Popular Science Monthly 1919-07: Vol 95 Iss 1

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GULY _ ua 20 Cents

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Bile Mahia Di eS Sha Hak te ig ee Se As 8) Nes PR AD Dn ‘ Jak a 4 j If this Advertisement appeals to you stop at the first tobacco shop and buy a package of ‘Piper Heidsieck

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Popular Science Monthly Waldemar Kaempffert, Editor July, 1919; Vol. 95, No. 1 Twenty Cents; Two Dollars « Year Published in New York City at 225 West Thirty-ninth Street Fighting an Oil-Well Fire It’s a case where “Water, water, quench fire,” doesn’t work By P. Schwarzbach UDDENLY, without warning, there was a loud crash, and a flaming automobile shot up into the air. This happened as the automobile was crossing a bridge over a creek in Drumright, Oklahoma. What caused the accident? Near the creek was a flowing oil-well. Gases from the well had collected along the edge of the creek, and the headlights of the onrushing car had exploded them. Gas and oil will burst into And these fires are the hardest of all fires to fight. Water will not quench them—they must be smothered. Imagine trying to smother 100-foot flames shooting out of an immense gas-tank. This is one of the problems flames ‘at the toss of a spark, and even, as this case proves, from the heat of a head-light. that harrow the souls of the owners of oil and gas wells and tanks. In combating gas and oil fires, the fighters have tried suffocation by steam and by foam. The foam is made by bringing together two chem- ical solutions that produce tough, non-inflammable bubbles. They have also tried cutting off the source of supply by digging a tunnel up to the well and then forcing the oil to flow into it. = é : Oil was flowing from a well in ( Pa ie Me wace= 8 > 7 Humble Field, Texas. It was pouring out of two pipes—one twenty feet A group of men advanced toward the burning well, shielded from the flames by a piece of corru- gated iron; in their hands they carried a long pipe with an asbestos-lined cap at the end othe 15 303084

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_ they dug a ditch in long lying on the ground, and the other an upright one measuring six feet. At the same time a man was mending a broken power line on the floor. A spark!—and flames ~ shot out of both pipes. How did they tackle it? In the first place, they chopped down the trees near by. Next they sent for all the boilers and pipes in the vicinity, and in the meantime built around the well a circular levee one hundred feet in, diameter and three féet’high. Then line with the flaming pipe on the ground and placed a slice of smokestack in its mouth. The other end of the ditch ter- © minated in a circular depression some dis- tance away. Then they contrived an iron cover for the from the boilers were turned on the pipe on the ground, and its flames were forced down the smokestack at the head of the ditch. It was all over in fifteen minutes—but it took fifteen hours to get ready. A gas-well caught fire in Tulsa, Oklahoma. It was inconveniently The flames rushed up the smoke stack and came out at the top, where. upon the smokestack was promptly removed, and with it the flames, An Ounce of Prevention Are these well fires due mainly to carelessness—workmen dropping lighted cigarettes and matches? No—to elec. tricity: both the elec. tricity of lightning and static electricity, The reason that lightning strikes go often in oil- and gas- well districts is that inflammable gases, which have escaped from the wells, fill the air. To prevent lightning fires, pre- vent the wholesale escape of gas. You rub your feet on the carpet and light the gas with a ditch. When all was ready, azroup of men advanced toward the well, each man carrying a shield of corrugated iron. Water was played on them contin- ually. Smothering the Flames They carried a long pipe with an asbestos-lined cap at the end. They fitted the cap over the top of the upright oil-pipe, and its flames were smothered. Then the water and steam Locked in the Cradle of the AT happens to the murmuring pine and the hemlock when war is declared? Many of them cease murmuring, for they are chopped down and sent off to help make ships, air- planes, and the many temporary struc- tures that the work of war demands. When the chopped-down trees have been turned into logs they are sent down the river in huge rafts of their own making. Each raft contains mil- “located in a river-bed. the flaming well. _a big ship minus a keel. A funnel-shaped pipe riveted to a smokestack was sent by wire to the blazing well. It was lowered over the fire, funnel end first; the flames shot up the smoke- stack, which was promptly removed. With no gas tofeed on, the fire went out The fire- fighters stretched wire cable from bank to bank, so that it passed alongside Then they riveted a funnel-shaped pipe to a smokestack, attached it to pulleys on the wire, and started it off just as if it were a parcel basket on a department-store trolley. As the smokestack reached the scene of the fire it was gradually turned until the funnel fitted over the blaze. lions of feet of lumber. Here we see how these rafts are made in Oregon, which is one of the greatest lumber States in the country. First a large cradle is constructed. It looks much like the framework of Then the logs are fitted in; they are held in place by many heavy chains, Power- ful ocean-going tugs tow the finished raft away. Throughout the voyage the In the great lumber state of Oregon rafts are made in huge cradles. Each cradle, which looks much like the framework of a ship, contains millions of feet of lumber The finished raft is towed down the river by power- ful’ ocean-going tugs. The logs are closely watched for any sign of loosening, for a raft of this sort is worth a fortune 16 spark from your finger. What causes the spark? Static electricity. -When you fill a can with oil, the fric- tion of the oil against the can generates static electricity: If the can is not touching someconductor, the electricity itis storing up will have nooutlet. When it has more than it can stand, a spark will jump from it to the nearest piece of metal. One spark is enough to start fire. Therefore a good rule to follow when working on wells is let metal touch metal whenever possible. Raft logs are carefully watched lest they start to slip. This is not surprising, for each raft is worth a fortune. The forests of Oregon cover more than half the area of the entire State, government reports tell us. There you find—besides pine and hemlock— cedar, spruce, oak, ash, maple, ma- hogany, and fir trees. The Douglas fir is most abundant, constituting five sevenths of all the trees in the State. Popular Science Monthly "

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inly to -- ‘opping ‘S and » elec. 1e elec. shtning tricity, that kes go nd gas- is that gases, Scaped lls, fill revent 3, pre- olesale ur feet t and with a your causes Static e fric- erates is not Ticity | When spark piece . start ‘follow metal they ising, more tate, — “here ek— ma- uglas five tate. Fail, 1919 N March 16, 1918, the French destroyer Dunois, under the com- mand of Lieutenant Terreaux, was zig- gagging in the Channel between France and Great Britain, searching for Ger- man submarines. Shortly before one o’clock in the afternoon, a British hydro-airplane, flying over the Dunois, signaled that a hostile submarine was in close proximity. A listener was sent to the listening-chamber. Twenty minutes later the listener reported the sound of an explosion, probably the discharge of a torpedo which had missed the destroyer. By means of the hydrophone, or listening apparatus, with which the Dunois was equipped, the listener was able to ascertain the direction from which the sound of the firing had come, and the destroyer immediately started in pur- suit of the submarine. A French Lieutenant's Invention Shortly before half past four the listener reported to the commander that the Dunois had caught up with the fleeing submarine and was right over it. A depth-bomb was dropped. This exploded forty seconds later, and the submarine was disabled and soon after sank. The hydrophone, the invention of Georges Walser, a French naval lieu- tenant, had stood its test, and the French government equipped a large number of destroyers with hydro- phones of the Walser type. Their success was remarkable. On each side of the submarine destroyer, well forward and near the keel, large lens-shaped patches of steel, By Ernest Welleck In the lower part of this diagram is shown part of the lens-shaped patch of the hydrophone. The little dots are microphones, the sound from which is focused in the dotted curve shown in the middle of the diagram. The listening-funnel, which is supported by an ingeniously designed bracket, is attached to a hinged arm in such a manner that its opening always pvuints toward the center of the patch, while it can be moved to any point of the dotted focal plane by means of a pulley rope around the disk below the , hinge of the supporting arm. The difference in the intensity of the sounds transmitted by the microphones en- ables the listener to determine the direction from which the sound comes bulging outward, are set over holes cut in the hull for that purpose. These patches have many perfora- tions, which are closed by sensitive vibrating plates. The patches form large microphones, which collect the sound waves traveling through the - Spotting and Trailing Submarines by Sound water and transmit them to a receiv- ing instrument in the interior of the ship. The receiving apparatus is placed in a_sound-proof chamber extending from one side of the ship to the other between thetwo microphones. A Wonderful Apparatus Each apparatus includes a sound- collecting funnel, which is held by a rotatable arm in such a position that the opening of the funnel points to the center of the microphone, while it moves with the arm in a circular plane within focal distance of the micro- phone. A pulley arrangement enables the operator to move the sound-collecting funnels at will to any part of the cir- cumference of the microphones. The sounds collected by the funnels are transmitted by flexible tubes to the listener’s ear-pieces. The listener moves the funnel to the point where the sound can be heard most clearly, and the marks of the scale on- the rim of the microphones, corresponding to the position of the funnel, give him the direction whence the sound-waves come. The distance between the ship and the source of the sound is caleu- lated from the vibrations. There is one of these __ blister-like patches on each side of the destroyer or chaser that is equipped with the Walser hydrophone In a sound-proof cell a listener catches every murmur and by turning the handle of the drum _ he moves the listen- ing-funnels to dif- ferent points in the focal plane i u

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. Popular Science Mon; California’s Latest Attraction—Mud Geysers ON the eastern shore of Salton Sea, California, a field of mud geysers recently came into existence. The field spreads over a little more than two acres. The geysers are various-sized caldrons of hot mud. Until fifteen years ago this sea was a dry, salt-incrusted area with a maximum elevation of 265 feet below sea-level. In the year 1904 the Colorado river ran over its banks, and the water entered into the basin, making a lake of 400 square miles. This inflow was stopped in 1906, and since then the Salton Sea has been shrinking. The geysers appeared a short time ago— caused, presumably, by earthquakes in the vicinity. the world. again. Atlantic first. The Début of a Dirigible 8 our picture the R-33 is about to make her début. The signal has been given, the doors are being opened, and she will presently step forth. It takes fifty men twenty minutes to open these doors by means of winches, for the doors are very large. But they have to be, since the R-33 her- self is a monster. She is the largest airship in This début of hers took place at Barlow, England, on March 6. She went up to a height of 2,000 feet and stayed up there three hours beforeshe came down She was so well satisfied with her flying ability that she has decided to make an effort to win that $50,000 prize to be awarded for crossing the © International Film Service © Western Newspaper a : All the News that’s Fit to Print in Bano "Ta man in black is the editor of the Bano daily newspaper of Bano, Africa. At his left squats his first assistant, and at his right the office-boy. This African editor does not have to worry about circulation, printers’ strikes, the high cost of paper, and similar editoral troubles. When he gets a piece of news, he smooths off some slabs of wood, writes up the story in his best editorial style, and then gives the slabs to his office-boy, who runs off with them and hangs them in conspicuous places so that he who runs may read. The only trouble with this system is that nobody makes any money. Our Capital’s Public Waste-Baskets HE Sixty-fifth Congress filibustered to death a bill for street-cleaning Washington. Now, though Congress doesn’t object to dirty streets, the Washing- tonians do. When the fs waste papers began to pile / up in the streets, the na- tives were dismayed until one of them thought of using the wire protector of a tree as a scrap-basket. Now they all do it, and the streets are cleared tem- porarily at least. Making Use of the Dead Ones E who stands on the ladder with an oil-can in his hand once owned a saloon where he sold cham- pagne. As the “emp- ties” increased too swiftly for his cellar’s capacity, he started to build a monu- ment of them. Each circular layer con- tains eighteen bottles, ar- ranged bottoms out, with lights in the center. Re- cently the champagne-seller wisely decided to sell gaso- line, and turned his saloon into a garage. He uses the monument as a pump.

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*Twas an Irishman’s Idea N Irish plumber had to climb a 30-foot ladder to dig a ditch, and, to be sure, he’s talking about it yet. The explanation of the feat is simple. The ditch was dug for a sewer-pipe which was to run from a house on a hill to the street forty feet below. The hill was so steep that had the plumber tried to walk up and down it very often he would surely have slipped and fallen. Rather than risk it, he used a ladder. The ditch is finished, and the plumber is still whole. A Toy-Maker of China ‘THis smiling fellow who is all dressed up in a pair of trousers and a piece of padding is not the tramp he looks. He is a Chinese manufac- turer—a maker of toys. He made all the toys on his stand, carving them out and painting them by hand. Besides being a manufacturer, he is a salesman. After he has made his toys he peddles them through the streets of China. As a result he is able to sell them for practically nothing. China has no toy factories, and so Chinese children must content themselves with carvings like those shown in the picture. But if Chi- nese children are like American children, they will love best the dirtiest, crudest, ugliest toy they own. The Tale of a Totem-Pole ERE is our story of a totem-pole. *The knock-kneed fellow at the foot of the pole is the chief. But how about the dangling child? He is undoubtedly the chief’s son (note the resemblance), and he has died. But why this special notice? Perhaps his father killed him—hanged him or scalped him! There we have it. Unnatu- ral father! No wonder he looks so queer. Back to Peace Paint NCE the stacks of this cruiser were striped and blotched to make her hard for an enemy to look at. Camou- flage was one of the most picturesque things the war brought, but already the word is slipping from the common speech and our warships are putting off their weird motley for new spring coats of peace paint. Swung high in bo’s’n seats, the blue- jackets are changing the funnels back to their conventional gray. The painters start at the top of the tall stacks, and are lowered from time to time as they finish the sections within their reach. Hold Up Your Hoof O to the blacksmith with your run- down heels and get shod like a horse. Horseshoes are both strong and lucky. Of course they are made of iron and are conse- quently noisy, but they last much longer than the very poor leather of today. The blacksmith will treat you just as if you were a horse, hammer the shoe inté shape, and then nail it on while you hold up your foot. The chances are that he would much prefer to shoe you than a horse, since you are not so liable to kick him. Ex-soldiers are used to hob-nailed boots and probably will welcome cheap heeling. If they get the habit, we will all, most likely, fol- low suit and soon go clinking down the street.

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There is not a roof on Manhattan Island large enough The passenger-carrying air- planes of the near future will require an open space of at Dr. Thomson’s plan for New York city is the reclaiming of about four square miles of land between the Battery and Staten Island, and the construction thereon of huge terminal buildings to ac- commodate steamships, motor-trucks, and airplanes. He estimates the cost of this new city at $100,000,000 for airplanes to land on. at least a mile square. Redrawn from a picture © by Success Postal Card Co. { me / A Plan to Extend New York e [Dr. T. Kennard Thomson, whose daring plan for making New York a great port for airplanes is published here, is an acknowledged authority on pneumatic caissons. He has been retained as consulting en- gineer in the construction of many New York skyscrapers, and has built pneumatic cais- sons for important bridges over many of the larger rivers. He was one of the board of five engineers in charge of the con- struction of the New York Barge Canal.—TuHE EDITOR.] 20 By Dr. T. Kennard Thomson, HE problem of the automobile is roads; that of the airplane, land- ing-places. And, just as good roads have followed the invention of the automobile and the automobile has multiplied with good roads in a never-ending succession, so airplanes in commercial use will multiply with properly laid out chains of landing- places and the landing-places will multiply with the demand of the airplane. : At present the location of landing- places is controlled by circumstances. Mineola, set in the plains of Long Island, becomes the airplane port of New York. But itis asif ships coming to New York had to dock at Sandy

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to Make a Great Airplane Port Consulting Construction Engineer Hook and leave their passengers to make their way to the city as best they could. It frequently takes the pas- senger or the mail package coming by airplane from Washington to New York longer to reach Manhattan after landing on Long Island than it did to fly from the capital to the landing- place. Wanted, then—a good landing-place in Manhattan. That means a smooth surface about a mile square. For at present the most favored types of air- planes have to run for about a thousand feet along the ground before taking the air, and, having to land at one half their maximum speed, they need space in which to settle down to earth again. There is, of course, no such space to be had at present on Manhattan Island. Central Park is sacred as the city’s one big breathing-space, and anyway it is not suited to the purpose. The answer, then, is—build such a place. My plan is this: Build a great station for airplanes, steamships, barges, and motor-trucks by extending Manhattan Island at the Battery. It can be done for $100,- 000,000, and the land thus reclaimed would be worth many times that amount, for it would create a new city of some four square miles. . My idea for a Manhattan extension is to construct a sea-wall from the Battery toward Staten Island in such 21 a way that the new Battery will be about the same distance from Staten Island as the present Battery is from Jersey City, and to reclaim the space between these sea-walls—more than four square miles. Wherever rock is near the surface the space between the sea-walls, or coffer- dams, will be pumped out; but where the rock is more than sixty or seventy feet from the surface, the space will be filled with sand pumped in through a suction-dredge having a capacity of 50,000 cubic yards per day. ay, Eventually adequate landing-places will be built on top of the buildings of the new city. The buildings will cover entire blocks, and will be narrow enough to make air-wells unnecessary. These blocks can be any length—1,000 feet, one mile, four miles. There will be arcades at the street level, say every hundred feet.

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Popular Science Monthly wh ee My Lord, the Carriage Waits Little journeys to lands that are still fordless Cotton is the secret of Bombay city’s success. Throughout the city there atemany cotton-mills; and ox-carts are constantly going to and from them, loaded with bales of cotton | ae . © E. M. Newman Not a straw man, but a Chinese jinrik- isha runner ready for a rainy day: the straw hanging from him is his raincoat © Brown & Dawson The dog-sled of the north is slowly giving way to the motor-sled; motor-sleds are now used in Alaska for carrying mail Photograph by Brown & Dawson es © E. M. Newman © E. M. Newman The only time we carry a man on our shoulders is when he has won a game. A Japanese does not need to win a game: he need only have the price of a_ sedan-chair and four servants t Liamas, the pack- 4 animals of South America, will carry a load of exactly one hundred pounds; one pound more and they will lie down never to rise until that extra pound is taken off © Publishers’ Photo Service © Newman Traveltaiks and Brown & Dawson The Egyptian lady sits in a coach that sits on the neck The Chinese enjoys the shade of his front of a camel. What would happen if the camel ducked? porch while he drives his donke y-power express |

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y man, > jinrik- ready iy: the g from —24incoat e we n our when fame. does yin a need price =hair rants awson “Hit by an airplane,” headlines the London Telegraph, with true British reserve, con- sidering that two men driving along a country road were killed in a collision with a low- flying airplane. The machine above smashed into an _ electric-light pole before standing on its head on the roof Look Out for the Airplane! Why we may soon be in need of new safety-first signs Keep your head down when crossing busy air lanes. See what hap- pened. to a derrick that got in the way of a joy rider unskil- ful with his joy-stick The automobilist has been having things his way long enough. Now, as he hears the roar overhead, he knows how we feel when we scuttle out of his way in our Ford. This driver wasn’t quick enough, and the airplane got him Disputing the crossing with the fast freight, the airplane broke its nose against its sturdier earth rival, but it did it so much more impressively than an automobile does it that the line was blocked for half an hour 23 Cow on the track! Landing-places are to airplanes what good roads are to the automobile. Until we have well planned series of landings, a ’plane is apt to drop down in anybody’s pas- ture—and up goes the price of milk

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Popular Science Monthly

By testing the pressure under which variously grained woods break, unusual weaknesses afte accounted for

The stick snapped because the grain slants to one side. It is as weak when spirally grained, as shown at the left

Why Baseball Bats Break RACK! at least. Instead of that, you see the horsehide pop up in a measly little fly right in the short-stop’s hands! broke his bat—that was why it sounded so loud. As he ambles half-heartedly in the general direction of first base, you see him disgustedly chuck the willow to one side. A baseball bat will sustain nearly three times as much weight as a steel rod of the same weight. Why did that infantile attempt at a hit have to break it? The reason lies in the fact that the defective bat was either spiral- or diagonal-grained. Unless the stress on any stick of wood is exerted cross-grain, the wood gives way weakly. Stronger than steel in one direc- tion, it is weaker than corn- ‘cobs in the other. Though the bat looked perfect, it contained a fatal defect. The manufacturer could have told this before the varnish was applied, but not afterward. The Forest Products Laboratory at Madison, Wis., discovered this defect in wood. In the course of its work with Sitka spruce and Douglas fir for I-beams and struts in the Curtiss- De Haviland airplane, the experts at the laboratory You rise from your seat in the grand-stand. You feel certain that the ball is going into the bleachers,

discovered certain finished pieces of wood to be un- accountably weak. It was found that spiraling of the grain or its slanting to one side was responsible, and in the specifications drawn up experts stipulated against a pitch of more than one millimeter in twenty for stressed parts of an airplane. Beads to Protect Corners HEN one room has a cupboard, the space for it is often stolen from the room next door. The result ig that the cupboard’s back, having at least one sharp corner, is bound to protrude. The batter broken. A Tax on Seats in Trees HE long arm of the law reaches everything— even apple-trees. There was a man who owned a garden in which there was a tree that overlooked a ball-field. Every time a game was played, the man who owned the tree brought out eight chairs and a ladder. He fastened the chairs to the tree and then charged admission, five cents for some seats, ten cents for others, making fifty-five cents on each game. Now, the Bureau of Internal Revenue heard about that fifty-five cents, and after due delibera- tion decided that it should be taxed because it came under the head of Admission to Places of Amusement. Whereupon the price of the seats was raised to six and eleven cents, so that the tree might yield up its eight cents tax whenever a game was played. To prevent this it should be strongly made. The corner is bumped and often A metal corner bead is the best protec. tion. It should be nailed to the wooden lath before the coat of plaster is put on. Then, when the plaster is applied, the tub- ular edge of the bead should not be covered, but should pro.

RS fed ~<nn ee warn If you pay to sit in an apple-tree to watch a ball game you must also pay a war tax, says the Bureau of Internal Revenue 24

The tubular edge of the bead stands out even after the plaster has been applied trude beyond the plaster to withstand all hard knocks. The bead shown here is a good-looking one and might readily be attached to the outside of a finished wall, as would be necessary if the wall were made of tiles or cement blocks.

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t is rer, ten tal cec- the ; of hen ub- uld TO - r to eks. e is and hed hed ary | of July, 1919 The Baby Can’t Lose This Shaving Soap. . BRUSH that carries liquid soap “In its handle is the latest help for the man who shaves himself. The bristles, which are rubber-set, may easily be removed ~ for sterilization, and a wet-proof ventilated cap keeps the damp bristles from soiling clean clothes when the outfit is carried in a traveling bag. To use it the owner simply dips the brush in water, turns the cap until it clicks once,—announcing that a sufficient amount of soap has been driven into the brush,—and applies the brush to his face. It is claimed that the handle holds enough cream soap for sixty shaves. VENTILATED CAP BRUSH WET-PROOF TOP SHAVING’ SOAP FEED-CAP Formula for a good lather: dip brush in water and turn the cap just once It’s an Emergency Coat ERE is a five-pieced emergency coat designed by Mr. Felberbaum, a Baltimore tailor, as a safety gar- ment for injured soldiers or civilians. Its distinguishing characteristic is that the various parts of the coat are pieced together by metal eyelets and shoestrings. If the wearer of this garment should desire to detach a sleeve, he need only cut the string that holds the sleeve at the shoulder, and pull off the sleeve. Should he wish to dispense with one half of the coat, he simply cuts the string at the back of the collar. The inventor of the device claims that this coat can be dissected in less than a minute, without slashing or cutting the garment. He also de- clares that the coat of detachable sleeves and back will save lives in case of emergency. Mr. Felberbaum obtained a job as messenger in order to get into the patent office and other government quarters for the purpose of boosting his invention. His deep-laid plan is to skip hurriedly into an office, and, while the recipient is signing for his message, to boost his invention. Mr. Felberbaum made the inauguration vest for former President William Howard Taft and the resignation vest for former Secretary of State William Jennings Bryan. The inventor of this coat claims that it will save lives in case of emergency Low tide is harvest time for the barnacle man Ever Eat a Barnacle ? HE barnacle, pest of the sea, has been revealed in a new light which may be the occasion for a long blast on the horn of plenty. Marine chefs at Long Beach, Cal., have found that it is delicious and nutritious, and are con- verting it into a soup declared to be as good as clam chowder. Already it has become a favorite in many cafés and even in the highest-class tourist hotels of the Pacific Coast city which brought it out. Credit for its discovery is given to Ulpiano Larco, a cook known for years to seafaring men and familiar with all sea growths. Food experts say the barnacle has remarkable food values, being rich in protein and salts. Canning concerns are preparing to conserve the barnacle in great quanti- ties, and a big industry is in sight, according to people who are familiar with the situation. Long Beach ap- parently is the Pacific center of the barnacle world, receiving more of the product than any other coast point. On the piling of the Pine Avenue pier are more than a hundred tons of these, as well as mussels and similar creatures. They are all now being stripped off, and will no doubt be eaten in the form of delectable soups. Already plans are being made to contract for the barnacles removed from the bottoms of vessels that go into dry-dock at the Long Beach shipyards, and these hitherto scorned and lowly sea denizens will find their way into cans. The methods of pre- paring them in edible form are not disclosed, but the mussels generally associated with. them in growth are also used.

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Minds that Work While Bodies Sleep Some authenticated cases of a much doubted phenomenon By Edwin F. Bowers, M.D. HE impossible is the thing we don’t believe; the incredible the thing we have not yet seen: Both are states of mind common to the average human being. That is why any account dealing with manifestations of the subliminal mind—that mind which works while we sleep and at all other times, and which so few understand— must always be bolstered up with affidavits and attestations if it is to carry conviction. That is why the phenomena of unconscious cerebral and bodily activity have been con- sidered, even by scientists, as old wives’ tales. : And yet, among medical reports of abnormal mental conditions, and in the Proceedings of the Psychical Re- search Society, hundreds, if not thou- sands, of well authenticated cases of most extraordinary activities of sleeping persons have been recorded. In some instances the mental feats accomplished far transcended the normal capabili- ties of the individual. Turning Sleep into Money Such a case is the intuition—or perhaps it was the clear subconscious grasp of business detail—of a Russian banker who was addicted to the habit of getting up at night and looking over his papers while asleep. The banker had been examining the prospectus of an oil company about to be formed, in which he had planned to buy an interest. After mature delib- eration with his objective mind * (the mind we use while awake) he decided not to “take a chance.” However, a few days later his agents told him that, following his instructions, they had bought heavily for his account, at the same time showing him a letter in his handwriting authorizing this purchase—a letter he had writ- ten while somnambulistic, and of which he had not the slightest conscious recollection. ‘Within two years the banker had added two and a half millions of dollars to his ac- count—which puts him in the championship class of sleep- walking money-makers. But, while one person does something constructive dur- ing a somnambulistic attack, a dozen do some destructive or absurdly foolish thing. Such, for instance, is the case of an English nobleman who, missing his shirts almost at the rate of one a night, accused his valet of stealing them. The very next night the erratic nobleman was seen stealing out in his pajamas, carrying a_ soft- bosom dress shirt under his arm. Proceeding cautiously to the back of the barn, he secured a spade, dug a shallow grave, and buried his shirt. Investigation showed that all the re- maining shirts had been interred in the same way. ‘She Hid Her Ring from Herself Dr. John D. Quackenbos, of New York, tells me of an instance in which a patient, a young woman well known as a successful writer of short stories, was taking treatments by hypnotic sugges- tion which materially increased her powers of concentration and quickened her imaginative faculties. Through an oversight on the part of one of the nurses, she was permitted to leave for home while in a somnambulisiic condition. When she “‘came to” the next morn- Sleep-walking made millions for a Russian whose wits were keenest when he was asleep 26 ' Popular Science Monthly He might be called a ‘‘sleep-writer,’’ since most of his writing is done while he is sound asleep ing, she found that a valuable diamond ring was missing. Calling on the doctor, she made known her loss, adding that she had the impression that she had given the ring to a beggar. Dr. Quackenbos immediately put her into the hypnotic condition, and gave her strong suggestions to the effect that when she returned to her home she would remember where she had hidden her ring. Within an hour she called up, ex- claiming: ‘‘Doctor, I’ve found my ring in the lining of an old muff—a muff I was going to give away today.” A Sleeping Novelist Dr. Quackenbos himself is a rare and remarkable example of constructive somnambulistic activities, for some of his rather voluminous writing is done while he is objectively sound asleep. It is his practice to arm himself with pad and pencil on retiring. On awaking in the morning he frequently finds that he has covered sheet after sheet of paper with a perfectly coherent essay. It was in this manner that Dr. Quackenbos wrote his fasci- nating study called “Body and Spirit.” In this connection it may be interesting to know that Dr. Quackenbos holds firmly that anyone who will take the trouble to cultivate the faculty can develop a psychic mental stream whieh will inevitably sweep ideas, impressions, and memorizations into objective consciousness, there to be utilized in solving business problems, and in assisting in the conception, construction,

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ee OR |! ee ws C2 WwW Ww ee ™ tN SB ST — = ~* July, 1919 Burying his shirts was the by-night occupation of an English sleep-walker and completion of all work of a creative nature. He advocates that one should com- fortably compose himself and go to sleep for an hour or more with the problem, the story-germ, or what not, firmly fixed in mind. When the objec- tive mind relinquishes the burden of thought—in other words, when the subject goes to sleep—the subcon- scious mind takes the matter up and carries it forward, together with the memory impressions of the subject. The Sleep-Swimmer A most interesting case, showing the unique coordination between muscle and mind in a somnambule, is recorded in which a young man, totally unable to swim in his normal waking condition, was accustomed to getting up at night two or three times a week and swimming across a river two miles wide. Psychologists insist that, were this young man to be awakened while swimming, he would inevitably drown, for his objective mind could not transmit to his motor nervous system the impulses toward actions with which it was not itself acquainted. This is supposedly the same form of mental and muscular correlation that enables the somnambule to walk fear- lessly, and usually with safety, upon some precarious ledge or dizzying height. While the erratic antics of the sleep- walker usually have a “happy ending,”’ the uniformly accepted belief that no accident ever befalls him unless he be suddenly awakened is_ fallacious. Numerous deaths from accidents to sleep-walkers testify to this. A most remarkable case of somnambulism, com- bined with ‘“externaliza- ’ tion of faculties’”’ and other psychic powers, was re- ported by a famous New York alienist and neurolo- gist only a few months ago. The subject was a Ba- varian peasant girl, simple, good-hearted, and very ignorant. The gentleman in whose home the girl worked as a domestic was a student of psychic phenomena and a hypno- tist of considerable skill. Drunkards and sleep-walkers are said to be provi- dentially protected 27 He had, it seems, developed a won- derful telepathic rapport with this girl, and had brought her to his friend, the neurologist, for experi- mental work. Thrown into the cataleptic state by hypnosis, the girl would inhale deep draughts from a bottle of the strongest ammonia, under. the suggestion that it was perfume of roses. She chewed a strychnia tablet, perhaps the bitterest thing in the world, with gusto and relish, under the belief that it was sugar. Blank cartridges were fired off behind her head, without producing a single quaver of shock appreciation. Tested as to her accuracy in telepathy, it was found that she could read her employer’s every thought. Her Mind Saw Another Room The alienist, to extend the scope of the experiment, directed that the girl— or her subliminal mind—proceed up- stairs, enter a certain room (his daughter’s bedroom), and describe what she saw there. After an interval the girl an- nounced that she was in a bedroom, and described in detail the physical characteristics of the doctor’s daugh- ter, a little girl of eight years. Asked to count the number of chairs in the room, she announced that there were nine—two more than the number usually kept there. Thus far the results might have been due merely to the ability of this girl to read the doctor’s mind and to describe what he well knew. But, on being asked what was on the mantel, the girl replied, ‘‘A picture of a horse.”’ Now, the doctor was certain that there was no picture of a horse in his daughter’s room. So, leaving the subject lying on the couch, the ex- perimenters proceeded to the little girls’ room. The mantel contained only the usual school-girl trifles. ‘Just a clever mind-reader, after all,”’ said the doctor. ‘She can’t externalize her seeing faculties. She sees only what you and I have in our minds.” ‘Hold on,” said the doctor’s friend, stepping over to the mantel and pick- ing up the photograph of a horse that was lying flat on the shelf. ‘‘What’s this?” It was a snap-shot of one of the doctor’s horses, taken in the country by his little girl. To explain these things is more dif- ficult than to describe them. It is generally believed, however, that sleep- walking is only a form of auto-hypno- sis. Somnambulism is generally con- fined to children, or to the youthful— in other words, to those happy people who still preserve illusions. Frequent- ‘ ly, however, it accompanies a neurotic disposition; or it may result from great mental agitation. Lady Macbeth furnishes a classic example of this.

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purpose of foiling the plans of germs. HOSE who imagine a railway mail clerk has nothing to do except to kick off the bags of mail at way stations and “use the hook’”’ to pick up bags while going at fifty miles an hour may see the error of their ways from the accompanying photograph showing one of the tests that the railway mail clerks in Canada undergo—and their brethren in the United States pass through much the same ordeal. The test must be taken each year, or there will be no. salary’ increase forthcoming. The case ex- aminer, as he is called, carries about with him a case containing 100 pigeon- holes, all plainly labeled with the initials of a “run”; 1,000 cards 2x3 inches on which are printed just such names and ad- dresses as might be found on letters picked up for distribution; and a set of scales adjusted to weigh to the hundredth part of an ounce. The screens hedge in sneezes so that they will not spread their germs to all the sailors in the barracks HOLDER. 3 _—< a 3 = bp We Now Have Sneeze-Screens ER-CHOO! sneezed the sailor lustily; yet not one of his fellows complained, for he was surrounded by a screen erected for the The screens are made of unbleached muslin. Each screen is tacked to three poles four feet long. In the day-time they are rolled up and stowed away, and at night they are brought out again. Each screen is spread across the head and one side of each bunk, the poles being fastened to the legs of the bunks. As the bunks are placed the saw - in regular rows, this arrangement protects the men on all four sides. latch swings up The popular disease of the day is supposed to lurk in coughs and sneezes, so that a sneeze is no longer considered an occasion for say- ing ‘‘God bless you,” but as a signal to bring out masks and screens.

REMOVABLE BLADE Keeping the Railway Mail Clerk on His Toes The examiner, in the presence of the clerk taking the test, first weighs the cards. Then they are turned over to the ‘‘examinee”’ to sort into the proper pigeonholes just as if he were on the mail-car. When he has finished, the examiner takes the cards from the pigeonholes

This mail clerk will not get an increase in salary unless he can demonstrate that he is worth it 28 U-SHAPED BLADE In this new razor under the remov- able blade and holds it in place Popular Science M onthly New Blades for Old Razors AFETY razors are made go that dull blades may be taken out and newer, sharper ones in- serted. But in the old-fashioned kind the bare blade has to serve throughout the razor’s lifetime. Nathaniel Orr and George Snyder, both of Virginia, have pat- ented a plain razor in which the blades work in shifts. The blade- holder is made U-shaped and hag two rivets running through it. The blade is grooved so that it fits around these rivets, and has an extension, under which a latch swings, locking the blade in place.

{LOCKING LEVER toothed one after another and quickly runs through them. If he finds a card sorted to the wrong railway post-office, he displays it to the candidate, who, if he thinks he is right and the examiner wrong, has the privilege of demonstrat- ing it by reference to his distribution book. After all of the cards have been checked they are again weighed to see if the clerk, not knowing in which pig- eonhole to place some card, has decided to hide his ig- norance by holding it out. In Canada the railway mail clerks are required to sort the 1,000 cards in 90 minutes or less, and to have at least 900 of them correct, in order to be en- titled to a salary increase. The examination also includes a written test in which the candidate must tell in writing how, under various circumstances, he would most expeditiously get a letter or mail-bag to its destination, and show that he knows the ins and outs of the postal laws.

ante ae Oe ab. ote a

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en in- ied ‘ve ge at- che Je- 1as it. fits an ch ce. ins ard ice, ), if ner at- ion ig- ay to in to em en- se. so in ust der he sly to ow ind July, 1919 Calk the Seams with Wax CANDLE and an iron near each other usually means cleaning day for the iron. Not so with the candle and jron shown here. They are waterproofing a tent. Every time rain poured down on this tent, it trickled through the leaky edges and wet the things within. After a few wettings the camper pought a candle and borrowed an iron. First he melted the wax and rubbed it into the in- side and the outside of the cracks. Then he ironed it out with a hot iron. His tent was thus made waterproof and will con- tinue to be so, unless the sun should get hot enough to melt the wax. The first candles were made of beeswax—a liquid secreted by glands in the abdomen of the bee. uses it in making the honey- comb. To abstract the wax the honeycomb must be heated in water, when the wax rises to the surface. When _ candles popular, bees were not able to keep up with the demand; now vegetable and mineral waxes are used. Listen to the Professor of Butchering He’s. making his tent water- proof with the help of a melted candle and a hot iron * ID you study your chops last night?” “No, steaks,’ they whisper to each other. They are sitting in Slaughter-House Hall of the Iowa State College of Agri- culture, where they are learning to be butchers. Iowa College has an Animal Husbandry Department in which men learn to be expert ranchmen and farmers. The slaughter - house is part of this department. The student and the animal enter together, and stay together until the student has turned into an expert butcher and the animal has turned into steaks and chops. Guided by an in- structor, the student kills it, cuts it up, and cures it if neces- sary. We publish a picture of the cut- ting class. The students sit in the gallery, and the instructing butch- ers, with their blocks and carcasses, stand on the platform. They show the students where steaks end and chops begin, where legs and shoulders aeronautics. should be cut off, and all the other _ since birds flew first. But this is not all. secrets of the trade. She pulls the cord, thereby closing a switch which is connected with a signal in the nurses’ room Summoning the Nurse IRST thought: how charming she looks; second thought: what is she pulling? the nurse. The cord is attached to a switch designed for hospital call service, and therein lies its superiority. All the live parts terminate in the wall, so there is no chance of the patient adding electric shock to her other ailments. One pull on the cord closes the switch, and so rings a bell or lights a light or drops a signal in the nurses’ room. It also causes a push button located above the cord to jut out. until the nurse comes. A cord to summon The signal remains ‘‘on’’ Flying Men Must Not Shoot Flying Birds OWL have the right of way in air, warns the director of military This is justice indeed, Recently many Afterward the students come down’ towns along the Atlantic coast have to the platform and put their knowl- been visited with dead-bird showers. edge into practice. Iowa State College of Agriculture has a course for ranch- men. In Slaughter-House Hall they learn to be butchers 29 Aviators flying by a town would see a flock of wild fowl coming their way. They would set their machine- guns and let the bullets fly. Presently a prominent citizen walking below would be hit with a large, bloody bird. He com- plained to the town, and_ the town complained to the Depart- ment of Agricul- ture. Then the Federal migrato- ty bird law be- tween the United States and Great Britain was re- ferred to, and it was found that shooting birds from airplanes is unlawful.

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my

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July, 1919 Miss Rose Murray, of the New York Public Library, is a book-doctor with a million patients. Here she is in her working garb of surgeon’s apron and cheese-cloth veil with eye-holes, diagnosing a case Gaze upon the book- worm. He is fond of paste, and will eat through the dullest book to get it. De- spite his advantages, he is a low insect Trail of the Bookworm Curing a book of a weak back by an ap- plication of paste while a novice looks on and learns how it’s done (At left) Shaking the dust out of a classic. Fresh air and clean surroundings are the cure for bookwormitis (At right) Where a bookworm burrowed. More often, says Miss Murray, volumes suffer at the hands—dirty hands—of people 31 Dirty books, shabby books, books with broken bindings, all go to Miss Murray, who probably holds the record of having opened more books than any other person in the world ‘

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Popular Science Monthly Ju Carry Your Wireless Telephone with You } STOVEPIPE, a little black box, ‘‘We are going to run down the and a combined transmitter and road. Can youhearme?” Said receiver are all you need for a wireless she: “Yes, perfectly. Where are telephone of your own. The stove- you?” The picture below pipe is the aerial, and the little black Both the reporter and the che Oe box hides the mysterious | ———____ hr el telemhenil secret of its success, which By, 4 VO Bes fim with its three stove. I is known only to the inven- pipes. In the ab- tor, W. W. MacFarlane of sence of a stove. . ‘ pipe, a rifle can re- ‘ Philadelphia. place the aerial th You hold up your stove- no pipe, adjust your wave blz length, say, ‘“‘Hello,’’ and tri he will pick up your wave a | and answer. That is what tui Mr. MacFarlane is doing chauffeur wore receivers thi here. He is using three connected with the instru- sli) stovepipes to be triply sure ment. They heard her voice © th of success, for beside him is quite clearly. rif a skeptical reporter. The little black box— Asthis picture was taken he always black—weighs ce: was talking to his wife, who twelve pounds and Is a ag was sitting in their garage foot square. Besides other gh half a mile away. Said he: things it contains substi- at tutes for the audion bulbs, th tuners, and amplifiers. cr e e pe Measuring the Lights of Head-Lamps su PECIALLY equipped laboratories have lately been established se in which light measurements and tests and a great deal of ex- gr perimental work in the field of artificial illumination are conducted se by experts. in An important branch of this work is the measuring of light from fla automobile head-lights; for the laws in most States prescribe certain | th requirements concerning the illuminating power of head-lights. at Our picture shows a woman expert in the New York laboratory 3 about to test a pair of automobile head-lamps. Under the laws te of that State the head-lights of an automobile must give enough | a light to make ob- pI jects clearly visible Y at a distance of ri two hundred feet, nt without throwing a al glare in the eyes of drivers of approach- cr ing cars. The tests pe made in the labora- le tory are official and tk its findings are ac- he © International Film Service cepted in approving tk With a radio compass of this general type ship or rejecting lamps os stations help the transatlantic flyer to find his way for general use. st The New Radio Compass : HE old-fashioned wireless used to send and receive its messages from an umbrella-like aerial or from some allied type. The result was that the electromagnetic waves it sent out traveled broadcast, so that any operator who happened to be listening might hear; and, since there was no concentration of energy, the wireless waves were not very powerful in any one direction, nor well governed taking them as a whole. Unfortunately, this is still true of most sending stations. Receiving, however, has been materially bettered. Now a listener can tell the direction of a sender. The receiver’s aerial is of the type shown above. It revolves about a central axis. When the top edge of the frame “‘points’’ toward the sender, signals come in the loudest. When 90° either way, signals are weakest. Going by the strength of signals, then, a receiver can soon get his aerial “pointing’’ toward the sender, or *‘crosswise,”’ and figure therefrom the sender’s direction. Ship and shore stations followed the progress of the transatlantic With the aid of this apparatus, women flyers with direction finders of this general principle. ’ experts test head-lights for automobiles 32 pe 2

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thly, slow ntor one, Ove- ove- Te. rial ers Tu- ice x— ths 3 a her sti- ibs, S hed ex- ted om ain nts. ory AWS igh July, 1919 Spy-Glasses on Guns Bringing the game nearer with grandfather’s old telescope | By Captain Edward C. Crossman, U.S. A. ARKNESS was creeping into the D grove. Forty feet overhead, in a crotch of a huge limb, some- thing seemed to be snuggled that did not fit in with the usual outline of a black-walnut limb. Vainly the hunter tried to see it. Hastily he drew from a leather case by his side a thin steel tube, possibly a foot long and not much thicker than a man’s thumb. He slipped it on the rifle and tightened a thumb-screw. Again he pitched the rifle to his shoulder. Through the tube the great limb ceased to be merely a blur. In relief against the dark bark were two ghostly crossed hairs, their intersection at the exact center of the circle of light that came from the lenses. The tube crept along the limb to the crotch. The something that the hunter sus- pected did not belong to the tree was suddenly revealed—a sharp ear, a bright eye, an impudent nose with the sensitive nostrils above, set in a back- ground of light gray fur. The inter- section of *the hairs rested for an instant on the bright eye. Bright flame spurted from the black muzzle of the rifle. Something fell into the leaves at the foot of the tree. If you took grandfather’s old ship’s telescope, focused it, and fastened it on a rifle, you would have the primary principle of the rifle telescopic sight. You could not hit anything with the rifle so fitted, because there would be nothing in the telescope to direct the aim. If you carefully fitted a pair of crossed fine silk hairs or the finest possible steel wires in the focus of the lens at the eye end of the glass, so that the magnifying eye-lens enlarged the hairs as well as the image formed by the object lens at the front end of the telescope, you would have the second step of the telescopic rifle sight. If you altered the fastenings of the When the point where the hairs cross bears directly on the woodchuck’s head, it is the moment to pull the trigger STOP CROSS WEB T fit T ij } 1 1 V i Y SELDOM AN ACHROMATIC on EYE GENERALLY A SINGLE LENS CROSS WED STOP. STOP_END 7 Fi Se ay T 1..." ul u v _v W I i The upper half of this diagram shows the old type of telescope sight; the lower half, a later type with achromatic lens. ‘‘Stop’? means diaphragm. Like ordinary telescopes, the telescope rifle sight has a lens (the object glass) at the forward end which forms the image. At the eye end is another lens (the eye- glass) which is a simple form of micro- scope, and which takes the image from the object glass and magnifies it instrument so the junction of the fine hairs and the point of the strike of the bullet agreed at some one de- sired distance away from the rifle, you would have the third step. The power of the telescope rifle sight is low. This at first seems strange, because the more we enlarge an image the closer it seems and the plainer we can see the object. Nine times out of ten the ordinary American telescope sight is less than five power. Here’s the reason. The rifle, in human hands, movesconstantly. Theviselike grip died with the heroes of Fenimore Cooper. Point the telescope sight at a distant brick chimney. If without the tele- scope, we find that our front metal sight moves just the width of a brick in spite of all our efforts to hold steadily. With the telescope it still continues to move the width of the brick. As the image is enlarged five times, the rifle apparently has to move five times as fast and five times as much to continue to swing from side to side of the brick. The result is that the shooter beholds the cross-hairs galloping back and forth across a greatly magnified picture of a brick. With the ten-power glass the effect is just that much worse. Two other reasons, minor but valid, are that the greater the magnification the less the light passed by the lenses— and we must have plenty of light. The common form of American tele- scope sight is a steel tube from three fourths to a full inch in diameter and from ten to fifteen inches long. In the best make the lenses are known as “achromatic’’—which means cor- rected for color dispersion. The old form of cross-hair is giving way to other and more useful forms. Proba- bly the best form for hunting is a little slip of steel running to a sharp point just at the center of the tube. Some- times, to strengthen this, another wire is run across the tube from side to side, intersecting the picket just below the point. Should this be our form, then whenever we touch our mark with the sharp point, our rifle is sighted for it, and the bullet will strike there. The American type. It is good for target work, but not for war. Its The telescope sight as mounted on a sporting rifle. Prismatic glasses will add half an hour to the evening shooting low power makes it excellent for twi- light shooting. The power must be low because, in human hands, the rifle is constantly on the move 33 German telescope sight, showing how to detach from rifle. War also has proved the value of the telescope sight

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A Rat at the Cannon’s Mouth i a cat may look at a king, ap- parently a rat may—and in our picture does—look at a cannon. This particular rat is stepping down gently from one of the recoil cylinders to have a peep at the bar- rel of a powerful mortar which once did its part to make the world unsafe for the Allies. When this picture was taken it was on its way to help boost the Victory Loan in a Western city. When the rat looks into the barrel he will probably not notice that it is rifled— which is rather unusual for mortars. The mortar is one of a collection of captured German guns brought over on a transport as visible evidence. How We Make Marksmen ONE of the reasons why our marines shot so well at Chateau Thierry and Belleau Wood is shown below. section of the naval rifle-range at Great Piece Meadows, N. J., displaying a rear view of a few of the hundred targets, with the mechanism for raising and lowering them in plain view. In one regiment of marines about 93 per cent of the men wore shoot- ing medals. Tree-Top Tea-Rooms HEN the bough breaks the tea- room will fall, and down will come teatotalers, tea-room, and all. But that thought does not worry the folks who are merrily drinking tea in the tree-tops. This is the village of Robinson, situ- ated just outside Paris. It was built in memory of Robinson Crusoe, and symbolizes the kind of time he ought to have had when he came back from his island. Besides these tea-rooms, there are dance-halls, “‘movies,’”’ mer- ry-go-rounds, and many side attrac- tions. Orders taken in the tea-room are sent below in baskets. The baskets are then filled and hoisted up. © Western Newspaper Union Popular Science Monthly ’ Bottle-Holders for Bottle Babies ON’T hold a baby responsible for his bottle. If he is very young he will loose his grip on it and go without a meal. If he is old enough he will throw it away and.smash it when he’s had enough. A bottle- holder like the one shown below will keep the bottle aimed directly at the baby’s lips until you come and get it. He cannot choose but eat. This bottle-holder is made of three metal arms jointed together and having a screw at each joint to keep the arms fast or loose, In this way the bottle may be properly aimed. The bottle itself fits snugly in a wire case attached to a spring, which is attached to the holder’s third arm. Jul:

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This ‘“‘Central’’ Lives in a Trunk A RADIO-TELEPHONE outfit that travels in a trunk makes it possible to set up a sending station anywhere and chat with a passing airplane thousands of feet overhead, providing, to rig the aerials was a bothersome one. of course, the airplane has a wireless tele- phone on board. The radio-telephone came just too late to be tried out in battle. It is an adaptation of the principle of the wire telephone to wireless conditions. As in the familiar tele- phone, there is a diaphragm and a capsule of carbon granules; but, instead of varying the intensity of a current passing over a wire, the radio transmitter varies the strength of a stream of electro-magnetic waves. Let’s Go Truffle-Hunting ID you ever hunt truffles? Not un- less you lived in France and had a truffle hound -—which isn’t a dog at all, but a pig with a nose for truffles. In two country places about thirty miles from Paris the owners have pigs trained for the truffle hunt. The moment a pig roots out a truffle, his master distracts his at- tention and _ abstracts the truffle. Of course the war boosted the price of truffles along with every- thing else, and the roots became as scarce as they were desirable. The Ears of the Airplane HEN the radio-telephone, adapted for airplane uses, was added to the other war-born marvels, the question of how At first a long, single cable was tried out. It was kept from fly- ing up and entangling itself in the machine Flapping Her Under-Water Wings by a heavy weight, and swung 300 feet NE rudder is not enough for a submarine; it must have horizon- tal as well as lateral steering ma- chinery -to assist in keeping on an In the early under-water boats the horizontal. bow rudders—hydroplanes * as they are called—showed above the water when the boat was running on the surface instead of below. or so below the airplane. These long dangling cables were a men- ace to machines flying in formation. They were raised and lowered by a reel attached . to the side of the airplane within easy reach even keel when running submerged. of the pilot’s hand. The more recent prac- tice is to suspend short, weighted wires from the wing-tips or, in some cases, to arrange the aerials between the wings. But it was found that the waves pounded the rudders unmercifully, and so in later types they are ar- ranged to be always submerged. The hydroplanes fold back into the super- structure of the submarine. Prop- erly set, they’d be seen edgeways. The boat in our picture has the ap- “Ny pearance of flap- ping her wings be- cause she is about to fold them. It Can Sail on a Raindrop BATTLE- SHIP on his thumb! Surely he must be Gul- liver and the battleship must belong to the small people of his trav- els. No; the thumb is anyone’s thumb, and looks just as yours would look if we took a picture of it. The battleship is a *4-inch reproduction of the German dread- nought Koenig. In making this small model each part had to be reduced about ten thousand times to keep it in proportion to the 600-foot original.

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Popilar Science Monthly Hopeless, eh? No, reader! Only a test stop which the manufacturers made, starting again without assistance Mud No Obstacle to This Device “TUT, man, it’s impossible with those roads a foot deep with mud.” My friend stepped into his garage, returning with two objects that looked like miniature tractor wheels, which he fastened to the hind wheels of his heavy car. A few minutes later we were literally ‘“‘pad- dling’ through a lake of gumbo, emerging with the radiator as cool as when we started. It is a ring fastened to the outside of each of the driving wheels that does the trick. To - these rings are attached eight blades set at an angle of fifteen degrees, so that they may exert the proper pressure. The blades are fastened to an outside guard ring, the complete device being attached by bolts to the inner ring. When your car won't, this de- vice will pull you out of the deepest mud As easily operated by a woman as by a man, this rim assures the woman driver of her mechanical efficiency Off and On in a Jiffy ANY people will appreciate the advantages of this ingenious tire rim. In case of a blow-out in a rain-storm, you quickly unbolt the rim, take it inside the car, repair it, and then slip it back upon the wheel, spending only five minutes in the rain. No tools are required in operating this rim. It is broken by simply bouncing upon the floor or pavement, and brought back into position by a pressure of the foot. The rim is applied to the wheel in the ordi- nary manner, but is hinged to facilitate remov- ing the tire. It is so constructed that it is inter- changeable with almost any kind of rim without alteration of the felloe or rim-band. Does It Pay to Jack Up Your Gut HEN your tires, guaran- teed for a certain mile- age, start rim-cutting and blowing out before their time, you think hardly of the manu- facturer who tells you that it is due to your own carelessness, but that he will make an adjustment—at his price—with which you have to be satisfied. Did you know that more than one half of the tires that rim-cut and blow out do so be- cause of improper care, such as standing with the dead weight of the car in one position for days at a time, and sometimes months, thus breaking down the tire walls by absorbing oil, grease, and moisture from the floors? ; Does it pay to jack up yourcar? ‘‘Yes,”’ you say; ‘“‘but it’s tedious, dirty work, and I haven’t the time to spare.” You mean it used to be a hard task. It isn’t any more, for with a new automatic automobile jack in your garage your car is driven in in the usual way, the car following the guide, and when it reaches the proper place all four wheels are instantly jacked up without any assistance from thedriver. This the The. jack all ready for car run up on it to is accomplished without lifting the weight of the car; neither is any partic- ular speed necessary. The car is left supported on rubber-cushioned jacks, with all wheels free to be turned or removed. To remove the car from the jack it is necessary only to press afoot-lever,when the car recedes under its own power. The jack at the moment of lifting the car. Think how this device will save tire bills

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July, 1919 Are Wood Wheels INCE time immemorial S the wheels of vehicles have been of wood. No doubt the first wheels were sections cut from the trunks of trees, these being handy and obviously round. After a time, however, our forefathers discovered ‘that solid wheels had their drawbacks. They were very heavy; they would split; they would swell when wet. Then some genius invented the spoked wheel. This was found to be very much better than the old solids. Note the clean-cut appearance that the disk wheel gives toa car. Many advantages are claimed for it Obsolete? It Seems Probable Later came the auto- mobile, and with it side- slips, collisions, and general hard usage. The old wooden wheel could not stand the strain. Then the users and manufac- turers began to sit up and take notice. The wire- spoked wheel was. intro- duced, and answered many needs. Now comes the solid steel disk wheel. Much is claimed for it. Ease in cleaning, ease in tire changing, great strength, lightness, and economy are among them. To remove and change this kind of wheel: Unscrew the four-flange nuts with a wrench; remove the hub flange and side ring, then the wheel; replace with the spare wheel. You Can Lift Five Tons with This Hoist “ ALL right, back her up—little more.’’ With a rattling slide and a mighty roar, out falls the load of coal or stone. You’ve seen it done many a time where building operations are in progress, and have perhaps been rather interested to see such a big load so easily dumped. The chief requisites of a dump-cart hoist are strength, speed, power, lightness, and compact- ness. All these are embodied in the machine here shown. rigidly constructed of steel beams, yet it is not clumsy or unduly large. The power is produced by a train of spurs and bevel gears, and one man can easily lift five tons by means of it. The whole body can be inclined at from 30 to 50 degrees in less than two minutes. The manufacturers state that it occupies only eight inches of space behind the driver’s seat. is very Small, perhaps, but worth its The Rivaling Samson’s feat of old, this gearing makes every man a giant in strength 37 The whole job takes less than five minutes Transform your old car into a tractor and reduce the high cost of man hire stk in oad Automobile Turns Tractor TRACTOR conversion unit for large automobiles is in big de- mand by farmers who own cars of antiquated models. original front wheels, with the tires, are still used. Two steel disk wheels 48 in. in diameter are provided with internal gear rings. A 14-tooth spur pinion is secured to each end of the axle-shaft, after the rear wheels have been removed. Vibra- tion is taken up or a wood liner. Of course, provision is made for cooling, and numerous de- vices are kept in stock for each machine to be converted.

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The young lady is not acting careless with a rubber stamp or purposely addressing herself for shipment through the parcels post. She is ironing out wrinkles after washing her face Mon- day morning. The advantage of the treatment is that it is unnecessary to use a wringer or hang the face out to dry. The harness about the head pulls on two pieces of plaster and’ keeps the skin tight for easy manipulation Well may this young woman smile. She has read the circular that ac- companies the massage roller now engaged in removing her slight double chin, and she is therefore convinced that she will never have a wrinkle; never be obese; never have dandruff; never lack circula- tion; never have a thin neck; and never, never cease to be beautiful. She could be forgiven for laughing outright, or chuckling, or anything Trapped? No; this is not the Old Mill, but a new one which removes fleshiness while the pa- tient waits anxiously. It can be adjusted to remove weight from the ankles to the ears, and its purpose is to present exercise to those who are too tired to take it. With this device in the market no shape may be regarded as necessarily permanent 38 This woman is calmly watching a posse of nurses pursue her rheu- matism. It has been chased helter- skelter up her left arm, leaped across her shoulder-blades, coasted down her right arm, and will presently depart, due east, from her right thumb. Watch for it and avoid it. The machine administers heat with force and is exceedingly popular with the “ouch”? element Popular Science Monthly This Face Under New Management Giving you a peep at This woman stopped in of her own free will and deliberately asked to have this done. When the White Wings comb the machinery out of her hair she will have a permanent wave, and even the most caustic cynics will admit that she deserves it. If it wasn’t that a friend of hers lived through this she’d never expect to herself Niles aap Rha eba tin sR

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nt at July, 1919 the mechanics of beauty —We Would Rather Stay Homely win Rs 3 “te TRANSPARENT THIN MATERIAL HAIR EYELASHES7 This young woman is becoming beauti- ful, healthy, well built, and somewhat muscular by exercising at this angle and thus using muscles not usually called into play in the ordinary walks, jumps, and staggers of life. She is engaged in automatically preventing apoplexy, acid stomach, eye troubles, nose and throat ailments, and curvature of the spine. Small wonder that she busted the back off two chairs in order to follow the circular’s valuable advice Se ee a eee a ai maine i sat ADHESIVE When this woman came in here after a splendid night’s rest and a good breakfast, she looked somewhat drab. Now, after a tedious hour or more of steaming, rubbing, and semi-electrocution, her color is radiant and her expression both appreciative and alluring. Ain’t machinery wonderful? Can it do something for our chin? 39 The outstanding feature of this young woman’s peculiar type of beauty is that she has what might be termed fairly snappy _eyelashes. She felt that she needed them, and _ therefore bought them. They are fastened on with an adhesive substance, and according to the manu- facturer’s gossip can be removed only by blasting with dynamite With this simple nocturnal bonnet per- sons who have for years slept with their mouths open can at last bring the subject toaclose. With it one may foil the ills of adenoids, tonsils, and assure the good blood. resulting from proper breathing. Its sole mission is to keep the mouth shut, and there are thousands of instances in which it might well be used from sun-up to sun-down. All in favor say ‘‘aye” Nowadays they improve faces as thoughtlessly as they do real estate; but even now, for all we know, the patient may not be satisfied. Some folks are horribly particular

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What Is Ahead of Us? The world has received the greatest material set- back in its history. More people have perished, more property has been de- stroyed, than in any other period ten times as long OES peace offer opportunity? Will America do her best? When do trees grow most luxu- riantly, bud and shoot, leaf and bloom? It is in the spring, after the killing and destroying frosts of winter. When are wild animals thinnest? When do bears emerge, lean and gaunt, from their lairs? In the spring, after the exhausting and _ life-destroying winter. During the strain of winter both plants and animals have used up their surplus, and in the spring they must joyously and energetically hustle. When is man most hungry and when does he lay on flesh most rapidly? When he is recovering from an attack of wasting fever. Are these lessons to go unheeded? The Worst Setback in History The world has just received the greatest material setback in all the experience of history. More people have perished, more property has been destroyed, than in any other period ten times as long. Because there will be fewer people, the world will be relatively bigger than before. The sun’s warmth, the rain, the soil’s fertility, have not lessened. If human beings were trees or animals, they would recover with great rapid- ity; but we are human beings, and we may fail to realize that a new era has been born—born in travail, in agony, in blood, but nevertheless a great new era—and that it will take fifty years under wise leadership with best counsel and of greatest energy to catch up and to consolidate. By Harrington Emerson ARRINGTON EMERSON is an efficiency engineer who has done things. He put into operation some of the first long-distance mail routes in Alaska; reported on the coal deposits on the western American coast; and advised in regard to the northern sub- marine route to Asia. After he became a consulting expert in management he gained wide recognition on account of the success of his methods on the Santa Fé Railroad. He has advised many syndicates concerning industrial plants and mines in Mexico, the United States, and South America, and today is one of the best known men in his profession. Is there ground for sober optimism? Yes, if we hold on to our fine qualities, if we have broad and clear thinking leadership, if we have experieneed staffs, if we have intelligent, careful, energetic workers in the line. The finest words ever spoken as to organization were those so briefly and beautifully used by Marshal Foch when he was thanking General Per- shing. They contain all the truths that we must apply if we are to succeed in peace as we have succeeded in war. I shall paraphrase for the future what he said of the past: “Complete success will come only if all display fine qualities. We must have breadth and clearness of concep- tion in the leaders, we must have abilities and methods in the staffs, and we must have ceaseless energy and indomitable courage in the men in the line.” 40 Popular Science M onthly & The outlook is very favorable, the opportunity is there. America’s Wealth (1) It will take the world three to five years to build up the normal food supply. Because the United States is the greatest immediate purveyor of food (Russia being for the present too disorganized to count), the farmers will receive very high prices not only for grains, hogs, and cattle, but also for cotton. The farmers will want workers, and can pay the wages; and having sold for much they will buy much. Last year the farm products of the United States aggregated in value nearly $20,000,000,000. (2) But the farmers are only a group in the great class that creates supplies by annexing what nature has provided and what man desires. There are our mines, our forests, our fisheries, our waterfalls. Silver, copper, zinc, lead, iron, gas and oil and coal, cement, lumber, electrical horsepower, all are going to be in great demand. Gold alone has lost value. (8) Our products are going to be in demand because billions of property in Europe has been destroyed and must be replaced. They are going to be in demand because we ourselves at home have been falling behind. Owing to the war, we have curtailed our own improvements; they must now be brought up. ; (4) We are literally bursting with surplus values in the United States, and all the world needs these values. (5) One quarter of the world’s shipping has been destroyed. To

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a ae SS. a ee oe ee a a ee ae ae, ee ve eS SS eee eS OUTSellllUhTSe—Oe - Tienced July, 1919 recreate it will require materials, equipment, and workers. (6) Vast areas have been swept pare of all the accumulations of centuries of saving. All this must be productively replaced. (7) The existing industrial wastes in the United States amount to $50,000,000 a day. In a year this amounts to more than our total national debt. If we could save these wastes we could pay off the whole material cost of the war in two years. Happy is the nation whose income is so reatly above its needs that it can be curtailed $50,000,000 a day without reaching bed-rock. These, therefore, are the five stimu- lating conditions: food shortage, ship shortage, devastated areas, the great current wastes, the need for improve- ment and betterments. America’s physical conditions are ideal. If there is any misgiving it is due to what lies within us, not without. We are wasteful. In the last four years we have indulged in an orgy of waste. It will be difficult to stop it. We are provincial. We shall perhaps not know how to finance our sales. Wise Men Take Chances One American had the big idea. France wanted to buy of him, but had no money. His friends tried to dis- suade him from taking French bonds. They feared that Germany would win; they feared that, even if France won, she could not pay. “French bonds are good enough for me,” he said, ‘‘and if France loses I would lose both bonds and freedom. But if France wins yet cannot pay, I shall only be back to shirt-sleeves, where I started.”’ If we are wise we shall take a chance. Take French and other bonds of every kind guaranteed or at least certified to by the respec- tive governments, en- dorsed or at least still further certified to by our Government—bonds_ac- cepted by banks and made day. legal investments for sav- ings funds, for insurance reserves, and for fiduciary investments. It is better to have some loss than to have the whole world stag- Do I counsel reckless- ness? No. We have un- fortunately been both con- ceited and reckless. Any tyro ought to know that “cost plus profit’? is no ' proper basis for manufac- turing. Our Government was warned but would not listen, and its inexpe- representatives wasted $3,000,000,000 on the cost plus profit in- Our daily industrial waste in the United States is es- timated to be $50,000,000 a day, somewhat less than the cost of the war per That would be $18,250,000,000 a year. Stacked up in $20 gold pieces on a base 100 pieces square and 10,000 to a layer, this imagination- baffling sum would reach to within thirty-four feet nate of the tip of tne Eiffel 4 tower, which rises 984 feet above the ground iquity. I counsel extreme hopeful- ness coupled with extreme caution. Wastefulness, provincialism, over- confidence, are the faults of youth. They are serious faults, but they are not utterly destructive, as were the German and the Russian faults. Autocracy is leadership without staff or line; bureaucracy is ability and methods without either leader- ship or line; Bolshevism is line without either leadership or ability. What we must have is the balanced combination of all. We have our minor problems. Our Government in President and Congress came nobly to the front. An immense army was raised and sent overseas, billions were secured and spent, the end in view was achieved. Nevertheless, there was inefficiency as monumental as the enthusiasm. Labor is uneasy. Some think that it can find a _ class solution without reference to high { ideals, without need of clear thinking A and broad concep- iy tions, without staff Le experience, wisdom, I one | and methods. The ent | fundamental as to ie a division of returns Ah: is that part goes to nih i leaders, part to staff, part to work- ers, part to those i Sn atte cen ee —— (ewer Ere Ete. ¢ eam ft who furnish the equipment, part to those who furnish the materials, and part to those who buy. No one class can demand or at- tempt to take an unfair share with- out stirring up a hornet’s nest. ye In return for wages, for materials, for equipment service, whether high or low, there should be a_ standard equivalent in output for the time used for the unit of material, for the equipment service, and each should receive the fair reward for his own contribution. Wages Follow Price of Food Wages have risen on account of the rise in the cost of food. Wages have always somewhat closely followed the price of food. In the State of New York from October, 1914, to October, 1918, wages on the average increased 81 per cent, but during the same period the cost of food increased only 73 percent. Clothing increased about 50 per cent, miscellaneous articles in- creased 40 per cent, rent increased from 15 to 20 per cent, and the cost of ‘service, from utility corpora- tions, is the same as before. But there has also been more employment, so that, in spite of the absentees in the war, wages increased 123 per cent. When food prices drop the world over, there may come also a drop in wages, although it ought to be possible to miti- gate this, if not wholly to prevent it, by the double remedy of waste elimination. To hold our first place in the world, either as big brother to 1 humanity or in competition, | we must produce at lowest unit | cost. If we have wise leadership, | competent counsel, rational i] line workers, we shall be able ,/ | to combine lowest unit cost | with highest wage rates per hour, greatest number em- A ployed ‘and reasonable num- ber of hours. But if wastes are not at- tacked, if methods are not improved, we will stagnate while others take the world’s markets, and then we must drop toward European stand- ss sai SS FEN ards of inefficiency and low- | priced labor. a Russia has been engulfed by Bolshevism; Germany has been ruined by autocratic bu- reaucracy. Even some of our Allies may have trouble. But I hope to see America lead in the new peace evolution of the world. We have done more in war than anyone expected we could. Let us continue to deserve the respect of the world by our peace activities. All the conditions are favorable. It is our op- portunity ! an eA Sy . WAS ~~

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“Sharp as a Razor” Popular Science M. onthly Means Nothing to a Snail One snail has crossed the sharp edge in safety, but the others are making a “‘snail’s progress” SNAIL may not be a very rapid animal, but he can walk along the business edge of a razor-blade without cutting his feet. But it you want to see the trick done you must load. up a supply of patience. Here’s what Dr. Edward F. Bigelow, who, at the suggestion of the editor, took the pictures for the POPULAR SCIENCE MONTHLY says about it: “The snails will not crawl when one handles them, nor will they crawl much in sunlight; and, of course, it is difficult to take a photograph of a moving snail in the shade. The snails cannot be placed on a razor edge, for the moment they are touched they pull into their shell or if they do not the razor cuts them. To do the trick safely, they must go on voluntarily. “So I placed a ruler about a quarter of an inch from the edge of the razor, put the snails on the ruler, and found that they would crawl off over to the razor. ‘‘The snail seems to have no difficulty whatever in crawling even lengthwise on the razor edge if undisturbed. If Just after the start. ruler, while two others are reaching over the razor-blade Two of the snails are still on the touched in the slightest he quits and tumbles off. However, it is very inter- esting to see the snails crawl over the top and alongside the razor, provided one is willing to wait and wait and wait for his snailship to do the traveling. The snail, you know, travels only occasionally.”’ Other observers who have watched the snail do this trick say that he accomplishes it safely by clinging to one side of the blade with his walking surface, extending his fore part and bending it down over the other side. He is threshing out fir-tree cones, in order to send the seeds to an experiment station “Better Babies” for Trees UGENICS enthusiasts have lately turned their efforts toward the unprotesting trees. The Douglas fir tree has been selected for experimentation by Forest Service departments both here and in Europe. Cones have been gathered from old firs, young ones; sound firs, diseased firs; trees growing in the open, trees growing close to- gether; trees growing on high ground, on low ground; in cold places, in warm ones. The cones, or sometimes just the seeds, are then sent to experiment stations, where the seeds are labeled. pianted, and watched. A study of two-year-old seedlings points toward the following rules: Seeds should be planted in a warmer climate than that in which they grew; seeds from trees which grew in the open develop into larger, healthier saplings than those from dense-growth trees; the younger the tree and the richer the soil, the better the seed; seeds should not be planted in very high places. Cod Might Crowd the Ocean “TF all the eggs of a seventy-five-pound cod should hatch and grow to maturity, the ocean would soon become packed solid with codfish.”” There is, however, a loss owing to the peculiar manner in which the eggs are laid, the dangers which they must encounter, the fact that many of them are never fertilized, while great numbers are thrown on the shore by the waves. The greatest loss is in the vast numbers eaten by fishes, birds, and invertebrates. The ovaries of a twenty-pound cod have been computed to contain 2,700,000 eggs, and a seventy-five-pound cod, 79,100,000 eggs. In view of the fact that the eggs are eaten by an in- numerable host of animals, the codfish turns the tables by eating almost every thinkable thing. The list of articles found in cods’ stomachs includes shells, oil-cans, finger-rings, stones, corn-cobs, rubber balls, and every conceivable kind of mollusk and crustacean. At this stage in his career—he is only three days old—a cod may have several million brothers 42 trendy

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> ir SSS 6h oo = YY ( mamOoeo cd - Of aa July, 1919 Less Speed and Power or Better Roads—Which? By J. E. Pennybacker PEED, power, and capacity are . fundamental qualities of the motor-truck. Without them it would fail in its mission as a useful servant of man. ‘The same reasoning applies to the development and use of the huge freight locomotives on our rail- roads; but in the case of the loco- motive there is a coordinated develop- ment of rail and tie and ballast. The railroad man understands the folly of running a mogul engine on a light- pallasted forty-pound rail; for he knows that the outcome would be disastrous to the railway, the rolling stock, and the rail revenues. Further- more, the railroad man doesn’t use mogul engines on the entire system, nor does he lay hundred-pound rails on the entire system. He figures it all out from the standpoint of traf- fic needs and earnings. He has not hindered the full development of the locomotive by this coordination. Rather, he has fostered the develop- ment by holding it to economic lines. Why not apply the same policy to the motor-truck, and seek by a co- ordination of truck, highway, and traffic to make use of the speed, power, and capacity of the truck along sound economic lines? Few Existing Highways Adequate It is self-evident that exceedingly few existing highways can long sustain the heavy trucks now in use. Recon- struction of the highways means wid- ening of the surface, lengthening of the radii of curves, thickening of the road crust, and in some cases the replacing of bridges. For a long time the stand- ard width of road surface or crust on country highways has been sixteen feet. Now, the width of the largest trucks If it were not for good roads the automobile truck would have to be re- tired in favor of mule-power is frequently eight feet. Manifestly, therefore, a heavy trucking highway must have an absolute minimum width of surface of eighteen feet and pref- erably twenty feet. Wide curves are often obtained only at great cost, but safety of life and limb on heavily trav- eled motor highways demands them. Need for Thicker Road Crusts The road crust must be very much thicker than would be required for light motor-truck and general traffic. ee aes Little bumps to dangerous hollows grow. The remedy is to make the road crust thicker This is required by reason of the tremendously increased shear, pres- sure, and impact of the heavy trucks. . Making the tire wider as the weight of the truck increases doesn’t entirely solve the trouble, for the reason that as tire widths, whether they be four or fourteen inches, are relatively small as compared with the width of the pavement, it may fairly be assumed that the truck weight is concentrated on the entire road crust as a slab to support it if the type of construction be monolithic in character. That the shearing effect of the motor-truck on the road crust in- creases at a greater ratio than the weight may be shown by the follow- ing example. Explanation of Shearing Effect Assuming two thirds of the weight of the truck on the rear axle, and that a constant weight on the tire is de- sired, it would require four-inch width tires for a five-ton truck and thirteen- inch width tires when gross weight of truck and load is fifteen tons. The contact of the tire with the pavement would then form a rectangle whose perimeter would be twelve inches for the five-ton truck and thirty inches when gross weight of truck and load is fifteen tons. Thus, while the weight increases three times, the shear area increases only two and a half times, and the The miracle of mechanical ingenuity that is the modern automotive vehicle cannot be efficient on roads like this 43 Few existing highways can stand up under the punishment they get from heavy trucks. Shall we have less power or better roads?

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destructive effect is concentrated into a relatively smaller space. As the effect of the heavy truck extends through the road crust to the sub-grade, the crust should be so de- signed as to distribute the concentrated load of the truck to keep within the bearing power of the sub-grade. It is generally held that the pressure of the weight is transmitted through the road crust at an angle of forty-five degrees in the various types of crushed stone and gravel crusts. The wheel load of eight hundred pounds per inch width of tire delivered by a four-inch tire on a five- ton truck would be dis- tributed over an area sub-grade of 192 square inches with a road crust 6 inches thick. A fifteen- ton load with thirteen- sure must be met by substantial thick- ening of the crust. This thickening is also necessary to withstand the de- structive effect of heavy impact which comes from the pounding of the heavy truck moving over inequalities and dropping from slight elevations. This action can further be neutralized Popular Science M onthly the railroads have done—pick out the heavy haulage routes, and form a sys- tem plainly designated under law and regulation, marked and posted ag to class, weight, and speed, so that “he who runs may read”; and then, as rapidly as these heavy trucking routes are laid out, make provision to build them to stand the heaviest weight and the greatest speed found by truck- users to be really econom- ical. Keep the heavy trucks off the light traf- fic roads—there’s nothing to be gained by ruining the road and stalling the truck. In designing the high- way, this important con- sideration must not be overlooked—that, where- as the railroad can take up its light rails and inch tires would be sup- ported by 308 square inches of the sub-grade, or a little over one and a half times the area supporting the five- ton truck. Thus, while the weight is increased three times, the bearing area of the sub-grade is increased only one and a half times. Certain types of crust may serve to vary the angle of pressure, but the comparison of ratios of weight and pressure would not thereby be changed. These problems of shear and pres- Got a Match? EXT time you “‘light up,” think of this: About 10,000 matches are scratched in this country every second that passes, and of these 95 per cent are used by smokers to fire pipe, cigar, or cigarette. The man whose head for figures turned out that information also estimates that the time lost by the smokers in lighting matches—not in smoking—is worth $513,024 each eight- hour working day. He arrives at his estimate by figuring that it takes fifteen seconds to scratch a match and use the light, and that 213,759 men whose time is worth thirty cents an hour are holding matches at the same time, thus losing golden minutes at the rate of $1,068 a minute, or $64,128 an hour. No one, so far as we can learn, has figured out how large a percentage of the match-scratchers throw away the matches while they are still burning; but it has been estimated that a half of the fires which cost the United States $250,000,000 a year are caused by carelessness. Wood, phosphorus, chlorate of pot- ash, rosin, whiting, and powdered flint are the makings of this little device. If two trucks met here, one would have to leave the road. The minimum road crust should be from eighteen to twenty inches and wider curves must replace sharp ones by providing a smooth surface, but again this increases cost. For the purposes of heavy trucking a highway will cost probably double that of a light traffic highway. Now, if the truck is not to be hampered in the development of its usefulness, and if the cost of the highway runs well up into the tens of thousands of dol- lars, what’s the answer? Why, do as substitute heavier ones, strengthening the high- way is a much more seri- ous matter. The new heavy truck routes should be designed to sustain a known gross weight, of a known distribution, known dimensions, and definite speed limit. The justifiable limits, according to the best advice, may be put at gross weight twenty-eight thousand pounds, weight per inch width of tire eight hundred, width over all eight feet, height twelve feet, speed fifteen miles on solid tires and twenty-five miles on giant pneumatics. What Ho! The Land Canoe HIS inventor, John Queen Slye, must have been a brother to the little girl who asked that im- mortal ques- tion, ‘‘Mother, may I go out to swim?’’ for when he de- joororrritsey cided to invent STEERING GLARE he reasoned as that mother: did. He built a first - class canoe and then put it on wheels. The excuse he offers is exercise. A canoe on water is easily steered and moved, so that paddling develops grace but not muscles. But when you put your weight and the canoe’s on four wheels and then try to move, grace ceases to figure and muscles begin. The steering and moving mechanism is much like that of a tricycle, handle- bars above and pedals below. But in this wheeled canoe their functions are reversed. You steer with your feet and move by working the handle- bars back and forth. Your feet fit into shoes that are connected by ex- tension rods to the front shaft. By 44 aN a He gets all the fun of paddling his canoe without the danger of a drenching moving your feet back and forth in opposite directions, you steer. By moving the handles, the shafts to which they are attached are rocked. This movement is imparted to the gears and so on to the rear axle. The front end of the canoe is loosely connected to the mechanism, so that it moves up and down as if passing over waves instead of over sidewalk. The seat moves, too, as the rower works. With all these movements by him and the canoe he is sure to be well exercised. Of course if he prefers to take his exercise this way, that. is his affair. As for us, we prefer tennis.

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ly July, 1919 re Exchanging Mail-Bags ‘d on the Fly - S you stand on the railway ag platform, waiting for your es train, an express train flies by. ld Suddenly a man standing in front st of you ducks, and something st whizzes past your head and lands Ie in a puddle six feet away. It is =) a bag of mail. As the station vy agent drags the dirty, heavy bag af away, you thank the god of chance ng for your narrow escape and won- ng der doubtfully if that method of he delivery is the best. — ; The Southern Pacific Railway ‘h- has been wondering about it for au a long time, and has lately decided a to try out a new method. At each re- station a cement stand has been ke puilt near the tracks. On top of af this stand are mounted a pair of eg curved arms with horn-like ends. PK Just beneath the place where they i cross there is a straight arm with oad a ring attached to its end. The ild outgoing bag of mail is hung on 08s this ring. _ wn The train approaches at the Nit rate of fifty miles an hour. Out en from its side hangs a mail-bag. ht This bag is to be exchanged for the cht one hanging on thestand. As the od bags near each other, a hook lod extending out from the mail-car ind | een —— rf: “A —_ un ‘Tie eenaeeiens = ae ole an cs aden ie ae rat it yon the ics. png aig eb in am . mail-bags away. The aviator then 7 up the cable and hoists the bags on board ] floor of the car. . : | At the same time, the horn on Mail Your Letters in the Ocean the stand passes through the ring BO pinay : on the car to which the car’s mail- RE you annoyed at the very poor rush them to port at the rate of sixty bag is attached. Off come the mail service we are getting now? miles an hour. That is the Navy’s ring and bag, swinging around on Then join the Navy. Write your latest plan and it has been tried out the horn. The horns turn up at letters on board ship, and a seaplane successfully. an angle and so absorb the shock. will come along, grab them up, and The mail is collected and put into two sixty-pound waterproof bags, and the bags are then tied to- VA gether with a fifty-foot rope. Two ((- rowboats—each having a ten-foot i : mast—are stationed in the water about thirty feet apart. The rope ™ ] — is stretched across the masts, and ng fits into notches in their tops. he Ten feet of rope, with the mail- ng bag on the end, hangs down into te each rowboat. ; < By The aviator flies over, trailing be behind him a rubber cable with a od. 4 four-pronged grappling-iron on ine the end. The grappling-iron clutches the rope between the sely rowboats, and drags it and the tr bagsaway. Thecableis attached ing to a drum, and so the aviator a simply winds the drum to hoist oan the bags on board. ; vied ' As we see opposite the railroads . poy a Pi a. too are trying their best to im- | he (Right) The mail-bags have just changed places. The bag that hung on th a a this the stand is now entering the fast-moving train ; the bag from the train is will add its help to the Navy and us, swinging around the arm of the stand. (Left) As the bag swings around the railroads, the Post Office will one arm the arms turn up at an angle and so absorb much of the shock simply have to improve. 45

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Machines that Rebuild Men How science is solving the _human reconstruction problem One leg is better than none; but when the re- construction experts at the Letterman General Hospital in San Francisco ‘ Popular Science Monthly ue are through with this soldier, he’ll have an arti- ficial mate for the surviv- ing member of the original pair that will doeverything except react to a pin-prick fe #s Not a diver’s dress of a new kind, but the latest thing in ultra- violet lamps. The ultra-violet rays in the sun are what cause sun- burn. The patient here will have an artificially sunburnt scalp; his circulation will be stimulated. The man on the table is trying the effect of electricity on benumbed muscles with excellent results i“ Notice how large a part elec- tricity plays in the work of reconstruction. Electric heat softens stiff, inflamed joints Giving the water cure to a man whose nerves are war-wrecked. The patient remains in the bath for hours at a time. His attendant is taking the temperature of this strange bed Queer little cells that receive the patient’s body and leave his head outside. It’s the electric-bath part of the great system of rebuilding those men that war hes wrecked 46

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July, 1919 Everybody Works but Father These various “‘Lindys” are really not so sweet as the sugar-cane by f which they are surrounded. But 7 the fault lies in their heavy jobs. i They cut down the cane with ma- a acco chetes, stack it on wagons, take it to aa the windmill in the rear, and then squeeze the juice out between rollers Sa t PROWEE SUN War did not create conductorettes. The woman above has been collecting fares on a Chilean trolley car for many years. Each time she collects a fare she tears off a receipt from the roll around her waist and gives it to the passen- ger. Later she takes up receipts and collects another round of fares Do you drink cocoa? Then you will be interested to know that these very women may have done a barefoot dance on some of the cocoa beans from which your cocoa wasmade! They dance the coating off the bean and make it smooth and shiny “Frailty, thy name _ is woman!’ So said Shakes- peare. It is quite evident from the picture to the right that Shakespeare never paid a visit to the Philippine Islands Photographs © Brown & Dawson 47 Servants in the house? No, in the street. These barefoot women are street-cleaners in San Domingo, who gather up the dirt with brooms made of branches tied to sticks. They consider them- selves quite fortunate in getting such easy jobs, for the women of the West Indies do all the heavy work This place is Trinidad, the island whence asphalt comes, and these women are natives. What are they doing? Only coaling a ship. They go to the coal-yards with their pans, fill the pans with coal, and then carry them over to the ship The women of the Philip- pines are hard workers. When they do have a few spare moments to rest in they pick up large wooden mallets and hull rice for preparing food 1

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Building a Railway Bridge on a Boat ‘Popular Science Monthly - The tide rises and falls, but the train speeds along at an even level S you ride through Prairie du Chien, Wisconsin, you hear your fellow passengers talking about the pontoon bridge you soon will cross. At the word “pontoon” you auto- matically mumble something about Xerxes crossing the Hellespont and try to remember what you once learned about that pontoon bridge he used. A pontoon bridge is a bridge built on boats, rather shaky and dangerous—a de- gree better than noth- ing in an emergency. It is often made simply of planks laid across rowboats which are placed side by side. While in alarm you wi imagine your train swaying and finally falling off into the river, you find your- self already crossing the bridge. No jerks, no wabbling, nothing unusual about it! How can that be? This pontoon is so built that tide variation, and the change of buoyancy due to the weight of the train, are absorbed in its mechanism. Instead of being made up of several boats, it is built in one. The pontoon is a double- decker. On the lower floor is the steam engine, with its drum, that opens and closes the bridge. This is done by means of a heavy steel cable which connects the west end of the pontoon with piling in the river. Between the lower and the upper floors there are nineteen columns, af ee ATLA By P. Schwarzbach each of which contains twenty-eight blocks seven inches thick. The tracks are on the upper floor. As the tide rises some of the blocks in each column ‘are gradually removed by hand. The space between floors is thus shortened SIE +“ % This pontoon bridge, when finished, will have two floors: an upper floor, to hold the railroad tracks, and a lower floor, to carry the mechanism that will keep the pontoon in a constant position just enough to make up for the tide rise. The blocks are put back when the tide goes down. This operation keeps the level of the tracks above constant. The number of blocks taken out during each tide rise depends, of course, on the kind of tide; the greatest number are taken out at flood tide. When the blocks are taken out, six motors on the lower deck, which are run by a turbine-driven dynamo, turn drums that stand beside all the columns of blocking. Wire cables attached to these drumis extend up and over pulleys which are mounted on beams on the upper floor. As the drums turn, the cables lift up the tracking and keep it up until the blocks have been removed, Thenthe cables are un- wound and the track- ing slips back into’ place. The tracks on the .pontoon are nine inches higher than the tracks on the pile bridges on either side to which they are hinged. This allows for the sinking of the pontoon when a heavy train crosses it. The tracks approaching the pontoon bridge have a downward incline of nine inches to make transition smooth. The boat itself is 274 feet long, 56 feet wide, and 6 feet thick. The wood in it was treated with many tons of cre- osote to keep it from rotting. This pontoon is opened only for very large boats. All small ones must go through spans in the pile bridge built at the east end of the pontoon. From Prairie du Chien this bridge goes over the Mississipi to Iowa. You may think it a clumsy way to build a bridge; but the Chicago, Milwaukee & St. Paul Railway does not agree with you, for it is building many bridges — after this pattern. This man has pulled blocks out of pontoon bridges for thirty- five years; the blocks are taken out to allow for the tide rise 48 The tracks are raised by drums and cables when it is time for blocks to be taken out; this takes the weight off the tops of the columns — —

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‘urn the bleg up ited the the ocks ved, -un- ack- into’ the ine | the pile side are lows the Davy The y the have cline nake if is feet »d in cre- This large ough ; the ridge You ild a ukee with idges _ ycks mns July, 1919 ase _ a Up the Incline, Over the Tin Down to the Wood-Pile HEN you “dip the dip” on a scenic railway, you are first carried slowly up an inclined track to the top, and then you are unceremoni- ously dropped. That is just the sort of treatment these logs are getting. They have come on freight-trains to the paper-mill, and they are being un- loaded. A man at the bottom of the inclined truss takes the logs from the cars and puts them in a trough, where an endless-chain carries them up the incline. When the logs reach the top of the truss they drop off and make a huge wood-pile at the back door of the mill. The back door is opened, and the logs are taken in, turned into wood-pulp, and later into paper. Getting In ERE’S one way of making hay while the sun shines which neces- sitates no pitchforks, elbow grease, and sunburn. The hay-rack has a revolvable circular body which is connected by a series of pulleys to the hub of one of the wheels. Then, when the wagon moves and the wheels go round, the body re- volves. Trailing behind the wagon is an endless-chain conveyor having up- right and crosswise slats. The crosswise ones do the moving. The logs are taken from the cars to the trough, and moved by an endless-chain arrangement up the incline This log-stacker, as it is called, is mounted on wheels that fit on three rails. One wheel is near the bottom of the truss, and the tracks on which the other two rest are thirty feet away, near the raised end. This makes the log-stacker, though large, movable. The single .wheel, sixteen feet beyond the bottom end, is enclosed ina heavy concrete counter-weight which keeps .the truss from toppling over. The endless chain on the incline is run by a twenty- horsepower motor. On this chain there are projections every four feet to keep the logs from slipping back- ward. the Hay The hay is scooped up between them and rides up to the top, whereupon it falls off into the wagon. Thus the hay loading goes on automatically. The hay-rack has a revolvable circilar body which is connected by a series of pulleys to the hub - of one of the ground wheels The hay is scooped up between the slats and is carried up to the top of the loader where- upon it falls off into the wagon 49 With this tray hang- ing around his neck, the berry-picker can use both hands off and make a pile against the door of the paper-mill Gather Ye Strawberries ina Tray TRAWBER- RIES, dew - berries, blackber- ries, must all be gathered by hand —usually one hand, for the picker needs his other one to hold the berry tray. If he could pick with both hands he’d do twice as much work. But what shall he do with his tray? Hang it around his neck, just as the man in our illustration has done. The tray fits in a holder that hangs by means of a rope around the picker’s neck. As he leans over to pick, the tray swings forward and he drops the berries into it. ‘When his tray is full he takes it out, places it on the ground, picks up an empty one, and goes on with his work. Boys run up and down, supply- ing the men with empties and rushing away with full ones. When berries are harvested in great quantities for canneries, evaporators, or juice factories, the work must be done rapidly, so that all the berries will be in the same stage of development. For instance, the berries used in evaporators must be very ripe before they are picked. If the picking were done slowly, many of them would ferment and become useless.

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The combination speedometer and clock helps simplify the dash- board. The clock is wound mechani- cally by the speedometer shaft Right—tThe full box-car height is utilized by simple metal stanch- ions which permit the loading of two trucks in place of one The unusual form of open tread ‘on this tractor wheel gives greater traction and is self cleaning. The three- piece band may be re- moved in about ten minutes \ N ' : N NY N N ‘ ; 2 f N N = N i > | i AY 3 y a AAA ARVANA AAA NAAM AIT The small truck chassis tilted at an angle inside the lighted interior of the large show truck allows a first-hand examination by prospective buyers SSS SSS & we gecoctae 5 . PAB WWW BNW DWwq7 RAM. WANN WWVIW IPH Ds SWWWOW A N N ET dda New Accessories that Keep SLA Ladd DEBT BR RD DW WWwWwwWwww BEF" FBX WWOVN \ ? co ee = ‘ ee SS WW A wash-boiler, a short length of rubber tubing, and water are all that is necessary to flush the truck’s storage battery, provided the body floor has a trap-door LAMM LULL LL ALL lf aL ZZ USED PART OF CAPSULE - im PAPER CAPSULE GREASE ~ SHAFT > BEARING ; \, .* 4 ee gash. ee A paper capsule full of grease is set into the grease-cup, eliminating dirty hands and clothing GEE ccc ikiiGG05n50u5uquq13uu0..Pcccdmmunmupuddddddidussuussse g SSSI AAAS AAAS ASS SSSNIA! SWRAAAMWW, Its low-built body dumps the load by gravity, which is an advantage over old-time body methods 50

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Down Automobile Truck Expenses AW

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The steam washing-machine pictured A new type of truck body which dumps FERRULE _w above cuts expenses by cleaning dirty and and piles bricks at one and the same SOUND OUTLET oily waste. Where there are a large num- time requires only two men, thus con- ber of cars this device is a real money-saver serving man power to a decided degree VIBRATOR TYPE ELECTRIC HORN Enclosed in -the lamp shell, the horn is protected from “ dirt and oil and is out of the i; SS way at alltimes. The mech- * yo ‘

DAMP AIR TO a a a anism of the lamp may be of SCREENS sey any type. With the vibra- r : tor type of electric horn the wires are threaded through the tubular member and its regular supporting posts with the lighting leads, no outside wires being required SANE ba Left—With its little roller Ce P| platform, the oil-barrel is Sig | rolled where it is needed. ' ee | When not in use it is kept in a . : Vii 5 ie ; , box which covers it from sight This contrivance cleanses and : Ghee ve moistens the air on its way to “ the cylinders, which helps keep them at their maximum efficiency Se a — $ rT TT akcacsccacaauaaacaddsautica

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An enterprising garage-owner pro- vided his men with a clothes- SS . NOON NMWVO WH AA

This truck body is so divided into compartments that it measures the concrete or wringer to dry the wet chamois other building material and dumps the desired amount on the construction site cloths used in washing the truck 51

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Popular Science Monthly Not a horse will be used on this 200,000-acre wheat farm, which is being worked by a corporation capital- ized at $2,000,000. Fifty-two tractors have been purchased, and their plowing record is an acre a minute HEAT will be harvested next fall from one of the world’s largest farms, compris- ing about 200,000 acres of Indian lands in Montana and Wyoming. The land is located on the Crow, Black- feet, and Fort Peck reservations in Montana and Wyoming. To make this land productive, a corporation with a capital of $2,000,000 has been organized. On this huge farm not a horse will be used. Fifty-two tractors are now The Biggest Wheat Farm in the World the property of the corporation, and the plowing record for last summer was more than an acre a minute for the working time. Each harvester will handle twenty- five acres a day, and enough harvest- ers will be put on each 5,000-acre unit to do the work in ten days. Forty-five days will be allowed for the plowing. Seeding will be figured in In the last dozen years the Govern- ment has laid out irrigation projects along the river bot- toms in a number of reservations. Many of these systems have been com- pleted. When the enterprise is fully de- veloped it is expected that their irri- gated lands will raise a crop every year, while the dry lands will raise a crop every two years. The average annual rainfall in Montana is only the same way. fifteen inches. The Pushmobile that Will Never Stall E doesn’t know anything about ‘‘dead centers’ —the little boy in the picture below—but he does know that he likes his new pushmobile better than his old one; for his old one often stopped short when he was moving slowly, refusing to go until he got out and gave it a push. His new one never does this, for it can’t get in a dead-center position. With every com- plete pull of the handle the gears turn a little more than half a cycle. This keeps them from getting on dead center, no matter how slowly the machine may be moving. The dumping cart on the back of the machine is a new idea in pushmobiles. All boys—even those who wear socks and patent-leather shoes—love to cart loads of dirt to far-away places and dump them. The boy need only turn round and give the cart a push, and the dirt will pour out freely and easily. Though it is called a swing, it is really a sec- . tion of a loop-the-loop 4 iS aa A Slice of Scenic Railway HE father of this invention called it a “‘swing,’’ but it is really a car that runs up and down on curved tracks, giving to its occupants the sickening feeling No fear of this car stop- ping on dead center when the boy dumps his load associated with swings. The tracks terminate rather abruptly, so that if the passengers get too frisky they are apt to topple out when the car hits the high spots. The car seats two people, one at each end, facing each other. They have in common a handle which they mutually grasp when they want to start rocking. By straining backward and forward they set the car in motion. Gravity and momentum keep it going. The car is guarded so that it won’t get off the track. This is done by a second set of tracks just above the wheels. These two sets of tracks connect at their ends, so that the wheels won’t slip out between them, thus preventing the car from plunging into space. The tracks are supported by curved beams, and both tracks and beams are fastened to wooden supports. 52

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July, 1919 | | ° Tying Knots in Endless Ropes A very old trick of the fake “mediums” exposed

By Hereward Carrington

HORUS girls have worked out a single sentence which bursts with philosophy. Here is that summation of stage experience: “The smarter they are, the quicker they fall.” In- elegant and ungrammatical, to besure, put the truth. Johann Karl Friedrich Zollner, in the foremost ranks of Germany’s astronomers and physicists, watching a simple sleight-of-hand performance in which knotted ropes figured, was In all of his rope tricks Slade depended upon that lone principle of the sleight-of- hand expert—that the hand is quicker than the eye. The simple beauty of all Slade’s tricks is the ease with which an amateur can acquire them. To perform the first one, a piece of rope a yard long is prepared be- forehand in the following

“ ~ entranced. ZoOllner, who was clever manner. A number of knots rn- enough to discover, among other are tied in the piece of rope, : = things, that the sun is five hundred and the ends are knotted tee. and seventy thousand times more together. The rope is then After tying the ends of a 30-foot rope to the wrists . prilliant than the moon, wasted hour tucked up the sleeve, with of two spectators, the medium makes loops in the 7 after hour, studying the actions of the knotted end just in- pe gg of the rope — them — head of ry de- Slade, whose chief claim to greatness side the cuff. The magician There oe pr Mego et oe ee send Rae was his ability to hide knotted ropes or spiritualistic ‘‘medium, a up his sleeve! now prepared, shows the spectator them, and conceals the knot in the “— another piece of rope a yard long. palm of the hand. He works down - ° The Hand Quicker than the Eye He places the two ends together, ties the knotted ends inside his cuff, and fe these he seals to the table; or he —, Zollner was “‘buffaloed.’’ Apparent- merely seals them together. The ly Slade was able to tie knots in end- : Y lights are turned out; he puts the less cords without the slightest diffi- rope he has shown to the spectator call culty. Zollner thought that Slade into an inside pocket of his coat, accomplished the feat by resorting pulls the rest of the concealed rope rs” to some mysterious use of the fourth from his sleeve. loes dimension, or by invoking some his spiritual aid. Time after time, Tying Knots in the Light 1 he the Professor sat watching Slade, and fascinated, spell-bound, trying to There is also a way to tie knots r it figure out in his mighty brain how with the lights on. One end of the om- that impossible trick of tying knots rope is held in the right hand about han in endless cords could be achieved. one foot from the end, and the rest lead And he died believing that Slade of the rope is wrapped around the be tied knots by some practical applica- right hand until allthe ropehas been ; tion of the obscure fourth dimen- 3 wound. The first end is then drawn wo sion. — <a r 6 a ig through the loops, tied tothe other who Now that the hoax is history, the oe See OS ee: ee end, and sealed. When the coils are ads childish simplicity of Slade’s tricks gage ——— paiew? 3 = taken form the hand there will be as pie is given to the public to smile over. hidden rope may be substituted many. knots as there were loops. an

To tie knots in the light one end of the rope is held in the right hand and loops passed over the fingers, after which the two ends are tied and sealed. The manner in which the loops are made isan important detail in performing the trick 53

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Popular Science Monthly It is called a milker’s mask, though it does not protect you from milk but from the whacks of a cow’s tail The Masked Milker OU are milking a cow. A fly bites her and she switches her tail around to chase it; but instead she unwittingly hits you in the eye. You grow angry and sit on her tail, whereupon she grows angry and kicks. Over goes the pail, out pours the milk—a day’s labor lost— tragedy ! Frederick W. Elleby, of California, has been a sufferer for years. Many the lost pails of milk and the black eyes his cows’ tails have caused him. The result? He has invented a face-mask for milkers. Catchers and fencers have them, so why not milkers? The mask fits over your face, under your chin, and fastens behind your head with a strap. Heat rises from the lamp, up the funnel, up the tubes, into the boots, and dries them in a nice, gentle way When Boots Are Wet N October 1, 1918, William Preston Grace patented a “device for drying rubber boots.”’ Whereupon winter decided perversely to be mild and snowless so that nobody would want rubber boots or driers for them. But it will not e’er be so and Mr. Grace’s drier will come into its own. A funnel-shaped stand of tin is mounted on three legs, The top of the stand runs into two upright hollow tubes which are as long as the average rubber boot. Screening is spread across the ends of the tubes and then wire crowns are mounted on them. The boots are hung on the crowns and the stand is placed over a lamp or oil-stove. The heat rises up the tubes and dries the boots, but will not burn them. The Horn Is Telephone Operator i in the Forest ne agg walking through the forest smelled smoke clouds rising. A fire! He rushed to the nearest telephone line, attached his telephone, and rang. Noanswer. The men at the station -had walked off and did not hear the bell. In the ranger’s telephone there was a klaxon horn. He connected it up and started it whirring. The noise echoed through the forest, and in a few moments a voice came over the wire. Help was sent and the fire was put out before it had gained any headway. This combination telephone and _ signal horn is the invention of C. M. Allen of the U. S. Forest Service. It is made so com- pactly that it fits in a box which the ranger can carry with ease. On the bot- tom shelf of the box are six cells of dry batteries which furnish the power. On the top shelf are found the transmitter and receiver and on the middle shelf the horn. A special magneto furnishes either direct In the box are: top shelf, the transmitter and receiver; middle shelf, the horn; bottom shelf, six dry-battery cells The ranger calls his party by means of a klax- on horn. instrument is carried easily or alternating current. The alternating current is used for the ordinary ringing signal and the di- rect current is used for operating the horn. The box complete weighs thirty pounds. Somehow we cannot conceive of this valuable invention being wasted wholly on the forestry service and its fires. For instance, we know of innumerable apartment houses and office buildings where it could be installed with profit. Imagine being able to turn on a klaxon horn down on the first floor when the elevator boy won’t come up! Or being able to send a shriek- ing call reverberating through the halls when the telephone girl goes away from her board and will not come back. You'd have everybody running—from_ the house __ superintend- ent tothe janitor. A little service, James, please—a little serv- ice! And, James, next time we don’t get service we’re going to connect the electric lighting mains to that horn, and let it sound all forenoon. The

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ly July, 1919 When the Table-Leaves Are Not in Use ABLE leaves are useful things to have when you feed a multitude of friends, but when your friends have gone the leaves once more become a nuisance. You want to hide them, put if you live in an apartment you can’t. Your only hiding-place is your cellar “‘bin,’’ and no padlock will hold itself responsible for the things that go in it; besides, table leaves would be cumbersome to get to and from the cellar on the dumb-waiter. A leaf closet is the best solution of this problem. Its picture is shown here. It is built in such an .incon- spicuous place that it might easily be taken for part of the wall. After you put in the leaves you shut the door and forget all about them until the next momentous occasion ar- rives. The feathers are pulled out by rollers and then drawn into a vacuum tank = It used to take her the better part of an hour to do what this instrument does in a few minutes It Doesn’t Leave Even a Pin-Feather OTS of things happen to a chicken between the time it ‘clucks” around the barn-yard and , the moment when you chew on its a If og a _ all a tender leg. ies. cooking it the ody oP” pen eee ae chicken must be picked—heretofore will the leaves don’t fill may be shelved off to hold other unloved necessi- a long, tedious job, for a chicken me ties and household encumbrances. cei ators item gee wae wee ibes . Now O. G. Rieske has invented : ’ a picking-machine, which pulls the de. Baby s Cradle-Bath-Tub feathers out in bunches and whisks uel Your Shopping-Bag them into a vacuum tank. neal A six-pointed rake-like implement om. ERE is a new “ three-in-one’— raises the feathers so that they cradle, bath-tub, shopping-bag— touch a pair of rollers which revolve made out of poles, ropes, and a cre- by electricity.. The rollers pull the tonne bag. The object of all “three- Build a closet in your kitchen for feathers out between them and at in-ones”’ is efficiency. Observe! ° holding your idle table leaves pass them on to a tube which sucks > di- Your child is sleeping peacefully in them up into a tank. A small suc- orn. its cradle while you read the paper alongside. Suddenly tion fan helps the work along by disposing of the feathers. is, mee svet a bargain. ae rg your child out, take the this cradle from its stand, bend it into a shopping-bag, and ly on ag a —— _ — — back, rien it A The Modern Bean-Shooter out, pick your dirty chi rom the floor, open the bag, Di sy ; ~ A fill it with water, bathe your child, and then hang out the Ne Slings Toy Airplanes lings bath-tub to dry. OYS are con- ofit. This cradle is made of waterproof cre- stantly getting axon -¥ ») tonne so that it won’t leak when it is used themselves in the ‘~ >» as a bath-tub. The colors, of course, trouble by slinging von’t must be fast, for the sake of your child. stones at bald heads yeing : and window-panes. riek- If it is simply a de- iting sire to shoot that halls prompts them, the hone airplane slinger from shown here will ] not cause them as much ‘ou’d » pleasure and fewer ody spankings. the The monoplane is gliding back to The wings are -end- its starting-point—the boy’s sling made of fan-shaped a | tough paper, sup- mes, ported by light metal stays. They are folded up close to sionnini the body of the plane before the plane is placed in next its sling. When the boy shoots, the plane, with its wings get folded, flies high in the air. It sometimes reaches a height ng to of one .hundred feet. octric Not until it has reached the highest point in its flight do ) that as the wings open. Then a spring forces them out, and the ound You don’t need the poles wien you #6 shopping: and when plane glides gracefully to earth in wide spirals frequently ' there are no bargains, you might give your child a bath landing almost at the shooter’s feet. 55

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‘Popular Science Monthly * Healing Burns without Pics or Disfiguring Scars EMEMBER the excruciating pain which even a slight burn causes you, and then try to imagine the suffering resulting from _a severe burn by which a con- siderable area of skin is scorched and destroyed. Such severe burns occur sometimes in factories, foun- dries, and mines, and are classed among the most serious injuries to which workers are exposed. When the Ger- mans introduced “liquid fire’ as one of their weapons of at- tack during the great war, the Allied sur- geons in the field hospitals found it difficult to cope with the task of adequate- ly treating burns. At that critical moment Dr. Barthe .de Sandfort, a retired French Navy sur- geon, who had invented a Issy-les-M oulineaux, in Paris, to which all soldiers suffering from burns were sent for treatment. The results ob- tained from this treatment were so (Left) Before the protective wax coating is sprayed on the burned sur- face the scorched tissue is dried by an electric dryer (Right) The melt- ed paraffin com- pound, kept liquid by the hot water in the jacket of the atomizer, is sprayed on the burned surface and forms a protecting cover method of treating burns by coating the scorched surface with an air-tight covering of medicated paraffin wax, presented his invention to the French military authorities and offered his services in administering the treatment and teaching others the proper method of applying it. Hewas ‘given charge of a small hospital at A thin layer of cotton is placed over the paraffin coat- ing of the burned surface, and by painting melted wax it is to adhere to the coating employs for covering burned surfaces consists of neutral paraffin, resins, and certain disinfectants. It has a low melting-point, and, when heated to 140° or 150° F., forms an amber- colored liquid which is either brushed over the surface of the burn or sprayed on. The hot liquid hardens quickly, and forms a pliable yet air-tight cov- ering of the burned area. A - thin layer of cot- ton is placed on the first coating of wax, and ig made to adhere to it by painting it liberally with the melted wax. For further protec- tion the coated .part is swathed in cotton. After the first twenty-four hours the patient, in most cases, is free from pain. During the first stages of the healing process the it with made remarkable that it was adopted by the hospital staffs of all the other Allied armies. The compound that Dr. Sandfort When the dressing is to be changed it is ripped open with the scissors and it can then be peeled off without difficulty and without giv- ing the patient any pain injured tissues secrete a large quantity of lymph, which collects under the shell of the dressing and prevents it from adhering to the tissues. The wax dressing may easily be lifted or peeled off without causing the slightest pain to the patient. The burns should be dressed every twenty- four hours for the first week or so. Workshops that Travel on Wheels Workshop trains like this, compactly arranged and equipped with electric power and machinery, were used by the Allies behind the Flanders front URING the intensive military operations along the Flanders front it was a matter of the great- est importance to keep the enor- mous technical fighting apparatus, the wonderfully efficient war machinery, in good condition. Repairs were con- stantly needed, and time was too precious to permit the delay that would have been caused by long transporta- tion over difficult roads. The British War Office. supplied six completely equipped military workshop trains which~ were operated on the narrow- gage military railways behind the front. Each of these six trains consisted of six cars, including a generating car, two machine-shop cars, a tool van, a 56 stores van, and an officers’ car. The cars were all of the same dimensions, 17 feet 8 inches ‘long, 5 feet 5 inches wide, and a trifle more than 9 feet high. The generating car was equipped with two 15 to 20 horsepower gasoline engines directly coupled to 10-kilowatt generators. The machine-shop cars car- ried drills, lathes, shaping machines, etc.

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aceg and | low l to ber- juid ther * the the ryed hot lens and able COv- the cot- 1 on ting here ting lted tec- fter ours ses, ages the ea iph, the and ring wax be the The ity- so. The yns, feet ped line ratt -ar- etc. July, 1919 Can You Save a Drowning Man? ef ELP! I’m drowning!” You jump up at the cry, throw off your coat and vest, and dive in. Being a good swimmer, you are quite confi- dent that you can save a life. But live-saving is dangerous busi- ness. It is not sufficient to grab a drowning man with one hand and start swimming to shore with your other hand and your feet. If he is terror-stricken he will cling to you and pull you down with him. If you don’t hold his head above . water he will drown while you pull him behind you. So before you try rescue work you should learn how; for there is method in it. The Red Cross Society gives you your choice of two excellent methods. In one you lie on your back and swim with your feet. This leaves your hands free to hold the drowning man above water by the ears. You use the scissor kick of the sidestroke. In this stroke you draw your feet up close to your body, crossing them, and then kick down. This sharp kick propels you backward through the water. If the person you are saving knows how to swim and is not frightened you can use a much easier method. The victim floats on his back while you grasp either his right or left Lie on your back, kick with your feet, and hold the drowning man’s head out of the water with your hands If your victim is not frightened she will float if you help her with your elbow; then use the breast stroke arm, according to which side you swim on, and thrust your elbow under his back. This relieves him of much of the effort neces- sary in floating. You swim for- ward, using the breast stroke with your one unhampered arm. If the drowning person strug- gles dangerously it may be neces- sary to stun him in order to save both your lives. A New Use for Jack-Screws They were employed in setting straight a Chicago intake crib FTER the newest of Chicago’s intake cribs, off the foot of Wilson avenue, had been completed, it was found that the stone superstruc- ture was eighteen inches out of plumb. The ring-shaped superstructure, built of square-hewn blocks of granite, has an outside diameter of seventy feet at the top and ninety feet at the bottom, with an inner diameter of forty feet. It rests upon a double-walled steel caisson filled with concrete, which was sunk to the bottom of Lake Michigan to form the foundation of the crib. The uneven density of the clay bottom caused the caisson with its superstruc- ture—which alone weighs about 1,400 tons—to lean over. To bring both the superstructure and its foundation back to a vertical position was not feasible because the foundation did not rest upon bed-rock. It was decided, however, to tilt the superstructure to a vertical position. This was done, not by rebuilding the ring of stone masonry, but by blasting away the layer of concrete by which the superstructure was joined to the foundation, placing a large number of jack-screws between the foundation and the ring of masonry, and by means of these raising the superstructure on the overhanging side and lowering it on the opposite side until the whole structure was again in plumb. The concrete was blasted out by small charges of dynamite handled so skilfully that the masonry above was not hurt. To keep the waves from dashing in where the concrete had been removed, plank shutters, suspended by ropes, were placed over the open spaces. For leveling the superstructure three hun- dred jacks were used, which were man- ned by twelve experienced house-movers. Masonry underpinning was substituted for the jacks when the superstructure had been tilted to a vertical position. As the concrete ring between the caisson wall and the masonry was blasted out, jack-screws were placed in position and shielded from the waves by plank shutters The engineer on the platform in the middle of the structure directed the tilting operation by careful sighting with the ‘telescope of his leveling instrument

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. Popular Science Monthly for Our Daily Bread grains and be your own miller The Daily Grind You can buy your own “Time to get up,” you think, when you hear the grinding of a coffee-mill. But the particular coffee- mili shown here is not grinding the morning coffee. In fact, it isn’t grinding coffee at all: but wheat for bread. The thrifty housewife thereby saves the price of grind- ing and gets double serv- ice out of her coffee-mill A few years ago this mortar and pestle pounded out things in the back room of a drug store; now the mortar and pestle. have been transferred to the kitchen, where they are pounding out grain in- stead. Sufficient patience | and power in using them will result in reducing grain to a powder fine enough for bread-making By means of a meat-chopper the grains of wheat in the top picture were turned into whole-wheat flour for the food in the lower picture The principle of the tub and poles for pounding grain is the same as that of the mortar and pestle shown above, but the proportions are different. There, a large woman pounded with a small pole; here, small chil- dren pound with large poles. The children are Filipinos and they are pounding rice Surely the rolling stone in the picture above gathers no moss, though it may be gathering corn flour. Two firm brown hands are rolling it on another stone, and between the stones grains of corn are being crushed. The hands belong to a young Indian girl of New Mexico. Boys who long for a coun- try where they won’t have to go to school are recom- mended to parts of China This Chinese boy does not go to school, but he does have to spend several hours a day grinding corn

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ne in thers iy be Two olling and rains shed. oung *xiCO. July, 1919 Champion Dresses a Chicken in Twelve Seconds Clarence Hockings, the record-breaking chicken dresser, gives an exhibition of his speed and skill Mr. Hockings does not Then he ducks his chicken chop his chicken’s head in a pail of water in order ~ off; neither does he wring to wet the feathers, and its neck; he pulls the plucks them, first from the neck forward and _ slits left leg, second from the it with a sharp knife right, third from the left just below the ear lobe wing, and fourth the right Off with his head even though he is dead, and an old-fashioned chopper is used; then the legs are amputated just above the knees feet ready to be killed. The backbone is the next thing to go. The chicken is turned on its right side and held by the left wing. Then the knife is in- serted just in front of the collar- bone and is drawn straight back along the backbone on each side Clarence Hockings, the speed king at dressing chickens, catches his bird with a net and then takes it out by a ee Se t ; x takes the champion just ’ twelve seconds to dress a F ec chicken, only sixty being re- ? ea quired from barn-yard to oven Its final appearance will be in the dining-room under “Half a broiled chicken with dressing and green peas” _ id ean | | bind All the feathers he has The victorious handful gathered so far he uses follows the back fea- in a great push which thers into the pail, and forces all the feathers the dresser’s hands are on the chicken’s back to free to gather in the retreat ignominiously breast feathers and into the pail any left on the wings Hockings next grabs his chicken by the neck and pulls; out come neck, backbone, and all the entrails, completing the cleaning process The carcass is torn in pieces— two of them, to be exact; the breastbone is removed by a few deft motions—see Hock- ings for particulars—and the sixty seconds are nearly up

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Forty-nine bottles hanging on the wall are nothing when com- pared with the hundreds of pitchers hanging on these walls A One Mule Power Automobile OHN A. F. DE LION left Philadelphia for San Fran- cisco in a pushmobile with a mule hitched behind to do the pushing. And, stranger than this strange fact, His mule pushed him all the way. This proves conclusively that Mr. de Lion was not a freak or fool, but a very wise man who knew his own mule. This one lacked the dominant characteristic of his kind, balkiness, and therefore made excellent motor power. Since the mule took the place of an automobile engine, he was awarded a New York auto license. of engines being balky, but should they be mndelicately he got there. classed with mules? HEN you order steak you usually find a spray of parsley trimming the corner ot your platter. It is fresh and green—looks as if it had been picked in the garden of the restaurant just for you. Most likely it grew ona farm many miles away and had left home long since. How does it stay so fresh? It is very carefully packed in sugar barrels when it is shipped. A large piece of ice is tucked in each We have heard The automobile and the engine. Popular Science Mo Pitchers, Pitchers Everywhere HIS is Mrs. James Hensley of Knoxville, Tenn., and she OWns two thousand pitchers! She loveg them and collects them. One of them, low, squatty, and black, was made by the Aztecs in Mexico back in the fourteen hun- dreds. .Another is a clown and near it is a little red devil whose taj] serves as a handle. A _ copper pitcher from Algiers looks in heathen wonder at a sombre gray pitcher made by Anton Lang, the Christ of Oberammergau. In one room corn pitchers are predominant. But there are also watermelon and pumpkin pitchers, Another room has been turned into - a pasture where cow pitchers graze on the floor. We know gasoline is dear but really there is a limit! How This Little Soup-Green Went to Market barrel and then the barrel is covered with burlap. In this cool, dark, damp condition the parsley does not dry up. The sun that makes things grow will ruin them after they are picked, so they must be well protected. Take the case of the cantaloupe. It is picked when mellow and then rushed to the shade of a cantaloupe house for packing. The house is but a rudely built, brush-roofed shed, which is torn down when the packing season is over. - But the melons would have reached market over-ripe had the packers ‘‘let a little sunshine in.” In fact most tropical fruits which are shipped to us are sent unripe. They) finish the ripening process on the way | —that is why they don’t taste so’ sweet when we get them as they do when picked right off the tree and eaten right away, for they need sun. — Cantaloupes must be packed in the shade to keep them from getting over-ripe, so temporary sheds are built 60 Parsley is carefully packed in sugar barrels. barrel contains a cake of ice and is covered with burlap Each

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- are into - TAZe July, 1919 Making the Tides Work for Us When the world’s coal supply is finally exhausted we may turn to the tide motors which commerce now scorns ARNESSING the heat of the sun and the power of the tides and making them do useful mechanical work for mankind have always been two great dreams of inventors. Perley Hale, of San Diego, California, has invented the method for taming the tides shown in the accompanying illustration. Trapping the Tide Two series of reservoirs are located one above the other between high- and low-water marks. Each of these is open on the sea side by means of automatic gates working by gravity, so that on the rising tide water is trapped in the upper reservoir. If this reser- voir is of sufficient volume, enough water can be stored in it to operate a water turbine in the bottom. The water passes through the turbine and down into the lower or waste reservoir, where it is retained until the tide has By Joseph Brinker fallen sufficiently to allow it to drain off into the surface of the ocean. The working of such a tide-water plant may be compared to that of a reciprocating engine having a gigantic piston which moves up and down twice a day (once for each tide). Mr. Hale’s plant is very different in nature from the motors which are driven by the intermittent action of the waves and are much more complicated machines. The rapidly rotating turbine, mounted on a vertical shaft, could be made to drive a generator to provide current which could be used in manu- factories built on top of the reservoirs or transmitted inland by wires for other power purposes. While a tide-water plant like that shown might be located at any point along a coast, more power could be secured if it were situated where the rise of tide is abnormal—as in the Bay of Fundy, where the rise and fall is seventy feet. The head of water in the top reservoir above the turbine would then be greatest and similarly the power developed from that head. While both the harnessing of the heat of the:sun and the power of the tide are feasible, engineers condemn both enterprises as commercially im- practicable. It is the tremendous cost of the construction of the reser- voirs and the small power output due to the low head of water, except in extreme cases, which make the cost of tide power so great. Tide Power is Far Off Some day, when all the available river dam sites are utilized, when the supply of coal is as short as that of gasoline today, and when the heavy fuel oils have been exhausted or reserved for the navies of the world, if there are any at that time, then perhaps the tide motor will succeed. The water which flows into the upper reservoir during high tide is allowed, when the tide recedes, to flow through a turbine wheel. into the lower basin and thence into the sea. 61 The power may be used for any desired purpose

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Are the Panama Locks Too Narrow? T looks very much as if the two Eng- lish officers shown in the picture to the right were going to dance a “High- land fling” on the “blister” of their ship. What is the blister? Light steel air- tight pontoons which are built along the under-water sides of a ship to protect her from submarines. They project eight feet from the side of the ship. It is now known that Great Britain blistered many of her cruisers and monitors during the war, among them the Erebus and the Terror. These two ships were out alone ‘vhen they were attacked by severalsubmarines. Their blistering saved them and they were able to limp home. In a number of other cases the pon- toons proved equally successful, and the loss of speed through their use was very small—about half a knot. Because of these results-it is prob- able that in the future blistering will be applied to all battleships. That causes the Navy Department of the United States to ponder. The locks of the Panama Canal are 110 feet wide; the beam of our latest dreadnought, 97 feet wide; and the plans for future dreadnoughts call for a beam of more than 100 feet. Add 16 feet of pontoon—eight on a side— to these ships and they will be wider than the locks! If our ships are “‘blistered’”’ how shall we travel from coast to coast? Shall we change the width of the locks, of the ships, or of the pontoons? Or will it come to sending our largest ships around Cape Horn, as of old? Publishers Photo Service - Popular Science Monthly So International Film Service Air-tight steel pon- toons along the sides of a ship pro- tect her from sub- marine attack If we add sixteen feet to our dread- noughts they’ll be wider than the Panama Canal locks In the Belly of a Dirigible HE end of atunnel? No; the end of a dirigible as seen from the inside. The shining spot in the distance is the mouth through which the dirigible’ breathes. The huge bag is filled with hydrogen gas. As it rises in the air the pressure decreases and the gas tries to expand. But this would stretch the casing. So the mouth—a valve invented by a man named Gammeter—opens automatical- ly and exhales until the pressure within is normal, where- upon it shuts again. When the dirigible comes down the reverse is true. The pressure increases without and the bag tends to cave in. Balloonets—small balloons inside the dirigible—are used to keep the pressure constant on the way down. As the hydrogen contracts the balloonets are expanded. Working on the inside of a dirigible. ©B. F. Goodrich Rubber Co. 62

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where- true. O cave e—are n. As July, 1919 Flying without Wings Has Its Thrills Riding a bucking orientator provides most of the sensations known to the aviator T was the first time that he had peen alone at the controls of the airplane. John Harvey had the the- ory of the thing down pat, but how would theory and practice hitch up ?— that was what he was asking himself as the instructor saw that the safety pelt was properly secured and gave the order to go. A mo- ment later John Harvey was concentrating so fiercely on the pusiness in hand that all else forgotten. needy, old man,” he said to himself as he found that he was gripping the control- stick so tightly that his fingers ached, and he pushed the stick gently forward. The machine dipped its nose gracefully. Harvey promptly reversed the motion of the con- trol until he was again on an even keel, and pushing with his right foot on the rudder bar he swung around to the right. Suddenly he remem- bered that he wasn’t banking. He pushed the “‘joy-stick’”’ over and the machine tipped sharp- ly to one side—too sharply, and Harvey wrenched at the stick to avoid whirling completely over. Then things began to hap- pen. Jolted forward by the quick motion, Harvey uncon- sciously pushed against the control. Instantly, it seemed to him, the machine went into a nose dive. He tried to re- verse, but too late. The ma- chine was making an impossible reverse loop and Harvey’s senses were whirling with it. But he didn’t crash. Something held him suspended. “Tf I can’t get out of this one way, I can another,” he’ muttered, and pushed the stick far to the left. At once the car whirled over and Harvey’s ear canals—those keen centers of equilibrium within the inner ear— told him that he was right side up once more. Rough Going Harvey was digesting his new sensa- tions when the machine began to rock and pitch violently. Tug as he would at the controls, Harvey could not keep on an even keel. An imp of perversity was in the thing. If he pushed the stick forward the machine seemed determined to go somersault- ing eternally through space, and when he tried to bank, the blamed thing seemed to interpret it as an order to By Loren Palmer roll completely over. But little by little Harvey got the knack of the controls and presently he was master of the situation. Dangerous, not to say impossible stunts for a beginner? Not at all. John Harvey was as safe as you are Photograph by Division of Aeronautics, U. S. Army Whirled about in this machine the student-aviator develops the ‘‘ear-motion sense” so vital to the flyer sitting in your -chair reading this. He had performed most of the evolu- tions possible in a modern airplane— and some impossible ones—without ever losing touch with the solid earth. The explanation is the Ruggles orientator, a machine resembling some- what a giant gyroscopic top, equipped with a section of airplane fuselage, or body, and controlled in its movements exactly as is an airplane. It is used to train the student-flyer in orienta- tion and motion-sensing, and to ac- custom him to all the sensations of aerial spins. Such training means the difference between life and death. Maj.-Gen. George W. Squier said recently that 90 per cent of the flying casualties during the war were caused not by bullets, or badly built machines, but by “‘the failure of the man.”? In 1912 Wil- liam G. Ruggles invented a machine that would whirl the novice and ena- 63 ble the flight surgeons to test his reac- tions. But the need was for a way to teach aerial stunts and airplane con- trol without danger; so Mr. Ruggles improved his invention. He provided two sets of large steel rings, large enough to carry part of an airplane body, swung one within vertical and one within horizontal bear- ings and driven by small motors so that the rings revolve one within the other. The longi- tudinal axis of an airplane body, suspended by bearings on the inner ring, is also revolved by the motors. Adding controls, like those of an airplane, to enable the student to regulate the motion in any of three directions, both forward and reverse, the inventor had a machine in which the beginner could practice all the motions of flying and try all the tricks except leaving the ground and landing. Mr. Ruggles also pro- vided a dual control on the floor by means of which an instructor can control the movements o the car. Fighting for Control It was the manipulation of the floor control by his instruc- tor that caused John Harvey to think that the thing was be- witched when taking his first lesson. If the instructor’s ac- tion is not met and promptly countered by the pupil the instructor can send him spin- ning over and over, or around and around in a circle in either direction, or rolling sideways. But the mastery is always in the hands of the man in the car, provided he is skillful enough. When the instructor pushes his control-stick forward the car in the orientator begins to fall, or, more ac- curately, to turn with its nose down just as an airplane would start in a nose dive. The motion can be over- come by the student bringing his control-stick slightly toward him. - If the student fails to meet the instruc- tor’s move the car will spin on its lateral axis, performing a reverse loop impossible in an airplane. The other movements are started and controlled by the instructor or pupil moving the control-stick or the rudder bar exactly as in a flying airplane. Practice on the orientator develops ‘‘ear-motion sense,”’ which will serve a pilot when muscle sense and eyesight fail to do so.

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With many advantages over the cold chisel, this tool makes a clean round hole in metal, slate, asbestos, lin- oleum, automobile bodies, boilers, tanks, etc. It can be operated from any position This belt-fastener with teeth like those of an alligator has great tensile strength; it grips the long fibers of fabric belting and is smooth on both sides At the right is a port- able bench-plane run by a_ small _ electric motor. An automatic safety guard prevents the operator’s injury Do That Hard Work with Tools and Machinery Weighing the iron as it runs into the ladle, the operator reverses his controller- and brings the mixer back into position, auto- matically shutting off the flow of metal ‘ Popular Science Monthly The eight holes in the hub are drilled by a jig which fits over its out- side diameter. The air- plane propeller is made from spruce of the best grades, and it is drilled in the short space of three minutes When the guide hooks are set over the wire joint the wireman presses a bulb and the connection is soldered neatly. No solder is wasted Cleaned but once in twenty-four hours, ‘it not only saves com- pressed air and heats more rivets, but heats them with uniformity eee F ee eee When the pipe is welded the coil- This machine makes the cutting A. handful ‘ of -letters set under ing-machine forms its length into and handling of odd_ shapes, the machine is tied in the space a coil. Then back it goes for inside cuts, and plain cutting a of five seconds, thereby elimi- another section to be welded on quick and inexpensive operation nating hand tying and extra help 64 eet a. ee ge a

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uuu oO July, 1919 Housekeeping Made Easy Some devices that will save energy in the home Particularly adapted for desk use or the bridge table is an elec- tric fan which carries its own battery. The blade arrangement pre- vents the blowing away of whatever is be- neath its wind current No more _ aching arms are necessary to get your packages home. A_ curved piece of metal fits over two fingers, and strings from as many as twelve packages may be slipped into it Just high enough to enable mother to give baby her bath. Tub and stand are of white enameled wood. At one end is a convenient towel- rack. Dressing is made easy by plac- ing a sewing-table across the top re ee 4 wad Bundle your soiled : os clothing into a par- Keep your shaving water hot over- Tae packear ay: night in the fireless cooker while and, lo and behold, ee camping or on an automobile tour. ~ your laundry wor- oom Try it and get a smooth shave ries are over WATER IN OWER An attractive, simple way of making A set of containers to hold cookies, When baby’s ted is not in use, it coffee on the dining-room table is ac- etc., in a store. Push a lever and is quickly folded and slipped complished with this glass percola- the glass jar tilts, at the same between the spring and the frame _ tor; the coffee does not touch metal time lifting its cover automatically '. Of the bed to which it is attached 65

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Making a New Fuel to Order How colloidal fuel helps oil and coal to do more work By Walter Bannard HE mightiest war-ships burn under their boilers not coal but oil. In 1917 and 1918 it was so diffi- cult to obtain oil that for a time it seemed as if the battleship fleets of _ England, France, and Italy would be unable to perform their task of bottling up Germany and Austria. The situa- tion was alarming. The submarine was literally turning off the spigot of Europe’s oil supply. In this emergency the engineering committee of the Submarine Defense Association of New York, of which committee Mr. Lindon W. Bates is chairman, determined to-begin a series of investigations to meet: naval de- mands. An oil expert of inter- of violent agitation, dancing about irregularly because of the collisions that incessantly take place. Preventing the Powder from Settling Colloidal fuel is simply a mixture of very finely powdered coal, oil, and a stabilizer (“‘fixateur,’? Mr. Bates calls it) to prevent the coal particles from settling in the oil. The nature of the fixateur is not Popular Science Monthly from thirty to forty per cent of coal in oil. In a colloidal fuel about forty. five per cent oil, twenty per cent tar, and thirty-five per cent pulverized coal can be combined, thus displacing more than half of the oil and securing equal or greater heat values for each barrel, thereby saving much money, At least twenty-five per cent of the fuel oil now burned is conserved and the world’s supply of liquid fuel ig increased by fifty per cent. Oil refiners have always won- national renown, he decided that a composite of oil and finely powdered coal would meet the demand. It was not a new idea; but it had come to naught because the heavy coal particles always settled in the oil. Some way had to be found of holding the minute coal particles in suspen- sion for anumber of months. When the problem was solved “colloidal fuel’? was created. Particles that Always Dance What is a colloid? Chemical history answers. Between 1861 and 1864 Thomas Graham dis- ~ covered that, when certain dis- solved substances are separated from a surrounding solvent by a membrane of parchment or fish-bladder, some of them pass through the membrane freely into the surrounding solvent, while others re- main behind, only to diffuse very slowly. The particles that do not pass through are evidently larger than the pores of the membrane. Graham called them ‘‘colloids.”’ Victor Henri, a French scientist who has done much to explain colloids, says: ‘“‘There are no colloids; there is only a colloidal state, just as there is a solid state and a liquid state.” When you blow a puff of cigarette smoke from your mouth you see a gaseous colloid of carbon. The finest ruby-glass is a solid colloid of gold. In a colloid there is no chemical union or combination between the particles held and the medium that holds them. A current of electricity passed through a colloid drags the particles with it. _ These particles are always in a state The “‘fixateur” is the magic substance that prevents the finely powdered coal from settling in the oil. You can compound colloidal fuel to suit your requirements. This picture shows a drug-store way; manufacturers will use machinery disclosed. It produces a state in which the force of gravity is so far overcome that the mix- ture of coal and oil remain permanent for months. When settling does eventually manifest it- self, brief stir- ring is all that is required to restore the fuel to its previous con- dered how they could dispose of their residues profitably. Col- loidal fuel supplies the answer, The ‘‘Cinderella products of re- fining,’ as Mr. Bates calls them, can be used to prepare a fuel that will command a premium because it is valuable in making the higher grade alloy steels. It Can Be Pumped Like Oil « Colloidal fuel can be com- pounded like a prescription. This means that the particular kind of fuel best suited for a particular plant can be made by a central laboratory. One com- posite in the range of ordinary temperatures is composed of sistency. It is possi- ble to sustain for months the oil refiner. “anthracite rice.’’ 66 In the first can is the “‘fixateur.” wax tailings—a residual waste which has always bothered The second contains In the third can is a binder; in the fourth The bottles contain liquid colloidal fuel and pressure still oil used in colloidal mixture

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f coal forty- at tar, erized lacing curing r each 10ney, of the d and fuel ig 3 Won- ose of Col- nswer, ; of re- them, a fuel 2mium naking els. e Oil - - com- iption. ticular fora ade by e com- dinary sed of July, 1919 half coal and half oil. Another ws semi-liquid is nearly three fourths coal and one fourth oil. The more coal that is added the more paste-like the fuel becomes. But all the pastes are mobile up to sixty per cent coal, and are pumped and atom- ized as if they were liquid. _ With the liquid grades the oil-burning equip- ment of a vessel or a plant need not be changed. At sea astonishing results sidering the conservation of oil and the reduction of transport. : Oil is now extensively used in furnaces of various kinds—brick-kilns, annealing plants, blacksmith shops, brass foundries, and steel works. About seventy per cent of the oil burned by these furnaces can be made to do the present duty of one hun- dred per cent, and more cheaply at that. have been secured. The net saving of oil on the research vessel with which the Submarine Defense Association experimented amounted to twenty-seven per cent. Moreover, with the same tank or bunker space a longer cruising radius without refueling is obtained. A war-ship or a merchant-ship can increase its steaming radius up to twenty-five per cent. Cost Savings The savings of cost in- volved in the use of col- loidal fuel are remarkable. An industrial company in BA ft VE Spas PMD te pen 28D HOR ROMEO, barrels of oil with coal incorporated and used as colloidal fuel will be ample for the full output, thus effect- ing a saving of about five hundred thousand barrels a year. In industrial plants many millions of barrels of oil zre consumed annu- ally. If only twenty-five per cent of this oil were displaced by fluidized coal great savings would result. Three anne Ohio burns three hundred bushels of oil per day; its oil costs seven cents a gallon; its coal five dollars a ton. A saving of fifty-five cents a barrel, or one hundred and sixty-five dol- lars a day, is effected by the use of colloidal fuel, quite apart from con- A -certain steel plant. uses three thousand barrels of oil daily, and soon it will require four thousand five hun- dred barrels. But the three thousand Coal that is useless for ordinary industrial purposes is pow- dered and mixed with oil to make colloidal fuel. is made to go farther and our fuel resources are conserved Thus oil million barrels of oil em- ployed in colloidal fuel could do the work of over four million straight barrels. The oil reservoirs of the world are being drained to their very dregs. We must conserve oil, but not at the expense of industry. Using Low-Grade Coal Colloidal fuel opens the doors wide to let the world have from the stills all the assistance it needs without starving hungry boilers or flaming furnaces of the grosser fluid fuels which constitute their food. Moreover, great deposits of low-grade coal, as well as large quantities of lignites, brown coals, and waste dusts, are added to the world’s fuel supplies. The world is familiar with three kinds of fuel—solid (coal), liquid (oil), and gas. We now have a fourth fuel which promises to become of world-wide importance. ' Farming without the Aid of Laborers OW large a farm can one able-bodied man, unassisted, plow, cultivate, plant, and harvest with a fair degree of efficiency? Not so very long ago it would have been considered extremely presumptuous for any unaided man to under- take the cultivation of a farm of more than a few acres. Now, however, thanks to the formidable array of labor- saving machines invented and placed on the market in recent years, itis by no means beyond the range of possibility for an enterpris- ing worker to cultivate by it. from twenty to a hundred acres, according to the kinds of crops-he expects to raise. The power-driven culti- vator shown in the accom- panying illustration is one of the recent additions to the labor-saving! agricul- tural machines that have completely revolutionized farming. The machine, which is shown in the picture in the capacity of a cultivator, may also be used for drill- ing, planting, and sowing— special attachments quickly 67 This machine, run by one man, will cultivate, plant, or sow a fair-sized field in a few hours, and, it is said, will do the work better than it could be done by a half dozen men using implements of a more primitive type adapting it for the particular work that is to be done This machine is equipped with six rollers for breaking up the clods after plowing. By adding one or more rollers the capacity of the machine may be materially increased. It. can also be used for planting three or more rows at a time. With a different attachment the machine can be used for sowing oats or grass, and by still another attachment it may be adapted for drilling the ground or row-planting. The drive wheels of this versatile agricultural ma- chine are also its steering wheels. The power is sup- plied by a gasoline engine, and one man can run it easily. The construction of the machine is simple and sub- stantial. To make the changes for adapting ittothe different kinds of work which it is capable of performing takes but little time and does not require the services of an expert machinist. With a machine of this kind in his possession, the farmer is truly independent of the labor market.

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nares SSS 1 A New Universal Multi-Service Motor-Truck Popular Science Monthly | Body meen 88 8 fe ee : oe & Fe Ee 5 2 a ae © Different forms of sides go to build up these universal bodies for trucks; they are designed for various uses N Indianapolis motor-truck body-maker has brought out a universal type of body to fit trucks of from one to two and one half tons capacity, provided For carrying large loads of boxes, barrels, and the like, this body is excellent; it is easily taken down stake sides, depending upon the kind of goods the truck purchaser desires to carry. Each side unit ig provided with lugs along the bot- tom edges which fit into slots cut the frame length back of the driver’s seat does not exceed 130 inches. He has gone a step further and provided a means to supply several types. The body is made applicable to all chassis up to two and one half tons capacity by means of adjustable longitudinal sills. Each body has the same platform, with different forms of sides to give it a small or large volumetric-capacity. It is this com- mon floor and adjustability of mount- The usual type of truck body can be set in place in a very few minutes ing which differentiates this new design of body from the eight-in-one convert- ible type with fold-up slat sides previ- ously described in POPULAR SCIENCE MONTHLY. The body may be used as a plain platform with no sides whatever, or it may be furnished with low solid sides, low slat sides, or high slat or at corresponding distances in the base platform. Several of the different types, all mounted on the same platform, are shown in the accompanying views. Cabs for the driver are also furnished for the various types. In each cage, however, the cab is a separate unit, Both cabs and bodies are shipped knocked down, so that they may be shipped for much less freight charges than the set-up type of body. PINION As Sure-Footed as a Mountain Goat = LV S you look at the pho- tograph below you will say to yourself, ““Im- possible.”” But what you see isn’t a test at all— it’s only a part of the day’s work; for this kind of a differential, attached to your truck or car, turns it into a veritable tractor. This is, figuratively, what the differential ac- complishes by a uniform pull on both driving wheels, operating on a new and simple principle. It does everything that the complicated differential of. the conventional type does, so the makers claim, and in addition pro- vides a retardation or locking ac- tion which prevents spinning and skidding. Only four plates compose this differential—a driving plate, two grooved blocks, and eight steel balls through which the power is trans- mitted. When the car or truck is running in a straightaway, all these parts revolve as a unit. When the wheels are revolving at different speeds, the position of the cam- blocks changes by reverse move- ments in relation to the driving plate and balls. Those of you (and who hasn’t?) F ™ _ ws = who have been stuck in a mud-hole : pee . eine i Se.” ete, will immediately realize the value %;, ” of such an accessory, for it does away with that expensive span of mules that are so necessary to a stalled motor vehicle. For the truckman or store delivery this type of body is a decided advan- tage, since it permits carrying any kind of load. Not many parts to get out of order, are there? And : it’s as simple as it looks The detailed plan above shows the simple construction of the differential Pulling out under its own power is a feat not often accom- plished by a truck of the size shown here

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unit ig he bot- ots cut in the types, rm, are WS. rnished h case, e unit. shipped may be charges under its is a feat accom- truck of wn here ‘July, 1919 Making Cylinder Reboring Easy HEN run for a long time Ford cylinders often get out of round, necessitating reboring—at best, a long and tedious job. A mistake means that an entire new engine block is necessary. Mechanics and Ford-owners will surely welcome a device that eliminates all chance from this operation and speeds up the work. ee These reamers are set exactly 3.781 in. in diameter, or the exact size to fit the oversize pis- tons furnished by the Ford Company. The blades are made of the best qual- ity steel, and can be adjusted to larger or small sizes at will. As they are made interchangeable, the blades, the shank, or any other part of the reamer can easily be replaced. By means of screws the blades are made adjustable to the cylinder to be bored Taking off just enough to make the cylinder wall true, the device eats its way downward Ignition troubles are reduced to a minimum by in- stalling this device upon your car’s instrument-board Spark-Plug Trouble? Locate It from the Seat “ AHA, there’s something the matter with your en- gine,” said the old-time motorist, anticipating great fun in watching the amateur locate the trouble on his new car. But the driver simply pushed a switch in an instrument attached to the dash, and instantly a series of sparks appeared at six little windows—No. 3 window being left black. Thereupon the amateur screwed in another spark-plug, and in two minutes the car was on its way again. This device is attached to the instrument-board of a four- or six-cylindered car, and is wired in series between the distributor or the magneto and spark-plugs. By pressing all the buttons except one, the current to each cylinder except the one being tested is cut off. If the plug is bad the engine stops immediately on that cylinder. A Farm Tractor Engine that Really Burns Kerosene HERE have been so many unfounded claims on the part of farm tractor manufacturers that their tractors would burn kerosene suc- cessfully that the wise farmer has arrived at the place where he has to be shown before any such claims can become anything more than claims. With kerosene at its present price as compared with gasoline, it is, of course, advantageous to use kerosene if it can be burned successfully, and provided its use does not seriously affect the engine’s lubrication by some of the kerosene HEATED KEROSENE TO CYUNDER The mixture from ° : m the carburetor passes Power as a cold mixture, since with the cold cult to vaporize than gasoline. Heat is the most active agent to help vaporize kerosene quickly, and heat is employed in the new device when the engine is to be started or run on a light load. While heat has its advantages in making . it possible to start a kerosene engine, it has ’ its disadvantages once the engine is running at its full speed and is put under its full load. Then a heated fuel mixture has not as much passing down the cylinder walls past the pistons to a chamber heat- mixture the expansion of the fuel takes place in into the oil reservoir or result in the speedy ¢4 by exhaust gases the explosion chamber of the engine. deposit of carbon in the engine cylinders as a result of incomplete combustion of some of the fuel particles. To overcome these diffi- culties, one of the oldest farm implement and trac- tor companies has devised what is called a kerosene shunt for the purpose of burning kerosene in the horizontal engine fitted in its line of farm tractors. In discussing kerosene carburation, it must be Temembered that, while kerosene has a greater num- ber of heat units or will deliver up more heat from a given volume than gaso- line, kerosene is more diffi- Successfully burning kerosene, this engine does not carbonize or clog its lubricating system 69 The shunt shown here- with is designed to meet both of these conditions. In starting the engine or while running on a light load, the fuel is heated by setting the throttle valve so that the mixture from the carbureter must pass down a small pipe leading to the top of a small cham- ber heated by the engine exhaust gases. The heated fuel passes out of the bot- tom of the chamber and then up a second small pipe that enters the pipe leading from the carburetor to the intake manifold be- tween the throttle valve and the cylinders.

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To write one character, the sailor in the picture simultaneously punches six typewriter keys They Write Braille NE hundred and twenty-three Americans, blinded in the war, are stationed at Evergreen Hospital, Baltimore. Are they wondering listlessly how they are going to live? No, they are work-’ | ing hard trying to teach their fingers to read for them. They go regularly to the Red Cross Insti- tute for the Blind and iearn to read and write in as Well as Read It bars as there are letters and figures to be printed—just as in the case of an or- dinary typewriter. You press a key and it moves the corresponding finger- bar. The finger-bar sets in motion the movable frames to which are at- tached the embossing punches. This new machine will lead to much more litera- ture for the blind. For Popular Science Mong How to Make Smal] _ Maps from Large Ones — A any time a sunken derelict may drift into the path of an unsuyg- pecting ship; for the restless seq moves hidden objects about itg depths, continually changing the direction of currents. Asa result the United States Coast and Geodetic Syr. vey is always out looking for trouble, When they find, for instance, that a sand-bar has disappeared from one place only to reappear in another, they note it on their maps and then make new charts. The maps are sometimes reduced by photography; but when the reduction is great, or when the original maps contain many unnecessary details, the work is done by hand. In that cage the pantograph is often used. In man- ipulating this instrument the draughts- man moves a pointer over the lines he wishes to reproduce. The pointer is at the end of an extended arm of a jointed parallelogram which is fast- ened at one corner to a metal stand, A vertical pencil is attached to the center of one side. As the pointer moves, the pencil traces an exact but smaller reproduction of its movement on a sheet of paper beneath it. Braille, the language of raised dots. Each Braille character is made up of six dots arranged in two vertical rows of three each. Some of the dots are light and others are heavy. The relative positions of the light and heavy dots determine the letter. When a blind man has learned to read them well, then he will be able to write on the usual Braille machine, which has six punches to corre- spond with the six dots. All six must be punched at once to make a single letter. But suppose the soldier has only one hand, or, even less, one or two fingers? He will not be able to work six punches at once. Norbert Lallié, a French scien- tist, has invented another writing- machine which has a regular alphabetical keyboard like that of a typewriter. It can be worked with one finger if necessary, and without any knowledge of the Braille characters. The soldier learns his alphabetical keyboard. When he wishes to write the letter ‘“‘a,” he simply punches a key marked ‘‘a.” Six rods under- neath promptly swing into posi- tion and register the six Braille dots of the letter ‘‘a’”’ for him. In the new Braille machine, which works like a typewriter, there are six embossing punches and six movable frames, each of which has a punch attached. There are as many movable finger- This Braille writing- machine has a regular typewriter keyboard. The operator need not read Braille For this work of reduction the Sur- vey also uses a “hair frame.” The draughtsman wraps his map around a - wooden roll, and places above it a sheet of celluloid marked off in large squares. He puts his chart on the table in front of him and on it places the “hair frame.” This is a metal frame on which there are cross hairs placed in exact propor- tion to the celluloid squares with reference to the scale of the two drawings. The draughtsman corrects his chart by hand, being guided by the cross lines. people who have their eyes will be able to write the Braille characters without even knowing how to read them. BE Le hee tutes Cross lines on the map and chart guide the draughtsman when he reduces maps by hand In reducing maps by the pantograph, the draughtsman moves a pointer over ‘the original map lines, and a pencil attached - vertically to the mechanism traces the lines in reduced facsimile on a sheet of paper 70

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laces 1etal 1airs por- iloid ence two ‘he ects eing nes, - oe ee mmm ea The Azores seem to have been providentially placed where they are in order to assist the transatlantic flyer. Travel to Europe by way of the Azores and it becomes possible to carry a large, paying load of passengers and mail To Europe in a Flying-Machine Lessons of the transatlantic experiment and the Popular Science Monthly’s ocean monoplane By Waldemar Kaempffert and Carl Dienstbach that the daring men who vaulted into the air from Newfoundland to cross the Atlantic are likened to Columbus. To be sure, they taught us nothing new about the geography of the world. On the other hand, the ocean air through which they traveled is as uncharted as was the ocean of water in Columbus’s time. Meteorolo- gically, it was a real voyage of dis- covery. The American Navy has reason to be proud of its transatlantic experi- ment. It was not imbued with the desire to win a rich sporting prize, but to prove or disprove a proposition scientifically. Hence the chain of destroyers that stretched across the path of flight. The essence of a scientific experiment is control. Every step must be watched. Nothing must be left to chance or acci- dent. [' is not merely by a poetic fiction Use Warships as Observatories For the first time, regular meteo- rological stations were established in mid-ocean, among them battle- ships with a radio range equal to that of most land stations. The practice should be continued. What better use can be made of destroyers, of battleships that must be kept in com- Mission regardless of expense, than to employ them as oceanic weather ob- servatories? Commercial companies, whose enterprise without scientific aid would be as adventurous as that of Hawker, will derive immense benefit from such meteorological work of the Navy; for they will be warned of im- pending danger. One great lesson was learned in the great American effort to cross the Atlantic. It is this: The art of flying is in advance of oceanic meteorology. If vessels of the NC type are to be employed for the crossing of the Atlantic—vessels lumbering and slow in comparison with the swift passenger- carrying transatlantic flyer of the fu- With this drift-indicator—very like a bomb sight—the true course of the seaplane can be established so long as the surface can be seen 71 ture—we must be able to predict the Atlantic weather twenty-four hours in advance. Tke Air—an Uncharted Ocean Where are the carefully tabulated observations that make that possible? Beyond a few joint experiments in kite-flying made from the decks of the Prince of Monaco’s yacht by Teis- serenc de Bort and Professor A. Law- rence Rotch, and by government scientists from the decks of the United States Coast and Geodetic steamer Seneca, nothing whatever has been done to explore the Atlantic atmosphere. Before regular transatlantic flying becomes a reality, the United States and Europe must systematically ex- plore the atmosphere over the ocean, just as the atmosphere over the land has been explored from the ground to a height of about twenty miles. So competent an authority as the late Professor A. Lawrence Rotch predicted, long before our vastly improved flying-machines appeared, that it would be feasible to cross the Atlantic every day of the year in northern latitudes if the permanent western planetary winds that prevail above ten thousand feet could be used. Unfortunately, support is poor at such a height; to carry much cargo there is out of the question. By skil- fully selecting his level, Rotch argued,

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the transatlantic aviator may avoid head-winds; a sufficient number of more or less favorable following winds are always available at medium alti- tude. This theory of Rotch’s, one of the pioneers, be it remembered, must be verified by systematic weather stud- ies and by numerous transatlantic voy- ages by both airplanes and dirigibles. If the successful trips of many machines vindicate Professor Rotch, commercial transatlantic flying is a matter of but a few years. In the present stage of aviation, it is almost criminal to use land machines over the ocean for passenger service. We have said that meteorology— transatlantic meteorology—has not kept pace with the demands of avia- tion. The obstacles offered by fog prove the assertion. The navigators of the NC flying- boats knew that fog is the aviator’s deadliest peril. It may be questioned, however, whether they were quite prepared for the peculiar variety of extensive, obstinate, high-sea fog, com- bined with a heavy sea, that proved the undoing of two of the planes on the way to the Azores. It is the old, old story, but is told with a new thrill. The pilot of the NC-4, suddenly deprived of all his subconscious visible indications of horizontal direction, became confused. The semi-circular canals of the middle ear (the spirit level in our heads) tells us whether or not we are on an even keel. Yet, for some curious psychological reason, he could not tell that his vessel was banked—in other. words, tilted sidewise so that it tended to run around in a circle. Wanted —a Substitute for the Human Ear In a fog a flyer’s sense of direction and sense of verticality are so far destroyed that he cannot tell at what angle the machine is banked. He guesses at the angle. The compass Lieutenant - Comman- der P. N. L. Bellinger, who captained the NC-1, which was com- pelled to alight in the ocean near Flores, two hundred miles short of its objective. The crew were saved, but the seaplane sank after being buffeted by the seas for many hours Lightest and smallest of those who manned the seaplanes, Lieu- tenant-Commander A. C. Read, of the NC-4, brought the “hoodoo is supposed to indicate direction; but when the needle wanders navi- gation is demoralized. Ifa machine executes one flying maneuver un- bidden and unperceived, it may execute any other equally unbidden, even a nose dive. It was the ap- pearance of the sun through the clouds that saved the NC-4 from running around in narrow circles. Clearly, it is unsafe to cross the ocean in an airplane without the aid of some positive indicator of hori- zontal direction, some instrument ¢ which, unlike the labyrinth of the ear, is not affected by centrifugal force if a mist obscures the sea. Such an instrument is Sperry’s gyroscopic level-indicator. A Great Wireless Station on the Azores The flight has also taught us the vital importance of maintaining radio communication under all con- ditions. The commander of the NC-3 had left his ground set ashore. He paid dearly for that. After he had alighted he became dumb, wirelessly speaking. He was able to send mes- sages only in the air with a trailing antenna. Although a half dozen destroyers were near enough to help him, his seaplane was as hard to see on the ocean as a speck of dust on a plate-glass window. Eyes and ears are appallingly limited in range. Only radio communication makes it pos- sible to protect a transatlantic boat flying in distress. To lay a true course for the small islands in the Azores in mid-ocean is at best a navigation problem of no mean order. But to lay that course through the air in a fog requires all the aid that can be given by modern radio apparatus. When we consider the mishaps that befell the NC-1, it is evident that without radio apparatus of fair range transatlantic journeys should not be his starting. ship” through to first honors after misfortunes had nearly prevented His was the only one to arrive at the Azores on the wing Popular Science Me A i> Each seaplane wag equipped with flares to light up the seq if a landing at night became necessary undertaken. So efficient must. the radio apparatus be that it can be used for reckoning latitude and longitude even though the machine may be compelled to float for hours, and even days, on the water. Since the Azores are likely to become of future aeronautical importance, they will surely become the site of a huge radio station, a veritable beacon of electromagnetic waves to guide transatlantic flyers as surely as a moth flies into a flame. At any moment, when that station is completed, the transatlantic aero-navigator may de termine his location and then head for the Azores. It may as well be admitted. that, however romantic it may be to cross the Atlantic without a stop, the direct route from Newfoundland to Ireland is of only academic interest for the. time being. Aerial commerce in flying-machines will surely move by way of the Azores, simply because it must be prepared to fight head-winds. Commander J. H. Towers, “admiral’’ of the seaplane squad- ron. His NC-3, lost in the fog, was forced to drop into the waves. After riding out a heavy gale she reached Ponta Delgada under her own power, but she was so damaged as to be out of the flight

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NLL SS SPW NN = = atess . seleSa™ saat SNH A A a og a The Guiding Fingers of Light that Pointed the Way at Night When Kipling wrote his ‘‘Night Mail,’ little did he realize that his idea of using searchlights to guide the nocturnal flyer would be practically applied in the transatlantic flight of the American seaplanes. Each one of the destroyers stationed in the path of flight to guide the argonauts of the air became a visible beacon at night. For miles and miles the long, rigid fingers of searchlights pointed high in the air to guide the men in the planes. 73 But the searchlights served not only as mile-posts to indicate the course. They were also used to indicate the true direction of the wind. Every scientific precaution was taken to help the men in the air. Since searchlights cannot penetrate a fog, the commanders of the destroyers received instructions to fire star-shells above the fog. Flares with a candle-power of several hundred power each were also to be used in emergencies

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Over the shorter non-stop route the machine best adapted to the task would only waste money. Why is this? Because the airplane has to carry fuel in place of money-earning cargo. What's Wrong with the Machines ? The American seaplanes were not prepared to fight head-winds. They were slow, heavy, cumbersome. ° Es- sentially winged sea-boats, they were not streamlined with that scientific care which is so much in evidence in fast fighting planes. In this respect the Sop- commercial flying. Its speed of sixty to seventy-five miles an hour is not what we expect. It is really a flying cruiser intended to detect submarines, and not a transatlantic flyer. Not one of the machines that earned transatlantic glory in 1919 was specifically designed for the pur- pose of flying over the ocean. Haw- ker’s Sopwith machine is a fast bomb- dropper. The Vimy - Vickers and Handley-Page biplanes are likewise bomb-droppers. Six hundred miles is the maximum range for which both the British machines and the American NC planes were designed. Much Popular Science Month effort so far as speed is concern If the business man who must be in London in forty-eight hours is to be deposited in England safely and surely, he must be transported in a machine that will plunge through adverge winds and storms as readily ag the Mauretania plows through heavy geag, What will be the aspect of the trang. atlantic flyer of the future? It must be an evolution of the fast fighting airplane if it is to depend on power and speed. Exactly what form it will take no man may safely predict. This much at least is certain: It will have a completely inclosed body or fuselage; ° it will have a speed of with machine of Haw- ker and the Martinsyde of Raynham were bet- ter. Although the Ameri- can experiment is scien- tifically more valuable than the British, there can be no doubt that - the transatlantic flyer of the future will more closely resemble the British than the Ameri- ican machines. Not that this transatlantic flyer will necessarily be a land machine, but that it will place its chief reliance on clean- ness of line, on engine power, and hence on speed. The NC planes are merely large copies of the old Curtiss flying-boat. © The engines are mounted outside of the hull—an objectionable procedure Lecause of the air resistance encoun- tered. Aeronautical engineers are well aware of this, but they have been forced to continue the practice because the propellers must clear the waves. But the larger the flying-boat, the less reason for continuing the practice. Any one can seé for himself how high the propellers of the NC boats were mounted above the water. The NC type has proved itself decidedly too slow for transatlantic Hawker When nearly in mid-ocean the single-engined biplane in which of the elaborate preparation for the flight can be explained by the provi- sion that had to be made for carrying extraordinary loads of fuel for a voyage far exceeding in length that for which any machine built today is really designed. The Popular Science Monthly's Transatlantic Monoplane Although the Americans collected more practical information on the sub- ject of transatlantic flying than did the British, it must be confessed that transatlantic flying in the future will more Hawker’s splendid duplicate and Lieutenant-Commander Grieve dared the Atlantic flight was brought down by a clogged water- cooling system. Their escape from death was miraculous one hundred and fifty miles, possibly of two hundred miles, an hour, The POPULAR Sclr- ENCE MONTHLY hag given this problem some thought. It pre- sents to its: readers the plan of Mr. Carl Dienstbach, its aero- nautical editor. You will find nothing revo-. lutionary in his plan; it is based on the experi- ence of the last ten years in flying over land and sea. Since the machine must cross the ocean, it must also carry much fuel; but the carrying of a heavy load and the attainment of high speed are almost incom- patible. An enormous lifting surface must be provided to raise the load, and much of this lifting surface is not only useless in the air, but decidedly detrimental because of the air re- sistance that it offers. Since there must be the utmost economy of surface and power, Mr. Dienstbach has decided that the machine ought to be a monoplane of about one hundred feet span. Curi- ously enough, the late Count von Zeppelin, after devoting the last months of his life to the construction of a mammoth seaplane, also arrived The NC-1 tuning up at the Rock- away Naval Air Station in preparation for the great flight. All of the NC boats are alike in general appearance

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‘te seas, rans- must iting ‘and take This have lage; ad of fifty two hour, Scr. has Ilem pre- 3 the Carl aero- You Tevo-. plan; x peri- bd ,; ten over chine an, it much Tying iment 1com- . irface load, is not dedly ir re- tmost , Mr. ; the ine of Curi- ; von last iction rrived » Rock- aration he NC earance ROOM Been REW IN BERTHS OFF DUTY at the conclusion that a monoplane is the correct type—a conclusion of which Mr. Dienstbach was not aware at the time he designed the POPULAR ScIENCE MONTHLY flyer. Mr. Dienstbach was inspired by the monoplane of Mr. Grover Cleveland Loening, probably the fastest that has thus far been designed and built. The Loening construction lends itself well for the purpose because it is so stanch, because it does away with fuel-wasting projections, and because it consumes little power for the speed attained. Now, in any - transatlantic flyer, speed is dependent primarily on per- fect streamlining, which means that every projecting surface must be so designed that the air is parted with the least possible resistance. It was the French designer Nieuport who was the first to attain racing speed in this scientific way. The narrow high fuselage of the Loening construction is a great ad- vantage because the engines can be placed within the streamlined hull. Because the machine has but a single surface it encounters less resistance in its onward progress than a biplane. At the start of a flight with full load it is practically impossible to vary speed; but toward the~end of the voyage the speed becomes more ad- justable as fuel is consumed. More- over, the flying angle can be reduced from that of the utmost efficiency for lifting to a flatter angle, which means still higher speed. The mechanical advantage of having the engine inside the hull is obvious enough. But will not the passengers be in- convenienced by the noise, odor, and vibration? Not if they are literally sealed in a mechanically ventilated saloon provided with padded walls. Of course, the quarters will be cramped, but not more so than in the NC flying-boats. They cannot walk upright; but they can lie com- fortably on couches. Moreover, “HYDROPLANE To gain speed the engines and passengers are enclosed in a perfectly streamlined hull. Note that the passengers must sit or recline. There is no room to walk about upright. Weight SOUNDPROOF SALOON: the passengers will be provided with every luxury. Their quarters will not only be ventilated, but supplied with warmed air. If the spectacle of an ocean dotted with ships interests them, they can enjoy it by looking out of their port-holes. There will even be elec- trically cooked hot food prepared by asmall cook, probably a Japanese, who must be a veritable genius. He will act as steward, purser, deckhand, and maid-of-all-work. It Will Have to Be a °* Flying-Boat The POPULAR SCIENCE MONTHLY flyer must be a flying-boat, for it is impossible to make a preliminary run at high speed on wheels in so large and heavy a machine. The machine that Mr. Dienstbach has in mind can vault into the air only if it can carry its load at maximum speed. Suppose the machine were mounted on ice-boat runners, and suppose that the ice area were infinite. In other words, a flying-machine thus mounted on runners would gather speed, travel faster and faster, until finally it would rise into the air. So long as the preliminary run is fast enough, the heavy load can be lifted. A way must be found to run or glide over liquid water as fast as it is possible to slip over ice. Much has been done in this direction by the hydroplane, but nothing comparable with ice-boating. e The fuel-tank of Raynham’s Martin- syde—it is large for obvious reasons " ADJUSTABLE ae HYDROPLANE ,X indicates a separate electric generator for the radio set—an all-important feature, as Commander Towers’ experience proved is precious, so that there cannot be more than three in the crew. Every passenger is weighed before he steps on board. He pays so much per. pound for having himself transported This solution is offered: Increase the-hydroplane speed by reducing the long, wetted, adhesive hydroplane surface, and give that surface such a shape that the maximum lift is at- tained with the least drag. This becomes possible if the machine is able to rise clear of the water on one step in front—a step of correct design. Now, this small hydroplane area will lift the whole load only at very high speed, and very high speed can- not be attained until the whole weight is lifted. We seem to be running around in circles. The only solution is to make this same small surface lift exceedingly even at slow speed, while the hull of the flying-boat is still in the water and offering therefore much resistance to onward progress. This end could be attained by what the airplane designer calls a variable camber surface. By camber is meant the curvature. It is hard to change this camber in the wing of an airplane; in fact, it has not been successfully done, because the complex construction necessary makes the wing either too heavy or too flimsy. But in a hydroplane varia- tion of camber becomes feasible. Re- member that in the water steel can be used, something solid and thick; the construction can be simplified. A hydroplane with a variable surface would act like a kind of crow-bar, a long lever to lift the craft. Hydroplane surfaces can be placed directly below the load and can be controlled from their centers. You have only to picture to yourself a well in the hull above this adjustable step or hydro- plane, much the same kind of a well that receives the center- board of a cat-boat. In this well is a row of hydraulic cylinders. The pistons emerging from the cylinders are fastened to a flex- ible steel plate lying normally flush against the bottom of the _ hull—a plate reinforced at the

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Popular Science Monthly’s Two-Hundred-Mile-an-Hour Transatlantic Monoplane If the Atlantic is to be crossed regularly by commercial flying-machines, they must -be vessels very different in type from the NC planes. Mr. Carl Dienstbach has designed the two-hundred-mile-an-hour Popular Sci- ence Monthly transatlantic monoplane. It is an elaboration of the Loening construction. fastening points by strong lateral steel ribs. Pump the cylinders full of water or empty them to a variable degree, and the steel plate can be made to bulge out or to flatten; any degree of con- cavity can be obtained. The location on the hull is such that if it be given no curvature—only a slight downward slant from front to rear—it constitutes the step so familiar to motor-boat speeders. With the help of subsidiary vertical surfaces adjoining it and moving in harmony with it (vertical surfaces that are slight prolongations of the hull’s sides), it performs the familiar function ofa step—a step that may be folded in the air against the hull so that it will offer no re- sistance. If the step be given a steep slant and a suitable curve, that ac- celerates the impinging water so sweet- ly downward that no eddies occur (exactly as a high lift wing acts in the air), and a trifle of a reverse “‘S’” curve at its tail end to dismiss the stream smoothly, it needs must give a strong upward pressure at lower speed as well, while the hull is still in the water. The hollow space behind the lowered plate and the vertical side plates communicates, of course, with the air through the well above. Getting Off the Water Let us watch the step in action. We start with a marked curve to the hydroplane to lift the hull out of the water at low speed. When the hull is well out we reduce the curve and increase the speed. Finally all the weight is carried at extreme speed on the small front step. A similar step behind the center of gravity serves as an elevator in the water. There is also a small vertical rudder which projects into the water and which is low enough to remain there after the tail has been raised by the 76 Popular Science Ma mS RSS =. i 4" adie = ae Bs elevator. Of course, the aerial con- trols help these water controls far more ° than in the ordinary flying-boat be- cause the water speed is so much higher. Once the propellers are run- ning, side balance is maintained en- tirely by the usual wing ailerons. These ailerons are very long, nearly as long as the wings, and across them blows the strong slip-stream of the propellers. Since air resistance is so important, we must look for the utmost cleanness of line in flight. We have not an ounce of fuel to waste. The hull of the . flying-boat must be given a better streamline than is to be found in the hulls of the famous NC planes. And, above all, it must be possible to fold away the side floats or pontoons that support the outer wings. Of course, this is no original idea. It has been found difficult to fold away the wheels of land machines, because they must be strong to stand severe shocks, and yet light. But floats, which are al-

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' July, 1919 al con- ar more * oat be- » much re run- ned en- . These as long n blows ypellers. yortant, eanness n ounce of the . better 1 in the ;. And, to fold ns that course, as been > wheels y must ks, and are al- ways necessary when a single center hull is employed, need not be called upon to withstand heavy shocks. Therefore, as our drawing shows, they can be swung back into recesses in the wings and covered with sliding screens when the machine is in motion. With the slip-stream side control just de- scribed, they are required only when the craft is at rest on the water. The very size of the monoplanesolves the propeller problem. The propellers can be mounted out on the wings, so that they can be driven through bevel gears by the athwart-ship engines. Nothing is detracted from efficiéncy, because the single reduction gear can be embodied in the bevel gear. So solid and thick is a monoplane wing of the Loening type that there | is ample strength and space for the propeller shaft mountings. In order to attain the speed desired—two hun- dred miles an hour—six Liberty en- gines and six propellers (four in front and two in the rear of the wings) are specified to attain the best compromise between efficiency and_ structural strength. The length of tubular shaft- ing required is only a slight dis- advantage; on dirigibles such shafting was employed long ago. It Can Live in Rough Seas The radiators have been borrowed from the Curtiss models, and likewise the long ailerons. Mr. Curtiss has given us a radiator of minimum re- sistance that has great cooling effi- ciency. Mr. Dienstbach has moved it from the sides of the fuselage to the top and shaped it like a long trunk. It will then act somewhat like a fin; but the chief advantage is that it is possible to utilize the exhaust as it is utilized on a locomotive—to send an extra strong draft through the radia- tor, cooling it in spite of the still further reduced head-resistance. 77 A craft of the compact type that the POPULAR SCIENCE MONTHLY has in mind can live in a really rough sea when unable to rise from it. Must it wallow helplessly? Not at all. .It proceeds on its own power, runs through a storm faster than it con- nects with a destroyer. The flyer will always start and alight in mod- erately sheltered water. When we fly to Europe we shall not need a string of destroyers across the ocean to help us in an emergency, nor need we wait patiently day after day until the weather conditions are favor- able. if transatlantic flying is to be commercial the crossing must be made according to atime schedule. Thetime- tables may be as elastic as that of a steamship:so far as arrival is concerned. If that ideal is to be realized, speed is necessary—extreme speed which makes it possible to cope with contrary winds without lengthening the trip immeas- urably beyond fuel endurance.

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Finding Your Way among the July Stars _Popular Science Monthly How observatories use the stars in correcting standard time By Ernest A. Hodgson, of the Dominion Astronomical Observatory that, although our sun appears to rise and set approximately 365 times a year, yet the earth rotates upon its axis 366 times, as shown by the meridian passages of a star. The interval between successive meridian passages of a star.is called a “sidereal day.” The interval between the successive meridian passages of the sun is called an “apparent solar day.” Now, the length of a sidereal day is always the same, but it fails to keep step with our apparent solar days. The latter are not uniform, so clocks cannot be made to follow them. Thus neither ‘“‘day”’ is prac- tical. We must there- fore adopt an artifi- cial time system. Since the true sun does not move east-’ ward among the stars at a uniform rate, we may sup- pose an average or mean sun to do so. It may be thought of as moving uniformly in the equator, rather than in the ecliptic, in such a way as to com- plete the circuit in a year. It will now transit our meridian at uniform inter- vals, and, as it is never far from the true sun, it will give us a day that keeps step with the ap- parent solar day. The interval be- tween successive meridian passages of the mean sun is known as a “‘mean solar day.” Twenty-four sidereal hours are equal to 23 hours, 56 minutes, 4.091 seconds of mean time. ** Standard Time” [ the article for June it was pointed out q NOZIUOH LSvV Artificial as this time is, it will not suffice in these days when two cities, separated by many miles in an east-and- west line, wish to do business with comfort. For the mean sun will transit the meridian of the easterly place (i.e., mean noon) before it does at the city to the west. This difficulty led to the dividing up of the coun- try into time belts, each approximately an hour wide, and assigning to each the mean time of the center of the belt. This is known as “Standard Time.” Now, on top of all the other artificial arrangements comes the daylight-saving scheme, thrusting Standard Time an hour forward in the spring and restoring it to normal again in the fall. The importance of accurate time cannot be overstated. An observatory can give time to within the hundredth part of a second. Removing from the operation (for the sake of simplicity) all the necessary refine- ments that are thrown about it, we may look upon the method as being somewhat as follows. A telescope is set up to rotate about a horizontal axis in such a way that it always points in the meridian. In an adjacent oziuoH HLyon ELOPARDAY *c AWE SOUTH HORIZON The Star Map for July The map above is specifically arranged for the latitude of New York, but is approxi- mately correct for any part of the United States, northern Mexico, or southern Canada. It shows the appearance of the sky at the following dates and times: June 7, Midnight. July 23, 9 P.M. June 15,11:30 P.M. July 30, 8:30 P.M. June 22, 11 P.M. Aug. 7, 8 P.M. June 30,10:30 P.M. Aug. 15, 7:30 P.M. july 8,10 P.M. Aug.22, 7 P.M. July 15, 9:30P.M. Aug. 30, 6:30 P.M. Sept. 6, 6 P. M. The magnitudes are indicated on the map by stars of various kinds as follow: 0, open cen- ter; 1, eight points; 2, six points; 3, five points; 4, four points; 5 is indicated by a single point. Eastern Standard Time. The Porutar Science Montaty is publish- ing every month an article like this by Mr. Hodgson. If you feel that these articles can be made more helpful, write to the editor. And if there are questions that you would like to ask about stars, send them along. 78 _ get our time from the stars. room a sheet of paper is drawn along by cloekwork under a fountain-pen. Ag long as the pen is still, a straight line is drawn. But every second the pen is twitched by a magnet operated by the sidereal clock of the observatory. How the Observation is Made To suppose a concrete case, let ys say that the observation is to be made on the stars at about 8 hours, 46 minutes, 30 seconds sidereal time. Some time before, the paper is started and the hour, minute, and second marked on the line drawn by the - pen. If the paper moves, say an inch a second, the interval between second- marks must be an inch. The magnet that twitches the pen is also connected elec- trically to a push- button beside the telescope. A. star has been selected which we know, from its position in the sky, to cross the meridian at 8 hours, 46 minutes, 80.26 seconds exactly. T he observer looks through the telescope, properly pointed toward the point where the star will cross. A hair line in the instrument marks the meridian. The star appears in the telescope and travels slowly across the hair line. As it does so the observer presses the button and an extra twitch is given to the pen. The sheet is removed. The position of the twitch is measured and found on measuring to have occurred at 29.76 seconds. -The clock, then, registered 29.76 seconds when it should have registered 30.26 seconds. It is therefore .50 seconds slow. WEST HORIZON Converting Sidereal to Mean Time The conversion of sidereal time to mean time is a matter of mathematics. The true sidereal time can be found by applying the determined correction to the sidereal clock. The mean time corresponding can therefore be computed and the mean time clock correction found. This time can be converted to standard time—again a matter of mathematics, and if necessary a further change made to give daylight- saving time. This, then, is the manner in which we Let us remember that, though the stars enable us to have a time system, the system itself is entirely the work of man and is almost as artificial a system of units as are the systems of length and mass.

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ong by \s long awn. d by a lock of let ug to be out 8 econds > time started 1inute, ed on oy the Paper inch a terval cond- be an t that pen is d elec- push- e the star lected , from e sky, ridian nutes, ‘actly, rough perly point is. £ marks oe and As it yn and The f the suring -The when s. 2€ mean e true ig the dereal © g can . time an be in a ary & light- 2h we ot us ble us self is ost as 2 the July, 1919 The Planets for July ITH the exception of the telescopic planet Uranus, W all the planets are grouped close together during July, and none are far from the sun, as the planet ws. oe a being west of the sun, is a morning star, + «ng just before the sun. errapiter is so near the sun that it will not be visible. It is in conjunction with the sun f } iia. on the 20th of the month. ~F pout on Saturn is fairly close to the ‘sun also, : / ~, put will be visible for a short time just after sunset. , Mercury is an evening star through- out the month, reaching its eastern elongation (i.e., the point where it is farthest east from the sun) on July 18. Venus continues to set as an evening star. It reaches its greatest eastern elongation on July 5. It will be a brilliant object in the western sky during the early evening, and will be the only planet that will make any notable showing during the month. The following are the only conjunc- . tions of planets with the moon worth | noting. Venus on the Ist and again on the 30th. Saturn on the ist and again on the 28th. Venus and Saturn are in con- junction with each other on the 1st, Venus being slightly to the south of Saturn. Note the extremely variable apparent rate of Mercury. It reaches its stationary point (i.e., it begins to retrograde or pass to the west among the stars) on the 31st. ’The moon avoids the sun at new moon, passing below it, and it avoids the earth’s ‘“‘shadow”’ at full moon, passing above it. There is, therefore, no eclipse this month of either the sun or moon. . ; SIN) gnaat * Snr4 a7 ™* Ys ~ ~ 4 ad To use this planet map, cut out the disk be- low and use it as explained: in “How to Use the Planet Map” How to Use the Planet Map Te planet map indicates a belt 30 degrees wide on each side of the celestial equator. To use it. proceed as follows. Take a sheet of thin card- board and on it trace the outside circle of the map, and also the sections of circles indicated by the broken lines. Cut out the disk and from it cut out the section bounded by the ry dotted circles. On it write in North, i! Zenith, East, West, A.M., P.M., Noon, yh Midnight, and the hours indicated by i | Roman numerals at the edge opposite / cu, the radiating lines. | | PT Ta | \ | | | | Now pin the disk, center to center, : d s over the map. To see the section of \ , | f | 4 \ .) iy | : w' | , | Hy » me / | " i} iy i > cor H ‘ U = \ south, and the stars will be readily \ picked up by glancing up from map to \ sky. The planets can then be determined. To find when any given star or planet will rise, transit, or set, turn the disk until the body is on the eastern horizon, in the center of the cut-out, or on the western horizon, as the case may be. Look opposite the date on the chart line of the mean sun and read off the time on the edge of the disk. Following are the signs of the planets: sky visible at any hour of any day in the month, turn the disk until the required hour is opposite the required date on the chart line of the mean sun. Now, keeping the disk fixed with | respect to the map, turn both until | the opening is at the bottom as you | hold the map before you. Turn to the To) MERCURY fe) SATURN b # }°>-°~4A | VENUS Q _ URANUS (0) ml i MARS ral NEPTUNE WY £4,%+=™}™“][—5 2a JUPITER. y SUN OAND MOON €

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Saree app TR a ae + Oe er a ae LE ee ae a ee pep ery A Capital for the League of Nations By F. W. Fitzpatrick

HEN there is a League of For nearly twenty years before a League of portions of the globe toward a

Popular Science Mo ; 7

Nations it must certainly Nations was generally discussed or even seri- central point of contact would have an office, a place in which to ously thought about, an International Society naturally further the expansion and transact its international business—. was hard at work preparing for it. This binding together of the world by a capital! This need for a world Society took official and tangible form some more fraternal ties. It would be capital has long been anticipated five years ago, when nearly all the learned, one of the most ancient cities of and prepared for. professional, and scientific international societies the world, one replete with historie Nearly twenty years ago a man _ banded together to establish a center for their associations and of infinite charm, already famed as a sculptor and meetings and headquarters. King Emmanuel of already the Mecca of all travelers, a economist, Hendrik Christian An- [Italy and President Poincare of France are city mellowed by age. dersen, conceived a ‘“‘World’s Seien- among its permanent officers. F. W. Fitz- Of course the actual selection of tific Center” with its university and _— patrick of Chicago is the Commissioner for the a site, the work of constructing the its post-graduate course in all United States. We hav: asked him to prepare city, must be carried on by the branches; a school for the pro- this article on the world capital—Epitor. officers of the League, to whom all fessors of the universities of all countries; wonderful libraries and museums; a world forum; a meeting place for international sports—really a world exchange or general clearing-house for all international activities. He also realized that sooner or later the nations would ‘tire of maintaining great arma- ments and navies, that there would be better and closer relations between them all rather than the groups of an Entente in one section and an Alliance in another; in fact, a League of Nations was the vision that presented itself to Andersen and his associates. Such a League must assuredly have a head- quarters, so, what more natural than that the world’s:scientific center should be combined with this headquarters and out of the whole a splendid world’s capital be evolved? For the past eleven years Mr. Andersen has given his entire time and effort to this wondrous project. His sacrifice and labor have been great. With Mr. Hébrard, of Paris, official architect for the French Government, and a splendid corps of specialists and artists, Mr. Andersen has planned an ideal city, monumental but eminently practi- cal in all its parts, and has had surveyed many desirable sites for such a world’s capital, at Ter- vuesen in Belgium, in Switzerland, at a point near Paris, and another on the Jersey coast. But the most favored today is just outside of Con- stantinople. It is a foregone conclusion that the Turk will no longer rule in that ancient city. By water and by railway it is easy of access to all of Europe. The establishing of the center there would facilitate intercourse with India, China, Japan, and Australia as well as with Africa and our Western lands. Making it such a world capital would go far toward establishing better practical and economic relations between the East and the West. Draw- ing the interests of these two great

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‘The World Capital has a scientific center, art center, libraries, museums, nations would delegate the necessary powers for expending funds and _ directing things generally. So far what has been done ig voluntary work on the part of Andersen and the Society he has founded. The King of Italy is its president and senators and distinguished men of other nations are on the board of directors, The society is called the World Conscience Society and its member-societies are the leading international associations of the world, eighty-six. of them: the Interparliamentary League is one of them; others, the International Peace League, the Esperanto Congress,.the Order of Good Tem- plars, the International Congress of Journalists, — and the International Federation of Labor. ~ This voluntary work has been but preparatory; it has paved the way for the League and offers it, when organized, its advice, the fruits of its years of toil and study, hoping only that the world may bea little better place to live in by reason of the Society’s efforts. Let. me quote a few paragraphs from Mr. Andersen’s splendid exposition of the Society’s hopes and purposes—from a paper read before the Union of International Associations at Brussels in April, 1912: ““A World Center must be composed of a series of centers adapted to all the aspects of man’s life. All the functions of international life must be there represented: a sporting center, destined in its utilitarian parts to the physical development of man and woman; an artistic center devoted to the cultivation of all the arts and to the conserva- tion of the monuments characterizing all the ages of humanity; a center for the international -institutions of science, and for those of letters; a © center for economic life, for judicial and political, for moral and religious life; andina manner synthesizing the functional ac- tivity of all the others, a center for the creative thought which moves man towards progress in all domains.”

meeting place for international sports, and headquarters for a League of Nations

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ard a would yn and ; Id by ld be ies of istori¢ ‘harm, lers, a ‘ion of | ng the y the om all essary recting lone ig nd the taly is d men ectors, science eading nty-six. is one eague, 1 Tem- 1alists, ~ This it has » when of toil y bea of the n Mr, ciety’s before ns at , series ’s life, ust be ned in pment ited to serva- le ages ational ers; a” | 1 and ndina al ac- or the ; man 99 ° . July, 1919 How to Test the Strength and Stability of Magnets ERMANENT magnets, usually in the form of horse- P shoes, are used for many purposes, especially in the construction of magnetos for certain types of automobiles. The useful- ness of such magnetos de- pends upon their strength and their magnetic stability. These qualities depend upon the nature of the steel of which the magnet is made, and upon the degree and efficiency of its magnetiza- tion. The initial strength pnd the stability of a magnet should be known before it is put to work. An instrument has been invented for determining and measuring the degree of magnetization and the stability of horseshoe magnets. A coil capable of rotary movement, to which is attached a pointer traversing a scale, is sup- ported between two iron pole pieces. This movable system and the scale are enclosed in an air-tight box. The pole pieces extend through the walls of the box into contact plates to which the two poles of the magne under test are applied. When a known current is al- lowed to pass through the coil, the pointer is deflected in proportion to A Voice from the Sky N aviator three thousand feet in the air said, ‘‘Buy a bond!”’ and crowds of people in front of the Treasury Department Building in Washington heard him plainly. Why? Because a “‘magnavox’’ was attached to the receiving end of the wireless apparatus. A magnavox—it means “great voice’’—is an amplifier which greatly increases the power of the ordinary speaking voice. This particu- lar amplifier was invented by Edwin Pridham and Peter L. Jensen. The great feature of the set is that the flyer’s transmitter is noise-proof. When the aviator said “Buy a bond” his Liberty motor was roaring only a few feet away; yet the people below heard only his voice. Because his transmitter was carefully enclosed? No; because his transmitter was care- fully exposed so that all external sounds would hit both sides of the diaphragm and neutralize each other. As a result the diaphragm would not vibrate. Then, when the aviator talked, that extra vibratory force exerted on his side of the diaphragm was the only vibration that registered. Because of this anti-noise quality, the magnavox is especially adapted for use in factories. Horseshoe magnets such as are used in magnetos are first tested for strength and stability by the instruments shown here. The usefulness of the magnet depends on the nature of the steel and the degree and efficiency of its magnetization ; the strength of the magnet, the degree of which is indicated on the scale. net is not affected by this test. The mag- For testing the stability of a magnet, two adjustable coils (solenoids) are . pro- vided which are located in front of the contact plates and fit around the legs of the test magnet. If a cur- rent is allowed to pass through the solenoids- in the proper direction, it will demagnetize the magnet un- til the pointer of the testing instrument points to zero. The value of the current required to bring about this result is measured by an ammeter and. indicates the degree of the stability ‘of the magnet tested. By this test the mag- net is deprived of:its mag- netic power. To make it useful it must be re-mag- netized. In practice the test for initial strength is ap- plied to every magnet in a lot, while only a few samples, picked out at ran- dom, are subjected to the stability test. The current for the movable test- ing coil is derived from a single dry cell, that for the solenoids from a storage battery. The solenoid current is regulated by rheostats. In the anti-noise ‘‘magnavox” the diaphragm of the transmitter is ex- posed; ordinary sound waves hit it on both sides and it does not vibrate; then the speaker’s voice alone will cause vibrations that can be heard These horns are all connected to one transmitter; when someone speaks into it, his voice will thunder up and down the street © Keystone View Company

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Sees a Me Popular Science Monthly Flying Above the Clouds to Catch the Eclipse | ‘Astronomer would mount his camera on a seaplane and soar to meet the sun TOTAL eclipse of the sun can never last more than eight min- utes. Usually it lasts much less. An astronomer will travel thousands and thousands of miles to an out-of-the- way place, in order to make the most of a few precious minutes. The actors in a play are no more carefully re- hearsed than are astronomers stationed at the various instruments. No one member of an eclipse expedition sees the eclipse as a whole; each one per- forms the special duties assigned to him. What if cloud or fog should steal between the earth and the sun?. What if it should rain? ll these elaborate preparations, all this tedious traveling, go for nothing. But fogs are always low- lying—never more than a thousand. feet thick. There- fore, if cloud or fog creep in between the earth and the sun, the solution is to climb above them and see the eclipse in all its uncanniness. No wonder, then, that astronomers are interested in the experiment undertaken by Professor David Todd, of the Amherst College Astronom- ical Observatory, of using a seaplane in which to rise high above the clouds to view the eclipse. Professor Todd's Experiment With the assistance of United States Naval officers and a seaplane, Professor Todd set out to take photographs of the sun’s eclipse which occurred on May 29. It was planned that the steamship on which the expedition sailed would stop at a point near the equator off the South American coast, launch the seaplane, and then stand ‘by while the astronomer tried out his plan. It might have been expected that Professor Todd would be the first to carry astronomy into the air. He is the most enthusiastic, indefatigable, and ingenious of eclipse observers. He even went so far, some years ago, as to devise a method of operating a whole battery of astronomical instruments from a central point, but was unable to employ his invention for the observation of the particular eclipse because the sky was at the time obscured. Although at the time of going to press the results of Professor Todd’s experiment have not been reported, it may be doubted if the plan of using a_ seaplane is practicable. Such is the vibration caused by a seaplane’s engine that the steady platform that must be provided for all telescopes becomes a shaking base hardly suit- able for Professor Todd’s purpose. To be sure, it was his intention to offset the vibra- tion by an elastic mounting of the telescope; but anyone who knows anything at all about the inertia of movable parts will admit that absolute steadiness can hardly be thus obtained. A More Practical Scheme? Professor George E. Hale, of Mount Wilson Observatory, has a far more practical scheme, to our mind. His plan is to send an unmanned balloon above the clouds, and to steady the cameras, which the balloon will carry, by means of a gyroscope. Professor Hale plans to study the corona—that ghostly appendage which surrounds the sun, and which is visible from the earth only during an eclipse—at any time. As we ascend in the atmosphere of the earth we finally reach a point, 82 What is the astronomer’s chief object of solicitude during a total solar eclipse? The corona. Only during the few minutes of a total eclipse is the corona ever seen by earthly eyes What can the astronomer do when, just as the moon is about to obscure the sun during a total eclipse, a cloud intervenes and obscures the view? Pack up his instrv- ments and go home. No wonder that Professor Todd decided to send a seaplane, armed with telescopic cam- eras, above the clouds, and thus make sure of getting picturestotake home withhim perhaps at an altitude of thirty miles or more, where the sky is not blue, but jet-black. The sky is blue because the air is filled with countless billions of dust particles that diffuse the light of the sun. In the inky canopy of the sky above the region of dust particles, where the air is extremely thin, the stars appear in their prceper places even in broad daylight. And the sun is a great blazing ball hung in the blackness. Its wonderful corona, the chief object of study during a total eclipse, gleams in all its pearly beauty. Should Professor Hale Succeed If Professor Hale succeeds in realiz- ing his plan, we need not wait for a total eclipse in order to study the corona but we can photograph it when- ever we please and study it day by day.

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onomer’s solicitude > eclipse? r during f a total ona ever y eyes nomer do moon is the sun e, a cloud cures the is instru- me. No sor Todd seaplane, pic cam- buds, and f getting e withhim ty miles ot blue, the air ; of dust t of the the sky particles, hin, the r places And the hung in | corona, luring a 's pearly ucceed in realiz- ait for a udy the ‘it when- y by day.

‘TREES may be used as receiving “and even sending antennae in radio-telegraphy and -telephony ac- cording to Major-General George O. Squier, Chief Signal Officer of the Army. With the ‘‘Floraphone,”’ as he calls it, not only have signals been received and sent by radio apparatus using live trees for antennae, but messages including multiple telegraphy signals have been received from local stations, airplanes in flight, other trees and the principal European stations. Explorers in unknown lands, farmers miles from communication centers, lost Army units, or airplanes forced to land, if in the neighborhood of a good-sized tree, can get into com- munication almost immediately, pro- vided they have a set of radio instruments and know the wireless code. International radio messages, news bulletins, the baseball scores, and such, can be received the moment they are wirelessed out, by simply cutting in from a tree station. It was in 1904 that General Squier first discovered the efficiency of using a direct metallic contact to trees, principally eucalyptus, while later oak, pine and poplar were used to increase the audibility of radio sig- nals. Thereupon he conducted some experiments with a view to utilizing growing trees as antennae for radiotelegraphy. During the course of sum- mer Army man- euvers in Cali- fornia, it was found that the regular Army ‘buzzer telephone land telegraph did not operate with an ordinary ground, due to the dry season and the soil, but

a wireless. (Above) Apparatus for working with tree ° “, &- ~ & 4 . ae re a6 ¢ ae J © 2 Le =

became opera- tive when connected with a nail driven in the trunk or roots of atree. <A report made by Dr. Squier wes forwarded to the War Department in 1904, but it was not until the recent war that any great practical develop- ment was carried out. In connection with the development of transatlantic radio work, under- taken to provide against a possible interruption of the submarine cable system, the Signal Corps established a chain of special receiving stations in the United States to record enemy and Allied radio messages for the informa2- tion of the Army. In this work the efficiency of growing trees as receiving

Tree Wireless Connect your wireless set to a tree and hear the world talk

antennae for this service, using the most modern apparatus, was thor- oughly tested and upon this work, conducted secretly, General Squier reported for the first time on April 25th, before the Physical Society of America’ assembled at the Bureau of Standards in Washington where dem- onstrations were made. Almost immediately the Signal Corps experimenters discovered that with the sensitive amplifiers now in use it was possible to receive signals from the big European stations, simply by laying a small piece of wire netting on the ground under a tree and con- necting an insulated wire to a nail driven into the tree within an outline of its top. Further experiments led to the discovery that one of the best receiving arrangements was an elevated tree earth terminal in the upper part of the tree top, and-an earth, or ground, consisting of several short pieces of insulated wire sealed at the outer ends, so as to radiate from a common center, and buried beneath the surface of the ground near the base of the tree. Such a tree antennae was also used as a multiple receiving set over widely different wave lengths, receiving either from sepa- rate terminals, at the same or different heights of the tree, or in series from the same terminal. The same apparatus was also used for transmitting and receiving tele- phone messages, although this was only tried out successfully over short distances. Wire and wireless methods were found to

coun is os, Hie. e * i. fn eqanT teeta be very readily linked up by this system. Radio telephone mes- sages from air- planes were re- ceived and transferred by wire to the city of Washington. Tree wireless pos- sesses great pos- sibilities, aecord- ing to General

A tree aerial 83 General Squier now “plugs in” on any tree and hears the news Squier and his aids.

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The House that Grew Popular Science Monthly " A young architect’s dream and how he made it come true Then a baby came and more rooms . were added. Two fireplaces kept the house warm during the winter RCHITECTS, as well as other people, dream about the kind of home they hope to have some day. But they have the advantage of being able to place their dreams on paper. The writer presents here his little home, in the hope that it will be helpful to young people in planning houses for themselves. It occurred to him that he could build his home on the instalment plan by erecting a small house, carefully planned for future artistic growth. He saw plenty of houses that had started as little shacks and been built up to large living-places, but the final results were hodge-podge affairs, made without definite plan. He therefore dreamed about the kind of house he would like to live in, and then cut it down, here and there, until he had a little house that could be built for about $1;900 in normal times. Then a complete plan was worked out by which this little house could, by additions through the years, be made to grow into the house he imagined. He found that it could be done in five distinct stages. At every stage of the game By Vandervoort Walsh Just large enough for a newly married couple is the little house in the beginning little, and then he could enlarge it as his savings permitted, and still avoid a mortgage. Now, the perspective views of the various steps of this house will prove that each one shows a house complete, and surely the picture of the final house gives no hint of the way it grew. The same is true of the plan. At each step, the house is complete in its equipment, and yet it grows logically. The pictures show this house to be built of white-painted clapboards; but this is not necessary. A stucco, or brick veneer, or shingle surfacecould be used. The shingles would cost about 5.3 per cent more per square foot than The family grew, as families will, which necessitated enlarging the house still further by adding the end wing the clapboards, the stucco about 32 per cent, and the brick veneer about 52.6 per cent more per square foot, But it must be appreciated that although this seems like a very great difference, it is not really so much when you consider that on the total cost of the house an increase of only about 7 per cent would be incurred by brick veneer, which is the most ex- pensive. In other words, the cost of the material on the exterior walls isa very small part of the cost of the house as a whole. In order to make additions as simple as possible, it will be noticed that the outside walls are divided into panels by wood pilasters. In this way, the house can be increased by units. The same precaution is taken with the roof. A horizontal board is carried around at the top of the first floor, and when the roof is lifted for the second story, this board acts as a belt course from which to begin the design of the second floor. If brick or stucco were used, these same panels of wood could not be dis- pensed with, for they are the secret of making new additions simple. In the beginning the house has only three rooms the house would look com- plete and artistic, and at no time would it look unfinished. The time be- tween the steps of growth could be as long as the builder’s pocket-book re- quired. Ifa period of hard time came, and he wanted to save, he would not haVe a big instalment bill to pay or a large mortgage interest to meet, for his house, would be as far as it went, hisown. In other words, when he built the first small step of his home, he would be able and a bath; but it is really a very comfortable and cozy little place, as the picture shows. The out- side dimensions of it are 23 ft. 6 in. by 29 ft., and the kitchen wing is 12 ft. 6 in. by 14 ft. It has a porch with an entrance in its narrow end, which, it will be noted, becomes ‘the main entrance of the next addition. There is also a back porch and ice- box entry, and a stairway to the cellar, where there isa laundry. The dining- to own it without mort- gage, because it cost very There was room a-plenty for all the grandchildren when the house was completed. A more artistically designed house no one could desire °4 room and living-room are | combined, which is not at all a disagreeable arrange-

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; will, > house d wing bout 32 er about are foot, ted that ary great sO much the total 2 of only -- incurred most ex- 2 cost of valls isa | of the 1s simple that the panels by he heuse ‘he same roof. A round at when the ory, this » ym. which nd floor. d, these it be dis- - secret of ing the “ee rooms t is really ible and », as the The out- of it are ) ft., and is 12 ft. 6 [It has a trance in which, it becomes ce of the There is 1 and ice- stairway ere there 1e dining- room are _ is not at arrange- . July, 1919 ment when economy is desired. A fine big bedroom, with a large bath and closet, adjoins. Of course, it must not be overlooked that there is also a small attic. It is a little doll house, perhaps, from the outside, but inside it is much more livable in than the usual four-room apartment. Everything Carefully Planned Now, it will be noticed that every- thing in the building of this house is arranged for expansion when the time comes. For instance, the chimney is puilt high enough so that when the day comes for building a second story it will not have to be altered. The porch is also built of as solid timbers as the rest of the house, in anticipation of the next step, when it will be converted into part of the living-room. The floor does not have the usual slope of a porch floor, but is prepared to be the under floor of the new room. The ceiling joists also are designed for the future. Instead of making them of light 2 x 6-in. timber, they are 2x10-in.; for some day they will be the joists of the second floor. Open spaces are boxed in the wall also, for the easy instalation of future plumbing and steam-pipes for the second floor. The door from the living-room to the porch is designed so that, when the = = *- 1 T ry PORCH quay TOUET BED ROOM cLo5- KITCHEN 0212-0 —- sme 5 a | DINING ROOM " & + 4 Living ROOM fonen 14-0 * 17-0 ‘FIRST STEP next addition is made, it can be re- moved and placed between the present porch columns under the entrance hood. The window on the porch will also be removed from the partition and used in the bedroom of the new exten- sion. The roof is so built that it can be easily raised when the time comes. This is done by having rafters rest on a double plate. The upper plate is bolted to the lower, and can be quickly released when the time comes. The rafters are spiked to the upper plate. When the roof is lifted, the jack-screws raise the upper plate, when the bolts that hold it to the lower plate are released, permitting an easy upward movement of the entire roof. The under plate remains in position, and serves as a foundation of the second- floor walls. The cornice line is built so that the raising will not destroy the appearance of the building. cellar is a sectional steam-heating boiler which permits of the addition of new sections as the building grows. Reaching Out and Up Now, let us suppose that after a number of years enough money has been saved to complete the next step. in developing the house. It will be seen in the plan that a living-room, a bedroom, and a new porch and chimney are added. The living-room extends out from the place where the old porch was located, so that a new porch is necessary, and this is provided at the corner of the dining-room. To supply a closet for the new bedroom, it will be noticed that the closet that served the old bedroom is divided in half, it having purposely been made deeper than necessary. A door is also cut into the partition to give access to the toilet. The main body of the house in this second step is 30 ft. KITCHEN 10-0 % 12-0 | s | '’ ' of Touer BED Room BED Room —~W-o x 14-0 106 *% 12-0 a. ci. n ." i DINING LIVING ROOM Room 1]-0 % 20-6 40x 17-0 l | ae wide. The front door opens into the living-room, and is now permanently located. The third step is not so costly as the second, and it probably could be made soon after the second. It gives an additional bedroom and porch. In this stage the house is a very complete ela as Os quia little bungalow, and is quite satisfactory for many years of waiting. The next step is | ia | | Eye ) it d DINING LIVING ROOM Room 1]-0 ¥ 20-6 M4p0x 17-0 PORCH Pe SM | | | a} r a costly one, since a second | Io] OF T enray an Torey me) floor must be added rot one toe xi2-0 and the roof raised. KITCHEN oo Fc q But, as the years ~ "a 4 BEO ROOM seated 7 ames 12-0 x 10-6 go by and the results of prosperity pile up, the thoughts of ex- } tending the -house ' sky-ward may be +H} _— 2 e103 PORCH very welcome. Now, E “THIRD STEP: As shown in the plans, the house was designed chiefly for comfort at all stages of construction a in order to do this, some means must be provided for getting upstairs. A stairway and a stair-ha!ll must 85 In the be built. Since the plan has had this in view from the beginning, it is not difficult to secure the space. What was formerly a bedroom can now be di- vided into a hallway and pantry, and the bath-room can be cut down to the size shown, to serve as a downstairs lavatory. In this fourth step only the roof over the central part of the house is raised. The pictures do not show this, but it is easy to see if the roofs of the wings shown in the picture of the fifth step are blotted out with the hand. It will be noticed that by lifting the roof of the central part of the house three new bedrooms are. added, two .toilets, and a sewing-room. On the exterior at the front, two large columns are erected to tie the design together and give dignity to the house. It is not necessary to build the railing around the top of the porches; this can be added when the final step is taken, BED Room 2-4 2130 SECOND PLOOR PLAN . PORCH _ rex Pawrnye moe KITCHEN 0412-0 Peet + ‘oom aac meet FIRST FLOOR PLAN Bev Room = SECOND FLOOR PLAN Sones tnTRy PANTRY XITCHEN pe . 10-0112-0 as DING ROOM “LIVING ROOM 40K tO No * 10-6 FIRST FLOOR PLAN To those contemplating house-building with a limited supply of capital, no better suggestions can be offered which consists of raising the roofs over the two wings. When this last step has been reached, and the wings on the second floor have added two new bedrooms and a back stairway; the house is complete.

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ee 1 i| i Sarees Rea carne ne oS EE IE SE aE ~ What -Can Be Done With An Old Car By E. L. Candler Winner of ‘the second prize in the Popular Science Monthly's contest E. L. CANDLER, of Grand Canyon, Arizona, won the second. prize of $100 in the POPULAR SCIENCE MONTHLY’S $300 contest for the best use of an old automobile, discarded on account of acci- dent or the antiquity of its mechanism. His idea is’shown in-the diagrams be- low, which indicate how he‘set up the engine of his wretked car in the cellar of his house, and‘ made its power drive a vacuum cleaner to help his wife with the housework, operate the. water pump, corn grinder, cream separator, dynamo to furnish current for electric lights, a butter churn and a saw table for cutting the winter’s supply of kindling wood. This method of utilizing an old car should be met with approval by other motorists, for there are many wrecks, with sound engines, which can be bought for a song from insurance companies. In relating how he came to devise the plan shown herewith, Mr. Candler writes: *“TUCK was against us. We had only owned our carfor a short time when we were in a wreck which com- pletely demolished the rear end of the car, but did not damage the engine. Af- ter thoroughly considering the matter we decided we could use the engine to good advantage and purchase an en- tirely new car. “Our home is a plain, old-fashioned house, of five rooms, kitchen, dining- and living-rooms. Above these are the bed-rooms, while below the dining- room and kitchen, forming an L, is a WATER ) TABLE CORN SHELLER. Ra, Sy NR N Op CORN CREAM GRINDER SEPARATOR WALL BRACKET CHURN Nt ‘aay : : i) a4}, ry 7" m Li i t shed, used principally for sawing and storing firewood. “We advertised and obtained a second-hand power vacuum cleaner at a low price and which, having been little used, was in excellent condition. The engine and cleaner were mounted and connected together by a clutch on a cement foundation in one corner of ~ the cellar, and a pipe run on the out- side of the house from the cleaner to the four main rooms and supplied I sey FOR CORN GRINDER ETC. K 4 - VACUUM CONNECTIONS The floor layout as viewed from overhead. Note the neatly de- signed layout of ma- chines, which will per- mit others to be set up at any time desired vACUUM ; CONNECTIONS . UPPER FLOOR. These diagrams suggest other in- dividual means CONNECTIONS of making use of LOWER. FLOOR an old automo- bile engine which otherwise would have tobe sold to the junkdealer. Naturally, the cooling system would have to be adjusted differ- ently; but this is a trivial matter when compared with the service it would give SHAFT CLUTCH FOR. ENGINE CLEANER yacuum CLEANER. CLEANER. EXHAUST 86 _ Popular Science Mo a with a hose connection in each room. The cleaner blows the dust into a large, closed barrel where a spray of water settles and carries it away through the drain from the sink, The engine also exhausts into this drain, which has the effect of deaden- ing the sound. “For sawing wood, running the cream separator, churn, bone and corn grinders, corn sheller, dynamo (used in lighting the house) and the water pump, a line shaft, carrying pulleys, runs underneath the floor of the kitchen and is belted to the several machines. “Other parts of the wrecked car were used as follows: The damaged tires were used for half soles and heels for work shoes, lining for wagon brakes, gate hinges and screen door bumpers and for trunk feet, which prevented the trunk scratching the floors, broom holders and strips nailed to the build- ing to support growing vines. “The inner tubes were useful for making fly swatters, sink stopper (disk form), gaskets for pipe unions, fruit jar rings, insoles for shoes, packing for pump and vacuum cleaner, weather strips for doors, a window cleaner and a pair of leggings for wet weather; also part of one of the tubes was made into a float for use in the swimming pool. ‘‘The framework we used for braces; the seats we mounted in a lattice sum- mer house; the top we made into a playhouse for the children, and the front wheels we used on a cart. “Considering the use we made of all the parts and materials of the car, the loss by the wreck was not so great. Almost any one can make good use.of their old cars in some of these ways.” It seems to us that some of the many automobile engines that can be bought second-hand could be made use of along these lines without wait- ing for a wreck.

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TUNNEL. TRAP POOR OPEN WHILE SHOOTING Gives / LIGHT ON TARGETS —+> i dina isiee ARGETS - SO FEET room. ito a ay of away > sink. n undaereground rire range » this aden- ° Ideal 50-foot range designed by W. J. R. C. boy zy the- 1 corn HERIDAN BARRIN- this manly and fascinating sport of town now that has not at least a small (used GER of Hillsboro, Illi- rifle shooting simply because he ao Sane, oct cco outa — : ; . : r eting amon water nois, designed the rifle doesn’t happen to have a rifle of his themselves for the famous Winehneter illeys, er —— - which own or live out in the country. Marksman, Sharpshooter and Expert Rifle- f the Sharpshooter earned for him the W.J.R. r man Medals. over Medal C. Special Service Pin. Start a W. J. R. C. “‘Unit’’ Get together with half a dozen of your : Barringer is 12 years old and a with your friends clar unit which will be oficially reaggulned Wy d car member of the Winchester Junior The Winchester Junior Rifle Corps National Headquarters. Any boy who starts ee — ~~, This ome shows will help you from start to finish in @ Unit sets 2 Special Service Pi oar Unit at a little inventive genius rigging up an indoor or outdoor joy wi r eit ral, pan. give you in the way of a safe ey p you will be matched against other Units. mpers range for rifle shooting. The plan : . ted - ‘amide he _ The W.J.R.C. gives you all the Get the official plan rente needs no explanation. The picture nroail ile Rete. etantehe: 4h oe instruction necessary to become a and handbook build- build P € range 18 tO real expert in the use of a rifle. It Of as a provides for officers, supervisors, eae eg 3 ay the Winteee. _— ) course, not ever Oy has a i itle Corps “Plan for organizing a W.J.R.C. ul for back yard or field hein he ah build ak sp cesesanneia pile if me oy "Like book é sail r (disk é : to handle a rifle safely.” is klet tells ( : such a range. For the city boy, a It costs you nothing to join the you all about the W.J.R.C. and describes in , fruit safe backstop for .22 shooting can z ip detail the fi ints of shooti acking nent ice iP gel gl” 8 pe W.J.R.C. There are no dues and no =a an Pe ne be rigged up in the cellar or attic. muittary obligations. Any boy orgirl if 290,46 bey scout, oF, member of er and a Sting hae gind ithe cand not over 18, who is in good standing ganization and ies the name ote official r; also Nob on in his or her community, is eligible. _ in charge. ie into 0 boy, no matter where he lives, Membership in the W.J.R.C. covers the National Head ‘ a need give up hope of getting in on entire United States. There is hardly a ; piper pool. | Winchester Junior Rifle Corps apt Standard types ph 3 caer liecags-ve it ap ete with members 275 Winchester Ave., New Haven, Conn., U.S.A. _ of the Winchester Junior Rifle Corps. Division 720 into a id the Winchester Junior Rifle Corps ade = ; National Headquarters, 275 Winchester Ave. WINCHESTER MODEL 90. Take-down Repeating .22 New Haven, Conn., U.S. A. Division 720 he car, my ope rifle, paca octagon barrel. The standard target ay rifle Jor over 20 years. entiemen: on om one register a 4 ius as a —— of st S, use of a memberahtip button and catidente of Mean ways. ship. Also tell me how to organize a Local of the Unit of the W.J.R.C. V truly yours, can be WINCHESTER Take-down .22 caliber single shot rifle. poe 3 made A low priced, light weight gun made in two sizes. meee t wait- FE eRe a ee ae wi ORPS Slreet AEP ESS ..nccenccncce cc cb cn no an nn ec awansss WINCHESTER JUNIOR RIFLE C tie ee eee National Headquarters, 275 Winchester Aveuue, New Haven, U. S. A. 87

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Popular Science M. onthly : - (Y O c ea OQ = oa c . fc U f 0 c E 0 Q 3 : v a = a e c Largest Manufacturers

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hly July, 1919 Where Strength Means Safety A storm-tossed sea—a giant liner crowded to the rails with panic-striken humanity—and the only thing between the rock bound cost and eternity—an ACCO CHAIN—and type of chain tester in the world. You can stake your last dollar that every link in each chain we make will HOLD for the purpose intended. And we make chains for every known requirement from Plumbers’ Safety . Chain to Ships’ Anchor Chain—all sizes, styles and finishes. RaQ SS ‘ OAS | COMPANY, Incorporated ’ CONN., U.S. A. 1 Co. Ltd. Niagara Falls, Ontario 'S of Chain in the World roe sit Nass 89

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Popular Science Monthly is,

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After the day, a plunge. and after the plunge. eool clean BV.D. BMD. quality ean only be obtained in BV.D Underwear

If it hasn't this Wevol It isn't B.V.D. Red Woven Label | sestpetait TRave Underwear (Trade Mark Reg US.Pat. Of and Foreign Countries)

B.V. D. Coat Cut Undershirts and Knee B.V. D. Sleeveless Closed Crotch Union Length Drawers, $1.00 the Garment. | Suits (Pat. U. S. A.) $1.75 the Suit. THE B.V.D. COMPANY, NEW YORK. Remember no underwear is B. V. D. unless it bears the B. V. D. Red Woven Label _ ae Serta

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El July, 1919 A Lathe Made from an Old Bicycle Why not pedal instead of using a hand crank ? ID you know that a complete lathe, upon which you can make all kinds of work, whether flat, cylin- drical, spherical, long or short pieces, can be made from odds and ends and an old bicycle? No? Well, here’s how it is done: First, a convenient space in the cel- lar or outhouse is selected, about 3 ft. in length, where a permanent stand can be erected. Two beams are fasten- ed to the ceiling and to the floor next to the wall. From these two sup- ports should project a table made of wood, about 2 by 1 in., which will be heavy enough if it is properly attached. Projecting 6 in. from the table proper are two beams upon which two 2-by-i-in. boards are fastened at equal distances from each other, all connections being made with screws. The two boards are the most impor- tant part of the lathe-bed, the rest of the table being utilized for tools or for unfinished work. The carriage is fastened to the front board with iron clamps, so that it can be moved to the place where it is needed. The head- By E. Bade _ This contrivance is an advantage over other kinds of power lathes for it is not so tiring and tail-stocks are fastened to the second board in a like manner. The head-stock consists of a wooden pul- ley fastened to an iron core which turns in a U-shaped bracket. The tail-stock, with the feed-screw, con- sists of a wooden frame upon which the axle of a bicycle is fastened. One ‘end is pointed so that it can engage the wood as it is turned. The feed- screw must be made movable, and this can be achieved by fastening one nut of the axle to the wooden support. . The back wheel of the bicycle is placed. under the wooden pulley of the head-stock and a suitable frame made, so that the bicycle wheel can be turned by means of the pedals. The. bicycle is braced by two wires on each side which must be pulled taut. Strong cord or thin rope will serve the purpose of a belt just as well as leather if it is spliced together. The desired tension can be given by moy- ing the frame of the bicycle forward or backward a little. A Gymnasium Apparatus for the Home ROBABLY the most abused piece of gymnastic apparatusis the paral- lel bars. Consequently, in building much care should be taken to build it with an eye towards strength as well as design. To be healthy one must first exercise. Here is an excellent way to become fit Use any suitable hard wood such as hard-pine or oak. Cut out one piece for the backbone 8 ft. 6 in. long, by 12 in. wide, by 2 in. thick. Round off A pair of parallel bars By L. B. Robbins the ends and bevel the edges. The two cross-pieces are then cut from the same stock, 4 ft. by 8 in. wide. These should be treated in the same way. Bolt them to the backbone so that their inside edges will measure ‘5 ft. 6 in. apart, using four bolts to each piece, countersinking them on the under sides, so as not to scratch the floor. A pair of iron floor flanges with a 2-in. opening should then be fastened to each cross-piece with lag screws. Place them equal distances from each end of the cross-pieces so that the inside faces of the pipe openings will be spaced 25 in. apart. Then pieces of leather glued to the under surfaces of the ends of thecross-pieces complete the base. Varnish them and set aside te dry. The posts are composed of 4 lengths of 2-in. galvanized pipe 4 ft. long. The bottom ends are threaded to screw into the flanges,’and T-pieces, which have been sawn in half length- wise along the horizontal part, are screwed to the top ends. The halves of the T’s which are left are then bored with four small holes, one at each cor- ner. Now, jam the bottom end of each post between two solid objects capable of withstanding the strain, and inserting an iron rod into the other end, exert enough pressure to slightly bend the pipe at the bottom end until they are of such a shape that with the 91 bottom ends screwed into the flanges’ the top ends of each pair will be just 18 in. apart. This will take consider- able strength and patience, but after it is done the rest is easy. Set them in proper position and hold them there by burring over a bit of the top of each flange with a cold chisel. When the posts are in place the fact that the T’s are off-set is obvious as the tops of the posts are now slanting in and the top edges of the T’s would do the same if they had not been sawed in half. As it is they will now carry the bars evenly. Making the apparatus requires only tools found in every home

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Popular Science Monthly A Home-Made Soldering-Iron Heater professionals, find occasional use for a soldering-iron, and if it is not the electrical kind it must be heated. ; A simple and inexpensive heater can easily be made to run on the 110-volt, 60-cycle alternating current which is generally supplied. You must first consider to what use the instrument is to be put, and make its size accordingly. . A jeweler using small coppers would not necessarily need as large a coil as a tinsmith, but in either case sufficient resistance wire must be used to pro- duce the required heat. The illustrations describe a heater that one experimenter made and used with very good results. It heats a \%- or 34-in. copper in a few minutes, or two small coppers may be heated at the same time. 58 At his tin-shop he made a sheet- iron tube with the regular stovepipe lick joint anywhere from 1 to 2 ins. in diameter and from 3 to 5 ins. in length, according to the size of heater under construction. At one end is a solid or closed head with a 3%- or %-in. flange. The open end may or may not have a flange, as the fire-clay to be used later can be made to take its place. Whether the coil is to be wound in a lathe or by hand, it is advisable to turn out a hard piece of wood some 2 ins. longer than the tube and of such size as to slip snugly into the tube. Drilling two small holes in the solid end of the tube and driving in tacks to hold it tightly on the wood core will prevent it turning in the shell during the winding. Next, wind a couple of sheets of mica over the iron tube for its entire length, and hold them in place tem- porarily by a string. In winding the coil any kind of resistance wire may be used, but one OY ectasiorals, nds as well as WOOD CORE HELD IN LATHE FOR WINDING Z 36 FLANGE TACKS = oy HOLD PORCELAIN TUBE AND STAND IN PLACE THEN PLASTER. OR FIRE CLAY IS Segn2nceS2555=>SSSS== TONOV.LINE PORCELAIN TOMO V.LINE LAMP CORD ij (SPOOL OF RESISTANCE WIRE A brief study of the above diagram will give an idea of the simplicity of design By W. E. Day of high resistance is far better if the proper length of wire is used. This kind requires less wire, besides taking up less space. No. 22 or 24 wire proves very satis- factory; and as there are dozens of kinds of resistance wire on the market, and as no two people in a hundred are interested in wire, I suggest the above numbers for reference in buying it. Obtain a smooth board 3 or 4 ft. long by 1 ft. wide. Screw small porce- lain knobs, say 2 or 3 ft. apart, length- wise, starting at A, winding the wire Easy to make and just as practical as the store article is this heater tightly back and forth, and allowing the spool end to come out at B. Connect one strand of the electric- light cord to A and hold the other strand at B. It will allow the so- called ‘“‘coil’’ to heat up, and more wire may be added or wire taken off this coil until it shows a dark red its entire length, which is the proper amount of wire to use. Don’t let the wire turn a white heat or it may melt and burn out the coil. No. 24 alloy resistance wire has about 1,300 ohms per 1,000 ft., while Nichrome of the same size has 1,485 and German-silver wire only 540. The length of wire may be calculated. in this way, but I have found that the testing-board above described is the safest and most satisfactory. In winding the coil, anywhere from 20 to 45 ft. of wire may be required, depending upon the resistance of the wire used, this being determined by experiment on the testing-board. Wind the turns of resistance wire tightly, about 1/16 in. apart, and if the required. length of wire will not wind upon one layer of the coil, put on another sheet of mica and wind as before. Remember that insulation in all the construction is absolutely essential. Assuming that the coil is wound, another sheet of mica is wound over it, being held in place by fine copper wire wound tightly about it to prevent the coil from loosening. Obtain from an electrical supply shop two porcelain insulating tubes about 14 in. in diame- 92 for ter, cut them down to 1 in. in length and wire them tightly to the coil, having previously soldered each terminal to the lead in the lamp-cord, so that the joints will be in the bottom end of the porcelain tube, as in S. In the same manner, fasten the brass trips “lower S” which support the coil upon the base and be very careful of all fastenings, so that they will not cut through the mica and short-circuit the coil. Ordinary stove lining clay may be used as a covering for the coil, plaster. ing a thick layer about the coil as wel] as the back end. Try to get it moderately smooth and even, and carefully dry it out a little at a time by turning on the current and then shutting it off again. This method will prevent cracking of the fire clay. The base may be made any suitable size and faced with a sheet of asbestog upon its top. The soldering-iron holder may be made for use with any length handle by using a square brass tube with a solid brass square rod sliding inside. This is held in any position by the thumb-nut. Using a Bit Depth-Gage as a Hook-Driver HE driving of hooks is a most un- pleasant task, unless the workman possesses one of the special screw-eye attachments sold for the purpose. If he hasn’t this device at hand, then the hooks must be driven by hand power, a slow and exasperating job, especially when a quantity of them must be driven. This trying work can be done easily This attachment turns the bit into a hook-driver which saves valuable time and in short order if the carpenter owns one of the widely used inter- locking bit depth-gages sold for regu- lating the depth of auger holes. To use the depth-gage for hook driving, all that is necessary is to clamp it to the front end of one of the smaller sizes of bits. The device should set up so as to protrude about three quarters of an inch beyond the point of the bit. This leaves the two flanges free and makes a slot of just the proper size and shape to catch hold of the elbow portion of the screw hook. Hooks can thus-be driven with the same speed as screws.. The flanges of the depth-gage hold the hook securely driving, yet are released im- mediately as soon as the driving is done.—HENRY SIMON.

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ith a side, y the --< oo" ae yenter inter- regu- hook is to of the levice about d the e two st the old of 0k. sh the ges of curely 1 im- ing is

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July, 1919 . Interchangeable Type-Sets For Every Language Every Business, Every Science and Every Profession No Other Typewriter Can Do This: Make Your

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Writing T7-a-l-k Just as oratory puts the power of emphasis into the spoken word, so the— Multiplex Hammond —puts the all-telling power of emphasis into the written word. No other typewriter can turn cold type into living, absolute correctness —in business, professional or breathing words—words pulsating with the writer's Soctal usage. deepest convictions—words expressing to a nicety Note the several distinctly different type-styles his most conventional mood—words showing always reproduced below—‘‘Just turn the knob’’ to change: All Type Styles ~ All Languages ~ All Sciences especially represented on” one, MULTIPLEX CHANGE TYPE 7N A SECOND FOR_BUSINESS BXECUTIVES: — Miniature Type and close spacing for condensing Loose-leaf. Manuals and Index Card, work The Multiplex is un-like any other type- Mail the Coupon for FREE BOOKLET

writer. Its work is as great an improvement over the typewriter as the earlier typewriter was over the fountain pen, or the fountain pen over the quill. There are over 365 different type- sets, including all languages, to select from. Mail tnis Coupon NOW sd 7 Name

It will show you how, with the Multiplex, you can put the force of emphasis into your typed matter—how you can drive home with strength of accent the fulness of your argument— how you can write with the same convincing force that you use in Re = exclusive feature of the Multiplex. _ We will also send our pamphlet, “The President and His Typewrtter.” ©. HAMMOND TYPEWRITER CO., 639 East 69th St., New York City Gentlemen: Please send Free Booklets to

*%, ‘ Many Typewriters in One”

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and many languages. 93 Inquire about special terms to professionals

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] <f f ee Seoe Geeece ee iene a aga

DR GEE SE

A new-engined Harley-David- son! Fully one hundred pounds lighter, quieter, snappier than any solo mount you have ever seen before. Powered with a balanced horizontal-twin en- gine—almost vibrationless and wonderfully “peppy.” All the speed you want—and it hugs the road ! Here are a few of its exclusive advantages: Unit power plant, single drive chain, fully en- closed and automatically lubri- etek Se eee ee

he ame ae en oa Ee eae ee ae ig a Rs THE NEWEST HARLEY-DAVIDSON HARLEY-DAVIDSON MOTOR CO. _ MILWAUKEE, WIS.

cated ; low center of gravity and low saddle position; great range of power, amazing pick- up and low-speed perform- ance, due to perfect balance and super-heated intake mani- fold. You cannot appreciate this Harley-Davidson Sport Model or realize its great superiority without seeing it in action.

Ask your dealer for a demon- stration. Then you'll know. Do it today. Si i rs tania si “ ¢

ARMATURE AND MAGNET WINDING By Horstman & Tousley A necessary book for electricians. Full facts and diagrams, $1.50 postpaid. Popular Science Monthly, 225 W. 39th St., New York 10,000 Miles \Guaranteed and No Punctures

sr ten years test by thou- nds of car users, Bricteon Pn Sener ig Pye Ne matio ti 59 ———. ee we details of most liberal, con ava Bree Trial plan ever e! The Brictson Mfg. Co. Dept. 134- 770 W.0. W. Bidg., Omaha, Nebr.

THE BOY ELECTRICIAN Practical Plans of Electrical Apparatus for Work * and Play with an Explanation of the Principles of Every-day Electricity. $2.00 Postpaid. POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York THE ANDERSON STEAM VULCANIZER We manufacture them. We own and teach you the Anderson Method of Vulcanizing, 90% profit And still you gaarantee your work to / a balance of the tire and collect E Fay 4 Reeratare ont location 4 ;

of you or refund you! Our course will cont you 320 ‘in either the day - eos classes and any time thereafter be refunded us for a Salonminer. your — in cash 0 days in Any Anderson State school of ebendeing will start youin this most profitable business. se print your name.

We receive many we can not make out.

94 Popular Science M. onthly : An Inexpensive Smoke-House for the Farm M®*: whether cured in brine or by the dry method, will keep better, and have a great deal better flavor, if it is smoked. This may be done in a makeshift shanty, or even in a drygoods box. Or, it may be done in a small house of wood or concrete built for the purpose, if there is enough meat to warrant its erection. However, meat that is sub- jected to a direct heat is apt to absorb odors and to become partially cooked, causing the wey to vary.

The smoke travels up through the pipe into the smoke-house where the meat is hung To obviate this a smoke-house similar to the one shown in the illustration was built. The combus- tion chamber proper is at some dis- tance from the smoke room so that only dry smoke reaches the meat, with the result that the meat is both well smoked and dried. The combustion chamber’ was erected upon a hillside, as shown, so that the smoke readily reached the smoke room by natural draft. It was of concrete and was made by dig- ging into the bank so that a wood box about 2 ft. square could be set in, with 3 or 4 in. to spare on all sides. The space was then filled with con- crete, forms being used where neces- sary, and a door made in the front at the bottom, about 10 in. square. The roof was made thicker than the sides and covered with earth. Lengths of drainpipe were laid to connect the combustion chamber with the smoke-house, the first section of the pipe being laid in the soft concrete. In the illustration the pipe is laid beneath the surface, but this is not necessary as long as the joints are tight, to prevent the escape of smoke. Over the upper end of the flue, a small house, 4 ft. square was built, with braces and beams upon which to hang the meat. Ideas differ as to the best kind of fuel. Corn cobs are good, so is any dry, non-resinous wood. Coal would taint the meat.— DALE R. VAN HORN.

ON, BE eae

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into ung use the yUSs- dis- hat oat, oth was $0 the was dig- ood ; im des. -on- ces- t at The ides | to vith 1 of ete. laid not are oke. mall vith ang 1 of any ould RN.

cat NAILS NE

July, 1919

WIL, ae loll Ge Jala 44

ire

hanks to the American Navy Lhe air road to F urope Is open: Ss Qt e ses WWeSss|=

—— a ———> —— = S SSIES — ROMS RES = ae REE = linia 2 aA iil AAU CURTISS AEROPLANE AND MOTOR CORPORATION, Sales Office: VANDERBILT AvE., NEw York CIty CURTISS ENGINEERING CORPORATION, Garden City, Long Island THE BURGESS COMPANY, Marblehead, Mass.

< RCN

Aircraft Association 95

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Popular Science Monthly, An Instrument Shelf for the Drawing-Table F \poiamued for holding drawing ip. struments, ink, and so forth in a convenient, level position can be easily made with a few pieces of wood some screws, and two hinges. . Smooth up a piece of board about 10 in. by 12 in., another piece of board about 114 by 15 in. and a narrow strip of wood about 10 in. by 1 in. Cut a 4-in. slot through the center of the narrow strip to about 11 in, THUMBNUT nef | : TWO HINGES natn ar ees ELS a MRCS RE STEEN ~ Fi t iy EES >, | 112" aera" r Vy We Back This Trademark Z2 a hed With Our Reputation Scanian antes op apced sp-tin coat YOU can point with pride and satisfaction to the from each end. In one of these ends RistiDRade trademark on your bicycle. drill a hole large enough to allow a l4-in. wood screw to turn freely in it. The diagram shows a back view of * We back this trademark with our reputation..You will find the shelf and indicates how it is to be it on all Davis-Made products. Dayton Bicycles deserve and assembled. First, screw the hinges to bear this symbol. Our new catalog tells in detail about these one end of A and one side of B, so fine bicycles. Write for Catalog B-11 and see the Dayton at that when the projecting edge of B your dealet's. is screwed to the under side of the 7 -| drawing table the board will form a Cycle Dept., THE DAVIS SEWING MACHINE co., Daytcn, Ohio shelf that can be adjusted at will and to any level. The proper level is maintained by means of the narrow slotted strip and the clamp screw. A small drawer attached to the table will greatly increase its useful- ness.—FRANK L. MATTER. It is a mark of distinction and quality—and is so recognized. Poor Contact Will Impair Battery Efficiency OTORISTS are sometimes at a loss to understand why the bat- tery runs down so quickly. When i ne Sea trouble of this sort arises, it will be ee Retall » | well to carefully examine the brushes Our Sundry Dept. offers Needles 39c. per thousand, {(()\)} on the starting motor. The storage WE PAY $7.00 TO $9.60 A PAIR AND EX- 3 in lots of 500,000. Motors $1.35 to $14.75 each. Tone Hib i 4 press charges. BIG PROFITS. We fur- Arins and Reproducers $1.30 to $5.75 per set, Main battery supplies current through ‘uaranteed h grade stock and . Springs 20c. to 90c, each. Records, Needles, Sap- z Duy all you raise. Use back yard, phire Points and Parts at reasonable prices. brushes to the starting motor, and it barn, cellar, attic. Contract and graphic Parts, ' Write f 84 page catalogue, the only one of its . : Illustrated Catalogue Free. kindin America, illustrating 33 different styles of sometimes happens that these brushes STANDARD FOOD & FUR ASSOCIATION y Talking Machines and over 500 different Phonoe } are not making proper contact. This causes more or less failure of the sys- tem and often results in the rapid running-down of the storage battery. The remedy for this condition is quite obvious, once the cause has been found. A partially run-down cell connected up with good ones in the system will cause the others to do more work than they are able to handle. Thus the’ efficiency of the whole battery will be very much impaired, as the cells will run down more quickly than 45) they will under ordinary normal es conditions. It is a gvod plan to MANHATTAN ELECTRICAL SUPPLY COMPANY, In poi th o ° tighten all connections at least once NEW YORK, 17 Park Place CHICAGO, 114 So. Wells St. ST. LOUIS, 1106 Pine St. SAN FRANCISCO, 604 Mission St. a week.—PETER CLUTE. 397 C. Broadway 38 33 LUCKY 13 PHONOGRAPH COMPANY Export Dept. 46G, E. 12th St., N.Y., U.S.A. 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 work. ; ASK YOUR DEALER Send for Our New Edition of Our Catalog A28 It will be pocket size, 8 x 414. and wil! 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 Clocks, Medical Batteries, Motor Boat Horns, Electrically Heated Apparatus, Battery Con- ——. Switches. Battery Gauges, Wireless Telegraph Instruments, Ignition upplies, etc. $6

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. in, T Up g- ut ands Wa eely v of 0 be s to » 80 f B the ma and 1 by strip the oful- at a bat- Then 1 be shes rage ugh 1d it - shes This sys- apid cery. juite been cted will than the ° will cells than rmal 1 to once July, 1919 What Car Owners Say “You are at liberty to use the letters I wrote you, for the Dillon lenses have no equal in my estimation, and I have tried several others that are on the market. Yours only have given me just what I have been expecting of the others.”’ J. E. Cavey, Stratton, Col. “Received the Dillon Lens and had same installed on my machine in less than five minutes. Have tried them out on the boulevards, also on the country roads, and must say that they are in my opinion the perfection of lenses. Have tried several other kinds of headlight attachments, but your lenses are the only ones that have given me a perfect and clear light.” Jas. A. CooGan, Kansas City, Mo. “T have found in the Dillon Multi- Vision Lens, at last, comfort in night driving. I have tried almost every other kind of headlight attachment on the market, but they are excuses com- pared to the Dillon. I wouldn’t sell mine for $25 if I couldn’t get another air.” : J. MaxiM_E Roy, Broussard, La. “They are all that you claimed them to be and then some. Would not drive over country roads without them. They give a wonderful light right where you want it.” C. E. Markuam, Detroit, Mich. “The Dillon lenses are the finest auto lenses I ever rode behind, and ap- parently perfect. Am very much pleased.’’ E. N. EEASONER, Oneco, Fla. ._ “I had the extreme hard luck of breaking one of my Dillon lenses. Would just as soon have broken a con- necting rod, because I am at a loss without it, and cannot replace the Dillon with any other type of lens with the same satisfaction.” E. H. KELLER, JR., Fort Worth, Tex. per Pair ny = Ze N ere DUS: ' MULTI VISION Do You Feel Safe When Driving at Night? You may have felt that all legal lenses cut down the light and are there- fore not to be considered unless under compulsion of the law. The Dillon Multi-Vision Lens is different. It gives you more illumination on the road than plain glass lenses, and is legal in all States. : You see the ditches and the entire roadway in almost daylight clear- ness. There are no dark areas, no “‘waves of light,’’ no shadows. Just a fine, full illumination that leaps straight out at both sides and extends far ahead. One short ride behind the Dillon Lens on a dark night will give you proof beyond question of its superior lighting efficiency. As driver or as passenger you will realize immediately that here at last is a lens that satisfies every desire for light, safety and compliance with the law. Read the testimonials in the opposite column. They are typical of the thousands of letters we have received, all telling the same story of more and safer light. . The Dillon Lens gives more light with bulbs of lower candlepower than any other headlight device in the world. Get a pair from your dealer today. Try them out and if not fully satisfied, return them and your money will be refunded. If your dealer can’t supply you, order direct. Same price, $3.50 per pair, any size, postpaid. Booklet upon request. DILLON LENS & MFG. CO., Dept. “B,’? Wheeling, W. Va. DEALERS AND JOBBERS CAN BE SUPPLIED PROMPTLY BY PITTSBURGH PLATE GLASS COMPANY Atlanta, Ga. Cleveland, Ohio Great Falls, Mont. Minneapolis, Minn. Pittsburgh, Pa. Baltimore, Md. Columbus, Ohio Highpoint, N. C. Newark, N. J. Rochester, N. Y. Birmingham, Ala. Dallas, Texas Houston, Texas New Orleans, La. Savannah, Ga. Boston, Mass. Davenport, Iowa Jacksonville, Fla. New York, N. Y. San Antonio, Tex. Brooklyn, N. Y. Denver, Colo. Kansas City, Mo. Oklahoma City, OklJa. St. Louis, Mo. Buffalo, N. Y. Des Moines, Iowa Memphis, Tenn. Omaha, Nebr. St. Paul, Minn, Chicago, Il). Detroit, Mich. Milwaukee, Wis. Philadelphia, Pa. Toledo, Ohio Cincinnati, Ohio Grand Rapids, Mich. Pacific Coast States Western Canada PATTON PAINT COMPANY INDEPENDENT ELECTRIC CO., Regina, Sask. i m Cal. San seems nae Angeles, Cal Repost Memes ? nd . Timms, Cress & Co., Portland Ore. J. J. NORDMAN & CO., Pittsburgh, Pa. 97

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y should your wife dothisi¢ when Kor-Ker TIRE TREATMENT would have sealed the puncture in- stantly without the slightest loss of air. There would have been no de- lay—no danger—no dirty hard work —no weakening. of the tire casing. For seven years and in forty different countries thousands of autoists have enjoying the luxury of riding free from the worry and care of punctures, because their tires were KOR-KERIZED, and yet to many autoists the fact that KOR-KER absolutely seals punctures and stops slow leaks seems too good to be true. KOR-KER is a rubber preservative. Pre- serves your tubes and casings. _KOR-KER is not a tire filler—occupies but little space. KOR-KER doubles life of inner tubes. Tubes can be changed from one casing to another. KOR-KER reduces blowouts to a minimum by keeping tires at normal inflation, whereby at least 90% of tire troubles are prevented. Remember that KOR-KER preserves rubber. We stand back of all the above statements—they are facts that can be easily substantiated. If you cannot readily find the KOR-KER dealer in your town, write us for his name, and convincing literature. ALCEMO MFG. C0. / Sb» 6 Bridge Street, Newark, N. J. (SN Also Mfegrs. of the Klearsight Windshield ~ a Wz 98 Popular Science M. onthly Provide Your Trunk with a Tray Lock SECONDARY trunk lock is a}. ways valuable, and especially go to those who possess only one room, for with this attachment one may keep Y TRAY. LONG 1/8" BOLTS KEY ae it FRONT VIEW OF TRAY The petty thief cannot get into your trunk if you provide it with this tray lock valuables securely locked underneath the trunk tray, irrespective of the regu- lar lock on the trunk. The above drawing shows the man- ner in which a secondary lock is con- structed. Connections are made be- tween the tray and its ends. The two cross-pieces are made from spruce 2% by 3% in. in width. Special Y-in. bolts connect these to the tray. At one end two pieces of iron are bolted to a cross-piece, with 5% in. of each piece projecting, to slide under the end supports. These pieces can be filed from an ordinary strap hinge and fastened to the cross-piece with 5/32- in. stove-bolts. At the other end two drawer locks are fastened to the cross- pieces. After turning the keys in these locks their catches project into the end support and form a substan- tial lock. The bottom is specially re- inforced, as this method makes it still more difficult to gain an entrance.— M. A. WISE. Transforming an Old File into a Reamer VERY handy tool for the amateur is a tapered reamer. This can be made from a medium-sized round file. The temper is first drawn by ailowing it to get red hot and then gradually cooling it off. It is then ground on an emery wheel to the shape shown in the illustration, and driven into a file or chisel handle. Holes are very often drilled too small or slightly out of line. With this reamer you can enlarge the hole by END vicw If the file is of thick material it should be filed up on both sides turning the reamer completely around. If the hole is to be lengthened the reamer is turned only half way around and back again.— WALTER B. WEBER.

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ko om ial ay. ed ich the be nd 32- wo in nto an- till eur 1 be file. ing ally | an the. . or nall this by ind. the und BER. If Engines Had Windows if they were made of glass you would understand why it is hard for most cars to start, why the cylinders and other parts must “warm up” before there is anything like smooth running, why I automobile engines had windows or gasoline works down into the crankcase and “cuts” the lubricating oil, why you have to take the car to the service station so often for repairs. Through the window you would see at once that most engines of today cannot burn the so-called gasoline that is fed to them. Gasoline is a mixture of light easily vaporized constituents and heavy kero- sene-like constituents. There is not enough light gasoline for all the cars in use. It must be blended with kerosene- like fuels which the engines of today were never intended to burn. That explains why in starting only the lighter parts of the fuel—the real gaso- line—is vaporized and why the heaviet part cannot be consumed until the engine warms up. And even then drops of kerosene-like fuel collect in the manifold and are swept into the cylinder where they work down into the lubricating oil and destroy the very properties that make it useful. There is only one way out of the difficulty—to build an engine that will burn every drop of fuel, extract the last thermal unit of power out of it, so that you get all the mileage to which you are entitled and sv that your repair bills will be reduced. The Chalmers engineers have built that engine. It is adapted to the fuels of the day because it has two distinctive features. One of these is the Hot- Spot manifold; the other the Ram’s-horn shape of the manifold. What is the Hot-Spot? Part of the exhaust heat of the engine is made to heat that part of the mani- fold which is struck by the jet of mixed gasoline vapor sprayed by the carburetor. Immediately the Hot-Spot vaporizes the drop of fuel by which it is struck. Only the right mixture of vapor and air is supplied to the engine. At once all your starting difficulties disappear. In thirty seconds the engine is running perfectly. And no raw gasoline finds its way into the lubricat- ing oil down in the crankcase. The Ram’s-horn manifold completes the work of the Hot-Spot. It supplies all the cylinders with an equal amount of mixture. And it does this because it has no corners, no sharp angles to check the flow and because the inner wall is smooth. In most engines the manifold supplies mixture to one cylinder from which the surplus passes to another. Thus the mixture overflows from one cyl- inder to another. The sixth cvlinder gets either very little mixture or raw drops of unvaporized gasoline. The Ram’s-horn supplies all cylinders with the right kind of mixture in the right amount. That.explains why Chal- mers engines run so smooth- ly, why they are so cool on ; a warm day, why they are so efficient. Qua This is the third of a series of six bul- letins in which the wonderful features of the new Chalmers will be explained. Lo

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Using DOUBLE Ratchet adjustment ina The owner of a “YAN- KEE” Ratchet Hand Drill No. 1530 comes to regard it with a pride that is close to fulfriend. With its five different adjustments you can do work you’d never think of attempt- ing with any drill but a “YANKEE.” Think of the pos- ™ sibilities ofthe DOUBLE Ratchet in a cramped space. Thé slightest move- ment of the crank in either direction gives continuous forward drive, and drills as rapidly as if a full turn of the crank could be made. Note the five adjust- ments of Ratchet Shifter between small gears. Set in the upper notch and you have a plain geared drill; in the second notch, it becomes a Left- hand Ratchet drill; in the third notch, a Right- hand Ratchet drill; in the fourth notch it isa oT RATCHET drill. With the shifter in the fifth (or lower notch), the gears are locked for opening or closing the chuck. “YANKEE” Ratchet Hand-Drill No. 1530 Lengths 10)4 in. Price, $3.90 YOUR DEALER CAN SUPPLY YOU Write for free**‘YANKEE” Tool Book, showing “YANKEE”"’ Tools in action and illustrating better ways of drilling, boring, tapping, and driv- ing and drawing screws. Weight, 20 oz. NORTH BROS. MFG. CO. PHILADELPHIA the affection felt for.a faith-’ ‘Popular Science Monthly © How to Build a Concrete Milk-Cooling Tank By S. R. Winters HETHER milk is produced in the frigid climate of Maine or in the warm climate of North Carolina, ice is a factor in retaining the sweet- ness of the products in the creamery. A liberal use of ice not only insures a wholesome product but will curb the development of bacteria. New England; as well as Southern, dairymen squander thousands of dol- lars annually because of poorly cooled milk and cream. Since 85 per cent of all milk and cream sold from farms in the United States is produced where natural ice is available, it is only a question of methods, in cooling, storing and shipping milk. Hence, an in- sulated concrete tank, as described herewith, is not only satisfactory but is inexpensive, as it can be equipped within the farmer’s own domain. The walls of the tank should have .a total thickness of from 8 to 10 in. The outer shell should be a 2 to 4-in. wall of concrete. Next to this is placed a 2-in. layer of insulating ma- terial and then an inside concrete wall of 4 in. thickness. Here is the proper mixture for the concrete: one part Portland cement, two parts of clean, sharp sand, and four parts broken stoneorgravel. Hydrated lime, equal to 10 per cent by weight of the cement, should be added to the mixture for the purpose of making the tank waterproof. Construct the outer wall first, then set the insulation in hot | asphalt or gas-house tar and coat its inner surface with the same material. Permit the substance to dry thoroughly before the inner wall of concrete is built. The inside wall of the tank should be carefully troweled so as to force back all projecting particles of stone or gravel. When constructing the tank, if built partly underground, as described in the WOOD CURB ~ _ SPIKES SET IN. CEMENT OUTER WALL INSULATION INNER. WALL Tt Inexpensive to build, cement form- ing the greatest part of this tank illustrations, an outside form extending only from the surface of the ground to the top of the tank is necessary. How- ever, when the tank is constructed altogether above ground, a complete outside form is essential. After the outside forms are in position pour 4 ins. of concrete into the bottom. On this concrete set the inside form, leaving a 100 space of from 2 to 4 ins. between the forms, depending on the thickness of the outside walls. After the concrete has set, remove the inside form and coat the inside walls and floor with hot asphalt or tar. The sheets of insulation should be coated with the same material and put in place on the floor and against the walls, care being taken to make all joints tight. After the insulation is in place cut down the inside forms, previously The completed tank is shown in de- tail in the cutaway illustration above used, to a size that will provide a 4-in. space between the walls and forms. The form should be set into place and blocked up 4 in. above the floor, and the concrete for the inner walls and floor should be poured in at one operation. The wooden curb around the top of the tank should have twenty penny spikes driven into the underside at frequent intervals and the curb set in place and pressed down so as to embed the spikes into the concrete before it sets. If the inner surface of the walls is rough upon removal of the forms, a coat of cement mortar should be applied. The size of the tank should be gauged by the output of milk on the farm. With the flow of milk varying from season to season and from year to year, the construction of a tank in two parts is suggested, the larger being approximately twice the size of the smaller. The cooling tank not only retains the sweetness of the cream but protects the product from dust, flies and other contaminating influences. The milk house is the best loca- tion for the tank and 50 degrees Fahrenheit, or below, is the desirable temperature. A can of cream placed in ice water in such a tank will remain sweet for several days, while milk will keep for a much longer time. On a structure of this kind depends the dairyman’s success. tills 5 ND te

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n the Ss of crete l and with ts of h the n the being e cut ously 1 4-in. forms, ‘e and r, and s and t one round wenty erside rb set as to nerete ace of of the hould ld be n the irying ear to n two being f the only mn but , flies onces. loca- grees irable water ot for op for icture man’s July, 1919 CARBON PROOF— Notice the sharp knife-edged porcelain in the crosssection of the AC Carbon Proof Plug here illustrated. That construction is the whole secret of this plug’s success. These edges, being thin, heat rapidly. The heat burns off the carbon as fast as it forms. This is an exclusive AC design and fully covered by our design. The Standard Spark TP dee /I\\N Plug of A merica more power—less gas Put a Set of AC Carbon Proof Plugs in your Ford, Overland, Studebaker orTractor—They Clean Themselves Equip your car or tractor with a full set of AC Carbon Proof Spark Plugs, and do away with all your carbon troubles. Thebetter quality of porcelain in these plugs stops breakage and current leakage. Consequently, a bigger, hot- ter spark is delivered, which makes your motor run more smoothly, stops its missing, and makes it quicker on the pick-up. With a set of these Carbon Proof Plugs in your car, you may advance the spark all the way without the motor knocking. Thus with a smaller throttle opening you get more power, better performance, and lower gasoline consumption. AC Carbon Proof Spark Plugs are specially designed for Overland, Ford and Studebaker cars. They are also built for tractors. Install a set of these plugs today. They cost no more than ordinary spark plugs. No matter what car you drive, there is an AC Spark Plug specially de- signed for it. Glance through the list of manufacturers below. _ They have been using AC Plugs for stand- ard factory equipment for years. During the war all Liberty and Hispano-Suiza airplane motors were equipped with AC Spark Plugs. You may be sure that the spark plugs which best served such masters will serve you best also. Write for The Spark Plug Story. It contains information that will prove of much value for you. Champion Ignition Company, FLINT, ¢«ACichigan These manufacturers use AC Spark Plugs for factory equipment Acme Trucks Delco-Light Kleiber Trucks Old Reliable Seneca Advance-Rumely Diamond T Trucks Klemm Trucks Trucks Signal Trucks a Bs cacy =m pore Ig te Knot. cunceurs Oldsmobile Singer rens Fox Dodge Brothers - rucks Wee Wenaies eee Packard Smith MotorWheel La Crosse Tractors Paige American- DuesenbergMotors Lalley-Light Standard Trucks La France Eagle Tractors Lane Trucks Pan-American Stearns-Knight Anderson Essex Liberty Paterson Sterling Motors Apperson Federal Trucks Liberty Aircraft Patriot Trucks Sterling Trucks Appleton Tractors F-W-D Trucks Metors Peerless Stewart Trucks Avery Tractors Gabriel Trucks bile Phianna Straubel Engines srockway Trucks Genco tiene Marmon Pierce-Arrow Stutz suffale Motors G. B.S. Motors Master Trucks lot Sullivan Trucks Sugatti G. M. C. Trucks Maxim Fire Trucks Pioneer Tractors Swartz Lighti suick Gramm-Bernstein Maytag Premier ‘Plants — Cadillac Trucks cLaughlin(Canada) Reo : J. I. Case T.M. Co. Hall Trucks MenomineeTrucks Re Vese Titan Trucks Chalmers Harvey Trucks Midland Trucks Riker Trucks Tower Trucks Chandler . latfield Mitchell Robinson Fire Universal Trucks Chevrolet Haynes oline-Knight : Trucks United States Chicago Trucks erschell- oreland Trucks Rock Falis Motor Trucks Cule Spillman apol Trucks Rowe Trucks Vim Trucks Commonwealth ispano-Suiza Nash Rutenber Motors Ward La France Conestoga Trucks owell Tractors ational Samson Tractors Trucks Continental Hudson elson Sandow Trucks Westcott otors upmobile 1 & LeMoon Saxon White Crane-Simplex Jackson Trucks Scripps-Booth Whitney Tractors Daniels Jordan Netco Trucks Scripps Motors Wilcox Trux vis Jumbo Trucks Northway Seagrave Fire Wisconsin Motors Deere Tractors Kissel Kar Oakland Trucks Wolv U.S. Pat. No. 1,135,727, April 13, 1915, U. S. Pat. No. 1,216,139, Feb. 13, 1917, Other Patents Pending 101]

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LTHOUGH the old-fashioned Fourth of July celebration with commercial fireworks has been largely banned, there is no reason why even greater fun should not be had with pyrotechnic materials prepared in the home laboratory. All the ‘fire and thunder, that formerly punctuated the outbursts of youthful patriotism on this red-letter holiday, may still be THISTLE TUBE ‘SY ——> RUDDER STOPPER} POTASSIUM CHLORATE AND MANGANESE RUBBER HOSE cn ae ies. P| HYDROGEN GENERATOR This mixture ignites with a loud report; ~ and very considerable shattering force enjoyed, and at the same time valuable . chemical information may be acquired. Note that in carrying out the experi- ments here described the utmost care must be exercised. Phosphorus and Potassium Chlorate To start your celebration with the proper amount of noise, the following demonstration will provide the ammu- nition. Place on a brick or anvil a very little powdered potassium chlorate (as much as you can get on the point of a penknife). Then pour over this one or two drops of a strong solution of yellow phosphorus in carbon di- sulphide. When the carbon disulphide . has evaporated, leaving phosphorus in a finely divided state throughout the potassium chlorate, a very sharp explosion will result. Should the ex- plosion be slow in coming, strike the mass with a hammer held in the gloved hand; but do not, under any circum- stances, touch it with the fingers. To make the solution of phosphorus, transfer, by means of pincers, a piece of phosphorus about the size of a pea to a small stoppered bottle containing a few cubic centimenters of carbon di- sulphide, and shake for a few moments. Always keep phosphorus in water, and never touch it with the fingers unless it is underneath water. To cut it, place the stick in a basin of water and use a sharp knife. Spontaneous Combustion Pour a little of the solution of phosphorus in carbon disulphide, used in the previous demonstration, over a piece of absorbent paper, and taking it in the fingers wave the paper back and forth through the air for a few minutes. As soon as the carbon di- sulphide has evaporated the phos- phorus will ignite and the paper will burst into flame. Old-Fashioned Gunpowder Mix thoroughly 30 grams of finely powdered potassium nitrate with 5 grams each of powdered charcoal and flowers of sulphur. Place the mixture on a square of asbestos and ignite with a long wax taper. A Small Cannon A cannon can easily be made in accordance with the accompanying diagram. Secure an 8-inch length of heavy glass tubing, about one half inch in diameter, and fit the ends with solid cork or rubber stoppers. The butt- end stopper should fit a little, more tightly than that at the muzzle, and, passing about it so as to be buried in the powder, in- sert a short loop of fine No. 28 iron wire. In the tube placea half-inch layer of gunpowder, and tamp it down with paper wad- ding. Connect the ends of the iron wire with a key and half a Only a harmless | | | | flash issues from this instrument, ; and it can be made to appear like its big brother if properly dressed 102 W. Darrow ae Popular Science Monthly _ . dozen dry-cells. Then clamp the tube and contents securely to an upright support, and press the key. The elec. tric current will heat the iron wire to incandescence and ignite the powder, If carried out at night or in a dark. ened roon, a brilliant flash of light wil] fill the tube and issue from its mouth, Touch-Paper For use as fuses in several of the succeeding experiments a quantity of touch-paper will be desirable. Thig can be made by saturating strips of unsized paper in a concentrated solu- tion of potassium nitrate and allowing them to dry. When ignited the com- bustion will slowly proceed until the whole paper is consumed and the fire cannot be extinguished by blowing. Red Fire - Finely powder one gram of potas- sium chlorate and eleven grams of strontium nitrate separately. (They must not be pow- dered together), TOUCH a, Then make a de MIXTURE mixture of the i chlorate and ni- trate together with 4 grams of flowers of sul- phurand 14 gram of lamp black. Place the mix- ture on an asbes- tos card board or paper and ig- nite with a long wax taper or by inserting in the heap a fuse of touch-paper. An in- tensely red flame results and one of great brilliancy in a darkened room. sa ASBESTOS CARDBOARD | #28 IRON WIRE COPPER WIRE ASBESTOS TUL COVERED BOARD You cannot blow out this flame, once it is started Green Fire Mix as before 3 grams of finely powdered potassium chlorate, 8 grams of finely powdered barium nitrate and 3 grams of flowers of sulphur. Place the mixture on asbestos and ignite with a taper or short fuse of touch- paper. Purple Fire Finely powder and then mix 2 grams of copper sulphate, 214 grams of flowers of sulphur and 15 grams of potassium chlorate. Ignite on asbes- tos with touch-paper or taper. White Fire Mix equal quantities of powdered potassium chlorate and magnesium dust. Place the mixture on asbestos and ignite with a long taper. Do not try to light it with a match. An instantaneous flash of dazzling bril- liancy results.

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‘ube ight lec. e to der, ark. uth, the y of This S of olu- ving Om- the fire tas- 3 of "hey URE | VIRE rted in- 2 of om. 1ely ams and lace nite ich- 1ms of of eg- red um tos not An ener seen Asie 8 86S ARSON B ESSN NNR A SOCTEBRI OA EN A * July, 1919 The date on the Film In just a few years you will ask: This picture of John, was it made before or after the war? And this of little Mary taking her first toddling steps—how old was she then? How those snap-shots, made on our trip to.the Yellowstone bring it-all back to us, except the date, —when did we go? Grandmother before the fireplace with her knitting, growing old gently and gracefully —how old was she? It is so annoying not to remember. Time plays the mischief with memory — but with the daze on the film you may laugh at his tricks. All folding Kodaks and folding Brownies are now autographic and, with autographic film, provide the means for dating and titling each negative as you make it. It is all done in a few seconds, is as simple as “‘ pressing the button”? and though it may not seem so at the moment, a daze is always worth while. And there is no extra charge for autographic film. EASTMAN KODAK COMPANY Kodak catalog free at your dealers or Rochester, N. i, The Kodak City by mail,

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FIT YOURSELF FOR THE BIG JOB Don't partate any longer. ‘There is a greater demand trained men now than ever before— greater opportuni ties—bigger pay—more rapid ad- Vancement. It's training that counts now—accurate knowledge—a complete grasp of your trade. Drake’s waist! Books FOR HOME STUDY pave the way to the fat pay en- a Written in non-technical language that any grasp. Send the price of any book listed below. an we will send the books postpaid—you keep them five days—if not entirely porated return the books and your money will be refunded in full. AUTOMOBILE BOOKS Brookes’ Automobile 1919 edi AUTOMOBILE IGNITION mis Redieiciepeernennpniens Automobile Ignition. y H. P. Manily. ket si eatherettc . $2 00 Automobile Star g and Lightin aly. vt 9 ae wee thew nd Ze $1. 50 ‘The Ford Motor Car and Truck and Tractor ttachments y Manly. therette . $1.50 erette . . . $1.25 Practical Gas and Oil n nen o. Handbook. rooke: Pocket size Te $1.50 gna Farming nd Traction Engineering. $1.50 ELECTRICAL BOOKS Electric Motors, Direct and Alternating Cloth $1,00. — $1.50 Wiring Diagrams and Descriptio $100. Leatherette $1.60 Armature and Magnet Windin ng oth $1.00, Leatherette $1.50 Modern Electrical Construction th $1.00, Leatherette $1.50 . STEAM ENGINEERING Swingle’s Handbook for Steam Engineers and Electricians ............... Cloth $8.00 Complete Examination Questions and Answers for Marine and Stationary NEL) o's 6 5.whs we04s 0's Leatherette $2.00 RAILWAY BOOKS Locomotive Engineering....... Leatherette $8.00 Locomotive Engine Breakdowns, with Questions and Answers . .. . Leatherette $2.00 First, Second and Third Standard Exam- ination Questions and Answers for Locomotive Firemen....... Leatherette $2.00 SHOP PRACTICE BOOKS Sheet Metal Workers’ Manual. : Leatherette $2.00 Sheet Metal Work and Pattern Draftin ae ‘ Slot p Oxy Acetylene Welding : and Cuttin , Leatherette $1.50 Modern Blacksmithing. eS Cloth $1.00 PAINTING BOOKS Scene Painting and Bulletin Art . + Cloth $3.00 A Show at Show Cards ............ Cloth $3.00 EE EE ee eee Cloth $3.00 CARPENTRY AND BUILDING Modern Carpentry........... 2 vols., Cloth $2.00 The Steel Square............. 2 vols., Cloth $2.00 Wooden Boat and Shipbuilding. hee ae Cloth $1.50 GENERAL INSTRUCTION AND REFERENCE BOOKS Elemen Chemistry, Self-Taught cioth $1.00 Complete Courses in ivil Service . . cloth $1.50 Practical Handbook for Millwrights Cloth $2.00 Just Out! FRENCH Withouta Teacher | SPANISH Withouta Teacher | GERMANWithouta Teacher By Professor Phillip @| Schuyler Allen, Uni- i versity of Chicago. An entirely new | home-study series of #4, modern foreign lang- } uages. Simplest, i easiest -to- master 4 language method ever ij devised. French, Spanish or German, Mail the Coupon NOW Order on our five day money back plan. FREDERICK J. DRAKE & CO., 1003 ee Ave., Chicago, IIl. Enclosed find ($..........+.+ , for which econo ound me prepaid “the books — It is apres * attached), days if ~~ aes funded in full. PERRO e HEHE EHH H HEHE EEE EH EH EERE HEHEHE OD Ignition’ by Electricity A novel way of lighting any combus- tible mixture is by means of electricity. Cover a six-inch square of wood with asbestos paper and drive into it two nails four inches apart. Between the nails taking a turn around each one insert a piece of No. 28 iron wire and on it place the mixture to be ignited. Connect the ends of the wire with 6 or 8 dry cells and close the circuit. The wire is heated to incandescence and the combustion follows. Nitrogen Iodide A nitrogen compound of extreme sensitiveness can be made from the reaction of iodine and strong ammonia water. In the bottom of a test 'GNITION POWDER tube place a few P ae cubic centime- ters of the TIN CUP strongest am- ; TRIPOD monia and add SUPPORT an equal volume SAND of concentrated BOX tincture of |[- la icdine. The tincture can be This mixture ignites made by shak- with a blinding display ing crystals of of light and streams ite P ; of molten iron flow iodine with @ into the tray of sand little alcohol. When the ammonia and iodine so- lution are mixed nitrogen iodide immediately separates in the form of a black powder. Nitrogen iodide is not at all ex- plosive when in solution, but is very explosive when dry, and only a very small quantity is necessary to demon- strate its great instability and ex- plosive nature. ‘Therefore shake up the contents of the test tube and pour successive small quantities on folded filter pa- pers. Allow these to dry, which will take at least an hour. When dry tickle one por- tion with a long feather and even this gentle friction will cause it to ex- plode with a sharp report. One of the papers held with The flame equals a flash tongs and end- of Ribtning in its bri. Genly depressed liancy. It isaccompan- OVer a Bunsen ied with feathery sparks flame will ex- plode with suffi- extinguish the PICTURE CORD WIRE GLASS PLATE OXYGEN \_||/| | IRON SPOON | PHOSPHORUS cient violence to flame. Blow upon another portion through a long glass tube and the sudden puff of air will cause the iodide to explode. Always make these explosions at long range and never leave any of the explosive lying about. 104 Popular Science M. onthly «, enMonths’Credit SEND NO MONEY According to * our simple easy ff payment plan, we will send you any Diamond for your examination, express prepaid. If satis- fied, pay one-fifth of the purchase orloe and keep it; balance divided into 10 equal monthly payments. SWEET Diamonds are superior in quality, distinctive in bez auty, perfect in cut—gorgeous bursts of radiz int sple ‘ndor, Can be exchanged at a yearly increased value of 744%. Ask us about this Profit-Sharing Exchange pies and for YOUR catalog, No. 479™M—II’S FREE, LW:SWEET& CO, 2-4 MAIDEN LANE,NEW YORK The Economy Safety zzz Modelled along the lines of the best known $1 safeties. Sent y complete with one blade for 35c. HERO BLADES— high quality steel, keen edges that shave and last. Also fit Gem, Star,Ever Ready. Write for sample package, 3 for 15c. Hero Safety Razor Co, 258 Logan Soret Brooklyn, THE AUTOMOBILE BUSINESS Be able to have the largest paying business in your town. There isa big op- portunity in this field for trained men. In six to eight weeks you will be ready for a Poel tion as Garageman, Automobile Expert or ensed Chauffeur and capable of earning from $90-$400 Per Month and More You learn by pasties on overalls and do- ing the actual work, under expert in- structors. By this method you can not fail. If you have yearned for a future where you can make big money—here it is. Write TO-DAY for information. BUFFALO AUTO SCHOOL 550 Pearl, Corner Tye r Street, Buffal 0, pps ar REDDING & CO. Publistiers and Manufacturers 200 Fifth Avenue Dept. S Send for a Complete Catalogue of MASONIC BOOKS Jewelry and Goods New Yorls ee SAAS TERE NIN Nar ae a TERNS SET SD 2 MNRAS AED OON ESE 9

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Copyright, 1919, p 7 WES by R. J. Reynolds | ; f “i Vi a in f, Tobacco Co, : RINGE AL the national joy smoke AY, you'll have a streak of smoke luck that'll put pep-in-your- }. smokemotor, all right, if you'll ring-in with a jimmy pipe or cigarette papers and nail some Prince Albert for packing! Just between ourselves, you never will wise-up to high-spot-smoke- a joy until you can call a pipe or a home made cigarette by its first name, then, to hit the peak-of-pleasure you land square on that two-fisted-man-tobacco, Prince Albert. Aj & Well, sir, you'll be so all-fired happy you'll want to get a photo- A . 3ERT graph of yourself breezing up the pike with your smoke throttle wide open! Quality makes Prince Albert so different, so appealing. And P. A. can’t bite or parch. Both are cut out by our exclusive patented process ! Right now while summer’s young you get out your old jimmy pipe or the ‘‘papers” and land on some P. A. for what ails your particular smoke appetite ! ae Buy Prince Albert everywhere tobacco is sold. Toppy red bags, : tidy red tins, handsome pound and half pound tin humidors—and 4 —that classy, practical pound crystal glass humidor with sponge CRIMP CuT 7 moistener top that keeps the tobacco in such perfect condition LONG BURNING PIPE AND ds CIGARETTE TOBACCO R. J. REYNOLDS TOBACCO CO., Winston-Salem, N. C. — ris 105

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iWrestling Book FREE co Learn to be an expert wrestler. Know scientific raN wrestling, self-defense, and zai jitan. Develop a e

splendid physique, and have perfect health. Join this popular school aad learn by mail. The famous world’s champions—the marvelous Frank Gotch and Farmer Burns offer you a wonderful opportunity. Wrestlinz is ie easily and quickly learned at home by mail. Men and boys write now for splendid free book. [RSSESERING| Eee choices ond is, abe age FOR HEALTH] RG w Send for free book today, stating your age. Farmer Burns Sclicol of Wrestling, B120 Ramge Bldg., Omaha, Nebo [I's the biggest money maker today. De- mand for repaired tires grows constantly. There never was a better time to start in this , business We teach you how to do expert work and show you best way to operate busi- ness. Repairmen make $30 to $50 a week; good repair, shops make $100 to $500 a week. WE TRAIN YOU BY MAIL Our course goes right to your home. It is Complete, Inexpensive and Practical. We guarantee to train you to be an expert tire repairman in three months so that you can 2 repair fabric tires, all makes of cord tires, big pneumatic truck tires and tubes. Course has endorsement of large tire factories. We show you how and where to get best equipment for doing work. Write today for free information and outline of our course. HOVEY EXTENSION SCHOOL OF TIRE REPAIRING 312 SECOND NATIONAL BUILDING, AKRON, QHIO

e fe 7 Telegraph Pictures i BY ELECTRICITY Complete sets of two machines of this marvelous equipment at ridiculously low Be prices. Instructive, mystifying and use- | ful. This picture of President Wilson was telegraphed by these machines. Will (ee transmit pictures, maps, drawings and He hand writing. Picture telegraphing is | the coming science. Write today J. LEISHMAN CO., Dept. H. Ogden, Utah ENORMOUS PROFITS {Bm START GROWING MUSHROOMS Learn the latest authoritative way to make still bigger profits than you ever thought possible or ever made growing mushrooms. Add $10 to $75 a week to —_ income. Anyone, men, women and children can do it in spare time in city or country. Grow in base- ments, cellars, sheds, boxes, etc. Start now. Demand bigger than supply. Send for big free book of expert_authority, ‘“The Truth About ~ ushrooms.’’ Write to BUREAU OF MUSHROOM INDUSTRY Dept. 558 5005 W. North Ave.

Chicago

‘TIONSECURE COPYRIGHT AND EMPLOY ORIGINAL METHODS FOR FACILITATING FREE PUBLICA- UNDER THIS SUCCESSFUL THE TRUTH CONCERNING EVERY BRANCH c OF THIS ESSENTIAL AND FACINATING PROFESS, ION THE GREAT WORK ACCOMPLISHED BY THE POF

ULAR SONG IN WINNINGTHE WAR IS ONLY AN INDEX TO THE Mudt f WIDER SCOPE AND GREATER OPPORTUNITIES AFFORDED BY PEACE. KNICKERBOCKER_STUDIOS, 88 Gate’ Buns.N.¥.Crr%

we SRST

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nate e Burns estling is mt, Men to handle ‘ful offer your age, nema aa | ay. De- nstantly. rt in this jlo expert ate busi- a week; ) a week, AIL ie. It is al. We FITS {ROOMS yay to make ver thought d for Dictree Truth About Chicago ' July, 1919 the Fiery] HE Big Swiss Yodler throws his voice across the valley—the echo registers that fact in four seconds. We marvel at the power behind such a voice. But let us not forget— The Fiery Little Columbia can carry the Big Yodler’s ordinary conversation over a thousand miles of telephone line, and deliver it instantly. THE DRY BATTERY ONSIDER, too, that besides tuning up telephones, Columbia Dry Batteries run toys, ring doorbells, and furnish the vital spark of life to thousands of autos, trucks, motorboats, tractors, and farm engines. The Fiery Little Columbia is never sick, for his constitution is tough; he is never tired, for he works only when you need him. Columbia bry patteries The Swiss Yodler throws his voice across the valley — ittle Columbia can throwa voice across a continent Always healthy, rested and vigorous, he meets every battery need faithfully and long. THE STORAGE BATTERY bee Columbia Storage Battery is built and sold to yield definite power for a definite time. Ina Columbia you buy definite service; you receive a clearly defined guarantee, a specific agreement that you will be entitled te thorough repairs or another battery without additional cost if the original battery fails within the guarantee period. The Columbia Battery Terminal Seal protects the battery, the purchaser, and us. The guarantee is a record of that fact. Stop at any Columbia Service Dealer’s or Columbia Service Station and learn how thousands of auto owners are avoiding the costly battery tinkering that used to be tolerated as part of a day’s work.

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CUNARD ANCHOR NEW YORK~ SOUTHAMPTON AQUITANIA MAURETANIA NEW YORK~ LIVERPOOL CARMANIA CARONIA ORDUNA ROYAL GEORGE SCHEDULES ON APPLICATION 21-24 STATE ST., NEW YORK OR BRANCHES AND AGENCIES ? ‘ That is why in many countries one in every six persons 4 rides a bicycle. That} is why inall = modern Armies, bicycles are used by the tens of thousan 3 5 A good bicycle is the work- jhe We \ a | i} AW Ree PHN Ly i man's street car, with the = cost of the rides saved. It is x ee finest eon ong out- money and get your bicycle direct from the maker. p sIm,Factory {to Rider Sales plan $25 i — you $10 Fs TIRE Parts ‘Repal \ F Tl ES monet orice. ead : we Build and Fly Model War Aeroplanes! Learn Aeronautics this sum- mer. Build a Model Aero- plane that will fiy like a real one. With IDEAL Scale Draw- ings and Building and Flying Instructions you can easily build exact, 3 ft. duplicates of well-known Aeroplanes. True-to- life: planes that fiy like real ones. Send for DRAWINGS and INSTRUCTIONS Right Away Curtiss Mili Tractor Wright Biclane riot Monoplane 25c Curtiss Flying Boat Nieuport Monoplane Each Cecil Peoli Racer. Taube Monopiene (7 tor $1.75) Catalogue of IDEAL Model Aeroplanes and Supplies, 5c. None Free. IDEAL AEROPLANE & SUPPLY COMPANY Cor. Hi and W Sts., New York City Be a Finger Print Expert Police departments, factories, andindustrics every- FINGER’ ba CO3 ew where are — ing thigs system of ep Ex- DENEMCM Erne ct home. Write for detalles sPOre Free Book—Write colin book on finger yrinte sent pbeclately free and prepaid. Also details — limited offer. Write at once, while this er UNIVERSITY OF APPLIED SCIENCE Desk 8120 1772 Wilson Avenue, CHICAGO Learn Piano! This Interesting Free Book shows how you can become a skilled plaper of — or organ in your own home, at ‘= ritten = Method is ‘nie — famous and heads of State Lag yy Successtul 26 years. chords at once and com piece in every key, within sons. Belentific met goer to understand Lan iloeteatad. For berin- ers, Write today ' for 64-page feo beak, ‘How to Study Music’’ — UL. QUINN CONSERVATORY, Studio ZG, Social Union Bldg, Boston, Mass. pe ‘combustion will follow, accompanied by the radiation of a multitude of brilliant sparks. In a darkened room the effect is much heightened. In the bowl of an iron spoon ignite a little red phosphorous and thrust into a bottle of oxygen. A white light of dazzling brilliancy results. Combustion of Sugar and Potassium Chlorate Carefully mix without friction equal quantities of finely pulverized potas- sium chlorate and cane sugar. Satu- rate a small piece of asbestos paper with concentrated sulphuric acid and, holding it with tongs, drop it on the mixture placed on asbestos paper. A very rapid combustion results ac- companied by an intensely blue flame. Nitric Acid The fundamental requisite for the manufacture of explosives is nitric acid. From the black gun-powder of a century ago to the nitrocellulose, Great care should be taken with this experi- ment, as the acid will burn anything it touches picric acid and T.N.T. of present day wartare, nitric acid has been the moving factor in high explosives. To prepare the acid arrange a ring stand, tubulated retort and condensing flask, as shownin the figure. Place in the retort about 15 grams of sodium nitrate and by means of a funnel pour over it 10 cubic centimeters of con- centrated sulphuric acid. Insert the stopper in the retort and heat the mix- ture very gently, using a small flame. Very soon small drops of the acid will be seen condensing in the neck of the retort and trickling down into the flask. If the contents of the flask begin to boil remove the flame and avoid, so far as possible, the production of brownfumes. Continue the process as long as any acid distils over. The liquid collected in the flask is very strong acid and care must be exercised in handling it. To show its oxidizing action pour a little of the acid in the bottom of the test tube and just above it place a loose plug of excelsior, cotton wool or boiler felt. Then, holding the test tube with a holder, heat the acid until 108 Popular Science M onthly “The Bi gest, Brig’ » Best Magazine — : ee pove in all the Worlds ? a: t Miss It Half a million boys read The American each month. It’s their own magazine, edited an ted just for boys. It has more stori Riestecd 7 ents whem an bet Dad to bring you home narer’ = his news dea aig Have him it over with He’s sure to like it, toe. He’ I subscribe for you. $2.00 a year—20c a copy on news-stands. THE SPRAGUE PUBLISHING CO. TRIAL Cat ont this ad and mail it to us, with your name and address (no money); and we will send you mr coma KARNAK RAZOR by return mail, postpaid. the razor for 30 days FREE; then if you like: sit, a y i §1.85. If you don'tlike it return it. SEND NO MONEY MORE COMPANY, Dept.397 St. “pe Me, Mathematics Made Easy TheA the Combination Triangle with a Brain—will ‘multiply, divide, figure percentage and proportion, solve all problem; i in trigonometry and geometry, draw symmetrical figures, plot arcs, etc. Superior to any slide rule. Simple to operate. Also includes A TRANSPARENT TRIANGLE, PROTRACTOR and THREE RULES. Used at Columbia University, West Point, U. S. Aeronautic Schools, Etc. Only 85c postpaid. Order today before you forget. Dept. U, L. J. LEISHMAN CO. Ogden, Utah RUNS ON KEROSENE ALCOHOL OR GAS ANYWHERE & A most remarkableinvention. No electricity, ¥ wires or springs. 1919 impreved patented Models. Runs 8 hours for a cent on kerosene. Quiet—Convenient. Brings genuine comfort and satisfaction. Ideal for the sick. A proved success. 5thseason. Every home and office needs the Wonder Fan. Three } Models. Three Sizes. BE WELL, KEEP COOL. Address Lake Breeze Motor, 58! W. Monroe S:., Chicago FS ]ASSPINS-RINGS DIRECT FROM bedhesl To You OUR NEW CATALOG. WITH 600 OF THE LATEST UP-TO-DATE DESIGNS FREE. C. K. GROUSE CO. . 12 Bruce Ave.. North Attleboro. Mass. \WRITE THE \VORDS FOR A SONG We write music and guarantee publisher's acceptance. Submit poems on patriotism, love or any subject. Don’tdelay. Send Words Today. CHESTER MUSIC COMPANY 920 S. Michigan Ave., Room 310, CHICAGO, ILL. siispicimaiiel S FIBRE LIMB is soothing to your stump,— . strong, cool, neat, light. Easy payments, Braces ZY for all Guaranteed 5 Years deform- Send for Catalog Today ities P. BUCHSTEIN CO., 113 6th St. S., MINNEAPOLIS, MINN. AGENTS $60 WEEKLY Robinson Folding Bath Tub. Big seller. Costs little, no plumbing, little water. Weight 15 pounds, folds into small roll. Full length baths, far better than tintubs. Guaranteed 10 years. $10 a day easily made. Write for free tub offer. ROBINSON CABINET MFG. CO., 4998 Factories Bldg., Toledo, 0. MAKE A MOTOR-CYCLE OUT OF YOUR BICYCLE with A STEFFEY MOTOR Easy to attach. Fits any wheel. More STEFFEY’S in use than all eA} others. Send stamp for circular ” and low factory prices. Dept. S, 5025 Brown St., Philadelphia, Pa. Agents wanted. STEFFEY MFG, CO.

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er’s ism, NR RA ORO MSEERS NOE AIELLO a RSENS July, 1919 18 cents a package Camels are sold everywhere in scientific- ally sealed packages of 20 cigarettes or « ten packages (200 cigarettes) in a glassine- paper-covered carton. We strongly rec- ommend this carton for the home or office supply or when you travel. R. J. REYNOLDS TOBACCO CO. Winston-Salem, N. C, are so refreshing, so unusual in flavor and fragrance; so satisfying in the mellow-mildness of their “body”! Be- fore you have smoked many you realize Camels supply everything you ever asked for in a cigarette smoke! Camels delightful newness comes to you through the expert blend of choice Turkish and choice Domestic tobaccos. This blend makes it possible for you to smoke Camels liberally without tiring your taste. Besides, the blend eliminates any un- pleasant cigaretty aftertaste or unpleasant cigaretty odor! Your tryout of Camels wil]l prove their distinctive qualities. And, prove that you will prefer this expert Camel blend to either kind of tobacco smoked straight. Camels superiority stands out best in comparison. Put Camels in a taste-test with any cigarette in the world at any price!

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Experimenters! Are you listening to Rome, Lyons, Eiffel Tower, Darien and Nauen Discussing Mat- ters of World Interest ? Your own air condenser with 3 of our new “Honeycomb” wound inductances makes this easily possible at a cost so low _it will surprise you.

Honeycomb Coils For Wave Lengths 150-25000 Meters Vernier Condensers From $10 to $18 Our new Vernier Condenser when used in connection with these devices complete a long wave receiving: set which cannot be surpassed for double the: money. Made in Various Sizes. Particulars and prices on application. DE FOREST RADIO TEL. & TEL. CO. 1415 Sedgw:ck Avenue, New York City.

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=- tiens and Trade Marks, Their Protection. and Exploitation” and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, too. 4 postal will do— it is free.

PATENTS ADVERTISED For SALE FREE We help our clients, without charge, to get the dollars out of their ideas—having facilities none others possess. Advice free. In INVENTION And pooesece? “TU MANUFACTURING aa SUPPLEMENT. Published for the man with an idea. INDUSTRIES, INC, Send for free sample 201 Patent Dept., copy. One year’s sub-

WASHINGTON, D.C, m scription 50c.

Send for Halcun Radio Catalogue Full Line of Amateur Requirements HALCUN RADIO CO. San Francisco, Cal. Formerly Haller Cunningham Elec. Co.

it boils. As the hot vapor comes in contact with the combustible plug the latter will spontaneously ignite. Combustible Gas Rings A very striking and pretty demon- stration of spontaneous combustion may be carried out as follows: Ar- range’ apparatus as shown in the diagram. In the flask place about COCK

As the bubbles rise they form a wreath of smoke of peculiar effect 300 cubic centimeters of a strong: solution of sodium hydroxide and introduce two or three small pieces of yellow phosphorus. (Do not hold the phosphorus with the fingers. Handle it with pincers.) Then pass ordinary illuminating gas through the flask to expel the air. To do this connect the bent glass tube dipping beneath the solution with a gas cock by means of rubber tubing. Now gradu- ally heat the flask and con- tents with a Bunsen flame. When near the boiling point a gaseous com- pound of hy- drogen and phos- phorus, called phosphine, be- gins to form, and as each bubble of the gas escapes from the water into the air it spontaneously ignites. In so doing each bubble forms a wreath of smoke which expands as it rises, giving a very striking effect. The steam that issues from the tube is luminous Phosphorescent Vapor In a small flask, fitted with a one- holed cork stopper and a short piece of straight glass tubing, place 20 cubic centimeters of water and a phosphorus match-head or small piece of phos- phorus. Heat to boiling, and the steam will be luminous in a darkened room. 110 og

Popular Science Monthly Send You a Lachnite "T senda Just send nite poe OF pay eg @ month until $18.75 : bez sold gold owe eae Ep rhieh ot the | Gadies’ or men’s). Be sure to

EASIEST SHORTHAND Learn in 5 evenings home st then acquire epeed w ith K. 1. snore: sage +a as $| afterbrief, pleasantpractice. Favor- for personal use; 4 notes at lectures, Bie nef in confidential diary. Big bet ae any 0} pr r Used inA: ieiey = commercial schools: by ‘public and private ate ours, phers, teachers. Slight ¢ . K.1.Shortha end--for aay people. , including YOU, Pre og: Cpesene; Cuarantee snd rochure with Testimonials tree. p. ostpaid. Ad KINGINSTITUTE, EH-188, ‘Station F, NEW YORK City LEARN TELEGRAPHY athomein shorten, possitie Gm time, Morse or Wireless APH AUTO. M Cc TRANSM MITTER, connected th Sounder or Buzzer, sends you messages beg ee - just as ‘ 3 ax opera’ e t e i U's: Govt. 6 styles. “Catalog tree, <7 (MNIGRAPH MFG. CO. $9-H Cortlandt St., New York

Bact Vulcan” Ink Pencils The ONLY perfect, non-leakable ink pencils at moderate prices. Your name in gold inlay—$.35. Order $ today. ] 25 ry FREE—Liberal supply of ink with retail orders. Agents wanted. Big profits J. F. ULLRICH & CO., 27 Thames St:, New York

Two Sizes— 44% and 5% inches. Extra Size— 8 inches(black only) $1.50.

Be a watchmaker—you can learn this profitable epai 77 by correspondence in a few weeks in your own home by the DeSelms Chart System. After youcomplete # the course you will know a watch from AtoZ. You will know just what the matter is and how to repair one. When you graduate you will be @ practical watchmaker and repairer and competent to any position. Positions forour graduates, aie Ee THE DeSELMS WATCH SCHOOL 6 87 Perry St., ATTICA, IND. -$9010°250.aMonth Daya bie) (eli ceslenty Write today for this big, new Free Book on SIGNAL ENGINEERING Railroads need men for this important work. Big sitions open throughout United States. Big ‘ree Book tells all about it—tells how vou can get the weer training you need. Write for it—Today—Now Dept. of Signaling, Room B120, 1810 Wilson Avenue, Chicago

Bs IGNAL ~ ENGINEERING

Comics, cartoons, com- mercial, “wo and Magazine illustrating. Pastel crayon portraits and Fashions. Earn $25 to $200 a week. Ly our simple method your talent is quickly de- veloped without interfering with present work. By Mail or Local Classes. The largest practical art School in the world. Write for full particulars and list of successful pupils, illustrated prospectus, etc. Endorsed by news- papers and magazines. ASSOCIATED ART STUDIOS, SSD, Flatiron Building, New York, N.Y. Don’t Wear a Truss Brooks’ Appliance, the modern scientific invention, the wonderful new discovery that relieves rupture, will be sent on trial. No obnoxious springs or pads.

MR. C. E. BROKS Brooks’ Rupture Appliance Has automatic Air Cushions. Binds and draws the broken parts together as you would a broken limb. No salves. No lies. Durable. cheap. ‘Sent a trial to prove it. Protected bv U. S. patents. Catalog and measure blanks mailed free. Send name and address today. BROOKS APPLIANCE CO., 255B State St., Marshall, Mich.

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July, 1919 Casting on Aluminum Knife Handles HOSE bright and shiny aluminum knife handles usually come from the factory where the knives are made, put do you know that with very little work and a few home-made tools they can be cast on at home in case of accident? Butcher shops, res- taurants and repair shops all require repairs, and a profitable repairing business could be built up by an itinerant workman, for he furnishes nothing but the aluminum. This may be secured quite cheaply at junk yards or garages, in the shape of broken and discarded crankcases, etc., and the scrap metal is easily broken to bits ‘ “UPPER HALF FLASK BARS —SS——SS - = ———— SS " _———> SLOT FOR. BOTTOM BOARD KNIFE BLADE SPLIT HERE PATTERN SHANK OPENING Here’s a new industry for the small-town mechanic who wants to make a good living for melting in a common babbitt ladle. The mechanic could even pur- chase new metal and still make money on the work. First, carefully remove the lid and bottom of two cigar boxes. Next, cut the lids into strips and construct a set of guides at each side of the cigar boxes as shown. The boxes now fit together, one on top of the other with the guides to prevent shifting. Strips are now made into cross bars for the upper half of the molding box. The bottom of one box is used for bottom boards for the mold. Next in importance is the handle pattern. This may be made according to the taste of the mechanic, either round, square, or odd shaped. The handle pattern shown in the drawing is to be made of soft pine, split as shown into two parts. These parts should be doweled together near the edge. The center of each half should be hollowed out to fit the shank of a knife. Now obtain a couple of quarts of moist earth from the garden and sift it to remove all foreign matter, pebbles, sticks, etc. Before using make it moist enough to stick together when squeezed into a ball with the hand. It should not be wet because if it is the molten aluminum will not stay in the mold when it is poured. A small quantity of dry river sand is needed to separate the halves of the mold; this is called parting sand. A short piece of stick Yin. round, called a gate, completes the equipment for molding. “ Here’s Where We Got tg “Look, Nell—this coupon! Remember the night you urged me to send it in to Scranton? Then how happy we were when | came home with the news of my first promotion? We owe it all, Nell, my place as Manager, our home, our comforts—to this coupon.” Thousands upon thousands of men now know the joy of happy, prosperous homes because they let the International Correspondence Schools prepare them in their spare time for bigger work. You will find them in city, town and country — in office, factory, shop, store, mine and mill, on farms and on railroads. There are clerks who became Advertising Managers, Salesmen and Executives; carpen- ters who became Architects and Contractors; mechanics who became Engineers and Electrical Experts; men and boys who rose from nothing at all to splendid responsible positions. There are such men as Jesse G. Vin- cent, who advanced from toolmaker’s apprentice to Vice President of Engineer- ing of the Packard Motor Car Company. Such men as H. E. Gardner, who won through I. C.§. spare time study the training that equipped him to build the great Equitable Building. These are but examples. They have proved what men with ambition can do. More than a million men and women in the last 28 years have advanced them- selves in position and salary through I.C.S. help. Over 100,000 are study- ing right now. You can join them and get in line for promotion. The first step to success in the I. C.S. way is to choose your career from this list and mark and mail this coupon here and now. oH Fo a TEAR OUT HER em eae cee cee aoe INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7644, SCRANT ‘A. N, Explain, without obligating me, how I can for the position, or in the subject, ‘before which I mark X. ELEOTR ICAL ENGINEER SALESMANSHIP Electric Lighting an@d Rys. ADVERTISING Electric Wiring Window Trimmer Telegraph Engineer Show Card Writer Telephone Work Sign Painter MEOHANICAL ENGINEER Railroad Trainman Mechanical Draftsman ILLUSTRATING Machine Shop Practice Gectoontes., Toolmaker BOOKKEEPER Gas Engine Operating Stenographer and Typist CIVIL ENGINEER Surveying and Mapping MINE FOREMAN or EN@’R Cert. Pub. Accountant TRAFFIC MANAGER Railway Accountant STATIONARY ENGINEER Commercial Law arine Engineer GOOD ENGLISH Ship Draftsman Teacher ARCHITECT 0 Subject Contractor and Builder Archite ctural Draftsman crete Builder lerk Structural Engineer AUTOMOBILE OPERATING PLUMBING AND HEATING Auto Repairing Sheet Metal Worker Navigation Spanish Textile Overseer or Supt. AGRIOULTURE French OHEMIST Poultry Raising Italian Name. Present Occupati Street and No. . | City. State. Canadians may send this —_ to International Correspondence Schools, Montreal. fanada BOYS! B ELECTRICITY Let the I. C.S. help you. Choose the work you like best in the coupon, then mark and mail it to- day. This doesn’t obligate you in the least, and it will bring you information that will start you ona successful career. This is your chance. Don’t let it P by, Mark and mail this coupon now. 111 ig M y! ig Money! There is a wonderful opportunity right now for boys who like electricity. Boys who are ambitious and will train themselves in spare time can step into positions just assoon as they are ready. Good salaries are offered to start with splendid chances for rapid promotion. For 28 years the International Correspondence Schools have been training boys for success in electricity and over 200 other subjects. 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 appeals to you. Thousands of boys, through I. C. S. training, have stepped into fine jobs, but never were opportunities so great ds now. -——— = TEAR OUTHERER Oe —— — INTERNATIONAL CORRESPONDENCE SCHOOLS ox 7645, Scranton, Pa. Explainfully about your Course in the subject marked X: ELEOTRIOAL ENGIN’R §()Telephone Wor! ADVERT’S'G ELECTRICIAN |Mechanical Engin’g #_J)BOOKK’I"@ ELEOTRIO WIRING Mechanical Draft’g Stenograp’y ELEOTRIO LIGHTING Civil Engineering Civil Service ELEOTRIO RY. WORK Stationary Engin’¢ AUTO iOR'S ELEOTRICAL DRAFTS’N §_)Mining Engineer’g Ship Dratt'’g ELEO. MAOH. DESIGN’R AROCHITEUOTURE OHEMISTRY TELEGRAPH EXPERT Architect’! Drafting _)Farming Name Address.

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everywhere repair and give Big money for M. S. A. trained men, businesses await our graduates, unlimited, Earn $100 to $400 Monthly too h lere you get the benefit of finest co-operation of biggest factories. poate glad Ip help our students in every way possible. , Almost daily we have calls for to Trained men needed to test, expert advice on care and handling of automobiles, trucks and tractors. S. — Detroit Good jobs or independent Opportunities ool open all year. Enter classes any time. No need to waste or lose a moment. ™ MONEY BACK GUARANTEE We gnertniee to qualify you for a position as chauffe ster, demonstrator, auto electri man, automobile dealer, or an paying from $100 to $400 monthly, or refund your money. ] “a Big Factories Endorse Our School usual assistance. man—one who knows and is able to teach Our course will teach you how in a few short weeks. Most complete, comprehensive and up-to-date Course known. Wholly practical. No job for our graduates. Every phase’of work covered. . Actual experience given on dozens of different cars. Entire equipment best obtainable. Instruction me oy complete Tractor Course. Brazing, Welding and Tire Repairing taught Learn in Detroit—Start Any Time—Our Graduates in Demand They know the thoroughness ei our Course ur, cian. garage They know what we do—how we teach and the type ° of graduates we turn out—and give our students un- Every instructor an experienced others. Hine MoToR CAR Commany Beupeur or DETROIT Kove Care ARTEMAR wan. oe wotns eae Dernort.u.8.a. Tells all about ‘‘The Old Reliable School” located in “‘the Heart of the Auto Indus- ‘ . try.” Or, better still; jump on the train and come to Detroit as .Hundreds do. Your fare refunded if everything not as represented. - MICHIGAN STATE AUTO SCHOOL Replying to a necent letter addressed to Mr. Ward making Sart ag the reputation of the chigan tate Auto 1, will say that as far as we know al troit Automobile factu di the work they are doing. 7 is if ged very efficiently and they have bee furaing cut some —e = forthe automobile _ A. G. ZELLER, President ee d cannot see any reason why you shoul 587 Auto Building, Woodward Ave., Get Free Catalog _ | DUOUSTRY Detroit, Mich., U.S.A MRRP UET THEA TACHA C ERROR TERE RT TEL Pacer eee e eset bess PATEN TS Trade Marks | Send sketch or model for actual search and report. Write for Book- let of instructions on patent practice and procedure. Prompt personal service.... Geo.P Kimmel Patent Lawyer IE 39-¥ Loan and Trost Building, Washington, D.C. Opeeietee euetauretereere Before applying for a patent you should send us a sketch or model of your invention, with a description of it, and receive our “Evidence of Con- ception” form—our Opinion as to the Patentable Nature of your In- vention, and our advice regarding the tempareetepentoa best way of obtaining patent protection. Our practical experience covers a period of twenty years. Our Handbook on Patents : HOW toOBTAINaPATENT : SENT FREE =\ is a storehouse of valuable information and E\ advice toinventors. All communications = > strictly confidential. Writeus TODAY. _, Mf Al Ah Ml ls lL A Ml Sl el heaoene 4621 Talbert Bldg., WASHINGTON, D. C. eUPU RPE SSC OSES SE SEBE CEU Se eSG5e £25 ERAGE) . o = - ~ = - ~ ~ - - - - - - - “ os = = - * « - ~ - -~ = - ~ ~ - = - - — - _ - - ~- ~ DEAFNESS IS. MISERY I know becanse f*was Deaf and had Head Noises for over 30 years. My invisible Antiseptic Ear Drums restored my 4 ompees Head Noises, and will do it for you. ey are Tiny Megaphones. Cannot be seen when worn. Effective when Deafness is caused by Catarrh or by Perforated, Partially or Wholly Destroyed Natural Drums. — to put in, easy to take out. Are “‘Unseen Gomforts.’’ In- expensive. Write for Booklet and my sworn statement of how I recovered my hearing. A. O, LEONARD Suite 301, 70 Sth Avenue - ” New York City o alth? Take Turkish Bath at Home . —ONLY 2 CENTS Physicians are abandoning d: f ~ this new treatment. If your mind or body is tired, or agg 3 have rheuma- tism, blood, stomach, liver, kidney and skin troubles, open your pores, and feel the id change in your condition, at cost of 2ca bath. ‘obinson Cabinet is the only scientifically con- structed bath cabinet ever made for the home. Great $2 Book Sent FREE Beauty.’’ ite lay. Agents wanted. ROBINSON MFG. Co. 988 N. Twelfth St., TOLEDO, OHIO IF YOU HAVE AN INVENTION AND DESIRE TO LEARN HOW TO P SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. Tells our Terms, Methods, etc. Send model or sketch and description of your invention and we will give our opinion as to its = patentable nature. RANDOLPH & CO. 130 F St, N. W., Washington, D. C. eee eee ee ey —_— oe ee ee oe oe, mn E (| | Pewee ese esesesesee Popular Science Monthly The melting apparatus consists of a common blow torch and a small’ babbitt ladle, or the metal may be melted in any stove or furnace at home. When the equipment is ready the first step is to remove the old MOLDING EARTH tedelchcdaeadddedddddddddddeddded dada HALF PATTERN BOTTOM BOARD wana GATE YY YY BARS Z UW , SSA EE LESS SESE EEEESE LESSEE PUSS NESE PATTERN CAVITY MOLDING EARTH A sectional view of the mold, showing how the aluminum is poured into it handle from the knife. Then heat the shank red hot to burn out any moisture or grease. Sometimes it igs well to have the shank of the knife hot when casting the metal. The molding is done thus: place the nowel half of the pattern on a bottom board and place the nowel or lower half of the molding flask around it. The slotted end of the pattern should be towards the slot end of the flask. Fill the half box with the moist earth; press it firmly in and pat it down, but not too hard because the metal boils in hard molds, spoiling the casting. . After the half flask is filled, level it down and place another bottom board on it. Then turn the whole thing over and remove the first bottom board. Blow away any loose dirt and sprinkle a thin layer of dry sand over the surface. Place the shank of the knife handle in the hollow of the pattern. On top of it fit the other half of the pattern. Now the gate stick is put in place as shown in sectional drawing of mold, and the top half of the mold is pressed full of the molding earth. It is pressed only firmly enough to hold it in place between the cross bars. The gate stick is now with- drawn and the hole made funnel- shaped at the top to receive the melted aluminum. Next the top half of the mold is raised and lifted off, the patterns are drawn and the knife blade heated and replaced. The half molds are put together again and made ready to receive the. melted metal; the two halves must be clamped together, or weighted down, else the pressure of the molten metal will force the mold apart and spoil the job. The cross sectional drawing shows the way the mold should look ready to pour. An ordinary tool box is employed to transfer the equipment from one house to another if the work is done this way.— DAVID BAXTER.

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DE. INK leat any t is nife the tom wer 1 it. ould ask, th; » but Doils ting. el it oard hing ‘tom and over the the half ck is onal lf of ding ough cross vith- nnel- the top ifted | the The . and elted mped e the force The — the ly to loyed 1 one done rn nae ere July, 1919 Take in Your Lawn When It Rains E don’t mean exactly that, but some very curious mats have been produced by growing real grass on pieces of burlap. The plan is an interesting one, for whether the mats are used in a green or dried state, they are highly attractive. The first step is to get a piece of purlap of a suitable size. This should be well moistened and placed upon a flat surface. Sow the seed somewhat The grass mat is a novelty and adds to the appearance of the porch thickly and give it-water when needed. The seed soon germinates and where there are signs of thin places—like the bald spot on Dad’s head—more seed must be sown. ; If the mat is resting upon soil it must be moved about from time to time, as this will prevent the roots of the grass from going through the burlap into the soil. As soon as the grass is three or four inches in length the mat is ready for use. Contrary to what one would expect the blades of grass are not easily pulled away, so closely do they cling to the fibres of the burlap. A charming effect is secured by using the mats in a green state. If the burlap is kept slightly moist the grass will remain fresh and green for a long time. The mat may be placed upon a piece of linoleum to prevent the slight dampness causing any damage. To dry the mat off, it is only neces- sary to hang it up and give it no water. The grass turns a pretty shade of dull green and serviceable mats that will wear for a long time may be made with a little more care in the prepara- tion of the foundation before the seed is sown. Mats of this sort may be used in a variety of ways.—S. LEONARD BASTIN. How Long Is the Life of a File? ILES are short-lived instruments. One investigator -estimates that their useful working days are two, of ten hours each, and in that time they have made an average of 25,000 strokes. Worn files should be discarded promptly in the interest of economy, as it is estimated that, counting the work- man’s time and overhead charges, a new file can turn out for $4.60 work that would cost $10.60 with a worn file. _\ . , # PATENT TRADE-MARKS - AND ote) A Ali ae Before disclosing an invention, the inventor should write for our blank form “EVIDENCE OF . CONCEPTION.” This should be signed and witnessed and if returned to us together with model or sketch and description of the invention, we will give our opinion as to its patentable nature. Our Iilustrated Guide Book, HOW TO OBTAIN A PATENT, sent Free on request. Contains full instructions regarding Patents, Trade-Marks, Foreign Patents, Our Methods, Terms, and 100 Mechanical Movements illustrated and described, Articles on Patent Practice and Procedure, and Law Points for Inventors. Highest References | Prompt Service Reasonable Terms VICTOR J. EVANS & CO., Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices 1001 Woolworth Bldg. 13S S. Broad Street 514 Empire Bldg. Main Offices: 760 Sth Street, N. W., WASHINGTON, D. C. GENTLEMEN: Please send me FREE OF CHARGE your Book as described above. COHORT HEHE EE EEE EHH HEHE HEED Ceres mann ees ou eS PATENTS LACEY & LACEY > Sa NI Attcrneys-at-Law — Patent Practice Exclusively To the Man With an Idea i B | Solicitors of I off aici ‘ . offer a comprehensive, experi- U. S. and Foreign Patents enced, efficient service for his = * " prompt, legal protection and the Trade-Marks, Copyrights development of his proposition. 645 F Street, N.W., Washington, D.C. 1 a Send sketch, or model and descrip- tion, for advice as to cost, search Write Us for Our Free Inventors’ Book PATENT-SENSE through prior United States pat- ents, etc. Preliminary advice glad- ESTABLISHED 1869, ly furnished without charge. My experience and familiarity with various /@ arts, frequently enable me to accurately 4 advise clients as to probable patentability before they go to any expense. + 4 Booklet of valuable information and form t.4 for properly disclosing your idea, free on #4) request. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C. 2276-D Woolworth Building, New York City PATENTS AND N TRADE MARKS [ANCASTER © & ALLWINE 274 OURAY BLDG, “= WASHINGTON, D.C. DO NOT LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to any one send for blank form ‘Evidence of Conception”’ to be signed and witnessed. Establish your rights before filing application for patent. As registered patent attorneys we represent hundreds of inventors all over the U. S. and Canada in the advancement of their inventions. Terms reasonable. The form “Evidence of Conception,”’ sample, instructions relating to obtaining of patentand fee schedule sent upon request. Ask for them,—a postcard will do. ATENTS PROCURED and TRADE-MARKS REGISTERED Eighteen Years’ Experience. Instructions and Terms on request. ROBB & ROBB, Attorneys at Law Specializing in Patent and Trade-mark Practice exclusively 840 Southern Bidg., Washington, D. C. Arithmetic of Electricity—A practical treatise on electrical calculations of all kinds reduced to a series of rules. $1.00 Postpaid. Popular Science Monthly, 225 West 39th St., New York. PATENTS Write for free booklet Terms Reasonable Highest References Best Results Send model or drawing for preliminary examination and report as to patentability 1336 Schofield Bldg., Cleveland, Ohio. ALL BUSINESS GIVEN PROMPT AND PROPER ATTENTION WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D.C. 113

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Popular Science M. onthly x ia ne Radio For additional articles on radio and its developments the reader may be referred to pages 32, 35, and 83 of this issue Radio and the NC Planes 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 communications are strictly confi- dential. Our vast practice, extending over a period of seventy years, enables us in many cases to advise in regard to the client. is sent free on request. Patents, Patents, etc. If you are a reader of the SCIENTIFIC act that it has a special appeal to the inventor. Each issue contains a description of a large number of recently pat- ented inventions. Pending pat- ~_ legislation as well as the ost recent rulings of the Patent Office and the courts are considered in its columns. SOLICITORS OF PATENTS patentability without any expense to Our Hand-Book on Patents This explains our methods, terms, etc., in regard to Trade Marks, Foreign MUNN & CO. 683 Woolworth Building, New York COMFORTABLE—COMPACT For convenience,strength and com- fort—on camping trips, for porches or extra furniture for the home —you will find nothing better than GOLD MEDAL FOLDING FURNITURE Made of specially selected hard- woods, three finishes, covered with highest grade heavy duck or carpet as you prefer, all joints reinforced with steel plates riveted on. Write for catalog showing cots, chairs, tents, etc. Gold Medal Camp Furniture Mfg. Co. Dept.7 Racine, Wis = \, hd Print Your 07 Own LAY. Pa: itself in short time. Will cards, circulars, labels, tags, menus book. Press $6. La auger Job a Bias ie" OUTS EXPENSES INHALF. SMALL OUT for last ? foryears. Easy to use, printed BIG PROFIT. cards, paper. pri rales sent. Print for others, Write facto TODAY for press catal TYPE, TY 08, THE PRESS CO., 0-33, Meriden, Conn F surpassing interest the last few weeks has been the flight of the American naval airplanes across the Atlantic. Little has been given out as to the airplanes’ radio-telegraphic and -telephonic equipment. And yet, these instruments were as important to suc- cess as the airplanes’ other features— TENSION TERMINAL 1000 CYCLES 3 Showing the 14-kilowatt set assembled, dem- 624 F Street, Washington, D. C. onstrating its compactness and accessibility. INKER, Tower Building, - Chicago, Ill. At the right are details. The winker lights howe ‘twink’? when one operator is sending, signal- __| FIELD ing the helper, and vice versa. This prevents SWI them from any interference with each other SFKEYS often their sole eyes and ears. POPULAR ScIENCE MONTHLY is fortunate this month in being able to present details on this exceptional radio equipment. The NC boats have two complete radio sets. One is of %-kilowatt capacity, with a normal sending radius of 300 to 400 miles, though under especially favorable conditions this may go to 1,500 miles. The generator on this set is wind-driven. The other radio unit is operated by a compact 12-volt storage battery. With this set both radio-telegraphic and -telephdnic communication may be carried on. The sets performed remarkably at all times during the flights. At one time the. Assistant Secretary of the Navy in Washington filed a message inquiring the position of one of the airplanes. Within three minutes a re- ply was received, uncommonly quick time. Balboa, Canal Zone, and San Diego heard also. The battery unit is installed to permit communication when the air- AMERICAN RANSTORMER FAN - GENERATOR SPARK CONDENSER man Weight of set complete, u are probably aware of the SHAFT , 45 1lbs.—unusual lightness 150-10000 VOLT TRANSFORMER plane is riding on the water and the wind therefore insufficient to operate the generator on the other winit. This set’s aerial is up on the skid fins of the upper wings—well out of the water at all times. The %-kilowatt set’s consists of 250 feet of wire, which trails out below and behind when the airplane is in the air, but which is reeled in upon descent. The especially prominent feature about the 4-kilowatt set is its com- pactness and light weight—45 lbs. Experts acquainted with the set say that this reflects unusual credit on American technique. An ordinary %- kilowatt set used on shipboard may weigh 600 lbs. Generator, spark- Radio Experimenters! ITH this issue the POPULAR communication. Therefore, let’s hear from you! contributions. publication of its radio articles, now that the government permits the operation of receiving sets and promises soon to remove all restrictions. Since the United States entered the war an industry has grown up employing several hundred thousand men in manufacturing and distributing alone, not to mention the thousands of commercial and amateur radio operators scattered over the world. Here is an audience waiting to learn of the new things in radio It is the POPULAR SCIENCE MONTHLY’S purpose to give them the vital, important radio news. If you’ve evolved some new radio idea you think is interesting, if you’ve witnessed unique processes growing up in factories producing radio apparatus, or had to do with uncommon experiments and developments, or know of noteworthy work or exploits of operators using apparatus in the field—let’s hear from you! The POPULAR SCIENCE MONTHLY pays liberally for all acceptable Let’s Hear from You SCIENCE MONTHLY resumes the 114 ARE ee esas Sof Slanted PGR aR IE AF

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the Te- ick san to 1ir- ete, 1€ss the ate nit. fins the att ich the is ure ym- lbs. July, 1919 el ele, 0 UN i\; $095 writs ar Tax Ghe Cleveland ACK of excessive weight and ease with which iL the CLEVELAND is handled make it the ideal motorcycle for tradesmen and tourists. Low center of gravity means easy control and safe riding. Low riding position means readiness for any traffic emergency. The rider is never compelled to remove his hands from the bars. The changing of gears requires only a pressure of the right foot and the brake pedal is operated by the left foot. The only lightweight motorcycle —_—eeee by the United States War Department Two Stroke Valveless Motor Unit Power Plant Worm Drive Transmission Standard for Four Years Write for catalog and agency. (One dealer sold six carloads ast summer.) The Cleveland “9p Motorcycle Mfg. Co. \ Cleveland, U.S. A. c Adventures of the ceAuto -Whee\ Coaster Club “The Free Caps Arrive’”’ “We formed the Club last week. The caps came today and they’re real class — racy looking, like the Auto- Wheel. Jim’s is a special one, because he’s captain. “Any kid who has an Auto-Wheel Coaster or an Auto-Wheel Convertible Roadster can join, and get one of these caps. ‘“‘We’ve planned several ‘stunts’ for this summer — things we can do with our Auto-Wheels.’’ BOYS—The Auto-Wheel is the wagon. Two styles: Coaster and Convertible Roadster as shown above. Color Catalog and Feit Pennant free for the names of coaster wagon dealers, telling which one handles the Auto-Wheel. The Buffalo Sled Company 157 Schenck St. N. TONAWANDA, N.Y. (In Canada: Preston, Ont.) “DONT SHOUT’? “| hear you. I can hear now as well as anybody. ‘How?’ With THE. MORLEY PHONE. I’ve a pair in my ears now, but they are invisible. I i not know I had them in, my only that I hear all right. ~ “The Morley Phone for the is to the ears what glasses are to the eyes. Invisible, comfortable, weight- less and harml ess. Any- one can adjust it.” Over one hundred thousand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, Perry Bide. Phila, ae MONEY SAVINGS FOR YOU Usedand rebuilt motorcycles, single and twins, ore $10 Mie bicycles, $5.00; ; tan ms, machines guaran’ in good working order. New bi- «ycles and motorcycles at Fac- tory prices. You save dealers’ profits. Motorcycle and auto- mobile tires —* $3. 7 , Gomm plete Gycleco. ;Rochester.N.Y. Y. gap, transformer, condensers, and so forth, are all contained within a single stream-lined body. As is apparent from the illustration, the spark-gap has two rotors, one with twelve pro- jections and the other with eight. Both revolve at the same rate, but one de- livers 1,000 sparks a second and the Indicating the position of the 14-kilowatt set on the NC airplanes other 666, thus producing two distinct tones, either of which the operator may use, and which permit greater selec- tivity, or the choosing of the tone best able to carry through radio traffic in the region at the moment. The diaphragm on the telephone transmitter is open front and rear, so that engine noises neutralize them- selves. But the operator’s voice reaches but one side, so its impulses carry through. Radio operator, pilot, navigating officer, engine man, helpers —in fact, the whole crew of five or six men—are all in intercommunica- tion at all times by telephone, and naturally with the other planes if they happen to be within the in- strument’s working radius, around 20 miles. The telegraph part of the set will reach about 30 miles, though "VARIOMETER, ASSEMBLED. Details of the variometer ac- companying the 14-kilowatt set of course these distances become greater or less with varying atmos- pheric and ether conditions as with any radio apparatus. Within the tail of the plane, coils forming the radio compass are mount- ed. These are revolved at will by the operator through the aid of suita- ble connecting mechanism, and are most important in helping the plane locate itself with respect to ship and land stations. The “NC” in the airplanes’ names comes from -“N,” Navy, and “C,” Curtiss, indicating the type. The number that accompanies the “NC” denotes merely numerical order. 115 Get Bigger Pay trout fog ELECTRICITY You_will find in HAWKINS GUIDES just what you need to know about electricity. In simpls everyday language— complete, concise, to the point. In questions and answers. A complete standard course in Electri Lg = for your set today to Experiments— Dynamos— Electric aay tA at ; ‘ ‘e Windings*~Installing of Dyna- mos—Electrical Instrument Tes ‘Practical Manage- ment of Dynamos and Motors-~Distribution Systems— Wi Wiring Diagrams—Sign Flashers—Storage Bat- teries—Principles of Alternating Currents ard Alternators Alternating Current Motors — Transformers — Con- verters—Rectifiers—Alternating Current cuit on rennere —-seeraring Instrumente—Switch Boards ec Gkations Installing Telephone —Telegraph— Wircloss Bolls--Lighting—Railways. Also many mod- ern Practical Applications of Electricity and Ready’ Refer- ence Index of the 10 numbers. THEO. AUDEL & CO., 72 Fifth Ave., N. ¥. leas submit for ex soma mets Electrical Price $1 cook), at a prepaid. the 10 sath within a 1d to to farther mail you $1 each , NOISELESS “TARGET PRACTICE Fit your .22 with a Maxim Silencer and get no end of fun this summer practicing in your backyard and on your vacation. MAXIM SsLENCER. EE It eliminates recoil and all noise FR K of the report, and_steadies your BOO aim. Direct from Dealer or Fac- SEND tory, $5.00. Write for Free Book iT of Stories. FOR MAXIM SILENCER Co. 91 Homestead Ave., Hartford, Conn. ‘Write Secret Letters With Invisibie Ink Pour seemingly plain water into three glasses and have it oan — in one, white in ano and blue. in the third! Make ve agic writing paper, and blue ink or ink qowder. rite with plata water and ave the writing turn biue. You can surprise and puzzle your friends with these and more m sterious and amusing Chemical tricks, if you have ‘“CHE MCRA RAFT’’ unior—the boys’ miniature chemical outfit. Send 25c for your outfit right now; Ld s the t fun-maker youever had. Send at once and get Free e copy of — pan Chemist, so an fnferesting magazine r boys. amateur Chemist’ Catalogue Tt ‘Hand Book “ containing much valuable informa- tion for Boy Chemists and listing many JUNIOR useful chemicals an spyaratus sent postpaid for 10c. None free. = lar ‘*‘CHEMC sy Outfits, $1.50, $3.00 an THE PORTER Fo thmeorcoy co. industrial Arcade, Hagerstown, Md. POSTPAID Raise Belgian Hares for us. Wonderful profits easily made athome. We furnish stock and pay you $7 a pair and express charges and buy all you raise. Also cavies and squabs. Mlastrated catalog and contract Free UNITED FOOD & FUR ASSOCIATION 329 West 48th St. Desk 4 New York

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a DOs PLUMBI & HEATING ¢%3" Send for our big instructive 256 — pose well- bound Handy - Man aie ook Catalog.. Every Home Owner, Contractor, Electrician, Farmer, Factory Manager, etc., needs it. Shows.over 10,000 Fixtures and Supplies in plumb- ing and heating at wholesale. Shows how to save skilled labor, hard work and unneces- sary material by Our New Cut-to-Fit Method This wonderful book helps you select and install the proper Plumbing, Water Supply Sys- tem, Hot Air, Water or Steam lant. Besides being our holesale Catalog it’ has many practical plans, diagrams, sketches, elevations, etc., showing how to do the work this newer, cut-to- fit way. Any handy man with a few tools can easily do his own installing with the aid of this New Handy-Man Book ‘We have spared no effort and have gone to a great expense to compile thisvaluable book. With economy still a neces- sity, it would be unpatriotic to send this expensive book broadcast to non-interested parties. Therefore, we request a temporary deposit for each copy of 25c which we refund on first order, or we send our ain Bulletin FREE. Address Today Hardin-Lavin Company : 40 years at 4526-36-D Cottage Grove Avenue .. Chi go $500,000.00 plants behind our guarantee NG CATTINIESTITITE RIT et * ttt Challenge Cleanable Collars Save Laundry Dollars They give you all the style, snap and comfort of the average collar with the added advantage of being instantly cleaned when soiled. Pere spiration, dust and grease proof— non-wilting. Fine for motoring, sport, dress or business. Look them up. If your dealer can't supply you write us. State size and your favorite style and send 35 cents for sample. THE ARLINGTON WORKS Owned and operated by E. I. du PONT de NEMOURS & COMPANY (TERUITIIESIIIT ESTE PESITITIESIVGIESINIE high positions and big and publiclife. Greater opportunities now thanever. Bealeader. Lawyers earn $3,000 to $10,000 Annually Sretents carey Lb 3¢ vain; books free. Send my inide aad widen LaSALLE EXTENSION © Dept. 783-L Chicago, Il. Popular Science Monthly Secret Wireless Receiving HE advent of the electron relay or audion type of amplifier has made possible a number of useful receiving methods which were imprac- ticable in the & ) early days of wireless telegra- phy. Among ten turns of insulated copper wire, about 24 gauge, strung in a vertical plane within the receiving room and with its height equal to the distance from floor to ceiling. Its plane should be in line with the direction from which it is desired to receive. As shown, its terminals are connected to a series variable condenser C, and a variable primary P of an inductive coupler, LOOP : these rejuven- L ] ated ideas is ¢ — C's ox ile A-1 AN 5 C' ; : = C-2 r ae FIG.4 With simple loop antennae, of the type shown above, concealed within an ordinary living-room, it is now possible to receive interesting messages from long distances that of receiving wireless messages from long distances, by. means of en- tirely concealed absorbing antennae. With a few feet of wire strung around inside a room, it is possible to hear messages arriving from stations many hundreds of miles away, and even to determine in just what direction the transmitter lies. The U.S. Department of Commerce, at the radio laboratory of the Bureau of Standards in Washington, has been working on secret receiving devices for radio telegraphy, and the Navy De- partment is understood to have spent some time on similar investigations. No information has been given out as to the specific instruments used by the investigators attached to these two branches of the government, but it is generally assumed that some form of the magnetic loop antenna has been utilized. Mr. Frederick Kolster, who is the radio engineer of the Depart- ment of Commerce, is credited with the receipt of messages from Germany by the use of simple loops of wire erected within his laboratory and properly tuned. . Other inventors and experimenters have also been giving some attention to this matter of concealed receivers. At Union College, Schenectady, New York, Dr. Ernest J. Berg has tested a small, magnetically-operated receiving antenna which not only receives mes- sages arriving from considerable dis- tances, but also indicates the approxi- mate direction of their travel. He has pointed out that not only can an aerial of this sort be built for much less money than a tall structure of the usual kind, but that it is effective in receiving messagesthrough atmospheric interference which would be exceed- ingly troublesome with the ordinary high masts. The directive feature also helps to eliminate interference from nearby stations which are out of the imaginary line connecting the receiver and sender. A good arrangement for experi- mental work of this sort is shown in Fig. 1. The large loop is made of about 116 The secondary S of this coupler has itg terminals shunted by a tuning-con- denser C2, and leads to the grid- condenser C3, of an audion-detector A;. The filament and plate circuit batteries, B, and B., are connected in the usual manner; the variable 10-ohm rheostat R, is provided for regulation of filament temperature. The plate circuit of the audion- detector, instead of containing a pair of telephones, passes through the prim- ary of a high resistance iron-core “Intensifying Transformer’ at I.T. The secondary of this instrument leads to the grid of an audion-amplifier, A», through a grid-circuit battery B; which serves to keep the grid potential at the best point for amplification. The plate circuit of this amplifier contains the telephones, 7’; the uses of the batteries B, and B;, as well as of the resistance R2, are clearly shown by the diagram. In adjusting the amplifying set it is usually found that critical settings of the batteries B., Bz; and B; and of the resistances R,; and R2 are necessary to give the best signals. To find these adjustments easily, it is most con- venient to use a test-buzzer to excite the loop antenna in the usual way. If the test-buzzer is attached to a wave- meter circuit and thus produces high- frequency oscillations, not only can the detector and amplifier be adjusted, but the primary and secondary circuits can be tuned for any desired wave- length of reception. The single loop arrangement is most effective for receiving from stations located in its plane. If two loops are set up at right angles, as in Fig. 2, it becomes possible to receive from sta- tions located in any direction from the receiver. The diagram shows these loops of a single turn each, for the sake of simplicity. In practice they should be of ten or twenty or more turns of wire. The best number of turns to use will depend upon the wave-length being received, as well as on the area enclosed by the turns, and can best be determined by trial.

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3 its -On- rid- ctor cuit 1 in hm ‘ion on- air ore age n- ite [@- >a RR July, 1919 SAV When Buying Jit Auto Supplies | 100 Page Book Will Show You How Bargailt Prices Over 2,000,000 motorists will see this Look. We want go to see it, too, ve low prices on well known ai hav d the eyes of autoists ~7 over ee U.S. “They buy from us be- cause they save mone;;—that is the only reason we can expect your ovder. Over 2,000 selections to choose from —-tires, spark plugs, batteries, bumpers,wrenches, spotlights—in fact, practical- ly everything you will need. Compare ourprices, Reduced Prices on Riverside 5,000 Mile Auto Tires ide Tices are now priced the lowest th ey ol in months, This new FREE book tella all about them--the prices prove Riverside Tires give you ‘*Most for the Money.” Write now for our FREE copy of this book. Address the 38 nearest you. Kansas City = Fort Worth Portland, Ore. MME Um cd S rns varsecesuuasnnsuncesesesissennsts SHUUTETAGLAUDANANL Your Investment Opportunities under the Reconstruction Period The foundations of many future for- tunes are being laid through the judicious purchase of dependable securities at prevailing low prices. Every indication points to higher levels for meritorious stocks and bonds: A twenty page publication issued fortnightly citing unusual opportunities in the stock market, free upon request. Write for 5-PS., including our copy- righted booklet describing ‘‘The Twenty Payment Plan,” the original easy-pay- ment method of acquiring good values. SALTER EG ar... Securities 40 Exchange Place, New York f]2Week ay OR pays K . Black Beauty Don’t buy an ordinary bicycle. Get the Black Beauty—factory wholesale price. Magni- #f ficent 2 vey Strongest, raciest in # all cycledom’ Five-year guarantee. BN) 18 Exclusive Features See the wheel before paying a cent. Get our Catalog; select #7 your model. 20 Styles. Weship J} at our own risk. Keep or return, No waiting to save up money, onths to pay—sma!! amount on acceptance, then $1 a week. + Get our fac- Sundries $0 ow i*:; first. Lowest in the country. Tires, lamps, horns, etc. Every-&. ; thing for cyclists. Free Sundries Catalog. ¥ HAVERFORD CYCLE CO. jf Dept. G-65 Philadelphia Beautiful New \ BALL Catalog incolers ™ OF). am bows, Bul Build This Car. This nitty little car driven by gasoline motor, can uilt by = aon camee "by us and are very cheai Send 26c for Building fans ond) price list of parts showing how to build this lad’s car. Is Record os | this Car | Sra a TOLEDO, OHIO When two loops are used, their effects may be combined on a radio- goniometer of the sort used by Bellini and Tosi. This is a somewhat com- plicated instrument for the experi- menter to construct, however, and for preliminary work a switching scheme as shown in Fig. 3 will answer well enough. Four single-pole double-throw baby knife switches are mounted on a 2 Fig. 2. Two loops at right angles enable the aerial to receive from every direction nv 3 board, and their terminals connected to the ends of the loops 1 and 2, 3 and 4, and to the primary condenser and inductance, exactly as shown. This wiring plan makes possible a number of combinations; for instance, to use the loop with terminals 1 and 2 alone, switches A and B are left open, while C and D are placed into the upper position. To use the loop at right angles alone, C and D are placed in the down position, A and B being left open. If all four switches are “up,” the loops are connected in parallel in one relation; if all four are down, they are in parallel but in the inverse phase relation. To put the loops in series, leave A open, turn C down.and Band Dup. On examina- Switching arrangement for obtaining best use from two-loop aer- ial. Many combinations are possible, permitting very wide experiment fr) 3 F1IG.3 4 tion of the diagram, still other com- binations of connections will be found possible. The combination of audion-detector and amplifier is so much more sensitive than any detector used alone that even with these small loop antennas com- paratively long distances can be covered. By using additional steps of amplification. still better results can be obtained; and sustained waves may be received by using the heterodyne plan of generating local oscillations and combining them with the incoming signal. The detector circuit of the inductive coupler may, of course, con- tain a regenerating audion or any other responsive apparatus. In fact, experiments with the ordinary crystal- detector are satisfactory for short dis- tances. In building the loops, the turns should be kept separated throughout by an inch or two, so that the capacity between them will be minimized. Thus each loop becomes a veritable tuning-coil of great diameter and short axial length. 117 vr Herman Style 44 Munson Last Tan Russia Calfskin rag Ss Send for ae al Catalogue eee * ie wasn’t so much the wear of their Army shoes that made the conspicuous success of the American soldiers’ foot- wear-in Europe. It was their natural fit and their incom- parable comfort. wn > The Herman Shoe Company made hundreds of thousands of pairs of those Army shoes. We make millions of pairs of | x civilian styles on the same Munson U. S. Army lasts. These shapely civilianized military shoes—built of the best leathers obtainable and with the best of New England workmanship—are recognized everywhere as automatically perfect. Sold in 8,000 retail stores. If you are not near one, we will fit you correctly and quickly through our MAIL ORDER DEP’T at Boston JOS. M. HERMAN SHOE CO.. 802 Albany Building BOSTON, MASS. SS + eg tH Made in 17 leads, one for every need or preference if i 8 a Onesof the Eldorado leads is your | lead—just fitted to the work you do 8 and the way youdoit. Finc this pencil. €|| You will find that you can do better 3|| work and faster wotk, and will be less fatigued after a hard day’s work. Our grade chart will enable you to select your favori:e lead. Write for it today. Get a trial dozen from your dealer or send us 1sc for full size samples worth double the money. Please mention your dealer’s name and whether very soft, soft, medium, hard, or very hard lead is desired. Oe JOSEPH DIXON CRUCIBLE CO. sea Dept. 120-J Jersey City, N. J. There is a Dixon-quality Pencil, Crayon, and Eraser for every purpose. Ge /ouad MMMNCIP 421SCUi ay) =

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Popular Science Monthly The Construction of a Rotary Tuning-Coil Psst a base is made of hardwood measuring 8 in. square by 1 jn. thick, as shown at A in the illustra- tion. A ring B is next sawed from 1\4-in. stock, 7 in. in diameter with the rim 1% in. thick. Shellac this ring thoroughly and while it is sti] tacky, wind it with a single layer of No. 23-gauge double cotton or silk- covered magnet wire. The wire must be wound tightly and the turns should

SURGEON @ Make $2,500 to $4,000 Per Year Giving New Life to Old Tires A Haywood Tire Sur- geon can do more with old tires than was even dream- ed before the war. By the Haywood Method a Haywood Tire Surgeon can give 4,000 to 5,000 more miles of new life to a tire that two years ago would have been thrown on the junk pile. And it’s easy to learn. Stations are Needed Everywhere 20,000,000 tires wearing down every day. - By Tire Surgery you can quickly repair, rebuild and give new life to tires seemingly all worn out. Cuts, gashes, tears, bruises, broken fabric, every kind of an accident that can happen to any tire, inside or out, you can repair and save for long service. The chance to make money is simply wonderful. $2,500 to $4,000 a Year is Possible If we told you all the truth you-wouldn’t Believe it. : You wouss —_ true.” But you can see what a great fie ere iox ‘ae Roe ey ior this better way. ‘Send Today for My Free Book I have ready to mail you the day 4 I get your request,afascinating / k—all about tires—how

Four Months This is Richard A. Oldham . Oldham was te. graph tor for the Illinois Central Railroad for twenty genes. He is fifty-eight years old. Oneday read one of my advertisemen’ —_ of making money in A jurgery business. In a few weeks he purchased and installed a Haywood outfit. Se See ns One-Half years ‘as Telegraph Operator.

Stet

a Ia :

Details of rotary tuning-coil. The con- struction is simple, careful winding of the ring offering the greatest difficulty

be made close together. After the Mg i shellac is thoroughly dry mount the torepair them by the Hay- ; 2 f ‘®, wood Method—how to ring on the base with very small wire M. HAYWOOD, President @, start in business—how Seema

to build up trade— i HAYWOOD TIRE & EQUIPMENT CO. ‘¢ what to charge. in.48 nails. Care must be taken not to DEAR SIR: Please send me by return mail your @'tie wich yaicartne AVA Toi ee ee ee eee : Please ‘ whole propositio , o the base. e best way to do this boo the new Haywood Tire Surgery Method in front of you. Use #3 q “ a iret tee details of your tres school of tire alee =. at o left. is to put the nails in the ring before j. tayw i. Pres. Haywood Tire &

ANTENNA Name '@, Equipment Co. 626 Capitol Ave. 4 Address %

, indianapolis ¢ indiana Indoor Toilet DETECTOR TELEP \ A \

MAKE YOUR BIKE A

WW; ‘ TUNER’ SC Zed S mS,

stalled. Convenient to move. Con- [Hii tents disposed of easily as garbage. Prevents fly breeding and water con- ci f Tne Comfort Closet tor Homes, ¥ c ~~ Summer Cottages and Camps. } Sa@G. eg suet. ee _— a } : . tr icals dissolve >= Py =e =“) contents; kills all germs. Easily in- SS FOND ve (ITN) hii rj at asmall cost, by using \\\ A, Var ourattachable outfit. Fits any Bicycle. Easily at- tached. No special tools required. **Used His Four Years”’ Harry A. Hyatt, of Boreas River, New York, writes: ‘‘About four years ago I received my motor attachment, How the rotary tuner is connected to a typical circuit. No great changes from the ordinary are necessary tamination. Provides sanitary, odor- 1M less toilet in home protected from cold Jalil | and stormy weather. Only closet with mM porcelain container. Easily cleaned. Cia): Vil] ae Ne by gg fren —<e 30 z ays’ Free Trial. ents make $60 to ; ; : : : $100 weekly. Exclusive territory. Ask for booklet-—FREE winding on the wire. The ring is Comfort Chemical Closet Co., 1327 Factories Bldg., Toledo,0. } | raised from the base with small blocks C, through which the nails pass. A

[SUPERIOR SINCE 1904)

me good service ¢ wanting Over 100,000 in Use OF GoldenG em hard rubber or fiber knob D is fastened ommend them to the Shaw Manw/ac- (| Adding Machine | to the base as shown, so that it will vied ae K. Wits today tor bargain Ie choc memiaalccations |; (EES turn. A. contact arm E is secured to FREE BOOK iertednceboskice falls Weltefor t0-dey Trial Otic: (ana ERE the knob. The insulation is burnt or describing the SHAW Bicycie Motor At- : Pe deeds 3 9 § / : ° tachment. Motoreycles all makes, new MB. Ganchor, A. A. W. Co. 1 i {BG |B scraped off with a knife where the Sige ett Canadian Agency Wl cusuucescziawoe —] Man contact arm touches the wire. The SHAW MANUFACTURING CO. two ends of the wire are connected to Dept. 169 GALESBURG, KANSAS

the binding-posts F and G. The con- tact arm is connected to the binding- post H. The connections are shown in the diagram. Any detector may be sub- stituted for the crystal-detector in the diagram.— MALCOLM K. GORDON, JR.

118

<i sae Nes Kaa a Rie nl ARTIS SE tk oe bet

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ee e e amo e WASSER LE OE LL RN MERRIE GI ARB SC ee ee July, 1919 AN EASY WAY TO MAKE MONEY -2::': dent. Go i od my~ 4 independent. o in the tire re- pair ye ‘ one man Bays “*I made $60.00 the first ” Others, average $200 to ved Wrapped Tread Method sed by Tire Manufacturers Does d work as the big hig’ “vuleanizing outfits. boy can use it. It’s the only vulcanizer t has Automatic Heat Control, and can’t undercure or overcure & tire. Requires no watching or regulating. FREE Book “How Tire Repair Shop.” It +A cag _make ig money. Don’t delay. Write quick. C. A. SHALER CO. 2106 Fourth St. Waupun, Wisconsin — Two Uses from _ One Socket Get two conveniences from single electric light sockets with the eee i. BENJAMIN ELECTRIC 4\\ MFG. CO. j Chicago New York R San Francisco rare Pocket Tool Chest Strong Knife Wire Pliers LetkerPunch Hoc! Hook 9 Lools SweazingAuwl Wire Cutter Screw Dricer Screw Bit Alligator Wrench Each a strong, practical tool. As easily carried as a 3-blade knife, and has nomore parts. WG Length, 4in. Pliers and wire cutters are drop-forged tool steel—cut barbed fence wire as easily as 8-inch pliers. Blade is tempered cut- lers’ steel. Each tool works independently, Once used, always carried by Electricians Railway Men Motorists Mechanics Horsemen Sportsmen Sent postpaid in U. S. for $1.75 (add Sc if insured). Highest quality construction, fully guaranteed. Elican Specialty Co. ®7° Werchants, Sank, Bide. Elican Wunderknife We want every man who shaves to write us for rticulars about the Vibrating Electric Razor. © matter where you live, in_the city or on the farm, the Electric Safety Razor will solve your shaving troubles. VIBRATING ELECTRIC RAZOR CO. Dept. 137, Omaha, Nebr. eres € 6 ee es ¢ ee ee ewe. Send Your Send You a Lachnite ON’T send a penny. Send your name and fin i DB and say, ‘‘Send = res mounted ina solid ial.’’ We will send it Neleewe cc Hee & e' + If you return e urn r deposit, If you decide t $2.50 a month until $18.75 is paid. Send name now. Tell us whic’ Write Today 977932 rT eee Tings you wish Uadies’ or men’s.) Be sure to send your finger size. Harold Lachman Co.,12 N. Michigan Av.,Dept.B120, Chicago s*e¢ecgseeoeeoenrueeeveee Simplified Portable Receiver for Radio HE portable receiver shown in the illustration should be very desir- able to any operator who wishes for a small radio receiver that is substantial and compact, and at the same time not only has a broad range of tuning but requires very little attention after being once adjusted. It is complete within itself with the exception of a Gi Gb oO | A receiver of this type combines simplicity with portability, . compactness with broad range pair of head telephones, antenna and ground connection. When this set is used in connection with a portable antenna, which of necessity has a low capacity, it is not necessary to secure a ground connec- tion. Asa result the set may be used anywhere, regardless of the condition of the soil, or whether it be moist or dry. There are no sliding contacts or loose couplings to bother with. With a single wire antenna strung from a high cliff, rock or tree, preferably 400 stations heard will come in stronger without a ground connection, The first thing to be considered is the little box or case that contains the inductance, condenser and detector. It is made from 4-in. quartered oak, the inside dimensions being 6 in. long, 3 in. wide and 2% in. deep. The hinged cover is l-in. deep to allow for the space taken up by the rubber knob of the inductance, the detector and binding posts, the bases of which are flush with the upper edge of the case, as shown. A small catch-lock is pro- vided, which gives the set a neat and business-like appearance, and obviates the use of a strap to keep the case closed when held by the brass handle on cover top. The inductance consists of approxi- mately 140 turns of No. 22 single cotton-covered copper wire wound on a fiber or card-board tube 2% in. in diameter and 2 in. long. A soldered connection or tap is taken off at every twentieth turn and soldered to a lug of a 7-point switch. 119 Typewriter Sensation or 500 ft. long, 80 per cent of the | Free Trial Use as You Pay Only $4.00 a month until the low total price of $53.15 is paid, and the machine is yours This is absolutely the most generous type- writer offer ever made. Do not rent a machine when you can pay $4.00 a month and own one. Think of it—Buying a $100.00 machine for $53.15. Cash price, $50.85. Never before has anything like this been attempted. Standard Visible No. 10 SMITH PREMIER Perfect machines, Standard size, full 84 character one motion keyboard. The entire line of writing completely visible at all times, has the tabulator, the two-color ribbon, with automatic reverse, the back spacer, ball bearing type bars, ball bearing carriage action, in fact every late style feature and modern operating convenience. Comes to you with everything com- plete; tools, cover, operating book and instructions, ribbon, practice paper —nothing extra to buy. You cannot imagine the perfection of this beauti- ful reconstructed typewriter until you have seen it. I have sold several thou- sand of these perfect latest style Model No. 10 machines at this bargain price and every one of these thousands of satisfied customers had this beautiful, strictly up to date machine on five days’ free trial before deciding to buy it. I will send it to you F.O. B. Chicago, for five days’ free trial. It will sell itself, but if you are not satisfied that this is the greatest type- writer you ever saw, you can return it at my expense. You won’t want to return it after you try it—you cannot equal this wonderful value anywhere. You Take No Risk—Put in Your Order Now When the typewriter arrives deposit with the ex- press agent $9.15 and take the machine for five days’ trial. If you are convinced that it is the best typewriter you ever saw, keep it. and send me $4.00 a month until our bargain price of $53.15 is paid. If youdon’t want it, return it to the express agent, receive your $9.15 and return the machine to me. I will pay the returnexpresscharges. This machine is guaranted just as if you paid $100.00 for it. Itis standard. “Over one hundred thou- sand people own-and use these typewriters and think them the best ever manufactured. The supply at this price is very limited, the price will probably be raised when my next ad- vertisement appears, so don’t delay. Fill in the coupon today—mail to me—the typewriter will be shipped promptly. There is no red tape. I employ no solicitors—no collectors—no chattel mortgage. It is simply understood that I retain title to the machine until the full $53.15 is paid. You cannot lose. It is the greatest typewriter opportunity you will ever have.. Do not send me one cent. Get the coupon in the mails today—sure. HARRY A. SMITH, 306, 218 N. Wells St, Chicago H. A. SMITH, 306, 218 N. Wells St., Chicago, Ill. Ship me a No. 10 Smith Premier F. O. B. Chicago, as described in this advertisement. I.will pay you the $44.00 balance of the special $53.15 purchase price, at the rate of $4.00 per month. The title to remain in you until fully paid for. It is understood that I have five days in which to examine and try the typewriter. If I choose not to keep it I will carefully repack it and return it to the express agent. It is understood that you give the standard guarantee for one year. CR meee eee meee eee eee HHH EEE HEE EHH Ee eee ESS EHESE®

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6 sizes in one tool AX your Supply House about Oster Bull Dog Die-Stock No. 102 for pipe— sizes 34, 44, 34, 1 and 14 inches. Illustrated Catalog on request PIPE THREADING THE OSTER MFG. CO., CLEVELAND, OHIO. (SESS SE Radio Apparatus Catalog Sent Postpaid on Request Large Stock Everyone interested in wireless should have this book. Pages and pages of radio apparatus and parts of high quality, late design, at a price t will be a pleasant surprise. Satisfaction guaranteed or your money will returned without question. Write for our Radio Appa- tatus Catalog.No. 9110P. Sears, Roebuck and Co. Chicago, Ill. Why spend dollars for repairs when cents will do? Write for this free book and learn how SMOOTH-ON IRON CEMENT No. 1 (50c a lb. at Hardware. _. and Auto: Supply stores) will save you money. SMOOTH.-ON MFG. CO. Jersey City, N. J., U.S.A. No Matter Where y’ $ the Leak SMOOTHO AY Will Stop It. EE $2 io as 30 MONTH ! TD Py 12 Sewell asin’ This month’s Bulletin 3: »> HARRIS-GOAR COMPANY Dept. 357 . KANSAS CITY, MO. In taking taps from inductances of any description it should be noted that the turn of the coil itself should not be brought up to the lug and then back to the tube to complete the turn again. There are at least two good ways of taking taps from coils; one is to bare some of the wire on the turn for about lj in. and solder a separate wire to it. A second method is to double back about 5 in. of a turn, scrape bare the lower extremities and secure by twist- ing them together. In both cases the connection should be soldered and taped or shellacked so that the ad- vancing taps will not short circuit back on each other. Taps of this character do not disturb the continuity of the coil nor cause undesirable capacity effects. After the inductance is finished it should be thoroughly painted with insulating shellac or varnish, especially the soldered con- nections. The stopping condenser may com- prise any small fixed condenser suit- able for radio circuits, provided that it fits easily into the case with the inductance. One may be constructed by using 10 sheets of heavy tinfoil, or extra light sheet brass 114 in. by 234 in., separated by similar sheets, slight- ly larger, of paraffined or oiled paper. Connections are made as shown in Fig. 1, care being exercised in as- sembling the parts into the case, so that no exposed connections are in any way short circuited. GROUND ANTENNA oo i @ WNDUCTANCE *0e SCL. 7JAPS OF 20 / TURNS EACH ON TUBING 24 DIAM. 2°LG. STOPPING COND. » FIG.1 Details of the interior wirings of the port- able receiving set. Use care in assembling The detector is composed of a small silicon or galena crystal soldered in a little brass cup, which in turn may be secured in a larger cup by small set screws projecting from theside. Rest- ing lightly on the crystal is a fine steel wire soldered to a brass rod that moves back and forth, and also turns, in a small binding-post. A small knurled rubber knob on the opposite end of the rod permits adjustment of the detector. Two binding-posts are provided for the telephone tips, while two extra posts may be used to connect in different detectors as desired. Referring to Fig. 2, it will be noted that the inductance, condenser and detector composes a closed circuit. This arrangement gives much the same effect without the ground connection’ shown by the dotted lines when used on an antenna of low capacity, such as a single wire suspended in the air. 120 Popular Science Monthly When the set is connected to a ship antenna or one of similar capacity the ground binding post should be used to get the best results; otherwise the incoming signals will be weakened, When the set is to be used in the country or mountains, nothing more igs needed than a spool of light, flexible ANTENNA a CAPACITY CIRCUIT Lo DETECTOR VARIABLE _-*” INDUCTANCE CONDEN se R 3 1 ul PHONES FIG. 2 = Schematic representation of the portable’ receiver connected to a typical circuit, i lh wire and the telephones. To obtain a good height for the antenna, tie a stone to one end of the wire, then swing the weighted part up into the top of a high tree and lead out wire for 400 or 500 ft., securing it to a stick or some convenient support before con- necting to the antenna binding post. Connect the telephones and set the switch on the second or third point. Adjust the detector several times. It should not be long before signals from distant stations are heard. In case a ground connection be- comes desirable a very excellent one can be obtained by driving a new 8-penny nail into the side of a living tree, near the ground, and leading a wire from this to the set. The roots of the tree are full of moisture and extend in all directions, in many in- stances deep into the earth. The writer obtained very good results with this little portable instrument on the Southwestern coast of Mexico, where the character of the country is ex- tremely barren and rocky. A single wire was stretched from a _ rocky pinnacle about 200 ft. high, down to the edge of a small lagoon. Signals from the United States at night were clear and strong. Amateurs in all sections of the coun- try are finding that the vacuum valve type of detector, or rectifier of electric waves, is permitting them to do many things impossible in the old days. The valve, properly adjusted, is so much more sensitive than crystal detectors, and is capable of so much wider per- formance, that they find much of in- terest in rigging up vacuum tubes to take the place cf,.and compare with, crystal detectors. The extra detector binding posts on this set are convenient for experiment along this line. They enable typical vacuum valve circuits to be arranged and then connected in on this portable receiving set without dis- turbing the existing wiring on the ap- paratus. Amateurs will probably enjoy affixing other features to the set to add to its flexibility STANLEY E. HYDE. er a AER RMIRRTA 79

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A OO wr KY E. CLP AM EO isha ABR SSTIE AEE BERS LDA STA RINE amma July, 1919 Playing Checkers by Wireless N amusing method of playing checkers, which, by the way, is highly instructive in learning wireless operation, is to provide two complete sets of checkers and boards with the spaces numbered and the men lettered as shown in the illustration. When Now comes the checkerboard wire- less, which is highly instructive for beginners and amusing to anyone the apparatus is adjusted, one player takes the men from A to L and the other player from M to Z. The first player telegraphs ‘‘Move L from 12 to 16,” whereupon both players make the move. Then the other player might telegraph “Move O from 23 to 19.’”’ Both move then “Jump L from 16 to 23, etc.,”’ until the end of the game is reached. It is very evident that the game may be interposed with telegraphic exclama- tions thus making interesting practice. This scheme may also be used with telephone or ordinary telegraph. Or it may be played by a bed patient unable to sit at a table, who may call the moves from one bed to an- other.—VicToR TODD. One Bell with Two Push- Buttons HEN one electric bell is used to indicate calls from two different places, such as the front and back doors of a dwelling, it is rather difficult to determine the source of the call. Two push-buttons on one bell is an old trick, but one that few amateurs know This can be remedied by connecting, as shown in the diagram, where one button causes the bell to act as a single stroke bell and give one tap on the bell every time the button is pressed. The other button will give the regular trembler action.—THOMAS W. BENSON. POSITION | SALARY AUTOMOBILE A ENGINEER 25 wax REPAIR MAN |S5)Q)) warn CHAUFFEUR |*9Q() witx )! Put Your Name On This Pay-Roll Men like you are wanted for big-pay positions in the fascin- ating field of automobile engineering. We have made it easy for you to fit yourself for one of these positions. You don’t have to go to school. You don’t have to serve an apprenticeship. Fifteen automobile engineers and specialists have compiled a spare time reading course that will equip you to be an automobile expert without taking any time from your present work. AUTO BOOKS 5 Volumes Shipped Free Now ready for you—an up-to-thé-minute five-volume library on Automobile Engineering, covering the con- Partial List of Contents Explosion Motors Welding Motor Construction and Repair Carburetors and Settings Vaives, Cooling : Lubrication struction, care and repair of pleasure cars, motor | Eiy,Wneels trucks and motorcycles. Brimming over with advanced Tranemleston n information on Lighting Systems, Garage Design and _ | Steering Frames Equipment, Welding and other repair methods. Con-_ | Tires "4 4 i : Vulcanizing tains everything that a mechanic or an engineer ora_ | Ignition : ° Starting and Lighting motorcyclist or the owner or prospective owner of a Systems i . 4 Wirt Diag 8 motor car ought to know. Written in simple language | Sse piperam American Morocco, flexible covers, gold stamped, 2,400 ae pages and 2,000 illustrations, tables and explanatory dia- Casnend aleade Motorcycles pile but that comes to you free for 7 days’ examination. | Gioss Only Tc a Day Not a cent to pay in advance. First: you Just mail coupon and pay express charges when books arrive. You can read them and study them for seven whole days before you decide whether seven days and $2 a month until the special introductory price of $17.80 has been paid. (Regular price $25.00.) Along with the set goes a year’s price $12.) This great bargain offer must soon be withdrawn. offer for you, that we urge you to waste not a moment in sending for the books. Put the coupon in the mails today. Send no that anybody can understand. Tastefully bound in Commercial Garage. Storage Batteries grams. A library that cost thousands of dollars, to com- peter ary see the books in your own home or shop. you want to keep them or not. If you like the books send only $2 in consulting membership in the American Technical Society. (Regular Don’t take our word for it. See the books without cost. There is so much profit in this money—only the coupon! American Technical Society Dept. A 20 B, Chicago, III. a ee American Technical Society, Dept. A 20B, Chicago, Ill. Please send me the 5-volume set, Automobile Engineering, for 7 days’ examination, shipping charges collect. If I de- cide to buy, I will send $2 within 7 days and the balance at : $2 a month until the $17.80 has been paid. Then you send me a receipt showing that the $25.00 set of books and the $12 Consulting Membership are mine and fully paid — With every set is ineluded— FREE for. If I think I can get along without the books after —a Consulting Membership which i the seven days’ trial I will return them at your expense. gives you the privilege of submit- ting your perplexing problems to Al a corps of experts for an entire year. Ei This Consulting Membership regn- 4) larly sells for $12.00. 121

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Popular Science Moni That Canvas Camp in the Woods ANVAS houses By George M. Petersen _ breeding-place for in. are often referred sects. Level ground, to. as tents, but nothing is further plenty air, and cleanliness around the from the truth. A canvas house, house will do much to keep away al] Putting a wire band properly speaking, is a wood frame or kinds of pests. ona pail-It's easy with skeleton over which is stretched canvas The floor should be supported upon Wed Devils. to keep out the posts or concrete weather. The piers, and these house shown in should be level sa ; oi the illustration is across the top so a5 of Steely nearly ideal both that the entire Ningens as to size and floor rests evenly comfort. The floor for upon them. that make hard jobs this house is made The walls are then constructed in four sections, easy. They Save yOur |} | each section being in sections, ag shown in the draw- . iain ten feet square to hands and patience no age ings, each section especially when your |] | ling. Each section being bolted to -bare hands won't do. is complete in it- the floor and to each adjoining sec- self, and the four parts are bolted tion, so as to make the building rigid 4 4 together as shown _ te SES es and strong. Each al i’ to form the floor Sin een eneniiies thn eter dapenine ven wallsection should 4 of the house. had that camp? Why don’t you have another be covered with ara ue par nee / The joists are thissummer? Here it is. Get busy rightnow 14-mesh or finer first framed to- galvanized screen- Pp L I E. R & gether as in A, and are thencovered ing put on the outside of the studs. with 14-mesh galvanized-wire cloth or By covering the walls of the entire screening to prevent mice, squirrels, house with screening the canvas may be . wa . and other small animals from boring rolled up once or twice a week and the ety mak eee oP a a up through it. A layer of tar felt could whole house aired without any trouble. want to force into hard wood, be laid over the screening to good ad- For the window spaces it is well to that wire you want to bend. vantage, and it would assist greatly in use 22- or 24-mesh wire cloth. This keeping out small gnats, mosquitoes, fine mesh screen will turn even the One of the many styles is just and other insects. It might be well to hardest rain and make it unnecessary right for your purpose. Ask your suggest that the floor ||| dealer to show them to you today. be kept at least two FRONT ELEVATION . feet above theground, fF ~- Toe) el ii ee mH IN 1 1 Tt Shy Antenne angtng e leveled ee een roe met yo si Ad 2 at rey [It build than it looks The ‘‘Red Devil’’ Tool Guide | at'4’ to be in the plans. Write for it the house so that no flies |, |e fo ko fe Two people can moisture can accumu- il? fs easily erect it in late and forms TH NETIECETL|) secs tn: SMITH & HEMENWAY CO., INC. . Oo" 1 4. cAW.COTH 264 Broadway, New York City Factories: Irvington, N. J. **Red Devil’? is the Expert Mechanic’s guide to Known Quality in Pliers, Elec- tricians’ Tools, Hack Saw: Frames and Blades, Auger Bits, Chain Drills, and other Hand Tools, all of a class with ‘‘Red Devil’? Glass Cutters, the biggest sellers in the world. in BATTERY CHARGING HB Lighting & “Charging Set sturd it mak Bs eet te the | Why FELT BETWEEN CLOTH & ii YELLOW NE FLG. LEFT SIDE ELEVATION RIGHT SIDE ELEVATION PROFITS tbat ‘battery tes from line Small _ Pa ag Puts this Money ~~ Maker 4 in Your Garage 5 BOLT easy terms. Ae | W AY for informa- tion ices. Let our al your echoed mast Rae Hobart Brothers Co. Box $73 Troy, Ohio ment eaeeeere COVER ALL STUDS AND RAFTERS WITH GALV. WIRE RAFTERS THE CONSTRUCTION OF SMALL | conrionswim wire] (COM ON OUTSIDE ox4 ALTERNATING CURRENT MOTORS | oo me ged See Set LR. 5 ee neg ae Sx BOW THIRD RAFFTER 7X4 RAR ELEVATION FLOOR PLAN & LAYOUT SPACE RAFTERS 2'C-t0C. BOLT RAFTER & WALL PLATES TOGETHER ABOUT EVERY 4 ‘ By A. E. WATSON EET Professor of Electricity Brown University and a Well-known Writer on Electrical Topics. 79 Pages, 47 Illustrations. Price, postpaid, $1.00 Popular Science Monthly, 225 W. 39th St., New York - ROOF CONSTRUCTION 122 AON EMEA IOABE LE: DORE LEI NOEL IE + a

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|= i, ie 1 ld oks ns. can ich Sil | o_ii} Ht Ph ttyl I Se A, NENA ELOY ELSE LIE IEE ES EIS 1 Sano eR July, 1919 close the canvas windows. Such a alba also insures freedom from the little insects that come through the ordinary 14-mesh window-screen. Finishing the Roof The roof is framed as shown in the roof construction drawing, the rafters being securely spiked to plates both at the ridge and at the eaves. Provision is made for bolts to draw these sections together, first at the ridge and then to the wall plates. The tops of the walls are prevented from spreading by the truss which is bolted to every third rafter. It is well to cover the rafters with screening also, as it greatly saves the canvas by taking the strain off it between the rafters, preventing the canvas from being cut by their rough edges. When the rafters are in place and the tarpaulin drawn over the roof, the floor should be given at least two coats of good lead and oil paint to preserve the wood and also to assist in keeping the house dry. This paint should be put on thin and well brushed in if it is to be of any value. The Canvas Cover The canvas covering should be made in five sections—front, rear, left and right sides, and roof. Each wall- section covering is secured to the top wall plates by means of screw-hooks, and stretched down to the bottom wall plates, where it is secured in the same manner. The window openings are cut out and flaps are sewed on to make the two window coverings about six inches larger each way than the openings. The wall covering is but- toned down around the window open- ings, so that the wind will not get behind it and tear it. The flaps covering the windows are also made to button down in case of a big storm or when greater privacy is desired. After all of the wall-section coverings are in place, the roof covering is stretched tight, and lapped at least a foot down over the side walls to pre- vent rain from beating in from under- neath. The roof covering is usually fastened down over the side-wall covering with buttons or screw-hooks. The front and rear doors, and the inside doors as well, may be regular screen doors covered with a canvas flap, which may be rolled up or left down as the case may be. The in- terior partitions can be easily framed to suit individual taste, and may be covered with canvas or wall-board. As this type of building is readily taken down, there is no reason why the inside of the walls should not be covered with a good wall-board, except that it will prevent the proper airing of the building. This whole house, with the exception of the piers, perhaps, can easily be placed in a large van or truck and taken back to the city when the vacation period is over. YOUR OPPORTUNITY om Canceled Government Contracts We have secured a large quantity of Small Motors, Generators and Charging Outfits. This material is new, stillin original cases and carries the full factory guarantee. Sm [his is Your Opportunity to buy new, guaranteed (eine : wate Seen tfits For use on 110 volt, A. C., 60 cycle, single phase current only. 80 watts, 8 volts, 10 amperes . $48. 50 150 watts, 30 volts, & amperes . $68-50 150 watts, 15 volts, 10 amperes . $68-50 to fall oo $00 watts, 30 volts, 50 4 10 amperes . $94- amination. MONEY BACK GUARANTEE Mail $5.00 cash or All outfits complete with switch- ard as cut shown, CHAS. H. JOHNSTON - Ui) B__\. Electrical Apparatus of Standard Manufacture H p INDUCTION eSeMOTOR Hy | 110 or 220 volts, A. C. L 60 cycle, single phase, 1750 R. P. M. WRITE FOR CATALOGUE. BARGAINS IN MOTORS AND GENERATORS. SPECIAL QUANTITY PRICES 22°, POLYPHASE MOTORS iim 110-220 BEPULSION MOTORS 333° Sarvs sera MEW MOTORS 255322 TH 87 MANUFACTURERS’ DISTRIBUTER eS °A.C., WASHING MACHINE MOTOR ALL MOTORS COMPLETE AS CUT cycle,single phase Suitable for oper- ating Small Com- pressors, Coffee ] § 0 Grinders, Bottle Washers, Lathes 1 H. P, 122 votts 1750 R. P. M. AGENTS 22°."/s Gold and Silver Sign Letters For store fronts, office windows and glass signs of all kinds. No experience necessary. Any- one can put them on and make money right from the start. $30.00 to $100.00 a Week! You can sell to nearby trade or travel all over the country. There is a big demand for win- dow lettering in‘every town. Send for Free Samples and full particulars. Liberal Offer to General Agents. METALLIC LETTER CO., 433 N. Clark St.. Chicago West End - PITTSBURGH, PA. | Build Your Own PHONOGRAPH It's Easy With Our Help an SAVE A fom Jepes, inating: wed \ OVER § Se feet toe Coe \ HALF arms, case material, blue prints and full instructions, Plays an: record. You can make fine prof- it building phonographs for your friends. Write Today for Our Free Blue Print Offer Agents wanted for our ready built phonographs ASBESTOS 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. Geta WITTE; Ihave madea big smashing reduce , tioninengineprices—for quick shipment— all styles: sizes—2 to 30H. P.—Kero- | sene or Gasoline--Statio: , PortableorSaw-rig --Buy on your ownterms, { guarantee safe de- livery, make immediate ship t---vuarantee every part of your engine against defects as long as = use — ee we time oe a me at o r prices on this special factory di- ex. Book Free.Ed, H Witte, Pres. rect offer. B . WITTE ENGINE WORKS 2221 Oakland Ave...« « 2221 Empire Bid Pittsbu Violin, Hawalian Guitar ~ Ukulele, Guitar, Mandolin, Cornet or Banjo oe ond new of teaching note music by mail. To pees in each ohn coma Il give a $20 superb Violin, Mandolin, ulele, Guitar, Hawaiian Guitar, Cornet or Banjo absolutely free, Very small charge for lessons only mse. We guarantee success or no charge. Complete outfit free. Write at once—no obligation, SCHOOL OF MUSIC, Dept. 402, CHICAGO, ILL. Every User of Tools Will Appreciate This Handy Bag Made of Harness Leather— Strong and Durable Combines all the good features of the various common 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 24 x 8 inches. Show this ad to your dealer and ask for the genuine KLEIN tool bag. If unable to get it write us. MATHIAS KLEIN & SONS, Mfrs. CANAL STA. 3, CHICAGO

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Look for “The B&S on the Square” | IBS when buying Machinists Tools mark that represents the best known and most it -as= the widely used mach- inists tools. It stands for the quality and that skilled machinists have been demanding for the last 80 years. Brown & Sharpe Machinists Tools you our 27 which il- and describes service idaveleicy.tale mm corel i; very ic b. Write today for this useful book Catalog No, 27 BROWN & SHARPE MFG. CO. PROVIDENCE, R. |., BROWN & SHARPE MACHINISTS TOOLS Popular Science M onthly. How to Improve the Intake Manifold By George B. Gould ID you ever stop to realize what constitute some of the im- portant problems of the present day gas engineer in his efforts to perfect this means of power and locomotion, or have you thought of what has been done toward solving the problems of the gas engine in its progress toward present day perfection? Through this constant striving toward perfection we have seen the evolution of the quiet sleeve valve and the sixteen valve head. Here are the efficient valve and the sufficient valve capacity. If the two could be combined we might, perhaps, be able to rest on our laurels. If, however, we are given a valve or valves of sufficient size to permit enough gas to enter the cylinder on the down stroke, we must next consider, how we are going to get enough gas to the valves. Accordingly I wish to draw your attention to the intake manifold and what may be done toward its perfection on the small, as well as the It has been . re- peatedly remarked —and proven—by engineers connected with the manu- facture of airplane engines that the Tumbling three tumbling operation manifolds at one -—or the smoothing time. Power sup- of the inside surface plied from over- “ head shafting Of the intake mani- fold on the airplane engine—tends toward a positive in- crease in speed of from five to ten per cent. In view of this it is logical to deduce that the tumbling operation will be of great benefit to the Ford intake manifoldand ultimately to the Ford engine. The intake mani- fold, as it is cast and comes from the foundry, is very SPEED 600 RPM rough and uneven : on the inside, and this roughness greatly impedes the progress of the ex- plosive gases on ©) (0) their way toward the valves and the cylinder. Shoot the gases into the cylinder and you will get a snappy and responsive engine. If you have a large valve area and an improper sized 3” PULLEY ON MOTOR or a very crooked and rough passage for the gases to be drawn through, you simply create eddies in the manifold and your increase in speed and power is not very great. But in the tumbling operation you increase the size of the passage through the intake manifold, and, what is still more important, you do away with the obstructions that ar- 124 BELT DRIVE GEAR & FRICTION DRIVE rest the speed of the mixture in its journey toward explosion. Like an old man sighs for the youth that is gone, so the motorist sighs for the “‘pep”’ and accelerating ability that the motor had when new. In the tumbling operation we have a simple and first-class method of increasing the motor’s power. There are some who will say without thinking: ‘“Why not increase the size of the intake manifold to a greater extent?” But you will readily see that this will not \ do, because the = minute you increase = or decrease the size of the manifold to ~ —— wl any appreciable ex- Alimni\, . ent you therebg essen your throttle Tumbling two controlofthemotor, manifolds with a You must remem- proce rd a ber that you want 30 to60 R.P.M. Your motor to slow down under the operation of the throttle lever just as fast as it picks , up. To illustrate this, imagine an extra large-diameter intake manifold on your motor and the throttle open for a quick getaway on low gear; your large manifold fills up with an ex plosive mixture and that’s all very well. Right away you are ready to slow the engine down to shift into high. You close the throttle, only to find the engine keeps on turning over rapidly until it has used up the large supply of gas in the extra large manifold. The result is you either slip your clutch or there is a considerable lapse of time before you can shift into high, and both are undesirable to the average mo- torist. Much the same as the human ma- chine is this present- day gas engine in that the better you enable each to breathe the better How the drive 2nd faster each will speedisincreas- run. Clear your ed or reduced. throat now and see onl bye rane how much better illustrated you breathe, and tomorrow clear out the obstructions in the Ford’s intake manifold and see how much better it will breathe—and run. But how do we go about clearing the inside of the intake manifold? What does this much-talked-of tumbling operation consist of? It consists in the main of taking one or more intake manifolds, filling them half full of a mixture of sand and pieces of jagged iron or steel choppings, fastening them 18” PULLEY 12° PULLEY: SPEED 25RPM _ securely to a large wooden disk and SNAG SNE ROTEL a ¢ i

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th or at le ne a- t- in yu CO er ill ur ee er ad ut ns ee ad he at ng ke ed ‘m nd- Li SAS MEL TRE BIER July, 1919 e o Kerosene Oil, Gasoline and Gas Let me send you an engine to earn its own cost while you use it—for my Kerosene engine gives more power from a gallon of 12-cent_kerosene than you can get from a gallon of 20- or 25-cent gasoline in a gasoline engine—Easy to start; easy to operate; no cranking; no batteries. All sizes—2 H.P. to 22 H.P.—Stationary, Portable, and Sawing Outnts. 10-Year Guarantee on Every Engine. rite for Latest Prices. DIRECT FROM MY BIG FACTORY I started my factory, years ago, [ have been ~~ yong direct from the factory to the man in the shop or on the farm. Now, as before, any Spee -— casino On 90 Days’ Trial ; send out must make good all I guarantee. No need to pay double my price for any good engine, or take an out- of-date engine for any kind of a price. Let me show you how to figure what an engine is worth and How to Know Better Engines My newest book helps you choose a safe and value- received engine—How to make simple tests—and all about valve in head motor. Send me your address today. oe a postal card will bring this newest and latest i saat OTTAWA MFG. CO. iiiwasitins’ 4G eee Start your OWN business $ a and make $10 to $15 an d HOUR, or an average of ay With one lathe, fitted with a ‘* PERFECTION ” CYLINDER RE-GRINDER It handles all engine cylinders from a motorcycle to a farm tractor. Regrinds a Ford Block of 4 cylinders in 134 to 2 hours; ora 10-in. x 35in. Mogul farm tractor cylinder in 4 hours. Thisis a new industry; and, in a little inexpensive shop with one lathe, and the PERFECTION attachment, you will soon have sick engines coming to you so fast that you'll have to work overtime; because Perfection Re- Grinding is precision work, accurate to one-half of one- thousandth of an inch—and, customers are so delighted that they send all their friends to you. And for every dollar you make in Re-Grinding, you will nen another dollar on the sale of oversize pistons and ngs. You belong in this business for yourself, instead of selling your skill by the hour to somebody else. Send for our circular and talk it over with Friend Wife. WOOD & SAFFORD MACHINE WORKS 57 Twelfth Ave, North Great Falls, Mont. THE MIDGET SLIDE RULE has many exclusive features. It will handle three factors at one setting and has a Log-Log Scale, Polyphase or Inverted Scale, Ad- dition _and_ Subtraction Scale, Square Root Scale, Log. Scale and Bi- 4\ nary Scale. Also gives Logarithms, | Sines, Tangents, Cosines, Cotangents !] and the decimal equivalents of frac- tions. This rule will add and subtract multiply and divide fractions and mixed numbers without changing them to de- : (wh Celluloid, $1.25 each, Genuine “Leather Carrying, Case, SOc extra. Circulars free. Your money back if you are not satisfied. GILSON SLIDE RULE CO. NILES, MICH. electrical,rope, air- ; plane, piano, pipe- organ, flat, hoops, bale-ties, tacks, nails, barbed-wire, concrete re-inforcev- ment, springs, _net~- ting, wire fences, steel ts, trolley-road wires and rail bonds, wire wheels, entetowing cables, horse-shoes. ‘ [ustrated Books Describing Uses, FREE American Steel & Wire Co.” *citico°*™ Pum Pilliod TOOL CASES EXCEL Machinists and Too! Makers find them most satisfactory in construction, appearance, service and price. Imme- diate shipment. Booklet describing 20 styles on request. The Pilliod Lumber Co. Dept. A, Swanton, Ohio then revolving this disk at a very slow speed for, say, twenty-four hours. During this time the particles tumble and keep working around through the manifold until the inside surface be- comes as smooth as the proverbial bald head. All the roughness and the small obstructions that impede the progress of the gas are thereby done away with. We havea better manifold by far and a motor with greater accelerating ability—a motor that will give you a maximum of speed and distance. It is surely worth trying. For the Small Car Owner I would like to see garages and Ford service stations adopt this method of helping the Ford owner for a small consideration and to the benefit of all concerned. It can be done if the garage or service station has any kind of stationary engine. Asmall gas engine, or electric motor, or even water power is not to be overlooked in performing the tumbling operation. First you must rig up the large wooden disk to which the manifolds are secured. The size of this disk varies according to the number of manifolds you may wish to tumble at one time, and as little as 14 horsepower is sufficient to revolve it at the neces- sary speed of.about thirty revolutions a minute. The manifolds, as you will noticefrom the illustration, are fastened to the disk by means of wooden cleats and one bolt per manifold, after the mix- ture of sand and broken glass or sharp pieces of iron or other metal have been placed therein. Only one bolt per manifold is necessary where an even number of manifolds are fastened to the disk to be tumbled at one time, as it is possible to bolt the carburetor openings of two manifolds together. By this means you also close these openings. The other two or upper openings are closed by -bolting this side against the disk, thus preventing the loss of any of the mixture during the operation. To Tumble Three Manifolds Where one wishes to tumble three manifolds at one time and where the shafting may have to go through the center of the disk, it is necessary to nail three projections of wood to the face of the disk, and then bolt the carburetor openings of the manifold to this projection, having the upper holes against the disk as mentioned above, and held against it by. the wooden cleat and a long bolt. The above, of course, is simply a ba- sis to work on, but it contains all the necessary data for improving the in- take manifold by tumbling. You know better than anyone else the material and power you have handy and can undoubtedly improve on the above method in some of its minor details. If your stationary engine or other 125 MOSSBERG ALL STEEL WRENCHES AND TOOLS "Universal recognition in those princi- ples of manufacture which insure to the user of Mossberg products the utmost in value and in service.. Such has been the standard of material, workmanship and guarantee, and such has been the appreciation of a multi- tude of satisfied customers. ILLUSTRATED HERE ARE: Mossberg Socket Set, No. 17, for Ford Cars. No. 74, Adjustable Wrench; also solid we wrenches 6 and 12 inch, with Speed No. 645 Reverse and Brake Pedal by sion Spring Wrench, and No. Wheel Puller. Mossberg All Steel Socket Wrench Set. No. 45, which contains an assortment of 15 sockets, universal joint and speed brace. Send for complete catalogue and particulars. tw TORK.USA FRANK MOSSBERG. CO, WRENCHSMITHS FOR 20 YEARS ATTLEBORO, . MASS. U.S.A.

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Carrying on the Inventor’s Aim When the inventor or en- gineer has done all he can to increase machine-output by mechanical means, a eeder Counter supplies further means. A Veeder records the output of your machine so you can de- velop the highest production- rate that efficient operation makes possible. In fact, you increase produc- tion with COUNTERS just as effectually as it would be increased by a higher degree of mechanical perfection than is yet attainable in your machine. Tak f isomer | _ This Set-Back Rotary Ratchet Counter records the output of punch chen metal-stamping machines and the ike, where an oscillating movement indicates an operation. Registers one for each throw of the lever, and sets back to zero by turning knob. Supplied with from four to ten figure- wheels, as required. Price, with four figure- wheels (as illustrated) $10 (list). Equipped with lock and keys to prevent tampering with the record, $1.50 extra. The small Revolution Counter be- low registers one for a revolution of a shaft, recording a machine operation. Though small, this counter is very dur- able; its mechan- ism will stand a high rate of speed, making it espe- cially suitable to many types of small machines, and most adapt- able for experimental work. Will subtract if run backward. Price, $1.75. There is a Veeder Counter for every purpose you may have in mind. Let us send you the Veeder booklet . The Veeder Mfg. Co. 44 Sargeant St., Hartford, Conn. source of power moves or revolves at a speed of, say, 600 revolutions per minute it will be necessary to reduce the speed by using large and small pulleys to effect a reduction in speed of the disk to about 30 revolu- tions per minute. For instance, a 3-in. pulley, turning at a speed of 600 R. P. M. revolves an 18-in. pulley at only 100 R. P. M., the driven or 18-in. pulley being six times as large as the driving pulley and therefore moving at only one-sixth the speed of the driving pulley. Suppose you now want a further reduction from 100 R. P. M. to 25 R. P.M. Simply place another 3-in. pulley on the same shaft as the 18-in. pulley and make this 3-in. pulley revolve a 12-in. pulley by means of suitable belting. The 12-in. pulley will revolve at the required 25 R. P. M. The same principle holds true in the use of spur gears as a means of transmitting or reducing the revolu- tions of a motor. Good on All Makes Do not make the mistake, however, that that which is good for the intake is likewise good for the exhaust mani- fold, as getting rid of the exhaust gases involves no engineering problem worth mentioning. It is, as remarked before, the intake manifold—the inhaling of the explosive mixture—that the pres- ent-day gas engineer principally con- cerns himself with. The two most important factors in the perfect mani- fold are the absence of too sharp corners or bends, and in the smooth- ness of its inside surface. While I have repeatedly mentioned the Ford manifold in connection with the above, it is equally true that the tumbling operation works wonders with any manifold, no matter on what make of gas engine it may be. It is not outside the realm of possibilities to infer that the time will come when all the intake manifolds will be smoothed during manufacture, or else some live service station will make a business of improving manifolds in this manner. . Modern Ways Nowadays there are many garages which find use for some motive power, generally to operate a small lathe or other machinery, and in instances of this kind the proprietor could easily in- stall the tumbling apparatus. A small air pump could. also be run from the same shafting as the other machinery. A tank would be filled with com- pressed air during the time that the other machinery in the garage was being used, and then from this tank the customers would be furnished free air. The proprietor would also be saved time and labor in connection with the vulcanizing and assembling of tires and tubes. By grouping apparatus in this way it would be not only possible, but' 126 Popular Science Monthly i lucrative, to furnish service to the owner of Ford and other cars in the matter of “tumbling” intake manifolds, To facilitate and expedite the sery- ice even more it would be possible for the garage owner to purchase a few second-hand or new intake manifolds, tumble them, and have them all ready to install, thus saving time and the possible laying up of the car. Again, there are many car owners who would be only too glad to have this smooth- ing and perfecting of the intake mani- fold done while the car is being over- hauled. A Brake for the Spinning Counter-Shaft N common machine-shop practice, counter-shafts and similar power transmitters are allowed to spin when’ the belt is thrown off for any reason, and many accidents have occurred from trying to stop them with a’bare hand. Asa conse- quence a ma- chinist devis- ed the follow- ing simple method by which such ac- cidents could be easily pre- vented and the spinning stopped when desired. A short sec- tion of canvas or leather belt- ing is suspend- ed over the countershaft pulley, so that the end hanging down touches the pulley on a side opposite to the direction of its rotation. A suitable handle is attached to its lower end. A slight pull on the belting will stop the spinning pulley in a few seconds with absolutely no danger.—L. B. ROBBINS. CANVAS BELT HaNOLE > Simply pull the handle and the shaft will stop An Old Hack-Saw Used as a Guide for Filing ORN-OUT or broken hack-saw blades should not be thrown away. They can be used for guides when filing articles to a straight and even line without danger of destroying the work by the file accidentally slipping past its desired point. Mark off the work at the re- quired point and place the hack saw blade against the piece of work so that it fol- lows the line evenly at both ends. Clamp work and blade into a vise, being very care- ful that the blade doesn’t slip. You can then proceed to file with- out-.any danger of going past the line.—THEODORE GATHMAN. BROKEN SAW BLADE LIMIT LINE FOR FILING WORK TO BE How the blade is attached to the vise

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' pew BS ae VEN ORF CO SS I |S wae OCO \w =v FOC Ce moran July, 1919 Things You Should Know about an Oil-Can HE illustrations offer three ideas ss hooey knowing about oil-cans. The first one shows how to adapt a short-spout oil-can to oiling places just out of ordinary reach. A piece of stiff wire is soldered along the spout so that the oil, pouring from the spout, will run along the wire on to the part being oiled. ; oe The. second idea is the application of a washer to the oil spout to prevent WASHER SOLDER SOLDERED ON wiRE TO SPOUT i] As usual, it’s the little things that count, and help you to economize it jamming. The washer prevents the spout from entering too deeply into the oil hole. The third is a method of reviving the tension of the spring at the bottom of an oil-can. A round-topped stick is held in the vise and the oil-can in- verted upon it asshown. While press- ing down, revolve the can. This will force the bottom upwards, thus giving it new life-—CHARLES H. WILLEY. Squaring a Board without a Square T sometimes happens that you want to square up the end of a board but haven’t a square with which to do it. In a case like this you can lay off a square end in the following manner. Make a mark along the exact center of one end of the board as shown in the sketch. Then lay one end of a - tuler or yardstick upon the mark and LINE IN CENTER ms yo LINE SQUARED Squaring without a square is simple if you keep this idea in your mind touch the other end of the ruler to one edge of the board, making a mark at that point. Then swing the end of the ruler across to the other edge and make a similar mark there. Connect these two marks with a straight line and the board can then be cut directly upon this line and will be found exactly square when sawed.—L. B. ROBRINS. have gaged the accuracy of the world’s work for thirty-nine years. Manufacturers, toolmakers, machinists and mechanics in all trades, rely upon this precision. Illustrated catalog No. 21W sent free upon request. The L. S. STARRETT CO. The World’s Greatest Toolmakers Manufacturers of Hack Saws Unexcelled SPECIAL KON-VER-TER SLIDE RULE— The Hamilton improved circular slide rule has over 8000 graduations and over 1800 figures and letters on it, and is an engineers hand book and slide rule combined. It is §.4 inches in diameter. \ It will subtract, divide, multiply, and add Mil] fractions or decimals of an inch, can be used as a decimal equivalents table, con- structed of three disks and double trans. #7 parent celluloid rider. Decimal equivalents given to six p'aces in figures, gives sines, co- sines, tangents, co-tangents, secants, co- secants, versed sines, co-versed sines, square, cube and fifth roots with all their powers, finds the area, circumference and diameter of circles directly. The Log. scale has 1000 graduations. The DE LUXE rule may be bent double without injury, try this with rigid material such as metal. Has no clumsy operating attach- \ ments and will work proportions. ) The KON-VER-TER is artistic as well as } uspfu IN use all over the U. 8., Canada, i Mexico, Cuba, Porto Rico, Panama, Bermuda, f Hawaii, Phillippines, Australia, New Zea- #/ land. Instructions with rule. Beautiful gold embossed black leatherette case [0c extra. PLAIN Utility Rules $1.00. SPECIAL DE LUXE. white ivory celluloid $2.50. PPD. J.C. HAMILTON & CO. Dept. A 7-Water St. Boston, U. 5. A. GENUINE Armstrong Stocks and Dies tL Lee HINGED PIPE VISES PIPE CUTTERS PIPE AND BOLT DIES MANUFACTURED BY THE ARMSTRONG MFG. CO. 337 Knowlton Street - Bridgeport, Conn. DUNN COUNTERBALANCES cforiitistts are the greatest y yet produced. Attached by remov- ing bottom plate from crankcase,—slip right into place and the four bolts are tightened with socket wrench. No machine work necessary. Installed in an hour. Can’t slip or work loose. Thousands in satisfactory use. Fifteen high priced cars have adopted counterbalanced crankshafts. Dunn Counterbalances produce same results in the Ford. Save 20% Gasoline, reduce Friction and Vibration to minimum, increase speed 5 to 15 M.P.H. and double the life of the motor. MAKE the Ford a SUPER-FOUR. POSITIVELY GUARANTEED, Beles ttt 20, Sarepene if Dat, entietth onder or O..0. Ds, Yauedt: aid. /AS| . . . “ ate shipments. ORDER TODAY. We sell all kinds of FORD SPEED SPECIALTIES, Write us. DUNN COUNTERBALANCE CO., Box S. Clarinda, lowa 127 USE HB BALL BEARING | ELECTRIC MOTORS | They Save Power—Increase Shop Efficiency ale ses tr Practically Unlimited B ; searing Motors furnish ideal power for garage, ma- grinjers, alr compressoc, cts,” ‘Beosomieah shea le eeebhs proof, amply designed to meet every requirement. Sizes 1 to 15 h.p. ake big power saving, require practically no atten- tion. Easy to install and Operate. $20.00 any HB Ball-Bearing Motor in Your =. Choose the Size you Balance on easy monthly terms. If in doubt about requirements, let our en- gineering d ent advise you. State what machinery you wish to run of current available. Pin d and mail a Charging Sets . ete. HOBART BROTHERS COMPANY Box $72 Troy, 0 Successful Manufacturers Since 1893

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‘Popular Science Me sis 74 : i AS SURE AS SOLDER HE easiest and quickest way to repair leaks in radiators, pumps, water jackets, motor head gaskets, hose connections, etc. is with Johnson’s Radiator | Cement. It will stop leaks immediately without laying up thecar. Johnson's © Radiator Cement is not a makeshift—it will give permanent satisfaction. 'No Experience Required — Quick—Efficient—Harmless .It requires no experience to use Johnson’s Johnson’s Radiator Cement blends perfectly ; Radiator Cement—all you have to do is re- with the water until it reaches the leaks— | move the radiator cap and pour the liquid into just as soon as it comes in contact with the 7 the radiator. It will ordinarily seal a leak in air it forms a hard, tough, pressure-resisting 4 from two to ten minutes. No tool kitiscomplete substance which is insoluble in water and | without a can of this wonderful preparation. consequently makes a permanent seal. A half-pint of Johnson’s Radiator Cement is ; : sufficient for a Ford or other small radiator. | Johnson’s Radiator Cement contains nothing For medium size cooling systems use a pint which can clog or coat the cooling system and and for large cooling systems, a quart. is absolutely harmless in every respect. Insist upon your dealer supplying you with Johnson’s Radiator Cement. Do not accept @ substitute. Write for our booklet on Keeping Cars Young--it’s free. S. C. JOHNSON & SON, Dept. P.S. M.7, Racine, Wisconsin OHNSON’S RADIATOR(EMENT |