Popular Science Monthly 1919-01: Vol 94 Iss 1

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OWN MAKE BAND INSTRUMENTS 9 é& & War’s Stirring Tunes Interpreted by the only instruments worthy of martial airs, the resonant silver and brass of the band, are best played on Lyon & Healy band instruments, favored through three wars and fifty intervening years—used today in our Army and Navy. Learn to Play “Fighting Music”— whether you are in service or not. It’s a wonderful source of pleasure and profit, for you can turn spare time into money. Musicians are always in demand. And you can soon master your favorite musical instru- ment. ‘The most popular men in the service are those who can play. In many cases this ability means increased pay, too. Lyon & Healy Own Make Band Instruments Set a New Standard of Excellence The finish and general workmanship are the finest that can be produced by the most advanced American methods, and the material is the best that money can procure. These instruments possess flexibility, power, and timbre in an unusual degree. In smoothness of scale,. ease of blowing, and facility of playing in the extreme high and low registers they have no rivals. The Lyon & Healy unlimited guarantee ey against all defects of ma- BEE Vvanter troops, wih tevial and workmanship ek. their band parading covers the entire life of the i throug. asevaux, ; in recaptured Aiae nstrument. A thorough trial allowed. Mail coupon. Sold by Leading Dealers Everywhere Lyon & Healy EVERYTHING KNOWN IN MUSIC 52-83 Jackson Boulevard _ & GHICAGO, U.S. A. LYON & HEAL ., 52-83 Jackson Blivd., Chicago oO Own Make _ Please send ..1e complete information and [] Popular Price illustrated literature on-in’ :ruments I have in- :, — dicated with a cross(X). at I later decide to buy, Violin I am willing to invest, in all, about $ [_] saxophone [_] Mandolin Cl Guitar Pi City & State UL — Writename of any other instrument in spacetoright (_] F UNDERWOOD & UNDERWOOD A

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Popular Science Monthly VOLUME 94 January—June, 1919 Modern Publishing Company 225 West Thirty-ninth Street New York

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Copyright, 1919, by MODERN PUBLISHING COMPANY All rights reserved

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Popular Science Monthly Waldemar Kaempffert, Editor January, 1919; Vol. 94, No. 1 Twenty Cents; Two Dollars a Year Published in New York City at 225 West Thirty-ninth Street “Dry Shooting” for Airplane Gunners By Captain E. C. Crossman, U.S. A. HE Yankee airplane machine- gunner has to lead the enemy ‘plane with his aim, precisely. as the duck-shooter has to get his line of fire out ahead of the whizzing teal to inflict hits. If the airplane gunner shoots straight at the plane going past, he hits where the plane was, but is not, merely because it requires time for the bullet to go even 200 yards, and the two planes are traveling at speeds never touched by wild fowl. Wherefore the neophyte in the machine-gun game is taught first to make quick allowance, by means of his “ring sights,’’ for a plane traveling past him on a level and at right angles to the line of fire, and then later to lead correctly for the plane traveling in various directions with relation to his line of fire. Aiming Ahead of Target - The student is seated in a pivoted plane chassis which sways at the slightest movement. It is fitted with the service ring sight, by which, auto- © International Film Shooting clay pigeons is easy compared with calculating speed and direction of this model of a German battle-plane matic allowance is made to put the line of fire ahead of the enemy plane, while still aiming straight at the pilot of the other ship. By ‘aiming through the side of the rear ring, the gunner can still aim directly at the other pilot, but is really pointing the gun ahead of the other plane, just as one can do with a wind- gage sight on a military rifle. . Use of Miniature Airplanes With the students seated -behind dummy guns, the crews working the targets operate the miniature planes mounted on pedestals to simu- late full-sized planes at a distance, traveling at various angles. The student becomes accustomed to lay- ing the sight of his gun on the plane and making the allowance necessary to inflict hits. The second stage is with actual machine-guns and ball cartridge. The guns are mounted to simulate machine-gun mounts on a plane, and the plane targets are operated by a hidden and protected crew, as in the first practice. The guns, how- ever, do not hit the planes, which are stationary. Seated in a pivoted plane chassis that sways to the slight- est movement, the student aviator learns the first principles of sight- ing a machine-gun at a rapidly moving ; enemy airplane © International Film

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Popular Science Monthly Practising with real machine-guns. The guns are mounted to simulate machine-gun © Internationa) Film mounts on an airplane, and the targets are operated by a hidden and protected crew They hit a target to the right or left of the plane, the change in position of the shot group being. made, of course, by the necessary “‘lead”’ to hit a fast moving plane. The distance from the plane to various spots on the target is known and charted out; so, with the dummy plane at a given distance and “traveling” at the angle it is given by the pit screw, the position of the shot strike on the target to the right or left shows immediately whether or not a real plane would have been hit— whether the judgment and lead used was correct to hit. More advanced courses include firing from a high-speed hydroplane or sea- sled at targets in the water, and firing from planes at objects on the water to show bullet strike. How the Modern Grenadier Is Armed An ancient practice that was revived by the trench fighting of the great war HE hand grenade was used by the French as early as the sixteenth century. During the present war several types of this weapon have been evolved. There are two principal types of hand grenades in use. One type is exploded by a time-fuse, the other on striking the ground or some other resisting object. The Besozzi grenade has a time- fuse which causes the explosion of the charge of the grenade five seconds after its ignition. The free end of the fuse has a match-tip which is ignited by striking it with a ring worn on the grenade-thrower’s left hand. Within five seconds af- ter ignition, the grenade must be at a safe distance from the thrower and within the enemy’s lines. The cast-steel body of the weapon is . deeply grooved to assist in frag- mentation. The impact type of grenade is rep- resented by the pear-shaped grenade shown in the middle of the accom- panying picture. It has a firing lever, with a cam which holds up the firing needle when the lever is folded against the side of the grenade. The end of the lever is held in place by a strap which must be removed before the bomb is thrown. When the grenade leaves the hand of the thrower, the arm of the lever is swung through an arc of 180 degrees by a spring, and the cam releases the - firing pin. The ball grenade is made to explode by @ time-fuse. The fuse is enclosed in a wooden tube which forms the neck of the bomb. It is ignited by pulling out a friction pin. The soldier about to throw the grenade hooks the wrist strap of his throwing hand to the ring of the friction pin. When the grenade leaves his hand, the - friction pin is jerked out, thereby igniting the fuse, which explodes the charge, usually after five seconds. © Underwood & Underwood The two principal types of modern hand grenades, those exploded by a time-fuse and those set off by the impact of striking the ground‘or some other resisting object 14 Ja ! @2OoOoOgta2od & my

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be al = ———_—/ | January, 1919 Will this Invention Increase the Ship Propeller’s Efficiency? O increase the efficiency of the ship’s propeller, it is suggested by an in- ventor to place a smaller propeller, but with a steeper pitch, in front of the usual propeller, and on the same shaft. The smaller radius of the auxiliary screw com- pensates forthe greater pitch, reducing the resistance to the screw. The inventor of this double propeller claims that the auxiliary screw causes a better utilization of the engine’s power. The small screw placed in front of the usual propeller acts upon the water near the shaft, where the larger screw exerts but little power. He contends that the addition of the smaller screw : will not increase the burden placed upon by a we psoatl = the engine of the ship, and that, with the on the same 8ame motive force, it will add from 25 shaft, an inven- to 30 per cent. to the driving power of tor expectstoin- the propeller. pe gegen = There is no doubt that the addition of | outaddingtothe nother screw of greater pitch would in- engine’s burden crease the driving power of the propeller a great deal, but it is by no means clear how this can be produced without adding to the burden of the ship’s Paste Gavin engines, © Publishers’ Photo Service Will That Shell Hit the Mark? It Depends on the Wind F you want to hit the target with a bullet, an arrow, or even a stone, you must allow for the wind. When ar- rows were used in warfare, the air currents were tested by experienced men, who determined the “‘windage’”’ by throw- ing tufts of grass into the air and observing their drift. But that is not accurate enough for the modern artillery- man. What good is a tuft when the range of fire is five, ten, twenty miles? For the purposes of modern artillery practice, a method for testing the air currents has been evolved that is thoroughly scientific and surprisingly accurate. Small rubber balloons filled with hydrogen, and of a conspicuous red, are sent up, and their course is closely observed through the telescope of a transit instru- ment. The vertical rise of a balloon of that type under given conditions is known. The angle of deviation for different heights is ascer- tained -at intervals of a few seconds. These data are carefully recorded by the observer, and from them the angle of correction is computed—that is, the angle between the true sighting line of the gun and the line In which the gun must be pointed to hit the target. When the balloon ascends, its course is watched to learn the wind’s velocity and direction This mass of steel is to be forged into armor-plate of the best grade and used on battleships; it takes a week for such a mass to cool A Little Ingot of Steel Weighing 320,000 Pounds HE mass of steel shown above is known as a steel ingot, and its weight as it stands—or rather hangs suspended from a crane—is 320,000 pounds, or 160 tons. An ingot is the name given to the shape of the cold steel as it comes from the mold into which it was poured in a hot liquid condition when it left the steel-making furnace. Sometimes these molds are long and round, sometimes they are square, sometimes they are octagonal or fluted, and sometimes they are of the shape shown—rectangular masses several feet wide and a foot or two or more thick. It is the latter, similar to the one illustrated, which are later reheated and forged into the armor-plate, several inches thick, which is used to protect the sides of battleships. It takes a week or two for these large masses of metal to cool. The ingot proper, or that portion which is finally used to be forged down to armor- plate or other finished forg- ings, is the rectangular part. The circular part, called the head, cools last, and presses down upon the lower main mass as this cools, filling up any part of this that becomes - hollow.

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An Aid to School-Teachers “BANKS to the ingenuity of an American inventor, the school- teacher may utilize the small boy’s energy to good purpose by allowing him to elean his eraser automatically. The essential feature is an all-metal trough into which a _ galvanized wire screen fits, causing the dust to fall into the dust receptacle below every time the eraser is set down. The eraser, is held out of+ the dust, as is the crayon. The screen can be removed and the dust cleaned out as often as is necessary. As the trough is all metal, it cannot be marred by mischievous pupils. It holds fast to the walls without warp- ing. The holder, which may be easily installed in any school building, is especially suitable for fireproof structures. Back-Yard Coal Mines OAL shortage has no terrors for people throughout great areas of North Dakota, Montana, and Wyoming. They have coal mines in their back yards. The largest deposits of coal in the United States are the lignite coal- beds of the Northwest, as yet prac- tically unexploited. In western North Dakota alone the U. S. Geo- ~logical Survey estimates there are 500,000,000,000 tons. The majority of farmers either have lignite on their own farms or dig their supply from a neighbor's coal vein. Chicago’s Memorial Arch to Her Dead -Heroes MEMORIAL arch in Grant Park, ° Chicago, is Labor’s tribute to * that city’s gold-star heroes. The arch was unveiled on Labor Day, when 200,000 organized workers marched beneath it and paraded through the downtown streets. The arch is 80 feet high. It is topped by a huge golden star, and is illuminated at night by three searchlights in red, white, and . blue. On the pillars of the arch are printed in gold letters the names of _every battle in which American troops have fought. The names of Chicago soldiers and sailors who have died are placed upon the pylons of the arch. It was designed by A. N. Rebori. Popular Science Monthly To Get a Realistic Snow Effect N attractive snow-scene effect in a window can be produced with tufts of cotton strung on black thread. A striped black- and-white background makes an effective setting, and the effect is heightened by suspending the tufts and placing the threads at irregular intervals. The scheme may be used not only in windows, but: also in the . decoration of banquet rooms, stages, and other places. A Night’s Offering to Kultur HE picture below shows a num- ber of good reasons why the Germans were anxious to make peace. In the beginning the Hun used aerial bombs like these to strafe London and Paris, in the belief that indiscriminate murder of ci- vilians would hasten a German victory. But gradually the su- premacy of the air was gained by the Allies, and when a collection of bombs such as these represented. one night’s rations for one bombing squadron, Germany was forced to take her own medicine. The Allied flyers chose military objects as their marks, but the air invasion of Germany was none the less effective in calling forth the national yell of “‘Kamerad.”’ Pritish official photograph a

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et d yn ke in he at ot he . aS, ir m- the sed afe lief 1an su- 1 of one ing to lied heir of tive | of wee ae January, 1919 gems RNAS RON TNR NIN HONE ETS SNE An Envelope-Ejector for the Addressograph MARKED increase in the speed with which envelopes may be addressed by the hand addressograph is made possible by a new attachment which ejects the envelopes after they are addressed. A small guide shoots the envelopes in the en- velope box as the arm is lifted, placing them in a neat pile in the desired order. A Hillside Cellar W F. HOLT, who is develop- * ing a model ranch near Los Angeles, has constructed a combination cellar and milk- house that is proving a most effi- cient means of practical conservation. It is built in a hillside. The two rooms are ceiled, walled, and floored with concrete. The heavy doors are divided into upper and lower sections, and the upper halves may be swung out- This down. But the city forester came to ward, leaving screened openings. is done in the evening, and the interior is thoroughly chilled by the night air. In the morning they are closed. By this means, the temperature is kept so low -that ice is unnecessary for the preserva- tion of milk and butter. Bee b ae Bolstering a BrokenTree-Top \\JHEN the wind split the upper part of the trunk of a fine old poplar tree in Central Park, Los Angeles, it looked for a time as if the only remedy were to cut the tree the réscue with a discarded flag-pole, which he cleverly utilized as a splint. The pole was set securely in the ground at.the base of the tree, and heavy iron cleats were bolted around the broken part of the tree. Assoon as the bark has grown over the break the pole will be removed. Germany’s War on Pottery SESE are not, as you might think at first glance, some new kind of mine, or great bombs, but merely a large collec- tion of earthenware pots. They. were . originally manufactured for the arts. of peace, and might have posed as models for the inanimate part of the scene in 2 modern conception of Omar’s “A jug of wine, and thou, singing beside me in the wilderness.” But the Germans had to retreat, and, following their formula, “Smash every- thing you can’t take with you,” they destroyed the pottery factory, and sent the pots rolling over the fields, thus supplying the “wilderness” to go with the jugs. Then came the British salvage corps, bent on saving all possible out of war’s wreck, and took stock of the pots. The picture above shows members of this use- . ful army division sorting the whole from the broken in an attempt to clean up the place which has now been made safe for democracy—and potters. Biritieh oMleiak chiscananh Thumbs Down on the Pay-Roll ‘TRE pen is not always mightier than the sword. There were many Indian troopers in the war who bayoneted beauti- fully, but who did not know how to write their names. This hindered them very little except when they signed the pay-roll. Here we see how they did it: with thumbprints. According to the law of thumbs, no two are alike. Sa RARER INTE NEAT AAAI A British official photograph 4

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They Brave Death for a Picture Desperate chances taken by HE life of an aviator in the British Royal Flying Corps is hazardous at all times; but there is one task that he often has to perform in which the danger incurred is perhaps the greatest of all. That task is the photograph- ing of enemy positions from the air. The pilot of a camera-plane must be a man British official photograph who is not afraid to take any chance, no matter how desperate, in reas rae | order to secure A the desired LK) Jr ~ photographs. a aa Reeve rs His airplane is- f) = ‘eserqnugoe, |] OP" the finest of its CONTRO: LEVER. pilus NE /CaMEPA mt ba FR | | the flying camera-men © Underwood & Underwood Showing them how truck. This dark-room has all the necessary accessories for developing, printing, and enlarging, and is in eharge of a sergeant and five men, two of them master photog- raphers. The cameras receive a final inspection by the sergeant. In the meantime, the pilot and observer are marking on their maps the area Liz Sy “TOP PLANE type—generally a two - seater, equipped with a 160-horse- power engine. While not very speedy, this plane is easy to maneuver and very steady in the air. Three telephoto cameras are ar- ranged so that they secure a triple panoramic view of the country below. The pictures are generally taken by the observer and not by the pilot. When he wants to make an exposure, the observer looks through a glass panel between his feet, which acts as a finder. The range of the cameras is really remarkable. I have seen photographs taken from a height of fifteen thousand feet which showed many details to the naked eye. A Flight Over the German Lines There are numerous thrills to be had on a picture-taking flight. If you will draw slightly on your imagination I will take you over the German lines with a camera-plane. " Imagine that the aerodrome is somewhere on the British front in northern France, and that the camera-plane is already outside of its hangar. Attached to every squadron on active service in the Royal Flying Corps is a photographic section, which is supplied with a dark-room on a _ motor- DOTTOM ae °& PLANE- = MIDDLE COW VINDSHIELD come Ay LE — OBSERVERS nd : to be photo- graphed. This is going to be a long flight, far into the enemy’s terri- tory, and the camera - plane’s escort of ten CAMERA STAND CAMERA CAMERA SUPPORT NOI NOD NO.3 Both single-seated and double-seated camera-planes are used. In the single-seater the camera is operated by the ‘‘joy- stick”; the plates are changed by the same means. flecting mirror constitutes the finder. Both planes are armed © Kadel & Herbert Gaze upon the upper picture, and then upon the lower. . Both are photographs taken from an airplane. They show the same village before and- after bombardment CAMERA 18 A re- fast fighters are being tuned up for the trip. You must remember that the camera-plane would be a wonderful prize for the Germans. It is the duty of these fighters to see that the precious plates are brought back safely. The weather conditions for the flight are ideal. The sky is absolutely clear. Protected by Fighting. Planes It does not take the ob- server long to decide on the altitude for taking the pho- tographs. He knows, of course, that he has to fly high in order to avoid shrapnel and enemy planes on patrol. The cameras are pronounced “‘O.K.” and orders arrive from G.H.Q. (General Headquarters) to proceed at once to the desired objective. The flight commander climbs into his fighting-plane. One after another, the escort of fighters float off into the air. The last to leave the earth, the camera-plane as- cends slowly and takes its place in the ““V” formation. The flight commander leads. Behind him are four more fighters. In the center of the V is the camera-plane, and bring- ing up the rear are the fight- ing pilots. Soon the planes are over No Man’s Land and then over German ter- ritory. Don’t think for a Popular Science Monthly’

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January, 1919 moment that this group of ma- chines flies level. As the shrapnel screams skyward, they commence to swoop and dodge, never for a moment, however, losing their compact formation. The pilot of the camera-plane sees by his instruments that he is up fourteen thousand feet; but even at this height the shrapnel from below tries to search him out. Undisturbed, the planes wing their way toward their objective. It is cold at the height at which they are flying. A glance at his map tells the observer that he is almost over the territory to be photographed. Now he concentrates his attention entirely on the glass panel between his feet. The Germans Try to Head Of : the Camera-Plane Far below are several rivers and canals, gleaming in the sun like tiny silver threads. The pilot is watching the flight commander’s plane. As he looks the signal comes, as arranged, that the squadron has arrived. Throt- tling down his engine, the pilot puts the camera-plane into a quick-turning, rapid glide. Down it drops into the region where the shrapnel is bursting thick and fast. Up above, where the camera-plane has left them, the fighters circle around and around, protecting the camera-plane from attack. Arriving at the proper level, and utterly oblivious to the shrapnel, the pilot straightens the plane out on an even keel for several seconds. As he does so the observer presses a button which unwinds the shutters of the cameras. As each photograph is taken, and before he pushes the handle that inserts new plates, he writes the num- ber of the slide on the map of the terri- tory which he has just snapped. Back and forth over its objective flies the camera-plane, until the observer is satisfied that he has photographed every inch of the ground below. Then a signal to the pilot, and the big plane ascends again to the level of its escort. Once more in formation, the fliers start on their way home. Word of the evident success of the The man at the left is not a , pilot, butanobserver. When he wants to make an ex- posure he looks between his feet at a glass panel that acts as a finder Underwood & Underwood When «the prints are ready, a staff of experts reduce them to scale, determine where they overlap, and paste them together to form a photographic map © Underwood & Underwood dashing forward into the fight. The camera-plane, with its all- ‘important information, must be seen safely home. The enemy squadron separates into groups of three, in an effort to lure one or two of our fighters to attack. But the formation must not be broken, and the tempting bait must be overlooked. As soon as the photographer touches ground again, he dispatches his camera to the developing-room installed on a motor-truck BASE OF CAMERK:: 2.027% SUPPORT - STREAMLINED GASOLINE HL CONTROL LEVERD SAFETY BELT OBSERVERS SEAT : LEWIS MACHINE q GUN STAND ss sng a ih UN MOUNTE REAR. HOLDING eed Ol CAMERA 47 CARTRIDGES ON COWL SUPPORT Looking down on a camera-plane raiders has been flashed to the nearest enemy aerodrome. The result is shown when a German squadron appears with the evident intention of cutting our squadron off. There is no question of Don’t think for a moment that photograph- ing positions is as safe or as pleasant as yachting. The bullet hole tells why 19 Nearer and nearer to the Allied lines flies the squadron, and the Germans, fearful lest their prey will escape them, swoop to the attack. Four of our planes immediately detach them- selves from the convoy and engage the enemy, while the remainder of the convoy flies home with the camera- plane safely in its midst. The four planes left behind will keep the Ger- mans busy. It is not long before the remainder of the squadron breaks formation and lands safely back at our own aerodrome. Developing Photographs and Making Maps As the camera-plane comes to earth, the sergeant and his assistants dis- mount the cameras and hurry away to te developing-room on the truck. Here the pictures are developed. Mean- while the observer fills in a form, which is then sent to the sergeant to be for- warded to G.H.Q. with the finished prints. These prints, by the way, are finished in a little more than an hour after the plates are received. The moment they are ready, they are dispatched to G.H.Q., where a staff of experts reduce them to scale, determine where they overlap, and paste them together on the photographic map. This great map has to be correct to the minutest detail. In order to keep it so, several small squadrons go out during the day, watching for changes over the enemy lines. The camera-plane of this small squad- ron is only a single-seater, equipped with one camera. An _ interesting feature of this plane is that the camera is operated from the “‘joy-stick”’ (control-lever) of the plane, even the changing of the pilates is accomplished by the same means.

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Popular Science’ Monthly Yes, Santa Got Safely And with Some Delightful Dominos printed on cards are easy for little hands to manage In verse and picture this book These lucky children have a modern toy town, with street- Colored clay that doesn’t need wet- tells her the story of electricity cars, water-works, and “everything” run by electricity ting delights the budding sculptor UME M BOMB LO With the bath- tub posing as the ocean, chil- : dren get fun and ; instruction from this realistic swimming ‘toy The new velocipede is strong This thirteen-year-old is his own Santa and like a bicycle in design, with Claus: he has: built a clockwork sub- steel spokes and ball bearings marine that will actually run under water This submarine “kiddy-car’’ car- He is learning word-building When the rider mounts this ries a full magazine of happiness with blocks that can be set ‘ hobby-horse, a spring gives it and sinks nothing but dull care up on bases, sign-board fashion all the action of trot and gallop 20

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January, 1919 through the War Zone : Excuses for Christmas Giving : This pistol fires coins, and a bull’s- eye means another nickel in the bank q ‘ ae . SSN HAE HAI ~ —s SMALL COON A AHH TAWA NT AANA LATIN maa a eT 4 ; Cleanliness and art meet in this A modern version of the old bean-bag game, with soap with ineffaceable pictures small shot-bags to release the beans for the table SHARAN ARE = A nine-hole table golf course Teaching the young idea that isan improvement on the to shoot with an un- once familiar tiddledy-winks breakable all-metal bow “> Should a submarine come down the street, this chaser will go into action at once It needs the vivid imagina- tion of children to detect the resemblance between this toy vehicle and an airplane sel MULE OULOLE ELMORE. A real player-piano in miniature delights the children—when the older folks will stop playing it long enough to give them a chance. The perforated rolls are run through the machine by turning a crank, and operate on the principle of the music-box There is endless fun for a boy in this boom- erang device, which shoots a metal ring a considerable distance, and at the same time gives it a “reverse English ’”’ that causes it to return to the shooter

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Going Motoring for Gold OME now the automobile Argonauts,;who make of treasure-hunting a picnic and pay the expenses of their holiday outings with the gold they glean so easily. This is in southern California, obtained in the sand of every mountain stream, and pas day motoring parties have learned to take advantage of the oppor- tunity to pick up pin- money and let the earth yield the cost of their tours. Within twenty- five miles of Los Angeles are the mouths of many great canyons, with trout brooks comparatively rich in placer, notably the San Gabriel, Santa Anita, Topanga, Pacoi- ma, and Big Tejunga. In the last, twenty- three miles from the city and within a hundred yards of an automobile |} drive, is a favorite spot | where anyone who un- jf derstands panning can readily wash out two or three dollars’ worth in half a day, and stand a good chance of finding single nuggets worth five dollars or more; and here all summer Lewis. W. Cubbison and his family, who are residents of Los Angeles, have made almost weekly trips and more than defrayed their expenses with the proceeds. MERICAN wheat is one of our most important fighting assets. ‘‘Food will win the war.” (You’ve heard the slogan before.) Of course, meats, fats, sugar, and leguminous foods, like beans, peas, and lentils, rich in muscle- building material, are also neces- sary; but nothing can take the place of wheat as 2 staple food. If grown in cold climates, it con- tains about 10 per cent of gluten, its most valuable constituent; if grown in hot climates, as much* as 15 per cent. Now comes Luther Burbank to the fore again. After experi- ments extending over eleven years, he assures us that he has evolved a ‘“‘super- wheat” containing an unusually high per- centage of -gluten, and so sturdy that it may be grown anywhere from Labrador to Pata- gonia. Burbank’s wheat resembles the prize-winning ‘‘Mar- quis,” but has very large white, flinty kernels. te v4 a The expenses of their Sunday outing are paid with gold from the river where “color” can be Within twenty-three miles of a city and just. off the high- way, she pans three dollars’ worth of gold in half a day Popular Science Monthly Sometimes they take a tent along, and remain several days. Three members of the party do the panning, while a fourth takes care of the camp, which is supplied with fine trout from‘ the creek. Mrs. Cubbison has become an expert at getting the yellow flakes out of the sand. On the whole, they have found the canyon so pleasant and profitable that Mr. Cubbison is considering permanent location there. This place, like the others named, is in the Angeles National Forest, and open to everybody. The canyons have a large output of gold to their credit in years gone by, and big future strikes would not be surprising. Sometimes the Cubbisons pick up burros, always avail- able in these canyons, and make prospecting excursions far back in the high mountains. Burbank Steps Forward with a Super-Wheat lA “ 2 é +, Ko’. 22 Luther Burbank says this wheat will grow anywhere; its food value is high The new. wheat is an exceed- ingly early grain—the earliest of some four or five hundred varie- ties which Burbank has been grow- ing. He has tested it by com- parison with sixty-eight of the best wheats of the world, and ' finds it superior in yield, uniform- ity, and all other desirable characteristies. .It grows vigor- ously to a height of four feet on good ordinary soil, and thrives -s In almost* ‘any «but the most extreme climates. On average ~ valley soil; without special culti- « 4 vation, care, or fertilizing, it produced in the past summer 49.88 bushels an acre. Like all other wheats grown in ._ California; the new wheat is a winter wheat.” It was tried for . baking bread; and the results of the tests were highly satisfactory. The loaves ‘were of good color, texture, and: taste. A high per- centage of gluten in bread is of importance, because the food value of the bread depends upon it. Gluten has a high food value, andcontainsfrom 15to18 per cent of nitrogen in addition to carbon | hydrogen, oxygen, and sulphur.

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January, 1919 What Four Years Have Done for Flying N® one of the four types of airplane shown here was in existence at the outbreak of the present war. Army Officers knew that the flying-machine would play some part in the war—but what part? No one divined that machine- guns would be fixed in position and fired through propellers ; that speeds of 150 miles an hour would be about right for a fighter; that machines would be developed for special purposes—bombing, artillery control, fighting, etc. Four years of warfare have done more for the development ‘of the flying-machine than ten years of peace-time discussion

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Popular Science Monthly aking a Newspaper By means of raised dots and lines news of the world is conveyed Once the story of what was going on in the world had to be read to her; but now this newspaper—printed in Braille with maps which her sensitive finger-tips can read easily—brings her the latest news of the tremen- dous changes taking place in Europe The typewriter for the blind has only six keys. Used in different combinations they emboss the desired characters of the alphabet in groups of The machine that makes the forms In printing, the reading matter is from which maps are printed has = raised dots on the paper. ‘+ embossed on two thin copper plates . eight dies, which, used singly or in In this respect the mech- at a time. The paper on which combination, produce almost any anism of the machine very the #npressions are made is placed sort of embossed lines. The map closely resembles that of the in the press between the two plates it is that of the north polar region ordinary business typewriter and subjected to high pressure Vv The copper forms on the two cylinders of the printing- press must register very accurately to give clear and sharp embossing on the sheets of moist paper placed between them eee Even in the embossed newspaper, _ typographical errors will occasionally creep in. The embossed pages are read by a blind proofreader -for errors in spelling © 44 or punctuation, and corrections 5, are made by smoothing out the plates where the errors are and punching in the corrections by means of several suitable tools ue OR Gm

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January, 1919 ALenABET a i NODMERALS \ 2 8 4 5 6 7 8 9 0 WHOLE-worD but can do every from go have just $ tet fT 8: TT TS fe Sets r Sightless Readers a a ee Wuort-worp knowledge like more not people quite rather so that : ee See BER ES Ces > ALPHABET u “ x y é a é embossed on manila paper, the WHOLE-worD us very it you i and for of the ae ° ° i th bli d Part-worp and for of the with to the finger-tips of the blin (Ae eA eee Se ae eo te 08 08 08 Se es ss Se $e w, etc. a f i $ 4 ¢ ¥ ti 6a w WHor-worpd shall this which out will PART-worD gh sh tb wh ed er ou ow bec: & eee Be-e af The revised Braille alphabet, which is Wuoie-worp : in used in this newspaper for the blind, PART-WORD en in consists of a combination of six dots yt geese Oe Fn ae age tbe Ha A eee arranged in two parallel vertical rows. ee. Fr Sy Teo | Es & 63 33 The system also has special characters ; fraction line . -fumeral sign ‘ ‘ PAaRT-WoRD [ing ar HyPstzy, ere. i Pees Snows + i2- _ : : 2 -@ -e -e oe ee > ek ane uae mere AE és Bee sigh tne dn afetegh acts ae : me aad Before the sheets of manila paper are run through the press to be embossed they are sprayed with water. Because of the great strain it must bear, only paper of a very tough quality can be used The sheets of which the newspaper for the sightless is composed are as- sembled by blind workers. Each pile contains copies of one sheet, and the piles are arranged in numerical order. The workers walk - around the table, taking one sheet from each pile in proper order. Each set of sheets is then fastened together with wire staples by a special machine before the news- paper is sent out to its blind readers The dots of the Braille alphabet are punched into thin copper plates by a é machine greatly re- Pine ia’ 3 ag Turkey Be Asia : sembling a_ type- setting machine. One of the plates serves as the stamp, the other as the die in the embossing. They register per- fectly, being made by one operation hg, When the embossed sheets come from Here is a war map of the Balkan States and of Asia Minor as it appeared in the news- . the printing-press they are still wet, paper for the blind. For obvious reasons, : and they are dried on racks before the minor details of contour are omitted they are assembled in the final form

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Popular Science Monthly RED WHITE GREEN wives F Ee ee ee a 30 IP RO TAO at SN AC SLOW TURNING MAKE AND BREAK PLATE RED TAIL LIGHT) Nx) ea ee / DIRECTION POINTER PIVOTED BLACK DISK Teg WORT BN LS IESE TLE IEE LT IIS DISK OPERATING ; MORE. =~. This is an apparatus for testing the effi- ciency of motor-driven automobile horns When the driver presses a.foot-pedal, the hand points the way the car will turn sc Sinks bam For the Driver in the Car Behind OTHING except the movement of the driver’s foot is required to oper- ate the automobile direction signal recently invented by a Maine electrician and shown above. The device is auto- matic in action, being set in motion each time the car’s foot-brake is applied. It consists of an illuminated rear-end signal carrying a white pointer hand on a black background; a special foot-brake pedal; a coil of wire ‘attached to the brake mechanism to revolve a drum in the rear signal casing, operating the pointer hand and electro-magnetic buttons on each side of the pedal, which moves the pointer hand to the right or left to show the direction in which the car will turn. When not in use, the hand is swung toward the front of the car out of sight from the rear. When the brake-pedal is depressed to slow down the car, the wire attached to the brake mechan- ism operates a small spring- BECAUSE of the numerous accidents resulting to motorists by reason of failure to see embankments or curves in the road, the Automobile Club of Southern California is placing large reflecting danger signals throughout the State. They show a beam of red light the instant the head-light of an approaching automobile falls upon them. The glass over the danger signal is clear around the edge and red in the center. driven drum to turn a shaft inside the signal casing, so that the hand becomes visible from the rear. There is a switch to light the signal at night. Picking the Longest-Winded Auto Horn ‘TYPICAL of the pains taken by auto- motive engineeers to insure the most efficient design of even the smallest unit is an experiment made recently in se- lecting a motor-driven warning signal. Fourteen horns, two each of seven differ- ent makes, were packed together in a box filled with excelsior to deaden the noise. Two large wooden pulleys were arranged so that one was driven by an electric motor and transmitted power to the second pulley by a belt. On one side of the second pulley was a strip of brass, semicircular in shape, which served to ‘‘make and break”’ the circuit that oper- ated the horns. The pulleys revolved at a rate that . blew all the horns at-once seven times a minute. Each time the circuit was closed for about four seconds, approximately the average length of warning’ signal the : motorist gives. The horns were “‘tooted’’ ten hours a day. The first to give out quit in sixteen hours. One after another, they became silent until the last one quit after sixty-eight hours, or a total of 28,560 ‘‘toots.”’ © Kadel and Herbert Recently the Morristown and Erie, a small connecting road in New Jersey, has been trying out a forty- five-horsepower motor-truck with a carrying capacity of twenty-eight passengers, with good results 26

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January, 1919

You do not need a magician’s wand to turn your roadster into a touring car or a truck if it is equipped with this device lt usually takes two or more men to operate a so-called one-man automobile top; this can be managed by one An Automobile Top Operated by the Engine

Wel Roadster, Touring Car, and Truck, All in One

N idea for a mechanically operated automobile top is shown HE versatile folding-bed of the end of the nineteeth century above. It is operated by power secured from the car is beaten to a frazzle by a recent invention in the auto- =d engine, and is based on the lazy-tong principle. mobile line. Charles J. Carlson, a citizen of Montana, has . It consists of a vertical rack provided inside of the body at the contributed an invention for changing an ordinary roadster extreme rear of the car. This rack is moved up vertically out of into a touring car with baggage attachment, or into a truck. to- its compartment by means of two shafts and bevel gearing _ When the car is to be used as a roadster, the rumble seat and ost from power taken off the car engine through a meshing pinion truck body are folded up in the rear of the roadster seats. To nit set. The stop forces the lazy-tongs to extend forward until they convert the roadster into a truck, the rumble seat is left in its se- reach the wind-shield side-bars, where they are attached, the tongs folded position, but hinged side pieces and an end piece are swung al. themselves forming the framework for the top material, which in position, so as to form a box for receiving the load. To con- er- is folded up as the tongs are drawn close together before vert the roadster or truck into a touring car, the rumble seat is ox lowering the entire device into its compartment. unfolded on top of the box body. se, _ BELL_ SHAPED SCREW FOR FLOAT ed ° co re is rie Pon Ingenious Coal-Gas Motor Tank “Ss Vee -- “theiateadd N Great Britain thé development of the use of illuminat- 8 “ CAP ing gas as fuel for motor-cars has been along two re a I sop oF distinct lines: in flexible bag containers, and in compara- er- FS 9} <4 ri.eR CAP tively small tanks capable of carrying the gas under small eet | volume but at high pressure. rat ; The tendency seems to be swinging toward the small, ‘a rigid tank. The tank here illustrated is light and yet small ed in size, and is capable of withstanding a pressure of from ely one to ten thousand pounds per square inch in a tank six ‘ha i ‘eed inches in diameter. This is made possible by using two : * cast-steel ends and winding the tank in two layers of

rs a . ans spirally wound steel tape in much the same manner as oye nit ht eS eT ee guns are wound. The longitudinal strength against ice kcdaee — ter alae The footie tl rupture is secured by lengthwise wires of high tensile ray stake ae on _— - pi ont strength between pe ter the a — - the FILLING Fe ee DISCHARGE ; ich ar Sih nnn See | tal Seal the Gasoline-Tank = 278 WR. (Sema A Dustless Carburetor

AVE you ever looked at the filler cap domed caps with N no part of an automobile | of your automobile after a long trip exPanding Joints. (ARERR Nn or a tractor are surfaces so through the country? If so, you un- ERDCAP HIGH TENSILE STRENGT: highly finished as they are in doubtedly found some moist dust around the engine. Between the piston the cap. This was caused by an appar- and the cylinder wall a space no ently small leakage out of the small wider than the thickness of a vent-hole in the cap. Did you hair is left—a space that is ever figure out how much gasoline filled with a thin film of lubricat- was. wasted by this seemingly ing oil so as to produce a perfect small leakage? seal. The efficiency of the Through tests conducted at engine .depends in a - large the Armour Institute of Tech- degree on the excellence of nology, a Chicago concern the fit between the piston found that from five to and its cylinder. If the cighteen per cent of the metal should be scratched gasoline in your car is lost there is bound to be trouble. through evaporation and spill- In a traction engine it is age, and it is now marketing easy enough for dust to find a simple gasoline tank seal. its way into the carburetor The seal permits the en- and eventually into the cyl- trance of air into the gasoline- inder. tank to replace the gasoline An English firm has brought drawn out to the carburetor, out a new type of air cleaner. but ‘prevents the flow of Air is forced to pass through gasoline out of the filler cap, = are a water seal before it reaches either through spillage or This coal-gas tank for motorcycles, etc., now being used in Great the carburetor, and all dust by evaporation. Britain, is the invention of S. J. Murphy, of Laurence Gate, Ireland is strained out. 27

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© International Film i An army may lay waste a country, but it wastes nothing itself. Waen it.breaks i camp, every scrap of i material is gathered 1h up. Here soldiers are ‘ 1 collecting cll wire, boxes, and oil-cans Troops for overseas get new outfits. Their: Ha discarded equipment is carefully collected i | and sorted. Shirts, socks, and clothes are repaired and put to use again © International Film Soldiers of the Saving Line pote i he 3 “ se Se © International Film Currycom>s, buckles, blacking- brushes, scrapers, and fly-killers were among the spoils left behind when the- 76th Division went abroad. But not even an old tin can went to the rubbish heap— in army camps there isn’t any such animal. Instead, down to the last fly-swdtter, the cast- offs were picked up and listed by the station junk corps This is an engine of war, but it belongs on the saving, not the firingline. It’sa bigstraw- baler, and its business is to rebale straw on which poten- tial heroes once slept—the heroes having gone to fight and the straw being needed for mattresses for the rookies Popular Science Monthly ve : photograph ra Even on the battlefield ° the salvage work goes on. No sooner has the attack been driven home than squads are sent out to collect the equipment of those who. have fallen in the fight The track of the retreating Germans was often marked by the wreckage of villages and homes. This salvage corps man, working within sound of the guns, is sorting and tagging the pathetic debris British official photograph - © International Film “"

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uh eld * oes ren who - ight and und and bris wy Making Crippled Planes Fit Again ~——". es An airplane’s flying life, even if it escapes accidents, is only about two weeks; therefore the repair shops are bustling places Photographs © Underwood & Underwood — ida ” ———— ~ A hurry-up job on the fuselage. The repair corps’ slogan is ‘*Make ’em fit quick’’ One of the store-rooms in which spare parts are kept ready for the demands of the airplane doctors Ss A single fast dive means taking apart the engine to clean out the soot Hi ye Testing an engine salvaged from a damaged A badly crippled airplane arriving at a repair plane. The engines have to be dis- depot. The engine alone is worth at least $5000. mantled after every eighty hours of flying New machines are built from salvaged parts

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Popular Science Monthly PROPELLING HANDLE _ FRONT WHEEL STEERING ROPES This one-man tank, its inventor claims, can travel over land or The shell that smashed this tank cut a window opening : | sea, through sand or snow; the air is not included in his claims for the Tommies who turned the monster into a snug hut i} ; A One-Man Hand-Powered Tank How Are the Mighty Fallen! HE one-man tank above was recently patented by NE of the characteristics of an army is to make John Baptiste Felicetti, an Italian residing at Phila- use of the very wrecks that war causes. A bullet- Wi delphia. In outward appearance it resembles an Egyptian pierced helmet becomes a decorative flower-pot in the HT mummy-case on wheels. The shell of the tank, of bullet- back area quarters of some garden-loving soldier; a Fi proof steel, conforms to the shape of the prone body of a__ discarded canteen is the ‘‘makings’’ of a trench banjo; 1 man. On top is a hinged double door through which the a wrecked automobile forms the groundwork of a Red soldier who is to occupy the tank enters. His body rests Cross hut; and even the once mighty tank pictured here 4 upon a hammock suspended from cross supports; his feet was turned into a cozy home for Tommies after a work the pedals of the steering-gear. German shell had ended its fighting days. The mechanism for propelling the tank is rather primi- This particular tank is one of the earlier types—great, tive. On each side is a long lever with a handle on the heavy monsters that did wonders at first, but were too i front end and a spade-like pusher at the rear end. The slow-moving to escape artillery fire; a direct hit usually i man in the tank pushes the spade end into the ground, put them out of action. The shattered side of this one, i and propels the tank by pulling on the handles of the two which makes a window for the improvised dug-out, is levers. The armament consists of a machine-gun resting eloquent testimony as to what happened to tanks that ] | upon a swiveled support. couldn’t dodge and twist through the enemy’s fire. Hi The inventor claims for his vehicle that it ‘“‘can travel The Tommies might be very happy in their bullet- d over land, sea, snow, and sand, or through water and mud.” proof house, but the sight didn’t please the men How did he overlook the air? higher up. As a result, the “whippet’’ tanks were evolved— little fellows that could maneu- ver with all the agility of their name- sake, and that didn’t stay in one place long enough to give the artillery a chance at them. They quickly replaced the heavier early types for most work, and soon swarms of them were leading the attack and clearing the road for the in- fantry. Their efficiency helped to hasten the end of the war. It Nipped !ts Way through Wire Entanglements HE combined length of the wire | entanglements used in the war i] amounted to many thousands of miles. These wire protections proved to be | ij highly effective as a weapon of de- 1 fense, a sufficient reason to stimulate | the ingenuity of inventors to devise | some equally effective method of i combating and overcoming this pro- Ht | tection, without resorting to pro_onged i artillery fire. Some of the earlier contrivances were so elaborate that they were unwieldy and an easy target for machine-guns inkl sapinet ile and heavier artillery. and machine-gun One of the simpler and more satis- bullets, they cut factory devices, developed by the barbed-wire fences French, is a shield of steel, bent so as to protect the head of the wire-snipping soldier in front and on top. It is attached to the axle of two hollow wheels filled with sand to give them greater weight. The soldier using the device crawled toward the enemy’s en- tanglement in the old Indian way, pushing the shield for- ward as he progressed. When he reached the entangle- ment, he thrust his wire nippers through an opening in the front of the shield and cut the wires. The device is small, inconspicuous, and very effective. Photographs © International Film Service Protected by this mal of t ther gers cons are Pyr van star star kno by peal Har for new ‘this are nou ries. a st app ther gray in 1 was coul wit] Its new it w Do; pro bri

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one, hat let- nen vere 1eu- me- lace ince the and the y in- sten ‘this continent. Januury, 1919 why? HE stars, shining above us night after night, have changed littlesince mankind has lived on the earth. Many of the brighter ones bear names given them by the astronomers and astrolo- gers of thousands of years ago. The constellations were arranged as they are to-day when the builders of the Pyramids observed them from those vantage points. So it is a rather startling phenomenon when a new star takes its place among the well known ancient configurations. On June 8th last it was announced by Harvard that a new star had ap- peared in the eonstellation of Aquila. Harvard acts as the central bureau for sending out information about new discoveries to the astronomers of All new discoveries are reported to Harvard, and an- nounced through its list of observato- ries. On the 7th of June there was a star in the position indicated, for it appears on some photographs taken then. Indeed, it appears on a photo- graph taken at Harvard in 1888 and in many others made since. But it was a star so faint that it could not be. seen, except with a good-sized telescope. It Seemed About to Outshine Sirius On the 8th of June the new star blazed up until it was of the first magnitude. By the tenth it was almost as bright as Sirius, the Dog. Star, and for a time Promised to deprive it of the distinction of being the brightest star in the sky. ee ol a Most new stars appear in or near the Milky Way. Here we have plotted the principal new stars that have been: observed and the dates when they were seen New Stars—What Are They? A bright star suddenly flares up— Perhaps two stars collided By Ernest A. Hodgson Sirius is about four and a quarter times as bright as a first-magnitude star. The title was quickly restored to Sirius, however; for in a few hours the new star was fading, and by the night of the 13th it was just first magnitude again. There Are Many Wonder Stars Since then it has continued to fade, with slight periods of recovery every ten days or so. By the middle of Sep- tember it had become a good test of eyesight to find ‘‘Nova Aquilae,’”’ as it is called. By the time this article is published it will probably have become a telescopic star once more. But we shall not be able to tell; for by that time it will have passed, together with the other summer stars, and will be in the sky only during the day. This Nova, although it is indeed a wonder star, is only one of many. Most Novae are discovered only by means of a painstaking study of star fields, photographed night after night. They are not noticed, for they do not 31 become very bright—a large majority scarcely becoming visible to the naked eye at their maximum. Almost all the Novae, and practically all the visible ones, have appeared in that part of the sky known as the Milky Way. : Of the bright Novae, the one that has been studied most completely is that which appeared in the constella- tion of Perseus on February 22, 1901. This Nova became two and one half times as bright as a first-magnitude star within the space of a few hours. It then gradually through many oscillations of about a magnitude, and finally dying away to a faint star once more. faded, passing Getting the Ranges of a Star The distance of Nova Persei was finally computed. The method that astronomers use is, in theory, exactly the same as that followed by gunners who wish to measure the distance to a certain target. provided with two prisms, which take the light from the two ends of a certain Their range-finder is measured distance A B (page 32) in the instrument itself. The angle at A or B can be measured, and this angle, together with the distance AB, will enable them to find the distance OX. In the case of the range-finder, calcula- tions are avoided by cali- brating the instrument. In determining the dis- tance of a star, the line AB must be very long. The distance chosen for a base line .was not a mile, or a thousand miles, or even the

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Ea wee SS AS diameter of the earth; all these would ‘be. much too short. What-they do use is the axis of the éllipse traversed by the earth in its journey around the sun— a base line 186,000,000 miles long. Observations . are made six months apart, when *the earth is first on one . side and then on the other of itsorbit. Even with this enor- mous base line, the angles, determining the distance of Nova Persei, were so small as to require great care and delicate instruments to mea- sure. It-was found that the Nova was so far away that light, traveling 186,000 miles a second, would require about 300 years to reach us from the star. So, although it was seen as a Nova in 1901, it really burst out into bright- was the Nova and its giant cloud that _the whole appeared as a tiny speck, too faint to be seen except by a long exposure of the photographic plate, aided by the great light-gathering properties ‘of a large telescope. The photographs that appear on this page show what happens if we separate the various colors of light that come to us from the star, by means of a spectroscope, Popular Science Monthly spectra show that the star changeq Dark lines indicate the absence of certain colors and show that the substances which # in a state of incandescence within the — star, would produce those colors ape present in a cooler, gaseous state out. _ side the star. — color from day to day. It will be noted that the spectrum of June 10 shows more dark lines than the one of June 9. This shows that the source of light “wag: ss eee | ©, THE EARTH 300 YEARS a \ +—NEBULA A OUT n BU! e 23 ta oS ie) Pe ly °: > - * HE 1x A Coe TO THE EARTH 300 YEARS which was cool, compared with the center of the star. By July 30 the dark lines had almost disap. peared and bright bands The light direct from the new star (Nova Persei) reached us in about 300 years. That alone remained, indicating that the Nova was’ then stronger, but was still shining” through a gaseous envelope | ness about the year 1600. Photographing the Stars. A x b Probably the most Bee ohn ie teresting thing discovered tance of the about Nova Persei was dis- arth from covered by means of photo- Nova Persei was computed graphs taken six months after which went out to light up the cloudy material progressed outward for six months, traveling in that time abdéut 3,000,000,000,000 miles. Then it was reflected toward the earth by the nebulous material, and took, of course, 300 years to reach us, arriving six months after the light from the first outburst. And yet, so far away was the Nova and its giant cloud that the whole appeared as a tiny speck too faint to be seen except by long exposure of the photo- graphic plate, aided by the great light- gathering properties of a large telescope heated throughout. The in. tensity of the light, however, wasless, showing that thetem- perature as a whole by that time had fallen. This order of change in spectrum is charac. teristic of Novae in general, Several Explanations ‘was passing farther and farther it first appeared. These photographs were made by astrono- mers who carefully kept their tele- scopes pointing on the same point for hours at a stretch, following the star ‘ as it passed across our sky throughout the night. The light.from the faint star was thus able to hammer away; so to speak, for-all this time, impress- ing itself on the photographic plate. , The results showed that the Nova was apparently becom- ing surrounded with nebu- lous, cloudlike matter, which outward from the body of the star. Calculations showed that if this were being shot out from the Nova, it must be passing outward at about the speed of light. It. has been suggested that the nebulous matter might have been there all the time, but that the light from the blazing up of the star had just reached it. Sifting the Light of the Stars If we look at the diagram we shall see what was meant. The light direct from the _ star reached us in about 300 years. That which went out to light up the cloudy material pro- gressed outward for six months, traveling in that time about 3,000,000,000,000 miles. Then it was reflected toward the earth by the nebulous material, and took, of course, 300 years to reach us, arriving six months after the light direct from the outburst. And yet,.so far away which is practically alight sieve. If all” the light were, say, one shade of blue, there would be only a blue line show- ing. If all the shades of all the colors were present, we would callit whitelight, and the spectrum would be continuous -from red to violet, as it is in the rain- bow. The red light lies to the right- hand side of the photographs. These There are several explana- tions of the cause of these strange outbursts. One is that the star, as it traveled through space, ran into a mass of nebulous matter, which carsed it to glow. This explanation, while it satisfies many of the observations, is difficult to accept; for the nebulous matter would need to be very dense to cause such an increase in tempera- The spectrum of Nova Aquilae on June 9, 1918 . or. The spectrum of Nova Aquiiae on June 10, 1918 sree erm The spectrum of Nova Aquilae on July 30, 1918 These three photographs of the spectrum of Nova Aquilae, which were made by W. E. Harper, of the Dominion Astronomical Observatory, Ottawa, Canada, show how remarkably swift are the changes that take place in a new star. The straight lines and bands are produced by the glowing elements in the Nova. line or band always appears in the same relative place. The same Hence, as it disappears or becomes more intense we have unmistakable evidence of a great chemical change 32 — git. lca pet een ete Seceuek Send om = DH Tf fe eee the - pa iim. > “ac! att tte

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lines Olors, « hich, © Nn the s are 4 Olt. ‘trum ‘than that “Was” ‘ining elope | pared the dark iSap- ands ating then 1e in- yever, 2 tem- ~ that der of larac. neral, thy dlana- range ar, as into a arsed hile it ns, ig rulous dense npera: | January, 1919 ‘boilers have a diameter of 1414 nd it would need to be very poet in area to account for the short time the star remained at its maxi- mum. Another explanation is that the Nova collided. with a dark star, the collision resulting in the enormous heat which caused the star to he- ecme gaseous andexpand. It then cooled off gradually. That New Dark Star One aspect: of this theory is in- teresting to us. May not a dark star even now be approaching, and about to col- lide with our sun, causing an out- burst which would destroy the earth at once? ~-. “It may hap- pen. - Who can tell? But before it does a “new star” will appear in our sky—this dark star illumi- nated by our sun just as our moon is. This star will slowly . approach amaximum, how- ever, and other phenomena con- nected with it in 1901, in about three hundred years. would enable astronomers to predict “the end of the world.’”’ We would have ample warning years before the collision. But this collision theory does not explain the fact that the glow passes through other smaller. maxima as it This is a photograph of the nebulosity around Nova Persei, made by Yerkes Observatory. The light direct from the star reached us So, although it was seen as a Nova it really burst into brightness about the year 1600 dies away, and it has furthermore been calculated that there would have to. be about four thousand times as many dark stars as-there are bright ones to account for the number of Novae that have been seen—a difficult rather to believe. Absolutely ‘**No Insurance” So, the phe- nomena connect- ed with Novae still await a theory that will combine them all. In the mean- time, further evidence is being collected by our modern astro- nomical ‘‘ad- justers’” fromour latest - celestial “conflagration,” which, it is hoped, will en- able them to fix the responsi- bility. It may be safely stated, in any case, that everything on the dark body as well as on any dark satellite of the bright one that may have existed was a ‘total loss’ and that there was absolutely ‘‘ no insurance.” thing Transporting Huge Marine Boilers by Rail TEAMSHIPS must have boilers, and these cannot always con- veniently be built where the ships are constructed. Oncesafely stowed away in the hold of the ship, these gigantic boilers give little trouble; but to get them there safely is a different matter, especially if they have to be carried to their destina- so as to bring them within (a foot of the rails. formed the huge boiler was placed, and securely fastened to supporting blocks. When the steamer Bear, of the -tion-by rail. Some of these feet and a length of more than 11 feet. Each weighs about 91,000 pounds, and a 3,500-ton ship requires two. To transport these boilers on the regulation flat-cars is impos- sible, because, by reason of their large dimensions, they cannot pass through tunnels or under bridges. The engineering problem pre- sented in one case was solved by building a special car. The I- beams that form the longitu- dinal supports of the platform cars were curved in the middle In the cradle -thus - United States Geodetic Survey, was wrecked on the Pacific coast, many miles away from the nearest railroad line, great difficulty was experienced in’ transporting the huge boilers of the steamship after they had been salvaged. The problem was solved by making them water-tight by plugging up all the openings, rolling them into the water, and towing the floating monsters to the nearest port. There the huge boilers were transferred to railroad cars to be hauled to their destination. The proper making of these enormous boilers requires special machinery and appliances which are not always available at shipbuilding yards, and, after all, it is easier to transport a complete boiler than .a whole factory with its equipment of This is one solution of the problem of shipping large marine boilers by rail 33 specially designed machinery and its large force of trained workmen.

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aie CA inate inn i ATE DOE ESS ESET LEO E LE TOT LL LES LOA ITE ET OE gai aaa Rta Popular Science Monthly © International Film Service Those Wash-Days in Flanders © International Fil Service ‘*Here’s Where We Licked Them”’ ‘T3s husky standing by the machine is not a mechanic—he Wars are even more important to an army than to a stranger was a ‘washerwoman.” His wash-tubs were the two’ big drums behind the engine, and in them he washed mud-, blood-, cootie-coveréd shirts and trousers for Yankee soldiers. He would run his massive truck close up to the front lines, and dump the dirty uniforms into boiling water in the drums. Thus he kept the army clean and un- cootied. The rifle on the front of his car was just @ precaution in case the Germans couldn’t resist the temptation to come over to steal the Monday wash. DISCOVERY that seems des- tined to play an important part. in building up future supplies of wool and mutton has recently been announced by a Washington State sheep-rancher, Mr. Y. C. Mansfield. By mere chance he found. that sheep thmve on the Australian salt-bush, heretofore re- garded as a despised weed, of which there are literally millions of acres in some of our Northwestern States. in New York’s subway maze. Big war maps were in evi- dence everywhere on the western front. They were housed in shelters like the one shown above, wherea British Tommy seems 4 to be telling a squad of our boys just how ® and where it all happened. The map they x are looking at shows the western front as a whole, but maps similarly sheltered show -\ in great detail portions of the front, usually bi | those directly opposite the trenches. ° The quickest way to get maps is to send a photographer out with an aviator to fly over the country to be photographed. How Did It Get Here ? [F you. throw your wedding-ring into the ashes, do not be sure it is gone forever. It may come to life again, as did this one, around the neck of a po- tato. The ashes were thrown out ona field that had been tilled and cultivated for potatoes. One small, sentimental spud stuck his head through the ring, and when he grew up looked like this. Youthful Aristocracy HIS little aristocrat, who is not quite hardy enough to stand the cold winter wind, is comfortably fixed up in a limousine-sled. It has a heating and lighting apparatus within. The small owner gets in through the top. When he is comfortably seated, his indulgent parent puts down the lid, picks up the ropes, and starts. Motion Pictures Anywhere N enterprising manufacturer has developed a hand electric generator with which motion pic- tures up to eight or ten feet wide can be given. The projector illustrated uses only. slow-burning film, so that it can be used anywhere without the booth or insurance restriction. The entire outfit weighs only ninety- seven pounds. Probably the South Sea Islanders will soon be familiar with Mary Pickford. a4

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er vi- nt. ne - OW ey sa ow lly nd here turer ectric 1 pice ;wide uses hat it ut the . The inety- South \miliar January, 1919 official photograph ley line. jee Re Pes wow 4 in * "%. gong sounds. A Rival to Houdini N far-off Bagdad, herculean strength was common in those ‘ Arabian Nights” days when Aladain wandered about with his magic lamp. The name “ Bagdad”’ still holds its thrill for us, but British soldiers found the place disappointingly normal when they arrived there. One day they happened on this Arab carrying on his back a life-boat— a task for ten ordinary men. Tommy, gazing at him, almost believed him to be a magic relic of the past. When Paris Envied Pittsburgh IKE most other large cities, Paris has had its Society for the Abate- ment of the Smoke Nuisance: but cir- cumstances alter cases. Such asmall circumstance as one toot from the air- A startling danger signal has been invented for such a crossing. It stands on a corner that the cars pass, and is so connected with the track that when a car approaches the arm at the top revolves into an outstretched position and a large The signal itself is painted in startling colors, like a camouflaged ship. Danger ! \ JHERE three streets come to- gether at one place the crossing British is sure to be dangerous, particularly if traffic is heavy and there is a trol- When Huns Still Flew V HEN airplanes flew low in sup- port of infantry on the western front, there was no time for the anti- aircraft gunners to use range-finders. At any rate, the range-finders built in peace times were generally found to be useless against fast flying airplanes, and the successful aircraft hunter was he who had a quick and accurate eye for distance and speed. But a machine-gun cannot be han- dled as easily as a 12-bore, and so an inventive Tommy hit upon the idea of mounting a discarded gun wheel on a post so that it would revolve, and then lashing his machine-gun to the rim of the wheel. This done, he was able to swing his piece in any direc- tion skyward and make things warm for a low flying enemy aviator. But instances of machines being brought down by rifle or machine-gun fire were raid siren could convert every member of that society into an ardent wor- shiper of smoke; the thicker and oilier, the better they liked it. - The smoke-cloud defense, which proved so effective against submarines, was easily adapted to land, and, after trial at the front, was installed as a branch of Paris’s air defense. These smoke-producers, which freed a harmless smoke that was heavier than air or poison gas, were of modest mien. Objects that looked like concrete top-hats, inverted and scat- tered around the city in the path of any breeze, were the only apparatus used in the feat of blotting Paris from the face of France ten minutes after an alarm. © International Film not common. . It Was Caught Before It Fell AD this pole fallen and the wires been injured, hundreds of telephones on the western front would have been put out of commission. Realizing the seriousness of this, these men worked desperately to keep it up. A heavy snow-storm, followed by a freezing rain, weighed down the wires with frozen snow. The wires would have suc- ceeded in dragging down the pole, owing to its in secure foothold in the soft dirt, had not these men interfered. British official photograph

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cn: eee Seen eeEee ne ren SS ERIE EGR SE ats | Presenting the Bill to Bill As for the bloodshed, Bill, that you cannot pay for. Every drop of it is priceless. If the total loss of life had been borne by us in America, the entire population of. IIli- nois and Indiana, for example, would have been completely wiped out. The number of killed has-been estimatei at eight and a half millions. The disabled number 7,175,000, which is about equal -to the combined population of the six States of New Hampshire, Vermont, Connecticut, Rhode Island, Massachusetts, and Maine. We have tried tc bring out these facts in the map by shading certain States © ‘“‘Destruction of buildings, machinery, and farms in Belgium and France, $3,735,000,000.” the first item on the bill presented to you, Bill. wonder how you are going to pay it. would fill one hundred and ninety freight cars—a. train nearly a mile and a half long. That is the general idea we have tried to convey in the picture above, Bill—destruction on the one side, and pay- ment in a gold-laden freight train on the other Item No. 2 in the bill: “Destruction of fifteen million tons of shipping: $1,050,000,000.” That’s letting you off rather easy, Bill; for we are charging you with the value of the ships on a pre-war basis. Out of every three ships that the Allies possessed, you sank one. That ex- plains the explosions in the great fleet here pictured Popular Science Monthly That will be So much gold

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The Pigeons’ Flying Corps These fearless aviators heed neither wounds nor exhaustion until they have reached home ; in | be We ‘old —a the ure ay- her This squadron’s aerodrome was once a grocery wagon; later seventy-two flyers dwelt there in perfect safety, for it was so well painted to match the landscape that it was invisible to enemy observers f Photographs by Hdwin Levick Pencil and paper having been tied to the breast feath- ers of these airmen, they were ready for With a pigeon in a their day’s _ work cage on his back, ready to dash forth in search of. his master, who is lost My 4 If you whisper an address into a pigeon’s ear, you can’t expect him to go This balloon is inflated in such a way that it will travel a limited distance and then gently drop to there; he is only taught to earth. A message is then written and ' : fly home. Send him by attached to the pigeon balloonist, i. tae ee airplane, parachuting him who when released flies swiftly home ye down at the right spot

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Popular Science Monthly Make Your Own Christmas Tree ANTA’S stinginess in handing out real pine Christmas trees in the last few years has caused us to look on him with increasing disfavor. But if our patron saint won’t give us Christ- mas trees our inventors will make us some. Here is a man- made tree that has several added attractions which Santa’s kind doesn’t have. Mounted. on the base are a central shaft and an outside frame made up of poles which are held in place at the top by a piece of cir- cular wood. These outside poles, which are sta- tionary, have holes in them in which natural or . artificial tree is started the branches can be 5 ie A center revolves placed. The poles themselvesincline inwardly, so when the branches .are inserted this artificial tree will taper as a real tree does. On the central shaft are mount- ed several star-shaped platforms for holding angels, glittering balls, and any other decorations. This central shaft has a driving gear attached to it, When the motor 5 The central shaft of this artificial tree, with its decorations, is revolved by a motor in its base Counter stool —~ hidden beneath the store window floor The mechanism is ° Clock enaleinn They’re Ready for a Siberian Winter carefully concealed in the base. In the base there is also a motor with a pinion projecting upward which meshes with the gear. Thus when the motor is started the central shaft revolves, and so of course do the star-shaped platforms. The result is most pleas- ing. Through the spreading outside branches shine the re- volving sparkling deco- rations within. A storekeeper has fixed up a real live tree in his store window so that it willrevolve. He trimmed off the lower , branches of the tree, bored a hole through the floor of the window and in- serted the end of the tree. On _this he placed a split pulley and then fastened the end down to a re- volving pedestal. He connected the pulley to a motor and started the motor. The motor made the pulley go round, and the pulley made the tree go round. And on the tree were many electric lights. And the results were great beauty and many sales for the enterprising storekeeper. Showing how the motor turns the pulley and the pulley turns the tree OR our troops in Siberia there is an enemy stronger and more relentless than the Bolsheviki; and that is winter. Napoleon’s cohorts had a tilt with that same enemy in the less severe climate of Russia proper, and came off second best, finding on the great retreat from Moscow that the numbing cold clutching at their vitals and the drifting snow drag- ging at their legs were more deadly than the Cossacks. In Siberia the Yankee fight- ing men will face a cold more extreme than Napoleon’s troops knew. Even in the southern parts the winter bites deep. The extensive lowlands as well as the elevated plains lie open to the Arctic Ocean. The air, after being chilled on the plateaus, drifts down upon the lowlands, and in the re- gion of the lower Lena ex- tremely low temperatures ob- tain. Verkhoyansk isknownas “the pole of cold of the eastern © Committee on Public Information He is fully equipped with fur-lined parka, fur mittens and cap atmosphere.” The average temperature in December and January at Yakutsk is —40.2° F. and at Verkhoyansk —53.1° F., and occasionally the cold is so severe that official ther- mometers register as low as —75° and —85° F. To work and fight in tem- peratures such as these, an army needs the equipment of an Arctic expedition. For- tunately, our own northern border is cold enough to have been a good laboratory in which to work out ideas for clothing soldiers in winter, and the Yankee in Siberia will be armed against the elements. The War Department has devised fur-lined coats, fur helmets, fur gauntlets, and Arctic-proved footwear for our men. The equipment was assembled in San Francisco, and by the time you read this it has long been in service. A New York commuter looking at the pictures will sigh for Siberia and its comforts. 38 © Committee on Public Information With helmet closed and collar turned up, feady for a tilt with ice and snow ee la ore ee ee ae eee ee oe ee a a ae eo a ~~ + te th he fs be 4 A 6m. “sé * ee eee —_ oa - he

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.) oe”) Se Te le tte a ae Tiiad he January, 191° Cee > ¢ r = a 7, i, ee v ” Bs satiate of all the elements, is the es- sential factor without which the war for democracy could not have been won. In the last analysis, war is an effort to discover which of two sides can liberate the most nitrogen where it will do the greatest damage. For all explosives are nitrogen com- pounds—their deadly effects the result of the ineradicable tendency of this liberty-loving gas to burst its honds and hurl in every direction fragments of whatever has served to restrain it. From old-fashioned black powder to the most modern.and powerful trini- Nora the the most democratic trotoluol, or “‘T.N.T.,”’ nitrogen is the. basis of them ‘all. Even more essential, in peace, is the possession of nitrogen in usable form. Without its aid there could be no plant growth, nor could animal life upon this globe continue. Yet, while nitrogen is literally as common as air, since four fifths “of the volume of the earth’s atmosphere is free nitrogen (serving to dilute the essential oxygen and make it breathable, so that you would not be literally burned alive), the problem ‘of obtaining sufficient nitro- gen is one that holds the serious, even apprehensive attention of scientists, economists, and the Government itself. Before the world became densely populated with people who live in cities, and who therefore depend upon the annual crops produced by others for their food, instead of living on the This Chilean desert was once the world’s only source of fixed nitrogen Nitrogen in War and in Peace It helped to make the world safe for democracy and it keeps us from starving By Frank Parker Stockbridge fruits, nuts, and game that were the food of our ancestors, nobody worried about nitrogen. People went where food could be obtained; if they failed to arrive soon enough they starved. When the World Faced Starvation Up to less than a hundred years ago, the entire human race was constantly menaced by the possibility of famine and wholesale starvation, and nature’s methods of supplying nitrogen to plants through the action of bacteria in the soil long ago became too slow to keep pace with the increasing de- mand of the human race for food. For a great many years the world has been dependent for its supply of nitro- Wk 77 bb Circular arc flames This shows the triangular arrangement of three Birkeland-Eyde single-phase furnaces with six adjustable electrodes 39 gen for fertilizer upon enormous depos- its of sodium nitrate, or Chile saltpeter, found in the high, arid desert regions of Chile and Peru and nowhere else. In late years there has been an ime portant addition to this diminishing re- source—the production of ammonium sulphate as a by-product of the coking of coal. But the total annual supply from both of these sources, about 2,500,000 tons from-each, is still in- sufficient to meet the growing demand for agricultural purposes alone, while the war’s demands created a situation little short of critical. Crookes’ Advice to Chemists Twenty years ago Sir William Crookes, then president of the British Association, startled us by declaring that the population of the world was increasing so much~ faster than. its food supply that the race would-soon face starvation unless new means of increasing the earth’s fertility were found. His words carried conviction, and his suggestion that chemists turn their attention to the development of practical artificial means of extracting the nitrogen of the air and ‘“‘fixing”’ it in usable compounds stimulated experiment in that direction. As a laboratory experiment, the fixation of atmospheric nitrogen was old. The main essential of all processes then known, tremendously high tem- peratures, running up even to 6,000°F.,

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SON Nt ee made the practical application of any of them doubtful. - Chemists, how- ever, set to work. The development of hydro-electric power at Niagara and elsewhere, which made it possible to produce high temperatures through the electrie arc, turned attention to this means of accomplishing.’ the result sought. Charles S. Bradley, an American engineer, almost at the time Sir William Crookes was pointing out the imminent need, began the first large-scaleexperiment at Niagara Falls. His process was not a commercial success, but a little later a plant was established at Notodden, Norway, where water-power costs only $3 a year per horsepower. There nitrogen products were successfully made. Reducing Nitrogen: from the Air The process used at Notodden and later at several other plants in Norway, known as the Birkeland-Eyde; is not unlike that devised by Bradley. An electric arc is produced by leading a current of about 5,000 volts equatori- ally between the poles of an electro- magnet. This produces what is prac- tically a disk of flame six and a half feet in diameter and having a tempera- ture of about 3,000° F. The disk really consists of a series of successive ares which increase in size until they burst. Air is passed through this arc. The first product of the reaction is nitric oxide, which, on cooling with the residual gases, produces nitrogen peroxide. The cooled gases are then led into towers, where they meet a stream of water coming in the opposite direction. Thus nitric acid is formed high temperature. in the towers, in diminishing degrees of dilution. In the last tower the re- maining gases are brought into contact with milk of lime, which combines with the gases to form calcium nitrate and nitrite. The nitric acid obtained in the other towers is combined with a base. to form a commercial compound. These Norwegian plants were fi- nanced by Germany, and their output of fixed nitrogen was almost entirely absorbed by that country. At the Heating a. Furnace r Reaction / chamber In the Haber proc- ess an arrangement like this is used to produce ammonia synthetically from atmospheric nitrogen beginning of the war the annual production of the Norwegian plants was equal to about 10,000 tons of fixed nitrogen a year. At that time Germany imported annually 880,000 tons of nitrate of soda, equal to 137,000 tons of nitrogen. At the beginning of the war Germany had a stock of 1,000,000 tons of nitrate, equivalent to 156,000 tons of nitrogen, and a by- product ammonia capacity of 550,000 tons of sulphate of ammonia, equiv- alent to 113,000 tons of nitrogen. It is known that the Norwegian plants have not been commercially successful. In Germany several other processes for the fixation of atmos- In the electric furnace shown here calcium carbide is made by fusing lime and coke at a The carbide combines with nitrogen at 2000° F. to form cyanamid 40 pheric nitrogen were developed, all of which helped to supply the enor. mous quantity of nitrogen products: required in manufacturing explosives, One of these processes, developed by two German scientists, Drs. Frank and Caro, who began their, experi- ments in 1898, is known as the cyana- mid process. It is based upon the fact that calcium carbide, largely pro- duced as a source of acetylene gas, may be induced with comparative ease to absorb nitrogen, thus forming a com: bination of calcium, carbon, and nitro- gen, known commercially as cyanamid, This is the only process that has been installed on the American continent, a plant in Canada, at Niagara Falls, © having been in operation for several years, with an annual capacity of about 60,000 tons. Production of Cyanamid Thecarbideis placed inthe furnace and the reaction is initiated by local resist- ance heating to a temperature of 1500°- 2000°.F., the conversion proceeding — to completion without further heating. The nitrogen is obtained from liquid air, manufactured by compressing air to a density of 500 pounds to the square inch and cooling by expansion. When the liquid air begins to rise above its normal temperature of —313° F., pure nitrogen boils off. The compound of calcium carbide and nitrogen, known commercially as cyanamid, is itself valuable as a fertilizer; by treatment with superheated steam its nitrogen may be released to enter into combina. tion with the steam, forming am- monia. Popular Science Monthly 2 In Germany about 600,000 | a of fe ern oe ae ee a ee ae, ee |

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| Pie a es re A Se eae PS" Be” TF a tw a

tons of cyanamid is being produced January, 1919 annually. ; The other process of fixing atmos- .pheric nitrogen, on which Germany mainly relies, is the Haber process. In this, nitrogen and hydrogen gases, under a pressure of 1,500 pounds to the square inch, are passed through a chamber electrically heated to a tem- perature of 1,170° F. As a result, the nitrogen combines with the hydrogen to form ammonia. Although this process has long been in operation in Germany, its teehnical details have been carefully guarded, and it took chemical and electrical experts em- ployed by the United States Govern- ment nearly a year to discover its secret from patents obtained in this country. The Haber Process The Haber process involves the presence of what is known in chemistry . asa “catalyst.” It has ean « @e .26 @ SCaeems 6H 8S ee @ «Bev Making pure nitrogen gas by distilling liquid air formed under a pressure of 500 pounds to the square inch at a temperature of 313° below zero, one of the features of the cyanamid process sists of a small bit of -“‘spongy plat- inum,”’ or asbestos, fibers coated with platinum black. When this is held over an open unlighted gas-burner, the presence of the’ platinum causes the hydrogen in the gas to combine with the oxygen in the air with such speed and violence that great heat is generated by the reaction, the spongy platinum becomes incandes- cent, and in a second or two is so hot that the gas ignites. In the Haber process the catalyst is spongy iron, although any one of several other substances probably would answer as well. In the electric are process the first product is nitric acid, which is directly usable for explosives. In the cyana- mid and Haber processes the ammonia product is best adapted for use as fertilizer, but is readily convertible into nitric acid by passing a mixture ‘of ammonia and air through a red-hot platinum screen acting as a catalyst.

—_—-. <a oe a & Gee Gor Zp L. st sorrento:

The fact that nitrogen can be fixed directly in the form of sodium cyanide by the action of nitrogen gas on a mixture of soda and coke has been known for many years; but, while English, German, and American scien- tists have tried their hands on a com- mercial adaptation of this reaction, it is only recently that an American firm has been able to prepare sodium cyanide for the market by this process. A Low-Temperature Process Intensive study of the various meth- ods of speeding up the reaction has led to the adoption of special apparatus, and, at a temperature around 1800° F., with the assistance of a specially de- veloped catalyzer, an unusually pure cyanide is formed. From the cyanide it is easy to prepare ammonia quanti- tatively. One advantage of this sodium cya- nide method of fixation, aside from the low temperatures used,

been found that certain elements or compounds —the list is constantly being enlarged—have the remarkable prop- erty cf causing other substances to com- bine chemically, often in entirely new for- mations, without themselves under- going any change or entering into the new combination. A fa- miliar example is the common device for gas without matches, which con-

The crude nitrate is shoveled into i leaching-vats, where it is purified ee £ ee a

41 The nitrate mining in Chile is nearly all surface work at little cost is that when ammonia is made from the cya- nide, another product of commercial value is also obtained—sodium formate. This‘ latter material can be used as a starting-point for a number of artificial fla- voring oils, for a whole line of useful solvents, or for making the for- mic and oxalic acids . that are so necessary in our dyeing processes, for instance, and which were formerly imported, chiefly from Germany,

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Ts MOC SA Na: ee ey ae " + Se PEt mG ae Ra Extracting An X-ray photograph showing a diseased “rheumatic” joint HEN you have an ache in an elbow ora knee, you speak of your “rheumatism,” and often attribute it to a change in the weather. But that same “rheumatism” is usually caused by germs, microbes, or bacteria located in some other part of your body. Often there is a pocket of pus, or germs, hidden away in the root of a tooth you think issound. One day you begin to have severe twinges of ‘‘rheu- matism” in your big toe. That is be- cause members of that little colony of germs located at the root of your tooth have started on the war-path. They are sending out a few scouts and much poison gas into your blood and lymph. These enterprising little germs snoop around, keeping away from your leucocytes, or white blood corpuscles, and anti-poison tissues, always watch- fully waiting for their big chance, The soldier on the table is suffering with an ailment of a rib, which the surgeon is treating with Dr. Pridham’s double nitro salts applied externally , which comes when you inflict a slight injury on yourself. You may not notice that you stumbled and hurt that big toe joint, but the scouts from that germ colony noticed it, because they have found a weakened spot that cannot resist their onslaughts. They arrive in droves and feed on that spot, lodging there until they have set up an inflammation which you call “rheumatism.” Tubercle bacilli sloughed off the edge of a consumptive’s lungs or. intestines will do the same thing as the germs from the pus pocket on your tooth. Diseased tonsils, dysentery bacilli in the bowels, scarle- tina germs in the throat, pneumonia cocci in the lungs, adenoids, stone in the bladder, urological diseases, or any Popular Science Monthly Rheumatism through the Skin Inflammation drawn out on the skin by the Pridham treatment spot where a nest of germs is located, may be the start- ing-point of “rheumatism.” Dr. Fred Pridham, of Johns Hopkins Hospital in Baltimore, has devised a treatment. for joint affections that is being used very successfully at the military hospitals where it has been introduced. He uses a mineral, double nitro-peroxide, which actually extracts the inflammation. The salt is mixed with a starchy substance which holds its action until it is placed on the skin over the dis- eased bone, from which it extracts the impurities, the germs, and their poisons. The material is sprinkled: on lint or gauze and placed on the skin over the diseased bone. When the doctor removes the dressings from six to twelve hours later, there will be seen blisters on the skin. If there is no infection the salt will not affect the skin. Voice-Tubes for the Ship’s Gunners. N a naval battle, the range is ob- In big battles the gun that has but tained principally by men stationed one channel of communication stands in the mast-tops, the readings of the grave chances of being cut off from the instruments being tele- rest of the ship. Should that happen, the gunners would have to depend upon the gun’s telescopic sights, and there would be no checking phoned down to the officers in the plotting-room below the warship’s deck. Here the instrument readings are quickly transcribed into terms of gun ranges and of angles of horizontal deflec- tion. e These calculations are then sent to the gunners through speaking-tubes, al- though telephones and nu- meral indicators are often used, to make sure that the orders will be understood. For, when the battle waxes hottest, either a voice-tube or a telephone is likely to be swept away. up of hits or misses by the spotters in the mast- tops. Thus the means of com- munication is the crux in the modern method of pointing and firing a_ battleship’s guns. In our Navy, voice- tubes are generally pre- ferred to electrical appara- tus. The speaking-tubes are metallic pipes made air- tight to conduct the sounds efficiently. Nothing short of a rupture or a large hole Here is a voice-tube equipped with a megaphone outlet which increases the intensity of the sound. This photo- graph was taken on board of the U. S. S. Jouelt 42 torn in the tube by shell- fire will impair its operation to a dangerous extent.

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irt- of in | a t is the een ible acts ‘chy intil dis- the cheir lint over ctor x to seen s no skin. ppen, pend , and cking s by mast- com- in the inting ship’s voice- pre- »para- s are > air- sounds short e hole shell- ration

January, 1919 Press the Button—See the Show How a little switchboard runs a theater employing more than a thousand persons OU are going to forget your cares and worries in an evening at New York’s Hippodrome. You go early so as not to miss anything. Just as you settle into your seat the orches- tra begins to play. In By A. M. Jungmann little electric switchboard operated by Clyde W. Powers, the stage director. Every time Mr. Powers pushes a but- ton he starts something. When ‘the orchestra begins to play, it is because Mr. Powers communicates the need of a new light by pressing a button. Fach act is carefully timed. So many minutes must be allowed for a certain actor to do his part, so many seconds for another. Mr. Powers

a few moments the show ison. The great red velvet . curtains are drawn back, and tableau after tableau is presented to your eyes. Hundreds of performers throng the stage. Ele- phants and horses do their acts. The great tank is opened, and diving girls splash in. Repairs Behind the es Between the first and second act, your wife turns to you with, “Oh! Look, Henry, that lovely velvet curtain has a big tear in it!” You look, but don’t see the rent. While your wife tries to show it to you, the

DARK

SIGNAL FOP. 44% STREET SIDE

—— counts the minutes and the seconds as a miser counts his gold—-nothing escapes him. In a sense, the - audience is timed too, for favorite actors are per- mitted a few seconds be- yond the time for their acts in order to receive the applause of the audi- ence. After a show has been on a few days, the time the big hits require for applause is definitely set, and no actor may bow more bows than can be made in that time. When the last second ‘arrives, one of the little buttons on the switchboard is pressed and the next cue is taken. Suppose this efficient

How the show at the New York

. é V UD KING INE <Q GETTING ANY PIECE ONTO Ti Slacclesn a dieciek. The RECEIVER. Lo , SPEA\ PHO. : \o WHITE THE RUNWAY" stage director doesn’t yell, ‘‘Here, = TREASURY @o—nis SIGNAL EMBRACES you elephant man, bring us your YN STAGE DOOR. ALL THE LIGHTS, ON OR. OFF elephants.”” He just presses a ( 1 im) ORCHESTRA. 3<-SWITCH THAT TURNS ON button. In one hundred and \ 7 SW. BRIDGE CURRENT TO LIGHT UP GIRLS’ seventy-four minutes two hun- = COAT ROOM ING SUITS IN WATER SCENE dred and twenty cues are given pee 7 43 GALLERY CENTR. GALLERY 44 GALLERY “geeennies witen. | SSE doves Details of the Should the switch- i. 44 VEILVETS ‘VELVETS" ‘nde gg lO wonder - working board fail (it never 18/8/¢/8/6/6/4/ 6/779 M8 BURNSIDE ee switchboard which has) the telephone os = FRONT GRIDIRON 43% ST FLY BRIDGE CONTROLS FRONT CURTAIN controls the en- is at the service of SWINGING 42 BACKCELL RINGS CELLAR. GONG 44™ ST FLY BRIDGE trances and exits the stage manager FLY/DAIDGE\'43 GRIDINON DOME SIOTING Au CONTROLS FLYING APPARATUS Of 1074 persons for the emergency RUN BRIDGE '44GRIDINON PICTURE 6H

curtains are drawn back and the next act begins.- “Never mind, Henry,’’ whispers friend wife, ‘‘I’ll show it to you next time.” Womanlike she doesn’t forget; but when the great red curtains are drawn across the stage again, your wife can’t find the tear. You think it wasn’t there. It was. While you were watching the stage, busy tailors neatly darned the rent. Suddenly you say to your wife: “Say, there must be an awful racket out back of the scenes. Directors \ yelling at all that crowd and getting everybody in on time.” “T don’t hear it,” she replies. Don’t look patronizingly at her. ere isn’t. any noise—no one yelling orders. The whole show is run by a a button has been pressed. Every- . thing you see done is done in re- sponse to a button on that little board. Actors, musicians, property- men, carpenters, -electricians, tailors, animals, all obey the buttons. No one says anything. One thousand and seventy-four persons help make your evening a success by obeying the orders of these little electric buttons. Even the Audience Is Timed The performance lasts just one hundred and seventy-four minutes. In that time Mr. Powers gives two hundred and twenty cues by pressing the buttons on his switchboard. [If an electric light bulb is not lighted, no one shouts for the electricians; 43 little switchboard were to get out of order, what then? There is a tele- phone, and, if that fails, a speaking- tube is ready to carry the orders that direct the show. But, so far, the little switchboard has never failed. Obedience the Watch-Word The .same system is used in re- hearsals. At no time is shouting or confusion permitted behind the scenes. So thoroughly is the idea of immediate obedience ingrained in all Hippodrome employees that a signal must be obeyed no matter when it is received. If the elephants were summoned on the stage at an hour when the elephant man knew there was no rehearsal, he would lose no time in marching his beasts up the runway and on the stage,

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> LL RE LL Wa GE OMA LO LOOM UMRLM ELUTE Lou ltt A catchy cover is almost as impor- tantasacatchytune. Examining designs for a hoped-to-be song hit At this stage the plate from which notes and words are to be printed is etched in an acid bath The “‘router’’ must carefully cut away the metal to make the notes and word type ready for printing Printing a sheet on metal by a photo- Popular Science Monthly x + VL LL udddldddddddddddddddddd ddd Ld ladles dade SREB NHN TZ PSST TORTI SAAR . One of the first steps is to photo- graph the artist’s cover picture to make it ready for engraving SAAN OMIM ELUM EYEE YOO Mii teed graphic process preparatory to etching the plates from which the song will be printed The notes are very hard to etch; so, after the acid bath, they are hammered in by an expert The song being fed to the binding machine, nearly ready to go out in its glory of fresh print to a waiting world CMM le LALO MALT CULMS MEN LAMM DULDY 44 cite ere une mametts. ate Wi ABA TROLL

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January, 1919 * is % All wrapped up in this blanket built with sec- tions of wool, canvas, and asbestos with wires stitched in, all he has to do is plug in on the electric lighting circuit and sweat out that cold. Charles Fogel- song, of St. Paul, has patented this idea = Cold? Press the Button Carry an electric stove in your glove, and fight chills with the modern substitute for mustard Charles Doehring, of New York, has fixed things so you can get a sand and elec- tric bath all in one. He tucks you in your cozy _ sand-bed with flexible metal sheets between which the electric current is generated No more need the motorman blow on chilled fingers. Alois Zeckendorf, of Cincin- nati, has invented an asbestos pad filled with wires to go in glove or mitten. The motor- man hitches up _ his glove to the car cur- rent and is comfortable With this electrically heat- ed bath-robe—for which Edwin B. Rayner, of Piqua, Ohio, stands spon- sor—you can shave in comfort in the coldest bath-room. But primari- ly the device is intended as a convenient way of giving electric treatment Not forgetting the horse, Ida Fogelsong, of St. Paul, has invented an electric blanket that will sweat out old Dobbin’s ills Swathed in this . electric ‘ sweating-robe invented by ‘Andrew Phillips, of St. Louis, he gets Turkish bath results without hav- ing to tip the rubber. The robe is a two-layer affair with the current- carrying wires worked in between the seams ; i 4 as 1 }

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Making Your Canary Feel at Home If you take the proper care of your canary, you ll never need to ask, “Dick bird, Dicky bird, why don’t you sing?” ¢ BOUT fourteen distinct strains A of canaries are known, and an almost endless number of varie- ties. The common canary is reared primarily for its song. Before the war song canaries were reared in Germany; now most of the singing birds come from England. There is no reason why. Americans should not train their own singing canaries. It seems to be necessary merely to put the birds in a room with good songsters, the vocal powers being developed through imitation. But careful watch must be kept, and a bird that develops harsh notes must be promptly removed; he must not cor- rupt the purity of the tone of his brothers. Sometimes a mechanical “thriller” is utilized in training, when the birds are silent, as during the moulting period. Jn six months or less the education of a singing bird is com- pleted. ‘Mr. Alexander Wetmore, Assistant Biologist of the Biological Survey, U. S. Department of Agriculture, has given the subject of the management and care of canaries so much attention that we cannot do better than to abstract one of his papers on the subject. Make the Bird Comfortable First of all, he assures us that cages should be chosen is best. For a single bird, the cage should be at least 9!% inches long, 6% inches wide, and 9 inches high. A fine-mesh screen may be secured from the dealer and fastened around the lower half of the cage to prevent the scat- tering of seeds and_ seed-hulls. A common substitute for this is a muslin bag, held in placeby a draw-string around the middle of the cage. In a cage of the ordinary */ size three perches are suffi- cient. One should be placed at either end, at a distance that will allow easy access to the food and water recepta- cles, and the third elevated above the middle of the cage. For reasons of cleanliness, one perch should not be directly above another. An English au- thority gives the stand- ard size for This bird, a crested canary, is like a _Skye terrier inas- much as its eyes are entirely con- cealed by itstopknot Popular Science Monthly The crest of feathers on its head sets this bird apart from the every-day canary tom covered with several thicknesses of paper. A better plan is to use the heavy coarse-grade sandpaper, known as gravel-paper, that may be secured from bird dealers. This should be renewed whenever the cage is cleaned, and in addition the pan should be washed in hot water from time to time. What to Feed the Birds The food requirements of canaries are very simple. The prime requisite is a supply of canary seed to which is added a small quantity of rape seed and a little hemp. If canaries do not seem to thrive, it is well to examine the seed supply and crack open a few of the seeds to make certain that empty husks alone are not being giusatily teceomfort: Th 5 fed. Too much hemp marily omiort. e A : avoi square cage, in his opinion, Scotch fancy canary Instead of being yellow, this bird, seed should be avoided ‘ > bird—bred to develop the lizerd canary, has varie- as it is very fattening. the hump on its back Another canary with a hump on its back, the Belgian fancy; it is a very rare bird breeding cages as 22 inches long, 12 inches wide, and 16 inches high. Sev- eral types of open breeding cages made of wire may be obtained, or a box with a wire front may be made. Care of the Cages Though canaries, when acclimated, can endure a great degree of cold, they are very susceptible to sudden changes in temperature, and cold drafts are fatal. This should be borne in mind in choosing a place for the cage. The room must be kept at a fairly even temperature, day and night. Wherever placed, the cage must be kept scrupulously clean. Seed sup- plies must be replenished and water renewed each day. The receptacles for these necessities should be cleaned and washed carefully at short inter- vals. Cages that have removable bases should have the tray in the bot- 46 gated plumage; hence its name In addition to this staple diet, lettuce, chickweed, or a bit of apple should be placed between the wires of the cage frequently. Bread that has _ been moistened in scalded milk, given cold, is also beneficial at times. Perhaps once a week egg.food may be given. This is prepared by mincing an entire hard-boiled egg and adding to it an equal quantity of bread or unsalted cracker crumbs. Cuttle-bone should always be available to the canary. In the breeding season egg food must be given daily as soon as the birds are paired. It may be discontinued or given at intervals of three or four days when the female is incubating. The yolk of hard-boiled egg only may be given for the first day after the young hatch. Seed should always be provided. Under normal conditions most birds probably bathe daily. China dishes that are not too deep make good bath- ing receptacles. In winter the water should be warmed until tepid.

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alll we January, 1919 The Community House for Soldiers An experiment in democracy conducted by several war organizations and financed by the people of Ohio N army representative of the A highest type of American de- mocracy cannot be turned out by military machinery alone. We have come to regard the contentment of men in training as vital. To the American Recreation Associa- tion, operating in their war work under the name of War Camp Community Service, fell a difficult task. Making sure that the men find available the best, and only the best, that the particular community affords, has been their task. Into more than six hundred towns and cities the W.C.C.S. has sent trained workers. In stimu- lating each community to utilize its own resources in the most effective manner, some unique institutions were evolved. A Unique Community House The first Community House was built at Manhattan, Kansas. The most interesting one, structurally at least, is at Chillicothe, Ohio, near Camp Sherman. It is in the form of a great Maltese cross. The people of the State of Ohio were asked to furnish the funds for its construction and equipment. By Raymond B. Fosdick The Camp Sherman Community House has become the Mecca of people from all over the country who come to be near their sons, husbands, sweet- hearts, and brothers in the camp. Here, too, the townspeopie mingle freely with the soldiers; and the com- munity activities, the musical life of the town, home talent entertainments, and social life generally is conducted on a scale heretofore impossible with small-town facilities. An Experiment in Democracy The lounge, occupying the entire central space of the building, opens on one side into the restaurant and on the other into the auditorium with its stage extending across one end; and when these three rooms are thrown into one, as can be easily accomplished, their seating capacity is fifteen hun- dred. A large reading and writing room occupies the fourth wing of the house, and from it open women’s rest rooms and small parlors. Built on the curved driveway lead- ing from this central building to the main thoroughfare, are the other hostelries of the “community’’—each a model lodge in itself, harmonizing STORE ROOM Meee a ee Be Hall UAL Ss 5 It was constructed jointly by several war organizations, and administered by War Camp Community 2 Rr EEN in color and architecture with the main structure. These provide sleep- ing-rooms with baths, writing-rooms, smoking-rooms, and women’s parlors. The Community House was an ex- periment in democracy. The results are gratifying. There is noticeable be- tween the officers and men a cordiality that old-time military. authorities would have declared impossible. The change in the attitude of com- manding officers in regard also to bringing women into the camp en- vironment is interesting to observe. A Contribution to Community Life It was General Glenn who did most to hasten the building of the Camp Sherman House, and to make sure that every comfort was furnished the fami- lies of the men coming there. The Community House means the re- establishment of the normal social relations of life for the service men, and I am sure that every dollar which Manhattan, Kansas, or Junction City, or any other town has raised by bond issue, or the State of Ohio or the Rotary Club have pledged, will con- tribute not only to the soldiers’ need, but to attaining the ideal town life. Le, Se wees % AAG OAAOAWWMBWNWY Service, its object being to promote cordial social relationships between civilians and soldiers 47

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RHEOSTAT

This shield of prismatic glass deflects the glare of your lamp AMARA a The trolley-repair automobile, equip. ped with ladders, tools, and material, has proved effective in Cincinnati

PiN ON CYLINDER HEAD / INTERNAL GEARTCAM To remove the cylinder-head turn the eccentric lever fastener of the claw-clamps and slip off pins To increase the traction power of small cars pulling a heavy ¢ load, they may be coupled by loading the forward end of each car upon the truck ahead

VOLT METER. Popular Science Monthly \ ® Some New Answers “™ : ' : . __. What invention and ingenuity (ee and comfort of truck, <— TAN K The rheostat indicates on your FLOAT, voltmeter the number of gallons ‘of gasoline in your tank RANA NNN EEE LES ou my had Double-width traction wheels: enable this heavy tractor to travel over soft ground without sinking in the earth

SEAT yaaa NT The lock-bar shown here is the latest in- vention for foiling the automobile thieves. It is simple, easily at- tached, and per- mits the moving of the car in case of fire SAO AANA ANH SHKW JAW MEMBERS oe Put the spring jaws of the plow-beam in the coupler, insert the wedge-block, and your plow is coupled i 48

rere on OP

RR AGES LLGTE EUS A EN re

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We 1 SEA AAD EN Ng SSNS WANN oH ATT SMW AV AVG NY HET “January, 1919 to Automotive Problems "Qs" are doing to add to. the efficiency seni tractor, and pleasure cars A new electric heater for the intake manifold that will aid in starting the automobile engine PRESSURE INDICATOR. This device indicates automatically the air pressure in your tire gg RENAN NANETTE SS or ee automobile truck and trailer are used to carry the men from the end of the car-line to the mill and back again SUMULLMULOOMMUM hLDA CLM a UE ge le GUL MULL ULL OOO OULD AD OCCT HLM iil is shih thet case ANSON —— geeenegg SONS NN TRAS ENN NNN TTITT % N a s = € ‘s X N 3 This shock-absorber for Fords has three coiled springs and four of them are used for each car A rolling-mill in Ohio is located about five miles from the nearest city. To solve the transportation problem, an ’ If you tise one of these pneumatic jacks it will be possible for your engine to lift ‘the car by air-pressure You can try the petcocks of your oil channels without any discomfort by rods extending to the running-board Ce ie ri To ‘take up the wear of the worm- \ 7 gear of the Steering ‘OPERATING NFO = device, a mechanic WIRE has invented this. adjustable:- @ccen- ‘tric shaft bearing EXHAUST MANIFOLD Se f ES ECCENTRIC This new type of automobile BUSHING exhaust-gas whistle requires no electric current. to operate it. ae It is mounted on the exhaust This collapsible cot with a mattress. and manifold, and is set in action by tent roof, is likely to appeal to a wire from the panel-board - automobile tourists for economic reasons 49 , ~ 8

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Popular Science Monthly How the Cipher Expert Works The message that reaches him may be a wild jumble of letters and figures, but it soon gives up its meaning HE military cipher expert gains | only a small share of war’s honors or glory; but in the quiet of his office, his swift, subtle, and scien- tific efforts in deciphering intercepted dispatches and orders many times bring defeat and disaster to the enemy. Other branches of the military serv- ice, engaged upon more active duty, gather the material, which is laid later . before the man whose task is the solu-- tion of ciphers abstracted from enemy communications. The scout patrol- boat, silently plowing the waters off our. Atlantic coast in its quest for sub- marines, suddenly picks up from the ether the following message, which is recorded by the reeeiving instrument of the wireless operator on board: 3SIUOWSESILDRZLALA NABDEnLYDaNLFCOETI UORGHFKAIRLMTEMT The wireless operator instantly perceives that this is only too evi- dently a cipher dispatch of the. enemy; and, since there are no other enemy craft suspected of being in these waters, it must be a communication sent by one U-boat to another. No Cipher Indecipherable The message is at once rushed by the quickest available means to the nearest office of the Intelligence Department, where it is submitted to the scrutiny of the cipher expert. It is accepted by him as an axiom that no practicable mili- tary cipher is mathematically indecipherable. But it requires a remarkably long time, as a rule, to decipher even the sim- plest kind of message. There- fore speed is éssential, so that advantage can be taken of the news contained in this secret communication before it is too late. ‘$o the cipher expert starts to work, immediately. His office is amply supplied with all the known data and material by means of which the most up-to-date cipher communica- tion may be solved. He is provided with tables of fre- quency of the language of the enemy country, covering single letters and digraphs of duals or pairs. He knows that ciphers are divided into two general By Charles A. Collman classes—the transposition cipher and the substitution cipher; and his first endeavor is to learn in’ which class this dispatch belongs. How the. Human Mind Works Substitution ciphers may be made up of substituted letters, numerals, conventional signs, or combinations of all three. The human mind works along the same: lines always. The in- ventive man creates, but his supposed invention is, in principle, many hun- dreds of years old. For instance, the basic system invented ,by the Abbot Tritheim (1462-1516) represents the foundation of the modern substitution 2 Ke E(5) S Bl WL) S/O] O(N) O a] [es] 9] — = oO €l al it a(n} olen fo}Em|[o;o 14 Neo st {ols ]0 oi=|2 (L)D ror D(4) (2) “Ti The pattern cipher cannot be decoded without the aid of this ground card "The sitinanines potter, which, whilin aicoaile on the ground card, discloses only the letters to be read 50 ciphers which are most widely used. Transposition ciphers are limited to the characters of the original text, which are rearranged singly according to some predetermined method or key. This method of secret writing is used to obviate the difficulty of deciphering substitution ciphers, since it is essential that the recipient of the message solve it quickly. Fortified with his knowledge of the various known cipher systeris, the cipher expert closely examines the message that has been submitted to his scrutiny. Much depends upon this initial scrutiny, in which all of his natural powers and talents are called into play. He soon makes up his mind that his frequency tables are of no use in this emergency, since this is not a substitution but a transposition cipher. Furthermore, he recognizes it as a special type of the latter class, from certain plain indications, such as the use of the figure ‘“3’’ and the junction of the letters ‘‘Da,’’ which represent a key. In fact, he suspects that he has before him a form of transposi- tion cipher known as the “net,” “pattern,” “stencil,” or ‘“‘lattice”’ cipher. As part of his office equipment, the expert is provided with most of the known forms of “nets” or “patterns,” which consist of per- forated squares of tin or cardboard. In this instance he discerns the use of the medium known as Fleissner’s improved pattern cipher, in which the pattern or stencil called into play has fifty-seven small round hole cuts out of or punched into the carton, each of which has room for one letter or number. The Fleissner ‘‘Pattern”’ The patternisa perfect square, and the perforations have been made according to certain mathematical calculations, so upon a sheet of paper, it may be moved in four different posi- tions, and, letters having been written each time in the open- ings, the entire pattern surface will be covered with a cipher of fifteen lines having fifteen letters each, or 225 letters in all. The reader need only refer to the accompanying chart to fashion for himself a pattern that, when the pattern is placed: ee eee 1p a eB

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Te = No. of Openings Letters Sixth square 13x13 169 Fifth square 11x11 121 _ Fourth square 9x9 81 Third square Tx7 _ 49 Second square 5x5 25 First square 8x 8. 9 January, 1919 out of a sheet of common writing paper, when the problem will present. itself to him in. the most simplified form. The entire pattern surface is divided into squares, running from:No. 1 to No. 7, and the size of the communica- tion will depend upon the squares selected, as follows: The entire pattern surface, that is, to the seventh square, presents 15x15 openings, or 225 letters How to Use the Pattern In the corners of the pattern are indicated the four different positions in- which it should be moved: namely, A, the first posi- tion; B, the second; C, the third; and D, the fourth. It is possible, also, by reversing the surface of the pattern, to obtain four ad- ditional positions (E,F,G,H); but, - since no communication of such ex- tended length is under consideration, this matter may be left to the further experimentation of the reader. The pattern should be moved always from left to right. From the above sum of the letter “openings should be deducted the central perforation, which is not intended for the substance of the cipher message. This opening has a special significance, since here is placed the capital letter (A, B, C, or D) that indicates the position of the pat- tern in which the enciphering of the message was begun. The cipher expert, bearing these facts in mind, recognizes from the use of the number **3” that the third square of the pattern has been adopted in writing “the cipher, and verifies this fact in that. exactly forty- nine letter openings have been used, although in two instances two _ letters each have been placed in the openings. Shifting the card about according to well known rules, he solves the ‘‘pattern’”’ cipher Now, in beginning his work of, de- ciphering, the expert draws on a sheet of paper a square that corresponds in size with the third square of the pattern, and fills it in with 7 x 7 small circles in positions corresponding with the pattern perforations. The next step that the expert takes is to write the letters and com- binations of letters of the hostile radio message, which results in a table of seven lines, of seven letters each, as follows: S I UO WS E S foe a A .L 2/R. Ae D En L Y Da N L F Gob SE BO R GH F K Atl Bh a a Mee -Now the decipherer places his pat- tern upon this table of letters, and discovers that the letters ‘Da” fit into the central hole. So it is evident to him that the writer of the message began his communica- tion with “‘D,”’ the fourth position. He therefore arranges the pattern so that “‘D(4)” appears in the upper left-hand corner, and the openings in the pattern disclose to him the following series of letters: SO R Z ALCTOKLM. This does not make sense, and the expert realizes that the writer adopted position ‘‘D” for purposes of mystification. Fur- ther observation inclines him to the belief that the use of “Da” as a key indicates that position “D” was utilized merely as a “stall,” and that the real message was begun with position “‘A.” The Message at Last Turning the pattern into the next position, with “‘A (1)” in the upper left-hand corner, he reads as follows: “Will BEN NE Fire—” He per- ceives that he has--hit upon the proper solution of the cipher, and, turning the pattern to the left again, to position “B,” then to position “‘C,” he obtains the remainder of: the message, which reads: ‘Will be N.N.E. Fire Island Light, Tuesday, four A.M.” All is now known. The proper naval authorities are notified, the — machinery of the coast defense is set in motion, and on the day, the hour, and in the position indicated, two U-boats are captured or sunk. And perhaps the cipher expert gains at least part of the credit of the achievement. It may be found interesting to con- struct a-pattern such as the one pre- sented out-of tin, cardboard, or even writing paper. The perforations can readily be cut out with a penknife. MODERN : army without Hello, Central! cu Me Berlin In addition to seeing that telephone service is in about the same fix as a big city would be if all the wires should go dead. It follows that every effort must be made to keep the telephone service in the field at top-notchefficiency, and therefore daring linemen and operators follow close at the:-heels of the troops. “On the fighting line ‘“‘cen- tral’’ is housed far under-..- |} ground or in carefully camou- flaged shelters; but the larger stations back of the front are usually safe from all but aerial attack, and they set. up their switchboards in: thé com- parative:comfort of a large tent or, better still, an aban- doned house. messages go to the right on aT At least, an army “central” isn’t asked foolish questions, nor does he have to “listen in” to his gossipy neighbors 61 places, the telephone squad must watch out for breaks and make quick repairs. Formerly the squad had to be on the alert for an enemy . “listening in’; but in the latter part of the war the lines were so laid that the use of spy microphones by which messages were stolen from the wire was almost impossible. The army central’s task, while made less hazardous by peace, is none the less strenu- ous. The title of this article may literally be lived up ‘to, for the army centrals will have of food distribution among the starving enemy. a large part in aiding the work . -

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Now They Motor to the Round-Up Popular Science Monthly — time was, and not so very long ago, when the man who lived on the plains would jump on one of his cow-ponies and cut across the pasture-lands to the round-up.- Farmers nowadays go to different round-ups, and travel in an entirely different manner. The pony is left to nibble alfalfa while his master takes his Great Guns! place at the steering wheel of a modern motor-car and skims along good roads to the place of*the round-up, where at experiment stations he devotes his energies to learn- ing the best methods for getting hogs and sheep and cattle in prime condition. AN entertaining game for children bears the appropriate title “‘Great Oriental Monsters HEN you are in’ Japan, be. careful: not to ‘order two crabs for lunch, because... two Japanese crabs would keep you eating continuously for at least two days. Rather, ask for a crab’s foot, and you will have plenty. Japanese crabs,- unlike the people, grow to a large and ugly size. If you were to stretch out the two longest feet of one of them and stand him up on one pair of nippers, he would be at. least four feet tall. If the power of each pair of nippers cor- responds with the length of the leg to which it is at- tached, a Japanese crab on the end of your toe would most likely mean its loss. The smiling little Japanese lady has evidently not yet . been bitten. Guns!” It consists of a map of Europe in a frame, with a slit in each country to receive a “gun.”’ The object is to coax the guns into their appropriate slots. Removing the German Germs ANADIANS found this queer instrument outside a one- time German dug-out. When they turned the handle, blasts of impure German air gushed forth, while pure air poured in. It was a German machine for drawing bad air out of dug-outs, worked on the vacuum principle. Wayside Jewels US-RIDING in San Fran- cisco’ must be:-a- wild, precarious undertaking, forthe bus company there has just erected a box-safe in which to place the money and jewels of venturesome -joy-riders. The automobile starter, a very earnest man, is here shown locking up the safe after a bus-load has handed him their valuables. He alone knows the combination of the safe and is responsible for all contained therein, so he ‘needs must be a worthy person. Not only worthy, but brave; for some dark night, while waiting for the return of the riders, he may find himself surrounded by passing burglars. As to whether their jewels are safer here than on the bus must be decided by the owners. eS — Aim > *- et -e FD LJ fete tad Otte PROC lhe

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January, 1919 Here’s Another Riad Beenkiss 1% a moment of great patriotic fervor, five hundred tailors, re- siding mostly in Chicago, decided to build this flag. That it is enor- mous can readily be seen. But not only is it large—it is the largest ever made.- These fervent five hundred carried on a thorough in- vestigation of flags and their sizes before they started work on this one. They learned that the cham- pion was seventy-five by one hundred and fifty feet, and promptly decided to make theirs eighty by one hundred and sixty feet. And so this enormous creation is nearly thirteen thousand feet square. Each strip is.six feet wide-and each, star is five feet tall. At is so well put together Le Mosquitos Drove Them to It "THESE men ‘are not playing bugaboo with this soldier, nor are they modest Turks veiling their blushing faces, nor yet again are they ghosts that walk by night. They are sane, normal Italian soldiers very sensi- bly covered with mosquito netting prior to turning in for a night's rest. The com- fort of screened windows was not theirs in their rude homes on the Piave, and Austrian mosquitos had been in the habit of feasting greedily on their tired bodies as they tried tosleep. On this particular night, the pests . probably slunk away baffled. that there is no “‘wrong”’ and no “‘right’”’ side—both sides are the same. And the colors, too, are “fast,’’ so that no thunder shower will make it “run,’’ and no sunshine cause it to fade. In spite of its great size, the whole thing weighs only four hundred and fifty pounds, A Cafeteria for Pigs ORGING continually from morn till night - brings’ unto a pig peace, which in turn causeth fat. Since a pig’s function on earth is to grow fat, food should be ever- present in his sight. That this might be, some Ohio farmers built a self- feeder by means of which pigs can eat as much as they liked. . The self-feeder is a smaH house in which pig feed is stored. Outside of the house there are small com- partments in which different kinds of food are always present. This is made possible by adjustable slides which connect the compartments with the food-bins within. A steady flow of food slides down from the bins into the compartments. Piggy eats a little corn, and then some barley, and then something else. In spite of his greed, he knows what is good for him and never overeats. and is very easy tounfurl. When it was finished, the tailors dedi- cated it to their fellow workers who dropped their shears to take up guns. It made its debut from the City Hall building in Chicago on Labor Day. The affair was most impressive. A band of eight hundred sailors played the national anthem as the flag was unfurled. Then two hun- dred thousand people marched by and saluted it. It has since figured as. the star per- former in many patriotic — celebrations. Once it was the grand finale to a sham No Man’s Land battle which took place at a war exposition at Chicago. i" o at faa 5 Not at Home to the Enemy [N the earlier days of trench raiding on the western front, a young officer who had been studying medieval methods of defence decided to apply the idea to his trench section. The re- sult, shown in the picture, was generally adopted along the British front. The V - shaped _ gate swung outward on hinges at the top. When the Boches were behaving the gate was held up by a chain, per- | ee the adjoining trench. But in a raid the guard stood ready to drop the barbed- wire protection and secure it with an iron stake. mitting free passage into . a 2 STP ETE ETT EN | i

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i f Le | # i. An Electro-Magnetic Catapult to. Give Airplanes a Good Start ‘an airplane is shot from a catapult instead of starting _ entirely by its own power, not only can it be started flying more rapidly and in a smaller space, but it can be made to "carry « nearly. ten times more load. nd if the catapult ‘is built on the electro-magnetic plan it can be made to serve for airplanes of different design and size, including hydro-air- planes. ks a are the ideas that prompted Godfrey Lowell Czbot, of Boston, to design and patent a launching mechanism of the kind . mentioned. . The catapult takes the form of ~ an electrically driven carriage re- ceiving current from the rails on™ which the wheels travel, and com- pleting the circuit by means of a third rail between them. A brush attached to one wheel axle takes current to a motor geared to the front wheels, and also, by another wire, to the electro-magnet. The - second binding-posts are secured to shoes contacting with the third rail. Pt ti TY The third rail does not bevin at the starting end of the track, How to Keep a War Map Popular Science: Monthly That Betraying Column of Smoke— Force It Down to the Water T= bridge of an ordinary cargo vessel-rises to a height of from 33 to 35 feet above sea-level, and towers above the horizon visible to the observer on the bridge of a sub- marine at a distance of ten miles.” As a matter of fact, however, cargo ships of the average ‘type - usually be- tray their presence at ‘a very much greater distance because of the smoke that belches from their smokestacks. As early as thirty years ago, Sir Alfred Yarrow, the famous English naval architect, originat- ed a method for driving the smoke ’* from steamships downward. The necessity of giving greater protec- “tion «to cargo ships passing through the danger zone during _, the war caused a revival of inter- est in that plan, and extensive ex- effectiveness of the method. From the base of the smoke- stack, at an elevation of about six feet above the -deck, horizontal ducts are carried to the gunwales on each side of the ship. The periments were made proving the’ but a little farther on, the ~ idea being that the carriage and aircraft shall first be set ‘going by the propeller screw; - to make sure of the engine being in order. The car- riage and aircraft are hurled ‘forward together, and a speed is soon provided at which the aireraft is sure to fly. An indicator shows the aviator when that moment has arrived, and he signals IRST, get a good map, preferably in black and white, outer half of these ducts with light blue for the rivers. A-recent map prepared by the National Geographic Society can be purchased for one dollar. Then, procure some flat-headed colored pins. Next, take some highly colored floss or worsted—green, for example—and establish your battle-line by the morning newspaper. Make the whole line uniform green, with no attempt to differentiate between the different forces. When there is occasion to change the map, select bright yellow to establish the new line of advance, placing the pins in the names of the places captured and letting the yellow floss be guided from the points on the green line where the change has taken place. slope down at an angle of about 45 degrees. Normally these ducts are closed by dampers on the inside, close to the smokestack. On the in- side of each duct, just above the knee, nozzles eject a cone of water spray under a pressure of 150 pounds to the square inch. When it is desired to divert the smoke, the damper of to the operator of the launching machine, who at once cuts off the the duct on the lee side of the ship is opened, the damper of the smokestack current by means of the rheostat- sititaei ahaa is closed, and the water supplying the controller. The magnet lets go, and nozzle in the respective duct turned on. the aircraft sails into the atmos- : The cold water cools the gases, and phere. ——— this and the force of the spray cause The carriage is brought to a stop ) «Teach the smoke and gases to descend to the by automatic brakes. ELECTRO MAGNET water and settle. Oj INSULATING HOUSING > = FOR MAGNET re Pe: “SHOES ON THIRD RAIL The inventor of this starting apparatus claims that, besides flying more quickly, the airplane will carry a greater load Smoke from an ordinary cargo vessel can be seen for a distance of seventeen miles. Here it is forced down by water spray

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January, 1919 fan £ The man who named this, type of boat a “snag” boat was surely tempting fate. Fate accepied the challenge, and here is the result. Ho- ratio C. Wright has completely lost his starboard side— lost it to a barge HE Arctic region is not the only place where people can see huge masses of snow and ice heaped up. On our own Mississippi River in the winter-time there is a spectacular dis- play of icy things, with the additional attraction of several wrecked ships and ‘ barges. For the severe ice conditions due to the bitter cold play havoc with the river boats, throwing them about in most undignified fashion. The region around Cairo, which lies at. the junction of the Mississippi-and Ohio rivers, suffers most. But Vicks- burg, Memphis, and St. Louis are by no means overlooked. Early in De- cember the mercury usually slips down Ice Gorges in the Mis “masses. A Winter’s Tale below the zero mark, and the river starts to freeze. . Then come days of sleet and snow, when all the river boats are frozen in. All this time the water is slowly rising. Each day the weather grows colder until the thermometer reaches down toward twenty degrees below. Some- times the river freezes solid from shore toshore. The rising water loosens the ice, and then the ice lets go in huge Barges are dragged away from their moorings, carried down the river, and sunk. Boats are torn to pieces; others are picked up, carried down the river, and sunk. The ice shows no favoritism. Im- sissippi River Grind Helpless Ships: a This barge was nestling comfort- ably in. its bunk ' at Cairo, Miss., when along came the ice and whisked it away to Norfolk. These barges, which succeeded in running the gauntlet, emerged from the struggle sadly dilapidated portant government boats receive the same treatment as -ug-boats. One winter four large packet-boats, worth half a million dollars, were sunk in five minutes. This riot usually lasts for several weeks. When, finally, its energy is spent and the ice calms down, the river is full of wreckage. Some half- sunk boats are floated again, and some of the barges are saved; but so many ‘boats are a total loss that this ice spree costs the owners. more-than ‘a million dollars each year. There seems at present to be no way of protecting shipping from the fury of the ice. Putting the Motorcycle on Skates MOTOR-WHEEL for skaters, invented by Thomas Avoscan, a citizen of Switzerland, enables lovers of skating and motorcycling to com- bine the two sports, and to enjoy ~ both at the same time. The inven- tion consists of a tubular frame with an engine-driven wheel at one end, and a sled with a single runner sup- porting a seat at the otherend. The drive-wheel has projections on its tire to give it a firmer grip on theice. A gasoline or other engine may be used to supply the power. The rider sits on the seat attached to the runner at the rear end of the frame, and rides on the ice or snow, or he detaches the seat and, standing on the skates, lets the drive-wheel © pull or push him over the ice. The ‘handle-bars . for steering the ‘wheel are at the rear end of the frame and the turning mo-;_ tion is transmitted to the fork of the wheel-frame by a cable or chain wound around pulleys. Two pairs of handles, placed back to back, are provided. One pair, with the handles bent downward, is in- terided to be used when the seat on the runner is occupied; the other pair, with longer arms placed in a horizontal position, is used when the skates are in use. When the runner is not used, the rod to which it is attached may be folded, together with the runner, so as to rest on the horizontal top of the frame. When the skating seat is used, the operator rests his feet on foot- rests provided at the lower end of the brace-rod. These rests have down- ward extensions at their free ends by which the rear part of the frame is supported when the engine is not running. ’ One of the mechanical features of this invention is apt to confuse persons who are. accustomed to riding bicycles. In steering, the wheel turns in a direction opposite to that in which the handle-bars are turned. The inventor claims that this is desirable to obtain the best results in skating. To produce this effect he has provided a crossing of the steering cable between the pulleys.

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me + ee 7 Popular Science Monthly All Sorts of Johnnies Will Come Marching Home It wasn’t an exclusive war. Among . the Hun-hunters were these Egyp- ; tians who have gathered about the oo regimental scribe for the purpose of sending the good news home e / From India — which, despite German propa- ganda, was loyal— came some splendid - scrappers.to make things lively on the French front. In the intervals. of fighting the Indians were great card-players; butitis. ~ « "4 said that pinochle is- wo not their favorite game = Sis China represented the: far East on the Western front with sturdy labor brigades. These pig-tailless citizens of the republic are watching a dragon fight that has been staged by their leaders '™! Little Portugal didn’t con- ‘’ sider her treaty with Eng- “™ land ‘a scrap of paper,” but , gia rather as good reason for a y =+*% scrap with the Hun. Her ri b>. soldiers made excellent bomb- ers, as Fritz will admit South Africa, ‘sent: colored as well as white pildiics: The: huskies in | the* picture, both white and black, belong “to “a native Red Cross Koupltal corps Lo, the fighting Indian! When these original Americans took the war-path against-the ‘Kaiser, they proved to be invaluable scouts and most daring trench raiders oe

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January, 1919

While the Armistice: Is On

British official photograph Our Ally from the East shows his idea of a ‘‘standardized”’ ship “From Berlin to Paris,”’ said the sign on this German made merry- se go-round, but its French captors made the sign read ‘the other way —— : ——. 5 eee

**Merrily he rows along, ; ; He paddles his home made canoe Rows along, rows along!”’ od Saat : ; while Foch lays down his terms An old motorcycle engine furnishes the power for this trench-made scenic railway built by some Canadians ©Underwood & Underwood With characteristic Yankee ingenuity, he has made a comfortable cot out of materials salvaged from the scrap heap —<—— © Interna- tional Film “© Kadel & Herbert

Let’s hope that this soldier’s home- made ’cello makes music “that hath charms to soothe: the savage breast” 57

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<Af the thermostat balks,-or when there is no thermostat, the - driver-can regulate the amount of air for cooling the engine ‘How to Control the Temperature of Air-Cooled Engines T is essential for the proper working of an air-cooled automobile engine to maintain a nearly even tempera- ture. Obviously in zero weather less air will have to cir- culate around the engine to keep it cool than on a hot day. A recent addition to the large number of devices for con- trolling the air intake is one patented by Leslie W. Gris- wold, of Cooper, Ia. The inventor provides for two sets of shutters similiar to the familiar window-shut- ter. One set is in front of the engine-hood, the other underneath, near the front end. The shutters are controlled by rod con- nections with a thermostat, which is mounted on one of the engine cylinders and operated by the heat of the en- gine. Both sets of shutters can also be opened, closed, or set at any de- - sired angle independently or jointly by hand. For that purpose a handle with a locking device is provided, which is operated from the driver’s ‘seat through an opening in the dash- board. Each set of shutters is con- trolled by a different motion of the hand-control. Return steam line Air dome Locomotive. type” — air pump

Popular Science Monthly How Yankee Ingenuity Built Roads in : Devastated France HEN the American troops arrived in France, they found the military roads near the front in a deplor- able condition and entirely inadequate for the safe and rapid transportation of troops and war materials. It be- came one of first important tasks of the American engineer troops to build new roads and to repair those already in existence. The rapidity with which the Americans built substantial roads and the thoroughness of their work surprised even the French, who are noted for their road-building. But our engineers had at their command the best labor-saving machinery for road-building. One of these labor-saving devices is shown in the pictures below. It is an apparatus for distributing liquid asphalt for binding purposes over newly finished roads. The apparatus is mounted in a unit on a special frame which fits over the frame of an automobile truck, and which can be removed as an integral unit in one hour by unscrew- ing the nuts of sixteen bolts which fasten the frame to the - chassis. The asphalt is carried in a big tank holding 1000 gallons, and is melted and kept in a liquid condition by a system of pipes through which steam, generated in a steam-boiler located at the rear end of the truck, is forced. Some of the steam generated in the steam-boiler is used to operate a locomotive air-pump at the front of the tank. The air compressed by this pump is fed directly into the tank, and supplies a pressure of one hundred pounds to the square inch. By this pressure the asphalt, which is constantly kept at a temperature of from 150° to 200°, is forced through the nozzles of the sprayer in the rear and Gistributed over a wide strip of. the road-bed. The air-pump ‘is so arranged that by the changing of a few valves it becomes a vacuum-pump. By ex- hausting the air from the tank the melted asphalt is sucked into the tank. This is an important feature in view of the great viscosity of the asphaltum and the difficulty of charging the tank with that bituminous substance in any . other way.

pele se r One of these asphalt- spraying machines greatly expedited the building of. mili- tary roads in France a OE om”

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wr woovCU! we aS ea Oe — ye -) > Gg °F —— 8s eee @ ie Patrice EE January, 1919 You can ferry your car easily across the stream, but what about the car felliciaiaa ad A Ferry Driven by the Automobile It Carries HE problem of crossing a deep body of water in an automobile has been solved in a novel manner by L. B. Robbins, of Harwich, Mass. His device makes it possible to run the automobile: on.a specially constructed pontoon raft, and to drive and steer it across the water by utilizing the power of the car. The ferry consists of a platform of timbers resting upon two pontoons placed: parallel with each other at a distance greater than the width of the average automobile. ' The platform is provided with a rectangular opening between the pontoons in which the driving mech- anism is. placed. Two sets of rollers, mounted on parallel shafts, are placed underneath the platform so. that the circumference of the rollers is on a level with the platform. The forward set of rollers has mounted on its shaft. a small bevel ‘gear which meshes with a larger bevel gear mounted on the end of a‘shaft at right ‘angles to the rollers. This ‘shaft extends Senbnad in a slanting position under. the surface of the water, and has a propeller at its submerged end. In operating the ferry, the auto- mobile is run on the platform between guide rails, until the rear wheels rest upon the two sets of rollers. The motion of the rear wheels is transmit- ted by the rollers and the bevel gear- ing to the propeller; supplying the power for driving the ferry across the water. The steering device i is equally simple and clever. A rod of suitable length is strapped tothe front wheels of the car. To the ends of the rod are attached ropes, wires, or cables. running over pulleys to the stern end of the ferry, where they are fastened to the tiller. By turning. the front wheels of the car the tiller is moved and the ferry steered as desired. The inventor has, cleverly provided for everything—except the return of the ferry to its starting-point. Perhaps he has faith that there will always be a customer on the other bank, ready to supply the motive power for the trip back. Removing One of the Winter Worries of Car-Owners HEN the temperature outside threatens to drop to the freezing-point, the automobile owner usually begins to worry. and to have unpleasant. visions of frozen engines -and pipes circuit, to be started again after a predetermined interval. Unless the cold is extremely intense, a running of the en- gine for one or two minutes, ‘at intervals of from five to and of large bills for: re- pairs. ms An invention that was re- cently patented: by. George C. Olmsted, a citizen of Minneapolis, Minn., sug- gests a possible solution of the problem by providing an automatic device which be- comes operative when ever the outside temperature drops below ‘the freezing- point. The engine is started, and allowed to.run a few minutes, until it is:warmed up. Then it is automati- cally stopped by the breaking of an electrical EXHAUST - OPERATED ELECTRIC CLOCK- CONTROLLED CUT-OUT SWITCH SELF STARTER CUT-GQUT *S5WITCH re ADJUSTADLE CIRCUIT-CLOSER fi 2 CLOCK “CONTROME D MAGAETO CIRCULT If your automobile is equipped with this device, even below-zero weather need not cause you any worry 59 THERMOSTAT CIRCUIT-CLOSER. / * 7 STORAGE BATTERY? ten minutes, will result in kéeping the water in the radiator and cylinder jackets from freezing. “Tr addition to the storage battery, an auxiliary bat- tery is also required. The starting and stopping of the engine at predeter- mined intervals is con- trolled automatically by a clock-operated’ disk ‘of in- sulating mateérial, which has on its surface several con- ~-eentrically © “arranged: series ~ of spaced contact points. . These points periodically | engage a contact arm, thereby opening or closing the circuit.

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’ of the airplane. In the Ameri- Thissimple-look- ing apparatus makes the un- breathable air of a 20,000-foot altitude possible to inhale. The tube is attached to a bott'e con- taining oxygen How Aviators Get Oxygen at High Altitudes HE mechanical difficulties that in the early days of aviation prevented the reaching of heights as great as 15,000 or even 20,000 feet were overcome; but another difficulty had to be solved before sueh ascensions became practicable. At extreme heights, especially after a rapid ascent, the human lungs do not function properly. They cannot adapt themselves to the sudden change of air ¢ pressure, and the aviator is threatened with suffocation. But this difficulty also was overcome. Each aviator was provided with an extra supply of oxygen upon which he could draw in case of need.. The apparatus consists of an Arsonval vacuum bottle enclosed in a metal basket. The bottle is filled with enough liquid oxygen for two persons for one hour at a height of 15,000 feet. When the stop-cock is opened the oxygen passes in gaseous form through ‘a tube con- nected with the bottle. The cold produced by the evapora- tion of the liquid gas is so intense that the gas, if breathed in as it comes from the bottle, would congest the lungs and cause death. To make it Ereath- able it. is first’ conducted through a a long pipe: coiled around the basket) the Arsonval containing the*bottle, and then into a vacuum -bottle rubber bag; from which a tube conveys the gas to-the aviator. A second coil, with a rubber bag and serviee tube; is provided for the use of the passenger. There is no danger of an explosion should the bottle containing the liquid oxygen be struck by a projectile; but the héat from the burning of the airplane would be disastrous. . It would. cause the gas to expand and burst the container, and the liberated oxygen would aid in destroy- ing the airplane. The entire equipment for two persons weighs only about eighteen pounds and occupies but little space in the fuselage

can army it. has recently been ordered: that_every. pilot who - goes aloft must < carry enoughox- ygen forfrom six toeight hours. How necessary oxygen is to an aviator was demonstrated by the experience of Captain R. W. Schroeder, U.S. A., on his remarkable flight of Sep- — tember .18, 1918, when- he broke all altitude records by ascending to a height of 28,900 feet. There are four men in the pic- ture, but only one of them -is neces- satfy~ to operate the bale-extractor Popular Science Monthly Playing Jackstraws with Bales of Cotton MAGINE playing the game of jack-straws with bales of cotton weighing 500 pounds each. That game is played daily on a large scale at the New Orleans public cotton warehouse, which has a storage capacity of 200,000 bales, The bales are stacked like bricks in a wall on both sides of wide aisles. Some of the stacks are twenty bales high, and each bale is carefully labeled or tagged, the tag giving the identification number, locality, name of sender, and other information. Suppose that a certain bale of cotton—which may be at the bottom or somewhere in the middle of a twenty-high stack—is sold. It must be removed without disturbing the bales above, below, and on each side of it. Formerly it required five or six men and half an hour of time to extract a bale from the stack. Now the same work is done by two men in about.three minutes, with the assistance of a special device. This bale-extractor has an A-shaped steel frame with two feet, which are planted against the bales to the right and to the left of the bale to be extracted. Two long arms, curved like those of ice- tongs, are pushed between the bales; the bale to be taken out is grappled by them; and then the bale i is extracted from the pile by pulling on a rope or cable which runs over the pulley at the apex of the A-frame and draws hooks and bale toward the top of the A, the feet of which rest against the adjoining bales. The extractor can be operated by a single man. After the bale is removed, the traveling crane, suspended from the ceiling and operated by an engineer, picks it up and carries it to the loading-place.

The man in the {7% box of the travel-. 47 ing crane con- |; trols the power required for ex- tracting the bales

Jar

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January, 1919 Real Flying Dutchmen Mammoth air-boats that are at home in air and water HE first man who gave really seri- ous thought to flying across the Atlan- - tic—serious in the sense that he actually built a flying-machine to carry out his intentions—was Glenn H. Curtiss. He decided that his machine must have an enormous radius of action, and to obtain it he considered it necessary not only to increase the size of the airplane, but also to improve its efficiency. The chief obstacle to an increase of its efficiency was the landing gear. The sheer weight and air resistance ‘of that appendage wasted fuel. But when Curtiss considered the crew, particularly their comfort and safety, he went to the other extreme, and de- cided to turn the landing gear into a _ vessel as big as a sea-going launch. The boat or launch proved to be so heavy that before the machine could _ get into the air it was found neces- sary to leave behind most of the fuel. Later he adopted, the ‘“‘sea-sled’’ type of boat. While Curtiss was still ex- perimenting the world war broke out. He sold his experimental craft—the America—to the British Government,. which'.used -it.\very successfully in- patrolling the waters around the British Isles. ‘Ctirtiss gave to the world a craft that had.some of the attributes of both airplane and dirigible, alternately | The leviathans of air and sea lying in harbor. “the ‘picturesque high-pooped galleons of Columbus’s time 61 By Carl Dienstbach flying and resting on the water. Small flying-boats cannot live on the ocean, and to become relatively seaworthy, seaplanes’ must have sealed catamaran floats, and the men must be raised high above the waves. Only a mammoth craft, something with a huge hull, something that will transform the flying-boat into a flying galleon, can solve the problem. These huge flying galleons, as war progress has finally shaped them, rival in beauty the’ most picturesque old- fashioned ships. With their wings suggesting low-rigged ancient sails, they resemble the pigmy vessels in which the daring pioneer navigators of the fifteenth and sixteenth centuries crossed the Atlantic. Every structure becomes beautiful when once it is per- fectly adapted to its purpose. These new flying-boats are beautiful for the very feature that makes them prac- tical—their raised tails. What is it that an oarsman must know before he can safely venture out upon a big body of water? That he must cut the waves. Our galleons of the air are dirigible floating weather-cocks. From their rounded compact hulls waves dash off as harmlessly as from the caravels of Columbus or from Hudson’s — Half- C- aeae ag In action! ‘The flying-boat pro ed no mean adversary for the submarine Moon. They head into the wind as ~ quickly as .a high-forecastled, high- pooped ship of old, which was likewise a floating weather-vane. Their high tails, when they rest .cn the water, head them into the teeth of the wind. If the descent is too steep, the nose may be tilted up, yet the high tail drop clear of the water without splash- ing and without breakage. Alighting is a more delicate operation in a sea- plane than in a landplane. It is only too easy to come down nose first. Let the pilot beware lest. the prow be caught in the water and the machine turn a somersault. It certainly seems .a most interest- ing coincidence that ships that in truth navigate alternately the sea and sky have now assumed the identical and fascinating appearance of the legendary Flying Dutchman. They suggest | 4 d

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Popular Science M onthly Jani Do It with Tools and Machines Screw-thread leads may be accurately gaged with the tool post shown below Milling attachment for the lathe tool post to cut threads of any pité¢h A universal angle fixture to assist the workman at the milling machine and shaper With the use of these adjust- able pliers inaccessible places may be reached. Below are shown the pliers in detail A power hammer for use in shaping sheet ft metal to be used on automobile bodies A pair of adjustable tongs for the use of two men in handling heavy car axles ” FLEXIBLE | In doing odd jobs about a ™ garage oxy-acetylene tanks must be hauled from place With this electric machine a molder’s to place. The truck here / With this _corner .staying machine for helper can riddle foundry sand to the shown is~ especially - de- paper-box making a safety device under PERFO! amount usually handled by ten men — signed for carrying the tanks the anvil positively eliminates accidents Thi 62 “ suc

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gine oe Pre 9 Laeger Ee January, 1919 t - for the Housekeeper : " F = Ses. ea This. baking-pan has depressions for baking A heater to keep the baby warm in corn bread in the shape of an ear of corn bed or in its carriage on a cold day Making Things Easier A tray that can be clamp The adjustable shelf on ed to the base of a syrup the baker at the right in- jar, for the purpose of sures baking food under- catching the drippings neath as well as on top . This strainer can be adjusted without touching the strainer with the hands ‘A latch attachment for locking a door with a padlock: adaptable for - a barn or shed door The hour-glass used for timing the boiling of eggs is here adapted to use as a telephone timer ” FLEXIBLE. SHAFT z) STRAINER VBR ROTARY BRUSH PERFORATIONS DUST BAG f i This rotary brush combined with a vacuum A special sewing-machine attachment suction is used in cleaning seat cushions which darns fine hosiery very satisfactorily 63 A diminutive hand wash- board, which may be used in washing laces; ‘hosiery and’ other. small: articles: ; A bicycle trouser guard mi ps and a thick pin-cushion > make a conyenient place sti for: this: tailor’s needles erat a An attachment for keeping scissors in a convenient position for picking up

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Popular Science M onthy Righting the Capsized * ‘St. Paul” She is about twice as heavy as any other ship his r aa rat Big bc ea THEN the 13,000-ton American VV" liner St, Paul. turned’ turtle ‘‘ather dockin New York, she settled down fourteen feet into the mud, with her topsides only fifteen feet above the water at low tide. ‘Imagine this huge timber, 535 feet long, 63.feet wide, and approximately 80 feet high, lying on its side in forty feet of water. If the ship had been a timber of homogeneous mass and strength, it ‘would have been a neat engineering job ‘to turn it over; but the fact that it was -a ship, with all its rigging super- ~strueture, hatches, portholes, and ¥. jheavy weights of engines and boilers “concentrated at ‘particular -points “in “thé hull; made the successful comple- nvafethe task one of. the. most*re-

Lao turning | over. on her side,. 16 St, - Paul’s masts.antstacks ‘and some of. her ~ superstructure was crumpled-up in a tangled mass like so much paper and Stacks. This, of course, had.to be re- “moved before any of the actual salvage operations could be begun. Then, there were the naval guns to be re- moved while the floating operations were under way. To remove the rifles ~ on that portion of the deck out of «water. was:a simple task, but that of gettin “out. those which had their anrels Besides closing up all of the ports . and openings ..through - which . water and silt ‘could: enter the hull, it was necessary for the divers to make new openings in bulkheads and the like in order to facilitate pumping out the water later on. In some cases, these apertures were made by means of electrically igniting sticks of dynamite placed at the proper locations by the divers, While this method was cer- tain in results, it was not entirely satisfactory in that many of -the ad- jacent ship members and plates were damaged, and to be repaired. To offset troubles of this kind, Ralph E. Chapman, the salvage engineer in ‘charge, and J. W. Kirk, the machinist foreman,” developed an under-water oxy-acetylene flame device which can be employed while entirely submerged. $$

pinta tatty eee ee} 21 A- FRAMES

21 U-PART =~ BLOCK ‘AND FALL WIRE CABLES ; t

21 HOISTING ENGINES ANCHOR, LINES how. tackles-. attached to the A- fame “pe “while cables from the pon- . to tum the St. Paul —_— = : that | has been rescued from a similar fate In addition to cutting openings in some ship members to facilitate the flow of water once the pumping opera- tions were begun, it was found neces- sary to erect barriers in other parts ' of the ship in order to confine the water intended to be pumped out at any one time. Heavy concrete patches and walls were utilized for this work. Luckily, the boilers and the engines were found intact. The next step was to raise the vessel to a vertical position without moving her lengthwise, so that her bow or stern did not foul the dock piles fifty feet away. On account of her mass of thirteen thousand tons,”-it was evident that some new means would have to be resorted to in order to right her successfully. After much study, it, was decided to attempt: the work ° by 7 means of. block-and-falls. *.This is fully ‘described in the illustration on the opposite page. While both the A-frames and the pontoons were being placed, dredg- ing was being carried on at both sides of the hull where it tag: in the mud. Righting the V ae The righting operations by means of the pontoons and by pulling on the A-frames were not begun until July 22,.. although the boat sank on April 25, the long interval being due to the great amount of necessary preparatory * work. Once started, however, it took ~ | only six days to right the vessel from the original angle of 73 degrees. to which she sank, to 27 degrees, where ‘ the pontoons were no longer effective. The pontoons were then removed, and two cofferdams placed on the sides of the vessel amidships. These were necessary to prevent the water rushing into the hull, since the boat - was still resting on the mud and the high tide was above the decks. The next operation was performed by two large floating derricks, which took hold of the chains on the port side of the hull that had been previ- ously attached to the pontoons, and exerted a lifting and heéling force - while the pumps were removing * some of the water from within the .vessel’s hold. This work brought the ship to within sixteen degrees of the vertical, when the A-frames were removed, after which four floating derricks steadied the ship, while the pumps *¢ontinued their work until she floated free of the mud. ee

AONB O E

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Popular Science Monthly Nature Supplied the Material OR reasons best known to himself, a wealthy Cincinnati man desired to have built on his estate a log cabin, to be constructed, as far as possible, from the rough materials that nature provides. He got what he wanted— . Ynore or-less. “For about two years the builder assigned to the job wandered around the woods and shores, pluck- ing branches and gathering stones. When he looked over the accumu- lated material, he decided to build a three-room log cabin. The outside looks like a regula- tion log cabin much in need of a good finishing off—all except the chimney, which, right in its center, LO { ‘SS eee The second floor of a Cincinnati man log cabin, the exterior of which is shown above to 66 s “‘primitive’’ has a most puzzling hole. This turns out to be an entrance for the use of frisky ones who prefer that way of entering the house to the front door: They run the risk of being covered with soot, but then, there’s no account- ing for tastes. In the entrance-hall stands a de- cidedly rustic chair. A few trees are scattered around (one of them serving as a staircase support to the regions above); there is an ordinary glass window; and, lastly, a little electric Jight bulb nestling in the ceiling. Of. course the window and the electric light aren’t strictly in accord, but even naturalists must have some conveniences. _ As for the upper regions, they are distinguished by more windows, the chimney-door, another bulb, and some. young trees tacked onthe walls. For the artistic result, little can be said; artistic ideas vary with the individual. This is the entrance-hall, with a tree serving as the stairway. An electric bulb nestles in the ceiling Knock-Down Snow-Sheds to Protect Miles of Track NOCK-DOWN snow-sheds of con- crete construction are the latest thing in the railroad world. A bitter fight to keep the Union Pacific tracks clear started with the storm that be- gah December ‘20, 1916, and was pro- longed with increasing intensity through January and Within five minutes after a snow-plow had fought its way through the drifts, all of the labor would have to be done over again. For six weeks zero was the highest mark. Driving a rotary plow into one of these frozen drifts was like driving a motor-truck into a stone wall. : Tempo- rary snow-sheds were built, but it was evident that more substantial structures would have to be planned. As a result, new sheds were decided upon. Briefly, these sheds rest on con- crete piles or pedestals. A-framesserve — as braces on ’ February. The finely powdered show swept downward from the mountains, carried by a gale that often attained a ve- locity of sixty miles an hour. Whenever a train stopped for coal or water, the snow would pile up around the the sides. Rein- forced concrete girders serve as roof supports. Slabs of rein- forced concrete fill in the sides and form the roof. The piles were driven from fifteen to thirty feet. Because of their uniform construction, they can be wheels, block- ing the train. The A-frames are nine feet wide at the bottom. and twenty feet high. ‘The concrete slabs are 2% inches thick. Light is provided by omitting the top row of slabs on the leeward side 66 moved to any location desired, cot pense

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lO SOD. ee ae ee * ~ rr ec we FS: 8 January, 1919 HE ‘complexities and constantly changing character of the war, and the necessity for the rapid training of specialists in every branch of service, created an emergency in the matter of supplying text-books. Many subjects developed so fast that print could not keep up with them— for instance, aerial photography and camouflage. Army liaison, never be- fore employed on so large a scale, had been written of scarcely at all. The Library ‘War Service of the American Library Association engaged to. furnish any published technical work .or text-book that might be needed in‘ army camps, war schools '’ and colleges, or naval establishments, in this country or overseas. It could not very well furnish books that have never been written, but it could do the next best thing. It could furnish the technical and scientific data from which such text-books might be compiled. If, for in- stance, the latest work on camou- flage were hopelessly out of date, the Association would get to- gether all of the available books on animal protective coloring and __ color-photogra- phy. From reference books of similar value the army experts pre- pared their own text- books in mimeo- graphed form. Arts of Peace Applied to War Many of these ar- my text-books con- cerned the adaptation of familiar arts to army uses. A book on motorcycles that was prepared at Camp Joseph E. Johnston, Florida, included ‘a complete manual of instruction for the convenience of despatch riders, with The boxes used. for shipping books over- seas are provided with a shelf, so that they can be set up like a sectional bookcase ganization of motorcycle companies in the field. Sit, In a whole library on the subject of printing there exists no book especially designed to fit the needs of army printers. War and the army have a nomen- clature all their own, with scores of abbreviations unfamiliar to civil workers. An army print-shop is dif- ferent from an ordinary composing- room. The printer had to learn the etiquette of war. for example, exactly in what type to set a. general order, and: by whose authority an officer may have his name and telephone number on a letter-head. ~~ When the libraries were first planned, He had to know, a a Minds as Sharp as Bayonets - How the Library War Service provides for the education of our fighting men it was thought they would be used chiefly for recreation. It was found that the most regular readers used them for study purposes. This meant a rapid reorganization of the book collections, involving the purchase of 600,000 technical and military books. Gift books to the number of 2,600,000 volumes, the donations of the public—largely in the classes of fiction, poetry, history, biography, and travel—were also placed in service. Distributor of Literature to the Army and Naoy Enormous quantities of the’ “Burle- son’? magazines are used in barracks, hospitals, recreation huts, and on troop trains. The sorting of these magazines entails considerable labor, for men in camps are very like men outside— they want new magazines. Millions of these gift magazines were distrib- uted, and the American’ Library Asso- ciation also entered subscriptions for eleven magazines to be supplied to all Y.M.C.A. and K.of C: huts where reading facilities are provided, as well as to the libraries proper. These magazines did much to supplement books in providing up-to-the-minute information on technical topics that were still in a state of flux. Arrangements were made with both Admiral Sims and General Pershing whereby the American Library Association became the official distributor of ‘literature to Americans overseas, and fifty tons free cargo space was allotted each month for books for our boys. Thousands of refer- ence works and text- books were furnished to the army and navy by the Ameri- can Library | Asso- ‘ciation, but many more are needed. There are constant ealls for books on mathematics — arith- metics, trigonom- etries, and geometries. Most of these books had to be purchased, but some were do- nated. For the first time in history, the intel- very complete chap- ters on the personnel, equipment, and or- This library interior at Camp Jackson is typic 67 al of the buildings which the American Library Association erected in every large camp. In the oval above—Navy boys studying eleciricity take their library books to the switchboard, in order to combine theory with practice lectual needs of a great fighting force were scientifically considered and met.

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Once installed, this system of house-heating with kerosene continues to. function without requiring further attention. The descriptions on the picture explain the details of the apparatus used in this heating system You Can’t Get Coal? Heat Your House with Kerosene HE difficulty of obtaining coal has induced many house-owners and manufacturing concerns to sub- stitute kerosene. The system of house- heating with kerosene is easily installed in any house equipped with a steam or hot-air furnace. Aside from the re- moval of the grate bars, no change is necessary in‘ the furnace. Any good mechanic can install the system in a few hours. The apparatus consists of a kerosene- tank connected by a narrow feed-pipe with the combustion-chamber, a mo- tor-driven blower which atomizes the oil and blows the spray into the combustion-chamber, a pilot light to ignite the oil spray, and a. thermostat for regulating the fire according to the desired temperature. .When the tem- perature of the room reaches the point at which the thermo- stat is set to operate, the elec- - tric circuit to the motor is broken, so that the blower stops feeding fuel into the com- bustion-chamber and the fire goes out. When the room temperature drops and the thermostat again makes the electric contact to the motor, the fuel is ignited by the small pilot light in _ the botton of the combustion- chamber. This methodof using kerosene instead of coal as a fuel in house-heat- ing .plants undoubtedly offers many advantages. It is much cleaner than coal, and, once it is installed and set in operation, requires practically no attention. There is no smoke, soot, or waste, no ashes to be removed, and the temperature is regulated automat- ically. But the system is not econom- ical. The cost is as great, prob- ably greater, than the cost of coal. Another drawback lies in the fact that electric current is required to drive the motor and ‘illuminating gas for the pilot ‘light. A SHUTTERS 68 RADIATOK =, Popular Science Monthly Making the Radiator Easy to Look At OR the benefit of fastidious per- sons who object to radiators because they disturb the artistic harmony of beautifully furnished rooms, a Western manufacturer has placed on the market an imita- tion woodwork cabinet for disguising the naked ugliness of steam radia- tors. It is a sort of artistic camou- flage that in no way interferes with the usefulness of the heaters. These cabinets, which are made to order on any style, are of heat- insulated metal, painted to imitate the color and grain of any kind of wood desired. The cabinet is open at the bottom and is placed over the radiator. The cold air from the room enters at the bottom, is heated by the hot steam coils, and passes out into the room through a series of grilled openings near the top of the cabinet. The slits are provided with shut- ters, which are connected by a bar with the operating arm of a thermostat installed in a specially provided chamber at one end of the cabinet. The thermostat may be set for any temperature desired, and when that limit is reached it will auto- matically close the shutters of the slits through which the hot air passes into the room. The thermo- stat is operated by the expansion and contraction of an air-tight copper or brass cylinder with corrugated, bel- lows-like sides. The bellows movement of the cylinder is transmitted by an in- genious system of levers to the rod, which controls the shutters and causes it to open or shut the slits automatically. e YOKE FOR BAR, TO SHUTTERS, ADJUSTING » pol... pamaie ADJUSTING BAR AND SPRING ae | "a You may artistically camou- flage your radiator by cover- ing it with a cabinet. The thermostat inside the cabinet will automatically regulate the temperature of the room

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January, 1919 Energy—Fuel A pile of anthracite coal-dust which is being used in a new composition fuel. The coal is just as it comes from the mine dumps without grinding cr crushing. The particles vary in size. It is mixed with a liquid that is a by-product of illuminating gas Save the Nation’s Learn how to handle f your furnace and save coal and doctors’ bills By A. M. Jungmann - . the desert of eral health and freedom from colds this winter—save coal. A quart of water evaporated in every room of your house every [ you want to enjoy better gen- day will mean a saving of one third of your coal bill. What we really need in our houses is hu- midity rather than a high degree of heat. Moist air feels warmer than dry air of the same temperature, and moist air has the further ad- vantage of retaining heat. Professor Ellsworth Huntington, of Yale University, recently made a study of some nine million deaths in all parts of the United States and in France, Italy, and Japan. He also made a survey of fifty mil- lion deaths in Belgium, Great Brit- ain, Germany, Russia, Rumania, Spain, and other countries, bringing his investigations of deaths up to the staggering number of sixty million. His study has resulted in the conclu- sion that an average temperature of 64° F. is the best for the maintenance of health. Professor Huntington also found that a uniform temperature is not so healthful as a variable temperature. He con- cludes that a frequent fall of — temperature, followed by a more gradual rise, is an excellent means of preserving health. Do Not Heat Sleeping-Rooms Persons who desire mental and physical vigor should sleep during the winter in rooms in which the temperature ranges from freezing to 40° or 50°. It is not necessary for sleeping- rooms to be warmer than 50° at-any time of the day. Win- dows always should be partly open at night and Suaue of fresh air ad- mitted to bed- rooms. The reason Sng people keep ‘, their houses at Fe sucha high tem- perature in win- ter is that the outside air, after it is brought into the house and warmed, usually be- comes as dry as Sahara. This dry air feels colder at 70° than moist air would at 60°. water in your house you can save coal because it will not be necessary to keep the air at such high temperatures. If you are using a steam or hot-water heating appara- tus, keep a pan of water on every radiator. The composition fuel in use. floor in front of the boiler shows freedom from The ash on the . Clinker and a_ free-burned: granular condition The U.S. S. Gem, which has been used to test different types of fuel; she has made many successful trips operating on pulverized coal 69 | ’ | By arranging to evaporate These pans should be provided with wicks. There are on the market valves to be attached to steam radia- tors, which play moisture into the air of the room. If you use a stove, keep a pan of water on top; and if you heat your house by a hot-air furnace, keep a pan of water in the drum, so that the moisture will pass- up with the heated air. Experiments in Ventilation Professor C. A. E. Winslow, also of Yale University, con- ducted some very interesting experiments in ventilation for the New - York State Ventila- , tion Commis- sion. He found that the latest methods of ven- tilating rooms by taking air into the cellar, warming it to a temperature of about 67°, and blowing it into the rooms by fans was not so healthful as the ordinary procedure of

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wa ‘have in other years. ‘was a blessing in disguise. on who is tending the furnace keeping the rooms at the same average temperature but ventilat- ing them by letting fresh air in at. the windows. In the modern system of ventilation the tem- perature did not vary and there were no drafts. Yet people who worked in’ rooms. under these conditions suffered from colds to a greater extent than those who worked in the rooms where the temperature varied. Although December and Janu- ary of last year were unusually cold, the death-rate was low. This probably was caused by the fact that people did not keep their houses heated as much as they Shortage of coal, instead of being a hardship, Experts in the Bureau of Mines have made some suggestions on as to how to burn coal economically at home: First of-all, they lay stress upon the fact that the per- ~ the Popular Science Monthly If you will put weather-strips around your windows, the saving in coal will amount to many times their cost Be sure the glass in your windows is tight. A little trouble in puttying the window-panes will save _ coal must acquaint himself very thor- oughly with the apparatus. If you want to burn the coal faster, supply more air through the grate. More air can be supplied by open- ing the damper in the pipe leading to the chimney, by opening the damper in the ash-pit door, or by shaking the ashes down from the grate. If you want the coal to burn more slowly, reduce the draft by closing the chimney damper or the damper in the ash-pit door. Learn to Manage Your Furnace To increase the supply of air over the fuel-bed, open the damper to the chimney or the damper in the firing door or both. Air in- troduced over the fuel-bed helps in burning the gases and the visible smoke rising from the burning fuel. In order to be really economical, you must study your furnace and find out just how much air it requires; for too much air is as wasteful as too little. A heavy fuel-bed generally gives more satisfactory results than a light fuel-bed, because, during the long periods between firing, a light fuel-bed is apt to burn down too much. When burning bituminous coal it is better to place the fresh coal somewhat in a heap to. one side of the grate and leave a small part of the burning fuel uncovered. If the coal contains a large percentage of slack, this method of firing is particularly satisfactory, because the coal is heated gradually and the volatile matter distils slowly and is given a chance to burn. Before the next firing the coked heap of fuel should be broken and spread over the grate. A new charge is then placed on the opposite side of the furnace. FL MLE BEE EEE EEA MER IE BE: BE bigs OE To prevent cold air leaking into the house, calk the doors with an elastic substance that vibration will not effect Mercer P. Moseley, Chief of Con- servation, has compiled a list of “don’ts” for coal-users. If you ob- serve these rules you will be able to effect an appreciable saving in coal: Don’t fail to clean furnace before start- ing fire. Don’t build a fire until necessary. Don’t build a fire larger than is necessary. Don’t fail to make check-draft damper in smoke-pipe do its work. Don’t neglect keeping fresh water in your steam-heater boiler. Don’t fail to keep your kitchen stove clean. Don’t keep your home at over 68° F. Don’t leave your draft open at night. Don’t try to heat all of outdoors. Don’t keep your fire going on pleasant days. Don’t sit in north room when the sun heats the south side. Don’t think it’s fur-coat weather when the thermometer is 45° to 50°. 70 If your total coal consumption is fif- teen tons a year, you can save at least three tons by insulating the pipes Don’t waste water—it takes coal to heat it. Don’t forget that one gas-jet will raise the temperature of a room five degrees. Don’t fail to put up storm doors and win- dows. Don’t fail to sift ashes. Don’t burn coal when wood is available. Don’t fail to wrap your pipes with asbestos. Don’t fail to keep rooms moist—they heat easier. Don’t forget that moist air retains heat. Don’t forget that dry air causes colds and catarrh. Don’t waste gas—it is made from coal. How to Bank the Furnace Do not let your fire burn too low before banking for the night, because it.may go out after banking. When banking the fire, leave a part of the surface of the fuel-bed uncovered in order to prevent explosion of the gases rising from the banked fuel. The regulation of dampers after banking Se SSeS Ss ee ony oaoctees BDBweoRe wad

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January, 1919 = a at ae a i ah y i baffles are in good order, that the boiler-tubes are not full. of soot, and that the flues are air- tight, and everything ship-shape. A leaky flue will cause the burn- ing of more coal than is necessary. Wherever possible avoid turns in your flues. The ideal flues are short and straight. Flues that have turns offer resistance to es- caping gases and do not afford the free draft necessary to satis- factory combustion of coal. Pulverized Coal Pulverized coal is solving many fuel problems. The ideal condi- tion in which to burn coal is pulverized. With pulverized coal there can be no clinkers and no smoke, and the combustion is complete. Pulverized coal is ground so fine that a pinch of it between the fingers dogs not feel gritty. A cubic inch of coal is ground into such fine particles that 95 per cent. of it will pass through a sieve having 10,000 openings to the square inch. The advantage of pulverized coal will become ; apparent when you remember ; that a cubic:inch of. coal has a ; surface or superficial area of six square inches; but when it has been converted into these small particles its superficial area is in- creased some 700 times. This means that each one of the two million particles is surrounded by air and, when burned, permits perfect instantaneous combustion: There is no waste. Pulverized coal burns like gas. Not an Untried Fuel Pulverized coal is not an un- tried fuel. Nearly ten million tons i Hi Y 4 z g y 5 % ; } i g i § g § 5 y i SORA ANN Yi Mitt bld Examine the nails around your window- casing: if any have become loose, you -will save coal by tightening them Take the time to clean your flues out thor- oughly at least once a week; soot is a poorer conductor of heat than asbestos PALMAE ALAMLULEMMIUML HN Cttid hd Phat bohhd bad tttIhi hy Never allow the ashes to get within six in- ches of the grate; a full ash-pit cuts down the heating efficiency twenty per cent If the air enters from below, in burning soft coal, the oxygen is burned out; the cemedy is to let in air from above the fire depends on the amount of air that leaks into the ash-pit, and is something you must determine for yourself. It is generally wise to close the damper in the ash-pit door and leave the damper leading to the chim- ney partly open in order to prevent coal-gas getting into the house. Saving Coal in Industry The best way to start to save coal in boiler plants is to give up guess- work and apply scientific principles. The men who actually burn the coal should be trained in the principles of combustion. No matter how good a man’s intentions may be, he cannot save coal for you unless he knows how and knows why it is necessary for. him to do certain things in order to ac- complish the desired results. Although a very clever fireman may be able to tell you all about your fire by simply looking into the furnace, you cannot expect every man to dothat. The only way you can really know the con- dition of your fire is by using record- ing or indicating instruments. Accu- rate instruments, such as draft-gages, flow-meters, and pyrometers, will help you to handle your coal intelligently and economically. Some of the things to be guarded against in using coal are clouds of black smoke coming from the stack, which is always a sure indication of waste; the loss due to high percentage of carbon in the ash; and the wasting of exhaust steam. Your steam is a direct product of your coal. There is usually a great deal of economy in using mechanical stokers. Needless to say, it is necessary to see that your entire apparatus is in good condition, that the boilers are clean, that the 71 ‘of it are being used in the United States each year. In the manu- facture of cement six million tons are used; in the production of cop- per one and a half million tons; in the iron and steel industry, two million tons; in the generation of power, some two hundred thousand tons. Thecost of pulverizing coal isnot at all prohibitive. It can be prepared . at a cost of from sixty cents down to twenty centsaton. The coalis burned by projecting it into the furnace by means of an air-blast, forming a cloud of thoroughly mixed air and coal. Where scarcity of labor is a factor to be considered, pulverized coal is a very desirable form of fuel, because one man - can handle a number of machines; for the process of burning this form of fuel is almost entirely mechanical. Pulverized coal is not only suited to stationary plants, but is used with gratifying results on locomotives and steamships. Its use on locomotives

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is especially promising because of the saving of. both time and labor: Burning-pulverized coal on a locomotive does away with the necessity of afireman. The coal is‘supplied to the fire auto- tiatieally at the discretion of -- the. ‘etigineer.: “There is no smoke;--and -no. cinders ‘are ~~ pas “along the®-foad-bed. - Hen’ it-isconsideréd“that one - railroad ‘in “the United States 4 spent. in’ -1916°+$875;000"- in - ~~ settling claims for fires started by ‘sparks-or sburning ‘ashes along its right of way, you can: see’ what a “great ‘advantage. | pulverized coal-has over the ~ usual locomotive fuels-*" ©- °°: Used on Locomotives Locomotives operated on pulverized coal do not have to waste time at ash-pits or in cleaning fires and shak- ing grates. When the fire is extinguished there is no waste of combustible in the ash, for there is no ash. Inspection can be made very easily. - A series A square fire-pot fired by the coking method of tests show the advantages of pulver- ized coal for operating locomotives over ordinary coal. . A Mikado type of locomotive in a fast. freight service running over a 115-mile division consumed about 29,500 pounds of coal for six trips, as compared with another locomo- tive of the same type, equipped for burning pulverized coal, and which consumed 22,500 pounds of ‘coal, or a saving of 23.7 per cent in fuel, A Idcomotive burning pulverized coal has been in constant daily operation near. Fullerton, Pa., since January, 1918,’ and up to the present has not been. laid up for repairs. ae The Coal Situation This Year Experiments in burning pulverized coal were conducted within. the last few months on the U. S. S. Gem, and proved that, where a steamship had storage-room for that fuel, pulverized coal is eminently satisfactory for use in operating ships. The coal situation this year is particularly interesting. The coal year begins on April 4. The anthracite ¢—__. TURBO-~ SLOWER. AND AIR DUCT This is the apparatus that is used for burning pulverized coal on locomotives _CORMEYOR COMBUSTION CHAMBER COAL coal consunied for domestic purposes in 1916 was 49,258,000 tons. To this the Fuel Administration has added 2,000,000 tons, bringing the total to 51,258,000 tons, which it has under- taken to supply this year. The first half of the coal year was up on October 1; and the supply for that period was exceeded by 759,136 tons. Bituminous coal is produced greatly in excess of anthracite; about twelve times as much bituminous as anthracite coal is mined each year in this country. 72% A six-wheel saddle-tank locomotive equipped with a pulverized coal apparatus. It has been in daily operation in Pennsylvania since January 2, 1918. Popular Science Monthly Shortage of Labor in Mines This year the United States expects to pro- duce some 600,000,000 tons. In the first six months of this year’s coal year 37,000,000 more tons were mined than were pro- duced last year in the same period. ; Ever since the war began: we have been using an in- creased amount of bitumi- nous coal—an advance of some 50,000,000 tons for each year. When you consider the A round fire-pot fired by the coking method shortage of labor in. the mines, the production this, year is nothing short of remarkable. If we all do our bit, from turning off the gas or electric light when we leave a room at night, to inspecting the flues in our in- dustrial boiler plants to see that there is no leak, we ‘shall have enough coal this year to keep every- body warm enough for health’s sake and to keep the wheels of our re- construction industries not only turn- ing but humming. Coal capacity, one and a half tons serbian Re tio Ao aw tec de lor of shi the for der shi use rib ‘ has spi: shi) dev lau anc shi fro side anc sto: ass on pre shi; fun this gro ere vat

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ee ae peepee January, 1919 Making ibiemraise Invisible T was the visibility of the periscope, more than anything else, that made an effective war against German’ sub- marines possible. A periscope is useless if it is submerged. The part of the periscope tube that extends above the surface of the water is not more than about two inches in diameter—not much, but enough .for the vigilant watchers on the numerous patrol-boats that cruised in the danger zone. Various methods were tried to diminish the visibility of the periscope. At first they were painted in shades of blue or gray or green so as to make them blend with the color of the sea. were found to have but little protective value. Covering the tube with’ a green and violet checkerboard in some cases. A suggestion that’ is theoret- ically good pro- vides’ that the ‘tube of the per- ‘iscope be sur- ‘rounded by a series of conical ‘mirrors, which, when seen from a distance, blend with the back- ground because they reflect the ‘sea. A new idea in pro- tecting periscopes These HEN a sinking ship acquiresa list to port or to starboard, and the deck is correspondingly inclined, the Coating the tube with aluminum “paint- was also tried. But-all such attempts at camouflaging ~ proved effective A washing plant’ like this, operated by belts from the factory shafts, may’save’a great deal of money for the manufacturer ‘Don’t Waste Waste E have all been.taught to avoid the waste of money, words, -and advice; but who ever heard of wasting ‘waste? Yet, waste—that i is, the kind that is used to wipe clean machinery, printer’s type, etc.—may actually be “wasted. A Western manufacturing concern installed in its factory an experimental plant for reclaiming soiled waste and rags, and found that they could be washed from six to seventy- five times at an average cost of 14 cent a pound. The reclaiming equipment,. which consists of a washer, an ex- tractor, and a drying drum, is now manufactured and marketed by that same concern. Life-Boats May Be Launched from Either Side of the Ship outward in opposite directions there- from to wheel pulleys located at the ‘has recently in- long line of life-boats on the high side of the deck, all swung from the regula- tion type of davits, cannot be launched. The well known fact that sinking ships invariably get a list before the final plunge has been disregarded for years, ren- dering half the ship’s life-boats useless. This-ter- rible condition spired two Scotch ship-builders to devise means for launching any and all of the ship’s life - boats from the lower side of sinking ~ and listed ships. The boats are stored in a closely assembled group on a_boat-deck, preferably amid - ships adjacent the funnels. Above this concentrated } group of boats is. || erected an ele- vated steel struc- No matter how badly ture of athwartship extending I-beams, supported on steel columns, each equipped with a chain-hoist trolley for lifting the life-boats from the chocks. Hauling cables for moving the chain- hoisted boats to port or to starboard are attached to each trolley, and lead the sinking ship may list, it is possible to launch life-boats that are provided with this handling apparatus 73 end portions of the I-beams, and thence inward and down to a hand-operated winding-drum. The-ends of the athwartship extending I-beams are also equipped with boat falls and tackle like thoseon ordinary boat davits. Theoper- ation of “getting the boats.over’’ is, first, . to raise each boat in turn from its supporting chocks by ‘the chain-hoists. Then the wind- ing - drums aré operated to haul the suspended boat outward by ‘the trolley cables to the lower side of the leaning deck, and to the corresponding ends of the over- head I-beams. The final opera- tion of “lowering away’ the boat is performed by transferring the support — of . the . boat from~ the chain-hoists tothe falls and tackle.

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Exit the Zeppelin ‘Airship: Enter the Zeppelin Flier Out of failure of the dirigibles.: grew the largest of airplanes ‘By Carl Dienstbach ~ JF) OMBING planes “are Se Se weight-carriers. They must be able to fly for hours, which means that they must be able.to carry much fuel; they must. be able to do much damage, which means that they must be able to transport heavy bombs. It is fortunate that the weight of the crew does not increase proportionately with the size of the machine. The four men of a Handley-Page, for instance, could navigate a much larger craft. It is easier to state the principle than to carry ‘it-out. “There is no more difficult “engineering task than ‘the construction of a huge biplane. “The British deserve the credit of having developed the first big bombing plane —the Handley-Page. To be sure, the Russian Sikorsky—a machine even larger than the Handley-Page—was built before the war, but it failed to meet the test of war because the struc- tural problem had not been solved. Curtiss, in the United States, had also made experiments with large machines. But tho fact remains that the British evolved thefirst practical giant bomber. Bombing Zeppelins Abandoned When we consider the difficulty of building a huge bombing biplane, and the failures that greeted pre-war at- tempts with the Sikorsky and other big machines, it is no wonder that, when Germany determined to intimi- date England by bombing London and other British towns from the air, she rejoiced in-her Zeppelins. Their radius of action was well-nigh bound- less; they could elude early air defense artillery with ease. There was a rude awakening when, later in the war, one great dirigible after another became literally a flam- ‘ing altar on which a score of lives were sacrificed. good naval scout, but a vulnerable bomber. _When-it became apparent that the Zeppelin airship must be abandoned for bombing raids over Eng- land, the Germans copied the Handley- Page and produced their first Gotha. But Gothas did not take the place of Zeppelins; and the Germans gave orders for the construction of air- planes of startling dimensions. Aided by the Albatros works, the Zeppelin Company produced a giant bird which - marks a distinct’ advance. in the German officers at last. _ saw the truth. The Zeppelin’ was a devéiopinent of the” ‘long-range bombing airplane. The new craft’s. load of bombs is two tons, as against the Handley- Page's. half a ton. The span is 135 feet,'as against the Handley- Page’s 98; the length 94 feet, as against 65; horsepower 1200, as against 740. The speed remains what it was in the Zeppelin dirigible—75 miles an hour—against the Handley-Page’s 85. It is the general practice in large bombing planes to balance the eleva- tor and the ailerons, by which latter side-to-side balance is preserved: In other words, there is usually a bal- ancing surface in front of the pivot- shaft, the object being to make the operation. of the control surfaces as easy as possible. In the Zeppelin bomber there is no such attempt at balancing. The conclusion is inevita- ble that there must have been auxiliary engines (probably electric motors) to operate ailerons and elevator, although French engineers who reconstructed a wrecked machine are silent on that point. Inside of the wings is an intricate filigree-like wooden lattice-work which is designed to secure great strength with little weight or air resistance, and which reminds one of the be- wildering framing of-a Zeppelin dirigi- ble’s envelope. The spars are of hol- low girders. . All the other framing is of steel tubing. Wherever the tubes are exposed, so that they must be driven through the air (struts, etc.), they are encased in thin wooden shells admirably \stream-lined. The tail- framing, however, is of aluminum, for the reason that the tail, being farthest from the ‘center of gravity, must be extraordinarily responsive. How the. Zeppelin Was Copied It will be remembered that in the latest Zeppelin dirigibles the May- bach engines were enclosed in egg- shaped cars so as to reduce head-on resistance. In the biplane we find similar “‘eggs’’ in which the engines (Maybachs, of course) are housed, while the crew sits in a separate cen- tral car. But in the biplane each “egg’”’ contains two 300-horsepower engines, one behind the other. Examine the illustration on the op- ‘posite page and you will see that there are both pusher and tractor screws in 74 Popular Science Movithly tandem. This is indeed a bold de- parture from long accepted doctrines. Why did the Germans violate the rule? Because it was areal advantage to have four separate engines and four seperate propellers and only two engine-rooms. The air resistance of the engines is obviously reduced by half, and the weight of the engines can be brought nearer the center of the machine. Landing Twelve Tons at High Speed The greatest problem that confronts the designer of mammoth bombing biplanes is the provision of an adequate landing gear. Here, for instance, is a machine that weighs twelve tons, and that lands at a speed scarcely less than forty miles an hour. Imagine what that means. The. Zeppelin biplane’s most meritorious feature is its landing gear. Look at the picture op- posite. Note how low, sturdy, light, and devoid of drag is its extraordinarily simple framing. Note the wheels ar- ranged in groups offour. This mass of pneumatic tires efficiently supplement. the shock-absorbers. In a small machine a tail-plane such as that on the Zeppelin flier might lead to stalling. But a mammoth machine is free from any such danger. because of its momentum and its . Without the pecu-. multiple engines. liar tail the main landing gear would have to be very much higher, air-_ resisting, and ponderous. Because the landing gear is lowit becomes neces- sary to usefour propellers of small diam- eter in place of the two large propellers of the Handley-Page. These make it possible to lower the landing gear. Clearly, landing on such a gear offers anew problem. Unless the pilot comes down on nearly an even keel, the ma- chine’s nose strikes the ground at such an angle that the strain would be more than the front wheels could withstand. This difficulty has been met by the ingenious arrangement of the tail, in which the French engineers who reconstructed the machine before- mentioned failed to see anything but a puzzle. abe "RE LoTR REA NS ante ene SI

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To save fuel the furnace fire must be watched. But who wants to sit in a cellar all day? Here's an autpmatic device that watches the furnace for you A Furnace that Regulates Itself and Saves Coal COMMON cause of fuel wastage is lack of care in so regulating furnace fires that only the required heat and no more is produced. To exercise that care requires con- stant attention in feeding and regulating the furnace. But you can’t sit in the cellar all day long and watch the furnace. Thomas Connell, an Iowa inventor, comes to our assistance with an automatic regulator consisting of a little metal tank having two com- partments of unequal size. The larger of the compartments -is connected with the boiler by a pipe. Under pressure of steam in the boiler, the water in the larger compartment is forced into the smaller compartment, and rises to an outlet near the top, through which it enters a pipe pivoted at that point and extending in oppo- site directions. At one end is a slidable weight, at the other a box with an outlet at the top. The water, forced into the pipe, flows into the box, and the weight causes the box to descend. The box is so connected with the draft-door under the grate and with the damper in the flue- pipe that the draft is checked and the damper opened when the box drops, Just slip the ring-shaped vessel over the is camp-stove when you want hot water 76 Popular Science Monthly A Novel Anti-Freeze Pipe | TANK— DRAINING OUTLETS

PIPE- DRAINING if OUTLETS

DRAIN PIPE

OMETIMES it becomes necessary to stop the flow of water or other liquid from a tank and to drain the pipe to prevent freezing; or it may even be necessary to empty the tank. In the novel arrangement shown above, the portion of pipe within the tank is closed at the end, but has inlet holes that allow the liquid to flow through the piping when the nipple is not screwed in too far to the left. In the position shown in the illustration the tank outlets are closed by the nipple, which projects beyond them, while at the same time another set of holes are in the open position for draining the pipe. A slight movement of the nipple to the right or left will close all the drainage outlets, per- mitting the piping of the liquid to points desired. It can readily be seen that if the nipple is moved suffi- ciently far to the right a point-will be reached where not only the piping but the tank also will be drained. Thus this simple form of construction permits any one of three separate and distinct operations. The liquid may be ‘ piped from the tank, or the supply from the tank may be shut off and the pipe drained, or both tank and pipe may be emptied—all done by a simple twist of the wrist or the application of a wrench. How to Get Hot Water from Your ~Camp-Stove HEN Francis L. Alsobrook, of Alamo, Tenn., wants hot water, he uses his camp-stove. The stove is of conical shape, tapering toward the top, and ending in a detachable stovepipe for carrying off the smoke in the usual manner. A ring-shaped vessel of galvanized iron fits around the upper part of the stove. The water-heater (provided with a faucet) has a cover which fits around the stovepipe and has a spring friction catch by which it may be held in any position to which it is raised on the pipe. The water is filled into the heater from the top, after the cover has been lifted out of the way. When the heat- ing vessel is full of water, the lid is shut tight. ’ The stove may be provided with legs and a bottom, or it may be without legs. In that case, it is set on the ground and the fire is built under- neath. The stove has a door for putting in the fuel, prefer- ably wood, and another door underneath, for the removal of ashes. One of the best features of this stove is that it may be taken apart for moving; for the stovepipe comes out and the heating vessel comes off.

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ite Jan 0 "geen its h mos for | ther Star Pole whit glob ina Si dow this lines the] of tl Urs: Bea O: of t] the ] siop' the ¢ stell: form orin tion, the 1 prop mad stars thefi cleat one | cons : Big N tion: and a lin latte that per’s Regt of tl Leo, the ¢ as W Janu the | Lo sky. stars form: towa point is Pega: corne the z latior Up glean tends the | mana this ¢ had stars, talk < stran about

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vw wm iv © ee i I cell oe cee is? ~ =~ ' @ it it f- or r- or of of ye - id pen 4 ae RRR Suhel t. a 3 Aa eR ENERe regeewer ae Saal i i 1 January, 1919 The Stars for January How to find your way in the-skies : By Ernest A. VER on the northeastern horizon is the shape of the Big Dipper, or - Ursa Major—the Big Bear. It * geems to be standing almost upright upon its handle. Follow the line of the two outer- most stars of the bowl and proceed north for about four times the distance between them. A bright star is reached the—Pole Star, or Polaris. On the map the line to Polaris appears curved, because the stars, which seem to the inner surface of a great globe, are slightly distorted in position in a flat projection such as our map. Still facing north, look carefully down toward the horizon, from this pole star. The dim out- lines of a small Dipper appear, the handle bending the bowl _ of the Big Dipper. This is Ursa Minor—the Little Bear. On the opposite side of the pole star from the Big Dipper is Cas- siopeia, the Lady in the Chair. This con- stellation "is in the form of a great W; orinits present posi- . tion, viewed toward the north, it is more properly an M. Itis madeupoffivebright “stars—so bright, and thefiguretheyformso clear, that it is probaly one of the best known constellations after the - Big Dipper and Orion. Note carefully the posi-. tion of the bow] of the small and large dippers. Follow a line from the former to the latter, and continue about twice that distance beyond the Big Dip- per’s bowl. Here is a bright star, Regulus, at the end of the handle of the “Sickle.” The Sickle—or Leo, as it is called—is lying with the crook down and the point up, as welook north and east. In January Regulus is attended by the planet Saturn. Look over into the northwestern sky. Note the great square of four stars, the two sides of the square forming lines which are directed time listed Lelow. Hodgson, of the Dominion Astronomical Observatory Turn now toward the south. There is a sight never equaled in the summer.skies. Half way up the southern sky, immediately before us is the constellation Orion. The STAR MAP FOR JANUARY How to Find Your Way Among the Stars This map represents the appearance of the sky at the It is specifically arranged for the latitude of New-York, 40° N., but is practica_le for ten Cezgrees 01 either side of this latitude. at the times indicated. Hold it over your head with the north horizon to the north. - Use the map ly and its great horns are tossed upwards toward the twins—Castor, and Pollux. For thousands, perhaps millions of years, Orion has kept them safe from their savage foe. In January, Jupiter ‘will add his bright disk to the already bright group of stars above Orion. (See the planet map on page 79.) . The little group, the Pleiades, is known to most people even if they know little else about the stars. The Pleiades, together with Orion and Aldebaran, are mentioned in Job 1x, 9, and Job xxxvi, and the two former in Amos vy, 8, which serves to show how-well known they were to the people of those days. The Pleiades are re- ferfed to as. the “seven stars.” ~ It was considered % a good test of eyesight . _ to be able to count the whole seven stars and be certain of’ them. With a telescope the. group becomes a great .-mass- of- stars, the brighter ones sur- rounded with a great nebulous glow. . Above the Pleiades is Algol, really a ‘pair of stars, one a dark star — or, at least, darker than the other. Once in two days and nearly twen- ty-one hours, the darker star revolves around in front of the bright one. This causes the combination, ordinarily of the second magnitude, to lower to fourth magnitude for about half an hour. It was called by the ancients “the demon of tie slowly winking eye.’’ Mira, in Cetus, is another such variable star. ; Other bright stars in the southern sky are Procyon in Canis Minor and Sirius in Canis Major. This last is the brightest star in the sky, and it is the nearest star visible in these latitudes. In the east, just below the Sickle, is Hydra, the Dragon. Its tail falls far below the horizon, but its head toward the pole star, as were the December 9, midnight January 18,9 P.M. is easily.seen to the east of Procyon. pointers of the Big Dipper. This . 15, 11:30 P.M. ss 25:;-6:30° “ By another month it will have is called the Great Square of “22, 11 8 February 2, 8 e crawled forward in the sky until al- Pegasus, although the star in the "29, 10:30 © s 9, 7:30 7 most all of its shiny length is - corner nearest the pole and nearest January Po Din 33 * = A i visible. the zenith belongs to the constel- lation of Andromeda. Up near the zenith, above the pole, gleams the bright star Capella, and the at- tendant stars of the constellation Auriga, the Charioteer. How did the ancients manage to see the form of a charioteer in this group of stars? The shepherds of old had all night to spend looking at the stars, and they had little else to think or talk about. Is it any wonder that they saw strange shapes and had stranger stories about their visions? All times expressed in Eastern Standard Time. shepherds fancied here a great giant. Betelgeuse is in his raised right arm. Rigel defines his left foot. A triplet of bright stars forms his belt, and, dangling frora it, are a line of three fainter stars, the dagger. The lowest of these appears hazy. It is the great nebula of Orion. Orion is about to deal a blow with his club at the head of Taurus, the Bull. The Bull’s red eye—Adebaran—gleams wicked- 77 Many people do not even know that the stars rise and set as do the sun and moon, and for the same reason. As the earth revolves on its axis, the sun and stars seem to move. . After one becomes familiar with a star group in the southern sky, it is interesting to get two trees or similar marks in line with the group, and after something like half an hour to sight along the marks again to see how far the stars have moved west- ward—or, rather, how much the earth has turned us eastward beneath them.

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Popular Science Monthly Where to Look for the Planets where the planets are for the month of January, 1919. The Sun—the eenter of our system—has seven other planets besides our Earth revolving about him. If we could take a journey from the Sun outward, with a speed of 186,000 miles a second,—the velocity of light,— _ we would reach the first planet, Mercury, in a little over three minutes after leaving the Sun. Continuing our journey outward, -Venus would be reached about six minutes after the start. Then we would reach the Earth at the end of a little more than eight minutes; Mars at. the end of nearly thirteen minutes; Ju- piter. would require over forty-three minutes; Saturn nearly one hour and twenty minutes; Uranus almost two hours and: forty minutes; and finally we would reach the outermost planet, Nep- ~tune, after a journey of about four hours and ten minutes. -. Now, if we chose our: di- rection so that we headed directly for the nearest fixed star when we first started, and if we kept on at our terrific speed, we would have to journey for about four and one third years to reach this star, Alpha Centauri. It hap- pens that this star is too far -south to be seen from these latitudes. If we had chosen the next nearest star it would have been Sirius; but our journey would have been one of 8.7 years before we reached our destination. In other words, if Sirius were to be blotted out today, we would continue to see it for 8.7 years. To put it another way, if we represented the orbits of all the planets on a page of the PoPpULAR SCIENCE MONTHLY, we would need to make that of Neptune about six inches in diameter. On the same scale, to plot in the position of Alpha Centauri, we would put a dot out a distance of only a little less than a mile. So our solar sys- tem is really a very small family circle, after all. All these planets shine only with the light from the-sun. None are self-luminous. They therefore show phases, as does our moon. If we look over the map, we shall find many things with regard tothem. The directions printed with the map on page 79 will explain how it is to be used. The moment or two spent in cutting out slips of paper for the horizons will prove of value. TT planet map is constructed to show An Hour Equals 15 Degrees Mercury, for the month, is near the Sun, which is in the constellations of Sagittarius and Capricornus during the month. If we take a slip of paper and measure on the scale below the map, the . distance separating the Sun getting farther away from the Sun until it getssofar that it finally reaches a maximum. _ This limit, really comes on—January 7, and Mercury is said to be at its ‘“‘greatest elongation west’ on that date. It is then 23° 13’ from the Sun. (An hour is equal to 15°, as will be easily remembered when we note that twenty-four hours takes us a complete circle of the sky, or 360°.) Mercury, being to the west of the Sun, rises and sets before it. It can therefore be seen only in the morning, and it is called a morning star for this month. It is so close to the Sun as to be hard to see; but if looked for in the proper part of the sky, about January 7, it can be seen rising short- ly before the Sun. The sign for Mercury resembles the one for Venus, but the little cup on top reminds one that it is intended for Mercury. This, of course, is only an aid to memory. The sign for Mercury is ‘one that has come down from the ages and has no such meaning. The Evening Star Venus, throughout the month, is to the east of the Sun, and so sets and rises after it. It can therefore be seen in the early evening. It is, this month, an evening’ star. If tested, as was Mercury, it will be found to be continually increasing its distance eastward from the Sun. It is readily seen in the glow of sunset. Mars—with the sign of the war-like arrow, darting forward over the small circle—will be found to be nearing the Sun. It can also be seen in the early evening, setting after Venus. Jupiter, strange to say, is not moving to the east as are the others. It is ap- parently moving westward among the stars. It does not move very far in a month, and, being near Gemini, adds greatly to the beauty of the evening sky. Cut out slips of paper f2r the horizons for use with the map It is almost exactly on the ecliptic, and so serves to show the position of that line in the sky at the present time. On January 1 it is directly opposite the Sun in the sky, and is then nearest the earth for its present circuit. It is then said to be in “opposition” to the Sun. If one is used to judging the ’ daylight hours by the sun, the night hours can be similarly judged by Jupiter around the first of the month. Saturn is very close to Regulus. It, too, moves westward and but a short distance for the month. It makes a striking showing about the first of the month, and when it is a little above Regulus. Neptune is too faint to be seen without a telescope. It is also moving westward, and moves only a_ short distance in January. But, though the _ three planets that happen to lie in the upper map all move westward, and all move but a short distance, it is not be- cause they are all in that half of the map, or because they all move slowly, that they move west. The real rea-. son for their “‘retrograding,” or going backward, is best shown by a diagram, and will be explained. more readily when one of them pauses just before going in its proper direction eastward. Uranus is near Mars and is too faint to be seen with the naked eye. coum fowr ERM. Jand The Moon This Month The moon at the first of the month is just about to enter Sagittarius. The Moon’s positions are for midnight, pre- ceding the date given, in Eastern Standard time. It is west of the Sun on the Ist of the month. On the 2d it is still west of the Sun’s position for the second, but on the 3d it is east of the Sun. It is easy to estimate that it was at the same position —or right ascension, as it is called—as the Sun at about three hours on January 2. It is then said to be in “conjunction” with the Sun. It is, however, above the Sun, and so does not eclipse it. So on January 2 the moon is a dark ball just above the Sun. We then have “‘new Moon.”’ On January 15 it is west of the position of the Earth’s ‘‘shadow.”’ On the 16th it is still west. On the 17th, however, it is east. It is easy to deduce that it is even with the “shadow” at about four hours on the 16th; that is, directly opposite the Sun—i.e., in “opposition,” as was Jupiter on January 1. It is now “full Moon.” Since it is below the Earth’s “shadow,” it is not shaded, and we get no eclipse of the Moon. It is easy to find the date when the Moon is exactly six hours and Mercury on January 1, 5, 10, etc., we shall find that . the distance on the Ist is in- creased by the 5th. On the 10th it is the same, on the 15th it is less, and it is in- creasingly less until the 31st. That is, Mercury, at the first of the month, is continually The POPULAR SCIENCE MONTHLY intends to publish every month an article by Mr. Hodgson like this—an article that will help you to find your way among the stars., If you feel that the articles can be improved in some way that will be more helpful, write to the editor. that you would like to ask about stars (even though the ques- tions have nothing to do with these articles), send them along. And if there are questions from the Sun and to the east of it. We then have ‘first quarter.”” When it is the same distance to the west we have “third quarter.” The former position is reached at about six hours on January 9, and the latter at eleven hours and twenty-two min- utes on January 23. 78 ape ame “tos dis tts. a a Jani F w ter th the a define: the sp yearly which celesti: planet close t The sphere divide in one opposi exact C as the seen if cylind dot in atac “shad same side o' The earth

Page 75

et etna aeasenans aii neal, me ame st i ee oe: ee eee eS Ss January, 1919 How to Use the Planet Map stars above us, an amount indicated by the space be- tween two successive hour lines. The stars appear to travel across our southern sky from left to right as this map is drawn. 2 The lines marked ‘‘Eastern Horizon” and ‘Western Horizon” show how the horizon line will cut the map for the latitude of New York. It is approximately the same for any place in the United States, southern Canada, northern Mexico, and all corresponding lati- tudes throughout the world. It will be convenient for the reader to cut out two slips of paper having the curve of the western horizon on the left edge of one and the curve of the eastern horizon on the right edge of the other. The points where the curve cuts the parallels should be indicated on the paper, for convenience in placing them. The horizon lines’ shown indicate the approximate position at 6 P. M. on the first of the current month. The western horizon is so placed that it cuts the equator immediately above the sun’s position for the date in question. The eastern horizon is immediately opposite in the other half of the map. The west and east points are situated where the horizon cuts the celestial equator. They are, of course, twelve hours apart. ‘The zenith, or point overhead, is, for any given position of the horizon, midway between the east and west points and at the extreme top of the map. -The _south point is 90° below the given zenith which results in its being 10° below the limit of the map. To determine what part of the sky is visible at any , chosen time of any given date, one has only to place the western horizon as follows: for 6 P.M. so that it crosses the equator, immediately above the sun's posi-_ tion, for that date. For one hour earlier (S P;M.) slip the horizon, parallel to itself, one hour to the right; for two hours earlier (4 P.M.) two hours, etc. For one hour later (7 P.M.) slip the horizon parallel to itself one hour fo the left; for two hours later (8 p.m.) two hours, etc. (Note that when one comes to either end of the map, he may proceed to the opposite end of the other and continue as before). Once this western hori-. zon is placed, the eastern is placed in the other half of | the map, immediately opposite. Then all the sky to the left of the western and to the right of the easterh horizons is visible at that time on that date. : One can thus tell whether any planet is visible at any particular time. It can also seen about how far up it is in the sky. Its exact position can then be de- termined from the adjacent stars. ~ 4 Mercury lies so close to the sun as to be scarcely ever seen. Venus, Mars, Jupiter, and Saturn can be seen as bright stars, when properly placed with respect to the sun. Uranus and Neptune are too faint to be seen with ; the naked eye, but are visible in a small telescope. The moon positions are indicated by dots. ter of a celestial sphere of infinite radius upon which the stars are placed, and if we suppose further that the axis of the earth, produced to meet this sphere, defines its poles, then the celestia] equator will lie about the sphere 90° from its poles. The sun in its apparent yearly motion travels along a path called the ecliptic, which is a circle in the sky, tilted with respect to the celestial equator at an angle of about 232°. The planets and our moon travel in apparent paths that lie close to this ecliptic. The planet map shows a belt about the celestial sphere, 40° on each side of the celestial equator. It is divided into two halves, so arranged that any point in one half is opposite in the sky to a point immediately opposite in the other half of the map. If we wish the exact opposite point, it will be as far above the equator as the first point.was below, or vice versa. This is easily seen if we imagine the map cut out and joined into a cylinder and set on end. The earth will now be a mere dot in the exact center of this cylinder. If the sun lies at a certain point in one half of the map, the earth’s “shadow” must lie in the map opposite, at a point the same distance from the equator, but on the opposite side of it. That is, the I’ we suppose the earth to be a mere dot at the cen- The vertical lines are “hour’’ lines. earth in its daily rotation turns us about through the demeglenpaaninnr Ene” ee re: ay hRehancy SS xi x1 Vill VIL VI V IV pis IL TH G.*. h. | avin r ] Tf 6PM JanI 40 7 ge \ OEP lawton we i IMS a ata Ps ORS: Re, CRs vk igh cg Raat GEMINI poe ee Cee ds Le 7 Ege Sod wee, 3 2) By Ses Se »Piéiades | “TRIANGHLA ree is * 2 ae ‘ : ea a a = ran Were a = - be 1+} 20° wet Nis i \F. > walbefarans ft PARIES| PISCES | . se os: a WER AES / oe ‘ 3 ee ta , et # SY. ‘ - ssf oo- oe -~ - TS Ran q “hoe ee CANIS MINQR. \. TAURUS 9-1. o> shi: Se cu ge #Procy . 5 P Py i fe , 4 2= \g ELESTIAL. EQUATOR. , a Sa Jo: i! a / agai. Mira ‘ ; MONOCE i 1. ‘di ; eae sed ¢Rigel ait Fede ee ‘J 10° , ik os s 4 rs + + ‘ H ' Teh bee — i ‘ WA i : A E Rl DANUS Sie : -20° * an Pf “= = os ra J Nees ra Cig. ee al of a Y ARGO NAVIS , Rae "oe i ae x—* Ai ! \ Lv, x FORNAX : / ! “a | a BOS 2 ae - ~ ah a | NM, RS) 40° : % bib uy, ' . Ch i-——_} 4 b L 4 4 — i¢ 3% 2 20 15 10 SOUTH POINT 6PM. Jand °¢) Xxil Xxil XX1 XVI XVx~ xi x1 : q Pie 40° a one joe th ‘ceagees se RONAS d's 30° be % ; ; SER ; ree *. ae Sf Bari ~~ COMA BERENICES ~ bets ‘\ . . +}20° relic ‘ ee} oe SERPENS ' 10° “Soaps ; Pas powerse ee aN | VIRGO . PISCE zB = * WA —ho- oe ED gee H al aes DB Bes 20° Les . Syiae Begs ae ar Sr b> aa aot HYDRA] : a a Ca Be Noted ot 30? q a Eis i i ¢ 8 25 24 23 22 No attempt has been made in ~ this map to differentiate between zero and first-magnitude stars

Page 76

“Made in Nippon’’ is rap- idly replacing the pld Hun boast. Straw hats and lamp-shades for our trade are made in the delight- ful studio shown above Japanese artisans don’t worry much about work- ing clothes; only the boss wears a mustache and a kimono. These men are putting the. finishing Popular Science Monthly : - Japan Rubs Out “Made in Geemany” Mark — This might be a corner “in the garden of my ‘ »., dreams in: Tokio’’; but a glance at the packing-box in the background shows that the dreaming is of a practical sort. The box will go to California packed with delicate dishes and enticing toys, all with the ‘“‘made in Japan” stamp on them TE ee Jar res ins wil fitt bot wit eig the tra are for fee is th thi int touches to vases and jars A Measuring-Wheel to Compute Advertising Space TIME-SAVING invention of The inventor made use of the same | great practical value to the news- principle on which the measuring paper and magazine advertising busi- wheels of surveyors and draftsmen are ness has recently been patented by based, but he adapted the idea to the Alfred K. Washburn, of Providence, specific needs and requirements of the h R. I. It is a machine for measuring advertising business, and introduced a o advertising space in. the columns of number of particularly useful improve- t. newspapers or magazines by inches or ments, calculated to save as much time n agate lines and fractions. Heretofore and labor as possible without diminish- Ss the measuring has been done with a ing the exactness of the measurements. c ruler giving on one edge the inches and The measuring in Mr. Washburn’s n fractions of inches, on the other edge invention is done with a wheel, which I the agate lines. Agate type is used as is rolled over the matter to be “ the standard for measuring advertis- measured. It revolves between the ing matter. > two prongs of a fork with a conveni- € With the old system of measuring, ently shaped handle. It can turn in, t errors were frequent, and the measuring only one direction. ‘ I and adding up consumed. a great deal By a gear the wheel is connected with I of time. After several trials Mr the counting device, which records r Washburn, who is a practical mechanic, each complete revolution of the wheel. I constructed a machine that reduces the An indicator on the wheel itself shows ‘ time required for the measuring to a on a graduated scale the distance . minimum, and not only measures covered, which is not recorded by \the ‘ correctly, but automatically adds up There i se ie is counting device because it is less than f ° ere is no “human equation”’ in ¢ the space measured to a fraction of an diie- Wieke. etseel, which sneansures the circumference of the measuring J inch or agate line: type space quickly and accurately wheel. 89

Page 77

ee OSS, OSS hl CU

TRE AE

January, 1919 HE modern dictating machine dif- ; fers from the old cylinder phono- graph chiefly in the following respects: It is driven by an electric instead of a spring motor so that winding is done away with; it is fitted with a slightly larger cylinder, both as to diameter and length, and with a finer worm feed so that it takes eight minutes to fill up—or listen to— a cylinder, as against four minutes for the phonograph and, of course, the transmitting and reproducing style are finer cut the better to suit them for the finer track which the slower feed gives. The dictating machine is fitted with a device which raises the recorder or the reproducer from the record when the flow of speech is interrupted, or when it is desired to

.convenient where one needs

By E. F. Hallock decreasing the speed of the machine slightly, a full five minutes can be gotten out of each cylinder despite the coarser worm; nor does either the faster speed or the slower cylinder rotation sacrifice aught in the clarity of the reproduction. The next point considered was the means of raising the repro- A Dictaphone Made from an Old Phonograph the arm. The outer end of the arm has 3 holes drilled for the silk cord to pass through, as shown, providing a ready means of adjusting the length of the cord in case the machine is moved to a new location. The solenoid is located so that its axis is in line with the midpoint of the

ducer arm to lift the stylus

from the record and at the same time stop the feed, or forward movement, of the

reproducer carriage. On the

phonograph, this is done by means of a small hand lever, a method obviously too in-

both hands to operate the typewriter. Theusual meth- od on the. come mercial dictating machines is to use a pneumatic con- trol similar to that used to snap theshutter on acamera; but, unless carefully con- structed, such a device is apt to leak air and give rise to endless trouble. It was abandoned, therefore, as im- practical where tools for accurate workmanship were lacking, a simple electrical control being deemed easier

to construct and less likely

to become deranged.

The basis of the electric control device is a solenoid shown in the illustration Fig. 1. It consists simply of a 5-in. length of brass tube, 5¢-in. internal diameter, around which is wound 1 lb.

The solenoid and where it is placed to work the arm attached to the reproducing carriage halt its reproduction for an instant or two in order to put the words into type, and this control is effected by means of a pedal device; a celluloid scale is provided so that the dictator can, with each cylinder, make a notation of repetitions, parts to be left out or changed, etc., for the guidance of the transcriber. The most formidable of these differ- ences to overcome is the length of time which it takes to complete a record. Upon investigation, however, it was found that the earliest dictating machines were equipped for five- minute recording or reproduction, and accordingly a five-minute recorder was purchased and the sapphire style of reproducer was changed for the finer five-minute type. This equip- ment was tried out thoroughly before the mechanism of the phonograph was altered and it was found that by of ordinary double cotton- covered annunciator wire, No. 18 gage, to form a coil about 314 in. in length be- tween two fiber disks driven : Fig. 3.—The layout of the original spring motor as it was used to drive the phonograph record feed worm and also with the outermost hole drilled for the passage of the ‘cord in the extension arm, and the length of the cord is adjusted so that the top of the armature is just flush with the top of the brass tube of the solenoid as shown. The solenoid takes its current from a small transformer which steps down the house lighting current to 9 volts and which is lo- cated in the cabinet of the phonograph. These transformers can be purchased for a nominal sum for operating bells and small electrical toys. A foot push- button is placed in the circuit with sufficient length of flexible cord to bring button to a position for con- venient use by the operator. In Fig. 2 is shown the celluloid scale and the pointer. The latter is a small piece of strip brass riveted to the end of the feed nut spring with the same rivet which holds the feed nut to the spring, it being necessary to replace the original rivet with a new one, of course. The pointer is bent

to a tight fit.on the tube. Its

armature consists of a piece of 3<-in. iron gas pipe 2 in. long, drilled at the top as a means of attaching a small “eye” of copper wire to which a length of silk fishing line is attached.

This simple solenoid is

placed on the floor behind the table or desk on which the dictating machine rests, tions and transmits its motion to an arm attached to the reproducer car- riage at the same point as the feed nut spring, as shown in Fig. 2. This arm is a piece of aluminum, *% in. wide, 14 in. thick and 8 in. long, which is drilled for the passage of the screws used to hold the feed nut spring. The original screws are replaced by longer ones to account for the thickness of ‘ 81 Fig The same motor as shown in Fig. 3 with altera- to adapt it for electric operation to bring the point down close to the scale when the reproducer is brought into action. A couple of pieces of 28- gage brass cut in semi-circular shape are screwed to the base plate of the machine to retain the scale; their straight edges are bent up slightly from the plate to facilitate removal and - replacement of the scale, which is

Page 78

somewhat. slightly longer than the full travel of the feed nut on the worm. The original plan was to discard the spring motor altogether and drive the machine by means of a small‘ electric motor belted directly to the pulley on the cylinder mandrel. The almost certainty of trouble arising from speed fluctuations and consequent distortion of the speech, however, led to that plan being abandoned for one wherein the-spring of the original motor is simply replaced by an electric motor, the friction speed governor of the spring motor being retained intact. The illustration Fig. 3 shows in detail the layout of the spring motor before alteration, and Fig. 4 shows the alterations made to adapt it for electric operation. The entire spring case with the winding shaft, gearing, ratchet and pawl, and also the main drive. gear, were removed and dis- carded. The secondary shaft, which was directly driven by the engagement of its pinion with the main drive gear, was taken out, the pinion removed and discarded and the gear removed. This gear was placed in relatively the same position. on an arbor of the same diameter, which, however, was 2}4 in. longer. On the extension of this shaft was mounted a new spring case, the basis of which is a gear wheel 31% in. in diameter, the largest which can be used without cutting a pocket out of the cabinet. The case itself is a section of brass tube 3 in. in diameter and 34 in. long soldered to the gear wheel and provided with a brass cover soldered in place after the spring is fitted. The spring is of steel, of course, 4% in. wide and 2 ft. long and not too stiff. It is riveted to the case so that its spirals are in an anti- clockwise direction. The inner end of the spring fits into a saw slot cut in the shaft so that the whole casing can be slipped into place after the cover has been soldered down. Both the gear and the casing cover, of course, are a loose fit on the shaft so that they can rotate independently of the shaft; the casing is prevented from slipping off the shaft by means of a brass collar soldered to the shaft on the end, movement in the other direction being prevented by the spring itself coming up against the end of the saw slot. The electric motor was taken from a discarded medical vibrator and operates on 110 volts. The armature shaft as well as the vibratory mechanism was removed and discarded, the shaft being replaced by a longer one of the same diameter. The bearing holes which served for mounting the original spring were reamed to take the electric motor shaft, and the motor was clamped in place between two strips of \%-in. steel near the apex of the triangular cast iron frame of the original motor. Filler blocks of rubber made from sections of an old automo- bile tire were used between the motor and the clamp plates to provide the . unevenness of slight adjustment necessary to bring the shaft into line with the bearings on the base plate and also to help muffle any noise due to the operation of the motor. The motor was arranged to rotate in a clockwise direction and on its shaft a pinion 114 in. in diameter was fitted in a position to engage with the gear on the new spring housing when the motor was clamped in proper position. It will at once be apparent that the motor speed is very slow, a fact which con- duces tosilent operation and absence of vi- bration both of which are essential if good results are to be ob- tained in the reproduction of the spoken words. Any torque due to the slowspeed of the motor and any tendency to jerkiness resulting therefrom are absorbed by the spring drive, the spring being kept constantly wound to its proper operating tension by the motor. While the slow speed of the motor does not make for cool opera- tion, it has not been found in months of actual usage, that the heat approaches the dangerous point. The electrical conneetions, of course, are simple. The motor is directly con- nected to the house mains by means of a special connection plug while the primary of the solenoid is connected in multiple with the motor, so that the operation of a snap switch located on the side of the cabinet turns the current on or off for both circuits. It is important, in fitting the feed nut extension arm, to replace the feed nut spring so that the threads of the nut engage properly with those of the feed worm; make sure that the tension of the spring is sufficient to insure the regular travel of the worm under the slightly additional weight. It may be found necessary, in some cases, to increase the tension by bending the spring down toward the worm slightly, and where such is the case it probably will be necessary to counterweight the weight of the solenoid armature and the extension arm by placing a lead washer of pfoper weight around the orifice on the reproducer. Cleaning Grease-Filled Surfaces on Emery-Wheels HEN an emery-wheel becomes coated with grease it fails to give satisfactory results. Emery that is to be eleaned should be washed with dilute acid after boiling it with a solu- tion of caustic soda. Carbon bisul- phide should be used. 82 and important also to | Popular Science Monthly Holding One End of a Mower Cutter while Grinding O relieve the weight on the arm while grinding a mower cutter, fasten a rope to the head end of the — bar and pass the rope ROSNY over a pulley sus- pended above. Bring eh the rope down to the \ hand holding the knife-bar. This will hold the end up easily. As you change from one knife to another in 4 grinding, the \ rope in the : hand can be \, let out or taken up as required for — ~ = Sy ; ete The end of the hor isheld up on a level th 1 p It the with the grindstone @M8/€. — t le tool-grinder is portable, the pulley is not a necessity, since the rope can be passed over a tree limb or any horizontal stick which is over- head.—GLENN A. GRANGER. A New Sign-Post Made of Metal Tubes HE old-fashioned sign-board with the pointing hand is still used or- dinarily for directing the wayfarer to points of interest; but, at best, it af- fords a poor line of sight, and soon succumbs to the elements. The accompanying illustration shows a simple and durable sign-post. The sighting is done through a piece of 2-in. pipe about 20 in. long, which is sup- ported on top of a piece of the same size pipe set firmly in the ground and standing up about 4 ft. A piece. of ly-in. sheet iron is bent double, fitted over thesight- The set tube pointed toward a mountain shows the traveler what he is viewing ing pipe, and riveted at each end. Connection with the vertical pipe is made by running a 5/16-in. bolt through from one side to the other. A second bolt is then placed lower down, and operates in a circular slot so as to permit the line of sight to be adjusted to the proper vertical angle, after which the nuts are ad- justed tightly. The name of the city should be painted on each side. ae

Page 79

SS tt mV corns: January, 1919 A Comfortable Chair Made From a Twelve-Inch Board EVERAL chairs designed by a local artist for his studio are quite remarkable in appearance, besides be- ing comfortable seats. They were made almost entirely from a 12-in. board. There are only four parts to each chair: One 12-in. board 89 in. long, which is both back and A Draining Rack and Press for Making Cheese HEN the Dairy Division of the United States Department of Agriculture is conducting a nation- wide campaign to introduce methods of manu- facturing and use of cottage cheese on every farm, a cheese-mak- ing equipinent as here de- scribed is simple and front ‘‘legs.” can be made Z ‘ — S== One piece 14 in. long, which makes the seat; and two triangular pieces of the same material and length serving the double purpose of rear legs and sup- ports for the seat. The main piece is inclined at an angle of about 40 deg. to the floor and the braces are so cut that their great- est, upper, angle of 130 deg. is divided by the main piece. In other words, both the seat and the rear edge of the braces are at an angle of 65 deg. to the main piece. , The brace-pieces are mortised into the main piece and fastened with screws, and the seat is also screwed to the braces and to the back. It is probable that a simpler chair deserving the name could not be made. On the other hand it is really astonish- ing how much comfort is to be had from these narrow and angular pieces of furniture. ~This is due to the angle of inclination of the back, which per- mits a position of the body possible only in a rocker or a Morris chair—or by tilting back an ordinary chair. make the seat and These chairs are cheap, quickly - made, strong and durable and could be used to advantage in a good many places where uncomfortable seats would cost just as much or more. ‘A Home-Made Prick Point for the Draftsman “THE instrument shown was made from a rubber pen-holder with a wood plug cut and tapered to put ——— a 1. js Closed PSS 4" Of hard rubber penholder Needle An old rubber penholder makes the handle for a prick point fitted in a plug in the hole. One end of the wood plug is fitted with a needle. When not in use the plug is reversed and stuck into the tapered hole of the pen- holder.— THOMAS O. WANSLEBEN. Studio chairs made from a single board cut to at home. It can serve profitably in the capacity of converting surplus milk into a valuable food in the family diet. There are ap- shape the rear legs proximately 10,755,790 farm families in ° the United States and the production of two pounds of cottage cheese.a week would aggregate 1,118,603,160 pounds yearly. The rack for draining the cheese is 16 in. deep, 12 in. wide, and 24 in. long, and is cut from pine timber. The bottom slats which hold the pan under the draining cloth fit into notches made in the lower side strips and can easily be removed when the rack is washed. The corner posts extend 34 in. above the strips at the top and the corner A small wood frame to support the cloth for draining curdle to make cottage cheese loops of the muslin or cheesecloth used as a drain cloth are looped over the posts. A rack can be made out of an orange or vegetable crate as shown in the accompanying illustration. The press consists of two poplar or maple boards 114 in. thick and 144% in. square. Strips of wood 1% in. wide are nailed or screwed on the back of each board to prevent them from warping. The boards are planed and sand-papered until altogether smooth. The lower board has a circular groove which has an outlet through which the whey drains as it is pressed out of the curd. A wooden paddle, a dairy thermom- eter, and a food chopper or sausage grinder complete the cheese-making outfit for farm use. The molding tube or cylinder can be made by a tinsmith or purchased from a hardware store. 83 The paddle can be made easily at home. The molding tube is designed to mold the cheese into attractive and Nam ays i. \ ‘ole / / ~ a ~~ = NIG | | | Al r | i | Li ia CGROOVED FOR DRAIN Dimensions of the parts for making the stand and the parts for the press convenient form for the market. The cheese can also be packed into small glassjars by placing the opening of thejar over the end of the tube through which the cheese is forced.—S. R. WINTERS. A Solution for Removing Grease from Machinery Parts HE following method has been sub- stituted for the use of gasoline and other light oils: Boil the parts in caustic soda lye,—1 lb. to a gallon of water,—then brush while the articles are hot. Caustic soda is recommended as better than ordinary soda, since it causes the fat or grease to dissolve more quickly. How to Raise a Stuck Window in a Railway Coach HE windows of the average rail- way car very frequently stick or jam when closed, and cannot be opened . no matter how strong a lift is applied to the lifting lug. When once raised even a little, the window invariably rises the rest of the way without any trouble. The sketch shows the shank of the foot-rest of the seat usually found under the seat ahead in a position for a handy lever to loosen the window. By getting the end of the slide under the finger lug and resting the remaining por- tion on the sill, a leverage is readily exerted which willloosen any obstinate window. The foot-rest and slide slip very easily out of their slot under the chair. This discovery may be of interest tosome suffocating traveler sitting near a closed window.—F. W. BENTLEY, CATCH The foct-rest end placed under cat-h

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An Electroscope SENSITIVE electroscope is al- A ways a most useful if not an indispensable instrument in the equipment of every laboratory. Use has generally been made of the electroscope in detecting and de- termining the nature of minute elec- trical charges. The same principal, however, has been applied to a method of measuring delicate potentials and, quite recently, to the detection of feeble radio-active bodies. Since the former application may more properly be termed an electrometer and the latter involves an apparatus beyond our immediate needs, a very sensitive type of the common gold-leaf electro- scope will be the subject of this article. The flask of the electroscope has a capacity of about twenty-one cubic inches and a mouth of about 1% in. in diameter. Such a flask can be purchased for a small sum from some chemical supply house. Its height should be about’ 634 in. from its base and be about 334 in. in diameter at its largest point. Two 34-in. brass balls should be procured at the same time. When these- have been obtained proceed as follows: Drill a %-in. hole to a depth of 3/16 in. in one of the brass balls and saw the other in half. One of the hemispheres may be dis- carded but the other must have a \%-in. hole drilled through its center perpendicular to its plane face. Tap both of these holes with a 10/32 machine thread. taken to protect the balls during the drilling and tapping so that their sur- faces will not be marred. A piece of 3/16-in. brass rod must be cut so that there are two lengths; one 244 in. long and one 314 in. long. The shorter of these two rods must have both its ends threaded to a distance of 3/16 in. with a male thread corresponding to that in the ball and hemisphere. Thread one end of the longer rod simi- larly, but with the aid of a hack-saw cut its opposite extremity lengthwise to a distance of 44 in. Cut a rectangu- lar piece of 1/16-in. brass, 4 by 34 in., and insert the same longitudinally in the slit prepared in the brass rod and solder fast. After the superfluous solder has been removed with a file, the rectangular plate may be trimmed as._shown at A. “Screw the ball, B, to one end of the short rod, C, and the hemisphere, D, plane face out, to its other extremity. After the long rod, E, has been screwed to the plane face of the hemi- sphere, polish the brass with pumice- stone and lacquer everything except the ball, B, and the plate, A. Obtain a cork somewhat larger than the mouth of the flask and with the help of a sharp razor blade trim it so Care should be Popular Science Monthly for Detecting Small Electric Discharges as to make a nice fit, care being taken not to-have the fit too tight for fear of breaking the thin walled flask. Place the cork on the floor and roll under the foot until it has become a The flask and its mountings for holding the gold foil, which is the most delicate part great deal softer. Sandpaper its sides smooth and bore a %%-in. hole through its center with a cork-borer. Cut the cork to a length of lin. A piece of glass tubing, F, with a 14-in. bore and a 1/16-in. wall must be cut so that it is 154 in. long. This is then inserted in the hole prepared for it in the cork, G, in such a manner that one end projects 14 in. above the top The flask is mounted on a piece of glass set on porcelain knobs of the cork and the other end falls 14 in. lower than its bottom. Place the long rod, E, through the glass tube, F, so that the plane face of the ‘hemisphere, D, shall rest upon that end of the tube projecting %% in. St above the cork Invert the whole and fill. the glass tube with molten sealing- wax, H. When the insulation has cooled the rod will be embedded in its center. Some gold-foil, which can be pur- chased for a small sum from a glazier, must be cut into strips 14 in. wide and 244 in. long. Try to have this cutting done by a professional, but if this is impossible it is best done by leaving it between the sheets of paper as it comes and cutting paper, foil, and all. The plate, A, should be smeared with albumen, thin shellac, or, better still, a solution made by dissolving a large capsule in a teaspoon of warm ether, as an adhesive. Two strips of the gold-foil, J, are then affixed to opposite sides of the plate, leaving 2 in. of the strips hanging free. Fixing and attaching the gold-leaves is the most difficult operation in the whole process and much patience will be re- quired before two leaves can be proper- ly fastened. The foil, of course, can- not be touched by the hand and must be handled exclusively by some im- provised instrument such as a narrow strip of paper. Few hints can be given as to the best way to proceed with the attachment, so the constructor must rely upon his own resources and go about the task as an ardent supporter of the ancient maxim that “experience is the best teacher.” The flask, J, must be clean and dry. Before placing the cork contain- ing the rod into place ‘permanently, heat the flask for a few minutes at a moderate temperature so as to drive all the moisture from the interior. While the flask is yet warm, place tie cork in the top so that it is \& in below the mouth. Pour molten seal- ing-wax, K, on the cork until it is level with the top. Give the neck of the flask several coats of shellac on the outside to prevent moisture approach- ing the insulation. If it is desirabie to make a con- densing equipment for the electroscope, cut two disks, each 21% in. in diameter, from 1/16-in. brass. By means of solder, L, affix a piece of %%-in. brass rod 5/16 in. long, M, to the cen- ter of one of the disks, N. Drill a \-in. hole, O, in the end of the rod to a depth of 3/16 in. and tap as was the case with the charging knob. This constitutes the condensing plate which, when in use, displaces the charging ball. The other disk, P, which forms the collecting plate is fastened by means of wax, Q, to the end of a rod, R, of some insulating material such as hard rubber, glass; or fiber, 31% in. long. Polish both plates and lacquer. The lacquer must not be dispensed with for it is necessary as the dielectric of the condenser.—MARK M. GEATRY.

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January, 1919 . x CLAD SUCUUPELECULECEVEV EC EOL SEEDED ERE ERO LU LEEE OE LE PELL ERU ET EL OT ELE PSD PEPE TEE TEU TEU PTET ET PRTELEP PEPE EP PEELE LELES PEELS EEUU E yok 1760 Packard Trucks Complete National Truck Efficiency Test Winning Truck Ectatiliities 3 Months’ Record of 952 Points out of 1000—$5025 Awarded in Prizes EUCUUUDEN EEL UUPUCYULEURRE DCP EET CULES ATU ET ES EUEEV ED ESOT O CEE LULU TET ELUU DUST DUA UE TT LEV UUEOD TY EVT EE FOUCC TUCO TELL OEY N UTEP EEE ES LOU EU EEE PEEL EEE CUE SEPT UPPED ULEE EEE C ES EERE TET Y When National Truck Efficiency Test was organized being recorded daily on the National Standard Truck and conducted by the Packard Motor Car Com- Cost System, as perfected by the Truck Owners’ pany in co-operation with the efforts of the National Conference. Council of Defense and the War Industries Board The trucks were divided in three classes, accord- to put motor trucking on a basis of higher efficiency, ing to capacity. and to save railroad facilities for urgent Govern- Prizes were awarded in each class— $1000 to the ment uses. owner of the winning truck; and to the drivers, The test consisted of three months’ running, all $500 for first, $100 for second, and $75 for third best phases of the truck performance and truck costs ‘ records, The Prize Winners in the National Truck Efficiency Test Class A—1%% and 2 ton trucks Class B—3 and 4 ton trucks Class C—5 and 6 ton trucks FIRST: What Cheer Chemical Co.,Paw- FIRST: H. F. Cherigo & Sons, Baltimore, FIRST: W. M. Hoyt Co., Chicago, IIl., tucket, R. 1., James L. Drury, Driver. Md., Lew Bacighipi, Driver. Joseph Brookbank, Driver. SECOND: Edson Moore & Co., Detroit, | SECOND: Salt Lake City Pressed Brick - SECOND: Gottfried Krueger Brewing gg Foose 2 gg! laa Co.,SaltLakeCity, OloffHanson,Driver. C0 Newark, N. J., Charles Langbein and Joseph Birchler, Drivers. THIRD: Edson Moore & Co., Detroit, a cogs Harper & Wilz, Baltimore, Md., THIRD: H.F. Cherigo & Sons, Baltimore, Mich., L. Moore, Driver. C. Wilz, Driver. Md., J. Butts, Driver. : ¥} y HIS three months’ test of 1760 States but can benefit by the results of the Packard Trucks in all parts of | Packard National Truck Efficiency Test. . PLUIASANAHAAGARLLAALARDAGAIALLELAIIAALAOLATLAAAAIATALILATAAAAALLALLIAAAAEALE TULLE TTD TALE ETAT LT Cote 2) the United States is the first They are transportation results. all-’round and nation-wide test They are just as applicable to the single of truck hauling ever conducted. truck as to the fleet—to the little delivery It is the first to consider and record car as to the Packard. the transportation factors that enter into Whether you are a Packard Truck user truck. efficiency:— or not—the Transportation Department cia eee of your local Packard Branch or Packard | Type of Country Percentage of Capacity Dealer will be glad to see you. They will State of Roads Economy in Gasoline talk the thing over with you—show you Type of Tires Economy in Tires h - 1 look: & ct gl Seareinndl an what transportation results to look for Loading and Unloading —_ Economy in Upkeep and how to record them day by day on Time Wage Cost the National Standard Truck Cost System." One of the most vital things for the Many a truck owner, discovering that Nation today is that every transportation his fleet is costing more than it should, agency shall come as near 100% efficiency finds all his efforts at economy baffled— as possible. Outgoing Load Condition of Truck because he thinks of efficiency only as a It is an extension of the Packard matter of trucks. program of 100% War Work to give the Truck efficiency depends on transporta- results of this test to every truck owner tion principles. or driver who will make use of it—/freely, There is not a truck owner in the United and without thought of imposing onan PACKARD MOTOR CAR COMPANY Detroit, Michigan PITTTTTL TEPC TCU CeCe eee COD eo AC TOMSEAUAEERALOED QUCUUDSEDOGASEDEOALAAOOAASTVOCOCOCOSOPREEOUASOOSOOUPEOEESCOUCUCSPUOEROACUTOOPEROOCCUCOD CE EEEEOREOOQOU UOC CRCEPECUO TEEPE EOSPEPOOTCEECOPROOTOOUTOPEECOSTAOOPOEPEPOUUPE PEO ELERCOREPASTORSUOPOPE EA CLS RULRERREED EEE E HINA EEE 85

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You’ve got to have the right pencil Tf your pencil work is to be always up to top speed, top efficiency, you've got to have a pencil not only: of the best quality but of the degree of lead ex- actly suited to your work. DIXON'S oRADO the master drawing pencil” is proclaimed by artists, - architects, engineers, business men and other connoisseurs, as a real American achievement. The strong, long-wear- ing leads do not easily break or wear down quickly. Their respon- siveness makes your work less tiring and quicker. First of all specify the - Eldorado; then be sure you are getting the right grade. How to find your grade. Note in the chart below that 6B is the softest, 9H the hardest and HB is medium (the degree most used in general work), Select the degree you think will suit your work and your liking. If not exactly right, next time choose a grade harder or softer. When you have thus found your degree, specify it every time and you will always have pencil satisfaction. SRE SOEs Sr the degrees you want and we will send you full-length samples worth double the money. _ JOSEPH DIXON CRUCIBLE CO. , DEPT. 120-J JERSEY CITY, N. J. Established ce ae A R. MacDougall & Co., Lid., Toronte, Ont. a : s) 4 a : : S| © = = © 5] & 4 = ry S. ® K ~) g 8. 6B Varyin ‘degrees of H Hard. SB >extra Softness—6B 2H Harder. 4B ) softest: 3B Extra soft and black. 2B Very soft and black. Varying B Soft and black. degrees of HB Medium soft. a = | F Firm. 9H hardness. 3H Very hard. 4H Extra hard. A Removable Bag Receptacle for a Park Rubbish-Container DURABLE and inexpensive de- pository for scraps of paper and rubbish that accumulate around re- The cloth bag is held open by a metal ring and it can be easily removed for dumping sorts and picnic grounds may be made 1 in the following manner: An iron ring large enough to stretch a gunny-sack over is provided with six projecting hooks riveted firmly in place. This ring is then riveted to the top of a 2-in. pipe, the connection being strengthened by the addition of a piece of -in. steel plate curved to the same radius as the ring, and riveted to both the ring and the vertical pipe, which is then set firmly in the ground, prefer- ably in a cement base. After .painting and lettering the plate, drop a gunny-sack through the ring and stretch the upper edge over the hooks. Such a receptacle may be easily emptied, and it is a very simple matter to replace the sack when it is worn.—JOHN D. ADAMS. Sights for More Accurate Shooting with a Shot-Gun T has always been understood among small-game hunters that a crack rifle shot could not hit anything with a shot-gun, in spite of the fact that his aim with this firearm does not have to be very accurate. Here is the way I fitted out my shot-gun so that the RED WHITE AS SIGHTS APPEAR TO SHOOTER REAR SIGHT The ring with a white ball center makes it easy for the hunter to sight his gun FRONT SIGHT aim is just as precise and definite as that of any rifle. A ring was mounted on the screw for the front sight, the ring being 114 in. in diameter (inside measurement). The rim appears to the one sighting R6 Popular Science Monthly the gun to be about lin. thick. The ring was painted a bright red, as red shows up best against any kind of a target and stands out very distinctly when aiming at moving game. A small hole was drilled and threads cut to receive the ring-screw 2 in. from the muzzle end of the barrel. The rear sight is a vertical post 1% in in diameter, topped with a ball 14 in. in diameter, all projecting 34 in. above the barrel. This is painted a dull white color. The post screws in place 24 in. back: of the front sight. With this combination of white rear post and red ring I find that I can easily bag my share of game. It is also a very clever sight for the “rifle crank”? to use when he shoots the scatter-gun at traps. The principle involved in this kind of sight is this: when the white ball aligns anywhere within the ring with your target you get your game.—F. E. BRIMMER. Centering Round Stock with a Vise and Scriber VERY simple method of finding the center on a round piece of iron or a bar is to clamp a center punch or scriber in the jaws of a vise, so that its point extends above the jaws to about the radius of the bar to be The bar is placed on the marked. To get the center of a round bar, roll it be- tween the jaws of a vise holding a scriber jaws and revolved by hand against the scriber point. If the point is not exactly in the center, a circle will be marked so that its center will be easily found. The fact that the jaws are slightly open on account of the scriber being clamped in them provides a trough, or ways, in which the bar may be easily rolled.—JOHN SCHMELZEIS. How to Make a Nickel Alloy that Is Malleable AGNESIUM added to nickel or cobalt, when put into the fused metals in the proportion of one eighth of one per cent, will render these metals malleable. The nickel will also become ductile when mixed with this small proportion of magnesium, while the cobalt loses its color and becomes whiter than the nickel. Both of these metals can be made to adhere firmly to iron or steel at a white heat. orca RARNOE RR ETM ann Ja re as De nm TD

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January, 1919 A Novel Rope-Holding Device for the Ground LIGHT form of a deadman that is very convenient for a pull di- rectly upward is shown in the accom- panying illustration. It consists of Rope inch pipe stake 2 inch pipe Ground 4% »- aaa 2 ved Level Pig hs Mihir c oe. “a Pree «ote \ \ / / NA ‘ " 4; ‘ & \\ o ‘ \\ Le Vy Na ‘A With the cross stakes at each end and the two parallel bars as shown the whole cannot be drawn from the ground stakes or short pieces of pipe driven in the ground at an angle, with cross- pieces above and below where the stakes cross. The rope is secured about the two cross-pieces. This form of a deadman is quickly set, and will stand any pull that will not break the stakes or bend the pipes. —WALTER L. MORRISON. Removing Dampness and Disin- fecting a Cellar ELLARS will acquire a musty odor after. being closed up for the winter. To remove dampness as well as to disinfect the cellar, sprinkle chloride of lime on the floor and close up the cellar for a few days. Then open the windows and let in the air until the chloride-of-lime odor disap- pears, and your cellar will be ready for storing vegetables. How to Make a Valve for a Small Steam-Engine SMALL valve for use on a toy steam-engine or an engine for chemical purposes can be easily made in the following manner. Secure a block of brass 54 in. square and 34 in. long, and drill a hole throughits center. This hole will be governed by the size of the pipe. The hole should be threaded at each end to re- ceive the pipe ends. Drill another hole on the surface at right angles to the first hole, as shown at A. Make the diameter of this hole 1 in. larger than the first hole. Pass a valve consisting of a thumb-screw threaded to fit the threads cut in the last drilled hole through the hole for opening and closing the line.—THEO- DORE P. GATHMANN. THREADED TO SUIT PIPE Small steam-valve made from a piece of brass Multiply: in Man's 1, *‘YANKEE”’ Vise, set on sur- face plate and holding stecl cylin- der for accurate center marking. 2. The centers on the cylinder as above marked, being punched for drilling. 3. ‘*YANKEB’’ Vise (with work) removed from bench to drill press: Holes are drilled abso- ately true. 4. ‘*YANKEE’’ Vise, still hold- ing the work in original align- pote Bal fastened to bed of milling Removable from Base for Continuous Work OU do not remove the work from the “YANKEE” Vise, but move the vise itself—for the various operations, on n bench, drill-press, milling machine, planer, etc. So, you see, the “YANKEE” Vise is needed in every shop—no matter how many other vises a shop has; wanted by every machin- ist, tool maker, motor mechanic, or good. metal worker in any line—because it works in ways and places impossible for other vises: Multiplying Man’s Power! The “YANKEE”’ Vise is machined square, for use on end or either side as well as upright; and is provided with a V-grooved steel block (as illustrated) for holding round and irregular shapes. As a time- and labor-saver, this vise is in a class with “YANKEE” Ratchet Breast and Hand Drills and “YANKEE’’ Automatic- feed: Bench and Chain Drills. “YANKEE”’ Vise No. 1993 with Swivel Base. Price, $7.75 Body 714 by 234 (wide) by 3”. Hardened steel faced jaws; open 33%”. Vise held to base by set-screw. Camthrow lever locks position. No. 993. “YANKEE” Vise without base. Price, $5.25. Your dealer can supply you Write us for free ‘YANKEE’ Tool Book” of drilling, tapping, boring, and screw-driving tools. North Bros. Mfg. Co., NGKOORSS Faker Botton(lochamen, 87 ccna Be Prerene shri POE IET ob ey Se ee ee ee

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Popular Science Monthly Our Nation’s Flags and Their Meaning TRICTLY speaking, the word “flag’ is not used to any great extent in the army. The national flag belonging to each regiment is known as the “national colors,’ and the regimental flag is the ‘‘regimental standard.” The company, troop, and battery flags of the engineers, cavalry, NATIONAL COLO CAVALRY FIELD ARTILLERY SIGNAL CORPS NATIONAL COLORS - . INFANTRY COAST ARTULERY ENGINEERS Chaplain’s flag and regimental flags, the latter being the national colors and artillery are known as “‘guidons”’; ' and so on down the line. A knowledge of the meaning of every flag in use in the army will be found useful not only to the soldier but to the civilian who is, or should be, interested in things military. The accompanying illustrations will be of great assistance in distinguishing vari- ous bodies of troops, which will be met more frequently as time goes on, as well as in distinguishing regimental, brigade, and division headquarters. Most army posts are entitled to hi 1ST BATTALION Company, battery, and troop flags of the first and second battalion, known asguidons 2 BATTALION three flags—garrison, post, and storm. These are what is known as national flags,.and are made of bunting in the sizes indicated. The ‘garrison flag” * eagle, alert, 53 in. high. is furnished only to posts designated from time to time by the War Depart- ment, and is hoisted only on holidays and important occasions. The post =e Se WHITE MAROON * ORANGE” YELLOW BLACK How the colors of the various flags in the illustrations are designated flag is furnished to all army posts, and is always run up in pleasant weather. The storm flag is furnished for all occupied posts, for use in stormy and windy weather. The last named flag is also hoisted -in all kinds of weather over semi-permanent camps and national cemeteries. The colors of the President are of blue silk, and are attached to a single jointed staff 10 ft. 3 in. long, including the ferrule and gold-plated head. The head consists of a globe 2 in. in diameter surmounted by an American + N. 0. k—— 6-8" ASST. SEC. OF WAR The colors and sizes of the flags of the Presi- dent, the Secretary of War, and his assistant In each of the four corners is a five-pointed star, white, with one point upward, the points of each star to lie within the circumference of an imaginary circle of .468 ft. diameter; the centers of the circle being .77 ft. from both the long and short sides of the colors. The coat-of-arms is placed in the center of the flag, the letters and stars being embroidered in white silk on both sides. The colors are trimmed on three sides with a knotted fringe of silver and gold 3 in. wide. The cord is 81% ft. long with two tassels, and is composed of red, white, and bluesilk strands. __ The flag of the Secretary of War is of scarlet bunting having a five-pointed star in each of the four corners, each 88 star having one point upward. The points of the star lie within an imagin- ary circle of 5-in. radius. The cen- ters of the stars are 17 in. from the short side and 12 in. from the long side of the flag. The center of the flag bears the official coat-of-arms of the United States. The chaplain’s flag is of blue bunting having in the center a white Latin cross 18 in. high and of suitable width. 48 STARS 4 een” ' SSS POST- FOR PLEASANT WEATHER Army posts. have three flags—garrison, post, and storm. The garrison flag is only given to certain posts by the War Department These flags are used for field service. Hospital flags are of three sizes, and are used in connection with the na- tional flag in time of war. The guidons are used to mark the way to field hospitals. National colors are of silk, 51% ft. fly and 4 ft. 4 in. on the staff, which is 9 ft. long, including the spearhead and ferrule. The union is 21% ft. long, and the stars are embroidered in white silk on both sides. The edges trimmed with knotted fringe of yell: WIG -WAG WH 38° BATTALION The third battalion flags, together with the semaphore and wigwag flags silk 214 in. wide. A cord 8% ft. long is provided, and this cord is made of red, white, and blue silk strands. Na- tional colors are practically identical

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January, 1919 Make This Y our Home Building Year SEMEL BEDE: That charming bungalow Home—bordered in flowers—bathed in sun-light—the one you have dreamed of can now be yours. bungalow of charming proportions. building library of 100 designs—1oo ideal homes. remarkable book, that will be sent at your request. yi labor in building your home. Aladdin Book shows you how it is done. Aladdin System Saves Waste _ Thousands of our customers have told us of big savings they made building Aladdin Homes. The average saving on our $945 bungalow is $264. The Aladdin system saves waste of lumber. All of the material is shipped to you cut to fit. Your carpenter can erect your Aladdin Home quicker because all of the hand sawing is done in our. mills by Rapid Power Machines. What You Get With Your Aladdin Home. all materials cut-to-fit as follows: Lumber, millwork, flooring, outside and inside finish, doors, windows, shingles, lath and | The material is shipped to you in a sealed box car, complete, ready to erect. Safe arrival of the complete material in perfect condition is guaranteed. Send stamps today for a copy of “Aladdin Homes” plaster, hardware, locks, nails, paint, varnishes. No. 650. This saving of lumber and labor will mean from $200 to $400 or more. Send for this book today. It may be a snug and cosy cottage complete with five rooms on one floor, or a more pretentious These types and many others are found in the Aladdin book—complete home- Besides this there is a vital message for you in this most Saves Lumber and Labor and You'll Save Money Building Your Home course, you would like to save money building your new home—would like to build at the lowest price possible. But, you cannot expect to save very much money by bargaining or getting different prices. to save money by saving labor in building your home and eliminating waste of lumber. Cut Houses are cut-to-fit in Aladdin mills by rapid power machines. 18% to less than 2%—a saving of practically $18 on every $100 worth of lumber. You can only expect Aladdin Readi- Old fashioned building waste is reduced from And you save a third of the The Aladdin’s Dollar-a-Knot Guarantee Aladdin Readi-Cut houses are the finest produced. The choicest stock available is used for the exposed weather parts. Finer materials cannot be had than those used in the construction of Aladdin Readi- Cut Homes. The Aladdin Dollar-a-Knot Guarantee is but one evidence of the built-in quality which is a part of every Aladdin Readi-Cut Home. . Aladdin houses are cut-to-fit—no waste of lumber or labor. The Aladdin price includes THE ALADDIN COMPANY, 651 Aladdin Ave., Bay City, Mich. Canadian Address: Canadian Aladdin Co., Ltd., Toronto, Ontario.

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Popular Science Monthly same in color as other national colors. The regimental standards are of the same dimensions as the national colors, but vary as follows: . The Only Variable Spacer— The Only Automatic Type. 4:0. s Color Strok SCUIDON ae oO nscri troke— Field Fringe Scroll tion e mK - Engineers scarlet white white whit The Only Machine With In- FIELD HOSPITAL Mounted Engineers scarlet white white white h ble T 0" os" a aaoery at — yellow red nfantry ue yellow red shit terc angea ype— Cavalry | yellow yellow red ~aiew i 3 pas ey scarlet = yellow scarlet : ignal Corps orange white All Commercial Type Sets— es , : : The inscriptions on the regimental All Language © standards are as follows: s Ta) U. S. Engineers . Battalion, U. S. Mounted Engineers : U. S. Coast Artillery Corps ; U. S. Infantry 4q n U.S. Cavalry U.S. Field Artillery M h e f ME HOSPITAL ee Signal Corps, U.S A. : ac ine @ The size and colors used for the general re aoe used to identify troops, field hospital and -ambulance flacs batteries, etc., from one another, and also to help guide troops on the march. When you recollect an_ || for engineers, infantry, and coast artil- The, guidons for the various arms of important letter which lery branches, the designation of the % Vice are shown gsi a. eae: regiment or battalion to which the ese guidons are you neglected writing +| colors belong being engraved on a made of bunting at the office, take care silver band placed around the staff. for field service, : : d of silk of it at home on your || ¥ #¢!¢ artillery, cavalry and signal Sables. ae, and reviews. AMMUNITION TRAINS, . DISTRIBUTING POINTS The infantry AND DEPOTS Multiplex Hammond Wee “Writing Machine” ee T Your own personal Multi- plex Hammond is a price- ya less convenience, a worry reven i = : se ; pre ter, a time aisty aad INFANTRY CAVALRY ARTILLERY Ammunition trains, money maker—use 1t at DIVISION HDQTS. DIVISION HDQTS. BRIGADE HDOTS. telegraph stations, home. CAVALRY-YELLOW FIELD i apg and motor- Field army headquarters, infantry, — Foie ye “ - 4 A New Portable cavalry and battery brigade flags & Condensed ; POST OFFICE corps the national colors are mounted . - Aluminum on a lance 91% ft. long. The union does not use guidons, but has ‘“‘com- is 22 in. long, the stars being em- Pany flags.”—-GEORGE M. PETERSEN Only l1P ounds broidered, and the fringe being the aaa Full Capacity : oo To Prevent Unconscious Retard- ing of the Automobile Spark | AS any Ford driver, who was too tall to fit his car, ever noticed that, when driving at 20 miles an hour AERO SQUADRON(SIGNAL CoRPS OF more with the spark well down, his knee is always pushing the lever up again, and so he is continuously though unconsciously retarding the spark? === This difficulty may be overcome by 2 a = bending the lever-3 in. more than the — 7 original bend. It is astonishing what TEMGiGNAL CORPS) a difference will be found in the avail- able space. To bend the lever, however, is more easily said than done; it is necessary to use two large adjustable wrenches. One should be slipped over the short bend of the lever to hold it in position, and the other should be used to do the bending. The second wrench should be placed at the extreme end of the lever, and in some cases it may be necessary to slip a piece of gas-pipe over the handle to abtain sufficient : an leverage. Get someone to hold the ganda Sp x Soman first wrench for you while you do the other and so aids marching troops bending.—J. S. CHAPMAN. TYPE SPECIMENS: Vertical soribt - private tetters. Medium Roman-general letters. Italic - emphasizing. Special GoTHIC — CLEAN CUT Large Gothic - sermons, lectures. Large Roman - sermons, lectures. Print-type - new, attractive. No Other Machine Will Do This FREE Illustrated Booklet Let us send you, free, our in- teresting booklet describing the unique features of this extraor- dinary machine. The Hammond Typewriter Co. = 639 East 69th St New York City — ORR CONEY ‘Write for special terms to professionals 90

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January, 1919 merely) HCH PRATT Precision Model Lathe No. 700 COMPLETE lathe designed for the accurate plished. This lathe is particularly adapted to small tooling of small work. precision work such as is usually done in the laboratory. This lathe has a 12-inch bed and an extreme distance Doctors, dentists, jewelers and inventors will find it of 334 inches between centers. It swings 5 inches. This ©*°¢edingly useful in their laboratories. lathe is provided with a draw-in spindle with a #-inch Into this lathe, just as into all of the 1500 Gooddell- hole clear through. The pulley has four steps for %-inch Pratt tools, is built quality. Nothing in workmanship round belt. The compound slide rest, boring attachment, or material is spared which will in any way improve sawing attachment and milling attachment, showninthe Goodell-Pratt tools. The policy of designing each tool four circles below, are intended for use with to fulfil a definite purpose, and the determination to Precision Model Lathe No. 700. With these make every tool the best of its kind, has resulted in attachments an almost unlimited scope of | mechanics the world over demanding Goodeli-Pratt work can be accurately and quickly accom- Tools. GOODELL-PRATT COMPANY. Zefmiths, Greenfield, Mass. Sawing Boring Attachment— Attachment No. 720 91

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Alternating Current Motors” By A. E. Watson, E. E., Professor of Electrical Engineering in Brown University, Providence, R. I. This book contains complete in- structions for building small alternat- ing current motors in several sizes. The designs will be found_to be in harmony with those of the very best manufacturers. Important Information for Electricians Some of the subjects taken up are “ Characteristic features of alternating current motors,” ‘Construction of a one-half horse-power, single-phase induction motor,” “Construction of a one-kilowatt, two-phase or three-phase alternating current generator cr a one horse- power synchronous motor,” “Procedure in testing and using an alternating current generator or syn- chronous motor,’ ‘‘ Construction of a one-half horse-power single-phase com- pensated series motor.” Clear, concise directions and careful drawings are features of this book. 79 Pages, 47 Illustrations. Price, *1: BOOK DEPARTMENT Popular Science Monthly 225 West 39th Street, ~ New York City “The Construction - of Small Fastening Binding Posts to Carbon Electrodes in Cells N wet cells having carbon electrodes it is necessary to have the binding- post substantially joined to the car- bon, and the corroding action of the electrolyte, due to its creeping up and through the porous carbon on the binding-post where the latter joins the carbon, must be avoided. To do this is quite difficult, but a good method is as follows: Drill a hole in the carbon the size of the bind- ing-post screw, then enlarge the hole at the bottom, making it cone-shaped. This hole is then filled with a melted alloy consisting of two parts bismuth and one part tin, and the binding-post is screwed in before it becomes too hard. On cooling the metal expands, making a tight and substantial joint. To prevent capillary attraction and creeping of the electrolyte up the car- bon, the top of the binding-post in place should be dipped or soaked thoroughly with paraffin, wax, or in- sulating varnish.— PETER J. M. CLUTE. A Portable Tool-Board for a Shop or Plant a large refrigerating plant where repairs are likely to be made in any room or division at any time, the work- men found that it was almost impos- sible to select the proper tools necessary for each job and take them toit. As The tools are hung on the sloping sides and the whole is mounted on casters there was only one set of tools in the plant, they were arranged on an in- verted V-board mounted on a base having truck casters. When a breakdown occurred in any part of the plant, it was only necessary to push the tool-board to that spot, and all tools necessary were at hand. Preserving the Luster on the Surface of Silverware ILVERWARE may be kept bright and clean by coating it with a solution of collodion diluted in alcohol. The articles should be .placed in hot water, after which they should be thoroughly dried before applying the coat of collodion. Care should be taken to have the coating very thin, so that when dry it is almost invisible. 92 Popular Science Monthly ELECTRICIANS WIRING MANUAL SENGSTOCK a. Electrician’s Wiring Manual BY F. F. SENGSTOCK Electrical Inspector Chicago Board of Underuriters When youre up against a stiff job, let this book be your helper. It will tell you exactly what to do and how to do it in strict accordance with the National Electrical Code. The book that thousands of Wiremen, Contractors and Electricians have been wait- ing for. Not 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 how to pro- ceed so that your work will pass the most exacting in- spector. Every step ex- plained in detail, made clear by 415 careful drawings. Flexible Leather Binding, Pocket Size. Price $1.50, postpaid Popular Science Monthly 225 West 39th Street New York City

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January, 1919 . | “Lets Go!” That has always been the call of men who ride Harley-Davidson motorcycles, the call of leaders. They never la}. In war or in peace, the rugged dependability of the Harley-Davidson has drawn toward it riders of the trail- blazin3, type. Durin?, the war every Harley-Davidson motorcycle made became the mount of a man in khaki. These men and their Harley-Davidsons have established un- equalled records for continuous perform- ance; records in economy, upkeep, and de pendability of service; records no after- the-war business or personal demand can afford to ignore. —— — =~ =I as Iie nt il “Tit | “Ask the men in the service—they know’”’ t= | I= —| E| Ein EG = i} Y / —~ / =] Vi] ¥ = AN ES iil — ‘iT \\ fey ( : yt x f if iS } / ————=> SS}, / (es pita S ~ ————_— MW. S —Z - =. ~—_ usta - Dewignen Motor Co- -Milw aukee:- Wisconsin-:- 93

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seo tines ie tes SS — Se a me 3709 Cortland Street, THE BIG TWIN EXCELSIOR The Motorcycle That’ Made Good in the Mountain Passes of Italy quirements of Alpine service, and it made good. The enormous power and unfailing reliability of the Big X Twin Motor, the unbreakable double trussed front fork, extra large roller bearing clutch and nickel steel frame that proved the supremacy of the Excelsior on the Alpine battle fields are in every Excelsior Twin and in no other motorcycle made. If you want a motorcycle that will deliver the goods under all conditions, you -want an Excelsior. Write for catalog or see, the dealer EXCELSIOR MOTOR MANUFACTURING & SUPPLY COMPANY Manufacturers of Excelsior and Henderson Motorcycles and Sidecars With all the motor- cycles of the world at their disposal the Italian army experts selected the Excelsior as the one best adapted to the awful re- CHICAGO, ILLINOIS TOOL CHESTS If it is chests, we can supply you. That’s our business. Write for Circulars J. M. WATERSTON 81 Woodward Ave. , Detroit, Mich, Raise Belgian Hares for us. Wonderful profits easily made at home. We furnish stock and pay you a pair and express charges and buy all you raise. Also cavies and squabs. Beautifal illastrated catalog and contract 10c UNITED FOOD & FUR ASSOCIATION 329 West 48th St. Desk 4 New York SAVE 25% to 60% on slightly used GRAFLEX-KODAKS Gamers and Lenses of every deocrjotion. Equal Save money. Write no’ 1 rs in Book ona ae ees hundreds of money-saving bargains in 4 4) used and new cameras and lies. dealing with us. “hav. &- in the photo- araplie b business over 16 age Write now. CENTRAL CAMERA CO. Dept. 51, 124 S. Wabash hee CHICAGO A eer at Small Cost: Put a STEFFEY motor on your wheel. Made by the old- est makers of motor attach- ments inthe U.S. Most reliable, LN best hill climbers. Fit any wheel. Cash or installments. Critiatet descriptive circulars for stamp. excellent proposition for agents. r Stefley- Mfg. Co., Dep’t S., 5025 Brown Street, Phila., Pa. — REVERSIB Le ap Dg lh ag RO Bed REVERSIBLE COLLAR CO., Dept. A Boston, Mass, ’ Also includes A TRANSPARENT TRIANGLE, Submit your Song Poems NOW for free examination and advice. We revise poems, compose music of any description, secure copyright and em- ploy original methods for. facilita- A ting F PUBLICATION Post al or outright SAL. of songs Cord brings under a certificate you a copy of our GUARANTEE- Free Booklet w! which iells you who we ere, explains our methods and contains valu- R TE eble information and instructions. This is your opportunity to learn the truth regarding the Song-writing profession from a reliable and successful concern. KNIOKERBOOCKER STUDIOS, 88 Gaiety Bldg., N.Y. City GU SSONEANG re C "K TO-DATE DESIGNS FREE. . GROUSE CO. 123 ‘ian tl North Attleboro, Mass. Mathematics Made Easy The Arcascope—the Combination Triangle with a Brain—will multiply, divide, figure percentage and proportion, solve all problems in trigonometry and geometry, draw symmetrical figures, plot arcs, etc. Superior to any slide rule. Simple to operate. PROTRACTOR and THREE RULES. Used at Columbia University, West Point, U. S. Aeronautic Schools, Etc mly 85c postpaid. Order today before you forzet. Dept U, L. J. LEISHMAN CO. A Tooth Brush pro-P clean too Ogden, Utah. never * Seeeth clean Iny“ac mete — Popular Science Monthly Protecting the Automobile Top from Tearing N arrangement designed to pre- vent the tearing and stretching of automobile tops consists of a pair of coil springs placed between the top and the wid-screen. The jerks and strains A asian coil spring with pure and snap to take the strain from the cloth occasioned by driving over ruts and rough roads are taken up by these springs instead of being transmitted to the nails that fasten the top to the ° rear of the machine. All pulling out and tearing away of the top is thus avoided. —J. S. CHAPMAN. Open the Automobile Bonnet for Hill-Climbing HEN driven in a mountainous country, especially in summer- time, the Ford engine has a habit of boiling madly. This is, of course, due to the amount of low gear work it has to do: the slow rate of speed does not permit sufficient volume of air to pass through the tubes to cool them. Taking off the bonnet is an expedient frequently resorted to by Ford drivers, but it is an awkward item to stow away. If left at home, the driver is apt to need it to protect the spark plugs and motor from splashes when fording a stream or when passing through mud-holes. It is not always possible to stop and cool down every few miles, and a good compromise may be effected by opening one side of the bonnet only (naturally the side from which the wind is blow- ing). The open side may be tied back securely with a piece of stout string, and rattling may be prevented by placing a piece of felt in the fold at the forward end. - he Running Direct-Current Motors on Alternating Current HE illustration shows a method which will be found useful in running D. C. motors on A. C. circuits. Disconnect the field winding from the armature A and connect the brushes of the machine together. Then ar- range the field F of the motor in L|s A.C. SUPPLY Wiring arrangement for running a direct- current motor on alternating circuits series with a variable resistance R and the source of available alternating current. The resistance should be low for starting, but may be increased when the motor is running at full rated speed. a

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January, 1919 “Dickies Tine and the Blewienta? ‘GES: REUNAUY Motor Topping Re-Top with Drednaut Elegant in Appearance A Drednaut top will add to the beauty of any car—making an old car look like a new one. Durable and Weatherproof Often outlasting the car itself, a top of Drednaut will protect you from the severest storms or the hottest sun. Drednaut’s Reputation We sold top material long be- fore motor-cars were made — leaders in manufacturing since 1847, Drednaut is one of our several sterling products. Write for samples and particulars L. C. CHASE & CO., BOSTON NEw YORK DETROIT CHICAGO SAN FRANCISCO Leaders in Manufacturing Since 1847 A Home-Made Candlestick that Will Not Upset HE half of an old metal globe or a cup-shaped section of light metal can be turned into a convenient candlestick by denting in four spots on the sides as shown and then pour- Handle An old metal globe makes this attractive base for a candlestick ing in enough plaster of Paris to form a candle socket of sufficient depth. The dents produce projections on the inner surface to hold the plaster. Before the plaster has set press a new candle into the center of it and let it remain there until the plaster is hard. This forms. the socket. A more finished effect can be produced by riveting sheet metal handles on as shown in the illustra- tion.—JAMES M. KANE. A Switch for an Adjustable Condenser Circuit HE device described and _ illus- trated herewith is an easily con- structed switch for use with an adjustable or variable condenser. Its construction and details are simple, and it is so built that it will not get out of order very easily. The square base is made of wood, and the movable contactor consists of a large fiber washer and half of a brass washer, as shown, so fitted that there will be an even surface. The con- tacts, which are connected underneath i y SS ia * ~~ iene WH mM +A, Hat ‘fl Wl Fiber washer with a semicircular brass disk mounted on a wood base for a condenser circuit to the condenser terminals, are made of brass strips cut and bent into shape, to bear on the movable washer. The method of connecting the switch to the condenser can readily be seen here.—PETER J. M. CLUTE. 95 +t Mis like the hide in most respects In some respects tis better, Made by Sanford Mills FOR UPHOLSTERY ‘HIS is the scientific fabric which the United States Government purchases for upholstery purposes. It meets every requirement of durabil- ity and appearance. Conservation of genuine hide is neces- sary —to economize re-upholstering is urged. Furniture and motor cars can be readily improved by new upholstery and CHASE LEATHERWOVE is the logical choice. FOR FURNITURE—Rich appearing — cleansed, sanitary, long-wear- ng FOR MOTOR CARS— Harmonious colors and patterns—weatherproof— durable. These two grades for Upholstery: Leatherwove Galloway Leatherwove Gibraltar Other grades for scores of uses. L. C. CHASE & CO., BOSTON NEW YORK DETROIT CHICAGO SAN FRANCISCO Leaders in Manufacturing Since 1847 OES Meret Sigil AE Sa RR

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Apparatus for Sending Wireless Messages from Airplanes ICTURE yourself speeding aloft P in a wireless-equipped airplane with two officers of the Signal Corps to obtain information that will silence an enemy battery. The day is clear, but it is difficult to locate the guns because of the camouflage. Sud-

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Dynamo Diagram of connections of a Telefunken airplane wireless as used by the Germans denly a bomb exposes a suspicious bit of landscape. “There they are!” cries the observer. The others look in the direction in which he points. Far below they see what he has discovered—the well- masked muzzles of the guns that have caused so much destruction. Even the soldiers manning them are momentari- ly in sight. The observer quickly turns to his wireless set and signals headquarters, telling just in what direction he has calculated the gunners’ fire should be directed. Almost within the instant the hand of the operator leaves the transmitting key a veritable hail of shells begins to fall about the battery. . They just fail to reach their mark, however, so the observer sends another message to headquarters—new direc- tions for aiming. Then the fire is swung slightly to the left and directed squarely on the objective. The wire- less has accomplished its mission, and the airplane descends to the earth. An inspection of the radio apparatus in the airplane shows that it is some- what light. Mounted on the forward part of the flying machine is a tapering metal case, hardly eleven inches long and about six inches in diameter, yet this contains an alternating-current generator of two-thirds horsepower and a direct-current dynamo to excite the alternator. When the airplane is in operation the propeller is driven around 4,500 times a minute. The dynamos on the same shaft whirl around with it, and are thus made to go around ten times as fast as the wheels of an automobile traveling at forty miles an hour. The alternator does away with an interrupter on a spark coil. The rapidly reversing current is led directly into the transformer primary. The current emerging from the secondary winding, now stepped up to a very high voltage, finds itself first charging the plates of the spark gap and then overwhelming the air resistance and breaking through in the form of an electric spark. The condenser in the circuit shunting the gap has in the meantime received a charge also, and the spark has helped to close the cir- cuit containing the pancake induc- tance, the gap and the condenser. Following the rest of the circuit, it is observed that the pancake is tapped directly onto the antenna and ground. The antenna consists of a reel of wire back of the observer’s seat. This is unwound as the airplane takes the air and the antenna is lowered about 135 feet. A metal bobbin on the end of it keeps this wire from fluttering as it is swept almost horizontally in a long graceful curve by the wind. The “ground,” on the other hand, is merely the wire stays between the planes and inside of the canvas covering of the wings. The controls by which the operator tunes his set are on top of the instru- ment case mounted at the front of his compartment. With the first control he is able to change the power from the alternator from low to high as he gets farther and farther away from his lines. When the switch is thrown to high, the spark-gap length is in- creased automatically, so that he may be sure that the spark will work as efficiently as before. Throwing the next control simply adds or subtracts Alternator... AL.collector rings, D.C. dynamo

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Propeller Resistance box in system Air cooling.” _ alternator field system Plug to lights on airplane Instrument boards 7° +------- This type of generator has two dyna- mos mounted on the same shaft some of the pancake’s inductance so that any of the three wavelengths of 150, 200 or 250 meters may be quickly obtained. By this means, should the airman wish to report a maneuver he has discovered to a station, other than his own, he changes to the different 96 / -D.C.commutator Popular Science Monthly wavelengths of that station. Every time he does this he varies the induc- tance in the antenna circuit slightly until the ammeter in the same circuit shows that the greatest amount of - power is being radiated. This, then, is what you would have to be familiar with if you were an officer of the Signal Corps detailed to airplane observation work. But then, you may say, you have not been told how the receiving is accomplished. The answer to this is that it is not the usual practice. It can be done, but the added incumbrance to the aviator and the necessity for increasing the complexity of the system to overcome the noise from the engine and the rush of the air are advanced as argu- ments against it. The observer is given his orders before ascending. These he. must fulfill to the letter; furthermore, he is expected to use initiative in the “tight places’’— when, for instance, he is menaced by anti-aircraft guns or enemy wireless men “‘Jam” his messages.— LLOYD KUH.

& “@ © 0:0 @ i. The letter P is fcrm- ed with the -coins Premonition Trick—Which Was the Last Coin Counted? RRANGE 19 coins in the form of the letter P. Tell your friends that while you are out of theroom they Zz Vv are to think of any % ¢ e = number and count & it out on the coins. You will return @ when they are & ready, and tell ex- actly what coin was ae ae & last counted. ee Of course, they must begin count- ing at X, and fol- lowing the upright in the letter to Z, out toward V, then back down to Y, where the count goes out toward M. Suppose the number should be 12. Begin at X, and count 12 coins, which takes the count to V. Now start back and count 12, which brings the count to M. Take any number you desire, and do the same, and you will find that the count always comes at M. The location of M will always be easily found, because there are as many coins between Y and M as there are between Y and X. Of course, it is necessary to change the number occasionally between X and Y, so that M will not come in the same place every time. Even if the number chosen is above 19, the trick will work,.and the back count will come at M for the last coin. It makes a very puzzling trick for those who do not know how it works. Tell your audience that the coins must be arranged in the shape of the letter P because you tell which is the last coin by the instinct of premonition.—F. E. BRIMMER.

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January, 1919. Bm a ny eR BE CT oa OO mw D —h DOD RD ec mem UW Crm ¢ ek ie —Oo-s A O © al ~ ae X e ny & “Tit Ce et tei ete ii li A i 6,003 Burlingtons have been sold to the men aboard the U..S. battleships. Practically every vessel in the U. S. Navy has many Burlington watches aboard. Some have over 100 Burlingtons. The victory of the Burlington among the men in the U. S. Navy is testimony to Burlington superiority. A watch has to be made of sturdy stuff in order to “‘make good’’ cn a man-of-war. The constant vibration, the extreme heat in the boiler rooms, the cold salt air and the change of climate from the Arctic to the Tropical are the most severe tests on a watch. If a watch wi!l stand up and give active service aboard a man-of-war, it will stand up anywhere. 5 a $50 Burlington A Month And yet you may get a 21-jewel Burlington for only 32.50 a month. Truly it is the master watch. 21 ruby and sapphire jewels, adjusted to the second, temperature, isochronism and positions, Fitted at the factory in a gold strata case, warranted for 25 years. All the newest cases are yours to choose from. You pay only the rock - bottom - direct-price— positively the exact price that the wholesale dealer would have to pay. ¢ $ You don’t pay a cent to anybody until you see the watch. We S €eé t f[ iy Lr. & f 3 ship the watch to you on approval. You are the sole judge. No obligation to buy merely because you get the watch on approval. Write for Booklet! | — Put your name and address inthe couponoronaletter | or post card now and get your Burlington Watch book frec F and prepaid. You will know alot more about watch buy- ke ing when you read it. Too, you will see handsome illus- trations in full color of all the newest cases from which you have to choose. The booklet is free. Merely send your name and address on the coupon. Burlington Watch Company, 19th Street and Marshall Bivd., Dept. 1201 ‘Chicago, Illinois Canadian Office: 355 Portage Ave., Winnipeg, Man. Sn ies aN fy Burli Watch Co., Dept.1201, eur Ote Street & Marshall Blvd, Chicago, I, 1 d ithout. obligations ‘and_ prepaid) * ties babk on see belies peice x: ; $2.50 a month offer on the Burlington Watch, al ~- Name

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WHY DON’T YOU GET AN AUTO-WHEEL? FrELLows who know will tell you - that the Auto-Wheel Coaster and the .Auto-Wheel Convertible Roadster are thie best wagons ever built for speed and . strength. Wheels have roller bearings, steel. J axles and‘ tires, — the spokes are oval, = an ‘auto, ‘ Send Per Free Felt a Conane ¢ Write us pames of three oparten . ers ana et a ‘you"a elt Pén nant FREE. e will also celle vie ‘how: to organize a Coaster Club.<It’sgreatfun, Each member receives a cap“and the captain'a ‘special cap. Write today. BUFFALO SLED COMPANY : 157 Schenck Street - N. Tonawanda, N. ¥. ; (in — Preston, Ont,) ordeal. 5

BENJAMIN = Speaking of air rifles, why not buy the best and safest? Only real pump gun ever invented. nlike all others, it never loses shooting force. Man and boy’s gun for target practice and small game hunting. This pees inch block of wood shows the various degrees of shooting force. This is a feat no other air sifle can duplicate. Price $3.75 Postpaid in U.S. Descriptive folder on request. Ask your dealer for demonstration. BENJAMIN AIR RIFLE & MFG. CO. 607 N. Broadway, ST. LOUIS, MO.

SA WEEK t Fy a ots = pani Haverford Cycle Co. (st. 22 yrs.) pet. Gas ERE seis 2 New i919 Catalog ¢ colors

Woriilzer “in clei ot master ad he moder aa Unequaled Write te for New w Catalog fx chelgeoncan af Ano viene at off pofeze, By oeemes, The Wurlitzer 201 S.Wabesh Ave. Se 0.

HEN a current of : ae \ \/: “passes through a conductor, it - encounters a certain amount of resistance. In overcoming this re- sistance heat is generated. Along with this production of heat there is also frequently light or motion. The heat developed is proportional to the square of the current, directly proportional to the resistance and directly in propor- tion to the time. Thus, if the current is doubled there will be four times as much heat developed as was pre- viously generated; and,‘if the current Crucible of refractory. remains the same "lerial holding i a

Popular Science Monthly 2 Electrical Devices and How They Work XIII.—How the resistance encountered ~ in the conductor generates heat By Peter J. M. Clute, B. C. consequence, in rheostats and in elec- tric-heating apparatus, where a high- current density or an intense heat is desirable, the wire is embedded in cement, enamel, or other substance, which not only insulates the conduc- tors, but also excludes the air from around them. The incandescent lamp affords an example of the advantage of excluding air from a highly heated conductor. If even a very small amount of air remains in the bulb the life of sual lamp will be much shortened; ifafilament should be exposed to the air it would im- Fireclay slab rd covering

and the resistance is doubled, there will be twice as much heat as be- fore. When sinaialadeer flows through a mediately be con- sumed. The resistance wire in rheostats and electric-heat- ing devices, if prop- erly protected

conductor the

from air, may be

equal to I?-Rt, where I repre- sents amperes, R ohms, and t seconds. All this work is converted into heat energy, which raises the tem- perature on the conductor and its surroundings. Transmitting the Current In the generation and transmission of electrical energy this production of heat is very undesirable, and is avoided as much as possible by using conduc- tors of low resistance or by transmitting the energy at high pressure and cor- respondingly low current. Ordinarily the transmission work, the size of the conductors to be used, is determined by the allowable pressure drop rather than by the heating effect of the elec- tric current; but it is sometimes neces- sary to consider also this heating effect. The fusing effect of a current de- pends on the readiness with which heat can escape from the wire. If a very short wire is clamped between termin- als, heat will escape to the wire; if a fuse is installed where air circulates freely, the air currents will carry away the heat. .For these reasons, fuses must be of sufficient length so that the heat imparted to the terminals cannot appreciably change the melting-point; they must also be installed where air currents cannot affect them. Fuses, therefore, are usually 1 in. or more long, and are inclosed. Difficulty of Good Insulation In the absence of air, a conductor will carry a much larger current with-

out fusing than if air is present. Asa a ;

work in joules ig st Figure 1 A simple form of an electric furnace consists of a crucible with a fire brick housing operated at red heat without mate- rial injury; but this is seldom done, because it is difficult to maintain good insulation at such high temperatures, and, any way, such intense heat in these appliances is seldom necessary. In every kind of work that electrical energy is called upon to perform, re- aistance, and consequent waste by heating, must always be reckoned with; and in every kind of work, except electric heating, it must be reckoned as aloss. Electric heat is the one kind of work that electricity does in which re- sistance is a good thing—indeed, the essential thing. Uses for Electric Heat In the electric light—arc, incandes- cent, or any other kind—it will be noted that the light comes from solid or gaseous conductors that are raised to a white heat by passing a current through ~ them. In order to get the light from such electric lamps, a good deal of heat energy is generated along with it— in fact, most of the electrical energy is transformed into heat and only a little into light. In making electric heating apparatus, however, it is not light, but all heat, that is desirable; and the effect of electrical friction, which is such a waste and loss in all other electrical devices, is here the very es- sential thing. Thus, as far as efficiency is concerned, electric heating devices are superior to any other kind of electrical apparatus. Electric heat is now employed for the following principal uses: (1) to operate electric furnaces in the art of electro- metallurgy; (2) in electric welding; (3) i

VJanua jn the bath; water plianc nume ances A gical the: t elect prod and ¢ the « duci1 as fu meet chen W acro: elect The est ¢ hooc furn an | stan Car) elect ‘heat is st cibl:

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2lec- ‘igh- it is 1 in nce, duc- Tom amp re of ated mall the ned; ould the im- con- ance stats eat- TOp- ted y be red ate- but lom it is n at vay, 2s ig “ical Te- by ith; sept d as d of Te- the les- (0 a ‘ing but the 1 is cher ncy ices of the sate tro- (3) “January, 1919 in the electrolytic forge, or tempering path; (4) for air-heating devices; (5) for water-heating devices; (6) heating ap- pliances for domestic use; and for numerous other miscellaneous appli- ances. A great variety of electro-metallur- gical processes can be accomplished by the: use of the electric furnace. The electric furnace has the advantage of producing a very high temperature and of being under easy control. Since the carbon serves merely as the re- ducing agent, and not at the same time as fuel, its quantity can be regulated to meet the requirements of whatever chemical reaction it is desired to secure. When the current is made to flow across an air gap between two carbon electrodes, an electric arc is produced. The temperature of the arc is the high- est obtainable, being in the neighbor- hood of (3500° C.); and in the electric furnace, in which the arc is confined in an inclosed space, any known sub- stance can be melted or vaporized. Carbon is nearly always used for the electrodes, as it will best withstand the ‘heat. A Simple Electric Furnace A simple form of an electric furnace , is shown in Fig.1. It consists of a cru- cible of refractory material surrounded Pieces to be welded 4 # a i} Water cooled Alternator pressure clamps Transformer (4 Adjustable LJ Lif 0 Switch resistance Figure. 2, A diagrammatic view of the Thompson proc- ess, the one most commonly used for welding by fire-brick, and is covered with a fire-clay slab. Carbon rods enter from each side and form the electrodes, the . arc being started by sliding one carbon in until it touches the other and then withdrawing it. The great usefulness of the electric furnace is due to the ease with which its temperature can be regulated, also to the intense heat obtainable. There are three general types: the reflecting are furnace, in which the heat is re- flected upon the charge by a reflecting surface; the direct heating arc furnace, in which the materials treated sur- round the arc that imparts heat di- rectly to the charge; and the incandes- cent furnace, in which either the charge or the furnace wall forms-a part of the . circuit, and by the resistance offered to the passage of the current produces the oO You Must Get Ahead or Go Back! A dollar today buys less than it did a year ago. You MUSTearnmore money oryou’re going backwards. Equip yourself now with knowledge that places you in the $2500 to $5000 a year class! The machine shop and the automobile fields hold limitless opportunities for men who KNOW. Boost your pay through reading one or both of these wonderful libraries. Auto Books Shipped © OE ; \ Primary a 4 fotos Modern Shop Practice Six splendid volumes bound in flexible American Morocco, gold s' pages, size 5 1-2x 8 3-4, illustrations, photographs, drawings, diagrams, tables--eve: bog, Hes make it easy for ‘ou to learn. Prepared by 27 Mechanical Engineers igners, and specialists in shop methods an management. Describes simply, practically and clearly, the simplest operations of machinist, tool maker, designer, pattern-maker, foundry man, as well asthe newer and complicated details of me- h 1 development--speed lathes, planers. mul- tiple drillers, grinders, milling machines, stamping machines, die presses, and the Rha tools and dies which go with them, Tells all ut machine shop work, gear cutting, metallurgy, welding, die mak- ing, metal stamping, tool making, tool design, foundry work, malleable practice, forging, heat treatment, pattern making, mechanical drawing, machine drawing and design, automobile shop work. All written for home study. So simple and prac- tical that any one can understand. Special price, $19.80 on terms of $2 a month. Send coupon for free examination, Automobile Engineering Five wonderful volumes covering construction care and repair of pleasure cars, motor trucks, an motorcycles. Brimming over with information on’ lighting systems, garage design and equipment, welding and other repair methods, Contains every- thing that a mechanic, engineer, motorcyclist, owner or prospective owner of a motorcar ought to know. Written in simple language that any one can understand, Tastefully boundin American Morocco, flexible covers, goldstamped. 2400.pages, size 61-3x 8 3-4, 2000 illustrations, tables and ex- planatory diagrams. A library thatequips youfor the biggest paying positions in- the automobile field. You study at home in your spare time with- out interfering with your present work. - Tells all about explosion motors, welding, motor construction and repair, carburetors and settings, valves, cooling, lubrication, clutch, transmission, steering, frames, tires, vulcanizing, ignition, start- ing-lighting systems, wiring, diagrams, ccmmer- cial garage design and equipment, electrics, storage batteries, motorcycles, commercial trucks, Every- thing. new and right up-to-date. Special price $17.80 on terms of $2.a month. Send coupon for free examination, Not a cent to pay in advance Oo on ey for either set. See the books in your own home or shop. s Just mail coupon and pay ex- in vance press charges when books = arrive. Don’t waste a mo- mentin mailing the coupon for either or both sets. No money in advance. Pay {2 Zea Day je riecc if Pleased (eine myers: thousands of dollars to gain. Mail coupon now. heat effects required. The ditect heat- WITH EACH SET WE GIVE A YEAR'S CONSULTING MEMBERSHIP IN THE AMERICAN TECHNICAL SOCIETY. Regular Price $12. Send no money now. See the books without sending us a penny in advance. Don’t miss these thousands upon thousands of salary boosting facts. Mail coupon NOW. AMERICAN TECHNICAL SOCIETY, Dept. SP1201, Chicago, U. S. A. . N 6 Mail Now! AMERICAN TECHNICAL SOCIETY Dept, SP1201 ‘Chicago, U. S. A. ° fj Please send me shipping charges collect set 08s ees FERS ee eee aide {819.0 for Modern Shoo Praetes) (20 for paid. .80 for Modern » ($17. Automobile Engineering. Ten soo wil send me a receipt showing the set of ‘and: the.$12 = ing Membership are mine and fully paid for. If I think I can get along without the books 7 days* examine aticn, I will return them to you at your expense, Name Address : 4 Reference sens eee . ———

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Sy ees ae Pin ase aed 45 Neds 400 New Ideas for Motor Car and Truck Owners This is iy ‘ehatice to a the greatest book ever published for owners and users of motor cars and motor trucks. It pictures and describes all the new accessories.and all the new devices for sav- ing fuel, tires and engines. It gives many prac- tical new ideas for remodelling bodies, converting old chassis, making economical repairs. Over four hundred new ideas are described and there are over. four hundred photographs and other illustrations. The book is edited by the best known automobile authorities, and is re- liable and practical. Tractors, trucks and trailers, business cars and pleasure cars,.all are included in the rich contents of this volume. . The 1919 Motor Annual of Popular Science Monthly will be published about January 20th. Only a limited ‘edition will be printed and you should order your copy right away to make sure of getting it. Use the blank be- low. The price is very low for so big and valuable a book. Here are a few of the automobile parts and accessories for which new inventions or new ideas are given in the Motor Annual:—Windshields, magnetos, chains, lamps, inner tubes, mud hooks, jacks, truck bumpers, safety locks, heating devices, clutches, brake bands, water pumps, tire pumps, gasoline pumps; mufflers, grease guns, spark plugs, radiator fans, shock absorbers, pistons, automatic door openers, cold weather devices. Dozens of articles give specific directions for getting in- creased efficiency from engines, head lights, oil, gasoline. Many ideas for economical home repairing are included. Price—35 cents, postpaid. Cut the coupon and cut your motor costs Popular Science Monthly, 225 W. 39th Street, New York, N. Y. Please save me a copy of the 1919 Motor Annual of Popular Science Monthly. I enclose 35 cents—Send, postpaid when issued, about January 20th. Popular Seience Monthly ing and the incandescent furnace are the types most frequently used. In the ordinary process of welding materials the parts to be united—say two bars of iron—are heated in the forge and then hammered together, Electric welding works much more quickly, and the joint is as neat. Moreover, it can weld certain met- als that cannot be welded by the old method, and it can weld together two different metals. The Welding Process The process consists in simply press- ing together the ends of the pieces to be welded and passing a very strong current through the point of contact. An alternating current is generally used, because a heavy current at low voltage ‘is more easily secured by using an alternating current trans- former of special design rather than by employing a direct-current dynamo, The heavy current finds a resistance to its flow in passing from one bar to the other where the bars touch, and generates an intense heat at that point. .The metal becomes white hot Positive “Tempering — Metal to be Negative ba ay iterminal = tempered 3 Metallic Figure.3 A cross-section of an_electrolytic forge, showing the electrode in the water bath in an instant, and it is only necessary to force them together to make a true welded joint. A special machine, called an electric welder, is used. It has heavy copper clamps to grip the pieces to be welded, and an arrange- ment of levers to press them together at the proper moment. The Thomp- son process, which is more generally used than any other, is illustrated in Fig. 2. Only a very low voltage is needed in the secondary circuit, but a current as high as 60,000 amperes to the square inch may be necessary in welding some metals, as, for example, two copper pieces. A low frequency~—50 cycles or even less—is preferred, especially for heavy work where the current density is very great. The time required for making a weld varies inversely with the amount of power supplied; that is, the greater the power the shorter the time of the weld, and vice versa. Metals that are deteriorated by being heated, such as brass, copper, and tool steel, must be welded rapidly. The pressure must be great enough to crowd out from the weld all metal harmed by the heat. Rh Se on

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@® © Oe OS OW ee Ss SS 6 We @ rTtmOoO OD ef t

January, 1919

Ors ested

Play Any Instrument aWeek on Free Trial! : You may take your choice of any of the instruments in our big, new catalog and we will send it to you for a week’s free trial. We want vou to compare it with other instruments— and to put it to any test. We want you touse it just as if it were your own. Then, if you wish, you may return it at our expense. No charge is made for playing the instrument a week on trial.

WURLIIZER | 200 Y : If you decide to buy— you may Convenient Monthly Fi ay ments the low rock-bottom price in small installments, if you wish. $4.00 a month will buy a splendid triple silver-plated cornet. You Z will find over 2,000 instruments in our catalog. Every one is backed by our guarantee. Every one is offered to you on the same liberal plan. The name of Wurlitzer has been stamped on the finest musical instruments for 200 years. Wurlitzer has supplied the United States Government with trumpets for 55 years. We are specially prepared to assist in the formation of bands or orchestras. | Send the Coupon Send your name and address on the coupon (or in a letter or post card) and get our new cuae. It takes 160 pages to show you the instruments from which you may choose. The catalog is sent free, and without obligation to you. Leng 4 state what instrument interests you—and send your name. Don’t delay—do it today, RIGHT NOW. The Rudolph Wurlitzer Co. So. Wabash Avenue, Chicago— Dept. 1201— E. 4th St., Cincinnati, 0,

The Rudolph Wurlitzer Co.

catalog, absolutely free. Also Special offer direct from manufacturer. Gentlemen:—Piease send me eo pout 160-page Name

Street and No. ...

City Lecene scabs © bashdn tapduciieasipines <pebentnehess Gini GREE .<. iin <sintticutaiaieania

eum interested £20. cccc.. on eeb ic pisinsesiccn tei ngueet pene _ bes . “ (Name of instrument_or band or orchestra)

101

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- Herman | Fine Gun Metal U.S. Army Last For Givilians \ \ JAR has taught business . men and industrial. men the priceless lesson of U. S. Army shoes for comfort and * | foot-health, Herman Shoes go several ° % degrees further by embodying * all the anatomic features of the Army last, and, in addition, supplying the fine appearance and service features % legitimately demanded by civilians. eee a ——— > ae Herman Shoes give menin * all branches of active life the perfect opportunity to enjoy the full, normal efficiency of their feet and to indulge their individual. desires for fine leathers and 100 per-cent wear. * Sold in 8,000 retail stores. If you | ee =—— ee are not near one, we will fit you correctly and quickly through our - MAIL ORDER DEP’T at Boston bs JOS. M. HERMAN SHOE CO. 802° Albany Building BOSTON, MASS. gn bE OTTAWA. *2-27 Kerose:.> ENGINES. er Bate oe om orl cent gasoline in any gaeclie to operate. Ail Sizes and Styles, cacy to part eney Shipped « © Bought from LS Stock = rai Lothes. | mail $3.00 cash oF Money Order We SACOD meet 00 GAS. 0. JONSON - West End ~Fitsborgh,P. aA. = oy The Classified ts are on pages 106. 109. eee oe eee Oe ee and eutenly or legitimate and mutually oe tile - gree of heat can be An electrolytic forge, or tempering ‘bath, consists of a vessel lined with metal containing water or a suitable solution. wx |.The solution is made the positive electrode of a direct-current generator, while a piece of metal to be heated and tempered is made the negative electrode. This device is illustrated in Fig. 3. The liquid is contained in a vessel that has a metal lining to which the positive side of the circuit is con- nected. The piece of metal to be heated rests on a contact-bar, to which the negative side of the circuit is con- nected and extends to the liquid. The simple action of the tempering bath is as follows: When the metal to. be heated and tempered is plunged into the liquid and adjusted to the rod, a current begins to flow through the liquid to the rod, and a layer of hydro- gen gas immediately forms around the submerged portion. This layer of gas introduces so much resistance be- tween the liquid and the metal that intense heat is thereby developed at the surface of the metal. By adjust- ing the current strength and the time the current is allowed to flow, any required de- obtained, even to melting the metal. Suitable insulating shields placed over portions of the metal prevent the . development of heat on surfaces that are not tobetempered. The heating is under such perfect control that the tempering may be carried to any desired depth from the surface of the metal. Electric Heating Systems General heating by electricity can ° be carried out by three different sys- tems: by radiation, in the way that the sun warms the earth; by convec- tion, by which is understood the direct heating of air by contact with a heated surface; and by conduction, which is the effect produced upon solid objects that are in contact with others at a higher temperature, the heat traveling along the material and warming it. The last named system is made use of only to a small extent, but a certain amount of conducted heat is given off from any solid body that touches another solid body at a lower tempera- ture, and every heating appliance gives out a greater or less proportion of its energy in the form of conducted heat. In all electric heaters the heat is developed by the material contained in the appliance passing through some form of resistance. They may be broadly classified as follows: first, luminous heaters, or radiators, second, non-luminous heaters, or convectors; third, red glow heaters. In the luminous type of heaters the heat is obtained from two or more long cylindrical carbon filament lamps, especially designed for the production ‘of heat rather than light. These 102 Figure 4 Non-inductive effects are produced by making the current flow in a zigzag path Popular Science Monthly lamps are “mounted in a metal case a opened at the front with a polished - metal reflector in the back. Heat is imparted to the containing bulbs of : the lamps, and thence by ast cine to .— the surrounding air. How Heat Is Obtained In the non-luminous type, heat is 3 obtained by the passage of current | through bare wire or metal strips of high resistance, wound on tubes or frames of porcelain or other highly re- fractory substance, each tube or frame | forming a heating element. Several heating elements are contained in a | metal case from which they are in- sulated, and they are coupled together by short wires so as to form continuous lengths of high-resistance material be- tween the two terminals of the heater. - In the red glow heaters the heating element is formed of a thin high-resist- ance wire spiral contained in a quartz tube. Several of these glowers are fixed in a frame, INN and the frame is mounted in the | open front of the metal containing AN case. Quartz is as transparent to heat as to light, hence the bright red glow of the spiral wire inside the tube is not only visible, but the heat from it passes out tothe surrounding air. A large surface of red-hot quartz is thus obtained, giving an efficient radiator of cheerful appearance. All electric heating devices may be classified into lighting circuit and heat- ing circuit devices. The lighting cir- cuit devices are those that take about 5000 watts or less and may be con- nected to the ordinary branch circuits without any special wiring. The heat- ing circuit devices require special cir- cuits, as ordinary branch lighting circuits are not of sufficient capacity. In such devices the heating circuits are arranged as closely as possible to the surfaces to be heated, so as to make the efficiency of conversion from electricity into useful heat as high as possible. Generally, each manufacturing com- pany has adopted a distinctive method of making andinsulating the resistances. All heating resistances for use with alternating current should be non- inductive, as the production of heat depends only on the square of the cur- rent and the ohmic resistance; induct- anee would cause voltage losses that would result in no additional heat. Non-inductive effects are produced by making the current follow a zigzag path, as suggested in Fig. 4; or, if the resistance is in the form of a helix, by making the winding such that the cur- rent must travel an equal number of times each way around the helix. The applications of electric heat are very numerous. It is important to remember that the “‘same kind of elec- tricity”’ is ‘used alike for lighting and ra > genera atresgemenadis Januo

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StopSnuffling Sneezing, hawking, spitting and coughing. Why do you. have catarrh anyway? You were not born hi eee contracted it. soniiae complaint fastened itself upon you and grew. Na- ture in trying to prevent more serious consequences due to the congestion in your body, finds an outlet for the accumulated waste, by way of catarrh. You cannot get rid of it the way you are going— sprays, lotions, snuffing powders, drugs and medicines won't stop it. You know catarrh leads to other troubles — serious ones — throat, lungs. stomach, intestines—all be- come affected. You can never en- joy good health if you have catarrh; you won't be efficient in anything as long as you have catarrh, and it detracts from your personality to be hawking and snuffing around others. Build Yourself Up Be Clean—Wholesome—Healthy —Virile. Goat it the right way— Nature’s way; no drugs, no medi- cines, and you banish catarrh from your system. Let meshow you how by my method of health building, body developing, called STRONGFORTISM Its practice never fails—it builds new tissue, te brawn and a STR it invigorates heart action,strength- The en nay ‘all ens kidneys, and makes the bowels move bytheir own natural strength, it makes every organ in your body pulsate to health. Under this kind. of influence, catarrh quits for good, so will constipa- tion, nerv SS palpitation, rupture, rheuma- tism, weak heart, poor memory, physical weakness, vital losses, short wind, and all sorts and kinds of ailments and disorders. If you are too stout or too thin, flat chested, or round shouldered—Strongfortism will alter it. It will make you Ygrow in vigor and virility—and nervous energy—it will restore your vitality and keep your forces vital. No matter what your condition is now, or what habits you contracted or indulged in—I will show that you can renew yourself. You want to be strong, healthy—a virile man—you want to be all that a man ought to be and I can and will show you ag to make yourself the man that is desirable from every standpoint. Tell me your ailment and send three 2c stamps to cover mailing expenses and I will send you my book ‘*‘Promo- tion and Conservation of Health, Strength and Mental Energy,” written for your interest. and welfare. LIONEL STRONGFORT Physical and Health Specialist 732 Park Bldg. Newark, N. J. = Build“and Fly Model for heating, although different prices may be charged for the two services. The reason for a distinction in prices is based on economic considerations too complicated for discussion, the ‘general idea being that, as a rule, when the demand for artificial light is least it pays the central stations to offer energy at low rates in order to en- courage its use at hours when little power would otherwise be demanded. (To be continued.) An Automobile Horn Attached to the Frame Out of the Way O place the horn out of the way of the driver, an extension-rod for the push-knob was applied as shown in the illustration. The horn is placed lon pipe “S=sSS—_{— coupling Horn plunger Auto’frame The automobile horn is placed on the frame out of the way and is worked x War Aeroplanes! Build a Model Aeroplane that will fly like areal one. With IDEAL Scale Drawings and Building and Flyin: Instructions you can easily build exact ate _ Gaplicates of War-famous Aeroplane Send now for Drawings on the frame out of the way, and the horn plunger is lengthened with a rod by an extension rod on the push-knob Curtiss Military Legg fh wee riot onane png joplan: Sy, ‘Mono Curtis: a. Flyin, Wright Biplane, Cecil Peo! ro Catalogue of IDEAL Model Aeroplanes and Supplies, 5c. None Free. and Instructions for the one you t god Tost you wan which carries the push-knob at the top. A bracket is attached to the seat arm and a coil-spring placed between the bracket and the knob.—P. P. AVERY. IDEAL AEROPLANE & SUPPLY CO., 80-86 West Broadway, N. Y. m24 UYSA GIBSON 72«, DAY BUNS AGIBSON $2. '$2.20 per month. Ms Man lin: Se pe change rlallows 7 Gibson. ot strumen iti 100 500 BOOK. “Valuable ft for Play er teach ith ed an moet jon ciate wil aivarine A rr doltar poe 3 either sex pageeee ene Become Web sell, Territory protected. Ly = Seeks. the You make profit. You pay fo is when sold; return Hie 4 Dot ool apart our “sui i] posi oAREE to those. ine our new ion and Maintenance of the fin Orchesten " Amer rector, W Catalog, How to Cut a House Number in a Board HE house number shown is for the consideration of those who like something a little different. It is made of a piece of board 5 in. wide, 2 ft. long, and 34 in. thick. The numbers are sawed out with a compass or key- ea Wiite now. inewh Pictures| BY ELECTRICITY A complete set of two machines of this marvelous equipment for only $19.50. Instructive, mystifyingand use‘ul. This picture of President VWil- -80n was telegraphed by these machines. Picture telegriphing is the coming Science. Write today. L. J. LEISHMAN CO., Dept. H, Ogden, Utah OIL SEALING PISTON RINGS P' f your jerber / gies Be. fears WwosILe Acces ane i nick, Write fo or Ma. The house number is cut from a board like a.stencil and hung in the porch hole saw... The board-is for hanging from the front edge. of the -porch; in such a position the number may be read as easily at night as in the day. Care should be taken to. have the ties that hold the central portions of the figures run with the grain of the wood, as shown. -If put in across: the grain, they are, of course, easily Youcan’t dodge the fact that you can’t + succeed without train- ing—or that you are not paying dearly for pie et DS DON’T . Success— 5 bie pay— ope Dost tions —on trained weckdia™ You must tr: See : , cxpense, Start to Why Not siugy with the distinc: Try it2 you do not feel you are ni “mM. et eee not ‘make good. WILL YOU TRY for" Whether you need Specialized Instruction in yourchosen line, or if you lack Hi School Schecl athe baie et ettain anes ool on asis of satis n back. If we make good YOU MUST. =— Make idle Hours Devote: some of Bring You Success ‘= tive TAIN, ‘Gat to home me study’ dy and | SUCCESS S CER- we noe our mag tem of students. Do your- self @ favor by checking and mailing Coupon todas. AMERICAN ‘genta of Dept. aN tS sr ate Beplain bow 1 how I = an gual enee Tigh School Gone eid Civil Engineer eweMlectrical Engineer ss. Steam Engineer ‘ lane Mechanie eovees Shep Superintendent pentieees ry Publte Ac Building Contractor we, ey Sakae cum acnged Structural Engineer eves ANIL ry ie ineer exceed Mechanical Engineer oe wore gineer Name 5 DIAMONDS WATCHES oNCREDIT Our Great Special! ; Loftis Perfection Diamond Ring The Most Popular Solitaire Dia- fo mond Ring. Each Diamondis specially selected by our dia- mond experts, and is skilful- ly mounted in our famous _ Cased in Handsome Ring Box“ Loftis “Perfection” 14k solid gold 6-prong ring, possessing every line of delicate grace and beauty. A pobre eo Diamond is the best woman into which put your money, it constantly increases in valve | and lasts forever. Every article listed in our Catalog is distinctive in richness and elegance, no matter what the price. Send for Free Catalog There are over 2,000 illustrations of Diamonds Sewers. ete, Whatever you select will be sent. ae ches, charges id. You SEE AND EXAI E THE CLE Ri * IN YOUR OWN HANDS. If satis- fe pay one-fifth of purchase price and keep it, bal- ance divided into eight equal amounts. is, payble's ery i SPECIAL OFFER! ,. 22. WATCHES 26. That Will Pass Railroad inspection — ONLY $3.00 A MONTH Our Catalog illustrates and describes all the new watches —15, 17, 19, 21, 23 Jewels, adjusted to temperature, isoch- ronism’and positions. All sizes for men and women. Your choice of the popular fashionable designs, Guaranteed = the be wore to be accurate timepieces, in perfect run- and further guaranteed by us, [OF TIS = sess BROS&CO.fss8 «STORES Im LEADING CITIES HE . PEST WAY T 10 ¢ GO Sa oe thousands. ) Torkenn's steponaner aaa 1) of the rides saved. “A out- tam | ead's FACTORY TORMDER \ Eales ian Sivas Dee 0 latest war ap) 30 Days Free T: broken.—EDWARD H. CRUSSELL. 108 | By Poe Se ee ~

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CARP ENTRY CONTRACTING 5 volumes, each 514 x 84 inches; bound in erican Morocco; flexible, handy style; 2138 pages and more than 400 illustrations, plans, blue prints and diagrams. This 5-volume Cyclopedia of Carpentry and Contracting is the very latest—most complete—most practical work of its kind ever published. It covers s everything you need to know about y and the t it explains every prob- on great or small—every modern approved method gathered from hundreds of different sources. The combined work of 25 well known men, each an expert in his own particular field, is what this cyclopedia gives you. Every detail of ae is discussed ate renngh from. the beginning of the plans to i b the large, vl ag fire-proof a liga No man engaged as a carpenter or interested in the buildin® and contracting business can afford to do without these books- create a new earning power in you and in évery man from the carpenter's helper to the head of the business. Every e you a world of valuable information that you could get with years of experience before. Besides this, a year’s consulting service in the American Technical Society is yours FREE. r-— This Is Only a Part of — What. the Books Contain Carpentry (including everything from the raw tim- ber and tools to the trimming and turning over to the —Steel Square—Plastering and ting—Mechanical Drawing—Blue Print R Architectural Drawing—Sheet Metal Work—Building Superintendence—Underwriters’ Requirements—Heat- ing and Ventilating—Steam and Hot Water Fitting— Sanitary Appliances—Water Supply—Drainage and Venting—Domestic Hot Water Supply—Hardware— and S Legal Re- lations—Building Code—General ~egen and Review Questions and Index to each volum:

Lag

Ask all the questions you want for a whole year. service is absolutely FREE. SHIPPED FREE! DON’T SEND ANY MONEY Don’t take our word for it ee ae rane pon (with the * me lines filled

the small express costs and use them as if they were your ior Then if you think you want to get along without the advancement they will bring you, send them back at our ex- them send us $2.00-as first pay- r price is $25.00 AMERICAN TECHNICAL SOCIETY Dept. CC1201 Chicago, U.S. A. r. SE SSS NE NR RO NO ERNE ES = American Technical Society, Dept. CC1201, Chicago. Please send me the 5-volume gaa of Carpentry and , shipping collect. I will send you $2 al POOREST OHE ETE EH HEHE EEO DESEO RES SEES peace’ DAS Soy OP ty epee ee oe ee ¢ (ReRe le TS AN LN MR NOR NS ET

Popular Science Monthly A Baseball Batting-Machine The baseball fan may still exercise himself with the bat when winter chills compel him to stay inside By A. D. Goodrich T a summer camp of an athletic club there was no suitable field for playing baseball, and some of the boys manufactured a_ batting-ma- chine. With its help they could play their ball games on a small lot back of the camp or in the gymnasium on rainy days. Any number could play; they seemed to get about as much sport out of it as in playing the regu- lation game, and the machine was in almost constant use. Such a machine can be used in the winter for indoor exercise. The materials for this batting-ma- ehine are easily obtainable at a reason- able cost, and any boy with a little knack in using the most common car- penter tools can make one in a few hours. The upright or score-board of the machine is made of good clear pine planed on one side, 12 or 14 ft. long, 4 in. wide, and % in. thick, supported by a base with braces, as shown in Fig. 1. The base framework should be about 3 ft. square, with the bottom boarded over to strengthen it, and stones or bags of sand laid on it to weight it down and steady it. At the top a 6-in. strip is nailed to the back of the up- right, as shown at A, Fig. 4. This strengthens the projecting piece B, to which is fastened a small pulley, C, that carries the line D. The line or cable should be strong, fairly heavy, but easy running cord—a good trolling fish-line is about right.

dBase hit->-3— Foul ball

-|— Sw | Strike

Fig.2 Details of the standard and ball for strik- ing and base for holding it firm to the floor 104 The weight at the lower end may be either an iron bolt or a piece of lead cut or molded to a pear-shape, and, when fastened to a line that is fully un- wound, hangs about 2 ft. from the ground. He is striking the ball to make it record hits on the marked upright The bell may be one from an old alarm-clock or the top of an old bicy- cle bell. This is fastened to the face of the score-board H# near the top, the stem coming at one side of the line, which must pass freely under the bell. First, the bracket extending from the standard and supporting the striking arm is made. The horizontal boards are about 4 in. wide and 22 in. long, fastened 42 in. from the ground to the standard with a reinforcing piece of board at the back and a similar piece connecting their forward ends. Two braces run diagonally up to the stan- dard and are nailed to it. The striking arm is a piece of wood 18 in. long, 314 in. wide, and 14 in. thick. Beginning a short way from either center, its ends taper so that the last 2 in. of their length may be whit- tled round to go into the holes bored in two croquet balls. The balls may be held in a vise for boring the holes, and the holes should be a drive fit for the tapered stick. Glue should be applied before driving them in place. One of these balls serves as a striking ball, and is shown at G, Fig. 3. The ball G is padded by placing strips’ of cloth or cotton batting around it and winding the whole with twine. The striking arm shaft J is merely a 2-in. square of hard wood long enough to reach through the bracket boards ican A a SEEN SP ROP ENE

qj —- bbe ut me wee a hal Ua Oe

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A an ne ee WO gl ad nahn pce E SI oe January, 1919 and afford a projection at either end, as shown. This projection should be of sufficient length at the striking arm end to permit the balls to rotate with- out striking the bracket board. At the other end it is long enough to place an iron washer over it and to drive a wire nail through the shaft to hold it in its bearings. The head of this nail should be removed. Of course, that part of the shaft passing through the bracket boards and within them is made round, and the holes in the boards are bored large enough to permit the shaft to rotate freely but not loosely. These bearings should be kept well greased. The shaft engages the striking arm by a square hold cut through the center. A nail driven into the shaft from the edge of the striking arm secures these parts. The cable end is tacked to the shaft at one side, and so wound that it will wind up when the striking ball is hit. This ball, if it does not adjust itself, must always be turned straight down- ward before it is batted again. Any number of players, equally divided to represent sides, can play the game. captains to see who will have the choice of ins or outs; the outs stand aside until three men of the ins have retired themselves, as in the regular game; then the outs take their turn at the bat. It is well to have the bases marked out near the machine and the players take their places as the score is shown on the board at each hit: that is, if . the man at the bat hits so that the marker goes to 2-base hit (Fig. 2) he at once takes his position on second base; if the next man makes a 2-base hit he takes his place on second base, and the first man steps home and scores a run; and so on through the game. In other words, the game is played exactly the same as the regu- lation game, except that the machine is used to take the place of the pitcher and catcher, and as soon as the boys get used to hitting and scoring with the machine plenty of sport and also beneficial exercise will be the result.—A. D. GOODRICH. An Eye-Bolt Made of a Piece of Sheet Metal N EYE-BOLT being needed in the construction of a small boat far from any place where one could be purchased, the workman made one from a piece of metal, as jo i ie) shown. ol re) A strip of sheet metal was ue bent double in fl bi The metal bent to the exact cen- substitute an eye-bolt = ter, and the ends again bent at right angles to the double shank left by the first bending. A hole of suffi- cient size was then drilled in the ends for screws.—L. B. ROBINS. A toss is made between the two - BePopular! MakeMoney! Learn MUSIC at Home! HY envy money through the your FREE LESSONS. musical talents they de- friends IN veloped by our Home their knowledge | Piano Trombone | / raining Method. of how to play | Organ _— Flute Our free book tells the piano, or- | Violin Clarinet. | you all about it. Read gan, violin, cor- — ace the letters in it, and net, or any other Banjo Sight you will see that what musical instru- | Mandolin Singing others havedone easily, ment? Harp Harmony | you can also do easily. Be talented | Cello Saxophone | More than 200,00omen, yourself. Make women and children friends. Make money. havelearned byour system. Best Teach your children. You yourself can mas- ter any musical art right in your own home with the greatest ease. We have taught thou- sands how to play their favorite musical instruments easily, quickly and thoroughly without a teacher just by following our New Improved Home Study ‘Method. Wedoawaywith the private teacher. We banish dry, tiresome exercises: We teach you by note. No num- bers; no tricks; a sound musical education. We make it as fas- cinating for you to: learn, as it will be fascinating for you to show your friends what a good musician you are. Our pupils are in demand as entertainers, and some of them have written to us that they aré making 105 ‘ of all—we give you all lessons free. Write at once for particulars. MUSIC LESSONS FREE =—ACT NOW Just mail the coupon. Because we need one pupil in each locality at once to help us advertise our marvelously easy system of teaching music, we offer for a limited time our lessons without cost, and charge you only for postage and sheet music, a small sum weekly. A musical education in any instrument for the price of a movie ticket each week? Beginners or advanced pupils. This offer is too important to hesi- - tate over. Get the proofs, facts, letters from our pupils. Get our fascinating, new book just is- ¥ sued, together with our as- tounding offer. All of these 7 come to you-FREE. Just drop us a postal or mail U.S. the coupon today. we np gd U S SCHOOL 7 81 Brunswick Me. iy 4 Bidg., New York OF MUSIC pore i ° send me your free k, 81 Brunswick “Music Lessons in ‘Your Building 7 Own Home,” and particu- New York, lars of your offer of free lessons in any musical instrument... ee ee ee | ee er

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era aa qn N uo Wi} as : we : i i MT : D ADVE : i ms es Rate 20 Cente a Word, payable in agraace. | 10% Discount — Six Insertions. ee TIs I N iG 3 ISINERS sity February issue closes December 20th

ik RESIN AND ACCESSORIES

ER—I clea’ bom, Saves casting, aan repat ana Beas este Fits all cars. Fords do 34 miles to gallo ona ue pares. for free livera PE gy Man ufscturing Company, panei Ln ino ane cle at small cost b — Shaw Mo ‘Motor Attachment. Catalog. free free. Shaw Mig. Co Co., Dept. 180, Galesburg, Kansas.

PATENTS for automobiles are in great demand. We have special Auto: m deman' rite Illustrated a gen — “How to Obtain A Patent.” Vic- tor “3 J, Evans & Co., 172 Ninth, Washington, District. of

BATTERY Charging pays big profits. WAS currents os gas engine operates. Easy terms. Hoberts, Troy, Ohio. INSYDE Tyres, inner armour for Automobile Tires prevent punctures and double mileage of any tire. Liberal fits. Details free. American Accessories Co., Dept. 7-A, Cincinnati, Ohio. TIRES—Double Tread Guarantee for r good ee chage Ab- ag 30x3 (37.00; Saxa, $10. 310-00; 3404 fet 02 Baus. Sis-O0: S735, § Big saving on other sizes ani tubes also. Trade in your Discount to eles 10% =p! required ome. O.D.orders. Send for list ea State size and bead of tire. . Max Liben & Co., 205P Wes 48th Street, New York. TIRES At Wholesale—Send For Prices on guaranteed tires and tubes. Lowest prices on earth. Overton Tire Co., Box P, Pp ociwin, Iowa. “GAS-SOL” gives. you 15 to 40% more mileage and eliminates carbon. oney back Guarantee. 100 tablets treat one hundred golions gasoline. Price One Dollar. Live agents wanted. Gas-Sol, Dept. B, Wakefield, Mass. MORE a. less fuel, no carbon. No mystery, plain on. results guaranteed. Write for booklet. No-Leak-O m Ring Company, Baltimore, Maryland. ee auto-tires is now a growing and pe pret able KS ee eos May a amen. aoe , Plants $300. ee. quipment Company, 302 8th Street, Cincinnati, Ohio. . TIRES ¥% less. Buy direct at manufacturer’s price. Guaranteed 6000 miles. Shipped prepaid on approval. Motorist apenas wanted. Write today. Give size of tires. = ar A & Tire Co. , 842 Grand Avenue, Kansas City,

AUTO Motors and Supplies. Buick—Hupp—Franklin— ee ee oe water and air cooled Motors $30.00 each and oe. Bosch Magnetos—$10.00 each and up —Presto Tan = S. 00—C oils $3.00—Carburetors $5.00— Lamps $4.40—Spot Lights $3.40—Motor Horns $2.85, Air Compressors, etc. Write for Bargain List second hand auto accessories. Johnston, West End, Pittsburgh, Pennsylvania. WILL purchase good automobile accessory, or handle same on doe basis. F. R. Company, Box 67, Station B. Cleveland, Qhi: é MR. ADVERTISER: If you knew as much about the pulling-power of Popular Science Monthly: as the ad- vertisers re ted in its columns, your advertisement

teresting information about this department. =, we? D. W. Coutlee, 225 West 39th Street, New York City

FORD ACCESSORIES

FORDS er? Wasy in Cold Weather with our new 1919 uretors. 34 miles per gallon. Use cheapest gasoline or half lg Incr power. Styles for any motor. = slow on high. Attach it yourself. Big profits to ents. Money > Be gtr 30 days’ trial. Air- Friction Carburetor Co Madison, Dayton, Ohio. DEALERS: A it’s for a “Ford” car we have it. Write for price list. niversal Motor Supply Company, White Plains, New York DEMOUNTABLE Outfits complete, $12.50. _De- mountable sets, 55.50. Good agents’ proposition. Kable, West End, Pittsburg SUNLIGHT for Pan Bright light all speeds, with dimmer, $2. aran 100° Profit for agents. Sun- _, ave mpany, 1508 Lytton Building, Chicago,

SPECIAL — on Ford Tires: 30x3, $10.50, tube, $2.25; 30x34, $12.50—tube, $2.50. * John A. Martin, Aber- deen, South Dakota.

ELECTRICAL MAKE Dry Batteries. Simple, practical instructions a blue print, 25 cents. Dirigo Sales Company, Bath,

INVENTORS. Send sketch and description of your in- vention for advice regarding patent ns egy og a mnie Machine Works, 1911 North 12th Street, it. Louis, Missouri

FORMULAS & TRADE SECRETS

~FORMULAS—All kinds—Valuable CG “Bestovall,””. Box 543-PS., Chicag es cece erat rt furnish a rpaaien caarantesd Formula or Trade Secret for any purpose for only 25c. State exact requirements enclosing coin. Raymond, 1354S Central,

106 FLAGS

FLAGS: 3x5 feet fast color American flag, $1.00. Also larger sizes. Allied and ‘‘Welcome — flags, all sizes. Jensen, 342 W. 42., New York City “TWENTIETH CENTTRY BOOK OF RECTPES, FORMULAS AND PROCESSES’’—This book gives you the information that represerits the collection of years and the expenditure of thousands of dollars. Contains complete directions of making everything from simple glues ond. ad- hesive to the tanning of leather, the making of Photographic materials, oe soaps, plating of silver and gold, work- i f metals. 9 ‘Deena. a eaected Snbiects. epartmen opular Scien 225 West Thirty-ninth Street, New York. cue eaands

te meneame rsare

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“peso 0 RN RRR ENB EE TN cet January, 1919 When Shooting HERE is a great deal of contention among shooters as to whether it is better to shoot with one eye closed or both eyes open. The diagram will prove that it is best to shoot with both eyes. open, since, in using one eye, there is somewhere in the range of vision a blind spot. Hold the diagram at arm’s length, close one eye, look steadily at the cross, then slowly draw the page toward your face. A position can be easily found where the bird in the picture will vanish. Open the closed eye and the bird will be clearly seen as before. Everybody has a blind spot, and that may be where the aim should be This shows not only that there is a blind spot when one eye is used, but that the blind spot for both does not coincide. Therefore both eyes should be used in shooting, so that the whole range of vision will be clear and distinct. Suppose that you are about to shoot at a bird thirty yards away, and shut one eye; you are blind covering a space of several feet. Ifthe bird flies through that blind spot he will fool you every time. Clay bird breakers and game hunters are learning to shoot with both eyes open to get the maximum efficiency for aecurate shooting. Because a moving target has to be led with the gun muzzle, it is a mighty easy thing for the wing shooter to lose his bird because the lead placed his target in his blind spot.—F. E. BRIMMER. Grinding Broken Hacksaw Teeth to Prevent Slipping ACKSAW blades that have a few teeth broken out may be re- stored to usefulness without stripping the remaining teeth, by grinding the top off the adjacent on each side of the broken section, and grinding three or four teeth on a slant extending from the bottom of the broken ones to the top of the ones that are whole. In grinding saws for special purposes, blades without any set are sometimes required. These may be made from stock blades by resting them flat on the emery-wheel and grinding the teeth down to the level of the body. Many workmen put the blade in the frame for such work, but this increases the breakage. The blade should be taken out of the frame and held in the hand, so that it is more or less self- adjusting. Strained in a frame as for sawing, the tension is such that the jar oftheemery grains striking it breaks the blade just as if a hammer had struck it. Why You Should Use Both Eyes PRINTING, ENGRAVING, MULTIGRAPHING STAMPS AND. COINS GOOD Printing at low prices; 1,000 good letterheads, envelopes, cards, billheads, labels, circulars, $2.50; samples free; catalogués, booklets and circulars our specialty. Ernest L. Fantus Co. 523 8S. Dearborn St., Chicago, Ill. 100 CARDS, Business, Professional or Social, also imita- tion leather card case, for 60 cents. M.-F. Devaney, Print- ing, Fagraving, Rubber Stamps, 31 Middle Street, Geneva, ew York, 125 Letterheads, envelopes, billheads, tags, or cards, 75¢ postpaid. Printer-Laborde, Mansura, Louisiana. 100 Bond Noteheads, 4 lines, and 100 envelopes, prepaid $1.00. Southwestern, 1413-B Berendo, Los Angeles. ' 208 Genuine - Foreign ‘Stamps—Mexico War |. Issue, Venezuela, Salvador and India Service, Guatemala, China, etc., only 10¢. Finest Approval Sheets 60% to 80%. Agents Wanted. Big 72-page Lists Free! We Buy Sta . Est. 25 mao E. Hussman Stamp Co., Dept. 55, St. FREE, 25 different United States with 60% approvals. Enclose 3c. 106 different United S *seldenberg Beecher, Illinois. asia Bi START Your Own Stamp Business! Our trade tn Africa, Borneo, China, Philippines brings thousands rare stamps. Make Big Money selling them. Send 50c for sample stock. Calculator Corporation, Grand Rapids, Michigan. * ACTUAL Typewritten Letters, heading black, body purple 100, $1.15; 500, $2.00; 1000, $3.25; 5000, $12.00. Artes Letter Shop, 409 Chestnut Street, Milwaukee, Wis- consin. OLD Coins. Targe Fall Selling Catalogue of coins for sale free... Catalogue quoting Sew paid: for coins, ten cents. William Hesslein, 101 mont Street, Dept. P, Boston, Massachusetts. NEW large catalog of attractive Gummed Labels and advertising stickers free. Royal Label Company, 414 Cherry, Philadelphia. MR. ADVERTISER: If you knew as much about the pulling-power of Popular Science Monthly as the ad- vertisers represented in its columns, your advertisement would be in this snace. We will be glad to give you some in- teresting information about this department. May we? D. W. Coutlee, 225 West 39th Street, New York City. AUTHORS—MANUSCRIPTS WRITERS: Stories, poems, plays, etc., are wanted for publication. Literary Bureau, 117. Hannibal, Missouri. WRITE for newspapers and magazines. Big Pay. Ex- pertanve unnecessary; details free. Press Reporting Syndicate, 400, St. Louis. MANUSCRIPTS typed, lowest rates. Editorial criticism and revision. Our booklet aids ambitious writers. Mailed free. Story-Craft, Washington, D. C EDUCATIONAL AND INSTRUCTION FREE, 60 different stamps including Newfoundland, China, Japan, Mexico, etc., to applicants for our high grade approvals. Send 3c stamp for return postage. The “dgewood Stamp Company, Dept. M., Milford, Conn. STAMPS. 61 All Different, 3 cents. Mention paper. Quaker Stamp Co., Toledo, Ohio. $2 to $600 id for hundreds of old coins dated before 1895. Send 10 cents at once for new illustrated coin value book. Size4x7. It may mean your fortune. Clarke & Co., Coin Dealers, Box 76 LeRoy, N.. Y. PACKET “A” 100 varieties foreign stamps, 20c. F. J. Pope, Charlotte, Vermont. “se hi 17 Varieties Hayti Stamps 20c. List of 7000 varieties, low riced stamps free. Chambers Stamp Co., 111C, Nassau t., New York City. : CALIFORNIA — quarter size, 27c; half-dollar size, 53¢; dollar size, $1.10.- Large cent, 1818, and catalogue, 10c. Norman Shultz, King City, Missouri. STAMPS, 50 Varieties, Transvaal, Brazil, Peru, Cuba, Mexico, ete,, and Album, 10c. 1,000 mixed, 40c. 60 dif- 5., 200:;, 1 hinges, 10c. List ‘free. on wv. Oo" ee ,000 v7 I buy stamps. 5 i ; . onal tegman, 5949 Cote Brilliante, St. Louis, WANTED—New Ideas. Write for list of Patent Buyers and Inventions Wanted. $1,000,000 in prizes offered for inventions. Our four Books sent free upon re- quest. Victor J. Evans & Co., 178 Ninth, Washington,D.C. MOTION PICTURES FREE TO Writers—a wonderful little book of money- making hints, suggestions, ideas; the A B C of successful story and play-writing. Absolutely Free. Just address: Writer's Service, Dept. 6, Auburn, N. Y. WRITE Photoplays: $50 each. Experience unnecessary; details free to beginners. Producers’ League, 194, St. Louis. ELECTRIC Arc Generator halves expense. Your engine operates. Easy terms. Hoberts, Troy, Ohio. PHOTOPLAYS Wanted. Big prices paid. You can ‘write them. We show you how. Free particulars. Rex Publishers, Box 175, F 9, Chicago. PHONOGRAPHS AND SUPPLIES BUILD your Phonograph. ‘‘Perfection’’ high quality spring and electric Motors, Tone Arms, Reproducers. Wonderful results. Big saving. New catalog and building instructions mailed for ten cents. Indiana Phonograph Supply Co., Indianapolis, Indiana. / PHONOGRAPH Owners: Test our wonderful, new Ring Point needles. Buy at wholesale prices and make money selling to your friends who hear how they improve tone. Scientific method, important discovery, very intercsting. Single needle plays 100 records. Send 25c for samples and = offer. B. Kenyon Company, 31 Union Square, New ork. CAMERAS, PHOTOGRAPHY, SUPPLIES MAIL us 15c with any size Film for development and 6 velvet prints. Or send 6 negatives ony size and 15c for 6 prints. 8 x 10 mounted enlargements 35c. Prompt, perfect service. Roanoke Photo Finishing Co., 212 Bell Avenue, Roanoke, Virginia. NEW Book—Just off Press—Free! ;The title is ‘‘Sensa- tional Money-Saving Bargains.” Shows scores upon scores of sure ways to cut a big slice off the price of all kinds of Cameras, Lenses, Kodaks, Supplies and Acces- sories. Get a copy. It will open your eyes—make it im- possible for anyone to fool you with high prices. Write us today. David Stern Company, 138 Davsco Building, 1027-29 Madison Street, Chicago, U. 8. A. KODAKERS: How would you like to get a 9x11 en- largement of your best negatives Free? Drop us a card now asking about it. Films developed 10c per roll. Prints 3, 4 & 5c each. Fords Foto Studio, Ellensburg, Washington. MUSIC AND SHEET MUSIC OLD Coins wanted. 24-page buying catalog, 5 cents. A. Kraus, 237 Kraus Building, Milwaukee, Wisconsin. STAMPS—125 foreign—3c; 350 different—30c. A pores 50%. Benjamin Forbes, 160 Devilliers, Pittsburg ennsylvania. : STAMPS! 50 different Belgium (large bi-color) China, Jamaica, Portugal, Venezuela, etc., 10c; 1,000 well mix ; 100 various U. S., 50c; 1, hinges, 10c; Agents ted; 50%. List free. I buy stamps. L. B. Dover, wan Overland, Missouri. 105, China, etc., Stamp Dictio , list 2c. Album, 500 illustrations, 3c. Bullard, Station , Boston. “SPECIAL” packet 10c. Rare stamps on a val. Sears-Nelson, Oak Park, Illinois. wi = STAMPS—12 different from warring nations, 10c; 10 different foreign coins, 15c; 10 Uruguay stamps for 16c. Lists free. Toledo Stamp Co., Toledo, Ohio. FREE: 25 different United States Stamps to approval applicants. Postage3c. Jukes, 4220 Walnut’ Philadelphia. COLLECTION-FILLERS—200 varieties good stamps at 35¢e; 65 cent. approvals; ‘‘OK” Packet at 15c or 4 for 50c. Red-Jacket Stamp ompany, Penn Yan, New York. FOR SALE OR EXCHANGE CHOICE Silver Black bi f . Bothwell, Ontario, Canada. reeding foxes. Reid Brothers, REAL ESTATE—FARM LANDS CALIFORNIA little farms, near Los Angeles, for sale. Easy payments. Write E. R. Waite, Shawnee, Oklahoma. THE Real Estate Educator—A Book for hustling real estate boosters, promoters, town builders and every man who owns, sells, rents or leases estate. Covers fully Workmen's Compensation Act, Income Tax Law, Employ- er’s Liability Act, Statute of Frauds, How to Sell Estate, How to Become a Notary Public or Commissioner of Deeds, “Pointers,” ‘Don'ts’. and other information. 256 Pages, Cloth, Price, $1.50. Book De ment, Popular Science Monthly, 225 West 39th Street, New York. MONEY-MAKING Farms—l17 States—$10 to $200 —. fon ae = —— bene anager = to settle quickly. Ta ca e. Strout Farm Agen Dept. 12, New York. a: aoa my ~ GAMES AND ENTERTAINMENT NEW Patriotic Plays, Recitations, Entertai war-time Benefits. Vaudeville Sketches, iaoneon — Drills, Tableaux, Make-Up Goods. Catalog T. S. Denison & Co., Dept. 26, Chicago. TRICKS and Greenbacks. B ——— greenbacks—10c. Gil ico, magic catal 1115 So. , .: SONG Writers: Submit your song-poems now for free examination and advice. Valuable booklet explaining our original methods of revising, composing, copyrighting and facilitating free publication or outright sale of songs, Sent Learn the truth from a reliable Free on tal uest. Mine nicker- successful concern. Satisfaction guaranteed. bocker Studios, 168 Gaiety Building, New York. WRITE the Words for a Song. We write music, guar- antee publisher’s acceptance. Submit poems on patriotism, love or any subject, Chester Music Co., 538 South Dearborn Street, Suite 111, Chicago. ; WRITE a Song—on any subject. I compose music and guarantee publication. Send words today. Thomas Merlin, 238 Reaper Block, Chicago. WRITE the Words for a Song. We compose music, secure copyright and submit copies to leading publishers. Submit poems now—examination free. Broadway Studios, 121C Fitzgerald Bidg., New York. LITERARY SPEECHES, essays, distinctive advertising letters, pamphlets, and special articles prepared for all occasions. words $1.50. Gertrude Sanborn, 778 Farwell Avenue, Milwaukee, Wisconsin. DIAMONDS, WATCHES, JEWELRY FREE—Scientific Gem. Rivals diamond. Clear white, brilliant, flashing, deceives experts. Free examination. Write for booklet today. Harold Lachman Co., Dep't. 9201, 12 North Michigan Avenue, Chicago. 107 1,000 stage tricks with 500 illustrations. Catal 10. small catalogue FREE. Hornmapn Magic Co., Sta. 17, 470 Eighth Avenue, New York. TRICKS, Puzzles, Jokes, Toys, Games, Novelties, Dolls and Cane Racks, Plays, Wigs, Stage Supplies, zocanse and Tilusions. Large 1918 Catalog Free. M: Com- pany, Dept. 535, Oshkosh, Wisconsin. PORTEMANTEAU Theatres constructed. Scenery for hire. Catalog. Amélia Grain, Philadelphia. SEND 10c for two issues of our interesting containing 55 valuable Formulas, Tricks, ng 4 hold Hints. Globe, Sta. “C,” Box 7, Montreal, Canada. PICTURES AND POSTCARDS JOIN Live Postcard Club. Membership Papers 10c. Harvey Teeple, Decatur, Indiana. DO You Like Pictures? If so, your name please. O. W. Miller, 105 Chambers Street, New York. Lg Alt = pictures 2 dens, club- rooms, . Send dime for generous sample, lists, prices, ete.. If you want pictures worth Se are sure to please. Jorst, Box 253, Saginaw, STAMMERING STAMMERING cared—quickly, permanently. and rivately. Write me personally for Free Copy of new book, Pow to Sto E. Robbins, Prin. Boston Oy ae clammercs’Toattuen 2 Muntaeton Avenue Besta Massachusetts. | | | | | pai ota ek

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‘Expert FOR INVENTORS

Mov also tions and 600 Mechanical Movements, om Ts ne pert advice and Truth abort Patents “ges re of Kelly, 912A Woodward Building, Washington, D.

an thane Your Tavention. you must get in touch with per _nersons. Coutloe 298 Warr aaets iat ten ee PATENTS, Trade-Marks, and © Secured. an E pptind sent * foanest moins Bann Weshinaten noe A second ational Bank

PATENTS. Rooklet free. Hizhest ces. Rest re- sits. Promntness sssured. tson man Lawyer, 624 F treet’ Washington D. Ge Patent

AGENTS: “New invention piz7les world; wond-rful chemical «loth; one rub over rain, snow blurred auto wind- shieli; street- -c_T or engine w: ndow, presto! glass stays clear 24 hours; can’t blur; agents m king $120 wcekly. Security Mfg. Co., Dept. 56, Toledo, Ohio. OUR New Inventions earn you steady income. Can- vassers, County Rights, Salesmen and Promoters write adam Fisher Mfg. Co., 183G, St. Louis, Missouri. AGENTS: _Big money selling aot household invention. Sample 25c. Particulars nage Webster & Company, 2935 North Clark Street, Chicag: $10 DAILY refinishing er brass beds, automo- biles, by new method; producing amazing results; no capital or experience necessary. Particu free. Gunmetal Co,, Avenue F., Decatur, Illinois. AGENTS—$a0 to $100 a week. Free samples. yc and silver sign letters for stores and office windows. An one can put on. Liberal offer to general agents. Metalile Letter Co., 400 N. Clark, Chicago. AGENTS—Make $5.00 to $20.00 a day selling guaran- teed silk hosiery and underwear direct from factory to wearer. Live agents wanted everywhere. Write today. Cc. & D. Company, Dept. 10, Grand Rapids, Michigan. “WERE You Ever Offered a Grocery Store? Our Pro = tion Is Better. Tet us tell you how you can handle Flou Canned Goods, Provisions, and entire line of groceries well as Paints, Roofing. Stock Foods, Automobile and Machinery Oils and Greases. No rent to pay. No invest- ment in stock. Large orders taken from samples. Goods of guaranteed and proven quality., Selling eg not ¢ for ‘workers.’ ary. Very profitable work 220, Chicago, iilinois,

neress Fiteheock Hill Company, Dept. , Reference: ;_Anv bank or express company.

INSYDE Tyres, inner armour for Automobile Naa prevent punctures and double mileage of any tire. Libe profits. Details -free. American Accessories Co., Dept. 97, Cincinnati, Ohio. ; MAKE and Sell Yonr Own Goods. Machinery unneces- sary. Exnert Chemists advise. Special attention to be- ginners. ‘Write for Formula Catalog. Elmer Mystic Com- ma eee me om

Sample Ie 25¢. Seescepilt 307 McFerran oe Teereinnta: PATE Write for Free Miustrated Guide Book. Send sketch. or model for’ free opinion of its patentable nature. Highest References. Prompt Attention.. Reason- able Terms. VictorJ. Evans & Co., 174 Ninth, Washington, District of Columbia. KEROSENE Burners for Furnaces, Cook and Heating Steves. Economy Mfg. Company, 616 .West Monroe,

Popular Science Monthly A Screw-Driver with Two Angle Blades. NE of the most handy screw- drivers to have in one’s tool-box is the angle blade, which has three edges. To make it, draw out the point

The three edges of this screw-driver blade make it adaptable for any kind of work quite wide, and grind the edges at an angle of 25 deg. to the center line of the screw-driver. When the side edges are used, the length of the screw-driver makes a leverage for starting or turning tight or close fitting serews.—EDWIN M. Davis. Weighing Large Articles in Instalments OMETIMES one desires to weigh an article too heavy for the scale at hand, or too long to rest on the plat- form. In such cases, it is possible to resort to the trick of weighing first one end of the article and then the other. In the illustration the entire weight of the shaft C is supported at the two points A and B, and if there were two scales, one under each point, the com- bined amounts would equal the total weight of the shaft. With one scale the same result can be obtained by weighing first one and then the other and adding together the two amounts. To obtain the greatest accuracy, it is necessary that the shaft rest on the two A-shaped supports. The one not on the scale should be blocked up on a level with the scale platform D. A chalk mark should be made on each

PULLEY pei? a c [paeigigy?: _ -- ——-~—~ ~ il B wooD BLOCK. Supporting an article so that it can be weighed one end at a time end of the shaft where it takes a bear- ing. One end should be weighed, and the amount recorded. The shaft should then be turned end for end, and placed so that the chalk marks correspond with the bearings. The second weighing should be added to the first, and the total will be the cor- rect weight of the article. A freight-car may be weighed on a scale that is too short or too light by weighing first one set of trucks and

Chicago. 108 then the other.—W. H. SARGENT.

ae aS ee Oe

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January, 1919 Removing a Pin from a Ford Clutch. O replace a broken Ford clutch- spring or clutch-spring support while the engine is in the chassis is a difficult task, unless some good means of compressing the clutch-spring is used. This can be accomplished with the use of an old hub-sleeve from a wagon wheel or a piece of pipe about 214 in. in diameter and 1 ft. long, anda piece of board 4 ft. long. To replace the spring, remove the drive-shaft and cover-plate from the transmission- case. Turn the engine over until the taper-pin hole in the transmission- shaft comes in line with the opening of the transmission-case. Place the clutch-spring, clutch-spring support, and collar over the end of the trans- mission-shaft. Place the hub-sleeve or piece of pipe against the clutch-spring support, al- lowing the collar to be free, as this will afterwards permit one to line up the taper-pin holes properly in both trans- mission-shaft and collar. Bore a hole in one end of the board about % in. SEAT: JACK = ply the big demand for finger print experts in banks, big factories, detective agencies, etc. Special limited offer—write while it lasts. University of Asus Science, Room 9201, 1810 Wilson Avenue, Chicago, Illinois. THOUSANDS Government Jobs open to men—women —girls. $95.00 Month. Quick. increase. Short hours. Common education sufficient. Write immediately for free list of positions open. Franklin Institute. Dept. Y50, Rochester, New York. GET a government ition through us. Position or money back guaranty. housands of men and women, 16 to 60, needed in Washington and elsewhere for the years of “reconstruction” ahead. We'll coach you quickly by mail for Civil Service examination and appointment. Perma- = easy hours;-paid vacations; higher salaries. Our free KRG" gives ist of positions; Write for it. _—- tom “civ ‘Se Service School, 2027 Marden. Building, Wash- ngton,

Earn $35 to $45 week. Learn, while ing. need Pleasant, interesting work. o Pam ied. Write for free sample lessons. Franklin. Institute, Dept. Y8'

Ten inexperienced men _ divide * MEN—women—siris. Become automobile ee. INVENTORS. Send-sketch and description of your in- vention for advice regarding patent protection. No charge for this service. 20 years yan Prompt personal service. Patents we secure advertised without c in py Mechanics Magazine. Particulars free. Talbert & ae ES Patent Lawyers, 4101 Talbert Building, Wash- nm, D. : DETECTIVES make big money. Beone. Write Amer- ican School of Criminology, Detroit, Michigan.

PATRIOTIC NOVELTIES

“To hell with the Kaiser’’—Right red hot me ne gy showing Bill's experiences there. Americans enthusiastic Pestpaid 10ce. Norman B. Ovri, Hemet, California.

BOOKS AND PERIODICALS

INSTRUCTION Book (for shop use) on Vulcanizing Auto-Tires, $1. Lehr Equipment Company, 368 8th Street, Cincinnati, Ohio USED Books. Bargains. Catal Hignes K-2441 Post. San Francisco. (Books Bought) “

BUSINESS OPPORTUNITIES

ENTER a new business. Earn $3,000 to $6,000 yearly in professional fees making and fitting a foot specialty, openings everywhere with all the trade you can attend to: paver learned by anyone at home in a few weeks, at smali ——_ no further capital required; no goods to buy; jo hunting, soliciting or agency. Address Stephenson Laboratory, 15 Back Bay, Boston, Massachusetts. EXPERT Chemist will furnish pam and Trade Secrets in all lines. Lists free. W. L.“Cummings, Ph. D 217 Standart St., Syracuse, New York. MAKE Die-Castings. Sketch, Sample, Booklet and proposition 12c. R. Byrd, Box 237, Erie, Pennsylvania. Le ae for “newspapers and aaa, Big Pay. Ex- ence unnecessary, details Bondioate, 4005, St. Louis. pine i tlre

WAR humane hospital essentials; wounded sailors— soldiers. Vital labor associate to produce. Hanlon, "Toa Arch, Philadelphia. I MADE $30-a week, easy money, evenings, home. Free patos explains. Send stamp. Al Scott, ‘Cohoes, New

YOUR idea wanted. Patent your invention. I'll help you market it. Send for 4 free books, list of patent buyers, hundreds of ideas wanted, etc. Advice free. atents advertised free. Richard B. Owen, Patent Lawyer, 44 Owen Bidg., + gam Sane D. C., or 2276Z Woolworth Bldg., New York BE a detective. travel. Write City, Mo. DOLLARS Yearly in your backyard. No ginseng, fueinecee dope. Newideas. Investigate. Particulars free. . Metz, 313 East 89th, New York. ise Guinea Pigs for us. We aoa all you raise. Pay better than pouliry. - Contract, ulars, booklet nd to raise free. Cavies Distributing c Co., 3141 Grand Ave. . Kansas City, Missouri. MULTIGRAPH Letters build business. Most econom- ical and effective advertising. Printing. Addressing. Low rates, careful work, service. Multigraph-Peerless Letter Company, 241 Fourth Avenue, New x ork. FREE—3 Months to get acquainted; news and opportunity. The Western Miner, beat w. o7th Ave., Denver, Colorado. BUY and exploit wy inventions. Trade for prop- erty. Form com Peete rights. Adar Fisher Mfg. Co., 183D, St. (tae, Missouri GET our special confidential home agency offer on the Choraleon Phonograph—the bee ee new record player. Plays any standard record. ks just like the $150 and $200 kind. Low wholesale ates to one confidential agent only in each town. No canvassing or soliciting. Our plan tells you how to easily make money without effort. Agents wanted for our ready built phonographs. rite quick. Be first to get this splendid offer, The Choraleon Com- pany, 2201 Monger Building, Elkhart, Indiana.

Excellent opportunity, C. T. Ludwig, 424 Westover bide Kaneas

—START a business. 200 plans, 50c. SalesmanshipyB0c. Income builder, 50c. Set $1.35. 35. Central Company, 599 Ninth Avenue, New York. SILVERING Mirrors—Exclusive Tartaric method opens enormously profitable business. Booklet free. P. Barstow, 514 23rd Street, Oakland, California. WOULD you invest $1000 in a high grade business and be your own boss that will net you $2,500 or more every year? Write President, 416S Wainwright, St. Louis, Mis-

FOR MEN AND WOMEN

WHAT Do You Want to Know?—Information vital to the student, the experimenter, the business man, or any inquirer given by experts. Educational, Scientific, Legal, and Business questions answered. Ask’ us the points you cannot find out anywhere else—w © usually know. No charge if unsuccessful, small fee of $1 if we set you right. Send your questions direct from this ad or write for our complete proposition, free. The Kent } Department AL ambridge, Mass. NDIAN Baskets—Wholesale and retail, Catalogue. Gilham. Highland Springs, California. “SEXUAL eyo ze se Canes, ic, authorita- tive, complete, best satisfi Fred B = Law- rence, Mass. BE a detective. Excellent Conary. peed pay, travel. Write C. T. Ludwig, 424 Westover EBldg., ity, Mo. ae eee our interesting free ~Escket about disorders, bladder troubles, etc. It tells pent a o wml

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Cieniencial Development |: 4% “,@ of Inventions A large and enterprising Engineering Firm are anxious to negotiate with Inventors on an entirely new basis. (x) All Patenting Fees to be borne by ourselves. (2) If we consider the Invention to be of sufficient interest to justify it, we will also bear’the cost of making models and*catryitig out Experiments. G)- Upon completion of\.the patent, the patentee to have-a free hand in _Offering it to any firm or disposing of it as he desires—the only stipu- lation being that, should he dispose of it to any concern other than ourselves, he must refund to us all out-of-pocket expenses. HOUSEHOLD ARTICLES and other Novelties for manufacturing in large quantities after the war are specially desired, and a full description, together with drawings, and, if possible, a model. should be submitted, or a personal. interview will be granted i in London or the Provinces, on communicating with Box 941, SELLS Lid., 168, Fleet Street, London, E.(.4. Mr Edison's ‘Amberoa Free Trial BiIAAE Book Set FREE Join our Success guaran for our free book without delay. N. W. SCHOOL OF TAXIDERMY 1201 Elwood Bide. Omaha, Neb. Books for Mechanics Sheet Metal Work—A manual of practical self-instruction in the art of pattern draft- ing and construction work in light and heavy-gauge metal, including skylights and roofing, cornice work, etc. Cloth, 288 pages, 370 illustrations. Price, $2.00, Postpaid. Machine Shop Work—A comprehensive guide to the most approved methods in modern shop practice, the construction and use of improved tools and machines, hand tools, the lathe and lathe tools, the methods of screw cutting, taper and eccentric turning, etc. Leather, 275 pages, 325 illustrations. Price, $1.50, Postpatd. POPULAR SCIENCE MONTHLY 225 West 39th Street New York City Popular Science Monthh y General Rules er Operating a Heating Plant and Stove Prepared for the Popular Science Monthly by the United States Fuel Administration E sure there is a check draft B damper in the smoke pipe at A besides the turn damper B. This check draft damper is as im- portant in controlling the rate at which the fire burns as is the throttle of an engine. Open it to check the fire and close it to make the fire burn more rapidly. Work it. Experiment with it daily in regulating your fire. The coaling door was not put in the furnace to be used as a check damper. Never open the coaling door to check the fire. If you cannot check the fire without opening the coaling door you need proper dampers. The turn damper should fit the smoke pipe loosely and must never be entirely closed. In the average plant it may be kept partly closed most of nae fo Fi Sea An ordinary type of hot-air heater, showing the location of the dampers the time in mild weather, but during severe weather it usually needs to be opened wide. Use the lift or slide damper in the coaling door at C only to let oxygen in to consume the gases. Have very little draft and let it come from below. Check it by letting more air into the smoke pipe. These are the best general rules. Oxygen furnished from below is necessary for the consumption of the coal gases, and at the same time allows them to be consumed before they are drawn up”. the chimney. This method also keeps coal gas from escaping into the cellar. To make the fire burn more rapidly, do not open the whole ashpit door but the draft damper in the ashpit door. Opening the whole ashpit supplies air to the fire faster than it is needed for combustion. The air is heated, passes out the chimney and thus wastes heat. 110 Wrap all heat pipes in the cellar thoroughly with asbestos‘or a similar covering to prevent loss of radiation. Grates should be cared for properly. A short, quick stroke of the shaker handle will sift the ashes through them. Leave grates in a flat position at all times. Keep the fire pot free from clinkers. Clean ashpit daily to prevent damage to grates. In severe weather shake the grates until a glow appears in the ashpit. In moderate weather a bed of ashes should be carried on top of the grates. Avoid poking and slicing the fire bed. It causes draft holes and clinkers. Never shake a fire that is low until you have put a little fresh coal on and given it time to ignite. A thin fire wastes coal. Disturb the fire as little as possible. Storm windows and storm doors, weather strips and such protective devices are economical of heat. Use them. Keep the temperature of sitting rooms at 68 deg. or less, except when there are old folks, little children or invalids in the family, in which case a higher temperature may be needed. Rooms in which you do not sit are more comfortable if kept cool, 2s a rule, providing the air is kept a little moist. Procure a_ thermometer—a good one. Use it inside—do not hang it outdoors. Keep an even temperature, not more than 68 deg. It is not economical to allow the house temperature to drop way down at night. It takes just twice as much coal to heat it up again next morning. Turn off the heat in unused rooms as far as possible. Bedrooms should be kept much cooler than living rooms. Do not try to heat all the rooms all the time. If you have a hot-water heating system make heavy radiator slip covers and put them over the radiators when not in use. This will prevent them from freezing. Always keep two pans or open top jars of fresh water on radiators or in front of registers to keep the air in the home moist. Study the specific rules applying to the heating system used in your- house. Specific Rules for Hot-Air Furnaces Provide cold air drops from upper floors so as to insure a return circula- tion from all rooms to the air intake of the furnace. Regulate the window _of the cold air box so as to avoid too great a current of outside air; especial- ly on cold days. Always keep the water container in the air jacket filled with clean water. Moist air heats much more readily Se rte the oad ea J 2es a a ee ee ee ee ee ae

Page 107

January, 1919 than dry air and is better for health, as well as for comfort. It is advisable to keep a jar of water near one of the first floor registers, that sends out the most heat. Change the water frequently, preferably every day. Hot air pipes should have a good pitch upward from the furnace and should be of sufficient diameter. They should also be wrapped with sheet asbestos. A separate pipe for each room with turn damper near the furnace is a good rule. Each pipe should be labeled so that certain rooms can be shut off - at the furnace when desired. Specific Rules for Hot-Water Plants Be sure the fire box is gas tight. All cracks must be thoroughly cemented or a new section put in before winter sets in, otherwise coal gas will escape into the airjacket and be carried up directly into the rooms. Study carefully the general rules pertaining to other types of heating plants as well as your own. Notice the clean-out door and remem- ber why it is there. All the water should be emptied

v re = est aaam ee ae

ao @ Cl Ew)

aT] el 7. ay

A steam boiler for house- heating showing the dampers and the automatic control from the plant and clean water put in at least every spring and every autumn. As the water is being heated, use the radiator key to open the air valve of } each radiator in turn until all the air remaining in each radiator is allowed to escape and water starts to come. Radiators filled with air will not heat. Repeat this operation frequently. Always be sure that water shows in the glass gage of the expansion tank which is usually located in the top story of the house above the level of all the radiators. Be sure that the boiler and cellar pipes are covered with asbestos. Study carefully the general rules relating to all types of plants. Keep heating surfaces of the boiler well cleaned.

WARNTED: OFFICE MEN Auditors, Accountants, Office Man- agers, Credit Men, Cashiers, Bookkeep- ers and - Clerks —$1,200 to $7,500. ‘ACTORY MEN Electrical a Mechanical Engineers, Fac- tory Managers, Superintendents, ae Designers, ee 500 to $12,000. STRUCTION MEN Civil and eee Engineers, Transit- men, Construction Superintendents and Foremen, Estimators, egal and Draftsmen — $1,200 to $10,000. TRADES — Machinists and Tool- makers, Auto Repairers, = =~ cians, Stationary Engineers, Firemen, Plumbers, Car- enters, ete.—§ -—$1, 260

uch Job an s Ill. = \ Which one of them could you fill? If you haven’t the knowledge necessary to break into the big-pay class,

All these positions were advertised in a single issue of a Chicago

decid These Q newspaper J Now! ‘Any of the books icra i listed below will quickly fit ten by ex- _ you for a well-paid job—at home perts in plain, —in your spare time. everyday language. They are Carpentry and Fire Prevention

Contr. free from puzzling technical pice wiumey ait ene roo nd Insurance terms. Numerous illustra- more than 400 iustrations. 600 illustrations, diagrams, . 2 Prepares for Contractor, Build- forms, ete. Prepares for Count- . tions, diagrams and tables yoyaiman kegiar Ske Reesat pee make difficult price,$25.00. Special price,$17.80. $20.00. Special price pane. des supple Ci ivil Engineering Electrical Engineering as _ illustrations, os ond 5000" ee. ae photos, tes a are hana” diagrams. Prepares for Civil or . Prepares f for Elec« Otrecteral Bagmeee, ‘Transit- Power Plant ly Seg f in Chiet Diteian cuter ot Superintendent, 8 ian.» Keralar alf or full ce,$45.00. Special price, 80, price,$35.00. Special price,$19.80. leather (ex- Telephony and Accountancy and cept Law Telegraphy Business Management mie 9 Four volumes, 1728 and velumes, 3680 pages ot a 00 illustrations, plates, and sé? Mlustrations, forma which is <ogrems Prepares for Tele- Prepares for Certified Public one Hesinon, Wire Chief, A tant, Audit Offi Ecohen ~) Manage, Trouble anager ecountant, Credit Man or pher, oar Man or m oe Beok Regular Price, $20, WOapecel pecial price,$12.80. price,$50.00. S: price, $24.80, bound in law buckram) and stamped in gold. Fill out One sorabtetien Week Automobile Steam and Gas Five volumes, = —T Seven Bg png Free

Le hpeeny eee eemeee an, Automobi Mechanic or Chauffeur. a fonary, saaine oF 0 or Locomotive bl Regular wale te Oo Special prion SL8N, price, $38.00. Special price $21.80. Trial MachineShopPractice Law and Practice We'll gladly send you any set for seven days’ examination. Don’tsend us a pen: intendent sleeer Mts. Furtecn es just pay the small ship- or Foreman, Foundryman, Pat- trations. Prepares for all Bar charge when the books arrive. tern Mak er, Tool ol Designer or nations, A wonderful ine them carefully—use them ice, aid to business men. $0.00. Seecial trices, £9.80. price. $72.00. Special price ler at your work for an entire week. At Sanitary, Heating and Practical the end of that time, if you feel they Ventilating Engin’ring Accounting aren’t worth far more than we ask, Four volumes, 1454 pages and Four volumes, 1840 pages and Teturn them at — expense, If you keep more pon 1400 illustrations, 800 illustrations, plates and them, pay the perpen price on the easy for Sanitar dis _C, P. A. questions terms explained Engineer, He Heating and Venti- problems, —h ngineer, M Master ter pares fo for cast Gere. Book. American Technical Society Fe eT LO Decale Mee Dent. X1201 Chicago, U. $. A. Se er een ee ee oe aes oe ee oe = ae ae 50c A WE ER 1 American Technical Society, Dest. X1201, Chicago, ill. Yes, if you decide 7 keep the set you - toe 9720. 7 examination, pi harges have selected, send $2 within seven ea a oatisbed. will ssod $2 marlin Till, cxamine ‘ihe days and then $2 a month (50ca we) hmastet spare I th adi on woes, 2300 pages and eee Re: ing Comte

: until the present low price has been ! wil anars os ot your expense. tite wnt ts pase to eae ees 4 paid. Have offer? ever heard of a more rf generous 0 fer? remember, you you ti take : Sane ' ge - sin cida semanas inapleseaied Reco dam ae ee examination ~~ 4 uare notobli om ad them if you a] not care to buy. eed the BAA C88 oases nsec eee coaenne a coupon now—before you turn the page a Reference ..

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me a eee ee Samemea TRADE-MARKS I ATENT COPYRIGHTS Trade-Marks, Foreign Patents, * “Before disclosing an invention, the inventor should write for our. blank form..““EVIDENCE OF CONCEPTION.” This should be signed and Witnessed and returned to us together with model or‘sketch and description of the invention, and we will give our opinion as -to its patentable nature. Our Illustrated Guide Book, HOW TO OBTAIN A PATENT, “sent Free on request. Contains full instructions regarding Patents, Our Methods, Terms, and 100 _ Mechanical Movements illustrated and described, Articles on Patent Practice and Procedure, and Law Points for Inventors. An actual search of the United States Patents made in all cases s before preparing application for: eet. l ; VICTOR J. EVANS & CO, Patent Attorneys | * New York Offices Philadelphia Offices Pittsburgh Offices j ; 1001 Woolworth Bidg. 135 S. Broad Street 514 Empire Bldg. i ,; Main Offices: 760 9th Street, N. W.. WASHINGTON, D. C. i i GENTLEMEN:. Please send me FREE OF CHARGE your FIVE Books as described above. 1 : ME Ce bn Soca cess c'ceWeventscs ESI ps ee a ee Pe | — oe ee eee ee es ee ee ee ee ee ee eee ee eee ee ee ees es ee CAN YOU think of a simple, practical idea that will fill one of the many re- quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed RIGHT Now. Your brains can help. Send to- day for our great new book—“Inven- tions and Trade Marks, Their Protection and Exploitation” and learn more about making » money from ideas than you ever v before. It tells many things that are wanted, £00. 4 postal will do— it is free. PATENTS Send for free sample 201 Patent Dept., copy. One year’ssub- WASHINGTON, D.C. ill scription 50c. DO NOT LOSE YOUR RIGHTS TO PATENT PROTECTION Before Copotins your invention to anyone send for blank form *‘Evidence of Conception” to be and witnessed. Establish your rights before application for patent. As registered patent attorneys we Bee ge hundreds of inventors all over the U.S. and Canada in the advancement of their tions. Terms reasonable. The form “Evidence of Con marion. *” sample, instructions relating toobtaining of pa patent and fee schedule sent upon request. hem,—a postcard will do. THE.BOY ELECTRICIAN Practical Plans of Electrical A bs gl ts fesplanation ‘ofthe Principles of e ~ lectaleity, $2.00 Postpa . “SCIENCE MONTHLY, 22s W. "Sith St, New York tes domes oun oe thar ADVERTISED | ates semex For SALE FREE Adistéis Sine. In INVENTION And aoe MANUFACTURING SUPPLEMENT. AMERICAN INDUSTRIES, INC. Becontree are being spent NOW for new ideas of all kinds. ever before has the demand for good thi PROTECTED igs OWEN PATENTS been so en _ —- to the man who will but use rains. Send for my four free books and find out what ‘inventions are needed. THESE ARE FREE! PATENTS — a 72- ited, for ae: PATENT are x “pee for OWE PATENTS owith ideas desired; PAT ENT PROMOTION — tells “how to sell your Patent, etc. TH “we without charge to sell your idea by advertising it and otherwise putting you in touch with prospective buyers. Send sketch or ee for res opinion as to pasemsalelty.§ cost atent, etc. Advice ccsts nothing. Write today? for my books. A postal request will do. RICHARD B. OWEN, Patent Lawyer eo ep h Wasa, D. | on chy INVENTORS. Send us a sketch, model, or photo and written description of 3 invention for advice regard- ing patent protection. No charge for this service. Patents We Secure Advertised Without Charge in POPULAR MECHANICS MAGAZINE 20 years’ experience. Prompt personal service. Our experience and knowledge in patent matters often enable us to advise regarding patentability without — to the inventor. Particulars free. Write us today TALBERT & TALBERT Patent Lawyers 4621 Talbert Bldg., Washington, D.C. Wrestling Book FREE pea celf. ve a " ete pa a Fee at see Burns ae mt science and a abie = fests , stating your age. Farmer Burns School of Weesllng, $208 Ramge Bide, Omaha, Nebo 112 Popular Science Monthly Once a month clean off the top of the oven, the place under the oven and take off the small clean-out door. See that the smoke pipe fits the chimney tightly and that the inside of the chim- ney is.closed off about 6 to 8 in. where the pipe enters. If the fire-bricks are loose get a little fire clay and fill the joints. Keep the fire up even with the top of the oven, rounding off the top, but not having coal up against the lids or running out over the oven. : Turn shaker handle over quickly as far as it will go and then back. Both motions should be continuous and rapid. Repeat until free from ashes and clinkers. If the range ‘has a flat grate use the poker to clean off the top COND “The average range has the same check- dampers as a heater, but it may be seen they are differently located on the range } of the grates. Always allow the fire to have full draft for five or ten minutes before cleaning. Take the ashes from the ash pit daily to prevent damage to the grates. For Baking and Roasting For baking and roasting have the slide open in the ash pit door at HE, have the fire box filled up to the top of the oven and free from.ashes. As soon as baking is finished, close all front drafts, open the check draft damper in the pipe and if the fire still burns too freely slide back one of the lids over the oven about 2 or 3 in. To leave drafts .on after you are through cooking is very wasteful of fuel. To fix the fire for the night run the poker around the sides of the fire, which will clean the clinkers off the bricks. See that the fire is packed down solidly, round off the top so that the coal does not touch the lids or run over the oven. Set the check draft when through with the cooking. You will keep your kitchen much warmer if you let the oven door stand open. For further information ior directions consult your regular range man. Read general rules applying to all household coal-burners. — re ti) m— ee Oh oF KF a ae ee ek

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Sy nn era fe . sot tear! sae tepeiina January, 1919 _ Gutter-Spout Directing Water IF YOU HAVE AN into Two Trenches A T - A T Sy INVENTION AND DESIRE gy roencer in irrigated districts TO LEARN HOW TO frequently experience difficulty in SECURE A PATENT, send for Our Guide Book, HOW TO making water flow into two different GE ATEN F lateral trenches when the supply is T A PATENT, sent Free on request. Tells our Terms, Methods, obtained from one hydrant. Usually || °c: Send model or sketch and description of your invention and we the soil under the spigot is washed will give our opinioh as to its i ete ee ee ee away, and the water, seeking the low- patentable nature. 7. est level, is soon flowing into one my UMM. ui chad cncdecoteseceubGaneWaieneuy wee trench only. R A N D O L P H & C O. STREET A Western ranchman has effectively 130 F St, N. W., Washington, D. C. SOHO HOO e ee eee ees eseEseseeeeeeeeeseserne Cee w rere eee renee PATENTS Trade Marks aeetarvevereuel solved this problem, and at the same time has found serviceable use for a lot of old tin gutter troughs which were : discarded during recent repairs in his Don t Wear house. The -troughs, as _ illustrated, T are cut into 2-ft. lengths, and into a russ the middle of each piece a semi-cir- Brooks’ Appliance, the cular sheet of tin is soldered. The | ] Woncertul” tentiie maven, that.” irtigation guide when completed is | | tia) “No opnoxivus springs = embedded in the earth, with the cen- — MR. C. E. BROOKS sepeareeteeaatad tral tin member directly in the center Brooks’ Rupture wee of: the stream coming from the faucet. a. gutomatic Air Cushions. Binds, and draws : ‘Obviously the flow of water is evenly | | limb, | No salves. No Hes. "Durable, cheap. Bent Send sketch or model divided and sent into the two trenches | | Catacg aii menalre blanks ‘mailed free. Send =} for actual search and : C. E. BROOKS, 255 State St, Marshall, Mich. | | fA CaORA AO CL od : let of instructions on Here is THE ciec- patent practice and trical ine for you. - For the Dabbler and the “How-to-make-it” 4 Chuck full of experiments and the latest electrical doings Non-technical— in plain English. One of the foremost authorities on WIRELESS in U.S procedure. Prompt personal service.... Geo.P Kimmel Patent Lawyer 39-M Oriental Bldg., Washington, D. C. CPSATEVECCULecQvIareeeireassdjecas eeecuraranrithes 90 big Over 1 articles One ame: will cone At All Rows vs Stands 20c $2.00 a year Send Soe ‘or 3 numbers The Electrical Experimenter 235 Fulton St., New York PATENTS »|| LACEY & LACEY Attorneys-at-Law — Patent Practice Exclusively Solicitors of U.S. and Foreign Patents Trade-Marks, Copyrights 646 F Street, N.W., Washington, D.C. on) LeU EReveeavrereaearionpt ease { Our facilities for securing patents enables | | us to give prompt and reliable service at jf 4 reasonable rates. Inventors are invited || to write to us regarding questions apper- jf taining to securing patent protection. ff i) All matters receive prompt attention jf # Send for ‘blank form of disclosure to protect your rights until filed in the ii patent office. Book of instructions and i] blank forms are free on request. - A. M. BUCK & CO., Patent eee 510 Second National Bank Ridg. By means of a division in the gutter- pipe, water is deflected in two directions as desired. The earth beneath the Write Us for Our Inventors’ Book THE BOY ELECTRICIAN. _ Practical Plans of Electrical ? hydrant is protected from erosion. PATENT-SENSE Apparatus for Work and Play with an Explanation of the Another great advantage of this simple Principles of Every-day Electricity. $2.00 Postpaid. “oy : : . UMC ESTABLISHED 1869 device is that it permits alteration of Popular Science Monthly, 225 W. 3Sth Street, New York the flow between the two trenches by DATENTS PROCURED and Competent Patent Service merely moving the trough slightly in TRADE-MARKS REGISTERED By a Former Examining Official ither di ion.-— Eighteen Years’ Experience. I i d either direction.—JOHN EDWIN HoGcG Eighteca eet nstructions an NORMAN T. WHITAKER ° ROBB ROBB, i How to Prolong the Life of ee ee and — oe adhe 280 wenn pp D.c. Flashlight Batteries eee He 106 Soe ee INQUIRIES INVITED HE life of a flashlight battery can be increased if it is treated in the following manner. Before installing a new battery, take out the individual cells and give them a coat of sodium silicate, or water-glass, as it is com- monly called. The entire cell should be coated, with the exception of the brass cap on the carbon andthe bot- toms. After drying, the battery may be reassembled and put into service. ALL BUSINESS GIVEN PROMPT AND PROPER ATTENTION This treatment prevents the drying out that always shortens the life of st Wacnin ae astne | WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, B.C. 118 Terms Reasonable Highest References Promptness Assured Best Results Send drawing or model for preliminary examination

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PATENTS |

]F 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 ‘Invention and a description of the device, explain- ing its operation. All patents secured by us are described in SCIENTIFIC AMERICAN without cost to patentee All communications are strictly confiden- tial Our vast prac- tice, extending over a period of seventy years, enables us in many cases to advise in re- gard to patentability without any expense to the client. Our Hand-Book on Pat- ents is sent free on re- quest, This explains our methods, terms, etc., in regards to Patents, Trade Marks, Foreign Patents, etc. Munn & Co. SOLICITORS OF PATENTS 683 WOOLWORTH BLDG., NEW YORK and 627 F STREET, WASHINGTON, D. C.

NEW. game has been devised, involving the old war tactics of catapulting. The device is known as a catapult. Instead of throwing stones or arrows, rubber balls are propelled distances ranging from 2 to 75 ft.; and, instead of city walls, a skeleton target lies flat on the ground. The target is usually placed by an opponent, and is located at an unknown range, but within the limits of the catapult. : The catapult has a moving lever A (Fig. 1) that is hinged to the base ‘B and a strong spring C to draw it forward quickly. In t}e lever are cuplike holes in which a ball is placed after the catapult has been set, and Popular Science Monthly A NEW GAME - CATAPULTING By (Farles M. Miller

when the lever is released it casts the ball forward. If the lever has a full swing, it will cast the ball forward, but very little upward, as shown in Fig. 2; and, while the ball will be projected with con- siderable force, it will not gosofar, If the lever is stopped part way forward, the’ inclination of the lever will de- termine the direction the ball will take, usually at right angles to the lever, or will leave it at this angle, which is shown in Fig. 3. If the lever is stopped far back, the ball will be flipped up in the air, but will make lit- tle progress forward, as will be seen in Fig. 4. The setting, therefore, that propels the ball for the greatest

-— = oo sd ~~

Fig.2

Details of the pieces for the making of thecatapult and the assembled parts, with a diagram showing how the position of the lever affects the course of the ball. When the lever is vertical the ball shoots forward but not upward 114

e. tan 2h toe 3 eee |e Ole ee ee ee ee at a te ant a Pa a ae ae a fant ° Oh aad beh Ot OO wtlUC htlC(<iCr Hh); elLCUltltéCelCUCOO etl ee ae ee ae a te tiene SS O26 2 426 22 26 22 8 2c . = TH eas bee ah tte

Page 111

ly Jt January, 1219 distance will be with some elevation | but not sufficient to waste energy in merely getting height. It is easy to understand why there are so many possibilities of range in the game. There are many combinations that may be effected by the device. The lever may be drawn down to the last notch of the catch D (Fig. 1), or it may stop at two other points or notches, giving varying tensions as a starter. As mentioned, the lever may be allowed its full swing to the vertical position, where there is a permanent stop, or it may be stopped at several points by inserting a rod in the holes of the. box. The holes are labeled E, F, G, H in Fig. 1. Other Combinations . There is another series of combina- tions that may be used as distance modifiers. The three pockets shown in the lever (Fig. 5) have a varying effect from the longest to the shortest radius of the lever. The outer pocket, I, will cast the longest distance, be- cause its arc is greatest, and the inner one the shortest distance, because its arc is smallest. These conditions make. variations in the former combi- nations. For instance, if the lever is at full tension, the stop at F, and the ball placed at K, the cast will not be so great as it would be if the ball were placed at J; and so on. Another variation of conditions is formed in the use of a hard and also hollow rubber ball. Three other conditions may be obtained by the elevation of the front end of the cata- pult by means.of a brick. Raise it to the height of a brick flat, on edge and on end. Much experimenting is possible with all these combinations, and it is a good study for a boy. If records are made of try-outs, considerable calculations may be made. In try-outs three casts should be made, the results added and divided by three for the data record. If an operation is faulty, it should not be counted. The try-outs should all be recorded in good form for future reference. To Construct the Catapult The base B, Fig. 1, is 24 in. long, 35 in. wide, and 134 in. thick. The sides are each 15 in. long, 8 in. wide, and 34 in. thick. It is best to cut away the base for the length of the side pieces, as shown in Fig. 6, for appearance, and the front ends of the sides rounded at the top on a 11%-in. radius and the back curve to corre- spond to the movement of the pro- pelling lever, which has a radius of 614 in. The center of the back curve is on a line with the upper side of the base and at the bottom end of the lever. The propelling lever A, Pie. 1, is 13 in. long, 2 Vf in. wide, and 34 in. thick and is hinged to the base with a large strap or door hinge less than 2 in. wide. The front face of the lever, when stand- ing in a vertical position, is 8 in. behind the front end. Three pockets 1 in. in BHOFRBEREBEHRE BERR RHBFeSESB RRB RBBB BBE HBR AORRBRBRBER RB Ae es ; Pa $5 Ammonium Chloride Sulphite Dioxide Sodi of Zine Sodium Carbonate Carbonate Sodium Borate One Standard Washbottle One Conical Glass Measure One Erlenmeyer Flask One Glass Funnel Six Assorte today. coupons for our 160- stiff covers. Cyclo) ustrations, 500 FREE W Zine, Metallic Ferrous Sulphate Calcium Chloride Nickel Chloride Sodium Bicarbonate Nickel Sulphate Chioride of Zinc Hydrochloric Acid Sodium inhate Sodium Phosphate Copper Sulphate 8 ge Acid Sodium Chloride Zine Carbonate Calcium Sulphate Ammonium Sulphate hen ‘Chloride - en Metallic Barium Chloride Lead Ac Tube Test-Tubes One Test-Tube Holder Ten Sheets of Filter Paper IMMEDIATE SHIPMENTS ‘* The Livest Catalog in America”’ Our big, nes new Sg cyclopedia No. 19 is waiting for you. il instruments and apparatus, etc. ireless Scere! in 20 lessons. sent only on receip E. I. Co. Chemica Laboratory Description of the Outfit—t contains the following 44 chemicals etate THE FOLLOWING APPARATA ARE FURNISHED: One Deliver: TY t of 6 cents stamps to cover postage. ELECTRO IMPORTING CO., 229 Fulton Street, New Yous ©» a DO YOU KNOW? "Do you know how to make chemical tricks? Do you know how cloth is bleached? Do you know how to test soil: Do you want to make —— ink? . you know how to test . our: 1 o you know how Chlorine Smoke apd Chlorine Gas (German War Gas), ade: PRs do you know about chemistry gen These sa hundre” ot’ er interesting questions ure answered and demon- strated with our Chemistry Labora- tory which we present herewith. ‘We present herewith to our friends our new E. I. Co. Cher: ical Laboratory which contains real chemicals and ap- paruta to perform real chemical experi- ments. Thiso't t isnot a toy, put up merely to amuse. but a practical labera- tory set with all the chemicals appar- ary to perform real work and to teach the beginner all the secrets of inorganic chemistry. With this out’t we give free a boo containing a Treatise in Elerrentary Cherristry, use ul data a recipes, and mod hp pons and amusing .ex- perim The chemicals furnished are all tech- nically pure and put up in appropriate woceden boxes and glass bottles, and there is a su cient : ua’tity to make = ens of experiments with each. The pparata are of sta dard laboratory a e and quality. Altho all chemicals have nearly doubled in price we have decided not to raise the Price for this out. t for the present. Read the list 0’ chemicals and appar- atafand look at the actual photograph of the out’ t at your left. And order one today! 44 Chemicals 18 Apparata 1 Instruction Book with 100 Experiments ry | PRICE, $5,°° Shipping Weight, 10 Lbs. Can Be Shipped by Express Only Ammonium Ca: nate Calcium Oxide Tin, Metalli a Ammonium Aqua Stannous Chloride Litmus Ferrous Sulphide One Glass Dropper One Spoon Mensure: Glass Tubing One Spirit Lamp. One book containing Treatise on Elementary v2 hemistry and 1 Chemical Experiments © be performed with this outfit. Positively the most complete Wireless and electrical catelog. Ly Faint Treatise on Wireless Tele; tery ie 44 Ib. Beautiful 8 Cyclopedia No. 19 measures 7x5!4”. Weight, Send You a aor ON’T send a penny. Just send . fs Lachnite mounted in a aobds We will send it prepaid iy} Comes merely deposit $4 7 repaid re i) Bang fer 10 full days. it pare ee send us $2.50 a m ye onth until $18.75 bi Send your name now. Tell us which of the i solid Zoid rings illustrated suave you wish i send finger . Be sure to Over 100,009 in Use Mostly sold Geroash recommen: For Personal Desk or neral Office It checks mental calculations Buy through yourstationer ff Writefor 10-dayTrialOffer { P. E. Gancher, A. A. M. Co. | 148 Duane St., New York Agents wanted —* of aie ur friends can te i Eyes decide & > buy it iz been paid. Golden Gem Us PORTABLE iH ai Machine . —ieeeereeeninioes " a g H é r mii ’ wary star aso eae opal | Ag \Multipl Deafness Wilson Common-Sense Ear Drums “Little Wireless Phones for the Ears’ require no medicine but effectively replace what is gor defective in thenatural eardrums, They are simple Gevices, whic the wearer coally fits into the ears ey areinvisible. Soft, safe and comfortable. Write today for our 168 page! FREE book on DEAF- giving you full particulars and op WILSON EAR DRUM CO. 413 inter-Southern Bldg, ‘Louis PICK YOURS erwoods, ‘Genuine Visible Un- derwoods at big saving, 5-Year Guarantee, Try it 10 DAYS FREE. Rent or buy. Write quick for Ofier No.77 « Typewriter Emporium, 34-36 W. Lake St., « which is sincere, reliable, ae What 15° wi, You ‘te: Nation's Capital made at this apd capital. Washington, the home of the Pathfinder, is the nerve center of civilization; history is being The Pathfinder’s illustrated weekly review gives @ clear, im- partial and correct diagnosis o fe — during these strenuous, epoch days, ttle the | of 2Sc in stamps or coin will bring ap the Pathfinder pa on trial. te Pathfinder is an illustrated weekly, published at ee Nation’s center, for the Nation; a paper that prints all the news ofthe world and tellsthe truth and only the truth ; now in its 26th year, This pa- pér fills the bill without emptying the purse} it costs but $1 a year. Ifyou want to keep posted on what is going oninthe world, at the leastexpense clearly, fairly, briefiv—here it is. weeks. 115 i 1 the P Sond ‘ibe to showthat you might like such a paper; and-we willsend the as niece. The 15c does not repay us, but we are glad toinvestin new friends, The Pathfinder, Box of time or money, this is your means. Ifyou wanta paperin your home athfinderis yours. Ifyou would appreciate a paper which puts sation 4

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é Big Money for Boys There is a wonderful opportu- nity right now. for boys who like electricity. Thousands of.men from the electrical industry have gone into the service. But their work must be done. - Boys who are ambitious and will train themselves in spare time can step into good positions and get experience that will give them a real start toward success in life. Good salaries are offered with rapid promotion. For 27 years the International Correspondence Schools have been training boys for success in electricity and over 200 other sub- jects. They will help you prepare right at home for a position in the line of electrical work you like best —or in any other work that ap- peals to you. Thousands of boys, through I. C. S. training, ‘have stepped into fine jobs, but never were opportunities so great as now. Let the I:C.S. help you. Choose the work you like best in the cou- pon below, then mark and mail it today. This doesn’t obligate you in the least, and it will bring you information that may start you on & successful career. This is your chance. Don’tletit slip by. Mark and mail this coupon now. a a a oe ae TEAR OUT HER Coe cme cme mee ee INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7620, SCRANTON, PA. Explain, without ob! me, how I can n qualify for the position, or in the sub, fore which I mark ELECTRICAL ENGINEER OHEMICAL elle Electri SALESMANSHIP Electric Wi ADVERTISING MAN Electric Lighting Window Trimmer Electric Car Ru w Card Writer Heavy Electric »or Sign Painter Electrical Draftsman RAILROADER Electric Machine Designer ILLUS R Ti A DI SIGN a vy nh > MEOCHANIOAL Teonken, Stenographer and Typist ical Dra Cert. Pub. Accoun' Traffic en Machine Shop Practice Comme Ges Engine STATIONARY ENGINEER ivi. ENGINEER CIVIL SERVICE ep Railway Mail Clerk MINE OR ENGR Textile Overseer or Supt. ARCHITECT Se sag Architectural Draftsman avigator Spanish PLUMBING AND HEATING Pou French Sheet Metal Worker Automobiles Italiae Sense Present Occup = Street * and No aS aga City State a diameter are cut in its front face. These pockets should be. 4 in. deep. These may be bored with an ordinary | bit, but it is better to use a spoon- bit. The center of the first pocket is 114 in. from the upper end, the second 11% in. from the first, and the third 114 in. from. the second. For the top of the box a piece of wood %4 in. thick and as wide as the inside measurement of the box, for ‘together while boring the holes. The catapult with the arm drawn back and the ball in place for throwing it this catapult 7 in. long and 214 in. wide, is fastened in 1 in. ale from the upper edges of the side pieces and 1 in. back from the front end. This makes the last stop for the propelling lever. It also carries the spring. The spring is a very essential part of the device. It is a 1-in. closed spring 214 in. long, not including the loops at the ends. Such a spring can be purchased from a hardware store. If it is difficult to obtain a spring just the right length, one may be made from a longer length by cutting it off and turning up a loop at each end. The spring is shown in Fig. 7. The attachment must be very secure. If eye-bolts, as shown in Fig. 8, are used, there will be no future trouble. These are not always available, and a large screw-eye may be used instead. The forward bolt or screw-eye is located 1 in. back from the front end of the upper piece in the box, and in the center lengthwise. Thebolt orscrew-eye in the lever is placed 3 in. from the lower end. Method of Procedure Since the spring loop will not reach the eyes of the -bolt or screw, it must be stretched to hook in place. This is not easy to do. Make the attachment to the lever first, and then loop a strong piece of cord on the other hook and draw it through the box. Pull it to place, and with a screw-driver or other metal tool force the spring to one side, kinking it a little until the hook starts into the eye, then release the cord. The sides of the box should be held This is done before they are nailed to the base. Be careful to bore the hole in straight, that is, at right angles to the surface of the board, boring through both in one operation. If the holes are 5% in. in diameter, a %%-in. pipe may be used for the stop. The pipe may be 6 in. long. The holes must be located so that they will be outside of the arc of the spring. To be sure of it, make the locations 114 in. from 116 Popular Science Monthly the outside edge of the semi-circle on the side pieces. The catch and release for the lever, when drawn down, must be simple and effective. The pull on the catch should be straight up from its hinge. A piece of soft steel 7 in. long, 14 in. wide, and 3/32 in. thick will be found very satisfactory. A hole large enough for an 8d common nail is drilled 1% in. from the lower end, and a similar one 14 in. down from the upper end. The notches are shown in Fig. 9. These can be filed into the metal, but a quicker way is to use a hack-saw. A wire and ‘ring (Fig. 10) are used to pull the catch back for the release of the lever. The catch-bar is inserted in a slot that may be made in the base with a compass saw after some holes have been drilled as starters. The. holes must go all.the way through, especially where the catch-bar is inserted. A hole is drilled in the side of the base to the slot where the hinge is located. To locate the catch-bar, draw the propell- ing lever down to the base, then draw a line across the base at the end of the lever, which locates the front edge of the eatch-bar. This bar should stand in a vertical position when in use. There should be a small metal bar projecting gin. over the end of the propelling lever to make a good surface for the catch. The wood will not stand the wear. When It Is Ready for Use The device at this point is complete as far as casting the ball, but some careless person is apt to give the lever a hard knock if there are no guards provided. The guards shown extend to the end of the lever. They are made of flat iron. It will require After the throw the arm stands in an upright position against the stop placed through the sides about 6 ft. of 14 in. metal 1% in. thick. Two holes in the rear and one in the front end are drilled for screws, and to have the heads flush with.the sur- face they should be countersunk. The ‘whole device will present a better appearance if it is well painted. The target may have an irregular form like the walls of a castle; or it may be made up of three laths laid end to end; or a folding target may be made. One person can obtain amusement, but it is more interesting to have an opponent whose business is to lay the target at an unknown distance from the catapult and return the balls to the operator. sas. i aaa

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CRRA

January, 1919 Each turn consists of three trials. To make a score, the balls must hit the target, frame included, before striking the ground or other object. The first hit counts 10, the second 5. With another turn the target should be moved to a new location. The game consists of ten rounds for each side, not counting repeats. If more than one person plays on a side, they take turns. A Combined Knife and Gouge for the Woodworker ‘ HILE at a Western summer hotel, one member of a party wanted some embroidery hoops, and

The eni of the blade is Cutting edge turned over and sharpened so that the cut is made by drawng the knife Fig2 § an old Indian was induced to make the hoops. The hoops were made as ordered, but it was the tool the Indian used to make them that excited in- terest. It was a combined knife and gouge, made out of a thin-bladed kitchen knife that had been curved at the end and then bent over and sharpened all along the edge and around the bend. The knife is shown in Fig. 1, and the bent end in Fig. 2. The way to use it is shown in Fig. 3. The depth of the cut is regulated by the angle at which the knife is held. Timbermen use similar tools for marking lumber, and the Indian may

Fig. 3. How to draw the knife over the. board to gouge out ani make a depress:on have taken the idea from them. But the little knife he used was a most convenient tool and not difficult to make.—TuUDOR JENKS. How to Make a Mat Surface on Aluminum © O impart to aluminum the appear- ance of mat silver, this simple method will be found very satisfactory. After thoroughly cleaning the article, plunge it into a hot bath consisting of a ten per cent solution of caustic soda saturated with common salt. Permit it to remain in the prepared solution from 15 to 20 seconds, then wash and brush it. Place it in the solution again for half a minute, wash it, and dry it in sawdust.

“See Here, Tockstein, We Need You in Our Business” How aPatriotic Letter Carrier Came to ea be Deluged with Fine Business Offers In Fresno, California, there is a wide-awake young man named Tock- stein. Until recently, he wore the blue-gray uniform of the Post Office and delivered letters for Uncle Sam. He was ambitious, and he knew that to get on he must not look for aid outside himself ‘but -within: He had very little time and he was always very tired when he was through with his day's work. But he found a way—and that way is open to you too. The first result of his new way was that he sold 37,744 thrift stamps in one day—break- ing all records—sinply because he had learned a new way to do the work of three people in one short day without getting tired. And the next result was that because of his record- breaking feat, he has had offer after offer from respon- sible business houses at a big increase in salary. He hasn’t decided yet which to take—they are all so good. Now what he did was simple. He sent a coupon Bi i aitehie. | like the one at the bottom of this page for EMERSON COURSE IN PERSONAL EFFICIENCY What It Has Done for Others It Can Do for You R. S. Howland, who owns fruit groves in Florida, found that it gave him 24 hours more a week—a whole day. Suppose you had one day more a week in which to make money, or to play golf, or to run your car? R. F. Brune, a grocer of California, got $3,000 a:year extra in income and cut down his working hours.

Harrington Emerson has applied these principlesto ¢ over 200 factories, railroads, and other organi a- Fd ® tions. They are studied by eTiciency engineers in America, in England, in France, and in other countries who have learned them from Emerson. Every day that you work wrong is a day 4 taken out of your future success. Send the coupon today. It costs you nothing and may mean the doorway to a great new future for you. ww REVIEW OF . Swanson, Secretary of the Fort Pitt Chocolate Company, Inc., got a 33% % raise in salary. E. Q. Cannon, President of the Salt ‘ ake Stamp Company, learned how to quit before quitting time. And 80 it goes with 25,000 men all over the United States. What you get out of efficiency is what you want to get— whether it is leisure, health, money, or peace of mind— that thing you find in it. This Book— 20 Chapters — P.8-M 1-19 In Colors — REVIEWS CO. Illustrated F R E E i 30 Bid Nee Send for this book. It tells you how to take ‘‘A Short Cut to Success.’"’ Some of the Chapters’ What is E ticiency? lor whom is Efficiency? How you are taught E' ciency. Are you ear-minded or eye-minded? Mcst fail- ures are due to guess-work. ou use cnly half your power. To what do some men owe their success ? ¢ It costs you nothing. Send This Coupon It will be a big step ahead and put you on the road to leisure and success. It will give you a wider view of your business. This Course is not an expense. It isn't even an investment for future returns. It pays for itself with the first page of the first lesson. Send for this free book now and 7 start on a new and sure road 7 REVIEW OF REVIEWS CO. |.” 30 IRVING PLACE, ew Wem FP * Gocwpation| <<... 50 5-- siedss - sd eapl eatoeate aan ELECTRICITY MADE SIMPLE ARMATURE "AND MAGNET WINDING : eae . ; H Tousl A book devoid of technicalities. Simple, plain and A necessary Beg ng eR egy AM facts and understandable. $1.00 Postpaid. diagrams, $1.50 postpaid. Popular Science Monthly, 225 W. 38th St., New York | Popular Science Monthly, 225 W. 39th St., New York An Easy Way to Make Money Don’t be content to plod along on a small salary. Be Inde- pendent. Go in the tire repairing business and make $60 or more a week. One man made $45 the first day he received his outft. Others are mak- Send me particulars about your course in Efficiency and Story of Emerson, and your free book, “A Short Cut to Success.” This puts me under no obligation. Peewee meee wees ee eee eee er eseeee® ABD CGE Sos. o's opetvs edhe vaey atest sna ee vena Occupation

ing nee day and hundreds of wide-awake men are making $200 to $500 a month. No experience needed. We teach you how. Very little capital required. But slight risk, as every car owner in your town isa possible customer. Jobs are plen- tiful because tires blow out and puncture every day. e Tire Repair Outfit, $70 Re wil! do as much and as perfect work as the big $250 to $500 vulcanizing outfits. A boy can vulcan- ize perfectlv with this simple machine _ It’s the only vulcanizer that has Automatic Heat Control. It must vulcanize just right. It cart undercure or overcure a tire. uires no watching or regulating. You can learn to do expert tire vulcanizing in half an hour with the Shaler. WRITE FOR FREE BOOK “HOW TO OPEN A TIRE REPAIR SHOP” and complete Catalog, which gives full information. WRITE QUICK BEFORE SOME HUSTLER GETS AHEAD OF YOU. C. A. SHALER CO., 2100 Fourth Street, WAUPUN, WIS. 117

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Popular Science Monthly A Cidinaiion Stock Barn Under One Roof ‘HE principal building on a farm may be a combined cow, horse, and calf barn, as illustrated. It is laid out in the form of a cross; not that this is the most. eco- nomicalshapetobuild, — be 28:0" , loaded on the wagon or spreader either in the barn or outside. The mow floor plan shows how the _ hay is put down through chutes at points where it is *

There are other good - reasons for this shape. Having so much of-his work under one roof saves much labor for the farmer. In.some States the dairy regu-_ grain-bins have 7 most convenient for but it costs less than feeding all the separate buildings. bio | / stock. The large

K | spouts in the cor- 4 ners near the wings, o so that the grain | may be delivered ° m { iit ey (ele) & COURSE IN FEED

close to where it is

fed. It is taken up 7

PFWO YEARS ; = | 36-0, —— | ‘you ARE BADLY it you lack | _- HANDICAPPED Fish School i -You cannot attain business or social & “ a. You .are barred from } sane /9 5 business career, from Re. TET Tl pe the loadin leading professions, from well: 74 paid civil service jobs, from teaching and college entrance. In fact, em- ployers of practically all worth-while positions demand High School train- ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you.

lations will not allow the DUTCH DOORS young stock and horses

FIT YOURSELF FOR A BIG FUTURE 7; fo bees some of Seniatente | ’s broaden your minc¢

to be in the same room with the cows. The ' cross-shape plan gives a three-in-one stable ar- COW MANGERS

eee ee ce ee ee i ee es ee ee ee ee es oe oe

through the door near the silos by using a rope and the steel — alert and cavable o track. The large eS It all s icone pte 9 _ a no ~— eee aia nes em together so far as ers in the way o . From. the first a leseon > the fo the fast you are the chores are concerned, , handling the hay, penn Cones. but keeping them sepa- either when filling uss SPARE TIME ONLY rate by merely closing them or in taking Most people idle away fifty hours a week. the sliding doors. . the hay out, as this Probably you do. ame maly one Gith of your Where a number of is a plank truss barn. 3our present handicap with fa00 ars. You cows and several horses The large mow you, wil gain will well repay the time spent are kept, and there is a | holds 110 tons and TAKE 10 LESSONS FREE s2ceres pnd complete our train- e invite you to School young stock, this makes an ideal arrangement for housing them and for storing hay for feed. There are driveways i OW cet na The cross-shape has its advantages for making a combination stock barn the smaller ones 40 tons each. By the covered passageway the center of the mows may be reached each way through the barn, and yet | none of the space is wasted. There are steel tracks to carry the ensilage and the manure, which may be put in the yard by means of the swing boom, or even when the large ones are full to the peak over the passage and grain- bins, as well as over the cows. As there is only one way to enter the mow through the feed-room of one silo, the upper part may be locked SILOS by fastening one door. There is a water-tank in the horse stable, and water-buckets for the cows; and water | may be piped to the stock pens. The track in the horse stable runs

qualify for the ‘position STORAGE

marked x | into the harness-room, and a carrier High Sehool Graduate... Lawyer | eran 1: BINS can be arranged on which the heavy ...Eleetrical Engineer _.... Business Manager - “ harness may be hung and all shoved SabhsiedGas. Ciertites Pos Asccentent COVERED PASSAGE _y-Hay TRACK

ic Engi _eagge a S Simumea ates back out of the way.—JOHN UPTON. Bo came Engineer — and Auditor few a ee | -wefRelegraph Engineer _....Stenographer owe Renovating and Restoring Luster .-~Wireless Operator Fire Insurance Expert 1 . vunArehitect ..._Sanitary Engineer i on Aluminum Ware Building Contractor _.... Master Plumber "Civil Engineer <ating Ot Pest: Resisnr : ISCOLORATIONS may be re- ~~~ tructaral erent a nara \ moved from aluminum ware and ~_ Shop Superintendent Rae a rma ; the original luster restored if the fol- ...Steam Engineer General Education Course ! lowing directions are carried out. s ee pean Wash the discolored pieces in a solu-

4 j = ANN SAE 5, NS NS AS SNES Eee a SS ne be ad tion composed of 30 parts of borax dis- ) Name ...._ ; solved in 1000 parts of water, adding - Plan of the mow for storing the hay a few drops of ammonia, and then dry- rT temas and the location of the grain-bins ing them thoroughiy.

118

Sees

xcept satan ~ <ot

Page 115

January, 1919 A Simple Base for a Small Battery Lamp S it is often desirable to use small battery lamps when no base is procurable, a temporary base can be easily and quickly made. Saw .a com- mon spool in half, and ream out the hole un- til it will thread in the base of the lamp. A small screw in the side of the spool serves as one terminal. The other consists of a spiral wire extending up in the bottom of the hole and attached to a screw in the opposite side of the spool. The construction of this small battery lamp can be readily seen in the illustration.—L. B. ROBBINS. ;

SPRING WIRE A spool end is used for a minature lamp base Sliding Resistances Made in a Solution with Zinc Plates T is essential in some experiments to have a varying resistance in the. electrical circuit by a gradual, con- tinuous process, and not by steps. There are two convenient forms of sliding resistances. One is a long re- sistance wire stretched backward and forward across a square. wooden frame. Contact can be made at any point by a suitable sliding binding-post. The other consists of a tall vertical cylinder of glass containing a con- centrated solution of zinc sulphate, and having as electrodes at the top and bottom two zine plates, one of which is movable up and down and can be held at any desired point by a suitable clamp.—PETER J. M. CLUTE. Clips to Carry Policeman’s Club on Motorcycle Handle-Bar NEW YORK motorcycle police- man has invented a very useful device for holding his club on the handle-bar of his machine. The de-

The clips on the handle-bar makes a convenient place for carrying the policeman’s club vice consists of two clamps fastened to the arms of the handle-bar. The club is easily slipped into the clips, and the spring in the metal holds it solidly in place. Theclub isin a handy place, andcan be taken up quickly whenever it is neces- sary to use the club.— PETER P. LEMBO.

Make Your Mind a File—Not a Pile—Stop Forgetting By Prof. Henry Dickson ]s your mind like a scrap pile— heaped up with a lot of unrelated, unclassified, unin- dexed facts? When you want to re- member 2 name, place or date, must you grope uncer- tainlyin this mixed- up pile seeking in vain to locate the desired informa-

PROF. * a HENRY DICKSON, ~“ America’s foremost authority onMemory Training and Prine cipal of the Dickson Memory School, Hearst Bldg., Chicago. in embarrassment, give it up? Sum- moned on any oc- casion to give facts and figures—does your mind become a blank? Whensudden- ly called upon tospeak—do you seek wildly to collect your thoughts—utter a few common- place remarks—and sit down—humiiiatcd? Without Memory, all the knowledge in the world becomes worthless. “‘Stop Forgetting’? makes your mind a file—not a pile. I CAN MAKE YOUR MIND AS SYSTEMATIC AND FORGET-PROOF AS A CARD INDEX FILE —master of your mind’s infinite ram- ifications—instead of a victim of its dis- ordered details, My - course of Memory Training perfected by 20 years’ exper- ience, is universally recognizedasthe most thorough, prac- tical and simplest system of its kind now before the pub- lic. My system so : thoroughly trains The average mind resembles the memory that a scrap pile. you will be able to classify impressions, ideas, names, facts and arguments andshave them ready at a mo- ment’s notice. It developes concentration — overcomes self -con- sciousness,

_ tion? And finally, — J StReer

bashfulness—enables you to address an audience intelligently without notes. IMPORTANT NOW No time has been more opportune than the present to train the memory and the powers of concentra- tion. The soldier needs this training to help him to mas- ter quickly the multitude of technical instructions which are part of his military discipline. The man who remains at home needs this training because business from now on will be more in- an than ever before. very man in every place will find a reliable. effi- cient memory an asset of the utmost value. What- evermay be your position, send now for information. DICKSON MEMORY TRAINING HAS HELPED THOUSANDS Mail coupon or send stal for statements om Somme who had exceedingly poor mem- ories and developed them to fection—and men with remarkably good memories, who made them even better. Give me 10: minutes daily, and I will make your mind an infallible classi- fied index, from which guments. a your memory a salary you will.

The Dickson Trained mind ts as well ordered as a _cross- indexed file. you can instantly select facts, Spee, sae, faces, are you can command what SPECIAL OFFER ON “HOW TOSPEAK IN PUBLIC’s This de luxe, handsomely illustrated, richly boun book —regularly priced : $2-—-free to every stude: e who enrolls, will train you to think on your feet—to express your- self clearly, logically and convincingly, whether talk- ing to one person or a thousand. GET MY BOOK ON “HOW TO_REMEMBER” Simply send your name and i, address on the coupon or pst for this remarkable I will also send you k. a free cop copyrighte of my unique Memory Test.

cmicaco

Sp Public (heesSeeneteenl

Prof. Henry Dickson, Princi Dickson School of Memory ” 1929 Hearst Building, Chicago, Ill. Send me your Free Book ‘‘How to Remember,"’ also | particulars how to obtain a free copy of Dickson’s *‘How to Speak in Public,’’ also Memory | Name est free,

e CITY S.ATE

Violin, Hawaiian Guitas ~“ Ukulele, Guitar, Mandolin, Cornet or Banjo Wonderful new system of teaching note music by mail. To first pupils in each locality, we'll give a $20 superb Violin. Mandolin, Ukulele, Guitar, Hawaiian Guitar, Cornet or Banjo absolutely free. Very small charge for lessons onlyexpense. We guarantee success or no charge. Complete outfit free. Write at once—no obligation. SLINGEBLAND SCHOOL OF MUSIC, Dept. 402, CHICAGO, ILL.

tructions. Plays Blue Print Offer

| Build Your Own PH s. We farnis motors, tone arms, case material, blue prints and full ins —_ at — ne tue pro- Les uilding mographs for your friends. . E Ney Write Today for Our Free | CHORALEON CO. 601 Monger Bidg., Elkhart, Ind. any

work, Red Seal Dry Batteries Are Guaranteed to give absolute satisfaction for Automobiles, Motor Boats, Gas or Gasoline Engine Ignition, Medical Batteries, Telephone, Door Bells, Annunciators, Wireless Apparatus or any other open circuit ASK YOUR DEALER

Supplies, etc. NEW YORK, 17 Park Place

Send for Our New Edition of Our Catalog A28 It will be pocket size, 8 x 414 and will contain 248 pages with over 1.100 illustrations. describing in plain, clear language all about Bells. Push Buttons, Batteries, Telephone and Telegraph Material. Electric Toys, Burglar and Fire Alarm Contrivances, Electric Call Bells, Electric Alarm. Cl locks, Medical Batteries, Motor Boat Horns, Electrically Heated Apparatus. Battery Con- nectors, Switches, Battery Gauges, Wireless Telegraph Instruments, Ignition MANHATTAN ELECTRICAL SUPPLY COMPANY, I

ne. CHICAGO, 114 So. Wells St. ST. LOUIS, 1106 Pine St. SAN FRANCISCO, 604 Mission St.

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BROWN’S BRONCHIAL TROCHES ORE throat, coughing, hoarse. ness, loss of voice, bronchial and asthmatic troubles are quickly re- lieved withBrown’s Bronchial Troches. Not a confection but a genuine remedy with _ seventy years of success back of it. Contain no opiates'or other harmful ingredi- ents. hence are especially fine for adults and May be carried in vanity case or vest pocket. coe siete I5¢, 750 @ $r-25 ot aM druagints sad pnp ag Boston, Mass. MAKE YOUR BIKE A MOTORCYCLES = at a small cost, by using our attachable outfit. Fits required. **Used His Four Years’’ Gor 4. Hyatt, of Boreas River, New. York, writes: “‘About four years ago I received my motor attachment, and motorcycle or atiachment, I would rec- ommend them to the Shaw Manufaci- uring Co.” FREE BOOK Write ab wen! for bargain list and free booklet, fully describing the SHAW Bicycle Motor At tachment. M makes, new and second-hand, .00 up. SHAW MANUFACTURING CO. Dopt. 169 - GALESBURG, KANSAS “{ Would Not Part with it for $10,000” So writes an enthusiastic, grateful cus- tomer. In like manner testify over 100,000 people who have worn it. Conserve your body and life first. The Natural Body Brace es WEAKNESS and ORGANIC oe le of WOMEN a N. De- velops otwaks auc figure. ielees restful relief, comfort, ability to do things, health and strength. Wear It 30 Days Free at — Expense Does away with the strain and pain of standing and walking: replices and supports misplaced internal organs; reduces enl.rged abdomen straightens and strengthens the corrects stooping se develops lungs, chest and bust; relieves backache. curvatures, nervousness, ruptures, constipation. Comfortable and easy to Weer, Keep Yourself Fit gee’ today for illustrated booklet, measurement blank, ete:, and read our very liberal proposition. HOWARD C. RASH, Pres. NATURAL BODY BRACE CO., 241 Rash Buildmg, SALINA, KANSAS AGENTS Only One in in the World KEROSENE ‘Gi’ BURNER Makeany stove a gas-stove. Burns justlike gas. Cheap” est fuel known. Wonder- Frog Semmote ful labor saver. Safe. No ® gear to cata or empt Everybody de coted with it. na ey ae a coal makes this burner sell ag ht heh Rips very Write for agency. Thomas Burner Co., 847 Gay St., Dayton, Ohio. Popular Science. Monthly How to Make a Half-Model Battleship Plans and the way of cutting out the blocks to make a relief half-model battleship By Joseph Brinker ERE you are, boys. The illus- trations will give you all the in- formation you need to know how to make a half model of one of the most modern battleships. All that you will need are wood, glue, paint, some tools, and a desire to have a model that will be an excellent ornament for your den. When you read of the patrol work Uncle Sam’s great overseas fleet is performing in the North Sea, and of somewhat similar to those used in our navy. This.is not an exact copy of the United States ships, since the plans of ‘all navy vessels must be kept secret so that enemies may not obtain any in- formation that will be of assistance to them. Nevertheless, the boat shown is modern in every respect, formed to give great speed, and long enough to give the necessary displacement for carrying the largest gun battery now Boat wider at waterline End of superstructure than at upper deck a Center line Water line ' inboard shaft KI Upper deck line . | __Deck (NE Stacks A Sew | & et oe: ve a ae ee ee a | ofere F 3 Bana ) WEF GH! | Tl | Center line oes toa Conning tower turret | i A, 6 I | { "| Fey ; Main deck line re %e (ley “6, socal tice Bil > ti % \loate’as? ve iy rach I jo real wi Rudder a: == ae gee O SS, SS 7 i 1 a LS wat Taghy “lew iat) EPR Hy }— % Vey. 4/2 : 6 -s non OABCD 1 2 3 4 5 7 8 “ WEF EH] Propelier shafts} The section of the midship, showing how to lay out the different curves from stem to stern by the letters and figures representing the cross-section location on the elevation view perhaps some big sea battle which our sailors and those of the Allied navies staged sometime before the Kaiser acknowledged that he was beaten for good, think how proud you will be if you can show your friends a fine model of the type of super- dreadnaught which played the most important part in the fight. The illustrations show a_ super- dreadnaught of the battle-cruiser type, soll Ly oe boy ye; Nise Sez ue Holding block afloat, twelve 14- to 16-in. guns, three each in four turrets located on the ship’s center-line, two forward and two aft. The position of the basket-masks, the conning-tower, and the smoke- stacks are given, together with the position of the secondary battery be- low the main-deck and the contour of a typical bow and stern, _ the _ tion of two of the our propel- -s a ie oe oe a ee ee ee ee Sail t LU oi a2 ae eS. 8 8S Cardboard cut from the cross-sections, as shown on the next page, are used to shape the block of wood; indicating the method of sawing and cutting waste material 120 Jan Sr —, wa S

Page 117

January, 1919 Build Your Own Grandfather’s Clock | with our help Ont We furnish blue prints, fine ishing material and instruce tions. Buy the works, dial, weights and pendulum from usat surprisingly low prices. You make a fine _ profit building artistic clocks for your friends. Gar PR Shame at alt prio Ask for attractive Free Offer CLOCK COMPANY 1663 Ruffner St. . Philadelphia, Pa.

2s ~~ ~- ee

Genuine Armstrong Stocks and Dies Have You a Set aa Kit? —:

Some of the advantages of Genuine ARM- | STRONG Stocks and Dies: i They can be adjusted to the variations in the size of fittings. : Results are accomplished with less work and time. The Dies are interchangeable in the stocks and they can be shar pened without drawing the temper. Our catalog tells the rest ofthis interesting story; send for it to-day. THE ARMSTRONG MFG. CO. 337 Knowlton Street - Bridgeport, Conn. “DON'T SHOUT” “J hear you. I can hear now as well . asanybody. ‘How?’ With § THE MORLEY PHONE,

I’ve a pair in my ears now, but y are invisible. I would not know I had them in, myself, only that I hear all right. “The Morley Phone for the is to the ears what glasses are to the eyes. Invisi comfortable, weight- less and harmless. Any- one can — it.” Over one hundred-thousand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, Perry Bldg., Phila.

Bit’ Vulcan” Ink Pencils The ONLY perfect, non-leakable i pencils ‘at moderate — ” Sizes— 4% and 5% Order inches. Extra Sisze— today, $ 8 inches(black only) $1.50. e Your name in gold inlay—$.%5. FREE—Liberal supply of ink with retail orders. Agents wanted. Big profits J.L. ULLRICH & CO., 27 Thames St:, New York

Two

er & ‘FZ Print Your Own cards, circulars, labels, tags, menus book, paper. Press $6. Larger $20. Job Press $5 up. CUTS EXPENSES IN HALF.

_The black of wood as it is marked with lo- cation figures and the cardboard forms to the top of the smokestacks. It gives a true form of half of the ship, and should be mounted on a painted backboard about 60 in; long and 12 in.

Manner of gluing several pieces of wood to- gether to make a large block for the model high. This size enables the maker to embellish the boat with miniature guns, anchors, flags, and even life- boats if desired. The model is made of pine, since that is the cheapest and easiest to work

Wade I" Cleats 12" long

: ‘ H bi ; § Front ' 12" ’ , We Picture, Wire . — a a 2 } aN > m 4 i vf 60" | % Champfer | Size of the base for mounting the model and the way the wires are attached for hanging it witii. It is glued together as indicated to form a solid block, out of which the shape is cut with a chisel, and then smoothed with sandpaper. To be made realistic, the portion under the water-line may be painted a bright red and all above the water-line

war gray. 121 When Machines “Come Across Your machines haven't brains to develop the ca- pacity that is in them, but a Veeder Counter supplies a sort of watchful intelli- gence which makes them produce to their utmost. A Veeder allows no idling or marking time; it marks up the proper production-rate for a machine and remains to watch out that nothing less goes! A Veeder registers results as expressed in output, and that © is why you can tell the prac- tical value of a machine, and the most productive use of a machine, by the records of Neds COUNTERS The small Revolution Counter be- low registers one for a revolution of a shaft, recording a machine opera- tion. The mechan- ism of this counter will stand a very high rate of speed, making it especial- ly suitable for many types of small machines, and most adapta- ble for experimen- tal. work. Will subtract if run backward. Price, $1.75. The Set-Back Rotary Ratchet Counter below is for larger machines, such as punch presses and metal-stamping machines, .where a reciprocating movement marks an operation. Registers one for each throw of the lever, and sets back to zero by turning knob once round. Supplied with from four to ten figure-wheels, as required. Price, with four figure-wheels, $10. (subject to discount). Equipped with lock and keys

to prevent tampering by machine operators, $1.50 extra.

There’s a Veeder Counter just fitted for the machine you have in mind. If it’s not shown here you'll find it in the Veeder booklet. Write for copy. The Veeder Mfg. Co. 44 Sargeant St., Hartford, Conn.

Page 118

LOT PLE AE ere

FOR THE MAN WHO CARRIES TOOLS

This Handsome, Substantial Harness-Leather TOOL BAG Combines all the good features of the various com- mon leather bags. Strongly built for rough usage. Bottom is three ply and steel studded. Has saw and bit holder, hand strap and shoulder strap with pad. A mighty good all around tool bag. Six sizes ranging from 14x 8 inches to 24x8 inches. Show this ad to your dealer and insist on the genuine KLEIN tool bag, or write us. Our Illustrated Tool Catalog sent you Postpaid on Request. MATHIAS KLEIN & SONS, Mfrs., Canal Sta. 3, Chicago

BATTERY CHARGING 4! Pays BIG PROFITS | No special electrical or all experionds necessary sae oe me can operate HB eg equipment, little at- tention and no extra help. M any HB owners are clearing $100 to $150 Extra Profit Every Month Some even more than this. You can make big profite teo. This HB 500 watt Charger pochetwes 3 auto storage batteries at re with curren’ = only 12c to l5e fo $1 50. Big profits cin a s 1 Puts ne Money-Maker in Your Garage

ae an

Balance in 9 monthly payments of $206 each, which earnings should easily pay, with profit besides. Write for f: ull particulars, or send $15 first payment with trial order and get charger atonce. Under absolate snone’ guarantee fn ordering from this Delay sii means lost profits. Write or wite today HOBART BROTHERS COMPANY e Box Sl, Troy, Ohio

| Tool Cases For Machinists and Tool Makers, none better; seventeen styles. Quar- tered oak‘°and covered. Ask for booklet “Built for Service.”’ The Pilliod Lumber Co. Swanton, Ohio Bartlett PROP-FORSED Snips $2.40 to $5.50 zee on pe oy Mgrocble stent, drop f <—¥

. . - 650 oie ' FOLDER REQUEST BARTLETT MFG, CO., 38 East Lafayette ate Datroit, Mich. THE MIDGET SLIDE RULE will add, subtract, multiply, divide; solve problems involving even and unéven roots and powers. Also gives the logarithms of numbers and the Sines and Cosines, ‘lan- ts and Cotangents of all angles. operation is yery sy sinple: out auiekly any mathe’ ly made of metal. Pm “for use. vie the pocket, 344 inches in diamete: Price with instructions, $1.00. Your money back Uf you are not satiasied. Gilson Slide Rule Co., Niles, Mich.

TOOL CASES Machinists and Toolmakers Dect built most practi Pec. an ton of ‘Too! market, We x 2 direct iS money. an you or- porratend '

Popular Science Monthly Index for Fluting Columns on a Shaping Machine HE fluting or beading of a column ‘or a table leg is apparently a simple piece of work, but it requires a de- | vice like this to do it economically and accurately. Work of this sort is usually done on a shaper, and an index similar to the one illustrated is a necessity in a shop that does miscellaneous work. The base A may be made in any

N \ / | \ WAM / dr || Gy “YL yy , \\ as TY GORE IK kp} VERN Z wW A \ Ys ¥ HHS] Vv 7/,

’ Lo eee wot

An index head for mounting on a fluting ma- chine to space the flutes on the circumference length, but 6 ft. will allow a column 41, ft. long to be handled between centers. Itshould be made of straight, well seasoned wood cut away at B to permit the shaper head to run close to the edge of the base. The head of the index C consists of a threaded block mortised into the base and pinned as shown at D. It is plain that the lower the center of the column and the lower the cutter is set on the head, the less vibration there will be on the work and the results will be more satisfactory; but the capacity of the index will be greater if there are two centers instead of one, so that columns of different diameters can be fluted. The screw at E should be not less than 1 in. in diameter, or it may not be rigid if it projects more than 2 in. from the head to reach the column at F. A stout spur center at G may be made by turning in a screw and filing it to a point. If the screw E is loose enough to turn easily, it may turn back as the work proceeds; but this may be pre- vented by boring a hole at H and driving in a wedge-shaped pin, so that it will bear on the screw. The essential mechanism of the de- vice is the traveler J, which slides in the groove K of the base and is ad- justable to different lengths. It is held in place with pins at L. Thespur center 7 must exactly coincide with that of the head. The indispensable part of the index is the plate N, which consists of a piece of hard wood, or, better still, a piece of veneer. The edges must be scored with slots spaced accurately on the outside as at O. A plate may be made for each num- ' ber of cuts desired, regardless of the diameter of the column, but one may be used for different spacings. For 122 YY, /; Wht Hie 44 instance, a plate with twenty-four scores or saw kerfs in its edge will index - any column that requires in its cir- cumference 2, 3, 4, 6, 8, 12, or 24 flutes, - The square hole in the center of the plate fits closely on the square end Q of the plug R, which carries the index plate and turns in the hole S in the traveler block as the column ig turned. It may be made to work easily by waxing it. .The spur center M of the plug and the spurs 7 on the face of the plate should be made of heavy screws turned in, and the center spur VM must be filed toa sharp point and the spurs T filed somewhat like an awl point. The metal washer at Y will per- mit the index plate to turn easily by reducing friction, which causes the plate to jump when it is moved forward for the next cut. The back of the index plate, the face of the traveler block and the washer may also be waxed to reduce friction. When the column is set in place between the screw center G and the plate center M, it and the plate may be turned by hand. The piece U may be screwed on the side of the traveler flush with the face, and scored at a point that coin- cides horizontally with the center of the plug M@. The scores O in the edge of the index plate and the scores V in the piece U should be made with the same saw to insure a uniform width to re- ceive the feather W, which acts as a lock to hold the plate rigidly while the knives are cutting. The feather W should be filed slightly wedge-shaped to fit the scores closely. By turning the index plate N until a score in its edge coincides with score V and in- serting the feather W, the column will be held firmly while the shaper is doing its work. When the flutes in the column are cut, they will be as accu- rately placed as are the scores on the edge of the index plate, and any inac- Ww Ww _

; ——— 1a ab ws an ve :

How the work is mounted on the ma- chine and in the index head for fluting curacy in the plate scores‘ will be in- creased or decreased as the column is larger or smaller than the index plate. The bottom of the tenon of the traveler V should be saw-kerfed as at X, and these filled lengthwise with a tongue, glued to prevent the wood from pulling out by the draw of the pins L. The holes in the tenon to receive the pins L should be bored slightly higher than the holes in the base, to draw the shoulder of the tra- veler into close contact with the top of the index.—CHARLEs A. KING.

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l- e it 1e d ie eo January, 1919 These Are The Hours That Count Mot of your time is mortgaged to work, meals and sleep. But the hours after supper are yours, and your whole future depends on how you spend them. You can fritter them away on profitless pleasure, or you can make those hours bring you position, money, power, rea/ success in life. In these days, when men are being called to the colors from office, store, shop and factory, important places must be filled quickly and the boss wants trained men to fill them. You men of middle age, you who are too young, you who for one reason or another cannot go, this is your chance to serve your employer and your country and at the same time win promotion and a salary that will mean more comforts and happiness for those dependent on you. There’s a big job waiting for you—in your present work, or any line you choose. Get weds for it! You can do it without losing a minute from work, or a wink of sleep, without hurry- ing a single meal, and with plenty of time left for recreation. You can do it in one hour after supper each night, right at home, through the International Correspondence Schools. Yes—You Can Win Success in an Hour a Day Hundreds of thousands have proved it. The designer of the Packard “Twin-Six”’ and hun- dreds of other Engineers climbed to success through I. C. S. help. The builder of the great Equitable Building, and hundreds of. Architects and Contractors won their way to the top through I-C.S. spare-time study. Many of this country’s foremost Advertising and Sales Managers prepared for their present positions in spare hours under I. C. S. instruction. For 27 years.men in offices, stores, shops, factories, mines, railroads, in the Army and Navy—in every rn of technical and commercial work—have been winning promotion —— cane: que nen +4 =~ shennan and increased salaries through the I.C.S. Over 100,000 men are getting ready right now in the I.C.S. immense tte nanan ba SCHOOLS way for the bigger jobs ahead. Explain, without obligating me, how I can qualify for the position, or in the subject, before which fmark X ‘se | ADVERTISING , RE ENGINEER MECHANICAL ENGINEER Your Chance Is Here! | SALESMANSRIP Electrician Mechanical Draftsman , | O Traffic Management Electric Wiring Machine Designer : BUSINESS (Complete) Electric Lighting Machine Shop Practice No matter where you live, the I. C.S. will come | Gommerciallaw | (Electric Car Running Boilermaker or Designer . ta: ea a ic ita a er to you. No matter what your handicaps, or how small | Higher Accouati ng zeae Electrical Drafteman eee " tant ectri: 2 ine ner oun: your means, we have a plan to meet your circum- | Qnooxkterer Telegraph Engineer» Blacksmith WS : Steno wees and Typist Telephone Work Sheet Metal Worker stances. No matter how limited your previous educa- | Ose Good Engl ish ec AROMITECT cnn STEAM ENGINEER | . . . . al ndow tion, the simply written, wonderfully illustrated I. C. S. | AShow-Card Writer Contractor and Builder MARINE ENGINEER e n man textbooks make it easy to learn. No matter what CIVIL SERVICE Carpenter Retrigeration Engineer’ | Railway Mail Clerk Concrete Builder CIVIL ENGINEER career you may choose, some one of the 280 I. C.S. | eae Geert PLUMBER & STEAM FITTER [Surveying and Mapping Courses will surely suit your needs. Ulustrator Plumbing Inspecto “os Brid s Engineer | Garp t Designer 0 OHEMIST Pl Z + inten —_ e: Structu: Engineer Make Your Start Now! | Bookcover Designer ity FOREMASORENGINEER Municipal Engineer | TEACH Coal Mining NAVIGATION Spanish Wh hi h b cnaaeen School Subjects Metal Mining Motor Boat Rann'g Sregeh en everything has been made easy for you— 1 Hits Schoo! Subiece Metallurgist or Prospector [| AGRIOULTURE woo when one hour a day spent with the I.C.S. in the AUTOMOBILE OPERATING TEXTILE OVERSEER ORSUPT. [1] Vegetable Growing : : : : : | Automobile Repairing Cotton Manufacturing Live Stock & Dairying quiet of your own home will bring you a bigger income, Auto. Electrical Work Woolen Manufacturing POULTRY RAISER more comforts, more pleasures, all that success means | nae ' —can you afford to let another single priceless hour of | Rae spare time go to waste? Make your start right now! | and Employer. This is all we ask: Without cost, without obligating ie yourself in any way, put it up to us to prove how we - SSE Ce can help you. Just mark and mail this coupon. Loa State_ 123

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since 1880—Star- § rett Precision _ Tools have been building their reputation as the leaders among fine measuring instruments. _ This reputation could never have been at- tained had they not always been found to be accurate by skilled mechanics. All Starrett Tools— micrometers, vernier calipers, dividers, gages, levels, squares, etc., enjoy this dis- tinctive reputation. When looking for “accurate” measur- ing instruments — look for the name ‘‘Starrett’’—the words are synony- mous. Write for Catalog No. 21-W It shows many styles and sizes of these accurate tools. ae THE L. S. STARRETT COMPANY The World’s Greatest Toolmakers Athol, Mass. Removing the metal base from the globe without breaking the glass Making Vases Out of Electric Light Bulbs ASES that are both decorative and useful may be made from burned-out electric-light bulbs. Take a burned- out bulb and hold the metal part of it in a flame. After a few mo- ments turn the metal screw cap with pliers until it comes off. Then break the wires holding the two parts together. | File through the top crown holding the glass rod and its filaments. Then break off the crown and take out the rod. Make a stand for the bulb out of brass or iron strips 1-16 in. thick and 1-4 in. wide. This can be done by bending the strips into any desired shape, such as the one shown here, with a pair of flat-nosed pliers.—E. BADE. of metal How to Construct a Sponge-Box or Bread-Raiser SPONGE-BOX or bread-raiser is a temperature equalizer for the housekeeper who finds the fluctuating heat and cold waves an aggravating circumstance in making bread. Hold- An attractive vase filled with flowers Popular Science Monthly Filing through the crown holding the glass rod and its filaments ‘ing the sponge or dough at the proper temperature lessens the time required. for the substance to rise. Such a box can be made from a dry goods packing- box. A convenient size is 20 in. square and 26 in. high. About 10 in. from the bottom of the box is placed a shelf made of slats and strips of wood on cleats fastened to the sides of the box. A second shelf is placed 4 in. above the lower one. The shelves can be removed when cleaning the box. Below the lower shelf a sheet of galvan- ized iron slightly wider than the shelf is inserted. It is curved in order to make it slip in and stay securely. a This prevents scorching of A mounting made the lower shelf when a lamp strips is placed below, and it also helps to distribute the heat evenly. The door is hinged, and fastened with a thumb-latch or a hook and staple. A number of small holes are bored in the lower and upper parts of the sides and in the top of the box to pro- mote the circulation of air. A cork, which has been bored through the center to admit a straight thermometer, is inserted in one of the holes in the top of the box. A Fahrenheit chemical thermometer that registers as high as 100 deg. can be used. To avoid danger of fire, the box ——_[———a —— of Vents WS Sides Vents The -interior- of -the« bread-raiser, shqwing the. location of the shelves and the lamp, also the working plans with details for making the box at home 124 se eh 6h. ua =e er hs Tt ot oe loonl 7 oa 4 ee hse!lCU”.|!lCOUhell TCU UO rTllcCOTT.llCUCtC*?/

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ee = vr Se) slo a oe 1 January, 1919 should be lined with asbestos or tin when a kerosene lamp is used for heat- ing the box. If an electric light is used, ‘the lining is unnecessary. A 16 c.p. light will heat the box amply. A small and inexpensive night lamp is placed in the box, and a shallow pan of water is placed on the lower shelf, so that the _air in the box will be kept moist. - The bowl of sponge or pans of dough -are placed on the upper shelf. The temperature of the box should be kept as near 86 deg. as possible when the bread is being made in the quick way. If a sponge is set overnight, the tem- perature should be kept at 65 to 70 deg. until the dough is made in the morning, after which the temperature may be increased to 86 deg. The temperature in-the box may be varied by raising or lowering the flame of the lamp, or by changing the tempera- ture of the water in the shallow pan. —S. R. WINTERS. How to Keep a Miter-Box from Warping HRINKAGE of the sides of a miter-box does not affect its ac- curacy, but the shrinkage of the bot- tom will throw out of line the cits in the sides, and render the box worthless for accurate work. The illustration shows a simple and infallible means of preventing, or rather counteracting, this shrinkage. It consists, in effect, in splitting the miter-box longitudinal- ly through the bottom and connecting the halves by transverse pins fixed to the box only at the extremities. In practice this result is accom- plished by using two pieces of heavy A split base with cross-pins to pre- vent the miter-box from warping material for the bottom, the combined width of which should be ‘1% in. less than the desired width of the box. These pieces should be carefully jointed and squared all around and the side pieces nailed on. Place the halves to- gether on the work-bench, adjust them carefully, and clamp them firmly together. Bore a 34- or %-in. hole through the sides and the bottom at each end of the box. Insert a dowel, which should give a very light drive fit, in. each hole, and drive a nail through each end of each dowel. This arrangement holds the sides of the miter-box in the same relative position, and permits any amount of lateral movement of the bottom under changing atmospheric conditions. If good material is used for the bot- tom and a good job done, it will pay to go farther by screwing the sides on instead of nailing them, thus making them easily removable when they be- come worn.—HENRY SIMON. When the Blueprint Calls for Close Limits —the best tool made is none too good for the mechanic who values his reputation. Men whose every act of a working day is dedicated to precision. find in proWN © Stapp, | MACHINISTS’ TOOLS the accuracy and dependability re- quired to match their skill. The final proof of the reliability of these world-endorsed tools is attested by three generations of skilled me- chanics. Write Today for Catalog No. 27 Besides listing our complete line of tools, it contains much infor- mation of value to the machinist. Brown & Sharpe Mfg. Co. PROVIDENCE, R. L., U.S. A. ASBESTOS —| BECIt otis, smug satan id. opular Science Monthly, 225 'W. 39th St., New York We are miners and shippers of Crude Asbestos in any quantity. We produce all grades at our world famous BELL ASBESTOS MINES, in Canada. We also card fibres, spin yarns, weave cloths, and make all sorts of Asbestos products. For anything you want in Asbestos, turn to KEASBEY & MATTISON COMPANY Dept. S-4, AMBLER, PENNA., U.S. A. Owners of the world’s largest Asbestos Mines. Arse “KERO-OIL” ENGINE Have More Power— es gang easier —Get a better engine], - —At less cost—Make rey more money — Save Day Engin ‘Offer more fuel— Immediate L22¥ Engine Shipment Direct from Factory—No long waiting—Five-Year Guarantee —. Deets a of Phe we Me —2to -P.—all styles— ly to Bailey Iron Planes| | | sip? Su youset 3s'to tems | Cash—or Payments—or ‘* Bailey ’’ Iron Planes have been in use for : ; if arranged for nearly fifty years, and are the recognized NO MONEY i i ¥ standard for Planes of this type. Write form latest While retaining all the original features, many val- : k, copyrig yanteamprerqnece Suorracuce maveawenct eee | | DOWN te Judce En . n . best workmanship are used in their manufacture. -“ you all about engines and Always insist that your order be filled with fuels, and why Ican sella better Planes made by THE STANLEY RULE & engine at wholesale factory price. LEVEL CO., which carry with them a Iship everywhere in the U.S.—guarantee safe GUARANTEE backed by a Company that delivery—save you $15 to $200. Icanship big has been manufacturing ‘Carpenters’ and Waite me te en oy a te orders. Mechanics’ tools for over half a century. rite me today— Pres. For Sale by all Hardware Dealers WITTE -ENGINE WORKS 2224 Oakland Ave., Kansas City, Mo. STANLEY RuLe & LeveL Co 2224 Empire Bldg., Pittsburgh, Pa. EW DRITAIN. LONN. U.J.A. Largest Exstesive Engine Menutecterer 125

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They Give You Fingers of Steel Look at your hand. It is the most wonderful grasping instrument ever known. Human ingenuity has never produced anything that can compare. with it in versatility—in the ability to grasp everything. But what the hand gains in versatility is at the expense of strength; even Nature could not make it capable of grasping with the utmost firm- ness. You cannot always grip hard enough with the hand alone. REG. U.S. PAT. OFF. PLIERS add strength to the grasp of your fingers. Their sturdy jaws cling, holding where the bare hand slips. Their handles, fitting the hollow of your hand, give you leverage. Where your fingers of flesh will not serve, Red Devil Pliers are your fingers of steel. A pair of “Red Devils” will save you many a minute—many a bruised finger. With them you can do scores of things around the house which would otherwise remainundone, things you thought you couldn’t do. There are over 100 styles of Red Devil Pliers—ask your hardware dealer to show you YOUR fingers of steel. Smith & Hemenway Co., Inc. Sales and Export Office: 263 Broadway, New York, N. Y. Factories: Irvington, N. J. **Red Devil’’ is the Expert Mechanic’s guide to known quality in Pliers, Electricians’ Tools, Glass Cutters, Hack Saw Frames and Blades, Auger Bits, ‘Chain Drills, and Other Hand Tools. A Simple Type of Home-Made Magnetograph T is known that there are continu- ous changes in the direction and strength of the earth’s magnetic field, such variations being at. times so marked as to merit the title of ‘‘mag- netic storms.” The origin of the Mirror... Popular Science Monthly magnetograms. In Figs. 2 and 3 are shown two records recently taken at Washington University, using an American-made galvanometer in con- nection with a circular coil 1 ft. in diameter and containing 800 turns of wire. A narrow beam of light from a 100-watt mazda lamp was reflected from the galvanometer mirror to a ‘photographic plate undergoing a steady lateral shift of 1 in. in ten seconds. In Fig. 2 is shown a record with the coil C laid flat upon a hori- Moving photo plate Galvonometer” coil Fig.1 A diagram showing the way a magnetograph records the strength and direction of the earth s magnetic tield variations noted at any observation station may be remote or purely local. They may arise from solar disturb- ances, volcanic eruptions, or even from local climatic conditions, such as cloud shadows or showers or wind gusts, as recently shown by Nipher. For many years progressive govern- ments have maintained -magnetic sta- tions. The observations at these stations are made by suspended mag- nets bearing small mirrors, which make continuous records of their ever- changing angular positions by the re- flections of the beam of light on a moving sensitized photographic film. | The path of the wandering spot of | light on the film is permanently re- vealed by the subsequent developing and fixing process. More than thirty years ago another method of registration of magnetic disturbances was put into limited practice. This was the registration of the deflections of a sensitive elec- trical current indicator (a galvanom- eter) connected to a simple coil of wire (Fig. 1). Variation in the num- ber of lines of force of the earth’s Fig. 2. coil lying flat on a horizontal plane A record made with the magnetic field which pass through the coil C produces a current through the galvanometer coil proportionate to the time rate of that variation. Hanging between the poles of a steel magnet, N-S,. the galvanometer coil deflects in proportion to the magnitude of the induced current traversing it. Some of the lately developed types of low-resistance, high-sensitivity gal- | vanometers yield extraordinarily fine 126 zontal table-top, and Fig. 3 shows the record with the coil stand- ing on edge, with its plane approximately north and south—a position in which the coil embraces comparatively few of the lines of the earth’s magnetic field. The more violent disturbances indi- cated in the records are due to the proximity of an electric car line 600 | Fig 3. ‘Lhis re ord was made with the coil on edge ; ointing north and south ft. distant. Certain U. S. magnetic survey records show undoubted dis- turbances arising from an electric car line at a distance of thirteen miles from the observing station. It has been suggested that a coil such as the one shown in C, Fig. 1, could be laid upon a harbor bottom, in connection with a shore galvanometer, would indicate magnetic disturbances arising from the steel hull of a passing submarine. But, considering the ever- present normal fluctuations, grave doubt may arise as to the efficacy of such a device.— LINDLEY PYLE. How to Put Packing in an Automobile Pump N packing the circulating pump of an automobile the following method will improve the work. ‘Determine in what direction the shaft runs; then, when winding the strand of packing, wind it in a direction by which the friction of the shaft will tighten up the spiral rather than loosen it, so that the packing will be in a slight measure self- tightening—the reason being the same as for the use of right- and left-hand . threads on the parts that revolve and are subject to friction against station- ary members. A pump so packed will give very little trouble.

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mthly : 3 are on at an con- 't. in ns of om a ected to a late eady 1 in, n0wn - coil hori- and cord and- h its atel h—a races ' the indi- - the 600 he th netic dis- . car niles coil g. 1, n, in eter, nces sing ver- rave y of f an shod e in hen, ing, the the the self- ame and and ion- will ‘high-speed motor the weight of the ‘ pistons was reduced toa minimum, In ‘ many cases these ‘January, 1919 Oiling the Piston Pin on Automobile Engines recent years pistons-have under- gone a marked revolution. With the development of the extremely light-weight pis- tons have given = trouble, and | usually it is be- | | cause of the lack of care in per- fecting the de- sign. In one case a A 8foove cut connect- well’ known car ‘8 Pin with ring slot with aluminum pistons developed a knock after only a few hundred miles of service. The cause proved to be a loose piston pin, and the matter was remedied by removing the piston and fitting a slightly larger pin. But soon the trouble showed in another cylinder. This time all the pistons were altered as shown in the illustration, and no further trouble was experienced. The lower piston ring was removed, and the upper corner of the lower side of the groove was filed at an angle of 45 deg. for a short distance on each side of the pin, as at A; then a small groove was cut connecting this to the pin bearing. The groove below the ring was cut to catch the oil, and it was then drained to the pin bearing, which evidently had not previously received sufficient oil.—S. E. GIBBs. Use Solder to Secure an Iron . Pin in Wood HAVE found that solder is the quickest thing with which to fasten a long pin in a section of hard wood (Fig. 1), glue requiring too much time to set and also preventing subsequent removal. After tinning the pin I ran plenty of solder around it (Fig. 2) just where it emerged from the wood. The Fig.| _-Fig.2 Fig.3 Fig.4 The different stages in making a connection of a metal pin in wood hot solder produced a helpful groove | in the wood (Fig. 3) into which the solder was forced when cold. I then filed the solder flush (Fig. 4). By this method the pin held firmly, and at the same time could be easily removed when necessary.—JAMES M. KANE. REG. U.S. PAT OFF Polished steel gives no hint of its quality—no one can judge the quality of a tool by its appearance. That is why carpenters buy tools by name. They have learned from experience which tools give the best and longest service. The Disston Saw is the saw most carpenters use. “Disston-Saw” is one word to the carpenter. Helearned his trade with a Disston. His boss used one before him. “Disston-Saw” means to the carpenter everything that is needed for best work and long life. To be sure of a good saw, buy the way the carpenter does—buy it by name—“ Disston.”’ The many details of construction, resulting from more than three- quarters of a century of experi- ence, are all summed up for the practical man in this one fact— Disston Saws do the work quickly, easily and right. Disston Saws and Tools are sold by hardware dealers the world over HENRY DISSTON & SONS, Inc. PHILADELPHIA, U.S.A. Canadian Works: Teeagie, Canada DISSTON SAWS AND TOOLS

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Popular Science Monthly

a 5 ee Se mae eRe J Se cae beeioe ead

Outwit Old Man Winter [ DECIDE now to protect your’ car during the coming win- ter with Johnson’s Freeze-Proof. Purchase your supply early from your dealer and read and follow the directions carefully. <A little time spent now in cleaning the ra- diator and putting on new hose connections will save you unlimited time, trouble, worry and expense during the winter months.

JOHNSON’S

is the logical anti-freeze preparation. It is inexpensive—does not evaporate— is non-inflammable—easy to use—and guaranteed. One application will last all winter unless the solution is lost through the overflow pipe or leakage. Truck and fleet owners will find The present high price of alcohol Johnson’s Freeze-Proof a great ~ —its low boiling point—quick eva~ time and money saver. Your oe Se poration and inflammability make trucks will always be on the job and in <p). it impractical. Use Johnson’s Freeze- ei aint tier it will be “Business | aerry Proof, then forget there is such a thing as Usual” for you. a aah as a frozen radiator. ; REEZE-PRoOF ‘ Farmers will find Johnson’s Freeze- jane PROe One package will protect a Ford Proof a utility product—for automobiles yckediatcr af . to 5° below zero and two packages will —tractors—gas engines— trucks —and it protect it to 50° below zero. ‘See scaleon electro lighting and heating plants. | Pagrtroreron of | package. S. C. JOHNSON & SON, ‘ : oe Racine, Wis., U. S. A.