Popular Science Monthly 1920-07: Vol 97 Iss 1

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EE 25 Cents Reg-USPatOft Cup Racing Becomes a Science—See page 17 Founded MON’ HLY /872 4 tions & Mecha 2w Ideas in Automot Wireless—Inven . MiP titd EEO

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ee ee 313 “Like yours—and for 50 cents LESS.” “Yeah? Me for Topkis after this!” STUFFY night in the narrow confines of the _ “sleeper,” then—oh, boy!—the dash for the a washroom and the cool, clean suit of Topkis Athletic Underwear. Topkis? Yes, sir! Topkis—with its loose- cut lines, its featherweight. nainsook that rests ever so lightly on your shoulders and barely touches you elsewhere. Topkis—that is made with the care and stitch- strength of the individually hand-tailored gar- ment. Topkis—that sells at the most reasonable prices! Yes, actually. Unions at $1.65, also shirts-and-drawers at $1.00 the garment. At the low Topkis price, you'll want to buy a half-dozen suits ata time. Look for the red- diamond label. TOPKIS BROTHERS COMPANY WILMINGTON, DEL General Sales Offices, 350 Broadway, New York City Also Makers of Women’s, Children’s and Boys’ Athletic Underwear ty tty eeeetee> (ue Athletic Underwear Copyright 1919, Topkis Brothers Company aes | ee So

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Popular Science Monthly & Oat oem = Dance to the music of famous bands and orchestras—on the Victrola The very latest and most tuneful dance numbers, played by musicians who are past masters in the art of delighting dance lovers. All the dash and sparkle and rhythm that make dance music so entrancing. And always ready on the Victrola Hear the newest dance music at any Victor dealer’s. Vic- trolas $25 to $1500. New Victor Records demonstrated at all The Cabagpe wnt lp Shareenes sare a dealers’ on the Ist of each month. sage pA rer ell VICTOR TALKING MACHINE CO. Camden, N. J. Victor Talking Machine Company Camden, New Jersey ee pee TE ne FT

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AVOIDING MISTAKES MEANS SAVING MONEY. , GET VOL. 5 —OUuIck Your name on a post-card will do. When Every- body is Urg- wi, ing You to =\"Build Now,’ now is the time of times to BUILD RIGHT. We manufacture Cypress lumber—and are proud of that fact. BUT—we don’t want you to use Cypress except where Cypress, ‘*The Wood Eternal’’ is dest for you. PROBABLY THE BEST THING FOR YOU TO DO is ro wwrite us for a copy of Volume 5 of the -ternationally famous Cypress Pocket Library. AND PROBABLY YOU WOULD BETTER “DO IT NOW.”’ You might as well ask for Vol. 5, and at the same time ask for Vol. 1, which contains a full list of the 40 odd volumes in this Library (which has become a sort of American Lum- ber Classic) and which also contains the una- / bridged U.S. Govt. Rept. on “The Wood Eternal’’—what it is, and why you need it— and with some ideas as to why you have to insist on it to get it—also why it is so well worth insisting on. (That’s the only way to get anything worth while—isn’t it?) Let our ALL-ROUND HELPS DEPARTMENT help YOU MORE. Our entire resources are at your service with Reliable Counsel. Southern Cypress Manufacturers’ Association 1249 Hibernia Bank Bldg., New Orleans, La., or 1249 Heard National Bank Bidg., Jacksonville, Fla. ‘ e Insist on —_— Cypress at your local lumber dealer’s. If he hasn’t it, LET US KNOW mapas « es Popular Science Monthly pular Science Monthly | JULY, 1920 Volume 97-No. | CONTENTS AERONAUTICS Next! The Aerial Freight Train. . awe 24 Spotting an Airplane by Sound Waves..... 36 Dictating Letters in an Airplane by Telephone 42 He Makes the Weather Pay...... 44 Customs Officers Look for Smugglers in the Air 56 Hanging by the Neck From an Airplane 57 Training Aviators With Terra Cotta Bombs 69 FOR THE FARMER It Gathers Up Stones in the Road....... 34 Scooping Up the Grasshoppers........... 36 HOUSEKEEPING MADE EASY Churning Se Easy Work! ... 2... .....60006.5. 42 Sweeping Dark Corners by the Light of a Flash- Oe ee Se re eee The Baby’s Carriage with Variations.......... 56 INDUSTRIAL PROGRESS Build Your House Out of Your Own Back Yard 23 Balloons Are Substitutes for Storage-Tanks.... 23 How to Test a Safe’s Strength................ 26 Sanding by Compressed Air.................. 26 Learning to Fight a Switchboard Fire......... 27 No More Trouble with the Machine-Tool Oil- EOS SEE Se ec re 27 Building an Excavator on the Spot........... 36 The Aerial Cable is Used for Transporting Timber 37 Make Your Own Concrete Blocks ............ 41 He Wears a Hand Shield ee Preserving Food Forever with Gas 48 Ready-made Holes are on the Market Now. 50 Using X-Rays to Reveal Flaws in Sheets of Mins 50 How Science Settles Disputes for the Business Dn Re ee eee ce oe, Se Safety First and Second in This Machine....... 54 Testing Drinks for the “Kick” ............... 54 Grain-Dust Explosive? Watch It Flare........ 64 ¢ Ne Ce 68 How Much Water is in the Milk?............. 71 MEDICINE AND SURGERY Hearing Wath the Eyes... -.. - 0. oes ees 35 Treating Patients at “Mr. Dooley’s’’ Hospital ES a iS aos ee a ee eee 50 (Continued on page 4) Copyright, 1920, by the Modern Publishing Company PoPULAR SCIENCE MONTHLY is issued monthlv. Yearly subscription in the United States, $3.00. Canada, $3.50. Foreign, $4.00. Single copy, 25 cents. PoPpULAR SCIENCE MONTHLY may be had at all news- stands in the United States and Canada; also from tke International News Company, London, and at Bren- tano’s, Paris. Advertising rates on application. Forms close the twentieth of the second month preceding date of publication. Entered as second-class matter Dec. 28, 1915, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post Office Dep7rtment, Canada. The contents of this magazine are copyrighted and must not he reprinted without permission. H. J. Fisher, President; R. C. Wilson, Vice-President; O. B. Capen, Secretary and Treasurer. Modern Publishing Company 25 West Thirty-ninth St. New York City a oll a te an EE ce TE a) > pet ol

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ome mle it ts Popular Science Monthly July, 1920; Volume 97, No. 1 25 Cents a Copy; $3 a Year Waldemar Kaempffert, Editor Published in New York City at 225 West Thirty-ninth Street IR THOMAS LIPTON has come S to this country with one of the most remarkable and sensation- ally radical challengers that ever crossed the Atlantic. Yachting ex- perts who have seen the hull of the Shamrock IV agree that she Racing for the “Amer When sport becomes a science By Joseph Brinker Vanitie will race. These yachts re- semble each other to a far greater extent than either one resembles the Shamrock IV. Both of the American boats are approximately 75 feet on the water-line, the Vanitie being the Ica S$ s 9 Cup larger when measured by the extent of the part that overhangs the water- line dimensions. ‘ The Vanitie has the larger sail area, carrying 9,465 square feet of canvas, compared with 8,188 anne feet of sail-carried by the Reso- lute, which is slightly nar- is perhaps the lightest and yet the most powerful Brit- ish racing creation that has ever visited our shores. The features of design that stand out conspicu- ously are the extremely long keel; the full form of the hull in the bow and stern sections; the bulge of the sides of the hull inward at the top or deck; and the un- usually lofty sail rig. The hull is of the lightest com- posite construction, the planking being laid in three plies with the two inner layers placed diagonally. The outer layer of the plank- ing runs longitudinally. Because of the long keel, with the lead placed low, yachting experts predict that the best chance of suc- cess of the Shamrock IV lies in a strong offshore breeze. Then her great sail spread will drive her through the water at a high speed. In light breezes the chances of winning are not considered so good, because her large keel will present a big area of wetted surface, and the “‘skin”’ friction be- tween it and the water will tend to decrease her speed. Against the Shamrock IV either the Resolute or the © Edwin Levick The racers coming head-on. From left to right are the Resolute, the Vanitie, and the Defiance. The Vanitie has a greater sail area than the Resolute 17 we a 72390 rower, but has a body that is more full beneath the ““water-line where the hull joins the vertieal sides of the keel: All three of the contestants are provided ‘ with ‘centerboards set in the bottom of the keels. No matter which boat is selected. to defend the Cup, she will compare in general ‘design more closely to her foreign rival than did Amer- ica’s earliest cup contestant, the America. In the span of seventy-nine years from the America to the Resolute and the Shamrock IV, there has been a_ remarkable evolution in the design of the racing yacht. The America was built to beat the sloop Maria, then the fastest pilot-boat in New York harbor. While she did not beat the Maria, she proved to be so fast for a schooner that the yachts- men who had ordered the boat accepted her and made ready for the trip across the Atlantic. The route was to Havre. It was made in sev- enteen and one half days. After watching the Amer- ica, with her widest beam amidships and fine lines fore and aft, the British accepted the American type of clipper

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bow. But, because of the deep Brit- ish waters, the hulls were deep and narrow. In America the conditions favored boats of greater beam and less draft because of the shallow waters. The British type is exem- plified in the Genesta of 1885, as shown in one of the accompanying illustra- tions, and the American type in the Mischief, which was built in 1881. Coming develop- ment was seen in the made so shallow that there was in- sufficient headroom below the deck for comfortable accommodations. These reasons lie behind the fact that all of the racing machines of recent years were broken up for junk after the completion of the races. The new rule and the formula by which the rating of the ‘yacht is de- termined includes the factors of sail Popular Science Monthly area, length, and displacement. The rating is determined by the formula:

L V Sail Area Vv Displacement Because the displacement factor is the denominator of the fraction, and because the larger the denominator the smaller becomes the final fraction or rating, it is seen that the new rule _ favors boats of larger Rating = 0.18

displacement. Other

Thistle, the chal- lenger for the Cup in 1887. She was wider in proportion, to her depth than: ahy pre- vious contestant. Then came the Val- kyrie I in 1893, with a fixed, finlike keel instead of a center- board, because a fixed keel can carry from sixty to ninety tons of lead. Finally the British type of narrow, deep hull gave way to the wide but shoal hull with a deep fin keel to carry lead ballast. The Reliance, an example of this type, with a

things being equal, the boat with the larger displacement will have the smaller rating and will re- ceive a larger time allowance. The Vanitie de- parts less from the old rule than the Res- olute. The Resolute has a fuller and deeper under-water body and is built more closely to the rule, as shown by her sharp ends, deep V sections, and large displacement. The Shamrock IV is a compromise between

water-line length of about 90 feet and an over-all length of 140 feet, carrying 16,000 square feet of sail—the largest ever carried by a Cup yacht—was perhaps the acme of the highly developed racing machine. But the Reliance and the Shamrock ITI were rule-beating freaks, which, as soon as the Cup races were over, were broken up on the junk-pile because of their extreme design, their unseaworth- iness, and the inability to get other boats to race against them in club re- gattas. Because these boats had de- veloped into freaks, the racing rules were changed. The Resolute, the Vani- tie, and the Shamrock IV, all with a water-line length of 75 feet instead of the 90 feet of the Reliance are far more wholesome boats, and will probably see many years of regatta racing before they are discarded. The old racing rule put a tax on water-line length and sail area, but on nothing else. Provided the yacht did not exceed 90 The first winner of the cup, the Amer-

N AX \ \ WN NS \ AY \ IY ASN \ ROY AY \ dM \

N \ BZ zz built with a full hull and extremely ica. Though a swift schooner in her long keel. The Resolute and the day, the boat does not compare in Vanitie could sail around her in circles, speed with the modern racing yacht because of their modern construction

the extremes of the Shamrock III and the Reliance. The Sham- rock IV is full ended, with a large sail area and a deep keel having a large surface in contact with the water. While the elements of yacht design are not expressed in so many words in the formula by which the rating of the Cup yachts is determined, they are present just the same. The re- sistance that a vessel encounters in passing through water is made up of three kinds—frictional resistance, wave-making resistance, and eddy- making resistance. Frictional resist- ance is that due to the friction of the water on the under-water surface of the vessel. It de- pends upon the area of the surface and the nature and shape of the surface. This resistance is known as skin friction, and forms a large part of the total resistance at low speeds. It is, of course, decreased by cut- ting down the area of the hull in contact with the water. This area is com-

feet in lenzth on the load water-ling, she could be as broad and deep, and as long over all, as desired. The boats built under the old rule drew too much water for cruisers sailing in the shallow American harbors. To save weight the hulls themselves were AX N Compare the America, which won the race in 1851, with the Resolute. While the America was about 13 feet longer than the Resolute on the water-line, she was less in length over all, on account of the extent of that << EeEEE EE QW @dh“e-. Mdi_-_ AM A OT_T- SO oN *

g - . OW part of her construction that “overhangs” the water-line measurement. The America is indicated by the darkened portion, to show the differ- ence in the shape of the hull and the relative sail area 18 monly called the “wetted surface.” The speed of the boat depends upon the ratio of the sail area to the wetted surface. Without unduly reducing the area of wetted surface, it is the task of the yacht designer properly to proportion the ratio of the sail area to the wetted surface. Because the Popular Science Monthly

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July, 1920 skin friction is the most important re- sistance to the progress of the yacht through the water, that vessel with the larger ratio of sail area to wetted surface will be faster, other things being equal. In designing the, Shamrock IV, Nicholson gave her an extremely long keel. This greatly increased the area of the wetted surface, but also enabled him to spread the lead in the keel out longitudinally instead of building it up vertically. Hence the center of gravity of the lead lies lower, and this in turn means greater sail-carrying capacity for the same weight. Be- cause of this low-placed lead and great sail area, which increases her speed in strong breezes, yachtsmen contend that the Shamrock IV will have her best chances of winning in strong winds. At lower speeds in light airs, where the wetted surface and its skin friction are the most important considerations, the Lipton yacht will be at a great disadvantage compared with either the Resolute or the Vanitie, which have a much smaller area of wetted sur- face. The bottom length of the keel of the Resolute is only about half L a sa / RESOLUTE 6. RELIANCE V-VANITIE R- RESOLUTE Pa AS R Vee ANCE RELIANCE A comparison of the rig and sail plan of the Resolute and the Vanitie, with that of the Reliance, which defeated the Shamrock III in 1903. The Re- liance was 90 feet long on the water- line and 140 feet overall. The water- line length of both the Resolute and the Vanitie is 75 feet. The Reliance carried 16,000 square feet of canvas. The Resolute carries 8,188 square feet of sail, the Vanitie, 9,465 square feet that of the Shamrock IV. Although changes may be made in the rig of the Shamrock IV before she crosses the starting line on July 15, she may carry approximately 10,000 square feet of sail area as compared with the 8,188 square feet of the Resolute. If these ratios hold true, the Shamrock IV will probably have to give the Resolute three or four minutes of time allow- ance. This is an important factor, for-on-at least one occasion the Ameri- can defender of the Cup beat the British challenger on time allowance. That was the race between Columbia and Shamrock II on October 4, 1901, when the Shamrock II actually beat the Columbia by two seconds on elapsed time, but lost the race by forty-one seconds because she had to give the Columbia a time allowance of forty-three seconds. Some idea of the tremendous sail spread of the Resolute may be gained from the fact that if her sails were made from ordinary bed-sheets, fifty- four inches wide by eighty-one inches long, it would require 270 of these sheets, sewed end on end, to give the equivalent sail area. The Resolute at the left and the Vanitie, at the right, cutting gracefully through the water. The “lines” of the sails are calculated to lie perfectly straight in the wind in the speed of the race 19

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Popular Science Monthly Cup Famous Contestants for the “America’s” The America

The most notable peculiarities of the America were in the sharpness of her bow and in the shape of her hull on the sides which rose from the keel in straight lines, each pair forming a sharp V.. She was only 94 feet over all; 88 feet on the water-line; 22 feet beam, and had 11% feet maximum draft

Wa EEL Yj au

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The Mischief

WILLE. WT The Mischief was an iron sloop, much smaller than the a eo See water-line of 61 feet. The Mischief defeated the Canadian challenger, Atalanta, in two out of the three races sailed The British Cutter Cenesta The British cutter Genesta was built along entirely new lines. In light winds she was an easy mark for the Puritan, the American defender, but in a heavy blow showed such sea- worthy qualities that her last race with the Puritan was con- sidered one of the best Cup races of any sailed up to 1885

The Scotch Cutter Thistle The Scotch cutter Thistle marked a new departure in British challengers. She was 108 feet over all; 86 feet on the water- line; 20 feet beam and 1334 feet draft. Her underwater hull near the bow was well cut away and she carried 55 tons of lead on her keel. Inside she carried ten tons of lead

The Valkyrie The Valkyrie I was the prototype of the present day racing yacht with long overhangs at the bow and stern. She was the biggest of the challenging sloops up to 1893 and was 126 feet over all, 85 feet on the water-line, and she had a draft of 1614 feet. She carried 10,042 square feet of sail

je > Se Y Y The Vigilant i j/ j/ V// Yj Y 7 / Y jy" Gp a The Vigilant which defeated the Valkyrie I SaaS Y eae |

She was designed and built by Nat Herres- hoff. Her sail area was 11,272 square feet

‘ - ! LF ZZ at Y/ V// The Columbia . i Yj a The Columbia, which defeated Sir Thomas

| - / Z ] Lipton’s Shamrock I in 1899, was the most UY Yy Yyy / Hy pronounced skimming-dish type of hull up |G Hi to that year. The hull proper with a beam

Ze @ of j1 st 24 feet had a depth of only 7 or 8 feet Yj TELE” \ 2 TZ ae The Vanitie One of the contestants for the honor of de- fending the America’s cup this year, the Vanitie, has 65 tons of lead in her keel and draws 1334 feet of water exclusive of a small centerboard. She is 119 feet in length over all, but only 75 feet on the load water-line

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_ = The Shamrock IV Ly Y yy

GY ; In his fourth attempt to win the Cup, Sir Thomas Lipton has brought over in Sham- rock IV one of the most remarkable challen- gers built. Her keel is extraordinarily long, measuring about 35 feet along the bottom

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July, 1920

4 .

The race-course for the yachts off Sandy Hook. The first race for the America’s Cup will be held It will be a race fifteen miles to wind- ward and return, as indicated by the dotted lines in the center of the triangle. on July 15. While the present racing rule gives a bigger rating the longer the water- line length and the larger the sail area, the length L in the formula is not the water-line length, nor does the rating increase in the direct ratio of the sail area. The sail area rating increases as the square root of the area, and it follows as a matter of course that four times the sail area would double the rating. The cube root of the displacement, being the denomi- nator of the rating fraction, helps to hes - Z eae FSi ye i. P lle. - de wet bie a am da hee ee = 8 “ ee ee . + S Shwe srantthtiey . & SS ‘ eg

Three out of five on a = : rai aay one S cates un atl ¥, ‘ ¢ ene c > - ““LIGHT-SHIP Keo 2h 7 ~ START AND ~~. L0 iy, FIN!SS <= tés

races must be won. ATLANTIC s OCEAN sy ed i —

_- <3" - 15 MILES TO) - _-<-7\ WINDWARD pe _ _\ AND RETURN (@) gq 5\ oN

The second and alternate races will follow the triangle, each side of which is ten miles long, making the tetal length thirty miles. These races will be sailed .n Tuesdays, Thurs- days, and Saturdays until the winner is decided which includes the load water-line length plus one-half the excess of the quarterbeam length over the _ per- centage of the load water-line length given by the formula: P=100—+V/]oad water-line length The formula quarter-beam length is de- termined as shown in the accompany- ing sketch, and is employed to prevent beating the rule by freak designs in the bow and stern overhangs. The rating, as determined by the

give a smaller rating as_ the displacement in- creases, and this means_- greater seaworthiness of the boat. The length L in the formula is not the water-line length, buta corrected length Sail area, displace- ment, and water-line length are considered in determining the rating of a racing yacht, with the time allowance that must be given a vessel of smaller rating. The water-line length is not measured on the load water-line, but is a corrected length ®\

'y ae, BEAM LENGTH————» ' which includes the T load water-line length +; 1/10 BEAM OP plus one-half of the 1 | WATER-LINE excess of the quarter- beam length, divided by a certain percent- age of the water-line

Sail area, displacement, and water-line length length determined by another formula. The quarter - beam length is measured as indicated in the sketch at the left WATER-LINE DECK above formula, gives the time allowance, which - depends upon the assumption that a yacht of racing measure- ment FR will sail a nautical mile in the number of seconds shown by the formula: a a ere oR nm A

re ~ as OATES

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What more could be de-

> sired, on the day when the

DECK-LINE

i —+ The chart shows the narrower width of the Resolute compared with the Vanitie, and the fullness of lines of the Resolute under water. The lead keel is higher than that of the Vanitie. The keel of each boat is three feet wide at the base TOP OF LEAD, RESOLUTE TOP OF LEAD VANITIE race begins, than a “spank- - ing” breeze, a sun-glistening ’ sea with waves of just the right size to add spirit to the scene? If the present race is like its predecessors, a pro- cession of tugs, launches, - motor-boats, excursion steamers, and all manner of craft will pass through the i Narrows to take the throng w— of yachting enthusiasts Popular Science Monthly reserve. It may be that no one will | know, for a while, who the winner may be. If one boat skims the line a frac- tion of a minute before the other, this does not mean that it has actually won the race. When the rules of the “game” are applied and the proper “weights” allowed, the judges will announce the winner. Not until then will the curiosity of the crowd be satisfied. But cheering will not be hindered on account of that. It is often well for those on each side to enjoy the pleasures of success, and then to suffer

Experts agree that the Shamrock IV is the lightest and most powerful British racing boat ever built. The chances of winning the race will de- pend upon a strong offshore wind and “good sports” out to a point of vantage. It will be a gala occasion, a scene of color and life. ; In the staked-off course the beautiful yachts, their sails presenting lines that are straight and beautiful in the sunlight, will be seen. Tilted in the wind, cutting through the green water, glistening where the waves have split around their bows, the yachts will speed sands of eyes will be focused

WORKING TOPSAIL the pangs of disappointment; for then everyone is given a chance to prove himself a good sport. But the man who laughs last is the one who wins the bet, and he will have to await the decision of the judges who have considered every factor and ap- plied the mathematics of the rules. Further zest is added to this year’s races because they mark the thirteenth attempt to lift the cup, twelve made by British challengers and one by the Canadians. If Sir Thomas be- lieves 13 is his lucky number, who can say but that when the mist lifts off the Sandy Hook course some fine morning in July, the cup will be on its way back to England? It has re- mained continuously in this country for 69 years or since that memorable day in 1851 when the fleet America out- sailed the fastest that Britain could produce.

NO 2 JIB TOPSAIL NO.) JIB MAINSAIL TOPSAIL

MAINMAST t

upon them through glasses 800M) — - from deck and shore, wher- r —f ‘ f—4 STAYSAIL ever a glimpse of the course _ = can be obtained. V COUNTER MARTINGALE 7 Whether the Resolute, the BOWSPRIT Vanitie, or the Shamrock IV will be first to reach the final stake, this yacht race per- haps more than others will arouse international interest in yachting. But the rules of the race will make the crowd hold its decision in 22 A diagram of the sails of a racing yacht. The shape of these sheets of canvas are cleverly designed to respond to the wind and air resistance. It is the manipulation of the sails combined, with their area, that speeds the craft through the water. The mainsail of the Vanitie weighs about one ton and ‘the top of the mainmast towers more than one hun- dred feet in the air. The amount of canvas car- ried is almost twice that carried by the America

The “nw cal met: dist infil: Thi to s pres

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July, 1920 Build Your House Out

Placing squares of clay in frames, to be baked in- to adobe bricks

Adobe mud and straw, mixed to- gether, kneaded, placed in frames, smoothed, and dried, will turn into bricks with which houses are now be- ing built in Southern California, re- viving the method of old Spanish days OME seekers in Los Angeles are literally grasping at straws— and mud, Their slogan is “build your house out of its own back yard.” Due to lack of building materials, adobe clay mixed with straw, in Mexican fashion, is now being used in the construction of southern Cali- fornia bungalows. Mexicans knead the mud and straw with their bare feet. After it is prop- erly mixed they put it in frames, smooth it with their hands, and leave it on the ground to dry. One day in the hot sun will turn the muddy dough into bricks. These resulting bricks are so dur- able that they will withstand a pres- sure of four hundred pounds to the

square inch. Adobe is one of the most non-conductive materials known and thus houses made from it will not respond readily to heat in summer or to cold in winter. The bricks are put through a water- proofing process that removes the dampness sometimes found in adobe buildings. Owing to the large size of the bricks the houses can be erected in a very short time, and adobe houses last a long time. The Pala Mission was built of adobe one hundred and thirty-five.

of Your Own Back Yard years ago and it is still standing. Modern adobe structures may be fin- ished off in concrete to look just like other bungalows. But if owners prefer the picturesque baked clay finish, con- crete is omitted. A number of country homes of this type have recently been erected in southern California where, a in the old days of the te Spanish régime, homes were ‘built exclusively of the adobe clay. Since this material is plentiful in California, tuou- sands of p ople may soon be moving out there to build homes without encounter- ing the high cost of lumber.

Modern adobe houses. are sometimes finished with con- crete, which is an improvement on the old way. The new bricks undergo a process that prevents dampness in them Balloons Are Substitutes for Storage-Tanks

The illustration on the right shows one of the ‘“‘nurse”’ balloons used to store gas in chemi- cal laboratories. It saves the expense of metal tanks and can be conveniently man- : OW would you carry a large volume of hydrogen gas to the distant field where it is needed to inflate a dirigible or a kite balloon?” This might seem a problem difficult to solve unless the gas, greatly com- pressed, could be conveyed in metal aged by feeding the gas through atube. On the left is pictured the method of feeding gas from a “nurse” baloon through a sys- tem of pipes and tubes in the laboratory tanks. But the solution proved a simple matter during the war. The in- flating gas was taken wherever needed in small storage containers called “nurse” balloons, and from them fed into the dirigibles and kite balloons. These gas-bags are made of mate- 23 rial which will hold their original “‘gas- tightness’ for a long time and are cylindrical or spherical in form. The spherical types, nine feet ten inches in diameter, will hold 500 cubic feet of gas. <A cylindrical balloon 33 feet long and 10 feet 6 inches in diameter will contain 2500 cubic feet of gas. The peace time use of the “nurse” balloons is an interesting instance of the conversion of a war product into a commercial utility. In chemical laboratories it is neces- sary to keep various gases in storage. Metal tanks have been used, but are expensive. The use of nurse balloons in the laboratory affords a convenient method of handling gas. Small gas- companies are also using the storage bags for the same purpose, instead of erecting expensive tanks. The highiy combustible na ure of illuminating gas would make it an unsafe exper:ment to substitute gas- bags for metal tanks where sparks or inflammable material might fire the balloon. Means for providing cuffi cient pressure are also required in thi use of the gas-bag. | | t

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Next! Popular Science Monthly The Aerial Freight Train Will this latest project of aeronautics become a practical possibility ? By Adrian Van Muffling, S. A. E. MAGINE a string of airplanes, or I rather huge motorless gliders laden with freight, traveling over the trackless road-beds of the sky, led by a tremendous ‘‘locomotive-plane.”’ It’s a picture fairly staggering even to our rather sophisticated modern imagination. And yet, if reports from overseas are true, the scheme to employ an air- plane of enormous power to pull a number of froight-carrying - gliders is credited to no less experienced a man than Mr. Fokker, the Dutch aero- nautical engineer who developed the first high-speed flying machine during the war and thus gave Germany a temporary supremacy over her foes. 24 The aerial freight—at present still a figment of the aeronautical im- agination. But the world has grown accus- tomed to seeing impos- sibilities changed into a facts, and we should probably take it as a matter of course if we were to gaze into the sky some day and see the sight here pictured. The train is linked to- gether by the cable In justice to Mr. Fokker, it should be stated that he first offered his designs to the Allies, and did not enter into communication with Germany until he had been turned down by them. The most obvious difficulty in trailing airplanes lies in the method of starting and getting the trailers off the ground. Will they be placed ——— —— a |)— he! ee Jul: behi moti as tk Obv: the { great stant sudd resul to b othe: a pre stret eral get alter consi grou them so a meth of tl twee: accel tanec form invol Cond mate as th have migh one } laxin; happ equip cable ed ula,

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July, 1920 behind one another close to the “‘loco- motive,”’ and start on their journey as the connecting cable becomes taut? Obviously this method would subject the frame of each unit to stress much greater than it can be built to stand; moreover, the imposition of sudden and increasing loads would result in slowing down the motor unit to below its flying speed. If, on the other hand, the planes were placed at a proper distance apart, with the cable stretched between them, a field sev- eral miles long would be required to get up the necessary speed. Two alternatives present themselves. One consists in starting the units closely grouped with taut connection between them that could be paid out gradually so as to increase the distance—a method that is objectionable because of the aerodynamic interference be- tween the units. The other is to accelerate all trailing units simul- taneously by means of a moving plat- form or endless chain, an expedient involving a disproportionate expense. Another problem presents itself. Conditions in the air would vary materially between points as far apart as the various units necessarily would have to be. For an instant a trailer might travel a little faster than the one immediately preceding, thus re- laxing the connection. What would happen when the slack was taken up? The thought of having each “car” equipped with a reel upon which the cable could wind itself as required presents itself, the tension being kept constant by a compressed-air or spring arrangement after the fashion of the familiar trolley-pole retrievers. The weight of such an equipment would be likely to be equal to that of the aver- age aviation motor. Difficulties to Be Overcome Even with the most careful indi- vidual control of all units, it would be a very difficult matter to keep them traveling in exactly the same path. The slightest deviation, on the part of the motor unit, from a mathematically straight line would entail a side-slip- ping effect on the succeeding units. Moreover, the tractive effort exerted by the cable in a forward direction would vary with each change in di- rection, no matter how slight, and at no time could a constant pull be ex- pected for any extended period of time. That this would seriously affect the maneuvering powers of the train is apparent. But the greatest difficulty to be overcome is inherent in conditions that govern the relation of power and weight in airplanes. The greater part of the power developed by an aviation motor goes toward sustentation; the rest is absorbed by resistance en- countered in driving the machine. If the power be greatly increased the excess will go toward increasing the speed (and it requires roughly four times the power to double the speed). 25 An airplane has therefore no “tractive- effort;’’ that is, it is inherently un- suited to exert a pull. Now, the motor unit would have to lift itself first of all—no mean achievement if we consider the weight and size of the power plant required, and in order to give any tractive effort the power de- veloped would have to be far superior to that needed for flight, which is equivalent to saying that the machine should be able.to keep itself in the air at a speed considerably less than that of which it is capable; a condition which has not so far been realized even in the most modern types of airplanes. A Remote Possibility The weight and resistance encoun- tered by a large machine capable of carrying, say, five tons of freight would be much smaller (to a pound lifted) than that offered by five smaller planes of one-ton capacity, each in- volving a separate set of wings, struts, landing-gear wires, a second pilot, etc. Counting the weight and resistance of the motodr unit necessary, but not carrying a “useful load,’’ the power required seems to be at least eight times as much as if the entire cargo were concentrated into one machine capable of carrying it. This is an- other difficulty added to those men- tioned. These considerations lead one to the conclusion that the aerial! freight train is a remote possibility. SRN SNE GS EOE EA NS NOT a

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Popular Science Monthly

A load of bricks was dropped on it; then it was baked again. Afterward the safe was still intact, but it looked like this A safe was baked for two hours and then dropped from a height of thirty feet to the pavement How to Test a Safe’s Strength When it was opened at the conclusion of the test, the safe’s partitions sagged, but its contents were unharmed The trustful safe-maker was testing its strength and it went through the ordeal nobly to prove it Sanding by Compressed Air A SAFE has a reputation to uphold. It is supposed to (CHAINS keep an automobile from skidding and slid- protect its contents so carefully that they will come through fire and falls unscathed. But how can you be sure of this? One safe-maker decided to prove the worth of his safes by baking one of them, dropping it thirty feet through the air, hurling a load of bricks on top of it, and then baking it again. Before he put it through this set of tortures he lcaded it with books, magazines, and even some loose dollar bills. In the first baking of two hours the tem- perature in the oven was nearly 2000° F. Thermo couples showed a an interior temperature of 300°. When the safe was opened. the books were found slightly warped, but no serious damage was done. While it was still hot, the safe was thrown from a scaffolding thirty feet to the ground. A shower of bricks followed it. Owing to the heat, these dented the steel, but did no further harm. The safe was rushed back to the furnace and baked once more, this time for an hour and a half. The temperature within the safe hovered around the three hundred mark all the while. When it was taken out and opened, the contents —books, magazines, dollar bills— were limp but unharmed. The partiticns were sagging, yet un- broken. The safe itself was blis- tered on the outside and had a tendency to peel, but it was intact. Who can doubt the excellence of this safe?

ing when the brakes are jammed on in rainy weather. A train can’t wear chains, yet it is just as susceptible

when the brakes are applied and the tracks are wet. But a constant flow of sand from the locomotive to the tracks will take the place of chains. Alva A. Fryer, of Kansas City, Mo., has invented a new sanding device that works on the vacuum principle and consequently insures a smooth, even flow of sand. The sand is held in a tank at the top of the loco- motive. A feed-pipe that carries

In order to prevent slipping, sand is dropped from the locomotive to the railroad tracks by a sanding device 26 the sand from the tank to the discharge nozzle inclines upward slightly, and thus keeps the sand from pouring out until compressed air exerts its force. The com- pressed-air inlet is located at the tov of the discharge-pipe. When the air is released the force of it drags sand to the top of the dis- - charge-pipe and then speeds it on its way down to the tracks. In the ordinary gravity type of sander the sand is very apt to clog and stop the flow, particularly if itisdamp. Compressed air makes this impossible while it lessens the wear onthe parts. The operation of this device is not affected by climatic conditions. The sander is cast in one piece and is made of manganese iron. When it is necessary to clean it out or inspect the sand the ‘‘clean-out”’ plug shown in the illustration is re-

moved. Even when sand is com- paratively dry, it is apt to “bake” in the dome and must be stirred.

July,

Fa be would put i left < there instar of the Com, exhib Th body’ old s piece: the v hand! N | me gener spoili must upon must spon Th accor feren of w factic be pr was failed come of m pum} Bo whic] put | have new pum| pan} the il are | pum) suffic char

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July, 1920 This fire in a telephone switchboard was staged in somebody’s back yard in order to show night watchmen how to put out fires Wire-draped racks were erected at the fire- fighting exhibition. These were set on fire and the men took turns at putting them out F a telephone switch- board caught fire, would you know how to put it out? Perhaps you are never left alone with a switchboard, but there are many men—watchmen, for instance—who are. For the benefit of these men the New York Telephone Company recently held a fire-fighting exhibition. The company borrowed some- body’s back yard and placed in it an old switchboard and racks on which pieces of junk wire were hung. First the watchmen were shown how to handle chemical extinguishers; then Learning to Fight a Switchboard Fire small fires were started in the racks. The men took turns at trying to put the fires out. They used pails of sand, to begin with, since sand would not do as much damage as water. If the sand failed to put the fires out, water was used. If neither of them was effective, chemical extinguishers were used. When all the men had demonstrated that they could handle small fires, larger ones were started, and allowed to burn for some time before attempts were made to check them. In the case of the switchboard, for instance, a fire was started in the keyboard as well as in the wiring at the rear. The men were greatly in- terested in the exhibition and handled the apparatus very skilfully. The exhibition took place on Fire Prevention Day and was well attended by central office employees and real estate watchmen. More than fifty men were gathered in the Brooklyn back yard, and several of them were given an opportunity to show their ability at fire fighting. No More Trouble with the Machine-Tool Oil-Pump N cutting metals, the tools must be kept cool by means of oil in order to prevent the excessive heat generated by friction, from spoiling the edge. The oil must be pumped continuously upon the tool and the supply must be regulated to corre- spond with the cutting speed. This pumping has_ been accomplished by several dif- ferent types of pumps, some of which did not give satis- faction because they had to be primed each time the pump was started. Other pumps failed because they would be- come clogged by small chips of material getting into the pump-chamber. Both of these objections, which seriously affect the out- The objectionable clogging has been overcome by making no passages in the pump-chamber smaller than the inlet and outlet pipes. Thus anything that can enter the pump, will also pass throughit. Full pumping efficiency is se- cured because the impellor, the only internal working part, does not depend upon contact fits for its operation. Furthermore the outlet of the pump may be regu- lated to give a flow of fifteen gallons a minute, or it may be choked off to a single drop. The position of the intake and discharge pipes at the top of the pump does away with the neces- sity of re-priming the pump. - DISCHARGE , ) INTAKE por aT = 4 put of any cutting machine, . $ des, PUMP-SHAFT have been overcome in the ema GEAR AND PULLEY a DILPAN new type of centrifugal oil- pump shown in the accom- panying illustrations. Both the intake and discharge pipes are placed at the top of the pump. This always insures sufficient oil in the impellor chamber to start pumping. This pump for cooling tools by a con- stant flow of oil has its intake and dis- charge pipes on top; thus constant priming is unnecessary. Its flow may be regulated to fifteen gallons a minute, or to asingle drop according to the re- quirements of the work. There is no clogging since no passage in the pumpis smaller than the inlet and outlet pipes 27 | ‘ " ' — ‘i on Stetiiieetieetneeteen’ P Saou i ‘. (= r Ror ernment

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Popular Science Monthly Will Peat Ever Replace Coal? 4 ld hardl - As coal grows scarcer a machine oe ee . : ° valuable; yet, this for excavating peat is invented nica A fuel of the future @ + Peat is formed by the partial decomposition of plants in water, and is found in damp, marshy places. .-This new excavating- machine digs it up by means of buckets on an endless chain. The machine moves slowly along the top of a_ trench scooping peat from the edges When the buckets go over the top the peat drops into a tank, where it is thoroughly mixed and pressed. Then it is dumped into a conveyor and carried off to dry. With the aid of this machine twenty-five thousand tons of peat, cut into neat bricks, can be turned out for fuel each year This is the conveyor that spreads the peat out to dfy. The peat is divided into rows by knives at the ends of the conveyor. When it is dry it is cut into bricks for fuel While the buckets on the endless chain scoop up the peat, this string of trucks carries it to the drying-field. The trucks are mounted on tracks and are. propelled by a gasoline-driven motor-car 28 Ponular Seience Monthly

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~ July, 1920 The Way They Mine Silver in Peru They still employ the primitive methods that were in vogue in the days of Pizarro The ore is crushed by huge boulders that na- tives rock back and for- ward. Handles are loosely attached to the boulders and they en- able the men to work with ease. Peru has none of our labor troubles. Laborers are plentiful and they are willing to. work When the rolling stone has thoroughly crushed the ore it is dumped into a cylindrical tank about five feet deep and then water is added When the mud has al- most disappeared from the ore, the remaining silver paste is placed in cone-shaped bags of heavy sacking, to re- main until most of the water has dripped through an opening in the bottom A revolving wheel in the tank stirs the water and crushed rock together until they form a thick mud which is very rich with silver From the tank the ore mud is removed to a square box with a fine screen bottom. By pressing a lever, the work- man drops the mud-filled box into a tank of water. The mud becomes diluted and the fine silver dust drops through the wire screen The silver dust clings to the mud, and a second bath fol- lows in a ditch of running water. Again the silver drops to the bottom and the “ lighter mud is washed away The moist paste is finally spread out on the ground to dry. Then it is shoveled into large canvas bags, sewed in and carefully weighed. It is now ready for shipment t> European smelters 29

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Popular Science Monthly The Motor-Truck Helps the Railroad Speed up the box-car by the expedient of keeping it moving F the man whose income is but I $1,300 a year knew that he is pay- ing a tax of $80 a year, what would happen? Theanswerisobvious. But he does not know, and so he goes on paying $80 a year tribute to the box- ear that hauls his food, clothing, and other necessities. help to produce the necessities of life, nor does it benefit the railroads that bring the food to the city. Each year this tax reaches the huge total of more than $1,000,000,000 for the 20,000,000 families of the country. What is the reason for this loss? Compare ’40’s The modern freight-car. the prairie-schooner of the with the box-car of to- day, and you will find that a good team moved freight with 1.24 per cent. less efficiency than the car does today. A load of freight can be brought by rail 900 miles from Chicago to New York at a cost about equal to that of handling the same load from the railway terminal through the streets to the consignee. Freight Is Stacked at Terminals Inbound freight from Staten Island and New Jersey freight-yards costs every man, woman, and child in Manhattan al- most 61% cents a day, amounting to about $118 a year for each family of five. Two-thirds of this could be saved, and the cost of the necessary in- stallation paid out of the first year’s savings. Since 1918 there has been a great decrease of mileage made by loaded freight-cars, due to the shortage of cars. The box-cars that should be used to carry freight from one city to another are held for the storage of freight because of the tremendous congestion at the terminals of the rail- roads. The terminal costs are enormous compared with the transportation costs in every city. This fact stands out when we consider short-distance hauls. The actual trans- portation cost from Phila- This tax does not - By Latimer J. Wilson The Why of the H. C.of L. Do you know that it costs every family of five in New York city $118 a year be- cause of New York’s hopeless freight congestion? What can be done about it? Let the motor-truck help the railroads. This is the first of a series of articles that the POPULAR SCIENCE MONTHLY will publish from month to month on business uses of the motor-truck. The truck-bodies are unloaded and the contents checked from the telephone despatch which was received before the demountable body arrived delphia to New York, based on a maximum charge of 6 mills a ton- mile, suggests a cost of 60 cents com- pared with a joint terminal cost of $6! Instead of traveling at the rate of 20 miles an hour for 14 hours, making 280 miles a day, the average box-car covers only 26 miles a day. This is little more than an hour’s work as a vehicle of transportation., Railroad practice figures that a car will be idle ten hours a day, which leaves four- teen hours of usefulness. But the actual handicap imposed upon the car by modern methods of freight- handling allow it only one hour in- stead of fourteen as a carrier of mate- rial from city to city. The box-car is turned into a storage-room or a “‘trans- fer’ to be switched about in the terminal yards. Why There Is a Car Shortage Every large city has many railroad lines pass- ing through it. For con- venience, consider a city that has but seven non- competing lines. A freight exchange is taking place every day from one main terminal to the six other main terminals, ma- king a total of 42 carsin the transfer of freight. Let each line have but three sub-stations,—a very conservative number for a large city,—and there is a transfer between these stations and the main ter- minal, which keeps 21 cars going and 21 cars coming each day, a total of 42 cars. Add the two, and we see that 84 cars are involved. This trans- fer delays freight in the terminal yards three days or longer. This is an equivalent of 252 ears. Think of the number in- volved where cities have 20 or more sub-stations! The floor-space occu- pied by boxes, barrels, packages of necessities of life, or the machines for industry, or the tools for labor, on the station plat- form is an average of 200 square feet to the ton, or A demountable body being placed upon the truck which has driven into the “‘slip”’ especially adapted to receive trucks. Working height is gained by the lowered floor 30 a maximum of 290 feet. The box-car transfer de- lay is 72 hours. If loaded to § hou to con cars Her St the fro1 bui pro sol the ina elas con bee nat as» not nor old age tio} sch per

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July, 1920 to 9 tons it requires an average of 8 hours to move one ton from one station to another. When each of the 7 connecting lines has three stations, 42 cars cause the delay of 37,800 car-days. Hence the apparent shortage of cars. Spending Millions Isn't the Answer If the railroads could afford to scrap their present investments and spend from $50,000,000 to $500,000,000 in building huge central terminals, the problem, for the time being, would be solved. But as cities continue to grow these terminals would ultimately be inadequate. What is needed is an elastic system. One man in the United States has come forward with a practical plan. He is Benjamin F. Fitch. His plan has been tried on a large scale in Cincin- nati, Ohio, and found practical. Strange as it may seem, Mr. Fitch’s plan does not displace thousands of miles of tracks nor demolish acres of buildings. The old freight-house built half a century ago, as well as the latest terminal sta- tion, is substantially a part of the scheme. Here and there a few inex- pensive structures are added. Motor-Trucks to the Rescue The secret of Mr. Fitch’s success is the creation of a continu- ous transfer service. City streets, country roads, all become a part of his trans- portation plan. The railroad track system, which of econ- omic necessity must remain fixed, is opened to traffic for the actual transportation of material over through routes. The box-car as a transfer car vanishes, and the motor- truck takes its place, work- ing from the outside. The railroad managers of Cincinnati, after considerable study, concluded to adopt the Fitch motorized system. They figured that 66,862.5 cars would be released for through service; that 21.4 per cent. trackage would be released at the main stations; and that 122,660 square feet of increased realty would result. Inbound platform space would be _ increased 14.8 per cent., and outbound space would be increased in proportion to the operation of the station. There would be no congestion of freight, because the motor-trucks would keep up a continuous movement. To do this the stations had to be adapted to the particular requirements of their location, original construction, etc. Every detail that would permit the rapid movement of the motor-trucks was considered. The predicted sav- ing was $61,652 annually. but in prac- Courtesy Material Handling Machine Manufacturing Association A demountable body having been hoisted from the truck is lowered and un- loaded, the freight being transferred to other bodies to be routed over other lines A demountable truck-body being loaded prepar- atory to sealing and routing to a sub-station or to one of the main terminals for through routing tice double the saving resulted. Every motor-truck used in the system has a number of demountable bodies of steel and wood. The inside dimensions are 17% feet long, 8 feet wide, and 7 feet high. The capacity is 10,000 pounds. There are inter- changeableside and end doors, equipped with protection bars and sealing de- vices. The terminals and sub-stations are equipped with electric hoists. In operation a truck from which an outbound loaded body has been re- 31 moved draws into its as- signed location, and a loaded body is quickly moved into place and lowered upon its frame. Telephone despatch precedes the departure of the truck from the terminal, and by the time it arrives at the sub-station its contents are known. The body is de- posited upon the platform at the exact spot prepared for it. The truck is instantly ready to receive a freshly loaded body, and is driven around to the place where the exchange freight has been sealed for transfer. The motor-trucks do not stand in line, waiting to be un- loaded; they merely have to wait for the exchanging of their bodies. The average trip time for the average body load of 4.37 tons is 10 minutes. Computed on a car basis, the movement is one ton every 2.3 minutes. New York City’s great problem at present. engrosses Mr. Fitch. His solution of it considers the future. Thirty thousand tons of material daily are moved from Staten Island ~ and New Jersey terminals to Man- hattan; 20,000 tons a day move out through these terminals. It is esti- mated that an average of two-thirds of the cost movement of inbound freight could be saved if the plan of Mr. Fitch is carried out. This saving

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Popular Science Monthly After data supplied by the Mate-ial Handling Machinery Manufactu-ing Association in one year would pay for the installa- tion of equipment, not including the cost of terminal buildings. Mr. Fitch would arrange Manhattan in twelve zones, each of which would have a joint inland station, situated conveniently near the slip from which its freight would be received. The rail bulkhead terminals in Staten Island, New Jersey, and the Bronx would each have a system of stations so linked that freight could be moved freely by motor-truck from one to another. Inbound freight would be taken from the box-cars and put into demountable bodies of trucks and sent to the point of despatch nearest the Manhattan terminal slip. Out- bound freight would be handled sim- Here is a section of the ideal terminal building. afford the maximum efficiency of truck movement. ilarly. This would put into free movement the numbers of box-cars that are now delayed by their trips across the river to the piers where great congestion prevails. Saving New York from Herself Based on what has already been demonstrated in Cincinnati, it can be prophesied that the rates for the motorized interchange of freight will certainly not exceed $2 a ton between the transfer stations at the rail bulk- heads and the inland stations in Man- hattan. Such will afford short hauls for the shipper, the cost of which will 32 The slips are so arranged as to The trucks come in on one be about $1 a ton, making a total cost of $3 a ton on material inbound and outbound from Manhattan. The pres- ent joint cost is not less than $6 a ton, so here is saved $3. If one con- siders the saving on the inbound freight and deducts this from the cost of food, then #ather Knickerbocker should be able to save his box-car tax of $80 a year. This sum totals $45,000,000 as a net saving for shipper and consumer. The inland stations could be built on less valuable realty that is far back from the valuable water-frontage. The buildings themselves could be mace impressive structures. The lower floors would serve for freight-handling, July, sic wh: to gla Th son Sut dei tin

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July, 1920 SAW-TOOTH STALLS (TRUCKS UNLOADING) f side, discharge their demountable bodies, and go to the other side to receive loaded bodies. while the upper floors would be rented to industrial plants, which would be glad to find occupancy near a terminal. These rentals would soon make hand- some returns on the _ investment. Sufficient truck-bodies would be fur- nished all the stations to meet the full demands. Perhaps special ferries would in time be built to aceommodate the numbers of motor-trucks bodies that must: be brought ‘across the river to Manhattan. Vehicular tubes con- necting the island with the mainland will soon be built. In the system of direct routing afforded by the plan set forth by Mr. All of the “‘through routed”’ freight is sent through the central passage Fitch, instead of 1,514 miles of city streets being traveled to. distribute freight from the Thirty-seventh street yard of the Pennsylvania Railroad, the same material would be carried only 703 miles. A saving of fuel and wear on the motor-trucks will be the outcome of the twelve-zone system. To Make a Greater Port Today every pound of freight coming into Manhattan and every pound that is taken from the city must be carted through city streets. Long trips are made to the ferries or present terminals, filling the streets with 33 vehicles, some of which are only partially loaded. This causes great congestion of traffic and enormous waste of space.. The short hauls af- forded by the twelve-zone system will work every truck to its capacity on every trip through the streets. Instead of having many conveyances carrying short loads of freight, there will be a fewer number of vehicles to _ crowd the streets, but all of them will be doing their full.duty. Instead of 30 per cent of the piers of Manhattan being used by the rail- roads for freight stations, all of the city’s port facilities will be used for coastwise and oversea shipping. This will enable New York to make the most of its location as a national port.

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Ford tractors dre hitched to the broom part of old street-sweepers, six of these trucks doing the work of twelve teams. Water is carried in a tank, to sprinkle the street before the broom Hitch the Street-Sweeper to a Ford put the old horse out in the pasture and hitch the street-sweeper to a Ford, and it will save money for your city. This is the lesson taught by the motorized street-cleaning department of Albany, N. Y. Horse-drawn sweep- ers, and also man-power sweepers, have been supplanted by the motor- drawn apparatus. The change was wrought by taking away the front wheels of the horse- sweepers and connecting the sweeping part of the equipment with the tractors by means of a horizontal wheel or turn- table. This permits a flexible move- ment in the broom-trailer when the street corners are turned. It was nec- essary to change the gear or driving sprocket for the broom, to prevent it from revolving too rapidly with the increased speed of the motor-drawn apparatus. Pulled along by an old horse it turned slowly enough, but when gasoline furnished the motive energy the broom needed a speed regulator. A strip seven feet wide and from twenty-four to thirty-three miles long can be swept in seven and one-half hours with an average speed of five miles an hour. It is estimated that about twelve teams are displaced -in sweeping and sprinkling by five motor sweepers. The saving of time and labor as well as expense, is important. The sweepers carry a water-tank with a capacity of one hun- dred and seventy-five gallons. This little tractor is here pulling a cultivator; but it will pull nearly anything else just as well Popular Science Monhly =—\\_A Tractor for the Small Farmer ANEW tractor that does the work of five men or one horse is shown in the illustration pulling a cultivator and jogging along at a good speed. The belt-wheel seen in front makes it possible to use the six-horsepower engine for other power purposes than harrowing, seeding, etc. It .may~ be run at high or low speed and will oper- ate a saw, a pump, a sprayer, a dynamo, a cement-mixer, a fodder-shredder, a grindstone, a separator, a hay-fork, and numerous other pieces of farm machin- ery. And, what is more, it rolls from job to job on its own wheels and under its Own power. This iron horse eats only when at work and requires no attention when not on the job. It costs only a little more than a horse. Although designed primarily for the small farmer, it will be found exceedingly useful on the big farm. The ad- vent of this _ tractor marks one more step toward increasing the production of the nation. The small increase in cost of the new tractor is soon repaid through the amount of labor it saves. Also the driver may hasten the speed of an iron horse without a whip or the expenditure of energy in urging it forward, and the speed- ing up will not fatigue it. The tractor’s engine may be adapted to a variety of work. It Gathers Up Stones in the Road RUNNER Chains form a heavy net that sweeps the roads for stones W HERE large and small pebbles are collected loosely in the gravel of a roaa, they are usually scattered in such a way that it would be an irksome job to collect them by hand. A new stone-gathering machine is drawn by one or two horses. A series of chains dragged loosely along the road sink into the small depressions and grad- ually scrape together the peb- A pipe runs from the tank along the side of the car and terminates in a sprinkler in front of the rear wheels. A sand-spreading wagon is also hitched to a motor-truck for distributing sand where needed, and in the motorized equipment of Albany there is also added a street-flushing system. With the entire equipment a street may have the dust laid, then be swept clean, and afterward sprinkled, all in a single trip of the motorized “sweeper.”” Where flushing is required, the sprinkling ap- Se TERETE ile “My ¥ bles or stones. The obstruc- tions are then drawn into a pocket, from which they are deposited at intervals in piles at the side of the road. A pile of a hundred or more stones. represents the work of only a few minutes, when gathered by this machine. How much time would it represent expressed in terms of man-energy? One hundred stones spread over an area of 400 square feet, in a plot 20 feet square, places one stone in every 4 square feet. A man working at average speed could pick up these stones and paratus is readjusted to givea heavy flow of water, and the “sweeper” accomplishes this detail with its other work. pile them at the side of the The dragging chains of this stone-gathering machine draw in the loose stones, which are automatically collected in a pocket. When the pocket is full the rear gate Opens and the stones pile up at the side of the road 34 road in ten or fifteen minutes; but the machine with its dragging chains wil! do the work in a moment.

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July, 1920 A lone hermit carved these queer stone fig- ures in the shelving, rocky shores of the island of Rotheneuf, France, where he lives the Stone Carvings by a Lone Hermit IF you ‘believe in ghosts, then go to the island named Rotheneuf, in France. — It - is such a weird, unearthly ‘place that your chances of seeing a ghost-there ought to be good. A hermit has lived there for many years and he has carved hundreds - of strange figures ‘in the shelving, rocky shores. They look like petrified men, and most of them lie on their back staring at the sky with sightless eyes. ' They are supposed to represent Biblical characters, but .as portraits they are decidedly unsatisfac- tory. figures of the Aztecs unearthed in this country and in Mexico. .The entrance to the hermitage itself. is a rough stone wall on which are mounted - heads—not real ones, but stone ones—all of them labeled. ‘They are grotesque and might easily be taken for gargoyles. But the figures on the rocky hillsides are really the ghost-getters. Those that are not lying down are sitting up in more or less startled attitudes. A few figures stand on the hill-top. You can stand there with them if -you climb the rough stone steps. At the top of the steps, the hermitage stands, overlooking the strangely carved shore and the sea. Many visitors come to the island to view these carvings which the hermit keeps swept free of sand accumulation. But who will care for them when he is gone? It is possible that in future ages they may be discovered under layers of sand and geological deposit and solemnly In their crude art they suggest the - carvings of- pre-historic Egypt, or stone ~ VA A small mirror, marked by vibrations of a membrane with which it is in contact, makes these vibrations visi- ble by throwing a design on a screen in a darkened room The apparatus pictured here, visualizes sound vi- brations by variations in the intensity of the glow of a small electric light and by rhythmic fluctua- tions of sound vibrations Even the stone wall at the entrance to the hermitage is decorated with heads that hermit carved in leisure moments Hearing With the Eyes EAF-MUTES, if they are not suffering from a structural defect of the organs of speech, may be taught to speak, but their instruction is difficult and its progress slow. It has been facilitated by the in- vention of Mr. Lindner, instructor of deaf- mutes in Leipzig, who, assisted by the Institute of Physics of Leipzig University, . has evolved two instruments for visualiz- ing the sound of human speech. One, called a “vocal phonoscope,” has a circular frame. over which a thin mem- brane is stretched. A metal plate attached to the membrane bears a pointed pin or thorn. Against this pin rests a small plate of brass. The apparatus can be used only in a dark room. Words spoken into the funnel cause the membrane to vibrate. The vibrations are transmitted by the pointed pin to the brass plate resting against it. This plate has a ‘tiny mirror attached to it, upon which a ray of light is focussed. As the mirror is moved by the vibrations of the membrane, the ray of light, reflected by it, draws designs on a screen. The same sound, of the same volume pro- duces always the same design. Deaf-mute pupils soon learn to recognize sounds by the designs. Another apparatus, the “drum regarded as examples of twentieth century art! Cable Repairs HEN the submarine cable leaks, a call goes out for the big cable repair ship to repair it. Bringing the cable-ship costs con- siderable money. The telegraph operator at Guinayangan on the island of Luzon has trained his native crew to raise the undersea wire without its aid. He con- trived an ingenious set of props to hold the cable free of the water. phonoscope,”” does not require a dark room for its successful em- ployment. A small drum is sus- pended from two vertical supports. By means of a delicate electrical contact the vibrations of the niem- brane of the drum are transmitted to a small incandescent lamp fed by a battery. The variations in the intensity and in the rhythm of the glow are interpreted by the pupils and are used, by compari- son, as a means of correcting their own sound production. They soon Bolstering up a submarine cable on the shore of Luzon 35 become expert in producing similar variations.

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Popular Science Monthly Spotting an Airplane by Sound Waves DEVICE has been invented for locating an airplane at night by the sound of the engine. It consists of two vibrating planes mounted at a slight angle to each other on a revolving wheel. A sound wave receiver is at- tached to each plane and is connected with a corresponding ear piece, The operator adjusts the ear pieces and then moves the wheel back and _ forward. When it reaches the region where the sound is most intense, the operator knows that he has found the direc- tion in which the airplane is located. He continues to move the wheel slightly until the intensity of sound is the same on both sides of the device. He has then found the plane in which the air- plane moves, and it is a simple matter to send a searchlight over that plane until the airplane is located. The device may also be of use when the heavens are ob- secured by clouds and: an air- plane sails serenely out of sight in the clear ether above. The exact plane in which it moves may be ascertained. He’s catching grasshoppers with a hopperdozer. As he goes forward, the grasshoppers jump into the pan Scooping Up the Grasshoppers we you go on a grasshopper hunt you can catch the bugs by the bushel with very little trouble if you copy the man in the picture. He drives a leisurely team of horses across the field and they push before them a “‘hopperdozer.”’ Into it hundreds of grasshoppers drop every minute and drown. A“‘hopperdozer”’ is not so compli- cated as it sounds, being a Mere pan for holding water, with a wall around three sides. He’s listening to the hum of an airplane’s motor to locate it Building an Excavator on the Spot ONVERTING aa stiff-legged man into an acrobat would be a transformation scarcely more interesting than the changing of a “‘stiff-leg’’ derrick into a “‘drag-line”’ excavator. Having a mile and one half of concrete railroad embankment to build, William McIntosh, master mechanic, hit upon the idea of making use of the dis- carded stiff-legs from a steel derrick. He had them rebuilt into “booms” for the drag-line. These were 62 feet long and 20 . inches by 20 inches square in the cénter. With two of these improvised excavators the work of lifting gravel from the wet pit and dumping it into the dump-wagons waiting to carry it to the concrete-mixer was expedited. One of the excavators worked on each side of the embankment, manipulating buckets that held about a cart load each. The arrangement also proved very satis- factory in clearing out the stumps that covered the flat lands through which the work had to progress. Even the sawed-off trees themselves helped in the building operations. They were cut close to the ground, permitting the drag-lines to run over them, thus bringing them finally into the gravel pit where they were extracted by the excavating shovels. The makeshift excavator was proved to be an economic success. The improvised “drag-line’” excavator made from the “‘stiff-legs’’ of a steel derrick was used successfully in the Miami Conservancy District, where sixty-five thousand cubic yards of embankment were built with it 36

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July, 1920 suit-case. engineer. pockets in it. He looks like a traveling salesman ready to start on a trip, but he is really a traveling draftsman Open the lid of the drafts- man’s _ suit- case and you will find within books, a drawing board, and a bottle of ink Carry Your Tools_ in a Suit-Case is TRAVELING salesman.”; That’s how you usually dub. the man who carries a queéer-shaped But you may be wrong. The. draftsman, fy instance, now carries a Queer-shaped suit-case, and in it he keeps his tools. The suit-case was the invention of a Milwauke The cover of the suit-case has two holds a tool case and the other is used for triangles and curves. Above these pockets leather straps sectioned off hold small articles. One pocket In timber regions that lack the usual transportation facilities, aerial cable-roads are used to reach water-ways or railroads Cattle:Are Not Wearing Horns This Season “ ORNS off,’ is the new fashion for cattle. This is because horned cattle use their advantage over. those without horns: they appropriate feed, and terrorize their defenseless ‘companions. also a source of danger to attendants who feel them. The accompanying pictures show a strong chute for: confining the animals while they are being shorn of their ‘dangerous horns. One is driven into the small pen and. when it inserts its head in the stanchion, the lever is pulled down. A rope is fas- Her head is held between two stanchions that are moved by a lever handle They are tened around the animal’s neck and looped around the muzzle so that the head can be turned to one side while the horn on the opposite side is removed. The operation is then reversed to remove the other horn. Tar is smeared over the wounds to prevent infection. Bossie: is then liberated, to return to her eight-hour-day-job of chewing her cud. Dehorning clippers are used to remove the bayonets of young cattle, while a saw is employed for mature cattle whose horns are more tough and brittle, and - hence liable to splinter and resultin wounds. ’“ Bossie’s horns. will soon be gone— sawed off. She used them too much 37 The Aerial Cable Is Used for Transporting Timber SUSPENDED cable-ways are used in the western mining regions of the United States for conveying ore, supplies and workmen over difficult territory, across streams and valleys. In some European countries, with wild and heavily timbered areas of rugged topography and few roads or other lines of transportation, such cable- roads have made it possible to utilize the. rich stores of timber and fire-wood which had previously been inaccessible. Our picture shows part of a cable-way constructed in one of the heavily wooded mountain districts near the Drina River, which formed, before the war, the boundary line between Bosnia and Servia. Two heavy steel cables are stretched along a series of trestles, following a line as nearly straight as the topography of the country will permit. On these cables run trolleys by means of which the loads of long timbers or of fire- wood are transported from the loading stations to.the banks of the Drina River. The carrying crates, platforms or baskets, relieved of their loads, are carried back to the loading stations over the return cable. . The speed of the carriers is controlled by a thinner cable which is fastened to the carriers and runs over a drum pro- vided with an automatic speed regulator in the form of a fan-wheel. The surplus of the power generated by the pull.of the loads in their descent from the moun- tains is utilized for driving a saw-mill and other machinery at the principal station. Much speed is gained by this method of transportation . because dis- tances are covered in a straight line.

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bas Seca eget ea Popular Science Monthly Where Wading Is in Order ROPPING with a realistic shower effect from the branches of .a live- oak, which conceal the pipes, the water supply for this wading pool falls first upon a cement “island”? housing an aquarium of goldfish, and then cascades into the pool where Los Angeles children play. Pool and fountain were gifts of C. W. Sirch, their designer. s . ‘ © Kadel & Herbert The News in Six Inches ETTER Times” is coming—this is not bad grammar, as you will see later. And it will un- doubtedly assist in the Americanization of aliens. “Better Times’’ is a news- paper—a very small one, but a very good one. It is eight pages thick and each page measures four by six inches. The United Neighborhood Houses pub- ONE day a thousand years or so ago Chinese troops went against their enemies with a new and ter- rible weapon in the shape of a repeating crossbow. The weapon ONKEYS, like women, are not all chatterers. Some of them are quiet creatures who prefer silence to the chatter of their kind. Look at the sad and solemn monkey be- lish it every month and low. He belongs charge five cents a copy. to the group There is great need for a called saki paper like this one in these monkeys, troublous times of imported known Bolshevism. Many aliens came to this country expect- ing to find the streets paved with gold, and they need the aid of an encouraging newspaper to help over- come their disappointment. The lead- ing article in the first edition is an in- terview with Lieutenant-Colonel Theo- dore Roosevelt, in which he’: urges ‘in- creased support for the Americaniza- tion work that is being done by the neighborhood houses. In spite of its small size this newspaper contains illus- trations, including photographs. Progenitor of the Magazine Rifle He Seems to Have a Grouch 38 are about fifty years behind the Smokeless Powder : to Light Cigars ITH a cigar between his teeth -and a smile on his lips, the man above calmly gets a light from a grain of smokeless powder. He knows that he won’t blow up, since the powder is not confined. He is using a powder grain that would set off a four- teen-inch gun; yet it doesn’t harm him. Powder will not explode unless it is confined and its gases have no room in which to expand. Take the case of a fire-cracker. You light the fuse, and whentheflame hits thepow- der the firecracker blows into bits. Yet suppose the a is faulty and the cracker won’t go off. .If- you break it open, pour out the powder, and set a match to the pow- der, it will flame up in-~ silence—no damage done. It is probable, however, that a smokeless powder light will never be very popular with smokers. Few men could smile with the care- less unconcern of the: man.in the pic- ture while handling a tempermental high explosive in this informal manner. which was to supercede clubs, spears, and the single cross-bow, carried eight or ten small arrows in a magazine from which they dropped into the barrel to be discharged. for their sweet, gentle dispositions and their silent tongues. They have white hair and beards, but times in the way they trim their side- whiskers. And they part their - long, crimped hair in the middle. Popular Science Monthly

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July, 1920

The Night-Shirt of an English King ; Rot we “(FF with his head!’ a an When the court pronounced this sen- tence on Charles I of England there might have been reasons other than treason. For in- stance, the judges might have seen him in his night-shirt. It seems to have been almost crimi- nally unbeautiful. Charles’ night - shirt and his night-cap which are here shown were sold recently at Rushbrooke Hall,England,wherethey . were so long preserved. < ~~

x “im Min,

He’s Motoring. on $ Roller-Skates You press the button and then start to roll — that’s how you operate the new electric roller-skates. But the chief disadvantage is that all you do is roll— you can’t really skate. For the volt accumula- tor that gives the skates their power is located between them and fast- ened tightly to them. Before you turn on the power you regulate .a speed switch located on a small disk you carry in your hand.

The “Scooter” Likes Shoals “TOOK out there—you’ll: be on_ bot- tom!’ The old river-man might have saved his breath, for the boat to -which he shouted the warning slid over the shoal with never a bump, and ata high speed. It was Glenn H. Curtiss’s new: boat, Scooter, driven by an airplane motor and propeller. . tance. The Runaway Trolley-Pole Is Caught and Held ANG! Bang! The trolley car bumps across the railroad tracks and the pole slips off the overhead wire. The lights go out, the car stops, and a locomotive whistle sounds ‘in the dis- What a fine setting for a smash- up! -. However, a new pole guard, shown in the picture above, makes it impossible for power to give out even if the pole slips off the wire. This guard is a trough of woven-wire suspended over the trolley wire. Should the pole jump off, it will simply hit against the trough, which con- tinues to supply power. The car will pro- ceed on its way out of danger where the pole can be readjusted. “Hot Dogs” Kept Hot EVER again need the starving ball fan keep one eye on the game and cast the other despairingly in the direc- tion of the frankfurter—better known as the ‘‘hot dog”—stand. The Stevens fire- less frankfurter cooker will bring “ hot dogs, red hot,” to the bleachers for the convenience of the fans.

©. a JOON

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es te Sasa assaecee Lee ane Sos ee See a gerne eng eS 2H SPRING RING AND NAME » LOCKING PIN g Brand Your Name on Your Umbrella MBRELLAS are the favorite prey of petty thieves. Even people who would shudder if their honesty were doubted, will borrow and keep um- brellas without a moral tremor. Perhaps the rea- son is that most umbrellas lack individuality and might be anybody’s prop- erty. Sympathizing with umbrella losers, James Gilroy, of New Jersey, patented an undetachable umbrella ring on which is blazoned in large letters the owner’s name. This ring fits over the rib tips and keeps them in place, thus serving a two- fold purpose. It has over- lapping ends which slide one over the other, so it can be spread to slip on and off the rib tips. A Cider-Mill Made from an Automcbile Jack HERE’S nothing illegal about a private cider-mill, and you will find it easy to make. need is an old wash-tub, a jack, and some boards. Make a small cover for the tub and erect a frame over it. tub with apples, put on the lid, then insert the jack between the lid and the frame, and start jacking. The apples are squashed and the juice runs out of the tub. : ¥y * | Ry They Are Making a Buddha for Motion Pictures HEN preparations were being made recently at Universal City for the motion picture production of ‘“‘The Breath of the Gods,’”’ in which the Japanese actress, Tsuro Aoki, was to be starred, a huge Buddha, such as those found in temples of Japan, was constructed under the supervision of a All you noted Japanese artist, C. S. Ito. Fill the Shooting Cigarettes from a Gun OT a cigarette? Don’t ask an Englishman that question for he may pull a gun on you. He will aim it at your head and pull the trigger! When you open your eyes and find that you’re not dead, you will see sticking out of the muzzle of the gun the very cigarette you asked for. With a shaking hand you take it. This toy gun was meant originally for use on cigarette robbers who always borrow their smokes. 40 man. Popular Science Monthly When There Were NoLights o’ London N olden times when London streets were dark it was customary for “strong-arm” men to act as paid escorts for people out late. With flaming torches they led the way through the streets, and upon arriving at the house of the person they were guiding through the dark, extinguished their torches under an iron hood at- tached to the tall gate. In front of many of these old London mansions can still be seen the “link- men’s” extinguisher, the worthies who lighted the way being called “link- men.” In the picture one is shown at the gate of an old London house where it has been since Shakes- peare’s day. An Entomological Crown Uneasy lies the Head— HE crown the German ex-Kaiser upon great holidays looked like the one below, whichis studded with bugs instead of jewels. It was made br’ a disillusioned Ger- . He traveled far and wide gathering bugs for it. Red bugs represent the rubies of the original crown, while white bugs serve for pearls. Popular Science Monthly

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July, 1920 Cae | “Home” Is a Box-Car STRANGE sights follaw in the wake of great wars. Whole communities are disrupted, families scattered, homes destroyed, and all leave their curious mark upon the lands engaged in conflict. Hordes of homeless people must find a spot sheltered as best it can be, a spot which they can individually call “home.” But a box-car is an extraordinary place for domestic bliss! Several members of the “Iron Division” compelled to leave the Baltic sought refuge in a box-car. They adapted it with ingenuity to the condition of habitability, even making in it a place for the family pet, the dog. Here they wait to return to Germany. Make Your Concrete Blocks [NSTEAD of waiting for the expensive load of bricks delayed by the great short- age in building material, get one of these machines. and make a substitute for the bricks. The concrete is poured into a mold which has a movable bottom. The workman operates a foot lever which raises up the concrete when it has set sufficiently to be removed. The block is then easily lifted.off by hand. An industrious man can turn out four hundred blocks in a day without any great expenditure of energy. July, 1920 The “Ophir” Comes Home HE U. S. S. Ophir, a trans- port that was sunk in Gibral- tar Bay during the war, was raised by the United States navy and sent home under her own steam. An explosion followed by fire had caused the vessel to sink. With practically no repairs made, the badly damaged ship started bravely for home with a crew of six officers and sixty-eight men. Her decks were uncovered and full of shell-holes; only three boil- ers were working. When two days out from the Azores, the boilers broke down and the Ophir had to be towed into port. When the boilers were mended she started out again. But she ran into a storm and drifted around helplessly, miles out of her course. Finally the Ophir limped safely into Norfolk. Horses Motor to Races in Their Own Cars N°? longer will race-horses which are worth $10,000 or $15,000 have to be © trusted to the railroads for transportation. These valuable horses do not like shrieking whistles and grinding brakes of the trains. Racing steeds are nervous animals, so the .motor-trucks that have recently been devised to convey them, offer great advan- tages over railway trains for transporting the horses. 41 The modern motor box-car for horses is equipped with padded stalls and is electric- ally lighted. Four stable lads can travel in the same car. The horses can be more quickly loaded into their own compart- ments, and they can be more rapidly trans- ported to their destination, since the usual railroad practice of shunting cars is avoided. With this improved travel, the horses should be in their best condition when they arrive at the race-course. The nerves of the spirited animals are protected from the jar and shock of railroad travel, and the horses are not subjected to the nerve-rack- ing process of shunting in the freight-yards.

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Popular Science Monthly Dictating Letters in an Airplane by Telephone ‘TSE busy business man and his stenographer can turn Music from a Wild Carrot. _ Is Like That of-a Flute , -N actual music-making flute out a number of letters in the ae course of an airplane trip from New York to Washington. The “click! click!’’ of the little typewriter is completely lost in the roar of the propeller, and the words that are dictated would also be drowned if special telephone connections between the two persons in the closed compartment were not made. The helmet worn by each of the passengers cuts out enough of the engine’s noise to permit the easy dictation cf letters. Both compartments are electrically warmed. HE flax happy people. function. Churning Is Easy Work! ‘THs little lady should worry if her mother tells her to run along and churn the butter. She takes her electric churn into the parlor, hitches it to an electric light socket, turns on the switch, and the churn goes to work. The machinery of the elec- tric churn is made of spring steel which not only gives it extra strength, but great rust resisting power as well. The movement of the dash rod and paddle is that which has been used for many years in the hand-power churn. Where Work Is a Party combers ; It is the custom on the Iberian peninsula to make of work a gala Garbed in their best, adorned with bright gold ornaments, their. garments an array of color with gay embroidery, men and women meet to carry on the ordin- ary daily vocations. In Portugal, that of winding flax is usually given over tothe women. The flax combers inthe illustration are of the town of Vienna do Castello in northern Portugal. 42 ~ eighteen inches. long by _ three-quarters of an inch in diam- eter has been made from a hollow wild carrot weed. -The music which the wind whistled through the weeds, and which became instilled in them has been brought to life in. the flute by. the skill of the workman.’ He kept at his job until all-the tones of the in- strument were accurate. The fragile ends of the flute were strengthened with abhesive plaster. One end was tightly stopped with a cork and sealed with paraffin. The flute has a remarkably sweet tone. of Portugal are a He Wears a Hand Shield MEN who do acetylene welding often suffer from burned hands— the heat from the. flame is so very in- tense. But a new hand shield has just +f been invented by Charles S. McCreery, of De Soto, Missouri. It consists of a curved plate of non-heating material and .two wire loops through which the welder thrusts his middle finger. The ‘shield is not large but it gives the hand sufficient room to move in, and thefe is plenty of air space. The non-conduct- ing shield is made to resist the most intense heat.

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July, 1920 Sweeping Dark Corners by. the Light of a Flash-Lamp ‘+... “ TUST look at the dust here in these cor- ners of the room—why, you didn’t sweep these corners!” exclaimed an angry housewife when she saw how unfaith- fully her dutiful spouse had performed the task set for him. “Well, I’m not supposed to sweep where it’s so dark, I can’t see what I am doing!” he retorted. Then the lady had an idea. She got the electric flash-lamp and fastened it to the broom with two rubber bands. With this as a torch, no matter how dark the room, the corners would be well lighted where the broom reached them. At least there would be no excuse for not having them well cleaned. The lamp is use- ful for. janitors who work in dark basements, or housemaids who must carefully sweep dark halls. Keystone ; ; : o~ of ancient customs and careless sanitation. Dark Patch, Hunter of Elephants DA8« Patch is a dog of fighting blood. His master was attracted by his pugnacity and his intelligence, and pur- chased Patch when on a trip to London. When only eight months old Patch went to the Congo with his master hunting elephants and buffalo. Eighteen elephants were shot on the first trip Patch made. Returning to Antwerp from Boma, west coast of Africa, Patch became seasick, but when his master decided to take him on another expedition, Patch was overjoyed and displayed no aver- sion to boarding the steamer again. A third time he went and after nine months in the most desolate part of the Belgium Congo, returned with his master who brought with him thirty-eight tusks. Meat for a Turkish Market CCONSTANTINOPLE, the melting pot where East meets West, offers many strange sights - to the traveler. ‘‘What are in those cages that the horse is carrying through the streets?” Each wire cage holds a hindquarter of beef. If the wire mesh were not so coarse it might keep out the swarming flies. But Constantinople is a city The House of Hearts Has Heart-Shaped Furniture ““EJOME, Sweet. Home”: signs fade into insignificance before the home-loving outburst of Mrs. E. C. Calder who lives in Pasadena, California. Tables, chairs, doormats, in fact all the furnishings in her house are heart-shaped. Her bed, for instance, has a heart- shaped headboard, supported on both sides by bedposts carved to represent cupid’s arrows. The heart-shaped headboard is decorated with a heart- shaped picture frame in which two loving angels embrace each other. Mrs. Calder calls her hcuse ‘“‘The Pericardium” which, physiolcgical- ly speaking, means the membrane that encloses the heart and the roots of the great blood vessels. Perhaps we do Mrs. Calder an in- justice when we suspect her of an over-attack of sentiment. Her husband is a physician and she may be simply trying to advertise. Magnifying the Strains of a ’Cello (CONNECT a metal tube with the ’cello and then with a large metal horn, and the faintest sounds emitted by the bow will be better heard by the audience. The principle is that employed in “talking machines.’”” The sound-waves passing through the column of air are intensified in the horn and are projected into the room ‘as though emanating from the horn instead of from the cello. One is familiar with the sounds of a vibrating column of air in the pipes of a pipe-organ, or in a cornet. ‘The principle is iden- tical with that employed here, except that the ’cello’s tones are made more audible by the curved shape of the horn. In an or- chestra the deep notes of this instrument are intensified by its horn. © Keystone View Co.

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He Makes the Weather Pay _ The industrial meteorologist advises farmers and aviators ‘By Lee McCrae ANY a man lives “with his M head in the clouds,’”’ but none more literally than does Dr. Ford A. Carpenter, of Los Angeles. Yet he is a practical scientist and has been appointed industrial meteorolo- gist of the Los Angeles Chamber of Commerce. ‘“‘*Free air’ signs here in California are supplemented with free air infor- mation,” Dr. Carpenter laughed, re- ferring to his work. “I am the ad- visor of aviators, orchardists, engi- neers, farmers, surveyors, doctors, and manufacturers, and I am about the most industrious industrial manager youeversaw. Ihave recently charted the wind currents of southern Cali- fornia, established fourteen safe land- ing-places for aircraft, given a series of twenty-four lectures on climatology and kindred themes, located soap factories, a rubber plant, town sites, sanatoriums, and——”’ “Buzz!” interrupted the telephone - at his elbow. A moment later, in. answer to a question, he -was saying: “No, don’t go up today. Your pic-: tures would not be good taken under - present conditions. Wait until we have had a rain. Call me after that and I will fix your elevation. Dr. Carpenter’s balloon starting on a voyage of scientific discovery. Air lanes and landing places for aviators are deter- mined on these air trips powerful influences of air-currents upon agriculture. Dr. Carpenter dis- played photographs of Los Angeles and its suburbs, and told of the cli- matic survey made of the big Vander- lip ranch which enabled its managers to plant it scientifically. “T spent last night in an orchard,” he added, “rolling in my blanket for three hours’ sleep on the ground so that I could give the owner of the orchard data concerning early morning conditions in. his grove.” “And today you were lecturing at theuniversity on medical climatology.” “Oh, yes, but the trips into the country and up into the sky are so much recreation. The diversity of the work makes it possible for me to go three days and nights at a time without removing my clothes and with The very only a few hours’ sleep. Popular Science Monthly contact with the earth and the upper air keeps one healthy. : “In fact, medical climatology, linked up with aeronautics, is our next ad- vance along curative lines. Instead of doctors ordering tubercular patients to distant sections, breaking up homes and causing untold misery and ex- pense, they will simply send a bunch of them up in an airship to float at a certain altitude for so many hours a day. The effect will be marvelous. Our army aviators learned that their headaches’ vanished in their flights, that they could go up with a bad cold and come back without it. It will be my work and that of other practical meteorologists to determine the best strata for these patients. This must be done locally, since different sections are altogether different atmospherically.” Of aviation, Dr. Carpenter declared, “‘The airship—not the plane— Glad to tell you! So long!’ Then he went on: “That is a small sample of the work. I saved that young man a lot of expense trying to photo- graph Pasadena from the sky. It would have been time, trouble and money thrown away to go up today.” “Then you are a Weather Bureau plus.” “Exactly. Plus years of first-hand experimentation. I spent thirty-one years in Gov- ernment Bureaus from Port- land to San Diego, and on that experience I have built. Avi- ation now demands wind charts and definite air lanes. I am the first observer who has made systematic meteoro- logical studies while in actual flight, and so can instruct flyers to go along at a certain altitude to—say San Francisco, for instance—and return by another altitude in order to have the winds in their favor, and avoid mishaps and possi- bly death. Recently we spent with engine and all within the envelope, using the non-ex- plosive, non-inflammable gas, will be safer and more com- fortable than the present rail- way coach, so it will beajoyful as well as a beneficial trip ‘ into the blue. “Did you know that Kipling is the prophet of aviation? Along in the ’90’s he originated the term ‘air lanes’ and all but visualized present aeronautics. The traffic is ready, waiting; we have only to build the ships and map out our ocean to ocean highways in air as on land. That is my chief job now.” Amid all his daily duties, with their interruptions, this citizen of the air has found time to write fifteen books on scientific themes, to lecture in biological universities and clubs, to arrange the gold medal exhibit in meteorology at the.San Francisco Exposi-— tion, and to qualify as an international pilot of aircraft, the night in a balloon noting the movements of night air- currents.” Few people know of the Just after a thirteen-hour night balloon trip to gather data on air-currents, valuable to farmers as well as to aviators. Dr. Carpenter is at the extreme right in the picture. 44 ready for the license issued only to the favored few, which permits him to‘fly over all national boundaries.

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July, 1920 Grandpop Crandall—Inventor ‘of Toys. greatest technician of his kind in America He is probably the LMOST any afternoon in the A summer-time, if you happen to be walking on a certain street ’ in Brooklyn, you will see a veritable flock of children—boys and girls from four to eleven years old—sitting on a stoop, waiting and watching. And every little boy and little girl will have _ tucked under an arm the remnants of a toy-—a engine with a loose wheel, a go-cart that won’t go, or a doll with a smashed head. Every now and then one of them will By Herbert Asbury ment. They regard him as nothing less than a wizard “Grandpop can fix anything!’”’ they say. And Grandpop certainly can fix any toy that the ingenious mind of man ever contrived. He ought to be able to do that, because Grandpop is Jesse Armour Crandall, who has been inventing toys for seventy-five years. almost as big as a live pony, and sent it as a gift to the royal youngster who afterward became King Edward VII. It was the first hobby-horse in Eng- lar.d, and Queen Victoria wrote to Mr. Crandal! that it was a very difficult matter to induce the young Prince to stay off it long enough to eat and sleep and do his lessons. Mr. Crandall has made toys, too, for the children of American presidents. When Grover Cleveland was in the White House the toy-maker abandoned get up and slide down to the sidewalk, to look anxiously down the street. And then, about half past four o’clock—al- most always exactly at half-past four—an old man—a very old man, in fact, because he is eighty-eight years old, and he wears side-burns like those that adorned Horace Greeley—an old man turns the corner. Immediately there is a shout of ‘“‘Grandpop!’’ and the last fifty yards of the old man’s jour- ney is made with con- siderable difficulty, since there are boys and girls hanging to both hands, jerking at his ‘ coat-tails, getting en- tangled with his legs, and literally climbing all over him. And each one wants something: “Grandpop, fix my doll!’’ “Grandpop, lookit my engine! It won’t run!” “Grandpop, put a new wheel on my wagon?”’ And so on, ad infinitum. A Wizard With Toys Finally the old man reaches the stoop of his house and sits down. Then he begins taking things from his pockets—bits of wire and pieces of string, and a little bottle of glue, and knives and small punches and odds and ends—and begins to fix things. He glues a head on a doll; he performs amazing surgical operations that re- store absolutely broken china arms and legs; he does wonders with a broken fire-engine, and makes it rush furiously about on the sidewalk, hurrying to an imaginary fire. Then he takes a jack-knife and carves a boat or a man or something from a blozk of wood. And all the time the children watch him in rapt enchant- /; i As a boy, Jesse Armour Cran- dall was never so happy as when he was working in an odd corner of his father’s toy factory in Brooklyn. y / li | his toys long enough to invent and manufac- ture an invalid’s chair that gave the Presi- dent’s little daughter the first comfort she had had in many months. Mr. Crandall began making toys when he was three years old. He wanted a sort of ‘revolving wheel to play with and nobody had time to make him one. So he got a big knife and a piece of plank, and by dint of extreme labor and at the cost of several severe cuts— he bears to this day the sear on his forefinger where the knife slipped and almost amputated ©Press Illustrating Company he went to Ohio and taught toy- making to the inmates of one Later he con- ducted his own business in Brooklyn, where he still lives of the prisons. As a young man Even as you read this, your baby is perhaps staggering about the room safely encased in a baby-walker that Mr. Crandall invented, and your young son may be lassoing bronchos from the back of a plunging hobby- horse that also originated in the fertile brain of this toy-inventor. ‘Mr. Crandall is undoubtedly the oldest toy-maker in the United States. ‘He has taken out patents on more than one hundred and fifty inventions. Children all over the world owe him gratitude for their hobby-horses and shoofly horses, for.many types of fire- engines and wagons, for sand-molding machines, for picture blocks. that fit one within another, for go-carts, and for all sorts of wonderful things. Children of every nation under the shining sun, almost, have played with toys invented by Mr. Crandall, and children of royalty and of high officials of England and the United States have had fun with them, too. When the old toy-maker was a young toy- maker he made a giant hobby-horse, 45 the finger—he turned out a revolving wheel that would really re- volve. After that he made every toy he wanted, and invented a great many when he was a boy, that later, when he became old enough to realize their value, he patented. This fisrt toy was made in Wesley, Mass., where the Crandall family moved from Maine. Hundreds of Inventions The young inventor went to New York with his father when he was seven years old. There he worked in his father’s wagon factory, boring holes in hubs. This was rather hard, slow and tedious work, so young Crandall in- vented a machine to bore the holes, and with this machine he could there- after bore as many holes as he liked, depending upon the ratchets on the machine, instead of boring one .at a time with a brace and bit. This same ingenuity and skill he displayed later in developing hundreds of inventions, for he has invented many more machines and toys and things that he never patented. Grandpop’s life has been just about one toy after another.

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a aN TN IE ETE Te Sa rks, pepe cman wes ee er An a This man once saw a doctor use a headlight in removing tonsils, so he used a funnel with a lamp, leaving his hands free to work on the automobile engine, at night Making a car raise itself does not re- quire a magician if you have an en- gine - driven tire- pump and a pneu- matic jack. No The engine is ready and willing to work for you Popular Science Monthly Why Not Make Your Automobile Do It? 7 .@ He decided it would be a civil thing to do, to hand his guest a moist cigar from the door pocket. The door humidor keeps fresh a few choice smokes for occasions lifting, groaning or cursing results. The jack is on duty but is not shown in the picture An emery wheel attached to the headlight steadying bar and revolved by the crank- shaft. does away. with the tramp scissors-grinder. Any blademaybesharpenedbythe . motorist using this method He spirited. away his _wife’s sewing- machine motor and ground his car’s valves withit. The grinding speed was regulated by the foot-pedal as the speed of a sewing machine is regu- lated. Meanwhile the family sewing waited to be done (Left) Why not let the engine freeze the ice-cream? Attach the engine crankshaft to the handle of the freezer by a flexible shaft, with the car in low gear. You may save your energy while the car cheer- fully does the work (Right) A polishing cloth is fastened to the revolving shaft of the sewing-machine motor and the car is polish- ed in very short order

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July, 1920 What Becomes of Telephone Nickels After you drop them in the slot their adventures are varied and interesting When the collector has a dozen filled coin-boxes in his suit-case he goes to the place where a truck awaits him. He leaves his loaded suit-case in the truck and takes with him an empty one The original group of nickels is how surrounded by millions of other nickels in the same pre- dicament. In their dark cham- bers they are locked up in suit- cases and placed in a safe for the night, all secure from rescue Down into a dark, sealed chamber fall the nickels. When they have about given up hope of rescue, along comes a collector who re- moves the filled chamber and leaves an empty one instead j “ Empty coin-boxes are brought here to be sealed. Suddenly the gates are opened and the nickels tumble First they are locked. Then they are put into the out. They are shoved down a counting-machine, land sealing-machine, fastened with a strong lock and seal in a bag, and in the process are automatically counted July, 1920

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sncuenpuresemcanes ee eS T was the great Pasteur who taught | us that food decays because of the action of invisible, destruc- tive bacteria. Kill the bacteria and you prevent food from rotting. But how are they to be killed, or at least prevented from propagating? There are bacteria everywhere—billions and billions of them in the freshest lungful of air or mouthful of food—and they reproduce their own species with aston- ishing rapidity by the simple process of self-division. How is this growth to be checked? How are bacteria to be killed? When you answer these ques- tions correctly, you explain how food may be kept forever; you show how the high cost of living may be reduced; you abolish the criminal anomaly of fruit rotting on the ground while it brings a dollar a bushel in a city fifty miles away. Boiling Doesn't Always Kill Bacteria in Food Pasteur, of course, sug- gested ways of killing bacteria. That would almost follow from his mere discovery of the real cause of putrefaction. He decided that bacteria could be most effectively killed off by heat. That is the whole secret of the process of pas-— teurization. We know now why canners and housewives boil fruits and vegetables that are to be preserved. Not much was known about bacteria in Pasteur’s day— very little, for instance, about the tenacity with which they cling to life. It was discov- ered long after Pasteur made his revolutionary announce- ment that heat does not al- and nuts. broiled or to cheese when it is melted. Bacteria need warmth, moisture, and oxygen if they are to propagate. Cold storage preserves eggs, meats, and other foods because the destruc- tive bacteria are deprived of warmth. But they are not killed. As soon as the milk or the meats are taken out of a refrigerator they begin to putrefy. That is explained by the fact that foods cannot be refrigerated suddenly On the shelves are food products that range from fruit juices to solid vegetables, such as corn on the cob They were placed in their containers years ago; and yet, they are as fresh as the day when they were first preserved by the new process Popular Science Monthly Preserving Food Forever with Gas How a woman discovered..a way of asphyxiating the bacteria that cause decay and thus gave the world a marvelous process for keeping meat, milk, fruit, and all other food for centuries By Waldemar Kaempffert through and through. The outer sur- face is chilled first. Self-preservation is the first law of bacteria, as well as of human beings. If they can’t preserve themselves, they will at least try to preserve the species. Bacteria spore at once; in other words, they lay “‘eggs.’’ When a beef carcass is taken out of an icebox, the eggs develop as soon as they feel the first breath of warmth. Remember, they are num- bered, not by millions, but by trillions and trillions. Suffocating Bacteria to Preserve Food Between the molecules of every liquid is free oxygen. Whether a living thing be a whale, a man, or a bacillus, ‘ it must breathe oxygen. A man can be killed by depriv- ing him of his oxygen—not necessarily all of it, but enough of it. If it were possible to prevent a micro-organism from breathing oxygen, that micro- organism would die. It is true that modern bacteriolo- gists draw a distinction be- tween bacteria that do and do not live in air. All live in air. If some apparently do not, it is because their demand for oxygen is very minute. It may seem ridiculous to think of suffocating a living thing so small that you cannot see it. Yet that is the under- lying principle of the very re- markable food-preserving pro- cess discovered by Mrs. Helen C. M. Franks. She turns on the gas—not figuratively, but literally—and annihilates the bacteria of putrefaction by the trillion. What gases would kill you ways kill. It simply shocks— arrests development. The spore of the deadly anthrax germ still lives after five hours of persistent boiling. Many forms of bacteria resist the much lower heat applied in Pasteurization Moreover, the application of heat inevit- ably produces chemical and physiological changes in food. Everyone knows what hap- pens to an egg when it is boiled or to a steak when it is HY the well known properties of carbon dioxide have never before been applied in preserving fruits, milk must remain an inexovlicable mystery. It has remained for a woman to reveal the startling possibilities of the gas as a food preservative. Mrs. Franks, the discoverer of the process here described, has found it necessary to interpret micro- organic life in a way that will probably be objected to by most bacteriologists. At all events, the theory that she has evolved seems to be proved with startling conclusiveness by resulis.—EDITOR vegetables, meats, butter, and if you were to breathe them instead of oxygen? Half a dozen at once occur to you— marsh-gas (so deadly to min- ers), street-gas, nitrogen, car- bon dioxide, carbon monoxide, chlorine. While any deadly gas would undoubtedly kill bacteria if it were substituted for oxygen, the effect on the food in which the bacteria are contained must be considered. The gas must be sufficiently inert—that is, it must not combine chemically with the 48

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July, 1920 food to be preserved and thus destroy . its character. Nitrogen is such a gas. Less inert, but admirably adapted for the purpose, is carbonic-acid gas— carbon dioxide. There are very good reasons why carbon dioxide should asphyxiate food- destroying bacteria. In the first place, it is comes the final stage—recharging the container with carbon dioxide. Like the first step, the second must be scientifically carried out. Hewlett dis- covered that if a substance is sub- jected to a sufficient pressure of carbon dioxide, it will give up its oxygen and be kept in cold storage fortwo weeks, is kept sweet for two years in an atmos- phere of carbon dioxide. Milk has been kept for five years. Raw meat has been. kept for five years and fish for several months. How long can foods be thus preserved? As long as the atmosphere of carbon deadly. Lower a lighted candle into.a brewer’s vat filled with it and the flame is at once extin- guished. Lower a man into the same vat and his flame of life would also be extinguished. But there is’ another reason. dioxide is maintained, and that depends entirely on the character of the container. There is no reason why butter or fruit should not be kept for a century if materials can be found to with- stand the corrosion of time. It was discovered in When you breathe in fresh air (oxygen) you breathe out carbon diox- ide. Shut yourself up in a hermetically sealed room and you would be killed by your own car- bon dioxide as surely as if you turned on the gasin the room. So it is with a bacillus. It breathes in oxygen; like you, it breathes out carbon dioxide. Unless its supply of cxygen is renewed, it perishes. Carbon Dioxide Is Fatal When Breathed by Bacteria In the process of ‘‘frankerizing’’ foods, bacteria are killed by means of carbon dioxide. Assume that there may still be left a minute quantity of oxygen. The bacteria consume it. They substitute for it—what? Car- bon dioxide that they exhale. Their death is inevitable. In carrying out the process a law discovered by the English physicist Boyle is applied. At equal tempera- tures, Boyle said, two gases will mix perfectly—but only then. First of all, carbon dioxide is introduced into the food-container at the proper tem- perature. The air that surrounds the food—liquid or solid—is thus prop- erly diluted. Next, the container is exhausted by a vacuum pump. Now These jars contain eggs, sweet butter, and sliced bacon, which were preserved by means of carbon dioxide, and the replacement of the oxygen. They are perfectly fresh’ Healthy pigeons were infected with scrofula and neuritis and when near death were fed with Orange juice, which is rich in the vitamines necessary to sup- port life. served by this The juice had been vitamines absorb an equivalent volume of carbon dioxide. Since the oxygen must be re- moved, Hewlett’slaw is applied. The carbon dioxide simply takes the place of the minute quantity of oxygen left, and thus chokes the bacteria to death. But, it may be argued, if carbon dioxide kills men and bacteria when they breathe it, why should it not also kill. when it is eaten in food? It is a favorite trick, in college labora- tories, to eat small quantities of solid carbon dioxide snow. Gases act only on the blood that courses through the lungs; carbon dioxide must be breathed in order to kill. Treated by Mrs. Franks’ process, dairy products (milk, butter, and cream) can be transported in ordinary freight-cars without ice. Mrs. Franks’ one ambition has been to make dairy products cheaper, and above all to provide infants with pure milk at a price within the purse of the poorest family. Berry juices and pulp, which can be preservei only with much boiling and the aid of sugar, are kept for years after they have been frank- erized. Sweet butter, which cannot 49 preserved for eight months by the Franks process. Pigeons revived, and the experi- ment proved that in foods pre- process are not destroyed But the 1907 that what are called “vitamines’” must be present in food if we are to be nourished properly. Once it was supposed that proteins—by which we mean tissue-building substances, carbohydrates (starches and sugars), fats, water,and salts—were all-sufficient in food. Now we know that without vitamines they would do us little good. Professor Casimir Funk coined the name ‘‘vitamines.’’ No one has ever seen vitamines. No one knows much about their chemistry. All that scientists do know in a super- ficial way is that they are vitally necessary. the The Importance of Preserving the V itamines Vitamines in food must not be destroyed or removed at any cost. Pasteurization destroys the vitamines because heat must be applied. Think what this means to babies! An adult in any ordinary commu- nity is almost sure to eat enough vita- mines, because his diet is mixed. We suffer no injury if we use palatable substitutes for high-priced butter, or if we consume dry milk. But an infant subsists on milk alone for months and must depend on it for the necessary vitamines. Tomato pulp is in the first container, squash in the second, and corn on the cob in the third. Tomato pulp is notably difficult to preserve, but this has kept for three years

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Popular Science Monthly Ready-made Holes Are On ‘the Market Now ERETOFORE you have had screw holes made to order, but now you can buy them ready made. A _ pointed brass tube is threaded on the inside to re- ceive the screw. You hammer this tube into the wood securely, and its threaded interior serves as a screw hole. The wood can be used over and over again since the brass screw hole will never grow large through wear. How do you hammer these tubes into place without flattening the tops? A special steel screw comes with each sized tube, and it is screwed into the tube before This tiny mon- hammering is begun. When the tube is key burned his flush with the surface of the wood, the fingers, and the steel screw is removed and the regular hospital doctor wood or machine screw may be quickly is applying a screwed into place when you are ready soothing salve for it. This saves wear on the wood. Giving the parrot medicine for his cold at the ‘‘Mr. Dooley”’ bird hospital run by these two women Treating Patients at ‘‘Mr. Dooley’s”’ Hospital for Pets [s your bird sick? Then take him to Mr. Dooley. This “Mr. Dooley” runs one of the best bird and animal hospitals in existence. And who is he? It isn’t a he at all, but two women—Miss T. M. Jenkins and Miss A. F. Thompson—who are well skilled in the’ care of animals, and who do business under the firm name of ‘‘Mr. Dooley.’”’ Their hospital is a large one and is divided into wards after the fashion of hos- pitals for human beings. Charity patients receive just as good care there as pampered pets of the rich. As yet no one has complained of the treatment re- ceived, and the food gives perfect satisfaction toa wide 4 brass tube that is threaded inside, is hammered into the wood and acts variety of patients. as a screw hole for a wood or machine screw; it will never spread REMOVABLE SCREW ade HAMMER SCREW HOLE IN PLACE SEPARATE TOGETHER ' 1 ! : MATHINE SCREW SCREW Using X-Rays to Reveal Flaws in Sheets of Mica ‘Oped of mica, or isin-glass —— — examination. For that pur- are sent from the mines vee pose the General Electric to be made into sheets that Company has devised a special are used for insulation in apparatus. various electrical devices. In It consists of a cabinet in building commutators for di- which the operator views the rect current generators and tray of mica sheets as the rays motors thin sheets of mica passing through them bom- separate the copper parts and bard the fluorescent screen. prevent short-circuits which To protect the operator from would do great damage to the the injury of continuous ser- machines. Thousands of dol- vice the X-ray tube and ex- lars are thus saved by a thin posed parts are encased in piece of this material which has lead. There is an opening for a high resistance to electricity the rays which pass through action. But the sheet of the mica to reach the screen. mica must be free. from the Under the screen is a mirror smallest defect, such as bits tilted at an angle of 45 degrees of metal, or pin holes which and the operator sees the re- would permit the passage of flection of the screen. The the current. trays are automatically con- When the chips of mica are trolled and when being changed pressed into compact sheets it a lead shutter automatically is impossible to keep flaws moves to close the window from forming, and the only through which the rays would way to prevent the damage otherwise pass.and injure the when these defective sheets glass of the mirror. are used is to detect the flaws . . F Flaws in the mica appear inadvance. The most effect- z i se & ae black and sharply outlined, ive way to do this is to sub- The X-ray cabinet in which sheets of mica used in while small holes in the sheet ject the mica to an X-ray. electrical machinery, are examined to detect flaws can be readily detected. 50

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July, 1920 De eee ee steer oe ‘could co ve resultant floo Bae ah sdinceut coeabn . Se eeury Pumping Out the Water Faster than It Pours in When the ship is leaking badly, and is rapidly sinking after a collision with an iceberg, or other catastrophe at sea, the new centrifugal pump may save her and the lives of all on board. It is designed for use in just such emergencies, when water is rushing into the hold faster than it can be driven out with an ordinary pump and where other pumps may be rendered useless It has a working energy each minute equal to the combined effort of twenty-six horses, when operating in the depths of a large steamship, like the one pictured, where the water must be lifted to a height of 90 feet to be discharged. It is adaptable to difficulties. When it is impossible to lower it, a suction hose is passed down into the hold and the pump is operated on deck

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; HE government Bureau of Standards is a busy referee. It settles dis- putes between employer and employee; between producer and consumer, between repre- sentatives of various kinds of business, between importers and exporters, municipalities public-utility corpora- q tions, states and cities; ) and between nations, i when it is called upon to do so. The Bureau merely applies the yard-stick, the electroscope, or the thermometer, to adjust countless dif- ferences of opinion, more or less serious. It facilitates pre- cision in science, and assumes a high role of authority in standards | of meas urement, f standards of quality, and standards of me- chanical performance. What is the relative usefulness of gas of 565 British thermal units per cubic foot and gas of 22 candle- i power? One concerns i the heating power and 4 the other the illumi- nating power, and the answer from the Gas Engineering Section of the Bureau of Stand- ards decides the relation between the two. Granted that the appliances for light- ing or cooking are properly adjusted and the quality of the gas uniform, there should be enough heating and lighting value in the gas to make the gas useful for | ordinary purposes. New Standards are Investigated The huge demand for the by-products of oil far over- reaches the supply. From gas many of the same sub- stances can be taken, and the very great need for them in industry necessi- tates robbing the gas of much of its original value. The brilliant flame of the old-time fish-tail burner ae ogy ERNE REP ern r ene Sarnia permenant: sete a eee By S. R. Winters Here, under the spectroscope, the Bureau of Standards decides matters of color controversy. The quality of many substances figures prominently in their precise color, or the spectrum which they give. In the laboratory of the Color Section disputes on this question are settled by men skilled in this work The electrolysis of gas. and water pipes has been the cause of many disputes which have been carried to the courts. The Bureau of Standards has worked out plans to prevent this unnecessary damage and avert these controversies 52 Popular Science Monthly How Science Settles Disputes for the Business Man Solving manufacturing problems and adjusting economical differences in the Bureau of Standards wasted the rich benzol and volatile by-products. To conserve them today, it has been suggested that the heat- ing value as a standard be reduced to 528 British ther- mal units to a cubic foot, but the Bureau of Standards holds this a radical change of doubtful wisdom. Controversies have arisen as to the influ- ence of temperature in coke-making, upon the characteristics of the coke and _ the quantity and quality of gas produced. Heating Values of Gas Recently the Bureau of Standards conducted tests at the Sparrows Point Plant of the Bethlehem Steel Company, and it was found that gas pro- duced at high tem- peratures indicated greater value but less heat value than gas produced at lower temperatures, while the coke produced at low temperature is very inferior to other coke. The mak- ing of gas at high temperature tends to cause a greater de- composition of its less vola- tile material into gaseous elements, and results in a complete elimination of the mcre volatile substances. The slow cooking of coal at a lower temperature gives cff the lighter gases first, each increase in the degree of heat bringing forth the heavier constituents of the gas imprisoned in the coal. Application of intense heat at once changes the physical structure of the molecule, literally ‘‘cracking it’ into different combinations and producing different sub- stances, more valuable to industry perhaps, but pos- sessing less value as a gas to furnish heat for cooking, power, etc. Down in the coal region of the Cumberland fields

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July, 1920 of Maryland, the miners threatened to strike, charg- ing short-weight measure in their day’s output of coal. A representative from the Commercial Scales Section of the Bureau of Standards was detailed to test the mining scales. Inaccura- cies in the scales were not only detected, but the strike was averted, and the coal operators pleaded guilty to grand jury indictments of serious discrepancies in the mining scales. The master offender paid a penalty of $900. The Sugar Content of Molasses From Cuba the United States imports its ‘“‘black- strap’? molasses, the prod- uct being shipped by rail in tank-cars and vessels. Cuban exporters are under contracts to supply molasses with a certain sugar content. Disputes have arisen between the buyers and sellers as to the quality of molasses and whether the sugar content specified is present. The Polatimetry Section of the Bureau of Standards acted as referee. and made sixty-one analyses during 1919. The standard for the decisions is essentially that the value of molasses is predicated upon its thickness. An instrument, described as a picnometer, has been developed whereby entrapped air can be dis- placed and the density of molasses determined with scientific precision. A tide-motor corporation, claiming as its proverbial right the earth and a fence around it, was subjected to an exhaustive inves- tigation, the Bureau of Standards acting in response to a _ request from the United States Post Office Department. The claims of the com- pany were exploded and the use of the mails denied the promoters in advertising the instru- ment. The street railways of the United States are operated on the single overhead-trolley plan, with the electric current flowing into the rails through the car wheels after passing through the motor-cars. The current then retraces its steps to the generating station, after spreading through underground gas and A - y ——ii Railroad master scales throughout the country have been tested and serve as a standard for practically all railroad weighing in the United States cause of damage Supplementary protection to the ca- bles has achieved the results desired. Even international disputes and scientific discrepancies are not out- side the domain of adjustment by the Bureau of Standards. The Polari- metry Section has discarded the use of the time honored 100-degree sugar point established at the Sugar Insti- tute in Berlin. An error of more than one tenth of one per cent. has been revealed, the discovery meaning a saving of $70,000 annually in revenue to the Government, and to the pro- ducers perhaps untold millions of dollars. Important Work the Bureau Has Done The instruments at the various customs laboratories for the collection of revenue on imported sugars have been corrected in conformity with the newly accepted standard of value. Prior to this scientific adjustment, the fundamental constant in testing of sugars for purposes created by this elec- tric current. The Electrolysis Preven- tion Section of the Bureau of Standards has amicably avoided litigation between the public-utility corpo- ration and_ the city authorities of Wil- mington, Del., by having the street- railway company adopt the three-wire power distribution: system to avoid elec- trolysis troubles. of buying and selling throughout the world was the so-termed 100-degree point. This standard is de- termined by a pre- cision measurement using chemically pure sugar. While ascertain- ing the cause of certain anomalies in - the testing of sugars, the Bureau of Stand- ards discovered the discrepancy in a bus- iness in which the United States Gov- ernment collects $90,000,000 in rev- enue annually. of gas. a water-pipes. Theresult — 7 is endless litigation be- A block of optical glass taken from the melting-pot to be tested 53 A one tenth cubic foot bottle for accurately measuring the value This determines heating and lighting values The Government Bureau of Standards not only comes to the rescue of persons and communities in- volved in a dispute, but it takes the important role of benefactor in scien- tific matters. Difficult problems are attacked in the laboratories of the Bu- reau, and a general advancement of science in invention is the result. Not only are standards of weight, measure- ment, and quality established, but workable improvements in various lines of industry are advanced. From the testing of optical glass to that of carburetors, the Bureau occupies an important place of utility. ; Specialists cf repute in all lines of re- search areemployed in the]aboratories. They carefully study a problem and solve it if possible. They not only give to the country its standard yard, candle, and the standards of liquid measurement, but they apply these units in unraveling the problems.

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pane: sbemerprrastcabees EES CS OE 2 oe Te Popular Science Monthly ke : ) 3 = iz. 1, ninagil ee aia aad ise 1 tani. * + a0 with ok Blais wn Pe ame tye . Camping Out for Lack of a Home PEOPLE who find that moving day has arrived and they have . no place to move into, are driven to a quick make-shift for a house. If they are fortunate enough to own a lot, a temporary structure is sometimes hurriedly built; or a garage does duty until the home is constructed. An American family in Eng- land made a home of two cov- ered wagons that served for kitchen and livingroom. Safety First and Second in This Machine POWERFUL motor-operated side A Castle Built in Miniature " AN wants. but little here below,’”’ but he must not want it too long, too high, too wide, nor with too many frills on it. This is evidently the idea of the man who built a miniature castle for a house. feet of space. The entire building occupies no more than 20 by 20 It has an inner court 5 by 10 feet. The ‘“‘castle’’ cost less than $300 to construct. ering for electric switches. The metal press protected with a _ special safety device, the press being used to make another safety device, illustrates to what extent the “safety first’ idea is penetrating modern industry. Here a steel box is being stamped, the box being intended as a safety cov- box encloses the exposed current-bear- ing parts of the switch. The sheet of metal is perforated, stamped and shaped into the protecting switch-box. To operate the press, both hands are required so that neither may absent- mindedly beplaced in a position of danger. The Pen Clings to the Desk Magnet RE you always losing your pen? Hang it on a magnet. Then hang the magnet on your desk iamp. The outstanding feature of a magnet is its power to attract steel and iron. Since a penholder is usually made of light stuff it will dangle indefinitely at the end of its pen point when the pen point is in the clutches of a magnet. It will be there when you look for it. To loosen the pen, give it aslight tug and it will be released from the magnet none the worse for its hanging. . 54 VA Testing Drinks for the ‘‘Kick”’ HEN it was found that some of the 2.75 per cent beer had apparently developed a higher per cent of alcohol after having been stored, a rapid means of testing for the “kick”? was devised. It was also necessary to have a means of investi- gating the nature of near- beer which looked and tasted exactly like real beer. When a drink undergoes this test, a small meter on the side of the test-tube records the percentage of alcoho] it contains.

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July, 1920 © Kade! & Herbert Making Sharp Pictures through a Telescope ‘T HERE are several ways to focus a camera to obtain sharp pic- tures but one of the best is that which employs a_ telescope of small size. The lens of the telescope has the same focal distance as the lens of the camera so that when the photographer looks at the ground glass at the eye-end of the telescope he sees the same field of view as is shown on the ground glass of the camera. Racking the bellows of the camera in or out until the image appears sharp and distinct in the telescope makes the image sharp and clear on the ground glass, and on the film or plate when it is put into position. Wind-Shields Insure Warm Hands at High Speed POLICE Sergeant McCormick is the star motorcycle driver of Washing- ton and he escorts many distinguished visitors around the city. In the winter time he has found that in spite of his fur-lined gloves his hands are often numbed by the cutting wind. So he has fastened to the handle bars of his machine two round leather wind- shields. His hands no longer grow numb, and he continues to be the star driver. Other drivers on the police force have adopted the clever idea of Sergeant McCormick, and have wind-shields on their motorcycles. They eliminate a discomfort all motorcyclists know. The Oldest Clock in America Discovered in Atlanta ANTIQUARIANS recently discovered at the home of Mrs. P. H. Mell, in Atlanta, Georgia, what is believed to be the oldest clock in America. The plain- ness of the design and the use of cherry wood both indicate early construction as the first use of mahogany was in 1729. This pedigreed timekeeper tells the date, the status of the moon, and the re- lation of the hemispheres, as well as the hour, the minute, and the second. Paving an English Road with German Helmets “T‘EN miles south of London Bridge in the township of Croydon is the most remarkable road in the world. It is not walled-in with a long row of spikes upon which are gruesomely displayed the skulls of defeated enemies, in the manner one might find in uncivilized por- tions of the world. In- stead it. is paved with metal helmets of the van- quished foe. Tens of thousands of German helmets were taken there in the closing days of the war. These trophies have been put to useful service in making a good road where otherwise would be a stretch of mire almost im- passible. In almost every hel- met is the mark of battle.

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Use Coat-Hangers on Moving Day M OVING day, afoot, re- quired lugging many draw- ings, sheets of drawing paper and miscellaneous materials tied to a drawing board so wide that car- ried at the side under one arm, the fingers barely reached its lower edge. An ordinary coat hanger solved the problem of carrying it. The hanger was in- verted and its wire loop was hooked under the board. This Horse Eats No Oats HOBBY-HORSE must have been the favorite toy of Charles Johnson, of San Diego, California, for as soon as he reached the age of invention he patented a motor-driven horse on wheels. It is a full-sized metal one and its body is loaded with gears, chains, rods, and batteries. The horse keeps the steering apparatus in its head. It is guided by the bit which is connect- ed by rods to the front axle. slot machine. Customs Officers Look for Smugglers of the Air [N Europe the airplane has become such a common vehicle of travel that countries are guarding against smug- glers who might use the air highways. Airways would seem to be ideal for the smuggler. But landing-places are watched, and when a pilot descends the contents of his luggage are examined for contraband material. Customs officers greet the aviator at all landings. You Can Buy Your Stamps at the Mail-Box “Got a stamp?” That is one of the eternal questions. There are plenty of mail-boxes but comparatively few places where you can buy stamps. On Sundays there are almost none. But in Toronto, Canada, you can get your stamps at the mail-box. Just above the metal flap marked “letters” there is a Popular Science Monthly The Baby’s Carriage — with Variations ABY carriages in Germany get plenty of wear. In most cases they are bed and carriage combined. Behold the nursemaid above. When she came in from her walk she found that baby was fast asleep. And so she simply lifted out the body of the carriage, car- ried it indoors, and placed it gently on the floor. Baby con- tinued to sleep, undisturbed. An Elk Is His Trusty Steed UCK McKEE, is the rider, and he raised the elk himself, and broke him to the saddle. But Buck was once a Texas ranger, and breaking wild steeds is easy for him. The elk is not shod like horses, but wears sandals devised by his owner to pro- tect his feet on hard pavements; for Buck sometimes rides his elk into town, when, needless to say, he creates a sensation. Cor &? 6 we FF 1 Th =m ee PRU ll lk lk

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July, 1920 At the Bottom of the File APERS at the bottom of the file are hard to get at. Those above must all come off, if tearing is to be avoided. But not if you use the new type of spindle file here pictured. The spindle has a curving branch near the lower end off which the bottom paper may be slipped when the hollow spindle is lifted from its sup- port. The double end file is particularly useful in grocery and department stores where telephone orders are filed in the order of their receipt. Hanging by the Neck from an Airplane VEN when the day is totally devoid of wind and scarcely a breath of air stirs among the leaves, a gale blows where the airplane cuts its way. The hur- ricane churned up by the propellers as well as the resistance offered by the machine creates a violent wind which beats in changing directions across the persons in the fuselage if their position is exposed. When one realizes the strength of this artificial wind he can realize the difficult task of the acrobat who ventures to do ‘“‘stunts’’ on the wings of a moving airplane. Lieutenant Roscoe Turner was carried through the air hanging by a strap attached to the plane and to a support at his neck. If the engine had stopped there would not have been time for him to get back upon the wing of the airplane. His position would have been extremely perilous. Water, Water Everywhere ERMANY’S rivers havé, in many places, welled up and flooded the land. Even the much-loved Rhine has joined the ranks. At Coblenz everything that isn’t fast- ened down is floating. The American army trucks that were standing in the automobile park at the time of the flood are now almost completely hidden. Just their canvas tops may beseen. The over- flowing rivers of Central Europe have done nearly as much damage as the war. Sheets of Glue in a Glue Book LUE has always come in tubes or bottles, but now it comes in books that are very much like stamp books, with which you are familiar. The glue is smeared on thin sheets of paper that can be torn out of the book when they are needed. Both sides of each sheet are smeared. After all, a stamp book is half glue book and since it is a great success, the glue book should be one too. A strip when moistened on both sides will fasten two sheets of paper together, or may be used for mend- ing clothes. The busy housewife can do emergency mending quickly if she has a glue book.

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Popular Science Monthly

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SKETCH DIAGRAM OF TRANSMITTING SYSTEM " Signalling pulomerec Xe Local | Magnets encigised by cach efails Battery | Oscilldhon in A cote er ee lransgmitter ‘ ro TolS WIRELESS - CAB P iN - Be: $ -PESS Oscillating brass fy-mheel ollernalely rocked by magnets ond spiral shring | si LENCE CAR of THE AUTOMATIC RECEIVE RW» Leaf } and boint which Touch with

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ea, Magnifies ocal Relay, mhich operates << ee Signals eRe : a in Top inset diagram, A received Aulomalic Receiver - bal nom ; ss . (delails above) curren! fo be . se ag c a 4 sods ~ RB Pat, le : " The Wireless Alarm-Bell for Danger at Sea Just as a burglar-alarm summons help, so the new less cabin of each ship. The operator rushes to his wireless alarm-bell summons aid from ships within a seat, disconnects the special receiver, and waits for radius of a hundred miles. The wireless operator of word of the doomed ship’s position. the doomed ship presses a special key and a continuous The wireless operator who is sending out the distress call goes out automatically. call waits until he is sure that the alarm-bell has This key actuates a special receiver on all the ships sounded, and then he gives his position and the con- similarly equipped, and an alarm-bell rings in the wire- dition of the ship. The device is an automatic S. O.S.

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July, 1920 Ringing Alarm Bells Across Miles of Sea No longer need the wireless operator be constantly on watch at HE persistent clanging of a bell arouses the wireless operator from his sleep. In a moment he is at his instruments: “Gigantic answering. Ready for message.” The purring radio sends the response out in rapid repetition. There is a pause for answer. The alarm-bell stops clanging, and in its place comes: “Steamship Breton calling. Sink- ing. Lat. 35 138 North; Long. 75 17 West. Hurry!” A dash for the bridge, a quick con- sultation with the watch officer, and the Gigantic is off at full speed to the rescue. It will be in some such setting as this that a new wireless invention will prove itself, making it possible for ships at sea to eliminate the ex- pense of having a radio operator al- ways on watch, and yet keep an ever open radio ear to calls of distress. The device is in the nature of an attachment to existing types of ship radio equipment. Ships carrying it will have an automatic transmitting relay. Press a key, and it fires 180 dots a minute into the ether. The magnets of the relay ‘are controlled by a special contact-maker. This is formed by a brass flywheel within which is an iron bar. The wheel car- ries a brush for making contact with a stud, thus closing the battery cur- rent through the magnets of the trans- mitting relay. This contact is not normally open, the wheel being held in the proper position by a spiral spring. A pair of electromagnets act on the iron bar. If they are ener- gized, the wheel turns still further away from the position in which con- tact is made. While so turning the spring winds up. The current to these electromagnets is controlled by the brush on its flywheel. Now, suppose the wheel is turned by hand from its normal position until contact is made. Its electro- magnets energize; the iron bar arma- ture swings in the magnetic field, opening up the contact and winding up the spring. But opening the con- tact has de-energized the magnets. The spring now whirls the wheel back through its original position until con- tact is made again. And so the pro- cess repeats itself a number of times a second, depending on the inertia of the flywheel and the tension of the spring. Each time the wheel turns so as to make contact, the transmitting relay operates, and a dot is sent out by the regular radio equipment of the ship. Finding the Range in Miniature * P 50!” calls the officer. “Down 20!’ he shouts again. He is not gazing toward the open sea, but is merely looking down the deck toward a miniature target at which imaginary shots are being fired. Officers in charge of a battery must be trained in the difficult art of range- finding. The miniature target prac- tice helps to train the officer and make his work far more accurate when the actual firing at targets at sea is conducted under his charge. At the end of a clear stretch of the deck is placed an exact miniature repro- duction of the large targets used at sea. The officer who is to be taught an accurate judgment of dis- tance looks toward the tar- get through marine glasses. He lies flat upon the deck to bring his eyes in line with the target. The in- structor who is to check the results of the observer stands near the target and places before or behind it a roll or wad of cloth which is shaped in the correct proportion to represent a “‘splash’ caused by the falling shell. Inches represent so many yards, and if the splash is between the observer and the target he will call “Up,” and state the estimated number of yards short of the mark. If the splash is back of the target he calls “Down” and gives the number of yards beyond. sea Instead, however, of starting the contact-maker by hand, a short-cir- cuit key is provided, which allows the coils to energize. Pressing the key causes the spring to wind up; releasing the key allows the contact-maker to operate as an automatic transmitter. Such was the operation on the ship whose distress call the Gigantic had picked up. On the Gigantic the oper- ator, before going to sleep, had left his receiving circuit in operating condi- tion and had thrown a switch that connected a three-stage amplifier in place of the head receivers. This amplifier feeds into an automatic receiver which is built on the same principle as the transmitting contact- maker. A dot energizes its magnets, turning a light flywheel until contact is made by its brush. During the interval following the dot, the spring whirls the wheel back, ready again for the next dot. Each time the brush makes a contact, it closes the same transmitting relay as is used in sending distress sig- nals. But this relay is now hooked up to close the circuit of an alarm bell. The receiving mechanism must be — adjusted to have the same time of or- cillation for its flywheel as the trans- mitter of a ship from which it receives. 7 ~ The officer being trained in observing the results of fir- ing the big 14-inch guns. Miniature targets are ob- served through the glasses, the observer lying flat upon the deck to make observations The targets are placed far down the deck from the observer. An officer stand- ing near by checks the range as it is called by the observer, the shots being marked by an aftificial splash made of cloth thrown up as they fall

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New Jobs for Old Photographic Plates After you have washed off the emulsion they are ready to start Popular Science Monhtly Next time you have your picture taken, ask for the plate. Wash it off and you will have just the right-sized piece of glass to frame for many purposes Would you like to turn Glass table tops are now in vogue, but they’re costly. How would you like to get one for ten cents? All you need is some'cement with a few photographic plates your back porch into a sun parlor like this one? Build the framework and then fill up the gaps with photographic plates. A small conservatory could be built of old plates and the necessary framework of wood to support the walls and roof If you drive toward the sun, its glare will blind you. One motorist fastened a strip of green celluloid to an old photographic plate and mounted it on a stand in front of him, to soften the glare in his eyes Sometimes strawberries are pre- served by exposure to the sun. While exposed they must be cov- ered over with glass. Use old photographic plates to cover them Should you take a picture of a beau- tiful scene have a positive made of the negative, on glass to hang in the win- dow. The old negative protects it. The two plates are framed together 60 You can let in the fresh air but keep out drafts with a glass screen like this, made of two old photographic plates held together with cement. Transparent cement should be used Dannlar Seienre Monthly oP? 2. Se eee Oe ee eC lS cot hh

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July, 1920 Keeping Up with the March of Science Facts for the man who wants to know - Solving the Paper Shortage HEN cotton is ginned to remove the seed, linters are obtained—seventy- five pounds of linters to a ton of seed. Ger- many used to buy from us half a million bales of linters for the making of explosives. Our own uses for the material were more peaceful—stuffing mattresses, cushions, horse-collars, and upholstery. When the war came, we also had to use linters for making explosives. The signing of the armistice found us with 12,000,000 bales of linters on our hands. 000,000. The answer is supplied by the Bureau of Standards and the Forest Prod- ucts Laboratory. ‘‘Make paper,” it reads. The Bureau of Standards admits that the first experiments yielded only a mediocre paper, but new developments indicate that linters can be used in the making of maga- zine and book papers. We fancy that we hear cheers from the magazine publishers. On Shoes and Feet ROHIBITIONISTS and other re- formers have worried much about our morals, but very little about our bodies. We direct their gaze to their own feet. Alcohol is bad for the mind and soul. The shoes of to-day are bad for the feet and the body. Physiologists have tried to make men and women wear sensible boots, but no one pays any attention to them except a few health “cranks.” Ninety-five per cent of the women of this country have foot trouble in some form because of high-heeled shoes. Efficiency is reduced from ten to fifty per cent, as a consequence, accord- ing to the American Museum of Safety. What is more, correct walking is almost a lost art. After the world is dry and tobaccoless, perhaps the Constitution will be extended to include an amendment covering the case. The Slump in Mice URING the war thousands of mice were caught and bought for medical experimentation. The breeding of mice became a profitable industry. Now that the war is over, the breeders are “‘long’”’ on mice and are carrying large stocks. The seientists who are administering the George Crocker Special Research Fund, taking pity on the breeders, are trying to ship: mice to the Imperial University of Tokio—as if Japan didn’t probably have enough mice of its own. Wanted: A Map VERYBODY — supposes that’ the United States has been thoroughly mapped. The truth is that only forty-two and one-half per cent of the area has been What was to be done with them? . The financial loss involved was $280,- ~ surveyed. That is why a map-making conference was recently held in Washing- ton to discuss the Geological Survey’s topographic program. It will cost $40,500,000 to complete the map of the United States and to make certain necessary resurveys and revisions. If the Survey’s program is carried out we may have a scientifically prepared map by 1932. Without accurate maps it is a very difficult matter to lay out and establish highway systems. Living Five Hundred Years HE thyroid gland seems to be a kind of switch that controls both the rate and form of animal growth. An idiot (cretin) at the age of twenty years may be no larger than a child of six and possess the mental powers of a baby. Feed him with thyroid extract and he becomes a happy, healthy child. Tadpoles fed on thyroid turn into frogs long before their time. Remove the thyroid from the tadpole and it refuses to become a frog at all, but grows and grows until it becomes three times as big as an ordinary tadpole. The axolotl, a fish that is a staple of diet in Mexico City, and that normally grows up into an undeveloped tadpole-like form, with gills and with a fin to its tail, can be turned by thyroid at will into a salamander-like creature, living on air and breathing with lungs. If we only knew more about the thyroid we might be able so to control growth that we could live five hundred years. Life’s processes and the thyroid gland are inex- tricably bound together. Filtering with Spun Glass FINE, sharp sand in oil from the Gulf Coast region cuts barrels and fills tubing. Recently experiments have been made that prove that spun glass is able to filter out the finest particles. What is more, tiny water globules are increased to such a size that it becomes easy to get the water out of the oil. No More ‘‘Listening In’’ [t is easy to “‘listen in’”’ on the telephone. Indeed, “listening in’ is a favorite pastime in rural districts. Captain Poir- son, a French army engineer, has overcome the telephone’s ‘one drawback by deform- ing the electric pulsations that travel over a wire and restoring them to their correct form at the receiving end. Listen in as much as you like, the conversation is un- intelligible. Deformation of the message was easier than reforming. - Excellent results have been obtained with Captain Poirson’s apparatus over the Paris-Bordeaux line, which is about one hundred miles long. 61 Folding Wings for Airplanes W HEN a flying-machine that has crossed the Channel from England to France lands at Le Bourget, formalities follow that recall the endless. ceremonies of entering a harbor by steamship. There are signals from lighthouses, warnings from weather bureaus, customs officers who cross-examine passengers, toll-collecting, and the payment of harbor dues. The big Handley-Pages, which can fold their wings back in a very birdlike way, have at least one advantage over their smaller competitors. Harbor dues are assessed on the basis of the number of square meters occupied. What does the big Handley-Page do? It simply folds back its wings and pays the minimum! What Became of the Bison (5 20RGE CATLIN, an authority on — Indian life in the middle of the last century, stated that in the 1830s from 150,000 to 200,000 buffalo robes were marketed annually, which meant a slaughter of 2,000,000 or 3,000,000 bison annually. The death-knell of the bison was sounded when the Union Pacific Railroad was under construction. The road made marketing of the robes easier and divided the northern and southern herds. By 1875 the southern herd, consisting of at least 3,000,000 animals, had been exter- minated. By 1889 the northern herd, too, was practically extinct, its actual numbers being placed by Dr. Hornaday at 635 animals. Dr. C. Gordon Hewitt, of the Ameri- can Museum, calls this ‘“‘the most strik- ing and appalling example of the fate of an animal existing in apparently inex- haustible numbers, when left exposed to unrestricted slaughter.”’ Left Over from the War LIKE most European cities, Paris mounted numbers of sirens during the war in order to sound warning of im- pending airplane raids. What is to be- come of the sirens, now that the war is over? The officials of Paris are thinking of distributing them among French villages, where they are to serve as fire-alarms. American papers please copy. % The Elephant’s Future HE elephant is an animal that is extinct, in a sense, and doesn’t know it. He belongs to a past geological age. A knight in clanking armor on Main Street is no more of an anachronism. If Africa continues to develop as rap- idly as it has been doing, its elephants will soon be reduced to the status of curiosi- ties, like the American Bison, with the

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a — - Seal aee enn a tienes ane oS i a | | | | | difference that the bison can be more easily kept in captivity than the elephant. It has become necessary to destroy a herd of about two hundred elephants in the Addo Bush Forest Reserve ‘South Africa), a herd that was the last remnant of a variety thet once roamed all over southern Africa. The immediate cause of this was the opening of Addo Bush to agriculture by irrigation projects. Since the elephants would not behave, and since their confine- ment would have entailed the building of a thirteen-mile fence at a cost of $109,000 and the provision of a water supply, they had to go. About a Roomful of Air NOVELISTS and poets use the air as . a symbol of lightness. ‘“‘As light as air,” ‘‘as thin as air’’—how many times we have read the phrases! When next we meet a novelist, we’ll ask him whether he could carry a roomful of air if it were compressed into a dress-suit case. Of course he will boast of his ability to doso. And then we will hold this novelist uv to scorn and snap our fingers under ~ his nose and say, ““That for your knowl- edge!” Air weighs seventy-five pounds a thou- sand cubic feet. A room that measures twenty feet long by ten feet wide by twelve feet high contains one hundred and eighty pounds of air. A New Use for Ticket-Holders HOSE flexible commutation-ticket holders with celluloid windows flashed every morning and evening by suburbanites, have an industrial use. The ‘‘job ticket,” which travels with a piece of work through a factory, and which constitutes a record of machine operations, is one mass of oily smears when it reaches the end of its journeys, despite the ‘‘“Keep Clean” notice printed on its face. Now the job ticket travels in a holder with a celluloid window and arrives at the accounting office with a reasonably clean face. Try it in your factory. In Praise of the Peanut ‘THE peanut used to be regarded merely as a trimming for the circus. Since the war it has become a valuable food product. Salad oils, oleomargerine, soap, and cooking compounds are now made of peanuts. One company timidly experimented with a carload of peanuts ten years ago; now it consumes annually three hundred carloads. Last year twelve Southern States planted peanuts on 1,251,000 acres and grew a crop worth $80,000,000. A peanut-grower used to throw up his hat with joy when he received a dollar a bushel; now he hems and haws when $2.50 is offered for a choice crop. The Department of Agriculture is now making scientific studies to discover the best varieties of peanuts for particular pur- poses and to develop the best marketing systems. The Carnage of Peace F the 2,000,000 Americans who went to France to fight, 56,227 were killed or died of their wounds. More than 200,000 were wounded. In the same period of nineteen months in peaceful America 126,654 men, women, and children were killed, and more than 2,000,000 were so seriously injured by accident that they lost more than a month’s time or were permanently disabled. Where is the man who started the safety first movement? Air Studies of the Ocean R. VOLMAT, a French scientist, recently exhibited in Paris a series of photographs taken from a seaplane, which prove that in order to find out how deep the ocean is, you have but to fly up into the air. Depths can be gaged by studying the photographed tints of the water. Whether the bottom is sandy, muddy, rocky, or granitic is easily deter- mined. From which this French scientist con- cludes that aerial photography may be employed as an aid to navigation by revealing the character of the waters that fringe a country’s coasts. Mixing Paint by Air M?°st factories use whole pools of paint. Kept settles. It must be stirred from time to time, generally by sheer muscular effort. In one Western factory a resourceful workman hit on the plan of mixing paint by air. The paint was kept in barrels, and in each barrel there was a wooden paddle. By connecting a pneumatic reaming tool with the paddle-shaft and turning on the air, the paint was thoroughly churned up. Keeping Fruit Fresh a Year PRESERVING fruits without sugar, alcohol, or heat? It is hard to be- lieve. Yet the food ministry of France announces a process for performing the seemingly impossible. Professor Gabriel Bertrand is the dis- coverer. He claims that fruits can be preserved by washing them thoroughly and sealing them hermetically in a jar filled with sterile water. There must be no air in the jar or the water. Fermentation is sure to set up if air is present. Delicate fruits, such as strawberries and apricots, have been kept for a year by Professor Bertrand. Bad for Rats ULPHITE liquor is the bane of the paper-maker. What shall be done with it? Municipalities object to having it turned into streams. It kills fish and pollutes the water. The chemists have been making suggestions about sulphite liquor for years, but it seems to be cheaper to let it run off than to carry them out. 62 in a tank, paint- _ Popular Science Monthly Alcohol is one of the products that can be obtained. More curious is the fact that the liquor contains substances that act as a protection against rats. Added to artificial stone made from marble cement, it pro- duces a product of great strength. Clayey soil is not much good for building, because it does not bind well with lime mortars; but when milk of lime is mixed with the liquor and the loam or clay is stirred in, the result is a material out of which strong bricks can be made. Gassing the Criminal A LONE negro, barricaded in a Balti- more cellar, recently held at bay two hundred policemen for three hours. Dr. Robert W. Wood, of Johns Hopkins Uni- versity, promptly comes forward with the suggestion that tear gas could be used with good effect in such situations. “‘Such a gas,”’ he assures us, ‘‘could have been projected into the cellar by the simple act of throwing” (presumably in a hand grenade). The man behind the barricade would be temporarily blinded and his shooting aim destroyed. A pre- liminary dose of sneezing gas would make him reveal his location. Read Your Own Meter UR faith in humanity, somewhat battered after the events of the Peace Conference, has been partially restored by ' the news that in the far West some of the. power companies will let you read your meter, and take your word for it that the reading is truthful. A post-card is left at your house by the trusting company. You return it with your reading, whereupon you receive a bill, which you pay by check. The practice has been adopted chiefly in the rural districts. The companies maintain that the problem of accounting is simplified, and that there are few complaints of overcharges. To make absolutely sure that the Muen- chausen in us does not assert himself the company sends out a meter-reader in the spring, just at the time of year when the imagination is most riotous, Why Timber Roofs Rot "THE timber roofs of weaving-sheds, paper-mills, and finishing works have been rotting away alarmingly. To find out why, F. J. Hoxie, who seems to be an inquiring factory inspector, made a special study that is illuminating. He finds that moist air gives the wood-rotting fungi their chance. Sometimes as much as fifty tons of water is evaporated in a day in a textile-finishing mill. Mr. Hoxie discovered that wherever the wood is dried by steam-pipes or other means the fungi have no chance, but that where the steam-pipe ends the wood shows signs of decay. The remedy is obvious. Prevent the escape of the heat, says Mr. Hoxie. In- crease the insulation; use steam-pipe covering for drain-pipes and heavy plank for ventilator-openings; stop the moisture from penetrating the roof plank.

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July, 1920 Perforations are made in the top of the bag and through them the cord is run. For- merly the holes were made one by one, but now there is a machine that punches a number of bags at one stroke. Thousands a day are punched Each bag must have its lock. This is the room in which the locks are made. They are carefully tested before being placed on the bags Mail Bags in the Making They’re fashioned so stoutly so that letters can’t escape After the cloth is cut, the seams are made and the topis hemmed. The machine that does the seaming is capable of handling as many as three hundred sacks in sixteen. hours This is the ‘new lock-cord fastener now used on mail bags. After the lock has been -opened, the clasp can be released by slight pressure on what is known as a “dog.” This lock-cord fastener was invented by a mechanic in the mail equipment shops where unused bags are kept When a bag is worn out it is sent to the repair shop. If it is not too far gone it is repaired. Condemned bags are ripped apart

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Fo an ene er ea nett Span ttn a —_—— 7 oy menial lentes etl * aiene F you do not think that grain-dust is an explosive, or rather a com- bustible mixture, just come and wit- ness the demonstration given by the United States Department of Agri- culture. A miniature and portable grain elevator has been constructed to illustrate how grain-dust explosions can take place in elevators where dust has been al'owed to accumulate. By means of a hand bellows a table- spoonful of dust is blown into the little elevator, in one end of which a small lamp is burning. The dust cloud is ignited by this flame and the finely divided, combus- tible particles flare up instantly, and with the expansion of heated aii the explosion takes place. In the miniature elevator the heavy paper coverin: over the top where the force of the explosion was started, is blown off. Without this escape valve the elevator would fare somewhat in the manner of the large ele- vators which have their roofs and walls demol- ished by the ignition of grain-dust inside. Occasionally in the ex- periments charges of dust slightly too large have been used, and the galvanized iron miniature has burst. Bolts ex- tending from side to side have been put in to prevent recurrence of such a disaster. The whole experiment is proving an effective means of teaching the men in the grain-handling plants the dan- ger of allowing dust to accumulate. The extent of damage that may result from dust explosions is shown by the serious explosions which occurred in a period of only four months, here and in Canada. Five explosions caused the deaths of seventy people. Popular Science Monthly | _ Grain-Dust Explosive ? Watch It Flare = A small galvanized iron grain elevator serves as a model to experiment with com- bustible mixtures of grain- dust and air. Watch the sheet of paper fastened over the top of the structure There, she’s off! The table- spoonful of grain-dust blown with a pair of bellows into the elevator has been ignited by the lamp, and its particles have flared into flame. The experiment is useful in teach- ing the men in grain-handling plants the danger of allow- ing grain-dust to accumulate This Telescope Is Built to Discover Comets OMETS appear suddenly out of the obscure depths of the night and the observer who first catches sight of a new comet is quick to tele- graph the news and claim the discov- ery. There are astronomers who on every clear night search the heavens patiently, hoping to add one of these erratic wanderers to their list of discoveries. To at- tempt this search through an ordi- nary telescope tires the eyes be- cause of the strained position of the head when using arefractor. Com- fort is an important consideration in careful telescopic observation. With tired eyes and a strained neck the observer might not recognize the faint wisp of light which often is all that characterizes a newly arrived visitor. “Sweeping for comets” is made convenient by a telescope so ar- ranged that the observer can look through th2 eyepiece without changing the position of his head. As though peeping through a little circular window he sees the starry fields of the sky. A slight motion of the telescope brings other re- gions into view. The motion can be easily controlled by turning a wheel, much in the manner of guiding an automobile or piloting an airplane. In the trip through the starry depths of night, wandering among stars too faint to be caught with the naked eye, Dr. Metcalf looks for comets with this convenient ‘‘comet-seéker.”” He can easily turn it in the direction desired 64 the astronomer glimpses a mere speck of luminosity. He studies it care- fully. Then he looks at his catalogue of nebulae to make sure that this is not one of those evasive bodies remote in the distance of space. Not finding it to be a nebula, the observer reads the position angles of the stranger, then he watches it patient!y for thirty minutes or sev- eral hours. Comets that are re- mote from the earth do not appear to move very rapidly. The slight- est indication of change of position with relation to the nearby stars wi!l at once proclaim the body to be either a comet or an asteroid. If it is decidedly nebulous in appear- ance, the chances are that it is a comet. Rev. Joel H. Metcalf, of Win- chester, Mass., has devoted much time to the pursuit of astronomy. He has successfully attempted the difficult task of making several re- fracting telescopes. The 16-inch doublet now used.at Harvard Col- lege is an example of his skill as an amateur telescope maker. During a vacation at Camp Idlewild, South Hero, Vermont, Dr. Metcalf dis- covered two comets in one week.

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a. Mp re July, 1920 What Is There in Telepathy? Let us consider the evidence for thought transference OU do not believe in telepathy? These lines that you are reading -—I have written them. You understand their meaning. Then, it seems, I have been successful in trans- mitting thought from my mind to yours, have I not? Ah, you say, that is different. Tel- epathy means direct thought transfer- ence, without words actually spoken or written. But is that so different? You think that words are the essential element in actual, bona fide thought communi- cation. Think again. Are words really so fundamental, or is there something else more basic involved? If it really is just a matter of words, then, for example, what thoughts do these words convey to your mind: ‘Na varina cudyaty antaralma’’? Gibberish? No; Sanskrit for: ‘‘The conscience can not be washed clean with water.” You say, ‘“‘Oh, well, of course, I do not understand San- skrit.”’ Very well. Words alone are not sufficient. There must be something else, something more essential: there must be wnderstanding. Or, to put it a little differ- ently, your mind must. be attuned to the language and the thought of the speaker. You must have learned the language, and if the thought is presented in writing, you . must also have learned to read.’ And what is this proc- ess of learning but the attuning of your mind to certain stimuli, so that it responds to them as the strings of a musical instrument respond to certain notes? After all, the only thing that words can do is to create in us a frame of mind more or less closely similar to tha: of the speaker or writer who has framed them. As for the question how words accomplish this, if you can shed any light on this, you are wiser than most men. And as long as we are in comp!ete ignorance as to how words do this, what logical grounds have we for the contention that the same thing cannot be accomplished with- out words? Accepting Things on Faith Perhaps your answer is: ‘Well, I may not be able to explain trans- mission by words any more than By A. J. Lorraine thought transference without words; ° but, anyway, I am familiar with the first, and havenever observed the latter. Card-guessing experiments do not prove telepathy. The guesser may be unconsciously guided by an invol- untary, imperceptible muscular impulse from the person knowing the correct card, whose hand he holds When I do, I shall begin to believe it.” Have you ever seem the rings of Saturn? If not, do yew doubt their existence? No? Then you are relying on the evidence of others. Now listen to the evidence of some who tell us their experiences of thought transfer- ence without speech or any of the ordinary channels of communication. Mrs. Green’s Strange Dream Thought transference may be spon- taneous, or it may be experimentally provoked. Spontaneous thought trans- ference is no doubt usually more dra- matic; on the other hand, experi- mental thought transference is more convincing as evidence, since the con- ditions of manifestation can be accur- ately controlled. Examples of spontaneous thought transference are innumerable. Many persons have experienced it in theirown 65 lives, and it is safe to say that every adult has heard, on testimony deemed trustworthy, evidence of cases gmong his near relatives and friends. As an illustration I may quote the following example given by Dr. Joire, Profes- sor at the Psycho-Physiological In- stitute of France. The account of the occurrence is given in the words of Mrs. Green herself, who experienced it. She writes: I saw two respectably dressed women driving a vehicle like a mineral-water cart. Their horse stopped at a pool to drink; but as there was no footing he lost his balance, and in trying to recover he plunged right in. With the shock the two women stood up and shouted for help, and their hats rose off their heads, and as all were going down I turned away crying and saying, ‘“‘Was there none at all to help them?” Upon which I awoke, and my husband asked me what was the matter. I re- lated the dream to him and he asked me if I knew the women. I said I did not, and that I thought I had never seen either of them. The following third month I got a letter and a newspaper from my brother in Australia, letting me know the sad trouble which had befallen him in the loss, by drowning, of his daughter and her companion. My nieee was born in Australia and I mever saw her. The account of the acci- dent given in the newspaper that accompanied the letter tallied in every detail with the scene of the dream. Picking the Right Card Thought transference of this kind is commonly connected with scenes of distress, and often of sudden death. The conditions for transmitting im- pressions from one person to another in this way are therefore, as a rule, not within the control of the persons com- municating. There are, however, on record, some instances in which a per- son has deliberately willed to appear to others, and has succeeded in his pur- pose. A case of this kind is quoted by F.W.H. Myersin his “‘Phantasms ofthe Living.”’ The apparition was seen by two persons at the same time, so that ‘ the phenomenon would seem to be not wholly subjective. Of the more definitely experimental controlled thought transference, the

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first example that comes to mind—not a good example, as we shall see presently— is that of the well known parlor game of guessing cards and performing sim- ilar tricks by ‘thought transference.”” A number of cards are laid out on the table. The company selects one card for the ex- periment. The person who is to guess it is out of the room. He is then brought in (blindfolded, if desired; this makes no difference in the results, though it may be helpful to him in keep- ing his attention from being dis- tracted). He is placed where his hand can reach the card, and some person acquainted with the choice made by the company takes hold of one of his hands, leaving the other free to pick the card. The agent (the person knowing the card) concentrates his thoughts on the card selected. The percipient (the person who is to pick the card) makes his mind a blank, as far as possible. When he feels that the right moment has come, he puts out his hand and picks up a card. Not all persons are adapted to this trick, but with a suitable pair a considerable number of successes can be scored, although both agent and percipient are quite unconscious of having com- municated by any kind of signals. Scientifically Conducted Experiments Experiments of this kind, in which - there is actual contact between agent and percipient, are quite inconclusive, and cannot be regarded as in any way evidential of direct. thought transfer- ence without intervention of recog- nized physical agencies. For it has been conclusively shown by psychol- ogists that a person may be guided in his selection by stimuli too slight to rise to his consciousness, but neverthe- less capable of influencing his actions. The percipient can thus receive hints from the agent—by involuntary mus- cular pressure or twitchings of the hand—without either of them being in the least aware of the fact. But there are many examples on record of thought transference without contact. The stage performances of professionals in this direction we may leave entirely out of account, since it is well known that most, if not all, of these depend on an ingenious code of signals cleverly disguised in the man- ner of putting the question, ‘“What is this I hold in my hand? The num- ber?” etc. If no words are spoken there is still the possibility of other modes of signaling, of collusion, and of trickery of all kinds. An entirely different order of evi- dence comes from experiments con- ducted along scientific lines by com- write o7 The straight line and curve are drawn by the agent. cipient draws a straight line and curve, reversing positions. is significant, sometimes ally” in reversed handwriting The per- This mediums *‘automatic- since petent and trustworthy persons. Some of the results so obtained are most striking, and, at first sight at any rate, conclusive. So, for example, the agent holds a pad of paper. on which he draws a simple diagram. The per- cipient, so placed that it is impossible Mr. Guthrie drew a picture of a fish. Miss Edwards said, “‘Are you thinking of the bottom of the sea, with shells and fishes? Is it a snail or a fish?”’ drew the above reproduction - Popular Science Monthly for him to see the drawing, presently sketches on an- other pad the impression received telepathically from the agent. In a con- siderable number of cases there is found to be a more or less marked resemblance, sometimes practical iden- tity, between the two draw- ings, as the reader can see for himself in the illustra- tions reproduced from an actual series of experi- ments. . At first sight the evi- dence of such a series of experiments, in which suc- cesses sometimes approach to close upon a hundred per cent, seems most convincing. But two human beings have taken part in the experiment, two members of the same biological species. Weare all built very much on the same plan. There is the old joke about the She then lew a LONE OR ge a SERA arttgatecatioes: — pa a Vili EG whose work he had never seen. ee a This is a sketch made by Thompson “when he felt like Gifford,” Below is one of Gifford’s paintings abate Frederick L. Thompson, a_ goldsmith, followed an impulse to paint. He said he felt like Gifford, a dead painter. Visiting 66 Gifford’s former studio he found a painting by Gifford duplicating one of his own. The two pictures are here shown oe soe om: |) oe

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July, 1920 spiral staircase. Ask anyone who has not already been a victim to this harm- less joke: ‘‘What is a spiral staircase?’ In nine cases out of ten he will motion with his hand, and say: ‘‘It is a stair- case that winds this way,”’ or words to that effect. Under similar circum- stances we all do very much the same thing. So, if two people draw a few simple diagrams at random, the chances are that a good propor- ~ tion of them will be very similar. It looks like thought transfer- ence, but it is merely the similar working of two similarly con- structed machines—so the skep- ties say. Lieutenant-Colonel Le M. Taylor, however, has shown, to his own satisfaction at any rate, that the successes obtained far outnumber what might be expected on Professor Sedgwick Minot’s theory of chance combinations due to similarity in the human make- up. Chance or Telepathy? Can coincidences account for strange cases of telepathy? In the case of Mrs. Green’s dream of the drowning of her niece, for example, was it purely chance that this should have occurred just at the time of the accident? Improbable to the point of being impossible, you will say. But do not forget that highly improbable things are happen- ing every day. A notable ex- ample of this formed the sub- ject of a law-suit some years ago. An English magazine called the Rocket had offered a prize of $5,000 to the person who should guess correctly the number of male and female births, and the number of deaths in London during the week ending December 11, 1897. A butcher of the name of John Henry Hall made 252 guesses, including one that turned out to be correct, as follows: Births, male, 1,244; female, 1,245; deaths, 1,866. (Incidentally, he won his suit.) It has been estimated that the chances of making a correct guess in 252, in this case, was one in 1,740,000. Yet the event occurred. Many other examples of equally unlikely things happening are on record. inal err" Miss Birchall drew a corkscrew curve. Miss Ralph looked at them and’ said she seemed to see a lot of moving rings ° July, 1920 It must, indeed, be admitted that most extraordinary coincidences do happen, and are even comparatively frequent. Naturally, if such a co- incidence happens to relate to an event of great personal significance and strong emotional anneal to us, such as the death of a near relative, the occur- rence remains indelibly fixed in our memory, while less striking examples, The agent draws simple sketches. The percipient, who can- not see them, sketches the impressions telepathically received. To the left in the above picture are the agent’s orig- to the right, those of the percipient drawings; equally common, but without personal appeal, quickly fade from our recollec- tion. This may lead to an impression that there is some causal connection between a dream, or a presentiment, and some event to which it appears to relate; when, in point of fact, there is nothing but a coincidence involved. The volume of evidence of remarkable occurrences of this character that has been collected, however, makes this explanation appear decidedly strained. The Thompson-Gifford Paintings Inasmuch as telepathy does not appear to depend on the ordinary physical action of our senses, some investigators of psychic phenomena (among them Sir Oliver Lodge and Dr. Hyslop), have held that it is a mode of support of this thesis, one of the most remarkable instances is the Thompson- Gifford case. A certain Frederic L. Thompson, a goldsmith, was suddenly and inex- plicably seized, one summer, with an impulse to sketch and paint pictures. He was an uneducated man, with no art training. As an engraver he showed, however, a certain native talent for sketching. With this impulse to sketch came a disinclination, a nausea for his regular work, which ulti- mately rose to such a pitch that he became unfitted to attend to his business. He had had a very casual acquaintance—two or three meetings and only a few words spoken—with Robert Swain Gifford, the artist, some years before. Now, there were strange things about Thomp- son’s painting. He used to say that when he was sketching he felt that he was Gifford. He would remark to his wife, ‘‘Gif- ford wants to sketch.” In point of fact, Gifford had died about six months before, though Thompson was unaware of this. Dead Artist's Work Duplicated Meanwhile Thompson was recording on canvas the visions of landscapes that haunted him. In July, 1907, having mean- while heard of the death of Gif- ford, he decided to visit the home of the artist and the scenes of his activities. Judge of -his consternation when, on entering the abandoned studio, he found himself face to face with a painting by Gifford, practically a copy of one of his own sketches! As this sketch had been placed in the hands of Dr. Hyslop in New York, these extra- ordinary facts are established on incontrovertible evidence. There was other evidence of the same character, all pointing in the same direction, that Thompson’s activity was directed by another per- sonality, that of the deceased artist, Gifford. What are we to think of these strange reports that come to us from persons of high repute? It is hard to say. The correct attitude seems to be that of the open mind. communication that opens the door ~~ for intercourse between living people and the discarnate spirits of the de- parted. Of the evidence adduced in 67 Mr. Guthrie draws a circle and Miss Edwards reproduces them. She cannot see or touch Mr. Guthrie

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Clamping Down Cloth ‘THE old method of holding.a number of layers of cloth to be cut was to put heavy iron weights upon them. There is now an invention that not only holds the cloth firmly but also counts the layers. A metal base is clamped to the cutting table, and upright brackets on each end carry each an arm which holds a connecting rod and a blade to which are attached plungers that firmly hold the cloth. An is attached to the automatic counter bracket platform. The clamp is screwed to the table and the counter is set at zero before using it. Use a Vacuum Cleaner Di? you ever try to clean a typewriter? You get along beautifully as you dust off the top, but when you try to go beneath the surface your troubles begin. Your brush, be it long and thin or short and fat, won’t reach all the hidden corners. A vacuum cleaner will help you out. It will suck up all the dust and bits of paper that cling so persistently. The best attachment to use for this purpose is the thin flat one known as the mat- tress attachment. ~“~4e am «= ae a at Re, en eee ~ hE cae he ee _ Se af SOE A RE cect cit sae hata ‘THE bards do sing of poor Butterfly, the Japanese maiden, but none of them think of singing about the poor butterflies above. Their lives were sacri- ficed just to decorate some fair lady’s serving tray. The butterfly wings are placed under the glass top and are practically airtight. But should the tray receive rough treat- ment, the wings would crumble and the entire effect be ruined. Insect decoration becomes more and more popular. Recent- ly a German made a crown of bugs, A Gasoline Broncho N a horse and stock show held in Denver, Col., an automobile was used as an added attraction in the hurdle-jumping contests. Much to the surprise of the horsemen, it showed extra- ordinary jumping powers. With the greatest ease the car leaped eighteen feet through the air, clearing the five-foot hurdle like a bird. To add to the effect, a papier mache horse’s head was attached to the front of the car and a long rope tail at the back of the machine, while the driver of the automobile was attired in jockey’s uniform of racing silks and cap. The feat was repeated several times during the show. A Mastodon Souvenir HE ancestor of the elephant, the mastodon, ages ago roamed . wild through the forests of Kentucky; it is cer- tain that he did, for once in a while his bones are dug up. The latest and largest “find” is a huge tusk of solid ivory, a fossil, weighing 156 pounds and 9 ounces. It is 6 feet 10 inches long and was un- earthed by a steam shovel at Ludlow, at a depth of 35 feet, ina gravel bank. A foot or more is missing from the thick end of the relic and probably 9 inches are lost from the small end, but the tusk is no small sou- venir of ‘“‘elephant-days”’ in old Kentucky. New Typewriter Clamps ‘TRE typewriter below looks like an ordinary typewriter, but it isn’t. It is equipped with vastly improved paper clamps ‘‘which are mounted slidably with relation to the scale bars at the side front of the platen’’—so the patent paper tells us. In other and more simple words, the clamps that hold the paper down are made so that they may be pulled back from the paper and automatically locked in place when the typist wishes to correct an error.

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July, 1920 Training Aviators With Terra Cotta Bombs BoMBs of low explosive force, made of terra cotta, and loaded with black powder and shotgun ammunition, have recently been brought into service at Rockwell Aviation Field, San Diego, Cal., for training United States military avia- tors. ; These practice bombs have little destructive force. They are loaded with just enough explosive to burst upon striking the ground, producing a dense column of smoke that enables avia- tors flying as high as 20,000 feet to observe their contact. up for the lack. work. ance of an eye. Bidding by Push-Buttons at Auctions ‘THE bustle and noise attending an auction do not meet the approval of the easy-going Dutchman, so in Holland there is a quiet electrical method of conducting auctions. Every bid- der receives a number, and must take a seat marked with the same number. On the stand of the auctioneer is a dial with a pointer indicating prices of the sale. The tablet bears as many numbers as there are seats in the hall, and each number is elec- trically connected with the seat carrying the corresponding number. When the prospective purchaser sees a price to his liking on the dial, he presses a button on his chair and the pointer stops. Sliding Down the Neck of Dog’s Head Rock NOW is unknown in western Australia, but the boys of Albany, a seaport on the southern end of Australia’s most westerly state, have in their town a slide and natural curiosity combined which helps make It is a huge rock, called Dog’s Head from its remarkable resemblance to the head of a great mastiff. The height of the head is about twenty feet, and the length of the head from the tip of the nose to the base of the neck is thirty feet. neck that the Albany youngsters use as a slide. The rock shows signs of having been worn away by water action in earlier geologic periods, and later erosions completed the In the picture the boy’s cap has fallen into the right spot to give a realistic appear- Here Is Still Another Way to Fool the Fish € OW delicious that looks!”? Mr. Fish remarks when he sees an attractive object floating by. Indeed, it almost looks like another fish, one just the right size for a good meal. So Mr. Fish makes a lively leap toward his victim. He takes a big gulp, and lo! he is caught upon the metal hook that dangles below the colored body of the “‘fish.” This artificial bait has two revolving propellers. As the line drags it on the water these little wheels turn, and give the object a semblance of life. It is the It Pays to Advertise—Proved Again ANYONE who doubts the value of advertising, take heed! A German who owned a cigar store found business very dull; whereupon he covered the entire front of his store with cigar-boxes. Immediately his business increased enormously. He had to hire extra help in order to handle the crowd. Hardly a cigar smoker in town could resist the appeal of the empty boxes; that town, by the way, was Bremen. Recently the owner of a drug store filled his show-case with powder-puffs because he had too many in stock: there were sev- eral new powder-pufis in action that night. It proves again the power of suggestion and how it pays to advertise. bs g & ee is 2 td hd hs

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ee ont eee ae Its Edges All Curve A NEW type of violin has been invented which has only rounded or curved edges. While generally con- forming to the dimensions of an ordinary instrument, the novel violin is made so that the top and bottom come into direct contact by a curve at the sides. It is claimed that this greatly improves the tonal quality and renders the instrument stronger than it would be if straight sides were used. Thechin-rest for the curved body .has to be specially arranged, and the clever com- bination of a chin-rest and tail-piece is the result. Mr. John T. Anderson, of North Carolina, is the inventor. Popular Science Monthly This Bank Lends Radium RADIUM is very precious, since. it is both scarce and expensive. Yet it is greatly needed in hospitals for the treatment of. cancer and similar diseases. There has recently been established a radium bank, which will be conducted just as if it were a regular bank. Radium is deposited in it, and lent to doctors or hos- pitals at a regular rate. The first deposit of radium is shown in the picture. It is valued at five hundred thousand dollars. Hospitals that heretofore were unable to buy radium will now be able to borrow it. The new source of supply will make its use more general. DRYDOCK’S life is nothing but one repair after another. It is always taking in crippled ships and making them whole again. After years of this sort of work, the drydock is all Short Telephone Booths VERY time you telephone from a booth you feel sorry for Aida, who suffocated so nobly with her lover. But there has been invented a booth in which you do not suffocate; neither do your words get out. The booth reaches just below your waistline. You pull a cord and the booth enfolds you. worn out and needs repair itself. Then it visits another, larger drydock, and for a while receives the care and attention it had always given to others. Below you see just such a drydock. It was When the Drydock “Goes to Drydock” Otnrer located at Hoboken during the war and did its bit nobly. But when the war ended, it was badly in need of repair. It was towed down the river and is visiting a brother drydock. 70 Popular Science Monthly Ju

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July, 1920 night. sleeper’s face. Asleep in a Warm Straw Blanket “ONE that wraps the drapery of his couch about him, and lies down to pleasant dreams” is shown below. His couch and drapery are of straw. He is a Siberian soldier and he is ac- customed to lying down to sleep wherever he happens to be at It is very cold in Siberia. From the peaceful! look on his face we imagine that a blanket made of straw must be very warm and comfortable. holes and a square cut-out for the It has arm- ‘How Much Water Is in the Milk? CHEMISTS can take a pint of milk or a piece of bread and tell exactly how much water it con- tains. The process ordinarily em- ployed in testing for moisture occu- pies considerable time. There is a new moisture-tester which reduces the time from seven hours to just twenty-five minutes. The system includes a vacuum oven, vacuum pump, a cooling desic- cator, a water-circulating pump, and the motor that operates the mechanism. Instead of slowly drying, the substances are subjected to just the right temperature, and the precise circulation is permitted, to make sure the quick determining of the amount of moisture. It Does the Work of Ten Men GREAT. trouble - saver for street-car line superintendents is a small automobile truck with a tub for sand or salt fastened to the rear end of the floor and provided with a_hose to distribute the tub’s contents. The New York State Railways originated the scheme, and found that witha one-ton truck soequipped, and carrying a reserve supply of salt and sand, they could beat the best record of the sand-car at sanding tracks and keep switches salted that it formerly had taken ten men. to patrol. The plan needs only two men to carry it out, one to drive and the other to sit at the rear of the truck This Motorcycle Acts as a Dynamo M OToRCcYCLEs are not always used as conveyances. The one below, for instance, was used as a generator and sup- plied an entire town with electric light for an hour and a half. The usual exciter generator was out of commission, and the motorcycle supplied the motion. The motorcycle was placed on a stand and the tire was removed from the rear wheel. A belt was slipped around the wheel and the pulley of the exciter. When the engine of the motorcycle was started, the belt revolved and the entire plant was able to run. The motor was run on a wide-open throttle all the while. July, 1920 71 to direct the stream of sand or salt. Cannibals Once, Potato-Eaters Now "THE Maoris, once cannibals, now subsist chiefly on potatoes. The kumara, or sweet potato, grows in about forty different varieties in New Zealand, and the Irish potato was introduced there by the early European settlers. There are many natural hot springs throughout the island and the Maoris cook their potatoes in them. The potatoes are placed in fiber baskets and submerged for a few minutes. The Maori people are Polynesians, and are known for their war-like tendencies. During the recent world war three thou- sand Maori warriors served with the Anzacs. As may be noted in the picture the Maori women-enjoy a smoke while they peel potatoes.

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ST tate and forward in every line of science: one year the doctors promise to make a new man of one by removing his appendix, and the next authorities are all in favor of removing tonsils. And now the pendulum is swinging fast in the science of electrical com- munication. First Morse showed how to make a telegraph system with a battery, a key or switch, and an elec- tromagnet that would “click” when an electrical current passed through it, and a wire between the key and the sounder. In his system the electric current from the battery was allowed to pass along the wire and back through the earth. je pendulum swings backward What's Wrong with the Telephone and the Cable Then Bell substituted a transmitter for the key and the sounder by a tele- phone receiver, which he skilfully patterned after the drum of a human ear. The art of telephony was born. But the telephone lines with a ground return were noisy; current from any trolley line might in part return along the same route as the electrical cur- rents that carried the speech. So Carty, wizard of the present telephone system, gave to each telephone line its own metallic return, and the modern telephone system was created. Through these early days of the art the swing of. the pendulum was always toward more wire. The wire telephone couldn’t cover extreme distances until sensitive little boosters were devised for amplifying its feeble currents. Even then it was not available for trans-oceanic com- munication. Speak into a telephone transmitter and you set up rather rapid changes in the amount of electric current flowing through it, and hence in the amount that flows along the wire to the distant receiver. The varia- tions of current at this end vary the pull of the electromagnet on the thin plate or diaphragm of the receiver, and so cause it to move in the same way as did the diaphragm of the transmitter that your voice actuated. On a long line, however, there is a curious effect of capacity. It takes a little time for the current to flow into the wire, and none can flow out at the distant end until there is enough to per- mit an overflow. Only the variations in current which are caused by the telephone transmitter are useful in By John Stuart giving intelligible speech at the distant end, and they are so rapid that no sooner does the wire start to charge up with more current than the trans- mitter diaphragm moves so as to supply less current. The result is that very little ‘‘juice” flows out of the dis- tant end. Professor Pupin solved this problem for wire telephony by inserting a coil of wire every so often along the line. More wire, you see; for the pendulum was still swinging. Curiously enough, if the current once starts going in such a coil, it tends to keep on in the same direction; so the electrical inertia of the coils helps to offset the capacity effect of the telephone line. But even this trick didn’t help the telegraph engineers who had to work with trans-oceanic cables. The capac- ity effect is much worse on cables than it is on open-wire lines, so that the introduction of coils is apparently impracticable except on short lengths, as across a bay. There are no nice places to install the boosters or repeat- ers, for they must be maintained by operators. The poor oceanic teleg- rapher had to work at slow speeds, and also learn to read little humps in the ink line traced by his recording appar- atus, instead of working with a sounder. So far, the pendulum swung toward more wire. But meantime it was get- ting ready for its swing in the opposite direction toward practically no wires at all. Three Hundred Times Marconi Was Told about his Baby Wireless: wasthe next swing, and huge ‘stations :were erected for trans- mitting across the Atlantic. But wire- less isn’t secret. It isn’t secret even for its own wizard Marconi. Accord- ing to the Manchester Guardian, Signor Marconi and his wife, having left their baby sick in Rome while they crossed the Atlantic, were to be kept informed by the nurse on the wire- less. She radioed, ‘“‘Baby is better.”’ Eiffel Tower, Carnavon, Poldhu, Clif- den, and other stations received the message, and retransmitted it as a matter of courtesy. Three hundred times. did the signor receive this message during his voy- age. 72 Popular Science Monthly Forty Talk Over the Same Line Although it is done by wireless, wires are used Quderwoo U The man who showed the ‘world how wireless messages can be sent forty ata time over a bare wire, and thus“combine wireless with telegraph and cable transmission nderwood anh anremnanmiannmme2424648 82 6.0 828 34 @

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July, 1920 Now the pendulum is swinging back. From no’ wires at all, Major-General Squier is leading engineers to the use of a single bare wire between stations as a guide for the radio waves. Along this wire he proposes to guide, not a single message, but simultaneously as many as forty different messages. Multiplex guided wireless is the next swing of the pendulum. But the General and the like work just as well in an office building having a direct or steady current supply as in a village house where the current is alternating. The thing that counts is the effective value of the current, and not its alternations. In the same way, the rapidly alternat- ing current of radio practice is just as good for being modulated by the voice rent will mean corresponding changes in the intensity of the direct or one- way current, that gets through the detector. It is this one-way current that is used to operate the receiver, just as in ordinary telephony. Such high-frequency currents have one enormous advantage over a direct current to carry the telephone message. This advantage lies in the fact that each high- doesn’t care whether the uninsulated wire is above ground or below, or even under water. Hence his method is / applicable to trans- oceanic communication —not only telegraph, but telephone. He has tried it out over short distances, between Fort Washington in Mary- land and Fort Hunt-in Virginia, and -also at $2,000 a mile. Wireless Messages by Wire Major-General George O. Squier, of the United States Signal Corps, sees no hope in developing cables and telegraph’ lines. can be sent each way at a time over a submarine cable, and the insulation costs from $1,500 to He has invented a system combining wireless with telegraphy and cabling. In this article we tell you how he would use bare wires to send wireless messages—forty of them at once over a single line.—EDITOR. Only one message frequency current may be separated from all the rest by applying a principle known in the art as “‘resonance.”’ Just as the trained orchestra leader can attune his ear to any instrument of his or- chestra, and apparently be oblivious to all other notes, so a radio-receiv- ing set may be made selectively sensitive to one of the: Signal Corps stations in New Jersey. It looks like a marvel that one wire can guide forty different telephone conversations without their mutual and destructive interference. To the radio engineer, however, this part of his scheme is commonplace. In ordinary land-line telephony the transmitter varies a current that comes from a battery, and that would other- wise be perfectly steady. It makes this current increase or decrease in response to the motion of the dia- phragm of the transmitter, and hence causes similar variations in the re- ceiver diaphragm. But in radio the current that the transmitter dia- phragm varies, that is, modulates in accordance with the voice, is not a steady current at all. It is a specially generated current, which increases and decreases alternately, but at an enor- mously high rate, thousands and in some cases even a million times a sec- ond. Such an alternating current varies too rapidly to affect the receiver diaphragm, and, even if it did, it wouldn’t make an audible sound because the human ear can’t detect sounds from drums that are vi- brating faster than twenty or thirty thousand times a second. How “Wired Wireless” Works What counts, in the case of such a high-fre- quency alternating cur- rent, is the ‘‘effective value,” as it is called; that is, the amount of steady current that would produce the same heating effect. Electric heaters, lamps, ind by. 5 as is the steady current of early wire telephony. There are also many different de- vices—or radio detectors, as they are called—that, like electric heaters, respond, not to the rapid alternations in the current, but only to relatively slow changes in its effective value. .The vacuum valve (a kind of electric lamp) is the most justly famous of all the detectors, and is the ultimate prize of every junior wireless amateur, whose pocket-book compels him to use the less efficient and older style ‘‘crystal detector,’”’ which consists of a metal point resting on a galena crystal. Such a crystal device will pass current most efficiently only in one direction and practically not at all in the other direction. What flows across the con- tact points, then, from a source of high-frequency current, is merely a one-way current. Any changes in the intensity of the high-frequency cur- ~sbieiaeaal This is a tank in one of the buildings of the Bureau of Stand- ards. General Squier laid bare wires in the water and showed experimentally that it was possible to send wireless messages along the wire-under the water. Forty can be sent at one time 73 only one of many high- frequency currents. Just as we distinguish notes of mus- ical instruments by their pitch,— that is, by the number of vibrations a second that the instrument sets up in the air about it,—so the “‘tuned cir- cuits” of radio-receiving apparatus dis- tinguish between different ‘‘pitches” or frequencies of ether waves. Sending Many Messages Along a Single Wire Over the same wire or through the same ether we may send many differ- ent currents with their different fre- quencies of alternation, and have each selected and received only by its own receiving circuit. Each of these high frequencies may be used to carry a telephone message. A multiplicity of messages is thus sent through the ether without confusion. Of course, where two or more sending stations try to use the same high frequency to carry their individual messages, there will be interference. General Squier put the case before the National Academy of Science re- cently as follows: “In ocean telegraphy the elaborateness of line construction has reached a practical limit. The most promising hope of improv- ing ocean cables is to aban- don the present method and to start with the bare wires in water, using high- frequency current.” If that dream is real- ized, before long we may be able to say to some international ‘“‘central:’ “Give me Paris, East 238,375.”

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Popular Science Monthly Everything to Make Housekeeping Easy In this combination tele- phone and lamp the ugly mouth-piece is hidden by a flower-decked lamp-shade Did you know that an old tin funnel will make an excellent twine-holder? The twine runs down through the tube Three times a day the year round the house- wife has dishes to wash. Why not install an electric dishwasher? You will eliminate red hands and all the other disagreeable things connected with the drudgery of dish-washing This clock is intended for the baby’s room. The limb of a tree with It is painted in colors the surfaces exposed for the youngster where the lesser limbs have been cut. off makes an unusual lamp = ae ) & _— er learning to tell time A new kind of coat- hanger folds up so that the hanger measures two by four inches and fits in the pocket Flowers wrapped in soaked newspaper will keep their fresnness if sent on a long journey. Wrap the stems singly A nut is put between the two lead con- This mixer for the housewife is twirled Parcels may be fastened securely, and tainers and a sharp rap is given the nut- between the two hands. It is free from yet be readily opened and closed again, cracker. The kernel comes out intact all metal parts to injure the contents with this simple but effective sealer 74

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P July, 1920 - | With this new vise the work-bench mechanic can increase his output, be- cause the vise is mounted on a swivel that enabies him toturn the work to the most convenient position A new transveyor truck slips under the heaviest loads and trundles them away with ease. The brake attachment is intended to ease the load down in- clines and keep the truck always well under control 2? Do That Hard Work with Tools DRAW-ROD (TO CHUCK The air-operated three- jaw combination chuck is designed to combine maximum power with minimum weight ‘and simplicity of opera- tion. It is serviceable for severe duty. The coupling is being wide- ly used in rolling mill installations where con- ditions are always hard The illustration shows how one-man can easily handle a 750-pound barrel. The handler is used for tipping bar- rels to as well as from an upright position with very little effort In cutting several thirty-six-inch shafts, it was necessary to cut through twenty-six-inch solid steel. The illustration shows how a cut- ting equipment accomplished this The ehute releases on coal gondolas are hard to operate. Here is a new car-wrench that releases automatically Re This device is designed for severe service in con- tinuous or reverse drives. The coupling consists of two toothed disks, one being keyed to each of the shafts to be connected 75 The polishing wheel is first coated with glue, then placed in an arbor, and rolled in the emery-trough

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eR EOE 505 FPR OI Popular Science. Monthly es ae fdas a cay dg a a Sa a Se eS La Nome Wgecooe The Latest Idea in Flexible Metal Tubing HE considerable use of both large and small sizes of flex- ible metal tubing for carrying oil, fuel and hot air on airplanes has resulted in an improved type which is now coming into more general use on passenger cars and motor trucks. In ordinary tubing, the flexibility is secured through the sliding action of one strip of metal on that next to it. Provision against leakage when the metal wears slightly is se- cured by inserting a strip of soft packing between the two, but this, too, wears and results in the tubing losing its gas or water tightness. In the new type of tubing, the flexibility is obtained entirely through the give of the metal itself instead of at the seam or joint. Run the car upon the platform truck, and it is quickly carried to its stall Garaging Cars Without Damage ORE dented fenders and more scratched bodies, besides lost time and temper, are caused by at- tempting to back automobiles into GARAGE ENTRANCE (BE DE WALK STORAGE PLATFORM ; | ios — a | 3 wa ¥ Creer ele r vy } fT os hie be : TRANSFER TRUCK» | hE B8 Cage 9 We 68 . . o Bef Ahh ages OB AAeS P\4-TRANSFER TRUCK 68 ef AABB AY fA storact patrons a GARAGE ENTRANCE The diagram shows the transfer truck tracks between the rows of cars their stalls in public garages than in other service done in such garages. This is caused by the fact that the storage space is so valuable in even the smallest garage in our large cities, that every inch of floor space must be utilized. One Allentown, Pa., garageman has solved the problem and in a simple manner, by means of two transfer trucks, each running the entire length of the building. Car storage space is provided between each of the tracks and the walls of the building and for a third row of cars between the tracks themselves. FLEXIBLE BEND (NO PACKING) The joints in the tubing are made water- and gas-tight by being set under high-pressure ma- chines. This kind of tubing affords very great flexibility An Airless Automobile Tire that Will Not Puncture HERE is no question about the easy riding qualities of the pneu- matic tire for all sorts of vehicles. Unfortunately, pneumatic tire casings blow. out and inner tubes puncture. In- ventors have been working since the inception of the pneumatic tire to produce a type of tire or wheel which would give the same degree of ease in riding as the pneu- matic but have none of its puncture or blow-out draw- backs. There seems to be no end to the attempts made to devise one, but J. Oscar Smith, of Moberly, Missouri, inventor of the combined tire and wheel shown in the illustration, has made use of new principles. The wheel is driven in the normal manner from any type of axle. Rigid tubular spokes extend from the wheel hub to the rim which is made to fit a clincher tire VOLUTE CAM SPRING ADJUSTMENT aie DUST -PROOF SPOKE COVER TIRE PRESSURE INDICATOR This combined metal tire and wheel does away with tire punctures. Metal springs give ease of riding similar to that of air-filled tires 76 CLINCHER TIRE BALL JOINT » AND SHOE SIL DUCT AND TIRE SPRING VOLUTE CAM casing. Extension members in the tubular spokes hold the casing ex- tended under spring pressure as shown in the cross-sectional view. ' The inventor claims that the spring support of the casing will cushion the ve- hicle and load as effectively as an air-filled inner tube; that the casing will last longer than with the ordinary tire and that punctures are made a thing of the past. The last claim is undoubt- edly true, since there is no inner tube to puncture and no compressed air to escape. The other claims are open to argument and the wise tire user will consider with the ease of riding, the rel- ative cost of the tire and wheel, its weight and cost of upkeep and repair. Panilar Smenre Manthla

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July, 1920 Change the Speed with Your Foot RESIDENT of Brooklyn, Charles A. Marston, has patented a selective gear control with but one pedal for all speeds, including reverse and service brakes. It is designed to eliminate the objectional features existing at the present time in the Ford arrangement of three pedals close together. With this device the operator needs to use only one foot to make all of the speed changes without removing his It does away with the hold- ing of the “low and high” pedal in neutral position with the left foot, when using the foot brake or reverse with foot from the single pedal. the right foot. The pedal, being free to slide side- wise, centers itself when released mid- way between its lim- its of lateral travel. If it is desired to start the car for- ward the operator would thrust the ARM pedal to the left and a press downward, at Low (eo the same time re- leasing the hand —— brake. To go into BRAKE high the pedal is let go which immediate- ly centerizes itself so that when it is nec- essary to stop the pedal is merely pressed downward. ge a\\ Gear shifting is all done with one foot on this Ford which has selec- tive gears and a sliding pedal SINGLE =~CONTROL PEDAL MOVABLE ewe) charge. California police look for stolen cars from this roadside station and thefts are reduced SS. To Catch Automobile Thieves N California, automobile thefts have become so common that special thief-catching stations like the one shown herewith are being erected on the outskirts of San Francisco. Each station will be connected with the head- quarters police station by telephone and as soon as an automobile theft is reported, details of the car’s make and style will be furnished to the men in All cars of the same make as those reported stolen will be stopped and inspected, and the in- nocent motorist’s good-nature may be sadly taxed. Loads a la Carte from a Motor-Truck Body NE of the greatest items of cost in laying concrete highways is the cost of the manaul labor in handling the sand and crushed stone from the points where they are dumped to the chute of the concrete mixer. Because these materials are usually dumped on the ground as near as possible to the mixer, wheelbarrows must be used to carry them to the mixer chute. The ratio of the mix is also done at the same time, a certain number of wheel- barrows of sand and stone being used to some set number of bags of cement. This process is wasteful in that more labor is required to clean up after the mixer has moved ahead in the pro- gress of the work. The above is the old method of doing the work. The newest way is to employ a special compartment motor-truck body which dumps its measured loads of mixed sand and stone directly into the mouth of the mixer chute and thereby does away with all handling and measuring and the labor of cleaning up. This new body forms the most interseting part of a special highway construction truck now offered by a New York truck manufacturer. When the truck is desired to carry machinery and the like, both sideboards and body tail- gate, together with the compartment division boards, may be removed to provide a flat platform body. There are five crosswise division boards hung from rods supported at the ends on the top of the body sides. Each board is held in position by three vertical plunger rods whose bottoms extend into holes in the floor of the Ao Bag Ee ~ en, ® oe The truck runs under the dumping station and receives grade loads ina short time ‘July, 1920 77 A new way of dumping loads is to employ a special compartment truck body which measures its loads

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Se eee i 1 | 1) on A Stim fea sty sacmnAAERRENNE PERE e ae 2: AA oe Popular Science Monthly . Why Don’t You Buy Something Here is the very latest in disk wheels for the automobile. These are made of thin aluminum or lygnite, the lightness of which is notable A new valve-lifter has no springs or catches to get out of order. It : can be used to remove pp the valves of an auto- mobile, truck, and of The _ peculiar shape of this new wrench allows it to get behind the carburetor of a Ford car One automobile manufacturer does away with human failings by providing an automatic brake-equalizer that puts pres- sure on both brakes equally a tractor engine as well Equipped with a newly invented turning gear, this truck is in use at a London railway station. The device, which is operated from the driving seat, enables the truck to be turned around in its own length The three-wheeled taxi- cab has appeared in Ber- lin. The new vehicles help to improve the bad traffic conditions now existing in that city The back interior of a sport- ster’s front seat forms a table for writing in the car CAP NUT DRAWS VALVE UP TO SEAT VALVE = SPRING X a . = Rv An inner tube is no better than its weakest part. A new tire valve will greatly assist in maintaining the amount of inflation ©. Keystone View Co. that the proper With a view to future expansion, a bus company has con- length of tire life structed one of its garages.on the plan of a sectional book- demands, and pro- case. The day more space is needed the additional story long its usefulness can be added to accommodate the increase in business 78 Popular Science Monthly

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‘July, 1920 New for Your Automobile ? Built for automobiles and motor-trucks, this new tire combines pneumatic tires with an outer tire of soiid rubber to give greater mileage and protection against punctures When a battery - is opened by the old method, it is necessary continually to reheat : Here’s how they do it at the automobile shows. The fire ~ nace ng ordinance forbids gasoline. Tiny electric locomotives haul jan sm aan te the small gasoline-driven cars up the incline into the hall A moving-picture director is the de- signer and owner of this automobile which has a minia- ture bar in the back of the forward seat Truck chains are difficult to attach and detach, and necessitate real labor. The one shown in the illustra- tion is instantly attached and as readily removed and it will save time. It has only a few parts The dash instruments are all in one frame; amme- ter, speedometer, clock, gasoline, and oil gages are centralized and glass- covered as in the picture Il] PORCELAIN The self-ventilated spark-plug is pro- vided with a ball- check valve through which air is drawn to keep the bottom of the center elec- Photographs of riders being thrown from horses are common, but trode free from Hiding the extra seats on a here is one of an automobile in theact of overturning. It was any carbon or oil sportster is a new and attractive taken on a French race-course at the instant a car tipped over idea. They look like drawers 79 y July, 1920

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tien, dinetinneneemeeaee a Popular Science Monthly Keep an Automatic Fireman Under the Hood T last the idea of the fire prevention sprinkler system which has achieved such wide use in all forms of buildings, has been applied to the automobile and motor-truck by the develop- ment of a small sprinkler bottle which is placed under the engine hood and automatically empties its contents over the engine when the heat becomes sufficient to melt the fuse forming the cork of the bottle. The successful application of this idea to the motor vehicle is really one of the greatest steps forward made in recent years, for this type of fire extinguisher has many advantages not en- joyed by any other type hereto- foreemployed. In the first place, insurance statistics on automo- bile fires show that ninety-five per cent of all automobile fires originate under the engine hood. For this reason the sprinkler is placed on the front side of the dash under the hood where it is almost: directly above the fire and can stop it before it really gets started. There is no running * No chance of engine ‘fire in an auto- mobile having this extinguishing device about, taking up seat cushions or rummaging in tool boxes to get the ordinary type of extinguisher while the fire is meanwhile gaining headway. The sprinkler, which is made out of a green-tinted glass bottle, is filled with a special chemical compound and placed neck down- ward in a bracket attached to the dash. A fire is no sooner started than the fuse at the bot- tom of the bottle is melted and a fan-shaped torrent of chemical sprayed over the entire motor. An overheated engine cannot melt the fuse. Only an actual blaze will put the instrument into operation. It is the only combined automatic and hand- operated fire extinguisher on the market, for in case of fire in an- other part of the car, the bottle may readily be slipped from its bracket and employed by hand. The fluid is chemically sealed by a special gum process at the fuse and will thus last indefinitely without chemical change or evap- oration. The fluid will not freeze and is a non-conductor of elec- tricity. It will not harm or burn operator or materials. When exposed to the air and heat, it effervesces, forming a blanket of heavier-than-air ‘gas that smothers the flames. This Self-Reliant Truck Is Its Own ‘Body Booster NLY when a motor-truck is mov- ing is it earning profits. No number of $5-a-day shovelers will keep a truck moving. Of the usual causes which prevent a motor-truck from being continually in motion from morning till night, that time taken for loading and unloading is perhaps the most important. Trucks must load and unload, for no sale is complete until the goods are delivered. Those truck owners who deliver sand, stone, earth, rock, coal and the like will be interested in the novel type of dump _ body shown herewith because it helps to reduce that impor- tant factor of unloading time. It also eliminates shoveling when the load has to be depos- ited other than on the ground. While in general appearance the body is little different from the ordinary steel dump body such as those used by contractors, it has many unusual features. The most important of these is that it may be raised so that the rear end of the body is eight to eight and one half feet above the ground. This per- mits bulk material carried to be chuted end or side of the body into bins or hoppers without shoveling. Because of the steep angle of inclination of the bedy when in this position, from two to six tons of bulk material can be dumped by gravity in forty-five seconds. The body is elevated by means of an unusually heavy hydraulic hoist placed on the chassis frame directly back of the driver’s seat and oper- ated by the engine. The rear end of mera the body may be pivoted to the chassis frame and made to dump just like an ordinary body when there is no neces- sity for dumping at a height above the-ground. The extra high elevation is secured by mounting upon two pairs of folding cross stilts which open up as the body is raised by the hoist. When the body is lowered, these stilts fold underneath the body floor. The fact that the body functions like an ordinary end-dump type makes it suitable for transporting a great variety of miscellaneous materials. The high-lifting qual- ities may be used to advantage in connection with loading or unloading onto or from high platforms or unloading into hoppers or bins in construction work where wheelbarrows or chutes may be filled by grav- ity. During elevation the body remains practically horizontal until the rear end has been raised to the desired height. Once this elevation is reached, the rear end remains stationary and the front end continues upward until it reaches its maximum elevation. The operator can obtain any desired elevation of the tail-gate simply by adjusting a serew mechanism which regulates the distance the rear end has to travel This truck either elevates its body load or permits bulk material to be chuted from it 80 directly from the rear upwards. a

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July, 1920 To Keep a Ford Engine from Racing F particular interest to those Ford-owners who operate con- verted passenger-car models or Ford one-ton trucks, the Ford governor shown in the accompanying views is not among those governors which do not govern. This one actually dces govern the Ford engine speed because it automatically cuts out the ignition when the predetermined speed has been reached. This does not mean that it governs the truck speed, for it is entirely pos- sible to overspeed the truck when going down a hill, even with the clutch thrown out. The governor is a simple affair, and is placed inside of the Ford timer where it takes the place of the regular Ford timer brush arm. It does not otherwise alter the principle of opera- tion or the mechanism. The Ford truck may over-speed and overheat its engine if it hasn’t a governor to control revolutions Hauling the N the great West and North- west, where the largest number of the newer automobile-like farm tractors are in use, the problem of demonstrating them on the prospec- tive purchasers’ farms and later deliv- ering them when sold has become very important. One wide-awake tractor dealer has devised a special motor-truck for carry- After the tractor is run up the burlap-covered skids on to the truck platform, the skids are unhooked Dents are “ironed” out by pressure with this tool The garage-man can now straighten motor- vehicle fenders easily without removing them How to Straighten Bent Fenders ENT and dented automobile fenders have always been an eyesore which motorists have allowed to remain. because of the difficulty of straightening them out without taking them off and subsequently repainting them. But now the garage-man is able to make a business of straightening fenders, and a profitable one too. This has been made possible by the development of a new tool that can be used for any type and size of front or rear fender which does not have to be removed from the car unless it is so badly smashed as to need renewal. The idea behind the tool is pressure properly applied. This is done through the use of two wood blocks faced with soft. pads and a series a of different sized and shaped wood and metal rollers. The Tractor to the Farmer ing the tractors home. Carrying small and medium types, it makes good time on the road. The special platform body may be applied to any make of truck and the dimensions of the various parts changed to suit the particular type of The truck has a special main part of the tool consists of a two-armed toggle frame- work, of which the ends of the arms are opened and closed by means of a threaded bolt inserted through a cross member between the arms, and turned by a handle at the other end. In operation, both the top and under sides of the fender should be cleaned of all dirt. Otherwise, the particles of dirt will be rolled into the enamel paint and mar the finish. The dirt may be removed most easily by simply rubbing off the surface with a clean, oiled cloth. The illustrations above show how a dent is removed. Saves Time tractor to be hauled. The farm trac- tor is driven up on the truck platform under its own power by means of skids covered with burlap to prevent slipping. When once on board, it is held in place while the truck is in transit as shown in the sketch. ANGLE-+~RON WHEEL-GUIDES from the end of the truck body and placed between the tractor wheels for unloading the tractor again platform, which is grooved for the_ center flanges of the tractor wheels 8]

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Popular Science Monthly Reaching the Heights of Art in an Elevator Without one few would visit the museum on the hill OULD you climb a small hill to see a wonderful painting? You may think that’s a foolish question, but the sad fact has been proved that there are thousands of people in Los Angeles who never visited the Southwest Museum simply because it is perched on a hill. The governors of the museum finally decided to install an elevator under the building, with a tunnel leading to it, thus enabling people to reach the heights of art without expending any extra energy on the way. Immediately the attendance increased from fifty or seventy-five visitors a day, to hundreds. But the tunnel was crude and did not live up to the museum itself. So now the governors have decided to finish it off in the style of the ancient Maya architecture. The Maya de- veloped a splendid civilization more than a thousand years ago in Central America and Mexico, and had a distinctive architecture. Their mag- nificent ruins still stand. The late Dr. Hector Alliot, a dis- tinguished scientist and for a long time director of the museum, had always wanted to preserve Maya art. The Maya portals of the subway will be a memorial to him. The subway and shaft of reinforced By John L. Von Bion Miss Adelaide Chamberlin is super- intending the job. The tunnel and elevator will be finished off in the style of the ancient Maya architect- ure, with which Miss Chamberlin, as an archaeologist, is well acquainted concrete will cost at least $50,000. Nearly a year has already been de- voted to the work. The tunnel is two hundred and eighty-one feet in length, and its mouth is just above the grade of the nearest street. The ornamentation of the waiting- room, subway and portal, isan immense task and will require years for its com- pletion. Miss Adelaide Chamberlin, assistant curator in archaeology and ethnology of the museum, is directly in charge of this work. Miss Chamberlin, a frail girl of remarkable attainments in science and art, and a delver in archaeology since she was nine years of age, has superintended the entire subway enterprise and made all the designs. She has com- pleted the one for the portal. The bold use of serpent forms, characteristic of Mayan art, is strik- ingly exemplified in this magnificent piece. The modeling of this, together with all others in the scheme, is in the hands of Miss Marguerite R. Tew, a sculptress of talent. As the Maya never built a true arch, but achieved only a peaked effect, that will be reproduced in the tunnel ceiling. Along the walls will be fifty sculptured pilasters and bas- reliefs alternating with deep niches containing habitat groups illustrative of the lives, homes and costumes of the aborigines of the southwest. The entire subway will be brightly lighted with an invisible indirect system. The Southwest Museum is a public institution privately built and sup- ported. It cost more than a quarter of a million dollars. The building itself is two hundred feet long. It has a tower one hundred and twenty-nine feet high or low, extending downward as far as upward because of the angle of the hill on which it is set. SUBWAY 281 FT. LONG BY OCTAGON f 4 WAITING“ROO The thirst for art was not great enough to induce people to visit the museum on top of the hill ce er ne en 82 When a tunnel and elevator were built, the attendance increased tremendously

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July, 1920 Cutting Down Operating Expenses A little care and attention every so often will do wonders to your car By Fred Gilman Jopp RE you one of those motorists who A are afraid to take long trips for fear that something will happen to your car that you won’t know how to repair? You needn’t be for all we know about motor vehicles has been gained by observation. Some fellows seem to be always having engine trouble, while others are constantly fooling with their tires. Another keeps his left foot constantly on the accelerator and the other on the brake, yet this chap rages like a dog with the hydrophobia when his car is towed back to the garage with a serious break-down. Nothing is more remarkable than the unparalleled advance of the auto- mobile, especially in the last few years. Carburetion and ignition troubles have been overcome to such an extent that they no longer constitute a motor problem. Engine, axle and other troubles have been reduced until they are insignificant, so there is nothing left for the owner to do but thoroughly understand what is under the hood of his car, and give it the little attentions and cares that it should and must have. of gasoline depends not only upon the grade of fuel bought but upon the con- dition of the engiie in which it is burned. It would be a good thing gen- erally if owners who are complaining about low gasoline mileage and blam- ing it on the quality of the fuel, would also examine carefully the condition of their engines. The condition of the cylinders, the tightness of, the piston rings and the condition of the valves, all have their influence on gasoline mileage. If the cylinders are slightly scored, the piston rings loose and the valves seating improperly, it is no wonder that gasoline mileage is low, even granting that the present day fuel is inferior in quality to that which could be purchased two or three years ago. If loss of power is due to a faulty carburetor adjustment the trouble is more likely to be on the side of an ad- justment which is too rich. The ex- haust smoke is usually black or will have the odor of raw gasoline. A simple test is to shut off the flow of gasoline to the carburetor and allow This oil-can combines a measure, a strainer, and a funnel in the form of a flexible spout, which reaches otherwise inaccessible filling plugs and it prevents waste through spillage of the oil the engine to run without touching the throttle. If the engine speeds up as the level of the gasoline drops in the float chamber it is an indication that too much gasoline is being supplied under normal conditions when the chamber is full. Such a mixture causes not only loss of power, but also overheating, carbon deposit, and pos- sibly pre-ignition. It is not sufficient to know that the generator with which an up-to-date car is equipped is charging when the engine is running. It must be defin- itely known that the current generated is neither more nor less than is required to keep the battery properly charged. The amount of electrical current developed by a properly functioning generator The following gives some suggestions that will keep your engine and running gear fit. If you take pride in a quiet running engine you will appreciate the advice which will help you keep away from the repairman. The number of miles ‘obtained from a gallon Stranded on a country road with a weak bat- tery. Connect a wire to the positive terminal of the passing car’s battery and the positive terminal of the stranded one, also a wire to the negative poles. This will start the stranded car and give its battery a chance to recharge is practically constant, while the amount con- sumed by the use of the various instruments which are supplied by the battery is never constant. It is evident, then, that a -battery may be either over- charged or under- charged by a perfectly normal generator. This attachable device turns your Ford into a power plant for driv- ing all kinds of ma- chinery. The fan is guaranteed to keep the engine cool and the water below the boiling-point at 1,100 revolutions a minute This motorist reasons, and correctly, that if carbon can be burned from the cylinders, it can be burned off the plugs. The plugs are put around the gas flame about an inch away, and left until the points are red-hot

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ea ARRIETA RTS Bie vith apemeneen nanan elie entire na a ve : snes a 8 Sin OT = een ri had oo ee a The general belief that the electrical system is equipped with a cutout to prevent overcharging is erroneous—it has no such duty. Its duties are, how- ever, first, to close the circuit when the generator is not operating, so that the current in the battery does not run back or discharge through the gener- ator; second, to conceal the rate of current passed to the battery when charging, but not to control the amount of current. The battery should be tested weekly to ascertain that it is being properly charged. It must be supplied with water regularly in order that the elec- trolyte may be sufficient in quantity to keep the battery properly filled. <A battery deteriorates almost as rapidly when idle as it does in use, for the active ingredients of which a charged battery is composed are constantly in operation whether the battery is in use or left standing. It is therefore evi- dent that a battery cannot be left idle in its normal condition and retain its usefulness. Next to the tires on a car its brakes are subjected to the greatest wear and tear. It is well to re- member this and to watch them carefully. Brakes require read- justment from time to time. Both the service brake bands and the emergency brake shoes, in operating against the brake drums, must form true circles or they will not take hold evenly all the way around and, of course, will drag when released. The one fault reduces the effectiveness of the brake, the other the speed and economy of the car’s performance. In many States it is

One advantage of a removabledriver’s seat is that yoti may put whatever chair is de- Here is a wicker one sired in its place.

a penal offense to drive a car with worn brake linings. They endanger not only the driver, the passengers and the car, but the public as well. Their replacement is an immediate duty. It is a simple operation, per- formed quickly, at slight expense by a reliable service station. If the rear axle makes a ‘“‘howling”’ noise when the car is under way it isa sure sign that the bevel gears are not adjusted properly, allowing too little or too much backlash. Bevel gears in use to-day have a method of adjusting the depth of the mesh obtained either by moving the whole differential unit sideways or by movement of the driv- ing pinion. Either fix it yourself im- mediately or take it to your service station. Once the gears wear into their wrong adjustment the only

An expert gives the solution of repairing curtain lights. When removing the old celluloid, rip only the inner seam. Place the new sheeting in the groove and then sew on a machine. Saved, three dollars and seventy-five cents by this simple method

In the steel casing are held six different sizes of socket wrenches. The rod on which the wrenches are held is slipped through the

Popular Science Monthly remedy is to have an entire new set installed. Wheels out of true will grind the rubber off your tires. When your wheels are not in proper alinement they run at a slight angle to the direc- tion your car is traveling, which of course produces a severe grinding between the tread and the road and wears down the casing at the point of contact in a surprisingly short time. A fairly exact way of determining whether or not your wheels are out of line is to use a straight edge and meas- ure between the felloes of the wheel or the edges of the rims on the wheels at the point directly in front of the front axle. Mark this distance carefully and measure in the same way across the wheels directly back of the front axle or opposite from where the first meas- urements were taken. The difference between these two measurements will be the amount the wheels are out of true. If any is found it should be corrected immediately. Save those old oil stove wicks that your wife usually throws away. If slit in half and laid flat they will form an excellent remover of grease and grit from your hands and save wearing out the costly towels. The wicks should be kept in a tin can and moistened fre- quently with kerosene. A very good way to prevent oil leaking out of the crankcase through the bolt holes, is to back off the studs l4 in. or so and then wind several turns of cotton twine around the loosened bolts. When the studs are tight again the leakage will have disappeared completely.

holder at the top of the steel casing, and used as a handle for removing them 84 TT VTetst sua e 3 e

A folding writing-desk was put in this town car. Does this suggest a way for you to combine work with pleasure?

Popular Science Monthly eo _~ Se

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July, 1920

AMLUDAUALOOOV 2.0L

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THE HONOR “ect

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Weed Chains for Motor Cars! Anchor Chains for Ships! Chains for Railroads! _ Devices that make travel safe on land and sea, that can be absolutely depended upon to pro- tect human life, are typical of the nature and quality of Acco products. The workers who make up the Acco family know they are doing more than making commod-

j ~~ ei { Re Se «OOF THE Pp eS i a pened ive Ching =" TlWeed Tire Chamns||== =" Passenger Cars AC CO FAMI } Y Trust

‘this gives the work of the Acco family honorable and dis. tinctive responsibility which is re- flected in every link of every Acco product—“From Plumbers’ Safe- ty Chain to Ships’ Anchor Chain.” In the-Acco family, loyalty to the work itself is rated above everything. This is true of every worker whether the job is directing all of the numerous plants, or operating a 2,000,000 pound tester, or a

Wa NY ities merely to be sold. typewriter. Y; ¥ They know thet it sie The honor of the Acco fam- Vi UW oe work that holds millions of motor ily vasa the hands of each member tii = ade de cars and trucks to slippery roads. of it, even to the youngest i \H}. — ees worker. — \|"Elweltrd Trace Chains It is their work which enables TR oie Sash Chan _|K mighty ships to ride safely at pe Re ] 6 ; is possible to say not only that aT anchor, whether in harbor or “Every Weed is Guaranteed” but that every link in-every chain made by the American Chain Company will hold for the purpose intended. helpless on a lee shore. It is ther work which makes possible the safe operation of Ff] — thousands of railroad trains. hi | () (it =>

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The big ACCO Line includes chains for every purpose—from Plumbers’ Safety Chain to Ships’

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85

July, 1920 }

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Sr csusimasonendetamaneaeasnrmannemsme eet ee ae ee ane wren oe + : 2 Extra Gasoline for Hill Climbing How the little Ford can be made to ascend a hill however steep By J. S. Chapman ORD owners who travel in moun- tainous districts will call to mind many hills that can be climbed only when the gas tank is full. Occasion- ally one meets a grade that must be climbed wrong end first, in order to keep the gas in the carburetor. As these hills occur most frequently on unmade roads, this method of going up in reverse is not only difficult but dangerous. Having been stalled sev- eral times in this manner, I have solved the difficulty by fitting up an auxiliary tank which can be turned on or off as required. A one-gallon oil can was converted into a tank. It is flat, and fits on a wooden bracket attached to the ex- treme right of the instrument board. This is the cheapest and simplest way of fitting a tank, though a more fin- ished job could be effected by having NEW POSITION OF FILLER CAP ay PATCH —— & flor f -m PROJECT THROUGH FOOT-BOARD LINE FROM UXIU | LINE FROM Lata MAIN TANK FIG3 LINE TO CARBURETOR= A one-gallon oil can is used as the emergency gasoline tank and the other parts are picked up at a very slight cost, or found about the home garage a tank especially made to fit under the cowl of the dash out of sight. How- ever, the oil can on its bracket when painted black, is not unsightly and does not interfere with the passengers’ outlook. The fittings necessary are: two 4 in. brass gas cocks, one T-piece, about 4 ft. of brass or copper tube, and a short length of \% in. iron rod. If solderless pipe fittings are obtained much time will be saved in making the joints. The oil can should be washed out with kerosene, a hole punched in the bottom and one of the cocks soldered in. Next, while your soldering iron is hot, run it round where the screw stopper joins the can and melt the stopper off. This must be re-soldered to the can on the side opposite the tap, as this side now becomes the top (Fig. 1). A patch cut from any scrap of tin is soldered over the hole left by the stopper. The stopper should not be cut out with snips, as this method leaves a ragged edge. By heating it off, a clean edge is left ready for put- ting on the other patch. The bracket can next be made of a few bits of wood cut approximately to sizes shown in Fig. 2. The bracket is attached with three wood-screws, and the tank strapped into position. One end of the copper tube can now be attached to the tank and bent forward and downward to lie along the dash. Re- move the foot-board and lead the pipe down to the pipe-line to the carbu- retor. It is now necessary to prepare the other cock by fitting it with a handle to project up through the foot- board. One end of the iron rod is flattened out, then a flat is filed on one side of the handle of the cock, and an } in. hole drilled through both, where a small bolt or rivet will hold the rod firmly in position (Fig.3). The rod is held in a vise and bent at right angles so that it will be parallel to the pipe line when the cock is open (Fig. 3). The T-piece may now be attached to the cock by a short length of pipe and the two fittings cleated to a wooden block (Fig. 4). The block is not essential, but it is much easier to attach the unit than to cleat on the cock and T-piece separately. This block with fittings attached can now be screwed or nailed onto the wood of the body just behind the dash, and the pipe from the tank connected to the T-piece. All that remains now to be done is to turn off the cock under the main gas tank, then cut and fit the pipe line to the cock and the T. Before connecting pipe line to carburetor, a little gasoline should be run through from the auxiliary tank to make sure that the pipe is clean and free from stoppages. When replacing the foot-boards a_ small notch should be cut in one of them for the handle from the cock to come through. For normal running the tank is kept full and the cock beneath it shut off. The iron rod handle runs fore and aft of the car when the engine is feeding from the main tank. On approaching a bad hill it is only neces- sary to open the cock under the aux- iliary tank, and cut off the supply from the main tank by turning the iron rod at right angles to the pipe line, thus preventing the small tank emptying itself into the big one. The height of the small tank in- 86 Popular Science Monthly a — Be. & - ai x How the gravity gasoline tank will appear when attached to the dash- board of the car. Notice that it will not obstruct the view of the passenger sures sufficient pressure to keep gas in the carburetor whatever the angle of the hill. Also a gallon of gas in a ‘gravity tank’ weighs less than ten gallons in the main tank! Incidentally this tank forms a very convenient means of carrying a spare gallon of fuel, as it can be emptied into the main tank when required, by simply turning on the cock. How a Motorcycle Motor is Started HE initial impulse necessary to start a motorcycle motor is given by means of a ‘“‘kick starter’ acting through the clutch and front drive chain. The clutch carries a. rachet pinion, meshing with a toothed sector, pivoted on the motorcycle frame. To this the starting lever and pedal are’ fitted. With the clutch engaged and trans- mission gears in neutral, a short thrust downward on the pedal engages the teeth on the sector with those on the ratchet pinion and the motor is “‘spun’”’ through the drive chain leading from the clutch to the motor sprocket. One ‘*kick’”’ on the starter results in two compressions in the motor. On being released the arm is forced back to its up position by a spring, and is held stationary by a stop. It is then ready for use when the motor is again to be started, without further attention on the part of the rider. The motorcycle “kick” starter showing the working parts with the chain cover guards removed

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July, 1920 CARDIFF GYPSUM PLASTER CO FORT DODGE, /A. f DRIVE LOCATED HERE STORAGE B/N MATERIAL - CRUSHED LIMESTONE 4a OADING HOPPERS \ 7 U TAKE UP BELT CONVEYOR SPECIFIED BY G.T.M. /8-5 PLY GOODYEAR BRAND CONVEYOR BELT 28 02. DUCK - Ye EXTRA RUBBER TOP COVER CAPAC TY — 18 TONS PER HOUR SPEED ——90 FT. PER MINUTE INSTALLED —— APRIL 15, /9/5 AMOUNT MATERIAL CARRIED TO DATE —— 125,000 TONS Copyright 1920, by The Goodyear Tire & Rubber Co. 125,000 Tons of Stone—and the G.T. M. The requirements called for a belt with character. The belt he recommended is the 145-foot Good- BELTING - The G. T. M.—Goodyear Technical Man—could see that, from the very beginning of his study of the original conveyor installation for the Cardiff Gypsum Plaster Company, at Fort Dodge, Ia. The conditions of service would be unusually severe—handling gritty, abrasive limestone, fed to the conveyor in sharp lumps averaging two inches in size. No previous experience in this mill fur- nished a working basis for suggestions. This was as much a test of the Goodyear Plant Analysis Plan as it would be of the belt. You may be sure that every item affecting the efficient operation of that conveyor went into the G. T. M.’s calculations. The officials gave him full access to plant records. He figured the belt speed per minute—90; the diameter of head and tail pulleys—20 inches; their nature—bare; atmos- pheric conditions—damp; method of loading— from four automatic chutes; condition of bed —level; all equipment in first-class shape and well attended; weight of load—110 lbs. to the cubic foot; tonnage to be carried—18 tons per hour— day in, day out—10 months a year. PACKING July, 1920 year Conveyor that is in operation today with five years of trouble-free service to its credit, and a record of more than 125,000 tons conveyed. It has gone on working amid the prevailing damp with all the unconcern of its moisture-proof construc- tion. Judging by its condition today, Supt. C. C. Collins estimates that this 18-inch, 5-ply, 1%-inch cover Goodyear Conveyor will stand up just as consistently to six years more of service. Goodyear Belt performance like this is not measur- able in first cost. The Cardiff Company’s officials noticed when the G. T. M. figured on their problem that the belt he prescribed cost a little more than other conveyors. But their investment of that little additional secured them a balanced belt, specified exactly to their conveying—an earner and a saver every hour of its life. The G. T. M. and Goodyear Belts, the idea that RS = 87 squares with your needs and the belt that we build to protect our good name, are available for your conveying and transmission. For further infor- mation about the G.T. M.’s services, write to The Goodyear Tire & Rubber Company, Akron, Ohio. HOSE*VALVES

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Margin | of Safety OUGHER, heavier, stronger in all their parts than ordinary routine service requires—Yale Padlocks, like the steel rails of the railroad, have the strength plus that enables them to successfully withstand the shock of extraordinary emergency. That reserve of extra strength, the mar- gin of safety, is in-built into Yale Padlocks. Enduring, tough metals. Test methods that check each step in material and mak- ing. Designed with the skill oflong years— each part of mechanism of the Yale Pad- lock is precise to exactness. Simple, compact, safe, you can depend with confidence upon Yale Padlocks, in the knowledge that each one is built to meet ihe demands you will make on it. The trade-mark ‘* Yale” stands for the name of the maker of Yale Products—not fur a type of lock. It is the abbreviated signature of the manufacturers. Yale Padlocks bear the trade-mark ** Yale’ asa symbol of their margin of safety. The same trade-mark that guarantees Yale Cylinder Night Latches, Door Closers, Builders’ Locks and Hardware, Cabinet Locks, Bank Locks, Chain Blocks and Electric Hoists. The Yale & Towne Mfg. Co. Makers of the Yale Locks Works & General Offices : Stamford, Conn. New York Office: 9 E. 40th St. Chicago Office 77 E. Lake St. Canadian Yale & ‘Towne Ltd. St. Catharines, Ont. Popular Science Monthly Things to Know About Lathe Tools By Ronald L. Prindle N the making of high-speed steel tools for use in a lathe, the tools are heated to a poin* where their tips begin to melt. When a tool is so heated, it is immediately plunged into oil; or else bur- ied in common salt until thoroughly cool. It is not gen- erally known that carbon steel gives the best results when heated to a dull red and plung- ed into oil. Only the _ tool point proper should be heated to the plunging tempera- ture, the heat being , slowly applied at \ first and then the blast turned on gradually. The tool should be plunged into the oil when the heat is increas- ing, and at the in- stant it reaches the plunging tempera- ture, which in the case of- carbon steel is when. it. is dull red. This is very important in the treating of high carbon steel, as heating the steel to white hot, then allowing it to cool to a dull red, makes a very poor tool. Carbon steel tools must always be tempered. There are two ways in which this must be done, the best being to plunge only the point of the tool in oil after heating it to a dull A. Bull Nose. mond Point. D. Inside Tool. Tool. Threading Tool. H. Inside Boring Tool B. Left Hand Dia- C. Cutting Out Tool. E. Inside Threading F. Round Nose. G. Straight red, thus leaving some heat in the heel of the tool. When the point becomes black, re- move the tool and rub the cutting edge with emery paper mounted on a stick. Care must be taken to watch the point closely and, as the heat is driven from the heel to the point, the color of the surface @ being polished will turn light straw color, dark straw and blue. Assoon as the point of the tool turns straw color plunge the entire tool in oil and cool it completely. The otherway of temper- ing isto cool the tool immediately after thefirst heating, pol- ish the point, slow- ly heating it again to straw color and then plunge it. Almost any kind of a grinding wheel can be employed in tool grinding, but one should remember not to draw the temper out in any way, and not to burn the tool. The tool is held lightly against the wheel and occasionally cooled in water. In this way tools are ground to the shapes shown in the illustration, the shape, of course, de- pending upon the work to be done at the time. Finally, finish the cutting edges neatly with an oil stone. An Experiment in Perpetual Motion By A. Swenson HIS is an interesting example of the transformation of infinitesimal amounts of heat into motion. When first viewed it seems to be the long- sought-for perpetual motion. The ex- periment can be performed without any special apparatus and requires only a small amount of aniline, which is inexpensive and easily obtainable. Heat some water to nearly the boiling-point and put it into a glass vessel so that the action can easily be seen. A chemical beaker is fine for the purpose. Into the _ hot ANILINE OIL self from the main body of the ani- line, the skin of the upper layer quiv- ering in a peculiar fashion after the separation. The long neck remaining on the upper surface then detaches itself and forms two or more spheres, usually one large and one small. While this has taken place the large drop which was in a more or less flat- tened form on the bottom of the beaker becomes more and more round and finally becomes spherical and after a brief interval of hesitation rises to the top and WARM WATER mingles with the water pour a quan- tity of aniline which will lie quietly for a while on the sur- original liquid. In “4 a moment another 1@ ‘e drop is released and after an interval face of the liquid. Soon however the center of the aniline will assume ¥s a rounded form and then a large drop will grad- ual otion ually detach it- 9 io 88 If you want to invent a per- is an experiment to start with goes upward also. The action is auto- matic and contin- ) uous, and owing to | the large sizeof “the drops the en- tire action can be studied with ease. machine — here

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July, 1920 jc & & we A R MATERIALS OF ENDURING STRENGTH AND WORKMAN — SHIP OF SCRUPULOUS CARE MAKE BV:D-WEAR FAR. BEYOND WHAT IT IS FAIR TO EXPECT. NO UNDERWEAR IS BVD:\WITHOUT THIS RED WOVEN LABEL. MADE FOR THE | (rode Mork fing US Pat Of and Foreign Gauntriead THE B-V:-D: COMPAN™ NEW YORK 89

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Popular Science Monthly Make big Profits hepairing Sires D° you want more money? Do you want to get into a fast-growing, uncrowded busi- ness where you can make from $250 to $500 a month the first year? Do you want to be inde- pendent? Do you want to share the profits in the richest industry in all America? Of course, you do. Then investigate the tire repair business—and doit now. The Jim Dandy Tire Repair Plant is making money for many men. It can do it for you. Fortunes have been made in all lines con- nected with the automobile industry—but none has ever offered greater opportunity than tire repairing with a Jim Dandy Plant offers you today. The tire repair men of America have a $200,000,000 business ahead of them this year. Think of it! By January 1st, 1921, there will be 40,921,076 tires in use in this country. Every one of these tires must be repaired some time. More tire repair shops are needed. Big, profitable busi- ness is waiting for them. Do you want it? Business Is Going Begging This is your opportunity. The tire repair industry needs business men of ambition and ability. The field is uncrowded—the number of tires to be repaired is increasing at the rate of 40% a year. As proprietor of your own tire repair establish- ment you will be dealing with the wealthiest and most prominent people in your community. These people will ask you for advice about tires, accessories, even automobiles—unlimited oppor- tunities for profit will be yours. And you will be in a business which is an ab- solute necessity to the community. Tire repair trade comes again and again. You will have a steady repeat business getting bigger and bigger every year. $250 to $500 a Month With your own Jim Dandy Tire Repair es- tablishment you can make your income $250 to $500 a month or more depending on your energy and initiative. Many tire repair men who have done a business of $250 the first month have increased to $500 the third month. What these men have done you can do. They started like you and learned the business. Their success is not unusual. Get started in tire repairing with a Jim Dandy plant and get started now. There will never be a better time to start.

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July, 1920 Own Your Own Business-/3e lndepe ndent HY depend on another man’s business to make a substantial income for you? Why not put your time and ability into your own tire repair business—then you will get all you earn. You can be independent just as well as the other men who own Jim Dandy Tire Repair Establishments. These men broke out of the rut, stopped working for somebody else— and started their own tire repair establishments. We Teach You FREE You can start a highly profitable business today with a few hundred dollars. One Jim Dandy Plant equips you—we teach you every- thing about tire repairing—how to start in busi- ness—how to get trade—what to charge—how to figure your cash profits. You can learn in one to three weeks—and be ready to make money. 7 It makes no difference what your present business is. You can make a success of your own tire repair establishment. You don’t have to be a mechanic. Neither do you require a college education. Tire repairing is a business man’s business. If you have the energy and the will to do, we can teach you in a short time. We have had forty-one years successful busi- ness experience. Since 1879 we have been gathering the information and experience which help you make a quick start today. You under- stand, of course, that we give you our training and help without charge. The men who have made big money are the men who have had the foresight and the nerve to break away from the crowd and strike out for themselves when they saw a chance for inde- pendence. Don’t let a salaried pos'tion keep you from your chance to own your own business, be your own master, pocket your own profits. Many a “job” has kept a man from a bigger opportunity as an executive in his own business. Your Opportunity Haven’t you often felt that you could manage the business you are in now, if you had the training and opportunity? MHaven’t you suggestions and ideas which you know would make bigger profits possible? Give yourself a chance to use these ideas where they will pay you. —— SM Msanemeseeeeees TEAR OUT HERE—MAIL TODAY In your own tire repair business you will have a chance to do the planning and give the instructions. In ashort time you can have more work than you can do alone. Then you will have assistants to do the actual work, while you give your time and thought to the active management. No previous training—no long apprenticeship —no large investment. You can get started im- mediately—open a.shop—and in a short time you have more work than you can handle alone. ‘Good tire repair men are badly needed. Your profits start the day you set up your Jim Dandy Plant. There is no city too large or town too small for you to do a profitable tire repair business. To every 11 per- sons in: the United States there is an automobile with four tires to be repaired. No matter where you are— what your: age or occupation—in one month from today you’ can be making money from your own tire repair business if you start now. Let us prove it. A Jim Dandy.Tire Repair Plant makes it easy for you to learn the business and to turn out the kind of work that brings customers back again and again. It is the only tire repair plant on the market which uses super- heated steam. Perfect work is assured even when you are a beginner. You can make any kind of a repair— and you buy no unnecessary molds or parts. You do not pay for anything that will not bring returns. The Jim Dandy has the largest capacity of any plant of its size on the market. It is fully guaranteed and backed by our long experience in the tire repair business. We have established tire repair businesses for men of many ages and professions in towns of 200 population and up and have no record of a failure. We are ready to give you every assistance. Get The Facts By Return Mail Investigate. Send the coupon below or a letter or postcard. This brings you full information—personal consideration and advice—and a big catalog. Tells all about the tire repair business. How you can make money—be independent. By return mail you can have all the facts before you You might as well make $5000 a year. It is up to you. You know you want it. Then investigate. Use the coupon below. Scheffer & Rossum Company Established 1879 Minnesota JIM DANDY TIRE REPAIR PLANT St. Paul FREE INFORMATION COUPON Scheffer & Rossum Company, 175 E. Tenth St., Saint Paul, Minnesota Gentlemen: Please send full information about how I can start in the tire business with small capital and make a good income. Also your FREE book entitled, ‘‘Your Opportunity.” IS esau Ma ee Cine, Address .... Taslhare T100N

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Popular Science Monthly ~ Six Methods of Automatically Stopping an Engine or Motor HILE there are many schemes for automatically stopping a gas engine or electric motor, the methods here described will be found to serve nearly every practical purpose. They will be found advantageous in cases where the en- gine cannot be closely watched and tended, asin pump- ing water at a dis- tance, shutting off

By Windsor Crowell into a large retort forge or furnace and when the heat reaches a certain degree the blast must cease. Arrange the thermostat so that the points are NG" | HEXAMINING 8< I INTERIOR ~ FLASHLIGHT EXTENS! } OF when a certain “Mt ananne PARTITION a pressure has been Ne soacre” reached, etc. Fig. 1 illustrates the manner in which the sparking circuit can be brok- en at a certain time of day. It is done in this instance by attaching a cord CIRCUIT TESTER MADE FROM RECEIVER WINDINGS to the handle of an sEALeED iN BOX easy working knife switch and arrang- ing it to be wound up on a drum, which Seneeoe aes islike the spool that HOLDER revolves with the winding key of an alarm clock. As the spool revolves with the ringing of the alarm the cord winds up and lifts the switch out of contact. Fig. 2 shows a gage,—steam, water or air,—with the hand in constant con- tact with the metallic face. This com- pletes the circuit to the engine. At the maximum pressure however, the hand strikes a spot of non-conducting ma- terial and the circuit is broken. Fig. 3 illustrates a thermostat in the line. Suppose the engine is driving air There are times when you want to leave your engine or motor to stop automatically. Here are six ways it may be arranged

MINIATURE PLUG WITH LEADS x am NY LOCATING OBSTACLES IN PARTITIONS 79 “COMPASS

always in contact as long as the heat remains low. Then as the tempera- ture rises the arm rises until at the proper degree of heat the points separate and the current ceases, stop- ping the power. Fig. 4 operates by the action upon selenium. There may be conditions where the engine should be stopped when a certain amount of light is ob- tained, or at daybreak. Suppose an engine is to be run each night and must

LOCATING POSITION FOR BORING HOLES be stopped at daybreak. Then a selenium cell is placed in a primary circuit. Selenium, being a poor con- ductor in the dark, keeps the circuit open until daylight comes in. Then the conductivity changes and the circuit is closed. This, by operating a relay, opens the sparking circuit. Fig. 5 is a more pattery familiar method and consists of ar- ranging a floatina UL tank so that when ABRANGEMIENT,£OR the maximum wa- SHORTS_OR GROUNDS ter level is reached the contact of a switch attached to the float arm is broken, and _ the engine is stopped. me RECEIVER

|

ol i S| Fig. 6 is a meth- aN - a od of stopping an Mt N engine from any BASEMENT _ distance which can be reached by wire- less. An aerial is connected to a re- lay and battery. In the circuit is placed a_ coherer. When the key is closed at the sending station, the coherer*is induced to close that circuit and the relay oper- ates to open the secondary circuit and the engine stops. This may be increased in efficiency according to the user’s demands. In case an electric motor is to be stopped the controller handle must be held in place by a magnet and when the magnet circuit is opened a spring pulls the motor switch back, out of contact. A Scraper Shaped to Work in Square Corners O you want to save many hours of exasperating work? Then grind at least one of your hand-scrap- ers as shown in the illustration. The blade as it comes from the factory has four straight edges. The theory is that any of the four edges may be used. This is a fact, but it is also a fact that no professional wood- worker ever uses more thin two— namely the two narrow ones—and usually he uses only one of these as soon as he has found out which is the better edge. On the other hand, the rectangular shape of the blade makes it exceedingly difficult to work into the square corners of paneling and similar places where three surfaces meet at right angles. The edge of the scraper, to work well, must have a slight curve, which makes the outer angles between the sides and By Henry Simon the cutting edge more than 90 degrees. Fer this reason alone it would not fit into the right-angle corners of the panel. But even if the cutting edge of the scraper were kept strictly square, the scraper would not work satisfac- torily in such places because even at best there is some lateral movement

SCRAPER IN A CORNER

How to shape a scraper so that it will get into square corners 92 which is very apt to cause damage to the edges of the stiles or rails if any attempt is made to work close into the corner. This is exceedingly trying, especially in particular work. Such work is in- variably glued, and some of the glue usually works out in the corners and has to be removed. Even if this is not the case, it is usually necessary to scrape good work after it is completed, in order to leave a perfect surface and remove the smudges and marks which are usually in evidence. And nothing spoils the looks of a piece of work more quickly than untidy joints. Grinding the scraper, as shown here, is the work of a few minutes, and it will then be in shape to handle corner work in a way that is a delight. The full capacity of the scraper’s blade is retained.— HENRY SIMON.

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July, 1920 «; hampion Dependable Spark Plugs 80% Tractor Equipment ORKING under full load ten to twelve hours at a stretch, the tractor gives spark CHAMPION plugs their most severe test. Champion Spark Plugs with their famous No. 3450 Insu- lator are so universally recog- nised as best adapted to the unusual conditions of shock, heat and temperature changes in tractor service that they have been chosen as factory equipment on 80% of all trac- tors being built today. There is a Champion Spark Plug specially designed for every type of gasoline engine. Order a set from your dealer now. Be sure the name Champion is on the Insulator and the World Trade Mark on the Box ‘Champion Spark Plug Company, Toledo, Ohio Champion Spark Plug Company, of Canada, Limited, Windsor, Ontario ————ooOoOoOEOeeeeeeeeeeeeeeeeeeeeeeee 93

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PEE / LTT eee peer eenieyareey i. RBS Sy ee Oe en eee ate wmerncnaens peat E “soe : 28 Published in the interest of Elec- trical Development by an Institution that will . be helped by what- ever helps the Industry. There was once a substance called coal It doesn’t take a Jules Verne to imagine the time when our present-day fuel will be gone. But there is nothing frightful in the pros- pect. Already the world’s engineering brains have cast ahead and discovered a new fuel in rain drops and dew fall—water power. Nor is this source of power a hazy dream of the future. It’s here. In California, for example, 700,000 hydro- electric horsepower are right now turning wheels, lighting cities and harvesting crops. In the United States as a whole there are 9,000,000 hydroelectric horsepower actually at work—and this is but fifteen per cent of our available supply. It is to the other eighty-five per cent we must look against the day when coal and oil are museum curiosities. Just how soon hydroelectric development will come to any community must depend on local conditions—such as how long the coal supply there can advantageously compete with water power. But in the many places where coal is scarcely to be had, sane common-sense thinking about the relative economy of water power will hasten its coming—to the common good. We should all understand that water power is not the interest of any particular business— that it 1s not a political issue, but a great eco- nomic one which affects us all. So its support must come from the people, whose money will be needed to finance it. And rightly so. Conservation of our national resources is one of the first benefits of water power develop- ment. ‘The preservation of forests, the avoid- ance of floods, the irrigation of arid lands are part and parcel of this program. ‘Truly, unharnessed water is a national pos- session which goes to waste as long as we do not use it—and in this day of inadequate pro- duction and the high cost of living, any waste is an economic crime. estern EjJecfric Company N Oo 1 1 The Western Electric branch in your e city is one of more than forty similar organizations distributing electrical products of all kinds, through retailers to the general publicand direct to industrial users. Western Electric Service is within your reach wherever you may be situated. a 4 94 Popular Science Monthly To Make a Star-Shaped Flower Bed HE outline of a flower bed has, of course, as much to do with the appearance of the flowers as the se- lection and coloring of the flowers themselves. The illustration shows how a star- shaped bed can be built and outlined Flowers growing in the frame of a flower bed gain much in beauty. Here is detailed information for making a star-shaped setting that is attractive with thirty bricks and but very little labor. Five points with six bricks to an arm give a bed of medium and attractive size for the lawn. ‘The bricks are separated a trifle and held with a mixture of cement and sand. When firmly set, the bricks should be given one or two heavy coats of white paint. The bed forms a frame for the outdoor flowers which is pretty when viewed from any angle of ap- proach.—FRANK W. BENTLEY. An Improvement on the Ford Running-Board HE appearance of a low-priced car may be greatly improved by put- ting a brass binding on the outer edge of the running-board. It is a simple thing to do. Take ordinary angle-brass with the flanges about five eighths of an inch wide, and screw it to the edge of the board, one flange flat on the board and the other vertical on the edge. Fasten it with flat-head brass screws and make the countersinks carefully so the screws will be flush and smooth. Bevel the ends to conform with the angle of the fenders. A running-board covering that looks well and will last for at least one season can Le made of strips of old heavy lino- leum turned with the wrong side up and painted with two or three coats of any desired color. If the work is carefully done the added bit of trimming will give the car a greatly improved appearance, which will more than repay fo~ the labor expended.—HOWARD GREENE. WY )))) Y i Brass binding im- proves the running- board’s appearance

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July, 1920 Hot towels and finger rubbing not needed with Palmolive Shav- ing Cream. See this for yourself. Use a trial tube free. Stop Shaving the old way There is no need to use hot towels to soften the beard. Nor to rub the beard. Nor to submit your face to a lather that dries quickly and _irri- tates the skin. Once such things were considered a necessary evilin shaving. But they are without reason to- day. For science has found a better way of preparing the beard for the razor. An easier way. And a quicker way. It lies in the use of Palmolive Shaving Cream. And to show what a big difference it makes in shaving, we are sending a trial tube free to every man who requests it. “a Within one minute the beard absorbs 15 per cent of water and the horniest be becomes wax-like. with a natural oil. : ’ Palmolive lather main- tains its creamy full- ness for 10 minutes and thus lubricates the shave. Secret of softening the beard Every hair of the beard is coated And that oil has been an obstacle in shaving. The ordinary shaving soap or cream fails to cope effectively with this oil. Thus the beard can- not absorb water enough or quickly enough to make the hair cut easily. That is why men have had to use hot towels and rub the beard with the fingers—to force moisture into the beard. Palmolive lather instantly emul- sifies the oil on the beard. Then the beard —a horny substance — quickly absorbs the water. It ab- sorbs 15 per cent of water within one minute after lathering, as proved by laboratory tests. And that makes a wiry beard wax-like. This achievement alone cost us 18 months of effort. And we tried out 130 formulas. THE PALMOLIVE COMPANY Milwaukee U. S. A. Copyright The Palmolive Co. 1920 95 Stays foamy 10 minutes Palmolive ~ makes a_ richer, creamier lather than you have ever known. And it stays moist and foamy on the face 10 minutes. You don’t have to relather. A mere bit is ample for a shave. For Palmolive multiplies itself in lather 250 times. There’s enough for 152 shaves in the regular size. A cream that is so active, you know, is something new. Palmolive is also a lotion. It contains palm and olive oils. Thus it soothes and refreshes the skin, and gives a delightful “after feel.” Try it FREE Note that we are sending atrial tube of Palmolive Shaving Cream to all men who re- quest it. There is no charge of any kind. Take ad- vantage of this free offer. Learn what it means to use a lather that instantly emulsi- fies the oll-coat on the beard. And a lather that con- tains both Palm and Olive oils. Mail coupon for free trial tube. “Let your own ex- perience reveal the wonders of Palm- olive Shaving Cream, j ‘i Send For Free Trial Tube THE PALMOLIVE COMPANY, Dept. 116, Milwaukee, U. S. A. Please send me a free trial tube of Palmolive Shaving Cream. ee | PUGCEEE i 6.0 Si vccetcck eee yee

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This is Duracord. Thick, heavy strands, woven like a piece of fire hose, not braided. Picture shows outside covering only with im- pregnating compound removed. anmeenesbemmrerameemnnar oe ee ee eh in . + ets ciememiaa ae Here is theordinary braided cable cover- ing. Note theopenand porous construction, easily cut, stretched or unraveled. Compare it with the illustration of Duracord above. The life of a Portable Electric Cord depends on its cover This outside cover determines the real strength of any portable electric cord. What’s the use of good insulation if it’s not properly protected? TURACORT) TRADE -MARK is insulated better than underwriters require- ments. In addition, it has a heavy protective covering woven like a piece of fire hose. It outwears ordinary cord many times. This cover withstands the battering, hard knocks, and abuse of everyday use. It means fewer replacements—tools and men are kept on the job. Duracord can be furnished in all sizes of portable electric cord and also in the larger sizes of single and duplex cable. Ask your electrical jobber about Duracord or let us send you samples of Duracord and ordinary cord for you to test and compare yourself. TUBULAR WOVEN FABRIC CO. Pawtucket, R. I. Makers of Duraduct Flexible Non-Metallic Conduit and tubular woven fabrics of all kinds Popular Science Monthly When the Thermometer Liquid Separates T sometimes happens that the liquid in thermometers, particularly in those not using mercury, splits up into two or more parts inside the glass. This can generally be remedied by placing the lower end of the thermom- eter and bulb in hot water, at the same time giving the instrument a slight jar. This will cause the lower end of the liquid strip to expand and connect with the broken away portions. The hot water used should not be at a higher temperature than the maximum reading of the thermometer. Winding the Wall Clock _ from the Floor SHORT time ago in a hardware store, I saw the floor manager winding a clock high up on the wall with a flexible winding rod like the one pictured. He had utilized two emergency brake rods from a Ford. One rod was cut off about a foot from a clevis and the sawed end was split up a short distance and driven over the flat clock-key handle and riveted there. The universal joint which made the rod flexible was constructed es fol- lows. A piece of round rod (metal tubing can be used instead), was fitted loosely between the jaws of the clevis of each rod. Two holes were ROUND ROD ——TLeLevis TURNING HANDLE FORCED THROUGH DETAIL OF ROUND ROD IN UNIVERSAL JOINT HANDLE” ROD SPLIT AND RIVETED OVER KEY Why climb a ladder to wind that wall clock? Do it with an extension winder drilled opposite each other near one end of the rod. Then two similar holes were drilled at right angles to them in the other end. These were tapped for machine screws. Thus the clevises to the two rods were pivoted to each end of this round rod. The clevis should turn easily about the screw with a little play if possible. The second rod can be made as Icng as necessary to reach down to the operator, depending of course upon the height of the clock from the floor. Drive a piece of rod, for « handle, through the bottom clevis on the Icng rod. By standing at a slight angle from the clock after the key is inserted in the winding hole in the clock the rod will turn easier than if operated at right angles.—L. B. ROBBINS.

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July, 1920 P WIN: CHESTER 1866 “IMn0 nen ae aa Ss ee eww LOU in at The Winchester Model 95 WHY YOUCAN TRUST YOUR WINCHESTER O matter how critical a test you may put your Winchester Rifle to, it has been put through harder ones for you before leaving the factory. The barrel must pass the Provisional Proof Test as soon as it is bored. In this it is fired with a powder charge two or three times the normal strength and a bullet one-third heavier than usual. This is to determine if the steel can stand such abuse without sign of flaw or strain. Loading, firing, and ejecting are tested just as completely. It must handle and fire standard cartridges in all positions, smoothly and rapidly, or it cannot pass. Then it is given the Definitive Proof Test, which is officially accepted by the British Government in lieu of any further test. This requires your Winchester to withstand a charge 25 to 40 per cent. more powerful than that for which it is intended. Following these many shooting tests, your rifle is taken to the range for target- ing. Here its sights are set correctly, and it is then required to meet the Winchester test for accuracy—and do it fully and regularly. The firing is at distances up to 200 yards. Having withstood all these severe tests, your Winchester Rifle then receives the ‘Winchester proof (F) mark on barrel and receiver —than which there is no higher mark in gunsmithing. How vital to you to have this Winches- ter proof mark on your rifle when a hunt- ing climax comes. To have for those few swift seconds a rifle which you know you can trust. For grizzly and Alaskan brown bears, moose, and other large game of great vitality, as well as for long-range shooting at caribou, mountain sheep and goats, above timber, we recommend the Win- chester Model 95, shown above. It is the most powerful American sporting rifle. Made in .30 Army, .303 British, .30 Gov-- . ernment, .35 Winchester, and 405 Win- chester calibers. Other Winchesters are made in abun- dance—there is a tested Winchester which you can trust for any game. For deer, we suggest the popular Model 94, of .30, .32 W. S., .32-40, or .38-55 caliber. Go to your local hardware or sporting- goods store for detailed specifications of the Winchester Rifle and Ammunition you are interested in. If you wish further information, write to us, and mention the kinds of game you intend to hunt. "WINCHESTER REPEATING ARMS CO.."~-NEW HAVEN, CONN. U.S. A. High Power Repeating Rifle

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a = NA ORE

Here’s the Soap that Gets the Dirt Just in from the work- bench- dirty with the grime of the shop: the hardest thing in all the world to wash off cleanly. That's the time you ll ap- preciate Goblin; it dissolves every particle of dirt and lathers freely in the hard- est or coldest water; does not injure the most sensitive skin, and leaves it clean and smooth. Goblin works wonders for the hardest worker. At your grocers; if he hasn't it send coupon for free trial size cake. Goblin Soap Ses a ae eee ee ee ee ee ee ee ee ee ee es es a Regular Trial Size CakeF ree! CUDAHY, Dept. K. 111 W. Monroe St., Chicago 64 Macauley Ave., Toronto, Canada Pleas: send me trial size cake of Goblin Soap.

SPACE FOR SHAFT

Popular Science Monthly A Quick Way to Babbitt By R. C. Leibe HERE are many ways and means of ‘re-lining cast-iron boxes with babbitt metal and the common ways are well known to mechanics; but herewith will be shown a new way which’ has merit in both speed and perfect fitting. The common way may be described as babbitting one-half of the bearing at a time; then by means of paste- board. liners between the _ halves, making the other half complete. This

NOTCHES IN ij): CARDBOARD 771! FiG.2. FIG.

i Ss <7 CARDBOARD LINERS

BABBITT CARDBOARD LINERS <_— ———) FIG.3

Here is a way to attain speed in bab- bitting with the assurance of a perfect fit when the bearing is tightened up method has many drawbacks, such as misfits, and a tendency to twist about. The “‘solid’”’ or double poured bear- ing is not well known to the trade but has many advantages that include good fitting qualities, solidness of bearing, and the absence of space in which the nuts shake loose. It takes half the time required to babbitt the bearings in halves. Fig. 1 is an illustration representing the bottom half or base of the bearing with a section of shafting in place, and the “‘bug’’ of the process which makes double babbitting possible. This is shown in the notched paste-board liners seen snug up against the shaft- ing. When preparing for this work, take two short leather strips just long enough for the shaft to rest snugly upon and place them in the bearing- shell—one near each end—being sure that their thickness is the same as that of the babbitt metal wanted. Next, place the shaft in bearing on these leather strips and adjust with little leather wedges. Next prepare the pasteboard liners as shown in Fig. 2, and place them on top of the bearing-half edges with notches against the shaft; place the top cap or other half of bearing in place and bolt the bearing together very tightly. Then you are ready to pour the babbitt- metal in the top oil-hole after the ends have been stopped up by means of pasteboard rings to insure smooth ends to the bearing. The arrow in Fig. 1 shows these end stop3 which are 98 secured by taking a piece of paste- board and hammering it against the end of the shaft until it is cut through, giving a tight fit to the shaft. Clay mud or soap may be used to hold this in place. When the bearing is full of babbitt- metal, break the halves apart for finishing by inserting the point of a cold-chisel in the slit between the halves, and with a hammer, striking-a few light blows. They will break apart easily as nothing. holds them but the little metal which has run through the notches in the process of reaching the bottom half of .the bear- ing. When they are thus apart, file off ragged ends of the notches even with edges of the bearing, and. after removing the notched liners, insert new liners just twice as thick, bolt up tightly again and place on the shaft. Or, if it should be a stationary shaft- ing of long length, bolt it up less tightly and there will be just enough play to avoid a tight bearing which would result in overheating. All important bearings of high-speed machines which burn out often or. are subject to hard wear, should have extra short-length shafts made at a machine shop a trifle larger in diameter, than the one on machine, for babbitting purposes alone as it will give room in the bearing for oil-film without the fatal scraping or wrapping shaft with paper for this effect. It is best not to pour hot babbitt on high-speed or important journals. Fig. 3 shows an end-view of the bearing bolted up ready to babbitt in the way described.. The arrows point to the notched liners in place. The inner circle is the shafting; the space between the shaft and the cast-iron boxing is for the babbitt. Fig. 4 shows the wrapping shaft with a cord to keep the oil in the center of the bearing. How to Anneal Aluminum without Breaking It LUMINUM sheet, like brass and copper, comes in various degrees of hardness, or temper, and the hard sheet is likely to crack if the job calls for much bending. In such a case anneal the metal by heating it in a clean fire until - ALUMINUM it has reached cL Ts a very dull red —so that the GAS Stove. “sHeeT ion ed shows only ae : when the metal Even heat is obtained is held in. the by placing the metal on a piece of sheet shadow. The iron held over the fire best way to heat a small piece of metal is to place it on ‘a piece of sheet iron held over the fire. This will make it easier to “heat uniformly, which is an important consideration.

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thly ste- the gh, lay this itt- for fa the ga eak em. run 3 of ar- file ven fter sert aft. aft- tly ’ to uld ant ich ard gth "ifle on one for or this hot ant the > in int The ace ron ord the im and ees ard alls ase na ntil hed red the nly etal the The to nall iece ‘his aly, ion. July, 1920 Radium Luminous Material UNDARK is used on numerous articles, of which the following are the most important Watches Clocks Flashlights Pull-Chain Pendants Push-Button Switches Flip Switches Door Bells House Numbers Hospital Call Bell: Ship’s Compasses Lock s Safe Combinations Names of the makers of these furnished upon request Gasoline Gauges Speedometers Steam and Pressure Gauges Revolver Sights Telephone Mouthpiece Fire Extinguishers Mine Signs : Women’s Felt Slippers Fish Bait Theatre Seat Numbers Convention Buttons Poison Indicators 0 Sees “IT want that on mine” The increased usefulness that UNDARK gives to watches it also gives to engine-room gauges. With an UNDARK dial they can be read in the darkest shadow without the aid of a light. UNDARK on the handles of electric switches prevents fatal mistakes. It makes alarm bell push-buttons always easy to find. UNDARK doesn’t get dark in the dark It contains real radium and will glow for years. You want it on safety and machinery control devices in your business. You also want UNDARK on your watch, on clocks in your home, on your motor gasoline gauge, and also on your pull-chain light pendants, electric buttons and door locks. We are miners and refiners of radium-bearing ore, the pioneer manufacturers of radium luminous material in this country and the largest in the world. Our service of instruction and inspection encourages the appli- cation of UNDARK by manufactarers in their own plants Radium Luminous Material Corporation 58 Pine Street, New York City Factories: Orange, N. J. Mines: Colorado and Utah Trade Mark Name UNDARK Reg. Applied For .

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isaac eT acasa ties wisaniDhinamaeseanlin is — 4 T takes but a moment— to mark the career of your choice, sign your name, clip out and mail. Yet that simple act has started more than two mil- lion men and women toward success. In city, town and country all over the world men are living contented lives in happy, prosperous homes —because they clipped this coupon. In every line of business and industry, in_ shops, stores, offices, factories, in mines and on _ railroads, men are holding important positions and _ receiving splendid salaries—because they clipped this coupon. You too can have the position you want in the work you like best, a salary that will give you and your family the home, the comforts, the little luxuries you would like them to have. No matter what your age, your oc- cupation, your education, or your means—you can do it! All we want is the chance to prove it. That’s fair, isn’t it? Then mark and mail this cou- pon. There’s no obligation and not a penny of cost. It’s a little thing that takes but a moment, but it’s the most important thing you can do today. Do it now! : — ee eee ee = TEAR OUT HERE cee ere oe ee eo INTERNATIONAL CORRESPONDENCE SCHOOLS ‘ BOX 7684, SCRANTON, PA. Explain, without obligating me, how I can qualify for the position, or in the sullect, before which I mark X. ELEOTRICAL ENGINEER SALESMANSHIP Eleetrie hting and Rys. ADVERTISING Electric Wiring Window Trimmer Telegraph Engineer Telephone Work MEOHANIOAL ENGINEER Show Card Writer Sign Painter |Railroad Trainman Mechanical Draftsman ILLUSTRATING Machine Shep Practice Cartooning —— er - ‘ ——- MANAGEMERT s Engine Operatin ivate Secretary CIVIL ENGINEER sa BOOKKEEPER Surveying and Mapping MINE FOREMAN or ENGR STATIONARY ENGINEER | Stenographer and Typist Cert. Pub. Accountant TRAFFIC MANAGER Marine Engineer Railway Accountant Ship Drafteman Commercial Law ARCHITECT GOOD ENGLISH Oentractor and Ballder = - Teacher Architectural Drafteman Common School Subjects Concrete Builder CIVIL SERVICE Structural Engineer Railway Mail Clerk PLUMBING AND HEATING AUTOMOBILE OPERATING Sheet Metal Worker Auto Repairing Textile Overseer or Supt. Navigation Spanish OHEMIST AGRICULTURE Freneh Mathematics Poultry Raising Italian Name. Present Occupati Street and No. City. . State. © Danddians may send this coupon to 7-268 _ Internationa} Oorrespondence Schools, Montreal, Canada Popular Science Monthly How to Make a Pair of Automatic Forceps By Frank W. Harth LLUSTRATED by the accompany- ing diagram is a device which will be found handy for picking up and holding small articles, such as screws, bolts, nuts, etc. It may be constructed from scrap material. The handle of the instrument can be made from a discarded metal pocket pencil PRONGS OF WASHER pst ~A y HANOLE B BUTTON To solder the prongs in place the plunger: rod is pushed through the tapered part until the drilled end of the rod comes outside. A wooden plug may be jammed into the cap end to hold rod in place while the prongs are being soldered. The work’ must be clean and smooth so that the rod can slide WASHER PLUNGER from which the cap and interior have been re- oo moved. A dis- — carded stilo fountain pen can also be used. It is essential, how- ever, that the business end be tapered as indicated. The plunger rod is made in accord- ance with the diameter of the handle and should be at least 3/32 in. in dia- meter. The length of the plunger rod should be approximately as shown. The plunger button can be either metal or composition. It should be securely fastened to the plunger rod, by a screw if composition, and by riveting if metal. The forceps prongs must receive careful attention as the proper work- ing of the instrument depends on them. Spring steel wire about No. 20 gage will prove the most satisfactory. The wire must be stiff and well tem- pered. The wires are soldered into a previously drilled hole in the end of the plunger rod, the soldering being done when assembling the instrument. The wires should be spread so that they have the appearance shown. The prongs can be of various shapes depending on the commodity to be picked up. The shape illustrated is a good one for general purposes and can be obtained by careful flattening with a hammer. The spring is made adaptable to the bore of the handle shell and should be strong in its action. Its location is shown between washers A and B. Washer A must fit the bore of the handle shell snugly and is rammed tightly into the tapered end. The hole in the washer should be large enough to permit the plunger to slide through easily. Washer B is the same as washer A in a general way, with the exception that -its outside diameter is a little less than the inside diameter of the handle shell so that it will slide up and down without bind- ing. The hole through the washer must be the proper size so that when the washer is slipped over the plunger rod it will fit tightly. A small amount of solder will hold it securely. The different parts are now ready for assembling. This is simpler than would at first seem apparent. The spring is dropped into place at the cap end and the plunger rod inserted. 100 The illustration of the forceps shows construction, and also the instrument picking up an olive back again with- out binding. The cap may then be putinplace. If it is of the thread- ed variety the problem is very simple, but if it is not, a cap must be made from tubing and a washer and soldered into place. The hole through the cap must be large enough to enable the plunger to slide easily. The plunger button is then fastened in position and the instrument is ready for use. The instrument is simple to use. The button is pressed down and the spread prongs placed over the object to be picked up. As the button is released the plunger is forced up by the spring and the prong wires, being drawn up in the shell of the handle, come together and firmly take hold. To release the object the button is simply pushed down. Three or more prongs can be used, depending on the thing usually han- dled. For precious stones a three prong instrument is desirable. The instrument can also be used for removing the illusive olives from the long and narrow bottles in which they are confined. THREE PRONGS FOR PRECIOUS STONES, ETC. OLIVES The Curling-Iron as a Kitchen Utensil HE other day my grocer failed to send the wire key which always accompanies a can of sardines. My guests had already arrived so a sub- stitute had to be found immediately. There happened to be an old curling- iron in my bureau drawer so I used was lost. luncheon was not de- layed. The can was opened with the aid of an old hair curling iron which quickly removed the tir cover that instead of telephoning for a key. It not only served the purpose, but did the work better than a key does it.— MINNIE ALICE OSBERG.

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July, 1920 Man alive— Listen! You can smoke Camels till the cows come home, without tiring your taste! AMELS bring to you every joy you ever looked for in a cigarette! They are sO new to your taste, so delightful in their mellow mildness and flavor, and so refreshing, you will marvel. that so. much enjoyment could be put into a —cigarette! . : To the most fastidious smoker; Camels are a-revelation! Camels quality is as unusual. as Camels expert blend of choice Turkish and choice Domestic tobaccos which you will prefer to either kind of tobacco smoked straight! No matter how liber- ally you smoke, Camels never will tire your taste! You will marvel at Camels smooth = “body”. And, your delight will also be — keen when you realize Camels leave no unpleasant cigaretty aftertaste nor un- pleasant cigaretty odor! For your own personal proof, compare Camels with any cigarette in the world at any price. Camels are sold everywhere in scientifically sealed packages of 20 cigarettes for 20 cents; or ten packages (200 cigarettes) in a Classine-paper-covered carton. We strongly recommend this carton for the home or office supply or when you travel. R. J. REYNOLDS TOBACCO CO. Winston-Salem, N. C. 101

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The Work Behind The Service Owing to international conditions, the Bell Telephone System was for two years unable to secure raw materials and equipment. While supplies were thus shut off demands for service increased beyond all precedent. When the opportunity came to go forward the system faced the greatest construction problem of its history. It has gone forward with a speed and certainty that is bringing nation-wide results. New exchange buildings, perma- nent brick, stone and steel structures, have been erected in many cities; scores of central office buildings have been enlarged; additional switch- boards are being installed in all parts

One Policy of the country; new conduits built; hundreds of thousands of miles of wire added to the Bell service; more than a million new telephone stations installed; and expansion giving a wider range of operation has been ceaselessly advanced. As the wheat crop gives no bread until after the harvest and milling so you will not have the full fruition of our efforts until construction is complete. But, a big part of the work is accomplished; the long hard road travelled makes the rest of the un- dertaking comparatively easy. It is now but a matter of a reasonable time before pre-war excellence of service will again be a reality. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES Ore System Unwersal Service

You Gan KNOW all about AUTOS, TRACTORS, AEROPLANES, STARTING and LIGHTING SYSTEMS, STORAGE BAT- TERIES, VULCANIZING, etc. Valuable Book FREE **How to Succeed in the Automobile, Tractor and Aeroplane Business,”’ gives much new and very useful information; also tells all about the many splendid advantages and practical training vou can a get at thiscollege in a few weeks. Tear this out and write fora copy, FREK, today. aiaameknaas OF AUTOMOTIVE ENGINEERING Dept.57 1519 S. Wabash Ave. | (O11 LO7-VC Te)

WANTED Representatives in Every Factory Popalar Science Monthly keeps abreast of the times in new inventions und discoveries. Many of the best ideas come from the skilled work- men in the factory. We want representatives 'nuvery factory to keep on the alert for newideas and to collect new and renewal subscriptions. Your spare time is easily worth $10 to $25 a week. Popular Sclence Monthly, -225W 39th St., New York

‘s Mining Engineer A great profession not overcrowded. The Michigan College of Mines est 1880) 'ocated in the heart of one of the greatest copp*t mning districts of the world offers a unique ‘ombination of thee - oretical instruction with’practicai experience in @ four year course whith can be completed in three calendar years. Its breadth affords foundation for expert specialization in that field cf engineering which most appeals to the studenc Great mines, mille, smelters, electrolytic and power plants are practically a» part of ‘the college ‘equipment and constitute a factor of enormous value in the course of instruction. Managers of large operations regu- ~larly lecture to Classes. Region aftords unusual opportunities for geological study. Nine buildings, dvanced ‘Methods. Vigorous Athletics, Bowling, Billiards, Tobogganing. ‘‘*M.C.M Men Make ‘ For descriptive book address 262'College Ave., Houghton, Mich. Te Michigan. “<f* Mines 102

Popular Science Monthly Obtaining Speed in a Machine Shop ATHER a complicated piece of work for a thirty-three-seconds’ job is shown in the accompanying | illustration. It was done in this time, however, and two of the pieces were made in double this time. Many others were made continu- ously on sched- ule time. It is wonderful, when you stop to think of it, and yet it is not an unusual thing in some shops. The work is all done by a single ma- chine, and done automatically, including the turning, the boring, the counterboring, reaming, facing, necking and threading. The operations are completed prac- tically at the same time. There is no pause, no let up, while the machine turns out the work, moving with the regularity of a swinging pendulum. Other styles of work, equally com- plicated, can be turned out with equal ease and at very great speed. Some of the big machine companies of the country make special studies of any particular work of this nature which you may wish done automatically. After the study has been made and reported on, a special machine is de- signed to take care of the several operations involved.-—H. C. RIDGELY.

This complicated piece of work, including the turning, boring, counrer boring, facing and threading, was com- pleted in just 33 seccads Control the Lighting Switch through the Window HE underwriters’ rules now re- quire a lighting switch, and further that it be on the outside of the building. Opening and shutting the window every time I used my set was some trouble, so I devised the follow- ing switch and found it very satisfac- tory. The diagram shows that it is BLADE P CLIP

With this device you can either turn the switch on or off from outside the window

nothing more than two posts, each hav- ing a clip, mounted upon a base, also a

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July, 1920 blade and its clip mounted on the center of same. A rod was attached to the end of the blade as follows: After’a slit was cut between the hole and the end, a screw-eye was inserted and the slit nailed together; then the screw-eye was screwed into the rod. It wasthen nailed to the window-sill and the rod running through a window- pane. To make the hole in the window- Fast-Cutting pane, first place a little mound of clay Mineral Abrasives on the glass and make a hole in it, then Onclothand paper: pour molten lead into it, thus melting a Flint Paper hole through the glass. Following the same principle, I made another hole for a porcelain tube inserted for the purpose of carrying the wire from the switch to the set.—R. J. HAGERTY. Use Tracing Cloth to Focus Your Camera VERY photographer knows that the only sure way of focusing a picture is by using a ground glass. All other methods are more or less guess work, particularly when the | details of an object. are to be clearly shown. This can be done with the usual type of plate camera but not with the small swing Instead of a ground glass you can use a piece of tracing-cloth to focus your camera, if it does not use roll film back type of hand camera such as shown in the illustra- tion. It was to enable the owner of such a small camera to focus it accur- ately that the screen shown in the diagram was designed. Note the rhree conven- ient rolls of United States Abrasives on the lathe. No waste here. Sand Paper is Buy it as you would a tool —instead of just asking for ‘‘some sand paper’’. Buy the U.S. map brand that stays sharp-—for every little particle of flint or garnet is a sharp- edged tool, glued everlastingly to strong cloth or tough-fibred paper especially made for the purpose. United States Sand Paper is known everywhere by the map trademark. U.S. flintand garnet (the semi-precious gem) are first choice in the wood working industry where it is used in shéets, endless belts, discs and wasteless rolls Garnet Paper Garnet Cloth Emery Paper Emery Cloth Crocus Cloth Carbalox Cloth Herculundum Cloth Sheets, Discs, Circles, Belts and Rolls of various widths and lenyths of the above U. 8. Abrasives. a Tool the electric furnace, are time and labor savers— Herculun- dum for cast iron and similar materials; Carbalox for steel, brass, copper, aluminum, etc. We would welcome an oppor- tunity to discuss this with you. From the crushing of the materials to the last coat of glue, U.S. Sand Paper is sur-. rounded with almost unbeliev- able precautions to insure uniformity of quality. You cannot sharpen sand paper: therefore buy the best, the U. S. brand—because it stays with you until the job 1 In this case draftsman’s tracing- of convenient widths. = oe - pag hose nage ‘ cloth which is semi-transparent was ss not have U.S. Abrasives in : used but oil paper or a similar trans- For finishing metalsurfaces stock, write direct to us. Our ; parent material can be just as satis- in foundries and machine Service Department will factorily employed. shops, discs and belts of Her- recommend the one best grade 4 _ Make a mat of cardboard, the out- culundum and Carbalox from for your particular work. 3 side dimensions of which will fit snugly into the cam- era back. The UNITED STATES SAND PAPER COMPANY, Williamsport, Pa. cra , Vy CMY YYyH Stocks at following Branch Offices: insideopening V/ UY New York Philadelphia Chicago Boston Detroit San Francisco of the mat is UH, TRACING CLOTH Y 7 made the y OR OILED PAPER ///] same size as yy y) the finished Wo. yyy negat iv e Herculundum and Carbalox discs cemente 4 ° ar : ed to horizontalor vertical wheelsare great Pastethecloth = \_caeogoneo mar tgs to's cove at The alec, ict lone or paper over _ . both cloth and grit being just right for the the mat as in- The tracing-cloth is work at hand. oT he table grinder below dicated . and set it in the simply pasted over the mat and fitted snug- ly into the camera is a money-maker. Get the complete story on this, camera. A clip of paper will hold the mat firmly in place.—FRANK W. HARTH. | Light the Inside of Your a Touring Car High speed endless cloth belts of sand paper are necessary in every modern woodworking plant. U.S. sand belts last | aa IMOUSINES have inside illumi- long. Ifyou have any sanding probleme nation. Why not have a light. ; omy cane as well as how to make it. af inside a touring car?- There are many. | ay a ty) occasions when a light would be a great convenience for those getting in 108

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Swimming ’nEverything ,. =~... The old swimming hole—with its shady banks, its cool, clear water, and its smooth, sandy bot- tom—calls you! Wherever and whenever you choose to go, your bicycle will take you—quickly and easily. Use- ful for pleasure—useful for business—always Cycle Dept., THE DAVIS SEWING MACHINE CO., Dayton, Ohio - with our reputation. ready! What weuld a fellow do without a good bicycle? Ir you're at all particular, you will want a Dayton B1- cycle--a leader for 25 years--noted for its beauty, Comfort, speed and long-life. Write today for your dealer’s name,and catalog No. 44, showing 8 finenew 1920 Davton models, for men, women, boysand girls, / Garter Kew Gif | For more than forty years Boston Garter ff has been a friend to men the world over. It not only keeps the old but makes }} Many new ones each year. Most men ask $ for Boston Garter as a matter of course y) —the two words go so well together. Big Profits in ) Vulcanizing j Little Capital Needed ") Let us help you start in this profitable business and be independent. Many of our graduates make $3,000 a year and over. We manufacture the Ander- son steam vulcanizer and the Anderson re-treader and teach you the Famous’ Anderson Method of vulcanizing. With an Anderson you can get the cream of the business regardless of competition, because you can guarantee the work to outlast the remainder of the tire. We can show you that the Anderson machine and method does superior work at a cost of less than 10 per cent of that required for all other vulcanizers. This means satisfied customers and bigger profits. We have established Anderson vulcanizing schools in thirty states for teaching the Anderson Method. The course requires 5 to 10 days and costs $35. If you buy an Anderson vulcanizer we not only return your $35 but pay you $5 per day expense money while you are learning. We expect Anderson vulcanizers to do first class work and expect our students to make good in a business way. Their success is our success. Therefore we do not sell an Anderson vulcanizer to any one who has not received our course of instructions. It costs you nothing to investigate this wanted oppor- tunity. Write today for full particulars and address of en school nearest you. Print your name to mistakes. ANDERSON STEAM VULCANIZER CO. Popular Science Monthly or out, and at times it may be a necessity. A small light can be easily installed as the accompanying sketch illustrates. It especially adapts itself LAMP~ CORD NN N N N f \ AA | | } ' | | | 1 How many times have you lost articles in that dark tonneau? Make a dome light for your car top as here described to being fastened to one of the bows of the top. Screwa porcelain socket for abattery lamp to the under surface of this bow, and in the middle. Use about a six- volt lamp of as large candle power as practical and connect it to the mag- neto in the manner shown. Then cut out a piece of stiff metal and bend it to straddle the light with- out quite touching it. Cut as large a hole in the middle as is required to let the light through. To Make a Space-Saving Cupboard 5 i Utilize that waste space beneath the chimney by making a closet to fit into it N many kitchens the chimney is not built up from the ground but is supported by a bracket strongly built against the wall. The triangu- lar space under the shelf can be util- ized as a cupboard for keeping cloths and brushes for use about the stove. The cupboard is hinged at the bottom and tilts out with a turned wooden knob which embodies a spring catch that locks it in position. Any ama- teur carpenter can easily construct it 13 Williams Building Indianapolis, Indiana — 104 from waste pieces of wood.

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July, 1920 A Simply Constructed Plate- Holder for Loose Films T often happens that one has a few unexposed films in a pack which, under ordinary circumstances, would be thrown away, since they can not be placed in the camera. A special holder for such films can be easily made. It consists of a piece of tin—the back of a film-pack TIN BENT OVER holder will (cess eSSeeae a serve this pur- pose. This is cut 14 in. larger than the film. The two long sides are bent backwards % in. on each side

| MUTI to make it mere . rigid. The two The metal film-holder short sides are st Suggests a way to, use each bent for- would otherwise be ward )4 in. discarded as of nouse leaving it slightly loose so that the film can be easily run under these folds without scratching. The film, re-enforced with this tin back, can now be placed in an ordinary plate-holder like any other unexposed negative.—E. BADE.

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Preventing Matches from Getting Wet AVE you ever gone camping, and tried to light a fire with matches that had become damp? Of course you have, and from experience you know that it can’t be done. Then why not waterproof your matches so that rain or water cannot injure their firing abilities? Here is the way to doit: - Melt some paraffin in a pan and dip the match head into it. The paraffin makes a waterproof coating over the head of the match and ren- ders it impervious to dampness. To Remove the Nut from a Broken Bolt HEN the end of a bolt or stud breaks off at the nut and you have no other nuts of that size handy, the broken piece can be removed and the nut recov- ered for use by the method shown in the illustration. Take two pieces of scrap steel slightly smaller than the diameter of the bolt and clamp the broken stud Removing broken bolts between them from nuts is easy pro- in the jaws of vided you clamp them avise. Thenut im @ vise as shown above can then be turned off with an ordinary wrench or spanner. VISE JAWS

BROKEN

PIECES OF STEEL

oo fe seat 3 Se

The standard shoes for tennis, boating, and vacation wear. - Made of light : anvas, in highor low models. Sturdy sport shoes—with or without heels. Made of heavy white or brown duck. Brown leather trimmings with ankle patch. One of the smart specialty pes—made of the jinest white canvas with all the style of Shoes for = sisse2=4 every summer need Footwear that combines comfort, style and economy © matter where you go this sum- mer you will see Keds. These light fabric shoes are made of With these additions, Keds have become a complete line of canvas summer shoes, Last year millions of pairs were worn by

finely woven canvas—so cool and flexible that they are always comfortable in the hottest weather. Their springy rubber soles make them a delight to wear. Some of the newer models are made just like leather shoes, with regular welt construction soles and firmly boxed toes. They are just the shoes you need with your white flannels, or for business wear in warm weather.

<0 CATE oY, United States Rubber Company 105 men, women and children. Good dealers everywhere carry Keds. Try on the different models. See how light they feel, and how perfectly they fit. Keds are made only by the United States Rubber Company. Look for the name Keds on the sole. For men and women, $1.50—$7.00 For children I.1§S— 4.50 Keds ' }

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Do RO TRA Rg TE ri Tae aa a aR cae nS oe Be an American Ship Captain Here’s the sport for spring and summer—fine steel boats just like the real ones, that are driven through the water by powerful long- running motors and _ fine screw propellers. There are beautifully painted merchant marine steainships (the Hog Island type), ocean liners, tugs, yachts, launches, swift de- stroyers, scout patrol boats and real submarines that dive. These boats are, with- out a question, the finest toy boats that run by real machinery. The boats shown in the illustration are Ives. [Ives Toys Make Hap sys Think of the fun you can have with Ives boats—a whole fleet of them. You can have har- bors, docks, wharves and freight sheds, at the seashore or beside some pond or brook. You can learn the great game of trans- portation, sending your cargoes to different ports. Get this book Write today for our fine book, “Shipsand Shipping.”’ It tellsall about the sea, its rules and regulations, the parts of a ship, nautical terms, sig- nals, etc. Send four cents to pay postage and pack- ing and write your name and address plainly. The Ives Mfg. Corporation 191 Holland Avenue Popular Science Monthly A Wooden Pedestal for a Bench Machine By H. H. Parker SMALL bench drill-press, or sim- ‘\ ilar machine, could frequently be accommodated to better advantage somewhere else than on the bench. At the same time a regular floor type machine would be too expensive. The illustration shows the construction of a wooden pedestal which is neat in appearance, heavy and_sub- stantial and requires little floor space. Standing on the floor, it supports a power driven lever feed “bench” drill-press. The top is made of a heavy plank, between 2 and 3 in. in thickness... Its length and width depend upon the size and shape of the ma- chine base, the weight of All the corners are rounded as shown in the plan sectional view, to correspond with the rounded corners _of the top piece, and the vertical cor- ‘ner timbers are set in far enough to allow the side planking to narrow in about 1 in. all around from the top plank. This, together with the base- ' board, makes a very neat finish. One side is cut away enough to allow a drawer to be fitted; this slides on two strips nailed to the cor- ner posts and is convenient for holding drills, wrenches. and other small parts. Four iron angle brackets are screwed or bolted at the corners of the wide faces as shown; these are drilled for the machine and its height lag screws or bolts to bolt from the floor, but these dimensions should be kept as small as possible, while consistent with stability. Four heavy vertical tim- bers about 4 by 4 are fast- the machine securely to the floor. If there is any concrete handy, some may be poured into the pedestal,—enough to be almost even with the ened to the top piece by means of long drift bolts 4 iB bottom of the drawer; this will add weight and cause driven into them and rivet- ed over clinch rings set in flush with the surface. The corners of the top plank are rounded off and the ends tus % sandpapered smooth. Then the ped- estal is planked up with % or 1 in. boards, the grain running horizon- tally and two or more widths used, as required. Screws, countersunk and covered by wood plugs, or nails with heads driven in and puttied over, are used as fastenings. A _ thicker board around the base, say 14 in. stock, adds greatly to the appearance of the finished article. This wooden machine pedestal is neat, and cheap. but little floor space the machine to operate with more steadiness and less vibration. While an ad- vantage, the use of con- crete is not necessary and if it is omitted there will be extra storage space left underneath the drawer. A couple of coats of dark paint, preferably the same color as_ the machine itself, will finish the work after all nail holes and cracks are puttied, and one will have practically as good a mounting for his bench machine as if it were of the regular floor pattern. It takes To Make an Electric Cigar Lighter By Thomas W. Benson HE cigar lighter described works on the principle of an arc, differ- ing from the usual type in is mounted on a strip of brass by bind- ing tightly with fine copper wire. The brass strip is fitted with a which a coil of wire is heated to the glowing point. - short length of fibre rod to ie act as a push button, the Referring to the large il- lustration the body of the — lighter will be seen. It con- sists of a fibre shell. taken from a large cartridge fuse. Holes are drilled in the brass caps, one to pass the LAMP BANK LIGHTER CONNECTED To LIGHTING CIRCUIT strip then being mounted as - shown. The other lead is connected to this brass strip. A narrow strip of friction tape may be wrapped around the casing over the live parts to prevent the leads and the other to per- mit the insertion of the tip of the cigar or cigarette. A mul 6V. BATTERY REACTANCE COIL hand touching them. The lighter may then be connected in series with a piece of carbon shaped as shown is mounted near the eud having the large hole, by means of a small bolt, one lead being fastened un- der. the head of this bolt. LIGHTER ON STORAGE BATTERY bank of lamps and operated from the lighting current. It may be used on storage batteries by connecting a mrs ieptial sy bare A gay +2 gas lighting coil in| series is connected up in either With it. Simpljy pressing the The other ¢arbon contact of two ways shown above button operates the lighter. 106

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July, 1920 i ooo met HEHLUASSUNUONYONDHRLELDSONSAADUUE UNAM NHOIOROYOSUGEOSASUNNDICPEOOOSBSOUOOEEUEOTESSQMMSDEOTASOUOSOASSUSUOIEGN PORN ATEN : YANG VANS) Neff gM OS eee OO EE or 6 ee CO ee PAT eee eS) NV TKS ne OTETR TTT TET TET 1E \O7/ GASTRASQUATRGSAGUEDADOSADRRUAOSDSUDDISESANED DIAN anegooagaNsasasaN 7 ZX TION 4S) 1 7 CO We Lyf LZ ZX WX LOTT ¢? 7. BX N/E ‘e 2) ANSVAN WANG K WN ANZ NW il UU ET LZ NK KK YEMEN TEN ne V ANG 71 Wy; W iNOSZAN FZ VEZ LZ (s } 1. N +S NW TR WY WAN NK? SS ee ee ee Ue rr NZ } = = = = — = = = — — — = — = = i = — = ~ = — = i = —~ — = = = = J = — = —~ = = = = — = = —~ — — = —~ — = —~ = — = = = = = = = — — = — = — = = = = — = = 7 = i = — = = ~ — — — i = — = = — = = — = = — = — 4 = = — = = rc = J = — = = = = — —~ = = = —~ = = — = = — = J —~ = — = — — — — = = — — — J = = — = —~ = a — = = s = = — = 4 = —~ = = = = = — = — ~ = = = = = — = i — = = = = AN ZAN LZ ? iK EL NE SVE WV. PUSDDSUSUANASASNNSDINONDT IN N SE 9.190 SE 0) 0 90 a 010 9) 1. SH g 0/7 i iS I BTR “Z WS M7 x SSO nn 6 0010 | 2 SN W772 3 LK) WZ *. e) KC SK ae js

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i EVEREADY | DAY LO} “Don’t! without Daylo’’ EMEMBER the Broad Street fire which destroyed a city block because a man carried an exposed light into the cellar? Then there was that disaster at sea that cost scores of lives; and the gas explosion which made hundreds homeless. These and many other similar catastrophies should and could have been avoided by using a Daylo. What do you think is the best use for Daylo? Your thought may win you $3000.00—$1000.00—$500.00 or one of the 101 other cash prizes of the Eveready Daylo $10,000.00 Cash Prize Contest Dealers everywhere are displaying a remarkable picture in their windows. See it. Study it. Get a free Contest Blank from the Daylo dealer and send in your answer. There’s no cost or obligation. If two or more contestants submit the identical answer selected by the judges for a prize, the full amount of the prize will be paid to each. Contest closes August 1, 1920. The Art Editors of “Life” will judge the answers. AMERICAN EVER READY WORKS of National Carbon Company, Inc. LONG ISLAND CITY, NEW YORK This sign on Daylo Dealer’s windows identifies dealers showing f the $10,000.00 Contest Picture UNE ST ic BATTERIES MAZDA BULBS contest! © > ‘10000“In Cash Prizes Metal Workers This Means Money to You The New Metal Worker Pattern Book—The most com- plete book on metal pattern work published. It con- tains 259 problems, 544 pages, size 10x13 inches. No one in the sheet metal trade can afford to be without this book. The major portion is taken up with “* Pattern Problems,” and is divided into four parts. The first part has to do with rallel forms or miter cutting, and also has many problems « the cornice maker and those who make pipe work. In the second section, on regular tapering forms, there is a diversified number of problems dealing with such objects as funnels, scale scoops, tapering elbows, roof flanges and on. In the’ third section the science of triangulation is thoroughly expounded, for within the category of irregular forms will be found more objects made of sheet metal than are grouped in the other two classes—parallel or tape:irg forms’combined. In this section on the developing of the pat- terns by triangulation so many kinds of articles are treated that a complete mastery is assured to those who diligently apply themselves to’its study. The solution of every problem that is likely to come up in practice is given. The fourth section gives the trade the benefit of the short cut methods developed by experts during the past few years. This one section with its new problems on the develop- ment of such modern work as automobile bodies, hoods, fenders. ‘mud guards, etc.; marquees. grain chutes. dust separators. ‘conveyors, d work, furnace fittings. flanges for flag poles, boxes, blower connections. range: canopies, ppers. spouts, etc.. is well worth the price of the book to those who have the former editions. Price, postpaid. $7.50. ° POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City THE 1920 Motor Annual of the Popular Science Monthly This big book accurately pic- tures and describes more than 400 new devices and accessories and contains scores of practical ideas for the Owner, Manufac- turer, Dealer and Mechanic. Everyone interested in auto- mobiles will want this big Motor Annual. The 1920 edition is limited to 100,000 copies. Order now if you wish to make sure of getting a copy. Price, postpaid, 35 cents Popular Science Monthly, 225 West 39th Street, New York 108 Popular Science Monthly A Bench Anvil Made from a Flatiron N old flatiron can be made to serve a good purpose by its con- version into a small bench anvil. A way to do this is shown’in Fig. 1. The handle is sawed off and the top Pn nds gg Fig. 1 shows how the flatiron is cut off, Fig. 2 the way it is secured to the back, and Fig. 3 its top surface ready for work surface smoothed off in a lathe or grinder. A hole may be drilled up through the bottom and tapped for a bolt to hold the casting against the lathe face plate during the facing off pro- cess. This forms an anvil with great stability and no other base is neces- sary: it is merely placed on the bench. In Fig. 2 and Fig. 3 the bottom sur- face is used to hammer on and the top is drilled and tapped, after cutting off the handle, for two °% in. cap screws. A hardwood biock is drilled and coun- terbored for these bolts and for wash- ers under their heads; by means of a socket wrench the anvil is_ bolted firmly to the base, providing a larger hammering surface than the method of Fig. 1. In drilling and facing off cast iron of this nature, care should be used, as sometimes there are encountered hard spots which would burn the drill or the lathe tool if too high a speed was used in driving the drill or the work. Here’s a Way to Utilize Qdd Cuff-Links HEN a single button of a cuff link is lost the set becomes practically useless. The accompany- ing illustration shows a method by which the two parts of the re- maining cuff button can be LINK PINNED TO SOFT CUFF used again. FIG.3. Solder a dim- = inutive safety- 5. 2. pin on the back SOLDER of each part as in Fig. 1, but FIG@| don’t solder the Don’t throw away spring of ‘the that odd cuff link. pring Solder a safety-pin pin.—J AMES to it’ and turn M. KANE. it into: a pair ry , gy oe 2 a a?

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July, 1920 The Yndian Side Car provides the utmost in comfort Every refinement of the chassis -naker’s art has been combined with Indian thoroughness and mechani- cal mastery to produce the Indian Side Car. Each detail from the all-important spring equipment down to the fold- ing foot-rest, is expressive of plan and workmanship that produces only the best. And in the design and de- velopment of each one of these details, ideal comfort for the pass- enger was the guiding principle. The Indian Side Car is worthy of the splendid road-companionship of the Indian Powerplus. In point of comfort, appearance and roadability, the Indian Side Car, like its powerful comrade, holds a unique place in the automotive field—a place it has won with service- tested merit. Distinctive Fudan features Deep, luxurious, upholstery—two-piece, sheet-metal sections—four sets of resilient springs of chrome silico manganese steel— improved ball bearing hub construction— new clamping attachments for securing wheel spindle—four-point attachment to motorcycle—tool well, floor mat, water- proof apron, self-locking door—these are some of the unusual features of the pre- eminent Indian Side Car. Department 38 HENDEE MANUFACTURING COMPANY, Springfield, Mass. The Largest Motorcycle Manufacturer in the World

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Popular Science Monthly How to Make a Jazzolin from a Broomstick fp instrument is a source of great amusement to the music lover and is one that can be easily played by anyone as it embodies only one string. Frets or marks may be made at the proper intervals on the fingerboard to guide the novice in placing his fingers. They may be copied from those on a Designed Right---Built Right The superiority of the MORROW coaster brake is the natural result of proved correctness of its design. Its —— longer life, positive a¢tion, and un- failing dependability result from the 7 easons logical application of known and mine tested mechanical principles. Orrow. Here is the way the jazzolin will Braki tface 6 3-10 in bs spare whee Reman Anyane : cs - an rekon. can play it with but little practice 2 fog by two wedges at each end guitar or mandolin or made by finding Se the scale on the instrument itself tion over entire inner hub surface. > STUR DY, SURE ; sisen: eetiniahabenatti’ The body consists of a small-sized 3 erthan hard steel inner surface, cigar box, the front cover cut as shown COASTER BRAKE ehh in the Hustration measuring 134 in ‘ or forward pedaling, the Mor- ? > 4 i The MORROW has a straight hub. Thebrake i. Dosen nalirsssges from each corner and 2) in. down drum expands against satiny deren tn- chp ean on the sides. ore ball-bearin othe ° ner surface of the hub bringing into play 6 3-10 D Gaueamraorany. The sound holes are shaped like the square inches of braking surface—larger than 6 The, Morrow is strong and “ah age —_ = i. that of any other coaster brake. The brake shoes em ree ee ole may be substituted, the Jen on the drum are of bronze and they press against J 4 ~eso meM » noggin being 3 in., the width 3/16 _in. on one _ steel—thus utilizing the difference in hardness ing perfect service. end and widening _to 3/8 in. on the of thetwometals to increase the braking power. other Set them mn or on an angle as shown, 114 in. in on front and 1 in. 31 ball bearings reduce friétion to the mini- on the back. The side view gives the mum, insuring easy coasting and longer life. position of the inside blocks—front and back—that in front being 114 by ECLIPSE MACHINE COMPANY 114 by 24 in. while the back one is 4% ELMIRA, NEW YORK by 4% by 134in. The height will vary according to the depth of the box. Demand the MORROW on the next Bicycle you Buy Bevel the top of the front block 1 of an in. to form the slant for the resem 2 = ‘ fingerboard. Bore holes in the back Do Y Work i Fact ? | cake Mieeeties er oely cote casate dateel tng | Of = block for the button peg. o ou or in a ac ory 2 estate agents operators, builders, contractors and businessmen. This ° ° $10 to $25 a Week Sor an Hour a Day Look ict deat heshn ehine asioe ae | Clamp the broom handle in a vise and aive,Fant a representative in every factory in the United gis ever gathered together on this vial subject, ‘Cloth, O56 pages. plane off the top until the width is a tes. ou can easily earn to extra each wee y ° ° * ° . 1 s N e using an hour a day of your spare time. Write to-day giving ° trifle over % in. Ow measure in the name of the factory where you are employed. Book Dept., Popular Science Monthly 4 in. on one en d, and down \% in. from Popular Science Monthly 225 West 39th Street, New York 225 West 39th Street New York the top of the end Saw on this line bp Ye to the 4 in. mark, cutting out with a AGENT oe fret saw. The length of the whole will be 15 in. Now measure in 134 in. Gold and Silver Sign Letters from the other end and drill holes For store fronts, office windows and glass ¥4, in. the depth of the handle, 7/ 16 in. signs of all kinds. No experience necessary. | wide and 114 in. long. A small strip Anyone can put them on and make money right from the’ start. of bone is fastened upon this end as 00 00 ¥ | well as one on the back of the box. $40." t od $100.2 a Week! These should have small grooves filed Near) over the country, There is a big demand in the center of the top for the string. . \. (Wr yes p> au) for free samples and particulars, | The key is made from hardwood and 4+-* if ig a E Liberal Offer to General Agents. | must taper like a violin key. The | PSP) METALLIC LETTER CO. | design may be varied to suit the , Wa 493A Worth Clerk Street, CHICAGO, ILL. | ideas of the builder. 110

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Ooo O&O wm Ss Y _ © Tm Ss Sons @ oN spree 1e 1X. 1g. , nd he he July, 1920 The design on the end is made with a three-cornered file and a small drill. The bridge is 1 in. in height and 114 in. wide. Cutin in. on the bottom to form the feet. Taper the thickness of the height from 3/16 in. to \% in. Make a small peg and insert it in the rear block. Glue strips on the top inside edges and after fastening the fingerboard through the front block set in the top and glue it se- curely. Now bore a hole through the top of the fingerboard into the block, and countersink the screw which holds it. If desired the bridge may be rounded slightly on top while the two pegs are made for the front and back. This will allow the use of two strings tuned in fifths or five tones between their pitches, preferably EH and A violin strings. Use only silk or gut strings as a steel string will sound much too tinny. Cut the grooves for the strings about 3/8 in. deep—if more than one is to be used. This will allow plenty of drop for the bow. Purchase a cheap bow from some music store or pawn shop but be sure BROOM HANDLE SOUND K 4], BLOCK i | BRIDGE i BONE - BUTTON The diagram above sets forth in detail every part of the construc- tion and you should encounter no difficulty in making the instrument that the hair is in good condition, and it should be kept well rosined. Deco- rate the edges and corners of the in- strument with narrow strips of colored paper and give it two coats of white shellac, rubbing down the finger- board after each coat. For a more finished instrument a hole can be bored in the back block under the peg, and in it a round stick about 25 in. in length may be inserted to give a substantial rest for the instru- ment. When finished this way it re- senibles the ’cello. The jazzolin somewhat resembles the ukelele except for the fact that it is played with a violin bow instead of a pick. Several of these instruments -in conjunction with a piano will render very pleasing music. The popular ‘jazz’ music becomes easy, once one is accustomed to using the bow.— FRANK W. VROOM. July, 1920 Tom Cooper enrolls in the Rahe Auto & Tractor School, in the best equipped shops ever used for training pur- poses. Learns first handall about ignition starti d Studies au- tomobiles in all their parts under Master Mechanic In- structors. | How Tom Cooper Won Out - OM COOPER lived in a small town. * He had tried several jobs, but none of them suited him. One day he read about the great Rahe Auto & Tractor School in Kansas City where any man from 16 years up, could learn the Auto and Tractor Business in 6 to 8 weeks. Over 80,000 men, thousands of them of Tom’s own age and station in life were Rahe trained men, and numbered among the biggest and most successful men in the Automo- tive Industry. They were making good, they had ' found success. Tom began to think. ‘If I stay here, what will I be earning 5 years from now?’ he asked himself. “‘And how much money will I be T getting if I go to the Rahe School and become an ) expert on autos, tractors and aviation?” He took a fas; * 00 Teper caper reveNmeTey yrs ra train for Kansas City. ] CHAPTER 2. y fi: 5 & The very day he arrived Tom Cooper enrolled asa P "| student in the Rahe Auto and Tractor School. He foun‘ he had no dull books to wade through. He set ‘a to work at once in modern machine shops that were to be his school rooms. His instructors were wide- fi awake, Master Mechanics. Every possible kind of a tool and machine was there for him to use with his own hands and men who knew all about them ex- plained everything to him. At the close of his first day he had learned what made motors run and why some wouldn’t run. For the first time in many days Tom was pleased with his work. CHAPTER 3. i Inside of a month Tom found he knew most of what there was to know about motors. He found every kind of equipment there was to know about. And he found that it was easy to learn. It was one a — of the few things he had ever done that he liked. oy : Each day his training took in new work until the p facts about autos, tractors and aviation were learned, through actual practice. As Tom put it, he was sure headed right.”’ CHAPTER 4. The more Tom Cooper learned about the automo- x tive business, the more his interest in the work grew. The time went by so pleasantly that almost before he knew it he was in his last week, learning how to manage a garage and by that time had decided that some day he would have a business of his own. CHAPTER 6. Before the end of the second month Tom gradu* y ated. He was now a Rahe trained man. “Here's a job for you at $150 a month to start,” said Mr. Rahe, as he handed Tom his diploma. Tom went to see the garage mentioned. ‘“‘Yes,’’ said the owner, “Mr. Rahe just called up about you. His O. K. is encugh for me—the job is yours.’ CHAPTER 6. Cooper worked at this job four months when the big chance he was looking for came. Best of all it was in his own part of the country, He went into the garage business for himself. Today Tom sup- | ports his wife and mother and has a mighty nice I} bank account. As he says himself, “I am my own His Rahe di- loma a ts ya es the day he grad- uates, boss and doing well. Rahe trained me to be success- ful from the start.” Here is a coupon that will open to you the same door of opportunity into which Tom Cooper walked to suc- cess. A special low tuition rate for Full Life Scholarship now if ,you fill out and send it at once to HENRY J. RAHE, Dept. 2889, Kansas City, "REE Boox Prot Missouri. MAIL THIS COUPON for Special Tuition Offer a nd Big 68-page Illustrated Cata- 4 log giving Proot of Graduates’ 5 Success and showing opportuni- ties now open, All Sent q | t 4 Name ...cccceccvcceses coccsccccesccccocernoecsessseeseseseee VU). ) eeeerreerrrrrrrrrrrrrtrt rit AGE.» 00-000e OCOUPAtion. .oscseereeseseererterrerercccrenee a a jo oe ee ee ee ee ee a

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11.000 MILES TO LEARN TIRE SURGERY Came half way around the world to learn this good paying profession. Today they are successful. Are making money fast. Are duplicatingrecords of other students—of Buchmann who made $800 in 1 month; of Oldham who made $2200 in 4 months; andof many § others. In every corner of this great globe—right in your own town there’s a pressing need for

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The Field for Tire Surgery Is cd IT’S AN OPPORTUNITY for YOU to quickly get into a business that PAYS BIG right from the beginning. We teach you FREE. YOU can learn easily. No special educational qualifications necessary. Unlike any § other process. HAYWOOD’S TIRE SURGERY is a scientific method of § RECLAIMING and REBUILDING discarded, wornout, gashed tires. By this system YOU can ADD from 4000 to 5000 miles to casings now thrown away as useless. Our FREE course M. HAYWOOD, President includes methods, how to handle a station, scale of Bavwood Tire & Equipment Co. x charges and all other necessary details to be successful. 1290 Capitol Ave., Indianapolis, Ind. Our FREE book explains everything. Send for a Mi bs my send me by rotere mail your A ag Ad ONCE. & EQ co on the new ay wood re. Surgery YWOooD TIRE UIPMENT so details course in 2 x epee ~~ en —- 1290 Capitol Avenue, Indianapolis, Ind. — WANTED Rider Aeonts Want ad BE ne gy Sy A ator taper Ae discoveries. Many of the new ideas come from the skilled work-

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styles, colors and sizes in the ik Ranger” line of bicycles. EASY PAYMENTS if desired eta il who iesale ag our (HALF. peas wholesale cas — ) . “DEL “y itself in Bes time. Will last va — Easy to use, printed sent. Print for others, Big PROFIT. Write factory ODAY for press catalog, TYPE, cards, paper,envelopes, THE PRESS CO., D-33, Meriden, Conn. Aggy ie rae to Taught by Mail ED FREE o' ot end’ 30 DAYS TRIA Ties Lamps, Wheels, =, S cries and —at half D NO but tell a ex- eetly Fan you need. Do not buy until you et our prices,terms and the bigF REE catalog. NM E A CYCLE COMPANY Dept. D 109 Chicago Send for a Complete Catalogue of

ded MASONIC BOOKS ete eee up to $412 “monthly and ving + ay OF 8D C quality J | d G d | dy Course on Navigation. ewe ry an 00 $ nce of a lifetime e . world as 3 aves omoer ata low . REDDING & co. ture is on the Seven Seas,’ Publishers and Manufacturers WORLD TECHNICAL INSTITUTE, 200 Fifth Avenue Dept Ss New York Dept. 101 Fuller Building Jersey City, N. J. . ee $3.00 Some on tow oe Age Eom T Fic Tenor Rarie: Boge ay i ws eee yo | CTORS Prov: Li allowance = old i instruments { | in exchange for the ‘ Gibso’ Get our new - CIATE FREE BOOK—112 pages lil yw E, Val- Dine "wondepal, new? sflin constgcton wih LiMiTED]| pre P oor Sradge Nesting? any free es BIG MEN tise on *“How to Practice. ‘ Make $1800 to $5000 or More Yearly That is what gives them chances for Teaching and Selling Gibsons promotion. They start in at a good Oresnes feacher. pblendid oP: salary — $110.00 a month and expenses. ies for andolin and important, for the safety of pad ay ae ae oie on their vigilance 4 class instruction and sale of when they do their work as we teach the ‘made’ ‘many 9 teeeere they attract the favorable attention * Their professionally ‘end f financial: superiors. Promotions then are rapid.

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either sex, Other positions ng on school education feeseias|| |) eacvareemeeme oa asin igo +4 er re time. e, Take the initia initiative, now, =e » ° 7 or Beitet ter Vice. unguele Bo good. THERE IS A be DEMAND 18 THIS FIELD : Our Capital ules toro encnnng ora ny Ww 8 our Do Do Business on Our Capital ago now hold positions. : el We pe J ate eer sell. tected. OUR BOOKLET tells of this ideal vocation cae waweremesees eee moss Se ereias mamaticdes cater 7 Parsons St.,halamazoo, ti fe ene to thoes 00 salary from the starthow you can SUPON Ar Mich., U.S.A. Gentlemen:— » fnterestes ganization, the 7 S- 6 oF ot Without obligation send me free § Direction sad Maintenance (below) is your key toa aed book, complete Catalog. free § of the Mandolin Orches- a much bigger future. Why not treatise formation about § tra,**bhy America’s most suc- ‘ou start at $110 a aponth and sie cessful director, Wm. Place, WE SECURE YOUR TION. le a neerite ne now aw for Catalog, " = <i Business eon well spares ay waits AGT ~ BUFFALO, N. Y. — ee i Ge\y : GIBSON] | |(QeiQMed) gerbatcto tessa rou daumes ‘Mandolin-Guitar Co.| | | ey ~pesccayatay: eR Sf ‘487 Parsons Street ‘ a Address 4

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Popular Science: Monthly Grinding a Drill Correctly Is an Art O matter how hard the material of a drill, the cutting edges even- tually become dull and must be re- ground. To the novice, this grinding operation may seem a mere matter of holding the tool against a rotating grind- stone, but’skill is required to sharpen’ the cutting edges satisfactorily. The illustra- tion shows one of the common ' faults met with ana . in drill grind- aril Barada ing. The point —. so that the . the drill ae ole 1S arger een groun than the drill off center, and as a. conse- quence one lip or cutting edge is longer than the other. A drill ground in this manner will wobble when in use and will make the hole too large. The side of the drill with. the longer lip reams the hole, while the other lip runs free, not extending as far as the hole’s radius. This fault. will be apparent from the illustration. On account of the liability to error, the hand method is used as little as possible by large machine shops in which work that requires extreme accuracy is done. Tool-grinding ma- chines that adjust themselves auto- matically are now made. Such ma- chines are as. nearly “fool-proof” as they can be made, with the result that the personal errors of the mechanic are almost entirely eliminated.

A Door Handle Made from a Shovel Handle HEN you have a door without a knob or handle and a shovel without a blade the two can be made to serve each other. Saw through the shovel handle just below the rivet under the handle opening. Bore a hole through the remaining ; ‘ee HANDLE portion, as in- dicated in the drawing, and a (7 similar hole QZ through thedoor ' 7 where the handle

bolt the two to- eee Stas gether with a ere is away toma long carriage bolt oll — and your handle is done. It can be applied to trapdoors and gates as well as doors. Does this article suggest other ways of utilizing ~ old tool “handles -now lying useless in the cellar ‘or about the farm? (i an. = eee =6|°6Cfee

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July, 1920 How to Prolong the Life of Expensive Shirts NDOUBTEDLY tthe greatest U wear in a man’s shirt occurs where the stiff lower edges of the starched collar rub the fabric with every movement of the head. Many expensive shirts are discarded prema- turely just because of wear and tear around the frontal half of the collar. A practical method by which such shirts worn only in this place may be restored perfectly, is described here. Remove the worn front panels of shirt by opening seams at front of ~WORN PARTS PAPER PATTERN a SHEET OF PAPER FIG.A. Why discard good shirts simply be- cause they are torn at the neck? Cut off the bad part, move the front up, and the shirt is practically new FIG.2. collar band, front of shoulders, front of armholes and down the sides. (A discarded safety razor blade serves aptly.) Keeping these worn front panels buttoned, place them on a sheet of paper and trace the outline of the whole shirt front (Fig. 1), then cut out the form for use as pattern. Placing this paper pattern on shirt front, shift pattern downward until worn part of shirt front appears above the pattern (Fig. 2); then trace the pattern anew on the shirt front and cut same to suit, carefully. When this front is sewed back in the shirt, the worn part has been displaced, and the front shirt tails are but slightly shorter, while the shirt is practically new again.—C. NYE. To Remove Spindle Bolts Easily ISHING to put in a new set of spindle bolts and bushings in my Ford, I was disagreeably surprised to find that it required an 18-in. pipe wrench, and an old, discarded pump barrel slipped over the end to lengthen it, to unscrew these bolts. Not caring to use these makeshifts again, I pro- cured a small can of flake graphite to which was added enough cylinder oil to form a thick paste; then, when the bushings were fitted and the parts assembled, the threaded ends of the spindle bolts and the threads in the lower part of the axle were coated with this mixture, and the bolts screwed up tight. Six months later the oil holes in one of the spindle bolts became choked or stop- ped up and I had no trouble in removing the bolt with the regular wrench used for that purpose.—Roy C. BRADBURY. ; “My Mama says this makes every electric socket twice as useful.” The Quality Plug It fits any electric light socket and gives Light and Heat or Light and Power from a single socket at the same time. No longer need you remove your electric light bulb to use your Toaster, Vacuum Cleaner, Washing Machine, etc. “Every Wired Home Needs Three or More’’ AT YOUR DEALER’S 3.350 Made only by BENJAMIN ELECTRIC MFG. CO. Chicago New York San Francisco When you buy Electrical Appliances ask your dealer to equip the cord with Benjamin No. 903 Swivel Attachment Plug. It screws into the socket without tawisting the cord. Benjamin No. 2452 Shade Holders enable youto use any shade with your Two-Way Plugs Study ENGINEERING by Reinforced Concrete Engineering Structural Steel Designing Mail Structural Drafting Concrete Drafting and Estimating An A-1 Engineer with 30 years of experience has arranged these courses for technical men who do not ‘‘know it all’’ and for High School graduates who wish to take up this profession asa life work. Itis really private tutoring by mail. Prices moderate... Free literature: write for it IMMEDIATELY. io) Wilson Engineering Corp., Box O, Hanover, Mass. “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 hear all right. The Morley Phone for the DEAF is to the ears what classes are to the eyes. :nvisible, comfortable, weightless and harmless. Anyone can adjust it.’ Over one hundred thousand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, 26 South 15th Street, Philadelphia EXPLOSION WHISTLE : RELIABILITY y The autoist can count on the BUELL inany emergency. Its dominant note compels instant action. Adopted as equip- ment by over 95 manufacturers. Easy to in- stall, simple to operate, no maintenance cost. Guaranteed for 10 years. In Single Tone or Chime. Ask your dealer or write us direct. BUELL MFG. CO. Cottage Grove at 30th, = Chicago Shipfitters, Structural Workers, Carpenters, Brick- layers, Mechanics, Plumbers, Pipefitters, Boiler- makers and others can earn more money if they know how to read Blue Prints. By our method, we train you in a snort time. Write for Catalog B, statin trade. We also teach Drafting. Bea Draftsman! Earn big money. Draftsmen in demand. tools FREE. Write for Catalog G. COLUMBIA CORRESPONDENCE SCHOOL Est. 1904 Dept. Y, Drexel Bidg., Phila., Pa. Books and 113

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I Have Been Successful and My Book “Motion Picture Electricity” will teach you in simple form how to install, operate and maintain electrical equipment for moving picture theatres and scenic effects. The book is handsomely bound with gilt edge containing 300 pages and 128 specially made illustrations, most of which are not found in any other text book. The price is only $3.00 delivery prepaid. I have been in the motion picture theatre equipment business for 12 years and my ex- perience is yours through my book, ‘‘Motion Picture Electricity.” ORDER COUPON J. H. HALLBERG, 1604 Broadway, New York City. Dear Sir:—Send postpaid to the address below your 300 page book entitled ‘‘Motion Picture Elec- tricity,”” price $3.00. Whoa! Garco knows that word Obedience is Garco’s most noticeable quality. It doesn’t hold you back when you want full speed ahead; it never fails to respond when you feel like a hurried stop. Garco Asbestos Brake Lining is easy to recognize. The name is stamped on every second foot. That is your assurance of 100% good brake service. Your dealer has Garco or can get it for you. General Asbestos & Rubber Co. Charleston, S. C. CHICAGO NEW YORK PITTSBURGH GARCO BRAKE LINING HIGH SCHOOL PUPILS Earn $5.00 to $15.00 a week during after-school hours. Are you interested ? Then write to Popular Sci y . 225 West 39th Street, New York Popular Science Monthly This Switch Mechanism Will Prevent Accidents By Philip G. Bernhotz O prevent the recurrence of a seri- ous accident, the switch-inter- locking apparatus, shown in Fig. 2, was devised. Switches A and B are ammeter- phase switches which must never both be closed at the same time. On the board these switches were arranged without a thought of an interlocking apparatus. They were used for years without serious trouble, because the supply cur- rentcameonly L from a50-kilo- watt gener- ator which was too small T A to cause much - @ 6 trouble when tes + shorted. About a year ago, however, this generator was removed and the switch - board connected di- rectly withthe current from a large power-plant. For a time all went smoothly but, when a mistake was made, there was a blinding flash which consumed the switchboard and seriously injured the operator. Fig. 1 shows the wiring diagram and switches required for reading the cur- rent in a three-phase circuit. A and B are two switches which must be used L L { 2 3 METER MOTOR FIGI The wiring diagram and switches required for read- ing the current in a three-phase circuit Here are the two switches, together with the interlocking mechanism one at a time in taking the readings, A being used for L1 and L2, and B for L3. These two switches are shown in Fig. 2 with the interlocking mechan- ism; C is a stick of hardwood shaped as shown in the top view, and held ina neutral position by the spring D. Switch A has a fiber-block fastened between the blades E; it carries an iron bell-shaped lever F that engages the end of the stick C. The stick Cis moved to the left, blocking switch B. Switch A is thrown to the left, stick C blocking the switch B. When switch A is out, the two small springs D hold the stick in neutral and switch B is free to enter. G, the curved end of the stick, should be covered with a strip of metal to make it more firm. The notch for switch B should be as narrow as pos- sible so as to lock switch A as soon as switch B enters its seat. A Simple Way to Make a File More Efficient FILE-HOLDER in common use has the disadvantage of being made of cast-iron. When a break occurs, the clamp is usually left intact. Likewise the handle of a small pipe- wrench outlasts the movable jaw, but it goes to the junk-pile with it. With the unbroken members of the two tools, the file-holder and wrench, the writer constructed a file-holder (ass) PART OF STILLSON rN WRENCH Ucramp Here is a use for an old broken-down wrench. It now acts as a file-holder and also helps to reduce filing time that was just as convenient as the original one and very much stronger. The under side of the wrench- handle was filed down as so to accom- modate a larger file-tange. The jaw was ground down at the sides and the clamp slipped on and retained with a projecting-pin through the hole in the wrench-jaw. This made an excellent file-holder and one which will outlast a dozen files.—JAMES M. KANE. A Safety Caster for the Stock-Room Ladder IG tool, and pattern storage- J rooms are usually provided ' with 4- and 6-ft. ladders, which often shift when in use, sometimes causing serious falls. Theillustrationshows a caster that has all the ad- vantages of the roller step- ladder, and that at the same time becomes firm and sta- tionary when a weight is set upon it. The caster housings are fastened to the four legs of the ladder 114 A ladder cannot slip if these casters are attached as shown by machine bolts in such a manner that the tension of . the springs lift it from the floor. The tension may be adjusted. by moving the cot- ter-pin. The square shank of the caster is compact and close to the side of the ladder and does not inter- fere with the foot space. Nearly. every supply store carries them, and they save theircost many timesby pre- venting accidents.-WILLIAM FARRELL. ES See SS See lCoee OL

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July, 1920 To Recut the Valve Seats on an Old Engine HEN overhauling an old engine it will generally be found that the valves have worn down their seats, leaving a shoulder around the edge PLAN VIEW TOOL STEM 1a # MMT MH HA agg RLLLLLLLAA 1B DEPTH REGULATING : SET-SCREW Why not make your own tool for recutting old valve seats? It will do fine work if turned slowly which hinders the passage of the gas and also causes the valve to catch and not seat properly. Make a tool, for cutting down the shoulder and for refacing the valve seat, of an old valve the size used in steel about 14 in. long. Cut a notch in the head of the valve so that the cutter will wedge in tight. The cut- ter is ground with the cutting edge straight and at the angle shown in the diagram. Then set it in the notch for cutting down the shoulder and refacing the valve seat. A bar of iron bolted to one corner of the cylin- der block and with a set screw in the other end directly under the valve guide is to adjust the tool to the proper depth as the seat is gradually cut down. The tool is turned with a brace and bit and it must be turned slowly, so that it wi'l cut the iron smooth with- out chattering.—P. P. AVERY. How to Make a Tapered Rope End HE proper way to finish a rope end so that it will go easily s through an eye- ] a let is shown in SF HICKNESS the illustration. First untwist two or three in- ches of the rope and cut the strands to half their present thickness. Then To taper aropeendis rewind the rope notahard problemand again, keeping to do so will enable each strand well a rope to go through an eyelet easily twisted up in the original direction. Then bind up the end as shown.—Morris G. MILLER. CYCLE TRADES OF AMERICA, Inc., 35 Warren Street Don’t you remember- [Es you and | turn back the years and be boys again. You remember how you longed for a bicycle—how you dreamed of having your very own—and then, one day the dream came true! Was there ever a happier boy in the world than you, the day you got your bicycle? What about your boy—your girl? Do you know of anything in the world that could bring them more pleasure—or could make them stronger and more healthy ? Do you know of anything they would want more? Read their youthful hearts and you'll find that the desire for a bicycle is enthroned there—just as it was in your heart. Give them this happiness. Give them the opportunity to-grow up healthy, rosy women and robust, four-square men. Give them the joy of seeing things—the inspiration to do things— and the chance to be things! Give them a bicycle! Not only boys and girls, but men and women get both pleasure and profit out of bicycling. The convenience of riding to work or school and ‘avoiding the hot, crowded cars —the exhilarating thrill of fresh air and red blood—the clear eye and “fit as a fiddle feeling”—these are what go hand in hand with pleasure in making the bicycle popular and a tonic for everybody. See Your Dealer Today. New York, U.S.A. 115

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Che rte ee eee oe pe ari 4 LEE TSE di ee ee aac No Other Typewriter Can Do This Over 365 2. styles of OF THE types and HAMMOND languages to select from. “Just turn the Knob” to change. There are many typewriters but only one scientific ‘‘Writing Machine.” Examine the varied types of the Mul- tiplex below and you'll understand why. TWO STYLES OF TYPE, or tno to five different languages, carried on the machine AT ONCE. "JUST TURN THE KNOB" and change instantly WULTIPLEX HAMMOND'S Lean changeable LwyWype Many styles, many languages Two types or languages al ways In the machine change The above samples of type give but a slight idea of the versatility of one of the greatest achievements of science. There is a special Multiplex that writes all the characters for higher and lower mathe- matics, gives chemical signs and symbols. That’s why the _Hammond_ is the popular machine with mathematicians, astronomers, engineers, and with people in every walk of life. Mail Coupon for FREE BOOKLET etal Who Count”’ and “The Miracle of the Multiplex.’’ MAIL COUPON TO HAMMOND TYPEWRITER CO., 639 E. 69th St., New York City a Pa “Reo” Cluster Metal Si ‘Shingles, V-Crimp, Corru- Seam, Painted or Galvanized Roof- idings, Wallboard Paints, etc., direct to you k-Bottom Factory Prices. Positively greatest offer ae made. Edwards “Reo” Metal Shingles cost less; outlast three ordinary roofs. No painti ng orrepairs. Guaran rot, fire, rust, lightning proo’ Free Roofing Book Get our wonderfully low prices and free samples. We sell direct to you and save you all in-between dealer’s E proaes.. Ask for Book SS ee oo r pom | Zd Low PRICED GARAGES Lowest prices on Ready-Made Fire-Proof SteelGarages. Set upany place. Send postal for Garage Book, showing —: THE ‘OWARDS MFG. CO 748-798 Pike St., Cincinaati, 6. Popular Science Monthly The Neatest Mechanical Job I Ever Saw The Popular Science Monthly will pay ninety dollars for the best answers HAT was the neatest mechanical job you ever saw, and how was it done? Some neat ones recently de- scribed in the PopuLAR SCIENCE MONTHLY were: overhead shaft repaired without removing it. brush made from an old pencil. bushed. A broken A magneto Tight pulleys quickly The action of a drill in soft metal made easy. Worn screws made as good as new. There are, of course, many other neat jobs, and we want to know in how many other practical ways they can be done. PopuLAR SCIENCE MONTHLY offers three prizes, Tell us! The of $50, a second prize of $25, and a third prize of $15,— to be awarded in accordance with the rules set forth below. Rules Governing the Contest (1) Contestants are not limited to the number of neat jobs, but only one method can possibly win the first prize, only one the second, and .only one the third. The contest is open to everybody. (2) The method must be clear- ly shown either in a photograph or in a drawing. If a drawing is sent in, it need not be made by a skilled draftsman. It is sufficient that it should be _ intelligible. While pencil sketches will be con- sidered, contestants are requested to make their drawings in ink on heavy white paper. The views should be sufficient in number to set forth the use of the appliance very clearly. The contestant’s name and address should appear on each sheet of drawings. (3) The drawings or photo- graphs must be accompanied by a description, preferably type- written, in which the method is clearly given. It must be written on one side of the paper only, and it should not be more than 500 words in length. The name and address of the contestant should appear in the upper left-hand corner of the first sheet of the written description. (4) The drawings and descrip- tion entered by contestants must be received by the POPULAR SCIENCE MONTHLY not later than 5 p. m. on Saturday, July 31, 1920. (5) The judges of the contest will be the editors of the POPULAR SCIENCE MONTHLY. 116 (6) The first prize of $50 will be awarded to the contestant who, in the opinion of the judges, has suggested the simplest and neatest job that you ever saw. The second prize of $25 will be paid to the contestant who sub- mits a method next in merit. The third prize of $15 will be paid to the contestant who sub- mits the method third in merit. (7) The winners of the contest will be announced in the earliest possible issue of the POPULAR SCIENCE MONTHLY. A _ descrip- tion of the methods which win the three prizes offered will duly ap- pear in the pages of the POPULAR SCIENCE MONTHLY, together with the names of the winners. (8) The editors of the POPULAR SCIENCE MONTHLY sshall have the right to publish meritorious manuscripts which do not win a prize. The regular space rates will be paid to the contestants who submit the manuscripts thus selected. (9) When a contestant submits more than one method, the de- scription and drawing by which each is set forth must be sent as a separate unit. (10) Manuscripts or drawings will be returned to contestants if stamps are enclosed. (11) Send drawings and specifi- cations to the Neatest Job Editor, POPULAR SCIENCE MONTHLY, 225 West 39th Street, New York City. Popular Science Monthly (Re ha a etn. RRL ra Pe PS 5 RRA IT ITE.

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July, 1920 | spare time study. | How much longer are you going to | wait before taking the step that is bound to bring you more money? } Isn’t it better to start mow than to wait | five years and then realize what the lj delay has cost you? | One hour after supper each night | spent with the I. C. S. in the quiet of |} your own home will prepare you for the position you want in the work you like best. Yes, it will! Put it up to us to prove it. Without cost, without obligation, just mark and mail this coupon. July, 1920 | | | | | | | | | | | | | “At Last—A Real Job and Real Money” | “And if only I’d started earlier, I could have had them five years ago. | I didn’t realize at first what spare time study would do fora man. Taking | up that I. C. S. course marked the real beginning of my success. three months I received my first promotion. | ing and I’ve been climbing ever since.” Every mail brings letters from some of the two million students of the International Correspondence Schools, telling of advancements and increased salaries won through |] In | But I kept right on study- | i iH INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7683, SCRANTON, PA. Explain, without obliqating me, how I can qualify for the position. or in the subject, before which I mark X, ADVERTISING SALESMANSHIP Traffic Management BUSINESS MANAGEMENT Private Secretary Commercial Law came Public Accountant —— Accounting Iway Accountant BOORRERPER Seenogmenber and Typist Good English Window Trimmer Show-Card Writer Sign Painter OIVIL SERVICE od Mail Clerk Mail Carri ier CART OONIST Perspective Drawing cospet Designer Wallpaper Designer Bookcover igner TEACHER Common School Subjects High School Subjects Mathematics a, OPERATING Automobile Repairing Auto, Electrical Work Name. ELEOTRICAL ENGINEER lectrician Electric Wiring Electric Lighting Electric Car a Heavy Electric Traction Electrical Draftsman Electric Machine Designer Telegraph Engineer Telephone Work AROHITECT Architectural Draftsman Contractor and Builder Building Foreman arpenter Concrete Builder MARINE ENGINEER PLUMBER & STEAM FITTER Heating & Ventilation Plumbing Inspector Foreman Plumber MINE FOREMAN OR ENGINEER Coal Mining Metal Mining Meta llurgist or Prospector Assayer TEXTILE OVERSEERORSUPT. Cotton Manufacturing Woolen Manufacturing Locomotive Engineer Roundhouse Foreman MEOHANIOAL ENGINEER Mechanical a igner etal Worker STEAM — Stationary Firem Gas ENGINE OPERATING Refrigeration Engineer CIVIL ENGINEER Surveying and Mapping nstructing aay aoe RAFTS FTSMAN - eetthnee Draftsman Structura) Engineer CHEMIST Engineer ~ Bi came mar 4 08 Motor Boat Runna'¢ AGRICULTURE POULTRY RAISER Occupation and 1 Street and No City. State. 7-26-06 Canadians may send this coupon to International Correspondence Schools, Montreal , Ca:vada ‘117

Page 106

DOUBLE Tire Mileage ae (& &

Val FREE We will send this hand- some and useful pencil clip to any boy desir- ing one, entirely free. Simply write for it. Mention Popular Sci- ence Monthly. NEVERLEAK TIRE FLUID 30 cents worth in each tire is a sure protec- tion against leaks. Stops them on the run. No trouble, no delay. Save the high cost of new tires. Get many extra miles out of your old tires by treat- ing them with old, reliable

Actually preserves the rubber and fabric. Yj) Makes tires wear twice as long. fi At all dealers. Get the genu- 2% ine Neverleak. Don't delay.

Buffalo Specialty Co., Ellicott St., Buffalo, N. Y. | I >= WA 1s ty, AW, NL \ te let ener ‘ 7 fea 0 (om tw Sqnare Cee : ~ f . S ix LON 59 GR TS0NEDAY tra Shook of Flint Did That amount of business in one day making and selling popcorn Crispettes

with this machine. Profits 269.00 Mullen of East Liberty bought two outfits recent- ly. Feb. 2, said ready for third. J. R. Bert, Ala., wrote Jan. 23, 1920; “Only thing I ever bought equalled advertisement.’’ J. M. Pattilo,Ocala,wrote Feb. 2, 1920; “‘Enclosed find money order to pay all my notes. Getting along fine. Crispette busi- ness all you claim and then some.” John W. Culp, So. Carolina writes, “Everything is going lovely— business is growing by leaps and bounds. The business section of this town covers two blocks, Crispette wrappers lying _every- where. It’s a good old world after all. Kellog $700 ahead end of second vveek. Mexiner, Baltimore, 250in one day. Perrin, 380 in one day. Baker, 3,000 packages» one

Start You in Business Little capital,no experience. Teach you secret formula. BUILD A BUSINESS OF YOUR OWN The demand for crispettes is enormous. A delicious confection made without sugar, Write me. Get facts about an honorable business which will make ou independent. You can start right in your own , town. Business will w. You won’t bescramblingand ! crowding for a job. You will have made your own place, PROFITS $1000 A MONTH EASILY POSSIBLE Send post card for illustrated book of facts, Contains enthu- siastic ketters from others—shows their places of business, tells you bow to start, when to start, and all other information It’s free. Write now. LONG EAKINS COMPANY 1505 High Street SPRINGFIELD, OHIO Arithmetic of Electricity A practical treatise on electrical calculations of all kinds reduced to a series of rules. $1.50 Postpaid. Popular Science Monthly, 225 West 39th St., New York

A Convenient and Effective Knife-Sharpener OR several reasons, many electri- cians consider it useless to carry an oil-stone in their tool-bag. It seldom lasts for any length of time, owing to the abuse to which it is subjected, and moreover, it is not suited to the main purpose for which it is carried, that of keeping the knife in good shape for skinning wires and cutting “loom.” The blade of

WEDGE BLOCK

SANDPAPER the knife used in AND |||!) cuttingloom gets EMERY-CLOTH ||| covered with the substance with || which the wire iis impregnated J) and renders the cutting difficult. This is especial- ly true when ‘‘weather proof”

WEDGE This useful little knife-sharpener for electricians is made fromablockofwood insulation is be- ing skinned from wires. These substances usually gum up the surface of an oil-stone after one or two sharpenings. The best way to keep a knife in good condition for such uses is first to remove the sticky coat- ing from the blade with a piece of medium sandpaper, then to touch up its edge on a piece of fine emery-cloth. In the illustration is shown a con- venient little substitute for the oil- stone. It consists of a piece of wood- strip about 2 in. wide and 5 or 6 in. long, with a thickness of an inch or so. A wedge-shaped piece is sawed from each end of this block, the wedges thus made being used to stretch a strip of sandpaper tightly on one side and a strip of fine emery-cloth on the other. The abrasive surfaces can be re- newed in a jiffy; the device is light and non-breakable and it costs noth- ing.—JOHN A. WEAVER. How to Make an Extensible Bit-Extension HE very fact that a bit-extension is intended to lengthen the reach of an auger-bit often makes it desirable that the extension itself be capable of being extended. While occasions call- ing for this adjustment are compara- tively rare with the ordinary carpenter, ' ' 4

ae ; ess cut 4 = a > ——— e THREADED THREADED ROD = THREADED COLLAR COLLAR

= et BIT EXTENSION EXTENDED It is the work of a few moments only tom ake the auger-bit extend to any length desired they are quite frequent with bridge carpenters, well-rig builders, and other mechanics working on heavy con- struction jobs. 118

Popular Science Monthly

Py is an attachment that makes any cooking or heating stove a gas stove. No coal or wood. Cooks and bakes better than coal or wood in the same stove, Makes Its Own Gas {f0™,<02! oi! n (kerosene) at one-fourth the cost of city gas. Everybody knows gas means cleaner, cheaper, quicker cooking, and a cooler kitchen. No fires to start, no ashes, no chopping, at es poking and dragging of coal. Saves hours o! work and loads of dirt. No smoke nor odor. You regu- late heat with valves. Simple, safe, easily put in or taken out. Simply setson grate. Nodamazge to stove. Lastsa lifetime. Thousands of users. In use iG years. SAVES MONEY-- FITS ANY STOVE 16 different models. one for every stove. Write for free literature—tells how two ninety-seven pounds of coal. Oliver Oll-Gas Burner & Machine Co., 2007 Pi St, Louis, Mo.

ine St., Western Shipments From San Francisco.

= Duratex Guaranteed Shirts «sc months’ wear Fine percale coat style shirts, assorted stripes, laun- dered or soft cuffs. Neatand dressy. Or 3 soft pongee summer shirts, cool and comfortable, outing style. Introductory offer—Send $6.85 and receive shirts post- paid or send $1.00 and pay $5.85 and postage when re- ceived. Order today, state size. Money back if not satisfied. Duratex catalog of guaran- teed furnishings free. We can fit any sized man. Large sizes a specialty. GOODELL & CO., 552 DURATEX BLDG., NEW YORK Largest mail order wholesale haberdashery house in the world

———- —— “Clear O

ut RatsIn3 Nigh *‘Rough On Rats’? rids your premises of all rats and mice in 3 nights, Change the bait you mix with ‘“‘Rough On Rats’—that’s the secret. Rats won’t eat the same food that they know killed others. Varying the bait fools them. Druggists and general stores sell *‘Rough On Rats’’—the most economical, surest exterminator. Write for ‘Ending Rats and Mice.’’ Mailed free to you.

Violin, Hawalian Guitar, Ukulele, Guitar, Mandolin, Cornet, Tenor Banjo or Banjo Wonderful new system of teaching note music by mail, To frs' pupils in each locality, we give a $20 superb Violin, Mandolin, Ukulele, Guitar, Hawalin Guitar, Cornet, Tenor Banjo or Banjo abso- lutely free. Very small charge for iessons only. We guarantee sc- cess or no charge. Complete outfit free, Write now. No obligation, SLINGERLAND SCHOOL OF MUSIC, Inc., Dept. 27, CHICAGO, ILL “Lighting Fixtures” Ready to hang. Direct from manufacturers. % Completely wired including glass- » ware. 6) Send for new No. 18 catalogue. ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa.

_ Popular Science Monthly

Page 107

July, 1920 The illustration shows a simple way of accomplishing this result without at all detracting from any desirable qual- ity of the tool. The method consists in simply cutting the stem near the shank and head, threading the cut ends, and re-connecting them with a pair of sleeves made from seamless tubing. The sleeves should be forced on the threads, on the shank-ends left back of the chuck, and on the square end, so that the only thing necessary to lengthen or shorten the extension is to screw the central section out and the desired section in. The threads can then be set up with a pipe-wrench or in the bench-vise which will prevent any possibility of their coming loose. Several threaded rods of different lengths may be kept on hand so that the same extension may be lengthened in a few moments from a few inches to several feet.—HENRY SIMON. Putting the Crippled Gas- Stove Back to Work ROKEN cast iron is difficult to repair in the ordinary way, and is, as a rule, not worth the expense of a welding operation. The gas stove shown in the accom- panying photograph was broken by a fall, which smashed its foot into small pieces. The foot was replaced by a Does this gas-stove repair sug- gest means of restoring to use other broken cast-iron articles? substantial and lasting repair, which consisted of 5%-in. strap-iron, as shown. Two pieces of strap-iron were used: one piece served as a cross-bar, and the other as the foot. Three holes were drilled into the cross-bar, one in the center and one at each end. One hole was bored through one end of the foot. The cross-piece and the foot were held together with a short stove-bolt. The cross-bar was then bolted to the open- ings in the stove with two more short stove-bolts.—FRANK W. HARTH. July, 1920 as you would LEARN DRAFTING At Home-In Spare Time in actual practice Get into this constructive branch of industry where big salaries are paid. No previous training is nécessary to becomé a capable draftsman with the help of the Columbia School of Drafting. You can master the practical lessons of our famous home study course, at home, in spare time. You will be personally coached and instructed, by mail, by Roy C. Claflin, president of the school, whose long experience asa draftsman and teacher, especially qualifies him to give you the training you need to become a successful Draftsman. CHIEF ENGINEER $5,000 to $50,000 a year Draftsmen: Get $35 to $100 Become a Specialist We not only give you thorough and prace tical training in Mechanical Drafting, teach ing you to make actual drawings as you would in any drafting room, but the additional benefit of a post- graduate course in some special branch of drafting. A big field of opportunity is thus CHIEF DRAFTSMAN $50 to $150 a week a Week Because of the importance of his work the draftsman is paid a big salary and is al- ways in line for advancement. The draftsman’s pay is from dustrial field paying as high as How **Columbia’’ Students Succeed Students of the Columbia School of Drafting often secure positions at $2,000 or more a year to start before completing the course. Hun- dreds of men and women with “Columbia” training are now mak- ing good with big concerns all over the country. Many more are needed for splendid positions now open. Here is what “Columbia” training is doing for some of our graduates; Laurence John- ston, over $5,000 a year; George Murray, $45 a week to start: G. Tangorra, $2,800 a year; A. L. Gash, $140 a month to start; W. S. Burfoot, $150 a month to start; T.R. Brown, $2,860 a year; R. Fowkes, $3,700 a year. These are only a few of a great number of similar cases. This Complete Drafting Equip- ment Furnished to students of our school. The instruments are of standard American make of the best quality, fully guaranteed, and become your property on completion of the course. Every instru- ment needed for the course is included. week. A knowledge of drafting is the step- ping stone to big technical positions in the in- opened to you as a trained specialist in this profession. DRAFTSMAN $45 to $100 a week $35 to $100 a LEARN DRAFTING $50,000 a year. AT HOME Big Concerns Employ ‘‘Co- lumbia”’ Graduates The best concerns in America employ Columbia graduates in their drafting departments because of the thorough practical training we give which enables them to step right into important draft- ing positions. Our diploma is the enter- ing wedge into big drafting rooms every- where. As a Columbia graduate you are recognized as an experienced draftsman, not asa mere apprentice. Our training spells Success for you. Why be satisfied with a grinding, underpaid position when there are hundreds of promising positions open to you in the big field of Drafting. We are called upon to place trained draftsmen more rapidly than wecan producethem. General construc- tion companies, manufacturers, railroads, ship building concerns, engineering projects, etc., need draftsmen today in greater numbers and at better salaries than ever before. Send This Coupon Today Let us tell you the fascinating story of Drafting and how you can master this lucrative profession of big salaries and steady advancement through our help. Write today to COLUMBIA SCHOOL OF DRAFTING, Roy C. Claflin, President 14th & T Sts., N. W., Washington, D.C. SS Se seeeeaeceseses:s, ~ 2a Dept. 1140 2a e e COLUMBIA SCHOOL OF DRAFTING, "" "ez, Roy C. Claflin, President Dept. 1140 14&T Sts., N. W. Washington, D, C. I am interested in chanical Drafting. trated book your practical training in Me- Please send me Free, your illus- ) of particulars, testimonials, terms, etc. I am also interested in the special post-graduate course checked below: ” (Mechanical Drafting, or Machine Drafting is the foundation course and is complete in itself.) Architectural Drafting. . .. Ship Drafting........ Automobile Drafting Statistical Drafting... Electrical Drafting Radio Drafting....... Aeroplane Drafting....... Automotive Drafting Special Machinery Drafting Hydrographic Drafting Sheet Metal Drafting... .. Machine Design. ... . Structural Drafting....... MS BPOa ccc cces Highway Drafting........ Shop Mathematics... . Patent Drafting. Po Ae aE Builders’ Course...... Topographical Drafting. . . Address....... ES er Tee me ee a 2 ee ee

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"Get the Coaster Wagon With Silo Wheel onthe Sides Tony Don't Iet them sell you any other kind. The Auto-Wheel is the genuine Coaster wagon—and it’s the only Coaster that will admit you to our Auto-Wheel Club. With the Auto-Wheel you can join our club and takein all our good times. You know it’s a big, speedy coaster—so strong that it will carry a 1,000 pound load with ease—so fast that it will beat any other wagon made, Prize Contests Our new MAGAZINE for boys tells of the prize contests we are holding periodically. We'll send you a copy of the magazine if you will send us the names of three coaster dealers, mentioning which one handles the wagon with “‘eftuto-Wheel”’ on the sides. We'll also send youa booklet telling you all about our Auto-Wheel Club, which you can organize. The Buffalo Sled Co., 157 Schenck Street, N. TONAWANDA, N.Y. In Canada: Preston, Ont. Shoot Without Noise Do away with that old fashioned report, and the disturbance. Avoid flinching, improve your accuracy and enjoy pre- cision shooting any- where at any time witha MAXIM SI mana Price, .22 cal., $6.00. Send 6c in stamps for catalog and booklet of humorous stories of noiseless shooting. The Maxim Silencer Co. 91 Homestead Ave., Hartford,Conn. Soe gta haggle ls nena as Perle Fis gta abn er Build Your Own PHONOGRAPH It's Easy With Our Help A few hours’ interesting work saves many dollars and gives you a machine exactly to suit your ideals, We furnish motors, tone arms, case material, blue prints Teen NYT and full instructions. Plays any " +444 ry ithe record. You can make fine profit VA te building phonographs for your friends. Write Today for Ovr Free Blue Print Offer Agents wanted for our ready built phonographs Choraleon Phonograph Co. 706 Monger Bidg., Elkhart, Ind. * An Electric Light for the Lawn-Mower OR the man who gets home late at night and wants to mow the lawn some sort of a light may be necessary to facilitate his work. A TO. HANDLE Q. SWITCH ELBOW ELECTRIC SEARCH- BATTERY Why disturb the neighbors with early morning lawnmowing? Attach alight to the machine for evening work common bicycle searchlight is just the thing and can be attached to the handle of the mower. Set a pipe flange on the top surface of the handle about half way up. Screw a 6 inch nipple into that and an elbow on the top of the nipple, pointing back towards the end of the handle. Then set a horizontal piece of pipe in the elbow about 12 in. long. The light bracket can be attached to the upright nipple and the battery can be suspended from the horizontal piece, as on a bicycle frame. The switch can be carried up to the cross handle at the top. By setting this arrangement fairly high on the handle all flying grass will go under the light and not interfere with its illumination. —L. B. ROBBINS. A Device for Distributing Potatoes and Corn Evenly SIMPLE marker to be used for spacing rows for corn, potatoes, etc., can be made from parts found around the average farm. The dia- gram shows the construction in detail. The cross-bar A is made from a stick of wood 4 in. by 4 in. To take NAIL FIG2 . — Sa ——= = NAIL CULTIVATOR y REQD wom This Car This nifty little car driven by gasoline motor, can be built ~ by any boy. Parts. furnished and _ price list of parts to build pe lad’s car. SYPHER MFG. CO., 174 Sypher Bidg., Toledo, Ohie. ing plans” wing how: Make from cast-off parts found around the farm, this homemade potato- and corn-row marker does excellent work the shafts 2-in. holes are drilled at B These shafts can be made from young trees, for these have the neces- sary taper and are much more flexible than straight sticks. A large nail, 120 _ Popular Science Monthly For Outdoor Sleepin3? “THE COT OF MANY USES” HEN the hot, sultry nights come—in the city—the coun- try—or the camp, this “‘Gold Medal” Cot with mosquito netting will be appreciated. There is no greater joy than outdoor sleeping and there’s no better way to enjoy it than with a Gold Medal Cot —comfortable, convenient, light and strong. At Furniture, Sporting Goods and Hard- ware Stores and Tent-Makers. Write for Catalog and Dealer’s name. GOLD MEDAL CAMP FURNITURE MFG. CO. 1723 Packard Avenue RACINE, WIS. For SO yoare makers of Practical Folding rniture for Home and Camp FROM THE ‘START Model F Every auto owner needs frequent tire repairs. Badger mal teecae makes the work quick and easy. Smallinvestment puts youintoa business of your own, paying up to $200-$300 a month, if = TEACH YOU FREE ‘bes at ractory, or by mail. Show you ow to get thebusiness and handle your shop. Best system, best ma- chines and money-making FREE AID SERVICE. Writefor Tells how to get igte Catalog the lucrative field right ull_ description of Badger outfits. It’s free—write. Tire Repair Equipment Co. 200 Johnson St. Appleton, Wis. SELL NO CLOT BUT SAVE YOU MONEY. OUR WONDERFUL, SIMPLE RENOVATING PROCESS APPLIED AT HOME MAKES OLD CLOTHES NEW Provides You With Clean, Fresh Nicely Pressed Garments Each Morning; c starts you in a remunerative usingss, ‘e have more than a score of p MONEY-SAVING AND MONEY- MAKING ‘SPECIALTIES The Economy Garment Cutting System, The Economy Hand Button Hole Maker, The Economy Fabric (wool, silk, etc.) Test, The Economy Perfect Figure Developer, The Economy Anti-Shrink Process, The Economy Anti-Fade Process, Etc. Send 50 cents for ‘‘Econony and Correct Attire,” from which men and women can learn how to dress better for less money. Immediate Results. Further particulars upon request, address, ECONOMY EDUCATOR CORPORATION, Dept. 49 2537 Broadway, New Y: Agents, yd and District HManegers Wanted RUNS ON KEROSENE ALCOHOL OR GAS ANYWHERE Genuine comfort and relief in the heat | day and night may be yo: rs with one ! of these remarkable non-electric fans. Every home and office needs one for health and efficiency. This fan is ideal for the sick. It is & proved success, quiet and convenient and runs any- where at almost no cost without elec- tricity, sprinzs or wires. Sixth season. Three models. Three sizes. BE WELL—KEEP COOL LAKE BREEZE MOTOR 581 West Monroe St., - - - Chicago BIG MONEY SAVINGS FOR 2 YOU =» Used ant ogy Used bicge singles gh Swine, - cocaine cae — = 4 New bi- m eaed and motorcycles at Fac- ou save dealers’

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July, 1920 driven as shown, .will hold each, shaft in place. Strap-iron braces, screwed to the shafts and cross-bar, will serve to hold the contrivance rigid and pre- vent side-sway. Three markers are used, one serving as a guide and the other two to mark new rows. Old cultivator-teeth are bolted to lengths of wood 2 in. in diameter. The distance from the bottom of the teeth to the center of the cross-bar should be about 12 in. To prevent the marker from jump- ing out of its course or being broken by striking stones, etc., the holes A should be made longer than they are wide. This will permit a certain amount of play and will leave the tooth-holders rigid. The two outside markers are fast- ened in the same -way as are the shafts; that is, with a large nail, as is shown in Fig. 2. The hole through B should be a trifle larger than the nail so that there will be sufficient play to permit the piece holding the teeth to move back and forth in the hole A. The central marker is fastened with an eye-bolt instead of a nail. The single tree chain is fastened to this eye-bolt. The guide-bar, which is used for keeping the marker in its course and lifting it over obstacles, is a 34-in. pipe, bent to shape and then tightly jammed into the holes. This vn Saw-Buck Promotes Efficiency EMENT has many advantages over wood in the construction of a saw-buck, or block for holding logs while sawing them into stove lengths. ~ This substance is heavy enough to stand solidly under all stresses, it never LEATHER STRAP OR CHAIN . a re NT TS ae The usual saw-buck is made of wood and the whole contrivance is as a rule rickety. Here is one that will clamp the log firmly wears out, and it is neat and attractive. The form for casting is merely a rectangular box that can be easily dis- mantled. The triangular groove in the top of the finished contrivance is pro- duced by nailing two short pieces of wide board together to form a V- trough, and laying it in place when casting. Two stout metal rings should be attached to rods or wires, and these rods or wires should be imbedded in the cement, near the top, two on each side. The rings are very handy for fastenting straps or chains for holding the log solidly to the block. Use a cement mixture of 1 part cement, 2 or 3 parts sand and 3 parts gravel or large pebbles.—JAMES P. LEWIS. POSITION AUTOMOBILE ENGINEER REPAIR MAN CHAUFFEUR SALARY . "120 win $90 wax °00 wis Put Your Name on This Pay-Roll Men like you are wanted for big pay positions in the fascinating field of automobile engineering. We have made it easy for you to fit yourself for one of these positions. You don’t have to go to school. You don’t have to serve an apprenticeship. Fifteen automobile engineers and special- ists have compiled a spare time reading course that will equip you to be an automobile expert without taking any time from your present work. AUTO BOOKS 6 Volumes Shipped Free Now ready for you—an up-to-the-minute six- volume library on Automobile Engineering, covering the construction, care and repair of pleasure cars, motor trucks and motorcycles. Brimming over with advanced information on Lighting System, Garage Design and Equipment, Welding and other repair Partial List of Contents More than 100 blue prints of wiring dia- grams. Explosion Motors Welding Motor Construction and Repair Carbureters & Settings Valves, Cooling Lubrication Fly-Wheels Clutch Transmission Final Drive Steering Frames methods. Contains everything that a mechanic or = an engineer or a motorcyclist or the owner or pros- Ignition as I J pis Starting and Lighting pective owner of a motor car ought to know. Writ- op ovstems op Kinks ten in simple language that anybody can understand. Tastefully bound in American Morocco, flexible covers, gold stamped, 2,650 pages and 2,100 illus- trations, tables and explanatory diagrams. A library that cost thousands of dollars to compile but that comes to you free for 7 days’ examination. see the books in your own home or shop. Only Tc a day Just mail coupon and pay express charges when books arrive. You can read them and study them for seven whole days before you decide whether you want to keep them or not. If you like the books send only $2.80 in seven days and $2 a month until the special introductory price of $24.80 has been paid. (Regular price, $36.00.) Along with the set goes-a year’s consulting membership in the Ameri- can Technical Society. (Regular price,$12.) Thisgreat bargain offer must soon be withdrawn. Send No Money Now Don’t take our word for it. See the books without cost. There is so much profit in this offer for you, that we urge you to waste not a moment in sending for the books. Put the coupon in the mails today. Send no money—just the coupon! American Technical Society Dept. A-20-B, Chicago, III. | dod het te ET | Commercial Garage Design and Equipment Electrics Storage Batteries Cars and Repair Motorcycles Commercial Trucks Glossary Not a cent to pay in advance. First you American Technical Society, Dept. A-20-B, Chicago, Ill. Please send me the 6-volume set, Automobile Engineering, for 7 days’ examination, shipping charges collect. If I decide to buy, I will send $2.80 within 7 days and the balance at $2 a month until the $24.80 has been paid. Then you send me a receipt showing that the $36.00 set of books and the $12 Consulting Membership are mine and fully paid for. If I think I can Mail The get along without the books after the Coupon For ; rt lg I will return them at These Books |) IO isiiigace Res swine bende etaak en . Peo 8 OOS ect eee ane PO i Fi. Fee ids ose ae cee 121

Page 110

' i} i] { j ' i { ee eee ene a See ari ash © wii eh 0 AES RNR we we aeons Just Published Experiments with 110-Volt Alternating Currents. By J. D. ADAMS Why does the young electrician seldom have any practical knowledge of the 110-volt alternating current— the most important form in which electricity is used commercially ? This condition exists because the many books for the beginner, excellent though they are, all seem to so carefully avoid the alter- nating current as though it were something that the youthful electrician should not tamper with. The purpose of this book is to show the amateur electrician that the 110-volt com- mercial circuit may be handled with perfect safety and without involving the expense necessary to maintain a power supply. The only way to gain a thorough under- standing of electricity, as it is used com- mercially, is by direct personal experiment. The knowledge thus gained is of vastly more value and importance than that acquired from the performance of the stereotyped series of battery experiments so uniformly described in the text-books. The many experiments described in this book were all performed at a time when neither a machine shop nor a laboratory was available. The apparatus involved was necessarily made as simple as possible con- sistent with the securing of striking results. Fully Illustrated Price, Postpaid, - - $1.75 ELECTRICIANS’ Wiring Manual By F. F. SENGSTOCK, E. E. This book contains all the essential infor- mation needed for the proper installation of lighting and power systems in houses and other buildings. It is written in simple, plain English by an Electrical Engineer with many years’ experience on the Chicago Board of Underwriters. Profusely illustrated and contains many tables and formulas. 448 Pages, 415 Illustrations. New Edition 1920. Pocket size, flexible binding. Price, Postpaid, $2.50 CONSTRUCTION of Small Alternating Current Motors By PROF. A. E. WATSON, Brown University This book contains complete. instructions for building small alternating current motors in several sizes. The designs will be found in harmony with those of the very best manu- facturers and they can be worked out by the amateur for making useful instruments. Some of the subjects taken up,are ‘‘Char- acteristic Features of Alternating Current Motors,’”’ “Construction of a One-Half Horsepower, Single Phase Induction Motor,” “Procedure in Testing and Using an Alternat- ing Current Generator or Synchronous Motor.” Clear, concise directions and careful drawings are features of this book. Fully Illustrated. Price, Postpaid, $1.25 Popular Science Monthly 225 West 39th St., New York Popular Science Monthly A Lathe with a Change Speed Power Plant By P. P. Avery VERY serviceable and accurate lathe may be built of scrap parts, and a novel means of speed change may be obtained from an old auto- mobile transmission and engine fly- wheel. The lathe is made from two FLUSH SET-SCREW~ i Le cy PiPC «3 STEEL SHAFT FLAT IRON. rod with a tempered center point and T handle. The chuck bearing is fitted with a shaft and filler made from pipe which has a thrust and is held in place with a key and safety set screw. The Ie" LOCK-NUT ‘ FLYWHEEL BEARING ( FLYWHEEL &CWwICH Si i : HANDLE. RIVETED: ON me u —= GEAR Nt rier | PULLEY IN PLACE 1 OF UNIVERSAL JOINT : yf 3'FLAT IRON Besides an old automobile transmission for the various speeds necessary, pieces of scrap iron were used to make this lathe pieces of L iron, 2 by 5 in. for the bed frame with the legs of 14 by 3 in. flat iron bent, drilled and cut as shown. Place filler pieces at each end to separate the two members of the bed frame, using hard maple wood or cast iron of 11% in. thickness by 3 in. wide and 5 in. high. These fillers are held in place by %% in. bolts and double lock nuts, with the bolt end riveted over. The chuck and tail bearing U pieces are formed of 4 by 3 in flat iron, the chuck end being securely and permanently bolted in place, while the tail is movable for adjusting to any distance along the bed. The wot bolts in each bearing are *¢ in. and pass through a filler guide of 1'°/3. in. thickness. A 14 by 3 in. plate washer on the bottom makes a steady draw-up adjustment. Thread through both sides of the tail and make a 34 in. pulley on the end is connected by a 3 in. face leather belt to a pulley of the same diameter on the tail shaft which is, in this case, the shaft pro- jecting from an old automobile trans- mission. The illustration shows every part in detail and the amateur should have no trouble in assembling the various components. The clutch pedal is fitted with a strip of 144 by 114 in. flat iron bent as a handle and, of course, the old gear shift lever can still be used without changing it. The operation is as follows. Pull for- ward on the clutch lever which will dis- engage the clutch and change the gears to the desired ratio with the other hand on the gear shift lever. This keeps the motor always normal and gives three varying speeds to the lathe as required. The gears may be changed without closing down the motor. Steadying a Ladder Against a Slanting Roof LADDER placed against the gable edge of a slanting roof is always wabbly and dangerous. To overcome this is an attachment which fits the ladder and can be through it. This extends out about an inch. Then a flat piece is con- structed to fit down over the stud and slide over it a short distance each way, by means of a adjusted to meet the height and pitch of the roof where the ladder touches. A loose clamp is made in the shape shown, and fitted around one leg of the ladder, where it will slide up and down. It is tightened in place by a bolt. This bolt has a flat surface on the bottom which bears against the ladder. | A hole is then drilled through the middle of the clamp and a stud riveted wabbly ladder? "199 ROOF Have you ever tried to climb a ‘Here is an exten- sion which will hold the ladder rigid at any angle at which it is placed slot. One end of the slotted piece is turned out at right angles and riveted toa second piece used to bear against the edge of the roof. This arrangement is held in place on the clamp by a wing nut. By sliding the clamp along the ladder to the desired height and adjusting the slotted piece the right distance from the gable edge, the worker will be assured of a steady ladder.—L. B. ROBBINS. STUD AND WING-NUT CBOLT ’

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July, 1920 Clip for Holding Photos and Drawings HE usual method of holding drawings or photos for copying is by fastening them with thumb tacks or similar means to a board. The device illustrated will not mar IN Why mar your photographs with thumb tack holes when spring arms will hold them just as well? the drawing as would a thumb tack and will hold it firmly in any posi- tion. It is composed of two arms, one arm inflexible and the other springy. The curved end of the springy arm rests on the drawing and holds it in place. The twe arms may be swung in any position. As four devices are required, all the parts can be multiplied by four. For the arm A take a piece of strap brass 34 in. by 1/16 in: thick, and 4 in. long. Drill two holes in each end. The hole in one end is for a fulcrum rivet of arm B. Make the arm B from 1/32 in. spring brass and shaped as shown. The rivet should be tight enough so that the arm B will not swing loosely.—F. W. HARTH. When a Broom Is a Shoe- Cleaner HEN the bootblack is charging ten cents plus the tax of a healthy ‘‘tip’” for each pair of shoes cleaned and polished, why not dupli- cate the example of J. H. Vaughan, of Texas, who has found economical use of a discarded broom as a shoe and boot cleaner? Of course, the hand- made device is not capable of admin- istering the shining fluid but a thor- ough cleaning of the leather is the big end of the job. So uncover that frazzled broom long sequestered in some corner, eliminate the straws and strings by cutting, as il- lustrated bythe accompanying diagram, and make a notch sufficiently large for your foot to form in- timatecompan- ionship there- with. Saw the handle off to a convenient length to insert in a hole in the steps or porch of your home. After dispensing with the straw, the sides are compactly laced.—S. R. WINTERS. CUT OUT AND BIND SIDES t = FASTEN 70 ~=— FLOOR Cut the broom in the manner shown above, insert it in a hole in the front steps and it is a shoe cleaner Show Men The way to whiter teeth All statements approved by high dental authorities Women should test this new method of teeth cleaning. They usually decide the family tooth paste. Tooth protection depends largely on them. There are new facts to consider. And every woman, for her sake and her family’s sake, should prove them. That film-coat Most tooth troubles are now traced to film. To that viscous film which you feel with your tongue. Millions of teeth are dimmed and ruined by it. Film clings to teeth, enters crevices and stays. The ordinary tooth paste does not dissolve it, so the tooth brush leaves much of it. It is the film-coat that 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 Millions of germs breed in it. They, with tartar, are the chief cause of pyorrhea. So, despite the tooth brush, it these troubles have been constantly increasing. Now we combat it Dental science has for years sought a way to fight that film. Not on the surface only, but between the teeth. That way has now been found. Able authorities have amply proved it. The method is now embodied in a dentifrice called Pepsodent. To millions it has brought a new era in teeth cleaning, and leading dentists everywhere are urging its daily use. Ask for a ten-day tube Everyone is welcome to a test of Pepso- dent. Watch the results, read the reasons for them, then judge it for yourself. Pepsodent is based on pepsin, the di- gestant of albumin. The film is albu- minous matter. The object of Pepsodent is to dissolve it, then to day by day combat it. A new discovery makes this method possible. Pepsin must be activated, and the usual agent is an acid harmful to the teeth. But science has found a harmless Pepsadéent REG.U.S. The New-Day Dentifrice Ascientific film combatant com- bined with two other modern req- uisites. by all druggists in large tubes. Now advised by leading dentists everywhere and supplied activating method, and active pepsin can be used to fight this film. Pepsodent combines two other modern requisites. And these three great factors do what nothing else has done. Send the coupon for a 10-Day Tube. Note how clean the teeth feel after using. Mark the absence. of the viscous film. See how the teeth whiten as the film-coat disappears. You will know then what is best for you and yours. Cut out the coupon now. his is too important to forget. Pe oe ee ee ee ee ee ae a oe ey 10-Day Tube Free THE PEPSODENT COMPANY, Dept. 593, 1104 S. Wabash Ave., Chicago, Ill. Mail 10-Day Tube of Pepsodent to SHC ee OOM De CSS CE 6 sD 9 Rie OS OS OO RS Only one tube to a family o-oo 123

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Seago aainagg AC aT i SOIR

V od & ay ( 0) 08 0S~3 <3 OS

for the Joy of Life No one can get real happiness out of life,

STRONGFORT The Perfect Man PUT YOUR ENGINE IN ORDER Don’t try to ride through life with an engine that rattles, knocks, misses and is likely to break down in the middle of the trip. care of your human machine as you do of your car. It’s a lot easier and less expensive to do. Nature will do the repairing, promptly, efficiently, systematically, if you give her a chance. her help you can free yourself from the chronic ailments that make your life a burden; develop your figure and muscles; vital organs, and get back the health, strength and vigor you used to have. Don’t make the mistake of thinking pill-eating will ever make you fit. is not put up in patented packages. dope may deaden your discomfort for a while, but it cannot aid the cause of your trouble which, 99 times out of 100, is some violation of Nature’s STRONGFORTISM Strongfortism is ‘‘The Science of the Normal.” It gets right down to bedrock in its treatment of It is Nature’s own way of rebuilding, revitalizing and rejuvenating the human organ- Laws. human ills. ism. I have spent my life investigating and studying out Nature’s methods. into the strongest man in the world. By themI have restored health and happiness to weak, sickly, anemic men and women in every part of the civilized world. build YOU up, so you are FIT to enjoy life, if you will follow my directions for a few months. : SEND FOR MY FREE BOOK *Promotion and Conservation of Health, Strength and Mental Energy”’ will tell you all about the Science of Strongfortism—what it has done for others and WHAT DO FOR way. own bedroom. Send for the book today—WRITE FOR IT NOW and use coupon below. IT'S FREE, but its real VALUE to you cannot be measured in dollars. Enclose three 2c stamps for packing and postage and I will mail you a copy at once LIONEL STRONGFORT Physical and Health Specialist 1306 Strongfort Institute YOU, no matter what your present condition is or what may have brought you to it. No medicines or drugs of any kind to take; no expensive apparatus to buy; no interference with your regular occupations—just Nature’s You can practice Strongfortism and secure its wonderful benefits by devoting to it fifteen or twenty minutes a day in the privacy of your however much money he may have, unless he is physically FIT. What are dollars toa man who can’t eat a square meal without discomfort? Where's the joy in an elegant home, if consti- ation, dyspepsia, bil- jousness or any other chronic ailment makes you wake up each morn- ing with a nasty taste in your mouth, an ache in your bones and a mill- stone in your chest? The real Joy of Life comes from the posses- sion of red-blooded health and _= strength PLUS sufficient money —from the ability to live as you want to live, eat what you want to eat and do the things that please you, without being reminded every hour that you have a stomach or a liver or a heart that has to be considered and coddled like an old woman. Take as good With strengthen all your Red-blooded manhood Druggist’s By them I built myself up By them I can and will IT WILL NEWARK, N. J-

----CUT OUT AND MAIL THIS COUPON---- Mr. Lionel Strongfort, Newark, N.J. Dear Strongfort—Please send me your book, ‘Pro- motion and. Conservation of Health, strength and Mental Energy,”’ for cents in stamps to cover mailing expenses. postage of which I enclose 6 I have marked (X) before the subject in which I am panes. ..Colds . Deformity . .Weaknesses ..Catarrh .. Insomnia ..Weak Eyes . Asthma .. Heart Weakness ..Falling Hair ..Hay Fever ..Short Wind ..Poor Memory . Obesity .Flat Feet .. Rheumatism .. Headache ..Constipation ..Poor Circulation .. Thinness .. Biliousness . Skin Disorders .. Rupture ..Torpid Liver .. Despondency ..Neuritis . Indigestion ..Round Shoulders .. Neuralgia ..Nervousness ..Lung Troubles ..Flat Chest ..Bad Habits .. Increased Height 0 ER ES. CS, 5 ER ery ir a1 eee ee eee ROR ems AF as a P< s7565 daa sech see RADEEES SEOs) ss chs speehecpuaesseaes

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How the Mechanic Can Keep His Tools Bright HE machinist or other metal- worker who uses steel rules, squares, bevel-protractors and other instruments that are graduated in inches and fractions, finds that they soon acquire a slight coating of rust upon their surfaces, which makes it difficult to read the markings. The rust is caused by perspiration of the hands, as well as by dampness in places where the tools may be laid away while the artisan is working in mill or factory. The method of keep- ing tools bright adopted by machin- ists, is to polish them frequently by means of oil and an old piece of emery-cloth, kept especially for the purpose. The tools are scoured from time to time, as is judged necessary. The graduations on these articles being shallow, it is not long before the tool is rendered useless by having its markings wear away as well as its edges and corners wear around. As an “ounce of prevention is worth a pound of cure;”’ the writer devised the simple appliance illustrated, which

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The illustration shows the oiler with the cover off, and the box with its roll of felt in position, ready for immediate use has given satisfactory service for over fourteen years. To construct one of these oilers, obtain a lacquered tin ointment-box of 22 in.in diameter and 5 in. depth (measured without the cover on). It can be bought for a few cents from a druggist. Also get a five-cent jar of vaseline. From a dry-goods_ store procure 10% ft. of red felt, if your box has the diameter mentioned; if it is smaller, it will require less of the felt. This material should be % in. wide. Spread a newspaper on the floor and rub the vaseline on both sides of the felt, then roll it up tight so that it will make a snug fit in the box. Put a pin through it to hold the roll together while it is being placed in the box. It is then ready for use. Lubricating oil can be used in place of vaseline if desired, but most oils contain a trace of acid which, small as it is, darkens the surface of

the tools. Vaseline, being derived from petroleum, keeps the surfaces bright and free from rust. To use the appliance, take the cover off and rub the greased felt on all sides | of the tool. Do this every day before | going home from work. Your instru- ments will always be bright, rendering the taking of measurements easier as well as resulting in greater efficiency 124

Popular Science Monthly Attach this Motor

New pleasures are open to the man who attaches a Lockwood-Ash Row Boat Engine to his row boat. It saves those long, hot, back-breaking pulls to the fishing or picnic grounds or the camp. It is simple, economical and practical and takes but a few minutes to install. Ask for our booklet and learn about the 30-day trial plan. Lockwood-Ash Motor Company 2013 Jackson Street Jackson, Mich.

ANCE the Newest Dances! YOU can learn Modern Ball- room Dancing now in your own home— no matter where you live— by the wonderful Peak System of Mail Instruction Courses on Fox-Trot, Waltz, One-Step and Two- Step include the last word in new Society dances— the Dardanella_ Fox-Trot, Bellefield One-Step, London Rocker Waltz and the Modern Two-Step. New Diagram Method: Easily and quickly learned. Thousands taught successfully. Suc- cess guaranteed. Send Today for FREE Information. at once for surprisingly low offer. WILLIAM CHANDLER PEAK, M. B. President, Peak School of Dancing, Inc. Est. 1880 Room 111, 821 Crescent Place, Chicago

Write (15)

| The Best Motor- hed Cycle Pe a Steffey Motor = Bicycle Because it costs less to run, is simpler and more reliable. Easy to attach to any wheel. Write, at once for prices. Agents wanted. Send stamp for circulars. STEFFEY MANUFACTURING CO. Department S. 5025 Brown Street, Philadelphia, Pa. Send 75 cents (no stamps) for All the Parts and Plans of our famous JERSEY SKEETER ~~ Greatfunto make it in less than 2 hours, and then see it fly 75 feet. 7 other models, all cloth wings. Airplane Circulet, 4 cent stamps. Most durable aeroplane made—Money back if not satisfied. NIFTY NOVELTY & TOY CO. Mail Order Office Newark, N. J JASSPINS-RINGS DIRECT FROM FACTORY TO YOU OUR NEW CATALOG WITH 600 OF THE LATEST UP-TO-DATE DESIGNS FREE. Cc. K. GROUSE CO. 12 Bruce Ave.. North Attleboro. Masa.

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VALUABLE INSTRUC- TION OR OUTRIGHT SALE OF SONGS TIONS TO BEGINNERS AND TELLS UNDER THIS SUCCESSFUL He Te TRUTH CONCERNING EVERY BRANCH CONCERNS OF THIS ESSENTIAL AND FACINATING PROFESS OF SATISFAC* ION-THE GREAT WORK ACCOMPLISHED BY THE POP ULAR SONG IN WINNING THE WAR IS ONCY AN INDEX TO THE MUG

Popular Science Monthly “Looks like your carburetor might | (7 see

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a ww Fe 3 n . SRSESESETA Wi

July, 1920 by saving time. Keep the cover on the box to exclude dust when it is not in use. Should a person possess a rule or square that has been allowed to accu- mulate much rust, chemical means may be necessary to remove it. Heat 1 qt. of distilled water and dissolve in it a quantity of chloride of tin in small portions. As fast as it dissolves, add more, shaking the bottle each time, until the water will not dissolve any more. This is called a ‘“‘satu- rated” solution. Place the rusty rule in a dish filled with the solution, and allow it to remain over night. Then remove it, rinse it carefully in water, wipe it dry with a cloth, and the job is done. The rule will be a silvery- white color. Grease it with the oiler to keep it in condition. The tin solu- tion should be poured back into the bottle.—W. S. STANDIFORD. When the Motor-Truck Engine Balked NE cool morning a certain farmer accompanied by his son was bowling merrily over the road with a good-sized motor-truck load of pro- duce he was taking to a city market. They came to a fairly steep hill and started up when the engine suddenly began to sputter and miss, and finally balked. Surprised, for not five min- utes before he had negotiated a much steeper grade, the farmer threw out his clutch and allowing the engine to idle, backed slowly to the foot of the hill and tried again. This time the engine acted as before, only the farmer was not quick enough at re- leasing his clutch and the motor stalled. He floated to the bottom of the hill again where both he and his son got out and looked the engine over. ‘Acts as though the gasoline might be low,”’ remarked the son. “It couldn’t be,’’ replied the father, “unless there’s a leak somewhere, for I filled the tank before we left home.” Nevertheless, they went carefully over the gasoline feed system but no leaks could they find. The carbu- retor was next examined to see if it was clogged by dirt or foreign matter and to make sure it was getting a full supply of gasoline, but no trouble of any kind could they locate. Exami- nation showed that the ignition system was apparently in good order. They then cranked the engine and after a few preliminary snorts it began to run evenly. Again they started up the hill, this time the son standing on the running board to the better observe the action of the engine. It worked fairly smoothly until the grade became steeper when, as before, it began to pop and miss, and then balked alto- gether. They backed to the bottom of the hill more puzzled than ever. A friendly truck driver came along, asked what the trouble was, and they explained. July, 1920 ee SA Ce Re ee Eee A re rill a |

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The only two- cylinder motor in the world to drive a bicycle Think of the week ends—the holidays and the vacation this summer that I am going to have with my TWIN-CYLINDER Johnson Motor Wheel it will take me any place where there is a beaten path— And I am going tod enjoy trips that I could not afford before, because this wonderful little power plant has converted my bicycle into a two-cylinder motor bike— Expense! Why it will travel 150 miles on a gallon of gasoline— That’s much less than railroad fare and cheaper than car fare. It is light and simple enough for anyone yet strong enough for any man, Interesting descriptive matter mailed on request. Write for it today.

THE JOHNSON MOTOR WHEEL COMPANY 906 East Sample Street - South Bend, Indiana

Our Sun Motors $ Cleartone Phonographs $4.00 to $200.00 Retail dry Dept. offers Needles 39c per thousand. roducers $1-80 to $6.16 ber eet.” Main springs 20c fo Tape cach. . Records prices. —_ Write for our 84-page catalogue, the only one of its kind in America, illustrating 33 different styles grote Pars. Explaining Try-Before-You-Buy Plan LUCKY 13 PHONOGRAPH COMPANY * Export Dept. 46G, E. 12th Street, N.Y. U.S.4. | HARRY A. SMITH, 306-218 North Wells St., Chicago, Ill. emonth $4 WILL BUY A Beautifully Reconstructed TYPEWRITER a With Every Modern Writing Convenience WRITE TODAY FOR ILLUSTRATED CIRCULAR

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SE CHANIC J ahs TIRE SURGEON < Owns *6000 Home has substantial bank account; does $100 business daily; ready to start second and larger Tire Surgery Station. This is record of John W. Blair, Ohio. Two years ago he was practically broke. Today he’s successful. Weteach you

,000 in 9 months, etc. Can be EQUALLED or SURPASSED by you Earnin Haywood’s new Tire $200 to $500 Month MSS oi ery isascientific method of rebuilding worn, r , threadbare casings. Makes them like new. Adds 4,000 to 5,000 miles to old tires. Millions of tires used; t! sande peematuesdy discarded —field is unlimited. Our instruction is thorough and complete — free, We give you a diploma that fits you for business management — shows you are ble in every phase of Surgery. Big openings everywhere—cities, small towns or villages. You are looking for an unusual money-making opportunity. Here it Is! : SEND THIS COUPON

— investi ; read and learn what others every = Write 1 Mr. M. Haywood, President, Leif have doye—our FREE book and circulars ~ A MAYWOOD TIRE & EQUIPMENT CO, ng. Simply sign your name to coupon. it now! a 1289 Capitel Ave., indianapolis, ind. ood Tire & Equipment Co. A tm Tt Eee ew dense tn —s erarianenes Address 125

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Mad RE IS 1 Pa RS oe => Learn Drafting Employers everywhere are looking for skilled draftsmen. They are offering good salaries to start with splendid chance 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 to do. There is an easy delightful way in which you can learn right at home in spare time. For 28 years the Inter- national Correspondence Schools have been giving boys just the training they need for success in Drafting and more than 200 other subjects. “Thousands of boys have stepped into good positions through I. C. S. help, but never were opportunities so great as now. Let the I. C. S. help you. Choose the work you like best in the coupon, then mark and mail it. This doesn’t obligate you in the least and 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. Soe eee eee oe == TEAR CUT HERE cee cee woe oe oe « BOX 7685, SCRANTON, PA. Explain, without obligating me, how I can qualify for the position, or in the subject, before which I mark X. ELEOTRIOAL ENGINEER SALESMANSHIP Electric Lighting and Kys. ADVERTISING Electric Wiring Window Trimmer Telegraph Engineer Show Card Writer Telephone Work Sign Painter MEOHANIOAL ENGINEER Railroad Trainman Mechanical Draftsman ILLUSTRATING Machine Shop Practice Cartooning Toolmaker BUSINESS MANAGEMENT Gas Engine Operating Private Secretary CIVIL ENGINEER BOOKKEEPER Surveying and Mapping |Stenographer and Typist MINE FOREMAN or ENG'’R Cert. Pub. Accountant STATIONARY ENGINEER Marine Engineer Ship Draftsman ARCHITECT Centractor and Rullder TRAFFIC MANAGER Railway Accountant Commercial Law GOOD ENGLISH Teacher Architectural Drafteman Common School Subjects Concrete Builder CIVIL SERVICE Structural Engineer Railway Mail Clerk PLUMBING AND HEATING Sheet Metal Worker Textile Overseer or Supt. OHEMIST Mathematics AUTOMOBILE OPERATING Auto Repairing Navigation Spanish French Italian AGRICULTURE Poultry Raising Oooo Name Present Occupation Street and No City Stato. Canadians may send this coupon to International Correspondence Sch 7-26-19 ls, Montreal, Canada “Looks like your carburetor might be out of order,” he suggested. “It couldn’t be,’”’ stoutly defended the son, who had studied its adjust- ment. ‘“‘That make of carburetor doesn’t suddenly get out of order. Why, five minutes ago it worked per- fectly, didn’t it, father?” “Yes, coming up Pepper’s hill it couldn’t have worked better,’ his father confirmed. The truck driver was unconvinced, but after examining the carburetor acknowledged he was unfamiliar with that make or its adjustment. Then feeling he could be of no further help, he drove on. The truck driver’s reference to the carburetor set the son to thinking and he remarked to his father as they were starting up the hill again and the engine began to repeat its pre- vious performance, “It acts just like it does when it’s cold, before it gets thoroughly warmed up.” As the engine continued to balk, he got out, lifted the hood and felt the carburetor. “Why, it’s cold,” he exclaimed ex- citedly. He gingerly felt of the hot air intake feed pipe and found that this also was cold. The scent was growing warm, and following the hot air pipe to the heater on the exhaust pipe, he discovered it had jarred or shaken loose at the connection, leaving an opening so that cold air could enter, consequently no heated air was de- livered to the carburetor. “There’s the trouble, I’ll bet,’ he said. Reconnecting the separated parts was the work of a few moments. Then after allowing the engine to run a few minutes, or until thoroughly warm they mounted the hill with ease. All of which proves that “hot air” is a very necessary element to the successful operation of a loaded motor- truck on a cool morning, especially in these days.—EpD. HENRY. How to Make a Draftsman’s Centering Instrument HANDY draftsman’s center that [ \ will not injure the -drawing is illustrated in the accompanying pic- ture. It is simple, and can be made Why buy a centering instrument when you can make one from material on hand 126 Popular Science Monthly Get out into the open—have health- ful sport on Amer- ellie! te and est - built bicycle, the Black Beauty. Write for our catalog, select your model from our 40 styles and tell us. We'll ship at once. To make the wheel yours, pay a small deposit, then $1 aweek (or$5a month), Made at our own big factory. Wholesale direct price. 18 Wonderful Features The Black Beauty is built of the’ highest grade materials by the largest exclusive bicycle house in America. Its equipment includes $10 Firestone Blue Non-Skid Tires; New Departure Coaster Brake; moto-bike saddle and pedals; handlebars that are triple plated over copper to prevent rust, etc. Seamless steel tubing racy lines, dazzling nickel and enamel finish. FREE! Repair Kit, Tool ——umae Case and Stand 5.year guarantee and six months ac- cident insurance. Take advantage now of = offer of oe wonderful Black uty. m m: Write for catalog today. aiid Sundries Get our factory prices. - : Lowest in the country. Tires, rims, bells, lamps, ete. Send for Free Sundries Catalog. Haverford Cycle Co, Dept, 387 Philadelphia 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 i. or pads. ; MR. C. E. BROOKS Brooks’ Rupture Appliance Has automatic Air Cushions. Binds and draws the broken Fagg together as you would a broken limb. No salves. No lies. Durable, cheap. Sent on trial to prove it. Protected by U. S. patents. Catalog and measure blanks mailed free. Sendname and address today. Brooks Appliance Co., 255C State St., Marshall, Mich, MakeYour Bike a Catalog in colors Y’ The low cost Shaw Attach- ment = ‘wae pao Easily put on. No special tools or knowledge nec- a, Write at Shen for Free Book, also about Shaw Motorbicycle, a complete power bike at bigsaving. SHAW MANUFACTURING CO. Dept. 467 Galesburg, Kansas “BOWLEGSandKNOCK-KNEES td UNSIGHTLY W SEND FOR BOOKLET SHOWING PHOTOS OF MEN WITH AND WITHOUT The Perfect Leg Forms PERFECT SALES CO.,140 W.Mayfield Ave., Dept. 45, Chicago, Ill. Agents—$50 to $70 a Week Easy outdoor work applying the Century Process to automobiles and furniture. Every auto owner is your prospect. Three to six autos can be treated per day, at from $5.00 to $10.00 per auto. Weteach you and put -you in business. Complete particulars free. Write at once. ‘CENTURY PRODUCTS .CO., : Dept. F. Cincinnati, Ohio Wrestling Book FRE = to be an expert wrestier. Know scientific AG er are Bees &a thie popufar school end carn by m won Frank Gotch and Farmer Burns aX off . is \ ES ; 8-120 Ramee Bldg., Omaha, Neb -_ ee , How to Make Wireless Instruments A little book that fully describes the construction of spark wireless instruments and pgperetes. Just the thing for the amateur. Illustrated. Price, postpaid, 25¢ Book Dept., Popular Science Monthly 225 Wet 39th St., New York City Popular Science Monthly

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“= @LRSssF oe seo | a sity N wn ,a ay July, 1920 in a minute or two of time. A- tri- angular shaped piece of heavy paper or bristol-board is used and a notch is cut on a previously drawn center line. The center line is used to line up the device with a T-square and the other notch is used to center the device on a center line of the drawing underneath. Near the end of the cardboard triangle on the center line carefully push a thumb tack through from the other side. Place the thumb tack head down on the drawing, having first drawn pencil lines to show where the radiating lines intersect, and either locate with the eye or test with a triangle. Clothes-Pins Arranged to Serve as a Tool-Rack O keep. the small tools hung up and out of the way is not always an easy problem but if you can find some old clothes-pins and a board, a rack for holding tools like screw- drivers, files, chisels, etc., can be quickly made, and will prove a handy asset for the work shop. Cut off the Clothes-pins with their heads of the heads cut off and set * in a board make an ——— ~ excellent tool-rack Close to the end as possible. Then mark a straight line along the middle of the board and bore holes along it, slanting slightly downward. Into these the ends of the clothes-pins should fit tightly. Smear the clothes- pins with glue and force them into the holes. When they are dry, fasten the rack over the bench and the small tools will always have a place. N—CLOTHESPIN An Old Film Will Make an Excellent Duplicator N old photographic plate or film, either exposed or unexposed, will make an excellent duplicating device capable of making twenty to thirty copies of typewritten or hand-written originals. Obtain an old plate or film and soak it for several minutes in lukewarm water. Then lay on a flat surface and remove the excess water by using several pieces of newspaper as a blot- ter. When the surface has become sticky so the paper peals off, then lay the previously prepared copy face down on the plate and smooth it gently by rubbing the back with your hand. Allow it to stay on for about a minute and then remove it. Blank pieces of paper are now laid on, smoothed out, and immediately peeled off. These will be found to. have a perfect copy of the original. It is impractical to remove the old copy to make another as the ink eats through the film.—Victor H. Topp. g¢sththeé. (nnn Pe ce oa engage ARR ESET APR a8 \ TRADE-MARKS COPYRIGHTS PATENT SPECIAL OFFE PATENT ABLE NATURE Before disclosing an invention, the inventor should write for our blank form **Evidence of Conception.’’ This should be signed and witnessed and if returned to us to- gether with model or sketch and description of the inven- tion, 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 Sent FREE on Request Contains full instructions regarding Patents, Trade-Marks, Foreign Patents. Our Methods, Terms, and 100 Mechanical Move- ments illustrated and described, Articles on Patent Practice and Procedure, 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. SPECIALIZATION Our Staff The field of invention is so fast that it is impossible for any one man to become an expert in all the different classes of invention. Only those practically 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. This work will receive the benefit of skill and experi- ence acquired by a long and successful practice. 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 thoroughly is evidenced by the many unsolicited letters of commenda- tion 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 scaunaie of our business we have established for the benefit of our cliente Branch Offices in New York City, Philadelphia, Pa., Pittsburgh, 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, particularly as the branch offices are in constant touch with the Main Office and fully equipped to handle patent businesain all its branches. Highest References—Prompt Attention—Reasonable Terms. iXi at Ti hy i " E 4 i iW VICTOR J. EVANS & CO. Patent Attorneys New York Offices 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. q ——-- - ee ee L. 127

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TO LEARN HOW TO SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. Tells our Terms, Methods, etc. Send model or sketch and description of your invention and we will give our opinion as to its prccctress------ patentable nature. RANDOLPH & CO. IF YOU HAVE AN Pp AT FE Re T INVENTION and DESIRE 130 F St. N. W., Washington, D. C. | |PATENTS F YOU HAVE AN INVENTION | ee which you wish to patent you can write fully and freely to Munn & Co. Free Book on Patents for advice in regard to the best way Before applying for a patent write of obtaining protection. Please send = for a Free Copy of our book sketches or a model of your invention i) ‘Howto va te a Patent,’ * which sas : Ra I | contains valuable information an and a description of the device, explain se advice to inventors. It tells how ing its operation. to secure Patents. Send a model All communications are strictly confi- or sketch of your invention for d 1. O ; di ' our ‘Evidence of Conception” ential. Our vast practice, extending form and our opinion of its over a period of seventy years, enables patentable nature—Free. Twenty na ts nny many cases to adiviee in regard to years’ experiencein patentmatters. | vp. 5 Write today for your patentability without any expense to FREE BOOK. the client. Our Hand-Book on Patents is sent free on request. This explains our methods, terms, etc., in regard to y Patents, Trade Marks, Foreign Patents, etc. If you are a reader of SCIENTIFIC | AMERICAN you are probably aware of the fact that it has a special appeal to the inventor. Each issue OUPR RPO EU PORE SEER ERE SEE SESESER ERE ES EGER EERE E ES SES, PATEN TS Trade Masks Send sketch or model for actual search and report. Write for Book- let of instructions on patent practice and procedure. Prompt personal service.... Geo. P Kimmel Patent Lawyer ; | contains a description of a : large number of recently pat- - ented inventions. Pending pat- ‘i ent legislation as well as the Her : } seererero most recent rulings of the i] Patent Office and the courts HELE are considered in its columns. Ii MUNN & CO. SOLICITORS OF PATENTS THEE 683 Woolworth Building, New York i} 624 F Street, Washington, D. C. HE Tower Building - Chicago, Ill. Hobart Blidg., 582 Market Street, San Francisco, Calif. Ohpareerereeteaaeetan ATENTS PROCURED and TRADE-MARKS REGISTERED Twenty Years’ Experience. Instructions and Terms on request. ROBB, ROBB & HILL, Attorneys at Law Specializing in Patent and Trade-mark Practice exclusively 840 McLachlen Bldg., 1336 Schofield Bldg.,, foe ROR OUUS MES STEUCCTEOUU LOU CER PO UUPCURE E CEUSUCOC COC UREU SEES EUAtORC EE COU eRe lew - - - - ~ .- - - - - - - _ - - os - - . ~ - ~ - 7 ~ - - Washington, D. C. Cleveland, Ohio : 39-H Loan and Trust Building, Washington, D.C. - f representative a OPULAR SCIENCE MONTEREY SU RSSE SES ECES PSE SSE RSGCSE OR SE eet tee cone 225 ERAGE | 7 DIAMONDS (mmm WATCHES eas | (Fey | Eas Dy, ammo + LITT ri iid Send } Catalog + There are 128 pagesor Diamonds, Watches,Jewelry, /7/ >.» home Green Sd all priced unusually tow. | X , ie Ei White and Yellow fj 1987'S BRos.aca i Saserreiges tea H , Loo Solid Gold, very . special at $85, $100, © $1 ag oe Credit \————d) Stores in Leading Cities Dept. §.37§ 108 N. STATE ST., CHICAGO, ILLINOIS 128 Popular Science Monthly A Bench-Clamp for the Amateur Carpenter : ie bench-clamp is a simple tool to make, yet it is a very excellent device. It is made from odd bar stock; the old square axle of a light buggy furnishes excellent material. The leg is bent at right angles. The ~ PIVOTED ARM & $ Vat "FLAT IRON? [—] [| If you have an old buggy-axle lying around, you can turn it into a_ useful bench-clamp section passing through the bench is 2 ft. long, and the section to which the U-piece is riveted is 10 in. The U-shaped piece is made of % by 1-in. iron. The pivoted arm is forged from a piece of the axle into the shape shown. The strip of iron set into the plank on the bench is a piece of %- by 1%-in. iron obtained from an old heavy wagon wheel tire. This strip is fitted up to take the clamp at various parts of the bench. The square holes are made by drilling a hole, filing it square, and then filing a key-way for the taper- wedge key. By prying up the key, the clamp is quickly adjusted for any height and by a light blow upon the key, it is secured.—C. H. WILLEY. How to Lock Your Tool-Box Securely © HE accompanying illustration shows a combination lock for a tool-box provided with a drawer. A door-bolt here takes the place of a second lock. The door-latch is screwed to the inside wall of the tool-box, the bolt passing through a hole in the bottom TOOL-CHEST ——3__ I t DOOR-BOLT oe aeat DRAWER at H- ==) Tools can be stolen from the drawer of your tool-box. Why not give it a lock too? of the base. To lock the box, the bolt is first anchored, holding the drawer firmly fastened from the inside, then the tool box is locked by the key in the usual way.— ERNEST SCHWARTZ.

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eS [ll ~~ _ ero 1e ans |, tal ‘ “wy Fh It er on he July, 1920 DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CQN- 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 of inventors all over the United States and_Canada in the ad- 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 pay a request. Ask for them,—a post card will do. PATENTS ANDO 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘Evidence of Conception.” To the Man With an Idea } I offer a most comprehensive, ex- 4 perienced, efficient service for his prompt, legal protection and the } development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladly furnished with- out charge. My. experience and familiarity with various arts, frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet of valuable information and form for properly disclosing your idea, free on request. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C. 2276-D Woolworth Building, New York City THE PATENT INSTITUTE EJ FOR INVENTORS PATENTEES INVESTORS AND MANUFACTURERS THE PATENT INSTITUTE 9TH. & GRANT PLACE WASHINGTON, D.C. mz—-ummz—-HzM| An Inexpensive Typewriter Cleaner HEN the typewriter keys begin to work with difficulty,it is a sure sign that the old oil on the delicate bearings of the type bars has become gummy, ana no amount of re-oiling will do any good; unless, of course, the bearings are first thoroughly cleaned. To do this easily and without dis- manteling the machine, construct a cleaner of the simple squirt-gun type, as shown in the cut. It is made as fol- lows. Procure a 34 in. by 6 in. pipe nipple, wrap a piece of fine sandpaper around a round file, and thoroughly clean the inside of the pipe of all scale; next get a 34 in. pipe cap into the center of which drill a 1/16 in. hole. ig HOLE fut IRON WASHERS When your typewriter keys get dirty and begin to work with difficulty this home-made gaso- line squirt-gun will clean them Screw this tightly on one end of the nipple. You now have the barrel of the pump made, and you can proceed with the plunger. From a piece of 4 in. rod cut a piece 12 in. long, form a hand-grip at one end as shown, thread the other end for a distance of about 1 in. and screw down a 4 in. nut, place a 14 in. washer on this end and on the washer place three washers cut from sheet rubber or leather; put on the other 14 in. iron washer and nut, tension the soft washers by screwing down this nut till the plunger fits tightly in the barrel. Having strained some _ gasoline through a piece of. chamois skin or old felt hat—to be sure that no water is in it—and having placed the typewriter out in the yard, or out in the open far removed from any flame—push the plunger to the bottom of the barrel and submerge it in the gasoline; then draw it up and squirt with a hard, quick push, which will throw a fine, hard stream against the type-bar and other bearings. Allow the machine to dry about five minutes, and oil it thoroughly. To do this you will need a piece of very small copper wire about 8 in. long; form a loop at one end 1 in. in diameter, flatten the other end for about an eighth of an inch; pour a little oil into a saucer, or some other clean receptacle, dip the flattened end of the wire into this. A small quantity of oil will adhere to the point, and apply this to the various bearings. Wrap both these utensils in a clean cloth and put them away for future use—you will never want to be without them after once using them, for they will be found invaluable for this kind of work.—Roy C. BRADBURY. 129 BIG PROFITS IN A FAST GROWING BUSINESS Wouldn’t you like to make more money, and be independent? Wouldn’t you like to get all the profits by owning your own business? To be sure you would; then here is the opportunity. 18,000 IN ONE YEAR Tire Rebuilding is one of the most profitable fields of the Automobile Industry; $18,000 made in one year by a man who started in a small way. you CAN DO IT TOO Vanderpool Tire Rebuilding Plants have made big money for ambitious men. One firm writes ‘‘Our plant is very satisfactory, we got our money back out of the first month’s profits’. Many have said that after working on several makes of Vulcan- | izers, they chose the Vanderpool, when going into business. Names on request. LARGE PRODUCTION—BIG PROFITS The Vanderpool 5 Cavity Plant will rebuild and retread 9 Tires and 5 Tubes at the rate of $30 an hour. Any one or all of its parts can be shut off making it economical and speedy. The Vanderpool can be furnished in all sizes and we will design special plans for equipping your shop whether you start in a large or small way. DO IT NOW—DELAY LOSES MONEY Write for price list and Tire Rebuilding Manual full of valuable information. Price 25:. Vanderpool Vulcanizing Co. Dept. 7-F SPRINGFIELD, OHIO wo te CAN YOU think of a simple, practical idea that will fill one of the many ree quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed RiGut Now. Your brains can help. Send to- day for our great new book—“‘Invene tions and Trade Marks, Their Protection and _ Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, too. A postal will do— it is free. We help our clients, PATENTS SESS 7 wens nene others possess. — For SALE F REE pasos es In INVENTION And wion MANUFACTURING SUPPLEMENT. AMERICAN INDUSTRIES, INC. 201 Patent Dept., WASHINGTON, D. C. Published for the Man with an idea Send for free sample copy. One year’ssub- i @cription 50c. The Bok for Inventors and SixTn Gorrionw By return mail FREE. write LACEY & LACEY Dept.M Washington. DC SIXTH EDITION

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A ee ee —a ea Forest Trees Come to Aid of Radio Men * The forest ranger has a valuable ally in the new radio-telephone AST year, the Federal Forest Service thoroughly tested the radio-telephone in the western national forests, and ascertained that under average conditions in those regions, the wireless method of communication used being about 50 miles. During the current year 42 sets have been estab- lished at various points in the national forests of Wyoming, Montana and Oregon. With great labor, the storage batteries and other equipment have been packed into the mountains on the backs of forest rangers. At the present time a recently invented gaso- line engine is being used for re-charging the batteries at some of the camps, thereby reducing much of the hand labor formerly necessary in conveying the dead batteries from camp to town. Last year the War Department, ‘through its flying schools in Southern California aided the Forest Service representatives in patrolling national forests in the Golden State in the fire location work. This season the work will be continued and extended into northern Wyoming, Idaho, and Montana. Twenty forest rangers are now attending ground schools at one of the army camps in order to become familiar with the flying activities so that in their ground work in coopera- tion with the airplane patrol service they can render efficient service. It is planned to utilize the radio-telephone as a means of communication between Packing wireless telephone equip- ment into the mountains. When the trail gets too steep for the mule the rangers carry the equipment was more satisfactory and much cheap- er than the installation and opera- tion of the ordinary telephone system. For example, two complete wireless stations were installed with a talking range of 60 miles, for $3,000. This included the power plant and all accessories. A telephone system of similar character and length would have cost over $5,000 at that time. The radio-telephone is easily installed and is simple to operate as soon as the rangers become familiar with its technique. In one instance several months after a certain set was placed, two green hands who previously had been uninformed about wireless tele- phony were able to expertly take and send messages. At each set two suitable trees are cleared of boughs and branches and wires are stretched between them to serve as antenna. The storage batteries and other equipment are usually placed in a tent which is re- served as the communication center of the camp. The communication area to each set has ranged anywhere from 10 to 300 miles, the average distance from the set where portable outfits are Showing how a forest ranger operates his radio-telephone the airplane patrols and the rangers below to facilitate the transmission of information about fire outbreaks. Sug- gestions now before Congress are that the 154,000,000 acres of national for- ests be henceforward policed by flying machines. It is estimated that 90 planes would be required for such ser- vice and that the annual saving in valuable timber and grazing land would more than pay expenses. The foregoing shows how the wire- less telephone is invading the forests of America. The other important appli- cations of radiotelephony must not, however, be lost sight of in the natural 130 Popular Science Monthy Two tree-tops are cleared of limbs and the antenna wires strung between them He is receiving the first wireless tele- phone message ever sent in national forests interest of new developments. As examples we may mention its uses for ordinary ship-to-ship and ship-to-shore business traffic, for communication with long-distance railway trains, and in lighthouses for assisting ship navi- gation in fog. We are on the thresh- old of great developments in this direction. Two Radio Records WO long-distance radio records are arousing special interest among operators of low-powered stations. They were made by the sister ships Colombia and Venezuela, of the Pacific Mail Steamship Company, while on their way home from Asia, working with the Inglewood Navy Radio Station which is located near Los Angeles. Each ship was equipped ‘with a 2-kilowatt radio set. Inglewood has two towers, 325 feet high, and is equipped with a 12-kilo- watt federal are apparatus. When the Colombia was 4,100 miles from our coast she first got in commu- nication with the Inglewood Station. For a real long-distance radio record for low-powered stations, however, the Inglewood operators and those on the Venezuela deserve the palm. On November 11 the Venezuela, about seventy miles out from Yokohama and 5,900 miles from the Inglewood Station, got through to the Inglewood Station and exchanged a number of messages. Radio experts say this is the record for low-powered stations. A 2-kw. set is ordinarily good for a maximum distance of 400 miles during the day and 1,000 miles at night. The remarkable distance covered by the Venezuela 2-kw. set would appear to indicate that a new type of equip- ment was involved, but this has not been stated.—J. W. K. a RET ae a - Hm 4 © 6 |HA ® Ha Oo > = - ht ft pete

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July, 1920 What’s Happening to the Amateur’s Decrement? HE answer to this question is that his decrement is vanishing. Many amateurs are now using continuous wave sets which involve vacuum tubes. Some are using quenched gaps and are sending out wave trains that are very nearly steady. Each wave is only a little weaker than the pre- ceding, that is the decrement is small, and the interference is not nearly so troublesome as it was with the old spark sets. The smaller the decrement the more amateurs can live in peace and harmony within a given radius, for Early type of wave meter with = addi- tional coil for extend- ing its wave length range the more messages they may transmit through the ether without interfering with each other at the various receiv- ing sets. Mr. Amateur with the high powered set, are you doing your share? There are two ways to find out. One is to stand by for complaints and comments from others who are trying to carry on communication at a wave length very near that which you are trans- mitting. The other way is that of self-analysis of which we hear so much today. For this you need a wave meter which you can either buy or make. Recent improved type of wave meter with the coupling coil inclosed in the case It can be made as follows: make up a tuned circuit, containing a fixed in- ductance coil and a variable condenser, which has.a tuning range on both sides of the wave length in which you are in- terested. Connect a small sensitive hot wire ammeter like that of Fig. 1 wonderful Natrometer outfit which we Radio Telegraphy and Telephony Can Now Be Mastered at Home By Marvelous New Method You can now learn Wireless Telegraphy and Telephony in spare time at home, quickly and easily by mail, through the famous Home Study Course of the National Radio In- stitute and with the help of the will send you. Then you can travel if you want or locate in land station work near your home. This Fine Natrometer Sent to Every Student We send you this wonderful set to use while taking our Home Study Course. It becomes your personal property on completion of the course. The Natrometer automatic- ally sends you messages at varying speeds as you would receive them from distant wireless stations. Special Privileges to National Radio Institute Students Combination course in Wireless Telegraphy and Telephony for price of one course; Post Graduate Course free, at Washington school, if desired; Complimentary membership in N. Relay League with handsome blue and gold membership pin; Handsome diploma suitable for framing; Complete automatic Natrometer outfit and carrying case; Personal help in securing position and endorsement of institute officials. SEND FOR FREE BOOK Send the attached coupon TODAY for free copy of our valuable and interesting book ‘‘Wireless The Opportunity of Today,”’ telling how we help you win success in Wireless. NATIONAL RADIO INSTITUTE America’s First and Foremost, Established 1914 Dept.'241, 14th and U. Streets, Washington, D, C, Salaries Up to $15,000 a Year Our graduates start work as Senior Operators at $125 a month with all living expenses paid. Advancement to high positions is rapid with bigger pay, as follows: Radio Engineers $2,500 to $15,000 a year; Radio Aids $6 to $15 a day; Aerial Mail Service $1,500 to $2,400 a year and 10% bonus; Radio Inspec- tors $1,200 to $3,500 a year. Our Graduates are guaranteed positions upon securing their official license after taking our course. Send Coupon for FREE Book ecesee SS Bees eff 2e8aeestessaseesacaany National Radio Institute Print Your Name and Dept, 241, 14th & U Sts., N. W., Address Carefully = Washington, o.c. 6 Send me your Free Book ‘‘Wireless The Opportunity of § Today.” Tell me about your famous Home Study Course , in Wireless Scearaohy and Tepe our Post Gradu- s ate Course—membership in the N.R. 1. Relay League and * your Special Instrument Offer. s SMO he ooo ee wai a ie Oe nee a ae 2 IE Kale. 2. 5.2, Sse a0 ig tia GA eine 4 ee Re ea aaa ae - CRG wiki isin ete ns eee aio we ee dcigh wis States os :- o0% a Wireless Transformers Will give you a greater sending range. 1,600 miles have been covered with a 4% K.W Write for Bulletin. x WARREN, OHIO mail SPaNisH Salesmen, Bookkeepers, Clerks, Stenographers, can increase their earning power thru a knowledge of Commercial Spanish. The South American field, now opening up on a tremendous scale, offers splen- did inducements to men and women who understand Sprnish. The LaSalle Home Training Course gives i you a mastery of Spanish in a surprisingly short time. Instruction can be carried on during your spare time without interference with regular work. Every week you let hours slip away in which you could easily learn Spanish and qualify for a respon- sible position with some large American exporting firm desirous of increasing their Latin-American business. Write for catalog com letely describing our Home Study Plan and the cpportunities open to those having a knowledge of Commercial Spanish, LaSALLE EXTENSION UNIVERSITY, Dept. 7 Chicago **The Largest Business Training InstitutionintheWor PSM. Be An Amateur JaesKeb Comm @) eich uct me) a Set up your own Wireless Station and “‘Listen-in’’ on radio news from everywhere. Anybody can do it. Our new book, ‘‘How to Set Up An Amateur Radio Receiving Sta- tion” tells what you need, how to get it, how to set it up and operate it. Explains wireless so everyone can understand and gives infor- mation about Radio ‘work. Send 10 cents in stamps now and get a copy. DE FOREST RADIO TEL. AND TEL. CO.. 1393 Sedgwick Avenue, - New York City “ASK ANYONE WHO HAS USED IT” Brandes Wi t randes Wireless Headse TR [AL Bey? Brandes Su- . perior Headset and , OFFER" it critically for P ten days. Then, if it doesn’t come up to our claims or your expectations, return it and your money will be cheer- fully refunded. ‘Test it—com- pare with others—for sensitive- ness, clearness, distance. Prove for yourself the fine the ‘‘matched tone.”” The two diaphragms toned exactly alike, strengthen the signals and pre- vent blurring. Used by many U. 8. Gov't experts and experts abroad; by colleges and techni- cal schools; and by profession- als and amateurs everywhere. Send 4c for Catalogue R * BRANDES, inc., 32 Union So. Room $3, Now York, U. S. A. WIRELESS RECEIVER SPECIALISTS “Superior’’ Set 2000 ohms would. Adopted Schools. 4 styles. _____. _.~ THERE'S PIONEY INIT” cen ie-LEARN TELEGRAPH Y= one _.. _- _MORSE AND WIRELES ) TEACH YOURSELF unlimited Morse or Continental messages, at any speed by v: oe Seve. and leading Universities, Colleges and Telegraph atalog OMNIGRAPH MFG. CO., Dept. H., 39 Cortlandt St., New York. in half usual time, at trifling cost, with the wonderful Automatic Transmitter THE OMNIGRAPH. Sends .. just as an expert operator

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~ raewene pe aS ae renames: em Use Your Head The man who succeeds is the man who uses his head. These practical books will put you on the road to success. Means Money to You The most valuable techno-chemical formule book published, including over 10,000 selected scientific, chemi- cal, technological and practical recipes and processes is the Twentieth Century Book of Recipes, Formulas, and Processes This book of 800 pages, gives thousands of recipes for the manu- facture of valuable articles for every- day use. Hints, helps, practical ideas and secret processes are re- vealed within its pages. It covers every branch of the useful arts and tells thousands of ways of making money. Cloth binding. Price, post- paid, $4.00.’ Getting a Good Job By Charles R. Barrett A practical solution of the problem of fitting the right man to the right place, based upon the experi- ence and practice of some of the most successful employers, employment managers and employment agents in the country. It is specially designed to show the employe how to utilize his training and experience to the best advantage when seeking employment or promotion. It explains the basis upon which men are hired or promoted, describes successful methods of going after a job, and gives much practical informa- tion regarding advertising for a situation, writing letters of application that bring results, and making a favorable impression in a personal interview. Chapters include such subjects as: “The Right Place,” ‘‘ Training and Experience,” ‘‘ Personality Counts,” “Salary Expected,” “Going After the Job,” “Applying by Letter,’’ ‘‘Employment Agencies,” “Applying in Person,’”’ “‘The First Job,’”’ “‘The Employment Manager” and ‘‘ Winning Promotion.” Your chance of promotion—Capitalize your record— Selling out to a competitor—Trial promotions— Employers pay for efficiency—Get your employer's advice—Lines of promotion. Price, postpaid, $1.15 Automobile Repairshop Shortcuts 1500 Kinks This book contains over 1,500 time and labor saving methods and devices that have proven ex- ceptionally helpful in repairing or adjusting engine clutches, gear-sets, running gears and bodies, etc., and in managing and equipping shops. Mere gim- cracks and novelties that have no practical value have been omitted. Every word is simple and to the point; and the whole book is gotten up with the idea of enabling the good mechanic to become a better one by utilizing the experiences of others who may possibly have devised quicker methods of doing the work than he is now using. Progress comes largely from experience, and here is the opportunity to study the methods of over five thousand experts who were all striving to find a better way to do some job and to shorten the time required to do it. More than 1,500 Price, postpaid, $3.50. Make Perfumes— Make Money Perfumes and Cosmetics, Their Preparation and Manufac- ture. By G. W. ASKINSON. A comprehensive treatise, in which there has been nothing omitted that could be of value to the perfumer or manufacturer of toilet preparations. Complete directions for making hand- kerchief perfumes, smelling-salts, sachets, fumigating pastiles; preparations for the care of the skin, the mouth, the hair, cosmetics, hair dyes and other tcilet articles are given, alsoa detailed description of aro- matic substances; their nature, tests of purity, and wholesale manufacture, including a chapter on syn- thetic products, with formulas for their use. A book of general, as well as professional interest, meeting the wants not only of the druggist and perfume manufac- turer, but also of the general public. Nearly 400 pages, illustrated. Price, postpaid, $5.00. illustrations. Cloth binding. Book Department POPULAR SCIENCE MONTHLY 225 West 39th Street New York into the circuit as shown below. wave meter is now complete. The condenser and thermal instru- ment should be mounted in a box and the coil attached to the top of the box on an arm or pivot. This permits the coil to be rotated so as to vary its coupling with the circuit under meas- Your S| When this hot wire ammeter is connected as shown in diagram we have a wave meter urement without having to move the box. The leads to the coil should be separated about an inch and tied to keep them always the same distance apart so that their capacity does not change. The next step is to calibrate the wave meter. The simplest way in- volves getting some friend, who has a good wave meter, to send for you. Or ask some strong station just what his wave length is. To calibrate, you couple the wave meter coil to your antenna coil and tune in your friend. The hot wire ammeter will not be sensitive enough so leave it.in circuit but connect your detector across the condenser of the wave meter and receive in the ordinary way. Mark the setting of the condenser and then look for some other wave lengths. Of course if your receiving set is calibrated you need only to switch the wave meter circuit over as a substitute and tune it to receive the same station as you received on your regular set. The chief use of the wave meter is to check the frequency of your own trans- mitting set and to tell you how to adjust it so as to have a small decre- ment. For this purpose couple the wave meter coil to your antenna coil and see what setting of the condenser gives a maximum reading of the ammeter. This gives your wave length. If the ameter reading does not change much as you vary the, condenser it means, of course, that your resonance curve is flat, that is that your dec- rement is high and troublesome to others.—TEN BROEKE. How to Use Your Wave Meter . F you don’t want to be rated as an “etheric pirate,’”’ to use Dr. De Forest’s phrase, you can protect your- self and your neighbors by the proper use of your wave meter. My method can be learned by an ordinary operator in a half an hour or so. First couple the primary and second- ary of your transmitting set very loosely and then tune. Now couple your wave meter coil to the secondary of your transmitter. If you are not sure what loose coupling really means separate your primary and secondary 132 Popular Science Monthly WARNERS “scromatic» eo @ eo ae = with wea’ this arm is unsu FREE LESSON OFFER An authority has prepared for us, @ set of six lessons on the Art of Pistol Markmanship. These lessons are of marvelous value in the use and care Of a Warner“‘infallible’’ Automatic. Write today for illustrated cir] cular and terms of Free Lesson ere “THE 4s PISTOL , That QuICK Shoots and Hits SHOTS ~ the Mark” fe} d “ ee oan u och S18 32 larner “* infallible.’® Get the best and save CAL. at least $ Get a Warner “‘Infallibie’”’ Automatic and teach the women how to plug the bull’s eye. Target shooting is intense, exciting sport Excellent training for nerves and eyes. Teaches self-reliance, contidence and familiarity ns. What a Shooter Says :‘‘Y our ‘infallible’ Automatic Pistol is all that you claim and more. I seven shots in bull’s eye one inch in diameter at distance of twenty-five feet with the pistol, The accuracy of assed by any regardicss of price.’® C. S. Hoffman, 157 Oakwood Avenue, Orange, N. J KIRTLAND BROTHERS & CO., INC. 96 Chambers St. ( Dept P-S.) New York great American and you. Any Instrument or are interested in—Piano, Harm Music, Violin, Cornet, Mandolin oice , Voice urses, Send NO 6327 Siegel-Myers Bldg. \ »-UNDER MASTER TEACHERS Ma Ne alles A Complete Conservatory Course B M $s} Wonderful home study music lessons under pean teachers. Endorsed by Paderewski. Master teachers guide and coach ons a marvel of simplicity and completeness. Write telling us course you 1 Public School and ee oe en ee — we will send our coverin ail instrumentalan voc We ° UNIVERSITY EXTENSION CONSERVATORY Chicago, Illinois. If IN’T . J a id anracnie pend at ceed zeae precede, Ni trial.’ We will send it prepaid right to your home. | sae RTE nites von get ant ot your >send it back. f ‘ Soenae us $2.60 cimonth until $15 1% bas been paid. § (adies’ or men’s), Be sure Cx Can Tell Lachnite From | | a Diamond. Send Jt Back | : °Send me free hen it ririends can tell 1 decide to buy it H Write Today Serf rayarmrncrtavstsuscts 6 Haroia Lachman Co.,12N Michigan Av.Dept 8120 Chicago engines for less and give you the benefit Sizes 14 to 22 H-P. ¢ EASIEST TO _OPERAT! iy Use ch it fue / FREE s3': @B day for & special money ~- (x eae saving offer and Le ENGINE PRICES «in the face of rising eosts, I have reduced engine prices. By in- creasing production, making my factory the largest, selling direct to user, I build H 10-YEAR 90 Days Trial .Jonsak. 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July, 1920 coils until the antenna ammeter reads only about ten divisions. If the second- BE FRE ary is really in tune any slight change at Ou { @all in its number of turns will make a large reduction in the antenna current. *: Sn eniee te tatenines our wenkertal To use your wave meter. Fig. 1 om YOU-T H QUARANTEED S000 wiles ss | Shows a plan of the top of a meter. 0 0 ave ture-proof WEXCS ‘Tube win | First find what wave length you are ; each purchase of a tire. By Refer Mepimemat, |, SoG cu Muscles Like These? at once; offer ‘ Prices Include Tire and Tube AXIS It would mean tre- CONDENSER-C | | mendous strength, put- Size Tires Size —Tires THERMO AMMETER| | | ting you in a class above ERT | Ky} Soz3----* $38 bo y+ your felows.. It would ws. S188 13-28 t M, mean that you could on =" 19:68 14.50 outdo them in feats of 11.00 14.90 Free Reliner with Each Tire 4 | | strength and be a @ In ordering, be sure to state size wanted, also whether leader of men. It é 8. 8. clincher, plain or non-skid. Send $3.00 deposit on FIG.1 would mean a each tire, ce C. O. D., subject to examination; ; 7 : § per cent discount if you send full amount with order. Schematic view of wave meter. | | strong person- WEXCO TIRE COMPANY oo ality because 2626 Washington Bivd., Chicago a of your com- ————————EEE transmitting. The setting of the con- manding ap- if AM fe) 4) denser when the thermal ammeter Se hace ’ shows a maximum current gives this. | | ‘ET€?S ne 80 Oey Cemeerestam | Of course the exploring coil must not isc das : be moved while the condenser is being | | SUCCESS, 12 If You Love Diamonds adjusted. Sometimes radio experi- = —— | — ed at nh the Sean ohne menters have difficulty in telling just SOCIN as ed Ce buy. Get the ROYAL CATOLOG }OW what setting of the condenser cor- world. It and post yourself. It’sa liberaled i i 1 : and post yourself."It'sa liberal education in Sallie. ti: the: emnlemen. of: the would mean added lung power, un and Jewelry; tells how fo buy at ammeter for they have trouble watch- limited es and foyer oree you like, paying Monthly or Weekly. 2 pam ing both ammeter and condenser. They | | MOV!" all fears of indigestion Liberty Bondsaccepted. Write for "IF . . and disorders which undermine the Sccnteer ae een ee complain that the pointer G moves | | ‘ . once and ask for Edition 165, too slowly near its maximum deflection | | @V€T@8° man and make him old long ROYAL Diawonp X Watcu Oo to tell just where this motion stops. before his time. Mainen Lane New ween. If the power of the transmitter is ° 55 oo steady the operator may make several All These Things Ar e Yours trials and take the average position of I absolutely guarantee to do all this and more for you. ‘I have found the short cut to physical perfection and applied it on my own body, proving its resuits. I have per- | | sonally trained many of the world’s strong- | | est men by this same method. Why waste your time and money with old-time worth- less methods? If you are corns ye cane d BROAD a real robust man, follow the path of those 55 Fates EE Pir lhe ey rey one who have already made a success. Come s Wilson Common-Sense Ear Drums — [sate 2 now, get busy, for every day counts, Little Wireless Phones *? requi 8 f oe Se bellinn or Send for My New Book, medicine but effectively a & what is lacking or ‘‘Muscular Development’’ THERMO AMMETE POINTER-G ness or defective —e rom Thickened Drums, Roaring and |... -ge==——ge |S Hissing Sounds, Perforated, | JUN\NC-+--- a —eA defective in thenatural eardrums, They are simple Ceetenn, Se ee wearer easily fits into the ears where they are invisible. Soft, safe and comfortable. Write today for our 168 page FREE book on DEAF: » giving you full particulars and testimonials. WILSON EAR DRUM CO., Inc ted 885 Inter-Southern Bldg. ‘Louis KY. It tells the secret. Handsomely illustrated with 25 full-page photographs of myself and some of the world’s best athletes whom I have trained. Also contains full particulars of my splendid offer to you. The valuable book and special offer will be sent on receipt of only 1oc, stamps or coin, to cover cost of wrapping and mailing. Don’t miss this opportunity. Sit right down now and fill in the coupon. The sooner CONDENSER HANDLE \ you get started on the road to health the easier it will be to reach perfect manhood. Mind a File — Not a Pile Don't drag along one day longer—mail the The Key to Success is the ability to remem- coupon to-day. ber. Ican make Fay ky! C ae classi- “ select thoughts, fools, figures, names, FIG.2 EARLE ) oa LIEDERMAN faces. Enables you to concentrate, , p self-control, overcome : : Dept. 1207 203 Broadway New York bashfulness. forgetfulness, ad- Diagram to show how a tuning Ft A Le OE curve depends on condenser SS A SS SS SS SS LS SS SS ‘AY Remember” and hot-wire ammeter readings EARLE E. LIEDERMAN, my $9.00 book,” How to Speak in Public.” ‘ j Dept. 1207, 203 Broadway, New York City DICKSON MEMORY SCHOOL the condenser pointer. You can avoid r ; OS Coleage Av. Evanston, Hi, this, however, and kill two birds with Dear Sir:—I enclose herewith 10c for which you are to send me, without ary one stone, for you can get both reso- obligation on my part whatever, a copy cf eee ee nance and coupling test in half the time, your latest book, “‘Muscular Development.’ V4) ag?) as follows. When G shows almost | (Please write or print plainly.) the largest reading move C slowly LS YT) 5 A ee a ft” Wonderful, new device, guides your] pack and forth over several scale Dione nsiasdeccannssadés Lia eee hand; corrects your writing in few! divisions. If, meanwhile, G reaches | a q4ress ays. Big improvement in thr } : ee ene ee a eae | ee Terre reer or failures. ‘Complete outline FREE. Write| its maximum and retreats you are | 3 C. J. Ozment, Dept. 52, St. Louis, Mo. ready. Watch the positions of C when | City....................-0+5 Seatbesgs. ic sects 133 7 Annh

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ae : = - Faceragee) Ciguatarsneroadenies anaes hance oaetbace eran Seneca ~ Bea Certified Traffic Manager Learn By This New Quick Method Salary $2,500 to $10,000 A Year and More Get into this new big pay field now! The traffic director of a Detroit concern earns $19,500 a year—a Cleveland traffic man receives $24,000. Of course every man cannot equal these brilliant successes but numberless traffic positions pay from $2,500 to $10,000 a year. The work is fascinating and intensely interesting and the rewards are big. _Thousands of men are needed now. Why don't you qualify for one of these big pay jobs? Learn in Spare Time You can quickly master the secrets of traffic manage- ment through our simple method of spare time study. The American Commerce Association staff of experts can qualify you for a good traffic job in an amazingly short time. Vo u don’t need to take a moment's time from your present work—and after you have qualified we assist you to Secure a well-paid position. Write for Free Illustrated Book Let us send you this free illustrated book on traffic management and traffic opportunities. Find out -what we have done for hundreds of successful members and what they say of the A. C. A. Learn how we can help you to a lasting success and a position of prestige and im- portance. Don’t delay! Send us a postal to-day! Address AMERICAN COMMERCE ASSOCIATION Dept 147. 4043 Drexel Blvd.; Chicago. II. Let the mystic Ouija Board T Ikin B d reveal to you past secrets—or stretch forward into the un- a ing oar known future! On this Special Offer one _ -00 bill will bring you the complete Ouija oard with full directions for use. $4 Special Low Price Offer You can make the Ouija Board perform. Make it solve your biggest problems—answer vital questions—disclose secrets you long to know. It will startle you too with the truth of its pees Send only $1 with this coupon. The com-,e""" """"""" plete = ag pas will be sent at once o Binclosed dina e postpa' coupon today, NOW 6 $1.00 for which * send me the complete — Talking Beard of Ouija Board with direc- ompany Pa tions for use, postpaid. Dept. 2 36 S. Paca x Street, Baltimore, ,«* Md. ” BY DOING Every phase of all branches of ELECTRICITY taught by Actual Practice In America’s foremost and oldest institution for trade training. No Books Used Individual Instruction. Start Any Day a Write for FREE 64-page catalog THE NEW YORK ELECTRICAL SCHOOL 40 West 17th St., New York City G passes the same point, first as the reading increases and then as it de- creases. If you can note these two positions of the pointer of C you can regulate your transmitter. Take the average of these to find the proper setting for resonance. It is best that the amount of “retreat’”’ of the pointer of G from its largest reading be about two scale divisions before the condenser readings are taken. For instance, suppose you observe that 30 seems the largest reading on G. (You can make it read exactly 30 by moving the exploring coil L.) Now move C each way from its setting until G reads 28. If you are a good observer you can use a retreat of only one scale division instead of two. Now increase the coupling of your transmitting set. Keep the maximum reading of the ammeter at 30 by vary- ing the coupling of the wave meter coil. Test each time as above for resonance and you will soon find that the motion of the condenser pointer has to be about twice as much to cause the same retreat of the ammeter pointer. You should stop increasing the coupling of your transmitting set when you have to move the condenser through more than twice as much as you did with loose coupling for the same retreat. You may now rest assured that your transmitter is get- ting at a single frequency, the most energy possible with the power ap- plied to your set. To show what happens I have drawn the scale of the ammeter G at one side of that for the condenser, as shown in Fig. 2. You can see the form of reso- nance curve and also that a resonance curve is really built up from two separate motions of a point. A reso- nance curve is just a plot of ammeter deflections against condenser pointer deflections as shown in the figure.— O. C. Roos. A New Form of Wireless Aerial NEW form of wireless aerial has been experimented with at Scheveningen. It is the invention of a Dutchman named Vlug. The wires for a length of from 100 to 150 metres are lightly buried in the ground. They are said to be highly sensitive, with the result that two wires are in- sufficient for direct communication with Bandoeng (Dutch East Indies). A. receiver placed between the two contains certain improvements of Mr. Vlug’s invention. Comparison has been made between this wiring and the large antennae at Scheveningen, by which it was proved ‘that signals were louder on being received through ordinary aerials, but that not a letter was distinguishable owing to the dis- durbances. These had not entirely disappeared when enploying the Vlug system but had gained greatly in dis- tinctness, so that not a letter was missed. 134 Popular Science Monthly yNceueyel Quality Tires REDUCE TIRE eleXw al @) abe CosT 65e Akron Quality Tires are made to meet the increasing, demand for. recon- structed tires which are indispensab! to the ve pone eed of the auto indus eir economy is your eonal advantage To ingore roper! RS EES Shipped direct from factory to you, One tube given with each tire 30x3 ........$ 7.50 34x4._.....$11.85 30x34 - 8.60 34x44 13.55 32x3!4 oat 9.70 35x44 13.90 31x4....... 10.90 36x4%. 14.50 32x4....... 11.20 35x50. 15.45 33x4....... 11.50 37x5 16.50 Raliner | Free With Every Tire prow ed whether straight side or clincher Send $2 deposit for each tire ordered, balance C. O. D. subject to examination. If yousend fullamount withore >r, deduct 6 per cent discount. AKRON RUBBER CO. Robey and Roosevelt Dept. 20 CHICAGO, ILL. arvel of and i! 96.50 sat by wail ppd. Wo omy eabrean. 24N. Moteted St. W. Lake Street, CHICAGO SOME CLASS! OH, BOY! Just look at this speeder! Isn’t she adandy? Looks just @ an aeroplane; perfect streamline. You can build one exactly like it out of your car; especially FORDS. It’s easy. nd only $2.00 for our most complete set’ of blue- prints, photographs, and writ- ten instructions. “The ROADOPLANE” Box 154 BINGHAM, UTAH New Big No. 14-200 pp. Wireless and 100 pp. Electrical Catalog Wireless catalog mailed for 12c and electrical catalog for 6c. You may deduct this amount on first $1.00 purchase. Catalog not sent other- wise. Any wireless amateur will tell you it is the one catalog to have. As an encyclopedia _ of information it is invaluable. The largest and most elaborate radio catalog pub- lished. Values that cannot be duplicated elsewhere. THE WILLIAM B, DUCK COMPANY 212-214 Superior St. TOLEDO, OHIO CATALOG NO.14 The William B. Duck Co. DOARNES &, i SUBBERLEY {Derenee Arr wenney NATASHING TON 0.c. WILLIAM C. LINTON Consulting Engineer and Patent Attorney “Inventor’s Adviser’? Mailed free on request. Gives full information as to Patents, oa” Marks and Their Cost FFICE 364 UNIVERSITY sr. 916 Montreal, Canada. F ST. N. W., Washington, D. C. 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Telephoning to a Moving Railway Train HE question of devising a suitable method by which a telephone conversation may be held with a dis- tant, moving railroad train has lately been revived by the announcement that the War eeaeniabiai has ap- Cysts wl st legen tpi: =>. Fe ss em free ety ~ CANADIAN GOVERNMENT RAILWAYS , : Le h [SAFETY TELEGRAM --”-[rinst] | oe REE, L 62s.

‘ ESE the CR tom, = =— RL SG st 65074 . T@2 F728 by - ota | 3 " Td neta lee (for 25/1 r) &.. Copy of the first message sent to a moving train by the telephone system described parently succeeded in so doing. The wee ra plan, however,—known ‘‘wired wireless,’’-—involves a rather acess system which is also expen- sive. It is obvious that the telephone apparatus in connection with trains must be simple, rugged, and workable under all sorts of adverse weather conditions. One system has been tried out with interesting results, as evidenced by the photographs. If a distant train dispatcher rings, his bell circuit includes Coil A of an induction coil placed convenient to the rails upon which the train is moving. This excites a secondary current in Coil B. This current, of relatively high power, passes through the length of the track and hence to an overhead wire leading back to the Coil B. As this current passes under the car wheels a peculiar phenomenon occurs; for a small proportion of that current, not satisfied with easy sailing along that track, jumps up through the first car wheel, through Coil E in the car, and then back to the rail through the second wheel. This Coil E is as- sociated within the same induction

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TO DISTANT TRAIN CIRCUIT RETURN WIRE STATION < TRAIN TRANSMITTER <<

COIL D

Diagram of connections for send- ing telephone messages over wire and rails to moving trains coil with two other coils, C and D. J The current set up in Coil E produces still another one in C, and this one is in circuit with the train telephone bell when the receiver is on its hook. The Dispatcher’s ring, therefore, rings the bell in the moving train. When the train conductor takes the telephone receiver off its hook the bell 135

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a French inventor, M. Hurn. Sim lified Shorthand ) Ten different silver wires offer ten \BOBERT BROTHERS COMPANY Te wee Sox S-77 z TROY, OHIO of contact with Pel Tote. WE peesrinitasars wat & the crystal. With Learn method in five evenings home study; then acquire speed with K. I. Shorthand. Amazin ly simple, easy. Approved by ex- perts. Write dictation, messages, etc., as rapidly as spoken, after brief, pleasant prac- m tice. Nume ous special advantages to you, any one of these, Used in Army, Navy, Courts. Slight cost. For busy people, including you. Proot connection may eini lessons and brochure free. Address KING INSTITUTE, E B-188, Station _F, New York. be made by a = rotary switch.

in t Be a Jazz Mesic Master ¢s,, Yom cam. even if you Ruve ever touched a piano. ‘oat 4

7M . The crystal is so AVIAT ION F R E FE 2» Tse, Bum a tone, Cur method iol wi : will turn and for regarding the Aviation and Airplane business. 'Flad 4 if ane. 3 D jase —anitr 2) lessons, which you Dial with ten wires each one of the cutabout the many great o airplane aS ra cit musher in & lithe while— for different con- P w we prepare “ct will *nabie Fou to transform tacts with crystal contact wires qualify. yeraew ook “0 fae) wie tame whieh is running y : industry’’ also sent free it'ya you Jor at once. ust your head into ac thereare possible AMERICAN SCHOOL OF AVIATION = BEA - tay musi¢ on the rborn St. HI All by ear. twelve fresh points on the crystal sur- | —‘Ph186¢B_43'5. Dea

is Easy to Learn 9 FREE —Send at once for ee ing ae of Ja and face. There results a total of 120 FREE prospectus. Get posted ee ie Bea Sone Master § | POSSible points. The operator has now for the coming Spring, SS a eee je ‘vntorenne Sy te f | merely to keep turning and he will Summer, Fall. I pay goo aie = nee 5 Soe surely find a contact of the desired prices for hundreds of kinds of gy Fg ey Fo esitivit butterflies, insects, for collections. Simple ral —not at all— se ae : work with my pictures, price list, instructions. pastend seetee ee The device is shown in two pictures. SINCLAIR, Dealer in Insects, Dept. 7, ents et meg 4 | In the first are seen the silver wires Ocean Park, California ») timody piuy by ear. i i Keep Young Thru Pandiculation vA —oamnon i which form, with a galena crystal, the ae. Ss ew popular song detector. They pass through the bit. ye. the une. gp! it ° ° ° r Just center of an ebonite disk, in groups of ay 2 A ability five on two small eccentric arcs. On a will make happy, the other side of the disk they meet wien von Skee the sewest aome oem Fou, will be the crystal. The latter may be turned You feel the need of exercise. You haven't time. 15 min-

tern Heuston itt 4 Gome by eur . F — use of nor gerne ——— 2 noure in gymnasium. i see Wome Waster" an f or xives you punch, Pp, and vigor. e lazy man’s m. few inate. "Tae Miners Method” Socay. fe te bramfal of about an axis passing through the | $)vs,2oU RPRiok® y man's gy MACGARs SC HOON OF MUSIC. Niagara Falls. N.Y, center of the disk and as it does so The Pandiculator Co., 343 Advance Bldg., Cleveland, O. —_— a a a sY_- o

— _ each wire follows along a separate . thont Bae nm ip ane. g come mad te address below, your . — The Sagres Meri Ft el circular path on = the crystal sur- face. The other pic- ture, that of the | assembled de- vice, shows at the top a small vertical cylinder Saws 25Cords aDay | which may slide Phe Ota Ott wa Log Sew y Sein Senso cn ovin ott stumps 8 up and ge grou cuts u * eutter, runs dp jack and otherbelt mackinery, Moutted pin on its side

TRIAL t this ad and mail it to us, with your name and Seon ny, no money); and we will send you our FAMOUS KARNAK RAZOR by return mail, postpaid. You may use the razor for 80 days FREE; then if you sia! it, pay as

$1.85. If you don’tlike it return it. SEND O MONEY. MORE COMPANY, Dept.397 St. Louis, Mo. GET BIG BUSH | OFFER Agentsonly. We do not deal

: on wheels ean 0 Year Guarantee, may engage with a Honey-Reck cuar- Deve seie. Write or Free eo el Cashor Easy Terms, This detector gives Ps = SS. Oniy - antee. Bush light OTTAWA MFG.CO., 1801 Wood St., Ottawa,Kans. | any of twelve —— 120 different adjust- GUSH MOTOR CO., Chicago, tllinois, Dept.cit? Bush Temple | vertical slots ments of the silver . E IS MISERY peg eo gear mel and thus hold crystal contact - ——" I-was Deaf and had Head Nolses organ, flat, hoops, it fast To S for over 30 years. My invisible feet Ear bale - ties, tacks, ‘ m SN = Drums restored my hearing and sto) ~~ Head sone, 2 nails, barbed-wite, | Operate, one rotates the switch, test- 4 and will doit for you. ‘They are Tiny Megaphon concrete re-inforce. Cannot be seen when worn. Effective when dees i j s caused by Catarrh or b Perforated, Partially or ting; wire a posts, oe bee ae. ing the ten points thus allowed, and Winily Destroyed Natural ana ane to gut i in, bonds, wire w auto-towing cables, horse-shoes, then turns the crystal container to the a gt a hy el illustrated Books Describing Uses, FREE | next slot and repeats with ten fresh gtatement of how I recovered my hearing. American Stee! &WireCo.”™"s,758°"" | points,

A. O, LEONARD Guite 301,90 6. Avenue e« e WNew York City 136

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July, 1920 A New Mounting for Bank- Wound Coils SIMPLE mounting of the type needed for use with banked coils or those of the “‘honeycomb”’ style is shown in the illustration. A D.P.D.T, Using porcelain switch base to mount and to couple bank wound coils switch, such as can be bought for about half a dollar, and a little work is all that is needed. The contacts of the switch are re- moved and bolted in the holes that were formerly employed to take care of the lead wires. This is necessary to permit plugging in the standard makes of coils, the contacts of which are rather close together. The switch blades are removed. In their places are inserted a male and female plug. One of these is made from a 3/16-in. wire terminal. It is soldered to a long bolt and put in the place of one blade. The other is a piece of heavy copper wire with the end flattened, drilled, and bolted in place of the other switch blade. Coils plugged in the end contacts are moved by hand. The center coil, which fits into the parts just described, can be moved by a knob, as shown. Mounting Radio Instruments on a Panel HE most recent method of -mount- ing instruments, especially those used in the receiving set, is in the form of a panel, the various units being in- serted in round or square holes cut expressly for this purpose. The instruments used may be mounted on disks of fiber or bakelite, Bristol board panelonwhichis mounted phonograph disk carrying apparatus or on old phonograph records, which may be bought cheaply at second Give the world the once over straight talk. Many a man when he gets to be 40, misses some- thing. He may have lots of money, and a fine family but— He never “got out and saw things’. After he gets settled down, it’s too late. Every man wants to see the world. No man likes to stand still all his life. The best time to TRAVEL is when you’re young and lively—right NOW |! Right NOW your Uncle Sam is calling, ‘“‘Shove off!’’ He wants men for his Navy. He’s inviting you! It’s the biggest chance you'll ever get to give the world the once over! | ye fellows, to some Shove off !-Join the U.S.Navy The Navy goes all over the world—sails the Seven Seas— squints at the six continents— that’s its business. You stand to see more odd sights, wonder- ful scenery and strange people than you ever dreamed of. You’ll work hard while you work? You’ll play hard while you play. You'll earn and learn. You’ll get, in addition to ‘‘shore- leave”, a 30-day straight vaca- tion—which is more than the average bank president can count on. You can join for two years. When you get through you'll be physically and mentaily “tuned up” for the rest of your life. You’ll be ready through and through for SUCCESS. There’s a Recruiting Station right near you. If you don’t know where it is, your Post- master will be glad to tell you. Soaweyourtfeet From That Tired, Aching, Broken- Down Feeling. Jung’s Arch Brace, just out, is an elastic, light, comfortable, economical and corrective brace. Relieves tired and aching feet instantly. Corrects fallen arches and foot-strain. Strength- , No ungainly humps. Made of F Recommended “o.\ by physicians. Guaranteed. Pric® $1.00 per pair. my \s | Money back if not satisfied, Order today. e 65% Booklet free. Ask your shoe deafer or druggist. taught thoroughly. TELEGRAPHY Morse and Wireless ‘atalog free. Big Salaries. Tremendous Demand. All expenses low; chance to earn part. Largest School in America; established 45 years. Dodge’s Institute, 9th St., Valparaiso, Ind. With Each Razor NIK Ua You Take No Risk WriTTEN GUARANTEE hand. T f instruments ma This Shumate “Barber” razor is so good that we dare guarantee it to you “ag Id i gh yo fina b oes = for life. Here’s the reason—the blade is made from Tungsten Alloy Steel, which takes a keener a . va ‘ite = edge than any ordinary steel can—and it holds it. You can use it for years without honing. The small switches or other similar ee secret of this wonderful steel is ours alone, and we guard it jealously, Sanat that thes ceuciep-cied bind. |. Wench Rimmmeaie tases aeetealiieh dee ack alpina such a wa a ey overiap an in = as you like, If you say alter an exacting tri you don ° on the vl of the "aes sagcduiaan = To settle peer vg question for life, — us $2.00 and the SHUMATE Barber ’ is P = Razor wi t to you post pai The author's receiving set is shown = $2 * For those with v wage iry beards, we recommend our $3.00 SHUMATE herewith. This set costs less than $25 Razor, soiadaite oaeialh Yor this purpose, In remitting, give us your dealers complete, including three homemade vacuum valves.—R. U. CLARK, 3rd. = Established 1884 name, and a chamois lined, rust-proof case will be included with your razor. SHUMATE RAZOR CO. 851 Chestnut St., ST. LOUIS, U.S. A. SPSL EUUUELRLULU ULLAL, Capacéey 10,000 Razors Daaily |i iiiiiiiiiiiiiytiiiniiitiiiiiiiiitl 137 TNNIUULIL TONUINIHAN FTAA

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|__| Starting - point \} and Goal Bik The records of Veeder | Counters pzovide both the starting-point and goal for increased production from your machines. By showing up the routine rate- Wit of-work, these records give you Hill a definite figure from which to go on and improve. ||) The records further indicate an inl attainable capacity or standard Hit for a machine—and this is the it goal which

SAS SN OE I ST - pores

COUNTERS | Hi help you reach by counting iH production as the machine works ii and checking-up the industri- ousness of the operator. The small Revolution Counter below it registers one for a revolution of a shaft, recording a machine-operation. ; Though small, this counter is very t : durable; its mechanism will stand a very high rate of speed, making it especially suitable for light, fast-run- ning machines, and most adaptable to experimental work. If run backward, the counter sub- tracts. Price $2.00 (Cut nearly full Hi size.) The Set-Back Rotary Ratchet Coun- ter below is for larger machines, i such as punch presses and metal-stamping Ra machines, where a reciprocating movement { i 4

indicates an operation.

Registers one for each throw of the lever, and Lb sets back to zero from any figure by turning Tt knob once round. Supplied with from four ay to ten figure-wheels, as required. Price with Fel four figures, as illustrated, $10.50 (subject to 7. discount). Cut less than 1% size. There’s a Veeder for every purpose where you could pos- | sibly use a counter. Write for the new counter booklet. q if The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn.

An Air-Pressure Ram for Garage Use HERE are numerous cases in garage work where a series of blows, or prolonged pressure, is de- sired to drive in or out certain parts that cannot be reached with a hammer or bar. To supply such blows or pressure the following ram, working from the air system in the shop, has been devised. It is capable of a blow depending upon the maximum pres- sure in the supply tank and will be found convenient to use in places not readily accessible to ordinary tools. The base consists of a large pipe flange, bolted to a supplementary base of heavy sheet iron. This larger base SOLID STEEL 4

PIPE

AIR-HOLES . MOTORCYCLE PISTON SWAY SHUT~OFF PIPE=CAP ™ RIVETS y SSAA ty SSS ie— AIRP PRESSURE PIPE

FLANGE YL, | 4: a

SSS aaamemebit )__ EXTRA BASE

Made from old engine parts, this air-pressure ram will do excellent work in the garage is to give the ram stability when work- ing under a movable part of a chasis or in other work of a like nature. Thread a large pipe cap about half way down on the outside so it will fit inside the flange opening, closed end down. This acts as a retaining wall for the air chamber. Then the cylinder to the ram, consisting of 1 ft. of pipe, is threaded into the inside of the cap. Make up all joints tightly as possible, and with lead filling. The sectional illustration shows the manner of as- sembling. No dimensions of the vari- ous parts are given as they depend upon the diameter of the ram itself. The ram consists of two parts, the pressure end and the hammer. The first is made from a small gas engine piston, about the size used in a four cylinder motorcycle engine. Procure one that will accommodate itself to the inside bore of some standard size of high pressure pipe; about 11% in. in diameter. This diameter, however, may be varied. Be sure the rings are in good condition and gas tight. Then turn out a piece of solid steel similar to that shown in detail. The neck should make a snug fit inside the open end of the piston, and fasten to it by drilling and tapping several holes about its circumference and using countersunk screws. This places the piston head down when the ram is inserted in the cylinder. The cylinder should, of course, be bored out and smoothed on a lathe before making it up with the rest of the pipe fittings. Where the cylinder enters the cap, 138

Popular Science Monthly

Tapes Steel Scales as: Boxwood and Spring Jt. Rules ACCURATE. Ask your dealer. = Ask us for Catalog No: 12 THE [UFKIN PRULE (£0, 54384. Get a Copy of Our Complete Wireless Catalog and Order All of Your RADIO MATERIAL eae From One Source of Supply and Save Trouble Send 25c for a copy of Wireless Manual and Catalog A 12 You cannot get satisfaction from wireless instruments unless they are absolutely perfect. The slightest imper- fection in construction destroys their efficiency. We offer for sale wireless apparatus only of the highest quality, guaranteed to be mechanically and electrically perfect. Our combined Manual and Catalog illustrates and accurately describes the uses of standard radio instru- ments and should be of great assistance, not only to the amateur but to the professional user and experimenter in selecting proper radio material WE MAKE A CHARGE OF 25C FOR THIS MANUAL, ISSUING A COUPON REDEEMABLE ON AN ORDER FOR $5.00 OR MORE. IT 1S THE LAST WORD IN WIRELESS CATALOGS. SEND FOR A COPY NOW. YOU CANNOT AFFORD TO BE WITHOUT ONE WHEN YOU WANT TO BUY. Manhattan Electrical Supply Company, Inc. New York, 17 Park Place St. Louis, 1106 Pine St. |_Chicago, 114 So. Wells St. San Francisco, 604 Mission Se.

ouie Power Benders

) inches. Send for printed mat- ter. We also manufacture TEN other sizes, hand operated to bend from 1-8 to 6 inches.

Send for this Free 118 Page Book. It tells how you can gain a thor- ough knowledge of law in your . Splendid op-

spare time. as 40,000 others are doing portunities in the profession of law. Busi- ness today needs law trained men. Free book gives experiences of succegsful law trained men, and tells how you can read flaw under guidance of Ex- President Taft and 80 other ly eminent authorities. j “SNNED | Blackstone Institute | MA pt. 120B 608 S. De rn Street, Chicago Bit for Machinists and Toolmakers Write for bookl th best built and most ut seonins ie tion of Tool Cases on the market. We ship direct from factory and guarantee to please you or refund all money. Merslaer iSeny &0 Columbia St., Dayton. Ohio

Golden Gem u $ py PORTABLE. For Bermmendation > |Adding Machine rsonal De: It zg TA ay | General Office” IC GGegg ag [\ It checks mental calculations} Buy through your stationer. |i) Write for 1-day Trial Offer} P.E. Gancher, A. A. M.Co, |@/, 148 Duane St., New York |g Canadian Agency | far Mit 104 man 205 man 19.07 us 48D Kot . \ Multiplie : q SAVE 25% TO 60% on slightly used GRAFLEX-KODAKS Ne me 1 <6 4 Cameras and Lenses of every description. Yih y Gs Equal to new. Save money. Write now for IMICY Free Bargain Book and Catalog a listing hundreds of money-saving bargains in slight- re 2 " ly used and new cameras pplie: ack if not satisfied. ou. take dealing with us. We have been in the photo- graphic business over 16 years. Write now: CENTRAL CAMERA CO., Dept. 67, 124 S. Wabash Ave., Chicago Over 100,00 Noctis td nen use

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- tract and Illustrated Catalog Free. STANDARD FOOD AND FUR ASS’N 407C Broadway New York Panylar Nerence Monthly

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July, 1920 drill and tap a hole for the air intake pipe. Seat a three way shut-off in this opening and connect it with the air supply. The end of the shut-off should project a little into the cylinder to act as a rest for the piston when at the end of its down stroke. Just above the top of the piston, drill several small holes about the circumference of the cylinder, to serve as air outlets when the piston rises and reaches that point. To operate the ram, place it under the part to be driven, turn on the shut-off and admit air to the cylinder. This pushes up the piston, with a sharp blow. By turning the shut-off one way the air is released and the piston drops. This operation is repeated as often as necessary. If the piston reaches too high a point the air pres- sure escapes through the outlets in the sides of cylinder. The ram is oiled by dropping oil between the ram and cylinder walls at the top. A Bench Light Bracket Made from Automobile Parts HE steering rod of a Ford, or other light car, and a pie tin may be combined to make an adjustable elec- tric light bracket and reflector for the work bench. The steering rod should be the one fitted with ball socket joints at each end and the ball pins which fit them should a'so be used. The arrangement is fully illustrated. BALL= The foreman says “I suppose it’s because I used them myself when I was at the bench, but it does seem as though the best men in the shop have a prefer- ence for Starrett Tools. “‘Of course, most of them sort of got into the habit of relying on Star- rett for fine work when they were apprentices and journeymen. ‘‘Speaking of apprentices — that little red book there, ‘The Starrett Book for Machinists’ Apprentices,’ has saved me more time and helped more young fellows to learn how to do things right than anything else in the shop. ‘*When a young lad asks me how to do this or that, I usually tell him or show him, and then ask him if he has one of those books. I’ve noticed that as soon as he gets one of them he doesn’t have half so many questions to ask. ‘Starrett gets out another book, ‘The Machinists’ Data Book,’ that’s just about as big a help to the experienced machinist. It’s got all the tables and formulas and so on that he ever needs, and it isn’t cluttered up with a lot of engineers’ stuff that he doesn’t use. **Yes, I bought one of each of the books down at the hardware store, as soon as they came out. They cost me seventy-five cents each, but they’re worth it.” The L. S. STARRETT COMPANY THE WORLD’S GREATEST TOOLMAKERS Manufacturers of Hack Saws Unexcelled JOINT tie - ATHOL, MASS. Machinists the world over have put Ges. their faith in the accuracy of Starrett Tools for thirty-nine years. Write for ‘ |: illustrated Catalog No. 21 ““W"’ 42-40 BALL=JOINT. $10.00 FOR YOU. ARMATURE AND MAGNET WINDING How would you like to make $10.00 a week during your By Horstman & Tousley BALL PIN qpere time? Others ore Sine © Or representing POPULAR he hooks fet electricians. Fu Wl facts and dia- IENCE . $1. a yoni Popular Science Monthly __22 West 39th Street, New York POPULAR ENCE MONTHLY, 225 W. 29th St, New York WY \\GHT SOCKET SOLDERED THROUGH HOLE eek Battery Charging Outfits To operate on A. C., 60 cycle, single phase.. Voltage as specified. To Buy New Guaranteed Electrical Your Opportunity pd Pan 110-220 volts, A. C., le ~ volts, 60 cyc Suitable for all lighting, nales 2 and 3 phase, A. C., 220 v. 1800 R. P. M. with pulley Charging and Power 60c., eR PM. complete Wg teiahatter=: $28-50) we $i9solnnr ea “ 19.50 ¥% Aaa “ fp RE ere $38.50 ~aaaanee — sain po IAS. wt, SERED To He Nettie Se 50 | avis - $31.50) ° | W908 w, {eemgetee goesolmemee - $31.50|2 EF - $81.00] “Huateitcr. $6850 se, with alding eve = S&P. - $96.00) "i Ae Thre, $68-50 110 wi,tem. - $46.50 2 1.0. 10-20 ws .50 repalaion, sliding $116 Smp.. $112.00 19.8 2. 2 wat, $88.50 aa $142.50 paenee oo SRM $194.50 | urnetunrke Stoe ey | Hese? $3G-50 | Masi Mm $7.00 WRITE FOR CATALOG. BARGAINS IM MOTORS AND GENERATORS Cee an x. $106.50 1 /qiv. WASHING MACHINE MOTORS ; a | AIPPING TEX TERMS: 2 tigen si There are always old automobile parts around a garage. This article tells you how to make a bench light from them _ Bolt one ball pin through a board placed vertically over the bench. Draw up a nut each side so the pin will not turn. To the ball is then attached one end of the steering rod, the socket being tightened over the ball until it can be moved only by considerable pressure. Bend a second ball pin so it is turned at right angles as shown, about half _ way down its ength. The ball is then tightened up in the bottom socket of the steering rod. The open- ing faces out. Then the pin is bolted through the side of a pie tin which is used as a reflector. This holds the tin at an angle when the rod hangs straight down. The light socket is 3 H. P., 110-228 volts, repulsion, sliding base on all orders. Ran ® ©. 6. with Bill of Ladiag attached by freight. MANUFACTURERS’ DISTRIBUTER CHAS. H. JOHNSTON, Box 14, West End, Pittsburgh, Pa. rT FF. tnnn

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Lo a EL Eg A SO RO A soldered through a hole in the center of the tin. If the ball and socket joints work too easily, remove ‘one half of the socket and grind down the flat sur- face until the halves fit so close to the ball when the nuts are drawn up that some pressure is necessary to turn it. This will enable the rod to hold any position into which it is swung. Do the same with each one and place a little grease in the joints. Wire from the light can be run up the rod to the rosette overhead.—T. HALLETT. Re-Cutting Worn Files to Renew Them N these days of efficiency and high prices, every effort is made by managers of machine shops, .auto- motive plants and other factories to keep operating costs as low as pos- sible. The utilization of articles that were formerly regarded as waste, once they were used, is receiving the atten- tion of various manufacturers who are saving large amounts of money yearly by reclaiming used lubricating oils, dirty waste thrown away by workmen and other articles. The railroads are leaders in this respect, having worked out the problem with the greatest efficiency. The writer has found during his travels over the United States and Canada, that in the average machine shop, using quantities of files in a year’s time, the foreman does not always know that worn files can be re- cut and so, allows them to be thrown in the scrap heap. In spite of the * |e == Me Sel Aj BS p Prett) In these high cost of everything days the need to re-use old tools is great. Files can be made new this way extensive use of machinery, there is some work which has to be done with a file, since there is no substitute for it in certain lines of work. Files as cutting tools are used so extensively Popular Science Monthly or Saw Rig ¢When You WantIt Save you $15 to $500--Cash or Terms--Imme- . diate Shipment—2, 3, 4,6,8,12, 16,22 or 30 H-P —Stationary, Portable or Saw-Ri. £ Fetal gution Bugis te bent titer fet Eas tart--winter or summer. kerosene, y tos WITTE ENGIN 4 ' With BOSCH Magneto Log Saw--the Sovst practical for ave Dae easy to operate--ready to use. Book FREE. Wirre ENGINE Works patie ene KANSAS CITY, MISSOURS ( Scissors and Tweezers MATHIAS KLEIN & SONS, Mfrs. Electricians’ Knife We can meet dealers’ demands at once and offer attractive quantity prices Write for description 5 CANAL STA. 3, CHICAGO 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. KEASBEY & MATTISON COMPANY ASBESTOS We are miners and shippers of Crude Asbestos For anything you want in Asbestos, turn to Dept. S-4. AMBLER, PENNA., U.S. A. Owners of the world’s largest Asbestos Mines that it will pay to recut them, and 140 Pilliod TOOL CASES EXCEL Machinists, Tool Makers and Carpenters find them most satisfactory in construction, appearance, service and price. Immediate shipment. Booklet describing 20 styles equest The Pilliod Lumber Co. Dept. A, Swanton, Ohie Popular Science Monthly

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9S Iv in S, Os EL and nost tion, rice. hie July, 1920 ee oe Red Devil Pin Punch Set REG.U.S. PAT. OFF. = A SMITH & HEMENWAY co a. © IAVINOION NJ EVERY TOUL GUAMANLEED A useful little kit for the motorist or mechanic. Six Pin Punches with fol- lowing point sizes :— 1/8” 7/32” 3/32” 1/4" 3/16” 9/32” Each tool has a 5 inch han- dle and a4 inch ground point. Made of what is absolutely the best material for the purpose:—Octagon stock Swedish analysis point 80 Carbon Steel. In a khaki case as illustrat- ed. Complete set $3.00 at your dealers or from us direct. Mention Style No. 483 Booklet of mechanics tools on request. Smith & Hemenway Co., Inc. 264 BROADWAY NEW YORK CITY this can be done by the man who sweeps out the shop. It takes only a few minutes of his time, if too many are not allowed to accumulate at one time. Two dozen can be conveniently handled by the shopman without the work interfering with his other duties. The acid mixture is cheap in price. In fact, many mills and factories have a supply of the acid on hand, as it is used to remove the scale from iron or steel. In the formula given, the pro- portions of sulphuric acid and water are so combined as to do the recut- ting in from 10 to 12 hours. All the shopman need do is clean the files and put them into the acid solution before leaving the shop at night. In the morning they will be ready to remove, and they will be found as clean and bright as new. To get the best results first clean the files with a ‘‘file-card.”” Then put them into a mixture of four ounces of washing soda and one quart of very hot water, scrubbing them with a brush. This removes any oil from them. Then rinse thoroughly so no soda solution will remain, and trans- fer them to the acid fluid. This is made of four ounces of sul- phuric acid and one quart of water. To mix it, pour the acid into the water slowly, stirring it with a piece of glass or a stick. Do not reverse this pro- ceeding, or the acid will fly up into your face. Too great care cannot be taken when handling acids. Mix the acid solution in an earthenware or glass vessel, making enough to cover the files. After the files have remained in the fluid 10 or 12 hours, rinse thor- oughly in water to remove all traces of the acid, then dry and oil them and put them away until they are wanted for use. In some localities, the water is al- kaline and more acid must be used to counteract this quality. Distilled water will obviate the necessity of adding more acid in using alkaline water. The re-cut files will do good work, and reduce the “‘overhead cost’”’ to some extent.—W. S. STANDIFORD. Cutting Thin Disks in the Lathe HE amateur sometimes experi- ences difficulty in trying to cut large, thin washers or disks in his lathe. The best way to do this is to attach a wooden chuck to the face plate. This does not need to be round as shown in the illustration, though such a shape facilitates facing it off. It should be faced off smooth and with a plane sure face, as shown by applying a straight edge. Then the sheet from which the disk is to be cut is squared up and holes are drilled in the corners for wood screws to attach it to the wooden chuck. The sheet, if kinked, should be carefully straightened, for it must fit evenly on the wood block. If there is any strain on it, the sheet will buckle when the cut is made and probably spoil the work. ‘141 Eternal Vigilance and Drop-Forgings Whether or not “Eternal vigilance is the price of liberty,” it is cer- tainly regarded as absolutely essen- tial in the manufacture of Williams’ Superior Drop-Forgings and Drop- Forged Tools. Each bar of metal is bought to a definite standard. Before the stock is released for use, it is rigidly checked by exhaustive Laboratory tests: all material failing to meet the exacting purchase requirements is rejected. As a further safeguard, each finished forging of regular stock lines, such as “Vulcan” Eye Bolts, ‘‘Vulcan” Hoist Hooks, etc., is proof-tested in a stand- ard tension machine to a predetermined proportion of its catalog strength. All parts passing such tests are perma- nently marked and none of these goods can leave the works without bearing this record of certified strength. Highly developed craftsmanship and modern methods, combined with searching, scientific tests have made Williams’ forgings Superior. J. H. WILLIAMS & CO. “‘The Drop-Forging People’’ 7 Richards St., Brooklyn, N. Y. 7 Vulcan St., Buffalo; N. Y. 7 So. Clinton St., Chicago, II. Williams’ - “Vulcan”’ Safety Lathe Dogs Bent and Straight Tail. 16 sizes—%4 to 6 inches— 1 or 2 Screws. ASK FOR BOOKLET ——_O= — Wee

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aga SIMONDS FILES For Every Mill or Shop Use— Why did a SIMONDS file win the gold medal at the Seattle Exposition in 1909 and again at the Panama- Pacific Exposition at San Francisco in 1915? Be- cause SIMONDS Files are made of absolutely uniform quality and the SIMONDS special cross-cut saw file will average at least 16 per cent more work than you can secure with an ordi- nary file. It pays to use SIMONDS Files. They are backed by the SIMONDS Guarantee and 88 years of universal satisfaction. Simonds Manufacturing Co. “The Saw Makers,’’ Established 1832 Fitchburg, Mass. Chicago Montreal New York Portland, Ore. Memphis San Francisco New Orleans Seattle SAW STEEL SI | Hasta The disk is cut out by means of a thin tool something like a cutting-off tool. The center opening is cut first, if a washer is to be made. It would be a good plan to screw a metal or hard- wood disk over the hole as shown, in order to help hold the sheet in shape ~, Pd (A ® s..---” © CIT’ Ugg ae VS L4 LUI VA To cut a large, thin washer, the plate is first screwed over the inner hole before cutting theouter circum ference while the outer cut is being made. Too much pressure must not be put upon the cutting tool, for there would be danger of the tool breaking through at one point and spoiling the piece.—H. H. PARKER. An Accurate and Quick Way to Gage Screws N a factory, not long ago, we had two fairly large sized boxes filled with a mixed lot of machine screws, varying in size from 6 in. by 32 in. to 5/16 in. by 18 in. To sort these and put them back in stock looked like a slow, tedious job. We saved considerable time by making a screw gage as follows: A piece of sheet steel 1 in. thick and 12 in. long by 6 in. wide was cut into six slots about 101% in. long. Each slot x= 2 0-24 —— - 26 —————— —— SECTION SHOWING GAGE IN USE Made from a piece of steel, this gage sepa- rates assorted screws by various sized slots was just wide enough to admit one size of the screws. There was one slot for the 6 wire screw, one slot for the 8 wire screw, etc., with no chance of getting the wrong screw in the wrong slot. The boy could take up a handful of screws and drop them into the slot where that particular size screw be- longed. When one slot was full, he could hold the other sizes back while he slid the slot that was full into a box. This method will save a lot of time.—H. BARNUM STILLMAN. 142 Popular Science Monthly The Right Way to Make Wire Cable TELEPHONE line was to be run from a rural community into town, and three men were assigned to the job of putting up the poles and placing the wire. At corners it was recommended to use twisted wire cables, but since there were no cables at local markets and not the time required for a shipment to arrive, it was necessary to make them by hand. At first the cables were made by securing six or eight wires to a post, and twisting a stick to which the other ends were tied. This resulted in a poorly twisted product. The wire was loose at the stationary end, but tight at the other end. In order to get a cable that was uniform from one end to the other an old iron wheel was bolted to the back of the supply wagon, as shown. The bolt was run through the two by four which formed the rear bed piece of the wagon box. When it was necessary to make a cable, the wagon was hauled to the side of the road, the brakes locked, and a stout stake set in the ground fifteen or twenty feet from the back end of the - WAGON WHEEL A {WIRES TWISTED INTO SABLE BY REVOLVING WHEEL WIRES FASTENED To 7 SPOKES OF WHEEL | eee A wagon wheel used as shown will make a tight and uniform wire cable wagon. Wires were then run from this stake to as many spokes of the wire wheel as there were strands desired, being placed first at the outer edge of the wheel. The stake was then re- volved a number of times. The ends of the wires on the spokes were then pushed 2 in. nearer the hub, and a few more turns of the wheel were given. This was kept up until the wires reached the hub and the cable was finished. With the wires far apart at first, the angle which the strands met was kept approximately constant, which is necessary to result in an even twist. The wagon gave enough under the strain to keep the wires tight, sliding back as the pressure increased. A little practice produced a good cable that was evenly twisted from one end to the other, and which required only a small amount of labor to make. The same principle has been applied where small lengths of such cable was wanted from time to time, as in fence- making. The wagon was blocked, one rear wheel jacked up, and wires were tied to its spokes. As the wheel re- volves it twists the five wires into a uni- form cable. The apparatus is easy to make and the few parts may be picked up at small cost. —DALB R. VAN HORN..