wireless Vampire. This Photo, Which Came placed its facilities at to Us Anonymous— by Wireless of Course 1 & Herbert. N. the disposal of the Gov- Shows How the Fiend Is Gradually Turning Uncle Samuel Seals Up Wireless Apparatus Tight When He into a Radio Outfit. His Legs Already Are Our ernment to train twen- Does the Job. A Heavy Wire Is Run Thru All the Binding Posts Long Switch Levers, and Before We Go to and Sealed as Shown, and Woe Be Unto Anyone Who Maliciously ty-live hundred oper- Press. His Brain Probably Will Have Turned Breaks the Seal. ators, and the training into an Ether Wave! Here at Last We Have a Radio Enthusiast Who Loves His Set Well ing up all radio apparatus not in actual will be conducted by its experts. Enough to Get Married to It! use by the Government. "It is estimated that there are more wireless (sending) this period of intense activity the Hea\y wire is wrapt around the poles than 30,000 amateur — all and ener- of the spark gap and the ends of this operators in the United States. These mobilizing of the resources people wire are joined with wax bearing the great j-oung men now have an opportunity gies of the American —have taxed lives telegraph forces to the ut- seal of the United States of America. perhaps the only opportunity of their the present Heavy prison penalties are provided for —to contribute materially to their country's most and necessitate the immediate recruiting of volunteers for this the breakage of this seal. The wire short- welfare in an hour of need by volunteer- hundreds of service. telegraph circuits the spark gap and makes it impos- ing for this work. At the same time they The Government needs operators for its Signal Corps. sible to secure a spark. The impression will be mastering a trade in which stable be secured "Amateur wireless operators, women of the great seal is made in red wax on employment can almost always an ordinary piece of paper. in any important city. typists, and all other competent young men and women possessing MANUFACTURING the fundamentals of grammar WIRELESS APPARA- and high school education and TUS FOR SUBMA- not already employed in service RINE CHASERS. contributing to the national welfare, are urged to apply to the Radio manufacturers arc- now working night and da>- offices of the Western Union building apparatus for the U. Telegraph Company to take up telegraphy training. By so doing S. Xaval vessels. The photo shows quenched spark gaps they will serye their countr>- in being machined. a ver>- practical and patriotic These spark gaps are bras? wav." discs with silver centers, and thev must be accurate to CORRECTION NOTICE! 1/10.000 of an inch. Measure- ment is made by the small In the article appearing in the dial above the pin which Mav issue and entitled "Receiv- shows the accuracy. If the ing" the Marconi 300 K.W. Sta- spark gaps are inaccurate they tions on the Oscillating Audion," must be sent back to be ma- by S. Curtis. Jr.. an error was chined to the proper dimen- niade in stating that Dr. White sions. Sixteen of these discs of the General Electric Com- are installed in each set for pany's research staff had suc- submarine chasing purposes. ceeded in getting an Audion t>'pe of oscillator to operate at wave A new radio station has re- lengths as low as li meter. This cently been erected at X'iacha. should have read 6 meters, which wave length of oscillation was near La Paz. Bolivia. Com- FlKto by Kadcl & Herbert mercial .service was estab- only obtained with a perfect Manufacturing Quenched Spark Gaps in New York City for U . S. Naval non-gaseous bulb. lished on Oct. 20th. Vessels. The Gap Plates Must Be Machined to 1 10.000 inch Accuracy. July. 1917 THE ELECTRICAL EXPERIMENTER 189 How Radio Brought the Ne\vs to the Farm

WEATHER reports, market quota- Farmers who live near Mr. Banks did not east and west. Passers-by who would stop tions and world news daily by have to wait for the belated newspaper at the Banks' home to read the bulletin wireless telenraph, sucli is the which the K. F. U. carrier delivered to see board, or to inspect the wireless plant, innovation which makes the farm what the weather would likely be the ne.xt bought honey and thus came to be regular

and the work of Archie Banks, few hours ; they were not caught unprepared customers of the apiary, adding to a side- of Delmar, Iowa, of more than ordinary in- by any sudden and unpredictcd change in line income, which has already begun to as- terest. Tlie last vestit;e of isolation and temperature; a minute at the rural tele- sume large proportions. There was no aloofness from the world has been banished phone, to secure proper connections with thought of the business possibilities of his from the farm by this young lowan. Back the Banks farmhouse, and the weather fore- wireless service when it was first inaugu- of his achievements lies a story of deter- cast was known by them as promptly as it rated, but there is a close connection be- mination which should be an inspiratiim to was known by the man in all. the city, with the daily Eight years ago Archie Hanks was a six- ])aper laid on his desk but teen-year-old boy, living on the farm of his a few minutes after it had father, a well-known live stock farmer. The left the press. boy had always been interested in machin- This is not all, however. ery and mechanical matters, l)ut met with ."Vs one drives toward or little encouragement along this line from from Delmar, along the his parents. He might never have had an road which leads by the opportunity to develop his latent talents had Banks home, he comes sud- it not been for an accident. One day, in denly upon a large sign working about lier household task, the boy's stretched across the road, mother knocked off the telephone batteries. a board sign eight feet long "Central told her how to connect them and two feet high, upon up again and she did so," says Mr. Banks. which is painted, in large

"I happened to come in then and slie told words, this placard : "Eat me what she had done. Of course, I wanted honey, For sale here. To- to see if she did it right. I was promptly day's weather report by told to run along and that wdiat I knew about wireless on ne.xt curve. telephone batteries wouldn't bother anyone. Archie Banks." A few rods Well, I made up my mind I would know further on, at the first turn something about tlicni, and I set to work in the road stands the large studying everything I could get hold of- bulletin board, eight feet books, magazines and catalogs. In a year 1 had the house wired from cellar to garret, and lighted with electric lights run from batteries. Two years after- ward I had a small w'ireless built, but it would not work well. All I could do was to talk to Delmar, a mile away. I determined to do better, and so I set to work again." This second time the boy was more successful, so that today he has installed in the twelve-room farmhouse, a mile from Delmar and about eight miles from Now That the Country Is in a State of War and AM Amateur Radio Stations Are Ciosed, IVIr. Archie Banl

greatest task of the United transmitting set is seen on the right and the obtained with a primary excitation of & THEStates in the war against Germany is apparatus comprising the installation con- volts, obtained from a stora.ge battery. The that in overcominsj the under-sea sists of the followinj; and all of which are current consumed by the primary of the monsters, the SUBMARINES, which mounted on a Bakelite panel. The source spark coil is indicated by the two lower

have proven to he a constant and of high tension current for charging the meters ; the one toward the left indicates rapidl)- increasing menace to both the Allied condenser is derived from a special spark amperes, and the one toward the right, and American shipping. coil, stationed behind the panel. An inde- volts. The simple-pole double-throw switch below the two meters is used to throw in either 6 or 12 volts onto the primary of the

coil ; the latter voltage must naturally be derived from a 12 volt battery or other generating source. Terminals for the current source are located below the switch. The plug towards the right interconnects a key

with the coil as perceived ; while the plug on the left is employed for connecting the receiving apparatus with the antenna and ground, thru the change-over switch which is located directly over the voltmeter. The oscillatory circuit of the equipment consists of the secondary of the induction coil generating the high tension voltage which is used to charge a moulded type condenser, thru an inductance and a quenched gap discharger, the latter being visible in the center. Annular grooves are cut on the surface of the outside plate for rendering greater cooling facilities to the gap. A radiation ammeter is also furnished and this is placed on top of the panel. The receiving equipment consists of a standard cabinet outfit, with cr\stal detector which can be seen to the left of the transmitting panel. It is comprised of an inductively coupled tuner which has a fixt coupling coil, linked with a variable capacity for tuning to different wave lengths. This condenser is mounted in the center. A short and lontj wave change-over switch is employed and this is placed at the center upper corner. The detector is of the mineral type and is mounted below the condenser, while the buzzer, for test work is just below the detector. The complete outfit has been found to be very satisfactory and efficient and it will no Fig. 1 —Space Is at a Premium on the "Submarine Chaser." For Such Radio Service There Is Available the Extremely Light-Weight Transmitting and Receiving Set Illustrated. It doubt prove to be highly serviceable to Utilizes a Spark Coil with Independent Vibrator for Batteries. Uncle Sam's mosquito fleet. In addition to the excellent transmitter This problem is now in the hands of our pendent vibrator is employed and this is above described a very efficient and an all- most prominent scientists, inventors and mounted on the panel, and may be seen di- around receiving outfit has been designed marine experts, and one solution to this task rectly to the left of the antenna switch, and built by Messrs. L. G. Pacent and A. H. seems to have been found in the building of which is the right circular knob. A number Grebe for the submarine chasers, and this hundreds or even thousands of high-speed of important features are incorporated in outfit is illustrated in Fig. 2. This equip- armed motor-boats to be used in fighting this independent vibrator, ri:., a high-tone, ment consists of four units, viz., a main the U-boats. corresponding to a 500 cycle .generator, is tuning cabinet, loading cabinet, detector One of the most important details in equipping these "submarine chasers" is that of radio-communication apparatus to be used for notifying near-by vessels of submarine attacks and the like. The marked development in the art of radio-telegraphy in recent years has demonstrated that every vessel to be used for the above named work should and can be equipt with a suitable light-weight, yet highl.v efticient radio transmitting and receiving outfit. A considerable variety of such apparatus have already been designed and built and we give below descriptions of several types of transmitting and receiving sets which will prove very effecti\ e for the work in question. The accommodations offered by submarine chasers are few and for this reason the radio engineer must comply with the accommodations as much as possible before he undertakes the designing of the equipment. Space is a vcr\- important factor in consideration, and for this reason the apparatus herewith described have been chosen since they are of the most compact type ever built for the el1icienc\' which they have shown.

The first of these outfits is illustrated at Fig. 2—An Excellent Audion Type Radio Receptor for "Mosquito Fleet" Service, 1. set Fig. This was designed and built bv It Is Fitted with "Radiumiz ed" Dials That Glow in the Dark. Mr. A. B. Cole, of Xew York Citv. The :

EXPERIMENTER 191 July. 1917 THE ELECTRICAL cabinet, and an emercency crj'stal detector. A Medal of Honor to be Awarded by the Insti- The main timing cabinet is tbe largest of ibc tbrcc ami comprises an inductive coup- tute of Radio Engineers ler, coupled with variometers, the latter of which are controlled by two handles, while The Board of Direction of the Institute recognized standing and must be in actual, not necessarily commercial, operation, tlie center one operates a variable condenser of Radio Engineers has decided to award tho is to be given to linked in the secondary circuit. The handle annually a 'Medal of Honor" to However, preference widely useful inventions. on the left side is used to control the sec- such persons who have distinguished them- widely used and ondarv coupling. The two-point switches are employed for regulating the inductance of the primary of the inductive coupler. The cabinet on toj) of this is the loaduifr bo.x which contains the proper coils for aid- ins the regenerali\e .\udion circuit; the center knob is the coupIiTig handle, while the two side knobs are the inductance control handles. The cabinet to the right is the detector box in which the vacuimi detector is housed. An opening fitted with a slidnig Inil- door is used to note the illumination liancv of the detector bulb. The switch to the right is the filanicitt sw itch while the one to the left is the "H" battery control switch. A variable resistance is secured to the side of this cabinet (not shown here) and tliis is used for regulating the current consumption of the filament. The emergency crystal detector is hooked up to the set thru binding posts at the bottom of the main tuning cali^ inet. One of the most striking characteristics of this receiving outfit is that which has been overlooked by all of our radio engineers designing apparatus intended for warfare purposes. This is the application of the wonderful properties possest by radium of giving forth light when mixed with certain phosphorescent materials. .AH New "Medal of Honor" to be Presented by the Institute of Radio Engineers Each Vear to ttie of the graduated dials of tliis erpiipment Person Who, During the Two Preceding Calenda-- Years, Shall Have Made Public the Greatest are painted with phosphorescent radium Advance in the Art of Radio-Communication, paint which glows in the dark, and which facilitates working operations of the oper- selves by unusual advances in the fields of The advance may also consist in a scien- ator when he is ordered to have his den radio-telegrafihy and telephony. It has tific analysis or explanation of hitherto I'itth dark during certain engagements in been felt that some way should be found unexplained phenomena of distinct import- war. This will certainly be appreciated by whereby valuable work in these fields of ance to the radio art, altho the application the radio operator who has to operate this great and rapidly growing importance may not be immediate. Preference will be All connections of the vari- receiving set. might properly be recognized by an au- given to analyses directly applicable in the ous pieces of apparatus are made by means is well thoritative engineering society. As art. In this case also publication must be of square shaped aluminum wire which has of Radio Engineers, known, the Institute full and in approved form. been found to lie very eflfectixe for wiring here and with more than 1,000 member5_ The advance, furthermore, may consist purposes, as it is easier to wire and at the abroad, and -with sections in New- York, in a new system of traffic regulation or same time gives a better appearance to the Washington, Boston, Seattle. San Fran- control, a new system of administration finished instrument. It also reduces the cisco (with others in contemplation'), is of radio companies or the radio service weight. the leading technical and scientific society of steamship, railroad or other companies, The illustration. Fig. 3, shows a well- in the wireless field. It is therefore rec- a legislative programme beneficial to the built set designed by Cutting and Washing- ognized that a "Medal of Honor" from radio art, or any portion of the operating ton. This outfit utilizes a new principle in the Institute will be a goal worthy of at- features of wireless. It must radio transmitter design involving the use tainment by any investigator. or regulating publicly in clear and approved of a special spark gap, by means of which The appearance of the medal is as fol- be described represen- must, in general, be actually powerful oscillations and a hy-note signal lows : The front is a symbolic form and cases, marked are produced in a very simple manner with- tation of electromagnetic waves, indicating adopted in practise. In all out a transformer. The antenna wave the interlinking of the magnetic and elec- preference is to be given to advances made length can be changed with this set by alter- tric forces in their rapid path thru the in the preceding year. ing the secondary of the oscillation trans- depths of space. The reverse side bears The medal is to be awarded under the former only, the primary remaining fixt. the inscription: following conditions "To ,..;., At least thirty days before the April Distin- in Recognition of meeting the Board of Direction will call guished Service in Radio from a number of members and fellows Communication" ( followed of the Institute, whom it may choose to hy the date), the inscription- consult, for suggested candidates. This being surrounded by a lau- provision will be waived wholly or in part rel wreath. for 1917 only. The medal is the work of award, the Board the well-known sculptor. In deciding upon the meeting, thru those actually Edward Sanford, Jr., of at its April New York. present or voting. by mail, will nominate three can- The award w'ill be made at least one, but not more than yearly at the April meeting didates, in order of preference for the of tlie Institute to the per- award. The names of these candidates will son who, during the two then be sent to each member of the board, preceding calendar years, who will have the privilege of returning the shall have made public a vote for one candidate. Four weeks after advance in the greatest the .\pril meeting the ballot will be read, of radio-communication. art and the candidate receiving the most votes The advance may be a will become the recipient of the award. patented or unpatented in- The official presentation of the medal vention, but it must be com- candidate or his repre- adequately de- to the successful pletely and or June or sentative will occur at the May to scribed in a scientific Fig. 3— Particularly Efficient Radio Set Well Adapted meeting. "Mosquito Fleet" Service. engineering publication of — , -

EL. AMATEURS! ATTENTION!!

Now that we are for the time being, deprived of using our Radio outfits, it behooves us to become proficient in learning the Wireless Codes. Operators who know the Code are, and will be, in ever rising demand. The army and navy need thou- No. FX5I7 sands of operators right now. Can you qualify? Can you send and receive at the required speed, when your country Selenium Cells calls vou? Everj'bod.v has read about The Radiotone Codegraph is positively the only instrument made that will send such the e-\periments of telepho- unbelievably close imitation of a high pit ch Radio Station, that it has baffled experts, tography {sending photo- an graphs over a wire hundreds r's outfit, consisting of and sounder. The The outfit replaces the old-fashioned learne key of miles) made by Professor Radiotone Codegraph comprises our famous Radiotone High Frequency Silent Buzzer, a Korn and others. It Is also known that if the problem of special loud talking receiver with horn, and a key all mounted on a base. Operated on tele-vision is ever solved, the th e characteristic high pitch sound, which while one or two dry cells, the phone will emit selenium cell will play an im- not harsh, is heard all over the room. With little trouble you can learn the code correctly portant role. At present we are the only concern in in 30 days the United States selling these cells. They are the most sen- AND THAT IS NOT ALL: sitive ones made. Better send for a cell to- outfits together for intercommunication work and you and your Connect two of these day and try making an elec- friend five or fifteen blocks distant can converse over a NO. 36 WIRE, so fine that no one tric dog that will follow a lamp, or an electric burglar will see it. Or you can use instead of the wire, a metallic fence and the ground. Or you alarm. It's very instructive lighting line, using no extra wire, only the ground. Full can communicate over your 110 and great fun. (See Novem- directions how to do this are furnished with the instrument. DEALERS: This Is the 20th ber, 1916, issue "Electrical Century instrument that will sell like WILDFIRE. 600 sold in New York in 10 days. Get Experimenter.") our proposition today! No. FX5I7 Selenium Cell, Radiotone Codegraph complete as described, each, tfj l Qff «pi.;7»J Shipping \Vght., 4 oz. $6.00 IMMEDIATE SHIPMENTS IMMEDIATE SHIPMENTS BOYS! THE "ELECTRO TELEGRAPH" Here Are •fEilEGR'^pff'S'SDEs! the Stars LETTER5I MORSE [COHTIHEMT&L $122 and Stripes in All Their Glory. the Be TELEGRAM first one in ^^Bm your town to wear this p a t r i o tic

e b 1 e m . ) m 'Elictro" ^^S25 Think of it: An e 1 e c telegraph trically i 1 •

1 u m i nated boutonniere worn in the lapel hole of your coat.

It illuminates our National Flag in the original colors with a brilliant electric light, lust insert Flag in button- coat, put flash- hole of your "hl'''\"ot<>"'y practical, honestly built telegraph <)"<« light case in vest or coat is not « tov. but a By studMng tne sounds but works like the big commercial instruments pocket and every time you operator Such code for 30 days you can become a flrst-class 'fleKraPj! press the button, the flag in consists of TWO complete tele- operators are in big demand now. Outfit "« your button-hole flashes up graph instruments each measuring 3%x2%x2yj. AH met.al Pfrts rubber k"n*'^ with a beautiful color effect. highly nickel plated. Including key lever Note hard "''^J^'f-s^e'' Code Chart, telegraph blanks and coiinecting wire ,™™«^ graph 'nstru- but no batteries. Outfit works on 2 dry cells (one cell '"[. '=»^'' works """> wa>s, each ment). The "Electro" Is the ONXY Outfit (.hat (postage 10 Nothing to get out of order. Illuminated flag, cord and plug (to station can call: no switches, no extras. $.60 cents). I or money back. be connected to any 2 cell flashlight Oiiaranteed to please you $1.00 cord and plug, Price Complete as illustrated ^ Illuminated flag, flashlight case and battery, stores. .5"»"'^<'«8'" complete as per illustration. $1.10 postage Ijc). At all good dealers and department " Ji"V°' add mailing charges for two proposition today. supply you send us $1 do for outfit rind DEALERS : Write for our IMMEDIATE SHIPMENTS pounds, otherwise we ship express collect. THE ELECTRO IMPORTING CO. The "Electro" Rheostat-Regulator 'Electro" Pony Receiver

(Porcelain Base) Our Pony receiver Is This IllUBtratInn rppresciit« our little rurrent without doubt the best rcKutalor wlilch Is W«-<1 fveowht're to rt-Rulatc article for the money buttery current. It will prevent the burninK out to-day. III vnur battery lamps, or will reitulate the s|i«e«J Points of superiority : oSBihle Powerful per- to Kit out of order. It la coiistnicted ENTIRELY manent steel magnet, OF PORCELAIN, mcul and hard rubber. soft iron core, fibre coll The resistance of our Kh(y>stat la 10 ohroe, the heads, very thin dia- (ai)HclIy 3 anil)eres cunthiually, slzo Is 4 Inches In phragm, brass posts In- diuiiieter: thickness of porcelain base is 13/16 ins. side. Hanger can be un- No. FK5000 nheoslat Remilator. Price screwed and receiver ShiM'ing tveilfht, 2 lbs. $.60 will then fit our -Vo. IMMEDIATE SHIPMENTS AX8(j77 headbands. .SO.ME rsES. inninini7(r» — For ail telephone work. Also for making the small testinu' outfits for repair men in cir- No. HK 1800 cuit with only one dry cell or flashlight battery. When connected in parallel with your The "Electro" Radiotone house telephone receiver, you have a double receiver, an invaluable acquisition to those who HIGH FREQUENCY SILENT TEST BUZZER plione in noisy places or to people hard of hearing. It can also be used for wireless though its low resistance won't The RADIOTONE ts NOT a mere test buzzer. permit of such good results as a higher It infinitely more. H. Gerusback wiio de- resistance is Mr. phone. signed this instrument labored incessantly to This receiver is single pole: 2'^ilii Inches; wgt produce an instrument which would imitate the oz. 4 : resistance, r.") ohms. IF TWO OF THESE sound of a hiph power Wireless station as heard RECEIVER.^ ARE ISED, IT IS PdSSlHI.E TO in a set of phones. This actually has been .SPEAK AT A DISTANCE OF 150 FEET WITH achieved in the KADIOTONE. This instrument OCT r.SINV! H.iTTERIES ONT; WIRE HEINI; elves a wonderful hi^'h pitched Ml'SICAL NOTE SrFFMIENT IF GROI.Vl) IS ISEO «r» cn No. EKI024 Pony Receiver. . . . v'-'-O'-' in the receivers, impossible to obtain with the 75 ohm.^. ordinary test buzzer. The RADIOTONE is built No. FK 5000 IMMEDIATE SHIPMENTS alone entirely new lines; it is NOT an ordinary buzzer, reconstructed in some manner. The RADIOTONE has a sincle fine steel reed vibrating at a remarkably high speed, adjusted to its most eflBcient frequency at the factory-. Hard silver contacts are used to make the instrument last practically forever.

Yes. the RADIOTONE is SILENT. In fact, it is so silent that you must place your ear on lop of It to hear its beautiful musical note. You will be astounded at the wonderfully clear, ."iOO cycle note, sounding sharply in your receivers, when operated on one dry cell. To learn the codes, there is absolutely nothing like it. With the radiotone. a key and one dry cell and ANY telephone, a fine learner's set is had. Two or more such sets in series will afford no end of pleasure for intercommunication work. Particu- larly now that we cannot use our Wireless sets, the Radiotone Is already in wonderful demand. All the interestiuK things as descriiied with our Radiotone Codegraph, elsewhere on this page, can be performed with the Radiotone, a key, a No. B-2 No. B-7 dry cell and a phone. Each $0.15 Each JO. 10 Shipping Radiotone as described each Shipping 3),i7Cl Weight IMMEDIATE SHIPMENTS Weight IMMEDIATE SHIPMENTS 2 lbs. per doz. 2 lbs. per 12. These binding posts arc furnished either nickel plated or gold lacquered, They are made of first quality brass holes are ; accurately bored, well fitting set screws, and higlViv pollisbed. Each post is furnished with a % in. machine screw and washer (not shown In illustralilustrations). HERCULES DYNAMO Engravings are full size 71 >> The Electro The Livest Catalog in America Hercules is a dynamo generating 12 Volts, II Our big, new electrical cyclopedia No. IS is wailing for Amperes (Hiii you. Positively the most complete Wireless and elec- Wattsi and n trical catalog in print today. 200 Big I'ages, 600 marvel of elec- illustrations. 500 instruments and apparatus, etc. trical or me- Big "Treatise on Wireless Telegraphy." 20 FREE chanical effi- coupons for your ir>0-page FKEE Wireless Course ciency and sim in 20 lessons. FREE Cyclopedia No. is measures plicity. 7x51,4". Weight 14 lb. Beautiful stiff covers. LIVEST CATALOG IN It Is espe- "THE AMERICA" cially designed for lighting and charging storage Now before you turn this page write your batteries; will run 18 twelve volt lamps simul- name and address on marpin below, cut or taneously. Can also be u.sed as a powerful mo- tear out, enclose 6 cts. stamps to cover tor developing nearly % H.P. Machine is shunt mail charRes, and the Cyclopedia is wound; size 7 In. high, by 11% in. long and yours by return mail. 6H in. wide. It is the cheapest Dynamo for its ELECTRO IMPORTING CO output on the market. THE 231 Fullon Street, New York City, No. AGEK 1209. Electric Hercules Dy- namo; shipping weight. 40 lbs. Price $17.50

We carry these machines always in stock and can make immediate shipment.

31 FULTON ST., NEW YORK, N.Y. 1 —

194 THE ELECTRICAL EXPERIMENTER July, 1917 e?N5TRUQT2R n ( ( ^{ 1( 1( mli li II II w II ii ii II If II II 1 — — — — — — — — — — — — — — — —

An Improved Burglar Alarm Utilizing the " Stick Relay." By ALBERT H. BEILER

electrical experimenters noticed that once AI is opened, its subse- indicated in Fig. 3. Now temporarily re- MANYhave at one time or another in- cjuent closing teill not energise the relay move the entire armature from the tele- stalled a burglar alarm in their again, unless O is closed. graph sounder and file the end down half- homes. Most of the burglar Fig. 2 shows how this principle is used way. (Fig. 3.) Drill and tap a hole as indi- alarms constructed by amateurs in the burglar alarm. The relay instead of cated. Screw the piece B, on to it so as to are of the ofcn-circuH type, and have there- having only one front contact has two, one form a half lap joint. Insert adjusting fore several disadvantages, the most im- for keeping its own circuit closed as just screws with lock-nuts into the end holes of portant of these being, that, whereas the described, and the other to close a circuit B, and then replace the armature in its opening of a door or window causes the for ringing an alarm bell. The relay, which frame. alarm to ring, the closing of the door or by the way, is only wound to 4 ohms, oper- The small brass pillars A, should be window will stop the alarm again. To keep ates on 110 volts in series with a lamp or screwed onto the base in such a position up a steady ringing requires a different type lamps, which are connected in parallel with that when the armature is pulled down, the of circuit than that usually employed. This one another. Thus when the alarm starts, adjusting screws hit the centers of the may be of either the closed or open type. not only will the bell ring, but the lamps pillars. The screws must be exactly ad- In the former, the current flows continu- will light and assist friend burglar towards justed so that each makes contact with its ously and the opening of the circuit causes a hasty departure. The relay may be made pillar. If one is screwed down too far, the a relay to release its armature which touches to operate from batteries if the builder other will not touch its pillar or front the rear contact thereby ringing the alarm. desires to dispense with the lamps ; indeed contact. This should be thoroly tested by The latter type is an electric circuit. seen in the continu- The magnets when ous ringing bell, energized should with which most of draw the armature us are no doubt down so that both familiar. There is front contact circuits another open-circuit are closed. Lamps device, however, or bells may be used which is less known, to test the continu- called a stick relay ity of the circuit at arrangement. It is the contacts. this last one which T w o additional we shall consider in binding posts will be detail. needed as shown in Fig. The stick relay 4. The wiring on the instrument is used extensively proper is in the interlocking made as indicated. machines for railway signaling. Its The reader will mode of operation see the advantage of insures the follow- this type of burglar over the con- ing result : — a cir- alarm cuit may be closed tinuous ringing bell, at a switch but not because the alarm opened again at the may be immediately switch, same point ; it may shut off by a be opened at a sec- and be ready for ond switch but not another alarm an inclosed at this latter stant later, whereas point. To illustrate with the continuous this a little more ringing bell an clearly, let us refer armature must be to Fig. 1. lifted bj- hand and When the main the alarm reset. switch M is closed, A f e w auxiliarx- but the open circuit contrivances m a y

i n d o also be made in con- door or w w Working Drawings and Diagrams for Constructing a Really Reliable and Particularly switch O kept open, Effective Burglar Alarm Apparatus, Employing the "Stick Relay" Principle. Many Other nection with the no current can Applications of This Relay Will Suggest Themselves to the Experimenter. burglar alarm. The travel thru the simple burglar alarm relay, and its armature will be drawn away the same source of current that rings the may be set from inside the house. When from contact C by a retractile spring. If bell ma\' be used to operate the relay. a person leaves, and opens the door it will switch O is now closed, either by opening Since double contact relays are rather ex- ring, but stop when he closes it. This, of the door or the window, electro-magnet R pensive, a good substitute that will cost course, cannot be done with the alarm de- will draw its armature towards it. A then very little, will now be described. Secure a scribed herein, and a means must be em- touches C, and the current has two paths telegraph sounder (or the equivalent parts ployed to set the alarm after the person has is outside. to travel, i.e., one by way of the open-circuit from a large electric bell ; also the parts closed the door and The main door switch, and the other by branching off may be easily made), one wound for 4 switch may be put outside the house and at B, going tliru contact C and the arma- ohms is best if the lamps are to be used, closed when leaving, but this is sometimes ture, thru the magnet and back to the posi- also a piece of 5/16" square brass, 2!4" undesirable where there is no good means 1" tive main. Should O now be opened, it will long, and two pieces of ^" brass rod of concealment. have no effect on electro-magnet R, since long. The two pieces of rod should each The aut'ior has devised a little contriv- R still has a path by which it obtains its have a hole drilled and tapt about half-way ance wherein the alarm is set from the out- source of current. The current can only be thru them longitudinally. The 5/16" square side if/ieii the key is turned in the lock, in shut off by main switch M, but it will be brass should have holes drilled and tapt as conjunction with another device which rings : —

July, 1917 THE ELECTRICAL EXPERIMENTER 195

the alarm as soon as tlic key is aRain turned setting the alarm*. When the door is FLY PAPER. in the lock to open the door. not Thus only opend hy the key, A will move to the left Resm 8 parts will the rinj; wluii is alarm the door actual- without carrying the switch lever with it, Castor oil 6 " ly opened, Init tlie turning; of the key will thus insuring the continuity of the circuit, Glycerin 3 " 'i'hc knoh II is used for push- Dissolve the resin into the other two ing the knife back against A, mgredients by the aid of heat. When they when the door has been opened. become a liquid spread on parchment paper W hen the author installed his by means of a brush. alarm the greatest difficulty was to get people to set it. "MOSQUITO CHASERS." To prevent anyone forgetting Oil of pennyroyal 1 oz. " to close the main switch, a very Castor oil 3 simple but effective device was Alcohol 6 " linally resorted to, so that the Mix together and apply to parts of body alarm is ahways set, can be shut exposed to the mosquitoes and they will off it rings, still, when and a not bite or come near it. moment alter having stopt Contributed by ringing, it is set again. The ROBERT THOMPSON, Jr. main switch, instead of being a knife type, is a two-way snap switch, connected as illustrated the spool and tied or in Fig. 6. When the alarm pasted in place, fit- tmg length-wise with the spool rings and it is desired to shut centers and up along the inner side of it off, the switch need only be both flanges. The coil turned once. For an instant (for 110 volts D.C.) will require about 7 lbs. of Xo. tlie time it takes for the piece 20 gage wire, single cotton covered, C, to snap from contacts BE or 7 lbs. of Xo. 23 gage wire for 220 volts, D.C. to AD—the circuit will be In starting, about 1 ft. opened, which is enough time of wire must be allowed for for the stick relay's armature to a magnet lead which is past thru a hole near the center be raised. The switch is imme- of one of the diately closed again which, flanges. Each layer should be insulated with a heavy however, does not start the coat of thin shellac. When the winding alarm as previously explained. is finished, about 1 ft. of wire must be left for the other lead. The strips The reader can, with a little of tape can then be brought over and pasted ingenuity, arrange to have even together to hold the coil in shape and in- the turning of the door knob sulate it from the magnet body. Several start the alarm. This should turns of the tape are then wound around have a separate switch, how- the outside of the coil. The coil may then ever, so that it may be put in be left in a w-arm oven for about a day to operation only at night, whereas let the shellac harden. the rest of the alarm may be in The magnet leads are spliced to a piece operation all the time. of heavy lamp cord. A ;'.s inch hole should Since no circuit is directly be drilled in the top of the magnet casting opened or closed at the pillars for the Special Arrangement of Interlocking Switches for Con- cord and bushed with a fibffr in- and since consequently trolling "Stick Relay" in Burglar Alarm System Here no arcs sulating tube. The coil should then be Described. are formed, the of use platinum placed in the magnet body: if it has any contacts is unnecessary. play, several extra layers of tape can be wound on the coil to keep it start it. The reader can arrange to ring sufficiently * tight. tlie alarm by so much as inserting a key in The switch need not necessarily be the main The brass plate is then fastened in switch it may be any switch in series with the if place. the lock, he has a contact insulated from lint: the lock frame, and which will touch the To suspend the magnet, three equal frame by means of a circuit thru the key. lengths of chain are attached to a sup- This latter is simple, but the two formerly A i^-TON LIFTING MAGNET. porting ring: the loose ends are fastened to the screw eyes to keep the level. mentioned are slightly more complicated. An electro-magnet that is capable of lift- magnet The cord is then attached to a plug The bar A (Fig. 5j is pivoted to B, B is ing about 1.000 lbs., may be easily made. to make a connection with a 110 volt direct pivoted to C, while C is fastened to a base Its current consumption is about 5 amperes current M by pin P. If A moves to the right or on 110 volts. circuit. It is not adapted lor operation on alternating current circuits. left B moves to the right or left. The The body of the magnet consists of a cir- Contributed by movement of B causes C to travel in an cular piece of wrought iron or steel 7J4 J. LWAK. arc of a circle. The upper part of C en- inches in diameter and 2 9/16 inches thick. gages a stifT spring S, in its travel, but only The bottom of the body should be machined ' h/rought for a moment ; for when A has moved as true and a circular groove turned out in it ffo/e for cord. iron far to the right as it can, C will be in a to fit the magnet coil. The outer end of the position to the left of S, and S. which will groove is counterbored 1/16 of an inch L have ceased engaging C, will spring back deep by l-}4 inches wide, to fit a brass ring to normal. When A is moved to the left, which keeps the coil in place. The ring is C will turn clockwise, again engaging spring held in position by eight small flat-head S and carrying it to contact Q, causing it to screws. When fastened in place, the screws touch Q. This closes the alarm circuit; and brass plate sfiould be slightly below only for an instant it is true, but long the surface of the magnet body. enough for the stick relay to operate. To support the magnet, three screw eyes The part A is rigidly attached to the lock of 3/16 inch stock should be provided and lever of the lock, so that when the latter fastened in three tapt holes equally spaced moves, A will move with it. When the door in a 5 in. diameter circle, or one ^s inch is locked by the key, C moves counter- stock screw-eye may be placed in the cen- clockwise and engages S so that S does not ter as shown. For winding the wire coil. touch Q. Upon opening the door, however, a wooden form or spool must be provided. It S touches Q and the alarm is rung. These is made with a cylindrical core .>'_• inches parts should, of course, be firmly covered in diameter by I'j inches long and slightly over with a steel junction box attached with tapered, so that the coil may be easily re- blind screw's. moved when finished. The method for closing the main circuit The flanges of the spool are 7's inches in by means of the door key will now be de- diameter wooden disks fastened on the scribed. In Fig, 5, it will be seen that the cylindrical piece so as to be easilj' removed. upper part of A engages a bar which is The spool is mounted on an axle or between Something Everyone Finds a Need for at Some Time Is a Good Lifting Magnet. Here attached to the lever switch, K. centers, to allow it to rotate while of a When both Are the Details for Building an Efficient A moves to the right it will earn,- this lever winding the coil. About a dozen strips of i/2-Ton Electro-Magnet for Use on D.C. along with it. closing the main switch for insulating tape are equally spaced around Circuits. :

196 THE ELECTRICAL EXPERIMENTER July, 191 7 More About the "Perpetual" Electric Clock By HOWARD W. LEWIS

Chairman Stanford University Branch of .\. 1. E. E, THERE appeared in the June, 1916, (lulum rod is attached a flat link with a standard seconds pendulum costing several Electrical Experimenter, a de- hook on its outer end, which engages with hundred dollars. scription of a proposed perpetual the ratchet-wheel and turns it one-sixth The original design of "Perpetual Motion" electric clock and, in August of the of a revolution for each alternate stroke Clock involved the action of a swinging same year, an explanation of why of the pendulum. A copper leaf brush permanent magnet, which, as it swung into the same would not operate indefinitely. bears against the commutator from below. the coil, was supposed to develop sufficient That the plan is entirely feasible, provided When the plunger is moving away from energy to keep the clock going forever. a small amount of energj' be supplied from Upon request of the Editors, the author some outside source, may be seen from the made a quantitative electrical measurement following description and illustrations of a upon this device. For one thing he soon similar device recentlj' constructed at Stan- discovered that operating it upon batteries ford University. was too expensive, as it is now in con- In connection with some research work tinuous service eight, and often more hours in Aerodynamics, need arose for an in- per day. It is now operated thru the me- strument which would close a battery cir- dium of a bell-ringing transformer. The cuit momentarily secondary circuit at one second in- which it operates terzals. As a sub- is energized by

s t i t u t e for a batteries, how- standard seconds ever. pendulum, an The point was electro - magnet- raised as to the ically actuated magnitude of the clock was built induced current which is capable in the coil. of performing the In order to an- desired service swer this ques- very satisfaction the author torily. made a simple The photo- test which con- graphs show the vinced him that In Connection with con s t r uc tion Some Research the transient phe- clearly. The de- Work in Aerody- nomena referred tails may be seen namics Need Arose to are inappreci- for an Instrument from the draw- that Would Close able c o m p a red ing. The frame a Battery Circuit with either the Second In- is of small iron at One normal current tervals, the Appa- pipe and the table ratus Shown Hav- thru the solenoid, of thin steel ing Fulfilled the or the current in Requirements Very plate. The pendu- the secondary Satisfactory. A s lum consists of a a Test It Was (battery) circuit. round steel rod Run for 24 Hours These experi- with with two attached a Deviation ments were as of a Few Seconds weights. It is Only. follows hung on thin (A) Solenoid flexible steel entirely discon- springs from die nected from the short piece of angle iron shown, thus being the solenoid and the hook is consequently source, then connected directlj- to the ter- free to swing with a minimum of friction. reaching forward to pick up the next tooth minals of D. C. milli-ammeter. Xo effect The period, that is, .the time of one of the ratchet-wheel, this brush rests on a was produced on ammeter needle when the swing of a pendulum, depends upon its fiber segment and the circuit thru the coil plunger was rapidly moved in and out of length and the distribution of its weight. is open. On the return stroke, however, the solenoid. Same absence of effect noted Near the bottom of the pendulum rod is the hook pulls a live (brass) segment when telephone receiver was used as cur- a large iron cylinder (part Xo. 7) which under the brush and current flows into the rent detector. \'ery slight deflection when may be moved up or down. The upper coil, which thus exerts a powerful pull on sensitive ballistic galvanometer was used end of the rod is threaded to receive the the plunger. Before the plunger reaches as current detector. nut, 16. Coarse or fine adjustment of the the end of its travel, a dead ( fiber) seg- This is exactly what might be expected, periodicity is thus secured by shifting one ment rolls under the brush, the solenoid since there is no field produced by the or the other of these weights. releases its pull on the plunger, and the solenoid, as there is no exciting current On top of the plate is mounted a \'eeder pendulum swings back to repeat the cycle. thru it. I take it that what small current stroke counter, actuated thru links from The relative positions of the ratchet-wheel there is induced in the solenoid is due to the pendulum rod. This device, together and commutator are adjustable on the the rapid motion thru it of the minute with a stop watch, facilitates the calibra- shaft, so that the time of excitation of the remanent field in the plunger. However tion and adjustment of the clock. solenoid can be placed at any desired point as this is composed of a bundle of fine, A solenoid consisting of 2,700 turns of in the stroke of the plunger. An adjustable soft iron wires, this residual magnetism is Xo. 26 B. & S. gage insulated copper wire condenser of several microfarads' capacity very small. is attached to the lower part of the frame. is used to eliminate the spark between (B) Solenoid connectly directly (without To the bottom of the pendulum is fast- commutator and brush. ratchet wheel or commutator) to D. C. ened a bundle of closely bound iron wires. The secondary circuit, for whose opera- source; current in the circuit as indicated This curved plunger moves in and out of tion this clock was built, is closed once by milli-ammeter was 0.26 amp. Plunger the solenoid as the pendulum swings. The each cycle between a phosphor bronze rapidly moved in and out of the solenoid coil is energized from either the 110 volt spring and the pendulum. The duration of by hand. Effect : When plunger was lighting circuit w ith a lamp in series there- the closure of this circuit can be adjusted forced in, current decreases, while the with, or from 3 dry cells without the lamp. bv turning the screw (see details, part No. plunger was moving, about yi milli-ampere. It is necessary, of course, to have some 19). \\ hen the plunger was drawn out, current arrangement which will close the circuit Considerable time and attention was increased, ivhilc the plunger was moving thru the solenoid when the plunger is mov- given to designing this mechanism along about 'j milli-ampere. As soon as the ing toward it, and open the circuit when correct principles and it has been very plunger was stopt from moving, or as soon the plunger is moving away. Accordingly, carefully constructed. The results attained as it had moved out of influence of the so- a six-tooth ratchet-wheel is fitted on a justify the trouble involved. After a pre- lenoid, this transient current increment or short horizontal shaft, and a commutator liminary adjustment, a continuous run of decrement stopt and tlie current returned having the same number of brass and of 24 hours' duration showed a deviation of to its normal value in the circuit, as de- fiber segments of equal width, is placed be- only a few seconds from a standard clock. termed by Ohm's law, i. e., 0.26 amp. side it. The shaft is mounted in plain Furthermore, it closes the secondary cir- This again is exactly in accordance with bearings on top of the plate. To the pen- cuit at regular intervals, quite as well as a the theoo' involved, that h, when the July, 1917 THE ELECTRICAL EXPERIMENTER 197

plunder was movinj; into tlie solenoid the drawn out of the solenoid along a very containing crushed chalk should also be ihix threading the latter was increasing at similar line of thought. It is exactly anal- kept handy in case any quantity of strong a rapid rate, dnc to the decreasing reluct- ogous to the arc that follows the opening acid is spilled. ance of the magnetic circuit, tiie magneto- of a switch in an inductive circuit. The Contributed by H. J. GRAY. motive force meanwiiile remaining con- collapsing magnetic field induces a volt- stant. This cliange of llnx indnced a voltage in the coil wliich tends to maintain MULTIPLE TELEPHONE AND age in the tnrns of the solenoid which the current. TELEGRAPH "PHANTOM- tended to oppose the E.M.F., which was (O/ cuitrsi' if the moving core had been SYSTEM. forcing the current thru the coil; in other of steel, puiverfiilly }iHi(/neli:ed, the effects By L. R. W. Allison, Assoc, di noted would have been much more pro- A. I. E. E. - nounced. El).] words it is the well-known law L = . — dt The complementary relation between the telephone and telegraph is It is exactly analogous to the similarly system particu- induced coimtcr E.M.E. which arises in a WHAT TO DO WHEN ACIDS ARE coil to oppose the How of current therein SPILLED. when the coil is lirst connected to a source The safest course is not to spill the acid; of continuous voltage. Due to the tact, the next best is to apply an alkaline solu- ^lephooe however, that the movement of the plunger tion at once, or cover with chalk. It is could not under any conditions compare in a good plan to keep a jar of strong wash- rapidity with the rise of current in an ing soda solution always ready in case of inductive circuit, this counter E.M.F. is emergency. The reason for using a jar TekpAeoe

undouhtedly very much smaller than it instead of a bottle is that the solution can would be if the solenoid permanently sur- be poured over the spilled acid more rounded the core and the current were quickly. A loose cardboard cover—the lid ^e/eohane then estalilisht in the coil. of a box— will serve to keep out dust, and A moment's reflection will explain the more water can be added when necessary observed phenomena when the plunger was to make up for evaporation. A cocoa tin

Schematic Diagram Showing How Three Telephone and Eight Telegraph Messages Are Transmitted Simultaneously Over Two Telephone Circuits. The A. T. and T. Co.'s BCB Method. Steil spring ^^ larly interesting and instructive. The accompanying diagram shows the method of wiring for multiple telegraphy as arranged by the American Telephone and Telegraph Company, indicating two telephone circuits, totaling four wires, which provide for the transmission simultaneously of a ma.ximum of three independent telephone conversations and eight distinct telegraph messages without any interference with each other. The telephone circuit consists of two copper wires of approved construction, arranged in specific relation to each other and transposed at frequent intervals to reduce the inductive effects to a minimum. This pair of wires forms a metallic circuit, equipped with auxiliary apparatus, loa > fi1-')) poses by the two parties in direct communi- m -^3 • cation, during the period of connection, as will be readily understood. .t •.,* rron This complementary relation between the / 1 1 I .n tclephiMie and telegraph shows that telephone toll and li>ng-di

198 THE ELECTRICAL EXPERIMENTER July, 1917

A "GEISSLER TUBE" EASILY ELECTRIC IGNITER FOR FIRING above the spark coil, and be sure the wires MADE. A CANNON. are carefully insulated from each other. Now that Geissler tubes are hardly pro- After having some experience with firing After the box is made and put together curable at aiw cost, I think that this article a cannon by fuses, lighting paper, and sev- give it about 5 coats of shellac to make it will prove of interest to all who have eral other methods used, and getting a taste damp-proof. Shellac both inside and out- wanted a Geissler tube. Below are full of powder at one time, I decided to make side. Before fastening the spark coil in the box be sure the coil is adjusted to its best secondary output when connected to the batteries which are to be used.

Up to about 75 yards this will fire a cannon with one side of the secondary WAX grounded and the other secondary wire run through the air. This wire is supported by insulated wood sticks stuck into the grounds. Have the cannon grounded and the end of the wire about y% from the one side of the fuse hole with powder around it. Then if everything is arranged as described, when the button is presst the powder will go up in smoke. For firing a cannon more than 75 yards from appa- FIG.I ratus run one wire along on the ground /^o and the other through the air. Connect tlie ground wire to 'SPARK COIL the cannon. Fix the air wire as described before. This you will find is a very safe way to fire a cannon.

NEEDLE Code to Drawing : A, batteries ; B, spark

coil ; C, push button on top of cover ; D,

primary circuit ; E, secondary circuit ; F, secondary binding post on top of cover; WAX G, partition separating batteries; H, partition separating spark coil; K, spark coil FICE \ ibrator. In using this apparatus to fire a cannon with, make it a rule not to have the secondary leads over 20 to 30 feet long. These spark leads should be well insulated (at AIR SPACE least one of them) and the primary push button wires can be of any length desired up to 50 or 75 feet, but 20 feet is usually Details for Making a Home-IVIade Geissler Tube from an Incandescent Lamp and Appearance sufficient. of Completed Bulb When Excited from Even a Small Spark Coil. Some constructors make their cannon to accommodate a standard gasoline engine spark plug breech. directions for making such a tube from something which would be entirely safe at Others arrange an a burned-out lamp bulb, providing the and sane. insulated wire as shown in the accompany- vacuum is not destroyed. This" apparatus costs but little, to which piece of sealing Take a wax and soften is added the fact that it is safe. It is a it so that it can easily be prest into a good thing to be used at a camp when fir- shape somewhat like that in Fig. 1. Then ing a cannon for the raising and lowering hollow out tlie center as in Fig. 2. Stick of the flag, and is a safe way in which to a needle thru the wax and while still soft fire a cannon on July 4th. and hot press the wax firmly against the The apparatus can be placed as far as 75 side of the bulb as in Fig. 3. taking care yards away from the cannon. The things that the wax* is air-tight. Then connect needed would be 1 push button, 3 dry cells, one terminal of a 1 inch spark coil to 2 binding posts, a small ('4" spark) spark the needle in the wax and the other ter- coil, about 4 square feet of I/2 inch poplar minal to the base of the lamp. Turn on or pine, some shellac, screws and wire. I the current and the spark will puncture would recommend a section of a Ford coil the glass and the effect produced will be which can be bought for a reasonable that of a high grade Geissler tube. The amount. 25-7S feet/eac/i Pushbu/Zan^ purpose of the hollow space in the wax is as follows The inside measurement of the box should be 13'1." by 8^:;" by 3", the compartment This space is filled with air and when for the batteries A, A, A, being 8;4" by the spark punctures the glass, the air in bVi" by 3" separated by a partition, and then .—Z> this space rushes inside the bulb ; in this ] ^ a compartment 6':." by 3'/2" by 3" or any — way regulating the amount of air in it. suitable size for the spark coil which you Different colors are obtained with differ- have. The bottom and top should be made -3 ent air holes, that is, the larger the hollow about Vi" larger than the outside size of the space in the wax, the more air in the bulb. box for the sake of appearance. When I .T_L inserting the needle thru the When wax, putting the box together all joints should be take care that it just touches the glass of made by painting them with shellac and be- ® the light bulb. fore it dries screw it down tight so it will I have used this methcid of making be water-tight and damp-proof. When An Electric Igniter for the Toy Cannon Which Will Save Fingers, Geissler tubes for years and I have found connecting the batteries leave plenty of Mis-Fires and Premature Explosions. that it never fails to produce the desired wire for connections. The push button C, results ; as good as any tube I have bought. which is to complete the primary circuit to As the cost of each tube is very slight, and operate the coil, should be fastened on the ing sketch. This apparatus has been used every tube made produces a different color, cover above the compartment whicli has ver\- successfully by the Erie Y. M. C. A. I it very interesting have found to make nothing in it. and the Erie Boys' Club of Erie, Pa. a great number of them. The secondary binding posts "F" in the Contributed by Contributed by DAVID GOODMAN. diagram should be fastened on the cover GILBERT CROSSLEY. THE ELECTRICAL EXPERIMENTER July, 1917 mm

This cUpiirlintnt will award the following monthly piizis; First Prize, $3.00; Second Prize. $2.00; Third Prize, $1.00. The purpo.se of this department is to stiinulate 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 veiy elaboiate. and rough sketches are sufficient. AVe will'" make the•• mechanical drawings. Use only one side of sheet. Make sketches on separate sheets.

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 AN EFFICIENCY PLIER KINK. A GAGE THAT INDICATES RELA- A SUBSTITUTE FOR SWITCH Nature i)ruvi(lfs tor average conditions TIVE MAGNETIC ATTRACTION CONTACT POINTS. only and she supplied us with a reasonablx' OF METALS. When in need of switch contact points, thick skin where it is called upon to do The experimenter may often want to test old used .32 or .25 caliber cartridges come extraordinary amount of work or wear, but the effect of different metals under mag- in handy. The "Kadio-bug" with a lean one of the spots neglected by bountiful pocketbook can construct these at practi- nature is on the back of the index linger, cally no cost. between the first and second joints of the First clean the inside of the cartridge right hand. This is the spot that is charged shell from all dirt, by using a small pen- with the duty of opening "diagonals," knife fir half-round file. Xext take a com- "long-nose," "goosc-bill" and the commOn, mon brass wood screw that will fit inside ordinary, everyday i)liers, and on this spot the cartridge and place it inside one which more blisters can be raised to the square has been cleaned. Xow pour solder in and inch than on any other spot on our an- you then have a serviceable contact point atomy. It is perhaps better to put a drop of zinc The photograph clearly shows how to With This Simple Home-Made Testing De- chlorid on the inside of the cartridge to vice the Amateur Can Interesting "save your skin" and while it will save Make the solder stick better. Investigations of the Relative Magnetic make more time than skin, it is our skin that Attraction of Various Metals. Both Ferric if .screws are used which will come thru we are most considerate of. and Non-Ferric. on the rear of the base, wires may easily The spring that holds the legs apart be soldered to them. netic influence and an instrument, con- should be made of spring brass, phosphor Contributed by G. GRAXT WAITE. structed by the writer, to determine this particular effect is shown in the accompanying illustration. The action of the apparatus as shown in the photo is very- evident. As soon as a current is past thru the electro-magnet, the metal strip to be tested is either attracted or left neutral. In some metals as iron or steel, the armature or testing strip, will be moved consid- erably, but other metals like copper, lead, zinc are not affected at all. The effect of the magnet upon these latter metals can, however, be easily detected by so constructing the indicator that it will register tbt- least perceptible movement of the armature. Cartridge Shells, Boys. They It is quite evident that the slightest move- Save Your Make Good Switch Points, if a Wood or ment of the rod will move the pointer Machine Screw Is Firmly Embedded in the over a considerable distance. By passing Shell by Means of Solder. The Leads May Be Soldered to the End of the Screw. AC thru the magnet coil the relative magnetic repulsion of metals may be tested. Your STATIC ELECTRICAL Do You Want to Save Your Skin and The indicator arrangement may be con- A PECULIAR Temper? Then Simply Fit Your Pliers with PHENOMENON. a Steel or Bronze Spring Like That Shown structed from an old steam gage or clock and Your Worries Will Be Over. works. The pivot block can be obtained I am a stenographer, emiiloyed in an from an old bell. Care must be used in architect's office, and my duty is to write bronze or German silver and it is soldered making the instrument so that there is very- specifications, ten copies at a writing. In to one leg. or if soldering offers any dif- little iriction in the pivot rod support writing, a static charge is generated on ticulty the spring may be riveted to the leg. or in pinion and gear of the indicator. each of the carbon papers, which is sep- This kink is particularly useful in tele- Contributed by MARK SLABODNIK. arated from the next by the white paper. phone exchanges in trimming terminal racks On separating the carbons from the white or cable and rchiy work, where it is neces- placed at the bottom to keep the battery papers, which is done by pulling the ends the hour carbons, which protrude beyond the sary to cut and trim wires by from falling out. The contact is made as of the \\ the hite and which i]i)cration wears off considerable shown in the diagram, by means of the w bite papers, ith one hand and w "bark." The kink also allows the use of brass spring. papers themselves with the other hand, all lingers for pressure on the legs. Contributed bv ED.MUXD AX'GLIX. some of the charges are neutralized on

Contributed bv separation ; sharp crackling being indicative FRED'K SCHLIXK. CorA p/ug of this. I usually place all of the carbons J. ejftergt Lamp'^' r onto the machine, after which I draw quite A "BAMBOO" FLASHLIGHT NOV- a long spark from any part of tlie ma- ELTY. chine into my knuckle. A distinct and useful novelty in electric At first I received the shock unexpectedly flashlights is here shown ami described. To after bringing my hand near the charged I habit of plac- make it. first secure a battery for a tubular machine, as had formed a flashlight. .\ piece of bamboo with an ing the carbons onto the machine after inside diameter the same or nearly the ^—ref/ecfor each writing. After investigating the mat- hiifi burIon mysterious "what-is- same as that of the battery is then obtained. ter, I found that the in the machine. The length of the bamboo is slightly great- it" was developed A Distinct Novelty in Flashlights— It's Made Contributed by WM. LESKY. er, say an inch and a half, than the battery. of Bamboo and Will Make a Very Attractive The bamboo must have a joint about a half Gift or Favor for Parties and Dinners. of screen wire. inch from one end. A hole is bored thru with a small piece common the center, just large enough to permit the AN EMERGENCY FUSE PLUG. A single strand of wire will pass about

: and flashlight bulb to fit tightly. .\ i)iece of Here is ;i little idea of my own on an 3 amperes 3 strands 6 amperes, 6 bright tin, shaped right, is placed around "Emergency Fuse." Take an ordinary at- strands about 10 amperes. the bulb to act as a reflector. .'\ cork is tachment plug and connect the terminals Contributed by HUBERT YEAGER. !

200 THE ELECTRICAL EXPERIMENTER July. 1917 Where the Radio Amateur Fits in the U. S. Naval Reserve By -M. B. WEST, R.\DIO GLTvNER, U. S. N. R. F.

amateur has at last an oppor- the direction of an officer of the naval should be particularly attractive to stu- effort will be made by dents and others, as it gives an opportunity THEtunity to be of real service to the reserve, and every Government, and one that will not them to assist amateurs in solving the many for training and also saving during vaca- connection tion period. in any way interfere with his puzzling problems that arise in feature is especially liberal is career in civil life. The argument with their stations. One that the re- that member of the reserves will be dis- that the amateur would be of inestimable It is not necessary to enroll in a it is earnestly charged at any time during peace at his benefit in time of war has so often been serves, to join in the drill, but that all will do so. So far this own request. Active service is not com- made that it has at last been recognized. hoped feature has been worked out more com- pulsory, and orders to active duty are only Yet it is clear to anyone who gives it a moment's thought, that without at least pletely in the Middle West in connection issued at the request of members them- some preliminary training most amateurs with XAJ, the naval station at Great Lakes, selves, and will be arranged so as to interfere as little as possible with your regular would fail miserably if suddenly placed in Illinois. charge of a large radio station. The Class 4, Xaval Reserve, is a very business. The only time the reserves can be organization, and creates an oppor- called for active duty, is in time of war, It is with the intention of remedying liberal especially adapted to and it is intended to use them at the less this situation, that the Class 4, Xaval Re- tunity that seems enroll, must be important land stations so as to relieve the serve, has been created. In as far as amateur needs. To you citizen, be able to send and regular officers and men for their active possible, it is hoped that amateurs enroll- an American words per rnin- war duties. Information in detail can be ing in the reserve will at once ask for a receive at the rate of ten usual physical secured from the nearest naval recruiting short period of active duty so as to be- ute, and be able to pass the will officer, who will be glad to give you any come familiar with the requirements of examination. On enrollment members of until information you may require. the radio work of the navy. Then they receive a yearly retainer fee $12.00, have perfected thern- Here is an opportunity to prepare your- will return home, and it is hoped will join such time as they to handle their self so as to he of real assistance to the one of the drill routes that have_ been or- selves sufficiently to be able par with regular Government, and at the same time be well ganized in connection with the Xaval Sta- work in a manner on a such time they will paid while doing so. tions. The purpose of these drill routes naval practise. After receive an annual retainer pay equal to As it is the first appeal to the amateur, is to perfect these amateurs in handling corresponding if are to live up to the reputation that radio business according to the rules of two months' pay of their we In addition has been made for us we should respond the navy. grade in the regular navy- traveling expenses to and from gladly and willingly. We can assure you And think what a difference it vvould they receive uniforms, meals and that you will be pleased with the treatment make in amateur working conditions if all place of training— while on active duty and will amateur business was handled in an orderly lodging and the regular pay from the time you receive until they return return home w ith a much more friendly feel- and thorolv efficient m.anner they leave their homes all clear money, and ing towards "Uncle Sam" and his navy. These drill routes will be placed under to them. This is

AN EXTREMELY LIGHT-WEIGHT a high pitch, musical tone and with the aid it does not interfere with any of the other RADIO TRANSMITTER of this vibrator this is readily accomplished, inclosed instruments. Taps are led off at AND RECEIVER. which was heretofore impossible, due to four different positions, and are terminated in four plug The illustrations herewith show one of forced action of receptacles which the latest types of portable light-weight, the spring con- are placed at the radio transmitter and receiver, adaptable stituting the com- left of the panel. for both military and civilian duty. mon form of vi- A flush type hot This outfit was designed and built by Mr. brator. wire ammeter is also A. B. Cole, a prom- secured to the inent radio engineer B a k e 1 i t e control of Xew York Cir\\ panel. The antenna transmitter is The change-over switch stationed in the main is shown in the compartment while background and the the receiving outfit transmitter key at is placed in the cover the right. of the case, which is The receiving ap- a substantially built paratus is mounted fiber affair measur- on a separate 10 X 10 X 12 ing Bakelite panel and inches. It is equipt contained in the case •with heavy carrjing as illustrated. This straps. The trans- receiver comprises mitting set com- an inductive coupler, prises the following: with a fixt secondary —A high tension and tuning is ac- spark coil placed complished by means within the case ami of a secondary vari- w h i c h is used to able capacity. This charge a condenser One of the Latest Compact latter controlled thru a special Radio Sets Designed Espe- is cially for Field Military Ser- by of a grad- quenched spark gap. means vice. It Has a Powerful uated handle noted This is seen on top Transmitter Operating on a at the upper right of the panel, indi- Storage or Dry Battery. hand corner. An en- cated by the hori- detector is employed with this zontal circular disc. closed mineral

set ; it is placed in the center of the cabinet. This gap is of the quenched type and The round instrument below the detector is a frequency buzzer used for testing pur- is composed of two high directly beneath the perfectly parallel poses, and the button buzzer is used to start the buzzer. The pkig plates. The to:> the left of the push button inter-connects electrode is connect- to telephones ith the set, while the plug to ed to the helix by the w interlinks the antenna and groimd a flexible conductor. the right sending apparatus. The switch to A special independ- thru the left of the sending key connects the an- ent vibrator is con- the sending or receiving nected with the primary of the induction The tuning inductance consists of a num- tenna with either the instruments: by turning to the left, the re- coil and this is located behind the forward ber of turns of wire placed on a frame, the instruments are connected, and to binding posts. It is an essential feature size of which is equivalent to that of the ceiving transmitting. that the frequency of the emitted w ave have inside of the dimensions of the box, so that the right is for ! ,

July. 1917 THE ELECTRICAL EXPERIMENTER 201 Amateur and Experimental Radio Research By RAYMOND FRANCIS YATES

TART I. member that the application of wireless is Knowledge Necessary for Research Work. all the prcscnt-day fields of sci- not necessarily limited to the transmission Contrary to the general opinion possest OFentific eiuk-avor, there is probably of intelligence. In the future this w ill con- by experimenters, it is next to impossible mine more promising or proNikola Tesla tells us that within 25 years we will be sending radio controlled boats to any port of Europe without a man on board We may put much faith in statements made by Tesla, as his accomplishments are many and great. If it is possible to control ves- If You Make Up Loading or Other Induc- sels via radio, why will it not become pos- Trouble tances, Take the to Either Measure sible to control airships, trains and auto- or Calculate the Inductance in Micro-Henrys The Radio Student and Investigator Should indeed superficial or Centimeters. It Always Pays. mobiles? It would be a Provide Himself With a Number of Variom- observer who would conclude that radio is eters of Different Sizes and Known Induc- field of radiocommunication. There seems anything but a fruitful field for those who tance Values. to be a lack of real, scientific enthusiasm desire to enter irrto penetrating and pro- physics of the expanding hot-wire meter. among the amateurs of the United States, ductive investigation. One should be familiar, however, with in- especially in regard to the perfection of the ductance, capacity, resonance, damping, art, and it is the object of the author to resistance, impedance, etc. One should try and offer a few suggestions with the know why a variable condenser will alter hope that these amateurs will regard their the wave length by changing th« capacity work in a more serious attitude with the of the circuit; why the inductance of a intention of developing something original. tuning transformer has the same efifect, I have talked to many experimenters who and why the quenched gap has a tendency thouglit that they had conceived a valuable to set up sustained oscillations. It is sur- idea, Init either they did not possess the prising how many suggestions present them- courage to develop it or they thought it selves when a working knowledge of the was beyond their ability. If dc Forest had v.'irious instruments is acquired. Ideas then had the same attitude, we would not have come fast and numerous. The moral here

! every article the Audion ; if Marconi had lacked luillinch- is— study Read and book ing inspiration and c(uirage, probably de you can get hold of. If you don't under- Forest would not ha\e needed to in\-<'nt stand it the first time, read it again. It his .\udion detector at all. Among the would probably take you several years to 4(10,000 and more radio experimenters in work out the law of H'.L. = 59.6 ^/ L X C the United States, there are undoubtedly but by reading the up-to-date magazines on many F'cssendens, Marconis and de F'orests, the subject and elementary books such as who either lack courage or enthusiasm, to the "Wireless Course" by Gernsback, Les- enter research work. carboura and Secor, you can learn just Possibilities of the Field. why, for a given wave length, that when The possibilities of development in wire- C is decreased, L must be increased, etc. A Good Type of Experimental Radio Trans- just None are so blind as those who won't see! less are limitless. WV have entered a mitter Which May be Used with a Phantom new era— the Wirclrss F.ra. We must re- or "Dummy" Antenna. (Conliiiucd on fiagi' 218) 202 THE ELECTRICAL EXPERIMENTER July, 1917

A PECULIAR EXPERIMENT WITH MILITARY SIGNAL LIGHT AND AN ELECTRIC BIRTHDAY CAKE A LAMP BULB. BUZZER. WITHOUT THE DOUGH. A curious experiment can be made with A very compact and serviceable arrange- The materials required for this stunt are a 110 volt. 16 candle power carbon lamp ment of military signal light and tell-tale a tin pan, about ten inches in diameter and Anyone who has seen the tip broken off buzzer is shown in the accompanying illus- four inches high, a number of miniature- an electric lamp while burning has noticed tration. It was developed by R. C. base colored lamps, and a source of current. After obtaining that it soon becomes brilliant, then goes out. these, proceed as fol- For this paradoxical lows : experiment, now break Mark off on the bot- the tip A off as small tom of the tin pan, as possible, but enough the desired positions of to let the air in, then fill the lamps, and punch up to B with gasoline. holes. H, at these Connect the lamp in points. The holes must circuit to 110 volts, and be of such size that the the lamp w ill- burn screw base. C, of the will fit in about Yz candle power. lamps, L, just Xow, tho this is only them. This done, turn a 110 volt lamp and or- the pan over and solder dinarily in perfect con- the Xo. 20 wires, M, to Scout S ignal Corps Division^"Will Find This Combined Buzzer and Signal dition, it would burn The Boy all the center connec- and Serviceable. Be Sure You Have a Good Lens to Start Light Outfit Very Light tions of the lamps, out in a very short With, and a Parabolic, Well Polished Reflector. and time on a 220 volt cir- continue this wire to it is said him to be particu- the source of current, which may be a cuit ; connect it to a 220 volt circuit, and Avery, and by will apparently burn at the same candle larly efficacious for 'flashing liglit signals flashlight battery or two, B, placed under power or Yz. When the lamp has burned at night; the, tell-tale buzzer sounding for the pan. If the source of current is a for about three minutes on either voltage, each dot and dash as th^y are sent out by storage battery or a step-down transformer, place a match at the opening and a small the transmitting key or switch on the side the wires going to the same should be con- and vers- white light will burn like a candle. of the battery case. cealed,. The hardest part of the work is This idea should prove very useful to now finished. the signal corps division of the Boy Scouts. The icing is now to be put on the "cake" The present signaling device was found and in order to make it stick, paper should very efficacious compared to the acetylene be pasted on the pan. The icing is spread lantern previously used in the United States Army signaling work, the electric lantern here illustrated having signaled over a distance of 5 miles at night and 2 miles in daylight. The instrument as developed by its inventor measures 10;< inches in length by 2]i inches extreme diameter. The transmitting key folds over so that when carried in the pocket it cannot accidentally close the circuit. HOLY SMOKE! ANOTHER ELECTRIC ALARM CLOCK. The illustration shows an electrically operated alarm clock of new design. One terminal of the battery is connected to a metal standard, holding a brass pulley, on copper which is wound a few turns of tine For Birthday Parties an Electric Cake Is or brass wire. One end of the wire is fast- Always Welcome. This One Is Made from Battery Is Placed a piece of cord, the other end of a Tin Pan Iced Over. The ened to Within the Pan. which is tied to the alarm winding key. second terminal of the battery is con- The smoothly over the paper up to and touching nected thru a bell to one foot of the alarm the lights. When hardened, this novelty clock. will have all the appearances of a genuine A Novel Experiment with an Incandescent operation is as follows: The mode of iced cake with lights mounted in the top. Lamp Which Is Filled Up to "B" with Gaso- circuit is open at the cord due to its line. When Connected to Live Circuit Gas The Contributed by VICTOR DE FLORIX. Is Generated and May Be Ignited at A by non-conductivity. When the alarm rings, a Match. until the wire is it winds the cord on it clock and the standard should be securely drawn on to the key. This completes the becoming stronger as long as the gasoline fastened to a suitable baseboard. circuit and operates the bell or any other lasts, same depending on the size of the Contributed by A. H. BETLER. device. The magnet wire is of course long tip, bul as soon as you open the switch, TO TRANSFER PICTURES TO the light and flame go out. WOOD. Place the lamp in a horizontal position

salt in soft : float your and the lamp acts the same as tho you had Check sfinng Dissolve water broken the tip while it was burning. It photo print on the surface, picture-side up; will only behave in this paradoxical manner norm let it remain about an hour. The wood cloa' while vertical, tip up and base down. should lie of bird's-eye maple, or other light-colored hardwood. Varnish with the . Contributed by GEORGE C. MACLEAN. licst copal or transfer varnish.

Take tlie picture from the water : dry a FORMULA FOR WOOD'S METAL. little lietween linen rags: then put the en- graving, picture side down, on the varn- This silvery fine-grained alloy fuses be- ished wood, and smooth it nicely. If the tween I.tI and 162 deg. Fab., and is adapted picture entirely covers the wood after the to soldering, and mounting crystals as margin is cut off, so that no varnish is galena, silicon, etc., for wireless work. exposed, lay over it a thin board and heavy Tin 2 parts weight : leave it thus over night. If you Lead 4 parts wish but a small picture in the center of Bismuth S to 8 parts What! Ding-bust-it. if Here Ain't Another apply the varnish only to a space Contributed by "Electric" Alarm Clocl<. The Inventor Ar- the wood, ranges a String and Wire So That When the size of tlic picture. Dip your forefinger \V. Ai.BERT WTLSDOX. the Is Finally Clock Key Turns, Wire in salt and water, and commence ridiliing Grounded, Closing the Bell Circuit. to the Due to the advent of the war, we are off the paper : the nearer you come particularly desirous of obtaining manu- enough so that when the alarm key has picture, the more careful you must be, as scripts describing original and practical turned its full rotation there is still some a hole would spoil your work. " " Electrical Experiments. wire wound around tlie pulley. Both the Contributed by V. C. McILVAINE. I :

203 July, 1917 THE ELECTRICAL EXPERIMENTER Experimental Chemistry

By .VLBI-RT W . \VlL.SI>ON Fourteenth Lesson HYDROCHLORIC ACID. in such a ratio that its composition may be thus obtained, which is sometimes some- represented by the formida, HCl. what colored, is the Hydrochloric or ^turi- ASIL \ALr:.\'n.\i; in tUc 15tli burns in chlorin, the only atic acid of commerce. The discoloration Century first described the prepara- 1. Hydrogen being Hydrochloric acid gas. is due to the presence of impurities, such tion by a process similar to the product [Hydrochloric as Iron and organic substances. in use. He called it 2. When hydrogen chlorid B one now Hydrochloric acid forms a part of the electric cur- "Spirit of Salt." That which cs- acid] is decomposed by an and chlorin digestive fluids of the stomach. The acid capcd from anything easily in intangible rent, equal volumes of hydrogen is supposed to be secreted in what is known called "Spirit." Thus Sl>irit are evolved. form was a as the Border Cells, whose exact func- 3. When a mixture - of equal volumes of Ttiist/e fube Safe/y fu6e hydrogen and chlorin r/7/j//e fuOe is exposed to the direct sunlight, or to the Small ring action of an electric fsupporf spark, the gases com- fii/dber bine w i t h explosive Cannec/ar violence, and Hydro- \ RuMer chloric acid gas is formed with no resi- co/7nec/or\ due. Furthermore, the volume of the result- Large rmg ing gas equals the ^sappor/ sum of the volume; of hydrogen and chlorin used. 4. When a given volume of dry hydrochloric acid gas is treated with sodium amalgam, the chlorin is withdrawn by the sodium in the amalgam, and a vohmie of hydrogen remains which is half the original volume.

5. No derivative of rig69 Hydrochloric acid is Method of Collecting Hydrochloric Gas By known which contains the Downward Displacement in a Dry Test Experimental Apparatus Set Up for the Preparation of Hydrochloric Experiment 79. less hydrogen or less Tube. See Acid In the Laboratory. chlorin in a. molecule. tions are still unknown. The gastric juices etc., are indica- 6. weight in which hydrogen 11/ Wine, Spirit of Wood, The ratio by of the stomach in normal condition con- long is 1 to 33.45. Hence, tion of the crude theory of spirits so and chlorin combine tain about 0.33 per cent of free acid. gas of Hydro- in vogue. Hydrochloric acid being a_ the lowest molecular weight Aside from the aid which Hydrochloric salt when it is chloric acid is 36.45, a number which has which is liberated from acid gives in peptic digestion, its presence treated Sulfuric acid, it naturally been verified by several different methods. with was is important, in that it destroys the germs regarded as a Spirit of Salt. Occurrence : of fermentation and disease, and probably the 17th free Acid Glauber prepared this gas in The occurrence of Hydrochloric dissolves some mineral salts. Its action is its affinities are too Century by treating Sodium Chlorid [Com- in Nature rare, as in destroying germs permits the food to be sulfuric acid. exhalations of mon salt, Na CI) with strong. It occurs from the stored in the stomach for some time with- I'riestly, in l/'72, first obtained it in pure active volcanoes, as \'esuvius and the out undergoing decay. condition. He called it "^larine Acid Air." fumaroles of Hecla. It is also a constitu- Prrparation" ; Lavoisier, rivers Upon the theory introduced by ent of some streams and which The method generally used in the labora- necessarily contain oxygen, their origin in volcanic mountains. that all acids have tory is to treat common salt, Sodium Hydrochloric acid was for a long time be- It is found in the waters of certain South Chlorid [NaCl] with Sulfuric acid. The lieved to contain oxygen. American rivers that have their source in reactions which may take place are About 1810, Davy established the ele- the volcanic districts of the Andes. [I] KaCl H,SO. HCI NaHSO. hence the salts, derived + = -f mentary nature of Chlorin, and The series of from Hy- .^odium Sulfuric Hydrochloric H\-drogeti true nature of its hydrogen compound. Hy- drochloric acid, are widely distributed and Chlo Acid Acid S^oHium drogen Chlorid [Hydrochloric acid[. The of great importance. In general, they are Sulfate correctness of his results became generally crystalline, stable, and soluble [except Sil- 121 2XaCI -F H,SO, 2HCI NajSO, Sodium Sulfuric Hydro- Sodium facts lead ver], are decomposed by water, recognized shortly after. Many tho some Chlorid Acid chloric Sulfate to the conclusion that Hydrochloric acid especially if evaporated with it. Common Aci.i gas is composed of Hydrogen and Chloritt salt. Sodium Chlorid [NaCl| is the most If an excess of acid is employed, ar _ important of the chlorids, and in fact is Ih/ille fube^ the parent substance from which almost all chlorin and its compounds are made, >\ r, as well as all of the sodium compounds. In the manufacture of Sodium Car- bonat by the process in most common u:c, .Salt is first treated with Sulfuric acid, by which it is converted into Sodium Sul- fate. In this stage of the process. Hydro- chloric acid is necessarily formed in large Atsi'hcd if ajtting cjuantity. Formerly this was allowed to Fn. rubber ccnmctor escape into the air, but the injurious ef- ^'973 Q fects which it had upon vegetation, caused laws to be enacted whereby the manufacturers were compelled to prevent the Shape of Glass Tubes Used to Connect Up the Apparatus Here Illustrated and Method escape of this gas. The waste gases are of Cutting Rubber Sleeves Diagonally to now caused to pass thru towers filled with Make Them Slip On Tubes Easier. Fig. 70 Fig. 7 bricks so arranged as to present a maxi- the first reaction, a moderate heat is re- mum of surface, over which water is kept At Left— A Wolff Bottle With Three Neck"-: quired, and a readily soluble salt. Hydrogen At Right— Erlenmeyer Flark Which May Bo constantly passing. The gas dissolves in Substituted for the Florence Flask Specified. the water qtn'te readily, and the solution (^Coiilinucd I'll paih' 220) . ; ;

1917 204 THE ELECTRICAL EXPERIMENTER July.

either shrinks or swells by dryness or 1 per cent to 50 per cent, based on the weight of one gallon of water at 40° F. moisture, is capable of being formed into woods of most = 8.33888 lbs. [avoirdupois], or one tluid an hygrometer, such as Wminklesl etc. ounce of water weighing 456.03 grains kinds! particui-.rly ash. deal, poplar, [avoirdupois]. The following is the most lasting and convenient mode of construction for an in- For each fluid ounce of water take strument of this description. Take a very fine balance, and place in For a 1 per cent solution. . 4.66 grains " • it a sponge, or other body which easily 2 .. 9.38 • " " absorbs moisture, and let it be in equilib- 3 .. 14.10 •' •' " rium with a weight hung at the other end 4 . 19.00 •' " '• 5 .. 24.00 " " 6 "' .. 29.10 " " " 7 .. 34.30 •' " ' 8 .. 39.60 " ^ " " 9 .. 45.09 " " " EDITED BY S.GERNSBACK 10 .. 50.67 ^^y^ertfaomp " " " Under this heading we will publish every 15 .. 80.48 useful information in Mechanics. " " " izj^^ffcfher month 20 .. 114.00 Electricity and Chemistry. We shall be • " " pleased, of course, to have our readers send 25 .. 152.00 •• " • us any recipes, formulas, wrinkles, new 30 .. 195.44 • " 1 r^ the experimenter which " ideas, etc.. useful to 35 • 245.56 will be duly paid for. upon publication, if " " " 40 .. 304.02 acceptable^ " " ' .. 373.10 ^ 45 " " " .. 456.03 HOW TO MAKE A CHEMICAL 50 BALANCE. It should be noted that the above table The accompanying photo ilhistrates a applies to water, percentage solutions for chemical balance constructed by the writer other liquids would necessarily have to be While not being extremely accurate it figured on the weight of the particular ® nevertheless will measure quantities to the liquid. A Simple Hygrometer Which Can Be Made degree of accuracy generally demanded in Percentage solutions are also, sometimes, at a Cost of a Few Cents, from a Sponge, a Paper Scale and a Lightly Pivoted Lever. an amateur's shop or laboratory. It is not made up from a saturated base. This difficult to construct and ordinary care be- method is incorrect unless it is so desig- of the beam. If the air becomes moist, ing used, it can be made to weigh within a nated in giving the formula, that is. by the sponge, becoming heavier, will prepon- gram. stating in the formula saturated solution derate ; if dry. the sponge will be raised The illustration is self-explanatory, but base. Such percentages are made by plac- up. This balance may be contrived in two words may not be amiss. To make liquid used more of the chem- a few ing in the the that ways, by either having the pin in mid- it, first obtain a telephone ringer set as ical than the liquid will carry in solution dle of the beam, with a slender tongue, shown in figure. It is not necessary to pur- this resulting solution is liltered to re- a foot and a half long, pointing to the di- chase a brand new one, hut go to some move the excess chemical and then used visions of an arched plate, fitted on it, or electric or telephone repair shop where you as base. For example, to make a 10 a the other extremity of the beam may be may secure a ringer for less than fifty per cent solution, 10 per cent of the base so long, as to describe a large arc on a cents or even for nothing, possibly. Pro- is used and 90 per cent of the pure liquid, board placed for the purpose. ceed to rearrange the different pieces so as or in other words. 1 ounce of the saturated To prepare the sponge, it may be neces- to appear, after adding other parts, like solution to 9 ounces of the liquid. sary to wash it in water and. when dry. in that shown below. On the armature, Contributed by ALBERT W. WILSDON. water or vinegar, in which sal ammoniac solder or bolt a strip of metal, preferably or salt of tartar has been dissolved and aluminum, Y2" x 7" and on the ends of this let it dry again: then it is fit for use. The "beam" attach two circular 4" pans. Be- TO PETRIFY WOOD. instrument can be hung against the wall^; low one of the pans place a right angle Equal quantities of gem salt, rock alum, and. in that case a bit of steel, as at "A," strip and adjusting screw, in order to be white vinegar, chalk and Peebles' powder. should be placed before the needle, to keep able to make pans balance. Back of the This solution will petrify wood or any other straight. instrument, after fixing on base, place a porous substances if put in after the ebul- it Contributed by WILL M. DUFFIE. strip for an indicator. lition is over.

A Stone Coating for Wood : Forty parts chalk, fifty of resin, four of linseed oil, COLD SOFT SOLDER.

melted together ; to this should be added Everyone at sometime or other has had part of oxid of copper and then one one occasion to solder two pieces of metal, This last should be part of sulfuric acid. which because of their composition, or be- Apply with a brush added very carefully. cause of attached parts, could not be raised while hot. to the temperature that even soft solder Imitate Dark Woods ; The appearance To flows at. The following solder meets that of walnut may be given to white woods demand, as it can be used without heat. painting or sponging with a concen- by Precipitate some copper from a copper solution of permanganat of trated warm solution, such as copper sulfate or copper potassium. The effect varies for differ- nitrat by means of zinc or iron filings. ent kinds of woods, some becoming stained Into a mortar pour some mercury and the rapidly, others requiring more time. When copper precipitate. Add a few drops of stained wash thoroly with soft water. After dilute sulfuric acid and grind until the cop- the has dried it may be varnished, wood per has united with tlie mercury. Wash will be found to very closely resemble and the amalgam with water till bright and the natural dark woods. clean. Put into a cloth to dry and by means

Polish : Only a very few ex- To Wood of a twisting motion, like grapes are their own cabinets perimenters who make strained, squeeze out the excess of mercury polish on their know how to put a good copper amalgam is just workable Every Experimenter Needs a Small Balance until the woodwork. The following is a very good for Weighing Chemicals On. Here's One by the fingers. Rub well into the surfaces a piece of pumice stone and Made from a Telephone Ringer Frame Fitted method. Take to be joined, and press together over night. of Pans and a Scale. over the work with a Set water, and pass regularly Some of the mercury penetrates the sur- until the rising of the grain is cut dowii the copper crystallizes Finished with shellac, this instrument faces, and some of then take tripoli and boiled linseed oil, becomes very hard. will make a neat looking and useful little out. and the compound and polish to a bright surface. compound is silver piece of apparatus for cliemical or photo- Strange to say. this Contributed by V. C. McILVAINE. mercury, a pliable graphic work. white. By using more hardens slowly. If Contributed by MARK SLABODNIK. metal is obtained that up with more HOW TO MAKE A HYGROMETER. the solder is too hard, grind mercurv. Keep gold and silver jewelry, "PER CENT" SOLUTIONS. The hygrometer is an instrument to etc., out of the way. as mercury destroys A table giving the weight in grains measure the degrees of dryness or mois- them. [avoirdupois] of any chemical substance ture of the atmosphere. There are various _ Contributed by H. V. PFEIFFER. required to make a per cent solution from kinds of hygrometers; for whatever body —

July, 1917 THE ELECTRICAL EXPERIMENTER 205

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

15.00 Cash in Prizes. Get Busy, Boys!!! Here is—your chance to win a cash prize for a few minutes' brain work. The big question now confronting every radio amateur is "What can I do with my wireless apparatus?" To help the more than 400,000 loyal radio students and en- ihiisiasts to apply their kuowlcdu'c and, most important of all, to utilize their instruments for some practical electrical or communication purpose other than wireless, we shall pay two prizes—one of $10.00 and one of $5.00 respectively, for the best suKnestion as to "what to do with your radio set during the war." Be brief; 100 to 200 words should tell your story, keinember— it's the "idea" that counts. Get busy at once, ijoys, as we want all suggestions in by July 25th, at the latest, so that the results can be announced in the September number of The Electrical Expf.ri.m enter. And don't forget we must have thoroly "practical" ideas. Address the Editor, Radio Problem Contest.

A GROUP OF REPRESENTATIVE AMERICAN AMATEUR RADIO STATIONS. $3.00 Prize This Month Awarded to Amateur Radio Station of 8— Parker Wiggin. Kansas City. Kan. 1— William P. Aldrlch, Westfield, 2 Mass.; Radio station of Orney Dunnum. Hannaford, N. D.; 3— N. W. Lockwood. East Orange. N. J.; 4— Lucas Tylekens. Jr.. Kansas City. Mo.; 5—Walter Reimer. Milwaukee. Wis.; 6— Lester S. Fawcett, Independence, Iowa: 7—Ole B. Ritchey. Lake City. Mich.: 9— Lovell H. Cook. Mexico. N. Y.; 10— Henry W. Hall, Beeville. Tex.; 11—Otto Vandell. Brooklyn. N. Y.; 12— Hubert F. Jordan, Evanston, III.; 13— Palmer Reist, Dayton, O. — —

206 THE ELECTRICAL EXPERIMENTER July, 1917 Some More Representative American Amateur Radio Stations.

14— Radio Station of Louis Falconi. Fort Stanton. N. Mex.: 15— Lessesne R. Allison, Statesvllle, N. C: 16 Frank O. Walsh, Jr., Augusta, Ga.: 17—Geo. Anderson, Dorchester, Mass.; 18—James B. Armstrong. Ithaca. N. Y.; 19— L. C. Herndon. Portsmouth, Va.; 20—Allen B. Du Mont, Montclair, N. J.; 21— IVIorris Pollack, Chicago, III.; 22— H. Muysklns, Jr., Lynden, Wash : 23—Geo. M. Bends. Utica, N. Y.; 24— Earl McClure, Van Wert, O.; 25 Butswick Brattland, Ada, Minn.; 26—Geo. E. Meldrum, Jr., Carrollton. III.: 27 Clyde R. Battin, Athens, Ohio. —

July. 1917 THE ELECTRICAL EXPERIMENTER 207

THE MARVELS OF RADIO- NIKOLA TESLA RECEIVES THE of the Institute to a resident of the United

ACTIVITY. "EDISON MEDAL." . States of .America and its dependencies, or of the Dominion of Canada, "for meri- (Continued from page 171) Nikola Tesla, the famous electrical torious achievement in electrical science or wizard, who was awarded the seventh Edi- of the leaves being indicative of the amount electrical engineering or the electrical arts." medal on December 13, 1916, "for of Radium in a certain amount of sample. son Kulhcrford showed that the discharpinK meritorious achievements in his early orig- B. A. Behrend said: of ions inal work in polyphase and high-frequency eflfect is due to the production "By an extraordinary coincidence, it is electric currents," received the medal at a or ilnm/ed particles of the gas thru which exactly twenty -nine years ago, to the very presentation made at the annual meeting the radiations pass. In an electric field, day and hour, that there stood before this of the American Institute of Electrical En- positive ions travel to the negative electrode Institute .\ikola Tesla, and he read a de- the discharge gineers, on May 18. and vice versa ; thus causing scription of his great discovery of the gen- of an electrified body. If a sufficiently The Edison Medal was established upon eration and utilization of polyphase alter- strong field is used, the ions are all swept the initiative of a group of friends and nating currents. He left nothing to be to the electrodes without appreciable loss. associates of Thomas .'\. Edison, for the done for those who followed him. His The rate of discharge then reaches a ma,\i- purpose of recounting and celebrating the paper contained the skeleton even of the muni, which is not altered by an increased achievements of a quarter of a century in mathematical theory. voltage, this maximum current being called the art of electric lighting, with which the "Three years later, in 1891, there was the saturation current. The ions produced name of Edison is imperishably identified. given the first great demonstration, by are in every way identical with those pro- It was decided that the most effective Swiss engineers, of the transmission of duced by X-rays. This phcnomcncm of means of accomplishing this object would power at 30,000 volts from Lauffen to ionication is the basis for the conductivity be by the establishment of a gold medal, Frankfort by means of Mr. Tesla's sys- of gases caused by radioactive substances. which should, during the centuries to come, tem. years later this was followed serve as an honorable incentive to scien- A few Radium by the development of the Cataract Con- tists, engineers and artisans to maintain struction Company, under the presidency of Radium has been definitely determined by their works a high standard of accom- our member. Edward D. Adams, and with as an element, atomic weight 226.2 (Mme. plishment. color the aid of the engineers of the Westing- Curie). Jt imparts a brilliant red The Edison Medal was. therefore, es- house Company. It is interesting to re- to a flame and red predominates in its tablished and endowed with a trust fund, production of Radium call, here to-night that in Lord Kelvin's flame spectrum. The under an indenture dated February 11, largely from the ore report to Mr. .Adams, Lord Kelvin recom- is in this country 1904, whereby the American Institute of in mended the use of direct current for the carnotite, an Uranium oxid, found Electrical Engineers agreed to award the Radium is ex- Colorado and Utah. The medal annually. It is awarded each year the ore to- tracted by chemical means from by a committee consisting of 24 members gether with Barium, from which it is separated by fractional crystallization. The series of changes, there being bromid salt of Radium is slightly less sol- dergoes a final product uble than that of Barium, so on cooling considerable evidence that the is more active a solution, crystals richer in Radium than is lead. Polonium much Radium, but occurs in smaller quan- in Barium separate out first. .-Xfter six or than milligrams eight successive operations, pure crystals tities. Marckwald obtained three of Radium bromid are obtained, which are from fifteen tons of pitchblende residue. then ready for the market. The amount of Polonium in a Radium mineral is 1/5000 of the amount of the The prominence attained by Radium is Radium. due more to its ease of production and the Another body, known as "Ionium," has amount of easily secured ore than to any been recently separated with similar radio- exceptional properties it possesses over active properties. Ionium compounds are many of the other radioactive elements. several thousand times as active as those Besides the rrfdiations given off by Ra- of Uranium. The especial interest in dium, there is produced in addition a gas, Ionium is that its decomposition product known as "emanation." This gas is about is Radium, altho its period of transforma- a lunidred thousand times as active as tion is much longer than that of Radium. introduced into a Radium itself. When It has been found that Uranium, Ionium, it causes a bright glow. This glass tube Radium, Actinium, Thorium— all break Nikola Tesla. Prince of Electrical Inventors. illumination "Edison glow increases to a brilliant down, some giving off emanation, into new Who Was Recently Awarded the as zinc Medal." when substances which phosphoresce, substances which in turn break down again sullid. are put into a tube containing into others, and so on thru the series. development of power at Niagara Falls emanation. Fig. 2. Tliis phenomenon is nothing more or less and for its transmission to Buffalo. than a spontaneous commutation of mat- By means of this emanation a finer esti- "The basis for the theory of the oper- ter. mation of amounts of Radium than by the ating characteristics of Mr. Tesla's rotat- ordinary electroscopic method can be made. Perhaps the ancient Alchemists' ideas ing-field induction motor, so necessary to off and The emanation is driven by boiling were not entirely wrong! its practical development, was laid by the conducted into a suitable electroscope and (To Be Continued) brilliant French savant Prof. -Andre Blon- noted the rate of collapsing of the leaves del, and by Professor Kapp of Birming- standard. Quantities as compared to a ham. It fell to my lot to complete their of radium as small as .000,000,000,001 gram ELECTRIC RESISTANCE OF work and to co-ordinate—by means of the This can be detected and determined. SELENIUM CELLS. simple 'circle diagram'—the somewhat mys- emanation method is used to determine the terious and complex experimental phenom- According to Professor H. Greinacher amount of Radium in rocks and minerals. ena. As this was done twenty-one years of Zurich, selenium cells of the original ago, it is particularly pleasing to me, upon .Another method for quantitative measure- Shatford Bidwell type, which he studied the coming of age of this now universally ments of small amounts of Radium, when together with Mr. C. W. Miller, behave accepted theory—tried out by application not less than 1/100 of a milligram is pres- with respect to alternating currents as they to several million horse-power of machines ent, is to place the tube containing the behave when exposed to light, and show operating in our great industries—to pay Radium some distance from a lead screen polarity when traversed by continuous cur- an my tribute to the inventor of the motor and measure the rate of discharge of rents. Commiuiicating his observations to rate and the system which have made possible electroscope, as compared with the the German Physical Society, Greinacher of the electric transmission of energy. His caused by a standard amount radium stated that the resistance of the selenium name marks an epoch in the advance of similarly placed. The material being in- rose when direct current flow-ed in the cell electrical science. From that work has vestigated must be at least a month old, resistance dark, that this increase in was electrical art." be in enuil- sprung a revolution in the in order that the emanation different for positive and for negative cur- to decay ibrium with the Radium (due rents and increased with the time, and that and recovery, explained later). This as selenium cells acted in a certain sense like gests that Greinacher's cells had been of is simple direct, as the tube method and current rectifiers. These statements are peculiar kind. That selenium cells are very the material need not be opened nor (|uestioned by Dr. Robert Furstenau of sensitive to moisture, and that the elec- weighed. Berlin, who, in experimenting with hun- trode material may have peculiar puzzling The radioactive substance, .\ctinium, also dreds of selenium cells with similar bridge effects, is fairly well understood, and these gives off an emanation, whose activity dies arrangements as Greinacher, liad never no- features may explain some of the contro- in a few seconds. Poloniiun likewise un- ticed anv of these effects. Furstenau sug- \crsial statements made from time to time. 208 THE ELECTRICAL EXPERIMENTER July. 1917 k^TENTS

Electric Light for Razors Galvanic Cell connected with binding post 10 by Radio-Telegraph Receptor flexible conductor 1 7. (No. 1,224,499; issued to Greenleaf issued to Katherine (No. 1,221,062; issued to Morduch (No. 1,223,305; Whittier Pickard.) E. Allport.) L. Kaplan.) An improved method of receiving to of cell Alternating Current Rectifier At last an inventor has come New design miniature dry radio- telegraphic or telephonic sig- of the long-suffering as used particularly for flash-lights. the rescue (No. 1,221,981 : issued to Thomas nals wherein (Fig. 1) the secondary bath-room barber and here provides Use is made in this cell of a higher A. Edison.) coil C has only one side connected light attachment oxid of manganese, which appar- a simple electric simplified form of vibrating to the receiving apparatus D-T, ently consists of manganese in two A rectifier for charging storage bat- which may be grounded. Fig. 2 or more stages of oxidation, and in teries, etc. It involves a permanent shows a like arrangement except a peculiar form whereby extremely that the coupling between aerial A satisfactory depolarizing action is and primary B is made inductively. secured, and whereby it becomes Fig. 3 is similar to Fig. 1, except possible to concentrate and compact that two primaries B and Bl are tinely-divided grafite or other suit- used. T may be a telephone re- form of conducting able carbon with ceiver, and D a crystal recti fj^ing such a quantity of the depolarizing detector. Coil B is of sufficient length to cause its natural period to be equal to the shortest desired wave length. The secondary C, is adapted to slide in the primary B, Ft^l steel polarizing magnet, a set of vibrating reeds and an actuating so that one may see at all times magnet coil. The contacts on the on any part of the face, which is vibrators and fixt electrodes are of usually difficult with the ordinary special carbon to cut down arcing source of illumination, due to and sticking of contacts. By con- shadows. She also provides a neat necting the rectifying contacts in combined razor and battery cabinet, parallel a large current capacity is the lower part containing a suitable obtained; in series a relatively nigh dry battery, with a flexible cord to potential current can be handled. connect the miniature lamp with the The amplitude of movement of the battery. A new battery may be vibratory contacts is small— about quickly placed in the cabinet by 10 thousandths of an inch. means of a sliding bottom. The device would seem of extreme value lonized-Chamber Device to all military and traveling men. (No. 1.222.QI6; issued to Clifford The Electrolytic Rectifier Dudley Babcock.) (No. 1.223.114; issued to Charles C. A clever arrangement for ionized- chamber detectors or amplifiers of Ruprecht.) and consists of but a few turns of the de Forest type, and here shown An improvement in the design of coarse wire having a natural period in a de Forest radio receiving cir- electrolytic rectifiers which con- much smaller than the shortest de- cuit. The inventor simplifies the duces to the thoro circulation of sired wave length. construction and gains the advan- the electrolyte solution, as the ar- tage of having a finely adjustable Aerial Torpedo Steering Device «r^^ variable condenser incorporated in the device itself, by means of two (No. 1.222,630: issued to Lemuel John Husted.) A unique idea involving the use of "magnetic attraction" to actuate a special rudder control switch so as to cause an aerial torpedo or compound that long life of the cell similar projectile to unfailingly is assured. The inventor has found reach its target when the latter is that a lower oxid is desirable in composed of a steel or iron shell combination with the higher oxid, to structure. The lower part of the assure a novel and pronounced depolarizing action. He claims by this means a certain measure of transference of oxygen from the interior to the exterior of the cell, rows in diagram illustrate. The so that depolarizing efficiency does nietal electrodes 7 and 8 are placed not depend merely on surface ex- in a small chamber which com- posure, but also on the gross municates with amount the main circulating of the manganese compound. chamber thru two ports, the solution continually rising, due to heat- Electric Interrupter metal sleeves placed inside and out- ing, and passing salts thru the de- side of the tubular glass bulb. The posited in the lower (No. part of the 1,224,570; issued to Stuart inner sleeve supports the usual grid pocket formed by diagonal grid as Sandreuter.) and is charged thru the glass indicated. The inventor claims An electric interrupter intended dielectric from the outer sliding that the solution will thus be kept metal sleeve, connected in the circuit saturated at all times and that heat- as shown. ing is reduced to a minimum, with increased efficiency in consequence. Undamped Wave Receiver Night-Sight for Firearms (No. 1,224,343: issued to James O. (No. 1.225.592; issued to Britannio Watkins.) Solaro.) The "tikker" apparatus comprises A clever invention of particular a suitable base and upright members value at this time and involving the of small size, and which serve to use of special back and fore-sights support adjustably a metal wire or for rifles or other firearms, each string. The tension of this string sight being provided with chambers IS adjustable by raising or lowering

for low freciuencies and comprising an insulating disc which carries a ring of conductive material provided with a plurality of radial exten- sions between which are mounted insulating strips or segments. The disc shaft may be driven by a motor or other device in order to rapidly or cavities enclosed by a lens, and rotate the same. Contact with the adapted to contain a salt of radium rapidly rotating segmented metal which will emit rays of light, these ring is eff'ected thru a spring actu- being concentrated as a spot of ated rolling wheel. Connection is torpedo contains a charge of explo- li^ht by the lens in each case. made with the segmented perifery sives to he detonated by an electric When the back-sight and fore-sight of the rotating disc by means of a a pointed tension block A, by means fuse 10-U, operated by switch 15, are applied to a rifle, as shown, it suitably proportioned metal wheel of thumb screw B. The string is when the missile strikes its target. becomes evident that the ordinary 14. This is pivoted in a sliHinp vibrated at radio frequency by The inventor provides an "attrac- sights of the rifle will not be ob- metal block U, constantly pusher! means of a smooth -edged disc tion" electro-magnet 9. suspended to structed. forward by a spiral spring 1 S, and mounted on the shaft of a motor. swing in any direction. COPIES OF ANY OF THE ABOVE PATENTS SUPPLIED AT 10c EACH July. 1917 THE ELECTRICAL EXPERIMENTER 209 Phoney Patent Offizz Under this headinfr are publisht electrical or mechanical ideas which you haven't a smell of the Patent yet. After they have allowed the Pat- our clever inventors, for reasons best known to themselves, have as yet ent, you must pay another $20.00 as a final fee. That's $40.00 ! ! WE not patented. We furthermore call attention to our celebrated Phoney PAY YOU $3.00 and grant you a Phoney Patent in the bargain, so you Offizz for the relief of all suffering daffy inventors it) this Patent country save $43.00 I ! When sending in your Phoney Patent application, as well as for the entire universe. be sure that it is as daffy as a lovesick bat. The daffier, the better. We are revolutionizing the Patent business and OFFER YOU THREE Simple sketches and a short description 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 a Patent to Washington, they charge you $20.00 for the initial fee and then jiffy.

Lapup Cowjuce of Milkshake, N. D. Patent Appraised -(^^) CUDOMOTOR

To ll'lionic It May Constern: away (patent applied for). To her jaws Galena is used on the stop-cock because it lie it appraised to all cows, calves, dair>-- are now attached jaw clamps A. These in is very sensitive. The oscillating air next mcn, dairymaids, dairyoiiths, dairywomens, turn are attached to a scissor-mechanism B, flirts into the quartz pulsator U, from which and all others interested in the lacto indus- pivoted on silk ball-bearings as shown. It it escapes to liberty. This creates a pulsat- try, that I, Lapup Cowjuce of the City of becomes apparent that as the cow chews, the ing vacuum in the scanatory Bakelite milk Milkshake, in the State of N'ervous Depres- scissor mechanism is given a reciprocating can R. But as the latter is connected by sion, have at tlie risk of my decaying sanity, movement. This motion is transmitted thru means of a flexible hard-rubber tube T, to in\ented an

" . . .1, Lapup Cowjuce of the City of Milkshake, N. D., Have at the Risk of My Decaying Sanity. Invented and Designed a World-Upheav- ing Device. Whereby It Is Made Possible At Last for Cows to Milk Themselves Automatically By the Surplus 'Cow-Power' Developed By Their Constant Cud-Chewing."

.•\s is universally known among cows and of Dynamo G. This latter on account of the 1st—.\n automatic cow-milk dispenser, dairypeople, cows continually "chew their oscillatory moving jaws of the cow, gen- dispensing with all milkmaids. cud." Here we have a constant form of erates an oscillating alternatin.g current, 2nd —A cow-milker operated by the cow's energy, which has been calculated to repre- which then charges the alternating current own cud-chewing. sent about 9' 4 cow-power per da\-. It has storage battery H. This resulting current 3rd— .\ motor attachable on all rumina- also been calculated that the cow to chew oscillates thru the Tungsten switchboard I, tors and other rummies. the cud efficiently only requires S-'i cow- and thence thru the connecting platinum In memoriani henceforth and hencewith I power. This leaves a net wastage of 4 C.P. cables .1. The current then drives the bash- have therefore caused and bv these presents per day. This totally wasted energy I have ful motor K which now operates the anaemic do hereby depose upon this legal instru- now at last harnest, in as simple as it is hot-air compressor L. The resulting com- ment my south-western uppermost back- efficient manner. Xot only do 1 use this prest and perfumed air is then stored free hoof, this 3rd day of our Grace, in the 149th energy to milk the cow itself, but I use it of charge in the leather tank M. Hot wire year of the French Revolution. also to light the house, run the butterchurn- ammeter X is used to observe too high a Fiiiicssi-s: Lapup Cowjuce, er as well as the bultcrmilker. temperature. The air is now conveyed thru A. Helnvaguy. By his attorney: First the cow is secured properly to a glass pipe O, thru Galena stop-cock P, A. \\. Drvup, Leon'.\rd S.arves, simple mechanism to keep her from backing thence thru flexible cast iron supply pipe Q. S. O. Mecrust. Enid, Okla : : : ; :

210 THE ELECTRICAL EXPERIMENTER July. 1917 Question>y^r^ Box

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

BUZZER TELEGRAPH SYSTEM. Q. 1. What is the chemical symbol for as much capacity as possible in order to Warren, Detroit, Mich., (801.) O. M. 'Qxybenzylmethylenglvcolanhy dride" ( Ba- obtain the maximum efficiency therefrom, asks kelite) ? and when combining the two conductors, it possible Q. 1. Would be to use the A. 1. At the present time there is no the capacity is increased. A single wire following scheme to telegraph a distance chemical symbol to the Bakelite as the 100 feet long is desirable for receiving of a block or two ? chemical decomposition of phenol, which purposes, as the capacity of such antenna is the ingredient used in the making of is uniformly distributed and at the same this compound is still a puzzle to the mod- time the inductance is increased, which ern chemist. It is one of the most diffi- permits finer, tuning of received signals. cult problems of, the chemist to obtain the Q. 3. Is it possible to make an electro- Ij-tic interrupter for a spark coil operating |lllllllll!rilllllll!llllillllllliiillliiiiii!l!!!lliiiliin^ on 110 v^lts A. C, and if so, how? a ODD PHOTOS WANTED AT m A. 3. X'es. An electrolytic interrupter $1-00 EACH!!! for this purpose can be made by placing a ^ I a lead/electrode in a container and adding = Now is the time to make your B solution , a composed of one part of sul- g Kodak pay for itself in a real practi- B furic acid and nine parts of water. cal way. IVc are after interesting A a H second electrode, made of small diameter m, photographs of out-of-the-ordinary = iron , wire is placed perpendicularly to the J electrical, radio and scientific snb- s first electrode, as shown, taking care that J jccts and are zeilling to pay $1.00 cash g they do not touch each other. It is pre- for every one 'u'c can use. Please a H ferable to enclose the iron wire or electrode H bear in mind that for half-tone re- M ' of smaller surface within a porcelain tube a production in a magazine, a photo- B having a small orifice at the lower a graph should be particularly sharp B end, An Effective "Buzzer" Telegraph which will just pass the wire. With the System g and clear. Of course, if a subject Which Employs Two "Ground" Plates at ^ iron wire relatively very small as com- Each Station, Each = happens to interest tis particularly = Plate Buried at a Differ- pared to the surface of the lead electrode, ent Level. A Radio Detector, Fixt Condenser a well, we can have the photo retouched. B and Telephone and with the applied potential and current Receiver Are Used at the Re- = For the general run of subjects, hozi>- ceiving Station. B critically adjusted, as well as the induct- ^ ever, it does not pay to go to such 3 ance and capacity of the = expense. Therefore, please take pains circuit properly A. 1. Yes. You will have no trouble in H balanced, an yinterruption ' '" properly focus and crpose your action can be transmitting consideralily more than the S M effected. distance you mention. J pictures. It often happens that a M / = really mediocre subject well photo- The interrupter is theti connected in the Q. 2. If possible would a tuning coil or M graphed wins approval over an e.v- usual way ^nd the wiring diagram here- loose coupler connected in the receiving a M = cellent subject poorly photographed. with gives /the proper' connections. The circuit improve it ? B And don't send us plate or film "nega- choke coil which is connected in the pri- A. 2. A tuning coil or loose coupler g W tiz'es:" send unmounted or mounted mary circuit should consist of an iron wire should not be used with this system, as a H "prints," preferably a light and a dark core one inch in diameter and 12 inches it is impossible to tune any distant signal ^ 3 one. long. Twb layers of No. 14 D.C.C.-mag- with this ground telegraph system, speak- a M _ M As to what to photograph: Well net wire are wound on it. This coil should ing generally. , M a that's hard for us to say. We leave 3 ' invariably be used, as considerable trouble ADHESION PHENOMENON. is that up to you, and every reader now I encountered in running electrolytic in- (802.) Betram Wertheim, N. Y., writes a g has the opportunity to become a re- terrupters on alternating current. us g g B porter of the latest things in the realm M 1. Whenever, after carbon Q. typing a of Electricity, Radio and Science. copies, I find that a strange phenomenon B B'lt, please remember— it's the "odd, = occurs. The papers, including carbons, a the novel or practical stunts" that we are H are charged with static electricity and they a g interested in. Every photo submitted all adhere to each other. The most pecu- J g should be accompanied by a brief de- g liar thing about this phenomenon is that g scription of 100 to 150 words. Give M all the papers seem neither to be charged 110 V AC. the "facts"—don't worry about the S negatively or positively, but neutrall}-. No a a style. We'll attend to that. Enclose g matter how I change their positions to g stamps if photos are to he returned g each other, they always attract. I there- Of^d place a piece of cardboard in the B fore come to the conclusion that they must a a envelope with them to prevent mutila- M be charged neutrally, or by some new form a SOS cno.ire CO// a tion. Look around your tozcn and H of static electricity. , see what you can find that's interest- a A. 1. The peculiar phenomenon which a Simple Electrolytic Interrupter for Use on Alternating you have observed with the paper Current Circuits with Spark sheets H To give some idea of the freak S Coils or Open Core Transformers. is due directly to the adhesion properties of a photos we like—refer to page 188. H air when it comes in contact with paper Address AUDION CIRCUIT QUERY. atid w^hen the papers are separated, they photos to—Editor "Odd m Photos," Electrical Experimenter, (804.) Oscar F. Miller, Milwaukee, stick to each other. .\ similar experiment m. m Wis., 233 Fiiltoji Street, York City. says can be demonstrated by placing a sheet of New m paper on a flat table and quickly lifting Q. 1. I have a receiving apparatus com- iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii it posed of the up ; you will observe that the paper will following: —Audion detect^ir, tend to stick to the tal)Ie. This is due to symbol a{ an organic compound, and 4,500 meter loose coupler, 6 volt—60 amp. the adhesion hour storage battery, properties of air : also a par- Bakelite/is one of these. Brandes' 'phones, an tial aerial vacuum is usually created. There is Q. 2. XVhich is the best, an aerial of 150 ft. long, 4 wires, which gave nothing electric about it. two wires fifty feet loiig, or an aerial of very poor results. The Audion (de For- one wife one hundred/ feet long? Wliy? est tubular type) has been tested and is I OXYBENZYLMETHYLENGLY- A. 2/ As to whether the antenna is to O.K. am sending a diagram of my set. COLANHYDRIDE. be used for receiving or transmitting, the Kindly advise me what you think my trou- (803.) Harold Betts, Sacramento. Cal., two wires 50 feet long are better for the ble is. wishes to know latter purpose, as the antenna must have A. 1. The trouble is with your wiring : : — —

July. 1917 THE ELECTRICAL EXPERIMENTER 211

diagram, and the only way to remedy it is to connect the filament terminal with one leg of the secondary of the coupler, and disconnecting the "B" battery terminal with the leg of the secondary, as you have it at present. BOOKS (805.) H. H. Bales, Halifax, N. F., wants Q. 1. The prices of the following text

hooks : "Alternating Current Electricity and Its Applications to Industry"—By \V. H. Timbie and H. H. Higbie, 729 pages. Second Course, 1916. Also "Practical Electricity." Latest edition, published by the Cleveland Armature \\'orks. A. 1. The price of "Alternating Current Electricity and Its Applications to In- dustry," is $3.00, and "Practical Electricity" is worth $2.00. These books, as well as any others, can be obtained thru our "Book Department," by sending amounts stated. • TELEPHONE MAGNETS. (806.) A Reader, Otsego, Michigan, wishes to know Q. 1. How can I magnetize telephone magneto magnets ? A. 1. The magneto magnets can be re- magnetized by employing an electro-magnet consisting of two poles ; the distance All About Electricity between these poles should correspond to the distance between the magneto mag- Anythmg you want to know about electricity can be found in these seven thick volumes. thru the understand. The net poles. By passing a current Every line is written in plain language—language that ever\'one can electro-magnet and holding the same against 1916 edition—just off the press—covers the generation and use of electricity for power, of the poles of the steel magneto magnet, light, transportation and communication, including the construction and operation so as to permit the magnetism to flow into dynamos and motors. Also covers central station engineering and telephone work, as well the poles of the permanent magnet, the as wireless telegraphy and telephony and land and submarine telegraphy engineei; latter will be revitalized. The N. pole of Valuable alike to the electrical experimenter, experienced electrician and electrical the electro-magnet should be placed against Electrical Engineers earn from $150 to $250 a month. the S. pole of >he magneto-magnet. w-i

ment, we are very much in doubt as to N'AMB ..... whether it can be done, but by the employ- Addkess., ment of an Audion detector, a variable American Technical Society condenser shunted across the secondary of U. S. A. the inductive coupler and a pair of 2.000 Dept.E744BChlcago, ohm 'phones, you should have no trouble ,^J

yon benefit by mctitiotiitty "The Electrical Experimenter" when writing to advertisers. : : —

212 THE ELECTRICAL EXPERIMENTER July, 1917

in receiving Arlington or N.A.R. But bear BACK TO THE DAYS OF VOLTA. in mind that during the war, no wireless (Continued from page 172) outfits can be operated, by anyone. Mesco Wireless Practice Set Volta was one of the most prolific in- WIRELESS TELEPHONE CON- ventors of all times. He invented a greater For Learning the Wireless Code NECTION. amount of basic electric apparatus than any other living scientist with the exception of (807.) Ivan Bulock, Fairmont, Minn., Faraday. In Fig. 3, at the left is shown a writes clever apparatus which when energized by Q. I. Which is the best way to connect static electricity produces imitation hail. an ordinary carbon grain transmitter on Fig. 3 (at right) shows his apparatus for 110-volt., 6 amp. d.c, for wireless tele- exploding a mi.xture of oxygen and hydro- phonj- ? gen by means of an electric spark. A. 1. The accompanpng wiring diagram shows the best way of connecting such a LIGHTNING—HOW TO PROTECT transmitter. YOURSELF FROM IT. Q. 2. Could an ordinary one-inch spark coil be used as a transformer for wireless {Continued from page 175) The Practice Set comprises a regular tele- telephony ? are dry. But let the hand be wet with graph key, without circuit breaker, a special A. 2. No. The current obtained from the water or with perspiration, or let the per- hiRh pitch buzzer, one cell Red Seal Dry secondary of a one-inch spark coil is so son stand on floor Battery, and four feet of green silk covered damp or ground, then flexible cord. small that it does not warrant its use. enough current max- pass thru tlie heart to The key and buzzer are mounted on a paralyze it, and death will occur suddenly. highly finished wood base, and three nickel Most fatalities from industrial currents plated binding posts are so connected that come from those at 500 volts to 5,000 volts the set may be used for five different purposes, as illustrated on page 24. pressure. People who have received shocks For the beginner, the set is of exceptional VWW^ from a 10,000 volt current have lived. value, for it may be used for individual code At low voltages the alternating current is practice or for operation of a two party line, / which is an excellent method of quickly //OKBC CMecoih. three to four times as dangerous as the learning the code. After the beginner has direct current, but at high voltages the mastered the code, the set may be used in I direct current is the more dangerous. It his wireless outfit for setting the detector in adjustment, and also the key may be used VWWV MWMr-^ is safe to pass a current at several hundred to control the spark coil. thousand volts pressure thru the body if Recommended for schools, as it gives ex- j-A/WWVS there are over 10,000 alternations per sec- cellent service for class instruction in code ond. Three-tenths of an ampere causes work. Full directions with each set. Transm. death at low rate of alternations but three The main object of the set is to enable the SOT beginner to master the wireless code, and © amperes can safely be taken if the alterna- the buzzer reproduces the sound of the sig- tions are half a million per second. With Hook-Up for Wireless Telephone Arc Circuit nals of the most modern wireless stations Microphone Inductively Connected to wet hands and feet the resistance of the perfectly. with Control Oscillations. human bodj' may be from 1,000 to 1,500 Every beginner needs one of these sets, olims. This is not much of a resistance and as it is the equivalent of five different sets, the price is very low. WHAT IS SYNCHRONISM? for the lightning at its greatest pressure List No. Price. (8U9.) H. Somerfelt, Butte, Mont., asks: to overcome. A person standing isolated 342. Wireless Practice Set, with Battery Q. 1. What is meant by synchronism? on moist soil makes an attractive target for and Cord $2.25 A. 1. This term may be' defnied as the the lightning. 344. Wireless Practice Set only, no bat- simultaneous occurrence of any events. tery or Cord 2.00 two There is a superstition that lightning said Thus two alternating curren/s are to figures, found on the skin of a person lie in synchronism when they have the same Send for Our New Edition of our struck by lightning, are mysterious photo- frequency and are in phase: graphic reproductions of trees, landscapes Catalog W28 Ready June 15 Q. 2. For what service/are the 25-cycle or objects in the neighborhood at the time and 60-cycle currents adapted? It Is pocket size, contains 248 pages, with over 1.000 the person was struck. But the various Illustrations and describes In plain, clear language A. 2. The 25-cycle frefluency is used for figures produced doubtless show the distri- ail about Bells, Push Buttons. Batteries. Telephone and Telegraph Material. Electric Toys. Burglar and conversion to direct currents, for alternat- bution of the high potential electricity in Fire Alarm Contrivances. Electric Call Bells. Electric ing current railways, aîd for machines of and the Alarm Clocks. Medical Batteries. Motor Boat Horns. passing along a poor conductor Electrically Heated Apparatus. Battery Connectors. large size ; the 60-cycle frequency is used consequent burning along a ramifying path. Switches. Battery Gauges. Wireless Telegraph In- for general distribution for lighting and struments, Ignition Supplies, etc. The telephone instruments and users to power. / IT MEANS MONEY SAVED TO a large extent are protected by use of a YOU 3. must ^n alternator be con- Q. How device the lightning arrester. This con- to have our Catalog when you want to buy. structed to generate! two-phase current? sists of a ground wire coming close to the K. 3. It must hiave two independent telephone wire but not quite touching it. Manhattan Electrical windings, and theie must be so spaced The gap between is enough to prevent the the £.M.F. generated in Supply Co., Inc. out that when one current used in telephoning from passing of the two phases' is at a maximum, the New York: Chicago: ST. LOUIS: across to the ground, but when the wire E.M.F. generated in the other is at zero, 17 I'ark Place IH S. oth Ave. IIOS I'liie St. receives a high charge from lightning, the I. c. they are 90 degrees apart, vectorially San Francisco Office: GOi Mission St. potential is so high that the charge easily speaking. jumps across the gap and passes to the SOLDERING QUERIES. ground instead of passing thru the instru- (810.) Paul Johnson, Poughkeepsie, ment and finding some other passage to the Electric Row Boat Motor X'. Y., wants to know earth. You will observe that telephones Maiicyour Boat Row Q. 1. What is hard solder? properly installed in your homes are not an p:k-itrlc Launch. liuvaJ^nvt'l Detachable .\. 1. .^n alio}' composed of copper and placed where a person in using them could I by I H.);U Mutorrun Row silver. electricity. No odor or zinc, or copper, zinc and Hard at the same time make contact with a [ — dangerous casoline. (Continued on page 2131 register, radiator, or water-pipe. "G. S. Q." Simple, noiseless 1 ana powerful. Attaches to any Row Boat and runs on two Bis MAGNETIC ^*-~^~~~-~-_ vnlt Batteries. Tkis la ourStb RECTIFIER successful year. ^mLi^S^M F-F BATTERY BOOSTER OPEN WINDOW BATTERY Keep vour storage battery fully charged if Look inside your storage battery through the you'd get the most out of it in service and patented open window. See condition or (enpth of life. plates and heleht of electrolyte. If you need a convenient 110 volt 60 cycle new automobile starting Battery buy a Jewel Plug into any and save money. 6-60 Special SS.50. alternating current lamp socket and connect the Motorcycle Electric Li^htin^ System charging leads to the battery terminals. The Jewel Generator Motoreyclo8torace Battery and The rectifier utilizes the Full Wave of cur- complete Ifehttng.systera ia in Rre;it demand. Agents rent, has Carbon Electrodes and makes Re- wanted. Write lor prlcrs anr) calalOE K. ^ charging a Profitable Business where batteries JEWEL ELECTRIC COMPANY. 112 N. ritth Av., CHICAGO Nk are taken in to charge. \y SIS Complete P- O. B. Cleveland .ST) ^>t Biillftin No. 12. STROMBERG - CARLSON ftO.25 C^^^^^^^Û^^^^^^Î^^^B^^^r- RADIO HEAD SET '•'*' W THE FRANCE MANUFACTURING CO^ Oeveland, Ohio ^33 Jobbers and P

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213 July. 1917 THE ELECTRICAL EXPERIMENTER

QUESTION BOX. {Continued from payc 212) snkler is sometimes erroneously called sfi-ltcr. ELECTRICflkEXPERIMENTERS DEMAND Q. 2. What necessary rclatitCn must exist between solder and the' metals with which it is to unite? A. 2. The solder must have a lower melt- joined to LDSEAL^ ing point than the metals to be as it. The melting point should approach /' nearly as possible that of the metals to be FOR STRENGTH i joined, so that a mbre tenacious joint is effected. Q. 3. What does soft solder consist of and for what purpose is it best adapted? A. 3. There are two classes of soft solders, viz., common or plumber's, and medium or fine. These consist chiefly of FOR tin and lead, altho other metals are oc- IGNITION AND melting point. casionally added to lower the SERVICE REQUIRING Those containing the most lead arc the cheapest and have the highest melting HIGH AMPERAGE point. Common or plumber's solder consists of one part of tin or two parts of lead, and melts at 441' Fah. It is used Tne< .t»r'»" by plumbers for ordinary work, and occasionally for electrical work where wipril BATTERY WITH joints are required; for instance, in laii;i- lead-covered cable work. Medium or line GOLD SEAL solder consists of equal parts of tin and a WONDERFUl- lead, or half and half, and melts at 370' Fah. This solder is used for soldering RECUPER/ITIVE joints in copper conductors, and for soldering lead sleeves and lead-covered wires. A^ • POWER •• MdNU F/)CTUnC D OY

I ELECTRO-THERAPEUTICS. THE GOLD SEAL BATTERY CO. NEW YORK CITY (811.) Thomas Holdstern, Little Creek, Mich., asks

Q. 1. What is the true definition of the term "electro-therapeutics" ?

A. 1. The term electro-therapeutics is defined as the treatment of disease by elec-

tricity ; it embraces the laws, principles and doctrines of such treatment. Electricity is of special v-alue in the treatment of various VIOLET- RAYS! forms of nerve tension. The kinds of electricity used may be classed as follows NEW LIFE, POWER, HEALTH and BEAUTY in

1. So-called static, generated by Wims- the marvelous delightful VIOLET-RAYS. Newest hurst machines. and most powerful form of electricity, causing neither 2. Current, which is derived from two muscular contraction nor pain of any kind. sources, namely, primary batteries, which current is technically called galvanic current and second the faradic currents (pro- THE VIOLETTA induction coils). duced by secondar\^ High frequency instrument is endorsed by thousands of Physi- 3. Radiant energy, which is generated by cians who use it daily. radio-active sul)?tances such as radium and Produces SOOTHING, INVIGOR.\TIXG, CUR.\- radium ores, and X-rays. We may also TIVE VIOLET-RAYS, ^^onderfully quick results add the curative powers of radiant energy obtained in treating SCALP, FACE and BODY. generated by our distant sun. Health bringing OZOXE forced into the blood, proof VITALITY. Q. 2. What is meant by an interrupter- ducing an abundance less transformer as used in X-ray work? Sent on Free Trial

A. 2. This is nothing more than a high- Simple in construction and operation. The VIOLETTA tension rectilier wdiich converts the high- is especially adapted for personal use in the home. tension alternating current generated by Will operate on alternating or direct current or battery. the transformer into a uni-directional cur- ABSOLUTELY SAFE and GU.\R.\XTKED. rent which is fed to the X-ray tube. This Write for New Free Book rectilier is a four-electrode wheel rotating Send for our new beautifully illustrated book on VIOLETTA. what scien- on the shaft of a sjnchronous motor, and Tells all about the mnrvels of Violet-Rays. Read tists and doctors have to say. Post card brinRS book and all the direct current is obtained from two particulars ot special low price and free trial otTer. fixt electrodes stationed the near revolving Dept. disc. ""^^ BLEADON-DUNN CO. l-\ 208 NORTH FIFTH AVENUE, CHICAGO GOVERNMENT INSTALLS LAMPS TO PROTECT OHIO RIVER BRIDGES. Laboratory Research Wins Battles. Read The Federal Government has purchased impression. $1.50 ten searchlights for use in illuminatini; ap- "EXPERIMENTS" ^TV^lTrrV!'' E D E L M A N The applications proaches to the bridges over the Ohio River —the book ih.it .iw.ikcnc.l C'.rcnt Britain to the need of organized research. researches arc made, how research is organized, at Louisville, Ky., all of which are imder of modern scicnlilic wonders, how inventions and labyrinth of chemistry, electricity, mechanics, and modern physics arc clc.irly set forth guard. Another of the lamps has been the same and made obvious to yon bv this important work. installed on the roof of the City Mall in Edelman's "Experiinent.il Wireless Stations" 272 pp. 1917 impression $1.50 prepaid. Louisville and is used to ilhuninate the flat: PHILIP EDEI.M.VN, Publisher 1802 Hague Avenue, St. Paul, Minn. at night.

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214 THE ELECTRICAL EXPERIMENTER July, 1917

THE U. S. SIGNAL CORPS WANTS YOU! ^5^-^=^^ Junior Deaf-Phone KS7HLin, (Continued from payc 179) THE MICROPHO JUNIOR DEAF-I'HONE is a super-sensitive instrument which providing the men show ability and qualify." has Ijeen developed to meet the demands for a practical and efficient hearinK The following information is piiblisht to device at an extremely low price. It is equal to any $35.00 instrument made and superior to most of them. answer, in general, inquiries regarding the The outfit consists of One Super-Sensitive Signal Enlisted Reserve Corps. The En- Transmitter with cord connector: One Super- listed Reserve Corps is authorized by sec- Sensitive Ear Piece with small black cord ; One lilack ."Single Headband: Black Case and Two tion 55 of the National Defense Act, ap- liallerii IMPROVED proved June 3, 1916, the purpose or oliject being to secure an additional reserve of Super-Sensitive Microphone Only $7.50 enlisted men that could be brought to the is offered at an extremely low This instrument aid of the Government in time of national price. It is excellent for building your own radio amplifier. Can also be used in many experiments crisis. Applicants must be citizens of the nvliere a sensitive niicrupbone is required. L'nited States or have declared their inten- NEW DETECTAGRAPH $15 tion to become such, and must be between This detecting instrument of marvelous sensitivity the ages of 18 and 45 years. can be used for detecting secret conversations. Out- The responsibilities assumed by men en- fit consists of Sensitive Transmitter. 25 ft. Black Cord, Receiver. Headband, Case and Ilatltry. listed in the Reserve Corps are as follows : $15 Send lor one Today and Convince Yourself DETECTAGRAPH They are subject, in time of peace, to duty President MICROPHO-DETECTOR COMPANY Gaston Boissonnault, in instruction camps or elsewhere, for fifteen 26 Cortlandt St:, NEW YORK Makers of Super-Sensitive Microphone Apparatus days each year. They are subject to order to duty by the President whenever war is actual or imminent. The benefits conferred are:—Opportunity to render their most effective service to

Chemists Are More in Demand their countrj- in time of war ; opportunity to Be Prepared. Than Ever Before, No One Can prepare for that work beforehand by study and instruction ; rank in the Army of the Afford Not To Know About The United States and corresponding pay while Wonderful Science of Chemistry, on duty; the right to wear a distinctive iSend for ClieuKTaft. it is just niiat you need to start "rosette" or "knot" with ch'ilian clothing. your cheiiiical laboratory. You will learn thousands of valuable and interesting things, besides having all kinds Enlisted men of the Reserve Corps will be assembled in summer camps for fifteen CHEMCRAFT NO. I. PRICE $1.50. POSTAGE PAID ANYWHERE IN UNriED STATES OR CANADA. Con days' instruction each year, so far as ap- tains fourteen chemicals. Test Tubes. Glass tube. Measure. propriations granted by Congress will per- etc., and a valuable instruction book telling how to work 'Sij wonderful c-Xperinieiits in Chemistrj' and Chemical Magic. mit. Transportation to and from these CHEMCRAFT NO. 3. PRICE $5.50. DELIVERED EAST camps is furnished by the Government, also OF THE MISSISSIPPI. WEST OF THE MISSISSIPPI OR TO CANADA. $6.00. Contains 48 chemicals and lots commutation of subsistence at the rate of of extra apparatus, such as a Blow-pipe, Test Tube Holder, 50 cents per meal during the journeys. Test Tube Brush. Ah^ohul Lamp, etc.. in addition to the apparatus contained in the other outfits. With Chemcraft While at the camps subsistence is furnished Js'o. 3 yi)U can work more than 200 fascinating eiperiments. by the Government. Uniforms and equip- CHEMICALS AND APPARATUS FOR THE EXPERI- This picture shows Chemcraft No. 2. which con- ment are also provided by the Government MENTER. We have just completed a price list of chemi- tains 32 chemicals with complete apparatus and cals and apparatus for experimenters. Send 10c in coin for use while attending the of instruc- Instructions for working 85 experiments In Chem- camps or stamps for a copy of this List. It will be valuable to you. istry and Chemical Magic. Price, postage paid, tion. Reser\-ists are entitled to pay at the $2.50. West of the Mississippi and to Canada. $3.00. THE PORTER CHEMICAL CO. rate of their respective grades in the Reg- Dealers: Write for Discounts on the Chemcraft Line. Dept. B. Hagerstown, Md. ular Army during active service, including the time required for actual travel from their homes to the places to which ordered and return to their homes. *• THERE'S MONEYiN/T" The grades and monthly pay of enlisted men of the Signal Reserve Corps, according to the new schedule, are as follows : a«ri^Sm^LEARN TELEGRAPHY^gSH. signal electrician ** Master $81.00 —:^^ZniMORSE ANDWIRELESS-m:£p-" Sergeant, first class 51.00 Sergeant 44.00 Corporal 36.00 TEACH VOURSBUH Horseshoer 38.00 Cook 38.00 in half the usual time, at trifling cost, with the Private, first class 33.00 wonderful Automatic Transmitter. THE 0MNI6RAPH. Private 30.00 Sends unlimited Morse or Continental messages, at are the qualifica- any speed, just as an expert operator would. The following general tions requisite for enlistment in the Signal AdoDted by U. S. Gov't. 4 stylet. Catalogaa free. Enlisted Reserve Corps A. Master Sign.\l Electrician. The OMNIGRAPH MFG. CO. applicant must be 39L Cortlandt St. New York (a) An expert telegrapher and have knowledge of the construction, operation, and maintenance of telegraph systems, primary and secondary batteries, and motor generators, or (b) An expert radio operator and have knowledge of radio apparatus. of Radio You May Learn Theory, Code and Laws (c) Have knowledge of the con- Communication in Our School or at Your Home struction, operation and maintenance of telephone systems, fitting you for positions paying good salaries witli wonderful chance switchboards, of to travel the world over. It's the most interesting profession location troubles, repairs, primary and known and the demand for skilled operators is increasing. secondary batteries, motor Send stamp for catalog giving facts. Resident classes open generators, or Oct. :nd. (d) Possess such qualities as NATIONAL RADIO SCHOOL, 14lh & U Sis., N. W., Washington, D. C. would fit him to act as senior ,, », ^^"-- ^P"-!""' Advantages non-commissioned officer of WASHINGTON for These Courses. a company of Signal troops, to act as a leader.

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July. 1917 THE ELECTRICAL EXPERIMENTER 215

B. Sergeant, 1st Class. The applicant thru an approximate angle of 90 degrees must be cm either side of the vessel to bring a lurking submarine into its path, for the (a) An expert telegrapher and have knowledge of the opera- ray is already in the proper horizontal tion and maintenance of tele- plane beneath the surface of the water. It is operating only in one medium, water, graph systems and batteries, WANTED— Railway Mail Clerks or and the opatpie glow is not formed. Its color in contrast to the green sea enables Commence $75 Month (b) An expert radio operator and Increase to ** Franklin Institute it to be seen in bright daylight as a slender $150 have knowledge of radio ap- Dept. D104 reddish path extending some two miles out Common Educa- paratus, or Rochester, N. Y. into the ocean just beneath the surface of tion Sufficient of telephone Sure pay. -J^- Sirs: Send me. without charee, (c) Have knowledge the water. yjO sample Kailwi»y Miii! t'lerk El- systems, switchboards, bat- An observer with a powerful telescope Life job, 4^ amliiaUoa queaUons; MrhcduJe show- T>. of exainlnali'niB; list of teries, locating and correcting full.1, unnec- ^O tnit places is stationed aloft, whose duty it is to ob- ^ ^^j^,.^ gtntrnmeiit j<.l.^ n-w .asily ob- essary. and free book describing tliem. faults, etc., or serve vigilantly this tract of crimson as lainable (d) Possess such qualities as it sweeps slowly back and forth abreast of Name leader would fit him to act as the ship. Address of a platoon of a company of Suddenly he presses a button, instantly Signal troops. arresting the revolution of the beam of liglit, for he has noted that the ray of C. Sergeants and Corporals. The ap- light does not extend to its ordinary limit, RS plicant must have general knowledge while tliere is a glare of blurred light form- TO of the subjects given under B, or ing what may be termed a "bulge" in its 1 GREAT possess such qualities as would fit path and he realizes instantly that the OPPORTUNITY! him to act as a leader of a platoon or non-trans- liato fcllowing listed motors In Signal beam of light has encountered a We the section of a company of BtO'h. \V(- are dtsfr>ntlJiujn« these sizca parent body which is refracting the ray. troops. and offer them now ltEU>W COST. If you nc*d a The alarm is sounded and tlie gun battery good, brand new motor that ia'juat a little fibop worn Private. from haiidllnjr, in our stock rooms, thia Is your chancft D. Private, 1st Class and trained on the spot indicated. One or two Thew are all for 110 volts direct curreiil- Further The applicant must show an interest shots will destroy the menace and the ves- particulars may be had by applying to the undersiRned. 3—'^H.P. D. C. 110 volts, each $19.00: Hit price. in the subjects mentioned, be com- sel divert her course to clear it. may $24.00. 3— 'bH.P.. 0. C. 110 volts, each $9.00: list petent, keen, and possess such qual- All that is necessary to insure the suc- price, $15.00. I— 'jH.P.. 0. C, 110 volts, each $37.00: list price. $46.50. I — I I6H.P., D. C. 110 volts, each ities as will insure that he will de- cess of this method is the perfection of a $7.00: list price, $9.00. velop along the proper lines in train- searchlight of sufficient power and an ex- ing. perienced observer. Electro Importing Co. Applicants for enlistment as Master Sig- The public may confidently anticipate the V 231 Fulton Si., New YorkCily. N. Y. nal Electricians and Sergeants, First Class, rapid development of this system of de- Loo will be given an oral examination. Appli- fence, which will prove not only a mortal cants for enlistment in the other grades will blow to the submarine but a benefaction Driver Agents Wanted demonstrate to the officer designated to ob- to all humanity. The device here described mor^y^bh.p- tain recruits that they have the necessary is easily adaptable to either naval or com- ,oarcoamu«.«ni.OD^e». M, ««i>tBaremalun» Car* guar- Hv»-Pa«». i tires Bush qualifications. Applicants for enlistment in mercial ships and a vessel may conveniently anteed ©r muaer search-lights of this type two bacli. the Eastern Department should present carry four — hWrlt« atonce for two aft; one on either side mr iS-DBAe cata- themselves at 39 Whitehall St. (near the forward and loK and all partic- olaia. Addraaa J. Battery), New York City. of the hull in both positions. H. Boak. Fraa. D«pt, lit Deico Ignltlon-Elect. Ste- & Ltf. CUSPiJiT. Boah Temple, LOCATING AND DESTROYING DOES RADIANT LIGHT POSSESS BCBH nOTOB CUoSfO, T"'Tlit i SUBMARINES WITH A WEIGHT? RED LIGHT RAY. {Continued from page 168) PRO-ALLY or PRO-MOTION? {Continued from page 165) mysteries. Briefly, he allowed a beam of WHICH ARE YOU FOR? right angles to our course and she is light to fall on a suspended disc in a vacuum You can't settle Una war. but you CAN settle your yourself? Or your- thus in a position, broadside, to an ob- bulb, exhausted to the highest degree. In future I Are you FOB AGAINST self? "Pro" means "for"—are you FOB promotion server from our vessel; that is. the sub- such a vacuum the disc was repelled on the that will move you out of the rut and Into the place up where you'd like to be? marine is presenting the greatest sur- impact of a light beam, and its repulsion higher — "Motion" means "action." Pro- face of her bull to us and is in the most was measured by its torsional effect on the motion means ai-tion that gets some- favorable position for the visibility from suspending wire. This light-pressure at the wliere. Ynu can't have action without HEALTH. VITALITY and our vessel, if she can be rendered so by distance of the earth from the sun is small, STBEXGTH. You MUST haTO these go forvvard and Up I any means. not quite a milligram per square metre of to A clam has motion—just enough to A searchlight operated from aloft on the earth's surface, or roughly, 70,000 ooze 'round in the mud. its onl>' promotion is to Uie iJiowder, Don't be a ship defects prevent tons on tlie whole earth. The light-pressure our has two which clflin! Be a MAN with vigor and it from being succssfully used for this is applied only on the surface, and is pro- purpose of manluwd. Let me show ynu HOW! By the same metho

. .Thinness . .Rheumatism . .Despondenrj' marines. ture of light. Below are given a very few . .Obesity . .Heart weakness . .Poor Memory . .Headache . .General Health However, if we submerge our search- of the instances in which the elements are . .Nervousness . .Insomnia . .Skin Disorder* . .Increased Height by the strange force of light: light or, rather, its ray of light to a depth acted upon . Shoulders. .Muscular . .Indigestion .R4>und

.Constipallon . .St.HU" Shoulders Development of fifteen feet by installing the searchlight (1) Nitric acid is readily decomposed by . . .Short Wind . .Deformity . .Great Strcnirth

silver and . . in the vessel at this depth lielnw tlie water- light. (2) Silver chlorid, iodid . .Flat Chest .Rupture .Weight Liftiiig

. Colds . .Youthful Errors . .Advanced Course line, and flash a powerful beam of light, silver hromid are all chemically changed . .Catarrh . .Devitalizing ..Multi-Weight I.,<>!is«4 red in color thru a thick lens of glass on exposure to light. (3) Silver nitrat in . .I.img Trouble Barbell

. .Poor Circulation . .Impotency in the ship's side and out into the water, the presence of organic matter, looses its Name obtain several distinct advantages over oxygen and is reduced to the metallic state we Street the searclilight operated from aloft. by the action of light. (4) Mercuric oxid City State It is only necessary to revolve this light is decomposed by light. (5) The chlorids

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216 THE ELECTRICAL EXPERIMENTER July. 1917

and iodids of mercurj- and thallium are ter for their individual zi-eights have been decomposed by light. (6) Upon heating actually determined bj- mathematics. nitrogen chlorid and nitrogen bromid in In regards to the Alpha, Beta and Gam- sunlight, the mixture explodes with violence. ma-rays emitted by radium, it has been (7) A balloon containing hydrogen and conclusively proven that the Alpha rays chlorin will burst when exposed to the are streams of little bodies (matter) with sun's rays. (8) Selenium lowers its elec- a mass about twice the mass of the hy- trical resistance when exposed to light. (9) drogen atoms, flying off from radium with WIRELESS In the Crooke's Radiometer the pressure a velocity of 20,000 miles per second, while of light causes a multi-blade vane or wheel for the College or Prep. School the Beta-rays given off by this innocent- to rotate in a vacuum. man, High School graduate, etc. looking little pinch of salt, are actual material corpuscles, with a known weight, The U. S. Gov't needs you in its It will be noticed in the cases cited above that the group of elements known as the and a speed of over 100.000 miles per see- Naval Reserve, Naval Militia Halogens, particularly the silicr salts, are ond. This is now regarded as an estab- and Signal Corps. affected by the action of light, which acts lished fact, and such being the truth, it Attractive openings. Special in most instances like a reducing agent. is much easier to believe that a gas, such as light may be, could attain a velocity three months' Summer course Why the silver salts are singled out from all the other compounds and made an ob- of 186,000 miles per second, and still be starting June 25th prepares you ject of attack by the force of light is diffi- within the bounds of material matter. for either Gov't or Commercial cult to explain by the ether-wave theory. As will be noticed, it was the author's object Service. Endorsed by U. S. Gov't But if light were taken to be a gas, tlie to present a few arguments in favor of the material theory, and altho this and Marconi Co. Day and Eve- above phenomenon would be more easily the- understood by the simple fact that light ory has not come into general acceptance ning classes. scientists, is is then a reducing agent. The light-gas by it gradually gaining ground, and from the researches SEND FOR SPECIAL LITERATURE. theory must thus assume that light pos- being made on sesses properties similar to other gases, radium emanations and all forms of radio- activity, it appears that the EASTERN RADIO INSTITUTE such as chemical aftinity, a definite valency, electro-mag- or possessing the power of a catalytic netic-wave theory of light may have to 899B Boylston St. Boston a.yent. Such properties appear to be con- be confined to more reasonable realms sistent within the chemical effects of light it may well serve to explain wireless- as shown above. telegraphy and such wave-activities, but the strange, material .force known as "Light" As is well known, the element Selenium certainly demands a more consistent explan- possesses the peculiar property of chang- ation in view of its chemical effects. ing (lowering) its electrical resistance according to the intensity of the light cast upon it, and this strange phenomenon has LEARN been a strong argument against the wave WIRELESS theory, as it is almost impossible to con- This summer ceive of the so-called ether waves produc- U. S. BATTLESHIPS TO RUN ON THOUSANDS of opeiiitors are urgently ing such a tangible, material effect. Sev- LAND. the Government. In war and needed by eral theories have been advanced to ex- peace the demand has always greatly ex- ceeded the supply. Unusual opportunities plain this behavior of light. One is the {Continued from page 170) therefore await the well trained Radio Men. formation of conducting selenids under the Although we have trained more operators ner. The steering is equally simple and action of light. Another, the formation than any other private scliool in the East, efficient. By running one motor at a slight- of conducting crystals. Still another, that we can supply only one-tenth of the demand ly higher or lower speed, the ship must made upon us. it is due to electrolytic action and finally either turn to the right or to the left, New Day and Evening Classes forming the electronic theory which assumes the this month—Reasonable Rates—Large Labo- as desired by its commander. ratory— Complete Connnercial Installations. releasing of negative electrons, due to vibra- tar>- resonance in the atoms. I have pointed out in previous articles, U. S. GOVERNMENT INSTRUCTORS Dormitories Catalogue Employment that the monster wheel is tlic prime re- Again, it has been demonstrated that Y. M. C. A. Radio School quisite of all large war machines. A huge light has a strong effect on bacteria, such wheel, such as the ones here described, 14S East 86th Street NEW YORK, N. Y. as ferments. At the Paris Exhibition in will easily ride over the widest trenches. 1900, the powerful results of light were Ordinary shell holes will be negotiated as men with training are always la demand. Havine trained over forcefully illustrated by the culture of easily as a cart wheel runs over a hole in electrical;' 2000 younif men in the_paat 23 years in tho fandamentain of Applied Electricity. The Bliss Electri- pathogenic bacteria in gelatin in glass bot- the street due to a missing cobblestone. cal, School, with it^ wfl) fqiiirped shops and laboratohee, is peculiarly !*>•»( c-jursf in tles. Portions covered Well Qualified to yive n^fd Electrical of the bottles were Rivers will be forded easily, if there is a with dark paper, the bottles incubated at fair approach. Even steep banks will be ENGINEERING suitable tetnperatures in bright sun-light negotiated by running the craft diagonally IncludinfT Mathematics. Steam and Ga» En. and the contents afterwards completely thru the stream. Low hills will prove no fines. Mechanical Drawing, Shop Work and heoretical and Practical Electricity, in all sterilized. Wherever the dark paper had all. steeper branches, Students actually Construct dyna- obstacle at while ones can be mos, install wiring and test efficiency of prevented light action, dense colonies of climbed the ship in zig-zag electrical machinery. Course, with diploma, by running a complete bacteria could be seen, while in exposed line. parts the nutrient gelatin remained per- IN ONE YEAR fectly clear. Here again, light acts as a There will be less wear and tear, and gas, for it can be easily shown that sev- less shocks too when running over land 260 Takoma Avenue, Washington, D. C. eral gases such as oxygen, exert an in- than when fording a tempestuous sea. The fluence on the growth of bacteria. Only reason is that these huge wheels, just on WIRELESS OPERATORS a strong imagination could attribute these account of their size, are rather elastic. SEE THE WORLD results to wave forms in the ether, it would They "give" a good deal. Then too, the Positions always open. Good seem. earth as a rule is more or less soft. Thus salaries. Day and evening sessions. we get a double spring action. .\lso due Correspondence courses. Wireless In concluding, it may be well to take to the enormous width of the wheels dis- apparatus for home use. Send — up the question of the speed of light and tributing the weight over a area 6 cents in stamps for catalog. wide its relation to any of the accepted the- will sink into the softest earth Phila. School of Wireless Teleg. they not ories. speed_of light has been defmitely 10 Parkway BIdg., Philadelphia, Pa. The much more than a few inches. This ma\' accepted and proven as 186.000 miles per seem surprising, but a simple calculation second, and this tremendous velocity has which any engineer may make in a few been for years a strong objection to the seconds, will prove the statement correct. corf'nscnlar or material theory, as it was Commercial License imbelievable that any material form of It goes without saying that in order to Complete preparation in afternoon andevening classes* matter could attain such terrific velocitj'. carry the enormous strain, the .ship must Ask for folder "B" Of late years, however, there has been be strengthened by a good deal of cross- much progress made in the study and be- truss steel work, as indicated in our illus- Eastern District Y. M. C. A. havior of X-rays and radium emanations; tration. Otherwise the shaft would rip Marcy Avenue, near Broadway, BROOKLYN. N. Y. and it has been conclusively proven by clear thru the decks. This truss work, means of mathematics that the speed of however, should not prove over difficult, the corpuscles emitted by metals under the nor a very long-winded operation. The Learn Walchwork, Jewelrywork and impact of ultra-violet light, mav be taken reader has already guest that no new Fnuravino ^ ^^"^ trade commanding a fiood sal- as anywhere from 10.000 to 90.000 miles power plant is required. The old one is i-iiigi aviiig. ary^ ^^f^ your sen'ices are always in utilized, the ship burning demand. Address HOROLOGICAL Department, per sceond: and it may also be stated that of course coal Bradley Institute, Peoria. III., for our latest catalog these corpuscles are material atoms of mat- the same as if it were on the ocean.

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217 July, 1917 THE ELECTRICAL EXPERIMENTER

From a military standpoint, this mon- )r/^s;rF:!iri^SifîîPiS)?î'^^ ster engine (if destruction proves rather interesting. But let us sec what happens when the "Oregon." one tine summer morn- ing steams thru the I'reiich fields, "Old Glory" flying from hotli masts, and plow- AMATEURS! ing toward the German trenches. No more thrilling or awesome picture could he imagined. Of course long ere onr hattle- trenches, the ship has reached the first IVTOW is the time to overhaul your set and enemy aeroplanes have reported it. and the "Oregon' receives a warm welcome to buy your apparatus at a low cost. from the heavy enemy guns. But this the is just what we want. After finding Remember, the War won't last forever, and range of the enemy guns, our hattlesliip's 10-inch guns can either silence the enemy when the ether is free once more for all, YOU or otherwise run towards the German hat- first to listen in with a tery and crush it by simply riiiinini] over want to be the one it. There is no escape for them, for we REAL set. i have the advantage of quick mohility ( the ship runs from l.i to 18 miles per hour I against the slow mohility of the enemy Besides, there is the possibility that the Govern- guns, which cannot he moved quickly. ment will soon again allow us to operate receiv- .\ftcr annihilating these, the land monster runs amuck, destroying ammunition dumps, ing sets during the War. and raising general havoc hehind the lines. Small puns and machine guns prove of Are you ready ? little use against our armored hattleships, enemy and even if, as is to he expected, Write for our printed matter. shells find their mark, they cannot "sink" us or stop us. Fôr the engines as well Cal. as all other vital parts are protected by AudioTron Sales Co., 315 Lick Bldg., San Francisco, heavy armor. The wheels themselves will not be put out of running order easily, because they are not solid. The shells, even if they do hit. will hardly destroy the entire wheel. Beyond ripping out a STORAGE BATTERIES FOR ALL PURPOSES few steel beams, no great damage will be done. Better Batteries for Less Money The "Oregon" now runs over and par- V^t Backed by An Exceptional allel the trenches, the battleship's well pro- :^^ tected machine guns emplaced low down . Guarantee in the holds, firing away continuously. The 1-* Capacity result is that the enemy must give way. ^ The Mark-o'Quality hattleships are used simultan- ^ If several tlA- Quality Price eously in a grand attack, there is no question that the enemy must fall hack over §r? a wide area. tto WE MANUFACTURE BATTERIES .And it will be impossible for the enciny ^^ FOR EACH MAKE OF AUTOMOBILE to board the swiftly moving vessel. Even ^ 974 8th ATt.,N. Y.Ciiy if forced to stand still, its machine guns PAULM.MARKO SCO., Inc., 1191 Bedlord A»e., Brooklyn, N.V. N. Y.Depoi— and other guns would ward ofl^ all close attacks. There remains the aeroplanes dropping bombs into the ship. The answer here would be—anti-aeroplane guns, installedjd- UNIVERSAL ELECTRIC MOTORS ready on every modern war-ship. Besides OPERATING ON A. C. OR D. C. -110 TO 130 VOLTS our own aeroplanes would protect the ship 1/40 TO 1/8 H. P. CATALOGUE FREE off the enemy flj'ers. by beating THIS MOTOR Sf^. 00 1/20 H. P. 6000 R. P. M. V/ Complete with Puriey llriMK T'setl Sut-assfuUy for Grinding, Polishing. Priv- Emer> Wheel ing Small Jladiinerv. Sewing Machines, Fans. Wireless Sparh Buffing Wheel "HAM" JONES—SCIENTIST. Gaps. Elcrtrif Fountains. Check Endorsers. Huniiclors. Valve Chucks (Jrintiers, Elertric Hair Clii>i>cTS and numerous olher appliances. Cord and Plug {Continued from [

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218 THE ELECTRICAL EXPERIMENTER July, 1917

was on, and I cut both wires at once. There equipment and these should be of various PATENTS was some great fireworks, but those new dimensions capable of responding to a vide OFTEN the slightest Improvement, ,__ fuses of mine held first rate." Then he range of lengths. is ""Si tected by a patent, means thousan<^of wave It also desirable rlor"* doUars to the inventor. Our bulletins list laid them reverentl)- upon the top of the to build several fixt receiving condensers hundreds of invf ntii^na trreatly n@«ded, especially in electrical apparatus, auto accessories helix. of various capacities and eacli and household specialties and toys. Bulletins one equipt and book of advice free. Simply mail a post with a shorting switch. Detectors of vari- card. LANCASTER & ALLWINE "Hen" told me all about the mechanism Registered Af'ii''- ous types should also be on hand, as it 255 Ouray Building. Washington, D. of tlie curtain and then towed me back to the bed to show how he "turned in" and must be remembered that certain crystals "hit the hay." It seems he did not use are better adapted for some work than the curtain arrangement very often, for others. The Audion is not an absolute necessity it it had a habit of rising before the desired unless is desired to experiment with this particular instrument for regen- time ; however, all was ready for the dem- PATENTS erative work, etc. It might be said here THAT PROTECT AND PAY onstration. "Hen" was supposed to have said his prayers and be snugly tucked un- that the Audion and its circuits offer a very Books and Advice Free der the covers. fruitful line of research. At least three If you waDt to sell your patent, take It out through my variable condensers should be included in REFERENCES. BEST RESULTS. "Watch out," he warned, "while I press office. HIGHEST an experimental outfit, as they are very button number one." So he prest it and WATSON E. COLEMAN, Patent Lawyer necessary additions, absolutely essential for Street, N. Washinston. D. C. with a click the latch gave away and the 624 F. W. real serious work. door swung open. Probably the most important considera- "Now for number two," cried "Hen." IN PATENTS tion in wireless research work, especially in MONEY "Watch the curtain. This is the best of K We secure your patent or return our fee. "^ regard to receiving, is the rapid change of the whole bunch!" Tn'ang went the spring Send sketch or model for free search of Patent connections. Experimental apparatus report on patentability. of the curtain and up went the latter with Office Records and should be as flexible as possible. The sim- /Manufacturers are writing for patents secured through iis.1 a bang, but on its upward journey it struck plest to accomplish this is a toSecure Your Patent,' listj way to build IWrile for free book, "How and the end of the pliers which "Hen" had left of patents wanted. We assist in seUing your patent small switch-board and this should contain "^ sticking over the edge of the heli.x ; the p. a PATTISON & CO, U. S. P.i™i Attoraej. a number of single point switches, D. P. Bldj. WMtkiitno. D.C pliers sailed over toward the 110-volt 427 BmitUr S.T., D. P. D. T., and multipoint switches. switchboard and thereupon there occurred The points and blades of the switches a series of twangs and bangs intermingled L" p o n electrical ap~ should be connected directly to binding with shooting stars and meteors then [iliancea are in de- — posts on the back of the board. There Giand ; manufacturers something gave away and the Jones' house PATENTS are «Tiiing fur jjaieiils should also be a row of binding posts fixt secured throuKU nie. was plunged in total darkness along the top of the board, as it is often- Send sketch or model for advice; I assist you market !" ymir invention. Prompt personal service. Booklet and "What the deuce cried "Hen", in alarm, times found convenient as well as necessarj- advice free. and very undignified. "Wouldn't that make to use such an arrangement. ^'*^^- Woodward BIdg. yer mad ?" Jn If ri I Y The transmitting outfit should be equipt • IV«l\.I-iLLI WASHINGTON, D. C From below, on the second floor, there with several inductances, both loose and came in a stentorian voice, a series of in- close coupled, of various dimensions and terrogations, ejaculations and commenta- known values. A rotary, quenched and tions which only served to add terror to series spark gap, together with a large con- jiiiiiifffififiin EVERY INVENTOR an already fluttering heart so while "Ham" denser with plates should have this booh, 'PATENTS AND — removable or other PATENT POSSIBILITIES." It is chock- Tones hunted around in the dark for a means of capacity variation should also be Pat.nl full and practical advice, telling of ideas ten-penny nail P..vm|.iIiI,.., what to invent and where to sell. Write with which to form a 1918 included. If experiments in radiation are for your copy today. IT IS FREE. mode! Jones' Unhlozi'ahle Fuse (Patents to be conducted, it is of course necessary I have requests for patents upon sound Pending) I slunk down two flights of stairs to either construct or purchase reliable III inventions of all kinds. Can you help sup- a 1 plj' the demand? and ran home as fast as I could. hot-wire ammeter. The problem of pro- My servica is individual, prompt and eHrcient (14 years experiencet. Every expedii^nt ia em- viding means for the rapid of Invoiiln'n ployed to secure patents at least possible cost. changing UlllUllUUul' H. S. HILL, 804 McLachlen BIdg., Washington. D.C. connections in the transmitting apparatus AMATEUR AND EXPERIMENTAL is not as necessary as in the case of the RADIO RESEARCH. receiving equipment. Furthermore, the con- NO ATTORNEY H^.luoZ'l nections are not so complicated. A few Send sketch for free report. Books free, Frank (Continued from page 201) heavy switches may be added to the sending Fuller, Washington. D. C. Apparatus Necessary for Research Work. equipment, as they are found to be useful While a well-equipt radio experimental in many cases. Valuable research work Do Business by Mail laboratory is a great asset in research work, can be carried on in the laborator>' by it is by no means an absolute necessity. means of a buzzer transmitter, together It's profitable, with accurate lists of proB- pects. Our catalogue contains vital informa- By means of the ordinary amateur equip- with a wave meter and a dummy or load- tion on Mail Advertising. Also pncesprices and ment, together with a few easily made ac- ing antenna. This is formed of a compact quantitytity on 6.0006,000 nnational mailing liats. 99% cessories, one can do much experimental coil of resistance wire, designed to have guaranteed. Such as: War Material Mfrs, Wealthy Men work of a ver>' useful and penetrating the proper radiation resistance, inductance Cheese Box Mfrs. Axle Crease Mfrs. nature. There are certain research prob- and capacity, and corresponding to a fair Auto Owners etailers lems, of course, that \vould demand elab- size antenna. These are available in the Contractors DniggiBts Fanners, Etc. orate apparatus to work with, but this is market and those interested will receive

te for this valoahle reference book; also j not generally true. information concerning them by writing to 9 and samples of fac-eimile letters The amateur who wishes to do experi- the Editor. Radio Department, enclosing a ur Sales Letter*. . Have us write orT rreviseyou mental work should equip his station with stamped and addrest envelope. Most com- RoM-Gould. 1009T Olive SU a certain amount of auxiliary apparatus. mercial radio transmitters are tested out to- He should first wind several loading coils day on a phantom aerial or load, as they Ross-Gould and inductances of various sizes. These are sometimes termed. See article else- _ n^cailing coils should be labeled as to the number where in this issue on the "load" or dum- S'T. Louis of turns they contain and the wave-length my antenna used by the Federal Telegraph they should respond to (or better still, cal- Company. (.See page 186.) culate or measure the inductance in centi- The suggestions offered above only deal DON'T BE THIN! meters of each coil as explained in the with a general equipment for research Physical Perfection at- series by Secor and Cohen published in the work, and there will, of course, be many tracts men and women, for March and April issues of this journal), instances where the experimenter will have we all admire a well-de- as it is always best to know just what to use his own judgment in building instru- veloped person. Have these, you noticed that it is the one is working with. Aside from ments of special design to carry out his chesty fellcw whogets the several variometers of different sizes ideas. The only suggestion of worth that bestjob? Infactheseems should be constructed, as they are almost can be offered in this way is to work care- to get ahead in every way. I will give you a straight indispensable in work of this nature. It fully and neatly, as results cannot be ex- back, a full chest and an is not necessary to build an elaborate cab- pected from a piece of apparatus that is elastic stride, three of the inet for the variometers, as they can be "thrown" together. Altho it is not neces- best signs of vigor; besides, I guarantee to in- placed inside a square framework, which sary to build elaborate experimental instru- crease your weight 10 to is just as good. On each variometer there ments, they should be neatly and substan- 30 lbs., by building you should be a single-pole switch, connected tially made, as it may be that a poorly con- up scientifically, naturally, without apparatus or across the terminals so the instrument can structed instrument may defeat an impor- drugs, in the privacy of be quickly eliminated from the circuit if tant and valuable experiment that would today for information. your own room. Write desired. At least three receiving trans- otherwise prove successful. Part II will Martin BIdg., Utica, N.Y. EDWARD J. RYAN, formers should also be included in the take up "Suggestions for Research Work."

y'oti benefit by mentioning "The Electrical Experimenter" when writing to advertisers. July, 1917 THE ELECTRICAL EXPERIMENTER 219

Manufarturers are constantly writing me for new ideas protected by OWEN PATENTS. Send fur mv free literature aud read their wants. *'"" ""*"*' uatent books published I Edited by H. GERNSBACK FRFF'"•-*-'• 72- . page Bulde ".Successful Patents:" "Step- pini; Stones" (conlalnine list of hundreds of inven- In this Department we publish such matter as is of interest to inventors tions and wanted; tells the plain truth about prizes reward oilers, etc.), particularly to those who are in doubt as to certain Patent Phases. Regular inquiries and "Patent Promotion" ('tells how to sell your rights ; chief causes of addrest to "Patent Advice" cannot be answered by mail free of charge. failure, etc ) Such inquiries "Patent Burors" Pulilishw otcr -IM lelttr< from those who are publisht for of all If is dt'slre here the benefit readers. the idea thought to be of im- 10 liuj' Oiveu iiatcnla. All sent free upon requctt. Very highest retercnccs. portance, we make it a rule not to divulge details, in order to protect the inventor as I heln my cllenli nil their patents or dlipose of their applications. Advice tree. No oh. far as it is possible to do so. ligation Incurred by writing me. Free manutaclurlng "" "^haroe lor report to Should advice be desired by mail a nominal charge of $1.00 is made for If J,.,.'- as patentability, prac- each ticability, etc. question. Sketches and descriptions must be clear and explicit. Only one side of RICHARD B. OWtN, 164 Owai sheet should be written on. BM?., Wisliii^. D. C. THAT BELL SOFTENER. COVER LIFTING DEVICE. PATENTS (160) The Editor sometime ago in an (163) A. J. Walrath. Detroit, Mich., has Editorial entitled "Inventions Wanted," sent us a description and illustration of a Free Opinion as to Patentability mentioned that there existed a large market clever automatic cover lifting device at- ^^P^ Our Certificate of Patcntabil- for an appliance which would take the dis- tachable to garbage cans or ash cans. Is it ^^^^^^^^ ^^Kl^^^B ity is Evidence of Conception agreealile jar out of the telephone hell. This patentable and practical? ^^^KV^^^^H of and may prove valuable to Our editorial w'as consequently publisht broad- A. A capital idea. Something that ^^^^^^^1 Credit System cnable-s vou to cast by dozens of newspapers and periodi- should appeal to every housekeeper and to file your application for Patent cals. Since then hundreds upon hundreds every janitor. Moreover, the device can be and proceed without delay. Everv case receives personal attention of of letters reached the Editor's desk, nearly manufactured very cheaply, sold and at a one or both members of the firm. all the writers wNsbing to know who would low price. think it extremely practical We Patents we secure advertised st our ex- buy such an invention. and we believe a patent can be obtained pense ID Pi>jmlar Mtefuinxea UagasinM Frankly, we do not know of any, ofif- upon the device. Write loday for Free copy of I04-pa?e book hand. Altho we are certain that if a really "Howlo Obtain a Patent and What to Insenl" good appliance, which fills the bill, is in- INSULATOR. Talberl& Parker, Patent Lawyers, vented, there are a number of electrical 4287 Talbert Bldg., Washington, D.C. manufacturers and telephone manufacturers (164) Harry J. Wright, Jr., North Van- who certainly would want to buy the patent. couver, B. C, Canada, submits an insulator But, like all good things, nothing sells it- for outdoor wiring. This insulator uses self. There was a positive demand for the two nails which are placed in such telephone, long before it was invented, but a man- everybody knows of the long, bitter fight ner that the insulator is not easily pulled that Bell had, trying to introduce his tele- away from its support during storms, or phone. It is the same with almost any in- when sleet settles upon the wire. vention. After you make it, the fight to R. Morgan Elliott S Co. realize on it, begins. If you have something A. A very good and a very cheap in- Pai ENT .Attorneys really good, you will make more money in sulator. There is only one objection and MacMAHtcAL. Electrical the long run by marketing it yourself. 5 Chemical expehts that is that the insulator will crack when 716-724 Another thing : When the Editor sug- woodward building the nails are driven home, due to the fact gested the "Bell softener" he did not have Washington, d. c. some sort of a muffler in mind at all, as that only one point of the nails touch the

most correspondents seem to think. ^luf- top of the insulator. If the top is made at fling the gongs does not solve the problem. an angle, so that the nails will meet the sur- Take the gongs ofT and substitute something face at right angles, a much better insulator that is not a gong. Wooden or similar gongs won't do. Substitute rather something will be the result. We think a patent can giving a musical pleasing note, soft and mel- be obtained on the device. low, which however should not be harsh or abrupt. It is the abruptness of the telephone bell which gets on one's nerves. NOVELTY FAN. (16S) Sidney Brown, Lake Charles, La., MAGAZINE PENCIL. has submitted a design of a certain fan in which are incorporated novelty^ lights. Our (161) Morton Gross of Chicago has advice is asked. submitted to us an idea of a pencil which A. While the idea seems original requires no sharpening. It is made of paper, and —the ONLY kind Wanted ancJ while a patent can but embodies a totally different construc- probably be obtained, we BOUGHT by Manufacturers. think that the resulting flickering of the Send 8c. postage for new book of tion than the present paper pencils on the _ lights will be a serious objection iniless Elxtraordinary Interest to Inventors. market. Our advice is asked. the device is to be used only for R. S. & A. B. LACEY A. An extraordinary good idea, as good advertising purposes, such as window^ display, etc. 63 Barrister Building, Washington, D. C as it is novel. It also seems to us, that it could be manufactured cheaper than the present patent ones. We feel certain that a Write for List of Patent Buyers who good patent can be obtained. PATENTS WANTED' desire to purchase patents and What To Invent with valuable list OSCILLATING DEVICE. of Inventions Wanted. $LOOO,000 i»i prizes offered for inveiitions. Send model or sketch for Free Opinion as to patentability. We have a (162) William Woodward. Wilmettc, Special Department devoted to Electrical Inventions and are in a position to assist 111., submits sketch, an illustration of a novel and advise inventors in this tield in the develo|)mcnt of their inventions. device for making a damped hookup oscil- MODERATE FEES— ASSIST INVENTORS SELL THEIR late. Is the device practical and can it be WE TO PATENTS patented? Write To-Day for our Five Books sent free to any address. (See attached coupon:) A. The scheme looks eminently prom- — — — — ______—FREE COUPON!-^ ______ising on paper, Iiut witliout necessan.- research work, VICTOR J. EVANS & CO., Patent Attorneys we would not be willing to NEW give a final opinion. We advise our corre- YORK OFFICES: 1001-1007 Woolworth Bid?. PHILADELPHIA OFFICES: 1429 Chestnut St. spondent to try it out by building a model. Main Offices: 779 9th Street, N. W., >VASHINGTON, D. C If it works, as described, a valuable patent Gentlemen: Please send me FREE OF CH.ARGE yotir FIVE Books as per offer. will result. have We never seen anything Name Address just like it.

YoH benefit by mentioninff "The Eleelrical F.xl'erimciiler" n/u-ii Hrifiiii; (j ii,/:vr/ii,-r.s. 220 THE ELECTRICAL EXPERIMENTER July, 1917 EXPERIMENTAL CHEMISTRY. (Luiitiiiucd from page 203) EXPERIMENTS Sodium Sulfate [NaHSO,], is formed. FOR EVERY STUDENT CHEMISTS! If two molecules of the salt are taken That's how LLC teach you. electricity in One Year, by actually training and one of Sulfuric acid, a less soluMe salt, you to handle, use and install elec- Normal Sodium Sulfate [XajSOi] is trical instruments and apparatus of formed, during which process a much every kind and style. Our equipment isabsolutely perfect higher temperature is required. and includes instruments and ma- Hydrochloric acid can also be formed by chines so expensive you will hesitate to touch them. Yet we require you the union of its constituent elements, to use them till you know electricity namely, Hydrogen and Chlorin. When the thoroughly. Enter at any time. gases. Hydrogen and Chlorin, are brought Our FREE illustrated Book £ ^H ©ve you fult details. Send for it to-day. together in the dark, no action takes place. DON'T BE HAMPERED If the mixture is put in the simlight, grad- SCHOOL of ENGINEERING ual combination takes place, and if the of MILWAUKEE 322 Stroh Building Mll-WAUKEE. WIS. by LACKof APPARATUS direct sunlight is allowed to fall for an YOU CANNOT SUCCESSFULLY instant, an explosion occurs, indicating the combination of the two gases. This sud- STUDY CHEMISTRY WITHOUT IT. den combination is also effected by the COMPLETE SET. SHOWN ABOVE, FOR application of a flame, by a spark or by WRITE FOR E RULE CO.. Niles. Ulcb. are .\mmonium Chlorid [NTHiCl]. Corrmiercial Hydrochloric acid [Also called Muriatic acid] generally consists of WIRELESS one-third acid to two-thirds water. This BOOKS, RAW MATERIALS if color. liquid pure, should be without While your station is dismantled you can study and from our stocks which we still Sometimes it is of a yellow color, caused build apparatus. Buy maintain complete. either by the presence of dissolved salts of THE ELECTRO-SET CO. NOW KNOWN AS QST contains all the first hand news of iron or organic substances. The chemically THE NEWMAN-STERN CO., Dept. E-14 Wireless and its development In the Great pure [C. P.] should be without color. This Cleveland, O.

War ; How-to-make-it Department Queries ; may be distilled at 110°, when it gives a and Free Exchange Columns. liquid containing 20% Hydrochloric acid, SMALL ENGINES EVERY LIVE AMATEUR NEEDS and corresponds to the formula, HCl + Perfected Gasoline Engines— ^^, 1 and 8H;0. If more Hydrochloric acid is con- THIS LIVE MAGAZINE! 1).^ h.p. —for Farm and Shop use. Price Send $1.50 for a yearly subscription or $.10 for a tained in the liquid, heat will liberate the "$19.50 and up. Also sample copy. You have missed something. gas; if less, water will be liberated upon WASHING MACHINES We sMp en trial. Send for Booklet ind Spectil OMir QST Publishing Company, Inc. Hartford, Conn. the application of heat. SicTerkropp Engine Co., 1401 19th Street Chemical: Racine, Wij. S/

1. Hydrochloric acid possesses a ver>- PORCELAIN strong acid reaction. Into Convert Your Bicycle 2. It is inflammable [a non-com- "THATS OUR BUSINESS" not a Motorcycle bustible gas], and does not support com- Standard and Special Shapes, Regardless Motor fits any wheel. Best, is light or bustion, and not decomposed by most reliable. Best hill climber. More of Difficult How on heating; but its hydrogen may be re- STEFFEVS In use than all othera. A fine motor for running small Dynamos. Lathes and We Illustrate one hard shape we make. placed by metals as Zinc or Sodium, and small shops. Motors only as low as 516 95 A pair of rolls T"-;" long and l^" in its Chlorin Manganese dioxid [MnOi]. SteSe; Mfg. 5025 W. Brown St., PhUa, Pa. diameter with 8 holes on ends and middle. by Cc They must be perfectly straight and we 3. Sodium or Potassium burns vigor- make them so. It's hard but not for us. ously in it on heating, forming chlorids. We can make your difficult; designs also. $40 MOTORCYCLES Send U9 blue print for quotations. 4. It dissociates into its elements at and BirYCLES at cut pricea. 1800°. Singles and twins $25 to $100. New Motorcycle Tires $3. Unioi Electricil Porcelain Works Automobile Tires $3. Beet 5. It dissolves metals, forming most Motorcycle Belts $5. Carbur- etora S6. Spark coils $fi. Secosd* TRENTON, N.J. chlorids. baadBicyclea $5. New Bicycles at Factory Prices. If there are two chlorids of a given Oenloffer. The Price Cutter, Bochestcr. New York

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July. 1917 THE ELECTRICAL EXPERIMENTER 221

liy in mt-t.-il, tlic lower is usually formed acid I H.SO.l small quantities, say three r\(lrorlil(iric acid. Silver |Aj;|, 1-ead or four drops at a time, into the flask, by I Pipe -Threadikc jl'lil, Mereun,- |llj;|. Copper |Cii|, Plat- means of a thistle tube. Do not add too 'TO Sl'f-.EU the w.,rk .-ilid I.Khl.l. th,- inum ll't], Gold |Au|. are not dissolved, much acid at one time. _^ lahor — use the cisy-to-opcralc Dull will or are very sli^litly acted , in small doses as a jiastric stimulant, in hirj;e doses 2. NaCl + 2H.SO, = 2nCI -|- Na.SO. as an emetic; externally in hatlis for the .Sodium Sulfuric Hydrochloric Sodium Chlorid Acid Acid Sulfate relief of rheumatism, and injected in solution, to replace loss of hlood. The equations are more fully explained in 2. It is used for extracting phosphats the preceding methods of preparation. A STITCH IN TIME SAVES NINE from hones. A l.;v stiU-lics thill lan be savftl wlili 3. It is used in dyeing and tissue print- EXPERIMENT NO. 74: "RED DEVIL" TOOLS ing. Loosen the stopper of the flask and very Does your c(»iidcnscT need repalrluK V Do you want to iiifiid your coll? Uo 4. It is used in the manufacture of coal- cautiously try the odor of the fmnes. Do you want to put up that wlriiurf 1' do all these tar colors. not inhale too much, but just enough to will take you a jiffy to Willi till- right tiHil. Made oftem- 5. It is used in preparing other com- give you the characteristic smell. [Notk:— t>crod8ti?i;lanil||[U*iraiIlU!«--v Strong / ^1 hole of bottle No. 1 above the cork and remove the flame from under the flask. You Are s^ below the surface of the water. This is Allow to cool for a few minutes, then un- — called a Safety tube. A third tube just cork the flask, insert a funnel, and cau- passes thru the stopper in bottle No. 1, and tiously pour in two or three test tubes full leads to the second bottle (which does not of water. The flask may then be filled from 0\ contain a cork] and in which the delivery the jet and the contents poured out. If tube is permitted to be under the water. the substance in the flask has caked, be A Wolff Bottle (see Fig. 70) may be careful not to break the glass, but let it used in place of No. 1, and if this form is stand till cool before adding the water. used, one containing three necks is to be Save the liquid in the bottle No. 1 for preferred. the next experiment. It will be noticed in the illustration of EXPERIMENT NO. 75: the app;iratus that rubber connectors (cut To-day it's a battle of wits—and brains win. Pour into a test tube cc. Muscle and brawn don't count so much as they diaKonall.N- — see Fig. 73) are used to con- about 5 of the used to. The great question now is "What do nect the delivery liquid obtained from bottle No. 1 in the tubes of the flask and sec- you know?" It draws the line between failure preceding experiment, and into a second ond bottle. If it is desired, the tubing may and success, between a poor job and a yood one. tidie pour 5 cc. from the open bottle; then be bent in one piece as shown, but it is What do you know? Have you special ability? test each with litmus rnore convenient to use separators, as the paper or solution. Could you "make good "in aftt^jobright now? Determine if the solution is its pieces may then be used in other experi- an acid by For 25 years the International Correspond- ments. action on litmus, as done in some of the ence Schools have been traininif men for bet- experiments already performed. ter work and bigger salaries. They can train Fill the two bottles, 1 and 2, about one- YOU, no matter where you live, what hours To prove what is present apply little youreducalion. quarter full of water. Set the flask on a we must you work, or how Mark find out— it won't ring stand tests for both the fositive and the nega- and mail the coupon and support, on a piece of asbestos obligate you in the least. tive constituents of the compound. or wire gauze. Pour about 5 cc. of water ^ ^ -^ — -^ — TEAR OUTMCRC ^— — -^ — ^— ^ into the flask and add 10 or IS grams of EXPERIMENT NO. 76: mTDWAnONAL CORRESPWOeCE SCNOaS. Boi .Scranlon, Pa. sodium chlorid 5351 [common salt, NaCl|, by Pour about 5 cc. from bottle No. 1 into a Explain fully about your Counc in the subject tnmrked Xt pouring into the flask from a creased small test tube and add two or three pieces nCivil F.nKJnceriOB lADVERTISING nOIIKMISTRT paper. tili^trlfvl ** jSaieamanship Illufttratinn of Zinc. After action has progrest for a Slcum ** Commercial L^w Farm in K " JBookkccpinKI ~ Poultry Have h.uidy a splint, also an evaporating short time, apply a lighted splint to the MinlniE dish containine SlrrhnntrBl ** iSlenoKraphy French three or four drops of month of the tube to determine if a gas Mpfbaiilral llrsftlnr jCivil Service German AmtTioniimi Ilydroxid Arrblrfdiiral llr»(ltnr JRy, Mail Service Italian [NH,C)H|, and a escapes. If we have Hydrochloric acid in AKCHITECTUKE UUTOUUHILI^S ^SPANISH stirring rod or piece of paper. bottle No. 1 it is reasonable to suppose that Make sure that all connections are air- Hydrogen gas will be liberated wdien Zinc Name^ ti«;ht, then pour about 20 cc. of Sulfuric is treated with the liquid. Address-

You benefit by mentioning "The Electrical Experimenter" when urititnj to advertisers. 222 THE ELECTRICAL EXPERIMENTER July. 1917

This is the test for the positive constituent.

EXPERIMEKT NO. 77:

Pour small portions from bottle No. 1 into three tubes. To one add a few drops of Lead Nitrat solution, [Pb[NOs];], to HALTn another a few drops of Silver Nitrat solution, [AgNOsl, to the third a few of Mercurous Nitrat solution [HpNOj]. White precipitates, the chlorids of the metals, Lead, Silver and Mercury, should form upon the mixture of the respective nitrats with Hydrochloric acid.

Soluble Chloeiiis: Soluble chlorids are made by dissolving in Hydrochloric acid, either a metal or some of its salts which are transposed by it.

Insoluble Chlorids : Insoluble chlorids may be made by adding Hydrochloric acid to solutions of the soluble salts of these metals, for example. Lead Nitrat [PblNOs].], Silver Nitrat [AgXOs], Mercurous Nitrat [HgNOa]. There are only three chlorids. Lead Chlorid [PbCl:], Silver Chlorid [AgCl], Mercurous Chlorid [HgCl] insoluble in acidulated water.

Sep.\r.'\tioxs : Suppose we were to mix solutions of Lead Nitrat [PblNOsli], and Copper Nit- rat [CufN'Os];], the lead could be separated from the copper by Hydrochloric acid, for the former would precipitate and the latter remain in solution. On filtering, the lead would remain on the filter as a residue Lead Chlorid [PbCL], and the copper would pass into the filtrat un- changed as Copper Nitrat [CulXOs];], or Copper Chlorid [CuCL], and could be pre- cipitated by Hydrogen Sulfide [H^S], as Copper Sulfide [CuS]. A mixture of Lead, Silver and Mercury salts could, by the same reagent, be separated from other salts in solution. This is exactly what is done in Analysis.

EXPERIMENT NO. 78: Mix in a test tube about 5 cc. of Lead Nitrat solution, and an equal amount of Copper Nitrat solution. From the above explanation, see if you can devise a method of separating the lead from the copper in the solution.

EXPERIMENT NO. 79: Pour about 20 cc. of Sulfuric acid [2 to 1] into a flask supported on an asbestos mat on a ring-stand, and add about 10 grams of Sodium chlorid [Common salt]. Gently rotate the flask so as to mi.x the acid with the chlorid. Close the flask with a two-hole stopper carrying a thistle tube and delivery tube arranged as shown, for the collection of gas by downward displacement in a dry test tube. If necessary heat the flask with a small flame. The contents of the flask will bubble and froth, indicating the pro-

Postage on 8 lbs. is extra. cess of liberating the gas (Fig. 74). contains a goldmine of electrical and Our Bound Volume No. 4 EXPERIMENT NO. 80: scientific information. such value has ever been otTered before No Fill a dish with water and set it on the for so low a price. A marvelous cyclopedia of electricity. A reference table. Take a test tube of gas collected book of authentic information not found in any other book in print. [which is made apparent when the fumes Volume contains twelve numbers, 992 pages, 1,980 complete articles, 1,862 are liberated in the air], close its mouth " tightly the thumb, invert the test tube, illustrations, 266 questions and answers. Size, 12" high; 9" wide; 1 ?4 thick. with and hold its mouth below the surface of A world of electrical information; the entire electrical Progress fur one year; the greatest reference book on current "Wireless"—all at a price LOWER than the unbound the water. Remove the thumb. Notice copies would bring. Mind you. the book is durably bound with attractive green linen heavy how the water acts with the gas. covers. Letters stamped in gold. You will be proud to have it in your library. We have only 400 copies, therefore be sure and order to-day. Shipping weight 8 lbs. Add a sufficient amount for postage. EXPERIMENT NO. 81: Close the mouth of the test tube with the Positively the Greatest Electrical book bargain in the World thumb and remove it from the water. Order today to avoid delay Moisten a piece of litmus paper with the liquid contained in the test tube. The re- EXPERIMENTER PUBLISHING COMPANY, Inc. sult of change of the litmus would show that this effect is typical of the water solu- Book Department 233 Fulton Street, New York, N. Y. tion of acids.

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

EXPERIMENTER 223 July. 1917 THE ELECTRICAL

(^ E«J Scientific Exchange Columns

you have at the present time some things lor which vou have no further use. Do yni wish to exchange them for something, UNDOUBTEDLY columns. for which you have immediate use? There is no surer and quicker way to do this than by advertising your articles in these "5.0U0 interested people The I'l-ry people, the Only people, who could possibly have a use for your things read this journal. More than advertising accepted in (opportunity will see your ad. It is furthermore the cheapest advertising medium for you m the country. Dealers' Exchange foUinins only. .• ... , ,. t -, , l i- The rates arc: Three cents per tvord (name and address to be counted), minimum space 3 lines. Count about / words to the line. than accepted. all orders. No advertisement for less 50c. • Kemillancc must accompany . . ,, .j , l We reserve to ourselves the right to refuse any advertisement which we consider misleading or objectionable. Advertisements for the reach us not later than June 25th. August issue should „ . . „ The Classified Columns of "The Electrical Experimenter^' Brtng Positive Results. Subscribers experiencing trouble in dealing with any advertiser should notify the publisher very promptly. OVER 75,000 PEOPLE READ THIS JOURNAL ^

complete with WANT— 110 A. C. Voltmeter and Ammeter, WAiNTED— 1 K.W. Marconi or United Wire- FOR SALE—AudioTron panel 2" cash or exchange. Have wireless and electrical less Transformer. Harry S. Weber, 1113 N. Wal- new bulb and battery, $7; Mesco spark coil, goods. What do you want? C. H. Rauschenberg, nut St., Can^l Dover, Ohio. $6; Murdock oscillation transformer, $3. Send t-'harleroi. for big list. Want omnigraph. Thomas Kelly, Pa. I'OK S.\LE }4 H.P. gasoline engine in excel- — 1614 S. 54th St., Philadelphia, Pa. or exchange. Alternat- lent condition. Price $15. Howard Pfeifler, 213 WANTED FOR CASH ing current motor H.P. 110 vijlts 60 cycles. Spring Hill, Connersville, Ind. WANTED—Second-hand drafting instruments. yi-Yi Highest prices paid. Send complete description Have 1/12 H.P. variable speed motor. Also want WANTED—Omnigraph; must be in firsl class and will make offer. Deutsch, 2358 Pitkin lathe, Drummond preferred. Carroll Prteegor, All letters answered. Archie E. Banks, we condition. N. Y. Milton, Pa. Ave., Brooklyn, ^ Delniar, Iowa. BARGAINS—3,000 Meter Navy BARGAIN—Smith Premier typewriter for sale. SACRIFICE t.UUU Meter Navy Type Coupler, SACRIFICE: Type Counler, $6.50; Murdock's 2,000 ohm Phones, Cost new $100, will take $25. Little used. Money $6.50; 85 foot Aerial. $5; Vj" Coil, $2.75; ',4 K.W. Bearing, Coil, $1.75: Complete 100 foot Aerial, $5; order or certified check accepted. S. W. Ciap, 50c; Key, 50c. Write for particulars. $3; Yi" Lead-in Insulator, 50c; Knapp Motor $1.25; Key, Covington, Tenn., Route 2. Howard Nance, Troy, N. C. 50c; Gap, 50c; Transformer, $2. Write Bernard EXCHANGE OR SELL 110 volt .Mternating Forest round amplifier or BRAND NEW— De Brown, Troy, N. C. Current \i Horsepower Wcstinghouse Motor. First tubular audion bulb $3.50 each. money- What will you giver Frank V. Golitz, Box 194, order takes them. R. Cuthbert, 375 E. 184th St., mill Patton, Pa. New York. EXCHANC;E—A wireless set, 3,000 M. coupler EXCHANGE for $14—One Smith Premier No. and an AudioTron. Want an F6;3 Kodak. H. RESULTS ! 4 typewriter, excellent condition, used only short I TALK ABOUT | Parker, 212 Park Ave., Syracuse. N. Y. time. Fred Fries, 60 E. Bnnghurst St., German- FOR SALE OR EXCHANGE—Album and over Phila., Pa. lown, 17 PRYER LANE, 500 stamps. Make offer. I want Leyden Jar. WANTED— Stanley Steam Boiler in good work- I | Jesse Burton. Culpeper, Va. Zeiner, 31 East Larchmont Manor, N. Y. H ing order. Will pay cash. Carl FOR S.-\LE—Four cylinder 10 horsepower 2 Pleasant St., Lawrence, Mass. speed Pierce motorcycle, Al conditon, fully WANTED F(JR CASH — Drummond Bros. m The Experimenter Pub. Co. | equipped. magnet,p, rear seat, practically brand Model Makers Precision Lathe. Please be reason- new tires, for quick sale $85. Twelve inch (icn- able. Write. Frank Coffman, Silverton. C>regon. New York City | eral Electric fan, 110 A. C Good shape but old Stevens Favorite 22 cal. rifle $3. SELL AT ONCE—Real Bargains—All model, $3. MUST Winchester 22 Automatic $12. Both in perfect New: Transpacific Receiving Outfit cost $10, B Dear Sir: condition. Blickensderfer typewriter, brand new, price $8; 2,000 ohm Phones (Trans-Atlantic) cost B tools, etc., $10. Complete 100 mile sending and price $4.80; Crystaloi, Type AA, cost $6, price $6, 1 Talk about results! You've § receiving set, first class shape $18. Money orders $4.80; Junior Fixed Condenser 40c; "Electro" or certified checks. Stephen H. Porter, 124 Loading Coil, $2; "Turney" Buzzer, 6Sc; 100 amp. got to give it to the "E. E." m Annetta St., Syracuse. N. Y. 600 volt Switch cost $3.75, price $3; "Electro" Key Siemens-Holske 25c; 9 Ball Antenna Insulators, each, 20c; 8 m to reach the right people. On | SACRIFICE—For cash, $125 Electrose Ball Insulators, each 20c; Ground Clamp, (galvanometer. Extremely sensitive and compact. ft.; 2 Dead be^it. New. Foreign 2,000 ohm polarized 10c; 200 ft. Suspension Rope, 50c per 100 the day after "E. E." came g Aerial Pulleys, each 5c; one 3 volt Nitrogen i relav. Scientific rheostat. Don MacDonald, 215 W. "23rd St., New York City. Battery, 30c; two "Electro" Dry Batteries, each B out I received a reply and b 20c; V2 lb. Friction Tape, 20c; "Electro" Solder- FOR SALE—2,500 mile receiving set, complete ing Outfit, 25c; Fusible Cutouts, 3 fuses, 15c; they have been coming in at J with aerial, fixtures, never been used. $20 for Electrose Lead-in, cost $1.30, price $1; 5 pr. I outfit. John Wells, Ada, Ohio. cleats, 10c; Large Mineral Assortment. porcelain = the rate of one a day. If I FOR SALE— Dynamo, S4.50; l.SOO M. Coupler, 05c; oz. Alloy, 10c; Blue Book, 10c; "Electro' 'i $4.50; Loading Coil. $1: !s inch Spark Coil, $1.25; Thriller and Magneto, 70c; Book "Experimental B ever have anything else that g Storage Cell, $1.50; Erector Motor, 70c; Weeden $1.00; 200 ft. aerial copper Wireless Stations," Motor, 75c; Erector Electrical Set. Postage extra. cable, 50c per 100 ft.; 900 ft. No. 16 Antenium will send 1 I want to sell I my Frank Fletcher. Warner St., Hudson, Mass. copper wire, 30c per 100 ft.; 20 ft. No. 4 copper | new and complete, ground wire, 80c. Purchaser to pay charges on every time. SENDING-RECEIVING H "ad" to you % Printing Presses, Simplex orders less than $5. M\ above brand new. S5.50. Books. Rotary Cash. Fold- Address. Fred ."Mien, Vernon, Alabama. Typewriter, "ModeHt" outfit. Want m Yours truly, B ing Brownie. Other bargains for stamp. Field, FOR S.\LE (")R EXCHANGE— Electrical Thera- South Weymouth, Mass. _^^_ peutic Apparatus new and in good condition; all Clarence de Witt Rogers, Jr. Horsepower two cylinder auto- equipments. Medical remedy for rheumatism, bad a | SELL—Twelve engine complete with carburetor circulation or any stagnetic element. First good mobile gasoline iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiii^ and high tension magneto, $25. Splitdorf and offer takes it. Jolin Ferguson, 113 West 63rd St., with coils. $7.50 Horsepower New York City, home address, 364 West 57th St. Remv magneto's % with boiler, $6. '4 Horse- CHEAP— Smith Motor Wheel, $35. 1 H.P. Vertical Steam Engine D. C. Ammeter $12.50. with boiler, $11. (lENERAL ELECTRIC Redemotor, $8. Both excellent condition Will power Horizontal Steam Engine primary batteries, $8. 60 numbers Middletown. N. Y. Six Edison trade. Enclose stamp Earl Roske. Columbus. Wis . ("laren ce \'aughan. Popular Mechanics, $7.50. "Type BB Crystaloi spark coil, FOR SALE International Correspondence and resonance coil, $10. Want Colts .32 automa- FOR S.\LE OR EXCHANGE—Ford Schools' complete Electric Lighting and Railway 25-20, 32-20 or .22 Winchester $1; telephone transmitter, 50c; telephone magneto, tic pistol and Five leather volumes, finest condition. 75c. Write for list. W'hat have you? Sidney Course. repeating rifles. Coyd MaJTet, Opal, Colorado. Reason for selling, have Collisson. Keokuk. Iowa. Best offer takes them. STOPI LOOK! First $8 gets 4 H.P. motor- more comprehensive course. Paul Mackey, 619 Brief-hand Manual, 35c; $7.50 de- cyclc engine, in fine condition, with tanks, piping, FOR SALE— Shakespeare Ave.. Milton. Pa. tective course, $1.50; $10 finger print course. $1; plug. Write for particulars. Earl Wright, Cole Good 32 caliber Revolver, $4. $5 hypnotism course. $1. Prepaid; back numbers FOR SALE— Camp, Mo. others; elec- .^Iso two Battery Motors, $1 each. Earl Cook, E.E. ; M.E.; A.B.: farm papers and Berliardston, Mass. FOR .S,-\LE—Audion Detector complete with trical and wireless instruments. W. B. Bagley, two bulbs; 'i K.W. Transmitting Set; l^ndamped Stirling City, Cal. FOR SALE— I. C S^ course lii chemistry, coupler; Navy coupler; Phones; Aerial Wire; chemistrv and technology. For Exchange storage 'i K.W. Transformer coil and electrolytic Interrupter; Crystal Detectors. All in good work- batterv, dvnamo, wireless instruments, etc.. for interrupter in fine condition, fi'rst money order for ing order. Louis E. Krieg, Jr., 134 No. School Smith Motor wheel. Leo E. Edmonds. 125 L" St., $6 takes both. Walter Alexander, Dunkerton, St., Gloversville, N. Y. N. E.. Washington. D. C. Iowa. ^_^ Lionel train, 2A WANTED—Burnt-out De Forest Audion bulbs. FOR SALE OR EXCHANGE—A Frank Holton FOR S.-\LE—Receiving outfit. Will pav $1.50 if bulbs are not broken. Harold and 00 Brownies. Stamp for photo. A. L. H. Cornet, with case, costs $50 when new. Every- Schonwald. 443 E. Padon, Blackwell, Okla. Darragh, Beaver, Pa. thing in excellent condition. The first good offer wireless receiv- 1 coil electrolytic in- EXCH.\NGE—Two FOR SALE— Yi" spark and t akes it. Veryl Ebert. Alden. Minn. S.M.E OR condition. Make an offer. ing sets; damped and undamped waves; never terrupter in good LOOK! SACRIFICE!— H" Spark Coil. T. R. Wiley. Piqua, Ohio. STOP! been used. Small transmitting set. M. Guyton, W'heatstone's Bridge. $3; Large Voltam- $1.25; Cotton Plant, Miss. F(^R S.\LE— Electrical and wireless apparatus, meter. $3; all rest E. I. Co. goods; $1 Key. 60c; 5.\.\ Receiving Transform- a small mechanical ilrawing set, a ten mile Pedom- Condenser. 75c; 3. 15 Ampere FOR S.\LE—Duck's Fixed Variable Turney Buz- eter. Send stamp for list of other apparatus. 20c each; Ammeter, 40c: er, $15: Tvpe "O" Crystaloi. $3,10: D.P.D.T. Switches, High grade 4x5 Francis T. Crump. Jr.. Columbus. Ind. Hustler Motor, 40c: Receivers, 1000 ohm D.P., zer. "Oc. All new. never used. Folding Camera, uses films or plates, automatic FOR SALE OR EXCHANGE—4 HP. motor- $1; 2, 75 ohm DP., $1; 2, 75 ohm S.P., 60c. 1034 8 speed shutter, carrving case. etc.. $15. J. Frank cycle engine $15 for bicycle, rifle or what? M. Satisfaction guaranteed. C. Krummenacker, J. Key. Buena Vista. V'a. Liese. 511 S. Morgan St.. Chicago, 111. 7.1 St., Brooklyn, N. Y. adierliscrs. You benefit by mentioning "The Electrical Experimenter" when uriting to ... : . —

1917 224 THE ELECTRICAL EXPERIMENTER July. =^ Opportunity Exchange anywhere else in the country. Most„ good things in VOL" will probably find more opportunities and real bargains in these columns than will be the real loser if you don t take the 1 lite are hard to find and worth going after—these little ads illustrate that point; you alone to these columns. time scan through j i- insertion. words per line. Advertisements in this section 4c. a word for each Count / • j unless piaccd byk an,„ accredited,...-„^;t,H Name and address must be included at the aV.ove rate. Cash should accompany all classified advertisements advertising agency. Objectionable or mislea^ling advertisements not Ten per cent, discount for 6 issues, 20 per cent, discount for 12 issues from above rate accepted. i l t -i- Advertisements for the August issue should reach uf- not later than June 2d. OiTR 75,000 PEOPLE READ THIS JOLRNAL EXPERIMENTER PUBLISHING CO., INC.. 233 Fulton Street, New Vcr,:. \ Y feg ^ CHEMIC.M,S PATEXTS—Without advance attorney's fees. AERONAUTICS Xot due until patent allowed. Send sketch for free report. Books free. Frank Fuller. Wash- growing chemical plants. ACE. .Vmerica's only illustrated CHEMICALS FREE for ington^ AERIAL introduce our chemicals and apparatus to Ex- weekly, presents the latest developments in aero- To perimenters, we will send free, the necessary Manufacturers are writing nautics throughout the world. Up to the minute IDEAS WAXTED— chemicals to grow trees, grass, etc. Send 10c for patents procured through me. Four books with technical intormation concerning aero-engines, (refunded on first order) for postage and list of inventions wanted sent free. I aeroplanes, accessories and patents. Complete coin hundreds Zenith Chemical Laboratories, 307 West vou market vour invention. Advice Free. model news and instruction. Trial subscription catalog. help bample Second St.. Duluth, Minn. R. B. Owen. 130 Owen Bldg., Washington, D. C. six months, twentv-six issues. One Dollar copy free. Aerial Age, 2S0 Madison Ave., New R. Morgan Elliott & Co.. Patent York City. New York HELP W.\NTED PATEXTS— Attorneys. Mechanical, Electrical and Chemical Experts^ 716-724 Woodward Bldg., Washington, Men -Women. 18 BOOKS WAR MEAN'S THOUSAXDS D. C. or over, wanted by Government for excellent TO GET BETTER PICTURES; Read the clerical positions, SlOO month. Steady work. Short Amateur Photographer's Weekly; dlustrated; hours. Life appointment- Common education JOHN M. McLACHLEX, attorney-at-law weekly prize competitions; print criticisms; many sufficient. Write immediately for free list of Patent causes. Inion Trust Bldg., Washington, unique features: SI. 50 per year; three months trial positions now obtainable. Franklin Institute. D. C. subscription, 25c. Abel Publishing Company. 401 Dept. T>27. Rochester, X. Y. Caxton Bldg., Cleveland. Ohio^ PHOXOGRAPHS BOOKS— Scientific and wireless supplied. Let MISCELLAXEOUS us know what vou want and we will quote you. BUILD YOUR OWX PHOXOGRAPH or Experimenter Pub. Co., 233 Fulton St., New ^ ork BOYS: LOOK:—Send one dime for the Letter manufacture them for profit. Drawings, instruc- Citv^ ^_^ '"H"' Puzzle, the hardest on the market to solve. tions, etc.. Twenty-five Cents. Satisfaction guar- The greatest Circular free. Associated Phonograph A BINDER for THE ELECTRICAL EXPERI- Or the 'Phantom Trick Cards." anteed. invented. Chas. H. Derr, 306 N. Dept. E, CincJnnati- MENTER will preserve your copies for all time. card trick ever Co., Price 50c. Postage on 3 lbs. is extra. Send for 9th St., Allentown, Pa. one todav. Experimenter Pub. Co., 233 Fulton PHOTOGRAPHY Initials for monograming St., NewY'ork City. DECALCOMAXIE automobiles, etc. Wholesale price list and samples back numbers of THE ELEC- DO YOU W.^NT free. A set of Old English letters and material FILMS DEVELOPED FREE. Prints any size, Send for bound TRIC.\L EXPERIMENTER? for quickly applying Sl.OO postpaid.^ Globe Deca!- 30c dozen. A. Hill, 6112 Woodland Ave., Cleve- volume No. 3 containing issues from May, 1915 comanie Co., Mfgs., Jersey City, X. J. land, Ohio. to April, 1916. Price, $1-25. Postage on 7 lbs. Experimenter Pub. Co., 233 Fulton St., is extra. FORMULAS—We will send you the Formula MOVIXG PICTURE FILM lOc. 48 real mov- Y'ork City. long. stamps or coin. New for anything you want to know for 1 Oc < coin ) ing pictures three feet 10c O. Box 257. Lewiston, Maine. \S'E HAX'E a limited number of beautiful art Xational E.xchange, 1314 Park Ave., Xew York. P. pictures of the following famous electrical men on Postage. 2c. hand. Nikola Tesia, Thomas A. Edison. Guglielmo STAMPS— 75, all different, free. Toledo, Ohio. WIRELESS Marconi. Charles P. Steinmetz. and Reginald A. Mention paper. Quaker Stamp Co., Fessendcn. These make a handsome decoration for any laboratory or workshop and should be prom- SEXD 4c for our new. complete catalog of Books. inently displayed. Price for five, prepaid, 25c. Electrical, Mechanical and Automobile We Experimenter Pub. Co., 233 Fulton St. New York also carry a complete line of Electrical and transformers, spot- City. Automobile supplies, flashlights, Prices lower. Get your copy today. 131 LAKE AVE.. lights and etc. OLD E.E. B.\CK NUMBERS—We have some M It will pav to investigate. Xorth western Ohio per \'. valuable old E.E. back numbers on hand as ^ . Lancaster, N. Specialty Co.. Box 493, Central Sta. Toledo, Ohio. list below. m Feb. 22, 1917. 1915 March . .price each $.20 8" " " " AMATEUR BEXCH LATHE—Austin make. April . Jan. . .price each $.25 between centers, 3 speed pulley, very strong, neat '* " " Gentlemen Feb. .. May .. . H and efficient. Price only S3, worth double. '• " " in Limited supply on hand. Louis E. Schwab, 3708 March June . H I wish to tell }-ou that ray ad. tt Cleveland, Ohio. *' «( Brooklyn Ave., . April . July .. S the E. E. was a great success, and tl n August . " May .. e.xceeded all expectations. I had re- Help your *' tt »i H KILL TWO BIRDS with one stone. June Sept. . country AXD yourself. The first S50 profits we " *' " plies before I had received a copy of July .. Oct. .. H make on this advertisement buys Liberty Bond. *• .. «( Improved Electron Relays are BEST and have 800 August Nor. .. . H the issue myself. This goes to show " hour guarantee, S5 prepaid. PREPARE FOR .. . " Sept. . Dec. B that ever>- issue is looked for with peace: Somerville Radio Laboratory, 102 Heath

Oct. . 1917 Somerville, Mass. great interest, and the w ide field voiir St., *• " M . , .15 Xov. . Jan. .. " « .( paper covers. I certainly will recom- Dec. .. Feb. .. . XOW THAT AMATEUR WIRELESS is ta- " " " booed use your transformer, etc.. for high fre- 1916 March . mend it to the amateurs that have H quency experiments. I have the apparatus you . •* " " . ^0 April . . Jan. H something to trade or sell. want or can build it. C. H. Rauschenberg, Ex. " ** " Feb. .. May .. = Yours resfcctfully, E. Charleroi, Pa. We can fill orders at once upon receipt of your remittance and if you have not these numbers al- G. \V. Bradfopo. I will furnish a standard ready now is your chance to get them as they prob- HORSEPOWER? counter and directions for finding the ably will be snapped up rery quickly. Experi- revolution horsepower of any motor for 40c, counter alone menter Publishing Co., 233 Fulton St., New York worth 75c. Louis E. Schwab, 3708 Brooklyn, City. ^ Cleveland, Ohio. FIRE SALE OF SLIGHTLY DAMAGED p" rn-ni "I'lTminiiniiiLi "?raiiiiiiffi FIRE SALE—We have a great many slightly BOr*KS. Due to fire in our stock rooms, a great electrical apparatus and supplies on hand many oi our books were water stained but not other- damaged extraordinarily low prices wise damaged. Rather than dispose of them to which we are selling at while they last. These goods were damaged in our dealers we prefer to give our readers the benefit. PATENT ATTORNEYS recent fi're and embraces such ^oods as telephone Look at this list! Our Celebrated Wireless Course, telephone cords, printing presses, telim- 160 pages. 400 illustrations; List of Radio Stations receivers, detectors, tuning coils, rotary condensers, of the World; Experimental Electricity Course, PATEXTS OX EASY PAYMEXTS. Send phones, jars, porcelain tube insulators, strap keys, U)0 pages, 350 illustrations; How to Make Wireless model or sketch for Free Search and Certified leyden Inter-City transmitting outfits, Sending Instruments. These four books for SI. 50 Registration of Your Invention for Your Protec- Gernsback relays. for list and prices today. Wonder- prepaid. Regular selling price of these four books tion. Free Book Tells What to Invent and How- etc., etc. Send Payments. C. C. ful bargains such as will not readily occur again is $2.75. We guarantee you will be satisfied. Ex- to Obtain a Patent on Easy time to come. Electro Importing Co., perimenter Pub. Co.. 2i3 Fulton St., New York Hines & Co., 593 Loan & Trust Bldg., Wash- for a long St.. Xew York City. City. ington, D. C. 231 Fulton

You benefit by vientionittg "The Electrical Experimenter" when writing to advertisers. — - ~

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

Hawkins Electrical Guides Will Show You How These books are the standard works on Elec- trical Science. " They are a complete and up-to-date course For the man not Kettintf a in Electrical college training- and even in Engineering, presenting the information in a wiiy you -sl. that case. I can sincerely say I can use it. Only 00 per volume and owners of the set do not believe there is a bettnd the an.swers Elbbidgb Ball to them— in plain, tion." F. practical, ever.vdav langu;age. complete, concise, authentic Buckland, Conn. to the and point. Over 3200 p: iges and more than 4,000 illustrations 10 NUMBERS IN ALL

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YOUR Shipped to You FREE J^.FREE PON H Send no money. Examine the books first. Decide for yourself that they ^^ Theo. Audel & Co. are library of Electricity published and that you can- ^^ the most complete ever ^^72 Fifth Ave, N. Y. not afford to without them. book is in itself, but the complete set is .-î ^^ be Every complete ^^^ I'Kase liii im for ^^ the best bargain. The last volumes are just coming off the press. F It K K examination ^^ H a \v k i n s Kleclrical this offer now J^r Ouldes (Prlce ^^ p0d# P?l\f^ciymt?lll»rtir^tl4g Accept unusual — $1.00 each> ^^«»»y today. Each page-every illus- J^ Tilx'ûmberrit'sllViffactory tration will convince you of the big value ^^^ I a^rec to send you ji.oo each A FEW OF THE SUBJECTS we are offering. See the books first, month until paid. Ma(tTH-ti-m— Inrtin-tion— Kxporinicnli — Itynamos ^^ — ^!ll•lt^lc M.icluni-ry Ms— Electi i- them vou can make settlement at -.. c I Instrument Trstint' — Practical Manajremrnt ^^T Signature of Dvn.imoH ariit Motors— Distribution SyHtems— only $1.00 monthly until paid for. ^^ Wirintf— Wiriiur I)iaKr:»mB—Sitrn Flnshcrfi—Stor- aK« Hatteriffi—l*rinfii)lf3 of Alt«TnatinK Currents ami Alternators—AUematmir Currt-'nt Motorti— ^^^ Occupation Trans f ormern—Converters— Rfctifu-rs—Alternat- int: ('urront SystemH— ('irruit IlrcoktrK— Mt-aHur- Theo.Audel&Go.^ in»f InMtrumcnts—Switch Hoardn- WirinR*- Powlt Business Address. SUtiona- lnstalli^K-TÎonhoê-Tel.^râph- 72 Fifth Ave. Wi^^lt•sR— liclls— LurhtinK— fCiilways. Also many 'O'l'-m I*r:u!tical Api.licationB of Electricity and NEW YORK <.'aay Kcfcrtncc Index of tlio lU numbers. Residence .

Reference July E.E.

i'ou benefit by mentioning "The Electrical Experimenter" ivhen writing lu advertisers. nn €€ Think Beyond ^ur Job! Charles Schwab, in "There is not a man in power at the Bethlehem Steel Works today," says M. leaders rose the American Magazine, "who did not begin at the bottom and work his way up. These from the ranks. They won out by using their normal brains to think beyond their manifest daily duty.

"Eight years ago Eugene Grace was switching engines. His ability to out-think his job, coupled with than a his steding integrity, lifted him to the presidency of our corporation. Last year he earned more million dollars. "Jiipmie Ward, one of our vice-presidents, used to be a stenographer. But he kept doing things out one. he has of his regular line of duty. He was thinking beyond his job, so I gave him a better And gone up and up. The fifteen men in charge of the plants were selected, not because of some startling stroke of genius, but because day in and day out, they were thinking beyond their jobs."

• TEAR OLT HERE What about you? Are you satisfied just to hang INTERNATIONAL CORRESPONDENCE SCHOOLS on where you are? If so, rest assured that's as far as get. But if you want to be somebody, to Box 5350. SCRANTON. PA. you'll ever the climb to a position of responsibility, get ready for it. Explain, without obligating me, how I can qualify for the position, or in are doing noiv better than the men subject, before wh'ich I mark X. Do what you the job ahead. can do ilECTRUAL ENGlNEElt QBridge Engineer TRAEFK' MA.NAtiEMENT beside you and train for You Draftsman Cartoonist QEIectriciao Q Structural it— in spare time—through the International Corre- Electric Wiring D Structural Engineer ILLCSTRATOR D Schools. D Electric Lighting QMunicipal Eoeineer Perspective Drawing spondence Electric Car Running D AU( IIITEtT Carpet Designer Heavy Electric Traction Architectural Draftsman Wallpaper Designer For 25 years men of ambition with I.C.S. help Drafism; and Builder Bookcover Designer Electrical DContracior the stepping-stones to Electric Muchine Designer QBullding Foreman Monument Designer have been making spare hours School Subjecu Telegraph Engineer Lumberman Common successful careers. Last year more than 5,000 MECHAMIAL LM. INFER Concrete Builder High School Subjects Mechanical Dradiman PLl BRER A STEAM FITTER QMathematic* reported that their studies had won for them advance- Machine Designer ment and increased salaries. In the Bethlehem Steel Machine Shop Practice DPIumbiDg Inspector Boilermaker or Designer Foreman Plumber QConon Manu/ncturinc Works alone over 100 men right now are putting D QWooleo Manufacturine n Patternmaker DBCSl^ESS (Compute) their spare time on I.C.S. courses and thinking Toolmaker O Bookkeeper DCIIEMU'AL ENtilNtEU Foundry Work DStenographer & Typist Analytical Chemist ahead, getting ready for the better positions that Blacksmith D Higher Accouniinc Onl>Ftl>KLn.i.\UR£NGI.\EEK them. And over 130,000 others in Sheet-Meial Worker DCertified Public AccouotaotQ Coal Mining surely await AlTOMOUILtS DRailway Accountant O Metal Mining offices, shops, stores, mines, and mills, and on rail- Automohile Repairing Commercial Law U MetallurgUt or Prospector D all America are preparing in the I.C.S. way STEAM EN(;L\EEIt Q Good English Q Aaaayer roads over Steam-Electric Engineer nSAI.ESJIANSIlIP ONATIUATION OSPAMSU to take the next step upward. Stationao' Fireman nADVEKTISlNt; BAS D Motor Boat Kuna'p G French Atarine Enginerr Trimmer AtiKHl LTIKK DGermao D Window D Join them! All you need is just ordinary brains, Refrieeration Engineer D Show-card Writer D Fruit (;rowing Dltallan Gas Engineer D Outdoor Sign Painter D Vegetable Growing the will to do, and the firm resolve to think ahead of E.NGI.NKKU QflVIL MKKVKE DLive Stock and Dairying CIVIL are ready to make Surveying and Mapping DRailway Mail Clerk D Poultry Raiser the job you now hold. The I.C.S. R. Reconstructing DMail Carrier Poultry Breeder the rest easy. hlame_ Make your start NOW. A^ark and Occupation_ _Cmployer- mail this coupon.

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