Popular Mechanics 1925-05: Vol 43 Iss 5

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_/ Tested Hookups—Page 847 25 cENTS IRNERAI L min p OPULAR MECHANICS MAGAZINE WRITTEN SO YOU CAN UNDERSTAND IT FAs = 5a

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ll make YOY an EXPERT MECHANIC in 8 weeks I Will Pay Your Railroad Fare — and Give You the Lowest \ Tuition Rate Ever Offered >’, va I mean just that! In 8 weeks you can become an expert ne mechanic. I will train you so that you can become a foreman in any shop, or own a big-paying business of your own. I will equip you so that you should easily make $150 1 (is) 15 S| a to $500 a month, regardless of what you are now doing. (SsARAGE as George Smith, of West Alexandria, Ohio, was working on | a farm for $50 a month. He came to my school and ‘ol ; my course of training. Now he is making $800 a month | from his garage and sales agency. A. J. Beall, of Mor- . gantown, West Virginia, is another MecSweeny trained “~~ _<@ a\— man who has made good. Last year Mr. Beall cleared ~*~ $85,000 from his garage and Chevrolet agency.

° * oi. Geo. Smith owns an asenq Millions of Dollars Waiting and repair shop at West Aicim | ‘call 1 dail nes Uh ents fanaa When Aanins oiieien badd Sabetiahie dinnes andria, Ohio. He makes § E \ i ne chance oO xe ! oO this 1g oney , — - fi hed my specialized « rse. There are seventeen mil- @ week. r 4 lior tomobiles and thousands upon thousands of tractors in use toda \ Millions are added each year. All of these machines are going to need : \ repairs. There isa big demand for men to do this work. And the man who Send \ know »w to do this work is going to make big money, steady money. for Personal Training Get the Facts FREE I want to make one point clear. I operate three schools, at Cincin- P 1 \ When you come to my school you nati, Cleveland and Chicago. I will E BOOK: \ tor sad tate pay your railroad fare to the school \\\ a 1n- nearest your home and give you the \ 1 | wor instruc- lowest tuitionrate ever offered if you t id " “Mac” will act at once. Don't keep plugging away at a poorly paid job Don't to rye u. I'll waste your best years working for F it t train- someone else Send for my free Emannuel Rushfeldt, / , ; t ip you book which teils you how to become berta, says: ‘‘Farnir $ : t vou can go out 1 say an expert mechanic in 8 weeks. Just day and only 20 year 4 “I am a McSweeny trained man.” sign and mail the coupon and I will ( “eed , prove to your own satisfaction that ( and step intoa position that will you ean make from $150 to $500 a ( pay you trom $40 to $150 a week. month in this easy work, ( LH. Cle McSweeny, c Pres., re = c eeny McSweeny Auto- De Teale ag ee Auto and Tractor 9th and Walnut Streets, Cincinnati, Ohio 517-521 South Laflin Street, Chicago, Ill. 1815 East 24th Street, Cleveland, Ohio Dear ““Mac’’: Send me full de- tails of your Special Offer, without cost to me,

Training Shops Dept. 163 Louis Beimer at 24 wus mo! foreman over men ma Cincinnati—Chicago—Cleveland 272°" 70." “ie (Write to nearest school) McSweeny training.

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roputiar 200 E. Ontario Street, Chicago, U. S. A. echanics Magazine H. H. WINDSOR, Founder H. H. WINDSOR, Jr., Editor and Publisher London: Hachette & Cie., Paris: Hachette & Cie., Melbourne: Gordon & Gotch 16-17 King William Street, Charing Cross, W.C. 2 111 Rue Reaumur 509-513 Little Collins St. ISSUED MONTHLY SUBSCRIPTION: SINGLE COPY, 25 CENTS In United States and its possessions, also Canada, Cuba, and Mexico, per year, postpaid - $2.50 To all other countries in the Postal Union - - . : : . - - - - 3.00 All subscriptions are discontinued at expiration. Please examine the date printed on your wrapper. Entered as Second Class Matter Sept. 15, 1908, at the Post Office at Chicago, Illinois, under Act of March Ord, 1879 Entered as Second Class Matter at the Post Office Department, Canada thly by POPULAR MECHANICS CO Copyright, 1925, by Popular Mechanics Co Vol. 43 Contents for May, 1925 No. Ae Postal Service—latest airplane safer, faster 813 Electric Power—half of nation’s used in homes A jutics—air mysteries bared to aid flight 723 Energy—movements of body measured by heat units ture—disease immune plants sought 759 Eyes Ds how to avoid strain on iby blimp for air touring 712 _ ills revealed by photographs ew daughters of the sea 795 Fire Protection—fire fighting on the waters A iexterity—more men than women left-handed 800 Flags—inspiration of “Star Spangled Banner’ A s—ambulance for cats and dogs 802 Gas—5,000 new ways of using gas A war on, to help farmers 792 Gas Burners—gas water heater with fuel control valve A paving the world’s streets 808 Glands—making giants out of mice and men , my—modelers make life mask of moon 721 Glass—rival of, bounces like ball A tics—coach invents pacer for runners 729 Gold—roaches give clue to lost mine At here—air waves like ocean waves but larger 808 Golf A le double tee made of rubber carry inaugurating party through sewer sandless golf ball scrubber tunnel 764 Great Salt Lake—waters expanding f nation’s autos 768 Gulls—Great Lakes gulls cover world on winter A le Touring—house car built of airplane wood. 752 flights f ~ A viles—Design—automobiles built in queer Hats—shaped with electric sandbag | 4. pes 793 Household Devices E | ax 4 Aut biles—Equipment and Supplies—bumper serves Inventions—two hundred daily —s ggage rack 754 Irrigation—dam in India ~ De Aut es—Lighting Jacks—jack and tackle develop six ton pull aul dimmed by foot switch 824 Kansas—more forest trees in Kansas now t hl Yi under auto cause car to show up 753 Kitchen—for campers folded in box for running board Bax] A es—Safety Devices Leaning Tower of Pisa—new base for =, brake bands riveted tight ; 749 Life Saving Apparatus er link chains for auto tires ween 774 life preserver permits sitting —— A mattress used as ‘ 1" plane ambulances 1n army use Tr 817 Light—artificial sunshine in zoo for tropical birds tors find hidden mountain pass 784 Lightning—oak common lightning target ons an agent b pistol to guide airplanes 750 Loading and Unloading at West A B i Banking—deposit chutes in outer wall 813 house moved across cemetery on elevated tracks le makes $20 Ba motor driven steel, looks like submarine 754 truck dumps brick in neat pile Beds rails on top of skyscraper 713 Locomotives—100th anniversary of B eek old homes each year 749 Lost and Found Articles—on railway trains I ience to manufacture? 786 Mail Box—revolving stand for mail boxes Boats and Boating Mechanical Drawing—fountain pen for draftsmen ent royal barge of Turkey in drydock 782 Medicine—Practice—medicine taken through skin with eboat with hand levers 753 electrical apparatus thousand miles by water flivver 769 Mines and Mining—balance scale finds ore deposits by r craft floated on air balls rowed like canoe 717 pull of gravity - r China's trade in 767 Monorail—propellers to drive passenger cars on over S head system ailway bridge planked for autos serves during Mosquito—young mosquitoes starved by poisoning washout 811 their food e lifts concrete bridge span on boat 737 Motherhood—memorial to motherhood to be built at ific treads save wood bridges own capita ashfeldt, A F g—raft floated in standpipe for wrecking crew. 708 Motorcyc'es acing B Materials—decay in stone buildings 776 broad jump contest pace id” @ Cabbages—prize cabbage at show 812 fitted to fight forest fires C ig Machine—double faced pocket calculator 808 quick action stand for motorcycle Chir —sailors make queer costumes 792 witr streamline body Ch —gas given in home with mask 759 New York C:ty—how Broadway got its name Ciga electric cigar sorter 776 Parachute—falling a mile for a diploma Clea —portable motor concrete finisher 807 Patents—30,000 English patents Con —for ceiling of automobile 717 Petroleum—hay rids harbor water of oil Crir rmored motorcycle bank patrol 708 Photography C: Word Puzzles—puzzle frame with loose letters 750 color photos at one exposu.e Der y—auto equipped as dentist office 812 exposure meter for prints Dis i—armless write with pencil in belt on chest 754 Pigeons—airplane coop carries to races I s—tool for designs has many uses 738 Piuers—pocket, shaped like a wrench f ol for cutting holes in metal 823 Porcelain—imitation porcelain and marble from feld- veighing the world 739 spar —camp schoolhouse on wheels moved by Postage Stamps—60,000 in world tive 816 Postal Service—mail box on street car ect Satteries—connecting dry-cell batteries 852 Potatoes—oil from potatoes unfit for food iContinued on Page 4] Copyright in Australia Copyright in F racce 768

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[Contents—Continued ; Press—inkless, turns out complete (ypewritten letters. 811 Wolves—waron ss... goes 812 Prize Offers and Announcements 879 Woman—Occupations—woman’s work in many fields.. 719 Propellers Wood Carving—carving furniture by machinery . 803 four bladed propellers on ‘‘Leviathan”’ 760 Wood—fiuid ends blue stain losses 786 more speed on less fuel with dummy propeller 775 Woodwork—electric shaping tool fits hand ‘ : 801 Radio Wool—paper-lined sacks for shipping Sewene es .. OT how to pick your set . 777 Words—origin of seagoing Se Eee er | 822 questions and answers 880 X-Rays—for treating whooping cough............... 761 several languages spoken at once through relay system 751 Radio Aerials AMATEUR MECHANICS aerial supports of metal improve reception 785 Automobiles—Repairing circular, non-directional aerial 737 preparing car for summer driving............... 833 Radio Antennas—talking tape for indoor aerials 759 silent top buckle for Ford mck lotee wna Sedo sae eae de 837 Radio Apparatus Boats and Boating device protects tubes brecsiane 860 barrel canoe for bathers nd ae hey Ker ae se . 845 making cushioned sockets . ee 860 paddle for child’s rowboat. ; 830 rheostat permits neat mounting ; 860 Boots and Shoes—preventing uneven wear on heels 842 Radio Application Brushes—how to care for 830 letters sent through space by radio 809 Built-in Furniture—Part VI—furnishing a _ clothes radio fog signal service to be extended 793 closet 839 radio the latest crime detector 709 Cookery—paper tells baking temperature ‘ 841 Radio Broadcasting Cork—bottle cork holder ay 830 radio signals artists 738 Electric Lighting—making trouble lamp......... 842 records of announcer’s voice correct faults _ 722 Electricity—electric cord troubles .............. 846 what super-power means 775 Enamel—enameled ironware ............ 2... eee ee 842 Radio Construction Fishing how to lay out and drill panels 853 clamp for fishpole : a 846 inspect aerial and ground before summer 860 separating telescopic fishing rods ? ; 831 label your battery leads 860 Football—air valve for bladder 841 Radio Loud Speakers—tiny, three by five inches 741 Garden Tools and Appliances—electrically heated Radio Phones—small, fit in the ears 708 sprout box ‘a 836 Radio Photography—fans draw picture broadcast by Gardens artist 763 build hotbeds early eee ; 837 Radio Receivers planting back-yard garden ._........... 825 combined clock, radio and phonograph 764 Glass—plate glass scalloping tool............... 846 getting the best for your set 847 Goats—nursing kids artificially ............. ; 831 one-tube ultraaudion a favorite 60 Golf—vulcanizing golf balls rerer 830 set concealed in doll’s body 720 Infants—portable baby yard ang Socacaiae . 842 two-tube loud speaker 857 Mailbox—rack on country corner cry 831 Radio Repairing—improvising shaft extension 852 Mops—old stockings make a fos Sensi at £36 Radio Tubes Le Photography—drying prints quickly ......... 846 examine ‘‘dead’’ transmitting tubes 859 Potatoes—thawing frozen ......s—ss........... ws es 845 show wide use of radio ? 786 Poultry—teaching young chicks to roost....... one Railroad Accidents—caboose plays leapfrog in wreck 791 Printing—homemade printing press............. 843 Railroads—dining room on wheels ; £24 Sporte—water dice ....... .... sce cccccccess 837 Railroads—U. S. A.—new and abandoned in 1924 713 Tool Box—handle makes, of drawer.............. 84) Rats—rat and weasel run cable under river 752 Waterproof—cloth, how made... ......seeeeeeees 837 Road Making Machinery—burlap spreader for cement ‘ roads 737 Rust—tallow dipped steel wire binds bridge to concrete SHOP NOTES base 782 Automobiles—Repairing Safety Movement handling Ford driveshafts.................... 865 street booth holds stretcher 781 inserting valve spring pins cents aa 6 ed 869 traffic police dummy at crossing 816 Blueprints—quick way of making notations on.. 874 Sahara Desert—express offers variety of travel 785 Boring Bar Holder ‘ ‘ 865 rews—driven into metal like nails 807 Burlap—treatment for mildewed te eee, 878 Seals—herding of Alaskan increases trade in skins 741 Carpentry—spacing nails in boxes eas 862 Signs and Signboards—three signs occupy same space 760 Dredges—overcoming dredging difficulties. ... 87 Slide Rule—holder with rubber pad . 800 Garage—service cards in 869 Solder and Soldering—regulating heat of soldering Gasoline—safety basin for washing small machine parts irons 856 in gasoline ee 876 Stage Mechanism—ropes back of stage 749 Glass—stain for glass windows bra tetas 863 Stains—chart tells how to clean fabrics 816 Hayrack—substitute for binding pole , nt 871 Steamships and Steamboats—ventilators used as water Irngation—small irrigation plant ee Ree 870 intakes 791 Ladders—adjustable footing for ladder neweee 864 Stone Mountain—huge granite block cut from 768 Lathes—truing chuck backplate 870 Stones—making cast stone 743 Loading and Unloading—method of dumping trucks 864 Street Traffic Regulations—three speed sidewalks in Lubrication—lubricating high-speed shafts 863 subways 707 Metals Submarines—guns of, guarded by glass 786 joining roofing metal sheets 871 Sun—animal increase due to sun spots 722 testing machine parts for cracks 865 mommy age ag | cap with “ear pockets” 719 Molding—concrete molds for making fender tools 874 Swings—rock like boat on waves ... 774 QOil—good drying 875 Telephone—booth with lattice legs -. 811 Paint—removing paint and varnish : 869 Tobacco—tested with mirrors 785 Painting—precautions in eeha 878 Toothbrushes—where toothbrushes grow on trees 754 Polishing Wheels—storing Ae erry: 868 Toys—dolls with interchangeable heads 802 Poultry—feeding troughs for - 863 Tractor—and plow lay radio ground wire 822 Pulleys—pulley and gear speeds and sizes. . 866 Trays—folding, carried with one hand : 812 Signs and Signboards—moving signs for small s‘ores 878 Truss—adjustable auto truss and jack : os 722 Swine—wheeled hog swiller is cet ks ‘ 878 Turtles—turtle farm earns profit ............... 781 Threading—holes im thin plate............... 87! TFypewriters—balanced in desk 785 Tools—board on which to hang................ 875 Vacuum Cleaners—for army mules.......... i 729 Trailer—unusual automobile ..............---- 873 Ventilation—washing air for homes favele 765 Trese—quewesine .. 8 5 ck ccc ivcecncess 869 ocations—opportunities in building trades : $18 Ventilation—ventilating the dark room.........-.- 86) atches—manufactured by machinery ae 817 Vulcanizer Weather foot operated PEE eet Ts § and the ocean currents , , 787 rollers aid in testing tubes ie eneeearae tree rings tell conditions er rite 713 Wagons Weatherstrip—shaper run by motor atau aes 791 low wagon for silo filling oasil 8 Welding—electric “‘insect’”’ welds steel.......... ‘ 729 wood sled on wheels Bis Wheels—fiexible disk auto truck. ..............45.. 801 Welding—portable welding outfit on motorey,cje 874

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= ee 2aneauwreave a= oe on op cD oO oo of - i a -~o- oo on co CO OO Pe ee Swe P > . > : ¢ . REAP Mew Tek WObe Pade of a —_ set, a newcomer in radio WJIAR Providence WwGR Buffalo > ) > v » _ 4 WIAR Pred oe often uys inferior batteries. You WEAR Cleveland { Minneapolis know such “saving” is really wasteful. WWJ Detroit wcco i St. Paul rie . - . 1 WF! Philadelphia WSAI Cincinnati Tell your friends who are about to buy receivers that the best batteries obtainable will prove to be the most economical. ‘Tell them to buy Ever- eady Radio Batteries—they last longer and, because they are greatly su- perior, they give complete satisfaction. Vanufactured and guaranteed by NATIONAL CARBON COMPANY, Inc New York San Francisco Canadian National ( a rbon Co,., Limited, Toront Ont EVEREAD Radio Batteries ~they last longer

For y | RADIO, IGNITION GRNERAL P au £s x Eveready Columbia lgnitor Dry Cell “4” Battery for all Dry ¢ ell Tubes 1% volts A

on multi tube sets

-DwY

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Sketch of Monorail Line to Be Built in Paris, Showing How Propeller-Driven Car Will Be Suspended; Power Wiil Be Supplied from Electrified Track or from Internal-Combustion Engine in Train—See Page 751 , OG Dri. yryyram a ee ey Se PEt

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opular Mechanics Magazine WRITTEN SO YOU CAN UNDERSTAND IT MAY, 1925 No. 5 and Pa Men Making Giants Out Of Mice * 4 ‘ me R Lis ve as racco and guinea PF ero ) t \ : b S oe ire po bilitie yppe ) en the tre i é 1i1t Oo i overy b i Scie t t ¢ We ere tonishned | ( ) Il ersit ot Ca ort! i \ } € ts ) | l ¢ treated 1 nto cattie sheep 1h ey is ¢ t é t not g ¢ geese, ducl ind chickens ould re- 1 but put unde é or 1! n such an increase in e and rapidity é é ‘re it 1 d it come in rowth that one-half the live stock now tact t] the digestive t sues, at luced would furnish the same quantity administere daily, rather than at int foodstuffs as those raised today. quent intervals, we could turn n he discovery was made, after nine Ito giant since every ng ¢ irk, b\ Dr Herbert M Evans, I | Se » also announced that he had found ident one can be pretty certain tl barren animals may be made capable the etfects the animals received from t lucing young b eeding them witl treatment are due ‘ to the 7 ertain food. The first of these findings Very recently, Dr. Miriam 7 at the extract of the pituitary gland, I | e been able t that even tiny organ hidden in the base of t the us complete ¢ ot t iin, when injected into the tissues of liv- Is rea l, on nistration of t lu ¢ creatures, no matter what their age, the anima tart again to add t t rts a period of growth limited in time body Dr. Evan he does not | int and rapidity by the quantit when tt be possible to apply this tre ministered and the duration of adminis ment to | I n bein be 1 | é tion. Rats born in the same litter and periments are not yet complete, and eated daily with “pituitrin’’ extract out cause of the difficulty tain ‘ by fitty per cent other rats of the tied ext ttromt t O me litter reared unde thie Lime mynd fluid ! ¢ e ¢ ‘ s but witho tu Not ontv did I ned tr )

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706 POPULAR MECHANICS more while growi: under the pituitrin trea: ment than they do wh: not sotreated. If thee periments continue to | successful on t] larger animals and men as they have been rats—and Dr. Evans a: his associates believe t!} they will be—anot! possibility is the elimi: tion of the dwarf. second result, and pri ably the greatest of would be the relief of t undersized, und nourished child and 1 use this extract building up the hun body to make it more 1 sistant to disease as o! or aid it in recuperat after disease. The de cate nature of the pit: tary gland and its p: tion at the base of t brain put it almost ou side the pale of surgi operations. This con tion has made the obtai: ing of the extract difficu by Feeding Them Pituitrin the administration of the pituitary extract produces the same result in all age sex, there is believe that it will have the effect on large Most mat rats, fe- cardless reason to ol or every same ‘r animals, even to man. imals and birds of large size of growth, requiring two vears , SIOW are or more to attain full size. An exception is the largest bird that flies, the ¢ rnia condor, which usually equals, and often urpasses in weight and wing spread, the condor of the South American Andes Naturalists now are beginning to believe that this bird, which attains full ! in one year or less, is aided in its rapid de- elopment bi i 1 erowth 1 the substance of the pitui- ) tary gland which it obtains from the brains ot the animals on which it feeds. lurther experiments are to be tried on cattle, sheep, hogs and the agricultural domestic fowl at college of the University of Calitornia in an effort to produce larger animals in the time now required to rear the normal animal. Success would mean a largé increase in the quantity of food meats produced in this country on the same amount ot hay and grain. since tnimal ) far experimented on eat n Wr yvnowrseya Two Rats Used in Tests Designed to Show How Size Could Be Controlled vy» aa and its administration t human beings almost i: possible, until the di covery by Dr. Evans that the injection « the pituitrin from any animal into a1 other immediately starts the latter on it way to becoming a giant among its kin The second of his discoveries is a vit min carried in an oil produced from t embryo, or germ, of wheat, which he | found essential to reproduction. Rats f on certain foods, notably orange juice, | came barren, or at least non-reproducti but when given some of the wheat-embr extract, immediately reared families. diet of lettuce leaves has the same eff« on the rats. “Just how will this concern the practic problems of human weliare?” Dr. Eva asked, and replied to his own question: “It is difficult to make any statemen* r garding the practical significance of t! work, primarily because we have demo: strated that the new vitamin, which ha been named vitamin X, is abundantly di tributed in common foods. The fact th one set of organs has a dependence up: some substance which must flow i through the mouth, and cannot be fabr cated in the body, is worth all the atten tion that we can : e to it ~ eo alah « ae. Le.

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POPULAR MECHANICS 707

ancl * -_ 7 = me, a ES eas a

P-otected from Autos and Street Cars, the Pedestrian in This Subway Arrangement Enjoys an Unobstructed Sidewalk, and Three Platforms Moving at Different Speeds in the Same Direction Three-Speed Sidewalks in Subways to be tilted and emptied when cleani: Planned to Relieve Congestion the apparatus is small enough to be tached to the side of a sand box, saving the Sidewalks built in the form of separate expense and labor of setting up and 1 neg p! itiorms to carry pedestrians at taining the ordinary types our and six miles an hour have been buckets and standard \ ore ed for a subway in a southern city. is claimed for the scrubber t! ire to be built next to the stationary ability to ! p the pellets cle re and so arranged that persons may 11 one to another with little ible. Seats are provided for the fastest Phev will move in the one direction ne side of the street and in the oppo- on the other. The arrangement, en- eers believe, might eliminate the need rains in sections where only short t inces are traveled. Sandless Golf-Ball Scrubber Saves Players’ Hands \ eolf-ball washer which cleans the eres quickly without the use of sand lislodge particles ot grass and dirt, has been devised for installing on teeing r\} tands. The scrubber, which performs its ork with a few strokes of a plunger, re lieves the plavers of the need of wetting +! ~eo "7 G t; di = ] I< vater _ hand re) Pp u . oe = hy Meet. Golf-Ball Scrubber That Requires No Sand to | Its Fitted with a bracket which allows the can Work and Saves Players’ Hands

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708 POPULAR MECHANICS Armored Motorcycle Bank Patrol down, it sprung a leak and the pump pr: to Foil Bandits’ Attacks sure was increased to overcome the wa and maintain the water at proper leve Armed motorcycle bank patrols have Owing to the presence of several buildi: been established in Chicago to afford at its base, the tower could not have be: dismantled by oth: methods. Rank Has Answered the es Bandit; an Armed Messen- ger Patrol Ready for the Streets How a Chicago { Small Radio Phones Fit in the Ears Most radio fans agi that the headphone cause discomfort after they have been worn long time and wor oiten object to them bh: cause they disturb 1 hair. These, and oth: drawbacks are said have been overcome su cesstully in a set bet manufactured in Englar in, which small metal n zles that can be slippe into the ears replace t usual type of rubb: phone. Each recei weighs only half ounce. An outside pe manent magnet is fitt to afford additional su port to the phones, wl better protection tor messengers and to the coils and diaphragm, concealed 1! discourage attacks from bandits The little metal case and an outer ring, : men ride heavily armored sidecars with a _ said to allow accuracy in adjustment. 1 steel compartment between the handle- set has a resistance of 3,200 ohms. A fle bars for carrying valuable packages and a __ ible cord with the usual plugs connects t! shield to screen the passenger from bullets pieces to the radio. These featherweig in front. Both the driver and his com- phones can be worn for long periods wit! panion are armed, rifles, sawed-off shot out fatigue, according to reports, and whe: guns and revolvers being included in their equipment. A reward of $2,500 is offered any member of the squad for each bandit caught or killed. The outfits are faster than automobiles Raft Is Floated High in Standpipe to Hold Wrecking Crew In dismantling a huge standpipe, 144 feet high, in Beaumont, Tex., the tube was pumped full of water and a wooden raft was floated on the open top from which workmen operated acety lene torchestocut the structure to pieces. As each section © View of One Oates eee _— was taken out it was dropped down the in- side of the pipe. The level of the water not in use, are carried in a small leather was decreased as the cutting progressed, pouch that fits in the pocket or handbag thus keeping the workers’ platform within easy reach of their task. After about sixtv- @ Nearly 5.000 new ways of using gas have five feet of the standpipe had been torn been devised in the last ten years. masa fe eS A /. . ae a oe oe ee ee ee

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POPULAR MECHANICS 709 C a Filament IME thousands Switch on the Rear of the Front Seat Is Visible on t Controlless Radio Receiver Radio—the Latest Crime Detector Broadcasting Descriptions of Criminals Makes Every Listener a Potential Member of the Pursuing Posse i radio fans were tening one night to a concert broad from station KOP of the Detroit po department. ke off in the mid: uncers voice Was heard saving: been ] I rder has just now broadcast t} ers.” The de- of the crime, f] ished to police idquarters ephone and a de- Iption of the by layers and the car which they had i followed. ‘The rder was hardl e minutes old en every radio for a hundred or more und had the de and knew om to watch for ile Ss S ore important ll, three big tour- € cars, cruising he city loaded with Suddenly the music le of a note and the ‘A We of tl committed. e description le Rear View of Controlless Up Police Headquarters ne Detroit arry three detectives and c¢ riot guns, had picked message, for all ceiver©rs , so built that they pick up not! Police Department's iw an armat up the same radio carry five-tube re- but the police headquarter s’ broadcast At verged first ard the tow the Which Can Broadcast Only Receiver the rs had taken. an Pick warnins 1 1, 1e the pouce con aptl g, t oute esc As they sped throug! 1) Lif through the ba Iditional d ck yuncer’s voice was the loud speaker of each front seat etails. The slayer car had been seen several blocks from the scene of tl! crime, where it had turned into a ne The p hifted th accord route. cars courses ngly. As minutes passed, each suc- cessive report was radioed to the po- ce cal and all ng the route the slave! were takit lio listeners de serted their re-

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710 POPULAR 1 ceivers to hurry out and keep watch. Those who saw the slayers’ car rushed in to telephone the news to headquarters, where the messages were relayed through the air to the pursuing police cars. That is science’s latest contribution to- ward hunting down the criminal. The hue and cry after details of a crime flash through the air a volunteer posse that is ready with eyes on every road the criminals may take. The radio as a police aid is not a new thing, but broadcasting of the voice to millions of brought a new element tion. It is not so far back, as years are counted, since two continents thrilled to the first wireless crime detection, w] word was flashed from the S. S rose,” outward bound from England to Montreal, that the missing. Dr. Crippen and his companion were aboard. Some days later they landed in Canada, and not until they reached the dock w aware that their identity had become known. Dr. Crippen paid with his life for the murder of his wife. Several police departments now operate arouse receivers has into crime detec- “NT ae Jiont- are they broadcasting stations and regular]; put on the air lists of wanted persons and stolen automobiles. Hundreds of cars have been recovered, accerdi: g to Detroit officials, through the daily broadcast of de- ee } } t ] SCTiIp ) and numbers otf stolen ve Frank F. Campbell, at Left, Wealthy Larchmont, N. Y., MECHANICS One of the most amusing radio poli cases is described by W. J. Burns, form: head of the bureau of investigation of t! department of justice. A youth purchas: a radio receiver, presenting a false ord from a public high school. When 1 dealer found he had been defrauded, | called in a detective agency. That nig a local broadcasting station read a me sage which described the boy accurate! even down to a small scar on his chee detailed the charge against him, a: offered a $50 reward for his arrest. expected, the boy and some of his frien were listening in. The next day mother appeared and paid for the Radio is also proving of value in ident fying amnesia victims and locating mi: ing persons. Not long ago a girl who h been in Cook County hospital at Chica; for more than two months, suffering fro loss of memory, was taken to a broadca ing station and made a brief speech, a ing anyone who might recognize her voi to identify her. A relative in St. Lou happened to be listening in, hurried Chicago and identified the girl. Relatives of missing people and poli departments are turning to the radio help find them. Hardly a night pa without one or more of the big broadeca ing stations sending out an aerial SOS someone who is wanted at home. d & Underwood Copyright, Underw Business Man, Presented This Transmitting Set to Town Police Department to Increase Efficiency mse.wneweftktwT —_— - 7 a ciwaerewwFewFresaeea£rwTirena et

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Pp, Broadcasting ice Bulletins from Burlap-Hung tudio at Detroit ice Headquarters he Shotgun Squads trolling the City in lio- Equipped Riot the Police Radio gineer, Shown adc isting, Per- ted Controlless Re ver Which Picks Nothing But Po- e Station KOP;: Re ng Sets Are Being ed in All Police tomobiles in Phila- phia, and Lower- Picture Shows stant Police Di- POPULAR MECHANICS x Les L&T Left, Power Panel of Station WLAW, of New York Police De- partment; and Below, Transmitting Equip ment of Detroit Polic se) Headquarters, Station KOP, Showing One of Giant Tubes behind Screen Back of Meters

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~ pend (~~ POPULAR MECHANICS BABY “BLIMP” IS FITTED UP FOR AIR TOURING Fishing from the Cabin of a Baby “Blimp,”’ an Air- craft as Easily Handled as an Auto \meric first sky coupe,a pony “blimp” designed for air touring, is now being marketed. his tiny dirigible is 100 feet long, thirtv feet in diameter, and has a gas capacity of 47,000 cubic feet. The ship, capable of a speed of fifty miles an hour, is driven by a sixty-horsepower motor and can maintain flight for twenty hours with- out refueling. It is as easily handled as an automobile. Service over both land and water can be rendered by the machine, and as it can be let down either on ground or water, it is said to be well adapted to the making of motion pictures, hunting, mapping, and as an aid to fishing fleets. The car has room for two passengers. Above it is a vent, about the size of a stovepipe, for controlling the pressure of the gas in the envelope above. The three- cylinder air-cooled engine is in the front of the car. Only one-fiftieth as large as the famed dirigible “Los Angeles,” it has been predicted that the pony blimp may prompt Courte q Zeppe the erection of public mooring n where drivers may tie them up, much motorboats and launches are now docke Long-distance overland cruises in flee are also possible with the air yachts, a1 as they are light and easily handled, the are well fitted for air regattas and raci contests similar to those held for wat« crait. Great Lakes Gulls Cover World on Winter Flights That gulls and terns inhabiting the Great Lakes region scatter over a range during their migratory flights ha been indicated by a check-up kept on banded birds, according to William | Lyon of the Inland Bird association, wh: marks more than 3,500 of the fowl vearl) in an effort to learn their length of life mating habits, and traveling ability. Even those reared in the same neighborhoods wide 14 POPULAR MBCHANICS

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POPULAR MECHANICS 713 the northern climes have been found follow different routes on their winter ghts. A pair of terns, released after ipture and banding in northern Lake lichigan, were trapped in Colombia, and nother specimen taken along the Niger er in Africa, bore a marker which had en attached to it on the coast of Maine. thers identified by bands were found to ve traveled from the Great Lakes to ints in Georgia, Florida and Texas 3ed on Rails on Top of Skyscraper Gives Air and Comfort \ bed that runs on rails can be moved m its room to an outside sleeping rch for the night when a control but which turns on motive power ane uses folding doors to open, is pressed I 6 } “ the morning it can be returned to the . : Be Bier mn al a Pek - . , Pages of Weather History, Cross Sections of Trees de by a similar operation, affording the Whose Rings Reveal Climate Conditions eeper the comfort of the warm room for , i essing during cold or rainy weather. Tree Rings Tell Weather Conditions e control switch is so located that the and Which Way Wind Blows upant can set the apparatus in motion hout leaving the bed. . The device is Scientists of the Field Museur talled in the private apartment of a ural history expect to learn esh-air enthusiast at the top of one of ™ eather has been like . =U Y ork’s downtown skvscrapers more in the vicinity ot cago he rings on oak and willo been found that trees ot kinds register thin their trunk ecord ¢ f thie S¢ nd that gre 1 the ( Trew 1 he ( ed nm tiie 1 1 9 com] ons, deduction t of 1 l l id 1 ees Tet Ve ( be a8] e study turthe he ¢ ¢ ed to ¢ ( Ose the wood ed I \ id é st ul ( e ¢ di p - “( to ¢ ‘ ‘ re , 1 ‘) t o*T ¢ té t ¢ e¢ ( the de ‘ te + P = % ni i t ¢ e¢ In ‘ 1 earTt t] e T | 5s clo bark on the é } e\ ] ne W | ) ¢ From Novy. 1, 1923, ti let date in 1924, 1.318 1 railroad were authorized 1°79 . : 459 ¢ apat mer the interstate commerce = — : a Phe wear hefarce ¢1 Bed on Rails Which Moves from Its Skyscraper Room to Open- A . lt ae adit Air Porch When Control Button Is Pushed qcitions were reversed. _— a. eee ee = aon 45 @ee 4 Go ee es A

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14 POPULAR MECHANICS ots . rie ace air A =, a penn + om ¥ eo » pal . i " pe POS Regi ete — Ba ot A nor PROT seth OO OPEV tl 8. ft KI Oe a Artist’s Conception of Dramatic Leap of Two Airp!ane Pilots When Their Ships Collided Recently at Kelly Field, Tex., Showing Parachutes Just Opening to the Wind 716 POPTITLAR WERCHAWNICS

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POPULAR MECHANICS 715

l-Off from the Wing of a Martin Bomber, Photographed Just as the Pilot Pars chute Jerked the Big One Free from the Jumpers Pack Falling a Mile for a Diploma }< YR unequaled simplicity in graduation cockpit of a DeHaviland plane Ihe exercises, the U. S. Army parachute craft goes up a mile, and at a signal fro ol at Chanute field, Rantoul, Ill, prob- the pilot, the student climbs over the side 1 takes the world's prize. To win the of the fuselage, takes a deep breath, lets eted diploma at the end of a six weeks’ go of the ship, gives a lusty kick with his

tensive course, the student is required feet and falls backward into space. After lo but two things—and neither of them sufficient time has passed to insure that he iting an essa is clear of the air- peaking a piece. f{ 1 plane's tail, he pull stead he folds | J -s the rip cord, the parachute and parachute, if prop- es his stand o1 erly folded, opens

and some two min- utes later the eround rises up and e wing of a giant | lartin bomber he plane climbs e in the air, and, 1 the student ignal from the | iin. Parachute tructor, the fis not d: udent pulls the gerous, at le t cord of hi anvone' connected ute and is yanked with the school into space tell ‘ so i | some of them have jumped so mat times they have me two minute ter the groun es up and bumps m—and the first lost count of the f of his gradu- total. There is no Oss of consciou ness at anv time on exercises are er. The second

consists of re- during a jump, even ding the par } on he t t1 ] ute and taking a ; a The se ition roe ae Standing on an Airship Wing Ready to G p for a it in the after Pull-Off; Exhibition Jumpers Wear Two Chutes jumper gree

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716 POPULAR MECHANICS that of settling back into an incredibly deep and soit teather bed. No feeling ot falling accompanies the drop, and when the parachute snaps open there is no jerk. Instead the harness tightens and the jumper, who is usually falling in a hori- zontal position or head down, is righted. A slow oscillation, like that of a giant clock pendulum, follows. The distance from the waist belt on the jumper to the top of the parachute, when open, is thirty-two feet, so the man swings easily at the end of his supporting ropes. As the chute toward the ground the jumper has time to enjoy the view and call to those The only exciting part of the jump is the last 150 feet or so. Higher up the view is so broad that the jumper feels he is settles below. 1 barely downward, though his rate drifting of descent is Coming Down, Above, and the Landing, at Right, Showing Ground Crew Helping Spill the Wind trom Parachute n 1Q DMDIYT Aap approximately sixteen feet per second But when he gets within 150 to 209 feet oj the ground, the earth appears to leap rig! up to meet him. His descent actually | grown no faster—the illusion is entire mental. There is barely time to remember to draw up the feet and bend the knees for an easy landing when the thing ts over The actual force of the fall—regardless of the height from which the jump was made—is about equal to jumping off a rail road flat car, or at least that is true on a calm day. If the wind is blowing, driit- ing the parachute before it, the force of the fall is equal to jumping from a flat car on a train moving at a speed equal to the wind velocity. In other words, a jump on a day when there is a twenty-mile bree is equivalent to jumping from a flat c going twenty miles an hour. The real thrillers among parachute jumps are those made in emergencie where the flyer was forced to abandon crippled plane. The elect who have done that belong to aviation’s most exclusive organization—the Caterpillar club. One of the most thrilling of all occurred in March of this year when two planes collid- ed at an altitude of 5,000 feet ovef Kell! field, Tex., and both pilots leaped and land VeiuFabe? RB °*@ fal!

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POPULAR MECHANICS 717 d safely. The planes were part of a quadron of nine ships engaged in battle ractice, chasing an observation plane. hey were tumbling and circling around a whirling maze—what the flyer calls a og fight—when two of e ships crashed to- eether with such force e wreckage remained ked. Cadet Charles \. Lindberg, piloting ne, slipped off his safe- belt and leaped. eut. C. D. McAllis in the other shi lowed suit. Bot! led their rip cords ter dropping several indred teet and the opened. e wrecked ships shot t them as they fell d landed in a flaming iss. Strange to savy, few scratches were the only injuries received by the flyers. lhe army parachute costs $620, meas- ires twenty-four feet across when open, nd is attached to the wearer by twenty- e stout silk ropes, twelve of the shrouds ing down to one shoulder, where they re sewn in the harness, and thirteen to he other. The thirteenth is red, while all e others are white, the red one being ed as a dividing mark in folding the irachute, and also to “spill” the wind out it after a landing. rachutes The harness is made of heavy linen pe, two inches wide, equipped with eavy iron rings, snap fasteners and uckles. The harness has a belt about the ist, supporting bands around each leg, rossed bands over the shoulders and wn to the waist belt front and rear, and finally the double tapes on either side to hich the shroud lines are attached. Everything depends upon the way in hich the chute is folded, and extreme ire is taken to have it just right. The arachute is stretched out on a fifty-foot table, with the pack and harness at one nd, and the little pilot chute hanging over he other, where it is held down by taking i turn around a peg. The pilot chute, vo feet across, is built with ribs like an 1mbrella, but with a spring arrangement hich causes it to fly open unless held inder pressure. It is attached to the top f the big parachute, and is the last thing packed and the first out. When the rij ‘ord is pulled and the pack opened, the ittle chute flies out, catches the wind and pulls the big parachute aiter it, ) wmmiwnwe’yry av

Air-Ball Water Craft for Use in Aquatic Paddles or Water Craft Floated on Air Balls Is Rowed Like A bottomless craft designed for water sport and held afloat by large inflated balls, Canoe Sports Which Can Be R: Propelled by the Wind wed with is propelled by a large paddle similar to that used for a canoe. Owing to its light construction and buoyancy, little effort is needed to keep it in motion, and as it car not retain water there is no danger of its being swamped in heavy seas. The-appa ratus may be employed by swimmers for exercising or can be used bv beginners an aid in learning. When traveling wit the wind, the headboard acts as a sail an also as a fender against splashing of wave For purposes of storage or transportatior the balls may be quickly coll ] tached from th 1 apsed and de- e frame. Compass for Ceiling of Automobile Can Be Illuminated at Night A compass designed for attachment T

t! e ceilit ry OF CIO ed type automobi es be pla in line with the driver's eee t 1 Tré e}le ¢ | oht use cé l \ ¢ 1 ed T 1 I } i = i thy he cy ] 7 com that it @ ‘ luable lin deciphering rec ti10ns i l oute < armromwmrmysaéftTrhCUT seta

Y1T0

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718 POPULAR MECHANICS Glimpse Women at Work in Many _ Lands to Be Seen at the Chicago Fair, April 18 to 25, and Here Are a Few in Their Natural Surroundings, a Woman Farmer, Two Japanese Maidens Remov- ing Raw Silk from Co- Java Woman a Pattern on Dyeing, and avajo Indian 3lanket Weaver ~9() POPULAR MECHANICS

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POPULAR MECHANICS Woman's Work in Many Fields Shown in World’s Fair \Vhat women have achieved as invent- builders, managers and in many ther fields since the beginning of the entieth century will be shown at the oman’s World's fair in Chicago, the first nternational exposition of its kind ever eld. Its purpose is twofold: to review ttainments in the new activities in which omen have taken part in recent years, and ) give information concerning various vo- tions and help in obtaining employment, desired. The idea of the exposition was riginated by Miss Helen M. Bennett, inager of the Chicago collegiate bureau occupations, and was directed by a oard composed of prominent Chicago omen. Booths in a large exhibit hall ill be devoted to products gathered from any lands to women’s skill with achines and hand implements. One will » given exclusively to women inventors, me of whom will be present to demon- rate their creations. Attendants in col- ortul native costumes will display the reign wares. Nurses and welfare work- ers will illustrate the services they have rendered on battlefields and in cities; omen athletes, architects, mechanics and experimenters in radio will share in the review. Several foreign nations are ex- pected to participate through their con- ulates and many women prominent in te and national politics will be guests. show Bathing Cap with “Ear Pockets” Has no Buckles or Seams ‘Ear pockets” are provided on a bathing p as a means of protecting them against e entrance of dirt particles and the ressure of ater. The head- piece fits the wearer snugly and has no buckles or seams to interfere with comfort. Once in place, the gear is claimed to be proof against loss. A similar guard is also de- signed for wear underneath the ordinary cap, pre- venting the outer covering from slipping off in the water, and keeping the hair in place and free from moisture. 719 Exposure Meter for Photo Prints Saves Waste of Paper For both the amateur and professional photographer, a meter which determines Print from Exposure Meter, Showing Different Degrees of Development and Time-Gauge Figures automatically the right exposure for prints on bromide or gaslight papers, is said to avoid wasting of material and assure bet ter results than can be attained by guess ork. It is simply a small piece of film, bearing photographic images of twelve dit tints of successively deeper tones > it, the meter is placed between the negative to be printed and the paper hen the exposure is developed, it how a series of light and dark shades from which the one most satisfactory ma be chosen for the rest of the prints. On 1 the margins opposite the different grad tions, are fractions for the guidance oi t] photographer. For instance, the test | taken forty-eight seconds and the best re sult correspo!l ds to the shade produce | next to the one-twelith mark. Dividing t] time by the divisor of this fraction give four, the correct exposure in succeeding prints, 11 that degree of deve ’ opment is desired. This tester gives equal lv good results for thin, fogged and almo opaque films or plates, and can also be used in enlarging where further saving i effected as only a small piece of paper needed. On this work, the meter is pinned to the easel, in tront ot the paper

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720 POPULAR MECHANICS Radio Set Concealed in Doll’s Body Makes Toy Lifelike Concealed in the body of a large lifelike doll, a three-tube radio receiving set ‘ right, ( Ur vood Radio Doll Which Conceals Three-Tube Receiver and Can Be Carried About While Operating equipped with a loud speaker can be car- ried about while in operation. The toy may be placed in a sitting position on a chair or table making an attractive orna- ment as well as providing entertainment. Dials for tuning in the set can be easily reached for adjustment and in case of needed repairs or inspection, the head of the doll may be removed to uncover the loud-speaker mechanism. Protection has licate parts of the machine so it can be operated out- doors in any kind of weather. pl \ ided tor the more de New Base for Tower of Pisa to Stop Further Leaning Pisa’s leaning tower 1s now so far out of plumb that engineers fear for its safety and the Italian government has appointed a commission to take steps to anchor the structure from further slanting In this wonder in marble, Galileo, the great as- tronomer, is said to have solved the riddle of the pendulum, the secrets of the speed ot falling bodies and invented the ~99 WMWMNVYMWTT «ay telescope. Some of his theories, it is said he never could have proved but for the way the tower leaned. It is now reported to be more than sixteen feet out of ver tical, having added nearly a foot to its in clination in the last 100 years. It is fift three feet in diameter at the base and 180 feet high and rests on foundations onl ten feet deep and no greater in circumfer- ence than the tower itself. The tower harmonizes with the architecture of the great cathedral near by and was built rival the famous campanile of Venice. In the eighth story is a set of bells. Quick-Action Stand for Motorcycle Operated by Rider’s Foot To hold a motorcycle firmly erect when the machine is at rest, a quick-action fold ing stand has been patented for attaching to the footboard frame. As the vehicl comes to a stop the brace can be pushed down by a slight movement of the rider foot so the machine can be supported « the stand and its wheels. When t! cycle is started again, the holder may be snapped back against the frame with a touch of the driver’s heel. Used b policemen, messengers, and other motor cycle riders called upon to stop frequent! the device saves time occupied by setti: the vehicle in position and eliminates t! need of lifting or pushing the heavy m chine onto the ordinary stands to | them upright. In parking, the cycle m be easily moved about on its wheels wit out raising the footboard brace which ¢ not be damaged in “spills” or cause a dents, should the rider neglect to fo up when starting off Quick-Action Moto-cycle Stand for Manipulation by Rider's Foot; Insert, Folded Up against Frame uarTwegetyryatTrnc | ero ow™ & Te

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POPULAR MECHANICS 721 JODELERS MAKE LIFE MASK OF MOON FOR MUSEUM ow the as placed on yon looks exhibition. Iti en seen painted in light rough a blue and yellow, erful tele- pe is shown t large mod in the Field seum of tural his- It por- ivVsS 20.000 and floodlights 4 . 11 ] are installed to vive ita more natural appear nce and to e1 | isize the shad of the peaks | depression and he model made in Ital itures so that a few mo- Two Detail Views of Craters and Mountains at Model's Edge and nts, a visi- Entire Face, [llustrating Relative Size to Human Figure shipped to tl r can see country in sec mut all that scientists have been able to tions and assembled Charts and lettered n of the shape and location of forma- photographs of the moon have been placed s on the satellite’s surface after cen- near it for the guidance of boxe ies of study. Peaks of the mountain res, the jagged edges of what are be- eved to have been the mouths of vol- Broadcasting Power Is Inexpensive noes and the barren, pock-marked etches, the “seas,” are all accurately At a recent forty-five-minute prog epresented on a plaster coating over a broadcast by WHA, the Univer itv ¢ . - m ‘ ee . ees, eee Sees i inal id spherical framework of steel beams Wisconsin, it was cal ulated that the co | wood, nineteen and two-tenths feet was only three cents. This figure repre diameter. Three vears of research and sented only the actual cost of the ele odeling from actual photographs were tricity consumed, no other items such as required to complete it. Noted astrono- the depreciation of the apparatus being ers carefully checked all details before it taken into consideration

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~2 ra) ra) Adjustable Auto Truss and Jack Saves Time and Labor Replacing the wooden horse and block- ing ordinarily used to support automobiles Hoisting Auto with Steel Truss Used as Jack While Inserting Another to Support Load undergoing repairs, an adjustable steel truss has been constructed which serves as a jack. The device is suitable for any car and may be set for any de- sired height. The head is designed to fit the axles without interfering with any opera- tions on the running gear and leaves ample clearance for the removal of the parts. With the addition of a wooden lever, one truss can be employed as a jack to raise the car, while others are used to bring the load to the also necessary level. Animal Increase Held Due to Sun Regularly Changing Its Spots Many million miles separate the spots on the sun from a rabbit, but scientists declare that there is a connection be- tween them and that the _ periodic changes in the number of dark masses on the sun’s surtace partly ex plain certain facts the growth of and animals. Records of the spots have been kept for 150 vears and it has found that they increase to a maxt- mum about every eleven vears. This high point is accompanied by a low-temperature period on the earth, it is said, while fluctuations in at- mospheric pressures, rainfall, tracks of concerning plants been storms in North Amer- ica and the rate of KOA NMWSrA YMOr’yYyTawyp POPULAR MECHANICS growth of the redwood trees are all cd clared to correspond to the changes in t} sun-spot numbers. Records kept by tl Hudson’s Bay company since 1845 said to show that the number of rabb skins received reaches a high mark at time when the sun spots are at a min mum. The sunlight is believed to have direct influence on one of the vitamins the food the animals eat and thus affe their numbers. Due to a climate fluctu tion of unknown cause, every three a: one-half years, a small arctic anima known as the lemming, attains vast nui bers and hordes of them migrate to tl lowlands, and even into the sea, dying the thousands as they plunge into it. Records of Radio Announcer’s Voice Aid Speaker to Correct Faults To help radio announcers to correct a1 faults of speech which might affect clea ness while broadcasting, an instrume1 records and reproduces their voices heard “on the air.” Since by the -machi: speakers are enabled to hear themselve they can detect any defects of which the may not be conscious. It is expected t employ the device in a course of trainit for radio announcers as well as to assist perfecting a system of standards to be f lowed by those doing vocal broadcasti Records of announcements from variou stations are intended to be made with instrument during a period of two weel and can be run off in about an a hour Recording Apparatus Which Reproduces Voices of Radio Announcers for the Purpose of Correction and Training of Broadcasting Speakers ATQROrTTYraAnwarrT eo

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POPULAR MECHANICS 723 Playing with Air Shows New Laws to Aid Aviation Simple Experiments You Can Do at Home [ ) SCOVERIES which he hopes may are to draw a partial vacuum above the volutionize the art of flying are wing by the downward stroke and to fan ed by ©. H. Keefer, an inventor the air backward, creating a partial vacuum is devoted nearly thirty years to ahead of the bird, and piling up an ¢ wind currents. creased air pressure behind it [] rting with the theory that the pro- creased pressure, he says, exerts a for er type utilized for both ships and ward push under the tips of its feathers, nes is scientifically wrong and in- and thus drives the bird through ent, and that if pace. The trouble properly un- th present a 1 + od the secret e flight of a t rid acc’ g or a flv he too » Keetet \ t build an ropell use ? » designed like a e ot glen I's body, to fly e il e region thout wings ‘ . , nd er is working t t h i radically novel ‘ t res} er, on which ¢ P it nts are pe nd it devel ig His theory is Also the bird’s ere al ‘ ; only partially uum oO tain it in flight, eir blade 1 differing from r ¢ let lanes of an air- ‘ e! ture ol! except when er to overcome bird is gliding. é ¢ In addi her times, he to the faults of ves, the duties Simple Experiment, Showing Force Exerted by Air ne ap hts er, tne he bird’s wings Stream Clinging to a Curved Surface \ g desig owing

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724 POPULAR MECHANICS Blowing against Metal Disk, at Left, Makes It Cling to Tube and Revolve; Blast on Front Disk, in Center Causes Rear Disk to Move toward Blower; Right, an Unusual Propeller to head resistance, uses up considerable power in pulling the wings through the air, while the thin trailing edge of the back of the Ving lets the wind currents slip off without returning any power. Therefore he l t! ed to develop a type of propeller employing the air forced backward to push the ship forward, which would utilize the trailing vacuum behind its blades, and therefore need less power, and which would pack the air forced back- ward on the surface of the ship, so that there would always be excess pressure be- hind it to push forward into the vacuum created ahead of the propeller. By a simple experiment he demonstrates that an air current, when driven at increased ve- locity over a curving surface, follows around the curve. Take an ordinary water glass, a candle and a small tube. Light the candle and place it on one side of the glass, then hold one end of the tube against the glass from one-half to two- thirds the way around from the candle, and blow through it, the angle of the tube being such that the air current will be forced against the glass. Instead of being deflected from the glass, the air cur- rent will follow right around its curve and blow out the candle. Blow ona level with the flame to extinguish the candle: other- wise the flame will bend toward the air "9G POPT'TT apn stream and cause the air to appear to be detlected from the glass. The reason { its peculiar behavior is due to the fa that the atmosphere has a normal pre sure (at sea level) ot about fifteen poun per square inch, while there is no cort sponding pressure in the space the gl occupies. Therefore the air current pressed tight against the surface of t! glass by the atmospheric pressure, travels around the line of least resistan Chis peculiarity of air in following curved surface is utilized in many of Kee ers experiments. One of the simplest made with an ordinary sheet of pape Hold it so that it remains flat and blo across the surface. No movement r: sults. But let the paper hang down, hold ing it by the corners nearest the face, and then blow. The air current follows dow: the curve, decreasing the pressure tivere and the ordinary air pressure below the sheet will lift it up. Next, Keefer puts a fold in the pape: two or three inches from the end farthe from his face, and then, by drawing the folded part down over the edge of the table, gives it a curve. When he blow across the paper the air current travel across the flat surface and up and arout the curve, with the result that the curved flap is forced up and toward the blower by AT RCTYT AAT OOS

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POPULAR MECHANICS ~? ~~ CS Left, Flame Drawn into Air Current Deflected Upward by Box; Right, Air Following around Glass Draws All Candle Flames toward It. Both Ex- periments Show How Aijir Rushes to Low-Pressure Area in Wake of High-Velocity Stream d Left, Air Curre Clinging to Sur- face of Waste Basket. Will Extinguish Candle, or Several Candles Can Be Blown Out by Sending Air arour Successive Curved Surfaces in Experiment with Glasses, Above: the Flame Is Drawn Forward in Test at Right, but Take Glass Away, and Effect Disappears

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Nor 426 the air pressure underneath. It flaps back toward the blower in seeming violation of all the popularly accepted ideas about air and its forces. From there, his experiments progress to a sheet of paper with folds and similar curves in both ends. When he blows down the flat surface between them both flaps are flipped over and toward the center of the sheet, where the blown cur- rent at higher velocity has decreased the pressure. His paper experiments form an endless and fascinating series. Take a strip of paper, three inches or so wide and ten or twelve inches long. Fold it about three inches from each end and draw the part between the folds over the table edge to give it a curve. Place it on the table and hold the nearest end down with one finger, while blowing a current of air the flat surface. The air goes up around the curve and in its ef- fort to continue that movement, being pressed in by the atmosphere, it com- presses the curved section and draws the farther flat surface toward the blower, producing a complete reversal of the di- rection of movement. Next place a lighted candle just beyond the farther end, and hold that end down across POPULAR MECHANICS also with one finger. Blow through th: tube and the air current follows over th: curved hump, but, since the loose end ; held down and cannot move, the current continues on and snuffs out the cand Then relight the candle, let the farthe: end of the paper remain free, blow, an the paper will again move toward you while the candle remains lighted. The lighted candle can be used in man ways to demonstrate the peculiarities o air currents. Place it on a book or sma box, two or three inches high, and bac! three or four inches from the edge near est you. Then, with a small tube, |! against the base of the box or book. air current is deflected straight upwar along the side of the obstruction, and o1 up into the air, drawing the surroundi: atmosphere toward it, and the candl flame toward you. Another interesting experiment bh which Keefer demonstrates the influenc: of high-velocity air currents when de flected is made with a piece of wire and two metal disks of the same size. Thx wire is bent in the form of a rectangl: with both ends twisted together to form handle. One disk, strung on the wire soldered firmly to the end nearest | TI the nel Partially Closed by Disk; High-Velocity Stream Blown Cone Draws Other Air into Its Wake, and Exerts Backward Pressure on the Cone SS ES ee oe ee eS Sr a Soe ee Left, Ball Jumps Upward Out of the Hand When Air Is Blown through Fun- Right, through HO nonynowe’yy ay ATW CO*(VTYFaA rt’ Tera

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~o* twe MECHANICS POPULAR Showing Tiow Bird Piles Op excess Press PENT il wo Push et Orward, “ara “Siri Li a ; n Airplane Wastes This Force ¥ irrent around the g! —— Jines Demonstrating How a ¢ ( e otiy t a sma piece tube, | ina curre etal tubing stuck Tt rough the ce 1 the candle flam«e ¢ draw1 keep it sliding easily, 1s strung « dl it Next place three or four glass« e upper horizontal wire of the rectangle row, touching or toucl r and ding it in front of him and blowing ehted candle e curve betwee nst the fixed d k, he causes the se ) ( Yiasse nd bev vd the ( iovable disk to sli ] thest one Blow the ( ent on thr e air blown against the fi is ce t l it l f t cted outward, its increased velocity be eac!l n g out the ¢ ( iccompanied by decreased pressure, Still more interesting demonstrat 1 all the surrounding air rushes in to are made with a sma cellu 4 the void The rush of air carries the pong ball, about an incl nda |] 1 ible disk along the wire toward the diameter Hold the ball above the e1 er. Stick four candles up in a sem of the rubber tube and blow on it and 1 rcle, and pl ice a glass inside the curve can drive the ball up into the att ere ey form, so that it stands two or three it will bounce about on the sible candle Chen, with the column as long as vour breat

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Next hold the ball against the wall, and blow against it, through the tube, and the ball will stick to the wall, moving about as you move the tube. The first of these is an old experiment, but he has another which is of his own invention. Soldered to the end of a small copper tube he has attached a little copper funnel, the sides of which form a ninety-degree angle. In- side the end of the funnel is a cup-shaped copper disk, fastened to the funnel by three soldered wires. When he blows through the tube the air is deflected by the disk and passes out the sides of the funnel, the air currents on opposite sides being at ninety-degree angles with each other. As soon as the ping-pong ball is held three or four inches below the funnel the situation changes, however. There is no air pressure in the space occupied by the ball, so the atmospheric pressure drives the air current from the funnel in toward the ball’s surface, and once there the currents follow around its curves and the ball jumps out of his hand and clings to the funnel above. \nother demonstration, which has pos- sibilities as an interesting parlor game, can be made with a glass, the ping-pong ball and the tube. Place the glass on one side An Amusing Parlor Game of “Jumping Ball” in Which the Light Ping-Pong Ball Is Drawn into Directed Air Stream and Literally Jumps from Table into Glass 730 POPU LAR 128 POPULAR MECHANICS of the table and the ball two or three fe away. Hold the tube so its end will dire: an air current forward on the side of th: ball nearest you, at aslight angle justabo the center. Blow, and the ball will rise a graceful arc and fly over toward t glass. A few experiments to get the ang| and determine how much wind you nee and it is possible to drop the jumping b into the glass. The jumping shot is fami iar to billiard players and golfers, but t! the same thing can be done with no mor: material aid than a current of air may b: new to most of them. As the result of his years of experime: tation Keefer evolved a simple propelle: consisting of four tin blades stuck into cork, which was free to revolve on a p The little blades were bent in a semi-cu shape. If one were to hold the cor propeller in front of himself to blo against the blades, to all appearances th« cup shape would catch the air and cau the cork to revolve to the right, or clo« wise. But blow against it and just the reverse happens, for the cork turns in t opposite direction to the clock. In othe words, when air is blown against it, it volves in the same direction that it wou if propelled by a motor behind it the Skillfully MECHANICS

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POPULAR MECHANICS 72y ; Runners Awaiting the Starting Signal from a Mechanical Pacemaker Which Assists Athletes to Judge Their Speed and Keep Up with Records and Schedules for Training Coach Invents Pacer for Runners Vacuum Cleaners for Army Mules So They Can Judge Speed Save “‘Skinners’’ Time and Work train track athletes to judge their “Mule skinners” in Uncle Sam’s army ng speed, a mechanical pacemaker in are relieved of considerable disagreeable t the University of Wisconsin sounds work by using electric vacuum cleaners | at regular intervals to mark the time for their charges instead of the familiar ed for racers to cover various dis- currycomb and brush. The outfits have With its assistance an athlete a dust bag, hose and nozzle speciall ged in practice sprinting can tell shaped for the task and are carried by a her he is traveling behind or ahead of strap about the attendant’s waist. Dirt ule. The pacer, which can be and loose hairs can be removed quick] l as easily as a suitcase, may be and it is said the mules seem to enj ted to sound time signals at deter- the treatment fully as much as an ol | periods up to 100 seconds in length, fashioned scraping The cleaner is iv be used for either short dashes or erated from the camp lighting circuit istance running. The machine, on the inventor has worked for about vears, was built in university shops. Electric “Insect” Welds Steel or welding piping, | plates of ships and other articles, an ric “sewing machine” n as an “insect” be- e it resembles a fly ppearance, is report- to have a capacity of ‘feet an hour. It is | to knit the pieces to- her by means of te-hot steel wire | from a bobbin and sed under a powerful to help form the weld. — “Policing Up” an Army Mule with Vacuum-Cleaner Outfit That Is Replaci the Currycomb and Brush _— mrmemaiwmyserTrwyT a We agcwoeeaogwprnyrfiafé.sef'é'rT ree nod

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POPULAR MECHANICS Fire Fighting on the Waters Boats That Have Feet and Powerful Pumps Guard ECAP ASL of o twenty e7 Rivers and Harbors in Our Cities throwing as much water eleven boats, Chicago four gines. independent of city with navigable streams have j ll 1 ] mall | re it anv second to peed \ fireboat look ike an overgro 1 , to the scene « contlagration, a modern On its lo steel-floored decl fireb t one tiie t ¢ ent nit tern are two sta pipe Cal Cc e i , . : F ‘ en | t é ly é iwainst a brass nozzle, the boat ter 4) , , ‘ Ni and belé S tue ¢ n = . . “st med ) r ) ] é ere t e ( r ¢ i e ‘ 1 +) + . ere ope Vv ¢ e O 1) Oo lKé tne € e | .. = e e Cc! tected b treet b feet Phese e poll fr up int ertiy] 1 ( t ¢ é the barre ) u T¢ treat 1 reo tiie ¢ I pen F be nN k1 is p S } 10.000 iiions nut ( ire } 1 ec id ] ered b 1 eparat 00 to 300 pou ene o n the nc} Vhe e boat t fire, t | 1 , size ot the no ¢ eet are let 1 ) { 1 to ’ , . : . | ile oats ¢ S€ t sand vards the crait 1 1 ¢ ting th the ct nes F : . 1 ’ Be ot hose to assist street companies. should or pressing against the bank the fire be three or four blocks fro the cutting off the tet uDD ’ : ’ 1 ca, re \ good fireboat costs a quarter of takes \ tvpical electrically ad 11 yn do lat but some ot t] em | ive bh vat. uc] s thre ““(;raeme Stewart more than pa ) e r es 1 } ¢ ( cago ; 122 feet fr or JOY - ’ 7 in 1 prevented it one é Ne Yor} is welg ind t oO otors ot 20 ee oD cdl. ~ ar ] Sa ew. Pp. he Re ee

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+ RE aE Ee > oe. x POPULAR MECHANICS 731 LPO BE TE NT ee ee eee eS apkee | Diagram of Boat at Fire, Showing Feet Lowered into Bottom and One of the Water Intakes; Inset, Spud Elevated above Deck and Fireman at Winch That Operates It rori.vnyryTy a we arnoenoeyrroafttae‘'tT}yT eee moe

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MECHANICS AAR POPU

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POPULAR MECHANICS r each, directly connected to ropeller shafts. Power for motors and for the pumps, an individual capacity of gallons per minute, is fur- | by two turbine generators ied with steam from two rs of the marine type, in a pressure of 140 pounds \intained night and day and pounds when fighting fires. units are arranged in pairs, n each side of the ship, and them are condensers, vac- pumps and an exciter for the es, which also supplies elec- eht for the boat. The boat wn as a one-man control that is, it can be manipu- entirely from the pilothouse 1m the engine room, saving ecessity of repeated signal- \ switchboard control fur- a cut-out preventing inter- ce from either. e other units of the depart- a fireboat must answer all e calls within its district. At ters, a bunk room and living a stone’s throw from the where the crew of twenty, for night and ten for day e, eat, sleep and amuse them- when not on duty, is the . assembly of fire-alarm in- X} ents. These are connected e central alarm station from h calls are relayed from the boxes. There are the tele- nes, the telegraph “joker,” used to sig- e different companies, and the ticker, -inclosed mechanism that records umber of each fire-alarm box “pulled,” tattooing dots on a narrow strip of as it jerks out of a little opening a bell rings. The number of the repeated four times, by the bell and lots. Ona wall is a chart showing the numbers and street location of each the district, a list of the department’s calls and other station numbers; and drawer below, a card-index system le entire city, giving the location of box and the numbers of the engine panies that respond to the first and essive calls. hat happens when a box is pulled in district patrolled by a fireboat? The tant the glass is broken or the hook led down, an electric circuit is com- ted, registering the alarm and its loca- at the central office whence it is re- ed to the fireboat’s quarters. Perhaps ants ~ v MA, WITT Aww | At Night, Searchlights Point the Way t re through Crowded Steamer Traffic and x vy Aid Firemen in Dark Buildings it is box 314. “Ding, ding, ding,” then slight pause; “ding,’ another pause “ding, ding, ding, ding,” followed by longer pause, and then the same tl over again three times, clatters the bell while the tape comes inching out of the case, bearing its tattoo that tells the nur ber of the box. Before the number is re peated, the man on watch, one of the crew always on duty near the instruments, has caught it and so have the rest. The peaceful room snaps into action. Down come feet from the stove and radio head phones are torn from ears. “It’s a go,” sings out the captain who has been making out his report, and every man is headed for the stairs as a big bra gong explodes with a furious din in the bunk room, the signal that rouses the crew at night. Perhaps the pilot and the eng! neer are the only men on board the boat The pilot has heard the clatter and is on the alert. “Three-fourteen,”’ shouts the captain as he reaches the gangplank. The ATEOCTAnrree War

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POPULAI > \ ME ( HANICS ent C1 | Ke t r | r I i 4 \ ( 1 é tii ( 1 e r t+ ¢ yyotr at t a pT i f Fireboat Brigade on the Reach Tall Buildings w! Ot é ( | ( t ¢ é ¢ ¢ { t t T 1 T ¢ Aer \ ) t 1 et e( T ¢ ¢ ) t + t’ { T t T { | T t t t é + ¢ et ¢ $ ¢ ¢ t ( ¢ 1 t | { t t ~ ean) \ I n Treat € ) t ¢ thea a ¢ ¢ r ¢ ¢ ¢ 4 ( { enews s.A® » off s I Ou ive et »} + a Cl t ter ¢ t the duct our f the fire ren ‘ the ree fire fight ned 1 Wo; Ore Ct eC eT t Tt Tr? ‘ Cndae4»nrs 1 pre te? Tt é ne + " } + + é ( tor ’ te 1 t+ + ] ] cte | t ] + + + ore tiie Li¢€ up eng t ‘ e hoat \ 7 i¢ ( T t Cc t ( t t t | t t COT ¢ t ’ so] s¢ + ¢ ¢ ( e thie e not ¢ + 4 € al I t i re i the boat start rict +} > , , if cy I scene r ( URC Battersea Park mper h IWAN TCS a Dock Fr to rf Tle i rl ' 1? i e ar ee

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POPULAR MECHANICS 735 i Reading a Box-Alarm Num- ber from Ticker Tape at En- gine-Company Quarters Testing Dispatcher’s Board Cables at Central Fire-Alarm Office LZ 4 A Boarding Fireboat for a Run and Getting Hose Lines from Forward Storeroom; Pilot Is on the Bridge Ordering the Hawsers Cast Off; Steam Is Up, and by the Time the Crew Has Reached the Deck, the Boat Will Be under Way >? POPULAR MECHANICS

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136 POPULAR Orne the intake valve by raising a lever | water rushes through the 450 square nches of opening, a set ies of three-eighths inch holes cut through the steel side of the boat At the fire, the captain scrambles ashore nd reports personally to the chief in command “Company i chief,” he outs above the chugging of tleeter en- at the spot. like a serious fire. “Lead aw i} four lines,” may be the chiet’s reply. That means business for the fireboat. If not wanted, “stand by” or “go home” the orders } eines already Perhaps it looks 2 would have been Hlose is connected and pulled to the place where it is wanted by a cart lat regularly ac companies the fireboat for this particular 3 probably the from the chief Phat means Pipemen, already at their post turn the big valve wheels and streams that have throbbing at the shut-off plates leap along and _ stiffen the lines, quickening the nozzles into hissing mouths that pour their broadside into the from a street company tl purpose. “Play away,” is next order ater been flames Phe standpipes are used when the flames are within close range Down in the boiler rooms, the stokers are heaving coal, engineer and pumps and turbines, pipemen aided by men from the street companies are either on deck or on shore handling the lines under the direction of their own captain and the chief, and the pilot has assumed temporary command of the deck, directing the men at the gates or ordering the spuds lowered if the boat oiler are watching possibly MECHANICS ins to drift. The hazard of fall ls follows the fireboat too and the p is the man responsible for his craft such an emergency. Back irom the fire, the company ne fies the central office that the fire is out and the task of cleaning up the boat, pu ting the hose lines away and getting re for the next call is in order. Like men other companies, the crew of the fireb plays aw iiting game, but there is a dai round of tasks that must be done, such polishing the brass, emptying the boat ashes, work in which all hands join; a1 then, of quarters must be ke shipshape and scrupulously clean. Rivers and harbors of our cities ar little worlds of their own, and here the fir: boats find all sorts of jobs to do, man of them reports of the course, escaping vessels’ logs. y When f ermen get marooned in the ice, the fire boat is often called to attack drifts t thick for other craft and rescue the Scows and other boats frequently call help when they need pumping out, at flooded bridge foundations have to be drained. At the end of a year, a fireboat may ha answered only 200 calls, traveled less tl 500 miles and actually pumped water le than 100 hours, but no one measures tl] notice in the regu] sometime value of a fire company on a time ba and property owners and fire chiefs unit in declaring that when a big blaze breal out on the water front, one of the most welcome sounds is the screech of a demo fireboat coming to the rescue Fast Motors Have Almost Displaced the Horse for Fire Service, but in Some Cities, Gallant Steeds Still Thunder Eagerly Forward at the Call of Duty i033 POPULAR MECHANICS

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POPULAR MECHANICS ~? 2 2 TIDE LIFTS CONCRETE BRIDGE SPAN ON BOAT

Position under Span, e Bridge Section Removed, n the Boat and Swung Permit the Dredge to Pass Through en the California av commission : concrete bridge »ss Alamitos bay, Long Beach, the | et span, forty six and t feet ucted so that it easily to permit a ough when work was on the city’s recreation park. The eht of the engineers was rewarded when a call came for the dredge long, was be removed rer tO pass thr e span was swung aside and placed vith only a few hours’ delay to traf- nd at a cost of only $500. A barge was ler the loose section at low tide and e water rose in the channel, it boosted e concrete block above its Supports on bridge until it rested wholly on the of the The current then ng the craft and its load aside, leaving passage clear for the dredge. A tug ed the barge back to the bridge as as the tide began to recede, and three after the span had been raised, the ion settled into its original position. barge. Burlap Spreader for Cement Roads Prevents Damage to Surface For covering new concrete roads during e curing and drying period, a reel on heels that follows the form marks and unwinds a wide “blanket” of burlap or ther material, has been introduced. It is ‘onstructed of lattice-steel framework, onsists of only seven parts, which can be knocked down for convenience in ship- ng, and is operated by means of sprocket- nd-chain drive with a crank. In order it no seratches may be caused in the +

POPULAR ME <¢

finished surtace by the covering, it 1s laid not dragged, over the road Circular Aerial Is Non-Directional and Works Inside or Outdoors \ new type of antenna, which, ov to its circular shape, is claimed to be 1 directional and to result in equally good re ception from all points of the compass, has appeared in England. It is designed for either in- door or out- door use. It consists of two rings sup- ported on an upright by means of two crossarms. Special braid- ed copper- wire tape is wound from one ring to the other in such a manner that pract the entire surface is to the coming radio waves. It is claimed this type of aerial will increase the range of many receivers.

exposed HANICS 739

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i039 POPULAR MECHANICS during the later months. Radio devel ments were the most numerous subject the patents, more than 800 being grant: an increase of 200 over the vear bef Many applications from inventors in t held were not pressed, the originator parently realizing that their ideas were many cases commercially useless or become out of date while the matte pending because of the rapid progre this science. Many patents were household improvements and the invs tions were made by women Drawing Tool for Fancy Designs Has Eleven Different Uses Outlines for a wide variety of

< ATi ~ - terns can be quickly and accurately Radio Microphone Equipped with Signaling Device to vith a simple dra ng mstrument Notify I rmers When to Begin Broadcasting combines eleven tools in one t ; ° ° , heet of aluminum cut t 1 ¢ Radio Microphone Signals Artists ORES Hd “RES SER PR SG, to Get Ready to Broadcast tab, perforated to hold a thumbtacl Thirty Thousand English Patents ents in Great Britain totaled more than 30,000

i t vear, according to re- } , ports, aa ougn tne ; ] | ] number 1s 1,UUU0 less t n V rece ec n 192 3 F ee Instrument in Use and Samples of Drawings Quickly Made with It; Thun there wa a Increase ; tack in Center Is the Pivot

740 POPULAR MECHANICS

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POPULAR MECHANICS i iodd

hye t t rt 1 ‘ ) i 1 | He 0 It | 1 , ¢ t é ¢ e e p ¢ é } t ) ‘ ¢ ¢ ¢ } ‘ } t <« , j ¢ ( ¢ é I] ‘ t — ¢ ¢ y e ~ t t ' r t N t r ee e ) j ! »\ the e € ( 1 e , ne t 5.000. D t S -| ‘ iceu t t ete } ,iny) lLe ¢ t ) I I ¢ Lulul ¢ ec i , POPULAR MECHANICS 741

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740 Taking Pictures of Patient’s Eyes with Optical Cam- era; Above, Finished Photos of Eyeball Eye Ills Revealed by Photographs Taken with Optical Camera 1 Diseases of the human eve can be de- tected in pictures made which photographs the inside of the or with a camera gan. Ills that might require extended examinations to locate by ordinary meth- ods, are said to be quickly disclosed by the lenses which faith- POPULAR MECHANICS mated that there are 1,095,841 incandesc: lamps along this sparkling street, and 1 more than 2,000 men are kept busy cl ing and repairing the displays. From t first moving sign, depicting a chariot the clusters of illumination have gro until they now include kittens that balls of twine, women with walking in electrical ] umbre] rain, clowns juggle and scores of other displays. Kitchen for Campers Folded in Box for Auto Running Board Everything necessary for the prepa: tion of a cooked meal is provided campers and tourists by a portable kitc] which can be carried on the runni | board or trunk rack of an automobile. 1] apparatus includes a stove and oven i baking and a refrigerator for the preser\ tion of perishable The cabin which contains the utensils need not dismounted from the car when requiré but removable legs are furnished for u it the outfit is to be set up for a long riod. It is of metal throughout and p against fire, weather and dust. As kitchen occupies little space when pac! it is suitable for installation on a yacht a tent or as an accessory for light hou keeping. Compartments are arranged { dishes and cutlery, and the cooler is we insulated from contact with the stove foods. fully reproduce the in- ner surface of the eye ball. With the aid of the pictures, diseases and their effects may be eas ily studied and remedied. To illuminate the interior of the eve while the plate is being exposed, a pow- erful electric - light tube with reflector is attached to the instrument. Got How Broadway Its Name The brilliant gleam of thousands of electric signs that nightly tell their stories to passers-by is the answer to the query as to how Broad- way, New York, has be- come known the world over as “The Great White Way.” It is esti- Everything Needed for a a ““Home-Cooked"’ Meal Is Provided by This Portable Campers’ Kitchen Carried on the Auto Running Board 7424 POPULAR MECHANICS

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POPULAR MECHANICS 741 LIFE PRESERVER PERMITS SITTING IN WATER [fo the ordinary inflated type of circular preserver, rubber trousers, slippers Paddling While Sitting Comfortably in the Water; Rig the Entire Suit, Trousers with Fins and Big Inflated Tire Belt l Pp iddles for the legs and a pair of oars e been added to relieve discomfort and ve the wearer better opportunity to h safety. The outfit is so large and e trousers so adjusted that a sitting pos- » can be assumed. Careful Herding of Alaskan Seals Increases Trade in Skins number about ise of 50,000 over last year cording to the reports of the commis- ner ot Nearly 16,000 skins ere taken in one year from St. Paul and St. George islands in the Bering sea where nety per cent of all the fur seals in the irld are said to gather during the breed- ng season. Natives there, supervised by fiiteen trained white employes, protect the eal herds, take the skins and also care for the blue foxes that inhabit the islands. While the seals are disporting themselves in the surf, vessels of the coast-guard service are stationed near by to watch ver them, and the ships follow them when they get ready to migrate. Strict provi- sions are made to keep the seals from dy- \laskan seal herds now W000, an incre fisheries. POPULAR MECHANICS ing out Not less that 5.000 three-vear- old males must be reserved ea These, set aside for breedi i” purpose are sometimes branded by sheariu y pat of fur from their head Loud Speaker, Three by Five Inches, Gives Volume and Clear Tone On Se @O f smallest loud speakers on the market is a com- bination box-and horn affair, three inches wide and five inches high, “> which is said to be j 1 - capable ot giving . considerable v ol- ume and pure tones. The horn ts mant factured of a highly polished material that resembles tortoise shell >

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742 POPULAR MECHANICS enough for the brick to pass through t!] rear, which is left open, without bindi: the sides of the body. The truck can moved slowly away, leaving the brick in neat pile. Furthermore, since the body so connected to the derrick that it n be detached from it with little troubl. one may be left at the vard for load while the other is hauled away. The fill body is pulled onto the truck by sim reversing the derrick, which is controll: by the driver from his seat and operat: by the truck motor. Motorcycle Broad-Jump Contest Adds Thrill to Police Games Broad jumping with motorcycles prove one of the most exciting events at a police men’s annual racing meet in a souther city, the contest affording spectators u Truck Dumps Brick in Neat Pile usual demonstrations in riding skill Savi Ti ad Breakage the sturdiness of the machines. Roar avimg sume s , 8 down a Straightaway,the motorcycles . _ - mT ee P a ee ‘ + : Auto trucks with a demountable type of cuided into an inclined take-off board As Truck Body Is Tipped Up and Moved Away, Bricks Remain in Neat Pile body that dumps 500 brick in an orderly slight upgrade being sufficient to s stack instead of in a loose heap have been them hurtling through the air for placed on the market for use on construc- leaps. The winner's mark of thirty tion jobs and in brick vards. In unload feet climaxed the event. The test of ing, the body is rolled to the back rider's skill came at the end of t of the truck, tipped by a two- jump, keeping his machine f1 skidding or falling in the soft masted derrick and lowered i eing most difhcult. rently to the ground, leaving space ‘ ight, t lerwood & Underw Roaring Up to the Take-Off, the Motorcycles Leaped Like Trained Athletes. Skimming over a Low Hurdle and Landing Thirty Feet and More Away While Crowds Cheered 744 POPULAR MECHANICS

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2 POPULAR MECHANICS 743 New Building Material Outrivals Original Material in Beauty of Coloring While Cost Is Considerably Less *RINDING up huge blocks of beautiful A white marble into fine gravel, run- ng the material through a _ concrete xer and casting building stone as hard as the original block yet more beautiful in coloring, and at the same time cheaper, is \merica’s most modern contribution to he building art. Starting out as a con- crete process, the cast-stone business finishes its material like any stone-cutting plant. In fact, one of the large cast- stone plants in New York em- ploys more skilled marble cut- ters to do the delicate hand tooling than any single nat- ural-stone quarry in the coun- try. The finished product can- not be told from natural stone, except for its more delicate gradations of color and their vider range. The variations 1 color are possible through le introduction of various inds of marble and mineral pigments in the concrete mix- ture. The process, however, bears no relation to any of the concrete-block systems here- Model” ‘Dae otore in wuse—in tact, it 1S orative Bit more elaborate and requires im Clay or lar more equipment than the i! +} I 1 IN Sculptors Plaster as Patterns for the Molds finest marble quarry and cutting plant The quarried marble must be ground into the fine aggregate, mixed by special equip- ment, cast in specially prepared mold either of sand, plaster or glue, the mo being made either from wooden patterns or from clay models prepared by artists and then the casting, after curing for a POPULAR MECHANICS 745

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744 POPULAR long time, is carved, planed, machined and cut like any piece of natural stone. Despite the intricate process used, the cast marble is only twenty per cent more expensive than soft building limestone, and about as much cheaper than either granite or natural marble. In natural-marble quarrying, it is not unusual to split out a 4,000-pound block to produce an 850-pound finished piece of building stone. The two-ton block is rough-finished at the quarry to about 1,500 pounds, wasting 2,500 pounds of fine marble, and is then shipped for final cut- ting and tooling on the job, paying freight aS MECHANICS on the excess 650 pounds, which eventu- ally will be cut off and wasted. The cast stone plant not only saves the freight, but actually operates on the waste of the marble quarry. Making cast stone starts in the pattern and mold rooms, where the architect's drawings are reduced either to woode patterns or to clay and plaster mold With the patterns completed, the archi tect selects the desired color, texture and surface treatment from samples prepare: from exact mixing formulas. It is pe sible to get any combination of color, m: terial and treatment desired. With natura Gy, 4 “he g A iY 7 Giant Carborundum Planers Put the Finishing Touches on the Cast Blocks, and, at Left and Right, Two Figures Cast in Marble for a Public Building 746 POPULAR MECHANICS (eee,

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POPULAR MECHANICS Delicate Tracery of Column Capitals and Other Highly Carved Pieces Are Reproduced from the Sculptor's Clay Models in Plaster of Paris and Glue, Making Due Allowance for Shrinkage in Casting and Likewise Allowing Enough Extra Material for the Final Hand Carving; the Casting System, However, Reduces Hand Work to the Minimum and Turns Out the Most Ornate Carving in a Fraction of the Time Required under the Old System, Besides Saving a Vast Amount of Material POPULAR MECHANICS

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POPULAR MECHANICS rock looks finished be- necessarily machined and cut with a soft-rock treatment, while a hard rock like- wise shows its hardness by its finish soft sott hen stone a cause it is and more delicate and sharply de- fined lines. With cast stone the architect, if he wishes, can have a marble building of granite finish with soft- rock carving. of the opportunities of- fered bv the casting procedure, several inno- Because vations new to stone- worl are introduced. If the architect icate and eracetul lintel, and yet wants it to carry a heavy load, steel reinforcing rods are introduced. If an- bolts are desired to more firmly hold the finished piece in place, they too are placed in the mold. The heavy steel loops, called set- ting hooks, are care- fully added. They are so placed with relation to the center of gravity of the finished piece that, when the crane picks them up and swings the stone up the desires a del chor ar.) ae aD Casting Floor with Mold Beds, | and a Carborundum P.aner for Grooved Suriaces | Ait-Driven Chisels Are Used for | Much of the Final Carving and | Rough Finishing Giant Saws with Carborundum Teeth Slice Long Castings into Building Stone POPULAR MECHANICS side of the building. will hang right side u and face out, just as it i tobe placed. Thesettin: hooks make it possible to erect the cast ston: much more rapidly than natural material With the molds read and the marble fro: the quarry ground and screened into various size aggregates rangi! from one-fourth to one half inch, the materi: is carefully weighed in to the big two-ton mi» ers. Even the water used is measured so that every batch receives e» actly the same amount The aggregate is mixe to produce the color de sired, with gray at white marbles from the Gouverneur, N. \ quarry; buff traverti: from Colorado: marble from green serpentine, black copper slag, and any ot a number of colored granites. If more color is necessary, manganese oxide, buff iron oxide red iron oxide or ultra marine or Prussian blue + white Georgia may be used. The se cret of the cast stones hardness lies in the

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POPULAR MECHANICS 747 pour easily. When it is finally poured contraction has al ready reached the limit and the material sets prompt], The water used to maintain the plastic character for twenty-five minutes is con siderably in excess of that used in ordinary concrete practice, but the sand mold promptly draws the surplus out of the cement, and then retains it in itself, so that the damp sand retards and regu lates the curing process. As the sand draws the water irom the mixture a suction is | ‘then set up which produces a sort t ab >. of toughness, or caseharden | { | Ne: ‘ ing of the suriace of the cast- | ' } 4S Euowore 1 YOmGs g the Portico of the Beautiful Cayuga Courthouse at Auburn, New York, Right, Pouring Cast Stone into Sand from the Traveling Mixer Which Keeps Contents Agitated ng. Instead of the one to five nutes which ordinary concrete ts in the mixer, the marble ma- erial is mixed for fifteen minutes, d then drawn off into the dis- buting ladle, on a _ traveling ne. Inside the distributor is er mixer, with churnlike lle wheels, which keeps the terial agitated for another ten utes. Cement mix- have a definite eriod of expansion 1! contraction, and long period of mix ng is designed to carry e material over this eriod, while keeping plastic enough to POPULAR MECHANICS a2 vo)

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748 POPULAR ing The weight of the stone when cured usually exceeds 150 pounds per cubic foot and its strength will range from 7,000 to 10,000 pounds per square inch, as compared to around 1,000 pounds per square inch for ordinary structural con- crete The hardened surtace gives the cast material ability not only to resist ab- sorption of water but likewise other ma- terials. A New York building was erected of cast stone after the architect had emp- tied a bottle of ink on a sample submitted, and then, after the ink dried, scraped it with a penknife, leaving the tensile all away stone unstained. After the castings have hardened for several days in the sand molds they are lifted out by a crane and removed to a curing room, where even temperature and humidity are maintained the year around. Here the bl present a rough appearance, with considerable sand clinging to the surfaces. All patterns are made slightly oversize, however, to allow for the final cutting and finishing. When curing has progressed far enough the castings go to the planers, if they are flat. Broad carborundum, re- volving at high speed, down the sur- : ; ocks and columns wheels of plane Wii Inset Hooks Make It Easy to Handle This Huge Column Section, While Chiseled Holes eceive Hook Heads of Next Piece MECHANICS The carborundum is surfaced with diamond tools to fit templates made fror the architect’s drawings, if special finishes or curved lines are desired. Huge circular saws, with teeth of carborundum, cut the blocks and bits of exterior trim to the right lengths, going through a section of stone as easily as the grocer passes a knife through a piece of cheese. Specially designed machines take care of the planing of odd surfaces, such as fluted and tapered columns. Column mak ing is in itself a special art. The Greek found long ago that a graceful, tapere and fluted column, had to have a slight bulge in the center to look straight to th: eye, while a column with straight side wouldlook concave. Each section ofa cast stone column is made from a special wood pattern, which, by intricate calculation has just the right amount of taper and bulging curve to give the proper effect when all the parts are finished and as sembled. The final finish, if it is to be one of the roughened variations, is done either with hand-manipulated pneumatic chisels or with special hammers and tools. Most of the delicate carving on lacy grills for tall Gothic windows, and similar orna mental pieces, is blocked out with pneu matic chisels and then finished by sculptor artists with hand chisel and mallet. Th: final step is the shipping. The stone packed in wood shavings, a layer of ten inches to a foot surround ing each piece, according to size laces. 130 POPULAR MECHANICS

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POPULAR MECHANICS ~2 Jo) Birds Seek Old Home Year after Year Numerous migratory rds return to the same aces every summer and re often found living in eir old nests, accord- s to Prof. Frank Smith the University of Illi- is, who stated that ousands of the song- ters have been captured nd banded for future entification. Although iny species travel hun- reds and thousands of es in their annual mi- rations, recaptured birds earing the leg markers ow that large numbers peatedly find their way ck to the homes of evious years. The entist said it has been rned that some even ke up with the same ates. Identification nds taken from dead rds picked up at points away from where ey were tagged indi- ted the great distances ey cover in annual ights and the paths they llow. Among the best- nown varieties making regular returns to summer homes are the ouse wrens. Most records concerning ater fowl were gathered from dead birds. EEE Auto Brake Bands Riveted Tight to Insure Long Life Designed to | iminate imper- ect brake - band ning, a new foot- ower machine in- ures an absolute- tight rivet, vithout which the entire band is a ailure. The ac- tion of the ma- hine, with its toggle arrange- ment, is light at ‘J the start, increas- ng gradually as the foot pressure is ap- plied. The smallest bands can be riveted either from the top or bottom side. Mute Actors That Serve Both Play and Players Well, the Jungle of Stage Ropes for Lifting Drops and Curtains Miles of Rope Back of Stage Serve as Hidden Actors Back of the glow of the footlights where few of the audience ever see them, are thousands of feet of ropes used to shift the scenes of stage productions. Big theaters often have several miles of this material, hung in what appears to the layman to be a hopeless confusion of dangling ends and loops, but every piece is exactly adjusted and performs its work silently and swiftly. Steel cable has been found unsuited to thi task because of its stiffness. The favorite size is one-inch hemp rope. It is strong enough to support the weights and cur- tains and sufficiently supple to work with- out becoming tangled @ Popular Mechanics Magazine does not publish the name of maker or seller of any device described in its pages, but this information is kept on file and will be fur- nished free by addressing our Bureau of Information. POPULAR MECHANICS 751

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POPULAR Signal Man on Observer’s Tower Firing Light Warn- ing to Passing Airship from Special Pistol Pistol That Shoots Bullets of Light Directs Airplane Express Reaching high London, is an air-traffic control tower from which wireless operators can com- municate with airplane express “trains” flying between England and the continent, and guide them to the airdrome which he can see from his lofty perch in spite of fogs and mists. At night and on dark days, signals are sometimes given with a pistol | brilliant light that at considerable distances. above buildings near bombs visible Standing on one of the balconies of the tower, the con- troller fires the lights for the assurance or warning of the pilots. shoots Hats Shaped with Electric Sandbag That Replaces Blocker’s Iron The old-time hatter’s block and iron by which headgear was shaped, has been re- placed by an electrically heated sandbag that does the work in a fraction of the time consumed by the hand process. Placed over a mold, the felt crown is made to contorm evenly to the block by the weight of the hot sand as the heavy bag is permitted to settle over the material. Previous to this operation, the fabric is subjected to a series of processes con- trolled by electricity, in which the felt is assembled from mixtures of fur, silk and nKO MECHANICS wool by and suction machines. The cut pieces are ironed at high temper- atures and partly shaped before the block- ing treatment is applied. The smoot! finish of the felt hats and high polish of the silk varieties are then produced by electric clippers and buffing wheels. 1 blowers Puzzle Frame with Loose Letters Relieves Cross-Word Worries For both making and solving word puzzles, a slotted frame with letters, that can be inserted or taken out like type, has been placed on the market It has twenty-five square spaces in vert cal and horizontal giving ample room for devising a wide variety of pat terns. Black spaces are represented by dark-colored cubes. The letters protrt above the edges of the compartments so that they can be grasped easily and kept in a divided tray that accompanie the outfit. Original designs can be mad with this board 6r printed copies followed easily, The set saves the bother of fre quent erasures and is also helpful to c! dren in solving simpler puzzles, giving them the sport of playing with blocks a well as working cross words. Divisi in the board are located quickly by fo rows of numbers, on the sides and throug! the center. cross- loose ines, ——~“—v eee ew af 41ir°«@e@ ae Ft «elale @i2FO~ 2 4/88 2° (8@6Ss -se Si ole - a : Cag Oh (m ee Tray with Letters and Black Squares Inserted, and Compartment Holder for the Blocks V52 POPULAR MECHANICS

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POPULAR MECHANICS 751

English Is Being Spoken over Dotted Line and Spanish over the Dark One, the Earphone Users Receiving the

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Wora. irom Translators in Room Back of Speaker Several Languages Spoken at Once through Radio Relay System With the help of an ingenious radio lay system, delegates at an international utomobile meeting, although they spoke different languages, were able to enjoy he same speeches and transact their busi- ness with little trouble. This was accom- plished by means of sets of earphones dis- tributed to the seats and connected to microphones at which were seated inter- preters who translated the speeches into the different languages as they were given nan adjoining room. Sounds passed to hem through openings in the wall and nto horns with dictaphone extensions. \mplifying apparatus assured sufficient volume to the different ear sets. The suc- cess of the plan was heralded as further ndication ot the possibilities of radio for romoting international good will.

Propellers to Drive Passenger Cars on Overhead Monorail System \ propeller-driven, overhead monorail transportation system is being planned in Paris to help solve the traffic problem [he cars will be supported from a single rail. If experiments on the first line, vhich is to be built without curves to save expense, prove successful, a speed of fifty miles an hour will be attempted. Power vill be furnished either by electricity taken from the rail or by an internal-combustion engine within the car. The towers for the track will be 100 feet high and 500 feet apart, giving a clearance of fifty-five feet for the carriages above the ground. If the tests are satisfactory, it is proposed to erect eight of these lines from near the center of the citv to serve the suburbs. Traffic Treads Save Wood Bridges and Protect Vehicle Tires Steel treads, laid along the wheel lines on floors of wooden bridges, guard the timbers from wear and tear of traffic and it is said, reduce vibration which tends to weaken the structures. The strips als:

Steel Treads on Fioor of Wooden Bridge Which Pro- tect Both Timbers and Vehicle Tires POPULAR MECHANICS 753

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52 POPULAR MECHANICS stop the working up of nails and spikes, eliminating a danger to the tires of ve- hicles and the feet of horses and other ani- mals. Either old or new bridges can be equipped with the treads, which are claimed to make frequent replacement of planks unnecessary and to prevent “chat- ter’ caused by loosening of the beams. Grooves worn in the wood by heavy, metal-tired trucks and which might col- lect injurious pools of water are avoided, thus prolonging the life of the timbers. On bridges that can carry two-way traffic, one strip is placed in the center and one along either side. House-Car Built of Airplane Wood Has Comforts of Home With a kitchen compartment, roomy sleeping quarters and fitted with wicker Kitchen of the Touring Car with Shelves and Cabinets Built about the Steering Wheel, and Exterior View Showing Entire Bungalow and Its Owners Enjoying a Rest between Runs furniture, an auto bungalow _ provided most of the com- forts of home during a motor trip to Flor- ida The outside was constructed of light - weight ply- wood, such as is used in btfilding airplane A linoleum floor, cabinet with ample stor age space, work shelves and a portable o stove were included in the kitchen spa which occupied the front part of the ca Broad windows furnished light and ver tilation and were so arranged that the could be closed tightly in bad weather. Rat and Weasel Help Engineers Run Cable under River Engineers running a cables from the Canadian falls to Buffalo, were halted temporaril when they found that the steel tower used to carry the wires over the streat already were loaded to capacity. While searching along the shore, workmen found a four-inch gas main extending to tl American side of the river, which is near! half a mile wide and se enty-five feet deep at t] point. Was line oT pow er side of Niagat i A large sewer captured, a string tied about its bod and it was starte through the pipe. Ha way across, it and refused to go fart! —another delay and other problem. Fina one of the engineers cor ceived the idea of sendi1 a weasel in pursuit of tl rat. The scheme worke Not many seconds late the rat popped out on t! American side, the string in tow and the weas: close behind. Heavit cord was pulled into t conduit and then th« power cable Ss w ere dragged through. stout stoppe 754 POPULAR MECHANICS A —— ee § ee — pe. > —— ~~ Role =, —-, Co a

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POPULAR MECHANICS 753 Manned by a Crew Unskilled in Seamanship, This Oarless Lifeboat Which Gets Its Power from a Lever- Operated Propeller, Can Make Speed in Oars Are Replaced by Hand Levers in Driving Lifeboat ind-power lifeboat with a series of rs that turn a propeller, thus eliminat- the need for skilled seamen in its ition, has been built in England. The can be put under way instantly and e the ordinary types of such boats can erse almost any kind of rough seas. e absence of oars which may be lost or maged by heavy waves, eliminates the . ol crippling the boat’s power in emer- neies. In use, it is believed the craft reduce the dangers of the sea, since pwreck victims, unskilled in rowing or ndling of engines, may work their way safety in the lever-propelled boat. Lights under Car Give Clear View of Auto in All Directions \s a prevention against confusion often iused by glaring lights of automobiles in ght trafhe, a system of floodlights di- ted on the ground beneath een devised with the use of magnifying isses. The soft glow makes the vehicle a Caf has POPULAR MECHANICS Imost Any Seas stand out in clear view from all direction At the red, those on the other side are green, and the front and downward beams are white. The device which is the source of the light can burn electric current, acetylene or other fuel. The various glows are caused by a series of colored lenses which may he rear and on one side the rays are . ——- Floodlights underneath Auto Which Cause Car to Show Up Distinctly at Night arranged to meet any rules of traflic cov- ering signal lighting. 2 cr cr

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(54 POPULAR MECHANICS Armless Write with Pencil on Belt | Motor-Driven Steel Canal Barge Strapped about the Chest Looks Like Submarine Writing and painting are made possible Steel barges that have the appearai for armless persons by a beltlike device of submarines coming to the surface now plying between New York and luth, covering from ten to twelve miles hour with the aid of their Diesel eng where the old mule-drawn craft made « a fifth of that speed. They are expe to lend a stimulus to the development inland water-borne commerce, which faded somewhat with the growth of railroads. The boats are 260 feet | forty feet wide and have a cargo capac of 1883 tons. One of their chiei vantages is said to be the economy operation, only two engineers and t oilers being necessary. Electrically dri machinery aids in loading and unlodadi: They can navigate the Great Lakes in ¢ tremes of weather and when the ba: canal is closed by ice, they are transfer: to Atlantic coastal service. Bumper on Automobile Also Serves as Rack for Baggage ales Hi si “a Se Mined te Big enough for carrying trunks, m er ) Whic s rm- : 1] sie "fess Pevsone Sor Writing 4 Painting ' cans and other bulky objects as well spare tires, a rear-bumper carrying rack to which is attached a holder for pencils automobiles has been placed on the m or brushes. Fastened around the chest, ket. Besides space for these articles, t the apparatus can be easily directed by carrier has a bracket for the tail light a: slight movements of the body. The in- license plate, making extra attachmet strument can also be used to turn the’ unnecessary. It is bolted to the body a pages of a book or hold sketching ma-_ can be put on in little time. terials for drawing. It is claimed a person deprived of the use of the arms may be- come practiced in the manipulation of the device in a short time. When necessary, it may be adjusted to suit the heights of different tables or desks on which work is to be done. Where Toothbrushes Grow on Trees Stems from a West Indian tree that is rich in saponin, a soapy chemical that cleanses the teeth, are used by the natives instead of factory-made brushes in many parts of the islands. They are cut in sec- tions four or five inches long, and when the end is moistened and rubbed on the teeth, the fibrous wood becomes fraved and, at the same time, a profuse lather is produced. The brushes are sold in the native market at three for a cent. When driéd and ground, the wood forms a pow- der which is said to be good for cleaning dainty fabrics as it contains no substance injurious to them, How Milk Cans or Bulky Trunks Can Be Carried or ide Rear-Bumper Rack ~~ 156 POPULAR MECHANICS

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POPULAR 2 % S/1- 100;2eA a” Vy tee history records many great events since the discovery of Amer- few have done more to advance uman progress than the locomotive, the hundredth birthday of which is being ob- years + e rved this year. first public railway in the world opened for traffic in England on Sept. 1825. This road was built under par- mentary powers, conveying passengers ls It was a great ] ine well as coal and goods. when George Stephenson's historic comotive, preceded by a rider on horse- k carrying a flag, hauled a train con- ining thirty-four cars at a speed of ten » twelve miles an hour. While 1925 will be publicly accepted as rking one hundred years of railway peration, there will be a number of cele- I in the immediately following throughout North America. Con- cting claims have appeared as to what stitutes the first railway. In point of me the Pennsylvania railroad is the old- t in the United States by virtue of its irter being granted on March 21, 1823. did not, however, start to operate until pt. 20, 1832. Col. John Stevens is the ther of the Pennsylvania, as he is the ither of the American locomotive. Hav- t ations ng seen the imperfect steamboat oi John POPULAR MECHANICS MECHANICS >? Cr cr he becarn propulsion, and ex- for the next thirty Fitch plying on the Delaware, interested in steam perimented on this vears. In 1825, constructe/ locomotive with multitubular boiler whicl he operated for several years on a circular track upon his estate. It carried dozen passengers at the rate of miles an hour. This is believed to have been the first locomotive in America driven by steam upon a track. An example of the disbelief in the new steam traction is illustrated by a test of speed between a horse-drawn vehicle stevens half a twelve on an operating line of iron track and the first steam-drawn car staged at that time A mechanical genius named Peter Cooper had completed an engine known as “Tom Thumb.” fter months of endeavor he finally, on Aug. 28, 1830, got a trial of it on the Baltimore and Ohio road agai the regular horse-drawn vehicle ri engine quickly demonstrated its superio speed and power, and the new mode ot transportation was accepted. In years operation the Baltimore and Ohio is the oldest on this continent, and will celebrate While a steam rail 1825, its centennial in 1927 road was first operated in by this power date back as tat Between 1804 and 1825, the follow- engines driven 1804. is

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156 POPULAR ing inventors had been experimenting in England, France, and Germany: Watt, Cugnot He lle Blackett, Blenkinsop, ? lrevithick and Stephenson. imed built a satisfactory -w ork- ing engine in 1814, named “Blucher.” frevithick’s engine traveled on rails at Merthyr Tydfil in 1804. But it was only hat the steam-driven engine have been an important factor in aiding civilization. From this time on there was continuous progress in mechanical traction, and al- though the first were small ind crude, their emplovment as an agent yf transportation marks one of the world’s rreatest adv In the course of a this conti- ‘ , ocomotives ances. -enturv, a vast wilderness on anged trom gloomy un- nent has been ch inips and path- trodden forests, dismal sw less prairies into the abode of a high aie pee Prosperous states teeming h populous towns, fertile farms, ble ooming gardens and com- arisen from re- men and wild maintain sterile Stephenson's first lo- fortable homes have gions where savage animals united to desolation. Russian lectric Train Whi'ch Travels Distances of Almost 500 Miles without Stopping to Renew Its Supply of Current; Energy Is Derived from Large Motors Producing 3,000 Horsepower Each; Right, German Turbine- Driven. Locomotive, a Class Which Is Rapidly Taking a Place in the Field of Railway Trans- portation MECHANICS nder boiler only eig] feet long and thirty-four inches in dia: eter, with an internal flue tube pass through ee It had two vertical cylinde: and worked the prope ling gear with ers heads and connecting rods. The powe: of the two cylinders was carried by me of spurwheels to the drivers. Contrasted with this pygmy are gigantic types of the present ’ limited in size only by the capacities their axles. Marvelous steps in p and speeds have been accomplished practically no material growth in fuel c sumption over that of a short time In freight service iron monsters weig considerably more than 100 tons wit their tenders, attain speeds of from te1 fifteen miles an hour with fifty to a dred heavily loaded cars. comotive had a cvl which 1 With the Growing papas ity Oil as Locomotive 1 } Diesel Engine Has iy ™. duced for Rail Travel; This Is Late Model Exhibited at a Ra road Exposition in Berlin 158 POPULAR MECHANICS

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POPULAR MECHANICS 757 ene Serene enn = ae - a oie Reproduction of an Old Drawing Illustrating a Con- test between an Early Loco- notive and a Horse-Drawn R ailway Carriage; Right, Al- uugh Coal, Oil and E'ec- tricity Have Long Been Used for Modern Railroading, a Few Ancient Wood Burners Are Still Doing Active Serv- ice in Remote Districts Depending on Wood Which It Devoured at a Rapid Rate, This Old-Timer of 1853 Was a Mar vel of Its Day Below, Space Eater of the Type That Daily Races be tween New York and Chicago with Palatial Trains That Rival the Most Modern Hotels POPULAR MECHANICS rn ~C fuk

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708 POPULAR MECHANICS HAND JACK AND TACKLE DEVELOP SIX-TON PULL —ee Typical Uses of the Jack, Shown in Center Close-Up; Moving Freight Car, Hoisting a Heavy Stack and Towing Barge, Each with Only One Man For moving cars, clearing wreckage, set- ting boilers and many other similar tasks requiring heavy lifting or pulling, a port- able outfit that combines the principles of a jack and winch and can develop a direct pull of 12,000 pounds with one man work- ing a five-foot lever, has been placed on the market. It is mounted on wheels for €asy moving or may be carried on the 760 Fonr-Rladed ‘TI eviathan’’ Deanollorc shoulders of two workers as it weighs only a little more than 200 pounds. It has a drum that can be driven at six different speeds, while a brake and reverse mecha- nism insure control of the load. The ap- paratus is said to be especially practical in building jobs that do not justify installa- tion of power units, and its compact size adapts it to a wide range of usefulness. POPULAR MECHANICS Pheammendsete anew) ban eabies andi

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POPULAR MECHANICS 759 Plants Immune from All Disease Sought to Check Farm Losses Believing that the great losses annually licted by plant diseases on the world’s sod crops can be largely reduced by care- selection of blight-proof specimens, entists of the New York botanical gar- n urge students of botany and medicine combine in a search for such vegeta- nm. The report says it is possible many the ills afflicting mankind may be stud- in plant life. Diseases of great cereal ps are costing the country untold mil- ns of dollars each season. Wheat de- royed by rust in one year resulted in a ; of more than $20,000,000, and damage corn amounting to $5,000,000 was suf- red by growers in Illinois alone during -same period. While spraying, dusting seed treatment as now used are valu- ble helps in keeping down the losses, the pense of such processes is reflected in By breeding new and more turdy races of plants immune to blights, | developing those species which show esistance to diseases, it is hoped to in- rease the healthy crops and lower prices. rd costs. House Is Moved across Cemetery on Elevated Tracks On timber tracks raised several feet bove ground to avoid contact with the mbstones, a house being moved across n old California cemetery was safely ransported over the graveyard without the need of removing any of the monu- ents in its path. Before starting the huilding on the way to its new location, e mover mapped out a course for the supports between the graves. The runway was then elevated on blocks suffi- House Being Moved across Old Cemetery on Elevated Tracks to Avoid Damaging Tombstones ciently high to prevent injury to the plots or the plants growing on them. Chlorine Gas for Use in the Home Given by Adjustable Mask A gas mask which generates a mild mixture of chlorine and air for the relief Inhaler for Home Use Which Generates Chlorine Gas for Relief of Bronchial Ailments and in- charge of colds and bronchial affections, tended for individual use, has a sufficient to last several persons months. Equipped with a valve and regu- lator, the mask when applied to the nose can be easily adjusted to permit variations in the strength of the fumes. It is harm- less in its effect as the entire supply is in- sufficient to injure the patient. Used reg- ularly each day the inhaler is said to pre- infections of the ror two vent nose, throat and bronchial area, Gas can be consumed only while the valve is open. When the tank is emptied it may be recharged. Talking Tape for Indoor Aerials Strung on Molding or Frame A new form of indoor antenna, known as the talking tape, has made its ance. ] ippear- The tape is very flexible, and can easily be strung around the molding of a room or wound Oona wooden frame in t] S form of a loop. On account of tts flat sur- face it acts as an excellent conductor ot minute currents. POPULAR MECHANICS 761 °

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760 Four-Bladed ‘“‘Leviathan”’ Propellers to Give Greater Speed Propellers with four blades instead of lave been placed on the liner “Levi- 1 three | One of the New Propellers, and Engineers at Work Adjusting It for Installa- tion on the Shafts of the “Leviathan” athan,” to obtain greater speed and greater efficiency. The mighty “fins” are of bronze, weigh more than 35,000 pounds each and are over thirty feet in diameter. They were cast especially for the liner and carefully balanced before they were attached to the shafts so that they would run evenly, causing a minimum of vibra- tion. The ship has four propellers. Three Signs Occupy Same Space on Automatic Billboard An automatic signboard which displays three different advertisements in the same space is claimed to draw considerably more atten- tion than the ordinary out- door bulletin panel. Once installed, the board re- quires little or no care, as it operates by electric mo- tor and is so lightly con- structed that a great amount of energy is not neededtokeepitin constant motion. The panels of the sign consist of revolving triangular drums on each side of which equal sec- tions of the advertisement are painted. These rotate at intervals to present cor- HH 3444 444 POPULAR POPULAR MECHANICS responding surfaces to view and compos a complete design. When the signs ar to be replaced another set of drums mounted in the revolving frames, necessi tating but a few minutes of idle time t make the substitutio1 The device is said t work in all ki nds oj} weather. Similar dis plays may also be mack tor show-window and counter use in stores. More Forest Trees in Kansas Now The state of Kans has more forest trees t day than were foun when settlers took pos session of the territor according to Prof. Al bert Dickens, of t! Kansas State Agricul tural College, who sai when pioneers entere that country great tract of woods had been burne over by the Indians as a means of creati: barriers of waste land against other ho tile tribes. This repeated destruction r sulted in killing off most of the you: trees, and growths were confined 1 sparsely covered areas bordering on t! streams. Settlers prohibited the practic: and the timber began to spread. Hom steaders were then required by the gover ment to plant trees on each section of lan taken up. Many pioneers introduced seed which produced large crops of valuabl: lumber. Residents of the state are plant ing trees in available spaces and combine with the forestry patrols in preserving the timber stands by aiding in combating fires Automatic Signboard Which Displays Three Separate Advertisements on Tri angular Sections Revolved by Motor MECHANICS >

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POPULAR MECHANICS 761 * violet Rays Being Used on Child to Cure Rickets By F. N. HOLLINGSWORTH this ; year from whooping igh, and medical authorities rank this ise as one of the highest in the infant- lity statistics of the country. These res are necessarily incomplete, for ny communities do not class it as a rtable disease, and therefore keep no rds of it. As every mother knows oping cough is regarded as highly in- tious, and the periods when it is epi- cin a neighborhood are anxious ones them. However; ‘P BERE are over 6,000 deaths in ountry every an effective method of treat- nt, which, in the large majority of cases, roves a cure, and in practically every case cts great improvement, as well as ar- ‘ting the progress of the disease, has ‘n found, it is believed. In the last two ars, 700 cases of whooping cough have heen treated by means of the X-ray or entgen ray, at the “On-Shore depart- nt’ of the Boston floating hospital, th only two deaths, these being of ibies under one year old, where the dis- s¢é was complicated with pneumonia. » successful has this X-ray treatment roved at this hospital, where it was first ised, that it has now been taken up by nstitutions in New York, Chicago, San rancisco and Montreal. W hooping ugh is practically an all-year-round dis- ease, but reaches its peak between Janu- ary or February and June, according to weather conditions and the section of the country. If one has not had it in child- hood, it frequently seizes a person when full-grown, but having once gone through it, one is practically immune from a second attack, according to past re ‘ord It is among infants and very young ch dren, however, that the bulk of the cases occur, and death most frequently resu This new X-ray treatment ered entirely by accident, as it were, two vears ago. Everything had been tried the way of treatment with little success, and finally Dr. Henry I. Bowditch of the Harvard medical school, physiciat charge of the hospital, decided to try the Roentgen ray. It found that f fifteen to twenty per cent of the cases so treated showed prompt improvement, the convulsions stopping within twenty-four hours. The remaining eighty per cent cases treated in the two years showed det nite improvement, with the exception the two infant deaths mentioned above, The time of exposure varies in individ ual cases, according to the distance ot the ray from the patient, the thickness of the aluminum filter, and the strength or in tensity of the current used. Actual ex posure is from two to five minutes at each was disco Was POPULAR MECHANICS 763

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Usi X-Rz ith P ctive Alumi il Ww ing- ° - sing ays wi rotective uminum Filter on a at the front of the chest and the Cough Patient from Two to Five Minutes at a treatment, the “dose” being approximate- ly one quarter of the amount that would redden the skin of the patient. The ray is localized to the seat of the disease by means of a cone, inside of which is placed the filter. The apparatus used consists of an or- dinary high-tension transformer, with a Irrigating Dam One Mile Long to Water a Million Acres About 100 miles from Bombay, India, one of the largest irrigation projects in the world is nearing completion as the last rocks in the dam, one mile long and 170 feet high, are being put in place. The lake which age? Kiser heey will form will be eighteen miles long and forty-six miles in circumterence. Its waters would cover POPULAR MECHANICS rectifying device, a universal Cool- idge tube and a treatment stand with cones of such size and shap: as would include the entire ches: of the patient at a distance twenty-eight inches. The patient reclines on a couch during the treatment. When desirable, pa: ticular protection is afforded to the thyroid gland by covering t! gland area with sheet lead. Treat ments are every alternate day until three have been given, with a sim- ilar second course after an inte: val of seven days in more pr tracted and resistant cases. These additional treatments, howeve: did not seem necessary in most cases. The first treatment is given second at the back. Since t! whooping-cough germ has been isolated and is a well-recognized organism, an the X-ray method of treatment is a prove success, attention is now being given t finding out just why the X-ray effect cures and improvements. The ultraviolet ray is also used extensively in cases oi rickets and joint diseases. an area fifteen miles square to a depth o 143 feet, sufficient to irrigate approx mately 1,000,000 acres. If the rocks in t! dam were placed end to end, they woul reach haliway around the world. Tw canals, longer than the Panama, will di tribute the waters to the farms. At t! site of the dam, the rainfall averages on! forty inches a year, but the lake will ex tend to a district where the fall is mo: than six times that amount. Milestones of Engineering Progress in India, the New Irrigating Dam, Seen as a High White Wall Being Erected in Front of the Old Arched Structure at Right Courtesy The Sphere 764 POPULAR MECHANICS

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POPULAR MECHANICS 763 Artificial Sunshine in Zoo Keeps Tropical Birds Healthy ndon fogs, notorious for their thick- have often proved fatal to the more tropical birds at the London zoo. ffset the of the -customed dark- electric ps fitted fused- globes e recently en installed ovide arti- sunlight the bird e. Fused rtz, unlike nary glass, es not cut the ultra- et ravs, and fore dupli- the ac- effects of sunshine. ivy fogs e the trop- birds to — gin, off their l” and they sit and mope until they The artificial sunlight, however, ps them healthy and interested in food quartz lamps have also been found ful in the reptile-house laboratory to snakes and lizards to eat. The rep- make every effort to crawl into the e of the rays, and when there quickly ver their appetites. uette at Broadcasting Stat Two Hundred Inventions Daily : Reports of the patent office for 1924 ow that applications were received at e rate of about 300 a day and that some 2 ! were granted daily, including designs | trademarks. Those issued totaled 3.062, an increase of nearly 6,000 over 1923, and the number of applications was 101,134. The office reduced the number applications awaiting official action by rly 12,000 and lowered the average me to four and one-half months for new rk and to between three and four nths for old work. All fifty-four divi- ons of the office were less than eight onths behind at the close of the year, ile on January 1, 1924, twenty divisions ere more than eight months in arrears. dine YT ol i 1 Radio Fans Draw Wireless Picture Broadcast by Artist An interesting experiment was recently conducted by station WLAG by broad casting a silhouette of a profile photograph of Miss Eleat or Poehler, the managing di- rector. The listeners were instructed to draw thirty- five vertical and _ horizontal lines, spaced across a sheet of paper. The vertical | ines were desig- nated by letters and horizontal lines by num- bers. A profile photograph as then placed on a similarly ruled sheet a and a dotted outline was made. The ex- n Duplicated by Unseen Audience act location of each dot was broadcast so that the listeners could put them on their sheets and join them to form an outline duplicating the original, leaving the shaded portion to be filled in at leisure. Double Golf Tee Made of Rubber Provides Two Heights for Ball Golf tees with two sockets for the ball, one close to the ground and the other slightly higher, afford variations in prac- tice strokes, save time and promote ac- curacy in the use of the clubs. The tee is a bar of rubber, with a “well” for the ball at either end and a weight to retain it Adjusting Ball on Higher Socket, with the Weight near Lower One, Out of Club’s Range POPULAR MECHANICS 765

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764 POPULAR MECHANICS duce the cost of drilling, since surveyor: can gather data regarding the most fa orable spots and localities for sounding and its use may eliminate large numbe: of borings and exploration shafts both the search for oil and in ordinary minin,; By measuring the distances between poi where scale readings change, due to variation in the influence of gravity up by different minerals, the extent of t deposits can be quickly approximated. Autos Run through Ten-Foot Sewer to Carry Inaugurating Party About eleven years ago, the city of Bradford, England, began the construc tion of a huge sewage tunnel, three mile long and nearly 400 feet below the sur face. The work was completed recent and arrangements were made for the cer mony of laying the last brick. Then tl problem arose, how to get the inaugur ing party to the scene. The circular tu nel, ten feet in diameter, presented a stee and slippery bottom for any vehicle ar walking was out of the question. Seve motor cars were tried, but failed to mal

t, Unde & Underv l . : ss 1 Ss he Clock Wt ; A ical oe Rad the journey. Finally a concern maki: setting the ock Vhich tomatically Start ad ee = < Re , ; Set or Phonogra: h on C ynbination Instrument . light, small automobile offered to take t party to the tunnel center. Four c Combined Clock, Radio, Phonograph were used and, with skillful piloting, we: Gives Music at Anv ts sent through the sewer at the rate ’ twenty miles an hour without mishap. \ radio receiver, phonograph and clock have been combined so that the owner may have music at any predetermined hour. The wireless set has four tubes and may be operated independently, although

the clock is the heart of the apparatus. The entire instrument is sixty inches high, eighteen wide and fourteen deep. The radio uses dry cells and the phonograph is operated by an electric motor. It took two builders no less than five months to ] construct the instrument Balance Scale Finds Ore Deposits by Pull of Gravity Information concérning the location and size of subterranean ore and oil de- posits may be obtained by an instrument that makes extensive survevs and sound-

ings unnecessary. The device, consisting of a delicate balance scale, which has been demonstrated in Australia, also indicates the formation and structure of the earth at any given point for a considerable | depth. Application of the instrument toa prospected territory is said to greatly re-

J Auto Emerging from Its Trip through Sewer, Kept from Bottom Channel by Careful Steering

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POPULAR MECHANICS 765 - Nashing Air for : a \ HOME which is kept perfectly ven- tilated at all times with all windows ed, while the circulating air is washed of dust and germs and kept mois- ed or dried to a predetermined relative idity has been built in California by f. Willis Luther Moore, for more than hteen years chief of the United States ther bureau. ' nside the dead-air space of the usual e walls he has constructed a live-air ce through which the ventilating cur- t The live air, admitted through gister on the roof, passes through all walls and ceilings, and out again rough another roof register. ln addition there are two funnels on the f, looking much like the ventilators on ip, except that a vane keeps one al- s pointed into the wind, as an . pass. the humidity. After washing, the air goes down conduits running from the roof to each room in the house. The conduits have an inlet to each room through a small register placed in one corner of the ceil- ing, while in the opposite corner an out let register is located, with a conduit lead- ing to the exhaust funnel. The ventilation is so gentle as to be almost imperceptible, a steady, cool and moist current falling from the inlet regis- ter, and the used air rising on the oppo- site side of the room to the outlet. While the movement is almost imperceptible to the senses, an air meter attached to the inlet spins rapidly, as proof that consider able air is passing. Both the house and vard are equipped with thermometers and hygrometers to keep a written record of ike pipe, and the other away m the wind, as an exhaust. \fter entering the intake fun- on the roof the air is cooled passing through a series of n copper pipes that are kept et by a spray of water, the pipes ng covered with a fibrous ma- rial which acts like the covering an army canteen, cooling the inside through the water aporation on the outside. The pes themselves are located on roof, between the funnels, so t the passing air helps evap- ration. From the cooling coils e air passes through a series of ishing and moistening pans, hich wash it clean of all impuri- J ; : : : Air-Scrubbing Unit on House Roof with Intake and Discharge s and at the same time raise Funnels That Offer Path of Circulation for Wind Currents POPULAR MECHANICS °

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POPULAR pe Moist-Air Radiators Diffuse a Soothing Atmosphere and Can Be Easily Changed to Dry Heaters to Control Humidity the temperature and humidity. On a sample day the relative humidity out of doors was 31 per cent, while in the house it registered 79 per cent. The system is suificient to change the air in all rooms every forty minutes, or, by turning on an exhaust fan located at the roof, it can be speeded up to a com- plete change of atmosphere every eight minutes. Besides the novel ventilating system and the circulating live air in the walls, Prof. Moore has also perfected his own heating system, to insure the proper humidity in cold weather “Air that may be healthily moist when taken from the outside at a low tempera- ture, becomes harmfully dry when heated to a comfortable temperature,” he ex- plains. “Human beings suffer in this warm, dry air, suffer a depletion of nerv- ous and vital energy through the exces- demands made upon the ducts and glairds of the body to maintain its mois- ture. My heater is designed humidifying or moist-air radiator, which heats through the diffusion of water vapor.” } I sive a specially POPULAR MECHANICS The radiator consists of for pan units, each four feet lo: four inches wide and four inch: deep, through which pass the pips carrying the steam or hot wat: The pans, covered with fi screens, are partially filled wit water, the water level being ke constant by a float valve oper ing the inlet pipe. The steam hot water passing through t water pan gives off its heat, a: at the same time evaporate enough water from the open pat to maintain the humidity. T! valve arrangement is such tl the pans can be readily empti and the system changed to a d: air heater, if desired. “These radiators produce moist, soothing atmosphere, stead of the irritating and ner racking heat that comes from « dinary radiators,’ Prof. M: explains. “It is probable t! nothing conduces more to crease in the death rate than t! excessively dry air of the livi and sleeping rooms of winter climates where there a wid difference between the temper ture on the outside and that the inside, and the use of indivi ual heaters, burning up t oxygen of a room, and alwa lable to give off the deadly son monoxide. One may shiver and colder in an air seventy-five degree temperature and with a relative humidit of forty per cent or less than one wou in an atmosphere of sixty-eight degre with a relative humidity of sixty or se enty per cent. “The moist-air radiators in my ne home communicate heat largely throu, the diffusion of the water vapor rath than the radiation of dry heat, with a d cided gain in health and vitality, and marked saving in the expense of fu Moist air holds its heat and slowly los it, while dry air cools rapidly.” “Were the homes of the people that i1 habit the dry regions of California a the other states of the Rocky mountains he adds, “supplied with properly moi tened air, an enormous gain in healt and productive efficiency would come t them, and in all new construction pro sion should be made for installing a s tem for automatically and inexpensive washing and cooling the air in summ« and thoroughly ventilating every room a place ot habitation.” ? is cre gas Ti ' l¢ e MECHANICS

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POPULAR MECHANICS 767 Half of Nation’s Electric Power Now Used in Homes \lthough the first incandescent lamp not marketed until about 1880, the an- sale of electric appliances for the 1e is now estimated to total more than 10,000,000, according to a report of the tional Bank of Commerce in New York. total sales of electricity for residen- industrial and public-utility uses for t amounted to approximately $1,335,- 000, a sum $65,100,000 greater than that the preceding year. Of the electrical ds sold by retail stores, practically nety per cent is purchased by women. Motorcycle with Streamline Body Speeds Two Miles a Minute \Vhat is said to have been a world’s d record for motorcycles was made in lifornia recently when a four-cylinder ck machine, with special streamline dy and supercharging apparatus, covered uarter-mile stretch at the rate of 127.1 les per hour. The frame was shielded reduce wind resistance, the design be- made by one of the men who con- ructed the round-the-world airplanes, | the motorcycle was piloted by an ex- rienced automobile racer. Further at- mpts at lowering the speed mark are r Art Studios Motorcycle with Body Tapering Off Behind, Reducing Front Wind Resistance be made to test the machine’s equip- ment and the effect of streamline patterns. Pocket Pliers Shaped Like a Wrench to Increase Gripping Power Adjustable pliers that fit the hip pocket id are constructed somewhat like a mon- ey wrench, with protruding notched jaws r gripping round, square or hexagonal Holding Full Weight from Plier Wrench surfaces, Fixed to Nut, av 2 @ to Show Tool's have been om welts placed on and Safety the market from Slipping for mechan- ics, repair- men and others who desire a tool that will not slip and will stand great strain. A pair of this pattern is said to have greater capacity and more power than one twice its size and will bear 500 pounds’ pressure applied to the handles. By slipping the lower grip into its slotted groove, the jaws are quick- ly adjusted for articles of different size, and this feature makes the pliers well adapted to many tasks about the home. The jaws also can be adjusted to form an opening for closing tire-chain links. China’s Trade in Bones For many years, the economical Chinese have put animal bone to good use for vari- ous ornamental and practical articles and for fertilizer, but the traffic in this com- modity in recent times has greatly in- creased so that now they are said to be im- porting large quantities. During the first six months of 1923, Shanghai alone im- ported nearly 1,500 tons of cow bone val- ued at more than $238,000, principally for tile-egame makers. In 1922, China ex- ported more than $1,000,000 worth of bone. POPULAR MECHANICS 769

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,68 POPULAR Medicine Taken through the Skin to Avoid Unpleasant Doses With a new electrical apparatus, drugs and medicines, it is said, can be admin- Taking Medicine with the Electric Doser That Is Said to Force Liquids through the Skin istered through the skin, so that distaste- ful doses need not be taken through the mouth. The method is claimed to elimi- nate waste and secure more rapid action, as the substances do not pass through the stomach. The instrument is, however, intended principally for use in treating local ailments. have to Nation’s Seventeen Million Autos Valued at Ten Billion Dollars Official registration figures from all the states show that at the end of 1924, there were 17,700,179 autos in this country, an increase of about sixteen per cent over 1923. On the basis of a population of 114,000,000, this means that there is a passenger car or truck for nearly every sixth person. The money invested in the vehicles is estimated at $10,620,107 400. the to tal production for the year was placed at 3,580,- OOO cars, of which about 300,000 were exported. New York led in regis- trations with a total of 1,412,050, California was second with 1,321,480 and Ohio third with 1,237,000, closely followed by Penn- sylvania and Illinois, each MECHANICS Oil Drawn from Potatoes Reclaims Waste Unfit for Food A process for extracting oil from pot toes unfit for food has been invented Australia. Tubers in various stages decay may be treated to yield a colorle and odorless material especially valuab for lubricating delicate mechanisms su as are found in scientific instruments ai accurate balances. The low freezing poi: of the oil is said to make it adaptable al for airplane engines and _ instrument The process is inexpensive and simple an does not require large manufacturing tf cilities. It is claimed the method w greatly reduce the losses from spoilage i potato-growing districts by reclaimi: vast amounts of waste. Granite Block Cut from Mountain Is Forty Feet High One hundred thousand cubic feet solid granite were quarried at one ti! when a giant block was blasted from Stor Mountain, near Atlanta, Ga. Huge as t piece was, it represented but a tiny cl from the mountain itself, a massive mor lith rising some 1,700 feet above sea le and measuring nearly a mile from t base to the top. The steepest side of t] mountain is being carved with equestri figures of Gen. Lee and other southe: leaders as a monument to the Confed acy. The drill holes and the black burn leit by the blasting powder that tore th: big chunk from the cliff, are plainly vi ible on its end. with million tor vehicles. over a nlo- 770 Granite Block Big as a Barn, with Drill Holes Made for Blasting Showin; on Dark Surface in Center POPULAR MECHANICS

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POPULAR MECHANICS 769 Iwo Thousand Miles By Water Flivver nning with ay Hood for Stormy Weather Laid Flat By LEWIS R. FREEMAN \I \KING a 2,000-mile trip from Mil 4 waukee to New York with an board motor and an eighteen-foot skiff ers the lure of adventure and a way of oiding the discomforts, dust and con- tion of the motor highways. \s | had no companion, my transpor- tion unit was limited to one which I uld navigate and also take out of the iter alone if overtaken by storms. So selected an out- ird motor with an ribbed eighteen- vot boat. In order » keep from being rrced to shelter in rough weather, I had is craft decked over four feet back irom the bow, form- ¢ a closed, but not iter-tight forward impartment. After ebating the advan- tages and disadvan iges of a built-in isoline tank, with a ump to fill the en ine tank, I decided favor of carrying two spring-top three- / La Salle Raising the French one-gallon cans specially fitted with a three-foot length of one-inch hose for fill- ing in rough water. Also I added a can- vas canopy to throw off the water that vould find its wavy the decked-in | bow. This formed a f i combination ’ hood and extendable }" boat cover. It was 4 made of heavy water- proofed canvas, with fittings to button it to the coaming of the cabin and under either gunwale. Full extension of the cov- er was only intended to convert the boat into a dormitory This carried the can- vas all the wavy back over the tilted en- gine. Made fast along all the over spray wind- ward side and the stern, and with a lee corner open for ven tilation, the snug gest and most com- fortable sleeping , 4 Fla and Claim he 1 illon cans, and two eats g ry quarters imaginable POPULAR MECHANICS 771

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770 Se. en were ready. Provisions were the least of With cities and towns at frequent intervals along all but a hun- dred miles or of the way, and with many farmers and fishermen scattered between them, there was no need of carry- ing more than three or four days’ food supply at any time. j As something which might prove useful in emergencies, I carried a sixteen-pound mushroom anchor, but was lucky enough not to have to use it to hold the boat off an iron-bound lee shore on all the trip. A folding canvas bucket served the dual pur- pose of bailer and potential sea anchor, to be cast over at the end of a hundred feet of line to hold the head to the wind in the event of the disablement of the engine. Coming under motorboat classification, I had to carry two cork life preservers, a fire extinguisher and a foghorn to satisfy the regulations. As the lite preservers were not pleasant to wear, I stowed both where they would serve to sustain the boat in case of an upset and kept at hand a comfortable and fairly buoyant kapok jacket against possible emergency. I never used the foghorn for the purpose for which it was intended, but it did prove useful in trumpeting to drowsing lock keepers. The fire extinguisher was called into use only as a biscuit-dough roller. Except for one heavy thunderstorm of semicyclonic character, of which I only caught the tail end above Sheboygan, the first four or five days following my de- parture from the Milwaukee yacht club were either windless or of light and vari- able breezes. In easy comfortable runs of sixty to seventy miles a day, | ran up along the pleasant sandy shores of the my problems. SO ~? ~> 72 POPULAR MECHANICS POPULAR MECHANICS Dredges Are in Long Lines, Busy . Keeping the Waterways “ee Open for Navigation Passed west coast of Lake Michigan, through t! Sturgeon Bay canal to the limestone-c! walled Green Bay. From Manistique, I started off along t! direct steamer track to the straits Mackinac, eighty miles as the crow fli Running at an easy seven and eight mil an hour, I skirted the coast fairly close for thirty miles. Then, with the sky sti clear and the stiff following wind on serving to accelerate my progress, I hea ed out on the steamer track. By noon, t! low northern shore was a misty strea abeam to port, with the rapidly develo; ing sou'wester driving up a white-capp« sea that splashed a disturbingly genero1 amount of water over the starboard qua ter. Another half-hour, with solid gree: water coming over at every lurch and bot hands so busy at the lines of the kickins tiller that they were only available for 11 creasingly infrequent dabs with the ba: ing bucket, I turned and headed straigh' before the wind and seas for the di: blurred line of the shore. Running directly before the wind, t! seas decreased for a while the rate which water was coming over the side, but at the same time started a violent yawin: which increased the risk of an upset. M bailing-bucket sea anchor performed nob! in holding the head to the wind when dying cough told of an empty tank, an the gallon can and tube worked precise! as planned in refilling. With no chance

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POPULAR MECHANICS 771 ers, I laid to my oars and ran in through the surf. My boat was rather more than halt filled before | had dragged het to a point where the spent combers ceased to menace het The next day, after running a couple of miles across a mounting beam sea, | rounded a jutting point Passenger Steamers Pe, ew Are Met Every- where Going up down the Lakes . unroll and consult my irt, it was not long before position became very oubttul, and only more rply breaking combers re- ealed the presence of the ry extensive reefs and oals I knew to exist on every side. Nothing in the ay of a bay opened up as e line of the coast became more distinct, so that the only thing left to do was to pick the least forbidding tretch of beach and head in tor it like a gull at a gate. With rocks fanging the breakers almost all of the way along the slightly curving shore line, a hundred yards ot sandy beach offered at the last the best chance to avoid mashing up before my boat Vas near enough to drag out. Shutting off and tilting the ~ 4 otor at the outermost of a ~ 300-yard side zone of break- + POPULAR MECHANICS 773

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772 POPULAR MECHANICS to find a protected mooring behind the crumbling breakwaters of the half-ruined town of old Naubinway. Here I was held three days and a half before an abatement of wind and sea allowed me to put out again, and even then a squally afternoon held me down to a short fifteen-mile run to quaint Epoufette. The next day I ran forty-five miles to St. Ignace and historic Mackinac Island, where again a hard sou’- wester kept me in port for a further twenty-four hours. The next day I started early and, eating both breakfast and lunch in the boat, ran continuously until the late afternoon found me at Cockburn Island, and for the gern, A LS Ser ee Vere. - \ first time in Canadian waters. Both tl! chart and the fact that my sixth gallo tank of gasoline was half exhausted ind cated a day’s run of over eighty mile much of it through the reef-foul wate: south of Drummond Island. There was a menacing turret of clou boring in from the southwestward as I ra: through False Detour passage, rounde the northwestern cape of Cockburn Isla: and tied up in the lee of a shambling o! lumber dock. After three days’ delay du: to bad weather, the ninety-mile run t Little Current, at the mouth of Georgia Bay, was made ina day. The Trent cana! utilizing a series of lakes and rivers alon; the route of one of Champlain’s early line of exploration, connects the lower end o Georgian Bay with Trenton, about sixt miles above Kingston, which is itself the end of the last of the Great ~~ Lakes and the head of the St t Lawrence. This waterway i \ 250 miles in length, and ove: forty locks of the ordinary ash tvpe are passed, as well as tw The Old French Blockhouse on Mackinac Island Still Stands above the Straits Where Once the World’s Fur Trade Was Fought for by French, English and Later, Americans ~ ~2 pe POPULAR MECHANICS

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POPULAR reat lift locks and two marine railways he Bay of Quinte, which I traversed im Trenton to the Thousand Islands, is swept by violent southerly winds, so hat I had a very rough run. The winds hitted to northerly as I emerged from he Thousand Islands, and I had to beach twice to keep from swamping. By run- ing the comparatively easy upper rapids the river instead of wasting time in the cks and canals, I had no difficulty in aking the 180 miles between Kingston and Montreal in not much over two days’ unning time. he Big Soo rapids and the Cascades have some heavy water and I felt safer n passing them by the canals. Lachine vould have been easily runable, but I had o follow the canal inorder to reach a mooring near the center of Montreal. Here | replaced a battery for the first time, one cell having served for the entire 1,500-mile run from Milwaukee. It was eakened but still, in an emergency, could ive served quite a while longer. \ run in fast moving water carried me irty-five miles down the St. Lawrence to the mouth of the Richelieu at Sorel, vhich beautiful and historic stream I fol- wed for a hundred miles to its source n Lake Champlain. Ten old and pictur- esque locks lifted my boat over the more precipitous stretches of a stream which ? MECHANICS 773 The Canal Lock Rises Un and Trundles the Boat over the Hill be- tween the Severn River and Trent Canal, an Unusual Marine Railway has been a highway of travel and com merce since the French first settled in Canada. Passing the American customs at Rouse’s Point, I ran over a hundred miles before a northerly wind up Lake Cham- plain in a single day. The following after noon I entered the Champlain canal at Whitehall, and passed a series of locks which carried me by the New York barge canal to the Hudson. Passing through the lock at Troy, I found my boat drawn sea- ward on the outgoing tide, which has a rise and fall of several feet against the first of the Hudson’s dams, 150 miles from New York. After spending a Sun day in Albany, I resumed my voyage the following morning. Three days later —which included a day's lay-over at Tarry- town—I headed into the swiit tide of the Harlem, bucking it with my still steadily hitting little motor until Hell Gate was passed and I had won my way to a quiet mooring at a boathouse under Flushing bridge. In looking back on what was beyond “doubt one of the most interesting and enjoyable trips I have ever made, it seems to me the most significant fact about it ts the one I cited at the outset—that it was made with an outfit any good outdoor man could buy and run. I only hope many of them will. POPULAR MECHANICS t75

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774 POPULAR MECHANICS Mail Box on Front of Street Car Speeds Up Collections Letter writers of Barkingside, Eng., who miss the postman’s calls with their mail can insure its delivery on schedule time by depositing it in a mail box attachedtoa street car which makes regular trips to a post- al center. Passengers with matter to be © P. & A. Mail Box on Front of Trolley Car, Which Hel_s Speed Collections of Postal Matter posted are saved the trouble of seeking a letter box on their way to the car line by having the parcels carried to the exchang- ing points by the same trolley they ride in. Aiter the last collections for the day are taken up in the district, the street-car mail box is available for an hour. Rubber Link Chains for Auto Tires Chains with long cross links of rubber and fabric instead of metal have been offered for use on auto tires to stop skid- ding and eliminate the clanking and rattling of the usual equipment. In the ends are vulcanized small metal fasteners that hook into the long chain sections and hold the rubber snugly against teen links are needed to encompass Neater appearance, longer wear as well silence are claimed for them. Great Salt Lake Waters Expanding Weather Bureau Finds That stranded ocean of the desert, t! Great Salt lake in Utah, is reported by t! weather bureau to be passing throug another period of expansion. The wate: are rising over railroad tracks, farms ar highways near by, and are causing co: siderable trouble. The movement is n a new phenomenon, for between 1850 a: 1870, the lake area increased from 1,750 1 2,170 square miles. Since then, its le has been falling, but now the action is r versed. With these changes, there ha been variations in the salt content betwe¢ fourteen and twenty-two per cent. TT! present average depth of the lake is sa to be six feet four inches. Swing Rocks Like Boat on Waves Providing Fun and Exercise Amusement and healthful exercise a: afforded children by a patented swingi: hoard suspended on arms attached stout posts anchored in concrete on t! playground. From two to ten may rice at the same time, operating the board | alternately pushing and pulling on tv side rails that extend the full length of t! swing. An easy, gliding motion forwa: and backward results, giving somew! the same sensation as that produced by) boat dipping over large waves. the tire. For a four-inch tire, only twelve or four- Six or More Children Can Ride at Once on This Long, Rocking Swing Sus pended between Steel Posts 776 POPULAR MECHANICS

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POPULAR MECHANICS t75 WHAT “SUPER-POWER” MEANS IN BROADCASTING High-power” radio nsmitters have been talled at five broad- ting stations in vari parts of the coun- as an answer to the ind for wider range improved quality in eption. They are : “a Pa = | i rl ‘ Ami )a0000008 High-Power Transmitter at Station WCBD; Left, Power-Amplifying Tubes and Water-Cooling Coils; Above, Using Wave Meter at Tuning Unit and View of Control Board . 5,000-watt sets, this measurement being on the basis of the amount of current that reaches the broadcasting antenna. But uch a set delivers into the air only about 2000 watts, or the practical equivalent of about three horsepower. The rest is lost, mainly through heat radiation. Hence a station with a set that may cost $60,000 or so, is delivering in usable form only about one-sixth of the power of a Ford engine. In other words, it would ike more than six of these transmitting lants working together to deliver as uch power into the air as is furnished by a “flivver” on the road. While the ransmitter may be receiving 22,000 watts rom the generators, most of this power lips away before it reaches the antenna lor its journey through the air. Heat and ther losses affect smaller sets as well, so that this limitation is not peculiar to the POPULAR MECHANICS high-power station alone. It only shows in greater proportion Ship Gets More Speed on Less Fuel with Dummy Propeller To overcome the loss of speed and fuel resulting from the churning set up by a ship's propeller, a fanlike device with fixed blades has been designed to increase the resistance of the water. The vanes, by acting against the agitation ot the water, cause it to present a more solid mass to the action of the turning giving the propeller blades a stronger hold. In a test, the apparatus, which is located on the rudder post, is said to have caused a saving of one-sixth of the fuel usually required and an increase of ten per cent in the vessel's velocity. swirling SCTeW, 777

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anf i76 POPULAR MECHANICS Electric Cigar Sorter and Matcher Handles Four Thousand an Hour Cigars are sorted at the rate of 4,000 an hour according to the color of their wrap- pers by an almost human electrical ma- chine that is said to do the work of eight i \ Cigars Falling into Various Bins from Hopper as Sorter Detects Differences in Color men and can handle thirty-two different grades at once. Its secret is the marvelous power of a photoelectric cell, such as is used by astronomers in determining the intensity of the light of stars and in some apparatus for sending photographs by wire. This cell generates electricity pro- portional to the strength of the light that strikes it. In the machine, it is adjusted to receive rays from four electric bulbs aiter thev have been reflected from the wrappers of the cigars. Dark tobaccos absorb more light than do those of bright- er shades, so that the amount of current gen- erated in the cell varies according to the color of the cigar. An amplifying tube “boosts up” this cur- rent sufficiently to oper- ate switches that cause the cigars to fall into dif- ferent bins as they pass from a common hopper. The sorter is said to de- tect delicate differences in coloring that human experts would not no- tice at first glance. It is suggested that the prin- be used in sorting bolts of cloth, butt: dyes and other products that are clas hed according to differences in color. Decay in Stone Buildings During an inspection of 200 stone buil: ings by the bureau of standards, it wa found, in several cases, that the materia had decayed, apparently from recrystal! zation of soluble substances which ha leaked out over the surface or mortar an had been deposited on top of the stone « slightly beneath it. The expansion of tli crystals, it was decided, had produce somewhat the same effect as frost, brea! ing off tiny particles. The same result were duplicated in a laboratory by part! immersing stone in a weak solution o sodium sulphate. The salt was absorbe through the pores and appeared again i: crystalline form on the outside or withi: the samples. The decay was said to bx most noticeable in sandstone buildings. Memorial Shrine to Motherhood to Be Built at Capital An elaborate memorial shrine in hon: of motherhood is to be built in Washins ton, D. C. When completed the stru ture will cover a large plot of ground in prominent section of the city, and w form an attractive addition to the gre number of similar buildings that are vi ited each year by throngs of tourists pas ing through the capital. The cost ot t! shrine, which is sponsored by the Wo: en’s Universal Alliance, will be paid fro: a fund subscribed by people from all par oi the country. Accommodations will provided the buildi for both and outdo gathering and a speal ers’ stand wi afford a clea view of th-« terraced step- s , , Sculptor at Work on Miniature Model of Memorial Shrine to Motherhood ciple of the device could Which Is to Be Erected in the National Capital 778 POPULAR MECHANIE€S

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POPULAR MECHANICS 777 tat dbo SARE AL ow v Pick Uour New SAGUYT ARE A A Radio Set | By E. A. BEANE Supervisor, Ninth Radio District YICKING a new radio receiver, to build or to buy, involves other considera- ms than whether the cabinet matches the furniture and there are enough dials and knobs to satisfy a longing for experimenta- tion in wireless. Unless the pro- spective owner has decided first in his own mind what he wants the receiver to do, the chances of satisfying him are slim. One set will bring in the distant sta- tions, while an- other features loud-speaker volume, and still a third is remarkable for the clarity of its tone. Some super-sets may com- bine all three, but the price will be cor- respondingly high. Then, too, there is the question of where the set is to be used, the type of construc- tion of the building, its location in refer- ence to neighbors with regenerative re- ceivers, its nearness to high-tension power lines, street-car trolley wires, elevated cars, electric-light power houses, doctors and dentists using X-ray equipment or violet-ray machines, and whether the building has electric elevator equipment. \ll these factors will influence the results, and should be considered in selecting the type of receiver to be used and its equip- Sie: E. A. Beane POPULAR MECHANICS ment. For example, most portable re- ceivers and some of the non-portable sets are built with loop aerials, either incor- porated in the equipment or connected to the exterior of the cabinet. But if you are going to use the receiver in a building with a steel frame, of reinforced-con- crete construction or with metal lath in the wall, you can’t expect to get extreme distance or much volume from the inside loop. The steel of the building and the metal lath of the walls act as a giant cage, absorbing a good part of the radio waves which otherwise should enter the room. The loop will work local stations under these conditions, but for distant stations an outside aerial is desirable. An electric elevator in the building may cause an endless amount of annoyance, particularly if an inside aerial is being used. Every time a circuit is made or broken by the starting and stopping of the car, the fact may be recorded by unearthly howls, squeals and groans in the receiver. A high-tension power line, even though it may be many city blocks away, is a po- tential source of interference. Just the other day we began to receive a flood of complaints from a city district covering several square miles. Every radio owner in the section apparently called up to re- port that some amateur operator had got- ten clear off his wave length and was send- ing code all over the dial. Each complain- ant reported the amateur was on a dif- ferent wave length, ranging all the way from about 200 meters up to well over 500. When the reports persisted for two or

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i78 POPULAR MECHANIE€S three days, we went out with a direction- where there are eight or ten powerfu finding set and started to run the trouble broadcasting stations, five or six-tube out down. It was finally located on top of fits may have trouble tuning out the loca an electric-light company’s pole! An in- broadcasters to bring in the distant outfit sulator on the 33,000-volt line had broken ‘The city man. who has to work throug! down, and as the power surged over the near-by local broadcasters and wants ti gap to the ground, it sent out a wild get distance, should decide on a receive: jumble of dots and dashes which, to with five or more tubes for best result people who can't read wireless code, or else should be thoroughly convince sounded like an amateur sending. Even by demonstration that the set will tun the best receivers are not out the local stations. proof against that kind of If volume is desired, the first thing t « interference, but they will consider is the size of the room in whicl get around much of the’ the receiver is to be operated. For ordinary annoyances of small room, the average city-apartment living room, for example, a two-tube set will give sufficient volume to operate loud speaker on local stations. If the room is a large one, or has big archway connecting with adjoining rooms, three tubes should be the minimum on local sta tions for loud-speaker volume. One man who moved from a small apartment int another with much larger living root blamed his two-tube set because of de creased volume, and insisted it had gone bad. He bought new tubes and batteries but still didn’t get results. He had simpl failed to consider the changed acousti properties of his home. If both distance and volume are desired, nothing less tha: six tubes may be expected to give results. For the man who want clarity of tone, and doesn’t cart particularly about great volume or extreme distance, a set en The Salesman May Be a Glib Talker When It Comes to “Low Loss” and “DX” but a Store Test Is Not Always Convincing reception in the heart of a big city. On the basis of 100-per-cent perfection in reception the best set on the market may be said to be about eighty per cent effi- cient, the various other circuits grading down accordingly. These figures are only approximate. Variations of standard hookups and some trick circuits get re- sults far above the average of their cost class—and then again some trick circuits rate well below the average of sets of corresponding cost. If vou want to get great distance, the first thing to consider is your location. In part of the ninth district—up in the Da- kotas, for example—owners of two and three-tube receivers have no trouble in picking up stations from New York to Los Angeles, even in the daytime. On the other hand, in a big city like Chicago, 780 POPULAR MECHANICS

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POPULAR oving resistance- upled or impedance- supled amplification, in- tead of transformers, is enerally considered the st. A receiver of that pe must employ at least ur tubes. Much de- however, on the ud speaker used. A set which the tone was ery “fuzzy” when em- If You Build Your Own Set Use Only the Best Parts and, If It Is an Ad- vertised Hookup Stick to the Parts and Dia- gram _ Recom- mended by the Designer ends, oying a loud speaker th large horn, and hich could not be im- roved by experimenting th the set, was cor- ected aS soon asa loud eaker with.smaller orn was put in use. In any set built or ught to bring in distant tations, selectivity hould always be consid- red. Itis not enough to » into the store and see e clerk bring in a roadcast station 2,000 les away. The ques- n is, will the receiver k up two distant sta- ms on virtually the me wave length, sepa- te them and bring in ier with clear tone d without interference ? he best of sets, how- er, will not operate tisfactorily in the ng surroundings, or with the wrong | of aerial. I have an eleven-tube re- ver which is as nearly perfect as any set ive ever seen. Its volume is not par ularly great, but it will take any present oadcast frequency and reproduce with most perfect tone, with perfect selec- itv, and it gets the distance. I brought down to my office, however, and could ily get two local stations, one across the reet and the other four blocks away! wo other local stations, not much more lan a mile distant, could not be heard ven on eleven tubes. That shows what uilding construction, elevated electric nes and street-car trolleys will do to a receiver. Lhen, the nearness of neighbors with egenerative sets will affect any outfit. As this type of receiving set is ermitted, or bought by radio fans, the rouble will continue. The bureau of tandards found that an oscillating tube in regenerative circuit could cause inter- ong as MECHANICS ference for a distance of nine miles around. I have seen an ordinary receiving tube used in a transmitter, and it worked from St Louis to Savannah, Ga., a distance of around 500 miles. Sut take the bureau of standards’ nine-mile figure as servative estimate and figure out many regenerative sets are within that radius of your home, all of them ben potential sources of annoyance. In a bi city, 100,000 probably would be a cor tive estimate. The neighbor's regenerative set is re sponsible for most of the complaints we receive against various broadcasting sta tions. Calls come in that some local sta tion has “broadened” its wave or is clear off its proper length and coming in at a other place on the dial. Yet with 195 broadcasting stations in this district (be 3,600 amateur operators) never found an authentic case of a wave length being broadened Invariably the complaints may be traced down to a re- sides we have POPULAR MECHANICS isl

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780 POPULAR MECHANICS generative set. Its owner tunes in on some near-by local station, and because of the volume of the broadcaster he detunes his receiver a bit, instead of regulating his tube voltage. The result is he is picking up the station several degrees off its nat- ural wave length, and is rebroadcasting through his regenerative set, heterodyn- ing the signals up to some other wave band. The effect is to “beat up,” as we call it, the frequency of the sending station, until all the neighbors are picking it up, not on its normal wave length, but in the wave band to which the fellow with the regenerative set has heterodvyned it. When that happens the man who finds himself unable to tune what he thinks is an offending station out of the wave length of somebody else he wants to lis- ten to, calls us up and either complains of wave-length broadening, or blames it on the broadcaster’s harmonics. It is very easy to tell whether you are getting a har- monic wave, since they occupy fixed bands. Going down the dial the first harmonic is just one-half of the true wave length, the second one-half of the remainder, or one-quarter of the true wave, the next halves it again, making the third harmonic ae one-eighth of the wave, the fourth is one- sixteenth, and so on. There are no up per harmonics which can be picked up b any instrument yet made. All other wave you pick up off the wave length are th result of regenerative interference. If you do buy or build a regenerative set, learn how to tune it sharply and t keep it from oscillating so you are not sending out false signals. And if a neig! bor bothers you, perhaps you can pa your tuning information along. A good part of all the troubles encoun- tered in- operating receiving sets may be traced to poor tuning. If the maker's directions are followed carefully, most oi the trouble can be avoided. It may take weeks to learn all the peculiarities about any given receiver; one will give a di tinctive click each time the tuning dial pass over a station, and another may i dicate the same thing by a squeal or whistle, or possibly not at all. To g results you have to learn each of those dis tinctive quirks of your receiver. Lots oi radio fans talk about turning the dial and having station after station pour in on the loud speaker. May be they do, but usually it takes patient tuning for each one. There Is Nothing Like the Thrill That Comes When a Home-Built Set Is Connected Up and Brings in the Broadcast at the First Trial 782 POPULAR MECHANICS

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POPULAR MECHANICS isl FIRST-AID STREET BOOTH HOLDS STRETCHER Kompiette Einrichtung Krankenhausern “Laboraiorien ~ ews of Emergency Sta- Where Help May Be 1 in Case of Accidents ng Before Ambulances Arrive from Hospitals; cemen Opening First- 1 Booth; Physician specting Supplies and ling Stretcher in Use Conveniently placed near busy ntersections, ontain a street public first-aid booths that folding stretcher, bandages, edicines and other necessary equipment have been erected in Berlin to aid acci- dent victims. Before an ambulance can reach the scene, this handy station may be called into service and perhaps lives saved by the timely use of thé implements it rovides. A public doctor of the city iftety service regularly inspects the stock supplies and the booth is at all times iccessible to police or laymen when emer- sencies arise. Occupying but little space, not hinder traffic it does moved easily and quickly. Turtle Farm Earns Profit What is said to be the only turtle fart in Iowa is located near Fertile, Wort! county. The owner has built up a profit able business in supplying homes. The snappers are caught nets or in traps during the summer and kept in underground stockades, being ted on minnows until they winter months. are and can be hotels and with ] sold in the POPULAR MECHANICS 78:

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782 POPULAR MECHANICS “ ve otras AY ht Pye. ANE Sas wi - rey AL How Animals Take Their Naps Various kinds of al mals assume widely d ferent postures wh they sleep, and from the habits in slumber scie1 tists are able .to lear interesting facts cor cerning their nature The dog, for instance, said to curl around eral times before lyin down because that wa its habit when it was jungle animal, to fort the grass into a comfort able cushion. Sma monkeys of various kind sleep on their perche with their fingers tight! closed as though holdi: on to branches. Giraffe lay their necks alon their backs when the slumber. Horned an mals, such as deer, kee; their heads in the usu waking position an many horses do not ‘down when asleep. Bear lapse into slumber in a most any posture, th sloth sleeps upside dowt hanging by all four feet from branches, and tl Ancient Royal Barge of Turkey Stored in Naval Drydock; Moorish Design and Requires.144 Oarsmen to Propel It Ancient Royal Barge of Turkey Placed in Naval Drydock The royal barge of Turkey, built 280 years ago and used especially for the sultan and his family during imperial cere- monies, has been placed in the naval dry dock. The boat, which requires a row- ing crew of 144 oarsmen, is of Moorish de sign and is covered with elegantly carved woodwork. All the ornamental attach ments were formed with hand tools by skilled craftsmen, who displaved their art in the construction of the deck canopy. The vessel weighs 110 tons and provides for a row of thirty-six double-banked oars on each side. The enormous beams were each manned by two rowers. The ship is built in the form of a caique, a type of light boat peculiar to the region of the strait of Bosporus, and such craft were once employed extensively for carrying passengers. 734 anteater covers its bod with its tail, while the b takes a nap with on! one claw to support it and its wings fold to make a light and waterproof tent ov« it. Creatures with short legs, such as t! pig and the hippopotamus, for instance: lie on the side when sleeping. the Vessel Is of Tons of Tallow-Dipped Steel Wire Bind Bridge to Concrete Base One of the most vital units in the gr« Delaware river bridge between Philade’ phia and Camden, N. J., is the pair of mas sive concrete anchors on either side t which the cables that support the struc ture are attached. tach contains abou 75,000 cubic yards of material in whic! the long steel tie-rods that hold the sepa rate strands are imbedded. In all, 25,00 miles of wire, weighing 7,100 tons, wet used. Tar and tallow were smeared ov each of the 18,666 individual wires in ea¢ of the two cables to prevent rust. POPULAR MECHANICS

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POPULAR MECHANICS 783 An End of United Mass of Wires Drawn Together in Powerful Press at = the Anchorage J — a n> j j j » / Units in Cable Fastened to In dividual Su p- orts and Then Joined as Single Huge Rope to Stretch across River Bundles of Separate yi | Wires Ready to Be Squeezed j Above, View of Concrete Ar chor Blocks and Steel S$ ports over Which Cables A Stretched wnomrynoyeyry avs agrwsersewwrrearr

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784 POPULAR MECHANICS Aviators Surveying Railroad Route Find Hidden Mountain Pass A surveying party traveling by airplane over a proposed railway route in the prov- ince of Quebec, Can., discovered an un- known pass in the Abitibi mountains, which resulted in their changing the course of the line to a better and shorter one than that first measured. Although the road was laid out by a land group of surveyors, it is said the information gathered by the flyers will make possible a great reduction in operating costs of the completed system below the expenses es- timated in the original plans. After the first survey was finished, the engineers de- cided to make a supplementary inspection of the route by air to check up the earlier charting. @ Whenever you find that you wish to know more about any article in the maga- zine, write our Bureau of Information. "86 POPULAR Pigeons Taking Flight from Their Airplane Coop eft, Opening Compartment Doors to Release Birds Flying Pigeon Coop Carries Birds to Races in Belgium Racing pigeons entered for flying con tests by a group of Belgian fanciers ar: transported to the starting points in an airplane fitted up as a comfortable coop Each team of birds is inclosed in a room compartment separate from the others and on arrival at the destination, all are released at once. The pigeon house i constructed in the fuselage of the machine with entrances on the sides, so that eac! cage is well ventilated, insuring the best of traveling conditions for the flyers. This method of carrying racing pigeons to b “tossed” is said to greatly benefit the little contestants. Several hundred birds ca be carried, relieving them of the strain 01 crowded quarters on long overland trip Young Mosquitoes Starved to Death by Poisoning Their Food sy putting chemical into ponds wher mosquito larve are growing, scientis* are reported to have found a way to de stroy the minute forms of vegetable an animal life on which the “wrigglers” fee and thus starve the mosquito to death 1 its early stage. This method already ha been used successfully in New Jersey. T] poison is applied in quantities too sma to injure fish or plants, and because s little is needed, its economy is an addi tional point in its favor. MECHANICS

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POPULAR MECHANICS Sahara Express Offers a Variety of Modes of Travel The Sahara express run on regular ice-a-week schedule from Paris to imbuktu in West Africa, includes travel boat, automobile and tractor as well as \fter crossing the Méditerranean by teamer, the journey, which takes twelve ivs, is by way of the Sahara desert where both wheeled automobiles and tread trac- rs compose the train to cover the hot, indy wastes. This part of the trip re- iires three days, after which the travelers re taken in speedy motor cars as far as the Niger river, where the last stretch of 100 miles is made by boat. Hotels are established at the end of each day’s stage nd numerous stops are provided for rest. Among the hostelries are two old castles hich have been furnished with bath- rooms and other modern equipment for ccommodation of the travelers. Since the route passes through wild country in- ‘ested by bands of marauders, the trains ire equipped with machine guns to repel attacks from hostile natives or tribesmen. Aerial Supports of Metal Improve Reception and Aid Grounding \ practical support for antenna wires is now available, which may be used for sup- porting a single strand, or an aerial con- sisting of several wires. The support, vhich is strongly made of metal, offers a place to mount the lightning arrester here it is most effective. It is claimed to assist in the elimination of static by pro- viding a direct uninterrupted path to the eround for this disturbing element, to aid in clearer reception, and permit greater distances to be covered. It eliminates the use of wood and nails, and does not de- tract from the ap- pearance of the building. When mounted on frame buildings, the an- chor screweyes on the end of the safe- ty chains or braces are screwed firmly. into the wood, and when used on brick buildings, the screweyes are pro- vided with expan- sion shells which are placed firmly 785 Typewriter Balanced in Desk Is Easily Moved A stenographers’ desk with a top of the vanishing type has the elevating mecha- nism arranged to balance the weight of Typewriter Desk Which Bal- ances’ Weight of Machine So It Can Be Raised or Low- ered with Hardly Any Effort the typewriter so it can be raised or low- ered with hardly any effort. Instead of the operator lifting the weight of the ma- chine in opening the desk, the platform holding the typewriter glides smoothly in- to place as the top is swung back. With this counterbalanced design, injurious jarring and bumping are eliminated, and wear and tear both on desk and machine are reduced materially. Tobacco Is Tested with Mirrors to Detect Adulterations Testing tobacco by means of mirrors is the plan an English expert follows to de- tect impurities. He uses a large glass or several smaller ones, and polishes them until not a trace of dirt or moisture is visible. The tobacco smoke is then blown upon the surface until it becomes clouded. If the moisture evaporates without leaving any mark on the glass, the condition of the to- into holes drilled in the brickwork. Job, an mma rere Tr Ul OF Substantial Metal Supports fos the ee me a Neat re Easy to Insta acwanmewryrafétékTlUmvrlhUOr bacco is regarded as satisfactory teh”)

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786 POPULAR MECHANICS Widespread Use of Radio Shown by Big and Little Tubes Two extremes in radio tubes, a gigantic silica unit employed in a transmitting sta- tion and capable of taking a filament cur- Extremes in Radio: Giant Silica Transmitter Tube and Small One Common in Receiver Sets rent up to fifty amperes, and one with a capacity of only a quarter of an ampere, were displayed at an optical exhibition in England, graphically illustrating what dif- ferences in equipment have become neces- sary through the widespread popularity of broadcasting. The larger tube is said to have cost nearly $750 and can take a fila- ment voltage of thirty and a plate voltage of 12,000. Science to Manufacture Blood? Man’s supply of red corpuscles can be increased by application of a preparation made from spleen and bone marrow, ac- cording to Dr. Chauncey D. Leake, of the University of Wisconsin, who recently told the American Society for the Ad- vancement of Science of successful experi- ments on rabbits, dogs and human beings. The experiments indicate the effect is due directly to stimulation of blood produc- tion, and to the fact that the combined spleen-and-marrow extract increases the resistance of the red-blood cells to de- structive and weakening agencies within the body. Dr. H. G. Barbour, of th: University of Louisville, at the same ses sion gave scientific approval to the fic tion writer’s cherished phrase that “fea: and terror curdled the blood in his veins. By applying a new method of measuring the thickness of the blood, he found that fear or excitement. may cause the blood t. become ten per cent more concentrate: within ten minutes. Wood-Saving Fluid Prevents Decay and Ends Blue-Stain Losses Blue stain, which has caused heavy losses to the lumber industry, is being avoided by treating the wood with a chemical solution. This preparation comes in powder form, and dissolved in water, produces a solution in which the rough lumber is dipped. While it will not remove the stain it already formed, the fluid acts as a preservative. The liquid is colorless and will not mar the wood when it is dressed and cut into smalle: sizes. Applied by brush to the exposed surfaces of lumber in completed struc tures, the solution reduces repair costs. Submarine’s Guns Guarded by Glass to Prevent Damage from Water Strong shields of glass over the range and deflection gauges on the submarine’s guns, protect the delicate parts from the action of the sea water when the boats submerge. Other parts exposed are mac of rust-proof bronze. The entire deck equipment is arranged so that the sub marine can descend on short notice with Hand Points to Glass Coverings That Protect Subma rine’s Guns from ater Damage out the need of removing the fittings or covering them with special protectors. 788 POPTIITL_LAR MEFCHANTCSG

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4 é / A POPULAR MECHANICS Y | a Wraxehiakesa VHA thie Exploring Launch Equipped to Make Ocean Currents and Their Influence on Weather Subjects of Scientific Study That Will Aid the Hydrographic Service in Perfecting Charts By S. R. WINTERS 4 ASURE the amount of heat stored greets you on the street toda th the ip in the oceans and you can tore exclamation, “Gee, what a cole rning! the conditions of the weather in 1927 lav be sharing the effects o un that t the latest scientific theory to ac none too generous \ th ( n for the freakish weather experi leat two vea is ed during the past few vears. For tance, the hvdro ce of lerbert J. Browne, of the Smithsonian e navy dep nt e ‘ titution, states that the weather for the trom riners t that the t three vears—1925 to 1927, inclusive temperature ( t te n ilready been determined by the heat the Gulf of Mexico were re in « ed in the ocean, which warmth was parison th ft é é tt ted from the sun during the years of uted to the fact that there eSst to 1924. That is to say, the waters of tl ount of the ocean are represented as a vast dut ng the | r ; ervoir for receiving and distributing tt te erature ¢ O it shed upon the earth by solar radia of Me O,a ding t ne Observations made under the direc- iblv account r the eno Dr. C. G. Abbot, also of the Smit] matt en ered [nstitution, indicate that the oceans (;ree! dd e aviat O ( tribute this heat to the earth in quan ice i! glit t ¢ irving from month to month and r of « ruthe e t vea he waters ot the oceans, te | ( eve act only as an intermediate res Mexico ni e Caribhe tat the storing of heat from the su Lieut. Ci George | { e t re oned, the full effect ot a ] arog viD1¢ Nce © ¢ oO! or solar radiation is not felt until this er a ts dist ; e VE tet it is, tlle person who of rain depend upon the ents, the

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788 POPULAR MECHANICS high regard for Dr. McEwen’s abilit comments Dr. W. J. Humphreys, of t weather bureau. “We want to see,” continues, “in most of these cases whe predictions are made, a basis for the pr: diction. Long-range forecasts are giv: out every year in all parts of the worl: and as a rule one is just a little bit worse than another, including those in the al- manacs. They are based on nothing what soever, and when you follow them out, year after year, they go absolutely to pieces. “We do want, however, scientific work such as McEwen is doing. He has ocean temperatures to a certain extent, but b no means as he or we would like them. No one has yet worked out the physical basis upon which a long-range forecast can be founded. Unless we have that basis there is little in such forecasts that intelligent men can place any faith in. As said be- fore, we have the highest regard for Dr McEwen. He is doing the right sort oi thing.” The weather bureau, however, is com- mitted to the expedition of the hydr 4 graphic office for the purpose of studyin P aethin en ani » the beds of the ocean. “There is need f ounting Gone. Shape of the Sea Floor. ~—s determining pretty accurately the surfac temperature of the water,” indicates D: temperatures and the salts of the surface Humphreys. “The present method of d: waters of this region and upon the winds. termining such temperatures is very crude Except for the winds, we know very little We would like to ascertain the temper: about these controlling things. Conse- ture of the water down to a tenth of quently, we cannot foretell what kind of degree. Small differences in temperatu: weather we are going to have next year. When we know more about the oceans, we can calcu- late the elements of the climate cycle, and we will then have a means of predicting weather con- ditions a year in advance with certainty, particularly the periods of rainfall and drought and their duration. This information will enable us to control our agricul- ture and to take full advantage of those climate and weather condi- tions upon which the productivity of the soil absolutely depends.” Dr. George F. McEwen has succeeded in a measure, accord- ing to reports, in predicting rain- fall in southern California from a study of the ocean temperatures of the preceding summer. How- ever, the weather bureau is dubi- ous about the possibility of long- range weather forecasting. “We are following George F. Mce- Ewen’s forecasts in California . Mees Palmlike Plumes of Marine Plants Caught by the Camera as They with great interest and we have a Swayed in the Motion of the Water Several Fathoms Down LKONn wnromawrnyr’yy «vy» arwmoeeorTroaterTraa

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e in the Indian ocean. t ice. POPULAR MECHANICS 789 perating Sonic Depth Finder Aboard the U. S. Hydrographic Surveying Vessel ‘“‘Niagara,’’ Whose Cruises Te uently are very effective in determin- igh pressure and low pressure. problem would be determining e temperatures to a high degree of here are some places that are re important in this respect than others e region between Washington and the *, in fact, from here at latitude thirtv degrees temperatures between here very important. w if there is a baro- (ne i¢ icy. mudas, OT! across e Atlantic data on he Bermuda e would like to k Ss are 1O c high-pressure ridge. There is, in tion to these high-pressure ridges, a gh-pressure peak at every place where of these ridges is crossed by a cold in current. We would like al a rvey of the out t of ice in the G nd Banks region and uld like to know whether that ice much more frequent in one year than | er. We would like to send people there and find out. Another thing we uld like to know about is the supply of One-half of the utarctic continent is merely a great sheet Ten, twenty, thirty, forty square les of ice will break off there and as a si amount of s floating ice varies in different years. attects the temperature and the distri tion of ; | Che ause ng that noat : ane ay singie berg. ihe atmospheric seems most nrecsscure pre ure logical as the c Expected to Reveal the Relation between Sea Currents and Weather another it langes in ocean temperature roes back to t is broken off of one differing from India is cl and that probably in quantity of Antarctic year cnanvges in the 1 ice tha “Another thing e WV ould Ke to Ow is the ditterence between the direction of wind and ocean drift. If the winds push the ocean surt n 1 certain i\ ind make the wate ft on in a manner de termined b r the 1 blows, the water must in turn react upon the atmos phere SO, also, must the l react upo the ls. \V\ e want definite determina tions of the direction and velocity of the wind with increase ot height. We want to de elop a piece of apparatus herel \ \ be ble to kt oO t! e rect mm at | © locit yf the wind t d ent heignts > an instrument can pe devised We find a curious thing commonly happens ere in Washingto1 d in most other place As you go up e velocit n creases at first L hie get toa ice ere the wind ts taster t n either ve or below. Why is it faster, and at this particular place I don't kno We want to know if that happens on the ocean 1n precis¢ the i e Wa if it i one law in one tituae nd anothe iW at a other ititt r W here ’ . sei ne cone iv ¢ \\ S ¢ W

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790 Reading the Log Which Registers the Ship’s Speed by a Rotator Dragged Alongside something about that, but we have never been there at the ‘borning’.” In recognition of the need for a thor- ough knowledge of the ocean and its effect upon weather conditions, the navy de- partment will begin an intensive study of the Gulf of Mexico next July. The expe- dition will study many subjects including the origin and habits of icebergs, the hot and cold currents, salt and gas in water, the plants and the animals that in- habit the sea, the winds and the waves, the fogs and the rains, radio com- munication and subma- rine cables, navigation and fisheries. In other words, the mysteries ot the deep will be explored and an inventory of the resources of the ocean taken; Sir John Murray having expressed the be- lief that the total or- ganic productivity of the earth's waters is probably considerably greater than the total productivity of its lands. That is to say, the vegetable and ani- mal resources of the oceans greatly exceed those of the land. Five- sevenths of the earth’s POPULAR MECHANICS of waters teems with living organis: k This expedition, under the direction Capt. F. B. Bassett and Lieut. Con George E. Brandt, of the hydrograp! office, will further contribute to the wea! of information now available regardin,s elé our oceans. For instance, the amount water in the oceans is 302,000,000 cul miles, or thirteen times the volume of the land above sea level. The avera height above the level of the sea of t various land areas is about forty-four on: hundredths of a mile; the average dep: of the sea is somewhat over two miles. The scientific explorers will not on take into account the resources of t beds of the ocean—the mud, the fish, a: other organisms—but the “how and wh of the Gulf Stream affecting the clima: of our entire eastern seaboard will be co: he sidered. After completing the operatio: in the Gulf of Mexico, the expedition explore the Caribbean regions and neig boring points of the north Atlantic, e tending south through the Panama ca: into the Pacific ocean to the Galapag islands. Subsequently, activities will | extended to the north Pacific and no: ct Atlantic oceans. “The climate of o1 Pacific coast depends directly on the oce to the west” declares Austin Clark, of t! Smithsonian Institution, “and responds once to the changes in that ocean.” 1 rainless summers of California, for i: stance, are due to such changes. surface is covered with water and this vast body Sound Screen “‘Blister’’ on the Bottom of Surveyin Signals under Water; Showing Cover Remov Vessel, for Sending and in Place arow caeawvTyTr AéAtftaéTrTlUPr Ore

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POPULAR MECHANICS 791 Rival of Glass Bounces Like Ball a Tye ( lution it can be applied ke varnish to pictures nd furniture, allowing re€ } er and Can Be Worked on Lathe \ithough it has every appearance of ss. a material invented in Vienna is stic and can be turned a lathe. When a piece the product is dropped a solid floor it is said bounce like a rubber Only great strains cause it to break, it cannot splinter. e material will take a sh similar to that of s and may be dyed or ined in the same way. ed as windows of ve- les, the substance may of value in preventing uries to passengers m shattered panes in e of wrecks. As a bstitute for glass in ys, travelers’ articles | roofs of hothouses, it uld reduce the per- ntage of breakage. It ilso said that in a thin quent washing with- it marring the surfaces, it is not readily affect- Caboose Plays Leapfrog in Wreck Landing on Top of Coal Car In a rear-end collision of two trains moving in the same direction, the caboose by acids or heat and Pinched between Engine and Cars Ahead, This Caboose Kept on Going after ld. In the fluid form, e substance may be used for mending ss and porcelain and for stiffening cloth. Weatherstrip Shaper Run by Motor Carves Molding on Window Sash For grooving weatherstrip after it has een placed on window frames, a motor- ven shaper may be adjusted to cut to ny dept h or rainst the casing. iv setting a Ith to make the ? ish fit tight readed ring on e cutter, the tool n be fixed to ike grooves at Zs ee are * “tout A ny distance from - edge of the strip, and a guide prevents implement from being deflected from ts path as it passes along the wood piece. e e device may be readily carried about needed, and power for its operation may drawn from any electric-light socket. Crash, Landing Safely on Loaded Coal Gondola of the freight ahead was catapulted over one gondola car and landed on top of an- other loaded with coal, but little the worse for its queer game of leapfrog. How the wooden caboose escaped being crushed between the locomotive of the rear train and the steel car ahead of it, is one of the mysteries that sometimes characterize such accidents. Two men le iped to satety just as the crash occurred Ventilators Used as Water Intakes Help Replenish Steamer Arriving at a wharfless port of one of the remote Aleutian islands, a steamer’s crew was sent ashore with two dories to get water from a small stream to replenish the ship’s tanks. When the small boats returned and were drawn alongside, the problem of emptying them, for a time, proved perplexing. It was finally solved by hoisting the dories and allowing the water to run out and into the tanks through the ship's ventilators.

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~~ io) Ca) POPULAR Chinese Sailors Make Costumes to Put on Queer Play Chinese sailors quartered in New York, after rescue from aboard a burning ship staged one of their native plays for which they designed and made all the grotesque costumes for the actors. From mate- rial of various kinds Grotesque Costume Designed by Chinese Sailors as Part of Properties They Used in a Native Play available, they formed weird - looking masks, imitation dragons, and other fan- tastic garbs, some large enough to require two players to manipulate them. Several of the false heads were supposed to repre- sent mythical monsters, and to add a touch of realism to the masks, movable jaws were attached so they could be worked by the player. Dragons’ bodies were made from cloth and set in motion by a man within. Imitation Porcelain and Marble Are Made from Feldspar From an output of feldspar valued at $43,153 in 1914, the mining of that mineral in North Carolina, where one-third of this country’s supply is produced, has devel- oped into an industry turning out a vol- MECHANICS ume estimated to be worth more tha $360,000 a year. Although the gathering of the material in that state did not begi: until 1911, the growing demand for imit tions of valuable stone has resulted in great extensions to th: workings. Used as both a base and glaze in th manufacture of pottery, =) chinaware, porcelain, and enameled brick and tile, feldspar is also the source > of the glistening materia © like marble and onyx seen as table tops, coun ter panels and soda four tains. Widespread em ployment of artistic ston work in interior decora tions has also caused heavy drains on deposit of marble and simila: naturally veined rock, 1 with the manufacture o , feldspar into almost per => iect imitations of these 4 materials the heavy ce mand for the natural a: ticles has been reduce Feldspar abounds in mat sections of the count: and is easily mined. War on Ants to Help Farmers of Tropics In an effort to comb the ravages of ants intropi cal regions, scientists 0! the bureau of agriculture are studying various pre| arations for the exterm nation of the pests. The white ants, whi travel in great armies, exist on wood an heavy roots and devour fence posts, hou pinning and even totally destroy sma buildings. Not only are structures at tacked, but cultivated vegetation by t! acre is consumed by the cutleaf or un brella ants. These insects often clean ou an entire garden in a night, leavi: nothing but the bare stalks of the plant In Colombia, where great colonies of the ants are found, they build large, con shaped mounds of a white claylike su! stance, which in many cases rise to height of twenty feet and at a distan look like Indian tepees. Once started on building, or piece of furniture, it is sa the wood-eating species cannot be stopp« by any method now known until the ma- terial is completely destroyed.

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POPULAR MECHANICS Radio Fog Signals So Successful That Service Is Extended at the value of radio as an aid to ration, especially as a _ protection st fog, the greatest of all dangers to ing, has been further demonstrated ¢ the past year and its use extended, ported by the lighthouse service. -e fog-signal stations and three light- have been equipped with wireless ning apparatus. Additions to these eing planned, and an increasing num- { vessels are being fitted with radio isses to take advantage of the safe- ds. The total number of aids main- | by the lighthouse service is now ‘8. This is an increase of 395 for the and includes 120 automatic lights of h forty-eight were installed to replace ded beacons at old stations. Automobiles Built in Queer Shapes to Save Weight and Space ilies of automobiles are being built jantastic designs to accommodate de- pments of machinery parts and to give cars artistic lines. One such model bited in Berlin consists of a sedan on ich all corners have been eliminated lucing a flat appearance when seen m a short distance. It is claimed this e is suitable for advertising purposes ce a great amount of space is provided signs and painted inscriptions. An- er light-weight vehicle has been con- icted with an enormous hood which ises the car to resemble a whale. Only ree wheels are provided, a single one ng under the forward part of the ma- ne. Steering is done in the usual way. Whale-Shaped Automobile of Light Weight Which Is Equipped with Ouly e¢ Wheels 793 Motorcycle Fire Engine in Action during Test It Also Carries Two Chemical Tanks Motorcycles Fitted to Fight Fires for Protection of Forests Promise of more effective protection of forests from fires is seen in a motorcycle outfit that carries a strong pump, hose, two chemical tanks, shovels, spades and axes stowed in a sidecar. Since these vehicles are capable of great speed and can traverse rough territory, they are able to reach spots inaccessible to other equipment. An extra man cn be carried on a seat behind the rider, and there is a sufficient length of hose for reach- ing streams or other sources of water supply. These outfits are said to have given satisfactory results in actual forest- fire tests in California and are useful also on the farm. @ The American flag that inspired Francis Scott Key to write “The Star- Spangled Banner,” is in the Smithsonian In stitution at Washington.

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4A1rwnoenorroé«taarTwyT ma y> 4A Dry DITT

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POPULAR MECHANICS 795 6 ’ iy ’ ‘ F 3 3 : ; al ae ee teal f » awe 3 Akron Plant to Build One Super-Airship and British Government : Two Five Million Cubic Foot Craft URRED on by the success Shenandoah,” “Daughter rs,” in her 9,000-mile flight of the of the around ee sides of the United States and back, | the journey of the “Los Angeles” m Germany to the United States, both erica and England are preparing to ld lighter-than-air ships which will be ‘e as large as the present navy craft. \irship building—before the w ar prin- ly a German industry—appears to be ling into its own. The treaty les, which forbade further of Ver- German nstruction with the exception of the os Angeles,” built as a war reparation, driven the Zeppelin constructors to er lands. An American company, vned jointly by the German Zeppelin terests and an Akron, Ohio, rubber man- icturer, are preparing to build c airships at Akron. ommer- [he English building program embodies eral novel features. Zeppelin con- ruction and use have been at a standstill the British Isles for four years—since e ill-fated “R-38,” built on order for the fell apart mid-air, causing the death of her entire The “R-34,” S. navy to be the “ZR-2,” glish and American crew. the old ship which was first to fly to America, has been lying idle and partly dismantled in her hangar ever since. With construction halted in England and Ger- many, and the United States the only builder, advancement in Zeppelin types practically stopped. The “Shenandoah,” built at Lakehurst, was modeled after the plans of a Zeppelin which fell in the American area in France during the war. Except for being larger, she is in no wise much different from any of the war-time German ships. The “ZR-3,” now the “Los Angeles,” is the same type of Zeppelin, with the addition of passenger accommo- dations. She is the biggest practical air- ship ever built, but her gas capacity is a quarter of a million feet less than the ill- fated “R-38” The new British ships, however, arid the commercial craft being planned at Akron, will present several new developments. The Akron plans have not reached the stage of publicity, but the English de- signers have announced their program. To begin with, the two British ships will each have a capacity of 5,000,000 cubic feet of gas—twice the the two American navy craft. each be size of They will

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POPULAR MECHANICS hie Pee tom ieee MOORING THE R-101" MOORING ROPE DROPPED FROM SHIP "SHIP BEING WAULED IN POPPI TAR NIFCHANTCS LOUNGE? ONTROL

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POPULAR MECHANICS 797 Lae ' TWO POWER CARS ABREAST. - ae 5 Pi Dy INSULATIN DOTTED LINE SHOWS | a ee ee LAYER OF INERT. | HOW ROYAL AIR- 3 aa NON-EXPLOSIVE] CRAFT HANGAR AT CARDINGTON, ENGLAND, IS BEING ENLARGED To . mt HOUSE THE NEW a SUPER-ZEPPELIN ——— -- . e Illustrated London News

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798 POPULAR MECHANICS Several Airplanes Can Be Carried beneath Cabin of New British Airships and Detached or Hooked On at Will While in Flight, after Manner Developed by American Flyers engined by seven motors, as compared to the American five, and, most radical de- velopment of all, the engines will burn kerosene instead of gasoline. Each mo- tor will develop 600 horsepower, and will have eight cylinders. No magnetos will be used. The substitution of kerosene for the more dangerous gasoline is hailed in I-ngland as the greatest advance of all. In every case in which a Zeppelin has been destroyed by fire, investigation showed that it was the gasoline which caught first, S00 POPULAR Copyright, Illustrated London N and then set fire to the inflammable drogen gas. The American navy ships, being filled with helium, of course, are not subje to the same fire danger. The United States has a monopoly on helium gas, but the British are planning to make thei hydrogen ships sate, and at the same ti! give a greater lifting capacity than heliu: by the novel idea of surrounding ea hydrogen gas bag by an outer envelo| containing either helium or some oth MECHANICS

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4 POPULAR t gas. The English ships will have a ework of stainless steel, instead of luraluminum alloy used in the Ameri- ca craft, and will weigh about 150 tons, ¢ a “disposable” load, for passengers cargo, of forty-four tons. They are be- pecially designed to operate at a profit e London-India service, with accom- itions for 200 passengers in peace or 100 soldiers and full equipment ir time. Provision is also made for MECHANICS 799 always carried in a car suspended near the nose of the ship, has been moved back, well amidships, and prolonged to many times the size of the cars on the American ships. The cabins will really be two-story houses, with the dining saloon, galley, lounge, smoking room, wireless shack and control cabin on the lower floor, with windows through which the passengers may watch the passing scen- ery, and the sleeping berths above, within the body of the ship. The English ships will be moored at 180-foot masts, equipped with electric passenger elevators. The ( erting them into hospital ships to port wounded soldiers quickly to base hospitals. Their great size, with twice the gas city of the rican navy will not e them pro- rtionately ver. In fact they will be but 72) feet long, ompared to t 656 feet of “Los Ange- es.” and some 75 feet of the enandoah.” e increased gas capacity ll be ac- unted for, wever, by their diameter 130 feet dships, as mpared to e ninety feet x inches of e “Los An- geles,” and the still slimmer Shenandoah.” he greatly in- reased girth, vever, is not ‘pected to give much more head re- tance, since the streamlines are still well roportioned. n the air the t-nglishairships ll present an usual ap- pearance, since e pilot cabin nd passenger commoda- tions, hitherto success of the American mooring masts both on land and on the airship tender “Patoka,” at sea, has assured their use, despite the fact the Ger- mans never approved of them, and in- sisted on using hangars on all occa- sions. That an airship the size of the two American navy craft could be operated at a profit in commercial business is the contention of experts, Giant Pipes to Pump Gasoline, Oil and Water Aboard, and the Swaying Basket Elevator for the Human Freight Are Features of the American Mooring Masts and they point to the profitable busi- ness of the “Bodensee” in Germany, a ship much smaller than either of those now at Lakehurst. This claim is strengthened by the fact that the big new ships now being started, can earn a far greater proportionate profit, since the weight of a rigid airship increases approximately as the square of the linear dimensions, while the lifting power increases as the cube of those dimensions. POPULAR MECHANICS 801

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S00 POPULAR Slide Rule Holder with Rubber Pads Permits Use of Other Hand The value of the slide rule as a time- saver in computing ts said to be practically Using Slide Rule and Holder with Only One Hand Leaves Other Free for Writing doubled by a holder for the instrument that may be placed in any convenient posi- tion on the desk and has rubber pads on the bottom to keep it from slipping. With this device, one hand is left free for writ- ing. Coil springs hold the rule.in place. More Men than Women Are Left-Handed Men lead women in the tendency to- ward left-handedness, according to Prof. June E. Downey, of the University of Wyoming, who recently completed exam- ination of 400 men and women. She found that those who could use either hand with equal ease were gener- ally of superior intelli- gence. It was also dis- covered that, while fewer women were left-handed, there were also f ewer women who were strong ly right-handed; that people who placethe left thumb over the right when folding the hands are inclined to- ward left - handedness, and that, for many indi- viduals, the distinction between left and right is not nearly so well devel- oped as that between up and down. In fact, many people have to rely upon some special mark to dif- ferentiate their hands. MECHANICS Rooting of Football Fans Measured in Effect on Grandstands Added strains on the framework of a stadium caused by enthusiastic move- ments of the crowd were measured by the bureau of standards during a football game, in an effort to determine the best type of construction for the safety of such structures. When the audience was still, the strain on the steel frame showed an increase of about 1,000 pounds above no: mal conditions, but when the fans ex pressed their feelings by stamping or simi lar rapid motions an addition of 300 pounds was noted. The worst condition from the point of safety occurs when the crowd indulges in rhythmic stamping, which causes a strain exceeding the no: mal figure by 150 per cent. By means of these tests, it is expected valuable data may be gathered as a guide for future buildings devoted to large public gather ings, in the interest of safety. Mattress Used as Life Preserver Is Worn Like Sleeping Bag One of the crew of a Pacific liner has invented a combination mattress and life preserver for service in case of shipwrec! It is filled with a vegetable floss, chem cally treated to make it waterproof, and is worn like a sleeping bag when it is to be used as a buoy. The arms are left free and ample leg movements are possible while wearing the device, so that a perso can propel himself while lying flat a: floating on the water. It is tied on with a few straps that can be adjusted quickl) Bundled in Life- Preserver M a'* tress, Sail Floats Safe and Dry Till Rescued POPULAR MECHANICS

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POPULAR MECHANICS wa ae \ §) 801 Cutting Out Material for Inlay Work, Smoothing Edges, Finishing Cabinets and Sharpening Tools with Emery Attachment, All Done Easily with Electric Shaper Operated with One Hand Electric Shaping Tool Fits Hand and Saves Woodworker’s Time Run by electric current supplied from wall socket and easily guided by hand, shaping and carving tool for wood- orkers has a wide variety of uses and per- its doing many tasks that otherwise ould have to be assigned to more elab- rate machinery. It consists of a one- ghth horsepower motor inclosed in a ooling chamber that does not get too t for the touch. On the revolving huck, a number of different kinds of cut- ting and carving attachments may be fixed, or a small emery wheel may be ad- usted for sharpening. Finishing and lecorating radio cabinets, making samples of furniture and applying inlay, line and two-tone work are but a few of the tasks the tool will accomplish. It weighs but i few pounds and requires little current. @ We want all our readers to write us ireely and often whenever they wish ad- litional information on articles published in this magazine. Address Bureau of In- iormation, Popular Mechanics, Chicago. Flexible-Disk Auto-Truck Wheels Ease Bumps from Solid Tires Disk wheels for auto trucks, that are said to permit the use of solid tires with- out sacrifice of comfort and afford saving through greatly increased mileage and less wear on the car, are now on the market. An outer felloe rests upon a series of eight coiled springs bolted to it and to the inner disk, thus making the wheel flexible and taking up shocks before they can reach the axle. At the ends of each spring is a fixed ball seat, ad- justed in such a way that it responds both to uneven surfaces and to variations in the load. Test runs are reported to have shown that more than 50,000 miles can be obtained from a single pair of solid tires with this wheel, and that riding is as comfortable as with pneumatics. POPULAR MECHANICS 803

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802 Doll with Interchangeable Heads Is Whole ‘“‘Family”’ in One Dolls with heads that are screwed on or off and have costumes to match the dif- Unscrew the Head, Put on Another, Another Doll to Play With ferent faces, have been devised to-add to children’s amusement and to develop their imagination and creative instinct. From three to twelve heads, and as many dresses representing a number of characters, can be obtained with each body. The dolls talk and walk, are unbreakable, and legs, arms and heads are made of a durable sub- stance that is said to be proof against peeling or cracking. Million Articles Lost Every Year on Railroad Trains The number of forgotten articles left lving around railroad stations and intrains has become so great that special depart- ments have been established for their care and disposal. The variety includes almost everything from books to live animals. One eastern system collected more than 10,000 pieces of lost property in a year from their suburban trains. Of these 4,115 were returned to the owners. Inthe collection were 1,200 umbrellas, 300 watches, 400 bunches of keys, and 600 rub- ber shoes. A total of $1,486.59 was found, of which $500 was the largest single amount. At the end of a twelve-month period all unclaimed matter is sold at auc- tion. Among such a lot were an artificial arm, a cork leg, and a glass eye. Sf) 4 POPULAR Change the Dress, and You Have POPULAR MECHANICS Movements of the Body Measured in Units of Heat Ten per cent more energy is consume by the average person in standing up tha: is required when lyin down or sitting in a chai: according to Dr. F. G Benedict, of the Car negie institute, wl measures heat units re quired for various m tions of the body. Thi experiments showed that each change of positio: caused a correspondi: rise in the energy output of the body. Some people, the scientist said require as much as forty per cent more energy t stand than to lie. li a person in a reclining po sition raises the hand t the head and back, as in a military salute, one suc! movement each minut raises the heat out put about one per ce: Working to the limit « endurance, a man may increase his noi mal heat output 1,000 per cent. Auto Ambulance for Cats and Dogs Has Separate Cages for Patients Treatment of sick and injured cats and dogs at an animal hospital in England aided by a special ambulance that speed to the owners’ homes and carries the pet to the operating or examining rooms whe: occasion demands. The vehicle is an ord nary small motor delivery truck with t! rear fitted up in individual compartment Copyright Underwood & Underw Removing Pets from Ambulance Compartments; Oute Doors Protect Them from Cold and Dust with separate doors and two larger outsid« doors that cover the tiers of cages. MECHANICS

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POPULAR MECHANICS 803 Carving Furniture by Machinery Multiple-Spindle Cutters Duplicate Finest Hand Work- manship on a Wholesale Scale REVIVAL of carved furniture has resulted from reduced costs follow- ng the invention and installation of auto- atic machinery to make decorative tterns, period designs and special com- nations, many of which rival in finish nd intricacy those made by hand. [hese carvings are not wholly machine oducts for they are copied from a pat- ‘n that has been chiseled by hand, and ch bit of decorative woodwork goes rough at least two hand-finishing proc- under skilled workmen before it ives the shop. The machine's great con- bution is in doing the bulk of the cut- ng and scraping, leaving the human irvers, who command from $1 an hour upward, to devote their entire time to the ore delicate operations. \ modern furniture factory hums to e vibrations of what are called multiple- indle cutters that duplicate simulta- eously, in from eight to twenty-four eces, every twist and curve that a work- en's chisel has left in a wooden pattern. Vith their daily output of upward of 600 against the four or five possible th hand tools, the saving is apparent. esses eces POPULAR MECHANICS 80 The twenty-four cutter, the latest de- velopment in furniture-carving machinery, consists mainly of a stationary table with a row of separate vises for holding and adjusting to any angle the wooden pieces that are to be carved. Suspended from the ceiling is a swinging frame called the “head.” It is counterbalanced so that it can be moved about easily and holds a row of twenty-four bits, each fixed in a chuck These tools are grouped in sections of six each, and each section is run by a sepa rate electric motor. ‘The bits are set ver- tically and are whirled by belt drive at the rate of 6,000 to 10,000 revolutions pet minute. The original pattern, made by a hand carver, is placed in the center of the table in a vise similar to that which holds the blanks. Just above it, is a short, blunt bar, attached to the swinging head like one of the bits. The operator grasps this and holds it against the pattern. As he moves it along the lines of the de sign, the entire head with its twenty-four whirling bits is moved and every curve and depression in the original is dupli cated in each of the twentv-tour piece swinging frame is so caretully hal The or

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S04 POPULAR MECHANICS ‘ ——EE = =~ as Pattern for Machines from Hand Carver Preparing Piece | Artist's Drawing Sandpapering Edge after Carving iews of Multiple- Spindle Carver with Op- erator Guiding Battery f Bits; as He Follows Pattern Block in Cen- er, the Entire Swinging Head of the Machine Moves and the Design Is Traced on Eighteen More Blocks Simul- taneously Y 506 POPULAR MECHANICS condition, else the pieces will be spoiled. pieces. When mahogany or other exne:

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POPULAR Alining the Pattern at Joints on Chair After Pieces Have Been Put Together, the Final Process in Hand-Carving Department MECHANICS 805 = ae need that deep cuts and light scrapings n be made at will. The bits are set al- ernately to cut in a right and left direc- for if all were rotated in the same ay, the pull would drag the entire as- embly out of the operator’s hands and uin the work. Three principal kinds of bits are used. The first, known as a “rougher,” is a double-bladed cutter that removes the bulk of the wood and traces the principal outlines of the design. Next comes the ‘smoother,” a spoon or pod-shaped bit hat takes off the rough edges left by the first tool, and last the “finisher,” a sharp round instrument that brings out the re- lief and does as much of the finer work as can be done by a machine. All three tools are employed before the pieces are re- moved from the vises, as it would be im- possible to reset them in the identical posi- tion they first occupied. When the articles have received their machine carving, they go to the hand workers who prepare them for assembly. Rough edges are chiseled off, the relief is still further developed and sandpaper is used to wear down the marks left by the bits. There is but little machine carving today that does not receive extensive reatment from these workers. One more ind operation is needed before the piece eaves the department. When legs, arms nd other parts have been assembled in e cabinet section, the design and figures POPULAR MECHANICS of the different members are not in true alinement at the joints. Hand carvers therefore must true them up by an opera- tion known as “trimming.” When this is completed, the piece is finished so far as the carving department of the factory is concerned. Many small articles can be carved without placing them in a multiple ma- chine, and for this purpose the spindle cutter has been designed. It is like an emery wheel with a rapidly moving little steel bit in place of the grinder. The work is held in the hands, and the pat- tern is cut entirely without the aid of design marks by simply holding the wood under the bit and passing it in the re- quired direction. These pieces can be turned out rapidly and with great accuracy. One of the most ingenious machines in the furniture-carving department is a cut- ter that will make the exact reverse of the pattern. As the operator follows the lines of the original, say the left leg of a chair, for instance, a bit, set in a swinging arm at the side, reproduces the same de- sign for the right leg, cutting it into the piece which has been clamped alongside the pattern. This one machine has saved furniture factories thousands of dollars and accounts for the perfect symmetry of the right and left members on various articles. Hundreds of bits are required by the carvers and they must be kept in pertect S07

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306 POPU condition, else the pieces will be spoiled. Sharpening them and inspecting them is one of the most important jobs in the de- partment. They must be fixed at exactly the same height in the machines and care is taken that each block of wood is set level. ‘Geeninens of the cutters are said to acquire a subconscious skill which en- ables them to guide the spinning bits as delicately as they would a hand chisel. Their work is important, mistake in mean as ) } I fora slip ora may spoiled follow ing the many as pattern twenty-tour LAR MECHANICS pieces. When mahogany or other expe sive woods are used, this loss may rea a considerable sum. Designing the pattern is done in a: other department where artists in wo originate novel combinations of scro and decorations and keep constant watc! on the trend of public taste in matters « furniture. Their job has become increa ingly difficult of late years, they say, f something new is in constant demand an there is a larger market for the bett: qualities of patterns. Below, Completing Pattern from Which Dozens of Dupli- cates Will Be Made in Fraction of Time Spent on Original Left, Operator Removing Finished Work from Multiple Carver; He Brushes the Fine Chips from the Depressions and Carefully Inspects Each Piece Before It Is Sent to the Finishers, Then Inserts An other Set of Blank Blocks, Turns an Electric Switch, and the Bits Buzz as They Bore into the Wood; Beiow, at Right, a Worker Is Us- ing the Single-Spindle Carver on a Flat Piece; Work of This Sort Car Be Done Faster and More Cheaply with This Type of Carver as No | Adjustments in Racks Are Neces- sary and the Designs Generally Ar Simple; Different Kinds of Bits Are Inserted Quickly in the Shaft | When Needed 808 POPULAR MECHANICS Revolving Stands for Mail Boxes Air Waves Like Those af Orcroean

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POPULAR MECHANICS Paper-Lined Sacks to Ship Wool Save Sheep Growers Money By the simple expedient of putting paper ng inside the jute-fiber sacks used for pping wool, sheep growers in Aus- lia are reported to effect an increase in ue of approximately $3,000,000 of th- nual clip. The paper keeps the sack fi from becoming mixed in the wool. rmerly, the product had to be cleaned remove the scraps before it could be t to the spinning mills and the expense he process was charged to the growers. e paper is of a thin, tissuelike quality | is placed in position after the sacks in the presses ready to receive the ece. Its use is said to be the invention young girl. Color Photos at One Exposure \ German is reported to have invented rocess for taking natural color photo- phs at one exposure. Three negatives, th red, yellow and blue filters and an rangement of mirrors for reflecting the used at the same time. In nting, the negatives, with their respec- e filters in front, are projected on a spe- paper, producing a naturally colored cture resembling a good three-color int. This saves taking three dif- rent exposures, and the method is said be equally successful on portraits, in- rior views or landscapes. age, are Screws Driven into Metal like Nails to Save Time and Labor Screws for all sorts of fastening work in etal which can be driven in like nails iter a hole has been drilled, save the cost tapping and are said to remain fast almost indefi- tely. They are suited for permanent assemblies on achinery, motors, fans, acuum cleaners, radio ap- aratus and many _ other purposes, displac- ng ordinary es- ‘utcheon pins, ex- pansion nails and ivets. Threads on he screws cut and vist into the metal : they are driven The They are fur- ished in plain steel brass-plated and are made in a number different sizes. POPULAR MECHANICS Screw Is Started Like Turns as It Goes Down 807 Portable Motor Concrete Finisher Cleans Stone and Removes Paint With a compact, motor-driven concrete surtacer and finisher that the workman Smoothing Rough Concrete with Finisher “Run by Motor with Cord Attachment at Worker's Waist carries by means of broad shoulder straps, form marks and other irregularities are quickly removed or special finishes applied to cement. The entire apparatus weighs only thirty-two pounds and the tool itself ten pounds. It operates on direct or alter- nating current and has a capacity of from thirty-five to 100 square feet of surface an hour, depending upon the kind of work that is being done. The concrete is smoothed by means of a set of sixteen steel cutter wheels that revolve rapidly within a disk held in the hand. A grind ing attachment is provided for working in coatings of ce- ment and sand after the roughness been removed. Other appliances, such as a cushion hammer for drill- ing, sander plates for surfacing small floor areas, steel brushes that clean stone and remove paint and rust from metal, and an attachment for sawing can be used with the outfit. Working parts are ball-bearing and are lubricated through a single grease cup. Operating cost, including cur rent, it is said, will not average over two dollars a day. has a Nail and 809 NN Oe

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808 POPULAR MECHANICS Revolving Stands for Mail Boxes Save Postmen’s Time Strongly anchored to a concrete base, z revolving metal rack that will hold from one to a dozen mail boxes has been de- Taking Mail from Box on Revolving Rack That Turns on a Strong Concrete Base vised to save postmen time on rural routes. While seated in his delivery car, he can put mail into any one of the boxes simply by turning the frame. Inner braces on the sides of the rack form sup- ports for the various letter holders and furnish convenient strips to which they may be riveted or otherwise attached. Paving the World’s Streets The lake of asphalt in Trinidad has fallen only fifteen feet since its discovery by early explorers, despite the fact that approximately 4,000,000 tons of road-mak- ing material have been removed: It is estimated that 10,000,000 tons of the mix- ture have been churned into asphalt by gases during the ages in Pitch Lake, which is known as Devil’s Caldron among the natives. To transport the material, rails mounted on ties have been extended over the surface, and cars are run out to the diggers who never move the scene of op- erations, as each morning finds the holes leit by the previous day’s activity filled up. About every three days, the pitch covers the railway, which slowly sinks into the soft material and must be raised and re- laid. By means of this track, 100,000 tons of asphalt are withdrawn from the lake each vear. The entire deposit covers an area of about 110 acres, but its depth has never been measured. 810 POPULAR Air Waves Like Those of Ocean But Hundreds of Times Larger Just as the sea is constantly disturbe by crashing breakers, so the air is filled with waves, like those of the ocean, an caused, scientists declare, by current blowing across quiet areas. These waves, it is said, have crests and troug and sometimes have dimensions 2,5 times greater than those of the sea, ex tending ten and twelve miles above thx surface of the earth. Their movement are believed to partly explain the sudde: gusts which occur in storms, Double-Faced Pocket Calculator Adds, Subtracts and Divides Compactly constructed as a flat pad that will fit the pocket, a timesaving calculat ing device that adds, subtracts and divide- has been placed on the market. One sid is used for adding, the reverse for t! other operations. Results are shown in row of holes at the top of the digit co umns, and the mechanism is moved by i: serting a pointed stylus in the prope apertures on the card. The calculator | said to be absolutely accurate, does no! easily get out of order, and besides wor! ing problems, registers errors the operat: Addition and Subtraction-Division Sides of Pocket Ca’- culator; Results Appear in Top Row of Holes may make in moving the figures by show ing red signals in the result column. MECHANICS ] graphic impressions

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POPULAR MECHANICS smitter That Over One Hun- i Typed Words a Minute 809 Letters Sent through Space by Radio Exact Duplicates of Hand and Typewritten Missives Are Transmitted at Rate of Hundred Words a Minute [)' IN’T write; send a telegram,” the slogan of a telegraph company, may modified in the future to read, “Don’t te or telegraph; send your letters by lio.” That is, letters written by means typewriter or pen and ink may be sent received through space without in- ing wires. This method of exchang- business communications is described the radio-photo letter.” Francis Jenkins, inventor of a radio tion-picture projecting machine, has ised an apparatus for the transmis- and reception of written messages ut resorting to the conventional way communicating the written word, ely, the telegraph code. Instead of ling communications by means of dots, hes, and spaces, common to telegraphy radio telegraphy, photographic impres- ns of letters are sent and received, uthful to the manner in which they are itten. lhe radio-photo letter is one of the ree lines of development in which Mr. lated and the principles underlying their operations are so nearly identical that only slight modifications of instruments and equipment are necessary. However, the transmission and reception of both pho- tographs and letters by radio are accor plished facts, while radio vision, or the ability to visualize distant objects and look on distant scenes, has not advanced be yond a laboratory experiment. The principle of sending and receiving business letters by radio is not new; the novelty of the thing is in its applicati That is, instead of a business man cot municating by means of telephone telegraph as formerly, he has a letter type written and transmitted at a 186,300 miles a second. Not message delivered with the speed of light but the communication thus dispatched retains the authentic character of an aut graphed letter. For instance, handwriting or signatures to typewritten letters are faithfully transmitted and received; there is no doubt as to the authenticity of a speed api Oo! \ ! I kins is primarily concerned; the other communication thus transmitted. Radio » being photographs by radio and radio photo ‘letters are sent at a rate of 100 ion. The three projects are closely re- words per niinute, although it is antici- POPULAR MECHANICS 811 Oak Common I[ichtnine Tarocet Inklece Printing Preece Turne Onr

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810 POPULAR MECHANICS COL.PAUL HENDERSON, ASSISTANT POSTMASTER GENERAL, WASHINGTON, D.C. MY DEAR COL. HENDERSON: ~ THE SPEED OF RADIO. THE EAR OWLY. GARD DELIVERY OF THE ORIGINALS BY MAIL=PLANE, MEANS OF COMMUNICATION, THIS tS AN EXAMPLE OF OUR NEW RADIO- PHOTO LETTER, A METHOD OF TRANSMITTING MESSAGES BY RADIO IN= STEAD OF BY STEAMSHIP, WASHINGTON TO PANAMA IN FIVE MINUTES, 1T HAS THE AUTHENTIC CHARACTER OF AN AUTOGRAPHED LETTER, AND 1T §S THE BEGINNING OF A RADIO SERVICE TO THE EYE, WHERE HERETOFORE RADIO HAS BEEN AN ADDRESS TO WiLL THE TIME SOON COME WHEN THE POST OFFICE DEPARTMENT WILL DELIVER BY RADIO PHOTOGRAPHIC COPIES OF ouR BUSINESS LETTERS AT THE SPEED OF LIGHT RATHER THAN THE LA&G- CHANGE OF INTELLIGENCE WOULD WONDERFULLY SPEED UP INDUSTRY BECAUSE, LIKE AN ARMY, INDUSTRY CAN GO WO FASTER THAN ITS graphic impressions would constitute an autographed order and would command obedi- ence thereto. Mr. Jenkins, in the transmission of pictures and letters by radio, does not require a_ special band of wave lengths, as now allocated to other radio services. “I nci- dentally,” he explains, “may I suggest that there are possibilities in radio service in the almost unlimited frequencies above audibility, in which speed transmission is SUCH AN EX= Sample of Letter as Sent by Radio with Original Signature Exactly Repro- duced, an Advantage over Dots and Dashes pated that the speed may be increased t6 1,000 words a minute. “Radio messages in facsimile,” stated Mr. Jenkins in an interview, “of hand- writing, signature, and _ explanatory sketches not only can be sent in speed competition with the dot-and-dash tele- graph, but they have unusual tactical value to the army and navy, for this is the only method of radio communication which may carry its own authentification by the addition of the autographic signa- ture of the sender.” The mechanical means of transmitting and receiving business letters by radio is that of the so-called cylinder method. The operation depends upon the rotation of two cylinders. The apparatus is not new. In fact, Mr. Jenkins picturesquely claims that the mechanical parts were re- covered from his “museum” and that they are at least fifteen years old. Modern technique has been applied to this old ma- chinery, and as a result a combination de- vice for both sending and receiving let- ters by radio has been produced and placed for commercial use. The cylinder meth- od also has been employed by the Amer- ican Telephone and Telegraph com- pany for the transmission of pictures by wire and radio, one unit being used for sending and another for receiving. Business letters by radio, according to Mr. Jenkins, would speed up commerce, and yet such communications would be none the less authentic and_ binding. These same letters, because of their pho- tographic accuracy and autographic au- thenticity, would be admissible as evidence in court. In time of war, these photo- $12 POPULAR Prize Cabbage at Fat-Stock Show greatly accelerated by the tolerance of eyesight, not possible in an appeal to the ear? Witness the motion-picture screen upon which a pic- ture is taken off and put back again forty- eight times per second without annoyance to the eye; while the slightest error in a note in the orchestra is detected at once and grates harshly on the ear. “We don’t particularly need any special frequency band, nor does the use of our devices in any particular way interfere with other stations. Radio engineers have been working in the very limited audio- frequency band, a range of relatively few cycles, somewhat comparable to the old long-wave limitation, whereas the work- able range where light instead of sound is employed goes up to millions of cycles. | confidently predict that the next great de- velopment will be in this area. Inciden- tally, there is this advantage also, in the use of light instead of sound, the bite oi the ‘static’ is not fatal.” World’s Climate Has Not Changed That the world’s climate has remained practically the same for centuries and wil! not change noticeably for ages to come, is the opinion of James H. Carr, official fore- caster of the United States weather bu- reau in New York. As proof of his asser- tion, he cites the redwood trees in Cati- fornia some of which are 4,000 years old. They could not have attained their great age had climatic conditions altered to any great extent, he believes. There are weather changes over pericds of years and variations in the climate but, in general, it is regarded as a steady procedure with no more real differences than exist in oiler natural phenomena, MECHANICS produce the desired result. Old wolves

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POPULAR MECHANICS 811 Oak Common Lightning Target Inkless Printing Press Turns Out Because of Deep Roots Complete Typewritten Letters tudies in western Europe are reported While printing imitation typewritten ive shown that the oak tree is more letters, an automatic press fills in each uently struck by lightning than other eties. This is believed due to the deep system of the oaks, and because they in loam and sandy earth—better con- Feeding _ Address tors of electricity than clay. Their Pts Lk t and starchy content constitute an Inkless Printing itional danger to them. Elm, ash, —— See ir and gum trees have also been Letters Ready for nd rather susceptible to damage, while Mailing chestnut, maple, cedar, alder and untain ash are less attractive to light- The department of agriculture has mmended that valuable trees be pro- d with rods. [Telephone Booth with Lattice Legs Affords Ample Ventilation City telephone booths. now being in- led in Gothenburg, Sweden, for street ice, have only the upper part inclosed, ing the lower portion open except for ttice screen on three sides. This is said ve adequate ventilation without inter- ng with the use of the instrument, and off noises that sometimes make it ult for talker and listener in ordinary sheet with the individual name and ad reet phones. The occupant stands on a dress to which the circular is to go. All ised platform above the pavement. of the type matter may be produced on an ordinary typesetting machine. After the body of the letter is locked on the form, the address “slugs” are deposited in a tray from where they are automatically fed in to contact with the printing ribbon, and are removed to a storage chute. No rol! ers, inking pads, or other similar attach ments are necessary on the machine Manned by two operators the press cat turn out 2,400 matched letters in an hour eliminating the labor of a number of tvy ists who would be necessary to fill in the sheets with addresses. Railway Bridge Planked for Autos Serves during Washout When floods swept away both road bridges over the Van Duzen river in Cali fornia, auto tratliic was spared a long delay by putting planks over a railway bridge hear by and using it as a crossing durin the emergency. Gates were placed at thx approaches and watchmen stationed to warn of trains. Semaphore signals were lenty. of Fresh Air Always Reaches This Telephone installed some distance back of the bridge Booth through Lattice Openings Below tor the guidance otf engineers. \o 2) + ee) POPULAR MECHANICS

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812 POPULAR MECHANICS Prize Cabbage at Fat-Stock Show produce the desired result. Old wolve Covers Platform of Scales seem to grow “wise to” the tactics of the hunters and avoid traps and poisone Judges at a fat-stock show in England baits no matter how carefully the lure had difficulty in weighing a huge cabbage are concealed or disguised, but mai young ones are killed by these method Naturally accustomed to run in packs, in dividual animals, growing bolder, travel alone. One such beast took heavy tol from cattle herds in Colorado for a long time until finally caught by an ingeniou trap set by a government hunter. Anothe: lone wolf slaughtered sheep and cattle to the value of $25,000 before poisoned bait ended its foraging. This animal was fol lowed nightly by a pack of coyotes, whic! fed generously on the remains of the car- casses left by the killer. Folding Tray Carried with One Hand Saves Labor and Breakage Much of the work and hazard of carry ing breakfast or tea dishes on an ordinary tray is eliminated with the use of a double section holder that lies flat on the table QV. & U and folds into an upper and lower sheli Its Broad Leaves Overflowing Platform Scales, This arrangement with a handle for easy lift ules Cantage Proves Siieuk to Weigh ing. One hand is left free for opening doors when this article is employed, it is so compact that it allows free passage through narrow places and there is little danger of the dishes slipping off. entered with the exhibits, as its leaves spread over the platform of the scales and rested on the floor. These vegetables, while comparatively low in food value, rank next to the potato in quantity con- sumption per year and more than seventy varieties are known and cultivated. Some species = - attain a height of ten feet and the stalks are used for canes. The common garden cabbage is more than ninety- seven per cent water. No Quarter Is Given in War on Wolves Wolves, in spite of the long fight waged against them by county, state and national govern- ments, are still a source of worry and loss to ranchers whose live stock they destroy or menace. For ten years the gov- ernment has sought their elimination. Bounties, ranging from $2 to $10 a piece, have been. of- fered for the scalps, but == even this has failed to Tray Set Flat as Table and Folded for Carrying with One Hand Time and Money-Saving Tools

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POPULAR MECHANICS ntal Ambulance at Country Schoolhouse, and In- View Showing Dentist at Work on a Patient Auto Equipped as Dentist’s Office Serves Country Towns \ dentist’s automobile ambulance has een put into service by the state board health to serve persons living in the lving sections of New Jersey. It is ted with a chair and a complete set of lements for almost all kinds of work the mouth. Wide windows afford bet- illumination than is to be found in he ordinary office. A dentist and attend- accompany the traveling clinic, visit- country schools where examinations re made of the children’s teeth. Lectures re also given to the crowds that usually vather as soon as the ambulance halts. Latest Air-Mail Plane Is Safer, Faster and Cuts Costs \larked reduction in carrying costs and reased speed for delivery of Uncle air mail are promised in a plane ubmitted to the post-of- tice department after having been flown 100,- 0 miles in test flights. it is said to be capable of bearing seven times the load now allotted to the crait, reducing cost of mail transportation from 2.63 per ton-mile to about thirty-five cents, ind can maintain a speed 130 miles an hour as vainst 100, the present average. These results are reported to be due chiefly to hanges made in the wing equipment. In ldition to the regular two broad ones, tour wings have been placed between iv 2) _ Ae) * FuRr AL OF ooh AYGIEN SY te el kw 1 them, two on each side and at an angle. They are said to function after the man ner of parachutes, permitting low speeds when landing, giving greater gliding dis- tances should the motor fail and prevent- ing nose dives and tail spins during flights. Bank Deposit Chutes in Outer Wall to Foil Safe Robbers For the convenience of firms that may have deposits to make after closing hours and to spare them the risk of keeping large sums in office safes overnight, a Texas bank has installed a system of steel chutes that extend through the outer wall and are reached from the street. Each customer is given a key to the chute he At First Sight, This Plane Looks like Others, but There Are Four Steadying ings between the Two Big Ones rents. The bag containing the day’s re ceipts, or other valuables, slides down a passage too small to admit a person into a steel compartment inside the bank build- ing and is duly recorded the next day. for Woman’s Workshop in Home

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Time and Money-Saving Tools \ By Thrusting This Corer Part Way into the Apple, the Center Is Removed, Forming a Cup for Sugar in Baking By Turning Top Crosspiece on This Opener, Can Itself Re- ee volves, and Top Is Yj Removed by Steel Wheel without Danger to Fingers For Homes without Plumbing, Folding Bathroom with Oil Water Heater and Decorative Screen, Inclosing It When Not in Use, Provides Comfort and Convenience Clamp for Lifting Stack of Hot Plates _ Will Not Release Them Until Laid Down Toaster Browns Both Sides at Once and Has Button for Lift- ing Slice Several Kitchen Tasks Are Done with Handy Little Tool at Right, Such as Durable Scraping Pans and Bread Boards with Hat for Broad Edge, Cutting Cakes and Cookies, House or Garden or Marking Pies and Fluting the Edges to ear Make the ules Stay In, with Little Wheel at Corner; It Can Be Hung on Nail through Hole at Side and Lasts Indefinitely RR ' ama lla aan” waa Anyone wishing further information on devices described in the editorial pages can Simple and 816 POPULAR MECHANICS

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for Woman’s Workshop in Home Left, Plant and Flower Label That Keeps ame from Weather in Transparent Top Beater with Handy Holder and Crimped Dasher for Fast Work Rocker Seat for the. Baby Is on Wide Disk Base So It Cannot Tip Over and Affords Healthful Exercise for Infant Learning to Walk By Turning Knob, Stamps, Bearing Words or Marks the Buyer May Select Are Moved into Place This Wrench Fits All Sizes of Tops, Won't Slip, Gives Powerful Leverage and Spares the Hands Left, Handy Sifter for Flour or Other Materials That Rests upon Dish or May yy Be Attached Permanently to Table; the Protecting Plate at Right Is a Double Air Chamber to Equalize the Heat, Keeping Liquids or Food from Boiling Over When Using a Gas Flame, or May Be Used as a Toaster or for Heating Flatiron y addressing Bureau oi Information, P ypular Mechar s Mag ne, Chicago. POPULAR MECHANICS 817

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816 Traffic Police Dummy at Crossing Warns Autoists to Go Slowly With his star and uniform, a traffic policeman on duty generally inspires cau- tion in many motorists who might disre- Motorists Usually Slow Down When They See This Dummy Policeman on Duty at Railroad Crossings gard or fail to see other warning signs. Practical use of this fact has been made at a dangerous railroad crossing in a Pacific coast city by installing a dummy figure of a policeman near the readside. It can be seen at some distance, is made more impressive by the addition of a large replica of a star on the coat and the sign “Go Slow” printed on a flag the figure appears to be holding. Camp Schoolhouse Built on Wheels Is Moved by Locomotive Where the tall fir timber grows in west- ern Oregon, schoolhouses have been built on wheels so that they may be moved when- ever the logging camp advances farther into the forests. A small locomotive is hitched on and, without greatly disturbing classes, moves the building, children and all, to the next site. Drinking water from springs near by is piped directly into the room, and other conveniences are provid- ed at each stop. Five of these classrooms on wheels are in use, and the county school superintendent reports that they are successful in every way. 818 POPULAR POPULAR MECHANICS Hay Rids Harbor Water of Oil Scum When Scattered over Surface Hay cast on the surface of the harbor waters of Stockton, Calif., removed a thick coating of black oil and grease left by leakage from boats and refuse pipes. Each day a small quantity of the material was scattered in the current and gr: idually ab- sorbed all the scum as well as 400 gallons of fuel oil which had flowed into the basin from a burst storage tank. The tide washed each day’s supply of hay to one end of the channel, and there it was raked from the water and burned. Although a month’s time was estimated to be neces- sary to complete the task, almost all of the oil was removed in a week. Stain-Removal Chart Quickly Tells How to Clean Fabrics A revolving disk chart that shows what kinds of chemicals to use on different goods and for different stains has been de- vised for the convenience of housewives On the outer edge of the upper half oi the card are printed the names of the com- moner qualities of cloth and on the re- volving circle are listed sixteen stains most frequently encountered. By turn- ing the card, the names may be made to coincide according to the particular case that is to be remedied. Toward the cen ter of the disk will be found numbers re- ferring to the chemicals to use, which are listed with directions at the bottom. DIRECTIONS Turn the disk until the name of the stain (if known) 1s opposite the name of ihe | cloth stained The numbers indicate the chernicals to be used and the orurr of their use. Always try the chemicals upon a smal! piece of the goods firs’ Do not mix the chemicals, bul use one ata time inthe given order FOR GENERAL DIRECTIONS SEE OTHER SIDE \. Cold Water -: Potassium lodide, 0% 14. Hydrogen Peroxide 2 Hot Water Craik iS Sodium inate Acetate 3 Alcohol 16 Acetie Acid, 5% 3 Selt (spoonful per pin’* 4. Tartaric Acid 20% 17 ; —- oer 16. Methyl Alcohol arbon Tetrechioride ' mangenate 7. Potassium Cyonide, 10% 20 Benzole 10% 21. Gasoline 22. Ch © 10. Ammonia 23. ae © P Copyright EM Jones —S | Chart That Shows What Stain Removers to Use on Different Kinds of Fabric MECHANICS

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POPULAR MECHANICS

817

Three Stretcher Cots as Carried in Fuselage Compartment; View of Medicine

ons —_—" Chest and Folding Basin between Beds, and Loading of Airplane Ambulance at Field Airplane Ambulances in Army Use Can Land at Low Speed i fforts of the army air service to de \p practical airplane ambulances have been rewarded by marked improvements in facilities for handling patients and in de- signing machines that can land at speeds less than thirty miles an hour, a great ad- intage in restricted areas. Ina plane of recent type, the surgeon or attendant can t between two specially designed litters, nd by the use of levers, may move either patient about to permit a thorough ex- mination of injuries, adjust bandages or Iminister medicines. Another craft can ry eight or more patients at once. The lanes have been found of special use in of all kinds at places lificult to reach by motors or trains. In ddition to the desirable feature of their peed, the aerial ambulances ride moothly that persons suffering from ractures generally arrive in better condi tion than when carried in other ways ] mergency cases Ss) @ Watches were not successfully tactured by machinery until 1840. manu- POPULAR MEC Fountain Pen Made for Draftsmen Produces Coarse or Fine Lines Fountain pens for draftsmen are now being supplied by an eastern firm which declares that its product uses India ink without clogging or blotting and that the point and feed are so adjusted that coarse or fine lines may be drawn as with an ordi nary pen. An automatic principle h been adapted, which is said to regulat: the flow of the ink to suit the breadth ot the line. Hard rubber and brass are the

only materials used and these substances it is claimed, tend to prevent drying and

Fountain Drawing Pen Closed and Open, to Show Point and Barrel Container clogging of the ink in the fountain. The accessory is carried in the pocket as an or- dinary fountain pen. HANICS

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POPULAR MECHANICS Copyright, Underwood & Underw Under Expert Teachers in Trade Schools Where Lessons Mean Actual Work with Real ‘Materials, Skilled Laborers Graduate into Contractors and Apprentices Become Finished Craftsmen Opportunities in the Building Trades Technical Training Is Not Essential, While Willingness to “Rough It” at the Start Pays Well in the End By L. H. G. BOUSCAREN OST of us feel the fascination of the construction business at a very early age. The boy who builds mud dams in the gutter of a city street after a sum-_— struction business as it is now carried « mer’s rain, feels by the great coi this fascination struction firms After a sufficient this country, offe: number of his dams an unlimited sco; have washed out, to our ambition t he begins to realize build things. I s ment istried with improved results. Lad N 1 has made the important discovery of t! value of engineering advice. The co that there is some- “as it is now ca thing wrong with ried on” and his methods or ma- this country,” b« terials. About that cause construct time lad No. 2 ar- rives with a sugges- tion that the next dam be provided with a non-washable spillway, built of brick taken from a neighbor s bric k Courtesy of the Landis Award Committee pile. The ex peri- Miniature Indoor House Put Up by Building Students as we do it now | entirely differer from what it use to be in this cou try, and from what it still is abroad. can illustrate thi from personal ex periences. My ow!

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POPULAR MECHANICS $19 ———=] Anvprentices in Plumbing Class Learning Finer Points of the Trade To- gether with Theories of Economizing in Mate rials; Below, Brick Ma- sons of the Future Run- ning Up a Wall under Direction of Instructors | @©V. «I

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820 POPULAR MECHANICS took him ten years to do it. The history of the construction busi- ness starts with Noah. The ark was the first large piece of con- struction work we have any rec- ord of. It was successfully car- ried out, but took a long time t: do. The next large job was the tower of Babel. As we know. organization troubles developed The superintendents, strawbosses timekeepers and masons who worked on the tower may have been good men in their line, but they couldn’t work together. | think that is what the Bible mean when it says that they did not speak the same language. Now, when an owner wants t build something big, he does n have to go around and collect organization from various part of the country. There are lar construction firms who sta father was a civil engineer of national ready to furmsh him with just the com! reputation. I remember that when I was nation of men he needs for his particu! a small boy going to school he was chief work. Not only are these men good ©uU.&U Modern House Erected in Record Time by Trades Apprentices in Vocation School Where They Get Outside Experience engineer for the construction of the Cin- their line, but they know how to co-o;: cinnati waterworks. That was a $10,000- ate. They have previously worked 000 job. It was thoroughly well done,and many other jobs together. stands now as a monument to his engi- To succeed in the construction field, c: neering and administrative skill But ‘t tain natural qualifications are required i j How Carpentry and Cabinetmaking Are \ Taught to Youngsters Planning Careers aU in Construction Fields . — DADITT AW WECTANTCS

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POPULAR MECHANICS 821 & e, Part of School in Lathing; Below, Plumbing iss Success Depends on Willingness to Do Hard Work lition to honesty, sobriety, and industry, ire req tired in any kind of work. e young man about to enter the con- uction business should possess enthusi- and a willingness to rough it. He ust be willing to live in small towns, or ‘ven in camps and able to work long and rregular hours. echnical training is very desirable, but not absolutely essential. Many of the eads of our large construction firms are ot technical men The man with such in education has more confidence in him- elf, while the man who hasn't got it is ikely to think that he is handicapped by not having it. A man who feels this way , of course, beaten at the start. It is desirable that a young man going into construction, endeavor to learn some- hing ot all the branches of the business, including the purely office part of the vork. He should learn the business from the bottom bv doing work with his hands the job. When I first started out, after graduating from a technical school, I was put to work as office clerk and made up the payrolls, checked the bills, and did all the odd jobs that came up about the ot fice. I began to feel pretty important because I could wear “store clothes” and had a desk of my own. I also had some uthority over the time checkers and ma terial men. One day one of the foremen ime in and asked me to help him measure ’ a mmaiwmwyFefrfeyrsae™ up some lumber. It took quite a long time and we became pretty well acquainted. | had always felt sorry for the men out on the job, but trom my foreman friend learned to my surprise that he and the men on the job felt just that wav about me They had it figured out that I would never

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get anywhere as long as I stayed in the office—and they were right. The next job I applied for, and got, was driving stakes for a surveying party. | soon found out that there is nothing that inspires confidence so much as doing work outdoors, and that the quickest advance- ments come to those who are not afraid to soil their hands. The great thing about the construction business is that it is always changing. There is no chance for a man to get into TRACTOR AND PLOW LAY RADIO GROUND WIRE Plow and Tractor Provide Quick Method for Laying Ground Wires at Broadcasting Station A plow drawn by a tractor furnished a novel and effective method for laying the ground wires at radio station WCBD, Zion, Ill. The ground wires are laid in a network under the surface of the ground beneath the antenna. This is a long job when done by the old trench-digging method, and this novel solution of the problem is interesting. The wire is fas- tened to the toe of the plow, as shown in the lower illustration, and is payed out from the coil and laid as fast as the trac- tor can travel. The wires were laid in parallel rows two feet apart. The total amount of wire laid was 50,000 feet. Origin of Seagoing Words Traced to Legend and Dead Languages Tales of the sea and languages no longer spoken have contributed a share to form- ing the vocabulary of the sailor, accord- ing to a naval publication. The word admiral has been traced to the Arabic, amir-el-bahr meaning “lord of the sea”; captain comes from the Latin caput for head and mate from the Icelandic mati, the equivalent for companion or equal. POPULAR MECHANICS a rut. Opportunities come along quick] and unexpectedly. A man who has bee: doing a little job well, very soon gets chance to do a bigger one. In every larg: construction organization the heads ar: continually sizing up their men with th: idea of trying them out with larger r sponsibilities. To any young man thie possibilities in the construction field ar: only limited by his ambition and willing ness to work. These characteristics ar fundamental guarantees of success. Originally, the coxswain was the man w! pulled the after oar in the captain’s boat known as the cockhoat, a corruption the term coracle, meaning a small roun craft used in fishing. Commodore is dé rived from the Spanish comendador a: naval cadet was taker from the Provenca capdet, also derived from the Latin caput Davy Jones is mentioned often in se: stories but there is said to have been n: such person. He and his locker find the" origin in the West Indian negro ter: “Duffy,” meaning ghost or spirit and Jonah the prophet. The dogwatch wa at first the dodge watch, enabling the men to dodge being on duty every day at th same hours. Starboard relates not to the stars but to the Anglo-Saxon steor board from which the old galleys were steered and larboard is believed to be a corruption of lower board, the opposite and inferior to the “steer” side. POPTITAR MERCH ANTCS

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POPULAR MECHANICS 823 How to Avoid Strain on Your Eyes Is Explained by Expert While the problem of correct artificial lighting is one that often calls for skilled engineers, according to Dr. Charles Sheard of the Mayo clinic, there are certain fun- lamental rules that almost anyone can fol- to avoid unnecessary strain on the eves. The light should fall directly upon he work, should not be in too great con- ist with the general system of illumina- ) and should never be directed into the es, this expert declares. Reflections im polished surfaces also should be ided, as the eve becomes tired in trying in clear images when there is the led brilliance from shiny objects, and kering, unsteady and streaky lights also duce a fatiguing effect. If woodwork, gs, window shades or other objects too much darker than things around em, a glare is caused that is sometimes rmiul, and ground glass should not be ised in panes below the level of the eye, it is said to increase the brightness of ives on parts of the retina not accus- ed to such light Tool for Cutting Holes in Metal Fits in Handbrace For cutting holes in sheet metal of moderate thicknesses, a tool which can be adjusted for any one of nine sizes up to i diameter of two ind three-fourths inches, fits an ordinary hand- brace. Extreme pressure or great effort is not re- quir ed to drill even the largest opening with the cutter. Owing to movable center pin, which can be readily changed for various - sized holes, great lever- ige 1s provided for operation. Per- lectly circular openings with mooth and clearly defined edges are pro duced by the implement, which may also be used to pieree the walls of tanks for the admission ot pipes. Gas Water Heater Made Automatic by Fuel-Control Valve Gas-burning water heaters of a type that must be lighted by hand, can be made automatic in opera tion with little trouble, it is said, by attaching a fuel control valve that turns on or shuts off the gas accord Installing Fuel-Control Valve on Gas Water Heater to Make It Operate Automatically ing to the temperature of the water. The device is strapped to the side of the heatet no holes or drilling being necessary, and consists of a pipe to the main gas sup ply, one leading to the burner and a pilot light. Within the valve part, which comes in contact with the surface of the boiler, are liquid and metal elements which ex pand and contract in such a way as the temperature of the water changes that they automatically release or cut off the gas supplv to the burner. Sixty Thousand Different Stamps Extant in the World Postage-stamp collectors desiring a complete assortment from the countries of the world, will have to obtain approxi mately 63,000 different varieties to make their lists full, for that is the number esti mated to be in existence today Within the last two years, about 4,000 new stamp have been issued by the various govern ments and, of the total, 23,000 are credited to Europe and 40,000 to the other conti nents. Most of the rare old American stamps are said to have disappeared in Germany, as American collectors pur chased them at relatively low figures when the mark was cheap. ————_—___- ---—- - NEE eeEeEeEeeeeeeeeee

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824 POPULAR MECHANICS Railroad Dining Room on Wheels Has Kitchen in Separate Car For special tours through Cuba, a pala- tial dining car, radically different from the ported. The vein was operated by Span- iards in the time of Cortez. They gave it the name La Cucaracha, Spanish for cock- roach, because of the large numbers of the insects that infested the rocks. When the Mexican rebellion occurred in 1812, the miners fled, sealing the entrance to the shaft The secret of the rich deposits perished with the priests, and record in the church writings were lost when the build ing was destroyed. Tales of the treasure persisted, however, and though none could find it, the young engineer who had been befriended by an aged priest during the revolution against Presi dent Diaz and had been told of the mining opera tions by his host, started search. He first disco, ered a new vein, and while hunting near thi property, chanced on the old mine, the entrance to which was almost ob scured by thick growth He was lowered into the pit and was satisfied that his hunt had been re warded by the presence of swarms of cockroaches tie |, err Inside Kitchenless Restaurant Car Where Novel Table Arrangement and Win- on the walls. he ol dow Hangings Give Effect of an Airy Cafe usual type, has been constructed as one of the features of an exclusive six-car train. The conventional center aisle and side tables have been eliminated in favor of five round and one large rectangular table placed along the middle of the car but not in alinement. There are chairs for thirty-eight persons and, as on ocean lin- ers, each tourist is assigned to a special seat for the trip. The hitchen is in the car ahead, thus eliminating odors and hot air from the cooking. Figured-silk hang- ings and cream-colored woodwork are at- tractive details of the decorative scheme. Roaches Give Clue to Rich Gold Mine Lost One Hundred Years Cockroaches and the persistence of a young American engineer have led to the rediscovery of a gold mine in Mexico that had been lost for 115 years, it is re- R26 POPULAR ore vein, said to be ove! sixteen feet wide, is now being worked, according to reports, and | proving rich in silver and gold. Auto Lights Dimmed by Foot Switch to Spare Hands for Driving Placed in any convenient position on the floorboard of the car, a push-button switc! operated by the foot for dimming the headlights ha been devised. It eliminates the ne cessity of remoy ing the hands from the steering whee! to search for a dash key or switch, thus mak ing it easier and safer to drive at night. The connecting wires are easily concealed and the installation does not interfere with other attachments on the car. MECHANICS =

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mon Fim Zi LLL | : AMATEUR 4 MECHANICS Planting the Back-Yard Garden yREPARING the tools and buying the eed and equipment for the back-yard en is one of the most enjoyable, be- being the easiest, parts of being a e gardener. But many a garden that ted off with high hopes in the spring ithered and died in midsummer for of attention, due mainly to lack of er tools to lighten the work of cul- ting. Planning the garden and lay- in the supply of seeds desired, over- ing the tools and making or buying led additions to the equipment, is a vinter and early-spring task, suited in the weeks of lingering cold while weather is definitely deciding to arrive. e garden plan is very necessary for ell-balanced plot, which will bear its imum capacity throughout the sum- providing early and late varieties of e vegetables, and replacing early bear- _with late-maturing winter crops. A considered plan insures the proper oportion of each vegetable, plant- in the proper place to get e right amount of light hade,andthe il best suit- POPI'T An ed to its growth. One of the best back- yard garden plans, recommended by thie department of agriculture, was applied in a 25 by 70-ft. yard in a New York city suburb, and yet in that fairly small space included such permanent plants as grapes, strawberries, currants, beds of asparagus and rhubarb, and early and late peas and onions, sweet corn, cabbage, beans, beets, lettuce, parsnips, radishes, potatoes, kale and spinach, as well as peppers and egg plant. In the main, the department in its bulletins on home gardens recommends he Layout of a Small Back-Yard Garden, the Plan of Which Is Shown on the Following Page that effort be confined to vegetables that deteriorate rapidly when picked and mar- keted through stores, such as corn, peas, beans, lettuce and radishes, while such things as potatoes, which require consid- erable space in proportion to the yield, be 825 MECHANTCS RO”

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826 POPULAR MECHANICS purchased from commercial growers o; HOUSE the grocer. The model garden which the depart ment recommends as an ideal type was

=x ANY boss aoe | surrounded by a board fence, so the own, : —e ¥ er .planted grapevines along it, training y , © ¥| BEANS } “*-~----- ieee : BEANS | 222 CRO » Rocane | cove; cum | * | 8 paper msiucond IEE ¥y| [VY CARROTS) UU OK CARROTS | ------------ YW) jp Y| BEETS et 2 ¥ l O71} [fecers | cABeace YJ [© 4 BEETS oe -¥ fe y LETTUCE ) ¥| ¥ PARSNIPS ¥ 4 LETTUCE | 2xocrop “| % Y y lg PARSNIPS } LATE BEANS Y $ v 2 RADISH BETWEEN ¥ Oo +S Parsnips| PARSNIPS eo ¥ RADISH J o 4 3% & ; <2 . rig Usizittfj Gz a —Yy yyy Uy Ld : ay stp Yj — ° s Z YUU): Yw“tiy Uy; ° & ~ STRAWBERRIES | EXPLANATION M- GRAPES LONG HAND-SLED © - CURRANTS FORK TROWEL eens Left, Plan of 25 by 70-Ft. Back-Yard Garden, Laid Out for Best Results; Right, Tools and Implements Use- ul for the Amateur Gardener

ROR DAADPIT TaD arenmmreaarrmna

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POPULAR MECHANICS ted the garden from the grass plot at e rear of the house. fhe tools for gardening present an finite variety, if purchased from a well- ocked hardware store, but many can made at home in spare time. The epartment recommends a spade, shovel d fork to turn the ground and break clods; a rake for further pulveriz- st) M s ‘fs i] us ia wep ite ve, Homemade Dibber, Strawberry Planter, and Plunger; Left, Transplanting Box for Beans; Below, the Simple and Easily Made Seed Box and leveling; a plain hoe and one of heart-shaped or pointed furrow hoes or laying out rows and dispatching eeds; a hand scratch or finger weeder, trowel and a supply of stakes and line 1 marking the rows. Tor those who ant more equipment a hand weeder, ibble, onion hoe and different varieties scarifiers and weeders are included. 'he man who likes to make his own ools can improvise many of the necessi- es, as well as luxuries, of gardening from other things. An ordinary manure fork ith the tines cut off to a length of 6 or in. makes an acceptable garden spading lork for working in mellow soil. It does not slice the soil, as a spade would, but tends to break it up into smaller and more rregular masses. With heavier vhere a spade is used in turning, a blow r two on each shovelful turned over will rack up the lump. An old hoe, of the plain rectangular artety, can be ground down into a heart- haped one, or a two-pointed weeder that vill get into the close spaces around deli- ate plants and cultivate the ground with- ut injury to the vegetables, while stirring the soil much deeper than the original hoe ‘ould go. Weeding spuds and scarifiers nade of simple loops of iron mounted on ? soils, ree B27 PLUNGING POTS te Baas Phe FLAT OR SEED BOX 2 , fide old broomsticks or other handles will save a lot of back-breaking work. Many vari- , eties of weeding hoes can be made from flat pieces of sheet iron, cut to the desired shape, given a ground edge, and attached to handles. A straight bar of iron, bent into a U-shape, attached to a handle and given a sharp edge, makes a good hand weeder, a short handle being used for close work and a long one for the easier tasks. Garden experts recommend that when a trowel is purchased, an extra amount be spent to get one in which the trowel fastening runs through the length of the handle, terminating in a nut or rivet at the upper end. Ifa broken trowel of the other design, in which the handle fits into a socket, is available, the old handle can be replaced with a long broom- stick, and much trowel work done with- out bending over. A weed spud, made of a flat steel blade attached to the handle of an old shovel, can be made more useful by the addition of a brace in the form _—

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828 POPULAR MECHANICS of a footstep. The dibbers or dibbles (both terms are used) are necessary in transplanting vegetables which are given their start in hothouse frames or window boxes. The dibble is simply a conical or Hat implement which can be pushed into the ground to provide a hole for the plant. After the hole is pushed to the required depth, the plant is dropped in- to it and then, instead of filling in dirt around the roots, the of beans, tomatoes and many other vege- tables may be started in the house in old wooden berry boxes or any other avail able receptacle and attain a good start in life before they are transplanted outdoors. Cucumbers, melons, sweet corn and othe: warmth - loy ing plants thrive when started in old berry boxes comes fort adjoining earth is tamped against the plant with the foot. No earth is removed in making a hole with a dibber, as it is simply Sty pushed aside. «tly Bow ‘ . es HOTBED WITH MANURE ON TOP OF THE GROUND A serviceable dibber can be transplant ing, the bottom of the box ma be cut away and the “hill” planted by sinking the bo» and its con tents in place in the garden, leaving the SECTION OF A HOTBED . : 44 sides just as 4 whittled out of a stick, or made from a branch of a ye nly tree, with the side limb cut down for a handle. The handle part can be softened by slipping a sec- tion of old rub- ber garden hose over it. ' For setting out plants with large roots, such as strawberries, a large flat dibber is used. It can be made from a piece of 2 by 4-in. stock, cut down to a wedge shape, and with a flat piece of 1l-in. mate- rial nailed to the top, projecting all around, to be used both as a footrest in pushing the dibber into the ground, and to regulate the depth of the hole. A handle of iron bar may be added, setting it to one side to give plenty of room for the footrest. It is not necessary to wait for the warm days of spring to start planting, since hot- beds, cold frames and seed boxes are eas- ily made. The hotbed and cold frame may be combined by hinging the glass cover- ing-frames so that they can be raised bit by bit to accustom the plants to the out- door temperature. Early lettuce started in a hotbed will be ready for the table even before the garden can be worked. Hills ’ : 4 +, : 7 tt ot eee forked : , aes 4 aie prea Method of Constructing Hotbed and Installation over the Under- ground Manure Pit > = am 2 they are. The flat or seed box which is kept in the house is perhaps, the most practical device for use by the home gardener f{fo1 starting earl) vegetables. By its use earliet crops of toma toes, cabbage caulitiower, Brussels sprouts, peppers eggplant, and lettuce can be had _ wit! little outlay for equipment. Early pota toes are sometimes forced in the sani way. Seeds so planted germinate and are ready for transplanting by the time it safe to sow the same kind of seed in thi open ground. When danger of frost is over and the soil dry enough to work therefore, the early garden may be starte with seedlings well above the surface Transplanting, if properly done, instead 0! injuring seems to help such plants to de velop a strong root system. Any sort of wooden box filled wit good soil answers the purpose, but thx department of agriculture recommends th: following specifications: Construct a bo» 3 to 4 in. deep, 12 to 14 in. wide and 20 to 24 in. long; place a layer of about 1 in of gravel or cinders in the bottom, and then fill nearly to the top with rich garden 6 . ‘\ + When the time.

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re. lc In et fer en id POPULAR MECHANICS 829 oil, or soil enriched with decayed leaves other fertilizer; press the soil down rmly with a small piece of board, and cratch rows, 4 to 1% in. deep and 2 in. .part, crosswise of the box. lhe seed should be distributed eight or en to the inch in the rows, and covered ith soil, and the box put in a warm light ace and watered. The best location is ust imside a sunny window. Water enough must be given from time to time -o cause the seed to germinate and grow riitv, but not so much as to leak through e box. If the surface is covered with a niece of glass, resting on the edges of e box, it will cause the soil to hold the ater and hasten the germination of the ceeds. When the plants are from 1 to 1% high, they should be thinned to 1 or 2 apart in the row, so as to give room r development. If it is desired to keep e plants thinned out they may be set out 2 in. apart in similar boxes pending trans- ntation outdoors. When the weather becomes mild, the box should be set out- de part of each day, so that the plants “harden off” in preparation for re- oval to the garden. A good watering iould be given the plants just before they e taken out of the box, so that a fair ball of earth will stick to the roots of each. (he hotbed may be built of old lumber, in. high on one side and 8 in. on the posite side, so set that the inclined class top will receive the maximum of sun- hine. The size of the box may be regu- ited to fit old window sash, if they are ailable, or it may be built 6 ft. wide and n any multiple of 3 ft. in length so that tandard hotbed sash will fit it. The hot- ed must not only catch the heat of the sun hut must generate heat of its own through the fermentation of a bed of manure placed beneath it. An excavation about IS in. to 2 ft. in depth should be made, about 2 ft. greater in length and breadth than the hotbed frame, and with walls ned with planks or concrete. A drain to carry off surplus water to a lower part of the garden may be made of tile or by digging a trench and filling the bottom vith loose stones, covered with earth. The excavation is filled to the ground level with manure, and the frame set in lace. The sides and ends are then sanked nearly level with the top of the irame. Three inches of good soil should then be placed on the manure inside the irame, and the sash put in place. After the heat from fermentation has reached its maximum and subsided to about 80 to 1 F., it is safe to plant the seed. The bed should be kept partly dark until the 1 ' ‘ i seeds germinate by covering it with mus- lin, cheesecloth or some other light sub- stance. After germination, the plants will need all the light they can get, except di- rect rays of the sun. Both watering and ventilation also should be carefully regu- lated to get a good growth. Watering may be done in the early morning on clear days, with ventilation following immedi- ately so that the foliage may dry and to prevent mildew. The arrangement of the open garden plot will have much to do with’its suc- cess. The plan should be carefully laid out on paper in advance. Rows should preferably extend from north to south, to imsure an even distribution of sunlight to all plants. All peymanent vegetables, such as rhubarb, asparagus and herbs should be planted at one side where they will not be disturbed every year. Tall vegetables, such as corn and pole beans, should be placed so as not to shade their smaller neigh- bors. Early planted and early maturing vegetables should be grouped, so that later varieties may take their place later on, or between the rows. If pumpkins, squash or other vine plants are to be grown be- tween the rows of corn, they need not be set out until after the corn is well above the ground, insuring that the sweet corn will keep well ahead of the vines, and not be choked by their tendrils or shaded. Rows should be laid out with a marker or with a line stretched between two sticks, in order to keep them straight and evenly spaced, insuring greater ease in cultiva- tion. The department of agriculture has com- piled very complete statistics on the cost _ and labor required in planting and tend- ing scores of boys’ and girls’ school gar- dens and many family plots. Returns from 149 gardens, each about 2,800 sq. ft... show an average cost of $4.82 with about 58 hours’ labor during the season to care for each garden. The same figures show that the small plots of 500 sq. ft. or less, capable of receiving more intensive care, produced a proportionately greater return than much bigger plots. Twelve gardens averaging 305 sq. ft. each pro- duced an average of $6.95 worth of vege- tables, at a cost of 84 cents per garden, and 28 hours’ work on each plot. Eight averaging 1,909 sq. ft. required an aver- age of 39 hours’ work, cost $2.51 and raised $14.46 worth of vegetables each. The best big garden visited by the gov- ernment inspectors contained 8,800 sq. ft., cost $25 to maintain, required 200 hours’ work, and gave an income of $231.82 from truck grown in it.

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$30 Paddle for Child’s Rowboat Rowing with big oars is a hard task for a five-year-old boy, but nevertheless, he is usually determined to row. A small flat- Small, bottomed boat was made specially for a boy at a lake resort, and instead of regu- lar oars, two pie tins were screwed to the ends of a stick about 7 ft. long, as shown in the photo. Using this as a paddle, he was able to handle the boat easily. Simple Bottle-Cork Holder Corks are easily lost unless care is taken to replace them immediately after using the bottle or unless some means is pro- vided for keeping them attached to it. A simple de- vice, that can be removed when the bottle is thrown away, is shown in the illustration. It is made of two short lengths of wire bent as indi- cated, one length being formed to a clamp to grip the neck of the bottle and the other length stuck into the top of the cork. Eyes in both lengths hold them together. In places where a great number of bottles are in constant use, as in physicians’ offices, these holders are very convenient.—Dr. Chas. E. Morse, La Junta, Colo. Pie Tins Attached to Stick Make Good Paddlin Flat- an rasa POPULAR MECHANICS Vulcanizing Golf Balls When golf balls become cut and othe: wise disfigured they are usually discard ed. However, with the aid of an electri: soldering iron, a cut bal! can easily be vulcanized, provided the iron is not allowed to become tov hot. The paint is first removed from the bal] by dipping it in a solu tion of lye, and the cut area is heated with the iron until it becomes soft and plastic at the edges of the cut. Then, by firmly pressing the edge together with the fingers until the rubber is coo! the cuts will become sealed. In some cases, a piece of the cover is lost when the ball is cut bad ly, but if not too large, a piece of a discarded bal! cover may be cut to fit the crack and pressed in when heated. In half an hour the repaired ball. may be repainted by pouring a little gol! ball enamel in the palm of the hand, rolling the ball between the hands until it is thor oughly coated, and placing it on the points of four nails driven through a board, to dry. However, there are some golf balls that are of such composition that they cannot be repaired in this way.—S. A Marshall, Jr., Atlanta, Ga. Device for Child's ottomed Rowboat How to Care for Your Brushes srushes for applying oil paints must be well cleaned atter using, although fo: keeping overnight it is generally sufficient to wrap them in several thicknesses 0! paper. Some painters keep their brushe overnight by putting them in water. !! the brush is not to be used for severa days the paint should be washed out of it thoroughly. Turpentine is one of the most satisfactory materials .for washing brush, but it is expensive, and a brush ca: generally be washed as well! in kerosene which is much cheaper. After washing off a brush with kerosene it should be rinsed with gasoline or benzine, then thor oughly shaken and well washed with soap and warm water. When this has been done the brush should be shaken thor oughly so as to throw out as much water as possible and hung up, with the bristles down, until ‘dry. It should then be off 2 Ge @ 2s ee

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POPULAR MECHANICS pped or protected from dust in. some er convenient way. f much painting ts done it is more con- ient to keep the brushes in kerosene or rpentine. For this purpose hooks ould be fastened on the inside of a pail a close-fitting cover, and the brushes spended from: the hooks, either by drill- holes in the handles or by fitting them loops of string so that they hang in iquid; the bristles should be com- tely submerged, but should not touch bottom of the pail. When kerosene :~ed for cleansing, it should be removed shaking and the brush rinsed in tur- tine before using it again for paint. used for whitewash or calci- ne should simply be thoroughly washed, should not be put in the same liquids hich the oil-paint brushes are kept. hellac-varnish brush should be kept in ol or in the varnish itself. Generally eaking, a varnish brush should be kept he varnish for which it is used. rushes Nursing Kids Artificially nding it difficult to induce young kids drink milk on a California goat farm, method shown in the photo was re- ted to and found practical. Sheet- | tanks, 2 by 1 by 1 ft. in dimensions, ere equipped with three small spouts, over ch were fastened ordinary rubber nurs- nipples. The spouts were simply bush- soldered to the bottom of the tanks. arrangement permits the kids to feed Milk Tanks Provided with Nipples Nurse Kids en a California Goat Farm n a natural way and the only difficulty experienced is that all the kids want tc nurse on the same nipple. 831 Neat Mailbox Rack Improves Country-Road Corner Most mailboxes along country high ways are mounted on posts, and, at some corners, where large clusters of them are “‘Apartment’”’ Mailbox Shelter Improves Appearance of Country Roadside assembled in a more or less haphazard manner, they easily become an eyesore on an otherwise pleasant roadside. However, by «providing an “apartment” mailbox shelter of the kind shown in the photo, this objectionable feature is easily over- come. This shelter is made of a 2 by 4 in. frame and has two or three shelves of l-in. material, and a neat roof to harmo- nize with the rest of the construction. The latter is covered with colored asphalt or asbestos shingles. The mailboxes are at ranged side by side and are screwed down securely to the shelves. The whole affair is given a few coats.of white paint to protect it against the weather. —E. H. Morton, Portland, Oreg. Separating Telescopic Fishing Rods In spite of the light coating of oil which all good fishermen use on the ferrules of their fishing rods, the sections sometimes become so tightly wedged together that it is almost impossible to pull them apart. Ifa slight twisting pressure does not loosen them, do not at tempt to apply greater force, for a good rod is easily strained by such treatment. Instead, light a match and hold it under the outside mem ber of the offending joint until it becomes quite hot. This will ex pand the thin metal of the socket sufh ciently to make the separation of the two sections an easy matter.

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832 POPULAR MECHANICS j ! 1 > - ( LA Ay ar¥f Ly == a \% ~ SJ BATTERY CONNECTIONS Flush Out the Radiator through the Top Opening, Using a Hose Oil the Generator and Starting-Motor Bearings and Drive Chains - —— | an See That the Clamps Are Tight on Both Upper and Lower Hose Connections DISTRIBUTOR WIRING Inspect the Distributor Wires, Tape, and Tighten the Terminals Clean the Spark Plugs Thoroughly and Adjust the Points to the Correct Opening 834 POPULAR MECHANICS

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Preparing the Car for Summer Driving How Owner Can Put Automobile in Shape for Warm Weather and Remove Troubles Accumulated during Winter By J. EARLE MILLER touring season, what does the car was laid up for the winter, or the e that was driven throughout the cold nths, need to put it in shape for eff- nt use? Unless worn parts are to be laced or remachined, the owner can do f the work himself in a comparatively rt time. For the average motorist, re ing the top of the cylinder block to t rid of carbon is too much of a mechan- | task, and should be left for the garage iirman, along with such jobs as re- nding cylinders, fitting oversize piston ngs, tightening bearings and truing up e crankshaft. But, if the car was driven all winter, e owner can easily remove the light nter oil and substitute a heavier sum Wie the approach of the summer them well with vaseline and make sure the terminals are fastened as tight as they can be. At the same time examine the battery fastenings and see to it that the box cannot rattle around in its containe: and so damage itself. The battery leads should be inspected for worn places in the insulation, and if any are found, new cables should be installed or the worn places well taped. Many automobile fires are started by worn-out electrical cables The fastening of the cable to the starter switch should be tightened, if it needs it, and the wires to the distributor inspected, tightened and taped, if worn. The starter and generator are probably badly in need of oil, and at the same time should be inspected for loose or

erade. He flush out | ooling tem, and eis more this than jj] st opening pet- ck to drain he radiator. \fter it is drained, a hose should be in- e layer ;

erted in the radiator in- take, the water turned on, and

worn bearings. \ worn bearing may let the : , armature rub fi against the fields and dam age it so badly a new one will be required, it the trouble is not corrected Spark plugs should be cleaned and re adjusted. A thin dime pressed be tween the con tact points will give the cor

LIGHTS the engine then See That All the Lights Are Burning Properly and That the rect distance . " Contacts Are Tight run for five Many motor- inutes, while the pump sucks the water ists find it pays to install a complete new through the entire system and passes it set of plugs each spring. along with all loose rust nd other foreign matter. If the cock can he removed, so much the better. At the ime time the rubber-hose connections t radiator and engine should be for some anti-freeze solutions rubber, and new ones may be needed the spring. \bout 75 per cent of all the operating roubles of motorists are traced to the ‘lectrical system. <A bit of foresight may vert an untimely halt on a summer's tour. Kemove the battery connections, clean hem and the posts, removing the winter's ccumulation of corrosion, then grease ut the petcock, retween inspected, st POPTITAR A loose fan belt, which allowed the fan to idle along, may not have been noticed in the winter, but with the coming ot warmer weather it should be looked aftet to insure proper cooling of the engine It will pay, too, to go over the lighting system and ascertain that all brackets are tight and the lamps in working order This is particularly true of the tail light The stop light may be inspected at the same time to make sure that when the brake pedal is pressed the stop-light switch works. The wire connection from brake pedal to switch has a habit of growing too long after a few months’ operation, unless NIKCHANICS Ran

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834 POPULAR carefully atched. Quite a bit of work can be done to the running gear by the owner, with the saving bill. Wheels considerable ota garage should be removed and greased. While the back wheels are off, clean the mud and grease off the brake housing and parts, and squirt penetrating 011 into the shackles. Locked brakes, which have wrecked many a mav usually be traced to an accumula- tion of rust in the joints the moving parts. Some of the higher- priced cars use brass or bronze bushings there, but in the medium and low-priced machines, where steel rubs direct ly on steel, rust will ac- cumulate. AN good penetrating oil will car, of Clean Off the Inside dissolve the rust and keep the parts working, and perhaps avert a serious, if not fatal, accident. All grease cups on the car should be re- moved, filled and then screwed down as far as they will go, forcing out all the old grease from the bearings. Then remove the cup, refill and screw it down again. That the only way to get rid of the old dirt and foreign matter with old-style grease cups. lf the car is equipped sure-feed iS with one of the pres- lubricating systems, the grease Left, Remove and Clean the Strainer in the Vacuum-Tank Intake; buretor and Clean the Sediment Out; Clean Out All Carburetor Passages and Adjust the MECHANICS gun will perform the entire task at on operation. Give the body bolts the “once over” with a wrench. They are bound t have worked a bit loo after a winter’s har driving, with resulti distressing bod squeaks. All body bolt should be tightened more or less regular in tervals, if you want quiet and pleasant-rid ing car. Also jack u the body of the car, pr apart the spring leave and coat them with good graphite grease The gasoline syster and carburetor need at tention, too. Th needle valve should bh: readjusted to a summer mixture, somewh: thinner than that use during the cold mont! Next, the drain at t! of the vacuum tank should opened and the water ahd dirt drawn of If it is left in, it eventually will find way into the carburetor. Also, the scree in carburetor and vacuum-tank intake should be removed and cleaned. For the car that was laid up over winter, much of the same general insp¢ tion and overhauling may be applied. properly put away, the radiator aad tank were drained, crankcase oil remo the car blocked up and the tires taken « of the Distributor Points bottom Right, Remove the Strainer in the Car POPULAR MECHANICS

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POPULAR MECHANICS 835 Use Penetrating Oil on All Moving Parts of the Brake Mechanism + ] } Lubricate the Shackles on the Springs t 1 with Oil or Grease | | t - : } GREASING \ Fr 7S SHACKLES Go Over All Parts of the Steering Gear, nspect and Lubricate TTT | Le ~~ oh = \) i») ip D . eam The Steering-Gear Drag Links SPRINGS . Need Frequent Oiling Dry Dirrreawp ASTD“ ry A fw Toto en0o"r

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836 them rust , and paint In the latter case, before putting back, it would be well to clean any from the rims with emery paper both rim and wheel with shellac and graphite. This will insure easy removal in case of tire trouble on the road. With modern tires, which stand up for many thousands of miles, the rims frequently are rusted tight to the wheels when occa- sion comes to remove them. The car laid up for the winter needs the Electrically Heated Sprout Box Aids Garden An electrically heated sprout box of the kind shown in the illustration will enable — ————___—__—_—_——_,, SWITCH i eens re i LINES LAMPS KO pO) Simple Sprout Box, Heated by Electric Lamps, Assists in Early Germination of eds one to germinate seeds early in the spring and thus get good-sized plants into the garden when most folks will be planting the seeds. Boys who raise truck on the side for spending money know that a few days make a lot of difference. Vegetables are high-priced early in the season but later, when the market is flooded with produce the price naturally drops. So the early produce pays by far the biggest re- turns. The device consists of an ordi- nary wooden box with four or six electric lamps set in sockets fastened to the bot- tom as indicated. They are wired up as shown and connected to a snap switch, which is screwed to the outside of the 835 POPULAR POPULAR MECHANICS same general inspection of electric sys tem, cooling plant, starter, generator, run ning gear and greasing. If the batter, was left at the service station for the win ter, it will come back in good condition When the gasoline tank is filled for th first time in the spring, it may be neces sary to open the vacuum tank and fill it then start the engine running until the vacuum feed draws the gas up from th: rear supply tank. box. An extension cord, about 10 or 15 ft. long, enables one to connect it to lamp socket in the basement. An ordi- nary beveled bread pan, fitting snugly over the top, is used to hold the earth in which the seeds are planted. Heat from the lamps maintains a growing tempera- ture in the soil, even in freezing weather However, if the outside temperature is very low, a covering must be provided ove: the box. It will be easier to fit the box to the pan than to find a pan which wil just fit the box; so the pan should be se lected first. It should have tapered side and a wide rim. Then the box should b: built so that the pan will just fit snug) in the top, as shown. The box should be about 8 in. high. Old Stockings Make Mop Old cotton stockings, which are usuall) thrown away, may be made into serviceab|: mops. After cutting off the feet, eac! stocking is ripped down the side from end to end. Then, placing the pieces side by side, sew the up- per corner of each piece to the piece next to it. Tack one end of this assembly to an old broom handle, about 2 in. from the end, and twist a piece of copper wire around them as shown in the left-hand detail. Reversing the position of the handle, so that the strips will hang ove: the end, as shown in the right-hand de tail, twist another piece of wire around the outside, about 1 in. from the end 01 the handle. Each piece is then cut or ripped into ribbons about 2 in. wide, and the mop is complete. MECHANICS

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POPULAR MECHANICS Waterproofing Cloth Cloth or canvas can be readily water- oofed to resemble slickers or oilskins, us making it suitable for boat tops, ck tops, aprons or any kind of terproot clothin g or hats. ike 1's oz. of yellow laundry shave it thin, and dissolve it » pt. of soft water over the re. Bring it to the boiling point, slowly stir in 1 qt. of boiled eed oil. The oil must be add- . little at a time and given time heat up before adding more, d the stirring must be constant ile the oil is being added. It refully made the mixture will esemble mayonnaise dressing. if not made carefully the will separate from the vater. Even after they are operly med, the addition of y pigment to color the mass ll cause a separation of the in- edients. Stretch the cloth to treated in some suitable place, here it will be kept clean, and ply the dressing with a paint- ush Three coats should be ufticient, giving each coat time dry before applying the next. his makes slicker cloth that will iys remain soft and pliable, ind never become sticky. If the canvas is to be stretched on a rame, it should be waterproofed first and then stretched on. If put on first and later water- prooted, it will sag and become very loose after the dressing has been applied.—J. H. Downie, San Antonio, Tex. soap ] Silent Top Buckle for Ford lhe buckles on the straps used to hook he top to the windshield on the older models of Ford cars, often rattle loudly. lo elimin.ate this, many drivers tighten . the straps until a se- Se vere tension is placed m the top. A better remedy is to substitute t heavy leather strap, ibout 34 by 6 in., and provided with a buckle. A %-in. hole is drilled near the end | ot the strap, as shown in the illustration, to receive a stovebolt vith which it is fastened to the metal arm on the windshield. HEAVY STRAP ‘STOVEBOLT \ ts Oe te oe oo iv 8) wa) ~2 Water Dice Is New Game Many water sports of more or less vig- orous nature are in vogue at the beaches, but those who do not care to participate —=—— Water Dice Made of Cork Offer Interesting Game and Give Mild Form of Exercise in these have very little left to do \ more quiet game, which will prove to be interesting as well as mildly exercising, ts shown in the accompanying drawing. It is simply a game of dice played in the water. The dice are made from strips ot cork, like those used for refrigerator in sulation. They are about 2 in. thick and three pieces have to be glued together to make a cube side 6 in. square. The sides are then glued together to form the cube The cork is cut with a sharp knife or with a fine-tooth saw. The required number ot holes on each face are drilled about 34 tn in diameter and about '% in Phe cube is o1\ en two or more applications of white paint and the holes are then filled in with black, each coat being allowed to dry thoroughly before the next is applied.— C. A. Champion, Detroit, Mich deep @ Hotbeds should be built and filled very early in the season: a time before the cold spring weather has disappeared long

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&38 POPULAR MECHANICS ae feof SIDE JAMBS DADOED £xZ GROOVE FOR B INTO HEAD JAMB 7 oe , PARTING BEAD a $= oe a BLIND STOP, 1X2", ! 1 : PULLEY ! FRAME WITH JAMBS, SILL, AND BLIND - STOP ASSEMBLED ~ “aaeneeee HEAD CASING INTERIOR VIEW OF CLOSET SHOWING WINDOW, SHOE BOX AND SHELVES Fie.! LY hoa at RY 20 X 24 WINDOW i y a ee _o_o-sssssoeo oooh > oon 3 bo f § 2 D2" SHELF | be Rf FRAME WITH SIDE AND HEAD CASING ho J - CLOTHES ROD © ADDED hat (| - SHOE BOX ’ ¢ BLIND STOP HH} | % eal INSIDE - EDGE OF PLASTER | | 1X6 HOOK RAIL-+---+ 9" 3 / Stop { HEAD TRIMMER t Y | “ Par a zk az” ' : Ce Ee . —_. ' 1 L finely tet 24 Va" —— ee } Jt 4 : my ' 1 8} he ' it © 1:98) GUS 220% . O _>-44 WEIGHTS | th of / CASING --+f* wwe ft SIDING ~-$A5] | | ! SHEATHING --- | -—ilAeeteen | | iB 7: aes Steet “oe | A WEIGHT ty “We i 2X4 - POCKET ~STUDDING’ wit 4 SECTION OF LOWER TRIMMER —— —_ TRIMMING OPENING 1X3 CLEATS ~ calle a os ae General View of Closet, Detai's of Construc- | tion of Window Casing and Section of Weight | Pocket; Plan of Closet and Fittings; Methods METHOD OF JOINING SHELVES of Making Shelf Joints in Corners and of THAT MEET IN A CORNER Trimming Window Opening Fic.3 e 840 POPULAR MECHANICS

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S \r < a itl ht ’ = <== Part VI—Furnishing a Clothes Closet Tee ideal clothes closet is a moth-proof ventilated room with hanging space clothes and abundant shelf room for rage. Any closet, whether plastered not, can be easily lined with cedar. If ult against an outside wall, light and tilation are readily secured by install- ¢ a window; but if it is an inside closet, fle or vent and ceiling vent will give the culation of air. Shelving, if necessary, be put all round the oset above he hook rail. o estimate the mount of ce- ir necessary line a given loset, multiply by 2% the umber of quare feet of surface to be overed, which gives the lineal feet ot stock, 6 in. wide, needed, allow- ng for waste Group lengths so that the ma- terial will cut economically. Thus, 10- ft. lengths will cut ides and ends ior a closet 4 by 6 ft.; but if the clasas is 645 ft. long it is better to order S of 22-t, lengths for the ends, and 14-ft. lengths for the

Moth-Proofing the Clothes Closet by Lining It with Cedar Is Simple Job for the sides. Cover the ceiling first, running the boards crosswise of the joists and nailing through the faces with six-penny finish nails, since with such thin material it is impractical to blind-nail, when the nail must be long enough to penetrate the plaster before reaching the joist or stud- ding. On the walls, make careful joints at the corners by scribing the ends of the boards; or if this seems too difficult, merely butt the joints, and after lin- ing, cover the joints with tri- angular corner beads. Natu- rally the cedat is left unfin- ished, so that the odor so re- pellent to moths is not diminished. A very good win dow for a clothes closet is the 18 in. by 2-ft. double- hung. The de- tail of the frame, Fig. 2, gives dimen sions of stock for walls of 2 by 4-in. stud ding, sheathed with stock %4 in. thick, and sided with 4-in. material, where the outside casings nail over the siding Departure Home Craftsman ; from this va £359 POPULAR MECHANICS 841

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S40 \) ---= FLOOR CLEAT “a “.=----- BASEBOARD Fig 4 Above, Construction of Shoe Box and Ventilator; Right, Section of Window When Fitted in Place ries the width of the jamb, the sill, and the inside stop, but not the construction. Cut two pieces of jamb stock, 2 ft. 4 in. long, and joint straight to the necessary width, beveling the edges slightly toward the pockets, to insure tight joints where seen. Square one end of each, and, meas- uring along the edge of the groove nearest the inside to the frame, lay off 2 ft. 3 in., which allows % in. for the dado in the head jamb. Set a bevel square to the slope of the other window sills in the house, and mark the dado for the sill, sloping it toward the outside. After dadoing, cut the pulley holes according to dimensions, boring out with a %-in. bit and cleaning with a chisel. Nail on the blind stop, pro- jecting it inside % in. The sill must be ripped along the lugs with a bevel parallel to the jambs, and the inside edge ripped to width, unless there is as little as 4% in. to remove, when plan- ing will be best In assembling, if the dadoes are a little loose, drive a chisel in the back to force the face corners tight before nailing. Cut the top ends of the blind stop % in. back from the lower face of the head jamb and nail on the head stop. Case up to correspond with other outside window casings on the house, and insert the pul- leys, driving a 20-penny common _ nail through each pair behind the jamb. Cut the hole in the wall 2 ft. by 2 ft. 9% POPULAR POPULAR MECHANICS . CORRUGATED FASTENERS? CEILING VENT Fia.5 | i == | ee PARTING __- BEAD —— SASH ---- , SIDE _ ‘iy CASING | il] - STOOL - APRON - Wie SILL----- OUTSIDE APRON —----Ht7"" |) Fic.6 dy in., and trim as shown in the detail, using one stud as a side trimmer and cutting 11 the other between the double-head trim mer above and the single one below. The bottom of the upper header should be 1 in. above the position of the underside oi the head jamb, which is set in a line wit! other windows in the same wall. In setting the frame, rest the head jam! on the end of a stick cut to the proper length, plumb the sides and level the sil! making the weight pockets of equal width and nail through the outside casings Wedge the sill tightly and block above the head jamb, piece in the siding where nec essary, and fit the parting bead in the groove, the head going in first and the sides cutting against it. To hang the sash, joint the edges until there is a clearance in width of %& in Notch the lip rail to fit around the parting bead, slip the sash cord through the out side pulleys, tie on a weight with a bowline knot, and make a single knot in the other end to slip into the groove and hole in t! MECHANICS

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POPULAR MECHANICS where it is secured with a four- ny finish nail driven through it. The de sash is scribed to the sill. t the stool, Fig. 6, case up, put the on under the stool, and fit the stops, ving enough clearance for the sash to le easily after being painted. there is no chance for an outside low, make a jamb in the form of a box, in. square outside, cover the upper with wire screen, and case the face with a plain band, about 2 in. wide, Fig. 5. Cut a suitable hole between ceiling joists and set the frame by ig into the joists through the casing. loor vent is easily made by boring a ber of l-in. holes in the floor in one er where it is not much walked on. en this from underneath if the foun- n vents are not screened. Paper Tells Baking Temperature orrect baking temperatures in the en oven can readily be ascertained the aid of pieces of white paper. The es are put in the oven for five minutes the shade of the paper then carefully |. If it is light yellow the tempera- is right for baking sponge or pound If it is dark yellow the heat is suf- ent for all kinds of layer cakes. The er should be a rich, dark brown if ad and pastry are to be baked. Care ild be taken not to leave the paper in ven longer than five minutes. ¢ Handle Makes Tool Box : of Drawer ; often convenient to remove a tool iwer from the bench and take it to the lo facilitate this, a handle may be attached to the bottom of the drawer, as shown in the ililustra- tion. This will save much time and makes it much easier to handle the drawer, as it gives a good grip and also balances it. In this way e advantages of a portable tool box and drawer can be combined. 6 nA =o. — = 4 a oe. 841 A good height for the hook strip is 5 it. 6 in. from floor to upper edge. Use this rail as a cleat to support a shelf of 1 by 12-in. pine or fir; and if it is desired to continue it around the room, rabbet the end of a long shelf to fit on a corre- sponding shoulder on the edge of the short one, as in Fig. 3. Other shelves may be set on cleats nailed to the walls. Across the ends, or back, wherever con- venient, put a clothes rod, 1% in. full round. This may be made removable by resting the ends in holes bored in the hook strip, or it may be nailed solid. The shoe box illustrated in Fig. 4 is very convenient for keeping shoes grouped to- gether out of sight. It is built preferably in one end, of 1 by 12-in. stock, having a hinged lid hung between end rails to pre vent rubbing against the walls. Air Valve for Football Bladder It is usually a difficult job to inflate a football bladder with lung power and a tire pump is not convenient to use as there Auto Air Valve Ground to avast Makes It Easy to Inflate Football Bladders is no air valve to prevent the air in the bladder from coming back again. A simple remedy is to get an old tire valve and grind it down to the shape shown in the detail. The tapered end is inserted in the tube on the bladder and in a few min utes it can be pumped up to the required pressure—J. FE. Rooney, Hawthorne, New York. @To remove scratches from glass nega- tives make a thick paste of emery flour and alcohol and rub over the scratch with a piece of flannel. oe 1

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POPULAR Portable Baby Yard Most children at the age when they have just learned to walk, get into mischief by pulling down ornaments around the house PLAN SHOWING HOW YARD IS FOLDED Vy Yard Portable Confines Children and Lessens Worries of Mothers and Sisters or get in dangerous places, such as cellar steps, which causes considerable anxiety to mothers or older sisters. To eliminate this trouble the portable baby yard shown in the drawing will be found useful. It consists of four sides hinged together at three corners and held with hooks at the fourth. It can readily be folded to occupy a small and around wher ever needed. The details clearly show the construction and the method of fastening the parts. It can be used outdoors as well as indoors and will then prevent the youngsters from running away, which they have a habit of doing Mart garet Vogt Siddall, space carried at this age N. 3 Moray la, Preventing Uneven Wear on Shoe Heels Nearly everyone has trouble with shoe heels off the outside, which makes it necessary to have them repaired frequently. To prevent this trouble, take the shoes repairman and have him loosen the outer layer ot leather on the heel just enough to insert a small tapered piece on the outside. This makes the heel slightly higher at this point, and pre- vents it from wearing down so rapidly. wearing on to a POPULAR MECHANICS Enameled Ironware in the Home Much enameled sheet steel (grani ware) is now being used for cooking, a1 enameled cast iron for sanitary articl such washbasins and bathtubs. T) quality of the ware can be judged som: what by the appearance; by the absence as of roughness, blisters and bubbles, bare spots, by gloss and freedom from ha cracks and peeling, but the real weari: quality cannot be determined by the housewife except by use. Enameled ware that is readily roughened by the applica tion of diluted vinegar should be regarde with suspicion, although care should be taken to prevent contact of acids of al kinds with enameled surfaces. On no a count should bathtubs and basins be cleaned with acids, but soda alkaline cleaning compounds should always be used. A simple test of enameled ware to apply either red or black ink to the su face and allow it to dry. Upon washing with clear water no stain should be left or Making a Cheap Trouble Lamp A cheap trouble lamp can be made fro a 20-cp. headlight and its socket, a 5-ce1 tin funnel, a tew feet of lampcord, tw battery clips and an old chisel hand The handle is drilled to allow the cord t pass through it, and a slit is sawed in the taper end to receive a wooden wedg: which is driven in after the handle is put into the spout of the funnel. The lar socket is put through a hole cut in th side of the one Oubinen —_ funnel and is mene 4 Y soldered in é \ ; WEDGE é place. After the lamp is ° P CHISEL adjusted in HANDLE the socket, one end of the wire of the lampcord is soldered to the center contact and the other end to the spout of the funnel as a ground, and the clip on the other end of th wire is fastened to some bare metal pat of the car, when used. The second cli is attached to the ungrounded terminal o the storage battery on the car. If the i side of the funnel is painted with whit: enamel, it will reflect the light much bet ter.—F. S. Root, Fall River, Mass. MERCHANICS

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ee \ re ; ¢ A Homemade Printing Press By R. T. POUND UY TTT “MAMI z MNO lh nting Press That Can Be Constructed in Any Home Workshop, and That Will Do as Good Work as a Press Costing Ten Times as Much |HOUGH the press described in article can be constructed of to be found in almost any home it will do good work, and is sufh- powerful to make a clear impres- vith little effort. The chase is large h to permit the printing of letter and also additions, such name and address, to large pieces. he main frame or base is a piece of ood 2 by 8 by 21 in. Across each of this piece, at the bottom, screw 2 in. square, to serve as feet and to vent warping. At one end of the base en with four bolts three blocks of 2- vood, each 6 by 8 in. This forms a s bed which is 6in. high and 8 in. wide. square up a block of 1-in. hardwood tear poste ards, ht the bed and fasten it temporarily th a screw at each corner. The paper be printed is laid on this hardwood ock, which, therefore, must have a plane ce and also be parallel with the type. 1 ( e \ wood may eventually warp, a piece of k flat metal can be inserted to take tvpe pressure if desired. Now obtain a 7-in. faceplate, a piece of h shafting about 10 in. long, and a Dairy 2 plain split box bearing to fit the shafting. Cut about 1% in edge of the faceplate, making a flat edge to slide along the frame. Screw or rivet the shafting into the faceplate, and then file and scrape the face to a plane surface if it is not al ready so. Care must be used to see that the plate face is at an angle of 90° to the shaft, ot} trouble may be experi enced lining things up. Slip the bearing on the shaft, and block it up so that the flat edge of the faceplate ju scrapes the base and the face of the plate is about 4 in. from the press Owing to the differing lengths of bearings, the length of the shaft necessary may be less than that mentioned After finding the position in which to fasten the bearing, a piece of 1'¢-in. shaft ing, 12 in. long. must be obtained for a crosshead. Drilla in. hole through the center of this, and fasten it with a 4-in setscrew to the end of the 1-in. shaft This arrangement allows the crosshead to rotate slightly as the toggle drag links move down. A U-shaped piece with two legs, each 14 in long, must be bent so that the base of the “U” i in. long irom the eTwise 1 when block split is 8% tn. &4 AGE C*° DY A Bw TO Oo QAr

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844 POPULAR cle leasurement The “U”" is made of 4 bv 1 in. iron and serves as the 5% 15 FLAT IRON PRESS BED - INK -— Gut i\\ PRESS b+ --------

~ “ -_ Ps 2x2xea-~ 3° § ORAG LINK —--——- MECHANICS to the center of the crosshead. By thre ing the links tor a generous distancs mn — Mm - fr fi . ~ SETSCREWS — oat) 4" oI Sees Oo} TABLE -, +——— 6’ — INK ROLLER 4 HG uD ~CROSSHE

AD “ o ” y a > = : ~ 2X8 X 2! BOARD---- <= — 7’FACEPLATE.--------- } BEARING —--7 = Constructional Details of the Homemade Printing Press; Below, Assembly of Press, with Dimensions; Ab Detail of Chase and Ink Roller handle by which power is applied to the accuracies in construction can be press \t a point 1% in. from the open _ rected here. end of each leg, drill a hole to fit 1-in. The press is now ready for the cl shaiting, and 4 in., center to center, from ‘This is bent of 5¢-in. square iron, to for this first hole bore another hole in each a rectangle measuring 4 by 6 in. outs! leg and thread it to take a %-in. stud; The joint is made with a ¥-in. setscre 1% in. trom the end of the wooden base or it may be welded. The inside of bore a hole through the joint between the chase must be filed square. One side a base and press bed to take a l-in. shaft with a good bearing fit. Now straddle the U-shaped handle over the press bed, insert a 10-in. length of 1-tn. shafting through the holes in the legs and the hole in the base, and fasten the handle to the shatting. The two drag links are made of in round iron, threaded on one end and with an eye to fit a 44-in. stud on the other end. rhe ends ot the crosshead are bored and threaded to take these rods Sere the drag links into the crosshead, and then fasten the eyes to the handle with ™“%-in. studs By screwing the drag links in or out, the pressure on tl le type can be nicely ad justed. If no changes have been made in the other dimensions, these drag links will be 20 in. long trom the center of the stud S46 POPULAR one end of the edge of the chase drilled and tapped for 4%-in. on each edge. These screws bear metal bars which slide and thus lock the type in place. To ten the chase to the 14-in screw 1s passed throug rh each side of chase into oy setscrews, t agal within the cl facep! ate a should | ‘ — ate, or through plate into the chase if handier. lo test the press, some type should set up and locked in the chase, whi should then be fastened to the plate discarded phonograph turntable, with felt removed, make k table the type with th ing the plate. paper against the on the handle. against the press be found that the sa good in roller Place several sheeis press bed and bear do This moves the bed. It will proba block against whicl e facep MECHANICS + il as you stand fa b ) +

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POPULAR MECHANICS ve bears needs shims behind it to aline vith the type. When this adjustment been made, fasten the block solidly th the four screws provided. It is also sible that, although the type appar- tly bears evenly on the block, there e one or two spots where the impression aint. “Build up” these spots by past- pieces of gummed paper under them the impression is even. Card- rd and blotting paper may be needed nd the paper being printed, or the ) . links may require adjustment. The sure necessary for a good impression as high as 600 Ib. per square inch in case of fine type. the press has been adjusted, it be a help to mount the ink table at back of the faceplate, as shown in the trations. Guides on the chase will -AQ elp the ink roller to do its duty. Paper can be hinged to the frame, and tomatically operated by a cord from crosshead passing over a pulley on the | of the frame and then to the fingers. istable stops will be handy if a large ntity of printing is to be done. Once Teaching Young Chicks to Roost f ung chicks like to keep up their first net of huddling together in a corner ‘ leep and it is therefore rather difficult teach them to roost. Realizing this culty, a poultryman built some roosts he corner of the chick house, which re raised only 6 in. above the ground © that the chicks could easily hop onto em. Later, when they are moved to ther quarters with regular roosts, they ey t! 11 _ . | or TA Se W Lest | Woe rt a P & a Gi a al i a | t] mall Roosts, About 6 In. High, Train Young Chicks it to Roost at Oo snow what to do. These roosts are simi- wt r to the regular kind, but are a trifle lat maller to fit the chicks’ feet. Each unit bl light so that it can readily be removed the » tacilitate cleaning. A Barrel Canoe for Bathers Riding the surf behind a speedy motor- boat belongs to the thrills of many sea- enthusiasts, but the usually shore pleasure timid enough more seekers find Barrel Canoes for Bathers Are Practically Non-Sink- able and Provide Good Sport “kick” in the conventional forms of water sport such as rowboating and canoeing. However, rowboats and canoes are not always available, especially at some small inland lakes, and in such cases a barrel canoe of the kind shown in the drawing is a good substitute. It consists of half a barrel, cut length wise, and an automobile inner tube stretched around it, as shown; these items can be obtained almost anywhere at practically no cost. Each hoop is se- curely nailed or screwed to the staves before sawing so that the barrel will not collapse when cut through. The ends are then cleated and all screws or nails pro- jecting on the inside cut off and _ filed smooth. The inner tube is pulled down a few inches below the gunwale and inflated, which will make the craft almost non- capsizable and unsinkable. By sitting in the bottom and paddling, the boat can be propelled along at a fairly good speed, but if the user stands up the boat will have a tendency to rock, and this adds enjoy- ment as he must then balance it, which is a more or less ticklish feat. @ Frozen potatoes should be placed in a dark place until thawed.

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346 POPULAR MECHANICS Fish-Pole Clamp for Boat Fishing When using more than one fish pole it is, Of course, impossible to hold them all it the same time, or to hold anv when rowing, and [ ~ ge ee they have to a be laid down. ), A SCREW It often hap- Y "2 | pens that the \ ms hook is caught in weeds while rowing or drifting and the pole is pulled = over- board, Or a2 big fish jerks it into the water. To avoid _ losing the pole, the clamp shown in the draw- ing has proved use- ful. It con sists of an & in. strip of flat,: s pt ing metal, prefer ably brass, about 1 in wide and bent to the shape indicated. It holes are drilled bolt, which is and two for a is doubled through it used to tighten the clamp on the handle screw or of the pole. The legs of the clamp are bent outwards slightly so that they can readily be pushed over the gunwale of a rowboat. Poles provided with such a clamp can be left without attention as they cannot be pulled into the water very easily.—L. B. Robbins, Harwich, Mass Electric-Cord Troubles Much of the trouble experienced with electric appliances is due to improper care of the cord Do not allow the cord to be- come badly frayed, and avoid sharp kinks and twists. It is a common occurrence that individual wires of the stranded con ductor forming the cord become broken inside the insulation; do not, therefore, tie tight knots in electric cords, do not pull them taut continuously over sharp cor ners and do not pull them tight nails in hanging them up lwo nails or placed about 1 in. over hooks, POPULAR apart, so that the cord may be hung by the attachment at the end will found satisfactory for keeping extra cords. Vacuum-cleaner cords should coiled loosely like a lariat and hung over one hook on the appliance only. The lower hook should not be used, as th encourages the tendency to wind the cx tightly, and shortens its life. If troub) is suspected, take the cord to an electri dealer to be fixed at once Drying Prints Quickly One day I found it necessary to d: some photographic prints quickly, whi could not be done by the old method laying them on a sheet of cheesecloth. took a piece of plate glass, of which t! dimensions were about 1 in. less than tl size of the oven in the kitchen range, a1 laid the prints on this face down, rollin them with a print roller to press most the water out and make them lie flat. T! glass with the prints was then laid in t! oven of the range, after making sure tl the oven was not hot enough to the paper. In twenty minutes the print were thoroughly dry and the same metho was thereafter used with equal success Burton F. Moore, Wendell, Idaho. SCOT Plate-Glass Scalloping Tool In our November issue of 1924, on page 862, a tool was described for scalloping plate glass. Unfortunately, an error crep in the drav ing of t hi tool, and als in the accon panying de scription ot it and the too would b rather it practical. | the drawin referred t the tool wa shown t have tw teeth. Thi would mak large and i regular chip when used the plate glass which, of course, is 1 desired. The tool should have only o1 tooth, as shown in this drawing, so th: the glass will chip off neatly and evenly resulting in a good scalloping job. MECHANICS

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Getting the Best from Your Set

Little Things That Make the Set Perform as It Did When It Was New

I: PING the radio receiver operating cause he built it himself, but also of the \ efficiently is a simple matter, but like manufactured apparatus. The owner pet other piece of electrical mechanism, haps has noticed that his set seemed to t demands a certain amount of at- work better when it was new; this is usu 1 at regular periods. This is true’ ally not all fancy, but is very natural ly of a set the owner is proud of be- When it 1s new, the batteries are fresh, the

Dust Right Is le b 1 | I t | j t, Tightening the Socket aii } ae i ty erminals, and Above, jo rom the Set, ] I Testing the B-Battery < Testing the Dry Cell 1]

DOAPTITIT AR MRCOH ANTICS QAO

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S458 POPULAR contacts are clean, connections tight, the ; are tree from dust, bushings e instrument 1 have not had time to wear and the re ceiver is efficient in every way. This is the condition that must be maintained if it is to continue to give satistaction he first indication of trouble usually is decre ised volume, or lack ot clear tone. (he operator is tempted to blame the weather, or static, or even speak unkindly of the broadcasting station, when the trouble really lies in his own set.. One of the greatest trouble makers is dust, wluch finds its way into all types of cabinets and MECHANICS tighten it. After the socket posts ha been tightened, see'that all the spring cli in the socket are sufficiently in raised t make good contact with the prongs ont base of the tubes; if not, use a buttor hook in the manner shown in one of t! illustrations to raise the contacts. If socket is of the side-spring type, see th these springs are in the correct positio to make good contact. The prongs the base of the tube should be cleaned se eral times a year. Many times this wi eliminate circuit that are very dit ficult to trace, and good contact with tl +} t 4 Ol noses ( is an enemy to good reception; it creeps tube in the socket is absolutely necessat between the plates of variable condensers if highest efhiciency isto beobtained. Clear and moving contacts, and, if allowed to the ends of these prongs with a sma accumulate, will eventually short the con nail file or fine sandpaper. Handle the densers and spoil tubes with care the contacts. To as they are “service a re- Cw irs’ test of the three-tube Cockaday receiver fragile, and ofte ae a a 7 described in the April issue of Popular Mechanics ' Sa prsenchubtl heal Mss brought twenty distant stations, despite adverse a slight k a moave the tubes ‘ ns, inclu g severe static, unusually marked on the table , . i na | hae. tine . de stee Pee and place them g, and the fi tl at the test wa made in a steel sufficient { a 7 et rced apartment hotel in the heart of Chicago ’ out of danger ot Che stations heard included two in Kansas City, Mo., break the fi accident ° Pim a one in Dallas, Tex., two in Cincinnati, Ohio, two n . ab - accident ; di Pitcbargh, Wa, ene in Schenectady, HM. ¥.. Yelerecs ment. Tht connect the bat City, Mo., Troy, N. Y., Cleveland, Ohio, Hot Springs, especially tru teries, marking Ark., Shenandoah, Iowa, Davenport, lowa, and of the drv - ce a. Angeles, Calif., as well as five Illinois towns outside , leads with little of Chicago Stations as widely separated as Kansas tvpe of tu be -ardboard aos City, Shenandoah and East Pittsburgh were brought oy: ine | cardboard tag sick. aad - I N -Xamine ft In | ne iowd speaker with goo volume, o groun ‘ to insure that connection was used during the test, an inside counter blades on tl ’ ‘ r } } . they will be con poise of sixty feet of bell wire, strung around the acks to ascet! e , 7 . picture molding, being attached to the ground terminal } a nected again of the receiver The counterpoise was substituted for tain that th-« prope rlv. and the ground connection in order that the set might be make prope then yf siete th switched over at will to a B-battery eliminator, in which t t 1 tl e emove e case the lighting-circuit connection to the eliminator contact, ane set from the becomes a ground. With ordinary dry batteries the the conta: erm a The counterpoise gave the same distance and volume as the . ie = Cab inet. ie original ground, while with the eliminator both dis points are Ire¢ first thing to do tance and volume were increased. The outside aerial in from dust a! ; . ling 1] oth cases consisted of 94 ft. of enameled-copper wire Ider fin Is to sé a sma , Pittsburgh, Cincinnati, Schenectady and Hot Springs soldering flu camel's - hair could be heard clearly on two tubes, while Davenport, Jacks are poo brus} les scone of the Cincinnati stations and the five Illinois roa / ’ TUS to clean sadeasters all worked the loud speaker on two tubes things at best in off the dust ac- J. E. Miller, Chicago, II! radio. circuits, cumulated onthe and must be surface. Any kept in good dust that has settled between the plates of the variable condensers must be removed also; this can be done with an ordinary pipe cleaner, or a small brush supplied by the radio dealers for this purpose. Dust between the condenser plates often causes noises similar to static. Wipe and scrape all movable contacts and wiping joints, as many times a film of grease forms at these points, which in time will cause trouble Socket binding posts should also be tightened, and a special tool in the form of a socket wrench facilitates this, although it be accomplished with a small pair of pliers. Care should be taken not e so much pressure that soldered ‘onnections will be broken; a slight move- ment of the wrist will be sufficient to find uit if the knurled nut is and to c an to us loose 850 POPULAR condition at all times. Place a plug in t! jack and note if proper contact is mad: in opening and closing the circuit. Gri leak clips must be clean and so bent tl they grip the leak cartridge tightly; al make sure that the machine-screw at soldered connections to the grid cor denser and leak are secure. After car fully going over all soldered connecti to see that everything is tight, examine t! connection between the rotor and tionary plates of the variable condense frequently this connection is made means of a “pigtail,” or short length flexible stranded wire If this wire frayed, renew it; if merely twisted, rot the dial until the wire is uncoiled. Mo variable condensers have stops to preve such trouble, but some unfortunately ha Ol t MECHANICS

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3) POPULAR MECHANICS 849 \S t Springing Socket Contacts; Fig. 6, Cleaning Condenser; Fig. 7, Testing Storage Battery and Fig. 8, Cleaning Prongs on Tube Base \ well-soldered connection to the that the dial has not s ipped on the shaft it of the condenser 1 absolutely neces- of the condenser lt this has happened, vith this pigtail connection. Some_ it will account for any discrepancy that lensers have a wiping contact and this mav have been noticed in logging stations ive attention; wipe it carefully to For example, when first logged the sta ve anv trace of grease, and, if neces- tions would come in regularly at certain tighten the spring. While working points; then later, for no apparent reason, , ondensers, it will be best to see these same stations required a different POPULAR MECHANICS 851

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850 POPULAR MECHANICS Upper Left, Testing Plug Contacts; Upper Right, Grid-Leak and Condenser Contacts; Lower Left, Contact on Jack, and Lower Right, Cleaning Top of Storage Battery dial setting. If this is the case, release the little setscrew in the dial to free the latter on the shaft. Now place the finger on the rotor plates and move them until they are in the “all-in” position, then set the pointer on the dial to the maximum reading on the dial scale, and tighten the setscrew so that the dial cannot move on the shaft, being careful not to change the position of the pointer in relation to the position of the movable plates. The dials will then log the stations in the proper place again. See that the rheostat shafts are gripped tightly in the knobs, and that the pointer is in the proper position to indicate the off position. There is a setscrew on the pointer knob to fasten the latter to the shaft; this can be reieased and the knob readjusted to the right position, if neces- sary. In some cases this screw is it collar at the rear of the rheostat assemb instead of in the knob itself. If the « lar is loose, it will be necessary to u pressure to fit it tightly against the bla and lock washer, or star-spring wash so that the blade of the rheostat will mal a good wiping contact on the resistan winding. Finally, examine all bind posts on the set, and make sure that t nuts on the underside are tight and m ing good contact with the soldering on the wiring. We have now finished with the intert assembly of the instrument, and are rea to replace the set in the cabinet. Betor connecting the A and B-battery wires, te the batteries. Use a small d.-c. voltmete for this purpose; this should have a sca reading from 0 to 50 volts, and can be o POPULAR MECHANICS oe

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4 } 1 > WS6e pe used POPULAR MECHANICS 851 rom any dealer in radio supplies it $1.50; every owner of a radio ould have pne. 1 A flexible cord etal terminal and another ter- the case of the instrument are king the connections for the Hold the terminals on the voltmeter sition shown in the illustration } imeter for rtant thing enough to get a reading. Never testing B-batteries; for the operator to he voltage that the battery will to the plate of the tube. Each unit should test not lower than ts in a fresh battery, and when this falls to 17 volts, the battery should arded. Never use old batteries as ters for fresh ones. The old batteries resistance to the circuit and soon ren- he good should be freed of corrosion. If battery clips are used, see that they are clean and make good contact on the battery termi- nals. The positive terminal is indicated either with a cross or the letter P, the negative terminal by a dash. or the letter N. If you find the positive terminal of the battery badly corroded, clean it care- fully and cover it with a coating of vase- line; this will prevent further corrosion. Remove all electrolyte spray from the top of the battery with a cloth moistened with a weak solution of ammonia. Care should be taken not to let any of the bat- tery solution come in contact with cloth- ing or rugs. It is a good plan to keep the storage battery on a rubber mat or glass plate. The storage battery should be tested with an instrument known as a hvdrometer, [J ries inefh- j hesides »adauce ises in lt dry e used batteries, ecase e UV-199 ] rei. these re tested e same ner. When- he work- ltage of \ - battery w the tbe-fila- t voltage, Is are onger wuse- Ta d 10 ittery serv ind must T ¢ plac ed. e first sign lving A-bat- cells is the ing off in lume in the elver Diagrams ] “~ Fig. 13, Setting Condenser for Proper Dial Reading; Fig. 14, Ex- amining Pigtail Connection on Condenser for connecting the \-batteries for the number and type of t are supplied by the maker or igner of the instrument, so we need sO into that detail here, except fora rd of caution: Be sure to hook u, these tterie Ss in exactly the same manner as re thev were disconnected. The wir- tor A-batteries should be heavy cop- re to reduce the ch takes place in smal ge A-battery is used, all connections energy loss 1 wires. If a which can be obtained irom anv battery or ° radio dealer for 1 about 75 cents : [he operator should provide a l-qt. wide- mouth bottle in which to keep the hy- drometer, and a supply of distilled water. Never allow the water level in the cells to tall below the plates, but keep the level. by adding distilled water, at least 4 in. above them. The hy- drometer con- sists of a glass tube or barrel with a rubber bulb at the top, a rubber tube or nozzle at the bottom, and a_ weighted float inside, marked with graduations on the neck The graduations usually run from 1.300 to 1.100: the decimal, however, is often omitted on the scale To test the storage battery, unscrew the caps on the battery cells, and insert the nozzle of the hydrom eter into the electrolyte in the manner shown in the illustratior Compress and release the bulb at the top several times to draw the electrolvte up into the instru 1 4 ment, then withdraw the nozzle Che

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852 barrel of the instrument should now be about half full of the solution and the float will ride at a depth depending on the amount of charge. Hold the barrel ver- tically so that the float will not touch the sides of the glass tube. When the float is at rest, obsefve the point on the scale reached by ‘theliquid ‘level. It will be found that the specific gravity of the fully charged cell will vary with the make and age of the battery, the full-charge point ranging all the way from 1.275 to 1.300. An old battery will show a lower specific gravity than a new one, so that a reading of 1.250 to 1.275 may mean a full charge in an old one. Never permit the read- Connecting Radio Dry Cell Batteries There are several tubes on the market of different voltages, and the novice 1s often perplexed just how to connect the Fio.! PARALLEL, 15 VOLTS 3 DRY CELLS IN Fic.2 2 DRY CELLS IN SERIES, 3 VOLTS Fic.3 6 DRY CELLS iN SERIES- PARALLEL, 3 VOLTS Three Methods of Connecting Dry Cells to Suit Tubes of Different Voltages dry cells to suit the tubes. The WD-11 and 12 tubes are 1'4-volt tubes, and op- erate on one or more dry cells, one cell be- ing usually provided for each tube. If two or more cells are used for more than one tube, they are connected in parallel, as shown in Fig. 1. No matter how many dry cells are connected together in this way, the total voltage alwavs remains 1%. For 3-volt tubes, as UV-199 and C-299, the re- quired voltage is obtained by connecting two dry cells in series, as shown in Fig. 2. With this arrangement the positive of one cell is connected to the negative of the POPULAR MECHANICS ing to fall below 1.180 before recharging the battery. Replace the electrolyte, after the reading has been taken, in the same cell. Be sure to test each cell in a bat tery, as one may consistently read loy than the others, and this should be tended to by a battery-repair man. Cl the hydrometer with clear water bef: laying it aside in the bottle, as the soluti will quickly ruin the rubber connectio: It is a good idea to have a small light ne the battery so that the test can be ma easily and the level of the electrolyte « termined without guesswork, as is oft the case when the storage battery is cated in an unhandy position. other. When two or more 3-volt tub are used, it is good practice to use t\ dry cells for each tube, connecting the: in series-parallel, as shown in Fig. 3. T! gives 3 volts and a maximum amperag A higher voltage than that for whic! tube is designed should never be used, a: the filaments should never be burne brighter than needed for good results Improvising a Shaft Extension A spool can be used to form a collar « any instrument shaft where an extensi is required. A tapering slot is cut lengt wise in the spool, as shown in the upp: illustration; a hole is then drilled at rig angles to the axis of the slot to admit small bolt or machine screw. Wood, fil or rubber rod, Y% in. in di- SMALL BOLT-. ameter, can , be used for the extension spindle. The shaft of the condenser or other instru- ment to be extended is then inserted in the spool, and the length of rod in the other end of # INSTRUMENT ia] ~ SPINDLE _ RUBBER SHAFT the spool. The bolt or machine screw is then tightened and the extended assembly ready to slip through the panel. Ajit: the dial is adjusted, the unit is ready f: use. This places the instrument farth« from the panel, eliminating body capacit POPULAR MECHANICS

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HOW to LAY OUT AND DRILL RADIO PANELS | \RKING ut radio \ prep- 1oOn tor ng is a e 10b, but, every mechan- isk. there ight and ° way it In case Oo f o panels, |e wey methods ing them d mark he } any ch will ood re- inthe of an ex- or one If a 6-in. steel scale is available, it will be found handier ft many oft measure- ments than the rule, but it is not essential. In addition tothe tools, a sheet ot oT ] > { fairly heavy Ca rdboa rd is necessary. Bris- tol board is ideal for the purpose, but if this is not at hand or can- not be obtained easily, any kind of cardboard that will lie flat and show a pen cil mark dis ; med to )) rhe Before It Fastening the Template to the Panel by Means of Small Clamps ag tinctly will serve 1] Is Laid Out verv wel Lhe od de- board must be C n this article, however, is the one cut to the exact size of the panel to be been found by Popular Mechan lio laboratory to be the simplest for teur, and to produce uniformly results wherever recommended: for reason it is the only one considered ile we have found radio fans that Oo a good job oft laving out panels ut any more elaborate equipment 1,1 oid 2-ft. rule, and an ice pick to scriber, it is a fact that the job h easier by the use of proper hichare er numerous expensive ur small C mps, a small er, a prrek a small pair machinist’s @i- T all of which be obtained + e mue en-cent store ule and a lead laid out. Look over the panel and select the bet ter side for the front. Hard-rubber pan- els are usually stamped on one side with the name ot the maker. and this deter mines at once that this side will be the back On other panels, the side to select is the one that has the better finish, or shows the fewest abrasio1 marks Of course, if one is using a “mahoganized” panel there is only one side to elect tor the front Now fasten the cut sheet Oo! ( rd or bristol board to the front side of the panel by means of the little C-clamps n in Fig. 1, taking care that t lhe flat and that the edges are even wit the edges of the ire 917 hea ' >] Thi Tea are al th IS gives , enn f ’ The Few Tools Necessary for Laying Out Paneis, To- a rh ne ‘S necessary. gether with the Cardboard Tempiate a surface corre- POPULAR MECHANICS 855

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854 sponding exactly to the panel, on which the location of the various holes may be laid out in pencil as shown in Fig. 3. A template of this kind should always be em- ployed, as mistakes will happen, and it is easier to rub out a few pencil marks ona piece of cardboard than it is to determine which of a number of scribed lines on the surface of the panel itself are the correct ones. It is assumed that the reader is laying out his panel from a diagram; the layout of an original design will be treated later. After the location of all the holes has been marked by means of cross lines measured from the edges or center of the panel, the centers of all the holes are marked by means of the prick punch, as in Fig. 4. hold- ing the punch vertically, and striking it hard enough to force the point of the punch through the cardboard and into the _ sur- face of the panel. The sizes of all the holes should then be marked on the panel template, for convenience, and the tem- plate removed. The marking of the screw holes for mounting condensers presents a problem when a template is not furnished by the manufacturer. There is a very good tool made for this purpose, but in the absence of this, a template may be made as shown in Fig. 5. Take a square of card or bristol board, and cut a small hole in it that will be a tight fit over the shaft of the conden- ser. Press it down until it is in contact with the frame of the instrument, and feel for the holes with the point of the punch. When found, press the point through the cardboard into the holes. Now, when the hole for the condenser shaft has been drilled in the panel, the shaft can be put in place from the back, the template slipped over it again, as in Fig. 6, and the Making a Rough Layout of the Instrument Dials on the Front of the Panel POPULAR MECHANICS location of the mounting holes maz easily, taking care, of course, that they marked so that the condenser will b: the proper position when mounted. shaft hole should be a snug fit for operation, but should be reamed out aft ward to clear the shaft by at least “2 i: Drills for radio work should be selec with as much care as for drilling m: Cheap drills will not remain sharp, when dull, will increase the tendency chip the edges of the holes. Get g: drills and ke them shart Never dril panel with supporting on a block a flat surf: If this prec tion is. take and the dr are sharp, the will be little no chipping the edges the holes at t back Fig shows how 1 drilling is d on a good ad: ing block has been fou that with | rubber it is 1 important f which the panel t drilling done; w bakelite formica, ho there is a slight tendency for holes to chip around the edges at 1 back. In general, therefore, it is safest drill from the front of the panel, and th: if there is any slight chipping around t edges of large holes it will be at the ba where it will not mar the appearance the set. It is a good rule to drill all ho with a small drill first, as there is not much tendency to “run off” with @ sn drill, and chipping by the larger drill u afterward is less likely to occur. For h« larger than %¢ in., it is good policy drill first with a %4-in. drill and then re the hole to size as in Fig. 9. With a go reamer, there will be no chipping of t edges of the holes. When countersinking, the operat: shown in Fig. 8, be careful to see that t! drill is held vertically. This operati side ever, POPULAR MECHANICS soft wood wit ¢ +

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itl t t! iti POPULAR MECHANICS 855 be done with the panel held in the lesired. The only precaution to erved, besides the foregoing, is to the countersink is neither too too shallow. In the upper part ¢. 12 is shown the effect of counter- de too shallow and too deep. In ise the screw projects too far; in her, the countersink shows around edge of the screw head. It pays in nce to be careful to get the coun- nks of the proper depth, either with ead screws, like the examples shown, Hat-head screws. en the reader is laying out a panel wn,’ there are one or two hat are not apparent at first sight, hat may spoil the appearance of et if not observed. The first thing is to lay the panel down on a table pread the various dials on it, shift 1 until a pleasing layout is secured lown on a rough sketch the position e dials, and then refer to the circuit gra Go over it carefully and see if layout will give the shortest possible between the instruments on the nel and those on the baseboard. It may essitate several trials until a compro e between good appearance and effi- wiring is obtained. When this is ne, a cardboard template may be se- Laying Out the Position of the Instruments on the Template Marking the Panel through the Template with the Center Punch Punching Template to Fit the Holes in a Variable Condenser Using the Template Made as Above to Mark the Holes in the Panel; Left, Drilling the Panel with a Hand Drill

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856 cured to the panel and the actual layout made on it. One point that many ama- teurs overlook is that _the edges of the panel slide in grooves in the cabinet. The depth of the grooves -—___——- 8" POPULAR MECHANICS this side of the center of the panel. however, there is a rheostat knob at and another knob at E, the center of t condenser would have to be shifted f1 D to F, in order to make the panel app: well-balanced. The matter of balance the panel is an important one, as upon depends the appearance of the set wl Countersinking and Reaming Pane!s: Correct and Incorrect Countersinks, and Method of Laying Out New Designs which is usually “46 in., as in Fig. 10, should be measured and lines repre- senting them marked on the template. These lines are then to be taken as representing the edges of the panel for the purpose of the layout. It is best when laying out the panel, in a symmetrical design, to forget the edges of the panel and to lay off all the holes from the center. In Fig. 11, for example, we have a 16-in. panel, and the center line B can be marked 8 in. from the end, as shown. As the cabinet groove is “4 in. deep, however, line D, which may be the center line for a condenser or other instrument, would not be laid off 4in. from the center B, but 3°%2 in. from it. This would be the layout if the instrument on line D was the only one to be placed on Regulating Heat of Electric Soldering Irons Many radio fans have had considerable trouble in making the heating elements of electric irons stand up any appreciable time. The trouble probably has been that it is too much trouble to turn off the juice as often as necessary, the reason being that the iron takes too much time to re- heat. This trouble can be avoided nicely if the fan will secure a “dimlite” socket, “O(a r INCORRECT .-f + © == D F Fig.il CORRECT Fig.12 Fic.10 a However, efficiency must be sacrificed for appearance, and the thi completed. of first importance is “how will the operate?” In most cases, however, t! builder will find that there is some arrans ment of the instruments that will not o1 be efficient, from the wiring standpoi: but that will lend itself also to the produ tion of a well-balanced panel. obtainable at any electrical store. The ting is mounted above the workbench any standard socket. With the pull cor lengthened to be within easy reach of t operator, all the trouble of a cold iron w be done away with. The iron wiil rema sufficiently warm to run up to full heat a few seconds and no time will be lo neither will it be burnt out. The cost this fitting is slight compared with that replacing soldering irons for radio wor Georger —L. H. Buffalo, N. Y.

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T nT ity | OUD-SPEAKER volume may be ob- 4 tained from a simple, inexpensive -tube set, built and thoroughly tested Popular Mechanics laboratory. This has a range on the loud speaker of 50 es, will easily bring in stations 1,000 es away on the headphones, and can be t for about $35. With all Chicago stations in operation, in spite of the fact that the set was erated within half a mile of the power- WGN, no difficulty was experienced in ng in any local station, or in cutting of them out entirely. In a two-hour t on “silent night” 15 stations, ranging m Omaha, Nebr., to Washington, D. C., from Minneapolis, Minn., to Dallas, ex. were ————— ged. Dry- Pa " tubes are | landthe of opera- is much er than larger but at no- crifice of udibility or electivity. ithin the nge of the t. One of e greatest ad- ntages of the receiver is ease of con- truction, as ere are no ils to wind. In addition, by imply chang- ing the honey- mb coils, the ntire range of ave lengths iv be cov- red, from the igh of the th ———__ — ———— —— rent tions to the low of the amateur stations. In tuning, connect the A and B-batter- ies before placing the tubes in the sockets. Make the first tests with the phones. Plug in at the detector jack, push in the fila- ment switch, and turn up the rheostat nearest this jack until you hear a swish- ing sound in the phones. Turn the vari- able-condenser knob at the left to the zero point, and slowly rotate the variable-con- denser knob at the right until a station is picked up. The variable condenser at the left is for fine tuning and to separate sta- tions that cannot be tuned out with the right-hand condenser alone. It will be found that best results are obtained by using the smallest amount of filament cur- necessary | to operate the detector tube Back the rheo stat off until this point is reached. If more volume is desired, re move the plug from the de tector jack and insert it in the horn jack, leav- ing the detector rheostat in the same position as before. Now turn up the second rheo stat until the signal volume is clear and strong. Turn the rheostat no further. If the station re- ceived has suf- ficient volume, the phones can now be re- ommercial nd ship sta- Here Is an a > § Set That Will Give Ample Volume on oud Speaker for Local Stations moved and the loud speaker 857 POPTITL_AR MRCHANTCS Qag

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YINVI3dS a8Nl-OML gno7 WISNIGNOD INV ¥V¥371 GINo % ‘ - JIM YVEBSNG SHLONI1 SMINIS GN OV3IH-1WA $381 662-9 4O 661-AN S1SOd ONIGNIG GIAVHON] e ’ GIGLS TWNIWY31 Oy Fr = 101$ YINYMOISNVY! “O3Ns-O10NV ¥V371 Aino OIN-Z Sdl1D Mv31-dIN9 HLIM YISNIGNOD AIXD G4iIN-S2000 SL13N9OS JSNL 11399 -AnNad STVIO Y3INYIA WISNIGNOD JIWVIYVA JLVId-l! VISNIGNOD JIGVINYA JLV1d-€2 MQVP “190 LINDUID-31EN0G ADSVC NYOH LINDUID-JIONIS SiVLSO3HY WHO-OE HOLIMS LNIWY 14 SIJTONY SSVue ONILNNOW WOOD WOD GNWODAINOH NaNl-Os auvog3sva +ix ix? TAaNVd #1 xix? t LSM Wikt3Llvw MECHANICS LAR POPU

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POPULAR MECHANICS 859 ved in. Any good loud speaker can sed with this receiver. When the in- ment is not in use, be sure to turn off filament switch, and turn the rheo- s to the off point. ere are no special details necessary as onstruction, as the blueprint illustra- of the instrument layout and wiring | is self-explanatory and the material ippears on the same page. All of the nd B-battery leads are brought out ugh the rear of the cabinet, as well as ierial and ground wires. The bind- posts indicate the proper A and B- Front of the Set with the s; Right, Rear View, Show- the Compact and Neat Ar- rangement tages. A word here v be of assistance, how- er. The reader will note e post marked A-posi- e and B-negative; both ids can be brought to his post, or the \-positive innected to this post and e negative B-battery lead to the A-posi- ve terminal on the dry cells. The de- ector B-voltage is indicated on the bind- post marked 22%; this can be varied some detector tubes work best on 18 Its, especially when the B-battery is esh. For the amplifier, plate voltage 90 Its can be used, as indicated, or it may e found that 67% volts are sufficient. lhe A-battery consists of three No. 6dry lls connected in series. Two 45-volt pped B-battery units are used; these are nnected in series and tapped off as fol- vs: The negative lead of the first B- ttery unit is connected either to the A- sitive post on the terminal strip, or to € positive terminal on the dry-cell A- f mailing. battery; the 22'%4-volt positive lead is con- nected to the terminal strip, and the 90- volt B-battery lead taken from the further end of the second B-battery unit to the post on the strip. Remember not to place the tubes in the sockets until the A and B-batteries have been connected. To save those who are unfamiliar with jacks any difficulty in wiring, it might be mentioned that the bottom lug on the detector jack is connected to the 22'4-volt terminal on the strip; the one immediately above this to the B-positive post on the transformer ; the next one above-to the plate post on the transformer, and the upper lug to the plate post on the tube and to the rotor plates of the condenser and one terminal of the coil. One lug on the horn jack is connected to the 90-volt terminal and the other to the plate post on the amplifier- tube socket. For best results, use an outdoor aerial consisting of one wire from 75 to 100 ft. long, and solder or clamp the ground lead to a cold-water or radiator pipe Examine ‘“‘Dead’’ Transmitting Tubes before Discarding Them Before consigning the “dead” tube to the waste basket, examine the wires in side of the stem leading from the termi nals. They may be burned off or have be come unsoldered, causing an open cit cuit. This often happens in transmitting tubes, and is easily remedied with a bit of wire and solder. A blueprint of this set, 1514 by 24 in. in size, will be sent to any reader upon receipt of 5 cents to cover the Address the Radio Dept., Room 514, Popular Mechanics Magazine 200 E. Ontario St., Chicago. a a al

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S60 Rheostat Permits Neat Mounting \ new rheostat designed to give a smooth vernier filament control has made its appearance on the market. This rheo- Rheostat of the Permits Neat Compact Graphite-Disk Type That Arrangement stat requires only one mounting hole, and can be inserted in the hole from which the old rheostat has been removed. It is claimed to be vernier all the way, with but one adjustment to make, and can be used for any tube, or combination of tubes. It is very compact. A particularly neat ar- rangement of the rheostat is shown in the upper drawing. Here the end of the rheostat is so close to the socket that it can be connected to the latter by means of id only about a le; in. long. Device Protects Tubes Designed tor use in the positive lead of the B-battery, a tube protector recently developed prevents damage if a negative lead of the b-battery becomes crossed with any of the other wiring of the set. The device is not a tuse, and the claim is made that it will not burn out. It also conserves the B-battery by limiting the current flow, yet allows ample current to pass to work the detector and amplifiers. @ THE 1-TUBE ULTRA-AUDION has proved an immense favorite. It was com- pletely described in our April, 1924, issue. Those of our readers who missed this, may obtain the issue by sending 25 cents to the Circulation Department. $62 POPULAR POPULAR MECHANICS Label Your Battery Leads It takes but a few minutes to make a set of little square or round cardboard labels for the A and B-battery leads, holes ing punched in the labels and the wires threaded through them, and the fan who has burned out a few tubes by accide: tally connecting the B-battery to the ment circuit will appreciate the tip. | those who want something a little mo pleasing to the eve than the cardbo labels the latter can be made of bra The labels should bear the name of the battery, the voltage and the polarity. Inspect Aerial and Ground before Summer An occasional inspection of the aeri and ground should be a religious duty « the owner of the receiving set, but espe cially after the last snow has disappeared Winter storms impose from the ground. a heavy strain on the aerial and mast and these should be gone over thoroug ly to see that they have not been dai aged, or the aerial accidentally ground There is also the danger that soldered co nections have become corroded during t] of alternate sun and rai and these should be looked to also. season snow, During the past year many radio-tul sockets have been cast aside for the n types appearing on the market, which ar guaran teed agai microphon action a othertul noises due vibration. the accot panyin sketch shown hi these discat ed oe © k ¢ may be claimed tf: further use and made just as free fr microphonic action as any of the ne types. All that is required to accompl! this is some hard sheet brass, appro mately 2-in. thick and of large enous area to allow a_ sufficient number clips to be cut from it, as shown in t! drawing. These clips are easily made any bench vise, and the cost is very sm MECHANICS - [-

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\ rILATING the photographic dark is not as easy a matter as venti- ny other sort of room, owing to that while a current of air is de- o light must be admitted. In many cial dark rooms, while satisfactory of excluding light are used, the tion situation is not so good, and upants, especially in the summer- en the temperature hovers around mark, are not to be envied. This igree condition, but one that reeable ~ a POPTITT apn WROCTTTFT ANT OOS All Shop Notes published in 1924, in book form—Fifty Cents—from our Book Department Ventilating the Dark Room By L. F. O'TOOLE remedied in the is fortunately easily majority of cases. The ventilator shown in the illustra- tions has been found very satisfactory in a case like this, as it excludes the light, but permits the air to be changed regu- larly. It is made of galvanized iron, set in a hole cut in the wail, and contains a series of blades so set that the air will work through it automatically. As shown in the sectional diagram, the casing is about 8 in. deep and 14 in. square; 1 in. Working Conditions in the Dark Room Will Be Improved Greatly When This Simple Ventilator Is Installed; Insert, Outside View of Ventilator eff

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S62 POPULAR MECHANICS from the outside edge a 9-in. sheet of gal- dark-room wall, while another similar one inized iron is soldered to the upper side is set on the opposite side of the room in of the box, on the inside, and 3 in, from a _ hole cut in the wall near the floor. A similar other arrar e ¢ sol ment that 1 dered to the be found sat oki a A factory, can, et yout course, | sine ame di used. The ¢ cut forced ort t the bottom through t 1 upper venti tor is replac« ( of the by air draw of the in through tl ectri¢ fan lower one ed wi the This lower ventilator is very essenti part of the stallation, as a complete! light - pro¢ dark roo! there are cracks that c be depends upon to leak the air nece sary to replace that blown « through t! upper venti! tor. Instead the lower vent a hole can cut through t dark-roo door, if desire and fitted w eted and sol sre } > adered to the ner side of e box as hown in the photo and dia cram, and the a | tinished Un der ordinary conditions a current ot ait ) nll work through the entilator as the warm air the room rise If forced adratt is ¢¢ red, the elec tric tam 1s placed in front of the ver vases On a 5 helt Sectional View of Ventilator, Showing Path of Air sheet — upported onangie and Position of Electric Fan trouver iron brackets, and sheet of bla s forces the foul air out effectively. cloth, tacked above the opening and One ventilator—the one provided with lowed to hang over the louvers, will all: the fan—is placed near the ceiling on the ventilation while excluding light. Spacing Nails on Boxes nails are 6-penny, or less. Increase spacing 4% in. tor each penny over Observations of packages which have No board should have less than two tailed in service and tests on packing at each nailing end. Space the ni boxes by the U. S. Forest Products Lab holding the top and bottom to the sid oratory have shown that the most com 6 in. or more apart, when the nails mon detect in box construction is inade 6-penny or less, increasing the spacing quate nailing. Attempts to strengthen in. for each penny over six. boxes bv the use of thicker lumber, with While such spacing may appear to out regard for nailing, very often only too close, it actually calls for only ab waste material two-thirds of the number required to | Nails holding boards to the end grain ance the strength of the nailed joints ot the box end should be spaced 134 in. the strength of the box in other respect ipart, and nails holding boards to the With the spacing given above, the nail ide grain ot the end, 2 in. apart, when is still the weakest point of the box 864 POPULAR MECHANICS

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one 1 in Any ize- nay tis- , of be air put he ila ced wn the ne yer Sa itial in- 5, in ely » oT »>m, no can ded k in Ces- lace out the tila d ol ent, be the om red with etal \ lack ‘ “el ig | » be bout bal wit! ects iling be - POPULAR MECHANICS 863 A Stain for Glass Windows Vindow staining, for privacy or other poses, can be quickly and cheaply e at home without calling in a pro- onal workman. The only materials uired are white shellac, dye of the red color, and waterproof varnish. ir a white window, which admits light, which is not transparent, coat the glass carefully with white shellac, dis- ed in alcohol. After the shellac is apply another coat, if necessary; after drying again, cover with the terproof varnish. Such a window can washed indefinitely without removing e stain, Colored windows are made by mix- ordinary cloth dyes into the shel- until the desired shade is attained. instance, for photographic dark- mM use, mix orange and crimson dyes to the shellac until it is very dark. Feeding Troughs for Poultry Customarily grocers, butchers and com- ion merchants feed and water fowls throwing handfuls of loose grain into crate and placing trays of water out- This method is, however, rather ectionable due to the muss caused by ittering grain and spilling water. A er method is shown in the drawing. Galvanized-iron troughs, which can be made by any tinsmith at a small expense, hooked on the slats of the crates as licated, one being used for water and HOOKS Troughs for Crates Are Convenient for Feeding and Watering Fowl the other for feed. They should extend along the entire side so that all the birds have an equal chance. Rollers Aid in Testing Tubes Experiencing some difficulty in testing large auto tubes, a Wisconsin vulcanizer constructed a pair of rollers and attached Wooden Rollers Attached - to Vulcanizer’s Water = ra — P Tank Facilitate Testing P , Tubes them to the water tank to hold the tubes submerged. Two wooden rollers, about 3 in. in diameter, are mounted on a frame and axles, which are made of heavy gal- vanized-iron wire. The ends of the wire are looped and passed through small holes in the rim of the tank to serve as hinges, and the projecting part of the wire on the other side of the rollers is bent to form a double hook that snaps over the rim on the opposite side of the tank. In use, the device is raised to allow the inflated tube to be put into the tank and the rollers are then put down. It is an easy matter to move the tube back and forth so that ev- ery portion may be observed under water, and the operator is not compelled to keep his hands in the water.—G. E. Hendrick- son, Argyle, Wis. Lubricating High-Speed Shafts The lubrication of high-speed shafts or bearings can be facilitated by treating the packing with a special lubricant. Take 2 oz. of gold, silver, aluminum or similar bronze powder and 6 oz. of ordinary cup grease. Mix these thoroughly and treat the packing with the resulting mixture be- fore it is put into the packing box. This lubricant, | have found, gives at least fifty per cent longer service than untreated grease.—James E. Noble, Toronto, Can. POPULAR MECHANICS 865

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864 Adjustable Footing for Ladder Painters, carpenters, tinsmiths and others whose trade necessitates the fre- quent use of a ladder, are often incon- Adjustable Footing for Ladder Permits It to Be Set Up Straight without Any Danger of S.invving venienced by the ladder slipping toward one side due to a slight slope in the ground. The usual remedy, which anyone naturally thinks of first, is to block up the ladder, but blocks are not alwavs handy. A de- tachable footing of the kind shown in the Dumpir POPULAR MECHANICS drawing is much more reliable, and as it is a small article it can readily be transported with the other equipment. It consists o a section of buggy-wheel rim, or any stout length of similarly curved wood. A slot is cut in each leg of the ladder to straddle the rim, and a short length of hardwood is fastened to it by means of a bolt and two strap-iron braces, as shown. The upper end of this stick is passed through a heavy iron ring, which is permanently kept or the lowest rung of the ladder. This ring is attached by splitting it and then spread. ing it, after which it is placed around the rung and bent back to its original shape A thumbscrew threaded through the side of the ring, is turned down to clamp the stick to the rung at any position. Bolts are put through the bottom of the ladder as shown in the detail, to prevent splitting and to retain the foot in position. The ladder can be set up straight, and after the screw is tightened, there will be no danger of slipping—G. E. Hendrickson, Argyle, Wis. Simple Method of Dumping Trucks A driver on a dump truck had the mis fortune to break the mechanism that dumped the load. However, he devised a simple method of dumping the load with out any help. When ready to dump he placed a 4 by 4-in. timber underneath the front edge of the body as indicated by the dotted lines in the drawing so that when the truck was driven ahead the body would be raised and the load dumped automati cally —Louis Latour, Plattsburg, N. Y. 1g a Heavy Truck with a wuetnn, Prop Set underneath the Front Edge of the Body, Which Is Raised by Driving the Truck Ahead

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j

POPULAR MECHANICS 865 Low Wagon for Silo Filling filling silos, or other work about m,. a low wagon is often conven fo convert the ordinary high wagon one of this type the reach is ed, and two 2 by 6-in. oak about 16 ft. long are fas- edgewise to the underside of rear axle, about 4 ft. apart. should be held in place with ts or wire. The forward ends next brought together, and a 6-in. plank, about 10 in. long, | between them. This shorter should have a hole drilled igh it so that it can be secured he underside of the front axle e kit ge bolt. \'-shaped frame, which will carry a one-ton load, takes ice of the reach. On it, and enough back so that the front eels will not interfere while ing, a platform, about 7 ft. constructed of planks. \ wagon of this type is so low that, en in use, the fodder may be loaded unloaded directly from the ground, without an extra man on top being essary, thus effecting a saving both in e and expense John T. Bartlett, ulder, Colo. } Boring-Bar Holder \ boring-bar holder for the lathe, which | hold all sizes of boring bars within its its, without bushings, is shown in the ustration. The head is machined to the ipe indicated and a hole is cut through is shown. The center part of the head be cut out if desired to eliminate the nger of having high spots inside and us permit a more accurate fit of the ring bar, besides reducing the weight of e hxture. Holes e drilled and ned 31 he cide TO SUIT ped in the cle -CENTER setscrews to /[ OFLATHE ghten the boring j on ir in the holder ! ¥ ra ‘ ~ Ne also through : ? " . ™ e base tor bolts to > ten the holder . the lathe bed 13° 3p. he height of the xture should, of course, be uch as to suit the height of the the centers above the bed. For erage work, a fixture made ac ording to the dimensions given in the ustration will prove satisfactory.

Handling Ford Driveshafts Ford driveshafts can be conveniently handled on the workbench by providing two brackets of the kind shown in the STUD FOR 8 STEEL PEENING UNIVERSAL- 4 JOINT RIVETS

BRACKET FOR ’ UNIVERSAL- JOINT END OF SHAFT

a sane, A) BRACKET FOR @| REAR-SLEEVE —__ = t OF HOUSING | fj | | ra) Y, th. -_ ni” a © ‘i is | | 2 a Brackets on Bench Aid Handling of Ford Driveshaft illustration. These are made ot 3¢-in. flat steel cut and bent to the shape indicated and bolted to the bench top. One bracket has a square hole to receive the universal joint end of the shaft and the other is cut to hold the rear sleeve of the housing Testing Machine Parts for Cracks Testing machine parts for cracks cat be accomplished very easily in the follow ing way: The surtace is first cleaned and then the suspected area is coated with mixture of whiting and water, mixed ti the consistency of a thin cream. After this coating ha dried the piece i vibrated by slight ~ 5 é tapping, which will 7 ORILL, STAR pps 32 iy »the er mao ft FOR cause the coating ti SETSCREW crack if there is 13 crack in the meta = ORILL a: Che whiting w ™ absorb enough oil ~i@ along the crack t re discolor it slightly at the edges, whicf will make the crac] r how up immed Ho < itely.—Sherwood |] ' Gq | {see Montpelier \----SIZE To FIT LATHE Idaho POPULAR MECHANICS R67

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VV VVVVVVVYV 2 | hein said Bill, the shop fore- “ man, “Old Hank is busy. Run over to the south shop at lunch time, and put a pulley on the lineshaft for that new grind- ‘er. The lineshaft speed is 200 r.p.m., and the countershaft should run at 450. Get a pulley from the store.” Johnny hesi- tated, but he was ashamed to let Bill know that he didn’t know what size of pulley he must get—in fact, he hadn't the slightest idea in the world how to figure it out. He went off to — the store and tried to bluff the storekeeper by asking for “the lineshaft pulley for that new grinder,” but, when the storekeeper asked, “What Sige 48 tt 5° Johnny was stumped again. j He scratched his head despair turned away from the store window, to meet the gaze of Bil l, who was regarding him quizzically. “What's the matter, Johnny? in and No pulley S in the store?” “Ves, sir,” said John, “b-but I don’t know what size I need.” “Never mind, boy,” said Bill, “that’s no crime; lots of older men than you don't know how to figure pulley sizes, but your real fault was in not confessing it at once. Get an 18-in. pulley and put it on, then comé over to my desk, and I'll fix you up so you'll never be stumped again.” “Figuring pulley sizes,’ explained Bill, when Johnny reported to him an hour 866 POPULAR later, “is a very simple matter—when yo know how. Now, that countershaft ha: to run at 450 r.p.m., as | told you, and th lineshaft runs at 200 r.p.m. The first thing to do is to measure the diameter o the pulley on the countershaft. That wa 8 in., wasn’t it? Now, we have all th: figures for a simple sum in proportio You know that the diameter of the line shaft pulley is the unknown, and that tl diameter of th: ©0248 t.¢ 1 shaft pulley the other sin lar term you have t ratio 8 : Ar .-swer. Now, t counters shaft is to ru faster than tl lineshaft, ther: fore the diat i eter of the u known pull will be tl! larger, and must arrans the other ter: of the prop: tion so that t! answer will | greater that So we state t! proportion |i] this—200 : 4 8 : Answe! thus putting the smaller number of re\ lutions as the first term, and the great: as the second term. Multiplying 450 8, and dividing the product by 200, we g« 18, the diameter, in inches, ofthe lin shaft pulley. “Now, if you will look closely at th problem, 200 : 450 8 : 18, you will se that the first and fourth terms are th numbers relating to the same pulley—th: one on the lineshaft; and that the secon and third terms also relate to the sam« “Run Over to the South Shop and Put a Pulley on the Lineshaft’’ MECHANICS

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POPULAR MECHANICS 867 —the one on the countershaft. This s us to form a very simple rule, which in apply to all pulley problems. The ‘t of the diameter and revolutions ne pulley equals the product of the di- ter and revolutions of the other. So we multiply together the diameter umber of revolutions per minute re- x to the pulley of which we know both, vide by the number, whether it is or diameter, that we know of the r pulley, the answer is the number we nt to know. That’s ‘what we did just We multiplied the r.p.m. and diam- r of the countershaft pulley, 450 and nd divided by the only number we had ing to the lineshaft pulley—200—and e answer was its other figure, the diam- Supposing, now, you knew that the ey on the lineshaft was 20 in. in diam- and the one on the countershaft was n. in diameter as before, but the line- iit runs at 250 r.p.m.; how would you ire the speed of the countershaft? Just hefore; multiply 20 by 250, the product 5,000. Divide this by the diameter of countershaft pulley—8—and the an- er is 625, the speed of the countershaft. Don't forget this simple rule. Multi- together the diameter and speed of ne pulley, and divide by the diameter or peed of the other. “But supposing you have a machine that is driven through a countershaft and you want to know the speed of the ma- chine spindle itself? You know the speed of the line and countershafts, and the di- meters of the pulleys on the lineshaft, countershaft, and the machine. Now, we ive two sets of driving pulleys, or driv- ers, and two sets of driven pulleys, or fol- uc LINE SHAFT 10 r 8” 6” PULLEY ——__ ON GRINDER} | | ; | | L_J COUNTERSHAF T FIG.t lowers. There is another very simple rule for this; multiply together the speed of the first driver and the diameters ot all the other drivers, and divide by the product of the diameters of the tollowers. Taking the sizes and speeds we used be fore, the lineshait speed is 200 r.p.m., the countershaft speed is 450 r.p.m., the line shaft pulley is 18 in. in diameter, the to lower on the countershaft 8 in., the driver on the countershaft 10 in., and the pul ley on the grinder, which is also a fo lower, 6 in. in diameter (see Fig. 1) Multiply 200 by 18 and by 10; the prod uct is 36,000; multiply 8 by 6, and divide this product into 36,000; the result is 750, and this is the speed of the machine. “A quicker way to do the calculation is to set the figures down in the form of a fraction, then some of them can be can celed out (example 1). Now 8 will divide into 200 and 6 into 18, so that we only have to multiply 25, 3 and 10 and this saves much figuring. If we knew the speed at which the grinder had to run LINE SHAFT -F—-—— .\\_ | 14° PULLEY \ \ 12” PULLEY \\ | Fig. 1 Illustrates the Problem of the Grinder and Its Drive and Fig. 2 How the Lathe Is Driven and the Speed Figured POPULAR MECHANICS 8693

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868 POPULAR MECHANICS

dag Porokacny eee.f- ‘a5: 4 °° © — wanted to find ROO X18 X 10_ 25 X 3X10 _ 750 pulley must be u out what size of 8 7. = A x & 1 on the motor? 17 pulley to put on it, EXAMPLE | pulley on the mot the process would

2% 1s to drive the 14 be the same, but in 200 X18 X1O_ 18 _¢ pulley on the lin: this case we would as shaft, and the 12 divide the product ad EXAMPLE 2 pulley on the li of the speed of the 8 7 shaft the 10-in. o first driver and the ' on the countershait diameter of all the are a 2 ae is = 35 Never mind tl! drivers by the prod- 3 6 usual open at

uct of the speed of EXAMPLE 3 the last follower

crossed belts. \\ have now the spe¢ and the diameter of the other followers. of the last follower, 200, and the diamete: Setting this down in the form of a frac- of the followers, 14 and 10; also the dian tion (example 2), we find the diameter _ eter of one driver, 12, and the speed of on to be 6. 750. We multiply the first three togethe “Supposing, again, that you are belting and divide the product by the product up a lathe to be driven from a motor toa _ the last two; the result is 3%, and if we lineshaft, then to a countershaft (Fig. make the pulley 3% in. in diameter we 2), and the countershaft must make 200 shall be very close to the proper speed r.p.m. The countershaft you have has a_ Stated again as a fraction, you see the cal- 10-in. pulley in addition to the cone pul- culation (example 3) is simple. leys and there is a 14-in. and a 12-in. pulley “Run along now, and tomorrow I'll sho on the lineshaft; the motor speed is 750 you how to figure gear sizes and speeds

RULES FOR CALCULATING THE SPEED AND SIZE OF PULLEYS The driving wheel is called the driver, and the driven wheel the driven or follower. R. p. m. indicates the number of revolutions per minute Problem 1.—The revolutions of driver and driven, and the diameter of the driven being given, require the diameter of the driver. RULE.—Multiply the diameter of the driven by its number of revolutions, and divide by the number of revolutions of the driver. Problem 2.—The diameter and revolutions of the driver being given, required the diameter driven to make a given number of revolutions in the same time RULE.—Miultiply the diameter of the driver by its number of revolutions, and divide the product by the given number of revolutions of the driven. Problem 3.—The diameter and number of reve being given, required the revolutions of the driven RULE.—Multiply the diameter of the driver by its number of revolutions, of the driven. Problem 4.—The diameter of the driver and driven, and the being given, required the number of revolutions of the driver RULE.—Multiply the diameter of the driven by its number of revolutions, and divide by the diam eter of the driver. lutions of the driver, with the diameter of the drive and divide by the diameter: number of revolutions of the driver

Storing Polishing Wheels attaching the supporting rod. In mounti: the two parts of the latter, one is broug When a number of polishing wheels are used, it is advisable to provide a suitable i method of storing them. Some shops use pegs on the wall for this purpose, hanging (COLLAR / a wheel on each peg, but a better method is to hang all of them on one support so devised that any one wheel can be re- moved cuickly. Such a support is shown in the illustration. It consists of two iron brackets, twisted and bent as shown and

POLISHIN — WHEEL

Pad COLLAR ~” - POLISHING _} attached to the wall, and an iron rod cut WHEELS in two on a slant at the center. A collar ud PINS-<--’ is fitted on each bracket end and held by FLAT-IRON BRACKET pins. A hole is drilled and tapped through Support for Holding Polishing Wheels Permits The: one of them and halfway into the other for to Be Removed Easily

870 POPULAR MECHANICS

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POPULAR against the flat bracket so that the col- ind rod form an immovable unit, while e other unit can be turned upward. Evi ently the slanting ends should’ bear rainst each other indicated in the rawing, and both halves should be long ugh to accommodate all the wheels to stored, or it would be imposstble to re- e the innermost one at either end. as Garage Patrons Indicate Service Desired by Cards In a garage where a large number of icks and pleasure cars were stored, pa- ns frequently found that their cars were given certain attention, such as wash filling of the gasoline tanks, and the iking of minor repairs. This work was : » be done overnight, and as many of the | ustomers were transients, a loss resulted to the garage owner. He, therefore, made a set of metal signs, painted in black d white, and indicating the kind of serv- e desired. These signs were kept near he garage door in a rack. The patrons laced the signs on their machines, and the ittendants gave the service desired with- out further orders.—L. E. Turner, Brigh- n, Mass. Inserting Valve-Spring Pins It is usually rather difficult to insert uto valve-spring pins, which keep the springs under proper compression. This due to the cramped quar- ters in which ‘it is necessary to hold the pin, and there is always dan- 1S ger of drop- ping the pin into the crankcase, from which it difficult to remove. A umber of connected pins can, however, © made from a length of stiff wire of the proper diameter, and can be inserted with- out danger of losing them, if the follow - ing method is used: Notches are filed in | the wire so that after the end 1s inserted through the hole in the stem, the wire an be broken off at the first notéh, leaving the pin in its place. If wire of the proper size is not available a long nail will give as good results—G. C. Douglas, Raleigh, N. C. 1S 1e: just POPUTLAR MECHANICS 869 Whitewashing Trees When trees in an orchard are white- looks much better to have the This washed it sprayed parts all of uniform height. Whitewashing Trunks of Trees to a Uniform Height Improves Appearance of Orchard can be done by using a strip of oilcloth, about 12 in. wide and long enougli to en- circle the largest trees. One end of the strip is tacked to the end of a pole as shown in the drawing, the pole being 2 ft. longer than the height of the part to be whitewashed. After the strip is wrapped around the tree a few turns, the sprayer can be used and there will be no ragged edge when finished. Removing Paint and Varnish The most efficient method of removing old paint and varnish is to burn the sur face with a painter's blowtorch. The heat causes the film to soften and it can then be scraped off easily. This method, how ever, can only be used on flat surfaces, and where a slight scorching of the wood ts not objectionable. A hot solution ot caustic soda (concentrated lye), l Ib. to the gallon of water, is also efficient. This should be applied with a fiber (not bristle) brush until the paint softens. This solu tion is very hard on the hands, and also raises the grain of the wood, and surfaces treated with it should be thoroughly washed and dried before repainting. MECHANICS is a) ~?

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wm ~? 870 © | ee a ee ee ss r- ID 5 ¢ ax p= - 1h \Ihfe \ |. \)SPRING i] Al *, PUMP ROD- 3 FE | 7 CONNECTING RODS GEAR BEARING _ SUPPORTS POPULAR MECHANICS to operate a deep-well pump. The wat: may all be collected in a single flume a: then directed to the acreage, or it may directed into separate ditches as show: In case four auxiliary pumps are used t! top of the plunger rod of the deep-w: pump must be squared arid the holes { the rivets offset or staggered so that t! Irrigation of Several Acres Carried On Economically with a Multiple-Pump Arrangement Run by One Engine Walking Beams Are Extended from the Plunger Rod of the Center Pump to the Auxiliary Pumps A Small Irrigation Plant Where water does not lie more than 20 ft. below the surface, the irrigation of sev- eral acres can be accomplished economi- cally by the method shown in the drawing. An ordinary pump jack is installed for per- manent service on the pump and a small gasoline engine provided to run it. By means of walking beams, arranged as shown in the drawing, it is an easy mat- ter to operate two or more smaller shal- low-well pumps at the same time. The drawing shows how this is done. To the top of the plunger rod projecting from the center pump are riveted the halves of two auto leaf springs; the longest and most flexible obtainable. These springs are fastened to walking beams by means of U-bolts, heated and formed in the spring eves. The walking beams are 8-ft. lengths of 2 by 6-in. material, pivoted in the center on wooden posts and being connected to iron-rod extensions on the plungers of the smaller pumps as shown. At all three bearing points on the walking beam the parts must be pivoted and free from binding. Ordinarily three pumps can be operated by the same engine used rivets will clear each ether—Dale R. V Horn, Walton, Nebr. Truing a Chuck Backplate A universal-lathe chuck was found t: be running considerably out of true and the trouble was found to be caused by th: backplate itself running off, perhaps di to the wearing of the threads or to slight sprin ing of tl spindle no As it was in practicable the time t make up new back plate, the ol one was fr STEEL-ROD PLUGS _) moved fro , the chuc UNTRUE BACKPLATE TURNED UP ‘ BEFORE DRILLING HOLES AND DRIVING PLUGS TRUED UP es Cue O RY OF CHUCK bo d y, int’ which 11 ‘ fitted tight! in a counterbored recess, and screwed tightly on the lathe nose after carefull cleaning the threads, collar, face and back plate boss to make sure there was no dirt POPULAR MECHANI(

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POPULAR chips to prevent the surfaces from rewing tightly together. The edge and nt face of the backplate were then trued by taking light cuts until the cut over the surface. Then six les were drilled radially into the edge of he plate and plugs made from steel rod ere driven in tightly until they bottomed. \n electrically driven toolpost grinder was en attached and the six projecting plug nds ground off while the backplate was evolving, until the chuck body was a drive it over them. It was then bolted on and und to run satisfactorily once more. howed all Threading Holes in Thin Plate [In sheet-metal ecessary to tap work it is frequently holes for attaching patches, brackets, nipples, lugs, or other fixtures. One then is met by the difficulty that the metal is too thin to permit cut- ting a good thread. The illustration hows three methods of overcoming this. By drilling the holes smaller than actually required and using a taper drift or punch to flare out the metal, as shown in Fig. 1, sufficient surface is provided for the tap- ping of a long thread. A patch can then readily be screwed down tight. Another ay of obtaining the same result at the edge of a sheet is to bend the metal over mce or twice as shown in Fig. 2. In cases here a still longer thread is required, a ole may be drilled for a small bushing, Simple Methods of Tapping Sheet Metal for Attachment of Patches or Fixtures FLANGE FOR 1 RIVETING ) ' one t « 1 Z t] Fic.2 Fig.3 et ll which is riveted to the plate as shown in k Fig. 3. The bushing is then drilled and irt tapped.—G. A. Luers, Washington, D. C. MECHANICS s 8) ~2 pent Substitute for Binding Pole Instead of carrying a cumbersome bind- ing pole when hauling hay or fodder, a Wisconsin farmer uses a cable and wind- CRANK AND WINDING DRUM Go. 7 LOCKING BAR a HOOKED TO BACK OF RACK | Rope and Winch Substituted for Cumbersome Binding Pole on Hayrack lass as a substitute. The rope is provided with a hook at each end and is securely attached, at its center, tothe winch. This is made from a length of gas pipe and is slipped through holes drilled in the front ladder of the wagon, a locking bar being also provided, as indicated, to keep the crank from turning after the rope has been drawn up tight. In use, the rope is brought over the load in the usual way, the hooks being fastened to the wagon frame at the rear, and the winch then used to tighten the rope over the load. Joining Roofing Sheets When copper and zinc-roofing come in contact with each other in the open atmosphere, there is a_ certain amount of electrolytic action and_ this starts corrosion. This can readily be prevented by coating the copper and zine with roofing cement or acid-proof paint before the metals are joined. Of course, the connection between@he two metals cannot be avoided entirely. Zine should never be used on a roof to be covered with red cedar or redwood shingles, as acid is formed when the shingles absorb moisture and this will soon ruin the metal —L. H. Georger, Buffalo, N. Y. rrma e¢

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a2 POPULAR MECHANICS = / REINFORCING ‘CLAMP \ CLOSE-UP VIEW OF STEERING ! ROD AND SWIVEL JOINT PIVOTED ON AXLE — a ; a " . CABLE ~ DOUBLE-ACTION t SPRING } 4- PULLEY —ak=\ “SO |" + cross BEAM ) ~ i — |? | REINFORCING a: PULLEY Cb) | PERO xg Lzlel} a am a — IRON ra] > TONGUE -- / __ BANDS | SWIVEL — Details of the Trailer Showing How the SHACKLE ARM Steering and Brakes Are Controlled and the Sulkies Carried — TRAILER POPULAR MECHANICS

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An Unusual Automobile Trailer By R. A. FRANKLIN ING rses last summer, those who had entered II 1 races at various Minnesota and adjoining states tered rting to find a considerable them from place to place on One owner, Mr. W. J. Way difficulty in Snellinger, to avoid these es, save freight, and be sure of the of his prized racer, Lou Randall. thod he used is applicable not only ilar situations, but mav be useful to ho must transport cattle or other often and purchased a used car, It upon the chassis 10 ft. DN i in safety. dismantled it, a comfortable in size and 3 ft. 6 in. in The upper photo in the illustra- vs the trailer al pl: this, j na as it appears when and the photo a view of the in- ice, its straw-stuffed gunny-sack the cleated gang- raised, forms the tail- top 1s 1n eht, below it] : it manger hich. when vo rout d ners of the g 1 se a TO] e 4 inew "all » hold the thil! re bored near so that, when passed through of the sulkies. The es ay be protect the horse from possible hile en route over rough roads. the sideboards and in front of ger is a shelf space that is exactly t size to hold the harness, blankets ther equipment necessary to the ess and to the comfort of the horse. en the storm top is needed, four ¢ made of | em and {;-in. flat iron, are bolted e side top rail, the canvas is thrown 1 , } asned in place by short Novel Wood Sled on Wheels 1 a novel wood siedad, vhich combines the tages of a sled and a cart, has been t by a west- farmer, uses it for ng wW ood hills and even ground, e it i difficult o with the linary wag- eS uipped with ivy iron run- in front | wheels just k of the cen- of the body. ey er Ss Ss rs cord loops. In pleasant weather the storm top is not used, and the horse is protected with a light fly blanket that covers him from head to tail. The method of attaching the trailer to the car is shown in the pen-and-ink draw ings. A heavy double-action spring is used over the iron coupling rod that tips the end of the tongue. When the cou pling pin is driven into place, a large cot ter pin prevents it from working out again. The steering has been provided for ingeniously by bending the shackle arm to such an extent that the steering rod may be turned parallel to the front axle and attached to the tongue through a swivel or link which is pivoted 5-ft. on the reinforced axle. Then, as the tongue moves with the car ahead, it auto matically turns the front wheels of the trailer as deftly as though it was steered by human hands. The trailer brakes are manipulated from the car driver’s seat by means of “6-in. wire cable attached to the brake controls and passed through a pul lev attached to the end of a single piece of cable. The brake cables are spread by means of pulleys fastened to a cross mem ber on the chassis. The single cable, with the pulley on the end, is passed from the trailer to the under the car body, and through the floor of the latter close to the emergency brake lever, where it handy for the driver. The front axle of the trailer was rein forced with flat iron, fastened to the axle with clamps rhe of the job wa about $100, besides the work of the Car®r, 1s cost ownel When running on the level or uphill, the wheels alone touch the ground, but when on a downgrade, the load causes the’ run ners to come into play also and no extra pressure falls upon the necks of the team. With this com bination cart and sledthe | farmer has been able to | handle twice | the quantity of wood that would be pos- sible with an ordinary sled. —Fred >. = ; ae _ Walker, Sui- Wood Cart with Runners and Wheels Carries Heavy Loads sun, Calif, POPULAR MECHANICS 875

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874 POPULAR MECHANICS Concrete Molds for Making to be made are available they can be u instead of the woode odels. When : Fender Tools id of the wooden models. W hen models have been withdrawn afte In many repair shops where lead ham- concrete has set, the insides of the m mers and other tools are used for straight- are given a coat of graphite, well bru ening bent and dented fenders, and other in, to prevent the lead from adhering them, suitable handles, made from CONCRETE _--,GRAPHITED are set into the molds, and the MOLDS

poured. A few of the tools that car made in this manner are shown in illustration.—G. A. Luers, Washingt District of Columbia Making Notations on Blueprints Quickly Blueprints can be marked with n tions such as “for approval,” “for mat: rial only,” etc., while they are being through the printing machine, by usi small pieces of tracing cloth with the 1 tations lettered on them, and runn these pieces through the machine o blank spaces on the large tracings. 1 will eliminate the necessity of stam each sheet separately and also make much neater blueprint—L. H. George: Buffalo, N. Y.

PIPE HANDLE BLOCKS A Concrete Mold That Enables the Repair Shop to Make Fender Tools Quickly and- Easily Portable Welding Outfit sheet work, the concrete molds shown in on Motorcycle the illustration will prove time and labor savers. The method of making these is a A New Orleans power company fr simple one. <A strong box of suitable quently had to answer emergency ca size is filled with a mixture of 1 part port- such as repairs to broken rails and bo: land cement to 2 parts sand, using a fairly ing, and this necessitated a portable we wet mix. The top is struck off level. and ing outfit. To meet this need a weld wooden models of the tools to be made outfit, with a 150-amp. generator, are set down into the concrete. The mod- mounted ona specially built sidecar fra: els should have a slight taper or draft so for a motorcycle, with extension leads t that they can he withdrawn from the con- . could be hooked up to the power line crete easily when it has set, and should be Emergency calls could then be handle greased before they are put in place. Of quickly and wit’: a minimum loss of ti: course, if similar tools to those that are —T. E. Dabney, New Orleans, La.

Welding Outfit Mourted on Motorcycle Sidecar Frame Enables Power Company to Care for Emergency alls Promptly S76 POPULAR MECHANICS

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POPULAR MECHANICS 875 No More Mislaid Tools ing charge of an auto-repair in which six men _ were ing, the writer found the lem of “keeping up with the a pressing one until the board shown in the illustra- as made and installed. The is constructed on one wall e shop, its size, of course, ending upon the number of be placed on it and the e available. It is made of 5 flooring painted some dark and allowed to dry. Then tools are held against the d and supported with nails en part way into the surface. outline of the tool is traced a pencil on the board, the removed and the outline in with white paint. requires some time to out- all the tools, but it is well ng th the trouble, as one can tell glance just what tools are ing when the shop is closed the night, and the time spent in tool ting is reduced by half. An ironclad requiring all tools to be replaced im- Foot-Operated Vulcanizer A Wisconsin tire-service man has elim- ited the troublesome necessity of using rew clamps on tubes when vulcanizing em by the evice shown the draw- It con- ists of a mple lever range- ent that - olds the vul- ey nizer tightly I n the tube, # ressure be- z) g applied by ra he foot and = the device 1 icked with a 7 itchet. In a Is Case an electric vul- 2S anizer was SS d: 2 = —S sed; it 1s fastened to a | ever made of 4% by 1%-in. flat iron, piv- ted at one end to the bench top. An iron nvil of 44-in. material is screwed to the POPULAR Tools in Use or Missing Are Indicated at a Glance with the Use of This Board, Which Saves Much Time in the Shop mediately after use is in force, and the men soon learned to observe it strictly.— F. B. Howell, Mendenhall, Miss. bench top to project over the edge the end being directly under the vulcanizer. A %- in. iron rod, with a coil spring attached, is pivoted to the press arm and the spring hooked to the foot lever, which is also made of 4 by 1%-in. flat iron. The op erator can adjust the pressure of the vul canizer by means of the pedal and the device is locked against a ratchet screwed to the floor so that the edge of the foot lever will engage any of the notches. In use, the tube is placed on the anvil, and the vulcanizer locked down on it. When the cure is completed, a slight kick against the pedal releases it so that the tube can be removed. A Good Drying Oil To \% gal. of water add 1 Ib. of sugar of lead (poison—lead acetate). Shake occa sionally, and when the lead is dissolved add 2 qt. of water; then filter the solu- tion and add 3 gal. of raw linseed oil. Stir in 1 lb. of powdered litharge, shake it often and then let it stand for several days. The oil found on top will be the drying oil, and it must be poured off into another vessel. The liquid is clear and bright and dries in about 24 hours. MECHANICS Cr ~? ~?

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S76 Safety Basin for Washing Small Machine Parts in Gasoline In almost every garage or repair shop a pan of gasoline is kept on the work- bench for the washing of small machine Novel Wash Pan for Cleaning Small Ma- chine Parts in Gaso- line ee AIR VALVE parts. Such a practice is not only waste- ful but also dangerous, especially where the work room is accessible to the public. A much better arrangement, and one that will meet with the approval of the insur- ance inspector, is shown herewith. POPULAR MECHANICS A 3-ft. length of 1%-in. gaspipe is serted through the center opening of a gal. gasoline can and soldered securely place, so that the lower end of the pipe about 1 in. above the bottom of the ca Four braces are also soldered or weld onto the pipe and to the top of the ga line can to strengthen the device. A flo flange is screwed to the upper end of t pipe and a basin soldered to this, a hok being punched through the bottom of the basin to receive a stopper. A valve fro an inner tube is soldered in the top of t can as shown, and an air-tight cap, pr vided with a metal wing, is screwed the spout. In use, a tire pump is attached to th: valve and after three gallons gasoline have been poured into the ca through the basin funnel, opening the ca on the spout to let out air and then closing it again, air is pumped into the can, for ing the liquid to rise into the basin. The cork stopper is then inserted in the ope: ing in the basin to retain the gasolin while the machine parts are washed. B removing the cork and loosening the c on the spout, the air is allowed to e cape from the can and this permits t gasoline to flow back into the can. Ii solution of washing powder. dissolved hot water is poured into the basin oc« sionally, the grease and foreign matte the gasoline will be made to settle to the bottom of the can, and a clear liquid w result. Once a week, or so, the clear liqu should be drawn off and the can cleane out thoroughly. two or Overcoming Dredging Difficulties By A. W. BURG gravel was contfronted with the getting the 10-in. suction dredge line under the track cable of the slack-line excavator without hindering the operation of either dredge or excava- tor. The pumping dredge moved the sand and gravel from the bank to a point under the track cable of the excavator, which dug the material again and conveyed it to the hopper of the screening plant. Ordinarily a 30-it. suctron pipe was used, handled by a mast and boom on the end of a boat. Power for raising the suc tion pipe was furnished by a hoist belted to the main engine. In order to dig under the track line while it was in operation, a framework was built on two pontoons and superintendent of a large A® company, | problem ot 7“R POPT TAR Mi 4 arranged so that the pipe could be rai and lowered between the two. As dredging continued forward, more pij. was added to the suction and dischars pipes and more pontoons placed under pipe to support it. - Flexible-hose conne tions were used where the suction pi was connected to the pump and at the fi joint back of the submerged part oi t suction pipe. Enough pipe was added this way until a bay had been formed the further side of the track line, the b being large enough so that the dreds could be moved there without interferi with the operation of the cable. The float ing extension to the suction pipe w then discarded, and operations continu: with the short suction pipe. aT AWE s'e

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POPULAR MECHANICS 8 ~? ~> Cc S Hopper, with Mast ns t arry uc- Pipe; Track e Shown in Up- per Part of Photo a be f P = Screening Plant and Receiving Arrangement o on- = i | | General View of the Plant; the rack Cable for the Excavator Is Shown at the Right Crossing the Suction Pipe Carried on the Pon- ons, and at the Left the Dis- charge Pipe Is Also Carried on ntoons to a Point beside the Track Cable: Below, the Dis- harge Pipe, Throwing Material Front of the Excavator Bucket -

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POPULAR Moving Signs for Small Stores much sta- windows attention In attract Moving signs more tionary ones. For this rea- son dealer, are than ? ? apt to a Novel Moving Signs on Sewing and ash- ing Machines Attract Attention to Window Display displaying wash- ing and machines, placed an endless - belt sign be tween the rollers the wringer, and a simi lar one under the needle of the sewing machine. The machines were put in op eration and this caused the signs to move around continuously.—Charles Abbot Goddard, Los Angeles, Calif. sewing of Precautions in Painting Do not use any paints containing com- pounds of lead about stables or outbuild- ings where the fumes from decaying or ganic matter are present, as these gases are likely to darken the lead paints. Do not use with lead paints any pigments that may liberate compounds of sulphur; for example, ultramarine blue, which contains sulphur in a form in which it may be set free. is a beautiful and very permanent blue, and may be used with zine white, but it should not be used with white lead or any other lead pigments. Prussian blue, on the other hand, does not contain sul- phur, and may be used with lead pigments. Remember that turpentine and benzine are very inflammable; hence special pre- cautions should be taken not to bring paints containing these substances near an open fire. Many pigments are poison- ous, and the workman should be careful to remove all paint stains from the skin, ‘ie DrsYDI’ Tr a wD MECHANICS and not under any circumstances all, paint to get into his mouth. O should not eat in the clothes in which has been painting, and should always particular to wash the hands thoroug before eating. It is not advisable to u any turpentine or benzine to remove pai: stains trom the hands, but rather to thoroughly with linseed oil or, in fa any fatty oil; then, by washing the har well with soap and water the paint m be removed, provided it has not been lowed to dry too hard on the skin. Treatment for Mildewed Burlap When burlap wainscoting becom: damp it mildews. The dust of this m be brushed off with a stiff bristle brus after which a size made in the follo ing way is applied: Dissolve 4 oz. of pu verized alum in 1 gal. of hot water, 4 bluestone (poison) in 1 pt. of hot wate 2 oz. white glue in 2 qt. of water, and oz. sugar of lead (poison) in 1 qt of wate Make these solutions separately and the mix them together, the bluestone soluti: last. Apply with a broad brush and let dry.—A. A. Kelly, Malvern, Pa. Wheeled Hog Swiller On the tarm where hogs are kept swiller of the kind shown in the photo w be found very handy, as it can be read pushed around and its contents quick! dumped into the feeding troughs. It coy sists of an old steel oil drum with t! top cut o mounted wheels. wheels we! taken from ; the handle were cut fi! Wheeled Hog Swiller Lightens Farm Chores the tongue and the frame was also tak: from the same implement. Tem Pab ? Roa € alr] old cultivator: e

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Prize Offers and Announcements $150—Best New Uses for Stop Watch two awards of $100 and $50; also ten additional s of one stop watch each. These offers are made the best lists of uses for the Pastor stop watch, h is an accurate instrument consisting of a time- nd a stop watch in one. The larger one of the ffers will he paid for the best list, the smaller r the second best and a Pastor stop watch, valued will be given for each of the next ten best es of uses received. Each use should be stated efly and simply and numbered according to its place e list. Write on one side of the paper only, with and address on each sheet. y 4. wad all replies dustrial Award, Sterling Watch Company, 15 East ty-Sixth Street, New Vork, N. Y. Offer closes 1, 1925. $1,000—Article to Increase Brass Uses With the person who designs some acceptable article which is composed of considerable brass in the form of eet, rod or tubing, and which can be protected by tent, or with anyone who develops an acceptable plan ere brass can be successfully and usefully substi- ted for a competing material now used in established ) es of commerce, the Bridgeport Brass Company enter into an agreement to pay royalties on the of such an invention, plan or suggestion, up to ) The Bridgeport Brass Company will be the e and final judge in reaching a decision regarding the mmercial value of the invention, plan or suggestion, e} ; t if the company approves and enters into such an vreement in any imstance, and reward is paid up to an O veregate of $1,000, payments shall then cease and the lgeport Brass Company shall become proprietor of rights, privileges and returns from the promotion, iiacture or sale of any such patent, plan or sug- the Bridgeport Brass Company adopts under offer. May 1, 1925, is closing date for this offer. ress Bridgeport Brass Company, Bridgeport, Conn. $1,000—Adjustable Miter Box e sum of $1,000 in cash and a satisfactory royalty | be paid by Roche and Moore for a suitable miter x for carpenters, to be employed with the ordinary ndsaw. The design must be such that it can be easily | quickly adjusted to any arc of a half circle. It = hould be one inexpensive to manufacture, should be ght in weight and pares planned to be con- he tructed of either wood or steel. No models of sug- pes sted designs should be submitted until after the wings or sketches have been sent to the donor. This yn neern reserves the right to be the sole judge of the he erits of all ideas submitted and their availability for loption by our organization Address Roche and e, Cochranton, Pa. This offer expires May 1, 1925. $100—Galvanized Steel Garage Design e The sum of $100 in cash and royalties over a period years will be paid to the person submitting to this or a_ satisfactory design for a _ galvanized-steel irage. It must be of simple construction and yet be ifficiently strong to withstand windstorms and snow ads on the roof. The design must be original and patentable. All matter submitted will be passed upon olely by the donor. Address, John B. Berger, P. O. Box 792, Baltimore, Md. Offer closes May 1, 1925. $200—Electric Sign Controls The Acme Electrical company will pay the sum of re Mi $200 in cash for the drawings of controls for an elec * tric flashing sign. The sign is to consist of not less han 300 lamps The controls are to operate so that separate advertisements can be shown in rotation metal or wood letters are to be used. The adver- sing matter is to be composed from the bank of 300 imps. This concern will reserve the right to reject y or all plans offered, and guarantees the return of all those not accepted, postage prepaid. This offer expires May 1, 1925. Address, Acme _ Electrical (Blackpool) Co., Richmond Chambers, 106B, Church Street, Blackpool, England. $250—Pulley-Using Machine The Standard Pulley and Manufacturing Company is in search of some sort of machine on which cast-iron pulleys would be the principal item and which would have a demand that cou'd justify its manufacture by this concern in fairly large quantities. We will pay the sum of $250 in cash to anyone who submits a sug gestion for such machine, provided the suggestion 1s accepted and used by this company. This organization will act as sole judge of any and all ideas submitted to it. Address, the Standard Pulley and Manufacturing Company, Cincinnati, Ohio. This offer expires May 1, 1925. PREVIOUSLY ANNOUNCED ALL OFFERS CLOSE MAY 1, 1925 FOR SKYROCKET STICK HARMLESS IN descent, $1,000; bombshell with illuminated flag, $250; chemical combinations to produce smokeless fireworks colors, $250. Thearle-Duffield Fireworks Company. MOTOR-OPERATED HANDSAW FOR MANU facture and sales; award, $10,000 in royalties. R. L Barker and Company. ELECTRIC HEATING ELEMENT WHICH will operate and interchange with base and cover of Imperial self-heating gasoline iron, $500. Imperial Brass Company. TO ANYONE WHO WILL PRODUCE FOR them a saxophone reed to satisfactorily replace the present reed, the Buescher. Band Instrument Company will pay the sum of $1,000. THE PHENIX RADIO CORPORATION WILL pay the sum of $1,000 for the design of a new form of condenser for radio reception. FOR A SATISFACTORY HAMMER - BLOW arrangement for portable hammer drill, the Wodack Electric Tool Corporation will pay $500. THE SUM OF $25 WILL BE PAID BY CELLO Products, Inc., for suggested new uses for its prod uct. Information from the concern on request $2,000 WILL BE PAID BY THE NORTH Shore Food Products Company for a method of pro cessing or preserving cottage cheese to keep it fresh for at least two weeks. FOR THE BEST SUGGESTED IMPROVE ment on a gasoline-heated blowtorch and soldering nd branding iron combined an award of $500 will be paid by the Everhot Manufacturing Company TO THE PERSON SUBMITTING TO THEM an article which they can make in their machine and electrical shop, the Guyan Machine Shops will pay $250 over and above its royalties or sales price GRANITE STATE MOWING MACHINE COM. pany offers $500 in cash and royalties for satisfactory working drawings for gasoline-motor lawn mower they accept for manufacture and marketing AWARDS OF $500 EACH WILL BE PAID for a waterproofing process for a library paste and a method that will produce increased sales of this prod uct. John J. Harris and Company THE SUM OF $50 on OFFERED BY THE Parsons Manufacturing Company for the best plan they receive for uses a ground slate. . Full Details Regarding the Previous Offers Listed Above, May Be Obtained by Ad- dressing the Bureau of Information, Popular Mechanics Magazine 879

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880 POPU LAR MECHANICS Radio Questions and Answers Q. I have a five-tube neutrodyne receiver, and I am told that I should have my tubes matched.

Is this eaeaeiares A. Many sets that have three or more tubes w we better if the tubes are changed from one soc ket to another All tubes of the same type are supposed to have the same amplification factor; this, however, is not always true Tube matching is very simple if y ire equipped with or have access to the proper instruments, and many dealers will do this for you when 1 buy the tubes It is of value to have matched tubes in the radio-frequency stages. Q. What size wire is best to use in wiring a radio receiver? Should I use insulated wire or bare wire? N ; .

se ‘ 14 tinned-copper wire Use “spaghetti” tubi f u wish, but insulation is only necessary where the wires run close together Always keep the grid nd plate leads as far ipart as possible Q. What size rheostat should I use with a UV-199 tube? I am making a one-tube Ultra-Audion receiver like the one you described in the April, 1924, issue. \ rheostat was recommended in ‘the ar will find it listed in the material list You 35-ohm rheostat if you wish he 40-ohm ticle. ¥ can use a Q. I live in the country and do not wish to erect an aerial mast. There is a large tree in the yard that I could use to support the far end of the aerial. Is this a good plan or must I put up a mast? A. A tree will inswer the purpose, but cer up for the loss? If so, how should I connect them? A. This is not advisable, as the B-battery should be discarded when it drops below 18 volts. Below this voltage the. battery becomes noisy, and adds resistance to the plate circuit. Q. Is it better to buy small B-batteries and renew them often, or to buy the larger type? . tubes. It will be necessar me to watch the water level Radio Editor, I opular Mechanics for you to use a_ verniet in the various cells. I no- tice one cell drops much quicker than the others. What is the reason for this, Magazine, 200 Chicago.

rheostat on the detecto tube as the filament « trol will be more critical Use a 6-ohm rheostat for E. Ontario St.,

and what must I do? A. Evidently the hard rub ber jar mtaining the plates in this cell is cracked, and permits the solution to escape. There is nothing that you can do except replace the cracked container } We would advise that you place the battery in the | hands of your local battery-repairman at once Q. I have a quantity of aluminum wire, can I use this for an aerial? A. Aluminum wire is not recommended for aerials. Use No. 14 copper wire or a good grade of stranded antenna wire, plain or enameled Q. Will one step of audio-frequency amplification give me sufficient volume to operate a loud speaker? A. One step will not give much volume with the average re ceiver on a loud speaker. It is the second step that has the greatest Be mong However, on local stations one step may prove satisfactory Q. I have two old B-batteries. These indicate about 12 volts each. Can I add these old batteries to my new ones as the voltage in the latter drops to make the detector tube and two 25-ohm_ rheostats for the UV-201A tubes. You can also use a higher plate voltage on the standard tubes. We would advise fr 67 to 90 volts for the B-battery. Q. I am having trouble with my B-batteries; they run down very quickly. I recently bought some new Lubes not of standard make. Since using these tubes I have had to renew my B-battery twice. Could it be possible that these tubes use more current? A. This is pro! ably the case. Defective tubes draw more plate cu rent than their rating. Some “bootleg’’ tubes draw fr two to three times more current than standard tul Better stick to standard tubes. Q. I am having trouble with my three-coil honeycomb regenerative set. The circuit is correct but the signals have no volume. What can I do to get more volume A. Your trouble may be that the connections to the tickler coil are reversed. It is also possible that t tickler coil may not be large enough; to find out, t a 35-turn coil.

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 all appearance of doing so, we are obliged to omit the name of the maker or seller of any article described. on file and will be furnished free, by addressing Bureau of Information, Chicago. [Editor.] This information, however, is kept Popular Mechanics Magazine,