Popular Mechanics 1926-04: Vol 45 Iss 4

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It takes only ” for Ps Big PayJo} ! * Read what these men are doing in .. the Auto, Tractor and Electricg/ \ ' 3 Business. Here is your big chance cco. ws sar ll ro 4 to get ‘‘on easy street.’’ Come to rat a a My method is the shorvest the great McSweeny Shops on the 45 1 : T II 5 = m ¢ n — 4) —- _ ~ for training Big Salary n on. = 2 ss ive eee. biggest Special Offer ever made, George W. Smith runs a big Ford 1. Me 7 4 a Agency and Repair Shop at West a Firms ts p if inl Alexandria, Ohio. He says, “I am clearing over $800 per month.” . f The Auto, Tractor and Electrical Business is o1 boom. Thousands of trained men will be needed during th« months. I get calls every day from Garages, Battery St Auto Repair —~s and other successful concerns for Mesw men. When the big fellows need high where to come for them. McSweeny Trained Men Earn *75 to $150 Weekly . Scientific tool training—that’s the seeret. C. FE. Gillisp'e has charge of a ing to the latest engineering standards. -grade men, You do things he Thousands of do} fleet of trucks and tractors with the been spent in modern tools and equipment. That’s whv mv n State Highway Commission, due home in the biggest shops in the eountrv. If vou want to: to MeSweeny training : way Smith and Collins and the rest have—qualify by the sam _ PI Pay Your Railroad Fare and Board You In order to fill the openings that now exist, I am makin: no one has ever made before — Free railroad fare, Free beard. But even that is not all. Vil tell you about the rest in 1 ] W. W. Peace gets $250 a mont ai guises sectors tes Send for FREE Book My big illustrated training book tells how others are su It tells many things you ought to know about Autos and Write for it and my short time offer NOW. It soon Mc WEENY|: TRAINING SHOPS CINCINNATI CHICAGO Sth and Wainut 517 So. Laflin McSweeny futo, Tractor and Electrical Training Shops, Dept. 149 (Address shops nearest you) Cincinnati, O., or Chicago, Iil., D. M. Collins, Williamsville, West Virginia, writes, ‘Shortly after finishing McSweeny training, I started in as manager of a garage at $300 per month.”’ Without any obligation send me your big free bool Also information revard ng spec al temporary offer Name 3 | aa CA chonsneme

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Swe notch. Krrpinc your “B” batteries full of pep, without frequent renewals, is simply a matter of using the right size Evereadys for your particular set with a “C” battery*. The rule which determines the right size “B” batteries to use is simple, and once learned definitely settles the question of “‘B” battery service and economy. On 1 to 3 tubes—Use Eveready No. 772. On + or more tubes—Use the Heavy Duty “B” Batteries, either No. 770, or the even longer-lived Eveready Layerbilt No. 486. On all but single tube sets — Use a “C” battery. “Your radio 1s always top What do you do to keep it so full of pep?’’ POPULAR MECHANICS ADVERTISING SECTION 95 770’s or 2 Eveready Layerbilts No. 486—looks at first glance like an economy because of lower first cost. But in a few months the 772’s will be exhausted and have to be replaced. After the same length of time the Eveready No 770’s or the Eveready Layerbilts No. 486 will still be good for many more months of service. We have prepared for your individual use a new booklet, “Choosing and Using the Right Radio Batteries,” which we will be glad to send you upon request. This book- let also tells about the proper battery equip- ment for use with the new power tubes. When following these rules, No. 772, on 1 to 3 tube sets, will last for a year or more; and Heavy Duties, on sets of + or more tubes, for 8 months or longer. These life figures are based on the established tact that the average year- round use of a set is 2 hours a day. A pair of Eveready No. '72’s for a 5-tube set in- stead of 2 Eveready No. L AGO Laflin Lerr—No. 486, for 4,5 or more tubes Ricut—Ever- eady Dry Cell Radio“ A’”’ Bat- tery,1% colts. *Note: In addition to the in- creased life which an Eveready “C” Battery gives to your “B” batteries, it will add a quality of reception unobtainable without it. Manufactured and guaranteed by NATIONAL Carson Co., Inc. New York San Francisco Canadian National Carbon (o.. Limited, Toronto, Ontario $5.50 Tuesday night means Eveready Hour —9 P. M., Eastern Standard Time, through the following stations: WEAF-New Yor wsar- Providence WwEEt-Boston WTAG-—W orchester wri-Philadeiphta war Buffalo WCAE~—Pittsburgh Ksp-—St, Louts Wwsal-C .ncinnati WEAR- Cicvcland wws-Dertroit WGN-Chicago woc—Daprenport § Minn wcco ? St. Panui -they last longer “ + * Pacific Coast, Eveready Program KGO-San Francisco, 8 to 9 P. M

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A Sandy Hook Pilot Leaping from His Small Gig for the Jacob’s Ladder of a Giant Inbound Liner during Wild Wintry Gale, a Perilous Procedure—Sze Pag: 539

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Popular Mechanics REGISTERED IN U. S&S. PATENT OFFICE Magazine WRITTEN SO YOU CAN UNDERSTAND IT APRIL, 1926 No. 4 Sunspot Weather Prophets Vindicated Storms and Disturbances They Forecast Arrive on Schedule, but Whether Their Theory Is True Remains to Be Proven V\/eatee R prophets who forecast storms and intense cold for the past inter on the basis of sunspot activity uring tthe last three vears apparently ive been vindicated, and it now remains be seen whether the prophecy of a short nd cool summer for 1926 will be fulfilled. That sunspots influence the earth's eather, as well as magnetic, electric and ther atmospheric conditions, has been onceded for some time by most scientists, but the extent to which the known sun- pot evcles can be used to foretell weather months or even years in advance remains to be seen. The weather the increased changes which followed more outstanding developments. Why the spots which astronomers find at more o1 less regular intervals may affect weather on the earth is an interesting topic. The cause lies in the decrease in solar energy transmitted by the sun to the earth. The spots are caused by cyclonic storms sweeping across the sun’s surface. The storm is reflected at the margin of the sun by a vortex, or anti-cyclone, repre senting the axis of a high-pressure area The disturbance of the sun’s atmosphere by the storms is accompanied by displace ment due to the fact that the outer por tion is cooler, and as it moves downward it disturbs the equilibrium, producing greater density sunspot activ- itv in late No- vember and early Decem- ber, however, | left nothing for their most ar- lent devotee | to desire. Sud- den and sharp spells of in- tense cold, al- ternating with unseason- al mildness, ex- cessive rains, showers of meteorites, un- | usually large displays of the northern lights, consider- able volcanic activity abroad, and widespread and disastrous floods in Eng- land, France, Germany, Hol- land and Bel- at the base of the column. Long tongues of flame sweep out 250,000 to 300.000 miles past the sun's corona at al most unimag inable speed, while the cen ter of the cy clonic storm appears in the Astrea sd mer’s telescope as a vast black spot. Some of these storm centers are 50, OOO miles or | more across, and with their great size the resulting + | change in t he | amount ot! so- lar heat reach | ing the earth is |} quite marked. ee gium were only a few of the Naval Astronomers at the Washington Observatory with Part of the Camera Set Up to Photograph Sunspots As the sun re volves, the )

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530 POPULAR © U. & U. Gas Flames, Millions of Miles Long, Forming the Sun’s Corona, as Photo- graphed during the Eclipse a Year Ago; the Moon Is in Front; Eyepiece of a Great Telescope, and a Group of Sunspots, 175,000 Miles Long, near the Sun’s Equator spots sweep across it reaching a maximum intensity in from ten to twelve days, and gradually decreasing as they pass on to- ward the opposite side. The periods in which the spots ap- pear are variable, but are constantly growing shorter. The last minimum of sunspot activity was in 1923 and the next is due in 1929, if the six- eleven cycle continues true. The astro- nomical records show that the periods of maximum activity may be expected every eleven and three-tenths year, with periods of minimum activity within that period. British weather experts have found that in 1865, and for twenty-five years there- after, every fifth vear in England was wet, and that these years coincided with sun- spot activity. Then the flames began to appear oftener, and during the next quar- ter of a century every third year was wet. Between 1910 and 1921 the spots were still more frequent and alternate years were wet and dry. In 1921, there was a drought, and this apparently marked another change in the sunspot cycles, so that a new one is now being established. MECHANICS A similar study of dreught periods southern California shows that there ws floods in 1862, droughts in the seventic the greatest rainfall ever recorded there 1889; the driest period in 1898-99; anoth. heavy-rainfall year in 1914, and that 19 was the driest since 1898. Thus the fi period from 1862 to 1889 was twent seven years; the period of dryness, 187 to 1898, was twenty-six years; the seco wet extremes covered twenty-five year and the final dry limits were twenty-s years apart, so that the average was cl to twenty-six years for the extremes of t! interlocking wet and dry periods, and t] figure apparently marks the limits of tl weather cycles for that locality. Studi: in Australia indicate a weather cycle « between eighteen and twenty yea and the figures for India at virtually the same. Thi apparently indicate that weather cycl differ with the cality, but the sat basic factors 9 ern all of them. A California ol server, Father ] Ricart of Sant Clara, has advance the idea that ther: is a relation be tween the sunspot periods, the weathe: cycles, and the con junction of the planets Saturn an Jupiter. Like th drought cycles ot

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her unusual ¢ Much t two decades toward relating the cause rect, POPULAR MECHANICS 531 lia, India and Africa, this occurs twenty years. As the average ht period is three years, he brings rnia into his theory by adding the eriods at either end to the twenty- cycle, giving the twenty-six-years vce, The conjunction of the planets, lieves, causes an abnormal fall eteoric matter on the equa- region of the sun, causing ormous generation of which, rising in the of metallic gases, res the solar storms. ch periods, when the ts are in conjunction, ee few sunspots, but » feel the excess heat the sun, and a hot, ear is experienced. ears later there will opposition of the planets, and a smaller nstration of the same In the years between, rding to this theory, there smaller fall of foreign mat- onto the sun, and consequently cyclonic storms which sweep across re more visible, produce greater nges in solar radiation and we get the in cooler years and more rainfall. e possibility of the sun storms and nges being due to electrical or mag- - effects produced by the movements f other planets has been studied, but the is still in its infancy. Storms and occurrences on earth are itermath, apparently, of electrical dis- neces, but as they are the result, it is dly possible to learn much of their ori- from them, since the original cause already been dissipated. progress has been made in the effect of storms on earth and solar nomena, and scientists hope that, some they will solve both questions so roughly that the earth’s weather can orecast well in advance. That solu- 1, however, may not come within the hundred years, so slow is the prog- toward checking observations al- lv made. If Father Ricart’s theory is years of extreme drought will e in 1941, 1961, 1981, 2001, 2021, and on, in connection with the conjunction lupiter and Saturn, while minor t ughts will mark 1931, 1951, 1971, 1991 corresponding years later on. To e or disprove that theory beyond a t will take more than the lifetime ot CHANGES OF COLOR IN LEAVES LAID TO ALCOHOL Fermentation, which allows the red and yellow pigments to develop, is partly the Studying Leaves to Find Out Why They Change Color; Scien- tists Ascribe It Partly to Fermentation reason that leaves change their color in the fall, according to eastern scientists. By measuring the amount of light re flected from the leaves at different stages in their life, they have discovered that, during the summer, about ninety per cent of the sun’s illumination is absorbed, but in the fall most of it is shut out. This retards their growth, fermentation sets in, the alcohol absorbs the green elements and the bright reds, yellows and other shades appear. HOLDER FOR DRIVER’S LICENSE FITS AUTO-KEY RING Attached to the ring that holds the automobile ig nition keys, a tube with a lock cover, keeps the driver's license where it is handy for inspec tion at any time desired and is not likely to get lost. The extra mem- ber with the keys also reduces the likelihood of mislaying or losing them, yet the tube is not large enough to hinder ne now living. the driver in locking his car.

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532 Using Spring on Phone and Elec- tric-Iron Cords SPRING FOR ELECTRIC CORDS PREVENTS TWISTING Cords connecting the electric iron, the telephone or other instruments, are kept from knotting, breaking and getting in the way by a steel-spring section that takes up useless slack, holds the cord firmly so that it cannot twist and yet allows suffi- cient give to permit full use of the article to which it is attached. By protecting the insulation and outer covering, it reduces the probability of short circuits and the attendant danger of fire. POPULAR MECHANICS HALF OF WOMEN ON FARMs DRIVE AUTOMOBILES Survey of farm-home conditions in teen middle-western states reveals more than fifty per cent of the wome: the district drive automobiles. On other hand, more than sixty-seven cent still draw water from wells or pu outside the house, and less than twe: eight per cent have sinks with drain the kitchen. Less than eighteen per | of the homes surveyed had bathtul there were washing machines in 1 than forty per cent of the homes, and nearly seventeen per cent, the was were run from the farm-power sy Only a little more than eleven per ce: the farm wives kept any kind of recor their expenditures. OLD RESERVOIR AS THEATER HAS THREE-LEVEL STAGE With a seating capacity of 5,000 per an open-air theater constructed fro abandoned reservoir in an Illinois ci well suited to the presentation of cert plays, as the stage occupies three differ: levels. It is built upon the sloping sid the old water basin and permits almost stantaneous change of scene since the tains can be dropped on the setting at level and raised for a continuation of performance on the next, while in performances no curtains would be ne ed. Artists were hired by the city, w! owns the theater, to model it after t! constructed by the ancient Greeks. View of Open-Air Theater from Stage; Sloping Sides of Old Reservoir Simplified Construction of Tier Seats; There Is Room for 5,000 Spectators

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9) W yrs an American expedition plan- ning to fly over the North Pole, tarting at Alaska and ending in Spitz- rgen; Amundsen planning to try again th a dirigible airship, and an American squadron preparing to map 40,000 uare miles of Alaska’s most inaccessible untains from the air, the Far North gain is in the limelight. lwo or three foreign explorers have repared plans for airplane dashes into e Arctic, and may get under way before ummer., lhe race between Amundsen and the \merican party led by Capt. George H. Wilkins occupies the center of interest recause both hope to fly across the vast unexplored area lying between Alaska and the pole, which the MacMillan expedi- n failed to reach last year. Somewhere n this million square miles of territory is believed to be an island continent, whose nfluence has been recorded on the ocean les of northern Greenland. The one ho gets there first, if he finds land, may laim it for his country. The navy mapping expedition, while least spectacular, is fully as dangerous, if ot more so, than the polar dashes, and at ie same time will, if it succeeds, accom- lish work of incalculable value. The vernment has been trying for many POPULAR MECHANICS = a * Frozen North ) 533 yous Lo ongler { ’ ; = ™" Lieut. B. H. Wyatt, U. S. N., Who Will Command the Navy’s Alaskan Expedition, Taking Apparatus Aboard One of His Planes Preparatory to a Trial Flight at the San Diego Air Base Polar Expeditions and Navy Party, Outfitting to Photograph Alaska for Aerial Map, Mark Revived Interest in Arctic vears to get an accurate map of the little- known parts of Alaska, but conditions are so unfavorable, the mountains and forests so vast and the territory so unsettled that only a small part has been done. Forty picked officers and men from the navy air base at San Diego, equipped with four planes and a base ship, will attempt to make a complete aerial map of the 40,- 000 square miles lying between Ketchi kan and the Aleutian islands. The dis- trict one of the world’s worst flving spots. The warm air over the Japan cur- rent, striking the glacial mountains, pro- duces dense fogs throughout much of the summer, while the conflict of warm and cold air gives rise to a peculiarly violent air storm locally called the “willewaws,” which wrecked one of the round-the- world flyers and delayed the others. In this district are mountains rising three miles above the sea, deep and dark valleys, heavily wooded, an occasional small lake, and few, if any, spots where a plane may land on the ground. Three of the four photographic ships will be Loening amphibians, capable of landing either on water or land, giving the pilots a fair chance to glide to safety in event of engine trouble. The heavy amphibians, however, are sluggish in the upper air and lack the climbing ability to pass over is

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the highest mountain tops, so the fourth ship will be a small land machine, with interchangeable water pontoons. It has a “ceiling” of 18,000 feet, sufficient to fly over the 15,000-foot mountains at the proper height for taking the pictures needed for a mosaic map. Under the direction of Lieut. B. H. Wyatt, who made the 25,000-mile flight around the United States and pioneered in aerial weather-observation .work, the expedition has been quietly assembled at San Diego air base during the past several months. Three other lieutenants as fly- ers, a lieutenant commander as flight sur- geon, and an enlisted personnel of thirty- five men, including pilots, mechanics, cooks, radiomen, carpenters, machinists and other repair and maintenance ratings with five. expert aerial photographers, complete the party, while the mine layer “Gannet” has been assigned as base ship. Leaving San Diego shortly after May 1, the planes will be flown to Alaska, with stops at San Francisco, Seattle, Vancou- ver and Prince Rupert. Bases will be es- tablished at Ketchikan, Hydaberg, Wran- gell, Petersburg, Sitka, Juneau and Thane, and from them the vast territory, divided into strips, will be mapped. The fiving altitude for the work will range from 4,000 to 18,000 feet. The Wilkins polar expedition is already in the Far North, having left Seattle the latter part of January in order to get on the ground and be organized before sum- mer opens. The best time for the flight is during April or early May. Two big Fok- ker all-metal planes, specially built for the POPULAR MECHANICS work, were transported north in crat One is equipped with three high-power air-cooled motors and the other with single big water-cooled Liberty engi From the end of the government railr: at Nenana, where the planes will be u crated and assembled, the party plann to fly to Point Barrow, the jumping spot on the shore of the Arctic oc: Tons of supplies were forwarded by d and motor sledges during the late wint and early spring so that the ships wo not have to ferry their equipment to t! main base. Only one plane was to make the act flight across the pole, the other bei: taken along for preliminary work, and 1 permit the explorers to make a last-m ute. choice between the air and cooled systems after trying them out u der arctic conditions. Capt. Wilki: who was second in command to Vilhj mur Stefansson on his last arctic trip, a qualified pilot, but the actual flying « most of the trip is to be done by Car! Eielson, a pilot who has blazed the trails across Alaska for several years, lea ing Wilkins free to do the navigating a make observations of the terrain pass« over. Lieut. Eielson has flown more th 60,000 miles in the Arctic, at least thr times the distance covered by any ot! pilot in the Far North, and it was for t! reason that he was chosen by Wilki: During his Alaskan flying he carried t! mails regularly for the government, lan ing on the ice of frozen rivers and getti! through on schedule despite temperatur: far below zero. Bees asia Assembling the Engine Mount and Fuselage of One of the All-Metal Planes to Be Used by the Wilkins Expedition in the Attempt to Fly from Alaska across the North Pole water 1

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POPULAR MECHANICS o oo S| Unpacking the Machines and Assembling Them at San Diego for the Navy’s Expedition to Map 40,000 Square Miles of Unknown Alaska with Aerial Mapping Cameras iptain Stefansson, who took part in inizing the expedition, has high hopes it will succeed. The coldest weather be encountered between Fairbanks Point Barrow, he says, while the ac- | polar dash, from the shore of Alaska Spitzbergen, on the other side of the orld, will have temperatures higher than pt. Macready met on his altitude flights Dayton. The chief danger, Stefansson s,is that the plane may be forced down he last third of the air voyage, landing the ice, which drifts south and melts he warm Gulf stream. Should a land- be required at an earlier stage, Wilkins is confident that he and his companion can walk back to shore, armed with only a rifle, and live off the country on the way. His theories agree with those of Stefans son, but disagree with Amundsen’s, who maintains that an arctic expedition should carry sufficient reserve food for a round trip. Stefansson has lived off the country by shooting seals and other game for months, and Wilkins, on the last trip, shared his experiences. By not carrying large reserve supplies of food the plane will be able to transport much more gaso line and oil than did Amundsen’s ships on their unsuccessful trip last vear. TENT FOR CAMPERS HAS NO RIDGEPOLE Held by self - adjusting ers and springs and two llapsible uprights at each end, a tent, especial- ly suited to the auto tour- requires no ridgepole, 1, when not in use, folds intoa small bag. Each of e end supports consists telescoping sections of teel tubing, which fit thin each other. The nt has a detachable floor hich can be taken out for orough cleanings and no Is are needed to erect e tent. Tent’s Spring Supports Serve as Ridgepole

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536 Bombs’ Exhibited before House Military-Affairs Com- mittee; Black Objects Are Bounding Bombs Which Can Be Exploded Several Feet from Ground AIR TORPEDO CARRIES GASOLINE TO AID PLANE FLIGHT Containing a supply of gasoline in ad- dition to explosive, a bomb invented by an eastern man is intended to be attached to an airplane. It will hold sufficient gas for a journey of 1,000 miles, says the in- ventor. Besides this bomb, others which explode just before they reach the ground, and a special type of air depth bomb for use against submarines and other war- ships, were exhibited before the house military-affairs committee recently. ULTRAVIOLET-RAY TREATMENT SIMPLIFIED BY PAPER Beneficial baths of ultra- violet rays from sunlight may be had at greatly de- creased cost, it is expected, as the result of a discovery of an eastern scientist. He has found that a type of transparent wrapping pa- per, commonly used on candy bars, permits the rays to pass through just as does the clear but much more expensive quartz. Ordinary glass filters the sunlight, robbing it of the peculiar rays that have been found helpful in ‘ : : x “Rin-Tin-Tin,” treating children for rick- Movie Dog Hero Taking His Morning Exercise in Rev Cage While Trainer Urges Him to Greater Speed POPULAR MECHANICS ets and for various other medical , poses. An eastern hospital has a la quartz window, but it cost $15,000, $1,000 a pane, and it is this high cost quartz that has prevented the wide of the material. The paper is lars composed of cellulose, the substance forms the cell walls of plants, gives st ness to the wheat stalks and strength the tall spruce. Until further tests h been made, the scientist is unwilling state the degree of effectiveness that n be attained by the paper method. So | the experiments have been largely limit to the winter months when the ultravi rays are weaker than in summer so t continued trials are considered neces before definite conclusions can be dra as to the value of the discovery. DOG RUNS IN REVOLVING CAGE TO KEEP FIT FOR MOVIES Keeping the animal actors in trim motion-picture productions is one of important tasks of moviedom. “Rin-1 Tin,” the celebrated police-dog stat given morning exercise in a huge rev ing drum like a squirrel cage, to keep muscles firm, his senses alert and his g eral condition good. In a short time can pace the equivalent of a considera distance over ground; the trainer spared labor, and the dog is protect from injuries that he might suffer if were permitted to run around unleas! on motor-crowded streets for exercise

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POPULAR MECHANICS 537

OP... ¢ 4 “~ = aaee macazre % .' Pe ee

é & 5A rung ‘

scene at the Launching of the Huge Motor Vessel ‘Saturnia’; It Will Carry More Than 2,000 Persons be- sides a Crew of Several Hundred Men LATEST MONSTER MOTOR SHIP To steady the base, supports have been

BUILT IN TWENTY WEEKS attached to the roof of the work shop and connected to cross rods in the founda- ompleted in 140 working days, a rec- tion which is also strongly braced. | in shipbuilding, according to reports, ss motor vessel “Saturnia” has a carry- r capacity of 2,280 passengers, exclusive ARTIFICIAL FOGS GUARD CROPS the crew, besides 26,500 tons of cargo. FROM DAMAGE BY FROST S S , ic 5( 7 > r a6 . io _ n attain a speed of twenty-one knots. Purposes by a Scandinavian scientist, are . being put to peace-time use in Norway to protect crops from frost. The vapor BUILDING GIANT RELIEF MAP forms a blanket over trees, vines and TO TAKE THREE YEARS other growths, thus preventing freezing.

What will be one of ‘largest relief maps in e world is now under nstruction and is ex- ected to be completed three years. It will ww details of the en- area of the United tates and Canada. An ron-and-wood frame- rk was first built, ac- urately curved to corre- ond to the actual ape of the earth, and on this foundation the ip itself is to be placed, the form of a series of irefully molded and

ined plaster plaques. Building Curved Foundation for Huge Relief Map

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POPULAR MECHANICS { | | \ Eight Tugs, Side by Side, Fighting the Tide to Push a Huge Liner Around So That It Can Be Backed in‘ the Slip in the Background; Many Big Ships Require Even More Tugs to Dock Them

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\Ve've got to have With the Pilot and Tugboat Men .uffeuring Big Liners through New York Harbor and Boarding Them in Gales off Sandy Hook Require Skill and Daring By FLOYD TAYLOR 4 00-FOOT liner left her pier in the * North river not long ago, her nose wung down stream by tugs and she headed for the Ambrose channel. It hazy weather, but clear enough so the Jersey shore could be seen from hip. e pilot maneuvered to escape two |-hog” ferryboats and two barges d to the sides of a tug. The haze thicker as the ship was eased down river. Her nose poked past the tip of hattan island and slid into the upper or as a blanket of fog dropped n, so dense that those on the bridge In't see the bow. here’s nothin’ to call fog but a blan- of fog when it’s like that,” the pilot ed to the captain. You don’t have to tell me,” the cap- muttered. He was nervous. “You it going to take her down the channel this, of course.” ou bet I'm not. I’m going to anchor in the Statue of Liberty anchorage.” “This end of it is ; the last ship at anchor whose bell he had heard, and an anchor dropped from the bow. Hours later, when the fog had lifted, the captain and pilot, who had never left the bridge, found her in a good berth. So that one of the greatest liners could wait for safe weather, the pilot had executed a difficult maneuver through a fog so thick he could not see the ship’s bow. He did it in a space hardly big enough for the ship to turn around, in a harbor which has as dense traffic as any in the world. His work cost the ship’s owners about $200 but it may have saved them a million or more. The Sandy Hook pilot is a craftsman of the highest rank, fighting with a minimum of loss against storm, tide, shoals and fog, and against the vagaries of the ships themselves. Fog is his worst enemy. Some of the pilots would rather take their chance with a howling gale than with an ordinary fog. They are not always suc- cessful in fighting fog, but their percent- age of failure is amazingly small. Tide and wind of ships. I them this rning.” | know it. There iy be some in the er end now. ood luck. If we mt, well cut mebody in two go aground.” As the bells the ships at an- or sounded from tarboard, the pilot ung toward them bit. He edged the onster over until ' believed he was ending her exact- down the divid- ¢ line of the iannel and = an- horage. Steering the compass, he ent his boat ahead wly until he be- eved he had gone are jealous of the feats of fog in play- ing havoc in the harbor. In Decem- ber, 1923, they sent the finest passen- ger ship of the United States on the sand bar of Robbins Reef. The “Leviathan,” affec- tionately known as the “Levi” to many shipping men, was entering the upper bay. The wheel was swung to starboard and the ship didn't answer. It was swung hard over, engines were put at full speed re- verse. Still she kept going straight for the reef. The tide and wind had caught her nose and were more out 2,000 feet be- w the location of Off Sandy Hook; the Reserve Yawl of the Pilot’s As- sociation, Used When a Steamer Breaks Down powerful than her engines. 539

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540 POPULAR The boy who wants a Sandy Hook pilot's license is taken on as an appren- tice for five years’ work and study. If he can pass a severe examination at the end of that time, he is given a license to handle ships of eighteen-foot draft. He is a deputy pilot. Year by vear, if he passes his examinations, his grade is in- creased until, thirteen vears after he has entered the service, he can leap from a vawl off Sandy Hook for the end of a forty-foot rope ladder and climb it to bring in the “Leviathan” or “Majestic.” His job of handling ships in the harbor is only half the job—the other half is that of the tugboat men. The pilots share their expenses and earnings through a co-operative associa- tion. They work in rotation. There are about 100 pilots, and the number is lim- ited to 130. A pilot usually makes be- tween $300 and $350 a month. For pilot- ing a ship of over twenty-one-foot draft from Sandy Hook the twenty miles or so to her pier, the charge is $4.88 for each foot of draft. The pilot taking a ship down the har- bor boards her by walking up the gang- plank. From a pilot boat, it’s a different matter. There always is a pilot boat off Sandy Hook; even in an eighty-mile gale the pilots are there waiting. Last October a northeaster was blow- ing, kicking up a high sea. One of the 900-foot liners was coming in. Near the pilot boat she turned her beam to the wind, forming a lee. Down her side a rope ladder was dropped. The pilot boat crept up until she was about seventy-five feet from the liner’s side. Two appren- tices crawled into a yawl, after them a MECHANICS pilot, sixty-five years old, making one of the last trips before he retired. The yawl was dropped, the apprentices rowed desperately to get away from the pilot boat’s side before a swell could crush them against it. Halfway to steamer a wave flipped the yawl upside down. One of the apprentices managed to get on the keel and pull the other after him. The two pulled up the pilot. Another vawl left the pilot boat, res- cued the three and was rowed to the ship’s side. The old pilot, waiting his chance, leaped for the ladder. The ship rolled back and he dipped into the water until his shoulders were covered. As the vessel rolled the other way, he clambered a few steps, was dipped twice again a: finally reached the ship’s rail. That. day fifteen barges, torn from their moorings by the storm, were adrift the upper harbor and the Narrows. 1 pilots had to work the ships throu them to get to the docks. Pilots bring in ships in all sorts conditions. The “Arabic,” battered by storm, was brought through the Narro with a ten-degree list last fall. A freight er, on fire for three days and so hot her crew’s feet were burned walking on t! deck, was raced through the Narrows a Sandy Hook pilot and beached on th Red Hook flats. One of the pilots’ worst worries is t! swell caused by the ships they handle They must keep up a speed of thirte or fourteen knots to handle a big s! and a few knots more cause so mu suction behind her that it swamps sm craft and has been known to tear lo liners tied up at piers. One was tor! One of the Pilot Boats Which Cruise off the Harbor Mouth to Put Pilots Aboard Incoming Ships and Pic! Up Those Dropped by Outgoing Vessels; the Pilots Own Their Own Boats

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POPULAR MECHANICS winging the Mighty ““O m her lines not long ago and slammed inst the next pier, damaging both pier | ship. The Sandy Hook pilots handle ut thirty ships a day. On Saturdays are sometimes as many sixty ring or leaving the harbor. Damage is the curse of the tugboat iness. “If we scratch off more than » inches of paint docking a liner in ale against a strong flood tide,” a tug- sat captain said, “the company has to v—and the next ten generations are en over to the official inquiry.” \ tugboat man must be an apprentice three years before he can get a li- nse. There are about six tugboat com- nies in New York which have contracts docking big liners. These do little ere as lympic”’ of the White Star Line against the Tide, to Guide Her into the Slip; Tug- boat Captains Must Have Both Skill and Plenty of Daring general harbor work, almost nothing but docking. About a dozen tugs is the quota for the biggest ships, but under severe weather conditions as many as twenty have been used on the “Leviathan” and “Majestic.” Few landlubbers know that the gigantic liners must leave their docks in North river at full speed when the tide is run ning. They must, for once the stern of the ship outside her pier, the tide swings her so fast she must be clear in a few seconds or tear away part of her dock or the next one. If the tide is flood, the ship comes out at full speed with a half dozen tugs grim ly holding her stern against the tide to keep it from swinging upstream too fast. 1S — a a gt a Picking Up the Pilots of Outbound Ships; the Pilo Will Go On and Drop a Second to t Vessel Has Dropped One Gig for the First Pilot and Run in Alongside of the Other Steamer

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542 The moment the bow is clear of the dock, the engines are started at full speed ahead to check momentum, otherwise the ship would ram the Jersey shore. Once the liner is in the river, the tugs straighten her out, the lines are dropped, and she down the harbor under her own power, in charge of the pilot. In bring- ing a ship to dock, the tugs take charge a few hundred feet from her pier. If the tide is coming in, her nose is headed into the pier opening, the tugs let the tide swing her until she is parallel with her pier and her own turbines slide her in. When the tide is flood, she is taken upstream, above the pier, and turned around before being docked. voes The liner “Columbia” backed out of her dock one day at the foot of West Twenty-Fourth street and was headed down the river as the “Majestic” started from her pier near the foot of Eighteenth street. The pilot of the “Columbia” found a swirl of the tide was swinging his ship into the “Majestic.” He had the wheel thrown hard to starboard and the engines speeded to give her steerage wav. The tugs at the stern of the “Majestic” puffed, portentously at first and then rapidly. The “Columbia” missed the “Majestic,” but hit a pier on the Jer- sey shore, ripping off a corner of it. The “Mauretania” once was_ being pushed into her dock at Fourteenth street and seemed safely inside when the tide got the better of the tugboats and slammed her against the pier. The over- POPULAR MECHANICS hang of the navigation bridge struck vertical girder supporting the roof of t! pier. There was a report like a giant firecracker exploding. The captain the “Mauretania” leaped a fraction of a second before a section of steel, ten feet long, from the pier structure was flu: where he had stood. “That's a ‘crack,’ that is,” the tugboat captain on the bridge said. “Crack” the tugboat man’s word for accident. But there are few such accidents, and there has never been a bad one. On the rare occasions when a liner hit a pier with considerable momentum there isn’t much pier left. It’s hit with too man) thousand tons. A tugboat captain, ex plaining that, said: “There never was a really bad job done on docking any of those big ships. If there ever is a bad job, a real bad one, the ‘L« viathan,’ the ‘Majestic’ or the ‘Berengari will cut Manhattan island right in two.” FOXES BEING RAISED FOR FUR PREFER FRESH-FRUIT DIET Oranges and apples are the favorite food of foxes being raised at a fur fart near Los Angeles. The animals receive regular rations of bread and milk with an occasional treat of eggs and raw meat The fruit is served as “dessert,” and bought in large quantities. Foxes that are destined for fur are fed a richer diet than the others, and they are killed i December when the pelts are at their best os a J Boarding a Vessel off Sandy Hook in Calm Weather Is a Comparatively Easy Task, but, Calm or Rough, the Pilot Must Get Aboard, and If He Falls into the Sea, Another Takes.dis Place

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POPULAR MECHANICS 543 bia University Oarsmen Use Gymnasium Swimming Pool for Early Crew Practice; Form and Team- work Were the Objectives; Braces Kept the Hull from Bumping against Sides of Pool CREW ROWS IN SWIMMING POOL TO PRACTICE FOR RACES lates for the Columbia university oved early practice for the racing this year, even though ice pre outdoor training. A special hul! tructed and tied to the sides of a sium swimming pool. Oars were d in regulation fashion, and the under the direction of coaches, | almost as much benefit from the rills with this equipment as would een derived from shorter periods n the river. Since the hull was ry and a close view of each oars- is possible, the drill became more e, and errors in the stroke of any the men cou!d easily be detected. MEASLES SERUM FROM ADULTS AIDS CHILDREN ired from the blood of adults who asles in childhood, a serum that is modify the severity of.the disease lren and to give them immunity for reported from France. Its dis- was made during a shortage in the r preparations, and more than 1,000 ms are said to have been given any bad effects. The disease is if reported to have caused more than 1,000, 009 deaths in Europe between 1900 and 1910 and within the death-registration area of the United States, it claimed more than 100,000 victims from 1901 to 1920. Statistics from the more important coun tries show that the death rate from measles is falling more slowly than that from diphtheria, smallpox, scarlet and whooping cough. fever SPRING HOLDER FOR PIPE STEM KEEPS BOWL UPRIGHT Easily slipped up- on the pipe stem, a spring bracket, with short legs at each side, keeps the bowl from tipping when the pipe i placed upona table or other surface, and protects the bit from breakage. It can be carried in the pocket when not in use or left on permanently, as it does not in any way interfere with the smoker. also eA thirty baseball bat can be seconds in completed in a modern plant.

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544 POPULAR MECHANICS

~ tilation, he is of} 4 La faryh Institute of techn

rH opinion that it Ty +e; more improbable to se da] heat waves in this ner than it was to b1

. cast sound waves, by 7 that instruments 1 f- be discovered for erly controlling waves, picking the: a holding and ampli them. He visions central plants fr which heat will be sent direct to homes and fice buildings. The tem will largely eli: nate pollution of the mosphere by smoke serve fuel supplies save labor, the prof points out. Like

Workmen Testing Strength of Life Net Stretched under Dome to Catch Any- one Who Might Fall from Scaffolding as Building Progressed ROPE NET UNDER ROOF OF DOME PROTECTS WORKERS One of the safeguards used to protect workmen building a huge dome over a building in Berlin, Germany, was a net of rope stretched, spiderweb-fashion, where it would catch anyone who fell. The strands were woven closely enough to prevent a person from slipping through, but provided sufficient slack to break the force of a fall. HOMES TO BE HEATED BY RADIO SCIENTIST PREDICTS Broadcasting heat waves by radio will be a reality within a few years in the opin ion of Prof. E. S. Dib- ble of the Carnegie

radio, heat waves through space through solids, and man learns how ti trol them, heating throughout the will be revolutionized, the scientist © Gilliams’ Service “SNAP-THE-WHIP” WITH MOTOR LATEST WINTER SPORT Skaters on a New York city pond « joyed the ancient sport of “crac! whip” with a modern twist last motive power being furnished by a ole cylinder one-wheeled motorcycle whisked as many as thirty person time in a speed chain over the sn ice. A rough tire afforded the nec: traction and the cycle is said to hai tained a speed of forty-five miles an Sharper turns as well as faster slidi1 possible with this Persons Lined Twenty-Five “Snap” behind Motor Wh«

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in Venice Is Doomed Jestruction, According Canals Are to Filled for Roads orts CANALS OF AMERICAN VENICE TO BE FILLED FOR STREETS ice its annexation to Los Angeles, the b of Venice, Calif., is facing drastic It is reported that the water ivs of the town, modeled after the of its Italian namesake, are to be up and transformed into ordinary Boating and swimming in the have been favorite pastimes, and iterwavs have also served as for motion pictures. CS. scenic . 5 | unds EXTENSION ON TRUCK TRAILER HANDLES LONG PIECES e capacity of an ordinary fifteen-foot k trailer is practically doubled by the ion of removable extensions consist of a series ns, pipe supports stanchions. itty-foot lengths n be hauled with equipment, and en the pieces are re unloaded, the ins are removed, ving the units to p down where ev can easily be | with a cable and igged to the place sired, or dumped iply by running tractor forward. + ' ot Detachable Extension of POPULAR MECHANICS o45 Hauling of Long Pieces in Motor Truck Rollers in the trailer bed help this action, allowing the load to slip out eas- Enough steel can be hauled in one trailer, with this addition, for the erection of two 100-foot towers power pur- poses. \ partition keeps pieces for each tower separate in the trailer ily. for INDIANS DIG FOR QUICKSILVER SIRES USED FOR PAINT of blood-red ore that lie rugged mountains in southwestern ire still being sought by Stores under Texas Indians, but not for war paint. The modern tribesman digs for the mercury which is extracted from the ore. For thirty vears, the mines in this region have been worked, one com pany having produced $10,000,000 worth of quicksilver during the last quarter cen Indians and mining vil inhabit the remain tombs Mexicans which silent tury. small as dur ing the daytime while the men are working far below the surface As of the earth. In one of the mines is a large cavern reached by a fifty-foot lad der, Pp laced there years ago by the primitive tribes. Surrounding bluffs are decorated in In- dian designs drawn in red pigment which is prepared from the ore. Pipes and Chains Permits

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546 CHAIR STILTS KEEP FEET DRY CROSSING FLOODED STREET Rather than Dampen His Feet, This Citizen Used Chairs as Stilts to Cross Flooded Street Supported on chairs which he lifted and replaced after each step, a resident of Liege, Belgium, kept his feet dry while crossing a flooded street and spared him- self the risk of falling from ordinary stilts. Irregularities in the pavement added to the difficulty of the stunt, but since each chair had four legs the ingenious traveler met with no mishap. SPIRAL PUMP LIFTS HEAVY OIL FOR BUILDING ROADS One of the perplexing problems of the oil industry has been how to get the heavy, sticky grades, useful as ingredients in mak- ing roads, out of the ground. A western inventor has devised a pump which is re- ported to offer a solution and requires no heating in the hole. It is a spiral af- fair without valves and, with only a ten- horsepower engine, has been lifting a heavy grade of oil from a depth of 400 feet. Its capacity is from 300 to 400 bar- rels a day of this quality, but would be larger with lighter kinds. The spiral is continuous from top to bottom and has an inside shaft working in the opposite direc- tion, operating a feeder which obtains the supply at the base of the well. The oil POPULAR MECHANICS comes up mixed with sand, shale other substances which are separat a refinery. A small amount of ga lubricating oil is also extracted, le a residue valuable in surfacing road i | FARMYARD FOR FISH At Neilsen, on the Danish islan Zealand, an artificial lake, covering proximately 500 acres, has been for for the raising of edible eels. Pumps been installed to supply salt water to | fish, and a special passage has bee: ranged with fresh water flowing ou sea to attract the voung eels, or. “ely: as they are called, to the submarine {| The creatures are easily fed, grow ly and command good market pr Raising them is an important indust: Germany. Before the war, more 17,000,000 young fry were taken Epney on the Severn in England to ply the German farms. About 1,(\! required to stock an acre, and they to marketable size in three to four CROOK AND JACKET AID POLICE IN RESCUE OF FOG VICTIMS London policemen traveling the districts have been equipped with cr and special life-saving jackets to them in rescuing persons who tal! the water during dense fogs. A | pro\ ful pocket seatchlight is also Ready to Rescue Fog Victims; London Policema Crook, Life Jacket and Flashlight The crook is long enough to reach a pier to the water or several feet be its surface and also helps the police find his way in the darkness.

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POPULAR MECHANICS

What Your. Dog Really Knows

By FRED ] dog wag his tail? way and abilities which in their wild state ind in their own way People have neariv so mu they had alre learned amor themselves Dogs get most of their traits from savage ancestor wolves, jackals, and the like, and pos- sibly from Austra lian dingoes. True, a few naturalists doubt that dogs are dese ended irom wolves or jackals but hold that their ancestors were <«

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548 POPULAR MECHANICS a strictly canine species now extinct. on signals and get these up all at o1 However, the wolf and jackal theory is but evolved them gradually as their nx plausible enough. demanded. Most important of these In their wild state dogs had to work in _ their bark, to call the rest of the pack packs, because the food problem was often gether. Whenever one caught a scent serious, and they had to attack larger ani- game, a few loud barks brought ot mals than it would have been possible for dogs who might be interested. | any one individually to kill if he had gone though certain members of the on his own hook, after the manner of a were not on any too friendly terms feline. some of the others, they had sense eno Many of us could probably take lessons to know that it was to their self-inte: from primitive dogs in rec- ognizing the advantage of subordinating self for the common good. Dogs must have been smarter than cer- tain other animals, even in the beginning, or else they wouldn't have had sense enough to see the gain in co- operation. To work together effec- tively, those wild forebears of our own dogs had to have a svstem of signals. They didn’t appoint a committee t - Louisiana Man, Has Made a World’s Record High Jump of Twe aa Feet Two Inches; He Is Also Reputed to Be the Fastest Dog A the United States, Having Won the Famous Futurity of the 5: — —_ a “Rambling Gold,” an English Coursing Hound Owned_by Yi west against a Field of 126 Dogs

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POPULAR MECHANICS ork in harmony and unity until the had been overtaken and captured - that, if they wished to stop co-oper and fight over the dividing up of the it didn’t matter much. Dogs of a agreed on the kind of bark that nt to get together and help. Even any average dog has several kinds harks for different occasions—prob- more different kinds than his human ciates realize. There is the bark of of excitement, hatred, doubt, and Being capable of nearly every hu emotion—love, jealousy, hope, cour- timidity, and many more—he prob can give voice to every one. But few have our ears finely enough tuned ivs to distinguish one from another. ssibly the dog acquired from his hu associates the ability to express him especially by the pitch of the voice. in, when irritated or impatient, is in el to speak in a high-pitched voice, it is to be noted that dogs do the e thing. \side from many re may be another reason for a « Lloyd Morgan, famous British ident of animal intelligence, suggests it is a means by which each in- ites to the other the fact of his forting presence. “The _ bleat- of lambs at the hour of dusk, lowing of contented cattle, chirping of the call notes of the crating hosts of birds, x these, whatever else may be, are the reassur- ocial links of sound, the teful signs of friendly kin ‘| presence.” But the bark wasn’t the dog’s only ynal. There were times when a rk would have scared the game iy before the whole pack could rrive on the trail. It was necessary, en, to have a silent signal. For a dog’s tail was a handy contrivance uppose that’s what the tail was really ide for—to wave information to other gs approaching from the rear and aid getting better co-operation. When se on the scent of game, a wise dog igs his tail as rapidly as possible. He loesn't give much thought to this loesn’t have to; he simply follows the in tincts inherited from early kinsfolk 'Younds seem to make an especial point ! this tail wagging when chasing some- thing. As the scent of the trail grows lore promising, they not only wag their tails but carry them as high as possible. practical purposes, “Se iog s grasshop- 549 Eleven Ounces of Wire-Haired Jap anese Pong, Claimed as the World's Smallest Dog lta d o's tail happen to white at the end, then the signal becomes all the more noticeable. Why do farm dogs bring home the cows with so little teaching? Bringing cows home g is much like hunting, except Y that there isn’t any killing Naturalists say that dogs used w to circle about and round up the | animals they intended to kill, and so it comes natural for certain reeds of dogs to work with cattle It is not uncommon for dogs to be more capable of performing a task than of ce ciding when not to do it. \ good watcl dog is valuable not because he bites anv body who comes near, but because he acquires an astonishing degree of discre tion and somehow knows which visitors not to bite. It isn’t necessary to teach a dog to guard his home. He inherited that instinct. Indeed, it is one of the oldest instincts he has. When dogs lived in dens, they barked for self-protection when an intruder came near. Dogs that failed to do this risked being killed by their enemies. By process of natural se

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550 lection, nearly every dog became a watch- dog. Those that did not readily bark sig- nals of warning were sooner or later killed. However, even in the wild state, dogs learned to know that certain stran- gers were harmless. Tame wolves will guard a house but will let regular callers come and go without paying any atten- tion to them. The bark of a watchdog is for two pur- poses—to scare away anyone who doesn’t belong, and to notify other dogs to come to his assistance. This latter is more tra- ditional than useful, as most people do not keep more than one watchdog, and there aren’t any other dogs: on the same premises to come to aid. But because of their primal instincts, other dogs in the neighborhood answer the bark just the same, especially if it’s in the middle of the night. We humans are inclined to have a low opinion of men who are bluffers. With dogs it is a little different. Some of the most sensible dogs do a lot of bluffing. A big bark not seldom saves a bite or bloodshed. If it is useful for a dog to impress an- other dog with his ferocity, it is equally useful to show a dog when he is friendly. A courageous dog will keep on fight- ing as long as there is an ounce of strength in him. But even a good fighter often realizes that discretion is the better part of valor. When a dog The Dogs of Belgium and Holland Are Taught to Work; Here Is a Milkman on His Rounds much bigger than himself walks up to him in a threatening manner, he is likely to roll over on his back in an attitude of complete submission, knowing that a dog has enough sense of decency not to bite another dog when he thus gives up. A big dog will seldom bite a smaller dog un- less the little dog bites him first. But POPULAR MECHANICS little dogs often take advantage oi immunity and run up to big dogs, b ing as if bent on murder. This seen be merely a form of showing off. A dog evidently likes to have the neigh see how brave he is when danger is 1 apparent than real. Nearly everybody must that a dog ordinarily when he growls, but holds his head | when barking. A growl means a pos fight, and a dog instinctively .lowers head to guard his throat. But a b doesn’t necessarily bode ill and a d vocal cords work bétter when he ra his head. It is almost impossible for dog to bark well when lying on his ba I taught one dog to bark for a piece meat and also to play dead on comma Then I tried to combine these two acco plishments. The dog tried to bark w on his back, but he had sach difficu that his efforts were laughable. The disposition to growl at any ot! dog near the food supply is have not lowers his | ) A An tt EERE een % SY Bax one of the most deep-seated of dog trai because, at one time, if a dog let hims« be too easily imposed on and lost his sha of victuals, it was a question of life death. In many respects dogs exhibit bett 4

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POPULAR MECHANICS 551 wt ¢ >) = s+ The St. Bernard Is Rapidly Becoming Extinct, Being Too Big for Modern City Life; Here Is a Picture of Five Champions at One of the Few American Kennels Still Raising Them ilgment than we do—particularly about A dog never eats just because meal time. He eats only when hun- If he doesn’t feel just right, he lets «| alone, no matter how tempting it ks. Moreover, when he is hungry and assortment of food is placed before m, he picks out the thing he likes best d eats it first, instead of it for nes ng. ] saVINeE sert after he’s all filled up with other ings. People often laugh at dogs and say ey have food on their minds all the ie. This is true, ina way, because dogs ve a limited number of pleasures and ttle opportunity for intellectual enjoy- ent. Food is less important to us be- use we can always manage to obtain od when we need it. With dogs, food nt always so sure. Away back yonder the earlier days of the species, they isually had to risk their lives for food before they got it. No wonder food seems ) them so important. We sometimes deplore a dog’s habit of bolting his food—swallowing a large 1 , , chun one gulp of meat at stomach is built te digest food eaten thus hastily. It had to be so in his wild state, that he might eat. hurriedly while pur- sued by his enemies. Moreover, if the pack brought down a large animal and an overpolite dog waited to chew each bite before swallowing, the others might greedily eat his share as well as their own. Because of human vanity, one of the things most sous in a dog is the so- called “one-man” quality. ‘It flatters the master to have even a dog show a marked preference for his society. A dog does this readily enough because of his old instinct to follow the leader of the pack. Why not, people ask, one-woman dogs as well as one-man dogs? There are. A dog will follow a woman as readily as he would a man, provided she is really the leader of the household. It is hard to fool dogs about who is the boss. In the long run, dogs seem more likely to take up with men because men do more of the things that enjoy doing, such hunting and going on long hikes. dogs as

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It is possible to exaggerate the sense of loyalty to his master a dog has. So op- posed is the dog to being left alone, and so disposed by hereditary instincts to follow a leader, that he readily adopts a master and gives him whole-hearted de- votion; but, nevertheless, it is not diffi- cult for a dog to take up with a new mas- ter. After a week or two, he may be just as loyal to the new one as he was to his previous owner. Everybody who has a dog has noticed him turning around two or three times before lying down—exactly as he would do if making a bed for himself in tall grass that must be flattened out before it can be comfortable. A dog is fussy about his bed. If compelled to lie on bare ground, he may scoop out enough earth with his paws to make a hollow somewhat corre- sponding to the shape of his body. It is barely possible, as one naturalist suggests, that another reason why this habit of turning around has survived so long, is that the practice had so-called Fcaedll an ‘ Another Working Dog of Belgium Who Trots in This Treadmill to Furnish the Power Which Daily Churns t! Butter and Operates Other Household Appliances 552 POPULAR MECHANICS elimination value; that is to say, i: wild state those dogs that did not d failed to escape the attention of thei: emies, or possibly of snakes hidden in grass, and perished. This idea, tho: seems far-fetched. It is more likely the practice is merely a habit based the need of mashing down the grass f comfortable bed. Most people understand, that a pants, not because he is out of bre but because he is warm and the sw: glands are in his tongue. Why does a dog bark at the moon’ Possibly because in ancient days used to hunt by moonlight and set uj; signal to call other dogs to join him You may have observed your dog co ing his head to one side when hear strange sounds. This habit—especi: noticeable in puppies—seems to be due the fact that during many generati dogs have found it necessary to prick their ears and put them at the most vantageous angle to catch sounds

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POPULAR MECHANICS cer. When trving to see an object, irally dogs also try to hear it. Thus grown up a relation between their . = ~~, es and ears with the result that dogs ually prick up their ears when looking ntensely at an object. Not only that, but a dog is quite likely to raise his nose nd sniff on hearing a strange sound. 553 Director of a Clever Series of Animal Com- edies Surrounded by His Actors; Painstak- ing Care and the Affec- tiorm of the Animals Are the Main Requisites in Producing These Movies Nearly every dog owner, I suppose, has amused himself by making a queer sound with his mouth to cause his dog to turn his head to one side and then sniff. Since the dog lives in a world of smell, the moment he hears a strange sound he tries to use his nose as well as his ears because he has found his devendable. nose is more LANTERN SLIDES AS TEXTBOOKS ADD INTEREST TO LESSONS Grade pupils attending a Wisconsin chool enjoy the pleasures of a picture iow while learning to read and “do ums,” for their teacher uses lantern slides a substitute for classroom textbooks. ihe method is said to increase the pupils’ nterest, speeds their progress and, ac- rding to the superintendent, can be idapted to work in the upper grades and igh schools. First reading lessons con- ist in practice with the names of the arts of animals, which are written upon i slide with a picture of the creature tudied. The pupils are taught to associ- te the word with the illustration and oon learn to recognize the names with- ut the slide. Arithmetic problems are worked from pictures of a grocery win- low display in which the various articles ior sale carry price tags. The pupil is isked, for instance, how many things he can buy for a dollar, and similar exercises are given in subtraction, multiplication and division. GOGGLES WITH WATER POCKETS CLEANED BY NODDING HEAD Rubber goggles, intended especially for laboratory workers to protect the eyes from dangerous dust or fumes, have pocl ets between the lenses in which a small quantity of water is placed to keep the glass clear \ nod or shake oi the head bathes the surfaces and the water falls back into the cups below where it cannot interfere with vi- sion. This eliminates the necessity of removing the goggles to clean them, a step which might be attended with dan- ger in performing certain experiments.

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554 POPULAR MECHANI( MODEL STORE ON MOTORCYCLE § One producer declares that the radio play CARRIES CANDY ORDERS is a “series of sound pictures printed on the film of time.” Patrons he regards as . = To help “eavesdroppers listening in on real life.” advertise his Shakespeare was a natural writer of “radio scenarios,” this authority believ: but the work of almost all pla wrights must be completely reco: structed before it is suitable presentation over the micropho: For that reason, the deve! opment of a special radio er, cr playwright is urged. O; =e, 7 “2 - we sy a —— J of the tasks is to harmo: ize the three kinds of = sounds which are the chief eG ingredients of the radio PANG \\ drama: music, speech and accessory noises. It | —— been found that about thirty-five minutes is Little Candy Store on Wheels; Model Is Reproduction of the Real Building long as the attention ot and Holds Packages for Delivery the listener can be held by a radio play, so that skill wares, a western candy merchant has con is required in condensing works that re structed a model reproduction of his bun quire thrice as much time for ordinat gsalow store as the sidecar of the motor- stage production. Another problem is to evele with which delivery of orders is determine what instrument to use to im made. The arrangement not only attracts tate sounds to get the best reception. At attention, but protects the goods within. tention is also given to the pause, whi is as effective in radio as in the visib TRICKS IN ART OF RADIO DRAMA “T#S¢ drama., GIVE EFFECTIVE RESULTS Breaking toothpicks sound like crashing forest trees; an insect’s buzzing passes for the roar of a wild animal, and breathing into a lamp chimney con veys the impres- RUBBER-BAND PACKAGE TIER SAVES TIME For stores, offices or homes j triangular holder, with a supp : of rubber bands the base, permit tying packages ot various sizes in few seconds; doe away with the bother of strit and keeps the ban where they are n likely to get lost The bundle is sin ply placed on top the holder with th: left hand end band drawn over it with the right About 900 rubbe make a pound the size recom mended for pac! age use, and the may be cut at the rate of 20,000 a: i hour from tubes i Drawing Band over Package from Holder a power outfit. sion of a terrific windstorm to lis- teners miles away, while a mop swished around in a pail is heard as a hurricane raging at sea. These are a few of the devices that the producers of radio dramas have developed as aids to the ether plays. This-form of presentation is regarded as a new art, as distinctive as the motion pic- ture and as differ- ent from ordinary stage work as the film story is from the printed page.

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2ECORD SOUND OF QUAKE TO GIVE WARNING }y means of a sensitive electric paratus a Japanese scientist has veloped, approaching earth- takes are said to be translated to sound several seconds before e actual shock. With this uipment, the inventor declares, would be possible to send the ining by wireless to distant rts of the world so that knowl- ce of the quake would be im- rted although its tremors would ‘too faint to register upon seis- graphs. The outfit consists incipally of a pendulum, an ectric coil and an amplifier. The ndulum is so delicately hung it it reacts-to the slightest hori- ntal or vertical motion. When is set in motion, it affects the t of the apparatus in such a iy that a warning sound is pro- uced through the electric coil d amplified by the loud-speaker rangement. Tests showed that ich slight vibrations as were used by tapping on a table or ikking across the room, actu- ted the mechanism. A great POPULAR MECHANICS 555 benefit seen in the invention is that it might aid scientists in pre- ‘ting quakes by informing them i others near or far away, so that warn ngs could be issued in time. LEVER MORTISER FOR HINGES SAVES CARPENTER’S TIME Hinges for cupboards, windows or ors can be mortised in, without trac ng or using a butt gauge, in not more than a minute each, it is said, by using an djustable tool now on the market. It fixed to cut in almost any kind of wood, n be accurately set for width and fool in Place for Cutting Out Mortise for Hinge; Blade Is Adjustable to Different Depths epth, and since it makes exactly the same ize cut for each hinge, it prevents the loors from binding when they are hung. Courtesy The Graphic Hoisting One of the Huge Stone Horses to Its Position on the Palace of Justice in Rome RAISING OF HUGE STONE HORSE TESTS ENGINEERS’ SKILL With modern hoisting equipment, pon- derous steel beams, heavy safes and other large objects are raised with comparative ease, but in placing the huge stone horses on the Palace of Justice in Rome, several unusual difficulties were encountered. To protect the sculptures from damage, chains were tied about the horses’ that the statues could be swung away from the walls and prevent breakage. The irregular shape of the load made it hard to balance, and the placing had to be done around and through a network of specially designed scaffolding. feet so CITY TRAFFIC-SIGNAL BELLS REPLACE ALARM CLOCKS Lodgers at hotels in the downtown sec- tion of a Texas city report that they have no further use for alarm clocks, for they are awakened at seven o'clock by the clang of traffic-bell signals on the streets outside. Their clamor is_ sufficiently loud to rouse sleepers in several of the smaller hotels near street intersections.

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556 POPULAR MECHANICS Birds and Elephants, Tigers and Snakes, Picture Films and Grand Pianos, All Kinds of Merchandise Come to Aerial-Freight Man By CY CALDWELL A LARGE circus advertised as a star at- . traction the “Missing Link,’ a chim- who could smoke, dance, drink, roller-skate and eat at a table. When city and countryside have been billed with pictures of this creature, nothing must prevent his making an appearance, both afternoon and evening. In this mod- ern age of speed not even death itself can interfere with a performance. As _ wit- ness the case of “Bongo,” the chimpanzee who died while the circus route to Toledo. The mere tact that was no reason why Toledo audiences should be deprived of seeing him alive and in good health, however, for in New York city there was a man who trained chimpanzees and had one on hand at the time. He was communicated with by telephone; a pilot and airplane were hired in New York, and within two hours the animal was speeding westward at some ninety miles an hour. And when the show went on, there was “Bongo” panzee train was en “Bongo” was gone at his little table having afternoon with none of the spectators any the \ “Bongo” was just one of the mar strange cargoes that have been carri in airplanes. Snakes, lions, tigers, d« cats, bears, kangaroos, and even e phants, have been transported by Sometimes the animals were urgently quired for a circus or show; at other they were carried in connection with so advertising stunt. I may not be credit with a love of truth when I| state that elephant has been taken for a flight. B if I am not believed at once, it 1 o1 because the word “elephant” immediate presents to the reader the mental pictu of a massive creature weighing tons. must be remembered that every big el phant was a little elephant once. Catc him young and he is quite eligible as passenger—provided he is in a crate is securely roped. A small elephant h been carried in an airplane as an adve tising stunt, and in quite a small plane that. Such a plane as the big Barli

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POPULAR MECHANICS . aes from New York These Air Goliaths The Big Double-Motored Si- 7 korsky Plane in Which Two Baby-Grand Pianos Were Trans- ashington; Articles Weighing a Ton or More Are Speedily De- livered at Distant oints by to — With a 650-Horsepower Mo- 7 tor, This Huge Single-En- gined Ship Will Carry Sixteen Persons and Baggage at 110 Miles an Hour t t “2 —

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558 POPULAR MECHANICS

bomber could carry a grown elephant. apparently take a keen interest in This plane has climbed to a height of scenery as it passed below him. nearly a mile, carrving a load of 8818 Later, when the British govern: pounds, or nearly four and a half tons, placed an embargo on all dogs coming Dogs and cats are frequent aerial pas- from France on account of an epide sengers. “Ike,” a cat owned by the air- of rabies, English pilots ferrying old mail pilots at Cleveland, crawled into the planes back from France for use in tr tail ofa mail plane and flew to Bellefonte. ing squadrons in England, were in the Dogs especially seem as fond of travel habit of bringing a dog or two nearly in planes as they are in automobiles. Dur- every trip. There was considerable de- ing the war, an English ferry pilot— mand for Belgian police dogs at the time one who delivers planes from the depots — so the pilots augmented their slender war to the service squadrons—had a fox ter- wages by entering the dog business, en rier who was a constant aviator. THle bargo or no. It might be just whispered would ride on his owner’s lap every trip, in passing that many cases of expensive and would bark and show extreme dis- French wines flew calmly over the cus- appointment if he was made to stay be- tomhouse at Folkestone, and landed { hind. During flight he would place his — ther inland. fore paws on the side of the cockpit, and In Belgium, racing pigeons are trans ported by air in a _ specially designed ers Pana. plane, not for advertising but merely vt be cause it is more comfortable and less < ~ a. 7 ing for the birds. A flock of racing me pigeons sent in hampers 500 miles \ from their home by train arrive tired and dispirited. They have spent at least a day and a nig sometimes more, in a_ hat stowed in a baggage van: haps they have had _ seve changes of trains, necessitat the disturbance and fright of ing handled and thrown arou

Lashed over the Front Cock- pit, This Talking Machine Was Rushed to a istant Dealer

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POPULAR MECHANICS 559 Photopress i plane, on the other hand, they are put their little compartments, have fresh air | light all the journey, which takes only e hours instead of perhaps thirty, and rive in perfect condition for their re- rn flight on their own power. Nearly everything in the world, not ex- uded by bulk or weight, has been flown mewhere by someone. Animals, birds, dies’ dresses, pictures, motor cars, parts machinery, fire-fighting pumps and se, pianos, phonographs, cameras, serums, whisky and contraband Chinamen, are some of these. The Canadian government forest-pa- trol planes carry as standard equipment gasoline-driven fire-fighting pump, and everal hundred feet of hose. They are equipped like a harbor fireboat, though n a small scale, and can put out any mall forest fire in the early stages. In iddition they carry, according to their ize, from three to ten. fire rangers. A frequent cargo in this country is pictures and news reels of important events, for the transport of which the photo syndicates are willing to pay fancy prices—from fifty to seventy-five cents ruce rugs, P Twenty Passengers Were Served a Complete Lunch in This Big Vickers Passenger Liner a mile each way the round trip, ac- cording to the type of plane used. The Dempsey-Carpentier fight, the republican and democratic conventions, the Tennes- see evolution trial, the world series, the “Shenandoah” disaster and the Santa Barbara earthquake are a few of the events of which airplanes carried pictures. The nice thing about pictures, from t] pilot’s viewpoint, is that they weigh little and take up no room. The worst thing to carry is something too large to go inside the airplane. Recently I carried a big cabinet-sized phonograph from Philadel- phia to Cleveland, tied across the fuselage, or body, of an ordinary small plane. It stuck out a foot on either side and shut out all view forward. This is called “fly- ing blind,” and is not advisable. In large planes this difficulty does not occur, for the baggage compartment is sufficiently roomy to carry the goods in- side, where they should be carried, not out in front of the pilot or tied to a wing. A disassembled Ford roadster has been shipped from Detroit to Cleveland; and an Essex coach, assembled and ready to have

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560 POPULAR MECHANICS run, has been flown in the Remington- Burnelli air liner, with plenty of room for passengers besides. The twin-motored Sikorsky plane recently carried two grand pianos, together, from New York to Washington. The Ford planes make daily flights from Detroit to Chicago and Cleveland with parts, half a ton each trip. In advertising flights, the passenger car- ried is usually a reporter who writes his impressions aiter he gets back to the office. As a rule he sleeps through the flight and sees nothing, wherefore it is delightful to the pilot to read “the majes- tic Susquehanna lav beneath us,” when he knows very well the reporter never saw it, unless in a dream. News-reel photographers and cameramen are tre- quent passengers on advertising flights, as are the commercial mapping and photo- eraph men, to whom a flight is just part of the day’s work. It is the passenger who, has never before been up, but who vants all the stunts, who causes amuse- ment to pilots. I once carried a real-estate man who decided to open his new subdivision by looping over it and dropping a key from the air. This key was a massive wooden one, about four feet long, .and gilded ‘a golden kev from the ‘clouds,’ he called it in his ad. Whoever reached the kev first, when it fell, was to get a lot. We started off, the little man clutching his big key. In one of the loops he let it go, to hang on. It blew back, struck | a glancing but painful blow on the hea and disappeared. “Well,” | thought, “t! subdivision is open anyhow.” But whe we landed at our home field, there the key wedged firmly in the tail-u: bracing. Lately much publicity has been give supposed cures of deafness by diving airplanes. Probably some of the suffere: imagined they were helped; perhaps some even were. However, I have never met anyone who claims to have derived a: benefit from diving in an airplane, thous [ have read of them in newspapers. | one case, it is true, the patient never cor plained again of deafness—the plane very old one, broke up in the dive! A the shocks of air travel do not come the pilot. Sometimes the passenger get a decided thrill, as did Richard Barthe mess, the movie actor, last spring. T! plane in which he had flown as a pa senger from Virginia landed at Bolli: Field, Washington, and stopped in t! middle of the aerodrome. Barthelme looked back to see why his pilot did n taxi into the hangar. The pilot was sit ting slumped down in his seat. He ha died of heart failure! Hardly a day passes but some new c ht to an aviation field for livery a few hundred miles away at a hut dred miles an hour. It may be a cor gressman rushing to keep a speaking e1 gagement, repair parts for a broken chine, an animal for a circus, or, as \laska last year, a ca of precious serum need to save the children stricken town. In Eur they transport gold by plane to foil bandits zo is broug The Author and a Friend Pose for a “Smuggler” Picture | J

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POPULAR MECHANICS 561 POLICE DOG FAILS AS DETECTIVE TESTS IN GERMANY SHOW fas the value of the police dog as a ctive for trailing suspects and finding ing persons and objects been overes- ited? Reports of tests conducted in rmany indicate that it has, although nion is divided in that country and the s have stanch defenders. The question e with the publication of conclusions ‘hed by Maj. Most, former manager large training school for the dogs. declared that they could not be ned so that they would generally rec- ze the scent of a strange person after ng smelled of the person or his be- sings, and that it was almost impos- e for them to pick up a cold scent. ese statements were challenged by a ce inspector. A test was promptly ranged to determine the point. In the ence of numerous officials, six dogs in active police service, after twenty- en trials, succeeded only twice in the ts, which consisted in picking up a cold ent, recognizing a fresh one, finding an ticle by the scent of its owner, and icking down a man and finding him ter having smelled his belongings. They und only one article and one man. Lat- er, sixteen dogs went through the tests with no better results. JACK RAISES AUTO BY GAS AT TURN OF WRIST Kneeling, with the attendant likelihood soiling the clothing, and having to nipulate a ratchet or. lever are elimi nated in an automobile jack that lifts cars the expansion of a tube of compressed is released within a cylinder. The gas container is placed in the end of the jack ndle. A turn of the wrist, on a grip, pierces the bulb hat contains. the ipor, allowing it ’ pass to the cyl- inder fitted within n air-tight jacket. ubes enough for i year’s use are ontained ina agazine under he removable top of the cylinder, nd there is a ireaded top which is screwed upward to it snugly under the car before applying the gas. By turning another grip on the andle, the jack is lowered. It can be topped at any moment. Ready for an Ascent in Jumping Balloon; Propeller Is Attached Just below the Support Cords JUMPING PROPELLER BALLOON HELPS TRAIN AVIATORS Equipped with a propeller, a jumping balloon devised by two Ohio airmen, pet mits a single passenger to rise quickly to various altitudes from a few hundred to several thousand feet for taking picture learning to control and guide the craft and making parachute landings. The balloon is slightly elongated, offering less resist ance to the air, and because it can rise so quickly, it is adapted to jumping over buildings, trees and other obstacles. By changing the position of the propeller blades and the direction of their rotation, the height to which the balloon ascends can be governed. @In one vear, a sea urchin lays as many eggs as there are inhabitants in New York city, it is estimated.

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How Giant Ocean Liners Defeat — THE REGULAR PERIOD OF A 600-FOOT LINER IN A GALE EQUALS || SECONDS HEAVY WEATHER _SEC ONDs — me ~ TWO HUGE WAVES EACH 450 . AT THIS MOMENT (5 LESS THE ARCHITECT | FETY NEARLY DOUBLE [HIS ey BUOYANCY uP ‘oor ioht Copyri Giant 900-Foot Liners Are Subject to Strains Approximating 2,000,000 Foot-Tons as They Ride the Crests of Ocean Waves, Yet Are So Stanch They Resist the Terrific Bending Pressure

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t Jnited Forces of Wind and Water ——

x at FOOT LINER REGULARLY PITCHES ("9 " . ip. DOWN EVERY 8 SECONDS : THE 7~-— =I ot YET THE MODERN SHIP EA ' ; = lh) TERRIFIC STRAIN Pe *4

” OF A MODERN LINER LIST CAUSED BY WIND PRESSURE =5 DEGREES WIND BLOWING AT GOMILES PER HOUR —_ EXERTING N . A PRESSURE oF OVER 00 TONS

BIG-ROLLS THAT ARE NOT DANGEROUS

Illustrated London News Regularity of a Clock Pendulum, Yet Are Built So They Can't Turn Over

These Sketches Show How Ships Roll from Side to Side and Pitch Up and Down from End to End with the 563

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564 POPULAR THIRTY-FIVE-FOOT “POLICEMAN” SHOWS AUTOISTS SHORT CUT At a street intersection on the outskirts of Topeka, Kans., a huge steel sign rep- resenting a trafhe policeman informs mo- . SHORT 4” THROUG EEP TO if Rion Fig- Putting Finishing Touches on Giant Traffic Sign; ure Is Thirty-Five Feet High torists that they can save a mile by pass- ing through the city in a certain avenue. The guide was erected by an improvement association for the benefit of merchants. It is thirty-five feet high and, being paint- ed in bright colors, is visible from a con- siderable distance. Across the street, rival storekeepers have erected a large ar- row pointing a route to their shops. LOST PERSONS FOUND BY RADIO AS AID TO POLICE Twice daily, from municipal broadcast- ing station WNYC, New York city, radio performs one of its most interesting and helpful services. At 7:30 and 10:30 p.m., an officer of the police bureau of missing persons steps to the microphone and the ether waves carry a description of any person who is lost, the date of disappear- ance and other facts which may help in finding him. Listeners are urged to co- operate with the police in locating the in- dividual wanted. Not long ago, a prayer broadcast by the Rev. Dr. S. Parkes Cad man for the safe return of a boy who had mamawmsTFYryT a MECHANICS run away from home was heard by the fugitive himself, who happened to be working as a bell boy in a hotel. The message, echoing through the lobby in the hotel’s loud speaker, exerted a pow- erful effect on the lad as his own : ime was mentioned and he decided to go bac! A woman, who had not seen her brother for forty years, told her story to official of station WEAO at Ohio State uni versity. In a little town in Arkansas, daughter of the missing man was listen ing in when the plea for his return put on the air. The father clapped o1 headphones and listened in amazement a he heard his name repeated. He rushed to a telegraph office, sent an assu message to his sister and took the n train for the Ohio town in which she | The radio appeals often supplement the newspaper accounts of missing per giving further facts about them. HOLLOW FIBER SCREW PLUG HOLDS IN ANY MATERIAL For attaching all kinds of devic: brick, concrete, marble, and almost other sort of material, a hollow plug inserted in a small hole which is | drilled, forms a gripping foundatio: hold the screw. It is not affected by n ture, absorbs and resists vibrations, will not strip the threads of the s: It is manufactured in more than fifty ferent sizes, and as it becomes almo integral part of the surrounding mat under pressure, it is not likely to be ; out. Only a small hole is necessary first inserting it and it both saves time ‘ . 2) 3 © Es 3 ¥ : po MAR ARAaS A> STANDARD WOOD SCREW B- RAWLPLUG USED WITH ANY Std SIZE WOOD SCREW C- DETAIL SHOWING SCREW ENTERING RAWLPL D- “ TURNED HOME aes ty “ WITHDRAWN, LEAVIN PERFECT THREADS CUT IN RAWLPLI Plug in Hole Grips Screw, and Perfect Thread Cut When Screw Is Taken Out permits a neater and more lasting j fastening shelves, hooks and many lar articles. ar Se ae eae 2 ae es ak ee

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POPULAR t MECHANICS By FLOYD TAYLOR Hy] EAVILY armored automobiles, as sturdy as those used in the World are rolling over Broadway, Fifth enue and Forty-second street carrying ld in New York. Visitors from com- nities where bandits are fewer stare at e steel monsters and wonder why a pon of war is used in the city. he answer to their question is that by using an implement of war have e bankers and jewelers and employers th large payrolls been able to protect ir money and valuables from gunmen save the lives of their messengers. \Mlost of the banks now use armored rs furnished them by one of the several mpanies operating in New York. The 1ards and drivers of the cars are care- ly selected men. One company hires ly American citizens who have spotless ords, who have passed rigid intelli- ence tests and physical examinations, nd who are natural marksmen. They ust be able to shoot from the hip with evolvers and, at short range, to hit their rgets invariably. The conductor rides inside the car ith one guard. Another guard is on the eat with the driver. Each has a revolv- The driver's compartment is partly inclosed by steel and partly by three thicknesses of heavy plate glass, which is bullet-proof. There are loopholes care- fully sheathed so that it is almost impos- sible for a would-be robber to shoot from the outside into the car. Gun racks surround the Some of the cars have machine guns which shoot twenty-one shots a second and all have scatter-shot riot guns. One type of car has a ventilating machine over each loophole to forestall any at- tempt by bandits to use gas. The cars can be stopped by the conductors inside. One company has thirty-four armored automobiles. It brought the first of these cars to New York four years ago and its only loss has been the theft of a small pay- roll by an employe. This company esti mates it now handles an average of $8,- 000,000 a day. Hundreds of large pay rolls are handled by the armored-car com- panies. They take the money from the bank, make up the payrolls in their of fices, carry the envelopes to the firms us- ing the service and, in some instances, pay the employes. They assume all respon- sibility for loss. The average charge for the use of an armored car is about $75 a day. Most of conductor.

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566 POPULAR MECHANICS = —_ —_—— - = — Two Hundred and Fifty Millions in Cash and Securities ray | Moved from One Bank to Another a Bk and a Half Away; Even the Porters Carrying the the work is done on long-term contracts. It consists in handling payrolls, the re- ceipts of stores and other business houses and of theaters, and the routine trans- fer of bank funds. But there are many unusual jobs. Paint- ings and antique furniture often are in- trusted to the companies. One of them oxes Wear Guns at Their Belts moved a museum to a new home and often taken valuable paintings by masters from homes to galleries for hibitions. Wealthy society women New York use the cars to send tl! jewelry to and from safe-deposit vau A $100,000 string of pearls has been only load for one car on several trips fi Two Hundred Mi Dollars in Bonds Securities Were M by This Crew in Afternoon =. * oh - cE See

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POPULAR MECHANICS cr Oo ~ et of Armored Forts Invading Wall Street Move a Bank; Right, New York City’s Funds Are Guarded by Sharpshooters nk to a residence in the neigh- od of Central park. e armored-car companies have own vaults and, late at night, ct receipts from theaters and ity affairs, such as bazaars and nees. They keep the money in the ults until banks open the next morn- But the most outstanding work of armored cars is in moving banks, and e most spectacular of all was the trans- - of $3,000,000,000 in cash and negotiable ‘urities from the old vaults of the Fed- Reserve in the Equitable building to e new home of the bank in Liberty reet. (his moving job was guarded by 150 licemen, fifty detectives, fifteen mem- rs of the police bomb squad, forty bank tectives, sixty secret-service men, and crews of four men carried by each the thirty-seven armored cars which ere used. (he work began, unheralded, one Sat- lay noon. ‘The entire district was eared of those not helping to move the nk. Sharpshooters were perched on oath roofs and ledges. Machine mounted at every corner on the route. Four armored cars were posted at each street intersection with any car engaged in turned off the route. The money and securities were packed ere guns \ Wi eck moving if it orders to the in trunks in the old bank vaults. Each trunk was locked and sealed by bank othcials and the armored-car company gave a receipt for it as its men took it from the vault. All afternoon rubber tires rolled under the steel monsters car rying millions at each load. The hundred trips required were made between noon

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568 and 5:00 p.m. Saturday and 9:00 a.m. and 12:30 p.m. Sunday. Four armored cars were used when $250,000,000 was moved up Broadway last year from the vaults of the Metropolitan Trust company to the Chatham and Phoenix National bank. There were ma- chine guns ready for action on each car and a slightly larger car, known as a “fort,” was placed at Broadway and Lib- erty street, ready for a counteroffensive if bandits tried to raid the money cars. The work took three hours. Bandits face capture or death if they try to rob armored cars moving bank funds. Their chances are little better in attacking cars in their routine work of carrying payrolls. They seem to have given up hope of clutching the gold that rolls through the streets protected by bullet-proof steel and machine guns. The constant shipments of gold to and from New York by ocean liners is an- The Inside and Outside of an Armored Fort on Wheels: the Guard Is Armed with a Machine Gun Which Fires POPULAR MECHANICS other temptation to bandits. The go placed in vaults of steel on the liners is carefully guarded. It is taken to from the piers in armored cars. Some of the shipments are very la The steamship “Mauretania” brou $20,000,000 on one trip last October. G coming to America from Europe is us: ly packed in boxes, about nine in deep, nine inches wide and twenty in Twenty Shots a Second

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POPULAR red Cars Have Fciled Bandit acks on Payrolls and Shipments ld and Silver Bullion between nks and Steamship Docks and each of them just $50,000. hese boxes must be ried in loading and un- ling. The American ks, when shipping gold, it in kegs, which can led. The kegs are of ut ten-gallon size and en filled, weigh approx- itely 180 pounds. In th kegs and boxes ex- tly $50,000 is the unit MECHANICS 569 down gangplanks by laborers as a check- er counts, “$250,000, $300,000, 350, 400, 450, half a million.” The full load for an armored car is from $1,500,000 to $2,500,000. The guards who ride in the cars ‘ause of the necessity of ilitating counting. Thus, twenty kegs ld a million. (he United States Assay office handles business of American and foreign nks shipping gold. Gold to be shipped road as bullion is taken to the office and ere melted and molded into bricks. The iid is tested for fineness. Gold received \merican bankers is tested at the office fore it is delivered. Sometimes gold is transferred without eing remelted. J. P. Morgan & Co. ce received a shipment from France of ricks which had been sent to that country eventeen years before in connection with e building of the Panama canal. A few { the bricks had been tested for the fine- ess of the gold; the rest had not been suched. Gold is taken from the ships at their locks in the Hudson river to the assay thee in armored cars. The kegs are rolled say that any gunman who thinks it would be easy to steal that gold is welcome to try. BROWN EYES OUTLAST BLUE BY EXCLUDING LIGHT Other factors being equal, brown eyes are less liable to give trouble than blue, according to a western specialist, for the dark irises act as curtains, shutting out light and thus protecting the nerves and inner structures. Blue eyes, he declares, are more often the exception to the rule that a normal eye will not need glasse until the person is forty-five years old. Special illuminating devices and gauges enable oculists to examine patients much more accurately than was possible simply by testing the vision with printed cards They have instruments which also permit inspection of the interior of the eye for traces of disease or approaching cataracts.

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570 POPULAR MECHANICS RAILWAY CARS DISINFECTED IN GAS TANKS After railroad cars have traveled 80,000 miles or so over a German line, they are taken to the repair shops where all up- holstery is removed and they are given a thorough fumiga- tion in a huge air- tight metal tank. A special kind of gas, deadly to all sorts of insects and dis- ease germs, is used, the vapor being ad- mitted to the tank after the receptacle has been tightly closed with the car inside. The gas tL Mie Upper Photo Shows End of Fumigating Compartment Being Closed After Car Is Inside; View of Interior Discloses Gas Pipes, and, at Right, Car About to Be Disinfected Halted at Entrance penetrates small cracks and fissures that could not be reached by ordinary spray- ing, and is left turned on long enough to rid the cars of all germs. PLASTER THAT ABSORBS SOUND AIDS SICK AND RADIO To meet the demand for a wall cover- ing that will decrease unnecessary noise, “the curse of modern hospital construc- tion,” Dr. Paul Sabine and associates at Riverbank laboratories have developed a sound-absorbing plaster, which, tests have shown, is from eight to ten times as effec- tive as the ordinary article. It is of spongy appearance, the thousands of little chambers in its surface acting as “mutf- flers” for sound instead of reflecting it, as -happens in the case of a smooth wall. Experiments have shown that tile with a hard plaster coating is a better reflector of sound than a glass mirror is of light. A good mirror throws back only ab ninety per cent of the illumination 1 strikes it, while hard plaster reflects proximately ninety-seven per cent of sound that reaches it, thus giving rise t confusion of echoes and_ vibratio; Sounds of ordinary intensity in suc] room, must unde go some 450 refi tions before th« are absorbed t such an extent to beinaudib|l: This takes about 48 seconds. Ca pets help “deade: the noises, as the absorb about twe: ty-five per cent Copyright, Henry Miller the sound that strikes them, but their u in hospitals is unsanitary. The new plaste: has also proved effective as covering i the walls of radio-broadcasting studi as it produces about the same results textile drapes, but does not make t! room so “dead” as to discourage « frighten performers, who sometimes bre down before the microphone when the do not hear the customary resonance their own voices. Hotels also have fou that the plaster is efficient in sleepi: rooms where street or interior noises a1 likely to disturb guests. When the pla ter was first prepared, it was covered wit an ordinary calcimine coating. To t! dismay of the scientists, it was discevere that this substance had destroyed t! sound-absorbing qualities of the materia for the minute pores had been filled u They then experimented until they fou a preparation which would not stop tl! openings. It can be dyed to any color ar coats the plaster so thoroughly that may be washed with a damp rag withou damage. To demonstrate the materi tavo rooms have been constructed at Ri

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POPULAR ink. They are of identical dimensions, being coated with ordinary plaster the other with the special mixture. re is no audible echo in the latter m, but talking in an ordinary voice le in the other, produces a confusion sunds, and the click of a typewriter mes sufficiently annoying to disturb ne trying to concentrate. JTO TRUNK HOLDS TENT, BED AND CHAIRS FOR CAMPING imping equipment for two or four ms is carried in a trunk that fits on rear of the automobile. The box ls a tent, poles, with flooring and cov- ¢ included, a bed, mattress, two tables, benches, back rest and clothes ham- k, and is but thirteen by twenty-one orty-six inches in size. The smaller t for two weighs only twenty-eight nds, the larger, thirty-two. A feature the tent is that it requires no stakes or s, being held by spring-steel rods that inside the brass poles.. It has win- s of transparent material and is water- f, and the flooring may be snapped place at the height of the bed to keep dirt and insects. The benches and les are formed from the trunk itself. ‘equipment was designed by an experi- ed camper and is said to have proved irable and practical after extensive tests. MECHANICS 571 Piaying Automatic Concertina and View of Roll PLAYER CONCERTINA REQUIRES LITTLE SKILL Mastery of the concertina is considered difficult, but anyone, even without musical knowledge, it is said, can play an auto- matic instrument now on the market. Ex- ternally, it closely resembles an ordinary concertina, but its keys are merely placed on for form, the music being produced by a “plaver” roll con- cealed in a chamber on one side. Drawing and shutting the bellows and squeezing an attachment on the right side oper- ates the mechanism. The tones produced are said to resemble those of the familiar instrument very closely. ELECTRICITY CAN BE WEIGHED It is now possible to talk of electricity in terms of weight as if it were tea or sugar, according to Prof. John Ambrose Fleming, a British expert in wireless telegraphy. He has estimated that in a year, the type of incan- descent lamp commonly used for household pur- poses in England, would ent, Tables and Benches Shown Here Are All Carried in the Trunk on the Rear of the Automobile consume about an ounce of electricity.

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BUILDS AIR-PRESSURE CABINET TO AID HIS HEARING Unwilling to pay $50 for each trip in an airplane to take dives for helping his hear- ing, a California man has built a cabinet Builder in Air Cabinet; Valve Regulates Pressure, Af- fording Practically Same Effects as Trip in Plane in which the air pressure can be regulated at will from that at sea level to that at 12,000 feet above. Simply by sitting in the chamber and turning a valve, he re- ceives practically the same effect as would have been obtained from the airplane ride. Doctors and aviators have found that the air-pressure treatment for the hard of hearing, usually is only temporary in its results and benefits only certain kinds of deafness. It is of aid chiefly when the difhculty is due to a dislocation of the eardrum, which may be forced too far in or too far out. Changes in air pressure cause the membrane to assume a normal position in some cases, and then hearing is improved, but in the great majority of the drum tends to back to its original place in a short time. cases or ZO BIG RAINS AT MUSCLE SHOALS AID POWER DEVELOPMENT Nature has favored man’s power-plant enterprise at Muscle Shoals not only with a steep descent in the Tennessee river, 126 feet in thirty-two miles, but with an abun- dant rainfall, so that the water supply is adequate even in the so-called dry season. The average annual precipitation over the area is more than fifty-two inches, about fourteen inches in each of the winter, spring and summer seasons and ten in the POPULAR MECHANICS autumn, making it one of the best wat interior regions in the United States. shoals occupy the district between Dy tur and Florence, Ala. Wilson dam. erected just above Florence, with a he t of 102 feet, is capable of producing 624,(0 horsepower. The barricade has formed pool which extends upstream fifteen mil and backs up the river water fifty-f miles above Decatur. RAISING DOGS FOR THE WORLD IS BIG BRITISH INDUSTRY It is estimated that the dog industry Great Britain, directly and indirectly, pro vides employment for approximately 150.- 000 persons, and that the value of the pets on hand and in shipment is nearly $10 000,000. Every day, dogs are shipped to foreign ports. In one week, not long ago two Pekingese were sent to Kashmit pack of twelve foxhounds to Bagdad thirty-two harriers to Berlin; whippets to Australia; a sheep dog to Paris and set ters to Patagonia. The United State: the best customer, and Indian princes ar second. An American buyer recently pu: chased a British-bred terrier for near! $5,000, and a chow commanded aln twice that sum. Special kennels are c structed for the dogs to meet the dema: of the journeys. Warmly lined weather-tight containers, with a system ventilators arranged to provide a sup] of fresh air no matter where the ken: is placed, are built for shipments to | rador and other cold regions, while d: going to the tropics need kennels wit open fronts and sun blinds. POURING SPOUT FOR TUMBLERS AIDS IN FILLING BOTTLES Liquids can be poured from tum- blers into nar- row-necked bottles or other receptacles with- out spilling by fit- ting a small wire spout to the rim of the glass. It guides the con- tents in a small stream away from the side of the holder, directing it accurately. The attachment can be | on or taken off in a second and fits edg of different thickness.

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POPULAR MECHANICS vernment Topographical Engineers at Work at the Crest of a Colorado River Rapids on the Maps Used in Planning the Vast Reclamation Scheme and Electric Power Development Taming the Grand Canyon’s Torrent The Colorado, Navigated But Three Times, to Be Harnessed for Power, Irrigation and Flood Control T® ANSFORMATION of the landscape in seven western states is involved in ewly launched government project for ntrolling the Colorado river—the most ficult stream in the United States. The inges will include the creation of thir- en lakes, with an area of more than XX) square miles, and with a linear length se to 900 miles. These bodies of water ll lie between Green river, Utah, and irker, Arizona. Of chief interest to the everyday citi- en is the evolution proposed for the (:rand Canyon. For more than 200 miles hrough this giant chasm, the Colorado a stream of death-dealing violence. uccessful passage of the treacherous hannel has been achieved but three times n history. Pioneer journeys were made n 1869 and 1871 by Maj. John W. Powell, he first to accomplish the dangerous voyage. Since his trips, the sole expedi- tion to pass through in safety was that of the United States geological survey in making the explorations for the present plan of development. Adventurous ex- plorers had attempted the passage at vari- ous times during the last fifty years, but had never returned. The death toll has been extensive. The project includes the creation of lakes within the canyon, with resultant ease of access for tourists and sight seers. With these lakes brought into be ing, the voyager will be able to traverse the full length of the gorge. Motorboat and comfortable travel will replace the perils of the present condition. In the transformed canyon, the general public will be able to explore the marvels of the chasm with none of the danger now ren dering such trips prohibitive. The creation of lakes within the canyon area will come as a by-product of one o! the greatest engineering enterprises ever undertaken. In the 250 miles of the pre ent danger zone, there will be eight dams forming an almost continuous flight of steps in a descent of 2,500 feet and backing the water of the river into a lakes from fifteen to 180 miles long. In point of size, the largest dam i that at Glen Canyon, toward the eastern series ol edge of the Grand Canyon area. Thi structure is planned on gigantic lines, with a sheer height of 386 feet, and with underground foundations extending seventy-seven feet to bedrock. To build the foundation will involve the pouring of 10,000 cubic yards of concrete each

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574 POPULAR MECHANICS The extent of the scenic changes is colossal, but this is of minor importance in comparison with the economic and enginee: ing problems to be solved by the great undertaking. That the lakes should carry tourists to places now inaccessible is purel, incidental. The primary pu poses are flood control, irriga tion and the development of elec trical power. The forces of the Colorado are enormous. As a flood menace the river is regarded ; the most dangerous i the United States, a circumstance produce: by conflicting elements in nature. Southeast ern California sees the conflict at its worst. I: this portion of it course, the river flows along a channel several hundred feet higher than the lower-than sea-level environment of the Salton sea. The sole protection to the low-lying area is in the silty banks of the stream, which have long defied protective efforts on the part ol engineers. Between the unsub stantial banks, the river has a way of rais ing itself to new level! through the deposit ot One of the Boats That Made the Canyon Trip, Above; Surveying a Side Canyon, Center, and the Muddy Flood Waves, Below working day during the season of low water. The lake created by the Glen Canyon dam will extend for a distance of 180 miles upstream. Other dams scheduled in the Grand Canyon re- gion include: Redwall, 222 feet high and with thirty-five-mile lake; Mineral Canyon, 345 feet high, with forty-six- mile lake; Ruby Canyon, 286 feet high, with twen- tv-five-mile lake; Specter Chasm, 223 feet high, with twenty-four-mile lake; Havasu, 209 feet high, with twenty-three- mile lake, and Devil's sand and silt brought Slide, 163 feet high, with ; down from its moun nineteen-mile lake. Be- p22 2 tain channel. There are tween Havasu and , ~ — times when the deposit Devil’s Slide will come Bridge Canyon dam with sheer height of 566 feet, equivalent to a building of more than forty stor- ies. The lake created by it will be seventy-seven miles long. The dams within the Grand Can- yon area constitute but a part of the mighty structures contem- plated in the government plan. In the upper reaches of the river, the project calls for a dam 512 feet in height, located at Dark Canyon, Utah, establishing a lake 150 miles in length. Below Devil's Slide there are four dams, creating lakes ranging up to 100 miles.

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— 4 POPULAR MECHANICS 575 e of the Dam and Power-House Sites, Showing How a Lake 209 Feet above the Present Water Level Will Be Impounded by a Wall across the Narrow Limestone Canyon the bottom of the river to the point nger, and causes the stream to eat its through the banks with resultant lation of the country below. In the recent flood of this character, the ge amounted to millions of dollars, it was two years before engineers eeded in repairing the breaks and re- ng the stream to its normal channel ing to the Gulf of California. The - of recurring floods is ever present, lis is one of the primary require- ts for control of the Colorado ugh engineering skill. lood control is contemplated through agency of the vast dams and lakes ved. The lakes will act as reservoirs storing surplus water in times of high permitting gradual discharge at a that will involve no flood peril. Thi itself, offers good reason for the at- pt to control the river. /f similar importance is the irrigation ure of the project. The river rises 14,000-foot mountains and flows for miles through desert country where ile soil awaits but the magic gift of ter. The storage reservoirs are nned to furnish water as needed to areas within reach of irrigation hes, giving crop production of some- ng like $400,000,000 a year, and reclaim- waste land of a potential value of hun- ds of millions. The acreage involved 6,000,000. In such portion of this area now possesses irrigation facilities, the eT tl esent condition does not supply the ter that is needed. Existing regulation ‘thods fail to overcome the dry-vear rtage. Through the construction of thirteen new dams, treating the river a whole, there will come constant im- sunding of the water at times of greatest flow, and discharge will be regulated by local requirements. In the production of electrical energy the storage plan has an importance in no way secondary to its function in the mat- ter of irrigation. Engineers figure that without the lake-reservoir storage facili ties, it will be impossible to develop more than one-third of the potential energy of the Colorado. The proposed dams will provide more than 5,000,000 horsepower and allow the same waters to be used for reclamation purposes. It is not in the Grand Canyon alone that the artificial lakes will provide new accessibility for scenic wonders of the west. Another notable instance will be in the case of the Rainbow Natural sridge, now out of reach except by well- organized pack travel. Under the in fluence of the Glen Canyon dam, the river will form a lake extending to a point within one mile of this natural wonder bringing the bridge within easy reach of tourists and sight-seers Rainbow Natural Bridge is the world’s chief treasure of its kind. For size and symmetry of proportions, this sandstone arch surpasses all other natural bridges in existence. With a span of 208 feet and a height of 309 feet, this arch has a spread that would accommodate the dome of the United States capitol, with room to spare. Engineers state that the transforma tion of the Grand Canyon will be chiefly a matter of accessibility. The lakes will be deep enough for boats, but without ap preciable impairment of the vast depth of the canyon itself. No scenic damage is involved in the proposed undertaking. The project is the result of twenty vears of exploration and study.

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576 POPULAR MECHANICS AIR RIFLE SHOOTS FLAT BULLET TO KILL SMALL ANIMALS Shooting a specially shaped flat lead bul- . let of .22 caliber, a high-power air rifle that Air Rifle, at Right, and Its Bullets Com- pared with .22-Caliber eo Shells pierces half an inch of wood at a distance of ten feet or kill rats and other little ani- mals at close range, has been developed for target practice and small game. It is not a toy, yet it is not classed as a fire- arm under the law, for the bullets are made as blunt as possible on the front end, as light as their diameter permits and hollow at the base, so that the air will reduce their speed. This is just the re- verse of the pattern of bullets intended for killing. The air rifle’s pellets fall to the ground before they have gone a dis- tance of half a city block. The gun is about the size and shape of an ordinary repeating rifle. The stock is used as a lever to pump up air pressure in the tube, which occupies about the same position as the magazine in a real rifle. Bullets are inserted by opening a bolt similar to that of the military weapon. RADIO PROGRAM IS PRESERVED FOR FUTURE ON STEEL BAND Tune in and listen later. This is the possibility a recent radio invention by two Viennese experts holds for the fan who may want to enjoy a program days or months after it is broadcast. Concerts are recorded on magnetized steel bands somewhat like motion-picture films. They are drawn through the electromagne( of the earphone so as to be magnetized in accordance with the impulses from the re- ceiver and before the headphone magnet turns the vibrations into sounds. ‘The band may then be run through another electromagnet, resulting in the production of the tones as they would have been heard at the time of the broadcasting With this arrangement, selections may be sent through the radio transmitter directly from the steel band, thereby insuring the best performance, as repeated records may be made to get an errorless perform- ance, and the bands may be demagnetized and used to record other programs. HOW INSECTS CHANGE GARB SHOWN IN EXHIBIT Remarkable changes which various kinds of insects undergo during their life cycles are portrayed in a special exhibit the University of Illinois. The displa solves what sometimes seems to be a m tery to the lav mind, the evident disa; pearance of injurious bugs or worm Usually, the creatures have not gone away, but have simply taken on a new di guise as part of their regular development For instance, some varieties pass throug! four stages, the egg, larva, pupa and fina! the adult. Butterflies, moths, beetles, flix ants and wasps pass through this cyc! which is known as a complex metamor phosis. Grasshoppers and chinchbugs | eggs that produce creatures which, except for the absence of wings, have all the « ternal structures of the adult. FIND USE FOR OLD LIGHT BULBS AS FIRE EXTINGUISHERS Like the aba doned razor blad the old electri light bulb is nuisance in ma! families, but German engine: has discovered way to make th: useful. He fi the burned -: lights with chemical, se the opening and obtains an _ effect “bomb,” which, hurled into a_ bla quickly reduces the flames as the gl: bursts and liberates the chemical.

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tesy The Sphere f the Great Celestial Mysteries Potsdam Astronomers Are Studying, a Spiral Nebula; Part of Mechanism That Moves Dome and Side View of Huge Refracting Telescope NDER three great domes of an elab is carefully studied. One of the impor itely equipped observatory at Pots tant aids to this research is a huge con Germany, scientists are at work vex lens so adjusted that it collects the every night when the heavens are illumination from stars, too slight to b trying to solve the riddles of the seen by the unaided eve, focuses it down Many of the important astronomi to a clear little point, which is then split liscoveries of recent vears have been up by means of a special prism into some e here. The institution was founded of the colors of the rainbow his band 1874 for the purpose of investigating of colored light is photographed and the phvsical structure of ‘the sun and result studied under a microscope The With a huge telescope and other colors give the scientists a clue as to the uments, the observers not only seek elements the stars contain. One oft the heavenly bodies, but trv to find out huge domes is turned on a series of hat substances thev are made. Fixed twenty trucks, each with three rollers a are catalogued according to theit vard in diameter All the domes are ro rhtness and the light of variable ones tated on their vertical axis.

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578 POPULAR MECHANICS In Case of Dispute over . a” exneri oe . Ownership of Umbrella the ™onths’ experiments. According to Young Woman’s Photo- of the scientists responsible for its dis graph ba Em in Iden- ery, the serum would have saved t! sands of lives had it been used during World War, and he believes that it wi! of great benefit to athletes or others fering skin abrasions or wounds in w! the tetanus germs may find entran the system. BOTTLE CARS FOR HELIUM GAS AID AIR SERVICE To supply army and navy dirigibles \ helium gas from the production plant Texas, a special type of railway car been constructed. It consists of t! large bottle-shaped cylinders with a c bined capacity of 201,000 cubic feet of which is forced into the containers u1 a pressure of 2,000 pounds to the squ inch at a temperature of seventy deg: Fahrenheit. Each cylinder is thirty feet three inches long, and the outsid . ameter is four feet seven inches. _ walls, of high-grade steel, are two inc : thick, and the endpieces around the val are held with high-strength nickel-st studs. Six of these special helium cars carry enough gas to inflate airships OWNER’S PHOTO ON UMBRELLA large as the “Los Angeles.” The we TO PREVENT LOSS of the entire car is approximately 20 pounds, but only about 2,000 pounds this is represented by the. helium. tanks have a volume of about 507 cu feet. The cars are easily routed to various airdromes about the country, simplify the work of the balloon cr: who had to manage containers of differ: shapes and sizes and did not know ex SERUM TO COMBAT LOCKJAW ly how much gas was being shipped u: HAS LASTING EFFECT it was relea Complete and durable immunization against lockjaw is held out as a possibility from a serum which has been developed at the Pasteur institute in Paris. It is said to con- tain microbe secretions that not only kill the germs of the disease, but also protect the subject by tortifying his system against them in case he should suffer a scratch or wound liable to expose him to lockjaw. Both horses and men are re- ported to have been treated successtully with this serum, which was prepared after six Special Tank Car for Carrying Helium Gas to Dirigibles To protect her umbrella, an eastern young woman has placed her photograph on the outside, so that identification will be simple in case of loss or theft. It does not interfere with closing the shade, is securely fastened and affords a novelty.

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What Makes a Radio Tube Good? Selection for the Particular Task of Each Socket, and Proper Care \ HY some radio tubes are better than ’ others and why some tubes work n one socket, but upset the operation the entire set when shifted to another, two of the first mysteries confronting owner of a receiving set. The ex- nation may lie in any one of a dozen rs which influence the operation of tube. Or it may go back to the mak- of the tube at the factory, for it is tually impossible to produce these deli- te electrical valves to exact specifica- Some are bound to be better than rs, though the others are not neces- bad, provided all tubes used in the ire fairly well balanced as to capacity. luch of the rk in mak- tubes is ne by auto- tic machin- to reduce e chances of uman error, even the st machinery nnot get round the light differ- ences in the ectrical char- icteristics of ‘ferent pieces of wire. There are hree general nds of tubes n use for re- ‘elving sets, those taking ix volts, three and one nd one - half Its of A-bat- tery current to light the fila- ment. The six- volt tubes are he large ones used with stor- ige batteries for most home sets. The maller were leveloped Primarily volts and Control Necessary to Get the Best Results cause they can be operated from dry bat- teries. None of the latter are as efficient, nor do they last as long, as the six-volt size, so that their use is seldom recom mended, except where lightness and port- ability are desired, or where, for other reasons, it is not practical to use a storage battery. All of the tubes are alike in the main features of their construction, having three elements, the filament, which is lighted by the A-battery, and a plate and grid. In operation, the tubes act as valves, in fact they are known abroad as valves. The heated filament gives off streams of electrons which bombard the surround ing plate. Be » tween the fila ment and plate, however, is a fine network of wires, forming the grid, and corresponding to the valve gate or shutter When the grid has a negative electrical charge, the electrons from the filament are repelled, failing to reach the plate. As the grid poten- tial changes to positive, the electrons pass throughto complete the circuit. The opening and closing of this electrical shut- ter proceeds at avery high rate, the high er the better, up to a certain point, when os- cillation sets in, and, in a regen- erative receiv- er, the oscillat _ . ing tube be or portable re- ceivers, be- Six Stages in the Making ot a Radio Tube, Starting with the Plate and Grid and on through the Assembly of the Parts comes a minia ture broadcast ;

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580 POPULAR MECHANICS battery connections or wires within t set should never be made without fir removing the tubes, to prevent their b ing blown out by short circuits. After r pairs or changes have been made, a sin tube can be pli iced in each socket in tu for test, and if it lights safely, the ot! may then be installed. In this way more than one tube will be lost if the: is anything wrong with the wiring. The life of a tube depends upon t! time during a the filament will co: tinue to give off electrons, but this n be extended ~ rejuvenating the tul provided it is a 201-A or 199. The v and-a-half tubes cannot be revived. Sin 1922, most of the tubes manufactur have had filaments composed of tungst: treated with thorium, because the latt: material has an exceptionally high d charge of electrons. After some mont! use, the number electrons will d: but more thoriu can be broug! to the surface putting the tub. in a rejuvenat: which subjects t filament to a hig er voltage for a fe seconds, and the: to its standar power for a quart: of an hour or so For a set used fai: ly regularly, reju venation two o three times a ve is not too much. The Electric Welder Which Fixes the Joints as the Tube’s Insides Are Assembled; Adding the Outer Bulb, Cen- ter; and, Below, Pump- ing Out the Air and Sealing the Tube ing set and begins to annoy all the neigh- bors by creating howls and whistles in their receivers. Oscillation may be controlled by the use of a potentiom- eter, which gives a delicate control of the grid potential and enables it to be balanced up to the highest point at which the tube will op- erate, and then held there. Tubes work best on the ragged edge of oscillation, where a slight shift would send them over the border. The potentiometer en- ables the tuner to reach this point of ad- justment as accurately as the vernier con- trol on the tuning dials provides better tuning. Tubes are as delicate as the old-time tungsten lamps in their early days, and, like those early lights, should only be operated in a vertical position. Otherwise the heated filament, expanding as its tem- perature rises, is apt to sag and touch the grid wires, causing a short circuit within the tube. Slight shocks often break the wire members, and for this reason spring’ or sponge-rubber base sockets, or strips of sponge rubber under plain sockets, prove safest. Changes in Sele ag?) 7 ts a. Ye

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POPULAR MECHANICS 581 e new-model tubes differ consider- from those which have been in use the earliest days of broadcasting. have longer prongs, and the fila- prongs differ in size from those for and plate. The new sockets are having four holes into which the rs are thrust, and the difference in makes it impossible to put in the tube ny but the right way. The pin on side of the tube, which locks in the of the old-style sockets, is retained, hat new tubes can be used in the ets of existing sets. iny of the new sets are being built fewer rheostats, using fixed resist- as ballast in the amplifying stages, egulate the filament current, passing necessary amount for the tube. Where stats are used, the 201-A tubes, con- ing .25 ampere, should have twenty irty-five ohms’ resistance in the rheo- The 199-tubes, with a current con-, ption of .06 pere, can he same e, while The Base Is Add- ed Last; Center, Seasoning the Fil aments by Cook- ing Out the Thorium; Below, ~ UV-200 the Final Test d the C-300, th so-called gether take it’ detector \ three ohms. es, take six- i 13 JH ye 4 Pires wee >” j Power tubes, "I . — which are now coming into general use, af- ford higher am- plification without distor- tion of the re- ception. hey are used in the final stage ot rheostats. hen three or ore 199 or \ tubes are rved by one heostat, the -sistance eeded is only ohms, and or six of he tubes to- the set. They do not actual- ly amplify any more than the other tubes, but are so constructed that they can pass a greater volume of sound without dis- torting it. One of the mysteries to many radio users has been the silverlike mirror which lines the glass bulbs of all but the soft detector tubes. It has nothing to do with the operation of the tube, nor does its gradual disappearance, particularly above the plate, indicate that the tube is near- ing the end of its life. The film is mere- ly an accident attendant to a novel meth- od adopted to obtain an unusually high vacuum in a short time when the tube is pumped out, a method which has made possible the thoriated-tungsten filaments at a reasonable price. All the early tubes employed either e

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582 POPULAR MECHANICS

plain tungsten or carbon filaments. Tung all evenly balanced, is better than one \ sten gives a bright white light, as in seven tubes above the average and Mazda lamps, and the carbon filaments poor one. Practically every deale: a dull-red glow, as in the old-fashioned equipped with a tube tester, and the bu carbon electric light. Hence one kind of | should himself check the testing and tube became known as a dull emitter and the tubes which come nearest to a & the other as a bright emitter. eral average. In the search for a better filament ma- If this precaution is observed terial, the discovery that thorium would buying the tubes; if they are not for throw off large quantities of electrons by turning up the rheostats farther was made, but it likewise was found that necessary; if they are rejuvenated « minute quantities of gases released from sionally as needed, and if ordinary cat the surfaces of the plate and grid, after observed in handling them on the ox the tube was pumped out, had a bad effect sions when they must be removed on the operation of the composition fila their sockets, modern radio tubes shi ment. To get around it by pumping out last for from one to two years, or | the tube to a higher vacuum would have with average use of the set. meant hours of pumping on each tube, They have been made as nearl\ slowing up production and more than proof as is humanly possible, but doubling the retail price of tubes. tubes remain one of the most delicate The difheulty was solved, however, by entific instruments ever developed for attaching a tiny piece of magnesium pa by the layman, and should be tre per, ordinary flashlight material, to the accordingly. plate before the tube was assembled. The —— air is then pumped out, and when the SOLVING MYSTERIES OF PLANT tube is nearly exhausted an electrical coil TO AID HUMAN BEINGS slipped around the tube. The metal of the plate, in the center of the magnetic In an interesting laboratory in Eng] field of the coil, becomes heated through plants are being subjected to a wide the electrical action, and touches off the riety of tests, while scientists study tl tiny flashlight, the explosion blowing out growth and how they respond to vari the last of the gases. The result, how- lights and different kinds of food, t ever, is a silverlike film on the glass tube, plant products may be raised more « the film being the particles of magnesium ciently and, incidentally, that more n from the flash. be learned of the functions of the hur he early thoriated-tungsten tubes were body, for life in plants and in animal good for not more than 200 hours’ service, similar in some respects. <A _ geraniu but with the new method of construction, with a curved stem is given an elect the average tube is good for at least 1000 shock and made to grow in a differ hours, and many will serve faithfully for direction; certain plants that require |i twice that period. for normal growth are placed in darkne In selecting tubes for a multi-tube re- while others that could do well with lit ceiver, they should be carefully balanced. illumination are subjected to baths fr \n eight-tube receiver with all tubes reg- colored arc lamps. To discover how p istering a capacity below the average, but feed, the experimenters starve them. Courtesy the DeForest Laborat The Grandfather of All Tubes, Dr. Lee DeForest’s First Audion Tube, Invented in 1906, on the Left, and Five of His Latest Models Alongside; the Radio Tube Is Just Twenty Years Old

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POPULAR EK “VILLAINS” OF PLANT LIFE TO CURB DISEASES loping to save millions of dollars now every year in trees and de- ed by disease, scientists at the Boyce institute for crops mpson MECHANICS 583 MOTORBOAT AS CYCLE SIDECAR IS EASILY DETACHED kor campers and sportsmen, a motor- cycle equipped with a motorboat sidecar, solves the question of hauling the craft

t research are seek- the cause of various ents that afflict veg- les, corn, peaches other products. An nsive study is being of the so-called diseases, the “yel- and “mosaics” ch annually destroy es of crops. While origin of these has vet been discovered, e investigators say it may be found in e form of bacteria so ll as to be invisible en under the micro- pe, or it may be a us or disturbance in physiology of the nt itself. One “villain”

lower life already has en identified. It is a ticular kind of leaf pper that causes “aster ow.” Although it is known to spread e disease from plant to plant, just what pread and how are mysteries. Tests ve shown that no other kind of hopper insect is capable of infecting othe s. The leaves of the beet curl, cran develop. false potato ives roll, tobacco mottles deep and light reen, peach and aster leaves yellow and rivel, and all these maladies seem to be lated in some way just as human dis ises, vellow fever and malaria are trans itted by the bite of the mosquito. The <perimenters have found that when oung plants develop one of the diseases hey may die, but lder ones merely producing rt rries blossoms, inguish,

Motorboat Serves as

proper anale Use When Riders Cycle and Is Ready for Sidecar for Reach Lakes or Streams to and from lakes and streams, and per mits enjovment of a greater variety oft pleasures with but little added trouble lhe boat can be quickly taken off or at tached, and where roads are available, the outfit travelers of the task of portages when cruising waters sections. passable relieves navigable onlv in LEVER PEN FOR WRITING SIGNS REQUIRES LITTLE SKILL Even novices are said to be able to let- ter signs attractively and neatly with a special pen now on the market. It is used like a pencil, has a lever on the side for filling the ink cham

maller leaves, blos- =" ber, and its point con ~~" - -_z ° ( < rrui Oo sists r ot oms and ft uit. IZ SA4ASO (BE ists of a number Vlants grown from small teeth so ad tubers and cuttings, justed that both uch as potatoes and light and heavy lines ugar cane, may are easily made and struggle from year shading is done al to year and the dis most automaticalls ease tends to become lore severe. It is disastrous to erennials than to lore

Various sizes of points and a special kind of ink are pro iis vided with the let- Samples of Work It Skill Is Needed S.gn-Lettering Pen and : : annuals. Imost No tering outfit.

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584 SAILBOAT BUILT ON TRICYCLE TRAVELS LAND OR WATER Tricycle Yacht Constructed by a Dutch Workman Who Rode It from Holland to Paris Mounted on a tricycle, a yacht con- structed by a Dutch workman, “sails” both on land and water and recently car- ried its owner from Holland to Paris. Foot power is utilized for propulsion when the outfit is in the water in addition to the sail, and as the hull clears the ground, it is easy to ride on the street. POPULAR MECHANICS HARD COAL IN PENNSYLVANIA ENOUGH TO LAST CENTURY Pennsylvania deposits contain sufficic hard coal to last 110 years, according a report prepared by the forest and wate department of that state. It is estimat that there are 16,354,676,000 tons of thracite in the ground and that more th half of this is recoverable. The origi: content of the field is believed to ha been more than 20,000,000,000 long to: Improved mining methods are reduci: the amount of coal lost each year. the early days only lump anthracite shipped, the smaller sizes being left in t! mines or carted to the dumps. Duri: the past five years, even fine silt has bee reclaimed and burned under boilers forced draft. Much coal must be left the mines in the form of pillars to su; port the shafts, and in other places t! proximity of streams prevents diggin as seepage would flood the passages. ASSEMBLING DINOSAUR’S BONES WILL REQUIRE TWO YEARS Scientists who are piecing together t! skeleton of a huge dinosaur, found abou three years ago in northeastern Utah, fa a two years’ task before the restoratio: will be ready for display in the Washing ton museum. Missing parts must modeled in material that will fit in wit the real bones, and the whole skeleto is being constructed to correspond exactly as possible to that of the ori inal animal. Fitting Together Bones of Huge Dinosaur for Museum Display; Missing Pieces Must Be Molded, and Incom plete or Broken Ones Reconstructed, So That Finished Work Will Be Accurate

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POPULAR MECHANICS bs or '? 8) or Shattering Tile-and-Concrete Floors on Top of Doomed Building under Blows of 500-Pound Weight Dropped from Top of Breaker Arm; Wreckage Falls into Trucks on Floor Below Experts Are Required to Demolish Big Buildings to Make Room for Growing Cities By PAUL \ BIG tractor stops abruptly at a chute, - the body tips, and two tons of brok- bricks roar down into a river barge. ponderous concrete breaker drops a ()-pound weight, and a section of tile oring crashes. Five caterpillar trucks, me loaded with brick and others drag- ing steel beams, clank their way through confusion of timbers. A compressed- ‘gun chatters, and a concrete wall built or eternity, tumbles into a dusty heap. Such a scene might be duplicated al- most anywhere, but this particular one is being enacted nine stories above a Chi- ago street on top of a huge warehouse, fireproof structure built of steel, brick nd concrete. Although only a few years ld, it has been doomed to destruction to lake way for a driveway. The task of undoing what took the builders many months, had to be done in sixty days. A penalty of $1,500 a day was imposed for overtime. But the wrecking experts did it with ample time to spare, demonstrat- ing what skill and modern equipment can .ccomplish when structural processes are reversed and the object is destruction. There are more tricks to the trade of wrecking than the layman suspects, the foreman of this job declared. His com- PADDOCK pany has been destroving buildings at the rate of more than $4,000,000 a vear to make room for city growth. Wrecking is almost as old as building itself, but modern steel construction has created new problems. The feat of carting away the remains of a big building through con- gested traffic is, in itself, a mighty task In fact, the foreman declared, getting rid of the rubbish is the first big trick of the business. Before actual work starts, a skilled es timator visits the building and sizes up its salvage value. He must know markets and materials, have a keen eye for the worth of such equipment as _ elevator mechanism, boilers and plumbing. His company often acts as a merchant, buy- ing a big building for its wrecking value and selling what comes out of it. Mil lions of dollars’ worth of junk is scrapped from doomed buildings. Sometimes al most priceless materials are to be found in old mansions where magnificent wood work was lavished unsparingly in their interior. The estimator must be an au thority, to some extent, on art. On his report, the company either contracts to take the job with the salvage or agrees to do only the wrecking. The decision

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586 POPULAR Swift Hopper Tractors Dump Debris Directly into iron sold Trucks Below, Speeding the Work on Big Jobs iT ‘ aN). The contract specitie often means the difference between a profit and loss. The first step in destroying a building is to take out the windows. Plumbing may follow while workers begin to strip the roof. Wreckers consider the roof of most buildings equivalent to two stories, for fewer men can work upon it, there is greater risk, and its destruction is more difficult. As the job progresses, it is evi- dent that the popular conception of a wrecker as only a stalwart laborer, pro- ficient with the pick and crowbar, is wrong. He must be able to scale high walls, stand on an eight-inch ledge and calmly disiodge the bricks beneath his feet without falling. Often he must climb to perilous positions to burn out rivets with acetylene torches. Hazards of fall- ing walls surround him, for strains and stresses cannot be accurately measured in old buildings, and there is always the chance that nature’s own wrecking crew, rust and decay, already have started the job, increasing its dangers. He cannot destroy carelessly, as materials with sal- vage value must be handled cautiously. One of the most dificult feats in the history of wrecking, th® experts say, was accomplished in tearing down an old Chi- cago steel building that had a conical roof, 180 feet from the ground, over an open court. One by one, the curved steel girders were removed until only two, op- posite each other, remained. To _ pre- vent accidents, derricks were erected:on each side of the building and tackle fas- Chutes to Barges or MECHANICS tened around each sup port at a point beyo: the center, so that t! beams would hot tip under the weight of man. Then two skill wreckers climbe up to the ends of the supports, one on eat girder. Working cau tiously, they cut away the last remaining riy ets so that the two beams swung free at exactly the same time and the men rode the: to the ground without mishap. Even big pieces oi steel must be handled carefully when the have salvage value. [1 the case of the big Chi cago warehouse, th for $80,000 that the lengths must be delivered in goo: condition, unsprung and not mutilated To save time in handling, and to protect the pieces, a chute was constructed from the top of the building to the bottom. It was made of beams taken from the floor and, at two places in the descent, othe beams were placed as wedges to chec! the speed of the girders, and they shot like projectiles down the runway, send ing out showers of sparks and crashing against a special bulwark at the bottom When the steel was coming from the higher floors, this bulwark was built up of twelve-by-twelve-inch wooden pieces Some of the heavier lengths plunged through the backstop like bullets. Steel bulwarks were later used. The beams were picked up by a steam shovel, minus the bucket, and swung into a truck which hauled them away. Columns with roug! edges or protruding sides, likely to stick in the chute, were lowered with derricks The chute not only saved time, but avoid ed the necessity of hiring structural iron workers at high wages. The concrete breaker, used for the first time on a job of this kind, shattered the floor directly into the hoppers of the trac- tors below, when possible, to save extra shoveling. Bits of wooden flooring and other inflammable rubbish were dropped down the smokestack and consumed in the pits below. The fire helped warm the workers as well as solved the rubbish disposal problem. sonfires were built next to concrete walls in places to soiten ae Pe) BE lag S 2 SupAT Cee. wT

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POPULAR MECHANICS 587 Pulling the Portable Office to a Lower Floor and “Logging” Steel Beams with Caterpillar Tractor to the Chutes Where They Are Sent Crashing Down to Ground Level and Hauled Away

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588 them for the wreckers. Four compressed- air guns operating at eighty and 100 pounds’ pressure were employed in de- molishing the walls. The compressors and other equipment were taken to the upper floors in the building’s freight elevators. Some pieces had to be knocked down and were reassembled. Moving from floor to floor was accomplished by means of a ramp. \ portable office, electrically lighted and with telephones, was head- quarters for the timekeeper and foreman on each floor. As the wrecking neared the ground, the office was pulled to the next floor by ropes, and put into service again after reconnecting the wiring. Materials taken from doomed _ build- ings serve many purposes. Steel goes to the mills for resmelting, altering buildings or for shoring in new construction work, depending upon the condition of the beams; junkmen purchase plumbing, ma- chinery, boilers and fixtures; some of the plate glass will reappear as automobile windshields; lead, brass, zinc and other metals are melted up and perhaps used for ammunition or for manufacturing va- rious articles. Lumber that has been only slightly damaged, is kept for scaffolding, shoring and timbering, or for erecting cheap houses. Wrecking a big building usually brings joy to many poor families, for there are almost always loads of kin- dling wood to be had free. Broken plaster, :. brick and _ concrete “> f ‘SS S s? =) POPULAR MECHANICS are saved for filling or for road building Stone slabs are often worth preservin: Tombstones are carved from granite ar marble blocks, while other stoneworl that escapes damage may be used in mau soleums or apartment houses. Partly because of the difficulties of the work and the consequent need of greate skill, wages of professional wreckers in most cities have increased within the last few years from a few cents an hour to more than one dollar. New York city’ some 300 professional wreckers now com- mand $1.05 an hour, whereas their pay be fore the World War was less than fift cents. Only a few of the workers seen on a job are classed as real wrecker They are the men who mount walls wit! bar or pick and do the most: hazardous parts of the task. In the eyes of most insurance com panies, wrecking, like building, is a ha; ardous occupation. Some surety cerns charge the contractors more for protection in the event of death or injury of the wrecker than for any other class of labor. In some cases, it amounts to halt a dollar for every dollar paid the men in wages. The likelihood of injury with the consequent loss of time, rather than thi great probability of fatalities, explains this. Comparatively few deaths occur. con Connecting Hose to a “Gun”’ for ene cing | Down Walls with Compressed Air; Bricks and Concrete Meant to Stand for Decades rumbles under This Modern Form of Attack

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POPULAR MECHANICS 589 Wreckers’ Batter Down the Old to Make Way for the New General View of Wrecking Scene from Top of Building Near By

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590 ADHESIVE AUTO-TRAFFIC SIGNS LAST LONG ON PAVEMENT To replace hand-painted automobile- trathe signs tor pavements, letters on a POPULAR MECHANICS a certain class of hydrocarbons which are found in huge quantities in every petro leum refinery. To get rid of these sub- stances, the industry is now wasting ap proximately 90,000,000 gallons of moto: fuel annually, destroying the stuff from which sy: thetic rubber could be prepared. During the war, Germany produced rubber from the b products of alcohol dis- tillation, but these mate rials are no longer ava able at economical prices, and one of the reason the synthetic rubber in dustry has not develope in this country, is that there has not been sufi cient investment in the necessary experiment laboratories for the study of petroleun Scientists point out th although this count produces about 2,000,000 barrels of crude oil eve: day, nobody yet know the chemical constituent of the oil and nobod Putting Traffic-Sign Letters on Pavement; They Are on Glued Cloth Squares Which Become Firmly Attached to Surface in Short Time special kind of durable cotton cloth that is coated on one side with an adhesive are quickly laid and are said to last much longer than ordinary signs. Automobiles running over them and the action of the sun’s rays both help to bind the cloth to the pavement. The letters are uniform in size and are shipped with the adhesive sides together, so that they are ready for use simply by pulling them apart. They will stick to cement, brick, cobblestones, macadam, asphalt, wood-block or any hard surface, about the only precaution necessary being to thoroughly clean the surface and have it absolutely dry. Tests have shown that while hand-painted let- ters will last only four or five weeks, the cloth signs withstood traffic four or five months. The experiment was made at the same intersection. SOURCE OF SYNTHETIC RUBBER SEEN IN OIL WASTE In the gummy substance that develops from the oil and clogs automobile valves, scientists see a source of synthetic rubber that. can be produced cheaply and in large quantities. The product can be made from knows what gasoline although about thirt per cent of all the oi! produced is converted into this forn Since synthetic’ silk and alcohol alread have been developed through scientific research, and better glass and indigo ar: now being made, success is predicted al for artificial rubber making. CORK PULLER WITH FLAT HOOK PREVENTS TEARING Corks are re moved without tearing them bh means of a pull with a flat hook at the end. The ex tractor is inserte at one side be tween the bottl and the cork, an a twist places t! hook where it « fit under the bot tom of the cor! Then a slow steady pull wil remove the stopper, usually with very little difficulty. nr

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POPULAR MECHANICS 591 BRITISH PLANE-CARRIER SHIP HAS HUGE FLYING DECK Wide space for airplanes to land and take off, as well as commodious hangars re provided in the plane-carrier ship furious,’ recently added to the British ivy. To assist the aviators, the center f the flying deck is plainly marked in road white lines so that it can be more easily seen from the air and to prevent iccidents. Entrance to the stern hangar wide enough to permit handling large units. Guns are also set here. The ship las all facilities of a land hangar. STORM-PROOF TELEPHONE LINE TO LINK MID-WEST CITIES Telephone service between large cities in the middle west will be less hampered, after severe ice and sleet storms, as a re sult of a special line now cable being Two Views of the British Airplane Carrier “Furious” It Is a Seagoing Hangar and Land- ing Field Com- bined, with Broad Upper Deck, Shops and Wide Entrance at Stern Guarded by Guns; in Upper Photo, End of Center Line That Divides Flying Deck Is Seen in Front of Pilot's Cabin between Chicago and St It will connect with a similar s\ tem already built to New York. ual wires are sheathed in a protective metal coating, and the cable is strung be tween poles somewhat shorter than the usual telephone supports and set closet together. At intervals of fifty-five miles “repeater stations,” to $300.000 each constructed Louis. Individ costing from $150,000 are erected to preserve the volume of the voice, insuring sati actory service. Vacuum tubes, similar to hose used in radio are important unit in these stations, building up the sound so that there is little loss. It is estimated that the Chicago-St. Louis line will repre sent an investment of nearly $7,000,000 when completed. As an example of hovw a storm will cripple telephone service, the wind and ice of December 18-19, 1924, did $1,000,000 damage to the lines ot company alone, felling 23,000 poles and putting thousands of wires out of use. ; i ? t -1 neariy one

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592 TRIAL SHOTS AT DUMMY MAN IMPROVE POLICEMEN’S AIM Boston policemen are being trained to cope with bandits by target practice at a liie-size silhouette of a man marked to Computing the Score of Pistol Fire after Shots at Dummy Target; Figure Is Life-Size and Marked in “Vulnerable” show vulnerable spots and to provide a means for keeping an accurate score of the shots. The target shows the figure as though drawing a revolver from a hip pocket. One of the objectives of the drill is to see if the marksmen can hit certain parts of the figure at will. MILLIONS OF THUNDERSTORMS RECORDED EACH YEAR Better than 45,000 thunderstorms each day, or 1,800 an hour, is the record for the entire surface of the earth, accord- ing to recent computations based on years of observation at thousands of widely scattered stations. The island of Java is accorded the place of the world’s most thundery spot, with no less than 223 storm days each year, while in vast tracts around the poles, a thunderstorm every ten years is an event. The almost rainless Sahara desert and the interior of Australia share this honor with the top and bottom of the earth. Twenty-year records of the United States weather bureau show that there are few spots in this country where the person afraid of lightning may be rea- Sections POPULAR MECHANICS sonably safe from scares throughout the year. Part of the coast region of Califor nia, part of the Alaskan coast and a few other sections, however, are fairly free from such disturbances. ; The month-by-month charts of thun derstorms for the twenty year period indicate that the storm areas have cer tain definite focal centers and follow certain paths as the seasons change. During the months of De- cember, January and Feb- ruary the center of thun derstorm activity is around Vicksburg, Miss but by February there is a tendency to drift south eastward, with a ary center developing ove: Pensacola, Fla. In Marc! the center of activity i still the lower Mississippi valley, with the area spreading northeast over the Tennessee Ohio river valleys. In April, Shreveport, La., is the main center, but the area has spread over most of the northeastern states, as well as west and north. In May, the primary cen- ter develops over Tampa, Fla., with a strong secondary over the lower plains states, great activity prevailing over thie entire east, except in the Canadian border states and New England. In June the area spreads northward and covers all of the states east of the while in the following month the activity in the Rockies increases, with a strong secondary center Sante Fe, N. M. The latter weakens in August, while the Tampa and Sante Fe second storm and Rockies, over centers persist into September, and in October the first shifts south to Key West and the second east toward the plains states. During November the storm area retreats to the winter center. In foreign lands, central Africa rates next to Java in thunderstorm frequency, with 150 days a year; southern Mexico has 142; Panama 136; central Brazil 105, and Madagascar ninety-five. Ocean cur- rents, prevailing winds, and mountain ranges have a marked effect on the num ber of storms. The cold current sweep ing up the coast of Chile keeps the coun try free from storms, while the warm Gulf stream sweeps a long trail of gales and storms across the North Atlantic.

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POPULAR MECHANICS 593 a Reserences 4 Us Copyright, S. W. Clatworthy Drawing Shows How Thunderstorms Are Distributed over the Globe; the References in the Upper-Left Corner Indicate the Frequency, in Number of Days, as Shown by Lines on the Globe

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594 HOME TRAINER FOR GOLFERS SHOWS STROKE ERRORS With a compact home-training outfit, golfers not only receive valuable practice Golf Ball Is Attached to Cord Connected with Indi- cators, Which Register Errors in Stroke for the course, but learn just what is wrong with their strokes, whether they top or slice the ball, and the distance the sphere would have gone in actual play is also registered. The instrument is a platform arrangement, little more than two feet long, about nine inches wide and two and one-half inches high. At one end, a golf ball is attached to a cord which is anchored to the board and the indicating mechanism. This consists of a distance gauge to show the force of the stroke, a register that tells if the ball deviates from a straight line and two in- dicators which mark, with telltale ar- rows, if the sphere is topped, sliced or both. After a stroke, the indi- cators are instantly set back to a neutral position simply by step- ping upon the button to which the ball is attached. The train- er can be used indoors or out. PENCIL SPOT WEIGHED BY BALANCE SCALE Among the marvelous in- struments used by scien- tists is a balance scale so delicately adjusted that it will tip under the weight of the few particles of lead deposited upon a piece of POPULAR MECHANICS be srectee era thst a |S Ms * Lit +> ©, Teal, articles that are nevér associated \ weight at all except in scientific exp: ments. Another device, which has a p: tical service for thousands of persons called a spherometer, a gauge that reg ters variations as slight as one-hundr: thousandth part of an inch in the cur ture of lenses for spectacles. If t housewife had a cutting machine lik: that used in examining blood corpusc!l she could prepare a sandwich ten fi long and eight feet wide from a piece cheese only an inch in each direction, it shaves extremely thin slices and c cut a blood corpuscle into three part The thickness of these parings, of ha or of cigaret papers can be measured desired, in another gauge which fegiste: differences as small as one-two-hundred thousandth part of an inch. Time measuring instruments are now so exact that after a journey around the wor! the mariner can detect variations of n more than a second a week and som: times less. With a cup micromete: changing positions in seams of coal similar formations that move only an inch in 100 years, can be forecast. HOUSE BUILT WITHOUT NAILS HELD BY WOODEN SCREWS Held together entirely by woode: screws instead of nails, a large frame house of elaborate pattern is one of thx sights of Atlantic City. It is the Micl gan State house, built for the Philadelphi centennial fifty vears ago, and was move to its present location after the fair. D. spite its age, it has not been remodel and is in an excellent state of preservation. ape iking a perioc aper in maki 1 with a pencil. It weighs in It; Fifty Years Old, but Still Substantial, Although There Is Not a Single Nail Frame House Held Together with Wooden Screws

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we G MASHING and grinding its way along a narrow lane of water, fissured in he ice floes, creeps a steamship whose gging is covered with frost and icicles. lhe trailing smoke from its stack and the blunt-nosed hull are sharply outlined igainst the fields of blinding white. For lays, the steamship has been nosing its ay into the frozen North. Somewhere n these vast ice floes are hidden the great erds of “harps” (seals). The “scunner” lookout man) has been vainly seeking these animals ever since the ship crept through the broken ice in St. John’s har- bor and headed into the Atlantic. “White coats to stabburd,” shouts the ookout as he hears a wailing which be- tokens that somewhere near lies a “patch” if seals, perhaps 50,000 in number, and, rving for their mothers, the white-coat iby seals, the special object of the teamers quest. Krom the deck soars a small airplane hich is soon lost to view. Forty minutes pass, and then the ship hears the hum- ming of the returning craft. ° The pilot innounces that he has spotted a patch of harps, 80,000 strong, on the ice about live miles away. The captain shouts and the engine- room telegraph rings to go astern. A lane has to be opened through the ice en- compassing the ship. “Astern it is!” Round = spins the wheel, and the three helmsmen hold on to the spokes, since, if the rudder hits POPULAR MECHANICS 595 By HAROLD T. WILKINS an ice pan and wrenches the wheel out of their hands, the whirling spokes will easily break their arms. The steamer backs to gather way for a charge on the floes. The telegraph rings full speed ahead, and the iron-sheathed bow drives crashing onto the floes. The ice, however, is too thick to be battered, and the bombers fix blasting charges and fuses to long poles, and drive holes through the ice by the side of the ship. A red-hot iron bar is touched to the end of the fuses, and the bomb is caught up and thrust far under the ice. Blocks of ice shoot up as high as the masthead, and the way is once more clear for the ship. Half an hour later, the scunner in the crow’s nest sights a herd of thousands of seals lying asleep on the ice. Men swarm down ladders and ropes from t] decks onto the ice with gaffs, “sculping” knives and rifles. Behind each gunnet walks an assistant with a bag of ammu nition. Some carry torches, others bread in case they lose sight of the ship in the mist. hey crawl over an ice _ field which heaves and falls as though it were the deck of a ship rocked by a heavy swell. Then the sharpshooters take up position behind hummocks. A shot rings out, and an old sentinel seal falls. The firing becomes general and there is a panic-stricken rush of the herd to the “bobbing holes,” in which they shelter and rear their young below the suriace

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596 of the floes. If the bobbing holes have frozen over, the seals race to a weak spot on the ice which their combined weight crushes, letting them through to deep water and safety. Next, men with sheath knives in their belts and armed with six-foot-long gaffs attack the small seals. Out come the knives, and the fat or blubber of the young white coats is cut off. It is rolled over, its pelt skillfully and neatly re- moved, and its “flippers,“ or fore paws, cut off to be later turned into an appetiz ing dish. The pelts, or “sculps,” are piled Sealers Stowing the Pelts in the Hold after a Successful Hunt on the Ice Floes off Newfound- land, and, Insert, the Puppy- like Face of an Infant White- Coat Seal, the Chief Rrize of the Hunt; They Are Too Young to Show Fear as the Hunters Approach POPULAR MECHANICS up in a pan, and each pan of skin buoyed with a red flag in the daytime a torch at night. Many miles of the floes are covered by the sealers aft jumping off from their ship. A tor light pan may be too far from the for its load to be hauled back, and steamer will have to force a labori passage through the ice to reach the p and collect the sculps. The men who carry the ammunit bags cut off the tails of the seals to t up the kill. Then they tie the pelts t line, and tow them over the icy trail

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POPULAR MECHANICS 597 Sealing Steamers in the Ice Fields with lLookouts on the Yards; Right, Mother als and Their Pups at the Pribilof Islands ird the ship, taking ire not to damage the kins, since any tears ssen their value. On oard the ship, the inches are hauling the ulps and fat on deck rom the ice below. The blubber is run into steam- g tanks, and the sculps are towed in the hold. Now the ins of pelts and fat are safelv n the hold and the tanks. Sparks,” from the radio cabin, has lashed to the land station in code the le of the kill for the benefit of the wait- along on the polar current flowing sout] ng owners and the relatives and friends ward to the Grand Banks At anv mo t the captain and crew. Once more, it ment, an arctic blizzard may cut him off full speed ahead. from his ship. When the barometer is Che Newfoundland sealer, it is obvious. low or falling, the man who gets out of lust be able to endure his months of sight and is caught by the fog creeping irdship. Once on the floes, the sealer, up over the floes, may easily freeze to t peril of his life, must never forget death. 1 P ° - . cor , . - ° lat the ice is ever on the move, drifted The ship is always on the watch for

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598 POPULAR fog, and, at the first sign, the siren shrieks and a flag is run up to the truck to warn the men on the ice. Torches are lit on deck and a light burns on the masthead when the sealers are delayed or lost on the ice fields. Indeed, all night long, whatever the weather, lights burn in the cabin and forecastle, since, at any mo- ment, gales may spring up and the ship be pinched in a jam of ice blocks. One steamer, caught between two enormous pans of ice, had its bottom cut out, and when the ice opened up it sank, the crew being rescued by other steamers of the sealing fleet. Another wooden steamer was nipped amidships and so_ badly squeezed that its rigging became quite slack. As soon as the pressure was eased, the ship resumed its former shape and girth. A few years back, seventy-seven sealers perished in a blizzard on the ice not very far from their ship, which they were utterly unable to reach in the blind- ing storm. Again, an ice hummock may shift under a man as he jumps across the floes and fling him into the icy water. Snow blindness is not uncommon, and goggles have to be worn to shield the eyes from the glare. Bursting boilers are another ever-pres- ent danger. Twenty men were instantly killed when the S.S. “Tigress’” boilers blew up. The terrific strain of forcing a way through the ice may open the ship’s seams or burst its steam pipes; or the cargo may shift under the sudden impact of a hurricane, as in the case of a loaded Newfoundland steamer which went down with 173 men and a full load of seals. Added to these risks, propellers may be Dragging the Sculps, or Seal Pelts, over the Ice to the Sealing Steamer; the Skinning Is Done on the Floating Floes So Each Man Can Take Back a Large Number of Pelts MECHANICS carried away by the ice or the ru smashed, leaving the vessel helpless After all these hardships and dan; have been passed comes the divisio: the spoils when the steamship return port. The owner takes two-thirds of catch, and the crew share the remai: one third. The earnings of a membe: the crew seem to average $60 for weeks’ work; in a bumper year, he : get as much as $150 for the season. record remuneration of a sealing-steat captain in Newfoundland, for twent days’ work, is $5,433, but this amount exceptional. “A man will go for sea! they say, “where gold’ won't draw him.” Seal oil, today, brings about $500 a to: and seal sculps about $4 each. Iron-clad ships break their w through the ice better than wooden ve sels, and at the beginning of the Eur: pean war, Newfoundland possessed powerful fleet of iron steamers. All them, however, were sold, and, at the m ment, all the island’s ships engaged the sealing industry are wooden boat Last year, eight of these wooden stea: ships landed something like 130,000 se in Newfoundland. On shore .at St. John’s, the blubber the seals is run into tanks and refine in steam vats. It is finally bleached the sun and converted into a pure, swe« colorless oil which is used as a safe i luminant in mines, an ingredient in oliv: oil soap, a lubricating oil, in margarin and in perfumes.- The sculps are steepe in brine, and sent to England where the are made into high-grade leather used the manufacture of dainty handbags Pictures by courtesy of the High Commissioner for Newfoundlar 1 &

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POPULAR MECHANICS 599 Strict laws vern the in- istry, and seals an be taken only between March 16 and \pril 16, by steamers which are allowed to make one trip only. Moreover, eals may not be killed on a Sun- day. The New- bureau of fish- eries takes a census of the fur seals on the St. George and St. Paul islands in the Bering sea. Last vear, there were 723,050 seals, compared with 132,000 in the year 1910 when the United States took over : ; ae Seal Rookery; Below, Crew Leaving Ship with Clubs, and ah cS toundland seal Flag-Tipped Lances to Mark the Kill control. 4 he is a hair seal, pelts of the quite distinct from the fur seal of the Alaskan fur seals are cured by steeping Pribilof islands. Its home is in the Arc- tic circle, though it spends only three months of the year there and is migrating the rest of the time. The seals move outh in a great arc after the breeding season, fattening on candlefish as they go. Some of them wander as far south as California, over 1,200 miles away, to re- turn to the rookeries for the next pupping eason. Not only adults but the imma- ture animals too do this. The only place here the fur-seal herd ever comes ashore is on the Pribilof islands. Uncle Sam’s seals on these islands torm about ninety per cent of the world’s iur seals. The management of these herds is entirely in the hands of the gov- ernment, a monopoly made necessary to prevent their extinction. Every year, the in brine, after which they are packed in barrels and shipped to the States, where they are sold at public auction. POLICE WEAR ROLLER SKATES TO COVER LONGER BEATS Roller skates and the Versailles treaty seem to have no connection but they have. The agreement, among many other pro- visions, limited the number of men on German police forces. To enable the re- duced corps to cover their territory pa- trolmen in Dresden are being taught how to use rubber-tired roller skates. An ex- pert has been hired to instruct them and classes are held twice a week. Target practice while skating has also been at- tempted during the lessons.

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600 POPULAR MECHANICS Instead of Being Sent to the Scrap Heap, Old X-Ray Plates Were Fashioned into Serviceable Roof for Hot- ouse; Inspecting Them Gives Workers Diversion from Toil OLD X-RAY PLATES FOR ROOF COVER GREENHOUSE Prisoners working in the greenhouse at the penitentiary on Deer Island, Bos- ton, Mass., if so disposed, can study in- teresting revelations of the human anat- omy simply by glancing upward at the roof, for the covering is composed of discarded X-ray plates donated ‘by the city hospital of Boston. Skulls, arms, ribs, hands and fractured bones are in- cluded in the unusual canopy. SOLID-RUBBER TIRE TRIMMER SAVES TIME AND EXPENSE Solid-rubber tires can be trued up in about five minutes each and at a cost oi not more than fifty cents, it is said, with a simple frame-and-shaft apparatus now on the market. It has a self- centering set of which quickly adjust the wheel to the cor- rect center after it is slipped on the shaft, and a turn of a handle on the other end of the bar revolves the tire so that rough and uneven spots can be quick- ly trimmed off with cones edge. This arrangement makes possib| the use of solid tires until they are prac tically worn out. PUEBLO BUILT BY INDIANS HAD TWO THOUSAND ROOMS While modern city dweliers have been boasting about their mammoth hotel and apartment houses, scientists have been digging among some old ruins in New Mexico and have discovered that an ancient Indian pueblo, near Taos, con tained from 1,500 to 2,000 rooms and probably housed 2,500 persons. This gi gantic building was a whole city in it self and was probably the largest settle ment in North America when Columbus landed. According to Dr \lfred Vincent Kidder, oi Harvard university, who has spent ten years in archae ological research in thi region, the city of Peco was founded about 890 A D. Convenient] constructed on thi edge of a cliff, it was protected fro: attack, and inhabi tants could thro their rubbis! household ings and implements sweep broke into a cutting tool held against the ‘outer Trimming Up a Solid Rubber Tire in Frame Which Accurately Centers the Wheel In the the cen the ravine. course ol!

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POPULAR MECHANICS es, they piled up one of the biggest bage mounds known to man. Unwit- ely they were giving the scholars a rly accurate record of their doings by ; system of refuse disposal, for the big sund, stratified like a huge layer cake, s the story of their 601 CROSS-COUNTRY ARMY AUTO TRAVELS ROUGH GROUND If you should see a small automobile, without a windshield and equipped with four bucket seats, speeding along the ts, industries, lan- age and customs from e time the city was rst settled until it was andoned 150 years ro. Over 10,000 speci- ens have been recov- ed from the heap and rranged to form a 1,000- ear diary of the Pueblo wellers. The city itself was t structed in the form a square with a large urt or yard in the iddle. The houses were alike, four stories gh, with ground-level ooms for storage of orn and other food- tuffs, and upper rooms or living purposes. The ty was without streets. \n underground council hamber was hollowed ut below the walls of tone and mud, which ere constructed by the women. The men cut and set the roof beams. The women vned the houses. The inhabitants sup- rted themselves by growing corn, beans nd squashes. .They made fine pottery, ised cotton and kept turkeys. It is be- ved that the end of the city came at out the time of the American revolu- onary war. GUM CLEANS TYPEWRITER TYPE WALL PAPER AND GLOVES Dirt and ink are ? removed from pewriter type | v a soft gum | that is warmed | by the hands and | ressed down on he characters. oreign matter is iid to adhere to readily and it in be used re- peatedly. It also erves as art gum for removing marks rom drawings, cleaning wall paper, kid loves, collars and other articles. Motor Horse for the Army Man; Upper Photograph Shows How Szsats Tip Forward for Removal; Tarpaulin Is Only Protection for Driver highway, do not hastily assume that it is a 1926 sports model. It is the latest army cross-country car developed to meet the requirements formerly imposed on the horse or small tractor in transporting army personnel and equipment. Officials declare that it achieves the “motorization of the individual man.” Weighing only 1,150 pounds, equipped with steel fenders both in front and rear and with thirty-by- five-inch tires, it can quickly be verted into a truck simply by removing the two rear seats and substituting a spe cial box, which is intended to hold am- munition or small articles. Tests have showed that it is capable of going over rough ground even when loaded to capac- ity. In addition to other tools, a shovel and an ax are strapped to one side. con- @ According to statistics prepared by Lloyd’s, United States ranked sixth among the world’s shipbuilders last year. Total tonnage now under construction here is 105,000; Great Britain is first with 895,000 tons, Italy second with 309,000, Germany third with 234,000, France fourth with 167,000, and Holland fifth with 108,000 tons.

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He Has a Genius for Germs Dr. William H. Park Sees Time When Science Will Abolish Communicable Ills of Mankind By EARL CHAPIN MAY j \ HE CASUAL PX) observer would hardly pick out Dr. William H. Park as a fight- ing man. He is not quite five and a half feet in height and weighs less than 160 pounds. His eyes twinkle brightly behind spectacles and his face often is wreathed in smiles. But he is a fighter just the same. He fights with and for germs. For thirty-three years he has led the battle against communicable dis- eases in America, because he likes the game and rejoices in the results. He in- troduced us to diphtheria anti-toxin. And he discovered his genius for. germs al- most by accident. It was in 1892, shortly after he had re- turned from a year in European hospitals, that Dr. Park suggested to Dr. T. Mitche Prudden, then of Columbia universit that diphtheria should be diagnosed | germ cultures. Up to that time it w our custom to diagnose communicab throat diseases by sight. A_ physicia: would gaze down an inflamed throat a1 pronounce the disease quinsy, scarlet fever or diphtheria, according to his best judgment. Diphtheria cases were fre quently assigned to the same wards simple tonsilitis cases, with disastrous r¢ sults. Dr. Park changed all that. He introduced the swab, the bacteriologica test and the microscope slide. Tonsilitis and scarlet-fever germs grow in chain like a string of pearls. Diphtheria germ are long and clubbed. There is as muc! difference between them, under the mi croscope, as between cinnamon. sstic!] and blueberries. It is a relatively simple matter to discover a diphtheria case no\ “We know from long years of experi ence,” he declares, “that where smallpo» germs have been consistently combated by the use of vaccine virus, smallpox has School and Hospital Combined; Older Children, with Nurse in Attendance, Are Encouraged to Continue Their Lessons While Getting Well, and Are Given Valuable Knowledge to Help Them Guard Their Health 602

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almost disappeared. But we also know that smallpox is rampant in communities here there is effective opposition to pre- ventive measures against it. The number nd fatality of smallpox cases have in- creased nationally each year for the past hree years, because in many states pre- entive measures have not been adequate- ly enforced. “Where chlorine is used in drinking vater, typhoid fever is a rarity. Once upon a time it was a scourge,” says Dr. Park. “The World War proved that in culation against typhoid largely elimi that disease even when drinking ater is contaminated. The world has been virtually freed from yellow fever by cleaning up the breeding places of fever- carrying mosquitoes. Typhus has been banished from our midst by insistence on cleanliness. Cholera has been eliminated in much the same way. “Diphtheria still causes more deaths among children than any other contagious disease. One of every fifteen American children may be expected to have diph- theria before he reaches the age of ten, although I introduced diphtheria anti- toxin—developed in horses and stored in their serum—to the United States in 1894. But diphtheria will cease to be a national menace if we will adopt preven tive: measures—if we will make use of our knowledge. nates POPULAR MECHANICS 603 Story-Telling Time in Willard Parker Hospital; These Children Breathe through Silver Tubes, Having Suf- fered Throat Strictures as a Result of Diphtheria; a Nurse Keeps Constant Watch of Them “Last spring, at the 11lth meeting of the Medical society of New York state, announcement was made that Drs. George F. and Gladys Dick had perfected a toxin test by which those not natural- ly immune from scarlet fever could be detected and given immunizing treat ment. The Dicks and Dr. A. R. Dochez perfected a scarlet-fever anti-toxin last spring, in the fight against pneumonia, Dr. Llovd G. Felton, of the Harvard medical school, announced the isolation white crystalline substance from anti-pneumonic horse serum, which can be administered without causing serum sickness, and Dr. Banghof of the Health department laboratories is helping him perfect it. We believe this treatment will save one-third of the deaths from acute pneumonia, if used before or soon after the symptoms develop. All of these products are now available’ without charge for general use to the people of New York city. “Measles we have nearly always with us, during infancy at least. Ninety per cent of our children have measles. Spe- cialists are combating measles with se- rum from adults who have been mildly attacked. But in spite of all these applied discoveries by which science fights germs with germs, nearly fifty per cent of our national mortality is caused by com municable diseases due directly to germs. of a

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604 “Virtually no children will be attacked by diphtheria if they are given diphtheria toxin-anti-toxin while they are well. And virtually all those attacked will suffer no serious consequences if they are treated with anti-toxin in the early stages of the We have proved that in New York, especially since we have been using 9° qaisease. the Schick test and the immunizing in- jections among our public-school chil- dren. Every parent should be familiar with the Schick test. “Dr. Bela Schick, formerly of Vienna but now of New York city, discovered, in 1913, that if a very small dose of diph- theria toxin is injected into the skin at the wrist, a red spot, about the size of a dime, will appear in a day or so on the tested one’s skin—unless he is naturally immune from diphtheria. If he is natu- rally immune there will be no red spot. This test, known as the ‘Schick test,’ limits the injections of toxin-anti-toxin to those who are not immune. Experi- ence proves that injections of toxin-anti- toxin give protection in a great measure for seven years. “Through study of thousands of cases we learned that while most city babies are born immune because their mothers are immune, and only fifteen per cent of babies under three months are liable to diphtheria, this percentage increases to thirty per cent at six months, and rises to sixty per cent between one and three years and then decreases to twenty per cent at ten years, and to twelve per cent at twenty years and older. So we decided on a primary campaign for eradication of diphtheria in America among children one to three years old, with a secondary one for children from three to ten. “We began our secondary campaign first in the public schools of New York POPULAR MECHANICS city, during 1917. Physicians and their assistants from the city laboratory gav the Schick test to public-school childre: Where the test showed liability to dip! theria, three injections of toxin-anti-toxi: were given. Then the seventy New Yor city baby-health stations began the sec ondary campaign by advising mothers t protect their young children with toxi1 anti-toxin—if the Schick test showed they were not immune—when the reached the age of six months. “The results of these extended cam paigns are shown by statistics. In 1917 there were 1,158 deaths from diphtheria in greater New York. In 1923, in the larger city, there were only 547. Upt date more than 1,000,000 injections toxin-anti-toxin have been given in Ne York city without one serious accident or resultant case of illness. Other citie and towns are following New York’s ex ample, some slowly, some under pressure of local epidemics, and still others more actively than in New York. “Curiously enough, country children are more susceptible to diphtheria thar city children. But in most states diph theria toxin-anti-toxin and diphtheria anti-toxin are distributed without cost t the consumers. Within ten years diph theria may be as rare as smallpox is where vaccination is generally practiced. “Ignorance, carelessness and apathy are responsible for most of the sickness and mortality. When sickness seems remote we are not interested in insurance. When it comes home to us, it may be too late to battle with it. Hence, ignorance carelessness and apathy are our arch en emies. In this fight we must use ou! common sense. We must learn that the body naturally sets up opposition to all bad germs. Youngsters Lined Up for Preventive Inoculation against Diphtheria; One of Every Fifteen American Chil- dren May Be Expected to Have the Disease Before He Is Ten Years Old

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POPULAR MECHANICS 605 Diphtheria Anti-Toxin Saved These Children from Death, but It Was Administered Too Late to Avoid Sickness and Suffering; Timely Preventive Measures Stop the Disease in Its Early Stages “Many years ago I knew a girl who owed symptoms of tuberculosis. Had ie been given only scientific examina- on, she would have been officially listed a prospective consumptive and would ive suffered, mentally at least, from that iact. But her physician, mixing good ense with science, prescribed personal vgiene, open air, much sleep and ample The patient is alive and almost ell today. She does not know she might ive been listed as a ‘lunger’.” Dr. Park led me through a room lined ith bottles containing billions of quin- llions of germs used in combating tuber- ulosis, scarlet fever, pneumonia, typhoid nd diphtheria. He took up one huge ttle, half filled with a reddish liquid, ipon the surface of which was what oked like a cream-colored frosting. “Germs,” he stated, squinting at the bottle. “Aren’t they pretty? Billions of them, each with its mission in life!” I enticed him into a hallway, away from the fascinating germs. I knew that Dr. Park is one of the very few American medical men who have been elected to the French Academy of medicine and that in many other ways he is pre-emi- nent in his branch of the profession. “Where vou and your kind have had a tree hand, you have about eliminated vellow fever, bubonic plague, smallpox, tvphoid fever, tvphus and cholera, from the list of mortal ills,” I suggested. “Isn't it conceivable that some day you may rid ieals. our country of pneumonia, tuberculosis diphtheria, scarlet fever and all other communicable diseases; in other words, that all the bad germs will disappear?” “We can reach such a millennium, I be- lieve,” the germ specialist replied, “but and this is what I am driving at—we cer tainly will not reach it until we use the knowledge science gives us. Let us all learn more about germs and act upon that knowledge.” CORN SUGAR IMPROVES CANDIES AND PRESERVES FLAVORS Although corn sugar is not as sweet the cane product, it isa desirable substitute in the preparation of jams and jellies, ac cording to chemists at the University ot Illinois, as it preserves natural flavors, produces a smooth texture in ice creams and candies, and gives doughnuts and waffles a beautiful brown. The sugar, they say, should not be confused with corn sirup or commercial glucose, which is prepared by treating corn starch with acid and heating it under pressure. Corn sugar is a crystalline product with a high degree of purity, manufactured under methods developed within the last fe years. The processes resemble those used in the making of cane and beet sugars. Besides helping to retain the original flavor of fruits, corn sugar has the same preserving power as cane sugar, the chemists declare.

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G06 PORTABLE WINCH FOR SHOPS HAS VARIABLE SPEEDS To be used either vertically or horizon- tally, a portable winch that does the work of a crane, can be moved by one man and | f Portable Winch Adjusted for Vertical Lift; It Has Variable Speeds for Different Loads is easily set up almost anywhere. For weights below 1,100 and 770 pounds, the speed of lifting can be doubled or trebled respectively. GOING BAREHEADED FAVORED AS REMEDY FOR BALDNESS [If climatic conditions permit, going bareheaded is a step in the right direction to prevent baldness, in the opinion of an eastern physician. It removes one of the contributing causes to loss of hair, a too tight head covering, and also permits the scalp to re- ceive the stimulation of the sun’s rays. It has been estimated that, nor- mally, a person loses about forty hairs each day, but the number is said to be less important than their quality. If one-third or more of the hairs from the combings of three consecutive days are less than six inches long, in the case ofa woman who has not bobbed her hair, it indi- cates that there is a scalp disease needing medical attention. Men, or wo- men with bobs, can de- POPULAR MECHANICS termine the difference in the hairs by e amining the ends. Those that show 1 traces of the scissors should not exce: one-fifth or one-fourth of the total hair of four-inch length lost in three days, t] doctor declares. FOREST FIRE DISCLOSES OIL IN SHALE DEPOSITS Although it destroyed considerable tir ber, a forest fire in the Santa Barbara re serve recently proved a blessing in di guise for it ignited a formation of oil-shale rocks, exposing a deposit that had on! been casually reported by rangers hunters. Columns of dense black smo informed observers that something besid the trees was burning. Examination showed that the fire had spread to the oil rock, and as the loose top shale slipped down the slopes, fresh layers were e» posed so that the fire burned for a con siderable time. believe tl! reservoirs of oil may be found underlying the rock formation. Geologists MODEL PALACE ON WORLD TOUR BUILT IN TWENTY-TWO YEARS What is considered one of the finest examples of model making is a miniature palace constructed by Sir Neville Wilkin son of England. He spent some twenty two years in its making. It represents the royal residence of Titania, queen of thi fairies in “A Midsummer Night’s Dream.’ Elaborate carvings, inlaid: work and tiny decorations are features of the palace which will be shown at the sesquicenten nial exhibition in Philadelphia and will = then go on a tour around the world One of the Rooms of the Model Palace Which Took Twenty-Two Years t Build; It Will Be Taken on World Tour

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POPULAR MECHANICS 607 The Graphic Drawing of Great Britain’s Latest Capital Warship, the “Rodney”; Three Triple Forward Gun Turrets, the Single Center Tower and Tripod Mast Are Distinguishing Features of the Huge Fighter BIG BATTLESHIP FOR BRITAIN sight for it avoided colliding with other CARRIES SINGLE TOWER objects and would reach out with its body to grasp convenient surfaces to help Has the ultimate in battleships been at- its progress. ined? International treaties, limiting en maments, will at least curb numbers of FOLDING GASOLINE CAMP STOVE essels, and some authorities think that e “Rodney,” recently launched in Great HAS TWO-GRATE OVEN sritain, may be the “last of the capital ips as now known, to be built for the iritish navy.” The warship has a dis- lacement of 35,000 tons, carries an ar- iment of nine sixteen-inch guns in three iple turrets placed forward, six six- nch guns in turrets on each side aft, and imerous anti-aircraft weapons. Be- iuse of this arrangement, it has been ossible to group and heavily armor the igazines while the machinery and boil- ers have been installed aft. Instead of ‘ usual tier of bridges, there is but one ‘ntral tower and a tripod mast with itforms for searchlights, and direction nd control stations. Folding stove and. oven are combined in a compact outfit for the auto tourist or camper. It uses gasoline for fuel, has two burners and also two grates in the oven compartment. Legs on each cor- ner swing back against the body when the stove is folded. The oven acts as a protection when not in use, to shield the flames. SINGLE DROP OF WATER HOLDS HUNDRED FORMS OF LIFE Although a drop of water no larger than a buckshot may appear crystal-clear to the unaided eye, it will resemble a small quarium if it is greatly magnified. Study ot a drop from one of the ponds of thie New York zoological gardens showed that it was teeming with as many as 100 torms of life. It was spread upon a glass slide and examined with a high-power microscope. One of the organisms ob- served was a curious animal with an odd- ly formed triangular body with two spin- ning “pinwheels” as means of locomo- tion. It appeared to have the sense of Folding Stove Complete; Fuel Tank in Front

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608 POPULAR SMOKE SOUNDS FIRE ALARM BY SHADOW ON TUBE Photo-electric cells, the extremely sen- ive units that play an important part in sion of pictures by wireless or Sensitive Cell That Sounds Fire Alarm telegraph, have been further adapted to the practical service of silent sentinels, which guard against fires wherever an automatic alarm is needed. They are so delicate that the shadow of a smoke, passing between them and a beam of light directed upon the cells, causes an action that completes an electric circuit and sounds an audible fire call. Another marvelous invention recently exhibited is a ground microphone intended to locate men entombed in mine disasters. It al- ready has been used with great success in finding leaks in gas mains, and is so delicate that the dropping of a pin in its immediate vicinity can be detected, as can almost any sound underground. Wisp ot PRODUCTION OF ARMY SHELLS INCREASED BY NEW METHOD A casual suggestion offered by a reserve officer at a meeting of army ordnance ex- perts, promises to simplify the task of pro- ducing steel tubing for shells up to ten inches in diameter. In case of emergency, it is believed they could be manufactured at the rate of thousands a day without ad- ditional machinery, whereas during the war, single factories were limited to out- puts of 200 or 300 a day, as the pieces had to be first turned to size, pointed on MECHANICS one end and squared off at the other lathes, and then bored out. By the ne process, the shells will be spun from t whirling red-hot tubes whi are now produced commercially for ¢g well use in virtually all sizes required artillery purposes up to ten inches in ameter. “They just cut ’em off like s was the way one officer descril the method, which already has been teste Boring out the squared and pointed en after the spinning to make place for t explosive charge and fuse automatical removes the impurities in the metal, cause the spinning process forces them accumulate in the center. aan seamuess 7cCe ages, REGISTER TO MEASURE NOISE SHOWS QUIETEST PLACES What spot in the city is the noisie How much more racket does a mot truck make than some other vehicle Guesswork in answering these and simi questions is said to be eliminated by noise detector which an eastern invent has devised. By using it on the tops buildings, and other places, and compa ing scores, he has found that in New Yor! city, the noisiest locality is in the vicinit of Sixth avenue and Thirty-fourth street while the quietest is in Greenwich village. Human beings cor tribute very little to the clamor of thx city, while motor trucks are the worst of fenders, the detector indicates. Grove. street Noise Detector in Use on Top of City Building; Soun from the Street Are Registered

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POPULAR [XTY-FOOT MODEL OF OLD CITY BUILT BY GIRLS teresting features of the itv of St. Augustine, Fla., ll as of a large nm Augustine, Fla., the New Old Sections at a Glance; s and Their Director Completing the Sixty-Foot Model lition which is being constructed by ping up sand from the sea, are re- ed in an accurately built model made ost entirely bv girls under the direc- n of an Australian artist. Ten tons of water were needed for representing ocean and Matanzas river, channels depressions being constructed for lding it in such a way that it would not age the miniature streets and build- Yachts, speed boats, the shrimp of St. Augustine and other craft are ) represented in models which are made move in a realistic manner. SLATE AND ASBESTOS CUTTER ALSO PUNCHES HOLES lor greater speed and convenience in ing slate or asbestos shingles, a combi- ion tool now on market is said cut or punch es in either ma- rial without ste and with in edges. It is inipulated some- hat like a pair of ears, powerful everage on the being ap- ied with handle ides MECHANICS Slicing Channels in Slate Shingle with Special Shears; Tool Also Punches Holes, Leaving Clean Edges 609 grips. fitting shingles around irregular parts of The cutter is especially useful in a roof and reduces the number of tools required, besides saving considerable time. LOCOMOTIVE IS JUST A “HOG” TO RAILWAY WORKERS Like many other trades, railroading has developed a slang all its own, rich in vords and phrases that show invention and are expressive of the life the railroad man leads. Among the more familiar terms and their meanings are the follow- ing: “King snipe,” section foreman; “hog,” a “hop toad,” a derail; ator cars: “big hole,” } I the equivalent of a locomotive; “reefers,” refriger- emergency air ap- “master maniac,” master me- “hand-out,” a free meal: “bull fighter,” empty “old man,” superintendent; “pink,” a rush tele- ram; “ham,” ama- plication: chanic; 0 ich " telegrapher; Mal- let-compound loco- “sacred ox,” motive: “shiner,” trainman’s lantern: “blow-in,” arrival; “bear,” the sixteen- hour law.

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POPULAR MECHANICS The Last of the Famous Twenty-Mule Teams of Death Valley Approaching the End of the Final Trip, I November, When Motor Trucks Replaced Them on the Desert Mine Roads Driving the Last Twenty-Mule Team across Death Valley By JACOB ALLRED Last of the drivers of the twenty-mule teams Tae iron mule has driven the flesh- and-blood animal from the desert, nd all us “twenty-mule skinners” are either dead or out of jobs. While we drove we had plenty of adventure, and more work, but science and machinery have beat us and our mules,’and I have just seen the last of the teams sold and the wagons broken up for firewood. With the passing of the twenty-mule teams, however, went one of the most interest ing phases of transportation in America, a method of hauling freight which made possible the opening of the hottest and most dangerous part of the desert. lhe wagons were twenty in number, two to each team of a score of mules. Thev were the largest wagons ever built. Their beds were sixteen feet long, four feet wide and six feet deep, with capacities of 22,500 to 23,000 pounds of ore. Each wagon, empty, weighed near- lv four tons. Since diameter, and the front wheels five fi wide one inch thick. The hubs were at Their tires were eight inches twe! o inches long and eighteen inche diameter, with spokes of split oak, and one-half inches wide at the hub four inches at the rim. The felloes made double, bolted together with thr: quarter-inch steel bolts. he axles wi solid steel bars, those for the front whee being three and one-quarter inches thi and those for the rear wheels three one-half inches. One quart of a>: grease was required for each hub at ea greasing. The tongue reached only to the coll of the “wheelers,” or rear pair of mul which did all the turning of the wago1 the other eighteen mules being uset only for hauling. This tongue was solid piece of straight-grained oak, whi: as I remember, cost $50 in the rough. there were two wagons to a team was eight incl square at the w ee ee THE CHANGING WORLD on, and five incl e wenty les square at the fri 1 “ . - hauled, each trip, FOr some thirty years all the supplies for and end. Fastened a load of about ore from the mines located in the mountains the end ot . aurra ti 1] i¢ . thirtv-one tons. ex surrounding Death Valley, Calif., have been tongue was a cha | Pal hauled in and out in huge wagons, drawn by clusive of the water : ; “ptr teams of ten pairs of tank which trailed mules. Driving these with links of 1 teams, fighting off renegade Indians and bad inch steel, haz behind. the feed white men, became a profession requiring a cool made. runnii for the animals and head, quickness and accuracy with a gun, knowl- “1 o] hm wart seen re = ae wes edge of mules, and resourcefulness. Now the through the ent men, and the driv er and his “swamp- fornia desert on these wagons VA were seven feet in tireless motor truck, laying its own steel road, making two trips to the mule team’s one, and e! or. assistant. hauling more freight at each trip, has driven the ear o ’, last of the twenty-mule teams from the Cali- hea : The rear wheels team, bolted to t whiffletrees at t! each pait mules and c nected by Ste r + chains to their c:

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POPULAR MECHANICS 611 Seat; the “‘Swamper”’ here yokes, since the entv mules were trained to pull together e one team. Each mule was connected he singletree with wide leather braces. he team was driven, not by reins, but i single quarter-inch, smoothly woven running from the driver's it to the bit in the mouth of the right- ind mule of the lead team, and thence sing to the bit of the left-hand mule the same pair, where it ended. The im was turned to the right by pulling this rope, and to the left by slapping e neck of the right-hand lead with it. o execute this slap required consider- ble skill on the part of the driver, as id also the handling of the whip which 1a handle six feet long, a twenty-two oot lash, and was used merely as a cracker’ above the backs of the mules he driver had to use both hands and is body when he wielded it, and he also irried a box, filled with small pebbles, on the seat beside him. These stones he hrew at individual mules when they did not do their share of the work. It was rt of the duty to see that were no und rope, «if swamper's One of the Trucks Which Gather the Ore Trailers and Haul Them to Stations Where the Tractor Trains Are Made Up Jacob Allred, Last of the Twenty-Mule Drivers and Author of the Accompanying Article, Is Shown on the Standing beside the Wheel Gives an Idea of the Size this box was kept filled, and some of the drivers became real experts in “layi down” a stone on the back of a mule which needed encouragement. Since none of the twenty mules. except the wheelers, could help in holding back the wagon on the dow ngrades, the brake on the wagons were huge affairs, with handles’ made of steel bars, two inche wide, three-quarters of an inch thick and ten to twelve feet long. To use such a brake on the front wagon, the driver stood up on the seat, letting the tear follow the leaders, and threw his whole veight on the upper end of the bar, while the swamper braked the rear wagon. Ii the brake broke, the whole went into a pile at the bottom of the hill. With such an outfit, a water tank trail ing behind, and an extra, or relief, pair of mules led back of that, we drivers hauled $5,000 to 46,000 pounds ot ores from 300 in Death Valley, and from the mountain ranges on either side of the valley, some 140 miles into Johan- nesburg, and 120 miles or more into Dag gett. We dodged Piute Indians, renegade \paches from the reservations in Nevada, New Mexico and \rizona, fighting them h id to; men; feet below sea level, 1 wnen we et line t -ce white tanding of worse whit calculating our dav’s run so as to reach a water hole, which, often than not, was dry more } when we arrived; protecting our teams and ourselves from heat and from the deadl idewindet the small rattlesnakes ot the desert, and, with all thi main taining regular schedules. with mail and food supplies for the mines and the lonely ranches on both sides of Death Valley Much depended on the lead ing team of mules If thev un derstood their duties and _ did

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612 them, the remaining eighteen animals fol- lowed through. If they did not, the driv- er had a job cut out for him, because he had little or no control over the long team except that which he could maintain by | the “tunkline” working on the leaders. In the old days, such a team was vorth all the way up to $1,000, but when my team was disbanded, I bought “Jane” and “Judy,” who had been my leaders for more than six years, for $100, and the boss was glad to get that for them. What has become of the other drivers, I do not know, probably many of them are work- means oO! POPULAR MECHANICS mountains around Death Valley. Ths completely destroy anything they hit they fill canyon trails with bowlders whi cannot be moved; they slide whole mout tains into valleys overnight; they fill u springs and water and they s completely change the topography of th: country in a few hours that even an ol “desert rat’ will become lost. Fred Hinkle, whom I mentioned be fore, drove an express buckboard pulled by tour fast mules, prior to becoming teamster for the twenty-mule-team outfit In the early nineties, while Hinkle wa holes, Truck Train, Outward-Bound to the Mines with a Load of Lumber and Supplies; These Outfits Have Con- quered the Worst Perils of the Desert and Speeded Up Transportation ing in distant parts of the desert, and some are dead. For twenty vears, I drove a twenty- mule team. Before that, | was a swamper for Fred Hinkle, the king of the twenty- mule-team drivers, and the quickest man with either rifle or revolver who ever picked up a tunkline and shouted “Yo-r- r-rup” to a score of mules all tied to- gether. When I started driving there were forty of us. We were paid $100 a month and our food, bedding, guns and ammunition, while our swampers got $80 a month. If we had trouble on the road, either with men or with weather, and pulled through to our destination with mly small loss of time, we received a $5 bonus, and there were very few trips in those days in which the teamster did not meet with bad Indians, desert sand- storms or dry water holes. Don’t laugh when I say that cloudbursts were among our Worst troubles. These sudden down- pourings from the covering often only a tew acres, are frequent and deadly mn the the desert and in the skies, plains of so engaged, there was an epidemic of rob beries by white men all along the trails into and out of Death Valley. Hinkle, who was then nearly fifty years old, but hale and strong, put two old revolvers, loaded with blank cartridges, in holsters and fastened one to the dashboard, with the other on the seat, just beneath hi right hand. Then he strapped on two short-barreled double-action guns, under each arm, and put on a blue-denim jacket, concealing both weapons. At Indian Point, two white men held up Hinkle and his express buckboard Making him get out of the vehicle, the took the guns from dashboard and seat and started search for a package co1 taining $5,000 in gold, the pay rol! of mine on the eastern side of Death Valle. Regarding Hinkle as_ badly fright ened, one of the robbers lifted the seat cushion while the other searched for th: valuable package. The instant the turned from | one nim, Hinkle whipped out nh other guns and fired, killing both bandit firing left and right at the same time an

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POPULAR MECHANICS 613

Shoveling of the Ore from the x ae ee Mule Wagons to the Cars Has — =

Been Eliminated by a Special Sah Dumping Platform and Hopper ‘hee Used by the Truck Trains be ;

A Twist of the Wrist, and the Truck Entrance to a Mine in the Furnace Load Is Dropped into the Waiting Creek Mountains, on the Car, Eliminating Eastern . Side of Death Valley, Which for | Waste of Time Twenty Years Shipped Its Ore and Z in Unloading L Received Supplies by Mule Team J ve y, “= “SQ uPPER DEATH ™

ra fiw <. DAGGETT

o L- A —— B 1 Cactus hich 5 od: arrel actus, Which Has Saved Many Lives, and Map of the Mule-Team Routes in Death Valley (Dotted Lines)

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614 using only one bullet from each gun. Bill Ferguson was another of the great- est of the twenty-mule-team drivers. Bill arrived at Maybe Point one night, on his way from Daggett to Bennett Wells, on POPULAR MECHANICS hitched up the twenty mules, and droy the 100 or more miles to Bennett Wel! feeding and caring for the insane man :; the time. Arrived authoritic there, the mine Mining Camp on the Rim of Death Valley, and a Few Feet above the Level of the Pacific Ocean, 200 Miles Away; the Valley Itself Is 300 Feet below the Level of the Sea the northwest corner of Death Valley. With him was his swamper, Charlie Meiser. During the night, Charlie went violently insane, fleeing into the hills un- der the hallucination that the Indians were after him. Ferguson followed the unfortunate man, caught him, knocked him unconscious, carried him back to camp, tied him to the wagon and went back to sleep. In the morning he made the swamper as comfortable as possible in one of the wagons, watered, fed and would not take charge of Meiser, so Fe: guson carried him back to Daggett, dri ing, feeding, watering, hitching up t! mules, standing guard at night, sleepi: a little by day on the wagon, braking t! heavy loads down the grades, and mea while taking the best care of Meiser. If driving the twenty-mule teams wa a hard life, survived only by hard me: nevertheless it built up character, r sourcefulness, courage and friendship which endured until death. DEFLECTORS FOR AUTO LIGHTS ELIMINATE DIMMING The bother of turning a switch to dim the auto headlights is eliminated by using a set of curved shields which direct the Saveeens Se | Deflectors in Place Showing How They Bend the Head- light Rays Downward to Prevent Glare . rays of the lamps downward to the road- way where they do not shine in the eves of approaching drivers, yet suthciently il- luminate the path ahead. It is not neces sary to dim the lights at all. The shield consist of four elliptical visors, easily at tached by removing the lens and rim fro: the headlight and fitting them inside tl rim where they are held fast by a flang: They rest in front of the lens so that the do not conflict with state laws. A ELEPHANT CEMETERY MYSTERY CLEARED BY SCIENTISTS One of the most persistent “traveler tales’ from Africa concerns the myst: rious elephant “cemeteries,” seclude spots, where the huge beasts were thoug! to retire, when oldage or sickness overtoo! them, and wait for death. The basis fo: the stories is found in native legends an received apparent verification in colle tions of elephant bones discovered in vat ous parts of the country inhabited by t! herds. But after considerable investiga tion, scientists and big-game hunters hav:

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POPULAR ded that the ceme- ies are not the result a peculiar habit of the phants but are due marily to the question water supply. Herds ke repeated visits to luded spots w here re is anabundant ount of good water drinking and bathing, they also use these reats for hiding. In urse of time, the bones elephants that died r these places have ‘umulated. In one of cemeteries, it was lent that all the bones suffered about the me amount’ of weath- r indicating that the sts had died at about same time. Careful ] iirv among t h e old n of the native tribes ittered the anparent stery surrounding this 1. Years ago, the ele- int country vis- by a severe drouth. ings of pure water ed up and only those it contained a poison- chemical remained. en as well as animals ed from drinking it. ecause of their great e, the bones of the ‘phants are about the remaining evidence of the great ith, and it is believed that legends of he supposed elephant were pired by the remains found there. was cemeteries ALARM SCARES BURGLARS AWAY BY FIRING OFF GUN protection against burglars, an rm that fires blank or loaded cartridges now on the mar- t. It consists of short-barreled in fastened to en- ances by rough the base, nd has a sliding reech block and a ing-operated hammer ring, when the door is opened. Sixteen- iuge shells, or a charge of gunpowder ind photographer's flash powder simply to scare the intruder, may be used. For screws by a released MECHANICS 615 Mr. Benda Putting the Finishing Touches on His Huge Mask of the ‘Green Monster” ; Smaller Masks at the Left of Figure ART MASK OF “GREEN MONSTER” DESIGNED FOR BALL and decorated huge mask fa ened by W. 7 York ball Che creation figured silk 1 colors, a Garbed in with brilliant “vreen monster’ was desi Benda fora New is a development of the famous character | 0) masks which this artist devised for stage use. They are intended to portray domi nant traits of the persons represented, and fit the face closely. GRASS-FIBER BUILDING BRICK shredded fiber ot palmetto, sea grass or aterial appeared on the building markets and are isfactory in various types of construction. Bricks prepared from [ other similar have said to have proved sat hey are considerably larger than the or dinary brick and can be arranged to form their own mold for reinforcing pillars of concrete, or on like jobs.

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616 Removing the Phonograph Cov- er to Change Rec- ords; Doll’s Cloth- ing Conceals Top PHONOGRAPH HIDDEN IN DOLL PLAYS CHILD RECORDS Concealed inside the body of a “talk- ing’ doll introduced in Paris, a small phonograph plays records which repro- duce the voice of a small child. 30th song and speech are faithfully imitated. Mechanical noises are said to be almost inaudible because of the construction, and the records can be changed easily. DRAIN ON ELECTRIC CURRENT HEAVIEST TUESDAYS The peak load in the consumption of electricity for domestic purposes comes, not on Saturday nights, as many persons believe, but on Tuesday morning about 9 o'clock, when housewives are us- ing their electric irons after Mon- day’s washing, a city survey shows. Fewer hours of daylight in the winter months naturally require more artificial illumination and a consequent increase in the electric- light bill, but few consumers know exactly how much longer thev need lights in winter than they do in summer Statisticians have figured that, in june, an average of only about 2.55 hours out of the twenty-four, see artificial lighting in the or dinary home, whereas there are about 6.85 hours ot electricity burning each day in December. POPULAR MECHANICS SECRECY FOR RADIO MESSAGES BY USE OF DICTAPHONES Far greater use of the radio is seen the result of the invention of a Britis scientist who is reported to have found way to keep secret Instead of using the beam-transmissi: system, his apparatus is purely mechan cal. It [ dictaphone wireless messages consists of a int which the message is spoken and recorde upon a register that turns at irregul speeds through the use of elliptical gear The finished record is then made t “speak” backward into the radio tran mitter. At the receiving station, anothe dictaphone with a record turning at th: same speed at which the first revolve registers the message. By reproduci: the result in a certain manner, the origi nal is made intelligible. HINGED BOWLING PINS KEEP SCORE WITH LIGHTS Lovers of bowling can enjoy a modifi form of the game on a miniature alle only fifteen feet long. It is played wit a cue or stick instead of the usual wa The pins are hinged, and when they ar: struck, the lower part flies up out of t! way, completing an electric circuit whi lights a tiny lamp on a board at the re of the allev. There is a light for eac!] pin. A glance at the board tells hi many have been knocked down. The are quickly reset by an automatic rack ing device. Removable leather tips ar: provided for the pins to protect them and insure even The game scored in the same wavy as regular bow! ing. The small size of the alley adapt it to rooms of limited area. wear. Bowling Game Is Played with a Cue, and When Pins Are Struck, They Reg ister Score in Lights on Rear Board

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POPULAR MECHANICS 617 Clouds of Flame Leaping from Pipe at Naphtha Well; Excess Gas Is Burned in This Way After Rest of oduct Has Been Consumed in City Near By FLAME FROM ICE-COATED PIPE BURNS EXCESS GAS eaping the year around from a frosty ‘at a naphtha well near Calgary, Can., \00-foot flame consumes surplus natu | gas produced during the refining proc- es. It has burned about two years, and is estimated that gas valued at approxi- tely $7,000,000 has been destroved in is manner. RADIO FOR CATCHING THIEVES DETECTS LOOT Radio has been used for some time by the police in spreading information to as- t in the capture of criminals, and now n inventor has devised a new way to ip thieves by He utilizes the oot itself to accomplish wireless. or search. The apparatus is arranged so that a reasonable amount of metal, knives and watches carried by the men, will not produce a cause unnecessary delays at quitting time. sucl as coins, . 1 , Signal ane WOMAN AS FISH TAXIDERMIST WINS WIDE FAME Although her friends advised her not to attempt the work, a California woman has become a successful fish taxidermist and receives orders from sportsmen in nearly every part of the world. She has become an expert at mounting specimen and not long ago prepared a huge sword fish, weighing over 570 pounds, for ex- hibit. This species is considered difficult for the taxidermist, on account of the great quantities of oil it contains purpose. The system for installation at the ntrance to factories, other places tools or metal ‘hjects are likely to be tolen. The gateway is electrically wired in a spe- al manner, and the atchman, wearing a radio headset, listens as men pass out. If they carry an inusual quantity of metal, noise is heard in the mines or here ores, } 1 hones and the person can Finishing Work on a Flying Fish; Woman Taxidermist in Her Studio Sur- be halted for questioning rounded by Specimens Prepared tor Sportsmen

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POPULAR MECHANICS 619 2 : 7 Sa ee Ee sd a . Fair to Celebrate Triumph of Invention American Progress in a Century and Half to Be Outstanding Exhibit at Philadelphia’s Sesquicentennial Celebration ECHANICAL geniuses, both ama- teur and professional, are going to find their Mecca in the Sesquicentennial International exposition which opens in Philadelphia, June 1, in celebration of the 150th anniversary of the adoption of the Declaration of Independence. The Palace of Machinery, Mines, Metallurgy ind Transportation will be the particular magnet that attracts them. The palace is the largest exhibition building in the exposition, with floor pace covering ten and ‘one-half acres. lt cost approximately $1,250,000. Here will be found countless exhibits presenting the last word in mechanical nd electrical invention, in many in- stances accompanied by the earliest ex- mple of a similar contrivance, showing at a glance the strides made in the im- provement of the article since its origi- nal invention. Other exhibits will trace the progress of a mechanism through the arious stages of development to pres- ent-day completeness. The power for driving the machinery exhibited will be developed in full view of the visitors. One turbine manufac turer will have a steam turbine directly connected with the generating set pro- ducing the electric current for power use. 4 Three uniflow steam engines will be in operation. Diesel-engine direct-connected genera- tor sets, ranging from 250 to 8,000 horse- power form an exhibit never before equaled. Ice and refrigerating-machinery exhib- its include an entirely new invention re- cently developed by one of the largest companies in that line of manufacture. Exhibits of machine tools and of ma- chinery and equipment for railroad shops, and iron and steel works will cover every mechanical detail of these industries. Transportation equipment of the most recent invention will be displayed. Side by side with the latest tvpe of electric and steam locomotives will be shown the first locomotive used in the country. A railroad turntable of the articulated type, 118 feet in diameter, on which steam and electric locomotives alternately will be mounted, is a prominent feature. Ele- vated six and a half feet above the con crete floor of the building, its design and the electric drive mechanism may Il easily examined by visitors. The en gines will be run at a speed approximat ing thirty-five miles an hour. The steam engines emploved weigh 310,000 pounds and the electrics from 332,000 to 360,000

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620 POPULAR MECHANICS The aviation exhibit will cover all types o aircraft and apparatu from two-passenger airplanes to those con veying twenty-four per sons. The aviation field at the exposition, cove ing 120 acres, will be the scene of many flying events arranged by the military and naval au thorities and aeronauti organizations. Radio fans will come into their own at the ex position. Inspectionar study of the numerou exhibits will come ver near to satisfying the de mand for more and still more knowledge of the subject that is fascinat ing millions of minds the world over. It is.the first world fair at whi such an exhibition possible. The wonder of the radio will mar! the topnotch of advance ment in civilization. Steel manufacture: will show every phase o! the industry from the mining, refining and chemical treatment « The Tower of Light, One of the Many Illuminated Features in Which Lavish Electric Displays Will Be Used pounds. In transferring the locomotives to and from the turntable, two methods will be demonstrated, that of employing overhead traveling cranes and that of using wrecking cranes. An entire Pullman train of five cars of up-to-date construction and equipment will show, by contrast with some of tl earliest Pullmans, the progress made in this line. The oldest and latest types of freight and passenger cars and street-rail- way cars will also be exhibited. The automobile industry will have a Leading manu facturers will exhibit the various types of cars, trucks and busses; chassis, tops and bodies, as well as accessories, tools and supplies. Marine transportation will be repre- sented by steamship models, yachts, mo- torboats, marine engines, deck machinery, maps, charts, navigation instruments and all recent inventions applicable to water transportation. ie strong representation. ] the various ores to thi finished product. An in teresting part of this ex hibit will be the first-aid and sanitary welfare system employed by the majority of the larger companies. A house, built almost entirely of rust- less steel and equipped throughout wit! furniture of the sare metal, presents the last word in fireproof construction. The carpets, upholstery and draperies wit! which itis furnished, being treated with chemical preparation, are likewise non inflammable. The structure composed of standardized parts, bolted together, and a garage of similar construction wil: be found located near the Palace of Machi: ery, Mines, Metallurgy and Transporta tion. About thirty leading steel-manufac- turing companies in the United States are members of the association which con structed it. Each firm has its own exhibit in the palace. Oil companies will show the drilling 0 wells and refining processes, and will dem onstrate many things of interest to the ever-increasing number of oil users. a- mi

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POPULAR MECHANICS 621 7 3 ue. Rghe g i“ e Vestibule of the An Enormous Liberty ilace of Agriculture, Bell, Studded with d and Dairy Prod- 20,000 Electric ts Shows One of ae : Lights, Will Span the Lovely Vistas of ‘ the Main Ap»roach the Exposition through Philadelphia Colonial Architecture, Reminiscent in Its Stately Simolicity of the White House, Has Been Selected for the Big Administration Building

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622 POPULAR Fire-fighting equipment will form an interesting display and serve to make more clear to the man in the street the methods of battling with flames than he is able to grasp in the hurry and bustle attending a real fire. The advantageous burning of powdered coal will be demonstrated by the exhibits of a number of manufacturers of boilers and mechanical stokers. Electrical-machinery manufacturers will motors, generators, switchboards, switchboard apparatus and endless other lines of electrical equipment and supplies. \ large section of the palace is devoted to this industry. The progress of the Bell telephone, first put to public use at the Centennial expo- sition of 1876, and at that time regarded by many as merely an interesting toy, to the development of the dial system and other late improvements will interest thousands of visitors. Great interest will by the exhibit of recent inven- tions for sending pictures by wire. The foregoing are but a few of the ex- hibits that will interest and enthrall the man of mechanical bent. No greater tes- timony to the degree of civilization reached by a nation but a century and a halt old could be offered than is presented by the collection of modern wonders housed in the Palace of Machinery, Mines, Metallurgy and Transportation. The two buildings ranking next in size are the palaces of Liberal Arts and of show be created MECHANICS Manufactures, each with floor space of eight and a half acres. The stadium, accommodating 100,000 and providing additional exhibition space beneath the tiers of seats, covers five acres. Here will be held historical pag eants, gala musical festivals and athletic games on Olympian scale with champions from all parts of the world in competition. The auditorium which seats 20,000, pro vides three acres of floor space for the many conventions that will be held there during the summer. Concerts and othe: entertainments as well as lectures « nany subjects will be given from time t time. The administration building provides quarter of an acre of space for the execu tive conduct of the exposition. A of additional buildings represent the pa ticipation of as many foreign, gover ment, state and commercial interests. The Gladway provides a circular pro enade of a mile and a quarter, along t! outside of which are situated the amu ment features and other concessions co tributing to the lighter side of the expo tion. Inside the Gladway a beautiful par inclosure will be found, with twelve acre of lagoons adding charm and variety the landscape. Motion pictures made on the spot be a compelling attraction at the “Se qui.” The mysteries of the studio will b unveiled at the local Hollywood erecte on the grounds, where leading cinem SCOT The Portico of the Huge Palace of Liberal Arts, One of the Largest of the Exposition Buildings, Shows the Attractive Simplicity Obtained by the Use of Tinted Stucco for the Walls

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will take tures. he grounds of the exposition adjoin League island navy yard, enabling tors to inspect the yard, in itself a teworthy governmental exhibit. \rchitectural design of the exposition dings shows the influence of the t modern set-back type of office ilding developed by present-day ning laws. Large unbroken wall ices of pastel-tinted stucco, decorations in the more vivid mary colors, supply a rainbow fect which is supplemented by orful floral schemes in the rounding landscape gar- ning by day and by turns in making actual nique lighting features night. fhe lighting arrange- nts are unprecedented the history of artificial umination and will not confined to the exposi- on grounds. The city of hiladelphia extends north nd south approximately elve miles, and west rom the Delaware river bout six miles. Through- ut this area, and far be- ond in all directions, will e reflected the luminosity some of the most spec- icular lighting effects er attempted. Concentration of 6,300,- 00,000 candlepower at a oint beyond the new Art luseum, situated at the lain entrance to Fairmount park, some ve miles from the exposition, will not lone flood the city with light but will onstitute the Philadelphia aurora visible New York, Baltimore, far inland, and or miles out at sea. This will be accom- plished by massing fourteen super-power earchlights fitted with projectors and lor screens to throw fanlike and criss- ross rays in all the hues of the rainbow. \ spectacular effect will be produced resembling nature’s aurora borealis or northern lights. The tower of the City Hall, which is sur- mounted by a colossal statue of William Penn, thirty-seven feet high, and situated ibout a mile from the Art Museum, will be thrown into strong relief by powerful -earchlights placed back of the buildings ind casting a glow of pink light. The parkway connecting these two points will be an avenue of light. POPULAR MECHANICS 623 Deer with One of the ~ a Arrows Still in Its Side; Shot Was Made by Woman Archer at Twenty Yards WOMAN ARCHER KILLS DEER AT TWENTY YARDS That archery is not only a pleasant diversion but holds possibilities for the modern hunter is seen in its revival in the quest of big game. What trusty bow and arrows will do, even in the hands of a woman, was illustrated recent] when a young huntress in brought down a deer at twenty vards Three shafts were used, all striking ne the animal’s heart. rood aim l Loui sana @lf cave men were healthier than people today, one reason that they didn't eat so much, according to an English s« entist, who asserts that one cause ot can cer and appendicitis is overloading ot t] stomach and that modern men from three to four times as much food a consume 1 ? GaV as ell Was stone-age ancestors.

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O24 POPULAR U.S. SPECIALIST IN CIGARETS AIDS MANUFACTURERS Collecting countries ot samples of cigarets from all the world where they are © H. Miller Mr. Hill Collects Sample Cigarets, Not as a Hobby but to Aid Tobacco Merchants produced, is one of the tasks of Benjamin 1). Hill, tobacco specialist of the depart- ment of commerce. From his testing and examination of the specimens, he obtains data helpful to American manufacturers interested in exporting their products. More than 10,000,000 cigarets are sent from the United States to foreign coun- tries every year. MYSTERY OF ICE BLOSSOMS SOLVED BY SCIENTIST On cold, frosty mornings, from Novem- ber to January when the ground is not frozen, delicate white “blossoms” of ice are frequently seen on the stems of vari- years ous kinds of plants. For many scientists have been puzzled as to the manner in which these crvstal formed. Did they develop, just as frost does on a window pane, as a result of damp- ness from the surrotind- flowers were ing air or from mois- ture inside the plant itself? From experi- ments conducted by Dr. W. W. Coblentz, of the bureau of standards, it appears ™@ that the latter is the fy correct explanation, + and that the mois- Examining Motor MECHANICS Number with Chemicals ture which produces the blossoms origi- nates from the little sap tubes in the stem of the plant and not from the pith, as an other scientist had believed. To solve the question, Dr. Coblentz cut a bunch of dried stems of a plant which has many sap tubes in its stalk, peeled the bark from some of them, mounted the collec tion in a heavy piece of pasteboard and cemented it in tightly. The ends were in serted in a glass test tube partly filled with water, and they were then placed on a window sill ona cold, frosty night. They were carefully covered so that the mois ture from the air could not be deposited upon them. One of the stems that had been sealed, to keep the water from be ing drawn up through the sap tubes, formed no fringes or flowers, but all the rest did. Further tests were made by coat ing the stems with shellac. No fringe were formed, indicating that the moisture had to come up from within the plant To make sure that the bark did not carry the necessary water for forming the fringes, the stems were coated with a sub stance which would keep any moisture from creeping up the bark, and the test tube was filled with colored water. The next morning, the dve was discovered oozing from the stems, showing conclu sively, the experimenter declared, that it had been drawn up through the sap tubes Further proof was seen in the fact that in each case considerable water had dis appeared from the test tube. These ice flowers often form on pieces of unglazed pottery lying upon wet soil. ALTERED NUMBERS ON MOTORS DETECTED BY CHEMICALS Philadelphia petice have tested a way of detecting alterations in the manufac turer's numbers on automobile engines that promises to aid in the identification ot stolen cars and cap turing the thieve First, a special chem ical is applied to the number, which is then heated with an acetylene lamp and a second coating with a different chemical ipplied. When a photographic im pression is made, the original number is said to appear in spite of any altera tions that may have been made by a thiet

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POPULAR MECHANICS 625 \ OVIE PROJECTOR IN SUITCASE NEEDS NO OPERATOR

fi

\Vith a compact mo- picture projector on the market, films hown without the f a skilled or li- operator, for the rewinds as it un- ind power for turn- furnished from a socket. Projection be made upon a wall ( ]

<—* e u en or upon a collap- Eecretary of the Navy Wilbur and C. Francis Jenkins, the Inventor, Exam- ining Compact Movie Projector; In- sets Show It in Use

e shadow box at- hed to the case, only five deep, about eighteen inches long lightly less in height. It weighs less \ feature fifteen feet so, the pictures are as large as at a tance of seventy feet with an ordinary In case the film breaks while switch automatically Because of the way the 1 is wound, there is said to be less wear, a safety sixteen-millimeter size is ed, keeping the cost of the prints to a Intmum. Che is specially uted for schools, business purposes and vhich is ventvy pounds complete. at, with a range of only ector. ing, a machine. stops projector 1S for lecturing as well as for amusement at home. It holds up to 1,000 feet ‘of film LIFE LINE IS FIRED BY RIFLE TO AID SEA RESCUES Fired from the shoulder like a sporting gun, a special rifle for shooting lite line to persons in shipwrecks, is also used by steeplejacks in fastening cables to h | chimneys or other places. A long rod fits into the muzzle of the rifle, and to it is attached a line seventy vards long It sO arranged that the bullet can be accu strong rately aimed and is very

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626 POPULAR MECHANICS foun Jake Schaefer, ° zo Weide is? saine [Magic in Ivory Balls Solved Son of a Famous Cham- e e tration, Ie Noted ior by Diamonds Which Make Nerve and the Perfec- Amateurs Experts By J. EARLE MILLER tion of the Bridges He Employs in Such Diffi- cult Shots as This Masse, in Which the © Cue Ball, Twice De- J scribing the Arc of a Circle, Strikes Both . Object Balls NV AKING a trio of ivory balls perform weird ¢g 4 tions around a green-felt table by the applicat of simple mathematics bids fair to make three-cus! billiards the leading favorite of all the ivory-ball ga: Through the application of an ingenious “diamond tem” any inexperienced player can determine off-] where to shoot to make the necessary th: caroms off the cushion before the second ject ball is hit. The mathematical diamond game is so cinating that, at the University of Chicago class of college professors, including Albert Michelson, the famous mathematician, has b: formed to study it under a professional coa Three-cushion billiards thrills the spectat and amateur player for the same reason t! a free-hitting baseball game or a “Red” Gra on the gridiron does—there is more action to 3 The tournament game of 18.2 balk-line billia: is like a no-hit, no-run baseball game, a fine « ample of great skill, but not very thrilling the spectators, or the opposing players. Young Jake Schaefer, the balk-line champi and Edouard Horemans, the Belgian, ft whom Schaefer recently regained his title aft losing it the month before, frequently run fr 100 to 200 or more points at a time, display: remarkable skill, but such long runs rather la excitement for the balls are grouped toget! and then nursed along with the minimu amount of movement required by the rul The three-cushion game, on the other hand, fords plenty of action, but, until the diamo system was perfected, many amateurs tou it too difficult. The mathematical system of computi angles at which shots must be made to get t necessary bank from threé cushions, derives name from use of the iv diamonds inla in the table ed as guide marke It is only nec sary to memo two sets of nu bers, one for cue - ball posit! and the other the object b and then subtra the latter fr: the former, t

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POPULAR MECHANICS 627 The Diamond System Reduces Three-Cush- ion Billiards to Simple Mathematics Cue-Ball Lines, in White, and Object-Ball Lines, in Black, of the Diamond System; Showing How They Crisscross the Table Subtract Two, the Ob- ject-Ball Number, from Five, the Cue-Ball Posi- tion, and the Difference, Three, Gives the Dia- mond at Which to Aim

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. *) 62 difference indicating the position on the table at which the cue ball should be aimed to strike three cushions before the object balls. The player still must estimate the proper amount of “English” to use, and can dis- play his skill at calculating the direction the cue ball will take after striking the first object ball, when the two are sepa- rated. The diamond system only solves +} ie first, and purely mental, problem of here to shoot, leaving the rest to the in- dividual skill of the plaver. The simplest of all three-cushion shot ith the cue ball in one corner and the two object balls together in another, illus- trates the basis of the system. The cue- ball numbers, starting with the first dia mond at the other end of the table, run from one to five for the corner diamond and up to eight for the three end dia monds. The object-ball numbers, start- ing around the end of the table, run from zero to four and a half, the two coming in the corner. Thus, the cue-ball num- ber in the corner being five and the ob ject-ball number two, the difference is three, and the player, counting diamonds irom the opposite end of the other side of the table, aims at the third diamond. The ball caroms off the side cushion, strikes the end, banks straight for the sec- ond diamond on the other side, and from there to the opposite corner, striking the two object balls. { POPULAR MECHANICS When the balls get out into the midd of the table, the game becomes more co1 plicated, unless the imaginary number: lines are well memorized, since the li: are not parallel, half numbers resulting converging lines. The opposite end the cue-ball line is always determine however, by subtracting two from t! number for the near end, and counti: back from the other end of the table f: the resulting number. Thus the numb three cue-ball line, after subtracting t from three, should end at the first d mond on the opposite side. The fascination of pool and billiards largely due to the mathematical exactn: with which the most erratic-appeari: gyrations can be duplicated time ai again by an expert player. Masse shot at which Horemans, the Belgian playe: is an expert, often apparently defy all t! laws of reasonable conduct. A masse a curved ball which starts in one directio: changes its mind 4nd ends up somewher else, like a boomerang. When you Schaefer won the title from Willie Hop he was forced to use one of the most « ficult of all masses, with all three balls line along the rail, the two object balls | ing so close together’ that it was imp: sible to hit the first and send it out at while the cue ball would follo through to complete the point by hittin the second. Instead Schaefer massed t!] cue ball out in a curve that circled aroun: angle Two Difficult Fancy Shots, a Three-Cushion Kiss Shot off the Red Ball, Above, and a Three-Cushion Time Shot, Below, Demonstrated by Al Taylor, One-Time Challenger for the World's Balk-Line Championship

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ternational Billiard Tournament Staged in a San Francisco Church Auditorium; Fans Gather Each Year to Watch the Ranking Stars Play for the POPULAR MECHANICS 629 bbiebinnine gene ecm a 4 goa viene ° rein ry ey e back, struck the farthest object ind glanced on to the nearest one shot, as Schaefer plaved it, is illus- ed in the center picture on page 631, le, just | velow and to the right, is the er form, where the distance between alls is sufficient to drive the first one of the way. lany of these complicated shots re re intricate bridges” formed bv the rs. Schaefer is noted for the perfec- his bridges, his long flexible fingers ling backward, but steadving e most difficult positions and holding easily re without a tremor while the shot is ng made. Schaefer’s history is the story of a ing man who followed in his father’s itsteps so well that he has won the me championship since it rs and special ting I the world’s balk-line incidentally, is no empty hon- is worth $6,000 a vear to the ries with it exhibition opp tunities for one’s skill alt which is Sie It also cat demon . of which pay we ll. Schae ie elder Jacob fer was one of the great billiard players and did mucl ‘stablish the position of the game. His born in 1894, was only 27 when he ed the veteran Willie Hoppe for the Huge Title Galleries of Billiard title by running up a grand average of 10 points to an inning, which almost reached the record of 551947 which Hoppe had set seven vears before How far billiards h advanced in the five ears ince Scl iefer won hi first title is indicated b the fact that he avet aged 9334 for sixteen inning when defeated Horemans in January of tl vear. while even the lose beat Hoppe's old record by a fraction of a point. Schaefer has set manv records in tout nament play, but one of the most unusual as during the 1925 tournament, when lh eliminated Hagenlacher bv the unique core of 400 to 0, his opponent never hav ing a chance to climb down from his stool 1d try is luck Schaefer won the bank at the start and ran out the 400 point without a stop In the oeey game of the tournament which markee 1 Hoppe’ s retire ent, Scha fer again ect a remarkable run ot 296 points The skill required to make s¢ hun dred successive play ithout faltering enormous, al dd t} e nerve nece i? to ad it betore a crowded auditorium oft lv enthusiastic billiard till greatet His coolness served Schaeter well in h

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6350 ast match with Horemans, who is in- clined to be excitable, but failed to help him the month before when the challenger von the title. On that occasion Hore- mans got away to a good start, and the champion was forced to sit on his stool most of the evening. At one stage, the Belgian had run up a score of 467 to 11, but Schaefer finally got started and col- lected 301 before his opponent was able to run out the 500 score for the evening. The men who become champions, or of sufficient caliber to play in championship have a remarkable mastery over the ivory balls. Periect balls on a perfect table always perform the same way under given conditions, so there is no uncertain- ty about the expert’s shots. Some of the fancy shots, rarely seen in tournaments, are marvels of accurate timing, two or three balls in motion meeting at predeter- mined positions to touch and rebound on new courses, whence they strike other balls to complete the shots. In one shot, for example, the white cue ball, lying against the red object ball, drives the latter down the table, to re- bound from the end cushion and strike the cue ball, which in the meantime has remained almost motionless because of backspin applied by the cue. The cue ball, rebounding from the returning red ball, makes three cushions and eventually strikes the second ot the object balls near rames, POPULAR MECHANICS the other end of the table. The w! shot, taking a matter of seconds, is so curately timed that a billiard expert perform it over and over again. The old-time pool room with its un ory reputation has been largely elimin through the efforts of the billiard ma facturers and state organizations, both straight and pocket billiards, « threatened with general disfavor, put | on a higher plane. One result of change is the growing popularity of liard rooms devoted exclusively to wor FABRIC FOR CHASSIS BEARINGS MAINTAINS OIL FILM Bearings of a fiber composition inst of metal for the auto brake gear, stee1 and suspension system, and other p are said to be a suitable substitute bronze or white metal, to keep an e lubrication and, even when not oiled, ; duce little frictional resistance. The terial is capable of withstanding a p: sure of two tons to the square inch v out perceptible yielding, it is report The composition is not intended for hi important engine bearings, which ar: inclosed and highly lubricated, but « cally for the minor parts of the cha where heavy loads are borne, adequate brication is dithcult and squeaks rattles are likely to arise. Billiard Parlor for Women Only, One of the Newer Developments of the Game Which Has Found Favor Larger Cities, Where Both the Pocket and Cushion Game Have Many Feminine Followers

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POPULAR MECHANICS Masse Shot off the 1 : — = Farther Ball, Requiring ee ene Perfection of Bridge, Al Taylor Showing How Knowledge of “‘Eng- Three-Cushion Masse, in to Make a Three-Cushion lish,” and ron Which the Back-Spinning Shot off One Rail, a Dif- Nerve Cue Ball Makes Two ficult Feat Which Takes the Amateur Many Long Hours of Practice to Master Cushions on One Rail and the Third on the Other before Losing Its English Variation of the Shot in t! Center Above; Here the | Object Balls Are Farther Apart, So the Red One Is Forced Out of the Way Three-Cushion Draw Shot, Using Reverse English, the 3ail Making All Three Cushions in the Corner after Re- bounding irom First Object Ball

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632 POPULAR MECHANICS SHIP’S SPEED LIMIT RULED BY COAL Coal, and not entire] the limitations of a ve: sel’s propelling machi: ery, determines the spee at which it can operat with any hope of co: mercial gain, accordir to experts, who belie that the speed limit far as passenger liner are concerned has about been reached. This is b« cause of the enormou increase in the amount « coal required as t! speed is accelerated. Fo: instance, a ship of 16,0) to 18,000 tons’ displac: ment, when running thi: teen knots an hour, w burn ninety tons of c: a day, but if the speed increased to seventes knots, the consumpti of fuel rises to appro» mately 190 tons of co each day. At twent knots, the speed of a f Atlantic liner, nearly 34 tons would be require and at twenty-five knot over 900 tons a da} 4 As Boxes Bump About in This Revolving Drum, Weak Spots Are Revealed; “hese Tests Show Shippers the Most Durable Containers STRENGTH OF SHIPPING BOXES TESTED IN WHIRLING DRUM W hat kinds of stand the strain involved in Railway freight and express representa- tives, meeting at the forest-products lab- oratory at Madison, Wis., were given graphic tests of the strength of different kinds of crates and boxes by means of a six-sided drum, fourteen feet in diameter. Containers of various types were placed inside this receptacle which was revolved slowly. Bumping around placed inside of the drum and over its irregular surface, the bo X€S boxes will best with- obstructions received shocks and jars more than equal to those met in actual ship ping. Weak spots were revealed and Improper methods ot filling the crates also Gun for Lighting Gas; Sparks to Fly from Flint Tm : disclosed. shipping? Pressure on Trigger Causes From thirteen knots t fourteen knots an hou the extra cost for co would be only about $340, or so, for eac! 1,000 miles, but at twenty-five knots the cost would be $1,500 more than at twent four knots. A vessel of 18,000 tons’ di placement, running at twenty-five knot would consume approximately 1,500 ton of coal for each 1,000 miles. FLINT GUN FOR LIGHTING GAS SAVES USING MATCHES The hazards and bother of usin matches to light the gas are eliminated i a pistol-shaped igniter that directs a lh: spark from a flint upon the burner b pressing a trigge New flints can be in serted when need the lighter is alwa ready for use, and 1 harmless. @ Brazil's area proximately equa! that of Europe. POPULAR MECHANICS

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POPULAR MECHANICS \PAN CURRENT IN NEW PATH ALTERS HABITS OF FISH first thought, there seems to be no ‘t connection between an earthquake the fish market, but 633 AUTO-PARKING SPACE ON ROOF RELIEVES CONGESTION A flat-topped building has been utilized for automobile-parking space in Wash- varently there is. ortly after the Japa- e earthquake of 1923, japan current strayed new courses, taking warm waters into ferent parts of the in. According to iskan herring fisher- en. this has. materially inged the temperature the waters near the st, and as a result fish e been forced to find havens. MUCILAGE HOLDER AND DAUBER COMBINED Waste and sticky fin- rs are avoided when ing mucilage with a combination holder d spreader which fits inside a metal- pped desk stand when idle. The adhe- e is kept in an inverted glass bottle and vs through small openings in a coarse brie stretched over the smaller end. The ntainer itself serves as a dauber, even reading is possible, and the need of re- eated dipping of a brush is eliminated. Dauber in Use and Placed in Stand Out of the Way and Safe from Thieves; Autos Parked on Roof of Washing- ton, D. C., Building ington, D. C., to accommodate owners who work near bv and to reduce conges- tion in the streets. The aerial garage is reached by a freight elevator which opens upon the roof: there is room for several cars, and the plan prevents theft as well as damage from collisions that might hap- pen if the cars were left on the streets. SCREEN IS DARK HALF OF TIME MOVIE IS BEING SHOWN Few motion-picture fans realize that they are looking at a dark screen nearly half the time the reel is being shown, but such is the case, according to a well known photographer. Furthermore, each one of the tiny pictures that make up the reel,isseenthreetimes. In front of the pro- jection machine’s lens is a revolving disk divided into six parts, three being sections through which the light is allowed to travel to the screen. By a synchronizing system, this disk revolves once each time one of the little pictures, of which there are sixteen to every foot of film, stops be fore the opening. Thus there are three showings of each one of the views before it passes on to the next. The solid por- tions of the disk, shutting off the light. keep the screen in darkness about half oi the time, but the entire action is too rapid for the eve to detect. In filming a recent movie, 120,000 separate pictures were taken, making a reel 7,500 feet long.

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634 POPULAR MECHANICS el | Courts Harley-Davidson Motor C Daring Hill Climbers, Devotees of Motordom’s Most Thrilling Sport, both Ride and Are Ridden by Bucking Mounts IDING several hundred ninetv-mile-an-hour a forty-five-degree pounds of motorcycle up until the hill gets so steep the motorcycle reverses po- sition and climbs on top of the rider, is not everybody's idea of a pleasant after- noon. But enough who get a ] thrill out of the most dangerous sport in slope, there are motordom to make such climbs the most favorite form of outing for every motor cycle club that can find a suitable hill within a dav’'s ride of home. That hill-climbing is more dangerous even than automobile racing is not hard to prove. The auto racer has a sporting chance of escaping with a whole skin and on all four wheels. The motorcyclist who goes in for hill-climbing hasn't a chance. Somewhere between top bottom there is bound to be a spill, and when the rider lands on his back, jug- gling a snorting racing machine in the | bound to be some above him, there is damage to skin and, possibly, bones. k stunts and spectacular races have Frea been featured so much that the average person has the idea that anyone who rides a two-wheeler is taking his lite in his hands. Motorevecle men say not, and de clare their mount is as sate as the old- unless the rider delib- goes a-stunting. The motorcycle thrillers shown in the movies are not lightly undertaken by every two-whee rider, any more than all of them go for hill climbs. The motorcyclists 1 appear in the movies are usually trained stunt men who well realize l the hazards « the work, and are prepared, throug! fashioned bicvcle, erately 1 training and cool nerves, to cope wit! the dangers which threaten serious in jurv or death. The hill-climb riders are usually pro fessionals, many of them demonstrators for factories or agents, and thev entet the contests not onlv to demonstrate thei: own skill and provide thrills for the spec tators, but to show the power of the ma chine thev ride. With a dozen or more trained riders entered, thousands have as sembled to watch them send their mount up hills where they defied the law ot gravity, up inclines so steep that the, could hardly be negotiated on foot. Under such conditions it is not un usual to see the weight of the rider on the rear end overbalance the machine, send ing it into a back somersault from whicl ] on his back it emerges with the the ground and the machine trying to driver 636 POPULAR MECHANICS

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POPULAR MECHANICS ae When the Law of Gravity Steps In, the Hill Climbers Reverse Position and the Motorcycle Rides the Rider for a Change } Practicing a State Fair Thriller, Above, in Which the Motorcycle Passenger Transfers to the Rope Ladder from Above; Right, a Movie Stunt Not Rec- ommended for Everyday Practice After Riding down the Long Hill in the Background, This Man Injured Himself to Save a Woman and Child F

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636 fall on him. Sometimes, the motorcycle, with engine roaring, escapes and runs wild down the hill, chasing innocent spectators through the fields. Often, however, the trained rider not only gets control, cuts off the motor, but actually thé machine to the ground and averts a bad smash-up. One Pacific coast dare-devil recently departed from the usual custom of a free- for-all climb and went out alone to con- quer a mountain peak in the Rockies. His route lav along a narrow ridge of loose shale and rock slides, with sudden washes and canvons at intervals, and an enor- mous precipice under his elbow. The grade was too steep to try to take it at slow speed, so he simply gave the ma- chine the gas and dashed through. Steele, of Paterson, N. J., a noted east- ern hill climber, staged an unexpected thrill in a climb at Pompton Plains, N. J.. a few vears ago. The hill was about 500 feet long and ten feet past the finish line was a bank about four feet high. In practice, he used this bank as a stop by sliding broadside into it. “Everything went along fine until I took my first trial in the seventy-four- inch open event,’ Steele later said. “I had not turned my motor wide open in practice, so, when I started up-the hill in the trials, I turned it all on and held tight. Before I could realize it, I was at the finish and the crowd did not expect eases POPULAR MECHANICS me there so The result was that I had no chance to broadside into the bank, but had to ride straight over it to avoid running into the people. “IT hit the top of the bank and flew straight into the air over the bars and landed on my face. The machine turned a somersault and, as I looked up it flopped toward me. Luckily for me my mount proved loyal, for it finally landed right alongside of me. Except for a scratched face and a stiff neck for a few days I was all right.” Next to climbing of hills, motorcycle broad-jumping leads in thrills for the spectator, and danger for the rider. It was widely practiced during the war by army messengers, who learned to take an old trench line or a shell hole tn high and leap the gap. Given a slight incline to launch the machine in the air, a motor cycle going at full speed will jump any where from twenty-five to fifty feet, soar ing in an arc twenty feet or more above the ground and coming down, perhaps on two wheels or, as an alternative, spill ing the rider in the dust. A Canadian rider, Morris Moffatt, holds a world’s record for motorcycle broad-jumping, with a 210-foot leap from shore into the icy waters of Lake Ontario, while a tug stood by to rescue him. One of the most sensational motor cycle stunts ever staged for the movie cost R. B. Parrish two broken legs, the soon. ry: A thin Broad-Jumping on a Roaring Gasoline Mount Is a Game Full of Thrills, Even for Stead Speed, the Heavy Cycles Make Surprisingly Long Jumps from the Take-Off Boar a ; at High

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POPULAR MECHANICS 637 ult of saving the lives of a woman and | who stopped in his path. Parrish ertook to ride the rounded top of a teel aqueduct which supplies ter for a Pacific coast city. ng stretch of the huge was built on top of ground, then it pped to the ground el and gradually dis- peared beneath the Parrish balanced machine on the few hes of comparative tness on top and start- out to ride down the incline which led m the hill to the val- where the pipe went the ground. \Vith movie cameras cking, the machine making terrific speed hen, as Parrish neared e end of the trip, the man and child walked o view and stopped astonishment as they the machine coming vn the top of the pipe. o startled to move, ‘y stood helpless in the ler’s path. There was » chance to stop, since the slightest hesi- tion meant a slip over the side. Parrish solved the problem by turning front wheel to the side and deliberate- dashed off into space. The machine shed to the ground, breaking both of e rider's legs. TUBERCULOSIS CURE SOUGHT IN CHEMICAL AGENT Search for a chemical substance that in be harmlessly introduced into the dy to destroy the tubercle bacillus is eing conducted by a western physician. le discovered, after injecting tuberculo- s germs into the eins of subjects, at, three to eight eeks later, by far he greater amount as in the lungs. In 1e Majority of cases, ie liver was com- paratively free from lisease, indicating, e believes, that the Trgan contains a chemical that will Crushing Olives in Old-Fashioned Mill, Two Granite ' :| J MIRRORS SPEED PHONE CALLS AND AID LIGHT TESTS Mirrors Adjusted to Save Of- fice Time; One Shows It Phone Calls Are Handled Properly, the Other Reflects Switchboard Lights during Tests Every Two Weeks Reflectors have been utilized in a California department store to save time and trouble in operating a telephone switchboard. One of the mirrors is so adjusted that, by merely glancing at it, the manager can see if calls are being handled efficiently. Another is attached to the ceiling, to facil- itate the testing of lights on the phone panels. This is done by “shorting” the lamps one at a time on a test board be hind the wall. The electrician sees in the mirror if the lights flash properly. BLINDFOLDED HORSE PROPELS OLD-TIME OLIVE-OIL MILL Largely to please its native Italian pa- trons. a large California olive-oil com- pany uses, at one of its mills, an old- fashioned crusher such as has been em ploved for centuries. It consists of two huge granite wheels which are revolved over a circular vat of olives by horsepow er. The animal is blindfolded to keep it from straying frorm throw off the bacilli. Wheels Propelled by Blinded Horse the riag. *

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Protected against Soi'ing. a 1 of Wax Paper Is In- closed tached 2-11 ,Oll S Handy for Wrapping Lunches and Other Uses Time and Money-Saving Tools Flour Is Thoroughly Mixed with Other Dry Ingredients and Sifted Eight Times throug Four Screens in This Simple Shaker For Left-Handed Persons Especially, This Adjustab Paring Knife Simplifies Work, Cuts Slices of Uni.« + Thickness and Also Takes Out Cores in Metal Reel At to Wall, There It Removing Eggs or Other Foods from Frying Pans Is Often a Ticklish Job, but This Broad Bladed Knife Is Easily Slipped Under, and Its Sharp Edge Will Cut Bread; at the Left Is a Double-Comnartment Bucket Formed by Detachable, Semi-cir- cular Lining; Hot Water May Be Poured in One Side and Cold, Clean or Soapy Water in the Other; the Inner Unit Has a Flap to Hold It — in Place and to Aid in Removal Besides Holding Four Spools, This Rack Has a Notch to Cut Thread = f= ————— = : = = ———— Anyone wishing ther iniormat evices des ed in the editor

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Operated Like Scissors, Comb Cleaner with De- tachable Brush Reaches between the Teeth Pudding Cooker Saves Time and Requires No Cloth; Dough Seals the Lid Measurements Are Marked on Black Edge of Tape and Then Rubbed Out Glass Top on Roaster Becomes Platter for Serving Fowl or Other Meats: Round Corners Permit Easy Cleaning Spring Clip on Cake Knife Permits eee Removal of Pieces without Break ( ing or Dropping, and Does Not Paper Pie Plates Instead Soil the Fingers of Tin, Can Be Thrown Away after Baking to Save ashing os _J by addressing Bureau of Inf at 7

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610 BEAUTY PARLOR FOR PET DOGS PREPARES THEM FOR SHOWS Dogs of all ~ given the latest shampoos and kinds are stvles in canine shingles, White and Long-Haired Dogs Need Special Grooming, and Canine Beauty Parlor Is Equipped to Give It foot treatment at a special beauty parlor maintained in connection with a hospital in Boston, Mass. When the pets are to be entered in shows, they receive make-up and powder, if the owner desires. Clip pers and other instruments are included in the equipment of this institution. BULLET-PROOF GLASS RESISTS POWERFUL GERMAN PISTOL tests with bullet-proof glass have shown that the material will not only turn large-sized bul- lets from U. S. army automatic p istols, but also smaller and penetrating missiles from the Mauser [ Recent more weapon ot German make. \ bullet from one oft these revolvers. will penetrate eleven pine boards, while the U.S. automatic is ef fective through eight, but the glass turned the smaller lead, pet nitting it to enter not more than one eighth of an inch in to the surface of the material. \ metal- jacketed bullet was Cracked but Not Broken, a Specimen of Bullet-Proof Glass after Being Struck by Two Lead Missiles POPULAR.MECHANICS turned completely inside out and welded upon the surface of the glass in one of the tests, and a second shot failed to pierce the specimen. The impact caused a series of cracks, but these were not con sidered serious as the target, composed of alternate lavers of glass and a transparent fibrous material, did. not break. A car tridge from a Springfield rifle was also turned back, although the force of the shot pulverized the outer coating of glas and the bullet apparently was vaporized Lavers of the target were separated in circle six inches in diameter around the point of impact, and this space was filled with a thin layer of lead which evidentl\ had been condensed from the vapor. The glass is widely used for windshields, and windows of tellers’ cages and pay cars. SUEZ CANAL BEING ENLARGED TO MEET SHIPPING NEEDS Because steamers are larger than they used to be, engineers are at work on the Suez canal, enlarging the channel so that this important traffic link may better serve the needs of commerce. Originally, the bottom width of the canal, which is 104 miles long, was seventy-two feet and it depth only twenty-six feet. Later, thi increased to thirty-six feet and th: present excavations, when finished, wil insure a depth of not less than forty feet while the bottom width is to be extende: to 300 feet and the minimum surface widt! to 440 feet. Steamers with a draft of thi: tv-three feet will soon be able to use the waterway. A maximum of thirty-one feet is the present capacity. The trip throug! the canal takes si teen hours and about was fifteen ships use every twenty-four hours. Some 4,600 crait are dated accommo yearly, repre senting a net ton nage of more than 22,000,000. Untik« the Panama canal Suez has no loc! The banks are su faced by rocks quar ried near by. \t Port Said, large workshops, which employ more than 1,200 mechanics, are maintained to repait tugs, and oa dredges floating cranes.

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BBITS CURED OF DIZZINESS BY REPEATED SPINNING making them dizzy for brief periods day, rabbits tested by Prof. Knight ip. at Johns Hopkins university, iallv became accustomed to the ment and showed no effects from pinning and cold-water applications e ears by which the dizziness was uced. The experiments indieated t the semicircular canals of the ani- ‘ inner ears, and other organs by the balance is maintained, became usted to the whirling. This sup- ted what already had been found in e case of men tested for admission to ition. It was discovered that candi- tes need not necessarily be rejected their heads swam after being un around in a chair, for it was shown they could become accustomed to unusual motion. According to Prof. unlap, his experiments emphasize the plication of the apparatus which ntrols the equilibrium of the body and iggest lines of further research. ause PORTABLE OFFICE ON CASTERS SAVES STEPS IN SHOP Portable offices that can be rolled to lifferent parts of the floors of a large itomobile shop in San Francisco have proved timesavers to employes and cus- POPULAR MECHANICS oe . 2 a Portable Office in Use; Windows on All Sides Afford View of Shop, and Desk Aids Patrons mers as well. Each is supported on iour casters, has glass windows on all ides, while electric wires are provided with plugs for quick attaching to new ockets when the location of the office is changed. The telephone cable is car ried on a roll which can be unwound when the “cage” is in transit. 641 oa — ee 7@ * a en 4 . we Model of Proposed Rescue Fire Truck with Platforms to Reach to Buildings Extended FIRE TRUCK WITH PLATFORMS TQ AID IN RESCUES To help firemen rescue persons trapped in buildings, an eastern inventor has pre- pared a model of a truck which carries a series of steps on an extension frame and also platforms or landings which may be extended to the windows or other entrances to structures. They serve as bridges, making it unnecessary to lean the ladders against the building and help- ing to prevent falls. The entire appara- tus folds up when lowered, and is raised with power from the motor. BLACK RASPBERRIES ARE WHITE ON FREAK BUSH Having lost the faculty of supplying color, a black-raspberry bush, grown by a Canadian fruit producer, developed white berries. The vine was a seedling and grew to about twice the size of the other bushes. According to a horticultural ex- pert, colorless or white fruit from both the red and the black raspberry is some- times found as a result of plant-breeding work. If vines producing these white berries were isolated from others, it is believed their fruit would continue to breed true to type, reproducing the white or “sport” berries.

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642 POPULAR MECHANICS CLENCHING OF FISTS SHARPENS MENTAL ACTIVITY Many persons knit their brows or clench their fists instinctively when try- Demonstrating the Effect of Clenched Hands on Thought; the Young Woman Grips Handles While Responding to Memory and Other Tests of Mental Alertness ing to concentrate closely. Tests at the University of Chicago show that such actions help the thought processes. There is, apparently, benefit in muscular and mental co-operation. While squeez- ing a pair of handgrips similar to those used in athletic training and examina tions, a young woman student demon- strated that she could pass tests in addi- tion, memorizing and perception much more efficiently than when her muscles were relaxed. The gripping proved es- pecially helpful in tests where great speed, rather than accuracy, was required. The explanation, scientists say, is that when the muscles are tensed, the person is wider awake than when they are relaxed, hence his mental powers are sharpened. NECKLACE OF CAVE-BEAR TEETH CLUE TO LOST ATLANTIS? From one of the deep limestone caves of southwestern France has come a cu- rious relic that points to the mysterious land of Atlantis, the partly mythical con- tinent mentioned by Plato and for which search has been made for centuries. The trinket is a necklace, believed to have adorned some mighty hunter of the Mag- dalenian period some 25,000 years ago. It was brought to this country by Dr. George F. Collie of Beloit college, who has succeeded in piecing it together and tracing the supposed connection it bears to the lost land. The necklace is c posed of four cave-bear teeth, each al: three inches long, a section of the spin of some fish, sixteen inch-long sh« shaped like elephant tusks, and two ot units, similar to small ordinary s| The presence of these shells in the n lace is of special interest to the scient for they suggest a cult that has bee: traced back to Spain where it evident was borrowed, many centuries ago, f1 a land that lay to the west, the supp: location of the lost continent. The s art was also acquired by the Egypt who obtained it from a region of w! there is now no trace, scholars as Dr. Collie holds that it is possible the shell art may have originated in lantis, which is now supposed to be merged in the ocean as a result of a g1 upheaval of nature. DOGS KILLED IN ELECTRIC BOX TO PREVENT SUFFERING When dogs must be killed at the cinnati pound, an electric chair dispat« them quickly and without unneces suffering. The apparatus consists « small compartment and a coil of wire the electric current at the top. This fastened to a collar strapped about + dog’s neck. The charge is turned on :; tomatically when the door is closed. Awaiting the Fatal Electric Current; Charge Is Re- leased When Door Is Closed on Dog

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POPULAR MECHANICS 643 QIXTEEN carloads of educational in- \” ventions have latterly completed ex- ive tours aggregating 70,000 miles id have been viewed with great interest more than 5,000,000 spectators, which licates how admirably Uncle Sam's test strategy is working—he is spread- ng science’s story by getting the people to look even though they will not listen. lo prepare educational exhibits in novel form has been one of the depart- ent of agriculture’s difficulties, and to ike the visualization so vivid and spec- tacular that it will put across its scientific nformation in an understandable and at- tractive manner-has been another. But hy employing experts and inventors to study and produce; by hiring designers, mechanics and artists to make the result- ant models and exhibits, and by display- ing these original masterpieces at_ state, interstate, national and_ international fairs, expositions and congresses through- out the country, the authorities are con- summating remarkable achievements..- The shadow-screen system, operated with a sequence of floodlights, is a recent innovation from Uncle Sam’s workshop which has added a new and outstanding chapter to the history of sight-of-eye edu- cation. If you recall how you have stood outside of the screened window of a darkened room and were. unable to see within, although, when inside the self- same room, you could readily see out, you will understand the working principle according to which the shadow-box ex- hibits are run. Say, for example, that the educational exhibit consists of three sequence pictures which are shifted by SPREADING THE MAGIG STORY OF wc changing lights so rapidly that your eves almost undergo an optical illusion. Two of these pictures will be painted on sets made of window screen. The third pic- ture will appear on the rear wall of the shadow box. By alternately switching on and off the floodlights which illuminate each picture, the effect is similar to the finest motion-picture production, only more spectacular. One of the kingpin shadow boxes por- trays the tale of the neglected campfire which kindles the neighboring forest and results in a million-dollar woodland fire. The first picture shows the abandoned fire left by some hunter or motorist. A heavi- ly wooded slope adjoins the picturesque valley where the few last embers smol der. The next picture explains how a sudden breeze fans the embers into a flame and spreads sparks to dry forest cover, so that a raging fire speeds up the mountain slope, ruining valuable timber and causing wild game to flee before its van. The third scene features despoil ment and desolation with only charred and smoking stumps left to tell the tale of what somebody’s carelessness accom plished. Automatic electric controls govern the shadow-box pictures. The pictures are so nicely dovetailed together that one fades into another. Light and motion are used most skillfully to produce the desired’ effect—an effect which blends to- gether so well that the spectators look around for a projection machine and won der how the startling colors are secured. The effect of motion is obtained by weath ervane-like devices, operated electrically,

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644 to cast moving shadows so as to simulate flames burning or smoke rising. A mechanical cow is another exhibi- tional marvel which the office of exhibits at Washington has originated and per- fected. The effigy is lifelike and true to size. It was made from the bromide en- largement of a Guernsey cow’s photo- graph. This great picture was secured in position on a composition-board frame. An expert artist then colored it. A skilled carpenter sawed the figure from the frame. He mounted it so that it stood alone. In this day and age, when living live stock are displayed in hotel lobbies and assembly halls, a life-size model of a cow does not arouse much interest, no matter where it is shown. Our national representatives pondered, scratched their heads and finally evolved the idea of equipping the cow with visible circulatory and digestive systems, which would simulate the functions of these vital organs in life. One side of the cow’s overcoat Was cut away. A hot-water bottle was camouflaged as a heart. Small rubber tubes were provided as artificial veins and arteries. A carefully adjusted and perfectly timed pump was used to make the bogus heart pulsate regularly and to cause the uniform dilation and Uncle Sam's Artists Painting a Background for One of the Educational Exhibits; Like Stage Scenery, the Pieces Are Constructed for Convenient Shipping When the “Science Show’’ Takes to the Road . POPULAR MECHANICS contraction of the arteries and veins. \ here was something astonishing wl made the crowds stop, stare and study Wherever this mechanical cow was « hibited, it was the center of educatio: interest. Thousands of dairymen and farmers have said after studying the fin exhibit, “This is the first time that I have been able to understand exactly how the cow makes milk from her blood.” terse, understandable language, the act ties of the cow’s vital organs were e plained on poster panels placed direct behind the model. This exhibit put across the object lesson of science in spectacular manner. The model was so instructive and accurate that the Texa agricultural college has made an ex replica which is now used for demonst: tional work before the veterinary clas at that institution. The venerable poultry story of h better breeding and feeding will invar bly be reflected in increased egg yield | also been told in a new language via 1 chanical hens. Here again, invent genius has been capitalized to aid edu tional agriculture. Lifelike models ot | two hens were made. By harnessing el tricity and mechanical motion, the fed: al inventors produced a pair of fo

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POPULAR MECHANICS sages to ers; . a4 4) *-2e What Is a Good Plan to Follow in Constructing a Dairy Barn? A Government Exhibit En- | deavors to An- swer the Ques- tion in a De- tailed Model, Showing _ Prac- tically Every I *.4.4 ee Where Cartoonists’ Brushes Add Empha- sis to Science; Preparing a Special Set Tilustrating Helpful r the Nation’s Farm- Sketches Are Prepared trom Photographs of Actual Scenes, and Charts Im- press the Lessons etalon) al.*.4 tA ut “4 4 ea a Mes-

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646 POPULAR MECHANICS > &-... rad “A Good Picture Is Worth 10,000 Words,” Declares a Chinese Proverb; Believing This, Government Artists Adapt the Most Effective Illustrations Available for the Educational Panels which would crow, flap their wings—and arrangement was such that each egg, lay eggs at regular intervals. One of the deposited, slid through a hinged ape: birds, as shown by her conformation, ture in the nest into a basket below. T! feathers and general appearance, was bet- sensational poultry show was so unusu ter bred than the other. The egg-laying -that everybody who passed would st: apparatus of this hen was geared so that to look. Many interested in egg produ it would deposit twice as many eggs in a_ tion would remain to study and reflec: given period as its mate. Strange to tell, visual exhibits of this ty; A scoring device was placed above each have converted many food producers 1 nest and count was recorded of the num- new methods who would never pay at ber of eggs which each fowl laid. The attention to printed discussions. Scientists and Craftsmen Work Together in This Exhibit Factory in Constructing the Educational Sets for Tours; a Trip Recently Completed Covered 70,000 Miles, Showing to Millions of People

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POPULAR MECHANICS A puzzle latterly confronted Uncle m’s exhibit makers. They needed some tificial grass to use in a steer-feeding monstration. They hunted high and but found that artificial grass was pparently as scarce as bathing suits at North Pole. Where do you think ey finally found what they were aiter? an undertaking establishment. The iss mats which the undertaker places er the newly filled grave were just the hing. These mats are made of raffia— imported palm-tree product — which in be dyed any color and is fastened se- irely to a burlap base. Time was when the exhibits which you iw at fairs, shows and expositions, con- sted almost entirely of photographs and splays of grains, grasses, fruits, farm roducts, and the like. Recent!v, Uncle Sam has instituted remarkable reforms. He has hired some of the count-y’s best talent to originate and perfect scientific shows which will arouse universal inter- est. Congress has supported the revised rogram admirably. Special workshops, studios and warehouses are now used exclusively for these displays. Many of these exhibits consist of nged panels upon which are painted the figures of animals, men and farm scenes. \ll these panels are made of composition hoard, which is light, durable and easy to handle. The arrangement is such that the same panels can be used year after year bv merely changing the pictures or models. STAPLER FOR ROLLER SHADES SAVES TIME AND WASTE Shade cloth is attached quickly neatly to rollers with pler that has a curved extension on one side to hold it on the center. Staples are insert- ed by pressing down on a plunger bar, and they are connected in a strip of seventy-seven placed in a maga- zine which can be refilled in three seconds. and the aid of a sta- There is little danger of tearing or cutting the cloth with this stapler; it is not necessary to hold the roller with the hands while tacking, and the outfit weighs but two pounds. @ From twenty-five to twenty-eight miles an hour is the average speed of most oi the varieties of smaller birds. 647 REPRODUCER OF SOUND WAVES PRESERVES TONE QUALITY For recording and reproducing sound, an apparatus developed by an engineer of the General Electric company is reported Preserving the Voice on Record- Soa ing and Reprodu- * —____ ing Apparatus eee to be greatly superior to the radio or phonograph. Tone quality is preserved and a wide musical range can be regis- tered, it is said. The process used is somewhat like that employed with talking motion pictures, the voice or other sound being caught on a film, then reproduced by the action of sensitive cells. PER CENT OF CARBON IN COAL CLUE TO OIL DEPOSITS The ratio of fixed carbon to the total combustible matter in coal is an index as to the probable presence and depth of oil or gas accumulations, according to G. F. Moulton, of the Illinois geological sur- vey. Coals mined in that state were found to have a fixed-carbon content varying from forty-nine to sixty-three per cent of the total combustible matter, while most of the oil comes from areas in which the carbon ratio lies between fifty-fourand fifty-seven per cent. The reason for this relationship is that heat and pressure con- ditions which affect the accumulation of oil, change the composition of the coal. In areas where the carbon ratios are above sixty per cent, the oil and gas possibili- ties are poor, whale the lower the ratios, the greater the chance of striking oil.

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648 POPULAR MECHANICS NAMING BUGS AND BEETLES air produces congestion and swelling WOMAN’S ODD JOB the mucous membrane which beco: covered with a thick secretion and affo: To the lay mind a beetle is a beetle, but a weak spot for germs to attack. In c to the scientist its species is extremely im- air, this membrane remains taut and w: portant for study and classifica- moistened. Then, in a poorly v: tion. Identifying and naming in- tilated room, cold currents of sects from all over the world is jf are likely to strike the feet while t head is exposed to t warm, polluted upper mosphere. This is ju the reverse of what considered the ideal c: dition for health, “ce: breezes blowing arou the head, the radiant h: of the sun and a wai ground to stand o1 Exposure alone will 1 cause colds in healthy dividuals, the doctors d clare. Arctic explore: fishermen, and other who remain out of doo: for long hours in storn Miss Armstrong and Sample Case of Beetle Specimens at Smithsonian Insti- cold - eather, Omen scet tution; Insects Must Be Correctly Named and Classified immune trom -these d orders. Irritation of t! the difficult and unusual task of Miss mucous membrane of the respiratory pa Elenora T.eArmstrong of the Smithsonian sages by dusts and chemicals is also Institution. If a specimen is sent in as a common cause of colds. new one, it is part of her job to examine / it carefully and search records to see if the ' -beetle or bug really is a new find, and if POLICE WEAR COLORED LIGHTS it is, she devises a suitable name which FOR NIGHT TRAFFIC WORK will meet the needs of scientific classifica- tions and accurately describe the subject. - Human “lighthouses” will aid night faring motorists and pedestrians in Ne York under the plan of John A. Harris BAD VENTILATION FOUND TO BE special deputy police commissioner. H COMMONEST CAUSE OF COLDS has ordered a special equipment of gree: red and yellow lights, operated | push buttons and worn on t! traffic policeman’s chest, an amplification of the signal tower's servi to. travelers. The colors mean “G: “Stop.” and “Get Ready” as in th stationary beacon and since the p: liceman usual! | stands in a conspi uous place, there | less chance that h lights will be ol scured. The pla also will save in stalling signal post : at intersection ed as the common- ten — where a traffi est of all the causes, guide is eede a - : ' — Turning Policemen into Traffic Towers; Set of Colored- guide ss gl as warm stagnant Light Signals for Directing Night Travelers only on occasion To find better preventive methods, doctors in re- cent years have been studying the common cold more caretully than ever, and two authorities have summarized the supposed causes of this affliction under five headings: chills and drafts, con- ditions of the weather, irritation of the membrane on the breathing apparatus, infection and bad ventilation. The last is regard- P. if

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How to Improve Your Set By F. L. BRITTIN N? radio receiver is perfect; some ap- a proach perfection, but the large majority fall far short of the mark. The ideal receiver is still in the dim future: no science stands still and radio least of ill. It is yet in the experimental stage in many respects, although the progress made in the last few years has been phe- nomenal. No matter what type your set s, many simple additions or corrections an be made that will improve the tone quality, selectivity, range and volume. hese improvements, however, need not e of an expensive nature, if vou study our own set and locate the imperfections. \ word of advice is pertinent here. Do not listen to the say-so of every “ex- pert” who comes along; his experience ay have been with an entirely different tvpe of set, and the remedy suitable for one circuit may be entirely wrong for the same symptoms in another. There are several general rules to

and tubes. We will not go into these general details as they are taken as a mat- ter of course. The efficiency of any set is limited by the surrounding conditions, including atmospheric disturbances and interference from all sorts of electrically operated devices and power lines. These disturbing elements all work against good reception, no matter how excellent the set may be. The set itself, on the other hand, must not contain elements that add to the difficulties to be overcome. Selecti%e and easier tuning is an impor- tant factor in crowded cities, as the 10- kilocycle separation of wavelengths al- lotted by the government to the broad casting stations is not sufficient to make tuning easy in locations where several Interfet similar + = a 3 — aes = Jag ay y 4 L stations are grouped together. ence between stations having i“? mee A ‘4

follow for best results that ap- ply to all sets, such as well- constructed aerials, efficient grounds, and good batteries SMALL BOLT; | ee IY = | } < eee

— x } 649

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65 POPULAR MECHANICS wavelengths also often defies separation, although the stations may be hundreds of miles apart. Radio designers and manu- facturers are striving to remedy the con- dition, and good progress has been made. Straight-line-frequency condensers, when used with the proper coils, have made possible a wider separation of stations over the dial. The crowding of the low- wavelength stations on the lower half of the ordinary dial with the common type of condenser is illustratedin Fig.1. Many who have sets equipped with this type of straight-line wavelength condensers two trains move in such a way that, while one moves a pointer at a regular rate over the graduated scale of the dial, the other train rotates the condenser This latter gear train works in such a way that, at the lower readings, the con- denser moves faster than the pointer, causing the stations at the crowded low wavelengths to be separated on the scale and bringing the stations of higher wave- lengths closer together. A homemade logging plate is shown in Fig. 3, which can be placed behind the or- dinary dial and is a simple aid in tuning.

do not care to discard them, ar@l the set, A disk of aluminum is cut in the form y- — 2 a. - oe i il > ae CON DJENSERS —=+MIDGET M ae Be 31 SL

Fic.5 } (< MIDGET. é Fic.6 Lf:

oles

»- MIDGET

BY

| ley E

mee

even if this is desired, may be so designed that it is not practical to install the new straight-line frequency type. Several manufacturers, therefore, are bringing out special dials that will make the com- mon condenser approach the same re- sult (see Fig. 2). This is accomplished by means of an ingenious arrangement of two gear trains, or a similar mechanism, within the tront plate of the dial. The

shown, and is fastened to the panel by means of a locknut or screws. The disk should be large enough to extend above the dial when in position, giving space for writing in the call letters of the various broadcasting stations. Tuning is often made difficult by body capacity; a sta- tion is tuned in and when the hand is withdrawn from the dial it is gone. There are several ways of correcting this de-

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fect; a simple method is shown in Fig. 4, 649 POPULAR MECHANICS 651 resistance can be varied from zero to 500,000 ohms. When connected in the in a case (a very common one) where the live shaft of the condenser caused the trouble. A wooden spool was used to form a collar for a hard-rubber extension rod, and the condenser was remounted, on the bakelite subpanel several inches back of the front panel, with the result that the hand capacity disap- peared. Other methods of cor- recting hand capacity are ground- ing the rotor plates of the con- denser, and shielding the back of the instrument panel. One of the simplest ways of im- proving the set is the intelligent use of a midget, or balancing, con- denser; there are a number of these little condensers now on the market similar to the one shown in the inset illustration under Fig. 7. They are very useful for vernier action, for neutralizing and for capacity regenerative feedback. The capacity of these condensers is very low, and the construction is % along low-loss lines. Fig. 5 shows # one of these little condensers used ~ as a vernier on a large condenser; Fig. 6 shows an ideal method for obtaining vernier control of re- generation by tuning the tickler coil of the three-circuit tuner with the midget condenser. For those « who have tuned r.f. sets not neu- tralized, or have old-type inefficient neu- tralizing condensers, the midget is a val- uable addition to the set; Fig. 7 shows the usual method of neutralizing the tube capacities. Those who would like to experiment with capacity antenna coupling, and the use of a vernier across the grid-tuning condenser, will find a wiring diagram in Fig. 8. Adding regeneration to the loop on tuned r.f. sets and superheterodyne receivers means better distant reception, and will appeal to all DX fans; Fig. 9 shows the method and the midget con- denser turns the trick. Volume control is a point sometimes overlooked in these days of fewer jacks, and the tendency to eliminate as many controls as possible. There are two very easy methods of controlling volume and tone quality by the addition of simple and inexpensive instruments to the set, as shown in Figs. 10 and 12. The instru- ment shown in the insert in Fig. 10 is a non-inductive variable resistance of the same general constructon and appear- ance as a potentiometer; this instru- ment is known as a modulator, and its audio-amplifying circuit, as shown in the diagram, the modulator gives noiseless adjustment to any desired tone volume, from a whijsper to maximum strength, greatly improving the quality of repro- —— The method \ BY-PASS COND. 170 4 MED. A-BATTERY Fig.13 ANTENNA TO AERIAL POST , shown in Fig. 12 is similar, but the in- strument is here connected across the sec- ondary of the last r.f. transformer, and consists of a variable resistance ranging from 10,000 to 120,000 ohms: it can also be used in resistance-coupled amplifiers. If your receiver does not cover the broadcast wave bands as well as it should, the addition of a variometer in the aerial circuit, as shown in Fig. 11, will often give the desired result. If the set is noisy, this can often be remedied by the use of a by-pass condenser across the en- tire B-battery, as shown in Fig. 13. This condenser should be as nearly perfect as possible, and the larger the better; if de- fective, it will only make matters Worse. Good sets often give poor results due to an inefficient ground. This is especially true in dry, sandy localities; the counter- poise ground shown in Fig. 14 will be found a decided improvement and costs very little. It is an exact counterpart of the aerial above it and the lead-in is taken to the ground post on the set. This type of. capacity ground should be in general use, as, in most cases, it is more efficient than the ground available

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APD cui BASE TOA AUS 5 aa le ea

A- INSTRUMENT PANEL ATTERY SPEAKER be a B-BATTERY IN REAR

DROP LEAF FOR CHARGER INSTRUMENT PANEL

PHONES, LOGBOOK, ETC. |

1"SQ. CORNER \j<—- SUPPORT D

AS “™s A

DETAIL OF LEG BRACES UPPER END OF LEGS nat L SAAR CESUTAT IT AY 2 wana hase +) Various Details of Design of the Radio Console Cabinet, and Drawing of the Completed Cabinet, Showing Decorative Scheme

652

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How to Build a Radio Console By HERBERT C. McKAY ADIO is universal, but its develop- ment has been largely that of effi- ciency. Appearances have been left to care for themselves with the result that today the radio set in most American homes means a small square cabinet, A. 8 and C-batteries standing upon the table near by, a loud speaker on top of the set, while logbook, phones and similar arti- cles decorate the landscape. The home mechanic who is even moderately skill- ful in the use of tools, however, may as- semble his own set and inclose it in a abinet, at a total cost of less than $100, even in the case of the multi-tube sets. The dimensions and even the details of design of the cabinet will vary with the different sets, so no exact measurements will be given. The drawings and text will vive the reader sufficient information to enable him to build the cabinet which suits his particular set. The set from which the drawings were taken was built to accommodate an 8 by this paper. In this case, the edges of the designs are painted black and the whol¢ glued to the panels. A coat of varnish completes the work. These methods are makeshifts, however. For a really good job, the panels should be finished with cut-out designs in relief. For this work a thin veneer is obtained. Spanish mahog- any from a cigar-box factory will serve beautifully. The designs are cut out, and laid out upon the panels before the cabinet frame is assembled. Then the legs are recessed deeply enough to com- pensate for this added thickness. In this case, the designs will appear as relief carving, with the contrasting tone to add attractiveness. The slight extra work will repay the builder well. The first step is to construct the frame- work. The legs are cut from material 3-in. square. The two front legs may dif- fer from the rear ones, depending upon the finfsh of the rear of the cabinet. If it is to be a four-square job, completely 28-in. panel. The instrument inclosed _ finished, all legs will be made as shown was a five-tube, -. = iliaiataiiaaaainan for the _ front tuned radio-fre- = legs, while, if quency set. The the rear is to batteries used a4 i, have a rough were one 6-volt, finish, the rear 100 -amp. - hour legs will be storage battery, made as shown a Tungar charg- a in the lower fig- er, and two 45- volt B-batteries. The latter were of the upright, heavy-duty type. The speaker was B- INSTRUMENT 0 ‘ COMPARTMENT siieaas! ure, detailing the legs. The differ- ' ence between the two is only that, in the lat- ter case, the legs 1 ! ' i -~ F Ni of the paper- BASE eR’ K'S)L’ are not recessed cone type. As KJ}! upon the rear this type of = re are Site side for the pan- speaker is not as .~ se PHONE |AND LOG COMPARTMENT | | a eling. The per- common as the BF gee he r 4 4 spective shows horn type, two — _ Hd the construction extra drawings Ss | SS. S clearly. First the have been in- 4+ t-- SILL Na i '4-in. recess, A, cluded to show ‘ pe si is shown. The how to adapt +-LEG | paneling sits the horn to the SECTIONAL VIEW lesion flush in this re- cabinet. cess. Above this The full-page cut shows the front of the finished cabinet. The two-tone effect adds greatly to the homemade set. This finish may be secured in different ways. For example, the cabinet may be stained mahogany, the design then painted in with enamel, and the whole varnished. Another way is to stain the cabinet, then buy wood-grained paper such as is used by decorators and cut the design from are shown the recesses for the two 1 by 3-in. sills, at B. A portion, C, of the leg post is left to support these sills, while above is a l-in. square of the original post, D, which supports the corners of the end cabinets. Another detail shows the construction of the leg braces. Short crossbraces con- nect the two pairs of end legs, while a single center brace extends from one end 653

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654 POPULAR MECHANICS 'DISK-TYPE OFM SPEAKER IN HORNE COMPARTMENT. DOOR WITH GRILL FOR GOOSENECK HORN to the other, as shown. By care- ful mortising and the use of both screws and glue, this con- struction will prove to be adequate. The frame is now assembled. The braces will support the legs at the bottom, while the sills will support the top. These sills may be 1 by 2, 1 by 3, 1 by 4-in., or a combina- tion, depending upon the size of the cabi- net and the material used. The original cabinet had 1 by 3-in. sills of oak. The next step is to insert two extra braces, as shown in the detail of the frame ready for flooring. One is a center sill, and the other is an added sill across the battery compartment to support the ex- tra weight at that end. This view shows paneling in place for a rough-finish rear, while the drawing below shows the panel- ing for a finished rear The frame is now floored with ceiling material, or regular flooring. This is cut flush with the sills, so that the paneling will cover the edges of the flooring boards. The next step is the framing of the end GOOSENECK HORN IN POSITION cabinets, as shown in the drawing of the frame assembly. A and B are the corner supports. JT of these in each side cabinet will be the continuation of the leg. The other two posts are 1 by l-in., set upon the floor. In the original cabinet these were set 10-in., outside to outside, so that the application of the '4-in. plywood paneling make these end cabinets 11 in. wide, out side measurement. A stronger construc tion is obtained by notching the floor and extending these end supports to the sills as shown. Two pieces of 1 by 2-in. stock are then cut, as shown at F, and set upon the end posts. Then two pieces, C, are cut and placed for the top-side supports. Piece 1 by l-in., as shown at G, are set between the posts upon the floor. Now braces, E, are set upon the inner side of the end cabinets for added support This completes the framing of the side cabinets. The next step is to apply the panels on the inside of these cabinets. This is necessary, as the framing of the radio cabinet proper is secured to this paneling. The frame-assembly drawing shows the completed framework, except that these two panels have been omitted for the sake of simplicity. It is to be assumed that these panels are in place between —— el —

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a POPULAR MECHANICS the framing of the end cabinets and the radio cabinet itself. End supports, M., are cut 4 in. long, and beams, L, secured to them. Upon these, the radio-cabinet floor, K, is laid. This should be one piece in front of the panel, in order that the best finish may be obtained. Referring now to both sectional view and frame-assembly drawing, bottom beam J! is laid in. Then lower beams, K! and L!, are laid in place and secured. Next, uprights, H, O and P, are secured to the paneling of the side cabinets. Upon these are laid the upper beams, J, K, and L, is shown. Then cross beams, R and §S, are secured to the side panel, as are the cor- responding lower cross beams, R! and S!. lhe panel supports, T, are now placed in position. Uprights are not needed here, although they may be added if de- ired. To these are secured the ‘panel- frame members, U. These members should be the thickness of the panel and 1 in. wide. These form a support and frame C,E,AND F,1K2" STOCK COMPLETE FRAME ASSEMBLY 655 radio compartment is ready for covering. This cover may be hinged in the middle, which gives a more symmetrical appear- ance, or it may be hinged at the upper beam, K, for easier access to the instru- ment compartment. The front door, which is hinged at the bottom, may be left to the last step. The paneling is now applied. cabinet doors may be hinged as_ best pleases the constructor. In the original cabinet the end doors, the square ones, are hinged at the top. As they are sel- dom opened, this makes the natural po sition the closed one. Also, in the origi- nal, the front panels of these compart- ments were fixed in place. This was due to the fact that the non-directional disk speaker was employed. For the horn, it will be necessary to make a speaker panel in the front of the speaker com- partment, and this compartment must have a door to open this panel to the room. This door may be hinged at the inside, or it may be hinged to the larger door. In this case, opening the larger door will also lift the front door and expose the whole compartment. In the original cabinet, the 18-in. disk speaker occupies a place as shown in the perspective detail. It practically fills the compartment. This cabinet is placed so that the speaker compartment faces the longer open side of the room. In The end- FRONT LEG, 2 REQUIRED for the panel, giving a more finished et- fect than if the panel completely filled the cabinet front. It may be said here that the sloping panel is used only for the improved appearance. The upright panel is just as easily added. The parti- tion between the instrument compart- ment and the battery compartment is placed against uprights, O, and beams, K and K!. Now the top support, Q, is attached to the cabinet panel, and the t 2 he det ls LI 2 > REAR LEG, 2 REQUIRED DETAIL OF LEGS

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656 POPULAR the door of this compartment a design was fret-sawed, as shown. This was lined with brown silk. Thus, the repro- duction from the hidden speaker was quite satisfactory. In case a horn is used hi | _ EXTRA oe | BRACES “= —-— CENTER SILL, se BATTERY COMPARTMENT =| FRAME READY FOR FLOORING J Tht t r B- BATTERY | ARTITION * x A-BAT. UPPER &LOWER BEAM? INSTRUMENTS GURGER || |Wpper BEAM PEAKER LOWER BEAM~, bt ! PANELLING FOR FINISHED REAR it will be placed as shown in the lower drawing, This requires a small horn. A supplementary panel, as shown in the full- page drawing, is placed just behind the front door. Thus, by opening this door, the horn is directed into the room, a nec- essary arrangement, as the horn has posi- tive directional qualities. Certain adaptations will be necessary for different sets. For example, with a large gooseneck horn, the end compart- ments could be made smaller to take the A-battery in one end and the charger in the other, with the horn exposed on top of the cabinet. If a loop is used, it may be mounted on the inside of one of the end doors. If desired, a wooden horn may be built to conform to an end cabinet, and the unit attached. In fact, this design may be regarded as basic, and any neces- sary change is easily made by merely altering the dimensions of the component parts. It will be noticed that when the cabinet is completed there are no projections. The corners from floor to top are un- broken lines. The paneling is inset to make this possible. The result is that the work_is made far easier than it. would be if more complicated cabinetmaking methods were employed, yet the result has a certain severity of outline that is very attractive. The finish may be of any kind, but if MECHANICS no other finish is especially desired, the fret-sawed two-tone effect cannot be sur- passed for simple yet elegant appearance. Dust between Condenser Plates Causes Volume and Selectivity Loss In many cases of trouble with radio-re- ceiving sets the cause is some trivial thing that escapes the eye. Dust between con- denser plates is one of these; sets will be- come noisy, lose volume and selectivity under such conditions, because dust par- ticles form sharp points on the surface of the conductors permitting the energy to leak across to the other plate. Dust- proof condensers are now available, some completely shielded in a metal case, others provided with a dust-proof transparent shield of celluloid. If the condensers are not covered in such a manner, it is neces- sary to clean the plates with a pipe cleaner or similar brush. Make it a rule to do this at intervals, even if the plates look clean. Using Old Binding Posts As every fan knows, the batteries re- quired for the newer-type radio sets offer a difficulty in making the connections to the contacts rigid. The terminals on the usual dry cells are not capable of holding more than one 7 COPPER WIRE lead with good BATTERY contact. This is especially true if the proper - size battery leads of No. 14 insu- lated wire are used. The up- per illustration shows a simple way of getting around this dif- ficulty. Take a short length of No. 14 busbar wire and bend the ends to hold a stand- ard binding post securely. Solder this shank of the post to the end of the wire to make an absolute contact. Compress the battery terminal so that the special connection can be slipped under the pro- jecting hook part of the battery terminal. If this is provided with knurled nuts, the busbar wire carrying the binding posts should be longer, with a loop formed at the center to slip over the terminal post.

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a he two binding posts provide an easy ethod for making quick changes in the ttery connections, and do not put an nnecessary strain on the terminals. POPULAR MECHANICS 657 Simple Battery Changes for New Power Tubes The installation of the new power tubes \nother handy use for old binding posts seems to offer some difficulties to the illustrated below; the head is cut from average experimenter, he machine screw furnished with the inding posts, and this screw is then used a connection for the two posts, making n ideal connector for placing vo or more sets of headphones FLEXIBLE LEADS, JF ce ! y n series. DISCONNECT i massed WHEN USING _ SE STANDARD H ii Homemade Gang Plug and TUBE yi / Socket Save Tubes Radio experimenters who fre- quently test out new circuits or + ss al ipparatus are worried by the 135-V risk of wrong battery connec- ees tions, which may be overlooked DISCONNECT WHEN particularly in setS UsiING STANDARD TUBE ) B B At AMP. _iODET. i” A- c- n the usual impatience to test the new devices. Simple Battery Changes for Cutting B-BATTERY One experimenter has made his’ In and Out the New Power Tube jj battery connections fool-proof by ilways using a tube socket for the battery terminals in the receiver, then connecting the leads from the batteries to a wooden plug made to fit the tube socket. The socket is of the common type with extra clips mounted on the base. The six spring clips take care of the A, B and C-battery connections. An ordinary four-prong socket can be used if the set requires only four battery connections such as A+, B—, B-22 and B-90. The plug is drilled to take the required number of machine screws, which act as contacts, and the various battery leads are then soldered to the ends of these screws. The wood base is hollowed slightly for the plug, and a small section is cut away for the leads which are ‘twisted in cable form. Homemade Battery Plug Prevents Wrong Connections Left, Underside of Socket, Showing Extra Spring Clips A pin in the side of the plug prevents wrong insertion of the plug in the socket, and the experimenter is always sure that all batteries are correctly connected. ordinarily equipped A-GATTERY with only one stage of a.f. amplification, and those which have two stages but will operate the loud speaker only on the last stage, and even then with too little vol- ume to suit the operator on distant sta- tions. On the other hand, the volume on the last stage may be too great for locals, and some simple means for cutting out the power tube when not required is desirable. All this can be handled nicely by the ar- rangement shown in the diagram. A socket of the new standard UX-type, which will take the 3-volt and 5-volt tubes as well as the common type, is provided. Inspection of the diagram will reveal a simple but effective method of changing the ordinary C-battery connections, as well as the necessary shift from 135 to 90 volts of B-battery suitable for cutting out the power tube and replacing it with the standard-capacity tube for local recep- tion on the loud speaker. The diagram shows the 22%-volt C-battery used with the 3-volt power tube; if the 5-volt tubes are used with the 135-volt B-battervy, it is necessary to have a 9-volt C-batterv in- stead of the 22'4-volt unit. The writer estimates that the change from power to standard-capacity tubes can be made with this arrangement in less than three minutes. The power tubes are fine for distant reception but for local work the standard tube will give better quality of tone. The diagram given is suitable for the small-tube super set now in general use, where’ one stage of audio amplifica- tion is used.—L. H. Georger, Buffalo, N.Y.

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— A Cheap and Efficient Dry-Cell Tube Set By JOSEPH SHOGREN ‘Tas set is especially designed for the beginner who is ready for the step from the crystal receiver to the tube. The layout is arranged so that the experimen- ter can try out various types of detector circuits, and use parts from the old crystal set if desired. There are no panels to drill, and the set is extremely simple to build. The coils are homemade, and the coil mounting is so constructed that coils of various sizes can be quickly placed in the circuit. The set need not cost over $9.50, including the tube and batteries AERIAL-. ‘ the coils can be varied, if flexible leads a: used, by sliding the coils along the ro Selectivity can be further obtained by u ing a larger primary coil, tapping off t! coil to an inductance switch; a .0005-mf. variable condenser in series with the aeria lead will also provide closer tuning, if t! set is used near powerful stations. To make the form for winding the coil: inscribe a circle, 2% in. in diameter, on block of wood, point off thirteen holes : equal distances around this circle, and with a hand drill sink holes for thirteen wooden pegs or nails, 2% in. long. li nails are used, cut off the heads so that the coils can be with drawn: from the form. Wind the coils with No. 22 d.c.c. mag net wire, leaving a starting end 4 or 5 in. long, and winding in and out over two pegs and un der two pegs; mark one of the Above, Diagram of Connections of the One-Tube Receiver; Below, Method of Winding the Coils but not the phones. A good pair of 2,000- ohm phones can be obtained for $3.50, however. Receivers of this type are not toys, but really efficient instruments, bringing in stations 500 to 600 miles away during silent night in Chicago, with good clear reception. The set is fairly selective, as the coupling between 658 pegs and count each turn as tiis peg is passed. Fifty to sixt) turns are wound on the second- ary coil, and from 16 to 40 on the pri mary. Make up several primary coils for experimenting. When the coil is wound, remove it carefully from the form, and, with light string or heavy thread, sew in and out through the holes left by the pegs, tying the ends of the thread so that the coil will retain its compact shape. Copyright,1926, Popular Mechanics Magazine es

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POPULAR M The detail of the wood rights for the coil sup- rt and rod are given the diagram. The for the rod should large enough so that can be slipped out hen the coils are iged. The wood base- ird is 46 by 8 by 9 in., | four rubber feet are sed to elevate it above e table. The instru- ‘nts should be ar- ged on the board as wn in the wiring dia- es ram; the variable con- enser is mounted on o brass’ brackets, hich .are drilled ™% in. rom the top to take the ondenser-mounting and at the base for two wood rew It should be of the type having tra vernier plates, if possible, although e non-vernier type can be used if the her not available. The rheostat is i the 25 or 30-ohm type suitable for the X\-199 or CX-299 tube, and is mounted a bakelite or wood mounting, as vn. This mounting bracket 2 in. and 2% in. high; the gridleak and rid condenser are mounted directly be- hind the rheostat, the type shown being combined unit with a variable leak. A Lewes, >. is 1) O’ is 1de ie % WOOD ROD, 544 LONG . ss naan 5% 60-TURN SEC. COIL Complete Set, Vigx ex3'e ;UX-I99 TUBE ECHANICS 6L9 Showing Batteries and Phones Connected .00025-mid. condenser meg. gridleak can be used, that one side of the grid condenser and gridleak goes to one side of the variable condenser and also to the secondary coil; the other the leak and grid con- denser goes to the grid post on the tube socket. The tube socket of the type suitable for the new 3-volt tubes, and will also take the new 5-volt UX-201A and CX-301A, if the builder wishes to use one of these. In this case, it will be nec- essary to employ an A-battery of four No. 6 dry cells connected in series, while the B- battery remains the same and no other change necessary. The binding posts for the ground, aerial and phones are mounted on the base in the positions shown; the \ and B-battery termi- nals, arranged at the edge of the gp anger are Fahnestock clips and are fastened with short \\ ood SCTeWs. The set can and 2- however. Note separate side of is | is tl 2 REQUIRED be wired I6TURN PRI. COIL 25-OHM M AIF A-BATTERY RHEOSTAT yes d.c.c wire from the coils; -spaghetti tubing can be used on this wire where necessary to pre- vent possible shorts. A schematic diagram of the wiring is given, but with the No. 22 left over OY pb PHONES lack Fis.2 Schematic Diagram of the Circuit 4 aifi{ifi 22'-VOLT B-BATTERY Construction Details of the Coil! Supports and Condenser Brackets; if the picture diagram is followed and each wire run exactly as shown, Below, good results are sure to

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660 POPULAR follow. The dotted lines indicate the wires carried under the baseboard. Connect the A and B-batteries before placing the tube in the socket; turning the rheostat to the off point switches the set off. The experimenter will find that this simple layout will lend itself nicely to such hookups as the reflex, three-cir- cuit regenerative and ultra-audion. A MECHANICS one-wire outdoor aerial, 75 to 100 ft. long, will give the best results. Blueprints of the wiring diagram, and battery connections for using either type of tube may be obtained from the Radio department, Popular Mechanics Maga zine, 200 E. Ontario Street, Chicago. In close 15 cents to cover postage and pack- ing. Specify blueprint No. 107. 1 wood baseboard, 5-16 by 8 by 9 in. 2 pieces wood, % by 4% by 3% in. % Ib. d.c.c. magnet wire. wood rod, % by 534 in. 7-in. brass strip, 1-16 by ™% in. vernier variable condenser, .0005 mfd., and dial. rheostat, 25 or 30 ohms. tube socket, new, for UX-199 or CX-299 tube. binding posts. Fahnestock clips. grid condenser, .00025 mfd., and 2-meg leak (for combination). me ee et MATERIAL LIST UX-199 or CX-299 tube. No. 6 dry cells. 22%-volt B-battery unit. ae brass machine screws, 6-32, ™% in. ong. round-head brass wood screws, % in. long. round-head brass wood screws, 3% in. long. round-head brass wood screws, ™% in. long. 2-ft. length of black-spaghetti tubing. rubber feet. set headphones, 2,000 ohms. ground clamp. Neh eS he ho How to Overcome Body Capacity Every radio fan has heard of body ca- pacity until he is tired of it, and it is safe to say that nearly all of them have had their own troubles with it. Be that as it may, most of them would have better luck if they had a better understanding of what it really is. What is this mysterious force that often upsets the finest tuning with unruly squeals, and what is the best way to overcome its effects? Body capacity, or hand capacity, is the term applied to the property of the human body which makes it behave as an electric condenser. The body is not a good con- denser. Compared with the variable con- densers in a receiving set it has an ex- tremely small capacity. The trouble is that even an extremely small variation in either capacity or inductance of a set can throw fine tuning out of adjustment. Each time the operator’s hand takes hold or lets go of a knob in the process of tuning, the capacity of the set varies slightly, because some of the body capacity is communi- cated to the set while the hand is in con- tact with it. Then you know too well what happens. A very fine adjustment of the total capacity of a set can be obtained with modern vernier knobs for rotating the parts of the condensers, which supply practically all of the capacity of the cir- cuit. In the same way a very fine adjust- ment of the total inductance is obtained by rotating the parts of the coils which sup- ply nearly all of the inductance in the cir- cuit. Thus these two elements in the set itself can be very closely controlled. Body capacity, while small enough in itself, is quite beyond control. That is why, if it is allowed to act on the set at all, it is likely to upset the whole scheme. Some radio enthusiasts who can build anything from a pocket crystal set to a superheterodyne do not know just why this adjustment of capacity and inductance values is so important in its effect on re- ception. The reason, technically, is that when these values are properly related to each other for any given wavelength, the total equivalent resistance of the circuit is reduced to the minimum. As the voltage supplied to the set by batteries or lighting circuit is constant, minimum resistance means maximum current. With the maxi- mum current flowing through the set, the point of resonance is reached—the point at which signals are strongest. Attempts have been made to eliminate body capacity by various methods, but the most effective has been the protection of the panel, or, in some cases, of individual parts of the set, with a metallic shield. The shield, until recently, had to be applied either by the user or by the dealer, but an anti-capacity panel of hard rubber is now being made with a shield vulcanized in place, and this is very effective. Shield- ing, while decreasing the effects of body capacity, does not detract in any way from the quality or volume of the tone. In order to make shielding thoroughly effective, care must be used in making con- nections in the circuit. - The grid and plate terminals are most sensitive to bodv-ca- pacity effects. Keep the parts of the coil or apparatus to which the grid or plate is

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POPULAR MECHANICS 661 onnected as far as possible from the panel. he filament circuit must be properly rounded. When variable condensers are iounted on the panel, connect the rotor nlates to the ground or filament side. there are variable condensers on the arket with end rotor plates, which can therefore be termed self-shielding. With a eries condenser in the antenna, the rotor plates should be connected to the antenna; with the condenser in the ground circuit, the rotor plates should be connected to the grounded side. A condenser across the secondary should have the stationary plates connected to the grid. With a variometer in the secondary cir- cuit, the stator end is connected to the grid; in the plate circuit, the stator end is connected to the plate. Where a tickler is at the end of an inductance, which is the case with many variocouplers, the end of the coil farthest from the tickler end should be connected to the grid. In locating the sockets, keep the grid and plate terminals farthest from the panel, and place the filament leads toward it. It is helpful also to shunt the phones with a fixed condenser of .001 or .002 mfd. capacity, or if amplification is used, to connect a fixed condenser across the plate terminal of the detector tube and the negative side of the B-battery. Picture-Molding Clamp for Indoor Aerial An insulated support for indoor aerials that clamps on the picture molding has made its appearance on the market. It consists of a tubular porcelain insulator mounted on a wire clamp. This can be firmly attached to any standard picture molding, without the use of nails or screws. | he-around-the-room aerial has almost the capacity of the outside aerial for volume, and the selectivity will not be impaired by its use International Radio Week Tests Popular Mechanics Magazine is inter- ested in hearing from readers that have huilt sets described in the Magazine who were successful in bringing in distant stations during the International Radio week tests, Jan. 24-30, this year. Please state the type of set used and send a copy ot your log. Combined Gridleak and Condenser Grid condensers are usually furnished with clips for holding the gridleak. A compact unit, which combines both the Combined Grid Condenser and Leak Assembled, and Disassembled to Show Parts and Method of Winding condenser and leak, is now on the mar- ket, however. It consists of a pair of wires, coated with a special insulating material and wound in parallel, in a single layer, upon a bakelite bobbin. One wire is connected to one cap and the other wire to the opposite cap, as indicated in the drawing. Each wire has one open end and one end connected to a terminal, thus forming two plates of a condenser. The method of winding is claimed to insure that the spacing between them can vary only a trifle, which gives extreme uni- formity. The gridleak is suspended in the center of the bakelite bobbin on which the wires are wound, and the ends of the leak are connected to the caps as the wires. This completes the arrangement and the caps are then screwed down tightly. Dry Cells Are Rechargeable In a new rechargeable dry cell the con- tainer is a cylindrical zine plate which serves as the negative electrode, and the positive plate an especially designed grid said to prevent the active materials from falling out. The moisture needed by the battery from time to time is supplied by adding two or three eyedroppers full of distilled water every two or three months. The cells may be used singly, but gener- ally are put up in six-cell units in cabi- nets, with built-in rechargers; the whole outfit is then connected with the radio set and the 110-volt house-lighting supply.

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662 POPULAR MECHANICS “Canned” Radio Set Eliminates Body Capacity Radio sets having shielded units are known as “canned” sets. Several types are now on the market, and are attracting much favor- able co m- ment. The set shown is

“Canned” Radio Set, Showing the Various Units In- closed in Metal Containers one of the tuned r.f. type and is inclosed in nickeled brass; each tube is shielded in metal stalls, eliminating body capacity and adding much to the efficiency of the set. The fields of the various coils also are confined, limiting the troublesome stray pick-up which is so common with the unshielded types. Simple Connections for A-Battery Charger and B-Eliminator The problem immediately confronting the radio builder, or the purchaser of a new set, is proper

et of the pull-apart-type and the necessary lengths of lamp cord are required. li there is no wall socket near the set, an extension cord can be used. If the set is of the cabinet-type the pull-apart socket may be mounted at any convenient point near the set; if a console is used, the lamp cord is brought in through the rear of the battery compartment and the socket mounted on the inside. Mount the switc! at a convenient point, and run the wires as shown in the diagram. Two leads are taken from the one side of the wall socket so that the 110-volt a.c. supply is avail able for both the charger and B-elimi- nator; note that the other side of the sup ply line goes direct to the switch-lever post. The other two lever-posts are con nected to the positive and negative ter minals of the 6-volt A-battery ; mark these terminals on the switch so that the corre- sponding leads to the set and the charger will be of the right polarity. When placing the A-battery on charge. plug the charger into the wall socket, and throw the switch over, connecting the charger to the battery and at the same time automatically cutting in the a.c. sup ply. When taking the battery off charge. pull up the switch to the off point, and remove ‘the charger plug; the B-elimi nator plug is then pushed into the wal! socket instead. When ready to operate tlie set the switch is thrown to the set con nections, and the B-eliminator is auto matically placed in operation. There should be no filament switch on the pane! of the set as this three-pole switch turns on the A-battery supply to the tubes and puts the set in operation. If there is a switch on the panel, it should be lett turned on at all times, and the three-pole switch used instead. This is important, as the B-eliminator must be turned off when the set is not in use, and if there is more than one switch, there is the chance that the operator

Ac l0-v. | WALL SOCKET will forget to turn 110 VOLT — °h50-cYCLE one of them off A.C.LINE Pulling the three pole switch to the upright position turns off all elec trical connections.

connections for the aa A-battery charger * ; and the B-elimi- s | nator. A number ELIM- Pe of switches are not paeeas i desirable, the fewer : : operations neces- B-POsTs) + sary the better. O SET The diagram here- with works out s — nicely, and the ener method is so simple that anyone can use 7 + it. <A three - pole Lm. TO SET double - throw @For DX recep- ? ] tion more volume can be obtained it the full rated plate voltage from the B- battery is used on the amplifying

A- one _ be as

switch, a wall sock- Diagram of a One-Switch Control for the Recciver, Battery Charger and B-Eliminator tubes.

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a oe AMATEUR i : BSI ITT aa Reshingling Your Roof By E. R. HAAN shingles should always be used. come in bundles, each containing enough The cost ot

Xu a A “a seas ANS, UP TO LOOSEN IT Removing Old Leaky Shingles; Laying Building Paper, and Ther Reshingling the Roof, Is an Easy Task That Anyone Can Accomplish

663

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664 POPULAR MECHANICS move the old shingles with the aid of a shovel, as shown in Fig. 1. Don’t rip off the shingles from the entire roof, or you might have the sad experience of seeing an unexpected shower drench the roof and the plaster ceiling in the rooms below, which would mean considerable expense. Start ripping off the old shingles along the bottom and work upward. Ordinarily it is advisable to remove enough shingles to leave a strip, about 6 ft. wide and ex- ‘ tending the length ~~ + SAWED OFF of the root. Drive all the old rusty nails down and tack a strip of building paper to the roofing boards. Then lay a double thickness of the shingles along the lower edge of the roof, allowing them to project about 1% in. over the edge, as shown in Fig. 2. You’ will notice in the draw- ing that the joints are broken, as in a brick wall, so each shingle covers about half of two shingles underneath, to prevent leakage. A length of 34-in. board, exactly 4% in. wide, which is to be used as a spacer, is tacked over the first row of shingles, even with the lower edge, and a new single row of shingles laid over the first double row, observing the precaution of laying them halfway over the ones underneath.. Shingle nails are used, and a_ shin- gling hatchet will be found convenient and less tiresome to work with than a ham- mer. Two or three nails are driven into each shingle in line, about halfway be- tween the thick and thin ends. Each time a row is laid and nailed, the spacer is moved up, and the same operation is repeated. As soon as the shingles nearly cover the first strip of paper, remove some more old shingles, drive the old nails down, apply another strip of paper, and proceed as before. After three rows of shingles have been laid, a scaffold is made as follows: Take a suitable length of 2 by 4-in. wood and nail three wide shingles to it, as shown in Figs. 3 and 4. Notice exactly how these are nailed to the scaf- fold so that they project about 3% in. from the edge. A second shingle is nailed to the first, with the thick end 4 in. from the thick end of the first. Then the scaf- fold is nailed to the roof. Four or five Method of Attaching Rid Roll to. the Roo f shingle nails, all in a row, are driven through the thick end of the upper shingles on the scaffold and into the shingles on the roof. By leaving %-in. clearance between the edge of the scaffold and the edge of the row of shingles just above it, a couple of shingles can be set up to hold the whole bundle, as indicated. A scaf- fold of this kind will support considerable weight, and when it is to be loosened and moved, it is merely turned over as indi- cated by the arrow. When the ridge of the roof is reached, saw off the shingles at the edge and after the other side of the roof has been reshingled, ap- ply a ridge strip, which may be of wood or metal, as shown in Figs. 5 and 6, respectively. The latter can be obtained from any lumber-supply con- cern. Most old houses have the roof boards spaced 1 or 1% in. apart, as shown in Fig. 1, which was done mostly for the sake of economy, but newer houses have the roof boards laid close together. li desired, asphalt shingles can be laid instead of wooden ones. On new houses this can be done without making any changes, proceeding in the same way as with wooden shingles. However, a scaffold of the type described cannot very well be used when applying. asphalt shingles as leaks through the nail holes would result, whereas the shingle nails will not go through the wooden shingles entirely, if nailed near the thick end. On old houses having spaces between the roof boards, it is advisable to fill these with strips before applying asphalt shingles. Continuous hip shingles of metal can be used on buildings that have hip roofs. e Board or Metal Ridge after Shingling Fumigating the Incubator For best results, an incubator should not only be cleaned thoroughly before it is used, but it should also be fumigated. Get a formaldehyde candle from a drug store. Set it in the incubator. Light it and close the door almost tight. The fumes will kill all the germs that may be lodging there and this will better your chances of getting a good hatch. Air the incubator two days before setting eggs.

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(eel Ornamental Figureheads for the Canoe 1 are drawn in, saw riend trace out the he coloring. The viece of soft pine, if you want to be the first in ehborhood to have something ttractive and novel in the ake some figureheads for the canoe. igureheads, you may know, were al- avs attached to the prows of old ships s a sort of an emblem of good luck. hey were carved in beautiful, grained oods, and some that have been pre- your really boat line, erved in the marine museums are works art. So, just-as a good-luck charm, et’s see what can be done to decorate the ww of the canoe. The illustration suggests four different odels that can be used and, of course, our personal likes will suggest many ore that can be as easily made. If you ive no artistic ability, let an artist shape and suggest figure chosen for ur decorative scheme must be one that ill lend itself to being shaped to fit the irved end of the canoe. Thus the goose, e moose and the bear fit the purpose mirably. The selected one can be marked out pencil on the surface of a smooth cedar, cypress or any which is easily sawed and When the outline and details out the portions that uitable wood, hittled. POPULAR MECHANICS 665 can be reached with a keyhole saw. Then cut out all smaller details of the edges with a sharp jackknife until the final out- line is finished. After that, go over the edges and both sides with fine sandpaper. Draw in the details again with a soft pencil and give the board a coating of shellac. Prime the board with flat white paint, and when dry, the details can be painted in. As the outlines of the details will show faintly through the priming coat, no redrawing will be found neces sary. Use artists’ colors if possible and work from a colored print to get the col oring® correct. When completed on both sides, set it aside to dry for several days After the paint has hardened, the surface should be given an application of spar or automobile varnish. Do not use floor varnish, as this will become white when wet. Screw a thin strip of oak to the curved part of the back of the figure and let it project 2 or 3 in. at each end. Then, after removing the brass molding from part of the bow, screw the strip in its place. This will support the figurehead rood in front of and at the top of the bow a illustrated.—L. Massachusetts. B. Robbins, Harwich, Ornamental Figureheads of a Goose, a Moose, or Any Other Suitable Design, Are Distinctive and Novel, and They Can Readily Be Made by Anyone Having Some Artistic Ability

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666 POPULAR One-Man Barrel Lifter One man can easily stand or tip a bar- rel weighing from 400 to 500 lb. by using the simple lever shown in the drawing. It is merely a pick handle, with steel grips bolted on. Ap- plied as indi- cated, the handle’ allows pick / HANDLE. Handling Heavy Barrels Is Facilitated by Using This Simple Lifter considerable leverage and makes it com- paratively easy to manipulate heavy bar- rels.—Clinton Hinman, Naugatuck, Conn Running In New Motors New motors, with all bearings and parts fitted tight, are not immune from trouble, as is generally supposed, but must be handled and treated with care. The writ- er has endeavored to incorporate into a few brief rules, the precautions necessary to observe during the first 1,000 miles of use of the motor. Add 1 qt. of oil to every 10 gal. of gaso- line, continuing this for the first 500 miles of operation. Never exceed a speed of 25 miles per hour or drive in high gear at a speed less than 5 miles per hour. Never open the throttle wide, permitting the en- zine to race, when the car is standing still, or while shifting the gears. Avoid having the engine running with the spark retard- ed for any length of time or to idle in this condition. The overheating resulting from this practice, causes bearing wear, stuck valves and rapid carbonization. Rich mix- tures are invariably used with new mo- tors, which, combined with the fact that piston rings are seldom lapped into the MECHANICS cylinders, permits considerable seepage and dilution of crankcase oil. The diluted oil fails to lubricate properly with conse- quent bearing damage. The oil should be changed aiter the first 150 miles, again aiter the next 500 miles and also every 500 miles thereafter. The unlapped pis- tons and cylinder walls are responsible for much metallic dust which contami- nates the crankcase oil. By changing the oil at the stated intervals, the clogging of oil distribution pipes and the gritting of gears and bearings will be prevented. Due to the excessive heat in a new motor, at- tention should be given to the cooling sys- tem. The radiator should be refilled daily and should be drained periodically. Out- side of the engine there are many new and stiff controls which become dry and will wear quickly if worked in this condition. Keep a filled oilcan handy, giving a few drops occasionally to each control and moving part, which will permit it to work itself into a good bearing seat—G. A. Luers, Washington, D. C. Easily Made Fire-Alarm System The accompanying diagram shows a simple and useful fire alarm. Two copper or brass springs of the flat type, are mounted on a wooden or qther insulating base, and a small block of paraffin is placed between the springs. The springs are placed in different parts of the building and are all connected to a common bell. If a fire occurs, the paraffin quickly melts, the springs make contact, closing the cir- cuit, and the bell begins we to ring at once. 4 a] ra yy 1 nth lJ Novel Fire Switches Which Close Automatically on Being Subjected to High Temperature

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ul POPULAR MECHANICS Grub Hook for New Land In clearing land for orchard planting, ie grub hook shown in the illustration is been found very satisfactory. It is perated with a team or tractor and two en, one driving and the other handling e hook, and is used like a plow, being al- = 77, Grub Hook for Clearing Land of Tree Roots; After It Has Been Used, Plowing Is Unnecessary lowed to drag through the ground to catch the roots. A deit turn of the handles frees it from the roots just pulled, without the necessity of stopping. After this tool has been used, the ground will be so well dug up that plowing is unnec- essary. The dimensions given in the drawing have been found to be about right. The points should not be spaced farther apart than 10 in.—J. H. Deniston, Bavfield, Wis. Soft-Focus Attachment for Enlarging A soft-focus attachment for the enlarg- ing camera, which gives excellent results for pictorial and portrait work, when the harsh, needle-sharp definition is not want- ed, can easily be made from a tin lid of sufficient size to fit snugly over the lens, and a small sheet of brass cloth. The top of the lid is cut out and the brass cloth soldered to it. This makes a diffuser which can be attached or detached at will. Various sizes of mesh can be soldered to as many different lids, and the set will provide diffusers suitable for any work. Very good results can be obtained by ex- posing the paper only half the necessary time, and then completing the exposure with the diffuser attached. This gives a suthciently sharp image which at the same y" a li LY for co ~? ' GAS-PIPE. SPACERS time possesses softness. Good, rich blacks are obtained by giving short but sufficient exposure, whereupon the developing is done in restrained developer.—L. C. Fer- guson, Ontario, Calif. Removing Glass Bottle Stoppers Many devices have been suggested for removing stuck ground-in stoppers from bottles, but for ease in manipulation the wooden handle shown in the drawing is’ hard to beat. It con- sists of a strip of wood in which a slot has been cut to fit over the glass handle on the stopper. To loosen a stopper, = place the wooden handle over it and try to twist it backward and forward gently. After a few attempts, the stopper will be loosened. Only a gentle effort is required, and it done with care, the glass handle will not be broken —C. A. Oldroyd, Barrow-in- Furness, Eng. GLASS STOPPER » oe

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en 668 ture Novel Sled Built like Chair The novel chair sled shown in the photo is quite a departure from the conventional design and in many ways preferable to the latter. One sits on the seat while foot- rests on the runners permit another to stand up behind. The weight is well dis- tributed and a handle is provided so that the child standing can hold on securely and also steer the sled. The average boy can easily make one of these from scrap lumber usually found around the house. Strap iron can be used for runners.—W. H. Soames, Minneapolis, Minn. Effective Method of Trapping Rats A neighbor of a friend of mine has an effective method of catching rats which might well be tried by anyone who is troubled with these pests. He takes ad- vantage of the fact that rats will go to great pains to get water during a dry sea- son. Fora few nights tubs or deep buck- ets are placed in a barn or basement or in the alley. These are filled with oats or crumbs of bread and enough water is poured in them to come about halfway up the sides. The rats soon learn to dig into the bait for the water. Aiter they have been running to the water a few nights the bait is emptied from the tubs and replaced with water, the tubs being half filled. The surface of the water is Chair Sled Accommodat- ing Two Is Latest Depar- irom Conventional Sled Design POPULAR MECHANICS covered with screenings of corn or other grain. During the night the rats come as usual, but when leaping over the edge of the ves- sel they find themselves trapped in the water and soon are drowned. He caught as many as 14 rats in three tubs one night, of which seven were in one tub.—August Jeffers, Bedford, Ind. Packing Groceries The proprietor of a self-service grocery store has solved the problem of packing and display- ing staple articles, such as dried beans, fruits and similar bulk commodities, in the following way: A screw-top bottle is filled with the article contained in the shelf divisions, and on this bottle a label is pasted, giving the name and price of the goods. During spare time, the clerks weigh out and wrap packages, and the shelves are kept filled, so that the customer need not weigh his own bulk goods or have someone else do it. By making the packages of uniform size, the difficulty of dealing with fractional units is eliminated. Reinforcing Stove Lining After relining my kitchen stove several times, I found that the lining first gave way under and between the pipes, git where the layer e >) of cement was ee é ro HOT-WATER thin. To length- ie COILS, en the life of the a lining, a piece of 4-in. mesh screen was bent around the pipes but not against them, as shown in the drawing. Through this screen the cement was worked with a _— trowel. A few \ slender wooden _ tINING’ sticks were also imbedded in the lining, which tended to reduce, if not entirely eliminate, warping and shelling. Of course, no portion of these sticks was left uncovered by cement as they would then burn. - This method of reinforcement was, found entifely satis- factory.—R. C. Tarr, Gloucester, Mass. STICKS? ‘ WIRE SCREENING

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rrr

Two Simple and Interesting Toys By W. P. MOTT and L. R. BUTCHER ““ T= extension “duck pond” toy shown in the first illustration is an easily ide article, which, when not in use, ds compactly. The supports for the icks, lilies and figure are strips of soft ood, % in. thick, 3% in. wide and 6 in. ng; eight of these are required, and vo more of the same stock, 8 in. long, yr the handles. The strips are stained a ray-green color. The ducks are made of ny available thin wood or veneer, sawed to shape with a coping saw or fretsaw, nd painted white with yellow bills. <A ttle stud should be left extending from he base of each duck, about % in. long; his is inserted nto a hole lrilled in the trip when as- el ibling. The EM TE MMAR LOGINS i 0 IE A TITLING: AE A EM SS I ON ye me a ome

bottom. If small washers can be obtained and used under the heads and ends of the brads the action of the toy will be more smooth, but the brads alone will serve very well if washers are unobtainable. The interesting toy group shown in the second illustration is made to resemble four chickens, which go through the mo tions of feeding. The swinging of a pen- dulum suspended below the group causes the “head” of each of the figures to rise and descend alternately. <A slight touch of the weight causes the movement to Start. The base is made of ordinary wall- board. The I4- in. holes are made to re- ceive the dowels’ which A Simple “Duck Pond” Toy That Any Boy Can Make; Variations of the Design Will Produce Other Inter- esting Toys lies are made of the same material as the ducks and colored with green stems and leaves and purple blossoms; the fig- ure also is of the same material, and has a blue gown, brown hair and basket. The method of fastening the figure and the lilies to the strips is the same as followed for the ducks. Take four of the 6-in. strips and one of the 8-in., lay them edge to edge, close together, and aline them at one end. Draw a pencil line across all the strips, measuring ‘46 in. from the end of the 6- in. strips. Draw a similar pencil line across the other end. Do the same with the remaining four 6-in. strips and the other 8-in. one. Draw center lines down each of the strips, then assemble them, as shown in the plan photo, and nail. The nails used are small brads, and they are driven through the strips, % in. in front of the center line of the strips, so that the toy, when extended, will assume a cir- cular form, instead of shooting out straight. The brads are clinched on the support the figures; the larger holes ac commodate the strings from which the weight is suspended. The circular shape is but a suggestion; the holes, however, should be located as shown, from the center, if the sizes given for the other parts of the toy are followed. The body of each chicken is made by turning a piece of wood to the erg shaped form shown. Four of these are required; if a wood lathe is not available, ordinary round dowel stock of approximately the correct size mav be used Even thread spools will serve. The hole at one end is drilled “46-in. to hold the tail. The 4% in. hole is for the supporting dowel. The slot at the end allows the head to swing freely on a pivot pin, the location of which is shown in the drawing. Ordinary dowel stock is used for the supporting pins shown. These are glued to the bodies and the toy assembled by pointing the heads of the chickens toward the center of the base. Glue is also used to fasten the pins firmly in the base. 609

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670 POPULAR MECHANICS The head and tail need slight explana- tion Stout cardboard or light sheet metal is used for stock in making four each of these. The head pieces are pierced as shown. The low- er hole is. for Vids the string which WALL: _-” BOARD DETAIL OF \ ra BASE “The Feeding Chickens,’ Another Simple Toy, the Design of Which Can Also Be Modified to Suit the Maker is attached to the weight: the hole slight- ly higher up is for the pivot pin, while the top hole is the eve of the chicken. A piece of string, 9 in. long, is fastened to each of the head pieces and passed through the %-in. hole in the base. Each of the How to Make a Fluorescent Screen Many experimenters have occasion to use a fluorescent screen, particularly those interested in X-ray work. Such a device is quite expensive if purchased, and may be made as follows: Mix 1 oz. each of common salt, sodium tungstate, and calcium chloride. Place the mixture in a crucible and heat it dull red in a coal fire, for several hours. It will melt into a clear liquid, and should then be removed and permitted to cool. The liquid will crystallize into a hard glasslike mass. Break this out of the crucible and crush it into small pieces.

head pieces is then pivoted to a body by means of a small brad driven through the body and passing through the pivot hole in the piece. The tail pieces are pressed into the holes pro vided for them. is Paint the bodies Z brown, the heads oi = goer —— 6 +b = 4 .. BODY-SUPPORT PIN, 4 REQ,

ENLARGED DETAIL OF HEAD, 4 REQ. - PIVOT PIN <«— SLOT FOR HEAD

7. a ae 13+ SIDE hy DETAIL OF BODY, 4 REQUIRED white with red combs, and the tails black. The, ends of the four strings are attached to a weight below the base. Care should be taken to have the strings as nearly even in length as possible. As the pendulum swings, the heads of the chickens move up and down in a lifelike manner as long as the weight is in motion. Put them into a jar of clear water. The sodium chloride resulting from the chem- ical change by heating, will gradually dis- solve and the calcium tungstate will fall to the bottom in fine crystals. Wash this precipitate until all trace of the salt dis- appears; then pour the crystals upon a sheet of filter or blotting paper to dry. After drying, place them in a mortar and grind them to a fine powder, when they will be ready for use. To make the-screen proper, procure a piece of thin white cardboard of the size desired. The cal- endered board known as three-ply is sat- isfactory. Paint the cardboard on one side with a thick solution of gum arabic

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all 609 POPULAR MECHANICS 671 in water, or better still, with celluloid dissolved in amyl acetate. Permit the cum to become “tacky” before dusting vith the chemical. ‘The latter process re- quires care, to produce an even layer on the cardboard, and it is advisable to prac- tice with ordinary salt before attempting on the cardboard for the screen. The calcium tungstate should be placed in a dry jar and a piece of fine muslin fixed over the mouth of it. The chemical may be dusted over the surface with this sieve. Shake off the superfluous crystal and permit the screen to dry thoroughly. Fasten a piece of mica, or sheet celluloid, over the sensitized surface to prevent lamage to it. Mount the sensitized card- board in a wooden frame of suitable size ind arrange a hood around its edges to ut out unnecessary light. The sensitive ide of the screen is, of course, held to ird the observer. Wooden Roller Made without Lathe lf a lathe is not available, a small hard- vood roller to mount on a short journal can be made as follows: The piece of vood is drilled through lengthwise for a driving fit and the journal driven in. Then the block is roughly | =i shaped up to | approximate size by split- ting off cor- ners. Spools are _ slipped over the ends of the jour- nal, and the whole is mounted in an impro- vised fixture made of 2 by 4-in. hard- woo d. ‘ he holes for the journal are drilled for a tight fit and centered below the top of the block and board just the radius of the finished roller. Then a car- penters’ jointer is used to plane down the roughly formed roller, care being taken to start the stroke at the end of the roll- er and stop it before the bit of the plane hits the end block. The roller is turned, until it is planed all around, then finished with a fine file. Improved Electrode for Water Rheostat Water rheostats are usually made of a large glass or porcelain jar containing horizon- tal electrodes. ROD ~~___ IRON An improved pa ~ SPIRAL vertical elec- id trode which has a greater surface than that of the horizon- tal type, is shown in the drawing. This form al- lows the gases to es- cape more easily. The electrode is made ofa strip of gal- vanized iron, 1 in. wide, bent to form a spiral with a COMPLETED RHEOSTAT in. space between turns. Two strips ot iron are crossed on the spiral and soldered to it where they touch. The vertical rod fastened to the crosspieces, which may be done by drilling the latter and thread ing the rod. Two of these electrodes may be provided or one of them may be simply a rod. Of course, greater current will be passed if both electrodes are of the spiral type.—H. Busholwitz, Philadelphia, Pa Economy in Motorcycle Tires Caution in the use of motorcycle tires with a minimum of abuse will result in a considerable tire saving. Tremendous wear on a single spot results when the power is thrown in so suddenly that. the driving wheel makes several revolutions before gripping the ground. he prop er air pressure must be maintained in the tires in order to obtain good wear. Guess ing is a poor method of determining the air pressure, and the exact condition should be noted from time to time with a gauge. Ordinarily, a pressure of 45 to 50 lb. should be maintained in the rear tire and about 20 per cent less in the front tire, in the case of 3-in. tires. Rim-cut ting from running motorcycle tires un derinflated is the commonest abuse. Dents in the edge of the rims cause undue wear on the tire, the fabric being worn through by the constant rubbing. Bent rims are often caused by insufficient air pressure in tires, the liability to injury being in creased when crossing tracks or bumps.

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672 POPULAR Old Shutter for Chicken Run Because the most of the new-hatched older chickens consumed feed, leaving little for the ones, one tarmer made a Old Window Shutters Make a Good Chicken Coop That Will Keep the Larger Fowls Out coop from four old shutters, as shown in the illustration. With the shutters wide open, only the small chicks can scramble through to the feed thrown in through the top, while the large chickens feed outside. When the shutters are closed, the chicks are protected from. driving wind, and an old blanket is sometimes thrown over the top to make the comfortable. Later, as the chicks grow, some of the shutter panels are removed to permit their passage—Dale R. Van Horn, Walton, Nebr. coop Automatic Control for Homemade Refrigerator I have constructed a couple of home- made refrigerators like the one described in the November, 1923, issue of Popular Mechanics. I made it unnecessary to go to the machine to start and stop the mo- tor, by installing an automatic pressure- control switch. . These switches may be bought at a cost of $8 to $15 and the in- stallation is quite simple. Place a tee in the pipe leading to the high-pressure gauge and run a line to the opening tapped in the base of the switch. The MECHANICS wiring to the motor is changed and run to the line terminals in the pressure switch and the wires from the load ter- minals are connected to the motor. In operation, the switch is adjusted to kick the motor on and off, to keep the pres- sure within the desired limits, by turn- ing the large screw on top of the switch until the desired adjustment is obtained. After the switch has been installed and properly adjusted, the outfit will require no attention other than an occasiona! in- spection—Leon D. Quick, Milesburg, Pennsylvania. Cooking Food on Auto Heater Nearly all modern automobiles are equipped with some sort of heater, espe- cially if the car is of the closed type. | have a small sedan in which I installed a tloor-type exhaust heater, as shown in the photo. The heater itself consists of a cast-iron body through which the hot gases circulate, and a perforated cover, which keeps passengers’ feet or other ob- jects from coming in contact with the hot surface of the heater. On most heaters this perforated cover is bolted solidly to the heater top. I removed the cover and riveted hinges on the edge next to the back seat, then fastened it to the heater top so that it could easily be swung up, leaving the heater top exposed. If the motor is run a few minutes, the heater top will become very hot so that, if the Auto-Floor Heater That Can Be Used Effectively for Cooking Meals ‘ cover is swung back and cooking uten- sils are put on the heater as shown, eggs, coffee and many other things can be cooked as well as on any common stove. I can boil a quart of water in four min- utes with the motor running slowly. Of course, it costs a little more to cook this way than on a gasoline stove, but the big advantage is that it is always available and takes up no extra space. If the road is smooth, one can put a coffee pot on =

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= % POPULAR MECHANICS drive along until it is boiled. The can be prevented from being shaken the heater by using a piece of wire to dy it. Altogether I have found this ter a very handy device on the road.— Ie. Granville, Cincinnati, Ohio. Applying Wall Paint ine of the most common reasons why ny amateur jobs in painting fail is im- er application, particularly in wall When painting walls, the amateur ly works horizontally across the wall 1 the ceiling down. It is impossible » a good job in this way, as the laps never be covered, nor can sufficient ce be painted in time to lay on an ional strip before the paint of the ‘eding lap has dried. The secret of cess is to paint a strip about 2 ft. wide 1 the ceiling to the floor and cover this The next,lap can be painted re the paint of the first lap has dried the edges of the laps will never be eable. This is quite a valuable hint this method of painting does not re- lire any particular skill and can be used vith all colors. ot vell. \ Lighting the Gasoline Lamp Many people have new gasoline lamps of the kind shown in the drawing. It is rather difficult to light them with matches ind unhandy to do so with a torch made of paper. A better method is as follows: Bottles of shoe blacking in liquid form have a little brush at- ) —~f tached to a P Ny cork. The / sponge or bhat- / \ ting on the | end is pushed up, which Caves a hook yn the end so that it can be hoo k e d on he mantle. Che batting is horough- saturated in kerosene, lighted and can easily be blown out atter the gas- oline vapor been ignited.—Charles Plattsburg, N. Y. Latour, as Jr., Floating Bait Box Fishermen will find the floating box shown in the drawing of considerable con- venience as it is always within easy reach and, as it is submerged, keeps the min- COVER . = ght as - ~~ Floating Box Keeps the Bait Alive nows alive. It is made from a piece of 4-in. wire mesh about 18 in. long and 6 in. wide, the ends being soldered together to form a 6-in. cylinder. Two 6-in. tin can are on the ends but before doing this the top cover is screwed to a wooden disk, cut from 1l-in. material, covers soldered and a 4-in. circular hole is cut through it and the tin cover, to permit getting the bait in and out. The box is tied to the boat by a cord attached to a staple in the cover Greasing Ford Ignition Systems Special battery-ignition systems used on Ford cars have a casing at end in place of the timer, which contains a the lower pair of gears running in grease. It is a good plan to drill and tap a hole in this casing, at a point which will not intertere with the gears, and to install a grease cup or high-pressure fitting. Grease can then easily be forced into the casing when nec essary. There is not much space back of the fan, so that care should be taken to place the grease cup where it cannot be struck by the fan.—E. T. Gunderson, Jr., Humboldt, Lowa.

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674 POPULAR MECHANICS How to Make a “Swimming Johnny” A “swimming Johnny” is an amusing toy, and one that any boy can build from odds and ends about the house. Properly ARMS ia // BEARING a fj VES ELastic €& IV BAND ~ oa the assembled, it will travel several yards in calm water and can be used in the bath tub as w ell as outside. The body, cut from a piece of sott pine or cedar, is 8 in. long and 2in. wide. Bevel the corners of what is to be the front end and taper the sides toward the rear as indicated. Cut out a head and taper the bottom down to a slender neck which can be fitted tightl into a hole an inch from the front of the body. Cut a square hole just back of the head to take a small spool as shown. On each side of the body screw a piece oi brass or tin to serve as a bearing. lug the spool, force a piece of stiff wire through the wood and fit the ends in the bearings, allowing them to project about 34 in. The arms consist of two pieces of soft wood beveled on one end and the opposite ends are fitted securely over the ends of the wire axle. Be sure the bevel is uppermost when the arms are forward. Connect the spool with a long elastic band that passes below the body and attaches to a screweye near the rear end. This should be just taut when the spool is un- wound. Paint the device any suitable color and oil the spool and the wire in its bear- ings. The head can be painted any de- a Amusing Toy for Children Which Re- ma sembles a Person Swimming sign desired. Wind up the elastic on spool until it is quite tight, being sure wind the arms to the right when the hi faces left. Place “Johnny” in the w and let go of the arms. They will thr around in an overhand stro and push the toy ahead at a go speed.—L. B. Robbins, Harwii Massachusetts. Protecting Water Meters Hot water is now being ol tained during the winter mont from many hot-air furnaces by ~ serting a pipe coil into the fi | box, which in turn is attached t H the boiler. It happens in t! majority of well-designed jol that the water is overheated du ing very cold weather, which p: duces steam and causes conside1 able pressure on the water-suj ply line, forcing the water to bac! up through the meter. This ruin the meter for future operatio: The practice of obtaining hot water from the furnace cannot then be continued unless som: method of protection for the meter is provided. In the accom panying illustration is detailed a: arrangement of two inexpensiv: fittings, which can easily be i: stalled. On the house side of the mete: install a horizontal check valve and imme diately behind it a small safety valve, set to the proper pressure. Setting this val is not dificult. It should be set about lb. above the maximum pressure whi: has been known on the water main. What happens when the water in the boiler get up excessive pressure is this: When tl pressure on SWINGING the boiler CHECK VALVE } overcomes ¢ the pressure on the water line, the 1 ’ check valve = aonstiod a. WATER clo mtu rey METER \ safety valve ' SAFETY VALVE ~ opens taking \ care of the WATER INLET boiler and at the same time saving th cost of a new meter.—L. H. Georger, Bui falo, N. ¥ @A double-filament headlight lamp ca: be used again for a tail light after the bright filament has burned out, by drop ping solder between the two contacts which makes it a single-contact lamp.

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Vy $ BUILT-IN FURNITURE 2% FOR THE AR i OME Y/ [tite ih ui WD A Ban? Part XVII—Building In Bathtubs § bee four-legged bathtub is rapidly be- oming obsolete. Housewives rightly lemn it as unsanitary and productive innecessary The high-priced iving porcelain aprons extending to floor are ideal, but the expense of re- ing the plain tub is prohibitive to \ However, any handy man can ise in a tub for plastering or compo- tion surfacing; and tubs of almost any ipe, whether installed in a new house long in service in an old home, can be ‘losed, to the great increase of beauty cleanliness. For a round-end tub, plumb down from the edge to the floor and draw a line 1% in. behind that point on the floor. Against the end wall, nail a 2 by 3-in. stud, suitably tapered to fit under the rim. Where the curve begins, put up inother stud and, labor. between the two, nail a wedge-shaped ,4+77}+77) 2 by 3-in. plate. Put +7[i+-7 a third stud under ~7 | the plate, midway between the others. | Keep them plumb. id Sheath with 1 by 6- in. stock, run hort- zontally, the upper board wedging tight- ly behind the tub im. To obtain nail- ing for the end heathing, it is nec- = essary to cut seg- /4 ments of circles irom l-in. stock to a radius 1% in. shorter than that of the tub ~o-" end. Nail one set to the floor after hav- 1 ing plumbed down ++. 4-4 4 4+ 2'XS"PLATE 0g BEHIND RIM EDGE.) |): from the rim and measured 1% in. back for points on the curve. Another curve, fitted roughly to the tub at a distance 4 in. below the top, is supported by two short studs cut underneath, while the ends are nailed into the side stud. These curves may be continued around the end of the tub toward the wall, or may be built out straight from the center, the end housing meeting the wall right angles. Sheath with narrow vertical strips braced against the rim. If it is desired to plaster the tub, set the studding back from the rim only 34 in. In this case it is advisable to use waterproof cement for. plastering, al- though the hardwall plaster, well enam- eled or covered with oilcloth, is fairly satisfactory, particularly if a thin band of wood is run around the rim, covering the a joint with the plas- (2X3 STUDS ter. Such a band should be coated on the back with thick white lead nailing in place, to prevent water from working behind it. A tub, with or without a side apron, Hes before SIDE SHEATHING SHOWN +N DOTTED LINES built into a recess in OD VERTICALLY WITH the bathroom is il- NARROW STRIPS lustrated in the drawings. At the free end, a wall is built to the ceiling and returned on the face of the tub to make a post 8 in. wide when plastered, while a_ pilaster of the same width is built against the end wall. Between these is plastered an ellip- 675

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676 FC.+CFSAB; AD-BD=FE-EF*FE+EF'+2 LAYOUT OF ELLIPSE “> . TUB EDGE BLOCKED 2%"BEHIND FRONT ”\ TRIMMER % ' TRAPOOOR } OPENING tical arch, beginning at the height of the door (usually 6.ft. 8% in.). Build the arch or the end partition first, according to the direction in which the ceiling joists run. For the end partition, cut a plate, 2 ft. 7% in. long, and cut three 2 by 4-in. studs long enough to force the plate tightly against the ceiling. Nail one at each end ot the plate by spiking through the latter. The third is nailed in- the corner stud with thick enough blocks separating them, to form a post in. wide. Nail a trapdoor header 1 ft. in. from the lower ends, if the fixtures are on that end of the tub, and cut a fourth between it and the plate. Raise to posi- tion and plumb carefully before nailing the plate to the ceiling. If there is not enough room in the bathroom to allow the end wall to be raised in this manner, nail up the wall stud and plate and put up the studs one by one, toenailing them with eight-penny commons. Plumb up the end wall 2% in. in front of the edge of the tub, and nail up a wall stud and the plate. Make a double header of-2 by 4-in. stock, well spiked together, to nail between these wall and corner studs. Level it and nail three sltort studs above. Trim the sides by nailing one stud against the corner post and blocking an- side ct 20°"— OPENING POPULAR MECHANICS other from the wall stud, so that, plastered, the posts of the arch will equal width, as shown in the drawin, is necessary to fit these studs aroun front of the tub. If the tub has no a; but is to be plastered or tiled in front, up under the rim, as shown in the d ing, for the round-end tub. For tile rough work should be 1% in. from the edge. Tar paper and heavy wire or m lath over this are used to key the cen backing to the tub. Fit a splash apron of 1 by 6-in. b board around the top of the tub, sett the lower edge in heavy white lead: remove the lath and plaster to the sired height and cut between the stud by 6-in. stock, 1% in. back from the i To di the elliptical curve, lay out on a floor: straight line equal to the width of rough arch, and at the center erect a p: pendicular equal to the desired height of the plaster, for a tile apron. the curve, Tie loops in the ends ot tring of fine wire, which, when stretche will have a length equal to AB in the di gram, the width of the rough arch. Wit one-halt of AB B as a radius, and E, tne t of the perpendicular, as a center, stri! ares through AB with a pencil point the loops, giving the foci F and F?. Dri brads in these points, ioop the string ov: them, and trace along the string with pencil on a piece of cardboard laid unde: neath. Only one-half need be traced, a the pattern can then be cut out and re versed for the other half. Make fou: ' brackets, allowing % in. of stock above —_

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=F’ POPULAR cutting the ends tafgent with the ve. Nail these under the header, keep them back a lath thickness from the es of the studs; then tack on pieces of to fur out the side lath for key space the plaster, and lath square across the kness of the arch. Stretch a strip of tal lath of wire mesh, 18 in. wide, und the thickness of the arch and nail e together to take out all puckers or nkles. Put metal corner beads on the ight sides, plumbing and gauging for thickness of the partition. im the trapdoor opening to 1 ft. 8 in. idth, and make a jamb, 1 ft. 4 in. high 1 ft. 6 in. in width, using 1 by 4-in. k Rabbet the head jamb into the MECHANICS 677 head level, front edges projecting 3% in. outside the studding, forming grounds for the plaster. Aiter plastering, miter around a flush casing of 1 by 2-in. stock, and 1% in. behind the face, nail stops of 3g-in. material. Make a panel door of 1% by 3-in. stock and fit into the opening. Secure with two small brads driven through the stiles into the jambs. This is to enable a plumber to work on the pipes in case of stoppage or other trouble. Cut blocks between the studs to stiffen them, and the frame is ready for lath and plaster. Since the beauty of the arch de pends on the smoothness of the curve, see that the plasterer does not turn the curve into the are of a circle by pointing the Set with the sides plumb and the ends and flattening the adjacent curves = MATERIAL LIST | Recess Tub Round-End Tub eces, 2 by n. by t., pine or fir, SISIE 1 piece, 2 by 3 in. by 14 ft., pine or fir, SII | eces, 2 by 4 in. by 16 ft., pine or fir, SISIE } pieces, 1 by 3 in. by 10 ft., pine or fir, S11 ece, 2 by 4 in. by t., pine or fir, SISIE 1 piece, 1 by 6 in. by 14 ft., pine or fir, SII piece, 1 by 8 in. by it., pine or fir, SISII 1 piece, 1 by 4 in. by 14 ft., pine or fir, SIE iece, 1% 1 n. by 6 ft., pine or fir, S4S, sanded Cost iterials, about $1.50. Time to build, ab | ( t t ils, al } Time, about 8 |} s ] ° Making Round Rods for Fish Poles In looking forward to the enjoyment that may be had in the spring, it is well prepare and overhaul the fishing ap paratus or the shooting equipment. In loing so, it may be necessary to make i joint for the fish rod or perhaps a rod or the gun. These can be easily cut if they are sized and run through holes e in a piece of thin metal as follows: \lake several holes of the desired sizes in i steel plate, and ream them out with a rather dull taper reamer, so as to leave a bur on one side. This bur should be filed lown almost level with the surface of the etal, leaving the edges flat and sharp. a rod of wood from which the article to be made is put in x hole and drawn hrough from the op- posite side to the bur, i nice round rod will result. As the rod be- comes smaller, use a maller hole un- til the required diameter is ob- tained. A saw blade that is not too thin is about the proper thing Price to use for the \ 1 nad steel plate. It will be necessary to draw the temper to make the holes, but it is not necessary to retemper it after the holes are made. Saving Stain in Treating Shingles Staining shingles is usually accom- panied by-a considerable waste of stain because the shingles are laid aside after dipping and the excess stain drips onto the ground. A method of doing this work with minimum waste is shown in the _— photo. The dipped one shingles are laid in a trough so that the exces stain will run back into the container. A good trough for this purpose can be made by nailing together two pieces oO! wide board, about 6 ft long, and arranging a pair of legs at one e nd. | h © other end is placed over the edge of the stain barrel or can. By this means practically no Trough for Holding Freshly loss or stain will Stained Shingles Prevents Waste be suffered. “4

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678 POPULAR MECHANICS A Good Garden Weeder After breaking a tine out of his potato or spading fork a neighbor of mine made a handy weeder out of it by removing the other middle tine and riveting a piece of old saw blade across the points, as shown. With the two remaining tines bent to a slight curve, and the blade sharpened, the imple- ment is used much as one would use a shovel, slic- ing down the weeds wit h- out any earth collecting on the blade. Small holes are drilled through the ends of the outside tines and the saw SAW BLADE blade beveled SHARPENED as_ indicated. Its shape can be altered to suit the user. The rivets are set midway between the edges of the saw blade and hammered down tight. The blade can be sharpened on an emery wheel and later finished with a fine file or oil- stone. The maker says much more ground can be covered with this tool than with a hoe, and that it makes the operation far less tiresome.—Dale R. Van Horn, Wal- ton, Nebr. Testing and Caring for Files To test a file hold it so that the light will be reflected sharply from the teeth and observe whether their edges are flattened and appear as white lines. If so, the file is dull and should be recut if of considerable size and value. Files should not be thrown into drawers and mixed with other tools, but should be set in racks or drawers made for the purpose. A mechanic would not throw a straightedge into a drawer con- taining other tools, and a file should be given similar consideration, as every nick in the teeth impairs the efficiency of the tool Files may be sharpened by dipping thei into sulphuric acid, but care must be taken not to permit the acid to come into contact With one’s clothes or p son. Water is used to wash off the a Each should be provided with an i: vidual handle. This prevents injury the hand of the worker and aids in 1 proper use of the file. Handles sho be carefully fitted and be made of a s proportionate to the file. In removing, handle from a file, strike the handle the end nearest the file, by sliding a pic of hard wood along the surface of t!] file, as the blow is struck with it. Do. use another file or metal object in tl removing a handle, as it will injure t! latter. Stove Forms Homemade Furnace The renter of a small home had no fur nace, so he planned a method of pr viding heat for the house at a minimu: cost. There was a small pit under tl dwelling. He obtained a stove at secondhand store, and a lot of bric! that had been discarded from a wreck: building. He purchased a large hot-ai: register, some lengths of stovepip: sheet iron, asbestos paper and cement With these materials, costing less th $10 all told, he built a satiSfactory fur nace, which worked well all through t! winter. The register was first placed i1 - \_COLD-AIR PIPE \--— ASBESTOS S USHEET IRON : \----STOVE Improvised Hot-Air Furnace Made from Ole Stove and Discarded Bricks the floor, between the living and dining rooms. The stove was placed in the base ment and walled up with brick on al! sides leaving only the doors in front ex posed, as shown in the illustration. A pipe connected the stove to the chim ney and another line of pipe ran from

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POPULAR MECHANICS bottom of the hot-air chamber to the » of the ground, thus insuring plenty ir. A damper, set in this pipe, regu- ed the amount of draft. When this | been done, the brick walls were con- ted to the register with sheet iron ered with asbestos paper. This is a «1 way for those without proper heat facilities or without sufficient cash obtain a good furnace. Backstop in Garage Prevents Damage Some garages for automobiles are only ittle longer than the car and there is n danger of running up against the | so that both car and garage may be maged. One driver built an up-sloping itiorm at the rear end of his garage that the front wheels would strike stopping the car effectively without danger of damaging it. This in- llation is especially recommended for experienced drivers. — Charles Latour, Plattsburg, N. Y. Bedroom Sandals Made from Paper Bags bedroom sandals are not always at nd, but a dozen pairs of paper sandals, hich will erve just as ell as the re expen- ive. article, in be made for just a few cents, Ordi- nary bags, ob- tainable at a grocery store, re used, the ze depend- ng on the ize of the oot for hich they re intended. he bag is £ xy BAG CUT ut away at he top on ne side, as hown in the ywer detail the illus- tration, to fit over the in- step. If the paper is stiff and the edges seem sharp, they can be folded over. These sandals keep the feet clean and may be thrown away after use.—L, B. Robbins, Harwich, Massachusetts. AWAY HERE 679 Makeshift Lathe for Emergency In the absence of a small wood lathe, a satisfactory substitute for some work can be made from a grinder as shown in the drawing. The emery wheel is first re moved and a wooden wheel substituted, Improvised Lathe Found Useful in the Small Workshop which serves as a taceplate on which the work is fastened with screws. A wooden brace, clamped to the bench top with a C-clamp, serves as a tailstock. An ort dinary plane can be used as a cutting tool, while the grinder is operated by hand.—B. C. Shilling, Walton, Ind. Cheesecloth Takes Place of Glass for Storm Doors and Hotbeds For poultry houses, hotbeds, a good substitute for glass ca be made by taking lightweight muslin and ironing parathin into it. An electric iron does a fine job, but care must be taken not to let the get too hot or the cloth will be scorched After it is treated in this way, it nearly transparent his treatment makes the cloth waterproot. storm doors and cheeseclot! or any ron becomes 1 also @ When new lumber, particularly white pine, contains many knots, it is policy to use less oil in the paint, sub stituting turpentine for the oil eliminated; oil in paint causes later coats to draw the sap out of the knots, and this natu rally leads to bad checking, but the sub stitution of turpentine for some of the oil prevents this. ood

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oo | YOURE UNDER | . |NOURISHED, BAT, 4 ee ae

Fig. 1, Sulphated Battery Plates, Note the Low Acid Level; Fig. 2, Plates Ruined by Sulphation; Fig. 3, Separators between Plates Worn COME ON hy, HE NEEDS WATER )

(iF YOU WERNT USED SO MUCH {MAYBE tCOULD! _ <<, - . COME ON BAT! GIVE US SOME JUICE y n “} ‘ rd } wo fy

How to Save Your Battery

The Little Black Box under the Seat Is the Heart of the Car: It Takes Only a Little Care to Keep It Healthy Dees battery! All motorists know what that means. It usually hap- pens just when the driver is farthest from a service station or just when he is in a hurry and can least spare the time to lug it to the station to rent one. Yet most motorists are themselves to blame for the run-down condition of the “box of juice.” because they will not spare the little time required for its proper upkeep. Even in summer, when the water in the battery evaporates tastest, it is not necessary to look at the battery more than once a week to see that the water level is main- tained. This takes only five minutes, yet we find owners who think it “too much trouble” to do this, and allow the water level to get down so far that the battery is seriously damaged before they will look at it. There is no need to study the storage battery deeply in order to take proper care of it. Simply knowing how to use a hydrometer ts enough—if the hydrom- eter is used. A storage-battery hydrom- eter syringe can be bought from any auto- supply house cheaply, and a bottle of dis- tilled water for 15 cents at any drug 680 store. With these the owner is equippe to add months, and sometimes years, t: the life of the battery. The hydromete: svringe has a small float inside of it; this is the hydrometer proper, and is marked or graduated to indicate the specific gravity of the acid solution in the battery As the specific gravity depends direct! on the state of charge of the battery the hydrometer tells the owner all he needs to know about its condition. To take a “gravity reading,’ remove the cay from one cell of the battery, squeeze the svringe bulb and insert the end of the rubber tube of the syringe into the liquid in the cell (this-liquid is called the elec trolyte). Now release the bulb and the electrolyte will be drawn up into the glas tube. Draw up enough to float the hy- drometer. The latter will float in the elec- trolyte at a height dependent on the spe- cific gravity, and the mark on the scale of the hvdrometer even with the surface of the liquid is the “battery reading.” After reading the scale, press the bulb and discharge the electrolyte back into the cell from which it was taken. Don’t neg lect this; never put electrolyte taken from =——

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=

Ee __ _—— SS POPULAR one cell into another. Read all the cells. Don’t depend on the reading from one or two cells only. If the reading is down around 1.160, have the battery charged immediately, and never permit the bat- tery to become discharged below this point. The following readings indicate the state of charge of the cells: 1.275 to 1.280, fully charged; 1.260, three-quarters charged; 1.225, half charged; 1.160, quar- ter charged. A cell is completely dis- charged when the reading is 1.125. If the readings of the three cells are the same within 20 points, that is .020 degrees on the hydrometer, then all three cells are running together in good order. lf one cell indicates more than 50 points below the other two, this is an indication of a partial short circuit in that particu- lar cell, and the battery should be placed in the hands of a good repairman at once. It is a good plan to make it a rule to test the gravity of the battery once a week, summer and winter. The level of the electrolyte in the cells should be in- LEVEL \

MECHANICS 681 more to take readings from the cells. lf the habit is formed of inspecting the bat- tery on a certain day, it becomes auto- matic and no trouble at all; therefore, keep up the weekly inspections through- out the winter so as not to break the regular routine, and spoil a good habjt. The level of the electrolyte should be maintained ™% in. above the plates, as shown in one of the illustrations, and pure distilled water only should be added Never, under any circumstances, add acid; this is a job for the repairman, should it ever be necessary. All this seems a lot of care when it is set down in black and white. As stated before, however, it takes but a few min utes a week; and if it is neglected—look at the illustrations! Fig. 1 shows the effect of neglecting the level of the elec trolyte. Sulphate of lead forms on the plates when left for a time in a discharged condition, and it will form much’ more rapidly on the plates that are not pro tected by the electrolyte. The low acid level in this particular cell can FILLER PLUG ACID i ae be seen very clearly marked on (2 the plates. This meant a job for

the repairman, and expense for

the owner. Now look at Fig. 2.

i f [* 1.275 SP.GRAV.~ JP

1300 INDICATING FULLY CHARGED CELL ! FLOAT— | Fig. 4, Buckled . — ) } 2d Broken Plates, ' Sen so Gemahieee AVERAGE HYDROMETER ing and Vibration READING | GEE, from Loose Bat- \ tery Clamps; Fig. 5, Plates Ruined by Overheating spected once a week in the summer anyway, and, as most people use the hy- drometer syringe to put water into the cells, it only

takes a couple of minutes atl

SECTION THROUGH CELL, SHOWING ACID LEVEL

1M ALL IN, GEN. These plates are very badly sul phated, and this was caused by letting them stand after the elec trolyte was spilled. The battery { SAY' WHEN YOUR PLATES ARE BUCKLED LIKE MINE MAYBE YOU WONT FEEL SO GOOD!

) es \ «Ks ‘ ) va Le We . LA 1G > b pf 4 o rg q < ¥) a ria - a

WHY DONT YOU MOLD YOUR HEAD UP AND WALK STRAIGHT ? ITS HOT! SOM 1, | WISH THEYD" STOP PUSHIN’ US @ SO HARD J

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682 POPULAR should have been refilled and charged im mediately. When the plates are sul- vhated, a long, slow charge is necessary to dissolve the sulphate, as much as four or five days being required in many cases. This explains why your battery station was so long in charging your bat- tery the last time, perhaps, and vou shouldn't have been sore about it. It was all your own fault. Impure water con taining minerals, when used in the bat- cery, also causes it to he very slowly charged, as the salts clog up the pores Sometimes it will not so don’t take a chance on distilled water. It is a good thing, when vou have driv en your car for a while and know about the average speed that vou like to drive, to go to the battery station and have them adjust the charging rate of the gen erator to suit vour driving habits. If, for example, you drive mostly in the day- time, very little at night, then the charging rate of the generator will prob ably be too high. If the electrical svstem is not regulated correctly and delivers more current than the battery can absorb, something is certain to be damaged by that This is generally the -posi tive plates of the battery, and opening the cells will show this condition by the burnt and loosened active material and the buckled and loosened plates. See Figs. 4 and 5. In this case, the charging rate should be lowered. If, on the other hand, most of your driving is done in the eve- ning, or if you must start and stop the mo- tor often, the charging rate should be in- creased to keep the battery properly charged. The following incident illustrates how the charging rate depends on the driv- ing habits of the owner. A car was used constantly, but was not started or stopped often. The battery could never be made to come up to more than half charge by means of the generator, and yet the battery and generator were in good order, as far as the service station could see. After riding with the owner for a few trips, a friend found the trouble. The automobile charging generator is de- signed to deliver its maximum output around the average driving speed, 25 to 30 miles an hour. Above this speed the charging rate begins to fall off rapidly. he generator on this car had been set, as are most of them, to give 10 amp. at 25 miles an hour, as the service man did not know, of course, what the driving habits of the owner were. As a matter of fact, according to the friend who diagnosed the in the plates charge ata anything but and excess. MECHANICS trouble, the owner didn’t know what 25 miles an hour felt like, except in traffic; his average speed was close to 50 miles an hour, and up to 65, just the range in which the generator output had fallen to the minimum. When the charging rate was adiusted to suit the owner’s driving range, the trouble disappeared. =" Then in the winter the demands on the battery are more severe. The car is harder to start, the lights are used for longer periods, and the battery is not quite so efficient in cold weather as in warm. It will often be found necessary to boost the generator output to take care of the additional drain on the bat tery. Have your service station do this. Be especially careful to keep the battery fully charged, not only for your own com fort in starting, but to prevent it from freezing. A fully charged battery will not freeze until the temperature reaches 95° below zero, but a battery that is only quarter-charged will freeze at zero, and a fully discharged battery will freeze at 13° above zero. Be as easy on the bat tery as conditions will admit. Prime the engine before starting up from cold, and turn the engine over a few times with the hand crank before stepping on the starter In summer, the main precaution to take is to keep up the level of the electrolyte, as evaporation is faster than in cold weather. When on a long drive, it is expedient to burn the lights in the daytime in order to prevent overcharging the battery and consequent danger of buckling the plates. Have the service station check up on the charging rate of the battery again, es- pecially if this has been boosted for the winter, and reduce it again to the proper rate for summer driving. It will pay you to take care of your battery, for new ones are an expensive item, and a good battery can be ruined in a very few months by lack of attention. Screen Holder for Shipping Tags In shipping poultry and eggs, where crates and cases are re- turned empty to the ship- per, the re- moval of tags and changing addresses is quite a task. This difficulty is easily over- come in the following way: A number of '. WIRE - SCREEN POCKET

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— — ” ae. 2 POPULAR MECHANICS 683 nieces of wire screen, 4 by 6 in. in dimen- sions, are creased and folded on the lines ndicated in the drawing. When tacked n place, one upon the end of each crate or case, they provide pockets for the easy insertion of the shipping tags, and a ingle tack through the eye of each tag holds it in place. To change the name and address, the commission dealer mere- has to remove one tack and replace it after reversing the tag and putting it back into the pocket.—G. E. Hendrickson, Ar- evle, Wis. Coal Ashes Save Fence Posts A farmer, having observed that the growth of grass and weeds around his fence posts held the moisture and caused the posts to decay at the ground line, prevented this trouble by tamping ashes into the ground for several inches around them. When building fences, he carried a barrel of coal ashes in his wagon, and, after a new post was driven, packed in the ashes. This prevents the growth of vegetation around the post and allows the sun and air to dry the soil quickly after a rain. Bicycle Headlight Any boy can easily make the dry-cell lamp shown in the illustration. Obtain a metal dry-cell holder and fasten an au- to parking light to the bottom. The ( CLAMPS WIRE TO _-” BATTERY / BATTERY BOX~ \, PARKING LIGHT Bicycle Headlight Made from Dry-Cell Holder and Auto Parking Lamp lamp should be of the type having a switch. The wires are brought through the cover and connected to the lamp. A pair of clamps are made of strap iron by means of which the dry-cell box is at- tached to the handlebars in the position indicated in the drawing. Floating Hunter’s Suit During the duck-hunting season the floating suit shown in the photo has been found very satisfactory by a California pl, Duck Hunter’s Novel Floating Suit Found to Be Very Practical hunter. It consists of a large inner tube, a pair of high rubber boots and a piece of sheet rubber, which is cemented to both inner tube and boots. This arrangement permitted him to float safely without get- ting wet and allowed free movement of the arms and hands. Dressing for Fishline A quick-drying dressing for fishlines may be prepared as follows: Mix equal parts of boiled linseed oil and gold siz- ing; apply this to the line in a moderate- ly thick coat. Dressing which will not dry as rapidly but which will resist the water as well is made by melting to gether 4 parts of paraffin and 1 part of rosin. Melt the paraffin in a deep metal vessel over a small fire, and add the rosin after the paraffin has dissolved. Care must be taken not to permit the fire to come into contact with the mixture. Al- low it to cool slightly and then coil the line in the vessel. Draw it through a piece of wet sponge held between the fingers. This will cool the mixture rapid ly and the line may then be stretched and polished with a wet rag.—A. E. Tetu, Ottawa, Canada.

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POPULAR SMALL HOLE ————— : —, ~ -[/ PIN- yy {| HOLE» ASBESTOS _- | \ WICKING 1! Wd eens —— —_— ~ 24" ~ Homemade Self-Blowing Alcohol Torches Produce Considerable Heat and Are Useful for Small Work Self-Blowing Torches For such work as soldering wires, etc., a small self-blowing torch will be found very useful. The torch shown in the up- per detail is made from parts of an old bicycle pump. The two tubes are held to- gether with the regular clamp supplied with such a pump. Screwcaps are fitted to the upper end of each contajner. A hole is drilled through one of these clamps for 4-in. copper or brass tubing, which extends nearly to the bottom of the container, and has a wick pulled through it. A cap is provided on the open end and a length of chain, soldered to both the cap and the container, prevents the cap from being lost. The open end of a dust cap trom an auto-tire valve is cut off at an angle and is soldered to the screw cap of the other container, this cap having a hole drilled through it. \ pinhole ts drilled in the upper end of this cap, as indicated in the upper right-hand detail. MECHANICS A length of 4%-in. tubing is sol- dered inside of the cap and is bent to extend to within ™% in. of the bottom of this container. A wick is also pushed through this tube. Both containers are filled with alcohol, the wick is lighted as shown and the torch is held at such an angle that the lame heats the end of the adjacent cap. This causes the alcohol inside to evap- orate and the gas thus formed has no other outlet than the pinhole, provided the screwcap is turned down tight. A rubber washer should be used under each screw cap to assure air-tight seating The containers are adjusted so that the flame will effectively heat up the cap when the torch is be- ing used with the result that a constant pressure will be main- tained. The lower detail shows another small torch, which oper- ates on the same principle but is easier to make. It consists of the body of an old oilean provided with an air-tight cap. A length of copper tubing is bent ee shape shown and is fii wicking. The ends of the tubing are soldered into two holes drilled in the side of the can, and the wicking should pro- ject far enough to take up alco- hol, with which the can is filled. A small pinhole is made at the point indicated. The coil of tub- ing is first heated with a match to produce pressure inside, and as soon as the flame starts, this pressure will be maintained, since the forward part of the coil is kept constantly hot. asbestos Stopping Spare-Tire Rides Many boys have the hab- it of stealing rides on autos by hopping onto tre spa re-tire holder at the rear, which is a very dan- gerous prac- tice. To pre- vent this one auto owner bolted a short length of spiked guard, such as used on fences, to the in side of the tire holder as shown in the photo, and found it very effective.

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—eerenme <5 ——~ ) op | | He : ‘ ' = : | LS H i- } \ 0 Za x — AD % =, i o- J Wes 2? ’ sy ~ Le & aS oxen —, All Shop Notes published in 1925, in book form—Fifty Cents—from our Book Department How to Treat Plastic Paint By J. S. HAGANS

PLastic paint is a gypsum product this fact does not necessarily limit its marketed under the name of tex- uses for building purposes, although it is tone, which has some of the characteris- here that its application will perhaps tics of the gesso that is now having a have the greatest appeal. This material renaissance among home art workers. comes in standard-size 10 and 25-lb. This material, which can be used for packages in the form of a white powder. obtaining much broader effects just as well as it can for the finer gesso appli- cations, is to be had at most paint stores and building-supply sources. While pri- marily produced as an architectural material,

Fig. 1, Mission Finish; Fig. 2, Paper- Stipple Finish

It is not a plaster in any sense, but a true plastic paint. The addition of lukewarm water and coloring pigment, if desired, is all that is necessary to its application with an ordinary = paint- brush. One pound of

Scroll

Fig. 3, French Finish; Fig. 4 Finish

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686 POPULAR MECHANICS sq. yd. of surface, or about as much as ordinary oil paint. It can be applied over any suriace and a wide variety of charming and distinctive effects are with- in reach of any reasonably intelligent per- son capable of using a paintbrush. the material will cover approximately 1% The richly at- tractive stone and rough - surfaced wall effects one sees in window ‘backgrounds, wall finishes and sur- faces on fixtures, polychrome or otherwise, if they haven't been obtained through the use of textone, can be. Therefore, the storekeeper, the home owner or the artistic person who wants to polish up something in an original way, will find in this material a very flex- ible medium that is susceptible of all sorts of manipulation. Aside from the material itself, the only thing needed in the way of equip- ment is a paintbrush, large or small, as the surface to be worked upon may demand. Use a 12-qt. water pail and add to the powder lukewarm water, from which the chill has just been removed, in the pro- portion of 1 pt. of water to 1 lb. of tex- tone. Do not, under any consideration, attempt to mix it thin like calcimine. Allow the mixture to stand for about 30 minutes, after which it is ready to apply. If a one-coat tinted effect is desired, this mixture can be colored to certain shades. The following pigment colors ground in oil, and slightly thinned with turpentine, or dry colors dissolved in water, can be safely used: For red, use Venetian, In- (ian or permanent reds; for browns and tans, use raw umber, burnt umber, raw sienna, burnt sienna; for yellow or creams, use vellow ocher; for blue, use cobalt or ultramarine blue; for green, cobalt green; for black, use lampblack or dropblack. Fig. 5, English Finish; Fig. 6, Stipple Finish, Using Brush; Fig. 7, Brush Finish Avoid Prussian blue, carmine and aniline colors. While chrome green and yellow can be used, the decorator must handle them carefully and limit the quantities. [t is important that the pigment first be dissolved and then added to the pre- viously mixed material. It is necessary that sufficient tex- tone should always be prepared to complete the job, in order to insure the same color. Inci- dentally, it would be well to experi- ment with the color before applying to the surface to be worked, as it may be too dark or too light when dry. In either case, the proper effect can be ob- tained by adding either more textone or color, as required. This plastic paint may be successfully applied over any surface, if the user is careful to remove from it all dirt, grease or efflorescence, so that it is clean and dry. Generally speaking, it will be found advisable to give the surface a coat of size, which is furnished with the material as it is bought, and this should be allowed to dry for six hours after application. For finishing over sheet-rock p'‘aster- board, or any of the other varieties of wallboard, be sure that all the joints and nail heads are completely concealed and that the surface is in a level plane at the joints. Textone cannot be successiullv used over gloss oil or varnish sizes, and their use should be avoided for this work. On new or old plastered surfaces, not decorated, the plaster must be at least two months old. If the plaster finish is found to be unusually soft or absorbent, proceed as follows: First, get a good grade of floor varnish and mix with an equal part of turpentine. Then mix this liquid with textone in the proportion of 1 Ib. of the powder to 1 pt. of liquid, and + Te. ey

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ale POPULAR MECHANICS 687 apply as a sizing coat. When this is thoroughly dry, remove the sharp “nibs” with sandpaper and apply the previously prepared material. Where the plaster finish is normally hard and not too ab- sorbent, sizing is not required. A hard, smooth plaster surface is sometimes difficult to cover. In this case, apply a preliminary coat of textone, well brushed out; allow this to dry and then apply the regular. preparation. The plastic paint may be applied over a coat of brown plaster after it has been darbied to a _ true surface, troweled smooth and sized. For application over painted surfaces, scrape off all loose and scaling paint and fill cracks and holes to a level surface. When dry, sandpaper smooth and color patches to match surrounding surface. Great care must be taken to see that all grease, dirt or wax is thoroughly re- moved. If the surface, after being thor- oughly cleaned, looks glossy or enameled, kill gloss with a 10-per-cent solu- tion of sal soda or washing powder and hot water. Rinse with clear water and apply the plastic paint without sizing. Calcimined sur- faces must be washed clean, so that no color re- mains in the cor- ners around the trim, after which directions for cov- ering wallboard or plastered surfaces may be followed. If the under sur- face has a_ high gloss from _ pre- vious sizing, treat as suggested for gloss-paint sur- faces, and apply the textone without us- ing any sizing. Wherever possible, wallpaper should be removed and the under surface treated ac- cording to whether it is of plaster or wall- board. If the paper cannot be removed, it must be securely bonded to the surface. Remove any loose parts or paste them down. Wallpaper that has been applied with paste that will soften in 8 or 10 hours must be removed. Wallpaper that contains water-soluble dyes will discolor the material and must be removed. A damp cloth rubbed over the surface of the paper will be discolored by such dyes. Roughen a high-gloss wallpaper with Spanish-Palm Finish, Made by Means of the Back of an Ordinary Kitchen Spoon sandpaper. Wipe free from dust and dirt and apply the plastic material directly. On glass, metal or wood, remove the grease and wax finishes and kill the varnish or glossy surface by an applica- tion of a 10-per-cent solution of sal soda or washing powder in hot water. Rinse with clear water. These surfaces should not be sized. To apply the textone, use a clean wall brush, which is similar to a calcimine brush, and lay on a coat to a uniform thickness of 4s or 4% in. After it has set a little, until tacky or drawn up, stipple with a wall stippling brush, as in Fig. 6. Other effects can be obtained by the use of an ordinary paintbrush, Fig. 3, either slapping, pushing or dabbling it with a straight or side motion. A sponge or ball of crumpled paper, used as in Fig. 2, will vary the texture. Two persons work to the best advantage over large surfaces, one applying the material as the other does the stippling. As hardened plastic paint of this kind is insoluble in water, do not allow it to spatter or harden on woodwork or trim. Wash them off at once with warm water and a sponge. Where the trim is in place, it is best to go over it with a rag moistened in boiled oil or kero sene, to make re- moval of spatters easy. Pails, tools and brushes should be kept clean. Do not let the material harden on them. A moderate tem perature should prevail in the room. While applying the paint, close the doors and windows to avoid drafts, opening them after appli cation to permit a free circulation of air. Build a fire in cold weather. When the coating has dried, place a piece of sandpaper flat on the surface and rub slightly. This enhances the tex- ture by removing the rough or pointed edges and making it stand out more prominently. Plaster-molding effects are obtained by the simple process of cover- ing ordinary wooden moldings with the textone. The illustrations show a number of methods of finishing the material, and these are as follows: Fig. 1, Mission fin-

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688 POPULAR MECHANICS ish; the material is applied with a calci- mine brush, and the texture obtained with a small brush worked over the textone with a circular motion. Use the palm of the hand to obtain smoothness where de sired. Fig. 2, paper-stipple finish; the texture is obtained with a ball of wadded paper. The effect is a little coarser than if a stippling brush is used. Fie. 3, French finish; texture obtained by firm downward sweeps of a small whisk broom; sandpapering the surface, when dry, will soften the effect somewhat. Fig $+, scroll finish; the material is worked with the tips of the fingers in a circular motion. If the effect is too coarse, smoothing with the palm of the hand, or sanding when dry, will soften it. Fig. 5, English finish; the texture is obtained with a wide scraping knife or piece of tin, to imitate the effect of old tool mark VIM MLZ TIGHT FIT2 ------- « 2ROUND STOCK Tool for Transferring Measurements from an Inside to an Outside Caliper, and Vice Versa Caliper-Setting Tool It takes considerable skill to transfer sizes from an outside caliper to an inside caliper, and vice versa, owing to the small point of contact between the two tools. However, as it is a simple matter to set calipers against a flat face, the tool shown in the illustration is most useful for this work. Two pieces of 3¢-in. round stock are cut down to half their thickness on opposite sides, and carefully drilled and reamed in the center to fit a length of “e- in. rod bent to a right angle at one end. One ot the pieces is a sliding fit and the other a tight fit on the end of the rod. Supposing a hole is to be drilled to fit a shatt; the outside caliper is first set to the shaft, then the setting tool is used to du- ings. Fig. 6, stipple finish: material stippled with regular painters’ stipple brush. This finish can advantageously be sanded when dry. Fig. 7, brush finish; the material is here applied with a wall brush, then stippled lightly with a wad of crumpled paper and finally brushed down with a large calcimine brush. Fig. 8 Spanish-palm finish; textone applied with a wall brush; texture obtained with the back of an ordinary kitchen spoon The palm of the hand can be used to soften the effect, rubbing it over the marks made by the spoon, and this is sug gested. Unless otherwise specified for these effects, the material is first applied with a large calcimine brush. The effects obtainable are limited only by the ingenuity of the worker, and with the foregoing instructions he can easily work out new effects. plicate this measurement, as shown, and the inside caliper may be accurately set against the flats at the opposite ends of! the cut-down pieces. This operation is of course, reversed when setting outside calipers to an inside setting. Lubricating Wagon Wheels It is a rather disagreeable task to lubri cate wagon wheels as the wagon must first be jacked up and the nuts on the axles must be removed. While performing this I have often wondered why wagons were not equipped with modern time and labor - saving lubricat- ing devices, so I set about to adapt the wagon wheels to the grease gun. Adapt- ers of the kind used on auto - spring bolts were obtained from a junk dealer. Four short lengths of pipe were tapped to take the adapters and a hole was drilled in each hub so that the lengths of pipe could be driven in snugly. The adapters were then screwed down into the tapped ends, as shown in the drawing, and it was then a simple matter to use a grease gun C. M. Wilcox, Torrington, Conn. ——— —_

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*..

POPULAR MECHANICS 689 Rapid Stage-Erecting Device \ simple, effective and safe device for nidly putting up stagings in the erec- n of buildings has been worked out by \laine carpenter. It consists of two rt lengths of scantling and four iron rap hinges. The larger stick is 4 in., and the second slight- smaller. The first is used as e beam upon which the stage ay 3

Simple Stage Brace, with —_ ay Arm and Strap Hinges, Speeds Up Building-Stage Erection and Re- moval, and Is Entirely Safe boards are resting. <A large hinge is fas- tened to both ends of this stick. Half of each hinge hangs loose so that it can be attached to the side of a building and to the scaffolding. The smaller piece is fas- tened to the larger by a third hinge, and to the building in the same way as the hig stick, by means of the fourth hinge at the building end of the stick. This forms a supporting brace for the scaffold. hree nails are driven into the wall, and a like number into the scaffolding, allowing the holes in the hinges to pass over the heads of the nails. Then, as the weight of the sill rests on the hinge, it is pushed down and the nail heads act as buttons, lastening the hinges securely to the build- ing and scaffold. The side brace fastens in the same way. To release it, simply raise and let the nail head go through the large end of the hinge hole—Sam E. Con- ner, Auburn, Me. Connecting Pipes with a “Dutchman” An excellent “dutchman” can be made, for straight work on large flanged-pipe lines that fail to meet and are too close to allow the use ofa nipple. If flanges are not immediately available for making up the nipple, take a piece of the next size irger pipe. Face the ends off in a lathe, making the length of the dutchman the

same as the distance between the two flanges that will not meet. Cut two gas- kets from %e-in. sheet packing and force the lines apart so that the dutchman, with a piece of packing on each end, can be squeezed into the opening. Pull the two flanges tightly and evenly together all the Y pani 7 oo . ~ This makes way around, using long bolts. a very satisfactory job for medium steam and water pressures. Removing Lead from Automatic Pencil It is a rather laborious job to drill the lead out of a steel pencil when it becomes lodged in the point, as drills small enough are not always at hand and there is also danger of injuring the tiny lugs that hold the lead. The simplest way is to hold the point of the pencil in an alcohol flame for a few seconds while exerting pressure on the lead by turning the feed. The lugs will be expanded so that the lead can eas ily be forced out. Care should be taken not to hold the pencil in the flame too long, as heating it too much may injure the point.—L. A. Krider, Hatton, Wash @ Wallpaper can be washed with a soit cloth saturated with benzine; neither pat- tern nor color will be affected.

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690 LOOP ENDS WIRE BINDING _IRON ROD BEND UPWARD Hs METHOD | | | | OF BENDING Handy Tool tor Pulling Lengths of Pipe from the Stock Rack Removing Pipe from Racks The photo shows a handy tool used in a pipe warehouse for pulling out lengths of pipe from racks too high to reach eas- ily with the hand. No machine work is necessary to make the tool, the work be- ing a simple bending operation. A length of iron rod, about %-in. in diameter, is bent round to form two loops m the cen- ter, with the ends of the rod pointing in opposite directions. An upward bend is given the loops to bring them in line ‘. as shown, after a - which the ends of , the rod are bound in hha Rae three places with : wire, near the loops, = ' ee in the middle and “> “4 POPULAR MECHANICS Starting a Stiff Engine After tightening up the connecting rox of an engine, or possibly the crankshaj; bearings, it often occurs that the engi: cannot be turned with the starter. T! condition may be discouraging, but if t! owner of the car has an extra battery o can borrow one temporarily, it will be pos sible to turn over even a very stubbor: engine. To use the extra battery, con nect one side to the ground and the othe: side to the terminal of the starting moto duplicating the connections as made wit! the regular battery in the car; in othe: words, connect the batteries in parallel s. that the voltage will be the same but th: amperage doubled. The extra battery can be placed on the running board of the car, and temporary connections made t. the ground and to the starting-motor ter minal. This method is used regularly b a mechanic of a small service and: sale station. Also under other adverse con ditions, as during extremely cold weather, with tight pistons, or a gummed motor. the method will prove helpful. Ridding Deep Well of Foul Air A resident found it necessary to clean out an old, deep well. Upon investigation the air at the bottom was found to be fou! and unfit to breathe Just how to get rid Hl of this air was the . ee problem until a — , neighbor suggested ~ rigging up a_black- again near the end. The finished length of the tool is about 4 ft. To pull a piece of pipe from a rack, Ba A the loops are passed £ over it and the oa paaee handle pulled. This PE Pa, binds the loops on the pipe and the lat- ter is pulled out. If the pipe is short, it can be lowered bodily to the floor. \ Long pieces are pulled out of the rack until overbal- anced and then let down eas- ily to the floor. @ Rose reamers should never ~ be used for any other metal . than free-working steel, and as then only under the best working conditions. Forge Blower Used for Sup- plying Air to Workers in Deep Well smiths’ forge blower es inthemanner shown. The blower was set up alongside oe the well curb and se- cured with a guy rope and stake, as in- dicated. A piece of fire hose was clamped around the nozzle wes and dropped to with- ~“ ° ina few feet cf the a A bottom of the well, “ so that it would hang just A above the worker’s head and yet give him enough room to work. The flaring end of a large tin funnel was used as a discharge nozzle to distribute the air in all directions. With an operator turning the blower crank slowly, the cleaner went to the bottom of the well and * 74 oxy

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n- an On ym yu . id he a ec k- er By er e- 1y n- of >< le h- 1e

POPULAR MECHANICS 691 ere was no difficulty in supplying him th plenty of fresh air—L. B. Robbins, irwich, Mass. Substitute for Draw-Filing Draw-filing of cast-iron cylinders, which a tedious job and produces uncertain sults, can be done better by the use of nurling tools. The wheels, costing from 15 cents up, can be obtained for all sorts f fancy finishes. They give a uniform nish, and take only half the time required i draw-filing. This method can also be ised on cylinders for finishing presses and milar classes of textile machinery.—H. Toombs, Chicago, Ill. Mixing Concrete in the Wheelbarrow A simple and easy method of mixing concrete by hand in a wheelbarrow is shown in the il- lustration. Fig. 1 shows a batch of dry material con- sisting of four shovelfuls of gravel, two of sand and one of cement. Fig. 2 shows the first operation, work- ing the material to the front of the barrow, with a round - pointed shovel. Fig. 3 shows the same batch after it has been worked back again in the same way and some water has been added. The ma- terial is worked to the front again, leaving it in the position shown in Fig. 4, and then again backward. It is now thor oughly mixed and will keep itself in the position shown in Fig. 5. The writer has used this meth- «| and found it entirely satisfactory.— H. H. Siegele, Emporia, Kans.

@To prevent exposed black pipe from rusting, cover it with a grease made of 1 lb. lard, 1 oz. gum camphor and 1 oz. black lead.

Neat Wooden Boxes along the Roadside Hold Farmere’ Cream Cans Boxes for Cream Cans Instead of following the usual custom of dropping the cans at the roadside to be jostled or stolen, one Texas creamery has had several hundred wooden boxes built and placed along the road. The boxes hold three 5-gal. cream cans, and when the truck drivers return the empty cans, they place them in the box and close the lid. The'system has practically stopped complaints and theft, and is a method en- dorsed by the road commissioners. Each box is 18 in. wide, 40 in. long and high enough to take the cans. The cover is hinged and the outside bears this message, “Leave Cream Cans Here.” Keeping Moss from Choking Irrigation Canals The aquatic moss which grows in the smaller lateral irrigation canals during the summer months, sometimes to such an ex- tent as to interfere seriously with the delivery of irrigation water, can be kept down by dragging a heavy iron chain along the bottom of the canal. Two two horse teams are used. One team is at tached to each end of the chain and the two teams are driven along the banks, one on either side. The dragging is done about three times a week during the en- tire irrigation season. The work can be done whenever convenient, without shut- ting the water out of the canal.

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) a!) og 4 ow “Regge . g ihe} | NE of the main features of a home is the walk leading to the’ entrance door. It is the first thing that meets the eye of the person entering. If the walk is neat and well kept, the impression is bound to be fair; if it is poorly laid and ill maintained, the impression is likely to be a bad one, notwithstanding the fact that the exterior of the house may be beauti- ful. Not alone the front but also the side walks and the garden walks, if laid in an attractive manner, will go far to- ward making the house good to look at. It must be said at the beginning that the main purpose in writing this article is to show how to construct a well-built walk other than the ordinary concrete side- walk, and to illustrate various patterns and different materials which may be used to good advantage. The materials tor the construction of a decorative walk depend a good deal upon the location of the town in which the walk is to be built. For example: in cer- tain towns slate is available, in others it is not; in some brick may be purchased at a very reasonable figure, in others it will be found to be quite expensive. Thus, where cost is an important factor—and it generally is—the material should be se- lectéd from among those most readily available in the town. There are four materials which lend themselves to decorative-walk construc- tion, and they are stone, brick, tile and 692 concrete. With stone, some very attrac tive walks of the flag-type may be built Flag walks are of a rather informal ap pearance when laid with wide joints so that the grass grows between the stones. and are more suitable for gardens than for the front walks to homes, but where a rustic effect is desired, such as the walk for an English-cottage-type house, set in rather heavy foliage, nothing blends into the picture so well as a flag walk with the flags about an inch apart and grass grow- ing between them. Brick and tile present a more formal or citylike appearance than stone, al- though brick may be laid with wide grass- grown joints to give a garden-walk ef- fect. It is more often, however, laid in a simple pattern and the joints filled with cement grout. Ordinarily the joints in brick walks are not greater than 46 or 4% in., although when a grass-grown brick walk is desired the joints should be at least %-in. wide but not more than %& inch. Tile used for walks is of the kind known to the trade as quarry tile. It is not quar- ried, however, as its name might indicate but is made of burnt clay in the same man- ner as brick. It comes in sizes ranging ordinarily from 4 by 4to8 by 8in. It may sometimes be had in larger sizes than &- in. squares, but seldom smaller than 4 by 4-in. The thickness may vary from % to 1 in. depending upon local kiln practice. Concrete is a good material for orna- oe,

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a annie tn re POPULAR MECHANICS 693 ntal walks in that it may be used to ke concrete flags or tile, and thus this terial may be used in localities where genuine is not available. One advan- of concrete is the fact that it can id everywhere. With concrete flags ry attractive effect may be obtained ‘oloring the pieces. All that is neces- is to add some mortar color to the xture when it is made up. A varicol- | walk may be built up by using units several tints. This makes a very at- tive walk provided the colors are sub- ed and blended harmoniously. Ve will first take up the construction of ilk, of which there are two main types, with a concrete base, and that with- Where climatic changes are con- erable no walk should be built without oncrete base, lest it be destroyed by be- uplifted due to the action of frost; in warm climates, where heavy frosts not encountered, the concrete base be dispensed with. Fig. 1 shows a section through a brick k with a concrete base. Brick walks, the way, should always be built with a

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POPULAR MECHANICS Next the con- tamped firmly and solidly. crete base is applied between the forms, as shown in the sketch. The forms consist of 2 by 4-in. lengths held in place by stakes. The stakes are made high enough so that an additional 2 by 4-in. piece may be attached and used as a guide for lay- ing the brick. The concrete used should be a 1:3:5 mix, and should be allowed to set for 24 hours before the brick are laid upon it. Before beginning to lay the brick, a thin layer of fine bank sand, about % to \% in. thick, should be spread on the concrete. This sand cushion will take up all the little unmevenesses in the surface of the concrete and make the laying of the brick easier, in addition to providing a cushion for the walk. The brick are laid to the desired pattern on the cushjon of sand, and the joints are then filled with grout. This grout is made by mixing one part of Portland cement with one part of fine bank sand and adding enough water to make the mixture flow easily. In filling the joints take care that any grout lying on the edge of the brick is quickly re- moved with a wet rag, for after it sets, it will be difficult to scrape off and the walk will not look well. At intervals of about 18 or 20 ft., the joints should be filled with tar or asphaltum in order to provide an expansion joint. Another way oi grouting a walk would be to fill the joints with a dry mixture of cement and sand and then sprinkle it with water. The first method is to be preferred, however, for, though it requires a bit more care to pour the grout than to pour the dry mixture in the joints, the effort is well repaid by the assurance that the entire joint is filled with concrete instead of the possibility of having the top half filled with con- crete and the bottom half with a dry powder. Where walks are laid without a con crete base, the construction is shown in Fig. 2. This is practically the same as for the construction with the concrete- base walk except that the concrete is omitted and the sand cushion laid directly upon the cinders. The sand _ cushion should be made % to 1 in. thick. Walks with only a cinder base are not grouted, but are intended for use where it is de- sired to allow grass to grow between the joints in the walk. Many beautiful patterns may be laid in — ee a

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- al POPULAR MECHANICS k walks. Brick lends itself especially vattern work due to the proportions he units, the ordinary building and ng brick being about 2 in. thick, 4 in. e, and 8 in. long. Thus, allowing for a rtar joint of suitable width, two thick- ses of brick make one width and three -knesses make one length. Thus, vari- arrangements of width, thickness and eth mav be made. There are two ways ing brick walks; the first with the k flat, and the second with the brick lon edge. Laying the brick flat, fewer ck are required for a given area than tting the brick on edge, but the laying be found slightly harder. Flat-laid k adapts itself better to wide, grass- ed joints than does brick laid on edge. may be taken as a commonly accepted ile that brick laid on edge should always e laid on a concrete base, and the joints led with cement grout. 3rick laid flat, vever, need not be laid on a cement ise and need not have the joints grouted. good width for the ordinary front walk ibout five bricks wide, or approximate- $2 in. A four-brick-wide walk (about in.) may also be used if the first width ry NMVUUUANTOQOTTNONNE 695 is too great. Garden paths and winding lanes through shrubbery may be three bricks wide. In Fig. 3 is shown the southern style of walk. This consists of | a regular pattern. In Fig. 4 is variation of the southern style, which calls for the breaking of the joints in each i made flat in shown a brick laid row. The brick could also be. laid with the length of the brick parallel to the length of the walk, instead of perpendicu lar to it as illustrated. Fig. 5 illustrates the hearth pattern Here two bricks are laid parallel, with alternate pairs at right angles \ varia tion of the hearth pattern is shown in Fig. 6. This consists of laving the brick at an angle of 45° with the border of the walk instead of parallel to it. In this, the brick at the edge of the walk must be cut in order that the line at the edge of the walk be preserved. Fig. 7 is the same pattern as Fig. 4, except that a dia mond design is worked into it by the use of different-colored brick. In laying a walk in this pattern it is not well to have too great a contrast between the brick If the two colors are just differ- colors.

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ent enough so that the diamond design is only slightly discernible, the best effect will be obtained. The herringbone pattern shown in Fig. 8 is a neat one, and is quite popular. It is comparatively easy to lay and less .cut- ting is required than for the design shown in Fig. 6. In Fig. 9 is shown the herring- bone pattern with the brick laid on edge. Laid on a cement base, this pattern with the joints grouted, provides an especially strong and durable walk. Edge-laid brick, illustrated in Fig. 10, makes an easily built and strong walk. The brick can also be laid with the joints POPULAR MECHANICS 7s We: ie broken, as shown for the flat-laid brick in Fig. 4. In Fig. 11 is illustrated the basket-weave pattern, somewhat similar to the hearth pattern shown in Fig. 5, °x- cept that the bricks are laid on edge, and that three bricks are used instead of only two. Fig. 12 is a combination of the basket-weave and the hearth pattern Fig. 13 shows a diamond design worked into an edge-laid walk. A little study will show that this design differs considerably from the diamond design shown for a flat- laid walk in Fig. 7. A combination brick and tile walk is illustrated in Fig. 14. In some cases, it is desirable to have

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POPULAR. MECHANICS 697 borders for the walks, not only for the .dded decorative effect, but because, with the pattern used, small pieces are left at the edge and a border is required to hald them in place and prevent their being chipped out. Thus, while the design hown in Fig. 14 would not require a border, that illustrated in Fig. 9, the her- ringbone walk with the brick laid on edge, would need a border in order to keep the small triangular filler pieces from being knocked off the edge. Figs. 15 to 19 illustrate borders of various de- signs which may be used. Figs. 21 to 23 show various ways of building up a corner in a brick walk. Some patterns for quarry-tile walks are shown also. Fig. 24 illustrates a walk with the joints laid regular. A va- riation of Fig. 24 would be to break joints similar to the manner used in. the flat- laid brick walk shown in Fig. 4. Fig. 25 shows a walk with the tile laid at an angle of 45° with the edge of the walk. This is a pleasing design but the cutting of the tile for the edges is quite a task, and a good many will be wasted due to their failing to cut properly. In Fig. 26, two different sizes of tile are used, as is also the case in the pattern shown in Fig. 27. As a great many sizes and colors are ob- tainable in this material, some very beau- tiful patterns and color schemes may be worked out. It should be borne in mind, however, that of the several types of walk described in this article, those built of quarry tile are the least durable, and are more suited to interiors and semi- protected places than to open spaces where they may be subjected to the con- tinuous action of the elements. Perhaps the most decorative walk of all is that made of flags. Flags are large stones about 10 by 24 in., or thereabout, although they may run in size from 6 by 8 to 12 by 36 in. They may be laid on a cinder-and-sand base without fear of great distortion, and they appear particu- larly attractive when they are laid about 1 in. apart with grass between the joints. In some localities stones of different colors are ob- tainable and they may be used to ad- vantage in laying a walk in a desirable color scheme. A combination of reds and browns, or greens and blues, or any other colors which do not clash, is very pleasing. © Keystone View Co, Rock Drill Run by Automobile Engine, Which Is a Mounted on Truck Where stone is not readily obtainable. concrete flags may be made. A gang mold for making concrete flags is shown in Fig. 28. Here three flags can be made at a time, two large and one small, al- though the number, size and shape may be varied to suit the requirements of the job. The mold consists of two planks fastened together with cleats to form the bottom, and enough cleating nailed around the edges to give the desired shape and size. The flags are molded in the same manner as any other kind of con- crete casting. They should be about 3 in. thick, and it is well to reinforce them with chicken wire, especially the larger sizes. When applying the wearing sur- face, color effects may be obtained if a little mortar color is added. Fig. 29 shows a walk built of field stone; this is, as its name implies, a walk built of stones of random sizes and shapes, fitted together in a kind of crazyquilt pattern. The stones are laid with rough edges, just as they are picked up in the field. This is an ideal rustic walk for heavily wooded places. Fig. 30 is a simi- lar walk with the edges cut to a line. The walk shown in Fig. 31 is what is known as random rectangular, that is, the stones are rectangular in shape but of random sizes, and are fitted together as shown in the pattern. A variation of the random- rectangular pattern is shown in Fig. 32. Here the stones are of one width in the respective rows, but of varying lengths. Figs. 33 and 34 show designs obtainable by the use of flags of two different sizes, and in Fig. 35 is illustrated a walk in- volving the use of three different sizes. Fig. 36 is a diamond pattern which may be worked into a flag walk somewhere along its length or at a crossing. There are an infinite number of pat- terns for the different materials men- tioned in this article. Anyone with just a little ingenuity can develop a host of patterns, using those illustrated as a basis upon which to work. Auto Engine Runs Rock Drill One might mistake the ve- hicle shown in the photo for a two-way automo- bile, but it happens to be an ordinary truck with an extra engine mounted on the rear. This is used for the purpose of running rock drill, which is geared to it.

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698 POPULAR Handy Shop Scrap Box To keep the floors and benches of the shop clean, a large concern is using scrap Shop Scrap Boxes Attached to Concrete Posts boxes attached to the concrete pillars on each floor. Loose boxes were formerly placed at intervals around the shop, to be emptied at the end of each day, but very often they would be moved to suit some person's convenience, with the result that the man detailed to empty them would have difficulty in locating them. The shape of these boxes is clearly indicated; they are constructed of sheet metal and are held to the posts by means of a screw and washer on each side, the screws be- ing turned into wood plugs driven into the concrete. The truck used to carry away the scrap is backed up to touch the post under the box, and the latter is then liited by the handle in order to allow the contents to drop into the truck. Testing Galvanized-Iron Wire Many farmers send for samples of wire fencing before placing an order. Often two samples arrive that appear to be the same-gauge wire and, as far as looks go, gaivanized alike. Usually the farmer rushes his order off to the manufacturer quoting the lower figure. This, however, might not happen if he realized that the life of the fencing depends on the thick- ness of the protective coating of zinc, and MECHANICS tested the samples in this respect. Such a test may be made in the following way: Leave a sample of the wire in a saturated solution of sulphate of copper for one minute. After wiping it clean, replace it in the solution for another minute. Re- peat this process four times, and if the wire keeps its black color, it is proof that the zinc has not been eaten away and that the galvanizing has been well done. However, should the wire appear copper- colored after the second or third immer- sion, the coating is too thin to make the wire economical for fencing purposes. Most farmers have sulphate of copper, or blue vitriol, about the farm, as it is used widely in spraying solutions. A saturated solution is made by dissolving as much of the crystals in water as the latter will take up.—C. M. Wilcox, Tor- rington, Conn. Ball-Bearing Adapter Bearings from old automobiles, tractors, etc., can be used to advantage for line- shafts and countershafts on various sorts of machinery. To mount the bearing on the shaft, a sleeve is made from steel tub- ing of the proper size, which requires the least labor to machine. The sleeve should be a close sliding fit on the shaft and a press fit in inner race; the bearing is made to project from the bearing race approxi- mately 1% in. OUTER CASING-. on each side, is turned COVER ~~. veovwen _ slightly taper- q 1} cup ing at each SLEEVE, st A , end, and threaded and slotted into three or four sections in the tapered parts. Two nuts are pro- vided to fit the tapered ends and, when tightened, will clamp the bearing sleeve firmly to the shaft. The outside casing for the bearing is made from a piece of cast-iron bushing stock, which may be obtained from an iron foundry. The casing is machined as shown, being made a light press fit for the outside of the ball-bearing assembly. Re- cessed sections are provided at each end of the casing in which are fitted the steel covers, made of \%-in. mild steel, these covers being held in position by machine screws. To exclude dirt and retain grease,

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POPULAR MECHANICS ‘wo cup-shaped pieces, made of cast iron, are attached with machine screws. Care hould be taken to select ball-bearing as- emblies that are in first-class condition, to assure their satisfactory service. The sutside casing is provided at two opposite points with small depressions to receive the points of the handscrews, and a com- ression grease cup should be fitted to sup- ply the necessary lubricant.—Edwin Kil- burn, Spring Valley, Minn. Detachable Knob for Jigs and Fixtures Many times the jig, fixture and fool de- igner is confronted with the need for a letachable knob or nut, not only for the purpose of removal so that the work or another piece can be taken from the stud, but also as a method of setting an ad- justment that can be kept free from tam- pering. The drawing shows a nut of this type that has been used with satisfactory results. The fixture stud is machined with flats on opposite sides and the knob, which can either be cast or machined, has a slot in the side so that it will fit over the stud. Fig. 1 shows the construction of such a knob and its use in a fixture that holds a small pulley while drilling an oil hole. The stud is threaded and screwed into a hardened-steel nut at the back of the jig. By removing the slotted knob the work can be slid on the stud and the knob then replaced and the screw tightened. Fig. 2 shows its use on an adjustable V-block fixture. The object in having the knob removable in this case is to prevent altera- CAST-IRON KNOB a 8 stud SMALL PULLEY ON JIG, TO BE DRILLED FOR TAPPED HOLE IN nuUB MARDENED-STEEL NUT Fic.2 ADJUSTABLE “Vv"-BLOCK STUD FOR REMOVABLE KNOB a Detachable Knob Facilitates Handling of Tools, Jigs and Fixtures tion of the adjustment as set in the tool room.—W. Burr Bennett, Honesdale, Pa. 699 Trailer for Gasoline and Oil Drums In moving from place to place, contrac- tors are often inconvenienced by the ne- cessity of loading and unload- SS. SS Trailer for Gasoline and Oil Drums That Will Be Found Useful to Contractors ing gasoline or oil drums onto and off trucks. This difficulty can readily be over- come by providing a trailer like that in the drawing, which was made for the pur- pose. It consists of a bowed axle con- iorming to the curvature of the drum§, and a frame -nade of pipe. In use, the frame is held in a vertical position against the drum, and the hooks on the frame are engaged with the end edges of the drum. The trailer is then leveled and attached to the truck.—G. E. Hendrickson, Argyle, Wisconsin. Keeping Canal Banks Free of Grass One irrigation district, where Johnson grass along the canal banks grows down to the edges of the water and causes sand and debris to accumulate and seriously re- tard the flow, has found that the grass can be kept down economically by pas- turing herds of sheep and goats along the banks. The animals are confined by portable fences, which can be moved along the Lanks as fast as the grass is eaten off. Several other methods tried were either unsuccessful or too expen- sive—Ivan E. Houk, Denver, Colo.

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700 Using Broken Steel Fence Posts Wherever steel fence posts have been in use you will find some have been broken off or bent out of shape and are consid- ered useless. How- ever, the drawing = aa = oe a 3) : we =f] “ie O rer ar anes wi er bn in a) y pa ny a) M Fg Ny oul / han 4g / : i V"Gy Y J Nas - | A AOL? Wt; S we y 18" lint i ” ” w/e, y! “ora. LAD Short Lengths of Old Steel Posts Keep Wire Fence Taut and Prevent Animals from Ruining It shows a good use for them. Cut them in- to 18-in. lengths with a hacksaw or cold chisel. In this way you will get four or five pieces from each post, according to its length and condition. The pieces either have holes in them or a hook of some kind where wires have been fastened, except the part that has been in the ground. That part should have a small hole drilled through one end. With a sledge or maul drive one or two of these lengths between each of the line posts along the fence; fasten the bottom wire of the fence to one of the holes or hooks near the end of the post and drive it down until nearly all is in the ground. These posts will stay as long as the fence is there, and no hog can lift the fence and get under it, and it will also prevent cattle and horses from crowd- ing the fence in trying to get what is on the other side—J. R. Koontz, Bremen, Indiana. Economy in Steam Heating By running a steam-heating plant in the following way, much fuel can be saved at little expense. > Repack all the steam valves with valve-stem packing. Get a %- in. pipe plug for every radiator air valve. Repack the gauge glass, try all the cocks and see that everything is tight. Close all radiators, except one. Raise the steam, taking off the air valve on the radiator left open, and wait until the steam comes free- POPULAR MECHANICS ly. Then, with a glove on or a rag wrapped around the hand, to preyent scalding by the escaping steam, insert a \%-in. plug, with a little paint applied to the threads, and screw it tight. Do the same with the other radiators. Also, if there are any air valves on the lines, take them off and plug the holes. Be sure the air is all out of the system. Do not try the petcock underneath the gauge glass, unless the gauge shows steam. The whole house will be heated without an ounce oi steam showing on the gauge. As there is no air in the system, the radiators act as condensers and pull the steam toward them. The radiators of the plant where this experiment was made were all warm in the morning, and the boiler was shut down all night. It will be necessary to carry out the above preparations every season.—Alexander Gray, Chief Engineer, Colored Orphan Asylum, Riverdale-on- Hudson, N. Y. Locating Reversed Field Coils Occasionally the motor trouble shooter is required to locate a reversed field coil in a direct-current motor. The usual method of going about this is to employ a compass, which, if the field cannot be energized, is the only in- strument that GLASS TUBE CORK OR WAX can be used % for this pur- pose. Under some circum- stances even this method is uncertain, depend- ing largely upon the quality of the compass as well as on surround- ing magnetic “tilinae’ influences. If the field circuit can be separately en- ergized, a little device that will never sail to indicate a reversed field can be made cheaply and quickly. Cut a % or %-in. water-gauge glass to a suitable length, according to the size of the motor to be tested. Plug one end with a cork and pour in cast-iron filings until the tube ts half full. (Do not use steel filings as steel holds residual magnetism.) Then seal the other end. Tests can be made with- out removing the armature, but it is bet- ter if this can be done. Like poles repel

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POPULAR MECHANICS 701 ich other and unlike poles attract each ther. This will be clearly indicated by e filings, which follow the form of the nes of force within the tube, when it is laced across any two poles. Figs. 1 and of the drawing indicate respectively he action of the filings when placed in - lissimilar and in similar magnetic fields. Glazing Brick Walls On brickwork in boilers, a rich brown laze for the side walls and arch is very lesirable. The addition of 12 per cent of odium silicate to the ordinary mixture f fire clay and ganister for the bonding of the brick, and a final wash of sodium ilicate and fire clay for the surfaces, help to produce a uniform glaze of this kind. it gives a surface which is impervious, revents air leakage and helps to eliminate inkers from becoming attached to the walls—H. M. Toombs, Chicago, III. Fixture Facilitates Pin Stamping An unusual device to aid in stamping the part number on pins has recently been adopted by a concern manufacturing a popular article on which a large number of pins are used. The fixture is held in a bench vise when in use. The two main parts are a sheet-metal hopper and an old gear. The hopper is bent to the shape shown in the drawing and two slots are cut in it where it is turned over to form a spring or indexing finger. The gear turns on a solid shaft slightly longer than the gear width and all parts are held together by a pin passing loosely through the shaft and hopper ends, and riveted over on both sides. The spring Safety Attachment on Extension Ladder for Hanging Up Eaves Troughs Ladder Attachment Aids in Hanging Eaves Troughs The usual method of attaching eaves troughs to overhanging cornices is to place the ladder against the side of the building under the cornice. This obliges the worker to stand on the ladder with nothing to steady himself while putting up the trough. The attachment shown in the drawing eliminates the danger of over- balancing, and has proved a time and money saver. It consists of three boards assembled as indicated and pivoted on the top rung of the or- PIN -.__ ~ stop piece just fits between the gear teeth to prevent the gear from turning while the top pin is being stamped. The operation is simple: A couple of handfuls of pins are laid straight in the hopper. After each pin is stamped the gear is indexed one tooth. The pins feed them- selves on the gear and drop into a box on the other side af- ter being stamped. —Harry Moore, Montreal, Can. — SOLID our - ” ops SSS PIN -- Sit Sheet-Metal Hopper and a Gear Make Fixture That Facilitates Stamping Pins dinary extension ladder. In use, it is held at a right angle by means of a stout hook, so that the ladder clears the eaves trough, enabling the worker to stand steadily in a natural and safe posture, and to see what he is doing. @in tempering small dies, heat un- til a piece of wire solder will just melt when touched to the dies, and then quench. \ ‘ ; SPRING STOP

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702 Preventing Danger of Explosion of Hydrogen Gas in Storage Batteries Examining Storage Batteries Owing to the danger of igniting hydro- storage teries, it is good policy to keep matches, A flashlight is much handier to use for examining the gen fumes that arise from candles and cigarets away. inside of the cells and will elimi- nate the danger of blowing up the battery and injuring the eyes. Repairing Lathe Tailstock Machinists in small shops are often handicapped when the tail- stock spindle of the lathe is worn so loose that it is impossible to clamp it tightly, which gives the lathe a tendency to chatter and makes the work inaccurate. This trouble was remedied by a me- chanic in the following way: From a piece of shafting he made a new tailstock spindle just like the old one, except that the di- ameter was left large enough to fit into the rebored hole. He finished the taper and the seat for the threaded bushing before he started on the tailstock, and prepared long plugs for both ends of the new spindle, as shown in the illustration. He found a bor- POPULAR MECHANICS ing bar about 3 ft. long, fastened one end in the chuck and ran the other end on the old center, after which he adjusted the steady rest to the bar, close to the outside end. The tailstock was pulled out toward the end of the lathe, and the spindle and the cap in the end were removed. Then the steady rest was removed without dis- turbing the adjustment, the tailstock shoved up over the boring bar and the steady rest put back in its previous posi- tion. Now all that was necessary was some method of feeding the tailstock along while the boring bar revolved. A hook, closely fitted to the tailstock and the carriage, performed this duty. The tailstock clamp bolts were adjusted and the ways oiled so that the tailstock would slide with the carriage without binding. A smooth cut was made through the bore, and this part of the job was done. He could not use the tailstock for turn- ing now, but he had thought of that in advance when he prepared the plugs for the ends of the new spindle. One of these he held in the chuck, and the other was run in the steady rest having the carriage in between, and although he could not cut from one end to the other, he could turn the surface with two settings of the tool. The diameter was carefully turned to size and filed down smooth, to make a good fit, and the new spindle was lapped into the hole with valve-grinding com- pound. The lapping had smoothed out all roughness in the bored hole, and gave a slow-wearing surface on both parts. bat- BORING BAR;, “HOOK OUTSIDE DIA. LARGE ~ PLUG - ene LL a EE ———— SECTION OF NEW SPINDLE “PLUG NEW SPINDLE ‘ fC af = a Oe PLUG = 4 2, - STEADY REST Worn Lathe Tailstock, Which Gives Lathe Tendency to Chatter and Makes the Work Inaccurate, Can Be Easily Repaired

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& A Brick-Veneer Six-Room House DINING ROOM = '2°0'x22'0 11-O"x 4-0" CEILING HEIGHT ao FIRST FLOOR PLAN BED ROOM | Pango" 9-10 x15-0" 4 CEILING HEIGHT 8x 0" SECOND FLOOR PLAN Copyright, Architects’ Smal! House Service Bureau Plan No. 6H4 Small House Service Bureau of the a hg regarding home ane. addressed to this magazine will be answered by the Architects’ nited States, Inc., controlled by the American Institute of Archi- tects and indorsed by the department of commerce, United States government. and material lists for the house shown above may be obtained at a nominal cost. stamped envelope for reply. If further information is desired send five cents and stamped envelope for a 24-page booklet explaining how the small home bureau functions and showing twelve sample plans. Blueprints, specifications Inclose self-addressed, HERE are types of houses that look cold and formal on the exterior, no matter how cozy they may be within. The Dutch colonial style, however, belongs in the class of houses that seem to be the very embodiment of hominess. The design shown here has that home- like quality to a marked degree. It is built snugly, close to the ground, and a wide porch, the outside chimney for the fireplace, two sets of French doors open- ing onto the porch from the living room, all suggest hospitality. While retaining the characteristic low lines of the Dutch colonial style, the roof is pitched so as to provide three excellent bedrooms. Each has a good clothes closet, and light and air from two sides. The living room runs the full depth of the house. A wide, cased opening joins the corner dining room and the living room. Placing the stairs at the back of the house is not only an economical use of space, but gives them unusual privacy. An open rail could be substituted if de- sired. A sunroom can be built in place of the open porch if preferred. This house is planned to be built of brick facing on tile backing, siding being used on the dormers, and with slate roof. A forty-five to fifty-foot frontage will be required if the house is built as illus- trated, If the porch is omitted or built at the rear, a forty-foot frontage would be sufficient. There is a full basement with fuel room, laundry and space for vege- table and fruit storage. Home Builders’ Questions Q. Does painting shingles do as well as dipping them? Is there any advantage in dipping them all over instead of the ends only? A. Shingles that are first creosoted or otherwise wholly impregnated with preservative fluid and afterward painted have the double virtue of dura bility and of fine appearance. Q. What is the difference between a sill and a girder, a stud and a bearing post? A. A sill is a heavy timber that goes immediately above the foundation wall It serves as a connection between the superstructure and the foundation. A girder supports the joists and spans between the posts and sill, or from sill to sill. A stud is a form of column used in framing walls and parti tions. A bearing post is generally a column standing alone to support a girder or beam Q. We are financing the building of our home on a first mortgage, but we need more money than it is possible to obtain in this manner. To whom should we apply for a second mortgage? What is a fair rate of interest to pay? Do you think it safe to get money in this manner? A. You can obtain your second mort gage from home-financing concerns who make a spe cialty of this kind of a loan The rates of interest depend upon how much money you borrow, but the greatest difference lies in the amount of commission that is charged. This may range between five and twenty per cent. Shop around until you get a fair price, but do not borrow money from anybody who has not the reputation for playing square It is safe to borrow money in this way only if you are able to meet the obligation that you incur to repay. Q. When erecting a one-story brick house with no basement, must the footings be placed in the ground below the frost line? A. Footings must be run below the frost line. Otherwise the action of frost beneath them may crack the wall. In a compact soil, such as clay, it is more necessary to get well below the frost line than in loose soil, such as sand and gravel. 703

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Q. I have a one-tube set using a variocoupler. How can I make this set regenerative? have a variometer ; please show me where to put it in the circuit and oblige. A. The

AERIAL 5 EG upsroqneant , is ; VARIOM placed in the plate PRI. SEC , —_ circuit as shown 90025 in Fig. 1. MFD Zz Q. I have been 7To005 001 using a soft de- MD. } 44) MFD. tector tube for wattle some time, but =+|+)))yp + would like to 4 change it for a > GROUND . B-BAT hard tube so as to Fig. 1 save the differ- ence on the A- battery drain. Must I change the circuit to use this type of tube? A. You can use a UV-201A or C-301A tube for the detector if you wish. However, when you use this type of tube as a detector, it is best to con nect the gridleak to the positive A-battery side, as the tube works better with a positive grid return. Q. Please send me a diagram for a simple method of connecting the battery charger and set, so that I can use a double-pole, double-throw switch. A. The dia gram is given in Fig. 2. A fuse can be placed in the 110-volt a.c. line if desired. Q. Can I use two receivers on the same aerial? My friend cannot put up an aerial and I would like to let him use mine, if possible. the B-batteries very quickly. The am- plifier tubes have to be very bright before I get good results. Can you suggest a remedy? A. Use a 4% volt C-battery; this will lengthen the life of the B battery. Also have your tubes tested; they may need rejuvenating or, if defective should be replaced

Q. Please tell me how the D-coils are wound. some 3-in. bakelite tubing and would like to build some of these coils. A. The coil is shown in detail in Fig. 3. The tubing is slot- ted and the wire is wound on in a fig- ure 8 as indicated. Q. What is the cause of fading? Can it be prevented? A. The exact cause of fading has not been discovered Distant stations will fade and then come in again though the tuning dials are not touched No remedy has yet been found I have

Fig. 3

the name of the maker or the seller of an will be furnished free, by addressing [ Editor. ]

IN accordance with the editorial policy of this magazine never to accept compensation in any form for what appears in our reading pages, and also to avoid the appearance of doing so, we are obliged to omit article described. This information, however, is kept on file and ureau of Information, Popular Mechanics Magazine, Chicago.

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