Popular Science Monthly 1915-12: Vol 87 Iss 6

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Lew COLibe

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The Ceaseless Search that makes Homes Brighter At our Research Laboratories in Schen- ectady scores of scientists are steadily at work in the far-reaching lamp investi- gations that MAZDA Service carries on. Day after day the search goes on, studying, testing, experimenting—and little by little your home grows brighter and your light bills lighter. For as each new idea.in lighting, each new material and new method of con- struction is tested and approved, MAZDA Service transmits it immedi- ately to our manufacturing centers at Cleveland and Harrison, and to the other manufacturers entitled to receive it. And thus the results of MAZDA Service come quickly to your home. But the important thing to remember is that MAZDA, no matter whether you see it today, tomorrow, or_years hence, is always the mark of this scien- tific Service to lamp manufacturers— alwaysasign to youthat the lamps so marked represent for the time being the sum of all that science knows of incandescent lighting. GENERAL ELECTRIC COMPANY

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Wanted: Opinions The Editor of the Porputar Science Montuuy feels that this magazine is not his but yours. You can help him by telling him what you think of each number as it reaches you. Go over the magazine carefully. Note the things that you like, that appeal to you, that suggest ideas to you, and that help you. Against them place the things that you don’t like. There are the departments, for instance. If you are a wireless operator—amateur or professional—tell the Editor what you think of the radio articles. If you are a handy man who likes to work with tools and make useful things, let the Editor have your opinion of the “Practical Workers’ and “Home Craftsman” departments. If the magazine neglects a subject in which you are interested, say so. If you have ideas for articles, send them in; also photographs. You will be paid for them if they can be used. We want to make the Popunar ScrENCE Montuty better and better with each num- ber. You can help us by writing freely to The Editor of the Porunar ScreNcE MonrTHu ty, 239 Fourth Avenue, New York.

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WHAT A SLIDE MEANS AT PANAMA cS age i a ma m, P 5 Kn Ne cle SP Sih eee @) Laccrmeu o Cuuermoud, N. X. It will take months before the Panama Canal is opened to traffic again, as anyone will believe who contemplates this picture. Not only is the fairway clogged by slides, but also by mud, which is forced up from the bottom because of the pressure of the mountainous masses on either side of the Canal 706

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POPULAR SCIENCE MONTHLY AND WORLD'S ADVANCE Vol. 87. December, 1915 No.. o>) Why the Slides By J. F. HILE the Panama Canal is by no means the longest in the world— the Suez Canal is twice as long—still the problems met and solved in its construc- tion make it one of the truly greatest engineering undertakings of the world. And yet, the conquest of the natural con- ditions is not quite complete. The slides in Culebra Cut are not only a continual menace to the continuity of operation, but, as the present situation proves, they may easily interrupt traffic for months. The canal pierces the continental ridge, at Panama only a few hundred feet in height and nine or ten miles in width. A V-shaped cut was made through this ridge and the canal located at the bot- tom of the V. It will be seen at once that there must be high slopes to either side. The slides occur because a mass on a slope loses its frictional grip on the underlying material, and slips — not Slide at Panama Springer necessarily with rapidity—on and down under the influence of gravitation. But “on and down” bring it at last into the canal itself. It may confidently be ex- pected that in the course of time every- thing will have slipped and slid that is going to slip and slide; so that eventually the trouble will cure itself. No doubt the engineers put some dependance upon this consideration. If the slides could be counted upon to be moderate in their in- dividual attempts and to allow proper in- tervals between, then we might be con- tent to await a condition of final equilib- rium. But the canal was built for stra- tegic and commercial purposes, neither of which can wait on so slow a process. And so General. Goethals has resumed his control. The Panama Canal, unlike that of Suez, is not a sea-level waterway. The main portion of the canal, from Gatun SN LIMET oF STEAM PRESENT : SURFACE The canal was cut through a mountain in the form of a “V.” Parts of the “V” have been steadily slipping down because they were located upon an underlying toboggan surface of firmer material, so it is thought. The illustration shows how the “V” has gradually 707 widened since the first cut was made

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108 Locks in the north to Pedro Miguel Lock in the south, has its normal surface eighty-five feet above the sea level on the Atlantic side. This means that the bottom is some eighty-five feet higher than would be the case if the water simply flowed through from ocean to ocean. The canal was elevated to se- cure the advantage of not having to cut the V down to the low level necessary for a_ sea-level canal. Carrying the point of the V down to a level eighty or eighty-five feet lower would mean vast additional excavation on the sides of the V. So the canal was constructed on a high level. The most notable of the slides is known as the Cucaracha. It is at least thirty years old, and began its activities long before the Americans took charge, during a long period of inactivity extending from 1889 to 1905, a period when but little was done in the way of excavation. The motion is frequently slow, amounting to no more than a few inches per hour. It probably moves more or less in all seasons. But Cucaracha is by no means the only slide. In one year as many as thirteen slides were in movement in the region of Culebra Cut. Slides occur at all seasons of the year. The precise cause of a slide does not seem to be known with cer- tainty. It is probable that some slides . may be safely attributed to the slow to- bogganing of soft surface material on hard, underlying rock sloping toward the canal. The cutting away of material on the lower edge may easily precipitate a general movement of the material above simply because a support has been re- moved. The slides have other effects besides that of moving down into the canal. One night in March, 1913, a break on the eastern canal bank, opposite the town of Culebra, resumed an activity which began some weeks before. The exca- vated surface at the bottom of the canal near the center was lifted up for a dis- tance of one thousand feet. This up- heaval had a maximum elevation of as much as thirty feet. This phenomenon is due, no doubt, to a kind of see-saw action. The movement of material down towards the canal increased the weight at ihis point, which reacted against soft POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE material underlying it and the canal bot- tom, so that the soft material was pressed down at one point, pushed up at another, thus forming a ridge in the bottom of the canal. At any rate, this seems a reason- able explanation of this and similar oc- currences. The same slide repeatedly produced the phenomenon of pushing up the bottom of the canal. There are two great slides near Culebra, one on the western bank and the other on the eastern bank. These two move toward each other and produce a double effect. They affect a length of canal channel amounting to more than half a mile. Both are north of the two — ridges known as Gold Hill and Contrac- tor’s Hill, which face each other across the canal. The two slides comprise an enormous total of slipping material. The estimate runs as high as nine million cubic yards. The limits of the move- ment are located at considerable dis- tances back from the line of the canal. On the eastern side the break goes back to a line one thousand five hundred feet distant from the canal axis. On the western side the break is nearly as far back. The movements extend far up the slopes—in the one case to a level two hundred and sixty-five feet above the canal surface and in the other to a level five hundred feet above. The material is being taken away at the bottom. Cucaracha Slide may be counted on to be active at almost any time slides should be working. If the canal had been con- structed as a sea-level waterway these slides would probably have been still more active than they now are, because of the greater opportunities with an added eighty-five feet of depth to Culebra Cut. It seems doubtful whether the move- ments of earth and rock at Panama are in general due to the steepness of the slopes to either side of the canal. Such an influence may indeed play its part. The controlling cause appears rather to be tilted underlying rock. The mass on the rock moves down however it may be piled up. It seems rather curious, though, that the canal should have been located just where two such tilted rock surfaces intersect each other—that is, just above the bottom of a hidden rock valley.

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i spex samba Ee, ‘ Drying Rain-Spattered Windshields by Electric Heat A new device for automobilists has been put upon the market, which when it is raining, dries a portion of the wind- shield, so that the driver can get a clear view ahead, even when the rain descends with some force. A metal frame fits closely to the shield and electrically dries the spot inside the oval frame. The drying process is ac- complished by a coil of insulated wire resting on the glass and connected with The metal frame fits closely to the shield and electrically dries the glass the batteries. These wires supply enough heat to dry the glass within the frame. The frame is equipped with two hooks, two springs, and a cord and plug to con- nect with the batteries. To attach the device, one hook is placed over the lower edge and one over the top edge, and a spring inserted in each hook, which sus- pends the frame between the springs. When the plug is inserted in the perman- ent socket in the dashboard, the glass within the oval clears very quickly. Protecting Letters Against Mail Box Thieves Owing to the various war loans, funds and charities which are being raised in England, the large amount of money passing through the mails has proved a great temptation to petty thieves. Great numbers of valuable envelopes have been removed from letter boxes with the aid of a piece of string and a bit of Ameri- can chewing gum. An ingenious inventor has recently de- vised a simple and inexpensive protection against such thievery. Two rows of POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ~~ 1709 wire, each having a sharpened hook at its end, are placed in a spring inside the opening of the box. One of these rows is held up by the springs, and the other is sprung downwards. A letter may be easily passed through the slot, as the springs allow the wires to disengage, and permit the unhindered passage of the envelope. When a thief attempts to extract a let- ter from the box, the sharp hooks catch the paper and prevent its removal. It is said that the inventor has fitted thousands of these devices to the mail boxes of banks and other financial and business houses in London. The average increase in retail prices of food products in the twenty-five lead- ing towns and cities in New Zealand for the year ending July thirty-first, 1915, was twelve per cent. The greatest ad- vance was in the prices of groceries. HTT | | | Pit Ty] “4444-14 -a@\ Two rows of hooked wires permit of easy insertion of letters, but defy the letter-box thief who, as shown in the upper picture, tries to steal letters with a piece of chewing- gum on the end of a string

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710 POPULAR SCIENCE A Cuban mountain-going vehicle remarkable for its comfortable riding Curious Vehicles Used in Cuba Two old vehicles which are now rap- idly disappearing from the streets of Cuba are the volanta and the three- wheeled, glass-encased peddler’s push cart. Prior to 1898, when Cuba was a col- ony of Spain, these vehicles were to be seen everywhere. The volanta, with its long shafts, its team of horses and rider, was admirably adapted for the mountain- ous regions, and was a general means of rapid transportation. Nowadays, it is sel- dom to be seen—except in the moun- tains, where it is still too well suited to the conditions to have entirely disap- peared. Sap am am BES he : Be sant The Cuban peddler is giving up this ancient vehicle for carts with better display space The peddler’s cart shown was also familiar. Like the volanta it is passing fast. A few. are to be seen in the poorer quarters of cities, but in a few years will be seen no more. MONTHLY AND WORLD’S ADVANCE Seeing the Panama Canal in a Chair By means of forty-eight phonographs equipped with a number of duplex tele phone receivers, visitors to the Panama Canal exhibit at the Panama-Pacific Ex- position listen to a lecture while they are being carried around the exhibit in observation cars. The cars, in which the sightseers sit and are drawn around the perimeter of the huge oval model of the Canal, are each equipped with a set of these phonograph receivers, arranged to de- liver the series of fifteen lectures which are given on each trip. The receivers are conveniently hung on hooks on the Franson to lectures on the Panama Canal as they travel in observation cars past a re- production of the Canal backs of the chairs, and by fitting them over his ears, the visitor may hear a most comprehensive description of the Canal and its operation. Heat Improves Concrete At the present time, when concrete is a common and widely used building ma- terial, it is most important to know what effect temperature has upon its strength. The ngineering Experiment Station of the University of Illinois has made ex- haustive tests upon concrete at different temperatures and has made several im- portant deductions. Concrete which is maintained at a temperature of sixty to seventy degrees Fahrenheit will, at the age cf one week, have practically double the streneth of the same material which has been kept at a temperature of thirty-two to forty degrees. Uniform temperature gave steady increase in strength with age,

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Completing the great Hell Gate Arch. Parts of the material which will eventually be built into the bridge itself are holding the two arch members temporarily in place Building the Largest Single Span in the World | By C. E. Drayer HE erection of an arch by the cantilever method makes use of the same principles as the swimmer does when he fastens down his spring- board.. Backstays must be of suf- ficient strength and anchorage to hold the arch up as it grows out from its abutments. To lay out in the field a huge struc- ture nearly a fifth of a mile long, like the Hell Gate arch, just completed in New York City, with nothing more’ stable than water between the abutments, yet with such accuracy that every rivet will fit exactly according to a predetermined plan, is a task of the utmost nicety. In the Hell Gate arch the abutments were located by the “triangulation” method. A base line several hundred feet long located conveniently on the shore, was very exactly measured, correction being made for the stretch, sag and tempera- ture of the tape. From the opposite ends of the base line, which telescopes of the transits was the point to be located. Assistants marked the point of intersection very carefully. Again and again the angles were read until all possible error was eliminated. If at all possible, in work of this char- acter, the distance from abutment to abutment is checked by direct measure- ment with a steel tape before the erec- tion of the structural work is started. On the Hell Gate arch a specially con- structed steel tape one thousand and fifty feet long was used. This tape was three- thirty-seconds inches wide and one- thirty-second inch thick and its end graduations had been carefully checked at standard pull with the tape supported from end to end. When the tape was supported at each end only, a pull of seventy-one pounds was required to cor- rect for sag. This pull was applied by a spring balance and turn buckle rod at one end of the tape. When correction had been made for tempera- ture, it was found that “UPPER CHORD had a definite relation rp---—z to the points to be lo- } Ae cated, known angles. : were turned with tran- sits so that the point of intersection of the lines of sight through the A general elevation of the Hell Gate bridge, showing how the arch was temporarily supported the distance obtained by w»' the tape exactly checked that obtained by triangu- lation. But all this careful work in the field pre- 711

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712 supposes just as careful work in the shop. Assembly of portions of the arch at the shop was required to make the joints true and assure an accurate and easy fit in field erection. So several panels of the arch were laid. horizontally in the shop and connection holes carefully marked and drilled. Usually the entire structure is laid out at one time in shop assembly, but the tremendous size of the Hell Gate arch made that plan impracticable. As the arch unfolds, panel after panel, additional weight is added, which causes deformation in the steel already in place. This must be computed for each member and an allowance made in the shop for the stretch in the upper chord and short- ening in the lower chord. Each member must be made a little shorter or a little longer, as the case may be, to neutralize the deformation it undergoes in erec- tion. Naturally the correction made in each individual. member is small, the large correction of perhaps a foot at the crown being due to the cumulative effect of the individual corrections. The junctioning at the crown offered no particular difficulty in this great arch, as the halves meet in a simple butt joint, afterwards riveted into a solid connec- tion. In the Hell Gate arch, the first attach- ment of the backstay was at the end of | the upper chord (A on diagram). When the overhang became too great, a second attachment was made (B) which was strong enough to carry the arch and the two great traveling cranes used to hoist the steel to position until junction was made at the crown. Temperature plays an important part % POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE . cooled and expands when heated, and the in bridge building. Steel contracts when engineer must make special provision for these temperature changes in. the struc- ture he designs. In the ordinary truss, expansion is taken care of by roller bear- ings at one end. For a span of four hundred feet the change in length due to temperature would amount to nearly three inches from zero to ninety degrees Fahrenheit. But in a bridge like the new Hell Gate arch, whose ends are firmly fastened to massive concrete abutments, this expan- sion must be cared for in a different way. The arch rises and falls like a huge thermometer, so that over the range of change in temperature experienced by New York during a year there will be a change in the elevation of the crown of the arch of nearly a foot. A Binder on Skids Unusual weather conditions in the western states presented many difficult problems during the harvest season. Flooded wheat fields gave ample oppor- tunity for the demonstration of inventive ability on the part of the farmers. Perhaps the most interesting device used by a farmer to save his wheat crop was that of the Kansas farmer who made a pair of skids for his binder. The muddy, soggy condition of the field made it seem impossible to use the heavy machine. In some parts of the field water was standing, but this farmer was able to save every bit of his wheat crop, as the skids carried the binder through the muddy field without trouble. This Kansas farmer saved his wheat crop by running his binder on skids over the water- soaked fields

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The Fatal Hum of the Submarine By William Dubilier The author of this article is an American electrical engineer, who went to Europe, at the invitation of one of the Allies, to devise a system of har- bor defense against hostile submarines. Thanks to his work, it is now impossible even for a submarine. travelling under water to enter an English or French har- bor without being detected. His interesting article describes the experiments which led to the adoption of a remarkable microphone submarine detector —En1Tor. ET a submarine dive below the sur- L face of the sea and it would seem utterly impossible to locate her. No eye can see her. If she plows along at a depth not greater than a hundred feet she can be seen in clear water from an aeroplane. But if she descends below that she is as invisible as any fish. Suppose that a submarine gave forth a sound of some kind, would it not be possible to devise some form of appa- ratus by which it could be heard? That was the starting idea of the experiments that I conducted for the allied Govern- ment. It is not a new idea. Professor Tissot was hard at work with the original experiments and had already used micro- phones for this purpose. Professor Fessenden had made some brilliantly suc- cessful experi- some form of apparatus which would pick up the sounds sent forth by a sub- marine, not deliberately, but involun- tarily. Strange Noises of the Sea At once the beating of the propellers of a submarine suggests itself. It is not characteristic enough. Motor boats, steamships, and other power driven ves- sels have propellers, and although their period of vibration is different from that of any other engine-driven craft, some other sound must be sought—something as distinctive as the call of a robin or the neighing of a horse, something that by no possible chance can be mistaken for an- other sound. I found what I sought in the weird, shrill hum of a submarine. Others had heard that hum ments withan apparatus of his invention, known as an “oscillator,” which showed how easy it is to locate a steamship in a fog or at night, provided that it sent forth sound waves. Tests of his instrument had also been made on submarines. But these inves- tigations were all conducted with a device which was installed for the deliberate purpose of making a rhyth- mic noise to be long before I be- gan my _ experi- ments. It was vibration.. But it is much too high in pitch for that, as I found by ac- tual tests. A ship’s engines pound ‘out vibra- tions not greater in frequency than fif- teen a second. You can almost count the beats. A pro- peller has a period much higher, but not high enough to produce the un- mistakable insect- detected. small microphones which he used in his ex- was needed was periments What Mr. Dubilier holding in his hand one of the like droning that comes from a sub- marine under the aken for engine

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HOW THE MICROPHONE PREVENTS HOSTILE SUBMARINE call The harbors of France and England are mapped out in imaginary squares, each bearing a number. In two stations, A and B, located a measured distance apart, microphone detectors are located. The stations A and B are in telephone communication with the wireless station C. The officer in station A adjusts his microphone until he hears the hum of the submarine most plainly; the officer in station B does the same. Imaginary lines drawn perpendicularly to the microphone diaphragms will meet at the exact spot where the submarine is to be found. The necessary calculation is performed in the station C, for the officer there in charge knows the exact distance between A and B and the angles (Upper Left-Hand Oval Insert:) First experimental microphone and container. This form of electrical ear heard too much because it was influenced by passing steamers as well as submarines. The hum of the submarine was drowned out by the pounding of steamer engines and the beating of propellers (Lower Left-Hard Oval Insert:) The microphone and containers were suspended as shown. A threaded rod, with a handle at the end, passed through a central hole. Two outer holes slid over guide rods. It was possible to screw the microphone up or down or to throw it bodily from side to side until the hum of the submarine was heard most plainly (Upper Right-Hand Oval Insert:) In the upper right-hand oval picture a system is shown which was experimented with in order to eliminate all sounds but the hum of the sub- marine. This involved the use of a contact maker and breaker which made and broke the circuit with the same frequency as that of the submarine’s hum. There was only one - 714

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SUBMARINES FROM ENTERING HARBORS made with the base line A-B by the imaginary lines running to the submarine. quick calculation enables him to determine exactly in what square the submarine is to be found. He sends a wireless dispatch to a torpedo boat to proceed at once to square 23 or 25, as the case may be. As the submarine moves, its direction is telephoned by the officers in stations A and B to the officer in station C. By wireless, the officer at C directs the course of the torpedo boat so that it follows the changing direction of the invisible enemy. Unless the submarine drops to the bottom and stops its motors, it must be inevitably caught A very when it rises to the surface circuit at first—a battery, a microphone and a receiver. If a contact breaker were put into this circuit, naturally a continuous noise would be produced, due to the rhythmic breaking of the circuit. By inserting a transformer and placing the contact breaker in the secondary circuit, this difficulty was immediately eliminated. In technical parlance, the contact breaker was of such a type that the phase could be shifted so that the waves would be broken at the crest. The system was fairly successful, but not altogether trustworthy, It eliminated extraneous ncises, but sometimes it also eliminated the very submarine hum vhich the experimenters most wanted to hear ‘ (Lower Right-Hand Oval Insert:) Eventually, a telescoping resonating tube was adopted, which was attached to the diaphragm, and which, being attuned to the hum of the sub- marine alone, excluded all extraneous sounds, such as the vibration of engines of passing ships and the beating of propellers 715

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716 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE surface of the water. The period of vibration is about seven hundred and fifty a second. To produce a hum so high in pitch a propeller would have to revolve at a speed much greater than we dare to give to the flywheels of steam engines. The Hum of a Power House is Identical With That of a Submarine . I soon convinced myself that the fine, shrill, almost singing note that can be heard when the Diesel engines are cut off and the submarine is traveling under power derived from her storage batteries is due entirely to her electric motors. The sound is unmistakable. Step into any central station where electric power is generated to light a city and you will hear the hum of a submarine. There is no difference to the ear. To devise a means of detecting this sound at great distances was the object of my experi- menting. The microphone at once suggested it- self as a suitable instrument. In my first attempts to detect subma- rines by their characteristic hum, the mi- crophone was sealed within a watertight container and the whole placed in the water. The apparatus was a failure. It could not withstand the pressure of water even at five fathoms. The container was crushed like putty in a strong hand. Since the depth at which the microphone was expected to work might reach forty fathoms, where the pressure was hun- dreds of pounds to the square inch, it was obvious that some method of re- sisting the water had to be devised. The container had a diaphragm on one side, against which the sound waves from the submarine impinged. Because of the water pressure the diaphragm could not vibrate freely, and hence the microphone was highly inefficient. Ears That Heard Too Much In order that the diaphragm might successfuly resist the external pressure air was forced into the container until its pressure equalled that of the water. The new form of apparatus was much more successful than that first used. Submarines could be heard beneath the water at a distance of five miles, and the apparatus stood up well, even at great depths. But it had the great defect of hearing too much. Not only was the hum of a submarine picked up with astonishing clearness, but other strange sounds of the sea as well—the vibration of engines in passing steamers, the beat- ing of propellers in water. A steamer sets the water vibrating with an intensity thousands of times greater than that of a humming submarine. In that deluge of sound the submarine could not be eas- ily detected. It was like trying to hear the thin, clear note of a violin under a railway trestle while a train was passing overhead. A kindred phenomenon is observed in radio stations. The wire- less operator calls it “static.” He elimi- nates static by tuning his apparatus to re- spond only to the signal that he wishes to detect. In order to make the microphone effec- tive an analogous system of mechanical tuning was invented. It was necessary to eliminate all sounds but that emanat- ing from the submarine to be located. You can understand how that is possible if you have noted the response of a piano to a violin. Draw your bow over any of the violin strings and sound a single clear note, and you will hear a faint response from the corresponding string in the piano. Of all the strings in the piano | only that one answered the violin. Why? Because that was the only string in tune with the violin note. The Invention of a Sound Sieve Clearly, some kind of sound sieve was wanted—something that would sift out everything but the singing submarine. Years ago an instrument maker, named Koenig, at the University of Paris, de- vised an adjustable resonator. It consist- ed merely of two telescoping metal cylin- ders. The cylinders were closed at one end except for a sound opening. If you wanted the cylinders to sing in unison with a vibrating tuning fork, you could do so by moving the cylinders upon each other. A point would be reached at whi the natural period of vibration of the air space within the cylinders was exactly © equal to that of the tuning fork, with the result that the resonating cylinders gave forth the same note as the tuning fork. While the cylinders were thus ad- justed they would respond to no other

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note. Still, they could be made to sing in unison with any other tuning fork merely by adjusting the telescoping cylin- ders. Playing a Flute to Analyze the Hum of . a Submarine It was this principle which was applied in the construction of a microphone which would respond to nothing but the singing electric motors of a submerged submarine. In front of the diaphragm of the microphone-container a telescop- ing tube was secured. To ascertain the natural frequency of vibration of a sub- marine’s electrical machinery a flute was played. It was found that a note could be extracted from the flute which cor- responded exactly with that emitted by the submarine. Experiments were then made with the flute in front of the re- sonating diaphragm tube. By pushing the tube in and pulling it out it was finally adjusted so that it sang with that note of the flute which corresponded with the hum of the submarine. The result was startling. The micro- phone now responded to nothing but the .» humming submarine. Ocean steamers POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 17 with great pounding engines within them passed unheard. Only the high-pitched note of the submarine reached the ear. A French submarine and a torpedo boat destroyer were placed at my disposal for experimental purposes. The sounds from the two never clashed; the submarine alone was heard. Other forms of sound receivers were tested, and we finally adopted one which gave most satisfactory results. In front of the resonator tube a diaphragm -was mounted, and to this a second resonating tube was attached. The double-tube res- onator was placed within a heavy cast- ing provided with a diaphragm, and into this container compressed air was pumpéd to offset the water pressure. One of the inserts on the double-page illustration shows the construction so that further explanation is unnecessary. The Electrical Ear and How it Hears This microphone, or electrical ear, as it may well be called, proved to be extra- ordinarily sensitvie. It could detect a submarine twenty miles away. And it behaved curiously like a telephone. Talk squarely into a telephone transmitter and 3% OES St BABES 2 emcee cath PS th of nets. The English Channel is a labyrin floats are straight, the En the surface; but when the They are suspended from floats. When the glish patrols know that nothing of moment has happened below y are askew, as in this picture, they know that a submarine has been caught

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718 the man at the receiver will hear you clearly; talk into the transmitter side- wise, and you will be heard less distinct- ly. So it proved with the microphone. When the singing note sent out by a sub- marine under water struck the micro- phone squarely it was heard much more distinctly than if the microphone were inclined to the sound waves. That made it easy to note in which direction the submarine was traveling. The micro- phone had merely to be turned until the hum was heard most distinctly. To determine the exact spot where a hostile submarine might be at any given moment two microphones were em- ployed. Imagine two stations, A and B, along a coast line; imagine a microphone detector in each, and imagine a central station, C, the headquarters of a naval officer in telephonic communication with stations A and B. The microphone de- tectors at stations A and B are turned from side to side until the submarine is heard with the greatest distinctness. Imaginary lines drawn perpendicularly from the microphones would meet at the point where the submarine is to be found, and the length of the line can easily be POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

calculated by a simple trigonometric] process. For the purposes of defense the har. bors of the world are usually ruled off by artillery officers into imaginary squares, which are plotted on a map, Suppose that a submarine is in square 23, The officer in the central station C is told by the microphone operators in stations A and B the exact inclination of their in- struments at the moment. He carries out a rapid trigonometrical calculation, and the result shows him that the submarine must have been in square 23 at the time his data were telephoned to him. At once he sends out either a fast motor boat, armed with a gun, or a torpedo boat destroyer, to square 23. Tracing the Course of an Invisible Sub- merged Submarine But, you naturally object, the subma- rine under water is not at rest. It is mov- ing at the rate of ten knots. By the time its pursuer reaches square 23 it may be in square 35. The objection is very easily met by wireless. As soon as the pursuing boat starts for its prey its wireless operator

Below the surface of the water a submarine is sichtless, for the periscopes have been withdrawn. The British have taken advantage of this. a raft, as here shown. Railway rails are suspended from If a blind submarine collides with them, its shell is crushed in. Death and destruction inevitably follow

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listens for signals from the central sta- tion C on shore. The men in stations 4 and B follow the moving submarine with catlike vigilance, each second. They turn their instruments this way and that, al- wavs listening, until the sound that comes to them is clearest. They telephone from minute to minute to the central station. “Heading north east” is the word from station A. “Heading north northwest,” telephones the man at station B. And so, the course of the invisible terror beneath the waves is constantly followed with an accuracy that must seem as uncanny as it is simple. The Blind, Helpless Submarine The captain of a hostile submarine has no means of knowing that he is pursued when he is submerged. He is absolutely blind. His periscope avails him not. Sooner or later he will rise to the sur- face, like a whale, if not to blow, at least to see. Certain destruction awaits him. The instant his periscope juts out of the water a hail of bullets rains upon his deck. His enemy rushes upon him, rams him and crushes in the thin shell of his submarine like paper. The experiments here de- scribed resulted in a com- plete defense against sub- marines lurking in harbors and waiting for a chance to torpedo a vessel about to put out to sea. Obviously the same prin- ciples can be used on ship- board. I have myself con- ducted experiments along lines indicated by Professor Tissot and Professor Fes- senden with encouraging results, and I know that microphone detectors are now used on English ships to pursue as well as to avoid German submarines. If the Germans practically have aban- doned submarine warfare, it is not only because the volume of British shipping is so enormous that a hundred submarines could not hope to wipe it out completely, but also because the microphone has been able to ferret out underwater craft, even when submerged at great depth. The first American linotype machine has recently arrived at Tripoli. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 719 t Wireless Tower Wrecked by a Gale Stops a Train During a terrific gale last fall the new three hundred and four foot wireless tower at Tufts College, Massachusetts, was blown over and a section dropped thirty feet in front of an express train speeding to Boston. The quick wit of the engineer in throwing on the brakes and reversing the throttle prevented a very serious accident. The tower carried away telephone and telegraph wires and also blocked a main arm of the railroad for several hours. The steel structure was to have been the highest wireless mast in New Eng- The wireless tower, wrecked by a gale of wind, lay on the ground twisted like a snake land, the foundation being ninety-six feet above sea level, mak- ing possible radio con- The tower of the Tufts Wireless —- Europe. Station fell directly across a rail- An umbrella antenna way track was planned to radi- ate from the top, but had not been installed at the time of the accident. This was the only tower of its kind in the country and the height was to have been increased to five hundred feet. Guy wires supported the tower at every one hundred feet, but were not sufficient to support it adequately against a high wind. The hollow steel structure was about six feet square from top to base. During 1914 the’ marketed production of natural asphalt in this country was 77,588 short tons, with a value of $630,- 623.

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720 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Removing the Rim from the Tire A tool has been de- signed which is in- tended to lessen the labor of taking off rims. It removes the rim from.the tire, not the tire from the rim —the ordinary method. No hammering or pry- ing is necessary, and the rim and tire are therefore undamaged by the operation. To remove the rim the tool is placed with the three hooks over the edge of the rim and the lever pressed down. This motion contracts the rim, caus- ing the one end to lap over the other, and the whole to come off the casing easily. The tool consists of a handle, to which are at- tached three arms with hooks, and a_ lever. When pressed down this lever causes one arm to be pulled, thus loosening the rim and lapping that end of the rim under

This clever tool reverses the usual tire-changing process. It removes the rim from the tire, not the tire from the rim From Swimming Tank to a Theater A queer transfor. mation made in a big amusement park at Ocean Beach, Cal., is the change from a large concrete pool, originally used for diy- ing and swimming per- formers, to a theater pit for the free vaude- ville staged on the boards at the end, After the tank was remodeled at the shallow end to allow the @ audience to walk down an incline, a stage was fitted up at the deeper end, and the seats were set on the concrete floor in rising tiers. The gradual rise of the floor of the pool from deep water to shallow water gave just the right slant for the seating, so that every spectator may see over the heads of all in front of him. <A can- vas roof and side-sup- ports were added to complete this novel outdoor vaudeville house.

the other

end. Wobbly wheels,caus- ed by ham- mering them off, are im- possible whenthe tool is used. The remov- er can be used with any split rim now in use, anda modification of the de-

It is esti- mated that by mere waste, caused by coins rubbing together, the world loses one ton anda quarter of gold and eighty - eight tons of silver annually. Gold coins are said to be rolled in bar- rels by the

vice is made A stage was set up at the lower end of this swimming tank, Chinese for for use OM and the inclined floor gave the correct slant for the seats. the dust knocked off. solid rims. The pool seemed made for its new purpose

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POPULAR SCIENCE MONTHLY AND WORUD’S ADVANCE 721 — A private automobile for a sixty-thousand-dollar race horse A Motor Car for a Horse In order to keep the famous race horse “Uhlan” from the dangers and draughts of an ordinary railroad horse-car, Mr. C. K. G. Billings, the famous horseman and “Uhlan’s” owner, has built a large motor truck in which the horse is trans- ported from race to race. A large, box-like body was built on the truck chassis, high enough to clear the head of the standing animal. The in- side of the car is padded, and even if the car should rock and sway on its heavy springs the horse would not be injured. “Uhlan” is valued at over sixty thou- sand dollars. As a highly trained race horse is subject to colds, the utmost pre- cautions have to be taken. A car very similar to the one used by “Uhlan” is at present in the service of the American Ambulance in Paris. In- stead of carrying one race horse, the ma- chine now carries fourteen wounded men at a single trip. Training Militia Officers at Army Aviation School An announcement of Secretary of War Garrison to the Aero Club. of America states that in the near future officers of the Flying Corps of the militia of the various states will be given training at the United States Army Aviation School at San Diego, California. Provision is made for mileage, sub- sistence and quarters of those who are authorized to attend, but pay from the Federal funds during the period of at- tendance is not authorized. It is doubtful whether any officers of the militia can be trained at the present time at the school, as it is already so short of aeroplanes that instead of having two or three for each officer-pilot, as they have in European countries, a number of army officers have, together, only one machine in which to train. Consequently a number of officers, because of lack of equipment, cannot get sufficient practice. Sixteen states have become interested in the formation of a Flying Corps through the Aero Club’s efforts, and are now ready to take up the work of de- veloping this branch of the service as soon as they can get funds for aeroplanes and for the upkeep of the corps. These states are: Arizona, California, Illinois, Iowa, Florida, Maine, Missouri, Nebras- ka, New Jersey, New York, Ohio, Okla- homa, Pennsylvania, Texas, Vermont and Wisconsin. Several of these states are already provided with aeroplanes. New York has two machines, an aeroplane and a flying boat; the latter for the use of the Naval Militia.

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ae

Did slide Potomac River

Mount Vernon, the home of Washington, showing how the Potomac River had been eating into its banks and what the engineers have done to save it from further attacks Saving the Home of Washington I’ the thousands of Americans who have enjoyed the magnificent view of the Potomac from the broad lawn of the mansion at Mount Vernon, few, if any, realized that the bluff on which the home of George Washington stands was in danger of sliding into the river and being washed away. This bluff is about one hundred feet high and is composed of layers of clay, sand and soft sandstone over a stratum of impervious clay. Undercutting of the foot of the bluff by the river and the fact that the soft sandstone over the clay was continuously wet, resulted in landslides, which doubtless have occurred more or less frequently for centuries. In Washington’s time, a part of the steep slope from the edge of the lawn to the river broke away and slipped toward the river. - ' Recently it was discovered, by finding a break in the lawn in front of the man- sion, that a new slide had developed. If it were not stopped, it would destroy at least a part of the lawn and the beautiful trees along the bluff and might eventually extend back until the mansion itself was endangered. Two methods to stop the earth move- ments were discussed. One was to hold the earth back by driving piling. But this was like making local applications without a thorough diagnosis of the case in order to remove the cause. The other method was to make a study of the strata which made up the bluff and the underground water, and then to see if the water could not be drained off. This second method was adopted as the one which would likely result in per- manently stopping the slide. The surface of the clay was the plane on which the bluff was sliding. A small drainage tunnel was driven into the sand- stone at the level where it joins the clay below. <A considerable flow of water started at once from the tunnel and kept up for several months. Then the flow gradually diminished until it is now rel- atively small and constant. © The diagnosis of the engineer was correct. With the removal of the water from the overlying strata, and from the sliding plane under the sandstone, the earth movement has stopped. At the water’s edge a masonry retaining wall has been built to stop the undercutting of the bluff -by the wave action of the river. No further trouble is likely to occur now that the causes of danger have been removed.

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OT long ago newspaper readers N were surprised to learn from news- paper headlines of the startlingly success- ful transmission of wireless telephonic speech from Arlington, Va., westward over the entire North American continent to Mare Island, California, a distance of two thousand, five hundred miles. This was astonishing enough, but when the next morning’s papers reported that human speech had been transmitted wire- lessly as far as Honolulu, Hawaii, about five thousand miles of land and sea, the earlier result was completely eclipsed. Later still, Arlington talked wirelessly with the Eiffel Tower in Paris, across the Atlantic Ocean. For the past two or three years wire- less telephony has not been largely ad- vertised ; in 1908 and 1909, however, its possibilities were greatly over exploited. As a result of the absence of publicity since about 1912 the new accomplish- ment of talking four thousand, nine hun- dred miles comes before us as an indica- tion of a radical change from former methods of wireless telephony; the in- ference is that, since the distance covered is great, some real change of principle has been made. Nothing could be farther from the actual fact; wireless telephony in its earliest days was effected in exactly the same way as it is today. Increases in distance have come mainly as a result of using more powerful sending instru- ments and more sensitive receivers. The development of these devices is a matter of great importance, and has been a tre- mendous undertaking. Nevertheless, it should be remembered that wireless tel- ephony itself is not a new thing. The transmission of articulate speech by modulated ether waves of the sort used in wireless telegraphy has been accom- plished many times since its inception in 1900 or thereabout; radio-telephony, as this modern sort of “wireless” is offi- cially named, began some fifteen years ago with poor communication by simple words over a distance of approximately one mile. The speech as first received was masked by interfering sounds, much as on a noisy telephone wire, but the de- Wireless Telephoning Simply Explained By John L. Hogan, Jr. fects were eliminated one at a time, un- til, in 1906, it was demonstrated that over distances of some twelve miles wire- less conversations were clearer and bet- ter than those held over wire. The next year radiotelephony was demonstrated as an operating possibility when Fes- senden wirelessly transmitted speech from Brant Rock, near Boston, Mass., to New York and Washington, distances of two hundred and four hundred miles respectively. What Is Wireless Telephony? The interest aroused by the new work of the American Telephone and Tele- graph Company, whose engineers are largely responsible for the development of the specific instruments used in tel- ephony from Arlington to Honolulu, has caused much speculation as to what radio- telephony really is. The idea of sending articulate sounds for miles over a wire and then reproducing them seems weird enough, but when the same process is accomplished without any visible con- necting medium, except the earth, the re- sult seems more than ever mysterious. Yet when one understands the natural laws which are applied in transmitting speech electrically, one seems no more marvellous than the other. Speech it- self is not looked upon as wonderful, yet the mechanics of articulate sound are little less complicated than those of tel- ephony. To understand the real action of wire- less telephony it is necessary to ‘realize what speech itself really is. Vocal sounds, like all others, are produced by mechanical vibrations which reach the ear (usually through the air) and there cause similar vibrations in an auditory system, thus producing upon the brain the sensation of sound. In the produc- tion of speech waves, air is expelled from the lungs and, passing through the vocal system of the throat and mouth, is set in vibration. Nervous control of the or- gans of speech permits us to alter the vigor and frequency of the air-vibrations produced, and to combine the various frequencies of vibrations as we may

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724 choose. This faculty gives us the ability to signal to our neighbors according to the conventional sound-code called “lan- guage.” - In considering this it must be noted that the air lying between a speak- er’s mouth and an auditor’s ear does actually move with the energy of the speech waves. ~ The motion is not that of a current, for the air particles do not pass the entire distance from speaker to hear- er, but is rather that of a series of im- pacts between successive molecules of gas in the atmosphere. In case a simple clear tone is sung, all the molecules oscil- late back and forth according to a simple law of vibration. Each one strikes its more distant neighbor and, giving up its energy to it, then rebounds against that by which it was impelled in the first place. When the sound wave to be trans- mitted is complex, such as that repre- senting a consonant (the letter B, for ex- ample), the path traveled: by each mole- cule is also complex; the movement of the particles may be predetermined ac- curately, nevertheless, by adding together all the component frequencies of vibra- tion which go to make up the sound being transmitted. It is this actual move- ment of each molecule, with exact fidelity to the vibration which set it in motion, that makes possible the transmission of speech by electricity in either the wire or the wireless telephone. How the Ear Hears Since sound-waves travelling in air are based upon a purely mechanical motion of the air particles, it is evident that it should be possible to secure a similar mechanical vibration in any body upon which ‘the air waves strike. And this is what happens when a sound wave reaches the ear. The small diaphragm forming the ear-drum is set in vibration with the same frequencies as those which caused the sound-wave. This ability of the air-waves to pro- duce motion is not confined to effects produced upon the ear-drum, however; any diaphragm offered to them will vibrate in exactly the same way. The motions of such a diaphragm may be registered upon a wax record, as in the phonograph, and the original sounds thereafter reproduced by reversing the recording process and causing the record POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE to move the diaphragm through its orig- inal series of paths. Or the motions of such a diaphragm may be used to change the intensity of an electric current, so that the sound variations in the air may be impressed upon the apparatus con- nected at the distant end of a wire, through the medium of electricity. When the variations in the electric current im- posed by the action of the voice are caused to move a diaphragm at some connected point, and force this dia- phragm thus to reproduce the original speech waves, wire telephony is ac- complished. If the electric current which is modulated or altered in accordance with the original sounds is caused to set up radiating electromagnetic waves in the ether of space, and if these pass toa distant receiving station and there re produce their origina! vibrations by caus- ing identical movements of a receiving telephone diaphragm, radiotelephony is effected. ‘ The three processes of speech trans- mission, viz., mechanically through the air, and electrically by wire or by wire- less, are identical in the basic principle that sound vibrations are impressed upon some medium capable of carrying them to a receiver, and there are reproduced. The electrical process is merely a little more complicated by the interposition of a traveling electric current in a wire, or a traveling electromagnetic wave in space. These constantly connect the transmitter and the receiver, and, by changes in character produced by the original sound waves, reproduce their motions at the telephone held to the list- ener’s ear. The Essentials of a Wireless Telephone Apparatus The wireless telephone, then, requires three important elements for its opera- tion. First, there must be a generator of a continuous stream of electromagnetic waves which pass from sending to re ceiving stations constantly and upon which speech vibrations can be carried. Second, there must be an instrument which will modulate this stream of waves according to the voice vibrations to be | | transmitted. Third, there must be a re ceiver which will reproduce accurately the variations in the waves and so make —

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POPULAK SCIENCE MONTHLY AND WORLD’S ADVANCE 1725

the later arcs, alternators and spark systems of other investi- gators, including Goldschmidt, Lepel, von Arco, de Forest, Majorana and Joly, have all been capable of generating more powerfyl streams of waves than it has been possi- ble to control efficiently. Simi- ’ larly, the receivers as used in modern wireless telegraphy have more than = sufficient rapidity of response and deli- cacy to reproduce speech waves »| transmitted by wireless. Fur- ms, ther increases in their sensi- tiveness have been made re- cently by the addition of amplify- ing relays to magnify the received sounds, but in every case this in- crease in sound strength has been accompanied by a disagreeable magnification of disturbing sounds from atmospheric inter- ference which has _ prevented commercial use of the over-deli- cate instruments. The real limit of radiotelephony has there- fore been in neither the gen- fwa\ erator nor the receiver, but in bier the modulating apparatus. It ire is in the development of this ‘MYES part of the transmitter that eed the engineers working m under Mr. Carty of the

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The Eiffel Tower, Paris, where the great French wireless receiving station heard the voice in Washington, more than three thousand miles away across the Atlantic. Unfortunately the experiments between Arlington and Paris could not be continued. The Eiffel Tower is so essential in war that the French government has been compelled to abandon its interest in the work

SS Gi OLED IEEE ARE

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726 The Bell System Aids the Wireless Telephone As President Vail said: “So far as the perfection of the wireless telephone goes, there has been no new basic itiven- tion, merely a perfection of sending and receiving instruments. Of course, in the perfection of these delicate machines there have been minor inventions.” The work of the tele- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE fornia, two thousand, three hundred miles away, and at Darien, Panama. Soon after midnight the engineers listening at a newly installed receiving station near Honolulu, Hawaii, reported that they were receiving portions of the speech direct over the four thousand, nine hun- dred miles separating them from Arling- ton, and that, although the words were very loud, they phone company on ae radio, following Cs the inauguration of transcontinental telephony by wire, has been carried forward a step at a time for nearly a ar. so ~~ , m3 pers ae re | ani |e Gah mene” = . sie year. Speech was = first sent from an be 4 experimental _ sta- Ik by : tion at Montauk a A Point to the New York offices, then two hundred and fifty miles to Wil- mington, and then one thousand miles could be under- stood only when atmospheric and other disturbances were slight. What's the Good of the Wireless Telephone? The _ practical utility of radio- telephony has been much dis- cussed. Generally it is believed that the wireless tele- . phone has at least two fields of serv- toa specially erected station off the Southern coast of Georgia. The results of these trials were MPS UX EX nt = -_re oy BON EY XZ, Ms Yi, S fy BAS . iy ‘Mit sew = ¥s Ly ' 4 gm aY em > Saew ~ ice, which are pe- culiarly its own, to wit, inter-con- nection of ships and isolated points more than enough to indicate still on land, where it is not economical- ly possible to em- greater _ possibili- ties for the appa- ratus developed in the course of the experiments, and therefore arrange- ments were made to borrow the antenna of the great Naval Radio station, at Arlington, Va. The new type of trans- mitter was installed there, and prepara- tions made for radiotelephony over longer distances. On August 27 a suc- cessful test was made from Arling- ton to Darien, Isthmus of Panama, two thousand, one hundred miles away. On \September 29, in the early afternoon, Leech from New York sent to Arling- ton, by wire, was relayed to the radio- telephone and transmitted to San Fran- cisco, by wireless, over two thousand, five hundred miles. At the same time the talking was heard at San Diego, Cali- Tower at Arlington, Va., from which the wireless telephone reached Hawaii and Paris at the same moment ploy a_ telegraph operator, and in conjunction with wire telephones as long-distance “trunk” lines. The special feature of the wireless telephone is the freedom from distortion with which it transmits speech, and this, taken with its elimination of line main- tenance expense, indicates a commercial future for the method when the ap- paratus shall reach a point of sufficient development. The engineers of the tele- phone company are to be credited with aiding the commercial development of the wireless method. It was largely due to their fine experimental investigations that the magnificent feat of communi- cating by articulate speech from Arling- ton to Honolulu and Paris was accom- plished.

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Special Theater Seats for Children Nearly everyone has been bothered, when sitting in a motion picture theater, by having a child in the seat just in front of him climb up on the arm of the chair or get into the seat in such a fashion that the child can himself see, but greatly in- conveniencing those behind him. A new invention in the way of chairs, designed by POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 727 Trawlers in War and Peace The efficacy of trawlers in Britain’s campaign against the German submarine has directed considerable attention dur- ing the past few months to these diminu- tive steamers, built originally for fishing purposes, but through pressure of. cir- cumstances commandeered for commerce protection. As a war Raymond D. Weakley, of St. Louis, Mo., is ex- pected to do away with this annoy- ance. Mr. Weak- ley’s seat dif- fers little in design and construction from the present opera chair. The front two- thirds of the seat portion vessel, the trawler must rely upon an unvarying rule of see- ing the sub- marine be- fore the sub- marine sees it. A single shot from one of the trawler’s light guns will end the career of a sub marine. Just how the trawler is bolted to an independ- ent pair of seat-rest castings which are hinged to the for- ward end of the regular castings. The apparatus makes it possible to push the adult seat forward and upward. The en- tire seat moves toward the back, where it locks automatically in the new position. With this movement the adult seat, which is seventeen inches deep and fifteen inches above the floor, is convert- ed into a child’s seat, eleven inches deep and twenty-four inches above the floor. As the back and seat of the chair, when in the child’s position, are in the same proportion as that of the adult seat of the ordinary opera chair, the child is perfectly fitted, and seated, as in the best public school chairs, while his eye is brought to a level with the adult’s. Children constitute about forty per cent. of the average moving picture theater attendance, and the use of the new style seat is expected to popularize the moving picture theater still more with adults as with the youngsters. into the child’s seat The adult seat is raiséd nine inches when it is converted works in time of peace is not so well known. A large net is trolled be- hind the steamer on the end of a hawser. The cable is fas- tened to the ‘bow of the boat, and when the net is filled the trawler is ‘brought about in a short circle... The net is then slowly drawn in, hoisted aboard, and the fish sorted. The nets trail close to the bottom—so close, in fact, that submarine telegraph cables are often dragged from their beds. The child can see over the heads of the adults, and does not cut off the view of those behind

Page 26

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Page 27

How the Submarine ‘‘F-4’’ Was Lifted Out of Three Hundred Feet of Water By Lieutenant-Commander Julius Augustus Furer, Naval Constructor, U.S.N. Lieutenant-Commander T’urer, the author of this article, planned and directed the raising of the “F-4” in all its phases. Therefore, his highly interesting and simple exposition of the engineering methods employed may be regarded as trust- worthy in every particular. A Board of Inquiry, headed by Rear Admiral Busch, ‘ attributes the disaster to a leak, resulting from a corroded battery lining and cor- roded rivets, and to the failure of the boat, through poor diving qualities, to re- spond promptly to a tilting of her rudder, which should have returned her to the surface. l Government on May 2, 1913.—EbiTor. The “F-4’ was a fairly new submarine, having been accepted by the ; , g y HEN the “F- 4” was. finally - located the day following her disappearance off Honolulu on March. 25, it seemed at first hopeless to salvage her on account of the weight to be lifted and the difficulty of making lines fast at the great depth order to dis- place the water from the ves- sel it would have been nec- essary to de- liver air below at one hundred and thirty-five pounds _ pres- sure —a prob- lem in_ itself, as the pres- sure at the compressors would have had to be maintained at of three hun- dred feet. The most di- rect method of lightening a submerged vessel is to close the acci- dental aper- tures and to pump out enough water to make the craft buoyant. In the case of the “F-4” this method of attack was en- tirely out of the question, because of the great depth of water. All submarines are equipped with an internal air salvage line, having an out- board connection for the purpose of blowing the vessel free of water in case of just such an accident as that which occurred, This provision did not solve the salvage problem in this instance. In ( The four divers who did the under-water work in con- nection with placing the pontoons from August 2|st to 29th. The work was extremely arduous. left to right the men are: Chief Gunners’ Mate Evans, Chief Gunner’s Mate Agraz, Gunner's Mate O’Brien and Gunner's Mate McMillan. divers who went down to three hundred feet, as they had returned to New York in June lf about one hun- dred and sixty pounds to overcome the friction. in the great lenzth of small hose leading to the vessel, Besides air salvage was finally disqualified be- cause, even under the most favorable circumstances, it would have relieved the vessel of only part of the water, and because the ballast tanks could not have been thus emptied. Any plan devised for recovering the submarine, therefore, had to be based on the proposition of lifting two hundred and sixty tons of dead weight from a depth of three hundred feet under salving conditions probably unprecedented. From These are not the

Page 28

THREE HUNDRED FEET 1. A dredge was anchored at one end, and the other end was moored to the sub- marine. It was necessary to have a fixed craft available for receiving the ends of the slings temporarily because it was never certain that the loop had been dragged to the desired position under the vessel until an inspection had been made by the divers 2. Four specially constructed windlasses were installed on two mud scows—two on each scow. The lifting cables were passed up through the mud pockets and secured to the windlasses. The craft was thus suspended in four slings. Wire cables were used, which chafed and eventually parted oa az the wire cables broke, a towing strain was kept on the dredge by a tug 3. Atter was lifted,

Page 29

Why Pontoons Could Not Be Employed in the Early Stages The buoyancy of pontoons is ordina- rily used to float a wreck when the ves- sel itself cannot be given positive buoy- ancy. In such cases the lift to be accom- plished is usually small—sometimes only a few feet, which, by taking advantage of the tide, may be sufficient to take the ship off the bottom. If a num- ber of lifts must be made in order to bring the vessel up, the pontoons are sunk almost to the deck level at low tide. The lifting cables are then hove taut. As the tide rises the pontoons are also pumped out. When the vessel is clear of the bottom the pontoons, with their suspended load, are towed inshore at high tide until the vessel again grounds. Sinking the pontoons and taking in the slack of the chains is repeated at the next low tide. If there is much rise and fall of tide, a considerable lift may be accomplished at each step. In this man- ner the wreck is gradually worked into shoal water or even landed in drydock. In the case of the “F-4” the conditions for pontoon lifting were not favorable. The difference between high and low water is only about one and one-half feet off Honolulu. As the vessel lay in three hundred feet of water, a great many lifts would have had to be made. For these reasons it was necessary to bring the submarine up by mechanical means. Four specially constructed windlasses were installed on two bottom-dumping mud scows—two on each scow. The lifting cables were passed up through the mud pockets and secured to the wind- lasses. Instead of securing the cables to the vessel, the loops of the cables were swept under the submarine and both ends taken to the windlasses, thus suspend- ing the craft in four slings—two at about one-third the length from the bow, and two about the same distance from the stern. How the Slings Were Placed Under the ga ee Placing the slings under the’ vessel was the most difficult feature of the sal- vage work. Four wire cables were used at first. A dredge from which the boom POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 731 and bucket gear had been removed was used for the central unit of the salvage plant. This dredge was anchored at one end in the usual manner, as shown in the illustration. The other end was moored to the submarine by means of the lifting cables which were eventually transferred to the scows. It was necessary to have a fixed craft available for receiving the ends of the slings temporarily, because it was never certain that the loop had been dragged to the desired position under the vessel until an inspection had been made by the divers. ° A New Record for Divers The divers, while ‘the vessel was in three hundred feet of water, set a new world’s record for depth. The Bureau of Construction and Repair of the Navy De- partment had been experimenting for some time on deep-sea diving. It so happened that these experiments were brought to the point of practical appli- cation just before the accident to the “F-4.” Four divers, in charge of the officer who had been conducting the ex- periments, were ordered from the New York Navy Yard to Honolulu as soon as it became apparent that the vessel could not be dragged into shallow water. The diver does not wear a suit of spe- cial character when working in great depth as is the popular impression. The difference as compared to shallow water procedure lies entirely in the method of supplying air to the helmet and in the scientific restoration of the diver’s body to the normal state by gradual decom- pression as he comes up from deep water. Air is supplied from flasks charged to a high pressure—suitably re- duced before being delivered to the di- ver’s helmet. The dangers in deep-sea diving are due principally to the absorp- tion of nitrogen by the fluids of the body, on account of the high pressure to which the lung tissues are subjected and to the extreme exhaustion accompanying any kind of manual labor. For the latter rea- son the divers could not do heavy work at the three hundred-foot depth such as can easily be done by men working in shallow water. After innumerable difficulties all four slings were swept under the vessel by means of tugs and the ends transferred

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Steere 2 BS SST aE 732 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Dredge and scows used during the first phase of salvage work. Waiting for a diver to come up from 300 feet of water. In order to effect decompression gradually, the divers were sometimes two and a half hours in making the last one hundred feet back to the surface from the dredge to the scow windlasses. This took from April 10 until April 21. On April 22 lifting the submarine by winding up the cables on the windlasses was'started. As the cables were wound up, a towing strain was kept on the . scows, thus bringing the submarine into shallower water. One of the Lifting Cables Breaks After lifting about twelve feet one of the cables parted in the loop, due to chafing on the bilge keels. This cable was one of the first to be placed, and had consequently suffered from chafing for almost two weeks, due to the continual motion of the dredge and of the scows in the swell. The broken sling was re- newed and lifting was continued until the vessel was in two hundred and seventy-five feet of water. Bad weather now set in and accelerated the impair- ment of the cables, causing them to carry away one by one. It was now apparent that chain would have to be used for that portion of the slings in contact with the vessel. _ The use of chain for the loop of the slings was considered when the salvage plan was first being developed, but was rejected, because chain does more dam- age to a vessel and is much harder to place than wire rope. These disadvan- tages had now to be accepted. A fifteen- fathom shot of two and five-eighth inch chain was accordingly shackled in to form a loop of each sling. The dredge was again moored as before by sweep- ing one and three-quarter inch wire lines under the bow and the stern of the sub- marine and bringing the ends to the corners of the dredge. The chain slings were finally placed in the same loca- tions as had been occupied by the wire rope slings. Bringing these combina- tion slings to position was considerably more difficult than placing the wire cables, because they were even heavier and more awkward to handle than the latter. After working twenty-one days, four slings were again in place under the vessel. As the submarine was lifted a towing strain was kept on the dredge by a tug. This in turn brought a towing strain on the submarine. The arrangement proved moré satisfactory than towing directly on the scows, because it permitted the scows

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to ride in their normal state of equi- librium. Once the slings had been made fast to the windlass drums, lifting was fairly rapid. After the windlass shafts had been filled with one layer of cable, it was necessary to cut off the wound-up por- tion and to shift to a new hold under the hook bolts. It was impossible to wind up a second layer, because of the enormous loads on the slings. One layer of cable corresponded to a lift of fifty-eight feet. The shafts could be filled in about two hours of actual lift- ing, but the work of cutting off and shifting to a new hold took considerably longer. In spite of every effort one of the stern lifting slings could not be located quite as far aft as desired when it was put on, consequently it did not plumb the mud pocket through which it passed. This was immaterial in deep water, but as shallower water was reached, the sling began to bind on the framing of the pocket. When a depth of fifty feet was reached, it became necessary to shift the sling to a more vertical posi- tion: A Storm Rises and the Submarine is Dropped for Safety While this work was POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 733 going on a heavy ground. swell set in very suddenly. The swell increased rapidly and in a short time high surf waves were breaking near the subma- rine. The waves and the undertow: from the reef caused the scows to charge back and forth with tremen- dous momentum. The after sling could not now be replaced in time to résume operations. It was apparent that con- siderable damage would be done to the submarine by the slings and that possibly the entire plant would be wrecked if an attempt were made to ride out the bad weather. The slings were accordingly cast off and the scows towed into the harbor. The heavy seas continued for a num- ber of days. As soon as‘the swell had subsided ‘sufficiently, divers were sent down to examine the submarine. They reported that the forward slings had ruptured the shell and had caused the . collapse of some of the framing one- third of the distance from the bow. This made it unsafe to continue opera- tions ‘by the windlass method, as there was danger of breaking off the for- ward end of the vessel while pass- ing through the channel. This would have blocked the harbor to naviga- \ tion. As the submarine End view of a lifting scow. Operations are suspended waiting for a diver to come up. Note the heavy purchase in the right foreground, leading to the hoisting engine for turning the windlass

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734 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ' now lay in somewhat less than fifty feet of water, it was possible to apply the pon- toon method of lifting, but it was still im- practicable to follow the orthodox pro- cedure of lifting a few feet and towing to a new landing, because conditions were such that the vessel had to be raised in one operation to a draft of not more than twenty-five feet. This draft was fixed by the depth of water over the blocks of the drydock in which the vessel had to be landed. To meet these requirements six spe- cially designed pontoon cylinders were sunk alongside of the submarine, as shown in the illustration. The plan fur- ther called for the use of six chains rove under the vessel and passing through hawse pipes in the cylinders. The arrangement consisted in effect of a lifting of the submarine in a cradle made up of six chains. The combined lifting capacity of the six pontoons was four hundred and twen- ty tons. A margin of one hundred and sixty tons was allowed for breaking the vessel away from the bottom and for any railure to utilize all of the buoyancy available in the pontoons. Carrying the Submarine into Port on Pontoons The chains were first of all worked under the submarine in predetermined positions, two forward, two amidships and two aft. The two chains of a pair were spaced sixteen feet apart so as to correspond to the distance between the hawse pipes. The pontoons were planted by means of a wrecking scow which was moored accurately over the submarine. The two cylinders of a pair were towed to the scene of operations and placed one on each side of the scow, directly over a pair of chains lying on the bot- tom as shown in the illustration. The ends of the chains were now fished up through the hawse pipes and the cylinders submerged by opening the flood valves. They were kept under con- trol while sinking by means of five-inch manila lines made fast to the ends and taken to the hoisting engines on the scow. The process consisted, therefore, in threading the pontoons onto the chains. After the pontoons had landed on the bottom the chains were adjusted so as to leave the necessary amount of slack to permit the pontoons to rise just clear of the vessel on becoming buoyant. A clamp was now fitted to each chain by the divers, just above the hawse pipe. The clamps consisted of two steel cast- ings, moulded to the shape of the chain links and of such length that they span- ned the hawse pipes. By means of four heavy bolts the two halves of the clamp were drawn together. These bolts kept the clamps from spreading and the chain from slipping throrgh when subjected to the lifting strain. After all six cylinders had been landed on the bottom alongside of the vessel and the clamps had been secured by the divers, the unwatering process was started. For this purpose torpedo air flasks, charged to a pressure of two thousand one hundred and fifty pounds were placed on a coal barge. The flasks were piped to an expansion chamber -which in turn was connected to a mani- fold. Twelve three-quarter-inch air hose lines were led from the manifold valves to the blowout valves on top of the pon- toons. A pressure of thirty-five pounds was used at the manifold for blowing out the water while the cylinders were resting on the bottom. The unwatering operation had to be watched very care- fully so as to avoid the danger of spring- ing the heads of the cylinders when the external water pressure was relieved on emerging. The method proved successful in every detail. The work of placing the chains under the submarine was started on August 21. All of the chains were in position on August 25. It then took one day to place each pair of cylinders. This could be done only during daylight, as the divers could naturally not work in the dark. On August 29 everything was ready for blowing the water out of the pontoons. This operation took about two hours from the time the air was fully turned on. One end of the sub- marine came up slightly ahead of the other, as was to be expected. The ves- sel was towed into the harbor suspended from the six pontoons as shown in the illustration, and was docked the follow- ing day.

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INCE the beginning of the European war, many compact, light wireless receivers have been proposed for military use. It is not at all difficult to build a tiny apparatus, which may be carried about, concealed in one’s clothing, yet which will receive “radio” messages from nearby powerful wireless stations. In this way, if a good electrical connection to earth can be made by way of a metal staff forced into damp earth, signals may be heard several miles. If, in addition, Another Pocket Wireless considering the liability of electric shock from the instruments, to carry enough batteries for sending messages even a mile or two would be more than any ordinary man would care to attempt. A small sender can be built, however, strong enough to send signals a few hundred feet, yet compact and light enough for a person to carry. Dr. H. Barringer Cox, of Bedford Hills, New York, has devised and built an interesting set of such portable appa- With his pocket wireless aparatus attached to his body, Dr. Cox, the inventor, becomes a : veritable radio station an umbrella is used to hide an “antenna” wire for absorbing the energy of the passing wireless waves, still greater dis- tances can be covered. All of this has “been done many times, and, in fact, small instruments for the secret reception of wireless messages have been on sale in various European cities for several years. To build a similarly portable wireless sender is a very much more difficult thing, however, because considerable power is necessary if messages are to be trans- mitted more than a few yards. Without ratus. The photographs herewith show the receiver and the way in which it can be hidden from view by strapping it underneath the operator’s coat. The heavy staff is used to connect with the earth; a wire run inside the trouser leg and connecting to a heel-plate can. be made use of when the stick proves in- convenient. Dr. Cox’s sender and receiv- er may both be worn on a single belt; and two men thus doubly equipped would be able to communicate secretly. Demonstrations have been followed

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736 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE with considerable interest. In one test a small sender consisting of a vibrator, operated by five dry cells, was connected to an automatic Morse transmitter and left to radiate its messages throughout the neighborhood. The receiver was then strapped on, and it was found that the signals could be heard quite distinctly some distance from the sender. When the transmitter was connected to a water- pipe as well as a bare vertical “aerial” wire, greater space could be covered. Similarly, when the receiver was lifted higher from the ground, the received signals were intensified. Dr. Cox uses in his apparatus a spe- cially built transmitter, the construction and operation of which he will not dis- cuss. Aside from this, however, the en- tire set of instruments is believed to be quite similar to those developed by others. Some further improvements are being made, and it is thought that this latest “walking wireless” may find use in the present great war. Electricity Sifts Sand The old-time sand sifters of our youth have been relegated to the scrap heap. Today in the modern foundry, and other places where screening of sand is a neces- sity, electrically operated riddles, or sieves, are installed. These sifters of sand work without interruption and do the work of ten men. This electric sand sifter does the work of ten men A crude water wheel which makes the river pump its own water to irrigate a California farm The electric riddle requires but one- sixteenth horse power to drive it and the apparatus can be run on a trolley along a line of twenty moulders, supplying per- fectly clean sand as fast as it is poured into its receiving pan. A River Which Pumps Its Water In a number of sections of northern California there are vast tracts of land which are watered only by irrigation and where the government has not yet car- ried out any reclamation projects, even on the smallest scale. The settlers and ranchers have improvised irrigation facilities of their own. These appli- ances, though crude and original, are none the less effective. Some of the best are used by the ranchers of the narrow winding valley of Klamath river. Numbers of large irrigating wheels, operated by the river current, are in operation here. These are about eighty feet in diameter, built of wood and strongly braced to withstand the current. At short intervals are placed “flood boards,” on cross-paddles, which, when immersed in the water, cause the wheel to revolve as the current strikes them. Attached to the outer rim, on each side, at short distances, are large box-like metal buckets, which are successively filled, hoisted and emptied into wooden flumes. Thence the water flows in side flumes into deep ditches dug along the high banks of the river. Many of these ditches are miles in length, and the water is distributed for leagues.

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VON HINDENBURG IN WOOD AND NAILS aA. Courtesy London Illustrated News. ; This great wooden statue of Field-Marshal von Hindenburg has been recently unveiléd in Berlin, Patriotic Germans drove nails into this, at five marks per iron nail, ten niarks for a silver nail, and as much over that as they wished to pay for a gold nail. 137

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BOWLING BEHIND THE GERMAN TRENCHES German soldiers bowling during a period of rest behind the firing line, Each of the warring armies allows its soldiers a regular rest every few days, Other troops take their places in the trenches, and those who have been relieved retire a short distance and are free to amuse themselves as they wish 738

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NOT MARTIANS, BUT EARTHLY SOLDIERS ‘nto te aad a bie @ International Film Service. A detail of French infantrymen awaiting an attack in a ruined town in the Champagne district. In these regions attacks are usually preceded by a cloud of gas, and all soldiers are equipped with the latest form of respirators. @ Underwood & Underwood. A French regimental band practicing in the gas-suffused ruins of a small village in the Argonne district. In order to protect themselves against the gas, the entire band is wearing the new hoods, which completely cover the head. When their regiment is in the trenches, the bandemen act as stretcher bearers, and the casualties are heavy 7329

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PROBLEMS OF TRANSPORTATION IN WAR aT British troops disembarking from a transport at the Dardanelles. Great barges are used to carry the troops and their provisions and equipment to the shore. (Above) Germans reconstructing a railroad bridge which had been destroyed by the Russians during the recent German drive through Russian-Poland 740 7100 |= ew — | tT ee ee

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PROBLEMS OF TRANSPORTATION IN WAR German engineers preparing to ferry a locomotive across the Vistula River. In the back- ground is the Warsaw-Praga bridge, destroyed by the retreating Russians. When this photograph was taken the Germans were already repairing the bridge, while locomotives and cars were ferried across the river on pontoons A French 155-millimeter field gun being towed ashore on a lighter near Sedd-Ul Bahr. In Gallipoli, advances have been made by slow trench-to-trench warfare. A large number of guns are needed to break down the enemy’s wire entanglements before starting an attack 741

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INFLATING A BALLOON WITH HYDROGEN The gas for these Engineers of the French Flying Corps inflating an observation balloon. alloons is stored under great pressure in long steel bottles, and may be easily transported In from one section of the line to another. A pile of these bottles is visible on the left. Germany these bottles are filled with waste hydrogen from the chemical works Sea acereenmngrnie Pan sauo picture continued on opposite page. Courtesy Illustrated War News Allied airmen have recently been baffled by a new German strategy which emulates the octopus and the naval use of smoke-screens. The German aviator carries, in addition to When in danger of being overtaken by a speedier bombs, a number of smoke balls. aeroplane equipped with a machine gun, the German throws out a lighted smoke bomb 742

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COMBATING AERIAL TERRORS © International Film Service Although the French and English have a number of airships, they have been used very little during the present war. The Italians, however, have used their semi-rigid dirigibles to a considerable extent since their entrance into the general conflict. The illustration shows an Italian dirigible, the “‘Cita di Tesi,” wrecked by Austrian shells in the sea off Pola te MES This picture continued trom opposite page. This develops a great cloud of dense black smoke. He then wheels and flies at an angle. e enemy is unable to fire at random for fear of wasting his precious cartridges, and by the time he has emerged into clear air the enemy is seen flying in another direction, ready to conceal himself again 743

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BATHING UNDER DIFFICUTIES British sailors “tubbing” on the deck of a submarine. War or no war, the English must have their daily tub. Sheets of canvas are stretched on the life lines. Water is supplied by means of a rubber hose. Although the apparatus is crude, it serves its purpose very effectively. The use of canvas bathing pools at sea is far from new. In times of peace warships let down tarpaulins supported on booms at the sides of the vessel and the sailors enjoy a sea bath without the dangers of deep-sea bathing. Even ocean liners used to introduce this as a novelty on trans-Atlantic trips, and _ the passengers always enjoyed the antics of the bathers, watching from the rail as the “greyhounds” of the sea sped on their way— and often passengers joined with the sailors in the refreshing “tub.” Folding canvas “sponge tubs” are part of the equipment of particular English travelers British sailors bathing in the North Sea and testing life rafts at the same time. This life raft is carried flat on the deck and if the ship sinks, floats free, with all on board A rough tub in Russian Poland. This crude trough is sunk in the bed of a small stream of running water, and the sides are retained by logs. German soldiers are waiting their turn to take a bath on their day off from the trenches 744

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caring for her thou- sands of wounded in beds made of palm leaves. Above is shown a wagon train of these on the way to Cairo DISEASE IS MORE DANGEROUS THAN BULLETS 4 OREM GS terse CAs p This is not a giant searchlight, but a mobile disinfecting plant for clothing. The appa- ratus is a vital neces- sity in ver- min - rid- den Galicia and Russia © International Film Service, Austro-German troops are forbidden melistiefcers. The inane. to drink water from wells and springs not tested by ws a water distilling plant belonging to the Austrians 745

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INVENTIONS DEVELOPED IN THE WAR A clever French method of quick-firing when a machine gun is lacking. A half dozen ordinary rifles are put together in a box, and by means of a rod connection every rifle may <e ovat at the -— a. Con- ee ee | siderable speed may be de- il - . ee veloped by this method, as the more quickly the wire is pulled, the more quickly the shots are fired. This invention is defec- tive. When the device has been fired five times the clips are all emptied and the guns must be loaded, with consequent loss of time, perhaps at a moment when time is the most precious of commodities @ American Press Association. A bomb-throwing cannon in the French trenches. The tiny cannon throws the bomb, filled with high-explosive powder, into the opposing lines. The wings attached to the bomb impart a whirling movement to the projectile, and keep it on a true course, so that the percussion cap on fhe tip js certain to strike the ground, thus setting off the charge 746

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WRITING HOME FROM A DUGOUT The battlefields of the Gallipoli peninsula will probably furnish pages of history unequalled for blood and horror by any known before. Part of that history is being written today from the dugouts and bomb-proofs of the Allied lines, where British soldiers from the shores of all the seven seas gain their only respite from their battles with the Turk 747 it. ' { i | { |

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INGENIOUS EXPEDIENTS IN FIGHTING A machine-gun adapted by the Germans for anti-aircraft work. It is held in a special support, so that one man feeds cartridges, another pulls the trigger, and operated by three men, as here shown. Great accu- racy can hardly be obtained with this weapon ; H + onal i ot ont © International Film Service, French artillerymen lowering ammuni- tion in the Vosges Mountains. This am- munition is carried from the motor trucks to the firing line in artillery lim- bers. In the rugged Vosges it is often found necessary to slide the shells down the sides of the mountains, as shown here, while the difficulties of transport- ing guns tax the ingenuity of the artil- lerymen and engineers. Small pieces and machine guns are carried over the mountains strapped to the backs of mules, while the larger field artillery is lowered down the mountains on skids An isigenious mounting for a French mitrailleuse, or rapid-fire gun. By mounting the gun on a cart-wheel, with a barrel filled with stones for a base, this improvised anti-aircraft gun may be easily swung to follow the flight of aeroplanes, however fast they may go 748

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THE HAVOC OF GREAT GUNS The explosion of a German 150-millimeter shell near a French 155-millimeter rapid-fire gun. Only one member of the French gun crew has remained at his post, for the gun has been charged and sighted and needs only to be fired, which may be done by one man. The rest are in the bomb-proof under the bushes ~*~ , oe, inal {2 Mew ema a As il a tm i we\ee . SEN A Sees cm Si. fo Russian 30.5 centimeter guns were broken like glass by German shells. The delicate breech mechanism may be easily destroyed by a shell which explodes near the guns, but in order to wreck a heavy gun as completely as are those shown in the illustration, it is necessary to hit the gun squarely with a projectile of heavy calibre

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THE THORNY SIDE OF VICTORY Photos © Brown & Dawson The roads through the battle-scarred districts of Russian Poland are full of these Austrian entanglements, invariably erected after a victory, to act as a check against counter-attacks. (Below) Austrians erecting a barricade in a forest. The soldiers are seen hewing the limbs of trees into fence posts and barriers, across which the barbed wire is stretched 750

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WHAT ENGINEERS ARE DOING IN THE WAR @ International Film Service. A ventilator in a German trench. So we see that a even the ventilating en- gineer is used in war. When the French captured this trench they found the officers’ huts supplied with fresh air by means of the blower shown © International Film Service. One of the enormous guns used in the war. A twelve-inch Italian howitzer near the Austrian front.' These great guns must be supported by concrete—real civil engineering work. The transportation of such a “field piece” to its position was in itself a work which an old-time army quartermaster could hardly have handled 751

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The priceless statues and monu- ments of Venice have been encased in a heavy overcoat of plaster, surrounded with canvas, in order to protect them against injury by Austrian. aeroplane attacks. The shells of the Italian anti-aircraft guns often fall in the cities which they are defending, and constitute nearly as grave a danger as do the bombs thrown by the enemy. The stairway of the ducal palace is an arsenal—of sand bags! That these precautions were well timed was demonstrated the latter part of October, when Austrian aeroplanes visited Venice and showered bombs upon the city. One bomb fell in the piazetta in front of St. Mark’s, not far from these very mummy-statues. The damage which they might have suffered can be guessed when their age is considered, and one remem- bers that the Campanille crumbled to dust one fine day a few years ago, with not even a gentle Italian earth- quake to start its disintegration. These statues are very old, and con- cussion nearby might well be as disastrous as a shell exploding on their heads. ITALY ARMORS HER STATUES AGAINST AIRCRAFT — ? =. “3 ‘ ads oy ots | ee 3 * ee 3 se BAY fae ‘ * e ee “2 uhh Ss The horses of St. Mark’s have been taken from their historic pedestal and have taken their way to underground caverns where they, at least, will be safe from attack, even though the city and St. Mark’s itself shall fall The statuary of St. Mark's has all been removed or else swathed in plaster and many coats of canvas. Gentle precautions, these, against modern explosives, but they would save the statues from destruction by concussion from explosions 752

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THE EARS OF PARIS LISTENING FOR AIRCRAFT By Courtesy of Illustrated London News The most interesting of the special instruments employed for the defense of Paris against aerial attack are the “‘listening posts," one of which is shown in the illustration. This consists of four huge horns, which gather up the slightest sound and magnify it by means of a microphone, so that it is impossible for an aeroplane to approach unheard. The horns resemble reversed megaphones

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THE HIGHEST DAM IN THE WORLD The great Arrowrock Dam, the highest structure of its kind in the world, was recently added to the completed projects of the Reclamation Service. This great irrigation project covers an area of two hundred and forty-three thousand acres, not far from Boise, Idaho. The dam is two hundred and sixty-one feet high, eleven hundred feet long. 754

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CLIMBING A MOUNTAIN ON A ROPE These aerial rope-railways are usually employed in mining districts for transporting ore from the mines to the ore-cars. But, near Bozen, Austria, a rope-railway is used for pas- senger trafic. Passengers are taken a part of the way to the summit of the Kohlerer Mountain on these swinging cars 755

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HOW IT WAS DONE A THOUSAND YEARS AGO This water lift, still in use on the River Tigris, near Bagdad, is one of the most ancient mechanical contrivances in existence. Inclined uprights, which are lashed together with rope, are fixed near the water's edge, and project above the bank, or over a brick wall, as is the case in the illustration.’ Rude buckets of hide are suspended by ropes wound on a wooden windlass operated by crudely-applied hand power

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE _ 1517 sco ba NN 0 ARE EE SARE SITIO LOR OT SMR Mee Ti eae These peach pits are the remains of many breakfast dishes of dried peaches Here Are Tons of Peach Pits It would be enough to make a house- wife shudder to think of paring all the peaches from which came the pile of pits shown here. As a matter of fact they were not pared by hand, but were dried with the skins on and packed by a pack- ing-house at Corning, Calif., and sent East in car lots. The pits weigh many tons and represent about as great a weight of well-dried fruit for winter use in the East. More Efficient Coal Mining Three quarters of a million men were employed in the coal-mining industry in the United States in 1914, according to C. E. Lesher, of the United States Geo- logical Survey. Although the average number of days worked in the bitumin- ous mines was the smallest since 1896, except only 1908, and the average out- put per man for the year was the lowest in five years, the average daily produc- tion by each employee in 1914 was the highest on record in bituminous coal mining. This record is to be attributed not so much to the better character of the labor as to improved mining methods and the increased application of scientific management. In the bituminous mines the yearly average decreased from eight hundred and thirty-seven tons in 1913 to seven hundred and twenty-four tons in 1914. The daily average increased from three and sixty-one hundredths to three and seventy-one hundredths tons. The aver- age yearly production of anthracite by each employee decreased from five hun- dred and twenty short tons in 1913 to five hundred and five tons in 1914, owing to the fewer days worked. The daily output per man was two and six hun- dredths tons, a slight gain as compared with two and two hundredths tons in 1913. A Chance for Motor Boat Makers The American Consul at Bermuda reports that that island presents a fairly good market for detachable rowboat motors. It is estimated that there are now about thirty detachable motors in use in the colony, all of American make. These were purchased during the last five years, and it is estimated that under normal conditions it might be expected that from five to ten of these motors could be sold every year. This is one of the markets for American products which will open when the war is over.

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758 Speeding Up the Loading of Motor Trucks With the increasing speeding-up of deliveries due to the motor truck, there has been a demand for a mechanical loader which would fill the truck in less time than is possible with hand shovels. An electric motor loader which will dig and load sand, POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE body was hoisted from the chassis and set on a standard slightly higher than the chassis of the truck. Then the machine backed under the loaded body, which was quickly dropped and secured to the truck. This method.saved much time, as the truck did not have to remain idle while the lumber was being loaded. broken stone, and gravel at the rate of one cubic-yard a minute has recent- ly been invented. The apparatus is supported upona wheeled truck, and is easily moved by two laborers. Twenty steel buck- ets, each having a capacity of one- half a cubic foot of material, are mov- wy A New Govern- ment Grain Sampler Specialists of the United States De- partment of Agri- culture have pro- duced a new and simple device for sampling grain, seeds and _ other material. Its pur- pose is to secure a reliable sample from a larger por- ed on a belt by an electric motor de- veloping ten horse power. The same idea lies at the bottom of another scheme for increasing the effi- ciency of the motor-truck—this time the tradesman’s delivery truck. A large Boston lumber wholesaler has found that by the use of interchangeable bodies, he could greatly speed up the de- liveries of his lumber by motor truck. Two bodies were made for Electricity does the work of hundreds of shovels tion of the material to beexamined than would be pos- sible under the old conditions. The principle is the distribution by gravity, of the material to be sampled over a cone which is provided with separate ducts in a way to insure the thorough mixture of the grain. This does away with the destructive method of digging out samples at different points in a pile. each truck, and while the machine was making deliv- eries with one of the bodies, the duplicate body was being loaded. Upon the return of the truck to the yard, the truck was run to a platform, the : Removable truck bodies are not uncommon now that the power is within the truck and not in horses which can be unhitched Duplicate bodies are made for each chassis. While the truck is making deliveries with one, the other is being loaded, in order to take the place of the empty body 3

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This flounder changes his spots to suit his surroundings The Masquerades of Fish Protective coloration among the fishes has occupied the attention of scientists for centuries. Dr. Sumner, of the United States Bureau of Fisheries, recently made experiments with flounders at the famous aquarium at Naples, Italy. He found that these fish are able to make themselves inconspicuous against almost any back- ground, and, unlike the leopard, can change their spots whenever they choose. Not only were these particular floun- ders able to adapt themselves to the color of the background, but to the pattern and the texture as well. They assumed a very dark shade upon a black bottom and a very pale one on a white-bottom. They took on one pattern for sandy bottom, and another one for fine gravel, and still a third when the bottom was covered with small stones. Variously painted glass strips were prepared and laid down for the fish to practice upon. Some were done in draught- -board pattern and others in white “polka-dots” on a black ground. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE em Pe so eee @#@oee 4 ines Be occccccee. \oeeeeece tee A fish that did his best to look like polka dots 759 The fish did remarkably well consider- ing that some of the patterns were pre- viously unknown in their little circle of life. Their splotches of black, white, gray and brown approximated the pattern so well that very careful study was often necessary to trace the exact outline of the fish. It was also proved that the flounder has individuality that, in some cases, at least, is capable of cultivation. Some of the fishes have much greater power of adaptation than others. Certain of them acquire with practice the power of chang- ing more rapidly than at first. The time necessary for a complete change of pat- tern or shade ranges from a few seconds to days. This tree held a mountain sheep till he died and then grew around its horns A Forest Tragedy Two hunters, wandering through the dense forest along the boundary line be- tween Northwestern Montana and Idaho, were surprised to see protruding from the trunk of a lofty white pine tree at an elevation of twelve feet from the ground, a large pair of Rocky Mountain sheep antlers firmly imbedded in the living tree. They carefully cut down the pine and removed the section containing the ant- lers. They found that the skull was im- bedded in the trunk at a point where the diameter is twenty inches. They reached the conclusion that the right antler had been caught on the base of the tree when the pine was about nine inches in di- ameter. Thus the animal was made a prisoner, and, being unable to escape, per- ished. The length of the larger antler is twenty-six inches. It is in perfect con- dition, having apparently been protected by the foliage of the tree. By counting the rings, the tree was estimated to be one hundred years old.

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760 The wooden fence may rot, but the concrete base lasts and is used for a new post Concrete Fence Post Bases A new detachable post-base, invented by Alvin Z. Pierce, Woodhull, New York, puts life into aged fence posts. The crumbling of old posts at the base and - toppling over is overcome by the detach- able bases, which are of concrete and consequently not subject to decay. The bases are reinforced by vertical rods im- bedded in the concrete, and also have wires in the concrete and extending across the longitudinal channels of the post bases to provide means for fasten- ing the posts to the concrete. In a modified form of the invention metal angle plates which serve as post anchors replace the concrete base. No Signboard Like This The effect of a huge signboard with- out. the disfigurement of his property by The sign actually makes the house more attractive POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE an ordinary painted board was secured by a Los Angeles house owner by using his terraced lawn as the background for the words “FOR SALE,” the big letters being formed separately and secured to the sod by pegs. The result is more strik- ing than conventional, requires only a small part of the material used on a sign- board of corresponding dimensions, and is by no means as unsightly as a painted announcement. ‘*Magnet Bill’’ He doesn’t look like a very important part of a big automobile organization, this stooped, grizzled man, but the president of a great motor-car company says that “Magnet Bill” saves his salary a dozen times over every day he works. Rain or shine, summer or winter, “Magnet Bill” may be seen walking slowly about the automobile plant, his eyes on _ the ground. “Magnet sill” gets his nick- name from the fact that his tools con- sist solely of one tin bucket and a big steel magnet strapped to the end of a shovel handle. It is his duty to save automobile tires by removing from the roadway every nail and bit of metal that might cause a puncture. Thousands of cars are run over the road- way to the testing place, and it is figured that without the precaution taken by “Magnet Bill” the cost for cut and punc- tured tires would be twenty thousand dollars every year. He prevents a hun- dred punctures a day Clodomiro Figneroa, the Chilean avia- tor who made several attempts last year to fly over the Andes, has announced that he will resume his attempts in the near future. The airman follows the route of the Trans-Andean railway. from the Chil- ean side.

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Hub Step for Wagons The handiest place for a wagon step is on the _ hub. But until such a step was patented by Joseph A. Butcher, of Dallas, Texas, the idea was never. thor- oughly applied. His step, which extends over the hub, is cast on a sleeve which. slips over and is fastened to the nut of the wagon axle. This sleeve is cut to fit snugly over the nut and is kept from turning by the edges of the nut over which it fits. An overhanging portion of the sleeve which passes over the end Here is a hub step that is practicable of the nut locks it in place and prevents - the nut from working loose—a result of considerable importance, for it eliminates the use of set screws and inconvenient fastening devices. The idea, simple though it may appear from a glance at the illustration, has been the subject of more thought than might be at first supposed. Engineers of sev- eral of the large vehicle companies worked for several years with the idea of providing a hub step for wagons and had abandoned it as impractical, resort- ing instead to the rather dangerous sub- stitute of corrugating the hub of the front wheels to afford a foothold for the driver entering and leaving a_ vehicle. Stepping on the ordinary hub is a dan- gerous procedure, though it is frequent- ly done. Every State Makes Clay Products It is an interesting fact, not widely known, that clay products are made in every state of the Union, although in the territories, Alaska and Hawaii, have re- ported none. Last year’s production was valued at one hundred and sixty-four million, nine hundred and_ eighty-six thousand, nine hundred and eighty-three dollars. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Clock Made of Stove Repairs A Philadelphia stove maker has con- structed a “grandfather’s clock” of the waste materials of his factory. This clock stands eight feet high and is thirty- four inches wide. The dial, of mica, is eight inches across. The words “Stove Repairs” compose twelve letters, used in place of figures on the dial, which is il- luminated from behind by an electric light. The hands are of eighteen gauge wire. The base of the clock is composed of grates for ranges, and the center of the front is inlaid with fire- bricks. In the cen- ter of the brick panel is a three-bar grate, representing the trade-mark of the maker. The main body of the clock above the base is composed of grates for ranges on the front and fire-plates on each side. Nickel knobs outline the door, and a nickel panel represents the window for the pendulum. The space surrounding © the face is con- | structed of brack- ets of top end shelves of cook stoves, and an an eight-inch pipe collar forms the frame for the dial. The columns on both sides of the body are of four-inch black stove pipe that rests on water backs, and four- inch pipe collars add a finish to the ends of the columns. The words appearing at the top of the clock are made of nickel damper knobs. A waterback hole, covers for ranges and stove rods help to finish off the space around the letters. Hinge caps form a bead around the edges. Slip plates for ranges, in which flue-stops are inserted, finish the sides of the top. Five urns are mounted on the summit. The total weight of the structure is about three hundred and fifty pounds. It looks like a stove but it is a clock

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wn oe 762 Giant Valves for Water Power Plant Two hydraulic valves, believed to be the largest ever constructed, have been erected at Salt Lake City for a hydro- electric plant, which supplies lighting and power current. Each of the valves weighs more than ninety tons. An idea of their immense size can be gained by a comparison with the pigmy-like figure of a man standing beside one of them. Their internal dia- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Germans Furnish French with Excel- lent Bomb Throwers One of the newest French bomb throw- ers is as simple as the brass guns that smal! boys delight to play with. It con- sists of a German shrapnel shell case mounted on a wooden stand, with a spike in front to anchor it firmly to the ground. The case of the shrapnel remains intact after it has been fired, as its object is meter is twelve feet. These valves are a radical departure in some ways. The valve usually em- ployed is known as the sliding gate type, but this: new type is operated on a plung- er principle. A huge plunger, which tapers to a point, fits in a thick steel casing. The plunger works auto- matically, feeding more water to the turbine as the pressure de- creases, and holding back when the pres- sure increases. Encased in its cylinder, the valve has an ‘over-all length of over twenty-three feet. Each of the turbines to which the giant valves will deliver water has an electrical output of ten thousand horse- power. They are driven by water with a head of one hundred and forty feet. Horses and mules to the number of 436,760 were shipped to Europe and Canada during the twelve months begin- ning with August, 1914. These immense valves con- trol the flow of the water into great hydraulic tur- bines and prevent their being flooded. Their con- trol is automatic, being co- ordinated with the speed of the generators which they ee to act like a small can- non; its end opens and the shrapnel with which it is filled is driven out by a charge of powder at the bottom of the case. These shell cases are carefully picked up by the French to be used against the enemy. They are cut down, and a touch- hole is bored in them. The cost of the finished bomb thrower is but little over a dollar. To use them, a charge of powder is poured into the shell case, and a bomb, well loaded with explosives, is placed upon it. The charge is fired by the touch-hole, and the bomb is thrown into the air. It turns clumsily over and over like a large sausage, but it finds its tar- get with remarkable accuracy.

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Walls Are Built Like a Floor Building a house wall like a floor and then tilting it to an upright position is an original system of construction which has been so perfected that at present it is used for large and costly concrete structures, saving time and material. Walls up to one hun- dred and twenty feet long have been raised by this method, and many of the structures built by the Federal Government such as bar- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE _ 763 needed by this method, as the upper sur- face requires no forms. This upper sur- face (when the wall is horizontal) is the outer surface of the wall when it is set upright, consequently all the disfiguring board marks are on the inner surface, which receives plaster or other interior finish. The smooth sur- facing of a concrete wall is diffi- cult and costly, but by this method it is readily ac- complished, for the fin- ishing coat and all dec- racks, mili- The walls are built of concrete on the ground and then orative fea- tary hospi- tals, cavalry stables and other military buildings of standard .type, which have long but not high walls, were erected by this system.. In building an edifice by this method, the foundations are laid and within them a series of steel-trussed frames is set up in perfect alignment. The frames are placed a few feet above ground, in an almost horizontal position, and they are set a few feet apart and at right angles to the foundation. These frames carry the wall, so that after the concrete has had time to cure the supports are brought into an upright position, setting the wall squarely upon its foundation. raised to their places in the completed house tures can be added while the concrete is wet, in which condition the adhesion is perfect. This is one of the most advantageous features of the system. A Bridge Made of Scrap Iron Carrying an important highway over the Calumet river not far from Chicago is this unusual bridge made from steel scrap salvaged from other structures. The character of the material is shown to every passerby by the empty rivet holes, which are visible in the photo- graph in the top of the conical plate serv- The raising is done by tele- scope screws of unusual length, one under each steel frame. The jackscrews are operated simultaneously by a worm gear which turns all of them at an equal rate, the motive power being a small engine. The tilting is very gradual and the wall comes into position without any jar or shock. There are many advan- This simple bridge was made from scrapped structural steel tagess in this system. In the first place the forms are laid flat upon the steel frames, not built in an upright posi- tion, and the work of placing the forms is done in less time. About half the lum- ber used on other forms is all that is ing as abutment walls to hold the high- way fill and in the angles bracing the truss. The curved braces between the piers at the center of the stream are old railroad rails.

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764 Making Push Carts of Truck Bodies to Save Time and Money A highly efficient loading system for trucks has been developed by a Los An- geles wholesale grocer, who finds it a great saver of time and truck drivers’ salaries. Hours wasted in loading are both actual cash outlay and loss of capital return on the investment in vehicles. The waiting time at the warehouse is reduced from half an hour or even a full hour, to ten or fifteen minutes, by an equipment of extra bodies for the motor trucks and an overhead rail system, which carries these bodies through the warehouse at a rapid rate. Even the design of the bodies is original, each consisting of two interchangeable units, which are furnished with steel hooks so that they can be lifted bodily from the chassis. Each unit is in reality a hand truck, as it is furnished with castors so that it can be pushed for short distances. When a truck has finished a morning delivery to retailers, it returns empty to the warehouse and the driver makes his report to the office. Meanwhile the two parts of the empty truck body are lifted from their place by means of the over- head system and instantly replaced by two loaded units, with the contents ar- ranged for systematic delivery and prop- erly checked up. This means no loss of POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE time on the driver’s part. He is ready for the second delivery at once. The empty bodies are handled, in- side of the warehouse, like the usual hand trucks, and they are loaded for the truck’s delivery with one action of the workmen. For instance, the body unit is sent to one part of the building for a hundred pounds of sugar, to another for a drum of coffee or case of corn. Prob- ably some of the goods ordered are on an upper floor, and in that case the ela- borate conveyor system carries the body unit into a freight elevator, which is furnished with an overhead rail, and on the next story the device is switched up- on the conveyer system of that story. Very little pushing about by hand is re- quired. Finally the loaded unit is sent to the loading platform to await an empty truck, on whose arrival it is set upon the chassis in five minutes, the sec- ond loaded unit is placed beside it and the truck is ready to make deliveries. It is easy to see that the number of trucks is reduced by a system which keeps them busy all the time, so that the in- terest on the investment in machines is saved. Another point is that confusion of the loading platform is eliminated, and goods can be checked carefully, avoiding mistakes and loss. Each of the carriers for the overhead system is in charge of one man, who rides beside the motor and controls it. An overhead rail sys- tem and interchange- able bodies reduce the waiting time of a mo- tor truck from half an hour to ten minutes. The bodies are fitted with castors and over- head cable pulleys, so that they can be wheel- ed through. stock rooms to receive their loads

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An Electric Piano Player Controlled by The Moving Picture Operator The electric piano player shown in the illustration makes possible the instan- taneous change from one piece of music to another at any moment and is par- ticularly adapted for playing pianos in moving-picture theaters. By means of endless perforated rolls, the operator of the lantern can instantly change the type and tempo of the music from the rear of the house, without any other attention to the piano. Bellows are eliminated by a series of electrical points which actu- ate hammers that play on the keys of the piano. The musical program embraces thunderous music for battle scenes, fast, snappy music to accompany animated scenes, such as horse or automobile rac- ing; pathetic music for heart-rending scenes, and so on down the gamut of human POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 765 Repairing an Aeroplane Under Fire a Mile in the Air The thrilling story of an Australian air pilot who was strung by one hand to the framework of a disabled aeroplane five thousand feet over the enemy’s lines while executing repairs with the other, was told by an officer observer from Northern France. “We had crossed the German lines and their guns were booming at us from way down below when Cornstock (the pilot) noticed our left wing was tilting down and not responding to the controls,” said the officer. “He swung out of the seat to the right side, but the plane con- tinued to tilt, and it looked as if we were going over sure. “Cornstock let himself down with nothing but thousands of feet beneath him, holding tight with his right hand and f um bling e m otions. And all are under the instant control of the op- erator in the lantern booth. Thus, the wrong music at the wrong time is av o ided; while the appropri- ate music is supplied at the will of the op- erator, who is best withthe control wires where they were jatmmed under the body of the ma- chine. 2 oe strain on his right arm must have been terrific. Seconds seemed hours as he swayed there, his legs dang- ling in able to eo judge the aes ‘ the m a- require- chine ments of swung the scene. over ‘air The _ play- bumps’ er-piano 1s and lever- a “prop- ed to the erty’’ at side. As a picture This electric piano, with endless perforated rolls, is controlled feat, it was theaters. from the operator's booth superb.”

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766 When the new army filter bag has stood for ten minutes, the water may be drawn off through spigots Our Army’s New Water Works Through an ingenious invention of Major W. J. Lyster, U. S. A., typhoid fever and other sicknesses caused by drinking impure water are practically banished from the army now by the use of a very simple sterilizer. This wonderful invention, which now gives regiments of soldiers an abundance of pure water by a quick conversion of the impure water, consists of a hemp bag and a very small quantity of hypo- chlorite of calcium. These hemp bags are large enough to hold 40 gallons of water into which is mixed 1 ‘gram, or 15% grains, of calcium hypochlorite. The bag is sus- pended from a tree, or a tripod, if no trees are handy, and allowed to stand for ten minutes. At the end of that time the water in the bag may be drawn off through spigots at the end of the bag and used for drinking with perfect safety. The hypochlorite of calcium kills all dangerous germs, both animal and vegetable, in the impure water and POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE no boiling is necessary to render it sterile. Each bag is twenty inches in diameter and twenty-eight inches long. Not only is the new invention a great advantage for the army, but the method of purifying water quickly and effective- ly with a small bit of calcium hypo- chlorite lends itself admirably to private use. New Crank Lock for Light Automobiles Holding the starting crank in a rigid upright position, preventing unauthor- ized use of the car, and in addition pro- viding a logical place for the front li- cense number, are the advantages of a new crank lock, especially suited for Ford cars. As will be seen from the illustration, the device is simplicity it- self. It consists of a bracket, slipped over the cranking handle with a forked upper end, through the holes of which a Yale lock is put. A flat steel spring holds lock and fork against the crank- ing handle, preventing its rattling and forcing the fork back against the radia- tor when the lock is removed. The lower end of the device is arranged so as to take the license number, which is thus removed from all interference with the water cooling of the radiator. In hot summer days it has been discovered that the license number, if placed direct- ly in front of the _ radiator, keeps the air currents from the cooling cells, with the result that the motor is over- heated. When the lock is engaged, the crank is fixed in position

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Shipping Live Fish Carrying live fish from the Great Lakes to the cities of the Atlantic sea- board and the Middle West has brought the delicacy of carp and “whitefish” to epicures quite outside the former limits of the lake fish “belt.” This has been made possible by means of a regular system of delivery in tanks of fresh water by express. The arrange- ment of the express tank-car is interest- ing. A narrow aisle runs down the cen- ter, and on both sides range large metal tanks with heavy metal covers. A laby- rinth of pipes and ventilators hangs above. Within these tanks, ten in num- ber, swim some three thousand live carp, perfectly at home, for the tanks are filled POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Three thousand live carp ride in railway car tanks, filled with Lake Erie water with Lake Erie water. Ten thousand pounds of live fish ride to market in a single car. It would hardly do to throw the fish into the water-filled tanks in Sandusky, Ohio (most of them are shipped from there), and expect them to be fresh and well after a journey to the Atlantic sea- board. The water would soon grow stale and the fish die. A system of aerat- ing the contents of the tanks was, there- fore, necessary. When the train is in motion it was easy enough. As passen- ger coaches are lighted by electricity gen- erated on their own axles, so the live-fish car gets its power from the axles to force air into its water tanks. But when the enginé stops and the tank-car stands still for a space of time even so short as three minutes., a little Pintsch gas engine un- ted 767 derneath the tank-car is busy driving the air-pumps. The water is kept in a con- stant state of fomentation during all stops. Were the aeration process to cease for a few minutes the death rate of the finny cargo would take a leap. The transportation of live fish is a delicate matter. Careful handling begins long before this, however. It began back in San- dusky harbor the very moment the carp are caught. There is a science in han- dling live fish for overland transporta- tion trade. Designers have constructed special “carp-cars,” a sort of wooden crib that floats in the water, full of caught fish. Whole trains of them string by the shores of shallow Sandusky Bay, a throb- bing “locomotive” (a motor dory) haul- ing them to the packing piers, where the tank-cars are awaiting their loads. A “Carp Car” with special fences to prevent the loss of flopping fish Each “car” has a capacity’of nearly a thousand fish, and is twenty-eight feet long, seven feet wide and thirty-two inches deep, with three-foot rail fences lined with canvas on top to prevent the lively, flopping carp from escaping back into the lake. With the special “carp-cars” or the like and the tank express cars, the loss of fish amounts to only one per cent. A Prop for Capsizing Cars Some of the French military motor trucks have been equipped with rods which swing out to arrest the tilting when the truck threatens to capsize on a badly crowned road. This tilting ten- dency is immediately arrested by the feet on the ends of the rods, as these prop the car up as it starts to fall.

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768 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

War Eliminates the Rotary Motor One of the mechanical features of the European War has been the unexpected failure of the rotary type aviation motor and the triumph of the fixed cylinder en- gine. The result of a year of the most strenuous work that aeronautical motors have ever undergone is that the rotary motor is already in disfavor in Europe, and the fixed engine is supreme. Most readers will remember the sweep which the famous Gnome rotary motor made of American flying exhibitions and contests a few years ago. motor conditions. Everyone was ready The rotary triumphed in the days when _ to believe that the aviation motor was ex- flights were of comparatively short dura- tremely delicate, but they were surprised tion and the great cost of operation to learn that the average life of two counted little, and when intricate mechan- prominent makes of rotary motors was ism was‘no drawback because there was four and twelve hours, respectively. Sev- always a large force of skilled mechan- eral hundreds of a certain rotary motor icians to make repairs and adjustments. averaged but four hours’ actual service. Under war conditions, faults come to One of the chief defects of the rotary light. Flying corps were composed of motor is its extraordinary oil consump- men who had only average mechanical tion. One of the most important Euro- knowledge. If there were repairs, they pean motors of this type has an oil con- had to be made by the flyers themselves, sumption which is thirty per cent. of its often under fire. The failure of the gasoline consumption. A __ successful motor meant capture, often death. Flights water-cooled motor of the stationary were of a longer duration, and heavier type has an oil consumption of only loads had to be carried, and all sorts of fifty-seven hundredths of its gasoline weather had to be encountered. consumption. Under peace conditions it was difficult Although the rotary motor is famous to get all the facts in regard to actual for its lightness, figures show that under flying conditions it is really heavier than the stationary motor. <A rotary engine of two hundred horsepower will weigh about six hundred and sixty-three pounds, while a fixed-cylinder machine weighs about one thousand and ninety-nine pounds. This seems to give the rotary a great advantage, but when the tanks are filled for a flight the advantage swings the other way. For a flight of ten hours the rotary engine weighs two thousand eight hundred and forty-one pounds, while its rival, with the fixed cylinders, weighs but two thousand two hundred and three pounds. In warfare, where it is often __ necessary tO carry great The Gyro 90-horsepower motor, a popular American weights, this saving in fuel is engine used on flying machines very important.

The eight-cylinder, 160-horse- power Curtiss, one of the best of the American aviation motors

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Mechanical Playthings of Today POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE By A. M. Jungmann A steam engine furnishes the driving power for a small electric motor. rotates a shaft which drives many different toy lathes, grinders, pumps and jig saws, making, in its entirety, a ONE is the little tin soldier who bravely entered the ranks at Christmas only to disappear, mortally wounded, by New Year’s Day. And gone with him is the doll with the sweet china face and wig that would not stay on; gone, also, are the impossible build- ing blocks that built delightfully impos- sible structures which were never seen on land or sea. The watchword of to- day in toyland is education. And to attain that end we must have lasting toys. For what child can learn the prin- ciples of anything from a toy that is broken in a week? And so, instead of the gallant but weak tin soldier with his useless gun, we have unbreakable sol- diers and guns that really shoot in quite i" 7 } 4 = GREER K pa VE This, in turn, miniature machine shop as businesslike but not as dangerous a manner as do those which are devas- tating Europe this minute. The sweetly pretty doll with the lovely but silly and breakable china face has yielded suprem- acy to the unbreakable character doll. Prettiness will not auswer any more un less it means something. The building blocks that built castles, whose only architect was the imagination of child hood, have given way to construction toys which duplicate accurately all the structural work fathers and uncles risk life and limb to accomplish. The original purpose of toys, which is to amuse, has not proven sufficient to the American child. Toys which merely amused were cast aside in so short a The skyscraper express elevator is operated by dropping marbles. One marble causes the car to descend and the counterweight to ascend. To the right is a sand crane. As soon as the crane receives its load, it dumps the sand opposite the loading point; then the crane returns

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FASHIONED BUILDING BLOCKS GIVE PLACE A large walking engine. The boy builder learns how a walking operates when he makes this toy. The motive power is sand which runs out of a hopper and falls on a ‘paddle wheel. The paddle wheel imparts movement to the con- necting rod of the walking beam, which transmits power to the welding hammer connected with the other end of the structure A mechanical mill made easy to construct. It demonstrates the principle of the regula- tion type of farm windmill. The bladed wheel at the top is connected with the grinding wheel at the bottom by means of a string belt. An electric fan whirls the mill around very realistically An inclined railway built up of small girders. This model is fashioned after the inclined street railroads in operation at Pittsburg, near the Pittsburg and Erie : a, Railroad. The cars descend by their own weight. They can be lifted by means | 4 ‘A : of a motor or by hand. The pulleys at the bottom beneath the power house are | * é f > seis mounted on shafts over which the cables are run. The two ends of the cable e 3 are attached to the two cars A bridge constructed from the same parts as the walking beam en- gine and windmill at the top of the page. This bridge is five feet ten and a half inches long and fifteen inches : high

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TO CONSTRUCTION TOYS THAT EDUCATE A working Ferris wheel built of pinned QQ blocks. Note the P complete detail of the construc- The remarkable feature of this Semi - Bungalow made from locked blocks is that the house _ has flooring in - the rooms. The bungalow is as completely fin- ished on the in- side as it is on the outside 4 tion, even to the * little toll gate The pins hold the trolley car together, yet may be drawn out very read- ily so that the blocks may be used to con- © ~ struct other els A ‘traveling derrick, d A fleet which may be made oY of battleships which from pinned blocks. Because of the may be taken apart and put to- key-seated lock used on the gether by any child. This toy is driving wheels, this crane wwe designed to familiarize the child with will pick up a big load / ¥ sales - the construction of a battleship and to for its size gee i teach him the names of its various parts. As the fleet consists of both battleships and cruisers, he is taught to distinguish the types of fighting ships A contractor’s ele- vator made from pinned blocks. This model will hoist materials as readily as a real contractor’s ele- vator. The eleva- tor may be picked up and moved from one place to another clipper ship, an ocean liner or a A full - rigged | battleship can be | put together with equal ease. The equipment is | complete down to the flags

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ENGINEERING STRUCTURES REPRODUCED IN MINIATURE 1) | i YL ee Oe oe Acircular saw built by a clever Amer- ican boy who won a prize with this model. The saw is operated by motor. The boy thought out all the mechan- ical details himself Page +, - ” se ewer ‘_ A dock crane built of the same parts as the sight-seeing tower on this page. Variable racking is obtained by a jib-adjusting motion. The spindle gear alters the rise of the jib. Equipped with two hoisting drums this crane will lift two loads at once = ™} This is a construction toy which resembles a 44; structural steel work. The girders are made i ~=—sjust like real girders used in construction work. ; | wilt Ann ae - This is an exact replica of the type of bridge used where river traffic would be hamp- ered by a swing or lift bridge. The suspended carriage is operated by motor They are so strong that they will bear the ; weight of an ordinary boy /\ sheave in A construction toy designed to teach the principles of mechanical engineering to a boy. The material employed consists of perforated steel strips, plates, angles, pulleys, gears, brackets, axles, cranks, as well as a screw-driver, screws and nuts. The boy can make any num- ber of working models with this outfit Sight-seeing tower which rises to a height of five and » The cage is operated =- 2 by acord which is led ~. from the motor to a the dome, a half feet.

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GAMES AND TOYS WHICH AMUSE BECAUSE THEY ARE ALIVE Brooklyn boys conceived the idea of nailing roller skate wheels on a long board on top of which they fastened a wooden box. By standing on | the board and © propelling themselves by one foot they managed to derive much amusement. This toy is the Brooklyn boys’ idea _ cleverly carried out. A doll-wheel-toy. Amusing and durable. When pushed (= y* ~ or pulled the figure has a, \\ ‘ realistic action as though hey AS ‘y were operating a hand car. ) con The movements of the body// // and car cause the bell to ring\\ / a ne “% PO A miniature operative talking machine. not easy to get it out of order These vehicles are operated by clock work to run seventy-five feet. The toys may be made to travel in a straight line or by turning the front /)/wheels they may be made’ to de- {! scribe a circle. The hook and ladder | fis particularly clever. When wound up it will travel toward the building be “ ego oe ar a The “Speedway.” The track rests on a pivot and the motive power for cars is obtained by a slight rocking motion of the board. The cars will race around the track as fast as eighty laps a minute. Each car can be controlled by the person operating the toy supposed to burning and on touching it the ladders automat- ically raise them- selves against the object It is carefully con- structed, the appearance is pleasing, the records clear and it is When a string is tied to the toy and it is drawn along, the revolution of the front wheel causes the doll to pedal. B it is ted on a pivot, the doll sways from side to side while it pedals and has the life-like motion of a small boy on a velocipede

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HOW THE WAR IS REFLECTED IN TOYS pressed. A. toy field piece which shoots soft rubber balls as rapidly as a lever can be de- taken apart and reassem- bled. This is a perfectly safe military toy. The sol- diers to the right are knocked over by the gun ——2> gun can be A very realistic toy machine- gun is modeled after a mod- ern rapid-fire military gun that shoots one hundred and eighty thousand times without stop- ping. The barrel is of wood, smoothly bored. The ammuni- tion consists of wooden bullets. The velocity of this gun is not great enough to make it unsafe fietad A fifty-shot pistol repeater, which han- dles roll caps. It is like a real repeater 4 This warship is modeled after the Torpedo Boat Destroyer “Decatur,” U.S. N. It is 36 inches in length. It has low- built upper works, four oblong smokestacks, two turrets, five rapid- fire guns and two deck torpedo tubes. It carries a lifeboat hanging on davits which may be turned to swing full offboard. The torpedo will travel at a speed of four miles This realistic toy is actually operated in water. The bat- tleship floats until the tor- pedo strikes the target, which releases a spring; the battleship opens in the cen- ter, fills with water and sinks. The torpedo is wound up and then released. If well directed it will hit the motive power is supplied by an electric motor. c by a dry cell battery target. The battleship, after the encounter, may be taken out of the water and held in a vertical position until all the water in it has run out of the portholes of the lower end; then it can be snapped together and is ready for the next encounter

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PRACTICAL USES OF ELECTRICITY REFLECTED IN TOYS craft For the little girl who wants to play house here is an electric stove that really cooks. There is no danger of fire, yet the childcan bake, This electric motor boat is exactly like the motor boats used as pleasure vice which ? A toy which teaches a boy wireless. When in operation this toy sounds pre- cisely like a wireless station when mes- sages are being flashed through the air The cars have boil or fry food This is a telephone de- start electric trains. The child simply speaks into the telephone and or- ders his train to stop. It will work on either al- ternating or direct cur- rent They are faithful models of real automobiles. wheels have rubber tires and the cars carry a spare tire in the rear. in the track bed. They also have a flexible front shoe for guiding on it A submarine designed from a photograph of an American submarine built in the Brooklyn Navy Yard. This boat measures twenty-eight inches in length. It may be submerged so only one quarter of it can be seen above water. It will run four knots an ho’ d rams anything in its way. The motive power is furnished by an electric motor om alla will stop or Above: An ingenious and simple toy which teaches a children something about é 2 the elements of the tele- . ie ad Ir ™ phone Below: Toy which will enable a boy to learn =~ al telegraphing } woe «« ~~ = J Sl Tetesram 5] Electric trains and motors teach boys to become familiar with electricity as motive power. The roofs of the cars are remov- able. The boy may make figures of men and women and put them in the cars. The locomotives are made of steel ‘a Automobiles operated by electricity. The rear shoe for collecting current from insulated rail

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776 time that it seemed that their mission was not fulfilled. The restless spirit of the age extends to the children. In or- der to hold the attention of the chil- dren toys must have a _ purpose. soon as this fact was borne in upon our toymakers they began turning out toys which were designed to make the child think and learn at the same time they were amusing him. The great success of the construction toys indicates that toys with a purpose are a childhood necessity. ; As this is a mechanical age it is only 1atural that the toys we make for our children should be, in a very large measure, mechanical. Children have al- ways loved to see the wheels go ’round, but nowadays they want to know why. To meet this growing demand many of the mechanical toys are so constructed that the child can take them apart, examine the mechanism, and put them together again. This means that the construction must be simple and the ma- terial strong. A child who shows an aptitude for mechanics subconsciously absorbs an understanding of mechanical principles while he is playing with his toys. That children are naturally destruc- tive would seem to be controverted by the enthusiasm with which they have welcomed the construction toys. They appear to take quite as much delight in constructing things out of these new toys as they did in break- ing the old- time ones. The child with an incli- nation for As.’ POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE engineering, or for any sort of struc- tural work, may find toys with which he can build anything from a _ wind- mill to a railroad bridge, from a crane to an elevator, The great merit of these construction toys is that the child can make working models from them. If the child happens to see a crane which attracts his attention he can go home and build one like it and op- erate it by electricity, too, if he so de- sires, for the better construction toys are capable of developing models which may be so operated. All the great construction work that has made these United States famous for their engineers finds its miniature counterpart in toydom. A toy railroad, for example, is not built after the toy- maker’s idea of a railroad. The loco- motives, the cars, the switches are all faithfully copied from locomotives, cars and switches actually in use on one of the great railroads of the country. If a railroad brings out a new style of car it is only a matter of a very short time before a miniature of that car will be found running over the rails of a toy railroad. All this attention to detail is The child gets to know the educational. Boys of sanlag are no longer eoutent with the impossible building-blocks of other days. They want to build Ferris wheels, aeroplanes, cranes and trucks

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE With this set of parts, this boy has made an accurate flying model of the German Taube and American Curtiss. On the table in front of him will be seen a partially completed model of the small racer designed by Cecil Peoli, a model which holds the world’s record different types of railroad equipment, he recognizes the cars when he sees them in actual service, he learns the signal sys- tems and becomes familiar with the con- struction of a railroad and the principles of transportation. The same thing is true of toy boats. From a sailing vessel to a battleship the toy boats are copied in every detail from boats engaged in the business of life. Like other toys of to-day boats may be taken apart and put together by their small owners. This gives them the op- portunity to learn the principles of ma- rine architecture. The growing demand for educational toys has led the toymakers of the United States to bend their energies toward the construction of this particular class of toy. Before the present European war broke out there were toy factories in twenty-three of the States. Since then the number has greatly increased. For a time it was generally believed that the war would cripple the toy trade in Ger- many, and many persons in this coun- try rushed into the business of making toys. As might have been expected many of these manufacturers through lack of capital or experience found them- selves unable to compete with the older houses and were forced to drop out. On the other hand, a large number of them have been successful, and are turning out toys which make a distinct appeal to the American child. The war has had the effect of stimulating the toy trade in the United States, but it can- not be said to have caused the creation of a new industry. Many of the best toys made in this country are not made by concerns which are given over exclusively to the manu- facture of articles for the amusement of children. A manufacturer of stove bolts makes toy vehicles which are favorites with the children ; some of the large pub- lishing houses put out quantities of toy books; and a manufacturer who makes agricultural implements is also a manu- facturer of toys. This peculiar condi tion makes it difficult to obtain an ex- act idea of the scope of the toy industry in the United States. The American public spends about $40,000,000 a year on playthings for

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778 > children. More than half of this sum goes for toys made in this country. New York State leads in the number of toy manufacturers, although there are numbers of toy factories in many of the other States. After New York comes Pennsylvania, with Ohio a close third in the toy industry. Next to the educational feature of the new toys is durability. There appears to be a veritable craze to attach the word unbreakable to the modern toy. From the man who sells dolls in the street and demonstrates their unbreakable quality by beating the sidewalk with the dolls heads to the exclusive retailer who is too polite to adopt such direct methods, all sellers of toys endeavor to impress upon the purchaser that their toys will not break. The mechanical toys are gener- ally made so they may be safely taken apart and put together again. It is not longer necessary to sacrifice the toy to An automobile built with the same parts which compose the sewing machine shown at the top of this page gratify the child’s curiosity. Where the toy is of such a nature that it is impos- sible to permit this the mechanism is pro- tected by heavy casing made of steel or iron which is designed to stand anything short of the blows of a pile driver. The war has had an effect on the type of toys which might be described as martial. There are many new war toys which have come into being in the past few months. Beginning at the top there are dirigibles, monoplanes, bipianes, hy- droplanes; then getting down to earth and sea, there are rapid-fire guns, mili- tary automobiles, military equipment of all sorts, regiments of unbreakable. sol- diers who may be mowed down by ma- chine guns; _ battleships, lastly, submarines. But with all their excellence and their harmlessness, military toys will never have the vogue that the construction toys have because the peace-at-any-price cruisers, and, POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Seeeeaene A sewing machine—the kind of toy which the modern child builds out of special parts party will have none of them. There are numbers of people who think it nothing short of criminal to put a toy suggest- ting warfare into the hands of a child. It is significant of the tendency of the times that the toys represent practically ev- erything in mechanical engi- neering, in electrical and con- struction problems, but the agricultural toy is conspicuous by its absence. Our children may play at being wireless op- erators, at sinking battleships with tor- pedoes, at running a great railroad, but not at plowing a field. The raised and lowered by means of a motor and erptied by pulling a cord. This is one of the latest operative construction toys A revolving steam shovel. bucket is

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A Union Life Suit One of the most novel life preservers yet offered to the public is the invention of O. A. Youngren, of Sheridan, Wyo- ming. Before a large gathering of prom- inent steamship men, Mr. Youngren re- cently donned his life saving union suit, dived into New York harbor, and dis- ported in the chilly water until he had demonstrated the device to the complete satisfaction of the spectators. The union suit, which comprises the life pre- server, is made of water- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 779 Motor-Driven Coastwise Schooner Shipbuilders on the Great Lakes have devised a type of ship which they claim will dominate the coastwise trade and displace both the modern coal steamer and the great schooners which carry so much of our coal. This type is a steel-built, five-masted schooner, with a full spread of sail and also a powerful oil engine, so that it will be able to make fair speed in almost any sort of weather and save towage costs, proof material, and is |, weighted at the feet with five-pound lead shot. This tends to bring the wearer into an upright position in the water. The buoyancy of the suit comes from a life belt of a special composition which lashes about the waist and over the shoulders. The entire device, ready for the water, weighs about fifteen pounds. GA = oS Blowing himself up which amount to thousands of dollars yearly for big ves- sels. These auxiliary five-masters will be of about three thou- sand tons, fit for off- shore as well as coastwise business. They are believed to be the most econom ical craft yet devised for general freight- ing. Our exports of cotton yarn to Ar- gentina during May, June and Julyof this This life-saving union suit keeps clothes dry and also rescues the It is weighted at the bottom to keep the body upright, and is held up by life belts at waist and shoulders wearer from a watery grave. year were nearly ten times as much as for the entire year 1914.

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> amtiraehapenae re EWSPAPER accounts of Henry Ford’s plans for building a light farm tractor have stirred popular imagination to the point of picturing an immediate development as. start- ling as that of the justly famous Ford car. However, it is doubtful that Mr. Ford entertains any such visionary ideas as the writers who are so thoughtfully interpreting his plans to ‘the public. Until the fruit of his experi- That Small Farm Tractor of Ford’s and the auto are built to carry; the trac- tor is built to pull. The load which helps to establish traction in one case is de tached in the other, and upsets the paral- lel completely. Taking round-wheel tractors as a class, four pounds of weight are required to overcome one pound of load resistance as measured by the dynamometer. A twelve- inch plow, cutting only six inches deep mental work is put upon the market we can safely refrain from passing judgment upon his product. Whether or not the tractor which is now being described and pictured can be established on the typical Ford scale 1s, however, worth a thought in passing. That section of the agricultural press which spe- cializes on farm power ma- chinery expresses its doubt in no uncertain terms, basing its opinion on an amazing proces- sion of well designed small a Farmers are looking forward eagerly to the time when this experimental | tractor of Ford's will be marketed in the mellow loam of the Middle West, may have a draft as low as two hundred and fifty pounds, but is more apt to run three hundred and fifty to four hundred pounds. Two plows may easily over- come the ground - gripping This Ford tractor is, not yet on sale, yet it is the best advertised tractor in the world tractors which have failed to fit economi- cally into the farm scheme. The conditions to be met are severe. The popular imagination which sees a light tractor as successful as a light motor car overlooks many vital factors. From the light car to the light tractor is a far greater step than from the auto- mobile to the motor truck. The truck TRO power of a tractor weighing three thousand five hundred to four thousand pounds under very favorable circumstances. It is not so much a question of motor power as of ability to deliver a fair pro- portion of that power at the drawbar. This mechanical problem is aggravated by the unfavorable surfaces over which the tractor must often travel—soft, rough, stony, and with frequent sharp changes in grade. The motor car has momentum to help it over the bad spots

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in the road; the plow behind the tractor is a dead load. The automobile works at its maximum for short distances only ; the tractor is normally loaded nearly to its limit. The light car is justified largely on the score of pleasure and convenience. The tractor must pay a profit. The sale of a large quantity of light tractors at a low figure has already proved an easy matter. Some very good models, me- chanically spe: aking, have been put out by reputable concerns of long experi- ence in this field. But from an economic standpoint not one can be regarded as a distinguished success. Individuals, rather than a large class, have made them pay. There is seemingly no logical parallel between the light motor car and the light tractor. Whether Mr. Ford will succeed in establishing one remains open to doubt. It will be well not to credit him with either success or failure until the farming public is invited to assist in the demonstration. Hiding a Torpedo Boat With Stripes Many photographs have come from Iurope showing ships, automobiles and guns painted with spots and splashes of many colors. When one is near these objects their vari-colored paint gives them a weird appearance, but when “they are seen at a considerable distance the splashes of primary colors fade into the landscape or seascape and render them almost invisible. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 781 Abbott Thayer, a prominent American artist, has devoted many years to a study of the colors of animals. He claims that each animal is colored by nature to protect itself against its own particular enemy. The zebra’s coat is designed to confuse the enemy most dangerous to the zebra. Working on these same lines Mr. Thayer says that it is a great mistake to paint our battleships a plain gray. Although the war paint is much more sttitable than the white paint used before the Spanish-American War, even the gray color is visible at a great distance. To prove his point the artist obtained permission from the War Department to paint the torpedo boat destroyer Patter- son according to his ideas. The illus- tration shows the result. Long, wavy lines on the gray war paint attract much attention when the slim ship is close at hand, but when she steams away from the observer she suddenly seems to dis- appear, as the wavy lines blend per- fectly with the ripples and waves on the surface of the ocean. Up the Rockies in High Gear The publicity department of a prom- inent automobile concern announces that in the early spring, one of their twelve- cylinder cars al start on a transconti- nental trip with all gears removed except high and reverse. It will have to cross the “Rockies,” drive through mud and start from a dead stop—all on “high.” E ow ao An artist, who is an expert on the coloration of animals, designed this scheme for conceal- ing a torpedo boat on the surface of the water. ripples of the sea, and the boat is lost to sight At a distance, the stripes melt into the

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ee placed. On the arrival of the party, he made a few remarks about the fatal results of fin- gering the wires. His visitors were so much impressed that it is said they kept their hands in their pockets until they were safely outdoors again. Death in Five-Sixteenths of an Inch An English mechanic, em ployed in an aeroplane fac- tory which is turning out fly- Maud, the Motor Mule, can dance on her hind legs and spin in time to music The Antics of Maud, the Motor Mule An automobile that will run on its “hind legs,” spin about, buck, and per- form generally like the trick horse or mule of the circus has been the star fea- ture of a number of race meets held in widely separated parts of the country. The car is known as “Maud, the Motor Mule.” “Maud’s” athletic and adventurous talents are due to a heavy weight hung over her tail and to individual brakes on each rear wheel. The weight is heavy enough to overbalance the car. It runs easily on a little track projecting over the axle, and is concealed beneath a hous- ing. The driver controls the position of the weight by means of a lever and is thus able to make the car buck as he wants it to. When the car is reared on two wheels one of the independent brakes may be applied and one of the wheels locked, causing the car to spin around on that wheel. The band usually plays a waltz for this, and the driver, Roy Repp, man ages to keep in time with the music. A Skeleton Danger Signal The manager of an electrical plant, who was expecting to show a party of friends through the station, decided to avoid possible accidents by an unfor- gettable warning. _He borrowed a skele- ton from a friend, a surgeon, and placed it before the switchboard, where it would be the first thing to be seen. Above the grinning head a huge “Danger” sign was ing machines for the British Government, was arrested and fined for wilfully cutting the propeller of an aeroplane five sixteenths of an inch shorter than the standard length. It was alleged that he had done this act because of spite, since the firm would not release him for work elsewhere. It was stated that the life of an aviator would have been endangered if the defect had not been discovered. A serious shortage in hardware goods has been reported from Sydney, Aus- tralia. No one who passed this switchboard forgot the warning against handling wires or open switches

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 783 The Motorcycle as a Cart Horse When the projectile is released from the aeroplane, it will glide down swiftly. The That the motorcycle has fields of op- course of the missile is easy to follow, portunity yet unthought of was proved’ even at night, for in the stern is a large by a test to which one of them was oot electric light which will be constantly in Owatonna, Minn., recent- ly. An expressman, whose horse was sick, appealed to The motorcycle makes a very satisfactory cart horse in an emergency the manager of a motorcycle agency, and the latter, w ishing to acquire some publicity, offered the use of a motorcycle as a cart horse. A stock model machine was hitched between the shaft and hauled the express wagon to and from the different railroad stations with no trouble what- ever. A Wirelessly Controlled Aerial Torpedo A wirelessly controlled aero- plane torpedo, which may be dis- charged from an aeroplane and guided in its flight by a radio- instrument in the flying machine or on the ground, is the recent invention of George F. Russell, of East Orange, N. J. This aerial torpedo differs from most others which have been invented or suggested in that there is no motor by which it may be propelled, and that it must be launched from a height and left to glide to its target by means of its aeroplane wings. The torpedo is made of alu- minum and weighs but two hun- dred pounds. The model is seven feet and two inches long, twelve inches thick at the head, and five inches at the stern. It weighs but fifty pounds without the explosive. visible to the sender. A small governor is controlled by a mechanism in the forward compartment of the torpedo, and prevents the discharge of the explosive until it has gone several hundred feet on its downward flight. After that, it will discharge at the slight- est contact. Dozens of patents have been taken out on wirelessly con- trolled aerial torpedoes but not one of them is in use. An aerial torpedo which can be-actually controlled in its flight by wireless from an aeroplane or from the ground. The torpedo weighs two hundred pounds and is made of aluminum. It is exploded on contact with a solid object

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POPULAK SCIENCE MONTHLY AND WORLD’S ADVANCE nia, for Southern Cali- fornia is the home of original methods of ad- vertising real estate. Letters two feet in height, six inches in thick- ness and a foot wide, which form the name of the tract upon which they were located, were cast The lines and workmanship of a racing boat were incorpo- rated into the making of this automobile A Motor Car with a Boat Body One of the most freakish cars ever seen in New York has recently been dis- played in an automobile manufacturer’s show-window. The body resembles a modern motor boat and is built of alter- nate strips of mahogany and white holly, while the deck is finished in bird’s-eye maple. All the deck and body fittings are finished in nickel, and the upholstery is of pigskin. On the rear portion of the circular radiator is a silver eagle with outstretched wings, while forward of this is a ship’s bell, also finished in silver. The entire body is harmonious, and the resemblance to a watercraft is truly re- markable. The strange body was fitted to a stock chassis, and is occasionally driven on the street, never failing to at- tract much attention. Cement Makes’ a Solid Advertisement A novel use for cement was made in building the culvert sign shown in the A concrete real estate sign can be ornamental as well as indestructible photograph. This stationary advertiser is located upon a tract of land a short distance north of Los Angeles, Califor and so placed as to form a support for the railing which ran across the en- tire width of the culvert. This culvert, containing the street name, is situated on a main state highway. With the excep- tion of the railing running across the top the culvert is finished in rubble effect, while the railing, which is six inches thick and a foot wide, is finished smoothly. One Man Handles a Thousand-Pound Hogshead A hand-truck newly invented, by Ben- jamin V. Harvey and Basil K. Watkins, Danville, Virginia, has made it possible for one man to load and transport heavy hogsheads. The man shown in_ the By ingeniously-applying the principle of the lever it is possible for one man to handle one thousand-pound hogsheads with this truck illustration is taking up a hogshead of tobacco weighing one thousand pounds. The most difficult part of the work, which is the loading, is made possible by the provision of longitudinal runners extend- ing out to the end of the truck, the rounded ends of which afford an effec- tive leverage. At the same time the hook which extends over the top of the truck has its point engaging the further side of the hogshead to prevent it from rolling off.

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ROPERTY own- P ers along certain sections of our Atlan- tic coast are wisely realizing that-it is well nigh useless to try to battle with stormy seas. This is particu- larly the case on the New Jersey coast reaching southward from Sandy Hook for scores of miles. Many thousands of dollars have been spent in years past in building bulkheads or in run- ning jetties out from the shore to arrest the destructive wash of storm -tossed break- ers. but almost with- The storm-swept cottages out exception the Ocean has had its way in the Cottages built on the crest just above the beach line have been repeatedly undermined, and this abandonment or the bodily retreat of the buildings. This situation has stimulated the business of the house mover, but it has also developed phases of the craft not commonly met. unusual thing the country over to see frame houses shifted from one site long run. meant either surf has played havoc with ocean-front Moving Houses to Escape Ocean Breakers By Robert G. Skerrett Moving a large house on a _ pontoon across a stretch of open water to another, but, as a rule, these transfers are matters of only a short distance and, generally, the struc- tures are of modest dimensions. The house mover on the peninsula south of Sandy Hook has had harder tasks _ than these to battle with, and the transplanting of the cottages has not been _ confined alone to overland journeys. Indeed, some of these build- ings—the very biggest of them—have had to make water trips in order to reach their new Iccations, and , this sort of voyaging has taxed the utmost. front Atlantic It is no hay. 785 cunning cf the house mover to the Some of the cottagers have moved their summer homes hundreds of feet north or south beyond these low areas while shifting back from the ocean as .well. ownersarecrossing the Shrews- bury River, and planting their houses land far above the reach of the highest tide. The wiser property anew on the main- Another house being transported across the (Center) Wreckage caused by autumn storms

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mune teen nies See SOU At LORS CAN AE NGRIEE WORE 786 Sixty-Million-Candlepower Searchlight A new motor truck equipped with a searchlight developing sixty million can- dle power, has recently been adopted by the Italian Government. The search- light itself is equipped with a small car- riage fitted with wheels and rollers, so that it may easily be dismounted and operated at a distance from the POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE producing capacity of this concern is two hundred and fifty artificial legs a month, and it is planned to have its output multi- plied five times in the near future. How Strong is the Rope? The question of whether the rope will stand the strain can now be answered motor car that furnishes the power. The searchlight has a glass parabolic mirror fitted to a frame which may be easily removed. It is artificially cooled by a small electric fan, this guaranteeing a long life to the silvered surface of the mirror. A blind signal device is fitted to the front of the searchlight, so that the light may be used for signaling at This new army searchlight develops sixty million great distances. When the iris is shut in front of the light the plant is invisible at night at only a few yards distance, even with the searchlight working within at full power. The Booming Cork Leg Industry An industry which has been practically dormant in the past but which is now growing by leaps and bounds is the man- ufacture of false arms and legs. One American concern is said to have re- ceived already orders from the French and English Governments to the extent of fifteen million dollars. The normal candlepower before the accident occurs, and is doing much to prevent unfortunate mishaps to men who risk their lives on scaffolds, tall chimneys, mines and elevator shafts. Through the perfection of a rope-test- ing machine precisely how much strain a rope will stand can be accurately recorded. The tester is motor driven, and carries the rope over a series of grooved pulleys while the pressure is ap- plied by hand power working through pulley and gears. No matter how long the rope may be, the same tension is ap- plied to every inch of it, thoroughly testing it for re- liability. The tension as applied to the rope is indicated by a scale located near the opera- tor. As the material under test passes from the pulleys it is caught and wound upon a reel ready to be removed and tagged. The rope is in no way weakened and its ability to come up to its full specifications is determined by its actually doing so. The test of rope for strain will not, however, affect the life of a rope of steel or The strength of the rope is accurately ascertained inch by hemp which must end a day inch by putting it to the test of an actual strain before it wears out.

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This Adjustable Table Makes Home Exercise Convenient It was Dr. S. Weir Mitchell, the great Philadelphia nerve specialist and author, who first pointed out the vast possibilities for effective exercise which were con- tained in an ordinary library table and An _adjust- able table has vast pos 8 i- bilities for effective ex- ercise Straps for the legs and _shan- dles, permit healt h- ful exer- cising two feather pillows. His patients were taught the principles of exercise at home on the table in Dr. Mitchell’s office, and many traced their rejuvenated nerves very largely to the formulas of exercise which he taught them. The superinten- dent of a middle western sanitarium has devised an adaptation of Dr. Mitchell’s scheme, in a table which is adjustable to all angles and is fitted with addi- tional appliances. The table in its natural posi- tion affords opportunity for leg lifting, trunk exercise and many other forms of physical train- ing. Through the adjustment of the supports the table may be converted into an inclined plane for other forms of exercise. Straps across the table be- neath which the feet may be thrust, two handles at a conveni- ent position on either side, and a cord with a handle are some of POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 787 the simple additions to the table which render it extremely valuable for the work for which it was designed. Spin the Table to Get Salt and Pepper A dining room table with a revolving center and with the extension leaves of segment form adapted to latch together, has been invented by two Washing- ton men. The extension leaves are held in rigid position by four arms ex- tending from the central supporting post of the table. A turn of the lock- By means of collapsi- ble legs the table may be convert- ed into an inclined plane ing lever fastens together one of these arms and the corresponding bracket which supports the ex- tended leaf. The central portion of the table has a depending stud which fits in a pocket in the central post, and the table is made easily revolvable by sup- porting it on ball bearers in a race beneath the table. To pass the salt on this table, it is only necessary to give the revolving cen- teffpiece a spin half around to bring an article from across the table to a point directly in front of the person who wants it. Meanwhile ‘the segmented leaves or cuter portion of the table remains stationary. Two hundred and fifty million dol- lars were spent on state highways last year. This unusual table has a revolving center and segment leaves latched together

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Motion Photography at Night in In- accessible Places For some time motion picture direc- tors have felt the need of some apparatus that would enable them to utilize for night photography locations that are so far from the source of’ electric power as to make it impracticable to stretch wires for lighting purposes. This prob- lem has recently been solved by Romaine Fielding, formerly a “movie” star and now feature director of one of the large 4 companies. He has devised an indepen- dent travelling power plant that will make possible night motion photography in many inaccessible places where arti- ficial light has hitherto been unknown. The portable thirty-five horse-power plant, which was constructed in accord- ance with Mr. Fielding’s ideas and is his own personal property, besides providing apparatus for running wires, is equipped with a powerful twelve-inch navy search- light of the projector type. This light is mounted on the seat beside the driver and may be operated either while the car is moving or standing still, The capacity, of the searchlight is four and a half million candle power. When in operation it requires twenty-five per cent of the full power of the plant. Mr. Fielding is staging pictttres in the Grand Canyon of Arizona, and with this pow- t erful searchlight expects to delve into { the depths of the caverns of the great Pt crevasse and to utilize for locations the ' dark recesses, caves and trails. This will be the first time that the marvellous- ly beautiful scenery of the canyon has it served as a nocturnal setting for the pic- tured drama. This portable plant makes possible night mo- tion picture photography in spots to which electric light wires cannot be strung 788 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Through Jonah’s Gateway Gates have been made of many mate- rials, but the one shown here was con- structed from the jawbones of a whale. The jawbones, which bend inward at the Enter and pass, Jonah-like, through the jaws of a whale top, pass through two concrete blocks, and are then sunk six feet in the ground as well. Hence they are almost thirty feet long. This entrance to an estate in St. Johns, Newfoundland, has been in use for over seventy years, and is still in perfect con- dition. Stray Steers Cause Discovery of Cinna- bar Deposits Two prospectors, trailing some stray steers in western Nevada, found that the tracks led over an old prospect in which a face of red mineral was exposed. One of the men recognized the mineral as cin- nabar. Returning to the spot a few days later, the two miners spent ten days and 7 located seventeen claims. When they re- turned to the town of Mina, Nev., and made known their find, nearly every man in the village rushed to the spot and staked off claims. It is from cinnabar that mercury or “quicksilver” is ob- tained, and the field thus discovered is likely to be profitable.

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Kitchen Cabinet Can Be Adjusted in Height to Suit the Worker A kitchen cabinet has recently been per- fected, which can be changed to the cor- rect height for either the very tall or the very short woman. A simple turn of a crank, placed conveniently at the right POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE A simple turn of the crank raises or lowers the kitchen cabinet to suit the short or tall housewife hand corner, will raise or lower it to the correct height. The top of the cabinet base telescopes the lower part as the table is lowered, and a ratchet holds it in the proper place. There are additional novel features about the cabinet, among which are the sliding doors in the upper section. These doors may be opened and closed without removing any articles from the table top. The sugar jar is equipped with an automatic valve, which opens with the pressure of a cup, and closes when the pressure is released. The coffee dispen- ser at the left of the sugar jar has a sliding compartment underneath, which enables one to obtain a heaping table- spoon of coffee at a time, thus measuring it without the aid of a spoon. The two long shelves, the full width of the cab- inet, are an especially economic ar- rangement, as most cabinets have narrow ‘divided shelves. 789 Germany Wants American Feature Films A report recently issued by the Amert- can Association of Commerce and Trade in Berlin states that notwithstanding the war, the improvement in motion picture film production has steadily been pro- gressing, and that the German film to- day is in every sense much better than before the war. A poll among a large number of leading members of the Ger- man film industry indicates that the American film is well liked, although lit- tle information can be gained in Ger- many as to the American feature film. The report states that there should be a big field in Germany for a progressive producer of features if he should secure an experienced representative in Berlin and furnish him with a negative film to secure prompt deliveries of positives. The association invites American pro- ducers to avail themselves of the serv- ices of that body in securing proper representation. How Uncle Sam Shears His Horses The accompanying photograph shows how Uncle Sam employs mechanical means for clipping horses. It must be remembered that these patient, hard-worked animals are required to look as neat and trim as their masters; and the picture shows a trooper at Fort Thomas, Ohio, shearing his horse with the aid of a pneumatic device, in which the air is compressed by turning the handle of the apparatus. Rapid and neat work is assured by this device, and the operator is not so quickly fatigued as with the old hand shears. Clipping an army horse with air

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or CORT FOE HE 790 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE The Electric Mule Unlike the Missouri mule which was never known to have but one speed, and that sometimes backward, the electric mule has six speeds, four ahead and two reverse. It is built in three and four wheeled types. It has steel framework and solid rubber tires on its wheels. It varies in weight from two to eight tons. The new electric mule can handle a dozen or more of the old-style four- wheeled trucks if they are equipped with couplings and links so they may be hooked up to the tractor. When this the sound of the cannon was heard at Laibach, an Austrian city some fifty miles distant. A very sensitive seismo- graph in the station for registering earth- quakes at Laibach traced a record of the shaking of the ground from the batteries in action during the second battle of Gorz on the Isonzo. The chief of this earthquake-station, a school-inspector named Belar, pro- posed to the military authorities as long ago as 1907 to make experiments in re- cording the vibrations caused by the fir- ing during the summer artillery practice. An electric draught animal does the work of from fifteen’ to fifty men vehicle and its train are in motion the driver sits either forward or stands on the rear step. On the great wharves of New Orleans, Savannah and Galveston, it is no longer an uncommon sight to see a storage bat- tery tractor hauling a train of ten or twelve trailer cars all loaded with cotton. The modern electric mule does the work of from fifteen to fifty men. While the trailer decks are being loaded the tractor is usually employed hauling other trail- ers, which are ready for trains, from the railroad terminals to the docks and some- times even into the holds of transatlantic steamers. Earthquakes Caused by Big Guns Among the interesting scientific sug- gestions that the war has called forth is the proposal to use the seismograph, an instrument for recording earthquake-vi- brations, as a registering apparatus for studying the vibrations caused by ar- tillery firing. During the recent fighting between Italy and Austria on the Isonzo, a river flowing into the Gulf of Trieste, Seismographs were placed at different distances from the ordnance and the tracings they made were compared. A perceptible contrast was noticed be- tween the line made by the firing of can- non and that arising from the discharge of mortars. The vibration resulting from the recoil-after the firing of cannon made a line of short waves; the explosion of a shell produced a longitudinal wave- movement. Professor Belar has sought to make a collection of tracings sufficiently large to establish a table of reference from which, he believes, a large amount of information about cannon heard at a dis- tance could be deduced, including the direction, number and calibre of the guns, and whether friend or foe was firing. An interesting point proved by his trac- ings is that the recoil of a gun-barrel produces a vibration scarcely less than that arising from the recoil of the old gun-carriage.

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1 ow TF 1 To re re m »t le in ld To Help Autoists Out or Ruts Automobile tourists and drivers of long-haul motor trucks will find joy and relief in a new and simple device for enabling a vehicle to pull out of a rut —— ~~ \ Fastening Tl hong Fastening thongs are secured to the spokes and canvas tape is drawn under the wheel, thus presenting a firm, dry surface for the tire to ride upon. Thus the autoist is helped out of ruts or a mud-hole on its own power. Where- as formerly the driver of a ditched autc- mobile was confronted with the annoy- ing necessity of running to the nearest barn for a plank or a pole with which to extricate his car from a mud-hole, the new device is so small and compact that automobilists can carry the means of their deliverance right under the running board of the car. A glance at the illustration shows how essentially simple this new accessory is. A strong tape of very tough texture, pre- ferably of canvas or fiber paper, and of a width slightly exceeding that of. the tires, is wound upon a reel contained in a small metal case fastened beneath the running board. Attached to the free end of the tape, which may be of any desired suitable length, say fifteen yards, are two stout leather thongs or cords strong and flexible enough to be tied and untied many times. With this device the motorist who might otherwise find the pleasures of a tour marred by a mud-hole or a rut can easily liberate his car. The two thongs are drawn out, fastened securely to a spoke of the imprisoned wheel and the power applied. As the canvas or fiber tape is thereby gradually drawn under the wheel, a firm, dry surface is pre- sented to the tire, which grips the tape and easily emerges from the rut. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 791 Showering Gifts from the Sky A feat in advertising was recently performed at Atlantic City, N. J. An aeroplane flew over the crowded board walk, and dropped boxes of cigarettes on the heads of the promenaders. Listening to Birds’ Table Talk On the lawn of an English country house, the cats never permitted robins and finches to gather up the crumbs thrown by the little chap in the picture. Accordingly, the lad’s father erected a cat-proof tray on a tall pole, and added to the tray an ordinary telephone trans- mitter protected by a brightly painted tin can. When the hungry birds gathered for a feast on this tray, their chirping and singing were plainly carried to a receiver located in the house. salle 7 i When hungry birds gather in the tray, their chirping is carried by telephone to a distant house

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792 Agricultural Clubs for Boys and Girls There has been an increase of more than forty-one thousand in the member- ship of various boys’ and girls’ agricul- tural clubs conducted by the State Agri- cultural Colleges and the Department of Agriculture in the northern and western states. At the close of the last fiscal year, there were one hundred and ten thousand and seventy-seven members in the various club projects in the thirty- three states covered by this work. At the POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE The Home Electrical and Practica) One of the features of the Panama- Pacific International Exposition which had a popularity surprising even to its producers was the “Home Electrical.” 4 California stucco bungalow was built with- in one of the greatexhibition buildings, In the attractive surroundings of home, the newest electrical appliances which have been produced to make modern house- keeping easy were laid out. Here the visitor learned all the nice- tiesof electric table cookery, the pleasures . _ of electric heating, the inestimable con- veniences of the electric kitchen, and the marvels of the electric laundry. Our 1914 Stone ‘‘Crop’’ During the year 1914, the income from the sale of stone quarried in the United States exceeded that of any year prior to 1912. The total was seventy- seven million, four hundred and twelve Ground plan of the Electric Home at the Panama-Pacific International Exposition close of the last fiscal year, the member- ship reached the huge total of one hun- dred and fifty-one thousand, one hun- dred and ninety-four. Members have their attention direct- ed to problems of farm and home man- agement, crop rotation, soil building, etc., and a large number of club members are now working out three and four-year rotations of crops. The profits which they derive from club work they are spending on getting an education, or for purchase of pure-bred stock and labor- saving machinery. Many are even buy- ing land. eo sé erarenane thousand, two hundred and ninety-two dollars, a falling off of a few. per cent, from the income of the two previous years. The sale of granite made up more than a fourth of the total. Monumental stones represented only one-tenth, the remainder being divided among sand stone, paving stone, curbstone and mis- cellany. Pennsylvania out-distanced all other states, as it has in every previous year, except 1908.

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THE HOME ELECTRICAL AND PRACTICAL #8: : eS The sootless, electric kitchen. The rosy grate and indirect light, electric comforts of the modern living-room (upper right-hand corner). The breakfasts of an ever-increasing pro- portion of Americans are now made feasts of daintiness by the magic of electric table cookery (center). More drudgery has been eliminated by the electrical home laundry (lower cut) than by any other scientific achievement 793

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- HE use of proper clothing to prevent in- jury is a phase of the “Safety First” Cam- paign that is being vigor- ously pushed by the Na- tional Found- ers’ Associa- tion in an en- deavor to cut down the number of acci- dents occurring in foundries. Much attention is paid to the clothing which should be worn by the molten met- al workers who are in constant danger of being splashed by the fiery liquid which they handle. In “many foundries, burns of the feet and legs have been almost completely eliminated by the use of proper clothing. Heavy shoes, leggings of stout eer The sand- blast worker wears a _ respirator Leather gloves are part of the equipment of the men handling hot or raw cast metal in the modern foundry Gloves and sleeve rings are important canvas and woolen trousers, turned down at the bottom, form an admirable combi- nation. For severe heat conditions around fur- naces and ovens, furnacemen often re- quire gloves for their hands and arms. Calfskin or buckskin gloves usually answer the purpose, but in some cases asbestos must be used. Injury to the eyes of foundry em- 794 Appliances and Clothing Protect Workmen ployees, caused by the splashing of metal or the flying of chips in cleaning and grinding operations, are frequently se- verte, often resulting in partial or even total blindness. Safety goggles have caused a marked diminution of injuries to the eye, in shops where they are worn by all employees while engaged in han- dling molten metal. Men who handle pig iron, scrap and rough or hot castings are greatly ben- efited by suitable hand leathers or gloves. A form of hand leather that has proved quite acceptable is composed of two Goggles and leather boots in molten metal work pieces of heavy leather cut to the gen- eral shape of the hand and fastened to- gether at the wrist by elastic goring sim- ilar to that used in foun- dry shoes. The dangers encountered in dusty occupa- tions, unless carefully pro- vided against, may injurious- ly affect the health of em- ployees en- gaged in such work. In many instances the employees do not realize the Helmets are now used in heavy sand-blast work co ————————

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pontine nooo pager ery dangers and the necessity of preserving their health, and accordingly they do not take advantage of the safety devices provided by their employers for their protection. Helmets and respirators are usually furnished for the use of sand blasters, but they are too often disre- garded by the workmen. Unless the helmets are used and the respirators kept moist, the men run grave danger of POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 1795 son, Charles Weyman and William Thaw. The detachment has, beside the aeroplanes, a number of motor cars and trucks, motorcycles and a staff of me- chanics. All of these are operated by Americans, most of whom were living on the Continent when the war broke out. It is said that several members Bf the American Ambulance have joined the new flying corps. These Hens Must Exer- cise for a Drink A prominent poultry- man in Tecoma, Ne- vada, has devised an un- usual set of elevated water fountains which require the poultry to fly up to them to satisfy their thirst. This gives them the needed exercise to keep them well and to Non-inflammable clothing is used in work contracting lung trouble of an especially serious and chronic nature. Emphasis is placed by the association upon the need of keeping the clothing in good repair, so that loose belts, torn gloves, dangling sleeves and other pieces of clothing do not catch in the machinery. Many injuries caused by contact of mov- ing machinery with finger rings worn by mechanics have been reported. Such rings should not be worn by workmen where a hazard of this kind exists. The workmen are being constantly re- minded that the cautious way of doing their work is the safe way, and that safety appliances not only protect them but also serve to render their work easier and their labor more efficient. American Aviators with French Army An aero corps composed entirely of American aviators is now at work with the French Army. For several months the corps has been practicing at Pau, and by this time is probably in actual service at the front. Some of the well-known Americans composing the corps are Norman Prince, Elliot Cowden, James Bach, Frazier Cur- tis, H. G. Guerin, Burt Hall, Didier Ma- make them lay well. The conical cups from which they drink are narrow and sufficiently raised above the platform or perch so that the hens cannot climb in and foul the water. The rapidity with which the hens learn to use it is remark- able. Running water is constantly supplied to the various fountains by pipes which are laid underground. An elevated loop in the pipe keeps the water in the foun- tains at a uniform level, and in the win- ter warm water is used, so that there is no danger of fire from the use of water fountain lamps. near furnaces The hens have to use their wings when they want a drink

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796 A New Way of Sharpening Used Safety Razor Blades The unsatisfactory character of the edges of resharpened safety razor blades is a source of annoyance to home shavers. The reason is that all the machines used for resharpening blades do their work either by honing on a flat leather car- borundum surface, or by flopping it be- tween two sharpening rollers. The re- sult of this treatment is to wear the blade down, and as the ordinary blade is made to project past the guard only a very be, \ C¢eeOeeretcetieteeterere aide LL See eee POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ff eaten et | short distance, after a few sharpenings the blade is so worn away as to become useless. Moreover, the edge is round and blunt when treated in this way. With the new device shown in the il- lustration, the blades are clamped in a holder and inserted in the machine be- tween revolving cylinders. The holder moves backwards and forwards while the cylinders are revolving, and the blades are edged by even pressure ap- plied to both sides. This puts a concave edge on the blades, as seen in the diagram, without wearing the blades down. They ‘can thus be re-edged over one hundred times, and will still be of the same width and _ will shave as well as when new. A_ one-quarter horse power motor drives the machine at a speed sufficient to edge seven blades in sixty seconds. 4 Quick Trestle Building in the West A three hundred and fifty-foot tunnel on the Southern Pacific Rail- way was closed to traffic last May owing to a cave-in when a fire destroyed some of the timbering. Since the tun- nel could not be re- opened for some time, it was decided to build a temporary line around the shoulder of the mountain. A trestle, four hundred and sixty feet long and sixty feet high at the highest point, ane” ee inders. hollow edge The blades are clamped in a_ holder and inserted in the ma- chine between revolving cyl- They are edged by even pressure applied on both sides by perfectly regulated mechanism was completed in nine days and nine _ hours - from the time the ma- terial was ordered by telegraph from Oak- land, three hundred and fifty miles away. The entire temporary line was completed in nineteen and _ one-half days. A safety razor sharpener which gives a to old blades.

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A Bungalow Mail Box The question of a suitable mail receiver is one which comes to every home own- er and which is not the easiest one in the world for the owner of the country or suburban place to answer. In the | accompanying il- | lustration is shown a _ com- bined receiver and pedestal which is at the same time serviceable and at- tractive. This pedestal is made entirely of red brick, with the exception of the mortar, which is of a light-gray color. The little “bungalow” mail box is made of sheet copper. The pier is about three and a half feet in height and two feet in width at the base. This feature is in en- tire harmony with the home before which it stands, which is composed of brick and which has hammered-copper hard- ware. A mail box on a special built pier Pasteurizing Milk for Babies at Home A new pasteurizer, which is built on the principle of a double boiler, is a sure and safe method for destroying harmful bacteria in milk. It is much like an ordi- nary large coffee pot A milk asteurizer ©X OCDE that thé flat built like a double tOP has holes large ae enough for bottles, and the inner recep- tacle is made up of tubes large enough in diameter to contain the bottles. The outer kettle is filled with water by means of a funnel placed in one of the openings in the top. After the water is boiling, the milk is completely sterilized in a few minutes. No thermometer is needed, as the double-boiler principle makes the heat control automatic, POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 197 Repairing Measuring Glasses On account of the thin, slender base of the usual form of graduates used for photo- graphic, cook ing and medicinal pur- poses, the gradu- ates are very eas- ily broken. The lid from a tin baking- powder can, filled with a fairly thick mixture of the i eee white of an egg i and p laster of A guaduate repaired Paris will mend with a plaster of Paris the rugged edges of ae the broken base when firmly pressed into the plaster mixture. After being left in a warm place over night the base will be practically as solid as stone, and will stay in the same condition for several years. The same cement used for this purpose also makes an excellent cement for other. articles of glass where a neat mass of plaster will not spoil them for use. Lighthouse Street Lights The street lights of one of the pretty residence districts of Berke- ley, Cal. are of rough granite, and stand about twelve feet high. They are round pillars, and are capped with a block of cement, upon which rests a large lantern of bronze and_ glass. A seat of cement runs around the post near the ground, for a rest- raat ing place, These “ mp, post built ke lamp posts were designed to suggest the appearance of a lighthouse. The effect is pleasingly nautical, Mee . aM a? HT ale E = See OTS SARE EO TT a

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798 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Ironing Board Troubles Are Over A device for holding covers on iron- ing boards has recently been invented. It consists of a set of six clips, which are screwed a certain distance apart in the center of the ironing board. These clips have two claws at both ends to hold the cover securely to the board. The claws are shallow and do not harm the fabric. The clips hold the ironing board cover securely When it is desired to remove the cover, the claws may be lifted and the cloth carefully drawn out from between the teeth of the clips and the board. When ‘the six clips are used the cover must lap over the board four or five inches on each side, but for the twelve-clip set the cloth needs to lap by an inch or two. By using the clips, covers for the ironing board are not torn as they are when tacked on. Aluminum the Most Abundant Metal Aluminum is the most abundant of all the metals. In its various forms it con- stitutes about fifteen per cent. of the earth’s crust, according to the United States Geological Survey. A few years ago it was a curiosity, and its value was fourteen or fifteen dollars a pound. At present it is selling at about twenty cents a pound. Already aluminum has displaced steel in certain classes of construction where strength is required in combination with extreme lightness, such as in the manu- facture of flying machines. An alloy known as duraluminum, containing about ninety-five per cent. of aluminum, is claimed to be as good as Bessemer steel for some purposes, although it is only one-third as heavy. This alloy possesses great hardness when annealed, and its melting point is above one thousand, two hundred degrees Fahrenheit. A Mail Box of Plate Glass A new mail box for the home has re. cently been invented which is made of glass, and the contents are therefore aj- ways in view. It is made of plate glass with a nickel top, and kiln-dried wood. The boxes are made to match the wood of any door or casing, and therefore are more ornamental than the old painted tin ones. The mail is put in the slit just under the nickel top, and taken out at the bottom. By pushing the upper part of the glass front it is made to swing in, and one may then reach in at the bottom for the mail. This operation is provided for by means of nickel-plated brass patent pivots, about a third of the way from the ~ top. For those who do not desire a plain glass, a ground glass is also made, which makes the contents sufficiently visible, but does not allow the addresses on the letters to be read. Mail may be easily removed from this trans- parent letter box Natural Gas in the United States. The production of natural gas in the United States for the year of 1914 amounted to more than five hundred bil- lion cubic feet. This record breaks all previous ones by ten billion cubic feet. ort

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Torpedo POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 1799 Cross and bell-like lights typical of mis- sion California. Above, arrowhead lights at Riverside What Electricity Has Done for Cali- fornia Street Lights By Albert Marple Novelty reigns supreme among the street lighting fixtures of the various municipalities of Southern California. It would seem that during the past few months the cities of that section have been trying to outdo one another in the presentation of the unusual, which is at the same time something practical. Names of streets are sometimes lettered on the white glass shades of these attractive street lights Streets illuminated by oil or gas lamps in large glass cases were, in the good old days, of about as many different designs as there were cities. With the use of electricity soon came the “arc” light, hung above the center of the street, still in general use. Now, however, the popular device is the more beautiful electrolier, the wires connect- ing which are run underground. These electroliers contain from one to a dozen lights and are of thousands of shapes and designs. They are made of both iron and cement, the latter form of ma- terial having grown rapidly in popular- ity in California during the past few years. Many of the cities of Southern Cali- fornia have titles other than their origi- nal names. For instance, Alhambra is called the “Crescent City,” Los Angeles the “Angel City,” Pasadena called “The Crown City,” Riverside “The Arrow City,” and so on. In many of these cities the electroliers have been designed so as to carry out the city’s nickname. This is shown in the arrowhead feature at Riverside. The cross and bell-like white glass shades are typical of old Spanish missions, some of which are still in existence in that section. With the exception of the lights the entire elec- ge ape RS IS rs amar os a en A Se YR a SR es ent ae a

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800 trolier is of cement. This nickname idea is also carried out in the cement and steel electrolier at Alhambra, the “Cres- cent City,” where a crescent has been in- corporated in the steel part of the elec- troliers. A new idea, that of numbering the electrolier to correspond to the street number of the house before which it stands, is also used. By this device even one driving along in the center of the street may readily find the house for which he is searching. Plain but attrac- tive cement lighting posts are also used in California towns, as at San Fernando and Redlands. Fender for Use on Pleasure Cars Many citizens have recognized the need for fenders for motor trucks by passing ordinances requiring them to be fitted; few, however, have deemed them necessary on pleasure cars. There is a pleasure car fender on the market, how- ever. It has been installed on their cars by many, Philadelphians, in spite of the fact that the device weighs sixty- seven pounds and costs fifty dollars. The fender is simply a rectangular frame with strong wire strung across it. Normally, it is held up from the ground so that its lower edge is about level with the hubs of the automobile’s two front wheels. When there is danger of run- ning into a pedestrian, however, a push on a button drops the fender to within an inch or two of the ground. The button is located on the POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE It will be noticed that the fender js not automatic. This is because the manufacturer thinks that “the unforty. nate who attempts to assist in his salyg- tion by obligingly knocking down a fen- der, does not live to tell the tale.” Ags a result the fender has been placed entirely within the control of the driver, Because the fender will be used but sel- dom, it has not been made capable of be- ing raised from the driver’s seat. It hag to be lifted back to place by hand, with a pull forward as well as a lift. 5 The pull forward is necessary to loosen a latch that holds the fender locked when lowered. This is to prevent a body from rolling under the fender, clogging it up, and allowing the front wheels to strike it. The Government’s ‘‘Canning Clubs” In the “Mother-daughter” canning clubs organized by the United States De- partment of Agriculture, nine hundred and thirty-eight public demonstrations were held during the year, with a total attendance of one hundred and eighteen thousand, three hundred and sixty-seven. These demonstrations were held pri- marily for the club members, but parents were always invited, and, as a matter of fact, more than half of those present were grown men and women. One of the great advantages of this club work, in- deed, is the fact that it serves to stimu- late the parents as well as to the children who make most of the membership. floorboard of the car, immediately back of the brake pedal, so that as the latter is pushed with the ball of the foot, the button may be _ pushed with the heel. This makes the dropping of the fender and the ap- plication of the brake simultaneous in time of need, while normally the two are entirely A push on a button located on the floorboard of the car drops the. fender to within an inch or two of the ground independent.

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‘mixer without elevating {the plant on its wheels A Portable Asphalt Plant A new portable asphalt mixing plant has been designed especially to meet the requirements of contractors and munici- palities having new construction and maintenance work to perform in scat- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 801 plant being within easy reach. The sand- measuring box and asphalt bucket are supported on scales. A drying drum of special construction has been designed for this plant to obviate the difficulties so often encountered in heating a sufficient amount of sand and stone. A Waterproof Sensitive Telephone Transmitter A waterproof tele- phone transmitter which is sensitive enough to catch the ticking..of a watch against the ‘walls of a fish globe, filled with water, has recently been installed in railroad dis- patching offices, in mines, on board stezm- ers, and wherever the most trying conditions This portable municipal asphalt plant brings pavement repair- ing within the means of small towns tered territory or in an amount insuffi- cient to make a stationary plant economi- cal. Its availability for bituminous road construction is an important advantage, since it can be hauled from place to place by means of a traction engine or steam roller. For a plant of its size prevail. With this trans- mitter, a conversation between New York and Chicago, and the striking of hours and quarters, were heard. Two sets of fif- teen dry cells, each connected in series, the sets in multiple, were used; and al- though the transmitter was submerged in the globe for hours, sound could readily be received and sent through it. and cost it is unusual in having a minimum eapacity of eight hun- dred square yards of two-inch sheet asphalt per day of ten hours. he capacity for asphalt- ic concrete, topeka mix- ture or asphalt macadam is much larger. The mixing platform of the plant is so elevated that a *"agon can be driven under it to re- ceive the load from the er excavating for this purpose. The platform is arranged for one-man operation, the levers for controlling clutches and A waterproof transmitter which is sensitive enough to record the tick of a watch through glass

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802 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Raising Cucumbers Three Feet Long One of the most remarkable cucumber stories on record comes from C. F. Hager, a farmer of Glendale, California. He states that during a single season in his hot houses in Glendale he grew cu- cumbers which reached the unheard of length of thirty-six inches and which weighed over five pounds. These, how Raising cucumbers at fifty cents a foot. Sometimes they are three feet long ever, were freak vegetables, the average cucumber being about a ‘foot in length and weighing about a pound. This size was known as “select” and averaged dur- ing the “off” season about five dollars per dozen, while the price soared, at different stages, up to six dollars. The “firsts” ranged from ten to twelve inches in length, being from ten ounces to a pound in weight and bringing an average price of about four dollars per dozen, while the “seconds” averaged about eight inches in length and brought about two and a half dollars per dozen. From his three glass-covered houses, twenty-five by two hundred feet, Mr. Hager has gathered more than twenty thousand dollars worth of cucumbers in two crops. A Chandelier of Crutches In a “faith-healing” mission in Calj- fornia an odd chandelier was constructed as a permanent testimonial of the belief which the founders preach. The chandeliers are each composed of five crutches. These are braced by walk- ing canes and the whole is held together by stout wires from which depend a nu- merous array of tobacco pipes. The canes and crutches are said to have been discarded by cripples who adopted the faith healing, and the pipes were cheerfully given by those who had renounced tobacco. Four canes hang from the framework and over these the electric light wires are wound, terminating in bulbs at the end of each. Where the main crutches in the con- struction of the chandelier meet in a rough point, it is finished off with two larger lights under a reflector. Crutches, pipes and canes made these chandeliers

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A ‘‘First-Aid’’ Pullman Car A Red Cross hospital Pullman car is traveling over the country, stopping in freight yards near factories, and teaching: railroad workmen and factory employees “first aid”.to the injured. It has already traveled more than forty-five thousand miles. So well do employers think of this free hospital training car that they allow workmen to attend the lectures and demonstrations on factory time with- out deducting from wages. The Red Cross car is equipped like a modern hospital and is manned by Dr. M. J. Shields, of the National Red Cross POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 803 Dr. Shields explains to the workmen who gather in the car how a stretcher can be made any time at any place with two coats and two fence posts. The coats are stretched over the fence poles, which are thrust up the sleeves. He also ex- plains how to make a tourniquet, with which to stop hemorrhage from a severed artery, out of a railroad flag or an old handkerchief, with a lump of coal, a stone or an old bolt. He shows how to revive a victim of electric shock. He is placed on his stom- ach on the floor with head turned side- ways. One man must then press with all Showing workmen | how to make a tour- | niquet from a ker- chief and a stick Society, who has personal charge of teaching workmen to administer “first aid” help to persons suf- fering from wounds, cuts, electric shocks, asphyxiation and sunstroke. toe a aN aN (In circle) A victim of electric shock is revived by methods which are not gentle his weight upon the short ribs of the stricken man in an ef- fort to pump the air -into the lungs. Then, to start the action with a shock, a second man must hit the bottom of the victim’s feet sharply with a stick.

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804 Delivering Locomotives on Motor Trucks With a saving in hauling expenses of one-third, the fleet of motor trucks in use by the Baldwin Locomotive Works of Philadelphia demonstrates the efficien- cy of such machines in unusual trans- portation service. The trucks are required to carry bodily small loco- motives to the railroad shipping points or to the docks for export—a method which was found less expensive to install than a special system of trucks to run the loco- motives on. When the trucks were first put into service by this great fac- tory, four of them dis- placed a dozen wagons and twice as many POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ratchet back and forth the ends of the chain are pulled together. The ratchet locks itself in position and holds the chain ready for closing the clamps. The operation of the tool is very simple. It is placed between the casin and the chain, and one of the hooks js horses, and the saving was so marked that the fleet of motors has been increased to twelve. Tool Simplifies Putting on Tire Chains A tool has recently been brought out which greatly simplifies the putting on of tire chains. The device consists of a dog and ratchet, the dog holding the ratchet in any desired position. The ratchet is fitted with hooks which grip the chain ends, and by operating the handle of the A device which makes it easy to apply non- skid chains Small shop locomotives are easily carried on a motor truck fastened to the last link on the cross chain, while the other is fastened to a link in the main chain. The handle is then operated back and forth, which slides the pawls on the ratchet. To re- lease the tool, the handle is pulled up- ward and the hook fastened on the cross chain will slip off. The device is excel- lent in that it allows the chains to be put on tightly, so that they do not become broken or lost. It may also be used asa rim tool in much the manner used with the chains. Interesting Railway Engi- neers by Means of Motion Pictures The Pennsylvania Rail- road is instructing its signal fitters and testing its locomo- tive engineers as to their knowledge of the signals by means of a motion picture ma- chine which has been installed in an inspection car. The car, which is forty- four feet long, is provided with forty chairs. The screen and machine are por- table, so that they may be quickly re- moved for use in a hall or room Four prominent aeroplane manufac- turers are shipping to Europe an average of fifteen aeroplanes a day.

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Suns and Worlds in the Making By Frederic Campbell, Sc.D. Late President, Department of Astronomy, Brooklyn Institute of Arts and Sciences HE theory of Laplace is still gener- ally accepted, that our solar system originally evolved from gas. Could we witness the process whereby this trans- formation was accomplished, how awe- inspiring it would be found! But our eyes are ever too close to the pages of the book; we are too near-sighted as well as too short-lived. Place us in some distant spot of the universe, where the light record of the creation of suns and plan- ets has just arrived, and we could peruse it all, as we can a much belated letter. But, with reference to thousands of similar systems, that is just where we are. The story is just now coming in. We look today on-the things of a century, a millen- nium, ago. Light traveling at the rate of one hundred great masses of glowing gas being trans- formed into solar systems like our own, then we have ocular evidence which even Laplace did not possess, that the solar system likewise emerged from a cloud of gas. While thousands of nebylae have been discovered in the heavens, only two are visible to the naked eye, namely, the great nebula in Orion, and the great ne- bula in Andromeda. The former, esti- mated at two thousand times the diameter of the solar system, seems to be a great though beautiful mass of confusion. The latter, estimated at six hundred times the diameter of the solar system, appears elliptical as to figure, and confronts us with problems comparable with those of Saturn’s rings and eighty-six thousand, three hundred miles a second, requires more than four years to come from the near- est star, per- haps thousands and tens of thousands of years from the farthest. Hence in every case we see not what is, but what was. Now, as we thus gaze into the depths of space, if we discover traces of any pro- cesses going on, we become actual wit- when first dis- covered. The condi- tion of nebulae is not revealed until photog- raphy co-oper- ates with the telescope, and, by means of exposures cov- ering hours, obtains record of details of structure that would _ other- wise never be known. The spiral pattern of some few nebulae has long been con- firmatory o f Laplace’s nebular theory. But there has recently come nesses of the processes. And if anywhere through space we behold Photograph by Yerkes Observatory. like a pinwheel. There are many such spiral nebule in the heavens. This is the one known as Canes Venatici. 805 in much evi- — dence of the In a sense it is, for it is revolving at spiral Bags 8 a dizzy speed—a speed a thousand times that of the ter of other earth. Here we see a world in the making nebulae.

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THE BIRTH OF A SOLAR SYSTEM Photograph by Yerkes Observatory. The great nebula of Andromeda is often taken for a star of the first magnitude, yet the telescope discloses it as a cloud of luminous gas, whirling on its axis in a plane at an angle to our sight, a mass of star matter in the process of becoming a whole solar system. When the process is completed, aeons hence, the system will be far vaster than our own. Although its speed is terrific, yet in the history of astronomy not the slightest change has been noted 806

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es bn Prentetemenmen nN nasiores we ea Nh spcscemoraeengs The conclusion seems torced upon us that practically all are in a state of rota- tion, and are hence supplying the centri- fugal force to throw off the rings which, Laplace taught, roll themselves up into planets revolving about central suns. The very confusion of the mass in the great nebula in Orion suggests that some kind of motion has here been at work. Portions of the nebula may be lacking in illumination which might otherwise show it to be spiral, rotating in space. The fact that the spectroscope has recently demonstrated motion in this famous nebula confirms the suspicion that it is doing POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE _ 807 But, when opportunity is given to look directly down upon a nebula, there re- sults startling evidence of its being in ro- tation. There is no other way of explain- ing its remarkable details of structure. Some look like the propeller blades of a motor boat; some appear like spinning wheels ; and some are actually caught in the act of throwing off rings, which are seen condensing at certain centers, roll- ing themselves into planets, henceforth to travel around their suns. The great ne- bula in Andromeda gives striking evi- dence that it is working out another and a greater solar system than our own. In short, it what we know that so many others are. The spiral nebulae, of which so many are now found, may be divided into two classes, those that are seen edgewise and those that are seen flat. Those seen edgewise sometimes pre- sent little more than a central sun, not yet seems that, in studying the nebulae, we are being ad- mitted to the very workshop of the uni- verse, and are permitted to watch the ac- tual process of turning out worlds. Noth- ing in the heavensis. better fitted to fill the very soul with awe. As in the case of the “fixed Photograph by Yerkes Observatory. fully con- densed, cleft laterally into halves, show- ing that some- thing stands between their central portions and our- selves. This something is evidently a thin disc of matter surrounding a central sun, but whose extension far into space we are unable to see. In other cases, however, the thin disc is plainly visible, and it becomes more apparent, if the nebulae be viewed somewhat tipped, as it is considerably in the great nebula in An- dromeda, the reason for its elliptical ap- pearance being obvious. That these gases take the flattened disc form instead of the globular is convinc- ing evidence that they are rotating, the centrifugal force thus generated flinging their elements far outward. The Great Nebula in Orion is a mass of glowing gas which forms the middle star of the “sword” of Orion. Through its luminous body gleam stars far beyond it. Its confused mass is now generally believed to indi- cate that it, too, is in rapid motion stars,’’ our lives are too brief,too feeble our eyes, to detect the actual mo- tion. But science determines the unmis- takable facts, and reasoning does the rest A Natural Substitute for Eggs A Southern cook has patented a sub- stitute for pudding and cake eggs. Yams are boiled until they are completely cooked, after which they are peeled and cut into thin slices, baked in a slow oven until they are crisp, and then powdered. Two drops of rose extract are added to each teaspoonful of the powder. One tablespoonful of this composition is claimed to be equal to one egg in the making of pastry, cakes, muffins, etc.

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808 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Reading Gas Meters with the Camera A special kodak has been perfected for the use of men on meter-reading routes, the object being to enable them to bring into the office at the close of the day’s work photographic evidence of the position of the dial pointers on the me- ters of the customers visited. In order to take the reading of the gas or electric meter the man sent around by the company simply holds the camera opening against the meter dial glass and presses a lever, which automatically opens the shutter for a definite period and at the same time lights four small battery - operated lamps to illuminate the meter dial. Af- ter each exposureis made, the shutter is locked and can- not be operated again until the film roll has beenturned to the position for the next picture. The device can also be used as a hand lantern in dark passage ways by pressing the lever a part of the way down with- out operating the | shutter. Each roll of the wi special film used Ime ,S the meter and provides for thus obviates dis- seventy-five expo- putes sures. Two addi- tional rolls can be carried inside the camera box. Exhibition Visitors Design Homes The Institute of Architects of Sydney, Australia, has arranged a novel competi- tion in connection with the “Ideal Home Exhibition,” which is shortly to be held in Sydney, and of which twenty-five per cent of the receipts will be given to the Red Cross Society. One of the objects of the exhibition is to stimulate interest in the making of an ideal home. In the competition every visitor will be asked to compete in the building. decorating, furnishing and equipping of an ideal home from material exhibited. Raising $5,000 Silver Foxes for Market To raise silver foxes calls for a pair of foxes, which will cost from $150 to $250 each for the common foxes, and up to several thousand dollars each for the best. The prices of furs and of breeding silver boxes have fallen considerably since July, 1914. The prices, running into thou- sands of dollars for live silver foxes, were based, not upon the fur value of the animals, but on their possibilities as breeding animals, in an industry in which there was great speculative excitement. The business of fox breeding will be on a much more stable basis than at pres- ent when the value of breeding ani- mals bears an ap- proximate relation to the value of their pelts in the open market. The profits in silver fox farming prior to 1910 were realized mainly from the sale of pelts; since then they have been derived al- most entirely from F-Winding Key Z G-Exposure Lever H-Flesher Button (Searchlight) A-Unexposed film B-Exposed Film\, C-Lens 0D-Electric Lights |] ££-Batteries e ee ae et wy i ccemteieeaail The device is so constructed as to furnish light for its own photographing. It is capa- ble of many uses besides meter reading the sale of live foxes for breeding pur- poses. There has been a sharp decline in the prices of breeding stock.

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A Time-Saving Envelope To business men and others who have to open a great number of letters and who find the old-fashioned flap en- velope a time-consum- ing nuisance, the idea contained in a recent invention would be an effective time-saver. To enable the recipient of the letter to open it with a single stroke, a set of parallel slits with over-lapping ends is provided in the flaps of the en- velope. A small tongue is cut in the paper at the point where the lines meet. When this tongue is pulled, the paper The perforated flap Perforations along the flap make this envel- ope easy to open tears diagonally from one slit to another in rapid succession. Thus, with a swift movement, the envelope is neatly and squarely cut open without injuring the contents. A Hydrogen-Oxygen Motor That Will Not Work According to the newspapers, George Harris Moriarty is the lucky inventor of a new motor for automobiles, in which he explodes hydrogen-oxygen, after compressing the mixture, obtaining 89% of the theoretical power released. To put it mildly, somebody made a mis- take. Hydrogen-oxygen, when ignited, contracts, a quart of the gas mixture con- densing into a few drops of water; there is no expansion of any kind and the only power which it would be possible to ob- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 809 tain would be the pressure of the at- mosphere upon the outside of the cylin- der pistons, endeavoring to push the pis- tons into the vacuum caused by the con- densation of the gas mixture. The great- est power obtained would be by making the mixture as thin as possible, not to compress it, and even then it would only amount to 14.5 Ibs. per square inch, the pressure of the atmosphere. Device for Dimming Auto Headlights Headlight dimming is now compulsory in so many states that any motorist who tours must have some device which will secure the desired dimming effect. Sev- eral of these devices have already been described in this magazine. Nearly all utilize in some way or other the idea of catching rays projected horizontally for- ward and upward and turning them slightly downward to the road surface. The new reflector shown in the ac- companying illustration consists of a series of prisms placed in such a man- ner as to throw a strong non-glaring light five hundred feet ahead. Prisms, arranged clapboard fashion, run across the front lens. The lower end of each prism overlaps the next lower one. The prisms are arranged at such an angle as to cause the proper deflection of the direct rays. A headlight dimmer consisting of a series of prisms arranged clapboard fashion

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810 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Making Motion Picture Cartoons with Ammonia Fountain Pens By Horace A. Fuld About a year ago Charles A. Birch- Field, the illustrator, was asked by one of the film companies to draw some car- toons to be reproduced in their films. He agreed, and proceeded to take what he imagined to be short-cut to easy money. The task was the drawing of several cartoons (not the animated ones) that you see now in almost every pic- torial news-weekly. The subjects were to be the latest styles, treated satirically, as well as events that come under the head of caustic pen comment. At the time that Mr. Birch-Field was asked to do this work, the method of procedure was about as follows: A drawing board was arranged under a battery of high-powered illuminating lamps, with the camera rigged up direct- ly overhead, the lens pointing downward and focussed on the drawing board. About sixteen pictures per second were thus made, more than ten images per second appearing as a continuous image to the eye. As the average cartoons for the weekly news picture may occupy one hundred feet of film, and as, further, a the work less arduous. Asa result he has devised a very promising process, Mr. Birch-Field first has an enlarged photograph made of the cartoon or draw- ing to be reproduced, the size of the en- largement being fourteen by eighteen inches. This enlargement is dipped in a bath of bichloride of mercury, washed in water, placed in a solution of hydroflu- oric acid, rinsed again, and lastly, treated in a bath of bichromate of potassium, dipped in water, dried, and placed flat upon the drawing board. As in the old method, the camera faces the drawing board, lens down, the drawing having completely disappeared from the en- largement. Lamps are ranged on either side of the board for the required il- lumination, and all is ready for the ac- tual photographing of the cartoon. With a fountain pen filled with am- monia the original lines of the enlarge- ment are retraced in the manner illus- trated, exactly as they appeared prior to their chemical erasure. They reap- pear as by magic. The original drawing (or a duplicate enlargement) is used to guide the hand along the original lines. A slip does not matter; no mark results where there is no line beneath. The cartoon is photographed by a con- tinuous revolu- than a foot per second travels through the fraction more tion of the camera crank and a gradual projecting ma- and seemingly chine that throws the image on the screen, one thousand seven hundred differ- ent photo- graphs must be taken. This is done automat- ically, in most studios, simply by pressing a button each time a picture natural line drawing, at whatsoever point the pen is applied, results. It takes just four minutes after the pre- pared enlarge- ment is on the drawing board, supposing that we are dealing with a subject one hundréd is taken. Mr. Birch- finding some would make es three small cuts show the steps in producing the : nished effect of a rapidly drawn animated cartoon. Field set about At the left is the original drawing; the middle cut is the drawing washed out by chemical baths; at the right wayt hat the ammonia-filled fountain pen is bringing the car- feet in length, ‘to make a film negative read for the devel- oper and print- toon back to life er. Y NYY \ ds

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Chain-Shot in a New Form A shell containing two weights and a chain, instead of the usual shrapnel balls, has been devised by a Connecticut inventor. The object of this new form of explosive projectile is to tear down wire entanglements and other obstruc- tions in its path. This chain projectile is provided with a bursting charge of When the shell explodes two weights con- nected by a chain are thrown out and tear down the barbed wire entanglement powder and a time fuse, as in ordinary shrapnel. The chain is free of the shell, so that when the latter explodes in front of an obstruction there is nothing to im- pede the chain and its weights. It is evi- dent that the inventor was inspired by the chain-shot used in the days of frigates to carry away rigging. A Lifeboat Which Cannot Capsize The accompanying illustration shows a life-boat which, on account of its pecu- liar construction, may be considered practically unsinkable. Its body is made of an external shell with tapering ends through which extend two L-shaped This lifeboat always remains right side up POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 811 tubes for supplying the occupants with air. But this is not the only function of these tubes. They revolve freely on their watertight bearings in the tapering ends; and from the inner extremities of the tubes there is suspended a wooden floor with seats mounted on its upper surface. Tanks containing water and food are se- cured to the bottom of the floor. Thus the floor is actually independent of the shell, and no matter how severely the life-boat may pitch in a heavy sea, the claim is made that the floor within will always rotate with the L-shaped tubes and maintain its level. Strap Pad Oiler for Auto Springs Few automobiles of the cheaper type have a provision for oiling the springs. Oiling the spring leaves seems to be the thing a motorist usually forgets, and many a touring party has been compelled to turn in at the first garage to have the spring leaves pried apart and graphite or other lubricants forced between them. As a sort of insurance against lack of lubricants an extremely simple and cheap device has been invented. The leather An oil pad strapped on springs after this fashion provides oil in one of the parts most commonly overlooked strap passes around the leaf spring, and is held in place by an ordinary buckle. The strap is lined with a pad of wicking, which is saturated with oil to feed the lubricant in small quantities to the spring leaves, then the swaying of the car forces them apart. A hole in the strap, pro- tected by a cover, admits the spout of an oilcan. The leather is chemically treated so as to prevent absorption of oil. Two straps are required for each semi-elliptic and four for a full elliptic spring.

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By William CCORDING to the records in the division of ornamentation of the United States Patent Office, there are a round dozen “improvements” in Christmas trees. They are classed un- der “artificial trees.” “Improvements,” according to the examiners who have charge of these patents, is used advised- ly. For your modern artificial tree is fire proof, collapsible for transportation, admissible of gas or electric lighting, and “as good as, and as sightly as the natural tree.” One of these inventors has even applied a more practical possibility still. “My tree,” he writes in his patent speci- fication, “can be dismantled of Christmas decoration, pegs inserted where the arti- ficial branches were and be used as hat or clothes rack during the rest of the year, then re-decorated when Christmas returns.” The industry of artificial Christmas tree development, though of comparative recent date, is a direct outgrowth of an enormous industry in artificial fruits and flowers. F. C. Bowen, the pioneer inventor of artificial trees, designed his to be adorned for feast and gala days, for advertising display or for such other use as con- sumers cared to put it to. Though he makes no mention of Christmas trees in his application for a patent, his specifica- tions form the nucleus for later ideas ‘‘Improving’’ Nature’s Christmas Trees K. Marshall which improve his improvement on nature. Mr. Bowen’s artificial tree becomes an . imitation of the natural tree by providing a stem supported by a base. His stem and branches may be covered with any material which imparts a likeness to nat- ural bark. His branches are attached to slight projections from the “trunk” by coils of wire. When August Wengenroth, of Troy, New York, submitted specifictions for an artificial tree his design was to offer an announced substitute for a Christmas tree. “My invention,” he wrote, “fur- nishes a portable imitation Christmas tree ready for use. It can be made fire proof if covered with alum or other substitute, and it admits being used from year to year if properly stored and packed.” Mr. Wengenroth’s innovation which, in the main, supplies the basis for later improvements, consists of an up- right trunk to which are applied a num- ber of detachable branches of wire cov- ered with chenille—a soft tufted or fluffy cord of silk, wool or worsted. The ends of the branches have spirally bent ter- minals which hold drip cups in which candles can be fixed. Ground cork or similar material can be used to apply to the trunk and branches to give the tree the color of the natural tree. To improve the artificial tree further 4 5 6 7 1, The Wengenroth tree, whose detachable branches have drip cups for candles. 2, The bare frame of Miss Crook's tree, which is made of twisted wire. 3 and 4, A tree invented by W. T. Strasser, with flat leaves which slip into the tube for storage between seasons. 5, The Hummel tree, which approximates nature better than any of the others. 6 and 7, Sectional views showing the means of applying the branches to the Hummel tree . HOW INVENTORS HAVE TRIED TO IMPROVE ON NATURE'‘S CHRISTMAS TREES 812

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE and make it a nearer resemblance to the natural fir tree, he suggested the idea of driving “eyes” into the trunk, which aimed toward a better imitation of the natural aspect of the bark. This imita- tion was so perfectly carried out that the inventor arrived at a realistic imitation of the growth of branches in their grad- ual diminishing from the lower to the upper trunk. The leaves appear in his specifications as elaborate imitations in muslin, paper or “other flexible mate- rial.” They are attached to the stem of the tree by dipping them in mucilage or other adhesive, and while the leaves are still wet, they are sprinkled with scales of mica or similar mineral. This gives the representation of snow, which the inventor thinks is “a beautiful effect.” Annas Hummel spent more effort in arriving at an imitation of the Christmas tree than did any of his predecessors or followers. His idea for a trunk is a very stout stem built in sections so that it is readily collapsible for ship- ping or storing. The branches are at- tached to the main stem by wedging de- vices. In other features he holds to the imitation of the natural tree by corking the trunk and imparting the natural tapering effect to trunk and branches. It was Mr. Hummel who claimed for his invention the extension of its prac- tical possibilities in easily converting it into a hat or clothes rack when its Christ~ mas mission was done. Three women are included in the list of inventors of Christmas trees. They are Mary C. Crook, of Nebraska; Eva C. Leonard, of Pennsylvania, and Mary D. Berry, of Connecticut. Miss Crook claims that her conception of a Christ- mas tree is to provide one that is “strong, inexpensive, fireproof, attrac- tive and adaptable for collapsibility and easy transportation.” Its sub-structure is of wires which are twisted to hold branches and trunk together. This is covered by a superstructure of material simulating the naturalness of the tree. Miss Berry advances on the concep- tions of her predecessors and claims that in her tree “it is almost impossible to tell it from a real tree when it is dressed.” It combines all the improved features and employs needle-like attachments to the branches which admit of secure and easy 813 decoration with candles and ornaments. An original idea for a Christmas tree was given out by Miss Leonard. Her tree has a stiff, symmetrical framework. Its upper structure is composed of super- posed tiers or rows of branches gradu- ally diminishing as they ascend. Metallic bars which enclose this creation bear a cup for a candle at each of its corners. This is alike fireproof, portable, and available when the forest fir is not. Unspillable Medicine Bottle and Eye Glass A new automatic bottle, which allows even a small child to take his medicine without aid, has recently been placed on the market. There is no possibility of spilling the liquid and no spoon is neces- perfectly sary. Hence it can be conveniently car- ried in the pocket. A wide-mouthed glass bottle with a screw cap filled with a rub- ber plug is the bottle proper. Through the rubber plug a glass tube passes, which ends in a funnel-shaped cup, on which different sized doses are indicated by lines and figures as in a graduated meas- ure. To take a dose of medicine, the cap is unscrewed and then screwed down, the latter operation compressing the air in- side and forcing the liquid to rise to any desired height in the tube. Another de- vice of like order is the eye-cup, which utilizes the same principle embodied in the medicine bottle

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The Fickleness of Watches Explained By Leonard Keene Hirshberg A.B., M.A., M.D. Tests with watches show that their environment affects their timekeeping qualities almost as much as human beings are affected by their surroundings. Suspension in various positions results in various rates of pendulum-like vibration, which have an invariable effect on the timekeeping, which can even be rated for distinct localities ATCHES and clocks are such com- ; monplace, every-day articles of necessity that many persons think there is nothing new to be learned about them and the time they keep. Think but a mo- ment, what time itself is. Time is not a thing that is kept by watches and clocks, much less correctly. A watch in the house measures, not keeps, altogether different time from the same thing out-of-doors. Moreover, a watch in the sunshine is an entirely different watch in the rain. In the summer-time heat expands the springs, balance wheels, steel, gold and other parts of the clock or watch, so that the effect is noticeable. Friction and size have much to do with this, also. In cold weather, the metal and other elements in a timepiece contract and shrink to such an appreciable extent that friction and interference of one wheel with an- other are reduced to a minimum and the watch becomes fast. How, then, is any- one to know precisely what time it is at any moment? What is a moment? The impossibility of ever knowing the absolutely correct time at any place as well as other important facts of time- pieces has just been made by the distin- guished English Professor Turner, of London. It was all brought about by a curious experience he had with his watch on the Isle of Wight. Owing to the breaking down of a wire- less apparatus and the difficulty of get- ting the official Greenwich time, which is regularly obtained by astronomical ob- servations of the sun, moon and stars, Professor Turner attempted to correct the Isle of Wight time by a watch, which he wore, with a scientifically determined summer slowness of seventh-tenths of a second a day—a fairly accurate time- piece, one must admit. This watch had been set at Greenwich, a much warmer place than the Isle of Wight, yet the pro- fessor was startled to find suddenly that his chronometer began to gain fifteen seconds a day. Hitherto, it had been his custom to keep the watch in a fixed upright posi- tion during the night, but on the Island he had suspended it from a bedpost by its chain. On the third morning, it was seen to be swinging like a pendulum, un- der the influence of its own balance- wheel. I have had this same experience with one of my watches, which is always sus- pended by a loose wire ring from a cross bar of my desk-lamp. One of my as- sistants has frequently called my atten- tion to the same fact, but neither of us thought it was due to its own balance- wheel, but rather to outside rumbling of carts and cars. When Professor Turner returned to 814 his observatory, the watch was checked eetett FR oe Ot os Pe Ot a —”~

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up by the astronomical clocks for one hour and found to be keeping perfect time. It was then suspended from a nail, so that it would vibrate. Its rate was found suddenly to increase and be- come two and three-tenths seconds fast per hour! When it was in his vest or watch pocket it was correct, when sus- pended it was two to three seconds fast per hour. Another watch, similarly tested, was correct in his pocket and from six to seven seconds fast every hour, so that in a day it went two or three minutes fast. Each watch was dif- ferent from the other. These new dis- coveries show how important it is to con- sider what you do with your watch when you change your clothes—especially dur- ing the night. Several experiments have been made to discover the conditions which cause this increase in a watch’s rate. Many and various kinds of watches were tested and every one without exception was found to be similarly affected. It was found that the oscillations were invar- iably intermittent. One watch—the one first mentioned—made eight beats and then stopped. Evidently the number eight was due to the relation of the period of the watch, acting as a pendulum, to the period of the balance-wheel. A light, metal clip, as in the pictures, was made to hold the watch, fitted with two adjustable pivots. Thus the extent of the swing—the “period’—could be readily varied. A mirror was also ar- ranged so that the beam of its reflected light could be used to measure the extent of the oscillations. The balance-wheel made one hundred and fifty oscillations a minute. Tests were conducted with the watch swinging at various frequen- cies from one hundred and twenty to one hundred and forty-seven. The rate in seconds per hour was found to be about five and four-tenths times the extent of the degree of oscillation. This five and four-tenths depends on the power of the mainspring and in the weight of the watch and varies in different watches. Watches gain consistently and the near- er the frequency of the watch’s swing approaches that of the balance-wheel, the greater is the gain. Moreover, with the watch oscillating in a vertical plane, the nearer the center is brought to the axis POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 815 of rotation, the more the watch becomes a flywheel itself, rotating on its own axis. With the watch hung flat and face up- wards as shown, there is not much effect on the time of the watch. At most other angles, the number of seconds of increase varies and the wheel also up to one hun- dred and eighty vibrations per minute. A locomotive engineer on a railroad innocently wrote to a scientific periodical that his watch had been carried thou- sands of miles. His letter was seen by Professor Turner. The engineer wrote that he had found that while the vibra- tion to which his watch is subject makes little difference, if used on similar en- gines at similar speeds, yet a different class of locomotives with varying velocity makes his watch fast. A watch that gained only two minutes a day on the ground, on a thirty-mile an hour locomotive with a five foot six inch driver kept correct time. On a locomo- tive with a seven foot three inch driver, making forty to seventy miles on hour, the watch would gain from sixty to ninety seconds a day. No wonder that locomo- tive engineers find that their watches are rarely correct at the end of a run. Perhaps the same can be said of clocks in automobiles, ships and aeroplanes. Motoring, riding and walking all cause errors in watches. A man who motors, takes a ferry, then a train, and finally walks will find that his Sunday-go-to- meeting time on the same watch is much slower than week days. Jewelers also have blithe excuses (animal magnetism and similar superstitions) to explain why the same watch on Jim Smith changes its time on Bill Green. The true ex- planation now appears for the first time. Playing Geometry With Corks An interesting geometrical experiment can be performed with a pan of water in which several corks pierced with needles are floating and under which a perma- nent bar magnet is placed. A single cork will float to a position directly over the magnet ; two corks will float to points on either side of the bar, three corks will form a triangle, four a rectangle, eight an octagon, etc.

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816 Removing Snow by Dissolving It The time and expense involved in snow removel in large cities are largely controlled by the distance to the dump- ing ground. This factor is so important that it is often a prohibitive one. To Dumping snow into sewers and dissolving it with water has saved New York hundreds of thousands of dollars a year overcome this difficulty, and to supply dumping grounds at convenient intervals in the city is the object of the invention shown in the sketch. By means of two slanting chutes extending from the street surface into the drain pipe the snow is dumped into the latter. Here a rapidly revolving jet of water, supplied from the hydrants of the city’s fire supply, causes the snow to melt and leads the water away through the city sewer sys- tem. More than one stream can be used to melt the snow at the bottom of the chutes; and likewise, as many of these melting stations can be established as may be required by the size of the city. A Motor Sleigh A German inventor has added to the long list of inven- tions designed to drive a sleigh auto- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE matically, the device illustrated in the sketch. Its motive power is supplied by a gasoline engine mounted behind the driver’s seat. By means of a chain the power is transmitted to a_ horizontal crank-shaft which operates the two plunger-rods. These are placed one above the other and are made to move through two guiding grooves. By means of the sharp points these plungers are made to engage the snow, ice or other road surface, and so to propel the sleigh onward. A brake is also provided with a point to be dug into the snow. New Front Spring for Small Cars At a time when many mechanically- inclined Americans construct their own automobiles from spare parts and dis- carded old cars, the type of front spring shown in the accompanying illustration should be of particular interest. Spring- ing the front axle of a light car has al- ways been a difficult matter, particularly if the spring is to be a transverse one, The spring eliminates the roll of small motor cars pivoted in the center, since in such a case the car shows a tendency to roll on un- even roads. To overcome this well- known tendency a British engineer has designed a type of front spring which combines the good points of the cantilev- er with the lightness and strength of the front transverse type. The two sections of the spring are joined by two spring clips, equally distant from the center and the ends of the springs. The end of the frame rests upon these clips, so that no front axle is required. As each spring, because of the position of the clips, acts as a cantilever sus- pension, the car rides easily, while the wheels - rise and fall in parallel lines. There is no appre- ciable roll, even on rough roads at high speed.

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The Home An Electrical Egg-Beater An electrical egg-beater, so simple to make that it can be readily understood from the sketch, is presented herewith. Secure a base, 614” long and hinge it onto an 18” upright board, as shown. Fasten a block, about 2” thick, at the top, and to this fasten a small electric Ayr th motor. A brass E | stem is fastened to the shaft, and hor at the end of it are soldered some i brass. strips, to make the “beat- er.” The base has a hinge so that it can be lowered at will to hold the "glass, containing the eggs. The motor, however, may be fixed to slide up and down which, of course, eliminates the necessity of hinging the base. Beating eggs cena Electric Lighter for Gas Stove An old automobile spark coil of the vibrator type and two or three dry cells are the principal parts needed for this device. If the coil has three leads con- nect up as shown and if it has four leads hook one end of secondary on to primary to save extra wiring. Use straight, heavy, portable cord to carry the current to the lighter. Around the outside of this cord is wrapped a single cable which connects the battery with contact spring. Details of the lighter are also given. Bend the tip of the gas jet slightly 817 Craftsman towards the center and drill four holes about 4g” from the end. In connecting secondary to center wire, solder and cover connection with rubber tubing or tape before placing point wire in rubber plug. Solder one battery wire to 4%” pipe, assemble parts and heavily tape handle, then bend the base of the contact spring around it, placing this so that the end of contact will touch the brass tip when pressed. To prevent shocks it is a good idea to tape the whole handle after com- pletion. If the point is exactly in middle of tip. the sparks will spread out in all directions when the circuit is closed. $ holes oes Tt ‘ Lead Lass cc i ear ; Spark Coil caaumarimmmmnindiip-ananaass. Center mre "4 brass An electric gas lighter made from left-over materials Indelible Ink for Marking Clothing Nitrate of silver 5 scruples; gum ara- bic 2 drachms; sap green 1 scruple; dis- tilled water 1 ounce. Mix together. Be- fore writing on the article to be marked apply some of the following: Carbonate of soda % oz. and distilled water 4 oz. Let this last, which is the mordant, get dry, then with a quill pen write what you require.

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818 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE An Effective China or Curio Closet A simple but very convenient china or curio closet to be nailed to the wall can be made for less than $5, using best grade chestnut for the woodwork. This in- cludes the leaded glass, or, if one prefers, small diamond panes of ordinary win- dow glass, with the lower half of the doors of plain glass. The back of the closet is made of fin- ished boards nailed to end cross-pieces, grooved and tongued ready to fit. The top board can be cut with a scroll saw or a key-hole saw after any simple pat- tern desired. It rests on the top of the closet, and is held in place by the side uprights. The side uprights are made of 2” x 2” sticks, cut square and polished. The ends can be finished plain or topped off with some simple metal ornament. The DETAILS OF Back J This closet can be made for less than five dollars, including leaded glass doors side, top and bottom boards of the closet are plain finished lumber; and the orna- ments of wood nailed on the outside when knocked together. With the lum- ber cut in the dimensions specified the assembling of parts is little more diff- cult than the nailing together of a box, Tongued and grooved, the corners are more finished, but they can be nailed and glued together with almost as good an effect. Small-headed wire nails should be used, driven 4” in the wood, and the heads puttied up. The doors are the most difficult and costly of the structure. They are not, however, beyond the skill of any one at all handy with tools. As the glass must be fitted on the inside, a groove for it must be gouged out with a chisel. If leaded glass is used for the upper part, it can be ordered of the right size, and then fitted in with cross bars at 6” inter- vals. If small diamond window panes are used it will pay to have the frame made at a mill. Such a sash, with the glass in, and painted one coat, costs about $1 a door. Brass hinges, and a small button or knob, complete the closet. Finished off in hard oil to a dull polish the closet is an ornament to any den or dining room. It is intended to be screwed to the wall, but it may be hung if the lower ends are fastened to a substantial base, such as the top of the wainscoating. Clearing Ready-Mixed Paint Amateurs doing jobs of painting around the house generally use prepared paint, which is often troublesome, un- less the dealer keeps fresh stock on his shelves. The solid matter cakes in the bottom of the can, and it is very difficult to stir it up. When this occurs, pour the paint into a larger pail, taking care to get all the solid matter, digging it with a knife if necessary. Then take a strong egg-beater of the dover type, and stir the paint vigorously. If the egg-beater is washed immediately in turpentine or kerosene, it will not be harmed for kitchen use. This will be found a great improvement over the tiresome and unsatisfactory method of stirring with a paddle.

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An Ice-Card Holder SIMPLE holder for ice-cards or milk-tickets is shown in the accom- anying diagram. he holder is made from a strip of brass bent as shown and fasten- ed to the window frame with several tacks. ‘The card is inserted between the strip and the frame, and may be secured with a brass clip. A Home-Made Gas-Jet Heater HE accom- panying sketch shows a f£ simple way of §£ quickly warming a feta room from an or- & dinary gas jet with an ordinary two- quart kitchen dish and three picture hooks. If the lat- ter are not avail- able a piece of iron wire can be bent into the characteristic “S” shape of the pic- ture hook and serve equally well. Bend the wider sweep of the hooks down so that each will grip the lower edge of the inverted dish more firmly and place the other end of each over the top edge of the shade. The hooks should be spaced about equally around the shade and should be movable until the dish is securely gripped in place, care being taken not to move the hooks into a position where they exert too much pull on the shade or are in danger of letting the dish tip over. With the ordinary shape of two-quart dish and gas shade, the picture hooks will be found just about the right length to afford a firm, satisfactory setting of the inverted dish as shown. The prompt heating effects of this simple arrangement are quite startling in a moderate sized room. This is chief- ly due to the downward deflection of the heat by the sides and top of the in- verted dish. The action is independent of the radiation afforded by the surface POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 819 of the heated dish, as well as of the heat received from the circulation of the air currents which go up to the ceil- ing and thence are reflected down again. If a clean, bright dish is used the re- flection of the heat rays downward will be considerably increased. The latter will also serve as a light reflector so that a comparably small flame will fur- nish heat and also sufficient light to read by, which the metal drums usually sold for this purpose will not do. To Remove Paint Spots From Windows AINT spots may be readily removed from window glass by means of an old safety razor blade fastened in a slit of a wooden handle by means of two screws. The handle should be about 8 inches long, 1 inch wide, % inch thick, and cut so as to fit the hand. This paint re- mover is used like the or- dinary paint-scraper. Wire Broom Holder VERY effective and simple device for holding a broom is made of heavy wire and fastened to the wall or some other convenient place, by two screw-eyes, the eyes forming bearings for the wire. To hang up the broom insert the han- dle into the large eye about four or five inches. The weight of the broom keeps it in position. Holding a Window in Place INDOWS _-¢ that are Yj; yy, : Ye Y not provided with - ll a Vp weights and pul- A ly vy LW H AYO r" PPT WHT] | leys can be held up with a hook. The hook should be placed in the = wood casement - adjoining the window and an t = eye screwed into the top of the window frame. The upper section of the win- UIA) Py dow can be held up by means of a nail driven below the frame.

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AeeemeS sees pipet: evi 820 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANOE How to Make a Match Holder One of those fancy match holders that pass out matches one at a time may be made by any boy who has a knack for handling tools. The accompanying draw- ings show how it is done. The whole thing may be made of mahogany or any other hard wood and its ornamentation is limited only by the skill and ingenuity of the craftsman. The match holder is circular in shape and the inside length is the size of the match, plus 4%” for clearance. The sides are made in two parts and are hol- - How to make a holder that will pass out one match at a time lowed out so that the thickness of each is about 4%”. The ends are 14” thick and are cut to a 2” circle. When the parts are made place the bar- rel temporarily and mark the size of the pedestal on the underside and the space through which the pedestal is to pass in carrying the match to the outside. These holes should be carefully cut out when the barrel is ready to be glued together. The inside size of the open box should be that which will fit the pedestal exactly. The cross bearers for the spiral springs to rest on are cut 134” long and the breadth of the outer ends are 4”. Glue the rectangular and the circle part of the barrel together and fit the cross pieces for the springs in position. In fitting together the various parts of the model take the two cross pieces for the springs out of the barrel. Slip into place on the barrel the pedestal which has been detached from the base. The cross pieces for the springs are then put in position from the under end of the pedestal. The springs are next put into the sockets and the pedestal screwed to the base. Fill the match space three-quarters ful] and to use, grip the ends of the barrel, press downward, and a match will come through the aperture in the barrel. The match holder can be made without the wire springs, but the barrel holder must be lifted up as high as it will go and then allowed to slip down again be- fore the match is obtained. Some Stain-Removing Recipes A good general stain remover, which is practically a bleaching agent, may be made from the following formula: Prepare a 20 per cent. solution of acetic acid. One part of strong vinegar mixed with four parts of water may be used for this solution, which should be labelled No. 1. A second solution should be made by dissolving 5 grams of bleach- ing powder in 100 cubic centimeters of boiling water. Continue the boiling until a pink color appears. Filter this solu- tion and add 50 cubic centimeters of cold water. Label this preparation No. 2. To remove stains apply No. 1 until the spot is thoroughly wet. Absorb the su- perfluous liquor with a blotter and apply No. 2. Rinse and repeat the application if necessary. Medicine stains on spoons may be re- moved by rinsing in weak sulphuric acid. Acid and grass stains may be removed by using solutions No. 1 and 2 as described above. For grease spots liberal applica- tions of gasoline, or equal parts of am- monia and alcohol will act as efficacious removers. Paints and varnishes may be made to disappear by using turpentine or benzine; although the former should not be applied to silks. Ink-stains, mil- dew spots, dye-stains and tar may be readily removed by the use of solutions No. 1 and 2 as above. Lengthening Life of Window Shades If glue, instead of tacks, is used in attaching a window shade to the roller, a much neater job can be done, and the shade will not be torn if it is accidentally pulled down too far.

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What 2 Woman Should Know About Electric Connections The average woman’s knowledge con- cerning the electric current which is sup- plied to her home is usually vague. When she goes to the stores to buy ap- pliances, the clerk often asks her whether the current is alternating or direct, and a surprisingly small number of women are able to answer correctly. This she should learn from the electrician or el- ectric company. Few women are able to replace a fuse which has burnt out, and spend dark hours waiting for an electrician to repair the slight damage. She can buy fuse plugs for a few cents and can replace them herself. The mica top of the or- dinary fuse plug shows at once which one is burnt out. Many stenographers are able through long practice to. become most familiar with the various types of typewriters, and are able to make slight repairs when their machines are out of order, but should you ask her a question as to the voltage or current in her home, she is unable to answer intelligently. The simplest method of acquiring a little knowledge of this subject is to read the information plate which will be found on the meter. This gives valuable in- formation in regard to the voltage, the size lamp that should be used, and other facts that every woman should know. Leatherette Book Covers With a little ingenuity, some leather- ette upholstering material, glue, and a squeegee roller, very neat looking, handy, and serviceable covers may be made for drawings, note-books and_ snap - shot photograph albums. The cover may be made best on the loose-leaf note book principle, or may be made to cover a paper-bound book. By studying how any book is bound, it is easily seen how to go about making the cover. When it has been shaped and glued, the whole should be placed between two smooth boards and clamped for 10 or 12 hours. Fire Extinguisher Liquid Calcium chloride 30 oz.; salt 5 0z.; water 75 oz. Mix and fill thin spherical bottles with the liquid and seal. Dash the bottles into the fire. 2 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 821 Gas Heated Steam Radiator How the ordinary steam radiator can be converted into an independent heat- ing unit, thus eliminating expensive boil- ers and piping, is shown in the accom- panying illustration. The radiator is combined with a heater designed to burn artificial or natural gas which is fed into the burner beneath the radiator from the regular gas mains. A few quarts of water are poured into the radiator through an opening provided for the purpose, and a short while after the burner is lighted, the water is converted into steam. The two end sections of the radiator, which extend beyond the heat- ing area of the burner, act as condensers for collecting the water and returning it to the reservoir at the base. By means { “i % XJ 5 a ao he 4 Speers a ” | | QS How to make an excellent gas heater out of an ordinary steam radiator of the thermostat shown at the left, the pressure can be regulated within the limits of five and fifteen points. Thus, when the pressure of the steam reaches a certain point, the valve supplying gas to the heater automatically diminishes the size of the flame in the burners. As each heater in this scheme is independent of the others in the house, one tan heat any room at any desired time. A Handy Whetstone The carbon from a dry battery can be used as a whetstone and will give a very fine edge. A suitable handie may be placed on the brass screw which is found on the end of the carbon.

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eee aed te: nen sect ane 822 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Damper Opened Automatically by an Alarm Clock An automatic damper regulator may be constructed at home which helps avoid the trouble of attending to the steam heater when it is necessary to turn off the draft. An old alarm clock, or one that can b purchased for less ‘ than a dollar, onde forms the princi- i Z pal and acca o0voo000000000 = pensive part in an ‘ve the mechanism. S fh In fact, as may be rit f * 2 seen from the drawing, the only other materials re- quired are two medium sized spools, a small pulley, a few feet of picture wire, some small iron wire, several pieces of board and a few nails and wood screws. The first step is to fasten a spool to the alarm spring stem in place of the hand key. Hollow out the spool at one end in order to form a square cavity of larger diameter at the inner end than at the outward extremity. This cavity must be of a depth sufficient to receive the pro- jecting shaft of the alarm spring, the size of which can be measured by re- moving the hand key. A reasonable al- lowance of space is also necessary for the hot lead which will have to be poured into the spool around the shaft in order to connect the two parts rigidly. As soon as the spool is ready, a wash- er of felt or leather is cut out and placed over the projecting stem of the alarm spring close to the clock case. The clock is then turned over on its face and the spool put in position over the extremity of the shaft, and sufficient lead or other suitable solder is poured in through the upper end of the spool around the shaft. After the lead has hardened, the washer should be cut away as otherwise it would act as a brake on the spring. As a necessary precaution a loop of small iron wire may be passed around the spool at its inner end and twisted around as shown in the illustration. This will prevent the spool from splitting. One extremity of the wire is bent in the form of a hook which will be connected to the end of the wire which actuates the damper and the other end of the wire loop will be forced into the spool in or. der to keep it steady. When once the clock has been prepared, a wooden clam may be used to fasten it to the lever, The clamp in question can be made as follows: Cut a strip of board of about 7%", large enough to overlap the diameter of the clock, approximately 2” on each end, shape the board in U form for set- ting the clock in it. Also prepare a small strip of about 4” stock cut to the same dimensions as the U-shaped board and drilled with a hole at each end to take wood screws about one inch in length. A little hole is next bored to permit the wire from the damper to pass. When mounting the clock on the steam regulating lever, space should be allowed to permit easy access to the main-spring, winding key and setting key. The clamp must be so fastened around the clock that its front end will be below the lever while its rear end will be above. To connect the apparatus to the dam- per a loop is made on the piece of pic- ture wire which will be slipped over the hook on the winding spool and passed down through the hole in the binding strip, thence around a pulley on the front damper and up to the end of the steam regulating lever. A small spool should nUNUULAMt: ! ll { | | i iH} NN \ Fig. 1—Arrangement of alarm-clock damper regulating scheme

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be put on this wire and several loops made in the wire at a point just below the clamp which must be determined by trial. By passing a nail through these loops in the wire the spool will act as a stop and prevent the clock from open- ing the damper more than the required amount previously determined.

To Drain Underground Pipes An acetylene gas plant utilized for light- ing a house is located in a small detached building. The main gas pipe runs from the machine under the ground, passing beneath a cement walk, and then up to the house, forming a large U. The lights burned very poorly, and it developed that water had entered the pipe. Since no drip had been put into the pipe, it would have been necessary to tear up the con- crete walk to open it, but this difficulty was overcome as follows:

Openings in the gas pipe at its lowest point enable one to clean the pipe with no trouble A hole was dug near the gas house in the earth which covered the pipe, and a hole was drilled completely through the pipe. This allowed all the water to escape. The hole was then tapped and two bolts were screwed into the holes at the top and bottom. The work was only a matter of fifteen or twenty minutes and the pipe can now easily be drained at any time, with little excavation and no work on the pipe. This device is thor- oughly practical and an important aid to the home worker. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

823 To Discourage Prowling Cats and Dogs No more need people be bothered with troublesome dogs and cats upsetting rub- bish or garbage cans. The shocking de- vice shown in the picture will stop this trouble permanently. The base is made of a circular piece of wood with a margin of about 9” 10 volt circuit

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The encircling plate completes the circuit when a cat reaches to open the garbage can around the can. A circular space is cut out in the middle 34” deep, and slightly larger in diameter than the can. At the bottom of this hollow is placed a zinc plate with an iron rod soldered to the middle of it. The rod runs through a hole bored in the middle of the base; this is for the ground current. The rest of the base is covered within 1” of the can with zinc which has a binding post .at- tached to it. When the device is set up, it is placed on damp ground, or else a wire run to a water pipe underground has to be used to attach to the iron rod. The rod is then driven into the earth. A line is run from one wire of the house lighting cir- cuit to the binding post, using a switch between at some convenient place to shut off the current in rainy weather. A dog or cat must put its front feet on the encircling zinc. When it touches the can it completes the circuit and re- ceives a shock. It will not injure the animals in any way. A person can not get a shock unless he deliberately wets his feet and stands on the encircling plate. No electricity is used until some animal closes the circuit as described.

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; ease Sweets 824 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Closet Converted Into Magazine Case A closet which is not in use can be easi- ly converted into a convenient library for magazines. The panels of the door should be chiseled out carefully, together An old closet makes an attractive bookcase with the inside molding. The four inner corners should be braced with metal “L’s.” A section of clear window glass may be fitted into the door from the in- side. Space between shelves for stand- ard sized magazines should be a little more than 12”. The magazines are al- ways readily accessible. A Simple Waterproofing An excellent waterproofing substance can be made by mixing the following substances in these proportions: Milk, 10 parts. Flour, 4 parts. Molasses, 5 parts. Wood alcohol, 2 parts. How to Remove Indelible Ink Wet the stained portion of the mate- rial with chloride of lime and afterward rinse in a little ammonia or sodium hypo- sulphate and water. Three Ingenious Door-Checks GOOD door- ” stop may be easily made from a piece of clock or phonograph spring about 8” or 10” long, or even less. Use a small punch in making a hole in each end of the spring, which may be fastened by small screws or nails at the point where the door strikes the wall- board. After fastening one end, bend or bow the spring slightly before fastening the other end, thus making the middle of the spring protrude from the wall so that it is struck by the door first. The above arrangement has been found to be very satisfactory, as it keeps the door-knob and other parts of the door from injuring the wall. For another simple door - check, take a ‘re | spool (large or smal), sates according to use re- quired) and cut along the lines marked (+). Trim both top and bottom from front end only a small piece from rear end at the bottom, as per sketch. This will be found a very simple door-check, and may be painted to make it inconspicuous. An_ excellent door-stop, which combines both durability and in- e X pen Siveness, can be made out. of the ordinary track spike. It forms a solid im- movable stop, as shown in the sketch; and although it is recommended for use on concrete floors, it may be also adapted, by wrapping it in felt, for use on wooden floors as well. To Make Lacquer for Brass A useful and durable lacquer for brass on electrical instruments can be made by dissolving as much celluloid as possible in a small amount of banana oil of the kind used for gilding purposes.

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Stationary Ladle for Dipping Wires For dipping wires and small objects in molten lead or other metal, the station- ary ladle shown in the sketch has been used by a western experimenter. A 2” iron cap, such as is used to close up gas pipes, is attached to the wall by means A simple stationary ladle for dipping wires is made rom ordinary supplies, chiefly old gas pipe fittings of a %" iron pipe and flange. The hole for receiving the supporting pipe is drilled in the side of the cap close to the top. A Bunsen burner or the fittings of an old Welsbach mantle will serve very well as the heating element, and a cone- shaped piece of tin slipped over the burn- er will bring the flame near the bottom of the receptacle, as well as protect the flame from gusts of air. It will serve, in addition, to concentrate the heat. _A small ladle for hand use can be similarly made from a 3%” gas cap, into the side of which a rod and handle should be screwed. 825 For Practical Workers Repairing a Starting Box With a Lamp The starting-box shown in the illus- tration had a defective series coil in the no-voltage release. Repairs were re- quired immediately ; and inasmuch as no new coil was then available, a 25-watt 220-volt tungsten lamp was inserted in series with the magnet coil as shown in the figure. The lamp gave a resistance of 1,947 ohms, and the defective coil’s resistance was 1,800 ohms. Thus the lamp did not heat the magnet coil; while at the same time it furnished light for the shop. Utilizing an incandescent lamp to repair a defective series coil

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sense SS RNR ONE SNNN 826 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Generating Gases in Large Quantities There have been described from time to time in these pages, many pieces of apparatus for generating gases such as hydrogen, sulphureted hydrogen, etc., but only for comparatively small quantities or for individual use. The one about to be described is suitable for a busy labora- tory. The apparatus need be charged but once a month, or, if for private use, once in two or three months or even less often, according to the amount of gas used. In the figure A and B are two aspira- tors, or bottles, with an extra neck at the bottom. A can be raised up to C or placed on a table at D. B contains a layer (E) about 2 inches deep, of broken glass or stones, or, in fact, any substance not affected by the acid. The top layer (F) consists of the substance to be acted upon, viz., sulphide of iron. The bottles A and G are filled with diluted hydro- chloric acid (1:3). The advantage in this apparatus lies in the addition of the bottle G, which makes it possible to use very much more acid and to charge less frequently than would be the case if A and B were di- rectly joined. When the apparatus is not in use it is advisable to lower the bottle A to the bench, although not ab- solutely necessary. The foregoing description is for the Large quantities of gases can be generated without continued attention by means of this home made apparatus generation of sulphureted hydrogen gas but the same apparatus will serve equally well for the following gases: Hydrogen. Dilute hydrochloric acid in A and G and zinc or iron at F. Carbonic Acid Gas. Dilute hydrochlo- ric acid in A and G and broken marble chippings at F. Nitric Oxide. Dilute nitric acid (2:1) in A and G and copper scrap at F. A Tool for Bending Tubing A device for bending tubing and pipes is show in the illustration. Two sheets of iron 1%” thick are bent as shown, and riveted together at their lower ends, Across the top should be riveted a piece of sheet iron of the same gauge as the A simple but rigid and effective tool for bend- ing tubes and piping other two, and having a slot running lengthwise wide enough to admit 3” bolts. A set of grooved wheels are now to be made up of the size required for the particular needs. Each wheel is fur- nished with a 3%” hole, so as to admit the bolt which is to fasten it to the slot- ted plate. The bolts should be long enough to extend from beneath the face place, through the slot and the wheel, and to project about 34” above the wheel. The latter can now be made secure to the plate by means of a nut, and the whole tool gripped in a vise at its lower end. When the tool is thus in place in the vise, and a wheel fastened to the plate, tubing or piping can be readily bent around the grooved wheels. Show Card Ink A good ink for show card writing can be made of asphaltum, 2 oz; venice tur- pentine, 1 oz; lampblack, % oz, oil of turpentine, 8 oz. Mix well.

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HHome-Made Worm Wheels and Screw The amateur mechanic who frequently requires a worm wheel and screw can easily construct this apparatus from readily obtained materials. First pro- cure a brass disc of the proper thickness and of a diameter a trifle larger than the finished wheel. After drilling the hole for the shaft, lay the disc on the flat end of a lathe-tool, and screw it to the tool so that screw fits snugly in the hole, permitting the disc to turn freely with- out any lost motion. Now take a tap, E, of the required pitch and insert it in the drill chuck of the lathe, so as to bring the disc against the tap. By manipulat- ing the feed screw of the slide rest, the tap will gradually cut a thread on the edge of the disc as the latter revolves. To make the worm screw, take a piece

A worm wheel and screw made from readily obtained materials of piano wire of the proper thickness and wind a close spring, F, that will just fit over the shaft. Then stretch the wire so that it will have the same pitch as the tap E. When cut to the required length and mounted on a shaft, the wire makes an excellent worm-screw.

Cushion Spring for Compasses A very useful kink for a draughtsman is shown in the accompanying sketch. It is often found that a bow pen or pencil, especially one that has been used for considerable time, will not spring open quite as far as desired although the ad- justing screw is fully slackened and no amount of bending or springing seems to help matters. If, however, a small piece of rubber about 14” x 3/16” x 3/16” is cut from an ordinary pencil eras- er and forced up between the legs of the compasses where they join at the top they will be forced out some distance, POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

827 the rubber acting as an auxiliary cushion spring, which, while giving the compasses a capacity for drawing larger circles, in no way interferes with its use for small work.

A simple auxiliary compass spring made from a rubber eraser

An Open Circuit Telegraph System In building a telegraph line with a friend, the writer desired to use an open circuit system operating on dry batteries. After numerous experiments he devised the method shown in the diagram be- low. The line is of the ground-return system. One terminal of the battery is connected with the line, and the other is connected with the key, which leads to the ground. The sounder is connected with the ground and the line. In using a Eureka combination tele- graph set, the wiring below must be altered, as in the diagram. The cir- cuit switch should be removed from the key, as it is unnecessary, and if acci- dentally left closed would exhaust the power of the battery. An extra binding post is added. Wires are run from the sounder to the line and the ground and from the key to the ground, while bat- tery wires are connected with the line and the key. The advantage of this system are ap- parent. The use of dry cells in place of wet batteries is much cheaper, cleaner and simpler. Either party may call at any time. There is no switch to handle when changing from receiving to trans- mitting and vice versa. No battery is used at the receiving end, the current coming altogether from the sending station. | system =

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828 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Substantial Top for Work Bench Heavy carpentry and machine work requires a bench built rigidly and solidly. The legs may be braced easily enough, but a solid, enduring top cannot be im- provised. ‘By the use of maple flooring and old two-inch boards a very substan- tial work bench top can be constructed. Sufficient two-inch clip such as are attached to trouser hang- ers. Drill a hole, a little larger than the diameter of the tripod leg, through the piece of brass rod; then drill two addi- tional holes at right angles so as to meet the first hole. Solder a small hexagonal nut over one of these latter, and screw a small wing-bolt into the nut. Solder planks of the correct length should be se- cured, and these should be glued and doweled together to form the desired width. When the glue is dry, the bot- toms of these planks should be cut out to ad- mit the strips, D and D1. They should then be glued and securely screwed to the planks C. The two-inch boards edging the bench-top should be trimmed with saw and plane on the edges and strips of the half-inch maple flooring nailed along them. Next the strips of flooring, E and E’ should be nailed to the two-inch planks with the grooved edge toward the inside. The flooring should be laid length- wise starting with the piece F. As flooring is supplied with only one end tongued, the other end must be tooled to fit the grooves of the cross pieces E and E*. When the floor is laid, it should be planed smooth and sandpapered. It should be finished with two coats of boiled linseed oil and two of shellac. Helps for the Chemist For steadying a retort on a tripod, a spring attachment as shown in the sketch can be easily constructed. Procure a piece of square brass rod about 3%” long, a foot of springy wire, and a wooden Simple helps for the chemist Details of the construction of a work-bench top the wire into the hole drilled lengthwise, as shown in the diagram. Make a de- pression in each jaw of the clip and glue a piece of felt to each depression. Then solder the clip to the other end of the wire. Slip the small brass rod over the leg of the tripod and fasten the clip to the retort tube, after tilting the latter to the desired angle. The spring wire will hold the retort firmly against jar and vibration. Frequently a siphon ceases to flow at the critical moment. This difficulty can be guarded against by inserting a small glass tube bent as shown into the stopper, and providing a rubber bulb at its outlet end. By squeezing the bulb several times, the siphon will readily start again, a scheme worth all its trouble in making. To Mark Gauge Glasses Neatly In all places where gauge-glasses are seen, one often sees two or three strings tied around the glass. This means of ’ telling accurately the reading of the gauge is unsightly and gives an appear- ance of inefficiency. A much neater and more business-like appearance may be secured by taking rubber washers and placing them on the glass. These may then be slid up or down. Nv ae am A Alt OK OF St Ss Ht OTD

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HE amateur workman and experi- menter who uses tools such as screw-drivers, cold chisels, etc., often finds that some of them need to be retempered, as with the best of care some will prove too hard for the average run of work, and a piecewill breakout. Anyama- teur by following these instructions will be able, with a little practice, to temper a cold chisel or a screw-driver so that it will give good service. Those who do a little blacksmithing and forging can also make many articles and give them the proper temper for the work they have to do. If a tool has a fair-sized piece broken out, it will have to be annealed first. This is best done by heating it to a cherry-red color and then burying it into ashes or lime, making sure that they are dry. Cover the tool completely so that no air can get to it. Leave in the ashes for 24 hours, or until cold. Take out and grind on an emery wheel or a grind- stone to the shape desired, having the cutting edge ground ready for service. Before a tool can be tempered it must be hardened. This is done as follows: The tool is put into a coke, soft coal or a hard coal fire, as may be convenient. Turn over occasionally so as to heat it evenly. When it is a cherry-red color, take out of the fire with a pair of tongs (which may be bought cheaply at any hardware store) and plunge into a two-gallon crock containing salt water, enough salt being added to the water to make it taste strongly. The tool should be held in a vertical position to avoid warping when put into the water for hardening, and moved around in it until cold. It also should be plunged only half-way into the solu- tion, thus leaving the shank hot, while the point is cold. After hardening, rub the point or edge with a file, a piece of firebrick, or a piece of emery cloth tacked on a block of wood. This is done so the color can easily be seen, the color travel- ing from the hot shank towards the point. When the desired color reaches the point the tool is then completely sub- merged in the salt water. Hardening and Tempering Steel Tools 829 The tempering colors follow, each representing a lower degree of hardness than the preceding. Straw color is the hardest, then comes brown, light purple, dark purple, deep blue and pale blue. Straw color is suitable for cold chisels where there are very light blows struck, or for other work where great hardness is desired. Where heavy blows are struck, it is best to temper the chisel to brown. Screw-drivers should be col- ored a light purple, and springs or other articles that do not require to be very hard, a deep blue. If desired, the tool after tempering may be polished with oil and fine emery paper. When the hot metal is plunged into the salt water bath for hardening it will make a snapping sound. The salt, besides making the steel very hard, also cleans it from dirt and scale left by the fire, the tool having a silvery-white color when withdrawn from the solution. There are a number of different chemi- cals used by blacksmiths for hardening, among them being cyanide of potassium, which is a deadly poison and should not be used by amateurs. The plain salt bath will be found to suit all amateur requirements ; in fact, a large number of professional temperers prefer it to the cyanide solution. The foregoing instructions for temper- ing tools are for the bought article dam- aged by use. To the embryo blacksmith who desires to make his own cold chisels, etc., purchasing the steel necessary for the work, it must be pointed out that steel bars are made containing different amounts of carbon, and as the latter ele- ment confers the property of hardening and tempering upon steel tools, it will be advisable to select a metal having a suitable carbon content. From .9 per cent. to 1.1 per cent. car- bon will be found to be best for all- around work. Here is a list showing the amount of carbon desirable in steel for various work: .5 per cent. carbon for battering tools, .7 per cent. for hot work, .8 per cent. carbon for wood-cut- ting chisels and some forms of reamers, .9 per cent. carbon for cold chisels, drills, taps, dies, and reamers, 1.25 to 1.58 per

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830 cent. carbon for lathe tools, graving tools, scribers, scrapers and small drills. Steel containing low amounts of carbon, such as .15 per cent., will not temper. The amount of carbon in the bar has to be suited to the work to be done when made into tools. Thus, a high-carbon steel crowbar of 158 per cent. carbon, no matter how catefully tempered, would be brittle com- pared to a crowbar made of .9 per cent. carhon steel, the latter being able to with- stand far more rough usage and give better service than the high carbon one. The amateur worker in steel can get con- siderable enjoyment as well as instruc- tion by gempering the tools that he works with, experience proving that it will al- ways come in handy when anything goes wrong with tools, which sooner or later, always occurs with the best in the market. Adjustable Drawing Trimmer A simple and easily made drawing plate trimmer is shown in the illustra- tion. A safety razor blade is clamped to a suitable handle of POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Cross Cutting Gauge for Band Saw A band saw may be used for cross- cutting light lumber if the attachment shown in the accompanying drawings is employed. The supports B are pivoted at both ends and the stock E put in place as shown. When the supports and How a band-saw can be guided to cross-cut light lumber stock are swung slowly upward, the saw cuts through smoothly and accurately. wood, the slot at A, as indicated by the dotted Sotely razor me line, is to permit the angle of the cutting edge to be changed at will. The width B, of the cut- ting edge, must be ad- justed according to the thickness of the tee- square that is being used as a straight edge. o> q S SS UL “lot in wood Aqjusting screw A safety razor blade can be made into an excellent draftsman’s cutter A Handy Reamer An old file or rasp will often be found handy in the workshop to ream holes in wood or metal. When the hole desired is not too large, the end of the file may be put into a brace, and the pointed end used as a reamer. For larger holes, re- verse the ends of the file in the brace. Reaming from both openings will im- prove the quality of the hole consider- ably. After reaming, the holes should be finished with a fine rat-tail file. To Tap a Hole in a Corner A hole in a corner can be tapped by the use of a ratchet brace. The pivots, C, C, should be bolted to the saw table at a sufficient distance from the teeth, so that the back is not cut through. Cement for Mending Steam Boilers Mix two parts of finely powdered litharge with one part of very fine sand, and one part of quick lime which has been allowed to slack spontaneously by exposure to the air. This mixture may be kept any length of time. In using it a portion of it is mixed into a paste with linseed oil or, better, boiled linseed oil. In this state it must be quickly applied, as it soon becomes hard.

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ANY car owners recognize the value of having the car overhauled be- fore the inception of the active riding season, when climatic conditions are not favorable to the continual operation of the car. In those portions of the country where cars may be kept in operation all the year round, a certain time each year should be set apart for giving the car a thorough looking over with a view of de- termining the points where depreciation exists, and best Overhauling Your Car for the Winter By Victor Pagé is dismembered, in most cases by re- moving the bottom plate, thus exposing the main bearings and crankshaft. The first operation is the removal of the in- let and exhaust manifolds, next one un- couples the water piping from the radi- ator. There are various methods of fastening manifolds on the cylinder cast- ing, the most common being by retain- ing stirrups, or by flanges and bolts, as outlined. in illustrations of engines at methods of rem- edying the de- fective condition. The wise motorist realizes that this work of restoration is absolutely neces- sary if continued satisfactory service is to be expected from the car. The motorist who shuns the expense of hav- ing the machine looked over, and who operates it as Fig. 1. As will be evident, where cylinders are of the T-head form, with valves on opposite sides of the cylin- der casting, the bolt and flange sys- tem is generally used. On L-head motors, where the valves are in the same extension of the cylinder cast- ing, the bolt and stirrup _ retention Breather Pipe Wiring Conduct long as the various parts function, is generally the one who is loudest in the condemnation of the automobile. In this article the writer discusses various steps inci- dental to overhaul- Induction Manifold Carburetor method is generally followed. One may safely say that en- gines of low and moderate - priced cars, being of the L-head form, will have the manifold retained by stirrups and bolts, whereas Magneto inggasolineengines Fis: |. of various types. In taking down a motor the smaller parts and fittings, such as spark plugs, manifolds and wiring, should be removed first. Then the more important mem- bers, such as cylinders, may be removed from the crankcase to give access to the interior and make possible the examina- tion of the pistons, rings and connecting rods. After the cylinders are removed the next operation is to disconnect the connecting rods from the crankshaft and to remove them and the pistons at- tached as a unit. Then the crankcase Exhaust and intake side of locomobile four-cylinder motor the T-head power plant of the larger and higher-priced cars will use the bolted manifold con- struction. It is now common practice to cast all cylinders together, blocks of four being very common and blocks of six are not rare enough to cause comment. In some cases the manifolds are cored integral with the cylinder casting, and it is merely necessary to remove a short pipe leading from the carburetor to one inlet open- ing and the exhaust pipe from the outlet opening common to all cylinders. In order to remove the carburetor it is

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832 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE necessary to shut off the gasoline supply at the tank and to remove the pipe coup- ling at the float chamber. It is also necessary to disconnect the throttle operating rod. After the cylinders are removed, and before taking the crank- case apart, it is well to remove the water pump, magneto, and mechanical oiler if that system of lubrication is used. The Wiring on most engines of modern de- velopment is carried in conduits, and usually releasing two or three minor fastenings will permit one to take off the pin or crank pin ends, and also to form some idea of the amount of carbon de posits on the piston top and back of the piston rings. Any wear of the timing gears can also be determined. The te. moval of the bottom plate of the engine enables the repairman to see if the main bearings are worn unduly. Often bear. ings may be taken up sufficiently to eliminate all looseness. In other cases they may be worn enough so that care- ful refitting will be necessary. All engines are not of the type shown plug wiring as a unit. The wire should at Fig. 1. Where the crankcase is dj- be disconnected vided horizontally from both spark into two portions plugs and magneto /nlet the upper one serv. distributor before Manifold ing as an engine its removal. The A base to which the appearance of the cylinder and, in engine shown at 3 \a fact, all important the bottom of Fig. ° ° working parts are 1, after the mag- “ Fs attached, the lower neto ignition wir- : portion performs ing, spark plugs the functions of an and front of timing Carburetor oil container and gear case are re- ~ cover for the in- moved, is shown at Fig. 2, B. The next operation in dismantling this engine is to take off the four nuts holding the induc- tion manifold to the cylinder cast- ings and when the manifold is_ re- Cylinder Blocks ternal mechanism. There is a tendency on the part of mod- ern designers to combine the cylin- ders and a portion of the crankcase in one casting, using a detachable cylin- der head construc- moved the carbu- Fig. 2. retor comes with it. The appearance of the engine after this has been done is shown at Fig. 2, B. The next parts to be taken off, the cylinder castings, are shown in this view. Before disturbing the arrangement of the-timing gears it is important that these be marked so that they will be replaced in exactly the same relation as intended by the engine designer. If the gears are properly marked the valve timing and magneto setting will be undisturbed when the parts are replaced. When an engine has been taken down it is impossible to ascertain if there is any undue wear present in the con- necting rod bearings at either the wrist parts when dismantling power plant tion in order to Illustrating steps in removing motor Permit valve grind- ing and carbon re- moval without tak- ing the engine out of the chassis frame. The connecting rods and pistons may also be removed where this construction is followed through the opening left after the detachable cylinder head is removed. The important parts of an engine of the conventional four-cylinder pattern, where the cylinders are cast in pairs, are clearly shown at Fig. 3, and their ap- pearance may be readily noted. It will be evident that when the bottom of the crankcase is removed the crankshaft 1s exposed, and the main bearing caps may be released by unscrewing the bearing cap retention bolts. In some multiple cylinder engines the

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inders are cast individually, and in- = of the crankshaft having three main bearings, as is often the case, it has five main bearings, as indicated in the sectional view of the Overland en- gine shown at Fig. 4. When the cylin- ders are cast individually it is possible to replace a defective cylinder without sacrificing the remainder, as is imperative if the cylinders are cast in block. Indi- vidual cylinders are more easily handled, but where these are used it is absolutely necessary to mark them so that they will always be replaced in proper position. In most cases the cylinders are duplicates of each other, and if they were not marked it would not be difficult to trans- pose them on the engine base, an unde- sirable proceeding. - One of the most widely used of auto- mobile power plants, and one that prac- tically all repairmen will have occasion to work on at some time or other, owing to the thousands in use in all parts of the world, is that employed on the Ford Model T automobile. This power plant is shown in part sectional view at Fig. 5. It is a unit power plant, as the planetary change speed gearing is carried POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 833 in an extension of the engine crankcase. The four cylinders and upper portion of the crankcase are cast as a unit. The cylinder head is removable. One of the novelties of construction in this motor is the use of a flywheel magneto, the bal- ance member carrying a series of U- shaped magnets which revolve past a series of fixed field coils attached to a plate which does not rotate on account of being bolted to the engine crankcase. The general construction of the engine may be readily ascertained by careful inspection of the illustration. Defects in Cylinders——After the cyl- inders have been removed and stripped of all fittings they should be thoroughly cleaned and then carefully examined for defects. The interior, or bore, should be looked at with a view of finding score marks, grooves, cuts or scratches in the interior, because there are many faults that may be ascribed to depreciation at this point. The cylinder bore may be worn out of round, which can only be determined by measuring with an in- ternal caliper or dial indicator even if the cylinder bore shows no sign of wear. The flange at the bottom of the cylinder Rear Bearing Cap Retention Bolt Fan Driving Pulley. Valve Pushrod Guides Cam Shaft Bushings Cylinder Retention Bolts of Crankcase Serves as Oil Pan QO in Driving Gear Supporting Arm Bearing Cap Bearing Cap | a ‘Valve Pushrod Guide Fig. 3. Views of a partially dismantled automobile enzinc

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834 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE by which it is held to the engine base may be cracked. The water jacket wall may have opened up, due to freezing of the jacket water at some time or other, or it may be filled with scale and sedi- ment due to the use of impure cooling water. The valve seat may be scored or pitted, while the threads holding the valve chamber cap may be worn so that the cap will not be a tight fit. The cyl- inder described is an individual casting of the L-head form having integrally cast water jacket. Other forms of been evolved, one of two sheets of very thin, soft Copper bound together by a thin edging of the same material and having a piece of sheet asbestos interposed, solved this problem, One of the first engines tc use the de- tachable cylinder head piece was the Ford, and at the time it was first intro- duced it was met with considerable criticism on the part of automobile ep- gineers. That this proved unfounded and based on personal btrejudice js clearly demonstrated at this time by the wide use of the detachabie head con- struction. | Copper - asbestos packings form an effective seal against leakage of unit cylinders have of the most widely used being that of water and a posi- the four-cylinder ° Cadillac engines. This incorporates several novelties in construction, one being the applied sheet copper water jacket, the other being the detach- able cylinder head casting which is screwed down’ against the top of tive retention means for: keeping the explosion pres- sure in the c;lin- der. The great advan- tage of the detach- able head is that it permits of very easy inspection of the piston tops and combustion cham ber interiors, which the copper water jacket and held in can only be done with cylinders of place on the cylin- der by an external- ly threaded close nipple. An advan- tage which is being claimed for this construction is the easy replacement of one defective cylinder as- sembly part without scraping the rest. With the Cadillac construction, should the water jacket be faulty it is impossible to repair this easily, owing to the material employed, or to replace it if repairs are not practical. If the cylinder should be scored, the water jacket and combustion head may be saved and a new cylinder casting purchased at con- siderably less cost than that of the com- plete unit cylinder. The detachable head construction has only recently become popular, though it was one of the earliest forms of auto- mobile engine construction. In the early days it was difficult to procure gaskets or packings that would be both gas and water tight. The invention of the cop- cylinder _ castings per-asbestos gasket, which is composed Fig. 4—Longitudinal view of Overland four- cylinder motor, a type and a crankshaft the L or T form by removing the cylin- der from the en- gine base. Two forms of remov- able cylinder heads are shown at Fig. 6. They are similar in design and utilize the same form of gasket, the only differ- ence being that the type shown at A serves two cylinders, while the one out- lined at B covers the four cylinders. The construction at A is used on the Oakland car, while that at B is found on the Ford, Metz, Regal, Carter-car, Max- well, Oakland and several others. The cylinder heads are securely held by sub- stantial retention bolts, and if these are properly tightened and the gasket is in good condition there is not likely to be any loss in pressure due to leakage. One of the most important things to look for when the cylinder has been removed or the cylinder head taken off, if that method of construction is followed, is carbon deposits. These accumulate at the piston top, valves, around the spark having individual five-bearing

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- oe OE eS. eee, ee ae ee COU | OO eeellUlU ee CU POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Magueto Ooi) Support Primary Contact Magneto Ooi! Magnets Transmission Gears High & Slow Pedal Cylinder Head Piston Brake Pedal Reverse Pedal Transmission Cover Doo Transmission Bapd- Orank Oase Oi] Plug Orank Shaft Rear End Bearing ; Orank Shaft Conuecting Rod Piston Pin Piston Pin Brass Bushing’ | im: aay 31) 6 ! | | | i | ily: ry 1m Mer Clutch Finger: entice | ne | Clutch Lever = : IK ll one Shaft es x MIU a UU gs == 1 eat, us \ahil AG 4s ne Ni i Na MU Com mutator Orank Oase Transmission Shaft Oylinder Casting Oylinder Cover (Front End) Valve Spring Orank Oase Drain Oocks Valve Stem Cam Shaft Push Rod Top Water Connection ‘Water Jacket Exhaust Pipe Inlet & Exhaust Pipe Olamp Intake Pipe J = ; “s 4 al ra] : ‘ie }+——-Valve Cover | = oe Pipe Fig. 5. Phantom view of the Ford four-cylinder unit power plant plug and at several points in the combus- tion chamber. Carbon Deposits, Their Cause and Prevention. — Most authorities agree that carbon is the result of imperfect: combustion of the fuel and air mixture as well as the use of lubricating oils of improper flash point. Lubricating oils that work by the piston rings may become decomposed by thé great heat in the com- - bustion chamber, but at the same time one cannot blame the lubricating oil for all of the carbon deposits. There is little reason to suspect that pure petroleum oil of proper body will deposit excessive amounts of carbon, though if the oil con- tains a resinous or animal fat filler there would be much carbon left in the interior of the combustion chamber. Fuel mix- tures that are too rich in gasoline also produce these undesirable accumulations. Fully 50% of this deposit can be at- tributed to the ordinary dust of the high- way and not to excessive fuel or an im- pure grade of lubricating oil. While it 1s imperative to use as little gasoline in the mixture as possible, and to supply only the proper quantities of high-grade lubricating oil, it will be evident that even if these precautions were carefully ob- served there would still be considerable deposit as the result of the impurities drawn in through the carburetor. It is very good practice to provide a screen on the air intake to reduce the amounts of dust sucked in with the air as well as.ob- serving the proper precautions relative to supplying the proper quantities of air to the mixture and of not using any more oil than is needed to insure proper lubri- cation of the internal mechanism. Use of Carbon Scrapers—It is not unusual for one to hear an automobile driver complain that the car he drives is not as responsive as it was when new after he has run it but very few months. There does not seem to be anything ac- tually wrong with the car, yet it does not respond readily to the throttle and is apt to overheat. While these symptoms denote a run-down condition of the mechanism, the trouble is often due to nothing more serious than accumulations of carbon. The remedy is the removal of this matter out of place. While the surest way of cleaning the inside of the motor thoroughly is to remove the cylin- ders, if these members are cast integrally with the head, or of removing the head member, if that is a separate casting, to

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886 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE expose all parts, there are other methods that have been recommended that may be depended on to reduce the amount of carbon deposits. A number of carbon solvents of a secret composition have been offered which may be introduced into the cylinder through the spark plug openings or valve cap holes that are said to soften the accumulation and permit it to be blown out through the exhaust when the engine is again started after the material is used. The writer believes that there is more or less “fake” about these compositions, employing cylinders of the T form. No claim can be made for originality of novelty of this process as it has been used for many years on large stationary en- gines. The first step is to dismantle the inlet and exhaust piping and remove the valve caps and valves, although if the deposit is not extremely hard or present in large quantities one can often manipu- late the scrapers in the valve cap open- ings without removing either the piping or the valves. Commencing with the first cylinder, the ‘starting crank is turned till the pis-

as chemical analy-

sis of some has dis- closed the composi- tion, which, on A careful study of ; cause and effect, does not seem to -justify all the claims made for them by the en- thusiastic advertis-

ton is at the top of its stroke, then the scraper may be in- serted and the operation of re- moving the carbon started by drawing the tool toward the opening. As this is similar to a small Head hoe, the cutting

ing men _ respons- ible for their pro- | 8 motion. One widely advertised carbon remover of liquid | _ form was found to |/stonzee be composed large- |7ops

GOSS edge will loosen some of the carbon Cylinder, and will draw it toward the open- ing. A swab is made of a piece of cloth or waste fast-

aa is <

ly of acetone. An- other was practi- cally deodorized kerosene and de-

ened at the end of a wire and well soaked in kerosene to clean out the

natured alcohol

cylinder. When the

mixture. Another of granulated form was discovered to Fig. 6. Showing utility of detachable cylinder heads and how they make for superior ac- cessibility of valves and combustion chambers engine is of a T-- head type and the valves are removed

be practically com- mont salt. There is no question in the writer’s mind but that a solvent like ace- tone would soften carbon deposits enough so it could be readily removed by scrap- ing. In certain forms of cylinders, espe- cially those of the L or T form, it is possible to introduce simple scrapers down through the valve chamber cap holes and through the spark plug hole if this component is placed in the cylinder in some position that communicates di- rectly to the interior of the cylinder or to the piston top. This method is par- ticularly applicable to engines having valves on opposite sides, namely those it is possible to in- troduce a ball of waste at one part and push it clear through the cylinder and out of the other valve port, this bringing much loosened carbon out with it. When available, an electric motor with a length of flexible shaft and a small circular cleaning brush having wire bristles can be used. Repairing Scored Cylinders—lIf the engine has been run at any time without adequate lubrication one or more of the cylinders may be found to have vertical scratches running up and down the cylin- der walls. The depth of these will vary according to the amount of time the cyl- inder was without lubrication, and if the

on th oes FF KH OLS OS 45

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grooves are very deep the only remedy is to purchase a new member. Of course, if sufficient stock is available in the cyl- inder walls, the cylinders may be rebored and new pistons which are oversize, 1. é., larger than standard, may be fitted. Where the scratches are not deep they may be ground out with a high-speed emery wheel or lapped out if that type of machine is not available. Wrist pins have been known to come loose, es- pecially when these are retained by set screws that are not properly locked, and as wrist pins are usually of hardened steel it will be evident that the sharp edge of that mem- POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 837 For this reason most mechanics prefer to fit either a new cylinder and piston or to rebore the cylinder and fit a larger piston with correspondingly larger rings. If the car is an old one and it is not considered wise to spend the money necessary to restore the cylinder bore to correct shape, one can get considerably more service by a simple expedient of making new piston rings with long stepped ends. In this case they will pass the smaller portions of the bore and ex- pand sufficiently to fill the worn parts. As there is no gap between the ends, even when fully expanded, there will be but little loss of com- ber can act as a cutting tool and make a pronounced groove in the cylin- der. Cylinders that have been damaged in this manner have sometimes been re- paired by the auto- genous welding process, the oxy- acetylene flame be- ing used to fuse new cast iron into pression, such as might be possible with. either butt joint or diagonal cut rings under the same _ conditions. One precaution is essential, however, and that is to insure that the grooves are of suf- ficient width to take step cut rings having substantial the groove, then grinding out the ridge of excess ma- terial in order to Fig. 7. Outlining use of dummy piston and connecting rod for lapping out fine scratches in cylinder bore steps. If the piston tings are narrow, the ends are apt to obtain a smooth bore. Cylinder grinding is a job that requires skilled mechanics, but may be accomplished on any lathe fitted with an internal grinding attach- ment. When a car that has been used for a considerable length of time is overhauled it may be found that the cylinder bore will have worn enough so reboring will be necessary. The wear is commonly found about midway the length of the cylinder walls, as it is at this point that the connecting rod side thrust is greatest, due to the angularity of that member. In order to remedy this defective condi- tion some repairmen are content with merely fitting new piston rings of slightly larger circumference, but this plan is not wholly satisfactory, because if the rings are of sufficiently small diameter to enter the unworn portion of the bore when they spring out into the worn part there must exist too wide a gap at the slots. snap off at the steps. If the grooves are turned out to a greater width, new piston rings must be made to fit. The compres- sion is much improved and power is increased as the rings with the long- stepped joint will follow the worn bore, constricting as the bore is smaller and filling out as the wear increases. Where the grooves in the cylinder are not deep, or where it has warped enough so the rings do not bear equally at all parts of the cylinder bore, it is possible to obtain a fairly accurate degree of fin- ish by a lapping process in which an old piston is coated with a mixture of fine emery and oil and is reciprocated up and down in the cylinder as well as turned at the same time. This may be easily done by using a dummy connecting rod having only a wrist pin end boss and of such size at the other end so that it can be held in the chuck of a drill press. The cylinder casting is firmly clamped

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8388 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE on the drill press table by suitable clamp- ing blocks, and a wooden block is placed in the combustion chamber to provide a stop for the piston at its lower extreme position. The back gears are put in and the drill chuck is revolved slowly. All the while that the piston is turning the drill chuck should be raised up and down by the hand feed lever, as the best re- sults are obtained when the lapping mem- ber is given a combination of rotary and reciprocating motion. Even if power is not available, the re- pairman need not be discouraged, because very good results may be obtained by hand lapping. The same method is used as for lapping by power. The abrasive material is composed of very fine emery and light machine oil, and is renewed from time to time and the cylinder cleaned out to remove the old lapping compound before any new mixture is in- troduced. A cylinder may be easily sup- ported in a box of sand, as indicated, the compression relief petcock in the top of the cylinder being provided with a piece of rubber hose which projects above the surface of the same, and which acts as a breather opening for escape of the air compressed by the downward stroke of the lap. Where the cylinders are cast in block, as is now common practice on nearly all automobiles of recent development, it is not difficult to hold the cylinder block, as this is of sufficient size and weight to stand upright on the bench without clamping it down. The process of lap- ping is continued until the entire interior of the cylinder is bright and clean and the scratches practically removed. All abrasive material is then washed out of the cylinder with gasoline and the walls wiped dry with a soft cloth. How to Repair a Cracked Water Jacket—The water jacket of a gas en- gine cylinder will sometimes become cracked, due to freezing of the cooling water, or perhaps as a result of a sand or blow hole which opens up from vibra- tion after the cylinder has been used a while. At the present time the usual practice in repairing cylinders is to fill the depression or crack with iron by the autogeneous welding process, although various iron cements may be used for that purpose if the fracture is not seri- ous. A mechanical repair is always pos- sible, i.e., a metal patch can be applied to cover the crack and held in place against a gasket interposed between the plate and the cylinder jacket by small machine screws tapped into the iron. Where only a small blow-hole exists or a small crack the mechanical method shown at Fig. 8 is possible. This consists of drilling a hole of sufficient size to take a standard pipe plug, either % inch or y, inch, according to the size of the hole, as shown at A. A pipe plug is screwed into the tapped hole, as shown at D, and when it has been forced in place after coating the threads with red lead and oil or pipe joint compound to insure a tight joint, the projecting portion of the plug may be cut off with a hacksaw as out- lined at Fig. 8, C, and the remaining portion of the plug filed flush with the outside of the water jacket. If the crack is of some length it may be repaired by the following method: On the line of the fracture drill and tap for a 3%-inch threaded copper rod. This rod is screwed in firmly to a depth about equal to the thickness of the metal of the water jacket. Cut off the copper rod with a hacksaw, allowing it to project about 1/32 inch; then drill succeeding holes, each hole being drilled partly into the previously inserted copper plug, so that when all of the plugs are placed in the cylinder casting they form a continu- ous band of copper along the line of the fracture. The copper plugs should now be peened down and trimmed off flush. The only possible chance for leakage, after having repaired the crack in this manner, is for the water to follow the joint between the metal of the jacket and the copper plugs, but as the copper rods are threaded into the casting, it is not likely to occur. Should leakage take place, a little extra peening will suffice to prevent it. Still another method involves fusing copper filings or granulated brass spelter into the crack. This has the advantage of not requiring the removal of the part to be repaired. Drill and tap a small hole at each end of the crack to prevent further extension of the weakness, and screw in an iron stud. Next clean the outside and inside of the fracture very thoroughly, using a scraper and gasoline. ret— 0 © FI =~ #4 © O35 ee |,

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ile up some soft copper or brass spelter ee an the crack, heaping the filings over it. Then take a powerful blow- lamp or a torch and direct the flame on the copper. By this method a fair amount of metal can be worked into the opening. After cooling the studs are cut off flush and the copper filed smooth. It is said that the repair will last. In many cases the crack may be closed by making a rust joint. The first step is to drill a very small hole at each end of the crack to prevent it from spreading and to drive in or screw in a metal plug in each hole. The ° POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 839 are in good condition. The gasket at the exhaust pipe should also be inspected. The packings for the inlet pipe may be of weil shellacked cardboard, mobiline or other asbestos packing, or even sheet rubber, but those used on exhaust pipes should only be made of asbestos or cop- per-asbestos. A defective gasket on the inlet manifold will seriously attenuate the mixture going to all cylinders, while a defective packing under the exhaust manifold joints will have no effect upon the operation of the motor, the only re- sult being a sharp hiss or whistling sound due to the leaky crack is then filled up with a paste made of 66% fine iron filings or iron dust and 33% sal- ammoniac in the pulverized form, with just enough water to make a mixture of proper consistency to be forced into the crack easily. The action of the sal- ammoniac is to rapidly oxidize the fine iron filings, producing rust which joins the various iron par- ticles together and effectively seals the opening when it has gas. Engines of the detachable head form have pack- ings that are made of a sheet of asbes- tos sandwiched be- tween very thin sheets of copper. While these pack- ings have the ad- vantage of not de- preciating rapidly, at the same time they may be packed down so solid and be so stiff that they will not allow the cylinder head to bed properly after they have _ been used for a time. Some _ cylinders, properly hardened. As a number of prepared cements for use with cast iron may be purchased at low cost, it is often cheaper to buy the cement than to attempt to make it. Inspecting Cylinder Head Packings. —On a number of overhead valve type motors having the valves carried in a re- movable cage gaskets are used to obtain a tight joint when the cage is screwed down. This packing frequently becomes soft, resulting in a leak around the valve. In multiple cylinder motors the gaskets that are used at the point where the in- take manifold joins the respective cylin- ders should be examined when the mani- fold is removed to make sure that these Fig. 8. Method of using pipe plug for sealing fine cracks or sand holes in cylinder water jacket especially of the in- dividual casting form, have a hole at the top which is used for holding the core during the cast- ing. This hole is usually filled with a plug : tightly screwed intoit, andthe orifice should be tightly sealed against internal pressure or water leakage. These plugs are some- times made of bronze, and it is not un- usual to find that they will leak slightly as they have become loose due to the difference in ratios of the expansion be- tween the iron used for the cylinder and the metal of which the plug is composed. If the cylinder is of this pattern, this plug should be looked over carefully. A number of cylinder designs, espe- cially those in which four or more cylin-

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ders are cast in a block, have a large plate at the side which is used to close the water jacket, this forming a cover for an opening which had been left to facilitate foundry work when the cylin- der was cast. This plate is either of sheet brass or aluminum; in some cases it may be an aluminum casting having a portion of the intake manifold cast with it. Leakage is prevented by a packing inter- posed between the plate and the cylinder. A Compressed Air Tank The acornmpany- ign sketch shows how a beer-keg, a pump, several pieces of piping, and a valve from an auto- ‘mobile tire were used to make a com- pressed air tank. Three holes were bored in the top cov- er of the keg. Into one was screwed a valve taken from the inner tube of a tire; and a gauge for indicating pressure was connected with the second hole by means of 14” piping. The third hole received the pipe and valve for drawing off quantity of com- pressed air required. Now, with the aid of a good bicycle pump, the barrel could be pumped full of air, just as a tire is ‘pumped up. The valve prevented the es- cape of air back into the pump. The keg contained 2” of water. A pressure of 150 Ibs. was obtained with this device. Prolonging the Life of the Storage Bat- te Ty When storage battery plates begin to sulphate, due to an accidental over- charge or over-discharge, their life may be greatly prolonged by removing the deposit of lead sulphate. This may be done as follows: First the cell should be fully charged and then the electrolyte siphoned off and pure water substituted immediately. The cell must now be discharged through a resistance, after which the plates may be removed. The white deposit of lead sulphate may now be removed with coarse sand paper, and the battery re- assembled with new electrolyte. 840 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE The lead sulphate, if allowed to re. main on the plates, will cause them to warp or buckle, and will eventually re. sult in an internal short circuit, and ruined plates. Simple Substitute for Bunsen Burner A simple but ef- fective substitute for a Bunsen burn- er, operated by car- bide instead of il- luminating gas, can be made from ma- terials* costing only a few cents. All that is needed is a medium-sized bot- tle with a large neck, a cork to fit the neck of the bot- tle, 4” of 1/16” — brass tubing, 4” of 3/16” tubing and the cover from a small baking powder can. The tin cover is intended to hold wa- ter and should be soldered to the smaller tubing so that when the tube is run through the cork, the water will drip down into the bottle. Six or eight small holes are drilled in one end of the larger tube, which is bent at an angle, and the other end of this tube also run through the cork. To operate the burner, fill the bottle about one-third full with carbide, such as is used in acetylene gas generators, put the cork in place, but not too securely, so that it will act as a safety valve in case the burner tube becomes stopped up, and fill the receptacle with water. Gas will immediately begin to generate and by holding a lighted match to the burner it will soon come to a steady flame. The pressure of the gas in the bottle will regulate the flow of the water. This little device may be used for any purpose for which the ordinary Bunsen burner is employed. It is especially use- ful in workshops where illuminating gas is not obtainable. Cement for Steam Pipes Good linseed oil varnish, ground with equal weights of white lead, oxide of manganese and pipeclay make a good cement for steam pipes.

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ewe C9 °° SS we Sl OO™.CUwY ao ta ™ A Home-made Tank Heater The illustration pictures a cement trough for watering horses and cat- tle. It is built on the outer wall of an engine house under a porch roof, which protects the cattle from the weather. Any water left in the trough freezes on cold days. ; In the engine house is a 2-h.p. gaso- line engine. The exhaust pipe has been run through a discarded hot-water tank and thence out of doors. By this means the tank is heated while the engine is running, perceptibly raising the tempera- ture of the room. This contrivance has been in constant service for two winters, and to this was made the addition which re- sulted in a heater for the outdoor trough. How the exhaust \ of a gasoline en- gine heats a watering tank To the exhaust pipe running through the hot-water tank, was added a suffi- cient length of old gas pipe to carry the length of the house overhead, down the wall and out into the trough. Here it connects with a rectangular pipe-frame which: rests on the floor of the trough, the return pipe with a double elbow car- rying off the exhaust at one end of the trough as in the diagram. This particular engine runs from 30 to 40 minutes, night and morning, to supply air-pressure for the water system and to tun the dynamo which furnishes electric- ity for the farm. At the same time the exhaust, carried through the described tank and pipes, warms the building and heats the water in the drinking-trough at the times when it is most needed. Cutting Stove Pipe Use a can opener to cut stove pipe if you have no large pair of shears. The can opener answers the purpose admir- ably. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 841 A Slotted Screw Driver The sketch shows a method of adapt- ing a screw driver so that it can hold a screw while being handled. The mag- This slotted screw driver seldom drops a screw netized screw driver is often inefficient; besides being useless for brass screws, it loses its magnetism after a little use. By slotting an ordinary screw driver, however, a certain amount of spring is obtained; and when the two prongs are inserted into the head, the screw is very firmly held. To Find How Long Hammer Handle Should Be A very simple way to get the length of a hammer handle which a machinist should use to get the best results is as A hammer handle should be as long as the forearm follows: Grasp the head of the ham- mer as shown in sketch. Let the handle rest on the forearm, and the elbow should be at the end of the handle of proper length. A Strong Cement for Leather A liquid cement for leather, one which will not be affected by the action of water, is gutta percha, dissolved in carbon disulphide until it is of the thick- ness of treacle or molasses. The parts to be cemented should be shaved thin. Pour a small quantity of the cement on both ends, spread it well to fill the pores of the leather, warm the parts over a fire for about a half minute, apply them quickly together and hammer well. The bottle containing the cement should be tightly corked and kept in a cool place, and will keep if cared for.

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842 A Home-Made Filter for Outdoor Use A good filter that will find favor with campers who desire pure water from streams has been devised by a French physician. As shown in the accompanying picture, an ordinary tin box is soldered to the bot- tom of a metal water-pail. The floor of the box is perforated with rows of holes which extend ” through the pail i, bottom. A coiled * spring attaches m~- the cover of the Z. box to the bottom and is made to pass through a tin tube in thé center of the box. Al- ternate layers of powdered char- coal and well-packed cotton are now placed in the box; and the pail is sus- pended in a stream. Gradually, as a result of air pressure, the pail will fill up with filtered water. Then, by loosening the chain, the spring cover drops back on the box, and the pail, full of water, may be lifted out of the stream. The water may be further sterilized by adding a few crystals of potassium per- manganate. A very few crystals, not enough to tint the water, should be used. Potassium permanganate is one of the cheapest and most powerful of disin- fectants. To Keep an Auto Jack Level Very often, on account of the uneven nature of the ground, it becomes neces- sary to use some means to keep a jack level when lifting an automobile axle. aN The device in the \ illustration pre- sents a simple solu- tion. A block of 47 wood, 8” square and 2” thick, is grooved by means of a band-saw so as to cut out a semi- circular strip. This is adjustable to any position in the groove ; and it may be used to provide a level surface for a jack when the road is uneven. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE An Improved Liquid Atomizer The ordinary atomizer used for sup- plying liquid fuel to boilers has the dis- advantage of spreading the oil in all di- rections, with a consequent waste of some of the fuel. The device illustrated, how- ever, causes the oil to be sprayed in one plane only, namely, at right angles to the nozzle. The liquid, — under heavy pres- \\ sure and unmixed with air, enters the tip of the nozzle through a small ring-shaped chan- nel. A very rapid whirling motion is imparted to the oil within the nozzle, and as it emerges from the slot sepa- rates into two fine- ly-divided sprays,” one moving off ina right-hand, and the other flowing in a left-hand direction. A Rivetless Hoop As shown in the accompanying illus- tration rivets are not needed when mak- ing hoops for pails or barrels. The ends of a strip of sheet metal are bent at right angles, so as to resemble the letter Z. The strip is then bent in such a way that the two bent-up ends rest against each other in an inter- locking joint. An- other strip of metal, about three (°° times the width of * the hoop, is then bent into three equal sections and fitted over the.joint in the hoop. Improved Shellac Varnish Add a teaspoonful of Venice turpen- tine to a half pint of shellac varnish and it becomes elastic and glossy, and sticks well to polished metal exposed to the weather, and mixes well with dry colors, such as lampblack for a glossy black, and verimilion for red.

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An Electric Wax Pencil In winding coils and armatures, the amateur electrician often finds it neces- sary, when interrupted in his work, to seal the ends of his wires to prevent their unwinding. The device in the illustra- tion shows a wax pencil which uses an

hush button —<—Hlt An electric wax pencil is valuable for sealing wires temporarily

electric current to supply melted wax for just such an occasion and in as varied a quantity as may be desired. The inside parts of an old clutch-pencil of the nick- eled or German silver variety are all re- moved, leaving a metal shell with a clear passage from end to end. Cover this shell with a layer of ordinary tape. Upon this tape, beginning at the pointed end, wind a layer of No. 26 bare German silver resistance wire, spacing each turn 1/16” from its neighbor. Leave enough wire at the ends to furnish connections to the switch and battery. Wind a sec- ond layer of tape over the bare wire; and slip a snug-fitting glass, rubber or metal tube over the pencil to provide a cool grip. Now fill the inside of the pen- cil with melted wax, which, when hard- ened, is ready for use. A battery of four cells, connected to this pencil, will cause the wax to melt and flow from the nar- row end of the pencil in less than half a minute. The pencil furnishes an excellent means for sealing wires and for other work where little wax is required.

POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 843 To Make Copper Oxide for Batteries An excellent way to make copper ox- ide for use in batteries is as follows: Take a quantity of copper filings or fine copper shavings and heat them in a cast iron container or in a crucible till they are red hot. Stir them with an iron rod and while still stirring sprinkle a little water over the filings until they become ocher red. You will then have a good quality of copper oxide. Copper oxide plates may be made as follows: Mix the granulated or coarse copper oxide with 5% or 10% of mag- nesium chloride and heat the heavy mass in forms, made of iron sheeting, the forms being of the size of the wanted plate. The more chloride of magnesium used, the more porous the plates will be. The coarser the copper oxide, the better will be the results of the process and in the battery itself.

For the Lacquer Man The device in the illustration is designed to hold small articles that are to be lac- quered or dipped, and to prevent soiling and finger marks on the work. A piece of No. 10 steel wire about 18” long is bent around a piece of pipe so as to form a spring at its center. The ends are sharpened and slightly bent out, and may be used to hold objects when lac- quering,

To Make Sharp Corners in Sheet Metal: An old file can be used to make the tool required .. to enable the ama- . teur mechanic to bend sheet metal at sharp corners. Anneal the handle-end first, and then bend it at right angles, as shown in the sketch. File the point to a right-angled, V-shaped edge. The sheet

metal may now be scratched at the de- sired point with a scratch awl; and with the aid of a point of the file, the scratch can be dragged out and deepened, until the metal can be bent up at a sharp angle.

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844. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE An Automatic Telephone Lamp The accompanying drawing shows how the ordinary telephone hook may be used to light a small electric lamp con- veniently situated so as to aid the user in looking up numbers or taking down information. Fasten a piece of spring brass to a block of fiber and then screw this to the telephone cabi- net in such a posi- tion that the cir- cuit, including the battery and the lamp, will be closed at the gap when the receiver is removed from the hook and will thereby light the lamp. The strip of spring brass should be insulated from the telephone by gluing to the brass a piece of hard rubber or fiber.

A Home-Made Hand Klaxer HE accompany- ing drawing shows how a hand klaxer can be con- structed from very inexpensive materi- als. The horn is made of sheet tin, and is attached to the wooden head. A steel or a brass rod, fitted with a suit- able handle, passes through the wooden head, where it is held against the washer by means of a spring. The inner end of the rod is toothed so as to enable it to operate the gear. When the rod is pushed into the horn the gear causes the brass or wooden strip which is attached to the horn to vi- brate and to emit the usual klaxer sound. The spring forces the rod out when the pressure on the handle is removed, en- abling the operator to maintain a con- stant production of sound.

A Film-Developing Hint LIPS for hold- ing strips of photographic film d ) | when developing, fixing and drying 4 zz can be made from a brass strip as long as the film is wide, with a spring paper clip soldered — at each end.

oo —_.

Removing Solids from Filter Paper With the aid of the apparatus shown in the illustration, sediments and precipi- tates which accumulate on filter papers may be readily re- moved. The large flask is fitted with a rubber stopper con- taining two holes, The longer tube, bent as illustrated, passes through the =" stopper almost to the bottom of the flask; and a shorter tube also is inserted. A small glass nozzle is attached to the outer end of the larger tube, and by blowing through the short tube a stream of water from the flask is projected against the filter paper, from which sediment is thus washed.

)

x ILS

t <A “ENS

Simple Polarity Indicator To show the polarity of an electric terminal, an easily made indicator con- sists of a small bot- tle containing a strong solution of common salt, and two copper strips immersed in this solution. The strips pass through a cork which is paraffined to prevent leakage. If this device is connected in a cir- cuit, the strip at which bubbles form is known to be the negative pole of the circuit. Amie Alli, |

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RADIO SECTION Devoted to the Encouragement of Amateurs and Experimenters in the Field of Radio Communication TO OUR RADIO READERS The Radio Section in this issue, which is the second under the new editorial policy of the Poputar ScrteNcE MontuLy, should be of still greater interest and value than that of last month. The leading article, on “Recent Radio Inventions,” by Mr. A. F.. Jackson, analyzes the novel features of several devices and methods patented during the last few months, and clearly describes them. Mr. A. J. Watt’s resumé of sustained wave generators and receivers in commercial use is concluded, and a number of useful construction notes are given. A series of articles discussing the elementary problems of wireless transmission for both amateurs and professionals begins with this issue. Our new department of Book Reviews is opened this month; in these reviews it is our intention to indicate the scope and usefulness of each publication, from the radio viewpoint, more fully than has been done elsewhere. The Radio Club News department also begins in this number, with an article on organization and conduct of such societies. The Editor will be glad to receive and publish news of the various radio associations throughout the country. “What Radio Readers Want to Know” has proved so helpful that it will be continued as a department; the queries will be answered as accurately and concisely as possible. As to the future: It is our intention to continue from month to month the departments on Recent Radio Inventions, Construction Notes, Book Reviews, Radio Club News and Queries. In addition to these, special articles on the applications of radio telegraphy and telephony will appear each month. The Editor will welcome com- ments from our readers as to the most interesting and useful portions of the Radio Section, as well as suggestions for new departments, and new material for publication. 845

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Recent Radio Inventions By A. F. Jackson ETHODS of and apparatus for gener- ating sustained waves in radio teleg- raphy and radio telephony are arous- ing more and more interest as continuous waves become more widely used. The best known generators are the directly operating of Fessenden, radio frequency alternator, the Goldschmidt reflec- (II tion alternator, the Joly-Arco. frequency transformers and the Poulsen arc. Marconi’s proposal to secure radio frequency sus- tained alternating cur- rent by the successive discharge of condensers sers c’, c’, c*, and the primaries 7", ?, is reached The secondary circuit 0, s*, s*, having a series condenser and additional primary coil, jg tuned to synchronism with the impulses jn the sub-circuits. Thus sustained radio fre. quency currents are set up in this intermediate circuit, and these, acting inductively on the aerial circuit at f, continuous waves, Obviously the same arrangement can be used to generate elec. tromagnetic waves in groups of high or low group frequency in- stead of undamped has, however, recently radiation. been disclosed by the issue of U. S. patent 1,136,447 of 1915. It is stated that the appa- ratus there described is of the character used in the sustained-wave ve tests between Clifden and Glace Bay. The patent specifica- ‘SS II It has long been known that in radio telephony, for ex- ample, speech can be transmitted by the use of waves of very produce the desired Y - Z high group fre quency, SiH Lee deForest shows, in United States patent 1,125,496, of tion illustrates two forms of the new send- er, the simpler of which is shown in Fig. 1. In this diagram it is seen that when the key b is depressed the source of direct current a, acting through impedance i, applies a voltage across the serially con- nected condensers k. k. The outer termin- als of these condensers are connected to the studded insulated discs d, d', whose contacts are so spaced that the three subordinate con- densers c’, c*, c® are connected between the central point of k, k* and, alternately and successively, the positive and negative feed wires from a. This arrangement results in charging the three sub-condensers successively in one direction through one of the primary inductances (say 7), then successively dis- charging them and re- charging in the opposite | sense through 7, and Fig. 1—Marconi method of securing undamped wave 1915, a simple method of: producing such waves and of using them for wireless telephony. In the diagram Fig. 2, B represents an alternating current dynamo of about 3,000 cycles per second, which is connected through transformer F to the quenching spark gap D, the closed circuit con- denser C and the primary portion of the direct connected oscillation transformer G. The sec- ondary portion of this coil is led to the an- tenna A and to earth E through microphone M. As used in a practice a condenser is often inserted in the primary side of transformer F, for tuning circuit to alternator frequency. In operation the quenching gap is adjusted to produce a uniform discharge of such high group frequency that the individual impulses scarcely affect the telephone at the re- ceiving station. Talk- repeating. By adjust- ing the speed of the rotating discs and choosing the proper number of condensers, F ing into the micro- phone then produces -* 8 amplitude changes in = the radiated waves, ie a and speech is trans- a synchronous relation with the resonant per- iod of the circuits through the condensers k, k? the sub-conden- for Fig. 2—De Forest’s system > very high group frequency 846 mitted in the usual way. The novelty of the method seems to lie in the use of the producing waves of quenching gap at suf-

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y 1 f e ficiently high frequencies for radio telephony. Wireless telephone transmitters which rely upon carbon microphones to modulate direct- fy the radio frequency current are, of course, limited in output by the power which can be passed through the microphone without undue heating. A device intended to remove this power restriction: is the subject of United States patent 1,148,827, issued in 1915 to Wal- ther Burstyn. In this disclosure an electro- static modulating de- vice, such as shown in Fig. 3, is suggested. Between a series of rigid plates are sup- ported a number of mechanically linked diaphragms a. Al- ternate fixed plates (marked c and d) are connected to terminals k*® and k’, while the diaphragms a are connected to terminal k*. The in- strument thus built is placed in circuit at V according to Fig. 4, where e represents a battery, m a micro- phone, ¢ a telephone transformer, y an additional polarizing battery, and f an antenna excited by radio frequency generator g through inductive coupler e, ¢. The operation of this multiple-cell condenser transmitter is quite simple. When the microphone speech-currents act through -erminals k*, k® they cause the diaphragms a to move to and from plates d in accordance with the voice waves. The movements of the diaphragms correspondingly and _ simultane- ously alter the capacity of the condenser formed across k', k® by plates c and a. This varying condenser, being connected directly in series with the antenna, throws the aerial system more or less closely in tune with the exciting alternator g. The changes in reson- Burstyn static Fig. 4—Burstyn method of increasing the output of the microphone in wireless tele- phony POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ‘847 ant condition thus produced by the voice control the current in the aerial circuit and therefore that in the receiving telephone. So, assuming an amplifying operation by the mul- tiple static transmitter V, it becomes possible to telephone by radio over longer distances than could be covered if the microphone were directly in series with the antenna. A problem quite different from any of these occasioned the invention disclosed in United States patent 1,141,- 387, granted to Charles S. Franklin in 1915. For many radio stations it is ad- vantigeous to limit reception or transmis- sion to a given direc- tion, instead of com- municating with equal freedom in all direc- tions. One way of re- stricting the electro- magnetic waves so that their greatest in- tensity lies in a single vertical plane is to use a magnetic loop an- tenna. This loop may modulator be one or_ several P k! k 2 turns of wire wound about a supporting framework and _ vertically mounted. ’ Such an aerial is closely directive for Fig. 3 either sending or receiving, but it is not efficient as an antenna. The best ar- arrangement is a single turn enclosing as large an area as possible and having a small variable condenser in series for tuning; with even this, however, it is impracticable to in- crease the length of the antenna wire enough to make it a really efficient absorber or radiator. Figure 5 shows Franklin’s arrangement for increasing the size of the vertical magnetic loop antenna and still keeping it tuned to the wavelength used. At equal distances around the loop there are inserted series condensers c, of such capacity as exactly to neutralize %y % Zz Fig. 5—Franklin’s arrangement for increas- ing the size of the vertical magnetic loop antenna

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848 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE the inductive reactance of the aerial wire a adjacent to it, so making the entire aerial system resonant to the wavelength employed. The condensers are to be placed in waterproof cases d along the wires, and to be shunted by leak-coils of high impedance f to prevent slow static charges from collecting. This new an- tenna system is stated to be not only quite sharply directive in either sending or receiv- ing, but also a very powerful radiator or ab- sorber of electromagnetic waves. + Hyg Fig. 6—Fessenden tape sealer United States patent of 1915, No. 1,132,568, issued to R. A. Fessenden for “Electric Sig- naling,” contains some interesting suggestions for high speed automatic radio transmission and reception. Telegraph signals sent out at say 100 words per minute by a sustained wave generator controlled by an automatic punched- tape transmitter are received by a “hetero- dyne” or beats receiver. The signal-note pitch is adjusted to say 5,000 per second, and the received messages recorded at this high, shrill note upon a wax cylinder or a telegraphone wire. The phonographic record thus made is then reproduced at about 1/5 the recording speed, or 20 words per minute. At the re- duced speed the signal-note frequency is also reduced 1/5, of course, or to 1,000 per second. The most interesting point is that “strays,” or atmospheric disturbances, are recorded origi- nally at their characteristic frequency of 4 fi Fig.7 29 Fig. 7—Fessenden receiver using recording phonograph or 5 per second; when the record is repro- duced slowly the effect of the strays is re. duced, and the pure signal tone of 1,000 groups per second may easily be read by the trans- cribing operator. A type of sender Proposed by Fessenden is shown in Fig. 6, where the tapé sender is seen to control radiation from the compressed air gap 13 which is supplied by power from generator 16 and excites the aerial zz through the oscillation circuit 14, rs, The receiver may be as indicated by Fig. 7 in which the received-wave currents in coll 26 interact magnetically with the locally gen- erated current from alternator 29 so as to produce a heterodyne tone from the diaphragm 27. The recording phonograph and attach- ments are represented by 30, 40, 41 and 4a, Aerial for Two-Inch Coil An aerial 160 feet long, 60 feet high and consisting of but a single wire would be well proportioned for use with a two-inch spark coil if there were no radio laws, but.it will be necessary to cut it down to 100 feet if the operator were to come within the 200 meter law. The wave length of this aerial would be about 250 meters. With a two-inch spark coil, a rotary spark gap would be preferable. Radio Equipment for the University of Washington Plans are well under way for the installation of a complete radio engineering laboratory at the University of Washington, Seattle, in the near future. An antenna 800 feet in length has _ been built, extending from a water tower, 230 feet in height, to the Engineering building on the Campus. Receiving apparatus of the latest type, including audion equipment fitted with Armstrong circuits, for the reception of both damped and continuous waves, has been in- stalled, and more is being added. During the present year transmitting appara- tus will be built by students and will be counted as thesis work. This apparatus will be in con- formity with the highest standards in radio engineering and will include both the spark and arc excitation type of transmitters. Professor Magnusson, head of the Depart- ment of Electrical Engineering, is supervising the work, and will be assisted by Messrs. E. C. Miller and F. M. Ryan, students attending the university. Transmitting Condenser About fifteen 5” x 7”. plates would be re- quired for a glass condenser to use with a % kilowatt transformer, but the actual number of plates used would vary with the particular conditions.

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The Wavelengths of Antennas By John Vincent This is the first of a series of elementary educational articles on wireless subjects, which will be a feature of the Radio Section of the Poputar ScieENcE MontHLy during the coming months. While designed primarily for beginners, the subjects will be handled so exhaustively that the series will be of interest to advanced amateurs and professionals as well.—Epttor. ANY amateurs and professional opera- M tors are at a loss when they need to find the length of antenna necessary or most desirable to use for sending or re- ceiving a given wavelength, or when they wish to calculate the natural wavelength of some specific antenna. The rules for such computations are very simple, so that once they are understood there should be little or no difficulty in solving either of these problems. If a single wire is hung vertically from a mast and connected to one side of a spark gap, the other side of the gap being grounded as in Marconi’s early arrangement, the plain aerial system so formed will radiate waves of approximately 414 times its length. That is to say, if the gap is grounded directly and the aerial wire running from the the span, the total antenna length will be 80’ plus 150’, or 230’. This is equal to 70 meters (dividing by 3.28) and gives a fundamental wavelength for operation without series in- ductance of 330 meters (multiplying by 4.7). When the lead wires are connected to the center of the flat top antenna, thus making a “T” aerial instead of an “inverted L,” the length is measured from the instruments, via the lead, to either end of the span. For the flat top just described, if the leads were taken from the center instead of from one end, the total length would be 80’ plus 75’, or 155’, or (dividing by 3.28) 47 meters. The funda- mental wavelength, or that which would be radiated if the antenna were excited with- out inductance in series, would therefore be 220 meters. The fundamental spark gap to the top wavelength of an an- tenna is affected al- eS of the pole is 100° F long, the wave radi- ated will be about 457 long. To get & this wavelength in meters the number of feet must be divided by 3.28; 450’ thus is found to be 137 meters. This, then, is the fundamental wavelength of a ver- tical wire 100” in length. To increase the wavelength which is to be sent out, it is neces- sary to add inductance in series with the aerial, or to increase its own length. How- ever, when wire is added in coil form the wavelength is increased by much more than 4.5 times the length of the wire in the helix. If ‘the antenna wire runs for part of its length in an approximately horizontal posi- tion, and if the aerial consists of several wires in parallel, as is common in radio sta- tions to-day, the length of the fundamental wave will be about 4.7 times the length of the aerial itself, because of the added capa- city due to nearness to earth. Thus, if the spark gap, having one side grounded, has its other terminal connected to an aerial con- sisting of six parallel wires 150’ long strung between the tops of two poles 60’ high, with a lead-in wire 80’ in length from one end of a em MTEL Total length, 155 feet; natural wavelength, 220 meters most entirely by its length, and very little by the number of wires used in parallel. Whether you use two wires 6’ apart and 200’ long, or 8 wires 4’ apart and 200’ long, the fundamental wavelength will re- main practically the same. However, with more wires stretched side by side the effective resistance of the conductors will be less and the ratio of antenna capacity to antenna inductance increased, so long as the wires are kept quite well separated. Not much is to be gained through the reduction in re- sistance, since the wire resistance is so small a part of the total resistance of the antenna- and-earth system. For working at wavelengths considerably above the fundamental, though, it is advantageous to build the aerial with many wires, i. e, of large capacity, for it can be then tuned to the longer waves with less loading inductance. All of the above has to do with the funda- mental wavelength of aerials. The actual operating wavelength nowadays is usually much greater than the fundamental, since in- ductance coils are added in series for the purpose of coupling to the closed circuit of

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850 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE the transmitting station. The “plain aerial” arrangement, which sends out waves of the fundamental length, is not used at present on account of the high damping of its waves and the broad tuning which is thereby neces- sitated. Some few antennas are used with condensers in series, in addition to the coupl- ing coil inductance, so as to operate on wavelengths very close to or below the fun- damental, but this arrangement is not efficient. The usual plan provides for inductance in series, and the usual wavelength is therefore greater than the fundamental. In order to calculate the operating wave- length of an antenna when a given induct- ance is placed in series with it, it is neces- sary to consider antenna capacity and an- tenna inductance. Every aerial has both these properties in varying amounts, and its natural or fundamental wavelength is deter- mined by the product of its capacity and its inductance. The longer any antenna is, the more capacity and the more inductance it pos- sesses, and therefore mate rule of multiplying the antenna’s length by 4.7, which was 330 meters. The more com- plicated method of calculating from the known inductance and capacity is the more reliable way. This second rule is the one to use for finding the wavelength of operating antennas when a known amount of inductance is con- nected in series and the wavelength is there- fore increased. It is necessary only to use the total inductance of the system, which is obtained by adding together all the induc. tances connected in series, in place of the antenna inductance alone. Consider the same flat top antenna having connected in series with it an oscillation transformer secondary of 1/10 millihenry inductance, and a loading coil of 25/100 millihenry. The total induc- tance is then 0.023 (antenna) plus 0.1 (sec- ondary) plus 0.25 (load coil) or 0.373 milli- henry. The capacity is unchanged, 0.0012 microfarad. ‘The operating wavelength is found as before, by (1) multiplying the in- ductance by the the longer is its ~ 150’ PF NS natural or fundamen- capacity, with the re- LA sult 0.000476 or, tal wavelength. The more parallel wires in any antenna the greater is its capacity, but the Jess is its in- ductance. These two quantities change in opposite and equal amounts as wires are £0’ N ( M@@@@EE@ETTH@€@Clld i since three figures be- sides the zeros are al- ways enough, 0.000447, (2) taking the square root of this, with the result 0.0213, and (3) multi- plying by 60,000, with the final result of rs) added side by side, so Total length 230 feet, natural wavelength 1,270 meters, the oper- that the fundamental wavelength remains about 4.7 times the actual antenna length, as explained above, for all ordinary aerials. If we are able to find out the capacity and the inductance of any antenna we can calcu- late its natural wavelength at once. It is only necessary to multiply the number of microfarads capacity by the number of mil- lihenrys inductance, take the square root of the resulting number and then multiply by 60,- 000. The answer is the natural or fundamental wavelength in meters. As an example, let us consider the flat top inverted L aerial de- — scribed above, which has a total length of 230’ or 70 meters. The capacity of this an- tenna is fairly large, since the wires are 6’ apart, and measures 0.0012 microfarad. The inductance is 0.023 millihenry. Its funda- mental wavelength, according to the rule just given, is found by (1) multiplying these two figures together, with the result 0.0000276, (2) taking the square root of this, with the result 0.00526, and (3) multiplying by 60,000, the final result being 316 meters. This is reasonably close agreement with the natural wavelensth found by the simpler approxi- 330 meters ating wavelength. Thus it is seen that placing coils to the amount of 0.35 millihenry in series with the antenna has increased its resonant wavelength from 316 to 1,270 meters. The two ways of calculating wavelengths of aerials just explained are the only two really reliable methods for doing this. Any plan based upon the number of feet of wire coiled up in the transformer secondaries, or on anything except the quantities leading di- rectly to the true inductance and capacity of the antenna itself, is likely to give very in- accurate results. The computations are at their best uncertain when used, before it is put up, to predetermine the kind of antenna desired. When an antenna has been built, however, and when its capacity and induc- tance are known, the second rule given above is quite dependable. Nevertheless, for accu- rate results, the best way to find the operat- ing or natural wavelength of any existing antenna is to measure it with a wavemeter. Very often it is desired to find out before erection just how large an antenna will be necessary for radiation of waves at some cer- tain wavelength. This can be done quite eas- - wp ae oe leet et AF rH

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ily by working backward the rule first given. Suppose one wishes to send on a wavelength of 200 meters, the longest permitted to ama- teurs by present radio regulations. Remem- bering that it is inefficient to operate the aerial at less than 144 times it natural wavelength, the longest permissible fundamental wave- lengtli is found, by dividing 200 meters by 1.25, to be 160 meters. For this natural wave- length the antenna should be 160 meters di- vided by 4.7, or 34.5 meters in total length. Multiplying 34.5 meters by 3.28 gives 112’, which is as long as the proposed aerial should be. For 200 meter sending, then, the antenna might well consist of 4 parallel wires, each pair 4’ apart, slung between 40’ poles 70 = 150+ -- ~ Sa \ 4 >» YS IN — HPSS oun ULTN “NS AY ‘S Antenna capacity .oo microforad Antenna inductance .oe3 millihenry. | a wes Mmilihenry VUULLU Y 10777. iA Ts a. e tL Antenna system working on wavelength of 1270 meters apart, with the lead taken from one end. To get greater capacity the “T” form might be used, in which case the poles could be 140’ apart. Either of these antennas would have a natural wavelength below 160 meters, and the amount of inductance to place in series in order to reach 200 meters would be sufficient to give coupling with the closed circuit at the sender. The exact amount of inductance needed could be calculated by using the sec- ond rule backwards, if the antenna capacity and inductance were known. As a: general thing, however, it is not possible to approxi- mate these values closely enough to make the calculation of much value; it is best to wait till the antenna is finished and then to meas- ure its capacity and fundamental wavelength. Knowing these, the amount of inductance needed for any wavelength may be computed easily, as has been shown. But the wave- length of 200 meters may be reached very POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 851 easily, even without knowledge of the exact antenna capacity and inductance, for having once built the antenna of suitable natural wavelength according to the method just ex- plained, it is only necessary ta add inductance a little at a time, measuring the wavelength at each step and stopping when that desired is attained. It is always useful to remember that, re- gardless of the size or kind of wire, the num- ber of wires, or their spacing or their height from the ground, the fundamental wave- length of any ordinary antenna is very nearly 4.7 times its actual length. The antenna length must be stated in meters if the wave- length is desired in meters; or in feet if the answer should be in feet. The total length of the aerial is the only factor that largely determines its natural wavelength, Wireless Club—University of Missouri This society was organized at the beginning of the school session, 1914-1915, at the Uni- versity of Missouri, Columbia, Mo. At pres- ent the club has about 15 members. Meetings are held weekly and addresses made by mem- bers of the university faculty or papers read by members of the club. The organization maintains a wireless sta- tion at the university for the use of its mem- bers. The antennae of this set is made up of 4 wires, stranded copper, 120’ long, 90’ high at one end, and 80’ at the other. The sending set which has been installed consists of a % kw. G. E. 10,000-volt testing transformer, oscillation transformer, rotary spark gap and condenser. The receiving set consists of 2,000 ohm phones, Perikon, Galena, and Audion dectec- tors, loading coil, loose coupler and variable and fixed condensers. With the above set, Key West, Arlington, Sayville, Illinois Watch Co., Gulf boats and many other stations have been heard. During the Easter holidays returns of the Willard-Johnson fight, personal messages, or- ders, etc., were sent from this station to the cadet encampment of the Missouri State Mil- itary School, which was held at Rocheport, Mo., on the Missouri River, 15 miles from Columbia. The officers of the Wireless Club of the University of Missouri for the coming sea- son are: Robert M. Walker, president; Clar- ence O’Daniel, vice-president ; Vernon G. Cox, secretary and treasurer, and Elliot A. White, faculty advisor. All communications should be addressed to the secretary, at Benton Hall, Columbia, Mo. The club would like to hear from nearby ama- teurs. + mnt er oer SE areas earn P oan nea

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852 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE A Crystal Detector The diagram shows how a detector which cannot lose its adjustment may be made. It may even be dropped on the floor without loss of sensitivéness. The cost of making is very small, since it requires only a brass or metal cap, a piece of silicon, two battery screws and some sealing wax. First drill a small hole in the bottom of the cap, just large enough for a _ bat- tery screw to slide through. Next secure a piece of silicon hav- ing a flat surface, and bind small pieces of fine copper wire very tightly around each end of it. After doing this, bring the two ends of wire together and join them with the head of the battery screw at the bottom of the cup. Then pour hot sealing wax into the cup, bringing it even with the level of the silicon, being careful not to drop any on the crystal. Next place about eight layers of tissue paper on top of the silicon, and find a sensitive spot by punching a needle (which is to be connected to a test buzzer) through the paper. After locating the right spot, carefully remove the needle and insert a piece of copper wire in its place. Then pour in wax enough to fill the cup, and connect the wire with a battery screw at the top. This gives a fixed detector which will last some time before it loses its sensitiveness. Two which were made a month ago are working finely. Care of the Station To obtain the maximum efficiency from any wireless set one must use a little sys- tem. A few minutes’ work every day will improve both the appearance and working range of your station. The following station routine has been used for four years in one plant, and is found entirely satisfactory: DAILY. Wipe off all instruments with care. Tighten all contacts. Clean commutator of rotary gap motor. WEEKLY. Polish all metal work, key, switches, etc. Rub down and polish instrument cases. Examine all contacts from power source to antenna. Vaseline movable contacts lightly. Blow out armatures and fields of motors. Wipe off glass of condensers and clean rack. Clean and polish transmitting inductance. Oil rotary gap motor. MONTHLY. Clean and tighten ground contact. Clean key contacts and see that faces are parallel. SEMI-ANNUALLY. le Lower antenna, clean off insulators, over- haul ropes and replace old and worn ropes with new. Polish all hard rubber work with carbon bisulphide (this can be obtained from any drug store). THINGS TO BE REMEMBERED. Do not finger detector crystals, for by do- ing so you reduce their sensitiveness To clean old and dirty crystals wash with carbon bisulphide, using a toothbrush; then wash with soap and water and finish by washing in clean water. Receiving instruments should be as far from transmitting apparatus as practicable, Long lead wires between instruments should be avoided as much as possible, for they cut down efficiency. Keeping contact points bright cuts down resistance losses. Short circuit detector while transmitting. Keep the spark white and crackling. If there is an arc lengthen the gap. If the spark is stringy shorten the gap. A micrometer gap made of two strips ot brass on the aerial and ground binding posts will save your receiving outfit in time of lightning storms. A Contact for Crystals Take a 100-watt mazda lamp and break the glass bulb, being careful not to damage the glass stem inside; then lay the glass stem con- A wire-contact from an old lamp globe taining the copper lead-in wires A on a block of wood, and with very light blows, from a small hammer, break off all the glass. Be cautious not to injure the platinum wire B or the connection C. Next, cut off the plat- inum wire very close to D. This leaves, as shown in E, the copper wire with the platinum wire attached. The fine platinum wire does 4° not discolor or tarnish and gives a good light contact with a crystal when used in a well built detector stand.

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Undamped Oscillation Systems of Radio Telegraphy By A. J. Watts (Continued from November) N point of simplicity of construction neith- er of the systems just described for the production of undamped oscillations can approach that of the Poulsen arc as developed by the Federal Telegraph Company. A simple diagram of the connections of this apparatus is given in Fig. 3, wherein the arc gap C D consists of two water-cooled electrodes which burn in a chamber supplied with a steady stream of hydrogen or ordinary illuminating gas. Two blow-out magnets, E and D, are connected in series to the source of energy through the arc and ama, and at Point Lom4, San Diego, Cal. (The arc and spark apparatus are both used at Arlington.) These three stations are lo- cated about 2,500 miles apart and have car- ried on successful daylight communication. “BEAT” RECEIVERS For a number of months the amateur field has had an inkling of certain extremely long distance experiments performed by amateur and professional investigators, who, by means of a single audion detector, have taken down messages from high-power stations at dis- tances from 3,000 to are placed at right angles to the arc points, tending to make the electrodes burn evenly, and also to produce a greater difference of poten- tial between the arc terminals than would be possible without De them. Inasmuch as the arc is connected directly in series with L, a while the circuits for this apparatus have l passed from one to another in a quiet way, few have been really able to produce workable equip- ment which could be relied upon. The de- tails of the dimension c of the various coils | 6,000 miles; and the antenna system the frequency of the emitted wave is gov- erned by the induct- ance, capacity and re- 500 1500 Vols Fig, 3 TINT £ comprising such a receiving tuner have not been published, because the apparatus is not generally un- derstood. Therefore, sistance of the arc gap and the antenna system. Hence the emitted wave may be instantly changed by the mere insertion of a few turns of inductance in the antenna circuit. As a matter of fact, the commercial stations of the Federal Tele- graph Company are fitted with a number of switches for immediate change of the emitted wave in order that long distance communica- tion may be maintained during the periods that the reflection and refraction phenomenon of the upper atmosphere changes. Thus it is found that often when a sudden depression in the strength of signals takes place between two long distance stations, proper selection of another wavelength will restore communication. The only disadvan- tage of the Poulsen arc system lies in the fact that the arc electrodes require considerable attention, such as cleaning, renewing, etc. Transmitting apparatus of this type is em- ployed at the large United States Navy stations at Arlington, Va., at Darien, Isthmus of Pan- Fig. 3—Wiring of Poulsen arc sender 853 data for a tried and tested set may be of interest. In the diagram Fig. 4 we have given the circuits of a receiving tuner which will allow the reception of signals to a distance of 3,000 miles in daylight when employed in connec- tion with an audion of the proper character- istics. It may be mentioned at the start that the type of audion having a double plate and double grid is preferable for this work. Referring to the diagram, the primary wind- ing of the oscillation transformer L 2 is 814” in length by 5%4” in diameter, wound closely with No. 24 S. S. C. wire. Variation of the inductance value may be obtained by a mul- tiple point switch or sliding contact, prefer- ably the former. The aerial tuning inductance L 1 is 28” in length by 542” in diameter, wound closely with No. 20 S. S. C. wire. Taps may be brought from it at intervals of 1”. The secondary winding L 3 is 14” in length by 5” in diameter, wound closely with No. 28

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854 S. S. C. wire. It also may be fitted with a multiple point switch, taps being taken up every %”. The secondary loading coil L 4 is 22” in length by 514” in diameter and may have two or three tapoffs at the low potential end. The inductance coil of the telephone cir- cuit L 5 is 27” in length by 514” in diameter, wound closely with No. 28 S. S. C. wire. The coils of the radio frequency trans- former L 6 and L 7 are connected as shown and placed in variable inductive relation. These coils are of nearly like dimensions, viz.: L 6 is 5” in diameter by 7” in length, wound closely with No. 28 S. S. C. wire. L 7 is 5%” in diameter by 7” in length, wound with wire of the same size. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE able functioning of the apparatus follows: When a certain critical potential is applied to the local telephone circuit of the audion and the filament brought to a definite degree of incandescence, the local circuit of the aud- ion becomes a generator of undamped oscilla- tions, the frequency of which is determined by the condenser C 3, the inductance L 5, and the coupling coil L 7. Generally the entire coi] of L 5 is in use, and the adjustments for fre- quency made at C 3 alone. By a suitable value of coupling between L 6 and L 7 the oscilla- tions of radio frequency from the local circuit are amplified by the well-known trigger action of the audion. The secondary circuit and the local telephone circuit must therefore be tuned ] L, NI Lz anit Ls Phones Fig. 4—Diagram of the Armstrong circuit The variable condenser C 1 may have a max- imum value of capacity of 001 Mfds. The maximum capacity of C 2 need not exceed .0002 Mfds. C 3 should have a value of .001 Mfds. and C 4 about .003 Mfds. The filament battery B has a maximum po- tential value of 4 volts, while B 1 may have a maximum value of 60 volts. The rheostat R should be of 10 ohms resistance. OPERATION It is to be especially noted that the con- denser C 2 is generally employed at exceeding- ly low values of capacity, not over .00001 Mfds. Having connected the apparatus in accord- ance with the diagram of connections in Fig. 4, the procedure for adjustment and the prob- to resonance. It now only remains to tune the antenna system to the incoming wave and the secondary circuits to a slightly different frequency, thereby producing the well-known heterodyne or “beat” action, as first suggested by Fessenden. The tuner described is only suitable for the reception of wavelengths between 6,500 and 10,000 meters, the over-all dimensions being too great for the shorter range of wave- lengths. For receiving signals from Tuckerton using the Goldschmidt alternator, an extremely pure musical note is obtained which may be varied from about 200 cycles to the limits of audibil- ity by means of the variable elements of any of the circuits. The note obtained from the

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Poulsen arc is not so pure on account of the irregularities of the arc itself, but an equally pure tone is possible from the Joly apparatus as used at Sayville. In order to obtain satisfactory results, the adjustments of this apparatus must be ex- tremely precise throughout, more so than with any other type of receiving apparatus. On this account if efficient results are not ob- tained it is due to ignorance on the part of the manipulator concerning, the best working adjustments of the audion. A few trials, how- ever, will familiarize the operator with the circuits. The apparatus under consideration is so sensitive that the POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 855 circuit. Care should be taken not to crack the bulb. (3). The most sensitive audions are those where the “blue glow” increases slightly with small increments of potential of the high potential battery. If the “blue glow” appears suddenly and is unstable—appearing and dis- appearing—the bulb will be erratic in action. (4). When generating undamped oscilla- tions the bulb should be used below the “blue glow” point. (5). With certain audions, after the above treatment is applied, the filament need not be burned brighter than cherry red. The foregoing apparatus, employed in con- nection with an aerial operator adjusting it to resonance must stand at a distance of at least 3’ from the secondary tuning coils and variable con- densers, otherwise the associated circuits will be thrown out of resonance when the body of the adjuster inate this effect the variable condensers should therefore be fitted with long handles, say 20” in length. When the local telephone circuit and the secondary circuit are out .of reson- ance certain types of audions will produce a hissing or musical note, but when ad- SES ) Y rs a 2 ME” is removed. To elim- = having a natural period of from 400 to 1,000 meters, will permit the reception of signals from Darien, Nauen, or Hanover, Germany, in daylight. After dark signals may be received on the At- lantic coast from the Federal Telegraph Company’s station at Honolulu. The apparatus is also most sensitive to spark stations within the wavelengths for which it is designed, but at the point of greatest intensity of signals the normal note of the damped wave is destroyed, the resultant note in the receiving appar- a ¢ justed together the telephones are quiet. It is positive proof that the audion is generating undamped oscil- lations if, when the capacity of the condenser C 4 is varied, a certain peculiar “thud” is heard in the telephone receivers. HOW TO MAKE THE AUDION OSCILLATE Certain audions require preliminary treat- ment before they become efficient and sensi- tive undamped detectors. A series of experi- ments have disclosed that the following char- acteristics are essential for efficiency: (1). The audion should be one where the “blue glow” appears at a very low voltage in the telephone circuit—not over 25 volts. (2). Many audions may be brought to this state by the application of a small blow torch to the bulb while the filament is burning and with at least 60 volts applied to the telephone Fig. 5—-Thirty K.W. Poulsen-Federal arc transmitter atus being of a lower frequency. By a slight sacrifice of intensity of signals the normal note may be maintained with considerable amplification. In the latter case the reception of signals is not based on a true heterodyne or “beat” action. With prop- er adjustment of all circuits indicated in Fig. 4, amplifications of 1,000 to 2,000 times the strength of signals obtainable with the ordi- nary circuit will be produced. RADIO CLUB AT ANN ARBOR A radio club has been formed in Ann Ar- bor, Mich. The officers are Mr. Glover, Pres. ; Mr. Bucholz, Vice-pres.; Mr. Overbeck, Treas.; and Mr. Hoffan, Sec. The club has the sup- port of the Y. M. C. A. and access to its educational features of wireless, and is lo- cated at the University of Michigan,

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Policing. the Air A great many radio clubs are organized each year, but more than 80% of them are disband- ed before the first officers have served their full terms, owing to lack of interest. There is a most successful radio club in one of our large cities, and one of the most novel and creditable ideas ever introduced in radio club circles is in full swing there at the present time. The members call it “Policing the Air.” Every night there is an operator on duty at his private station, with a log sheet in front of him and a call list within reach, Should any amateur persistently interfere after having been requested to keep out, send false distress signals or violate any rule made by the committee on rules and regulations, or violate any law enacted by the United States Government, his offense is noted in the police- man’s log book, which is turned over to the committee on rules and regulations at the next regular meeting of the club. The offender is then compelled to pay a cash fine or be sus- pended from club meetings, or both; and should his offenses become too numerous he is expelled. A different policeman is on duty each night in the week. HOW TO ORGANIZE A RADIO CLUB To organize a club three or four men should get together and fix upon time and place for a meeting. Then they should notify all nearby amateur and commercial operators, and those others interested in wireless teleg- raphy. A wireless set may sometimes be used to good advantage for announcing the meet- ing. A general message with all necessary in- formation may be sent each of several con- secutive nights. When the time set for the meeting has arrived an hour should be al- lowed, if possible, for conversation, and to allow all interested to assemble. A temporary president should be appointed, and also a temporary recording secretary to note the proceedings. A president, vice-presi- dent, secretary, treasurer, chief operator and three radio policemen should then be nomi- nated and voted for, and the meeting should be turned over to them. Committees should then be appointed by the president to draw up a constitution and rules and regulations, and to fix penalties. This committee is expected to take the timeebetween the first and second meeting for this purpose. The duties of the usual officers are too well known to require detailed explanation, but those of “chief operator” and “radio police- man” may be as follows: It is the duty of the chief operator to direct the use of all apparatus owned or controlled by the club. He shall assign certain days and Radio Club News 856 hours of the week on which the different radio policemen shall maintain a steady, close watch on all amateur radio traffic. It is the duty of the radio policemen to see that the rules and regulations of the rules committee and the laws of the United States concerning radio communication be observed. All offenses should be noted in the log sheets, which are to be turned over to the chief operator for presentation to the chairman of the committee on rules and regulations at each meeting for their approval and action. It is recommended that a meeting be held once a week, and that the dues be sufficient to’ cover the rent of a hall or room. For a “nominal sum a room may be rented by the month in some small office building, where the management will permit the club to erect an aerial and install a radio outfit. If the treasury is sufficiently large, keep the leading electrical and radio magazines on file. Another way to keep interest at a high pitch is for the most experienced operators in the club to give inexperienced members from half an hour to an hour of instruction in wireless telegraphy before or after meeting hours. Ad- ditional information is found in the “Radio Communication Laws of the United States and the International Radio-telegraphic Conven- tion,” which may be obtained for 15 cents, and in the “Radio Service Bulletin,” the annual subscription price of which is 25 cents. Both may be secured from the Superintendent of Documents, Government Printing Office, Washington, D. C. Marconi Amateur Radio Association The Amateur Marconi Radio Association started its season on September 4, at Troy, N. Y., after a vacation period of about two months. At the last meeting the following officers were elected for the ensuing year: Wendell W. King, president; W. LeMay, vice- president; Harold G. Connor, secretary; J. Vaughn, treasurer. Twenty-one members now constitute the club. The Topeka Radio Club The Topeka Radio Club was organized a year ago with a limited membership of twelve. The purpose of the club is to promote and regulate radio activities in and around To- peka, Kan. Six of the members have secured government radio licenses and the entire club will be composed of licensed members in a short time. The following are the officers: President, E. Broberg; vice-president, J. Keating; secretary and treasurer, W. Beasley; sergeant-at-arms, R. Morehouse. All com- munications should be addressed to the secre- tary, Wm. A. Beasley. varia and e: of a be ov’ in the procu wood cord shoul about havir of v prev large Next 1 y," the | the the can asse cost way turr be ite ber wit La en bo pl. th an Ca

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A Cheap Variable Condenser A large number of amateurs are without variable condensers because of the _trouble and expense of building one, or the high cost of a purchased one. These difficulties may be overcome by rigging up a tin-can condenser in the form of a locse coupler. To make a variable condenser of this type procure two tin cans, a suitable base, a wooden rod, an insulated knob, 6” of flexible cord and two binding posts. One of the cans ps : —— A condenser made from tin cans should be about 1” larger in diameter, and about 2” longer than the other. In the can having the largest diameter place about 14” of waxed paper or cardboard. This is to prevent the smaller can from touching the larger one when it is pushed all the way in, Next get a wooden rod 34” in diameter and 1%” longer than the sum of the lengths of the cans, also a small pillar. Bore holes in the exact center of the bottom and cover of the smaller can large enough to permit the can to slide freely. Make connections and assemble the condenser on its base. A neater-looking condenser, but one which costs a little more, can be made in the same way by using lengths of brass tubing with turned wooden plugs at the ends. Lamp Receptacle Resistance Unit The resistance unit shown is designed to be used in place of a lamp resistance. Thus if a storage battery is to be charged a num- ber of these resistances can take the place of the bank of lamps. The unit is made from a burned-out fuse with a tube of porcelain or soapstone fast- 44 24 brass holt Solder mire to burnt out fuse Lamp resistance made from a burned-out fuse ened by means of a 10/24 threaded brass bolt with two nuts, one to hold the tube in place, and the other for the connection for the wire. The other end of the wire is soldered to the end of the threaded sleeve, and should be insulated from the knurled brass cap serving as a grip to screw the unit in. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 857 A number of these units will be conveni- ent for the laboratory, and may be wound to resistances of 5, 10, 15, 20 and 25 ohms., etc. Any required resistance may thus be obtained, An Aerial Hint To experimenters using long single wire aerials the following may be of assistance: One often needs to know whether his aerial wire has stretched or in any way been low- ered, for instance, by a passing storm, yet he does not wish to go to the lowest point to investigate. If the near end of the aerial is plucked, and the time is counted in sec- onds till the vibration returns, it may be com- pared with a similar reading previously taken at a time when the wire was fully stretched. As the time taken for the pulse to travel to the far end and return varies with the ten- sion, the height of the aerial may be readily ascertained. Terminal Connections for Condensers Many amateurs are greatly troubled by the difficult and dirty method of soldering the foil-sheets of condensers together. A sim- ple scheme shown in the drawing will be A clean way of soldering the foil-sheets of condensers of use to them. Secure a binding post and two pieces of brass about %4” wide, %” thick and 114” long. Bore a hole in the center of both pieces of brass to fit the binding post and screw the binding post up tight. How to Improve the Sound of a Buzzer It may happen that wireless operators are troubled by the harsh and hoarse tone of the buzzer test. The difficulty may be quick- ly and cheaply remedied as follows: Take a piece of match-stick about 3%” long and pry between the little piece of metal that is fastened onto the vibrator proper and on the vibrator. It will be found that the tone of the buzzer is very noticeably in- creased, Plans for Radio Club in Boston Amateurs in or near Boston who are in- terested in forming a wireless association with headquarters and central station, may in- quire for particulars at The Young Men’s Christian Union, 48 Boylston street, Boston,

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INDUCTION FROM POWER LINE E. C. S., Deer Lodge, Mont., asks: Q. 1. There is a 125,000-volt power line running 600’ from my wireless station. In my receivers I hear a high-pitched singing noise which I cannot tune out. I use a loose coupler and my aerial is at right angles to the power line. Is there anything I can do to shut out this noise? A. 1. You are so near the power line and the voltage is so high that we do not believe that it would be possible for you to tune out the interference. Q. 2. Would an interference preventer or a balanced tuner help? A. 2. Yes, but you are so near the line that you will probably find great difficulty in tuning out the interference with any kind of tuner. Q. 3. What is the right length of a 4-wire aerial 40’ high to be used with a 5” spark coil? A. 3. You will be limited by statute to 200 meters wavelength, which requires that the aerial and lead-in shall not exceed 85’ in total length, for good efficiency. AERIAL PROBLEMS J. T. B., Pauls Valley, Okla., asks: Q. 1. Is it better to use an umbrella aerial than a single wire 300’ long, 20’ high at one end and 60’ at the other? - A. 1. If the umbrella aerial is at least 60’ high it will probably give the better satisfac- tion. It will be less directional than the single wire. ‘Q. 2. Will a long lead-in wire have any effect on the wavelength of a set? A. 2. Yes; the wavelength will be increased by approximately 414 times the length of the lead-in. WAVELENGTH QUERIES C. V. H., Kinsley, Kans., asks: Q. 1. With a 1,500-meter loose coupler, a Blitzen, duplex 2,500-meter loading coil, audion detector, 2,000 ohm head phones, 0.001 M.F. variable condenser and a 0.0165 M.F. fixed condenser, can I receive any wavelength in the United States? My aerial is one wire 600’ long, 75’ high at one end and 60’ at the other? A. 1. No; but you can receive nearly any wavelength that you would probably desire to. Q. 2. Can I receive damped and undamped waves with an audion detector? A. 2. An audion can be made to oscillate and then act as a receptor for undamped waves. More variable condensers are re- quired in the receptor for undamped waves. What Radio Redon Want to Know 858 Unless you are familiar with radio work we do not believe you will have much succes, trying to use the audion in the oscillating i state. Q. 3. Would I get better results by using two wires in my aerial instead of the Single wire? A. 3. Yes, provided the wires were placed at least 8’ apart. ASSIGNMENTS OF CALL LETTERS S. H., Chicago, IIl., asks: Q. 1. Please give me full information re. garding the obtaining of a call letter for g receiving station. A. 1. A receiving station does not require any license and accordingly would not haye any call letter assigned to it. If you havea transmitting station you would be required to have an amateur station license. To ob- tain this license and the assignment of a call letter you are required to fill out two sets of blanks. The blanks for your application may be obtained by addressing United State Radio Inspector, Chicago, IIl. BUZZ IN PHONES R. H., Keyport, N. J., asks: Q. 1. Several days ago I purchased a te ceiving set consisting of a tuning coil, fixed | condenser, detector, and 1,000 ohm receivers, When I connected up the set I received a high buzz which sounds not unlike a spark, and | which I cannot tune out. It remains in con- stantly morning and night, and I can pick it up with my receivers directly connected to | aerial and ground. It is not the set, for I have tried it elsewhere with good results, | Could it be a leak from the electric light cir cuits? : A. The buzz comes, undoubtedly, from — some electric circuit. We do not know of anything you can do to get rid of it. The waves emitted are of such a highly damped character that they cannot be tuned out like an ordinary radio message. CONDENSERS AND THEIR CAPACITY A. R. H., Rapid City, So. Dak., asks: Q. 1. What capacity condensers should be | used in connection with a Packard 2 k. w. transformer and an aerial 200’ long and 7 high? ; A. 1. The amount of condenser which you could ‘use would depend on the wavelength used. To get the full output from the trans former you would probably be able to use 4 condenser of about 0.08 M. F.

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ao + —_— + He 2 ao _- 4 oOo oreo He & _ 2. How large an oscillation transformer ould be required? na 2. Wind the coils on a frame about 10” in diameter and put 5 turns on the primary and 15 on the secondary. RADIO FREQUENCY CHANGERS W. H. H., Cold Spring, N. J., asks: Q. 1. Will you kindly give me a more com- plete description of the transformer which doubles the frequency of the current imposed on the primary winding, which you mention in the article entitled “Long Distance Wireless Telegraphy” in the August issue of the Wortp’s ADVANCE? A. 1. It would be far too long an article to give in this column, but you will find one of the most complete short descriptions of radio frequency changers in print in the March, 1915, Volume 3, No. 1 issue of the Proceedings of The Institute of Radio Engi- neers. This is a 35-page article and covers not only static but dynamic, electrostatic as well as electromagnetic, frequency changers. It is fully illustrated and contains many graphs showing the relations of the several currents during the frequency changes. If you are at all interested in the subject, we most certainly recommend that you read this article. If you cannot obtain a copy of this publication from a library or member of the Institute you can purchase a copy for $1 di- rect from the Institute Secretary, 111 Broad- way, New York. Q. 2. To what degree is the core of the transformer saturated by the direct current? A. 2. The core is saturated to the point known as the knee of the curve. It is the point where the saturation begins to increase very slowly with increase of magnetizing cur- rent, FOR POULSEN MESSAGES C. N. W., Bradford, Pa., asks: Q. 1. Where can I obtain data for the construction of a ticker detector to receive messages from the Poulsen stations? A. 1. A description of the ticker detector, together with construction details, will be found on page 353 of the December, 1913, Electrician & Mechanic. The oscillating aud- ion is now being used to receive messages from stations using an undamped wave. Q. 2. Is it considered the best practise to have the windings of receiving transformers and oscillation transformers go in the same direction ? A. 2. It makes little difference. Q. 3. Should the winding of a pancake transformer commence with the outside or inside? A. 3. It makes no difference. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 859 Q. 4. Employing a 3-step amplifier and other correctly designed receiving apparatus will an aerial of the inverted L type, 2,000’ long, average height 80’, 4 wires, 6’ spacing between wires, permit the reception of sig- nals from the high power European stations? A. 4. Yes. Q. 5. Will city water pipes and gas pipes used in combination make a satisfactory ground for receiving? 4 A. 5. Yes. CONDENSER CAPACITY S. W. H., Williamsport, Pa., asks: Q. 1. Please give me the capacity of the following condenser: Tinfoil, 8 sheets 6”x1”; dielectric, 9 sheets waxed paper 6”x114"? A. 1. 0.003 M. F., approximately. AMPLIFYING SIGNALS H. M. R., Jasper, Mo., asks: Q. 1. Why is it that when I put a grapho- phone horn on the receiver to my radio set I do not get a loud sound, the same as from a graphophone? A. 2. The signals are not loud enough to be heard in the horn. In a graphophone the horn is not the whole story. The important piece is the sounding box. If you place the needle that bears on the record against the receiver diaphragm you will probably be able to get a sound in the horn. The incoming signals, however, must be strong enough to move the diaphragm under the pressure from the needle. Also you can use only a grapho- phone whose action depends on up and down movements of the needle. Many, the Victor, for example, use a lateral motion of the needle, which, of course, bars that type from radio work. In general graphophones have not been very successfully used in radio work for in- creasing the strength of signals. LOOSE COUPLER W. M. K., Windsor, Ont., asks: Q. 1. Please give me the dimensions of a loose coupler which will receive wavelengths of 1,500 meters. A. 1. The coils should be made up of 150 turns of No. 28 B. & S. gauge copper wire, wound on cylinders 5” long. The primary should be on a 514” in diameter cylinder and the secondary on a 434” in diameter cylinder. About 225 feet of wire will be required for each coil. Q. 2. What are the dimensions of a double slide tuner to receive wavelengths up to 1,500 meters, A. 2. Use the primary coil mentioned in question 1. Q. 3. Could I also use the coil mentioned in question 2 as a single slide tuner and still receive wavelengths up to 1,500 meters? A. 3. Yes. np iC

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860 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE SPARK GAPS H. E. G., Rockland, Mass., asks: Q. 1. Will a quenched gap work in series with a rotary gap? A. 1. Quenched gaps have been used with good results in series with rotary gaps. A rotary gap is usually a quenched gap in itself. Q. 2. Does this combination increase the pitch of the spark? A. 2. Such a combination would have very little effect on the tone of the spark. Increase the speed of the rotary gap to increase the pitch of the spark. Q. 3. How many discs will I have to use on a 13,200-volt transformer spark? A. 3. This will depend on the rotary gap. The combination of the two gaps is very much an experimental one, and about all we can tell you is to make a gap with 4 or 5 discs and try it out until you get the best result. Q. 4. Will a rotary quenched gap give a shrill whistling spark? A. 4. Yes; if properly designed. Q. 5. Do ships use a rotary quenched gap? A. 5. Most of them do. They also use a 240, or even a 500-cycle generator to get the tone they have. Q. 6. Is the safety gap of a transformer connected across the secondary? A. 6. Yes, thereby making it in multiple with the leads going to the other transmitting instruments. MAGNETIC DETECTORS S. S., Stamford, Conn., asks: Q. 1. Is the secondary of a ¥%” spark coil suitable for the secondary of a magnetic de- tector? A. 1. We are not familiar with any form of magnetic detector which employs a sec- ondary similar to the coil you mention. Q. 2. Where can I get information which will describe the various types of magnetic detectors? Could you give me this informa- tion in the Questions and Answers Column? A. 2. No; it would be entirely too long to give here. Section 9, Chapter VI, of the sec- ond edition of “The Principles of Electric Wave Telegraphy and Telephony,” by J. A. Fleming, is devoted to this subject and covers the matter quite fully, both in regard to theory and construction details. Q. 3. Is a magnetic detector easy to con- struct and operate? Is it very sensitive as compared with crystal detectors? A. 3. The magnetic detector works fairly well on long wavelengths, but is not very sen- sitive on short wavelengths. In its commer- cial form it is very simple to operate, but the usual magnetic detectors of amateur con- struction are far from satisfactory. We great- ly doubt if you would be repaid for making one. ARC LIGHT INTERFERENCE R. A. B., Columbus, Ga., asks: Q. 1. Does an arc light if close enough t a receiving set have any effect on it? From 7.00 P. M. until 4.00 A. M. while the arc light is burning, which is located about 50 feet from my house, I can hear a hum which near} downs out all messages. y A. 1. It is quite probable that the arc light is what is causing the interference. If there is a ground on the arc circuit this hum will be very disagreeable. The overhead wires make a very fine aerial for the system to ra. diate waves from. Q. 2. How can this effect be avoided? A. 2. It is practically impossible to avoid jt It can be relieved somewhat by placing your aerial at right angles to the arc light wires and by using a very loose coupling. Yoy have our greatest sympathies for your misery for misery it is. If any amateur has success. fully found a way to overcome this trouble we would like to hear from him. AERIAL TROUBLE F. J. E. S., Wilkes-Barre, Pa., asks: . 1. My receiving instruments are 38 feet from the ground and my aerial is 40 feet higher. Of late my receiving instruments have been working poorly. Do you suppose this is caused by the erection of a 16-story build- ing about 300 feet from my station? My aerial is flat top and but 20 feet long. A. 1. It is entirely probable that since your aerial is but 20 feet long and that a 16-story building contains a large mass of steel that it is shielding your station. It would be well to determine if your detector has not deterio- rated. Also look around for a loose connec- tion. Q. 2. Would I gain anything by moving my set up three stories? 2. Probably very little. TUNING COIL WINDINGS R. A. de V., Atlanta, Ga., asks: Q. 1. With an aerial whose wavelength is approximately 600 meters what is the size and number of turns of bare wire I can wind ona coil 3” in diameter to get the greatest possible wavelength without using a loading coil? A. 1. For all practical purposes the limit comes with the size coil you can find room for rather than the maximum wavelength. There is, to be sure, a wavelength above which your aerial would be too small to respond, but that wavelength would probably be somewhere in the order of 10,000 meters, so that you need have no fear of any tuner of reasonable dimensions being too large for the aerial. Wind the coil with No. 22 bare’ wire and by making the coil about 18 inches long you should receive 3,000 to 4,000 meters without using a loading coil. Q. 2. How long a wavelength could I re ceive with a suitable loading coil? A. 2. You would probably be certain of getting as high as 10,000 meters.

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THE BOOK OF WIRELESS. By A. F. Collins. D. Appleton & Co. New York, 1915. 222 + xv. pp., 219 illus. $1.00. This treatise on the elements of radio teleg- raphy will be of interest to beginners in wireless work. The author’s intention is to provide sufficiently clear diagrams and de- scriptive matter to permit the veriest amateur to build, install and operate a successful “wire- less” station; in this he seems to have been successful. The apparatus illustrated and dis- cussed is all of well tested types and may be depended upon for reasonably good opera- tion when properly manipulated. The book is divided into three parts, the first five chapters concerning a small wireless outfit, the next four covering a long-distance wireless set and the remaining three being de- voted to the induction coil, transformer and electrolytic interrupter. Chapter IV on “Learn- ing the Morse Code” is of particular value to the novice in radio work. A dictionary of technical words and phrases is included as an appendix. The paragraphs on adjusting the tuned transmitter and receiver and on the use of a hot wire ammeter are entirely too brief and sketchy to be of much use to the amateur who has faithfully followed the constructional di- rections and thereafter attempts to make his set work. This should be remedied in future editions; in the meantime the student will find much else of help to him in the present volume. “2 EXAMPLES IN ALTERNATING CUR- RENTS, VOL. I. By F. E. Austin. Pub- lished by the Author, Hanover, N. H., 1915. 223 pp., illus. by diagrams. A book of numerical problems in applied alternating currents, the answers and the methods of solution being fully stated. The first 41 pages contain an outline of mathemati- cal processes from geometry and_ trigo- nometry through differentiation and integra- tion, and will be found to be an excellent basis for review or reference. The generation of alternating em.f.’s is then taken up, and the text proceeds to explain various computations for both sine and non-sine waves. Inductance, power factor, inductive impedance, parallel cir- cuits, capacity, resonant current values, and current-voltage relations in complex networks are then discussed. An appendix of tables and an index are included. As a whole the book seems reasonably accurate. Radio engi- neers will find the work useful. It must be borne in mind, however, that the author has not considered the radio point of view in all cases, as when on page 201 he says: “It is Reviews of New Radio Books evident that at least two undesirable features attend the condition of resonance: excessive pressure or excessive current.” * * THE YEAR BOOK OF WIRELESS TE. LEGRAPHY AND TELEPHONY, 1915. Compiled by The Wireless Press, Ltd., pub- lished by The Marconi Publishing Corpora- tion, New York, 1915. 802 pp., 37 illus., and map. $1.50. The third issue of this almost encyclopaedic annual is some 40 pages larger than the edi- tion for 1914, although by the use of thinner paper the bulk has been somewhat reduced. The book is alone in its field, and is the only collection of material in which one may find the laws and regulations governing radio teleg- raphy throughout the world. To print even the complete table of contents would require much space; it should be noted, however, that the London Radio-telegraphic and Safety of Life at Sea Conventions are given fully. Over 200 pages are devoted to four lists of the radio stations throughout the world, and a five-lan- guage technical glossary, a dictionary, and col- lections of standard formulae and tables cover nearly 100 more. Eight new articles are con- tributed and are of interest from engineering and military viewpoints. The Marconi com- pany of England is to be congratulated upon the production of a Year Book so useful as this, which, though naturally not entirely un- biased in treatment of work done outside the Marconi organization, should be in the hands of every person interested in the international scope of radio-telegraphy. * OPERATORS’ WIRELESS TELEGRAPH AND TELEPHONE HANDBOOK. By Victor H. Laughter. Frederick J. Drake & Co., Chicago, 1909. 180 pages, many illus. Price, $1.50. The author prepared this book with the in- tention of providing a volume to guide the progress of students taking up the problems of wireless telegraphy with the aim of becom- ing expert operators. It was therefore neces- sary for him to follow a course midway be- tween the highly technical and the feebly ele- mentary treatments adopted by some other writers on the subject. The first two of the ten chapters take up the elements of electricity, but the remainder of the book is devoted to practical discussions of the various American arrangements of wireless apparatus which have so long been called “systems.” Both wire- less telegraphy and wireless telephony are described, and in the main the book should prove interesting to the group of readers for which it was intended. 861 — i AAA AAAS )

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Dust Mop Cleans Corners NEW dust and polish mop has been found useful be- cause of its ability to clean corners behind furniture. The main feature of this mop is the two arms which project out, one on each side. One or other of these arms may be pushed into a small place which could not be reached by the usual round or oval mop. any Portable Wardrobe WO pairs of parallel arms are pivoted on the inside of a suitable frame and their upper ends are tilt- ed inward. Pivoted | to these upper ends isahorizontal frame. When in use, the arms are tilted outward and the horizontal frame is extended to its utmost, making a siza- ble rack for suspending wardrobe hang- ers. This device is suitable for a ward- robe trunk, or for closets where the space is limited. A Dancing Shoe for Fox Trotters N attachment for the soles of shoes to prevent | slipping is made by | cementing a thin /\disk of rubber to the shoe. A larger disk fabric with its central portion cut out to expose the major portion of the rubber disk is fastened securely over the edges of the rubber disk to the sole of the shoe, forming a protection which keeps the rubber disk securely in place. What’s New and crevices and: 862 in Patents A Device for Sampling Grain A GRAIN trier or tester to enable inspectors to obtain samples eas- Zily from various parts of a loaded grain car is made in the shape of a long, hollow pole. A number of ports or openings are formed in the side of the pole for the purpose of admitting grain at different points. These ports are opened and closed by means of a valve, the controlling device of which is in the handle of the pole. When the valves are opened, the grain flows into the hollow pole, and upon closing the valve, is kept there so that it cannot mix with the grain hela in other sections of the device, Autoist’s Lunch Box COMBINA- tion lunch- —_ a eon case and table is io POL (: mE made in the form of a suitcase, so that it fas ae Aas a may be easily strap- ped to the back of an automobile. When the cover is lifted a set of boxes is brought into position con- venient for handling, and by means of a catch the cover is fixed in a position suit- able for a table top. Thread Holder Fits Finger N_ improved thread hold- er, especial- ly adapted for use by leather workers in shoe or harness work is provided with a ring so that it may be conveni- ently placed upon the finger of the worker. It is also pro- vided with a tension device for feeding out the thread from an enclosed spool to a needle or some other instrument. ° jud:

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Light in Cane’s Handle HIS device consists of a flash light built in the handle of an umbrella or a cane. A cylindrical bat- tery and a bulb, with reflector and lens are contained in the handle, and the switch is in shank. The device ‘‘ should be of use in judging key holes at night. Catching and Holding Hogs A N_ invention embodying a device whereby hogs may be caught and se- curely held while ringing them is made somewhat in the form of a bicycle pump. On the outside of the tube acord is fastened. The other end of the cord forms a loop and is fastened to the end of a rod which extends through the tube. To the other end of the rod is affixed a handle. The loop is caught over the ear or snout of a hog or other animal and the rod is pulled back. This causes the loop to be drawn tightly around the snout of the hog. This Invention Slices and Peels Pota- toes at the Same Time COARSE metal screen is held in a disk which is placed over the top of a proper recepta- cle. The device is equipped witha plunger, which pushes the potato on the screen. In operation, the potato is boiled in order to toughen the skin and halved. It is then placed upon the screen, fleshy side down. The fleshy portion of the potato is forced down through the mesh, with the result that the mesh cuts the flesh into slices. The skin remains on the top of the screen, from which it may be easily removed. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 863 Chilling the Ardor of the Setting Hen VERY seri- ous problem is often presented to poultry raisers by hens who arege anxious to set on, rather than lay eggs. Porcelain eggs waste too much of the hens’ time. The device in the illustration employs the old porcelain eggs; but they are so con- nected with a tank of cold water which is made to flow through them in a slow stream that the hen’s enthusiasm is quickly cooled. At once the hen realizes that its heat is useless for warming the eggs; she leaves the nest and becomes a normal egg-layer practically cured of the desire to set. The flow of water is regu- lated by means of a small valve. Plug for Glue and Paste Tubes STOPPER is made for glue and paste tubes with a curved blade for spreading the ad- hesive material over the desired surface. The handle is so weighted that when the spreader is laid upon a table the spreader projects up- ward and does not smear the table with glue. Automobile Folding Bed COMBINA- TION auto- mobile bed and baggage holder consists of pipes so arranged as to form an_ exten- sible frame. This frame is fastened to the rear of an automobile and, when ex- tended for use as a bed holder, has two legs which are dropped to support part of the weight. It is claimed to be equally convenient as a baggage holder. The frame is contracted, and a hinged portion folds up to hold the baggage in place.

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864 Blinds To Teach the Touch System of Typewriting . N eye shield for use in teaching students the touch system of typewriting is made to fit the face below the eyes ; and entirely to ob- struct the line of downward vision between the eyes and hands of the wearer. The shield itself is adjustable to suit the user. It is composed of two equal parts, joined by a system of slots. A Shaving Brush with a Drip Cup HE annoyance of dripping water has been abolished for the shaver by a new lather brush which has recently been placed on the market. The addi- tional device which is attached to the brush is a rubber cup, placed at the brist a position that all water running from the brush is caught. As a result it is possible to shave without getting the fingers soapy and wet. A Toy Blow Gun with a Magazine TOY blow gun, to which is attached a magazine hold- ing a quantity of small shot or other ammuni- tion, is made so that shots may be rapidly fed into A hole is made in the top of the barrel and another in the bottom of the magazine. When the magazine is slid forward in a groove so that the two holes correspond, a shot is dropped back, the hole is sealed and the gun is ready for the discharge. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Rock and Churn Butter HIS device permits the operationofa churn by means of a shaft connected to the rocker of an ordinary rocking chair. The motion of the chair, by means of the connecting rod, imparts succes. sive thrusts to the studs in a wheel at the top of the churn, thus making the wheel turn slowly at each thrust. This movement results in reciprocating the dasher in the churn through the agency of an eccentric disk and strap connec. tions between the dasher shaft and the power shaft, upon which is located the studded wheel. A Mechanical Sauerkraut Cutter O sauerkraut ’ makers, the vegetable cutter shown in the il- lustration will have a decided in- terest. Essential- ly, it consists of four steel knives mounted at right angles upon a wooden revolving frame. The cabbage or any other vegetable to be cut is placed in the feeding-box. With slight pressure from the hand of the operator, the cutting is rapidly completed. Feeding Nails Automatically NAIL holder [Ss : AA or container which automatical- ly feeds the nails into a slot, in a ver- tical position, ready to be con- veniently and quickly withdrawn for use, is made with a breast plate’and hooks, so that it may be strapped to the body. The nails are fed loosely into the hopper, and are held ready for the artisan by means of the groove, or slot. As the nails are withdrawn from the slot, a. vibratory spout rebounds and releases an- other nail from the container to take the place of that which has been just re moved from the slot. . te

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE - Bing’s Mechanical Toys ——— i a lm ~ . BOYS, HERE SS Vy ARE THE MOST WONDER- YS y FUL ELECTRIC AND MECHANICAL ‘\N\ my// TRAINS YOU EVER HEARD OF, SOLD Vf UNDER A WHOLE YEAR’S GUARANTEE. \ The most fascinating and educational toys of the age are these \ working models of actual trains. All who see them marvel at their \ perfect operation and life-like resemblance to the great railroad trains of America. Electrically-driven “Twentieth Century Limited” The power for this beautiful train is supplied either from your ordinary house current or from dry batteries. This train which is Nearly Four Feet Long consists of extra-heavy locomotive, tender and three cars. Twelve pieces of third-rail track, specially banked at the curves to prevent derailment, complete with wiring connections, five-speed regulator.and book of instructions, are supplied with it. VARIOUS SIZES AND PRICES Thetrains are made in various sizes priced at $4.00, $5.00,$8.00, $10.00 and $15.00. All our trains are fully equipped. MECHANICAL POWER ALSO If you do not possess facilities for electric power we have models of the same trains eperated by mechanical power at $1.50, $2.00, $3.00, $5.00, $7.50, $10.00 and $15,00. GUARANTEED FOR TWELVE MONTHS All the trains are sold under our guarantee that they will operate perfectly with proper use for twelve months. You could get no fairer proposition. BING’S TOYS are known throughout the country for quality. If your store cannot show you these wonderful trains, send your check for one you want to JOHN BING 385 Fourth Ave., New York. He will personally see “og that you are supplied. ; RQ. Backed by a solid guarantee; Read it! When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE You know the ancient fame of CYPRESS but do you know its uses zoday, and their significance to you ? CYPRESS is the wood of Scriptural history, and of romance; CYPRESS was the mystic wood of mythology—and it was the reliance of the sturdy builders of early America; CYPRESS always has been a magnet for those who have wrought senti- ment and beauty into useful things—and CYPRESS is today the staple wood of the hard-headed calculating buyer who seeks the most /asting values for his lumber-money. This concerns YOU—if you like to avoid repair bills on anything made of wood. It was of CYPRESS, according to Pliny, that the famous statue of Jupiter was carved; it existed more than six centuries without a sign of decay. The historic Gates of Constantinople were of CYPRESS; they were on duty for eleven centuries without a furlough. The CYPRESS doors of ancient St. Peter’s, in Rome, were in astate of perfect preservation when removed by EugeniusIV; they had been swinging on the faithful for twelve centuries. The only Egyptian mummies that survive intact and unblemished are those whose executors filed ‘them in CYPRESS receptacles. To bring the record nearer home—there was Thomas Lyon, who in 1640 built him a house in Greenwich, Connecticut. He put CYPRESS shingles on its roof and sides. With no exterior repairs of consequence, this house is today occupied as a residence. THIS WAS AMERICAN CYPRESS — the kind we own and cut and are selling you. CYPRESS is in truth ‘‘the wood eternal.’”? He who uses Cypress builds but once. If you are putting up a palace or a pasture-fence, and want to build it “‘for keeps’ —USE CYPRESS. There is an unusually liberal education (and a wonderful investment value for you) in the CYPRESS advertising — and in the detailed information and reliable counsel to be had promptly, WITHOUT COST, if you will WRITE US YOUR OWN NZEDS (big or little), and ASK YOUR OWN QUESTICNS of the “All-round Helps Department” of the Southern Cypress Manufacturers’ Association 1249 Heard National Bank Building, Jacksonville, Fla., or 1249 Hibernia Bank Building, New Orleans, La. INSIST ON CYPRESS AT YOUR LOCALLUMBER DEALER'S. IF HEHASN’TIT, LET US KNOW IMMEDIATELY ri “HE WHO BUILDS OF CYPRESS LUMBER BUILDS BUT ONCE” When writing to Advertisers please mention Ponular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

POPULAR SCIENCE MONTHLY AND WORLD'S ADVANCE

Volume 87 Waldemar Kaempffert, Editor No. 6

Contents for December, 1915

AERONAUTICS Page iliti ers to be Trained at Army Aviation School..... 721 ona ga Aeroplane under Fire a Mile in the Air....... 765 The Passing of the Rotary Motor............ssesseeeees 768 Death in Five-Sixteenths of an Inch..........seeeeeseeees 782 A Wirelessly-Controlled Aerial Torpedo..........+.s2000 783 American Aviators with French Army........sseeeeeeees 795 ASTRONOMY Suns and Worlds in the Making..........seescseseeseees 805 AUTOMOBILES AND AUTOMOBILE ACCESSORIES ing Rain-Spattered Windshields by Electric Heat...... 709 Drying F the Rim Oe SS ee eae 20 UNO COE FORO PIOSC so. o5 5 oc ns ssinnisc cewscscievesioes 721 Removable Bodies Speed Up Lumber Deliveries........... 758 SMR RMIIRE MIMIC ores 5 0:s1csesdiesnisiais sieceis ateiessinielavereioieiels/sicielsleiaisie 760 New Crank Lock for Light Automobiles.................. 766 That Small Farm Tractor of Ford’s.............eeeeeeees 780 The Antics of Maud, the Motor Mule................0008 782 Motorcycle as Cart Horse..........sssccccccecssccccecs 783 Diictor Car with & Boat Body... .cccccccesesecsececes 784 PUN ae o a9 a 6 cw ave 6:al0)e‘os6 oieiaie(<co:e: igre 790 To tren Autosts Out of Rute.!........ccccescsescseccee 791 Fender Made for Use on Pleasure Cars............2.e000: 800 Delivering Locomotives on Motor Trucks...............+. 804 ’ Tool Simplifies Putting on Tire Chains.................. 804 Another Device for Dimming Auto Headlights............ 809 Strap Pad Oiler for Auto Springs.........cccccccscsececs ee nee eer New Front Spring for Small Cars. ..... Overhauling Sear Car for the Winter CIVIL ENGINEERING Why the Slides Slide at Panama..........cccccccccceces 707 Ree ORII OR OONEOEE oc. a's. s:aisie ¢ psdisise ses eciecesioe 710 Building the Largest Single Span in the World............ 711 Saving the Home of Washington............cceeeeeesees 722 The River WEINURIEEROWIMCODN 5. 0.<'0:6.s.0:0:sisinelas:sibe'ciereeeere% 736 The Highest Dam in the World. ........ccccccccccccece: 754 Portable Asphalt Mixing Plant.......... Ralkgaccsmiecicesis 801 ELECTRICITY Seeing the Panama Canal in San Francisco.............005 710 MMT IITE Sa os.. csic'e.s sic cieeeesauiseebesecsee 736 Loading Dirt Trucks Electrically. ......cccccccscscececcs 758 Electric Loading System for Trucks........ccecececececes 764 A Skeleton Danger Signal...........ccccccescccccccccce 782 PENI RO METI ooo ose. s.o.o's:s-c:c-cresiecisieeecioseeeeesics 792 A Waterproof Sensitive Telephone Transmitter............ 801 FOR PRACTICAL WORKERS Repairing Measuring Glasses..........cecsecceccceeccecs 797 Stationary Ladle for Dipping Wires.........e.eeceeseeees 825 Repairing a Starting Box with a Lamp.............0ee005 825 Generating Gases in Large Quantities............eeceeees 826 A Tool for Bending Tubing.......... aces eeleiowenecinsiens 826 Show Card Ink............. Maia cisdiaieinaicia sisi aojelewieee se 826 Home-Made Worm Wheels and Screw...... Miele eaisiacoeee 827 Kuti ing ag, Comanens i ieieisisieiaisioe aiase(celiecealecrs pod . Open Circuit aj ystem..... aiewassesiecececive Substantial Top for Work Bench. .......0..20ccoeccccee 828 sietos ber OS oe Sere Suioccovicsomenins 828 To Mark Gauge Glasses Neatly.......... Songabewcusle ans 828

Page Hardening and Tempering Steel Tools...............0.. 829 Adjustable Drawing Trimmer..................+20------ 830 MIMEIEPOMFS oie orale Soca c si so Ce oocin e 830 OWE SD GENOME CORNET. «5.4.0.5 << sio0sceniisvec scons gene 830 Cross Cutting Gauge for Band Saw..............065..... 830 Cement for Mending Steam Boilers..............0+...-.. 830 Overhauling Your Car for the Winter.................... 831 Pa Comngemc A PAG. <5 ooo sso ncceoeceeiedesccecccs 840 Prolonging the Life of the Storage Battery................ 840 Simple Substitutes for Bunsen Burner..........0..0000005 840 Cement for: Steams) Pines... 2.4< 020s «.cccscsccocccseccecte 840 A Home-made Tank Heater...........cceccceccccecccece 841 CBee OVENS cia sios sacin asco ocideececeinneecusscck 841 A Slotted Screw Driver............0..cecceecee coco OME To Find How Long Hammer Handle Should be. .. 841 A Strong Cement for Leather................ .. 841 A Home-Made Filter for Outdoor Use......... .. 842 To Keep an Auto Jack Level............... . 842 An Improved Liquid Atomizer................. . 842 CTL’ ee ea o .. 842 UNLOVE SeMAG AVERTED. 50 0c. ccccsccecsccesccved once 842 PAYG SOREN WEE PENCNS S05 «:. <.ccrscicicioccsccoeerccewocnce 843 To Make Copper Oxide for Batteries............c0ec0005 843 ROP OiO PMO NEN. oo. 6.0. <:5 0.000 scccsccecceeeacewdse 843 To Make Sharp Corners in Sheet Metal..............000+ 843 An Automatic Telephone Lamp.........ceccecccecceccce 844 A Home-Made Hand Klaxer.......ccccceccecceccccccece 844 A Film-Developing: Hint... .......<scccccccocseccccsdacctdbe 844 Removing Solids from Filter Paper..........ccccceeseeee 844 SHINGO) POMEIGY SHIICREOE J. 5.0 sos ses iccaceckecedewaceececs 844 An Electrical Egg-Beater..........cccccccccccccccccccce 817

Electric Lighter for Gas Stove.......ccccccccoccsccccece 817 Indelible Ink for Marking Clothing.............ccececees 817 An Effective China or Curio Closet.........ccccccececece 818 Clearing Ready-Mixed Paint.......... 818 An Ice-Card Holder... ............008 819 A Home-Made Gas-Jet Heater........ 819 To Remove Paint Spots from Windows. . wee O19 Wire Broom Holder...............ceecees Sioa Holding a Window in Place. .........cececeees ... 819 How to Make a Match Holder.........cececcececccccccs 820 Some Stain-Removing Recipes.........ccecceececceecece 820 Lengthening Life of Window Shades..............00.0005 820 What a Woman Should Know About Electric Connections.. 821 Lengheretter’ Pench «COWES... ce «6's v0 sinasecescvececncecacs 821 ere Extiniguimier: Laas o..5..000c000cnvecevcssscecwiaes 821 Gas Fleated Steamt RAdiAtot. .<0cccccceccccvecccsecccess 821 ge OU Eee eee re 821 Damper Opened Automatically by an Alarm Clock........ 822 To Drain Underground Pipes............csccccccececees 8 To Discourage Prowling Dogs and Cats.........ccecceces 823 Closet Converted into Magazine Case.......ccecccccecece 824 A Saree WakerpOOns.... .........cccacccececcceccccces 824 How to Remove Indelible Ink....... Ripua ve qusieceaeemene 824 Three Ingenious Door-Checks........ccccccccccccceccece 824 No: Make Lacquer for Beate:... <0 .ccscccceccocescscctes 824 HOW THE WAR IS BEING FOUGHT The Fatal Hum of the Submarine............ceccecececes 713 Trawlers in War and Peace...........sccccsccecccccccecees 727 How the War is Being Fought...................0005 737-753 Germans Furnish French with Excellent Bomb Throwers... 762 Earthquakes Caused by a t MMO Gc cc codhetucreudee 811 Shrapnel for Destroying

Copyright, 1915, by The Modern Publishing Co.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE CONTENTS FOR DECEMBER—Continued |. MAKING HOUSEKEEPING EASY Page Page A New Kind of Extension Dining LSS ea ee 788 | Chilling the Ardor of the Setting Hen.............cce000. 863 Kitchen Cabinet Can be Adjusted in Height to Suit the Plug for Glue and Paste Tubes .. 863 eee nee 789 | Automobile Folding Bed............ -- 863 Pasteur Milk for Babies at Home...............2-+++ 797 | Blinds to Teach the Touch System of Typewriting oon . PE UE ADORE, 5 4 55s akwn nas veiede sess 798 | A Shavi a with y BES SID oss occcc cca se ... 864 A Nat Netural Substitute for Eggs in Pastry Cooking.......... 807 Be Toy Blow Gun with a Magazine.............. os 864 Begs ee OE ee er eee -.. 864 MECHANICAL ENGINEERING . Mechanical Sauerkraut Cutter. ..........eseseeeeseees 864 How the Submarine “F.4” was Lifted Out of Three Hundred - ceeding Nails Automatically...............sccsccesceece 864 eet PTT TT TTT TOPE E ECT TC E RELESS TELEGRAPHY AND TELEP’ SUPONNERNM BURDE. 5... 5.05 .05<0cssccevoscesccsvc 755 wi HONY Water was eons’ a Thousand Years Ago............ 756 | Wireless Telephony Simply Explained.................... 723 ae oma! a H a ts ee WOR | Mmotiier © ocket Wéarckess. .....s. 5. 2s00csecssecccessenen 735 le i... eee 845 A tah ee . that will Not Work............ BP Meme MERE NRRVERIROUB 655. 0.0)5.0.5. 0:0. 5.0:5.0:0100 6500600 GC ce PRRTRNNEON BUPO AINE SOOEE. os 5 5. 5.5.0sosv'nisie sc dpe ccemecee 848 MINES AND MINING mned medenns Sar the mised of eaten seme 848 More Efficient Coal Mining.............¢escceseceeeeees ae oe Stray Steers Cause Discovery of Cinnabar Deposits........ 788 Wide Chavet a Mi VES ieee Aluminum the Most Abundant Metal.................--. 798 | A Crystal Detector. . Natural Gas in the United States. .............0eeeeeeees 28 Weare ak aes Staton. Gail. scale esate cae A Contact for Crystals. ee 852 MODERN MEDICINE AND SURGERY Und: Oscillation Systems of Radio Telegraphy.. Seceaae 853 AND INDUSTRIAL HYGIENE — nee ON SR ee = Adjustable Table ine Home Exercise Convenient....... 787 oma Amateur Radio Association.............. vies ae 856 Appliances and ae Protect Workers.......... 794 | The T UNDUE So ooo iG sca keas oe kinoe come 856 oe a OSS ee eae 803 | Radio ub DMB ERC cris ccs SicSivieeiswwea es eeweeeeee 856 An Unspillable Medicine Bottle PA Moleeay Warsnble KGOMGENEET. ... .. .s.0csiccnccescceccceutac 857 Receptacle Resistance Unit.............ccccccceees 85, = vot piace OE ORD ORF iii s- Talsaiaieoca isis ee ee 85. ‘erminal Connections for Condensers.............eseceee 857 Frem Swimming cece How to Improve the Sound of a Buzzer.............00005 857 “Movie” Seats for Children . Plans for Radio Club in Boston.............cccecceccece 857 A Booth-Controlled Electric Piano Player “ What Radio Readers Want to Know............ccccececs 858 Night — Photography in Inaccessible Places 7 Reviews of New Radio Books............+00+ vavneiesiewae 861 y. Making. Motion Picture Cartoons with Ammonia Pens... . 810 MISCELLANY SCIENCE AND THE FARM Protecting the Mails Against Letter Box Thieves.......... 709 ids Curious Vehicles Used in Cuba...............ccececeeees 710 , A Binder on Skids. ..............seeeeeeeeeeeeeeeeees ee ES cuccbennesensecunneennennel 757 | A New Grain Sampler. -...... 5... .-0.seseeeeeeeeeeeeees Oe EE cn cunaycsarceecnessennderseunn’ 759 oes, ne ey lh ape Oe so sicoscicsuvonsnnensesseacnaeden 759 Hens Must Exercise for a Drink Rbissh vies sebeex sie 795 aes UNE OE IRBID 6.66.5 6.6 545.0010 :0 000 0 0c ewsinewenien 760 The Government's “Canning Clubs”..............+++++-: 800 | No Signboard Like This.......-....:.++scccceccoceeeree 760 Raising Cucumbers a Foot Long..............0.eee0e0e% 802 Hub Step for Wagons. «ee Clay Brathecen 261 very State in the Union es Clay Pe SHIPS AND SHIPPING Clock from Stove Repairs... ..........ssssesescesevececs 761 A Business Chance for Motor Boat Makers............... 757 | Walls are Built Like a Floor................ssseeeeeeeee 763 NE oo ass ckawasssseviicnsesess ee WIE NINES 5.5.05 fos 5 Gc: 450 0:0 sais ew sina eis 'oaieneeceise 767 Motor-Driven Schooner for Coastwise Trade.............. 779 | M ical Ndaythings OF TOUAY.........00.00s0cg0cesseaes 768 A Life Boat that Cannot Upset...................00005: 811 | Cement Makes Lively Advertisement... ............0000-+ 784 Handling a Thousand-Pound Hogshead................--- 784 WAR PROBLEMS IN AMERICA Moving louses to Escape Ocean Breakers..............-- 785 The U. S. Army's New Water Works.................-. 766 MAM MRR 2525-5 5.0.5 5i'6.0 o'00'6 b 00'e aoe eee 788 a Torpedo Boat with Stripes.........------.----. 781 Ou id to Birds’ MMS FRM. <6 <s.siss sce sicicic vic sinencnanm 791 Sixty Million Candlepower Searchlight................... FRG | RMN SUR UOMNS ROD 8... 8... occ ccvccncvescceeshs 792 ikki anata... ................. 789 | A New Safety-Razor Edger.............0seecccccccceees 7% . ee aes pe PEACE ncniekas boiue ou esse SR eResNee 4 WHA TENTS use Street Lights eee TS NEW IN PA Mail Box is Ornamental . 7% ee 862 | Novel Street Lights............. . 79 ee Seer ee 862 | A Chandelier of iaaies . 802 A Dancing Shoe for Fox Trotters........ ... 862 | Registering Gas Meter Readings with the Camera. . 806 A Device for Sampling Grain.......... ... 862 | Raising Five-Thousand-Dollar Silver Foxes....... . 808 Autoist’s Lunch Box........ oe ove OR | A Teme OVINE EMVEIODE. ...5... 2. .0cccccccesees oo ca Thread Holder Fits Finger. = ... 862 | Patented Christmas Trees. ..........ssseeeeeeseees cosen an Light in Cane’s Handle. . Senchoieuns ste 863 The Fickleness of Watches Explained ............eeeeee0 814 Catching and Holding Hogs. ee Lt es PE ADahGe ae eau ceoreenie 863 a ey way SN OC Seer 815 This Invention Slices and Peels Potatoes at the Same Time.. 863 | Removing Snow by Dissolving it............+seeeeeeeeees 816 Magazine issued monthly. Yearly subscription in U. S., $1.50. New York City and Canada, $2.00. Foreign $2.50 in Gold. SINGLE COPY, 15 cents. : Porutar ScteNce MonTuHiy and Wortp’s ApvaANcE may be had at all news stands in the United States a and Canada; also at Brentano’s, 37 Avenue de 1’Opéra, Paris. Forms close the twenty-fifth of the second month preceding date of publication. Advertising rates on 4 a —.. _ as second class matter at the New York Post Office, under the Act of Congress of arch 3, The tl of ed Magazine are copyrighted and must not be reprinted without permission. H. J. Fisher, President; CRs, Vice-President; O. B. Capen, Secretary and Treasurer. THE MODERN PUBLISHING COMPANY, 239 Fourth Avenue, New York City

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

SE —————————— & This Set ee

Because I want ambitious men to become high salaried Draftsmen through my practical working training—therefore: I Will Give You The Chief Draftsman of a large and well-known company will give you this complete draftsman’s outfit absolutely free. It does not cost you a i penny. Besides these Imported regular draftsman’s instruments shown here, I also give you abso- lutely free a 20x25 inch drawing board, a 24-inch T-square, a draftsman’s triangle rule, supply of drawing paper, 2 triangles and French curve, pencils and erasers, drawing thumb taeks, etc., in fact a complete and first-class regular Draftsman’s Working Outfit as soon as you enroll, This is just the same kind of an outfit I use myself. Genuine working instruments. You could not get this outfit for less than $15. But now on this special offer, I will give it to you absolutely free. And Train You For a $200 Position Iam Chief Draftsman of an old and well known company. There is a con- stant demand for trained draftsmen all over the country and 1 will give you just the kind of train- ing that will qualify you to hold one of these big paying positions. $125 to $200 a month straight salary is an ordinary pay for a good draftsman. I will give you just the kind of training that you

SPECIAL! For a limited time I am making a special price offer in order to com- plete a new class ready to start. Send for free book at once, today.

of Drawing Instruments Xu ° need fo hold one of these fine jobs, right in your own home during your spare time. Start earning money as soon as you are my personal student. I know the kind of training that you must have in order to get the highest salary— and that is just exactly the kind of training that I will give to you. During the last twenty years I have trained some of the highest paid men. Their suc- cess in the profession is well known. You can do as well—or better than they. Send Me the Coupon New Book |

Put your name and address in the SS Cae a aaa coupon or 9n a letter or postcard now and send to i me at once for my new book “Successful Drafts- manship.” Find out about the golden oppor- tunities that await you in our profession. Fin Out how you can get just exactly the kind of training that you need to hold a position paying from $125 to $200a month at once. Absolutely no obligations in getting the book. Just put your name and address on the coupon. But send it now immediately while I am making this special offer. CHIEF DRAFTSMAN DOBE Div. 1409, Engineer’s Equipment Co., Chicago i RRM 5 NN RISE SE ceiatnmenuniil Address. .ccccccccccccccccccassccccenasccccoccecccccccense® ——<——— Chief Draftsman Dobe Engineer’s Equipment Co. Division 1409, CHICAGO, ILL. é Without any. obligation to me whatso- ever, please mail your book “Successful Draftsmanship,” and full particulars of your liberal ‘Personal Instruction” offer to a few students. It is understood that I am obligated in no way whatever.

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When writing to Advertisers please mention Popular Science Monthly and World’s Advance,

Page 168

POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Che NEW YORK ELECTRICAL SCHOOL New York ELECTRICAL School Gives you a complete train- ing by actual practice. You get the knack of “HOW” together with the theory of “WHY” and the best busi- ness methods used in the World of Electrical Ac- tivity. The N. Y. Electrical School is the pioneer and premier school of the “Learn by Doing” -method. When you have com- pleted this Course you shall be fully qualified to handle ALL branches of Electrical industry. The equipment of this School is un- equalled and up-to-the-minute. No preparation needed to become a “learner” in this school. You can start to learn on any day of any week throughout the whole year. Drop a postal card or phone for Catalogue. Visitors heartily welcomed. N. Y. ELECTRICAL SCHOOL 40 West 17th St. New York City Increase Your F ffici es The secret of business and social suc cess is the ability to remember, lean. make your mind an infallible classifies index from which you can instenéi select thoughts, facts, figures, names. faces. Enables you to concentrate, develop, self -control, overcome bashfulness, addressan a : Easy, ~~, bee result of 20 years’ en | perience in eveloping mem ‘4 ands, Write today for cory of ae ““How to Remember” and C Iniensely Interesting Memory Test 708, also how to obtain FREE co boul “*How to Speakin Public.’’ oy tng P Dickson School of Memory, 929 Hearst Bldg., Chicago, If, Dyke’s Book—FREE interesting, instructive—tells you Mem . how to learn AUTO TRADE; how ffi)7-45 to become a chauffeur and repair- man.— SEND FOR IT—To-day—Now | L.OYKE, 6B Roe Bidg. St.Louis, Mo mar, Siih"s PObtain a Patent”’ and “‘What tol: ; sent free. rough sketch for free report as \ Pej to patentability. Patents advertised for sale at \ Wisp czPense in Manufacturers’ J ie: WW@ CHANDLEE & CHANDLEE, Patent Attorneys P i¢ = Established 16 years, | ) 1006 F Street, WASHINGTON, D.C Send sketch for free export search and report as to ss. Books on inventions and patents, and ook of references from congres$men, manufac. turers, bankers and inventors sent free, Z JOHN S. DUFFIE & CO. . 608 F St., N. W., Washington, D.C, Hist YOU GLANCED | OVER THE CLASSIFIED SECTION OF THIS IS- SUE? If not turn to page 10 and get acquainted with the numerou advertisers who have propositidiis: worthy of your careful consider- ation. Quickly Learned AT « HOME by the Orgal phic enna (BIC German—French—English—Italian—Spanish -«\ orany other language learned quickly and easily i at Wo. é XS ul — by the Cortina Method at home with Disk (mcsy Cortina-Records. Write for free booklet today; sams @asy payment plan. hin fis Seer tiered CORTINA PHONE 1802 ecco 1090 Ba Show Card Writers Earn $80 to $20 A Month. Learn FREE We will furnish a thorough course in Show Card Writing and Lettering, ABSOLUTELY FREE to introduce our colors if you will put- chase an Assortment of Alpha Colors to use while practicing. Particulars for stamp. ALPHA COLOR CO., Inc. Course Dept 81 East 125th St., New York City When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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SiS =. IE... POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE a —— YCLOPEDIA CYCIOPEDIA -—«CYCLOPEDIA CYCLOPEDIA CYCLOPEDIA CYCLOPEDI of of of of of of APPLIED aualay) APPLIED APPLIED APPLIED APPLIED ELECTRICITY tLECTRICITY ELECTRICITY . ELECTRICITY ELECTRICITY ELECTRICITY Stor 268 This Great Electrical Library SENT FREE FOR EXAMINATION Send the coupon today—now—for your free-for-examination set of the world’s greatest electrical library . The new 1915 edition, just off the press, is recognized by big men in the electrical field as the most practical work of its kind ever published. Covers completely the. generation and use of electricity -for power, light, transportation and communication, including the construction and operation of dynamos and motors, central station engineering and telephone work, as well as wireless telegraphy and telephony and land and submarine tele- graphy. Particularly helpful in its exhaustive treatment of electrical “troubles” and their remedies, Earn $150 to $250 a month Electrical Engineers earn from $150 -to $250 a month. The work is pleas- ant—the hours short. These great books will fit you, in your spare time, to enter this fascinating, well-paid work. No previous experience necessary Cyclopedia of Applied Electricity Contains 3,500 pages, 7x10 inches; 3,000 illustrations, full page plates, tyne. etc.; Bapenoger of heragg 4 os oo formulas; carefully rane Meg aie Pag ac What These Books Cover exed for quick, easy reference. The are substantially = Elements of Electricity — Electrical red morocco, gold stamped, and are printed in large, clear type on special Mensnrements — Underwriters Elee- li ory, jeu. ad ‘ tion Design find Construction of Direct otors— BOC & WEE] mists tianstents | fires edison Secon 7 0 ectric: achinery ~— ectrice sent, express prepaid, for § Lighting— Alternating Current M seven days’ free examination; we... 3 at a seninas if they chinery— Power “Tranenision — Elee- fail to meet with your expectations. If you keep them, pay $2 ff trie Railways “Self-Propelled Rallway seven days after receipt and then $2. month until you have paid ff jij,,—switchboards azd Switching — the special introductory ee of $19.80, saving $15.20, astheregu= § storage Batteries — Applied Electro lar pric> of this new and enlarged edition is $35.00. As this offer is for immediate accept- jj chemistry —Electric Elevators — Elee- ance only, fill in and mail the coupon today. It won’t cost you a cent to examine § trie Welding and Heating— Wireless these books, so get them into your home, shop or office and look them over at your leisure. ee. l~ i tlie and Remember, if you don’t like them they may be returned at our expense and you won’t be traces aria outapenny. One of the most liberal offers ever made. You can’t afford to pass it by. ' ’ With every set is in- § Consulting Service Free wrica‘ssctutcy treo PRR PLoM eke) Shared a year’s Consulting Membership, regular value $12, entitling AAU Melee? ere COM ce you to the advice of a staff of electrical experts. These men are no further from you than your nearest mail box. They M American Technical Society) | stand ready to solve your perplexing problems, to offer sugges- [J pieasesend me Cyclapodia ot Angie’ Electricity tions, to point out the things you should avoid. Absolutely nog for seven days’ free examination. “If I Keep, the limit to their assistance—ask as teat queviaene as you wish for on fe Pd ye month until $19.80 has been paid, when $35 books a whole year. This service alone will e worth more to you than and $12 consulting membership will be mine. Otherwi: ill f d hold book bj the entire cost of the books. j to pear anlse, "Title ont to pale auth Sly anh, : Don’t wait. This means $15.20 savedif you actnow. Remem- Pop. Sci. Mo. 12 15 ber, you take no chances whatever—it costs nothin toi inspectand ll AED ciccsiascecsetestarse secbsacecnsescxcecaues j you are nothing out if you do not care to buy. is offer may ea i mail DRESS cccccccccecccccccseccseccesssessesescese ‘oo ee the —_— today—now—before — As I have had no previous dealings with you, I | eC page. refer you to American Technical Society, Chicago, U. S.A. Lesereceed When writing to Advertisers please nrention Popular Science Monthly and World’s Advance.

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Dee CO LL Sea Ce | ql mT Hi PTOI rt ees ) DER AAA Popular Science Monthly, 239 Fourth Ave., New York. tance for my ad, I don’t want t miss any issue of “your tion as it has certainly duty by me. TOT IAA business, and lots more some of the bigger fellows wh pulling power. CO Gentlemen: Enclosed find remit- than farm, or individual, as well world with a fence around tt when we th iti ir i i i tener “ta - j c orthy sates mi ion _to Be esent before an intelligent, interested turns. Your magazine has al- Adv i é lio it t dvertisements accepted at the rate of 10. CENTS PER later than November 25th. 239 Fourth Avenue 33 HE object of this department is to place the read mediate touch with the newest devices for the ome ye business opportunity or to suggest some service that may be 0 . B a. performed satisfactorily throug one its I don’t want the It will pay the business man, student, experiment reader to study these columns closely. 4 oe ee This department is a ready field for the advertiser who has a WORD, NET. Remittances, in the form of currency, check, money order, or stamps, MUST ACCOMPANY THE COpy G 10 Advertisements for the Janua . are always yelling about their Very truly yours, Kren Epce Company. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE as to offer or seek an unus correspondence. ry issue should reach us not +x 33 New York ‘(= 2S UOOTTOOTTONETCTOTUEN TUONO OUND TNNT TN VOLT TN CONT TTTON TT AGENTS AND SALESMEN WANTED AGENTS AND SALESMEN WANTED AGENTS AND SALESMEN WANTED DON’T BE AN AGENT—You take the money; be your own master. Dave Craw- ford, W. Va., writes; ‘“Made $42.75 first week.”” Smith, Pa., writes; ‘301 in two weeks.”” Bostwick, N. Y., ‘‘Make an aver- age of $10 a day.” We have started hundreds of others. Gray’s outfits $15 and up. Plate Gold, Silver, Nickel, Metal, Etc. We furnish recipes, formulas, trade secrets and teach you the art; work easy. Royal new dipping process. Every family, hotel, restaurant, shop has tableware, jewelry, metal goods of all kinds to be replated. Every other business overcrowded, few plat- ing shops. Send postal, free samples plat- ing. GRAY & Co. Plating Works, 968 Gray Blidg., Cincinnati, Obio. ONE ADVERTISER WHOSE ADVER- TISEMENT APPEARS IN THESE COL- UMS said: ‘‘Our long continued use of your columns is the best testimonial we can give of the splendid results we enjoy. When we add that we are satisfied, all is told.” Why not send in your order now for our next issue. BIGGEST HIT EVER! if Piece Toilet Article Set selling like blazes at $1 with $1 carving set free! Enormous profit! Tre- mendous sensation! Engle made $51 first week. Write quick! Pierce Co., Dept. K, Chicago, Tl AGENTS WANTED: To Adverti8e our goods by distributing free sample to con- sumer. 90 cents an hour. Write for full particulars. Thomas Mfg. Co., 561 North St., Dayton, Ohio. MEXICAN DIAMONDS exactly resemble genuine; same rainbow fire; stand _ tests; sell at sight. Live agents wanted; $50 weekly and up. Write quick for sample case offer free. Mexican Diamond Im- porting Co., Box A, Las Cruces, N. M. “SECRETS OF AGENCY SUCCESS.” Doubles your sales. Increases your profits, Useful present sent to first 100 inquirers. H. O. Abel, Box 134, Hanover, Pa. AGENTS $50 weekly. The only knife sharpener made on correct principle, Won- derful seller. 157 per cent. profit. Simply demonstrate; no talking. General agents can make» $150 week. Particulars Free. 50c sample by mail 25c. Thiele Co., 4 Austin Ave., Chicago. 1,000 PER CENT. PROFIT with our livest novelty on earth from Mexico. Over $1,300 made by one agent in 3 weeks. Big season now on. Lester Co., Box 67, Mesilla Park, N. Mex. WONDERFUL OPPORTUNITY—Start as our agent, become manufacturer. Everyday necessities. Fastest repeat sellers. Marvel- lous profits, Proposition worth at least $40 weekly. Samples free. Fred’k Lobl Mfg. Co., 530 Warren St., Boston, Mass. MULTIPLE-HEAD PLIERS include one pair of handles, six separate heads. Solid steel, tempered, and polished. An _ ever ready Kit for Machinists, Handymen and Home Owners. Exclusive territory. Liberal discount to Agents. Particulars free. Cur- rier-Koeth Mfg. Co., 210 West St., Couder- sport, Pa. AGENTS—The biggest thing out; sell “ZANOL’” concentrated liquor extracts, for making liquors and cordials at home; the real article; saves over 50 per cent; small package, enormous demand; big profits; strictly legitimate; start while it’s new; don’t delay; just a postal today. Universal Import Co., 673 Third St., Cincinnati, O. THE WIFE’S FRIEND—Portable Oil Gas Stove. No valves, wicks, wood, coal or ashes. Steady, intense heat; will boil, bake, fry, roast, cook anything; heat rooms, stores, etc. Simple, durable, saves time, labor, money. ‘Much cheaper, quicker, cleaner than wood or coal,” S. Ludwig, lll. ‘Safe and clean as a lamp,’’ Mrs. A. R. McClellan, Ill. ‘Baked pies, cakes and bread; never saw nicer baking done,’’ Mrs. O. Thompson, O. AGENTS MAKING MONEY. B. L. Heusted, Mich. ‘Out one day sold 11 stoves.”” R. P. Adams, Ia., ordered 3 stoves, then 12. C. P. Schroeder, Conn., 40 stoves one order. Price $3.25 up. Not sold in stores. Show cylinder making gas—people stop, look, get interested—buy. Send postal. World Mfg. Co., 6395 World Bldg., Cincinnati. 0. $2.50 PREMIUM to every $1.98 customer. $7.00 a day profit. Free Selling Sample. Caldwell Specialty Company, Dept. A, Lenoir, N. C. = NOTICE TO MANUFACTURERS, MER- CHANTS AND AGENTS. Wanted samples of various goods for the purpose of secur- ing orders from our Customers and Mer- chants Agency business undertaken on a small commission. General orders are executed to Rajas. Ladies and Gentlemen! Banker’s reference as security will be given if required. For full particulars and_trial orders please apply to us at once. K. M. Thakersey & Co., Ahmedabed, India. WANTED Reliable Men and Women to place EGGINE in stores and appoint sub- agents. Takes place of eggs in baking and cooking at less than 9c dozen. Morris- sey Company, 4403-19 Madison St., Chicago. EVERY HOUSEHOLD ON ARM— SMALL TOWN OR SUBURBS any lamps are used, needs and will buy ‘the wonderful Aladdin Mantle Lamp; bums common coal oil (Kerosene); gives @ five times as bright as electric. Aw Gold Medal at San Francisco Exposition, One farmer cleared over $500 in six weeks: hundreds with rigs earning $100 to $300 per month, No cash required. We capital to reliable men. Write quick fo wholesale prices, territory and sample for free trial, Address nearest office. Mantle ee J —F ag 3 Bldg., Chicago, ll. antle Lamp Co., Thermo ; York City. Bie AGENTS — STEADY INCOME. Large manufacturer of Handkerchiefs and Drew Goods, etc., wishes representative in each locality. Factory to consumer. Big profits, honest goods. Whole or spare time. Credit given. Send for particulars. Freeport Mfg. Co., 33 Main St., Brooklyn, N. Y. WHO was it said ‘‘Nobody re Classified Advertisements’’ ? ft—s 4 reading them? Hundreds of others an reading them, too—right now. Too bad your advertisement isn’t in this space. STAIBRITE GOLD LETTERS make the best window signs. [Easily applied. a gee | a ca free, Sta e Co., Dept. F, n, an " New York. . . = AGENTS: 5002, Profit, Free Sample Gold and Silver Sign Letters for store fronts and office windows. Anyone can put on. Big demand everywhere. Write today for liberal offer to agents. Metdllic Letter Co., 40 N. Clark St., Chicago, U. 8. A. MEN AND WOMEN earn up to $3,000 yearly distributing guaranteed hosiery from mill to wearer. All or part time. Re- eat orders insure permanent increasing usiness. No capital or experience needed. P ie Mills, 2733 North 12th &, “ee % $250 for reliable man or woman; dis- tribute 2,000 free packages borax powder with soaps, etc., in your town; no money or experienee needed. 8S. Ward Co., 214 Institute, Chicago. DOUBLE YOUR INCOME, Agents mag- azine shows how. ‘Two issues, 10c, Agents Magazine, Chicago. AGENTS—Make a big Clean-Up selling our Xmas. Specials. Quick sales. $25 to $75 weekly a cinch. Write for colored cir- culars and immediate appointment. E. M. Davis, President. K-51 Davis Bldg., Chi- cago, IIl. TWO of the greatest obstacles with which Classified Advertising has to contend are problem. BIG BUSINESS FOR AGENTS—New Clothes washing machine. Fits set or ordinary tubs. Sells for $10, with big per- centage profit. Won medal, Panama-Pacific Exposition. Just the thing for apartments. Write for proposition. Home Devices Corp., 223 Bush Terminal, Brooklyn, N. Y. AGENTS: Sell rich looking 36x68 im- ported rugs, $1.00 each; Carter, Tenn., sold 115 in 4 days, profit $57; you can do a. — a exclusive territory. ample post prepaid 98c. P. Condon, Importer, Stonington, Me. i When writing to Advertisers please mention Popular Science Monthly and World’s Advance. bates |IROSBSSez fo} om wee eee NH ier aeow Iced an on SS & sees, ae Ss _—-—_

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fecemnil anlg ESREEE BETER. #F | SAR281 s8¥e| Eedel“ZSPE gal 1 Basel PREPS Bl EF ( Ba5enFl £e POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 11 —— AGENTS AND SALESMEN WANTED HELP WANTED HELP WANTED exwemann Man per County: Strange in- Lang saries world—agents amazed. Ten yention sed men divide $40,000. .Kor- stad, a farmer, did 2,200 in 14 days. Schleicher, & minister, $195 first 12 hours. 1,200 cold cash, made, paid, banked by neman in 30 days; $15,000 to date. A or cold running water bath equipment for any home at only aay ane. waterworks if ~ planing clusive =, pg . Write letter or po - oy "hulen Mig. Co., 4193 Allen Bldg., Toledo, Ohio. ‘ AGENTS — SOMETHING § N’ EW—Fastest sellers and quickest repeaters on earth. Permanent, profitable business. Good for $50 to $75 a week. Address, American Pro- ducts one 3139 Third St., Cincinnati, O. SHARPENERS.” “PENCIL SELL ue “Frazee.”’ Box ample and terms, 25c. fe Kokomo, Ind. GOOD MONEY MADE AT HOME knit- ting hosiery. Machines furnished on time. We buy or sell your goods. Easy and con- stant work. WHEELER CO. (Inc.), Dept. 131, 337 Madison, Chicago. YOU CAN TURN YOUR SPARE TIME INTO DOLLARS by taking subscriptions from your friends and acquaintances. You, as a regular reader of ‘‘Popular Science Monthly,’” know its good points and can present its attractive features in a way which , will readily secure a large number of subscribers. Convince me that you are in earnest and willing to take advantage of this opportunity, and I will gladly send you full particulars as to how to go about the work, and also special appointment pa- pers for your territory. Don’t wait until your neighbor has secured the appoint- ment—write today. Circulation Director, Popular Science Monthly, 243 Fourth Ave- nue, New York. $25 WEEKLY collecting names and ad- dresses. Send stamp. Superba Co. 8, Baltimore, Md. , NO PULL REQUIRED to land a job ‘after reading the ‘‘Position Seeker’s Guide’ Price 25 cents per copy. Argyle Pub. Co. ‘San Diego, Cal. | BUSINESS OPPORTUNITIES FREE for Six Months—My special offer to introduce my magazine. “Investing for |Profit.”? It is worth $10 a copy to any one \who has been getting poorer while the rich richer. It demonstrates the REAL earning power of money, and shows how any one, no matter how poor, CAN acquire riches. “Investing for Profit’? is the only progres- }sive financial journal published. It shows j}how $100 grows to $2,200. Write NOW ,and T’ll send it six months free. H. L. Barber 423, 20 W. Jackson Blvd., Chicago. ——aTTAW THE 5 LLOW THE DOLLARS—$50 to $100 eng money yours; something new, Pot an old, wornout proposition; field un- touched; experience unnecessary; takes everybody by storm; money rolls in; show 50, sell 40; demonstrated in one minute; gells on demonstration. The new Inkless Fountain Pen, the twentieth century won- der; never leaks or spills; with this pen no more use for the ink bottle; sample pen 50c; this proposition is 18 karat; money back if not as represented; agent’s profit 200 per cent; exclusive territory; send for agency today. INKLESS FOUNTAIN PEN CO., 300 E. Hillside ave., Des Moines, Ta, U WANT A BETTER POSITION? oar opportunities limited, and are you dissatisfied with present conditions? Would you accept a real, live, responsible job which... enable you to broaden out and become something worth while? Em- ployers in every part of the country are on the lookout for high-grade, honest, intelli- gent and ambitious men. The demand has never been so great. Why not write an advertisement to the employers of the coun- try? You can reach them through the Classified Department of ‘‘Popular Science Monthly.” AGENTS—HERE’S THE BEST LINE of food flavors, perfumes, soaps, toilet prep- arations, etc., ever offered. No capital needed. Complete outfits furnished free to workers. Write today for full particulars. American Products Co., 3140 Third St., Cincinnati, O. I NEED branch managers for my world wide mail order business, operate from your own home in te time; no canvassing or dling; experience unnecessary; _ you peanid make $50 weekly. Butler 512 Fac- tories, Toledo, Ohio. WANTED—AGENTS; 150 PER CENT. PROFIT selling new easy wringer mop; every home buys; Martin sold 131 in two days; Randel sells 18 in 4 hours; Baker made $9 in 2 hours; one man’s orders, $2650 in one month; get details. U. 8S. MOP CO.,.326 Main St., Toledo, O. MAKE MONEY TODAY. MAKE DOL- LARS TOMORROW. Secure exclusive sales rights for Leswerk Laundry Tablets which repeat and repeat after introduction; sold to stores they yield permanent increasing income without personal canvass; guaran- teed satisfactory or cost refunded. Send 10c for whole month’s supply and Tried and Proved Sales Plan. LESWERK MAN- UFACTURING COMPANY, RICHMOND HILL, NEW YORK. HELP WANTED WANTED—Ambitious workmen; your work on actual jobs ays for teaching trade of automobiles, plumbing, bricklay- ing; only few month required; 700 stu- dents ast four years; write for informa- tion. Bruns Contracting Trade School, 234 Aliso, Los Angeles, Cal. WANTED—Reliable men for Real Estato, all parts of United States. No drones. Cornell Company, Great Barrington, Mass, BE A DETECTIVE—Earn $150 to $300 monthly. Easy work; we show you. Write Wagner, 1243 Lexington Ave., New York, Dept. 133. EARN $25.00 to $75.00 WEEKLY. “BE A TREE EXPERT.’’ Learn by mail. | oaoend free, Jno, B, Pitts, Wilmette, 25. WEEKLY earned at home making household specialty. Whole or spare time. No selling. Steady workers wanted in all districts. Write K. Dept. Sayres Co., Toledo, Ohio. BE A TRAFFIC INSPECTOR — WE TEACH YOU. A new profession. $4 a day to start. Unlimited opportunities for travel and advancement. Positions now open. _ Prep. School, Dept. Al, Buffalo, | ARTIFICIAL MARBLE instructions, \sanitary flooring, ornamental casting, con- jerete, plaster, papier-mache, interior dec- forations, garden furniture, statuary, life casting, elastic moulds, electro metalizing, particulars; 200 illustrations FREE, Mahler, {C-117 Russell St., Brooklyn, N. Y. WRITE Motion Picture Plays; $50 each. Correspondence course unnecessary. Detail — ow Publishing Co., 3066, Cincin- nati, Ohio. I WILL START YOU earning $4 daily at home, silvering mirrors; free instructive booklet. G. F. Redmond, Dept. H., Bos- ton, Mass. WANTED: Man in each territory to ad- vertise and place samples of new specialty with automobile owners; good pay; whole or part time; no common agency scheme. OROLO MANUFACTURING COMPANY, Louisville, Kentucky. WRITE Motion Picture Plays: $50 each. Correspondence course unnecessary. De- tails free. Atlas Publishing Co., 3065, Cin- cinnati, Ohio. | MAIL ORDER BUSINESS, We start you jright. Furnish everything. Ideal Novelty {Co., Desk 5, Palmyra, Pa. | WANT BIG PROFITS? Learn Tartaric Mirror Silvering; New Process. -Open enor- mously profitable business. Particulars free. C. Barstow, 514 23rd Street, Oakland, Cal. LET the Parcels Post help you. Add ($15 to $25 weekly) to your present salary or income. Start during spare time and build up a permanent mail order business of your own. We show you how and help you make good. No canvassing. Experience u ry. The Parcels Post makes success WANTED—Circular Distributors. Send 10c for application contract. (None free.) Oliver C. Barkley, Mount Pleasant, Penn- svivania. OUR NEW BOOK CATALOG containing titles and synopsis of hundreds of electri- cal, mechanical and scientific books will be sent free on request. Your name on a postal will do. Book Department, Popular —— Monthly, 245 Fourth Avenue, New ork, MEN to refinisixs lighting fixtures, brass beds, etc. All or spare time. or canvassing. Experience unnecessary. Write for particulars. Gunmetal Co., Dept. F., Decatur, Ill. THOUSANDS OF GOVERNMENT JOBS OPEN TO MEN, WOMEN. — $75 month. Short hours. Steady work. Common edu- cation sufficient, Write immediately for free list of positions now obtainable. Frank- lin Institute. Dept. D-50, Rochester, N. Y. EARN $10.00 to $20.00 Weekly Mailing Letters at home. Particulars and _ outfit 10c. Morriso, 2513 S. 2nd St., Philadel- phia, Pa. GOVERNMENT Civil Service Positions pay Big Money. Examinations everywhere soon. Get prepared by former Government Examiner. Booklet free. Write today. Paterson. Civil Service School, Box 3019, Rochester, N. Y. WANTED—Circular distributors. Send dime for full particulars; sample of Journal. A Barnes, Box 5A, Helena, Ark. BE A DETECTIVE—Earn $150 to $300 per month; travel over the world. Write Cc. T. Ludwig, 410 Westover Bldg., Kansas City, Mo. $10.00 WEEKLY; advertising proposition ; nothing to sell. Spare time. Advertising Agency, B762 Shepard, Ohio. IF YOU HAVE HESITATED to ‘try Classified Advertising for fear your lack of experience in writing advertisements might stand in the way of your success, you need delay no longer. Write a letter to the Classified Department of Popular Recience Monthly, 240 Fourth Avenue, New No capital’ doubly sure. Our new ideas and up-to-date plans bring the money. No so-called ‘‘Course of Instruction’ to sell. We give that free. Write to-day. Address Pease Mfg. Co., Inc., Dept. B, 70 Broadway, Buffalo, N. Y. WE pay 25c each for farmers’ names. Send dime for contract. ‘‘C-Sun,’”’ Leroy, Mich. I WANT TO SEND YOU PROOF OF THE WONDERFUL pulling power of the Classified Columns of this magazine. If you want to buy something, sell something or exchange something, write today for full particulars. D. Coutlee, Manager Classified Department, Popular. Science Monthly, 238 Fourth Avenue, New York. ) HOW TO OPERATE a mail order busi- ness. 30 big profit plans and year’s mail- ing service sent for 10c. Mail Dealers’ Wholesale House, 228 Franklin Bldg., Chi- cago. i_ $25,000 made with small Mail Order Business. Started with $3. Booklet free. Tells how. I’ll loan you $3. Al Scott, Cohoes, N. Y. ADVERTISERS, MAIL DEALERS. Our 1915 rate book lists 2,000 principal pub- lications, rates, circulation. Includes 30 mafl order plans. Price, 10c. Dearborn = Agency, 500 Franklin Bldg., Chicago, Til. | MANUFACTURERS, Promoters and Pat- ent Buyers are invited to write us stating the line of invention in which they are interested, as we can supply their wants in any class of patents. Victor J. Evans Co., 152 Ninth St., Washington, D. C. : I MADE $50,000 in five years with small mail order business; began with $5; send for free booklet; tells how. Heacock, Box 605, Lockport, N. Y. } START AN ADVERTISING AGENCY. Complete copyrighted instruction; also copy of secret to success in the mail order busi- ness. Price 40c postpaid. Money back if not satisfied. A. A, Barnes, Box 5A, Helena, Arkansas. ' WE START you in a real mail order business. Send 25 cents for samples of our own manufacture. . F. D. 4, Box 1914, Shaylor Mfg. Co., Portland, Me. York and state fully what you want to put into your advertisement and the amount of space you want it to occupy. Copy will be at once submitted for your approval, to- gether with full particulars as to rates, WE START YOU IN BUSINESS, furn- ishing everything; men and women, $30.00 to $200.00 weekly operating our ‘‘New Sys- tem Specialty Candy Factories’? home or small room anywhere; no canvassing. Op- classification and closing date of next avail- able issue. portunity lifetime; booklet free. H. RAGS- DALE Co., East Orange, N. J. . When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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12 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE a PATENTS AND PATENT ATTORNEYS PATENTS AND PATENT ATTORNEYS AUTOMOBILES AND ACCESSORIES” PATENTS—Trade-Marks. . Send for my free book, ‘‘How to Get Them.”’ It’s full of information you should know. Joshua R. H. Potts, 8 S. Dearborn St., Chicago; 929 Chestnut St., Philadelphia; 805 G St., Washington. PATENTS without fees. Free report and books. er, Washington, D. C. COMMERCIALIZE YOUR PATENTS, and get your income. We make it easy for you to interest capital or to exploit your invention yourself. Write for parti- culars. DECAMP & SLOAN MFG. Co., 420 Ogden St., Newark, N. J. PATENTS—Herbert Jenner, patent at- torney and mechanical expert, 606 F St., Washington, D. C. I report free of charge if a patent can be had and its exact cost. Send for circular. INVENTIONS WANTED—PATENTS PAY. I secure valuable patents and help make your invention a commercial success when patented. Send drawing or model for free report on patentability. Lester L. Sargent, G and 9th Sts., Washington, D. C. advance attorney’s Frank Full- PATENT FOR SALE—for household arti- cle. A. Sekulo, 1220 Allison Ave., Wash- ington, Pa. PATENTS SECURED THROUGH CREDIT SYSTEM. Free search. Send sketch. Book and advice FREE. Waters : Co., 4101 Warder Bldg., Washington, , ELECTRICAL OUR HANDY ELECTRIC LANTERN will light your way in garage, cellar, barn, closet; on the motor boat; in camp, or on the dark country road. Consists of japanned metal container, fibre disc with battery contacts, polished reflector, clear glass lens, miniature lamp and large non-detachable handle, making it possible for lantern to be carried on the arm. Simplest battery lan- tern made. Operated by ordinary dry bat- tery, which is slipped into metal container. Lantern stands 7% inches high, beautifully polished. Special prices while supply lasts, $1.25. Efficiency Company, 243 Fourth Avenue, New York. PATENTS OBTAINED THROUGH D. SWIFT are being sold to Large Manufac- turers. Write today for free books of ‘‘In- ventions needed,’’ and surpassing references. D. SWIFT, 371 Seventh St., Washington D. C., established in 1889. PATENT—Advice and Books free; highest references; best results. I procure patents that protect. Watson E. Coleman, Patent Lawyer, 622 F St., N. W., Washington, bD. C. WANTED New Ideas. Write for List of Inventions Wanted. $1,000,000 in prizes offered for inventions. Our Four Books sent, free upon request. Victor J. Evans & Co., 155 Ninth St., Washington, D. C. NO ATTORNEY fees until patent al- lowed. Send sketch for free report. Books free. Frank Fuller, Washington, D. C. I CANNOT AFFORD to give my services for nothing. Nelther can any other Patent ‘Lawyer. But I will, for a reasonable fee, secure the best patent protection obtainable for you. Try me. F. V. Winters, Regis- tered Attorney, 125 East 23rd St., New York City; also Washington. PATENTS and patentable ideas sold on commission. Best location and facilities. Fuller Co., 500 Fifth Ave., New York. PATENTS secured or fee returned. Send sketch for Free, search. test and most complete patent book ever published for free distribution. George P. Kimmel, At- ar 214 Barrister Building, -Washington, Cc. L. PARKER, Patent Attorney, 8 Mc- Gill Bldg., Washington, D. C. Inventors’ hand book, ‘Protecting, Exploiting and Relling Inventions’’ sent free upon request. IDEAS wanted—Manufacturers are writ- ing for patents procured through me. Three books with list 200 inventions wanted sent free. Advice free. I get patent or no fee. - e Owen, 44 Owen Bldg., Washington, * eal’? will tell you how. WHOLESALE prices on supplies and motors. Send for illustrated bargain sheet. Hyre Electric Co., 609 P-South Dearborn St., Chicago. RENEW old dry batteries at a cost of lc. each. Recipe sent for lic. Kalb Elec- tric Co., Maplewood, Mo. FOUNTAIN PEN FLASH LIGHT—the latest novelty and one of the most useful articles combined. May be carried in pock- et like ordinary fountain pen. Made of black metal; resembles rubber; contains miniature Mazda Lamp at one end; is oper- ated by small battery inserted in metal container. Light is operated by simply pressing steel clip which also fits over edge of pocket and prevents pen from falling out. May be carried in pocket with other pencils, etc, Is very useful on dark roads, in the garage, barn, closet or dark hall. Battery may be renewed at any time. Send for one today—only a few left. Complete with battery, Price $1.00. Efficiency Com- pany. 243 Fourth Avenue, New York. RENEW DRY BATTERIES. 3 guaran- teed processes, 10c. ‘‘IDEAL,’”’ 3315-PE., Belleplaine, Chicagé. DO YOU WANT TO KNOW how to make dynamos, motors, electric heating ap- Pparatus, wireless instruments and hundreds of other pieces of’ electrical apparatus? Our book ‘‘How to Make Things Electri- It is a valuable workshop manual for the student or ex- perimenter. Contains 200 pages, 184 illus- trations and clear, concise directions. Price $1.50 postpaid. Book Department, Popular —- Monthly, 245 Fourth Avenue, New ork. AUTOMOBILE OWNERS, ten list, Washington and Oregons ap emt 25,000 names $30; special list’ of Fries, both States, over 8,000 names, gis, ris Dunlap, 181 Twelfth, Portland, Gre, & GENERATORS, Batteries, Vuloanine Compressors, Engines, Lathes, Die tne, Effel_ Dynamo Works, Chicago, ° Cheap, SHOP Vulcanizer. Bargain. eS at cu prices. Vanderpools, Springtielg. "Onin s I_ WANT TO SEND YOU PROOF @ THE WONDERFUL pulling a... ’ OF Classified Columns of this magazine. & you want to buy something, sell something or exchange something, write to day ¢ full particulars. D.-W. Coutlee, =f ger Classified Department, Popular Scien, Monthly, 238 Fourth Avenue, New York” MOTORCYCLES, BICYCLES & SUPPLits CONVERT your bicycle into a revels * — yy BR Ly “aw Mone At- achment. atalog free. ha Dept. 68, Galesburg, Kans. = a SUPPLIES—Write for big catalog with prices lower than you now 4 Hammondsport, N. Y. pay. Mew, MODELS AND MODEL SUPPLIES THE L. E. B. POCKET TOO A handy tool for any possible aaa that may arise. Most practical, complete, convenient and best pocket tool-kit ever de vised. Is only 4% inches long and can carried at all times; 37 practical tools of finest steel; useful in the home, garage, at the bench, the office or factory, and on the road. Just the thing for the bicycle or motorcycle. Send for yours today, Price $1.00. Efficiency Company, 243 Fourth Avenue, New York. DRAWINGS AND MODELS FOR IN- VENTORS: Designing and perfecting ori- ginal ideas into commercially practical form. Expert mechanical knowledge, ex- ceptional machine facilities and strictly honorable and confidential dealings place our service in a special class. Correspond- ew invited. ELECTRIC SHOP, Beatrice ebr. MODELS made for inventor; general ma- chine work; designing and perfecting; de- veloping automatic devices and machinery; in a position to do all kinds of light tool and machine work; prices reasonable; esti- mates cheerfully given. Ideal Machine Works, 61 Ann St., New York City. MODELS, dies and manufacturing for inventors by builders of ‘Tools That Work.”’ La Croix Tool Co., 214 N. 2ist St., St. Louis, Mo. MOTORS, ENGINES AND MACHINERY TOY TRANSFORMERS while they last, $1.60; also a few Bell ringing transformers, 1.10. A. . Darling, 1532 N. Capitol Avenue, Indianapolis, Ind. ALTERNATING CURRENT, REBUILT motors. Reliable makes only. General Electric, Fort Wayne, Emersorn,”* Wagner, Westingh ¥y% H.P., $13.00; 1/6 ELP., FOR PRACTICAL WORKERS DON’T LOSE YOUR RIGHTS to pat- ent protection. Before proceeding further send for our blank form, Evidence of Con- ception, to be signed and witnessed. Book, suggestions and advice free. Lancaster cong —— 232 Ouray Building, Washing- on, a SEND FOR FREE BOOKLET. All About Patents and Their Cost. Shepherd Campbell, Patent Attorneys. 500 B Victor Bldg., Washington, D. C. PATENT WHAT YOU INVENT. It may be valuable. Write me. No attorney’s fee until patent is allowed. Estab. 1882. “‘Inventor’s Guide’ FREE. Franklin H. Hough, 541 Loan & Trust Bldg., Wash- ington, D. C. “PATENTS AND PATENT POSSIBIL- ITIES”’ is a 72-page treatise which tells all about patents, what to invent and where to sell it; it gives honest advice to in- ventors, and is full of valuable and in- teresting information; write for it today! t is FREE. H. 8. Hill, 929 McLachlen Building, Washington, D. C. HOW TO MAKE YOUR Own Movies, Wireless Telephone, Model Submarine; also score of practical kinks for amateur mechan- ics and motorists, all in new 96 page book sent for 5c stamps. We want you to know us. Technical Press Association, Aeolian Hall, New York. CHRISTMAS SUGGESTIONS WHAT COULD BE MORE acceptable as a Christmas gift than @ good book? Such a present is always gratefully received, and not only does it please the recipient on account of its usefulnes, but it serves as a constant reminder of an existing friendship. We carry a complete line of electrical, mechanical and _ scientific books—the kind that appeal to the amateur as well as the specialist. Send for our catalog today and make your selection. A post card will do. Popular Science Monthly, 241 Fourth Avenue, New York. APPARATUS EXCHANGE THE PATENTOME is free; an educa- tion in obtaining patents; established 1865 Anderson & Son, Attorneys, 712 Seventh St., Washington, D. C. AUDION PANEL SET, % KW trans- former, rotary, condenser and other ap- Pparatus all new. Want typewriter or what have you? Chas. Service, Bala. Pa. $15.00; % H.P., $18.00. Direct current bargains. Satisfaction guaranteed or money refunded. Write for illustrated list sup- plies and motors. Hyre Electric Co., 609A- Sourth Dearborn St., Chicago. STORAGE SALE: Small motors and All new, 110-volts,.% H. P. %H. P. A. C. $18.50; % . P. D. C. $6.50; & light Dynamos, $12.00. Motor Generator Sets, $35.00. Other sizes, all voltages, less than half price. Johnston, West End, Pittsburgh, Pa. PRINTING AND ENGRAVING GOOD Printing at low prices; 1,000 good letter heads, envelones, cards, _billheads, labels, circulars, $2.50; samples free; cata- logues, booklets and circulars our specialty. Ernest L. Fantus Co., 523 8. Dearborn 8t., Chicago, 250 BOND LETTERHEADS, white or W. Kinnear, Box 206, Brooklyn, N. 50 CARDS, Name, Address (Business), 20c. Prompt, Stylish. Will please. Royal Print, Mount Carmel, Pa. FIREARMS WANTED FIREARMS—Old-Time and Modern. Buy, sell, exchange all sorts. Stephen Van Rensselaer, 49 Front St., New York City. When writing to Advertisers please mention Popular Science Monthly and World’s Advance. colored, printed, $1.00, pestpatd. Samples. -

Page 173

' SBI PSSial seFenFSl &l sH#l PrSerr tf 371 S8Sée2asheagnl ical 1 #a] PSeral a>

POPULAR SCIENCE MONTHLY AN- WORLD’S ADVANC# 13

ee

STAMPS AND RARE COINS WIRELESS

Free; 52 different for- FOREIGN fe China and Venezuela, | go apply for our high grade approval Oe ent. Send two cent stamp for return ot Edgewood: Stamp Co., Dept. M., Priford, Conn. ~ IFFERENT STAMPS from olneten. 12c, Edward Lufbery, Walling- ford, Conn. AMP 2 different from warring na- B a) different foreign coins, 15c.; 20 Belgian stamps, 10c. Lists free. To- ledo Stamp Co., Toledo, O AMPS FREE—5 different Nyassa (gir- de bay or 5. different Japanese china. or 1916 Hungarian War Stamp, big rico lists, bargain lists, $2 premium Fupon. etc., free for 2c postage. W. C. Phillips & Co., Glastonbury, Conn. ELL OR TRADE YOUR VALUABLE COINS ol STAMPS through _ these columns, See top of first page, this sec- on for rate and closing date of next

WOULD YOU LIKE to know “How to Make Wireless Instruments?’’ This book will give you just the information you need. It is a treatise for the experimenter and amateur on the construction of wireless instruments and apparatus; contains 94 pages, 30 different instruments and 80 il- lustrations. Price 25 cents, postpaid. Book Department, Popular Science Monthly, 245 Fourth Avenue, New York. $10 COMMERCIAL KEY FOR $4. Money refunded if not satisfied. Massie Wireless Telegraph Company, Room 314, Nationai Building, Providence, R. I. “WIRELESS HOOK-UPS,” containing 96 pages, 165 different ‘‘hook-ups’’ and 171 illustrations, is a book which every ex- perimenter should have in his collection. This book contains a full set of diagrams fully illustrating every possible wireless connection. It will enable you to get ex- cellent results. Sent postpaid for 25 cents, Book Department, Popular Science Month- ly, 245 Fourth Avenue, New York.

available issue.

NOTES, STAMPS, Indian Rel- Bias <i Fi ten Weapons exchanged for United Profit Sharing Coupons. _ Booklet for Stamp. Coin Exchange, New Rochelle, N. Y.

Coins Bought and Sold. Fall ome list of colns for sale, free to collectors only. Bfying catalogue quoting prices I pay for coins, cents. Wm. Hesslein, 101 Tremont _St., Boston, Mass. $600 paid for hundreds of old ake dated Bom 1895. Send 10 cents at once for new illustrated coin value book, size 4x7. It may mean your fortune. Clarke & Co., Ccin Dealers, Box 76, Le Roy, N. Y.

AMPS FREE. Choose one. 100 dif- sanat Seed States, 50 Sweden, 50 Norway- 901 foreign, 50 Italy, 50 Asiatic, by remitting 25c, six months subscription. Makeel’s Stamp Weekly, Boston, Mass. 100 (all different) free; post- P . nomen paper. Quaker Stamp Co., Toledo, Ohio. OLD STAMPS WANTED FOR CASH. We buy rare or old stamps of any coun- try, also old or large stamp collections, old letter files (from 1843 to 1870) of private individuals or old business or banking firms. PREMIUM LIST 10c._ Address, C. E. HUSSMAN STAMP CO., Dept. L.L., St. Louis, Mo. GAMES AND ENTERTAINMENTS

PLAYS, Vaudeville Sketches, Monologues, Dialogues, Speakers, Minstrel Material, Jokes, Recitations, Tableaux, Drills, Enter- ments. Make-Up Goods. Large Cata- log Free. T. S. Denison & Co., Dept. 26, Chicago.

LEARN to hypnotize and make fun and money. Send for free book to M. D. Betts, Sta. 129, Jackson, Mich. MAGIC POCKET TRICK FREE. Worth 25c. Illustrated Catalog included. Send 6c stamps. Magic Co., Sta. 17, 249 West 38 St., New York. “MAGICAL — ENTERTAINING.” Free Course (10 Lessons) to introduce 50 only. Magical Outfit, 50c. Part, 25c. Sample Trick, 10c. Herrmann ‘‘Magicschool,’’ 407 Lexington Ave., New York. 360 POPULAR TOASTS—Selection suit- able for all occasions, 10c. Wedge Mfg. Co., “L.” Binghamton, N. Y. MISCELLANEOUS INDIAN CURIOS, Stone Age Specimens. Antique Guns, Pistols and Daggers from all parts of the world. Illustrated list, 6c. N. Carter, Elkhorn, Wisconsin. gaps DUATED CIRCUMFERENCE TRIP, Figuring abolished; 25c. C. Reeves, Darien Center, New York. GUMMED LABELS—ADVERTISING STICKERS

GUMMED LABELS, 1,000, 60 cents; 40 Pp. catalogue, 2 cents. MacTaggart, 1235 Arch Street, Philadelphia, Pa.

FOR SALE: Transmitting set, cheap. Geo. Barnes, Stanbridge East, Quebec.

EVERY WIRELESS OPERATOR AND EXPERIMENTER should have a copy of the Fourth Annual Official Wireless Blue Book of the Wireless Association of America. Contains a list of the Radio Stations of the United States, including merchant ves- sels, revenue cutters, vessels of the U. S. Navy, U. S. Amateur Stations and map of the United States showing locations of Government and Commercial Stations. Sent postpaid for 15 cents. Book Department, Popular Science Monthly, 245 Fourth Ave- nue, New York,

TELEGRAPHY

TELEGRAPHY—Morse and Wirelese— Also Station Agency taught. R. R. and Western Union Wires and complete Mar- coni Wireless Station in school. Graduates assisted. Marconi Co. employs our wire- less graduates. Low living expenses—easily earned. Largest school—established 40 years. Investment, $25,000.00. Correspond- ence courses also. Catalog Free. Dodge’s Institute, 16th St., Valparaiso, Ind.

LEARN TELEGRAPHY at HOME in half usual time. Trifling cost. Omnigraph Auto- matic Transmitter sends you railroad or wireless messages at any speed, just as ex- pert operator would. Morse and Continental codes. Adopted by U. S. Govt. Catalog free. Omnigraph Co., 394 Cortlandt St.,

AERONAUTICS

BOYS—Would you like to build a Bleriot Monoplane? We can furnish you with an exact model of this wonderful machine, with complete directions and large blueprint, all ready to put together. It’s great fun building this model and greater fun flying it after it has been completed. Send for one today—only a few left. Price $1.00 complete. Efficiency Company, 243 Fourth Avenue, New York,

BUILD A FLYING MACHINE—It’s great fun building the Percy Pierce Flyer. We furnish you complete model, all ready to put together, with full directions and large scale drawing. This model is an exact reproduction of Mr. Percy Pierce’s famous prize winner. It is very easy to assemble the parts if you follow the direc- tions enclosed, and then comes the real fun. Better send for yours today—while the supply lasts. Price $1.00 complete. Efficiency Company, 243 Fourth Avenue, New York.

FOR SALE OR TRADE

TRADE—Indian twin for 3 KW, 110 or ~ Vv. D. C. generator. Ralph Leffler, Tif- An, Ohio.

TYPE AND PRINTING material at bargain prices. Now is the time to buy. All sizes rebuilt, Job Presses, very cheap. Catalogue free. Philadelphia Printers Sup- ply Co., 14 So. Fifth St., Philadelphia. CAMERAS, PHOTOGRAPHY AND SUPPLIES

HAVE you a camera? Write for sam- ples of my magazines, American Photog- raphy and Popular Photography, which tell you how to make better pictures and earn

money. F. R. Fraprie, 147 Pope Bldg., Boston. KODAKS, Graflex, Cameras, Lenses— Everything photographic; get bargain list; you can save money by sending your order to Willoughby, Broadway and llth S&t., New York. AMATEDR Photographer’s Weekly, $1.00 yearly, weekly competitions, criticisms, il- lustrated, for beginners. Three months’ sub- scription 25c. Amateur Photographer’s Weekly, Cleveland, O. SEND 10c with spool of film and let me show you my quality Kodak Finishing. Slocum, 406 Main, Peoria, Ill. . INSTRUCTIONS AND FORMULAS for phosphorescent photos, disappearing photos, photos on apples, cloth, chinaware, etc. Simple enlarger, trick pictures—25 in all for 25c. Disappearing photo free with each order. Money back basis. A. E. Benson, Stewartville, Minn.

AMATEURS with focussing cameras learn new plateless process worked without special apparatus or material. Stamp brings photo and __ particulars. Koch’s Gallery, La Madera, New Mexico. BEAUTIFUL CHRISTMAS KODAK en- largements for gifts, 8xl0 mounted 25c. Send only the negative. KODAK FINISH- ING, 50c offer for 10c. Send 10c. (stamps), and roll of film, any size, 6 or 12 exposure; will develop film and send you 6 pictures from best negatives. Mention this ad. Roanoke Cycle Company, Roanoke, Va.

PICTURES, POSTCARDS and PENNANTS

FASCINATING PICTURES: 28 Artistic beauty poses, 10c; catalogue 2c. Taylor Brothers, X-2130 Clifton Avenue, Chicago. ART STUDIES Taken from Life for Art Lovers. Samples 10 cents. W. Girard, Box 29, Dept. F., Holyoke, Mass. ART STUDIES—Photographs from mod- els. War views. Finest collection for artists and art lovers. Illustrated catalogue — Kilary, 103 Avenue de Villiers, Paris, ‘rance,

OPTICAL GOODS WE BUY, sell and exchange bargains in microscopes, telescopes, binoculars, cameras, etc.; bargain list sent. Kahn & Son, Op- ticians, No. 54 John St., New York. Es- tablished 63 years.

FORMULAS 10,000 RECIPES, Formulas, etc., in our “Twentieth Century Book of Recipes, Formulas and Processes.” For $3.00 it gives you information that represents the collection of years and the expenditure of thousands of dollars. Covers everything from the making of simple glues and ad- hesives to the tanning of leather, the mak- ing of photographic materials, working of metals, etc. Book Dept., Popular Science MONTHLY, 245 Fourth Avenue, New York. 100 MONEY MAKING FORMULAS, 10c. Process Company, 417 Ft.-Dearborn Bldg., Chicago. MILLION VOLTS THROUGH BODY. Make money on stage. My big new book tells you how. Send $2.00 on moneyback guarantee. T. S. Curtis, Aeolian Hall, New York.

150 FORMULAS and catalog = 1c. “IDEAL,” 3311-PE. Belleplaine, Chicago.

RAZORS AND DULL RAZOR BLADES A HIGH GRADE GUARANTEED Bar- ber’s style razor for $1.50. Your money back if not satisfied. R. R. Wiese, Atlantic, Towa. ‘ GRIND, hone any blade, 2c. Keenedge Oshkosh, Wis.

When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

Page 174

14 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

MOTION PICTURE PLAYS EDUCATIONAL AND INSTRUCTION BOOKS AND PERIODICALS

WRITE MOVING PICTURE PLAYS: $50 each. Correspondence course unneces- sary. Details free. Atlas Publishing Co., 306, Cincinnati. WRITE PHOTOPLAYS; $50 each. Ex- perience unnecessary; details free to be- ginners. Producers’ League 194, St. Louis. FREE—Our book HOW TO WRITE PHOTOPLAYS. Enterprise Co., W. 3348 Lowe Ave., Chicago, Ill. WANTED! Your ideas for photopiays and stories! Big Rewards! Experience un- necessary. We CRITICISE FREE. Sell on commission. Hundreds making money. Get busy! Write Today for details! Story Revision Co., 200 Main, Auburn, N a WRITE MOVING PICTURE PLAYS— Big prices paid. Try it; we'll help you. Details free. Giese Co., 225. Whiteman, Cincinnati, Ohio.

MOTION PICTURE BUSINESS MAKE $25 TO $50 per night. We start you into the Moving Picture Business on the installment plan with complete out- fit. No experience necessary. Write for free catalogue. National Moving Picture Co., 1012 Ellsworth Bldg., Chicago. TYPEWRITERS AND SUPPLIES GOOD. SERVICEABLE typewriters, $7.50 and up. Postcard brings list. First class ribbon, any machine, 25c. Hub Type- writer Co., 286 Devonshire St.. Boston. TYPEWRITERS, all makes, factory-re- built by famous ‘‘Young Process.”” Look like new, wear like new, guaranteed like new. Our big business insures ‘Square Deal’” and permits lowest: cash prices—$10 and up. Also, machines rented—or sold , on time. No matter what your needs are, we can best serve you. Write and see— now. Young Typewriter Company, Dept. 402, Chicago, Ill. ORGANIZING COMPANIES NEVADA INCORPORATIONS OPER- ATE EVERYWHERE. Save expenses. Most convenient popular standard charters. Forms—information—free. CORPORATION CHARTER TRUST COMPANY (WA), Reno, Nevada. FOREIGN INVESTMENTS

DETROIT TECHNICAL INSTITUTE Offers courses of university grade in Auto- mobile, Chemical, Electrical and Mechani- cal Engineering, Law, Accountancy, Busi- ness Administration, Pharmacy, Salesman- ship, Advertising, Real Estate, Credits and Watchmaking. Bulletin sent free. Address Director of Education, Room 310, Y. C. A., Detroit, Mich. LEARN MECHANICAL DRAFTING. Complete courses. Personal _ instruction until position is secured, also short courses for shop men. Detroit School of Drafting, 277 Woodward Ave., Detroit, Mich. ~- THE ARGASCOPE TRIANGLE solves geometry, ‘trigonometry, mechanical drawing and plotting problems. New features, fifty cents postpaid. ARCASCOPE SALES CoO., Mifflinville, Pa. ELECTRO METALIZING art casts, particulars; 200 illustrations FREE. Mah- ler, J-117 Russell St., Brooklyn, N. Y. ARE YOU AMBITIOUS? Individualized Efficiency is a course of proper direction and correction, adapted to supply the es- sentials of health, inspiration, and success. Simple, yet exceptionally effective. Parti- culars cheerfully furnished. Price very low. Ephraim Buchwald, Dept. X, 113 East 129 St., New York.

ALS MAKE ART CRAFT ELE This book will show you home splendid series of designs with complete dip endid for building the different type lam ut are used in a home from the hall ahr the complete chandelier. These lam ~ very attractive, employing wood pe me and metal in their makeup; " still & construction is so simple as to’ require their ordinary tools and workmanship, «, ~~ Make Art Craft Electric Lamps” aj Pe tains directions for working copper 2"; brass with a design for a hammered . table lamp. Price, 25 cents Dostpai Book Department, Popular Science Mo 4 245 Fourth Avenue, New York. —, WONDER book on Hypnotism, personal magnetism, magnetic healing and ma — — = eng | one. Send your - ress today. M. D. Betts, Sta, . son Afi, S, Sta. 129, Jack. NEW BOOK CATALOG titles and synopsis of hundreds ot cen cal, mechanical and scientific books will be sent free on request. Your name on postal will do. Book Department, Populat Science Monthly, 245 Fourth ci York. Avenue, ‘Nes

LEARN Harmonica (mouth-organ). o plete self-instrucor, 15c. G. El r "3 Mich, ~~ Oe

MOULDS, Models, Novelties, Statuary, Architectural work and designs for Educa- tional Institutions. Reproducing the high- est rk of art the world contains. Can be duced by any member of the family. Free Particulars. Roth, F. 45 Frost St., Brooklyn, N. Y. NEWS CORRESPONDENTS

WRITE for newspapers and magazines. Big Pay. Experience unnecessary; details = Press Reporting Syndicate, 400 St. uis.

MUSIC AND SHEET MUSIC EXPERIMENTERS: Have read the new edition of ‘‘Construction Or Induction Coils and Transformers’’ by Thomas Stan- ley Curtis? It’s the biggest 25 cents’ worth in the field of electrical literature. Tells how to design and build magnetic 1 transformers, high frequency apparatus low voltage transformers, induction coils, con. densers, gaps, etc., and gives dozens of valuable hints. Send for your copy today Book Department, Popular Science Monthly, 245 Fourth Avenue, New York. , SEX EDUCATION. Send 10c for “ When and How to Teach Your Child Pa sonal Purity.’’ Valuable for parents, teachers and students. Book Specialists, 975 McClurg Bldg., Chicago.

SONG POEMS WANTED—For publica- tion. Past experience unnecessary. Our proposition positively unequalled. Send us your song poems or melodies today or write for instructive booklet—it’s free. Marks- Goldsmith Co., Dept. 21, Washington, D. C,

SHORT STORIES—POEMS

CAPITAL introduced for sound enter- prises of all kinds, 5 per cent commission; bond and stock issues placed; underwriting procured; references exchanged. Address ——. Byrne, Harcourt Street, Dublin, relan <4 CORPORATION CHARTERS, ETC. CORPORATION SERVICE SYSTEM (WA), Clarksburg, West Virginia, Incor- porates, organizes, represents companies, provides resident agents, offices, expert cor- poration lawyers through America; certifi- cates, seals, supplies. Saves expense. In- formation gladly furnished. REAL ESTATE—FARM LANDS IS HE CRAZY? The owner of a planta- tion in Mississippi is giving away a few five-acre tracts. The only condition is that figs be planted. The owner wants enough figs raised to supply a Canning Factory. You can secure five acres and an interest in the Factory by writing Eubank Farms Company, 934 Keystone, Pittsburgh, Pa. They will plant and care for your trees for $6 per month. Your profit. should be $1,000 per year. Some think this man is_ crazy for giving away such valuable land, but there may be method in his madness. I WANT TO SEND YOU PROOF OF THE WONDERFUL pulling power of the Classified Columns of this magazine. If you want to buy something, sell something, or exchange something, write to-day for full particulars. D. W. Coutlee, Manager Classified Department, Popular Science Monthly, 238 Fourth Avenue, New York.

EIGHTEEN WAYS TO MAKE MONEY. Interesting, isn’t it?- If you are mechani- cally or electrically inclined don’t fail to write for our free book. Your name on a postcard will do. Popular Science Monthly, 245 Fourth Ave., New York. SHORT STORIES, POEMS, photo plays wanted by 100 companies. No correspond- ence course. Details free. Gordon, Pub- lisher, 106, Cincinnati.

WANTED—Short Stories, Articles, Poems for new magazine. We pay on acceptance. Send prepaid with return, postage if un- available. Handwritten Mss. acceptable. Cosmos Magazine, 49 Stewart Bldg., Wash- ington, D. C.

FOR WOMEN

FREE to any woman. Beautiful 42-piece Dinner Set for distributing only 3 dozen cakes of Complexion Soap Free. No money or experience needed. S. Tyrrell Ward, 214 Institute Place, Chicago.

ADVERTISING

ADVERTISING DOESN’T PAY—when you do not advertise. Why don’t you grasp the opportunities that are offered by the Classified Department of ‘‘Popular Science Monthly and World’s Advance’’? Hundreds of advertisers use this depart- ment month after month to build up their business and increase their sales. You can insert a small advertisement in our Classi- fied Columns at the low rate of 10 cents Per Word. By so doing you will be placing your offer before hundreds of men and women in every part of the country who are, perhaps, searching those columns for just the article that you have for sale. Whether you want to buy something, sell something or exchange something; whether you want employment or employees, you can use to advantage the Classified De- partment of this magazine. We will be glad to give you further information on the subject—may we? Popular Science Month- ly, 241 Fourth Avenue, New York. EIGHTEEN WAYS TO MAKE MONKRY. Interesting, isn’t it? If you are mechani- cally or electrically inclined don’t fail to write for our free book. Your name on 4 posteard will do. Popular Science Monthly, 245 Fourth Avenue, New York,

NEW WIRELESS BOOK. Every amateur needs a copy of ‘‘How to Make a Wireless Receiving Set for Time Signals.” Tells in simple language and many pictures how to make and set up a perfect equipment, using only ordinary tools and ma , and without previous knowledge of electricity. Enclose 25c in coin and get this book by return mail. C. Brandes Inc., Room 813, 32 Union Square, New York.

CORRESPONDENCE COURSES, Techni- cal Books, Bought-Sold. Cut Rates. Cata- logue Free. C. Bubb, Detroit, Michigan,

SELL OR TRADE your tnused books through these columns. See top of fint page, this section, for rate and closing date of next available issue.

PERSONAL

YOGHURT conquers nine-tenths of all maladies by destroying intestinal self poisoning, caused by harmful bacilli; pat — Yoghurt Co., ) Bellingham, Wash,

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Tae OM Nao aee mee FE o oe - * erat ser ew te ee eI Bees reat MF Be Oe we SE Se wea a CU — POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 2 WEBSTERS DICTIONARY The Merriam Webster This new creation combines many gifts in one. Its contents is a wonderfully com- storehouse of accurate information of constant education and enjoyment to all members of the home, school, or office, The clear printing and beautiful a bindings are lasting examples ar Am the bookbinder’s art. 3 This gift will be treasured, ad- a mired, and used long after the —e holiday season has passed. A daily reminder of the giver. ‘SALIENT FEATURES: | 400,000 Vocabulary Terms. f 30, 000 Geographical Subjects. ; .; 12,000 Biographical Entries. Ls Thousands of other References, Hundreds of NEW Words not given in any other dictionary. 6,000 Illustrations. 2,700 Pages. The only dictionary with the new ided page, characterized ‘‘A SU UHH CNNNNNATNET ANNA PeRD SS Freee EEEGRECESE SS, ge NEW INTERNATIONAL te Only Grand oy et (Highest pe given to Dictionaries at -, of Genius. matter the Panama-Pacific Exposition was granted imens of the New = is equivalent to ae 15-vol- to the New International for super- sf “ght egular and Indie = ume encyclopedia. iority of Educational Merit. a, Papers, ote. ’ WRITE for specimen pages of both Regular and India-Paper Editions. o Name ONO soirecitoiigcisectesctscins G. & C. MERRIAM COMPANY, Springfield, Mass., U. S. A. LAC CATA a sg 0 ees "Hors the est Sift cto Oxlect” ee mate wlll | yy 4 at Please send me : FREE tape if you mention > 5 ry demand evervwhere for draftsm ——- from $125 to }- Ly ly. 1% wil pe ll personally instruct _—— to become a com- draftsman—I am an e ) a and quickly a Tiliy-enpert ecessary, while you in spare time. “ 1 Free Outfit Caplets 57. Drafting Write for Free. Book * Your nameand “Tie Rend to Boccsae™ al ilsend your bis free book Chief Engineer, Chicago Eng. Works, 455 Cass St., Dept. 4¥ Chicago, TIL DRAWING Learn by mail inyourown home. Cartooning, News- A paper, Magazine and Commercial Illustrating, also iw Water-Color and Oil Painting Drawing or Painting for profit and pleasure. We can develop your talent, This school has taught thousands. Free Scholarship Award- -special limited offer. Your name and address brings you full explanation and our -handsome illustrated Art Annual by return mail. Don’t delay. Write today. FINE ARTS INSTITUTE, Studio 179 Omaha, Neb. T'll teach you Dersonally by earn NT Ce [eat PSs SHOW CARDS a * mail. 16 years’ success- ful teaching. Biz field for men and women. You can EARN $18.00 to $45.00 A WEEK Schwartz (Del) writes us, “‘Yours is the only school that really teaches.’ nd for details. ETROIT SCHOOL a3 LETTERING Chas. J Detroit, Mich. HOFFMAN'S PAT’D DRAWING BOARD BRACKET FOR Artists, Illustrators, Designers & Draftsmen Attachtotableordesk. Adjustany height, to draw standing or sitting. Adjust any e angle. The board revolves. A strictly SN first-class article. Neat, Strong, Firm, Dur- A Sa able. Made of steel and iron, handsomely finished. waneoetie.: willsu: upporta board i 30” square. 30 days free tri Write for booklet No.10. A. HOFFM | AN & CO. 51 Kenwood Ave. Rochester, N. ¥. When writing to Advertisers please mention ‘Popular Science Monthly and World’s —

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16 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

Electricity! 6655 I'll Pay You $175 to $300 93 That’s what man Per Month superintendents a ay managers have said to OUR GRADUATES. That’s what one will say to YOU. It’s not out of the ordinary. In fact it is just what can happen if you become a COYNE trained man. It means success for you for life. Any mart between the ages of 15 and50 who has ambition,no matter how little education, can learn this big paying trade in g Our schools in a short time and at small expense. COYNE NATIONAL TRADE SCHOOLS argest and best equipped trades schools in Ame For 15 years we have sent hundreds of men out annually as skilled mechanics to help supply a idly increas- ing demand. Let ustrain yon for one of these big jobs. Our employment bureau places graduates into big paying positions free of charge. Men Wanted For These Trades Electricity. Plumbing | Bricklaying Motion Pic. Opr. Our Own Building Mech. Drafting We teach all these big paying trades under actual working conditions. We ion not have classes, do not use books, do not teach by oy repos ome Each man is instructed individuall ly er ht in — bi; shops. Drafting, Estimating and Plan ing included IN ALL courses. Wecharge a small tuition fee which can be made in easy payments if desired. All tools, equipment and material is furnished by the school FREE. Our institu- tion is open Day and Evening. Many of our students earn a part or all of their expenses while attending.

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AY 81010) <5 High Frequency Apparatus Its Construction and Practical Application By Thomas Stanley Curtis Price $2.00 postpaid This new book tells you all about Electricity in Stagecraft, Electricity in Horticulture, ete, and shows you how to make and use the apparatus for these experiments. FREE TECHNICAL ADVICE When you order an electrical or a mecha book, do you always get just the treatment of i subject that you desire? We maintain a De. partment of Technical Advice to aid you in the selection of the right book for a given purpose, [The service is free; will you tell us what sube jects interest you and let us help you to select. a. library—one book at a time if you wish? A stamp brings our literature promptly TECHNICAL PRESS ASSOCIATION 836-B AEOLIAN HALL, NEW YORK

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 17 Young Man! Your greatest opportunity To the man who wants to improve his condition in life—to increase his earning capacity—to get away from the monotony, grind and low wages of ordinary occupations—to elevate his social standing. the new profess- ion of Tree Surgery, which is not over-crowded, offers the young man of to-day his greatest opportunity . The Extension Course given by The Davey Institute of Tree Surgery will fit you to practice this profit- able profession. Learn TREE SURGERY and FRUIT GROWING By Mail You can become proficient in this work without interfering with your present occupation. An hour or so a day will give you a train- ing that will make your future bright and rrosperous. The work of a Tree Surgeon is healthful, fascinating and remun- erative. The call for men in this profession is far greater than the supply, and the demand is grow- ing. There are positions open at good salary and opportunities everywhere to establish a paying business of your own—Why work for others at small pay when you can be your own boss? Write to- day for our book “Ad Success.” ventures In Read what others have done, and learn how easily and quickly you can improve your wm condition in life. Wa THE DAVEY INSTITUTE OF REE SURGERY 374 Oak P ia Kent, Ohio Study Wireless Telegraphy in a $7,000 laboratory and in a licensed school with expert instructors. One of the largest schools with the smallest fee _in the country, endorsed by the Marconi Company engineers. $35 for 9 months. Scholarships given. New courses every month. Rate, $7 per month. Rooms for students in up-to-date Y. M. C. A. Y.M.C.A. Telegraph School 143 East 86th Street New York, N. Y. DO YOU LIKE TO DRAW? Cartoonists are well pald We will not give you any grand prize if you answer this ad. Nor will we claim to make you rich in a week. But if you are anxious to develop your talent with a successful cartoonist, so you can make money, send a copy of this picture, with 6 cents in stamps for portfolio of cartoons and sample lesson plate, and let us explain, TheW.L. EVANS SCHOOL OF CARTOONING 825 Leader Bidg., Cleveland, Ohio want MORE ; MONEY 7 ? WANT . Branch eam agen the art art of Sign & Showcard W Writin; + Sones stone ein Cone hl eake peu ssou. $6.00 Per Day or M is the union need - Fr pemer other towns. You ek. Have ve a big business of f} can make even your cor: We Fae booklet ‘ree seh Plaine every~ SCHOOL OF Oe TTERING & DESIGN se iingi sons oF Chicago. tMinois OSCAR A.FORS PRINCIPAL Here’s YOUR Chance to Learn DRAFTING This Complete $15 Draw- ing Outfit and Full Instruc- PREe tions in Mechanical Drawing There’s a good ‘ob es for you. The country is ie. greater prosperity than it has ever before experienced. Far-seeing menare getting — for boom times. Get this train- ing —— 1 share in the coming prosperi Men Wanted AT BIG SALARIES This is a rare chance fora few wide-awake youngmen On account of the rapidly in- creasing demand for trained draftsmen Pres. Morey has is- sued orders that instruction be furnished to a limited number of young men who are inclined along engineering or architec- tural lines. Read about this great offer below—then mark and mail the coupon, STUDY AT HOME Devote your spare hours for a short time — and learn this art and pleasant profession, and get in the class draw- ng the big pay envelope. Hundreds of men are in daily sistemas at this old established college. In your own home you can do the same work these men are doing, and the same experts that teach them will guide you toward the big job. These well known engineers _—— your instruction matter. Your work is examined and approved a They know exactly the practical Lee ment ou need and they train you. No books to sell. Live, up-to-date blue prints of work in actualconstruction. In your own home you work with plans of machinery, buildings, steel work, etc., actually being constructed in Chicago, New York and other large cities. ELECTRICAL DRAFTING AND DESIGN No other similar correspondence course in America has a resident college of National reputation back of it, nor a faculty of active experts actually enga in municipal and corporation engineering work. These men know exactly the kind of training you need because they are iu constant charge of big work. $45 COURSE FREE IN MECHANICAL DRAWING This College has set aside a limited number of Free Scholarships and will give the regular @45 Course in Mechanical Drawing Free with any one of the Home Study Courses named in the coupon below—this is in addition tothe complete @15 Drawing Outfit which is also furnished to students free, Take advantage of this unusually liberal offer today, as it will be withdrawn when the allotted number of Free Scholarships has been awarded. It costs you nothing to gct full information. No obligation on you. ACT NOW—FILL OUT COUPON TODAY —Electrical Drafting CHARLES W. MOREY President of the College and Head of a Large Chicago Firm of Civil, Mechanical and Electrical Engineers and Contractors. —Builders’ Course —Machine Drafting —Plan Reading —Architectural Drafting —Estimating —S8tructural Drafting —Sheet Metal Drafting —Civil Engineering (1013) -—Surveying ING@MMe. 2. ccccccccccccce ccccccccces: cocccccecece eocccccccccc cece coccee Address ... ...e0 .sseee oe ce ccccee cece wees eecees cecees cocees TOW2D....ccccceccccccccce sees cocccccees cece esStMt® occcccee-coccsece College or Home Study Course ....0..scceessssscceseees CHICAGO TECHNICAL COLLEGE 1013 Lake View Building, Chicago, Ilinoi& When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Before Neither Ever Saw a Human Being BOY of three is cast on a desert island—all that’s left of a ship’s company. On the Opposite side of the island a baby girl is cast up. Both grow up; neither knows of the other. How they survive, how they meet—what they think, throws a light on how our prehistoric ancestoy The title of the story is “Primo. dial,” and it is one of many stories—stories that writers like Irvin S. Cobb, Rex Beach, Booth Tarkington, Robert W. Chambers, Richard Harding Davis and others say are some of the begt may have lived—a vivid picture of instinct and need for love. stories ever written by an American author. The Sailor-Author and His Widow As told by the Famous Editor who initiated this movement Some time ago I picked up a copy of the Saturday Eve- ning Post, turned its pages and came upon an astounding story. It was anonymous and told about a sailor before the mast, without education, who, pushed by an inward force greater than he could control, wrote such wonder- ful stories that he became famous all over the world. How he never got any real reward for his work—and how he was getting old—and poor. A reference here and there told me that the man who wrote that anonymous autograph must be Morgan Robert- son. I had admired him and wondered how a man who produced such pure literature could know so much of the sea. And I thought—here is the chance to give Morgan Rob- ertson his long-deferred reward. The effort started by McClure’s, Metropolitan and The Ladies’ World for Morgan Robertson’s benefit will be continued for Mor- gan Robertson’s widow. Will the American public allow this old lady—this gentle widow of our great sailor-author—to pass her declining years in the loneliness and heartache of want? That is what McClure’s, Metropolitan and The Ladies’ World purpose to find out. THE 4 BOOKS FREE Our Offer IF YOU ACCEPT We will send you a handsome set of Morgan Robertson’s best works in 4 volumes without charge—WE will pay for them—WE will pay the cost of getting them to you—and WE will pay a gen- erous royalty to Mrs. Robertson—if you will pay for one year’s subscription to McClure’s, Metropolitan, and The Ladies’ World at less than retail prices and in little installments. ‘» You will receive at once the set of books Send Only and the first copies of Metropolitan, Mc- Clure’s and The Ladies’ World. You then I Oc No wi send us $1.00 a month for only 4 months. And that’s all. If you prefer to pay all at once, send only $3.75 with order. Personal checks accepted. For full leather binding, send $5.75, or send $1.00 a month for 6 months. Canadian and foreign postage extra. Magazines may be sent to different addresses if desired. If you are at present a sub- scriber to either magazine, your subscription will be extended. McClure Book Co., 251 Fourth Avenue, NewYork And, it was just a year ago that The McClure Publis. tions and the publishers of Metropolitan joined forces t lift from Robertson’s shoulders the burden of poverty which had been his life-long portion. But it was not in the great scheme of things that Mor gan Robertson should feel the heart-lift of appreciation, On March 24th, 1915, on the third day of the first vag. tion of his weary life, he died at the window of his hotd in Atlantic City. His last look was at the ocean he loved Morgan Morgan Robertson 2, te Hodertson Wreck Down of The To The Biir-la Sea scriptions. mine, free. Nane so well; the last sound he heard was the brat of the gut upon the shore. } From the beginning Robertson had planned that the material benefit of this distribution of his books should g to his widow, for she had no funds or income other tha what she would receive from this distribution of her hu- band’s books. ; pay, $1.00 month { Oo pay months to te ao ecceccerereeeceeonet ae recccneeresceee When writing to Advertisers please menticu Popular Science ‘Monthly and World’s Advance.

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Besa BEoe g2i88F 3.8 9 ‘a! Dolt Electrically POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 19 The applications of electricity are increasing every day. The man who has an exact knowledge of electrical] science has ever growing opportunity for profit. Ten years ago practically all machines in use were run by steam engine and countershaft, Statistics now show that most of the machines used are now operated by the electric drive. A generation ago gas was the only known means for lighting and cooking. Now almost every modern house is lighted by electricity, and electric cooking utensils are coming more and more in use. Even the steam locomotive, that great achievement of the twentieth century, is being gradu- ally replaced by electric power. Whether it be for driving machines, for railway transportation, for lighting, for heating, for cooking, for a thousand daily necessities, the watchword of the age is “ Do It Electrically.” . Hawkins Electrical Guides = a2, Will Show You How Electrical knowledge means money to you and these books will show you how to get it, Hawkins Electrical Guides are the standard works on Electricity. They cover every single phase of the subject and they are written in a way you can understand, The text matter is arranged in questions and answers, and contains several thousand illustrations. groping for a solution of your electrical problem. You find the answer at once, clearly and concisely. oe A Most Complete Library of Electricity at the Lowest Cost 2 ~ Look at the titles and convince yourself that Hawkirs Electrical Guides tell aga everything you want to know in Electricity, hey are a complete course in Electrical engin- eering, written especially fort’ .e ambitiousman whois training himself for advancement,for the wide awake man who is likely to be called in for work outside of hisregular line, for the man who needs at his elbow, for reacy rcference, an accu- rate up-to-date work onelectricity. Anexamin- ation of these books will convince youof their value instantly. They cost $1 per volume, ‘Lhey are a wonderful buy at this price, and they are the best electrical booksat any price. Don’t take our word for their merits. Fill out the coupon today and the books will be sent you absolutely | FREE for ent own examination. You have | j ; . J 4 seven days full use before you pay acent. aaa —— a” eS ——= in Handy Separate Volumes The binding is in flexible blacie leather Thebooks are easy to handle and easy toread. They fit your pocket and your pocket-book as well. FREE Shipped to You FREE 4 covron = — HAWKINS) HAWKINS) HaWKNg ) | _ HAWKINS t i . JE | GUIDE CUIDE - pk GUIDE CUIDE Send no money. Examine the books first. Decide for yourself that Theo. Aude! & Co. they are the most complete library of electricity ever published, and that you cannot 72 Fifth Avenue ony Sh erage my prey book is —— = itse ones is only $1 per copy NEW YORK mplete setisthe best bargain, Settlemen ay EIGHT NUMBERS ARE READY. a ae eee oe SO ae, Please submit me for exame- inati Hawki El i Easy Payments @ tits (rice §1 each) Ship A . OF . at once, prepaid, the first eight FEW OF THE SUBJECTS Accept this great offer now— numbers ; if satisfactory I agree to sblestrieMachineryMotore—ArmaturesArme today. Each page—every illustra- send you $1.00 each month until paid, cal instrument Testing—Practical Management | tion will convince you of the big ef Dynamos and Motors—Distribution Systems— | Value we are offering. See the iring--Wiring, Diagrams—Sign Flashers—Stor- books first, then decide. If you age Hatteries—Principlesof Alternating Currents | decide to keep them you cé Signature............... imag Convenes hconen: Moers | make settlement at only $1. it Systems—Circuit Breakers—Measur- monthly until paid for. ents—Switch Boards—W iring—Power ie) i og pe eid a a a EMMIS i ccc cnsicinnwamacedewsesemmcarns cove ireless—Bells—Lighting—Rai man I Cc +) iota meg Ace | Mail Coupon Reference Index of the 10 numbers. 7 ° d ay see Business Address “THEO, AUDEL & CO. REW Tonk cy. a SEAL NTT Reference ....,.ccccccccccccsccccccccccccccces DEC, WA When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 7 Grasp This Opportunity to Learn the Auto Business Earn a Splendid Salary or Have a Business of Your Own RIGHT NOW is the time to start. Over two million cars are now in use; nearly a million more next year, and practically no limit for the future. That means wonderful opportunities—for properly trained men. graduates are making good money as Chauffeurs, Testers, Mechanical Ex- perts, Repairmen, Shop Foremen, Demonstrators, Dealers, etc., etc. We have constant calls for more and more men; our graduates get jobs quickly because our school has an established reputatign for practical and up-to-date training. CLEVELAND AUTOMOBILE SCHOOL 12 years of success—oldest and best established Latest Equipment—Individual Instruction. UP-TO-DATE Training in 4 wecks, including repairing and driving high-powered cars; careful, painstaking and Individual instruction; latest types lighting and starting equipment; Knight and all other type motors; new 8-cylinder car here; twin. the way; every type of every part of auto—most completely equipped auto school in America—the most practical, ge. six on perienced and helpful teachers. COME, AND JOIN US. C. H. PRATT, Chief Instructor Over 3,000 TUITION AND BOARD LOW right near the school, with congenial com. pany and surroundings. We help you get located and feel at home. New classes forming; write at once for Catalog M and terms, | Cleveland Automobile School CLYDE H. PRATT, President 2340 Euclid Ave., Cleveland, 9 Are Waiting For Trained Men At 1800 to ‘4000 words. Here’s the proof. employ individual traffic managers. Thousands of shippers are coming to realize their need of an expert, trained traffic manager. But the supply of trained men who know all the ropes doesn’t begin to meet the demand. Thousands upon thousands of men in America are in the wrong job; right perhaps, as far as the work is con- cerned, but wrong where the pay comes in. Few men can be contented in ajob that doesn’t pay well or offer a@ good chance for steady and sure advancement. This is the day when far sighted ambitious men climb out of ruts and seek opportunities where the going is To become a successful and highly paid traffic manager, just three things are essential A common school INTERSTATE TRAFFIC SCHOOL There’s no vivid imagination behind these ss You can a Ye Cal we advertisement if you wis Trained Traffic Men in Demand Everywhere There are 500,000 shippers in the United States. 100,000 of them are big enough to There are now 3000 to 5000 traffic managers in the country. Th leaves 95,000 shippers without a traffic manager to fill one of the most important positions in their entire organization; a man they need; a man that can save them money. PREPARE NOW TO FILL ONE OF THESE SPLENDID POSITIONS Dept. 152 TRAFFIC MANAGER PRIVATE — fill one of them yourself? talking facts now—not theories, We’re rove them before you answer this education, intelligence and training. You don’t have to have “special talent’’. It’s a simple proposition of figures and knowledge. When you have mastered and freight rates you can land in a job paying at least $1800 and if you get in with a big firm, where your ser- vices will save lots of money, you can earn as high as 10,000. This isn’t theory—it’s facts—cold facts. Ask any shipper you know if the trained traffic managef isn’t one of the most important and well paid men in the shipper’s service. Ask himif it wouldn’t bea thing for you to get into. Then send for our free catalog. It tells who we are, what we teach and how we do it. We'll train you to earn $1800 to $4000 a year as a Traffic Manager. FT. WAYNE, INDIANA When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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& —————EEe | Geo at ora eo ) oF EH POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Well or Sick, You Need Autology iMate aR acres et ice M dite RE We consider Autology one of the most wonderful books ever written. —Physical Culture Magazine. I am pleased to announce that both the word and science “Autology” coined and founded by Mrs. Moras and myself and made known to several million readers for the past twelve years has now been adopted in the English language by the leading Universities—See The New Universities Dictionary. Autology is no theory, no fad, no creed. It deals with the practical business of your body and brain as you have learned to deal with the practical business of your home affairs, plants and flowers, your land and grain, your dollars and cents. With it there need be no such thing as pain or sickness in your life. Do you realize what that means? That you may see and know for yourself, write for my free, absolutely free, “Guide to Autology r FE ree Valuable books containing priceless information that everybody needs. Dr. Moras has written a Commonsense Book on Autology, and by so doing, placed the Standard of the Creed of Health farther to the front than any mam who has lived for a thousand years—-ELBERT HUBBARD. I say this isa book. There are men and men; but there is much difference. When it comes to measuring men by an ideal standard there are but few; the same is true of books. Autology, by E. R. Moras, M. D., is a book.—DR. j. H. TILDEN, Editor of ‘‘A Stuffed Club,” Denver, Colo. Autology saved my life. Three of the best physicians here told me I would be compelled to have an operation for Appendicitis. Nevertheless I have had no pain or indications of it since following Autology eight years ago. It has been nothing less thana ‘‘Godsend”’ tome.— Mrs. C. K.G. (Name on request.) IT am getting better of the hardening of the arteries; all dizziness and heart thumping have disappeared.—E. C. C. (Name on request.) : is treated not only in a unique way, in plain, Every Subject every-day language, as interesting as any novel, but it is as vital to your well-living as breathing and eating. Send for the Guide and judge for yourself. Well or sick you need Autology. No matter what ails you . it will pay you to investigate and you will be under no obligation whatever. Address your request for a FREE copy of ‘Guide to Autology,”’ containing a wealth of informa- tion whose health and brain value can’t be reckoned in dollars and cents, to E. R. MORAS, M.D., 516 Sheridan Road, HIGHLAND PARK, ILL. Dr. Moras is a graduate of Harvard University Medical School, ’88; College of Physicians and Sur- geons (Chicago) ’89; Formerly House Physician and Surgeon in Cook County Hospital (Chicago); Professor of Obstetrics, College of Physicians and Surgeons (Chicago). When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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Come to Detroit the automobile center Detroit trained get preference over mall others—Get jobs quick, soon ag ready—because they learn in the home of the Auto Industry. Car manufacturers ep. dorse our school and are glad to get our gradu ates. Men needed everywhere as testers, assemblers, repair men, chauffeurs, salesmen. Fine chance to start your own business—hundreds of our graduates are doing it Earn $75.00 to $300.00 a Month We teach you to handle any auto proposition. Our equipm i plete. Students here actually build new cars hen start te a Regular factory training in all departments. All leading types of starting. lighting and ignition systems. Four, six, eight, and twelve cylinder motors, Lozier touring car for road work, new Cole and eight cylinder King chassis. Detroit Is The Place To Learn Start Any Time Guarantee Detroit has 44 auto factories. Our stu- | Today is better than tomorrow or next dents can go through them. You don’t =. a gg = od the We guarantee to qualify | get this opportunity elsewhere. Make , eee e big auto you for a position as chauf- | faster time and get practical instruction. as ye ag time, why put it off? feur, repairman, tester, sales- Employers everywhere writing to us for now * writ ~— mers Get into it man, demonstrator or garage | men who know the work. WHY NOT | NEws,” ie wan” ana ge ae —r man, paying from $75.00 to | HOLD ONE OF THESE POSITIONS | torial catalog. 3B ca i Better still, jump on a oe geal = a oo S- eh cc YOURSELF? Just read this guarantee. | train and come to Detroit. fs ino" eusly"” °°” “| MICHIGAN STATE AUTO SCHOOL, 724" Betting, 1119 Seldon dv Detroit, Mich. POWER of WILL "iia cont#ins 28 fascinating lessons on how to strengthen the ill, Write for free trial offer. Pelton Publishing Com- pany, 68 Pelton Building, Meriden, Conn. Learn while holding present position. Cartoonists make good money. No matter where you live, our course will fit you in spare time to earn larger salary. Work congenial, independent, interesting. Don’t delay. Write today for full information, 782 Terminal Building National ool of Cartooning, Indianapolis, U. S. A. wae” VEN - 7 Gl Be) GS fy needed y * NOW wo Get the big job. Earn the big salary. Get into the new profession where high salaried positions are seeking the men. Train yourself to’ fill one of these big jobs. There is one or more in every Electric Light Plant. The de- mand is growing daily for Meter Engineers. We have trained hundreds of others and placed them in big jobs. We can do the same for you. Earn $1,200 to $3,000 a Year Just a few short months at home during spare time. You learn while you earn. Course is in- We quasentes % farsi. sen Wen teresting, concise, thorough. You learn all about complete course of iustruction in Elec- meters and instruments. No problem will stump | trical Meter Engineering and train you you. Step into an Electric Light Plant as Meter | without charge, other than tuition as Engineer at a salary of $1200 to $3000 a year. | specified in our Enrollment Blank, un- OUR MONEY-BACK GUARANTEE Our course prepares you for every emergency. til you are qualified to accept a posi- — y y teed tion paying from $75 to $300 a month, Mr. King’s Rise to Meter Engineer Furthermore, we guarantee to assist you in securing a high-grade position after His experience is no different from hundreds of our | you receive your Diploma, If after re- students. He wanted the big job and trained for it. | ceiving all supplies and instructions to He has a fine position—at a big salary. His training | Which you. are entitled, and after ful- makes him indispensable to his employer. His job is | hut wortectie sothCe ents. rand sure the year round. the full amount of your tuition. King Ne ier = 4 Ne .. ie Ree are rose from j a . } fh —_ Full information—Use Coupon. Get ee the School Literature, story of Mr. rn Ft. Wayne Correspondence School . King’s rise, terms, testimony from students and Ft. Wayne, Ind. Dept. 252 - “4 gineer—all absolutely free. Write today, “NOW.” Use Coupon. # gineering. Dept. 252 Ft. Wayne, Indiana / Address . graduates, outline of course, duties of Meter En- io = 2 .... -_ Fort Wayne Correspondence School 9 Name OT ee Oe ee ocesess

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>. Fea ae

POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

—_—_— | New Way in Typewriting Doubles Stenographer’s Pay ds Formerly Earning $8 to $15 Weekly; teomens $25, $35 and Even $50 with Work w Receive fer than Ever Before. What is it slow on the typewriter. ished work. speed—great speed—and accuracy on the machine. ling work on the typewriter. found it is genuine economy to do so. Why doesn’t the average stenographer make more money? that holds so many down to long hours and hard work at a salary of only a few dollars each week? In ninety-nine cases out of a hundred, it’s because they can’t turn their shorthand notes into finished letters or other type- written material quickly enough—it’s because they are too Results are what count. Stenographers are paid, whether they know it or not, for the quantity and the quality of their jfin- stenographer who is making $25 or more a week and he or she aa at oon that - large measure the secret of his or her success has been This is ve hoe be h day. Business men will no longer put up with slow, bung- em: oye A They gladly pay two or three times the former salaries to stenographers who become expert typists, because they have 80 to 100 Words a Minute Guaranteed Increased Salary $40 Per Month The Tulloss New Way has given me a speed of 90 words per minute—more than doubled. Salary in- crease by $40.00 per month, as a direct result. The Gymnastic Finger Training is of the greatest value. R. E. HELLER, 2615 Millard Ave., Chicago, Ill Double Salary Am now Chief Clerk to the Dept. of Parks and Public Property. Salary is exact- ly double what it was when I took up the study of the Tulloss Method. I can only say if you desire to increase your ability and

ay salary you will make no ‘ i \si mistake in ; cn # = ‘he instruction is of the ghes . ANNA 8. CUBBISON, 109 Hoerner St., Harrisburg, Pa. Salary Increased 40%— Then 20% More— Work Far Easier Yours of the 8th. I cer- tainly know that the Tul- loss Course produces ac- curacy and speed—the two great essentials of good typewriting — and puts the student in a position to demand a higher salary. Since writing the letter you saw, telling of a 40% increase, I have had another increase of 20%. C. E. VERRALL, 66 Olney St., Providence, R. I. $70 Monthly to $150 From a speed of less than course, order,

Nothing Else Like It Don’t confuse this New Way in Type- writing with any system of the past. There has never been anything like it before. Special gymnastic Finger Train- ing Exercises away from the machine bring results in days that ordinary meth- ods will not produce in months. And the work is so fascinating and easy that it’s more like a game than anything. Among the thousands of operators who have taken up this system, are hundreds of graduates of business colleges and special typewriting courses—great num- bers were so-called touch writers — yet there has not been a single one who hasn’t doubled or trebled his or he speed and accuracy, and the salarie’ have jumped in exact proportion, So confident are we that the New Way interested, able information, be a revelation, will put you in the high salaried class that we don’t ask you to risk a single penny—if it doesn’t do more than we claim, the course won’t cost you a cent —that is our binding guarantee. Valuable Book Free We cannot describe here the secret prin- ciple of this new method. prepared a book which tells all about it It is a big 48-page book, brimful of eye-opening ideas and valu- If you are ambitious to get ahead—if you want to make your work easier—if you want to put more money in your pay Se) envelope—get this book at once. Tear off the coupon now Mail before you turn this page. 50 words per minute, this Method quickly enabled me to write 80 and over. From $70 a month when I took up the study, 1 was soon drawing $150< salary more- LT «4 / Gentlemen: than doub- led. 2 Please send e me your free 53) book about the & New Way in Type- WS writing. This incurs no obligation on my Part.

A. H. GARDINE 429 a +a 2 Place, Madison, in complete detail, which is free to those Wis, But we have

It will Occupation to THE TULLOSS SCHOOL $292 College Hill, Springfield,

LT Tee UIDOTOUOOECTONOCUOULCUGUOOOOOOOOOOYOOOOQOOCCOONCOEENCELUUAOUOULOQOGOAOO OOOO OOggnaCnngN es Practical Electrical Education We teach by practical work and _ scientific methods under practical working conditions, all branches of Electrical Science and Engineering. Students enter at any time for full or special courses. No matter what your education is, we start you at the very point you are competent to begin. quickly as your ability warrants. We have more calls for trained students than we can fill. Many of our students have started earning from $1500 a year up, immediately upon the completion of their course: Write for Free illustrated catalog and terms today. If you cannot come to us or Home Study Course—% not want to give up your Present occupation, we will furnish you by mail at small cost our theoretical course. Will deduct all payments made when to enter our school at Milwaukee. Get full particulars.

Se! neeri 226 Stroh Per has “ated — i=—— Wis. Se LLU TUNMA MMMM TT SPEAK A:FOREIGN LANGUAGE !!! The War has created unlimited opportunities for those who know Spanish, French, German or Italian, Better your Position or increase your business. You can learn quickly and easily, at home, during spare moments, by the LANGUAGE-PHONE METHOD And Rosenthal’s Practical Linguistry -«,_ (Highest Award Panama-Pacifie Exposition, 1915) ‘ou listen to the living voice of @ native professor the ) Over and over, until you know it. records fit all talking machines. Write for Booklet, particulars of Free Trial. The Language-Phone Method,946Putnam Blig., 2 W. 45th St., N.Y.

, =| =| y our system of individual instruction, you can complete our course as = - = EI 2 mr

IDEAL XMAS GIFT.

I can_make a good penman of you at home during spare time. Write for my ; Fay 3 book, ya! ¥ to Become a Goo Penman.”” It con- FREE Write tains specimens and fi tells how others mas- or it tered_ penmanship by emt oday a beng , geo our hame w e ele- pane he rs Bon a card BOOK. you enclose stamp to pay postage, 4 F. W. Tamblyn, 437 Meyer Bldg., Kansas City, U.S. 8, \ COPY THIS §

KETCH and let me see what you can do withit. Illustrators and cartoonists earn from $20.00 to $125.00 a week , Or more. My practical system of personal indi- vidual lessons by mail will develop your talent. Fifteen years successful work for newspapers and magazines qualifies me to teach you. , Send me your sketch of President Wilson with 6c in stampsand I will send you a test lesson plate,also collection of drawings showing possibilitiesfor YOU The Landon School of Illustrating A and Cartooning 1451 Schofield Building, Cleveland, O. OHIO AUTO SCHOOL Before enrolling with any school, get our proposition. It will interest and please you. Learn the auto business, the opportunity of the 20th Century. Write us. 311, 1521 Prospect Ave., CLEVELAND, OHIO

When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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24 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE BECOME AN EXPERT ELECTRICIAN Earn $2,500 To $4,000 a Year Learn At Home This is the Age of Electrical Miracles! Electricity rules su- preme as the motive power of the world. It’s wonders are growing every day, on every side of us, in every aspect of modern life and industry. Itis opportunity! And still, as Thos. ison says, the field of Elec- tricity is only in its infancy. The student of Electricity today : will startle us with new marvels Former Sales Engineer tomorrow. Right now we need © — } accom eal men who know Electricity. There Manager of company #re not enough electrical work- manufacturing Jenney ers to fill the big paying positions Electric Motors;former open. Every day the call for Sales Engineer of Fair- men grows more insistent. Feel- banks, Lo My Mh ing the pressure of this demand eer, also Presidentand We are now making a_ very Director of the Wicks special offer to students at this Electrical Institute. time. 20 Lessons FREE Special Limited Offer Never before has an offer so liberal been made on a F™ Albert Wood Wicks, Course in Electricity—probably will never be made again. I make it now because at the present time there is an unusual demand for trained Electricians and it is to my advantage to offer exceptional inducements to prospective students. I want to make it so easy for ambitious men that no possible excuse can be had for not accepting my wonderfully liberal offer. But this Free Lesson offer is limited, good for only 23 days. And there are only a limited number of these lessons to be given away free. So send the coupon at once. Let the free lessons themselves prove how easy it is for you to be- come an expert electrician by my methods. I Will Teach You Personally I will give you my personal and indivic aal attention. Makes no difference who you are, where you live or what you do, I will train you by mail to become an Ex- pert Electrician capable of earning $2,500 to $4,000 a year. My instruction is based on my own extensive, practical, everyday experience. I know just the kind of training you need for the big money job. No needless theory—no drudgery. You don’t have to take a minute from your regular work. Your spare moments will do. Short Time—Small Cost You will marvel at the progress you will make under my in- structions. lesson makes you more eager for the next. And in an astonishingly short time you have mastered the entire course and me an Expert Electrician! The cost to you just now is so small as to be insignificant. You can pay the j ay tuition fee in payments so easy that you will scarcely miss money. mre Write Today '"':,,\odss for tun de: FREE and particulars of our amazing offer of 20 lessons Free. Even if you had not planned Coupon to enter the Electrical field don’t fail to get all facts of this remarkable oppor- A. W. WICKS tunity. Send coupon or postcard. No obligations on your part. Act at oe Se) E- En ~ once—while this offer is open. Wicks Electrical Institute, A. W. WICKS, M.S., E.E., Dept. 52, 81 W. Randolph St., Pres. and Director, Wicks Chicago, !linois. Electrical Institute, Without obligation on me whatever, 81 W. Randolph St. please send me full description of your course in Electricity and particulars of your ~ Cotene* special offer of 20 lessons free! et me teach you Rag-Time Piano Playi Mail ‘ou learn easily—in just a few lessons, af eee My system is so simple wen play a real ragtime piece at your 5th lesson, Whether you can play now or not, I'll teach you to play anything in happy ragtime. “‘Money Back Guarantee.” Write at once for special low terms and testimonials. AXEL ee “Czar of Ragtime,” Room 28 6 So. Western Ave., Send now adissues ISTS AND ART “STUDENTS 4 Publishes Cash ments, lessons and articles on Cartooning ae trating, Lettering, Designing and Chalk-Talk, ing. Criticises amateurs’ work. Interesting, helpful, artistic, UNIQUE. It will please we, Money back if not satisfactory. 10¢ a copy $1 peryear. Send $1 NOW, stamps or bill, to LOCKWOOD PUB. CO., Dept.79. Kalamazoo, lich, _/ «A school that for 20 years has been teaching iw men by correspondence to prepare for \9 Ec ot college; to _ better We positions. prevere a E men for Army cours: and Navy examination will Immediatety in for promotion or your earn. admission to , ing power. either acad- 4 : Write for booke — let “‘C.”’ Address ~ Maryland Correspondence School, Union Bridge, Maryland. Learn To Be a SHOW CARD WRITER Unlimited demand, $18. to $45. a week. Pleasant, Fascinating, Profitable work, Earn money after first few lessons. Ex. ert teaches personally by mail, $1.00 per esson. EASY SHOW CARD SYSTEM Dept. M, 105 Chambers St., New York EARN TELEGRAPH Morse and Wireless—R. R. Accounting (Sta- tion Agency) taught. Splendid opportunities, Positions secured. Marconi Uo. takes our wiree less graduates. We own and exclusively_ occupy two large modern buiidings equipped with R. R. an W. : - M i Wi Sta' oe cialis. Ex Pa easily earned i ents v y paym % spondence courses also. Catalogs Free, Dodge’s Telegraph Ry. & Wireless Institute 10,000 MEN WANTED FOR GOVERNMENT POSITIONS, $70.00 month to com- mence. Annual vacations, short hours, no “layoffs”; common education sufficient; over 12,000 appointments coming; influence unnecessary. Send pean immediately for free list of positions now obtainable. Don’t let this chance go. FRANKLIN INSTITUTE, Dept. D-111 - - Rochester, N. Y. full of undeveloped power, capable of mastering the forcesabout you. Ifyou arenot getting full mental and physical efficiency from your mind ond base, Se wires are crossed somewhere. | LEAVITT shows how to regain and retain abounding, bouyant Health. It tells how to develop your dynamic forces; how, to get perfect adjustment. Its vital has helped others to complete self-mastery--why not you ? 24c in stamps brings this hand- some 48-page de foxe k. Write to-day to C. FRANKLIN LEAVITT, M. D. Suite 949 14 W. Washington St. Chicago Splendid opportunities. Pleasant work, short hours, all holl- days off, yearly vacation with pay, good salary. nna Diploma in six months. Catalog free. EDGARG. ALCORN, Pres. American Schoo! of Banking, 439 E State St.. Columbus, hie ——— carry fs a NS CN |

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ee a. s w/t. POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ELECTRICIT CONDENSED COURSE IN ELECTRICAL ENGINEERING Complete in One Year Bliss Electrical School Studies restricted to theoretical and practical electricity, mechanical draw- ing and necessary namaneing, work. Teaches simplicity, concentration, hard work. or young men of energy and character; 23 years of greatest success. Graduates hold first-class positions. Opens September 27th. Write catalog. fot GAKOMA AVENUE WASHINGTON, D.C. a a nen a READ BELOW PARTICULARS FOR FIRST LESSON FREE 1 Will Teach You Engineering, Technical Work, ACHINE DESICN, Etc. This is the best course ever publicly offered. It inciudes work and drawings made by me for the past 27 years for U. S. and foreign governments; also large concerns. It con- stitutes a complete study in all branches of machine design, mechanical drawing and real shop system. None of the usual cor- respondence cut and dried material. It starts at the beginning, takes you through the simple geometrical problems and gradu- ally advances until you have a thorough training in machine design and a fair knowl- edge of U. S. and foreign patent laws. S Mail a postal for the first lesson FREE. Pay as you learn. Terms arranged to suit yourself Consulting Engineer, 12 meigs Bids. Bridgeport, Conn. | Be a Doctor of the 'CHIROPRACTIC «gx re FOUR INTRODUCTORY LESSONS Q\ > These books take you completely through this X wonderful science of spinal adjustment. Read like fiction, yet absolutely true. 30,000,000 Americans support Chiropractic. Thousands being cured of long standing diseases by it. Resident and Home Study Courses. © BIG OPPORTUNITY FOR AMBITIOUS MEN AND WOMEN Profession not crowded. Large demand for practi- tioners— to $5000 yearly. Small expense. payments. We fit you forall State Board Requirements, Hubbard's Book “ The New ”* Mail postal now and get all 5 books FREE. Do it todays Wa 421-427 So, Ashland Bivd.. Chicago i »R-12 jan le en ed r—> LEARN TELEGRAPHY at home in shortest possible time. Morse or Wire- less. OMNIGRAPH AUTOMATIC TRANSMIT- TER, connected with Sounder or Buzzer, sends you messages at any speed, just as gt» expert operator would. Adopted by »U. S. Govt. 6 styles. Catalog free. OMNIGRAPH MFG. CO. 39-H Cortlandt St., New York. LEARN Automobile Business Hundreds of men all ower the country lose their positions because they are untrained i know one trade well. Milwauk MILWAUKEE MOTOR SCHOOL 1-223 wn eote Wt Beek NEW YORK Complete Classes in all branches of 8 mechanical and civil engineering an ag sr Leading institute with short, systematic, mod- studenten Catalogue on request. Boarding homes for young man in Ep classes for mechanics or em any branches ire crating, ENGINEERING tool - —— . ying, mistry, mathematics, etc. raftin also through correspondence. - 4 and 6 West 125th Street, New York, Corner Fifth Ave. Outfits Free! ES, we give you these splendid outfits abso- lutely free. The Signal Engineer’s outfit is actually a miniature railroad system, complete with block signals, and with it you will get the same kind of practical experience that you would get if you were working on the railroad. The draftsman’s outfit consists of genuine working instruments complete with board and everything that is neces- sary for you to do expert drafting work. There are no extra expenses in the course of the Department of Signaling. Send the coupon for the new book. It’s free, Be a Signal Engineer Our profession is not over crowded. We are calling to ambitious men and golden rewards are offered. Thousands and thousands of miles of track must be equipped with block-signal systems. Are you going to be one of the men to fill a high position, Youcanbe! You can get just the kind of training that you need right in your own home during your spare time. $1252° to $30022 a Month That isan ordinary salary for Signal men. Many Signal Engineers make much more. Supervisors, Maintainers, Inspec- tors—men in every department of Signal Engineering profession, are holding high positions. Youcan fit yourself forone of them. | Two Big Send the coupon for the book which tells about the golden oppor- tunities that await men who answer the call of our profession. Send the Coupon — for Big New Book / ot Sicnaling A i Put your name and address inthe # sosemnne =e = or on a letter or post card and ri Ravenswood Station send tous immediately. Opportunity @ Chicago, Illinois is calling you. The profession is rd i calling you. There’s absolutelyno Gentlemen: Please send me obligations in getting the book, # absolutely free and prepaid but it carries a vital message’ @ your new book on Signal En- to you. Put yournameandad- @ gineering. Also full particulars dress in the coupon now. Do g” bout your great special free not delay. Thefirststepto- ,@ outfit offer. It is distinctly under- ward the realization of ra stood that I assume no obligations your ambition is tosend ,@ Of any kind. the coupon. Doit now. 7 Ravenswood Sta. Chicago, Illinois When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Superb Brunswick ‘“‘Baby Grand”’ With Convertible Cushions For All Carom and Pocket Games 33 Rollicking Billiard Games! Play Them at Home on The Brunswick “BABY GRAND” Play “Little Corporal”’—it’s immense! Play “Golf,” “Cowboy,” “Rotation” or “3-Ball Carom.” It’s no task to learn any game of carom or pocket billiards—the trick is to win. These manly contests of skill and supremacy keep boys busy nights (at home)—they make men and women young clear through. Play-time is filled with thrilling surprises, spectacular shots, and comical situations that engulf the whole party in laughter. Right NOIV—before Christmas—is the time to put a Brunswick in your home. Then, what matter how bleak the winter wind outdoors? —it can’t chill the cheer in your cozy billiard room, Write today for our de luxe book that gives full details. Jt’s free! 10c. A DAY Superb Brunswick Home Billiard Tables appeal to the expert as well as the novice because they are scien- tifically built. Fast, ever-level billiard beds and quick- acting Monarch cushions, the highest rated in the world. Choice woods richly inlaid and masterful cab- inet work. New low prices—only $27 upward. Popular monthly payments—as little as 10 cents a day. q NO EXTRA ROOM NEEDED “Baby Grand,” “Convertibles” and new ‘Quick Demountables” come in a range of sizes to fit the space any home has. Brunswick “Grand,’’ regulation size, made for homes with a special room for billiards, 30-DAY TRIAL—OUTFIT FREE Try any Brunswick 30 days free. Complete high-class Playing Outfit given without extra cost,—Balls, Cues, Rack, Markers, Expert Book of 33 games, etc. Our handsome book, “Billiards—The Home Magnet,” pictures these tables in realistic colors, gives prices and -full details. Sent free, postpaid. Write to- day, and decide before Christmas. Send This ForBilliard Bookf The Brunswick-Balke-Collender Co. Dept. 23B. paid, your billiard book in colors— “BILLIARDS—THE HOME MAGNET" Names When writing to Advertisers please mention Popular Science Monthly and World’s Advance. 623-633 S. Wabash Ave., Chicago Without obligation to me, send free, post- in Y Ue fe Te li al S( t b b ee ee ee ee ' tp

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ‘The three vital features of your Christmas Grafonola For, of course, your new instrument will be a Columbia, if it is a question of musical quality—of certainty of lasting enjoyment, Judge the supe- riority of the Columbia Grafonola, first’ of all, upon its superb tone. Tone: Tone perfection depends fully as much upon the scientific exactness of the repro- ducing mechanism of the instrument itself as upon the original recording process. The perfected reproducer and tone-arm of the Columbia Grafonola is the crowning achievement in this branch of the art. Once you realize the tone possibilities of the Columbia Grafonola, playing Columbia Records or any other records, we believe you will never again be satisfied with any tone lessfull and true, less brilliant and round and natural, Jone control: With the Columbia you have every pos- sible gradation of tone at your command. The tone-control leaves, built on the one right principle of controlling tone-volume, and the wide variety of needles available, give you any and all degrees of tone-volume, from the lightest pianissimo to the resound- ing fortissimo to fill the largest auditorium, Convenience: Your Grafonola, equipped with the individ- ual record ejectors, an exclusive Columbia feature, is ideal in its convenience. Your records are racked individually in velvet- lined slots that automatically clean them and protect them against breaking and scratching. A numbered push-button con- Way trols each record—a push of the button brings any record forward to be taken between the thumb and fingers. (2) COLUMBIA GRAPHOPHONE COMPANY (F Box L493, Woolworth Bldg., N.Y. This model Grafonola with individual Record Ejector, $110. Prices in Canada plus duty. COLUMBIA ee writing to Advertisers please mention Popular ‘Selence Monthly and Werle Advaac.~—~CS* Monthly and World’s Advance.

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102 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Bausct“lomb BALOPTICON | Be The pleasure and instruction which the ear gets from the talking machine, the eye gets from pictures and other objects own by the HOME BALOPTICON made primarily as a projector of cards, photographs, and various ola Special 400-watt, gas-filled Mazda lamp with opi. cally corrected mirror gives an illumination superior toany. thing heretofore offered, attaching to ordinary lamp socket, Automatic, perfectly safe and simple enough for = to agen fey with bigh-gade scone lens, giving well-defined pictures sharp to the comer, Ideal equipment for clubs and small chenesalll well as the home—not a toy. Price for Home Balopticon complete for the projection of post cards, including aluminum coated screen, only $35. Sold by optical and photographic supply deales, Other models to meet any requirement, $20 and up, Write for our booklet ‘‘Fun—and better’’ Bausch £3 lomb Optical ©. 585 $T. PAUL STREET @OCHESTER, N.Y Pictures sharp and brilliant to the corners—not ~ dull and hazy. Jiat object ; holder, ; really sensible gift for a man This Searchlight Shaving Mirror with its strong, steady, generous flood of bright electric light is just the gift a man will be certain to appreciate. Concentrates the light below the eyes—on the face and neck where it is needed most; no glare in eyes or mirror. Makes shaving easy, Useful on the dressing table, too. The Durham-Duplex Domino Razor with white American ivory handle, safety guard, stropping at- # tachment, package of six of the famous Durham- # Duplex double-edged, hollow ground blades in genu- ine red leather folding kit. : SOLVES YOUR CHRISTMAS PROBLEM §| Sh aving $5 Domino — RAZOR FOR $1 4 Combination mirror and electric . lamp with adjustable reflector We are requesting the owners of Durham-Duplex Demonstrator Razors to pass them along tofriends, 4 ets “ap — or at least to tell their friends about the shave itis % | PingJomely’ nickel-nlated frame? possible to obtain with the wonderful Durham-Du- Stands or fe 3 at pn angl “a plex Blade. This is good advertising for us, and we be used Pcs: ho ies oe te id are paying for it by giving Demonstrator users an ioe , avel- opportunity to obtain a Domino Razor for $1.00, with twenty United Profit Sharing Coupons. Just send $3.50 erento oe a ere een mee ee ee Se ce eee Order To- and we will ship DURFAM-DUPLEX RAZOR CO., Jersey City, N. J. this _ Searchlight : . Shaving Gentlemen:—Send me a $5 Durham-Duplex Domino Kit ‘ 6 Outfit as per illustration above for which find enclosed $1.00. day By Mail . —. = Prepaid once, all charges paid, to any address you name. Mirror come ready to use, handsomely packed in an attractive gift box If ena ; you wish, enclose your gift card, when ordering. im aoe | | FEDERAL-SIGN SYSTEM (ELECTRIQ) Any dealer will honor this coupon 7 _;7 Lake and Desplaines Sts., Chicago, Illinois Name When writing to Advertisers please mention Popular Science Monthly and World’s Advance. t : ; t en ie oe a t, ‘é er

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B7R6— FT ? ee te @ fil _ om fies MES 42°F POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 103 RC ——— Weavers of Speech Upon the magic looms of the Bell System, tens of millions of telephone messages are daily woven into a mar- velous fabric, representing the count- less activities of a busy people. Day and night, invisible hands shift the shuttles to and fro, weaving the thoughts of men and women into a pattern which, if it could be seen as a tapestry, would tell a dramatic story of our business and social life. . In its warp and woof would mingle success and failure, triumph and trag- edy, joy and sorrow, sentiment and shop-talk, heart emotions and million- dollar deals. The weavers are the 70,000 Bell op- erators, Out of sight of the subscribers, One Policy these weavers of speech sit silently at the switchboards, swiftly and skillfully interlacing the cords which guide the human voice over the country in all directions. Whether a man wants his neighbor in town, or some one in a far-away state; whether the calls come one or ten a minute, the work of the operators is ever the same—making direct, instant communication everywhere possible. This is Bell Service. Not only is it necessary to provide the facilities for the weaving of speech, but these facil- ities must be vitalized with the skill and intelligence which, in the Bell System, have made Universal Service the privilege of the millions. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES One System Universal Service When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE OVS "Christmas Question Answered For weeks he has been hoping that his Christmas presents would include Ives Toys. And, of course, his dream is going to come true! Watch how he “bubbles over” with hap- piness on Christmas morning when he sees his Ives Train and Ives Struktiron. They’re gifts that enthuse any youngster. Boys—with an Ives Railway you lay the track; arrange the switches, semaphores, Stations and tunnels; couple the engine and cars; stop and start the trains and do everything that is done on a real railroad. With Ives Struktiron you build strong steel models of railroad bridges, elevated railways, sig- nal towers, cranes and derricks operated by the powerful Ives electric motor. You can also con- struct hundreds of other practical models, such as aeroplanes, revolving shovels, battleships. Toy, hardware and department stores sell Ives Trains ($1 to $25), and Ives Struktiron ($2 to $30). Ask to see them. _ Write for Catalog and names of Ives dealers in your town, Poster Stamps Free Twelve of them—beautifully llus- trated in colors. Six show the develop- ment of the locomotive from the famous “De Witt Clinton’’ of 1831 down to 1915. The other six show remarkable Struktiron models. Absolutely free to any boy or parent. Write now (giving toy dealer’s name) for complete set. The Ives Manufacturing Corporation 203 Holland Avenue Bridgeport, Conn, It’s great sport to build ‘Modelit’’ suspensi ; observation towers, steam rollers, treliey’” eeu prides and a hundred other things, We give you all Darts on aap liye complete gy Think of the fun build n skyscraper just like the Woelwort i fs simple with ‘‘Modelit.”’ ee All parts making up the outfit are nickel and finished brass and every part is mechaninaa ae curate, A high-grade Electric Motor free with most outfits, See **MODELIT’’ At Your Toy Dealer’s Santee Tf your dealer does not carry ‘‘Modelit’”’ send us his fame and we will send you illustrated circular. It shows & great many instructive and fascinating models which can easily be made with ‘‘Modelit.’”” Write today. The Watrous Mfg. Company Dept. M EAST HAMPTON, CONN, | | To Run Models; Xmas _ Tree Illumination, Etc. OR every purpose requiring @ low voltage, you will be sur- prised with the efficiency, the compactness, the mechanical perfection of design of VIKING Toy Transformers Write for our new BULLETIN NO. 5, which gives more valuable detailed informa- tion about toy transformers than was ever before published. Answers every question you want to ask. FREE. Send postcard TODAY. Viking Elec. Co., 150 Chambers St.,N.¥- When writing to Advertisers please mention Popular Science Monthly and World’s Advance. aa Gen ~*~ TF et he i dail,

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 105

BOYS—Get this Free Book FREE One of the greatest books for boys ever written. A live-wire story of the struggles and success of a real inventor. Tells E all about how he won out. It’s a story, not a catalogue— FR you get that separate. It’s Free. Just send five boys’ names and addresses; don’t send any money or

t d get the book with full information abo FRANK Horny | stamps, and ge ne DOOK Wi nformation t ¥ y 144 pages. MECCANO. aia THE BOY WHO MADE 12 Charters. 1 FRANK HORNBY MECCANO CO. , +1,000,000 Size 344"x514”. WITHA TOY

Cloth Bound. Room 20, 71 West 23rd Street 52 Pictures. New York City 6 Page Photo- phs, ee uA y=

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a“ BOYS-—yYou Can Build All Kinds of Toys Easier, Quicker and Better With MECCANO Boys, you can build any kind of a model you want to Boys—you can get the MECCANO Electric Motor—the ioe aay tes tet iee'seal fem to le wee $h00 and $7.00.” Irs a seal’ santa cneine Wal goat . E . le -00. al elec r You can nase ce —. you be engge 8 ee wheels = shafting; makes models run “like ‘veal mee correct models easier, quicker an etter, because MEC- chines, ifts 30 pounds; runs on dr i CANO girders are ready to use; strong and rigid. Every - 4 ae Se part is inter-change-able; the equidistant holes (%” See MECCANO in your dealer’s. Took over the outfits; apart) in MECCANO parts allow unlimited inter-change- many sizes, $1.00 to $36.00. See all the fine parts you ability; you can use each part in any way you oh. get; see the 1915 improvements, too. If you have yas z ee ses more and better parts, c4\. fae tek poo the ae Accessory — 00; flanged and sector plates, bent strips, flat cf \: , and contains the new parts. s strips, brass gears, wheels and pulleys, couplings cA: for an Entry Blank, too, and enter a model and cranks. Lots of fine parts you won’t find else- kas in the where. MECCANO _is . \s fae = fa 1% $1,000.00 10,000 —— MODELS were entered in the last prize _—— ;just

Prize Contest Now On! Wine : IR: NG q Don’t miss MECCANO! It’s the one best ent things ‘ 7~ ( constructional toy. And be sure and ¥ i " 6 f send for the fine book offered above! makes. i

Get _MECCANO!

Boys— > Get Busy With MEC- cAN O— : : Build all — kinds of hae. hi. models, » \ ARE ne ee

Boys— Be sure and see MEC.- CANO at your Deal- ers, Renee es EEO ot USER ERES = —— a Don’t forget to send < — —— BOYS— Noe aber Get MECCANO for Xmas!

When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE The Christmas Present A Practical Gift That Is Pleasure-Giving Barney & Berry Skates “Used For Fifty Years Wherever Water Freezes” Make your Christmas one of Mutual Merriment. The wearer of the famous B & B skates will experience exhilarating, healthful sport, and will glow with satisfac- tion that there are none better. No other gift is so generally acceptable. Send for our new catalog, containing hockey rules and directions for building an ice rink. It illustrates the “Amer- ican Club,” the “International,” the “All Clamp,” the “Continental,” the “Tubular Hockey,” the “Canadian Hockey,” and others. You can select whatever style you desire and order from your dealer. BARNEY & BERRY 139 Broad St., SPRINGFIELD, MASS. aa 1, y, ] a steering me er dy me ? Flexible Flyer g) but-be sure tts @ LEP Stronger, easier than ever to control, All-steel front and chrome-nickel steel runners give added safety, durability and ease in steering, The fastest and safest sled made. 4 feet long. JUNIOR RACER WWevgns 16% ws. $3.50 Express prepaid east of Missouri River, The Flexible Flyer comes in nine sizes—3 to 81g feet long, Outlasts Three Ordinary Sleds Insist on the genuine—¢?¢ sn"? eZee a Flexible Flyer uniess it bears {QEXIBiR SP Re this trade mark, te Sold by Leading Hardware- and Dep’t-Stores. Cardboard model showing how the Flexible FREE Flyer steers. Also attractive booklet. Write fog * them today! S. L. ALLEN & CO. Box 905L Philadelphia A MECHANICAL PUZZLE SPEEDWAY VW AC UUM Enente WHAT MAKES IT GO! Few have been able to answer correctly. A PERFECT TOY that ‘“GROWN-UPS” will enjoy A Real Engine in miniature built of high-grade steel and castings, carefully machined. Has 1-in. cylinder, 1\%-in. stroke. Runs at 2000-revolutions per minute. Simple, instructive and safe. Many interesting experi- ments can be made with the Speedway running builders’ outfits and other toys. *MOIA 199304 SALT 03 gno Jo yNo 332] SPlelys ouwy opduy PAT. MAY 8, 1911 Price, *3-5° Ask your Toy dealer for the Speedway—if he has not got it we will send C.O.D. charges prepaid anywhere in U.S, SPEEDWAY TOY MFG. CO. 216 Gibbons Arcade Dayton, O. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

¢ Fei: Sy ge Ch ALY: a4 QS %, yt

a ee aed actric Candlesticks Silver-Plated, Colonial Pattern peur handsome Electric Candlesticks are just the thing for the Holiday season—splendid for gift pur- poses as well as for use in one’s own home. They combine all the charming decorative value of the old-style candlestick with the safety, convenience and cleanliness of modern Electric Light. Can- dlesticks will be more popular than ever this year, and they must be Elec- tric Candlesticks, to be really up-to-date. The Pair Illustrated Above, Sent Complete, $6.80 These Electric Candlesticks stand 10-inches high, with 6- by ,/ ° 234-inch oval base. We will send the pair above illustrated, oF ready to use, to any address upon receipt of $6.80, shipping ©

mi -charges collect; completely equipped with two 60-watt nat- 2" ot ural-frosted spherical lamps, two silk shades and long silk cord (wired fs s ii =«together, with single plug). / 2 9 | aa e prices on a shipping-charges-collect basis. ) S ow an &y or Se y &Y

Please Use Attached Coupon When Ordering Write name and address plainly and specify clearly which selection *S y s you make. To insure safety, remittance should be made by postal Os 2 roe os = Y or express money order or bank draft; if currency, it should ) 2 woe FF PF Sd be sent by registered mail. YY ¥£ yy x + oF RO ’ yY i v Py ELECTRIC SHOP—CHICAGO a A Y Se oe KP Ke Kv Oy S SS Sr CH Ys e e is) & PS & & A ; , Corner Michigan and Jackson Blvds. i ro owe oe SY YY 4 os & & &. at ri “ a eee se eeRPee ee Ree ee Cx FM Pedagie 4 / ed Fl Ss = =eeeseeeeeeueeeaewmueeeeeeeene ee ‘i 4 ry . & x oe oo eo oo m ‘ E

When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

the new scientific sport.

Taube.

With an “Ideal” Construction Outfit you can easily build a perfect 3 FT. WAR MODEL AEROPLANE —a real miniature flying machine with “which you can have lots of fun and intensely fascinating instruction in the great science of aeronautics. ‘“Tdeal’’ Construction Outfits are made for all types of aero- planes. ‘They include all the necessary parts in knock-down form with simple, easily-understood building and flying direc- tions and exact scale working plans, “IDEAL” TAUBE MONOPLANE An exact 3 ft. scale reduction of the famous German military machines playing such an important part in the EUROPEAN WAR. Outfit consists of rubber-tired disc wheels, ball-bear- ing propeller shaft, hand-carved wooden propeller, etc. Guar- anteed to rise from the ground by its own power and fly. De- livered complete, ready to assemble, all charges paid.. $4,25 A Present That Every Boy Wants Build An Aeroplane That Flies! Thousands of boys, and grown-ups, too, are racing model aeroplanes that they have built themselves, It’s 3 ft. Bleriot Monoplane; outfit 3 ft. Curtiss Military "Tractor: with all parts, ready to as- One of our most interesting models is the outfit with all os ready t, GEMble ..cccsesccccccscccecs $4.25 ASGEMDIO 2... ccccccccsescsh $5.00 3 ft. —<$—

Nieuport Monopla: * fit with all parts, ready to ay semble -$5.00 Scale drawings and instructions alone for all our models are offered at following prices :

CURTISS MILITARY TRACTOR ........cceeeeeeee 25¢ Curtiss Flying Boat ......c.cecccccccccccccccscccces 25c Curtiss Hydroacroplane ..........cecccececccescccces 35¢ Nicuport Monoplane ccccccccsccccccccccccccccocccces 25¢ Aeroplanes and F lyers. SPECIAL: Complete set of above 8 plane $1.60 There’s a toy, game or department store near you at which you can get “Ideal” Model If you can’t find the store, write us. Write today for our 50-page Aeroplane Bock, containing full Information as to long distance ; complete models, etc., postpaid, 5c. , wasere, qrioes ter ce IDEAL AEROPLANE & SUPPLY CO., EE NOUNS oo vas xcs isaic's 0 cases wewon l5e WAUBE MONOPUANE oc.cccsssc0ccccccccoaccscsne 25¢ NI IND oo 65 nares Wictmie in 420 gts see ee ae 5e SOON EE RIPE 5 ons occ vv eicdes oie secs voces See 256 80-86 West Broadway, New York City

Boy Electrics KNAPP MARVELECTRIC THE GREATEST

Every Boy should have one. More fun, more information than a hun- dred books. Finished as shown. netism, Solenoids, Dynamos. Price $3.75 Live dealers everywhere. Order direct, or ask your dealer to show you the Knapp Line and insist on getting Knapp Goods. Dealers not already handling the Knapp Line should ask for prices. Catalogue illustrating many specialties on request. Knapp Electric and Novelty Co. 517 West 5ist St. N. Y. CITY Demonstrates Mag- Resistance, Motors,

" 50 Light Dynamo, $60. $60 \ »). 1 00 6“ 6 $80 In Payments of $5 Only Per Month HOBART BROS, CO, TROY, OHIO MAKE YOUR BIKE A MOTORCYCLE at small cost by using ¢ our Attachable outfit,

tools required y for bargain Y FREE BOOK ¢ Pres Ao a SHAW B Bene otor Attachment. cycles, all makes, new be second-hand, $35 fe up. SHAW MANUFACTURING CO. Dept. 36 Galesburg, Kansas

lerwal — ce. | BRASS GEARS Cut byan entirely new process. The Ys accurate made and at prices that cannot be equalled by —. Every gear has = center painted ebony ‘yo true, highcet grade red brass, heavier than others. We carry stock in the world, and every gear Usted is always shipped on date of order. SEND FOR CATALOGUE ag o—~? —_ WORKS 8 So. Fifth A ; FORD RACE #5 REBUILD YOUR FORD We Sketches, Specifications and Prepaid for twenty-five cents. ia Dept. B. Box 212, Woodfords, ‘se iy Ht i : i

When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

ERS

Page 195

rre oO Ve be Ral ; al: POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Peo y LOOK ay ff 7, me} ‘i Eiaee a cars; get switches, semaphores, electric lights, track, etc. a touch of your finger. I t multivolt transformer, which saves. Batteries. e—no shocks. They’re steel—not_ Cast wt] throughout, but not high priced. Write Quickly for New Boys’ Catalog-—written specially for YOU, crammed full of pictures, New photos tell you why you'll have such a dandy good time with Lionel Trains. , Section of Lionel Rail Free—Most toy dealers, electrical stores and department stores sell If you'll go to your toy dealer, find out if he sells Lionel Trains, and tell me when you write for catalog, I’ll include a special section of rail—free. Lionel Toys. J.LIONEL COWEN A Friend of Boys, Pboys- Res Fug FREE cB Sc-/ 1 ipenee Stine? 'S, Ch SSeS Write Quickly for Catalog , th a Lionel electric locomotive; couple to it Pullmans or freight You'll eeaeate of Sn wi i ake the trains scoot around with Run ’em on batteries or from electricity in your house with a Lionel (See illustration.) hem—join us—this quarter-million of happy boys. 250,000 hays own ; ‘s Iron—and wart break. Unconditionally guaranteed, Finished handsomely in colors and gold. Models are faithful reproductions of originals seen on our prominent rail- roads. FOR Lionel Electric Trains Are highest grade of If you Have Electricity surely Get this Multivolt Transformer THE LIONEL MFG. CO. 48-J East 21st Street NEW YORK CITY No More Battery Troubles THE CAMPBELL TRANSFORMER $2.00 Does away with all bat- tery cost and trouble. Will ring bells—oper- ates door openers from electric circuit. Easily installed and cannot get out of order. Low cost plus effi- cicncy. Throw away those old, troublesome batteries. Try the Campbell Transformer —it’s guaranteed. .Write for list of electrical specialties. Campbell Electric Co., Lynn, Mass. ELECTRICITY IDEAL XMAS GIFTS BOYS—This book is a mine of electrical knowledge, 128 pages full of cuts, complete description and prices of the latest elec- trical apparatus for experimental and prac- tical work—Motors, Dynamos, Rheostats, Transformers, Induction Coils, Batteries, Bells, Telephone Sets, Telegraph Outfits. Greatest line of miniature Electric Rail- ways and parts, Toys and Novelties. This catalog with valuable coupon sent only for 6c in stamps. (No postals answered. ) VOLTAMP ELECTRIC MFG. CO. Park Buildin Baltimore, Md. i : EMS LRWANTED Send us your verses or melodies today. E ience unn Acceptance for publication guaranteed if available. Wri 2 te for free valuable booklet. MARKS-GOLDSMITH C0. Dept.92, Washington, D. C. BOY S---Get a Loop the Loop Glider for only 50 cents and duplicate the feats of World Gueed oe Famous Aviators. Will positively LOOP THE LOCP and —— - perform other marvelous feats. Our GREAT = ag eS ce ge AEROPLANE HANDBOOK free with : each glider. ~. Sake THE MODEL SUPPLY HOUSE, W.H.Phipps, Dept.L, 503 Fifth Ave., N.Y. at Throw Awa dene Worn Tires” You can get 5,000 miles MORE service out of them. For over three years European motorists F have been getting from 10,000 to 15,000 miles out of their tires by “‘half-soling” them with Steel-Studded Treads. In eight months 20,000 American motorists have followed their example and are saving $50 to $200 a year in tire expense. H it t d it We Deliver Free prepay te express and allow you to be the judge. Durable Treads double the life of your tircs and are sold under a signed rantee for 5,000 miles without puncture. pplied in your own garage in thirty minutes. H H ff t torists in new Special Discount e230 ere ment direct from factory. Don’t take any more chances with your tires.Mail the coupon today and find out how to get 5,000 more miles out of them. wae wee ==eJear off and Mail-—Save the Discount=== a= | Colorado Tire & Leather Company | 1249 Tread Big., Denver, Col. L49 Transportation Bidg., Chicago. 4912 Woolworth Bidg., New York. Please send me_ without obligation, sample, copy Gentlemen:- of 5,000 mile guarantee, special discount terms and book ‘10,000 Miles on One Set of Tires’’. EES See oe eee eee men nate or ent | a eee er ae eee Fee eee [ J UL RT } A A SE Se RE SE SE GE OG So SS When writing to Advertisers please mention Popular Science Monthly and World’s Advance. hy

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE |

a

tin explains.

Costs Less Now Besides our lower prices, WITTE Tie (f.azleton where there are no dealers, engines use less fuel, and cost less for up-keep—enoughsaving, WITTE Engines| |§

Gasoline, Kerosene, Distillate, Gas. - 2H-P $34.95; 4H-P $69.75; 6H-P $97.75 ; as 8 H-P $139.65; 12 H-P $197.00; 16 H-P $279.70 ae eee 22 H-P $359.80. Portable Engines Proportionally Low. ‘ —F f.0. B. Factory. Cash or Easy Terms. Sent Direct From Factory Under 5-Year Guarantee Before you buy any engine, for any kind of a ice, let us tell you where, and how, to look ‘or engine quality—the things that make lower- a Seow with easy starting, (no y running and utmost durability. Write us for it today. ED. H. WITTE, WITTE ENGINE WORKS, 2225 Oakland Avenue, Kansas City, Mo. Empire Building, ittsburgh, Pa.

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With 938 Genwue “Stamps, incl, Kho- examination and fail Stamp Album Yeie, Congo. (ger), China (dragon), Tasmania (landscape), Jamaica (waterfal s), etc. (0c. List Free. We BuyStamps. « HUSSMAN STAMP <0.. = - St. Louis, Mo.

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No. 68 Carleton Generator 7 Volts 7 Amperes (49 C, P.) solves the lighting problem, Steady light with or without storage batteries Special brackets for Ford, and Metz cars, but easily applic. able to any car, cycle, boat op miniature stationary plant. est quality construction and mod- erate price; not to be confounded with cheap, permanent et generators. Also Automatic (yt. outs, Storage Batteries, Go and Ammeters. Descriptive Bulls. SPECIAL 12-Volt, 10-Ampere Gen. erators for boats or stationary work, Local demonstrating agents wanted ompany 178 SUMMER, BOSTON

New Book Free fels.2sity, tow, te == Course On App Not one penny down. Get this greatest home-study course law—including this maguiticont fourteen-volume library, the | om its kind in existence, and the first lectures, in. dividual lessons, assignments, etc.— clear, comprehensive discus sions of the law—in your hands free of charge—without any obligy. tion whatever. We want you to sce this course, before you decide. Write a postal—right now—to get the details startling offer—to find out how. you can, without risking Get Your Degree By MAIL! We are authorized Py the State of Illinois to confer on ow achelor of Laws (LL.B.) prepares you to pass the bar examination in any state. Should you fail we guarantee to coach you without charge until you are successful. We have not on record a single instance of @ graduate who took a bar FREE Complete Course in Public Speaking pared by Dr. Frederick B. Robinson, Prof Speaking. College of City of N. Y. etc. No other course like it ite today for Special Limited Free Off SEND NO MONEY Just send por name and address ona postal, and we will forward by retum mail full culars of our remarkable free on approval offer and = — erful | pa — Mee ag the i shown Sa aw at home. ou mptly we will save yowmore : Ys offer is subject to withdrawal in e short tine, LaSalle Extension University, Dept. 6-120 Chicago, it

We say the Bessemer Kerosene Engine is cheapest in the long run— because of low running expense. We have a number of tests to prove this, which will be furnished you upon application. The Bessemer is built as a Kerosene Engine, and is not a converted gasoline type, there- fore is freer from trouble and repairs. Sizes 2 to 10 H.P. Also direct connected to pumps, hoists, lighting plants, etc. Get a lot of real facts free by writing today. BESSEMER OIL ENGINE recommended where power from 15 to 200 H.P. is required. Burns

lutionizing the power question. Get the THE BESSEMER GAS ENGINE CoO. 152 Lincoln Ave., Grove City, Pa.

ESS EM E R- ‘racine!

crude and fuel oil and runs at about % to % cost of asoline. Now being used in irrigation, flour mills, factories, +. plants. This engine is revo- acts by writing for Catalog “‘O.

| BEer | rm ie

HX cea

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Estia tT Setters OO eSeS.”.)h—lmltCNO ETE ee 5 feee5s = F | re a re Sst POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 111 ‘Make “100 to $300 a Month Soling and lasting Swartz Electric Home Lighting and Power Piants i engine and generator in one unit. Dea oe Tungsten ligh ts,or currentforchurn, washer, toaster, fan, etc. First plant you in- stall will sell scores of others. Farmers have got the money. Be the first to enter this big, new, growing business in your county. « Write today for folder ‘L. Storage Batteries OME, FARM, THEATRE, STORE, and TOWN LIGHTING ELECTRIC HOINTS. $18.00 Rectifier Charges rage Soc! Lighti ‘o Electrically for ONE -+¥ biaginess seltss ‘Medical and Zrorage Batterie: Machines and Power Motors: Railways 3 , Sewing Auto ; Lights, Massage ana zone jachines, os 0 PICTURE THEATRE TRAVELING AND PERMANENT EQUIPMENTS. fits! 10¢. an hour lights theatre & M. P. Mach,, Cat. 3c, rORKS CLEVELAND, OHIO ELECTRIC LIGHT AND POWER DAY AND NIGHT SERVICE Set No. 409 AT Gasoline Hnsies. Bysenn, Com. | $ an ve ag onl “esnay J 240 =e Complete—reliable—high-grade. We | want arepresentativein every county AMERICAN BATTERY CO. Est. 1889 1143 Fulton St., Chicago Make Artcraft Electric Lamps This Book Will Show You How plete directions for building the different type lamps that are used in a home—from the hall lamp to the complete chandelier. These lamps are very attractive, employin wood, art glass and metal in their makeup; stil their construction is so simple as to require only ordinary tools and workmanship. “How to Make Artcraft Electric Lamps,” also contains directions for working copper and brass with a design for a hammered copper table lamp. Clear, concise instructions and large working drawings are features of this book. Popular Science Monthly A splendid series of designs with com- Twenty-Five Cents Book Dept. 241 Fourth Ave., New York You should own a Corona A Six-Pound Typewriter for Your Own Use Some people are judged by their appearance and others by the letters they write. Your letter, personal or business, should be neat looking and leg- ibly written to make as good an impression as you would like to make personally. Whenever you have any writing to do, use a CORONA Folding Typewriter At home, in the office, or when you travel you will find it a great aid in conducting your correspondence, writing reports or manuscripts. Many progressive firms have equipped their salesmen with Coronas. Newspa- per correspondents throughout the world use Coronas. Over 50,000 people in. various vocations are enthusiastic own- ers of Coronas. You, too, should own a Corona—use it in the office, at home, or take it with you when you travel. pounds. Weighs only 6 Costs only $50.00. Note thesemodern features Visible writing, ribhon, universal. keyboard, back spacer, aluminum frame, double carriage release, mechanical type guide, ball bearing carriage, keyboards for all languages. _ Send for this New Book It contains the names of hundreds of firms and individuals who are now us- ing Coronas. It proves what this ma- chine does—not what we claim it will do. At the same time ask for Catalogue No. 26. Corona Typewriter Co., Inc. Groton, N. Y. New York: 141 West 42nd Street Chicago: 12 So. La Salle Street Agencies in all principal cities” two-color When writing to Advertisers please mention Popular Science Monthly ‘and World’s Advance.

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112 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE PREST Q-LITE eh ‘MOTORCYC LES: Economical Efficient and. Brilliant Light Prest-O-Lite gives perfect riding light— is as sturdy as your motorcycle itself. It stands the jolts, needs no attention you yourself cannot give. Practical, simple, and trouble-proof. Considering its simplicity and freedom from trouble, it is at once the most con- venient and the most economical lighting system for motorcycles, Complete Equipment for Regular Service Nearly all dealers make this typical equipment combination: ‘‘Prest-O-Lite, a lamp, and a mechanical horn.’’ Costs less to buy and less to use. Your name and address on the margin of this page will bring complete information on motorcycle lighting. Get our valuable free book. Write today. The Prest-O-Lite Co., Inc. The Worid’s Largest Makers of Dissolved Acetylene 838 Speedway Indianapolis, Indiana Prest O- Lite Exchange Agencies Everywhere ——————___ a Simplex Electric Devices Make Ideal Xmas Presents This Curling Iron Heater will be appreciated by any woman. No flame to blacken the Iron with soot and smoke. Quick, Clean, Safe, Convenient, Other Lamp Socket devices include: Toasters, Percolators, Chafing Dishes, Irons, etc. Write for Booklet: “ The Good Fairy of Housekeeping” SIMPLEX ELECTRIC HEATING Co, Manufacturers of Everything for Electric Heating and Cooking 86 Sidney Street eal Cambridge, Mass, Vv TRADE MARK and Playés at Wholesale}; ing Plan, we } offer onein each localityat the rock-bottom wholesale price—putting $200 IN YOUR POCKET Artistic des’ ferfa eee wondes a ee Be" Acme of tal FREIGHT CHARGES ALLOWED. Easy No Mn... orf Stool and Scarf—Two Years’ FREE Course Piano Instructions Write Today, Be the First Story & Clark Piano Co., bz. is» When writing to Advertisers please mention Popular Science Monthly and World’s Advance. exclusive features, vacientifically built, pro- backed by Three Million Capi- payments~ 0. Evans, Go. Mee

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ni} ) ly u. ar re ve ch 1g mS POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE —_—_— Buy Now and Save Money 7 WIRELESS X’MAS Bargain Prices to prove the wonderful values and superior goods we give you direct from SALE our factory. These ridiculously low prices are only made possible by our enormous output for our tremendous trade. All hignest quality, beautifully made and thoroughly tested out. Save 25% If You Act Quickly Here is Your Opportunity to Secure the Best Navy Type Loose Coupler on .00 the Market. Regular Price, $15.00. For December Only--Reduced Sale Price $10 A Thoroughly Reliable Station Our No. 810 Complete . Sending and Receiving Station Regular Price, $20.00 .00 For December, Sale Price Only $14 Sends up to 12 Full 1% inch coil miles. type. Sends up to Receives up to 12 miles. Receives 1 - up to 1,000 miles under favorable con- ditions. Equip- ped with 2 double pole 1,000 ohm re- cord and double headband. Size of base 12 x 16 inches, height 13 inches, weight only 14 pounds, This is a com- pletely equipped and _ thoroughly reliable station, mechanically and . F electrically per- ms fect and ready for instant service. Nothing better in this class was ever constructed. The new improved tuning coil enables you to tune in or tune out any party you might desire, thus eliminating any interference. The set consists of a 1% in. Spark Coil, 12 Flat Plate Condensers, our ‘‘Don’t Jar Out’”’ Detector, Buzzer and Switch to tell if your detector is working. Double Slide Silk Wire Wound Tuner for long wave station capacity, Fixed Condenser, Helix, Key, DPDT Switch and com»lete 2,900 Ohm Headset. Our No. 401 Sending and Receiving Station Regular Price, $5.95 95 For December Only, Sale Price $4 Consists of %4-inch coil, fluted end spark gaps, four plate secondary, one collapsible helix, one key, a two-slide tuner, fixed condenser, de- r and buzzer test to test your mineral. This set is mounted on a highly finished oak base with all metal parts heavy nickel-plated. With & good-sized aerial, under favorable conditions, will send up to 3 miles and receive up to 300 miles. ceivers, 6 -feet silk A brass lacquered 6,000 meter inductance tuner, perfect in every detail. Equipped with four point loading induc- tance which increases the wave length 4,000 meters over the average Navy Type Transformers. The primary winding has 24 taps—one switch controls the primary in groups of tens, the other controls: one turn at a time—and is equipped with a dead end switch. Enclosed in a cabinet, the front of which is pol- ished hard rubber. The secondary coil is wound with double silk covered wire and the inductance is varied by a ten point switch. With this coupler the very finest and most accurate tuning is easily and quickly secured. With a good sized aerial the reception of wave lengths up to 6,000 meters is possible. All Finished Parts Ready For Assembling With Full Instructions. Speclal.............cescscsscoeccsceecesceceees $6.50 Receive the Time From ; AND ALL NEWSP Arlington Ship ‘Reports PE ANP Our Special Time Signal Receiv- ing Outfit _ = $8:1° Regular Price, $10.85 This is our new 1915 model made} of the high- est grade material ob- t a in able Double slide coupler for close tuning is wound with No. 24 wire on tho * primary—the secondary with No. 28. There are 8 points to divide its capacity. A 3,000-metre loading coil placed be- tween the coupler and the aerial by a switch that throws it in or out of the circuit enables you to receive amateurs with the coupler alone and long wave stations by the addi- tion of the loading coil. One fixed condenser of proper capacity, improved universal detector, one buzzer test to test your mineral and potentiometer. This instrument is assembled on a highly finished oak base. All metal parts are heavy nickel-plated, A This station, with our Navy Type Loose Coupler, as illus- trated GDOVO ccccccvcccccccccceccccecces eecceccccce $15. Send 6c. in Stamps for Our Big 152 page Wireless and Electrical Catalog ‘“‘D-40” Containing Hundreds of Wonderful Bargains of All Kinds FREE—SEND FOR BIG ELECTRICAL TOY CATALOGUE—SAVE MONEY X’MAS. FREE—Write our Query Department—vwrite us and we will give you free technical advice : on all wireless questions. NICHOLS ELECTRIC CO.., 1-3 West B’ way, N. Y. Manufacturers of Standard Quality Goods Only When writing to Advertisers please mention Popular Science Monthly and World’s Advance. 113

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114 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE dit CHRISTMAS JOY and permanent satisfaction are assured to those who select their purchases from our new catalog. Every reader will find something electrical to please, to mystify or to entertain. The best the world affords in Motors Dynamos Lighting Plants Meters Spark Coils Electrical Toys Heating Devices Our catalog is a joy to the experimenter; a necessity to everyone, and is boiled down to 112 pages, 100% interesting. IT’S FREE. CLAPP-EASTHAM CO. Manufacturers and Distributors, 143 MAIN STREET $$ SE Cooking Devices Parts and Supplies Switches Motion Picture Machines Phonographs Wireless Telegraph Apparatus A profusion of other things electrical CAMBRIDGE, MASS COVER REMOVED It is a Yy K.W., and is built on the same specifications as to ma- terials, workmanship, etc., as our big Central Station transformers. using these Hundreds of stations are now transformers. This is the Transformer you need to get the result you want This transformer gives you 13200 VOLTS Let us tell you how you can do part of the work yourself and get this excellent transformer at a remarkably low cost. THE PACKARD ELECTRIC CO. 545 Dana Avenue (68) Warren, Ohio “DEPENDABLE? | PRICE polished as shown a orm t it $20.00 $1.50 extra This is one of our new Receiving Outfits In it we have combined Our L 102 Inductive Tuner Our 110 Silicon Detector Our 1220 Fixed Condenser And our special 43 Plate Variable Condenser All the instruments are finished in nickel and Electrose ends are used on the tuner. The Cabinet is made of mahogany finished wood, hand rubbed. There are- name plates for the connections of the Aerial, Ground and Re- ceivers. We do not furnish the Phones because of the difference of opinion of the Experimenters. This outtit will receive Time Signals from Arlington and Key West, with an aerial 60 feet long and 50 feet high, over a distance of 1,500 miles. The Cabinet is 16 inches long, 12 inches wide, and 4 inches deep. It is the best outfit that can be had for less than $50 and for sensitiveness it has no equal. We recommend Brandes receivers for this outfit DORON BROS. ELEC. CO., Hamilton, Ohio d 5c for new catalogue LEARN WIRELESS WE GUARANTEE : First Grade Commercial Operators’ licenses. Last year EVERY ONE of our graduates successfully passed his required Commercial Operators’ Government Exami- nation upon the first trial. Send stamp for new Fall prospet- tus containing free call list, commercial abbreviations, prefixes, etc. Fall classes now forming. Eastern Radio Institute, 899A Boylston St., Boston, Mass.

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I] Eo POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE of signals. we'll gladly refund your money. Send 4c. stamps for copy today. Wireless Receiver Specialists These are Real Wireless Receivers OT merely high-wound tele- phone receivers pressed into service; but highly sensitive, tone- matched, light-weight wireless re- ceivers—designed and tested for great efficiency in bringing in all distances Send for a pair today and try them out against any other make you know of. Try them for long and short distance messages. If you do not find them better—yes, better in every way, in sensitiveness, tone, weight —than any receiver you have ever used, New CATALOG R, just off the press, gives facts you need to know in selecting a ‘Head Set (complete information about different types of Brandes Receivers). C. BRANDES, Inc. Room 813, 32 Union Square, New York, N.Y. BRANDES WIRELESS HEAD SETS **Superior’’ Type Receiver Complete with Headband—-$5 BORER co — The No. 100¢ ‘at : a Brass “ALBANY” Nickel $2.50 Weight 1 Pound DETECTOR December 15th is the last day on which you will be able to purchase a No. 102 “‘ALDANY” Rotary Condenser for $2.50. Thereafter the price will be $3.25, as formerly. @ MAGUIRE & SHOTTON @ 814 LANCASTER ST. . ALBANY, N. Y. . A Wireless Transformers 16,000 Volt. YyK.W..... $ 8.00 14 K.W..... $12.00 34 K.W..... $16.00 Bell, Toy and other trans- formers, send for folders. DISCOUNT TO DEALERS A.R. DARLING 1532 N. Capitol Ave. K_Indianapolis, Indiana To E | DUCK’S ee ead ©2%" Catalog wee §6JUST OFF THE PRESS 40 more pages of wireless Instruments at more attractive prices than ever. Also many new Items In_ electrical —* at substantial reductions in price. THIS UNRIVALLED CATALOG MAILED TO ANYONE UPON RECEIPT OF 8c IN STAMPS OR COIN, which may be deducted on first dollar purchase. Great cost of catalog and low prices prohibit distribution otherwise What This Big Catalog Contains 160 pp. Wireless “Apparatus 5 pp. Lighting Plants; for Commercial and Ex- 10 pp. Ammeters and Volt- perimental use: meters ; 10 pp. Raw Material; 25 pp. Electrical and Me- 5 pp. Transformers; chanical Books; 8 pp. Storage Batteries; 12 pp. Telephone Equipment; 15 pp. Telegraph Insts. ; 10 pp. Auto Accessories; 42 pp. Motors and Dynamos; - Joy "ies pf Mis 10 pp. Miniature Lamps; Plan (No Down Pay- 8 pp. Flashlights; ment) ; 5 pp. Massage Vibrators; 30 pp. General Electrical 10 pp. Miniature Railways; Supplies. THE WILLIAM B. DUCK CO. 224-228 Superior Street, Toledo, Ohio When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR uO H ve 19 O@2%2 Merv 0 a -_— ate 2422 » \ 3418 ag ay oP, =F} | oS | x Ye | Fo ee = Bs | ti mg : — | ail ee | [: yd Y ae! K nif ngin jl | , a a0 =e | ? . a 4 \ | ns) i mt ps eel 1 x4 lt oa A= ZENS ~ —~ i L — 1088 a WIR BO) im | “\ A), —2),| 972 \ ie | a j 55 Receiver wt. 1 1b.¥° Chapco Scientific Instruments are sold direct at Rock Bottom Prices Chapco Scientific Instruments, apparatus, material and for the scientist, instructor, experimenter, chemist, turist, botanist and physicist are used and endorsed by the Science Departments of thousands of American Schools, Col- — and Universities. Uustrated eee” ed on nongent—oe ietn Write for y— CHICAGO APPARATUS $ co” 36 S. Clinton St., CHICAGO, ILL, Electrical Testing Laboratories, Inc. Electrical Department Tests and investigations of electrical instruments, apparatus and materials. Inspec- tion of electrical material and apparatus at factories. Tests and imvestigations made anywhere. Photometrical Department Photometrical tests of all forms of commercial illuminants. Illumination tests made anywhere indoors or outdoors. General Testing Department Mechanical tests. Chemical tests. Coal and ash analyzed. Paper tested. Tensile, compression and torsion tests of structural and engineering materials. 80th Street. and east End Avenue RK, N. Y.

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POPULAR SCIENCE MON THLY AND WORLD ’*S ADVANCE 117

= , | i ” Multi-Audi-Fone The new wonder in the wireless world. It increases the Audibilitv 1.500 Times

areyoutrom MISSOURI 2 ten read thee LETTERS. F. B. Chambers & Co., Wireless Engineers, 2046 Arch St., Philadelphia, Pa., it “On Tuesday evening we gave @ demonstration of the Multi-Audi-Fone, to about 300 men; Technical and WIIte® = experimenters. os ion was held, is about 75 by 150 feet, and the signals from all stations 1 = | ge A Ww over the hall; and the louder ones could be heard in another room—bach of og “tall: Even the Amateurs came in “howling,” and the aerial used was only 3 wires, and about 40 feet high. tad e “ Glenn Sabin & Co., Wireless Engineers, of Northampton, Mass., write: ;“°,,»"° strated your Multi-Audi-Fone, to a number of experimenters and the results were surprisingly satisfactory. “We have picked up, stations with a single Multi-Audi-Fone, coupled to a single Audion, which we have beea ' unable to get with a double Audion.” “For getting Arlington time there is nothing that can touch it, “On our aerial we can pick up fellows fifty and sixty miles away operating on half and three-quarter inch spark coils, which is excellent work to say the least and proves without a doubt that the Multi-Audi-Fone-is an Amplifier that cannot be beaten.”

WE GUARANTEE the Multi-Audi-Fone for THREE YEARS. With fair treatment it ought to last one hundred years. a | Oo that the Multi-Audi-Fone works equally well REMEMBER =. —_—- — — — and will TEN CENTS THESE FACTS — Ceiving Set, and that it will not cost you mae += A MONTH Pe I I 5 5's 04 05.00000dee0nerebensans Our regular orders have already increased to such an extent that we are now compelled to. withdraw our ten-day trial offer. Everybody will EVENTUALLY buy a Multi-Audi-Fone. Why don’t you buy yours now and GET THE PLEASURE OUT OF IT? and |

Multum in Parvo Receiver, including Crystaloi Detector and Buzzer..............$20.00 If you prefer to use your own Detector and not buy the Crystaloi and Buzzer...... 15.00 Multi-Audi-Fone, including our specially wound Head Set .............sceeeeeee 30,00 THE CHRISTMAS PRESENT OF ALL CHRISTMAS PRESENTS, our complete Wireless Set See e rece r cece c cece vecsees « $45.00 or $50.00 Send for circular today ¥ LT 275 Morris Ave-» Ask your dealer to-morrow ? r WE Elizabeth, N. I. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE a a SAFE and BRIGHT = j in garage, barn, cellar, closet; in camp; on the motor boat; for the dark country road or any other situation where a lantern, lamp or candle is used, besides many places when an open flame would mean fire, explosion and disaster, The MESCOLITE consists of a japanned metal container with cover, fibre with battery contacts, polished metal reflector, clear glass lens, miniature ba lamp, lens cap or rim with three bayonet catches, a non-detachable bail = handle large enough to allow the arm to go through it, and a RED SEAL D Ty Battery or a special two cell dry battery. It is the simplest battery lantern made. Battery cannot be inserted in the container in any other way than the RIGHT WAY. The Red Seal Battery will give about twenty-five hours of continuous service and from forty to fifty hours of intermittent service. Always use the RED SEAL Dry Battery in prefer. ence to any other, It does not deteriorate when not in use. If the RED SEAL Dry Rat. tery cannot be had any other standard size dry cell can be used, The “Special” two cell dry battery will give approximately 60 hours of continous and 120 hours of intermittent service, If your dealer cannot supply you we postpaid on receipt of price. No. 5343—MESCOLITE, complete No. 5344—MESCOLITE, complete with RED SEAL Dry: Battery, with “Special” two cell dry Yo Volt 1aMP...ccccceceeeee $1.50 battery, 2.8 voit lamp........$1.75 nae (Itustration shows contalner with cover off and battery partly Inserted) Send for Our wer No. 4 of Wireless Telegraphy — _ al ty Oo Oe rary he You should have it even if only su- 248 pages, with over 1,100 illustrations, perficially interested. Around about and describes in plain, clear language you every day you read of some mar- all about Bells, Push Buttons, Bat- velous occurrence in which wireless teries, Telephone and Telegraph Ma- played a distinguished part. li may a. Electric Toys, Burglar and not be entirely clear to you. Tie Fire Alarm Contrivances, Electric Manual will explain it. To the Call Bells, Electric Alarm Clocks, student of Wireless Telegraphy, Medical __ Batteries, Motor Boat the Manual contains much that Horns, Electrically Heated Appa- is indispensable to a proper un- ratus, Battery Connectors, Switches, derstanding of the art. A good Battery Gauges, Wireless Tele- portion of this is now published graph Instruments, Ignition Sup- for the first time—and consists plies, etc. of formulas, tables, diagrams, Federal regulations, codes, There exist a thousand and one diagrammatic instruction for ways where electrical devices installing, maintaining and may be used, and to know operating wireless stations, what Is best for your purpose together with a complete you need this catalog. >> list of up-to-date wireless instruments and accessories. The Manual contains 120 pages, fully iMlustrated on high-grade paper stock with a two-color cover. VE We ask ten cents ($.10) for It—give you a coupon. receipt iT MEANS MONEY SA D TO You 31.00 . > + eee on any order amounting to One Dollar to have our Manual and our Catalog when you want to buy, MANHATTAN ELECTRICAL SUPPLY CO. NEW YORE: CAGO ST.LOUIS: SAN FRANCI 17 Park Place aa Ss. 5th Avenue 1106 Pine Street 604 Missoe txcest O on E a ft " - d et E vd CATA LOG IS THE EXPERIMENTER’S REFERENCE BOOK This great catalog mailed to any one upon receipt of 6c. in stamps Are You Building Something ? Our No. 6 CATALOG shows several hundred parts and sets of materials for building your own apparatus at home which have never before been listed. We do all the difficult ‘onk in our factory and then you put them together. We have JUST WHAT YOU HAVE BEEN LOOKING FOR. This Big Catalog Contains Complete description and prices of the latest Electrical and Experimental Apparatus—Storage Batteries, Rectifiers, Transformers, duction Coils, Wireless Apparatus, Lamps, Fi THE AMCO NAVY TYPE RECEIVING TRANSFORMER th. ee Mg, gg Represents the latest advances made to wards the ideal tuner and embodies the great- Mote T 1 hs, Telephones, Electrical Sup. est degree of perfection yet obtained. No greater value can be secured where ac- 0} —r wr “a elep 1 Darts for belle curate selectivity, sensitivenessand finish are desirable. The illustration shown here- Dlies, el Aerop anes REE ith o h with cannot possibly do justice to the instrument itself. The primary winding is your own apparatus. Tel w : “*elling nor d in a cabinet, the sides and top of which are polished hard rubber. Two15 ® Treatise on Wireless Telegraphy, J point switches are ted on the front. One switch controls the primary in groups to put up an aerial, connect apparatus, a of several turns and the other controls one turn ata time. The entire variation of with a Call list and Wiring Diagrams. = the primary is thus secured by the rotary motion of two knurled knobs rather than stamps will bring you this wonderful book. the movement of a slider, and — be varied from 1 to 225 turns in steps of one best catalog of wireless apparatus, etc., published. turn atatime. The d to long wave lengths. The secondary is wound with green 2 silk covered wire. The ends are HARD RUBBER, turned and pgrtenes. Secondary variation is secured by a 12-point switch which makes it possible to secure a very fineadjustment. PRICE ‘ONLY $15 ADAMS-MORGAN CO., 12 ALVIN PLACE, UPPER MONTCLAIR, N. J. When writing to Advertisers please mention Popular Science Monthly and World’s Advance. |

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE TheRise of anWho Hard work and low pay are for the man who thinks he ~ “hasn’t a chance.” for a better job—and gets it. Only a few years ago the man whose rise we picture here was working 12 hours a day for 7 days a week. But he made up his mind to train himself for something better. He marked and mailed just such a coupon as you see below. He studied at home. But the ambitious man trains himself His earnings increased. He was made Foreman. And now heis Chief Engineer, ‘. This man had no advantages that you His education was poor. His spare time was limited. And he lived a thousand miles from Scranton. with the help of the I.C.S. he has “made YOU can do the same in the line of work you like best. and write and really want to make some- thing of yourself, the I-C.S. can help you. Mark and mail the attached coupon. don’t have. good.” It won’t obli- gate you in the least — and the LC.S. will show you how you too can rise to a high- salaried posi- tion through their simple and easy system of home instruction. itl od But If you can read PRR Rr eerie: tee coger ore ype es Wouldnt Stay Down Now Chief Engineer Made Foreman Studies at Home Take the First Step Mark and Mail the Coupon NOW INTERNATIONAL CORRESPONDENCE SCHOOLS Box 1102R Scranton, Pa. Please explain, without further obligation on my part, how I can qualify for the position before which I have marked X, Electric Lighting Electric Railways Electrician Dynamo Foreman Wireman ae Engineer Telephone Expert Surveyor culture Poultry Rai3ing Automobile Running Electrical Engineering Electric Car Running Mechanical Engineer Mechanical Draftsman Shop Foreman Concrete Construction Architect Contracting and Build’g Architectural Draftsman General Illustrating Chemist Advertising Man Civil Service Exams, Salesmanship Name. Toward a St. and No Good Job Oh : TOD AY Present Occupation = Marks the Coupon —= SSSRSS Sea sShoowe———— When writing to Advertisers please mention Popular Science Monthly and -“World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE A Guaranteed $8.00 NOW READY! | Battery for f.o.b. Newark, N. J. * (6 volts—60 Ampere hour capacity) Our FREE books This is a standard GLB battery— has thick a and thick separators Fj bi W to i life—guaranteed full aca emielea ela Ignteen Ways ani to Make Money Wireless Telegraphy and : ® and the New Book Catalog giving prices Experimental Work and descriptions of hundreds of Remittance must accompany order to obtain above price. We also manufacture . a oer ee Electrical and our prices. a one Mechanical Books tl h . Send for them JEAD BATTERIES COMPANY k J New York velangd NEWARKNJ. —petreie “M® Philadelphia Established 1912 Popular Science Monthly 243 Fourth Avenue New York | Light when you need it, where you need it Indoors and outdoors, along dark hallways, poorly EAL) lighted streets, you will find a GOLD MEDAL FLASHLIGHT indispensable. ‘‘Franco” flashlights received the highest award at the ee. Exposition and are now everywhere recognized as the finest flashlights produced. ade in many different styles and sizes and sell at very reasonable prices, Go gg hh ng cca dealer and pick out. the flashlight you like. Insist on the genuine “Gold- Medal’’ fiashlight—see that it has the FRANCO trade-mark on case and battery. Write us for an interesting catalog, No. 15. It’s free. INTERSTATE ELECTRIC NOVELTY CO., ? NéW'vonk Chicago San Francisco Toronto Ww os é - ws —_— Oko Sa uz ! sccurvonuenuauaucauggsangenerGayanaayaeyenQEGayQ4qEUEEHEESEEAURUAUUQUEAUSENOUKANOUOAOUOAUOUSCUOUOECOUONOONOUOOUGUOUONOECOUOENONOEOOUONEOUOAUOUOOUUUOEOUOOUOEOOOOOOUUOUOEUOUOLOTOOUCUOUOE ENE | When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 121 oc UFPENEEDUUNESUOUECOUUUUOUEUOUUCONUEUOUEEOOENDOUUOUOUGUSOUOUOGUOOUUAHOOUSUSAUSEOOGEOOOCOOUCUOUOUOOUOUOUNOOOUOOOGCUONUOUOUCOONUOOOCOUOOUCOMUOUONUROAUOOOUONUDOEUUOCUEOOUOUOCCTOUUUOATEO ETON STE LULLLLLLLL LULL LLU LLL LLU EOL LLLALOU ALLELE LULLED MURDOCK — REGULAR WIRELESS— 2000 ohm 3000 ohm Set with Set with Coronet Coronet Band Band $4.50 $5.50 CORONET BAND RECEIVERS — THEY ‘‘BRING IN” the signals with the sensitive precision of the most expen- sive *phones. They work well, look well, wear well, and cost less than half what you might pay for less sen- sitive instruments. GUARANTEE We guarantee that these re- ceivers will prove more sen- sitive than any obtainable anywhere at the price. We will allow fourteen days for trial and will refund pur- chase price at once if the *phones are returned as un- satisfactory. Prompt shipment of orders is a prominent part of the MURDOCK policy of service to customers Our catalog is free to those interested in really good 40 CARTER STREET apparatus WM. J. MURDOCK CO. CHELSEA, MASS. 680 Howard Street, San Francisco, Cal. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE De Forest Audion Bulbs | De Forest Instruments — The Ideal Combination The Bulletin of the U. S. Bureau of Standards, Vol. 6, No. 4, Page 540, states that the DE FOREST AUDION DETECTOR is fully 50 per cent. MORE SENSITIVE than ANY other known form of detector. NO HIGHER AUTHORITY could be quoted. Further than this—ASK ANY USER. The cut illustrates the popular and Type R.JS De Forest Audion Detector efficient Type RJ5 De Forest Audion Detector. It remains in adjustment ALWAYS, and is guaranteed to be MORE EFFICIENT, and MORE RE- LIABLE than ANY OTHER detector ever offered for private use. Price, $25. THE DE FOREST AUDION AMPLIFIER is used in connec- tion with any detector, prefer- ably a De Forest Audion De- tector, to increase the intensity of received signals from 5 to 10 times (actual, not theoretical) per step. Constant and reliable, as all other De Forest Audion Apparatus. Brings in stations otherwise inaudible, ALWAYS. «Price, $65, and worth it. Type PJ1 De Forest Audion Amplifier WARNING Vacuum Bulbs, having a filament and two electrodes, as well as a number of other types, are protected tunder a large number of BASIC PATENTS, issued to Dr. Lee de Forest, and owned or controlled by this company. All infringers will be prosecuted to the full extent of the law. DE FOREST AUDION APPARATUS is sold by all the large reliable wire- less supply houses and is carried in stock by most of them. ORDER FROM YOUR REGULAR DEALER, or from us if you prefer. Bulletins giving complete descriptions sent if you enclose stamp De Forest Radio Telephone & Telegraph Co. 101 Park Avenue, New York, N. Y. When writing to Advertisers please mention Popular Science Monthly and World’s Advance. rT -_*

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE —__—-~~_ affected by near By-Stations. finest adjustment and will last CRYSTALO I—Type a 50 Postage, 10 cents ———————— : SSS rcs, CRYSTALOL "y= A PERMANENT WIRELESS DETECTOR 4: THAT HAS MADE A WONDERFUL RECORD The CRYSTALOI DETECTOR will do for you ex- actly what you would have a detector do. It will put you in touch with the Distant Stations. It is not cared for. We guarantee every instrument to be and do everything we claim for it. . . thousands that are using them—they are all for us. DIMENSIONS 4” x 3%”. describing our complete line of Receiving Apparatus can be had for five cents in stamps. ceiving Apparatus and our products are of the highest grade obtainable. EUGENE T. TURNEY CO., Inc. It is capable of the a life time if properly Ask any one of the PRICE, $6.00 Mailing Weight, One Pound. OUR NEW MINIATURE WIRELESS CATALOG REMEMBER WE ARE SPECIALISTS in wireless Re- 2595 THIRD AVENUE, NEW YORK CITY Sctentific Adventures.” “The Electrical Experimenter” he big electrical Magazine for those who dabble in electricity and Wireless. Chuck full of experiments. Intensely interesting. Monthly prizes of $5.00for best experiments. Amateur Electrics, Wireless News, Latest Patents. 100 articles, 100 to 150illus. Read thegreat serial : **Baron cba Wy New edend MO” issues Electrical Experimenter 935 Fulton Street, N. Yo 10¢ a copy at News-stands Patents Applied for R C 2 $20.00 A Marvel in Selectivity and Efficiency The Last Word Size 1214 x 914 x 6 inches in RADIO-APPARATUS Write for Literature orn oe — RECEIVING APPARATUS ” ra 00 a year. THE JOVE "No. 8804 Detector Holder, $1.00 { At Dealers or Direct From J. H. BUNNELL & CO DETECTOR HOLDER The Simplest, Handiest, and most perfect Crystal Detector Holder yet produced. Holds Crystals of different forms and sizes without any clampscrews. Holds Crystals of different minerals at same time—change of contact from one to the other may be made instantly and a sensitive point quickly found, the correct pressure held constantly, all without using a single screw or nut. BEAUTIFULLY DESIGNED AND HANDSOMELY FINISHED Have You a Copy of Our No. 36W Catalog; if Not, Write NOW ELECTRICAL *) mANuFacTuRERS 32 Park Place, *i8x*7 New York When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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124 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

Never Mind How STRONG You are— What d’ye KNOW?

Today it’s a battle of wits—and brains win. Muscle and brawn don’t count so much as they used to. The great question. now is “What d’ye KNOW ?”—it draws the line between defeat and victory—between you and the Boss. What do YOU Know? Are YOU so expert that you can “make good” as fore- man or superintendent? If not, the Inter- national Correspondence Schools can show you how you CAN hold down a good job. For more than 23 years the I.C.S. have been showing men how to do better work and earn bigger saiaries. They can do the same for YOU. No matter where you live, what hours you work, or how limited your education—if you can read and write—the 1.C.S. can train you for a more important and better-paying position. Mark and mail the attached coupon—it won’t obligate you in the least—and the 1.C.S. will show you how you can acquire this salary-raising ability right in your own home, during your spare time. Mark the Coupon—NOW

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as THE S. & K. ELECTRIC & MFG. CO. <com 104 Second Place Brooklyn, N. Y¥.

Receiving Set WIRELESS

Set exactly as 1 $2 © justrated. This ohm double cord and headband for 48 will receive 500 eo Send 2c stamp for Bulletin “G. RUTHTON ELECT. C0. 35 Frankfort St, N.Y

Y% PRICE—to Introduce ]) To prove to you that our dazzling blue-white ly MEXICAN DIAMOND La ‘< exactly resembles the finest genuine South Af- ae “rican Gem, with same dazzling rainbow-hued

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reer ERP SE 8! its _— se 2=> bal _ WP POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 125 50-75 ft. ariable Circuit Set. Mage “ps 2000 - 15000 Meters. Price’ $75.00. ‘Other Types $35.00 and $50.00. Electric Exchange Bldg. Have you heard Germany? Honolulu? Tucker- ton? Arlington talking by wireless phone to Paris? The most astounding results due to new Audion circuits can be obtained from this variable circuit set for Audion attachment Four of the latest Audion circuits can be produced, attached to a standard Audion, and communications such as the above heard on antennae as low as Special sets for schools and universities. UNIVERSITY APPARATUS CO. New York, N. Y. *12.50 Marble Base RUNS STEADY Chambers Rotary Spark Gaps Gives a tone similar to a flute on 60 cycles. Our spark gap runs on 110 D.C. or A. C. and is suitable for % to 1 K. W. Motors furnished in two sizes with % inch shafts. : Full details of prices and sizes, etc., in our new illus- trated catalog. B-24 sent on receipt of 5c in stamps F.B. CHAMBERS & CO., 2046 Arch St., PHILADELPHIA, PA. How to Make Things Electrical Complete Directions for Building Over 100 Pieces of Electrical Appara- tus, Together With a Series of Elec- trical Experiments. A Workshop Manual for the student or experimenter showing the construc- tion of everything electrical, from a simple battery cell to an electric starter for a balky horse. Includes such useful household appliances as Motors, Elec- tric Toasters, Stoves, Clocks, Bell Transformers, etc. Clear, concise directions and careful drawings are features of this book that should not be overlooked. 200 pages and 184 Price $1.50 Postpaid. Book Dept., Popular Science Monthly 248 Fourth Avenue, New York City. illustrations. This Complete Efficient Wireless Receiving Set With 80 ohm double pole S receiver headband and cord Receives up to 1,500 miles This station is equipped with a two-slide loose coupler. The primary is wound with No. 26 bare wire, secondary wound with No. 30 silk covered wire and is divided off into 10 taps which are brought out on the end piece, contact being made by a phosrhor bronze rotary switch with hard rubber knurled knob, Our new, specially designed detector will not jar out and allows a much finer adjustment than possible with any other detector. fixed condenser of exact capacity, specially con- structed for this loose coupler, affords extra efficiency. An extra pair of binding posts is provided to which a variable condenser may be connected. All parts are of solid oak and mounted on a solid oak base. The set is beautifully finished throughout and is fully guaranteed in every particular. Send stamp for our big wireless catalog “W” and free code chart made of unbreakable fibre. ) e E. d ° Universal Wireless Co., "33°25" All ‘Universal’ sets are sold_ with 10 day trial privilege and money back guarantee. Prompt shipment guaranteed. NEW DETECTOR We are placing on the market a new de- tector stand especially adapted for use with galena. It is Simple of Operation and Remains Adjusted Remarkably Well Being priced at only $1.25 it is within the reach of all. Galena crystals, each one tested, and exceptionally sensitive, 25 cents each. Our bulletin illustrating and describing the above is ready for distribution. A stamp brings it to you, together with others show- ing many good instruments. THE WIRELESS MFG. CO., Canton, O. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE wn, Neyer} Big Money in Electricity The electrical industries offer wonderful opportunities for boys with a liking for electricity. ‘The salaries paid to trained men are large—promotion comes rapidly, and, best of all, the profession is not overcrowded. The development of new branches from time to time (such as wireless telegraphy and telephony) promise fascinating and paying fields to those who wish to specialize. The will to do and Special Training will bring success to you. The International Correspondence Schools can help you to make you expert in electrical work. Thousands of boys have won success through I. C. S. help—YOU can do the same. Every- thing is made so clear that you can learn in your spare time no matter where you live or what you do. Take the first step toward success today by marking and mailing the coupon to the I. C. S. It costs you nothing to find out about it. Mark the Coupon—NOW INTERNATIONAL CORRESPONDENCE SCHOOLS Box 1102-B, SCRANTON, PA. Automobile Running Motor Boat Running Electrical Engineering Electric Lighting Electric Railways Dynamo Running Telep. and Teleg. Eng. Mechanical Engineering Mechanical Drafting Shop Practice CLTTTTTT iri ti Explain, without obligation to me, how I can qualify for the position before which I mark |_|Stenog. and Typewriting Bookkeeping R. R. Accounting Good English for Everyone Civil Service Architecture Contracting & Building Structural Engineering Plumbing and Heating Civil Engineering Steam Engineering Salesmanship Mine Foreman and Supt. Advertising Chemistry Agriculture Name. Street and No. City State i Present Occupation___ NENTS MINI SHIRE NMR OR HO ENN NIRS 11 Lessons of Course In Drugless Healing FREE! Bette set absolutely free to you! ot one cent to pay now or later. To a limited number and for a short time only, are giving 11 Complete Lessons in Mechano- Therapy absolutely free. There isnocost ¥ to you at all for these 11 sm etary Butyou must act quick! This re- markable offer is strict- lylimited. As soon as @ certain number of these sets of 11 lessons have been given we shall withdraw the offer. Don’t waitaminute. Actnow. These Lessons Teach You How to Treat Headache How to Treat Catarrh How to Treat Neuralgia How to Treat Epilepsy How to Treat Constipation How to Treat Hay Fever How to Treat Indigestion How to Treat Paralysis How to Treat a Sprain How to Treat Pleurisy How to Treat Dyspepsia How to Treat Asthma How to Treat Rheumatism How to Treat Gout How to Treat Lumbago How to Treat Jaundice Why We Make This Great Offer We want the publicto know the real truth about drug- less healing. We want you to convince yourself by an actual and practical demonstration just what a marvel- ous curative force may be placed at your command. We want you to see for yourself what tremendous oppor- tunities have been opened to practitioners of Mechano- Therapy. You will see what has beendone. You will see what can be done—by you! A Diplomain Mechano- Therapy offers you a profession of dignity, prestige, in- fluence and wealth. No special training or experience needed. If you are ambitious and can read, the way to success is open to you. Take advantage of this life. time opportunity. Also Free! $15.00 Set of Fight Anatomical Charts chart $034x22 inches, lithographed in many colors, sneact 70 diagrammed ed illustrations of diff Ms erent 0: is and parts of the anatomy. $15.00 set of charts. Now also free for a limited time only. New Illustrated Book on Drugless Healing FREE Thousands of Mechano-Therapists throughout the United States are making a big success. Let us tell you about them. Let us Wie ve how you can easily make to $500 per month and more. rite while this special 11 free lessons offer is open. —s free asi Coupon or your name and address on postal today, ceive, free, beautiful Colored : Anatomical » new Illus- trated Book on nm Healing = a FG GO, An OE AME CAN COL ev clear ® . 1 Dept. 42 81 W. Randolph St., —- On te Without pen or obligation, send a me free your New Illustrated Book on 81 W. Randolph Drugless Healing, Colored Anatomical Street, Y Charts and your offer of 11 Free Lessons, oo. a a Name. City ERR ag Tee ee LT State......... a) When writing to Advertisers please mention Popular Science Monthly and World’s Advance. b Agents-- ———— ae —_

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 127

OS

Winger’s Closed Core

m. Transformers af | | 14,000 VOLTS Y% K.W. $10.75 Yo K.W. 15. % K.W. 20.50 i K.W. 25.50 oe Designed for 110 volts 60 cycles. Send stamp for folders, etc. ial aia vi om 1 Winger Elec. & Wi. Co. BS Ser o?- Agents--Radio Apparatus Co: of America, Parkway Bldg, Philadelphia, Pa aa8=“sS'S|S|S=S——SSSSSSSSSSSSSSS —

Electrician’s Wiring Manual By F. F. Sengstock, Electrical Inspec- tor Chicago Board of Underwriters. When You Are On The Job Let This Book Be Your Helper. The book that thousands of Wiremen, Contractors and Electricians have been waiting for. Not merely a discussion on Code Rules, but straight talk from a man who knows the game from A to Z and gives you the benefit of his many years experience. Shows you just how to proceed so that your work will pass the most exacting inspector. Every step explained in detail, made clear by 415 careful drawings. Twenty-Seven Chapters, 410 Pages, 415 Illustrations of Sound, Practical Information, Flexible Leather Binding, Pocket Size. Price $1.50 Postpaid. Book Dept., Popular Science Monthly, 243 Fourth Avenue, New York City.

THESE RECEIVERS WILL INCREASE YOUR RECEIVING RANGE No matter what receivers you are now using, the Holtzer- Cabot Radio Receivers will increase the range. Sensitive- ness insures long receiving range, and The Harvard Wire- less Club of Harvard University by comparative tests has found our receivers are the most sensitive on the market. Write today for free catalogue 20E3 showing light weight receivers and proof of Holtzer - Cabot superiority.

101 PARK AVBNUB. 1104 UNION TRUST Siva, NEW YORK BALTIMORB

ERFECT working tclephoue. Ready for use the minute battery is attached. Shipped in handsome gift box, with full instructions. ‘‘Call up’? your playmates on your own private phone, between two houses, or from separate parts of one house. One outfit talks one way—two outfits both ways. Simple to use and will last a long time. Not an imitation, but a genuine telephone, 744 inches high, carbon grain trans- mitter, watch case receiver with flexible cord, finished in black enamel, polished wood base switch furnished FREE; works on_ one l5c dry attery. Send dollar bill or money order today--or write and learn how bo can be our agent and make mone e —big new illustrated catalog of more than 200 electrical, wireless id ii tal id 4 ts f THE ELECTRO-SET CO.” Dept. 218, Cleveland, Ohio, L-N-Building

No. 30. Tesla Magneto Electric Machine, Well made and very cf- ficient. BND ves osciccacees $1.00

K. & D. MOTORS FOR HOLIDAY TRADE ¢, Our line of battery motors and small generators is very complete. All machines are high-grade construction and designed for practical work. a ~ =n For sale by all dealers. Send for our new catalog, No. 10-A. All dealers should write for catalog and prices on this line. KENDRICK & DAVIS CO., LEBANON; ASVERSing CiveR <*

No. 36. Motor. (4 Has starting, stopping and e/ reversing switch and speed . reduction gearing. Very desirable for use with struc- tural steel toys and models. PONY oo vcs ccccccwcses $3.50

NEW HAMPSHIRE

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE If you want a sane, timely and authoritative in- terpretation of current events read TREWORLDS WORK | | sd e e o e ! a magazine that interprets history in the making. | THe Wortp’s Work will continue the compre- hensive treatment of the war that has nearly | doubled the circulation. | the inevitable changes that are coming in the - There will also be an important series forecasting | | new era after the war. | | If you are not a regular reader of TAEWORLDS WORK be sure to put it on your magazine list this year or send this coupon and one dollar for an in- | sa troductory six months’ subscription; open | PSM. only to new readers. | | THE Wortp’s WorK an THE WORLDS WORK months’ subscription to The World’s Work. Garden City, N. Y. eeeeeeeeeseesreseaneeeeeeesere eeeeeeeseeeseseeeseeeeeeeseeese When writing to Advertisers please mention Popular Scicnce Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE

We Guarantee You More Pa y Salary advanced from $800 to $2400 in SALARY — tnree years! That's what the right training did SRUDENCE GUARANTEES that you will | for Rudolph F. Koops, Dorchester, Mass., who receive an increase of fifty per cent over your Hf enrolled with the American School for a present salary within three years from the , Fs - : date of your enrollment; or, failing in this, the [course in Electrical Engineering. School guarantees to refund to you the full aaa amount paid for your course. He didn’t have to neglect his regular work, | either. We trained him at home—in his spare lime. Result—salary trebled in three years. You can win in your chosen line of work just as easily. The American School guarantees it. And it costs you nothing to find out how. How You Can Make More Money If you're really ambitious to earn more money and win advancement in the occupation of your choice, mark and mail the coupon. Then the American School will send you some mighty interesting facts regarding a guaranteed increase in salary. You'll be glad you wrote. It will be your first step out of the rut. re eg

Your Opportunity Coupon Mark the position you want and mail the coupon now

For over eighteen years this school has been preparing © <:.2tietenstsrncer “chur i men for bigger’ jobs and better pay. It has trained thousands i sage oe Draftsman "Corer PublleAee’at for success in Engineering, Business and Law. The Bf ::::tuilding Superintendent S..:Stencerapher American School will give you the training you need to § ... structural Drafteman —S.-Fire Inns Inspector make more money, no matter where you live or what you do. g vi [Hechasieal Drafemeen | 1..-Fire Ine Expert | 4 Remember—you don’t have to give up your work—we train» ..«.Steam Ensineer oo aa you at home, in your spare time. oe “eee i 4 --.-Sheet Metal Draftsman ...-College Preparatory a We also prepare for civil service examinations in all Mark and mail the coupon today—now! engineering subjects

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ail eel eee Ec ktititiiin Here is a new character that will live in American fiction— John Hampstead, railroad clerk, actor, book agent, preacher. “EJELD TO ANSWER” is a really big, emotional, American novel by Peter Clark Macfarlane. The author’s sincerity of purpose, his skill- ful handling of interesting characters and his development of dramatic climaxes cannot fail to make a deep impression on the reading public. The first chapters of “HELD TO ANSWER” will appear in the November Twentieth issue of ; ¢ C Il i 7 r’s ollier'’s | THE NATIONAL WEEKLY 416 West x3th Street, New York City ee TT When writing to Advertisers please mention Popular Science Monthly and World’s Adv ic 2 HL eI i aa |

Page 217

POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE THE NEWEST THING ‘IN FLASHLIGHTS Your Watch on One End of Your Chain. Your WATCHLITE on the Other End. - When used with our MARS- BRIGHT Battery No. 62-17 it will give a light that is really durable. This is not merely a novelty, but a useful, serviceable flashlight. $1.25 Ask Your Dealer for it. Send for Circulars Describing our Entire Line. Factory and ~—_ Branches BRIGHT STAR BATTERY CO. new vor wonrecn. SWEET’S JEWELS FOR YOUR SWEETHEART are an everlasting token of love and affection, They will keep rosy the memory: of that eventful Christmas or other occasion. Our cata logue de luxe contains many appropriate suggestions, and illustra- tions of a superior grade of perfect cut Blue White Diamonds, Watches, Jewelry and Silverware and explains how they can be obtained on OUR CREDIT TERMS 20°.’ DOWN—10'. MONTHLY You enjoy every advantage in price and quality. Guarantee certificate given witheach diamond. Full credit allowed on exchanges. Transactions strictly confidential. Write to-day for Catalogue No 47 L. W. SWEET & CO., * “New York city. oe i ssa IGN iM» ae . / RAS ee a im See Wr \ ae arar 3 4 e aS iy > « . a When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

Page 218

132 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE ual e . pon Gave en Now Start— on of the Chapters in the is A. Dorchester of Chicago—all he had was a high school educationina country town and a correspondence course in electrical engineering. At Free Book: 37, he was a draughtsman —and the ways to real success seemed closed. e He took this course, the office force was cut down—but he was retained— What is Effici ? and then his chance came. He was told to put his efficiency ideas into practice in : that establishment. So a new way is open to him at an age when most men have For whom is Effi given up new effort. Are the ways closed to you? Do you want to take a big new ency? step ahead? Do as he did—write now and find out about the How you are taught Efficiency? Course in Personal Efficiency An renege Find out what you are Prepared by Harrington Emerson actually doing with ° ° your time, Conducted by the Review of Reviews Company Most failures esd @il And it isn’t only success that this course brings you—it brings more leisure, better to guess work, health, and the happiness that comes from a calm, well-ordered mind, a good bank You use only half you account, and abundant business. The Editor of the New York Financial Bulletin got health, a man in the Middle West got courage to go into business for himself, R. F. Brune got $3000 a year more tosiends some be in profits—and worked 5 hours less each day. Whatever you want—Efficiency os is the shortest way to get it. Health culture. power, LON THE SERS ft ER And Harrington Emerson, who has taught Efficiency to so many corporations, Personal finances, has adapted it to youin 24 powerful, complete, condensed lessons. The corporation Mr. Emerson’s mee has capital, plant, men; you have brains, time, energy. Through these lessons you sage to you, will learn to make the most of your brains, time and energy with the least effort. / These principles are not thecasual ideasofMr. Emerson. They arethescientific The study of Efi- uy principles he has developed in forty years of study. He has applied them in over ciency ta es little Fa: 200 factories, railroads and other organizations. They are applied by other Efficiency time—gives you Engineers in America, England, France, Germany and other countries who much time, have learned them from Emerson. His big organization in New York (he i has 40 assistants) has taught Efficiency to steel mills and railroads, 7 Reviev | factories and publishers. sf gs Hundreds and hundreds of the biggest people have en- 0 of Reviews dorsed this course—have studied it and applied it to their 30 ing Place daily affairs. We have a book of over 300 reproductions of 0 Irving letters which we will gladly send to you, if you wish it. 7 New York if Send me free and wit out obligation on my part your book the Money Coming From?- also particulars about your Course in Efficiency, and of Emerson.” This Book—FREE 14 Chapters — In Colors — Illustrated Send for this book. It contains the answer to the ever-present question 6f “Where is the money com- ing from?” It tells you just what Efficiency is— what it has done for others—whatitcan do for you. 4 The Review of Reviews Co., 30 Irving PL, N.Y. e a y nei allies coed AR RRM When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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f RCRIPN ERR i SS eh aac en ae RC SL Se _POPULAR 8 SCIENCE MONTHLY AND WORLD’S ADVANCE BA ; Your boy should have his own magazine OUR boy needs reading that fits his understanding and is written in his own language. Like you, he has his own interests and hobbies. He is ALL BOY, and wants to read all about boyish topics and activities. Your bounden duty is to give him whole- some food to satisfy his mental hunger. Without question, the magazine to choose is THE AMERICAN BOY. 250,000 careful parents subscribe for it. 1400 Y. M. C. A. Secretaries and Public Librarians endorse it. For sixteen years it has been the leading high-class magazine for boys. THE AMERICAN BOY covers every phase of boyish interests and activity. It is a safe magazine which develops honor, courage, patriotism, love of nature, business ability and regard for fair play. It provides clean, fascinating stories. It gives first-hand knowledge of clean sports, how to make useful articles, latest inventions and dis- coveries and keeps a boy abreast of world progress. THE AMERICAN BOY is Written and edited for the red-blooded fellow, 8 to 20 years old, who has energy, loves fun and is blessed with an active, inquiring mind. Twelve Big Numbers for Only $1.00 We will send THE AMERICAN BOY a whole year for $1.00—twelve big, happy, inspiring issues—one every month. Why not subscribe for your boy NOW—in time for Christmas? 10c a copy at news-stands. THE SPRAGUE PUBLISHING CO., 351 American Building, Detroit, Mich. When writing to Advertisers please mention Popular ‘Science Monthly and World’s Advance. 133 TheAmericanf}oy . Read by 500,000 Boys

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POPULAR SCIENCE MONTHLY AND. WORLD’S ADVANOR ——— an T’S THE BEST you can do for Christmas — for your family, a relative, an employee, or a neighbor and all his family. It’s the Most and Best you can do for a home—at two dollars. _ 4 When writing to Adyertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE IVE IT TO WHOM YOU WILL, The Youth’s Companion fits every age and all the family enjoy it. Next year’s fifty-two splendid issues will prove a family fortune. It brings twice as much reading in a year and comes four times as often as the’ monthly magazines. Every line is worthy of the ideal home. INE GREAT SERIALS IN 1916, beginning with Homer N Greene’s stirring eleven-chapter adventure, “The Flag.” These serials would cost more than $10 in book form. 250 bright, short stories in addition. The Companion is fighting the battle for high- purposed reading, the sort that fascinates yet builds while it entertains. Everything in it interests the boy. The Boys’ Page, the live Adventure >. -f3 O > Serials and Short Stories, Sports, on a Games, Things to Make, and every phase of outdoor and indoor life. Cae reer a nnn em ——S— SSS Special Stories, all her own. The ————— e Girls’ Page, Suggestions for making CG é FTF’. qf S “pin money,” Receipts, and every- thing from Conduct to Crochet and & Candy Making. a Strong Editorial Page, valuable comment on important questions of a= | a the TS the day, Nature and Science, Original Humor, and the rare Stories catch & him also. Read all, from Family Page to = eg Doctor’s Corner. Home Helps, YMothe rs | Companion Receipts, the Stories, the Children’s Page to read to ———— _siittle ones, and all are hers. If you subscribe now, cutting out and sending this coupon with $2.00, you will get 1. All remaining issues for 1915 FREE. All for 2. The Companion Home Calendar. 3. The fifty-two issues for 1916. | $9.00 4. Beautiful Christmas Folder announcing your gift. Sample Copies Sent Upon Request. THE YOUTH’S COMPANION, BOSTON, MASSACHUSETTS When writing to Advertisers -iease mention Popular Science Monthly and World’s Advance.

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136 POPULAR SCIENCE MONTHLY AND WORLD'S ADVANCE e + The Typewriter Opportunity Will you let me send you this Standard Visible Type- writer—the Famous Model No. 5 OLIVER with Inbuilt Tabulator and back spacer—on FREE TRIAL? No money in advance—no_ deposit—no_ C.O.D. If you find it to be the best typewriter you ever saw and want to keep it, I will make you a price that is lower than wholesale—lower than the lowest agents’ prices and you can let the typewriter pay for itself.. I will take a little each month out of what it saves you, out of what it earns for you; just a few pennies a day is enough. With = Typewriter you will receive a full, Sta Model No. 5 oe Equipment, everything that ll LIFE GUARANTEE. : there are no American Typewriaers going to Europe just now, I can make you a wonderful price inducement. BE SURE AND SEND TODAY for free Catalog and Full Details of this Greatest of Typewriter Offers. All information absolutely free. General Manager. TYPEWRITERS DISTRIBUTING SYNDICATE 1510-20 K Wabash Ave., Chicago (232) WOULD YOU show this standard high grade, 42- wa key, fully visible typewriter to your friends and let them see wherein it excels any other $100 typewriter, if by doing this and rendering other small assistance, you could easily earn one to keep as your own? Then by post card or letter to us simply say “Mail Particulars.” WOODSTOCK TYPEWRITER CO., Box D203, Woodstock, Ill OVER 100,00 000 IN USE PB, Golden Gem PORTABLE Mostly sold fx Adding Machine J -loeed For Personal Desk or General Office |p ‘SS checks mqutal calculations ‘0 tion \ Write Sie r 10-day y tr ial Offer | - CHER, M. CO. : Es tiee St. New SVE. Agents Wanted “ Ww: buy at manufacturers’ prices when you - can buy at "ned own price? STOP, don't t buy before you have seen our cut rate prices on all makes. writer. Underwood, Olivers, ; Tbe be yeeros miers and other aslowas $10. Every one PERFECT and GUARANTEED 2 youre Write today. Don’t delay. Our free trial offer will interest you. ALL-MAKES TYPEWRITER EXCHANGE CO. _ 155 N. Clark St. Chicago, Il. T YPEWRITERS,,;:::. At 14 to 14 Manufacturers’ Prices Underwoods, Remingtons & C.Smiths, Olivers all makes. Your choice of any make ata bargain. First class condition guaranteed. 10 days’ free trial. Small payments or cash. Rent is applied on price. Write today for catalog 102 TYPEWRITER EMPORIUM, 34-36 W. Lake Street, Chicago fey SPENRITERD AT \ f lies -Subtracts § LAN Writeforit, C.E. GAERTE, President DEARBORN TYPEWRITER EXCHANGE, DEPT. 779 CHICAGO, ILLINOIS @et Boy Electrician mieten ime, Telegraph apparatus, Telephone, Bells, Alarmi,. Co *W iveloss"* Current Reverser, Bice c Haein, Be Etc. By wd ¢rical Experts so that anyone can understand it. W: Cat. All 200 Oc Ppd. J. C. DORN, 705 So. Dearborn St. Dent. 101, Chicago. IL THE AWL YOU WANT See That Reel The Aw] For All is the genuine MYERS $1.00 “Lock Stitch” Sewing Aw wl with exclusive feature. See thread reel in front of handle under ten tips. Natural tension. Sews heavy or light material, finger point, full grooved needles used to protect the thread when A. MYERS COMPANY, 6377 University Ave., Chicago, Iie Telescope 3 1-2 ft. Only $1.25 Post Paid Solar eyepiece and extra presi pg distance included. Send us $1.25 fur this sl 28 a am. — Fe of ——. at a a plains, stock, etc. S @ wonderful tel our large advertisement in May issue of The World's Ad = the the Be refunded if not satisfied. Catalogue sent for stam KIRTLAND BROS. & CO., Dept. WA, 96 Chambers sweet nitlill ——. Cards, circulars, bet Press 7P Yr ao n Fier $18, Rota: $0. Rave ae Print for others, b bi profit. 7 At easy, Eales sent. J Write 5 Ee ‘oday for catalogue of p ee * Oy Ww were: samples, It Shi ee you well, Meriden, Connecticut. THE PRESS CO. Meriden our wonderful new system of : teaching note music by mail, Violin, Guitar, Mandolin, Piano, Organ or Cornet, will give you a dandy instrument absolutely FREE and guarantee to make you a player or no charge; complete outfit FREE. Write af once. Special offer to first pupil. No obligation $LINGERLAND’S CORRESPONDENCE SCHOOL OF MUSIC, Dept. 12 Chicago, i, toyour audience, zs yet easy todo. Also THE MAGIC SHOP ‘30 N. 15% St.Phila., Pa. VENTRILOGUISN Taught Almost Anyone at Home. for particulars and proof 0. A. SMITH, con 384, 823 Bed Bigelow vee PO Hair Grows When properly nourished, Our VACUUM CAP used a few mit utes each day draws the blood to the hair roots. The blood is m ture’s nourishment and whem prop erly supplied, it promotes har growth, stops falling _ hair, dandruff disappears. Our cap is used by Physicians, and d men who know it to bé the Scientific of promoting “Hair send our Vacuum Cap on 60 free trial. Write for our on “Hair and Its Growth.” Testi monials, and application ae blanks sent sealed in a plain envelope The Modern Vacuum Cale 469 Barcray, When writing to Advertisers please mention Popular Science Monthly and World’s Advance. Growth.” We | gee.

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~~ is «er eoen Ss a rF ze Igertshs, —_—_—_—e POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE A Great Technical Library In Simple Language Out of a world-wide experience in teaching the engineering trades and professions by correspondence the International Correspondence Schools have perfected the greatest system of textbooks in existence. More than $2,000,000 has been expended in their preparation and $100,000 is spent annually to keep them up to date. Prompted by many requests for these textbooks without the correspondence instruction the publishers have issued a special edition from which the very elementary subjects and examination questions have been omitted. These volumes are now being offered for sale to the general public in lots of five or more on easy monthly payments. Choose the Books You Need Exclusive Features The 119 volumes included in this Library cover They are more profusely illustrated nearly every phase of mechanical and econ ey eee eee eee work, mining, architecture, advertising, business, They are written in a sivtplet 5 commercial law, etc. Being designed for home terms than any other tech- study, these textbooks are written in the very nical books. simplest terms so that men with only an ordinary They are used as text- education can easily understand them. And each Books, by more, th volume is indexed and cross-indexedsocompletelythat colleges and uni- any desired information can easily be located ona __versities. moment’s notice. The following is a partial list of © Theyare kept the different lines of work covered by this Library: thoroughly ‘” LTC. ." Box 1102-L ey Scranton, Pa. «” Without obligating me revised s . Civil Engineeri: Business and wu a any way you may send Concrete Engineering Chemistry thie e” me catalog and description of volumes on the subjects " before which I have placed an X. " —Civil Engineering — Business 8 —Concrete Engineering — Chemistry a —Electrical Engineering —Automobile 2” —Mechanical Engineering Architecture i —Telep. & Teleg. Engineering_Shop Practice * ® Name es Electrical Engineering Automobile date Mechanical Engineering Architecture Telep. and Teleg. Engineering | Shop Practice Just indicate on the attached coupon the subject in which you are interested and mail the coupon tous. This will not obligate you in the least but wi'l bring you a complete table of contents of the volumes on this particular subject, together with our plan of easy monthly payments. International Textbook Company Box 1102-L, Scranton, Pa. ." St.end No. a” City State ZEST TTT TTT TTT oa2e0eee220 OFF SOOSHSSHSSSSSSSSOESCSOSO®D * When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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MARCONI PUBLISHING COMPANY 454 Fourth Avenue, New York City Pays for This Cornet 2) Plated Lyrie Petty TRIAL aoe Wontilzer Free Band Catalo k-bottom, direct-from-the-man Bend Gute Aipat ds of instruments. Pay fo: or th Ld afew centsaday. Generous allowa em nee os fee elas ments, Free Trial.We supply the Us San Gore wane E RU DOLPH WURLITZER CO., Dept. i408 [ves Joys Make Hap YS See the Ives advertisement on page 104 Canine tons fe Frei with this superb triplesiiverplated Lyric Corn oys’ OwnToy Maker Tells Boy: to make a Bacay | OY Camera, Motor, Bicycle Boat, Canoe, Boom: Microscope, Water Wheel and Motor, Stilts, T: Coaster and Sail Boat, Telephone, Electric Bell, Rallvon’, Wind Mobile, Paddle Raft, Traps, Kites, postpaid. etc. All 10c, J. C. Dorn, 707 So. Dearborn St., Dept. 81, Chicago, Ill. erang, —_ Wind nd il Oh, You Skinny! Why i thin asa rail? 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Every thinking person knows that the day of Drugless Healing is here, and the masses of people everywhere are eagerly welcoming the science of restoring health by means of spinal = ment, as a natural, scientific substitute for the old out grown system of “‘dosing’’ by internal medicines. 5 LESSONS FREE To show you quickly and convincingly what Ch fs, E offer you 5 ns of our Regular Course vhet tee Eight (8) Anatomical Charts beautifully lithograpbed in lifelike ors that regularly sell for $15.00. - You can become a Doctor of Chiropractic in a surprisingly srt time by our practical, easy, — method of home All needless theory is thrown aside—our course offers 5 ae a most direct route to your University Degree of D. C. —Doetor Cotrepeactio. a. give you, right in por — home during your — ime, ju: e training you must have to succeed. pecial coieaed rates now! Write today for pew Mlustratel 64 Ban ged 4 and remarkable Free Lessons Offer, AMERICAN UN 162 N. Dearborn St., Dept. 465 Chicago, 1. When writing to Advertisers please mention Popular Science Monthly and World’s Advance. fe eee

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a eee, eon —_——- ——_ t POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE . “4 Fast Brush for the Pontes” Several Million Persons in the United States are continually using WHITING-ADAMS BRUSHES Their use insures Economy of Cost and Perfect Results Send for Illustrated Literature Manufactured by JOHN L. WHITING-J. J. ADAMS CO. BOSTON, U.S. A. Brush Manufacturers for over One Hundred Years tinge rs et aha WW CLASS PINS is x Made vert wa be meterta, jal order, any style or Write to-day wd sed catalog of 191 pps ang Special offer, either style of pins here illustrated with any equa! number of letters and figures, with one or two colors of best hard enamel. SILVER PLATE, $. 15 each, $1.50 per dozen; STERLING SILVER, $.30 each, $3.00 per dozen; GOLD cas $.35 each, $3.60 per dozens SOLID GOLD, $1.50 enaTian BROS. COs Ses BASTIAN GLOG., ROCHESTER, N.Y. ae’ 900 WEEKLY Robinson Folding Bath Tub. Big seller, Costs little, no plumbing, little water. Wei ht 15 pounds, folds into small roll, Full length Ni v; SA] baths, far better than tin tubs. Guar- anteed 10 years. $10 a day easily made. Write for free tub offer. Robinson Cabinet Mfgi Co., 1556 Factories Bidg., Toledo, ©. Have you looked over the Classified Advertising Section of this issue? If not, turn te page 10 and get acquainted with some of the live advertisers who are offering proposi- tions worthy of your consideration. now sold on for the first time re eecure powhers except from a mammoth organization saving, direct selling system_throug the middleman. money! Merely ape card Silo fate ental pk De ay po. fully prepaid. uotes special makes—tor all big a variety PF wquoose from. 4 This now 5 ; Bay, the first time, able toobtain quality such as ott specialty sto Sean give and rom «=| you can bri: Goods offers on wnn I 2000 Nowhere else can you have so book is free—write like but f 43 stores, but it is i coe one ©: res, Du an en! separate 5§) store in charge of experts. New York's Best Merchandise Brought to You merchandise The same high ise which you would get from the most exclusive sporting store is brought to you in this joey my ata big comin Although the prices yon pe re ‘ou buy from a s store ere tofore it has been to ler to get qual- necessary ity. But this book makes exorbitant Prices no longer aoe. Specialty sporting geste caves must and do make large pro! because they have heavy » all of which you must pay wher, buy from them. When you buy from us, you get the benefit of our tremendous cash ome | power and our money- : - at my we save middle- men’s profits and expenses, en you buy from us, onlyoue one small profit—you keep for yourself the mone; would otherwise go to New 1916 Book FREE of 2000 Bargains . Just off the press. Send no 3 Store, articles Free Catalog—140 pages— full of valuable information 15 SAVED siete J. Hardin Co.,, &.). tar BUY PLUMBING ona HEATING SUPPLIES DD FI UAAY TA Will Save j You 30% 4 7 Don’t pay retail prices, Full stock on hand ; for prompt shipment. Send for free catalog. y 8. W. KAROL, 800-802 South Kedzie Ave., CHICAGO ,roughi Repeating Rifles in all popular calibers, guns, 12, 16 and 20 gauges, hammer and less, about guns and ammunition. TheMARLINFIREARMSCo. Send 3 stamps postage to s9witlowSt.,New Haven, Conn. ing-in . ete., water pressure s ons heating sunplise every’ When writing to Advertisers please mention Popular Science Monthly and World’s Advance. y which

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Trade Marks and POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE Copyrights Secured] Patents or Fee Returned] Special Offer—Free Search of Patent Office Records Send us a model or sketch and description of your invention, and we will make a Free Search of the Patent Office Records to ascertain if it is patentable. If we report the invention patentable, we will guarantee to obtain a patent or return our fee, and furnish a certificate of patentability backed by a bonded contract to that effect. This Certificate of Patentability will protect the inventor and serve as proof of the invention until the case can be filed in the U.S. Patent Office, Obtaining Assistance for Inventors | » ——_——_~ Our certificate is of great assistance to inventors who require financial aid to obtain patents. Our Five Books Mailed Free (SEE COUPON BELOW) to any address. Send for these books—the finest publications ever issued for free distribution. ; How to Obtain a Patent Our illustrated eighty-page Guide Book is a book of reference for inventors, and contains 100 ical movements illustrated and described. ; Money in Patents Tells how to invent for profit, and gives history of successful inventions. ; What to Invent ’ Contains a valuable LIST OF INVENTIONS |. .. 4 WANTED and suggestions concerning profitable | _ fields of invention; also information regarding prizes |- 4 offered for inventions, among which is Prize of One Million Dollars offered for one invention, and $10,000 for others. Patents That Pay : Contains letters from our clients who have built up — enterprises founded upon patents procured y us; also endorsements from prominent inventors, manufacturers, Senators, Congressmen,Governors,etc, We Advertise Our Clients’ Inventions Free In a list of Sunday newspapers with two million circulation, in manufacturers’ journals and in the World’s Progress. Sample Copy Free. We save you time and money in securing patents. After the patent is granted we assist you TO SELL YOUR PATENT. Foreign Patents WE HAVE DIRECT AGENCIES IN ALL THE PORMIGN FATENTSN tee SREY poate TIME a in the shortest possible VICTOR BUILDING and at the LOWEST COST. Write for our Illustrated U.S. f GuideBook onForeign Patents,sent free to any address, Oe OT CIALLY ERECTED Ce ws tor OUR owe ceo” WANTED NEW IDEAS Send for LIST OF PATENT BUYERS who consult us when purchasin tents. Con- tains reques m MANUFACTURERS,; MAIL ORDER HOUSES an ROMOTERS for tents secured by us, and suggestions as to New Ideas they wish te purchase. We invite manufacturers and promoters to address our Sales partment regard- } ang the purchase or leasing of a number of meritorious patents secured by us. { REFERENCES | Second National Bank, Washington, D. C.; Union Savings Bank, Washington, D. C.; Chamber of Commerce, Washington, D.C; Pitner Gasoline Lighting Co., Chicago, Ill.; R. G. Dun & Co., Washington, D.C.; Smethport Glass Co., Smethport, Pa.; ‘The Melvin Gauge and Signal Co., Scranton, Pa.; M. Winter Lumber Co., Sheboygan, Wis.; National Savings and Trust Co., Washington, D.C, FREE COUPON! owe VICTOR J. EVANS & CO., Patent Attorneys NEW YORK OFFICES: 189-191 Broadway PHILADELPHIA OFFICES: 1429 Chestnut St. Main Offices: 760 9th St., N. W.,. WASHINGTON, D. C. GENTLEMEN: Please send me FREE OF CHARGE your FIVE Books as described above. NaME Soeececcceeccceccccccces ADDRESS... -.ccccccccccccccccccccccsccccces ‘ececueeanaee cocccccccscsee. B ase When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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| ‘POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 141 Your Inventions Get full money value. RELIABLE Book Free, Write R.S. & A. B. LACEY 628 Barrister Bldg.,Washington, D.C, Protective Patents = zr) EXPERIMENTORS — JNVENTORS Let us develop your inventions and make your working models Our well a shop and staff of experienced model builders are at your service. We carry a complete stock of gears. Ship- ment made same day order received. Send 4c in stamps for booklet Inventors’ Supplies. S, Estab 88 UNION SRODEL WORKS, ve stall lished 1882, awrerm® promptly. Strictly professional ser- No fee refund, no certificate guarantee no so-called prize or free search schemes used in our business. Inventor’s 112: page Blue Book on Patents sent on request. ROBB & ROBB, 240- 244 Southern Building, Washington, D. Cc. = = MONEY IN PATENTS Manufacturers are always looking for inventions. All patentable ideas should be protected by a patent. (By a Registered U.S. Patent Attorney.) The great majority of money making inventions are thought of by persons we will term amateur in- ventors, and nearly always are some very small or simple thing, for the reason that a large invention takes too much time and money for the average person to produce. We have inquiries from all over the country, in which manufacturers and business houses are look- ing for patents in every line of industry. Owing to these inquiries we are able to PUT INVENTORS IN DIRECT. TOUCH WITH MANUFACTURERS WHO WANT PATENTS and thereby find a ready sale for their invention, which, for results, is far more practicable than any other mode of assistance to inventors. Our books—‘‘List of Patent Buyers and Inventions Wanted” and “How We Secured Patents, Trade Marks, and Copyrights’’—which’.contain general pat- ent information are free and we are very glad to have you write for copies of them, P.H. PATTISON & CO. Registered United States Patent Attorney, treet, Washington, D. C. 905 G Model and Experimental Work Electrical and Mechanical Experimental Room -in conjunction with high grade machine shop at nominal rates. My twenty-two years’ experience at disposal of my clients. HENRY ZUHR 32-34 Frankfort St., New York City | QATENTS PATENTS THAT PROTECT AND PAY BOOKS and ADVICE, LIST FREE OF INVENTIONS WANTED Send sketch or model for search. Highest References. Results. ptness Assured, WATSON E. COLEMAN, Patent Lawyer 624 F Street, N. W. - Washington, D. C PATENTS amining “e: S, fice, Pats, Trade Marks, Conyrghts, Patent uti ation and and Selling inventions"! ptecting, Exploiting 12 McGill Bldg. WASHINGTON, for Inventors sent free upo C.L.PARKER Formerly Member_Ex- U. 8. Pate PATENT. LAW hg ee ATENTS S°&UTAY Rosi"pace Tas Send data (mod S me EE. VROOMAN © CO), 628 S20 Wash.,.D.c.2 IF YOU HAVE AN INVENTION which you wish to patent you can write fully and freely to Munn & Co. for advice in regard to the best way of obtaining protection. Please send sketches or a model of your inven- tion and a description of the device, explaining its operation. All communications are strictly confiden- tial. Our vast practice, extending over a period of seventy years, enables us in many cases to advise in regard to patent- ability without any expense to the client. Our Hand-Book on Patents is sent free on request. This explains our methods, terms, etc., in regard te Patents, Trade Marks, Foreign Patents, etc. All patents secured through us are. described without cost to the patentee in the SCIENTIFIC AMERICAN. MUNN & CO. SOLICITORS OF PATENTS 668 WOOLWORTH BLDG., NEW YORK and 625 F STREET, WASHINGTON, D.C. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE @, a VP! P| | | | P|, OF! GO) FSF) O'S; OH DAA AR AK AR AR FR AR AK AR A A Ae DA Inquiries from Manufacturers and Other Buyers of Patents Who Are Looking for Good Ideas Protected by Owen Patents Are constantly being received. Hundreds of ideas are wanted—a market exists for them today. YOURS may be one of them. Send for my free books and see for yourself ==read the requests for inventions tected by me. Many are simple. ou can help supply this demand. As soon as my clients’ rights are protected I aid in every practicable way, without charge, tO sell. Their applications are advertised free—their patentsare called to the attention of the proper prospective buyers— every necessary thingisdone. Get my booklets and see. THESE ARE FREE You will incur no obligation by writing me. A simple request will bring them to you—the finest, most reliable _ and instructive patent books published. A postal will do. 6s Successful Patents 9 __a 72 page guide book. tells how - , to proceed; describes my advan- tageous business methods; gives references, testimonials, etc. 6 ° 99__ gives hundreds of hints of inventions Stepping . Stones wanted; articles from interviews 0 noted authorities; tells the truth about prizes for inventions. 6 son 2— tells you how to sell; why some Patent Promotion inventors fail; discusses the value of your idea; how I aid my clients; manufacturing aids nished you; recent successful patents, etc. You will also be sent from time to time, as new inventions are wanted, full information concerning them. Only in thi way can you keep up to date. Write for These To-dayan{ivicecostsncthing. confidential. 1 secure patents or receive no compensation. Your work will receive my personal supervision—but my fees are no higher than others. Results Speak Loudest—But Here Are Some References | Whitehead Hosiery Mills, Burlington, N. C, Dickinson Mfg. Co., Des Moines, Iowa, 4& LARGE NUMBER OF OTHERS IN MY BOOKLETS. RICHARD B OWEN VY OW OY YY Or OW IF | Search of Records Send sketch or model of invention for free prt oe Patent Office Records and report on patentability. Vv ur ue ke ee a ee re 6 OWEN BLDG., » WASHINGTON, D.C. Inventors submitting their inventions to me are protected in a tangible manner until their applications are filed. ———t ¥ When writing to Advertisers please mention Popular Science Monthly and World’s Advance. th Ads

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 143 Wise bakdeds inn tolctste bahigch ab ed at mae ‘ch ale Me obama alcryc Remarkable FRED BOOKS, Today Complete and full information about patents, everything the inventor or manufacturer should know, has been included in these books. Never before has such an inexhaustible fund of valuable information been at the inventor’s disposal. Regard- less of the fact that the compilation of this information cost us thousands of dollars, we will send to all interested persons any or all of these books, entirely without charge or obligation. ‘Millions In Patents” This volume, 100 pages, tells the story of the romance of invention. The brain of the inventor is the magician that has made the ancient fairy tales come true. Millions have been paid for a book, fortunes have come from a toy.* Read “Millions In Patents,” and you will realize that this country and all the nations of the world are ready to enrich you beyond your wildest dreams if you can con- tribute one useful or amusing thing. “What Is a Trademark?” It is not an exaggeration to say that billions of dollars have been made out of trademarks, labels and copyrights. He who can fashion a trademark or design a label which will make a product stand out above all similar products is indisputably a genius for whose brains the world offers almost unlimited money. “Foreign Patents” A _ good invention is bought not by one country but by the world. “Foreign Patents” shows you how the inventor may be paid by other countries and other peoples, as well as by this nation, for his ideas and his inventions. It explains how we, through our representatives in the capitals of the world, maintain for your ben- efit.an endless chain of opportunities which, if you take advantage of them, will girdle the earth and make of your product an agent that may bring back to you rich rewards. “Inventions Needed” This book, 256 pages, lays before you a description of the active and profitable field of invention, t tells you the inventions the world needs today, the devices manufacturers are seeking for their business, the ideas for which the public will pay big-money. It gives great men’s ideas of the most important things needed in inventions now. Science is the key to wealth, and this key can be turned best by the inventor. This book tells you why. “How to Get Your Patent and Your Money” The man who invents needs the co-operation of the man who in- vests. This book, 182 pages, is a guide to the inventor. It de- scribes, according to the teachings of our experience and the lessons of men made rich by patents, how the inventor may secure money, the right amount of money, for the device which his brain has constructed. If you have invented something and desire to learn what it will cost you to get your patent and what you must do to find your market, read this book. “Special Bulletin of Patent Buyers” This bulletin, 52 pages, contains copies of hundreds of letters from wealthy men who are seeking to purchase patents. Next to the idea of the invention itself, the most valuable thing to the inventor is a hint of where there is a man ready to buy the invention or to finance the inventor so that his device can be readily marketed. We act as intermediary without one cent of charge, between the man who invents and the man who invests. We Secure Reliable Patents, Trade Marks, Copyrights, On SP SP a Pe ae ere Most Liberal Terms Ever Offered . i pasnenen & CO., Send Model or Sketch and description of your invention .for 130 F St., N. W., Washington, D. C. | Free Search of the United States Patents Gentlemen: Please send me, without obligation 1 : on my part, the books indicated on margin of Rejected and Difficult Cases are Our Specialty this coupon. (Write on margin of coupon, names J ] of books desired.) PARANDOLPH & COQ [rite cccccccnnnnnscnn 130 F St., N. W., Washington, D. c. ’ aa Pere rere ere eer errs smut ececcee a —. Sscxip-tsigy- nae enie- cour-edaemeenih tated dei When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR.SCIENCE MONTHLY AND WORLD’S ADVANCE THE VERY BEST THE ORIGINAL ISSUES OF THESE Grand Christmas Double Numbers A i AEN . FOR THE CHRISTMAS HOLIDAYS OF 1916 “Preserve Thy Body and Thy Soul.” with the Christmas Number of The Graphic WILL BE PUBLISHED SIMULTANEOUSLY IN EUROPE AND AMERICA ON OR ABOUT THE 22d OF NOVEMBERs Price THE LONDON GRAPHIC ............ $0.50 ILLUSTRATED LONDON NEWS .... 50 OM UT 00 BWI .ccccccct cscs scent 50 CE 50 sly y PR 3 (0 0\ Se 50 ern PEC EOMIAL, ......6..++0sene 50 BYSTANDER ..... 6600+ sone ses anne 50 BE BMMUAL, cccccccccccccscvedatie 1.00 TN 50 WHITAKER’S ALMANACK—Cloth ... 1.00 WHITAKER’S ALMANACK—Paper .. .50 THESE CHRISTMAS NUMBERS ARE THE FINEST IN THE WORLD They should be ordered without delay, as they will be ready early and there will be NO SECOND EDITION. ORDER NOW Of all Newsdealers or THE INTERNATIONAL NEWS COMPANY, NEW YORK a When writing te Advertisers please mention Popular Science Monthly and World’s Advance. ‘ ‘D

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE \ “RED DEVIL” TOOLS IDEAL XMAS PRESENTS They are practical. They remind your “giftee” of the giver every time he uses them. That’s a long time, because “RED DEVIL” Tools last despite hard usage. In what other way con you make your gift money produce such a lasting effect? Every “RED DEVIL” tool is scientifically designed for practical work, and DOES the work with less outlay of effort, time and money than other tools. Electrician’s extra heavy 7 in. side cutting pliers, shown here, sent for $1.00 postpaid. Send for free booklet SMITH & HEMENWAY CO., Inc., 159 Chambers St. New York City UNION TOOL CHESTS Over 15 Different Styles and Sizes ain or Quartered Oak ie: Leatherette covered. Design, workmanship and material of the best. Let Us Save Your Tools and Money If dealer does not carry, we havea special offer that will interest you. You cannot afford to go without a Union. Chest guaranteed to meet your entire approval or money back. Write today—Catalog FREE. UNION TOOL CHEST WORKS 24 Railroad St., Rochester, N.Y. TOOL CASES eters teens te in a *‘Gerst- A and guaran all money. ows many sty! MierileoriSons. Mf’rs of Mechanics’ Grade Tool Canes. 6 Columbia St.. Ohio Give Him a Pair of SEARIGHT Compound Lever Mechanics’ Snips for Christmas The cutting power of these snips is three times that of the common straight snip. They are Drop Forged from Crucible Tool Steel. No. 10-12-14 elle ON tan ‘ __ a Stes; 71,10.12 8 14in. ong QE ge —— —_ Prego sts brepaid ~ BARTLETT MANUFACTURING CO. 31 East Lafayette Ave., DETROIT, MICH. / —— ee | Friction and Ratchet Feeds Friction feed moves drill to the work; ratchet feeds drill, "Ratchet thrown off automatically, top. or bottom ; no jamming. Positive, fixed feed avoids breaking drills. 99 OLS Qnake Betts nechanics No. 1005—Two speeds; 3-jaw chuck holds up to 44-inch in diameter. No. 1003—One speed; 3-jaw chuck holds up to %4-inch in diameter. B Your dealer can supply you — > CS Write us for ** “Yankee? Tool Book,” showing Bench, Chain, Breast and Hand Drills with ratchet movement, NORTH BROS. MFG. CO., Philadelphia AN 5 UTICA DROP FORGE & TOO Have You a Pair of Utica Pliers in Your Home? ‘ Did you ever stop to think of how many things you can do with a pair of Utica Pliers; how many little things come up every day that you could take care of yourself, without the aid of a skilled mechanic, and save yourself time, money and worry? How convenient it would be to step to the drawer and get a pair of pliers and do the little job yourself? The illustration shows our No. 700-7 inch, the handiest tool ever made for household use and for experimental work. Send us $1.00 and we will mail you postpaid one of these useful tools, and if you areinterested in some other kind, ask for our booklet “‘Plier Pointers.” We'll be glad to send it. L CO., 2800-2900 Whitesboro St., Utica, N.Y. en writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE NSPECTION in modern fac- tories has become so rigid that the accuracy of work- manship is measured to the thousandth of an inch, Every hiph-prade mechanic rizes his Starrett Tools because e knows they are standard throughout the world. He knows his skill aided by these instru- ments makes him an accurate workmanand that Starrett Tools are almost an insurance against idleness, formanufacturers know that the best workmen use the best tools. Starrett Tools include 2100 styles and sizes of fine instruments —steel rules, tapes, squares, levels, hack saws, calipers and dividers, microm- eters, Rages, speed indica- tors and many others, For — - lead- ini hardware Ie stores. Send for — ~ermmanon Free Cataloz No. 20 W. THE L. S. STARRETT CO. “The World’s Greatest Tool Makers’’ REO a 7 n 4 Stanley Combination Hafts No. 305 Very handy little tools, as they are well | made, strong, and fit easily in the pocket, The illustration shows same about two- fifths actual size. With each Haft, 12 tools are furnished as follows: 1 each Chisel, Reamer, Scratch Awl, Screw Driver,, Tack Puller, Belt Awl, and 6 Brad Awls assorted, All are hardened and tempered and the tips are polished. They are approximately 15¢ inches long, Price .60 Each Sint, Festage Prepaid STANLEY Rute & Levec Co. New Britain, Conn. U.S.A, ARMSTRONG RATCHET CEILING NIPPLE gp THREADER This tool threads pi Projecting a short dis. tance from the ceiling or wall, Cuts pipe 4, % and \, Manufactured by THE ARMSTRONG M’F’G..CO. 337 KNOWLTON ST. BRIDGEPORT, CONN, eee Statement of the Ownership, Management, etc., of Por ULAR SCIENCE MONTHLY AND Wortp’s ADVANCE, lished monthly at New York, N. Y.. Editor, Waldemar Kaempffert, 239 Fourth Avenue, New York, N. Y5; Managing Editor, Waldemar Kaempffert, 239 Fourth Avenue, New York, N. Y.; Business Manager, 0. B. Capen, 239 Fourth Avenue, New York, N. Y.; lisher, The Modern Publishing Company, 239 Fourth Avenue, New York, N. Y. ames and addresses of stockholders holding 1% or more of total amount: stock; O. B. Capen, 239 Fourth Avenue, New ¥ N. Y.; H. J. Fisher, 22 William Street, New Y¥ N. Y.; The Popular Science Publishing Company. 4 239 Fourth Avenue, New York, N. Y.; R. C. Wilson © 683 Springfield Avenue, Summit, N. J. Known bond holders, mortgagees and other security holders, holding 1% or more of total amount of bonds, mo or other securities: Samuel Insull, 120 West Adams Ste Chicago, . ©, Ridenour, Great ‘LI (Signed) O. B. Capen, Business Man and subscribed before me this eighth 1915. _ (Signed) Mary B. Lambkin, Public New York County. Certificate filed in, New ¥ County. (Seal) My commission expires March, 19M Sworn 18 dy of October, 4 ° When writing to Advertisers please mention Popular Science Monthly and World’s Advance. Here dent 0! work. not ple pert m those. sures ¢ ’ have n train o % get ins Gen: At all]

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i Soe Se we YY ot. } Give That Boy Who 4 POPULAR SCIENCE MONTHLY AND WORLD’S ADVANCE 147 Likes Shop Work A Set of Good Tools Here’s the best way to encourage a stu- dent or apprentice taking up machine shop work. He will be proud of one of these sets; not playthings, but the same tools all ex- rt mechanics use. The tools included are those. essential to every young mechanic. mechanics know the trade mark in- sures quality. [BS Brown & Sharpe Sets of Standard Tools are of two styles. The one shown is neatly arranged in folding leather case measuring 7 x 4%” x 1%” folded. It includes a tempered steel rule, combination square, centre gauge, centre punch and a pair each of dividers, outside cali- pers, inside calipers and her- maphrodite calipers. The other set, fitted in a wooden case, contains in addition to the above tools a very useful “‘Handbaok for Apprenticed Ma- chinists.””. Look over these * sets at the leading hardwdre store or write us for a folder. Brown & Sharpe Manfg. Co. Providence, R.I. Our free catalog of Machinists’ Tools shows a big line of microm- eters, rules, squares, scales, ver- niers, protractors, indicators, cali- pers, dividers, gauges and other tools. SMALL SET BACK Veeder Counters (Ratchet or Revolution) RESET TO ZERO BY A SINGLE TURN These counters are just as high grade as our large counters, but are lower in price. Price $4. There are Veeder counters for practically every pur- pose. Our booklet describes these uses in detail and shows various instruments. It is Interesting and free. Send for it. The word Veeder stands for tho best constructed and most accur- ate counting devices. Cyclometers, Odometers, Tachom- eters. All kinds of counters. Fine Die Castings. VEEDER MFG, CO. 44 Sargeant St., Hartford, Conn. ALF IZE When Women Suffer No. remedy gives greater relief than Anti- ‘ Kamnia (A-K) Tablets in all conditions generally known as “Women’s Aches and Ills.” One trial will satisfy any woman that she has at last found the remedy she has so long been looking for. r « ” Indigestion—Dyspepsia Are you distressed after eating? Do you have nausea when riding in the cars or on a train or boat? Take Anti-Kamnia Tablets and get instant relief. Genuine A-K Tablets bear the Kn ' At all Druggists. — e 4K monogram Yours for the asking! Contains some practical Use- ful Gift Suggestions for Christmas If you are in- terested in tools you should cer- Write for Tt! Here’s a Fine Gift tainly have KLEIN’S POCKET TOOLKIT our latest PPR OOS ae catalog. DEALERS, cially prt ha. Holiday weds, es tools make practi- cal and always Soe acceptable Christ- e ee sia NS mes gia Contains 8 Quality Tools MATHIAS KLEIN & SONS, Mfrs. ‘Canal Sta. 3, Chicago, Ill. When writing to Advertisers please mention Popular Science Monthly and World’s Advance.

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POPULAR SCIENCE. MONTHLY AND WORLD’S ADVANCE $100 6% Gold Bonds Yielding 63% st Bs ich increasing demand for ees utility securities indicates the high favor with which investments ~ of this nature are regarded. ae. Small investors, also, may take advantage of the attractive in svestment features of ‘public utility securities, by reason of this — issue Of Public Utility Gold Bonds in small denominations bearing interest at 6 per cent. per annum. MIDDLE WEST UTILITIES CO. Ten Year 6 per cent. Collateral Gold Bonds In Denominations of $100, $500 and $1000 Each : @The Middle West Utilities Company is a successful holding peal that operates, through its subsidiaries, public utility” __ Properties in twelve states serving a population estimated, a ~ Mere than 900,000, g Thesébonds are secured by pledge of mortgage beniies OFS various properties of companies owned entirely or controlled “by the Middle West Utilities Company. x Bond coupons payable without deduction of the normal Federal Income Tax Complete descriptive data gladly sent on request. No obligation. Edward P. Russell Walter S. Brewster C. L. Penistom Russell, Brewster & Co. 116 West Adams Street, Chicago 111 Broadway, New York Members: New York Stock Exchange and Chicago Stock Exchange. When writing to Advertisers please mention Popular Science Monthly and World’s Advance,

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