Popular Science Monthly 1922-03: Vol 100 Iss 3

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R14 199% Popular When Al Jolson Sings by Wireless Beside Ten Thousand Sick Beds . | | ; 5 | | hat Daily Radio Concerts Can You Hear? ( Me 300 Pictures of New Inventions os. inal IMARCH

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Have You Learned to Typewrite Yet? Universal typing is here. People are abandoning the slow, tiring task of long-hand writing. How long are you going to , cling to it, in this world of advancement? Everybody dislikes to receive long-hand letters. And everyone shirks at correspond- ence when it has to be done the old-fashioned, tiring way. So join the progressive throng—get a typewriter NOW. Free * Trial We ship the Oliver for five days’ free trial. Let it sell it- self. Or send it back. 14 Months To Pay Pay for this Oliver while you use it. Only $4 per month and you soon own it. $4950 or $100? Which would you rather pay for a standard typewriter? For 25 years all standard typewrit- ers have been priced At $100 or over and still are—except the Oliver. It is the only standard typewriter selling at half. It is the only standard, $100 typewriter being marketed direct from the factory. Were it not for this simplified sell- ing plan, the price of the Oliver would also be $100 or over. For it is the same fine machine, the finest model we have ever built. Over 900,000 have been sold. We simply sell the identical $100 Oliver direct from the factory, and subtract all the extravagances of com- plicated selling. We have found that it is needless to maintain a high army of salesmen and agents. We have found it unnecessary to sustain a costly chain of branch offices in over 50 cities. The $50.50 you save is the sum that it would cost us to sell the Oliver the roundabout way. Plus a saving made because of the volume of business cre- ated by our plan. Send No Money We let the Oliver sell itself. We ship it to you for free trial. Then you can compare it with other standard typewriters at $100 or over. You become your own salesman. You are the sole judge. No anxious solicitor will urge you. In the privacy of your own office or home you can decide for or against the Oliver. If you want to own it, send us $49.50 cash. Or if you wish to pay for it in installments, send us $3 after the trial period, then $4 per month until $55 is paid. You can readily appreciate that it takes a super-typewriter to sell itself. No test could be severer. Remem- ber, there need be no fluent salesman to urge you. If you decide against the Oliver, ship it back at our expense. We even refund the outgoing transportation charges, so that you do not risk one cent in the test. ‘ Now we ask you, would you rather pay $50.50 additional and not get a finer typewriter? Would you care to support a $100 price for the Oliver, and get nothing tangible in return? Or don’t you agree that our new way of selling is logical? Doesn’t it ap- peal to your common sense? Some of the Famous Users: New York Central Lines, Hart, Schaffner & Marx,.U. S. Steel Corporation, N. Y. Edison Co., National Suit Co.. Morris & Co.—and hundreds of others. 92 Cloak & How to Save The coupon below brings you EITHER a Free Trial Oliver or Fw - ther Information. Check which yo- desire. This is all you have to do to s the $50.50. Without such a plan, yo have to pay $100 or over. But this way you not only so you get the finest typewriter that cou be built by a leading maker. It comes fresh from the factory, our late t and best model, a 25-year developme tt. Check the coupon now and mai! © in. Canadian Price, $79 The OLIVER Typewriter Gmp. 1103 Oliver Typewriter Bldg; Chicago, I" Meta ee eee eee eee ee eee § THE OLIVER TYPEWRITER COMPA? ., : 1103 Oliver Typewriter Bidg., Chicago, Ill. 1 C) Ship me a new Oliver No. 9 Type t writer for five days’ free inspection. » git I keep it I will pay $55 as follows: $3 ” at the end of trial period and then at tk rate of $4 per month. The title to r: main in you until fully paid for. If § make cash settlement at end of trial § period I am to deduct ten per cent anc B remit to you $49.50. "If I decide not to keep it, I will ship it § = at your expense at the end of five ays. a co 4 My shipping point is a... i ' ‘ Cl Do not send a machine until I order & ' it. Mail me your book—‘'The High Cost of Typewriters—The’Reason and the Remedy,”’ your de luxe catalog and fur- ! g ther information. ; ; Name ; Street Address | = Occupation or Business SS SS SS SSS SET SBT eee b | i ‘ 1 ® City State I i all Popular Science Monthly ’ ful the recl phe whe mu thr mit hos ing cas less ind Ne set rel, the he

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March, 1922; 25 Cents a Copy; Vol. 100, No. 3 $3 a Year Popular Science Monthly

—=— Published in New York City at 225 West Thirty-ninth Street

Wounded Veterans Discover New Joys in Wireless Music Radio Outfit Now Becomes Hospital “Nurse” By Armstrong Perry thousands of weary hospital patients these days? It no longer suggests shock and the pain- ful after effects of an operation. Rather, the word brings thoughts of pleasure, recreation, and amusement. For the radio- phone has at last entered the hospital— where, above all places, it belongs—and musical entertainments, broadcasted daily through the ether from dozens of trans- mitting stations, are now being borne into hospital wards and orphan asylums, bring- ing comfort and delight to the lonely in- mates. Radio amateurs, in regions where broad- casts are thick, have long since found wire- less a blessing in hours of illness. It is, indeed, a common practice now, around New York City, for the owner of a receiving set to liven up a sickroom—his own or a relative’s—by hooking up his apparatus to the bed springs, which work wonderfully as an aerial. The patient, donning the head phones, can lie at ease by the hour, D* you know what “ether’’ means to

A Blind Man’s Vision READ, on the next page, the letter addressed to you from a blind wireless amateur. His words will open the eyes of many of us who have been blind to a great blessing which we might confer upon thousands of our afflicted fellows. The radio- phone will bring untold comfort to the inmates of charitable in- stitutions. Will you help organ- _ize a local campaign to install a set in a hospital ?

hearing the gossip and news of the great outside world, and catching in endless variety the lectures, sermons, songs, and instrumental music with which the great

© Keystone SONGS FOR THE LONELY From the radio broadcasting station, the voice of Anna Case, of the Metro- politan Opera, carried cheer through the ether to lonely hospital patients transmitting stations are now filling the ether. From this use of radio in the sickroom at home to the installation of receiving sets in hospitals, has been an inevitable step. Equipped with a loud speaker, one reason- ably priced receiving set can now entertain an entire ward, wiping out forever the gloom and hopelessness of hospital life. Ask the boys in Ward 37, at Fox Hills Hospital, Staten Island, N. Y., for instance. They know! For the “godmothers” of the

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FEW DULL MOMENTS HERE—Wounded veterans of the World War enliven their days in Ward 37, at Fox Hills Hospital,

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22 twenty-five wounded soldiers in this ward of the great government institution on Staten Island gave their “boys” a radio set last Christmas. Since that time, there are few dull moments in the ward. The boys began by re- ceiving an_ elaborate Christmas program from the Newark, N. J., sta- tion. At that time the loud speaker had not been delivered, but the inmates of the ward and their visitors passed the receiver from ear to ear, and improvised a paper horn that made the songs and messages audible to an attentive group. This new interest in life, and the keen pleasure that DITOR or POPULAR SCIENCE MONTHLY: When I lost my eye- The hospital patient, today, can lie at ease and share by wireless in the world’s doings Popular Science Monthly little clip onto his bed spring, picked up an instrument that resembled a telephone receiver, and heard the music of the distant phonograph as dis. tinctly as though the machine were playing beside his bed. The electric currents were changed back, by the radio receiver, into sounds he could enjoy. Hospital authorities who see in this an ex: ample worthy of imita- tion — and _ experience proves that it is—may be interested in a technical fact. The inventor of the system discovered that he could transmit voice and music within the area covered by the hospital without using high frequency currents And we ask _ public spirited readers in every city to start a local cam- sight, some months ago, I suddenly found myself deprived of the majority of pleasures that others enjoy. I realized then how dreary and lonely must be the lives of thousands of inmates of homes for the blind—and, indeed, of all institutions. But to-day, despite my misfortune, I have a brilliant vision for the happiness of these people. A wireless telephone, installed a few weeks ago, has brought me again all the joys that mean most to mankind. I hear daily of the doings of the outside world. I get the news—national, international, political, every kind—even before people who are able to read it in their newspapers. I hear lectures, ser- mons, and concerts. Hours of suffering are turned to cease- less pleasure wherever a radiophone re- ceiving set is at hand. Let me urge you to advocate the installation of receiving sets for the benefit of those confined to homes and charitable institutions. ROSWELL PRESCOTT, Newark, N. J. POPULAR SCIENCE MONTHLY requires no urging in this cause. Founded fifty A Radio Letter from One Reader and a Broadcast Message to All years ago by a famous blind scientist, E. L. Youmans, who contributed greatly to the development of science in America, the magazine feels a special sympathy for the blind. Moreover, POPULAR SCIENCE MONTHLY believes that few marvels of ap- plied science in all the magazine’s 50-year history have brought blessings to mankind exceeding the present promise of the wire- less telephone. We therefore raise the banner now for the extension of radiophone communication by popular demand to its maximum of utility. the radiophone has brought the wounded veterans, is doing as much for their health as careful nursing. In fact, in numerous instances radio is making it possible for the hospital staffs to give their patients something more than medical care. In one of the greatest army hospitals located in Washington, D. C., several hundred patients at a time have been entertained by one pleasant-voiced nurse, who reads magazines into the trans- mitter, tells stories, and sings or says the little cheering things that only a woman can say. At other times during this second experi- ment, a phonograph was started in the central station. It was connected with a radiophone transmitter that changed the sound waves into radio waves. The radio waves swept over and through the hundred or more buildings that constitute the hos- pital. Wherever they encountered metal, they sent electric currents through it. In a white iron bed a soldier snapped a paign for the installation of wireless receiving sets with loud speakers, in deserving institutions. Think what this will mean to the shut-ins in orphanages, in homes for the aged or the blind, and in hospitals. It means that the walls of the institutions are extended to the limits of the earth, as the listeners hear concerts from New York, opera from Chicago, press messages from all over the world, church services from Pittsburgh, news from the local paper, music from many broadcasting stations—more enter- tainment, more points of interest, one is tempted to say, than the average healthy person enjoys. Many newspapers, like the Newark, N. J., Call, the Detroit News, the Seattle Post-Intelligencer, are already sending out wireless broadcasts. In every town a newspaper might go a step further and take up this campaign for radio in hcs- pitals and asylums. Three hundred sub- scriptions of a dcllar each would com-- pletely equip one hospital. Which town will be first? POPULAR SCIENCE MONTHLY stands behind the enterprise, ready to give all possible cooperation and information. HIS typical radio receiving set, such as would serve for entertain- ments in hospitals and other institu- tions, costs less than $250 complete. It consists of head phones (A); loud speaker (B); audion (C); (D); tuner cabinet (E). Here is an itemized statement of the cost of a typical set: short wave tuner, $65; detector and 2 stage amplifier, $65; 5 small ‘‘B”’ batteries, $6; 1 stcr- age battery, $15; loud speaker, $45; head phones, $8; 3 vacuum tubes, $20; 1 plug adapter, $2. Total, $226. With loud speaker and one stage of amplification, such a set will have a phonograph’s range in any room. If conditions are favorable, the set should furnish daily recreation for hospital battery inmates. ) such as are required in ordinary radio work. The radio waves from his apparatus travel through space at the rate of less than 10,000 waves asecond. Passing through the mag- nets of the receiver, they cause vibrations of the diaphragm slowly enough to be heard as sound by the humanear. The bed spring is the “aerial.” The body of the patient, quite unknown to him, serves as 2 “counterpoise,” and makes it unnecessary to have a ground connection. The particular system to be used is not important. One large hospital may broad- cast its own entertainment throughout all the buildings. Another, like Fox Hills, may have an ordinary receivin® set equipped with a loud speaker that permits a roomful of patients to “listen-in” on the regular broadcasts now blanketing the nation. The latter is the simplest and most prom- ising plan. And everybody who knows the ordinary gloominess of life in great institu- tions will realize how completely it will cheer the dreary life of the patients. | N° matter where you live, the chances are that you can hear news and music by wireless. See | on pages 72 and 73 the first radio charts of the United States ever published. fumé¢ doon Brid: thro eter, drag com! was well yard oper and Seey wate crev evel unti fron and by ligh rose lem thr« tub mal mo! stee Du ing, full wit the dis

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ip an hone ic of dis- shine The nged into ‘ities . ex. nita- ence 'y be nical r of ered smit ithin the ising ‘ents ic l- ie) = ~ OF D beer ao — a i. or oS =e ew UM OD March, 19.22 ork. 1vel 000 lag- ons be bed the iS 2 ary not ad- all nay ped ful ilar m- the itu- will How Heroic Young Mechanic Saved Crew of S-48 from Death F pico a grim battle for life 60 feet below the ocean surface, 40 men, near suffocation from deadly chlorine gas fumes, were rescued recently from the submerged submarine S-48 off the Con- necticut coast, through the heroism of a 19-year-old mechanic. At the moment when a 12-hour struggle against rising water and poison gas seemed doomed to failure, Peter F. Dunne, of Bridgeport, Conn., wriggled his way through a torpedo tube 18 inches in diam- eter, and by means of a rope that he dragged with him, made it possible for his comrades to climb to safety. Seas Flood Compartments The accident occurred when the S-48 was on her trial trip. Everything went well until she submerged a few hundred yards from the shore. Then, through an open manhole, the seas suddenly poured and flooded the two after compartments. Seeping into the storage batteries, the salt water liberated clouds of chlorine. Facing almost certain suffocation, the crew worked desperately. They bailed with everything available, even with coffee cups, until they succeeded in preventing the gas from increasing. Then, by discharging oil and dropping tons of pig iron ballast, piece by piece, through a sounding tube, they lightened the ship until the bow gradually rose above water. How to summon aid was the next prob- lem. Young Dunne volunteered to crawl through the long torpedo tube! This steel tube was scarcely wide enough to admit a man’s shoulders. And to make the trip more perilous, its polished length slanted steeply upward. Yet with the odds all against him, Dunne went ahead. Removing his cloth- ing, he wormed his way slowly and pain- fully to the outside of the hull, dragging with him a rope that was to aid the rest of the crew in making the passage—only to discover that the smooth sides of the sub- The perilous journey of 19-year-old Peter F. Dunne to rescue 40 men trapped in the sunken submarine S-48 is de- scribed by the small white figures in the illustration. Dragging a rope with him, Dunne struggled through the narrow torpedo marine offered no projection to which he could attach the rope. But above him on the bow he observed a cleat. Quickly he dove into the icy waters and fought his way through the heavy seas to a point where he could climb to the deck. After fastening his line to the cleat, he tube (1), dove from the tube opening at the bow (2), fought his way through heavy seas (3), and climbing to the deck (4), finally succeeded in attaching a rope to a cleat (5), thus aiding his com- rades to crawl through the tube and signal for aid returned to the inside of the ship, where - he fainted from cold and exposure. But by means of the rope which he had fas- tened, the other’ men of the crew escaped from the gas-filled hull through the tube and lighted flares as a signal to the ship that rescued them. Whirling Wheel on Ballroom Wall Awards Prizes to Dancers O add zest to dancing by mixing orchestra music with a game of chance, a roulette wheel imag is now being used in a London club as a dis- i) tributer of dance prizes. A large dial and pointer The orchestra music ceases as a signal for the dancers to halt and when the spinning hand stops at a number on the dial, the couple standing nearest the corresponding number on the ballroom floor wins the prize on the wall of the ballroom supplies novel amuse- ment for the dancers. Toward the end of a number, the orches- tra leader throws a switch that starts the pointer spinning. The music suddenly stops—a signal for the dancers to halt wherever they may be and wait for the hand to come to rest at some number on the dial. The dance floor is marked in numbered sections, and the couple standing on, or nearest to the number at which the pointer stops, receives a prize. The game is purely one of luck, but as the wheel begins to spin, the dancers maneuver to reach what they believe will be the winning number. D° your shoes pinch your | pocketbook? Read, on pages 56 and 57, how science is improv- ing methods of tanning and so | reducing America’s annual bil- lion dollar shoe bill. Sieh heme ote 2 “es Sar Sareea sa NE so rs kta eit, tee EM

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4 Popular Science Monthly Ml | Tennis Courts Shipped by Crate ' HANKS to a secret method of growing turf in strips of uniform thickness, a gardener named MacDon- ald, of Herpenden, England, is enabled to ship lawn tennis courts in crates to every part of the country. He claims that a tennis court laid by him in the afternoon, will be firm enough to play upon by the next morning, and will be as level as theproverb- ial billiard table. REDWOOD STUMP } 210 FT. HIGH — Cut in strips of Above is the redwood starting its journey. By tautening and slackening guy ropes, a donkey engine moved the tree slowly along on skids Giant Redwood Moved For shipment, the turf is cut into strips and packed on shallow trays. From eight to a dozen of these trays of fresh, green turf are nailed into a crate and sent to their des- tination by express. uniform thickness the turf is laid in shallow trays for shipment This method prevents damage to the turf during transit, and facili- - ti : tates relaying the sod. In making the tennis bu without F elling court, a perfectly flat surface, of course, must be : : prepared as a foundation for the sod. unt ERFORMING a feat said to be without King George expressed much interest in the tel parallel in the logging industry, lum- new method of lawn spreading, it is reported, om bermen of Freshwater, Calif, recently during a recent inspection of MacDonala’s du moved a giant redwood tree, 210 feet high gardens at Harpenden. git and weighing 315 tons, a distance of 20 it feet without lowering it from the vertical bo position. tic The loggers wished to use the tree as a lead pole for pulling in large logs and load- m ing them onto flatcars at the terminus of he the logging road; but it stood 20 feet from . oe st: the right of way, and to move the tracks — pn wet jg plane a to was not practicable. Felling the tree and lead pole for pulling and load- he then raising it again seemed a waste of ing logs at the terminus of the th effort, so the men determined to move the giant without lowering it. First they guyed the trunk of the tree with six 114-inch cables, then sawed it halfway through on one side, and blasted the half stump away below the cut. Skids were placed under the edge of the butt, the rear guys were slacked two feet, the front logging road guys drawn taut, and the tree sawed clear through. Then, by a process of tautening and slackening the guy lines, a powerful donkey engine moved the tree two feet at a time along the skids to the desired position. This section of a lawn tennis court, like other sections, travels by ex- press in trays snugly packed in a shipping crate The Farmer Can O safeguard against an overloaded en- gine and to lessen the risk that some light tractors run of rearing up and turning over, a dynamometer of-recent invention registers on a dial the pull of the farmer’s tractor just as the speedometer records the velocity of a pleasure car. The device consists essentially of a calibrated spring inserted between the load and the drawbar of the tractor. The action of the spring under load is conveyed directly to a dial placed on the dashboard. .-Left—A siakdiinws dial on the dashboard reveals to the driver the actual pull of the tractor at any instant. Above—The action of a calibrated spring under load is con- veyed through a cable to the dial. Right— In the past, the recording mechanism has Now Read Tractor’s Pull as He Rides The dial is supplied with a circular card, revolving by clockwork, that makes a per- manent record of the pull of the tractor throughout the day. Thus if a farmer has a fleet of tractors of the same kind doing the same work, it is a simple matter to com- pare the records and find out what is the best fuel mixture or manner of operation. The effective horsepower can likewise be determined. While the device is continu- ous in operation, it will reveal as readily sometimes been carried by a man the amount of pull at any particular instant. The calibrated spring is strong enough to withstand the rough usage to which it is subjected, and is enclosed in a water and dust proof case. The cable connecting the two parts of the apparatus resembles the regular speedometer cable in outward ap- pearance, but is adapted to the trans- mission of the reciprocating movements of the spring rather than the revolutions of a. wheel. In some states the dynamometer is used in testing the pulling power of tractors be- fore they are sold, as a protection to the prospective purchaser. = Tr tw hh me mA

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hly des- ents cili- nnis t be the ted, ild’s tant. zh to it is and y the ; the 1 ap- rans- its of of 2. used s be- > the March, 1922 25 Giant Trench Drill Digs Subways Now Dummy Cars Test Berlin Motormen Pipet boring machines, designed and completed in Germany etna a tests are employed to select the motormen before the end of the war, and intended for purely military of Berlin. Before the men are entrusted with cars, they must uses, are now being employed in contracting operations by the prove that their visual and muscular reactions are quicker than builders of Berlin’s new subways, now in course of construction. those of the normal man. Standing on practice platforms resem- The machine seems to have been bling the platform of a car, the candi- intended for building mines and coun- dates undergo rigid examinations. termines in ‘‘No Man’s Land,” or for Every conceivable emergency is re- constructing the huge underground : produced, such as breakage, electric dugouts for which the German en- P. — — en : Soa piesa shocks, and accidents. The actions of gineers were famous; — =. store? You see the sales clerk write your name | the novices in meeting such emergen- it appears to be as well a “t ° d © | and address, with the amount of the purchase, on | cles and the time it takes them to boring pipe lines in concrete founda- | 4 charge slip, then pack the slip into a cylindrical | TesPond are carefully recorded. tions. ; : ; box and start it on its way through a pneumatic The tests have revealed that the Power is derived from an — tube to some unknown destination. A minute | ™e” vary greatly in the interval elaps- motor. A winch that winds ina chain | j,+6) the slip returns by the same route, approved | img between visual stimulus and mus- hanging under the borer — @ cOn- | 6 otherwise, to the sales clerk. cular response. Obviously the quicker stant pressure on the bit. : 1% yl What happens in the interval? If youlook be- | ™2” is the better motorman, and tor controls the rate of fee y : hind the scenes in the credit department of the through these tests, the Berlin com- hand wheel regulating the speed o store, you will see long rows of revolving card | Pany has effected a marked lowering the powerful winch. index files. Each file contains hundreds of names | ™ Operating costs. of customers, with an exact, up-to-the-minute record of each customer’s credit. Somewhere among the thousands of names is yours; yet the system of indexing has been so perfected that it takes only a moment for a clerk to locate your name, verify the fact that you have a charge account and determine whether your credit is good for the amount of your pur- chase. If you have lagged in the payment of your bills, that fact is so recorded that the clerk can read the story at a glance. Your Credit at a Glance ¥ yy S 4 ram i ~~ ¥® : * os i 3 . . J Ewing alloway Belgian General Learns to Bat Cpt JACQUES, of the Belgian army, re- ceived a lesson in batting from an expert during his stay in America, when Babe Ruth showed the famous soldier how to “line ’em out.” The Babe demonstrated where to meet the ball, how to stand at the plate, and how to swing. The general proved to be an apt pupil for a man who had never had his hands on a baseball, and is said to have knocked out a couple of cred- itable hits. His lessons in batting, however, were not Water Beats Drum and Hogs Run yw hogs are fright- ened away from the rice fields of Ceylon by a simple yet ingenious device of native invention, consisting of a large piece of hollow bamboo pivoted between two forked sticks, and placed where it will be filled by a small stream of water. A plug or cork is inside the bamboo just below the axis. The upper end, when it fills with water, tips forward, the water spills out, and the bamboo falls back. In so doing, its lower end strikes a large stone, producing a hol- Terminals of the pneumatic tubes through which charge slips travel from store counter to credit department are seen in rear of the revolving files extensive enough to put him low, booming noise that is in the home run class. said to terrify the hogs.

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INCHES operated by electric mo- tors, placed near the railroad tracks on factory sidings, are doing away with the antiquated ‘“‘strong arm”’ or manual methods of moving freight- cars. By expediting the switching, they reduce freight-handling charges. Only seven and one half horsepower is consumed when the machine is used. The gearing of the winch is so designed Winch is Now “Strong Arm” on Factory Siding that this force will put a 4000-pound pull on the rope, and give a rope speed of 37 feet a minute. A capstan of the vertical type adapts the machine for all-round service. This capstan, turned by a worm-gear opera- ting in oil, is self-locking, a feature es- pecially desirable where it is necessary to snub the rope in order to hold the load on down grades. At Last Outdoor Sleepers Can Keep Heads Warm DL jphcketevcg sleeping is likely to be more popular with the use of a newly de- signed electrically heated pad to keep the scalp warm; for—particularly in the damp air and changing temperatures of spring—it is scmetimes difficult to sleep comfortably Wiznout putting the head under the bed- clothes. This, of course, defeats the pur- pose of sleeping outdoors. To fill this need, the new electric pad is shaped for the head and designed so that the temperature never rises enough to in- jure the hair. The connection cord is attached to any electric-light socket. How Costly Is Your Car? | | O you pay a small fortune | each month for fuel, tires, | | and repairs? Read, on pages 74 | and 75, the prize-winning letters | in the contest, “How I Keep Down Car Expenses,”:and dis- cover how other POPULAR SCIENCE MONTHLY readers | hammer down the upkeep of | their automobiles. — “Wade Page Is Negative under Flashlight “ee details from a line drawing are wanted in a hurry, and it is im- possible to take a book containing the drawing from the library or to photograph the page, it is claimed that a rough, emer- gency reproduction can be made with a flashlight and a piece of sensitized photo- graphic print paper. The print paper is slipped under the page to be copied, with the sensitized side against the drawing. Then, by passing a flashlight slowly over - the paper about a dozen times, an image is made that can be developed later. The same results may be obtained when the print paper is placed above the illus- tration. This method is required where printing or another drawing happens to be on the back of the paper. The printed page acts as a negative, since the paper will reflect light to a limited extent while the black ink absorbs the feeble rays altogether. As the page and the sensitized paper are face to face in the second case, the copy obtained will be reversed. Deep Hollows Worn in Old Hammer Handle Hew long will a good a” hammer handle last in the hands of an ex- pert workman? Lau- rence Kaminski, a cooper of Corona, Long Island, owns a handle that he © Ewing Galloway says has been in daily use for 25 years. In addition, the handle serves as conclusive evidence that the much-dehated question, “Do hammer-handles wear?’ must be answered in the affirmative. At the grip, deep hollows have been worn solely by the friction of the. hand; nearly a quarter of an inch of wood has been worn away from each side. The core that remains is smooth and highly polished. It is remarkable testimony to the work- man’s skill that a shaft searcely an inch wide and less than half an inch thick should not have been broken. Auto on Railroad Tracks Hunts Forest Fires OTOR-CARS with flanged wheels are now rivaling airplanes as a means of fire patrol in Western national forests. These cars make regular runs over the rail- road tracks leading through the forest, scouting for blazes started by sparks thrown from locomotives. The auto also serves to bring the fire-fighting crews quickly to a spot where a fire is discovered. Inventors are at work to improve the car, which at present has a tendency to jump the track. The solution of this problem will probably mean an increased use of the flivver by fire-fighters. The ‘“smoke- chasers” extinguished 51 per cent of the 6078 forest fires reported last year before any of them had burned more than one quarter of an acre of forest. Buttons for Germ Food UTTON shavings are the latest source of chemical sugar used in feeding dis- ease germs in the laboratory. Chips from the ivory nut, a product of the wilds of Ecuador, left after making buttons, are treated by an involved process that results in a syrup. This syrup is evaporated and a few grains of white sugar of remarkable qualities are obtained. The sugar is em- ployed also to detect the presence of certain contagious diseases. Popular Science Monthly ,

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March, 1922 ” HE missing link in the chain of human evolution will be discovered some day,” declared an eminent British scientist in 1912, ‘‘in the form of a creature with the brain, voice, and erect stature of mod- ern man—and the brutal face, flat nosed and heavily ridged above the eyes, of a bull ape.” In other words, he predicted, it will be found that man attained his upright posture and full in- tellectual powers long before he lost facial resemblance to his simian forebears. Prophesy Is Fulfilled The discovery thus foreseen a decade ago is now a fact. At the end of a long, tunnel- like cave, 90 feet below ground level on the mining claim of the Rhodesia Broken Hill Develop- ment Company, in northwest Rhodesia, South Africa, native diggers recently uncovered a jawless skull and several large bones of what scientists believe to be a prehistoric ape man that lived at least 50,000 years ago. The cave in which the myster- ious skull lay has become famous, since its discovery several years ago, as the Broken Hill “‘Bone Cave.” Its walls and roof are encrusted with glittering masses of crystals and stalac- tites, while the floor is formed to a depth varying from four to twelve feet, of the partly fossil- ized animal skeletons which must total hundreds of tons in weight. Only in one part of the Does Newly Found Ape Man’s Skull Weld New Link in Our Ancestry? Gorilla-Faced Caveman Had Brain Like Ours

MOST PRIMITIVE REPTILE. EARLY MAMMAL

Where Do We Go from Here? ISCOVERY of a new link in human his- tory—the mysterious ape man of South Africa—stirs up again the unsolved problem of how we really evolved from a pre-monkey type of animal. More than that, it makes us wonder toward what we are evolving now. Some scientists deny that any change in man’s appearance is discernible. But others declare that existing tendencies may make our children’s more remote descendants look like the smallest man pictured here. Man may grow noticeably shorter and darker, with smaller jaws, slighter bones, stronger forearm and larger big toe, losing the little toe and the back molars. Some noted eugenists, believing it possible to breed a physical super- man within a few gener- ations, declare now that unless we evolve con- sciously toward such a glorified race, the human species runs the risk of being completely wiped out like other species before it. Note, by the way, tnat science has yet to find any real trace of a “missing link” between man and lower animals. “tly ‘WW A yr 7772 y val ‘A / E | A ae é —

«

down in the Broken Hill mine in Rho desia, South Africa, the skull Dee of the ape man was discovered. The photograph above shows the skull, in its original position, where it had been for perhaps 50,000 years

PRIMITIVE PRIMATE THE RHODESIAN SKULL

=

MODERN MAN

What story will the next reel tell? A stirring drama of the ages is unfolded in this chron- icle of the evolutionary changes in the form of the head from the elongated, flat reptilian skull with small brain capacity, through the animal types, to the head of modern man ‘ eave, where the walls and the ceiling have been destroyed by the action of water, is the mass of bones cemented together. Else- where the bones form a vast and indescrib- able jumble composed of the remains of large and small mammals, birds, and reptiles. Found in Huge Bone Pile The floor at the end of the tunnel was found to be deeply covered with tons of these remains; and in this great bone pile, one of the diggers found the strange skull, almost perfect, which he took for that of a large ape. The find was sent at once to the office of the mine owners. Later it was possible to recover a large bone of the leg, one of the collar-bones, part of a shoulder blade, portions of the pelvis, and several other fragments not yet identified. An examination of the part of the cave in which the skull and other bones. were found, disclosed evidence that adds a powerfully dramatic element to the discovery. Near where the human skeleton rested, the crushed skull of a large animal, presumably a lion, was found, also a large stone. The combination suggests how man and

Page 10

-——~~ ~ me "<<<" - mae eer ew eer eer eer ee —— = eed INCLINE TO FLOOR OF ———-— = -_——<—-5 = “. OTHERNHUMAN REMAINS wane \ FOUND i.

, a AG FLOOR OF MINE

— i

A In this cut-away view of the Broken Hill mine excavation may be seen the long, tunnel-like ‘‘Bone Cave,’’ at the bottom of which the Rhodesian skull was discovered. The spot where the skull lay is about 60 feet below water level, 90 feet below ground level, and 140 feet below the original hilltop near Dinant, Belgium, in 1887, and since then many other skulls and more or less complete skeletons of that type have been unearthed in different parts of France, Croatia, Moravia, and on the island of Jersey in the English Channel. The Neanderthal race is believed to have lived throughout Europe 25,000 to 100,000 years ago. In 1891 Eugene Dubois found parts of a skull and skeleton near Trinil, a village in lion came to their death. Armed only with a large boulder, this primitive man must have fought a terrific battle against over- whelming odds in the darkness of that African cave many thousand years ago. Both he and the lion succumbed in the struggle and their bodies rested for ages side by side where they had fallen, mute witnesses of the tragedy enacted in the dim past. The presence of hundreds of tons of ani- Popular Science Monthly central Java. They were the remains of an extremely primitive type of man, so near in the stage of evolution to the anthropoid apes, that some scientists were at first in- clined to doubt the kinship between Pithecanthropus erectus, as the Java man js called, and modern man. These remains were found in deposits regarded as con- temporary with those made during the first glacial period of Europe, about 475,000 years ago. Grimaldians Nearer Apes In 1906 the skeletons of a youth and a woman, representing a negroid race, were found in a grotto near Mentone, France, After the name of the grotto, the race to which the owners of the skeletons belonged was called the Grimaldi race. In the structure of their teeth the Grimaldians show a greater resemblance to the anthro- poid apes than the Neanderthal race. In the following year, 1907, the remains of the Heidelberg man were discovered. These represent a much earlier type than the Neanderthal man. The race to which the man belonged presumably lived about 200,000 to 350,000 years ago. In 1912 the remains of the third oldest of the known human types were found in the Thames Valley near Piltdown, Sussex, England. It is believed that the race which the skull represents existed between 100,000 and 150,000 years ago. Between 1852 and the present day skulls and entire skeletons of another widely spread prehistoric human race have been found in France, Spain, Austria, Wales, and Syria. The race, which is of more

mal bones in this African cave presents an interesting problem. Of the origin of the tunnel-like cave the geological formation of the locality offers no explanation. Some geologists believe that the cave is not a work of nature, but was dug out of the comparatively soft rock by prehistoric men many thousand years ago, either for mining purposes or to provide a shelter and pro- tection from the wild animals abounding in that part of Africa at the time. As the age of the human skull found in the cave is estimated to be at least 50,000 years old, and it is highly improb- able that man at that period was sufficient- ly advanced for even the most primitive method of mining, this theory of the origin of the cave seems untenable. The theory be- comes more rational, however, if the opin- ion of Marcellin Boule and a few other paleontologists is accepted. They con- tend that the Rhodesian skull belongs to a much more recent period and probably represents a negroid type which still per- sists in Africa. Evidence of Evolution Ever since Darwin and other scientists of his period laid the foundation for the theory of evolution, believers in this theory have hoped for conclusive evidence con- firming it. The first important find, a skull unearthed at Gibraltar in 1848, greatly stimulated their hope; and when, in 1856, an incomplete skull was found in the Neander valley near Diisseldorf, Germany, these scientists concluded that the so-called Neanderthal man represented an early type in the evolution of man. By comparison it was found that the Gibraltar skull greatly resembled the Neanderthal skull and pre-

sumably belonged to the same period. Two nearly complete skeletons repre- senting the same type were found at Spy,

That our caveman ancestor attained erect gait and a brain equal to our own before his face was refined from the ape- like is a theory apparently substantiated by this reconstruction of the Rhodesian man, facing the gorilla he still resembled

whel still pale high scie of

tiatil and» amp dert’ man veal Hill trac is t} brai yet abo dev cha and Ne tha ee ae a eS ee eS Oe mY

Page 11

of an near Poid t in- ween an is laing con- first ,000 nda were ince, e to aged the ians hro- ains red. han nich out dest 1 in Sex, race een ulls lely een les, ore March, 1922 recent date than the Neanderthal race and probably supplanted it in Europe, was named the Cro-Magnon race. It is believed that the Cro-Magnons came from Asia, where certain of their racial characteristics still survive. They belonged to the later paleolithic age and showed a remarkably high development. In this way, by repeated discoveries, scientists have started to write their record of man’s evolution from the beast. But many pages, even chapters, of this long history are still a blank. On what page shall science inscribe its description of the man of Rhodesia? Brain Case Typically Human For while the Rhodesian skull exhibits a marked general resemblance to the Nean- derthal type, a number of differen- tiating features make it difficult to fix its age and relative evolutionary position. For ex- ample, despite the contrast between Nean- derthal man’s apelike slouch and Rhodesian man’s erect posture, close study has re- vealed that the face of the man of Broken Hill is by far the more apelike of the two. Excellently preserved and showing no trace of mineralization, the Rhodesian skull is typically human in the thickness of the brain case. The brain capacity has not yet been measured exactly, but it is clearly above the lower human limit. Yet facial development is heavy and of decided simian character. The brow ridges are bulging and extend farther laterally than those of Neanderthal man. Clearly, too, the jaw must have been more massive even than that of the Heidelberg man. Dr. A. Smith Woodward, eminent geologist (at left) measuring and studying the Rhodesian skull at the South Kensington Museum, London, England, where the skull is in his charge The development of the dome of the Rhodesian skull presents many puzzling incongruities. Like the skull of the ape man of Java, it has a pronounced crista or ridge extending longitudinally, which indicates a very low type of evolutionary develop- ment. But in size and general contour the Rhodesian skull is much nearer to the mod- ern type of man than that of the Neander- thal man. The race which the Rhodesian represents was evidently long headed. His skull has a maximum length of 210 milli- meters, a width of 145 and a height of 131 29 millimeters. The opening in the base of the skull, through which the spinal cord passes, is located farther forward than in the skulls of the European representatives of the Neanderthal race, and it is this _feature which indicates a perfectly erect posture of its owner. Mouth Adapted to Speech The roof of the mouth is well arched, and the palate of enormous size like that in some skulls of the European Neanderthal type. Thus the mouth was perfectly adapted to speech. The teeth are large, but entirely human. They are much worn and obviously met the teeth of the lower jaw edge to edge. The canines are not en- ’ larged. The second molar is square, the third much reduced in size. All teeth were much affected by decay which also had spread to the tooth sockets. If, despite the apelike features, the char- acteristics of the Rhodesian skull indicate that its owner belonged to a race more ad- vanced than the Neanderthal man, the character of the limb bones found in the Broken Hill cave confirm this evidence with even greater conclusiveness. The tibia is long and slender, of a typically modern form, and might have belonged to a tall, fleet-footed man of the present time. Judged by the clearly distinctive ana- tomical features of his skull and other re- mains, the Rhodesian man must be con- sidered as the representative of a race different from any other prehistoric race known and must be assigned a place in the evolutionary scale somewhere between the Neanderthal type and the Cro-Magnons. Thousand Tons of Rails Test Strength of Concrete Piers ; THOUSAND tons of steel rails were piled upon a concrete pier in Chicago recently, to determine whether piers ex- tending only to a layer of hardpan, and designed for a four-story building, would support the weight of a 16-story structure on the site of the Chicago Union Station. The soil at this point is composed of 65 feet of soft earth over an eight-foot layer of hardpan. Beneath the hardpan a second layer of soft clay and sand is encountered before rock is reached. The tests were conducted to avoid, if possible, the expense of excavating to bedrock, and to find how many additional piers would be required to support the 12 additional stories. Tremendous Weight Applied To conduct the test successfully it was necessary to apply a tremendous weight, and at the same time to install very sensi- tive measuring apparatus to register the exact distance the pier sank as the weight was piled upon it. The top of the concrete column was protected by a steel casting. On this was set a hydraulic jack, through which pressure could be applied. The rails served as a dead weight to bear the upward thrust of the jack, and did not rest upon the head of the pier. The jack used is the largest of its type ever constructed. It will lift 1000 tons when the water pressure on the ram is 6000 pounds to the square inch. To register the effect on the pier, a special inclined draft level, filled with gasoline because of the cold, was set up directly on the concrete head. This gage is so sensitive that it registered the passing of a trolley car over the Adams Street bridge, fully 100 feet away. The test revealed that the pier settled .18 inch under a pressure of 680 tons, and sank an additional .09 inch when the weight was increased to 1000 tons. When pressure was removed, the pier rose .26 inch. The settling, represents the elasticity of the hardpan. N 1000 TONS OF STEEL RAILS ij f . ~ Me ie 1000 TON * HYDRAULIC JACK aa = \| - CONCRETE COLUMNE AND FOOTING 8FT.41IN—— i . TTT] = Se aeeatl Hate, SMALL PIPE TQO.PUMP rag ftHt e +4 Fm How the tremen- dous weight was applied to the con- crete pier and bell- shaped footing through a_ 1000- ton hydraulic jack is described in the cut - away view above eS ae ee BE RE eee

Page 12

Popular Science Monthly | & A SABA. A at i a ee ee ee . * * | errs | nie * ~-nntnhe hee apna ete se ae -— Gshin. Ves! pee ae tem Chicago’s Municipal Parking Place Solves Problems of Congestion and Thievery Buffalo Church Needed More Room, so Workmen Move Stone Wall Thirty Feet phage iealar parking grounds, such as Chicago has opened on - sixteen hours’ working time and without interrupting the N its downtown lake front area, may be a solution of the problems presented by congested streets and by audacious auto bandits that trouble the driver in every large city. The parking feet backward. grounds are operated by the city. The charges are nominal. Only the driver is allowed to enter the parking space, and as he brings in the machine the gate- keeper gives him a card bearing the number of the auto license. This card must be produced be- fore any one is allowed to drive out with that automobile. Sand Castles Made in Fancy Molds IDDIES on the sea- shore may make ornate and highly deco- rated sand castles by the use of a newly devised mold made fromstamped tin, and constructed in four hinged sections. It is locked together, and one corner held tightly while damp sand is packed in firmly from the top. Then the catch is undone, the mold is removed, and_ there stands a castle that will be the envy of the beach. ONE reason milk is almost a perfect food is that it contains a high percentage of calcium salts. Calcium is the chief metallic element of the human body. An adult skeleton contains nearly four pounds of calcium, mostly in the form of phosphate of lime, which is the chief component of bonetissue. schedule of services, the stone wall forming the rear end of the Central Presbyterian Church of Buffalo was recently moved 30 - The wall was moved on rollers resting on heavy timbers care- fully levelled and braced. Screwjacks supplied the motive power. While a stone wall has strength in downward compression, it is Is Giant Mexican Cypress the O'dest Living Thing in the World? EPUTED to be the oldest living thing in the world, a cypress tree standing in the churchyard of the little Mexican town of Santa Maria del Tule has the largest trunk of any known tree. The diameter of the trunk is 50 feet. Twenty-eight people, with arms outstretched and finger tips just touching, can barely reach around the circumference. The diameter exceeds by 14 feet that of the largest of the California redwoods, according to Charles J. Chamberlain, of the University of Chicago. The height, however, is less than that of the sequoias. Judging from a similar cypress tree, five feet in diameter, which was found to have 200 year rings each foot of radius, Mr. Chamberlain estimates the age of the giant cypress at not less than 5000 years. The tree is still thriving, although it was probably of good size when men began to dig the foundations for the pyramids of Egypt. Twenty-eight people, touching finger tips, can barely reach around the trunk of this Mexican cypress. It is believed to be more than 5000 years old not well adapted to withstand the shearing strains that would have resulted had one of the sup- ports been lower than the others. © Keystone Electric Motor Is a Bootblack N_ electric motor transformed into a bootblack can _ polish shoes in less than a min- ute. The operator takes the polish from boxes on top of the machine and smears it on the shoes, then gives the prelim- inary polishing with a motor-driven brush. To finish the job, an attachment consisting of four pieces of heavy felt is placed in an oper- ating handle. As ‘the felt pieces pass over the shoe, they produce a slapping, rubbing action similar to that of a pol- ishing cloth in the hands of an expert bootblack. The motor operates on any electric-lighting cir- cuit. In the outfit is a box that holds all attach- ments for rubbing and brushing. An advan- tage, in addition tospeed, is that only one applica- tion of paste is needed. in tl is | con! flexi life |

Page 13

ithly el dd | nen the f the d 30 care- wer, ngth it is tand ould sup- hers, otor 0a lish nin- akes s on and oes, lim- ha . an ting avy per- ‘the the 2p a tion pol- inds ck. s on cir- is a ach- and yvan- eed, lica- ded. March, 1922 31 New Life-Line Pistol Has Lony Range REATLY _ increased range in a line-throw- ing Very pistol has been attained in a new British model which will shoot life-lines hundreds of feet. The desire of life-savers for a light, portable gun with the accuracy and range of the line-throwing cannon led to the adop- tion of the life-line rifle described in POPULAR SCIENCE MONTHLY for November. The new in- strument is another step in the same direction. It is loaded with a bullet connected with a strong flexible wire, to which the life line is fastened. Shrunken Body Is Two Feet Tall RESERVED _ better than many an Egyp- tian mummy, a shrunken body of an Indian chief who died more than 400 years ago has_ been brought to the United States by Jaun Kratiel, a Peruvian engineer. The mummy is only 25 inches high, for the body was shrunk and preserved by a secret ‘“‘pickling’” proc- ess known only to the South American Indians. Tradition records that this is the mummy of Karruba, a Peruvian chief who led his tribe against the Spaniards in 1535. The beads worn by Sefior Kratiel were found with the shrunken warrior. LA ae a ¥ , oo mee Z Lt “id r Wind Carves Strange Snow Shapes on Roofs During Storm in Swiss Village He” nature, combining snow, rain and wind, will sometimes turn sculptor, modeling strange shapes and designs, was strikingly demonstrated during a recent storm in the little Swiss village of Andermatt. After an unusual series of freezings and thaws, heavy masses of ice, elaborately carved by the wind, hung out like wide eaves from the roofs of houses. A very heavy fall of damp, sticky snow was suc- ceeded by a light rain and thaw. As the snow began to melt, a sudden stiff breeze sprang up that cut the soft surface into twisted and contorted shapes and froze the mass into thick blankets of ice, strong enough to sup- port their own weight. When the pistol is fired, can- vas prevents the flying life- line from cutting the hand So much gasoline is carried up with the natural gas given off by an oil well in Alberta, Canada, that when the tap is removed the minute globules of gasoline form a bluish gray column projecting several inches above the mouth of the pipé. © Ewing Gallowav The body of this Indian Chief was shrunk by a secret ‘‘pickling’’ process Stranded Flying Boat Forecasts Future ‘“‘Grave- yards’’ for Worn-Out Air Liners A BATTERED hydroplane, left on a Pacific Coast beach for the sea and wind to wreck, forecasts the day when airships no longer airworthy will be abandoned in aerial ‘‘bone- yards” as ships are abandoned to-day. The sea has washed away the plane’s launching platform, leaving it stranded high and dry with no slide from which to coast into the ocean. There it rests firmly in the sand while the tides come and go. Unlike ships, planes have little salvage value once the engine and larger fittings are removed. Heavy Jacks and Iron Pipe, Rigged as Stump Puller, Clear Land Quickly |e tgacveakel truck jacks and a simple framework of iron pipe are clearing swampland in Germany at the rate of 30 stumps to each machine a day. The device is particularly well adapted for pulling stumps having a large root spread, and will work better in the moist, soft soil of a marshy area than in hard ground. It has the merit of pulling out the roots as well as the stump, and so preparing the ground for plowing—all in one operation. The machine can handle stumps up to six inches in diameter. The pulling framework is raised by two hand-cranked jacks. gir" . : { h / . "1 : J vaih in| 8 at «14a tm ment! is oe se Will the outworn air liner of the future, like this hydro- plane, find a last resting place on some remote beach? A simple iron-pipe framework to which the stump is attached is raised by heavy hand-operated jacks

Page 14

30 Popular Science Monthly ~ . 2. &..& * 5 AM BS ele ie : > Joe ee ey ear ae ae = eee ae = “~~ Im Chiongn’s Municipal Parking Place Solves Problems of Congestion and Thievery Buffalo Church Needed More Room, so Workmen Move Stone Wall Thirty Feet. ip eigyedleene parking grounds, such as Chicago has opened on - sixteen hours’ working time and without interrupting the 1 its downtown lake front area, may be a solution of the problems presented by congested streets and by audacious auto bandits that trouble the driver in every large city. The parking grounds are operated by the city. The charges are nominal. Only the driver is allowed to enter the parking space, and as he brings in the machine the gate- keeper gives him a card bearing the number of the auto license. This card must be produced be- fore any one is allowed to drive out with that automobile. Sand Castles Made in Fancy Molds IDDIES on the sea- shore may make ornate and highly deco- rated sand castles by the use of a newly devised mold made fromstamped tin, and constructed in four hinged sections. It is locked together, and one corner held tightly while damp sand is packed in firmly from the top. Then the catch is undone, the mold is removed, and_ there stands a castle that will be the envy of the beach. ONE reason milk is almost a perfect food is that it contains a high percentage of calcium salts. Calcium is the chief metallic element of the human body. An adult skeleton contains nearly four pounds of calcium, mostly in the form of phosphate of lime, which is the chief component of bonetissue. feet backward. schedule of services, the stone wall forming the rear end of the Central Presbyterian Church of Buffalo was recently moved 30 The wall was moved on rollers resting on heavy timbers care- fully levelled and braced. Screwjacks supplied the motive power. While a stone wall has strength in downward compression, it is Is Giant Mexican Cypress the O'dest Living Thing in the World? EPUTED to be the oldest living thing in the world, a cypress tree standing in the churchyard of the little Mexican town of Santa Maria del Tule has the largest trunk of any known tree. The diameter of the trunk is 50 feet. Twenty-eight people, with arms outstretched and finger tips just touching, can barely reach around the circumference. The diameter exceeds by 14 feet that of the largest of the California redwoods, according to Charles J. Chamberlain, of the University of Chicago. The height, however, is less than that of the sequoias. Judging from a similar cypress tree, five feet in diameter, which was found to have 200 year rings each foot of radius, Mr. Chamberlain estimates the age of the giant cypress at not less than 5000 years. The tree is still thriving, although it was probably of good size when men began to dig the foundations for the pyramids of Egypt. Twenty-eight people, touching finger tips, can barely reach around the trunk of this Mexican cypress. It ie, believed to be more than 5000 years o not well adapted to withstand the shearing strains that would have resulted had one of the sup- ports been lower than the others. © Keystone Electric Motor Is a Bootblack N_ electric motor transformed into a bootblack can _ polish shoes in less than a min- ute. The operator takes the polish from boxes on top of the machine and smears it on the shoes, then gives the prelim- inary polishing with a motor-driven brush. To finish the job, an attachment consisting of four pieces of heavy felt is placed in an oper- ating handle. As ‘the felt pieces pass over the shoe, they produce a slapping, rubbing action similar to that of a pol- ishing cloth in the hands of an expert bootblack. The motor operates on any electric-lighting cir- cuit. In the outfit is a box that holds all attach- ments for rubbing and brushing. An advan- tage, in addition tospeed, is that only one applica- tion of paste is needed.

Page 15

an Oe, lay = aa ie Pn the the re- er. rth nd ild ip- TS. T= March, 1922 31 New Life-Line Pistol Has Lony Range REATLY _ increased range in a line-throw- ing Very pistol has been attained in a new British model which will shoot life-lines hundreds of feet. The desire of life-savers for a light, portable gun with the accuracy and range of the line-throwing cannon led to the adop- tion of the life-line rifle described in POPULAR SCIENCE MONTHLY for November. The new in- strument is another step in the same direction. It is loaded with a bullet connected with a strong flexible wire, to which the life line is fastened. Shrunken Body Is Two Feet Tall RESERVED _ better than many an Egyp- tian mummy, a shrunken body of an Indian chief who died more than 400 years ago has_ been brought to the United States by Jaun Kratiel, a Peruvian engineer. The mummy is only 25 inches high, for the body was shrunk and preserved by a secret “pickling’” proc- ess known only to the South American Indians. Tradition records that this is the mummy of Karruba, a Peruvian chief who led his tribe against the Spaniards in 1535. The beads worn by Sefior Kratiel were found with the shrunken warrior. ” ** oo q ey a ae de e* z Wind Carves Strange Snow Shapes on Roofs During Storm in Swiss Village He” nature, combining snow, rain and wind, will sometimes turn sculptor, modeling strange shapes and designs, was strikingly demonstrated during a recent storm in the little Swiss village of Andermatt. After an unusual series of freezings and thaws, heavy masses of ice, elaborately carved by the wind, hung out like wide eaves from the roofs of houses. A very heavy fall of damp, sticky snow was suc- ceeded by a light rain and thaw. As the snow began to melt, a sudden stiff breeze sprang up that cut the soft surface into twisted and contorted shapes and froze the mass into thick blankets of ice, strong enough to sup- port their own weight. When the pistol is fired, can- vas prevents the flying life- line from cutting the hand So much gasoline is carried up with the natural gas given off by an oil well in Alberta, Canada, that when the tap is removed the minute globules of gasoline form a bluish gray column projecting several inches above the mouth of the pipe. © Ewing Gallowav The body of this Indian Chief was shrunk by a secret ‘‘pickling’’ process Stranded Flying Boat Forecasts Future ‘“‘Grave- yards”’ for Worn-Out Air Liners A BATTERED hydroplane, left on a Pacific Coast beach for the sea and wind to wreck, forecasts the day when airships no longer airworthy will be abandoned in aerial ‘‘bone- yards” as ships are abandoned to-day. The sea has washed away the plane’s launching platform, leaving it stranded high and dry with no slide from which to coast into the ocean. There it rests firmly in the sand while the tides come and go. Unlike ships, planes have little salvage value once the engine and larger fittings are removed. Heavy Jacks and Iron Pipe, Rigged as Stump Puller, Clear Land Quickly os truck jacks and a simple framework of iron pipe are clearing swampland in Germany at the rate of 30 stumps to each machine a day. The device is particularly well adapted for pulling stumps having a large root spread, and will work better in the moist, soft soil of a marshy area than in hard ground. It has the merit of pulling out the roots as well as the stump, and so preparing the ground for plowing—all in one operation. The machine can handle stumps up to six inches in diameter. The pulling framework is raised by two hand-cranked jacks. YS Tae Will the outworn air liner of the future, like this hydro- plane, find a last resting place on some remote beach? A simple iron-pipe framework to which the stump is attached is raised by heavy hand-operated jacks

Page 16

Hiker Tramps into Jungles on Trip around World Fehon tramping through South Amer- ican jungles where he often was forced to travel from tree to tree above deep swamps, and to rely for food upon his skill with a bow and arrow, W. Kotal arrived recently on the Isthmus of Panama, com- pleting the first quarter of his proposed walking trip around the world. He started from Buenos Aires, Argen- tina, a year ago, and intends to walk north- ward to Alaska, then cross Siberia, Europe, and Africa. How long the trip will take, he does not venture to say. Kotal often averages forty miles a day.

Flashlight Battery Screens Pictures Brightly LASHLIGHT batteries will furnish the illumination in a new magic lantern developed by two moving-picture men. By a new system of lenses and reflectors this comparatively feeble light will produce brilliant pictures seven feet in width, with excellent definition and detail. The lantern is designed to use clips from motion-picture films instead of slides. Since the projection secured with the lan- tern is declared to be nearly equal to that obtained in theaters, millions of pictures taken on the Los Angeles “lots” in the past can be reproduced in the home.

Popular Science Monthly

| | Bicycle Tobogganing Is New Winter Sport |

| pha toboggans are adding new thrills to winter sports in Europe, where a strap-iron frame resembling a bicycle in shape, but equipped with broad iron runners instead of wheels, has made its appearance on the hills. The runners are single, and in tandem, but as the front runner is attached to a set of handle-bars, the coaster can balance himself and steer just as he would upon a bicycle. Because friction between runners and snow has been reduced to the mini- mum, the new sled is speedier than older models. Even in soft snow, the front run- ner packs a path for the rear runner and makes considerable speed possible. A skilful bicyclist can use this sled to “hitch behind” a wagon, attaching the tow- rope to the projecting loop in front of the handle-bars.

Load, and Aim | at $500! ‘THE hunting season for photo- graphs is open! Films are the ammunition. Every locality is a hunting-ground in this contest to win the $50 in cash prizes that POPULAR SCIENCE MONTHLY is offering each month for the best photographs of mechanical and scientific subjects. Join the Hunt for Photographs If you keep your eyes open, you will easily discover, somewhere in your community, a feat of engineer- ing, a clever invention, or a new labor saving machine that will in- terest your fellow readers of Popu- LAR SCIENCE MONTHLY. Load your camera, include one or more human figures in the view, to give scale and human interest, and send the pho- tographs to the Editor. Or, at your workbench you have created some convenience for house, garage, or garden. Photo- graphs of such subjects are equally eligible if a human figure is in- cluded in the view. You Can Bag the Winning Picture Already, photographs that every reader will find interesting are arriv- ing from camera marksmen. First awards and first prize-winning pic- tures will appear in April. Three Prizes Monthly for Ten Months

Ee $25 Seeemtl............ $15 i $10 Keep Your Eyes Open, Your Camera Loaded THEN SHOOT!

Guiding the runners with handle- bars, the coaster rides as on a bicycle

‘Strong Man”’ Is Weakling Compared with Insect EIGHT for weight, the most power- ful professional ‘“‘strong man” is a weakling compared with many common insects. If our legs had the same relative power as those of a flea, for example, we could jump with ease over a church spire 300 feet high. An ant moving a heavy pebble up a little slope of earth is performing a feat equiv- alent to that of a man pulling a railroad train along the track single-handed. Ants have frequently drawn little wagons 1400 times as heavy as themselves. Even the weakest beetle can lift five times its own weight. The rove beetle has

The original ‘‘strong man.’’ The beetle can draw 45 times his weight drawn a cart 45 times its own weight, and has lifted 1800 times its weight in escaping from beneath the cover of a tin can. An ant, caught up by its hind legs with pincers, has been known to lift a small lead ball, into which it has bitten with its man- iples, high into the air. As the ball weighed 800 times as much as the ant, a man with strength in proportion could lift 40 tons.

THAT bright lights attract people was re- cently proved on the New York subway. On some local trains alternate cars had - 25 per cent more light than the others, and these were invariably filled first, some- times being crowded when the next car was almost empty. ’

Marc iia <—— A ei ss THOS

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1g er- 3 a 10n ive we ire tle iv- ad nts 00 ive las 1d th id od th id 1d ar March, 1922 What City Will Floods Wipe Out Next? 33 Dayton’s New Dams Show How It Could Be Saved Vast Catch-Basins, Guarding Ohio Towns, Cost Less than Deluge HOLESALE death and destruction by flood menace hundreds of Ameri- can communities to-day. Yet the inhabitants are apparently heedless of their peril. The great flood catastrophes that have almost wiped out some of our large cities in the past have been alike in one respect— in each case the stricken community thriving cities of Piqua, Dayton, Middle- town, Hamilton, and others, suffered all the agonizing and destructive effects of flood waters such as were more recently experi- enced in Pueblo, Colorado. The cost of the disaster to Dayton was $67,383,574. But to-day the people of the Miami valley are safe for all time to come from a Conduits in the bases of the dams allow no more water to pass than can be carried safely in the riverchannels. The high velocities at which the water emerges are broken up in the hydraulic jump below the exit repetition of such a disaster. Five large earth dams, really artificial hills, forming huge retarding basins, supplemented by many miles of local channel improvements in the principal cities and towns, fully pro- tect the people from the greatest flood nature can produce! The completion of this system of flood- retarding basins and auxiliary channel had taken seemingly adequate pre- cautions for ordinary flood conditions. But when the extreme storm came, ordinary precautions gave way before the full force of nature’s torrents. This very failure to provide against maximum flood is certain to result in dozens of other disasters in the United States in the future unless cities now menaced provide adequate protection. Leading the way in this direction are Dayton and neighboring towns of the fertile Miami valley in southwestern Ohio, which nine years ago were visited by a much more disastrous flood than had ever before been known. The The $67,000,000 Dayton flood cost 400 lives Twelve American Cities Are ‘‘Flood Danger Spots!’’ HE $15,000,000 Pueblo flood, which cost 55 lives, is still fresh in our minds. It is just as like’y as not that this spring may produce a similar disaster on an even larger scale—perhaps in your town. Engi- neers know of at least a dozen im- portant American cities which are under the constant menace of de- struction by floods. The novel system by which Dayton, Ohio, has now insured itself against a repetition of the catastrophe that wiped out over 400 lives in 1913 is described for ‘he first time in pop- ular form in the accompanying article. Read how the Miami va ey system of catch-basins is expected not only to safeguard the val ey towns forever against mundation, but also to in- crease the fertility of the surround- ing farms.—The Editor. improvements marks an era in the ° progress of flood prevention. While the principles involved have been used to a limited extent in earlier works, no similar complete system has ever be- fore been built in any country in the world. The work of construction was carried out during the war. The dams cause the flood waters to back up over the lands above to depths as great as 100 feet, depending on the size of the flood and the particular dam, allowing the carefully designed conduits at their bases to pass only enough water to fill the improved channels below. As the flood passes, the excess waters in the basins are gradually discharged until the basins This $35,000,000 system ofdams makes Dayton forever safe

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Popular Science Monthly Mare stored in the basins below the spillway levels, enough water to cover 1300 square miles one foot deep. To fill the basins to such heights } would require a flood 40 per cent greater in { volume than the one that occurred in March, | 1913. The rainfall investigations carried on by the flood-prevention engineers, which were more thorough and more extensive than any ever before undertaken, showed that such a flood can never occur. The dams contain about 8,500,000 cubic = yards of clay, sand, and gravel, enough to cover 5000 acres of land one foot deep. Their outlet works contain 200,000 cubic yards of concrete. The highest dam is 125 feet above the bottom of the river and ninetenths of a mile long; the lowest is 73 feet above the bed of the river and six tenths of a mile long. At the bottoms of the valleys the dams are from 400 to 800 feet thick, depending on the height. Where they cross the river channels concrete conduits are constructed of such dimensions as to hold back all water in excess of the amount the improved channels below can safely carry. All dams are 25 feet wide at the 1 top, and carry highways from hill | to hill. The river channel im- This view from the top of one of Dayton’s flood-preventing dams, shows how the water backs up on farmlands. Receding later, the water deposits a layer of silt, enriching the soil are again empty. They then re- main empty until the next flood. Thus the so-called retarding Will the Next Flood Disaster basins are essentially dry reservoirs; and the lands within them may be farmed during the intervals be- | | | | | | Strike YOUR Town o he enone Valley below Cairo, io provements cover a total length of 25 miles and involved the excava- tion of 5,000,000 cubie yards of The determination of the maxi- NE flood—the disaster of March, 1913 | material. The er of = at a be opened or closed when the rivers ||. cost Dayton $67,383,574. By expend. |] Pinns Teauires te oa calc — begin to rise; the action is entirely ing only $35,000,000 a second disaster is | of electric traction lines, 22 miles of _ automatic and consequently fool- made impossible. But there are other flood | public highways, 36 miles of tele- aie proof. During low-water periods danger points. Many communities have | phone and telegraph lines, and many fact the rivers flow through the conduits been inundated. Several have made some | costly highway and city bridges. evo without backing up at all. attempts at protection, but as yet none has the How retarding basins operate provided the protection that will safeguard | New Engineering Problems lea’ during floods can be illustrated in them against the greatest imaginable flood. | ste] any bathroom. Simply turn on the The following points are declared by en- | The design and construction. of cau water in the bathtub, leaving the gineers to sn emeetents chek danger spots: | the works involved _ engineering bel drain open. Pat soa ipa ad | problems never before investigated. tw into the tub faster than it can flow | out of the open drain and conse- quently will slowly fill the tub. . Lower valley of the Sacramento River, mum possible flood, the design of the concrete conduits under the z When its level reaches the level of 3. Pigg ge ny and Mononga- dams, the hydraulic design of the I the overflow, water will begin to hela rivers, Pa. basins, the problem of dissipating c flow out of that opening, and as 4. Whetstone River basin, Columbus, the energy of the rapidly moving I soon as the total discharge of the hio. water as it emerges from the con- " drain and the overflow becomes 5. Junction of Missouri and Kansas duits, the method of building the F | equal to the discharge of the faucet rivers, Mo. f dams, were all engineering features i the water in the tub will stop rising. 6. Headwaters of Los Angeles River. requiring special investigation or 0 3. foes ~ adameer aaa valley. experimentation. So unusual have ee A Gigantic Bathtub ; e been the engineering studies and These are the critical points, but there the construction methods employed Si The surface will then remain are others. A prominent flood engineer de- that the work has been visited by stationary until the opted is peri clares ihat unless a certain upstate New eminent engineers from all parts cf re when, of course, it will begin to fall ° é a ace - the world. and the tub will empty. apes a i : rg ae “4 be visited Probably the most difficult prob- ee The bathtub corresponds to the y y lem encountered in the design of the = retarding basin; the stream from Will the next disaster be in your town? dams was that of breaking up the Me the open faucet to the river flowing terrific force of the water as it into the basin; the water going out comes out of the conduits. During a. of the drain to the flow through the moderate floods the water emerges h conduits under the dams; and the water passing : t out of the overflow to the water flowing over the spillways. i However, in the Miami valley basins the water will never reach the spillway levels; that is, the : faucet will be turned off before the overflow comes into use. The basins are so large and the ; conduits so proportioned that the maximum flood Nature can produce will not be enough to i raise the water to the spillway levels! The total cost of the works, paid entirely by the property owners benefitted, was about $35,000,000. The improvements, extending from the Lockington dam on the north, to Hamilton on the south, benefit a territory over 100 miles long, extending southwestward to the junction of the Miami River with the Ohio, and involving parts of nine counties. Thirty-six thousand acres of flat bottomlands lie above the dams, ready to be flooded at any time. Nearly 850,000 acre-feet of water can be ' eS COS By the hydraulic fill method of dam-building, a mixture of sand, gravel, clay, and water is deposited at the edge of theembankment. The roma and gravel settle, while the clay goes to the pool in the center, forming an impervious core 7

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o) a a ma CD ™’ § Bh WM WIC eh I mh I . = =~ March, 1922 TOP OF DAM 25 FT. WIDE TOP OF SPILLWAY—__ ( ae fq. OF we tee X : S To fill the retarding basin to the top of this concrete spill- peas 7 yond ” only 20 “* aon oe on ydraulic- eart ams are built to form retarding basins is described by the cross-section diagram above way would require a flood at a speed of about 25 miles an hour. If it were allowed to enter the natural channels immediately below at such a velocity, it would erode them and endanger the dam. After a year’s experimentation, a satis- factory solution of the problem was evolved, based on a phenomenon known as the “hydraulic jump.” The water, as it leaves the conduits, flows down a series of steps into a wall of water, called the jump, caused by two concrete weirs immediately below and only about 40 feet apart. Be- tween the jump and the lower weir the 40 per cent greater than that of March, 1913. And research has revealed that the greatest speed of the water is broken up so thor- oughly by the obstructions that it flows away at a very normal velocity, the entire operation taking place in a length of only about 100 feet. Five years were spent in making the necessary surveys, studying different plans of flood protection, designing the dams, and overcoming the legal obstacles. Four years were consumed in actually building the works. Thus nine years elapsed between the beginning and completion. The dams were built by the hydraulic- Meter Times Phone Calls ONG distance telephone calls sometimes end in arguments over the time for which the subscriber should be charged. To eliminate such discussions the French Postal Service has installed meters in public phone booths to give the subscriber fair warning when his period is about to end, and to time the conversation mechanically. The meter is a stopwatch arranged to light electric signals in the telephone booth. When the connection is made, the central operator plugs one of the jacks into a con- nection on the timer, which cannot start until the line is clear and ready for use. Two minutes and a half later, the hand of the watch makes a con- nection for two lamps hooked up in series, one of which lights in the central officeand the other over the public telephone. This light warns the speaker that his time is nearly up. Exactly at the third minute, the lamp is ex- tinguished. If the sub- scriber continues to talk, he must pay for an additional period. The — telephonometer makes a second revolution, and 30 seconds before the end of the second period gives the same warning as before. Thus far, the meters have been installed When the time is nearly up, a stopwatch (below) lights an electric warning signal in the telephone booth (above) only in public telephone booths. The in- strument is said to be of service to the public, since it enables the subscriber to gage his time automatically. fill method, one of the greatest engineering developments of recent years. In such construction the material to build the dam is washed into place by running water from hillsides above, or is pumped into place through long pipe lines by huge dredge pumps. The mixture of clay, sand, and gravel with water is deposited at the edges of the embankment, which are kept higher than the center; and the water, draining toward the center, deposits first the gravel, then the sand, and then the clay, thus giving the ideal structure for a dam—porous outer portions with an impervious core. When the mixture is pumped, the ma- terial may be delivered’to the pumps by cars or by running water from higher eleva- tions. All of the. different methods known were used in the Miami Conservancy operations, some of them being developed to stages much nearer perfection than ever before attained. Flood protection is nct the only benefit derived from the construction of the dams. During each flood the backwater within the basins deposits a thin layer of silt that increases the fertility of the soil. It is ex- pected that due to this gradual deposition the fields will some day become equal in fertility to the lands along the Nile, where continual cropping is practised without the use of manure or fertilizer and with no detrimental effect on the soil. A Dam Built of Marble! THE largest artificial lake in Asia, formed by a magnificent dam built in India by coolie and elephant labor nearly 280 years ago, will be described in the next issue. Traveling by elephant into a region rarely penetrated by Occidentals, Eleanor Maddock, wife of an American physician, who writes the article for POPULAR SCIENCE MONTHLY readers, discovered interesting details of the primitive methods by which this marvel of beauty among reclamation projects was con- structed. You will enjoy comparing, next month, the pictures of the Jaisamand dam with those of present day engineering feats, such as are de- scribed in the foregoing article.

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a al Steam Heating Unit for Shop Is Also a Ventilating Plant POWERFUL blower, placed beneath compact steam-radiator coils forms a compact unit that both heats and ventil- ates large factory floors. The steam coils are shaped like those in instantaneous gas- heaters affording a large radiating surface. A novel improvement has been effected by the introduction of a header pipe con- nected with all the coils. A valve placed on each coil makes it easy to regulate the amount of heat produced by the unit. A belt or electric-driven fan draws the cold air from the floor, and forces it through the coil. At the top of the unit four venti- lating tubessend the currents of warmed air to different parts of the shop. This results in a constant circulation of air without pipes or ducts that might interfere with belting or the shop machinery. A pipe leading outdoors converts the unit into a ventilator when required. Proves that Georgia Is Good Trapping Country Animal skins in demand throughout the world are on display at this hunting camp A SMALL part of the season’s fur catch of J. L. Glaze, of Vidalia, Georgia, is shown in the above picture. The square ring-tailed furs are raccoon, which are of great commercial value in the United States, while the smaller skins are opossum, for which there is a brisk demand in Europe. The various traps and decoys used are shown between the skins in the illustration. Topsy-Turvy House Advertises Real-Estate Office pened pa that a grotesque building would have decided advertising value, a California real-estate company recently built its field office with a twisted, sagging roof, and doors and windows set out of plumb. The idea is said to have come from the “dream villages’’ and Alice-in- Wonderland The owner built his odd shaped office to attract attention to his business towns that have been a feature of amuse- ment parks for many years. As far as is known, this is the first time the idea has been applied in the business world. | | If there are questions in general | } ° . | | science that have been puzzling you, | | send them to the Editor. On page 62 | | you will find the rules and regula- | tions governing this service together with a number of questions that | have been submitted by readers Popular Science Monthly Oxyacetylene Cutting Torch Works Automatically © pine teeneriie cutting. can now be done automatically, even on irregular shapes, with a new machine in which the cutting torch is attached to an arm re- sembling a pantograph, guided by a thin wooden template. The accuracy of the device is such that the flame may be used to cut gear-teeth. As a matter of fact, it is said that the cut may be controlled to a few thousandths of an inch, so that the work turned out is ready for finishing on the lathe. Naturally, the shop economies possible with such an invention are remarkable. No highly skilled labor is required, and it is claimed that 15 inches of half-inch plate can be cut accurately in any shape in less than one minute at a cost of less than one cent for oxygen. The cutting flame is enclosed in a fireproof metal box. Hot nitrogen gas of high purity has been discovered in one of the lead-silver mines of Utah. It is believed by the Bureau of Mines that the automatic extraction of the oxygen in the air through the oxidation of sulphides was the cause of the phenomenon. The gas had a temperature of 175° F., although the air three feet below registered only 135°. Several samples of the gas averaged 9914 per cent pure nitrogen. Subway Road Carries Coal from Canal to Factories 1 1 halen A spoiling the appearance of a residential street or depreciating property values in the neighborhood, coal- loading machinery has been installed on the canal at Neukélln, Germany. The coal is picked up from barges in clam- shell buckets dropped from the projecting An undesaveuad road between the tactory district and the coal on the canal bank is used to cart coal and ashes in Neukoliln, Germany beam, and falls through the tower into underground cars. These carry the coal to the stoking-rooms of large factories in the vicinity, and on the return trip the ashes are carried back to the canal and loaded into the barges that brought up the coal. On the right is a battery of old-fashioned coal-loaders, which are being replaced by the new system as rapidly as possible. ket tower e han two clai litt!

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ORDO S&S Sue” OD Ee dl —_— ww we We March, 1922 One Hand Watch Tells the Time Accurately E _ shall have to learn to. tell time in a new way, if a one- hand watch, re- cently patented comes into gen- eral use. The watch has no minute hand. Instead, a spe- cial dial makes it possible to read the min- utes accurately from the posi- tion of the hour A new type of clock has an hour hand and a special dial hand. Children can learn to tell the time two years earlier with this watch, it is claimed. As there is only one hand, very little calculation is required. How Tough Is the Skin on the Surface of Water? This sensitive scale measures the minute force of surface tension on water or other liquid VERY one has floated a needle on the surface of a glass of water, or watched a bit of camphor skim from side to side of the glass. These simple experiments were to prove the existence of surface tension. Now comes A. W. Fahrenwald with an instrument that will measure the force of surface tension on any liquid and tell us just how tough the “‘skin’”’ of water is. The liquid in the watch-glass is raised until its surface comes into contact with two knife edges ground on the bottom of the triangular bar. The glass is then lowered, and a plane film is drawn out. Tension in this film rotates the indicator, which is a.light wire fastened in a two and a half inch cork wheel. The forces meas- ured are so slight that all parts of the apparatus are made as light as possible. In measuring the tension of water, the pointer first swings to the 80-dyne gradua- tion as the upper surface of the horizontal bar breaks through the surface film. As the liquid is lowered farther, the film is drawn from the lower knife edge, and the pointer rises to 92.85 dynes, which is the correct reading. 37 All-Weather Bus Comfortable the Year Round For summer travel the windows and frames slide out of the way, leaving the sides of the bus wide open a twenty-five passengers, an all-steel bus has been designed for com- fort in all weathers. In winter the body is completely enclosed and warmed by the exhaust pipe. In summer, the windows swing out of the way. The sides are open, and the view unobstructed; not even the frames in which the windows slide are left in place. The front and rear windows on each side are hinged, and when not in use In winter the tightly closed bus is heated by gases from the exhaust pipe ean be concealed in the panels. New Street-Cleaning Buggy Provides Own Shovel STREET-CLEANER’S cart that fills itself enables the White Wings of San Francisco to leave their shovels at home. Pivoted on the axle is a combined shovel and collection bin, from which ex- tends a long handle for the operator. When in use, the bin rests on the ground, and the street refuse is swept.into it. When the box is full, the operator swings it up- A shovel shaped pan swung from the buggy axle takes the place of the usual scoop ward on its pivot and dumps the sweepings. The cart is pushed or pulled by the handle. The weight and braking action of the swinging box as it rests on the ground is sufficient to hold the cart steady. COMPRESSED air was used to fish an electric wire through a long conduit in Los Angeles, California, where a distance of 450 feet between outlets made the usual methods impractical. A pneumatic fishing machine was used with a special cord of heavy fish- line. An incidental advantage was that, during the operation, all dirt and foreign matter in the pipe was blown out by the air. Heavy Pressure Used to True Up Phonographs ORCEFUL measures are used in one phonograph factory in order that the cabinets may stand solidly on their feet —for it is known that the slightest loose- ness in the frame seriously injures the tone of the instrument. In this particular operation, a pressure of about five thousand pounds is applied to the top of the cabinet with a hand screw. The steel floor of the pressure-frame is Set screws exerting a tremendous pressure are used to level up phono- graph cabinets very carefully levelled, so that if the cabi- net has not been made square and true in every dimension, the fault is corrected when the pressure is applied. Two of the cabinets are pressed in the frame at one time.

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38 Popular Science M onthly Which of These Time-Savers Do You Need? | Gaskets and washers of leather, rubber, metal, or other material are quickly and accurately cut with the aid of this compact little rotary cutter With a spindle speed of only 1200 revolutions a minute, the riveting ma- chine shown above will strike more than 14,000 blows without severe strain on the mechanism MAGAZINE Piston-rings are fed automatic- ally from a magazine to the rotating worktable of this grind- ing machine. After being ground they drop to the _ receiving spindle Iron plates, five eighths inch thick, may be cut easily with this machine, which has rotating cutters working under tremendous pressure and constantly lubricated. -The machinist guides the metal by hand wae! \ separABle BLADE AN D_SHANK™ As the shank of a reamer will outlast many blades, the idea of making the shank part separable from the blade part by a screw joint will result in economy dng LOCKING LUG AND PINi In this new face- milling cutter the teeth are positively locked so there is no chance of their slipping or becom- ing loose under strain. They may be adjusted or re- placed Rollers instead of teeth in the worm of the new auto- mobile driving gear pictured above bring the efficiency of the drive to 97 per cent i Springs automatically hold the legs of this new type of calipers in contact with the object to be measured LEVER ARM” MOISTURE SCALE IN GRAINS This recently invented multiphase fuse is renew- able and will protect multiphase motors and circuits on starting and running loads: from burn- ing out when a fuse blows Every carpenter’s bench needs a bench-stop against which boards or strips may be braced during planing operations. The stop shown above, when not in use, is set flush with the bench-top. It may be set at different ‘heights HEAT FOR For measuring the percentage of moisture in wool, the scale pictured above has been in- vented. The percentage is regis- tered directly on the calibrated dial, requiring no mathematical calculations pe p p b f mi’, at we a ee ee eee

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March, 1922 Here’s the House that “Jacks” Built! Complete Walls of New Concrete Homes Now Raised by Screw-Jacks in Half a Day GASOLINE engine tugs; giant screw-jacks slowly stretch their necks, and up goes the entire side of a building—all complete, with windows, cornices, moldings, and decorations! At noontime, four solid concrete slabs lie flat on a building-lot. At evening, as if by magic, the four walls of ‘“‘the house that jacks built” stand in place. And so has come about a revolution in home-building methods that may make concrete houses as cheap as frame construction. The erection of a concrete building in one afternoon is accom- plished, not by a magician, but by a carefully planned, scientific system of construction, invented by Col. Robert H. Aiken, of Washington, D. C., and executed by Snowden Ashford and Carroll Beale of the same city. The work is completed without the use of forms and scaffolding, and without “‘pouring” the concrete in the customary way. This is how it is done: The basement floor is laid in the usual manner, and finished 39 ee ae > RSTn INI NTN ti LZ smooth to a level. The hoisting-jacks and trusslike girders Here is the front wall of a house jacked to a vertical posi- are alined in front of this floor, and upon the girders loose planks are laid transversely, until a platform the size of a side wall has been built. All the window- and door- frames are laid on the platform, and con- crete is poured around them. At the same time all the details of the completed wall! are cast in place, either by nailing an insert or print-block to the ‘platform, or by carving a design into it, according to whether the ornament is to project from the wall or not. The four walls of a concrete house of ordinary size can be molded in about two hours. The concrete on the platform for each wall is then allowed to set for three days, until it becomes thor- oughly dry and hard. Walls Rise without a Break Next comes the hoisting of the walls. By means of a common driving-shaft, all the jacks are connected with a low-power gasoline engine, and as this is started the platform and wall, pivoting on one edge, rise slowly into place without any risk of breaking during the ascent or of rising past the vertical and falling in the other direc- tion. Such mishaps are made impossible A whole row of houses is erected by a by the careful designing of the jacks and single crew in a day. Above—One guides. a is WP, while ao og in on 4 _Telescopic screw-jacks, set from six to Si We cee be eee eight feet apart with the toe of each jack corners, the walls become dwellings The 50-foot wall of a factory, including windows, goes up without a crack. The photograph gives an idea of the immense power of the erecting system tion. Note how the five telescopic screw-jacks are geared to acommon shaft, driven by a small gasoline engine resting on the footing of the foundation, are raised by screws turned by bevel gears from the common shaft, so that one jack never extends faster than its neighbor. While the planks of the platform might keep the wall from cracking if this should happen, the inventor relies upon purely mechanical methods for controlling the rate of ascent. Exterior Is Waterproofed To reduce the weight, and to prevent moisture from condensing on the inside of the walls of the completed house, a con- crete mixed with coke braize and cinder has been adopted. Several years of experience have proved that this material has ample strength, yet is porous enough so that nails can be driven into the inner side. The outer section is made waterproof with a two-inch layer of concrete. Once erected, the walls are united at the corners by casting pillars of concrete at the joints. This is easily done, because in making the wall, the iron reenforcing-rods are allowed to project about 30 diameters. As they interlace when the walls come into position, it is not difficult to pour the con- crete corners around the iron reenforcing- rods, The walls are usually laid out in the interior of the building before raising, but they may be placed outside if space per- mits and if it is desirable to raise all four walls at once. With this method it is possible to raise an entire factory in a-day, or to build an entire row of houses at one time. In the latter case, three or more fronts are raised one after another during one working-day, with one crew using the same equipment. In addition, the method makes it possible to build an elaborate concrete house with nothing but common labor. Only one plasterer is required for finishing the cor- ners. The elimination of form work and every sort of elaborate finishing is expected to make concrete-walled houses cheap enough to compete not only with brick, but even with wooden frame construction. OR further information con- F cerning the houses described in this article, or for answers to other questions in general science, write to the Information Editor (see page 62).

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40 The S-51 is a double-hulled sub- marine, embodying all the latest improvements Pigeons Herald Plunge of New Submarine LOUDS of carrier pigeons rose from the decks of the United States submarine S-51 as she was launched into the waters of Long Island Sound, at Bridgeport, Conn. The pigeons circled twice over the hull as it floated out into the sound; then they started off in all directions to broadcast the news that the launching had been successful. The S-51 embodies the improve- ments in submarine construction learned during the world war. In cruising radius, armament, signaling apparatus, and arrangements for the comfort of the crew, she marks a great advance over the underwater craft of three yearsago. Asister ship recently made an As the submarine hit the water, hundreds of pigedéns rose from her decks:and flew in every direction to carry the news of the success- ful launching Popular Science Monthly Rotary Machine Casts Concrete Shapes —— concrete shapes can be successfully cast on a new centrifugal machine that will turn out four blocks every 60 seconds. A revolving table carries hollow molds into which concrete is fed by centrifugal action through a central orifice. Excess water is squeezed out by centrifugal force during the spinning. The amount of water in the finished product may be governed by regu- lating the speed of rotation. Hollow articles may be cast by placing cores in the mold. Similarly, the blocks may INTERCHANGEABLE RADIAL MOLDS WITH CORES TRACK AND- ROLLERS ROTATABLE CASING be reenforced by wires stretched across the interior. In both cases the concrete tends to pack solidly about the obstruction. Filling the molds is completed in from 30 to 60 seconds. The mold is then opened along its bottom, and the shape falls on an endless belt, which carries it to the drying stacks. When the shape is cast, there is usually a finlike projection from the mold into the central chamber. A cutter sliding up and down the walls of the feed-chamber removes this from the completed shape. You Can Rival Mahomet’s Coffin Mystery 8600-mile cruise from Portsmouth, N. H., Wr the simplest of apparatus you placed between two charged rods—and it to Honolulu. These long voyages are can perform an experiment appar- willremain there, hanging in the air without possible because of the large size of the ently defying the law of gravity—a seeming any visible support. later submarines. miracle as mysterious as the legend of If a brass conducting-rod with a brass The length of the new vessel is 240 feet Mahomet’s coffin. A over all; beam, 21 feet 6 inches, and draft, 13 feet in normal surface condition. The displacement is 993 tons. The vessel is of the double-hulled Lake type for one half the length amidships; while the forward and after portions are of the well known single-hull type. Safe at 200-Foot Depth The S-51 can submerge safely to a depth of 200 feet, and is driven on the surface by two Diesel engines, each of 950-brake horsepower. Storage bat- teries and electric motors drive the ship when submerged. There are three peri- scopes, for the reason that during the war it was found that periscopes were frequently shot away. One periscope with its eyepiece in the conning-tower is carried on an elevator platform so that the observer, by moving up and down inside the hull, can keep the end of the periscope just a foot or two above the surface. The other two peri- scopes lead to the control room. Improved radio apparatus is in- stalled for use both on the surface and when submerged. Submarine coils are provided so that radio messages from the fleet can be received when the submarine is under water. A 14-foot lifeboat and a 4-inch gun are carried. ball on the end is continuously strip of gold leaf may be 4 According to an old Oriental legend, Mahomet’s coffin was suspended midair by a huge magnet in een mes charged with positive electricity, ELECTRODE and a pointed conductor placed nanan a few inches below it or held in the hand, a piece of aluminum or gold leaf placed between them will remain balanced in midair as long as the rods remain charged. ean Negative electricity exists in LEAF very small particles called elec- trons, which are free to move under the action of electromag- netic forces. Particles of positive electricity are not free to move. Adding electrons toan uncharged POINT body gives it a negative charge, while removing electrons from an uncharged body leaves it with a positive charge. The positive charge in the upper electrode draws electrons to the pointed top of the strip of gold leaf, leaving the lower end positively charged. This charge in turn draws electrons from the pointed conductor below. If the strip moves upward the stronger attraction causes it to lose more elec- trons from its point while it gains less from below. Hence the force on the strip weakens and it settles back into a position of equilibrium. If examined in the dark, the gold leaf is seen to emit sparks, showing a continual loss of electricity. Sd ee ee ae ee ee ee ee al Oe i i ie li ll le

Page 25

March, 1922

What Is Your Question? Scores of POPULAR SCIENCE _ MONTHLY readers are receiving use- | ful advice daily from the Information Department (see page 62). Every variety of practical problem is promptly answered. Why not put your question up to the Information Editor ?

The Mirror Is Full of Cheer — Just Unscrew the Handle O one can fail to be cheerful after a glance in this mirror. For—you will promise to keep the secret—its handle will unscrew, and between the glass and the silver case there is a hollow space big enough to hold three fingers of comfort. The mirror has been manufactured so that awoman may havea convenient place to keep perfume or smelling salts.

The handle unscrews, and the inside of the mirror contains perfume 41 Here’s a Trailer that Helps the Roads!

OR a 20-ton truck to improve every gravel road it passes over sounds like an engineering paradox; yet such an advan- tage is claimed for a freak four-wheeled semi-trailer recently constructed by a Detroit firm to refute the argument that the motor truck is destroying the nation’s highways. The use of four wheels in line gives a total tire or load-bearing surface of 48 inches and allows a load disposition of about 800 pounds to the square inch. As attached to a truck, the load is dis- tributed over six wheels, more than eight feet between centers, so that the trailer When the novel trailer is attached to a truck, as shown above, the load is distributed over six wheels. At the left may be seen the shock absorb- ing springs for each wheel may be taken over any modern bridge without producing undue stresses. The four-wheel principle has proved so effec- tive in practice that the manufacturer is now guaranteeing his product for a load of 40 tons. Because of the unusual spring mount- ing, the trailer is not seriously affected by holes in the pavement. Independent double acting springs are provided for each wheel. If one of the wheels drops into a hole, the load instead of falling two or three inches and bringing up with a heavy jar, is shifted to the other three wheels, thus preventing sudden strain on the springs. On soft roads the broad tires, it is claimed, consolidate the surface without breaking down the subgrade. The truck was designed especially for hauling heavy electrical machinery, flywheels, and struc- tural steel, all of which are constantly in- creasing in size and weight.

Automatic Coupling Will Save Time, Money, and Lives A SUCCESSFUL registering device in the shape of a pyramid is now solving the problem of 100 per cent automatic coupling on railroad cars of several Ameri- can lines. In other words, tion, the device has a range of seven inches. Before coupling, the coil-springs hold the connecting plates two inches farther from the car than the car-coupling proper. When the cars come together, the shock com- presses both springs, and as the coupling heads lock, the connecting plates remain under pressure. This pressure would

air, steam, and signal pipes, as well as the cars them- selves, are coupled solely by impact. These connections, set in the faces of the new-type coupling mechanism, are held tightly together by the pressure of 300-pound coil springs. No longer need the brakemen crawl be- - tween the cars to link the various hose ends. Thus, the universal use of the

wear out rubber pipe gas- kets, so ic is borne by four metal contact points on the faces of the connecting plates. The fluid pressure of steam and air is relied upon to keep the pipe-lines from leaking. To prevent excessive pressure in the steam lines from forcing the connector

device will undoubtedly greatly reduce the number of coupling acci- dents, in addition to saving time. On each car the automatic hose-connecting plate, placed below the familiar automatic car coupler, is divided into two symmetrical sections, one occupied by a pyramid, and the other by a hollow frame which fits snugly over the base of the pyramid on the opposing plate of another car. Thus the air, steam, and signal lines of two cars will register ex- actly, provided the pyramid point of one plate engages anywhere inside the frame of the other; for the pressure with which the cars come together will force the plates into the proper position. To assure this connec- plates apart, the latter are cast with slight raises in the frames, resembling lips.

AUTOMAT! -CONNECTOR PLATE \ PYRAMID

STEAM LINE LON F

Air, steam and : ep Ss, as <n as the cars, are = by impact These lips lock when steam pressure starts to separate the hose lips of the steam connection, but will disengage instantly when the pressure is re- duced to the normal pressure of the springs. That the device is practical and economical was proved by tests on many railroads. The air leakage is slight. In the case of a 37-car train, the highest loss was seven pounds in five minutes. The greatest econ- omy is in time saved in coupling. Brakemen need not crawl under the train in uncoupling, as the coupling heads are released in the familiar way by an iron lever from the outside of the car, and the connec- tion plates unlock automatically when the cars are pulled apart. *

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Popular Science Monthly Do You Know How Germs Make Food for Your Table? Ten Everyday Wwenters that Unlock the Secrets of Science back of our daily lives. F-VERY month POPULAR SCIENCE MONTHLY pub- lishes 10 common questions about the scientific facts Find out from the answers on this page how well you really understand the funda- mentals of science that everybody wants to know. 1. Are bacteria always harmful? Are they ever useful? 2. Just how does the ‘‘weather man’”’ predict the weather? 3. Why is yeast put into bread dough? Why is dough kneaded? 4. Why do we get sea breezes by day and land breezes by night? 5. Why is it better to breathe through your nose? 6. What is a calory? How many does a baseball player need a day? How many does a bookkeeper need? 7. What causes lightning and thunder? | §. What makes the heat inside of an electric iron? door is opened? 9. Why does a blue flame appear on a coal fire when the stove | 10. Why does the air feel more invigorating on a clear day than on a damp day, even though both days are cool? Read the Answers Below Five Minutes a Day Will Make You Master of These A-B-C’s of Science Some Bacteria Are Useful Not all forms of bacteria are causes of ¢ disease. There are certain bacteria which produce changes in dead organic matter, such as rotting trees, leaves and bodies of animals, and these changes make the elements of the decaying bodies again available as food for plants. Certain bac- teria, too, make the nitrogen of the air available for growing crops. Still others, which feed on the dead remains of plants or animals in the sea, are in turn eaten by larger, but still minute, forms of life. These are then eaten by still larger animals, and so on, until we get to forms of life that we can use as food ourselves; such as shrimps, fish and oysters. How the ‘‘Weather Man’’ Does It ? At 8 A. M. and 8 P. M. of every day in * the year, 200 trained observers at 200 different stations scattered throughout the United States, Canada and Mexico, tele- graph to the “‘weather man” at Wash- ington certain readings and observations, including air pressure, temperature, hu- midity, wind velocity, direction of the wind, amount of rain- or snow-fall, and the kind of clouds in thesky. He records these facts on a map; then, judging by the wind velocity and its direction, and taking into account the other factors, as well as past experience with similar conditions, he predicts for any section of the country what the probable weather will be for the next 36 hours. Checking predictions with actual weather, the “‘weather man’ seems to be right eight or nine times out of ten. Why Dough Is Kneaded If bread should be baked out of un- ¢ kneaded dough, or without yeast or baking-powder, it would turn into a hard, indigestible mass. Kneading makes bread or cake spongelike in structure—that is, full of holes; for the process entraps par- ticles of air, which expand during baking and puff up the dough. In the case of baking-powder, the addition of water causes the tartaric acid in the powder to act on the baking soda (sodium acid carbonate) to generate bubbles of carbon dioxide inside the dough. These, too, expand upon bak- ing, filling the cake with numerous holes. The yeast, as it lives and grows in the dough, gives off carbon dioxide. The result on the dough is the same as before. Sea Breezes and Land Breezes 4 All winds and breezes, except those * caused by the rotation of the earth, are caused by the unequal heating of the air. Water takes longer to grow hot than does land, and will stay hot longer than land. When the sun shines, the air over the land becomes warm very quickly, ex- pands, gets lighter, and therefore rises. To fill in the space which this air occupied, the air over the sea flows in across the land. This sea air is still cool, having been in contact with the water. Thus we have the cool sea breezes by day. But by night the reverse happens. The land cools quickly, but the sea retains its heat. The air over the sea rises and the land air rushes out to fill in the space left vacant. How You Should Breathe In correct breathing, air should enter ¢ as well as leave through the nose. The lining of the nose secretes a layer of mucus which catches fine dust particles before they can enter the windpipe. Hairs which line the nostrils also filter out the coarse dust particles. Furthermore, the long, narrow nose passages warm the incoming air before it reaches the lungs. The Measure of Food Values 6 A calory is the unit by which heat e energy is measured. It is defined as the amount of heat required to raise 1000 grams (2.2 pounds) of water 1° on the cen- tigrade thermometer. Since food is changed into heat, all food values are measured in calories. A baseball player uses up about 6000 calories a day, while a bookkeeper uses about 2600 calories. Lightning and Thunder Ff Every time you disconnect an electric ¢ circuit a spark jumps across the gap. Now, the air always has a great deal of electricity in it. Under proper conditions, this electricity will flow from one point inthe air to another, causing a large electric spark. As the charge of electricity tears its way through the air, great quantities of air are pushed to one side. After the passage, this air rushes back to fill the vacuum produced, thus causing the noise of thunder. Inside of an Electric Iron When an electric current passes ¢ through a wire, the wire becomes warm. A wire made of a certain well known alloy of nickel and chromium gets very hot upon the passage of current through it, yet can support high temperatures. This is the wire used inside of electric irons. The Cause of the Blue Flame When coal is heated in a confined ¢ space, instead of burning it decom- poses without flame, because there is not enough oxygen to support burning. One of the products of this decomposition is illuminating gas. As you open the door the air rushes in, and soon there is the proper mixture of gas and air for burning the gas, which results in a blue flame. The Air and Our Bodies 10 The evaporation of perspiration from our skins absorbs a great deal of heat from the body. Now this evapora- tion will be rapid if the air does not contain much moisture (clear day). The rapid evaporation cools our bodies, which then function normaliy and vigorously. But if the day is damp and muggy, the air already contains so much moisture that very little more can evaporate from our skins into it. This leaves us warm and uncomfortable. lf umn all-r othe dow fire | wate kind pur} the was mur coul bur! rate colu heat a hy colv 100. the the con colt hou ; whi cas’ colt by blo lat] use rar

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ly °~ at 0 n= in it er \- ct ore oO RR O we TS Vee ee (6 — ~ March, 1922 If Fire Came—How Long Would Your Building Last? Uncle Sam Measures Resistance of Beams in a W hite-Hot Furnace and Discovers Concrete Is Best Fireproofing Material ing wooden beams will resist fire longer than unprotected steel col- umns, when under full working load? Do you know that concrete is the best all-round fireproofing material? Uncle Sam has supplied these and many other illuminating facts that will help cut down the nation’s annual half billion dollar fire bill, through a series of severe fire and water tests applied recently to 106 different kinds of building columns. The immediate purpose of the investigation, conducted by the United States Bureau of Standards, was to secure scientific data as a basis for municipal building codes throughout the country. The conditions that would exist in a burning building were reproduced as accu- rately as possible in the tests. Each 12-foot column was placed in a furnace and slowly heated to a maximum of 2300° F., while a hydraulic ram applied to the top of the column a working load or pressure of 100,000 pounds. Pyrometers and deformeters measured the temperatures and the manner in which the columns became distorted under the combination of heat and pressure. If the column still remained undamaged after an hour, a stream of water was turned on it D’ you know that in a burning build- _ while it was still at white heat. Tests were made on unprotected steel, cast iron, concrete-filled pipe, and timber columns, and also on columns where the metal was partially or completely covered by concrete, hollow tile, brick, gypsum block, and single or double layers of metal lath and plaster. The furnace and accessory equipment used were specially designed. The main ram was 36 inches in diameter, and was How various types of full-size concrete-protected columns came through the terrific heat tests is illustrated above connected with a smaller lifting ram. Water maintained at the required pressure of 100,000 pounds by an air compressor was the operating medium. Two stationary and two movable brick walls suspended in_ structural steel frames from overhead beams comprised the furnace walls. These walls were provided with mica- glazed observation holes through which all parts of the column could be observed during the test. Four primary blast burners heated the furnace. From the moment the gas flames were turned on until the point of failure, temperature and soecseepy sseraneesnendeataneeseecans ancora s HYDRAULIC CYLINDER - CONTROL ~. BOARD While the furnace flames baked the building column a hydraulic ram : plied 100000 pounds pressure, as slg in the cut-away view above. hotograph at the left shows mg server watching the effect of = flames through a window in the furnace wall deformation measurements were re- corded. These measurements showed that concrete covering was the best fire resistant because it both insulated the metal beam against heat and helped to carry a portion of the load. As the fire started, the beam first expanded until it bore the entire weight. Before long, however, the metal, softened by the rising temperature, was compressed by the hydraulic ram until a constantly increasing portion of the load was borne by the covering. The resistance of unprotected wooden beams was extraordinary. They usually held out for 25 minutes. This record equals that of a cast iron column or pipe filled with concrete capable of bearing the same load, and far exceeds the fire resistance of structural steel, which failed within 10.minutes after heat was applied.

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pre - . Saad on ses i ibew YUN ee pad <i

to both engine rooms.

© Courtesy Boston Post High pressure pumps enabled Boston firefighters to lay down the barrage of water pictured above. At the right, fire chiefs are telegraphing orders to the pumping station

Firemen Control Pumps by Wire 4 lige use of high pressure pumps which recently made possible a demonstration water barrage 125 feet high and extending en- tirely across a street in Boston, Mass., has necessitated the adoption of a telegraphic signal system by which the chiefs of the firefighters can communicate with the pumping engineer. Three double pumping units have been installed in different parts of the city, each propelled by a 1750-horsepower electric motor directly connected to a rotary pump. These units can be worked singly or together in accordance with the need at the scene of the fire; but where two fires break out at the same time, the two fire chiefs in charge must be able to communicate and to issue uniform orders to the engineers at the pumps. It may be necessary to change the pres- sure under which water is delivered, or to double the volume supplied to one fire. Telegraph at Alarm Box For this purpose the telegraph has been adopted as more reliable than the telephone, and a special wire circuit is carried to fire headquarters from each alarm box. The chief’s chauffeurs are experts in telegraphy, and each carries a portable Morse sounder and key and a microphone set, which he plugs in at the box. A telephone is also provided for minor questions and answers of which it is not necessary to keep a perma- nent record. To prevent conflict of orders the firefighters communicate with the cen- tral office, which in turn relays the orders to the engineer. This system assures an ade- quate supply of water at both fires. One pumping unit can supply 12 hose lines with 4800 gallons of water a minute. This is the volume of water which would be carried by a brook four feet wide and a foot deep flowing as fast as a man walks. Eleven lon deck provide vast traffic accommodations, as shown above Popular Science Monthly | Mammoth Ferry Designed like Bridge PrERRIES designed for use be- tween Oakland and San Fran- cisco, California, offer a novel feature in hull construction, for in cross section they are built like a bridge, with arched steel girders connecting twin hulls. Essentially, this is the principle of the primi- tive catamaran, but because of the == wide, flat deck on top of the con- necting bridge, the boats will be able to carry more automobiles and passengers than has ever been pos- sible with the familiar type of ferry, now overburdened with traffic. As it was not desired to pierce the hull by a smokestack, Diesel engines were adopted. One engine is placed in each hull, with an electric signal system centering in the pilot house, by which the pilot can transmit orders Each hull has its own bow and stern rudder, and as the distance between the propellers and the center line.is unusually great, the boat can be maneuvered readily by the engines alone. These innovations permit ferries of mammoth size which can handle easily the constantly increasing traffic across San Francisco Bay. The two lower decks will be given up to automobiles and trucks, each deck having room for 11 lines of cars. Passengers are carried in light cabins built on the upper deck.

PASSENGER SPACE

arhoee Corer M7 == et a lil

ERS | BRACING HULLS DIESEL ENGINES Twin hulls supporting two vehicle decks and one passen- ger deck are planned for the super-ferry

driveways for vehicles on each

Fish to Climb Dam in a Suction Tube

pireveraqa

AVATERPIPE The flow of water creates a suction that lifts the fish up the tube

Dees their running season schools of fish pass upstream to spawn, and usually some sort of fishway must be pro- vided to permit them to pass dams and other obstructions. One such scheme that is somewhat out of the ordinary has been invented by E. S. Howard, of California. His invention consists of a tube leading from the front of the dam up and over to the water on the other side. Connected with the bottom end of this tube is another pipe which runs to a source of water under pressure. The under side of the bottom end of the conveyor tube is open to allow the fish entrance. When water is allowed to flow from a high level under pressure down to the con- veyor tube, it creates asuction at the lower end. This suction draws the fish that sur- round the tube and lifts them up the con- veyor tube to the top of the dam, where they are dumped into the water.

THE normal adult can hold his breath from 40 to 45 seconds, but this time can be in- creased considerably by training, as in the case of divers. An individual’s breath-holding capacity is affected so markedly by disease of the heart or air passages that it is used in France as a means of diagnosis for bron- chitis or tuberculosis. It is a well-known fact that sufferers from these diseases can rarely hold their breath more than 20 seconds. ~

trou} chiné from ciate newl whic a do two out ¢

car with the the trou new cons abou port the | doo! stee the is: 2 beai pow can and act] in tra

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ily March, 1922 45 e Portable Crane Will Speed Delivery of Your New Car NY automobile dealer needed, since the chassis can who has had _his be suspended in the correct KS troubles unloading ma- position for putting on the eee. ae chines, particularly sedans, from box cars, will appre- ciate the advantages of a newly invented winch with which two men can unload a dozen chasses and mount two bodies in an hour with- out damaging them. The rush and worry to assemble and deliver a new car on time—the grappling with it in the freight yards, wheels. Ordinarily eight men form the crew for unloading auto- mobiles from freight cars. Even then, considerable heavy lifting is required, and there is always the risk that one of the crew will weaken or slip and the body be dropped to the ground. The reduction of the crew and the elimination of the es the damaging scratches to heavy manual labor natu- al the polished body—these rally results in quicker work TS troubles are relieved by the and less damage to the car. id new portable apparatus. It Small as it may seem, the ly consists of a steel I-beam bills dealers must pay for about 10 feet long, sup- refinishing bodies scratched ch ported on a tripod placed on by the unloading crews are an the roof over the freight car said to run into large to door, and held in place by a amounts annually. l1 steel chain that passes down How two men > Bolted to a tow The fact that automc on the other side of the car and and a crane un- car, the device is fastened to the floor beams. By means of the compact, powerful winch one man can raise and lower a body, and even control it so ex- above load a chassis or mount a body is pictured becomes a wrecking crane, as shown in the biles may be assembled in the yard reduces, also, the trucking in connection with inset delivery. When there is no unloading to be done, the beam and the winch may be mounted on rollers or fast- r actly that the automobile may be assembled in the freight yard directly alongside the tracks. No trucks or wooden horses are ened in a general utility truck and used about the garage or as a wrecking crane to bring home damaged automobiles. From Sawdust and Ashes to Fancy Candy Boxes! * candy boxes made from sawdust and ashes, shaped and modelled in delicate artistic forms by a single impress from a stamping machine promise a new use for these waste materials. Instead of being built up by four or five separate operations, each box is completed from the plastic raw material by one blow of the die. with cloth, and even gilded or silvered with genuine-metals. In making the boxes, finely divided coal ash and sawdust are mixed, and a certain amount of sticky binder of a secret chem- ical formula is added. The proportions vary according to the qualities desired in the final product. The inventor claims the material can be manufactured as flexible boxes are painted, but cannot be seen. The ash is added as an inert filler, it is believed, to cheapen the cost of the raw material and to make the completed boxes better able to. take paint or glue. Since the material is plastic when it goes into the presses, the engraved and em- bossed dies can turn out modelled boxes, : even of intricate design. F The finished material, resembling rye as cardboard or as tough as metal, and After leavirig the presses, the marks of “il bread in color and structure, is stronger either waterproof or porous. the stamping machine are trimmed off on d and more easily worked than common Stamping is done with heated dies; and anemery wheel, the boxes are painted with t cardboard. The candy boxes are deco- since the article comes out of the press dry, an air-brush, and then are ready for rated with an ivory finish paint, though in- no drying room is necessary. The heat of market. The cost of the raw material for - deed the new substance lends itself to any the press acts on the chemicals of the these boxes is said to range between a cent - treatment. It can be painted, covered binder, which combine with the sawdust and a half and five cents a pound. “4 into a hard, semi-porous material. The d presence of the ash can be felt before the la = sala N or G Keystone > 7” or ¥ A » d ici e a 1- 4 or z f= = l- e n l= e y e n l= n Here the rough edges of From ashes to boxes! 45 the boxes are eing Here is the remarkable n smoothed out by a rotary Finely ground powder of ashes and sawdust, mixed product coming from the emery wheel with binder, is stamped into artistic forms in the presses illustrated above pressing machine

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EERE abis: toy y me we See, Fe rn Saas SES ey. = eae ea ath on Se OY 46 Popular Science Monthly Do You Know How You Laugh, Cry, Sneeze, Cough, and Snore? ie is almost impossible to | fake a laugh or a cry so naturally that any one will be deceived. The ear in- stantly detects a false note. Even the most skilful actors and singers never quite succeed. The difficulty lies in the depressed fact that laughing and cry- ing are naturally produced largely by the involuntary SNORING muscles, and because all The soft palate forms of “abnormal respi- is vibeates ration,”’ as they are called, are much more complicated operations than is generally supposed. COUGHING When You Laugh A laugh, for example, is produced by holding the vocal cords tense and pro- ducing a clear resounding note by forcing a series of short expiratory blasts against them. A _ hearty laugh may include as well the vibration of the larynx and pharynx. In crying, you partially close the glottis, the slitlike opening into the larynx, and take a short deep inspira- tion and a prolonged ex- piration. If the crying lasts long enough, there is a sud- SOBBING CLEARING THE / THROAT The soft palate is The glottis is first closed and then blown open by a vio- lent expiration The glottis is partly closed How ‘Involuntary’? Actions Happen LAUGHING The vocal cords are held taut and close to- gether The locations of the organs involved in producing various complicated muscular acts, such as laughing, crying, and sneezing, are shown in the above cross- sectional diagram SNEEZING A violent blast is forced through the nose passage driven from the lungs and forced between the narrow space between the root of the tongue and the de- pressed soft palate. A sneeze consists of an inspiration, often very rapid, and then a sudden blast directed through the nose. The glottis remains open throughout the opera- tion. In snoring, an unusually steady and prolonged in- spiration and expiration is set going through the open mouth until the soft palate and uvula are set in motion by the vibration of the air currents. A hiccough is an inspira- tion due to a spasmodic con- traction of the diaphragm suddenly checked by closing the glottis. Imitations Difficult In every case the sound is caused by a complicated series of interactions be- tween groups of muscles at different points along the respiratory system, only a few of which we are able to control at will. For this reason our polite laughs sound forced. den spasmodic contraction of the diaphragm resulting in the abrupt inspiration and expiration sounds in the larynx and pharynx, famil- iarly known as sobbing. To cough, one first takes a deep breath, then partially closes the glottis, and directs against it a violent expiratory blast which forces the glottis open and expels any mucus or other irritating matter accumulated in the air passages. In clearing the throat a current of air is The difficulty of con- vincingly imitating crying, either as an expression of sorrow or joy, is complicated by the fact that the purely muscular act of crying is accompanied by a sympathetic excitation of the tear glands, causing tears to fall. Are X-Rays Outclassed by Powerful New “Odic Ray”? ISCOVERY of “odic rays’ of high penetration produced simply by the electric current drawn from an ordinary light socket, and yet with the curative and medicinal value of X-rays, is claimed by Dr. Edgar L. Hollingshead, of Pasadena, Calif. intensity and penetration than any pre- viously known to science. The rate of vi- bration of the ‘‘odic rays’? can be con- trolled by the operator, it is asserted. If these claims are substantiated, the © value of the discovery to the world will be enormous. The medical -profession will have an unlimited supply of curative rays. The X-ray diagnosis can be utilized by every doctor in the country, since the apparatus can readily be carried from, house to house. With simple, inexpensive apparatus he is reported to have passed rays through 114% inches of lead and 41% inches of steel, at such strength as to sear dental X-ray films encased in tinfoil. Such an achievement ap- ; pears impossible; yet X-rays seemed equally impossible when Réntgen first announced their discovery. Doctor Hol- lingshead’s claims are based on tests made in the presence of eyewitnesses who selected at random the films exposed to the rays, retained the dupli- cates, and developed the two simultaneously in the presence of an unprejudiced committee. After exposure, these films were found to be perceptibly darkened. Doctor Hollingshead de- clares that the rays produced by his apparatus are of greater + +08 “o's The doctor has given a par- tial explanation of his ray. He has found, he says, that electricity is not simply a force, but a substance. Amper- age, he adds, is the substance part of electricity and voltage the speed. Like any other sub- stance, electricity is composed of vibrating molecules, atoms, electrons, and other infinites- imal units, and the form that the substance takes is due to the rates of atomic speed. The only differences between one ray of light and another are in wave lengths or vibra- tion, speed of discharge, and Above is the “odic-ray gun’? with Doctor Hollingshead, known as the discoverer of the ray, directin penetration of 4% inches of steel and 11% inches of lead. At the left is shown the carrying case for a 1 *‘odic ray’’ projector polarity. Assuming that elec- tricity is like water flowing the through a pipe, and that its voltage is the speed with which it travels, he first intensifies its atomic speed, then he breaks it up, releasing a force or ray of great speed and power. Mara at Gy webted feet

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1is hs n- 1g, ly ya ds, at er- 1ce ge ib- ed ns, es- lat its its it March, 1922 47 r How Machines Make Magic Carpets from Oil and Cork A HALF a century ago a young inventor noticed that the film ona can of paint was tough. He exposed linseed oil to the air, oxidizing it, then mixed i k Ps OE oN n cork and gum, and produced a substance that could i cate’ de be rolled out, like a pie-crust, into a carpet. Today signs or “cuts” linoleum, which he thus originated, is manufactured by for printing lin- the machinery pictured on this page. oleum carpet In the color-de- sign department Heated rollers weighing 26 tons each, press into burlap a cement composition of oxidized linseed oil, cork, and gum, forming a waterproof floor-covering. Above is shown one of the presses Operated on a track, so that they can be moved from one end of the building to another, the printing-presses shown in the photograph above stamp color designs on wide sheets of linoleum Here in the oxidizing sheds, boiled linseed oil drips from a conveyor to sheets of scrim that hang from the ceiling. Heat and oxygen turn the oil into semi-solid form Above are three of the vats in which linseed oil, one of the principal ingredients of linoleum, is boiled. From the vats the oil is pumped to the oxidizing sheds Fresh from the _ printing- press, the sheet of linoleum is hung in loops to dry in a chamber or ‘‘stove” heated to 100 degrees. Above is a top view of the “‘stove’”’ A pile of linoleum cement just after it has been poured from a vat for cooling may be seen in the photograph at the left. When dry, the cement looks like marshmallow The semi-solid linseed oil on the oxidizing sheets is mashed and mixed with rosin and gum into a cement or binder that will hold the pulverized cork together —

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© Mirzaoft Motor Ambulance Carries First Aid to Injured Dogs OGS injured by autos on the roads near London, England, now are cared Floating Crane Handles 150 Ton Bridge Like Plaything oo bridge was a light load for the mammoth floating crane belonging to an English shipyard on the Mersey River. The bridge was picked bodily from its abutments, placed on a barge, and towed down the river to Seacombe for re- pairs. This is believed to be one of the heaviest weights ever lifted by a floating crane. The bridge was raised with the second tackle and run out well toward the top of the crane arm. Had it been neces- sary the crane could have lifted the heavy bridge 75 feet into the air. These floating cranes are ordinarily used to place in position the engines and other internal machinery of ocean liners. Popular Science Monthly

Cyclecar Sells Complete for Fifty Dollars pt thousand marks—approximately for by a motor ambulance. A veterinary gives first aid on the spot, and if there is hope of saving the life of the pet, it is placed on a thick bed of straw and carried to a kennel for further treatment. The ambulance is ready for service day and night, and is summoned by telephone. All the farmers living near the roads in the dis- trict outside of London cov- ered by this service notify headquarters as soon as they are aware that an accident has taken place, and the cyclecar imme- diately starts. XILITE, 2 new insulation material, is being pro- duced in Venice. Itisa resinous compound man- ufactured synthetically and has been found to be particularly well suited as a substitute for wood in tool handles. Button- Ko = Lee nh, makers are also using it — .

fifty dollars at present exchange rates—is the price asked by its German makers for a new-type automobile. The car isn’t big, and the sides are made of wooden slats, nicely varnished; but for all that it is big enough for one person, has a real engine, and is exceedingly light weight. The car is practically a motorcycle power engine installed in the sim- plest possible automobile body. It will be noticed, however, that the usual features of auto con- struction are present, and axles, steering knuckles, springs, are similar to those of the larger cars except for size. The ridiculously low price includes head- lights and horn. ONLY two out of every thousand automobile ac- cidents are really un- avoidable, according to a a survey conducted by a See the Auto Club of south- — ern California. Twenty-

five per cent of all the

in place of better known bone and shells. The floating shipyard crane picked up the entire bridge span weighing tons, swung it around and placed it in position on a barge accidents are caused by carelessness.

Logs Hauled from Lake Bottom with Line and Nail HOMEMADE “hook and line” salvaging outfit, attached to a rowboat, has fished thousands of dollars’ worth of ‘“‘dead- head”’ logs from the bottom of a small lake in northern Wisconsin. The essential part of the fishing tackle is a tenpenny nail, which is driven into a 'og by a hammer operated from the boat. The nail is clamped in the end of an iron rod to which a sliding weight is attached, and the whole outfit is lowered into the water until the point of the nail rests on a sunken log. Then the operator pulls the weight up the rod and lets it fall repeatedly, hammering the nail into the wood. The log can be raised by pulling on the wire cable by which the device is lowered. When near the surface it is caught in a wire noose and dragged ashore.

Wire Net at Grade Crossing Stops Reckless Motorists | penepimaioan safety gates of wire rope, which fall as a train enters the nearest electric block, have been installed to guard several bridges and grade crossings in Chicago, and so prevent the fool- hardy motorist from risking his life at these points. Even if the gates are struck by an auto traveling at high speed, the ropes will hold and prevent the car from getting on the tracks. Enough slack is left in the network so that the gate will give before any shock and check the moving vehicle gradually. More than 1500 persons were killed and nearly ‘three times that number were seriously injured in grade- crossing accidents during the past year, according to railroad statistics. The new safety gates rep- resent an attempt to reduce this toll. © U.&U.

When a log is located, the nail is driven into it by means of the string and sliding weight shown in the insert The latest safety device for railroad crossings is a flexible gate that will stop an automobile traveling at high speed

Mar

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March, 1922 49

| be there something on this page that arouses your curiosity? Write and ask about it. Our Service Department will be glad to answer your inquiries. een

Grapes Flourish on Sand Dunes NE of the most unusual vineyards in France, per- haps in the whole world, is found in Anglet, on the Mediterra- nean. The grapes are grown on the sand-dunes a few feet from the seashore. Many attempts were made to utilize the im- mense wastes of the seashore, but without avail. About ten years ago M. Dumail experi- mented by planting young grape-vines upon a piece of property which he acquired gratis, near the famous light- house of Biarritz. The main difficulty of plant- ing grape-vines by the seashore is the winter storms and winds that blow off the sea toward the land, shifting the sand from one place to another. To prevent his vine stock from being up- rooted by the winter gales, M. behind them planted branches from tamarind trees. These took root, and grew into a solid wall, impenetrable to sand.

THE arid deserts of Western Australia are being irrigated by artesian wells.

Scaffolding Veils French Church Dumail erected high fences and UNABLE to swing scaffolds on ropes from the towers and roof, because of the statuary, carvings, and grillwork cut in the stone, masons working on the historic church of the : Trinity in Paris covered the entire building with scaffolding the other, the pupil not only before pointing up the masonry. ; The stonework had deteriorated to such an extent that the ; church practically had to be rebuilt. Wherever possible, the ment. When one knee is bent, outer stone facings were removed and replaced by new stone cut from the same quarry.

How to Dance Out the Week’s Wash (5 taceree dancing is easy for any one who will prac- tice assiduously—with a wash- ing machine. Such, at least, is the advice of Clifford G. Sweet, of San Diego, Calif., a veacher of dancing, who has invented a washing machine with which the housewife can perfect herself in the terpsichorean art without interfering with household du- ties. The machine has long, upright levers pivoted to bars that ex- tend under the bench on which the tub rests. On the upper portion of the levers are bracket arms carrying the suction plung- ers used in washing machines. The levers, spaced well apart, are connected and move simul- taneously—and here’s where the dancing practice comes in. By grasping a lever in each hand and swinging from side to side, bending first one knee and then washes the clothes but practices a fundamental dancing move- the other leg of the pupil remains straight, with the toe pointed.

‘“$Old Timer’”’ Still Puffs and Pulls PrORTY-six years of hauling trains have not worn out a loco- motive still in service on the Lake Tahoe Railway in California. The old timer continues to operate today as evidence of the dur- ability of American-made machines. The locomotive was the latest thing in engine building when it left the maker’s shops in 1875, and although it has done duty continuously ever since, the original boiler and machinery are still , in good working order. The engine went West when the first trans- continental railway was new.

J ; ‘ ee sk Dc tl pet “4 " i / wy 4 a * Will the locomotives of to-day last as long as this one? After 46 years of active service, it is still hauling trains in California Strange Walls Guard Tibetan Valleys = explorers who attempted to scale Mount Everest dis- covered, among other things, several ancient fortifications built in unexpected places in the high Tibetan mountain valleys, 15,000 feet above sea level. Partly to protect the fields from being washed away by moun- tain freshets and partly to guard against raids by enemy tribes, walls 20 feet high and often mcre than a mile long, guarded by strange round watch towers, were constructed at intervals at the head of these fertile valleys. te a

M t Everest explorers discovered this stone wall and wanali sone <* high Tibet, where it has stood for more than a thousand years

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50 Popular Science Monthly Radio Store Provides Free Clubroom for Wireless Amateurs N the back of a retail electri- cal store located in the sky- scraper section of New York City, there is a unique club- room for radio amateurs. A full set of radio receiving equip- ment has been installed with an aerial on the roof. Appara- tus can be tested out in actual practice, and the visiting ama- teur is given the privilege of taking any piece of apparatus from stock to connect up and use as he sees fit. The em- ployees of the store make no demonstrate, he can step to the blackboard and sketch it out with the other amateurs present giving criticism and argument. Sometimes, if one is lucky, one. may meet some of the experts from the big wireless companies, and get the latest “‘dope”’ direct. By promoting interest in attempt whatever to sell goods to the amateurs using the club- room. Even if the visitor asks for information, it is given without any intimation that he In this unique radio store, amateurs take any piece of equip- ment from the shelves and carry it to the club- may radio, the clubroom has proved a moneymaker for the store. The goods sell themselves, for by listening to the conversa- tions in the clubroom the be- ginner in wireless finds out what he needs for a first class station, and goes out into the store and buys it. He has learned the right name, too, is expected to buy. Amateurs who live many miles apart and who know each other only via wireless, form a habit of dropping into the club and talking over their installations. If room in the rear. An aerial is provided so that amateurs can test their sets and does not waste the clerks’ time nor compel the salesman to give a curtain lecture on electricity and magnetism ls every time a receiver is sold. Best of all, the clubroom gives the ama- wishes to learn the standard connections, ' 3 : one has a new idea in hook-ups, there is there are blueprints on the walls. If a teurs a chance to exchange ideas and coul a chance to test it out. If a newcomer “club member” has a theory of radio to stimulates their interest in radio. yarc siste ° o e whi Linemen Use Portable Machine Cuts Whole Gear at One Time abo . e p Floodlights at Night [ DIFFERING from other types in that gradually fed in by successive cuts of the 50 f it cuts all the teeth in a gear at one’ tooth. T time, a multiple gear-cutting machine has At the completion of each stroke of the por been developed by an Indiana manufac- ramand before the next cut begins, the gear oak turer. blank is indexed a space equal to one tooth, and The machine operates much like a ver- thereby presenting a different tool to each att: tical shaper, except that the tools are held tooth from the one that made the previous pol stationary and the gear blank is recipro- cut. After the tools have been fed in to the cated past them. The mechanism consists full depth, they are held stationary in that the of a ram carrying a blank supporting arbor position while the cutting process con- ] and the multiple tooled head. In position, san the machine is seven feet in height, and the weighs 17,000 pounds. When operating at pel full capacity, it is driven by a 100-horse- des power motor, col The tool head, which is the most interest- ma ing part of the machine, is a flat steel disk me INEMEN of an electric-light company three feet in diameter, with a hole at the up in Detroit use an old truck for an center and a number of radial grooves cut a emergency lighting equipment for night in its face in which the tool bits are ar- bir repairs. A complete generating set con- ranged about the circumference of the gear an sisting of a direct-current, 120-volt like spokes of a wheel. An annular sec- co! dynamo, directly connected with an air- tional cam ring gives successive feeding wi cooled engine, of one-kilowatt capacity, is movements to the tools. The tools are du mounted on the vehicle. it Floodlights with 15-inch re- flectors and 250-watt lamps th illuminate the scene of the he repair. When the doors of the m body are locked, these lights The cutter head, showing T are secured in clips in their the radial grooves in which se : : ; the tools are arranged aie compartments, insuring their in readiness for service when the : , ; th job is reached. The reel for tinues until the gear has in- tr in-aken weed ‘comien 2000 dexed one complete revolution th feet of twin conductor. and thus each tool takes one se last cut on each tooth. fo IN England, chalk, blended with a rich carbonaceous ma- terial, the basis of which is coal-tar, and molded in bri- quettes, is being used as a fuel substitute. It is reported that the fuel gives out greater heat than coal, burns more evenly and for a longer time, and produces a minimum of ash. The chalk is employed to conserve the heat and make the fuel more lasting. Gr CoS) — 2. én. ,.~A. sas The multiple gear-cutter as it appears in operation. e men on the platform are standing in front of the multi-tooled head This final complete index insures a uniformity of spacing of the teeth in the gear equal to that of the indexing mech- anism. It is claimed that uni- formity of the tooth form is secured even when the tools themselves may be far from uniform, because if any tool is longer or wider than any other, even if only by a thou- sandth of an inch, that pro- jecting portion will take one last cut on the corresponding part of each tooth in the gear. Popular Science Monthly

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ly "3 © iceroR ww. a SED March, 1922 Portable Bin Speeds Up Roadbuilding NTELLIGENT planning of a material yard and the use of a portable aggregate pin that saved the seconds in loading ma- terial recently enabled a crew of 53 green men to lay a mile of 18-foot concrete road in nine working days in the course of a state highway job in Wisconsin. Nearly two months before the mixer was on the job, all the sand and stone that PORTABLE BINS CONCRETE MIXER AND PAVER How the plant was laid out for rapid )paving work is shown above could be obtained was piled in the storage yard. The mechanical equipment here con- sisted of a crane with a 40-foot boom, which unloaded the sand into a pile about 20 feet wide at the base, and placed the stone in a parallel pile about 50 feet wide. To obtain the greatest loading speed, a portable aggregate bin was built of white oak, about 14 feet square and 18 feet high, and mounted on road wheels. It was attached to the crane by a rigid 10-foot pole, so that it followed the movements of the crane and made it unnecessary to peak the boom at any time. Forty yards of aggregate, 15 yards of sand, and 25 yards of stone were carried in the bin at all times. Two measuring hop- pers were mounted below the bin floor, so designed that a mixture of any proportion could be delivered to the trucks by the manipulation of levers, controlled by one man from a platform, that operated the upper and lower cut-off gates. Each truck after it had backed under the bin and received a carefully measured amount of aggregate in each of its two compartments, drove to the cement shed, where two and a half barrels of cement were dumped on top of the aggregate. Thence it proceeded to the site of the work. Here the truck backed into the skip of the paver, discharged half the load, and moved forward two feet. The skip was raised, sending the material into the mixer, and then lowered again. The y, truck again backed into the skip, discharged the second batch, and left for a new load. Each truck, as it backs under the portable bin, receives an accurately measured amount of aggregate; then drives to the cement shed March, 1922 51 om DULL RED FAINT ae GLOW (NO FLASH) A moment after the shell bursts, an 800,000-candlepower light is sus- pended from a parachute 1000 feet high, illuminating the enemy battleship Star Shell Replaces Navy Searchlight A SHELL explodes 1000 feet above an enemy war-ship; immediately the vessel is flooded with dazzling beams from an 800,000-candlepower light that illumi- nates the sea for miles. Such, in naval warfare, would be the effect of a special type star shell recently adopt- ed by the American navy to supplant the searchlight for night lighting at sea. The new shell is a development from the trench star shell used dur- ing the war. It is fired from a three-, four-, or five- inch gun using a new flashless ex- plosive. The tim- ing fuse of the shell, after detona- tion, lights a pow- erful lamp and ex- pels a parachute that keeps’ the light at a height for a full half min- ute. The advan- tage of the star shell is that there is no flash from the gun firing it. The new shell is loaded into a gun and fired. It has a range of six miles. For the larger guns the shell does not work so well, because of the character of the new ex- plosive; but with the three-inch and smaller guns, it functions almost perfectly. When the shell is fired from the three- inch gun, only a ball of very white smoke issues from the muzzle. This ball of smoke is hardly visible at 500 yards from the ship. With the five-inch gun, however, there is a dull flash that might possibly be recognized by an enemy at long range. Stained Glass Dies of Disease LASS seems to die of disease, like a living thing. An unknown malady is attacking the stained-glass panes of cathe- dral windows in Europe. The sickness makes the colors deepen, and the glass flakes off in small pieces until the panes are as thin as tissue-paper and will crumble at a touch. The effect of rapid vibrations from the music of the organ is suggested as a cause, but it seems equally probable that the dis- ease is a little-understood effect of the actinic rays of sunlight—comparable, per- haps, to the radium and X-ray emanations that turn clear glass a deep purple. 5434

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How the hood unfolds as its uprights slide along rods on each side of the bus is shown in the upper photo- graph, Below is the folded hood in its receptacle OLDING down in front of the driver when not in use, a hood now carried by London buses can be raised instantly to protect the passengers against a sudden shower. The arrangement is extremely simple. The hood is supported upon wooden uprights, which slide along a brass rod attached to the rail of the bus, while the cover itself folds up like a concertina. At the forward end of the coach, the sup- ports fall forward on hinges and the hood drops into a receptacle behind the glass wind-shield.

Novel ‘‘Safety’’ Gas-Heater Both Warms and Lights Room "TBE fact that highly poisonous carbon monoxide gas is given off to some de- gree by almost all forms of gas-heaters is responsible for the general feeling that it is dangerous to burn gas-heaters in confined spaces. This new heater of French inven- tion is said to produce no carbon monox- _ ide whatever. The gas is thoroughly mixed with air in its passage through a series of cone-shaped openings, and is burned as it passes through the fine meshes in a wire screen. This makes the burner consist of nearly 20,000 tiny Bunsen burners and results in com- plete combustion. A core of refractory earth is heated by the flame so that the gas from an ordinary incandescent mantle will give <2 temperature of over 1000° F., mak-

The mixture of gas and air burns as it passes through a wire screen ing this device a heating unit of the first order. The incandescent mantle and core also give as much light as a Welsbach mantle.

‘© Engineering and Mining Journal Lumber-Yard Uses Air Engine for Hoisting FRoLTse directly to the mast of a boom derrick, and hence occupying no ground space, a novel compressed-air hoisting engine installed in a Western lumber-yard attains unusual hoisting speed for an engine of such simple design. It consists simply of an air cylinder six feet long. On the bottom head of the air cylinder are mounted two sheaves and bearings. A third sheave is placed on the top of the piston-rod, bolted to the cross- head that works in a pair of guides attached to the derrick mast above the cylinder. When air is turned on, the piston rises for a total stroke of six feet. The arrange- ment of the sheaves converts this into a cable lift of}24 feet. The cylinder is about ten inches in diameter. Popular Science M onthly Rubber Spring Blocks Absorb Motor-Bus Jolts 2 Uaeee spring blocks replace the usual spring shackles in an auto-bus model now being manufactured. Buses so equipped ride as easily as the best of tour- ing-cars, it is claimed. The end of the spring is inserted in a large block of very resilient rubber, which is held fast in a housing riveted to the chassis frame. In order that the springs may also carry their proper share of the load, lipped plates are bolted to the ends of the two-top spring leaves. These plates fit into the spring block, which encloses the lips. Stretching the block in this manner puts the upper and lower members of the block under a compression of about 100 pounds to the square inch when bolted up. The rubber block acts very much like a shock absorber of the cushion type,

RUBBER although in this case the spring pad is always in compression. The designers claim that the rubber blocks are easier to replace than the bushings and pins of the ordinary form of spring suspension, and that the life of the block in service is over 30,000 miles.

Detachable Blade Converts Hammer into Hatchet COMBINA- TION hammer and hatchet has been invented by Stuart Moseworthy, of Cambridge, Mas- sachusetts, for the use of carpenters working in incon- venient and high

As a special service to readers, the Editor will be glad to supply the names and addresses of manufacturers of devices mentioned in Popular Science Monthly

places where it is desirable to carry as few tools as possible. The hatchet blade is re- cessed to fit the hammer face, and a clamping-bolt is inserted through holes drilled in the jaws of the blade and the hammer head. Side clips are also provided that further secure the hatchet blade to the rest of the tool when it is being used as a hatchet. A guard for the cutting edge protects the blade when the tool is placed in the pocket or when the hatchet part is re- moved to use the tool asa hammer. ~«

the grap centé a mo and g as t! shac thir: bee pro’ thei any NE fro}

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the bus $0 ur- the ary la Ty tes op he DS. its ck ds am: ) atte | a i | SS ae Sl a oe March, 1922 Twenty-Mile Voyage in Motor- Cycle Side-Car reed JOHNSON and John E. Hogg, of Los Angeles, paddled twenty miles in the side-cars of their motorcycles. For hours they were out of sight of land. They came to the Salton Sea to photo- graph wild birds on the island in its center. Finding themselves unable to hire a motorboat, they caulked up the side-cars and set out. The voyage took aJl day, and Two photon, seeking bird views paddled twenty miles in motorcycle side cars as the temperature was 125 degrees in the shade, their sufferings from heat and thirst were intense. There would have been no possibility of rescue if their im- provised boats had capsized, but they got their pictures and paddled back without any accident whatever. NEw rrench coinage to replace the paper money now in circulation will be made from an alloy of bronze and aluminum. Windows Are Washed from Suspended Tram-Car O chance for a washer to fall from the windows of a factory recently erected in Cleveland, Ohio. A light carrier-car is swung on two wire ropes from a rail running entirely around the building, under the eaves. Two small winches enable the platform to be raised or lowered to any desired height, and two trolley rollers supported by the rail permit the cage to be moved from window to window. There are 4600 windows in the building illustrated, and they may be cleaned by three men in twelve days with the assist- ance of this equipment, at a cost of $172.80. Without the use of the car, it would be necessary to erect scaffolding for this job, and the cost would be not less than $800, according to the engineers who installed the device. The carrier is electrically operated on the monorail. Will the Egg Grow Up to Be a Hen or a Rooster? s fenapiriagu an egg is a potential rooster or an embryonic hen can be determined, it is claimed, by a “‘sexom- eter’ which may prove to be of value in the poultry industry, for when the sex of eggs can be told, it will be possible to send most of the rooster eggs to market and retain the hen eggs for the upbuilding of the home flock. The “sexometer’’ consists of a piece of cork wound with copper wire from which is suspended a pendulum of wire ending in a flat piece of aluminum-plated substance. In examining the egg, the cork is held in one hand and the egg in the other. If the egg is male, the pendulum, it is claimed, will swing in a circle. If it is female, the pendulum is said to swing back and forth. It has been demonstrated that the device, when held over one egg, will swing in a circle; yet when it is held over an- other, it will swing back and forth. Whether these varying motions are due to the sex o1 the egg, or to such incidental qualities as shape and size, is a puzzle that no one has been able to answer. The inventor claims that in experiments cover- ing a period of six months, the instrument forecasts on 85 per cent of the eggs tested were correct. A permanent window washing trolley saves thousands of dollars annually in keep- ing the 4600 windows of this factory clean. he monorail does not detract from the building’s appearance 58 Bicycle and Wheel Chair Become Jaunting-Car BICYCLE with a motor attachment, and a wheel chair for a trailer is the combination that makes up the latest jaunting-car. The trailer is attached to the bicycle by means of a curved piece of iron pipe leading to a universal joint under the saddle. The feature of the motor is the vertical drive, attached to the front wheel of the A small motor on the front wheel post supplies enough power for bicycle and trailer bicycle. No change has been made in the rear wheel. The rider must be careful not to turn corners too sharply, or the trailer will overrun the bicycle. Machine Tests Hardness of the Thinnest Metals EVELOPED for use with material too thin to withstand testing by the standard ten-millimeter ball of the Brinell method, compara- tive tests made in the Woolwich Ar- senal, England, have shown a newly developed machine to be equally accu- rate. It was in- vented during the war to test the walls of small-arm car- tridges after they had been loaded with powder. The standard Brinell method is followed in principle in this machine, the difference lying in the use of small balls and small loads. The balls used are one and two millimeters in diameter, and the loads range up to fifty kilograms. The object to be tested is placed on the table, and raised or lowered by the hand wheel until it bears against the ball- holder on the crosshead. Finer adjust- ments are effected by leveling screws on the base plate and a fine-pitch non-rotat- ing screw on the ball-holder, operated by the upper hand wheel. The proper weights are then placed in the lower part of the suspension stirrup to which the ball holder is attached. The maker claims this instru- ment will determine the hardness of ma- terial, a hundredth of an inch thick. Balls only two millimeters in diameter and loads up to fifty kilograms are used in this ma- chine to test the hardness of very thin metals THE demand for turpentine requires 800,- 000 acres of virgin forest annually.

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ELD, 2 IRA tla i Ani RA TT Knock-Down Toaster Fits Traveler’s Grip AKING up a space only ten by six by two inches in the traveler’s grip, a novel folding toaster can be quickly trans- formed into a standard size utensil. The legs fold out of the way against the frame, which is recessed so that the legs will not project and tear articles near them. The base of the body is grooved, and into this fits a removable shelf for catching crumbs and grease. The toaster tray can be taken out for broiling or light cooking. New Gearless Steering-Gear Is Always Tight GEARLESS, irreversible steering- gear in which the shaft is directly con- nected with a spiral cam acting on a roller that operates the “‘linkage,”’ has recently been perfected in England. The new de- sign is said to be easier to operate than the usual steering-gear, and to eliminate back- STEERING COLUMN 7 UPPER CAM A ROADWAY ‘ LOWER CAM ROADWAY How the spiral cam takes the place of gears 4 =) TO STEERING KNUCKLE { : j — ae, | lash altogether. Due to the fact that large surfaces in rolling contact are substituted for small surfaces in sliding contact, wear is imperceptible and the steering-gear is always tight. The roller is pivoted at right angles to the shaft that moves the drop-arm. The drop-arm, found on all steering-gears, is the short lever attached to the shaft that moves the linkage running to the front wheels. In this model a dual cam, or a double roadway in which the roller can travel, is necessary to hold it solidly. This double spiral roadway forms an are, and is so designed that when the wheel is cramped to the right, the roller is at the extreme top of the pathway, and when cramped to the left, the roller moves to the very bottom. These inclined pathways act like a screw-jack, and make additional gearing in the steering-wheel unnecessary. Ball bearings are used throughout, even in the cam-roller. Telltale Light on Lamp-Post Prevents Accidents T° prevent collisions between fast- moving automobiles and dark lamp- posts on winding roads, C. G. Beckwith, of Cleveland, has invented a boulevard standard with bull’s-eyes of colored glass about one third of the way up the post. When the main light is burning, the Bull’s-eye lights flash a warning telltale lamp behind the bull’s-eye gives only a faint glow, but if the main lamp fails, the telltale lamp is automatically subjected to greater voltage and shines brightly. l.iotor Pusher Saves Legwork FULL-SIZE one-cylinder motorcycle engine makes this bicycle attachment unusually powerful. A very low gear is used to keep the speed moderate. A hinged and pivoted joint behind the saddle enables the power unit to rise and Plenty of power for the cyclist is sup- plied by this one “‘cylinder pusher’’ fall in conforming to irregularities in the road. Flexible wires are led from the engine up the connecting piece and along the frame of the bicycle to the handle-bars, so that the engine is controlled in much the same manner as a motorcycle. Popular Science Monthly ' Py Air Dinas Runs Jack for Motor-Car PNEUMATIC jack, operated by compressed air from an ordinary free air hose or the engine tire pump, will lift acar without any manual labor whatever, The mechanism consists simply of a heavy cast-steel piston and a large piston-head attached to a rod that extends upward through a hole in the cover. ‘Air is admitted to the under side of the piston. After the car has been lifted the required amount, a turncock on the air line is closed, and the car held in place by slipping a steel pin through one of the numerous holes bored in the piston-rod. The device is made in three sizes to lift 2200, 4200, and 8000 pounds, but all models operate on the same air pressure. If necessary, the power can be supplied with a hand pump, but the device is designed especially for cars equipped with some mechanical means for compressing air. Automatic Air Compressor Starts Instantaneously BETTER tank mounting and a magnetic air-pressure release are the improve- ments in an automatic air compressor for garages and service stations requiring con- stant pressure in air lines. The magnetic pressure release enables the motor to start without a load. This assures instantaneous starting and a small initial consumption of current. The air pump is of the rotary type, and is driven directly from a low-speed, ball- bearing compressor-type motor built di- rectly into the pump. No gears are employed. It is possible to mount the compressor unit on the top of the air- storage tank, reducing the floor space occupied by the machine. A COLD method of making porcelain in which the material is not fired in the kiln, is reported from Germany. The hardening process is a secret. « —_—=,. -« ‘? a Popular Science Monthly of bac jav an of tin len FE ciz re

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or l by y free ll lift ever, avy head ward itted lired osed, steel ored le in 8000 ame can the cars Pans tic ye- for les nis it ll- li- re he ce in 1g — * March, 1922 Compact Threading Machine Weighs Only Ninety Pounds BENCH threading machine that weighs only 90 pounds and takes up but 914 by 29 inches of space on a bench, consists of a single casting, carrying a spindle mounted on bronze bearings. The spindle is driven by a three-step cone pulley and carries a self-opening rotary die-head operated by a yoke lever and trip- rod. Adjustable stops arranged on the trip-rod govern the point of opening and closing of the die-head. A forward motion The threading ma- chine is less than ten inches wide of the carriage opens the die-head and a backward motion closes it. The carriage is equipped with a two- jawed chuck operated by a hand wheel, and an adjustable swinging stop on the side of the chuck provides for an accurate set- ting of the work for a predetermined length of thread. FEEDING yeast to laying hens is not benefi- cial, and ultimately decreases their egg yield, reports the Department of Agriculture. Cah PO OO News Photographers’ Auto Is an Oversized Camera ee newspaper photogra- phers of Atlantic City, New Jersey, have installed an auto body modeled after a camera, from which they take pictures of the news events in that vicinity. In addi- tion to its advertising value, the odd body provides space for a darkroom in which plates may be developed on the way back to the office. A ladder in the interior leads to a plat- form at the top of the huge “‘camera’’ 10 feet above the ground. This elevation enables the camera men to get unusually effective pictures of crowds and sporting events. “Creeper” Adds Comfort to Work under the Car RAWLING under the car to make re- mounted in a channel-iron frame, and is pairs is a pleasanter task when ther fitted with a leather-upholstered cushion mechanic can lie on a comfortable creeper. The newest improvement in this field is a folding creeper that can be converted into a seat to eliminate stooping and kn2eling when repairs are made near the floor. The invention is made of wooden slats head support. When used as a creeper, the seat lies flat, and the whole device is only one and one half inches high. Rollers on the bottom ‘of the frame permit the mechanic to shift it to any position under the car and to. move readily from one point to another. In converting the device into a seat, one foot is placed upon the lower end of the platform, and the upper end carrying the cushion is lifted up, caught by four diagonal braces that slide in slots in the iron frame, and locked when a lug drops into a de- pression at the end of the slot. The outside frame dimensions are 36 by 15 inches. When not in use, the light creeper may be hung on a hook on the wall of the garage. Above—Folded into a seat, the creeper does away with seeping orkneeling. Below— When you can rest your head on an upholstered support, wor as = tnnn under the car is easier 55 Machine Aids One-Armed Man to Shuffle and Deal Cards Ce and the folding card-rack on this machine take the place of one of the player’s hands. By its use a one- armed man can enjoy a game of cards without being embarrassed by any awk- wardness or slowness in dealing. After dealing, cards are held with their lower edges placed in a semicircular groove just back of the dealing device. In shuffling the cards, they are placed between the side flaps and riffled by taking a number from the bottom of the pack and throwing them upon the top with a jerking motion of the fingers—exactly as it would be done with two hands. To deal, the pack is pressed against one of the side pieces by Just back of the dealing-rack is the circular groove that holds the cards the fourth and fifth fingers, and the cards dealt out with the thumb and forefinger. The device has been tested by disabled veterans and found highly satisfactory. Adjustable Auger Handle Helps in Cramped Spaces An auger handle with the adaptability of a ratchet brace, which facilitates boring in cramped and restricted spaces, has been invented by Mr. W. H. Stiner, of Kennett Square, Pa. The handle can Two of the four positions in which the new auger handle can be used be used in fvuur different positions. In the open, it is used as an ordinary auger handle with both arms horizontal, but if need arises, either arm can be mounted above the bit-clamp to serve as a pivot, and the bit turned with the other arm alone. This feature makes it possible to use the tool in half the usual space. The ratchet feature can be applied on either side, or in either direction, and is useful where machinery or walls prevent the carpenter from turning the handle in a complete circle. FARMERS have begun to compete with coal- miners, for corn at 20 cents a bushel is equivalent in heat value to coal at $10 a ton. Corn is excellent fuel. Pound for pound, it contains two thirds the heat value of coal. While our coal resources seem to be failing, science may find a way of growing vegetable fuel fast enough to meet all requirements. Last year’s corn crop, it is claimed, would meet fuel require- ments of all industrial plants in the United States for about six months. |

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BR MERLE. Tidy Popular Science M. onthly How Scientists Are Taking the Pinch Out of America’s Billion-Dollar Shoe Bill New Tanning Discoveries Will Bring You Cheaper Footwear a

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If a giant cobbler should work into one big shoe all the leather that American men, women, and children are wear- ing to-day in the form of foot- gear, the shoe would cover the entire island of Cuba SOUTH AMSIISFy oo <i so By John Walker Harrington

MONTHLY. family’s expenses for footwear.

* WELL-SHOD feet are among the essentials of health and long life,’’ declared Dr. John B. Huber in a recent article in POPULAR SCIENCE The magnitude of our national shoe bill is re- vealed in this story of new discoveries in tanning, which hold forth hope of a coming fall in every

HE expense of keeping the feet of 4 eo American people off the ground has been so high since leather went to war that every shoe pinches a pocket-book. The enormous cost of keeping us shod may be comprehended when we consider that according to the last available census of manufactures, $1,149,560,000 worth of boots and shoes are produced annually in the United States. In fact, this sum nearly equals the cost of providing our daily bread; for the value of wheat flour made annually in the United States, according to the same census, was $1,436,388,000, or only about $300,000 more than the sum at which the boots and shoes were appraised. New Discoveries in Tanning Science, however, is now at work to slice America’s shoe bill. In the chemical laboratory. and in the machine-shop speedy processes of tanning leather are being substituted for the slow and ex- pensive methods handed down through generations. New materials that can be made available for footwear are being dis- covered and developed. As a result, there is substantial hope that new, improved processes will help to cut at least 25 per cent from the cost of shoes, saving $287,- 390,000 annually. ‘ If all the boots and shoes worn by the men were placed end to end, allowing 12 inches as the length of each, they would reach four times around the earth and still there would be enough left to keep a few regiments on a war footing. Suppose that some giant cobbler should work all the leather used in all the footgear of the men, women, and children of this country into one big shoe! He would need the entire 800 square miles of the island of Cuba on which to put it. This would not, of course, include the slippers and the babies’ shoes, so he would have to save the island of Manhattan in the center of New York for the infant size. Some of the younger generation wear cloth and fiber shoes, of which 8,000,000 pairs are made a year, but in the main the hides of the ox and the bull, the skin of calves and of kids is used in the manufacture of footgear. The day is not far distant when the shark and the porpoise, or the white whale, will yield a far larger percentage of their hides to the tannery than they do at present. As science takes a still deeper in- terest in our shoes, many more kinds of skins and hides will be made avail- able for our wear. Indeed, the time may come when we shall be satisfied with mashed paper heels and when rubber will be adapted to all kinds of weather. Looking into the future, there is much hope for less costly footgear in the many new processes for tanning leather quickly that are now being perfected by up-to-date chemistry. Of all the trades, that of tanning leather seems to have been about the last to come under the control of science. Every commercial variety of skin

or hide has to be prepared in some way before it can be used for human wear. The pelts of animals, when removed, will dry up or become hard, or even rot, unless they are prepared to withstand decay. Tanning is the chemical process that pre- serves them, makes them comfortable to the human foot, and keeps out moisture. When a hide has been tanned, it has under- How the Laboratory Is Cutting Your Shoe Bills

This is America’s annual shoe bill. 25 Through labora- tory methods of tanning leather, chemists hope to aid in reducing the cost at least 25 per cent = \ $1,149,560,000

Popular Science Monthly

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ay ar. vill ess Ly. re- re. eT~ o a’s Hl. i. of or, to ng ist March, 1922 gone certain changes in its fibers that make it a new product. Chemistry has waved its magic wand over it, and has made it new. Despite this fact, however, chemis- try has had little to say about tan- ning until the past few years. In the past, the formulae for making the tanning liquors have been handed down from father to son. If hides have been spoiled, the moon has been to blame and the public has paid for the damage. Old Methods Are Costly What a hard working citizen is the old time tanner, in his rubber boots and his stained apron! As stubborn as the blind mule that grinds the bark for the vats, he wades around in tons of wet bark and hauls away at the dripping hides for months before he is ready to say that he has made leather. Even in some of the most up to date tan- neries, from three to six months is required to prepare a hide for the shoemaker. All this is tremendously expensive. With the new methods, it is possible to tan some hides in 24 hours, and the quality of the goods is as high, and even higher, than it was before science lent a hand in leather manufacture. The college pro- fessor has been leading the leather industry into ways of economy by employing sub- stances that will work the chemical changes of tanning quickly. It took the college professors in the grea leather school at the University of Leeds, England, to show the tanner how he could save time and money. Within the past few years, the American scientists have been coming to the fore, as was shown by the arrival of many delegates from England to attend recent meetings of the Section of Leather Chemistry of the American Chem- ical Society held at Columbia University, New York City. Certain manufacturers have created a substantial fund for the investigation of the facts of chemistry that apply to tanning, and have placed the reports of those re- searches at the disposal of their com- petitors. Part of the fund is used at Columbia by Professor Arthur W. Thomas in running the smallest tannery on earth, which occupies only a square yard. Small bits of hide are in this tiny plant put through all the processes of the big estab- lishment, and their structure is studied under the microscope. At Pratt Institute, in Brooklyn, is another center of the new tanning art, where up-to-the-minute tan- ners are pupils. Exact Knowledge for the Tanner One of the new wrinkles in the tanning of skins is the gaging of tanning materials by the electrical discharges that come from them. This process gives to the tanner an exact knowledge of the work that his ma- terials will accomplish. By studying the nature of the structure of the hides more closely in the light of the new knowledge of the colloids, that is of substances similar to gelatine, the tanner of the new school has his material tested in advance, so that he can tell just how it will act, instead of depending upon mere luck. The modern tanner obtains extracts of his vegetable tanning ingredients, instead of making use of the substances themselves. He has learned, too, that the astringent action is due to tannin, its active principle, and that the making of the astringency is af. ..RUCUTANNDN Fleshing and glazing machines in modern Amer- ican tanneries are replacing the old method of removing the flesh from hide and skins by hand connected with the electrical charge of those tannin particles. The higher the charge, the greater the astringency. As a result of such discoveries, blind use of cer- tain vegetable extracts is no longer neces- sary, since the properties peculiar to one kind can be obtained from an entirely dif- ferent extract by simple treatment, accord- ing to the principles of colloid chemistry.” One of the most difficult problems in tanning is known as the regulation of bat- ing. When hides are soaked in lime and water for the purpose cf removing the hair, they swell, and must be reduced to normal, otherwise they’ will have a soft texture which will make them unfit for good leather. They are reduced by the bating process, which consists of soaking them in a “pickling” solution. Formerly this process was so uncontrolled, that many valuable hides were spoiled in the bating. By means of the microscope and the hydro- Sah nw Tey: Wr .: "2 ‘aes Pot 2G ‘a JERSEY “> a CITY , a oz St; r wie 57 gen electrode, the nature of the action of the bating liquors has been estab- lished and a method devised for managing and directing the process that has changed it from the most mysterious to the most scientific process in the tannery. Hides Tanned in Eight Hours The leather chemist of the present day advocates the chrome process of tanning, where speed is desired. This consists in submitting the structure of the hide to certain chemical changes, by adding bichromate or potash or such substances to the vat liquors. By this method, hides have tanned within eight hours. For many purposes, the chrome leathers are preferred. Certainly they are made in a manner that does not keep the money of the tanner tied up in his vats. In the opinion of the leather chemists, the whole art ~* tanning is likely to undergo stil more radicai changes in the next few years. Through such described shortening of schedules, this revolutionary move will make its influence felt at the cobbler’s bench and in the retail store so that the American public may have better and at the same time cheaper shoes. The leather in all the foot- wear worn by the babies and young folks in America would make a single shoe large enough to cover Man- hattan Island es ae ee

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Nest-building material, such as bits of wool, cot- ton yarn, and feathers, offered to the birds in a screened box, will induce them to nest near by BACK WASH

OUTLET TO HOUSEHOLD SUPPLY Hard water is unsuited for household purposes and must be softened before it can be used. The filter shown above is connected with the supply pipes

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Popular Science Monthly One of These Household Brighteners Is Just What Your Home Needs

Here is a small electric range, supplied with current from an ordinary light socket. By careful management a full meal for five persons may be cooked on this range in a short time and economically

The new juice filter shown above stands solidly on its own legs and may be folded up when not in use STEAM ouner) OF THERMOSTAT

When the boiling point is reached in this com- bined electric stove and fireless cooker, the steam causes the thermostat to cut cff the current

The handle of the serv- ing fork illustrated above is equipped with a sliding pusher that discharges food from fork if the thumb is pressed against it When you pull the trigger of this pistol gas lighter, a burred steel wheel at the muzzle rotates against a small flint, and the sparks light the gas

Fruits or vegetables placed in the conical colander are pressed to pulp by a wooden plunger and forced through the holes of the sieve

An electric heater (on the left) may be changed to a miniature baking oven by the use of a removable attachment (on the right), which takes the place of the orna- mental top of the heater

A convenient attachment to the kitchen table is this sanitary catch-all, which may be lined with a double thickness of news- paper folded like a pocket « Popular Science Monthly

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March, 1922 New Birdlike Wings for Airplane Save Power 5 glertaaggsces tests of a new form of airplane wing modeled after the wings of soaring birds may result in radical changes in airplane design in the future. This prediction is generally made following a recent demonstration of the “Alula” wing, illustrated and described in PoPpu- LAR SCIENCE MONTHLY for February, 1921. In the test flight the trial airplane reached a height of 3000 feet in 72 seconds—demonstrating the excellent lift of the wings. These resemble those of a bird both in outline and cross-section, as each is arched at the center and tapers away to a point at the tips. In the ordinary airplane wing there is considerable loss of power and lift due to inefficiency at the tips, but the new model is said to utilize the entire lifting surface efficiently. The wing has a surface of single-ply mahogany built on ribs, with stretcher pieces lying between the ribs. Because of the vary- ing curvature of the wing, spars of the usual type are impossible. Compare this statue of the famous sire of the Morgan breed with his descendants in the upper illustration Statue Built in Memory of Famous Horse A STATUE in memory of Justin Morgan, the famous horse that founded the breed bearing his name, was erected recently at the govern- ment’s Morgan Horse Farm, at Middlebury, Ver- mont, where Justin’s descendants are still pre- serving his noteworthy traits after 20 generations. Justin Morgan was foaled in 1789. In endur- ance and general utility he was one of the world’s great horses, and his descendants were in uni- versal demand when endurance was more to be desired than speed. The characteristics of the breed have been maintained for over 200 years. The short back, long, oblique hip and shoulder blades, and the exceedingly broad and muscular loins, which were the outstanding points of Justin Morgan, have been con- served in his descendants. Castor the sturdiest descendant, in a recent United States mounted service endurance test of 300 miles in five days, placed fourth among 17 entries. wo warm sunshine and spring rains begin to melt the snow cover- ing certain slopes of the South American Andes, a mysterious congregation of white-robed kneeling penitents assem- bles. For some inexplicable reason, the snow in this locality melts in pointed, triangular shapes that from afar closely of rocks and earth. Melting Snow Forms Congregation of “Kneeling Penitents” resemble women with white shawls over their heads, kneeling in prayer. This formation may possibly be due to the nature of the ground, which is a mixture If the snow over the stones melted faster during the winter, so that the alternate freezing and thawing gradually changed it to a pillar of ice, the Melting into strange, triangular shapes, the snow in the Andes appears from a distance to be a host of mysteri- ous, white robed beings kneeling in prayer on the mountain slope. The exact manner in which these figures are carved by nature remains unexplained heat and rains of spring would wash away the softer snow from around these columns and so carve the ‘kneeling penitents,”’ or ‘‘nieve penitente.” Or, the mystery may be explained by the fact that snow, falling on rocks cov- ered with an insulating layer of lichen, will remain unmelted a long time. snganD ar....2

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Popular Science Monthly OME blizzardy morning, if you live in a big city, you may look out of your window to see a monster motor- driven snow shovel creeping down the street, pushing its nose into high drifts, shoveling up snow at one end, and turn- ing it out in the form of tightly packed snowballs at the other! Or perhaps you may see a great whir- ring rotary plow, scooping up deep drifts and shooting out the loose snow through a funnel to the side of the street. Machines such as these, proposed at a recent meeting of the country’s foremost mechanical engineers, are designed to meet the problem of snow removal in large cities—now an out-and-out engi- neering problem. In particular, the ex- perience of New York City with several heavy snowfalls has proved that it is better to depend upon mechanical equip- ment than upon a hastily recruited force of ill-clad and inefficient men. The aim of the snow-removal en- gineer is to sweep the streets clean be- fore the snow can freeze into ice, and to pack it densely so that the trucks may carry full weight as well as capacity volume. The machine proposed by Mark A. Guigou, of New York City, is oko OO —— \— - ar war EXHAUST ee ts. ee edie = Noted Engineers Design Powerful New inewtigning Machines Drifts scooped up by the whirring wheel of the proposed rotary snow plow are shot from a pipe to the side of the road primarily a snow compressor, with which snow may be packed into a quarter or an eighth of its original volume. A scraper rests on the street, and as the machine a ac ENGINE — by > ° ; “ey _ - 9 ~ ST ew . ogg Revolving paddle compressors in this shoveling tine pack the snow into solid cakes after it is forced up an incline conveyor RACKS a7 plunges into the drifts the snow is forced onto a conveyor belt that car- ries it up an incline and drops it into a packer. Here the snow is compressed between broad paddles, placed at right angles on two parallel axles. These turn in opposite directions. The com- pressed snow drops onto a screw con- veyor that discharges it in solid cakes which can be quickly handled and loaded into trucks. For deeper snow, D. L. Ellis, of Seattle, Wash., favored a gas electric rotary snow plow that will pick up the snow and shoot it either in a long pile at the side of the street or drop it directly into a truck. Therotor of this machine is a large wheel with cutting teeth and scoop edges. The loose snow is thrown off through a pipe which can be aimed to the side or downward. The machine runs on an endless tread, and derives its power from two 142-horsepower gaso- line motors direct coupled to a 70- kilowatt generating set. What Time Is It Now in the World’s Big Cities? A SET of clocks that tells at a glance what time it is in London, Chicago, San Francisco, and Yokohama is the latest device of a New York merchant to attract shop-window attention. Looking at the clocks when it is three minutes before four in the afternoon in New York, one sees that it is three min- utes of three o’clock in Chicago, three minutes of one in San Francisco, and three minutes of nine in the evening in London. Far away in Japan the fishermen are looking through early morning mists, for it is six A.M. of tomorrow in Yokohama. Somewhere in the Atlantic ocean east of New York is the twilight of sunset, and west of Japan is the twilight of dawn. THE efficiency of energy transmission by radio is virtually nil. The approximate ratio of radiated power to received power in transoceaniec communication is one hun- dred trillions to one. Five clocks tell the world’s time “Ultra-Microbes” Attack and Eat Disease Germs LTRA-MICROBES which prey on the germs of typhoid fever, dysentery, and bubonic plague are said to have been dis- covered by Dr. F. d’Herelle of the Pasteur Institute, Paris, who believes this new organism will help to check future epidem- ics. He claims to have made men, animals, and birds resistant to disease by introduc- ing into their veins microbes that feed upon the disease germs. All that would be necessary to check an epidemic like typhoid, Dr. d’Herelle is re- ported to have declared, would be to pour a small number of the ultra-microbes into the water reservoirs of a city. The ultra- microbe is tasteless and absolutely harm- less to mankind and to all domesticated animals, as it will not injure the white corpuscles of the blood, he says. The Paris doctor has named his parasitic ultra-microbe the “bacteriophage.” a Ponular Science Manil?..

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March, 1922. Survey of Snow Forecasts Next Season’s Fruit Crop gale a this winter on the Rocky Mountains has a direct influence on the price of cantaloups in New York City nextsummer. For on the snowfall depends the amount of water that will be available for irrigating Western farms, and the prod- uce sent to market will vary almost * directly as the water supply. So, the more snow, the more fruit. Snow survey is undertaken to learn as far as possible in advance how much water will ‘be collected in the irrigation dams. Surveyors travel into the water- sheds with indicating poles, which they thrust into the drifts. An aluminum spring balance with an adjustable index on the sampler gives the water content of the snow without computation, while Weather Bureau records indicate the depth of the fall. This is checked by measuring the depth of the drifts, and thus fairly accu- rate forecasts of the probable water supply for the coming season are obtained. By thrusting a long indicating pole into snowdrifts at various points, the surveyor determines the depth of the fall and hence the water content of the snow 61 CONDUITFOR = ae INELATING-DAM wit The huge canvas tube, filled with water, conforms to the river bed while the stream backs up behind it. At the right is the filler hose Portable Canvas Tube Dams Shallow Stream HENEVER it is desirable to erect a temporary watertight structure quickly and cheaply, the portable canvas dam invented by Johan Stire, a Norwegian engineer, will meet the need. The dam consists of a large canvas tube seven feet in diameter which is anchored in place across the bed of a stream and then pumped full of water. The weight of the gigantic hose makes it conform to irregular- ities of the bottom. The canvas is protected from the cutting action of sharp stones by an enclosing network of tarred rope. During erection, one end of the tube is closed with a grip of beams with intermedi- ate packing. The other end is placed on the river bank and the filling is accomplished in about 20 minutes through a small canvas hose led upstream. The inventor spent seven years perfect- ing the dam, which is in use in many parts of the world. It may be used as a cheap permanent dam by pumping the canvas tube full of liquid concrete. Motor Driven Grader Shaves Roads Quickly "TRIMMING the subgrade of roads as smooth as a floor and true to grade, a new motor-operated grader that drags itself along the road by cables and works on the principle of the lathe milling cutter, promises economy and quick work in road- making operations. One man is in entire control of the machine. The trimmer moves along the tops of rails built at the roadside, or upon the side forms placed to retain the concrete. It consists of a large roller carrying a series of four-foot digging buckets, equipped with removable steel plow lips, set to drive in five different places to depths varying from two to four inches. T'wo plows shave off the sides between the forms and the buckets, and the buckets trim the road. The excavated material is held in- |! side the bucket lips until the buckets revolve to the top of the roller, when the earth, dropping out by gravity, falls on a conveyor belt running through the center of the roller and is carried to the ditch at the side of the road. The cutting depth is easily ad- justed by means of hand-wheels on both sides of the machine. The same gasoline motor that runs the cutting mechanism also turns two sheaves. These haul in two wire cables leading down the road, and so propel the cutters forward. The sheaves are operated by worm gears in order to make the movement of the machine steady and powerful. On the average Haulin itself ‘along on rails, the machine trims the subgrade smoothly and discharges the excavated material at the roadsides. A concreting machine follows close behind es WHEELS FOR ADJ ~~ OFPTH OF Cb USTING Rotating buckets with sharp li dig into the road, then drop t earth onto a conveyor belt that dumps it at the side road, the feed is three and one half feet a minute. Contractors report that this machine has often dug up stones three and four inches in diameter, and that after one passage over the road the subgrade is ready for the application of concrete. As the cutting lips overlap, there are no ridges to be removed by hand.

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4 4 4 ; ’ Will water freeze in a vacuum?—J. C. T. Yes, because as the pressure is dimin- ished, the water will boil at lower and lower temperatures, and at the same time the temperature of the liquid will fall rapidly until finally, when the pres- sure approaches zero, the water will freeze. How Copper Is Hardened Is copper hardening considered one of the lost arts?—A. L. M No. There are several known methods of hardening copper, the most common being to combine with it a small quantity of cuprous oxide. The metal is also hardened by mechanical working. Rifle Caliber Defined What is meant by the phrase, ‘‘caliber of a rifle’? ?—T. S. The caliber of a rifle is defined as the exact measurement of the diameter of a cylinder which, bearing on the “lands,” can be inserted -in the bore of a gun. That is, a .22 caliber rifle has a bore which measures .22 inches in diameter from “land” to “land.” The Reason for Twilight What causes twilight and what makes it disappear so suddenly?—E. B. L. Twilight is made possible by the earth’s atmosphere and its power to refract the sun’s rays. For a certain time after the sun has disappeared below the horizon the sun’s rays pass through the earth’s atmosphere at such an angle that the particles in the air reflect and refract the light rays onto the earth. A few minutes later the sun will have sunk so low be- yond the horizon that its rays pass out of the atmosphere and are not reflected. === PARADOXES OF SCIENCE == Water Runs Uphill brilliant. Now place over the new amalgam a sheet of smooth writing paper and on it pile books of similar weights. Leave it overnight. The amount of weight needed is not great— just sufficient to keep the new amalgam in close contact with the glass. The amount of mercury should correspond as nearly as possible to three drams to the square foot of surface to be resilvered. OU know, of course, how the ordinary siphon works, but do you know how to make a self-starting siphon in which the water apparently starts to run uphill of its own accord? In the illustration below we show a self-starting siphon. When the tube arrangement is lowered into the jar, water rushes in at the two openings in the lower rubber stopper. The air is pushed out by way of A. But the water that passes up the small nozzle from the center opening gets pushed in by the rush of air and the result is a bubble of air and a bubble of water all along the tube as shown in the diagram. Now consider point A. Acting downward on it there is the combined weight of all the air bubbles and all the water bubbles. What is meant by white gold? What, actually, is meant by ‘18 karat’’ or ‘14 karat”’ gold ?—J. P. I. Solid gold is considered as being 24 karat. Therefore, 18 karat gold is gold containing six parts of other metals. The color of gold objects depends on the metals that are mixed with it. Thus if silver is melted with gold, the result is a light, almost white, gold. If copper is added to the pure gold, the product is known as “red gold.” The exact formula of so called “white gold”’ is a trade secret. Blotting Paper Substitute How can I make the white plaster forms that are now frequently used in place of blotting paper?—M. O. A solid substitute for blotting paper can be prepared by mixing 14 parts by weight of plaster of Paris and two parts of potato flour with sufficient water to produce a plaster paste. Pour or press into a suit- able mold. When dry, the surface makes an admirable blotter. How to Cement Celluloid What can be used to cement two celluloid articles?—F. A. The collodion solution sold commercially under a well known trade name will be found effective as a celluloid cement. Another cement can be prepared by mix- ing the following ingredients: Camphor, one part; alcohol, four parts; dissolve and add an equal quantity, by weight, of shellac. The Sources of Radium What are the principal ores from which radium is extracted? What is the life of radium?—N. I. G. Pitchblende, carnotite, and autunite are the principal sources of radium. The i | 62 Popular Science Monthly Ma What Do You ! Want to Know ? Let Popular Science Monthly Answer Your Problems Water Boils, then Freezes chamois rub the foil until it becomes The Color of Gold S But acting up- ward on it there is the weight ofa column of water Sun Appears Before It’s Up radiating period of radium is computed Is it possible to see the sun before it to he about £500 pone. rises?—A. C.S Yes, due to the refraction of the sun’s rays by the earth’s atmosphere. How to Resilver Mirror Please tell me how to resilver a mir- ror?7—D. F. G. Place the mirror face downward on a table and clean off the spot to be silvered by rubbing it with a small puff of absorb- ent cotton. Now spread over the spot a piece of tinfoil a little larger than the area to be repaired, and after spreading out smoothly let fall on the center of it a drop of metallic mercury, then with a bit of | and water column combined. The air | and water column will then move up extending from the surface to the point A marked in the drawing. Ifthe point A is low- ered far enough under water, the water column will be heavier than the air — INLET TUBE (Noe ee ne Z WATERINLET — (WITH NOZZLE) and over, gradually removing all the air from the upper tube. Thus, after a while, you have all the necessary working conditions of the usual siphon. What Is Your Question ? Every reasonable specific query in the field of general science addressed to this department will receive a prompt reply. Legal and medical queries cannot be answered. A stamped self-addressed envelope must accompany each question, but the writer’s name will not be published, if he so requests. Address the Editor, Popular Science Monthly, 225 West 39th Street, New York. Popular Science Monthly Electric Trouble-Detector 7... os FF iF _g 222 i. fF.

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ly March, 1922 68 1] 7X. _».. What Paris Has to Show | @ Us in the Line of Speedy Cycle Cars eS EEE BE (COMBINING lightness, speed and economy, the small car is becoming extremely popular. How it is establishing itself in England by re- markable speed records was graphically described in the February issue of POPULAR SCIENCE MONTHLY. On this page are the latest cycle models exhibited at the recent Paris auto show. —— “ 4 4 Gyroscopic two-wheeled cycle cars were ex- In the latest scooters from the Otobiron shops q hibited in experimental form. The gyroscope the three and a half horsepower motor is under ji is attached to the rear wheel, its effect aug- the saddle. The frame is larger and heavier : mented by a balancing force derived from the than in former models, with a more comfortable large, heavy wheels. The chassis is by Gies- seat. The pedals control brake and accelerator; f berger. Practical use for the model illus- otherwise the machine is operated from the 2 trated above may be found on the narrow hand grips like a motorcycle 3 roads of the French colonies $ The M. A. S. E. cycle car illustrated below, has a curved chassis frame, bending upward over the rear wheels to permit an improved spring attach- ment. The drive is exactly the same as that of standard auto- mobiles, and a gear shift is in- troduced in spite of the small power of the motorcycle motor propelling the car “Ye With a compact one and three quarter horse- power aviation type engine attached to the front wheel, the new Peugot motorbicycle shown above can make 20 miles an hour. The front fork is strengthened—the only change necessary ARRAS OE GE cea On the Weler cycle car the engine has been taken from the The Jacquemont cycle car is air cooled and carries a five- - : hood and mounted on a platform extending back of the rear horsepower motor cranked from the side. An unusual sus- : wheels. This greatly simplifies the transmission problem in pension of coiled springs in dustproof sleeves is utilized | the light car, but exposes the six-horsepower engine for the front wheels, reducing the unsprung weight ; — Unyeh 1999 65

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Triplane at Paris Show TRIPLANE, exhibited at the recent Paris aerial show, was pronounced a unique departure from established lines, particularly in wing arrangement. The lowest plane is the largest and the upper the smallest. The struts are so arranged that they form a system of triangular trusses that make bracing wires unnecessary. Instead of being mounted in the fuselage,

Has Novel Wing Design the engine is in a separate ‘“‘power egg” hung between the top and bottom planes. The cockpit for the pilot is in the fuselage, just behind the wings, and slightly below and to the rear of the engines. The ma- chine is a hydroplane, and an attempt seems to have been made to add to the lift of the wings by altering the conventional lines of the boat hull.

Pivoted Front Spring Relieves Strain on Truck A TRANSVERSE front spring pivoted at the center and shackled to the axle at each end has been adopted on a one-ton truck model produced by an American manufacturer to minimize frame distortion and give increased flexibility to the running gear. Rough roads strain such a chassis very little, for with spring suspension of this type a front wheel can be raised more than a foot from the ground while all other wheels rest on the road. Additional bracing for the front axle is provided by two diagonal radius rods shaped like a wishbone. The ends of the rods are attached to the axle at each side near the wheels, and the butt of the wish- bone terminates in a ball joint that fits ina socket on the under side of the transmission

Onc front wheel can be raised a foot above the other without frame distortion case. Even the bracing is perfectly flexible and will accommodate itself to an uneven road, saving truck and driver many jolts.

Tiny Violin Softens the Tone of a Phonograph MADE in the shape of a violin only for the sake cf appearance, this device modulates the tone of a phonograph directly at the point of reproduction, so that the tone is softened without being muffled by throttled openings. The attachment is clamped on to the rim of the reproducer, and works by slightly reducing the vibration of the mica dia- phragm. The tonal quality of the music is unaltered, and the sound produced can be reduced until it is safe to play a phono- graph in a city apartment after twelve at night without fear of reproaches from the police or sarcastic neighbors.

Most ‘French briar’”’ pipes actually come from Corsica. The Sicilian briar-root is considered the best.

Popular Science Monthly Electric Trouble-Detector Fits in Pocket like a Pen ESEMBLING a fountain-pen in size and shape, and readily carried in the pocket, a new trouble-detector for electric repairmen contains a polarity indicator that needs no connecting into the circuit to be tested, a compass that can be used in any position, an alternating-current de- tector, and a frequency meter, with a range equal to a standard instrument. The detector is useful in locating grounds and short circuits without cutting or dis- connecting wires. Similarly, it is adapted to quick location of faults in connections and windings of generators and motors. Noises that would interfere with devices

8 ER RT AH ye Disconnecting of wires is unnecessary with this pocket detector, which is tuned to the frequency of the current by means of an adjusting button and indicator

depending upon sound do not bother the user of the new instrument, since indica- tions are visual. The detector is a reed device operating on the resonance principle, and tuned to the frequency of the current to be detected. For this tuning an adjusting button is moved to a position indicating a frequency slightly above the supposed frequency of the current tested and then moved forward slowly until a red ring moves forward with a positive movement characteristic of the alternating current. The button position then indicates frequency of the current.

Air Springs for the Bicycle Saddle Give Riding Comfort ch this saddle the bicyclist literally rides on air. The flexible springs be- neath the saddle are supported on two egg-

The springs of the inflated saddle are supported on two air-filled cushions shaped cushions filled with air under pres- sure. The saddle is inflated like a tire, and is made of strong fabric lined with rubber.

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—A- i eon | ie

the l1gnt Car, OUT exposes tne sia-norscpower March, 1922

pees Wine-Cask Will Be Sold as Old Lumber ROHIBITION is responsible for the recent decision to sell the largest wine- cask in the United States, a monster wooden storage vat once one of the “sights” of Toledo. The cask used to hold several hundred barrels of wine, and when first built cost more than $4000. Its size necessitated the erection of a special building to cover it. As no use can now be found for either cask or building, both have been abandoned and will be sold as old lumber.

PoIsON baits are effective against wolves, even old and wise ones, says the Depart- ment of Agriculture. The general im- pression that wolves cannot be poisoned is declared to be erroneous. One Man Can Handle This Steel Measuring-Tape A HOOK on the end of the tape, and an extensible lug in the case, take the place of the other man who used to be necessary when measurements were taken with a steel tape. With this invention one man does the whole job. The measurement is read under the in- dicator on the top of the case. A cam-lock retains the reading after it is taken, elimi- nating this source of error. A sharp tri- angular point like a heavy thumbtack, attached to the ring, can be hooked over the end of a board, as illustrated, or pressed into the wood. The operator walks to the other point to be measured and places the SOR CERO SEURLL WEICUID, SOULE FHL LOPE UE Week

READ ALL MEASUREMENTS UNDER INDICATOR eo oe Hook the ring gee =< at one point, carry the case to the other, then read the measurement

right-angled section of the case against it. The reading is taken at a glance. This right angle in the case also makes it possible for one man to use the tape in tak- ing interior measurements, such as the width of windows, or outside measurements, such as the height of doors. The extension in the back of the case is hooked over a door, and the tape drawn to the bottom.

Woodworkers’ Tool Resembles Dentist’s Drill

The plane attachment carries an assortment of cutters

With this power tool, boring holes is no longer a drudgery

ONSTRUCTED along the lines of a dentist’s drill, a new flexible power tool for carpenters and cabinetmakers has a universal chuck and a set of attachments that make it practically the equivalent of a well-equipped woodworking shop. An electric motor is pivoted on the bench, and provides power by belts working on two jointed arms balanced by a counterweight. The arms swing on universal joints, so that the work can be approached from any angle. By inserting a bit-stock or a screw- driver into the chuck, the carpenter can bore holes or set screws. Rough sawing, both rip and cross cut, can be turned out with two small circular saws, and an emery grinding-wheel can be employed. The most novel attachment, for such a small power unit, is a plane stock with an assortment of milling cutters that makes it possible to do power planing, dadoing and rabbetting at the bench.

Phonograph-Movie Machine Plays Tunes for Pictures A COMBINATION phonograph and motion-picture projector that plays appropriate music as the film is being shown has been invented by A. L. Edmin- son, of Los Angeles, Calif. After eight years of experiment he has combined the two machines into a cabinet slightly larger than that of the standard phonograph. The upper part contains the phonograph; the lower a motion-picture projector. The films are exhibited on a silk screen, measuring 18 by 22 inches, which is placed behind the doors of the sounding-box. It is claimed that the pictures are projected clearly enough to be seen by an audience 40 feet away. Little change has been made in the phonograph, except that the speed gov- ernor of the record also controls the rate at which the film is displayed. Similarly, an adjusting clutch starts the record and the film simultanéously. The film is placed in a fireproof magazine, passes through a fire- proof gate, over an adjusting sprocket and thence loops downward through the lens gate and back through the release sprocket. After exposure the film rewinds auto- matically. A cord and plug fit an electric- light socket for power and light, and a sys- tem of multiple mirrors gives a fairly large focal projection length in a small space. The illumination of the screen is so intense that the films can be exhibited in broad daylight.

Walking-Stick Supplies a Light for the Smoker CIGAR-LIGHT- ER in a walking- |- cane is a novelty that is being introduced in |, France. The lighter |! is operated by com- pressed air. A long steel rod at- tached to the handle and extending into the hollow of the cane car- ries a briquette of high- ly inflammable mate- rial, the chemical com- position of which is secret. When the han- dle is thrust into the cane quickly, the air compression is said to ignite the composition. The substance glows like a pocket light. It is extin- guished by thrusting back the steel tube.

——

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ARS. SRD. rea a Yee dice aden teenies inanmaancanee canit -aeemeae beanie nada mmmmneannlnaimameda manent a - . 3 “4 te “ eran vnee Dae eee $e ET Jobeal, a es Popular Science Monthly Double-Headed, Four-Eyed Calf Eats with Both Mouths OST double- headed _ calves are stuffed; but on the farm of Edd Ellis, at Arkansas City, Kans., is one so much alive that it eats with both its mouths! In fact, the animal seems to find that two heads are fully as useful as one. The body of the ealf is normal, but NOSES there are two com- plete heads, with two la JAWS ARE ¢ TWO NORMAI FUSED -~ mouths, depending upon the side from which food is pre- sented. While it sel- dom eats with both at once, it can do so, as the muscles are practically independ- ent. The definite causes of such monstrosities are not known, but it is found that in al- most all cases they are accompanied by very irregular forma- noses, two mouths, and four eyes. The two middle eyes are set in one_ socket, forming a double eye; but there are two eyeballs, quite independent, with inner surfaces in contact. These middle eyes seem to have atrophied, and the animal sees only with the two outer eyes, one on the side of each head. Since the fore- head is abnormally broad, the calf can- Courtesy Journal of Heredity So far, the calf has managed to enjoy life with two mouths, two noses, four eyes, and probably two brains not see straight ahead. During the first two weeks of the calf’s life the middle eyes seemed fairly normal. Later they began to turn white and finally became covered with a scaly layer. Each of the eyeballs has an independent movement. The animal eats with either one of its tions of the parts concerned. Even in this case, although an unusually perfect one, the fused jaws are somewhat abnormal. It is evident that the animal has two brains, but whether its movements are controlled from both in unison, or whether one of the brains has atrophied, will not be known until post-mortem examination can be made. Truck Is Lowered, Head First, Down Hundred Foot Shaft — = order to lay a cable in a tunnel being eonstructed below the East River, the New York Telephone Company recently found it necessary to lower a five-ton motor truck, head first, down a 100-foot caisson shaft. Although there was never more than three feet of clearance in the shaft, the truck reached the floor of the tunnel safely two hours after it began the descent. This unusual feat was undertaken be- cause no approaches to the tunnel had been dug, no rails were in place, and no other motive power was available for laying the cables. Delay in placing the cables until these facilities had been installed by the contractors would have meant at least a year’s delay in adequate telephone service in the suburbs. The fact that the shaft was too small to permit the truck to be lowered in a hori- zontal position, added to the difficulties of the job. While the over-all dimensions were 71% feet by 24, much of this space was occupied by air pipes, staircases, and reenforcing trusses. The truck itself was 7144 by 22 feet, so there was nothing to do but lower it, radiator first. The question was, how? A derrick with a 55-foot mast and a 70-foot boom, in use at the top of Photographs courtesy Telephone Review i A difficult moment. When the mt wheels reached the tunnel floor, a quarter turn was necessa to place the truck in position the shaft, supplied the answer. The truck was drained of gas, oil, and water; slings of wire rope were placed about the rear axle, and it was hoisted into the air and lowered like a load of earth. The greatest difficulty was encountered after the front wheels of the truck reached the floor of the tunnel. At this point it was necessary to give the truck a quarter turn before lowering it on all four proper direction. There was a space less than 11 feet wide in which to make the turn, and the clearance was measured in fractions of an inch. As soon as the truck was on the floor of the tunnel, refilled with gas and oil, the reels of cable were lowered and placed on the body. The machine then backed through the tunnel, paying out the cable wheels, so that it would = come to rest facing in the ae SE al Above—After the truck was safely in the tunnel, the reels of cable were lowered to the body. Left — The machine suspended in midair, ready for the descent behind it. After each reel was laid, work- men rolled back the empty reel ahead of the truck as it returned. With all these drawbacks the installation of 13,976 feet of cable was completed in six working hours. Without the assistance of-.the truck, the job would have been impossible. a on: a ee > 05 =~ hr Ot OCS —s

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ly Te Uy SS le C= of e ot le > a) March, 1922 67 . = Gas from Sewage Waste Runs ~~ “GENTRIFUGAL _ SLUDGE PUMP _.- ee eee City Power Plant ier yt : ee ee ed How the sewage disposal plant at Birmingham, England, supplies its own power is described in the illustration. Gas from the sewage drives an engine of 20 brake horsepower, which operates a centrifugal sludge pump gh that costs large cities tremen- dous sums each year can be turned into a source of power equivalent to thousands of tons of coal! The waste now dumped into rivers or shipped to sea may be used to run factories or to light buildings! That conversion of sewage into power is possible has been proved conclusively by the city of Birmingham, England. There a suction gas engine of 20 brake horsepower has been successfully driven by the gases given off by sewage sludge. On the basis of the Birmingham experi- ments, an American city that must now pay for the disposal of 400,000 tons of sewage sludge a year might produce 320,000,000 cubic feet of gas suitable for heat and power, or, in terms of energy, 16,000,000 horsepower hours at 20 cubic feet per brake horsepower. The apparatus for producing gas from sewage consists of two sludge digestion tanks in which the sewage is allowed to ferment. The gases given off are composed of from 25 to 75 per cent of methane, or marsh gas. A gas engine of the usual type will run on sewage gas without adjustment of the valves. Sewage gas has a higher calorific value than some illuminating gas, averag- ing about 650 thermal units to the cubic foot, as against 550. The Birmingham engine runs about six hours a day and is used to operate a centrif- ugal sludge pump that moves the wet sludge from the gas-generating tank to the drying grounds. In this process a small proportion of the waste material produces enough power to run the pumps of the sew- age disposal plant. If all the material were used, there would probably be enough gas available to light the city. No Axles nor OW comes the axle-less automobile, with the claim that it will travel over the roughest roads without jarring its passengers. Transverse springs, placed about 10 inches apart, and pivoted to vertical members that carry the wheel spindles, enable the wheels to absorb shocks and to conform to the road without trans- mitting appreciable jolts to the chassis. In tests the car has been driven at 50 miles an hour over roads that were almost impassable to the standard car traveling at 20 miles an hour. The frame, or chassis, is an integral part of the body, and is bolted solidly The upper spring is fastened to the frame; the lower to the wheel yoke Chassis Frame in New to it. Since all four wheels are virtually floating, the location of the transmission presented a problem that was solved simply by bolting the differential housing solidly to’ FRONT WHEEL SPRINGS arr ATTACHED A HERE to EER ts Ha ed ee a i Re cl a AR WHEEL beceee=e ASSEMBLY ATTACHED HERE Bolted solidly to the body, the chassis ; omes part of it. To the frame are bolted the springs and the differential housing. Above is the complete car Joltless Auto the frame of the car and driving the wheels by independent shafts leading therefrom. Two springs are used on each pair of wheels. The upper spring is fastened to the frame and the lower bolted to a steel yoke connecting the wheels. The springs themselves are curved into an unusual form, and it is stated that this peculiar shape, together with the elimination of the axles, greatly reduces the unsprung weight. Unsprung weight is the portion of the car not supported by the springs, and in the new model this weight apparently has been reduced to the minimum. Except for the wheels, every part of the car is protected against road shocks. Attached to the frame pivoted to members holding the spindles the springs are

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68 Popular Scrence Monthly Can You Help These Boys Divide Their Lunch? Best Solutions to Sam Loyd's Puzzles Will Win $25 HREE apprentices became involved in a dispute over their luncheon arrangements that called for the arithmetical talent of the entire shop to adjudicate. It seems that Harry and Tom were about to partake of their noontime spread, when along came John with a proposition to make it a three-handed event on equitable terms. Harry had three sandwiches and two pies, while Tom’s box yielded three sandwiches and three cakes. John had no comestibles to contribute, so it was agreed that the three should share equally in the spread and that John should pay fifteen cents for his portion. They estimated that two pies were worth three sand- wiches and that six sandwiches were worth eight cakes. Then came the puzzling debate as to how that fifteen cents should be divided between Harry and Tom.

Can You Check Up This Grindstone? WO mechanics, inventorying their stock on the eve of taking a new partner, were considering a grindstone. “Put it down at half the cost,” said one of the owners, “for I ‘ figure we have ground off half of the original bulk.” Now, if the new partner proves to be so exacting as to check up the grindstone on that basis of valuation, and finds that the circular stone has a present diameter of 15 5/7 inches, and its cen- tral hole for the shaft measures 3 1/7 inches in diameter, then what must have been the original diameter of the stone if its present bulk represents 50 per cent? Of course, that hole for the shaft means a reduction from the bulk.

$25 for the Best Answers FIRST prize of $10 will be awarded the reader who sends in the best set of correct answers and analyses covering the three problems on this page; a second prize of $5 for the next best set; and ten other prizes of $1 for the ten next best sets. Answers must be received not later than March 1, addressed to the Puzzle Editor, Popular Science Monthly, 225 West 39th St., New York, N. Y. As a special convenience to readers, answers to the February and March puzzles will be published in the May issue, and names of prize winners for these months will appear in the June issue. Thus, the answers to the February puzzles will appear one month earlier than previously announced.

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Here’s a Practical Wiring Problem T= electricians below are figuring out the best way of intro- ducing three wires into that switchbox and observing certain conditions, which are these: The wires must not cross or come in contact within the box, yet the wire that enters at opening A must connect with post A; the wire entering at opening B must connect with post B, and the wire entering at opening C must go to post C. To string the wires without crossing them or allowing them to touch appears to be rather an appalling proposition at first inspection, but it is really not so difficult if a little ingenuity be exercised; so let us mark out the routes of the three wires without violating any of the conditions.

Are You One of the Star Puzzle Fans? PU22LE solvers who are deserving of special commendation for their work in answering Sam Loyd’s No- vember brain twisters include: H. T. Shrum, og Wis.; Bessie B. Bark- ley, Kansas City, Mo.; W. R. Doyle, Aberdeen, Wash.; J. P. Owens, Graham, Texas; M. Bard, Ripon, Wis.; Orin C. Watkins, Salem, Ore.; Isabelle Swanlund, Superior, Wis.; W. S. Chapin, Muskégon Heights, Mich.; W. H. Keller, Emporia, Kans.; M. N. Quade, Urbana, Ill.; James A. Conklin. Milton, N. Y.; Edwin cane Honolulu, Hawaii; i. Larson, San José, CRE et Meredith, ctoatsville, W. Va.; O: Newton, Santa Rosa, Calif.; Herbert rom heey London, ey Stella M. Hinz, Madi- son, Wis.; J. O. Wood, Muskogee, Okla.; K. S. Patrick, Victoria, B. C.; A. J. Asmussen, Stettler, Alta.; Karl J. Elk, Quincy, Iil.; W.C. Mallette, Albany, N. Y.; John Pierson, Mel- rose Highlands, Mass.; B. J. Fenton, Oneida, N. Y.; Frank H. Broome, Jersey City, N. J.; S. Boyd Calkins, Durango, Colo.; Jack Gordon, Bridgeport, Conn.; Caroline B. Boucher, Mill- ington, N. J.; R. D. Wirt, Daytona Beach, Fla.3 Jason Crain, Ww anne. ro m.: A..K. Walton? New “< aa; S tchcock, Middletown, Conn.; A. Judd, sae: Eo; 2 naa "Rosedale, Kans.; David S Keiser, nr” Pa.; Haig Kapigian, Camden, Ns 32 H. H. Hildebrandt, Logansport, Ind.; Mrs. Ww: Hall Moss, Dayton, Chio; M. Stinehour, Mon- treal, Can.; D. C. Lyle, Baltimore, Md.; F. H. Hertzler, Reco a Pa.; L. E. Painter, Baton Rouge, La.; Arthur Peters, Grand Rapids, Mich.; H. G. Taylor, San Antonio, Texas; Leila E. Perrin, London, Ont.; Margaret Kelly, Albany, Ore.; ‘Hudson L. White, Akron, Ohio; Claude Robinson, Jefferson City, Mo.; Ernest K. Chapin, Muskegon, Mich.; Ejner Christian- sen, Santa Maria, Calif.; 7. M. Shields, Mt. Vernon, Wash.; Chas.’ W.: Harris, Tempe, Ariz.; 'O. H. Barschel, Canora, Sask.; W. J. Oliver, York, Pa.; W. H. Ply mire, Cordova, i: C. D. Murray, Indianapolis, Ind.; James Anderson, Buffalo, N. Y.; J. A. Rafferty. St. Paul, Minn.; Morgan R. Gilbert, Ney. York City: B. A. Long, Johnstown, Pa.; W. M. Rankel, ey Kans.;. T. H. MacCauley, Schenectady, N. Y.

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hly March, 1922 Concrete River Wall Poured into Portable Steel Forms i | \ | SN B* the use of a flexible system of steel forms for placing concrete under water, a great saving in time was effected in building a a concrete coffer dam at the Buffalo Terminal of the New York ARE state barge canal. The new method was developed by Frank C. | Hibbard, of Buffalo, New York. Instead of the tedious and expensive process of driving sheet piling, then pumping out the water behind it, and-erecting wooden | concrete forms, huge steel forms were prepared in units 40 feet high and 20 feet long. Each unit consisted of a rigid frame, strengthened with trusses both vertically and horizontally, from which the wooden forms for the front and back of the concrete wall were suspended and supported by means of screw-jacks. The two forms, front and back, were lowered into the water by a 60-ton derrick, and the concrete was poured under water. To make the bottom of the form conform to the irregularities of the bed rock, a lower wooden section was sawed to fit the rock bottom as its irregularities were ascertained by divers and a series of accurate soundings. Before placing the forms, the mud and silt lying above the rock bottom of the river was removed by clamshell dredges. The surface of the rock was then cleaned by divers, who played high- pressure water-jets on it until the last trace of mud was washed —_ away. Soundings were made at each corner of the form, and four adjustable posts attached to the steel framework were ™ set at the correct height by passing bolts 2 through a series of holes in the frame. A raft was next anchored in place, and a 2 second series of soundings taken with a ’ * gage pole. The depth was measured along 3 every foot of the outer surface of the forms. ' The soundings were then m transferred to the wooden st planks on the bottom of ; ; * the form by measuring ' After the mud and silt had been from the lower edge of the 4 dredged from the rock bottom >S ei: of the river, the huge steel forms steel plates and driving in were lowered by a 60-ton derrick, nails at the proper point. ._ _ as pictured above Finally, the planks were * “™ sawed along these points. ‘Well’ holes 30 inches At the left is shown one of the in diameter were left in a a = 4 — —. each section so that the frame supported by trusses, ae concrete could be tested. tically and horizontally Tree Doctor Carries Stove : : on His Calls November Puzzle Answers and Prize Winners A PORTABLE orchard stove for use by Waeen ao ie. Potedam, NY. —— Pac we the tree surgeon in treating cuts in SECOND PRIZE, FIVE DOLLARS: A. P. ect. the bark with asphaltum paint, has been ee ee eee: oe ‘ invented by Paul Livingston, rancher of Rosson, Burlington, Towa; MO, Wellman Fencing the Land . ansing, 3 Be » Berlin, Conn.; of a semicylindrical drum of shest iron, | Skit Bower Huron, So, Dak; WW. Muli, HE surveyor reduced | ith a small smokestack of iron pipe at one couver, B.C.;" P. J. Condon, Brooklyn, N. Y.; the area of his Fig. ; |4sqet ’ ™ Arthur W. Newell, Orlando, Fla.; M.S. Dechert, 4,a right angle triangle, “~~ — Ohio; Olaf T. Gylleck, Grand Haven, from 6 to the required 4 square feet, by turning in three of the rails and thus How He Patched the Roof cutting out two squares, as shown in the diagram. Also he might have arranged _ gaat the rails in the form of a parallelogram, — , OR, as shown. a Rg 7 The above arrangements of the rails io : gy as: may be somewhat varied without affect- : / - — ing the area, and all such as were cor- weg f ‘ ‘ rectly presented are given full credit in wn, ‘ —E ‘ the scoring. a i F WwW: -e FIG.1 How Far Did the Car Go? on- Shao HE _ tinsmiths N the first third of the distance around ids, — , dissected the D the automobile track, the driver went oy The tree doctor and his stove three squares and |c . at the rate of _ mile in _ yi hio: combined them to F in the second third, one mile in — a pci —— form the required [|— Sel of a minute, and in the last third, a mile Mt. to another. large square, as * B in 6/7 of a minute. It therefore follows ney The top has been flattened to provide shown in the dia- that the time -for his average mile for ova, heating surface, and hereon are placed the gram. This is from the journey was 253/273 minutes. be St pots holding the tar or wax that the a 94 2. pe im in one hour he went 64 and 188/ or orchardist wishes to melt in order to treat ee a am. ley, wounds he has detected in the bark.

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BP. eee ee ET ania Ee a ee eet a a eR irl 2 neat nti ee ee Electric Rail Bonder Drills Two Holes at Once } papery two holes simultaneously for a rail joint, a new rail bonding ma- chine that consists of four portable electric drills mounted on a handcar, has reduced the cost of bonding operations for one American railroad from $67.62 to $46.18 a mile. The work of drilling hcles in the rails for the insertion of signal bonding wires is usually performed by hand, and even efficient workmen occasionally break the expensive drills. The electric machine, run by storage batteries, drills two holes in 30 seconds. Both drills are fed by a hand- operated lever that gives the operator per- fect control and lessens the bit breakage, Hinged on a rod of the carrier, the drills are let down against the rail, or tilted back on the carrier when the car is moving while it also reduces to a minimum the necessity of sharpening the bits. On one occasion 259 joints were drilled before sharpening was necessary. A ‘41’ motor-car is used to carry the storage batteries and drill frames. There is an angle-iron bracket on the front of the car with a rod that supports the drill frames. This rod acts as a hinge, so that the drills may be let down against the rails, or tilted back on the carrier when the car is in motion. When a train approaches, slip electrical connections are instantly disconnected and the drill frames slipped off the rod and laid on the ground. The storage batteries may also be slipped off into the clear, so that only the light car remains to be lifted from the track—a task that can be performed by two men. An advantage of the electric machine over a gasoline outfit is that it makes little noise while in operation. Popular Science Monthly Pipe Cut in Many Lengths in Single Operation A MULTIPLE power-driven pipe-cutter recently perfected can cut long pipe into many short lengths in one operation. The cutters are adjustable and mounted on a horizontal shaft, the axis of which is stationary. The table located under the cutter shaft is guided by the frame of the machine for vertical movement and is raised by cams mounted on the shaft at the bottom of the machine. A special dovetail groove in the table carries a number of tube rests that can be positioned to correspond with the cutters. The steel rollers of the tube rests allow the tube to be revolved when rotary cutters The adjustable cutters are mounted on a horizontal shaft above the tube rests are used. When saws are used, the tube is held stationary on the table. A crank at the front of the machine adjusts the table height to suit the diameter of the tube and the wear of the cutters. The machine can cut tubes up to 214 inches outside diameter and wall thick- nesses up to 5/32 inch. ‘‘Side-Door Pullman’”’ Recalls Days in France A “SIDE-DOOR Pullman” almost ex- actly resembling the tiny French freight-cars marked ‘‘Hommes 40, Chevaux 8,” in which the A. E. F. traveled over France, was a feature of a veterans’ parade held recently in Los Angeles. The vehicle was three feet shorter than the car the “boys” actually used in France, but the width and height were exactly the same. Minor details were reproduced, even to the straw on the floor, the chalk marks on the door and the interior, and the inevitable flat wheel. The diminutive size of French railroad equipment was one of the first and most lasting impressions made on the Ameri- can army while in France; and the novel float was recognized as typical of French equipment by overseas men who viewed it. Analysis of Dust Reveals Danger to Miners ECENT analysis of dust in metal mines, in the course of improvements in ventilation to safeguard the health of workers, revealed the fact that the atmos- phere is often full of fine, sharp-edged particles that cut into the tissue of the lungs and may eventually cause sickness and death. Samples of the dust are collected by pumping air through a small tube filled with sugar. The tube is placed against the mine faces where the men work, and the pump is operated so as to suck in about a cubic foot of air a minute. This is the average amount breathed by a miner during his work, and the sugar collects about the same amount of dust that is retained by aman’slungs. Analysis of the samples shows whether the dust of the mine is dangerous and the probable effect of steady work on the miner’s health. Not until recently has proper ventilation been considered necessary in metal-mines. The most dangerous dust is produced from siliceous material such as quartz or flint. Silica is insoluble, and splits into pointed particles like tiny bits of broken glass. There may be from five to seventeen billion of ‘such particles inevery cubic meter of air when rock is prepared for blasting by dry drilling. The use of water in the drill holes reduces the dust about 80 per cent, but this method of working is not in general use. Many miners prefer to “eat the . dust’’ rather than take the extra trouble to protect themselves from it. we S * “ek. Sugar in the tube collects samples:- of dust when mine air is pumped through it S' yar eve hos this ple hos out del of | ple fiv the th: ins

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r i Oo 2 " ct or March, 1922 a ‘Swivel Rack for Fire Hose Saves Vital Seconds WIVEL connections for fire- hose are being installed in one large oil-storage yard in San Francisco, Calif., to save every possible second in case of fire. The hose is kept in a rack of the usual type, but this is arranged so as to swing in a com- plete circle if necessary. The connection at the top will turn with the rack, so the hose may be led out in any direction with- out the possibility of a kink forming and delaying the firefighters in turning a stream of water on the blaze. The valve for turning on the water is placed on top of the pipe, and is thus about five feet above the ground. The base of the pipe is protected by a concrete pyramid that keeps trucks from knocking down the installation. ae FROTH on stems of grass, seen in early sum- mer, is produced by an insect to protect its eggs. The insect is the ‘froghopper” (Cercopidae); nct the grasshopper. 71 AS a special service to readers, the Editor will be glad to sup- ply the names and addresses of manufacturers of devices mentioned in Popular Science Monthly. Was This the First Ship’s Orchestra in History? ECENTLY unearthed from an ancient Egyptian tomb, small clay statues of a yacht’s orchestra, with their instruments, make it possible for scientists to increase their knowledge of the boat-music of 40 centuries ago. The Egyptians believed that unless the body endured, the soul would have no dwelling or place to exist when it returned to earth, and would have to wander eter- nally asa ghost. It was for this reason that such care was taken in embalming the dead. Where it was inconvenient to make a A harpist, a flutist, and a drummer made up the ship’s orchestra in an- cient Egypt mummy, small clay obituary statues were thought to serve the same purpose. When one of these groups is found, as recently in a grave-in the vanished city of Thebes, detailed description of the dress and customs of the ancients is obtained. HEN the circus arrives in town, a novel stake-driving truck now re- places the picturesque canvasmen, with their heavy wooden mauls with which they used to hammer down the tent- stakes preliminary to raising the “big top.”” In the heydey of the horse or road circus, four canvasmen used to gather around a single peg, and striking in rotation with 10-pound mauls, bury it three feet in the earth in a few seconds. But the belt-driven hammer, operated Truck Now Drives the Stakes on Circus Day DRIVING BELT ae by the truck engine and similar in form to a small automatic pile-driver, is even quicker than these trained crews. And since seconds count when circus tents are to be erected, the stake-driver is attached permanently to the truck that carries the stakes and the tent-poles. The duties of the canvasmen are con- fined simply to throwing the stakes off the wagon, and holding them upright while the machine drives them into the ground. Cylinders Rebored without Removing Engine | peop auto cylinders in 24 hours without removing the engine from the chassis becomes possible with a machine whose inventor, L. S. Keeler, declares the work to be absolutely accurate. The ma- chine has a strong frame with three bearings supporting a boring spindle an inch and a half in diamter. This spindle runs in bronze bearings that take up all wear and keep the tool in perfect alinement with the base. The motor is electric, one quarter horsepower, and a worm gear is employed to give a steady drive. The cutter-heads are constructed with a cam adjustment so that three heads will take from two and three quarters to four and one half inches. Four cutters are in- serted opposite each other in the head in order to equalize the pressure of the cutters during the boring. The machine is adjusted over the cylinder and held in place by the bolts used to hold down the cylinder head, which fit into slots in the base. When the cutters are adjusted to the proper size, it is claimed that the cylinders are bored true, and with no variation between them. Electric Melter Saves Time and Sealing-Wax MOE speed and less waste of sealing- wax are claimed for an electric seal- ing-wax melter that drops the hot wax on the flap of an envelope ready for stamping with the die. The wax is placed in the orifice closed by the screw-cap at the left of the apparatus, and melts almost instantly when the current is switched on. When a lever with a knob is swung to one side, exactly the proper amount of wax to form a seal drops on the envelope. The device can be fitted on edge of table. Just the right amount of wax drops on the envelope rif |

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72 F irst American Radio Charts Show Nation Is Now Popular Science Monthly Blanketed by Wireless News and Music You'll Find in These Maps the Broadcasts that You Can Hear ERE is the first chance ever given the people of America to see at a glance how many important broadcasts of wireless music, news, and entertainment can now be heard in every part of the country. After securing direct reports from dealers and amateurs in all parts of the United States, and after excluding numberiess smaller stations, POPULAR SCIENCE MONTHLY has selected twenty-two points and has charted their location and “normal range’ on the accompanying radio map. One or another of these stations can, with proper equipment and favorable local con- ditions, be heard easily and regularly in 48 states of the Union. How to Find Your Program To find out what radio entertainment you may normally expect to receive in your locality, simply complete in pencil on the map the circles partially indicated by the dotted lines. With the proper receiving set, and provided atmospheric conditions are right, the chances are in favor of your hearing the stations within whose radius thus charted your particular town falls. Daily and nightly radio programs may possibly be heard over even greater dis- tances than are here indicated, but don’t forget that local conditions of all kinds may cut down the number of stations you are likely to hear in your district. In some regions you may have difficulty because of too many stations using the air at once. Before purchasing a receiving set, supple- ment the information given here by con- sulting an amateur in your neighborhood, and by requiring, if possible, a demonstra- tion of the set by the dealer. Finally, if the outfit you are using is one of the low-priced, crystal detector sets, remember to divide the distances shown on the map at least by 10, in order to get a reasonably accurate estimate of the radius in which any given station’s broadcasts may be heard by you. Having found on the map the cities con- taining radio stations that you are likely to hear in your district, you can secure from the following paragraphs definite in- formation about these stations. HE following stations in North Atlantic and New England states give extensive broadcasting service: Newark, N. J.—Westinghouse Electric & Manufacturing Co. station (WJZ). Wave length, 360 meters. Program of news and concerts every evening at 8.05. Children’s hour every Friday at 7.15 P.M. Pittsburgh, Pa.—Westinghouse station (KDKA). Wave length, 330 meters. Washington Observatory time broad- casted daily, except Sunday, at 8 P.M. Government market and New York stock reports at 8.05 p.m. Special musical program, 8.30 to 9.30 p.m. Organ recital every Sunday at 4 p.m. _ Springfield, Mass.—Westinghouse sta- tion (WBZ). Wave length, 375 meters. Concerts and musicai programs every Sunday, Monday, Wednesday, and Fri- day at 8 P.M. Medford Hillside, Mass.—American Radio and Research Corporation station (1XE). Wavelength, 350 meters. News,

How Radio Reaches You Wherever You Are pote have never before seen maps of the United States like those printed here. They are the first American radio charts. Only a few months ago, POPULAR SCIENCE MONTHLY started the pres- | ent national wireless craze going, with our already famous “‘Wake Up to Wireless!’ message, written by Armstrong Perry. The nation IS wide awake to-day. Nobody can predict how many hundreds of thou- sands of families will soon be enjoy- ing the most romantic recreation of modern times. POPULAR SCIENCE MONTHLY has compiled these pioneer radiotele- phone broadcasting charts in order to show just what vocal entertain- ment a good receiving-set can give. If you wish further information about wireless or broadcasting sta- tions, write to the Question and Answer Department of POopPpuLAR SCIENCE MONTHLY.

concerts, and music every weekday even- ing, with sermons every Sunday. Hartford, Conn.—Station of C. D, Tuska Co. (WQB), with a wave length of 425 meters. Concerts on Tuesdays, Thursdays, and Saturday evenings. Union College, Schenectady, N. Y.— Irregular program of music. Roselle Park, N. J.—Station of the Radio Corporation of America (WDY), Range 1000 miles. N the Southern section these stations, among others, are audible: Washington, D. C.—Government and private stations. Correct time broad- casted at noon and 10 P.M. daily from Arlington Navy Station (NAA) with a wave length of 2650 meters. The White & Boyer station, on Tuesdays and Fri- days from 7.30 to 9.30 P.M., broadcasts concerts as well as short lectures on radio. Atlanta, Ga.—Carter Electric Co. sta- tion (4CD). Range 200 miles. Musie and news service Sundays, Tuesdays, and Thursdays, from 7.30 to 8 P.M. Dallas, Texas.—Police and fire depart- ment station (WRR). Wave length, 450 meters. Weather forecast, local news, and other information at 7.30 toy daily. Concerts every evening, 8.30 to 9. Austin, Texras.—State University sta- tion (5ZU). Wave length, 375 meters. Results of athletic contests, local news. Houston, Texas.—Numerous amateur radiotelephone broadcasting stations with ranges up to 60 miles.

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To learn what wireless broadcasting stations you may expect to hear, complete on this map the circles partially indicated by dotted lines, using d ividers. Nor- mally you should hear from cities within whose radius, thus found, you live

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hly L of ys, the Y). ns, nd 1d- om ‘a ite Ti- sts on ta- sic nd rt- th, cal 30 ta- rs. VS. ur ns Nh March, 1922 f WORE than 70,000,000 people live in the portion of the United States which is shown on this map to be almost confusingly crisscrossed by new broadcasting J stations which furnish entertaining news and concerts by wireless to all who choose to hear. ne WS. MADISON fa ‘THE solid black, crossed circles on the maps in- dicate cities having flour- ishing broadcast stations working on not quite so large a scale as the others. These cities are: Buffalo, N. Y., Cleveland, Akron, Columbus and Hamilton, Ohio; Detroit, Mich.; Davenport and IowaCity, Ia.; Philadelphia, Pa.; Rome, Ga., and Paris, Tex. eee PNT 100 ISO 200 250 300 4#SO One or more of the radio broadcasting stations indicated by the circles on the map can be heard regularly, with adequate equipment and favorable local conditions, in 48 states of the Union. Find on this map the cities within whose radius you \ K 7 ORKING westward on the map, the f ollowing are the most important stations generally heard by amateurs who have reported: Westinghouse Station at Chicago, IIl. (KVW). Wave length, 360 meters. Grand opera program every evening ex- cept Friday and Sunday during opera season. Concerts Friday evening. Cincinnati, Ohio.—Station of Preci- sion Equipment Co. (8XB). Wave length, 375 meters. All evening on Monday, Wednesday, and Saturday— music, vaudeville, and sport reports. Madison, Wis.—State University sta- tion (9XM). Weather reports in code and then in voice, daily except Sunday at 12.35 p.M., with a wave length of 375 meters. On Fridays, special music at 7.30 of these stations. P.M., at 800 meters. Same music at 8.15 at 375 meters. Various entertainments dur- ing remaining part of evenings at wave lengths between 330 and 375 meters. Lincoln, Nebr.—State University sta- tion (9YY). Has widest range in that section. Concerts every evening. Kansas City, Mo.—Station of the Western Radio Co. (9XAB). Market reports and weather forecasts at 11.30 A.M. and 2 P.M., on 375 meters: Con- certs in the evening. Denver, Col.—Station of the Reynolds Radio Company (9ZAF). News twice a day. Concerts on Sunday evening. San Francisco, Calif.—Concerts by various commercial and hotel stations every evening in the week. California Theater to broadcast performances nightly at 360 meters. are; then refer to the article for details as to the posers Completing the dotted lines wil the reported ‘‘normal range’’ of these stations, but sometimes they cannot be heard for reasons given on page 72 give you Los Angeles, Calif.—Station in Ham- burger’s department-store. Reported range, 1000 miles. San José, Calif.—Harrold Labora- tories station. Range, up to 500 miles. Seatile, Wash.—Seattle Post Intelli- gencer (newspaper). Range, 60 miles. N addition to the foregoing stations there are’thousands of private and ama- teur stations scattered throughout every state having ranges up to 50 miles. Stations in Detroit, Mich., Cleveland and Akron, Ohio, and Davenport, Iowa, while less powerful than many of the others men- tioned, have transmitting radii great enough in extent to enable thousands of listeners in their vicinity to enjoy the daily news reports and regular evening concerts,

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Penida s ne carats iti tra a ane ait Fopular Science Monthly “How I Keep Down Motor Car Expenses” Readers, in Prize Winning Letters, Tell from Experience How YOU Can OU have all seen the motcr- ist who has that uncanny faculty of always having his By F. A. Cuffe, New York City Winner of the First Prize Cut Fuel and Repair Costs to Save Dollars the air spaces between the cells of the radiator. I remove this mud and tightly wedged stones car ready when it is wanted. He is the fellow who really enjoys motoring. I have merely stolen his method of working, which amounts to this—the man who anticipates trouble is better off than the man who simply remedies it after it occurs. The following ideas will show you why my car is ready to go on a long trip any day of the year. The first place to look for fuel wastes is at the carburetor. I adjust the carburetor to give the leanest possible mixture consistent with satisfactory operation. Examine All Cells Again, if the ignition system is not right, fuel will be wasted. Many a driver decides that his battery doesn’t need additional water after he has examined the first cell he happens to lcok into. But I examine all the cells, for it very often happens that one cell will be in bad con- dition or that it may be cracked so that it will require more water than the rest. And after cleaning and adjusting the spark plugs I use a jeweler’s eyeglass to inspect the porce- lains for elusive cracks that oo TTS “RECORD OF . PISTONS KEPT ADUYST THE CARBURETOR‘ a (RUNNINGBOARD 4 ; "KEEP TIRES OUT OF. OIL_ON FLOOR Car Kindness Means Dollar Saving “youD treat a horse well, wouldn’t you? “Why, then, should not the same condition exist between a man and his automobile? “Who shall say that a properly cared for, a properly loved automobile may not have some- thing that is akin to intelligence? “Car kindness means car service, and car service means dollar saving.” eo; Sf ns eS? VALVES AND™ = GROUND ETC SO a: by directing the stream of my hose through the cells from the inside. To clean the inside of the radiator of rust and deposits, I pour through a hot solution of soda and water, instead of scraping. I have found that by remov- ing stained and dirty running boards the covering can be made to look like new simply by wiping with a clean rag sat- urated with kerosene. Floor boards also can be cleaned in this way. Car Is a Friend My friend next door invari- ably greets his car when he opens his garage door with— ‘Well, how are you this morn- ing, old boy?’ Somehow the spirit of that man gets into his car, for he has the least trouble with wear and tear. Car kind- ness means car service and car service means dollar saving. often escape unnoticed with the naked eye. The valve system must also be carefully watched or it will be a prolific source of fuel waste when the valves are not seating properly. The only way to make sure about tire mileage is to record it. I do this on a card or a slip of paper or write on the wall of the garage. When I put on a tire, I set down its number and the mileage record when it goes into service. If it comes off for a time, I make a record of the mileage’ to date anda new record when it goes on again. I keep the rubber hose connection be- tween the radiator and the cylinder jacket outlet and the pump connections covered with shellac to keep them waterproof and impervious to oil and grease. I never let the tires stand in pools of oil on_the garage floor. Oil rots the rubber. Often mud and small stones will get into *‘After cleaning and adjusting the spark plugs, I use a jeweler’s eyeglass to inspect the porcelains for cracks’’ “{ Allow No One but Myself to Work on My Car” [ UBING the ten years that I have been driving cars my costs have been only for tires, gasoline, oil, grease, distilled water, polishes, and painting. I have always driven these cars myself and allow no one else to do any work on them. I believe that this freedom from trouble and expense is due to giving attention to the following vital factors: 1. Ignition, start- ing, and lighting. 2. Carburetion. 3. Lu- brication. 4. Tires. To keep down expenses on the first item, I inspect the ignition system daily, with especial care of the interrupter and distrib- utor, making sure that all connections are tight. Every month I clean and set the spark plugs. On the starting system I check up the battery every two weeks, filling with distilled water if necessary, By W. B. Bennett, Honesdale, Pa. Winner of the Second Prize tighten battery supports and all connec- tions, inspect battery wires to the starter and to the frame ground and see that the commutator on the starting motor is clean and not cutting. On the lighting system, I check up all connections once a month, making sure that the ‘cutout’? works properly and does not stick. It is especially important that wires and connections ex- posed to the weather be looked after. I have avoided a lot of trouble by equip- ping my cars with carburetors of a certain non-adjustable type. Every three months, I clean the gas tank and the line, look over the vacuum feed and the float needle valve. I drain the carburetor about once a week. Lubrication I consider to be the most im- portant of all items to keep down car main- tenance. Every morning I lubricate the ignition system, and every day I give a slight turn to every chassis grease cup. I give a few drops of oil here and there where needed, especially the spring leaves. Every 1000 miles I change the crank- case oil, and every three months I change the transmission and differential. In caring for tires, I check inflation every day. Temperature changes make a lot of difference. I even sometimes let out a little air on a very hot day to lower the tire pres- sure due to heat expansion. And I havea little vuleanizer with which I repair all small cuts before they cause trouble. 5 d a F t C I k I 1 i 1 -_ ie sae 2 ee

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he ll March, 1922 75 > —_ drive an automobile economically, the driver should be slightly what is commonly known as ‘tight.’ He must hesitate—-and it must hurt—every time he spends a dollar; for if it doesn’t hurt, costs. he will spend many dollars without wondering how they could have been saved. To save, one must think about Hence the ‘close man’ will think more about his car.’’—R. A. Houston. A Real Desire to Save Must Come First By R. A. Houston Honorable Mention HERE are three absolute requisites to driving an automobile economically. The driver must have a fair idea of the physics of an automobile motor and chassis, since it is impossible to understand action and results without understanding the -undamental causes; he should be at least an amateur mechanic in order to make his own smail repairs, and, last, he should be slightly what is commonly known as “tight.” Unless he has this last qualification, the other two are of slight importance in economical operation. To save, one must think, and thinking, in many cases, is such, a task that it must be forced; hence the “‘elose’’ man will think much more about the cost of his car than the easy spender. Last spring I won a county wide gasoline consumption contest covering a period of two weeks and for a minimum distance of 500 miles. I used ordinary gasoline, and during the two weeks I increased my mile- age to the gallon by one fourth. My first preparation for this contest was to see that the car was in good shape, that the brakes did not drag, that the valves were seating properly, that the motor was clean of car- bon, the muffler clean and that there was no back pressure on the motor. I oiled every working part and adjusted the wheel bear- ings, and last of all I pumped the tires to their required pressure. Those two weeks, while I drove, I thought always about gasoline. I never stopped behind a street car without turning off the motor, and I took advantage of every incline to use the clutch. When I wanted to stop, I turned off the motor several rods ahead of the stopping place. Now I do most of these things automatic- ally and my gas consumption is less than that of most of my friends who drive cars like mine. If you want good mileage, you have to go after it. It takes more than a lean mixture in your carburetor. It takes a desire strong enough to make you do the things that will save. METAL / PLuG > ae » Ose eee LA INTAKE / . MANIFOLD BREATHER PIPE Simple Vacuum System Saves Fuel and Wear By Joe V. Romig Honorable Mention A VACUUM system, connecting the in- terior of the crankcase with the vacuum influence found in the intake mani- fold between the carburetor and the motor valves, will effect a great saving in oil, gaso- line, and motor repairs. By this system, waste gas that slips down past the pistons is sucked out of the crank- case into the intake manifold and up into the cylinders again for use, instead of being wasted through the breather pipe. Further, as the result of a partial vacuum in the crankcase, which sucks air in, oil is pre- vented from leaking out under the forced pressure in the engine. By using a portion of the incoming air, we get a good hot stream of air that will vaporize the gasoline and give better fuel results. This air also carries oil vapor, which oils the valve stems, and saves much needless wear. The device is very simple. A brass or hard wood plug is made to fit snugly intc the breather pipe, as in the illustration. Into a tapped hole in the top of the plug is screwed a rubber hose. The other end of the hose is bound to the end of a small brass cock, screwed into a tapped hole in the intake manifold. By adjusting the cock, thereby varying the opening, the right amount of air dilution can be secured. Do You Oil All Places that Need It? By L. R. Fritz Honorable Mention I FOLLOW a schedule of regular oiling and inspection. This plan keeps down expenses by saving excessive wear on parts and by discovering the little repair stitch which, taken in time, saves nine dollars. The Ford lubricating chart indicates about 20 things that should be oiled each 200 miles. Actually, more than twice this number need this frequent attention. When touring, I oil these things and turn up the grease cups at the end of the day’s run or before beginning the next day’s run. When at home I oil them a little oftener. Under the hood I oil (7 places): timer pull rod, 2; carburetor pull rod, 2; timer, 1; fan, 1; steering gear grease cup, half turn. Front end (12 places): spindles, 2; con- necting rod, 2; steering gear connecting rod, 2; crank, 1; spring hangers, 4; springs. Under the floor (9 places): hand brake lever, 2; brake pull rods, 2; control shaft bearings, 2; speed lever, 1; 2 grease cups, half turn each. Rear end (13 places): brake rod, 2; sup- ports, 2; spring hangers, 4; hub brake cam shaft, 2; grease cups, half turn each, 2; springs. This is a total of 41 places. Besides the 200 mile oilings there are lubricating items which are needed less frequently and which, with adjustment items, are kept track of by means of a mile- age chart tacked up in the garage. Believe In Your Car By J. Edgar Mitchell Honorable Mention I HAVE my local service station examine my car once every month. I ‘avoid changing drivers and never drive over 30 miles an hour unless absolutely neces- sary. I always specify the name of the oil that is most suitable for my motor, and get the amount that it requires. I never overload my car, and I believe in my car, my service station, and my instruction book. Why Engine Lacks Power Q.—My engine lacke power, although the compression is good and the carburetor is in correct adjustment. I recently had the carbon removed.—R. F. C., New York, N. Y. A.—There are many reasons why our engine may not give full power. If attery ignition is used, see that the battery is not low; if magneto ignition, see that the magnets are not weak. The breaker points should make flat contact and be in proper adjustment. The speek: should be properly timed and the spark-advancing mechanism should be inspected, since lack of power may Write the Automobile Editor About Your Motor Troubles be due to a late spark. Low power may be caused by so simple a defect as a throttle that does not open all the way. Recharging Magnets Q.—Can I recharge magnets on my mag- neto with the alternating current?—A. M. H., Falls, Pa. A. You cannot recharge your mag- nets with alternating current, and you should not attempt the work even with direct current. It is better for you to send the magnets to some —— where they are equipped to do this work. When to Use Oversize Tube Q.—Is it necessary to use a 33 by 4 inch tube with a 32 by 3% inch cord tire?—A. A., Rochester, N. Y. A.—Whether a 33 by 4 inch tube should be used or not depends on the size of the cord tire. Most cord tires are considerably over size, and therefore it is frequently advisable to use an over- size tube, as you suggest. The best way to determine the size of tube required is to measure the tire. If it measures 33 by 4 inches, use a 33 by 4 inch tube. On the other hand, if it measures 32 by 3% inches, use a tube of this size.

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76 Popular Science eee. ee e Monthly ee ey Ee SP PE IOS ale Bani Sy pated id ay LBL Ras. Sietremprs anna —— —_ ee ee Se en tee nop ee et A AE SRR ea ent New Tools and Fittings TADERED PLUNGER OF ae ore Copper tubing for conducting gasoline or oil may be flanged with this tool with- out being removed. One jaw is split for three sizes of tubing TO HEAT Is Yoursa ‘Pleasure Car”? These -——— "a adaptable for general hoisting Se a This new combination heater valve and tuning valve will either lead the hot exhaust gases into the car’s heater or serve as a muffler cut-out when ad- justing the carburetor dimmed on meeting an- other car, the auxiliary lamp shown above illum- inates the side of the road Press the plunger of this dust cap pressure gage and if the cap rises to a No matter how heavy the automobile or motor truck may be, this wrecking car is able to lift and tow it. The car is equipped with a power winch When the headlights are fixed mark, the tire is properly inflated This dust apron, de- signed by a Chicago physician, has a special pocket that covers the steering wheel when the apron is drawn over the tonneau of the car in the garage ci i ~~ —_~— ena oer, A new electrical heating de- vice, designed to keep the engine and the radiator warm during cold weather, consists of a T-shaped cast- ing that is connected with the water pipe between the pump and the radiator. The resistance coil may be sup- plied with current from any light socket The spark gaps, one for each cylin- der, conveniently placed under the hood, produce hot- ter sparks at the spark plug and in- sure proper ignition 7; -CQOTTER-PIN HOOK — & | Leta “iy Y ee ) HAMMER as ¥ $LipE = — a By means of colored lights, this Automobile owners will find much use for the electric dashboard device, shown electric trouble lamp shown above. with cover removed, indicates when electromagnet in its base and will cling to any gas, water, or oil is low iron or steel surface while the current is on When the sliding hammer of this tool is pulled back sharply, the hook at the end of the rod will loosen any obstinate cotter pin ~

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March, 1922

y New and Useful Thin

gs for. the Practical Man to Make |

Electrical Timing Device Prevents Many a Kitchen Mishap HIS device is designed with the idea of keeping the genus homo from seeing red when he sits down to breakfast and finds his eggs under- or overdone. It is also useful for timing other things for intervals of half an hour or less. By setting the contact screw over the numeral 12, the clock will buzz on the hour every hour. In timing any operation, note the posi- tion of the minute hand and turn the glass face of the clock until the contact screw is the required number of minutes in advance of the hand. When the hand makes con- tact with the screw, the buzzer will operate. A frame is made of wood, back and front open, and an ordinary alarm-clock, buzzer, and dry cell are fastened in place as shown on the drawing at the right. Remove the ring on top of the clock and drill a piece of wood to receive the post, as shown. Saw slots in the bottom piece and fit in blocks, front and back, to hold the bot- tom of the clock in place. A sectional detail is shown of the glass face of the clock, in which a hole is drilled. A screw made from a standard binding- The buzzer gives the alarm

post is fastened in place with some kind of a spongy washer between the wire and the glass in order to take care of expansion. The wire from this contact screw is connected with one binding-post of the buzzer. The other buzzer connection is made to one post of the dry cell. It is well to make one end of this wire a slip-on connection in

LEAD TO order that the BUZZER GLASS buzzer may be Contact detail disconnected when desired. The wire from the other binding- post of the dry cell is soldered to one foot of the clock. This device will soon be declared by the 200k to be the handiest thing about the

By, Oliver L. Stevens (First Prize in ‘‘New Uses for Electricity’? Contest)

f= SS SSS] ' : SSS S— | = PS }| : | : )} | |suzzemmye aie, ~ \ | . fr Sou! Ba = \ \ ae (SS a i | emer i ISR 2. I <4 ? a] jot = Wal = Fie aia Wha = ie 7 { I

Mr. Stevens’ own drawing of the simple timing device kitchen, but it has still further applications. The next step is to connect it with the gas- range so that it will turn off the gas. This is done by providing a somewhat larger box than is necessary for the buzzer timing device alone and constructing a slide at one end so that a weight—in this case a piece of a bar of anti-friction metal that happened to be in the junk box—can slide freely up and down. A catch is made by bending a piece of 14-in. round iron bar —any strap iron can be used—into a hook shape. One end is flattened and drilled so that it can swing from a block at the top of the box alongside the slide in such a way

Live Electrical Ideas HE four best contributions to the contest on “New Uses for Electricity,’ appear in this month’s Home Workshop. The prizes awarded are: First prize of $50 to Oliver L. Stevens, 116 Kirk Ave., S. W., Roanoke, Va. Second prize of $25 to R. A. Squires, 517 W. Main St., Louisvil e, Ky. Third prize of $15 to J. W. Fr tsch, 1525 Chew St., Allen- town, Pa. Honorable mention, R. E. Nelson, 2910 Exeter St., Duluth, Minn.

‘throughout its length. that the hooked end passes through a hole in one slide and projects just far enough to prevent the weight from dropping. Bell magnets are mounted on another block so that when they are energized they will attract the latch and thus permit the weight to fall. The magnets are connected in the same way as the buzzer and a two-way switch permits either the buzzer or the magnets to be used, as desired. A piece of picture wire runs from the weight up through a hole in the top of the box to a handle on the gas-range in such a way that when the weight drops, the handle is turned to the off position. In this case it very conveniently ran up over the feed pipe, where it passed through a wire “eye’’ or guide fastened to the pipe with friction tape, and was attached to the cock around the head of the machine screw that holds the porcelain handle in place. It was ar- ranged to turn off only this one burner, although it could have been used for the other burners as well. It is obvious that with a little ingenuity in attaching it, the device could be made to do many similar things. It could be-ar-

The timer arranged to turn off a gas-burner ranged either to turn off or on an electric stove or store-window lights or anything of that kind by simply placing the box under a knife switch and hooking the wire to the switch handle. The timing device might also be used to serve as a substitute for an elaborate and expensive “‘program’”’ clock, especially if the intervals to be rung were an hour apart. If it were desired to have two bells ring, perhaps one on the hour and another five minutes afterward, as in a school, two contacts could be arranged 30 degrees apart. To ring the bell or buzzer for a longer interval, the contact should be a beveled strip thick enough so that the minute hand will make a firm sliding contact with it The circuit will then remain closed as long as the hand is passing over the strip.

| )

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alti Popula Science Monthly Outfit Receives Continuous Wave Radio Signals Being the Third Article on Wire ess Receiving Sets by Arnold Holmes detectors and amplifiers, such as were described in detail in the December and February numbers of POPULAR SCIENCE MONTLHY, are capable of receiving only spark signals or modulated continuous wave signals. That involves detection alone. Figure 1 illustrates the sort of volt- age across the detector resulting from de- tection, which is, in effect, rectification. The current in the output of the detector is asshown. The current through the tele- phones is the audio frequency current; that is, the frequency at which the ampli- tude of the radio frequency current and voltage vary. That variance is what makes spark signals and modulated signals audible by detection. The question then arises, how are con- tinuous wave signals made audible? Upon detection of continuous-wave telegraph signals direct current results. That, of course, is not audible in the telephone re- ceivers except in the form of a click. In order to make continuous-wave signals audible, another frequency generated by the receiver, which differs from the re- ceived signal by an audible frequency of perhaps one thousand cycles, is impressed on the detector together with the signal. These two frequencies produce beats occur- ring at a frequency that is the difference between the signal and local frequency. Upon the detection of this high-frequency voltage, whose amplitude varies at an audible rate, the low frequency is obtained that becomes audible in the telephone re- ceiver. What apparatus is needed to accomplish this? Figure 2 is a circuit diagram of a receiver that is arranged to receive con tinuous-wave signals. The local oscilla- tions are produced in the circuit Lz Ce by the vacuum-tube oscillator, which is of the feed-back type. Oscillations are produced in the circuit by feeding some of the ampli- fied high frequency in the plate circuit of the tube back into the input. This is con- trolled by the coupling of the tickler coil (L3) with the secondary coil (Lg). é )« PLE wireless receivers and audion

| | { antenna ie CONDENSER ~<}— PRIMARY

Fags 4 FREQ. CURRENT VOLTAGE RECEIVED FROM SPARK STATION IMPRESSED AT A-A ' | 1 peo sos das k VOLTAGE AFTER DE= Wu. TECTION ACROSS B-B Mu | Ma | Winn

CURRENT THROUGH TELEPHONES C-C. SP ae it THE RADIO FREQUEN= CY COMPONENTS ARE By-PASSED BY CON= DENSER D-D.

DOT DAS! DOT \ AN CW. VOLTAGE RECEIVED FROM C.W. TELEGRAPH STATIONS COMPARED WITH SIGNALS FROM F TATI DoT DASH SPARK STATION | AN bh bl ttc CURRENT THROUGH imei mene BR TELEPHONES NO SOUND, EXCEPT AT BEGINNING AND END OF SIGNAL SHORT & LONG TONES AAA NWA A\ASPARK DUE TO SPARK- FREQUENCY CURRENT

ANTENNA Fig. 1. Diagram illustrating the transformation of sig- nals at various stages between antenna and telephones SHUNT CONDENSER A B Cc YD TELEPHONES aa — DETECTOR D A B Cc GROUND

AN \__\ Ti RADIO FREQUENCY

VOLTAGE RECEIVED FROM CONTINUOUS he WAVE STATION MOD= ULATED WITH TONE OR SPEECH VOLTAGE AFTER DE= tua TECTION ACROSS B-B ANA ; MAMAN CURRENT THROUGH TELEPHONES C-C.

ANAAAKAANAAAAAAAAAAAAAAAN! SIGNAL FREQUENCY WANA LOCAL FRequency wt WirannVViraeot Winans WWVirneaWiy VOLTAGE ACROSS B-B CURRENT COMPONENTS ARE BY-PASSED BY CONDENSER D-D. 400,000 CYCLES 401,000 CYCLES \ | SUM APPLIED TO v DETECTOR A-A ENVELOPE 1000 CYCLES 4000 CYCLE TONE CURRENT IN TELE=

PHONE RECEIVERS C-C

A very convenient receiver for this range of wave lengths is illustrated in Figure 3 on the following page. The uni- versal mounting shown allows the coupling to be varied between antenna and second- ary circuit and between tickler coil, not only by moving the coils apart, but by actually rotating them 90 degrees with re- spect to each other. This provides a fine degree of variation of the coupling. By the Primary Inductance For Antenna 400 M-mfds 1500 to: ‘2700 meters, coil No. 100 Coil No. 2000to 3600 ‘* ** No. 200 - ** No. 3100to 5500 ‘* * No. 300 oe ND: 5300 to 9300 ‘ ** No. 500 ae 7900 to 14,000 “ “ No. 750 ‘“* No 14,000 to 24,000 ‘ ** No. 1250 Pr em Tickler Coil use of honeycomb or duo-lateral coils the wave length range of the set can be made almost anything. The size of the coils that should be used may be determined from the accompany- ing list of the duo-lateral coils required to give a wave-length range of from 2000 to 15,000 meters, using a tuning condenser of from 50 to 1000 micro-microfarads (.00005 to .0010 microfarads). Secondary Inductance aoe 1800 to 6000 meters coil No. 400 750 3500 to 11,500 ‘ * No. 750 ; 1250 7500 to 24,000 ‘“ ** No. 1500

id | SECON DARY CONDENSER Co

Fig. 2. Wiring diagram

for simple continuous

wave receiver elude LTS

FILAMENT BATTERY | 6 VOLT:

1 PLATE BATTERY 44 VOLTS

na

A long-wave receiving set

Mc

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Re De ee

Page 63

| March, 1922 "Ww Yo" < 4% er SPRING WASHER were secured at CWWIRSAS INAS i = QS PANEL an electrical \o43'ROUND-HEAD MACHINE 5¢ 364 POINTER. HA shen, tae See ee INE SCREWS INTER. Ye" STOCK IN KN lis ‘8/52 FLAT-HEAD MACHINE SCREWS DETAIL*#1 SCREWS LOCICWASHER SS “Fen ra ee

RUBBER KNOB old reed organ, Details of coil winding and coupling arrangement

This receiver can be used with the de- tector amplifier described for the simple re- ceiver by connecting the tickler coil to the proper binding-posts. In connecting the tickler coil, it should be remembered that it must be correctly poled. The photograph shows a convenient and neat detector am- plifier and cabinet. With this receiver the high-power transatlantic and transpacific stations, the naval stations, and most of the post-office stations engaged in sending out market reports can be copied.

Using Electricity to Put the Baby to Sleep By R. A. Squires (Second Prize in “New Uses for Electricity’? Contest) HEN our baby arrived, he started life with a severe case of colic, which kept us up at all hours endeavoring to quiet him. We shortly discovered that gently shaking him up and down in his crib would induce him to be perfectly quiet— as long as we kept it up. This became mighty tiresome, even when my wife and I took turns, and after a few nights we were both worn out. So I proceeded to contrive a mechanical means toshake the baby by mounting a discarded fan motor on a base se- cured in the lower part of thecrib. I ran a belt from the small] pulley on the motor to a 6-in. pulley mounted on a short piece ofshaft, which was provided with two bearings and a base for attaching. On the other end of shaft I mounted a collar and drilled it for a crankpin about 3¢ in. off center. I then made a short con- necting rod, one end with a bearing to snugly fit the crankpin, the other end attached to the center of the springs in the crib. The connecting-rod was later pro-

The crib springs are gently joggled vided with an adjustment to compensate for the baby’s weight as he grew older. This device moves springs, mattress, baby, and all up and down about 34 in.ina smoothandreg- ular manner. A means of regu- lating the speed was provided by the use of a small self-con- tained rheostat sold for dim- The motor as usually oper- ated consumes about 20 watts an hour. Does it work? Well, the baby is now over a year old. He has never miss- ed a day going to sleep with the aid of the shaker, and we have never had to stay up at_night to rock him or shake his crib since we put the electric shaker to work. The outfit is self-contained with the crib and can be placed in any room. It has a cord connection for attaching to any con- venient socket. I might add that the crib is also equipped with electric milk-warmer and night-lamp.

Automatic Electric Doorbell Chimes By J. W. Fritsch (Third Prize in ‘‘New Uses for Electricity’’ Contest) HIS device, requiring merely a mo- mentary push of the front-door push- button, was designed to play the “Long Meter Doxology.” The playing of more difficult selections is possible by the careful placing of the contact points. Three cells operate a toy motor, which drives the grooved wheel H. To H is attached a wooden commutator J, surfaced with sheet copper, in which there is a break of about 14 in. to act as a circuit-breaker

March. 1922 by disengaging one of the brushes at the completion of one revolution of H. One binding-post of the motor is connected with the pushbutton and with one of the brushes mounted in the upright U. The other brush is connected with the battery and from this same cell-pole another wire runs to the pushbutton. The other end of the battery, which is in series, is connected with the other binding-post of the motor. Upon a touch of the button, the motor ming a lamp. - The chimes

producing the octave from G to G', were mounted thereon. One wire connects all bells with another three-cell battery. From each bell a separate wire leads to one or several cam-headed bolts inserted through J, which is made of wood. The music be- gins on note C, therefore the C-bell wire connects screws 1, 2, 6, 13, etc., or all the C notes. The heads of the bolts are beveled on one side, making one edge quite sharp and flush ,

with the surface of The J, in order mechanism to lessen the fric- tion, to in-. sure ,good PUSHBUTTON

& BELL WIRES TOC

UPRIGHT

ge SHELF Sa SAMPLE 2 BRUSH 6 BELL WIRE TO BELL C ‘ipa WIRES brush contact, and to make certain the sharp breaking of;the circuit after each note. The brush K, made of copper, is attached to H by a bolt from which runs a wire to the metal collar on the axle con- necting with the other pole of the battery through the cast-iron upright L. Since the stanza has four lines, a suitable pause is produced at the end of each by spacing each set of eight bolts somewhat apart. One end of the axle is carried by M, which is made of wood and is somewhat thinner than J.

Page 64

80 Simplifying a Difficult Milling Machine Job N milling out an irregular depression in a piece of metal, much time is lost in lowering the table to measure the depth of the cut and then resetting the work to the tool. A template is required to gage the curvature of the inside surface, and when a template is made, it is quite as simple to make it correspond with the cut to be made. The job is then an easy one, as a small wheel is set on the mandrel outside of the | (GUIDE; WHEEL ¢ : —£— MILLING- pemess CUTTER Ko J IN SECTION Template prevents cutting too deep work and the template clamped against the work. The operator of the machine follows the profile, making it impossible to cut inaccurately, provided the template is clamped correctly.—L. A. G. Machinist’s Try-Gage for Cylindrical Surfaces HIS try-gage has proved very useful in setting up cylindrical work on drill- press, planer, shaper, and slotter, and is ena This machinist’s tool is a time-saver a used by two men in the shop with which I am connected. The tool should be made of steel carefully finished all over, with a level about 11% in. long attached to the top.—WALTER WELLS. Non-Clogging Hollow Punch | hamerrsthed punches, such as are used for cutting belt-lace holes, rivet holes in fabric, or center holes in washers of rubber or leather, are dif- ficult to make be- cause the center hole must curve outward to the side of the punch to permit the pas- sage of the cut out disks. There is, however, a simple = way to make this puycu compLere type of punch. ec ” Take a length of waitin anal hexagonal or circular bar stock, heat and bend it, and then drill it as shown. Next straighten the bar, grind the end, and temper it. This method will provide a curved orifice that will not clog.—A. L. ceases PIECE OF DAR STOCK SAME BENT &’ DRILLED THEN STRAIGHTENED OUT GROUND AND TEMPERED 82 "Tools, like fine weapons, are very won- derful things when you come to know — | them well. They have made history. Every time we pick up a saw or an auto- matic drill or our “‘mikes,’”’ we are taking advantage of tool-building discoveries and achievements that run all the way back to the Age of Bronze. There is no excuse for the man in the home workshop not having his tools always in good condition. And yet how many times have you seen a handy man labori- ously hacking a shelf or what not out of a board with a dull and rusty saw! No won- der he has not the satisfaction in his work always felt by those who have the true craftsman’s attitude toward tools—pride in their good condition. Look for a moment at the sketch at the head of this article—a plane redrawn from Ernest A. Batchelder’s book, “Design in Theory and Practice.’”’ It was made in medieval times, when many of the tools we use so casually to-day would have been regarded as little short of miraculous, but it leaves no doubt as to the craftsmanship of the man who made and used it. Would you have any hesitation in saying that he knew how to use tools and how to care for them? The few pointers I should like to suggest to the home worker—whether he inclines toward woodwork or metalwork, whether he has an elaborate shop or wishes to do merely a few odd useful jobs around the house—are these: Buy only the best tools—expensive at first, but an economy in the end. Be sure to get the tools you really need. Only the expert mechanic can do good work with makeshifts and he usually won’t try, for often the time and material wasted on a ARTHUR Popular Science Monthly alks WAKELING single job is worth more than the cost of the proper tool. If, however, you have only a limited amount to spend on tools, choose a few good tools rather than a number of cheaper ones. Learn to use your tools with the utmost precision and skill so that your work will always be finely done. The best way is always the easiest, the simplest, and the quickest in the long run. To maintain edge tools in proper condi- tion, notice the cutting angles that have been given to them by the manufacturers and preserve the same angles through the life of the tool as nearly as possible. Tool angles may range all the way from those of a penknife to a heavy lathe tool. It is always a matter of selecting an edge that will be sharp and reduce friction and at the same time strong and permanent enough to stand up under the work to be done. You may be sure the toolmaker has worked the angles out very carefully, so that all you have to do is to use your grindstone and oilstone constantly to keep those angles right. Having edge tools well sharpened and well lubricated is half the battle. Tools of the hammer, punch, trowel, and wrench class will not trouble you much, but the tools you use for making and test- ing measurements deserve your greatest consideration. Even a steel square or try- square can quickly be spoiled by a little carelessness; and rules, gages, calipers, surface plates, protractors, levels, and the like, require the best of treatment if they are to retain their accuracy. Protect these tools in every way from being strained, warped, nicked, or damaged. These hints, if adhered to, will, I am con- fident, help make your home workshop at once more pleasurable and more profitable. A Bookcase that Folds into Small Space By Robert H. Raymond OR students who live in crowded quarters or who travel much, this book- case will prove of value, for it can readily be put up and taken down and occupies little space in a trunk or box. Make three shelves % in. by 8 in. by 2 ft. 4 in. of any common wood. Bore a Yj-in. hole at each corner 1 in. from the edges. All the shelves may be held together with a hand screw and bored at the same time. The appearance of the shelves depends on hard-wood strips of mahogany, oak, walnut, or other cabinet woods mitered around the front edge and the ends. They should be the same width as the thickness of the shelves and 4% in. or % in. thick. Fasten them with brads. Then stain the shelves oak, mahogany, or whatever stain will harmonize with the wood you selected for the edges. Four pieces of 3/16-in. manila rope or strong cord, colored if preferred, about 114 yd. long, are knotted and passed through the shelves, leaving about 10 in. and 9 in. respectively for the lower and upper book compartments. The knots must be spaced Three boards form this bookcase BOARDS— 28"*8"« H : G == bh, SS LL i Zi SUGGESTIONS FOR EDGE MOLDINGS exactly alike on each piece to insure a workmanlike job. At any time an addi- tional straight length may be carried up to the ceiling, or to the picture molding if it is well nailed. XM -_* SL a ll

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nthly > ost of mited r good ones, tmost k will ray is d the -ondi- have turers h the Tool ose of It is » that at the 10ugh done. orked ll you 2 and ingles pened |, and nuch, _test- atest r try- little ipers, d the they these ined, | con- op at able.

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March, 1922 81 25 Cal. Automatic No. 152 is 25 Cal. automatic as illus- trated. 7 shot. Has double safety and is practically fool-proof against accidents. Handsome blue steel gun metal finish. Checkered grips. Ac- curate aim. Rifled barrel. Lies flat and will not bulge out pocket. Big Bargain $ Our special price 9.75

Protect your home and earnings It is of vital importance “ that when you need a firearm it cen must be absolutely dependable. Everyone of our automatics is made of finest materials by ex- pert workmen, and then fully tested before leaving factory. That is why we can sell them with an absolute guarantee of money back if not satisfied after examination. We are undoubtedly the largest direct-by-mail distributors of revolvers—selling thousands direct-to-the- consumer. That is why we can offer you a genuine bargain dependable automatic for the heretofore unheard of_rock bottom price of $9.75. Every one owes it to their family and to themselves to keep one of these new safety 4 = automatics always at_ hand, Frightened A to fully protect against burglars, thieves Noise Downstairs and hold-up men. ee en ——— $] 750 No. 3652. Same style as above only 32 cal., 7 shots. Big Value. $1 1 Our price only............ No. 552 32 Cal. Military $12 aZIS LOVX4

Model.. 10 Shot, extra magazine free making 19 shots.

It is a terrible fright to wake up in the night—hear noises down- stairs and realize that your neglect amous Py has left you wholly unprotected. One of these famous Paramount Revolvers will fully protect you. Texas Ranger Hand Ej ector Popular Swing-Out 5 0 cylinder revolver made by expert . \ : nee mechanics and extra fine steel. >...4 Model adopted by police and secret

service in many cities. Nickel or blue finish. ot : Pearl handles $3.00 extra. When ordering state, | : whether nickel or blue finish is desired. Naw 1073) S2 Caliicinc sence $17.50 and postage H d Ejector No. 1573, 38 Cal Be crncstevales ts $19.00 and postage | Double Action Automatic The fact that this gun shoots 7 times without reloading makes it very desirable. This is the only ; hand ejector side swing that has a safety feature which will prevent accidental discharge. Has swivelled handle and is made for rough use. Of excellent material. The barrel is 4 inches long, rifled and shoots the famous 32-20 cal. cartridges which gives it great penetrating power. We are selling this gun at a remarkably low price and the Paramount Trading Co. guarantees that you will be entirely satisfied with this wonderful bargain. VP. ONADA NESS ins Grain eae $14.50 and postage. Ejector $ w= This handsome firearm is ac- curate and dependable. Only dependable weapon at a low price made. Has popular break cylinder made of extra fine nickel steel. Shoots 5 _ times before re-loading.

No. 2022 is 32 Cal. 3% inch barrel. Pay postman $7.75 and postage on arrival. No. 2522 is 38 Cal.314 inch barrel. Pay postman $9.00 and postage on arrival.

Genuine German LUGER Automatic No. 3010 is 44 Cal. 6 shots. Nickel only. g No. 4152. 30 Cal. We guaran- for this gun $14.50 and postage. tee this to be the latest design $5.00 per 100 Cartridges for the break and swing can be bought anywhere, or can be furnished of the famous Luger automatic, by express for any of the above by express only. For 32 Cal., $3.50 per 100; for 38 Cal., also that it is a genuine Luger and not a Luger only | $4.50 per 100. Model. It shoots 9 shots. Has automatic maga- zine ejector, safety devices, which makes accidental discharge impossible. Shoots 30 cal. ammunition, which we will furnish or you can secure from your local dealer. Exceptional value. $2 8.50 Or BROCE POS: ii-<oeccnicewovisc canine Cartridges

MONEY-BACK GUARANTEE The Paramount Trading Co. guarantees that these are all brand new guns and not reclaimed. We further guarantee that you will be entirely satisfied with your purchase and if for any All 25 and 32 Cal. Automatics shoot all reason you are not satisfied return it to us immediately and we por my merry ey ge ol will refund your money. We also guarantee that your revolver 25 Cal. $3.75 per 100; 32 Cal. $4.50 per 100. will be delivered in perfect condition to your door. You take absolutely no risk in ordering any of these guns as our guarantee SEND NO MON EY protects you in every way. Rush your order to-day. Be sure to mention the number of the gun you wish. Select the particular revolver that suits your particular needs to-day. Write clearly your name, address and number of the ' HOLSTERS revolver you desire (a post card will do). Handsome genuine leather holsters. These holsters The postman will deliver your revolver to your door, for we ship and are of the best material. durable and. we guaranvee by return mail. Pay postman on arrival, our price plus the few them 9 pred wear. cents postage. Send for FREE Catalog. pop ay on ve le a a a $1.00 PARAMOUNT company New York, N.Y.

Page 66

Sp yacialbical +) saahnemnetnas ac ap liter ae SERNA Dae, G er ae? ee ee ante aia ow feces cate nec reat haghrgnre es Ae i ane 82 Popular Science Monthly Our Blueprint Will Help You Make This Smoking Cabinet SMOKING cabinet with self- contained ashtray in each end To order a blueprint, fill out and mail the coupon at the bottom of this page. forms the subject of the second blue- print in the series prepared by the Home Workshop Service Department. Every man who works with tools, whether he is a novice or a mechanic of long experience, will find this prob- lem interesting, not alone because of the unusual attractiveness of the de- sign, but also because he can make the cabinet in a number of different ways, ranging from easy to difficult. The humidor part of the cabinet is a box 8 by 10 by 16 in., with joints that are very nearly airtight. When the lid is lifted, two pins may be pulled up to release small doors, one in each end. These doors dropping to form an angle of about 45 degrees with the ends, support two hopper- shaped removable ashtrays. The trays and other metal fittings can be constructed easily by the home worker from sheet copper or brass. The whole arrangement, besides being novel in design and a neat piece of eraftwork, has the advantage that when the ashtrays are not in use, they are closed up within the box. ye The interior of the box, intended for cigars and cigarettes, can be cigarette holders, and pipe-cleaners. Four methods of finishing the stand are suggested. It can be enameled black and painted with a colorful de- sign, somewhat reminiscent of peds- ',| ant art. This is both effective and easy, because any imperfections in ||| the workmanship can be concealed and the joints could even be fastened | with brads. The second method calls || for a natural finish, in which case only || fine woods should be used, preferably mahogany, walnut, or quartered oak, The third method involves simple wood-carving, done with a carving tool or small gouge. Although this is a most artistic and craftsmanlike way of ornamenting the box, it re- quires no special skill in wood-cary- ing, since the lines are all straight gouge marks laid out in an interesting divided into compartments if desired. The design provides for two small troughs for match-boxes, cigar and The cabinet may be made plain, carved, inlaid, or enameled black and decorated with oil colors pattern. The fourth method sug- | gested is to inlay the box with band- ings, which is intended only for ex- perienced workers. If it is not desired to make the stand, the box alone will be a project well worthy of your best efforts. A blueprint, 15 by 22 in., contain- ing complete working drawings and bill of materials, will be sent to any ij reader of the Home Workshop for twenty-five cents. If you wish one, please fill out the coupon at the bot- tom of this page. Coldframe and Sash Simplified for the Home Worker A cheap and easily made coldframe BY the following simple method a strong coldframe sash may be made cheaply in the home workshop. The same tools will be needed as for the storm sash described last month on page 120. , Any size desired may be made; the ex- ample given is 2 ft. 8 in. by 4 ft. 6 in. for the sash and 2 ft. 6 in. by 4 ft. 4 in. for the outside measurements of the frame. The stiles (side pieces) ° day, and it is 5 in. wide. Cut it off square at both ends, 2 ft. 314 in. long. The top rail will be 14 in. longer, or 2 ft. 4 in. in length. Cut it at each end as shown in Fig. 2. The stiles are 4 ft. 6 in. The 3 bars are 1% by 1 in. rabbeted on both edges, as shown in Fig. 5. They should be 4 ft. 4 in. long. The cut for the bars at the top is similar to that in Fig. 2 and they should be securely nailed with 114-in. brads. At the bottom the cut is as shown in Fig. 4, small mortises being made in the -bottom rail. The bars are fastened to the face of the bottom rail with small screws, as shown in Fig. 4. The sash may be nailed together with tenpenny nails set well in, and then bored for dowels, as shown in Fig. 2, or fastened with twentypenny nails, for which holes should be bored a trifle smaller than the diameter of the nails, as shown in Fig. 3. Instead of glue, white lead should be ap- plied to all joints before nailing. Precau- tion should be taken to see that the sash is braced square before putting in the dowels of the twentypenny nails. T-hinges may be used, if desired, as shown in Fig. 7, and, to give additional strength to the sash, 6 in. flat corner plates may be FIG2 FIG | COMPLETE SASH 4 Yj Lf, Vis , ASTILE / FIG.3 % WILD: VEZ A Va SIL AstTILE -.20-D. NAIL “BOTTOM RAIL FIG.4 + Ys ne OC MA HTT, | Wj ____ 2 ZT TSASH BAR “MORTISEFOR BAR «= BOTTOM RAIL T-HINGE FIG? LONGITUDINAL SECTION FIGG CUT FOR SIDES i T} A n Re L if Complete details of sash and frame placed on each corner on the lower side. The coldframe, as designed, is of 10-in. plank. If this is 2 in. thick, the required material is 3 pieces 4 ft. 4 in. long and 3 pieces 2 ft. 2in. long. If it is 114 in. thick, the last 3 pieces should be 2 ft. 3 in. long. Cut one of the short lengths in two pieces, giving a slight bevel to the saw and mak- ing one piece 2 in. wide, and> the other 8 in. wide. Cut one and top rail, like those in the storm sash, are 11% in. by 21% in. rabbeted on one edge only, 14 by 5/16 in., as seen in Fig.2. The bottom rail is %- in. stuff, which is actually 11/6 in. Name less as ordinarily mahufactured to- I. GENTLEMEN: Please Use This Coupon for Ordering Blueprints from the Home Workshop Service Department The Home Workshop Service Department, Popular Science Monthly, 225 West 39th St., New York. Send me the blueprint or blueprints I have checked below. I enclose 25 cents for each one. No. 1 Sewing- or Work-Table . Sates 6 0b eS 0 0 0 Oe 6 0.66 0 bes 25.0 0.66.0 6.60.58 66 es No. 2 of the long pieces as shown in Fig. 6. The frame is now ready to be spiked together with heavy pieces nailed down the in- side corners that will serve to ren- der it more dura- ble and workman- like.—A. E. Smoking Cabinet e 5 a. Ma tT Pe es 7s oy Tt 3° and mos ofa Bea nat as tot the

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thly ners, tand eled | de- eds- and S in aled ned -alls nly bly ak, iple ‘ing s is like T'v- ght ing ug- nd- eX- she ect nd ny for e, »t- ey A et — Ww wre |

March, 1922 - . »G “ _ (aN —-= oa ® ~ ‘D a) iA ‘ “ ———S== sg ———

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The Radio Magnavox, Type R-3, with 14” horn. Beautiful and durable as it is efficient. Reproduces wireless music and messages in volume without dis- the Radio Magnavox. S ® plated trimmings, and solid mahogany tortion. Anyone can operate it, base with piano finish. Indispensable every one can enjoy it. No ad- to those who take pride in their set and justments or extras required. the results achieved. No radio set complete without one. There is no substitute for or home entertainmentsv NTERTAIN your friends with radio con- certs, enjoy the fascination of radio as a hobby, make wireless a profitable part of your business, get news and market reports before they are published, take public speeches off the air. With a simple receiving set and a Radio MAGNAVOX you can do all this, and more, too, in your own home or office. The front cover of this magazine shows how easy it is, with a Radio MAGNAVOX. Practically every variety of vocal and instrumental music from jazz to grand opera, news reports in plain English, and many other special features are radio broadcasted daily, free to anyone with the sim- ple equipment to receive and reproduce them. Read the article in this issue. The Radio MAGNAVOX will reproduce them for many people at the same time. Without the MAGNAVOX only the operator wearing a head set can hear. Simply substitute the MAGNAVOX for the head set, hook up with a Magnavox Power Amplifier, and an audience of one or one thousand may

Magnavox an name of neares' same. NAME

Magnavox 3-Stage Power Am- plifer. Same as 2-Stage, type, ex- wore, RADIO HAGNAVOX THE MAGNAVOX CO.—General Office—OAKLAND—CALIF. NEW YORK OFFICE—370—7th Ave.—Penn. Terminal Bldg. Please mail this coupon to Magnavox office nearest you. Please mail me, without cost or obligation, your very interesting folder illustrating and describing the Radio d the Magnavox Power Amplifier, also hear perfectly. This MAGNAVOX equipment enables every- thing received by radio to be swelled in volume to the full sound intensity required for any occasion, without losing even the most delicate tone modulations or a single bit of the original clearness and distinctness. It makes a radio set adaptable for office, store or factory use, and the use of radio music practical for home entertainment, concerts and dances. It adds to any set the final touch of up-to-the-minute completeness and mul- tiplies its scope and usefulness many times over. You yourself can operate the MAGNAVOX the very first day without any previous training or experience. The hook-up is easy, and there are no adjustments. The few instructions neces- sary furnished free with each outfit. The entire cost no more than the price of a good phonograph. Any first class radio dealer will install it for you, and give you any further assistance required. The Magnavox Company are world pioneers in the develop- ment of sound amplifying apparatus. It was MAGNAVOX apparatus used by the U. S. Navy and the U. S. Signal Corps to perfect their communication during the Great War. It is MAGNAVOX apparatus now being used by the majority of prominent speakers for addressing large audiences. The facilities and experience which developed this apparatus are back of each piece of equipment bearing the MAGNAVOX trade mark, and are available to you now in making radio simpler, more useful and more enjoyable. Write us a letter or mail the coupon below to our nearest office for FREE Magnavox folder.

t radio dealer who can supply me with

cept larger and more powerful. Designed to energize MAGNA-

ADDRESS

Facer Designed to furnish po

This trade mark on all MAGNAVOX apparatus,

X where particularly large volume is required for hospitals.

Look for it, Accept no public buildings, outdoor enter- - substitate. If you wish list of tainment, etc. The final touch of completeness to any set. Solid mahogany finish. and information concerning same, place a check mark here [j

other Magnavox Sound Amplifying devices,

Solid mahogany case.

Magnavox 2-Stage Power Am- or the Radio MAGNAVOX, and minimize the possibility of sound distortion where maximum re- sults are necessary. All binding posts plainly lettered. Simply throw the switches to operrte.

Page 68

tes ey aia i ag oreo aR et el ie HPL CAN AARP TIRE 2 5 iA Kai OLA ERG AS RF GOT eee Shi mn ee SAAT emeeyst ‘ “7. Eaton Co,, Starts Your Car Instantly in Coldest Weather When You Step on Your Starter — made for all cars and trucks VERYONE knows how difficult it is to start the motor in cold weather. That is because gasoline vaporizes very slowly when cold. Long continued use of the starter to overcome this condition leads to damaged battery, undue wear and tear on starter, a waste of gasoline and crank case oil dilution. The Aske Electric Vaporizer, by breaking the gasoline globules into finer particles and electrically heating before entering cylinders of motor changes a cold, wet, sluggish mixture into ‘a dry, active gas that gives instant starting of motor. Any motor will start instantly in the coldest weather, when equipped with our vaporizer. Reference to illustrations shows the simplicity of the Aske Electric Vaporizer, and easy manner of installing. It fits like a gasket be- tween carburetor and intake manifold. Push- ing switch button on dash for a few seconds heats the copper grids with current from lighting battery. When motor is started, gasoline is drawn through these four grids and atomized and preheated in passing. As soon as motor starts, taking finger from switch automatically shuts off current. The Aske Electric Vaporizer, in addition to being an almost indispensable convenience, saves battery, starter and time; while the reatomizing of gasoline also produces a gas saving of 20% to 25%. If your dealer is unable to supply you, write to nearest distributor, or the manu- facturer, at once. You need the Aske this winter. Money-back guarantee. Dealers: The Aske Electric Vaporizer meets a real demand that has been await- ing this solution of cold weather starting difficulties. Write to nearest distributor to- day for literature and particulars of our liberal proposition: Now is the big season —don’t delay. ; 50 complete with automatic Price $7.50 switch and everything necessary to install. Easily and quickly in- stalled in an hour or less without alteration to motor. Manufactured by KASE ELECTRIC COMPANY 10-15 Sherwood Bldg. Duluth, Minn. DISTRIBUTORS: Horgan-MacDonell Co., 939 Washington Blvd., Chicago, Ill. Tri State Sales Co., Palladio Bidg., Dept. 1, Duluth, Minn. Kase Electric Co. of New York 136 Liberty St., New York City Winnipeg, Canada. Popular Science Monthly THE HOME WORKSHOP . “7 HAT is your “best idea” for the Home Workshop? A first prize of $15 and a second prize of $10 will be awarded in April, May, and June for the most interesting, useful, and attractive articles contributed to the Home Workshop. These monthly prizes will be a bonus given for especially good suggestions of the kind used in this department. In other words, each idea that is available for publication in the Home Workshop __will be purchased at the usual rates, and the prizes will be in the form of extra checks sent out when each month’s competition is decided. It is, of course, preferable that the | articles be as short as possible, con- sistent with all necessary accuracy and | clearness, and illustrated with sketches or photographs. The sketches need You Have a —_ to Win a Liberal Bonus by Sending Your “Best Ideas” to the Home Workshop not be finished drawings, but they should convey adequately the writer's idea. There is probably not a single reader of POPULAR SCIENCE MONTHLY who has not in his experience run across just the sort of idea that might win a prize. Send your contributions in as promptly as possible, addressing them to the Home Workshop Editor, Popular Science Monthly, 225 West 39th St., New York. The March prize-winners in the old “Best Idea’’ Contest, which is con- cluded this month, are as follows: FIRST PRIZE, $35: R. A. Houston, S. Charleston, Ohio (see page 89). SECOND PRIZE, $15: W. D. Ken- drick, Miami, Ariz. (see page 85). | | -yow often have we looked through a stack of paper-cased phonograph records and left them “kicking’”’ about the room for some one else to put away? This wouldn’t happen if the records were kept in a rack like the one illustrated, where they are instantly available and can be turned like the leaves of an open book. It takes no more time to replace them than to lay them on the table, and any and every make or size of flat record can be accommodated. The rack will be such an attractive adci- tion to any table that it is advisable to make it of quartered oak or mahogany, if there are not some pieces of broken furni- ture around the house that can be utilized. Besides screws or brads, you will require a 6-in. coil-spring 14 in. in diameter, and two sixpenny nails. The end pieces are % by 8 by 9 in. and may be shaped and ornamented in any way desired. Simple line carving will be effective and appropriate, or the design can be stained or inlaid with bandings or marquetry, or the ends can be left plain— whatever the surroundings demand. The other material required will be two pieces % by 4% by 8 in., four pieces % by 2 by 6 in., two pieces 4 by 3 by 8 in., and one piece of soft wood % by 4 by 12 in. On the center line of the latter, 4 in. from each end, bore 34-in. holes and cut out a %-in. slot between them. Then assemble the ends and slide them on to the long piece. Connect the coil-spring by placing it in the slot and attaching each end to a nail in- serted through holes drilled as indicated. Design for Phonograph Record Rack | By Roland B. Cutler The ends will then be drawn together by the action of the spring. To the bottom of each paper envelope attach two cardboard tabs. These should extend about 114 in. below the bottom edge and be a trifle more than 4 in. apart. They can be attached most conveniently with sealing-tape, 7 in. of which will be sufficient to go around the piece of cardboard and stick to each side of the envelope, as shown. This will take but a moment for each record. To adjust the tension of the spring for the number of records it is desired to | keep in the rack, shift the nails from one hole to another in the upper cross block. The space at the ends can be used for record catalogs, if desired. ee

Page 69

cy rs er 10

the ope uld dge hey yith ent

March, 1922

The Home Workshop Calendar of Timely Hints for March

\ AKE a coldframe and sash for an ‘< early start in the garden (see page 82). Overhaul the gardening equipment. Provide yourself with a wheel-hoe if you _ do not have one (see page 106). The home workshop can also assist the ' gardening plans by making plant labels and a straight-edge and measuring stick for the flower beds, and by preparing bean poles. The repair of grape arbors, garden shelters, sheds, ete., after the winter storms will also call for the home worker’s mechanical skill. Do not permit the high winds of March to find a rattling window or poorly fitting door (see page 108 of this month’s and page 100 of the February POPULAR SCIENCE | MONTHLY). As the milder weather approaches, the | gas-stove will more and more replace the | coal-range for cooking. This is, therefore, a good time to make the gas-saving device shown on page 106. The poultry yard will soon be a busy place. Eliminate waste by making self- feeding hoppers (see page 89), and, if the hens are backward in laying, try the water warmer described on page 102. See that your auto gets a good overhaul- ing for early spring use. If you are buying | a new car this season, line the hood with | asbestos, as described on page 89. The spring rains will make a poorly built cellar quite damp, but there are remedies, and they should be applied as promptly as possible. Two of them are described on page 86. This is a good time to make roof repairs, if any are needed. Get a start on the spring housecleaning, if possible, and have some of the outside painting done. Make a frame for the icebox pan to pre- vent the floor becoming damp (page 86).

Making a Wrench from a Boalt | and Two Nuts | | | By W. D. Kendrick (Awarded Second Prize in “‘Best Idea’’ | Contest for March) yaex my experience in using all kinds of tools I have found most valuable a | simple idea for making adjustable wrenches to suit the work in hand. These are made

This wrench may be improvised instant'y simply of a bolt and two nuts with the square faces of the nuts turned inside. Any size bolts and nuts can be used and | the bolts may be long or short, whichever | is more convenient. A long bolt might be desirable for reaching into a place where an ordinary wrench won’t go, and a very short bolt will be found particularly useful in tight corners where there is little room | for a wrench handle. This combination of a bolt and two nuts can also often be used as a hand vise. |

Be More Careful | of your teeth — combat the film If you are brushing your teeth in a wrong way, learn what this new way means, Authorities now advise it. Leading dentists everywhere are urging its daily use. Millions of people employ it. Make this ten-day test and let the results show you what really clean teeth mean. That dingy film Film is what clouds the teeth’s beauty. It causes most tooth troubles. Count- less teeth discolor and decay because the old ways,of brushing do not effectively fight film. Film is that viscous coat you feel. It clings to teeth, enters crevices and stays. That is what discolors—not the teeth. Film is the basis of tartar. It holds food substance which ferments and forms acid. It holds the acid in con- tact with the teeth to cause decay. Germs breed by millions in it. They, with tartar, are the chief cause of pyorrhea. Ways to end it Dental science has in late years found two ways to fight film. It has proved them by careful tests. Now they are embodied in a new-day tooth-paste — called Pepsodent—for daily applica- tion. Pepsadent REG. U.S. The New-Day Dentifrice A scientific film combatant, whose every application brings five desired effects. Approved by highest authori- ties, and now advised by leading den- tists everywhere. All druggists supply the large tubes. Dentists here and abroad now advise it. It is now bringing a new dental era to some 40 races of people. Other new effects Pepsodent brings three other effects, natural and very important. It multiplies the salivary flow—Na- ture’s great tooth-protecting agent. It multiplies the starch digestant in the saliva, to digest starch deposits. They may otherwise cling and form acids. It multiplies the alkalinity of the saliva, to neutralize the acids which cause tooth decay. Thus every use does five things which dental authorities now regard as essential. You’ll quickly see A 10-Day tube of Pepsodent is sent to all who ask. That shows the de- lightful effects. In a week you will realize that this method means much to you and yours. Send the coupon for it. Note how clean the teeth feel after using. Mark the absence of the viscous film. See how teeth whiten as the film-coats dis- appear. Watch all the effects, then read the reasons in our book. That test may lead to life-long benefits. Cut out the coupon now.

10-Day Tube Free ™ THE PEPSODENT COMPANY, Dept. 687 1104S. Wabash Ave., Chicago, Ill. Mail 10-Day Tube of Pepsodent to

Only one tube to a family

Page 70

Sia Wet RR Rp St AT ve) Shien MS. SS SAE Wt SH 2 ge seecede: me am meee ee 36 On Trial OU may now have any musical instru- ment for a week’s trial at our risk in your home. No obligation to buy. Return the instrument at our expense at the end of aweek if you decide not to keep it. The trial will not cost you a penny. Monthly Payments A few cents a day will pay. Complete musical out- fic comes with most instruments—velvet lined case, all accessories, self-instructor, etc., all at direct factory price—everything you need at practically the cost of the instrument alone. Wurlitzer instruments are known all over the world for artistic quality. Used by the greatest musicians, bands, and orchestras. Wurlitzer has made the finest musical instruments for over 200 years, Send for New Book on Musical Instruments—No Charge Every known instrument illustrated, many in ‘ull colors. All details and complete descriptions, A veritable musical encyclopedia—absolutely free! Wurlitzer has stores in over thirty cities. But no matter where you live, Wurlitzer is no farther than your nearest mail box. Send the coupon today! WuRLIIZER MUSICAL INSTRUMENT The Rudolph Wurlitzer Co., Dept. 1783 117 E. 4th Street, Cincinnati 120 W. 42nd Street, New 700 W. Jackson Blvd. , Chicago 215 Stockion St, Sau Prencncs Send me your new catalog with illustrati A ae ay = a = ec 7 e Wurlitzer i Plan. No obligation, a eeT Popular Science Monthly “ a Keeping the Home | Shipshape How to do those odd jobs that save time, temper, and money : | THE floor under an ice- box seems always to be moist or wet because the condensation of moisture on the outside of the ice-cold pan trickles down and never has a chance to dry. This can be prevented by making a frame like that illustrated from four strips of wood and two small blocks. It will raise the pan sufficiently to pro- vide ventilation all around and the dampness will dis- appear. A hand-hold cut in the front rail of the frame will Frame for Icebox Pan Minis ai ai We ant iy Sea | ~ - .. 2 make’ it easy to Lt FRAME slide out frame and niall pan.—A. E. Z. Prevents dampness _ : WHENEVER it is neces- Hints on sary to put on hard- Hardware ware of any kind, the homeworker can make the task easier by ob- serving a few kinks of the experienced car- penter. Always read the printed directions, if any have been furnished with the lock, spring, or whatever you happen to be fit- ting. Take the time to do exceedingly ac- curate work. Don’t use a pencil for mark- ing, but a sharp penknife or a scriber. The thickness of a pencil line is enough to spoil the neatness of such a job as putting in a chest lock. Be sure that such things as drawer-pulls and escutcheons are level and plumb. Give a professional touch to your work by alining the slots in the screws, either horizontal or vertical. The difference it makes in the ap- pearance of such fittings as hinges, locks, escutcheons, finger-plates, and the like, is surprising. Patented locks, sliding-door hardware, and door-checks are difficult for the home worker to install, but care and patience will go a long way toward insuring success.—A. W. : AN EXTINGUISHER of For Fire- some sort should be bil kept in the hall near F ighting the stairs on all the upper floors of the house. In case of a blaze, the stairs are the danger spot; they are the strategic line of communication which must be defended and kept open at all costs. Water is the cheapest fire-extinguisher obtainable and also one of the most effec- tive. It should be stored in the regulation 10-quart pails, painted red to distinguish them and prevent their being used for other purposes. They should be regularly re- filled once a week. The pails are so unsightly that the home worker should place special shelves for them in the hall closet, which is usually near the stairs, or, better still, he can con- struct a long, narrow closet high up on the | wall near the head of the stairs. It should be large enough for at least three pails. The way to use water in fighting a fire is not to dash the whole pail at once in the general direction of the flames. It is better | to dip a broom in the bucket and spatter the flames with water. Keeping Cellars Dry ways a source of annoy- ance, but they are not always easy to remedy, especially in clay soils. Sometimes the difficulty is due to the fact that a cement walk runs along the foundation at a distance of perhaps 6 or 8 in. from the wall, so that rainwater seeps through the earth between the walk and the wall and enters the cellar. It is advisable CONCRETE SLOPING GROUND pooracti iar ACE A t, CELLAR WALL TILED DRAIN _ LAID WITH OPEN JOINTS Two ways to run water off always to build a walk right up against the For this reason always | keep a broom near the fire-pails.—C. H. D. | Damp cellars are al- | wall and slope it well to drain water away. | If for any reason this cannot be done, the ground between the walk and the wall should be well tamped, sloped away from the wall, and sodded. To drain off excessive ground water, a tile drain should be laid with open joints, as shown, along the base of each wall. If the concrete foundation wall is fairly good, the water will not enter it, but will drain through the layer of coarse -broken stone | and pebbles into the tile and flow away to lower ground or a cesspool.—M. H. ; INDIA rubber and an Renovating ink eraser will take off such spots from wall- Wallp per paper as are apt to appear near Bear lightly on the eraser or the pattern will be rubbed off. | | tables. | Grease spots yield to a pad.of blotting- | paper held by a hot iron—not too hot an iron or the paper will be scorched. Re- | peated applications of benzine, allowing time for drying, will also remove grease spots on wallpaper. Cover a pad of cheese- cloth with bran and rub the paper with this, replenishing the bran as it drops away. Specially dirty spots, such as register the marks of children’s fingers, should be gone over with fresh bread. Allow the bread to crumble away while rubbing, so that a clean surface will constantly be used against the paper.—R. E. K. Popular Science Monthly +tof

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rthly March, 1922 nial aka —, | THE HOME WORKSHOP | Making Your Own Designs with a Camera By E. Bade | | HE home worker who is interested in in crafts of a decorative nature will find if himself constantly looking for good design | motifs. They are often exceedingly diffi- - cult to find, as professional designers can mi testify. be | Perhaps a design is needed for an orna- ld _mental border to be stained or inlaid | around a picture-frame, or it may be an - | over-all pattern for a hammered copper wi | tray, or a floral decoration for a hand- . | tooled leather book-cover, handbag, or ORTY-THREE years ago Alexander Graham Bell, the ém- er | | ventor of the telephone, wrote this inspired forecast: “‘It és H conceivable that cables of telephone wires could be laid under- 1e H ground or suspended overhead, communicating by branch wires VS | | with private dwellings, country houses, shops, manufacturers, etc., | and a man in one part of the country may communicate by word ). | | of mouth with another in a distant place.” At the right, an old print of Bell lecturing on telephony, 1877. l- | ms [> : oresig £ ‘ More than forty years ago, public requirements. It has pro- e | Fine Saeeenen Sal Gi fae diesen giketes when the telephone was still in its vided for funds essential to the 8 | experimental stage, with but a few _ construction of plant; for the pur- 7 | mirror back. How can you find an appro- wires strung around Boston, the chase of the best materials on the e | priate design? men back of the undertaking fore- most advantageous terms; for the ‘| en the three mir- You may very easily obtain original, striking, and excellent new ideas in design by using your camera, three mirrors, one plate of plain glass and one piece of ground glass. Fast- rors, which must be of equal size and without flaws, to- gether with cord into an equilateral triangle, wrapping around them a The triangular form saw a universal system of com- munication that would have its influence upon all phases of our social and commercial life. They had a plan of organiza- tion capable of expansion to meet the growth they foresaw; and their wisdom is borne out by the fact that that plan which they estab- lished when telephones were numbered by dozens is efficient training of employees to insure skilled operators; for the extension of service in anticipation of growth, with the purpose that no need which can be foreseen and met will find the Bell System unpre- pared. The foresight of the early pioneers has been developed into a science during the years which have elapsed, so that the planning | large piece of cardboard to form a tight- | fitting cylinder. The segments between the | | cylinder and the prism are filled with cot- | ton. | | | The two glass plates should be larger | Cut a strip of cardboard 14 in. wide and just | | long enough to go around three sides, | | and glue it to the of future operations has become a function of the Bell System. This is why the people of the United States have the most efficient and most economical telephone service in the world. now when telephones are num- bered by millions. This foresight has advanced the scientific development of the art of telephony to meet the multiplied . than the triangle of the mirrors. perimeter of the plates with paper to form a shallow glass box. The camera is | * BELL SYSTEM” AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES One Policy, One System, Universal Service, and all directed | | | focused on the | toward Better Service | lower corner of | | the triangle of mir- | a : BLUE PRINT READING | |) thecamera. Care 5 , | A leaf design must be taken in Cenc COUe ees te | tilting the cylinder | For trial, a sample of our New Style Copley, yn ae aanke “Gide tr Caer pe aan ‘nade. ° ° | if you send 2 cents f and i image is | ee Be a Draftsman! Earn $35-$100a week. We train you so that a perfectly triangular Book | thrown on the ground glass. The image _will consist of six smaller triangles, the | upper one being divided in half. If ' various articles are now placed in the glass box and held back of the mirrors, a design will be formed on the ground glass of the camera. Buttons give unique effects, small flowers provide floral designs, and leaves can be successfully used if they are feathered or deeply lobed. Matches give Chinese and Japanese suggestions, and paper clips make the most delicate scroll designs. Even a piece of string loosely doubled up will-produce an amazing number of decorative arrangements. quickly at home on the y a8 you study plan. and tools FREE. Write for catalog G. COLUMBIA CORRESPONDENCE SCHOOL Est. 1904 Dept. 11 Drexel Bidg. Phila., Pa. lab a stine INSTEAD OF KALSOMINE OR WALL PAPER. AY and conduc beautifies your walls—modernizes your home, and conduces to the health of your family. Alabastine is durable, sanitary,economical; forinterior surfaces, plaster, or wallboard—in full five-pound packages; directions on package; mixes with cold water. All Alabastine packages have cross and circle printed in red. ALABASTINE CO., 603 Grandville Ave., Grand Rapids, Mich. Reversible Collar Co.,Dept.116 Boston, Mass. ° ) ee ac S anne

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Ry Bent a Bonet a BERENS pope US oe

Pi eR tld Son sr e

His United Y. M. C. A. Course and the Special Coaching of his Instructor Supplied Just What he had Lacked. He is one of our Long Island students, and he writes: “I had been working at my trade 11 years but had no theoretical knowledge. Now, I am near the end of my Course and last week one of the firm asked me if I cared to take charge of running some of the jobs. Naturally, I said ‘Yes.”. The Course has done me a world of good.”’ Personal service is the keynote of the corre- spondence instruction of the United Y. M.C. A. Schools. Every student has the unlimited attention of a competent, sympathetic in- structor who takes an interest in all of the student’s problems and special needs—educa- tion, employment, business relations, etc. From the choice of a course to the last lesson, this service is unselfish and unfailing. . A Maryland student says: ‘I cannot under- stand how, with thousands of students, you can show so much interest in the welfare of each as you have shown in me.”” An Endicott, N. Y., student writes: ‘‘Your lessons contain the exact things needed by the practical man in his daily work.”’ These letters—which are fair specimens of hundreds we are receiving—show that the ‘Six Reasons” for preferring the Y. M. C. A. system of correspondence instruction are well founded. Mark and mail the coupon for these reasons and for details of the course of your choice. We will send you our booklets ‘“‘Does Education Pay?”’ and ‘‘Head and Shoulders Above the Crowd—How to Get There.”’ Our friendly counsel is free. United Y. M. C. A. Schools Dept. 8-M, 375 Lexington Ave., New York City I am interested in United Y. M. C. A. Schools’ | service. Please give me free counsel as to the position or home-study course I have marked. | — Accountant —Farm Motor Mechanics —Advertising Man —Foreign Languages | — Agricultural Courses —Foremanship —Applied Psychology —Freehand Drawing t — Architect —Highway Engineering —Auto Mechanic —Illustrator | —Banking —Locomotive Operator —Better Letters —Machine-Shop Practice t | | I 1 I 1 i — Bookkeeper —Mathematical Courses —Building Construction —Mechanical Engineer i — Business English —Plumber —Business Law —Poultry Husbandry i — Business Organization —Radio Operator | —Chemistry —Radio Engineer t —Civil Engineer —Railroad Engineering | —Civil Service —Salesman § —Commercial Spanish —Secretarial —Concrete Engineer —Shorthand-Typewriting 1 { —Dairy Farming —Steam Engineer —Draftsman —Structural Drafting | 1 —Rlectrician —Surveyor —Electrical Engineer —Tool Designing | ] —English Courses —Traffic Management —Factory Management —Use of the Slide Rule { —Farm Management —Own-Your-Home- | \ Course Name and i | CR ee ee ee (Please Write Plainly) | Complete SR oe oe LOO ee hs canis wuwwiie'd ]

—_ — ~ RAILWAY MAIL CLERKS Examinations soon. $1600 to $2300 a year. Steady life-time job. Common education wasseeseseccesssssesee Sufficient. No % ‘pull’ neces- Patterson Civil Service School, % sary. Mailcou- Dept. 163, Rochester, N. Y. ® pon for Cata- Sirs: Send me without charge your %, log.

Catalog, describing this and other Patterson Civil U. S. Government positions. % Service School ®@ Dept. 163 % Rochester EY AO) ee o N.Y. AdG@ress. <2... cove Webb b B00 0000205000008

Popular Science Monthly

THE HOME WORKSHOP Polishing-Head and Stand Made from Old Auto Parts A SMALL polishing-head and stand can be constructed from discarded Ford parts at very little expense. The stand is one half of the rear axle housing, lag screwed to the floor with the differential housing down. The top flange, against which the brake drums formerly revolved, should have four holes drilled about its circumference at equal distances. Cut out a heavy iron plate the same diam- eter as the flange and drill four holes to correspond and two larger ones in the center, as shown. Next, saw off one of the spindle bearings from a front axle, so that when it is set upon

Ol CUPS FAN PULLEY ee END OF FORD WHEEL — FRONT AXLE 00 © © ®ASE~PLATE DETAIL

DETAIL SHOWING METHOD OF FASTENING HEAD TO BASE PLATE WITH CAP-SCREWS OR STUDS LAG- SCEWS HALF FORD REAR AXLE HOUSING This rigid pedestal grinder costs little the sawed end the two bearings will be ex- actly horizontal. Drill two holes in the sawed end to match those in the center of the plate and tap them for long cap screws or studs. Fasten the bearings to the plate and the plate to the flange. Welding the joint of the bearing to the plate will make an even stronger job. A small shaft can easily be found for the polishing-wheel. Provide two collars with set-screws to hold it in the desired position. Fit an old Ford fan pulley to the end of the shaft projecting from the vertical arm of the bearing-piece and thread the oppo- site end of the shaft to accommodate two disks and a nut by which the polishing- wheel can be secured in place. Drill and tap for two oil-cups, one over each bearing. Small emery-wheels and buffers can be used on this outfit as well as afan. It will do the work of a commercial machine with- out costing nearly as much.—L. B. R.

How to Solder Aluminum T°? solder aluminum, first make a solder- ing bit from a piece of 5¢ or 34 in. round or square aluminum. Next, tin the parts to be soldered with a composition of 81 per cent tin, 16 per cent aluminum, and 3 per cent copper. After the copper has fused, the aluminum should be added little by little, stirring the mixture thoroughly all the time. The tin and a small portion of tallow should be added. Do not overheat the composition.

Boys can find many uses for old inner tubes. hey make excellent slingshot rubbers, toy airplane motors and the like. Much fun can be had in swimming with an old inner tube that will hold air.

J piso THE NEW “HUNTSMAN” KNIFE _ 54s PISTOL, ONLY ee ee he ? _ aes

— The latest—a prac- ; 9 tical pocket firearm! Easy to pai carry, absolutely safe and has a thousand uses. Not a toy, but a sturdy well- made combination knife and pistol, of finely tem- pered steel. Shoots regular .22 cal. cartridges —hard and straight. Trigger folds up and barrel locks, making accidental discharge impossible. A sure protection—always ready. American made and guaranteed. Order today at this special bargain price. Two styles—order by number. No. 214 ‘‘Huntsman,” Jacknife size, 4 inches. No. 215 ‘‘Defender,’’ Pocket knife size, 3 inches. _SEND NO MONEY unless you wish. We will mail your Knife-Pistol and you can pay the postman the above low price, plus postage. Order today! AMERICAN NOVELTY CO. 2455-57 ARCHER AVE. CHICAGO

Rail |

— PLUMBING, HEATING and WATER SUPPLY SYSTEMS Cut your cost in half Complete information in our Illustrated Catalogue ‘‘A” FREE ON REQUEST LAMPLOUGH BEAUMONT COMPANY 99-4 So. Portland Ave. Brooklyn, N. Y. SATISFACTION GUARANTEED

N wide-open water, against a head- wind an “Old Town Canoe” re- sponds instantly to every paddle stroke. In placid streams, the light- est dip of the blade shoots you for- ward. In the shallowest water, an “Old Town” floats loaded. “Ola Towns” are the lightest, steadiest and strongest canoes made. Their construction combines the old- time Indian skill with **‘Old Town” craftsmanship. All “Old Town models are built on Indian speed- lines. An “Old Town Canoe” will last for years with no upkeep. $54. up from dealer or factory—“Old Towns” are the lowest priced canoes. Make your choice from the new “Old Town” catalog. Free. All popular models illustrated in color. Write today. OLD TOWN CANOE CO. 1293 Main Street Old Town, Maine, U.S. A.

| ld Town Cances

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nthly

March, 1922 fying and the finish will last much longer.

THE HOME WORKSHOP Line the Hood of Your New Auto with Asbestos By R. A. Houston (Awarded First Prize in ‘“‘Best Idea’’ Contest for March)

doesn’t take long for a new car to lose the fresh gloss on the hood. That is be- cause the hood is subjected to great ex- tremes of heat and cold. When the hood is hot and gets wet, the finish is apt to check and crack. A simple preventive is an asbestos lining for the hood. The inside of the hood is thoroughly cleaned and shellacked and before the shellac is dry, sheets of asbestos paper, such as are used to jig cover pipes, are pasted to the under side. Acoat ™ nn of shellac is then Asbestos hood lining given the paper to make it impervious to grease and oil. In putting the asbestos on, holes should be cut out to correspond with the openings in the sides of the hood through which the air passes. This inner coat will so insulate the hood from the heat rising from the motor that there will be no danger of its becoming too hot. The results will be highly grati-

Self-Feeding Hopper Prevents Waste in Chicken-Yard { [MMSCEesARY waste of chicken-feed may be prevented by using a self- feeding hopper such as is illustrated. The weight of the hens when they jump off the feeding perches opens the feed door. When the chickens are not feeding, the hopper is completely closed. Twenty-four board feet are sufficient to make one of these hoppers. Two pairs of 6-in. light T-hinges, a few round-headed screws, a piece of heavy cord 32 in. long,

Hopper ™ details as

and a few sixpenny and eightpenny com- mon and finishing nails will also be needed. Cut the ends as shown and nail the bot- tom to them. Then nail on the back and front boards, notching the upper front board to take the cleats holding together the hinged top cover.

The feed cover is hinged and connected with the perch levers by cords passing over wooden pulleys 2 in. in diameter, cut with a keyhole or coping-saw and grooved with a file or chisel. Fasten these on with screws. The perches, % by % by 24% in., are each held by sixpenny finishing nails driven through the levers into their ends. Small weights are attached to the back of the lev- ers to serve as a counterbalance.—M. K.

The Santa Fe Special Watch A masterpiece of mechanical perfection, unapproached in its matchless time-keeping quali- ties, is NOW being sold at Leys hema greatly reduced prices. The Pres, Santa Fe Watch Co. exorbitant war time prices have passed. I want you to see the big saving in price— the easy payment plan, but most of all I want to send you a watch designed to your order—let you see it with your own eyes before Te LLIN OS Zc S ' 50 SantafeSpecial @ && LOOK 21 Perfect Jewels Adjusted to Positions Adjusted to Temperature Adjusted to Isochronism Adjusted to the Second Montgomery Dia Thin Model. All Sizes ALL FOR

you pay a cent, QL EWE OF orm The Standard Railroad Watch that is GUARANTEED FOR A LIFETIME OF SATISFACTORY SERVICE. _ These watches are now in service on practically every railroad in the United States and in every branch of the Army and Naval Service, Thou- sands of them are distributed around the world. Your name or monogram and any emblem you may desire will be engraved in the case to suit your own ideas. ; Save One-Third to One-Half the price you pay for a similar watch made by other manufactu- rers. Most Liberal Offer Ever Made. Our ““Direct-to-You"’ low Wholesale terms and Extra Special Distribution Plan is fully ex- plained in the new Santa Fe Special booklet just off the press. The “Santa Fe Special” Plan means a big saving of money to you and you get the best watch value on the market ay. Send Your Name Today Cie the coupon, fill out and receive the beauti- . ful FREE 52-page, 4-color art watch book. All the newest watch case designs are shown. Read our easy payment offer. READ the so-called secrets] of watchmaking and the jewelers’ trade—tells how we can sell Railroad watches at practically hdif the price charged by retail jewelers. READ our great “Direct-to-You"’ o*er. DON'T BUY A WATCH UNTIL YOU HAV SEEN THE “SANYA FE SPECIAL.” Watch sent for you to see without one penny down. SANTA FE WATCH CO., 380 Thomas Bidg., Topeka, Kans. Senator Capper O. K.’s Sante Fe Special

Iam glad to say that our “‘Santa,Fe Special” Watch has given entire satisfaction. I have watched it closely for three weeks and found a variation of less than ten seconds. It is cer- tainly one of the best time-keepers on the market, and I believe is the best value for the money I have ever seen. have heard many favorable com- Name ments in regard to the watch among my friends in this city. ARTHUR CAPPER United States Senator. State

Mail Coupon Today A letter, a card or this coupon will bring my autiful Watch Book FREE SANTA FE WATCH COMPANY 380 Thomas Bidg., Topeka, Kans. Please send me your New Watch Book with the understanding that this request does not obligate me in any way. ee ee ee ee ee

D for30daystrialonapproval.Your age) vt he choice of 44 Styles, colors and sizes of famous Ranger Bicycles, Factory- [i ) Bentley of Philadelphia made to-Rider lets you buy at wholesale Ay that. Hundreds ‘making for- prices, express prepaid, d dere tunes, too, with Oliver Oll-Gas QMonths toPay our Rang ' Burner. Gives3 times the heat.

r at once. Many boys and girls easily ithly

No coal or wood. Fits any gave the } mon payments. e AGENTS! Wirge stove, Burns 95 per cent. uir, 5 | ae ee territory r cent. kerosene. 1 minute to lamps, horns, wheels, parts and Special Offer at once. lemonstrate, Sells itself. No Tires equioment at half usasl oy der agents clean up—many SEND NO MONEY. Simply write for our big, {llus-@}

won inspare time. OLIVER OIL-GAS BURNER & MACHINE © catalog with lowest prices COMPANY, 2007-C Pine Street, St. Louis, Mo. | trated free Range: . a; Mead $2<¢.comesey is:

a PROFESSIONAL TONE MUSICAL INSTRUMENTS and lessons sent on free trial. Violin, Tenor Banjo, Hawaiian Guitar, Ukulele, Mandolin, Cor- net, Banjo Mandolin, Banjo Ukulele, Guitar, Banjo Guitar, or Banjo. Wonderful new copyrighted system of teaching note music by mail. Four lessons will teach you several pieces. Over 100, successful players, Do not miss this free trial offer. Write for booklet. No obligations. SLINGERLAND SCHOOL OF MUSIC, Inc., 1815 Orchard Street, Dept.135 Chicago, tlinois

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Have Traffic Laws In The Sky? ILL there be policemen to tell you to “Keep To The Right’’ or raise a warn- ing finger when you start exceeding the speed limit over New York or San Francisco? Will there be “AIRPLANE GARAGES” where one may stop for gasoline or repairs? Will the airplane be used to deliver pins or pianos? Will you step into an airplane jitney and speed down to the office in five minutes, where it now takes 30 or 35? Who can say? Anything is possible if the airplane continues to develop as it has in the last ten years. Right now, there are scores of positions open for men who are expert on airplane engines. And every year there will be more. And right now is the time to get into this business—just as hundreds of men got into the automobile business and the movie busi- ness before the rush began. Best of all, you can learn everything you need to know about airplane engines right in your own home in an hour a day of the spare time that now goes to waste. All that we ask is this:—Fill out the cou- pon printed below and mail it to Scranton. This doesn’t obligate you in the least—but it will bring fag: the full story of what the I. C. S. can do for you. —_—_————— TEAR OUT HERE — — — — — INTERNATIONAL CORRESPONDENCE SCHOOLS ox 7665-B, Scranton, Pa. Without cost or obligation, please send me complete information about the subject before which I have marked an X in the list below: AIRPLANE ENGINES CJIADVERTISING Mechanical Engineering | ()Salesmanship Civil Engineering L) BOOKKEEPING SURVEYING UCivil Service ARCHITECTURE Railway Mail Clerk Electrical Engineering Traffic Manager CHEMISTRY Business Management Stationary Engineering Cert. Public Accountant Automobiles Stenography DRAFTING Good English SII oiacce sed ctanvaseabbes boviceeskbesy vibes ssoepetanbesseenisencaumsbbeessvens ‘?) i aac ok oll bch ss abis pa sieaadcdbeceacnscvaanesahespesaeane IININ 15. si conasnescounssoveusvelieskeskepbunstepeooscesysisnsbnateseuna f; Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal,Canada, + Wireless for Everybody The Little Wonder Portable Radio Set that you saw in the “movies,” the daily pa- rs, etc. Simple to in- stall and operate. Just the thing for Boy Scouts, Campers and for use on bicycles, etc. Complete in every respect and guaranteed to give complete satisfaction. Just connect your aerial ground and phones and you are ready to receive ™ messages. Tunes to 800 meters and receives tele- graph messages within 1, mile radius and wireless tele- phone messages within 30 mile radius. 1 he gemma | Dyan ole 15 00 RADIO SERVICE & MFG CO. and instruction book)............ Lynbrook, L. I. Popular Science Monthly Constructing an Electromagnetic Pump By R. E. Nelson (Honorable Mention in ‘‘New Uses for Electricity’’ Contest) (THE possibilities for using this remarkably simple device in place of a motor to oper- ate toys and for other purposes will imme- diately suggest themselves, although Mr. Nelson used the pump only on a highly specialized machine.—THE EDITOR.]} O circulate the cutting solution on a screw-cutting lathe, the writer con- structed an electromagnetic impulse pump as shown in the accompanying drawing. A plunger operates up and down in a solenoid. Threaded into the lower end of the plunger is a small rod on the end of which is se- cured a piston fitted into a cylinder. To the upper end of the plun ger is attached a rod made from fiber or other insulat- ing material, which carries a brass ferrule to act as a cir- cuit-closer, closing the circuit through the solenoid by way of twe contact fingers. The pump operates as follows: When the switch is open, the circuit through the solenoid is open and the solenoid will not attract the plunger, which will drop until the piston strikes the bottom of the cylin- der. In this position the brass ferrule makes contact with the fingers so that when the switch is closed, the plunger is attracted upward with a quick jerk. Asit moves upward, the ferrule moves with it and the circuit is broken, but the momen- tum of the plunger carries. it up a short distance farther. The weight of the plung- —" er then causes it to fall back until the brass ferrule again makes contact with the fingers and the process is repeated in the same way as the vibration of the armature of an electric bell as long as the switch is closed. Two check valves similar to those em- ployed on oil pressure lines on automobiles are on the pipe lines. These are set ver- tically so that they will close by gravity. When the piston rises in the cylinder, it opens the check valve and draws a quan- pny. a hele A a yar This pump has only one moving part tity of liquid from thesump “ through the — i. _return — pipe; é as it descends, that valve closes and the other valve opens, and the liquid is forced upward through the delivery pipe into the tank, from which it is fed by grav- ity to the work. The pipes are or- dinary copper tubing such as used in au- tomobile oiling systems. In order that the pump may operate suc- cessfully, the following precautions must be observed: The liquid must be light bodied, for if it is too viscous, the plunger will not descend but will be supported by the liquid. The pipe to the gravity tank must be short and the plunger heavy enough to return the piston to the bottom of the cylinder. The solenoid should be capable of sucking such a plunger a distance of 2 in. Its resistance should be high enough to permit its con- nection directly across 110 volts direct cur- rent. The bore of the cylinder should not be more than 1 in. and the stroke 2 in. oe the new Home Workshop blueprints fill a real need and are welcomed by the readers of POPULAR SCIENCE MONTHLY became evident as soon as the February number of the magazine was issued. The hearty response was shown not alone by the number of requests re- ceived for the first blueprint, but also by letters indorsing the idea, extracts from two of which follow: 755 Clancy Ave., N. E. Grand Rapids, Michigan January 10, 1922 GENTLEMEN: Your -magazine is certainly fine and)just the kind I have been want- ing to get hold of for a long time. A friend made me a Christmas present of it, and he never could have given me anything that I would like better. New Blueprint Service Meets with Hearty Reception This blueprint service is great and I hope you will have all kinds of interest shown in it, as I want to see it continued. I hope to see in the Home Workshop from time to time an article telling how to handle tools to the best advantage and their proper care. (Signed) A. MONTGOMERY. Washington Junior High School Butte, Montana January 9, 1922 GENTLEMEN: If you contemplate making a per- manent mailing list, I should be pleased to have you place my name on the list, and I will forward the price of the prints as fast as they reach me. (Signed) WM. A. GATES. Fe | 4c HH fm™

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| the 1 the | the iture ch is em- biles ver- vity. & uan- quid ump the ipe ; nds, ilve | the ilve | the reed rd the pipe ank, th it Tav- the The or- pper such ling suc- st be lied, not uid. hort the The such ince con- cur- not in. March, 1922 THE HOME WORKSHOP Useful Letter-Scale Made from | Cheap Pencil Compass | _ HANDY letter-scale may be made with | a pencil compass of the ordinary | school variety, a paper-clip, and a lead- pencil. At one end of the compass the letter-clip is soldered or bound with thread Pencil forms slid- ing balance LETTER COMPASS or fine wire after being bent at right angles as shown. The readings on the hexagon pencil are determined by placing a known weight in the paper-clip. As the holder is balanced horizontally by pushing in the pencil or drawing it out of the holder, a mark is made on the pencil just at the end of the holder. written in ink at the right of each notch, forming a fairly accurate scale.—T. H Centers for Small Work ENTERS are often needed for small jobs such as testing automobile valve- stems for trueness, for pushrods that have to be dressed, and for small armatures on which the commutator must be turned = TAPER BLOCK NNW _STRAP IRON Testing with a taper block sired position, they may be locked by tightening the locknuts. A taper block will prove very handy when testing for trueness.—S. E. GIBBS. Simple Monoplane Glider OMPLETE working drawings and directions will be given in the April POPULAR SCIENCE MONTH- LY for making a glider with 30 ft. || wing spread and full airplane con- || trols. “ The glider was designed || especially for the Home Workshop and is the best all-around model that has been developed since glid- ing became a popular sport. The construction has been so simplified that the average home mechanic can easily build it at little cost for materials. The weight in ounces can then be | down. Such centers can be made by form- | ing a piece of strap iron as shown in the | sketch and fitting it with two pointed bolts. | When the centers are adjusted to the de- | N 91 o Heavier than a Good String of Fish FO you outdoor men and women, whose playgrounds are the lakes and streams of many States brought within easy reach by motor car, train or trolley—for you has been designed and perfected this lighter, more portable row- boat motor—the Evinrude “Lightweight.” Weighing not quite 50 pounds, complete—z1 pounds less than the Standard Evinrude—this new sport model is the lightest practical outboard motor made. Weight has been saved and strength maintained by replacing many bronze and malleable parts with alumi- num alloys. Practically the counterpart of the Standard 2 H. P. model in design, and its equal in power and speed, Only SOlbs ‘/ Complete the “Lightweight,” though not in- tended for such rugged service, is a motor entirely worthy of the Evinrude name. See these Evinrude motors at your sporting goods or hardware dealers. Or write for catalog and new prices (recently cut to prewar level). EVINRUDE. MOTOR CO. 632 Evinrude Bidg., Milwaukee, Wis. DISTRIBUTORS : 69 Cortlandt Street, New York, N. Y 780 Commonwealth Ave., Boston, Mass. 440 Market Street, Francisco, Calif. 211 Morrison St., Port- land, Ore EVINRUD San “LIGHT- WEIGHT’ DETACHABLE MOTOR FOR WATERCRAFT CQ —Y SS Hear the Wireless Concerts at Home from far and near. The latest news, market and weather reports now broadcasted by radio by our Government. Stations all about you 275 page No. 16 Radio Catalog—just out. Send 12c in stamps or coin for your copy of this wonderful catalog. Not sent otherwise. You could spend $3.00 for text books and other catalogs and then not have the contents of this catalog. Ever since the year 1909 Radio Catalog The William B. Duck Us Duck’s has blazed the way with everything worth-while and dependable in radio, log eclipses all previous editions, It is all other catalogs in one, No other is even half as large. The complete catalog of the Radio Corporation, with a wealth of scientific data and dia- grams, showing how to build powerful radio telephone transmitters, the Remler. Murdock, and in fact all other catalogs, are in this catalog. Over 50 pages of diagrams and data on radio. Radio Sets Cost Very Little Complete sets sell for as little as $20—some even less. Today there are thousands bringing into their homes music, concerts and news hundreds of miles away, and witha loud speaker to replace the receivers on the ears, the entire family may clearly and distinctly enjoy the entertainment. THE WILLIAM B. DUCK CO., 224-228 Superior St., Toledo, Ohio | This cata-

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92 Popular Science Monthly Ma Send No Money THE HOME WORKSHOP Amuse the Little Ones with a Cigar-Box Jumping-Jack 71 Jewel Illinois oy IGAR-BOX wood and a sharp penknife The greatest watch value are the essentials for making this amus- | ver, Oflered. | Uneaualied for ing little jump- ity. 21 ruby and sapphire " ‘ jewels—adjusted to posi- ing-jack. Make tions, temperature and parts for the isochronism, 20 year gold- front and back filled case. of the body, two Special: Silver arms, two legs, f4\, y Damaskeened Dial : $500 REWARD iinvin inex 10 Days’ Free Trial} 7 TWO HOURS WORK. nian on the Wear it for 10 Days wood and color- at our risk. Note its absolute exactness. If In answer to a request from Chief of Police, at the end of ten days Warren Biglow, the Finger Print Expert, ar- ing them before The j er you are not satisfied, just rived at the sce —— the my oy robbery of the they are cut ie jumping-jack send it back at our expense. O— Company offices. $6500.00 in currency = iia jumps Knife and Chain Free Rapes : a : We fi- bide adh cans 2 Not a single clue had been found. Bore holes in ering for a limited time this ieetiinaae gold. filled _Almost immediately Paton turned hile at- the feet and fasten them loosely to the legs knife and chain ABSOLUTELY FREE. téntion to a table which had been tipped up. . The glossy weneeney Seat an =, on " a gage age Onl 1 1 Cc a Day set of finger prints. e thief might just as an e to the well have left his calling card. gs Just send your name and address. Vay chain and ‘halle come to you, prepaid. Give the body, so that they expressman $8.50 as a deposit. {f after 10 days, all move easily. you do not —_ to a ee ya at a expense ; your de it wi refunded instant Then connect. the Trial is pie cs free. If you! ‘Keep the watch $3.40 h 1 full f $42.50 y a month until full price o' is two arms and the paid. ny en oe vere less b> lica ay ct at once /rite for your free copy of de Luxe — legs — -catalog of Diamonds and | ‘ere Address Dept. 472-H. wi cross strings ’ CAP 000 e ® Assembling the parts . 3 “The House of Quality Be a Finger-Print Expert and tiealongstring oT Pattee: - tl in Spare pert to the centers, as shown, so that a pull will L. Ww SWEE INC make the figure lift its arms and legs as if ' 1650-1660 Broadway To make a long story short, his prints were photographed, and matched with those of **Big Joe’’ Moran, a safe blower. Moran was caught and convicted on Biglow’s finger print proof. The money was recovered and a $500.00 reward given to Biglow, in addition to his fees—as pay for his two hour’s work. No more fascinating work than this—and dancing. —E. BADE. ~ big rewards go tothe EXPERT. Thousands d — s trained we now needed. The Finger Ma “$I e+ O CC rint work of governments, corporations, ° ee police Sopnstmente, detective agencies, banks, To Prevent Pipe from Tipping ne individuals, has created a new profession. ; B "Ror just one week my net profite were $164," Many experts carn $3,000.00 to $10,000.00 a NY one who smokes a pipe knows how Gt writes R.A. Moyer, He is only one of hun- year. And now you can easily learn the secret ° a5 : dreds meking big money ecting as our represen- of this new science in your spare time—at annoying it is to have the ashes spill - tative for thie wonderful new light. Burns Kerusene or Gasoline Gives 300 candle power soft, bril- lient light, restful to eyes. Costs Meyer lc an evening, Absolutely safe. (KXXA)) Lights with match. Most wonder- ful light of age—Table Lamps, Hanging Lamps, Lanterns. Big season now on. You can earn ee Moyer has. Work all or spare time. Commissions paid same day you take COMMON orders. No experience necessary. Write to- ae we day for catalog and agents FREE outfit offer. THE AKRON LAMP CO. FASTENER home. Any man with a common school edu- : ; ; ; cation can become a Finger Print Expert ina from the bowl when the pipe is laid on its short time. side. This is especially annoying to a Finger-Print Free o0ttit and Large Illustrated Book We are making a special, limited offer of a complete Professional Finger Print Outfit and a Course in Secret Service Intelligence, both ab- solutely FREE. Mastery of these two pro- fessions offers you a brilliant career. Write PAPER“FASTENER ATTACHED TO The pipe-rest i Ht ten 2 oe oe quickly for illustrated free book on Finger PIPE, PREVENTS ITS UPSETTING BENT i 1606 Lamp Bidg., Akren, Ohio Prints which explains this wonderful training nn in detail. Don’t wait—mail the coupon NOW. PRACTICAL AMATEUR WIRELESS STATIONS You may never see this announcement again, person who does any great — 4 Tee book comtaine | best apn of thirty-three Re anon’ | a s n Nn; nst n; n tin, enta University of Applied Science writing, as the ashes will invariably get a occ mepen gs installing and operating experim Desk 1363, 1920 Sunnyside Ave., Chicago over his papers. This may easily be Profusely illustrated, 136 pp. Price 75¢ ee ee ee avoided as shown in the illustration. All —_ POPULAR SCIENCE, MONTHLY a University of Applied Science : that is needed is a brass paper-fastener bent = weet oh tins ae LO Desk 1363, 1920 Sunnyside Ave., Chicago, Iil. into the proper shape.—W. W. PARKER. Gentlemen: Without any obligation what- ever send me your new, fully illustrated, FREE book on Finger Prints, and your offer of a FREE Course in Secret Service Intelli- An Amusing Mercury Puzzle ie ‘ F a steady hand indicates steady nerves, ~avame ee ee ee The bottom of a shallow cigar-box is covered with a sheet of highly glazed card- board. A small thimble (the smaller the oo better) is sunk in the wood so that its Earn J o) 0 O t em | lower edge is flush with the floor of the box. 9 5000: eee eae a } Leech es bih obese eehasaeoee ee Age... | I this puzzle will afford an amusing test. ' y Beginright. Ma —— money start. $500 month low cotinete. i aes corning Hargan of Ill. ran $ on roe Fetzer Bros, Pa. made clear cae us $3,8 .00 during first year. yp A ity Tire Co. expect 1921 peeal business to reach 0.00. Ram- say, N. D. working alone cle Santee in one And so and this on. It’s new ma- chine that does thetrick. Get into profitable business on sound footing. Learn advanced methods. Old ideas are obsolete. We teach to-date systems. Tell you how to do better a on yy work. Learn right in ies own home gh big. pomensome sonen oe schools. A go ofurthe, ip shops com- . This new, modern machine! tremendous mon- y-maker. Has wonderful prapacity f for ebuild pone re. ing casings ani tubes. ion classes of re worn. 0 “Splendid work fed ne fed Joes quickly builds trade ms oa 3 hig as ra ey ar .00 $588. 7 ginele nane handed. ui el; PARTOUT Signal Engineer Ill, says coupon for grerything 3 os ward to > know 3-4 how corn eal on to q Qualify at home in spare time for a bi ition e we P te i as Signal Engineer. "Get in this great new field Try to put the mercury in the thimble M. Haywood, Prev me peresnaliy of fascinating work where quick success, swift promotion and a high salary await you. Rail- — 5 : Haywood Tire Tire + a & Equipment Co., ae roads everywhere need men who ===. | This can be done with a knife and the card- > ghey nderstand Si 1E nd ° A electrical safety devies. RIGN, board trimmed neatly around the thimble. Book FREE "ENG ’ Sufficient mercury to fill the thimble Send opek for big illustrated ipecring ani ‘details of cor ff a] | half full is placed in the box and a sheet of r ol ‘on Ky * ‘ ° nays ¢ sete oy glass is passe-partouted on top to serve as ang Mocpanicel Drafting, Send vosta ~ acover. The object of the game is to get DEPARTMENT of SIGNA SLING, Dept 3 “ap, | the mercury into the thimble.—H. F. G. Indianapolis, Ind. ow alll ca ae oe & maolpaont Co. ra 626 Capitol Ave. indianapolis, Indiana Please send me your book telling how ican start in profitable business. Name Address Ave.

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Lonthly ‘March, 1922 AGENTS $ ; 715 THE HOME WORKSHOP Bes ‘ORES 93 How to Make a Heat Intensifier YOU CAN for a Blowtorch NON -BREAHAGLE SELL THIS FOR yg meaaal intensifier for a blowtorch may HACK GAW BLADES weve be made easily and will prove a handy FS FICA re ah, ST or pas Ta. | tool for hardening, tempering, and exper- Pe LP ~ tml Cy i LS 1k : imenting. All that I had to buy when I va att. g . == \ See made one was 2 lbs. of ground asbestos, Compare it with Ss such as is used iain oa any other blade Take it in your hands —give it a quick twist or turn that would snap an ordi- nary blade—you'll find out what Atkins has done in making a ‘“‘non-breakable”’ hack saw blade. in covering heat- ing pipes; it cost 20 cents at a plumbing-supply house. The main sup- port is made of steel or cast iron and is as high as the burner of the torch. One end is fastened to a baseboard MY! HOW THEY SELL! with one screw, permitting it to swivel. A Means ily Profit! tin can is partly cut away on one side as a oe er the or Belly Walter shown. Wire brackets are soldered to the Harris Sold 800 boxes in 6 Weeks, Profit over$100.00 bottom of the can to support the asbestos, aweek. A total retai jue . Are in at $1.75. * han Lica ACT Now! ot Mic: tet eaheen oar ‘eon. and the can is bolted to the top of the e472. ‘ A baby could sell Lucky 11. Don’t | support. delay a minute. Save time. The asbestos is mixed and plastered 7 Fro hardening and tempering A special, perfected Send $1.75 for complete outfit including display . rocess of gas and md case. At least write for circulars explaining our | around the bottom and sides of the can, oil tempering comblaed with "listed INC unique plans, including 30 other packages. Act Now. and a pocket is formed in the thickest part ateais: euiies Atkins Hack Saw Blades rk E. M. DAVIS CO., DEPT.. 1363 CHICAGO. ILL. | of the asbestos. The intensifier should be i : practically, non-breakable. Men who ck laid aside for two days to dry.—A. R. G. use them tell us they are the best cutting | blades ever made. They save time and RX A D i Oo Magnetic Tack-Driving Tool work but cost no more. re $164," OR driving tacks in places where a s ae F cee is difficult to use, the following Pr ove Its Saving A WworD TO THE tool will be found valuable. Atkins hack saw blades wili save vou INEXPERIENCED Procure a small round metal tube about time, money and labor. Prove it by 6 im. long, with an open- sending your name and address with ten P U g Cc & A S e z ing just large enough to cents for a sample eight or ten inch blace, permit the tack to slide stating the kind of material you are An inexperienced person can easily make cutting. If it is not the best blade you mistakes in purchasing wireless equipment MAGNETIZED ever used, we will send your money back. unless they insist on gre ses a rs —-- METAL TUBE. IRON ROD nized merit. Ask your electrical dealer to let 4 you see the Pacent line and you will under- ATKINS é6 KWIK-KUT 4 stand why it is necessary that you Pacentize A useful an your outfit. for res Psy a Metal - Cutting Machines The Pacent Electric Co. can supply you tight places ° TIONS with so many things that you wil need to " Give 25 % More ‘ start with, that it would be wise for you to : : , sod aren send five cents in stamps for the veakiet of , down point foremost. Other metal-cutting machines use Pacent Radio Essentials. P Inte this tube slipa about 50 i cent - the blade in erg. 3 steel or iron rod 8 in. long and slightly metal. These machines use 76° of the a N.Y. PACENT ELECTRIC CO., INC. smaller in diameter. cutting edge. Ask for book giving full oe Radio Department To use the tool, put one tack in the tube, details regarding their remarkable sav- 150 Nassau Street, New York, N. Y, place it in position and insert the rod. A “ ee. 2 Ae See | | few hammer blows on the rod will drive A BETTER SAW home the tack.—S. S. SUTHERLAND. FOR EVERY USE No matter what kind of saws or saw i Th, Drawer-Pulls for Match-Holders machinery you need—for metal or wood cutting—it will pay you to know the | ween | ITH two old drawer handles and a savings in time and labor—the increased you are a small thermometer cut from an adver- | efficiency—the longer life and greater most likely tising card, I made a useful and ornamen- value of Atkins Products. 3 SANDPAPER CALENDAR tal match-holder ae Sse = to hang beside my Send for These whenever | desk. I attached the pulls to a stiff FREE Booklets you see e pulis to a stl high grad piece of cardboard “Atkins Metal Saws,” “Kwik-Kut Th. 1gh —— by small brass Metal Cutting Machines,”’ a + paper-fasteners. Blades and Frames,” ‘Metal Banc Saw ermometer- | A strip of sand- Blades and Machines,’’ Just fill in your | j paper and a small name and address and the use you make calendar were fast- of the saw—below and mail it—NOW, VEN, Candy, Bath, Wall and Fever ened just above | Thérmometers for the home. Barome- l ith ——_——_— a oe coe - ters, Anemometers for weather bureaus, each hand e, wi ! —, pera and co-operative ob- p the age age E. C. ATKINS & CO., Inc., | et na anna —Seseesaons DRAWER PULL THERMOMETER Mounted in e | Dept. R, Indianapolis, Ind. i pressure—for physicians. WER PULL , , ’ é ; icture | Let us send you booklet on the subject Matches, thermometer middie. Bye er EG RAR rap that interests you most. may be used in Iam interested in saws for........-++++6> one camer place of the ther- | mometer.—LEIGHTON POWELL. [This design might be varied so that the sandpaper is below the match receptacle to avoid all danger of the matches being | accidentally ignited.—THE EDITOR. |} Soda cowie ee eee asee es eeVereeeeeoossen sas Taylor Instrument Companies Rochester, N.Y., U.S.A. If temperature is a factor in your produc- For Every tion, fhere is a Tycos or Taytor Tempera- | ture Instrument—Indicating, Recording, } Industry Controlling—for every purpose. 7-188 ff

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ELECTRICITY 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 good positions and get ex- perience that will give them a real start toward success in life. Good salaries are offered with rapid promotion. For 30 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 posi- tion 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. Let the I. C. S. help you. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least, and it will bring you information that may start you on a successful career. This is your chance. Don’t let it slip by. Mark and mail this coupon now. =D aoe Gee === ==TEAR OUT HERE Sm oom ae ao == | INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7664-B SCRANTON, PA. Explain, without obliga me, how I can qualify for the position, or in the oubjecte before which I mark %. ELEOTRIOAL ENGINEER OHEMIOAL ENGINEER Electric Wirin | SALES ANSHIP Lightin ADVERTISING MAN ne arene Sum Core ond Glen Polat} jeavy on >) Electrical Draftsman PAR OAD ITION Hiri aacine Desewer, | FASE STCNER P Telebh. BUSINESS MANAGEMENT ee, Private Secreta: MBOHANIOAL ENGINEER ee en Mechanical Draftsman BOOKKEEPER. Ship Draftsman Stenographer and Typist Machine Shop Practice Cert. Pub. Accountant Toolmaker Traffic Management Gas gost Commercial CIVIL ENGINEER GOOD ENGLISH Surveying and Mapping STATIONARY ENGINEER MINE FOREM'N OR ENGR CIVIL SERVICE ARCHITECT Railway Mail Clerk Architectaral Drafteman Textile Overseer or Supt. AGRICULTURE Sheet Metal Worker PLUMBING AND HEATING Navigator PoultryRalsing é R Spanish Name Present oO tion. Business Address Street and No, City. State Canadians may send this coupon to International Corr - pondence Schools Canadian, Limited, Montreal, Canada NS WN \\\ Y SS Voices through the Air You can listen to news, concerts, dance music, speeches, lectures, weather re- ports, sporting results, etc., right in your own home, by the WIRELESS TELEPHONE Our new book, just offthe press.‘‘Wire- less Telephone in Your Home,”’ ex- plains everything you want to know about wireless telephone, broadcast- § ing and also describes in detail the mod- ern ‘“‘ready-to-operate” Teceiving sets, some as low as $15 which require no E experience whatever to operate successfully, & nd 25c to share the actual cost of production, — and we will send your copy by return mail, Where's the nearest mail % AHCORWINGCO,| = 4 West Park St.Dept. S. . Newark New Jersey //}| {| Hi AUK TTT SS HWY XQ j | THE HOME WORKSHOP Strap Hinge and Angle-Iron Form Useful Door-Catch O make this cheap and effective door- catch, which will serve well in any place where a neat appearance is not essential, merely a small strap-hinge and an angle-iron are required. Curl up the point of one strap of the _ hinge and cut a hole in it as shown, a trifle | Ht! \Y/ . \/ = dd é FHINGE NAIL Fro ACT AS STOP HOLE IN HINGE ANGLE=IRON WITH END BENT UP TO RECEIVE UPPER END FILED ANGLE-IRON TO ROUNDED POINT AND BENT BACK This stop costs little and works well wider than one end of the angle-iron, which should be pointed and bent back a little. Then attach the hinge and angle-iron so that the hole in the first will engage the point of the second. Place a nail or screw under the movable leaf of the hinge to keep it horizontal.—L. B. ROBBINS. Trap for Kitchen-Sink Drain i EMOVING refuse ma- terial from the kitchen sink ah will be easier A and less un- pleasant if a cover for the drain is made as shown in the accompanying illustration. A bent up to serve as a han- dle and as many holes should be drilled in the cover as there are in the sink drain over which the trap fits —THOMAS SHEEHAN. Neat Sandpaper Blocks [aes neat ways of mounting sand- paper are illustrated. They are in- tended for the use of home workers and For sandpaperinzg fine work Popular Science Monthly RUNNING strip should be | ' mechanics who have much sandpapering to | do on small, fine work, and who therefore | require a method of attaching sandpaper to | : | a small block that will be less cumbersome | than usual.—W. C. the most beneficial exercise _ Get all the benefits of a cross country run in your own home, with SHARP’S Runathome (Trade Mark) Portable Track Just the thing to keep the indoor man fit. A few minutes daily brings wonderful _ results. Im- proved lung power, better circulation and digestion, greater activity of the liver and bowels, and rich, pure blood. Makes the body supple, graceful and erect. Devel- ops the muscles most important to health—those in the abdominal tract, supporting the vitalorgans. The ideal treatment for obesity. Avoid the stoop and lagging step of age. _ Keep well and strong with the Runathome. Simply made, nothing to get out of order. Handles adjustable to any size. Folds up compactly. Size when folded 36x 20x7. Weight, 60 Ibs. Sent anywhere in U. S. A. prepaid for $35. W. N. SHARP 65 E. Lake Street Chicago, Illinois Print Your Own cards, circulars, labels, tags, menus —, paper, a: - ° oY Presi shup. curs EXPENSE IN HALF. L OUTLAY. Pays for itself in short time. Will last for years. y to use, prin rules sent. Print for others, BIG PROFIT. Write factory TODAY for press catalog, TYPE, cards, paper,envelopes, THE PRESS CO., D-33, Meriden, Conn. “BOWLEGS and KNOCK-KNEES” i) =UNSIGHTLY v) SEND FOR BOOKLET SHOWING PHOTOS OF MEN WITH AND WITHOUT For smaller Symphonola. Styl tured and others 17c to 25c a day. of thousands giving satisfaction. Symphonolas No expensive attachments needed to “fens lay al cords. Tone natural, life ike. Well built. Highest quality equipment. No Money Down polpped anywhere in U. S. _ 30 days FREE Trial before you make first pay- If pleased take up to 2 years ” Records 70c Each - ment. cord List. tht CO tac. Lit. Desk S.P.S.M. 322 Buffalo, NY. ADD $5.00 A DAY TO YOUR PROFITS By Quicker, Cheaper and Better Work The TORIT No. 13 ACETYLENE TORCH does the biz. The latest invention for the speedy repairing of radiators, = heating, tempering, sweating, all kinds of soldering, light razing, etc. The HANDY outfit for the garage, electrician, and general repair shop QUICK, CHEAP, DEPENDABLE, and will return to the purchaser in a short while, many times its cost. Furnished complete with 4 tips, SOLDERING COPPER, tubing and connection for Presto Auto Tank, Price $7.50. Order one TODAY. St. Paul Welding & Mfg., Co. 164 W. 3rd St., St. Paul, Minn. tor be’ SY] cia ch i il i |

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nthly March, 1922 95 = THE Ne a bate ne MARVEL YOU CAN OWN OUTFIT i titi i Queen) UL a * | How to Make a Shearing Tool ; This Complete e for Sharp-Jawed Vise y run RILL a \-in. hole about 2 in. from WIRELESS | one end of a flat piece of 14 by % in. S tool steel, about 1 ft. long. The short space TELEPHONE me between the hole and the end of the steel : ) ee k STUD IN VISE-VAW SHEET METAL BEING CUT and Telegr aph Receiving 7 sou Sm e OUTFIT For ep the I % is ard a 4 " bole Designed by Mr. J. D. R. Freed, formerly Radio Engineer and designer of s Radio Equipment for the U. S. Navy during the war. arene va ' Set os — in half an 6 — hg a ot “> music, nove of ane fay. ot the Shearing \ reports of big athletic events, by wireless telephone if you are within fifty miles f f the 1 dio telephone broadcasting stations—or wireless telegraph ls, and sheet metal eimai Sennen teens stations up oe these hendoe miles away. There are transmitting blood. stations operating within hearing distance of your home. r A Complete, Dependable, e LHCKRIV patents applie Ss uarantee utht—-Ready ve p , os: summa amubehs Ciniioes ssuhons oad Wamregh Seek Goes an baleen? raceful bar is er ound toa knife edge in the manner be quickly set up by any one. No special knowledge or license is required for Devel- shown in the end view installation or operation; : receives wireless telephone, music, speeches, events Dea lers 1uscles . m " i of the day, sport-events-returns, etc., in a y mile radius o 1e P - t tations, and radio tel h signals, hundreds of miles away. , a? ant to In one comer of the vise-jaw drill and | ff ry treicatitg AINE: PHABIO RECEIVING OUTFITS arm we today | Write for Proposition ‘ee s tap a hole to ve . threaded “4-in. ng ‘ COMPLETE “MARVEL” RADIO RECEIVING OUTFIT, mode! 105 (as shown in picture above), consisting oar. Leave about 4 in. of the pin projecting. of a “MARVEL” RADIO RECEIVER, model 101 (Patents applied for), 150 feet solid copper antenna wire, 5 . Keep ® * A * h porcelain insulators, 1000 ohm telephone, leather-covered head-band, telephone cord, antenna switch, The steel bar 18 slipped over the pin wit ground clamp. code Patt. Sanitary petit apt Mee sage ge ag en = installation and operation of outfit 3 ° ¢ + + le tht t BT) GOUDIS THERESE, 2 cc ccocccndecraceesccdvogecowseuee ° “ae ee 2 ae nate ce Scarpa en, tice act orgs ses coat ode eee. veer foe 0x? jaw, which must, of course, be fairly Post C, 0. D. Bulletin C101 on request. ." MARVEL” COMPLETE WIRELESS RECEIVING '% sharp. —FRANK L. MATTER. OUTFITS (Patents Applied For) are manufactured only by the 35. RADIO MANUFACTURING CORPORATION, 251 Fourth Avenue, New York City To Cleanse Used Oil ; eee llinois ‘ ; Electric Bells Radio Hook-Ups | IL drained from the automobile crank- A complete treatise for the practical worker in installing, | In this book are shown all the best circuits for damped and wn | case and transmission may be cleansed | mostats and other apparatus used with electric bells. The transformer sending equipment,” a8 well ae vacuum tube —_ in an oil strainer that will filter the dirt to the experimenter particularly. tube menting Aiea SS ° 124 pp. Fully itustrated Price, 75 cer.ts POPULAR SCIENCE MONTHLY 225 West 39th Street New York City, N.Y. rover LOM and foreign matter from the oil and make it usable in lubri- cating springs, brakes, etc. The oil, put Price, 75 cents POPULAR SCIENCE MONTHLY 225 West 39th Street New York City, N. Y. OUTLET FOR PURIFIED OIL-, VALVE into the tank. flows down the outlet pipe and then forces its way up through the fine-wire- mesh screen shown on filter tank at the right. This screen is set Construction of Make $60 to $100 a Week Introducing thie wonderful new lamp. Gives soft, brilliant light; restful to eyes; ideal illumination. Burns Kerosene or Gasoline Clean, odorless, economical. Burns 9% air, 4% fuel. Absolutely safe. Lighte with match. 100 times brighter than wick lamps. Patented. ent of age. Table 6, lanterns. Work all or spare . You simply take orders. We deliver by Parcel Post end do collecting. Com- missions paid same day you take orders. Deafness ts ect hearing is now Te “aaee stored in every condition of deaf- ness or defective hearing from A LT YA be ess, Thickened Drums, Roaring and He ing Sounds, _ Perforat olly_or Partially WS ee, Drums,Discharge from Ears, etc. Wilson Common-Sense Ear Drums edicine but effectivel bs Mang oy ~~ def leer drums, are simple poe ; é ond S. lo experience moccssary. d which the wearer easily fits into the ons in a hoop, which now oa. Write today for catalog were ey are invisible, Soft, ea ee toes DEAT: ? permits its re- THE AKRON LAMP co. giving you full particulars and testimonials. moval for cleaning, and the cloth screen 1603 Lamp Bldg. Akron, 0. N EAR DRUM CO. WILSO »» Incorporated 422 Inter-Southern Bldg. LOUISVILLE, KY. above is also set over a hoop so that it can be changed if clogged. Style, pic. C A receptacle Ee a _ is placed under the outlet of the second Jsjetice Al re | rebhel | tank to receive the purified oil, which will an ro oral fe rise tothe top. This oil filter can be made ¢ in any dimensions. $ ; y Save 5200 to $800 is oo years A Bag for the Spare Tube ch . . Aladdin success is chiefly due to the sing steel HE extra inner tube that the motorist money saved for Aladdin Home owners. oO tic. i j “kek To: carries for emergencies should be kept a Se clean and dry. For this purpose a bag amount through eliminating ts, we made from an old CUT TUBE — 16% waste in-lum'er and alo, N.Y. inner tube will be AS SH lowering labor costs in building. Aladdin Homes are cut to fit, saving waste of lumber found very useful ; and hundreds of hours of carpenter labor. Over a hundred teautiful homes are ) ap pictdred in the Aladdin catalog. Send stamps for this catalog No. 1706 at once. eaes The old tube is = i the bs laid on a table and Sold Direct—No In-Between Profits ng, light cut a . riaaee a The Aladdin Company is the greatest home-building institution in the world and it > the illustration. does not sell through dealers. It manufactures poy Reeree at the edge of the four After cutting, the tube is folded on the dotted line as shown. The low- er portion should be turned over and cemented. An old razor- =) ; blade will cut the greatest timber-producing states. direct to the home builder. readi-cut lumber just like in any other first-class, permanent home. explains the details fully. It prepares the house complete, ready to be shipped You save the dealers’ profits. Your carpenter nails the The catalog What You Get When You Buy an Aladdin Aladdin Homes are designed to use standard lengths and sizes of lumber so that there is practica'ly no sawing, eres ys and fitting to be done by the caroenter on the job. You receive in one shipment all the timbered frame work, mill-work, the siding, outside finish, porch, shingles, windows, doors, interior woodwork, lath, glass, nails, hardware, lock sets, paints, stains and varnish. Send stamps today for catalog No. 1706, CceMENT i] Made from inner tube general rubber easily if the rubber is kept wet ; Bay City its eos with water. This bag makes a neat The Aladdin Co., Mishigns e $7.50. compact bundle, and will not chafe the on 7: hee - | Mian. good tube.—R. H. Kasper. Is; Toron Canadian Offices and Mills; Toronto, Vancouver, Winnipeg, St. John

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on triala Pair FRE of Handsome Tortoise Shell

For many years people have been coming to me _ from every part of Chicago on account of my wide reputation for supply- ing glasses that fit. I am now offering the benefit of this wide ex- perience to people everywhere. No mat- oe ter where you live, I positively guarantee to give you a perfect fit or there will be no charge whatever. I promise to send you a pair of glasses that will enable you to see per- fectly and satisfy you in every way, or you will owe me nothing. They will protect your eyes, preventing eye strain and headache. They will enable you to read the smallest print, thread the finest needle, see far or near. SEND NO MONEY I will not accept a single penny of your money until you are satisfied and tell me so. Simply fill in and mail the coupon below, giving me the simple easy information I ask for and I will send you a pair of my Extra Large Tortoise Shell Spectacles for you to wear, examine and inspect, for ten days, in your own home. The glasses I send are not to be com- pared with any you have ever seen advertised. They are equal to spectacles being sold at retail at from $12.00 to $15.00 a pair. You will find them so scien- tifically ground as to enable you to see far or near, do the finest kind of work or read the very smallest print. These Extra Large Size Lenses, with Tortoise Shell Rims, are very becoming and your friends are sure to compliment you on your improved appearance. There are no “‘ifs’’ or ‘‘ands’’ about my liberal offer. I trust you absolutely. You are the sole judge. If they do not give you more real satisfaction than any glasses you have ever worn, you are not out a single penny. I ask you, could any offer be fairer? SPECIAL THIS MONTH If you send your order at once I will make you a present of a handsome Velveteen Lined, Spring Back, Pocket Book Spectacle Case which you will be proud to own. Sign and mail the coupon NOW. Dr. Ritholz, Madison & Laflin Sts., Station C, Chi- cago, Ill., Doctor of Optics, Member American Optical Association, Illinois State Society of Optometrists, Graduate Illinois College of Ophthalmology and Otology, Famous Eye Strain Specialist. Accept This Free Offer Today —_ eee eT eee ee ee ee ee ee eee ee ee oe Dr. Ritholz, Madison & Lafiin Sts., DR-587_ Station C, Chicago, Ill. You may send me by prepaid parcel post a pair of your Extra Large Tortoise Shell Gold Fil'ed Spec- tacles. I will wear them 10 days and if convinced that they are equal to any glasses selling at $15.00, I will send you $4.49. Otherwise I will return them and there will be no charge.

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| the pen beyond

THE HOME WORKSHOP

Fitting a Secret Lock to a Box or Chest a you call this a treasure chest, a secret case, or a private box, | it will be a novelty well worth making be- cause no one but yourself will be able to | open it without breaking it apart. The box is automatically locked when the lid is closed. A small false keyhole in the inner mask ordinarily appears in the center of the slot-like keyhole in the box itself and gives the impression that a small straight key of some kind might open it. The real key, however, will not enter, until another wedge-shaped key has_ been pressed into a slot in the bottom of the box in order to move the J-shaped inner mask in such a way as to bring a slot in it | directly opposite the keyhole slot. When the key is in the lock, it is turned to the left to disengage the catch. This

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WEDGE KEY Lock mechanism and the two keys key should be made of heavy wire in the shape illustrated while the bottom key is like a wedge. The parts of the lock may be made of well seasoned hard wood or of heavy sheet brass or copper. If made of metal, extra pieces should be soldered at the edges where one part works against another. All should be perfectly smooth. The lock is assembled on a board of a size to fit neatly into the box. When it works perfectly, cut a keyhole in the outer wall of the box to register exactly with the keyhole in the inner mask, when the latter is in position for opening. Also drill a hole through the mask so that when the box is locked, this false round keyhole will show in the center of the box keyhole. The fixed latch inside the lid is not placed in position until after the lock has been | installed.—LEROY CRIGLER. .

Making an Emergency Compass HE occasion for making this emergency compass was very urgent, for the draftsman had dropped his own compass on the floor, stepped on it, and ruined

7 CIGAR-BOX Hif<~wooo —~ WAXED THREAD WOUND TIGHTS, PIN. BENT WW LINE WITH PEN a ait repair. The mishap occurred in the country, when a new part could not be had at any price. So this compass was made and the tracing was thereby finished on time.—B. R. WIcKs.

Cigar-box wood compass

| | |

Popular Science Monthly 25 Calibre Regula- tion 7-shot, lue Steel, Handsome Automatic ; accu- rate and reliable; highest grade ma- terial and work- manship; double safety attachment makes accidental dis- charge utterly impos- sible; perfect = grip; small, compact; you need this gun for your protection. Regular value $22; get one now No. 104, while they $8.75 $25 Military Medel tor $10.75 ee ‘like they used “Over There” A MAN'S gun, built for hard ser- vice. Shoots COLT’S Cartridges, 32-calibre —_ EXTRA maga- zine FREE. A 10-shot gun, regu- larly sold for $25.00. Our price NOW, for al pecan + 204, while they last. .. $10.75

Latest model; 9-shot Automatic. The World-Famous Most Powerful Weapon “sy shoots COLT’S cartridges; os fectly balanced a with ment and comfortable grip; accurate and efficient; two safety attachments; it is flat- shaped; has no sharp edges or projections and does not buige the pocket; it is solidly and simply con- structed from blue steel; can be dismantled and reassembled . é. ay seco’ Mite, $35 i: He

ro a, 3 $24.50 Cay German LUGER \ 30-Calibre 3%- inch barrel, 9-Shot Automatic, with automatic mag- azine ejector; the latest, best and most reliable pistol made. Safety attachment. Shoots American Asmunition. Regular Value $90. Our Price 30-Calibre No 904-A $24.50 ALL OUR MERCHANDISE IS BRAND NEW Order one of these Specials NOW. Mail orders prometiy filled upon receipt of cash or money order, or if you prefe SEND NO MONEY b: turn mail. You Postman on arrival. We ag 3 y sy nm =, rh coe 3 IMPORT TRADING CO. 258 Broadway, Dept 4, New York City = satis-

RAISE BELGIAN HARES Flemish Giants —New Zealand Reds, Checkered Giants, Ete, FOR US---BIG PROFITS, =ssil7,27¢P\gasantly furnish high le stock and pay 4 “$7. Oote $19.50 upward a pair and express charges for all you raise. Use back yard, cellar, barn, attic, etc. Mastasted Se Datelog FREE! ' AMERICAN HARE BREEDERS ASS'N, 188-D, Market St. Newark, N. J.

Make $35.00 to $100.00 a Week Easy oan 00 pitotna you a complete $95.00 “JUNIOR” —. Vulcanizing Outfit including _ equipment, tools, bench tools and instructions and STARTS YOU IN A $5000.00 A YEAR BUSINESS. First two weeks’ work will more than pay for your outfit. Income is continuous. Profits big. Let us start you i ~ real business of your own. to mare. Write today for all the ‘acts. | THE ADAMS BARRE CO. 11244 North High St. Columbus, Ohie

=a an

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Regular . . $24.50 ) NEW ptly filled er Full satis- ce. Easy all the s, Ohie - March, 1922 THE HOME WORKSHOP Rapid-Firing Toy Cannon Shoots Marbles HIS cannon, which shoots marbles, is a toy that is in outward appearance very realistic. It is made entirely of wood and a heavy rubber band provides the power. The missiles can be thrown from ten toa hundred feet, the distance depending en- tirely on how far down the hammer is drawn. The barrel and magazine are turned from solid pieces of wood and bored to allow free passage of the marbles. The boring stops before it reaches the breach of the barrel. Another hole is bored through from the side, meeting the first one at right angles. At this point the marbles drop in from the magazine, which is bored similarly. The hammer is less in thickness than the diam- eter of the marbles. It is admitted into the Many a mimic battle may be fought with this toy cannon i ee : non we HANGED breach through a slot just wide enough to accommodate it but not wide enough to allow a marble to drop out. The hammer pivots on a pin between two triangular- shaped pieces of wood that are fastened directly to the sides of the cannon. These pieces have holes drilled through them for the pin that secures the rubber band as well as for asmalliron bolt. The gun swings up and down on this bolt and the whole unit is fastened to the base by means of it. When the hammer is drawn back, a marble drops from the magazine into the barrel, and when the hammer is released the marble is struck a sharp, quick blow, which drives it from the muzzle. Each time the hammer is drawn down, another marble drops into place. Care should be taken not to give this cannon to children who cannot be trusted to respect their neighbors’ windows.—E. G. G. An Oiler for Your Razor-Blade A RAZOR-BLADE always works more smoothly when it is covered with a film of oil. It is easy to keep it oiled if the spout of an ordinary oilcan is cut off and fitted with a round wick as shown. Q. Bick with The blade is drawn GROOVE through a groove ON TOP at the top of the wick, which is al- ways saturated with oil. , Microscopic rust spots are almost certain to form on razor blades un- less precautions are taken to pre- vent them. The best preventive is a film of good quality oil—D.C.. Oilcan with wick W LDOUGLAS FORMENANDWOMEN $7.00 & $800 SHOES SPECIAL SHOES $1().00 W.L.DOUGLAS PRODUCT IS GUARANTEED BY MORE THAN FORTY YEARS EXPERIENCE IN MAKING FINE SHOES W. L. Douglas shoes are made of the best and finest selected leathers the market affords. We employ the high- ~ | est paid, skilled shoemakers, all work- AN | ing with an honest determination to \ de make the best shoes for the price that ; YOU CAN ALWAYS SAVE MONEY BY WEARING W.L.DOUGLAS SHOES SOLD DIRECT FROM FACTORY TO YOU AT ONE PROFIT : as i: “ie ‘ STAMPING THE RETAIL PRICE F°- AT THE FACTORY money can buy. THE STAMPED PRICE IS YOUR PROTECTION AGAINST UNREASONABLE PROFITS When you need shoes look for a W.L. Douglas store. We own 107 stores lo- cated in the principal cities. You will find in our stores many kindsand styles of high-class, fine shoes that we believe are better shoe values for the money than you can buy elsewhere. Our $7.00 and $8.00 shoes are excep- tionally good values. There is one point we wish to impress upon you that is worth dollars for you to remember. W. L. Douglas shoes are put into all of our stores at factory cost. We donot make one cent of profit until the shoes are sold to you. When you buy shoes at any one of our stores you pay only one small retail profit. No matter where you live, shoe dealers cansupply youwithW.L.Douglasshoes. They cost no more in San Francisco than they do in New York. Insist upon having W. L. Douglas shoes with the name and retail price stamped on the sole. Do not takea substitute and pay one or two extra profits. Order direct wy from the factory and save money. a STUER $500 W.L. Douglas name and portrait is the best known shoe Trade Mark in the world. It stands for thehighest standard of quality at the low- est possible cost. The intrinsic value of a Trade Mark lies in giving to the con- sumer the equiva- lent of the price paid for the goods. Catalog Free, President L. Douglas Shoe Co., 124 Spark St., Brockton, Masé. \ Be the “Tom Brown” of Your Town You may have the talent to develop into a Saxo- phone wizard like Tom Brown, of the famous Tom Brown’s Clown Band, the highest priced musical act, and enjoy this most pleasant of vocations. True-Tone Musical Instruments have helped make famous Tom Brown, ArtHickman,Clyde Doerr, Donald Clark, Clay Smith, Guy Hoimes and thou- sands of others. $500 to $1000 weekly for but two hours a day is not uncommon for musicians of such ability to earn. BOESCHE: True-Tone Saxophone It is the easiest of all wind instruments to play and one of the most beautiful. Three first lessons sent free. You can learn the scale in an hour’s practice and play popular music in a few weeks. Practice is a pleasure because you learn so quickly. You can take your place in a band within 90 days, if you so desire. Unrivaled for home entertainment, church, lodge orschool. In big demand for orchestra dance music. A Saxophone will enable you to take an important part in the musical development of your community. It increases your popularity and your opportunities, as well as your pleasure. Free Trial—Easy Payments You may order any Buescher Saxophone, Cornet, Trumpet, Trom- bone or other Band or Orchestral Instrument without paying in ad- vance, and try it six days in your own home, without obligation. If perfectly satisfied, pay for it on easy payments to suit your conveni- ence. Mention the instrument interested in and a complete catalog will be mailed free. Saxophone Book Free Tells what each Saxophone is best adapted for; when to use singly, in quartettes, sextettes, oc- tettes, or in regular band or Saxophone Band, and how to transpose for cello parts in orchestra, Send coupon below for free copy. Buescher Band Instrument Co. and Makers of Everything in Band and Orchestra Instruments Mail 3141 Buescher Block Elkhart, Indiana Buescher Band Instrument Company 3141 Buescher Block, Elkhart, Ind. Kindly mail to me Saxophone Book. Shall we also send you Free Complete Catalogue of all Buescher True-Tone Brass Band Instruments ? Clip RUMI, EOIN 050 Blain: 6.6: 6) 0! d:pin: 6 bin Kae! ebleiale sld-wielawear 2 ry | in “Tip-Top”

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Do you want to be a SURVEYOR RE you fond of outdoor work? Would you like to become a Civil Engineer? Then take up Surveying. Itis a profession that not only pays big salaries itself, but it is the stepping stone to something even better. Probably 99 out of every 100 Civil Engi- neers were surveyors first. Fill out the coupon below and let us tell you how you can pre- pare for success in Surveying, Engineering, Drafting, Chemis- try, etc., through spare-time study at home with the I. C. S. TEAR OUT HERE INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7666-B, Scranton, Pa. Without cost or obligation, please send me complete information about the subject before which I have placed an X in the list below: 0 SURVEYING (J DRAFTING {_] Mechanical Engineer’g C] Civil Engineering () ARCHITECTURE (J Electrical Engineering J Stationary Engineering (] CHEMISTRY (J Automobiles (] STENOGRAPHY (1 ADVERTISING (J Salesmanship CL] BOOKKEEPING O Civil Service CT Railway Mail Service () Pharmacist ( Traffic Manager C) Business Management LJ Cert. Pub. Accountant C Airplane Engines Occupation WE TEACH COMMERCIAL ART Properly Trained Artists Earn $100 a week and up. Meyer Both College—a Department of the Meyer Both Company—offers y ou a different and practical training. If you like to draw, develop your talent. Study this practical course—taught by the largest and most widely known Commercial Art Organiza- tion in the field with 20 years’ success—which each year produces and sells to advertisers in the United States and Canada over ten thousand commer- cial drawings. Who else could give you so wide an experience? Commercial Art isa business necessity—the demand for commercial artists is greater every year. It’s a highly paid, intensely interesting profession, eaually open to both men and women. Home study instruction. Get facts before you enroll in any school. Get our special klet, **Your Op- portunity’’—for half the cost of mailing —4c in stamps. MEYER BOTH COLLEGE of COMMERCIAL ART Michigan Ave. at 20th St. Dept. 35 CHICAGO, ILL. THE HOME WORKSHOP How to Make a Combined Muffler and Car-Heater TARTING a car in cold weather is especially hard on the muffler and sometimes muffler shots demolish the muffler shells. An arrangement that is not easily damaged unless through a collision or accident may be made by assembling short sections of pipe such as are used by plumbers for waste pipes, fairly thin-walled. These can be connected with couplings and ta FLOOR-PLATR CAR FLOOR TAIL: PIPE. _s ee so SECTIONAL VIEW PERFORATED FLOOR-PLATE SHEET-IRON BOX 15 PIPE AND FITTINGS "vam PIPE me ee ee we eee eee 7 rm ' This muffler also warms the car secured on the end of the exhaust pipe to replace the muffler. Six or eight sections make a muffler as efficient as the usual type bought. An advantage afforded by the use of these pipes, as shown in the illustration, is that the heat may be directed into the car through a perforated cover. This arrangement does not encroach upon the foot room, and in the summer the perforated section can be covered with a piece of sheet iron and the sheet-iron box cover about the improvised heater muffler removed to avoid unduly heating the floor.—G. A. L. A Neat Glass Holder HIS glass holder was made with one end of an old towel-rack, a section of cur- tain-pole, and an aluminum can cover. The cover was fastened to the wood with three brass nails. Water can be removed from CAN-COVER BRASS NAILS CURTAIN-POLE END OF OLD TOWEL~RACK Holder made from odds and-ends support.—D. W.C. Save Your Hands with Soap the cuticle, and under the fingernails. you will be ready for work. be cleansed. tion.—F. W. ERDMANN. | j Gt? am, PIECE OF WOODEN the cover by lifting the holder off the rod | HEN about to do painting or any dirty work, you can protect your hands by a simple method. Moisten com- mon soap and work it into the pores, around In about a minute your hands will be dry and After the job is done the hands can easily I have made use of this ap- plication for many years while working on my automobile, and as a result have always kept my hands in good condi- Popular Science Monthly Y WIRELESS TELEPHONE] BROADCASTING stations operating on a regular schedule now reach practically every section of the country. 4/ This book explains how you can enjoy the modern romance of wireless. _Its title is ‘‘How I Fut Upa Complete Radio Receiving Station in Two Hours,” —a true story by a young man with no previous experience whatever. It also describes in detail ABC sectional receiving UNITS. (Complete receiving station ready-to-operate, including phones, aerial wire and all accessories, only Send ten cents for your cope today. Request Booklet C3. WIRELESS EQUIPMENT CO., Inc. |; Newark, New Jersey Convert Your Bicycle Into a Motor Cycle with aSTEFFEY ATTACH- MENT. Fits any ordinary bicycle. Easily attached. 4 PRACTICAL—ECONOMI.- CAL—RELIABLE. Send stamp fer circulars. STEFFEY MFG. CO. Dept. S, 5025 Brown St., Phila., Pa. PATENTS Send us sketch or model for patentabilit ,upinion and exact cost of patent. Our book How to in a Patent” Sent Free on re- quest. It tells how to apply for Patents, Trade Marks, F Patents, Cop: hts, etc.; gives information on Patent Procedure; tells what every inventor should know. Th ds of I 's, who are our clients, are our references. CHANDLEE & CHANDLEE, 25 Years' Experience 427 7th St. Washington, D. C, (ws Wecan teach you A“ DBAWING \ ve i ‘ nm your own t home dur- - ing spare Our 23 years of success- ful teaching prove our ability.-. 10 Courses inCom- mercial and Illus- trative Drawing : Endorsed by high art authorities. Students trained by members of 45 our Faculty are filling high-salaried FREE positions. Ttist’s Outfit FREE to Enrolled Students. x Write today for Art Year Book. SCH@1LAPPLED ART ROOM No. 8 BATTLECREEK MICH. ~ F ree Music with the Radiophone Receiver j Listen to music, speecties, lectures. Get time J signals, sport and political news, weather and crop reports, before released by the press, as sent out daily by radio telephone stations. No ff knowledge of radio or code required. Instruc- ff ‘ion and entertainment for the whole family. is designed to receive all radio telephone broad- casting stations, as well as commercial and amateur stations. Made of finest materials; walnut finished case; weight 5 lbs. No mast required. Price $25.00. Aerial equipment $6.50 extra. Can be installed in 30 minutes. Satisfaction guaranteed. Send for catalog. Dealers investigate. DeForest Radio Tel. & Tel.Co., 1395 Sedgwick Ave., P ew York

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March, 1922 _strap iron or heavy galvanized iron is , the motor pulley; | frame approaches, repeat the process. | and a drill can be are exceedingly satisfactory.—H. G. THE HOME WORKSHOP Electric Machine for Making Photographic Prints Rapidly i one is pressed for space, lacks time, and often has to run off large batches of photographic prints, this machine will be a money-saver. When properly set it will also insure more uniform printing and fewer discards. The printing-frames drop into slots in a revolving disk of wood, which should be about 2 ft. in diameter for handling post- card sizes. A small motor turns the disk and presents each frame in turn to a frosted 40-watt bulb. Variations in speed may be made by changing the lamp or placing a larger pulley on the motor. The disk is made of several boards cleated together and cut with a keyhole saw. The SUSPENDED gi ll KEGCOVER oR PRINTING-FRAMES Each revolution makes four prints spaces for the frames are then cut at equal distances apart in the edge and a piece of nailed around the rim. The motor pulley should not be more than \% in. in diameter, unless the motor runs slowly. The guide pulley prevents the belt, which is stout cord, from jumping off without it, the motor would have to be farther from the machine. Strips of sheet iron are fastened to the printing-frames with screws as illustrated, and a screw-eye may be placed in each to serve as a handle, provided it does not in- terfere with the driving-cord. To operate, start the motor, turn on the light, and remove from the disk the frame that is approaching. Place negative and paper in it and drop it back in its slot, which should not have traveled more than one sixth of a revolution. As the next The baths must be prepared beforehand and it will be well to have a rinse bath with running water, or, better still, have a helper to take the prints after coming from the frames. This will prevent developer getting on the unexposed paper. As the operations become mechanical, the speed may be increased.—DALE R. VAN HORN. Drilling Deep Holes in Wood SMALL twist drills are easily broken when used for boring deep holes in wood. When it is necessary to do drilling of this nature, it is better to make up a set of drills of plain steel rod, not hardened. The rod is cheap BEVELED CUTTING EDGE Gill! LONG STEEL ROD FILED: FLAT AND POINTED The drill paints made in a few minutes by sim- ply filing or grinding the end flat and pointingit. Such drills do not make as clean and smooth holes as the regular drills and they are good for wood only, but for this special purpose they TRADE-MARKS AND COPYRIGHTS ATENTS comviticnrs: SP ECIAL OF FE PATENTABLE NATURE Before disclosing an invention, the inventor should write for our blank form ‘*Record of Invention.’’ This should be signed and witnessed and if-returned to us together with model or sketch and description of the invention, we will give our opinion as to its patentable nature. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK HOW TO OBTAIN A PATENT Contains full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illustrated and de- scribed, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, fy, and Law Points for inventors. OUR TRADE MARK BOOK Shows the value and necessity of Trade-Mark Protection and gives information regarding unfair competition. OUR FOREIGN BOOK We have Direct Agencies in all Foreign Countries. Write for our illustrated Guide Book on Foreign Patents. Send for List of Patent Buyers containing unsolicited Letters from Manufacturers and others Wishing to Buy Patents. SPECIALIZATION Our Staff The field of invention is so vast that it is impossible for any one to become an expert in all the different classes of invention. Only those skilled in the class to which the invention relates are capable of rendering efficient service. For this reason Victor J. Evans & Co. employ a number of patent lawyers and mechanical experts who have been selected for their special knowledge and ability in certain lines of invention. Each case is placed in charge of experts in the classes in which the invention relates, THE VALUE OF YOUR PATENT Will depend much upon the skill and care with which your case is prosecuted in the United States Patent Office. We spare neither time nor pains to secure the broadest possible patents that the inventions will warrant. That every case entrusted to us receives our best efforts, and that our work is done consistently, skillfully and thor- oughly is evidenced by the many unsolicited letters of commendation that we receive constantly from our clients. We will furnish upon request lists of clients from any State in the Union for whom we have secured patents, Our New York, Philadelphia, Pittsburgh, Chicago, and San Francisco Offices Owing to the growth of our business we have established for the benefit of our clients Branch Offices in New York Citv , Philadelphia, Pa., Pittsburg, Pa., Chicago, Ill, and San Francisco, Cal. These branch offices being located in these large commercial cities, together with our Main Office located near the U. S. Patent Office, in Washington, enables us to more promptly handle the business of our clients, par- ticularly as the branch offices are in constant touch with the Main Office and fully equipped to handle patent business in all its branches. Highest References—Prompt Attention—Reasonable Terms (CLOT woe ee ON eed = Wi ith vi Mi 2 pai 2 His? ml Patent Attorneys New York Off Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 135 S. Broad Street 514 Empire Bldg. Chicago Offices. 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. Main Offices, 760 9th Street, Washington, D. C. Gentlemen: Please send me FREE OF CHARGE your books as described above. } ee eee ee eerereereeeeeeeeees VICTOR J. EVANS & CO.

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100

Popular Science Monthly

ATENTS P

etc. will give! our opinion as to its patentable nature. RANDOLPH & CO. t i & 130 F St, N. W., Washington, D. C. : IF YOU HAVE AN INVENTION and DESIRE TO SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. Tells our Terms, Methods, Send model or sketch and description of your invention and we cerns LEARN HOW TO SOPOT OEE SOOO SESE EEE HE SO HH He eee®

CREA SPOR

¥) Our

LAXO TRICK CO.DEP.X-K NEW WE GIVE The BEST and MOST for

aN a HALAS TRADE-MA Beale & Par Inventors and M gives those facts ; free. Write Lacey &Lacey, 639L F St. Washington D.C bss ESTABLISHED 1869 PATENTS who derive largest profits know and heed certain simple but vital facts before applying for PATENTS

book Patent Sense. for an acturers, RKS COPYRIGHTS Send for our free book of patent information 804 F St., Washington, D. C. 16 S.Broad St., Philadelphia, Pa.

PATENTS Booklet Free Highest References Promptness Assured Best Results Send drawing or model for preliminary

Patents C. A. SNOW & CO. Send model, sketch or cost of Patent, etc. marks and Seer ente free. Cc. A. SNOW & CO United States Patent O

Patent Business Exclusively Since 1875 hoto for free advice, on Patents, Trade< Write or come to «+ 710 8th St., opposite fice, Washington, D.C. Boo

examination of Patent Office records and report as to patentability

All Business Given Prompt and Proper Attention WATSON E. COLEMAN, Patent Lawyer. 624 F St., Washington, db. Cc.

DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CON- CEPTION” to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up your evi- dence and establish thesame before filing ap- plication for patent. As registered patent at- torneys we represent hundreds ofinventors all over the United States and Canada in thead- vancement of inventions. Ourschedule of fees willbe found reasonable. ‘The form “Evidence of Conception,”’ sample, instructions relating to obtaining of patents and schedule of fees sent upon request. Ask for them,—a postcard § will do. PATENTS AND \ TRADE MARKS 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘Evidence of Conception.”

PATENTS Secured Prompt Service. for our “Record Book telling How to Obtain a Patent. sketch or model for examination. advice without charge. Highest References. Write TODAY. J. L. Jackson & Co., 246 Ouray Bldg. Washington, D. C Send Free Send Preliminary Avoid dangerous delays. of Invention” form and

tions? tions and We help our clients, PATENTS sia ADVERTISED one others possess. | For SALE FREE can foam, In INVENTION And book at once, "MM MANUFACTURING SUPPLEMENT. AMERICAN INDUSTRIES, INC. 201 Patent Dept., WASHINGTON, D. C. ecription 50c. think of a simple, practical idea that will fill one of the many ree quests we have on file for new inven- Thousands of things are needed RiGut Now. Your brainscan help. Send to- day for our great new book—“‘Invene - Protection and _ Exploitation’’ money from ideas than you ever knew before. things that are wanted,

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It may mean a fortune for you. and Trade Marks, Their learn more about -making It tells many too. A postal will do— Published for the man with an idea. Send for free sample copy. One year’ssub-

THE HOME WORKSHOP

How to Make Your Own Self. FTEN the expense of having a rubber Inking Stencil Stamps O stamp made may be saved by making

stencil stamps on your own typewriter, | They are easily prepared after you have | provided yourself with a holder. | Select an ordinary rubber-stamp holder | with a flat, smooth face if possible, although

STENCIL STENCIL READS BACKWARD SOLDERED A stencil takes the place of type

the channel type will do. Cut pieces of flannel and linen or muslin to fit over the face of the holder and bend a strip of 3¢-in. wide tin or brass to form a collar for clamping the cloth and stencil to the frame. Solder the ends together. The flannel is placed on the holder and inked uniformly with a regular mimeo- graph ink, and the linen (or muslin) piece is laid smoothly on top. Then make a mimeograph stencil on the typewriter in the usual way and fasten it to the holder with the collar. After any excess of ink has been wiped off with a slightly dampened cloth, the stamp will make good, clear im- pressions.—L. POWELL.

Bracket for Horn-Button HE horn-button on a Ford or those on other cars are readily made more access- ible by means of the simple attachment shown in the illustration. This attachment consists of a section of thin brass or steel pipe cut open at the ends and fastened to the steering-post by means of the clamp thus formed. The length of the bracket

BUTTON, CLOSE TO INDEX FINGER : Va j SAW SLOTS | SS ( = VIEW : : ¢ FACE FOR { HORN BUTTON

"SIDE VIEW BRASS OR STEEL TUBING How bracket is made and attached extension should be about 6 in. so that the index finger of the right hand can reach it while the palm of the hand is on the steer- ing-wheel. The pipe is split open with a hacksaw and the ends are spread. A stove- bolt clamps the bracket to the post. Two holes drilled through the other end are for screws to secure the horn-switch. This bracket is adaptable to either a circular or oval post and is adjustable sidewise or up and down to the position most essential for quick operation.—G. A. L

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onthly lf. bber king riter, have older ough i Ni Je i i i ee — March, 1922 THE HOME WORKSHOP Novel Method of Belting Small Machines for Two Speeds HE accompanying picture illustrates a novel method of speed changing. The drive pulley is wide enough to accommo- date two belts and still leave a blank space between them wider than the width of the belt. Two small pulleys of equal size and two large pulleys of the same diameter are placed alternately on a short shaft. The two belts on the drive pulley lead to two of the pulleys on the short shaft, leaving a pulley between them, which is belted to the machine. One pulley on the short shaft always runs minus a belt. The drawings show two arrangements to drive the machine at two different speeds. DRIVING PULLEY =z ——_— \_W AM SS INTERMEDIATE PULLEYS aa i NE HIGH SPEED Low SPEED The belt lengths are unchanged The intermediate pulley virtually re- volves in the air, as the pull of the belts retains it in position. Should a belt break, the balance is destroyed and the pulley wil! fall. For this reason it is well to furu.- safety guards. These consist merely oi tw» strips of wood in which the intermediate shaft revolves freely. The ends that pass over the drive-shaft should be slotted to permit the intermediate pulleys to change their position. This method is not recommended for heavy work, but it is effective for light driving.—R. H. KASPER. Copy- or Proof-Holder HIS copy- or proof-holder was found to be very useful in a lithograph shop. It is quicker than the thumb-tack method of fasten- ing copy and also replaces the usual makeshift easel, which is always in the way. It would be valu- able in any work- shop for holding drawings. The construc- tion is so clear in the drawing as to be self explana- tory. A piece of old clockspring or other flat spring holds the clip closed.—D. W. CLARKE. PIECE OF CLOCK*SPRING A useful clipboard LR AK AR A AR IK AR IR ARR IR AR I II I I IR TI AK OK TOI OAR AK A AR AA JAAR A IA A AA AA AR AR AR SAS i AR} GOGO 8 Pi GG POG FP G'9' DGG) 9'F'O' O'D,: Inquiries from Manufacturers and Others Who Are Looking for Good Ideas PROTECTED BY PATENTS are constantly being received. Manufacturers are always in- terested in any new device for which there is a market, which fills a long felt need, which makes production possible at a lower cost, or which will do the work BETTER. Extracts from some of the more recent letters received are printed herewith. There is undoubtedly a great demand to-day for really worth while inventions. Your First Step If you have an idea, send immediately for my blank form “TO RECORD YOUR IN- VENTION.”’ best interests by filling out and signing this form before you disclose your invention TO ANY ONE. This document will help you determine and establish evidence of in- vention before filing an application in the U. S. Patent Office. A copy, with full in- structions, will be gladly sent free on request. soox “SUCCESSFUL PATENTS’ Every man who has an invention, or ever hopes to have one, should send for a copy of my book, “SUCCESSFUL PATENTS.”’ everyone should know about patents, trade-marks, copyrights, etc. It describes my methods, fees and terms, gives information relative to assign- ment or sale of rights, and instructions in detail. for a’free copy of this book—or a postcard request will do. To the Man with an Idea I offer a comprehensive, experienced, efficient service for his prompt, legal protection, and will endeavor to aid him in the commercial develop- ment of his proposition—my service is distinguished by over 12 years’ successful practice, and by thousands of satisfied clients and by reason- able fees. Send sketch, or model, and description, for advice as to cost, opinion Preliminary advice gladly furnished as to its patentable nature, etc. without charge. esgeuaeeeevoevceewoameweCOUPONe © @ = ew ew ew see ee eee ow RICHARD B. OWEN, Patent Lawyer Main Office, 6 Owen Bldg., Washington, D. C. Branch Office, 2276-D, Woolworth Bldg., New York City Please send me, without charge, or other obligation, a copy of your book, “SUCCESSFUL PATENTS,” your form “TO RECORD YOUR INVENTION,” and information concern- ing patents, etc. You should serve your own - COCO OOOOH HEHEHE HEH HHH HEHEHE EE 101 Can You Help? Here are abstracts from a few recent requests I have received from those who wish to buy, finance or manufacture good inventions. Have you an idea that will fill the bill? Following is an extract from letter dated July 20, 1921, from a middle western manufacturer whose volume of business last year was approxi- mately $1,000,000. “If you are in touch with any meritorious proposi- tion seeking manufacturing facilities, in the automotive or some other g field, we shall be glad to have you place us in touch with it. We are willing to consider outright purchase of patents or manufacture upon a royalty basis.” Another request from a large cor- poration, dated June 27, 1921, follows: ‘Should you have clients whose in- ventions are worthy commercial manufacture and exploitation, we shail be glad to consider the financing of such projects, if they are interesting. In that event, we indicate also that we are identified with two large machin- ery manufacturing plants located, respectively, in Bridgeport, Ct., and Providence, R. I. These plants, be- sides having their own foundries, are thoroughly equipped to manufacture anything from a small lathe to a com- plete automobile. Whether your clients have mechanical inventions or otherwise, we shall be pleased to hear of any proposition requiring financing.” Another letter dated April 28, 1921, from a large corporation whose officers include some the best known men of the country, says in part: ‘“We are in the market for an invention of merit epossessing undoubted economic and peewee: value combined with ADEQUATE PATENT PROTEC- TION.” SENT FREE It tells what Mail coupon to-day iy oY VY i om Wy un ~~, ; FPO PP OPED LPL IFIO CE eb X botnet khan dh tk._%X Xi XY YY WY yy YN YY SY Wh ree ‘@'

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The Musical ,one of waudeville’s great- est hits all play Conn instruments Billy Markwith and *‘Brown’s Saxophone S ‘od all use and ead Conn S b Easy to Play, for Pleasure and Profit F you are interested in music for the joy a playing, the Conn saxorkcne is the instrument for you. Its exclusive feat- ures make it so easy to master that you can learn a tune in one hour; play all popu- lar music after brief, fascinating practice. Besides, saxophone soloists, trios, quartets, sextets, like those pictured above, are in great demand for all sorts of entertain- ments. You can make big money “on the side” or playing whole time, as you choose. Free Trial; Easy Payments, on any Conn instrument. Everything for the band and orchestra. All exclusive Conn features at no greater cost. Send coupon for details. 332 Conn Bldg. New York Conn Co., 233-5-7 W. 47thSt. Agencies in All Large Cities. Elkhart, Indiana Free Books New Saxophone Book, tells how to use saxophones in trios, quartets, etc., and ex- “ng superior features of nn. “*Success in Music and How to Win it,”’ by John Philip Sousa, tells opportunities with all band and orches- tra ins ents. Send coupon, checking book you desire free. -eeeee ee is C.G Conn, Ltd., 332Conn Bidg, Elkhart, Ind. and details of free trial of any instrument. E Name Street or Rural Route _........... se eet County.. State Please send Saxophone Book ( ) or Success Book, ( | Instrument THE HOME WORKSHOP Small Electric Lamp Warms Water for Poultry No only should drinking water intended for poultry be kept from freezing so that the hens can drink at all times, but, according to scientific poultry-raisers, it should also not be cold enough to chill the birds. Both requisites may be provided for by the use of this inexpensive electric water-warmer. An ordinary pail or pan may be used with the addition of a large tin can or small pail for the heating unit. If made of galvanized iron, the parts will last longer. Warm drinking water often means more eggs Arms riveted to the can extend over the edge of the water-pail. Care must be taken to solder around the rivet holes on the out- side, for the lamp-container must be water- tight. An ordinary metal lamp socket is | soldered or crimped into a tin disk large enough to cover the container. This cover must be either a tight-fitting lid or be made to fasten with a spring or catch. In all but the coldest weather a 15-watt lamp will warm a 10-quart pail sufficiently. Operating 24 hours a day with current at 10 cents a kilowatt hour, the warmer will cost 3.6 cents, which is worth while if it adds only two eggs a day to an otherwise doubtful cold-weather production. In severe winter weather, it may even prevent the loss of some of the hens.—J. H. V. A Vise for Carburetor Bowls Wee holding carburetor bowl, muffler shell, speedometer heads, and like thin body stock, I use a pair of giant gripping hands. These are made of two pieces of hard wood 3 by 4 in. and a threaded eye-rod PIVOT BOLTS BOLT AND EYE HEAVY HARD WOOD BENCH This clamp grips firmly without damaging and nut for the gripping screw.’ The two pieces are bolted to the top of the bench so that they can be swung back out of the way when not in use, by removing the nut from the eye-bolt and sliding the rod out of one of the pieces.—G. G. MCVICKER. Popular Science M onthly Electrician’s Wiring Manual Tools and Symbols—Preliminary Suggestions on Building Wiring— Moulding—Flexible Conduit—Rigid Conduit—Fixtures and Their Instal- lation—Switches—General Sugges- tions on House Wiring—Installing Household Electrical Utensils— Wires and Cords — Motors —Transformers —Switchboards and Panels—Motion Picture Theater—Bell Circuits, An- nunciator Circuits, Gas Lighters, Burglar Alarms, Bell Transformers, Door Lock—Elevators—Wiring in Damp _ Places—Outside Wiring— Grounding and Ground Detectors— Inspector’s Report on a_ Defective Electrical Equipment — Estimating and Specifications—Tables and For- mulas—Electrical Circuits, Calcula- tion of Wiring, Line Losses and Na- tional Electrical Code Discussed for the Beginner—Alternating Currents Simply Explained—Some Things ‘the Electrician Should Know About Storage Batteries— Underwriters’ Re. quirements in the Installation of Wireless Telegraph Equipment— Practical Kinks. There are many formulas and tables which are of great value to the electrician. This is a book every wide-awake electrician or any one who wishes to do any wiring should own. Don’t take chances, but be sure your work will pass the fire in- spector. This Manual may save you 100 times the price of the book. 448 Pages, 414 Illustrations, Hand. some Flexible binding. Pocket eise. Pirce, postpaid, $2.50. Popular Science Monthly 225 West 39th Street, New York We will train you to write show cards for us. vassing or soliciting; wesupply you with steady work; distance no object; will pay you from $15 to $50 a week, WILSON METHODS, Limited Dept. C 64 East Richmond, Toronto, Canada No cane MOTORCYCLE BARGAINS SAVE 257% to 65% on Slightly used and Rebuilt Motor- cles, le Cars, Johnson Motor is, Evans Power Cycles, Bicycles. Send for Free Bargain Bulletin and Money Saving Message, listing hun- dreds of Bargains in used, rebuilt and new machines,supplies, a es, etc. AMERICAN MOTOR CYCLE CO. Dept. 302, 2047 W. Chicago Ave., CHICAGO WHY DON’T YOU Write the Words for a Song? You can do it. Write about Love, Mother, Home, Comic or any subject and send poem to me at once. I compose Music and guarantee publication. EDWARD TRENT, : You can read music like this quickly iN YOUR HOME. Write today for our FREE booklet. it tells how to learn to play Piano, Organ, Violin, Mandolin, Guitar, Banjo, ete. Beginners or advanced players. Your only expense about 2c per day for music and postage used. AMERICAN SCHOOL of MUSIC, 32 Lakeside Bidg., CHICAGO 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 stopped Head Noises, and will do it for you. They are “Play 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. 4. O. LEONARD , Suite 301, 705th Avenue - - New York Cit» 631 Reaper Block, Chicago — March, 1 MEI Earn U Big de nating, opport official Pleasa with e: spare-t can ea If, aft secure a mor ment | Don’t bookl

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March, 1922 BE; A RAILWAY RAFFIC INSPECTOR MEN WANTED! POSITION GUARANTEED Earn Up to $250 per Month, Expenses Paid. Big demand for trained men in this fasci- nating, new profession. Many splendid opportunities thru contact with railway officials. Travel or remain near home. Pleasant, healthful, out-door work. Start at $110.00 per Month with expenses paid. Prepare-in three months’ spare-time study at home. Any average man can easily qualify. Position GUARANTEED If, after completing preparation, we do not secure for you a position paying at least $110 a month and expenses, we refund your enroll- ment fee in full) YOU TAKE NO RISK.

Don’t Delay—Investigate Now. Send for free booklet No. D-588 today Standard Business Training Inst.

For 67 years these little marchers have led band instrument buyers to better quality and valuel FREE—84-Page BAND CATALOG Pictures describes, prices everything for the band—from slngie instrument to wath sold by loeline meaieerhantsoverrtete free tria, Ba 0 et payments State £ LTercrened ta Wits for Hook today LYON & HEALY,72-97 Jackson Blvd., CHICAGO

a MOTORCYCLE & GILYCLE PARTS, ALLESSORIES, TENNIS GOODS, LAMPING EQUIPITENT CHILDRENS VEHICLES, FISHING TALHLE . Send us your name for our 1922 72 page Illus. Catalog No. 3. It saves you the middleman’‘s profits of 10 to22%e GOTHAM S"ORTING GOODS CO. 127 Ci1ambers St... New York City

Dollars in Hares We pay $7.00to$18.50 and upa pair and express charges. Big Profits. We furnish guaranteed high grade stock and buy all you raise. Use backyard, barn, cellar, attic. Con- tractand Illustrated Catalog Free. STANDARD FOOD AND FUR ASS’N 407C Broadway New Yor

%. Nerve-Wracki eee

NS . » Have a bottle of Sloan’s Liniment handyin case of sudden attacks of rheumatism, neu- ralgia, sciatica or lumbago. Also good for lame back, sprains and strains, over-worked and sore muscles, Penetrates without rubbing. Sold by dealers you know and can trust, 35c., 70c., $1.40, Keep it handy 9 Sioa Liniment

THE HOME WORKSHOP

Ornamental Table Fountain Does not Require Running Water HIS self-acting fountain, which will play for a long while without attention, makes a novel table decoration. Two tanks of the same size and a basin that holds rather more water than either are combined as shown. The arrangement of the pipes can easily be followed in the

Wn. PIPE CX ZAR?

ight TANK

TANK

[> = =~ An adaptation of Hero’s fountain diagram. The pipe C has only a very small hole in the top. To operate, put a plug in the top of pipe A, take out the basin plug, and fill the upper tank. Replace the plug and fill the basin also. Pull out the plug in pipe A, and then the water will rush down that pipe into the lower tank, up through pipe B into the upper tank, and finally up through pipe C, falling in a spray. The process will be re- peated automatically. The fountain may be provided with any suitable ornamentation in plaster, wood, or metal.—E. A. MCCANN.

Increasing Wrench’s Capacity E tgr usual adjustable wrench supplied in the average automobile tool-kit is of too limited capacity to turn large couplings or nuts, as on the exhaust pipe, or water- pump glands, and similar parts. To avoid carrying more tools and to save the cost of extra wrenches, one motorist altered the adjustable wrench in his tool- kit in the manner illustrated. He drilled a CAVA ian" PEEN OVER This wrench has wide range

NG he <5 \ ADJUSTING SCREW ROUND HEAD BOLT AND PIN REMOVED CUT AS REQUIRED hole in the handle and inserted a round- head bolt, with the sides of the head cut flat, so that the adjustable jaw of the wrench could bear against them when the adjusting screw had been temporarily re- moved. On some wrenches it is not neces- sary even to remove the screw. Each side of the bolt-head was cut differ- ently to give a certain amount of adjust- ment. Care must be used not to overtax the wrench when using the largest open- ings.—G. A. L.

103

nnn nn emee al Learn Drafting Employers everywhere are looking for skilled draftsmen. They are offering good salaries to start, with splendid chances for advancement. Drafting offers exceptional opportu- nities to a young man because drafting itself not only commands good pay, but it is the first step toward success in Mechanical or Structural Engineering or Architecture. And drafting is just the kind of work a boy likes todo. There is an easy, delightful way in which you can learn right at home in spare time. For 30 years the International Corre- spondence Schools have been giving boys just the training they need for success in Drafting and more than 300 other subjects. Thousands of boys have stepped into good positions through I. C. S. help. Never were opportunities so great as now. Let the I. C. S. help you, too. Choose the work you like best in the coupon, then mark and mail it. This doesn’t obligate you in the least, but it will bring you information that will start you on a successful career. This is your chance. Don’t let it slip by. Mark and mail this coupon now. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7662-B, Scranton, Penna. Without cost or obligation, please send me complete information about the subject which I have checked below:

OC DRAFTING [1 CARTOONING [] AUTOMOBILES [) CHEMISTRY [] ADVERTISING [] SALESMANSHIP () ELECTRICITY (1) ACCOUNTING CL) SURVEYING I ia c ci satisa tanciscuctaicureienac eimai cee Street PR cc cscitictiecixieievssinndipscbiaduinndbiaiinmae Ci ccssssasicssccssseasensasintasanse’ SOW sii kisicscactcstesetonanatis CRI ac ccccnesececnnenvemseonmnsnienanmeinntionniniainsiiian :

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104 Oil Experts Make Millions Oil, oil, more oil, is the crying need of indus- trial America today. And men, men, and more men are needed to supply the increasing demand. Such conditions make for big, handsome salar- ies for trained experts. It is not at all unusual for trained men to earn $100.00 a week, and in some instances $100.00 a day is paid to experts. o e,e New, Big Opportunities The opportunities in the oil industry for men of vision, daring and initiative are unlimited. You are the master of your destiny and income in this, America’s third vast industry. No powerful locomotive roars through the still- ness of the night without paying tribute to the oil industry, for its bearings float in oil. And even the needle on Milady’s sewing machine needs oil in the mechanism behind it for success- ful operation. It, too, pays tribute to you if you are in the oil business. And so on through in- ay Business houses large and small alike pay their share toward the industry. he year 1920 saw a production of 444 million barrels of oil. an increase of 67 million barrels over the preceeding year. Five thousand miles of new pipe line are built every year. Four thou- sand new wells are drilled every month. And each year sees 1,712 new oil companies with a capitalization of nearly three billion dollars. You can become an important factor in this tremendous industry. You can become an expert. All you need is a knowledge of how to read and write. We take care of every- thing else. There is a complete course of thirty-six lessons, easy and understandable. These simple lessons will prepare you to escape small pay and the drudgery of routine, and to step into the ranks of successful experts. Your spare time is all you need, plus your ambitious desire. Get Our FREE Book It telle all about this fascinating business for real men. Fally illustrated, packed full of facts that you should know. It means success for you. The course costs very little— the book costs absolu Y nathios. It is yours for the ask- ing. Get started now. Write for your FREE book today. PETROLEUM EXTENSION UNIVERSITY, Dept.604 165 HE. Ontario St., CHICAGO, ILL. » The New Dances Learned in One Evening by Arthur Murray’s New Easy Picture Method. 7 Let the Vanderbilts’ instructor teac! ou to be a good dancer. Learn the Tatest steps by Arthur Murray’s re- markable new picture method; surpris- ingly easy an fascinating—you need no music or partner. 60,000 taught dancing by mail.’” You, too, can learn at home, privately, in a few hours. FREE DANCING LESSON (oot ee ne Teen mecomalned ‘ee prove I can ma ickly! HALF PRICE OF' ON fowl or mailing , send 10c today! Arthur Murray, Studio 97, 290 B’way,N.Y. GENUINE DIAMONDS GUARANTEED When you buy aDiamond, you should deal withan old established house where you are sure you are getting your money’s worth, and whose reputationis unquestioned. Our 64 years of Service to the Public is our Guarantee of abso- lute satisfaction to }\l you and the safe- }} guard of your inter- CREDIT AT | Bo ay 5 A . The Ring is solid 18-k \) — White Gold, which looks like plate g&S i ? num: or solid Green_ Gold: a ee value reduced to $50 * USE ani q Write for Fi Wonderful Sond for Catalog. Seen cities Tan. Diamonds, Watches. Jewelry. Liberty Bonds Accepts d at P re Accepted THE NATIONAL JEWELERS Dept. L-871 108 N. State St. CHICAGO, ILLINOIS BROS&CO.fi53 4s STORES IN LEADING CiTiES | THE HOME WORKSHOP | Pattern of One-Piece Speedster | Body Design i ker construction of a speedster body should be of utmost simplicity, other- wise the work involved exceeds the ability of the average builder with his limited tool equipment. For the builder who desires to obtain the utmost in appearance with the least work, the one-piece design illus- trated in the picture is the best to select. The cowl, rear deck, and side body are cut from sheet metal about 8 ft. long and 61% ft. wide. This is wide for thin material f LJ 1 I HOOD iF —_— IN TWO PIECES . K~ a BACK SEAM THROUG COWL APP. 6 FT and it may be desired to seam two sections , Popular Science Monthly | OO) (0168 3 oF | Your Weaknesses Resist the elements of weakness and ill-health that are dragging you i down and sapping your very life i forces. Get rid of the nagging com- % plaints that make your life a wretched failure. Shake off Catarrh, Constipation, Indigestion, Dyspep- sia, Biliousness, Headache, Nervous- ness, Rheumatism, Asthma, Weak Lungs, Weak Heart, Rupture, Bad Habits, Lost Power and the numer- ous other results of neglect and abuse. Don’t put it off until you are down and out. Get busy NOW. STRONGFORTISM—The Modern Science of Health Pro- motion will show you how to Banish Your Ailments, Conquer Your Weaknesses and fit yourself for the Joys of Life. I guaran- tee it. Mention the ailments on which you want special confidential in- formation and send with 10c for postage, etc., on my book—‘‘Pro.- motion and Conservation of Health, Strength and Mental Energy.’’ It will point your way to — oon See. eae te my ree boo t Now— sf STRONGFORT . The LIONEL STRONGFORT Phystcal and Healih Spectalist Pactnen Gipm, Dept. 773 Newark, New Jersey A LUXURIOUS SEDAN The Wonderful ALL- YEAR CAR — Electric STARTER and LIGHTS — Drive Your Own Car ve l4recentlywonAuto Autos. y not you? Send answer today. { Ford Willison, Mgr, 141 W. Ohio St, Dept. 2570, Chicago, Ill. j This pattern has long, sweeping bends through the center before drafting and cut- ting out the form. This design will allow of a streamline body and the hood edge can be made as required to conform to the hood or engine cover installed on the car. No opening to the rear compartment is provided from the rear, but access is permitted by making the seat backs in one piece and removing these. The edges of the metal can be joined by either an angular section soldered to the inside edge or riveted along the edges. The illustration shows only the general form for any car and it is necessary to work out the proportions to fit the chassis frame and hood. The main consideration in this pattern is that no difficult bends are required, and where the metal is bent, the lofg sweep- ing bend is used. The average home-con- structed job irvolves short and difficult bends. These invariably show defective workmanship.-—G. A. LUERS. AN old inner tube is to the motorist what bailing wire is to the farmer. He uses pieces of it to protect his distributor cap, ignition wires, and battery from dirt and dampness. A strip takes the place of a carburetor choke spring in an emergency. On some cars pieces will do for temporary hose connections, fan belts, and gaskets. Tacked around pedal slots the rubber will prevent drafts, and cemented to the pedals themselves it may at some time prevent a bad accident. Rattles may be diminished temporarily by wedging in wads of rubber.—P. R. J. $150 to $300 MONTHLY PROFIT Charging Batteries- Start NOW! Get in this big money-making business NOW! Smali cash payment brings you any HB Battery er. , easy terms on balance. No repairs or renewals—no experience needed to operate. Sizes for char; 6, 10, 16 or 32 batteries at once. Let us recommend size to make yn biggest profits. Money back guarantee. Write also for information on HB Air Compressors, Tire Buffers, Ball Bearing Motors,—all big money-makers for your shop. HOBART BROS. CO., Box P3, Troy, Ohio. $20 Brings an HB Battery Charger M4 Eels, Turties, Mink, Muskrats ! a Cc and other fur-bearing animals 9 in large numbers, with our new Folding, Galvanized Steel Wire Trap. It catches them like a fly-trap catches flies, Made in all sizes. Strong and durable. Write for Descriptive Price List, and our Free Booklet on best bait known for attracting all kinds of fish. J.F.GREGORY, Dept. 26 LEBANON, MO. FLEXO WEATHER STRIPPING Superior to wooden and metal weather stripping. be applied by any one whocan use a hammer and tacks, Saves Fuel and Doctor bills. Increases Comfort. Keeps the heat in—Keeps the cold out. Flexible—Durable—Waterproof. Makes your house a home. Send for FREE SAMPLE, descriptive literature and prices. STUART PLASTER-PAD CO., 104 Stuart Bidg., St. Louis, Mo. 25 Miles Per Hour! is record of our stock car, using our special 1922 motor. Angbody can assem- ble this car. ba Send 30 3 Cents for plans, in. structions and price list of parts, SYPHER MFG. CO., 174 Sypher Bidg., Toledo, Ohie One-Half the Average Motorcycle Price Six other ‘‘big’’ motorcycles aver- age $370 in price. Yet the Cleve- land, with leadership quality un- questioned, sells at $185. Light weight—low saddle—safe. 75 miies to the gallon — 15,000 miles on_ tires. Write for Z “Ss Can 7th Year ; — March, 19 Takin wit I REC] | 2 graph /and fow gave an of the pl | Inord | plate W | spectacl which Vv trait ler

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March, 1922 THE HOME WORKSHOP Taking ‘‘Close-Ups’”’ of Objects with an Ordinary Camera RECENTLY had occasion to photo- graph a 10-in. statue on a 4 by 5 in. plate 'and found that my portrait attachment _ gave an image occupying only about a fifth of the plate’s surface. In order to obtain as large an image as the | plate would hold, I secured an ordinary spectacle lens, the magnifying power of which was half again as great as my por- trait lens. This was attached in place of | pad. | clamped between. | easily be trimmed off to the same size as the | block. Oil is applied to the felt through an CAMERA LENS How extra lens is attached to camera the portrait lens by means of a strip of card- | board in which two slits were cut. This strip was sufficiently long to encircle the regular camera-lens mounting and to lap for gluing. To those who like to keep photographic notes and references of small subjects such as plants, coins, and the like, this idea should prove useful as well as economical.—HAROLD M. STOWELL. A Self-Oiling Bit-Rack T° make this auger bit-rack, select a piece of soft “‘two by four’ and bore into it a series of holes at an angle. Each of these should be a trifle larger than the bit it is to contain. A piece of felt is then cut somewhat smaller than the block to serve as an o'l To prevent any surplus oil from RUBBER BELTING ALL AROUND, EXCEPT AT TOP. FOR MRIARUING THE OIL en ee ee D AUGER RACK HOLES OILED FELT “~WOOD BLOCIK SCREW SCREWED TO BASE. FROM THE BACK fpocos=ce- wm we wm wm ww ow we we ew ow we ww we ww ww oe wo ww wees —— RUBBER BELTING A cross section of the bit-rack | escaping, a piece of belting is cut out so that the felt will fit into it, as in a frame. Fasten the thin backing piece to the block with brads, the felt and belting being The belting can then opening in the belting at the top, slowly filtering through.—LovuIs SCHNEIDER. t Dividers Firm Join FIRM JOINT DIVIDERS No. 139 A new line of high grade Starrett dividers selling at a moderate price. These dividers are fitted with an improved firm joint and will be found very rigid. The points are hardened and the dividers are well finished throughout. Described and illustrated on page 277 of the new Starrett Catalog No. 22 “W.” Copy of this catalog sent free on request, also special Supple- ment showing new Starrett Tools. THE L. S. STARRETT COMPANY The World’s Greatest Toolmakers Manufacturers of Hack Saws Unexcelled ATHOL, MASS. 42-245 Only $45.00 For This Job Complete bitant fi t Save exor! gt folate Not Paper Patterns ny on All Parts Complete assemble this job. “Complete with hood, roar shell, instrument uphol. metal parts, wood p bolt screws, etc. Flat Tadiator shell Faroished f made u nbokonts low with lack of wind resistance. Price set up $90, urther particulars on request. The Central Auto Supply Co. Eng. Dept. 122 Louisville, Ky. Tool wise machinists, car- How penters, plumbers, garage mechanics, _ electricians, and others keep them in Union Tool Chests. Fur- to nished in every style or size needed. Any price you can afford. Keep Write for free descrip- tive booklet. Tools Union Tool Chest Co. 36 Mill St.. Rochester, N. Y. EXPERIMENTAL WIRELESS STATIONS By P. E. EDELMAN. The theory design. construction and operation is fully treated, including Wireless Telephony, Vacuum Tube, and quenched spark systems. 24 chapters, 167 illus. Price, $3.00 POPULAR SCIENCE MONTHLY, 225 West 39th St., New York Handles 4’ ones saws; 6°’ motor. Extremely compac highly aie aed decidedly Divettca Not a to %;, el Wei 31 Ibs. Easily jh en with 1-4 motor. Suited x S78. Inst. Lae Furn Ship ping Depts. Schools, Laboratories, Private Shops, ete. achine fully guarante i di heel: a RY he 38"’ | chuck. “— easily hase with inters. Cait: net and woody ‘Makers, Musical Repairmen, Manual Training W. & J. BOICE, 112 23d St., Toledo, Ohio HOW TO PAINT Our book gives a complete course of —. & abling any one to learn to paint geod signs. NOT MAKE YOUR OWN either for your wa, e for others? Contents: Alphabets, Composition, Color Combina- tions, How to Mix Paints, Show Cards, Window Signs, Banners, Board and Wall Signs, Ready Made Letters, Gilding, Commercial Art and Tricks of the Trade— Contains 100 alphabets and designs. Cloth bound, size 7 x 5 inches, Price $1.00 postpaid. J. S. Ogilvie Pub. Co., 206 Rose St., Rew York SOUTH 9” x3’ Lathe 11” x4’ Lathe 13” x5’ Lathe 15” x6’ Lathe Run a Lathe An 80-page book for 10c. Postpaid, Coin or Stamps. tandar: Change Gear Change Gear REDUCED PRICES BEND LATHES—EST. 1906 Quick — oleae - Change Gear $176.00 $216.00] 16’x 8’ Lathe $452.00 $512.00 228.00 273.00] 18”x10’ Lathe 656.00 721.00 304.00 354.00 | 21”x12’ Lathe 848.00 923.00 376.00 431.00 | 24”x14’ Lathe 1140.00 1230.00 Free Catalog No. 67 SOUTH BEND LATHE WORKS, 433 E. Madison St., SOUTH BEND, IND.

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“‘Red Devil’’ Pliers made in 100 styles—one for every need. Known and used the world over. Style No. 1024—6% inch shown here. From dealers or from us, $1.00. \ied Dewil/ Reg. U. S. Pat. Off. Tungsten Steel Hack Saw Blades For Hardest Cutting , A) ts hl in Chiwetel 1 cH = H Ley 2 & 4 ED DEVIL” dependable hack saw blades of tungsten steel have been giving satisfaction for years. They do 30% more work than others and last longer. Every blade indi- vidually tempered. This means extra money and time— but gives a blade that cuts practi- cally anything without breaking or teeth stripping. Guaranteed abso- lutely. Teeth are milled, not punched, with sharp, square points that cut metal as easily and rapidly as a rip-saw cuts wood. Try them to your own satis- faction and you'll always use them. Obtainable from your dealers, or if not in stock, send 75c for one dozen “Red Devil’ Hack Saw Blades No. 1239—10-inch. “Red Devil” Hack Saw Frames are just as reliable—ask your dealer. The ‘‘Red Devil” Mechanic's Tool Booklet is yours for the asking. SMITH & HEMENWAY C0., Inc. Manufacturers of ‘‘Red Devil’’ Tools 264 Broadway New York,N. Y. "Red Devil’’ Glass Cutters—the glaziers’ standard tools of the world. “It's all in the wheel.” Made in 40 styles. No. 024 shown below, 20c.

T HE HO ME ‘ORK “SHOP

| <a for Spring Gardening by Making This Wheel-Hoe ccs backbreaking labor in the garden can be saved with a wheel-hoe or cultivator such as is illustrated. It was made of % by 3 in. strips of wood bolted together, with an old wheel and a blade that was made by a black- smith at small cost. The handles are 57 in. long, the horizontal members 2214 Z in., the verti- The wheel-hoe cal members 18 in., and the cross pieces 814 in. The blade is screwed to the vertical members. Pieces of bicycle tires make good grips for the handles. This wheel-hoe has been used for two years and is today as good as it was when made.—JOHN NEUERBURG.

Saving Gas in the Kitchen HIS gas-saving device may be made to cover two or four burners of a gas- plate or -range. If the sheet metal available GAS*SAVER IN USE

Po Si H H To} i oa ; a 4 a ' inact —G BLACK LINES SHOW WHERE TO Cut * FINISHED DOTTED LINES WHERE TO FOLD CORNER

REENFORCEMENT A INSIDE PAN SHOULD NOT BE HIGHER THAN DEPTH OF PAN. Making two burners serve as four

is not heavy enough to support the weight of the cooking utensils without sagging, a reenforcement should be provided asshown, riveted to the center of the pan. The draw- ings are self explanatory.—L. C. How to Make Wire Cable Eyes O put an eye in an end of a cable by splicing is an art that takes practice and patience. The illustration shows a prac- tical substitute. A pipe tee and pipe plug of suita- ble size are used as a coupling and binder. The loop of the able is caught in the tee and the plug is screwed down as tightly as possible. An ad- ditional seizing can be made of wire on the two parts in front of the tee.—R. N.

A pipe-tee binder

Popular Science Monthly BETTER GARDENS The sure way to have a more productive garden is to use as your guide— The Maule FREE Seed mnen Send a postal today for your copy of the won. derful 176 pa 1922 edition. “ MAULE’S SEEDS Once Grown Always Grown Wm. Henry Maule, Inc, 2301 Arch St. Philadelphia

' “MAULE i SEED BOOK

for 1922 t

FREE CATALOG 2.05 2noucheen in cuss. Either pin illustrated made with any equal 4, amount of lettering, one or two colors enamel. Silver plate, 202 ea., $2.00 doz. Sterling silver, ea. ,84.00 doz. Write to-day for newcatalog. | BASTIAN BROS, CO. R 391 Bastian Bidg.

Rochester, N.Y.

WRITE THE WORDS FOR A SONG We revise poems, write music and guarantee to secure publication by a New York Music Publisher. Our Lyric Editor and Chief Com- poser is a song writer of national reputation and has written many big song-hits. Submit poems on any subject. We examine them free, BROADWAY STUDIOS 249 Fitzgerald Building Broadway at Times Square New York, N. Y.

R 5 Keen, Clas ssy Up to the minute é&

ow keys EREnOGA their kind in existence—(patent- Open and test thousands of different vad lly Tell you instantly it your door or padlocks are burglar proof. Serve in emer- gencies, too. Thousands of setsin daily use among detectives, policemen, contractors, locksmiths, firemen, mechanics, travellers, home and hotel owners, etc. Give feeling of security and rotection worth many times their eost. Novel key chain FREE. Send $i today. Master Key Co., 6S Manhattan Block, Milwaukee, Wis.

often a en Beye their boys smell par TO RIDER Three big model factories balan ori rices. \ d WN DELIVERED FREE, smonaeeaneer Por express prepa: 30 DAYS TRIAL, Sel ‘terms dhatculcast ; Fens ect bicycle and if ires lamps, horsa,whee is, parts and fa preven Noe MONEY rp = a, write a, today for big jog and and terms. : Mead < Cycle Company a \( Dept. T1099 Chicagonrider Agents “DON’T SHOUT” © “T hear you. Ican hear now as wellasanybody. ‘How?’ With THE MORLEY PHONE. I'’vea pair in my ears now, but they are invisible. I would not know ‘ I had themin, myself, only that I hea: all right.” The Morley Phone for the DEAF is to the ears whet glasses are to the e

we Anyone can adjust it. sted bg Sauer a Write for pookice and test! — THE MORLEY CO., Dept. 797, 26 | oo 15th Street, Philadelphia

Mw Mi: ca Se 8 a F B A ™ 9 v eaaneD pee BN -— tmaee ea eee eee th oe

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WHITING-ADAMS BRUSHES For Household and Family re- quirements. Best quality, long wearing, perfect working. Ex- tensive assortment,—every brush needed for home life. Send for Illustrated Literature JOHN L. WHITING-J. J. ADAMS CO. BOSTON, U.S.A. Brush Manufacturers for Over 112 Years and the Largest in the World 10c CHARGES Storage Battery At Home With an FBR F-F BATTERY Y BOOSTER, which Ac. Cc. Baap pene oun or f. bai oe inals. be Chai Nos mkII, required. wi: A Complete Compact Pornbio Charging Unit; Do not think your etary is dead simply because it will not start your Booster and Fill it with Life. Money. ‘Tastea Li tam ion Type charges bo’ t batteries at 12 &7 = ents ~. Large are for hea “Batteries 3, or where _ limited. Ship ins ¥' os! iz Complete wi ~ & Battery Sen check Des Nee RE ERLE ROTARY THE. FRANCE MFG. ig On CLEVELAND, ee be U. xi A. Cc. » Hamilton, tery Service & Sales Co. ? re anes nd Gord Tinge. oe staan reas 8,000 & £10,000 Miles (No Seconds). Hand made. Finest t materiale, FREE” TIRES POR YOURCAR to locali one user ineach s FR first to write quick for 5 a Agents Offer and Low Wholesale Prices. MELLINGER TIRE & RUBBER CO. 962 North Oak St. Kansas City, Mo. Help Wanted We require the services of an ambitious person to do esome special advertising work right in your own locality. The work is pleasant and dignified. Pay is exceptionally large. No previous experience is required, as all that is necessary is a willingness on your part to carry out our instructions. If you are at present employed, we can use your spare time in a way that will not interfere with your present employment—yet pay you well for your time. If you are making less than $150 a month, the offer I am going to make will appeal to you. Your spare time will pay you well—your full time will bring you in a handsome income. It costs nothing to investigate. Write me to-day and I will send you full | aoc lhapaoage te by return mail and place before you the facts so that you can decide for yourself. ALBERT MILLS, __ Gen. Manager Employment Dept. 6552 American Bldg., CINCINNATI, OHIO THE HOME WORKSHOP ta sewing-machines, junk dealers, will make a useful small com- iil sp BUSINESS Make Real Money on Small Capital All over the U. S. and Canada we are establish- ing Vulcanizing Service Stations. Start one in yourtown. Make $10 to 0 per day_on a $350 investment. We instruct you and_ furnish the Most Modern Methods and Equipment— THE ANDERSON Known the World Over We have 34 Schools in U.S. and 4 in Canada. One is ater you, School pays has $5 per day while learning rate your station. Write for full particulars- TODAY. yue ANDERSON STEAM VULCANIZER CO. Manufacturers of Modern Tire air Equipment, Building a Foot-Power Machine for Light Work which usually | may be obtained at small cost from bination footpower machine for the home workshop or for a repair-shop. Ata cost of | less than $5, the writer has just completed one that is a miniature machine-shop in itseli—a hacksaw, jigsaw, emery- -grinder, polishing-wheel, drill-chuck, and vise. Obtain one sewing-machine frame with foot pedal and driving-wheel complete and three or more old machine heads. Mount a heavy plank top on the frame and fit up the machines as shown in the illustration. The first will operate a hacksaw or fret- saw blade, clamped to the needle-shaft POLISHING EMERY~ DRILL VISE FEEDS WHEEL \\ WHEEL CHUCK WORK TO 4 S DRILL HACK SAW A machine-shop in miniature after the presser-foot has been removed. The blade passes through a slot in the table and is attached to a spring underneath. The second head is sawn off near the pedestal, as shown, the shaft shortened and a bearing made of Babbitt-metal. The wheel is wood, covered with fine emery- cloth. The third head is mounted in the same way and drives an emery-wheel. Into the other end of the spindle a drill-chuck is screwed. The work is held against the drill vise. able jaw will serve to press the work against height; and the vise itself will still serve for light work, or even for heavy work, if sub- stantial bench legs are placed beneath it. In remodeling the frame below, a hanger was provided for the long drive-shaft and driving crank is outside.—R. E. LEIBE. Thumbtack Pads for Draftsmen | © eennn of blotting-paper with the centers How the pads are used in such a way that the heads of the tacks will not project above the surface.—K.H.H. 101 Williams Bidg., ndianapolis, U. S. A and fed to it by means of an ordinary bench | The end of the slide bar of the mov- | the drill if the vise is mounted at the right | the crank wheel turned around so that the | rem ved may be placed under the | drawing-paper beneath the thumbtacks | You Go on from the High Mark Performance counts—when you ve a Veeder Counter on your machine! Counts so you can watch it and develop it. The record of a Veeder Coun- ter may show satisfactory efficiency in a machine, or it may show merely a good beginning in mechanical de- velopment. Usually the high-point in a machine’s_ production _ be- comes the starting-point for new records, when you put on a COUNTER The Set-Back Rotary Ratchet Counter below is for machines such as punch presses and metal-stamping ma- chines, where a reciprocating movement indicates an operation. Registers one. for each throw of the lever, and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure- wheels, as required. Price with four figures, as illustrated, $11.50—subject to discount. (Cut less than 14 size.) Set-Back Revolution Counter of similar model, $10.00 (list). Speed Counter Here’s the handiest instrument for finding revolutions-per-minute of a shaft or flywheel. You hold the tip of the counter against end of revolving shaft; press lightly when the second hand of your watch comes to O; release pressure when minute is up. %y eet (Cut less than 1% size.) The Veeder Speed Counter enables you to keep motors, engines, generators, line shafting and machines operating at efficient speeds. Price, with two rubber tips (as illustrated) $3.50. Send for free booklet no mat- ter what you want to count— automatically or by hand. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn. eS re aaa nd oper ol tes 7 toa ees ER aR Sa ve She SOE es = w= Lane Nae WD ne SS eae te NEED T ITA ie ron ans t

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rrr 108

Mechanical Engineering |

EE Learn at Home! Employers are looking for men with mechanical ability. There is an easy, delightful way in which you can learn right at home in spare time. For 30 years the Interna- tional Correspondence Schools have been giving men and women just the training they need for success in me- chanical engineering and more than 300 other subjects. Hundreds of thousands 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 below, then mark and mail it today. This doesn’t obligate you in the least but it will bring you information that will start you on a successful career. This is your chance. Mark and mail the coupon now. —_— a TEAR OUT HERE == ——— =e oe INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7663-B SCRANTON, PA. _, Explain, without obligating me, how I can qualify for the position, or in the subject, before which I mark X. ELEOTRIOAL ENGINEER as ENGINEER

Electrician P rod L) Electric Wiring . SALESMANSHIP Electric Lighting ADVERTISING MAN Electric Car Running tel a. - Heavy Electric Traction ow and Sign Paint’ Electrical Draftsman RAILROADPOSITIONS ILLUSTRATOR Electric Machine Designer DESI polegrer’ Expert GNER Practical Telephony BUSINESS MANAGEMENT MEOHANICAL ENGINEER ee Mechanical Draftsman DOORRER Ene nent Ship Draftsman Ste mographer and Typist Cert. Pub. Accountant Traffic Management Commercial Law OD ENGLISH STATIONARY _ Toolmaker Gas Engineer CIVIL ENGINEER ; Machine Shop Practice Surveying and Mapping MINE FOREM'N ORENG’R CIVIL SERV ARCHITECT | Hiakcurrec Draftsman Railway Mail Clerk Text : PLUMBING AND HEATING ¥ AGRICULTURE

R Sheet Metal Worker Apereeicbe tg Spanish Navigator Automobiles Banking Name Present Occupation—_ Street and No,

Jot Business os Ada

City. State. Canadians may send this coupon to International Corre- Spondence Sohools Canadian, Limited, Montreal, Canada

Music Lessons bade same toto ait Wonderful home study musie i? At Home lessons under great American and European teachers. En- dorsed by Paderewski. Masterteachers guide and coach you. Lessons a marvel of yee and completeness. _ ritenaming course you are interested Any instrument in:Piano,Harmony, Voice,PublicSchool Music, Violin,Cornet, Mandolin, Guitar, Banjo or Reed Organ —and we will send FREE CATALOG. SEND for it NOW! UniversityExtension Conservatory 525 Siegel-Myers Bldg., Chicago MANE MUNEY AT HUME OU can earn from $1 to $2 an hour ip your spare time writing show cards. Quickly and easily learned by our new simple method. No canvassing or soliciting. We teach you how and guarantee you steady work at home and pay you cash each week. Full particulars and booklet free.

AMERICAN SHOW CARD SCHOOL 206 Ryrie Building Toronto, Canada

——————— = ee = SOLDERING- IRON J

~ -> The holder is formed of twisted wire stiff wire about 2 ft. long. It has two loop ends and is doubled into supporting arms to serve as a rest for the shank of the bit. The device may quickly be placed over the gas-jet when required and as quickly re- moved.—G. L.

To Stop Casements from Rattling ~~ I purchased my home, the second-floor windows, which are of the casement type, rattled to an annoying extent. To prevent this, springs, washers

Applying the springs

SPRING

and pins were used on the sash adjusting rod in the manner illustrated so that all play between the parts was taken up and the windows could not rattle. Simply drill the holes for the pins, re- move the rivet from one end of the rod, assemble the parts, and re-rivet.—H. N. W.

Split Nut Holds Bolt in Vise HEN it is necessary to hold a nut in the vise while slotting it, drilling a cotter or wire hole through it, or cutting down its length, a simple method to avoid mutilating the threads while clamping it —

Zz NUT IN VISE DETAIL OF NUT The nut protects the threads securely is to screw a partially split nut over the thread. It can then be clamped in the vise as solidly as desired without any damage being done to the threads. Studs, shafts, or other threaded parts can also be held by this means.—A. L. G.

Popular Science Monthly THE HOME wctncmnd nl “i hy e rl 39 Holder for Heating Soldering-Bit g ting ixtures over Gas-Jet . Ready to hang, ete the occasional user of a soldering-bit, Direct from man- this holder is both simple and service- fact _ able. The tip is held in the hottest part of ulacturers. : | the flame of a gas-jet by a twisted piece of Completely wired including glass- ware. Send for Catalogue No. 20 ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa. FOR ALL PURPOSES NEW MOTORS STANDARD MANUFAGTURERS PROMPT DELIVERY ALL SIZES UP TO 5SH.P. We Specialize In Small Motors & Generators ALL PHASES AND FREQUENCIES IN STOCK AT ALL TIMES Largest exclusive Mai! Order Small Motordealers in the world. CHAS. H. JOHNSTON, ye 14K Co End, Pittsburgh,Pa.

WIRELESS, TELEPHONE GENERATORS 500 VOLT- 100 WATT - 3400 R.P. M. FOR gunn MOTOR GENERATOR SETS.

BUCHSTEIN’S FIBRE LIMB soothing to your stump— strong, cool, neat, light. Easy payments.

fy Braces

for all Guaranteed 5 Years deformi- Send for Catalog Today. ties.

P-BUCHSTE!N CO., 113 6th St., S. MINNEAPOLIS, MINN. LIEN TY. 4 4 By Note or Ear. With or without music. Short Course, Adult beginners taught by mail. No teacher required. Self-Instruction Couise for Advanced Pianists. Learn 67 styles of Bass, 180 Syncopated Effects, Blue Harmony, Oriental, Chime, Movie and Cafe Jazz, Trick Endings, Clever Breaks, Space Fillers, Sax Slur, Triple Bass, Wicked Harmony, Blue Obligato, ‘and 247 other Subjects, including Ear Playing. 120 pages of REAL Jazz. 25,000 words. A postal brings our FREE Special Offer. WATERMAN PIANO SCHOOL 260 Superba Theatre Building Los Angeles, California How to Get Rid of Moles A simple, safe home treatment— 15 years’ success in my practice. Moles (Also BIG Growths) Dry Up. Ask for Free Booklet of Full Particulars WM. DAVIS, M.D. f 124-6 Grove Ave., Woodbridge, N. J.

Cut out this ad and Mail it to us, with your name and address (no money); and we will send you our FAMOUS KARNAK RAZOR by return mail, postpaid. You may use the razor for 30 days FREE ; then, if you like it, pay us $1.85. If you don’t like it return it. SEND NO MONEY. MORE COMPANY Dept. 397 St. Louis, Mo. Don’t Wear a Truss Brooks’ Appliance, the modern scientific invention, the wonderful new discovery that, relieves rupture, will be sent on trial. NO obnoxious springs or pads. MR. C. E. BROOKS Brooks’ Rupture Appliance Has automatic Air Cushions. Binds and draws the broken Taye together as you would a broken limb. No salves. No lies. Durable, cheap, Sent on trial to prove it. Protected by U. il gg Catalog and measure blanks mailed free. Send name and address today. Brooks Appliance Co., 255D State. St., Marshall, Mich.

6 plains refinis! floors }

If so, ¥ and us woods wood. apply. capaci Our | proms w We wi the n< we W Johns

|

Page 93

March, 1922 a

This Book On Home Beautifying Sent Free Contains practical sug- gestions on how to make your home artistic, cheery and inviting—ex- plains how you can easily and_ economically refinish and keep woodwork, furniture and floors in perfect condition. o & -~ Building?? If so, you will find this book particularly interesting and useful, for it tells how to finish inexpensive soft woods so they are as beautiful and artistic as hard wood. Tells just what materials to use—how to apply them—includes color card—gives covering capacities, etc. Our Individual Advice Department will give a prompt and expert answer to all questions on interior wood finishing—without cost or obligation. We will gladly send this book free and postpaid for the name of your best dealer in i. And for 10c we will also send you postpaid a 2 oz. bottle of Johnson's Liquid Prepared Wax. S. C. JOHNSON & SON, Dept. PS3, Racine, Wis “‘The Wood Finishing Authorities’’

eae ceniencimanientimeniaiameieieiiesiamminiael ASBESTOS We are miners and shippers of Crude Asbestos in any quantity. We produce all grades at our world famous BELL ASBESTOS MINES, in Canada. We also card fibres, spin yarns, weave cloths, and make all sorts of Asbestos products. For anything you want in Asbestos turn to

Keasbey & Mattison Company Dept. S-4, AMBLER, PENNA., U.S. A. Owners of the World’s Largest Asbestos Mines

The gst “*Five-in-One”’ Slide Rule ination Mannheim, Polymet- \ 8S ie eanery, Add and’ Bok tract Slide le. It will instantly add, \\ subtract, multiply and divide any com- bination of whole ampere. tions, | mixed numbers and decimals. Gives J overs root end wer, ye Loes.-Sines angents. je 0! luminum * scales on white celluloid. Size 4 in. Approved and adopted by colleges. Brice wi nstructions, $1.50. Leatherette Case 50c. extra. Cata- logue Free, Gilson Slide Rule Co., Niles, Mich. COLD PIPE BENDERS Standard of the World

14 sizes of machines What it costs to bend pipe our way Models E & F per ben jin. Pipe. & eents $2. Pine. 4 conte in. . - Pipe, en devt8 in. Pipe, $1.00. American Pipe Bending Machine Co. Send for catalogue 51 Pearl St. Boston, Mass. Mt We J S|] | (tA | | pay Se SIGNS Ki AX) \e *

)— +N . -— Z Ne TH 60—$200 a week. Free Oo @OLD SIGN LETTERS for store fronts and office windows. Anyone can put them on. No experience necessary. Big demand. LIBERAL OFFER TO GENERAL AGENTS. METALLIC LETTER CO., 433A N. CLARK ST., CHICAGO

THE HOME WORKSHOP

A Useful Gage for Cutting Short Lengths of Wire QOMETIMES a number of short lengths of wire are required for certain work where only pieces of uniform length can be used. It is not easy to make accurate measurements be- cause the cutting <Z edges of the pliers are beveled. To overcome this dif- ficulty, provide a simple gage such as is shown here. ) It s made of any S*& heavy sheet metal and the double end is bent so that the strip will hold firmly on the pliers.—D. C,

Gage for pliers

Winding Springs on a Screw Te make springs with evenly spaced turns will be easy if the wire is wound LATHE-CHUCK a= (CACC SPRING WIRE Turns are uniform on an old screw. The screw should be held and turned in a lathe-chuck.—J. B. MORAN.

Repairing Celluloid Articles | nage anything made of celluloid can be repaired, patched, built up, and otherwise worked with the aid of ordinary film cement such as is used in splicing motion-picture films. Where there are flat surfaces of sufficient area to give a good hold, the parts are simply cemented together after the surfaces are cleaned by scraping. If the break is in an angle, put a little film cement in a small bottle and drop into it cut scraps of celluloid film. Old — camera films are CELLULOID FILLET", good for the pur- pose if all the emulsion has been washed off with hot water. The mixture

STRIPSOF CELLULOID BREAK

echXPED DOWN AND POLISHED —_ should beofabout Mending breaks the consistency ofvery soft putty. First cement the parts together in the ordinary way, so that they will hold tem- porarily. Then, with the celluloid mixture work a fillet or filling into the angle to act as a reenforcement, putting the putty on over a coating of cement. Although this dries rather slowly, it gets hard and makes a good job. A flat piece -an often be mended by cementing a thin strip of celluloid on each side. The edges of the strips can be worked down by scraping when the cement has set, so that the surface will be smooth, and can then be polished.—HOWARD GREENE.

eF: A Clean Sharp Cut Every Time! HE cutting blades of Never- slip Pliers are made from high carbon crucible steel. That’s why they’ll outcut and outlast any plier made. Crucible makes a strong tough edge that resists wear and remains sharp for a long time. But should you ac- cidentally nick the crucible edge your won’t have to throw the pliers away. Neverslips are made with renewable cutting blades. You merely remove the nicked blades and insert new ones (just like a safety razor) and you have a brand new plier ready for use at the cost of only one pair of blades. Neverslip Pliers will cut soft wire or insulation clean and even—no rough or ragged edges. Your hardware dealer has them! THE NEVERSLIP WORKS New Brunswick, New Jersey

NEVERSLIP side cutting pliers Neverslip Pliers are furnished in six, seven and eight inch sizes If you use pliers or buy them for somebody else to use, you'll be interested in our book- let, “Procrastination is Not the Only Thief of Time”. It’s mailed free upon request. Do you want a copy?

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110 HE experienced mechanic knows the points of Cc superiority in Brown & Sharpe Machinists’ Tools that make a difference to his work. The correct and carefully fitted parts, the clear and clean cut graduations, the distinguishing finish, the world known accuracy, and long life are reasons why Brown & Sharpe Machinists’ Tools are the skilled craftsmen’s choice. Their use brings a constant and increasing appreci- ation. These superior tools are shown—over 2000 of them—in our Catalog No. 28. Send for it. BROWN & SHARPE MFG. Co. Providence, R. I., U. S. A. Popular Science Monthly You Can Save $50.00 By recovering your old auto top frame yourself. We make these recovers to fit 5 40 all makes and models of cars. 'e Any a oan poe car can put it on e furnis and wt x instructions, f an Parcels Post Paid ters sewed together with rear curtain, fasteners, welts and tacks. All complete. Give us the name, year and model number of your car and we will send you our catalogue with samples and quote you exact price. LIBERTY TOP & TIRE CO. Dept. E8, Cincinnati, O. Standard Underwoods! Greatest Typewriter BargainEver Offered Right now we want to make you the greatest typewriter offer you ever dreamed of. An eye-opener. Only $3 down and this newly — o_o nen tandard visible writ- ing Underwood will be DOWN shipped to you now— i at a very special price on easy monthly pay- ments or cash. 10 DAYS’ FREE TRIAL Let us ship you this machine direct from our big 4 factory. Try it for 10 days and use it in your work. If you or anyone else can get finer work or better service out of any other typewriter inthe world, regardless of price, don’tkeepit. Simply ship it back to us and get your money, together with any express charges you may have paid. Aa Direct from Headquarters By buying direct from us you save from 25% to 40% on new Columbia motors, and as high as 50% on Fuerst-Friedman rebuilt motors. You save retailer’s profit— you save retailer’s high sales cost—and you get motors fully guaranteed for one year. No matter what your motor requirements are, from tiny buffing motors to heavy-duty factory motors, we have a new or rebuilt motor to suit your exact needs. And the costis from 25% to 50% less than you would pay elsewhere. Send for our big free motor book—see for yourself the savings you get by buying from us. It tells all about our twenty years of successful motor service—all about At left is shown the largest typewriter rebuilding plant in the world. Estab- B lished 1892 — $25,000 4 satisfied customers, many vast engineering projects we have handled. Ask for Book No.90—the price regulator on new and rebuilt motors. Electrical Machinery of all kinds promptly repaired or taken in exchange. THE FUERST-FRIEDMAN CoO., CLEVELAND, OHIO. ** Reliability Built In’’ TYPEWRITER EMPORIUM SHIPMAN-WARD MFG. CO. 2143 Shipman Bldg. Chicago, Illinois COLUMBIA MOTORS ~ THE HOME WORKSHOP Ciamp with Setscrew and Nut Has Viselike Grip GHAFTING that is difficult to grip with an ordinary C clamp, may be held as in a vise by a clamp similar to the one illus- trated. The cross section shows the con- struction. The movable member does not have any turning or swiveling movement, but is CLAMP SQUARE HEAD Only the casehardened nut turns simply a cup-pointed setscrew capable of only longitudinal movement. Tightening the clamp is accomplished by turning a casehardened nut. A square hole nearly through the clamp body holds the square head so the screw never turns.—D. A. H. A Novel Self-Locking Dovetail f ipeaee home worker who enjoys experi- menting with the more elaborate cabinetmaking joints will find much to interest him in this new joint, devised by a Frenchman. It is a dovetail tenon such as frequently is used in good furniture con- struction for top rails in order to prevent end-frames or members from spreading. [ZZ DOVETAILED WOINT Ui Yi) Uy D D : A new LOCKING SCREW dovetail Made in the manner illustrated, the joint can easily be assembled or disassembled through the use of the small locking-piece. The obvious objection to it is that the thickness of the saw-kerf would be sufficient to spoil the accuracy of the joint, but that difficulty can be avoided if the curved cut is made before the dovetail and mortise are shaped. The hole for the screw should, of course, be drilled first of all and the locking- piece screwed temporarily in place before the dovetail is cut.—Louis DouGLAs. Preventing Lost Motion in Vise sarap using a vise at close range, any lost motion in the screw is’ objection- able. In order to prevent an- noyance from this cause, an automobile valve-spring may be attached to the movable jaw by means of an angle-iron sothat it presses against the stationary BOTTOM OF | VISE J VOLE DRILLED TO RECEIVE AUTO VALVE-SPRING : by of standa dimen blocks collim accor frame enam Th lense: oh i ae “alii jaw.—H. B. The spring attached |

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th iS- n- ly is Mareh, 1922 hn =, 111 THE HOME WORKSHOP Making a Spectroscope for the Home Laboratory : ie first step toward the construction of this spectroscope was having the standard members turned to the indicated dimensions. I then made up the two blocks H, which support the telescope and collimator tubes. Their size will vary according to the lenses used. After this framework was assembled, a coat of black | enamel gave the whole a fine appearance. The telescope was constructed from two lenses, A and B, taken from a pair of old Top view, front view, and details field-glasses, and two cardboard tubes, F and G. The detail sketch T shows the manner in which the lenses were mounted. The collimator consists of a lens, X, of about 10-in. focus in a cardboard tube D, 8 in. long, another tube, E, 6 in. long, anda very thin brass disk N, with a slit in its center. This slit was made with the fine point of a knife. The method of mounting the lens and disk is the same as shown at T. I purchased the prism that was mounted on K by a spring brass bracket C. The housing O, is a cardboard box that slips over the prism. The inside of the tubes D, E, F, and G, and the box O, were painted a dull black.—W. J. EDMONDS, JR. Auto Spring-Leaf as Pickax A PICKAX for breaking up soft soil can be made from one leaf of a discarded automobile spring. Remove the leaf that appears to be the stiffest, and grind down each end to a point on an emery-wheel. Then drill two holes in the cen- ter. Bolt the leaf to the end of a stout handle with long, thin lag- screws. The head end of the handle must be reenforced with a ferrule so that the screws will not split it.—L. R. POINTED LONG WOODEN HANDLE - ~IRON FERRULE LAG- SCREWS LEAF OF AUTO SPRING For light garden work Great Motor Think of it? A big-capacity Bargain ly h.p., alternating gt ~ current motor, tested at Pig the factory for 50% overload, and _ fully guaranteed for one year § for— $1350 — ' furnished You'd pay nearly double from a any other source. Post ‘ Motor is for 110 volt—60 cycle service, Terminal 1740 rpm, split phase, fan-cooled, induction type; with cord and plug as shown; or, re- versible style with binding post terminal. Weight 24 Ibs. bare or 33 Ibs. boxed. ; ; - On 3 motors ordered in 1 shipment, price is $13.00 each; six Quantity Discounts: motors, $12.50 each; 12 motors $12.25; 25 motors $12.00 each. Send Cash With Order or we will ship by express C. O. D., if you prefer NORTHWESTERN ELECTRIC COMPANY 410-420 SO. HOYNE AVENUE, CHICAGO Cord | | HOW TO conbUCT A RADIO CLUB Buscher Covers parliamentary procedure, indoor and outdoor ex- to $26 on the model = periments, 5,000 mile receiving sets,’ vacuum tube amplifiers : colo! id detectors and th bjects. i ee AES pp. Fully illustrated. Price 7Sc het fakers tor 56 pays tree Trial ~_ POPULAR SCIENCE MONTHLY >MonthstoPay aoa pee 225 West 39th Street New York City 12 once on our Ub- MONARCH Do girl can save the email monthly payments. ives ws, chains, parts and equipment at half usual prices. RANGER CATALOG FREE, with mar- Bre RACER Oat cial offer end terme. velous pri Mead 67:12 company: JUNIOR LATHES “The Biggest Little Lathe Built” A sturdy cage engine Lathe built with the same quality construction that has mad MONARCH ENGINE LATHES ps ie the world over. An accurate, dependable machine tool especial- ly designed for and guaranteed to do any small work that any other lathe will do with speed and accuracy. MONARCH JUNIOR will fit in any shop or ina work-room right in yourown home. They are especially designed for beginners—are easy to learn to operate and are equipped the same as any larger lathe. The Greatest Achievement in Lathe Building History Monarch Junior 9 in. Engine Lathe $225.00 With Bench Legs Full particulars and a Monarch Junior Cata- log will be sent you on request. THE MONARCH MACHINE TOOL CO. 201 Oak Street - - Sidney, O. yours. c on convenient payments. in great variety. Larkin Book for Better Hores. [_] Furnishings [ ] Symphonic Pianos [_ ] Symphonolas (Check offer interested in) ing above. NO Money Down — 30 Days FREE Trial— 1 to 4 Years TIME Check offer now. name and address. Mail TODAY. Leavkitt Co tac. Desk—FPSM-322 Louis XVI Buffet And this beautiful Period-model Walnut Buffet is Complete Dining-rooom Suite to match. All Living-room Bedroom Suites Complete Furnishings for the home await your selection from our big 128 Page FREE { | Symphonic Player Pianos Symphonic Pianos, Symphonic Player Pianos and Symphonolas (the phonograph with natural tone, which plays all records) sold to tens of thousands of music lovers the past nine years. Get our Book describing these famous musical instruments by check- Cut out this ad. Give your full Buffalo. N. Y.

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112 Carpenter’s Rule Serves as Square and Protractor CARPENTER’S ordinary 2-ft. rule can be made to serve as a square and bevel with sufficient accuracy for ordinary work by scribing a series of marks on the brass-rule joint. ‘Use a steel square or a ; B fi ‘ea at Laying out angles with a 2-ft. rule draftsman’s T-square and triangles to set the legs of the rule exactly at right angles to each other, and at 60, 45, and 30 degrees, and in each position draw marks as shown in the accompanying illustration. I marked off a rule in this manner and have used it to advantage many times in my work.—JOHN DONOVAN. Easy Method of Simplifying a No. 1 Morse Taper He’ often have you required a taper- pin to fit either the headstock or tailstock spindle of your lathe? Possibly you have needed it to make a drill- pad or a friction chuck to hold some small part accurately. A taper-pin properly fitting your lathe is one of the most difficult things to make along orthodox lines. The accompanying sketch illustrates how the difficulty may be overcome. Set your slide-rest on the required angle and machine the stock nearly to size, then recess it as shown, and finish to a perfect fit with file and fine emery-cloth. You will find that it will hold as well if not better than a taper-pin proper.— WILLIAM J. BEACH. RECESS g \A LA MORSE es Simplified taper pin Old Glass-Cutter Is Wrench for Small Nuts WRENCH for small nuts, such as are _ found on typewriters and other small machines and instruments, may quickly be CUT HERE ' Making a glass-cutter into a wrench made from an old glass-cutter. Cut off the point with a hacksaw as shown and, if necessary, file one of the square openings to fit the size of nut for which it is to be used.—R. L. JOHNSON. Popular Science M onthly 3 Indoor Teeter Provides Fun for Kiddies EEPING iittle tots busy during a long spell of bad weather is a problem that is easily solved by providing a play- ground with interesting furnishings. A teeter such as shown in the picture will keep the youngsters satisfied and give them exercise at very little cost. An attractive feature of this teeter is that it can be quickly put together or dismantled, and therefore may be stored in the attic ora closet. If no regular playground is avail- able, it may be set up in the kitchen or bedroom, because there is nothing about it likely to injure either floor or finish. A plank 2 in. thick, 12 in. wide, and 6 ft. long makes a fine teeter-board if all the rough spots are smoothed and the edges rounded. The finish may be either painted in bright colors such as chiidren like, or varnished over a coat of shellac. Strips of carpet are used as seat-pads. Each handle of the teeter is 1 in. square, 12 in. long, and rounded each side of the center. The handle posts are 2 in. square, 15 in. long. The upper end is rounded, and square l-in. holes are chiseled to take the handles. The handles are inserted in the posts and secured with sixpenny casing-nails. The posts, in turn, have 1\%-in. tenons at their lower ends to fit mortises in the plank. After the posts are fitted, drill 14-in. holes in the tenons as close to the under side of the plank as possible. and make pins that will fit tightly. It will be easy to slip out the pins, pull out the posts, and pack all away in a small space. The teeter axle is made from a piece of 2 by 4 in., 24 in. long. For 5 in. at each end this is rounded and smoothed with fine sandpaper. It is bolted to the teeter-board at the center, with four 5-in. bolts, washers, and wing-nuts for quick dismantling. Two uprights 2 in. thick, 6 in. wide, and 2 ft. high are required. The upper ends are rounded, as are all the edges. The 2-in. axle-bearing holes are 6 in. from the upper ends and drilled in the center of the up- rights. They should be carefully smoothed out and painted with melted, paraffin. By J. Horace Van Nice drilled in the lcyer end of each upright as shown below. Square 2-in. holes for the body-brace tenons cre chiseled 10 in. from the lower ends in tle center of the uprights. For the body brace use a piece 2 in. thick, 6 in. wide, and 2 ft. long. The ends TANDLES SS “RINT carpet” fi x a BASE BAR This teeter is quickly taken apart are cut 2 in. square for a distance of 4 in. to fit into the square holes in the uprights, Four bolt-holes are © and they are then drilled for pins just asin ~ , the case of the handle-posts. The two base bars are 2 in. by 6 in. pieces, 4 ft. long, tapered from points 6 in. from the center to the ends, where they should be three inches wide. Bolt-holes are drilled at the center to correspond with those in the lower ends of the uprights. To put the teeter together, first put the handle-posts in the teeter-board, then fasten the axle to the teeter-board, taking care to put the nuts on the bottom side where the children will not be apt to catch against them. Slide the uprights over the - ends of the teeter axle and body brace and pin the ends of the brace. Last of all, bolt on the base bars, fastening the wing-nuts inside as before. The advantages of the teeter are its reliable strength, the quickness with which it may be assembled or dismantled, and tle continual pleasure it gives the children. This Exerciser Is Made from Leftovers HE four rollers of this hand and fore- arm exerciser are cut from a broom handle. In the ends of three of them 3¢-in. 4 TELL LLL a CUT FROM BROOM HANDLE :§ a 2> > INNER TUBE NO.4 COPPER WIRE i How the exerciser is made and used holes are bored 34 in. deep; in the other a similar hole is drilled all the way through. The frame is made of a 27-in. length of No. 4 copper wire, bent as shown after one roller has been centered upon it. The ends are left straight until the other parts ha been assembled. | A strip of rubber from a discarded inne’ * tube, 334 in. by 12 or 13 in., is made into a elastic belt by lapping the ends 1 in. ane cementing them ogether. When thor! oughly dry, the belt is placed over one of the remaining rollers and two wires 5 in. long are looped in such a way that they will hold this roller and the other center roller in a fixed relation to each other, although free to slide on the guide wires; The ends of the frame are then bent to secure the fourth roller. As thehands and wrists become more muscular through using the exerciser, the elastic band may be shortened. —T. R. HART. Reflected Light at the Bench DDITIONAL light on the vise may be obtained by placing a mirror on the wall back of the workbench in such a position as to reflect the light from ? window. This will be particularly helpfu in a cellar or other comparatively dark workshop whenever fine and accurate work has to be done on small parts.—C. W. T. a4 a, be a '