Popular Science Monthly 1919-05: Vol 94 Iss 5

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20 Cents Off for Furope dati ——s ‘ie “ag . . e June Issue Will Be on Sale ‘Everywhere J une ‘Ist |

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a nited States Cycle Tires are Good Tires Ride a Bicycle WIFTER than the trolley car. Choose your own route. Take the Main Street or the path through the Park. Get out on country roads when you like. Every boy and young man should have a bicycle to make him independent of crowded trains and trolleys. It is better for health, better for promptness, better for efficiency in school, office or factory. A good bicycle should have good tires—United States Tires. You can always depend on United States. They are made by the world’s largest rubber manufacturer, in the longest-established tire factories in America. Every tire is made to uphold a reputation for quality. There are numerous styles of United States Tires either clincher or single tube. Any United States dealer will help you select the right tire for your wheel—the main point is— Be sure it is United States. 4

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Popular Science Monthly - Waldemar an i Editor Published in New York City at 225 West Thirty-ninth Street May, 1919; Vol. 94, No. 5 Twenty Cents; Two Dollars a Year — How Gold Can Make Us Poor , Ky ., Giant dredges for placer-mining may make the dollar. shrink NHE more gold there is in the country the oe : ; oorer we all are. Does this sound start- P , The man in the linen duster, Pp standing on one of the dredging ; ling and unreasonable? It may be start- buckets, is Mr. N. Cleaveland, ling, but let us see if it is unreasonable. ’ who built the giant dredge; Gold is the standard, the- yard-stick, by which and the other man is W. P. b. ‘Seman, dinate cotipaline the value of things in the United States—and-in all countries that have adopted the gold standard—is measured. By it the monetary value, or. purchasing power of the dollar, is measured. . It_is easy.to understand, then, that anything that lowers the intrinsic value of the standard—that shortens the yard-stick—diminishes the value and therefore the purchasing power of money; and it is also easy to see that, just as apples are less valuable when there is an over-supply in the market, so gold is less valuable at times when the quantity produced is greatly increased. Now, gold is mined in many parts of the United States, and the quantity of it available for coinage and other purposes is growing steadily.. A certain quantity of the precious metal is normally absorbed in the arts and industries without causing a marked disturbance of our monetary system, which expands in harmony with thecountry’s steadily grow- ing wealth. But supposing ~ that a new and prolific source of the yellow metal is found, or that some method is invented which will make it possible to extract the gold from its ores or from placer deposits easier and at less expense: the supply of gold may suddenly increase so that it will exceed. the normal demand. The immediate effect would be a depre- ciation of-gold; and as all other monetary values. are measured by the value of

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proportion. But it is clear that a dol- lar which is worth less than one hun-. dred cents will buy less than a dollar of full value. Why You Pay More If today you pay from twenty-five to one hundred per cent more for your food, your clothing, and other commodities ‘than you had to pay ten or more years ago, the over-production of gold is one of the principal causes. Of course during the war other causes contributed to the higher cost of living; but the upward tendency of the prices of practically all commodities was strongly marked long before the war. In the years immediately preceding the war, improved methods of mining and the introduction of the cyanide process of extraction caused an in- crease in the production of the yellow metal, which led to its depreciation and the diminution of its purchasing power, hence to an increase in the cost of living. In 1880 the production of gold in the United States rep- resented a value of $36,000,000; in 1900 the output reached $79,171,000; and in 1918 $84,456,600. The value of the metal absorbed for coinage pur- poses, which in 1850 was $31,981,739, reaching $62,308,279 in 1880 and $99,272,943 in 1900, dropped to $10,014,000 in 1918. This sudden drop was due to the con- traction of our national coinage by reason of war conditions.’ The enor- mous surplus that thus remained in other than coined form emphasized the depreciation of the metal and helped to boost the cost of living. gold, their value would shrink in : This gigantic dredge.can dig from 12,000’to 15,000 cubic yards of earth and gravel a day, and extract. from it practically every.:bit.of gold it carries In the light of .these considerations, it bécomes evident that the invention ofa powerful dredge, which can dig up from 12,000 to 15,000 tons of gold- bearing alluvial deposits a day and extract practically every ounce of the yellow metal the gravel contains, can scarcely be expected to lower the high cost of living. Such an invention ‘makes it possible and profitable to work over gold-bearing deposits so poor in gold that they could not be worked with profit by any other method of mining. The dredge shown in the pictures was built by N. Cleave- land, and is in successful operation along the Yuba River, near Marysville, California. The dredge, together with the ma- chinery for driving it and the appa- ratus for extracting the gold from the soil, is carried by a barge 165 feet long, 68 feet wide, and 11) feet deep. The entire equipment weighs more than 2,000 tons. One hundred manganese steel buckets, each holding sixteen cubic feet of’ earth or gravel; are at- tached to an endless chain which runs over rollers at the top and bottom of Popular Science Monthly the digging ladder, which is raised and lowered by means of suspension tackle, The buckets have sharp cutting edges and can aig to a depth of 80 feet under water. The bucket chain is driven by- electric motors. The dredge ig kept at work day and night. It Stops Once a Week The earth and gravel dredged up by the buckets is dumped upon a revolv- ing screen at the upper end of the dig- ging ladder. The screen is made of perforated plates of high-carbon steel. It has a length of fifty feet and a di- ameter of nine feet. A powerful stream of water pumped by electricity washes the gravel and breaks up lumps. The gold is washed out by the water, and, together with other heavy matter in a fine state of division, passes through the screen and is washed into an ad- justable distributor, which deposits the gold and other heavy materials on | inclined tables indented’ by shallow grooves filled with mercury. As the gold is washed down it comes in con- tact with the mercury, forming an’ amalgam, which is re- After the:gold-bearing gravel and earth has been thoroughly sifted and washed and. relieved .of the. precious burden of gold, the tailings are dumped in piles by conveyors 20 moved from time to time . to extract from it the gold. The gravel tail- ings are carried off by conveyor belts. Once every week all dredging operations stop. The gold-mercury amal- gam _ is collected, and fresh mercury is poured into the channels of the amalgamation tables.. The amalgam is pressed into the form of bricks and sent to the distilling works. There the mer- cury is recovered to be used again, and the gold is molded into bricks and refined. The cost of oper- ating one of these dredg- ing equipments is about five cents a cubic yard.

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sed and. . tackle, ig edges +t under driven edge is k d up by revolvy- the dig- nade of yn steel. nd a di- | stream ’ washes os. The ter, and, tter in a through ) an ad- osits the rials on — shallow As the 3 in con- ning an’ 1 is re- e to time . it the vel tail- | off by veek all ons stop. distilling’ che mer- od to be the gold ricks and tof oper- — se dredg- is about ‘ic yard. ) facie Across the English Channel by _..- Air in Three Hours > RAVELING from London to Paris ; a Goliath, the by airplane is-no: longer the ex- ences passenger- elusive right of airmen and celebrities. Pigg be Anybody with eighty dollars in his er Caudron ‘aabioes ‘pocket can now make the trip; for give ita speed of eighty dollars is the fare charged by eighty miles an hour the Farman oneapiie: ‘théir’ new pera aris-London air line. . ginally designed | aihiiz nei machine, named the Goliath, is “ pan Berlin, | SO already in use, and five more of the been refitted for are- alt, same model are in course of construc-_ gular passenger ser- GUNES tion. .You start from the Buc Aero- -. Vice between Paris drome near Paris, and you can land at Croydon, England, three hours later. If you want to take baggage with you, you may do so. The Goliath was originally built for bombing Berlin, but the armistice cut short its career, and it has since been transformed for commercial use. It makes an admirable passen- ger-carrying aero-car. Its long fuselage cabin affords seating space for fourteen persons in springy leather arm-chairs with wicker backs. The chairs are placed singly, one behind the other, from end toend. Twenty passengers may be carried, but the number has been limited powerful enough to continue the flight. The machine has to fourteen for comfort. Equipped with two 270-horsepower Caudron engines, the For the person of fastidious taste who desires quicker Goliath can maintain a speed of from~seventy to eighty service in a car of luxurious appointment, the Farmans have miles an hour, which is fast enough for commercial purposes. a veritable limousine of the air, equipped with a salon cabin I The employment of two engines practically eliminates the containing tables, arm-chairs, and a lavatory. Three or risk of accident; for if one engine goes ‘“‘dead’”’ the other is four passengers may be accommodated. How to Keep the Flag of Freedom Free Using the Telephone | DEVICE has been in- vented making it cer- tain that “the star-spangled banner in triumph shall wave’’ and not get all tangled up when displayed on a_ hori- zontal staff. A wire rod extends along part of the edge of the flag, and is held in place by a clip at each end. The larger sizes may have a hook to pass through one of the eyelets in the flag. This, in addition to the clips, insures stability in heavy winds and storms. The invention prevents the flag from being whipped, wrapped, or tangled, and is a protection against tearing or other injury. The lower clip can be of heavy construc- tion so as to hold down that part of the flag. In attach- Ing it, the hook is first passed through the eyelet and then the edge of the flag is forced Into the clips. By increasing - the number of turns in the lower clip it can be made as heavy as desired. and London a wing breadth of nearly one hundred and fifty feet. to Test an Armature ) -~[.N order to discover a short | circuit, open circuit, cross- connection, or ground, it is necessary to have a set of test leads and lamp, prefer- ably on a 110-volt line. Tie a string around the com- mutator, and place both sides of the test leads under the string, against the segments, about one fourth of the cir- cumference apart. Next hold the receiver to the ear with one hand and receiver leads to commutator with the other, taking care to touch adjacent segments, and, traveling from one test lead to the other, move test leads farther around, repeating until the commutator has been circled. s A low buzz in the receiver Ain indicates a good flow of elee- tricity. If you get no sound whatever there is a dead short circuit. An open circuit is indicated by a very loud This non-tangling device for flags is a wire rod having coiled clips at each end buzz. 21

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Popular Science Monthly: When Thirst and the Law Clash Moonshine-makers haunt New Y ork cellars as well as Kentucky mountain caves 4 ~ The home-niade * still , - ' ne shown below was found, ' * A & AEShew yee not in a mountain cave, a Ee but in a New York-city - ie . flat. Revenue men:say ; that cities are. ‘their best hunting ground This old man is said to be the most ancient o! moon- shiners. He was born 102 years ago in the Ken- tucky mountain cabin be- hind him. Perhaps he.did not drink his own whisky © Kadel & Herbert With the family For movie purposes this wash-boiler and a is the only kind of a little ingenuity one site for making moon- can make a very shine whisky. The folks useful still. This there don’t care if the one was found ina country does go dry : NewYork city cellar Flanked by the raiders whose business it is to help Even the Eighteenth Amendment can’t move stills of prohibition prohibit, we see the remains of a still. The this size to big cities, no matter how great the demand snakelike coil is technically known as the “‘worm’’; in for cases in the desert. The raiders found this one in it the vapors condense and start the red-eye flowing the Southern mountains, where the best stills live

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Next time someone tells you of its raining fish or frogs, don’t laugh: . the - story .is probably: true.: There is, for instance, record of a fish rain in 1666 that showered smelts all over Stanstead par- ish in merry England ee eee = - : oe ‘y BAY At Baton Rouge in 1896 it rained ducks, catbirds, m\ . od f Mi pa ba” oe rs ee and woodpeckers. We pause right here to say that scientists explain these showers by the lifting power of the wind and the ancient principle that what goes up must come down; and younever can be sure what’s up Getting down to 1917, John Lewis, of Aber- dare, Wales, reports: “Iz was startled by something falling all overme.:.. . . On putting my hand down my neck, I was Ee surprised to find : eee ; they were little fish” = Singapore, as might : be expected, holds : the shower record, with a rain of fifteen- inch catfish, which the Chinese and Malays gathered up by the basketful Boston, in the days of the “plug” hat, had what it called (being Boston) ‘a pis- catorial deluge.” But in Connecticut that same year it rained fish and ice togeth- er, which we call thoughtful No less a person than Alexander von Hum- boldt writes of a downpour of fishes in the Andes which seemed to be aided and abetted a very active volcano. The natives said they rather counted on fish showers to reduce H. C. L., usually having several a season Nine native eye-witnesses, urged by a canny Scot, made depositions before a magistrate attesting the truth of their tales of a shower in Bengal during which at least five kinds of fish fell from the heavens e

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Popular Science Months Making the Dumb to Speak The latest methods of specialists in treating victims of shell shock of.the serious results that devel- oped in niany soldiers suffering from shell shock. It afflicted most frequently men whom the hor- rors of the Great War had brought to a state of nervous tension which predisposed them to this particular pathological condition. Drs. G. Liebaut and” E. Coissard, two eminent French nerve specialists, studied the disease, and organized a clinic for restoring to these soldiers the power of speech in ac- cordance with the -methods employed in schools for the treatment of deaf-mutes. Among the patients in that clinic there are none who have lost their ability to speak through any physical injury of the organs of speech. Nearly Cr eee sort loss of speech was one By Lucien Fournier inhalation and exhalation by a stop- watch. Then the functioning of the larynx, lips, and other speech organs is carefully observed and noted. To restore the normal functions of the vocal cords is far more difficult, After the patient has been taught to breathe properly, his throat is m by hand or by an electrical vibra. tor. By slow degrees the shell. CONSONNES _VOYELLES eats WANES GRESSIVES cRESSIVES! Gg pip? BUCCALES Seen js Wb AN See 3 Bee ELEMENTS AMORCEURS pap oe. NASALES! DE LA VOIXe SOUFFLE VOIX. CH J shock victim is taught to emit sound at the time of exhaling, First the Vowels The patient begins with the vowel o. If he does not succeed in emitting the simple sound, his throat is gently manipu. lated by the doctor, who de presses the larynx of the patient with his fingers to stimulate and assist that organ in the effort of resumingits normal functions, These. exercises can be taken for only a brief time each day, After the patient has leagned all of those who undergo treat- ment are eventually cured.or at least greatly improved by a The doctors give individual attention to each case, a detail of the treatment being massage of the throat by hand or by an electric vibrator to pronounce the vowel o with- out assistance, he begins to systematic training of the organg of speech, which include the lungs, the larynx, the pharynx, the mouth, nose, and lips. Careful Examination of Each Patient Before beginning treatment the doc- tors carefully examine each patient to ascertain his lung capacity, method of breathing, and any abnormal pecu- liarities in the mechanism of drawing in and expelling air. The lung is measured by a simple yet accu- rate apparatus devised by Dr. Coissard. The apparatus is con- structed like a gasometer. A cylindrical tank is filled with water. Within that tank, but cloved at the top, is a smaller cylindrical con- tainer, held in position by coun- ter-weights connected with it by cords running over pulleys. The air exhaled by the patient is conducted by a tube into the floating cylinder, and, by displac- ing the water contained in it, causes the inverted container to rise. A scale on the side of the tank indicates the volume of air Each case is studied individually by the doctors. After a thorough consideration of the facts in each case, the method of treatment best suited to the condition of the patient is determined. Breathing exercises are given first, to correct any defects developed by the nervous affection of the patients in their respiration. These exercises are supported by gymnastics of the arms and body. learn how to pronounce the vowel e, which in French is pronounced like “ay” in the English word “bay.” Then follow | in the same order the vowel sounds eu, ou, u, a, and 7 as pronounced in French. ; The last phase of the treatment includes the careful’ and systematie training of the muscles of the cheeks, tongue, lips, pharynx, and nose whieh present symptoms of paralysis. These exercises are performed by the patients in front of a mirror. After they have learned to respond in an almost exhaled. The chest expansion is measured with a tape-measure, © and the movements of the dia- phragm are recorded by two radio- graphs taken of the extreme posi- tions of elevation and depression during the process of breathing. The force of exhalation is measured by a pulsometer, and the time of ‘Faeing large mir- rors, classes of patients are learn- ing to pronounce the vowels a and i. After mastering the vowels the pa- tients begin on com- binations of vow- els and consonants normal manner, the patients essay the pronunciation of simple combinations of vow- els and consonants. — In most of these case speech is restored in a few months.

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ock nections of > difficult, taught to 3m rical vibra. ; the shell. ht to emit f exhaling, wels s with the 10t succeed ple sound, y manipu- r, who de the patient mulate and . the effort il functions, 1 be taken e each day, has leatned wel o with- | begins to nounce the in French y”’ in the ‘hen follow wel sounds pronounced 2 treatment systematic the cheeks, nose whieh ysis. These the patients ave learned . an almost _ the patients unciation of tions of vow: nants. | these case red in a few NE man must have been deeply touched by sad tales of rowboats a perro swamped in storms. He is Louis O. Anderson, and he has invented a ‘‘storm cov- er” for boats which, when adjusted, covers both boat and rower so completely that waves and rain will roll off duck’s The a head its junction with the rub- berized cover, so that the oarsman may try to paddle with one of his oars while sitting tail spread out behind him. His backbone for the cover. It rests woode coverup. The plates curve down toward the boat-edge so that water will roll off. The cover itself is fastened down complicated system of bars, hooks, eyelets, and lugs, which drop of water from enter- ing, and also makes ad- justments too difficult for use W necessary. We are somewhat puzzled as to into his suit after he has adjusted the cover. Housed in a Boat-House first place, for light. . least, boat-owner who spends the winter _in Florida. ., The’ architectural lines of the structure are clear-cut and grace- ful. Curved eaves and a sloping _Toof. shed decay. it as water rolls off a back. suit which includes -piece is made full at in the stern with his other oar makes a in grooves in the n plates that hold the | to the boat by a prevents the smallest here quick action is how the rower gets » of Glass HY should a man want a glass boat-house? In the That, at seems to have swayed a make an excellent water- which will not, mildew or If necessary, the whole : building can be washed down with ,& hose from top to bottom with- -Out damage to any part. The ' p@lass is frosted, and softens the rays of the sun. oo £ at for Man and Boat Man and boat are enveloped in a big flowing cover 25 Keeping the Diver Down HEN a diver goes down one hundred feet or more he is pressed upon from every side by tons of water. The suit he wears is blown up with air not only for the purpose of enabling him to breathe but also for the pur- pose of offsetting that water-pressure. Otherwise he would be squeezed to a pulp. This air-pressure forces nitrogen into the diver’s blood. The nitrogen is not dissolved; it is held in the blood, like the gas in a bottle of beer or ginger ale. Pull the cork from a bottle of beer or ginger ale, and the gas bubbles up. That is exactly what happens to the diver’s blood if he is suddenly pulled up from a great depth. The nitrogen When the diver wants to be pulled up he removes the connec- tion containing the life-line, etc., and steps on the weight , Sac SS : SS OS, boils off. For safety’s sake he must ascend in very easy stages; the nitrogen must be allowed to escape very slowly, Hermann Stelzner in- vented the diving gear shown in the accompanying illustration. As a rule, the diver descends by what is called a “shot - rope” —a knotted rope at the bottom of which a weight is at- tached. Stelzner gives the shot-rope a new form. When the diver wants to come up, he simply stands on Stelzner’s weight and grasps the shot-rope. Of course, strong cur- rents will affect Stelzner’s diving gear, just as it- af- fects the type at present in use. But if you will study the accompanying drawing you will see that the pull is chiefly in a horizontal direction. In other words, the diver cannot be swept off his feet and carried up~ ward by reason of the buoy- ancy of his inflated dress. Should the diver be forced up to the surface, he can be quickly pulled down again without the present neces- sity of deflating his dress to make it less buoyant. Miami, Florida, has a neat boat-house made mostly of glass, with curved eaves and a sloping roof to shed the rain easily

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S you plunge your spoon, at break- fast, into that luscious orange upon your plate, do you think about the care entailed and the long journey necessary for that particular orange before it is set in front of you in its present perfect condition? A Stethoscope for Engine Ills NE of the intricate problems that an automobile mechanic has to deal with’ is distinguishing the various kinds of knocks that an engine is subject to. To do this successfully a listening apparatus is nec- essary, and the one illustrated below is easy to make _and will serve just as well as the bought article. It is made of a 34-inch copper tube about 8 inches long with a steel point welded at one end. In the other end a steel rod is inserted, making a snug fit inside the copper tubing. A telephone receiver is then connected _ by a wire to the end of the steel rod. knocks, pull the steel rod out about four inches. Touch the suspected part of the engine (when it is in operation) with the steel point,-at the same time placing the telephone re- ceiver to the ear, and the knock will be distinctly heard. Loose connecting rods produce a sharp bump ora heavy hollow sound. Main bearings are readily located by running two cylinders of the engine at a time, one on each side of the crank bear- ing, producing a hard bump. A loose piston-pin gives out a sharp metallic knock. A loose fly-wheel will pro- duce a heavy knock at low engine speeds and appear regularly. A loose piston gives a short, sharp knock, and loose tappets will pro- duce a brisk tap. Oranges that ne" At the orange ranch the oranges are picked by experienced men, who sort them into various grades, pack them carefully into boxes, and place them upon motor-trucks that travel fifty or even a hundred miles to the nearest railroad. THERMOSTAT FROM TOP OF CYLINDERS sii It keeps the engine at its most economi- In locating the An easily made knock detector that will locate engine knocks be- fore they have a chance‘to develop into serious complications 26 otor to Their Train : Motor-trucks play an important part in orange transportation, since by their use a second handling at the ware house is entirely eliminated. cal temperature * Sorted in the or- = St chard, the orange is hauled to the rail- way bymotor-truck, eliminating the usual second hand- lingatthewarehouse Keeping the Chills from Your Engine HIS’ thermostat is mounted in the top of a cross-shaped pipe, connected with a main valve in the horizontal part of the pipe, and this in turn with a by-pass valve in the lower part of the pipe. : When the water in the cylinder-jacket reaches @ temperature of 170° F. the diaphragm of the ther- mostat expands and opens the main valve, so that the water circulates through the radiator as usual. The by-pass valve is then closed. As soon as the water drops below 170° the thermostat diaphragm contracts, clos- ing the main valve and opening the by-pass valve.

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the or- orange is the rail- or-truck, ig the nd hand- arehouse ant part by their e Wware- Chills ungine stat is the top d pipe, a main ntal part this in iss valve t of the. r in the aches @ 170° F. the ther- nd opens — . that the through ial. The en closed. : ter drops — vermostat — cts, clos- alve and ass valve. | ) oa iste A Really Non-Leakable Gasoline Pet-Cock - is the small losses of fuel, the es little drops from a gasoline line, that, taken over the period of a year, amount to many gallons. . One of the sources of small leaks on a car is in the pet-cocks in the gasoline line. When these cocks be- come worn from continued turning, _there is often the slow drip, drip, drip, day and night, that finally affects the number of miles per gallon secured. ; . Troubles of this kind would be eliminated if every car were fitted with . the new type of non-leakable pet-cock shown in the picture below. There is no opening in the bottom of the cock, and consequently there can be no leak there. The stem of the plug is packed so that it cannot leak at the top. The packing is of woven asbestos, and it is held in place by a spring, which simultaneously presses down on the top shoulder of the tapered plug, so that it is at all times kept on its seat. PACKING UP AND PG DOWN NO OPENING AT BOTTOM A new type of non-leakable pet-cock which has no openings that leak and waste gasoline “ AND the entire axle was painted with one daub of the brush.” What? You find that a bit thick? But that is just what is being done in truck factories that turn out immense pro- duction. The work is done in a Special compartment con- | taining the painting ap- paratus. An up-to-date ’ feature of this compart- ment comprises two elec- tric fans designed to draw off the paint fumes and thus protect the operator from lead-poisoning. As may be seen in the photograph, compressed air is utilized to force the paint from the nozzle, the paint being led down from a reservoir, placed high on the wall of the You can stop a powerful car instantly, without its skidding, with this brake A One-Finger Emergency Automobile Brake PPLYING the brakes of an auto- mobile is almost as easy as pressing the key of a piano when the emergency brake of one of the new types of automobiles is used. The ease with which the ‘‘one- finger’”’ brake operates is due primarily to the fact that friction is applied al- most directly, without cumbersome devices. A short rod attached to the lever near the pivot on which it turns connects with a goose-neck, which operates.the mechanism that closes a clamp on the shaft through which power is transmitted to the rear wheels. Painting Trucks by Compressed Air y. S ray eS momemenns 67% In truck factories where production is based upon a big scale, all parts are now painted by compressed air in a special compartment 27 x) ' The.New Safety Cut-Out _. fer Ford Cars - “NEW. type of safety cut-out, « J: \-which> cant be fitted on any type Hof Ford muffler, deflects the exhaust | gases downward instead of. permitting them to shoot out horizontally and ‘damage the spare tire. » “It consists.of a‘cover for the rear of ‘the muffler. This cover has a circular operiing at the*center of the end and another opening: at the bottom. The center opening is ordinarily closed by ‘-a cap operated from the floor of the cab. » Under ordinary running the exhaust --gases are deflected*downward out of the muffler through the bottom open- ing. When it is desired to use the -muffler cut-out, the cap is simply open- > ed by operating the foot-pedal and the ‘gas is forced out horizontally. {TO CAR he FLOOR-BOARD SPRING CAP MUFFLER A new Ford cut-out which deflects the exhaust gases down instead of horizontally compartment, through a heavy rubber hose to the air nozzle held in leash by the operator. After the crane has hoisted the axle to the desired position for paint- ing, the operator, merely by a slight pressure of his thumbs, allows the paint to envelop the axle in a fine, thick spray which reaches every nook and corner. After the axle has been covered thoroughly with paint it is taken to the ovens to be baked. Where production as- sumes gigantic propor- tions, the value of a paint- ing compartment like the one illustrated is easily realized, for it promotes economy as well as pro- ducing an efficient job.

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Down at the bar rail, where worth- less) men throw at it worthless things. It has fallen so low that it is just one step above the~euspidor Tony’s brother brought home two helmets. He gave one of them to Tony and the other to‘ their mother. Now, Tony is a cobbler. and uses many nails. He turned his helmet upside down and made a tray. to fit‘ it.° In the - tray he keeps small nails, in the helmet large ones Photographs © Kadel & Herbert Popular Science M : | Making Over Last Years Hun Helmets Their material and shape will make them useful in places high and low Up in the tree-tops it serves as a‘bird’s nest de.luxe. Yet the poor- est little early bird can move in_ rent-free and raise her family Tony’s mother is indus- trious and neat—note the lace edging on the shelf over the stove. She is also economical, and so, instead of hanging her helmet over the parlor mantel, she has brought it * into the kitchen, ‘and boils in it the family potatoes The flowers that bloom in the spring have nothing to do with the pot. These are flourishing in a most unattractive old thing—a German helmet. These helmets. are very useful, they balance so beautifully

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When There’s Sickness If an elephant insists on having his toe-nails pedi- cured, his valet will have to use.a saw: that’s about the only tool that will sink in Ss bad case of par- alysis of the trunk. The doctor never knew that ele- phants’ trunks would: paralyze, so he rather doubt- fully. bandaged it. He _ is waiting for signs of life in the: Circus In the best of health now, but apt to play sick as soon as he sees some other monkey getting at- tention. Monkeys have as many -real and imaginary. ail- ments as do some of the “‘idle rich” The worst of dosing a camel with médi- cine is-that he may either: use it or tuck . it away-in his pouch for future reference, thereby’ either’ get- ting well or sicker e He looks \V sick, and he is—just doesn’t care He’s a wildcat, and he’s not going to let any sore paw what hap- '.j pens to him; can’t feel any worse tame him down; rather, does it make him wilder. He insidethebag than out of it; might as well get in would joyfully bite and scratch the hand that dresses him

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Piloting a Steamer with a Trolley Line < Should this plan be found practicable there =: would be no more collisions in foggy weather of an incoming ship in a fog? Did you notice-how anxious the captain was? Did-you watch a man time and time again heaving the lead? Do - you remember how care- fully the ship felt her way? She was in dangerous water, and her navigators fully realized it. -It.is not the fog alone that is feared. Fog not only prevents the look- out from seeing, but it distorts sound as well. You hear the blast of a “siren” or the ringing of bells, but you cannot safely judge of their dis- tance. Sometimes the sound is lost altogether. Fog-horns mark danger- ous points, and a navi- gator must guess not only where that fog-horn is, but just how far he has to keep away from it. So with ships. Often I have heard a warning whistle, and im- agined a ship well to port or star- board some distance off, only to have my hair raised a moment later by seeing a great black hull looming up perilously near and on the other side. Perils of New York Harbor A few weeks ago I spent three hours getting from Sandy Hook to Tompkins- ville, in New York harbor, and that with one of the best pilots thereabouts. We merely crept along, for we knew He: you ever stood on the deck instead If the day comes when vessels pick up a trolley instead of a pilot, one more pic- turesque feature of ocean life will be lost to those who go down fo the sea in ships By. Fe W: Fitzpatrick that three vebacls must:be near—knew it without. doubt. by. the number of distinctive whistles that we heard. Off Fort Hamilton the fog lifted for

The amount of line to be paid out will indicate the depth of the channel the pilot is in, and so he will direct from the stern of from the bridge, the pilot’s usual vantage-point a few minutes. There were thirty- four vessels in sight, five very close to us. Almost across our bow was anchored a bell-ringing sloop of whose presence we knew nothing. Three big liners had wisely anchored; they had been there, I was told, for more than seven hours. All this means an enormous waste of time. The cost of such delay must amount to hundreds of dollars a day in the case of a large ship, not to speak of the terrible risk to which every

Popular Science Mon , vessel and its crew are exposed. The- inventors have tried to help out the shipowner and the shipmaster with their contrivances. Here are some of the ideas that have been suggested: lighted - buoys, finders of various even an electric tr \ \ \ \ N N NN N SY \ tracks. Most of thege inventions are impracti- cable; actually obstruct naviga- tion in fair as well as in foul weather. What My Suggestion Is Let me now offer a sug- gestion of my own. I have not patented the device, even know whether it is patentable. the public. YU: gested my invention. I would lay a heavy wire cable from some con-: venient point in a harbor to a point at the mouth of the harbor where there is deep water and sea room. safe distance from the other course, 4 half mile or so, to the point of de parture, and there splice the ends. We would have a continuous cable, a loop, anchored at suitable distances, 80 that it could not be torn away and be- come a source of danger. The light-ships, one at either end, mark deep water. and I do. not’ I offer it to The trolley car siig- This cable I would continue back, at a The line that [I

.. Continuous _ lines ~ of. : 2 electric. indicators, and channel. system and under-water some would -

ha’ chi po otl pre str ine lig! ( spe an bu the or cie C01 de} in the lig] the shc

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ion Is have described would be that of the channel. a stige The light-ship at the sea end of the wn. I cable would be equipped with the most 1d the powerful fog-horns, bells, guns, or o not” other noise-producers that scientists or it aot prescribe for use in a fog. These in- er it to struments would not be a warning of aM danger, but a call to safety. Every r sig. * incoming vessel would steer for the ion. light-ship. y wire On this cable would be a number of e con specially devised rings to which other oint at and lighter lines would be attached. e there These lines, or trolleys, would be This buoyed at a length to insure floating in , at a maximum water—125 feet orso. Thus vurse, & they could be picked up in case of loss of. de or breakage. There would be a suffi- e ends.’ cient length of cable or trolley line tc sable, a cover the angle of drag and varying nces, 80 depths, and for handling slack, etc.— and be in all, say six hundred or perhaps <i seven hundred feet of line. All of er end, these lines, by a sufficient number of that I rings, would be held on this “safety” light-ship, and a similar number of them on a tug or other boat at the shore end of the loop. Necessary Harbor Regulations In foggy or thick weather, or for that matter at all times, a harbor regula- ‘ tion would prohibit all sailing-craft = from entering or anchoring inside of this sixty-foot depth, unless in tow of a tug or steamer. Another regulation sith would compel every tug, boat, and m steamer to steer directly to this light- a ship and there receive one of the “ trolleys. In calm weather it could be handed over by a lighter “casting = line,” such-as is used in handling x heavy landing or tow lines, and in Tough weather it might be shot across & vessel’s bow. But there is rarely a \

Every vessel would steer directly to the light-ship and there take on astern one of the trolleys; the vessel would then proceed under her own steam, dragging her trolley along the main cable sea on in a fog.- A heavy sea means wind, and wind means no fog. In my plan for piloting ships, the trolley is taken on astern. The vessel then proceeds:‘under her own'steam at a safe rate, dragging her trolley along the main cable. As long~as the pull is fair astern the ship is on the right course. BF! n ; Naturally, the master will have to allow for drift, currents, and the angle of descent his trolley line indicates, but the procedure will be a thousand times safer and easier than constant sounding and the guessing he has to do now. He has the assurance of being safe. No one can run into him side- ways. He will have to watch so that he does not run into the vessel ahead of

JERSEY NY, SHIP CABLE Y

¥, GOVERNORS IS.

SHIP *s, @ 3 -.. CABLE "ASR a, LIGHT oy SHIP See!

$89) sa (gee warps’ 29 hee te CONCRETE ANCHOR

The author’s plan is to lay a heavy wire cable from some convenient point in the harbor to a point near its mouth 31

him, and to make noise enough to insure that the ship following him will not collide with him astern. It is the same as navigating a cable car, minus the inherent dangers of the cable and the passing of teams and people; The Pilot at the Stern The amount of line paid out indi- cates the depth of the channel the pilot is in, and tells him positively where he is. In other words, the pilot directs from the stern instead of from the bridge! Each vessel should have an auto- matic steam-drum adjusted to the drag or pull of the ring along the main cable, so as virtually to lift the cable a trifle, but not enough to drag it or raise it more than to allow the passing of the ring under its under surface. By means of adjustment the angle will be maintained, the cable being paid out or in according to the varying depth, but steam being shut off at the maximum depth and the slack line being paid out loosely until the vessel is stopped and the trouble investigated. If the line is made fast.to the vessel, any catch or accident’ means the breaking of the trolley line or damage to the main cable or its anchors. Such a machine would make it possible to handle a 14,000-horsepower vessel as easily as the smallest yacht. All incoming vessels would follow the right cable and deliver over their trolleys to the tug or other boat charged with the mission of receiving them at the shore end of the loop. Outgoing vessels would receive these trolleys from the tug, and follow their trolleys to the light-ship at its outer end—a system of double-track street- cars, pure and simple.

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Working on a deaf man. The man places his forehead on the’ — lid and his hands .on.-the sides-of the instrument, while the pianist - plays major chords very loudly recognized curative value? That different emotions are excited by different sorts of musical strains has been appreciated since first Pan played his reeds. The easy cadence of waltz time in- vited our fathers and mothers to dance, just as the sound of the so- called ‘‘jazz’’ prompts the -pres- ent generation to step and glide or slide about. The snap of military march time quick- ens the pulse. The soft crooning of some Southern mammy lulls to sleep a tired, fret- ful pickaninny. Miss Anderton's Theory Miss Margaret Anderton, a. con- cert. pianist, and the originator of what. she - terms the piano causerie, which consists of prefacing each program number with a few cleverly chosen words with the idea of creating a better understanding of the numbers played, has studied the sedative and, in what she believes to be an astonishing number of cases, the curative properties: of musical sound vibrations. Miss Anderton had been making an analytical study of the effects of musical sound vibrations for some time when the war came. She was in Canada at the time, and she became strongly impressed with the belief that she could make use of her ideas in helping soldiers who were wounded or victims of shell shock. Perhaps her own words describe the work best. She says: “The concert artist should use her skill for the scientific application of H music a new and hitherto little ~ Can Music Cure as Well as Charm? How a concert pianist turned her music to the business of healing By W. music as a medicine under a doctor’s prescription, a different matter from simply playing music to soothe or divert. “It is high time that art became altruistic. Musico-therapeutics should not be a commercial asset. The artist, giving of her highly trained abilities to the service of science and the medical profession after years of private research work, feels profoundly T. Perry therefore, is curative. It is not an entertainment. It is not to play to. invalided soldiers just to pass the time away, merely to amuse and pleage them. Music is to be administered with a definite, scientific p and only after careful study of the medical reports of each individugl case and of the patient’s physical history. Different sound vibrations produced by different music. al instruments, Teaching a man suffering from shell shock to play the xylophone. At first he is almost afraid to strike the instrument, but, grad- ually becoming more and more confident, recovers his mental poise the use of music as a curative means. The procedure is psychological.” The purpose of musico-therapeutics, A man who had lost the use of three fingers was taught to play with two fingers; as a result the para- lyzed fingers became almost normal F , 32 different keys, and different time are selected for each individual case, Thus a man who had been a struc. tural carpenter, and who was 4 victim of shell shock, was pa tiently taught to play the xylo phone... At first he hesitated to: strike the bar even gently. Step by. step, he was persuaded lightly to tap the keys, and later. to pick out ‘‘God Save the King,”’ a tune he ~ remembered Soon he was ham- mering away lustily, and, it cidentally, re ‘covered his poise. Another inter esting case was that of a soldier who, after a high-powered shell had exploded near him, although he was untouched, believed himself deaf. Distinctly Not for Enjoyment This man could hear absolutely noth ing. After inducing him to place his forehead on the piano-top and to pres his hands against the sides of the instru ment while loud major chords weft played, his hearing became acute. As Miss Anderton points out, musi¢ so played is not supposed merely to he enjoyed in the way that normal, w folk enjoy music. It is rather that the tone vibrations, varying in quality, rhythm, and intensity, may, whel _ properly applied, alleviate and often cure neurotic conditions. = «9 Se) ee GA bet bets oe re" ©4 7

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} not an Play to. the time id please Linistered Purpose, | ly of the ndividual physical produced ent music- ruments, _ keys, and , time are for each al case, a man who nm a struc arpenter, nO was 4. of shell was pa taught to the = xylo At first sitated to: the bars” ntly. Step p, he was led lightly the keys, ter to pitk | od Save the a tune he mbered. e was ham- ng away , and, it- tally, re d his poise. her inter g case Was of a soldier d shell had ugh he wai lf deaf. joyment olutely noth- to place his and to pres of the instru chords were e acute. ts out, m merely to he normal, ; rather that ng in quality, may, when fe and often “cost is often. made up: by If You Must Smoke While Wearing Your Influenza Mask : T js all very well to use an influenza mask. But what if you want to smoke? Edward T. Duncan has supplied er. wees buy two corn-plasters at a drug store. You may not see the relationship between a corn-plaster and the influenza. Wait a minute. Hasn’t the plaster an opening foracorn? Well, that hole can be made to fit a cigar or a cigarette. Paste one of the plasters on the inside of the mask and the other on the outside, as shown in the picture. Extend the hole of the outside one clear through the mask. The other plaster is put on merely for beauty; it provides symmetry. % . ‘ When you draw on your cigarette, all the little germs hovering around take advantage of the chance and try to get in. But when they have gone through the fire of your cigarette they become purified, and are quite harmless by the time they get to your lungs. When you are not smoking, the open plaster is plugged with a cork. This is to conform to the law in localities where the au- thorities think that in- fluenza can be cured by legislation. You must remem- ber not to stick out your tongue, and to be very careful when you sneeze lest you blow out the cork and let in the germs. Duncan, the inventor, at first thought of having an outlet for the exhaust smoke, but he found out that such refine- ments would violate the law. On _ second thought, he concluded that there was double : enjoyment derived from Smoke if you want to, even though llowi h k you wear an influenza mask. Corn- swallowing the smoke a plasters fitted to the mask, inside couple of times. and out, supply the necessary hole A young mechanic spent a year constructing this 300-pound church model from bits of steel and brass He Has Revived the Lost Art of Church Modeling BROOKLYN mechanic has spent more than a year making a church out of bits of steel and brass. A chisel, a hammer, and a file are practically the only tools that he uses. The height of the model is 53 inches, the length 82 inches, and the weight is ap- proximately 300 pounds. Chimes and an eight-day clock movement have been installed in this.miniature church. They resemble some- what those of Westminster Abbey. The clock strikes every fifteen minutes, and the chimes ring on the hour. This Stone-Spreader Does the Work of Many Shovelers NSTEAD of dumping stone at the side of a road, much time and money can be saved by spreading at the time the stone isdumped. Con- the extent of which is determined by the operator. The machine is seven feet four inches long, and can be used in connection with any of the tracting two operations into one is, as a rule, economical, and the present is no ex- ception. The construction of the device used for spreading is neither diffi- cult nor expensive, and the the gain in the first con- tract. When crushed stone is delivered by truck, the spreader is fastened behind. The body is raised and tilted for dumping, and as the stone pours out upon standard types of trucks. When a road is too wide to be covered at one opera- tion, but not wide enough to permit of two, a drag is attached to the spreader, which drag scatters the stone on both sides for an additional space. The action is almost entirely automatic, and _ unskilled labor can use it as readily as skilled. At this time, when every effort is being made to build up an extensive haulage sys- the highway the spreader els it to an even depth, 33 A drag is used with the spreader if the road tem, any advance in road- is only slightly wider than the spreader making is important.

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Canny Farmers Planned This House of Hay OME farmers of Sunnyside, Washing- ton, had about six hundred tons of hay which they wanted to sell at just about the time the annual county fair was due. They suggested that the fair building be made of hay, and then graciously offered the use of their bundles. The hay house was a large square struc- ture, twenty-five feet high. Inside there was plenty of room for all exhibits, a rest- room, an information bureau, and a stage for the customary vaudeville show. When the fair was at its height, the kindly hay-lenders suggested that the hay be auctioned off; and the happy visitors bought it all, paying a very high price for it. Brooms in Perfect. Formation Sree eABLyY the largest thing you can get today for a dollar is a broom. That is all very well for you, but dealers be- grudge the space that brooms take. A broom-rack like the one shown above holds sixty brooms. It takes up very little room in the dealer’s shop, and the wheels on it make it an excellent push-cart. Wires running from front to back keep the brooms from swinging from side to side and getting mixed up with one another when the rack is in motion. There Are Pipes in the Pipe INCE Los Angeles has been captured by moving-picture companies, an ordinary merchant must do much queerer things than the movie people to attract attention. Now, a2 man named John had a pipe shop there, and he wanted everyone to know it. So he built a metal pipe ten feet long from the tip of the stem to the bottom of the bow!. He mounted it on his delivery wagon, and uses the bowl for carrying packages. On the bowl’s outside he naively confesses that ‘‘The shop that John keeps is the shop that keeps John.” Typewriting on a Bureau Drawer BED, a bureau, and a chair are about all the furniture usually found in a so-called furnished room. The inspired typing author sojourning in one of them finds no place in which to stand his machine. The window-sill is too narrow, the dresser-top too high, the chair too low, and the bed too wabbly. One man discovered that a bureau drawer made an excellent resting-place for a typewriter if the contents were dumped out and the drawer put back in the groove, bottom up. How to Take Your Pig to Market you really can’t put a calf, cow, or pig in the back seat of your automobile if you have any sense of the fitness of things. Yet you can’t expect any one of them to trot patiently behind, even if you throw a rope around its neck. How, then, are you going to deliver animals after you have sold them? James McAlister, of California, answers this question by building the animal trailer shown below. The back piece on the wagon is dropped down to make a gang-plank when the animal gets on or off. Mr. McAlister’s bull doesn’t look very happy.

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niture spired which r, the abbly. -ellent d out ' your hings, shind, e you n by yn the nimal py. ~ May, 1919 : — rT a x : You’ve Often Heard of Hearts of Stone GTONES have a disturbing habit of assuming human ~ shape. Noses are their favorites, and a great deal of excursion money has been spent for the purpose of seeing these rocky noses. But the stone shown above, which is found in the San Bernardino Mountains in south- ern California, is too sentimental ‘to bother with noses. It has a large heart, and it wears this heart where everyone can see it. This heart of stone holds thirty feet of water; yet many senti- mental folk have braved death through drowning therein, in order to carve.their names on the heart’s sides. One Plane Lands on Another Plane’s Back ‘THE old adage about salt on a bird’s tail does not apply to an airplane, which needs something more powerful than salt—another airplane, for instance. The picture herewith shows how effectually this may be done. One small airplane on a large empty field was getting ready to fly. Another airplane was coming down, and, in spite of the vast choice of landing places, came down on the first plane’s tail, spoiling its flight and also its tail. Where- upon both pilots crawled out un- harmed and looked at each other in aston- ishment. : © Keystone View Company Ex-Subjects of the Ex-Kaiser ERMANY has lost since 1914, be- sides other things, seven million Africans like those in the picture below. Judging from the primitive way ‘in which they live, politics doesn’t bother them much and they don’t care who owns them. The men hunt their own meat in the forest in which they live, and the women cook. The one with a pole in her hand is -pulverizing grain for bread. When these Africans want to buy beads, they pick some tobacco leaves (shown up front) and use them for money. They live in huts buil€é on stilts to protect themselves from Afri- can mosquitoes, which hug the ground. © Underwood & Underwood Te Tr oe ee eee The Tale of a Leaky Trolley Pole A TROLLEY - pole was erected in Chicago. lt was just like any other trolley pole—made of cast-iron with a hollow center and set in a con- crete base. It had been up but a very short time when water started spouting from its top in two thin streams, and continued to spout. The trolley company asked the Department of Public Works to find out what the trouble was, and this was the answer: the base rested on an old water-pipe and had broken through it. °The water rose in the hollow pipe be- cause water seeks its own level, and this water’s level must have been higher than the streets of Chicago. Unfortunately, the leaky pole is located not on a dry country road but in front of a jewelry shop in a crowded section of town, where its fountain spray falls on unreceptive pavement. It is most. unwelcome. The jeweler doesn’t like it; neither do the passers-by nor the trolley cars. But unless the trolley company takes out the pole, mends the leak, and then puts the pole back again, the water will continue to rise and fall. — “

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Popular Science M. Not a Bit of Leather in These Shoes a & The mechanical cobbler takes on the canvas shoe and reduces the labor to a minimum

The patterns of the uppers are so laid upon the sheet canvas i that every available inch of space j . \ acts ee. , is utilized. There is practically no e i ‘ me a fh material wasted by this method

The assistant at the left of the illustration is shown holding the _knives that cut through twenty thicknesses of material at once

Photographs © Publishers’ Photo Service

A mechanical Jess Wil- lard that delivers mms r\ao os ‘ : twenty punches. to One of a pair of hinged ie -e ; sa the eyes every ten plates between which f 4 ' es * <=. seconds is an inge- slabs of rubber are pressed by (ae nious machine which to shape them into soles. eee ( . 7 * a4 clinches the hooks and The surplus rubber is —_ “se ¥ S'S ’ wer eyelets into the uppers thrown back into the 2a mixer and melted again

When the uppers are made this machine pulls them smooth The shoe finally goes to the ovens, where the vulcanizing over wooden lasts, turning down the edges under the sole process cements the soles, heels, edging, and other parts

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What They Do When There Are No Fires to Fight Six men with but a single thought—promotion; and so they are reading books on building construction, fire prevention, and anything else that will help them These seven serious souls are proudly holding a framed shawl which they all conspired to make. They have generously decided they will give it to the Red Cross lf no fire inconsiderately in- terrupts him he turns out one . porch swing a day, increasing Intrigued by the shape of his income by selling them the base of the base-burner stove, he uses it as a model for flower-pots. They are made of cement and painted \yheoa a \A el Van When he isn’t playing with fire he plays barber and cuts the hair of his comrades, even unto his chief His side issue is cobbling. When he has mended and patched ‘the boots of his fellow firemen, he fixes the shoes of his family, so that no onecan say, ‘“Who is worse shod than a shoemaker’s wife?” They take turns rescuing each other from imaginary fires to keep in trim. The rescuers carry the rescued over one shoulder, flinging an arm around the victim’s leg and holding hands with him 37

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N investigating any phase of life, one should keep as near to nature as possible. Thus the ordinary little fish-globe, usually strung up in a win- dow by three cords, is about the big- gest monstrosity that it is possible to conceive. It could not be further from nature’s method: pools and ponds are not hung in mid-air. The ordinary aquarium, lighted on all four sides as well as from the top, is not much better, because nature does not light her pools and ponds in that way. The best thing in which to breed goldfish is a tub, pail, or pan in your back yard, where there will be a limited amount of sunshine. Perhaps even better are sunken tubs and tanks. These should contain various aquatic plants, and should be so located that the trees afford just the proper alternating ' glints of sunshine among the shadows. Goldfish are bred in the spring. The percentage of fancy fish that breed true to type is small, but in this is a great fascination. It has been claimed on good authority that one should be satisfied if ten per cent come true. Good, hardy, outdoor stock may be obtained most cheaply in September and October, when the dealers are usually willing to sell their older fish. It is a good plan to get everything started in the autumn, so that all will be in readiness for the first signs of breeding in March of the following year. Spawning fish should be well fed, but it is not neces- snails like these. By Edward F. Bigelow sary, as some people think, to feed them every hourinthe day. Breeding fish should be kept in the proportion of about three males to one female— though if special results of crossing are desired only one male should be used. The tubs or tanks should be well supplied with aquatic plants. Make sure that there are present no snails or other enemies to the eggs. Goldfish breed well in wash-tubs and dish-pans. Perhaps the best place of all is a tank sunk in the back yard Take a Little Joy to the Goldfish Popular Science Monthly ‘ Water hyacinths, myriophyllum, and similar plants with finely divided leaves are useful. The eggs are dropped on these plants and the sticky globules adhere to the feathery leaves. A good female will lay more than a thousand eggs. There is a never-ending source of amusement in watching through a microscope the progress of the fish embryo during the time of hatching. This takes from three to fourteen days. Warring Snails Have Invaded a Town The whole town of Sidney, Ohio, is coated with This picture shows them greatly magnified, each snail being no larger than a pin-head 38 OME time ago Sidney, Ohio, was invaded—-not by Germans, frogs, or fleas, but by slow, stupid snails. They were very small, no larger than a_ pin-head, and they came so slowly and silently that they had taken complete possession of Sidney before Sidney realized it. Their official name is Vallo- nia puchella. This is how they were discovered: two Sidneyites walked along the street to- gether. Said the first to the second, “It seems as if the sidewalks were covered with powdered glass; don’t you feel it crunching under your feet?” The second one pulled out a microscope, and they both knelt down. What they saw was a solid coat of very small snails. The sidewalks were completely covered, and so was the rest of the town. Snails are vegetarians. Hence this army menaces the growing greens of Sidney.

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n, and leaves ved on obules \ good yusand irce of ugh a e fish tching. 1 days. 0, was frogs, snails. all, no :-head, ly and taken Sidney ed _ it. Vallo- were neyites eet to- to the if the d with 7ou feel rfeet?” ed out y both ley saw y small cs were and so own. arians. aces the ley.

May, 1919 ‘prepared to start the vessel

“She Starts, She Moves, She Seems to Feel—” The intricacies of ship-launching explained or water; cheers; the smell of smoking grease; fluttering flags; the excited shouts of invited guests and of the workmen whose toil has completed the vessel as she splashes into the water—these are the out- ward or visible signs of a successful launching. To the average spectator ata launching the thing seems very simple. The sponsor gives a signal, it would seem, when she is ready to break the bottle on the vessel’s bow, and then something or other happens to start the vessel on her path to the near-by water. Contrary to the general opin- ion, the sponsor does not give the signal to the workman when she is ready to break the christening bottle over the ship’s bow. Instead, it is the workman who gives the signal to smash the bottle when he himself is \ BROKEN bottle of champagne on her way to the water. Rehearsing the Christening To be sure that no slip-up occurs at these functions, the christening party is usually re- hearsed the day before. <A dummy bottle is used. But there is a right and wrong way of breaking the bottle. Miss Flora must watch for a signal from the man in charge, and break the bottle on the cord against the bow of the ship as the big

aoe TRIGGER HOLDING SHIP BACK. LAUNCHING WAYS READY TO START

TRIGGER. HOL BY OPENING VAINE aie Pull the trigger and launch your ship! is the latest thing in launching methods. The “trigger,” fastened to the - Stationary ways, holds fast the launching ways until a valve is turned to let out the liquid, thus releasing the trigger and ing the vessel on its first voyage. side of the ways has its own trigger By Joseph Brinker hull begins to move. But she must not wait too long. Unless She swings it in just the right way, the bottle will not break, the hull will get beyond her reach, and the ship will go unchristened. Seamen believe that a ship is hoo- dooed at the start if she is not properly

Just taking the water. A_ typical scene at the launching of a government- built ship. It all looks easy enough to the crowd of spectators looking on christened. In the launching of a government supply boat, recently, a young woman was saved from this embarrassment by the quick wit of a workman on board the hull. While leaning over the bow, he saw that she had not broken the bottle, and by “snapping the whip” he did the actual christening for her. He re- ceived a gift of ten dollars for his quick thinking. Two Ways of Launching Two general methods are employed ° in launching a ship: the one endways, stern first, and the other sideways. Each method has its own particular advantages. Along the Great Lakes more boats are launched sideways than endways. But, no matter on what plan the 39 vessel is launched, there are certain fundamental principles that hold good In any case. The first work is the placing of a series of keel-blocks arranged in one line perpendicular to the water in the endways method. The height of the tops of these blocks 18 SO arranged as to form a straight line of support for the vessel through- out its longitudinal length. Shifting Thousands of Tons These blocks support the en- tire weight of the vessel at its center line. The weight at the sides, as shown in the first of the diagrams at the top of page 40, is taken by side cribbing or shores. These keel-blocks and side shores carry the entire weight of the vessel while she is being built. Looking at the keel-blocks from the side of the vessel, those at the front are higher than those at the » rear, so that the boat is built on an inclination, in most cases of about three sixteenths of an inch to the foot. To launch the vessel, its entire weight is transferred from the keel-blocks to the launching set up on either side of the keel-blocks at an inclination of about one quarter inch to the foot. This transference of the vessel’s weight may be done by one of two methods: namely, by the wedging up of the launch- ing ways as shown in the figure already referred to, or by the sand-bag method illus- trated at the top of page 41. To understand either of these methods, it is perhaps best first to point out the relations of the launching ways, the stationary ways, and the keel-blocks. The keel-blocks simply support the weight of the vessel while it is being built. The stationary ways run almost the entire length of the ship on both sides of the keel- blocks at points about midway be- tween the keel-block and the sides of the hull, and are constructed of a series of heavy timbers suitably tied together. These stationary ways are put in place shortly before the vessel is ready to be launched. The tops of the ways are then coated with grease specially prepared to suit the weight of the vessel and the estimated num- ber of days before the launching will take place. The thickness of the layer of grease is also varied to meet

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eimgeget eS EEE 3-POINT SUPPORT WHILE BUILDING LAUNCHING WAYS KEEL~ BLOCKS CAN NOW BE REMOVED Popular Science Mon TIE=RODS KEEL“BLOCKS SIDE SHORES the conditions and the time of the year in which the launching takes place; for it must not melt before the launching date or be forced out when the weight of the vessel has been transferred to the launching ways. Getting Her Ready ‘to Launch The launching ways are placed directly above the stationary ways, and are separated from the stationary ways only by the film of grease. The space between the tops of the launch- ing ways and the hull of the ship directly above them is filled in with blocks between which are two wedges, which, when driven up on STATIONARY WAYS SIDE SHORES Here are the principal stages in launching a vessel endways. First the weight of the ship is supported by keel-blocks and side shores; then, just before the launching, the stationary ways are put in place and the tops covered with grease; * next the launching ways are placed on top of the stationary ways, and wedges and blocks are driven between them and vessel is at this time supported on the two launching ways, so that the keel- blocks can be removed. The launch- ing ways are prevented from spreading, while the vessel’s weight is upon them, by means of steel cables and turn- buckles that join the two ways. The vessel is then ready to be launched. The Sand-Bag Method The other method of transferring the weight of the ship from the keel- blocks to the launching ways is by means of sand-bags. The ship is built each other, force the blocks into close contact with the hull. When these wedges on each of the launching ways are driven up far enough, the entire hull is lifted up slightly from an inclination of three six- teenths of an inch to the foot to one quarter of an inch to the foot, and there- by lifted clear of the keel- blocks. The entire weight of the LAUNCHING WAYS MOVE WITH SHIP GUIDE|-RI BY AWYER'S ee ee ae STAGING: GREASE BS TUMBLING STATIONARY WAYS LAUNCHING WAYS SAWED HERE LAUNCHING WAYS SAWED HERE “Saw off!” is the order, and here you can see what is hidden from the ordinary spectator—the details of how the launching ways are cut through to free them from the stationary ways —— EI Where the crisis comes at a launching. The upper sketch shows the ship resting on the ways, her weight evenly borne. In the center figure she is partly in the water, her weight acting down at the point W, while at B, the center of buoyancy of the part of the ship afloat, the water is pushing up. The bottom figure shows the moment when, as B and W move to- a. gether, the boat tends to pivot about a point near the bow and crush the ways or- the keel and the bottom plates of the hull on the keel-blocks in the usual manner. Before the launching date, the top blocks on alternate keel-blocks are knocked out of place by means of a ram, and bags of sand are placed between the second blocks and the hull of the vessel. Each bag of sand is then wedged up tightly against the hull of the vessel. After bags of sand have been placed on the tops of each of the keel-blocks by this method and the weight is transferred to them, the 40 \STATIONARY CRIBBING OR CHOCKS. “STATIONARY pways 9 =e WAYS the ship; then the wedges are driven in, lifting the ship from the keel-blocks and transferring its weight to the launching and stationary ways; and—last step except the actual launching—the keel-blocks are knocked out, leaving the vessel ready to slide into the water. the launching ways from spreading under the weight Tie-rods keep stationary and launching ways are get up in the manner just outlined. When the weight is to be transferred to the launching ways, the sand-bags are cut, thus allowing the sand to flow out and lower the hull upon the launching ways. launched. The five steps in this opera- tion are clearly shown on page 41. The critical point in the operation occurs just before the vessel becomes entirely water-borne, or supported by the water instead of the launching ways. At this time the boat tends to pivot about a point near the bow, and it is necessary to build up a wood cribbing at this of the hull, so as to prevent the keel or bottom plates being crushed in. Similar blocking between the launching ways and _ the rear portions of the hull is employed. LAUNCHING WAYS SAWED SHIP AND LAUNCHING WAYS GREASE SAW CUT Details of the operation of “sawing through,” showing how the launching and stationary ways are bolted to- gether and how the saw cut sets the ship free to slide into the water The ship is then ready to be. point to distribute the strains over a larger area’ of the hull (generally nar-- row at that point) from 4 E4 ef iS 01 W T sl ve st al pe ee ae eee sO Pe ae a ee wor oo ey

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- are set . When i to the are cut, out and unching y to be. S$ opera- 41, peration becomes rted by unching to pivot the bow, to build x at this ite. the yer area‘ prevent

“sawing unching ited to- sets the | > water

3-POINT SUPPORT

ALTERNATE KEEL~BLOCKS '

3-POINT SUPPORT [FA a 2-POINT SUPPORT

LAUNCHING WAYS Lx |

The sand-bag method of launching. Telling the story from left to right, the figures show, first, the ship’s weight supported by keel-blocks and side shores; next, alternate keel-blocks are knocked out of place and bags of sand substituted; then the bags 5 I oe | ew EL/BLOCKS SAND-BAGS WEDGES— DRIVEN IN \ STATIONARY ) STAY-RODS RE | WAYS STATIONARY WAY'S SIDE SHORES LAUNCHING WAYS

is shifted entirely to the sand-bags, and after the stationary and launching ways are set as shown on the opposite page the bags are cut, allowing the sand to flow out and lower the hull down on to the launching ways. As in the other method, stay- or are wedged up tightly against the hull. The weight tie-rods are used to keep the ways from spreading The next step in the endways launch- ingis the manner in which the launching ways are started to slide on the layer of grease between them and the in the sawing method to insure that tons to be forced into the cylinders the launching ways on each sidearecut by the tendency of the launching through at the same time; other- ways to slide on the stationary ways by reason of their inclination.

stationary ways on which they are built. This may be done by the sawing or by the trigger method. Sawing through the Ways In the former, the launching ways are securely bolted to the stationary ways at the end farthest from the water. When the vessel is ready to be launched, men with ordinary cross-cut saws mount small platforms especially erected for the purpose and saw through the launching ways. This breaks the connection between the launching ways and the stationary ways. Great care must be taken

Side launching has the advantage of requiring only a small basin of water. The launching Ways are built as in endways launchings. The figures, beginning with the upper one, show the three stages of the operation: the vessel as she rests on the stationary ways, just starting to slide, and all clear of the station- ary ways and about to drop into the water

A close-up view: of a ship rest- ing in her cradle on the ways wise the ship might be given a wrench that would be more than the uncut ways could withstand and lead to their collapse. The Trigger Method The trigger method is generally considered the more modern, es- pecially for ships of large ton- nage. Notches are cut in both the launching and the stationary ways at some point in their length, but not necessarily at the ends, and the triggers are pivoted to the stationary ways. The upper end of each trigger is in contact with a cap inserted in the notch in the launching ways, and holds them fast to the stationary ways. The lower end is fastened to a piston inserted in a small cylinder filled with glycerine and water. When the boat is ready to be launched, the liquid is allowed to run off both the cylinders simul- taneously, thus permitting the pis- 41 This causes the upper end of the triggers to move around their pivots out of the notches and thus allow the launching ways to move without interference. Side launching has the advan- tage of requiring only a small basin of water. Advocates of this plan claim that there is less © strain to the ship in the drop off the ends of the ways into the water than there is in launching a long vessel by the endways method. The steps in a sideways launching are shown clearly. One view gives a plan view of the arrangement of the ways and the position of the launching levers. Another shows the details of launching lever and how it operates. LAUNCHING ROPES a - 4.

WATER’ EDGE Plan view of vessel ready to be launched sideways. Note the launching ropes, and see diagram below vit. \ \

—

At the left the launching lever holds the launch- ing ways in place. At the right the rope has been cut, the pivot timber has fallen, and the ways are free to slide as the levers pull from the notches

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With this overhead system, consisting of a track, traveler, and endless-chain hoist, one man and a boy are able to do work for which six men were formerly required Wheels Overhead Answer Many Shop Trucking Problems VERHEAD carriers are replacing floor trucks in many small work-shops as well as in big manufacturing plants. The tracks can be suspended from the ceiling so as to give ready access to all parts of an establishment. Less cost as well as convenience fight on the side of the overhead system, since with it one man can do work for which several using floor trucks would be required. For instance, the man in the illustration is at work in a large nursery plant, moving boxes packed with trees. The boxes, when ready for shipping, weigh from two hundred to fourteen hundred pounds. With the overhead track, carrier, and familiar endless- chain hoist one man with a boy helper handles boxes that formerly required six men to move. The variety of uses to which the overhead sys- tem has been adapted illustrates the scope of its usefulness. The sys- tem shown here is in successful operation in garages, where it lifts out engines, transmissions, and other parts, and car- ae ries them to and from the ‘ repair section; in paper plants, where it handles heavy rolls; in stock- rooms, where it comes in handy in distributing ma- terial when used with a rolling ladder; and, sup- ported by I-beams, for handling huge steel rolls. . ~ ws goes AND NEOT CLOCK MECHANISM TILING DOOR LOCK The tilting platform locks the door when the hen is on her nest, and a drop of colored fluid falls on her back Creating a Sense of Cleanliness in the Hog pone difficult problem of keeping pigs and mud away from each other has apparently been solved by.a southern California ranchman. This man’s place, like those of many farmers, has a stream of running water— in this instance an irrigation canal. He resorted to the simple expedient of building a pen from his hog pasture into the ditch, which was shut off from the field at every other point. This fence he made hog-tight. Then he built a sloping platform of light planks Yes, pigs do like - clean water— when they’re al- to prevent the formation of a mud-hole and to keep the water on one side of the bank. Now his hogs are the cleanest live stock on the ranch. Many other farmers are adopting the same method, which works well even in a small creek. Marking the Dutiful Hen that Lays the Egg T must be an astonished hen that enters the nest invented by Ellsworth Tilden of Columbia Falls, Mont. She mounts the nest. It yields slightly beneath her weight. It seems to be on one end of a small seesaw or tilting plat- form. The other end of the platform rises far enough to block the door and prevent intrusion. As the hen entered, the door pushed a small lever that started a clockwork device overhead, which was still going. A drop of colored fluid falls and makes a spot on the hen, She hurries out, leaving behind her an egg. As she starts toward the door, the front end of the seesaw yields slightly under the influence of her own weight and the force of a coiled spring at the back. She pushes her way out into the sunshine. Her owner notes with satisfaction the . purple spot on her white plumage. He knows DISN OF COLOR which hen is laying the If a farmer owned sev- eral hens he would, of course, need several pat- ent nests, each dropping a different colored ink. Unless he bathed all his hens every night he might easily run into this diffi- culty: a daily layer gets into a red nest today anda the blue and red working upon causing a mix-up, Popular Science Monthly 7 lowed to have it ® blue nest tomorrow. With together, she will register” purple—the lawful color” of some other hen, there

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vay ya like r— pen — ; Off lade inks May, 1919 : Keeping Oil at Home b Fencing It In e early days, when both oil es oral gas were thought to be as inexhaustible as the ocean, few persons gave a second thought to the sight of a few thousand barrels of oil spouting into the air and running off into a river or sewer. There was always plenty more where the wasted oil originated, so why worry? Times have changed. We no longer encourage waste even if we know that an exhausted supply can be replenished... That is why a Western oil refinery is sur- rounded by an oil-tight emergency fence. If a tank breaks up, the fence gates are closed and the yard becomes an oil lake, the oil being This forest fire finder automati- cally scales the distance, draws the line of sight, and measures the angles An oil-tight cement fence which will convert the yard into a lake and save oil if a tank should give way retained long enough to pump it to a place of BEAD safety. There are no j open sewers within the yard. It would be a great oversight to plan a fence of this kind, and then have the oil run GROOVE ptt ee a. a i The lookout is the eye of the protec- tive organization against~ fire..- .He must be on watch from dawn till dark It Spots Forest Fires at Once HEN a forest fire is discovered by a lookout, everybody at the station gets busy at once. The volume, character, and drift of the smoke are at once recorded and reported. The direction from the station is read and recorded ac- curately in degrees and minutes. Even the ‘‘angle of depression’”’ is observed. Prompt action saved much valu- able timber last year, and this prompt action was due largely to equally prompt and accurate re- porting. An Oregon fire was re- BEAD through the gutters to ported by three separate stations, The newer types of instruments are so constructed that even unskilled observers, or observers of only moderate training, can make ex- tremely accurate observations. One of the latest types of ob- serving instruments automatically scales the distance on a map, draws the line of sight, measures the angles, and can be moved on a track to a point where the best view of a fire can be obtained, without requir- ing releveling. Which is “going some.” Make the Tractor Do the Leveling BIG job of leveling had to be done at Hanford, Cal., and labor was so scarce that the enterprising contractor to connected his tractor with a six-foot scraper, rigged up a “Al platform on the rear of the scraper on which to stand, and the sewer; and yet, just such errors have been made by designers of safety devices and schemes. The ends of the concrete slabs fit in grooves in the posts, while the sides of the slabs are tongued and grooved so they will fit together in a tight seam. © The slabs need not be cemented, and the fence will then be a portable one, There is no reason why a fence of this type should not be used around any kind of Property. Its portability and the simple method of setting up the blocks render it very adaptable. The slabs are tongued and grooved so as to fit together; not cementing the slabs makes the fence portable then ran extension arms from the tractor controls, so that he could operate the machine from the platform. This did away with the necessity for an extra man. In leveling for skyscrapers and other high buildings, steam-shovels and scoops of various kinds have been tried Labor being scarce, he connected his tractor to a six- foot scraper and did a job of leveling without help from time to time, with varying success. Whether the scraper and the tractor could be used in such under- takings is a question worth looking into. Digging railroad cuts and other leveling operations along railroad beds might aid of the tractor and the scraper. The cheapest methods are usually adopted in commercial fields, and the present method seems to come up to the requirements. also be performed with the. —" ee ee er . =n ==t + - == ee re

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Here It Is—the Magic Wheelbarrow Major Frank B. Gilbreth’s invention, which will do everything but talk While the wheels of the barrow are serving any one of.a dozen purposes, the rods make a fine frame for a tent to house a field Having helped out in every de- partment of the day’s work, Major Gilbreth’s invention can be used at night for shelter This most modern of wheelbar- rows not only carries the ce- ment to the building site, but provides a quickly assembled telephone set for the surveyor framework for a mixing-board Should you wish to un- load a freight-car away from a platform, just roll up the Gilbreth magic wheelbarrow, and, pres- to, there are both the cart and the inclined plane On wheels it carries For the topographical supplies over the rough logging road to camp, and now, dismantled, it provides the makings of a convenient. table surveyor doing field work far from towns the magic barrows be- come carriers and pro vide shelter and even an efficient map-board Rods from the barrows form the framework of a comfortable shack, and the miners use one : of the wheelbarrows . they come in, for the for a comfortable divan unexpected - use of : ' 4 : ee thawing out dynamite : or eas sé sticks for blasting ‘ We've been neglecting the wheels, but here you ‘see how - handy Where trail or “tote road” is too rough for wheels, the dis- mantled barrow still provides a handy means of transporting materials or camp equipment or helping out on a_ portage

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Experience has shown that the mask that defied the Hun gas won’t always save the fireman who wears it ina cellar fire Engineers in charge of refrigerating apparatus often face deadly peril from ammonia fumes as they distill coolness for us. Perhaps a gas- mask and an ammonia alarm would solve the “safety first” problem There’s no mili- tary pomp about this job, but the sewer worker knew the gas peril long before the soldier did Chloride of lime even in barrels gives off chlorine, the gas that first made the word gas infamous on the battlefield The deadliest onion loses half its terror when he or she who peels it is properly equipped Always carry your gas-mask to restaurants and have it at the “ready”: it may save you from a cheese barrage Perhaps the “whisky breath” hastened prohibition: we suggest the gas-mask as a remedy until July first

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ARCONI, pioneer of radio M communication, believes that it is possible to com- municate with inhabited planets —if the newspapers report him correctly. Mysterious disturb- . ances are recorded by sensitive radio receivers. Are messages coming from Martians frantically trying to communicate with us? Perhaps. At any rate, Marconi predicts the possibility of sending out electric waves to the planets. And if a great radio engineer believesin communication between worlds the matter is not to be lightly dismissed. It is older than radio-telegraphy, this idea of talking to the’stars. Be- fore Marconi sent his first wireless message, it was suggested that we might flash signals into space or draw geometric designs on large surfaces in electric lights. Flammarion, Schi- aparelli, Lowell, all of whom passed a life-time in studying Mars, have sponsored the scheme. How Much Power Would It: Take? Now, the electromagnetic waves used in radio-telegraphy have this advantage over light waves: Atmos- pheric dust and clouds, both of which obscure light, offer no obstacles to the long waves that Marconi uses. What about the electric eyes, the receivers, that see these radio waves? The human eye is probably more sensitive —about ten times as sensitive, ac- cording to recent measurements. But the receiving area exposed to the in- coming waves can be adjusted within wide limits, unlike the pupil of the eye, the size of which is fixed by nature. Suppose, then, we try to send a tadio signal to Mars: How much power would it take? -— Talking Across 34,000,000 Miles to Mars How can the Preiident congratulate some Martian Republic on the celebration of its Fourth of July? By A. J. Lorraine Perhaps we shall have to fall back on light, after all. We shall have to establish a code based on the use of electric lamps or searchlights. But how? One suggestion is that we should make a huge diagram in some cloud- less part of the earth of a well known theorem in geometry. ‘‘The square on the hypothenuse of a right-angled triangle is equal to the sum of the squares on the other two sides.” That might be a good one to begin with. Every school-boy knows it; an educated Martian ought to re- cognize the diagram at once. To show that they understood, the Mar- tians might reply by drawing in light some equally well known Euclidean proposition. Picture would follow picture, until at last perhaps some kind of a code would be established. Or, more simply perhaps, something like the Morse system could be applied to flash signals of long and short duration. What can be seen on Mars? More than you probably suspect. A circu- lar or round spot fifty miles in diameter can be distinguished with a good tel-

We ‘ask the _ engineers who designed the radio sta- tions used on the earth. About 400 kilowatts (540 horsepower) are required, they tell us, to communicate under normal conditions over 4,000 miles. Greater ranges are obtained when the conditions are favor- able. It looks black for wireless telegraphy. Still, Mr. Marconi may have reason for optimism. He may see possibilities in the use of directed waves, possibilities that are not obvious to others not so well informed. lard’s

THE NEW YORK DAILY NEWS __ Popular Science Mont rt

escope under favorable conditionss a spot, for example, as big as London

A dark line three quarters of a mil in width would also be ‘visible. Bri

points of light at night, or a ine lights, might be seen, even if narrow than three quarters of a mile. Seg lights have been made for which” brilliancy three times greater than't th of an ordinary carbon electri¢ a lamp is claimed. They are abo two thirds as bright as the sun. @ of these installations is described

having a total of 1,200,000,000 candle power. How blindingly ‘dazzling it must be! How far into space it must penetrate! Yes; but Mars at its nearest is 34,000,000 miles away. Talking by Light Flashes Talking to Mars by flashes or by lines of light would at best be expen- sive. Generally speaking, only about two or three per cent of the energy that drives the dynamo by which the light is produced appears in the form of visible radiations. Seven per cent, it is true, is claimed for the mercury vapor lamp and the flaming are. But how pitifully small is even that & ~~ geven per cent! Again, the

Would, perhaps, some enterprising Martian with an eye'to business establish an interstallar corre- spondence school, and patronizingly announce subjects for Earthmen and other undeveloped intellects? “Elementary Courses” in mysterious 46 GREATLY SIMPLIFIED [| Proncincy IN TREATMENT ESPECIALLY MENTAL ARFrHMETiCc| DESIGNED FOR EARTH- WITH TRANSFINj77] MEN AND OTHER, MARTIAN OFFICE OF THE I.C.S. es prea Russia— |__ __EDUCATL ONAL <i eye, marvelous though it may Reminiscences A R be, has its limitations. é nialenhiat sae teeg It is true that even with- a SCHOOL out a telescope you could, in absolute darkness, see @ SPECIAL COURSE ELEMENTARY | light of one candle-power at MATHEMATICS! —_ PSYCHOLOGY a distance of sixteen miles, according to some recent and very accurate measurements NUMBERS. onesie a that have been made—but v . ° ¥ SSoaad acme, IN TRE UGH only just see it and no more. PeicHOorogy! — MENTAML HIE Lomi If energy thus received could address:

be utilized to heat a pound of water, it would require degree Fahrenheit. But this extreme sensitiveness is needed about 267,000,000,000 years” to raise its temperature one™

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expen- about energy ch the orm of nt, it is vapor t how that n, the it may with- could, see @ wer at miles, nt and ements 1e—but > more. — d could pound require years re one” ut this : needed if the Martians are superior beings, as Professor Lowell has argued, what shall we say tothem? Something simple, something fundamental, to begin with. Thus we might present to them in electric lights strung in the desert of Sahara, as we have shown here, the proposition that because the eye has very serious limitations in another way: The pupil, even when widely dilated, measures only about one tenth of a squareinch in area. It thereforecatches only a very small part of the light sent out by a distant object. A telescope helps, for it is a light-gatherer. But suppose that we could send signals of some kind to Mars. What about the Martians? How could we make them understand? Lowell tells us that Mars is very’ much older than the earth. Therefore, one might rea- son, the Martians have had time to _ evolve into creatures intellectually far superior to ourselves. The Superior Martians How ean we talk to this superior being? Difficult as it would be to establish a basis of common under- standing, the obstacles are not in- superable. Helen Keller, blind, deaf, and dumb, has learned how to communicate with her fellow beings. How do we know whether a Martian has eyes? We do not know. But, at least, we can make some deductions based on what we know about nature. The human organism is not a mere accident. It is the result of a definite set of circumstances. The sun sends out light: so we have developed eyes to see. Sounds are transmitted by the atmosphere: therefore we have ears to hear. Heat is sent to us by the sun: we are equipped to feel it. All this applies to innumerable species of animals. So, too, are ears common to many creatures. The conditions on Mars are dif- ferent from the conditions on the earth. But it receives light and heat from the sun, just as we do. Therefore the Martians, we may well suppose, are able to see light and to feel heat. Mars has an atmosphere that carries sound; therefore the Martians have ears. In other words, if under the conditions described many kinds of creatures on the earth have developed eyes, ears, and other senses, it is rea- sonable to conclude that the Martians have developed senses like ours if their planetary conditions are similar enough to ours. Now, if the Martians are superior beings, as Lowell has argued, what shall we say to them? In the beginning, something simple, something funda- mental. By way of casual conversa- 47 “the square on the hypothenuse of a right-angled triangle equals the sum of the squares on the other two sides.” The Martians ought to recognize that Euclidian theorem, and reply with another. Picture would follow picture, until at last some kind of |interstellar code would be established tion, let us flash to Mars the news that twice two is four. Irrelevant, you say? Not nearly so irrelevant as saying “How do you do?” to a friend on the street who is obviously doing very well. The mere fact that we of the earth have actually bridged the immense chasm that separates us from Mars ought to produce an effect so dramatic that the Martians would condescend to speak to us.. Perhaps they would regard us with mingled curiosity and patronizing kindness, as if we were rather clever children. What Would They Tell Us ? What would the Martians have to tell us? Their world is dying—dying for lack of water, Lowell tells us. Would they paint terrible pictures of the tragic end that is in store for them? Or would they furnish us with thrilling descriptions of their marvelous achievements in science? Would, perhaps, some enterprising Martian establish an _ Inter-Stellar Correspondence School for ‘‘Earthmen and other undeveloped intellects” ? Who knows? At any rate, if it amuses you, you may _ speculate about it.

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This carburetor auto- matically adjusts itself No, she isn’t making up, but saying “‘Home, James,” to the chauffeur through her camouflaged. telephone A new coupling with a cone nozzle fits any 5/16- to %4-inch plain or armored hose Originally built to : meet he . mesa Press the brake-pedal and this stop signal works service, this clectric automatically as long as the brake is down valve-grinder seats a new valve in from six to ten seconds Popular Science Monthly This truck went out of its way to carry a fourteen-ton engine- attempted by anything other than a railroad flat-car and teams New Inventions for Proving that peace-time back into their own after For the driver’s convenience the modern motor-truck has a two- step running-board with wooden treads to prevent slipping —) ae ea Forerunner to clean living conditions on the road is this porta- ble bath-house with collapsible tubs and hot running water 48

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bed over Wyoming’s rugged topography, a stunt never before utilizing twenty-four horses. Of course, the truck won its venture the Automobile Driver accessories are coming lying dormant during war J. F. Conder’s automobile signal; with ruby and green lights, an arrow designating the direction Machines equipped with disk wheels can now use skid-chains with this attachment The wind-shield consists simply of two wings at- tached to the back of the front seats, which are ad- justable to any position A simple load meter entails a stick which touches the ground when the maximum load is installed, being sprung up out of the way when the truck is running 49 SPRING GUARD The straps prevent the end of the axle from moving backward, preserving steering control in casé of spring breakage An efficient worker is this porch-climbing truck designed for freight terminal work; it. turns around in a _ ten -foot circle HINGED FOOT. REST A comfortable foot-rest for the acceler- ator that relieves leg strain and the ““wabble” so detrimental to gas economy

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The patients are made ‘as comfortable as possible on their trip, lying down or sitting up as they feel inclined The Lunacy Limited HE Cook County department of public service of Illinois has built the first special car for the traveling insane, in order to shield them from contact with a curious public. The car, which has its own motive power for electric lines, is provided with all the latest comforts and con- veniences. down. be excited by street sights. There are berths for those who wish to lie The shades are usuallydrawn, so that patients will not A nurse is in constant attendance. Popular Science Monthly, Clean, neat, and comfortable is this car, ready for its brain- sick passengers They board the car in an out-of-the-way place where there are not likely to be passers-by Good-by Iceman; Here’s an Automatic Refrigerator HE gas refrigerator, entirely auto- matic in its operation, promises to work a revolution in household re- frigeration systems greater than any since machines were first successful in making artificial ice on a large scale. With the gas refrigerator the house- wife can regulate the temperature of her refrigerator to suit her own needs, make enough ice for household pur- poses, and at the same time save money. The gas-operated machine is so efficient that 140 cubic feet of gas, costing from ten to fifteen cents, produces refrigeration equal to AMNKONIA LIQUID FLOW PIPE that from a hundred pounds of ice. The gas-operated refrigerator works on the same principle as the large refrigerators and ice factories; that is, © liquid ammonia is turned into a gas, which expands, taking up enough heat to cool the pipes through which it As in ice factories, liquid ammonia is turned into a gas, which expands, cooling the pipes. There is no mechanism to get out of order, no moving parts or whirring wheels 50 passes. In this new machine, how- ever, the whole operation is reduced to a small scale, with the result that the domestic size machine in twenty-four hours gives refrigeration equivalent to the consumption of 150 pounds of ice. The machine consists of a tank called the generator, which contains an aqua-ammonia solution. A pipe leads to a coil in the condenser; the lower end of this coil is connected to a receiver. Another pipe leads from the bottom of the receiver to one end of an expansion coil. Heat is applied to the bottom of the generator from a gas-burner. This heat releases ammonia gas from the aqua-ammonia solu- tion. The gas passes into a water-cooled chamber in the upper end of the condenser, and is discharged in a liquid condi- tion. The liquid ammonia under pressure then passes into the expan- sion coil, where evaporation of am- monia gas from the liquid performs the cooling function. The spent ammonia gas passes back into the aqua-ammonia solution and is used again. The only attention needed is the lighting and extinction of the gas.

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how- xed to at the y-four ant to of ice. tank ntains pipe ; the dtoa m. the ond of om of urner. ia gas solu- nto a 1: the r, and condi- under 2xpan- . of am= rforms spent — 0. the - Loading the air- May, 1919 “Sg PFac aie ye * © pe Se i, SS, he. ee eee s. ae. Sas The engineer of the fast air freight is at his ‘post and ready to start. He’s an old-timer, and the run from Folke- stone in the very southeast corner of England to Ghent in Belgium—about 100 miles in an air line—is an easy one plane freight. Will the workers be known as the ’long- . skymen’s union? Nae Here’s a Floating Garage for Motor-Boats UT in the Detroit River is a float- J ing garage for motor-boats. Are you out of “gas”? Head for ‘“‘Marine Station No. 5” and you can buy what you want, just as you buy it on shore. The regulation type of pump is on It’s Off—the Airplane Freight! deck, while a hose of sufficient length is at hand to supply all comers. The oil- barge is an old one especially refitted for the purpose. The equipment in- cludes four 3,500-gallon gasoline-tanks, three At the air-ship freight-sheds. Packing must be done compactly for the flyng freight. Some day we'll be contrasting these hy pictures with the ha giant freight-plane passing along the air lanes, much as now we contrast pictures of the early steam trains with the Twentieth Cen- tury. Not long ago a New York depart- ment store made suburban deliveries by airplane, trying outas an advertising “stunt ” what-.may become an unno- ticed daily incident 1,000-gallon oil-tanks, and one 1,000- gallon kerosene-tank. The supply station is open and doing business twenty-four hours in the day, never leaving its anchorage unless navigation is closed. A gasoline service station anchored in the Detroit River; it carries 14,000 gallons of gas and 3,000 gallons of oil 51 Every appliance for the convenience of motor-boats is found on board |

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*familiar. and useful simile, but it remained for an English school- OY: to wonder what happens when the ‘Op ‘strikes in the bucket. He tried to. find out by causing drops to fall upon ’ carefully smoked glass, after which he could study the prints made pa drop upon the carbon. Some enty years later Professor A. M. Worthington = became interested in drops, andin 1894: under the title - “The Splash of a - Drop,” delivered _ an address: ‘setting forth his’ observa- tions. — This. was afterward printed by the Royal In- stitution. It -was certain that any changes that a drop under- goes . must be of exceedingly short duration. Hence |= a drop in the bucket” is a | The Story of a Splash “What happens when the drop falls in the bucket By H. E. Howe observations of each stage until he could accurately sketch what he had seen. Later on he had the satisfac- tion of being able to confirm his early work, using more modern photo- graphic apparatus and fast emulsions. The illustrations reproduced here are from a series of drawings, and illustrate the exercise a drop of As the drop spreads it forms distinct rays— sometimes as many as twenty-four (Fig. 9) Popular Science Mont . in stage seventeen we find twelve lobes, Surface tension checks the spread, © and then a rapid and powerful contrac. tion takes place, causing the mer. cury to rise in the center almost to the breaking-point, as in twenty-six, This sudden drawing in of the lobes causes droplets to become detached and marks the beginning of the re bound. At the end we may haye two circles of different-sized drops surrounding the remainder of the original drop, and the entire ge- ries of thirty stages takes place ' in a total time of about one twenti- eth of a second— an interval of one six hundredth of a second for each stage. At certain the first problem, as in most investi- gations, was that involved in. pro- Surface tension causes the gymnastic exer- cises that a drop goes through when it falls stages, such as numbers f ourteen, Forming pairs of fifteen, and six- lobes. Fig. 17, with| twelve pairs, is the climax of this stage teen, the mercury is sometimes coy- viding suitableap- paratus. Adrop of definite size was to be allowed to fall from a definite height in darkness, and any desired stage in the phenomenon illuminated by a spark of such exceed- ingly short duration that all other stages would remain unobserved and not blur the picture. Many Observations Necessary These conditions were eventually satisfied by providing two similar levers released simultaneously. by an electromagnet. From one lever the drop was allowed to fall from a small watch glass smoked to prevent wet- ting, and the other let fall a marble that struck. an adjust- able releasing mechanism, which in turn broke an electrical con- nection, causing a short spark near the spot where the drop struck. By regulating the re- lease mechanism, and therefore the distance through which the marble fell, intervals sepa- rated by very small fractions of a second could be secured. At the time the first experi- ments were made the photo- graphic plate was not suffi- ciently rapid to record the mercury takes when one .15 inch in diameter falls three inches upon a smooth glass plate. Time, One Twentieth of a Second Surface tension is responsible for the movements and patterns observed. The distinct rays shown in number nine are twenty-four in number, as determined by counting the droplets that squeeze off the end of these rays. Next, an annulus with a very thin area between center and rim is formed, followed by the rim forming pairs of lobes. . These are drawn together until ered with beaiti-. ful concentrit rings. The phenomenon depends upon four factors: 1. The size of the drop. 2. The height of the fall. 3. The surface tension of the liquid in question. 4. The viscosity of the liquid. The possibilities of this interesting study have by no means become ex- hausted. Study drops of ink or of milk: falling upon water, or indeed the phenomenon of large drops of water falling upon water, giving rise to the beautiful bubbles so often seen in a hard rain. Solids falling into liquids are another possibility. Value of Modern Photography Modern photography — re member that Professor Worth- ington did his work before 1894—ought to record unusual features. He used a Leyden jar spark for his photography, the duration of such a spark being probably less than ten millionths of a second. It would be interesting to determine whether our more recent methods are any more image, so that Professor Worth- ington found it necessary to make a very large number of The surface tension checks. the spread of the drop and causes the center to rise The rebound. Only one twentieth of a second intervened be- tween Figs. 1 and 30 satisfactory, so far as results are concerned, than the care ful work of a patient trained observer.

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Obes, read, \trac- mer- st to y-six. lobes ached ie Te- have drops the f the lrop, ire ge- hirty place ° me of wenti- ond— . al of iredth id for rtain oh . as irteen, 1 six- ercury 2S COV- reailti-. ntrit upon liquid | resting me ex- of milk ° ed the water to the on in a liquids graphy ry — Te Worth- before unusual Leyden graphy, a spark 1an ten ting to ir more 1y more ; results he care- trained May, 1919 Here’s a Bare- Back Rider of the Air Lieutenant Ballough fears the bucking airplane as little as a broncho-buster does a “‘bad’’ horse. But then, airplanes don’t really buck any more. Modern flying-machines always right themselves if they are high enough. Only on an inherently stable ma- chine is Lieutenant Bal- lough’s feat possible. Of course, the Lieutenant took good care that he did not throw the center of gravity from its correct position Although the Lieutenant takes many liberties with his airplane, he has to keep close to the machine’s center of gravity. If he were to venture too far from that center; all balance would be destroyed and something would happen quickly If he steps off it’s two thousand feet down; but he has learned to trust the stability of his machine. He can step out on a wing (not very far, to be sure) and walk forward and back- ward—something that was entirely unthinkable ten years ago +) Pietures © Keystone View Co ny

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Flying a Mile High, He Hears How the radio-telephone now links the airman with the earth By John HEN a swift-flying V of eleven monoplanes soared into the view of Colonels Reber and Culver at the 1910 Belmont Park Aviation Tour- nament, the same thought, oddly enough, came into both their minds and was expressed by Colonel Culver: “What a splendid thing it would be in battle if those eleven planes could be instantly commanded by their leading pilot! What could be done with the control of every’ evolution from the air or from the ground, and with each pilot receiv- . ing instructions from moment to moment!” It is easy even for civilians to see what this would mean. Directions given before the flights began, as conditions changed with the sud- denness of war-time needs, could be changed, and each flier could be told just what to do in a mass attack on the enemy. As the two colonels looked back to the wireless telegraph work that had already made it possible for pilots to report observations to ground stations miles away, they determined that this ideal of a voice-commanded squad- ron of airplanes should be realized. What Has Happened Strive In five years the telegraphic branch had been developed to a point at which airplane communication was demonstrated over one hundred and forty miles at. the flying school near San Diego. In another year it was possible to telegraph in both directions between airplanes in flight, without serious interference from the noises of wind and motor exhaust. Early in 1917 the wireless tele- phone was used to talk from the air to the ground, and in October of that year experimental radiophone outfits for squadron flying were taken to France for demonstration by Col- onel Culver. A year later Major-General William L. Kenly and Director John D. Ryan, in charge of the air program of the nation, announced that the _ voice- commanded squadron was a reality, and that, since the signing of the armistice had removed the need of secrecy, its effectiveness could be shown to the public. Demonstrations in Washington, at which President Wilson and Secretary Baker were present, banished the last doubts as to what had seemed an im- possible dream only six years before. Vincent The manufacture of a suitable helmet was only less dif- ficult than the of a j transmitter | production good How the complete radio-telephone transmitter looks on an airplane assembled ready for installation At one of these demonstrations the President, standing on the White House lawn, gave a command to dive. Immediately a swift de Haviland, flying overhead, nosed toward the earth. at increased speed until, at the words ‘Flatten out,” it turned into the horizontal and sped on in a great You Speak Popular Science Me hh / \ curve to obey the further instructions. _ from the ground. How can such a thing be done? How can the ear-pieces strapped to each aviator’s head, sheltered from the outside roar of motor and wind by a padded helmet, reproduce the very words spoken by the flight commander, whether he be seated in another airplane or at a distant. point on the ground? It seems aq marvelous thing, but is it really more wonderful than the act of sending a telephonic message by wire from New York to San Francisco? Magic of Wire Telephony In wire-line telephony we know that the vibratory sound-waves of the voice strike against the dia- phragm of a transmitter, causing this diaphragm to vibrate in 4 similar way. The mechanical vibrations compress and release a capsule of carbon granules fastened immediately behind the diaphragm, and the variations in pressure create variations in the resistance, which the granules oppose to the flow of an electric current through them. ’ The intensity of the constant stream Here is the com- plete radio - tele- phone equipment for a ‘‘two-place” airplane. The head- pieces and speaking sets are easily. picked out. From them wires lead to a switch-box. By turning a knob on this box the ob- server or pilot can cut out the outside world and talk with each other. From the switch-box the wires run‘into the large box at the top of the picture, which houses the trans- mitting and re- ceiving sets. The small box at the left is a “filter,”? which eliminates the noises that are caused by the wind- driven genera- tor shown below it

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“uctions: e done? pped to, ed from 1d wind luce the e flight » seated. distant. seems a. t really act of : by wire ancisco? hony ye know. vaves of the dia- causing te in a chanical . alease a fastened _phragm, re create e, which flow of h them. it stream May, 1919 ; enerated by a battery a = fad passing through the i ules, is thus varied in accord- pers with the voice _ vibrations. This fluctuating current is led along the line wires from the transmitter to the distant station, and there is “ad to a telephone receiver. ET aiver contains a diaphragm which is moved magnetically by the incoming currents, and which vibrates at a speed and intensity governed by the variations in the currents. Since these. current-vibrations are similar to those of the voice at the transmitter, the receiver-diaphragm vibrations that they produce are also similar. Conse- quently the receiver re- instead of merely varying the intens- ity of a stream of current passing out over wires to the receiver, the radio- transmitter varies the strength of a continuous stream of electromagnetic waves, these being radiated into space in all directions from an aerial wire. A portion of these waves necessarily reaches the distant receiver, and there is caught by a similar aerial wire in which the waves induce high-frequency varying currents. These currents are then led to the receiving apparatus, by which they are first converted and magnified, and then applied to a tele- phone instrument in which they re- produce the sounds spoken. Imagine a fleet of airplanes in which each is equipped with a complete radio-telephone transmitter and re- ceiver. The pilot of the commanding airship can control his squadron in- stantaneously by his spoken orders; the group can act in unison for attack or defence, and movements of enemy airplanes or forces detected by any observer can be immediately described to all the others. Some of the Difficulties Overcome The manufacture of a suitable hel- met that would exclude the terrific explosions of the 400 -horsepower Liberty motors (which are creates sound-waves similar to those generated by the voice at the sending station, and the listener hears a re- production of the words as they are spoken into the transmitter. Although a number of simultaneous operations are involved, the action is evidently not at all complicated. Analogous to Wire Transmission For transmitting the voice by wireless an entirely analogous set of conditions exists. The main and Testing the vacuum tubes or bulbs of the instruments which detect electromagnetic oscillations coming from any radio station, amplifying them so they can be heard obvious difference is that ra there are line-wires to con- 3 duct the continuous stream of voice-carrying electric current from the trans- mitter to the receiver. Some other way of con- veying the voice-controlled vibrations must therefore be found; and in radio- telephony this part of the communication sys- tem is based upon the properties of electromag- netic waves in the so-called ether of space. Just as a candle radiates light-waves in all directions, so a suit- able radio-generator will radiate streams of elec- tromagnetic waves to dis- tant receivers in any direc- tion. Having at hand such effective carrier-waves to transport signals from point to point through the air, whether on the earth’s surface or above it, all that remains in order to trans- mit speech by wireless is to devise suitable appara- tus for the sending and receiving stations. __ The wireless transmitter, like that of the wire tele- Phone, contains a dia- phragm and a capsule of carbon granules. However, The bomblike object is a double-voltage generator; it is driven by the propeller at its forward end, the propeller acting much as does a child’s pin-wheel This amplifier, with its high vacuum tube, increases the sound of the signals from five toten times invariably used without muffling-chambers) was only less difficult than the pro- duction of a good trans- mitter. When one considers how the ordinary telephone picks up the noises of passing trolley cars or trucks, it is easy to appreciate the amount of work that was required to make a micro- phone which was marvel- ously sensitive to the human voice and yet scarcely af- fected by the thunder of the motors or the rushing of the wind. Another knotty problem was the arrangement of the aerial wires so that they would not trail far behind the airplane and become entangled when loops or dives were performed, or when the other airplanes of the flying squadron. ap- proached. This was solved by the use of short un- weighted wires dragging from the wing-tips, rather than the long single cable that was first utilized, and which suspended a lead weight some three hun- dred feet below and behind the airship. Future of the Radio- Telephone It is difficult to foresee the future of airplane radio- telephony, for its greatest value is doubtless in ¢on- nection with group flying. But the day of the com- mercial airplaneseems dawning. When groupsof airplanes travel together from city to city, their pas- sengers will surely appre- When the cap is removed you get a glimpse of the mechanism of the wind-driven gen- erator, showing the voltage-regulating tube ciate the radio- telephone. . : 7 | ; i}

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Of Their Bones Are Buttons ' The hair on pigs’ backs grows in silky waves and makes excellent stuffing for mat- tresses. But a 50-lb. bale of pigs’ hair is so large that its traveling expenses are heavy. So when hair is shipped it travels as rope. It is wound up tightly before it starts, and is fluffed out again after it arrives. There is just as much hair in this rope as there is in the pile behind it yj ——eeas These are guts. They are cut and stretched into long strings and: then fastened on pegs ‘ to dry. *Tis. on guts like these that Mischa Elman makes a living : ' : —they are to be turned Each machine gnaws into violin strings.. The on a bone and bites list of things in every- off buttons. As the ‘ day use. made. from buttons dribble out, * the-antestines of -ani- girls catch them in |) > ta ., mals is a long,one, small trays, and when Y a Pa : j You will ‘see it graphi- the trays are full they ‘ »\ 1 “cally~portrayed’ in’ the dump the buttons into | oa ' large picture on the big boxes on the floor page opposite this Pigs’ -hair,is very hard to curl, but ‘curling is necessary to The bone trimmings on cows’ heads are turned into bon make it fluffy enough for stuffing: So, instead of using a trimmings for ladies’ heads—in other words, horns, ere“- ~ ‘ curling-iron, the hair-dressers spin it into long ropes, wet turned into hairpins. . Here are some bone hairpins aoe it, and then. loop it-around the horns of cows to.’ dry getting a final polish before going out into the world ~

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ha Baz BE. ae Here are the guts again —this time made into surgical ligatures for binding arte- ries and veins during opera- tions. They are kept free from dampness in test - tubes Ten bales of roped pigs’ hair take up just about as much room as one bale of fluffed pigs’ hair. If you don’t be- lieve it, go back to the upper left-hand corner of page 56 When a cow, pig, or lamb goes to market, its meat is turned into beef, pork, or mutton. What happens to its hoof, hide, horn, and other meatless parts? Start with the top row of this picture. There you will see some of the products that are made from their respective hides; second row, from their muscles; below that, from their vitals, and lastly, from their bones. By the time they have reached the last row, all three animals look like “the ghosts of Dead-Pig Farm” After the hide is ripped off an animal’s back, it is given a series of lime baths, going from one to another. over. a hide reel.. When it comes from the last one it is hairless—the hairs all came out in the wash i i | J \ hi t ! > | ("

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PERFORATED ° BAFFLE-PLATE SECTIONS ‘AR-TIGHT JOINTS A cut-away view of the muffler, showing the per- forated baffie-plates that are an integral part of it OUTLET—— Here’s a Muffler that Can’t Possibly Blow Up S a general thing, automobile mufflers begin to rattle when the inside baffle-plates work loose from the outer shell. Troubles of this nature are eliminated in the new type of muffler shown in the illustration above. This is accomplished by flanging the outer circumference so that each flange of the baffle-plate overlaps the section next to it, and thus makes the baffie-plate an integral part of the shell. By this type of construction any chance of the baffle-plates becoming loose is eliminated and the shell strengthened so that they will not blow up. The plates have openings cut in them as shown, so that the exhaust gases are made to travel in an irregular path and in this way hold them back to permit of their gradual expansion. The headers or end plates of the muffler are made of malleable iron, and are held together by tie-rods running clear through from one to the other. nan SUPPLY Popular Science Mont ly = One tank within another, which au- tomatically holds its supply of gaso- line until needed, is made possible by the use of a three - way valve ‘DRAIN TOA = CARBURETOR. * This Gasoline-Tank Has a Fool- Proof Reserve HE gasoline reserve shown above is fool-proof because the tank is divided into two parts by a transverse plate which gives two supplies, only one of which can be drawn from at one time. This is made possible by the use of a three-way valve in the bottom of the tank in the reserve | supply. Filling the tank automatically fills both supplies, but in draining the tank one supply always remains full. When the engine stops for lack of fuel, as when one supply is exhausted, the valve is turned and the other supply used to reach a gasoline station. If the main supply is used first, the valve is open to the pipe leading to that end of the tank, to the carbureter, and to the drain, which is closed. When the supply is exhausted, the valve is turned so that the Teserve supply is open and the drain-cock closed. An Adjustable Body Support for Trucks Its sub-frame fits trucks of all sizes a standard type of body to NTIL the adjustable type of sub- frame shown herewith was worked out by a Columbus, (Ohio) body-maker, the fitting of one standard type of body to trucks of different frame widths and lengths was done in a more or less hit-or-miss method. In this body all of the adjustments are made in a special sub-frame mounted on longitudinal wood sills directly on top of the truck chassis frame. There are four adjustments. The first adjustment is for any varia- tion in the width of the truck frame, and is made by the use of two clamps on each cross-member of the body sub- frame. These clamps are attached to the truck sill and bolted to the cross- member at varying corresponding A——————— “rf eee eee ZZ LLLLLLALLLLALE LLLASS ELLA ADJUSTMENT XZ how the three adjustments are Showing : obtained for width, length, and depth = ——————————SS SS SS — ————— rd widths by passing the bolts through horizontal slots cut in the cross- member. The second adjustment is for the longitudinal position, and is secured by a series of three holes drilled in a horizontal line in the hinge casting ADJUSTABLE CLAMPS ADJUSTABLE BOLTS SUB- FRAME ADJUSTMENT A body that may be attached to any truck uses a standardized adjustable sub-frame 58 when an end-dumping body is desired. The third adjustment is for the ° depth of the truck frame and wood © sill. This is secured by sets of two ~ flat metal pieces with hooked tops, ’~ which fit into the bottom flange of the I-beam body sub-frame. The bottom’ of each piece is slotted so that the crosswise bolt holding the two pieces together can be moved up or down. The fourth and last adjustment is ' % = ha for the width of the hinge member and is made by means of an ordi- nary turnbuckle.

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‘ause plate rawh of a serve © ut in When ly is (0 the ind to isted, open esired. «© rr the © wood * of two - tops, ~ of the yottom ' at the up or nent is dth of — rember ade by n ordi- buckle. May, 1919 This Motor-Truck Has No Grease-Cups A new system of oiling .WNERS of motor-trucks ‘will tell you that the next worst failing in the average freight vehicle driver, after speeding, is the dif- ficulty of getting him to turn up the grease-cups. Grease-cups are generally placed on the front and rear spring hangers and shackles, propeller-shaft bearings, and steering-gear mechanism. To reach the grease-cups on the propeller-shaft the driver must crawl under the truck. But some drivers become so careless that they neglect to fill or turn up regularly even the cupson the spring hangers, which are easy to get at. If these are not well lubricated the springs, of course, do not function properly. To overcome these difficulties, C. T. Myers, a consulting truck engineer of Avenel, N. J., has evolved a new system of chassis oiling called magazine lubrication. Oil is used instead of grease, and it is kept in a reservoir or magazine chamber from which it is fed through capillary action to the parts to be oiled by wicks. CnaAssis How the oil is fed to the parts that need lubrication a HEAVY OIL.’ —— — 4. WICK BUSHING SPRING A motor-truck without grease-cups, which employs the magazine oiling system, is an improvement over present methods Even if the oil is dirty, the dirt is not fed to the bearing to be lubricated, because the wicks will not carry it. The oil feeds only when the truck is in motion, and any seepage drops down on the spring leaves, preventing rust. Controlling the Speed Automatically How the starting and lighting equipment is adapted for this purpose RECENT modification of the usual starting and lighting equip- ment of gasoline engines used on tractors is its adaptation to engine speed control and governing without the addition of delicate mechanisms. It comprises a six-volt storage battery, a starting motor, a control-box containing the lighting and ignition switch, as well as the rheostat for the governor-genera- tor. The latter has built integral with it the ignition system—induction coil, primary circuit breaker, and distributor. The governor-generator proper is the usual form of four-pole, shunt- wound machine. The field frame, however, instead of be- ing rigidly attached to acts to turn the frame in a direction opposite to that of the armature ro- tation. A dash-pot retards any sudden movement of the field frame. When the armature is caused to rotate in the field frame, a current is generated therein, part of which flows through the fields and energizes them. The magnetism of the fields, acting on the armature, creates a magnetic drag that turns the field frame in the direction of the armature rotation and compresses the spiral spring.. The turning effort imparted to the field frame can be effected either by altering the resistance in thefield circuit, and consequently the current, or by a change in the speed of the armature. The engine speed can be controlled by the rheostat in the control-box. When the rheostat is on the first point, all the resistance is cut out of the field circuit and the current in the fields will be at maximum. The drag on the armature then being greatest will turn the fields through a large are and thus close the carburetor throttle, giving a low speed. As the controller is advanced from point to point, resistance is added in the field circuit and the magnetic drag is lessened. The spiral spring then acts to turn the fields back the engine base, is sup- ported at both ends in- side its housing on trun- nions. This permits the field frame to turn through an are of thirty degrees, but in no way interferes with the arma- ture rotation. The field frame has ‘attached to it a lever‘connected to the carburetor valve by a link,-so that any move- ment of the frame is communicated to the valve. A spiral spring is pro- |. CONTROL BOX. STORAGE BATTERY STARTING MOTOR COMMUTATOR AND BRush GOVERNOR GENERATOR and open the throttle, increasing the speed. The governing of the engine speed is based on the second method of changing the drag; namely, an increase of armature speed will in- crease thedrag. Afterany engine speed is obtained by adjusting the con- troller it will be main- tained, for should the engine speed up due to a decrease in the load the increased drag be- tween the fields and the =| armature willturnthefor- vided at one end of the generator housing, which A lighting and starting equipment that embodies also a governor for automatic engine speed control 59 mer to close the throttle and reduce the speed.

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Building a Bridge Under Water Neither a tunnel nor a bridge, yet both in one, paradoxical as it sounds OR years the commercial need of EF a railway crossing over, under, or through the British Channel has been recognized, as the POPULAR ScIENCE MONTHLY pointed out in its issue of December, 1918. Always the bugaboo of an invasion of England has risen to throw cold Channel water on these projects. Today a railway link between the two Allies is deemed absolutely essential. Had there been such a crossing it would have undoubt- edly facilitated By F. W. Fitzpatrick Where there is very deep water, such as an ocean inlet, to cross, a body 250 or more feet deep, of course the diffi- culties multiply. Long spindle-legged concrete or stone anchors or “‘support- ing piers” have to be built unless the tube is to rest upon the bottom. In the latter case the approach grades are bored under the bottom, and in the Popular Science M a The canal at this point cuts q long strip of sandy shoal that woulg have been an admirable and myeh needed freight terminal. But the authorities were frightened by jt, novelty. There is a crossing there now, an aerial bridge that took every bit of ingenuity. I possessed to get approved by the War Department, and that affords only a crossing for vehicles and pedestrians. The scheme is the handling of troops and sup- plies during the war. In England _ there is a Com- mission already _ at work studying plans, finances, etc., for the pro- ject. So far, a tunnel bored under the bottom of the Channel is the one plan receiving most serious attention, chiefly because there is a fear that any other form of structure may be blown up ‘by a mine or depth bomb. ideal for ~ the crossing from San Francisco to Oakland, where in the seven miles of water there is no greater depth than seventy- five feet. San Francisco's Needs There hasbeen a good deal of talk of a bridge, then of a tunnel, It is generally recognized that something must be done to relieve the railroad iso- - lation that now Years ago twenty-odd schemes were submitted. One much _ talked of was a trackway laid on the bottom, on which track a sort of platform could be hauled back and forth across the Channel. In turn, a train, run from the ground track upon this moving platform, could be whisked across on the surface of the water, without interfering in any way with the rest of navigation. This year I have submitted to the Commission a project for ef- fecting the crossing by means of a “subaqueous bridge’? — neither a tunnel nor a bridge, and yet both in one, paradoxical as that may seem. It Is No Longer in the Experimental Stage There are several examples of river crossings in this country, one in France, one in England, and one in Russia, and plans have been drawn up for many such crossings. The scheme is no longer in the ex- perimental stage. ““My subaqueous bridge crossing consists merely in lowering a previously built tube into place, either right on the bottom of the waterway or raised above the bottom on piers,” says Mr. Fitzpatrick, the inventor of this system former case the construction of such piers a hundred feet or so high and all under water is an undertaking of con- siderable magnitude. But in shallow water this subaqueous bridge is ideal. One of the First Projects Was for Duluth One of the first projects of this kind seriously considered was the narrow crossing of the canal at Duluth. grips San Fran- cisco and handi- caps its terminal railway business. About seven years ago the newspapers and local engineers were quite en- thusiastic about this subaqueous bridge crossing, but politics and lack of funds and the war prevented the plan from being actually realized. ' Just now there is a movement afoot to get the authorities to doing some thing in that crossing matter. It is important, necessary, and would be of tremendous benefit to the city of San Francisco. At intervals there will be lighthouse-like vent-towers projecting out of the water © 60 the proper place, and sunk into position on the piers. With the ends of the tube

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ow, an bit. of proved d that jehicles heme ig r ° the - from cisco to where seven water is no depth venty- ncisco's -ds hasbeen deal of . bridge, 1 tunnel, ‘enerally ed that ng must to relieve road iso- - hat now an Fran- d handi- terminal business.. wspapers juite en- yus bridge : of funds ylan from ent afoot ng some- er. It is nuld be of . city of the water 10. of the tube May, 1919 Divested of all technical details and terms, my ‘“‘sub- aqueous bridge”’ crossing consists merely in low- ering a previously built tube into place, either right on the bottom of the waterway or raised above the bottom on piers. It is the simplest, the most effective, the most cheaply maintained and least expensive water crossing. Built Like Con- crete Ships My plans are for a concrete tube, made in sec- tions ashore, as we build concrete location is automatic. Tighten one line of bolts and the juncture is as solid and water-tight as any part of the structure. At the ends of the tunnel or subaque- ous bridge the ap- proaches lead through open cuts or troughs exactly 2s one would ex- pect for the regu- lar bored tunnel under a waterway bottom. Some twenty years ago definite plans and esti- mates were made for four crossings, railway, street- car, and_ street traffic, near the ships. Sections about three hun- dred feet long are the more easily handled. They are square, large enough for a double track, provision being made for drain and ventilating pipes, electric wires, etc. Each section has a temporary bulkhead at the ends and is launched as you would:a ship, and towed to the point where it is to be sunk in a trench previously dredged or on piers built in place. To sink the tube section the bulk- heads are knocked out. The water fills the tube, and it sinks, directed by divers, into its proper place. The ends are fastened to the other sections. Another and another section is low- ered. When all are in place the water is pumped out, the connec- tions perfected, tracks laid, lights, ventilation, That Mr. Fitzpatrick’s scheme is not impracticable is shown by this picture ° of the process carried out in building the portion of the New York subway that goes underneath the Harlem River. built of steel instead of concrete; but they were sunk, as Mr. Fitzpatrick advocates, in a carefully prepared trench. ‘This was in the year 1913 becomes too great for two tracks, another double-track tube is laid alongside the first, and another and another later on, as needed. Thus the “‘subaqueous bridge” can develop with- out in any way disturbing the first tube or its traffic. How the Sections Are Joined Together The joints in these tubes are so de- vised that when the two sections are butted together the easing into exact and drainage installed. Your “subaqueous”’ bridge” is complete and ready for operation— the cheapest and best water crossing ever de- vised, one not subject to winds and storms like a bridge, nor disturbed by currents or tides, nor painfully bored under- ground. If the traffic In this case the sections were Cortlandt Street ferry line into New York. The crossing would have required nine anchorages, and was estimated to cost $3,000,000. Careful plans are being made at present for the Dover-Calais Channel crossing. What will be the cost? It is too early to state definitely, but we have gone far enough to be sure that the cost™would not be in excess of forty per cent of what a regular bored tunnel under the Channel would be. The tube idea was at first opposed by engineers. Now it is regarded as fundamentally correct. It was thus that the New York subway was built under the Harlem River. At a conference of railroad men_ before whom I was advocating this tube crossing for a certain river here, the The really troublesome problem would be to keep the tube from floating off from the anchor piers. ings Mr. Fitzpatrick shows how to prevent such a possibility aid in ventilation. The concrete tubes are to be built in sections ashore, towed to sections temporarily closed for transit, the tubes could be towed like large scows 61 In these two draw- chief engineer of one of our greatest systems was loud in his oppo- sition. Finally, as a clincher, he suggested that the piers necessary ‘to support the tube would have to be won- derfully strong, and that the load in the tube would be so great as to produce a sag in the middle of each section. It was only after much bantering on the part of his colleagues,.and the illustration of trying to «eep a closed glass tube down in a glass of water, that it dawned upon his expert mind that the piers were not for support, but for anchorage. The really trouble- some problem would be to keep the tube down in place and pre- vent it from floating up off its anchor piers.

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set CR SON BOI AD SORE AIRES IES a . means boring a hole. Don’t Let Stumps Clutter Your Land They can be pulled or blown out REE-STUMPS are just so much dead wood taking up valuable space and yielding nothing in return. The sooner they are uprooted the better. -Many kinds of stump-pullers are used in different places. In Michigan a tripod stump-puller is used exclusively. With it four men and four horses can uproot seventy- nine stumps a day. But it can be operated in only a few positions. There are two types of hand stump- pullers. © One of these jerks the stump up from thé side. The other lifts the tree‘up, like the tripod puller; but, unlike the tripod type; it can be oper- ated-in almost any position. But stumps can also be blown out without harm to anything in the neighborhood. ‘The charge should be placed in the wood itself to obtain the best results, which An elec- tric drill is used for this. A turpentine company op- erating in the long-leaf pine section of the South uses the electrical drill with great success. The machinery includes a small horizontal gasoline engine and a dynamo, which can be transported on wagons or skids The operator jerks the handle of the stump-puller, which tightens a rope round a tree and a line attached to the stump To blow up a stum~, first drill a charge hole six inches below ground with an electric drill drawn by a team. Two electric drills using 1%-in. augers are driven by this apparatus. Holes are bored into the stumps at points from six to ten inches below the surface. These holes penetrate the stumps to such a depth that the charge can be placed at or near the center of the tap-root. Bang! No more stump. The tripod puller grasps the stump like a pair of forceps and lifts it out of the ground Popular Science Me al In Case of Shipwreck a Pillow-Slip MAN attired in regulation uniform, with a rifleand cartride belt, appears at Palm Beach. Holding a pillow-case in his hand, he wades oy from the shore. He dips the pilloy case into the water, whirls it about } ye head, and thus fills it with air. . Than he twists the mouth of the slip. Tig he has a life-preserver, inflated ané ready for use. — He places his rifle across the pillow. slip and propels himself through : water at a fair speed merely by kick in the usual swimmer fashion. supporting qualities of this improvi I Having moistened a pillow-slip, he. inflates it by whirling it around, and then uses it for a life-preservér ° ~~ @B&errrnnwT wv prerommaec preserver buoy up the man and hig gun, when at rest, without swimming movements. After floating about for fifteen minutes, the man comes ashore and turns over his outfit to a totally inexperienced young man, who dupli- a cates the feat with perfect ease. For simplicity and quick use the pillow-slip commends itself as @ possible means of saving life. Any’ camping party has a supply of pil- lows on which to rest the weary head, and a few experiments such as this would be of great interest and possibly of great use. A com- pany of soldiers might ford a river in this manner. Only a second. is Te-. quired to fill the slip with air, and preparations are all complete. a =r © of as ee TLE 1 BES The horses turn the capstan, which tightens the rope attached to the stump, increasing the pull until the stump is torn up

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~ May, 1919 ‘Radium Turns Darkness into Light ~ HE market price of ra- dium is$120,000 a gram, and a gram is less than one five hundredth part of a pound. Then how can peo- ple afford radium-dabbed watches, clocks, and house numbers? Because radium is marvelously _ self-lumi- nous, and a few micrograms (one of which is a millionth part of a gram) mixed with zine sulphide crystals will paint your house number and keep it luminous for years. That is because zinc sulphide, being itself phosphorescent, is sensitive to radium rays. Strange as it may seem, the more radium used the This 57 has nothing to ao i 11 known varieties. : s gr - meso ausnter Stasi shorter the luminous life of nated so it can be read'at night the compound. if You Must Have Something Hot / OON a bottle found in a gentleman’s hip pocket will ear | land him in jail as quickly as a gun will. How, then, ; Bo no A g can you warm your chilled blood when traveling? Slip a he can like the one shown below in your side pocket. Then, cree: if you are searched and the worthy law enforcer pulls out oh the can, he will find that the lid is really a saucer and the l hig canacup. Inside he will find a lamp, a box full of spoons, ming matches, tea, and a strainer. t te The lamp (a spirit one!) has an unfolding base, and a cap ia a to prevent the escape of the spirit odor. The lamp is placed tally within a stand, which likewise comes out of the cup. Then ples ae the cup (its collapsible handle extended) is filled with water x and the tea is made. Of course you don’t have to drink e thé tea; you might fix os bouillon, or even hot Any lemonade. f pil- weary Before you start on a It will be most useful when such long trip, slip a can you get that faint feeling teseik like this in your pocket about four in the afternoon com- ver in is Te-. , and When the kit is opened, you find The can becomes first a saucepan and a complete outfit for making tea later a cup from which you drink 63 J The acrobat is always a prime favorite in the East, where dexterity is traditionally admired for its own sake The Acrobatic Japanese in Siam N the far East, land of street fairs, the Japanese juggler is a familiar fig- ure. Even so simple a feat as that shown above, which seems to be little more than the manipulation of a giant swing, is holding the absorbed interest of the Siamese and Malays. The per- formers will pass the hat for stray cop- pers when their stunt is over, and; no matter how poor or wretched the audi- ence may be; enough will be forth-com- ing to compensate them for their work. Now and then a traveling troupe will set up a canvas curtain, station a man with a drum outside the entrance to attract attention, and collect a small admission fee in advance. But when it comes to the star act, the trapeze performer ascends his trapeze high in the air in full sight of everybody. The operators inside surely would not begrudge those less well off than them- selves the benefit of a free entertain- ment. Thus reasons the Oriental mind.

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enables the lineman to stand on the eg Uneaten pis beet excoriation aa Popular Science Mom You Can Hammer Nail into This Concrete ONCRETE came into us as a building materia} be- cause it could be easily molded into shape. In this it is far superior to. * brick, and wood, and eogtg \ _no more. But when the Making Life a Little Safer for the Lineman HAT look like bandages on the wires on the sky-scraping pole at the right are not put there for the protection of the wires, but as an insurance against electro- cution for the workmen. ‘The danger of working among wires carrying high-voltage currents is one of the line- becomes very hard—gl. man’s joy-killers, and no de- Py most brittle. If you drive vice has’ yet been invented ||" “Sitaeipee—peeenen . : “3 F>-—_]| a nail into concrete, jt that will enable him with im-. its : crumbles. punity to indulge in capers Now comes a new eon. among wires carrying cur- . crete into which nails may rents with voltages of 33,000 be hammered. It is a new and up. — building material which has The bandage-like protector- been used with great sue. shield reduces the risk to a cess in the Parliament Build. minimum and enables a careful ing at Ottawa, Canada. It man.to go. about. his .work in is prepared and sacked like comparative safety. = “ concrete, mixed with sand and The shield, made of heavily insu- ff ae water in the same manner, and is lated wraps fastened about the wires, ~ i r ~~ similarly applied, shoveled, tamped, : =a and smoothed. The time required for setting is about the same, and so is its ‘molded concrete dries it cross-pieces, or even on the network of wires, without the haunting fear Quick death flows through these wires strength. It is lighter and smoother that an incautious movement will beneath the hands and feet of the line- than concrete, and it can be laid with bring him in contact with a death- TAP and contact with an unprotected —_—_ out forms on a sloping surface. dealing current. more oan a neepa all to kingdom Its smoothness makes it useful for This simple precaution renders. a come. The bandage-lixe shields are flooring. Sometimes it is given simply formerly hazardous job comparatively _ the lineman’s life-savers on the wires a high polish, and sometimes it safe. stained and grained to resemble wood, If neither of these is desired, hard-wood flooring or linoleum can be tacked down on it. A layer of this concrete inserted in the cement or hollow tile around windows, doors, and near the base makes it easy for the carpenters to fasten the framework and base The upper slab is board in place. One of the novel uses in the Parliament the new concrete Age Building is for‘ the ceiling in the large chamber. This th its t ‘ . . Ae ter foe § a concrete was selected because it can be readily plastered ed to resemble to the metal lathing. wood: the lower Just after one floor of the Parliament Building was right slab is the finished and the next floor begun, the new floor’s plans were same_ concrete highly polished; changed. The workmen tore down the work they had done, and the left slab and all the scaffolding, dropping them all on the newly has a square of finished floor and trampling on it with their hob-nailed hard-wood flooring W/ nailed to its safene. boots. Yet the floor was not even scratched. ,Mr. Viens, director of the public works laboratory for testing material at Ottawa, is the discoverer of this marvelous material. The new concrete is prepared and sacked like concrete, mixed with sand This strange composition does and water inthe same fashion, and when applied is shoveled into place, tamped, not break or crumble when nails and smoothed. The time required for setting is about the same as concrete or screws are driven into it 64

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The cross is in the die, ready to be stamped. Two hundred and fifty tons pressure must be applied ten times be- fore it comes out again limousines, although we own more airplanes than we have use for just now. The rea- son is lack of landing-places. An airplane travels so swiftly that it needs large, flat ground areas in which to start and land. There are few of these in our large cities and between them. That is one reason why attempts to fly from New York to Chicago have been unsuccessful, and is the main reason why many airplanes are not being used. London has its airplane field near by, and so has Paris. Although one dar- ing Frenchman recently landed on a roof, that stunt 1s too dangerous to become fashionable. - The comforts of the mod- The D.S.C.—Our Medal for Valor International Film Service The. Distinguished Ser- vice Cross is the American equivalent for the French Croix de Guerre and the English Victoria Cross. It was born during the Great War, just after our men went to France to fight. The crosses are made in the Philadelphia mint Bonar Law Has His Own Airplane In which he flies from London to Paris HIS is Bonar Law’s own special airplane in which he flies from London to Paris when he feels the need years ago. thereof. Our statesmen, however, must he content with Below it is shown ready to move into the room ‘shown at the left, where finishers wil! trim off the edges and make it fit for service Neither of the men sitting in the cabin is Bonar Law. Most likely they are photographers who like to be photographed 65 ern airplane contrast sharply with the airplane of ten Do you remember the old type of plane in which the pilot sat in a seat which jutted out from the plane and was poised pre- cariously over nothing? An observer had to sit along- side of him and grow dizzy every time he looked down. The modern plane is built much:like a limousine, with a driver’s seat up front and a comfortable cabin behind. Take, for example, this plane of Bonar Law’ss He climbs up a ladder, drops through a hole in the lid, and finds himself in an elec- trically heated and lighted cabin containing two leather seats, a table, and a small baggage-room. He might take another person with him, dictate letters, or dis- cuss the question of the hour during his brief, smooth flight. ; a] 4 | i |

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creat eee ee ARE RE a a a SRR GR a ae th RRR EE: A : Plan yeaa ne ae gr pale tnarttie’ tem menage cite real se Which Is the Right Glass for Your Skylight? Popular Science M. onthly ; KYLIGHTS offer an ideal method of illumination if the proper kind of glass is used. Ordinary window- glass or plate-glass is not suitable for obtaining the best results, because it does not diffuse the light passing through it. Glass will diffuse the light only when one or both of its surfaces are rough. ‘One of the illustrations above shows a cross-section of a THE airplane of to-day is sur- Wanted: The Eyes of a Bird prisingly like a bird. But the creature has one striking defect—it is nearly blind. Put the observer where he can be the eyes of the craft, and you must place the propeller where it will revolve through the very space occupied by. the fuselage. That means cutting the airplane body in two and holding the parts together by nothing more than the:thin spine that forms the axis of the propeller. Sight is gained at the expense of strength. And if we try to gain strength through outside framing inclos- ing the propeller and ‘connected with some part of the machine, the clean, efficient outline of the airplane is broken. Pull, Pull ee HEY are getting their first lesson in crew pulling,.and from the wild:way some of them are waving their oars it’s the first time they ever rowed at all. The ‘Navy is ever _ confrented with this job of making real sea- men out of green sailors, and so it has built rowing-tanks like the one shown here at all large naval stations. The tank and the two rows of seats are made of concrete. The instructor stands at the tank’s edge, and shouts orders to the hard- working crew, who can’t get away from the sound of his voice no matter.how hard they pull. Up and-down the aisle between the rows runs another instruc- tor, shouting through a megaphone at erring individuals. Light passing through pebbled glass is uniformly dif- fused by the irregular unevennesses of the surface By placing the propeller back of the observer’s seat the man-made bird is no longer blind, but the airplane body is cut in two and. loses strength They learn how to row in a tub Glass with one plane and smooth and one ribbed surface re- fracts the light in a regular pattern and also causes diffusion piece of rough glass commonly called ‘“‘pebbled.” The light rays are broken up by the irregular curves of the sur- faces, and the light becomes uniformly diffused. The other picture shows the effect produced by light passing through a plate of glass with one smooth and one ribbed surface, The rays are refracted by the ribs, and form a regular pat- tern which is clearly noticeable in the picture. On the other hand, it might be thought that in the French airplane shown here the propeller is so hidden in the cleft fuselage that it must lose power. That is a mistaken idea, since it is only the outer ends of the blades that really drive the machine. An American inventor, Gal- laudet, has made a rather better job of the problem by halving ~ the fuselage nearer the tail, where it is narrower and needs no bracing, and placing the pro- peller directly behind the wings. But the best solution may come from the optician. He may be able to invent an artificial ‘“‘eye” placed in front. It is possible that the periscope may be pet- fected for this purpose. er

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The 2 sur- other ‘ough rface, r pat- might rench peller selage hat is only 3 that Gal- better alving tail, e pro- wings. come ay be ‘6 eye” »ssible e per- May, 1919 It Tells the Aviator if He’s Upside Down | } K HEN an aviator gets into a fog, his position is perilous. Since he can’t see the ground he doesn’t know whether he is on an even keel or not. He has even been known to fly upside down for a short time and not know it. Dr. James Pentz, of New York, has invented a compass that not only tells the aviator his north and south, but also tells him whether he is upside down. The compass-card rests freely on a surface of kerosene inclosed in a glass globe. Liquid will not stand on its head for any length of time, but will settle down in the position gravity meant it to. In his first attempt Dr. Pentz at- tached the compass-card to the globe, which deprived it of the necessary free- dom. He complained of this to his sympathetic wife, who pulled a hair- pin from her hair, drove it into a cork, and floated it, thus helping to solve the problem. Trapped in the Bowels of the HERE are mines in war and mines in peace, and so the very micro- phones and geophones that located German diggers with great accuracy last year are now holding down peace jobs in American coal-mines. By means of these instruments sounds can be heard and located to a depth of one hundred and twenty feet. The micro- phone records air waves, and the geophone earth waves. These two instruments are very much alike in the matter of construc- tion. The receivers that fit over the ears of the listeners are very much like the ordinary telephone receivers in an electric circuit. .Two diaphragms rest on the ground. The smallest change When the miner is trapped :far-below the surface of the earth, he need only hammer on the wall for the listeners above to locate him The compass is fastened in front of the pilot, where it takes the place of three other instruments: it gives direction, the points of the compass, and the angle at which the airplane may be flying in sound waves, such as that produced by the hammering of a miner trapped in the earth below, alters the resistance in the circuit and hence the current. This causes the sound to be reproduced in the receivers. | Heretofore if an explosion occurred in a mine, entombing-the miners, rescue work was done blindly. Of course, the searchers were familiar with every sec- tion of the mine, and so could guess as to where the men would barricade themselves in to escape the gases in the mine and to preserve the pre- cious air. Often the miners were entombed for days, as in the case of the Cherry mine disaster in 1907. Sometimes they 67 Airplanes Spy on Outlaw Cotton-Growers IRPLANES are now aiding agri- culture. They have not yet taken to pulling plows, but they are playing an important part in the unending battle against the devastating pink bollworm that has been trying to in- vade the United States from Mexico. In southern Texas, where the boll- worm first crossed the border, there are cottonless zones maintained as barriers against the advance of the worm. Most of the cotton-growers have recog- = nized the wisdom of the law creating the zones, but a few who have become what is known as “outlaw’’ planters in- sist upon growing cotton in the for- bidden area. _Much of the country is heavily tim- bered, roads are few and bad, and it was very hard to find these hidden fields. But with army aviators lent by the War Department the Depart- ment of Agriculture recently carried on a campaign which discovered seven fields in the forbidden district. Earth were brought out in time, at other times too late. ._It was simply a ques- tion of sheer luck.’ If the searchers happened to strike the right spot the miners were saved; if not, they suffocated. Now a miner need only hammer at the wall, and the listeners stationed above will know just where he is and direct the searchers to him. The pic- tures shown below were taken when the instruments were tested. The man hammering the wall with an iron bar played miner, and the other two men listened. The miner had barely stood up and brushed the dust from his knees when his searchers found him. One man has a microphone and the other a geophone, both of which record and locate the mimer’s tapping ae ae EN

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res asa siat ee eee com See -coer ee Voyaging to Europe in an Airship The skyscraper hitching-tower of the future By Carl Dienstbach ECAUSE the giant Zeppelin made B no brilliant showing in its raids on England, the average man is apt to dismiss it with a wave of the hand, saying, “It’s a failure.” When he thinks of air transportation he thinks of airplanes. It would profit him to read the re- port of Admiral Jellicoe on the great naval -battle off Jutland, in which the Zeppelin showed how effective it can be as a naval scout, and to study the testimony recently given by Admiral Sims of our own navy before a Con- gressional Committee, pleading for the construction of titanic Zeppelins in this country. It would also profit that average man to ponder the fact that Great Britain now has a fleet of Zeppe- lins, and that one of them, in all likeli- hood, will be sent across the ocean to prove the practicability of transatlantic trips through the air. The truth is that the great rigid dirigibles, to the development of which Count von Zeppelin devoted the last twenty years of his life, are the Mauretanias and Leviathans of the air. When it comes to voyaging from New York to London with something like the comfort and luxury of a fast ocean steamship, the business man of the future is more likely to buy his ticket for a transatlantic Zeppelin than for a transatlantic seaplane. Zeppelin Difficult to Handle Let us admit at once that it is more difficult to handle a Zeppelin, both on the ground and in the air,:than a giant flying-machine. Half:a:dozen men at most are required to swing a huge Caproni or a Handley-Page airplane on the ground so that it heads in the proper direction. But when a Zeppe- lin comes down to be berthed in its 700-foot shed, a highly trained ground crew of from one hundred to two hun- dred men, each man knowing exactly what he has to do, must take the huge envelope in charge. More Zeppelins have been wrecked on the ground than in the air. A fabric composed of a wonderful lacelike aluminum framing cannot withstand terrific collisions with the ground. And so, Zeppelin after Zeppelin was wrecked until a special ground-hand- ling technique was evolved. _ Now, a real ship of th air should no more require a shed than does a ship of the sea. It should be weather-proof. Indeed, this was Count von Zeppelin’s main idea. In a sense, it is just as ridiculous to run a dirigible into a shed as it would be to house the Mauretania whenever she touches port. Problem Solved by British But what of the problem of docking this huge dirigible of the near future? There will be no problem—at least, not in the present sense. A shed for airships should be required only for repairs. Before Europe was embroiled in the bloodiest of all conflicts the British showed us a way out. They built towers of steel and tethered their small non-rigid dirigibles to them by the nose. Thus moored at a height from the ground so great that they could not be dashed against the ground, the vessels swung like flags in the wind. The idea may be carried out on a more grandiose scale when the trans- atlantic, weather-proof Zeppelin of the future arrives. Imagine every important American city fringed with titanic steel towers that resemble the famous Eiffel Tower of Paris—hitching-posts to which Zep- pelins are tied. They form integral parts of the steel framing of the sky- scrapers that constitute their lower portions; for in the populous city of the future the utmost use must be made of every square inch of ground. You go up, of course, in an elevator. You step out on a broad platform that surrounds the tower. A gang-plank runs from the platform to the moored Zeppelin, stretching away for eight hundred or even a thousand feet. At the top of.the tower is a curious semi-globular, vertical cup, gilded so that it flashes in the sun. Into this cup the nose of the Zeppelin is received and lashed to the tower. Platform Swings with the Airship The cup on top of the tower and the platform from which the gang-plank runs to the ship constitute a structure independent of the tower. The cup and the platform revolve together. You can see at once what this means. As the Zeppelin, with its nose poked into the cup, is swung by the wind, just as an anchored ship swings with the current in a river, the platform swings with it.- Even though the craft may be in the act of swinging in response to a passing gust, you step on board by way of the gang-plank just as you would climb the stairs lowered down the sides of a ship anchored in a stream. An aeronautical engineer, familiar 68 fi, | 1 i) ‘\ fa.| =| m1 \ Popular Science Monthly with the vagaries of gas, realizes that it is not enough to hitch a Zeppelin to a high tower and leave the craft to itself, Gas and ballast must be ‘controlled at anchor as well as in the air. But that , is no difficult matter. Water ballast can be pumped through pipes wher- ever it may be needed, and gas can be conveyed in asimilar manner. Hence, we must expect to find pumps on the towers so that an anchored vessel may be trimmed. Indeed, the pumps can be automatic. As for pipes, a part of the aluminum framing of the envelope may be used without aading an ounce of weight to the vessel. When It Reaches New York But what of currents of wind? They are almost negligible at the top of a lofty tower. But if they should oc- casionally make themselves manifest, and that so rapidly that it is im- possible to shift ballast or gas quickly enough, then the vessel’s own elevating rudders can be used. Oh, the crew must always be on duty, you argue? Not at all. The elevating rudders can be operated automatically. A mer- cury level will: switch electric servo- motors on or off. What a sight it will be when a trans- atlantic Zeppelin arrives at New York and heads for its tower, a long, beauti- fully modeled, slim cylinder. Down she slides. See, she comes up slowly into the lee of the tower and against the wind. Thus she uses the wind as a kind of brake. She must fight it with her own engines, and fight it she does. By nicely regulating his own speed, the commander literally crawls up to the tower. Ah, a line has been thrown out and caught by the Zeppelin. The rest is easy. Curiously seamanlike, too, will be the airship’s departure for Europe. . She casts off. She drifts away with the wind, and sinks a little with the stern . down (a kind of ‘“‘tail slide” in airplane parlance), until the propellers reverse the motion past the tower. Then she goes up, up, up into the air, and away to distant London, where -her passen- | gers will breakfast day after tomorrow.

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May, 1919 = Here she is in her shed—a giant British Zeppelin. Will the rigid dirigible of the future be thus housed whenever she finishes a voyage? We doubt it. It is very likely that in the future sheds will be used only for purposes of overhauling and repairing. This ship is the R-33, the largest of British Zeppelins, which has fuel capacity and engine power enough to cross the Atlantic Just like the bridge of an ocean steamer, you say. And you are right. All the navi- gating instruments and ap- pliances of the Mauretania are found on board a Zeppelin, with a few more (such as height indicators) that the captain of the Mauretania never needs The. engines are inclosed.in separate cars, as this picture shows. When helium instead of highly explosive hydrogen is used to inflate the bags in the envelope above, it will be possible to put the engines right in the hull and thus give the craft cleaner lines

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3 ee rity NY BETWEEN SHIP AND MAST » mm MOORING GEAR. ROTATING MAST- nNEAD WINDING GEAR. FOR. SHIP WINDING GEAR. OR LIFT WINDING GEAR. FOR LIFT London to New York by Air: Across the Atlantic [Mr. Dienstbach wrote the preceding arti- cle for POPULAR SCIENCE MONTHLY before we received the following contribution from our British correspondent. Since the pro- ject of Messrs. Vickers is soon to be realized, we thought it well to present their -construc- tion of a Zeppelin mooring-tower side by side with Mr. Dienstbach’s. fact, Mr. Dienstbach proposed the mooring- tower fully fifteen years ago, when Zeppelin after Zeppelin was wrecked on the ground in high winds.—Editor.]} Eas: BRITAIN has been mak- ing plans to institute a regular transatlantic airship passenger service between London and New York. Soon you will book your pas- As a matter of sage to London by air- liner and cut your time of crossing in half. Seasick- ness will be a thing unknown. You have ocean-liner comforts. When you are hungry you will walk into a well supplied restaurant. Luxurious berths invite you at bedtime. The designers of these giant dirigi- bles are Messrs. Vickers, Ltd., the well known British armament-makers. The air-liner proposed will have a length of eight hundred feet and a diameter of one hundred feet. It will surpass any German Zeppelin in size as well as in speed. The hull outline will be a perfect continuous streamline 70 By C. A. Oldroyd, Correspondent of the shape, with no external projections save the six cars carrying the propelling machinery and the stabilizing and steering planes near the tail of the ship. It will carry one hundred pas- sengers and a crew of nineteen. The passenger accommodation will be on top of the airship, for here no vibration due to the engines will be felt. The crew will be accommodated in the keel of the ship. This internal keel runs the whole length of the ship, and an elevator con- nects the keel with the passengers’

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odated whole or con- engers’ Fd iti 4 of li). \ cal ; age? \ \ egst i? ' af | in Two Days in an 800-Foot British Zeppelin Popular Science Monthly in Great Britain quarters. A shelter-deck, fire-proof smoking-room, and observation saloon will be. provided. Six engines, giving a total propelling horsepower of 3,500, are provided in the six cars to drive the ship at a speed of seventy-five miles an hour. But building the airship alone is only half the problem. A shed capable of housing,two giant airships costs about two million dollars, while the complete air-liner would cost less than the shed. Recognizing that the shed will have to be eliminated if commercial airships are to become a fact, Messrs. Vickers set to work and perfected a mooring-gear for airships. By this means the ship can be moored to a mooring-mast and ride out the severest gales in perfect safety. This mast allows the ship to swing in every direction while held firmly. The ship can be released instantane- ously when desired. The mast is about one hundred and fifty feet high. Four strong steel cables are secured to the masthead at one end and to deep concrete foundations at the other. The mast itself is of square cross- section, and an elevator travels inside. 71 Gas, water, oil, and gasoline supply- pipes are also carried inside the mast. When the elevator reaches the re- volving top of the mooring-mast the passengers enter the ship through the bow immediately below the mooring- gear. A flexible, covered corridor, similar to the connection between Pullman cars, connects ship and mast. A second elevator takes the passen- gers from the keel to the top of the ship, while a small runway conveys food, mail,and cargo~to ‘the store- rooms. The passenger rate from London to New York is £115 ($575), while mails cost only fifteen cents an ounce.

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- SSS ee oan artes ARC ye ene a ROMA onan als aiwat te mete mbiomagn ee! ee - — , ete ss = tee A inline inn ene Sr Popular Science Monthly — 4 he trees of Oregon pay taxes to the State and support four fifths of the inhabitants. ._Both the State and the people have felt most grateful, but knew not how to express their. appreciation. Trees are hard things to thank. The Portland Chamber of Commerce at last decided on a “monument—not a marble United States is in Oregon, which State tree on a marble base with a tender inscription on its -bark, but’ an immense log’ cabin made of the trees themselves. It contains more than a million feet of lumber, and’it is the largest log cabin in existence. There. are This Carpenter Mae: No Arms or Legs ‘Ta most tragic case of war is that in which a healthy, whole man en- lists, fights, is wounded, and is sent back maimed— an arm gone, a Jeg gone, sometimes both; sometimes all. The world’s sympathy does not repay him for his ability to do things. If he persists he will be able to work, no matter how badly maimed; for look at the man above. With arms and legs gone, he is yet a first-class carpenter. With one arm stump and one leg-stump he holds the saw, and with the other arm he holds the work. a a iss Ada hn Oregon’s Log-Cabin Monument to Its Trees five huge tree pillars at the front entrance and many more around at the back door. Its great size can be appreciated by com- paring it with the small man leaning against one of the pillars in the picture on the right above. One fifth of the standing timber in the country. What’s a German Helmet Worth? lf you didn’t get a chance to go over and get one your- self or didn’t have a son or a friend to pick up-a Ger- man top-piece for you, there is still a last opportunity left to win one while fighting for liberty and the Republic. You won’t run the slightest risk, to be sure, nor have the glory of the fighting man. You'll have to fire a golden bullet in the Liberty Loan campaign, where every $10,000 bond purchaser will get a German helmet, one of the common or inverted-kettle variety, or perhaps a dressy Pickelhaube. The instalment of bond-boosting Hun hats in our picture number 86,000. The Liberty Loan captains are hoping that they wi!! have to ship more of the ‘‘tin hats’ from France. The soldiers will tell you that it’s a lot easier to buy one here than it was to go Fritz- hunting in Europe. © international Film stands fourth in timber production in this If Oregon’s merchantable timber, repre- senting more than 403,000,000 feet, were sawed into lumber, it would require 430 years’ work for 30 sawmills, each sawing 100,000 feet of lumber every working day of the year, and 336,111 trains of 60 cars each, making a continuous train of - lumber, reaching nearly seven times around the earth at the equator. The-value of this is not less than $680,000,000, and when manufae- tured is equivalent to bringing into the State $6,822,500,000. wddida f _ BEAST tak Pree ee —an oe |e Learning to Play by Animal ANGING ear-splitting discords out of twelve notes on a toy piano will be an unknown joy to the children of the future, for the child’s piano is fast turning into an ‘‘educa- tional toy.” Well-meaning educators have decided to use it and pictures of animals to teach children scales and _ to help them pick out such tunes as educators think proper. A’ different animal is painted on ‘each key; and in the music book the tunes are interpreted in terms of these animals.

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in this , Tepre- t, were. ire 430 sawing ing day 60 cars train of - n times ‘quator, ss than anufac- ng into ¢ Play 7 il splitting twelve ino will y to the ure, for is fast “educa- lucators e it and to teach and to it such s think imal is 2y; and- ok the eted in mals. May, 1919 The Japanese Way of Mailing Mail JAPANESE mail-box looks like A a combined fire-hydrant and water-heater, and it is painted bright red.» Without a doubt it 1s the most startling and substantial thing in that dainty country. But this is fitting, for mail is considered a serious matter by the Japanese government. When the kimonoed gentleman in the picture below reaches the mail-box, he will turn the dial until the slot in it.coincides with a slot in the box. He slips the letter in the slot and the dial swings back where it belongs. — When the postman comes along he will take the mail through the door at the base of the column. What London Is Doing with Its German Cannon LL the Krupp blood in this cannon is boiling at the undignified posi- tion forced upon it. In the first place it is in London, and in the second place it is turned almost upside down with its trail high in air. The same thing has happened to many other German guns, for cannon trails—particularly German ones—make excellent perches from which to view parades, and there are many parades in London today. Besides these other indignities, this German trail is forced to look at returning victorious soldiers whom, not so long ago, its other end tried to kill. Unfortunately, the American mer- chant marine has been too busy with other things to kring over any German cannon. The Bees Love Him TUNG? No, honey! Sounds like slang, but it is an exact statement of fact, since E. R. Root, the man who appears to be washing his face in bees, says that when bees are kept busy making honey they are too happy to sting anyone. Mr. Root is a bee expert who is known wherever hives and honey grow. To prove his peace pact with the bees he wears a hatful of them when he lectures on ‘how doth the—’ He always says that in California, at least, the bee doth very nicely, thank you, be- cause there flowers—the makings of honey —bloom all the year round, and the bee is kept busier, and therefore happier, than anywhere else. Bringing in a Whale of a Whale ANEW whaling station was opened at Monterey, Cal., and the whaler was called Her- cules. When Hercules spotted his first whale he went after it enthusiastically, confident that, like the god he was named for, he would conquer. But the whale put up a strong fight— it dragged Hercules seaward from early morn till late at night. However, after six harpoons had been fired into the whale it gave up and was towed to shore. It proved to be a giant of its kind, sixty feet long, sixty tons heavy—a sperm whale valued at $5,000. If ordinary fishing is too tame for you, why not try whaling? You never know, when you go after a whale, whether you will get him or he will get you. If he is stronger you will play Jonah; if you and your boat are, you will be several thousand dollars richer. © International kiim

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aa stipaisinn poco bai Peter ey ci mame aoa Rn we oS ER FER a scm can " Popular Science- Mo 3 | Housekeeping Made Easy A shoe-shining kit that utilizes the cover of its container as a polisher. The box holds the cleaning materials compactly and is easily stowed away in a drawer A combination dressing-stool and step- ladder for the bath-room has steps covered with rubber, while the wood is _ finished in a pleasing white enamel Hanging ten skirts, this adjustable folding rack-is made to fit the inside of a closet door. When the skirts are in place the rack folds against the door, occupying very little space Pray Lit This medicine - spoon has a spring cover eas- ily lifted by pressure of the thumb when in use A velvet-covered pho- nograph-record cleaner which enters into the record’s tiny grooves An ingenious dust-cloth, painted to resemble a ‘“‘mammy’s face,” is a mitt that fits the hand; the cleaning is done by ‘the woolly hair The revolving thief-proof milk-container has as many locked compartments as there are tenants, and is attached to the dumb-waiter First as a handsome library table and then as.a comfortable bed, this contrivance economizes space in apartment-houses Perforations in the hose permit the pump operated by the - faucet to suck the water from the tub into the washstand

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May, 1919 The sliding jaw of this milling vise is adjusted to the work by clamping the bearing in place The teeth or “grippers’’ auto- matically adjust themselves to any shape set into the vise Used as lead screws on lathes for the United States Government, these 55-ft. forgings were easily and safely carried to their destination by a five-ton truck Indicating calipers are some- thing that fills a long-felt want. It also combines both a rule and a magnifier A handle that stays put is the boast.of this vise. It may be moved to any position without varying the jaws Presses that form and stamp automobile and railroad car parts into shape are ponderous machines, as may be seen from this picture le es The amateur carpenter’s tools Any boy can operate this r always be ready if he In welding high-speed steel to ordinary steel a saving new type of band-saw; it * utilizes cigar - boxes thus is effected by using a shank of lower-priced material is practically fool-proof 75

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SSS Then, if a man is badly hurt, flying back Pei with him in a stretcher or a_ bed ARRYING the wounded from the field to a hospital C by means of an airplane has proved so successful that the plan of transporting the hospital to the wounded has also been considered. Compact units of moderate size have been designed to give more complete first aid to the wounded. rf The progress made so far gives rise to even more com- : | plete plans and possibilities for the future. The units 1 will include X-ray sets. Minute compass needles of di special design will locate the bits of shell or exploding il boiler. A surgeon and radiologist, in addition to the pilot, i will man the machine in its flights to the scene of action. i Even if there should be no more war, the airplane ; doctor of the future will have his work to perform, and a wonderful work it will iF | be. Specialists will use the airplane to answer urgent calls coming , on ee ea aepaaes HNO LAAN HNN ONAHWHABNHHNHONHN HH EET Bringing the Hospital to the Wounded by Air Popular Science Me SS i from long distances. it Power for X-Ray | from Motor The motor supplies power to a small dy- namo that generates “ the necessary current 1 for the X-ray appa- Bi: ratus. Lightness and ‘ compactness are the essential characteris- tics, so that the ap- paratus may be of a portable nature. sa When a machine has arrived on the scene, the injured man (ecmnrmennncanncanerseennnapananenseaniisiiaiianiiiasuisisissisiiiiiiiyismmemiiastainess sm The .worst cases are carried back to the hospital in a comfort- able bed held in its place in the airplane by rubber ropes Out of small drawers— some of them in the airplane’s sides—come a compact instrument stand, an instrument- box, and the neces- sary electric sterilizer This is a regular hospital stretcher which fits in its place in the airplane An X-ray table and outfit which gets its power from the airplane motor make first-aid surgery possible may be taken into the X-ray compartment and examined at ence without even removing clothing. If it seems undesira- ble to move the patient into the machine, the instruments can be removed and ‘used outside or in any near-by hospital or other building. The machine, | meanwhile, may return” for The motor also heats water for the doctor’s additional supplies or more collapsible wash-stand. No detail has been surgeons. overlooked in this wonderful air hospital 76 RARAARIE =e: 5 -Srhgsce Fchecis int amie anzeiabeaon ae The physician’s radius of action will be very greatly increased. He will be able to visit rural districts hither- to inaccessible. The country physician of general practice will be enabled to call into consultation the specialist living twenty or forty miles away. The Doctor's Gig of the Future Carrying the mail. has already proved successful. Why not the transporta- tion of physicians? ‘The ~ medical field is broadening beyond” the dreams of a few years ago. Soon the night air of the quiet country ham- ‘let will resound to the splutter of the airplane doctor’s motor as he traverses the skies on his way to a patient.

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‘blade or chopped a root. It. was uncanny to anyone May, 1919 This Farm-Hand Never Tires or Asks for Pay Sit on the porch and watch the synmotor work T was not alive, ap- parently, and no hu- man being seemed to be concealed about it, and yet the thing. was seen cultivating a ten-acre farm in New Jersey. Down the rows of corn it went all alone, and never bruised a who had never beheld such a sight before, and even to some who had. It worked nights, too. Dimly outlined in the white moonlight, it could be seen threading its way with almost. human in- telligence and with mathe- matical precision, while the farmer slept peace- fully in his near-by man- sion and dreamed of wav- ing corn-tassels. Around and around the field the thing moved, around a center which it continually approached. The corn are made by - had been planted in a spiral formation about a tall post capped with a circular drum or cask. Close inspection reveals a thin wire extend- ing to a central drum, around which the wire winds itself as the work of cultivating pro- ceeds. That explains the spiral movement. The wire shortens itself by the same amount each trip around, and is used for steering the SAFETY SWITCH The furrows between the rows of dwarf corn plows automatically steered 40 LBS TENSION —, =e 48° 66LBS ANCHORAGE 043" STEERING WiRE la STEERING POLE FLANGED STEERING ys FRICTIONLESS STEERING WHEEL PIVOT implements for cultivating the land. Plowing, hoe- ing, harrowing, and the many other operations are performed in the spiral path as well as in the straight course. A gang- bar for the attachment of the implements may be 's used so that several rows may be cultivated at the same time. When the synmotor is utilized on a large scale, the farm is divided into convenient ten-acre circles, each section being planted and cultivated separately. Any vacant spaces between adjacent circles can be utilized for fruit trees, buildings, or the like. For that matter, the interven- ing spaces can also be cultivated by merely dis- engaging the steering wire and utilizing the tractor in the customary manner. For intensive farming and overlapping seasons, the accuracy of the synmotor in following a given track is of great advantage. The machine does not dis- turb the small plants, and it can work very closely to the rows. The working tools are spaced the exact distance between rows and do not swerve from the spiral course. Strawberries, peas and other vegetables can adius of . greatly be able 3 hither- country practice -all into pecialist ty miles g of try ham- r of the Taverses — patient. machine. Yes, it is a machine, after all. ~———p}+Jo-crrcwveomaunns he cultivated with the synmotor, The wire, being perfectly tempered, cannot es rere With such a machine as this, the laziest stretch, and an electro-coated surface pro- oS} man on earth can sit in the shade and fan ro it from rust. Its oe is ce 15" ii ies. &. ad himself while gasoline does his work. . VIBRATION - DAMPENING than two pounds; yet a pull of six hundred eae] eer pounds is required to break it. The machine is a narrow tractor of special make, and it is called a “synmotor.’’ The engine is a compact but very efficient gasoline type of about four horsepower. To the framework can be attached any of the usual TENSION SPRING Showing the works of the synmotor This is the synmotor, the farming machine that does its work without an attend- ant; when it isn’t cultivating the farm it can be connected to a churn to make butter 77 On the big drum the steering wire is wound, thus drawing the cultivator ever closer to the center

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HE circular star map for May forms an interesting illustration — for an outline of the origin and the value of the constellation groupings. These groups varyconsiderably The long- drawn-out constellation of Hydra lies side by side with the small, regular, compact groups of Corvus, Crater,Antlia,andCanis ~ Minor. The great con- stellations of Hercules, Ophiuchus, and Virgo are astriking contrast in shape and size. to the constellations of Lyra and Corona Borealis. The longer one spends trying to fit the old mythologi- cal figures upon the star groups of their respective constella- tions, the more he is ready to believe the statement that the an- cient peoples of the East were practical as- tronomers. Orion and the Great Bear seem almost possible, but tracing the out- lines of a crab in Cancer or a giant in Hercules is quite be- yond most people. Ophiuchus, the Serpent-Bearer It is perhaps interesting to note that Ophiuchus was supposed to be a serpent- bearer, holding a writhing snake, part of which appeared on either side of him. This accounts for the constellation of Serpens These are the paths of totality for all the total solar eclipses which will be visible in North America within the next fifty years and Popular Science Me Finding Your Way Among the May Stars With the help of the ancient peoples of the East, who were practical astronomers By Ernest A. Hodgson, of the Dominion Astronomical Observatory being in two parts. Lyra represented a purpose in the early ages of astronomy, byt iyre; Corona Borealis, a crown; Bootes, a confusion soon crept in, and no two atlages hunter with his hunting dogs—Canes gave the figures exactly the same. Theng Venatici; while Corvus was supposed to fresh start was made. The constellations indicate a raven; Crater,a cup; Sextans,a were retained, but the stars were designated sextant; and Antlia, an air-pump. by the letters of the Greek alphabet. Gen. These mythological figures served a good _ erally speaking, the brightest star was sup. posed to be Alpha, the next Beta, and go NOZISOH Higdon on. In some constellations these letters ~ ——— <= were insufficient, so the letters a, b, ¢, ete,, were then assigned in order. When they too failed, the numbers 1, 2, 3, ‘etc., wereused. In the meantime some stars had received def- nite names, as Castor and Pollux, Betelgeuse, Sirius, Vega, etc. The simple vaming of the star was in their case sufficient, The others were desig. nated by the letter and the constellation name. New Stars Have Only Numbers The arrival of the telescope soon made this method too un- wieldy to name all the stars now visi- ble. So the names that had become fixed in use were re tained, but all new stars are simply re ferred to by their num- ber in the _ catalogue, which gives their precise location. Thus the naming of all new stars nowadays is quite independent. of the ancient constellation groups. The profes- sional astrono- mer has no use for them any longer, since he is able to set on any res NOZIHOH LSvq WEST HORIZON The Star Map for May The map represents the appearance of the sky at the times listed below. It is specifi- cally arranged for the latitude of New York, 40° N., but it is practicable for ten degrees on either side of this latitude.

eS T - April 7, midnight Ib 7 “ 15, 11:30 P. M.

23, 11 “ 30,10:30 “ May 8, 10 “ “" 15,9:30 “

“ce 23, 9 iti o Saale: June 7,8 = aaa <7 22. 7 “ce July * y . 30 sg On May 28 the Moon crosses the ecliptic at a point already occupied by the Sun.

The magnitudes are indicated on the map by stars of various kinds as follows: 0, open The result is a solar ‘eclipse. It will not be visible in North America. It start off the western coast of South America

center; 1, eight points; 2, six points; 3, five points; 4, four points; 5 is indicated by a single point. All time in Eastern Standard at sunrise, cross the continent, the Atlantic Ocean, and Africa, ending at sunset off the

. (not summer). eastern coast of Africa some five hours later

78

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my, but 0 atlases Then a ellations signated t. Gen- was sup- + and go ; letters » C, ete,, When s 1, 2,3, neantime ved defi- stor and , Sirius, > simple star was sufficient, re desig- he letter stellation rs Have Jumbers val of the oon made d too un- name all now vVisi- 1e names become were re- all new nply re eir num- catalogue, r precise e naming wadays is it. of the tellation 1e profes- strono- no use for ny longer, he is able set on ly res he ecliptic y the Sun. It will not It th America he Atlantic set off ‘the hours later May, 1919 _ must confine his attention to an ex- quired star by simply looking up its right ascension and declination in his catalogues. So, as the constellation boundaries were not required for precise astronomical pur- poses, they have never been precisely located: why run a survey line in a desert? All that is necessary, 1n putting in such boundaries in an atlas, is to so trace them in that the few thousand stars that are named with respect to the constellations shall be in their proper places. "> ‘Phe'constellations, however, enableama- teurs and those who observe without in- struments to make a report of any object they may discover by referring it to the near-by stars of a constellation group. Novae are very interesting objects, and astronomers are very anxious to get a chance to observe them at the very beginning of their appearance, before they have reached their maxi- mum. But the professional astrono- mer, peering through his telescope or attending to his photographic plate, tremely small section of the sky, so that it is usually his telephone rather than his telescope that first notifies him of the ad- vent of one of these celestial visitors. All such discoveries are, on this continent, reported to Harvard, and forwarded from there to the observatories by telegraph. In the case of the last great Nova in Aquila, it is interesting to note the large numbers of amateurs who independently discovered this new star and reported it to Harvard or to -Greenwich, enabling those provided with the necessary equipment to begin observa- tions at once. How to Find the May Planets AY will be favored with an unusually brilliant display of planets during the early evening hours. The _ three brightest, Jupiter, Saturn, and Venus, will all appear as evening stars, setting soon after the sun. In the early days of the month, and again toward the end, a cres- cent moon will add its beauty to the evening sky. During the early Cut out a disk of cardboard the exact size of the outer circle. From it cut out a section as indicated by the broken circular lines. On this disk mark the hours (Arabic numerals at edge), A. M., P. M., North, East, West, and Zenith. Run a glass-headed push-pin through the center of the disk, pinning it to the center of the map. To see the section of sky visible at any time on any but cannot be seen without optical aid. Note the rapid apparent motion of Jupiter this month as compared with the previous months of this year. The moon was new on April 30, at 0 h. 30 m. A.M. It reaches first quarter on the 6th at6h.34m.pP.M. Itis full on the 14th at 8h. 01 m.P.M. May 22 at 5h. 04 m. —— a ee an - VV Rim 6G ULP OR S¢ MERCURy / es date, turn the disk until the required hour on the disk is oppo- site the required date onthe chart line of the “‘mean Sun.” To see when any celestial body rises, sets, or reaches the meridian on any date, turn the disk so that the position of the body for that date is in the required position with respect to the hori- zons. Read off the hour opposite the position of the mean Sun for that date. The diskin useis shown below. P. M. is the time of last quarter, and it be- comes new again on May 29 at 8 h. 12 m. A.M. The centers of the circles show the moon’s position at 9 P. M. on the date given. The moon avoids the earth’s shadow at full moon and so is not eclipsed. On May 28-9, however, it crosses the ecliptic at a point already occupied by the part of the month, too, the bright stars, Sirius, Procyon, Castor and Pollux, Regulus, Capella, and the bright constellation Orion, will all be visible to the west just after sunset. By the end Orion and Sirius will be too near the sun to be seen. _ Jupiter and Saturn are in con- Junction on the 25th, and the folowing conjunctions with the moon occur on the dates noted: Venus on the 2d, Jupiter on the 3d, Saturn on the 7th, and a second conjunction of Jupiter onthe 31st. All these occur when: the’-moon is new or nearly so. Mars will not be visible, being too near the sun. It is in con- junction with the sun on the 9th. Mercury is west of the sun, and so rises before it as a morning star. It reaches its sun and so eclipses it. This eclipse will not be visible in North America. The eclipse in May is total. It begins off the western coast of South America at the time of their sunrise, ending when the people on the east coast of Africa see it at their time of sunset, some five hours later. The POPULAR SCIENCE MONTHLY is publish- ing every month an ar- ticle like this by Mr. Hodgson. If you feel that these articles can be made more helpful, write to the editor. And if there are any questions that you would like to ask about greatest elongation, 26° 36’ west, on May 5. Uranus and Neptune are shown in position, Illustrating how to use the planet map according to the directions printed above 79 stars, send them along.

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scents hs ates paca seach sa Ae eeen renee “ sell, — . a ee ee Sen een ene ee ors ooeaaparnetaae eeaamenatraneaimampamremstenmsmmmmmmerd SE aRanctGe, citenchess acs’ sheat-siar ceeamepsnsdliiameceaeeteesanamaa ied Popular Science Me | ' ~ A Typewriter that Writes in | Electric Letters A HUGE electric bulletin-board atop a newspaper build. ing in a mid-Western city flashes the latest news, device is operated by a typewriter. The bulletins are on the machine in the usual way, while contacts underneath a the keys control the apparatus that fiashes the correspond- ing letters to the roof. As each key is struck, the corre- sponding letter appears in electric lights in its proper pogi- tion on the big board. All the letters remain in position until the bulletin is completed. They are left standing a short while, and then the operator puts them out by pressing one key. : The sign itself lights up on both sides. Each side is \ divided into sixty units, arranged in three rows. Each unit contains an arrangement of twenty-one electric lights, Various combinations of these lights form any letter or numeral, as well as other characters. Selection of the units is done automatically as the writing proceeds. This is made possible by an extra platen on the typewriter. In this platen are sixty silver plugs, arranged to correspond with the sixty units on the sign. A stylus rides over these plugs as the ma- chine is operated, thus giving the desired connections, Since the operator cannot see the result_ of. his work from where he sits, a pilot- board is placed directly before him. This board has three rows of green-light bulbs, corresponding to the three rows of units. When he strikes a letter with the stylus resting on a certain plug on the platen, the corre. sponding letter appears on the display above, and auto- matically this causes the green light in the position corresponding to the unit and plug to burn. § The sign lights up on both sides. Each side is divided into sixty units, arranged in three rows, twenty-one lights to a unit. Various combinations of these. lights form any letter or number Bulletins are typed on the typewriter in the usual way, while contacts underneath the keys control the apparatus _which flashes the corre- sponding letters to the roof How Those Neat Little Coin Rolls Are Made HERE is a new way of wrapping coins in those neat little packages that the banks supply. It does away with the necessity of holding the pile of coins in a vertical position, which is awkward and results in poor wrapping. The coins rest on parallel rollers spaced slightly apart, but are held between two cylinders of wood upon the wrapper. The accompanying picture makes this clear. By exerting a slight pressure on the coins or on the rollers the pile may be rotated and the wrapper adjusted. One edge of the paper is gummed to make the package more secure. When the package has assumed the form described, it is removed with the end blocks still protruding and acting as stoppers. The package is placed in a vertical position resting on one of the blocks, after which the upper block is removed and the end of the wrapper folded inward in the usual manner. The stack is then reversed and the process repeated at the other end. The wrapping is now complete. Different sets of the cylindrical blocks must be ready at hand for use with the different sizes of coins, for the diame- ters of the blocks must be the same as the coins. Grooves in the end blocks permit air circulation and make the removal easy. Without these grooves the attempted removal of an end block would create a partial vacuum e within the package and tend to disarrange the pile. It is just such a simple expedient as this groove that often makes the difference between a good and & poor device. Snakes Take a Mean Advantage of the War NAKE bite caused 23,918 deaths in British India in 1917, nearly 300 more than in 1916. There were 2,176 persons killed by wild animals, 102 less than in 1916. Tigers got 1,009; leopards 339; wolves and bears, 280; elephants and hyenas, 89. Of the 456 set down to The coins are wrapped by turn- ing the stack while the end cylinders hold the coins together 80 pig, and 199 to crocodiles. “other animals,” 89 are assigned t0. LEE OPW ARGE TEM Ros ETE TT aa PG

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build. The typed neath spond- corre- T posi- osition anding out by side is ch unit B lights. tter or writing 1 on the inged to lus rides the ma- as giving ions. r cannot 1is work , a pilot- directly yoard has een-light ig to the . When with the a certain the corre. ypears on and auto- uses the. . position the unit . ready at he diame- Grooves make the rttempted 1 vacuum rrange the expedient nakes the od and 3 ~ Mean ne War ed 23,918 1 India in e than in 6 persons ss than in pards 339; hants and ; down to ssigned to May, 1919 }| oo STEEL CURTAIN ~ 8) =" 6e-506R-———— | \ If you wish to get low insurance rates, you should protect your elevator with a door like this, which rolls down automatically when fire reaches it ID you ever see a door or windowthat would shut itself in case a fire started in theroom? If you did not, look at the accompanying three pictures. They show an ordinary door, an elevator door, and a window that are the latest things in modern fireproof warehouse construction. They work on the same principle as the water-sprinkler, which gushes out its water as soon as the temperature is sufficient to melt a lead fuse in the water-nozzle. These pictures were taken in a Fort Worth, Texas, warehouse that has the Windows Planned to Trap and Outwit Fire In case of fire, this window closes auto- matically, shutting out the air without which no fire can burn and Doors that lowest fire insurance rate in the whole State because every window, door, and elevator-shaft shuts itself, confining any fire to the room in which it starts. The window-sash is made of steel and is pivoted at the sides at points below the middle, so that the window tends to shut itself when open, but is restrained from doing so by a small chain fastened to the bottom of the sash frame, then led through an eye at INCLINED / :) CORD TRACK FUSE wee. ae WEIGHT/ This door, mounted on rollers, is held open by a weight and a chain containing a fuse; in a fire the fuse melts, closing the door the top and finally fastened to a catch A on the window- re sill. A lead fuse, so made that it will melt at a cer- tain temperature, is hooked to the chain at the point of attachment to the bottom of the win- dow. As soon as the heat of the fire melts the fuse, the chain pulls away from the window and it slams shut, cutting off the air without which no fire can burn for want of oxygen. While the window is closing itself, the door leading to the next room is also closing automatically, so that the fire is confined to one room. Teaching a Horse to Pump Its Own Drinks _ HOA, Napoleon!’ the driver shouts, and the horse mounts a platform in front of a water-trough and proceeds to pump itself a drink. As a matter of fact, any other animal of sufficient weight The platform is hinged so as could do the same thing. to descend from an inclined to a horizontal posi- tion beneath the weight of the horse, and the power thus made available is trans- mitted by a rope to the pulley of some shafting overhead. The revolution of this shafting operates the pump. A hose con- nects the pump spout with a noz- zle just above the trough. The trough is mounted upon uprights on when not in use. the platform by means of projections at the ends, a construc- tion that permits it to be automatically tilted and emptied No motor is required. After the first impact of the horse’s feet, the machinery is set in full motion and the operation is en- tirely automatic. By merely walking upon this platform, a horse starts going a chain of machinery that results in pumping water into a trough 81 The momentum of the shafting is increased by the effect of a heavy fly-wheel which gradually attains full speed and then expends its stored-up energy in the operation of the machinery. When the horse has finished drinking and has backed off the platform, the latter is auto- matically raised to its former in- clined position.

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The Dam Confidence Popular Science Monthly of the Californians No flood is feared as the people crowd into this reservoir. It is built in sections so that it may be easily drained for cleaning CENE: The dedication of the Twin Peaks reservoir in San Francisco. One section of the reservoir had been drained, and into this the populace swarmed to listen to the speakers. Flags fluttered and bands played. Only a wall of concrete separated the crowds from the towering waters in the adjoining section. Close beside the protecting dam the people stood, and little they thought of There Is a Right Way to Painta Windmill “TT took nearly as long i. to paint the vane as it did to paint the rest of the windmill,” remarked a painter a short time ago, “for we had to hoist up lum- ber and build a scaf- fold.”” Then he was shown the accompany- ing picture, which tells how the painting can be done without a scaffold. A small ladder, pref- erably with an extension, is secured to the tower, and the upper end firmly lashed to the tail of the windmill. This relieves the weak structure of much of the weight of the painter and makes him feel safe. A man cannot work prop- erly if he is in danger of taking a drop of forty feet at any moment. So, with his mind at rest, he accomplishes his work in short order. When our picture was brought to the attention of a painting contractor engaged in the windmill field, he liked the idea so well that he applied it in his own business. My, hw Anette, ~~ ine (/ Asmall ladder lashed to the framing will save the time and expense of erecting a scaffold when painting the pressure sustained. For the people of San Francisco had confidence in their engineers, and the assemblage was for the purpose of expressing that confidence. In the older forms of construction it was not always possi- ble to clean the reservoir properly without emptying it completely. Dividing it into sections makes the cleansing operation one of very little difficulty. Plowing with a Trolley Car MID the jests.of onlookers, plowing with a trolley car was tried out, not on a farm; but on the streets of San Francisco. The car was of special construction, and was provided with a derrick and six hundred feet of cable for drawing the plow. ; Thus the earth was loosened sufficiently to make its removal an easy matter. The method proved itself far more rapid than that of the ordinary spade and pick methods, and its adoption on a wider scale has been seriously considered. Five men constitute a crew for the usual opera- tions in excavating for new lines or renewing old trackage. In extending trackage, a buffer is placed at the end of the line to prevent running off the track. The ground is then made ready and the cable let out to the necessary distance. Thé plow can be steadied by hand. This plow is drawn by a cable from a trolley car designed for use in street-rail- way construction

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May, 1919 If it hasn't th ie eee Fee are EX) BEST RETAIL TRADE It isn’t BN.D. zs wear ~ Mi Red Woven Label E weave the cool B. V. D. Nainsook in our own Y mills especially equipped to make this fabric. The cotton used is particularly selected for its quality and strength. Thisinsures to you, the wearer, that superiority and economy only obtainable in B.V. D. Underwear B.V.D. Coat Cut Undershirts B.V.D. Closed Crotch Union and Knee Length Drawers. Surtes (Pat. -U. S.-A) $1.00 the Garment. $1.75 the Suit. THE B. V. D. COMPANY New York 'Yos, Str! lhat label Guarantees Vos BY. D. Qualit Vv.

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~ AD the great war lasted one more year or even a few months longer than it did, America would have had completed and in operation a system of modern land-line telegraphs throughout the length and breadth of France not held by the Teutonic forces. This had to be done. The French government telegraphs, of the open-circuit variety, still universally employ the antique tape-recording ma- chines such as we threw into the rub- bish heap in the first days of the Civil War; “bluestone” and. sal ammoniac cells have not yet been supplanted by the dynamo, nor does the typewriter figure in the game of the wires. The slowness, sluggishness, and in- efficiency of the system during hos- A This wiring diagram shows the clean- cut method of actual connections tilities was astounding. The British government railed and fumed and fussed about it. One high official even went so far as to complain publicly, and in the course of his remarks expressed no surprise that the “Big Berthas’” still thundered at the trembling gates of Paris as they had thundered for four crimson years. John Bull kicked, M. Poilu shrugged his shoulders; but the old tape ma- chines continued to take their time in negotiating the most vital messages. The American Telegraph in France It did its part in overthrowing Berlin By Samuel W. Beach, Chief Electrician Radio, U. S. N.R. Entered then the Yankee. He fussed not; neither did he hesitate or postpone. His doughboys in khaki and his gobs in blue laid aside their shooting-irons, their gas-masks, and their military dignity, shouldered picks and shovels, strapped on pole-climbers, grasped comealongs, puckered their lips to the tune of “Dixie,” “Yankee Doodle,” or “‘Madelon,”’ and made the fur fly along the turnpikes and rail highways of France from Brittany to the Hindenburg line, and from the shores of the English Channel to the frontiers of Spain. Telegraph construction work is es- pecially difficult in the western part of France, due to a rather thin soil in places, and solid rock beneath into which post-holes have to be blasted. But these boys, disdaining fatigue, snubbing holidays, scorning those rocks, carried the work ahead so rapidly that soon the main arteries were completed. Big, sturdy Ameri- can Morsemen, skimmed from the cream of the profession in the home- land, oiled up their typewriters and their sending arms, American relays sputtered, American sounders clicked and clattered, and John Bull ceased complaining, while M. Poilu let his lower jaw fall in blank wonderment. One of the main faults of the French telegraphs is the scarcity of apparatus for automatically repeating from one line into another. Apparently they prefer to do this by hand. Their cir- cuits are necessarily shorter than ours, so that long-distance telegrams are re- layed by hand a number of times while en route, and their transmission is delayed accordingly. - To defeat those well-nigh fatal delays, automatic telegraph repeaters were installed in the more important base offices by the A.E.F., the type of apparatus selected for the work being that now used almost exclusively by the American Telephone and Tele- 8k Popular Science Monthly | graph Company, but which are little known as yet by the telegraph frater- nity at large. Diagram A shows the actual connections, and Diagram B shows the theory as simply and plainly as possible. It is the latter drawing that we shall follow in our description. The heavy lines in the diagram indi- cate the routes of the main-line con- nections, while the thin lines trace the secondary circuits. When at rest there are currents flowing through both the east and the west lines; their line coils, Nos. 1 and 6, are magnetized, holding their re- spective relay tongues to a close. Should a distant office on the west line desire to ‘‘send,”’ his first action is to open his key. Instantly line coil B The heavy lines indicate main-line routes, while the thin lines are secondary circuits No. 1, and the local relay coil, No. 4, demagnetize, allowing their respective tongues to fall back. The east line, entering the apparatus through line coil No. 6 and relay tongue E, becomes disconnected at contact No. 7, when that tongue falls back, so that the east line goes open in sympathy with the west. Now, when the east line thus opens, the line coil 6 becomes demagnetized, and were it not for the little secondary coil, No. 18, the relay tongue F would fall back, break- LGA ORNL IENE SEITE ESPN VET? POE

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ly ng mn. li- n- he its he nd re- is oil net :* ive tus lay at alls 1 in nen il 6 not’ the ak- The Standard Spark | Pe Plug of America First Choice In Every Field AC Spark Plugs have won the overwhelming preference of engineering experts and man- ufacturers in every branch of the automotive industry. Aviation: At the outbreak of the war the United States Government invited the spark plug manu- facturers of this country to submit plugs to be used in an aviation motor of 125 pounds compression. The result of these tests was the adoption of AC Plugs for Liberty and Hispano-Suiza airplane motors. At the time of the signing of the armistice we were producing 40,000 airplane plugs daily— more than the combined outputs of either France, England or other American makers. , These airplane plugs were of the same basic AC design used for years by the leading automobile, truck and tractor builders of this country. Ordnance Tanks: Army engineers choose AC Plugs for a large number of the ordnance tanks built in this country for overseas service. Army Trucks: Most of the trucks bought by the United States Government were AC-equipped. All of the standardized Government Class B trucks were equipped with AC’s. Motor Cars: For years AC Spark Plugs have been standard factory equipmenton by far the major- ity of high grade passenger cars built in this country. Trucks, Commercial: Most of the better known trucks are equipped regularly with AC plugs. Tractors: Aglance through the list of manufac- turers below will show that many manufacturers of high grade farm tractors have expressed a decided preference for AC Spark Plugs. To the spark plug buyer this concerted endorse- ment can mean but one thing. Engineering experts in every line, men who have the apparatus and scientific knowledge necessary for discriminating tests, believe absolutely that AC Spark Plugs are the best spark plugs. That preference for AC’s extends from the United States Government down. You can make no mistake in following such example. Champion Ignition Company, FLINT, Michigan These manufacturers use AC Spark Plugs for factory equipment Acme Truc Daniels’ Hatfield Maytag Peerless Singer pele: Davis Haynes McLaughlin (Canada) Phianna Smith Motor Wheel Ahrens Fox Fire Trucks Deere Tractors Herschell-Spillman Menominee Trucks Pierce-Arrow Standard Trucks American-La France Delco-Light Hispano-Suiza Midland Trucks Pilot Stearns-Knight Anderson Diamond T Trucks Hudson Knight Premier Sterling Motors Apperson Dodge Brothers Hupmobile Trucks Reo Sterling Trucks Appleton Tractors Dorris Jackson Riker Trucks Stewart Trucks Brockway Trucks Dort Jordan RobinsonFireTrucks Straubel Engines Buffalo Motors Dusenberg Motors Jumbo Trucks Rock Falls Stutz Bugatti Eagle Tractors Kissel Kar LeMoonTrucks Rowe Trucks Titan Trucks uic Essex Klemm Trucks rucks Rutenber Motors Tower Trucks Cadillac Federal Trucks Kleiber Trucks Samson Tractors United States J. I. Case T. M. Co. F-W-D Trucks Knox Tractors Oakland Sandow Trucks Motor Trucks Chalmers Gabriel Trucks La Crosse Tractors Old Reliable Trucks Sanford Vim Trucks Chandler Genco Light Lalley-Light Idsmobile Saxon Ward La France Chevrolet G. B. S. Motors Liberty Packard Scripps-Booth Trucks Chicago Trucks G. M. G. Trucks Liberty AircraftMotors Paige Scripps Motors Westcott Jole Gramm-BernsteinTrucks Locomobile Pan-American Seagrave Fire Trucks White Continental Motors Halli Trucks Marmon Paterson Seneca Wilcox Trux Crane-Simplex Harvey Trucks Master Trucks Patriot Trucks Signal Trucks Wisconsin Motors U.S. Pat. No. 1,135,727, April 13, 1915, U. S. Pat. No. 1,216,139, Feb. 13, 1917, Other Patents Pending. 85

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SS eas ee tee ae ag ee ee Sa CT ETE Seats Se ee ing circuit at contact No. 2. Should this actually occur, both contacts, No. 7 and No. 2, would be open, rendering it.an impossibility for either the east or the west to restore the lines to a normal. close again. The tongue F must be kept closed - while the west “sends,” so that the latter may at all times enjoy an un- broken pathway through contact No. 2. AB and DC are uprights of spring steel, each pair being connected by an insulating medium (indicated by di- agonal lines in the diagram), so that they move in unison. When the contact No. 7 is opened through the demagnetization of the coilfNo. 1, the springs DC, no longer held to the left by tongue E, open con- tact No. 16. At this instant, and before the tongue F has had time to sever connection No. 2, the current from local battery LB, ascending to contact No. 13, has had two pathways to choose. It may either travel la- boriously through the coil No. 14, through 15 and 17 to coil 18, magnetize that coil in turn, and then meander on- ward through 19, 20, and 5 to the ground; or it may, and does, take the far easier road by disdaining coil No. 14 entirely, parting company at 13, and making for the ground through the one coil No. 18. The latter coil now being magnetized, the tongue F is held to a firm close at contact No. 2, even though there is no _ current flowing through line coil No. 6. When the western operator closes his key to carve out his first signal, the contact No. 2 being unbroken, the entire apparatus falls back as it was in the beginning. The western current magnetizes coil No. 1, jumps through tongue F and contact No. 2, through key No. 3, magnetizes local relay No. 4, picks up more battery, and jumps to the ground from 5. When coil No. 1 is thus magnetized, tongue EF closes contact No.7, again closing theeast line through key No. 8, local relay No. 9, addg the battery, and goes to the ground. Should the east open to send to the west, the action heretofore described jg simply reversed, the action of the secondary circuit being as follows: The local current reaches 13, but is prevented from jumping to the ground through coil No. 18, because contact No. 21 opened when, due to the de- magnetization of coil No. 6, the tongue F fell open. The local current then has no choice other than to continue onward from 13 into coil No. 14. This coil it magnetizes, holding tongue E to aclose. As the tongue E is closed, the spring contact No. 16 is also closed, : affording a pathway for the local cur- rent after it leaves the coil No. 14, through 15, 16, 19, 20, and 5, to the ground. In practice there are switches, re- sistances, condensers, etc., as pictured in Diagram A, the various uses of which are obvious. How to Make a Garden without Soil If you can’t go to the country make the country come to you ITY dwellers who have an in- stinct for gardening are often heard to complain bitterly that they are denied all access to the soil, and are thus prevented from gratifying their horticultural tastes. Such people Some kinds of seed grow very well in a moistened sponge will be surprised to learn that there is such a thing as gardening without soil, as anyone who has a convenient shelf near a sunny window may easily prove. A number of bulbous plants, of which the most familiar are hyacinths, will prosper in glass jars filled with water. Crocuses in great variety, not to mention many another charming flower, may be raised in the same way. Several kinds of bulbs will blossom quite freely without either soil or water. Such is the case with the common colchicum and several of the fine amaryllis lilies, as well as the re- markable “‘monarch of the East,” which throws up a huge and grotesque bloom often as much as two feet in height. All that is necessary is to By Percy Collins place these bulbs in a saucer, or even on a shelf, in a good light, and nature will do the rest. The gardener to whom soil is denied will soon discover that many kinds of seeds will sprout and grow almost anywhere, pro- vided they are kept moist and in a fairly warm atmosphere. One plan is to wrap a piece of felt or flannel around a brick, which is then placed in a dish of water. The water soaks up con- stantly through the substance of the brick, and seeds scattered on the moist fabric will soon put forth shoots and roots, making an interesting novelty. Instead of a brick an ordinary sponge soaked in water = Mi satge 2 W Nuit quay 1 used; or hollow clay ——~. ee... SUIT MM: BAZZAZ a VN f \ shapes, in the form of amusing heads or animals, may be purchased from stores that sell such novelties. Per- \ LNT i ! mnt I | | i) il | A little bit of nature in a city flat brightens the days for those who have to stay in the hot city 86 Popular Science M onthly Tier ceo FIN FROE LIEN

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r= ads om er- weeny May, 1919 Movie of a Man Arriving Home in the Dark» with apologies to Briggs '> A HIT THAT DOOR IF IN] LoCATES FAMILIAR WASNT FOR THE LITTLE] CORNER OF WALL LOCATER EASIIN’ * THE OLD KEYHOLE STANDS OUT [NO TROUBLE WITH THE. LIKE A LIGHTHOUSE WITH THE. |LOWER STEP AND EXPLAIN~ ING TO FRIEND WIFE, HERE IT IS— SHAR : CORNER OF TABLE , craw K ae BuT GET THAT AND ne ed ; VY - NR ALITTLE LIGHT THAT GUIDING STAR GUIDES YOURIGHT! Save Skin, Shins and Dispositions! OUR shins will always tell you where the rocking chair lurks in the dark— you never fail to find it! But wouldn’t it be better and easier to use the Ingersollite Locater—the little luminous tack that you can put almost any place? Because it carries a permanently luminous substance on the head, it glows a pale green light that shows you just where to go and what to avoid. §ngersot tite Near the keyhole —on Because it glows in the the lower step—on the dark, you don’t grope chair—rocker —on the OCa e. omg around for the light— you just walk to it and bathroom door—near the electric push button — turn it on! the Locater will always guide you right! Buy them today—and tonight you’ll appreciate Then there’s the Ingersollite-Pendant — a_ the handiness—the wtility—of these little lumi- little glass tube for the electric light chain. nous guides! Robt. H. Ingersoll & Bro. Makers of Ingersoll Radiolite Watches __-. 315 Fourth Avenue, New York | i New_ York, _ Chicago, h ' San Francisco, Montreal, Buenos Aires, Shanghai, “as! Ghar oa een fall dat-Oy-Ta: London (Ingersoll Watch . Co., Ltd. Distributors.) The Ingersollite Locater, Price 25c. The Ingersollite Luminous Pendant, Price 25c.

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Popular Science Month haps the best seeds to use for ex. periments of this kind are those of mustard and cress, especially ag the young plants may be eaten ag q salad. Carrot ferns and moss trees are both interesting curiosities, easy to cultj- vate. Cut a couple of inches off the top of a big carrot, and scoop out the center of the piece so that a kind of cup is formed. Hang this in a good light by means of a wire, and keep the cup - filled with water. Very soon pretty, fernlike leaves will sprout and turn up- ward, and in a short time the bit of carrot is transformed into a very decorative object. Moss trees are simply cushion- shaped tufts of the moss that is com- mon in fir woods, fixed by means of a long pin to the top of a stick. They can be easily made during a holiday The lowly spud blossoms forth with a family of young tubers if kept in the dark excursion ; and if subsequently the moss is constantly wetted, it will flourish for months—even for years— in any room to which a reasonable amount of fresh air is admitted. at regular intervals. Trees may be raised from acorns, chestnuts, and the like, in bottles of water, and will continue to thrive for years if a little judicious root-pruning is practised from time to time. But in these and all other experiments with plants where standing water is used, one or two small bits of charcoal should be put into the vessel to keep the water sweet and pure. ; Probably few persons know that excellent new potatoes can be raised from old ones by the simple process of shutting up the latter in a dry, dark box. The old tubers should be two years old to get the best results. Furthermore, it is essential that a really dry and really light-tight box be used. After a few weeks the experi- menter will find, when he opens the box, that new potatoes are budding off from the old ones; and the process will continue as long as the old tubers have any living substance left in their shriveled skins. There are several kinds of so-called “resurrection” plants that give good results when grown in a room. Prob- ably the easiest of these to grow is a kind of moss, called selaginella, which is a native of Texas.

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i} Banished Sounds How We Metallic EFORE The Brunswick Phonograph ever came to market, Brunswick execu- tives were insistent upon a vital better- ment: Reproduction. We had been making phonograph cabi- nets for others for years. We had won top place during the past 74 years in the wood- crafting art. To stake our reputation on a Brunswick Phonograph was a momentous undertaking. And so tone reproduction was studied for months. We tried every known method, the ones then accepted as supreme. But every phonograph we ever heard in all our tests had good tones and bad tones, alternating in annoying frequence. Higher Standards Our tasks was to do away with the so-called metallic sounds. These, we found came from me- tallic construction. Tone waves must vibrate to attain their vol- ume. And so, as a superlative feature of the Brunswick Method of Reproduction, we evolved the scientific Brunswick Amplifier under our own patents. It is built entirely of moulded wood. This achievement, all acknowledge, is one of the great steps in the progress of phono- graphic art. It brings out tones hitherto lost. It banishes the raucous. Another amazing advancement is the Ultona, our own all-record player—in-built, not an attachment. This reproducer, at a turn of the hand, presents to each make of record the proper needle and diaphragm. Each record is played at its best. The Brunswick Method of Reproduction is one of the greatest triumphs of The House of Brunswick since its establishment in 1845. Hear—Then Judge You owe it to yourself and to your family, as you decide upon which phonograph, to become acquainted with The Brunswick. In your town there isa Brunswick Dealer who will be glad to play this super-phonograph for you. THE BRUNSWICK-BALKE- COLLENDER COMPANY 6Fricuss CHICAGO and NEW YORK Branch Houses in Principal Cities of United States, Mexico and Canada Canadian Distributors: Musical Merchandise Sales Co., xcelsior Life Building, Toronto Brunswick SORE OE TN KE CRE SK RA

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FL. — > > } 2 M 4 Mail coupon to nearest house for Booklet No. 84 AT, telling all about this new cleaner. WESTERN ELECTRIC COMPANY “Built From a Woman's Viewpoint Why is it that women who know prefer the Western Electric Vacuum Cleaner? It is be- cause this machine is constructed on principles which a woman instantly recognizes as correct. She knows, for instance, that brushing is needed for many kinds of cleaning; that threads, hair and lint imbedded in a rug cannot be taken up by suction alone, but must first be loosened by abrush. She knows, too, that a carpet tracked with mud cannot be satisfactorily cleaned un- less it is brushed before the suction is applied. She knows that there are many times, too, when a brush should not be used, and that a brush might be operated in a vacuum cleaner at a speed so fast that it is damaging to the rug. All of these conditions have been pro- vided for in the Western ElJecfric Vacuum Cleaner A brush was built into it—and you can operate - the brush or not as you need it simply by turn- ing it on or off. When the brush runs, it is not at the high speed of the motor, for the speed is slowed down by a worm gear. By this means we have combined a motor, creating a powerful suction, with a brush so regulated that it will be efficient yet gentle. These features account for the immediate pop- ularity of the Western Electric Vacuum Cleaner—the demand for it, since its in- troduction last fall, has made neces- sary an increase of more than 500 per cent. in our manufacturing estimates. Gentlemen: INCORPORATED describing the new P Western Electric No. New York Chicago . 12 Vacuum Cleaner. Kansas City San Francisco ward. It is as if eight spokes of WESTERN ELECTRIC CO., Inc. Yd Please send me Booklet No. 84AT, Other Distributing Houses in — Cities ok NAME > = ee ee ees ee ee ee ee xx a! ADDRESS 90 Popular Science Moni Turning a Tree-Stump an Outdoor Table ‘HE stump of a tree that has } cut down will serve as support an outdoor table. Four-by-four jy scantlings of suitable length are as flush with the top of the styms crossing each other at right. angles From each of the four angles of thes four-by-fours, two-by-twos extend out A permanent picnic camp may be. made from discarded tree trunks~ wheel extended outward from the center of the stump. Boards nailed on the top complete this eight-sided table. Eighteen-inch sections sawed from the trunk of the tree serve as seats.—C. L. MELLER, You Can Learn How to Read a Micrometer EMEMBER that the micrometer divides the inch into one thoussaaay parts. The edge of the outer thimble ‘is marked in twenty-five divisions. Ro- ‘ tating the thimble through one division@ advances the spindle .001 in. i The number of rotations of the © thimble from zero is counted on the .200 nM 7) Revolution line +O § 2 Thimble € lor el 224 Micrometer-reading comes easy after a careful study of these instructions — inner sleeve by divisions. Every © fourth of these divisions—four revolu- 7 tions of the outer thimble—measures .100 in. Forty revolutions measure © § the full inch. Every full revolution of 7 § this thimble advances the spindle .025. 7 A little study of the illustrations will 7 make the operation of micrometer- reading quite clear. Speed in reading comes only with practice—and a very little practice should enable the op- erator to read his micrometer almost at a glance.

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; f i : } } * at niet. one PATTON San Francisco, Cal. “They Give the Clearest and Most Penetrating Light I Have Ever Driven Behind”’— That is what Dr. B. H. Carter of Meriden, Conn., says about the Dillon Multi-Vision Lens. It is the universal verdict. Everywhere, in all parts of the country, wherever automobile headlights are dis- cussed, the Dillon Lens is spoken of in terms of appreciation. No other lens ever met with such sponta- neous and unqualified approval from so many motorists. You never hear an owner speak indifferently about his Dillon Lens. You never hear him damn it by half praise. This nation-wide acceptance of the Dillon Lens can be interpreted in only one way. Such a remarkable condition could not be “‘created’’ or brought about save through and by the superior performance of the lens itself. If you have never driven behind the Dillon ns, do so at your earliest opportunity. The experience will give you a new idea of headlight efficiency and will serve to add your voice to the chorus of Dillon praise that is ascending in ever increasing volume from one end of the country to the other. The Dillon Lens gives a big, glareless light, almost double the usual area of illumination. A light that leaps straight out at both sides, down in front and far ahead. The whole roadway is illuminated so that you can see clearly just where you are going and what dangers, if any, confront you. This big, safe light gives you confidence as you sit at the wheel and minimizes to a marked degree the glare from the headlights of passing cars. The Dillon Lens is legal in all states and fully guaranteed. Equip your car today. Then take ten safe, pleasant night rides and if not fully satisfied return the lens and your money will be refunded. For sale by dealers and garages. If your dealer cannot supply you write direct, same price, $3.50 per pair, post paid, any size, anywhere ji in the U. S. A. Manufactured by DILLON LENS & MFG. CO., Wheeling, W. Va. He EER DEALERS CAN BE SUPPLIED PROMPTLY BY PITTSBURGH PLATE GLASS COMPANY PITTSBURGH, New York, N. Y. Chicago, Ill. Philadelphia, Pa. Baltimore, Md. Dotret. Mich. Boston, Mass. Rochester, N. Y. Kansas City, Mo. Omaha, Nebr. High Point, N. & St. Louis, Mo. Columbus, Ohio Birmingham, Ala. Houston, Tex. Davenport, Towa. Cincinnati, Ohio Cleveland, Ohio Dallas, Tex. Minneapolis, Minn. St. Paul, Minn. Buffalo, N. Y. Brooklyn, N. Y. San Antonio, Tex. Grand Rapids, Mich. New Orleans, La. Oklahoma ie A Okla. Atlanta, Ga. Great Falls, Milwaukee, Wis. Savannah, Ga. Memphis, Tenn. Des Moines, Iowa. Jacksonville, re Newark, N. J. PACIFIC COAST STATES Seattle, Wash. Timms, Cress & Co., Agents, Portland, Ore. 91 PAINT COMPANY Los Angeles, Cal. WESTERN CANADA INDEPENDENT ELECTRIC CO., Regina, Sask. EXPORT MANAGERS J. J. NORDMAN & CO., Pittsburgh, Pa.

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The Daylo is anecessary part of every Auto Truck Equipment senasansateseeceseseerenneverrameasaats pessoa ese seceesseseenanecessestas steers “As necessary as a monkey wrench or oil can” Ed says when he forgot his Daylo last night, there was a In half an hour his engine balked, his lights went ‘on the blink’ and he ran out of matches—and cuss words. hoodoo on his trail. Jim keeps two pet Daylos in his kit—one in the tool box, and one back of the seat cushion where he can reach it instantly. Bill carries a “2659 Daylo” in his mackinaw pocket and he has a set time to buy his fresh Eveready Tungsten battery. 608 The Light that says: — —‘There it is!” | (Say those who drive at night) All Eveready dealers are now well stocked theme in shortest possible time, agonse rt NIGRAPH AUTO- MATIC TRANSMITTER, cain rator would. "Rdopted b by wt. 6 styles. Catalog fre aime tie Brees TRY "EM AT OUR EXPENSE Moke Ueda Write > to-day a4 details of most liberal, con The Brictson 1015 W, O. W. Bldg Today—Now! Dept. of Signaling, ee ee new Free Book on fee —— men pr this ipportentw i tells Tae ‘ ee Room 9205,1810 Wilson Av., and basement. AXIM Site It eliminates recoil and all noise of FREE the report, and steadies your aim. BQOK Fits any .22 or .22 high hat xy x == x lig Satesiocs Target Practice ( hy Fit your 22 with a Maxim Silencer and get no end of fun -_ season practicing in backyard LENCER MAKES YOU ABETTER MARKSMAN wer rifle. Book of stories of actual users, free. &S MAXIM SILENCER CO. 91 Homestead Avenue., Hartford, Conn. 92 Popular Science Mo A Depth-Gage and How to Make It HE design of the depth T lustrated is very simplar — the wire at one end and the grad scale at the other, it can be used fare number of purposes, such as counter. bearing, accurately measuring the P= KNURL - shy REQD &. 0) LAr 2-R For measuring recesses, counterbearings, etc., a device of this sort is indispensable depth of a recess, and other things of a like nature. The base is made of a piece of 5/82. in. tool steel, allowing material enough to finish a'l over. If tool steel is not available, cold, rolled, or ordinary ma- chine steel will do. The width of slot Z should allow the 4-in. scale to slide freely with no play on either side. A groove with a 32-in. radius keeps the wire at right angles to the base when adjustments take place. Much care should be taken to have the scale slot and wire groove as nearly square at the base as possible, so that the gage may be used as a square if desired. ? # The completed depth-gage ought to look like this illustration The wire is made of 1/16-in. diame- ter drill-rod, with a 14-in. ball forced upon one end. The measuring end should be hardened and drawn to 4 light straw color. The two knurled nut and clamp screws are made of soft steel. A slight improvement can be made by counterbearing the small end of the nut enough to allow inserting a small coil spring, which will always keep 4 slight tension on the measuring rods when the clamps are loosened for ad- justment, making it much easier to set to a given size.—A. DANE. LR NET ROPES LMI ETO RRR SEE EO

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| pe bs + aoe £8 8 of a 5/82. Lough is not y ma- f slot . slide e. keeps . base Much > scale lare at > gage 9 m | | | | | | 1 | 1 | i ' J it = uh. (Wy HUM a 4 Se i wi n= Why Automobile Engines Are Ten Years Behind the Times name of a definite liquid, like water, alcohol, or sulphuric acid, but the name of a variable automobile fuel. The gasoline of today is not the gasoline of ten years ago, not the gasoline of last year even. Each year what you call gasoline is becoming heavier—more like kerosene. But automobile engines are designed to burn the gasoline of ten years ago—not the fuel now called gasoline. Six million cars must be kept in motion. But there is not enough gasoline of the kind that they are intended to consume to go around. So, the oil refiner has to blend a little gasoline with kerosene-like fuels to supply the demand. These new low-grade fuels don’t vapor- ize as easily as the old gasoline— particularly on cool mornings. It’s hard to start. But worse than that is this: The heavier portion of the fuel- blend is not converted into “vapor.” It collects in drops. Puddles of it form in the mani- fold. It works down into the crank- case, “cuts” the lubricating oil, and ruins the engine. : er ae isit? Not the , 0000000 © © The kind of gasoline that most cars ought to burn can be bought only in a drug-store at drug-store prices. Most cars are ten years behind the times. They ought to be burning gaso- line of ten years ago; they try to burn the fuel-blend of today and don’t—quite. There is only one way to meet the situation:—Make the engine so that it will burn these new heavy fuels. Make it so that only “vapor’’, not raw fuel, is fed to the engine. That is exactly what the Chalmers Com- pany has done. In the new Chalmers car is an engine scientifically designed to use all the “gasoline” —not just a part of it. The Chalmers engineers gave the mani- fold the Hot Spot that immediately vapor- izes a drop that touches it and they de- signed the Ram’s-horn manifold, so that all the six cylinders would receive an equal amount of mixture. The result is:— 1—You get more power. 2—You start quickly. 3—No raw gasoline trickles into the crankcase to cut the lubricating oil, which means that ; 4--You save money in repairs. This is the first of a series of six bulletins in which the won- derful features of —— : the new Chalmers ——TX will be explained o00000 (Q) : ° mn Illustrations No. 1 and No. 2 show in an enlarged way the difference in globules before (2) and after (1) being “‘cracked up’’ by the Chalmers Hot Spot. ye D aaa ala 8a I J vie Walaa awaai'® ui y ry 1 ab ebavalarstatalatala lal aialatt a rr ory oe ) WZ Mon a ee eae is Neer BU nO \ ONG Fe PARLE, iy Bull SZ oe SF MRD tne ALO = wl Fil

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“Wed Never Have Got Here Without It” “Just think of all the fishin’ we missed before we Zot our Harley-Davidson.” There are scores of places—secluded lakes, half hidden streams, far distant hills and woods—that can be reached only with a motorcycle. And there is where the fish- ing, is best, where Bame is most plentiful —and you can depend on gettin}, there and back with a Harley-Davidson Miles are but pleasant minutes with this motorcycle, And it does stand the “aff” —hard riding over give-and-take roads holds no worries for it. See the new models at your dealer's store. The Motorcycle that is Being Talked About Harley-Davidson Motor Co. Milwaukee. Wis. es’ J r at — a: — cote a You Can RENT This Phonograph on our new plan! $10 puts this Young’s ‘| Superior ph in your home on 30 Days’ Trial! Plays all makes of disc records. Cabinet size, 47 ins. high. Rental ™ gain ever offered. Limited. Today. YOUNG'S SUPERIOR PHONOGRAPH 62 W. Madison St. Dept.P 7 Chicago, sil.

acceptance. love or any subject. Words Today. atete ot Dhongeraph bar: CHESTER MUSIC COMPANY 538 So. Dearborn St., Suite, 310 CHICAGO, ILL.

WRITE THE \VWORDS FOR A SONG We write music and guarantee publisher’s Submit poems on patriotism, Don’t delay. Send

Popular Science Mom To Prevent the Loss of | Motorcycle Push-Rods N many makes of motorcycles, ; QO the intake tappets are not Ba : carefully adjusted, the push-r fly off and be lost. I had rr perience recently, and on investigation found that the intake valve-spring wag ' too strong to permit the valve fune. tioning automatically. I had to come home on one cylinder. To avoid a repetition of ‘< this, I secured Cen cus, a couple of ~< HERE lengths of old CARBURETOR watch-chain %| from a jeweler’s junk-box, and attached them to the push- rods as shown in the illustra- tion. One end of each chain is soldered near the middle of each push-rod. The opposite ends are at- tached to a piece of tin cut as shown, and secured under the nut holding the carburetor bowl. The intake push-rods work as usual, but should the push-rods jump off they stay with the machine and can easily be inserted again.—JOHN E. Hoce. A Paper-Winding Machine for Barber-Shops

No need for that exas- perating loss of push- rods if chains are at- tached to the push-rods NEW paper-winding machine, in- vented by A. Ross of Buffalo, N. Y., winds three different-sized rolls of paper from a supply roll to be used for the head-rest of a barber’s chair. As a rule, the barber buys his paper already wound, which is extremely

eae BN

NOT TOYS BUT REAL APPARATUS The same as used by operating companies. You had better send your order immediately to insure prompt delivery, as this equipment will not last long at these prices. 110-Volt Hand Genera’ uction Coils, each, postpai a Con ps Ess Pleas

tors, Shere each, postpaid $3-90 each, postpai ars 4. PE ABR 8 ** 65 or 6 bars each, postpaid 5.00 Telephone Transmitters, each, pos’ G ringers complete with bells, each, postpaid “ Telephone Receivers, each, postpaid . with arms, tpaid .85 -60 2M. F.’ each 60 . F. each, pos' a id - 60 ° . ° ° » 1.60 paid » » - 2.10 1 tye Telephones . 4.50 perdozen . ° ° -25 end money order, check or cash with order ELECTRICAL SPECIALTY COMPANY Dept. S, 48-50 So. Front St., Columbus, Ohio Dept. S, 128 So. 11th St., Philadelphia, Pa.

With this device the barber winds his own paper for head-rests at half the expense of the usual roll high priced. With this device the barber is able to cut the price more than half. A roll of 13%-in. paper costs five cents. Wound from a supply roll, it costs only 114 cents per roll of 14 in. The device winds a roli of paper im fifteen seconds. The shaft catching the paper winds it, tells you the size, cuts it, and the roll is ready for

use.—A. Ross.

— el raayrernen e

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rine ne, in- uffalo, d rolls e used hair. 3 paper remely sts five - roll, it f 11% in. paper in catching you the eady for Both make Electricity:— the Power Station Dynamo and the Fiery little Columbias HE big dynamo whirling in the power station makes electricity for the big jobs—to light the city; to run the factory full of ma- chines; to propel the street cars. The fiery little Columbias standing quietly behind the scenes make elec- tricity for all the little jobs—to ring bells and buzz buzzers; to make tele- phones talk; to run toys for the little folks; to ignite farm engines, autos, trucks, tractors, and motor-boats. THE DRY BATTERY HE world is so used to having the Columbia Dry Battery always at its beck and call, the little red fellow’s work is accepted as a matter of course. Yet he is really one of the great marvels of the age—marvelous for what he does— _ Storage mabe y patteries Columbia marvelous for his power—marvelous for his long life. Columbia Dry Batteries are appropriately called ““The handy-men of the world.” THE STORAGE BATTERY Deas Columbia Storage Battery is backed up with a definite guarantee that makes certain for the purchaser the actual per- formance to which his purchase entitles him. And everywhere there is Columbia Service organized to back up that guarantee. Your Columbia Storage Battery has the protection of the Columbia Pyramid Seal stamped on its lead terminals. No one but authorized Columbia Service Station experts will break that seal—they, and they only, have the authority and equipment for resealing. And if your battery should fail to live up to its guarantee, its intact Columbia Pyramid Seal will show at once that the battery has not been tampered with and you are entitled to thorough repairs or another battery without additional cost. Columbia Storage Battery Service is all around you—it will be well worth your while to drop in and let them show you how they will save you annoyance and expense. d &

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= Hey Jimmie leme try your wheel The whole crowd will want to try this dandy Indian the very first time they see it. It’s built husky like the Indian Motocycle, it’s speedy, too, and a dandy hill climber. : The Indian Motocycle type forks, saddle and handlebars make it comfortable and easy to control. The tank contains two dry batteries for the electric head light. | Send us your name and address and we will mail you a beautifully illustrated catalog, and the name and address of the nearest Indian dealer. HENDEE MANUFACTURING CO. SPRINGFIELD, MASS. | Sndian Motobike i Popular Science Mon Making Cabinet Clamps fr¢ Broken Hand-Screws el and about woodworking shops there may always be picked up any — number of broken hand-screws, A good way to make use of these broken hand-screws is to turn them .. into clamps. Cut a hand-screw in tyo at H, and then cut off the beveled end, How broken hand-screws can be used to advantage as clamps for gluing parts thus making two stationary jaws for the two clamps A. ace Cut out the center as shown in A to fit snugly at B, and glue these to- gether, or fasten them with screws from the side. Make the wooden strips the same thickness as the jaws, or only slightly cut out the notches on the bottom to hold the movable jaw. The sliding jaw is made from the other half of the hand-screw cut into two pieces (E E). A 14-in. iron rod is bent to the shape D, and two metal clamps shaped as C. Fasten these to the sides of E. When gluing together panels and frames these clamps can be used to hold the pieces together until they are dry. These clamps will prove invaluable about the shop, for they may be used equally well on a number of operations.—E. J. BOoMIs. To Manufacture a Conduit- Bending Device DEVICE for use in bending the ° smaller conduit sizes for electric wiring is made by screwing a flanged ~ tee to the end of a piece of pipe. A practical pipe-bending apparatus which is recommended for its cheapness and simplicity When using, slip the tee over the conduit to the point where the bend is to be made. Then place the conduit in a vise, or stand on the conduit, and pull or push the pipe-handle. Any curve desired can be bent in this ~ manner, and different-sized tees may be employed for different sizes of conduit.

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4,791,172 REASON For (O}T] ye fexoy ae) fold Every War-trained Man a living Example of the Benefits of Physical Excercise There were over 4,791,172 men in the military service . of our government on the day the armistice was signed. The high degree of physical fitness attained by the men who are returning from overseas and army training camps is the greatest object lesson on the value of physical train- ing this nation has ever had. Outdoor sports will help them hold the gains of army training. If you—a civilian —have been lax in regard to physical exercise, reform your personal habits and go into training to make your- self as physically fit and efficient as a soldier. You owe it to the nation as well as to yourself, tu pe at your best—physically, mentally—so that you may do your part in meeting the new demands of reconstruction. Take up some form of athletic activity. It will strengthen your physical fibre, steady your nerves, add to your reserve of vitality, and increase your personal efficiency. WILSON Sporting Goods The government bought millions of dollars worth of sporting goods for the boys in service—much of it was *‘Wilson.’’ Wilson’s Sporting Goods and Athletic Equip- ment have been a big factor in the physical training of ' our soldiers and sailors. Their superiority is recognized by leaders in every sport. The Wilson line includes equipment and apparel for baseball, golf, tennis, football, basketball, soccer, fishing, swimming, gymnasium and track. Sold by Leading Dealers Everywhere Look up the Wilson dealer in your vicinity, he is well worth knowing and we willbe glad to furnish you his name. Send Coupon for Big Free Catalog Our new Sporting Goods catalog for spring and summer or our fishing tackle catalog will be mailed upon request. mn Wa, Wa | THOS. WILSON &CO,] 2 WwW W ‘ ;

; a a 4 i «de enn we, < PE. ri ae Bogie * e038 a 3 WILSON EQUIPMENT FOR EVERY SPORT 97

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o mind when you select cle: Afterathorough . _ Government engineers _ ican-madeé bicycles, the ~ Military Model was When the Little Ford Knocks It’s time for you to find out why Popular Science Me and to remedy it without delay By G. F. HE thumping and vibration of the big end bearing is familiar even to the motorist of a few months’ experience. To those motorists who have never attempted to take up the big end bearing of a connecting-rod it may seem a more complicated job than it really is, but to the more ex- perienced motorist there is only the danger that certain important details of the operation may be neglected, with serious re- sults. The repair nec- essary depends en- tirely upon how far the wear has been allowed to go, but the most common cases re- quire only a few simple operations, with a minimum of labor and tear- ing down of the engine. The front part of the car should be jacked up as high as pos- sible, raising the wheels at least a foot from the ground so that the repairer may get beneath his car, on his back, without much trouble. The crank-case, which is generally attached to the base of the engine with sixteen bolts, is first removed. Re- member that there is oil in the crank- case, so drain it off before beginning the work. On the bigger cars the removal of the crank-case is a two-man job, and if it is not removed easily a screw-driver or file should be inserted into the joint. In doing this be very careful that the gasket is not destroyed, for if this hap- pens a new gasket will be necessary or oil leakage will result. ROD SLIGHTLY OFFSET Locating the Trouble As the base drops away the crank- shaft and the big end bearings are ex- posed, and here the faulty bearing must be located. The crank-shaft is turned so that the cranks are vertical, when any slackness will make itself apparent by holding the connecting-rod firmly and locating the vertical movement that denotes wear in that particular ‘bearing. The bearing—if it is of the usual white metal-lined type—is held to- gether with two or four bolts with castle nuts and split pins. When these are taken out the bearing cap may be removed together with its liner and the shims (brass packing 98 NOTE CONNECTING Collins pieces) between the halves of the bearing. To do the work right the piston and connecting-rod should be taken out, and while this seems g hard job it is simple to push up the connecting-rod until it is clear of the crank-shaft and then turn the crank-shaft a little to one side so that the rod may easily be drawn out, Never do this when the crank-pin ig at top dead center, for if the piston- ring should be moved up the cylinder beyond the end of the bore, it will snap out and catch on the edge of the valve pecket, often _ rendering the piston impos- sible to move until the ring is broken. The crank-pin is sometimes found to have worn oval, and in this case upon the piston replacement it must be tightened up as much ag possible. Be sure to mark the end of the bearing halves, so that they may be refitted in their relative positions. Note whether the connecting-rod is slightly offset, for if the rod should be assembled the wrong way there will be a great strain upon the rod and on one wall of the cylinder when the bearing bolts are tightened up, that is, if the top half of the bearing will fit on the shaft at all. The edges of the babbitt shell may be made smooth by rubbing them with a sheet of emery-cloth laid on a flat bench, applying an even pressure to the work. If there is much metal to be taken off a file will be necessary. Unless the looseness of the whole bearing is apparent, it will not be necessary to interfere with the top half of the bearing; and should this be the case a new bearing is the only solution of the problem. To Find the ‘‘High Spots” Do not draw the vise too tightly when scraping the bearings Scraping in the bearing consists of using a bearing scraper to remove the portions of babbitt that stand out from the bearing and prevent the whole sur- face from coming in contact with the crank-shaft. To find these so-called “high spots” the crank-shaft should be smeared with Prussian blue, after assuring oneself that there is no grit mee

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ket, npos- nove ng is pin is found oval, case iston nt it tened h as f the ay be tions. od is ld be rill be n one aring if the n the may ° . with a flat to the to be ssary. whole it be D half ye the lution sts of 2B -| — was when > Hygiene was ‘but little known, and practiced ‘less. Today it is the handmaid of | ' daily affairs. | Bauer & Black has devoted twenty- . five years to mak- ing first aid in medicnl science a household word— _ bringing its bene- i Ee reach of all. ec: - ficence within the ' HY GE ie (eT @) 8) 0) Sho} uae ©) Sie 5 0-708 On | PROTECTING HUMANITY ‘al THE products 4 2 pol Ghee by the letters B& B have become mod- els in medical practice. They manifest what sci- ence and skill can accomplish, in- _ genuity invent or _ vigilance create, to safeguard and _ conserve health. ' Bauer & Black has ' taken Hygiene out _of the hospital | sanctuary into the | everyday world. BAUER & BLACK Wakers of Sterile Surgical Oressi ngs and Allied Products - Chicago, New York ‘Toronto

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years. through the bit. Spend this evening with a Wellington Pipe. dealer can supply the size, shape and grade you want at 75 cents and up. Just be certain it’s a Wellington—then relax. Wem. DEMUTH & CO... NEW YORK WORLD'S LARGEST PIPE MANUFACTURERS Relax Just settle down in your pet chair, fill your pipe right up to the brim, light up and let the good smoke roll peace- fully out—that’s relaxa- tion. There's nothing better after a hard day than a quiet evening with your f Mane MARE sy UNIVERSAL PIPE The W. D.C. triangle trade-mark has been the sign of supreme pipe value for more than 50 t is not only on every Wellington, but also on other pipes that we make of every style, sizeand grade. Price for price, grade for grade, there is no better pipe made than a W. D.C. The rich brown bowl between your thumb and fingers is genuine French Briar, broken in sweet and mellow because it was seasoned by our own special process. It’s guaranteed against cracking or burning through. There’s never an unpleasant interruption. and holds all tobacco crumbs that are inclined to roam up The smoke comes, clean and dry, through the fop opening, away from your tongue. The well catches all moisture Any good Zod Learn Piano! shows how you can become a skilled player of piano or organ in your own home, at one ter usualcost. Dr. Quinn’s famous i - Written Method is endorsed by leading and heads of State Conservatories. Successful 26 years. chords at once and complete piece in every key, within 4 les- sons. Scientific yet easy to understand. Fully illustrated. For begin- ners or teachers, old or young. All music free. Diploma granted. Write today for 64-page free book, ‘‘How to Study Music’’. M. L. QUINN. CONSERVATORY, Studio 142 E, Social Union Bidg., Boston, Mass. p THE B “Phe Biggest, Brightest, Best Magazine for Boys in all the World.”’ OUR boy wants ‘‘boy’”’ reading; the kind of stories that thrill and absorb; articles that give him practical information and real pointers on boy activities. Because The American Boy has appreciated the boy viewpoint for years, it is the eagerly sought fa- vorite of more than 500,000 splen- did, normal American boys each month. The American Boy supple- ments home and school in starting HIM right. Give your boy this wholesome reading. 20c a copy on news-stands— $2.00 a year by mail. The Sprague Pub. Co. 28 American Bldg. Detroit, Mich. rr $90to*250aMonth | KreeBool Tells How he SIGNAL ENGINEERING 4 Railroads need men for this important work. Big positions open throughout United States. Big : ee Book tells all about it—tells how you can get the exact training you need. rite for it— Today—Now! Dept. of Signaling, Room 9205,1810 Wilson Av., Chicago | SIGNAL "ENGINEERING Rider A; Every where to ride and ex/@aas hibit the new Ranger “Motor. ; bike" completely equipped with Raag electric light and horn, carrier, | Aes stand, too) tank, coaster-brake, FAIRE “Ranger’’ line of bicycles, DELIVERED FREE on approval : cat « and 30 DAYS TRIAL. Send for 7H big free catalog and particulars’ f of our Factory - direct - to- Rider } marvelous offers and terms. ‘ Lampe, Horns, Wheels, J Wize, all bicyel Bo (~ pane | ag ~ icycles—at half usual! ices. SEND NO MONEY but tell us cxactl what ed. Do not. buy = y 4 Pat 700 need OTT nt wiles Tedey M EAD CYCLE COMPANY Dept mic9 CHICAGO 100 Popular Science M y present. After the bearing lin been wiped clean they must be t one at a time, and applied to the shaft, le, being pressed on as firmly as Ossib at the same time revoluil around the shaft. If there is vere metal to be taken off, the bearing should be properly assembled and b although the piston need hers > serted in the cylinder. Now, i th liner is removed, the high spots will show as streaks in those places that have come in contact with the shaft These places must be removed. The bearing half to be treated is clamped in the vise by an end flange this being the most convenient Position for operating the scraper, though many prefer it as shown by the dotted outline in the sketch. In any event it should be held by a flange only, with the back resting on the vise, ag jam- ming it between the jaws of the vige ig liable to make it buckle. Best Kind of Scraper Scrapers are not expensive to buy, and there are many kinds on the market. The best form is the half. round type, about nine inches long, with two cutting edges. The scraper should be held firmly by the handle and pressed lightly on the work with the other hand. Be sure to make all the cuts in one direction, and only a small amount of babbitt must be re moved at each stroke to secure a clean surface. Try the bearing on the shaft quite often with a coat of Prussian blue, so that the process can be definitely noted. When the patches made by the Prussian blue cover practically the whole surface of the bearing, the bear- ing should be assembled and bolted up for the last few trials. Finally, when the bearing halves ar considered a good fit, they may be re assembled, after making sure that th oil grooves are clear of grit and deep enough. Note that it is very often un necessary to remove any babbitt from the bearing surfaces; all that is re quired to be taken off is a slight amount of babbitt from the bearing cap edges and the lower half of the bearing, the reason being that the bearing is only slightly loose. In those cases where shims are fitted, these will be found threaded on the bolts between the two halves of the bearing, forming a substance to keep the bearing halves apart. The removal of one or more of these shims enables the bearing to be tightened without any filing or scrap- ing, so that when bolted up the liners will be tight on the shaft but not too tight to turn easily. Much care must be taken, in finally reassembling, to see that the bearing 18 lubricated, that the bolts are properly tightened by turning each a little ata time, and that the split pins are I serted, for if the bearings are not taken up equally all around your little old Ford will soon be knocking agail.

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to buy, on the he half. es long, scraper - handle rk with nake all 1 only a t be re- > a clean somzrersme mee A Par ft quite blue, so lefinitely le by the ally the he bear- 1 bolted alves at iy be re that th. ind deep ten un- oitt from at is re- a_ slight aring cap » bearing, earing is se cases e will be between , forming ng halves r more of ing to be or scrap- the liners t not too in finally bearing is . properly little at a 1s are in not taken little old ng agaill. We Back This Trade-Mark With Our Reputation 1 One-piece drop-forged cranks. Hobbed sprockets. 2 bpecial design rear fork, giving extra clearance be- tween wheel and fork sides. Flush rear fork ends, 3 Drop-forged seat-post cluster, giving extra strong grip on seat-post. 4 High-grade padded leather saddle with double action springs. Leather tool bag and complete tool equip- ment. 5 Seventeen process enamel finish of Dayton Car. mine. Tough and long wearing. Heavy coat of copper under all nickel plating, HEN the day’s work is finished, then come the few hours of fun, recreation and relaxation! They are short enough at the best. Why waste evena minute in walking home—waiting for crowded street cars—or riding in them through the delays and confusion of the after-work jam? Swing into the saddle of your Dayton Bicycle! It will take you home comfortably, quickly—and speedily! The air and the exercise will freshen you up and put you in fine condition for a real meal and a good time! Among their many superiorities DAY- Home from Work nachiffy! TON Bicycles are neted for their easy run- ning qualities. Dayton hubs, cups and cones are turned from bars of solid steel. First they are car- bonized and then case-hardened. After the cones are case-hardened the bearing sur- faces are ground absolutely smooth on a carborundum wheel, reducing friction to a minimum. The hub bearings are extra large High- Duty A balls. And, front and rear, the Dayton offers 2-Point hub bearings. No wonder the Dayton runs like a top! See the Dayton line at your dealer’s. Study the mechanical superiorities shown below. Our catalog describes and pictures the Day- ton line completely. Write today for Catalog B-9. I Fis free Cycle Dept.. THE DAVIS SEWING MACHINE COMPANY, Dayton, Ohio 6 Dust-proof head adjustingcone. Extralarge High b Duty ball bearings. Cones case-hardened in cy- anide. 7 Outside joint-head construction. Eleveninner re- inforcements in frame, all dip-brazed. Ss Double anchored fork sides with solid steel spool between plates. Front hub and cups of special design turned from solid steel bar. Two-point frictionless bearings. 10 Seamless crank hanger bracket, extra reinforced.

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r= Took in $10,000.00 “Have had our machine over 3 years and have taken in more than $10,000 on pop corn and peanuts.”’ Bloomington, Ill., Pop. 26,850. Bought Him a Car “Profits derived from Butter- Kist machine first 12 months paid for machine and bought me a $1,200 automobile besides.’ Elec- tra, Tex., Pop. 640. Paid for Itself “Paid for machine out of profits in less than year.’’ Mt. Pleasant, Ta., Pop. 3,874. Increased Other Sales 97% Made 49,015 sales of Butter-Kist Pop corn and peanuts first year and it increased my sale of maga- snes OT. * Evansville, Ind., Pop. known ? Butter-Kist tunity ? Used and praised by Confection- ers, Druggists, Theatres, Variety Stores, Grocers.. Bakeries, Res- taurants, Stationers, Department Stores, Cigar Stores, Billiard Par- lors, Florists, Commissaries, etc., in cities and towns of all sizes from 400 population up to the largest. Our easy payment plan gives every buyer a chance to pay right out of his Butter-Kist sales as thousands have done. So don’t let anything prevent you from investigating. Valuahle |= This coupon has started many a business man on the road to new profits. Each read an advertisement like this and had the a4 horse-sense to know that it doesn't cost anything jut a postage stamp to investigate. If this machine pays big profits in towns of 300 and 400 population as well as in the largest cities, then no man in business can afford to ignore it. Mail the cou- pon now for full facts and amazing-success records. Holcomb & Hoke Mfg. Co. 140 Van Buren St., Indianapolis, Ind. 3120 Ye The Greatest Payer That a Store or Theatre Can Have Do you realize that America is now on the threshold of the greatest business activity this country has ever Every day we are getting letters from Drug- gists, Confectioners, Grocers, Bakers, Department and Variety Stores and Film Exhibitors who want the the enormous trade let loose by the ending of the war. What are you doing to seize this life-time oppor- Will you start right here and now by sending for our wonderful Butter-Kist book and see the sales records and photographic proof of the hundreds and thousands of stores and theaters that are earning from $60 to $250 clear profit per month AND MORE from a little waste floor space 26 by 32 inches ? Pays 4 Ways—Look! 1—Motion makes people stop and look. fragrance makes them buy. trade for blocks. theater attendance. Pop Corn Ma arly . SOx — oy 4 BORE OR ¥ = BG ‘Reg 4 4 : 4 a bac Pop Corn Machine to attract and expand 2—Coaxing 3—Toasty flavor brings 4—Stimulates all store sales or Don’t think you have to be located in a busy center to make this ma- chine pay. The beauty of the Butter- Kist is the way it draws trade to you. | For Proofs, Photos and Prices HOLCOMB & HOKE MFG. CO. 140 Van Buren St., Indianapolis, Ind. Without obligation, send me your free Butter-Kist book—‘‘America’s New Industry’’ with photos, sales aaoeees. and estimate of how much J can make with your machine. Popular Science Month Here’s a Match-Safe for the Sportsman ; ee are many kinds and styles of match-safes for the outdoor man, but the simplest yet seen is One made of a section of bamboo. A section is cut out, one end below a ring in the cane, the other cut through A match-case made from bamboo is water- tight and will not sink if dropped overboard the hollow portion about four inches above the ring. The ring forms the bottom of the cylinder, and the open top can be made water-tight with an ordinary cork. This kind has the advantage over the metal match-safe because it will float if accidentally dropped over- board.—L. B. ROBBINS. Lengthening the Supports to Increase Tomato Crop T is usually necessary to attach a vertical extension to a large number of stakes in the tomato patch at certain stages of growth. The extensions are -first prepared by driving wire nails into them, so that the points of the nails are flush with the surface of the opposite side, as in Fig. 1. Each piece is then fitted into position and held by an ordinary iron clamp, as |) EXTENSION Fg | FLAT im (reeset world by means of lengthened supports in Fig. 2. Holding the edge of a flat- iron against the bottom stake will steady the support while the nails are driven through and clinched. This device will help in getting every top stick ‘‘plumb.”—JAMES M. KANE. Peta 55 eee

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S One lowa rough water- rboard inches of the > made rk. e over it will over-. rts to op tach a 1umber certain ired by hat the ith the . Fig. 1. osition Amp, as UPPO™. a IG3 9 in the ipports f a flat- ke will ails are ig every KANE. May, 1919 A Chain Made from Ordinary Paper-Clips STRONG and pleasing-looking A chain can easily be made out of i hown in wire paper-clips of the type s the ‘linstration. Bend over the ends Paper clips will make a novelty chain which is made practical by bending the clip ends A and B into the shape shown in C and D. Of course, two links must be joined together before starting to bend the ends.\—JAMES M. KANE. Making Overhead Shaft Oiling Safe NE of the most important jobs in a machine-shop is the oiling of overhead shafts, such as line bearings, counter-shaft bearings, loose pulleys, etc. At its best, it is a very dangerous job. It is usually done with a long- This kind of oiling apparatus is an improvement over old oiling methods spouted oil-can and the help of a cumbersome ladder. The illustration shows a better and saner method of oiling. Attached to the oiler’s back is an air-tight box filled with oil, a hand-pump on the side supplying sufficient pressure to enable the oil to flow up through the rubber tube into the copper nozzle and from there into the machinery being oiled. The ladder is self-explanatory, and may be adjusted to any height by a simple raising or lowering of the pin seen under the man’s feet. This device will save time and labor, aside from the consideration of Its invaluable “safety first” prin- ciples.— WILLIAM KOoELPIN. Speed and Rat- chet Adjustments changedat a finger touch and without removing drill from work. Speed Shifter at hub of crank; Rat- chet Adjustment shown’ between small gears. NOTE: “YANKEE” Ratchet Hand Drill No. 1530, weighing only 20 ounces, has the same Ratchet Ad- justments as thc “YANKEE” Ratchet Breast Drill. yry\\s The Drill That Cuts “Coming and Going” Holes can’t be drilled in advance and carried in the tool box like other “spares.” But you can drill holes with the “YANKEE” Ratchet Breast Drill, when and where wanted, even in places inaccessible to other tools. It has two speeds and five adjustments: (1) Plain Drill; (2) Left-hand Ratchet; (3) Right-hand Ratchet; (4) DOUBLE Ratchet; (5) Gears locked for changing Pe or drills. a | Now suppose you must drill for a new at- tachment; drill out a broken bolt, or drill for some other repair where there is not sufficient af space to turn the crank of a common drill. Don’t waste an hour tearing down the job, but go right in after that hole with a “YANKEE,” first setting your adjustment for “DOUBLE Ratchet.” Even if you can only move the crank to and fro an inch, the drill turns forward continuously, cutting the same as if a full turn of the crank could be made. “YANKEE” Ratchet Breast Drill Price $Q75 No. 1555. Length 17 in. Three-jaw chuck for round shank drills up to 14 in. diameter. No. 555. Length 1714 in. Two-jaw chuck for holding both rounds and squares. :; ; Your Dealer Can Supply You Write for free ““‘YVANKEE” Tool Book, illustrating “VANKEE" Tools in action doing work that common tools cannot do; Bench Drills, Chain Drills, Ratchet Tap Wrenches, Removable Square-finished Vises, Plain Ratchet and Spiral-Ratchet Screw-drivers. North Bros. Mfg. Co., Philadelphia ia Cows og

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Make Your Writing 7-a-l-k! Just as oratory puts the power of em- phasis into the spoken word, so the— IMOND *" EVRITING MACHINE”’ —puts the all-telling power of emphasis into the writien word. other typewriter turns cold type into living, breathing words —words pulsating with the writer’s deepest con- victions—-words expressing to a nicety his most . conventional mood —words showing always absolute correctness—in busines, profes- sional or social usage. The business man who uses the Multiplex can put character and individuality into his letter, and can empha- size the important parts by changing in- stantly from one style of type to another. Note the six distinctly different type-styles reproduced in this advertisement. : The mail order man can put the same emphasis on the selling points of his product as he would in talking. ‘Just turn the knob” and you can change from commercial type to italic, giving emphasis when and where you want it. The Lawyer who swayed judge and jury by his eloquence can write his brief on the Multiplex so that every telling point scores with the judge. dhe author can prepare his manuscript so that no climax or no subtle point will be lost—can see his story practically in print before it goes to the publisher. Multiplex is unlike other typewriter It is revolutionizing typewriting. Its work is as» great an improvement over the typewriter as the earlier typewriter over the fountain pen, or the fountain pen over the quill. Just think of being able to choose from over 365 different type-sets, including all languages! The Multiplex is typewriting perfected to the art of fine printing and engraving—plus personality. Maii Coupon for FREE BOOKLET 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 fullness of your argument—how you can write with the same convincing force that you use in speaking— an exclusive feature of the Multiplex. We will also send our pamphlet, ““The President and His Typewriter.”’ Also—a PORTABLE Model For Traveling—for Home. Weighs about 11 lbs. Full capacity. Ask for special folder. No The any Write your name, address and occupation below and mail to— HAMMOND TYPEWRITER CO. 639 E. 69th St., New York City SE ee ee BIG PROFITS forYou inHB BATTERY CHARGING Start now to build bi tunities best this seaso new Fords with storage batteries. easily clearing $100 to $200 Extra Profit Every Month Some even more. Get in the game! This HB 7- Battery Charger recharges 1 to 7 auto batteries at once. Current cost 12c to 15¢ per battery. Motorist pays 75c to $1.50. Figure your profits, Noelectrical or mechanical experience re ed to operate. No expensive renewals or adjustments. $25 Puts Thie Money-Maker in Your Garage on Money-Back Guarantee Balance in 9 monthly payments of each. Earnings easily pay for AF Pin your $25 initial payment check to this ad and send i g battery business. Oppor- m—more old cars driven— HB use 8 are Guarantee. Don’t delay. Get those profits! elay. Get busy! HOBART BROS. CO., Box S5,Troy,O. Successful manufacturers since 1893 YOU NEED A MOTORCYCLE Secure one at small cost by put- ting a STEFFEY MOTOR on your wheel. Thoroughly PRAC- TICAL and RELIABLE. Made by the oldest manufac- turers of motor attachments. Send stamp at once for lowest factory prices. STEFFEY MFG. CO. Dept. S, 5025 Brown St., Philadelphia, Pa. A Cheaply Constructed Arc- Type Soldering-Iron ig ansagees form of arc soldering- iron operating from a 6-volt, 60- ampere storage battery that can be cheaply constructed will often be found of value. It consists primarily of a holder made as shown in the illustration. A strip of brass 1% in. wide, 1% in. thick, and 8 in. long is bent at its center around a form 1% in. in diameter. Holes are then drilled through the brass strip near the loop thus formed, in order to pass a small bolt used to clamp the carbon electrodes in place. The other ends of the brass strip are driven into a wooden handle after a heavy lead has been soldered to them. This lead is made from a 2-ft. length of twisted lamp-cord, using the con- ductors in parallel. A lug can be pro- vided at one end to attach the holder to the storage battery. A second lead is also provided with a lug for attaching to the battery, and the other end bared to make connection with the work being soldered. To use, insert a short length of hard carbon in the loop at the end of the holder, and connect the lead to one pole of the storage battery. The work tobe soldered is connected to the other pole by wrapping the bared end of the wire around it close to the point to be soldered. After cleaning the joint and applying the flux, take the tool in the right hand STRAP IRON CARBON wail i 4 = STORAGE BATTERY As efficient as the manufactured article is this home-made soldering-iron which utilizes the storage battery’s current and a length of solder wire in the left. Touch the carbon point to the work and withdraw it slightly to start the arc. The metal will be heated almost instantly to the melting-point of the solder, and the latter can then be applied. It might be thought that this short circuit would damage the storage bat- tery, but such is not the case. The usual amount of current used is thirty amperes, and at this rate it would re- quire nearly two hours completely to discharge the battery, whereas the tool is seldom in use for more than a minute. The amount of current required varies with the work in hand. Light articles require about ten amperes, heavier work more. The current can be regulated by connecting the lead to the work farther away from the point of contact.—THOMAS W. BENSON. 104 Popular Science Mg e | IXONS Quick Thinking Demands Quick Writing Whether in Writing, Account. ing or Drawing, the pencil which |. most easily and quickly records | your mental processes is Dixon's Eldorado, “‘the master drawing pencil,” In the 17 perfect degrees of hard. ness and softness you are assured of a pencil that will make your pencil. | work a delight. Leads, strong, re. sponsive, and long wearing, The Eldorado makes for genuineeconomy, Made in 17 degrees. 6B (softest to 9H (hardest), HB (medium) * general use. Get a trial dozen from your dealer, or send 15¢ for our grade chart and 3 full-length pencils worth double the money, Please mention your dealer’s name and the nature of your pencil work, ee: . Joseph Dixon Crucible Co, Established 1827 Dept. 120-J Jersey City, N. J. Canadian Distributors eX A. R. MacDougall & Co., sat Voaes Ltd., Toronto, Ont. Thereisa Dixon-Quality pencil, crayon, and eraser for every purpose WHET @H-/Pved Sumeup sajsew ay =, (\QWVUOUTA., SNOXIa Q High School and College Students—Attention! If you were told that you could earn your college expenses would you be interested? Would the testimony of hundreds of students who have done so convince you? Do you want to earn a scholarship of $250 or over during the coming summer vacation ? We have helped hundreds of students. We can help you. Write today for our booklet “Victory.” Review of Reviews Scholarship Fund 31 Irving Place New York, N. Y. ——_ Most Perfect Hearing! “THERAPHONE” Scientific Receiver Earpiece can’t confuse. Improves the he q 3 ae and absorbs the abe for Dusy, Geat, nervous, D) ivacy and noise. Abates attachments. Guaranteed to suit. (Check oF ’.0.D.—delivered). For Foreign Delivery add 20c. The Fvolution Phone Cow 48 Greenwich Ave., New York City

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May, 1919 Oiling the Crank-Pins of an Automobile Engine HE adjustment of the connecting- TL rod bearings is one of the most common repair jobs on an automobile engine. Probably the chief reason why these bearings wear faster than the others is that they are not lubri- cated properly under all conditions. The system described below has given very good results and has al- most eliminated connecting-rod bear- ing trouble. Most of the oil delivered to the main bearings escapes the ends and flows along the crank webs, and is finally thrown off by centrifugal force. If gmall scuppers are placed at the ends of the crank-pins this oil will be caught and may be carried through the pin to the bearing. In the right-hand illustration one throw of the crank-shaft is shown with the scupper in place. The oil Connecting-rod bearing adjustment is one of the most common yet compli- cated jobs about the automobile engine ‘ leads are indicated by dotted lines. The radial hole should be drilled first, and should extend to the center of the pin. Then a hole should be drilled through the center ot tne pin until it connects with the radial hole. The smallest drills possible should be used; probably an %-in. radial hole and a 3/16-in. lead will work out best in the average engine. In very large engines a slightly larger hole would probably give better results. In a case where the crank-pins are hollow, the scup- per placed over each end and over the radial hole is all that will be necessary. The other illustration shows a de- sign for a scupper that is well adapted to most crank-shafts. Sketch A shows the layout or pattern, B shows a side view, and C an end view. Sheet brass or copper should be_ used. The end of the shaft should be smoothed slightly, and then the scup- per riveted or brazed in place. The crank-shafts are carefully balanced in high-speed motors, so care should be used not to change the balance any more than necessary. Before installing such a system a careful inspection should be made, to make sure that there is room for the scuppers at all places as the shaft revolves. Great care should be ex- ercised in laying out this work, as the crank-shaft could easily be damaged, and in a job of this sort mistakes are very costly, usually necessitating the _ purchase of new parts. A study of the engine’s interior is essential to every amateur motorist.—S. E. GIBBS. | ae we we Go OS OS & & ae ae te & Se we SO ee ad Direct From the Factory to Save You $43 New Oliver Typewriters for nearly half what they used to cost. Latest and best model. Sold under a new money- saving plan. Five days’ free trial. No money down. The Oliver Typewriter Com- pany now sells by a new plan. During the war we learned that it was unnecessary to have great numbers of traveling salesmen and numerous, ex- pensive branch houses through- out the country. We were also able to discontine many other superfluous sales meth- ods. You benefit by these savings. We offer the exact $100 ma- chine—not a change has been made. Such is the guarantee of a $2,000,000 company. If any typewriter is worth $100, it is this splendid Oliver Nine, our latest and best model. Free Trial Merely mail us the cou- pon and we will send you an Oliver for five days’ free trial. Try it at your office or at home. If you decide to keep it, pay us at the rate of $3 per month. If you return it, we will gladly refund the outgoing transportation charges. Old machines are accepted in ex- change at fair valuation. The Oliver Nine has the stand- ard keyboard. So any operator may turn to it without hesita- tion. And it has a dozen other features which attract. It is greatly simplified in construction, far fewer parts. It is noted for its freedom from trouble, great durability and easy operation. Why be Wasteful? Whether you use 1 typewriter or 100, this new Oliver plan saves you half. No machine does better work. No typewriter is speedier. None are more satisfactory in the long run than the Oliver Nine. All this you can know for your- self very easily. You are your own salesman and decide for yourself. Read the coupon. Note how simple our plan is. Then mail it today for either a free trial Oliver or our amazing book entitled ““The High Cost of..Typewriters—The Reason and the Remedy.” With the latter we send an illustrated catalog describing the Oliver in detail. Which for you? Check one or the other item on the coupon now. Canadian Price, $72 The Oliver Typewriter Co. 1105 Oliver Typewriter Bldg., Chicago, Ill. (104.04) ee eS ee ee —_— = we ecru t THE OLIVER TYPEWRITER COMPANY i Pi 1105 Oliver Typewriter Bldg., Chicago . Ship me a new Oliver Nine for five days’ free 2 L] 4 $57 at the I inspection. If I keep it, I will pay @ rate of $3 per month. The title to remain in you a . until fully paid for. My dipping palin’ U. o..o0 sx scanctseiniokSatevacs This does not place me under any obligation to buy. If I choose to return the Oliver, I will ship 1 B it back at your expense at the end of five days. 4 a Do not send a machine vntil I order it. § Mail me your book—‘‘The High Cost of Type- I. writers—The Reason and the Remedy,” your de i 1 luxe catalog and further information. 4 Name.......ccccccccccccccccccccccccccesescosces i § Street Address...........ccccccccceseccccessees I I Clty, wceccccccscccccves State..ccccccccccsccecscs t ; anne TLR EE

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Study these microphotographs! A—New ordinary steel needle. ~ . B—Ordinary steel needle after playing =~ one record. Note the worn point! “. —New Sonora Semi-Permanent Sil- ~~ vered Needle. Note that the paral- “ee lel Sides (which are not tapered) always fit record groove perfectly. D—Sonora Needle after playing one record. No perceptible wear. E—Snonora needle after playing over fifty records. Needle has worn down, but is in splendid playing condition. Preserve Your Phonograph Records Sonora Semi-Permanent Silvered NEEDLES replace steel needles! They play 50 to 100 times and are used on ALL MAKES of steel needle records. Unequalled for convenience, economy, improvement of mellowness of tone and the increasing of life of the records. . Loud—M edium—Soft 30c per card of 5. In Canada 35c. FREE! ah See Needle will be sent request. Write for it. Sonora Phonograph Sales Company, Inc. GEORGE E. BRIGHTSON, PRESIDENT 279 Broadway, Dept. Z., New York Toronto: Ryrie Building CAUTION! Beware of similarly con- structed needies of inferior quality AN EASY WAY TO MAKE MONEY -22:: -on a small salary. Be independent. Go in the tire re- ing business. One man says ‘‘I made $60.00 the first y.’’ Others average KS $500 a month. ‘Very little capital needed. Jobs plentiful. Every motorist a pos- sible customer. No experience We teach you. SHALER Tire Repair Outfit ingot Wrapped Tread Method E ised by Tire Manufacturers Peeaegeet ao 5 Ge high [ie priced vulcanizi outfits. 4 boy (¥ st See ean use it. It’s the only vulcanizer PY that has Automatic Heat Control, and ean’t undercure or overcure a tire. es no W ing or 4 **How to m a Tire Repair Shop.”’ It tells ws to make tig money. Don’t delay. Write quick. C. A. SHALER CO. 2104 Fourth St, Waupun, Wisconsin Strong Knife Wire Pliers LeatherPunch Hoof Hook G Tools SwedgingAwl Wire Cutter Screw Driver Screw Bit Alligator Wrench Each a strong, practical tool. As easily carried as a 3-blade knife, and has nomore parts. af Length, 4in. Pliers and wire cutters are drop-forged tool steel—cut barbed fence wire as easily sed gy gall re Rear ers 8 . ‘wor om aise ostiten'e 34 independently. Electricians Railway Men Mechanics Horsemen Elican YX Wunderknife Motorists Sportsmen Sent postpaid in U. S. for $1.75 (add 5c if insured). Highest quality construction, fully guaranteed. Pocket Tool Chest : Charging Storage Cells from Service Mains — By Peter J. M. Clute HERE cells are employed for portable purposes, some convenient method of charging them from the ordinary supply source must be pro- vided. The method selected will depend mainly on the available charging current source. Alternating current, as such, cannot be used for charging, and when it is the only available source of power, some auxiliary means ‘| -must be installed for converting it into direct current. This can be accom: plished by the use of a motor-generator set, or arotary converter, or a mercury- vapor arc rectifier. If the available source is the 110- volt d.c. lighting circuit, connection can be made as shown in Fig. 1. It is advisable to connect an ammeter in the circuit, although this is not necessary. In order to limit the charging current to its proper value, lamps are arranged in series with the cells to be charged, the number of lamps necessary depend- ing both upon the line voltage and the rate of charging of the cells. A 16-c.p. 110-volt carbon lamp has about 220 > aa NOV. D.C. | | Switch heete- 32 ¢.p. lamps ® 0 0 O O Storage battery a - £ Ammeter all Fig. 1 An ammeter can be connected into the 110- volt circuit, although it is not necessary ohms resistance and will carry 0.5 amperes; a similar lamp of 32 c.p. rating has about 110 ohms resistance and will carry 1 ampere. Therefore, by connecting five 32-c.p. lamps in parallel, a charging current of about five amperes can be maintained from a 110-volt supply. . If the supply pressure is 550 volts, the charging current can be limited to, say, 5 amperes by connecting in parallel five series of lamps, each series containing five 32-c.p. lamps, as shown diagrammatically in Fig. 2. In both cases, of course, two 16-c.p. lamps in parallel could be used instead of each 32-c.p. lamp. In case it is desired to charge at a lower rate, fewer lamps will be found necessary, with the time for charging increased proportionately. Lamps form a very convenient means of adjusting charging current, but an adjustable rheostat is fre- quently used, as shown in Fig. 3. This resistance should be such that some of it can be cut out as the voltage of the cells increase, and it must be made of wire large enough to carry at Elican Specialty Co. ®7° Mejchants, Sank Bids. least 5 amperes with overheating. 105 Popular Science Month, Charging with pe. sistance in series jn. volves a large loss of energy, but in the case of small portable cells this waste is not a very serious matter, especially as the use of the series-resistance congtj. | | | Switch.” Fuses— 32 ¢.p. lamps 550 V. D.c. — - © 0 © mM © 0 © « ) ® © ° « ammeter : 9 oO ¢ ®o © ¢ Storage battery - + ui Fig.2 By connecting in parallel five series of lamps the charging current can be limited in amount to 5 amperes tutes the most convenient and simple means of charging from existing supply mains. The charging voltage must always be greater in value than the discharge voltage of the cell being charged. The charging current should be so con- trolled that the charging shall be at the normal eight-hour rate. Charging cur- rent must always flow through the cells from the positive pole to the negative pole, namely, in a direction opposite to the direction of flow of the current on discharge. When there is any doubt as to the direction of flow of current, a test should be made to ascertain whether + 0.C. Supply mains _Adjustable “resistance Storage battery Ah Fig.5 : | « Switch --... Ammeter A rheostat is very often used as a convenient means of adjusting the charging current the positive plates are connected to the positive pole, so that the charging current flows in at this pole. The most convenient method of testing the . polarity is by means of a voltmeter, which will give a scale deflection only in cases when the positive side of the line is connected to the terminal marked. A careful adherence to the above instructions will result in .a maximum amount of current in the cells. et tate ei pee ee i ie” Geen ee

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SOV. D.c. [ways be ischarge d. The sO con- ye at the zing cur- ugh the to the lirection w of the s to the , a test whether upply mains djustable esistance onvenient x current ed to the charging Che most ‘ing the . oltmeter, ‘ion only e of the terminal re to the lt in a3 t in the May, 1919 What a Pocket Mirror Will Do SMALL dessert glass, tumbler, or A wine goblet is held up by a per- former and seen to be empty. Re- moving a silk handkerchief from his preast coat pocket, the performer shows that it also is empty. He covers the glass with the silk for a moment, then withdraws it and puts it pack into his breast pocket. In the glass will be seen reposing a five-dollar pill, a small American flag, or any object the performer may fancy. This trick is made possible by using a mirror glass. A mirror is cut to fit inside the glass so that it can be placed in the center in an upright position. In fact, the performer may use two mirrors fastened back to back with strong glue, only a small piece of cloth separating them. The cloth is al- lowed to protrude just a fraction over the edge of the cut mirror. This pre- vents the mirror from “talking”? when it is pulled away from the glass itself. The audience cannot see the flag because the mirror makes the glass appear empty The bill is crumpled up and placed behind the mirror which is set in the middle of the glass. Looking into the tumbler, it appears empty, because of the reflection in the cut mirror. The affair is then covered with the silk handkerchief, and the two forefingers noiselessly lift out the mirror when whisking off the silk. This leaves the hill, which expands to fill the extra space created. Should anyone wish to examine the handkerchief, the performer can safely pull it out of his pocket and show it, for the mirror is so heavy that it will have slipped to the bottom of his pocket. A cut-glass tumbler is preferable, and the fitting of a small mirror is not difficult, as only a rough cut is neces- Sary.— MERRITT HALE. | and Real ‘At Last—A Real bed Money!” “And if only I’d started earlier, I could have had them five years ago. study would do for a man. I didn’t realize at first what spare time Taking up that I. C. S. course marked the real beginning of my success. In three months I received my first promotion. But I kept right on studying and I’ve been climbing ever since.” Every mail brings letters from some of the two million students of the International Correspondence Schools telling of advancements and increased salaries won through spare time study. How much longer are you going to wait before taking the step that is bound to bring you more money? Isn’t it better to start mow than to wait five years and then realize what the delay has cost you? One hour after supper each night spent with the J. C. S. in the quiet of your own home will prepare you for the position you want in the work you like best. Yes, it will! Put it up to us to prove it. Without cost, without obligation, just mark and mail this coupon. ee en oe en oe TEA CU ommee meee mee m INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7634, ee PA. the position, or in the subject, before which i mari X- ELEOTRICAL ENGINEER Window Trimmer 14 Telegraph Engineer Show Card Writer Telephone Work MEOHANICAL ENGINEER Mechanical Draftsman Machine Shop Practice Toolmaker Gas Engine Operating CIVIL ENGINEER Surveying and Mapping MINE FOREMAN or ENG’R STATIONARY ENGINEER Marine Engineer Ship Draftsman ARCHITECT Contractor and Builder Archite ctura! Draftsman Concrete Builder tructural Engineer PLUMBING AND HEATING Sheet Metal Worker Textile Overseer or Supt. CHEMIST Teacher Sign Painter Railroad Trainman ILLUSTRATING Cartoonin: BOOK) ER Stenographer and Typist Cert. Pub. Accountant TRAFFIC MANAGER Railway Accountant Commercial Law GOOD ENGLISH School Subject Mathematics CIVIL SERVICE Railway Mail Clerk AUTOMOBILE OPERATING Auto Repairing Navigation AGRICULTURE Poultry Raising Spanish French Italian | Name. Present oO tion Street and No. | City. State. Canadians may send this coupon to International Corresvondence Schools, Montreal Canada “ I 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 i+ slip by, Mark and mail this coupon now. 107 Big 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 as now. -_——_—— — — TEAR OUTHERER =o = = INTERNATIONAL 7 GORRESPONDENCE SCHOOLS Scranton, Pa. Explainfully about your Course in the subject marked Xs ELECTRICAL ENGIN’R §C)Telephone Wor! ADVERT’S'G ELECTRICIAN Mechanical Engin’g §_J/BOO KE’ PG ELECTRIO WIRING Mechanical Draft’g Stenograp’y ELEOTRIO LIGHTING Civil Engineering Civil Service ELECTRIO RY. WORK Stationary Engin’¢ AUTOMOR'S ELECTRICAL DRAFTS'N Mining Engineer’g Ship Draft'g ELEC. MAOH. DESIGN’R ¥_JARCHITECTURE CHEMISTRY TELEGRAPH EXPERT [CJArchitect’l Drafting IC )Farming Name Address.

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VoSAVED & GET OUR 1) 31¢ BOOK, YOUR DO%s's PLUMBING AT LOW COST & HEATING « Send for our big instructive 256 ge well- bound Handy- Man k 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, Ho’ " Air, Water or Steam plant. 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 this valuable 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 25¢ which we refund on first order, or we send our Bargain Bulletin FREE. Address Today _ Hardin-Lavin Company 40 years at ' 4526-368 Cottage Grove Avenue Chicago $500,000.00 plants behind our guarantee "More Power—Greater Speed !| The KOBAN will “runaway” from any other rowboat motor because its two cylinders produce more power. In every way, it isthe motor for the man who demands real service and efficiency. The KOBAN does not shake the boat, because : 5 both cylinders fire at the same time, neutralizing the shock. The Great 2-cylinder KOBAN ROWBOAT MOTOR Only by this 2-cylinder opposed con struction can you avoid the vibration that makes riding disagreeable, opens seams and ruins rowboats. Special tilting device for shallow water and ching. For com- mercial St rk the KOBAN is unequalled. Used by U. S. Government and in 36 foreign countries. We age doe nee os an wheat spans for Civeuar 80 80 tells ali about it. KOBAN MANUFACTURING CO 299 South Water St., Milwaukee, Wis., U. S. A. MAKE YOUR BIKE A MOTORCYCLES - ws Used His Four Years”’ Harry A. Hyatt, of Boreas River, New York, writes: *‘About four years ago YY attachment, and wish to say thal I am satisfied with it in every way, for it has certainly given me good service. Anyone wanting a poe or attachment, I would rec- mend them to the Shaw Manufact- coring Co.” write ee ootee for bargain FREE BOO tree booklet. fully describing the: sta Taleyete Motor At- tachment otoreys eo es ~4 ae. new and a Fs at a small cost, by using our attachable outfit. Fits any a tee Easily at- SHAW MANUFACTURING co. SIMPLE way of carry- ing automobile cur- An Easy Way to Carry Emergency Automobile Curtains LOOPS SCREWED ON Popular Science Monthly : case of a sudden storm, and prevent the celluloid tains so that they may be available in a jiffy is shown in the illustration. Hame loops are screwed into the rear arch of the top, and the curtains are rolled up and strapped into place. These loops keep the cur- tain within easy reach in WELL known method of iright- ening birds away from the garden is to tie corks along a string stretched the length of the field and just above the young plants. Feath- ers are stuck in the corks, so that the faintest breeze will cause them to move and thus frighten the birds away. But birds frequently feed in the early morning and late evening, when there is usually no breeze. That which frightens birds, animals, and human beings most is the sudden mechanical scarecrow is but -intermittently, suddenly, unexpectedly. Curtains carried like this will always be clean and smart looking or unexpected. .The success of the that he waves his arms, not continuously, and De:-t. 169 GALESBURG, KANSAS . Running water is the motive power that pulls the string and causes the scarecrow to wave its arms. The string-pulling mechanism consists of two pieces of narrow board mounted upon hinges. At opposite ends of a box, at a slight angle, the water bucket—which might be a paint-can, as shown in the center illustration— is mounted by wires that hold it se- curely. On the opposite end is fastened a piece of pipe or some other object 108 windows from cracking, Every one has seen the yn- sightly yellowed and crack. ed windows that the average automobile boasts of. This : carelessness not only de- tracts from the car’s beauty but also from its gale price.—C. L. MELLER. A Mechanical Scarecrow By Raymond V. Wilson that will act as a weight to counter- balance the weight of the empty bucket. An upright is mounted on this board, to which is fastened the string that pulls the scarecrow’s arms. On the left-hand hinged board are mounted the trigger and a can weighted with rocks. This weight and the trigger prevent the bucket from dip- ping before it is filled with water. When the bucket is full, its weight overcomes that of the can of rocks, Here’s a practical and automatic way of assuring yourself that birds or animals are not destroying your garden vegetables and crops which it lifts. The bucket arm then slips past the trigger, allowing the bucket. to dip and pull the string which will wave the scarecrow’s arms. The bucket, having discharged its contents, is no longer heavy, and is drawn back to its original position by the “‘bird-cage”’ spring seen at the right top of box. The scarecrow’s arms will also assist by their weight. The bucket arm slips back past the trigger, and is held in place by it until the bucket fills again. The size of the stream of water flowing into the bucket determines the frequency of the scare- crow’s antics. Three or four times a minute ought to frighten away the. boldest bird or animal.

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es PaeorT rar na & ae Pee a7 © are fed the ip- er. tht ks, then the tring rms. 1 its 1d is n by the “Ow’'s ight. ; the until f the icket care- nes a y the. May, 1919 The Invaluable Automobile Jack HAT little jack stowed away under i the seat of your car will do many helpful things, but three more of them, of different sizes, will save you much time and temper. For instance, when you get hope- lessly stuck in mud, sand, clay, or even snow, your jack may be the means of getting your car out of its predica- ment and save you that six-mile walk to the nearest village to get a span of horses. ; Every jack should be fitted with a 9-in. block of wood as broad and long as will conveniently fit into the car. If the jack is so equipped, it will allow the car to be jacked up out of the mud- hole, so that the rear wheels can have FRAME STRAIGHTENED BLOCK Do not neglect to increase your jack family by at least one or two before taking a tour boards slipped beneath them for trac- tion. If necessary it is not a bad idea even to use the car cushion for traction; that is, if no planks are at hand and you are hard pushed for the necessary material. In fact, anything that will enable your car to get on solid ground is cheaper than waiting all night for assistance. One of the cleverest uses for the jack was seen recently, whena wounded soldier drove into town in a heavy car that had a broken spring. As he had a crippled leg, he was not strong enough to lift the body of the car to place a bumper or log between the axle and the frame. But he had wisely provided himself with a small low jack which conveniently fitted into the space between the axle and the body. The jack is indispensable during the spring overhauling or when there are bent parts to the body or frame. For example, bent body parts may be straightened by giving the jack a leverage against the garage wall, working the jack against the wrenched part. Jacks have long been used in garages that are not equipped with huge machinery for straightening bent frames and even front axles. In addi- tion to this, when straightening a bent _ frame with a jack the chassis does not need to be dismantled, as it would if missed—not the smallest detail. . Shop Work, oe Shop Kinks, ear Cutting, cy xpiain Lathes and Screw Machines, Planers, Millers, Jigs, Shop Management, Metallurgy, Weld- ing, Die Making, Laying Out Dies, Tool Making, High Speed Steel, Thread Cut- ting, Milling Cutters, Punch Work, Tool Design, Foundry Work, Molding, Malleable Practice, Forging, Heat Treatment of Steel, Annealing, Hardening, Pattern Making, lime and aHalf For Straight Ti OU can get an extra half dollar or more for every , you earn now. No overtime work is necessary. Just your regular time and a set of Modern Machine Shop Practice Work will turn the trick. Read how to get these famous books written by 27 shop experts that will help you make three or four dollars with the same effort it takes you to get two dollars now. Machine Shop Practice 6 big volumes bound in genuine American Morocco. 2300 pages and more than 2500 photographs, plans, drawings, etc. These books explain and tell you everything connected with Shop Work; more than a thousand different subjects. Not a thing is They cover everything, from the simplest machine operation to the most difficult tool and die making propositions you will ever be up against. They will make a shop expert out of you in your spare time and it will only cost you 7 cents a day to buy the books after a weeks’ free use. With f these bookewegive ASK Our absolutely free, one EXPERTS years’ consulting membership in the American Technical Society. It usually sells for $12.00. This entitles you to write in at any time within a year and ask our experts’ advice about anything connected with shop work that you don’t understand. Use One Week Mechanical Drawing, Design of Machines, Auto, Shop Work, Machine Drawing. e Don’t send any money. Just the coupon is all you need. We will ship the books express collect and you can use them a whole week in your own home or shop just as if they were your own. ‘Try to find some tough proposi- tion they won’t explain. Show them to the other men in your shop—give them every test you can think of and send them back at our expense if you don’t want to keep them. If you do want the aaats books to help you earn more, like thousands a ay of other men_ have done, send us only $2.00. You can send the balance of our special $19.80 price the same way —$2.00 each month. Begin now to get ahead—do it the speedy way,t0o. This coupon is’ your ticket on the speedy route. MAIL IT TODAY. AMERICAN TECHNICAL SOCIETY Dept. M-1205 Chicago, Ill.. U. S. A. AMERICAN TECHNICAL SOCIETY, Dept. M-1205, Chicago, Ill., U.S.A. Please send me the six-volume set of ‘‘Modern Shop Practice’ for seven days’ examination, shipping charges collect. If I decide to buy, I will send $2.00 within seven days and balance at | $2.00 a month until $19.80 has been paid. Then you will send me a receipt showing that the set of books and the Consulting Membership are mine, and fully paid for. If I want to get along without | the books, I will return them at your expense after seven days. | O00 0.0 6 OS S086 OS OOOOH PS SOSPEDHR OC CODES CESU SEEKS KOC CCH OH C CEES OHO HOOKERS ODS 6696.00 CR OU Ore heat were applied.—G. F. CoLLINs. 109

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For Men in Every Walk of Life Here’s the collar that saves time and money—won’t- wilt and always looks neat. Challenge Cleanable Collars give you all the style, snap and comfort of Cotton Collars with the added advantage of being instantly cleaned when soiled. 35c each at your dealers or direct—state your size and style. Booklet on request. THE ARLINGTON WORKS Owned and operated by E. !. du Pontde Nemours& Co. 725 Broadway, New York EXITITIESIIIIIE SII a CThe MIRACLE of MILK Drinking Your Way To Health ‘ou know in a general way that milk is good for you. But if you knew what a precious life-giving fluid it really is—if you knew the almost miraculous results it luces for those who drink it intell Vv, you would ) be truly amazed. For anemia, indiges- tion, constipation, any difficulties of the stomach, liver, kidneys, heart or bladder, Bright’s disease, rheumatism and many other ills for which physicians have no i remedy, the right use of milk ale most invariably overcomes the trouble. For instance, feet and hands that are usual- ly cold and clammy, become warm and life-like a few days after beginning this marvelous eelf. Benarr Macfadd the famous physical culturist, in collaboration with Dr Sanford Porter, the milk diet special- ist, has written @ book of priceless value en titled: “The Milk Diet. How To Use It.” You May Have It Free It will bea revelation to you. Send us a six months’ subscription for PHYSICALCULTURE MAGAZINE at the regular price of $1.00 and will mail you the book at once. PHYSICAL ULTURE MAGAZINE should be part of your reading every month. {ts inspirational articles 7 on Health, Hygiene and Snocess-Building will be of great value to you in‘many ways. To more oadly circulate this unique magazine, we will 4 it to you for 6 months for $1.00and include t. Macfaiden’s above mentioned book free. Write TODAY. PHYSICAL CULTURE PUBLISHING CO. 119 West 40th St., Dept. 10A, New York City 19 DAYS FREE TRIAL reverse, etc. Looks, writesand wears like new. Try one for 10 days FREE. coe ony ween a ed. — ‘or cash. or earn one m plan. customers. 27 Our Sundry Dept. offers Needles 45c. per thousand, | $4.00 to $200.00 Retail in lots of 500,000. Motors $1.35 to $14.75 each. Tone Arms and Reproducers $1.30 to $5.75 per set, Main Springs 20c. to 90c, each. Records, Needles, Sap- | phire Points and Parts at reasonable prices. Write for our 84 page catalogue, the only one of its kind in America, illustrating 33 different styles of Talking Machines and over 500 different Phono- graphic Parts, LUCKY 13 PHONOGRAPH COMPANY Export Dept. 46G, E. 12th St., N.Y., U.S.A. ture camera illus- trated is made of parts that may be obtained at small expense. No effort is made to give actual measurements, as it may be easily built large or small, according to the camera at hand and the ideas of the builder. Regular motion-picture film is used in the camera, and may also be used for projection purposes or prints made from the negative, bound in book form, and thumbed to view the action. Remove the back of the camera to be converted, in such a manner that a wooden. shield may be fitted to the space usually occupied by the film or How the camera will appear when it is finished. Any size camera may be used plate. An opening exactly in the center 34 by 7% in. is cut in the shield, being the height and width of the lens. A wooden frame to be placed directly back of the camera is made in the shape of an H, the upper part of the H for the roll of film, the center for attaching the film-moving mechanism, and the lower part to guide the film back to thé take- up reel. An opening is made in the center of the wooden frame, the size being the same as the opening in the camera-shield, the openings to be opposite each other for the purpose of focusing, and, in case the camera is used as a projector, to allow the light to pass through the film. As the film must move exactly 34 in. to an exposure, it is better to use the than to. make it. The shutter of the camera used is left open, or means is provided for operating it from the outside of the box. The shutter is made of a circle of tin cut in half and attached to the drive-shaft so that the halves may be spread apart or brought together to compensate for the variation of bright ‘ and cloudy days. 119 Make Your Own Motion-Picture Camera mechanism for a toy projector rather - Popular Science M. HE motion-pic- By Leo Hirsh To time the shutter. with the film move. ment, two bevel gears are used. One gear is attached to the cam-shaft of the film-moving mechanism and the other to the drive-shaft of the shutter. The drive-shaft, to which the shutter is attached, extends outside the cam. era-box, and a wooden circle, which ig hollowed to inclose the shutter, jg fastened to the box. To time the shutter to the move. ment of the film, all that is necessary is to see that the opening in the shutter passes the lens opening after the film has moved, and that the shutter is closed while the film is moving. This may be done by setting the beginning of the opening of the shutter in front of the lens just after the cam that moves the film has brought the film down for exposure. It is necessary to have a film-meter to tell how many feet of film have been exposed. The one used in this camera was built by bending a wire in the shape of the letter L. The small part of the L rides the film, and the long part, extending through the box and the calibration, is marked off by running through one foot at a time, As the roll of film gets smaller, the indicating hand will move according to the position of the part that rides the film roll. The view-finder is made from a small camera, and, after attaching to the box, is marked to indicate the position of the subject on the film. The take- up reel is to wind up the film after the exposures are made, and is run by a belt Interior view of camera showing shutter- cover, shutter drive-shaft, film-moving mechanism, make-up reel, and film-meter from the cam-shaft. The wheels may be obtained from a ten-cent toy, spaced the width of the film apart, and large enough in diameter to hold the capacity of the roll of film used.

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May, 1919 Handy ‘‘Pick-Ups”’ for Small Work

\OVe- ELOW is described an easily con- One B structed pair of “pick-ups” for in- f the gerting or holding small parts of other machinery while assembling them. By the rounded portions in the center utter they are easily spread with the thumb cam- and finger and retain a firm grip. ch ig T, is iia ree nove. = ee , 40 BRASS pee u sa, tt al > film. 3 — jane VioiS|t |

er ig x This mee. nning ‘mf RIVETS | tf J Ce eo SO} noves , n for An improvement over the old type of tweezers, that must be con- tinually depressed and_ gripped

meter here The small filling block at the end ae is tapered, which, when the halves | pall are riveted together, —— points long in contact with considerable spring. d The points, or halves, are made of : t 3/16-in. steel wire drawn out at the ‘dane ends to 1/16 in. he For the air motor, automobile, and rs a 4 other small intricate machine assem- . idee bly they are very convenient, as the Bi points retain their grip, enabling the operator to accomplish much more ‘small than would be possible with other o the types.—F. W. BENTLEY, JR. sition -take- er the Ask Grand-Dad—He Knows “7 It’s True es HIS illustration of an old grind- stone and frame—particularly the frame—shows that the lack of a proper frame for the grindstone did not hinder

we ———————=S=—— FJ) — ee an N if —$——S— Oe ——- ——— ~ororrmrn IML LLLLLLLL AU: SS >)

The Red Signals [3 of Danger Ahead \|2

vad] Oh for the good old days when matter: nature supplied our simple wants! 10ving meter the early settler. He went out into the woods, selected a strong tree fork ls may of the right shape, and cut it down. spaced Then he bored three holes in it, in- d large serted the legs, and had what he apacity wanted.— James M. KANE.

[’ you were driving a locomotive at sixty miles an hour, you would watch out for every red light of warning along the track with an eagle eye; you would slow down instantly, as soon as you saw one; your own life and the lives of hundreds of others would depend on immediate action. Your life depends right now—and the happiness if not the lives of those dependent on you—on the way you drive your human machine along the railroad of life and watch out for and heed the red warnings of danger ahead, that Nature flashes before your eyes. Are you tired out before the afternoon is half over, unable to work quickly or think straight? That’s one of Nature’s red lights. Do you wake up in the morning feeling like a human wreck, and stagger through your daily work miserable with indigestion or biliousness, loggy with constipation, hacking and spitting from chronic catarrh—without an ounce of reserve vitality in you or any interest or ambition in your work? Those are WARNINGS of a smash up ahead, unless you take steps IMMEDIATELY to avert it. Keep Your Human Machine in Order You can’t make a success in life; you can’t advance or even hold your present position, unless you make your- self FIT and KEEP YOURSELF FIT. Everything depends on.it; every chance of happiness for yourself and for your wife and children; the kind of children you will have depends on it, there’s no getting away from the fact. No man’s physical and mental condition remains the same; if you are not getting better you are steadily getting worse and the smash up will come; it’s one of Nature’s inexorable laws.

Never mind what brought you to your present con- dition; GET OUT OF IT. I will help you, just as to- , 2 day I am helping thousands of other men, whose :@, vitality has been sapped and manhood lost by over- work, by inherited ailments, or by youthful errors and indiscretions of their own. BRACE-UP—take hold of yourself; get back your original snap and pep and punch —you can do it; I GUARANTEE that you can im- Strongfort is unquestionably the finest prove yourself 100 per cent., if you will only follow SS ee eee my directions for a few weeks. ; LIONEL STRONGFORT “Dr. Sargent, of Harvard, declared that

Strongfortism Will Keep You Running Right Strongfortism will build you up from the » oa beginning, strengthen your heart and lungs . and every other vital organ; develop your figure, round out your muscles, clear up CUT OUT AND MAIL THIS COUPON Mr. Lionel Strongfort, Newark, N. J. Dear Strongfort — Fl your book your brain and make you FIT. Strong- mg “PROMOTION AND CONSERVATION CF HEALTH, fortism is an embodiment of the natural methods by which I built myself up into the STRENGTH AND MENTAL ENERGY,” for pcstage of which I enclose three 2c stamps to cover mailing strongest man in the world without the aid expenses. I have marked (X) betcre the subject ip

of any druggist’s dope, and the whole secret which I am interested. 879 of it consists of Living Life as it ought to . Colds . . Insomnia . «Weaknesses be lived. And that always means getting . Catarrh - Short Wind - - Gastritis . A . Asthma . . Flat Feet . .-Heartweakness the greatest enjoyment out of it. . . Obesity . Stomach . Poor Cireulation . . Headache Disorders . .Skin Disorders Don’t wait—that’s what YOU want, and you can . . Thinness . .Constipation . .Despondeney get it if you stir yourself out of your lethargy and . .Ruptare . - Bilionsness . .Reund Shoulders go about it the right way. Indicate on coupon here- . Lumbage .. Torpid Liver . - Lung Troubles with your main ailment and send same to me prompt- . Neuritis . - Indigestion . . Increased Height lv with your reauest for MY FREE BOOK, . . Neuralgia . . Nervousness . .Stoop “Promotion and Conservation of Health, . . Flat Chest . .Poor Memory Shoulders Strength and Mental Energy;’’ it will tell you all . . Deformity . ._Rhenmatism ..-Mosealar about HOW TO GET IT. There's no charge for it; (deseribe) . -Bad Habits Development send three 2c stamps to cover postage and packing and I'll mail you a copy at once, also sending you B personal. private information and professional advice. NAMB. Fiscc ccccccccccccesccccscesccessagseaeeseeeane DO IT RIGHT NOW! LIONEL STRONGFORT Physical and Health Specialist 879 Park Building a Newark, N. J. OPET oo ccc cccccgecssccepencant Sr.

ee eee eee E reer)

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ile ag a a nl RR SRNR ie eR santos Tractor Busines AUTOMOBILE, Truck, and Tractor indus a try now entering its greatest period of develop- ‘ment and use. 80,000 towns and rural communities ‘without garages or repair shops of any kind. Inter- ‘community ck Hauling and Motor Mail Routes will require extensive maintenance. and repair shop facilities. High cost of 7 farm products making immense demand for farm tractors. Every man, 16 years of age and over, can qualify himself here to make big money as Motor Mechanic, or get into — for yourself and earn much more. We refer you avis age pcan Learn Here in 6 to g Weeks Earn $400 to $4060 a Month ks Immense additional equipment from Military Divis- ion of Rahe School. Same practical method as used to train thou- sands of Soldier Mechanics in 60-day courses. ay sane tional cost Yj arn part living expe FREE NOW Wie olay for Dey ‘TeialOfles and 6-750 | Rahe Auto & Tractor School xansas cir, ito. THE ANDERSON STEAM —— Get Every Day Service deus Sa Out of Your Bike eta erat aa te f full customary 1. i ; Ask us for fteratare and location of 4 ool, W. Have it always in A-1 running order. sos Srna oe ‘where 700 can a, Think. of all the good times you other makes and learn their method, then would have had IF—you hadn’t got a puncture, just when you were having the the most fun. You'll never know you have a puncture after you fix up your tires with a couple of tubes of of you or refund your mone course will cost you $20 i in either the +4 Our ‘ ee fany ime t thereafter . pay us 10) fend vu k ges bs aon oau canizer, your ‘ $235 and 5 to 10 days in Any Anderson f Vulcanizing will start youin s, th t table b TIRE FLUID = The Aad pron ie randy uN , i om rurereeneicre Ag a ae) Lee and get a cut in your receive many we can not make Popular Science Monthly a A Solid Square that Is __ Easily Made Ao solid square is a tool that. every mechanic takes great pride - in possessing, especially when it is ° of known accuracy. The advantage of the one shown in the illustration is that it may be adjusted to a perfect right angle at any time it is found to be si a CF o> - ee aA mi ph CASTE bee ra SS 8 32 4 hat! G*32 THD | 1! 1 rT B~2REQD Fi Ht i! | | img] | NOSZORLA HH “|| | B t \! ne oo) ri oa) ee in| | iH t { \! 1 t ho A " He foul ta Cc iH t r e ea B | =} tocol | . So Bly Ea — > KS 2 eS Fhe 6*32 DRILL & TAP — re, NEVERLEAK Al see | AGENTS 529,°/2 ES . PROFIT For store fronts, office windows and glass signs from the start. $30.00 to $100.00 a Week! Go to your dealer today and get two tubes of NEVER- Cents EAK, one for each tire, and put it into them Tas lobe nat one We LC N War Aeroplanes! Build a Model Acropiane th that will’Ay like a real one Scale nee and Building — iy. bail you can easily buil gxact Ott. _ duplicates of War-famous nd now for Drawings andi Instructions for the one you want a ras pgfan ped ii pee :. k . cS fet "Mononigne,, Niet Bie: c ®. E. Gunecher, A, A. M. Uo. j - sce Y . Monoplane, sone: "Gea kes a Wright Biplane. Cecil 1 Pin st Catalogue of IDEAL Model Aeroplanes each and Supplies, 5c. None Free. Postpaid Ideal Aeroplane & Supply (o.. cor. Houston and Wooster Sts., N.Y. SUPERIOR SINCE 1904) Over 100,000 in Use &f Golden Gem 4 ASsing Machine Pegommendation, vara ee fe esa Gold and Silver Sign Letters of allkinds. No experience necessary. Any- one can put them on and make money right You can sell to nearby trade or travel all over the country. There is a big demand for win- dow lettering inevery town. Send for Free _ the valve. It's 8 Pee to do and wees a, ee, * en you wherever you Loon for Signature ral er to General Agents. Satan tivar iat nese have METALLIC LETTER CO., 400 N Clark St... Chicago Buiitlo Specialty ayes se | Wy Build and Fly Model Buffalo, N.Y. Red Seal Dry Batteries Are Guaranteed to give absolute satisfaction for Automobiles, Motor Boats, Gas or Gasoline Engine Ignition, Medical Batteries, Telephone, Door s, Annunciators, Wireless Apparatus or any other open circuit work, ASK YOUR DEALER Send for Our New Edition of Our Catalog 428 It. will be pocket size, 8 x 4}4 and wil! contain 248 pages with over 1.100 illustrations, describing in plain, clear language all about Bells, Push Buttons, eng Telephone and Telegraph Material. Electric Toys, Burglar and Fire Contrivances, Electric Call Bells, Electric Alarm Clocks, Medical Geeten. Motor Boat Horns, Electrically Heated Apparatus, Battery Con- poston. Switches, Battery Gauges, Wireless Tel h Instr ts, Ignition upplies, etc. MANHATTAN ELECTRICAL SUPPLY COMPANY, | eh NEW YORK, 17-Park Place - CHICAGO, 114 So. Wells St. ST. LOUIS, 1106 Pine St. SAN FRANCISCO, 604 Mission St. Instructions should be followed carefully, .studying- the dia- . gram for the relation of parts out of tune; though with reasonable eare this defect should not often appear. The beam A and blade B should be made of a good grade of. carbon tool — steel well annealed. The beam has a 3/32-in. slot milled into one end to admit the blade, and two No. 52 drilled holes which the 1/16-in. die drill-rods pass through, used to hold ° the blade in adjustment. If trouble is encountered in drilling so deep a hole with so small a drill as. No. 52, the size may be enlarged to 3/32 or Yin. In this case it will be - necessary to change the size of the adjusting screws to No. 8 by 32. The pivot C should be made of tool. steel, hardened, and should be a light press fit in the beam, while the blade | ‘ Heat the blade in a clear fire to a me- dium cherry red to harden the edges should be a free fit on C and also have a small amount of clearance in the_ bottom of the slot in the beam when — it is assembled to allow for adjust- ments. Hardening the blade is not abso-~ lutely necessary, but of- course it * lengthens the life of-the tool. If this™ 112 method is to be used, however, le ©

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SY = ae OP iw YV Fee Ee (OOO QU

RESH air, good fishing—and a fleet Far “Old Towns” make a successful outing. Outdoor life made the brain and brawn that brought victory to our soldiers. Spend your vacation in the open, angling, shooting, exploring in an “Old Town” for the pleasure and good exercise it gives. “Old Town” Canoes are built light but sturdy to stand the strain. Speedy and trim. Why rent when you can own an “Old Town’? Send for catalog. OLD TOWN CANOE CO, 1895 Main St. Old Town, Maine

New Pleasures ° In Boating With a Lockwood - Ash Row Boat Engine new boat- ing pleasures are in store for you. On your vacation, camp- ing, fishing, picnicking or hunting, you can explore new fields. You can glide through the nar- rows, across the riffles, over the shal- lows. Young and old can enjoy this practical, economical sport. Ask for the Lockwood-Ash Booklet ; learn about the 30-day trial plan. LOCKWOOD-ASH MOTOR CO. 1951 Horton Ave. Jackson, Mich. im, <I (55)

OD=ASH| ERNE ED = NGINE $= \-\/ = 4

“DON'T SHOUT” “I hear you. I can hear now as well as anybody. ‘How?’ With THE MORLEY PHONE, § I’ve a pair in my ears now, but ey are invisible. I wo’ not know I had them in, myself, only that | hear all right. “The Morley Phone for the

is to the ears what glasses are to the eyes. Invisible, comfortable, weight- less and harmless. Any- one can adjust it.” Over one hundred thousand sold. Write for booklet and testimonials. THE MORLEY CO.., Dept. 797, Perry Bldg., Phila.

ROBINSON REMINDER AtAll live te IYfd, by , Robinson Mig.G Westfiela, Mass

procure four steel or cast-iron blocks, about 114 in. square and about 6 in. long, with one side of each of | them machined perfectly flat, -placing | two of them 34 of an inch apart, | parallel lengthwise, and with machined | surfaces upward. Heat the blade in a clear fire to a medium cherry red, and instantly lay it on top of the already placed blocks, being careful to have Y in. overlap on each, also laying the remaining two on top, exactly over the bottom ones. If this operation is done quickly and properly, the cooling properties of the blocks will be found sufficient to harden the edges and at the same time keep the blade flat. It will be necessary to grind the two parallel edges, for they will be more or less warped after the hardening is completed. There are several methods of setting a square to an exact right angle. A simple and very accurate way is to turn in the lathe a perfectly straight cylinder, and, facing one end to a bevel edge—using, perhaps, a piece of 214-in. die pipe or tube—produce a standard which can be used at any time to test the accuracy of the square—A. DANE. A Portable Tool-Box for the Repairman N engine-houses where locomotives are given running repairs, a ma- chinist necessarily needs some heavy wae:

A tool-box that will accommodate any number of tools and is not too heavy to be handled by one or two men tools and small parts such as cotter keys, nuts, washers, etc. If he had to keep these articles in a locker, a great deal of time would be consumed in going after the tool to do a certain job. Ifa machinist is furnished with a portable tool-box like the one illus- trated, he can take his tools and small parts from place to place very quickly. A box 13 in. high, 18 in. wide, and 38 in. long (outside measurement) is made from 1-in. lumber. On the bot- tom of this box are secured two pieces of 2-by-6-in. lumber, as shown. square pieces are fastened for slides, and across the front end is nailed apiece of 1l-in. lumber. A drawer is made and put in this space, providing facilities for small parts. Wheels are placed and a _ wrought-iron piece forged for a stand. Handles are made of pipe and se- cured to the sides of the box with pipe- clamps, allowing the handles to work free. A cotter-pin in the lower end prevents the handle from pulling out, and, being slightly expanded on the upper end, it is kept from dropping out. When not in use, the handles are pushed down out of the way. 18

On | the inside faces at the bottom, two 1-in. |

ws 1205, 1772 Wilson Ave., Chicago REP course

needed. Men who are masters of this profession are scarce. The de- mand for Finger Print Experts is great. As a special inducement we will give you . free of charge our new easy reading course in Secret Service Intelligence’ if you act at once. Be a Finger Print Expert Build up a business on the basis of a trained brain. You can doit as a master of the Finger Print profession. There is crying need for Finger Print Experts right - now and the demand for these trained men is growing every day. . A profession that offers wonderful opportunities for advancement. Governments, corpora- tions, police departments, institutions and individuals have constant use for these specially trained men. The work is fascinating and The Pay!s Big! No special education is necessary. You M “eee Finger Print. Experts are can become a master of this profession _ by studying at home in your spare time. Expert Finger Print men travel all over the country solving mysteries that baffle all others. They are important men and highly regarded and envied by every one. Mail the Coupon Get full information about this great pro- fession and our big offer of a free course in Secret Service Intelligence. The mas- tery of these two closely a'lied professions places a brilliant career within your grasp. Achievements that will immediately place the stamp of success upon you, are now possible. Send this coupon for full information NOW. University of Applied Science

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°90to'250aMonth bused blero) (Olly sen Trained. men are in big demand at good. salaries by the Signal De- partment of every large railroad in the United States. Today the opportunities are bigger and better than ever. RAILROAD SIGNAL MEN are urgently needed at salaries ranging from $90 to a month. The training necessary to get started in this fascinating work can be easily acquired at home a ge ambitious man, ‘ite Free Book. t all the facts before you, Learn about the big iti open thr e United States. Learn all about our big special free outfit. Write a letter or postcard or send coupon now. DEPARTMENT OF SIGNALING 1810 Wilson Ave., Room 1205, Chicago —=— | ee DEPARTMENT OF SIGNALING ay 1810 Wilson Ave., Room 1205, Chicago

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SPECIAL NOTE—If join the Arm Navy before complet- ing your course, all p yment Swill be oatD ed ontil. you return.

AIPA S | LAESE TRESS Fe :

Tt. AP eee meses oS oe aaa Re

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HIGH SCHOOL COURSE IN. TWO YEARS Are you one of the 98% who didn’t finish High School? If so you are badly handicapped. Without this training you are barred from a suc- cessful business career, from the leading professions, from well-paid civil service jobs, from teaching and college entrance, in fact from all worthwhile positions, GET THES You don’t want. TRAINING to be handicapped nor do you have to Re Ow be. Let the Amer- ican School give you the training you missed. Our High School Course covers every subject taught in a resident school. It will broaden your knowledge, make you keen, alert and capable and fit you to earn a higher salary. ‘You can complete the entire course in two years. TAKE 10 LESSONS. AT OUR EXPENSE Test this Course at our expense. Take ten full examinations, thenif you don’t feel satisfied you are not out one cent. Training alone will make you master of your work, able to think and act for yourself, and competent enough to secure and hold the position you want. Whether you lack High School training or specialized instruc- tion NOW is the time to get it. BIG DEMAND FOR SKILLED WORKERS The demand was never greater for skilled workers in every trade and profession. The pay was never higher—the opportunities never greater. Train and get into the game for all it is worth. We guarantee satisfac. § ou do not risk one cent. Check and mail Coupon NOW. _We will promptly send you full details and Free Bulletin. Dept.H-1 RAINING THE KEY TO Tell me how I can fit myself for the position marked X: oa Shop Superintendent +... Lawyer --.. business Manager .... Auditor ....Certified Public Accountant ....Stenographer .-..Bookkeeper ....£ire Insurance Adjuster .-.. Sanitary Engineer «...Automobile Engineer

Address.

THE BOYS’ MAGAZINE—FREE! Send to-day for a free sample copy. Splen- did stories—beautiful illustrations—hand- some covers in colors. Address THE SCOTT F. REDFIELD CO. 2812 Main Street, Smethport, Pa.

How to Make Your Own Lung-Tester | O gymnasium outfit, whether in the athletic club, the office, or the home, is complete without a lung- tester. A reliable lung-tester not only gives information about the capacity of the lungs, but also provides means of competition for those who are proud of their prowess. By practice, too, a boy can increase the capacity of his lungs. Here is a home-made lung-tester suit- able for private use or for a small

The fireman is ‘‘hlowing himself” to find the condition of- his lungs gymnasium without funds to purchase one. The materials needed are: A cylin- der of rust-proof galvanized material about 11 in. high and 7% in. in diameter; a similar cylinder about 10 in. high and 714 in. in diameter; a Y%-in. tube 11 in. long; a 4-in. tube about 10 in. long; a foot of rubber tubing; a rectangular or cylindrical ly-in. rod about 2 ft. long; and a ruler or smoothly planed piece of wood to serve as a gage. Solder the %%-in. tube in a vertical position to the bottom of the larger cylinder, and then attach the \-in. tube to it near the bottom and extend it out through the walls of the tank. Fasten the rubber tubing to the pro- truding end of this tube, and at the end insert the glass tubing to serve as a mouth-piece. The smaller cylindrical tank is to be inverted in the larger, and work up and down. To provide guides to hold it in position, solder ears to both the inside and outside tanks. By means of these attach the -in. cylindrical or rectangular rod, bent as shown in the photograph, to the bottom tank, and adjust the ears on the upper tank so the rod will slip through them freely. Attach the pet-cock to the top of the upper tank in order to allow the air to escape and the device to be set for a second test. In operation, the lower tank is fille< with water to within about an inch of the top. 114 . lungs passes through the rubber tub- The user then blows through Popular Science Monthly. the mouth-piece, and the air from his ing, the 14-in. tube, and the upright - Y-in. pipe above the top of the water, — As the water prevents its escape down. _ ward, the expelled air forces the upper tank upward, and the capacity of the lungs can be measured by the extent of the upward movement. The gage is attached as shown in the photograph. The zero mark is even with the top of the upper tank when it is at its lowest level. The graduations - can be inserted by calculating the capacity of the tank, of course using inside measurements. The glass tub- ing should be sterilized between tests by dipping it in alcohol and rinsing it in water.—FRED TELFORD. A Rivet-Heading Die for Use in the Bench-Vise PECIAL rivet - heads, or even screw-heads, can be easily formed © with the die and holder shown in the illustration. Brass, copper, and soft. iron wire may be easily shaped. The holder A can be made of brass or ma- chine steel. An iron or brass casting may be used. In either case, the piece should be nicely machined for good results. The hole in the center should be counterbored as shown, and the hole C should be drilled and reamed for a smooth finish. <A cut 1-16 in. wide should be made at D-D, dividing the piece A exactly in half. The cut sur- . face should then be filed smooth to re- move all burs. The raised section G is intended to hold the die when it is taken from the vise. The die E can be turned from tool- steel rod to the dimensions shown. No. 8109 0

SA “7 ! ' | ! 4 \ ' ! | ' l

4

NS WX V3.

VISE Jaws The surplus metal may be filed off, leaving a perfect head to the rivet This piece should also be cut in half, the cut in this case being 1-32 in. wide. - All burs must be carefully removed and the surfaces filed smooth. The die should then be hardened so _ that the hammer blows will not mar the surface F. Separate dies can be made for the different shaped heads. Illustrations G, H, J, and K show four types of heads different from the one in the holder, and still other types can be de- signed.—F RANK W. HARTH.

| S \ c ( 1 ‘ .

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ide he urs , re- , 18 ol- vn. valf, ide. and die that the the ions s of the > de- de y Jewelry. { According to our Send No Money! simple, easy pay- ment plan, we willsend you any Diamond for our examination, express prepaid. If satisfied, pay 1/5 of the purchase price and keep it; bal- ance eee into 10 — eaantnadhe ee. SWEET Diamonds are superior in quality, distinctive in beauty, perfect in cut—gorgeous bursts of radiant splendor. Can be exchanged ata yearly increased value of 744%. Ask us about this Profit-Sharing Exchange Plan and for YOUR catalog, No. 479K—IT’S FREE! THE HOUSE OF QUALITY? LWSWEET&CO 2: 4 MAIDEN LANE,NEW YORK AN ASSURED 6% INCOME Your surplus funds will bag 6% if invested in our 6% Time Certificates, issued }: for $100 or more. We have — Fi paid 6% continuously for F} 24 years and have never been a day latein F: : mailing semi-annual interest checks. Allour | :? investments are made in first Mortgages on S improved city property. Write for the Booklet “6% “nd Safety" : The Calvert Mortgage Company : 869 Calvert Building Baltimore, Md. oh CA P. car,i —FR FE ets Sts. a and Lig. Write at on dt Gelee Ofer “an: ‘Spa Age nts wanted demonstrate. Ris tory Open. t shipments, money back. 1919 cars readv. BUSH fasts enccean rss Submit your Song Poems NOW for free examination and advice. We revise poems, compose music of any description, secure a and eme poy on oy ay TR Tae ee acilita- A E PUBL TION Postal oroutright SALE of feongs a... brings under a certiticate copy of our GUARANTEE- Free Booklet which tells R who we ere, explains our methods and contains valu- able “Tstermation and instructions. ty is your opportunity to learn the truth re Song-writing ‘an from a reliable and successful concern Oi STUDIOR, 68 Gaiety Bidg., BY. City repeat ae = ey ee basal. ethan as _ LaSalle Extension University, Dent. aint Chicago pes fore Ome aN 1 he Ge erbetory: Be aor fra bome ens = S&S ee step. gree, ge en- Fourte motor, can be built by any boy. Parts SYPHER MFG. CO. 174 Warren S'. TOLEDO. OHIO A Connection Clip Made from a Safety-Pin OR the electrical operator who wants to make a quick connection to another wire or to a switch, as in tapping on to a telegraph or electric- light line, a light, serviceable testing Ue Vo» ue " A js fin ") HY) i) i e ’ ce aie He ae :) re oy Line operators know the need of a quick and sure connection for telegraph wires clip may be made from a safety-pin. The ends are cut off and bent as shown in the sketch, and a copper wire | is soldered to the back end of the pin.—V. H. Topp. How to Make a Secret Lock for a Drawer SECRET lock that can be made and fitted to a table or desk drawer in a few minutes is herewith illustrated. It consists of a piece of hard wood, A, firmly screwed into the under side of the drawer at the back, and another piece of wood, B, pivoted on one of the side runners or cross- pieces on which the drawer slides. A strong, heavy screw should be used for the pivot, and it should be located well It will be difficult for a stranger to find a secret drawer like this BOYS BUILD THIS CAR This nifty little car driven by gasoline back of the center, so that the weight of ‘the lever keeps its rear end always in contact with the under side of the drawer. A nail, C, prevents the lever from dropping when the drawer is opened. This form of lock does away with the troublesome key, though it is a good plan to cut out a fake key-hole in the front of the drawer to prevent investi- gation of the real method of locking. The drawer automatically locks itself every time it is closed, and is released with the fingers of one hand while the other hand pulls the drawer EARN $35 TO $100 PER WEEK As a Mechanical Draftsman Thousands of Men Wanted You can learn Mechanical Drawing at home in your-spare time through our practical Home Study Course and qualify for Big Pay. We have placed hundreds of our students in good pay- ing positions. Government depart- ments and private ‘concerns are con- tinually calling upon us for our grad- uates. Become a Chief Draftsman and get to the very top in this well-established and rapidly growing profession. The train- ing given by the Columbia School of Drafting will give you just the knowledge -you. need to make good as a Chief Draftsman. No previous training is necessary. You can begin our course now and make rapid progress from the start under the Personal Instruction of the President of the School, Mr. Claflin, by mail. His carefully prepared lessons and personal letters of advice make each step easy and interesting. Draftsmen Now Getting $35 to $100 a Week with big chances for better pay as the demand grows. All big engineering, construction and manufacturing projects must first go through the drafting room before the workmen can commence. All such enterprises depend upon large numbers of draftsmen. Salaries are advancing steadily. Drawing Outfit Free With Our Course As soon as you enroll you will be sent our drawing outfit for your own use throughout the course. This entire outfit will be yours to keep. You are not obliged to return it after completing the course. Not Only a Correspondence School The Columbia School of Drafting is proba- bly the largest residence school in the country, specializing in the training of professional Draftsmen. Our Home Study Courses are an extension of the same instruction as given locally. -Illustrated Catalog FREE Simply fill in the coupon below, return it to us and we will send you free a copy of our illustrated catalog which tells all about our practical Home Study Course and how you may secure our instructions at once on easy terms so as to quickly qualify for one of the big positions open. Send This Coupon Today COLUMBIA SCHOOL OF DRAFTING. Dept. 981, 14th and T Sts., Washington, D. C. Without obligation to me, please send me your II- lustrated Catalog and tell how I may secure your prac- tical training in Drafting and your help in securing a position as Draftsman. CPO O eee eee eee HEHEHE HH ERE E HEHE EHD open.— Morris G. MILLER. 115

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Wanted Draitsmen! Draw t $175.00 to $250.00 Per Month skilled draftsmen. ree Bb to $250.00 pet month. 4 This Complete Set of Drawing mmm (Struments and mreseoeeas! Brewing Table ng paper it class ames ese aere Pay! As You Wish Iitberwhttond shout expense. Yeu can poy. tho-omall ulning evst Send for or My Big New Book FREE =: Sarit triple pote Sa obligation, my 1 ip,”’ and softer that am now ‘on which you Working it and Dra: Tab auaiwice Ginna. smnrton ates. EQUIPMENT Div. 1205, Chicago, Ill. =e oo typo olfer to that 1 am obligated in d foil dl as Be eee Prin Your Own ress $6. rger Job ress ‘outs T'S EXPENSES IN HALF. Bre ros te, me SMALL OUTLAY. Pa carts, circulars, labels, tags, menus . are for for - itself in short time. Will DIRECT FROM FACTORY TO YOU OUR NEW CATALOG WITH 600 OF THE LATEST UP-TO-DATE DESIGNS FREE Cc. K. GROUSE CO. 12 Bruce Ave., North Attleboro, Mass. . GPVASSPNS.AINGS Popular Science Monthly What Can You Do with a Hairpin? Tell us the best way of utilizing a hairpin and Popular Science Monthly will pay you twenty-five dollars. Wy rar do you do with a hairpin? Give it to your wife or sister? that hairpins are invaluable around a Ford car. Throw it away? We happen to know There are, of course, more uses for them, and we want to know in how many practical ways they can be applied in the home and in the shop. Tell us! The POPULAR SCIENCE MONTHLY offers three prizes,—a first prize of $25, a second prize of $15, and a third prize of $10,—to be awarded in accordance with the rules set forth below: Rules Governing the Contest (1) Contestants are not limited to the number of methods of util- izing hairpins which they may describe. But only one method can possibly win the first prize, only one the second, and only one the third. The contest is open to everybody. (2) The method of using hairpins must be clearly shown either in a photograph or in a drawing. If a drawing is sent in, it need - not be made by a skilled drafts- man. It is sufficient that it should be intelligible. While pencil sketches will be considered, con- testants are requested to make their drawings in ink on bristol- board. The views should be sufficient in number to set forth the use of hairpins very clearly. The contestant’s name and address should appear on each sheet of drawings. (3) The drawings or photo- graphs must be accompanied by a description, preferably type- written, in which the method of utilizing a hairpin is clearly given. It must be written on one side -of the paper only, and it should not be more than 500 words in length. The name and address of the contestant should appear in the upper left-hand corner of the first sheet of the written description. (4) The drawings and descrip- tion entered by contestants must be received by the POPULAR SCIENCE MonrTHLY not later than 5 P.M. on June 30, 1919. (5) The judges of the contest will be the editors of the POPULAR SCIENCE MONTHLY. (6) The first prize of $25 will be awarded to the contestant who, in the opinion of the judges, has suggested the simplest and best method of utilizing a hairpin. The second prize of $15 will be paid to the contestant who sub- mits a method next in merit. The third prize of $10 will be paid to thecontestant who sub- mits the method third in merit. (7) The winners of the contest will be announced in the earliest possible issue of POPULAR SCIENCE Montuiy. A description of the methods which won these three prizes offered will duly appear in the pages of the POPULAR SCIENCE MONTHLY, together with the names of the winners. (8) The editors of the PopULAR SCIENCE MONTHLY shall have the right to publish meritorious methods of utilizing hairpins which do not win a prize. The regular space rates will be paid to the contestants who submit manuscripts on the methods thus selected. (9) When a contestant submits more than one method, the de- scription and drawing by which each is set forth must be sent as a separate unit. (10) No manuscripts or draw- ings will be returned to contest- ants. (11) Send drawings and specifi- cations to the Hairpin Contest Edi- tor, POPULAR SCIENCE MONTHLY, 225 West 39th Street, New York City.

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Sea QD core ee ODO DW SF

May, 1919 Side-Tracking Pipe for the Purpose of Economy BRACKET for holding iron pipe, made of a single piece of strap- jron, will carry pipes up to six inches in diameter. There appears to be no

Anybody who has accidentally kicked a six- inch pipe knows the value of a pipe-rack reason why it could not be utilized for larger sizes. The ease with which the pipe is removed is an advantage over old methods.—ERNEST SCHWARTZ. How to Give Longer Life to a Paint-Brush S a precaution in preventing brushes from becoming deformed by resting upon the bottom of the paint-pot when not in use, the follow- ing method is suggested: Bore small holes in the handles of the

Any number of brushes may be kept in the same pot, since none of them rest on the bottom brushes and run a stiff wire through the holes, making sure that the holes are in proper position to compensate for the length of that particular ‘brush. This will always keep the brushes from cramping upon the bottom of the pot.—JAMEs M. KANkE. |

—— :

SS ee Nell! Think What That Means to Us!” | “They’ve made me Superintendent—and doubled my salary! | Now we can have the comforts and pleasures we've dreamed of— } our own home, a maid for you, Nell, and no more worrying | about the cost of living! picked me for promotion three | | | H I’m ready for it.” | Thousands of men now know the joy of happy, prosperous homes because they let the International Correspondence Schools prepare them in spare hours for bigger work and, better pay. | | Why don’t you study some one thing and get ready for a real job, at a salary that will give your wife and children the things you would like | them to have? | You can do it! Pick the position you } want in the work you like best and the I. C. S. will prepare you for it right in i your own home, in your spare time— } you need not lose a day or a dollar from your present occupation. | Yes, you caz do it! More than two mil- } lion have done it in the last twenty-eight years. More than 100,000 are doing it right now. Without cost, without obliga- tion, find out how you can join them. Mark and mail this coupon !

$$ | “The president called me in today and told me. He said he | months ago when he learned I was studying at home with the International Correspondence |} Schools. Now my chance has come—and thanks to the I.C.S, {| CureomaTional tn OUT HER Eee wee cee cee te INTERNATIONAL CORRESPONDENCE SCHOOLS | BOX 7633, SCRANTON, PA.

| Explain, without uvligating me, how I can qualify for the position, or in the subject, before which I mark X. | ELECTRICAL ENGINEER SALESMANSHIP Electric Lighting and Kys. ADVERTISING | Electric Wiring Window Trimmer Telegraph Engineer Show Card Writer Telephone Work Sign Painter MEOCHANIOAL ENGINEER Railroad Trainman Mechanical Draftsman ILLUSTRATING. | Machine Shop Practice Cartooning Tqolmaker BOOKKEEPER Gas Engine Operating Stenographer and Typist CIVIL ENGINEER Cert. Pub. Accountant Surveying and Mapping TRAFFIC MANAGER | MINE FOREMAN or ENGR Railway Accountant STATIONARY ENGINEER Commercial Law Marine Engineer GOOD ENGLISH Ship Draftsman Teacher ARCHITECT Common School Subjects | Contractor and Builder Mathe matics Architectural Drafteman CIVIL SERVICE | Concrete Builder Railway Mail Clerk Structural Engineer AUTOMOBILE OPERATING PLUMBING AND HEATING Auto Repairing Sheet Metal Worker Navigation Spanish Textilo Overseer or Supt. AGRICULTURE French | OHEMIST Poultry Raising §LJItallian Name Present Occupation Street and No A sinc iaoiesiln | City. State ts Me

Canadians may send this coupon to Co d Schvols, Montreal, Canada

I

You can easily learn drafting right at home in spare time. For 28 years the International Cor- respondence Schools have been giving boysjust the training they need for success in Drafting and more than 200 other subjects. Thousands of boys have stepped into good positions through I.C.S. help. Let the I. C.S. help you. Choose the work you like best in the coupon, then mark and mail it. This doesn’t ob!igate ‘ou in the least and it may start you on a successful career. hisis yourchance. Don’t let it slip by. Mark and mail this coupon now. 117 © BOYS! La". Learn everywhere are looking for skilled drafts- splendid chances for advancement. Drafting offers exceptional opportunities to a young man because drafting itself not only commands good pay, butit is the first step toward success in Mechanical or Structural Engineering or Architecture. And z drafting is just the kind of work a boy likes. Ly Employers g ) Vv Ne They are offering good salaries to start with : a — oo ee eee eee eee TEAR OUT HERE © eee eee eee oe aoe INTERNATIONAL CORRESPONDENCE SCHOOLS » Scranton. Pa. Explain fully about your course in the subject marked X : MEOHAN’L DRAFTING D Electrical Engin‘¢ BOOKK’G STRUCT’L DRAFTING Mechanica! Engin’g itenograp'y SHIP DRAFTING otvil Engineering Oivil Service ELECTRIO'L DRAFTIVG f(_|Stationary Engin’g § _)Ry. MallSer. AROHITEO'L DRAFTING I _)Mining Engineer’g Ff JAUTOMOB'S SH’T METAL DRAFTING OL | AROHITEOTURE OHEMIST'Y

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PATENTS JF 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 invéntion 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 patentability without any expense to the client. Our Hand-Book on Patents is sent free on request. This explains ,our methods, terms, etc., in regard to Patents, Trade Marks, Foreign Patents, etc. If you are a reader of the SCIENTIFIC AMERICAN = are probably aware of the 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- ent legislation as well as the most recent rulings of the Patent Office and the courts are considered in its columns. MUNN & CO. SOLICITORS OF PATENTS 683 Woolworth Bldg. NEW YORK and 624 F Street, WASHINGTON, D. C.

Maximum Profit ~ Minimum Risk The question as to which securities among the country’s foremost industrials, railroads, cop- } pers and oils, offer the maximum profit, combined i With stability of principal and marketability, is currently covered in our fortnightly publication

Investment Opportunities An inquiry for 3-PS, will bring this publica- } tion, with booklet, explaining he Gwenty Payment Plan S ALTE PRY'e 6 40 Exchange Place, New York

It's Easy With Our Help - Build Your Own PHONOGRAPH Write Today for Our Free . Blue Print Offer Agents wanted for our ready built phonographs Choraleon Phonograph Co. 605 Monger Bidg., Elkhart, Ind.

Raise Belgian Hares for us. Wonderful profits easily made athome. We furnish stock and pay you $6 a pair and express charges and buy all you raise. Also cavies and squabs.

Beautifal illustrated catalog and contract 10c UNITED FOOD & FUR ASSOCIATION 329 West 48th St. Desk 4 New York

The Wash-Boiler Becomes an Automobile Popular Science Me ; When painted and striped it looks like the real thing NEAT, light, and very durable body for a toy automobile can be made quickly and inexpensively from an old wash-boiler; and at the same time, if the work is neatly done, the body prop- By R. J. Stevens The wire rim is not cut at B, but the sheet. metal is unfolded from the rim, from A to B, and the hood is then cut off. In making the cut from EF to B allowance should be made for a ig] VI Pe a2 def 2 a > 5) FO, es ANU EO Bye. a \- OU Cia

For all the world like <‘real automobile, the “flying start” is made realistic: by young America’s imagination erly painted, and the hood striped to represent the radiator, it will have the appearance of the expensive store article. There are no details given here as to the steering and running gear, because every boy mechanic is thoroughly familiar with the many designs used. The first process, in cutting up the boiler, is to saw through the rim A on both sides of the boiler, about 11% in. from the line denoting the cut for the hood—the object being to have as Cc fA 12° B @uii| UH TA i | | i A il

A «—_ 15° —|9

How the body is applied to the frame, and the method of cutting the boiler much of the wire rim as possible for re- inforcing the seat from E to B, without robbing the hood. 118

enough material to fold over the rein- forcing wire. Note that the chassis is so con- structed that the width of the hood measures 2 in. more in the back than in the front. The last sketch shows the general appearance of the body. The boxing up of the inside of this will depend entirely upon the type of steering gear used. Transferring Oil on Vessels by the Siphon Process HILE employed to oil counter- shafts in a large machine-shop, I found the task of emptying the oil drip-pans and saving the oil a job requiring some time and skill. I secured a 5-ft. length of in. tubing and bent one end in the form of a hook, with a bend of about Y.in. radius—this end being the top of the siphon, or the part to hook over the oil drip-pans to remove the oil. To start the siphon effect of the oil-tube, I used a deep vessel to catch and save the oil, putting about 3 in. of oil into it. By dipping the bottom of the siphon into the oil in the salvaging vessel, hooking the tube into the oil drip-pan, and lowering the vessel, the pull of the oil in the bottom of the tube started the siphon effect and the oil drip-pan was soon emptied. Of course, the larger the tube, the quicker the process.— WILLIAM McCARTHY.

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» COn- - hood ¢ than eneral boxing lepend ig gear sssels $8 yunter- e-shop, ig the | a job Yin. e form about he top » hook remove of the ssel to r about ing the the oil ooking in, and of the started rip-pan se, the er the May, 1919 To Prevent a Countersink from Wabbling COUNTERSINK, especially the kind known as the rose, has a tendency to wabble when a compara- tively large hole is to be worked in sheet-metal. This causes the hole to pecome uneven and thereby unsightly, and prevents the head of the screw from seating properly. Asimple and infallible reme- dy for this trouble consists in clamping a piece of hard wood to the back of the metal to be worked. Ifthe countersink play is easily hole to be overcome when three-way countersunk is screws hold it in position already large to start with, the center should be marked on the wood with a center punch. It is still better to drill a small hole through the place where the center will come in the wood, as this makes it easier for the countersink to bite. This causes the point of the coun- tersink to be firmly engaged; and, since all play is thus eliminated, it will be found that a perfectly true, clean hole in the metal will be the result.— HENRY SIMON. Submerged Scissors Cut Glass Easily FTEN an odd-shaped piece of glass will get broken, as, for instance, in an electrical instrument; and it is very difficult to cut an odd- shaped piece of glass without special guides. Ordinary window-glass may be cut to almost any desired shape by holding it beneath the surface of a pan of water and cutting with house shears. Submerged scissors will do the work of a glass-cutter if care is used Of course, it cannot be cut accurately straight across the piece, but it may be “chewed out’? very much the same as can be done with a piece of card- hoard.—V. H. Topp. TheseBooksWillPut ouinaBefter Job . Special price Civil pie Nine volumes, 3900 pages Gingrams, Erepated or Givitor 1 pany = E er A Chit D: Drafterian., price,$45. price $89.80, ‘tahoe and Telegra Ih: Four seiamen 1728 B A ustrations, D ty ae, ene 6 Bigincer, De Wire Chief, Eri er ine | 0 le price, $20.00, price,$1 - En . ring nee Seven volumes 1) es and 2500 illastrations, onary, Marine oy phew Locomotive or Fireman. Regular eae wa “ty low and mail the coupon for one of these pay-raising sets of books. They are writ- ten by some of the greatest ex- perts in each line and tell everything you Pipa know to make So an expert and put youina tter job. Plain everyday English, pictures, diagrams, plans, etc., make diffi- c ult things simple as A-B-C. Thousands of men have used these booksand are making more money. Hundreds are doing it every day. You can do it too. ick out the set that suits your own work best and send for it for a week’s free trial. Your Choice a 50 Cents a Week Carpe Automeiiie Garage F A obi. Mechanic or Chauffeur. Inval- uable to car owners. Drice,$25.00. Special price 411.8, MachineShopPractice oe x ee, 2 2300 pbaces and Machine Bt Shop s —_ = or Foreman, orn Maker, Tool Designer or $30.00. “Special price, #.50. Sanitary, Heating and Ventilating Engin’ring Four volumes, 1454 pages and me ¥ _R. a Ray illustrations, Eee: “i ; Heating and Ven Serer Biombe Master price,s20. = ie peers aa volumes, more than one teens lus: ns, pares fi tectaral or eae of Danio Special price, Only Sisrne 80, Law and Practice Swit, Read: Course in 25 pam ). irteen oneal pages trations. Prepares for all B Examinations. A wonderful aid to business men. price,$72.00. Special price, Practical 1987 illustrations, for fied ib Accountant, Auditor, Office Manager, ——, redit Man or r, Book price,$50.00. The ee is on’t Sen oney 3yo ne Just fill out and mail it. We will ship the books at once by express , collect right to your own home and you can have them a whole week to use as you please. Give them every test you can think of—show them to your friends and get their opinion. Then ship them back at our expense if you don’t want to keep them. If you do want the books to help put you in a better job, just send us $2.00. You can send the balance of the special reduced price the same way—$2.00 a month. (50 cents a week.) Send the coupon now! Before you turn this page. AMERICAN TECHNICAL SOCIETY Dept. X-1205, Chicago, Ill. Special Offer! e To those who mail this coupon romptly we will give absolutely at oe a year’s membership in the American Technical Society with every set of books. This will enable you to consult our f engineers and experts on any prob- lem connected with your work. It usually sells for $12.00 but it will be é grea free while a limited amount a of mem) ips remain open. ee American Technical Society, Dept. X-1205, Chicago, Il. Please send me set of. for 7 days’ ay shipping Cy collect. ; will ——- the books > will sn @2 within 7 days and §2 each If I decide not to y cxpreia at yourexpense, Title not thoroughly and, if satisfied, month until I have paid the special price keep the books, I will return them rrr rrirry to pass to me until the set is fully paid fo Name Address Reference,

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PATENT COPYRIGHTS 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. Highest References Our Illustrated 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. Prompt Service TRADE-MARKS Reasonable Terms | VICTOR J. EVANS & CO., Patent Attorneys ! i New York Offices z Philadelphia Offices Pittsburgh Offices I , 1001 Woolworth Bidg. 135 S. Broad Street 514 Empire Bldg. i y Main Offices: 760 9th Street, N. W.. WASHINGTON, D.C. |! 1 GENTLEMEN: Please send me FREE OF CHARGE your Book as described above. £ , es 5 ows sacs pws ce ws secs (0 TUS gediaes fa ihan Set ony et a ne 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 best way of obtaining patent protectic Our practical experience covers a period of twenty years. Our Handbook on Patents HOWtoOBTAINaPATENT SENT FREE is a storeb sof valuableinformationand /£ advice toinventors. Allcommunications strictly confidential. Write as TODAY. Ak CUP eiveavr ere ae ete ptr ease rvates PATENTS 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 39-T Loan aud Trust Building, Washing'on, D.C. DERTECECRUAA AMET ERE CO LP EGET eae cece ra rea asire etvneeeteaacetareeereeeeo ait eaetaeeeearee he OREO LUO ELIEETRRGLE LT RGEAREE EET OURS ROU UCEOSCUCEE USE ROCR EC OIEOE ETERS 208 3! Se eee TENTS 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., 1336 Schofield Bidg., Washington, D. & Cleveland, Ohio. —_ — Popular Science Monthh One Way to Improve the Lawn-Rake + ie = best type of lawn-rake has this drawback: the tooth-holding bar always becomes loose, and in this con. dition is decidedly unsatisfactory, The method here illustrated will al- ways keep the tooth-bar tight and do away with this objectionable feature. Gf With this idea applied to the lawn-rake all annoyances will be a thing of the past Cut a soft pine wedge and fit it between the arms that hold the tooth- bar. Force in the wedge, but not hard enough to break. the arms. Four small nails driven in beneath: the arms will keep the wedge in place. Bore a small hole through the tooth- bar, run a long screw through the wedge and into the handle, and you will have a rake always ready for use.—JAMES M. KANE. Cutting or Breaking Gage- Glass with Electricity S shown in the illustration, a high- resistance wireis arranged between binding-posts on a suitable base; line connections are made at terminals T, and T,. Tightening or loosening the middle binding-post wili allow adjustment for accommodating dif- ferent sizes of tubes. - Fhen the re- COMPETENT PATENT SERVICE By a Former Examining Official of the U.S. Patent Office NORMAN T. WHITAKER Lawyer and Engineer 280 Whitaker Bldg., Wash., D.C. New York Office, 87 Nassau Street, New York INQUIRIES INVITED Terms Reasonable PATENTS Write for free booklet Highest References Send model or drawing for preliminary examination and report as to patentability Best Results ALL BUSINESS GIVEN PROMPT AND PROPER ATTENTION WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D.C. Supply mains Middle Coilof high binding: High res-wire ohare Tubing res.wire ; post 7 “The wire must be drawn tightly about the gage-glass or a short circuit will result sistance wire is looped around the glass at the point to be cut and connected: to the post T,. After the current has been turned on for a while, and the wire has become red-hot, remove the glass tube and plunge it into water. This will produce a clean break. The wire must be drawn tightly around the tube, and must be slightly separated at what would ordinarily be the meeting point of the loop. Otherwise a short circuit would result, and the wire loop would not heat up.—PETER J. M. CLUTE.

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ll al- d do ture, ast fit it ooth- ; not arms. neath - lace. ooth- 1 the 1 you y for ige= high- tr it the -esult e glass nected ont has nd the ve the water. tightly lightly linarily » loop. result, t heat May, 1919 One Way to Make Egg- Collecting Easy “fOLLECTING eggs at the back- yard poultry-house is much easier than ordering them by telephone from the grocery,” says one housewife, “‘if husband has equipped the poultry- house with exterior nests. ; The idea is very simple and is easily applied. Several rectangular nest holes are cut in the rear house wall about three feet from the floor. In just the same position with these on the outside of the house is attached a long nesting compartment 18 in. wide, 18 in. high in the back, and 15 in. high in front. Partitions are not necessary. The compartment has a tight, sloping, The “‘self-service” hen egg-house gives the housewife an excellent foresight as to egg prospects for the future hinged cover to shed rain or water. The number of entrances should be one to about every two feet. In obtaining eggs, the housewife simply steps to the back of the house and lifts the cover. At one glance she sees her visible egg supply and gathers an excellent idea of her “prospects.”” This nesting compart- ment should be made absolutely weather-proof; otherwise draughts will destroy its efficiency.—J. T. BARTLETT. Cork wud Glass of Water Trick O amuse a company, fill a glass nearly full of water, and drop into it a cork. The cork will naturally float on top. Then essay a bet that you can place the glass of water in such a position that no one can remove the cork without spilling every drop of water. ; After. everyone has given up the problem, take a piece of heavy paper or stiff cardboard and cover the glass with it by laying it over the top. Then invert the glass. No water will fall out, owing to the air-pressure. Now set the glass on a plate, still inverted, and gradually work out the piece of cardboard. The cork will immediately float to the top of the water-level, thus being mm a position where removal is im- possible without spilling every drop of PATENTS 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 pnts ee ee eee eee ee patentable nature. RANDOLPH @& CQ. © ommmtteececcccccccccccccccccsesseses: 130 F St., N. W., Washington, D. C. OT ee RUAN as sss eects IF YOU HAVE AN INVENTION AND DESIRE TO LEARN HOW TO There are over 2,000 ph trations of Diamond Rings, Diamond ¢ La Vallieres, Diamond Ear Screws, Diamond Scarf Pins, Diamond Studs, Watches, Wrist Watches; ¢@ also our wonderful showy assem= Jiasss bled Solitaire Diamond Clusters. photetrraphic illus- 4 1 Loftis Perfection Diamond Rings Each Diamond is specially selected by our diamond experts and is skil- fully mounted in our famous Lof- tis ‘*Perfection’’ 14-karat solid gold 6-prong ring, possessing every line of delicate grace and beauty. $10 Down, $5 a Month, buys a $50 Ring. ‘eo $20 Down, $10a Month, buys a $100 Ring, $25 Down,$12.50a Month, .buys a $125 Ring. Every Article in Our Large oy Catalog is specially selected and priced unusually : = low. Whatever you select will regain * be sent prepaid by us. You see and examine the article right in your own hands. If sat- isfied, pay one-fifth of purchase price and keep it; balance divided into eight equal amounts, payablemonthly. Stand- ard world-renowned watches on it terms as low as $2.50 a month. Send for Catalog. LIBERTY BONDS ACCEPTED. [OF TI The National Credit Jewelers eM TS th BROS & CO. iss8 STORES IN LEADING CITIES CAN YOU think of a simple, practical idea that will fill one of the many re- quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed RIGHT Now. Your brains can help, Send to- day for our great new book—“‘Inven- tions and Trade Marks, Their Protection and Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many © things that are wanted, too. 4 postal will do— it is free. We help our clients, PATENTS the dollars out of thelr ADVERTISED one es pele For SALE FREE Advice free. In INVENTION And ——- MANUFACTURING SUPPLEMENT. AMERICAN Published for the man with an idea. INDUSTRIES, INC, 201 Patent Dept., b+ omg Gao pene WASHINGTON, D.C, il scription 50c. water.—CLARENCE T, HUBBARD. PATENTS AND —\TRADE MARKS _ 274 OURAY BLDG, WASHINGTON, D.C, DO NOT LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone 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 cf their inventions. Terms reasonable. The form “Evid of tion,’’ sample, instructions relating to obtaining of ; patent and fee schedule sent upon request. Ask for them,—a postcard will do. PATENTS LACEY & LACEY i ttorneys-at-Law — Pateat Practice Exclusively Solicitors of | U.S. and Foreign Patents Trade-Marks, Copyrights. 645 F Street, N.W., Washington, D.C. Write Us for Our Free Inventors’ Book PATENT-SENSE em ESTABLISHED 1869 cme ELECTRICITY MADE SIMPLE A book devoid ‘of technicalities. Simple, plain and understandable. .$1.00 Postpaid. POPULAR SCIENCE MONTHLY 225 West 39th Street 33 New York : 121 To the Man With an Idea I offer a comprehensive, experi- enced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and descrip- tion, for advice as to cost, search through prior United States pat- ents, etc. Preliminary advice glad- ly furnished without charge. My experience and familiarity with various arts, froquently enable me to accurately cxivise clients as to probable patentability before they go to any expense, Bookict of valuable infevmation and form a for properly disclosing your idea, free on request. Writc today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C. 2276-D Woolworth Building, New York City BUCHSTEIN’S FIBRE LIMB is soothing to your stump,— strong, cool, neat, light. >», Easy payments. ™~ 9 Braces J for all Guaranteed 5 Years deform- Send ior Catalog Today ities. P. BUCHSTEIN CO., 113 6th St. S., MINNEAPOLIS, MINN, aT:

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Every year Riverside Tire Sales have shown a remarkable growth. It is our aim to give autoists the best tire value obtainable. Increased sales and manufacturing facilities have made possible a big reduction in prices—the lowest price in months. This new k tells all about Riverside Tires—the peices prove that Riversides give you “Most for the Money.” TRADE MARK Auto Owners and Garage Men Get This Big New FREE Book Over 2000 selections are offered in this book. Supplies that will improve all cars. There are ires with a 5000-Mile Guarantee. Tools i! ‘ : of ail kinds to make repairing easy—gas savers for getting more miles out of each gal- jon—tourists’ supplies needed on a trip—shock absorbers for smooth riding—painting outfits to make your car better looking and worth more —supplies for giving your engine more power. In fact, there is probably not a single thing you will need but what you will find it id this FREE BOOK—and the price will be reasonable. RIVERSIDE 3°00 ee TIRES Many brand new supplies are shown in this book—necessities you may never have seen or heard of. Prices have been lowered on many important articles: 25 pages out of the 100 in this book areexclusively for Ford owners. Every car owner and garage man should always keep this book handy, as it will prove a valuable guide to low prices. Write Now for Your FREE Copy FORT WORTH COMFORTABLE—COMPACT For convenience,strength andcom- fort—on camping trips, for porches or extra furnitufe 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 1h with steel plates riveted on. i Write for catalog showing cots, chairs, tents, etc. Gold Medal Camp Furniture Mfg. Co. Dept.7 Racine, Wis “Slickest. Trick You Ever Saw.” One minute it’s a roadster—with a sturdy, j| roomy wagon-bed, big enough to haul ice and wood, and tools, ‘‘an’ everything.” = And the next minute it’s the niftiest speedster you ever sSaw—a road coaster, built for coasting, with a stream- line body, long and lean like a greyhound. The Auto-Wheel Convertible Roadster, like its older brother, the Auto-Wheel Coaster, is built very much like an automobile, ‘with oval spokes, roller bearings, and steel axles. The tires, of course, are of steel to give long, hard service. The Convertible arrangement of the Auto-Wheel Road- * ster and the patented Lock-and-Release feature on the bed of the Auto-Wheel Coaster give these racers real class. They are different all through—better all around. to boy wh FREE—Felt Pennant 0¢ ‘coaster wason deniers: mention: ing which one handles the Auto- Wheel, Our color catalog goes with the Pennant. Free Cap to each member of Auto-Wheel Coaster Club. A-special cap goes to the Captain. Write today for details and have the time of your life, BUFFALO SLED CO., ~ 157 Schenck Street, In Canada: N. Tonawanda, Preston, Ont. ° —SS= as ARMATURE AND MAGNET WINDING ~ bY Horstmann & Tousley A necessary book for Electricians. Full facts and aWeek pays] ‘ortne Black Beauty FF‘ BOYS! Don’t buy an ordi- nary bicycle. Get a Black Beauty — FI actory - direct; wholesale price. Built for you ever did see. A thriller! 18 Exclusive Features. See the wheel itself. Any one of 20 styles shipped ab- solutely at our risk. No Ph | urn. We pay freight. At | Months to pay if you decide Vi to keep it—small amount on acceptance, then $1 a week. Guar. 5 years. Greatest offer ever made. waveRFORD CYCLE CO. (Est. 23 years) Dept. S62 Philadelphia Beautiful New Catalog in colors diagrams, $1.50 postpaid. Popular Science Monthly, 225 W. 39th St., New York SS ! lie nm “Saved $1002° See97 On My Diamond” Th di d t to Ya er ee eS (Ser Vg ing of $100).—Name on request. sree jy Rig 4 8/4 cen r old, Soted over 000,000.00, is money on welry. bargains in unpaid loan diamonds. Why Pay Full Prices Prove for yourself that name for wonderful lists free. Every — accurately described in detail. Radically diff rom Catal See these prices before you buy. oe Send for Latest List , Diamond Loans Fe op on ae monds far under market prices: 4 aa, f nation. Amazing b ins proved by cus- tomers’ letters. Write today. Jos. DeRoy & Sons, 4750 DeRoy Bldg. ie Nesbnas San Union An Inexpensive Method of Photographing Drawings T is often desired to kee Popular Science Monthly m ; P a record drawings that must be sent i. temporarily. This can be done in- expensively with a _ small pocket camera, 314x444 in. While the Photo- rimst rues Oe The sketch or drawing is first tacked upon the board and then photographed prints are small, they can be easily read with the aid of a magnifying- glass. There are two ways of taking pic- tures of this kind, one being to set the drawing up with the light shining upon it and give it a ten-second exposure. The other and more preferable way is to secure the drawing to a window with stickers, block out all the other light so Placing the drawing upon a window and then blotting out all other light is another way to photograph drawings — that all of the light will come through the drawing. Then focus the camera upon the drawing, give it an exposure of two seconds, and a satisfactory negative will result. The top print was obtained by the former method, the lower one by the latter. Blue-prints may also be photo- graphed in this manner if the second system is used and they are given an exposure of about fifteen seconds. Blue-prints, of course, will come up with the lines white on a black back- ground.—GEORGE M. PETERSEN.

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rough ymera osure ctory print thod, yhoto- econd en an -onds. ne up back- May, 1919 to Build an Atiractive How Pergola unds around country houses |e Eccally some hillside or slight incline where the landscape will be im- proved by building a small summer- house or pergola. This type of building is very easy to make and only a few tools are needed. It adds something to the artistic appearance of attractive grounds Any boy can erect and paint such a structure with the following materials: 4 pieces 5-by-5 in. lumber, 2 pieces 4- by-5 in. lumber, 4 pieces 314-by-4 in. lumber, 4 pieces 1-by-4 in. lumber, 5 pieces 114-by-12 in. lumber, 10 pieces 1-by-4 in. lumber, 1 piece 2-by-2 in. lumber, 8 ft. lumber for posts, 41% ft. lumber for caps, 2 ft. by 4 in. lumber for side-rails, 4 ft. by 4 in. lumber for side-slats, 614 ft. lumber for pergola beams, 41% ft. lumber for top slats, 4144 ft. lumber for front slat-mold on roof, 2 bunches cedar shingles for the roof. The drawings show clearly the nature of the different members and the exact method of putting them together by Though simply constructed, the finished work has very pleasing lines mortise, ete. The curved beams would be best made of one piece, and for this a plank of good width will be required. These can be cut out at a sawmill, but the amateur craftsman should finda deal of pleasure in cutting them for himself. A pattern (ful! size) is first made, and the rest of the pieces are cut from it. The sizes shown in the drawing de- note the common size of timbers usu- ally found in stock in a lumber-yard. Variations eculd be made in the struc- ture without injury to the general design.— WILLIAM E. FRUDDEN. Thousands of Electrical experts are needed now. Come to the great shops of Coyne and let us train you quickly by our sure practical way backed by 20 years of success. LEARN DRAFTING Earn $125 to $320 a Month The country needs hundreds of skilled Draftsmen Come to Coyne where experts train | in all lines at big salaries. you on the actual apparatus. . y ou work Coyne is the only school in the country that gives pi everything from the simple bell to you the advantages of big shops full of Construction g s | = z im : and machinery. This makes our drafting courses the mighty Generators, Electrical Loco- practical, just like the job you’ll have when you grad- motives and Power Plants. Everything | uate. You can’t get this in any other school. to make youa Master Electrician. Look WE TEACH ELECTRICITY, DRAFTING at the picture taken from life in our MOTION PICTURE OPERATING ‘AND PLUMBING p We teach all these professions in such a thorough, shops. practical way — when be finish you can stepright s into a position of responsibility and big pay. Become an Expert In 3% Months Fill out the coupon now and send it for our big ¢ free book of information. It tells what others are No need of taking I to 4 years to be- doing and have done, what you can do. come an expert. We have proved this Be sure and check the trade that interests you. He it now. in thousands of cases. We aretheonly school teach- 7 @= 3 3 we we a oe ee eee ing by the original Coyne methods, which means no i ee ee Re - : se - ept. 35, 39- . inols St. books, no classes—all practical training. t CHICAGO, ILL. Earn Your Way. Our employment department will 4 help every ambitious man to earn a part or all his expenses—without charge. E Bennett W. Cooke, Director. COYNE TRADE AND ENGINEERING SCHOOLS I’m interested in: Motion Picture Operating Dept. 35, 39-51 E. Illinois Street i INDIE) «.¢ 6:0:0 ne 46: os acicidias cvrcetede ee CHICAGO, ILL. ty cori smntarensianinaal Please send me that big free book. OElectricity (CDrafting € Plumbing Find Out Right Now How You Can Get This Car—Mail Coupon 115-inch Wheelbase And the Agency In 36H. P. 32x 32 Tires ceria Electric Lights and Starter . Your Territory & The World’s Greatest Motor Car Value Write NOW for full specifications of New 1919 Model BIRCH SUPER-FOUR RCH MOTOR CARS, Dept. 518 A big opportunity is open to ambitious men who are willing to rT » Dept. 518 Seis eeeeioes and then get out and hustle. We pay big commissions 1 E. Madison St., Chicago for selling Birch Cars, Ww sa = e require all our Previous Experience Not Necessary agents to take a A u brief but thorough course of training in Automobile Driving and Selling. We have trained hundreds of others for success in this way. 80% of Birch Carsare in use by farmersandinsmall # Name towns and get the hardest kind of service. Mud, rocks, sand, hills and rough going have no terrors for these sturdy cars. Send Coupon for i 4 F Book BIRCH MOTOR CARS °° cpuicasoene of Chicago Association of Commerce. caiaceeaeiiah Please send free book and fuii partic- lars asto Birch Super-Fourandagency. 123 Aaa ee Se x x ee ee

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ofa few cents a day. r’s You may have your choice of more than 2,000 instrum ’s trial i your own home, Play it as if it were your own. Then, Poe Sete ey Ae at our expense, Trial does not cost you apenny. Don’t miss this big offer. Convenient Monthly Payments os you decide to buy ou may pay the low manufacturer’s price at the rate . nearly two centuries. Every known musical instrument sold to you at direct- acture’ rice. We’ve supplied U. S. 4 Gov’t with trumpets tor 65 years. Send the Coupon Just put your nameand address on the coupon Please state what instrument you are interested 7 in. There is no obligation. We will send you the big y 160-page book free and prepaid. Send coupon now! y; about your special offer direct from tho re. The Rudolph Wurlitzer Co. Dept. 1205 East Fourth Street, Cincinnati, Ohio. g° Address....ss...ssssesscsesssnssseessseseessesseesssesecee South Wabash Avenue, Chicago, IIl. iFree Trial a Week en, if you wish, you may send it back ‘urlitzer’’ has stood for the highest quality for , del RAR Oe ee LE @ The Rudolph Wurlitzer Co OB Gh Seren Cinseaati, Obio S. Wabash Avenue, Chicago, Lil. Ge ntlemen:—Please send me your 160- page catalog, absolutely free. Also tell manufacture: ¢ Name. ¢ REE ane OTe OO ee (Name of instrument here) Seek This Man-Made Amber t pein as the word Sterling on silverware designates the best quality, the word Redmanol in- sures perfection in pipe mouth- pieces, cigar and cigarette holders. Any mouthpiece that displays the word Redmanol is the successful result of scientific application to create a man-made amber. In its individuality of design, and in its perfect workmanship you will recognize the work of artists. Redmanol mouthpieces are hand- cut, and never lose their amber color or their sparkle. Redmanol pipes and holders are for sale by leading dealers. If your local dealer is unable to supply you send us his name and we will see that you are supplied. Redmanol Chemical Products Co. Dept. 26 Chicago, Ill, REDMANOL The largest selling uality penct: in the world © 17 black degrees and. 3 copying it IN every profession, business and trade the Famous VENUS Pencils are minimiz- ing labor and adding to the speed, facility and accuracy of the work rformed by them, cause each Pencil embodies Per- fection. SPECIAL 14c OFFER Send 14 cents for three trial samples mentioning degree3. After you find how perfect VENUS Pencils are buy them of any dealer. American Lead Pencil Company 246 Fifth Avenue, New York and Clapton, London, Eng. MAGAZINE - Publishes cash r art assignments, lessons and articles on Care tooning, Designing, Illustrating, Lettering, and “6 Crit- icises amateurs’ work. Full of in- teresting and _ helpful information for artists and art students. Satisfactory or Y money refunded. 10 cents a copy, $1 a year. Send $1 NOW, stamps or bill. ( STUDENTS ART MAGAZINE, Dept. 448, Kalamazoo. Mich. -N=i-me 15> CLASS OR SOCIETY—CATALOG FREE ° Either pin illustrated made with any 8 letters and 2 fig- y= ures, Enameled Red-White- Z v* Blue, Silver plate 2Cc ea., SB! $2.00 doz. Sterling silver, 35c ea., $3.50 doz. BASTIAN BROS. CO. 770 Bastian Bldg., Rochester, N. Y DEAFNESS IS MISERY I know because I-was Deaf and had Head Noises for over 30 years. My invisible Antiseptic Ear Drums restored my hearing and stepped 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. Easy to put in, easy to take out. Are “Unseen Comforts.”” 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 — 1% Popular Science Monthly The Right Way to Take Up Slack in Tiller-Ropes ar motor-boats that are steered by a wheel placed forward of amidships can make good use of the accompanying simple idea to take up ae Damp weather nor old rope can not affect the boat’s steering control if you take up the slack with spiral springs automatically the slack in the tiller- ropes between the wheel and the rudder. Remove a short section of the rope on each side of the wheel, and into these spaces insert two spiral springs similar to common door-springs. Arrange the springs so there will always be a slight tension on them when the steering- gear is not in use. Then, when the boat is under way and there is a strain upon the tiller-ropes, the springs will take up all the stretching that would eventually occur.—L. B. ROBBINS. Why Does a Chicken Cross the Road? ICKING up old pieces of pipe in odd corners about the farm, an up-to-date farmer turned them over to the village blacksmith and told him to make the framework for an iron gate. GUY-WIRE Because it is easier for her to walk through a specially made gateway than to fly over the barn-yard fence The wire fretwork was woven by the farmer in his spare time. The gate is unique in that it possesses a panel (A) left uncovered to permit the poultry free access to and from the barn-yard.—J. M. KANE.

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rt ‘Ss iller- the rope these milar e the light ring- 1 the train 3 will vould DSS pe in n, an rer to im to gate, — SS Ue y the sesses it the n the - May, 1919 Keep Your Scale in Your Pocket with a Brass Clip O make a practical clip that will attach a carpenter’s steel scale to his pocket, all that is needed is a piece of sheet brass cut wide enough to allow it to lap over the back of the scale about Yin. After this is done cut away the surplus stock on both sides of the piece of brass, which will take the shape of the letter T. Place the clip on a vise and clamp, the Mit — 1% —| la TTT | | yy" PLA Se a ie a ee SPRING nee SIDE Le | Ree 5 t BOTTOM is No excuse now for losing your pocket - rule if it has this easily made clip clip and the scale tightly together, so that the edges of the clip may be turned over with a hammer to hold it on the scale. Remove and file, finally polishing with an emery cloth, then bending the spring into shape.—H. KEPPLER. Juggling a Wine-Glass on Top of a Card HE performer takes up a playing card, displaying both sides, and also exhibits a small wine-glass. Plac- ing the card on the edge of the glass, it tilts the card, and the glass appears to be balanced on the card. To accomplish this feat, two cards This trick, which appears almost impossible, is simply a matter of pasting two cards together are pasted together. The back card, to be exact, is only half pasted, so that running lengthwise there is a “flap.” When the flap is extended it will do the trick as shown in the illustration.—CLARENCE T. HUBBARD. Big Salaries for “Specialized Brains” in Business Here is convincing proof that specialized business knowledge will put you into a better position—raise your salary. Read below how ambitious men were quickly promoted after taking the LaSalle train- ing which made their services worth more. __ The same training which enabled them to advance is offered you. Do as they did—train! LaSalle experts can give you the knowledge that commands high pay. At least write for information. iso, Expert Accountants Earn $3,000 to $10,000 a Year Business today cannot be run “by guess.” Officers and directors must have accurate information on the conditions of every department. They must know where profits are being made; where losses can be stopped and expansion encouraged. The Higher Accountant shows them all this. He is the business analyst, the depart- mental organizer. Specialized ability.todo these things naturally brings a big income, Train By Mail You can get this training in your own home. No need to leave your present posi- tion until you are ready for the better one. The LaSalle extension method brings the instruction by mail. Use only your spare time. The cost of the course is small and you can pay on our easy terms—a little each month if you wish. end the coupon today and get the facts. “Passed Ohio C, P. A. ex- “Since taking my LaSalle amination with high cre- course my earning capacity dit,” R.F. B. has increased 400 per cent.” Am business managerof H,S. W. , a corporation with assets of ‘Your course benefited me so much it netted me over $4,000,000." W.M.C. “Am now one of theoffi- 6500 per_cent profit in a cials of the company with year.” F. H. increased salary because I Salary increased 288 per am able to present state- cent withina year.” L.C. R. ments toourdirectors, show- , Returns in 6 months 10 ing the true conditions of timesthecostof thecourse.” affairs at anytime.’ C.A.E, F.J.F. A Become An Expert This training re you a thoro knowledge of every principle of accounting and its practical application. You take up the very problems that are met daily in actual business. You are given the combined experience of many ac- counting authorities. When you master one point, you go ahead to the next. You cover in months what it might take years for you to obtain from experience in the office. Instruction by Practical Men The LaSalle method will train you under the direct supervision of William B.*Castenholz, A. M., C. P. A., Former Comptroller and In- structor, University of Illinois, assisted by astaff of Certified Public Accountants including mem- bers of the American Institute of Accountants. Analysisand Organization, and the Principles of Accounting, Auditing, Commercial Law and Scientific Management all made clear. They will prepare you for the Civil Service and C. P. A. examinations, to hold an executive position or to enter business as an Expert Consulting Accountant.. Enrollment also gives you the free use of our Consulting Service which brings advice on any important business problem whenever you need it. Send the Coupon Your request will bring fullinformation about this home training in Higher Accounting and our valuable book, *“Ten Years’ Promotion In One;’”’ also our book, “Proof,”’ giving testimonials of hundreds of men who have advanced thra LaSalle training. No cost to you; no obligation, At isast investigate. Mail the coupon now. LaSALLE EXTENSION UNIVERSITY “The World’s Greatest Extension Unis ity’ i Without cost or obligation on my part, please send me particulars regarding ining in Higher Accounting and your Consulting Service. Also your books, “Ten Years’ Promotion In One” and “*Proof.”’ Dept. 583-HA your Extension Course of Name. » Mlinois eeeeceeee The Ar the tion Triangle with a Brain—will multiply. divide, figure percentage and proportion, solve all problems in trigonometry and geometry, draw symmetrical figures, plot arcs, etc. Superior to any slide rule. Simple to operate. Also includes A TRANSPARENT TRIANGLE, PROTRACTOR and THREE RULES. Used at Columbia University, West Point, U. S. Aeronautic Schools, Ete. Only 85c postpaid. Order today before you forget. vept. U, L. J. LEISHMAN CO. Ogden, Utah Mathematics Made Easy °90to*250aMonth § FreeBool TellsHow Write today for this big, new Free Book on SIGNAL ENGINEERING Railroads need men for this important work. Big positions open throughout United States. Big ‘ee Book tells all about it—tells how you catt get Write for it— tl Today—Now! Dept. of Signaling, Room $205,1810 Wilson Av., Chicago he exact training you need. Send You a Lachnite ON,T send a penny. Send your name and finger size and say, **Send mea La Lachnite Tmounted in @ solid gold ring on 10 —s free trial.’’ We will send it prepaid right to your home. When it comes merely deposit $4.75 with the post- man and then wear the ring for 10 full days. you, or any 04 your Stones can — i from a diamond. send back. you retarn the ring in lays we w turn your deposit. If you decide to buy—send 62.50 a month until $18.76 is paid. e Send your name now. Tell us which of Write Today jroaiiicciininss iiustrated above you wish [ladies’ or men’s}. Be sure to send your finger size. Harold Lachman Co., 12 N. Michigan Av., Dept. 1206. Chicago ee eee ee ake é Fg + Pn eS gh ee SS ON MT a ae

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Bigger Future More Money Better Positions Opened to -You by This Book } Automobile Electric work today opens the greatest field for young men. With the addition of electric starting and lighting systems on all cars, this year the need for trained men will increase over 100%. Auto mechanics, demonstrators, as well as young men seeking a big future should prepare for this big work. _It pays fine wages and has a limitless future. The heart of the auto electric system is the storage battery. Learn this and know its troubles and you have learned _ the most vital and necessary part of the work. Get this book today and make your start to better, bigger wages— AUTOMOBILE STORAGE BATTERY Its Care and Repair The most authoritative work on the construc- tion, care and repair of the storage battery. Tells in simple, easily understood words howa battery is made: how and why it ‘“‘stores’’ elec- tricity: what the chemical action and the elec- trical action in the battery are and what they must be to have the battery act properly. Tells how to fit up a battery shop: how to ar- range the special benches: how to handle the batteries: to charge them and to discharge them: how to open them up and to put them together. Tells what all the troubles of a battery are; how to locate them and diagnose them and—best of all—it tells just how to repair the batteries and correct any trouble. So complete and so easily understood that it is endorsed by all big battery manufacturers. 5-DAY EXAMINATION Mail us $5 with your name and address, and we will send this 284 page fully illustrated, leather bound book for your examination. If, in 5 days, you don’t think it the best investment you ever made—send the book back and we will immedi- ately return your $5. Better start your big future NOW, without any risk. American Bureau of Engineering 405 Gunther Bldg. CHICAGO Makers of the famous AMBU Electric Trouble Shooter GENTLEMEN: Enclosed find $5.00 (Check--M. O.—Currency) for which send me ‘‘Automobile Storage Bat- tery’’ for examination. If it is not the book I want I will return it in 5 days, and you are to refund the $5.00. A Hundred Tons of Hay in One Stack O stack one hundred tons of hay in one pile without moving the derrick is a simple matter if the derrick is one of the telescopic sort here il- lustrated. There were approximately ninety- three tons of alfalfa hay in this stack, which was inspected on a farm in Richardson County, Neb. The stacking was done with an ordinary double- harpoon hay-fork ona cable carrier running on a steel cable supported by three two-legged towers. The stack is begun next to the middle tower, and built in sections of 36 ft. Popular Science M onthly “Some stack,’’ you say, but it’s merely the simple method employed in piling the hay that accomplishes this feat eachinlength. Each section is topped out before a new one is begun; then the carrier-stop on the cable is moved out 36 ft. farther toward the end tower, and the process repeated. An equipment of this kind provides for a variable crop, and reduces to a mini- mum the time spent in adjusting derricks, etc. Stout poles are best for the con- struction of the towers. The poles best suited to this work are 25 ft. in length, set 3 ft. in the ground. The end towers are securely cross-braced. The cable is carried over the tops of the end towers and anchored firmly to the ground by means of heavy stakes driven deeply into the ground—or, better still, by fastening to a tree if possible.—A. A. JEFFREYS. Don’t Wait for Somebody to Get Hurt CCIDENTS are usually caused by little things, such as projecting boards with nails, pieces of upstanding glass, piles of rubbish about premises, unguarded machinery, stores that are piled carelessly and liable to fall, holes in platforms and floors, weak ladders, loose hammer-heads, sewers left open, absence of signals or other protection. These are the things that most men walk over and around and see every day, but that they do not think to remedy until someone gets hurt or killed. Get into the habit of watching for the little things, and the big things will take care of themselves:—FRED GILMAN. 126 Typewriter Sensation Free Trial eam Use as You Pay a * ; Only $4.00 a month price of v $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 $50.35. 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 Rick—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 areconvinced that it is the best typewriter you ever saw, keep it and send me} .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 return express charges. 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, a8 described in this advertisement. 1 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.

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yours type- ent a 10nth ing a price, y like 10 = | =R ull 84 The le at -color back aring style ience. com- cand oaper mnot auti- l you thou- Model e and risfied ly up - trial nd it s’ free re not type- Irn it eturn il this t in hicago go, tll. cago, as you the rice, at main in I have ewriter. it and od that May, 1919 j Wes |S = ' dotted line, then fold . Ception of the library A New Way of Developing Photographic Film NE of the best methods of de- Oirclonine photographic film is the time and temperature method; but not all of us can afford the daylight developing tank. The following meth- od has all the advantages of the tank method except one: it is not a daylight m. This means that the con- tainer must be charged in the dark- room. It has one advantage over the daylight system: it enables us to fol- low the development by observation. The films are curled and inserted in a glass tube with the emulsion side in. The glass tube is provided with two stoppers. The lower one remains permanently in the tube, while the upper one is re- placed after the de- veloping solution has been poured into the tube. A card- board tube used for mailing drawings is then slipped over the glass tube, and caps are fitted to the ends of the cardboard tube. The person doing the developing can then leave the room until the time of the development is complete. Later the develop- ing solution is emp- tied and the glass It is quickly tube is filled with the developed in fixing solution. After the tube fixing is complete the film can be washed in the tube, and it need not be touched until it is ready for drying. There is very little chance of the sensitive surface of the film being damaged; and when small films are enlarged this is an important consider- ation.—C. A. OLDROYD. When You Can’t Find a Single Envelope ‘| ‘HOUGH there is an envelope on the market similar to this one, the sketches herewith show how quickly one can be made from the ordinary size business letter-heads, using only a pocket- knife or scissors. After foldine as in Fig. 2, cut off on the the surplus ends as In Fig. 8, and cut them off on the fold, thus completing the envelope, with the ex- ric.s. paste, which is applied = 7 radar to the flap when it is Teady for sealing.—R.. J. STEVENS. “POSITION | SALARY ENGINEER | L2o Wet REPAIR MAN |*5Q) wit CHAUFFEUR |°5Q() wit 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-the-minute five-volume library on Automobile Engineering, covering the con- struction, care and repair of pleasure cars, motor trucks and motorcycles. Brimming over with advanced information on Lighting Systems, Garage Design and peseakne Diiniien Equipment, Welding and other repair methods. Con-_ | Tires Vulcanizing ry Partial List of Contents Explosion Motors Welding Motor Construction and Repair Carburetcrs and Settings Valves, Cooling Lubrication Fly-Wheels Clutch Transmission tains everything that a mechanic or an engineer or a nas ee oe a ry . a n motorcyclist or the owner or prospective owner of a Systems motor car ought to know. Written in simple language | Siting Diagrams Commercial Garage Design and Equipment Electrics Storage Batteries Care and Repair Motorcycles Commercial Trucks Glossary that anybody can understand. Tastefully bound in American Morocco, flexible covers, gold stamped, 2,400 pages and 2,000 illustrations, tables and explanatory dia- grams. A library that cost thousands of dollars, to com- pile but that comes to you free for 7 days’ examination. Only Tc a Day Not a cent to pay in advance. First you see the books in your own home or shop. 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 you want to keep them or not. If you like the books send only $2 ‘in 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 consulting membership in the American Technical Society. (Regular price $12.) This great bargain offer must soon be withdrawn. Send No Money Now Don’t take our word for it. See the books without cost. There is so much profit in this 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 money—only the coupon! American Technical Society Dept. A-1205, Chicago, II. American Technical Society, Dept. A-1205, Chicago, Il. 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 witnin 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 3 for. If I think I can get along without the books after =ai With every set ts included — FREE eal —a Consulting Membership which z gives you the privilege of submit- ting your perplexing problems to =a4] a corps of experts for an entire year. fast This Consulting Membership regu- larly sells for $12.00. the seven days’ trial I will return them at your expense. 127 i e ¥ Hy ha Oi a { Ma ' {

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The Cleveland Lightweight LENDING lightweight with low cost, the CLEVELAND still has no rival among motor- cycles. It stands alone in its scientific combi- nation of li ight weight and power. The 1919 CLEVELAND is retaining the same principles of ep design that have made it successful for four Sanet--but this year’s model is a finer ma- chine than ever befsre--fa appearance—comfort and service. The only lightweight motor- cycle adopted by the United States War Department. Two Stroke Motor Unit Power Plant orm Drive Transmission Standard for four years. Write for 5 and agency. (One dealer sold six carloads last summer. The Cleveland é >) © Motorcycle Mfg. Co, z

Cleveland, U.S.A,

American Box Ball Built This Home!

Small Investment Big Rewards TARTING with $150, C. T. Patterson, of Illi- nois, made $800.70 in the first two months from American Box Ball. Now operates eight alleys. Nine years of success. Ameri- can Box Ball Bowling is the sport that never grows old. Today’s opportunity is greater than ever. Clos- ing 300,000 saloons brings nation-wide demand for Box Ball Alleys. ' Released soldiers want this delightful ex- ercise. Workers, merchants, everyone wants it. Box Ball $e gees old and young. $12 to $18 a day from two alleys is common. acedsoike earn more.- Do as Patterson and many others have done. Little money to start. Part down— balance out of profits. We help you. This is the right time to start. Write for our money-making proposition. Send now. American Box Ball Co. 601 Van Buren St. Indianapolis, ind. = MotoRS y We have 1000 NEW WASHING MACHINE MOTORS. These 4 he regular lactory guarantee i) Shipped tn ore Saad beeen ane Bought from Ruskrepicy Stock Suitable for operating Coffee Grinders, Cream Seperators, Bottle Washers, Compressors Small Lathes, [p4ait $3.00 cash_or Ete Money Order We send COD saihyer re toch emmiantion 4

1/4 oo sie

**Hamilton’’ Improved Slide Rule in- stantly adds, subtracts. divides, mul- ~ lies, converts fractions or decimals an inch or both. Gives sines,co-sines ve sines,co-versed sines, tangents co-tangents’ secants, co-seeants of angles. Square root. , cube Foot, roots to “the fifth powers,’ logarith: cir- Hil] Cumferences, area ‘and diameters of ™ circles. Mos st complete slide rule of W its kind evermade. This rule is five and four- tenths inches in ie. In- structions with each rule. UTILITY RUL ES. 1.00. SPECIAL DE LUXE, whi celluloid | $2.50, postpaid. ‘Agen ts and dealers wanted. J.C. I ag itton & C Sprost Dept. <3 Boston, "Mase water A.

This Hoist Is Operated by the Weight of Water Y utilizing the power of gravity with a large stock tank, a hose, and running water, combined as shown, a Nevada farmer has provided himself with the means of lifting loads of two tons or less, working single-handed and with practically no muscular exertion. The farm is an irrigated one, and running water is supplied from a near- by mountain stream by gravity pres- sure. This is piped into the barn and to the tank by means of a hose through the loft door, near which the hoisting mechanism is used chiefly for hoist- ing hay and sacks of grain into the loft. The tackle is swung from the pro- jecting eaves of the barn, and the lower end is provided with several attachments that may be instantly re- moved or applied. These consist of a hay-hook, a platform for lifting sacks

HYDRANT Water weight provides the mo- tive power for this gravity hoist of grain, and a connecting hook by which the power created by hydraulic weight may be conveyed to other points about the farm merely by attaching a cable. If it is a ton of hay that the farmer has hauled from the field and wishes to store in his barn, he has only to drive the hay-hook to the tackle, and set the jaws in the load. He then goes to the loft, opens a valve, and starts the water flowing into the tank. When- ever the weight of the water in the tank becomes greater than the weight of the load to be hoisted, up goes the hay, grain, or whatever the load may consist of. The water is then turned off, the load is run into the loft, and the water that was used for producing the weight is run off into the nearest irrigating-ditch. It is obvious that the lifting power of this type of hoist is limited only by the dimensions of the equipment used and that it may be made to do many things about the farm. ‘Genius’ seems to be the Western farmer’s middle name these days, for he is coming to the fore with crops and finventions that spell riches for him. —JOHN E. Hoae. 128

Popular Science Monthly WOR SEND FOR THIS ox Waa ait BOOK -

Tells how to make dosens of motor repairs easily, quickly, eco- nomically with SMOOTH-ON IRON CEMENT No.1 The book isfree. Write for it. The Cement is 25c for 6 oz. can, 50¢ for 12 02. can. At Hardware and Supply Stores. SMOOTH-ON MFG. CO., Jersey City,N.J.,U.S.A. SMOOTH-ON IRON CEMENT

. Perfect hearing is now stored in every contin of fet p ness or ae hearin ’ causes such as Cata that De ness, Relaxed or Sunken _Thickened Drums, een Drang sa’ Hissing Sounds, Perfora Wholly or Partially Destrosed 22, Drums,Discharge from Ears, etc, Wilson Deiapnationes Ear Drums ‘Little Wireless Phones for the Ears’? require no medicine but effectively replace what is lacking or defective in thenaturaleardrums, They are simple devices, which the wearer easily fits into the ears where they are invisible. » Safe and comfortable. Write today for our 168 page FREE book on DEAF: ' spend you full particulars and testimonials, WILSON EAR DRUM CO.., Incorporated 905 enter Howtnesa Bldg. LOUISVILLE, KY, Pilliod TOOL CASES EXCEL Machinists and Too! Makers find them most satisfactory in construction, appearance, service and price. Imme- diate shipment. Booklet pte d 20 styles The Pilliod Lamberts Dept. A, Swanton, Ohio COMPLETE MARKING OUTFIT Just What You Need for Marking Tools NO TOOLS TOO HARD Price - $1.00 Postage = 5c. J. M. WATERSTON 81 Woodward Ave., DETROIT, MICH. | | TEACH a) Stn OL I won World’s First Prize for best course in Penmanship. Under my guidance you — become an expert penman. Am placing many of my students as instructors in commercial colleges at hig’ salaries. If you wish to. become a better penman, write me, I will send you FREE one of my Favorite ‘Pens and a copy of the Ransomerian Journal. Write today. C. W. RANSOM, 488 Essex Bldg., Kansas City, Mo. 1 £90t0°250.aMonth] FreeBoolclells How ‘Write today for this big, new Free Book on SIGNAL ENGINEERING Railroads need men for this § portant t work. Bie sitions 0) d States. Free Book Fils allabout it—tells how youeem fr : the exact training you need. Write f Today—Now! Dept. of Signaling, Room 9205,1810 Wilson Av., Chicago ppt aga tr PROFITS START GROWING MUSHROOMS Learn the latest authoritative way to make still bigger profits than you ever thought possible Se ever made growing myshr rooms. Add $10 to $75 a week to your ‘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 Suthority, **The Truth About Mushrooms.’’ Write to BUREAU = Bag meagre INDUSTRY Dept. 552 5 W. North Ave. Chicago concrete re- -inforce- ) ) IR ment, springs. net- ting, wire fences, steel posts, trolley-road wires and rail bonds, wire wheels, auto-towing cables, horse-shoes. Iliustrated Books Describing Uses, FREE F LBAACKES, American Steel & Wire Co.¥: Lat

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electrical, rope, air- plane, piano, pipe- organ, flat, hoops. bale - ties, tacks, nails, barbed-wire,

ae ated alt Dekh ae Oo

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a” BaBeRREEs CQ | eo 88 | BBRSE R 2.

big free h About ‘hicago

De, air- , pipe- hoops. tacks, i-wire, 1 force- s, net- nd rail shoes.

‘May, 1919 Cutting Patterns for Screw- Threads in a Triangle RAFTSMEN whose work entails D the drawing of many bolts and screws can lighten their labor con- siderably by cutting the patterns for several standard-gage threads habit- ually used along the edges of the cut-out portion of triangles. Over each pat- tern, which should consist of about half a dozen teeth, write with indelible ink the correct gage. H This is not gener- ally known or prac- tised and is a great time- and labor- saver. To use it, simply lay the desired sized pattern along the line marked on the edge with a sharp pencil.—L. B. ROBBINS.

A Counter-Weight to Hold Up the Window-Screen HEN a window is screened, the lowering or raising of the awn- ing is always very awkward, making it necessary to keep a stick at hand with which to prop up the screen. An excellent way to avoid this is to attach a cord to the lower screen at the center of the upper edge, run it up over a pulley at the top of the window- frame, and then attach a wooden handle to the lower end, allowing the cord to project from below in the form of a loop, as shown in the illustration. A stout wood-screw should then be set in the lower member of the screen frame so as to project about %¢ in. To raise a screen so equipped, it is necessary to use only one hand, as it

Projecting knob The many who have jammed their fingers by forgetting that an un- weighted screen won’t stay up, will no doubt, adopt this contrivance is a simple matter to pull on the handle until it comes opposite the projecting screw, over which the loop is then hooked. It is always easier to pull a given weight than to lift, and when one desires merely to lower the awning, it is not even necessary to hook the cord on the screw, as the screen is easily held up while the other hand re- leases the awning rope. _

the Automobile Center of the World is the Logical CO mm Place to

The Automobile and Tractor indus- tries offer you greater op- portunities than ever before. Now that the war is over, the fac- tories are again building autos, trucks and tractors. It is reported that the Ford Motor Company alone has orders ahead for 250,000 to _ 300,000 cars, not including trucks. It is saidthat Dodge, Buick, Cadillac, Packard, and many others have enough un- filled orders on hand to keep going at full speed day and night for months. Tractor factories are also behind on orders. Thousands of trained auto and tractor men are needed. Get ready to enter a success- ful and profitable life work. Earn $100 to $400 a Month Hold down a good job or go into business for yourself. We can teach you in a few short weeks to handle any auto or tractor proposition. Our garage repair shop has from twenty to thirty-five cars for you to work on. Different cars go and come every day. In our block test department alone, we have twenty-five different types of motors. We have absolutely the best equipment obtainable.

Factories Endorse Our School The leading automobile factories in Detroit and other cities endorse our school, our equipment and our methods of teaching. Read some of their endorsements on this page. Tractor Course Included In Auto Course With the co-operation of the International Harvester Co. and our complete tractor equipment, every man 2 who takes the complete Auto course ts thoroughly T hese were written in reply to letters from different parts equipped to handle every Tractor Problem. Tractor instruc- of the country asking about us. tions are included with the Auto course at the same tuition. Courses Also In Brazing, Welding, Tire Repairing Letters from Factories In addition to our general automobile course, we give separate | The Michigan State Auto Schoo} enjoys a very enviehle and complete courses in Brazing and Welding and Tire Repair- fhe United States’ I have no hesitation in cecatnend: ing. With over five million cars in use and four or five tires per ing it in every particular. car, there is a lot of money in repairing tires. Brazers and PACER ED MOTOR CAR COMPANY Welders are getting $8.00 and $10.00 per day. Factories and ors Sa t garages are always looking for these men too. inet ae A pte Seb eels “= f ge oy fy ye 7 aware, its course of instruction is thorough, compre- Not a One Man School Earn While You Learn hensive and practical. In fact, we endorse its method of This school is founded on the If necessary we can secure work for tuition. best, most practical and new- We have recommended a great many students to them est principles, in the Automo- you to help pay expenses while you are n¢ the results were very satisfactory. plates teasineaas Itistheresultof taking our courses. HUDSON MOTOR’ CAR COMPANY. the keenest co-operation with in : . manufacturers, service sta- Detroit Is Place to Learn, You Pd v4 cep bam agp: ey tosey eset Can Start Any Time ‘ fract San oma idee bat the hesitate te recommend it, to anyone who is-desirous of i . . H * odie e8s. ideas idee be al ee Detroit. trained men get preference ings tations among the automobile factories of this city. field. “A. G. Zeller, Pres. and get jobs quickly. No other city our employ aud every abe fae tives cote tee can give what Detroit does with its Very truly yours more than 184 large Auto and acces- MAXWELL MOTOR COMPANY, Inc. We guarantee to qualify A . . . CHALMERS PLANT, you for a position as chauf- sories factories. Think what it means H. H. Leg, Supervisor Welfare and Labor. : to learn in the Michigan State Auto . t 2 feur, repair man, tester, - ; Your = damseuetentan, auto electri: School. 71% of autos made in Detroit. commendable for be pte Ft Fy wen cian, garage man, automo- We havea SpragueElectricDynamom- 4 Ser a ecastal ideas to be had. 2 bile dealer, Aeroplane mo- eter. School openallthe year. Winter Auto Schoo eesush cos sinpiy Genamben’ isthe United tor mechanic or tractor me, Classes any time, and day. Three Suurtal"mMcyom, tamer ereusen: hore J09 from $100 to $400 monthly Classes daily, morning, afternoon, eve- wages. Var Uintvenoe or refund your money. ning. INTERNATIONAL HARVESTER COMPANY DETROIT FREE—New 176 Page Catalog 2 Fill in the coupon; get the F THE HEART OF THEAUTOINDUSTRY «Auto School News” and New 176-Page Illustrated Catalog, showing 133 illustrations, letters from graduates and big factories. All, absolutely free. Or better i Gentle e ROT: MICHIGAN, U. 8. A. still, jump on the train, as hun- entlemen: Please send me, absolutely FREE, New dreds have done, and come to the ] and Information ac cheake, pepe ais Money-Back Guarantee Send This Coupon Today, MICHIGAN STATE AUTO SCHOOL 585 Auto Bidg., 687-89-91 Woodward Ave. “Heart of the Automobile Indus- § () AutoandTractor {[] Tire Repairing try” and learn right. a il whe L£,e Michigan State Auto School Or, better still, you can expect me about

The Old R Ji ble School—A. G. Zeller, Pres TTT HHH HEHEHE EH EEE CHEESES ~ AUTOMOBILES, TRUCKS, | NMi@es cc evoce CO ccccccccccceederececsecencs Z< 140 pies mee arnae vane ay aaihce AUTOMOBILE accessory 585 Auto Bldg., 687-89-91 ward Ave. | kv ensVccecvccencoesceenegneeheketeenun sctonies -< CEWTE™ FACTORIES DETROIT, MICH., U.S. A.

COO e reer eres s ees ees smalls sess seseses

Build Your Own Grandfather’s Clock | with our help Olt 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.

We furnish blue prints, fin- ishing material and instruc- tions. Buy the works, dial, weights and pendulum from us at surprisingly low prices. You make a profit building artistic

Owners of the world’s largest Asbestos Mines. clocks for your friends. Complete Works $5.00 Others with chimes at all prices f i oom om TOOL CASES Ask for attractive Free Offer CLOCK COMPANY 1663 Ruffner St. Philadelphia, Pa. First ; for Machinists and Toolmakers Write for our booklet showing the best built and most practical selec- tion of Tool Cases on the market, We ship direct from factory and guarantee to please you or refund AGersluer ident. re ‘ S50 Columbia St., Daytoh, onio

USE HB BALL BEARING |e oy B23 Cem Cons) es _— ee serie on lost power from central power instal- ° e ations. se sturdy, dependable HB Motors to run single The New Midget Slide Rule machines or groups. Economical and efficient. Amply rated. Sizes for all requirements from 4 to 15H. P. Built to lower has many exclusive features. It your power cost. Easy to install and operate, require practically will add and subtract fractions no attention. ? and give decimal equivalents. It will also multiply, divide, add and subtract, solve problems involving any root or ower (excepting —1) and will give garithms and the Sines, Tangents, Cosines and Cotangents of all angles.

Write Tcday for Prices and terms on HB Moto e your needs. Let our engineers agree tors to meet y ~ you. or easy payments. Sta a metal. ize 3 inches. \ z in- Send for free circulars. Price 1.00 ; pb niger available and Rind Of machin- with complete instructions. Your money bac 1 wish to 4 you eve mat facture HB Battery Chargers, Lighting Generators, etc. Write today for in- formation. Pin this ad to your letter-

satisfied. GILSON SLIDE RULE CO., Niles, Mich.

HOBART BROTHERS COMPANY Box S5 ‘Troy, Ohio Sucesssful Manufacturers Since 1893 THE BOY ELECTRICIAN. Popular Plans of Electrical Apparatus for Work and Play with an Explanation of the Principles of Every-day Electricitv. $2.00 Postpaid. Popular Science Monthly, 225 W. 39th Street, New York 129

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MOSSBERG | ALL STEEL” WRENCHES AND TOOLS Leadership in the manufacture of wrenches and tools has been gained ’ and maintained through adherence to principles of manufacture which in- sure to the user of Mossberg products the utmost in value and in service. Illustrated here are: Mossberg All Steel Socket Set No. 45, containing an assortment of 15 sock- ets, universal joint and speed brace. K-9 and 74 adjustable wrenches; also solid handle wrenches 6 and 12 inch with speed brace. No. 4 Garage Set of Open-end Wrenches; one opening of each wrench fitting U. S. standard bolts, and the other opening of the same wrench fitting S. A. E. cap screws of the same dimension. Send for complete catalogue and particulars FRANK MOSSBERG CO WRENCHSMITHS FOR 20 YEARS ATTLEBORO, MASS. U.S.A SSS NS SNS SS Do Your Soldering Without the Plumber OLDERING is one of the easiest operations, and its applications for both temporary and permanent work about the house, farm, and work- shop are almost endless. The main thing to remember is that the surface to be joined together by or patched with solder must be thoroughly clean. To attempt to solder a dirt surface is about as tedious and unsatisfactory an operation as can be imagined. Then comes the question of a flux, and it is well to say in passing that the function of a flux is to keep the metal surfaces clean and exclude the oxygen of the atmosphere. For things that can be well washed after they have been soldered, zine chloride is the best flux. This is made by dissolving zinc in hydrochloric acid until the acid will dissolve no more. Better keep a small piece of zinc in the solution, as it precipitates the copper with which the solution becomes contaminated be- cause of the continual dipping of the point of the soldering copper in it. For the soldering of electric wiring, however, which cannot be thoroughly washed, resin must be used as a flux; for, if zine chloride is not thoroughly washed off copper and iron, it starts corrosion, which is continued by atmos- pheric influences, finally eating com- pletely through the wire and causing no end of trouble. Before You Start Before starting to solder anything, see that the point of the sofdering copper is well “‘tinned,”’ that is, well covered with solder. This is accom- plished by cleaning it thoroughly on coarse sandpaper or on a board with coarse sand on it, or, if it is badly corroded, by filing it with a coarse file. Having cleaned it, dip the point of the copper in the zinc chloride, heat it to a little above the melting-point of the solder, dip it momentarily in the flux again, and rub the point on the solder until the four sides are well covered with the material. ' In soldering two things together, it is well first to “‘tin’’ the surface to be joined. It makes the operation easier and gives a better joint. This is done by first moistening the surfaces with the soldering flux, and then with the heated soldering copper, rubbing the molten solder over the surfaces until it adheres to them. Care should be taken not to have an excess of solder on the surfaces; that is, they should not be lumpy. The two pieces to be joined are again moistened with the flux, placed in the desired position, and heated with the soldering copper until the solder melts. The surplus solder pieces are held in position by pincers or job.—_F. H. SwEEtT. 130 A Good, All-Around Tool Bag Made of Harness Leather— Strong and Durable—6 Sizes Combines all the good features of the vari- ous 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 and pad. A mighty good all-around tool bag. Six sizes ranging from I4x8 inches to 24x8 inches. Show this ad to your dealer and ask for the genuine KLEIN tool bag. If unable to get it write us, KLEIN’S Oblique Cutting Plier Electricians, tele- phone men and switchboard builders will find this particular oblique cutting plier one of the most useful tools Mf in their kits.BEF Cuts clean and#iG close, the narrowfif head permitting its use in confined places. Carried Wf by dealers every- where. Catalog sent you on request. MATHIAS KLEIN & SONS, Mfrs. CANAL STA. 3, CHICAGO KEROSENE ENGINES | Start Easy inany weather, Pull steady. —— zasy Carry big overload. All sizes endstyles. 1/4 H-P. to 22 H-P. 90 Days’ Trial. Money Back Guarantce. Prompt shipment. Pri Write for it m Bavil Low gnoces prices and Free Book, telling all you want to know aboutengines. Write today. OTTAWA MFG. CO. ortawa’ Kane: oo . is squeezed out by pressure, and the by some other means until the solder sets. A little solder can be run round the edges of the joint to make a neat GOOD IDEAS AND INVENTIONS Can be coined intc money.—LET US HELP YOU. . od Our Factory, Development, Equipment and Sz Manufacturing Depar:ments et your service. > Expert advice and help in marketing articles. ¢ /Make The “Ideal”? Your Factory. Our valuable booklet free to those interested. I AL MACHINE & TOoLG 128-130 OperaPlace CINCINNATI,O. Dept 18 a a ey a = © ctr o> = © ee i ae ae a ae, a

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pe May, 1919 A Good Home-Made Folding ; Easel REtwopieces of 3-in. lumber, Pe eatly pine, and cut them into pieces 28 in. and 27 in. in length. These pieces are to form the base of the easel, and may, if desired, be rounded at the corners or left square, as preferred. The long piece of pine is halved in the center, while the short piece is halved at the end, which will then fit into the long plece. These ends may be mortised if desired, as this method makes a more substantial pase for the easel. After securely bolting ; these two pieces together, the base is complete and ready for the upright. The up- right is made of the same material about 5 ft. in length of 1 x 3-in. pine. ENLARGED SLOT IN HASP FOR FRONT AND BACK |) = EASEL TOP SLIDE An artist can make it from easily purchased materials Drill holes 6 in. apart from the top in the center of the upright to within 8 in. of the bottom to take a 14-in. pin. Set this upright on the base, and screw fast with a 7- or 8-in. strap- hinge, as shown. Now fix a brace in the rear end of the base, which is also fastened with a hinge. An enlarged slot allows for the forward and back- ward movement of the easel. Screw a rasp into'place, and drill a hole into the upright to accommodate a small stove bolt with a wing-nut and washer, the wing-nut being set in the back through the opening in the hasp. The slides are made of small strips of brass bent into the shape shown in the sketch and screwed into small blocks of the same thickness as the uprights. The lower slide is held in place by the pin inserted into the Y-in. hole. The top slide does not need any- thing but its own weight to hold the Canvas, and can be raised or lowered. letals Require ack Saw Blades If you want to cut structural steel or brass pipe efficiently, you need a different hack saw than for cast iron or machine steel, and you certainly can’t work as coarse a blade in a light machine as in a heavy one. To try to do everything with the same blade is simply to do most of it inefficiently. Starrett do the most work with the least effort in the shortest time because each one is made to meet the exact requirements of different metals in different powered machines. Write us today. Ask for Catalog No. 2/W wey ees] eee THE L. S. STARRETT COMPANY [= The World’s Greatest Toolmakers Manufacturers of Hack Saws Unexcelled == ATHOL, MASS. Our Hack Saw Chart will help you select the proper blade for any kind of work, and you can depend upon it. Our Service De- partment will help you solve your cutting problems and increase the efh- ciency of your cut- ° ting-off department. 6 Starrett @ Pee | Lge | ate Sawn | aoe = jw eye) |e lela e eel eel & [ele NEW YORK LONDON CHICAGO [= 5 = 42.908 MATT seis ee tn BUY FOR LES Easy Terms Write for Reduced Prices on WITTE Engines all sizes—2 to 30 H-P.—Kero- my money saving offer. I make engines— guarantee longer—sell for less.— Valuable Book FREE.—Ed. H. Witte, Pres E ENGINE WORKS 2226 Oakland Ave., Kansas City, Mo. 2226 Empire Bidg., Pittsburgh, Pa, Genuine Armstrong Stocks and Dies Have You a Set in Your Kit? +} Some of the advantages of Genuine ARM- STRONG Stocks and Dies: , They can be adjusted to the variations in the size of fittings. Resultsare accomplished with lessworkandtime. The Dies are interchangeable in the stocks and they can be sharpened without drawingthe temper. Our catalog tells the rest of this interesting story; send for it to-day. THE ARMSTRONG MFG. CO. 337 Kriowlton Street - Bridgeport, Conn. 131 \ Make Big Profits in Battery Charging $150 to $250 Clear Profit Each Month recharging auto storage batteries. The HB 16-Bat- tery Charger recharges 1 to 16 6-volt batteries or their equivalent at once with current cost of 12¢ to 15c per battery. Motorist pays 75c to $1.50. Figure your profits! This season means bigger battery business than ever—more old cars driven—new Fords to have storage batteries. Get busy now! Don’t delay! Start after those profits! $57 Puts This Money - Maker in Your Garage on Money-Back Guarantee Balance in 10 monthly payments of $23 each. Earn- ings pay for machine. No electrical knowledge neces- sary to operate. Uses 2 or 3 phase city current. Furnished complete with 2 charging panels capable of charging 1 to 8 batteries each. No adjustments or expensive renewals. Big, permanent profits. Sold on HB Absolute Money-Back Guarantee. Order Now—yourun no risk. Pin your check to this ad and mail today.for trial order. Do it NOW! Hobart Brothers Company, Box S5, Troy, Ohio Successful Manufacturers Since 1893 ih LP

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“HURWOOD” Screw Drivers Unsurpassed for Strength and Durability Blade, Shank and Head— one piece of special steel, finely tempered. The blade cannot turn in the handle. The assortment illustrated above is well worth your at- tention. For instance—No. 21 shown at the extreme right of the pic- ture—blade only 11% inches long, just fits the vest pocket, a strong little Driver and very handy. Also No. 60—shown at the left—only 15% inch blade, but with a big sure grip handle. For heavy work into close cor- nerfs it cannot be beaten. Used by Plumbers, Machinists, Mill- wrights, etc. Nos. 51, 52 and 53—called MACHINISTS’ DRIVERS —hbig, broad tips for large screws and extra large shanks for heavy work. Nos. 5114, 5214 and 53144— also Machinists’ Drivers, have hexagon nut on shank for use with a wrench. No.54—Note the DOUBLE GRIP, also the hexagon fea- ture for wrench. With the latter Driver one can turn anything. We make many other drivers. See Catalog No. 34S. At All Hardware Dealers STANLEY RuLE & Lever Co. New Britain, Conn. U.S.A. A Mixing-Valve to Take the Place of a Carburetor NE encounters many troubles in the ordinary float-feed carbure- tor, especially on low-speed engines such as marine or industrial types. In experimenting with various engines it was found to be more expedient to use a mixing-valve than the average carburetor. While there are numerous contriv- ances of this sort sold, the valve can be easily and cheaply made by almost anyone. Of course, everybody knows that gasoline and air must be mixed to proper proportions to make a com- bustible gas. To accomplish this, it is necessary to have a gas inlet and an air inlet, both of which must be adjustable. In starting the engine with the mixing-valve installed, it is highly important that the gasoline valve be opened, while the air inlet is closed. As the engine starts firing, the air inlet is gradually opened until the engine takes its charge without back- firing or choking, at which time it is TO MOTOR ® INLET PORT saws Saud AN — AiR MIXES Daun DAIR-INTAKE Doing the work of the high-priced car- buretor, a home-make mixing-valve will save money for the small launch owner utilizing the gasoline at its highest point of efficiency. When the engine is stopped the gasoline valve must be closed, to prevent the gasoline from dripping through. To make this device, ascertain the diameter of the inlet port, procure a standard pipe Tee of equal diameter, and drill through its bottom outlet a Yin. hole, penetrating both walls of the Tee. Insert therein a butterfly valve made from a piece of No. 16 gage sheet-iron cut to fit the inside of the pipe and soldered to the axis, which is made of a nail Y in. in diameter. To this solder a_ brass spring held in its required position by notches filed in the side of the Tee, the edges of the arm being bent inward so that it engages the notch to assure the desired position. This arm or air- regulating lever is made from 1-16-in. spring brass soldered to the nail axle. bushing which has a reducer thread of 14 in., into which is fitted that size nipple. This nipple is threaded its entire length. After the nipple is screwed into the bushing, a cap is affixed to its end, through the center of which is drilled a 1-64-in. hole. On 132 The inlet of the Tee is fitted with a | Popular Science Mons The limit has never been found to the number of things you can do with i 7X & Pen iss oaT once PLIERS They are truly your “Etc.” saab tools. Repair: pool Every day you _" find new uses, pevtes find yourself do- ts ing things around ie the house with — ““Red Devils” Pull: that you thought Take you couldn’t do eaten yourself. Turn: Ask your hard- Valves Kers ware dealer to Etc. sell you the par- Make: , | ticular kind of Hat Frames “Red Devils’’ tc. . . ai which will serve Wir you best —and Ete. put them towork today. SMITH & HEMENWAY CO., INC. | 264 Broadway, New York City Factories: Irvington, N. J. **Red Devil’’ is the Expert Mechanic's guide to Known Quality in Pliers,Electricians’ Tools, Hack Saw Frames and Blades, Auger Bits, Chain Drills, and other Hand Tools, all ofa class with ‘‘Red Devil’’ Glass Cutters, the biggest sellers in the world. De ee New Catalog Illustrating and describing the very latest and best in nS DeFOREST We Radio 23 ne = Apparatus SVSTEM SS pie BEY Discriminating aah i a for s ready ARRAY mailing Complete le regarding the De Forest “Unit’’ Set, “‘Honey Comb” Coils (a radical de- parture from previous forms of apparatus), variable air and fixed condensers, wavemeters, variometers, detectors, etc. Will be sent upon receipt of 10¢\to defray postage. De Forest Radio Tel. & Tel. Co. 1391 Sedgwick Ave. New York City

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ard- to Dar- ils”? {rve and rork INC. ity uide ools, B 11 ofa ts, the trating ind ibing the latest best in adio aratus for — iminating Jsers ady for ailing e Forest dical de- yaratus), emeters, ‘nt upon 1. Co. May, 1919 rk City ten enn enn ide of the reducer nipple is Breas YA. valve, to which is con- nected the gasoline supply. A butterfly throttle valve may be fitted into the intake nipple, but a very good throttle is obtained by the use of the air-valve. This is done at the expense, more or less, of the gasoline consumption; but by the use of the putterfly throttle the entire pipe vacuum or suction may be so regulated that its efficiency is 100 per cent. This mixing-valve is especially adapted to engines of 500 to 1000 revolutions per minute, and it will be found to be extremely easy starting on " engines of this kind.—P. P. AVERY. Home-Made Scraper Blades for Carpenters T will pay any carpenter who has to do finishing to go to the trouble of making himself three or four narrow scraper blades similar to those here illustrated. Three or four such scrapers can be made from one standard 6-in. scraper 2 “, Z ag This type of scrapers offers an excellent hand- hold and will reach all corners in panel work steely and will be found useful in numberless instances where the ordi- nary wide steel is too wide or too large, or else improperly shaped to do the work. Often shallow depressions in panel work or corners can either not be reached at all with an ordinary scraper, or can be worked only with great difficulty. Rounded stock also is ill fitted to be worked with a square blade, and then again shallow rounded depressions need to be worked out where a gouge will not do because it cannot be easily controlled. With the set of narrow blades shown, all these different jobs can be s“tis- factorily performed. Two advantages of these scrapers are that they offer an unusually good hand-hold. Owing to this and to the shortness of the cutting edge, four or five times more pressure can be exerted than with an ordinary Wide blade. In difficult and awkward Places this will be found to be of the utmost importance. By the use of the rounded scraper the rim of a sink or other enamel or ron body can be perfectly scribed into a very good drain-board or table-top. HEnry SIMON. The Saws Used Exclusively by Many of the World’s Largest Saw Mills : Each year finds a greater number of the leading saw mills of the world using ,DISSTON SAWS exclusively. The high quality of DISSTON Band, Circular, and Gang Saws is proven by the excellent results obtained in the actual work. Made of DISSTON CRUCIBLE Steel, the product of the DISSTON Steel Works, of a toughness, strength and elasticity un- surpassed, low cost of lumber production and small repair bills are natural results. DISSTON SAWS have been the leaders for nearly eighty years. When values are compared and saw-mill operators find their preference backed up by the experience of others, the immense growth of this industry, which is now the largest saw manufacturing business in the world, is readily explained. When you need a saw, no matter what purpose it is for, buy a DISSTON, which is backed up by the long, favorable DISSTON record for QUALITY, VALUE and SERVICE. Henry Disston & Sons, Inc., Philadelphia, U.S.A. “America’s Longest Established Makers of Hand Saws, Cross Cut Saws, Band Saws, Circular Saws and Tools” Chicago Cincinnati Boston San Francisco New Orleans Memphis Seattle Portland, Ore. Bangor, Me. Vancouver, B.C. Sydney, Australia CANADIAN WORKS: TORONTO, CANADA ovsS To, 133 DISSTON DISSTON SAWS AND TOOLS Standard for Nearly Eighty Years —and Growing Faster Every Year swag eat

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Service Through the use of these tools you obtain the service that seventy years of experience in tool making offers. The nicety of finish is the visible evidence of quality. That which you can not see—but can always feel is there—is the highgrade accurate workmanship that has been put into every tocl—guaranteeing re- liable results and satis- factory service. Get acquainted with these well-known tools and enjoy the depend- able service they offer you. Brown & Sharpe Mfg. Co. PROVIDENCE, R.I., U.S.A. The Useful Surface Gage— How to Make It “HE surface gage is a very useful tool around a planer or shaper, and it will be found of value in laying out work on surface plates, etc. The vase can be made of cast-iron and turned up in the lathe, recessing -_the bottom as shown in the illustration to give a good bearing. The upright rod is made of a piece of l4-in. die cold rolled steel, the hole it enters in the base reamed to 1/1000 of peri, Acie “= hey +O oe Ei €q DRILL Baer: AL yoa--O The completed surface-gage is a very useful instrument on planers, etc. an inch smaller, thus making a light press fit. The scriber should be made of 5/64- in. die drill-rod, bent at right angles on one end and the points hardened. All the other parts may be made of soft steel, and, after polishing, heated and left immersed in a pot of melted cyanide for about fifteen minutes’ quenching in cold water. Tools should never be ppt away without first wiping them thoroughly all over with an oily rag, to prevent rust. Never pile tools on top of one another. Such carelessness causes dented and scratched surfaces, render- ing the tools inaccurate. The old saying that a good mechanic is known by his tools is as true as ever.—A. DANE. How to Test an Article for Gilt a that is required to recognize whether an articie is gilt or not is to touch it with a glass rod that has been dipped in a solution of bichlo- ride of copper. [If the article has been gilded the spot touched will re- main intact, while it will present a brown stain if no gold is deposited on its surface.—HERMAN NEUHAUS. 134 Popular Science Me io Provide for Low Labor-Cost The high cost of labor for operating machines necesgj- tates a high rate-of-output from your machines—and you equip them for this when you put on Veeder Counters. Veeders are the means of main- taining the best rate-of-work a machine is good for, and their presence on a machine insures labor-eficiency which beats down the cost of production, COUNTERS aid in developing machines no less than in operating them, by registering the results of mechan- ical improvements as they prove up in the production-rate. 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 especial- ly suitable for many types of- small machines. A most adaptable counter for experimental work. (Will subtract if run backward.) Price, $1.75. For recording and checking-up the output of larger machines, such as punch presses, metal-stamping machines and the like, where a reciprocating movement counts an operation, use the Set-Back Rotary Ratchet Counter below. wher Ter (O" [0 Registers one for each throw of the lever, and sets back to zero by turning knob once round. Supplied with from four to ten fig ure-wheels, as required. Price, with four figure-wheels (as illustrated) $12 (list). Free booklet shows ccunters jor more purposes than we can advertise—you ll see just the sizes and styles jor your uses. Shall we send you a copy? The Veeder Mfg. Co. 44 Sargeant St., _ Hartford, Conn.

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their sures eats tion, ‘S$ no n, by: echan- ve up er be- ion of ording a eration. all, this ery tand a f speed, yle for pes of - ines. ptable subtract ip the ich as nes and yvement e lever, ob once ten fig th four Ee more you il your copy ? wre out your ideas on this practical little lathe. It will handle a wide range of work. In fact, with the attachments shown below it gives you almost a complete shop in your own home or laboratory. It will take work up to 12 inches in length, with a swing of 7 inches. It is furnished with an ad- justable Tee Rest, a Slotted Face Plate, a Saw Arbor and a Drill Chuck of 0 to 4%-inch capac- ity, with a No. 1 Morse Taper Shank. The GOODELL-PRATT COMPANY SLIDE REST NaIse ATTACHMENT NO. IGG , pnieonact Bench Lathe No. 125 For a Variety of Work Toamith Tail Stock has both lever and screw feeds. This useful machine has all of the good features which characterize the Goodell-Pratt line of 1500 different tools. The same skilful workmanship, the same careful selection of materials, the same simplicity, utility and sturdiness are just as evi- dent in this lathe as they are in any other Goodell- Pratt Tool. Let your dealer demonstrate what a serviceable machine this lathe is. And don’t delay writing for a more complete description. Greenfield, Massachusetts, U. S. A. Sea IS aS ANT Ta aa N TN TS ay a TN TS naa a a asa a a ee Greenfield, Mass., U. S.Ag | Sees

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Popular Science Monthly You (an Take Hills on High Without A Knock If you will keep your motor free from carbon. That knocking in your engine—the difficulty you have climbing hills—poor pick- up—lack of power—noisy motor—pre-ignition—in fact 80 per cent of engine trouble is caused by carbon. Clean it out with QOHNSON'S CARBON REMOVER and your engine will run like it did the first 500 miles—quietly and full of ‘“‘pep’’. And your gasoline consumption will drop 12 per cent to 25 per cent. Do It Yourself For 35c—five minutes’ time—and no labor you, yourself, can re- move all carbon deposits. Pour or spray an ounce of Johnson’s Carbon Remover into each cylinder through the petcocks or spark plug open- ings. Let the car stand for half to three-quarters of an hour; then take your car out on the road, drive it 10 or 15 miles at a fairly good rate of speed. You will be surprised at the wonderful improvement. Use It Every 500 Miles If you will use Johnson’s Carbon Remover at regular intervals giving carbon no chance to accumulate, you will automatically eliminate most valve trouble and your engine will always be at its highest efficiency. S. C. JOHNSON & SON, Racine, Wis. Established 1882 Johnson’s Carbon Remover is recommended by many car manufacturers including the Packard and Stude- baker Companies. Handled by all representative dealers OAR, and jobbers. Insist upon yours supplying you. Write > for further information and copy of our booklet on Keep- 8 ing Cars Youtie—ite. free. Made and Guaranteed by ine, Wis. S.C- JOHNSON SON us C. JOHNSON & SON, Dept.P.S.M. 5, Rac ne, Wis Racine, Wisconsin 3 USA: