Popular Science Monthly 1924-08: Vol 105 Iss 2

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Pop AUGUST, 1924; Vol. 105, No.2 25 cents a Copy; $2.50 a Year ular Science Monthl Most Wonderfully Illustrated Magazine in the World Published in New York City at 225 West Thirty-ninth Street Coming Next Month Can Science feed you and me? Can chemistry supplant Nature’s intricate processes of growing life, making us independent of crop failure and banishing forever the fear of hunger and famine? In PoputarR ScrENcE MonTHiy next month Ellwood Hendrick, Sc.D., nationally famous chemist and author, will tell you what our chemical laboratories are doing to solve the world food problem. A new era of sport, with the sky as a playground and the earth as the grandstand, is one of the fascinating promises of recent progress in aeronautics. Witness the Air Circus with its “jumping balloons,” “‘dirigible tag,’ and other exciting but harmless fun among the clouds, which actually arrived this summer. In another of his delightful forward-looking articles, Lieut.-Comm. Fitzhugh Green, U.S. N., discusses the trend of aeronautics into the field of safe and sane sports. Have you a cold? Do you know that a sure, safe, and easy cure for it has been discovered by the Chemical Warfare Service of the Army in the use of chlorine, the poison gas employed as a weapon of war? No doubt you have read of this discovery and have wondered just how effective it is. The truth about the chlorine treatment and its important results will be told next month. Mechanical tricks of the ‘‘grifter’’—the cunning gamester who pockets your money in games of “‘chance and skill’ at the traveling carnival—will be confessed and explained by a retired showman. You'll be interested in learning why it’s so hard to knock down the canvas-covered cat and win a prize. And more than 200 other fascinating articles and pictures giving you all the news of science and invention, together with practical ideas for radio, the automobile, the home, the home workshop, and the use of tools and machinery. Brigadier - General Ames A. Fries (left), chief of the Chemical Warfare Service, U. S. Army, and Lieut.-Col. H. L. Gilchrist, chief of the Medical Di- vision, demon- strating the ap- paratus used in the new chlorine gas cure for colds POPULAR SCIENCE MONTHLY iomned monthly. Single copy, 25 cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foreign countries, Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post Office Department, Canada. Printed in U. S. A. Copyright, 1924, by the Modern Publishing Co. The contents of this magazine must not be reprinted without permission. In presenting in its editorial columns numerous stories of new products of applied science, POPULAR SCIENCE MONTHLY does not underwrite the business methods of the individuals or concerns producing them. The use of PopuLAR SCIENCE MONTHLY articles, or quotations from them for stock-selling schemes is never authorized. H. J. . eet R. C. Wilson, Vice-President oO. Capen, Secretary and Treasurer In This Issue Page A Wonder House of Science........ 21 By Raymond J. Brown Nature’s Super-Power Plant........ 24 By George M. Ocgle A Survivor from the Age of Reptiles 33, 36 Could We Decode Mars Messages?.. 27 By Lieut-Comm. Fitzhugh Green Noveltiesin Radio................. 29 The Swiftest Traveler on Earth.... 30 By Fritz Blocki Telepathy Put to the Test......... 32 By Robert H. Gault, Ph.D. pT ee ee 33 By Frederic M. Delano, Jr. Why You Make Errors os oo. oo SO By Donald A. Laird, Ph.D. Dewdrops Display the Sider’ sArt.. 37 The Future of the Helicopter. 38 In the Vanguard of Science......... 40 Double-Locking the Door.......... 42 A-Sikyecraper Garage... ............ 4? Holder for Telephone Receiver...... 42 Steel Pipe Foundations. 43 The Greatest Irrigation Project... 43 An Automatic Policeman. 43 Model ‘‘Health Street.” 44 Champion Barrel Builder.......... 44 Fighting Tank Directed by Radio... 44 Odd Motor Caravan Carries Canoe... 45 Garage in Hollow Tree Trunk.......° 45 Shipping a Mammoth Gun......... 45 Card Index for Radio Tuning....... 46 Two-Way Loop Aerial............. 45 Liquid Resistance Grid Leak....... 46 Thirteen-Tube Relay Set........... 47 Tubes Are Visible in New Receiver.. 47 Six Headphones from One Set....... 47 Mysterious Fire in Roadway. . 48 Gage for Balloon Tires. .. 48 Excavating Shovel Swims to Work.. 48 Airplanes Paint the Sky............ 49 New Tip for Cutting Torch. cai ee Rule for Inside Measurements...... 49 Could You Save a Drowning Man?.. 50 By Clifford Thorne New Inventions for the Housewife... 51 An Automatic Schoolteacher........ 52 Fourteen Instruments in One....... 52 Motorized Tailor Shop............. 52 Huge Subway Model in Court...... 53 Sedan-Locomotive Runs on Tracks.. 53 Ancient Boats Ferry Automobile.... 53 World’s Largest Arch Bridge....... 54 The Highest Irrigation Dam........ 54 Giant Amphibian Airplane..... 54 Five Cars Carry Huge Pipe. 55 Chained Fountain Pen. 55 Auto Tows Itself out of Mud........ 55 Compact Auto-Camping Outfit. 56 BROW WORE NCOP osc ck ce ce cs 56 Automatic Shoe Laces............. 56 Safety Tile Prevents Slipping. era A Light Paper Raincoat............ 57 How Much Science Do You Know?.. 57 Baker Is Expert Fish Breeder....... 58 Soundproof Typewriter Cover...... 58 New Folding Umbrella............ 58 New Lumber-Cutting Process. 59 Saw Grip for Paint Brush... Succ Gas Tank Extension for Filling sc 59 ‘Fossils’? Challenge Evolution 69 Ripples of Sand and of Metal. . 60 Microphoto Camera Attachment 60 Operation Reproduced on Screen. . 61 New Telephone Conveniences 61 Saving Money in Home Building. . 62 By Maurice 1. Flagg ihe Last Word in Badio........... 64 By Jack Binns Building a five-Tube Loop Set...... 66 By Joseph Calcaterra Efficiency Tests for Motorists....... 67 By Fred A. Moss What Does Your Car Need?....... 69 Solving Balloon Tire Problems.... 70 The Home Workshop...... 71 Better Shop Methods...... 76 And other timely articles and pictures

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Pop AUGUST, 1924; Vol. 105, No.2 25 cents a Copy; $2.50 a Year ular Science Monthl Most Wonderfully Illustrated Magazine in the World Published in New York City at 225 West Thirty-ninth Street Coming Next Month Can Science feed you and me? Can chemistry supplant Nature’s intricate processes of growing life, making us independent of crop failure and banishing forever the fear of hunger and famine? In PoputarR ScrENcE MonTHiy next month Ellwood Hendrick, Sc.D., nationally famous chemist and author, will tell you what our chemical laboratories are doing to solve the world food problem. A new era of sport, with the sky as a playground and the earth as the grandstand, is one of the fascinating promises of recent progress in aeronautics. Witness the Air Circus with its “jumping balloons,” “‘dirigible tag,’ and other exciting but harmless fun among the clouds, which actually arrived this summer. In another of his delightful forward-looking articles, Lieut.-Comm. Fitzhugh Green, U.S. N., discusses the trend of aeronautics into the field of safe and sane sports. Have you a cold? Do you know that a sure, safe, and easy cure for it has been discovered by the Chemical Warfare Service of the Army in the use of chlorine, the poison gas employed as a weapon of war? No doubt you have read of this discovery and have wondered just how effective it is. The truth about the chlorine treatment and its important results will be told next month. Mechanical tricks of the ‘‘grifter’’—the cunning gamester who pockets your money in games of “‘chance and skill’ at the traveling carnival—will be confessed and explained by a retired showman. You'll be interested in learning why it’s so hard to knock down the canvas-covered cat and win a prize. And more than 200 other fascinating articles and pictures giving you all the news of science and invention, together with practical ideas for radio, the automobile, the home, the home workshop, and the use of tools and machinery. Brigadier - General Ames A. Fries (left), chief of the Chemical Warfare Service, U. S. Army, and Lieut.-Col. H. L. Gilchrist, chief of the Medical Di- vision, demon- strating the ap- paratus used in the new chlorine gas cure for colds POPULAR SCIENCE MONTHLY iomned monthly. Single copy, 25 cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foreign countries, Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post Office Department, Canada. Printed in U. S. A. Copyright, 1924, by the Modern Publishing Co. The contents of this magazine must not be reprinted without permission. In presenting in its editorial columns numerous stories of new products of applied science, POPULAR SCIENCE MONTHLY does not underwrite the business methods of the individuals or concerns producing them. The use of PopuLAR SCIENCE MONTHLY articles, or quotations from them for stock-selling schemes is never authorized. H. J. . eet R. C. Wilson, Vice-President oO. Capen, Secretary and Treasurer In This Issue Page A Wonder House of Science........ 21 By Raymond J. Brown Nature’s Super-Power Plant........ 24 By George M. Ocgle A Survivor from the Age of Reptiles 33, 36 Could We Decode Mars Messages?.. 27 By Lieut-Comm. Fitzhugh Green Noveltiesin Radio................. 29 The Swiftest Traveler on Earth.... 30 By Fritz Blocki Telepathy Put to the Test......... 32 By Robert H. Gault, Ph.D. pT ee ee 33 By Frederic M. Delano, Jr. Why You Make Errors os oo. oo SO By Donald A. Laird, Ph.D. Dewdrops Display the Sider’ sArt.. 37 The Future of the Helicopter. 38 In the Vanguard of Science......... 40 Double-Locking the Door.......... 42 A-Sikyecraper Garage... ............ 4? Holder for Telephone Receiver...... 42 Steel Pipe Foundations. 43 The Greatest Irrigation Project... 43 An Automatic Policeman. 43 Model ‘‘Health Street.” 44 Champion Barrel Builder.......... 44 Fighting Tank Directed by Radio... 44 Odd Motor Caravan Carries Canoe... 45 Garage in Hollow Tree Trunk.......° 45 Shipping a Mammoth Gun......... 45 Card Index for Radio Tuning....... 46 Two-Way Loop Aerial............. 45 Liquid Resistance Grid Leak....... 46 Thirteen-Tube Relay Set........... 47 Tubes Are Visible in New Receiver.. 47 Six Headphones from One Set....... 47 Mysterious Fire in Roadway. . 48 Gage for Balloon Tires. .. 48 Excavating Shovel Swims to Work.. 48 Airplanes Paint the Sky............ 49 New Tip for Cutting Torch. cai ee Rule for Inside Measurements...... 49 Could You Save a Drowning Man?.. 50 By Clifford Thorne New Inventions for the Housewife... 51 An Automatic Schoolteacher........ 52 Fourteen Instruments in One....... 52 Motorized Tailor Shop............. 52 Huge Subway Model in Court...... 53 Sedan-Locomotive Runs on Tracks.. 53 Ancient Boats Ferry Automobile.... 53 World’s Largest Arch Bridge....... 54 The Highest Irrigation Dam........ 54 Giant Amphibian Airplane..... 54 Five Cars Carry Huge Pipe. 55 Chained Fountain Pen. 55 Auto Tows Itself out of Mud........ 55 Compact Auto-Camping Outfit. 56 BROW WORE NCOP osc ck ce ce cs 56 Automatic Shoe Laces............. 56 Safety Tile Prevents Slipping. era A Light Paper Raincoat............ 57 How Much Science Do You Know?.. 57 Baker Is Expert Fish Breeder....... 58 Soundproof Typewriter Cover...... 58 New Folding Umbrella............ 58 New Lumber-Cutting Process. 59 Saw Grip for Paint Brush... Succ Gas Tank Extension for Filling sc 59 ‘Fossils’? Challenge Evolution 69 Ripples of Sand and of Metal. . 60 Microphoto Camera Attachment 60 Operation Reproduced on Screen. . 61 New Telephone Conveniences 61 Saving Money in Home Building. . 62 By Maurice 1. Flagg ihe Last Word in Badio........... 64 By Jack Binns Building a five-Tube Loop Set...... 66 By Joseph Calcaterra Efficiency Tests for Motorists....... 67 By Fred A. Moss What Does Your Car Need?....... 69 Solving Balloon Tire Problems.... 70 The Home Workshop...... 71 Better Shop Methods...... 76 And other timely articles and pictures

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wm 66 69 79 POPULAR SCIENCE MONTHLY If You Want | Bigger Pay zi: FREE TEST There’s a sure way to increase your earning power. And here is such an opportunity. Look into it—you may recognize it as your one chance to earn the biggest money of your life. RE you ready for a shock? Then, let me tell vou that if you have average intelligence and can read and write, there is a quick and easy way for you to double or triple your present salary—to earn enough money to satisfy any average ambition. And after reading this offer, if you do not quickly make more money, you have no one to blame but yourself. Don’t take my word for it. By a simple free test one you can make in the privacy of your home—you will know that every word I say is his $75 a month job for one which pays him $500 a month. O.H. Malfroot, of Boston, Mass., stepped into a $10,000 position as a SALES MANAGER—so thorough is this training. All these successes are due to this easy, fascinating and rapid way to master certain invincible secrets of selling. These men were formerly clerks, bookkeepers, factory workers, farm hands, mechanics, machinists, chauffeurs, firemen, motormen, conductors, etc. Their success proves that previous experience or training has nothing true—or otherwise. The test does not obligate you or cost you one penny. But make it! Then judge for yourself. It has proved to be THE opportunity for thousands. They have found the way to bigger pay—are now earning from five to twenty times as much as formerly. And the beauty of it is they enjoy every minute in the day’s work. They are their own bosses. A Field of Unlimited Opportunities State of 11linoie} a County of Cook 9 ~~ . I, J. B. Greenslade, President of the National Salesmen's Training Assocoia« tion, of Chicago, Illinois, state under oath, that between January ist, and June 30th, 1925, thie Association received oalle for 29,256 Salesman. to do with success in the selling field. It proves that any man who wants to, and who is willing to put in a few hours of spare time each week, can quickly get a selling position and make big money. And they started with this free test. Why don’t you make this free test and prove, to your own satis- faction, that a bigger salary is easy to get? The test is contained in a free book, ‘‘Modern Salesmanship,”’ which we will gladly send you with- out obligation. After reading the book through you will ask yourself The thousands who have made this test before you, and who are now making the money you would like to make, are now salesmen. Ninety-five per cent. once thought they were not ‘‘cut out for selling,’”’ that sales- men were ‘‘born” and not made. They found it was a fallacy that had kept them in the rut. They discovered that any one with proper training can sell, and they are making from $5,000 to $10,000 a year because they had the vision to recognize opportunity. Are trained salesmen in demand? afidavit on this page. Look at the Thousands Have Proved It For instance, Ellis Sumner Cook, 58 Superior St., Oak Park, Ill., left a $25 a week job and last year made $9,000! H. D. Miller, a Chicago boy, was making $100 a month as a stenographer in July, 1922. In September, 3 months later, he was making $100 a week asa salesman. W. P. Clenny, of Kansas City, Mo., stepped from a $150 a month clerkship into a selling Job at $500 a month. He is making $850 a month now. M. V. Stephens, of Albany, Ky., was making $25 a week. He took up this training and now makes five times that much. J. H. Cash, of Atlanta, Ga., exchanged the questions it brings up. The answers will show you whether you can get away from the humdrum, small-pay job for the lucrative and fascinating work of selling. Make This Free Test at Once a Don’t turn this page until you have {iia clipped the coupon, filled it out, and sent it on its way. It may mean the turning- point in your life. Write now while the impulse to succeed is upon you. NATIONAL SALESMEN’S TRAINING ASSOCIATION 53 W. Jackson Blvd., Dept. 15-K, ALES MATIONAL cne TRAINING ASSOCIATION nA me omen # a RES Chicago, Illinois eee ee SS ES SS ES ES GD SD Tcaans Salesmen’s Training Association | 53 W. Jackson Blvd., Dept. 15-K, Chicago, Illinois | Gentlemen: I will accept a copy of ‘‘Modern Salesmanship”’ with the | understanding that it is sent to me entirely free. | INDIE K voccicccd oe cece ee diees cesses eesee eed eee ee See eneenee Cosme eRemew | RAABOES.....d.ccccccccec veces ccs de cbccvesacecevece seeesbee se teekemnstarm

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Mis . % )} { @ AUTOMOBILES AND ACC ESSCRIES rATENTS—Write for our Guide Books and “Record of Invention Blank” before disclosing inventions. Send model or sketch ot your invention for our free Examina- tion and Instructions. Terms reasonable. See ad- vertisement on page 105. Victor J. Evans & Co., 189 Ninth, Washington, D. C. AUTOMOBILE Parts— Used parts for most any car at half factory list prices. Allen, Briscoe, Buick, gq Chalmers, Chevrolet, Dodge, Dort, Grant, Hudson, Hu mobile, Oakland, Overland, Olismobile, Reo,S Studebaker and many others. Send list of parts wanted. Maxwell Bros., 4105 Olive Street, St. Louis, Missouri. $1.25 BUYS a positive Headlight Tell-tale. Rpecialty Co., Somerville, Mass SPORT Speedster and racing bodies for Fords; build Handy to order. Build your own Bucket Seat speedster. Send $1.00 for blue prints, instructions, and life size per patterns, complete; Keller Auto Body Co., Inc., Dept. 24, 317 W. Winkler Ave., Louisville, Ky. NO Car is Modern unless having the Auto-Lavatory that keeps motorists clean. Instant Service Soap and Water. Automobile Show Sensation. Special Demon- strator Price. Distributors Wanted. Emmons Manu- facturing Co., Canton, Ohio. MONEY!—Silvering autolights, radiators, mirrors. Refinishing tableware, stoves, brass beds, etc. Outfits, Methods free. Write— Sprinkie-Plater, Dept. 96, Marion, Indiana, WHAT do you need? We have it. Gray's Auto Parts Company, 3212 Brighton Road, Pittsburgh, Pennsylvania. M. P. LAUGHLIN—Patents-Engineer-Attorney-Spe- cializing Power-Automotive Inventions. 47 West 42nd St.. New York. CLEAN your ear for 5c. Dri-Klean-It removes —_— dirt, dust. No soap or water. Agents wanted. Wri Amer. Accessories Co., Dryclean 279, Cincinnati, Ohio BUY a Gas Gun fer $2.50 and avoid stopping on the read because out of gas. Handy Specialty Co., Somer- ville, Mass. AVOID “turning turtle,” leaving the road, locking over center. You can stecr safely and easily out of ruts, through mud, sand, snow and on center-crowned roads, with a Sprague Worm Steering Gear on your Ford. Same type as used on all larger cars. Prevents bumps in road from_turni front wheels aside; gives you control of steering. A absorbs shock, vibration and strain on arms and shoulders. Makes a far better and safer car. Easily, quickly installed; no holes to bore; outlasts car. Guaranteed to satisfy you. Write for particulars. Sprague ‘Tire Co., Dept. 2, Omaha, Neb. FORD ACCESSORIES SPEEDSTER fans—see **Red-i-Kut” ad. page 110. MOTORCYCLES, BICYCLES, SUPPLIES OVERSTOCKED—200 Used Motorcycles. ust be soki at once. We have Harley-Davidsons, Indians, Ifendersons, Excelsiors, Clevelands. Prices $25.00 Up. Write for our Bargain List. Myerow Seether, Dept. C, 15 Berkeley St., Boston, Mass. DON’T buy a bicycle motor attachment until you get our catalogue and prices. Shaw Mfg. Co., Dept. 4, Galesburg, Kansas. USED parts for all motorcycles cheap. Schuck Cycle ‘o., 1922 Westlake, Seattle, Wash. MOTORCYCLE sidecars—Bargain prices on experi- mental and discountinued models. Write Flxible Co., 337 Water Street, Loudonville. Ohio. MODELS AND MODEL SUPPLIES HULIT & Co., 625 Jaekson, Chicago, Ills. mental Machinists. Model Makers. Dies. Complete general Machine shop. Ex-Lameon. WE make working models for inventors and experi- mental work, and carry a complete stock of brass gears and model supplies. Send for catalogue. The Pierce Model Works, Tinley Park. Illinois. EXPERT Model Making, modern equipment, reason- able prices. American Patents Corporation, 635 F St., Woshineton, D.C. MOTORS, ENGINES AND MACHINERY MOTORS— Manufacturer's Surplus Sale. KHP, $8.50; ISHP, $32.50; 1 HP, $54.50. 8 Volt Charging Generators, Experi- Patterns. $8.50. Complete Lighting Plants—Generators—Light Machinery. Write for Catalog. Motor Specialties Co., Crafton, Penna. BIJUR Generators, brand new, 6 volts, maximum output 22 amperes at 2000 r. p. m. Government paid $45.00 each, our price $10.00. General Sales Company, 1921 S. Michigan Avenue, Chicago, Illinois. CONCRETE Building Block Machines and Catalogue free. Concrete Manufacturing Co., Third St., St. Louis, Mo MANUFACTURING PATENTED Articles, Models, Brass Work, Machine Construction; Dies Made. 3aum’s Metal Specialties, Kansxs City, Mo DIES, Tools and General Manufacturing. Models and manufacturing of new inventions our specialty. Logan Machine Co., 126 S. Clinton St., Chicago, Tl DEVELOPING ideas and manufacturing our Absolute satisfaction. 33 years’ experience; write & B. Die al Specialty Co., 2018 Elm S8St., Cine innati. Ohio. Dept. Gaee TS BUY CASH for old gold, silver, platinum, ints. Prompt payment. N. Dearborn, Chicago. Molds 307 So. epe- teeth, magneto Mail to N. Ubler Co., 117 POPULAR SCIENCE MONTHLY y we Opportunities for Popular Science Readers Another $25.00 IN PRIZES To win one of these cash prizes is easy, and every reader is invited to enter this fascineting competition. Just write a letter of not over seventy words answering this question: — What Advertisement of “Money Making Opportunities” in this issue interests you most and why? Here are the prizes we will pay for the ten best letters answering the above question: — First Prize. ... - $10.00 Second Prize ...... 5.00 Tees Pelee ww we eo s BED And 7 Prizes of $1.00each ...... 7.00 First read every one of the ‘““Money Mak- int Opportunity” advertisements on pages four to seventeen. Check the ones that interest you. Then read over the ones you have checked and decide on the one that interests you most. men write a short letter, not more than seventy words, telling us why the advertise- ment you pick interests you most. Remem- bet that ten prizes will be awarded. You have a good chance of winning one of them. Be sure to mail us your answer before August Ist. The prizes will be awarded, in the order of their merit, for the letters that are most interesting and best expressed. The names of all the prize winners and the letters that win the first two prizes will be printed in this column in the October issue. Address your prize letter to Contest Editor POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City Last Month’s Prize Winners The First Prize of $10.00 goes to William S. Little, Rochester, New York, for his letter on the advertisement of ‘‘Money Making Oppor- tunities.’”” Here is Mr. Little’s letter:— Dear Sir: Your own ad interests me most:—‘*‘Money Making Opportunities.”’ It increases the advertising value of every ad listed under it by making it worth while for thousands, who otherwise might not read one ad, to read all. And the more who read ads, the more responses to them—the more responses, the more advertising business for Popular Science! Last but not least the chance to make ‘‘ten bucks,”’ interests wall You ruly, WILLIAM ‘5. LITTLE. H. L. Rozzele, Chattanooga, Tennessee, wins the Second Prize for the following letter regarding the advertisement of the R. J. Carnes Company. Here is Mr. Rozzele’s letter :— Dear Sir: Having read every one of the advertise- ments in the ‘‘Money Making Oppor- tunities,’’ I find I am interested most in the small advertisement of R. J. Carnes, because I enjoy typing authors’ manuscripts; for one not only earns ‘‘spending money,” but also gets the pleasure of reading some fine stories before they appear in the maga- zines for the public. Very truly, H. L. ROZZELE. The Third Prize goes to Fred Even Central Avenue, Dubuque, Iowa. The winners of the other seven prizes are:— Mrs. J. W. Grubbs, St. Louis, Mo.; Vernon L. Baldwin, Durham, New York; Bertha Mundy, Marietta, Minn.; William F. Sand- mann, 4 olis, Ind.; Adele M. Nolin, Astoria, L. WY VY. elrose, St. John, y x heat G. Davis, Harrisonburg, Va. 2525 Rate 25 Cents a Word. Advertisements in. tended for the October issue should be received by Aug. 5th. RADIO AND SUPPLIES RADIO sets: Super-Heterodynes, Neutrouynes and other standard types all makes; guaranteed; 50c off list. Why pay more? Send for bulletin 245 Radio Icxchange, 925 Broadway, New York. RECHARGE your worn out “B"” Formula and Instructions 50c postpa. Company, O-we-go, N. Y. RADIO Tubes repaired and exchanged; write for free Battery for lc. id. Monarch Sales circular, *‘How oe = 4 Away with Storage Batteries on All Tubes.” C. . Radio Tube Works, Essex Court, Newark, N. J. RADIO Generators: 500v 100 watt, $28.50. Battery Charging Generators, $8.50. High Speed Motors. Motor [ senerator Sets all sizes. Motor Specialties Co., Crafton, enna. 2,650 MILES Distance with one tube. Any Novice understands our Simplified Instructions, including Panel Liyout and ae, 25e. Vesco Radio Co., Box PS 117, Oakland, Calif RADIO tubes, Dil, Di2, UV199, UV200, i oe $1.25. Dutch radio tubes, D12, D300, D201A, $2.5 Crystal set, 50c. Add postage. ' Radio Sales Co., 1 io North Kingshighway, St. Louis, Mo. WHY Not Reach Out with your crystal set? There's music on your aerial every night from stations far away! I have shown page ce bad people how to hear long dis- tance programs without tubes. Write me today. Leon Lambert, 670 South Volutal 2, Wichita, Kansas. FOR THE HOME HOME weaving—looms only "39.90. weaving rugs, fa Big money in rtieres, etc., at home from rags and waste materia feavers are rushed with ordeig. Send for free loom book, it tells all about the weaving business and our wonderful $9.90 and other looms. U nion Loom Works, 482 Factory St., Boonville, New York. GRANDFATHER clock works $5.00. Build your own case, instructions free; make good profits selling your friends. Clock works with chimes for old or new cases, Write for full particulars. Clock Co., Nicetown, Penn. GASOLINE lamps, lanterns and heaters. Catalog free. Little Wonder Mfg. Co., Terre Haute, Indiana. KIDDY Kabinet—Ornamental, fascinating, useful, instructive. Actual size patterns. Instructions, 25 50c, coin. Guaranteed satisfaction. Bogrens Kiddy Kobinets, 2651-8th Ave.. New York. TRADE AND TECHNICAL SCHOOLS EARN SLO to $20 per day. Learn sign painting, Auto painting, decorating, paperhanging. Be an expert in a few weeks—Low cost—Actual work— No books—Cataloz Free. Chicago Painting School, 157 West Austin Avenue, Chicago. CHICAGO Technical College offers short, interscy practical courses in rafting and Engincering— civil, mechanical, electrical, structural— Architecture, Building Construction, Plan Reading, ete. Courses fitted to your . No time wasted. Instructors are experts. Grad- uates in demand at big salaries. Opportunities for part- time work while studying. Day and evening classes. 21st year. Enter any time. No special preliminary training required. Low tuition—easy terms. Write for 52-page illustrated Blue Book, describing opportunities — n to our graduates. C *hicago Technical College, 23 Chicago Tech. Building, Chicago. BE a Bricklayer. Attend a school operated by Building Contractors. Three Months Day Course $75.00. ated Building Employers, 128 A. B. E. Rapids, Mich. Associ- Building, Grand AVIATION THE American School of Aviation announces a new correspondence course in mechanics of aviation. A thorough training in practical aeronautics, America) School “ot Aviation, Dept. 674-B, 3601 Michigan Ave. Chicago, Illinois. BOYS get a three foot model aeroplane free. Nothing to sell. Write to Aero Shop, 3050 Hurlbut Ave., Detroit, Michigan. WANTED TYPISTS— Earn $25-$100 es in spare time copy- ing authors’ manuscripts. Write R. J. Carnes, P-1, Talla- poosa, Georgia, for particulars. OLD gold, silver and platinum for cash. oratories, 222 Market St., Newark, N. J. WANTED: Light Machinery, Lathes, Drill Presses. Model High Speed Gasoline and Steam Motors. Bcst Cash Prices Paid. Motor Specialties Co.. Cratton, Penna. DETECTIVES needed everywhere. Experience un- necessary. Particulars free. Write, George Wagner former Government Detective. 1968P Broadway, N. FORMULAS FORMULA Catalog tree. C. A. Lutz, Apartment 241, York, Pennsylvania. “YOUMAN'S GUIDE” contains best 5,000 formulss and recipes for every trade, business, oc*upation, house- wife. Let this book make you money Money-back guarantee. Paper cover $1.25, Cloth $2.00. Post-paid. Circular, book catalog free. Wells and Edwards, De partment M, 852 George, Chicago. RARE Formulas. One dollar each. Any purpose. American Formula Service, 928 Fourth National Bank Building. Nashville. Tennessee. ADDING MACHINES FREE trial, marvelous free adding machine. ( subtracts, multiplies, divides, automatically. Work equals $350.00 machine. Price only $15.00. Speedy, durable, handsome. Five-year guarantee. Used by largest ‘corporations. Write today for catalog and free trial offer. Lightning Calculator Co., Dept. O, Grand Rapids. Michigan. More Money Making Opportunities on pages 6 to 17 Penn Lab- Adds,

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POPULAR SCIENCE MONTHLY 5 hears Electric Earn’70 to"200a

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irom rags 5 eeneans Men like you are needed right now in the fasci- _ nating Big Pay Field of Electricity. Never before was there your own such a demand for men at such high salaries. Get into this a vot big pay game now. Get a real job doing work you will like. wn, Penn. I have made it easy for you to earn $70.00 to $200.00 a ame free. week. Yes Sir—$3,500.00 to $10,000.00 a year—and I'll help you get just the job you want ‘and back it all up with a

z, useful, : Eee signed money back guarantee bond. ns Kiddy do what I said—quickly fit LS —— at Home you to earn $70 to $200 a ting, Auto Ea mane xpert n'a — Look What =| Wee—83,500 to $10,000 a —Catalo $12 to $30 a Da year—as an Electrical Ex- Avent ¥. | These Men Ar is 60 di in Avenue, eon des: anne endl ese men © pert. My Course is so differ- ——— ai 4 be ~ intersdy ; Re é ent from ordinary courses ~~ — a are making Earning that it has revolutionized d to your money—big money—money : home study training. There rts, Grad that outclasses all other J J. R. eten of Delawarey 1 is nothing else anywhere af 8 for par . lio, earns from $30. fe f . sei Say, eT patmate ve | acute, | ear Mail Coupon Now . . pleting my course. He use It is the simplest, easiest to pvr fr a few short months you can ff to carn $5.00 a day asa 1 understand ne yet the most With my book I will send you alsoa College, 23 be an Electrical Expert earn- | Scice. a $3500 a week | thorough ' and complete Proof lesson, a credit check for $45.50, my yy Builaine ie a hes gs * =. mechanic of Chehalis, Wash. § Course of electrical training ONC? back guarantee bond—a whole . Associ- y made almost i le st : ts ae sear 1 will do this for you right [| mad ee cee ——- in the Country today. With packet of interesting, money making facts. —EEE nees a new ation. A America) higan Ave., . Nothing e., Detroit,

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in your own home and in your spare time. Follow my sim- plified, easy to understand method and you will quickly learn to fill any one of the many big jobs that are con- tinually open to trained men. Other Men Like You Are It. . You Can Do It Last year 4280 of my students and graduates re- ported better jobs and pay increases. The names of some of them are in the panel directly above. These men all earn from $60.00 to $200.00 a week and they are the happiest and most pros- perous bunch of men you ever saw. You might call it luck if one ora dozen of them jumped from little ‘ four’ jobs into the big pay class but when thousands have done it you know positively that my training alone was responsible and that it will do the same for you. Lack of Experience or Education Is No Handicap If you have the average man’s intelligence and can read and write, I can . quently

a town where he didn’t think he could earn a dime. Harold Hastings of Somers, Mass., only 21 years old, cleans up $480.00 a month. He was still in high school when he started on my course. Joe Cullari, 523 N. Clinton Ave., Trenton, New Jersey, increased his income 300% in one year and fre- makes the - entire cost of his course back - one day’s time. G. Sigety, 901 Standard Life Bldg., Pittsburgh, Pa., only 19 years old, jumped from $10.00 a week to $60.00 a week with his studies only half finished. Herbert Dick- erson on a farm near Warren- ton, Virginia, made $7,- 500.00 last year applying the electrical training gave him to farm work.

‘two by it, any ambitious man, re- gardless of age, lack of edu- cation or experience, can quickly become a big success in the wonderful, fast grow- ing field of electricity. Electrical Outfit and Tools—Free Awhole Outfit free. Everything you need —tools, instruments, material and a real workable motor. With this Outfit you do practical work right on the jump. You don’t have to buy a single thing—I give it all to you free because a good working outfit is neces- sary and I want my students to have the best. Send for My Free Book —the Vital Facts I want every ambitious man in the United States to have this free book. I want them to see just what a big, magnificent thing the Electrical Industry is. Send for your copy now and learn what. wonderful opportunities are before you this very minute and how they are increas- ing year after year.

Mail the coupon now while the desire for success is upon you. Mail it andthen decide if you want to stick ona small pay, no-fu- ture job or be a $3,500 to $10,000.00 a year Electrical Expert. Now. ’ L, L. COOKE, Chief Engineer Chicago Engineering Works 2150 Lawrence Ave., Chicago Dept, 3-C Trained Man . ERiCe eit LL. COOKE, Chief Engineer i Pay Man Chicago Engineering Works : Depts3-C 2150 Lawrence Ave., Q CHICAGO containing Sample Lessons, your Big Book, and full particulars of your Free Outfit and Home Study Course that will fit me for a $3,500 to $10,000 a year electrical job. Send this fully prepaid, without obligation Dear Sir:—Send at once the “Vital Facts” j on my part. | OCCU PAC ORs s. 66:5 sce ssansereincrengens ee ae | a ae <: 3 o a

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‘Good Bye, Boys!” “To-day I dropped in for a last word with the boys at the office. And as I saw Tom and Dave there at the same old desk it came to me suddenly that they had been there just so the day I came with the firm four years ago. “When I started here I was put at a desk and given certain routine things to do. But after a few months I began to realize that I was nothing but a human machine and that I couldn’t expect to ad- vance that way. “So I wrote to Scranton and arranged for a spare-time study course that would give me special training for our work. Why, do you know, it gave me a whole new interest in our business? In a few months I was given more responsibility and more money. Since then I’ve had three increases, six months ago I was put in charge of my department, and now my big chance has come—lI’m to be manager of our Western branch at $5000 a year! It just shows what spare-time training will do.” If you want to make more money, show your employer you're trying to be worth more money. If you want a bigger job, show him you're willing to prepare for it. There’s a simple, easy way to do it. For 32 years the International Correspondence Schools have been training men and women right in their own homes whenever they had a little time to spare. Thousands of men and women have stepped up in just this way. More than 180,000 are studying now. Ten thousand are starting every month. Can you afford to let another price- less hour pass without finding out what the I. C. S. can do for you? Here is all we ask—without cost, without obli- gation, mark and mail this coupon. Mail the Coupon To-day! ewe ew eee oe ee a ee a cee oe a ae ae aa ep INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7601-D, Seranton, Penna. Without cost or obligation on my part, please tell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Business Management [1] Salesmanship Industrial Management [_} Advertising () Personnel Organization |} Better Letters () Traffic Management [ ] Show Card Lettering () Business Law [|] Stenography and Typing (JBanking and Banking Law |] Business English {Jj Accountancy (including C.P.A.) LJ Civil Service (J Nicholson Cost Accounting Railway Mail Clerk

(]Bookkeeping Common School Subjects (j Private Secretary ] High School Subjects Spanish O) French Lj Dilustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering Architect Electric Lighting Architects’ Blue Prints () Mechanical Engineer Contractor and Builder (J Mechanical Draftsman Architectural Draftsman (0 Machine Shop Practice () Concrete Builder C)Railroad Positions ( Structural Engineer ()Gas Engine Operating Chemistry 1) Pharmacy {)Civil Engineer Automobile Work os oe Mepping, Airplane Engines a 14 ic "@ ¢ >, Sones Masteneeing (i Medio (J Agriculture and Poultry

(J Mathematics Rees seven Street 3-6°24 RN Ua dap Caves cnc gisdacs baisccces oizpbsxubbaues constecausovecbe vceapeavpeuvseee EES ee RID 5 cscs screccttcicmssemiacatuenad . Occupation Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal. Canada

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Money Making Opportunities EDUCASIONAL AND INSTRUCTION DOUBLE entry bookkeeping mastered in 60 hours; guaranteed; diploma. International Bookkeeping In- stitute, Springfield, Missouri, Desk 10. LINCOLN-JEFFERSON University. Home Study in Academy College, Theological, Law, Music, Pharmacy. Business and Graduate schools, leading to degrees. Box G, Capitol Building. Chicago. USED correspondence courses bought and sold. Bar- gain catalogue 1000 courses free. Students’ Exchange, Dept. 3, 47 West 42d Street, New York. BOOKKEEPING in a week, $1 postpaid. 1859 Walton, Ave., New York. MATHEMATICS and Drafting taught by mail. Courses in Arithmetic, Algebra, Geometry, Mensura- tion, Trigonometry, Logarithms, Mechanics, Mechanical Drafting, and Tool Designing. Harding School, Box H. Highland Park, Mich. VISUALIZE! Correct method of self-study. Dollar brings book. Jewett, No. 3 Englewood Ave., Brookline, Massachusetts.

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FOPULAR SCIENCE MONTHLY Spare Time Reading Teaches Profitable Trade—Solves Problems . Over a hundred million dollars worth of building is be- Condensed Contents of Audel’s New Guides er Fl ing done every month! The biggest building boom in the Guide No. 1—Over 431 pages—1200 illustrations rgest and pp history of the country. Menthat know carpentry are in great demand. 1 oo tel the different kinds —How to make a work bench. as ine i The quickest way to learn carpentry and get your share pf the build- | —How to use the different kinds ~~ /!0W to make a mitre box. a ing money is by spare time reading of Audel’s Guides. Learn the = ——. me : ‘ Bae og make a mitre shooting F: fundamentals, then keep the volume you need handy as a practical | ~Gomplcte detailed information ae in Radio working guide. Carpenters everywhere will tell you that Audel’s | —How circular and band saws are ~!!0W to plumb and level work in Radio, | New Guides are a Good Set. voy ll —How to use the chalk line. i ‘ —How to use the steel square. ais . ae . amd of re I M M t Ss t Cc t —How to sharpen tools. How to lay out work. aa a — How to file and sct saws. — How to use rules and scales. New Ideas odern Methods -Short Cuts eee ee ee ek. on — . This course ‘‘Audel’s Guides for Carpenters short cuts, time and labor saving suggestions, 7 ata tools, with over 900 illustrations and Builders” consists of 4 handy volumes of new ways that cover the entire theory and | —How to build furniture. showing specifically how. over 1500 pages with thoroughly illustrated | practice of the subject illustrated by sketches Guide No. 2—Over 485 pages—400 illustrations charts, diagrams, graphs, pictures with calcu- and forms all specific and practical. Audel’s | —ypyow to understand carpe tena: Mow tian thes lations for every job from making the excava- er Sagres: ager een, sel @ OnGerst carpenters ow to jroportion beams. d } i ine building. ¥. Guides give you the short cut, professional arithmetic. — How to use dra wing instruments en 20 CORMTELIEE SEE CHS DUDES. * na information you want. No need to guess or | —!1ow to understand geometry. —How to read plans. will find these new Guides most complete an take chances. Every day you have before you —How to understand trigonome- —How to survey. comprehensive in addition to being both time- : ae ene melee. ina de try. —How to draw up specifications ly and practical. There are 3700 actual ex- in this set the exact, practical, useful informa- —How to solve mensuration prob- —How to estimate cost. amples of efficient construction work with new tion that will help you with every job that lems, ; —How to build houses, methods, ideas, solutions, plans, systems, comes up in your daily work. oe the strength of garages, bungalows, etc. id 4 Cc 9 B F 2 d Guide No. 3—Over 255 pages—400 illustrations Thousands Say Gui es re arpenter Ss est rien BB to excavate foundations. —How to attach lath to cornes 2 ee -1 —Hlow to build foundations. posts. **Reasonable for ready reference. {foreman or super- | figure out the next { professional like | s a acd ta : ~ : i a ah ns rice”’ The arrangement | intendent who can} day's work. —G.]| myself who is try- oo bs —— bbarars bdr it How to “os temporary and 6 ‘ of subjects and the | aftord to be with- | M. McJohnston, ing to build him- Trey na build beled orb ‘f claire ith perso {ribband I find the Guides simple way it is]}out this valuable | R. R.1, Hammond, ] self a home at the to bui orms for con- -—Howtoframe girts and ribbands very | satisfactory. | I ined ke | work. I wish you | Ind least expense — crete. r ‘ — How to set window frames. The knowledge in the Cacke were ae pe pena : Otto F. Schulze, | —!ow to proportion foundation —How to frame partitions. them is much great- | ~* ; oa ; orb ee, 3° footings. —How to distinguish various i z bs 3 : S “a t. Lil —How to frame houses. _ types of roofs. = Kr. Le rules ae . — ——- ThaGuides have West mont, Ill. —How to set girders and sills. —How to use the settings 12, 13 or rd are hee ad City, N ma soe met with my com- —How to frame joists. and 17 on the steel square. ancy tor be ae oe nem plete satisfaction. —How to construct a well hole. —How to lay out mitre cuts. ti tg rs a8 oss Anyone expecting —How to frame a studding. —How to use tangents, and full penter should pos- eee 'N or TS] *Guides Save | to build a home can —How to frame corner posts. detailed information covering sess a set. —Ralph oint, N. J. Hard Knocks’”’ well save $150 or —How to lay out and cut braces. sky lights, scaffold and hoisting. = aaa Low- **Good For The Guides are | jnron by. cane: the Guide No. 4—Over 448 pages—400 illustrations ell, Mass. Professional Seats PRACT eee ee —How to put on wood, fibre and —How to build stairs Carpenters”’ ’ : in your books. Ww. rhe : ’ v § 3. irgest Vetuablot and should be in| }:. Frantz, Box 77, metal shingles. an aren to fais A ad It is the most]|the hands of all | Tysc; a Ohi : —Ilow to lay gravel roofs. ae a in the Beginners or uscarawas, io. : 3 ao Old Timers”’ handy reference | young carpenters is —How to lay tin roofs. —How to lay floors. aini work that I ever | as well as a lot of “GC 7 —How to hang doors. —How to put on interior trim. ing, I have looked | came in contact | the older heads. If ee — How to frame windows, yay juCcCcess, over my Audel | with. It isthe very | I had such infor- : —How to put on siding. —How to paint. n each Guides and find a] thing that the|mation 20 years The books are —How to put on exterior trim. —How to give first aid to the wealth of informa- |} building mechanic | ago they would | surely worth more ——How to do cornice work, injured. rs over tion. (heir size | needs every day | have saved meJ|than the purchase gene oe sc aed a ee $4 PER MONTH-ENTIRE SET & en and Pe hac put im ther there is not a nights trying to = to the non- asl ’ FREE EXAMINA TION School kit and have them : yy Be fs; — - 4 ree ie \ , POCKET SIZE-FLEXIBLE COVERS leading bf fe We 1600 PAGES-3700 ILLUSTRATIONS t Meyer em tell AS cents in a P ys ' k telling ‘4 ; j , oe ; “ans ‘ ‘ 4 4 i # Leer f ; 4 TY | — ) Auvers} AuvetS — Aupes' ops | \ . EXAMINATION CARPENTERS CARPENTERS CappenTERS & feds. No obfestion to’ pes until fata 1?) AND 4g ry \ j mm «you are satisfied. —. coupon BuiLpers BulLDERS ph Ss 2 now—today and get this fine, liclpful new set for Carpenters ‘ ‘ ; ~*~ and Builders. After you ilels a y i 1 barns. er than I antici- | U@ble for the begin- —George H. Wat-]| *‘Save Money” Pp. O. Box 143, pated. 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8 Inventions W antea!? OU can now learn how to train your mind along scientific inventive lines. No longer need you let your mind wander in unprofitable fields. You can learn how to think of worth-while ideas and make your ideas pay you money. The trouble with most people is that they do not know what to do with their ideas. Millions of dollars go to waste because of these un- developed ideas. Now for the first time you can learn to harness your thoughts and make them work for you! One little invention, properly developed, may make you in- dependent for life! °112,600 in Prizes The world wants hundreds of new inven- tions, and will pay big money for them. Even simple inventions—little things like crimped hairpins, the tin bottle-cap, the snap-fastener, the suspenders—have brought fortunes to their inventors. Only recently a. magazine published an article which showed that manufacturers had offered $112,600 in prizes for inventions they want now. You have a glorious opportunity to get one of these prizes—some of them thousands of dollars—if you only learn how to invent. You Can Do It At Home If you have ever had an idea for an inven- tion, or if you would like to become a spare- time or professional inventor, see what this fascinating new course can do for you. Fifteen famous inventors now teach you at home the secrets of invention; show you how to get the information you want, how to perfect your ideas quickly, what to invent, and (just as important) what not to invent. You also learn how to avoid the mistakes which cost many inventors thousands and thousands of dollars. This complete course teaches you everything you want to know—how to get a patent, how to protect your patent rights, how to dispose of your invention to get the greatest possible profits, and hundreds of other facts about invention worth a fortune to you. Write For This FREE Book A wonderful book explaining this fascinating course will be sent to you free. It explains the course in detail, and proves that you can easily train your mind to think inventively so you may become a successful inventor. It shows how this course gives you, in short time, a wealth of in- formation which other in- ventors learned only after years of hard work and bit- ter experience. Get the advice of these fifteen fa- mous inventors. Send for this book today. There is no cost or obligation. This bureau is not con- nected with patent at- torneys or manufacturers. Our only work is to teach you how to develon your ideas so they will bring you big money. BUREAU OF INVENTIVE SCIENCE Dept. 28 Wisner Building, Rochester, N. Y. BUREAU OF INVENTIVE SCIENCE, Dept. 28, Wisner Building, Rochester, N. Y. Please send me without cost or obligation your free book ‘‘The Science of Invention." POPULAR SCIENCE MONTHLY Money Making Opportunities LABORATORY AND CHEMICAL SERVICE EXPERIMENTERS. Complete supplies for the chemical laboratory. Catalogue 5c. 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OF interest to lonely, single folks. City Hall Station, New York EXCHANGE interesting letters with new Dolly Gray Club, Box 186J Denver, Colorado. appreciated. FRIENDSHIP Magazine. Classy Illustrated. 10c. PM. Box 178, New Haven, Conn. LEADING Club, largest, most reliable for lonely people. Established 19 years. Many wealthy members. Quick results. Mrs. Wrubel, Box 26, Oakland, Calif. JOIN Lucky Correspondence Club, results guaranteed. Write Elsa Thorpe, 14 Union Park Ave., Jamaica, N. Y. PLAYS AND ENTERTAINMENTS YOU'LL have lots of fun exchanging cheery letters in my club. Eva Moore, Box 908, Jacksonville, Florida. (Stamp.) want new Box-1167X, (Stamp) Box 846, iriends Stamp CHALK TALKS LAUGH producing program, $1.00. Circulars free. Cartoonist Balda, Oshkos:, Wisconsin. LANGUAGES WORLD-ROMIC System, Masterkey to all languages: Primers, $1.94 each language: Chinese, French, Spanish. Pronunciation-Tables, 30c. Dictionaries, grammars, 4,000 languages. Languages, 8 West 40th, New York. STAMMERING ST-TUT-T-T-TERING and stammering cured at home. Instructive booklet free. Walter ee 59 Poto- mec Bank Building, Washington, D. FOR SALE MISCELLANEOUS ROCKS and minerals for sale—hundreus of varietics— price list free. P. Zodac, 157 Wells St.. Peekskill. N. Y. INFORMATION COMPLETE guaranteed information, eA subject, $1.00. Newspaper, Magazine Clippings, $1.50 ron- berg Clipping Bureau, 3130 Davlin Court, Chicago. COMPLETE, accurate, information on any subject, $1. National Information Bureau, 1429P Milton St., Grand Rapids, Michigan. GUARANTEED information, any subject, confidential, $1.00. Doris Chemical East Cleveland, Box 591, Cleveland, Ohio. LIEEGAL questions answered, guaranteed correct, $1.00. Fdgar Keller, Augusta, Montana. strictly Laboratories, LEARN BY DOING Every phase of all branches ELECTRICITY taught by Actual Practice In America’s foremost and oldest institution for trade training No Books Used Individual Instruction Start Any Day Write for FREE 64-page catalog THE NEW YORK ELECTRICAL SCHOOL 40 West 17th St., New York City Open All Summer Automobile Pattern Drafting By F. X. Morio A concise course of instruction in lay- ing out complete patterns for hoods, cowls, bodies, guards, fenders and other sheet metal parts with chapters on stamping, painting and finishing. In addition there are ten detailed blue prints 15 x 18 inches wide, and also many useful tables. Fully illustrated, $3.00 Automobile Painting By F. N. Vanderwalker In this book the painting of new cars and the repainting of old ones by several different methods are fully covered; tools and materials are described and illustrated and working methods are clearly explained. 200 pp. Illus. Price $1.50 Popular Science Monthly 225 West 39th Street New York City Here’s th ickest way to big pay work. Takes only an hour a dav ag ty time fora pty Ly Robinson jumped from $20 to 00a six months. You, too, can boss Auto Job. I'll show at home. ** Job-W: nd for ig ini aot ay’’ course. Tells about back ree tools offer. Low price Book is eck sunrantee, free A postal will do. Write Now. J. R. BAYSTON, Pres., CHICAGO AUTOMOTIVE INSTITUTE Dept. C-178, 536 South Clark Street, Chicago, Illinois AMERICAN MADE TOYS AND NOVELTIES OPPORTUNITY to start Manufacturing Metal Toys and Novelties. No experience necessary. Enormous demand exceeds supply. We furnish. at cost, casting- forms for production and buy entire output, also place yearly contract orders. Catalog, a Products Co., 1696 Boston Road. New York More Money Making Opportunities on pages 4 to 17 Metal Cast Modern Carpentry FRED. T. HODGSON The most practical and complete work on carpentry. Every detail of the work carefully illustrated. 7 pages. Price $3.00. POPULAR SCIENCE MONTHLY 225 West 39th St. New York City niles ct PRD EAN BOAR met St ae

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N NG of all CITY ictice nost and for trade Used uction lay uge catalog ORK CHOOL York City mer rn 1 in lay- hoods, id other ters on ing. In ed blue ind also Hing new cars y several covered; bed and 10ds_ are |.50 mthly fork City and asy te NOW. yE INSTITUTE cago, Ilinois try yn carpentry. trated. / THLY y York City Money Making Opportunities PHOTOGRAPHY AND SUPPLIES HAVE youa camera? Write for free sample of our big magazine, showing how to make better pictures and earn money. American Photography, 117 Camera House, Boston, 17, Massachusetts. FILMS Developed. Special Trial Offer. Any size Kodak film developed 5c, prints 3c each. Trial 6 x 10 Enlarg t in hand folder 40c. Overnight Service, Roanoke Photo Finishing Co., 212 Bell Ave., Roanoke, Virginia. 8x 10 ENLARGEMENT from your film, colored and framed for 98c, plus 2c for insurance. Cash with order. Send for circular. Alves Photo Service, Braintree, Mass. DEVELOP and print your own films. Complete for- mulas, 60ec (no stamps). Results guaranteed. Studio “L,”’ Owego, N. Y. SPECIAL! Beautiful “Old Masier’’ Enlargement, 8xtO, 11x14 or 14x20, “Sepia or pastel’’ from negative or photo, $1.00 prepaid. Finest equipped plant in Americal Film Artists Productions. Box 417, Los Angeles, Cal. PLAY Safe! If you want every picture perfect send your films to us. Any six exposure film developed 10c; 10 or 12 exposure 15e; vest pocket prints 3c; brownie No. 2 or No. 2A, 4c; larger sizes,5c. 8x10 enlargements 55e. Mailed back same day. Satisfaction guaranteed. Leon Lambert, 670-E South Volutsia, Wichita, Kansas. AUTHORS—MANUSCRIPTS WRITE: for newspapers and magazines. Big pay. Experience unnecessary, details free. Press Reporting Syndicate, 971, St. Louis. WRITERS—Stories, poems, plays, etc., are wanted for publication. Literary Bureau, 117, Hannibal, Missouri. I WANT song poems. Casper Nathan, J-1252 Bryn Mawr, Chicago. BIG money writing photoplays, stories, poems, songs. Send for free copy America’s greatest magazine for writers. Tells you how to write and sell. Writer's Digest, 636 Butler Bidg., Cincinnati, Ohio. $$$ FOR ideas. phen ow plots accepted any form, revised, criticized, copyrighted, marketed. Advice free. Universal Scenario Corporation, 214 Security Bldg., Santa Monica and Western Avenue, Hollywood, California. WRITERS, receive riches and feel the glory of Author- ship through my helpful criticism. Bex 191, Manhattan, Kans‘%s. MUSIC AND SHEET MUSIC POEMS wiunted—SsSell your song verses for cash. Sub- mit MSS. at once or write New Era Music Company, 117, St. Louis, Missouri. WRITE the words for a song. We compose music. Our chief of staff wrote many big song-hits. Submit your song-poem to us at once. New York Melody Corp., 419 J. Romax Building, New York. A 3500 cash prize is offered ior the best second verse to “T'll Be Waiting.”” Those wishing to compete may receive a free copy of this song and rules of contest, by addressing Equitable Music Corporation, 1658 Broadway, N. Y. C. MR. ADVERTISER: Ask to-day for a copy of the “Quick-Action Advertising Rate Folder.” It contains some really important facts which will prove interesting an valuable to you. It also tells ‘‘How You Can Use Popular Science Monthly Profitably.’’ You'd like to know, wouldn't you? Manager, Classified Advertising, Popular Science Monthly, 225 West 39th Street, New York. PHONOGRAPHS, RECORDS, ETC. 50,000 STANDARD 75c, 10-in. Double Phonograph Records, Plays any machine. While they last, 500—15c; 10)—16c. Sample order 25 Records—all different, $1.25. Order today. Andrew Beck, Nashville, Tenn. MOTION PICTURE BUSINESS WRITE photoplays; $50 each. Experience unneccs- siry. Details free to beginners. Producer's League, 312, St. Louis. NOVELTIES ARMADILLO Baskets, Unique novelty; samples par- cel post paid, plain basketg, $2.50; silk trimmed, $3.50 each; satisfaction guaranteed or money back. Address Charles Apelt, Comfort, Texas. CHINESE NOVELTIES ORIENTAL novelties, catalog free, Shanghai Trading, 22 Waverly, San Francisco. OPTICAL GOODS _ ARTIFICIAL eyes, $3. Booklet free. Denver Optic 508 Barclay, Denver, Colorado. DOGS _ BEAUTIFUL registered bull pups cheap; Bulldogs, 201 Rockwood, Dallas, Texas. LETTER SPECIALISTS YORTON writes Forceful, Hard-Hitting, S:les-Pro- ducing —? $3. Send cash with data, B-373-P-S, Syrieuse, N. . MAIL ORDER BUSINESS $50 a week, evenings. I madeit. Mail order business booklet for stamp tells how. Sample and plan 25c. Free, 12 articles worth $3. Alps Scott, Cohoes, New York. ADVERTISE by mail and keep business growing. Let me tell you more. H.J. Keeney, Room 17, Columbia Blig., Paducah, Ky. * MR. ADVERTISER: Ask to-day for a copy of the Quick-Action Advertising Rate Folder.’ It contains some really important facts which will prove interesting and valuable to you. It also tells ‘How You Can Use Popular Science Monthly Profitably.”” You'd like to know, wouldn’t you? Manager, Classified Advertising, Popular Science Monthly, 225 West 39th Street, New York. INCORPORATIONS DELAWARE Incorporator. Charters; Fees Small; jorms. Chas. G. G ¢ Ss 7ilming ‘til Guyer, 901 Orange St., Wilmington, DISTRICT MANAGERS WANTED WORLD'S fastest selling auto accessory! County distributors wanted; write to day. G. L. W., Spring Jiler Co., San Diego, California. WANTED—Representatives in every factory in the United States. Popular § 225 W 39th Street, New York. ee nee a More Money Making Opportunities on pages 4 to 17 POPULAR SCIENCE MONTHLY Want aride toBigPay? a@eiteron | >, Get into the UTOMOTIVE GAME/ Earn $75 to $200 a Week That’s the money for you! And you can have it! Why not? The jobs are open—they’re calling for trained men to fill them—all you need to walk off with a $75 to $200 a week job is training. Get it! Here’s how:—Give us an hour a day, spare time, and we'll quickly put you across to big success in the Automotive Game. We’ve done it for hundreds of fellows just like you—men with perhaps less education, brains and ability. These fellows are holding down big money jobs—run- ning their own business—making something out of themselves—YOU can do it too! For the sake of your dollars and cents future, send the coupon today, and find out just what we can do for you. Learn at Home From 20 Master Experts Here’s a course written not by one man, with the narrow, one-man viewpoint, but by 200f thecountry’s brainiest, most successful Automotive Experts. Fits you for a dozen big pay jobs. Shows how to start and build a successful busi- ness of yourown. Learn it allat home, in spare time, under a money back guarantee of results and satifaction. WRITEY Get Our FREE Auto Book the success of others. Learn how you too can easily earn’'$3500 to $10,000 a year. Seewhy and how this course excels all others. Get our @ special free tuition offer and full informa- tion on EXTRA FEATURES found in no other school or course. Write today for big free book. No obligation whatever. Rush the coupon or a postal today. AC75 Automotive Division Drexel Ave. and 58th St. 7% American School ” Garage Owner ——————— i FREE ~Q Auto Book vo American = School SSH" Devt.AC7S Chicago myo Withouta penny's ex- ay? pense or obligation We please send me Free Book 2° and all information on yous Aa Automotive Course. - : « x ‘Tearn atHome toBoss theJob EARN $3500 fo? 10000qa YEAR Kf

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10 Two Years’ Engineering Course me Civil Compact courses of essentials. mechanical urawing; also shop and field work. time and money, but strong in purpose. what is embraced and what is omitted. Mechanical tary school education. Machinery. If interested, be sure to write. E Electrical POPULAR SCIENCE MONTHLY With Diploma Le and Degree Chemical Richer in higher mathematics. higher science and Planned for those short in Courses distinguished alike for Adapted to Engineers with Practical Experience desiring a Degree No Entrance Examination or High School Diploma Required Indispensable preliminary work provided for students with only elemen- Modern shops, Laboratories, Library, Apparatus and xpenses low. For catalog address § 4 TRI-STATE COLLEGE OF ENGINEERING, Box P-8, Angola, Ind. MEN WANTED! CosnanteeD UARANTEED Earn Up to $250 per Month, Expenses Paid Big demand for trained men in this fas- cinating, new profession. Many splen- did opportunities thru contact with railway officials. Travel or remain near home. Pleasant, healthful outdoor work. Start at $110 per Month with expenses paid. Prepare in three months’ spare-time study at home. Any average man can easily qualify. POSITION GUARANTEED If, after completing pre paration, we do not se- cure for you a position paying at least $110 a month and expenses, we refund Ang enrollment fee in full. YOU TAKE NO RIS Investigate No sau wuwweeneeuucs Send coupon for Standard Business Training ok arranges No. Bt scmgeammee Buffalo, N. Y. , bg Fem hol Booklet Lee 94 coo fF gine” Traffic Inspection. — TRAINING INSTITUTE 8 e Street Buffalo, N.Y. 5 City. Why Good Dancers Are Popular _ rah EY ERYONE admires and wants - to dance with the person — Eo, the latest steps. There is no need of being a wallflower! By my remarkable new easy method any- ome can learn the newest dances at home in a few hours. Much less expensive than from a_ personal teacher. No music or — _ So me Yo en a chi dg have Sy mail. Your own success cs quer. anteed. To prove I can quickly and easily make you an accomplish will send ou FREE in plain cover, a lesson in Fox ot, Secret of Leading. How to follow successfully. The Correct ee A Position and How to Gain confidence op cost of mailing, handling, etc., send 25c. —— a private—surprise your friends. Act Pe @ good dance ARTHUR MURRAY, ‘Studio 239, 290 Broadway, New York —The Book that is Show- ing Thousands the Way to Big Money in ELECTRICITY Establish yourself as an Electrical Expert. Find out how the New Shop Type training fits you at home in a few weeks. Thousands are taking this short cut to bigger positions. Re- markable method guaranteed by famous Lincoln Institute of Technology. Learn all branches without previous experience. Free Employment—unlimited advice—legal binding guarantee of satisfaction or money back. Write at once for information about complete Electrical apparatus and instrun::nts given. Also big new book. No obligation. S. & H. ENGINEERING COMPANY Affiliated with the Lincoln Institute of Technology 1422 W. Monroe St. Dept. H-16 Chicago, Il. Learn Cartooning § At Home—in Your Spare Time from the school that has trained so many successful cartoonists of today earning from $50 to $200 and more a week. The Landon Picture Chart Method of teaching makes — drawing easy to learn. Send 6c stamps for fullinformation and hart to test your ability. Alsostate age. THE LANDON SCHOOL Attend a School Operated by Build- ing Contractors. Three Months Day Course $75.00. 1451 National Bidg., Cleveland, O. ASSOCIATED BUILDING EMPLOYERS 1280 A. B. E. Building, Grand Rapids, Mich. Bricklayer! CONCRETE ON THE FARM AND IN THE SHOP This new book illustrates and describes in plain simple language many of the numerous appliances of concrete within the range of the home worker. Price, postpaid, $1.00 Book Department, POPULAR SCIENCE MONTHLY 225 West 39th Street, New York Money Making Opportunities FOR INVENLOKS INVENTORS’ Educator: 900 Mechanical Move- ments. 50 Perpetual Motions. How to procure and sell patents. Mechanical Movements greatly assist In- ventors, suggest new ideas. Explains how to select an attorney and avoid Patent Sharks. Price $1.50. Postage Acai 5 a E. Dieterich, 681 Ouray Building, Washing- on, D. C. PATENTS—Write for Guide Books and ‘Record of Invention Blank.’’ Send model or sketch of your inven- tion for our free Examination and Instructions. See advertisement on page 105. Victor J. Evans & Co.,, 156 Ninth, Washington, D. C. CASHING in.—If you have a practical, useful inven- tion to sell, write us promptly, stating whether patented. American Patents Corporation, Barrister Building, Washington, D. C. PATENT applic: ations filed with drawing $20; deferred $15; strongest cl.ims; priority rights guarded. Inventors’ Service, 11 Broadwoy, N. Y. TO SELL your patent. write me; experienced handling, immediate action. Address Arthur S. Billings, Suite 401, Dekum Bldg., Portland, Ore. ISELL patents. Established in 1900. Charles A. Scott, 773PS, Garson Avenue, Rochester, New York. GET Your Own Patents. Instructions $1, Cutting, Campbell, Calif. UNPATENTED Ideas Can be Sold. I tell you how and help you make the sale. Free particulars (Copy- righted 1923). be e W. T. Greene, 805 Jenifer Building, Washington, D. PATENT ATTORNEYS PATENTS—Betore disclosing an invention the in- ventor should write for our blank form ‘‘Record of Inven- tion.”” This should be signed, witnessed and returned to us together with model or sketch and description of the Invention for Free Examination and Instructions. Our Three Books mailed free to inventors. Our illustrated Guide Book, “How to Obtain a Patent, contains full instructions regarding patents. Copies of unsolicited letters trom manufacturers and others who are constantly writing us regarding the purchase or leasing of merito- rious patents sent upon request. See advertisement on pare t0s Victor J. Evans & Co., 937 Ninth, Washing- ron UNPATENTED Ideas Can Be Sold. and help you make the sale. Free particulars (Copy- righted 1923). Write W. T. Greene, 811 Jenifer Building, Washington, D. C. “INVENTOR’S ADVISER” the valuable Patent book with 139 mechanical movements and illustrations, sent free upon request.—M. S. Labiner, Patent Attorney, 3 Park Row, New York. PATENTS, trade marks, copyrights. sonal reliable service. Over 30 years’ active practice. Write for terms. Book free. Address E. G. Siggers, Box 1, N. U. Building, Washington, D. C. CANADIAN and Foreign Patents secured. Fine references, reasonable Aigo prompt personal service. The Ramsey Co., 273 A, Bank St., Ottawa, Canada. PATENTS—My foes in inst: aliments. Advice book ‘rank Fuller, Washington, i. PAT ENTS Procured. Send "aa h or model today for examination, prompt report and advice. No charge for preliminary advice. Write for free Booklets ‘‘How to Obtain a Patent’’ and “Invention and Industry’’ and blank form on which to disclose your idea. Highest references. Promptness assured. Clarence A. O'Brien, Registered Patent Lawyer, 1843 Security Bank Building. Directly across the street from Patent Office, Washington, >. See page 103 THE Patentome. Impartial advice to Inventois :nd Manufacturers. Mailed on request. Anderson & Son, Patent & Trade Mark Lawyers, Established 1865, 636 F St., Washington, D. C. INVENTORS: Send sketch or model for free opinion concerning patentable nature and exact cost of patent. Book, “How to Obtain a Patent.” sent free. Tells what every inventor should know. Established twenty-eight years. Highest references. Prompt service. Re:sonable charges. Chandlee & Chandlee, 462 Seventh, Wushing- ton, D. C. H. F. LOWENSTEIN, Registered Patent Attorney Ne ae expert. 817 McLachlen Building, Washington, Cooper I tell you how Prompt, per- MILLIONS, spent annually for ideas! Hundreds now wanted! Patent yours and profit! Write today for free books—tell how to protect yourself, how to invent, ideas wanted, how we help you sell, etc. American Industries, Inc., 501 Kresge Bldg., Washington, D. C LACEY Patent-Sense. ‘‘The Book the inventor keeps.” Free. See page 106. PATENTS—Send for booklet. Contains valuable in- formation for inventors. Our charge for search of Patent Office records $5.00. Prompt service. twenty years’ ex- perience. Talbert & Talbert, 506 McGill Building, Washington, D. C. BUILDING AND FLYING AN AEROPLANE By Charles B. Hayward. A practical handbook covering the design, construction and operation of aeroplanes and gliders. 150 pages. price $1.00. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York WANTE RAILWAY MAIL CLERKS $1600 to $2300 Year MEN—BOYS, 18 OR OVER SHOULD MAIL COUPON IMMEDIATELY Steady work. No layoffs. Paid vacations Travel—see your Country ’ Common education sufficient. 7 Mail coupon today—SURE , @ FRANKLIN INSTITUTE, Dept. L-277, Rochester, N. Y. 4 Sirs: Send me without charge, (1) Specimen = et A Mail Clerk Examination questions; (2) (e) List of U.S. government jobs now open to men, 18 up (3) Send Tice of examination places; (4) S illustrated book, tions.* nd ro “*“How to Get Government Posi- Oe ee ere Ter PATENTS. trate st Highest references. Best results. dbaremeage «yagi Watson E. Colem:n, Patent Lawyer, 644 G + Street, w ashington, D. C. PATENTS PROCURED; trade marks registered—A comprehensive, experienced prompt service for the protec- tion and development of your ideas. Preliminary advice gladly furnished without charge. Booklet of information and form for disclosing idea free on request. Richard B Owen, 44 Owen Bidg., Was — D. C., or Rooms 809-810 41 Park Row, New Yor INVENTORS’ Guide free on request; gives viluuble information and advice for all who have original ideas or improvements. Frank Lederman, Registered Attorney and Engineer, 15-S Park Row, New York. ESTABLISHED 1864. Milo B. Stevens & Company. Registered Attorneys (No. 830). Patents, Trade-Mzrks, Copyrights. Full information upon request. Mocierate fees. Offices: Barrister Building, Washington: Leader Building, Cleveland; Monadnock Block, Chicago. MONROE MILLER, Ouray Blidg., Washington, D.C. Patent Attorney; Mechanical, Electrical E xpert. Free Blue Book gives candid advice. HERBERT JENNER, patent attorney and mechanical expert, 606 F Street, Washington, D.C. I report if patent obtainable and exact cost. Send for circular. INVENTORS—Send for form ‘‘Evidence of Concep- tion” to be signed and witnessed. Form, fee schedule, information free. Lancaster and Allwine, 232 Ouray Bldg.. Washington. D C. More Money Making Opportunities on pages 4 to 17 Sn AAR Ne PRY 2 htyeahees TRUSS Ua alan Reese

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per how opy- ling, antly rito- it on hing- how ‘opy- ding, book sent ey, 3 per- ctice. Beers, Fine rvice. ilding. ngton, iS und &« Son, 5, 636 »pinion uilding, . Best olem::, sred—A : protec- y advice rmation B valuable ideas or \ttorney ym pany. -Murks, focierate Leader >. Bn, D.C., t. Free chanical if patent —— Concep- schedule, 2 Ouray —— ities —, Ke re ° xs rd j (oan FEM a Ww WZ » as Get Behind a Hohner for Happiness! There’s nothing like good music for happiness; and there’s nothing like a Hohner for good music. Any boy or girl can learn to play real music quickly with the aid of the Free Hohner Instruc- tion Book, procurable at all good dealers. And all good dealers sell Hohner’s Harmonicas— The World's Best “That Musical Pal of Mine” is a favorite expression among Hohner en- thusiasts everywhere. Hohner enthusi- asm is sweeping the country. Why don’t you get in line for popularity and enjoyment? Go to your dealer today, get a Hohner Harmonica—50¢ up—and ask for the Free Instruction Book. If your dealer is out of copies, write M. Hohner, Inc., Dept.182, New York City. OHNER ARMONICAS 7 I Teach By Mail I can make a good penman of you at your home during spare timc, no matter where you live or how poorly you now write. My simplified system has shown thousands the way to good penmanship during the past twenty-five ycars—it CAN and WILL - the same for YOU— ““My beautifully | fllustrated 32- -page Book “Hew to Become a Geed Penman’”’ FREE!! It contains many beautiful specimens of penmanship showing what others have accomplished by the Tam- blyn System, with testimonials and general information about our course—( Your name elegantly written on a card if you enclose stamp Jor postage). eS 's taught as successfully as men. WR TODAY, address « W. TAMBLYN Kansas City, Mo., 437 Ridge Bide.” U.S.A. SSESe - I > “of BGGort Uae ed 7 TIRES WITH 500 NAIL HOLES LEAK NO AIR A new puncture-proof inner tube has been invented by a Mr. M. E. Milburn of Chicago. In actual test it was punctured 500 times without the loss of air. This wonderful new tube increases mileage from 10,000 to 12,000 miles and eliminates changing tires. It costs no more than the ordinary tube. Mr. Mil- burn wants them introduced everywhere and is mak- ing 2 special offer to agents. Write Sales Manager. G. U. Hansen, 336 West 47th St., Chicago. Money Making Opportunities POPULAR SCIENCE MONTHLY AGENTS AND SALESMEN WANTED ONLY one sale a day means $200 per month! sales $1,000 per month. i new adding machine. Retails $15.00. Work uals $350 machine. Adds, subtracts, multiplies, divides automatically. Speedy accurate, - durable, ndsome. Five year guarantee. Offices, ‘stores, factories, corneas a one A fortune for live agents. uick for protected territory and free trial offer. Myr Calculator Co., Dept. P, Grand Rapids, Michigan. AGENTS, both sexes, we manufacture and control new household article. Fast seller. Big profits. Exclusive ter- ritery. Write now. Connolly, 123 Liberty St., New York. SALESMEN, can make $5.00 a day selling our calen- to dozen. dars, pencils, signs, advertising novelties, yardsticks, whistles, etc. Liberal terms. Sells entire year. Fine sideline. Local and traveling agencies. Model Calendar Co., Dept. 309, South Bend, Indiana. EASY, pleasant work for mechanics, shop men, clerks, during spare hours, will add many dollars to their sa’aries. Also want cae omg who can give full time. Big wages assured. velty Cutlery Company, 27 Bar Street, Canton, Ohio. $60-$200 A WEEK. Genuine Gold Letters for store = Easily applied: Free samples. Liberal offer general agents. Metallic Letter Co., 434A North Gat Chicago. INSTANT Weld—Repairs largest punctures without cement or heat. Lenn’s profit one day $56. Write quick. Free sample. Territory going fast. Tourist’s Pride Mfg. Co., Desk R, Minneapolis, Minnesota. FREE Sample “Rain Shield Wiper.” Retails $1.00— Costs (25c). Sold Clear and Rainy Days. No Cloth— No Paste—No Attachment. (1) Rub keeps Windshield Clear (48) Hours. Experience Unnecessary. Nulife Corporation, Hartford, Conn. MAKE money silvering mirrors, oll kinds plating, knives, spoons, auto headlights. Outfitsfurnished. Free Booklet. International Laboratories, Dept. 27, 311 Fifth Avenue, New York. AGENTS—100% profits. Fast-selling novelty for one ge gga Emblematic Belt Co., Dept. D., Ash- an 0. BIG money and fast sales. Every owner buys gol initials for his auto. You charge $1.50, make $1.44. 10 orders daily easy. Information and samples free. World Monogram Co., Dept. 25, Newark, N. J. EVERYBODY uses extracts. Sell Duo Double strength Extracts. Complete line household necessities. Big repeaters. Write today. Duo Co., Dept. E66, Attica, N. Y. STAMPING names on emblem key checks. 20c. Key check outfits, steel dies, key cases, etc. Sales Corporation, Shelby, Ohio. AGENTS—Clever Invention! pen a fountain pen. Sample Service Inkspoon makes every Fast office seller, big profit, demand increasing ware. Exclusive territory _ offered. Sample free. H. Marui Company, Tribune Building, New York. AGENTS—Best seller; 800 per cent; put it on cold, it vulcanizes itself in two minutes, and is guaranteed to last the life of the tire or tube; sells to every auto owner and accessory dealer. For particulars how to make big money and free sample, ad- dress Amazon Rubber Co., 504 Amazon Building, Phila- delphia, Pennsylvania. AGENTS! At last a perfect Knife Sharpener. A sure seller and a money-maker. Retails $1.00. 100% profit. Guaranteed a lifetime. Write, Conaway & Conaway, Dept (C) Champaign, II. EVERY house a sale; Fast sellers; Particulars. Hel- mers Company, Desk No. 12, Hoboken, J. Jem Rubber Repair for tires 50% PROFIT selling name cards, penknives, sta- tionery, catalog. Wolf Labels, 1309 E. Levick Street, Philadelphia. 31 BILLION, 650 million marks, real German currency ~ only $1.00. ‘Wholesale prices with order only. Atlantic Co., 1209 Beach Ave., Bronx, New York. MAKE $25 to $50 week representing Clows Famous Philadelphia Hosiery, direct from mill—for men, women, children. Every pair guaranteed. Prices that win. Free book “How to Start” tells the story. George Clows Company, Desk 24, Philadelphia, Pennsylvania. $10 to $25 Daily, No Investment. Free outfit. Best values. Largest commissions. World Raincoat Company, 659-8. Morris Park Ave., New York. MAKE $17 Ly oS Finest extracts, —" preparations, ho’ ase free. Write for amazing offer. B-26, Hastings, Nebr. WE start you without a dollar. Soaps, extracts, per- fumes, toilet goods. Experience unnecessary. Carnation Co., Dept. 21, St. Louis. SALESMEN sell sales and order books, auto, reg. rolls and bill ladings. Large demand. Liberal com- mission. Wirth Sales Book Co., Dept. PS, Chicago. MEN and women representatives wanted to take orders for Annie Blzin flavoring extracts in every locality, wholesale and retail; new selling system; free samples to public and other unique pas. Address Annie Blain Co., New Brunswick, N. WONDERFUL discovery. G —— batteries in ten minutes. Gallon free to agents. MRadiolite Co., St. Paul, Minn. FREE Copy—Big Fun Magazine. Representatives wanted. Fin-Ko, 944-P Clark, Toledo, O POLMET—The Wonderful Polishing Cloth tht cleans all metals without liquid, paste or powder. Ap- proved by “‘Good Housekeeping” ud “Modern Priscilla’ —sells fast at 25c. Sample Free. F. C. Gale, 15 Edinboro St., Boston. AGENTS—Household necessity, sells quickly. profits. Square deal. Detroit, Mich. $10.00 DAILY retails 25e. Send 10c for sample. Wilmerding, Penna. ARE you old at forty? 100 of this issue. The Electro Thermal Company, 4036 Main Street, Steubenville, Ohio. EARN $10 daily silvering mirrors, plating and re- finishing metal ware, headlights, chandeliers, bedsteads. Outfits furnished. F. Decie Laboratories, 1133 Broad- way, New York. More Money Making Opportunities on pages 4 to 17 food products, usehold necessities. Credit; sample Perkins Products, Te Premier Mfg. Company, Dept. easily made selling Needle Cases; Mail Order Housc, See our advertisement on pare hive “I’m Going to Make More Money!” “I’m tired working for a small salary. I know I have just as good a head on me as Fred Moore and Bob Roberts, for we used to work side by side. But they’ve gone far ahead of me. “Why? Because they saw the value of special training, and I didn’t. “But I know better now. If the International Correspon- dence Schools can raise the salaries of men like Fred Moore and Bob Roberts, they can raise mine, too! “Tf they have helped others to advance, they can help me. To-day—right now—I’m going to send in this coupon and at least find out what the I. C. S. can do for me.” ~ INTERNATIONAL L CORRESPONDENCE SCHOOLS Box 7602-D, Scranton, Penna. Without cost or obligation on my part, please tell me how I can qualify for the , or in the subject before which I have marked an X: BUSINESS TRAINING COURSES OBusiness Management OJ Salesmanship (Industrial Management L) Advertising (Personnel Organization Better Letters _ () Traffic Management Show Card Lettering () Business Law Stenography and Typing (Banking and Banking Law Business English (J Accountancy (including C.P.A.) LJ Civil Service (Nicholson Cost Accounting Railway Mail Clerk (_] Bookkeeping Common School Subjects () Private Secreta High School Subjects oO French Spanish Llustrating TECHNICAL AND INDUSTRIAL COURSES 1 Electrical Engineering [] Architect [| Electric Lighting r) Architects’ Blue Prints Contractor and Builder Architectural Draftsmap -) Concrete Builder [] Structural Engineer Chemistry (1) Pharmacy Automobile Work [] Airplane Engines [} Agriculture and Poultry (} Mathematics [}Mechanical Engineer | }Mechanical Draftsman [}Machine Shop Practice [}Railroad Positions [)Gas Engine Operating [}Civil Engineer C]Surveying and Mapping Metallurgy O Mining Steam Engineering D) Radio NQIE........--cccsccccccseccccccscecccssccccssscessscnsssscoccscesscesersersceesreeeseee Street 3-6-24 AGEROBB 000. ccccsecccesscccccccoccseseeessccccscccenss sosccscccerscccssessescecess naa Occupation. ..........cccccscsesscscersecceeressertereseceesscsrsenesteessesecsrsneee Persons residing in Canada should send this coupon to the | International Correspondence Schools Canadian, Limited, Montreal, Canada

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There is such an urgent demand for practical, trained Draftsmen that I am making this special offer to deserving, ambitious men. I will: teach you to become a Draftsman and Designer until you are drawing a salary of $250.00 a month. You need not pay me for my personal instruction or for the complete set of instruments. But you must take advantage of this special offer at once. $300 a Month Salary= $450 on the Side At Home That’s the kind of money my drafting stu- dents make. Read what this one says: **As a beginner I am doing fine. Am earning a salary of $300 per month, besides I made over $450 at home the last two months, drawing plans for private parties. The practical drafting training you gave me by mail put me where I am in less than s:x month’s study. Thank you forall your personal interest and help you Draftsman &avemesofsar.”’ (Signed) J. B. Dobe (Name and address upon request) Write and I’ll tell you how I make you a first- class, big-money-earning draftsman ina very few months! I do this by a method no other man_ or ig yo can imitate. give I Guarantee you personaltraining at home by mail un- To train you until | til you are actually you are placed in; placed in a position @ position paying | payingupto$250and up to $250 and| $300 a month. Six $300 a month thousand draftsmen wanted everymonth, This Outfit FREE I give you a whole set of drafting tools the minute you become my student. You get every tool you need. A magnificent set of instruments which will build your success in draftsmanship. on at once for my great book — “Successful Draftsmanship.” Find out about the simply marvelous opportunities ahead now. What reat salaries and possibilities there are! Send the coupon for free book TODAY! POPULAR SCIENCE MONTHLY Money Making Opportunities AGENTS AND SALESMEN WANTED STATE Manager. Envelope Sealer seals 3500 en- velopes hour. Amazing invention! No competition. Retails $5, only. $20,000.00 yearly. RED-E CO., Dept. A. F., 100 Boylston, Boston, Mass. MAKE $100 weekly in spare time. Sell what the public wants—long distance radio receiving sets. Two sales weekly pays $100 profit. No big investment, no canvassing. Sharpe of Colorado made $955 in one month. Representatives wanted at once. This plan is sweeping the country—write today before your county is gone. Ozarka, 803 Washington Blvd.. Chicago. PATENTED Cigar Lighters with Glass Advertising Front. Also Electric Cigar Moisteners. Wonderful Sellers. No Competition. Big Steady Profits. Proof, Cuts, Sales Plan Free. Drake Mfg. Co., Dept. P., Milwaukee, Wis. DUSTLESS Sponge Cloth. New Invention. (1) Rub—Dusts, Cleans and Polishes Automobiles. Furni- ture, Pianos, Retails 50c.—Costs 1l6c. Sample Free. Nulife (H) Sponge, Hartford, Conn. MEN only. Sell new novelty. Sample 25 cents. How- ard Eddy, Meriden, Connecticut. EASY work, big profits seHing automobile spring lubricators. Automatic Spring Oiler Co., Drawer 18, Corona, New York. GET our plan for monogramming automobiles, trucks, hand luggage and all similar articles by transfer method; experience unnecessary; exceptional profits. Motorists’ Accessories Company, Mansfield, Ohio. GET our free sample case toilet articles, perfumes and specialties. Wonderfully profitable. La Derma Co., Dept. F, St. Louis, Missouri. AGENTS: Big profits. Best and cheapest window letters made. Easily applied. Dime brings five samples. Particulars free. Staibrite Company, 1115 Second Avenue, New York. AGENTS—$75.00 Weekly Selling Nustile Guaranteed Hosiery. Your pay daily. You write orders, we deliver and collect. Special monthly bonus. Sample outfit furnished. Nustile Hosiery Mills, Dept. 400, Philadel- phia, Penna. SALESMEN—nsell **Amenz” radioux shirts; guaranteed to wear one year. Very libersl commissions. Get our proposition first. Menzin Shirt Co., 479 East Tremont Ave., New York. BIG money and faust sales. Every owner buys gold initials for his auto. You charge $1.50; make $1.35. Ten orders daily easy. Write for particulars and free samples. American Monogram Co., Dept. 47, East Orange, New Jersey. AGENTS: Bill Omeis, just an ordinary fellow, made over $5000.00 during 1923 selling our $1.50 kitchen specialty. He is now a district manager. We are offer- ing you the same proposition—an opportunity as big as you want to make it. You can do what Omeis did. .Write today, M. H. Tyler Mtg. Co., Dept. P-1. Muncie, Ind. BUILD permanent business. Men’s, Women’s, Chil- dren's guaranteed shoes direct to wearer. A. P. Condon, Sales Manager Allen Shoe Co., 110 Summer, Boston. STOP Right Here. Make real money this summer. Week's salary often made on one sale. Look at our salesmen’s monthly averages—N. Y. man, $600.00; N. Dakota man, $500.00; Ind. man, $750.00, and so on. You call on business men only. Introduce entirely new proposition. No competition. Rich territory open. No collections, No deliveries. You take orders—we do the rest. Write—get complete dope. National Advertising Service, Inc., P. O. Box 74, LaGrange, Ind. BEST proposition in the Specialty field. Perry Lykoil Paintings. Photo Medallions, and Novelties have no equal. Every interview means a sale. 600% profit. Write for details. Perry Photo Novelty Corporation, Sect. PS7, 360 Bowery, New York. TAILORING agents—50 good men wanted, who can “arn $50 weekly and up. Our line contains 220 big value all wool fabrics to retail at $25 to $47.50 for suits and overcoats. Your profit $5 to $9.50 in advance. Big 6 x 9 swatch outfit free. Ref. req. R. B. Ferrin, Megr., P. O. Box 1097, Chicago. BIG Money and Fast Sales—Everybouy— Il: verywhere, Everyday finds hundreds of uses for Dern I:-Z Univers::! Fabric Cement—Good exclusive territory still open. Darn E-Z Laboratories, Dayton, Ohio, Dept. P. M. EARN $40 to 345 extra every week taking orders for our high-class tailoring—made-to-measure suits from $14.95 to $39.50 Your own clothes at low wholesale prices. No experience necessary. Write for our Big Free Sample Outfit. _Progress Tailoring Company, Dept. H-417, Chicago, Illinois. OVER 250% Profit: Salesmen—Crew Munagers— Agents: Large profits, easy sales, satisfied customers are prime factors in selling. Midwest Household Necessities embrace these factors. Particulars free. Midwest Drug Co., 190 East Naghten St., Columbus, Ohio. RUM MAGE Sales make $50.00 daily. Offer wonderful velues. We start you. ‘‘Wholesale Distributors,’’ Dept. 34 609 Division Street, Chicago. SELL Pearl Necklaces. 500% profit. Everybouy wants one. Easy to sell. Write for rock-bottom prices. Star Import Company, 63 Second Avenue, New York. RETIRE in five years, selling our Super 1-2-3 Bull Gum Machine Deals. Six balls for three cents. 100% rofit. Cuts furnished. Purity Gum Co., 273-20th St., Milwaukee, Wis. A BUSINESS Of Your Own. Make Sparkling Glass Name and Number Plates, Medallions, Checkerboards, Signs. Big illustrated Book Free. E. Palmer, 513 Wooster, O. Free Course Offer Coupon CHIEF DRAFTSMAN DOBE 1951 Lawrence Ave., Div. C-136 Chicago Without any obligation to me please mail your book, ‘‘Successful Draftsmanship’’ and full par- ticulars of your liberal ‘*Personal Instruction’’ of- fer to a few students. It is understood I am obli- gated in no way whatever. Name. Sane Address INSTANT Weld—Repuirs largest punctures without cement or heat. Lefin’s profit one day $56. Write quick. Free sample. Territory going fast. Tourist's Pride Mfg. Co.. Desk R, Minne polis, Minnesota. SELL the livest quickest selling specialties ever known. Famous “Hahway”’ self-lighting pocket cigar lighters and gas lighters. Low prices. Easily demon- strated. Sell to dealers. Employ sub agents. Exclusive territory. Make over 100% profit. S. Bernhardt, 148 Chambers Street, New York. $5 TO $15 daily, easy—introducing New Style Guar- anteed Hosiery—must wear or replaced free—no capital or experience required—Just show samples—write orders. We deliver and collect—Your pay daily in ad- vance. Elegant outfit furnished. All colors—grades— incluling silks. Macochee Textile Company, Room 1528, Cincinnati, Ohio. More Money Making Opportunities on pages 4 to 17 Elements of Industrial Chemistry By Allen Rogers General Processes; Water, Its Uses and Purification; Fuels; Sulphuric Acid; Nitric Acid; Elements and Inorganic Compounds; Ceramic Materials and Products; Pigments; Fertilizers; [llumi- nating Gas; Coal Tar and Its Distilla- tion Products; the Petroleum Industry; the Destructive Distillation of Wood; Oils, Fats and Waxes; Lubricating Oils; Soap, Soap Powder and Glycerine; Essential Oils; Resins, Oleo-Resins, Gum- Resins and Gums; Varnish; Sugar, Starch, Glucose, Destrin and Gluten; Textiles; Dyestuffs and Their Applica- tions; the Paper Industry; Explosives; Leather. 500 pp. Illus., Price $3.00, postpaid. The Vest Pocket Bookkeeper A simple and concise method of practical bookkeeping, with short cuts in figures and complete instructions for the correct keeping of books of accounts. A working model adapted to the novice and business man is included. 160 pp. Price $1.00, postpaid. The Vest Pocket Lawyer A complete law course—clearly ana- lyzed in understandable English. It is a daily guide—a manual of reference for the business man—the law student— the justice of the peace—the notary public—the farmer—the clergyman— the merchant—the banker—the doctor. 360 pp. Price $1.50, postpaid. The Real Estate Educator A most comprehensive yet concise arrangement of useful facts about buy- ing, selling, leasing and sub-letting of Real Estate, contracting, for erection or repairs, mortgaging, transferring, in- suring, etc. 256 pp. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York, N. Y. Price $2.00, postpaid. eT. eee GRRE LOSES Sy IG ay Gat Pa Hagerty mir

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ses id; nic and mi- lla- ry; od ; ils; ine; um- gar, cen; ica- ves; aid. cuts s for unts. ovice paid. at ana- It is ‘rence eat— otary lan— octor. tpaid. te oncise t buy- ing of tion or g, in- st paid. THLY s, N. Ye ¢ é § : Sir one Lodge se ee Games discov will not become generally known pee post AA has sufficient wisdom to handle the power that it will loosen. But scientists have already tapped this source of power! Not yet harne: perhaps but yet plain enough that ANY AVERAGE PERSON can toa large ex- tent demonstrate it in daily life. With the use of this ENERGY you can ac- complish anything humanly possible. This FACT has been proven the actual experience of thousands of people during the last twelve months in whose hands we freely placed this amazing discovery. You not only “get the idea” but it applies itself to your affairs within a few days. NOTHING IMPOSSIBLE Literally thousands of people changed their lives almost overnight by this revelation. With this secret Col. Adams of Salt Lake City made over $4.000 in a few days. Unless this power will immediately and prac- tically WORK for you, unless you can demon- strate it as clearly as a child demonstrates elec- tricity by turning on the electric light. IT IS WORTH NOTHING TO YOU. For all men are not equal. Doubt, fear, suspicion, distrust, irresolution are chains that make slaves of meny. SEND NO MONEY—JUST THE COUPON Use the coupon below and mail at once. When the Complete Course reaches you sim- ly pay the postman only $2.85; 10,000 others fo. paid up to $25.00 for these same wonder- ful instructions. Put the simple principles to work immediately, and if, after five days, you decide that the remarkable course is as valuable to you as to others, keep the complete instruc- tions for regular use. If not fully satisfied, simply return the Course and we will refund your money’ at once. CARNAGEY INSTITUTE, 601 Hayes Bldg., Kansas City, Mo. Send me the Complete Instructions, ‘‘Mak- ing Men Think Your Way.” I will pay the post- man $2.85 on arrival and promise to try the Course five days. 0 DD) 2d 22 eer AO TO on mC OTIC (If you expect to be out when postman calls, send money order or check with this coupon.) BIG JOBS! $150 to $400 per month for = — > ne epee electrical fields. Youcanquali- fy after eight weeks in the Yous MeSweeny Schools—-where you learn by working with real tools onreal jobs instead of studying \# from books. Special tuition offer, RB. R. fare paid, 8 weeks board free. Get catalog. McSWEENY Operating Rahe Auto School at Cincinnati & Cleveland Auto School 9th & Walnut, Cincinnati, 0. 1815 E. 24th, Cleveland, 0. Dept. 266 Drat an Expert in In Spare Time at Home Master Drafting and a big job will be waiting for you. ‘ot enough really able men are available to fill the high salaried positions offered by railroads, manu- facturers, architects, contractors, electrical works, etc. Chicago Tech. will train you by mail—make you an expert—through practical instruction by experienced men. Moderate fees. Easy terms. F R E Find out before you enroll or pay a E posay — ey a =e oo ‘ollow Drafting. ther schools as Trial Lesson fee and enrollment at once. Chicago Tech. sends the free lesson first. Write today. Chicago Technical College, 831 Chicago Tech. Bldg., Chicago POPULAR SCIENCE MONTHLY Money Making Opportunities f AGENTS AND SALESMEN WANTED MORE Dollars for You. Wonderful side line or ior your whole time. Wherever you go, you can make splendid profits selling the marvelous Security Check Protecting Fountain Pen. Writes and positively pro- tects checks quickly and easily. Even without this check protecting feature, it would be a fast seller, because it wii so smoothly, the ink flowing easily and evenly and it is so durably made. But when added to these merits, you can so quickly demonstrate its check protect- ing feature, the sale is clinched right then and there even though the prospect may using some other make of pe. He will surely discard it in favor of the Security. he Security makes friends for you. Every business man is a potential and logical prospect and every pen sold will help to sell others for you and thus rapidly increase your income. The amount you can make will depend strictly on how many demonstrations you can make. . .00 yearly and up is being made easily by Security salesmen. A five-year written guarantee with each pen. Fully pro- tected by basic patents. Write for our interesting propo- sition today. Security. Pen Corporation, Dept. G-8, 910 W. Jackson Bivd., Chicago. WOMEN—Henmstitching-picoting attachment, fits any machine for home use. .50 sent collect. Agents vases. National Sales Co., 12th floor, 6 N. Mich., cago. AGENTS, Salesmen—Sell New Thermostatic Auto- matic Carburetor Control Attachment for Fords. Big Profits, full or part time. Burns 95% air. Doubles Mileage. Attached in 2 minutes. No drilling. Does automatically exactly what Ford Manual says do by hand. Cadillac now using thermostatic Carburetor Control under Blancke License. Write today. A. C. Blancke & Co., Dept. 111-A, 602 Lake St., Chicago. SALESMEN—Saleswomen: Our “Better Plan” assures you: permanent business—substantial profits— automatic repeats and’ success, positively. We make one line only—highest quality toilet preparations that sell and re-sell all year round on their genuine superior merit. Affinity Company, 27 South Division Avenue, Grand Rapids, Michigan. HIGH-GRADE men wanted as distributors for nation- ally-advertised article. Not a temporary job but the opportunity to establish an ever-expanding business with generous and steady profits. Write giving details of your past business experience. go considered = eae of receipt. CFSCO, 16 N. 10th St., Richmond, nd, SALESMEN: Earn $50.00 weekly selling custom- made shirts at ready-made shirt prices. 125 latest pat- terns; prices $2.95 up. Shirts individually cut. Uncon- ditional guarantee. Jacobs’ Custom Bilt Shirt Company, 538 Broadway, New York. DO you want to go into business for yourself at our risk? For particulars write Ray Neckwear Co., 523 Ikast 47th, Chicago. Dept. P. SUCCEED with your products—}ormulas, Processes, Trade-Secrets. Different, dependable, profit- able. Catalog free. C. Thaxly Co., Wash., D. C. GET my money getters and great repeaters. Carry with other goods. A. B. Reid, 94 Mosser, Akron, O. SALESMEN wanted to sell our line of labels us side line. Commission. Patrick Label Co., 49F South Ave., Rochester, N. Y. MARVELOUS Radio Gas Lighter sclis instantly; retails 25c. Costs $10.00 gross—$26 profit. Send $1.00 for sample dozen with self-selling plane. L. Masterlite Co., 110 East 23rd, New York. WE Start You in Business—No Capital Required. Monogramming Automobiles, Luggage, Windows, Wag- ons. Six Initials Bring $1.50—Costs You Only 6¢. Transferred as Easy as Applying Stamps on Envelopes. No License. No Experience. “Samples Free.”” NuLife (H) Monogram Works, Hartford, Conn. SELL union label all-wool made-to-measure suits direct to wearer for $24.50. Scott System, Wholesale Tailors, 99 Bedford Street, Boston, Mass. $10 TO $50 a day Cleaning Carpets, Rugs, Clothes. Get in Business; do it now. on’t pass this up; this is your opportunity. We will send Cleaner and direct you for $1.00. Agents wanted. A. D. Cleaners, 1403 llth Ave., Oakland, Calif. AGENTS—$15 a day easy. Best-selling specialty on market. Full particulars tree on request. Address The Horsey-Bassett Co., Dept. PS-8, Crisfleld, Maryland. MAN Wanted by largest concern of its kind. Part or full time. Experience unnecessary. Our men getting up to $200.00 weekly. Lowest prices. Red Seal Coal Com- pany, 385 Coal Exchange Building, Chicago. AGENTS: Our a all-wool tailor made suits—o’coats at $31.50 are $20 cheaper than store prices. Fall line greatest ever. Easy to sell, we train you. Comm. in advance. Write for great new sales plan, J. B. Simpson, Dept. 922, 843 Adams, Chicago. STEADY repeat business assured agents selling to women and homes. Complete line. Toilet and House- hold preparations. Colonial Chemical Co., 631 Penn Ave., Dept. H., Pittsburgh, Pa. SELL Radio Crystal Receiving Sets. Guaranteed sample and working outfit to agents ($1.00) prepaid. Southern Co., Box 217-P, Washington, D. C. BIG Profits—Rubber Specialties. Fifty fest sellers. Everybody needs and buys. Fifty dollars weekly easily made. B.G. Rubber Co., Dept. 612, Pittsburgh, Pa. AGENTS: Three neckties boxed singly for $1.00— Retail $2.00. Cash with order. Maxwell, 401 Searle Bldg., Rochester, N. Y. TAILORING Salesmen: tailors on earth own Oldest established wholesale pay Largest Commission and give Liberal Bonus taking orders for union made $45.00 all wool suits at $31.50. Big outfit and advertising furnished free. Exclusive territory. Experience unnecessary. Wilson Tailoring Co., 936 W. Jackson, Chicago. BIG Profits with Exclusive Territory—$50 to $100 weekly easy. More has often been made in one day’s work. A hot or cold running water bath equipment for any home at only $7.50. No plumbing or water works required. Investigate. Send no money. Write today, Sanitary Supply Co., 722 Allen Building, Toledo, Ohio. EVERY Ford owner in the world wants this! The Hamer Visible Vaporizer guarantees increased mileage (3 to 8 miles per gallon), more power (40% and better), quicker pickup, no carbon, smooth running motor, less heat, longer life, more driving comfort. Sells $4.50; your commission, $3. Exclusive territory. Details and proofs. Visible Vaporizer, Dept. 17, Chamberlain, 8. D. More Money Making Opportunities He Climbed @ee from $60 a month to $10,000 a year Ten thousand a year! That is what a North Carolina man is averaging — even in dull years—as partner in an independent firm of Certified Public Accountants. Yet six years ago, when he started the study of Higher Accountancy under the LaSalle Problem Method, he was earning only $60 a month, was married and had also a little daughter to provide for. Lots of men would have thought they were hopelessly up against it. But this man was made of different stuff—there was nothing of the quitter about 47/ He ac- cepted LaSalle’s offer of easy terms, and started to study Higher Accountancy at home in his spare time. Today, he has the great satisfaction of knowing that he has made good. He is able to live the way he wants to live—to give his family the com- forts and luxuries he has always longed to provide forthem. He has proved his right and title to success. His Chance Is Yours The experience of this man (name fur- nished on request) is not an isolated exam- ple. Hundreds of men have won rapid advancement thru LaSalle Higher Account- ancy training. They got their start by sign- ing just such a little coupon as appears directly below this text. Mark that coupon, sign and mail it today— and get the facts. We will promptly send you com- plete information regarding the opportunities for men trained in Higher Accountancy, also a copy of that inspiring book, ‘“Ten Years’ Promotion in One.” “Get this book,” said a prominent Chicago executive, *teven if you have to pay five dollars for it.” We will send it free. Remember, the cost of LaSalle training is small and can_be covered in easy monthly pay- ments, if you so desire. The decision that you make this moment is zmzportant. Mail the coupon now, - —— —= = JNQUIRY COUPON = ——=— LaSalle Extension University The Largest Business Training Institution in the Wor. Dept.883-HR_ Chicago, Ill. Please send me your book, “Accountancy, the Profes- sion That Pays,” and full information regarding the course and service. Also a copy of your book, “Ten Years’ Promotion in One,” all without obligation to me. es O Higher Accountancy > Training for position as Comptroller, Auditor, Certi fied Public Accountant, Cost Accountant, etc. Other LaSalle Training Courses ee LaSalle is the largest business training institution in the world. It offers training for every important business necd. If more interested in any of these courses, check here: OBusiness Management OModern Salesmanship OTraffic Management ORailway Station Management OLaw— Degree of LL.B. OCommercial Law OiIndustrial Management Efficiency O Modern Business Corre- spondence and Practice OBanking and Finance O Modern Foremanship and Production Methods OPersonnel and Employ- ment Management DExpert Bookkeeping OBusiness English OCommercial Spanish OEffective Speaking Oc. P. A. Coaching Pieactt Pasitiete) oe ee on pages 4 to 17 Pn I ants

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14 POPULAR SCIENCE MONTHLY E & arti Just Out 13th Edition A NEW AND GREATER Electricity "Ss. an Entirely Rewritten, Rearranged and Illustrated = ° 9, Greatly Enlarged; 1238 Pages, 4143 Illustrations. America’s Grea A Practical Book for Everybody agen Home Study Somene ol ry in id Wem | | tt, bal E : E CT RICIT Y LOPEDIA erence and . ey” guide. Don't Miss it The Auto Think of it! Ten Owner wil! days’ training free! Here’s the know how to chance to prove to yourself that . Electricity is the big pay field diagnose for you—that our course is the St d ‘ ; bi ae troubles and Passa arg ne pers ee wney tod lent it wind Sta t f ' ¢ she Sen an Gaye ae t Sch as a | dl § know when decide. Our training fits you for | ne 4 repairs a dozen big-pay jobs, or your own Cc ) ¥ N E —————— are done business. Get the facts! right. You can’t risk or lose a penny, The Student So write quick for i\ywaes Earn $200to | ) fundamental f IN: W. a PSP SIGE 2 STS ch a UN Reta ea cab AESOP DAT 9 ‘ieee

American inciples, the $800 | month! key to a successful in SYS School Dept. E. C. 75 = rite New Enlarged Course Chicago Quick +. e Y k 0} thing f. door-bells to ere hi ©A. S. 1924 Hou rovk on ruhng om ure poet This Book Will Teach You to Become ie TO DAY Recast eae OO. AO. hemetae tnd An Expert Automobile Repair man, not Stator Winding, Drafting, Auto, Track and Tractor Electricity, Battery Building and Repeiting. and only on testing, adjusting and repairing | Radio. Everything to make you thoroughl y trained, engines, carburetors, clutches, rear axles, BIG PAY, Electrical EXPERT. ° : . A

differentials, tires, etc., but an Electrical Expert on ignition, generators, starting mo- AT HOME tors, storage batteries, ctc. Diagnosing any | @ trouble will be easy. you can earn $1 to $2 an hour in your spare § - time writing show cards. No canvass- The Electrical Center — Order N , = ingor soliciting. Weinstruct you by our new § of thee World on t wait—Order Now: simple Directograph System, supply you with work and pay you cash each week. Write e whole world of electricity is open to the COYNE .00—Li i today for full part traned Electrical Expert. = toChicago—the Elec- Cloth $6.00 Limp American Morocco 4 eee aan eoes Socket. trical Center of the World. We pay your fare. Get $7.50 Postpaid WEST-ANGUS SHOW CARD SERVICE LIMITED your training at pe a a largest ond ae Scere & or aoa ag wonane i. school of practical electricity in the country—endor: 3 ‘oO rne Buildin oront . by Bleetrreal Industry. We do not offer a number of 6 S> ms °, an individual courses—we give you just one complete y= eee Pate a eo ee Eppert i of commanding big pay. You can become an er b ] and wet r=) mente in ANY branchof electricity i Automo le come to C:

Learn in 12 Weeks! Repairshop Shortcuts te te ae ‘ ¥ a ee ee Picture Not acorrespondence school. No books or useless the- A book for the repairman, with over 1,500 = entipins—~ Gala teaiden Peon

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Page 15

y,Mo. . Big of our sitions. ‘ears in d Con- New Shops. hanical ay and y, Mo. ——— ia secret easy. on any eacher. today. rk City con et or Money Making Opportunities AGENTS “Zio DAILY silvering mirrors, plating and refinishing lamps. reflectors, autos, beds, chandeliers by new method. Outits furnished. Write Gunmetal Co., Ave. F, De- eatur, Illinois. AGENTS—Write for free samples. Sell Madison “Better-Made” Shirts for large Manufacturer direct to wearer. No capital or experience required. Many earn s100 weekly and bonus. Madison Mills, 564 Broadway, New York. EVERYBODY Needs and Buys the “‘Business Guide.” Wells cleared $1150 in 35 days. Send for Sample. It’s Free. Nichols Co., Dept. 1B, Naperville, Il. AGENTS, Big money-making opportunity, selling Pure Silk guaranteed hosiery. Permanent business proposition. Mayville Knitting Mills, Mayville, N. Y. AGENTS Wanted—Something New—Fire fighter sells easily. Makes a spectacular demonstration; car owners, homes, factories, stores, practically buy on sight. Our men make $10.00 to $50.00 a day. If you wish to estab- lish a business of your own with unlimited possibilities for making big money, write us today. FYR-FYTER CO., 256 Fyr-Fyter Bldg., Dayton, Ohio. HELP WANTED MAKE Money at Home. You can make $1 to $2 un hour writing show cards at bome in spare time. No eunvassing. No experience needed. We instruct you and supply work. Dept. 27-M, National Studios, 6121 Dorchester, Chicago. PARN $10.00 to $35.00 weekly mailing circulars at home. Outfit and instructions 25 cents. Jamorris, 2305 Gratz, Philadelphia, Pa. DETECTIVES Earn Big Money. Excellent oppor- tunity. Travel. Fascinating work. Experience un- necessary. Write, George Wagner, former Government Detective, 1968P Broadway, N. v: SALESMEN. We pay larger commissions than any other Brush House in the Country to men selling our line of Sanitary twisted-in wire b es. Sanitary Wire Grip Brush Co., 15 Mercer St., New York. MONEY Polychroming, also Silvering Mirrors. Sample and particulars free. olychrome Works, 2604 East 40th, Kansas City, Mo. EARN $1.20 an hour cutting blanks at home; spare time. Men only. Send addressed reply envelope. Good- year Sm., 147 W. 23rd St., New York. BE a detective. Excellent opportunity to earn big money, travel, thousands of dollars offered in rewards. Established 1909. Particulars free. Write to C. T. Lud- wig, 424 Westover Bldg., Kansas City, Mo. SILVERING Mirrors, French plate. Easily learned; immense profits. Plans tree. Wear Mirror Works, Ex- celsior Springs, Mo. OUR genuine gold window sign letters are an excellent money-making proposition for handy men. Slann Sign System, East Bethune Avenue, Detroit, Michigan. EMPLOYMENT in South America. We furnish classified lists of 350 employers for $1. South America Information Bureau, Portland, Oregon. ALL men, women, boys, girls, 17 to 65, willing to accept Government Positions, $117-$250, traveling or station- ary, write Mr. Ozment, 295, St. Louis, Mo., immediately. DETECTIVES needed everywhere; cities, towns. Particulars free. Write National Detective System, 188 East 79th, New York. i FIREMEN, Brakemen, Baggagemen, Sleeping car, train porters (colored). $140-$200. Experience un- necessary. 838 Railway Bureau, East St. Louis, Ill. WRITE photoplays; $50 each. Experience un- a vi guaae free to beginners. Producers’ League, 2, St. Louis. STOP Daily Grind. Your town needs plater operutor. There’s money silvering mirrors, headlights, radiators, bumpers, stoves, tableware. Reliable outfits furnished. Here's help Free. Sprinkle Plater, Dept. 98, Marion, Ind. " MEN—Experience unnecessary; , travel; make secret investigations; reports; salaries; expenses. Write Ameri- can Foreign Detective Agency, 321, St. Louis, Mo. RAILWAY Postal Clerks—Start $133 month. Rail- road pass; expenses paid; questions free. Columbus Institute, N-2, Columbus, Ohio. RAILWAY Mail, Postoffice Clerks, Carriers, Customs and many other positions a ee yearly Write today for 36 e booklet showing how to obtain one of these desirable life positions. Chicago Civil Service College, T-70 Kesner Building, Chicago. BUSINESS OPPORTUNITIES BECOME A Foot Correctionist. A New Profession, not medical nor chiropody. All the trade you can attend to; many are making $3000 to $10,000 yearly, easy terms for training by mail, no further capital needed or goods to buy, no agency or soliciting. Address Stephenson Labora- tory, 10 Back Bay, Boston, Mass. MOVIES: With the one in your neighborhood you can operate a good paying business without capital or experience. Complete instructions and information 25c. Nothing else to buy. Address your order to D. P. O'Donnell, 215 Southy Ave., Altoona, Pa. : I MADE $100,000 As Real Estate Specialist. Free information tells how. American Business Builders, Dept. 4348, 1133 Broadway, New York. : SUCCEED with your own products—Formulag, Processes, Trade-Secrets. Different, dependable, profit- a je. Catalog free. C. Thaxly Co., Wash., D. C. f :O into business for yourself. Make money marketing proprietary specialties under your own labels. We furnish everything and show you how. Booklet free. National Scientific Laboratories, 224 Monroe, Richmond, Virginia. x \ BUSINESS offering larger returns than usual lines. £100 starts you. Dept. R, Paul Kaye, 149 B'way, N. Y. z A WASHINGTON, D. C., office will dignify and in- pees 7 your business. Use ours. Expense, small; benefits, srea*. Capital Service Company, 632 Pennsylvania Ave., MANUFACTURE your own Beauty Clay. Send 29¢ for original $50.00 formula. Valley Laboratories, Wilmerding, Penna. $20,000.00 YEARLY. State distributor. Amazing : wly invented Pricing System, retails $4.90 only. No mpetition. Tremendous demand!! Millen Mfg., Dept. \. T., Colonial Bldg., Boston, Mass. ,\RE you old at forty? See our advertisement on page \00 of this issue. The Electro Thermal Company, 4036 fain Street, Steubenville, Ohio. More Money Making Opportunities on pages 4 to 17 * POPULAR SCIENCE MONTHLY ~Fasily : New Self-Massaging Belt Makes You Look Many Pounds Lighter and Inches Thinner the Moment You put It On—While Actual Fat Disappears as Quickly and Surely as ough Under the Hands of an Expert Masseur. No Dieting—No Drugs—No Exercise. WONDERFUL new invention that not only gives you an instant appearance of slimness— but actually reduces your bulging waistline to norma! in an amazingly short time—is now being used by thousands of men who were formerly over- burdened with an excess of fat. With this remarkable discovery it is no longer necessary to resort to heart-straining exercises or wedkening diets—and few men can take the time or pay the exorbitant fees charged by the professional masseur. Gets Same Results as Expert Masseur As every one knows, the masseur, by skillfully manipulating the loggy tissues right at the spot, sets up a vigorous circulation that seems to literally melt the surplus fat away. The Weil Scientific Reducing Belt operates on exactly the same principle. Made of specially pre- pared and scientifically fitted rubber, it not only reduces your waistline as much as 4 to 6 inches the moment you put it on, but is so constructed that every movement you make, every breath you take, imparts a constant, gentle massage to every inch of your abdomen. It massages away the abdominal fat so quickly and easily that it seems almost like magic. In a few weeks inches and inches of fat should actually disappear. Endorsed by Physicians and Athletes Thousands of men who were formerly burdened with bulky, disfiguring fat have not only vastly improved their appearance at once with the Weil Reducing Belt, but have quickly acquired a normal waistline in this easy, pleasant inexpensive way. It is the choice of hundreds of athletes and jockeys. Physicians everywhere endorse it because it not only actually takes off fat, but corrects stomach disorders, constipation, backache, shortness of breath and puts the sagging internal organs back into place. Satisfaction guaranteed or your money back without question. Mail the coupon at once for full description and special Reduced Price Offer. Address THE WEIL COMPANY, 108 Hill Street, New Haven, Conn. 15 Bulging Waistline Reduced As shown above, every move of your body walking, climbing stairs—merely breathing as you sit— causes the Weil Belt to massage your abdomen, it is working every second to remove your fat. mee eH + FH THE WEIL COMPANY, 108 Hill Street, New Haven, Conn. | Gentlemen: Please send me, without. obligation, 1 complete description of the Weil Scientific Reducing 1 io and also your Special 10-Day Reduced Price 1 Offer. Name 1 PE intininiinitinenintnvanasdannanaa ee l I ale asi Rae's deh’ cia RGL Seat alert State.....-. The New Tinsmith Helper and Pattern Book By Hall V. Williams A handbook giving a practical ex- planation of simple geometrical prob- lems, the forming of seams, laps and joints, and one hundred problems on the layout and cutting of conical vessels, elbows and piping, furnace fittangs, ducts, gutters, leaders, and roofing, unclad fire- proof doors, cornice and sky-light work with 165 tables and many shop kinks, recipes, etc. 428 pp. 248 Illus. $3.00 Popular Science Monthly 225 West 39th Street New York City The New Metal Worker Pattern Book By George W. Kittredge A complete course of instruction in the modern methods of developing and cutting patterns for sheet metal work. The principles underlying practically every problem that is likely to come up in the practice are clearly explained. In this new and revised edition a series of automobile patterns have been added. These include problems in laying out guards, fenders, cowls, skirts, hoods and other automobile parts. 514 pages, 9 x 12 inches, 895 figures, cloth $6.00 Popular Science Monthly WANTE RAILWAY MAIL CLERKS 225 West 39th Street New York City $1GO0O0to$S2SOOaVear Ske EES. n. MEN—BOYS 17 OR OVER SHOULD Steady work. Common Education Sufficient: TRAVEL—SEE YOUR COUNTRY 3s Sirs: Send me without charge: (1) sample Rail- > way Mail Clerk Examination questions; (2) List © of U.S. government jobs now obtainable; (3) Send MAIL COUPON IMMEDIATELY > free illustrated book,**‘ How to Get Government Jobs.”” No layoffs. Paid Vacations ©

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16 are) coin T TAKES but a moment— to mark the career of your choice, sign your name, clip out and mail this coupon. Yet that simple act has started more than two mil- lion men and women toward success. In city, town and country, all over the world, men are liv- ing contented lives in happy, prosperous homes — because they clipped this coupon. In every line of business and industry, in shops, stores, offices, factories, in mines and on railroads, men are holding important positions and re- ceiving splendid salaries be- cause they clipped this coupon. You, too, can have the position you want in the work you like best, a salary that will give you and your family the home, the comforts, the little luxuries you would like them to have. No matter what your age, your occupation, your education or your means—you can do it! All we ask is the chance to prove it. That’s fair, isn’t it? Then mark and mail this coupon. There’s no obligation and not a penny of cost. It’s a little thing that takes but a moment, but it’s the most important thing youcan doto-day. Doitnow! Mail It To-day for Free Booklet ~ INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7603-D, Scranton, Penna. Without cost or obligation on my part, please tell me how I can qualify for the Y ees or in the subject defore which I have marked an X: BUSINESS TRAINING COURSES Business Management (J Salesmanship Industrial Management Cj Advertising Personnel Organization Ey show Letters =B & Traffic Management Show Card Lettering (Business Law Stenography and Typing (jBanking and Banking Law Business English (Jj Accountancy (including C.P.A.) () Civil Service Nicholson Cost Accounting allway Mail Clerk Bookkeeping Common School Subjects span Secretar High School Subjects Spanish Q French Llustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering Architect Electric Lighting Architects’ Blue Prints Mechanical Engineer Contractor and Builder Mechanical Draftsman Machine Shop Practice Railroad Positions Structural Engineer Gas Engine Operating Chemistry (1) Pharmacy Civil Engineer Automobile Work Surveying and Mapping Fy Agricul Engines Architectural Draftsman Concrete Builder Metallurgy O) Mining Agriculture and Poultr Steam Engineering 0 Radio Mathematics r SNE Ee cass Pedloeb dpi taionch cbs socnnctasessiouvesepaciarbuauscucee nbbinbtsenscascsyses Street 3-6°24 ND eS CCR i caccd ueei ea ieudseseecceceubswuscsucsnensmeeeasribeerssbers aiuto IID a2) ics cicusancateconsescvonhvoestassiaconsssesesetAces Persons residing in Canada should send this coupon ‘to “the International Correspondence Schools Canadian, Limited, Montreal, Canada POPULAR SCIENCE MONTHLY I Train You to Boss the JOB! a Week! Let me | Tare et Train nst uction right at You @ home covers Bl: branch auto work, Me! you for Ex: ’ work and salaries of Pid oo $200 a week. W. COOKE 8 directing Engineer of the big Directing Engincer. Chicago Auto, enope succeed and I GO INTO BUSINESS! tmake $5000 0 $19,000 a9 ar I TN pe oe training you need to in their own business. Greatest opportunities to make big money in upkeep end of auto business, 2 Big testing and repair outtits free to my students. AUTO BOOK FR si Pe a a foformation; specin s offers and big B. ¥ 4° 89 free. today—addr« me persona 1 COOKE, "Direcue Engineer. CHICA GO AUTO SHOPS, Dept. C25. 1916 Sunnyside Ave., Chicago Course for men of : mbi- s b Electrica tion and limited time. Over 4000 men tr ined. Condensed course in Theoretical .nd Practic:] Elec- il the close- tric: Engineerin lyrelated subjects of Mathematics and Mechanical Drawing taught by experts. Students construct motors, install wiring, test electrical machinery. Course complete In One Year Established in 1893. Prepare for your profession in the most interesting city in the world. Free catalog. BLISS ELECTRICAL SCHOOL 102 Takoma Ave. Washington, D, C. sncteting STUDY | AT HOME Begone law Legal icne an opportunities before. Be independent—be a - $3,000 1 r. Lawyers Lg eae 0 Ann ually Vora eg dn you etep 4 me My letters from pare, SEnlio etsda various states. De; sands of successful studen' Low cos' ome rma + ry, a ea text! material including fourteen: ur valuabl -page iw vole Evi fae LE books FREE. Send for them--NOW- LaSalle Extension Sateen, Dept. 883-L, Chicago 4 NNOANNRARRANNNAAAAAAAAAADAAADN NANA Learn at Rome ¢ to mount birds, ani- robes.” Complete lessons a Easily and @ulraly any learned by men, spore Ss a —_ rite for Free Taxidermy Book. Tells all aooee it. y sportsman, trappe: Nature lover a now this fw — 1? Save your t& Bi tig RLS oe apace bee Write for yng Neb. Northwestera sani Tazidermn; C-178 Elwood Bidg., Omaha, Written For The Latest Fox-Trot Ballad Entitled “LL BE WAITING” Those wishing to compete for this prize, write for Free Copy of song and contest rules EQUITABLE MUSIC CORP., 1658 B' WAY. New York # - Earn $75 to $200 | ARITHMETIC oF ELECTRICITY A practical treatise on electrical calculations of all kinds reduced to a series of rules, all of the simplest forms, and involving only ordinary arithmetic. 200 pp. ice, $1.50. POPULAR ges MONTHLY Books on Electricity The Electrician’s Wiring Manual By F. E. SENGSTOCK, E. E. Contains all the information needed for the proper installation of lighting and power systems in houses and other buildings. It completely covers inside elec- trical wiring and construction in accordance with the National Electrical Code. Pocket sise—flexible binding 448 pp. Price $2.50 Construction of Small Al- ternating Current Motors By PROF. A. E. WATSON Brown University This book contains complcte instructions for building small al- ternating current motors in several sizes. The designs will be found in harmony with those of the very best manufacturers and they can be worked out by the amateur for making useful instruments. Fully Illustrated. Price, $1.50 Experiments With 110- Volt Alternating Current By J. D. ADAMS Here at last is a book that devel- ops a practical working familiarity with the alternating current—the form in which electricity is used in every home. The author shows how this can be done in an inter- esting and inexpensive way. 256 pages, 135 illustrations. Price, postpaid, $1.75 How to Make Things Electrical This book gives directions for making hundreds of electrical appliances. and devices for the home, the shop and the garage. The simple directions and many drawings make the work easy. 429 pp. Price, $1.59 postpaid POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City é - ‘ é ¢ ; Regt e BS

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—_ ~~ Va we

ig RATT RONG ROEM RC 7 q 4 5 f

——> eine mel aren noe am —just ready ey give informae ~—S = in oer ig Se lasterers, lile Setters — ali Cement W Workers. Easy to use, showing 2067 il- F. S. Quaker Stamp Co., Toledo, Ohio. NEWFOUNDLAND Stamps sent on approval. Butler, St. Georges, Newfoundland. ALL different, 300, 25c; 500, 50c.; I'red Onken, 630 78th Street, Brooklyn. RARE Coins, Medals, Paper Money. United States, Forcign and Ancient. Old Coin and New Catalogue 10c. Alexis Mengelle, Box 387, Colorado Springs, Colo. BAVARIA, 50 varicties, 10c. Germany, 50 varieties, 7c. George, 985 Seventh St., Milwauke e, Wis 100 RARE stamps, all different, Garesin lists, Stamp

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Magazine, everything 7c. Stanton, Niantic, Conn. REE 25 1 rent U. S. stamps with 60% approvals. 45 different U. S. 10ec. Seidenberg, Merton, Wis. Ee German Marks $1.00. Rivers Hicks Kentville, Nova Scotia. NYASSA Giraffes and packet of 52 different scarce stamps, Fiume Triangle, large, $1.00 U. S. Rev., milli- metre scale, perforation gauge and ruler for only 9¢ To introduce our Sudden Service approvals. Fennell Stamp Company, Dept. C. Fullerton Bidg., St. Louis, Mo, More Money Making Opportunities on pages 4 ioI5

$2500 REWARD For the Capture of An Unknown Man WICE he had entered the St. Clair Mansion. What was he after? Who? What was in danger? Berteau, the famous detective, had warned St. Clair that the mysterious marauder would come again. And now —a noise in the ‘passage! The creak of an opening door. A shot in the dark! A capture! Is this wounded stranger the mysterious in- truder? Whocouldtell? Yet Berteau identi- fied the man without hesitation and won the $2500 reward. How did he do it? Easy enough for the Finger Print Expert. Heis the specialist, the leader, the cream of detectives. Every day’s paper tells of their wonderful exploits in solving mysterious crimes and convicting dangerous criminals. More Trained Men Needed The demand for trained men by governments, states, cities, detective agencies, corporations, and private bureaus is becoming greater every day. Here is a real opportunity for YOU. Can you imagine a more fascinating line of work than this? Often life and death depend on finger print evidence—and big rewards go to the expert. Many experts earn regularly from $3,000 to $10,000 per year. Learn at Home in Spare Time And now you can learn the secrets of this science at home in your spare time. Any man with common school education and average ability can become a Finger Print Detective in surprisingly short time. Free Course in Secret Service For a limited time we are making a special offer of a Professional Finger Print Out fit, absolutely Free, and Free Course in Secret Service Intelligence. Mastery of these two kindred professions will open a brilliant career for you. Write quickly for fully illustrated free book on Finger Prints which explains this wonderful training in detail. Don’t wait until this offer has expired—mail the coupon now. You may never see this announcement again! You assume no obligation—you have everything to gain and nothing to lose. Write at once— address University of Applied Science Dept. C-136, 1920 Sunnyside Ave., Chicago, Ill.

UNIVERSITY OF APPLIED SCIENCE 4 Dept. C-136, 1920 Sunnyside Ave., Chicago, Ill. J Gentlemen:—Without any pre Ty whi atever, ij send me your new, fully illustrated, ZE book on ! Finger Prints and your offer of a F RE E course in i Secret Service Intelligence and the Free Profes- sional Finger Print Outfit. Py 4 CT CU a Fa ci Wicca i aa ae a ser ae nok cag Dn s | BONE Sos ec detncedocdesenandensananmacs

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POPULAR SCIENCE MONTHLY More Power to Your Radio Set! Fill the room with radio from distant stations without changing your set. or ASSP I SS ERR Ee meme murrerpaRtemteem ae MANE Simply plug in the Music Master Power Unit between your set and the reproducer, and enjoy stronger and better radio. Thus you will have loud-speaker volume from a one-tube receiver, or greatly increased vol- ume from a larger set. j In shape and finish the Power Unit is specially adapted to form a base for the “eI Music Master Radio Reproducer. Oper- I L ates from the ‘‘B”’ batteries of your set. f ‘“‘A”’ batteries come with Power Unit and d \ | | are mounted inside. f i ; Don’t discard the small set—amplify it. Let your radio dealer show you the re- ‘ ; markable results that may be obtained from a combination of the Music Master | 4 one Power Unit and the Music Master I Reproducer. ; © U f Sy. {lusic Master Corporation ’ Makers and Distributors of High-Grade Radio Apparatus a 7 Cte es ae 10th and Cherry Streets ‘ ti RS tf re “4 Chicago PHILADELPHIA Pittsburgh q S , n E Music MASTER : RADIO REPRODUCER e ik Mt tr he $30 : : t] i Meld or Ow $35 ? Music MASTER POWER UNIT - 4 4 0 : fc including batteries but without tubes $50 POWER UNIT

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: E 5 a MW AX How the Institute Tests Tools POPULAR SCIENCE MONTHLY ‘ BU mz rejected by the Institute. Three wrenches subjected to the hardness tests by the “‘Brinell” machine (at the right). The smallest tool was too brittle; the center one too soft. The largest wrench passed the tests. Both were Note the circular indentations caused by pressure of a super-hardened steel ball By Collins P. Bliss, M.A. Director of the Popular Science Institute of Standards N OPEN-END wrench that sells A for 10 cents looks the same as a wrench that sells for 30 cents. But looks are only “skin deep.” It is what is under the finish that determines whether a wrench, or any other tool, will stand up under the wear and tear of everyday use. Usually the only way a layman has been able to tell whether a tool will do the work for which it is designed has been by actual use. But now, by buying tools that have been approved by the Popular Science Institute of Standards, the lay- man is assured of satisfactory service. Before the Institute approves a tool it is subjected to severe laboratory tests and critical examination by the Institute’s engineers. In the case of an open-end wrench, for example, the first test is the hardness test. Such a tool may be made of steel so soft that its jaws soon would become deformed. On the other hand, the steel might be so brittle that strong pressure on the wrench would break the jaws. Somewhere be- tween these two extremes of hardness and softness is a happy medium that is ideal for the manufacture of tools of the highest quality. NCLUDED in the $300,000 worth of testing apparatus available in the laboratories where Popular Science In- Stitute of Standards’ tests are conducted, are two ingenious machines that are used to determine exactly the hardness of tool metals. One is called the “Brinell’’ Test- ing Machine; the other, the Shore sclero- scope. In the “‘Brinell’’ machine the wrench is placed so that a super-hardened steel ball rests on the spot to be tested. The ball is pressed into the metal. The depth to which it can be pressed provides the basis for calculations showing the hardness of the metal. ia THE indentation near the jaws of the wrench is too great, it is obvious that the steel is too soft. If the indentation is not sufficiently great, the steel is too hard and brittle. In either case the tool is z . ad F © 7 POPULAR SCIENCE Monthly @uarantee The above seal on an advertisement indicates that the products referred to have been approved after test by the Popular Science Institute of Standards. Popular Science Monthly guaran- tees every article of merchandise advertised in its columns. Readers who buy products advertised in Pop- ular Science Monthly may expect that these products will give abso- lute satisfaction under normal and proper use. Our readers in buying these products are guaranteed this satisfaction by Popular Science Monthly. THE PUBLISHERS. 4 e) rejected by engineers of the institute. In the Shore scleroscope the tool is struck by a small diamond-pointed hammer falling freely from a height of about 10 inches. By measuring the re- bound of the hammer, engineers can deter- mine the hardness of the steel. By drop- ping the hammer on various parts of a tool, we can ascertain whether the steel on the edge, or near the edge, is hard enough to stand up under use, and whether the shank is not too hard for the proper toughness. These hardness tests are extremely im- portant in testing not only wrenches, but almost all tools. In a wood chisel, for example, if the metal is too soft, the edge soon will wear and the chisel will not cut. On the other hand, the steel may be so brittle that a slight force will chip the edge. Even in a hammer it is possible that the metal may be too hard or too soft. A saw requires varying degrees of hardness, ranging from very hard at the teeth to comparative softness in the back of the blade. Hardness is only one of the many quali- ties for which tools are tested before they are approved by the Institute. When you purchase tools approved by our engineers, you know that you have a product that is correctly designed and will withstand normal usage. Send for list of Approved Products POPULAR SCIENCE MONTHLY will be glad to furnish, upon request, a list of Radio and Tool manufacturers whose products have been tested and approved by the Popular Science Institute of Standards.

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yw POPULAR SCIENCE MONTHLY TRADE MARK REG.US. PAT. OFF, “A slight deviation leads to a great error.” — Confucius In tuning in the distant sta- tions there must be unfailing precision. The Grebe Ta- pered Grip Dial gives that precision. Coder Hy Grebe Regenerative Receivers are licensed under Armstrong U.S. Pat. No. 1,113,149, Oct. 6, 1914 HE first tuning dials were ungain- ly in appearance and crude in performance. Some years ago this company perfected the Tapered Grip Dial, moulded from lustrous black bakelite, that has since become stand- ard equipment on all Grebe Receivers. This and other details of Grebe craftsmanship are fully protected by patents granted and pending. Ask your Dealer or write us A. H. GREBE & CO., Inc. Van Wyck Blvd. - Richmond Hill, N. Y. Western Branch: 451 E. 3rd St., Los Angeles, Calif. Bes eee rear es ire

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_* rap POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor August, 1924 A Wonder House of Science By Raymond J. Brown When President Coolidge recently dedi- cated the beautiful new national home for sci- ence, opened at Wash- ington, D. C., by the National Academy of Sciences and the Na- tional Research Coun- cil, he declared that “the magnificent build- ing predicts a newdayin scientific research.’’ In the following article Mr. Brown tells of a visit to this great public shrine of knowledge and of the wonders he found available there to every American. FEW weeks ago I had the thrilling experience of vis- iting a modern house of wonders where science plays the host. This house of wonders is a stately building of creamy marble, pictur- esquely situated near the banks of the Potomac at Washington, D. C. It was erected and opened recently by the National Academy of Sciences and the National Research Council to provide science with a place to keep open house for its friends, old and new; to entertain them, thrill them and amaze them by a display of the marvels of nature and the newest discoveries of scientific workers. The place is neither museum, scientific labor- atory, nor theater. And yet it is all of these—and more. The glass cases for exhibits and the familiar warning ‘“‘Hands Off!” of the conventional museum are conspicu- ously absent. The exhibits are in plain sight, unguarded and unprotected. More, you and I, when we eall on Science in its new home, are urged and invited to handle the exhibits, to play with them and experiment with them as much as we please. Though they are made up in great part of the most delicate, intricate and expensive instruments of the modern scientific laboratory, they are no* reserved for the exclusive use of experts, One of the wonder rooms in the new home of science. Here you can make a chemical analysis of the sun, or at least detect the presence of iron in the sun. The visitor is seen looking through a spectroscope that splits up the sunlight into its spectrum in the basement below. Simply by pressing a switch, a spectrum of burning iron is projected on the solar spectrum, and the lines of the iron you can see sun-spots. as would be the case in a laboratory. You and I, whether we be scientists or merely casual sightseers at the national capital, are permitted to make free use of the ap- paratus. On every exhibit are attached plain directions, which instruct us how to turn the switches, to press the buttons, to focus the eye pieces. The purposes of the experiments are explained; we carry them on with our spectrum are seen to coincide with those of iron in the solar spectrum. On the disk in the center of the pedestal is projected an image of the sun on which At the rear is a swinging brass ball suspended by wire from the top of the 60-foot dome, over a brass plate on the pedestal that demon- strates convincingly the principle of the rotation of the earth about the sun own hands, observing the details of the succes- sive stages with our own eyes, and we appreciate the significance of the conclusion as we never could were we merely to read of it or to hear it discussed by a lecturer. No theater could provide aspectacle more amazing than this almost bewil- dering array of scientific wonders, made tangible and understandable to all who come to see. HIS new national home of science is an institution unique in all the world. Its founda- tion marks a tremendous forward step in the efforts of present-day scientists to convey to the average man an ap- preciation of the im- portance and purpose of scientific research. Scarcely had I stepped inside the massive bronze entrance doors, whose panels graphically depict the history of science from Aristotle to Pas- teur, when I was con- fronted by visible proof of a fundamental marvel of creation, yet one which, even in this en- lightened age, many per- sons undoubtedly accept largely on faith—the ro- tation of the earth about the sun. N THE center ro- tunda, suspended by a wire from the top of the 60-foot dome, a great brass ball was swinging slowly back and forth like the pendulum of a huge clock. On an ornamental pedestal just beneath it lay a brass plate, its surface ruled with fine lines radiating from its center. A pointer at the bottom of the oscillat- ing brass ball made it simple to pick out the line with the direction of which the movement of the pendulum coin- cided. I made note of the line along which the pendulum was swinging, but when I re- turned to the rotunda several hours later, JA

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22 the pendulum was no longer following that line. It was moving along another line at an appreciable angle to the direc- tion of the first line. Apparently the swing of the pendulum had changed. But actually it had not. The direction of its oscillation was exactly POPULAR SCIENCE MONTHLY which we are frequently and more or less unpleasantly reminded these days when almost everybody is interested in radio, is atmospheric electricity. We realize that the air is full of electricity every time static crackles in our earphones or loud- speaker and interrupts the radio program we have been en- = joying. Just across the way from the seismograph, on the other side of the entrance hall, I found an instru- ment that registers and measures the amount of atmos- pherie electricity quite as readily as you would check up the voltage and amperage of your radio or automo- bile storage bat- Front view of the Wonder House of Science, Washington, D. C., erected at acost of $1,450,000, and dedicated to promote popular interest in science tery. Alongside of this was an instru- the same as when I had ob-_ f[- served it first. What had happened was that the earth had turned beneath it! “VEN before observing ~ this pendulum for the first time (scientists call this apparatus the ‘“‘Fou- cault pendulum’’), I had been brought face to face with the fact that there are many amazing things about this earth of ours that most of us, plodding along about our workaday affairs, recall quite as infrequently as we do the fact that our seem- ingly stable earth is con- tinually whirling through space. There is the matter of earthquakes, for example. Ordinarily we hear only of the great disasters, such as the one that occurred last year in Japan, but earth- quakes happen rather fre- quently—10,000 times a year, once at least every hour, according to the latest testi- mony of the scientists. There was graphic evidence of that fact on the broad record- ing tape of the new type seismograph that was the first thing I saw when I entered the building. Here and there on the paper roll clicking through the machine were jagged breaks in the straight line that the recorder ordi- narily describes. Each break was the record of an earthquake that had occurred somewhere in the last few days. They were small quakes, mere tremors, as I could see by comparing them with the record of the Japanese disaster, framed on the wall behind the instrument; yet they constituted a reminder that our “solid” earth consists merely of a shell surrounding a comparatively soft core: and that the outer covering is likely to break and slip at almost any time. There is a strange fascination in watching this instrument—waiting for an earthquake to occur so that you may see its vibrations. Another phenomenon of nature, of In these glass cases you can see how science grows plants by electric light. artificial light, are taller and sturdier than those of the same species at the right, grown under natural sunlight The plants at the left, grown under ment called the ‘‘magnetograph,”’ which records the presence of elec- tricity inside the earth, and clearly demonstrates that our earth is actually a great magnet. HERE is a definite connection between the facts that these in- struments reveal. Both the earth and the air above the earth get their electricity from the sun, which, scien- tists say, is continuously bombarding us with a storm of electrons. Sometimes the surface of the sun bursts forth in great whirling eruptions. From these the bombardment of electrons pours out with a new intensity. The terrific electric hail is hurled against the upper strata of the earth’s atmosphere. Then we see the aurora borealis. Terrestrial electricity increases correspondingly with the usual activity of the sun, often to such an extent that telegraph communication is inter- fered with. Once it even burned out an ocean cable. These instruments—the magnetograph and the electrograph—scarcely more re- markable in appearance than a small telescope, record the causes of these amaz- ing phenomena. Marvelous instruments, you will probably say, as I did. But only a few steps away from them can be seen a still greater marvel—the cause, the actual source of the phenomena—the sun itself. (>* THE pedestal in the center of the rotunda above which the Foucault pendulum moves slowly back and forth is a white disk—eight inches or so in diam- eter. From the dome above a bright beam of light plays on this disk, illuminating its center with a dazzling circle of light, six inches across. This circle is an image of the sun, ingeniously projected on the table by mirrors and a lens in the dome. Examining this closely I saw several faint specks. They appeared as if they might be streaks on the white disk, or the images of dust spots on the surface of the lens above. Actually, though, they were images of the eruptions in the sun from which the rain of electrons pours on the earth. Sun-spots, astronomers call them, mysterious vor- tices of fiery gases that exert a profound influence on our weather and climate. Watch them for a few minutes, and they seem stationary and unchanging. Come back the next day, though, and the form of the spots has changed and their positions have shifted, for the sun is rotating even as our earth is. That pedestal I found a veritable wonder box in it- self. At one side of it was An every-day wonder of the microscope— How the figure 2, written in ink on a plain piece of paper, appears when highly magnified an eye piece. Looking through this I saw the beautiful spectrum of the sun with its seven colors, one melting into the other through intervening shades that made it difficult to say where one color ended and the next began. This spectrum is produced by permit- ting light from the solar image on the pedestal to pass through a narrow slit to an optical grating at the basement floor where the white light is resolved into its component colors and transmitted back as the spectrum. ~—-—A Mer .I - © a fF A of BD & wm or a+ th fh of 2 eo Go oO ee a ee ee —

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ea aS ere n Tenn h ARAN ts Across the spectrum I saw innumerable dark lines. These lines are caused by the glow of the different chemical elements present in the sun. It was through these, by means of the spectroscope, an instru- ment similar to the one through which I was looking, that scientists were able to make chemical analysis of the sun, and later of the stars. HE dark lines I saw in the spectrum seemed all the same. Yet they differ widely, as I was soon to see. Touching an electric button near by, I started an eiec- tric arc, causing its iron poles to vaporize. The light from the burning iron descended through the slit beside the light from the sun. The light lines of this iron spectrum coincided with certain of the dark lines in the solar spectrum, demonstrating the presence of iron in the sun. Could I have projected the spectra of other chemical elements on the solar spec- trum, their lines would have coin- cided with other dark lines there, Light from a pocket flash travels around a corner. Here is a spectacular demonstra- tion of the amazing light-conducting quali- ties of clear fused quartz, a substance 65: per cent more translucent than glass, recently developed in commercial quantity. Samples of the quartz in various stages of manu- facture form one of the interesting exhibits indicating their presence in the sun also. In all history, probably, no wonder of science has taken such swift and violent hold of the public fancy as radio. And so, of course, in the new home of science there is a radio exhibit. However, it is nothing like any radio exposition you ever saw. You look in vain for the receiving sets and parts—loudspeakers, storage bat- teries, and similar apparatus. Here the fundamentals of radio make up the show. You are shown, in short, Just what radio is all about—exactly the things you ought to know if you’re really Interested in radio, but the things you probably never think about when you tune in to listen to broadcasting. You've heard of a man named Faraday, imagine. You probably know that he was one of the great pioneers of electricity. POPULAR SCIENCE MONTHLY But did you know that it was Faraday who first conceived the possibility of wire- less—using the ether as a medium of electrical transmission? Stepping from the rotunda into the radio room that adjoins it, I found ap- paratus all set up for me to perform one of Faraday’s epochal experiments, an ex- periment that led to the principles on Would you like to see how your voice sounds? Simply speak into the telephone transmitter of this remarkable instrument, press a button, and the sound waves of your voice are con- verted into light waves that flash across the glass screen shown in the center of the picture which radio and virtually all practical use of electricity today depend—a demon- stration of the generation of magnetic lines of force by an electric current. I pressed a button. Immediately the flow of electric current transformed what had been merely a coil of wire into a mag- net. I released the button, and the mag- net became merely a coil of wire again. Moving this coil about near another mag- net, produced an electric current, a fact that I verified at the next table. Simple experiments, both of these; yet to what startling things have they led! Here, too, I saw the development of the vacuum tube by successive stages, and the founda- tion of radio telephony. I observed the beautiful effects produced by making an electric discharge through gases, the pas- sage of electrons due to heat, and the action of a commercial vacuum tube. I was permitted also to exhaust a vacuum tube. Then, too, I saw how my own voice sounds. That may sound absurd, yet here was an instrument called the “‘oscillo- graph” that converts sound waves into light waves and makes them visible—an instrument through which scientists were able to analyze human speech and so per- fect the telephone, the radio headset and loudspeaker. PRESSED a switch and spoke into a telephone. Immediately, across a glass screen, passed an irregular flash of light. It persisted while I spoke, and stopped when I was silent. The flash re- sembled the markings on a phonograph record, greatly enlarged, which is scarcely remarkable inasmuch as the markings on a phonograph record are sound waves 23 converted into visible scratches instead of into flashes of light. On a similar prin- ciple—the conversion of waves in one medium of transmission into waves of another medium—are based the tele- phone, radio and television, the trans- mission of pictures and distant scenes. Perhaps you know of the interferom- eter, the marvelous instrument devised by Professor Michelson of the University of Chi- cago, who is president of the National Academy of Sciences, by which the distance, the diameter, and similar amazing things about the heav- enly bodies have been learned. Professor Mi- chelson has placed not one but three interfer- ometers on exhibition in the science building. I say ‘‘on exhibition” pur- posely. Like everything else there, they are yours to use and experiment with if you wish. The difficulty is, though, that one must be an astron- omer or a physicist to employ these instruments for their true purpose. There is a little apparatus only a few feet away from the interferom- eters, however, that any one can use. It is the invention of the late Prof. Ernest F. Nichols, of the Nela Park Laboratory, Cleveland, Ohio, and it illustrates one of the newest discoveries of science—the pressure of light. When a beam of light falls on you, it exerts a pressure against you just as if some one were to push you. The pressure is so faint that you cannot detect it, but science has shown that the fierce light that beats on the earth from the sun ex- erts considerable effect on the gravita- tional influence between the two bodies. In certain stars the pressure of light is so intense that it causes them to expand and tends to disintegrate them. It also is the force that pushes out minute particles to form the tails of comets. yo I lighted a small electric lamp at the rear of the table holding this apparatus, a narrow ray was thrown against a glass scale before me. Then I pressed the switch controlling a larger lamp. The ray from this, striking the first ray at an angle, bent it from its path, a fact that was plainly discernible in the movement of the ray across the scale. In the June number of POPULAR SCIENCE MONTHLY I told of the extraor- dinary properties of radium, the wonder element. In this new home of science you can see the wonders of radium yourself. Just across the hallway from the appa- ratus that demonstrates the pressure of light is a machine known as the Wilson- Shimizu apparatus. When you peer into an eye piece, you see a wonderful display of pyrotechnics in miniature—lightning- like flashes, a myriad of sparks, tracks of dazzling flame. It is as if you were watch- ing from a vast distance a nighttime bombardment of a city by a mile-long line of field guns. These tiny but energetic flashes are the alpha and beta particles shooting off from a bit of radium against a fluorescent screen (Continued on page 1!'

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2A Nature’s Super-Power Plant | Surprising Facts about Lightning and ac By George M. Ogle American In- of Electrical Engineers HERE has been much talk re- cently of super-power. Emi- nent engineers have estimated that 80,000,000 horsepower in elec- trical energy could be produced by utilizing fully the water resources of the country; energy equivalent to that contained in 800,000,000 tons of coal, or 200,000,000 more tons than the total annual product of the mines of the United States. Now, though the day of super- power is still far away, though the harnessing of all available streams in the country probably will remain for years merely a dream of imagina- tive engineers, it is altogether likely that most persons in the United States many times in the last few months have observed manifestations Associate Member, stitute POPULAR SCIENCE MONTHLY How to Avoid Danger During a Thunderstorm 1. Don’t stand under a tall tree with thick foliage. 2. Don’t stand up in an open field or on a beach. Lie down. 3. Don’t stand near chimneys. 4. Don’t be afraid of your radio apparatus, but be sure to disconnect it and see that it is thoroughly grounded. 5. Don’t allow cattle to collect under a tree or near a wire fence. 6. Don’t seek safety in a building with a metal roof and wooden pillars. 7. Don’t neglect to protect your home and other buildings with lightning rods if they are the only ones in the vicinity. 8. Don’t fear for your home if it is among others in a city block. It is quite safe. At the left: A spec- tacular demonstra- tion of an artificial lightning flash pro- duced in the labora- tory of the late Dr. Charles P. Stein- metz, world famous electrical engineer. Doctor Steinmetz is at the extreme left of electrical energy compared with which the 80,000,000 horsepower visioned by the prominents of super-power seem weak and feeble. For every time there is a severe thun- derstorm Nature discharges more elec- tricity in the form of lightning than the total amount that could be produced by the simultaneous use of every generator, battery, and static machine that has ex- isted since the dawn of electrical know- ledge. N EVERY single flash of lightning you see is concentrated many times more energy than could be produced in an instant by all the electrical generating plants in the world. The present avail- able electrical power in the world is about 10,000,000 horsepower, while the energy released in 1/200,000 of a second by the average flash of lightning is 250,000,000 horsepower—more than three times as much as engineers say they could develop by harnessing every stream in the United States! Lightning is Nature’s greatest show, and for many persons their supreme source of terror. The awe-inspiring mag- nificence of a large dis- play of lightning is in- escapable, but the terror of lightning pro- bably can be traced to its mystery and to the resounding roars of thunder that accom- pany it rather than to its actual danger. Re- cent scientific research, however, has succeeded in stripping much of the mystery from the phenomenon and has unearthed reassuring facts that should allay much of the fear oc- casioned by violent electrical displays in the heavens. Considering the enormous energy of a single bolt of lightning, it is surprising that there is comparatively little reason for man to be afraid of it, yet this state- ment is well substantiated by statistics. It is true that lightning is the sixth most frequent cause of fire in the United States. Latest reports of the United Your Safety States Weather Bureau show that it results in an average annual loss of more than $12,000,000, of which more than $1,000,000 is in the state of Illinois, with Texas second and New York third in the list of states that suffer most. ET as a cause of death it is ex- ceeded greatly by virtually every disease and every common form of violence. Only 425 persons were killed by lightning in the United States in the last year for which statistics are available, as compared with 1,038,952 deaths from all causes. The figures show that you are far more likely to die in a railroad wreck, to be killed by an automobile, to drown, or even to be murdered, than to die by lightning. Science has determined further that not more than one flash in 100 actually is dangerous either to man or property, simply because only one flash in 100 reaches the earth. The rest are spectacular discharges between clouds, followed by startling roars of thunder, but so far up in the air as to be quite harmless to any- thing on earth. Moreover, only a small percentage of the flashes that reach the earth actually causes damage, for lightning, like every other form of electricity, GE + aia , An unusual photograph of a thunderstorm at sea, showing lightning flashes playing about the masts of a sailing vessel. While steel steamships are practically immune from lightning, wooden ships, especially those with masts, are places of danger travels over the path of least resistance; and, since air is not a good conductor of electricity, lightning, when it can, leaves the air to travel to the earth over some better conductor. Nowadays it is likely to find such a conductor in the form of a lightning rod, the steel frame of a city building, a metal flag pole or a grounded SGC a abated REA radi are har! con anil woo act M by one dan ning har1 on stee talle wor targ beer with the ning the : aye seve that top grou self of tl ning ume stru seve dam only it ¥

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ance; or of aves some ikely m of . city nded : carts ERNE mR RR I cm 0 OIE ES NARI radio aerial. At such times the chances are that the lightning will prove quite harmless. Only when it finds a better conductor than the air in a man, an animal, a tree, a frame building, or the wooden masts of a ship does lightning actually cause fires or the loss of life. graded of the exceptionally tall struc- i tures in the world have been struck ~ by lightning more than once, but have escaped POPULAR SCIENCE MONTHLY skeletons conveyed the electricity into the earth as silently and harmlessly as electric current flows through an ordinary transmission line. Indeed, to be inside a skyscraper, or any other steel-framed building during a thunder-and-lightning storm is to enjoy security. A steel ship likewise affords safety. So does a loco- motive or a railroad train. A frame building properly protected 25 appreciably if you will lie flat on the ground or in the bottom of your boat. If indoors during a thunderstorm, stay away from chimneys. Remember that lightning always is seeking the easiest path to the earth and the column of warm air ascending through a chimney is likely to supply it. A chimney also is likely to be lined with soot—carbon—a better conductor than the air; hence the path damage because the light- ning has been carried harmlessly to the ground on lightning rods. The steel Eiffel Tower in Paris, tallest structure in the world, hence an admirable target for lightning, has been struck many times without damage, despite the old adage that light- ning never strikes twice in the same place. Less than u year ago a lightning bolt severed the radio aerial that stretches from the top of the tower to the ground; yet the tower it- self was uninjured because of the protection of light- ning rods. The Washington Mon- ument. likewise has been struck by lightning on several occasions, but was damaged the first time only, in 1885, a year after it was built, and before Another spectacular photograph, taken at Indianapolis, Ind., lightning often is. adequate lightning protection had been Installed, Many of the skyscrapers in our cities ave been struck, without the occupants’ being any the wiser, because the steel Four tremendous discharges of forked lightning, flash- ing across the cloud-blackened sky simultaneously, are tecorded in this extraordinary photograph taken at illustrating how deceptive the appearance of Neither the building nor wires in the foreground was struck. In fact, not more than one in 100 flashes of lightning you see ever reaches the earth, and very few of these ever cause damage rr lA. ( AX 5 ~~ S a by lightning rods likewise is a place of safety. So, to a great extent, is a building in a deep valley. Any structure in the city, where buildings are in rows, is almost entirely safe from lightning. However, you may find yourself caught out in an electrical storm some day and you will want to know how to protect yourself. BOUT the most dangerous place in such a situation is under a tall tree with heavy foliage, especially if you are wet. The tree, a better conduc- tor than the air, attracts the lightning, which, vaporizing its sap and other moisture into a gas, causes an explosion, result- ing in serious injury or death to the person near it. Probably more people are killed by light- ning in this way than in any other. An open field, a beach, an open boat on sea, lake or river; the roof of a high building, the top of a mountain, or any other similarly exposed location like- wise is a place of especial danger. In any of these cases your body is likely to form the tallest conductor in your vicinity, and consequently the object most likely to be struck. If caught in an exposed place during a lightning storm, get under cover im- mediately if you can. If you cannot, you will reduce your chances of being struck Spokane, many times more energy than could be produced at one instant by all the power plants in the world Wash. In each flash was concentrated that lightning will take if it passes near by. There is an old tradition that it is dangerous to hold or be near any metallic objects while lightning is flashing. In the case of a wire fence, the metallic roof of a frame shed, or any metal object of similar size or larger, that is true. It is a good rule to keep cattle as well as your- self from wire fences. Much stock has been killed by huddling in fence corners during electrical storms. But to hold a penknife, a pair of shears, field glasses or an umbrella during a thunderstorm will not increase your danger. When the present widespread interest in radio began, many persons hesitated to install radio sets in their homes lest the aerials should “attract lightning.” This fear probably has been dissipated, for fire-department and insurance author- ities are agreed that an aerial, equipped with a lightning arrester, constitutes no source of danger. If properly grounded, it actually will afford protection by acting as a lightning rod. If you have a radio set, be certain, though, that you disconnect it during a storm and that your aerial is grounded. LTHOUGH the study of lightning and its effects has enabled science to frame rules for escaping its dangers, that does not mean that you are advised to emulate Ajax and defy the lightning to strike you. Rather, it is well to recall the fate of that mythical hero and take extraordinary precautions when lightning is flashing, for lightning has a way of playing freakish tricks, often with fatal results. (Continued on page 120

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off the coast of Ecuador on the equator, lies a tiny group of desert voleanic islands known as the Galapagos Archipelago—dots of barren lava land that still live in the Age of Reptiles! Here, among outlandish creatures that never have heard the voice of man, the dominant sound of life is the hiss of the sea iguana—a giant marine lizard that exists nowhere else in the world. The close-up photograph of this great reptile reproduced above is one of the amazing records brought back from Galapagos by a recent expedition led hy POPULAR SCIENCE MONTHLY » William Beebe, Director of the Depart- ment of Tropical Research of the New York Zoological Society. For 100 hours Mr. Beebe and his 12 fellow explorers searched islands that have been visited only by pirates, ex-convicts, and scien- tists. Charles Darwin visited four of the islands in 1835, and found wonderful material for his “Origin of Species.”’ The great marine iguana, Mr. Beebe tells us, grows to a length of four feet and looks like its prehistoric ancestors, some of which were 80 feet long. It lives about the seashore and feeds on sea- weeds. At night it sleeps in a burrow of Reproduced from “Galapagos: Werid’s End,” by courtesy of the author, William Beebe, and G. P. Putnam's Sons A Survivor from the Age of Reptiles ie THE Pacific Ocean, about 500 miles the earth, or in alava crevice. In the day- time it comes out, and at low tide makes its way to the edge of the surf to feed. Specimens of the iguana captured by the expedition refused all food. It was found they could live on salt water and air for more than 100 days. “No other living inhabitant of these islands seemed so thoroughly a part of its environment,” says Mr. Beebe. “In color, in rough contour, in the scales of its head standing up like volcanic cones, in its intimacy with lava and surf, it seems an organic embodiment of the shores of these desert islands.”

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day- rakes feed. d by | was - and these rt of “in les of 2ones, rf, it f the could travel to Mars and back in less than seven minutes! POPULAR SCIENCE MONTHLY It would take nearly 35 years for an airplane, speeding at two miles a minute, to travel from the earth to Mars; yet a radio signal Airplane distances to other planets, the sun and moon are indicated Could We Decode Mars Messages? By Lieut.-Comm. Fitzhugh Green, U. S. N. have been suggested to communi- cate with Mars this summer. Gigantic searchlights, long lines of blinking are lamps, geometric designs in the Sahara Desert, radio impulses of vari- ous kinds, huge reflectors for heliographic signals, enormous rockets, and other forms of pyrotechnics—these are but a few of the fantastic schemes proposed. Ordinarily Mars is between 100 and 200 millions of miles from us. But about once in 15 years she whisks by us in the night less than 36 millions of miles away. Her last visit was in 1909. This time it will be on August 22, 1924. To visualize this distance consider that an airplane flying two miles a minute would have to travel without stop for about 35 years to reach Mars, were such a trip conceivable. Our highest powered telescopes, how- ever, will shorten the distance visually to about 50,000 miles. This will enable as- tronomers to study the geography and the physical aspects of the planet’s surface. Martian geography is ahead of terres- trial geography. Though not until 1882 did we have our first map of Mars, we now know every inch of her polar regions while we are still exploring our own. Physical conditions on Mars are fairly well known. By the spectroscope we have learned that her atmosphere con- tains but the slightest traces of water. This fact is confirmed by absence of clouds about her. Everlasting ice-caps at her polar regions depict terrific cold. Shrink- ing of these caps toward Martian summer is taken as a sign of melting. That the "Tove beon 2 different methods N AUGUST 22 the planet Mars will be within 36,000,000 miles of Earth—closer to us than it has been for a century. Is Mars inhabited? If so, are her people trying to signal us even now? Are those annoying inter- ferences that break in on your radio really interplanetary mes- sages? And if so, will men ever be able to decode them? Commander Green, who was one of America’s code experts during the war, tells here the reasons why he believes we even- tually shall be able to communi- cate with the Martians, if such messages are sent. He points out that with the recent advance in radio our chances of “‘getting’’ Mars are 10,000 times better now than 15 years ago, when the planet last passed close to Earth. canals, or dark lines running southward, darken progressively at this time sup- ports the belief that these lines are vegeta- tion bordering artificial or natural canals. | there is still much to learn: Why are there no lakes, rivers, or seas on Mars? Why are her snows yellow? What is the effect of her having seasons twice as long as ours? Why are her surface fea- tures nearly all straight lines? Why do these lines double from time to time? What are those queer shadows that some- times steal across her face? ‘These are some of the questions astronomers hope to throw new light upon this summer. If Mars is inhabited, her people may answer some of these questions for us before long. ‘They may be signaling us even now. Since on August 22, Mars will be millions of miles closer to us than she is ordinarily, and, in view of the tremendous progress lately made in radio, our chances for receiving such signals are at least 10,000 times better than they were when she passed us in 1909. HE theory of the existence of a Mar- tian race is not unreasonable. Biolo- gists and chemists lately have stripped much of the mystery from that phenon.e- non we call “‘life.’”’ Results of their re- search show beyond a doubt that only a few requisites are necessary to life.» They are: warmth, light, water, carbon com- pounds, and some inorganic salts. Every one of these we know exists on Mars. Camille Flammarion, the great French astronomer, quite vigorously asserts that there are people on Mars and that ulti- mately we shall communicate with them as readily as we now communicate with remote portions of our earth’s surface. He concedes that conditions there are in- hospitable. But, he adds humorously, two fish conversing never would admit that any one could live on the banks of their stream, for “‘life out of water would be impossible!” As bearing on the per- sistence of life, it is interesting to recall that British antarctic expeditions have found small creatures frozen solid in the glacial ice of the south polar ice-cap. Few of the creatures failed to revive when thawed out. If a race of reasoning beings does exist

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28 on Mars, its characteristics are not likely to be similar to our own. The reason for believing this is that Mars probably was habitable while the earth was still a ball of fire. Mars is very much smaller and much farther away from the sun than we are. Therefore she must have cooled off ages before the earth did. genie life may have started there millions of years before it started here. And daily, the Martians, if such there be, have seen sparkling in the sky their neighbor planet, our Earth. It is not far-fetched to en- dow such a race with curios- ity. They, too, must yearn to know what lies across the pit of space. Yet they would not try.to come here even if they could fly. They would realize that our atmosphere is so much more full of mois- ture that a Martian doubtless would drown in it. No, the Martian’s efforts would be concentrated on communication. Each time his world swept close aboard us, he would discharge every known form of ether wave in our direction in eager hope we might respond. Imagine that some night in August or September, while you are comfortably enjoying an evening concert with your home set, suddenly and rudely there breaks in upon the soft aria a clear and bell-like note. Angrily, under your breath, you curse all amateur experimenters. The note breaks off. A little later it comes again, this time in groups of dots and dashes. And again, out of patience, you give up, switch off, and sit down to write a red-hot protest to your favorite radio editor. Morning finds you still a-grumble. You unroll the ‘daily paper. Your jaw drops. “SIGNALS FROM MARS!” scream the headlines. ‘‘Experis unable to trace strange radio interference. Little doubt that Martian inhabitants are trying to communicate with Earth!’ And later it proves to be true. What then? Most, people think we should call upon our code and cipher experts at once to read the strange messages. Unfortunately such aid would amount to little. De- ciphering Martian signals would be a problem absolutely different from that of deciphering code messages. For while the inhabitant of Mars may be a two-legged, reasoning creature like ourselves, his mental experience and his mode of con- versing among his own kind may be totally different from anything we ever have known. We have no right to assume any more about Martian signals than that the Martians have ideas, just as we have; and that these ideas are traded back and forth by some system of symbols. Man's early experience in written and spoken language is illuminating. The Neanderthal man drew a picture of a saber-tooth tiger on the wall of his cave to signify that he had a successful hunt. POPULAR SCIENCE MONTHLY Between that rough, primeval sketch and our modern euphonious printed record of Roosevelt’s African exploits yawns a vast chasm of unwritten human history. The Cro-Magnon man, meeting a stranger, held up his right hand empty of weapons to signify the friendly spirit of his heart. Between that ancient gesture and our stiff modern military salute, which has descended from it, spread un- counted ages of changing human customs and mental habits. These examples from our own known story of earthborn life suggest vividly the eMARS (2 This chart shows the relative positicns of Mars, Earth, and other planets with regard to the Sun on August 22, when Mars comes within 36,000,000 miles of us—closer than it has come for a century incredible difficulty of guessing with any accuracy what sort of language a Martian people hundreds of thousands of years older than we and living for ages in a totally different environment might have. HUS, no matter how passionately we may long to plunge into sociable con- versation with Mars when once her signals reach us, or ours reach her, the develop- ment of an intelligible code will be a slow, heartbreaking task. Starting, as we shall have to, with the simple symbol-idea notion, we shall find ourselves at once in the realm of the cryptographer, the scholar whose business it is to translate ancient inscriptions. In many ways his problems are very similar to those we shall face in read'ng Martian messages. Early ideographie or picture writing was worked out on the principle of the caveman’s drawings. Subsequently ab- stract ideas were introduced by sugges- tion. Thus abstract death once was put into writing by a symbol consisting of a human head in a horizontal position with closed eyes. Likewise abstract life was denoted by the same head placed verti- cally with its eyes open. In the course of time the lines necessary to delineate the skull and features were greatly simplified. Eventually the symbol did not look like a head at all. That is the way some letters of our alphabet originated. Earth-Mars communication must be studied from the point of view of two intelligent and reasoning cavemen why have met in the primeval forest and ar determined to exchange ideas. What would two such strangers talk about? The only things they could talk about. or, putting it more accurately, make signs about, would be experiences common ty both, such as food, drink, fire, fear, and mirth. And if the two men were very in. telligent and very much determined to converse, we may picture them exchang. ing real thoughts in the space of an aston- ishing short time. (The writer has gone through ex. actly this experience with the Eskimos of a north Greenland tribe.) Now what experiences are common to an Earth man and a Martian? There are many of them, Night and day, for instance: winter and summer; hea and cold; eclipses; su, stars, comets, meteors, moons (Mars has two), and so on. Once these features have be come mutually identified by sending radio or some other sort of signals to correspond with each, we may then ai- vance to abstract ideographi: signals. For example, ow signal standing for comd might ultimately come to mean swift movement, just a in English the word star has come to mean _ abstractly someone who shines out in the firmament of human endearor. That there would accrue ti us immense profit from com: munication with Mars never has been disputed. Ow MOONS) scientific knowledge might j be advanced thereby thousands of years Martian telescopes must have _ enable them to study our meteorology for many centuries. Hence, with their aid, weather prediction here no doubt would becom § with us an exact science. The fact that a light ray or radio signd § could be reflected back from the surfae § of Mars in less than seven minutes from § the instant of its earthly emission, woull | make it possible to study such phenomena § in a way impossible on earth alone. If we could learn first-hand how the | Martian surmounts his unhappy handicap § of almost universal aridity, we might r J claim our great Western deserts cheaply § and quickly. 7 CONCLUSION, we repeat thati Mars is inhabited and her people a actually trying to signal us, our chan@ of ‘getting’ her this summer are 10, times what they were in 1909. Think what radio progress we hat made! In 1910 Marconi opened his tram atlantic service. In 1913 we mastered wireless communication with speeding trains. In 1915 we connected Washingt with Paris and Honolulu by telephort. By 1921 public broadcasting stations wert opened. Now the world is girdled wi! invisible sound! What a thrilling event that first sign from Earth to Mars would be! momentous episode in history! The mos

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ust be of two nN who nd are What ut? about, € signs mon to ar, and rery in- ned to chang. | aston- (The igh ex- vith the 2enland Ces are 1an and t them, stance; F heat f sun, » Moons 1 so on. ave be ified by e other respond hen ad- ographic le, our come ome to , just as star has ystractly ut in the ndearor. ecrue to An odd radio audi- ence. A loudspeaker entertains hundreds of ducks and geese at dinner-time on a large poultry farm at East Moriches, L. I. The owners say the fowls are fascinated by the music and voices from the big horn ym. com rs neve Ou » might of years enabled or many weather become lio signal > surface tes from n, would j enomena § e. how the § handicap | night re } - cheaply t thati eople at - chane® re 10,0 we hart his trans mastered speeding ashingto2 elephone. ions were dled wit! . } rst signé The mos Saint-Gaudens’ famous bronze Statue of Diana that surmounts the tower of Madison Square Garden in New York City soon may become the world’s most unusual radio antenna. Radio engineers are now considering the feasibility of using this famous statue as an aerial a loudspeaker. in Radio Radio still is a fascinating novelty, constantly finding odd uses in unusual places. Mean- while it has established itself firmly as an almost indispensa- ble part of American home life. Below is a scene in the Washington home of America’s foremost mining engineer, John Hays Hammond, who with his family enjoys the evening radio programs of music, en- tertainment, and news reports An unusual “organ grinder’”’ has made his ap- pearance on the streets of Berlin, Germany. Instead of turning out music with a crank, he turns the dials of a sensitive receiving set that brings in broadcast concerts by means of a loop aerial, entertaining street crowds through The entire receiving appa- ratus is mounted on a specially constructed pushcart, as shown in the picture below POPULAR SCIENCE MONTHLY 29 Every Day Brings Something Novel OOO The time-honored household cookbook is giving place to radio recipes these days. The picture above shows Miss Lucille White in her kitchen at Chicago, Iil., taking down a radio recipe as it is broadcast from a New York station To break the monotony of weary hours of vigil, this canny night watchman in London, England, tunes in his radio set and listens to the latest in operas, concerts, and lectures. With his set he claims to have heard messages from Pittsburgh, Pa., relayed by British broadcasting stations

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POPULAR SCIENCE MONTHLY The Swiftest Traveler on Earth A Dramatic Story of Applied Science at Three Miles a Minute LITTLE more than 30 years ago A one of the many blue-eyed lads in the ancient Norse town of Trond- hjem, about halfway up Norway’s long Atlantic coastline, yearned boy- ishly for a luxury that few men hoped to enjoy at the time. The lad dreamed of owning a bicycle. His parents laughed at him, said such a thing was far too expen- sive, and that Trondhjem and the surrounding country were much too hilly for such a costly contrivance to be of any use. There were a few other bicycles in town, however, and the lad’s determination would not let him rest until his craving for a bicycle was fulfilled. So he collected and sold all his worldly knickknacks, did odd jobs for spare change, and finally astonished his family by lugging homeward triumphantly the bulk of a bicycle sadly in need of repair. “All it needs is a little fixing up,”’ he announced happily; but when that fixing up was nearly completed, he found to his dis- may that all the ball bearings were missing. Not to be outdone, he carved a set of ball bearings by hand out of weathered oak knots, soaked them in oil to harden them, and soon he was the proud possessor of a bicycle that not only ran, but ran so well that he challenged and beat nearly every one else in town. HE name of this determined lad was “Sig’’ Haugdahl, known about Trondhjem as “Sig the Racer.” Today the same blue-eyed lad, grown to manhood and an American citizen, is the speed king of the world, the creator and possessor of the fastest car in ex- istence, the ‘“Three-Miles-a-Minute Wis- consin Special’? with which he has at- tained the phenomenal speed of 180.27 miles an hour, or By Fritz Blocki OI a “Sig” Haugdahl, cigar, he says, serves as a “‘cushion for his world speed king. The teeth” as his racing car thunders along Shortly after the bicycle episode, Haugdahl’s fancy sped across the sea to America, where he knew he had an uncle somewhere in Minnesota. To his parents’ dismay he announced he was going to set out to find his uncle and with only enough change in his pocket to reach halfway to his destination. Nevertheless he boarded a train and finally made his way to Minneapolis, “broke” but happy. After a day and aq half of ceaselessly tramping the streets, _ he located his uncle, who put him to work in his butcher shop. But tying up pork chops and weighing out hams was not to Sig’s liking. He wanted something mechan- ical, something speedy. So his uncle sent him to work in a carbide-lamp factory in the town of Albert Lea, Minn. Sig went with joy in his heart and stuck at his new task until he had mas- tered the small factory and all its machinery. _ at Albert Lea, Haugdahl became acquainted with a new type of bicycle—the motor- cycle. It was not long be fore he saved enough to buy what was little more than a wreck of what once had been a_ two-wheeled machine. The gasoline engine was new to him, so he set out to master its intricacies by practically re building the machine with the avowed purpose of making a racer out of it. At the first opportunity he entered his rebuilt creation against professional racers and made a creditable showing. Thus began his career as a speed king. AUGDAHL § stuck to motorcycle racing until he had established the mark of 103 miles an hour—a record at | the time—and had further demonstrated his extraordinary staying powers by riding out one race with a broken leg resulting from a spill on the back stretch. After recovering from this accident Haugdahl decided four wheels would be safer than two when more than three miles a minute. This is the fastest that any man ever has traveled over land or water, faster than the speed of most airplanes. Haugdahl holds all the world’s speed records from one to 10 miles, and- has more dirt-track rec- ords to his credit than any race driver flirting with death at high speed. So he entered the auto- racing game, first as mechanic, later 4 driver. Meanwhile the world speed marks advanced from a mile a mil- ute, which for 4 long time was Ccor- sidered an end!l- mous speed, to 1 miles an hour, which was thought to be today. In the last season he estab- lished more than 20 new dirt-track marks, two of which were world records. The story of his rise to supremacy among the “knights of the roaring road”’ is as spectacular as was the winning of his first lesson in mechanics back in his seaport home. Haugdahl making three miles a minute in his record-breaking car at Daytona Beach, Fla. greater opportunities. Knowing young Sig was not to be gainsaid, they bade him Godspeed, bought his passage and gave him the equivalent of about $10. Soon afterward he landed in New York, able to speak only a few English words that he had picked up from the boat crew, and unbeatable. It remained for Tommy Milton, famous speedway ace, t0 shatter the mark in a Duesenberg car at 4 speed of 156 miles an hour. The rac course was the natural sand speedway at Daytona Beach, Fla. By this time Haugdahl was a veteran of the racing game. He knew cars, theif defec drear three attail sure H' paid The It we ful, ¥ in th Ha powe space less resist ancir see \ founc accid Gulf, by | pare! The lem ¢ He s and car v Th suita powe attai enor! a ve used over final mot ment it mi to A hims i i night recor befor Space to be resist

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h set to 1 and polis, and a reets, work chops 1S Was He >chan- y. So ) work actory t Lea, th joy at his 1 mas- ry and t Lea, yecame . new motor- ng be igh to > more it once vheeled -asoline out to ally re- sorcycle hed the cord at | istrated ers by ken leg stretch. accident ould be vo when death 1d. So he auto- , first as ater as anwhile speed dvanced . @ mil for 4 yas cole | enor- , to 10 ir, which t to be ned for y ace, to car ata [he race peedway _ veteran ars, theif defects and their possibilities, and he dreamed of attaining a speed of more than three miles a minute. When Milton attained 156 miles an hour, Haugdahl was sure he could realize his great ambition. E STUDIED the layout of Milton’s car. It had the necessary power, but paid for this power in increased weight. — The bulk increased the wind resistance. It was well balanced, enormously power- ful, wonderfully built, and the fastest car in the world at the time. Haugdahl’s problem was to attain the power of Milton’s car while lessening the space occupied by the motor, and achieving less weight, less body width, less wind resistance, and perfect bal- ancing. He went to Florida to see Milton’s car, and there he found the solution quite by accident. While boating in the Gulf, he saw a huge fish glide by like a flash, with no ap- parent resistance to the water. The fish had solved the prob- lem of resistance. Why not he? He started north immediately, and designed the body of his car with the fish as his model. The next thing to find was a Rear view of the world’s fastest car. The bullet-like “fin” behind the windshield prevents suction suitable motor, one of at least 200 horse- power, light in weight, flexible, capable of attaining enormous speed and standing enormous strain, one that would fit under a4 very narrow hood and that could be used with a narrow radiator, without Overheating. After a long search he finally found a Wisconsin hydroplane motor, originally turned out for govern- ment use in a flying boat. It looked as if it might do, so he bought it and shipped it to Albert Lea, Minn. There he secreted himself for 11 months in his workshop. THE difficulties that Haugdahl sur- _. Mounted in those 11 months of night-and-day toil never will be fully recorded. Many changes were required before the engine would fit into the small Space Haugdahl determined would have to be sufficient if he were to nullify wind resistance. The hanging of the engine shield. POPULAR SCIENCE MONTHLY Front view of Haugdahl’s “Three-Miles-a-Minute Wisconsin Special,” showing the extremely narrow, streamlined and low-slung body, with rounded nose and tiny, slanting wind- A fish seen in Florida waters served as his model had to be changed. The suspension of the body had to be determined to the smallest fraction of an inch. The oiling system had to be made more compact, yet with increased capacity. The water cir- culation system had to be adapted to a smaller radiator than was originally in- tended for a motor of that size. Rods, axles, every exposed part had to be beveled and set to cut the wind. (y= by one Haugdahl solved these difficulties, most of them before the car ever turned a wheel. The body he hammered of sheet steel by hand. He made it only 20 inches wide at its widest part, at the driver’s seat, just behind the low-hung engine, and 16 feet long. His oil-reserve tank he placed back in the body of the car instead of above the engine, and the oiling system pressure he increased to the maximum. He also made all the water connections oversize to allow the freest possible circu- lation. The radiator, especially designed, was only 18 inches wide, with a fishlike fluted nose, offering a minimum of wind surface. The body itself was a continuous stream- line affair, built like the fish he had seen in Florida, with a thin, bulgeless body, tapering into a knifelike tail that was fully inclosed at the bottom to prevent air suction at high speed. At the top, where Haugdahl’s head would have to be when driving, he erected a small slanting windshield, about six inches wide, nine inches long and four inches high, of thick plate glass. To close the vacuum that might be caused behind this little raise of glass, he added a bullet-like miniature tail just back of his seat. 31 After beveling the reach-rod connecting the steering knuckles on the front axle and other exposed parts, then covering them with tape and covering all outside joints with leather jackets, he quietly shipped the fishlike creation to Daytona Beach. After a day or two of adjusting, Haugdahl told the judges he was ready, got his curious machine going, and flashed by at a speed of 161 miles an hour. He had achieved one of his ambitions—to be speed king of the world! But he had not yet made three miles a minute. So he told the judges to give him another chance. On April 19, 1922, after a few minor changes, he again flashed over the electrically timed natural speedway at Daytona Beach at the amazing speed of 180.27 miles an hour, or more than three miles a minute, covering a mile of ground in 19.97 seconds —faster than any other man ever had traveled on land. OT content with that, he established further records in all distances up to 10 miles. Thus, starting with little more than a hobby for mechanics, perseverance, and an inordinate craze for speed, he had ac- complished, practically single handed, what others with un- limited resources had been un- able to achieve. Yet he was not satisfied. With the world records for the straightaway in his possession, he set out to chalk up a new set of dirt-track records. This he has succeeded in doing with his car exactly the same as it was on the Florida beach except for a slight change in the gear ratio for mile and half-mile tracks. The power plant that made these achievements possible is a six-cylinder hydroplane engine built mostly of alu- minum and weighing only 600 pounds. It has a piston displacement of 756 cubic inches and in spite of this great displace- ment turns more than 2000 revolutions a minute. The motor is geared at a ratio of 1?/, to one directly to the rear axle, doing away with clutch and_ transmission. Thus the engine can be run only when the car is on a race track. The compression is so great that it cannot be cranked. Four men are necessary to start the car by pushing it. With the engine throttled down, the car “‘idles’’ along at 35 miles an hour. 6 ee engine hangs so low that the ground clearance is only three inches. The driver’s seat and the opening in the body above it is so small that only the diminutive Haugdahl, who stands five feet four inches in height, can get into it. The weight of the entire car is less than 2000 pounds. The driving strain at the terrific speed the car develops is so great that Haugdahl carries a cigar in his mouth as a “‘cushion for his teeth.”” One time he forgot that his cigar was lighted. When speeding at “only” about 120 miles an hour, he turned his head slightly. The wind blew the cigar into a flame and burned it to his face in an instant nearly causing him to wreck the car.

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POPULAR SCIENCE MONTHLY Professor Gault at work on the riddle of telepathy, or thought transmission, in his study at Northwestern University elepathy Put to the Test | By number of cool-headed ob- servers believe implicitly in Robert H. Gault, Ph.D. OST of us have heard stories of the father 4 and mother who have lived together for 40 years and who, one evening as they sit under the reading-lamp, engage in the following conversation: ; ‘‘Wonder if John won’t come home this Christmas and bring Mary with him,’’ remarks the father. S THERE really anything in telepathy, or mind reading? Is there any scientific basis for believing, as many of us do, that one man can communicate his thoughts to another merely by wishing to do so? The unusual experiences that have come to most of us—the utterance of a thought at the precise moment that the same thought is put into words by another; the unexpected telephone call from an almost forgotten friend momentarily in, our thoughts—can these be traced to transference of thought, or are they, as many insist, only coin- cidences? Not long ago a group of scientists headed by Profes- sor Robert H. Gault, eminent psychologist of North- western University, and Professor Gardner Murphy of Columbia University, conducted by radio what probabiy was the most extensive experiment in tele- the claims they set forth. I have in mind a telepathist of the sort who has demon- strated far and wide. I shall describe two of his perform- ances and add my interpreta- tion. FIRST met him in con- pany with several other men in a downtown club. When my opportunity came to put him to test, I selected a series of ‘‘mental’’ commands that | “Why, I was just thinking the very same thing!’’ comes the response from over the knitting needles. Such an incident often passes as evidence of thought trans- ference by the mere energy of pathy ever made. other novel The results of the test and of experiments are presented here by Professor Gault in an absorbing article that sheds new light on what has been—both to the scientist and the layman—a profound puzzle for centuries. would give him. They were known only to myself. ‘‘Go to the desk”; ‘Take a match from the box’; ‘Carry the match across the room to the little table upon which are a thought, or telepathy. But is it necessary to interpret the case in such a way? Remember that the father and mother have passed many winters and many evenings together in the living-room by the reading-lamp; that during all these years the evening has been the time for thinking of absent members of the “family and the time of leisure for speak- ing of them. Furthermore, it is near Christmas—the time for thinking of young folks coming home. Considering all these circumstances it does not require a great stretch of imagination to interpret the simultaneous expression of the same thought as a coincidence; a coincidence, to be sure, that has been conditioned by the habits, mental set or disposition of a lifetime. The fact that in ninety-nine of a hun- dred cases stories of this kind are accepted as evidence of thought transference indi- cates a certain slovenliness in method of observation. For example, who ever took the precaution to assure himself that it was exactly at a particular moment that he thought of John and Mary? The good mother at her knitting may have thought of the possible Christmas homecoming some minutes before her spouse spoke up, but at the moment of utterance the thought seems to have been simultaneous, - and so it is uncritically described as a case of telepathy. trick of memory. Such is the illusory MUCH more striking illustration of what passes for telepathic communi- cation is discovered in the professional who finds objects that another has hid- den and who obeys ‘“‘mental”” commands. Many such persons perform really aston- ishing feats. They believe in all honesty that they are genuine telepathists, and any water pitcher and two inverted tumblers”; ‘‘Turn up one of the tumblers”; ‘Place the match inside it’; “Shake it about”; ‘‘Remove the match from the tumbler’; ‘‘Leave the tumbler in its place and carry the match over to the telephone stand in the corner of the room”; “Place the match upon the stand beneath the tele phone instrument.” _.. These commands I. “thought” one after another, never passing on to @ new one until the preceding one had been obeyed. The telepathist walked from place t place in the room and I followed at 3 distance of two or three feet behind him. During the entire test he exhibited 4 set, intent facial expression except for a somewhat sleepy look about his eye: No questions were asked and not a word passed between us until the test wa completed. I alone of all the men in the (Continued on page 11+)

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{ 1 ob tly in h. yathist lemon- I shall rform- ‘preta- com- other When to put . series that | y were “Go to match ry the to the . are a rverted one of 1 inside ve the ave the ry the and in ace the he tele t’’? one n to 2 ad been place to ed at a nd him. ibited @ cept for nis eyes. ae: word est was on in the of stopping automobiles, bringing down flying airplanes, killing men and other destruction have come from many parts of the world in the last few months. A dozen or more inventors have an- nounced the discovery. of means for transmitting electrical energy in any direction - without Gt ston of mysterious rays capable POPULAR SCIENCE ‘MONTALY said, in exploding charges of powder by a beam at a distance of several feet. But more than any other, the claims of the British inventor, Mr. H. Grindell- Matthews, have attracted wide attention. His remarkable experiments have_ been witnessed by scientists, journalists, and government officials. There seems little 33 “Man’s Most Terrible Invention” By Frederic Mortimer Delano mobiles or airplanes, even without pro- jecting any destructive force toward them. He asserts that the special ray or beam he uses for the purpose of power projection serves, even when uncharged with power, as an efficient paralyzer of the ignition systems of gasoline engines. At the request of the editor of POPULAR SCIENCE MONTHLY the use of: inter- mediate trans- mission wires. While admitting the scientific possi- bility, most experts have been frankly skeptical and others have openly ridiculed the claims of the inventors. But the idea of a malignant elec- trical charge with the speed of light- ning, which can kill men and shrivel up airplanes in flight, and inter- fere with the work- ing of gasoline engines, has caught popular imagina- tion. There is to such a thought something of the thrill that H. G. Wells, some 30 years ago, im- parted to his book, “The War of the Worlds,’”’ when he described the descent of weird beings from Mars armed with mysterious engines to direct beams to destroy the earth and shrivel its people to death. H. Grindell-Matthews, British inventor, is shown above in his laboratory demonstrating the “‘mystery ray’? apparatus with which he claims he can transmit power without wires or other conductors, and stop the operation of -I went to London to interview Mr. Grindell-Mat- thews. Let me de- scribe the four ex- periments I saw him carry out in his laboratory. T ONE end of the laboratory is an ordinary motorcycle engine attached toa single wheel, like the rear wheel of the motorcycle. En- gine and wheel are mounted so that the wheel can re- volve and the en- gine can operate just as in a moving motorcycle on the doubt that he actually has succeeded in transmitting a substantial quantity of power over distances of a few feet without wires or other conductors. Further, he claims to be able to stop the operation of ordinary internal com- ordinary internal combustion engines. At the right is a motorcycle engine, geared to a single revolving wheel. In his experiments, Grindell- Matthews stops this engine simply by turning his invisible ray on the magneto system road. At the other end of the room is the generator for the new ray. Mr. Grindell-Matthews adjusted the generator and started the engine. At a given signal he turned his in- visible ray on the magneto system of the barking engine. Instantly the explosions stopped and the engine began to slow ND as a _ curious public speculated, the numbers of inventors claiming such rays swelled. Widespread doubt and the mystery with which the in- ventors have surrounded their discoveries seemingly have served to augment, rather than allay, public interest. Herr Wulle, ‘chief of the militarists’’ in the German . Reichstag, informed that body that his government had a de- vice that would bring down air- planes, stop gasoline engines and “spread a curtain of death.” Trotzky investigated the po- tency of a ray. invented by Grammachikoff, and the British Air Ministry has aided a similar invention being developed by Prof. T. F. Wall of Sheffield University. ; A Parisian engineer offered to demonstrate his ability to stop the engines of automobiles run- ning on the open street. A similar claim was put forth by a German at the radio station at Nauen, while a second French inventor has succeeded, it is bustion engines, such as those of auto- Dramatic Possibilities that Lie in the ‘‘Mystery Ray”’ X 7ITH something akin to horror, men and women have discussed recent reports of inventions of ‘‘diabolic rays’? powerful enough to leap out and slaughter thousands of human beings. When the astonishing claims of Mr. Grindell- Matthews, British inventor, were announced, POPULAR SCIENCE MONTHLY sent Mr. Frederic Mor- timer Delano, an able and capable investigator, to London to interview Mr. Grindell-Matthews. Mr. Delano’s report on the invention that aroused three nations begins on this page. It is an exclusive, fascinating, first-hand description of the remarkable experiments he witnessed. POPULAR SCIENCE MONTHLY, in common with many leading scientists of the world, is unwilling at present to affirm all of the claims made for the several ‘‘mystery rays.’’ However, it is generally admitted among scientists that such a ray is at least a scientific possibility. Whether Mr. Grindell-Matthews and the other workers in the field have, or have not, overcome the many practical obstacles in their way, cer- tainly they have suggested a possible method of transmitting power without wires. In a vivid, understandable way Mr. Delano points out the possibilities of such a suggestion. down. Mr. Grindell-Matthews turned off his ray; the engine started up again. This was repeated; the signal being given each time by one of the observers, preclud- ing any possibility of pre- arrangement of times of starting and stopping the engine. Ample opportunity was given those present to examine the engine for concealed connections or other attempts at fraud. ‘TH second experiment was the explosion of gunpowder by the ray. A little powder was placed in a dish at one end of the room. When the ray was turned on it from the other end of the room, the powder instantly ignited. In the third experiment an ordinary electric-lamp bulb was attached to two wires and these wires were held by two persons, thus suspending the lamp in the air and at the same time keeping the persons who held it at a safe distance from the path of the ray. When the ray was turned on, the lamp glowed as bril- liantly as though the current

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34 were passing through it in the ordinary manner. The final experiment was designed to show the death-dealing properties of the ray toward living creatures. A live mouse was placed in a cage at one end of the room. The ray, now made visible to facilitate a direct hit and appearing as a thin pencil of lavender-colored light, was trained for an instant on the mouse. Instantly the little creature stiffened and died, with all the symptoms of violent electric shock. HESE are the actual experiments performed by Mr. Grindell-Matthews; not once but many

POPULAR SCIENCE MONTHLY that the beam strikes, say the powder, and flows thence to the ground. The complete circuit, providing for the return of this current to the generator, is made by the earth, as in the old-fashioned one- wire telegraph systems. In actual use the carrier beam is generated first, in an apparatus the con- struction of which Mr. Grindell-Matthews refuses to describe. From this apparatus the carrier beam escapes through a lens, much as does the beam of a searchlight or a magic lantern. After the carrier beam has left this lens, the power-carrying electric current is superposed on it. Indeed, Mr. Grindell-Matthews states, as in the use of tracer bullets for a rifle or a machine gun. Though Mr. Grindell-Matthews has refused, as yet, to disclose the exact nature of the carrier beam that is the essence of his invention, it is possible to make some guesses about its nature, and European scientists have not failed to make these guesses. The prevalent opinion is that the beam is related in some way to ultra-violet light. When ques- tioned, Mr. Grindell-Matthews denies that his beam is ultra-violet light, but the fact remains that ultra-violet light would do about what Mr. Grindell-Matthews says that his carrier beam does do. It would make the air in the path of a beam

times. Disinterested . and competent wit- | nesses have observed all of them. Mr. Grindell-Mat- thews does not dis- close the exact way in which this remarkable ray is produced. He does say, however, that the secret lies in what he ealls_ the “carrier beam”’ along which the power is projected. Previous investigators have at- tempted to project actual beams of heat waves or beams of electric waves similar to the waves used in radio. Mr. Grindell- Matthews does not claim to do this. His device, he says, is a beam of special vibra- tions of secret nature, a beam that does not constitute the power, but merely provides a path along which the power can be sent. It is as though you reached out with a wire and touched the vic- tim. The special carrier beam is a conductor of electricity, just as a wire is. Along this beam passes a high-voltage, low-frequency elec- tric current. It is this current, Mr. Grindell-Matthews says, that killed the mouse, set fire to the powder, and lighted the lamp.

HE power-carrying beam can be directed also against an engine magneto, but its effect, it is claimed, will be destructive, not paralyzing. The electric power in the beam will burn up the wind- ings. For a mere paralyzing effect the carrier beam is_ projected alone, without power in it. Since this beam is a conductor of electricity, when- ever it impinges against the windings of the magneto, it makes conductors of the spaces around these windings. The coils are temporarily short-circuited. The magneto ceases to operate. For actual destruction—that is, when the carrier beam is charged with power— it is necessary to provide a ground con- nection for the object to be destroyed, as, for example, the exploding powder. The conducting carrier beam is only one side of the circuit. The electric current that flows out along the beam enters the object

How the perfection of a power ray eventually might be used to halt a distant motor- car by killing its engine, and to deal electric death to the occupants of the car A SHORT CIRCUIT SETWEEN PRIMARY ANO pre SECONDARY * Cot . Py Ss =< ae

te jt» by gd ay.) ivi ¥ 4 YNS 4; %

This diagram shows the method by which a special carrier ray, even when uncharged with power, paralyzes the ignition system of a gasoline engine. The ray causes the space around the magneto windings to become conductive of electricity, and the current leaks between the primary and secondary windings, causing a short circuit. ceases at the spark plugs and the engine immediately dies the conductivity of the beam for the low- frequency electric current is greater if the beam also carries at the same time a high- frequency current. Accordingly, two separate electric currents are added to the beam, each by a special generator. One of these is high frequency; the other is low frequency. The latter carries the power. The carrier beam itself may be made either invisible or visible, as desired. The visible ray is useful at times when one wishes to trace the path of the ray or to know just where it is impinging against a distant object. The principle is the same As a result, sparking more or less a con- ductor for electricity. LTRA-VIOLET _light does this by what is called ‘fonization” of the atoms of gases in the air. This ultra-violet light, you remember, is merely a variety of light the waves of which are extremely short, much shorter than the waves of ordinary light. It is invisible to the hu- man eye, but it does affect the photo- graphic plate, and it has many other chemi- cal and physical ef- fects well known to the scientists. Air consists, in the main, of a great num- ber of atoms of two gases — oxygen and nitrogen. These atoms, like all other atoms, are composed of a number of electrons revolving around an atomic nucleus, much as the earth and the other planets revolve around the sun. In the i atom of nitrogen there are seven of these planetary electrons; in the oxygen atom there are eight. N ORDINARY air these atoms -are- quite stable and do not carry any unneutralized charges of electricity. Accordingly, air is not a conductor of electricity. but whenever a beam of ultra- violet light strikes against an atom of oxygen or of nitrogen, one of the planetary electrons may be driven entirely out of the atom. The nitrogen atoms of the air lose one of their electrons and become what are called nitrogen ions. Each one has only six electron planets instead of the seven it had before. In the same way the oxygen atoms lose one electron and become oxygen ions, each with seven planetary electrons instead of eight. That is ionization. One of the most important results of ionization is that the air becomes a con- ductor for electricity. Each ion has a small charge of positive electricity. These charges act as carriers for the current. Air with many ions in it may have its (Continued on page 117)

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Oe moO Dern aT all ng ch ts he en At. ns ne en ’ b t H a i : H See ARS 2S path ETN POPULAR SCIENCE MONTHLY 35 Why You Make Errors in Summer By Donald A. Laird, Ph.D. Associate Professor of Psychology, Colgate University effect the weather exerts on your daily life and activities? How much less work do you think you ean do on the hot days that are more or less seasonable now than you could on pleasant days last spring? To what extent do you think your ability to concentrate has been affected by the heat? How much less accurate do you | WONDER if you realize how much able to assume that varying n.eteorologi- cal conditions affect directly the chemical processes of the body. At this time of year, for example, the chemical action of our bodies is increased _ to such an extent that waste products pile up more rapidly than we can absorb oxy- gen to destroy them. The effect of this accumulation of waste is the same as proved theory. Whatever causes our supply of energy to hop up and down like the mercury in a thermometer, the fact remains that it does so, as shown by a very comprehensive test conducted by Doctor Dexter. This test was entirely practical and the subjects did not realize that it was being made. They were the clerical forces of several banks in a large think you are now than you were a few months ago? Very little, you prob- ably will say. But science knows better. Scientific tests of workers in di- verse lines of endeavor show that on the hot and sultry days of summer your energy, and conse- quently your physical and mental efficiency, may be reduced by as much as 60 per cent! Moreover, when the thermometer registers 90 degrees or more, you are about twice as likely to make an error in work requiring concentration and accuracy as you are on days of moderate tem- perature! HESE figures, of course, are extreme. But science has learned that variations in the weather cause surprising variations in human energy. Large business con- cerns have recognized that their employees are affected by weather changes. When Dr. Ed- win Grant Dexter, psy- chologist, who now is director of the National Institute of Panama, was investigating the effect of weather and climate on human efficiency some time ago, he was told by the head of a factory em- ploying 3000 workers, that a disagreeable day yields about 10 per cent less work than a fine day. I, myself, have re- ceived similar testimony from employers, and have noted the fact in the classroom. Now, just why our ability to work and concentrate varies with the weather Science has not determined exactly. The decrease in efficiency that comes with dis- agreeable weather probably is due in part to discomfort. Another tenable explana- tion, however, is that the lowered effi- ciency is due to changes in the metabo- lism, or chemical action of the body. It is a law of chemistry that chemical activity is speeded up by heat and re- tarded by cold. And so it is quite reason- Delicate electrical apparatus used by the United States Bureau of Mines in scien- tific tests to determine the effects of high temperatures on the health, comfort, and efficiency of the human body. Sur- face temperatures of a human subject under intense heat in an adjacent test chamber are recorded by means of the potentiometer, shown above, which is mental confusion. fatigue; hence, the inertia that prevails in the summertime; the reason why summer- time is mistake-time. However, we can- not blame it all on the summer. Intense cold also causes a reduction in physical and mental energy. In this case, the chemical processes of the body probably are so slowed up by lack of heat that the energy produced falls below normal. All of this means that it behooves you to make especial efforts to guard against errors in your work whenever it is espe- cially hot or especially cold. I am not basing this advice on an un- connected by wires with a thermocouple in contact with the subject’s body. Among the effects of high temperature on the body, as shown by the tests, were exhaustion, restlessness, and irritability, headache, palpitation of the heart, in- flammation of the eyes, dizziness, and Weakness “dragged out”’ feeling followed the test eastern city. They merely went about their daily work, and their efficiency was checked up by noting the errors they made. It was found that the number of errors was low in spring, that it increased markedly during’ the summer, dropped again during the fall, increased again during the winter, though not to the sum- mer maximum, and then dropped in the spring. SIGNIFICANT co- incidence regarding this seasonal occurrence of errors was that when the results of the inves- tigation were plotted graphically, the curve of errors resembled remark- ably the curve of the death rate. In other words, weather, health, and efficiency apparently bore definite relations to one another. Dr. Ellsworth Hunt- ington, of Yale Univer- sity, has made an ex- haustive study of the effect of weather and climate on human efficiency, with similar results. Doctor Hunting- ton conducted his inves- tigation among 2500 workers in Connecticut, North and South Carolina, Georgia and Florida, and among all the students of United States Military Academy at West Point and the United States Naval Academy at Annapolis. He found that the mild months—April and October par- ticularly—were most conducive to effi- ciency in both mental and physical effort. For most physical workers, temperatures averaging between 55 and 65 degrees were best; that is, times when the average daytime temperature was about 75 de- grees, dropping to 45 degrees at night. Mental workers seemed to do better at lower temperatures—when the _ ther- mometer reached 55 degrees by day and dropped to freezing at night. Neither class of workers did well either in excessively hot or excessively cold and a

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36 weather. As soon as the average tempera- ture dropped below 30 degrees or rose above 70 degrees, there was a definite falling off in efficiency—as much as 60 per cent when the thermometer reached 90 degrees or more. The effect of temperature on efficiency varied, of course, according to location. Thus, workers in Flor- POPULAR SCIENCE MONTHLY is itself a change after a period passed elsewhere and the benefits of the trip to the country are multiplied correspond- ingly. One class of workers makes its own weather changes through virtually the whole year with most satisfactory results —salesmen and others who pass part of quence should make an admirable time for work. That it does not probably is due in great measure to the fact that most winter work is performed indoors, where artificial heating dries the air. Stout persons generally are supposed to suffer more from hot weather than their slim neighbors. Possibly they do, in point of discomfort; yet the ida, accustomed to rela- tively higher tempera- tures the year through than workers in New England, were able to withstand temperatures above 90 degrees with- out any such loss of efficiency as the North- erners showed for cor- responding tempera- tures. OW, from this you might assume that you can acquire inde- pendence of the weather by seeking a uniformly mild climate and living and working there the year round. Doctor Huntington’s test, however, shows that the weather prob- lem is not so easily solved. Where there is little change in temper- ature from day to day, he found that the qual- ity of work gradually declines. The human body requires change, and a change in the weather, whether for better or worse, in- variably was found beneficial. Even a rainy day after a long spell of fair weather was a mental and physical spur. Similarly, , % 5” 50° 75 The broken line indicates how the number of mistakes in bookkeeping varies with tem- perature. Notice that the point of greatest efficiency lies at about 60° -F., and that the number of mistakes generally increases with the rise in temperature above that point either a rise or fall in temperature in- creased productiveness, except when the change was very great and very sudden. ~ IS on this liking of your body for change that the beneficial effects of a summer vacation depend. Merely resting from your accustomed labors for a couple of weeks in the summer will benefit you, but the best vacation is one that includes a climatic change. The man from inland who visits the seashore and the man from the coast who goes to the mountains both subject their bodies to unaccustomed climatic influences, with the result that their physical processes are stimulated and they return to their homes refreshed and invigorated. Moreover, their return Intcrior view of the insulated test cham- bers where subjects of the Bureau of Mines experiments, stripped to the waist, under- go varying degrees of high temperature and humidity. accurately record their bodily reactions to the heat—their weight, temperature, res- piration, heart pulsations, and blood pres- 90° Precision instruments their time outdoors and part indoors. Usually they are conspicuous for their energy, and it is quite conceivable that this energy has its source in their frequent exposure to widely varying temperatures. A SCIENTIST of my acquaintance utilizes this stimulating effect of fre- quent weather changes. He keeps his laboratory or office at a temperature of 65 degrees or so, but, when doing any sort of intensive work, he goes frequently to an open window to work or think. Thus he reduces the external temperature of his body by a cool draft and consequently im- proves his working efficiency. Besides temperature, humidity—the moisture in the at- sure. The experiments disclosed that the human body, in a state of rest and in still air, cannot endure indefinitely a tempera- ture higher than 90° F., with 100 per cent relative humidity. They showed also that while fat men lost more weight than lean ones when subjected to uncomfortably hot temperatures, they were less exhausted United States Bureau of Mines determined recently that some fat men actually stand the heat better than lean ones. Among a group of men tested for their physical reactions to extremely high temper- atures, the heavier and stouter men lost more weight than the lighter and thinner ones; yet they were able to stand the high temperatures for alonger time and complained less of ex- haustion when the test was finished. T IS difficult to be your own weather maker in the summer- time. In winter you can stay indoors, go out, humidify the air and otherwise modify atmospheric conditions to some extent. In sum- mer, though, outside of turning on the electric fan or taking a cooling shower bath, there is little you can do to reduce your body temperature. Of course, the weather supplies a handy excuse any time we don’t feel like working, but why not be honest with ourselves, and blame the weather only when the weather is at fault’ Guard your attitudes. Don’t let them lower your efficiency. In other words, don’t quit to the weather without a figrt If, on. the*days when you don’t feel like working, you make a special effort to work particularly hard, it is altogether likely that so far as you are concerned summertime will cease to be mistake- time. mosphere—has con- siderable effect on working efficiency. As a general thing, moisture in the air increases our supply of energy, perhaps by helping the chemical action of our bodies, perhaps by making us more comfortable. Exces- sively humid days, which are common e . R ' at this time of year, —— however, lower the ¢|_Giow. working efficiency, Ci VERY Low probably because they are very hot in addition to being very moist. The air in winter ordinarily is moist enough, and winter in conse- This shaded map of the world, reproduced from “Civilization and Climate,”” by Ellsworth Huntington, noted geographer, indicates a definite relation between temperature and human efficiency. Notice that the regions of highest efficiency—the United States and western Europe, indicated by the black and heavily shaded portions—fall mostly in the temperate zone, between 30° and 60° north latitude. The lowest efficiency, on the other hand, is found in the extreme heat of the equatorial regions or the extreme cold of the polar regions . ‘ i : : Me ty ys ete Nt I i AG NNT LOREM EE AICS ule EI AES j & @ ; ‘ ¥. i : = i '

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tS ALONE ASE RIYA ALE MII POPULAR SCIENCE MONTHLY 37 Dewdrops Display the Spider’s Art AVE you seen a spider’s web, glistening with dew in the dawn? Nature offers no more charming sight, for the dewdrops reveal the marvelous structure and beauty of the spinning Sa No two spider webs can be exactly alike, for their shape is determined by the location of the twigs to which the supporting threads are fastened. The web forms an effi- cient telegraph system. The spider learns that its prey is in the toils by vibrations caused by the captive’s struggles The compact, close weave of a web like this makes it easy to understand how the spider sometimes uses its silk for an airplane, floating with the wind at great heights The threads of the web are of silk, 100 times finer than hair, yet stronger than steel, and consequently capable of en- meshing even large insects upon which the spider bandit satisfies its appetite The threads that make up a delicate web like this issue from glands in the spider’s body. The first thread spun is per- mitted to float in the air until it catches on some object. Then the spider creeps along it, fastens the other end, and be- gins construction of the intricate network Dewdrops glistening on a spider’s web at early morning resemble ropes of tiny pearls. The effect is beautiful, but annoying to the spider because the dewy festoons are plainly visible, making the web of very little use as a snare A half-hour suffices for the construction of even so complicated a web as this. The spider usually works at night. The outline is spun first; then the spider fills it in, in- stalling the threads that radiate from the cegter, and last of all spinning the cross threads. These are wound in symmetri- cal pattern, crossing the others at angles of about 90 degrees. The spider makes doublysure of capturing its prey by smearing the completed web with a glue-like, clinging substance Some members of the spider families weave their webs in tangled veils like this. It seems remarkable that the spider never becomes enmeshed in its complicated net. Its in- stinct, though, enables it to find its way about

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POPULAR SCIENCE MONTHLY Straight Up! The Dream of Fliers By W. F. Gerhardt HE helicopter, one of £ ' the earliest forms of i. heavier-than-air ma- : chines, but neglected during the years when the airplane was being developed, recently has come into considerable prominence, and its “renais- sance” has resulted in -com- ment that is of a widely divergent sort. Many of its exponents would have us believe that the future will see it dis- placing all other forms of aircraft, while its opponents are equally insistent that its possibilities are so limited as to be negligible. A favorite statement of those who see little in the helicopter is that it can do nothing that a balloon cannot do. Of course, neither of these views can be entirely correct. It is obviously im- possible to pass on the merits or de- merits of a mechanical apparatus that has not yet reached its final form, and the helicopter today is far from perfec- tion. In fact, the helicopter as we know it must be regarded merely as a step in a development. The machines of the future probably will be quite different from those we have seen. Certainly they will be simpler. Now, just what is a helicopter? What is it supposed to do, and how does it accomplish its purpose? ROBABLY the name itself will shed a little light on the sort of machine it is. Helicopter is derived from two Greek words—helix, a spiral, and pteron, a wing. In other words, a helicopter is an aircraft with spiral wings, or at least wings that describe a spiral path in ascending or descending. This construc- tion permits the machine to rise straight up in the air, instead of rising in a gradual incline like an airplane. In a helicopter the screw effect of a revolving propeller that drives an airplane forward is utilized to produce a vertical lift. The mere ability to go straight up and down, however, will not make the heli- copter a practical, useful aircraft. It must, in addition, do everything an air- plane can do, which means that it must possess mobility, stability, control and the ability to effect a safe landing in case its motor fails. If it is to match an airplane in mobility, the helicopter must be able to climb from the ground to an altitude of several Chief, Flight Research Branch, U.S. Air Service, - McCook Field, Dayton, Ohio LY The Berliner airplane helicopter, showing the two horizontal propel- lers. The first helicopter to make a_ controlled ‘ flight to its starting point doing this for more than a comparatively few feet. Beyond the ability to climb, the helicopter must also have a horizontal speed at least equal to the cross-country speed of an automobile, or it offers no advantage as a means of transportation. But the most difficult and probably the most important problem is that of providing the helicopter with a means of landing safely when the motor fails. A pure helicopter should be able to de- scend vertically and land safely; that is, drop to the earth with controlled speed that would gradually lessen and cause the machine to come to rest softly and slowly. To effect this the screws must be large—comparable in area with the wings of an airplane. “THERE are hybrid machines—airplane helicopters—that, when the motor fails, glide to earth like airplanes on aux- iliary wings. Like airplanes, these machines have high ground speed in landing. Hence, they either must be traveling at that speed when the motor fails, or, if stationary, must be so high that they can glide to earth “out of a spin.’ The best example of the airplane helicopter is the Berliner apparatus, the inventor of which— Emile Berliner—probably is the outstanding Amer- ican experimenter in this field of aeronautics. This machine looks exactly like an airplane and has the same fundamental lifting and control ele- ments. Instead of a single propeller in front, though, two horizontal Pescara’s invention executing a_ well controlled vertical flight. This machine recently flew 187 feet in a straight line and completed a circular course approximately 130 feet in diameter thousand feet. This it has not yet been able to do. The reason for this is that a tremen- dous force is nec- essary to lift any heavy object vertically, a fact well illustrated by the difference between trying to lift a barrel to a wagon and rolling it up on skids. When a helicopter first starts to climb, it is aided by the air-displaced by its revolving wings and reflected back against it from the ground. After it has ascended to a height equal to the diameter of its screws, however, this upward rush of air from the ground does not reach it. The machine then must depend entirely on its own power to overcome gravity, and no helicopter has proved capable of The DeBothezat helicopter, built for the U. S. government. ceeded in remaining stationary in the air 35 feet above ground for five min- utes, and has ascended four feet with two passengers and 17 feet with one It has suc- propellers rotating in opposite directions are placed above the wings outboard, and are driven by a bevel gear and shaft from an engine in the nose of the fuselage. A SMALL propeller with adjustable pitch, driven by the same motor and located at the rear of the fuselage, sup- plies forward motion. Lateral balance and control are provided by vanes placed under the propellers. These vary the thrust of the two propellers in what- ever direction it is necessary to tilt the plane. An early model of this machine E i 3 H OPES AANA Sh tS BORER ARAL ES 3 3 L E a

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ns rd, aft xe, sle nd ip- ce ed he at- he ne ; ' t ‘ was the first vertical lifting craft to make a controlled flight back to its starting point. HERE are many examples of the pure helicopter. One of the first successful machines of this type was that of Professor Von Karman, of Austria. At the top of this machine are two pro- pellers rotating on a common axis but in opposite directions, which balance each other and prevent the machine from rotating. The propellers are driven by three rotary motors located in a tripod- shaped fuselage. A recent model of this machine made some noteworthy altitude flights. In the cockpit is a parachute that opens if the motor fails, and causes the machine to drop slowly enough to assure safety for the pilot. Mr. Pescara, an Argentine engineer working in France, recently developed a machine that in many ways is similar to that of Professor Von Karman. This also has two screws rotating in opposite directions and driven from below, but there is only one motor. The inventor, moreover, has added a noticeable im- provement in a method of controlling the propelling screw. The pitch of the blades is varied throughout the rotation by means of a set of cams controlled from the pilots seat. By this method the thrust distribution can be shifted forward, backward, or to either side, and any tilting of the machine thus corrected. Flights of considerable duration have been made in this machine in the last few months. Another type of helicopter with a still larger number of unusual features is that developed by Doctor DeBothezat for the United States Gov- ernment. This ma- chine has four instead of three screws, and all are on the same level. Control is effected by varying the pitch and consequently the lift of opposite ele- ments through a center control stick. The machine obtains stability through an ingenious system of automatically bal- ancing the forces produced by the four screws ior a vertical lift. POPULAR SCIENCE MONTHLY complicated in its operating mechanism than an airplane. That is to say, a pilot must be required to use no more than two hand movements and one foot movement to obtain all possible movements of his craft. The machine must be designed, too, so that if the power plant fails, the mechanism will not be left unbalanced. These obviously are difficult conditions to meet. However, somewhat similar problems confronted the pioneers in the development of the airplane, and were solved successfully, so aviation engineers expect confidently that a practicable helicopter eventually will be produced. | REQUIRES no special technical knowledge to predict what status the helicopter will occupy in the aviation of the future. The helicopter will be used only where the flight is one principally of ascent and descent in a vertical plane; where taking off and landing are the main operations of the trip, and where only a small machine can maneuver with safety and convenience. Let us suppose, for example, that an airplane line were established between two big cities such as New York and Chicago. Huge airplanes, capable of carrying a large number of passengers, would be the logical units of transportation. By their nature these machines would be required to land in fields on the out- skirts of the cities. This would mean that some auxiliary method of transportation eae Von Karman’s helicopter taking off. This is an early model without the cockpit shown in the "pper picture. The propellers are driven by three rotary motors in the tripod-shaped fuselage M. Oehmichen, whose experiments in Paris have attracted wide attention, has a device similar to the DeBothezat ma- chine. It differs, though, in the stability System that depends on the gyrostatic action of a flywheel on the motor and the shape of the screws, which have narrow tips and wide hubs. A successful helicopter cannot be more would be necessary to carry passengers to the cities themselves. Automobiles would offer the most convenient method of doing this, but helicopters probably would be even better—assuming, of course, that the helicopter had reached a stage of development that made it just as safe and just as fast as the automobile. For the helicopter would be independent which illustrates the idea of opposed screws. The wing spread is 44 feet 39 of the delays caused by heavy traffic, and it could transport passengers directly to their hotels or offices, landing on the roofs of the buildings. Another important and perhaps a wider use will be for personal transpor- tation. In my opinion, there is a definite Held captive by cables, Von Karman’s _helii- copter established a record by ascending 150 feet with two men aboard. An unusual - feature is the position of the cockpit above the two horizontal lifting propellers future for the ‘“‘flivver’’ helicopter. No matter An American creation, to what P pie = t of the Perry helicopter, Tefinement flivver planes are developed, there always will be crowded districts in which it will be im- possible for them- to take off or land. The most congested city district would offer no terrors to the helicopter, provided there was a roof convenient for use as a landing platform. ‘Hat the helicopter ever will displace the airplane, though, is unthinkable. Airplanes and dirigibles are absolutely beyond competition where aircraft cap- able of long flights at high speed are re- quired for such purposes as the trans- portation of passengers, freight, and mails between cities. To lift itself ver- tically the helicopter has to pay in power expended for the purpose and in me- chanical complexities, both of which detract from its likelihood of becoming a craft capable of prolonged, fast flight. At present the experimenter in heli- copters finds his encouragement not in the possibility of immediate use of his invention, but in the opportunity to enter the competitions that are contemplated in various countries. Great Britain, France, and Italy already have arranged competitions, and the British event, which is to be held before next spring, of- fers attractive inc ucementsin prize money.

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40 POPULAR SCIENCE MONTHLY In the Vanguard of Science Keep in Step with Useful New Discoveries and Inventions “NOR years the telegraph has apprised us of the news of the world almost as the events have occurred. Now it also can show us pictures of far-off happenings with a speed little less than that required to transmit an account of them, for engineers of the American Tele- phone and Telegraph Company have per- As the ray passes through the film, its intensity constantly varies according to the lights and shadows of the picture, causing corresponding variance in the current that issues from a photo-electric cell. This current is transmitted along a wire to the receiving station, where the received current is transformed into fected a simple, commercially practical variations in a light ray. The ray method of sending is directed against a photographs by wire. photographic film, The process was . ain moving across it as N Physicists of the U. S. Bu- reau of Standards are shown above melt- ing thorium oxide, the substance used in making crucibles for holding molten metal, and that has resisted hitherto all attempts to melt it because of the terrific heat required for the purpose put to a thorough test during the recent Democratic and Republican conventions at New York and Cleveland respectively. Only two instruments capable of exchang- ing photographs by the new system are in existence, but the success with which the convention pictures were transmitted probably will lead to the construction of others, and sending pictures by wire eventually may become common practice. Both receiving and sending apparatus are adaptable to radio. "T*HE new process has for its basis a photo-electric cell, an apparatus the electrical conductivity of which varies according to the amount of light entering the cell. A positive film of the picture to be transmitted is placed on a revolving cylinder and a thin ray of light directed against it. This ray moves vertically across the film in lines that are 1/65 of an inch apart. the film on the sending cylinder is repro- duced exactly at the other end. Vacuum tubes and other auxiliary apparatus are required for long-distance transmission, but the foregoing will serve to explain the essential features of the process. It requires about 414 minutes to trans- mit a five by seven photograph by means of a ray that moves 65 times in an inch. This gives to the received picture about the same quality as a newspaper half- tone. By causing the light ray to describe more than 65 lines to the inch, the -iginal photograph may be transmitted more perfectly, though, of course, it would require longer. Artificial Breath 7 scientists appeared before the French Academy of Medicine a few weeks ago and placed on a long table the bodies of several animals. Some of the animals had been poisoned by carbon monoxide; others had been subjected to other deadly gases; the respiratory cen- ters of others had been paralyzed. All gave every external evidence of being dead and yet a few minutes later all of the animals were hopping about, appar- ently in normal health and none the worse for their experience. This seeming miracle was accomplished by means of a new apparatus designed to resuscitate victims of drowning or asphyx- iation. It consists of two bellows, oper- ated by an electric motor, one of which “exhales,’”’ the other of which “‘inhales” in a way that is said to imitate perfectly the action of the lungs. The artificial breath from the bellows is transmitted to the sufferer either by a Chlorine gas, used as a weapon of death in war, recently has come into use as an effective remedy for the treatment of colds. The view above shows officials of the New York City the ray moved on the sending film. Since the two films are of the same size, and the movements and intensities of both sending and receiving ray coincide, Department of Health witnessing a demon- stration of the new and effective treatment which will be described in detail in next month’s issue of Popular Science Monthly tube placed in the throat or through 4 mask that covers the face. This method is said to be more certain than any previous system of artificial respiration.

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Ly um are on, the ns- ans ch. out alf- “ibe inal ore uld the few the the bon 1 to cen- All ping 1 of par- the shed 1 to 1yX- per- hich 3” in ‘ the ws is ya igh a ethod any ation. i * 2 } { f : f A King of Locomotives AS A result of four years’ work and at a cost of more than $100,000, engin- eers of the American Locomotive Com- pany and the Delaware and Hudson Rail- road have produced what is said to be the most powerful steam locomotive. The new engine operates at 350 pounds steam pressure, while the average freight locomotive utilizes from 175 to 220 pounds. It has two small wheels forward, and four driving wheels, lacking the usual trailer wheels. This change in design is said to produce greater tractional force. Its smoke box is small, and the boiler is vir- tually hidden under a mass of heavy steam pipes. A novel feature of the compound engine of the new locomotive is that steam is utilized twice before exhaust. It is passed at high pressure into one cylinder, then led into a larger cylinder on the other side at slightly reduced pressure, then ex- hausted through the stack. The development of so powerful a steam locomotive is significant in these days when electrical and internal-combus- tion locomotives are attracting wide attention. It is remarkable also that the new locomotive util- izes an engine of the compound type, once discarded by loco- motive designers as “‘inefficient.”’ Photographing the Invisible IEUTENANTS MACREADY and Stevens of the Army Air Service ascended in an airplane 32,220 feet above Dayton, Ohio, a few weeks ago. At that height their airplane was invisible from the ground. When they looked down, the city was obscured by a blue haze that rose from 8000 to 10,000 feet from the ground. Yet they snapped their camera several times, and ob- tained remarkable photographs of the city—pictures in which the buildings, even the automobiles in the streets, were defined clearly. That they were able to make pictures of objects invisible to them was due to three actors—an extra long-focus camera, Super-speed film, and a “minus blue” ray filter that absorbed the ground haze. No aerial photograph ever before had been made from such a height as six miles, yet POPULAR SCIENCE MONTHLY In an attempt to explain the mysterious “zones of silence’? noted during the war and to determine whether there really are blank areas skipped by sound waves as they radiate, French army engineers recently set off a terrific explosion at La Courtine, France. The picture at the left shows the actual blast in which the experimenters used 10 tons of melinite, one of the most powerful explosives in the world. To determine the effect of the explosion on living bodies, dogs were tethered near the scene, as shown above. Paris, 275 miles away, neither heard nor felt the blast photographic experts of the Air Service say that the limit has not been reached. With a camera having a focal length of 20 inches, they say, clear photographs of the objects below are possible from a height of 48,000 feet—if airmen ever succeed in rising that high. An Aid to Super-Power | og England recently came word of the invention of a device that is expected to revolutionize the transmis- sion of electric power—a “‘transverter,” a combination transformer and converter, that changes ordinary low-pressure alter- nating current into high-pressure direct current. The new apparatus is the invention of W. E. Highfield and J. E. Calverey, en- gineers of the English Electric Com- Receiving a photograph. This apparatus is part of the new system for transmitting pictures by telephone, described on the opposite page pany, who had been engaged in its development since 1918. Engineer- ing experts in the United States have shown tremendous interest in the device, stating that it probably will further the super-power projects of this country by facilitating the in- terconnection of various power lines and power houses. Engineers long have dreamed of substituting high-voltage direct current in transmission lines for high-voltage alternating current, but to make the change was im- possible, due to the lack of a device that would convert the alternating current de- veloped by the generators into direct cur- rent. The new device makes the trans- formation; then, after transmission, a similar device steps the high-voltage direct current down to low-voltage alter- nating current for industrial purposes. Around the World in 17 Days Ee were vastly entertained when Jules Verne had his fictional hero, Phineas Fogg, make a circuit of the globe in 80 days, an exploit quite as fanciful as other feats that Verne had his characters perform. A commercial concern announces round-the-world trips by airship and air- plane in 17 days and causes no astonish- ment! A $5,000,000 company has been formed in London to conduct these tours according to the following itinerary: London to Paris to Constantinople by airplane; to Australia by airship; to San Francisco by airship; to New York by airplane; to London by airship. Bricks Made from Dirt OMPRESSED bricks made from ordinary dirt have been developed for house construction by two French engineers. In the process ordinary sub- soil earth containing five to eight per cent clay is compressed by tremendous pressure. The resultant bricks are said to have a pressure resistance of 600 pounds a square inch.

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42 Double-Locking the Door against Burglars DEVICE that, it is claimed, makes every ordinary door lock burglar- proof, consists simply of a small metal tongue to which is attached a small chain, pin, and screweye. In use, the screweye is inserted in the door near the lock and remains there permanently. When the door is locked, the metal tongue is inserted in the key- hole below the key. The pin then is slipped through the loop handle of the key and through a convenient opening on the end of the tongue. This keeps the key from being turned or pushed out of the lock from the outside. When the door is to be unlocked, the pin and tongue safety catch can be removed easily. POPULAR SCIENCE MONTHLY Inserting the pin in the key handle Telephone Arm Holds PRACTICAL telephone device con- sists of a holder for the receiver when in use, allowing freedom of both Above: The movable steel channel stalls. Right: How the skyscraper garage will appear Skyscraper Garage Will Park 600 Cars O RELIEVE congested parking con- ditions, a skyscraper garage, the first of its kind, is being planned for Chicago, Ill. It is designed to park between 600 and 700 automobiles and to carry the cars, without the aid of attendants, from the ground to the upper floors. The building is to be a 40-story struc- ture, including a tower. Part of 23 stories will be given over to garage space. Congestion will be eliminated by having entrances and exits at different levels. Entering, the car will be driven on to a platform, the engine stopped, and the owner given a check. Compressed air will raise the rear of the platform 18 inches, rolling the car on to an automatic electric elevator, which then carries the car to a floor above for storage. When the car reaches the floor desig- nated by an attendant below, the ele- vator stops, the gates automatically Receiver to Your Ear hands while telephoning, and a handy pad holder supplied with a clip so that papers of various sizes may be used. open, the rear of the elevator floor is raised and the car is rolled into its stall . by force of gravity. The stall consists of steel channels for the wheels and will be movable, so that when a car is run out from the elevator it may be slid away from the entrance, making room for the next car. The designers claim that hotels and department stores of the future may have their own garages incorporated in the buildings, A Wasp that Uses Tools HE definition of man as a tool-using animal may have to be revised. Dr. George C. Wheeler and Esther Hall Wheeler, of Syracuse University, recently reported having seen a wasp using 4 pebble for tamping down the entrance to her burrow. The incident happened in Texas, where the observers were studying insect life. Arrested by a loud buzzing, they caught sight of the wasp at work. The insect was holding the pebble between her mandibles and striking it against the ground by moving her whole body up and down after the fashion of a pile-driver. The scientists captured the wasp, but the pebble was lost in the excitement. St F OU} wit! be laid the us building by a fir By 1 shells fr and fro: driven ¢ thickne: to be ca they mu provide one leng Since materia! ground, necessar is excav F pressed which is driven. When } water is s make th ing by ¢ tive. A clean th B with cor crete co Thee fand bot reinforce

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is tall . ; of be out vay the and ave the Steel Pipe Foundations Filled with Concrete OUNDATIONS of steel tubing filled with concrete that, it is claimed, may be laid at a saving of time and cost over the usual concrete piers employed in building operations, have been devised by a firm of New York engineers. “By the new method, tubular steel shells from 1234 to 16 inches in diameter and from 3¢ to 1% inch in thickness are driven down to bed rock. The length and thickness of the shells depend on the load to be carried and the earth through which they must be driven. Cast steel couplings provide rigid connections when more than one length of tubing is used. Since there is little displacement of material as the shell is forced into the ground, previous excavating is un- necessary. The material inside the shell is excavated by a powerful jet of com- pressed air from a small auxiliary pipe, which is inserted after the tube has been driven. When the earth is extremely hard, i water is added to loosen the core and to make the tube airtight, so that the blow- ing by compressed air will be more effec- tive. After this, clear water is run in to clean the pipe. Finally the pipe is filled with concrete, forming a reinforced con- crete column. The concrete steel piles are set in groups and bound together at the top by a reinforced concrete cap. POPULAR SCIENCE MONTHLY irrigation by British engineers. It provides for regulating the flow of waters of the Indus River in India, to irrigate by seven great canals and tributaries the arid plains of Sind, including 6,000,000 acres of land now largely desert. To accomplish this, a great dam will be constructed across the Indus in the form of a double bridge more than a mile long, or five times the length of London Bridge. The upper bridge will be used for handling the gear operating the giant sluices, of which there will be 66, each closed by huge steel gates. The lower bridge will carry a public roadway. Building material will be of limestone from neighboring hills. The largest of the canals is designed to irrigate more than 2,000,000 acres. Alto- gether there will be 850 miles of main canal with branches, and more than 1200 miles of distributaries. The central canal will be half as wide again as the Suez Canal and its discharge The tubular steel shells are sunk to bed rock, as shown below. Then the material within the shell is blown out by compressed air, as at the left, and replaced by concrete The World’s Greatest Irrigation Project — ORK on the greatest project in history, the plan of which is shown above, was begun recently will approach the maximum discharge of the Thames. The cost of the dam will be more than $14,000,000, and the entire project will cost more than $50,000,000. The scheme was originated by Sir George Lloyd, Governor of Bombay from 1918 to 1923. An Automatic Policeman BSOLUTE protection for the auto- mobile and everything in it now is promised by a ‘“‘metal policeman” that sounds the horn as a warning signal as long as the car is molested. The burglar device, designed also to protect garages, barns, and similar build- ings, is an electric alarm with a secret switch. It consists of a series of electric contacts arranged in a metal box four inches square and one inch thick. When attached to a car it may be secreted under the hood. When the owner leaves the car he sets the secret alarm switch. There- after the slightest jar causes a spring to vibrate and make a contact. A small wheel with a series of notches on it is set into motion. Each of these notches makes a contact as it passes a copper spring, sounding the horn. The result is a series of short startling toots of the horn, which continue for 10 seconds. If the thief continues to molest the car, the process is repeated indefinitely.

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O DEMONSTRATE the importance of child hygiene education in the home, the Department of Health, New- ark, N. J., recently prepared a model ee | : Model “Health Street” Demonstrates Child Hygiene Work POPULAR SCIENCE MONTHLY street for a public health exhibition. All of the buildings were fitted with swing- ing fronts which, when opened, presented an interior of the rooms in each building, revealing the various types of educationa health work carried on in the home by the bureau. This method of visualizing the work aroused considerable interest, Champion Barrel Builder Makes 120 a Day (ge THESE days of dancing, whistling, and fiddling champions, there now appears William J. Murphy, of Massa- chusetts, who claims to be the champion barrel maker in the United States. He holds a record of making 120 bar- rels a day for 44 days straight, a total of 5280 barrels in all. Murphy, who is employed by a South Boston cooper, challenges all comers to dispute his title. Flappers in the South Seas HE bobbed-haired miss with henna- hued curls is not an _ exclusively modern product. On the Samoan Islands, native men wear their hair long. The women, however, cut theirs short and bleach it an auburn tint with a wash that is compounded from the leaves of a wild plant. Beauty spots made from alafa, a thin leaflike fungus, often are stuck on their foreheads and cheeks. These patches, which are phosphorescent, give the belles a striking appearance at night. New Fighting Tank Can Be Directed by Radio yee the army fighting tank now has radio ears and a radio voice. This doughty perambulating fort now can be directed accurately from behind the lines throughout a battle, a fact that the de- signers believe would increase its des- tructive power enormously in time of war. 3ecause of the deafening noise within a tank during fighting, a special design had to be developed. The tank shown at the right on the proving ground at Aberdeen, Md., was the first to be equipped with radio. A CAMERA that takes 250 pictures a second recently was developed by the U. S. Bureau of Standards to study the flight of projectiles from big guns. —__., ©vu.xv. New army tank equipped with radio “Strong Woman” Lifts Elephant for Charity O ASSIST a New York charity fair, a “strong woman” vaudeville per- former stopped the crowds at Times Square recently by lifting an elephant. The animal stood on a specially construct- ed platform, suspended by chains from straps slung over the performer’s shoul ders. Bracing herself on a platform with fet } wide spread, her hands gripping a hor- zontal bar on each side, the woman lifted the tremendous load. 8 .4 ol $+ £3 8A Bt { & ig se emt x y a. “9 i Street crowds watching woman performer lift an elephant hung from her shoulders ee So Er

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POPULAR SCIENCE MONTHLY waleaa Odd Motor Caravan on the Riviera Carries Its Own Canoe —* 7s latest style for a sight-seeing trip car not much longer than the canoe it the trailer resembled a great armored car. ccatenall on the Riviera is by motor caravan. carried on its odd top, drawing a very The strange caravan, canoe and all, is Vacationists at Cannes, France, recently large hooded trailer that served as a shown above just as it appeared in were startled by the sight of a diminutive covered home on wheels. In appearance Cannes. Great Hollow Tree Trunk a Natural Garage A HUGE natural garage in the hollow of a great baobab tree, was dis- covered recently by a motorist in Nyassa- land, Africa, shortly before nightfall. His car, a Ford, was accommodated handily by the high sheltered space. Despite its great hollow, the tree was alive. Earth’s Permanent Wave —.” the earth is a large wave that moves around the planet once every 8800 years, according to ; : one Ludovic MacLellan Mann, a member — ae a é ge rh of the British Royal Anthropological aie Pr or 6S Pa. iam Society. He says the wave moves the s sn = hitecd MEE He Bj position of the earth’s axis and poles arity A cnr eee ta & hele Gene slightly, resulting in climatic changes. r’s shoul m ° . Shipping a Mammoth Coast Defense Gun ae NE of the world’s largest coast de- weapon weighs 210 tons. A specially ig & Dor fense guns, recently shipped to New constructed car was necessary for trans- England, is shown below. The 16-inch portation and 50 men to move it. The world’s largest lamp, above, com- pared with the smallest, at right Smallest and Largest Lamps "T= world’s smallest and largest in- candescent lamps—one rated at about one quarter candlepower and the other at 100,000 candlepower—recently were exhibited by the General Electric Company. The large lamp, with a bulb 12 inches in diameter and 18% inches high, was developed for motion-picture studios. It is 1290 times larger than the average household lamp. The current required to operate three of these lamps would run the average street car. The small lamp, only a quarter of an i inch in diameter, uses but one-fifth of a sulders How the huge gun, weighing 210 tons, was shipped on a special flat car volt of electricity.

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POPULAR SCIENCE MONTHLY g te A O fi ‘ " oF lity, Sw SS = ee = Simple Card Index Aids in Quick Tuning LOTTED cardboard disks inserted be- hind the tuning dials of your set so that a portion of each disk is exposed to view, can be made to serve as a handy index for quickly tuning in any desired station, without the usual adjustments over a wide range. On small pieces of cardboard that fit into the disk slots are printed the call letters of the various broadcasting station within range. When a station is tuned in first, the card bearing its call letter is in- serted in a slot opposite the zero mark on the dial, as shown at the left of the illus- tration above. Thereafter, whenever you desire to tune in the same station, all that is necessary is to turn the dial until the zero mark is opposite the call letters on the card index. Liquid Resistance Used in New Grid Leak NEW type of grid leak differing from other types in the fact that it uses a liquid for its high resistance element, re- cently has been developed to eliminate microphonic noises. The new instrument is composed of a glass tube one-half inch in diameter and five-eighths of an inch long, about one- third full of liquid. At each end, on the inside of the glass tube, is a small semi- circular copper plate. As the grid leak is revolved in its mounting, the plates are gradually im- mersed in the fluid. In immersion, the grid leak has the minimum resistance of one-quarter megohm. When it is turned so that the plates are completely out of the fluid, it has the maximum resistance of two megohms. Thus the device can be adjusted for any resistance between these two points merely by turning it on its mounting. U. S. Navy’s Radio Messages Sent by Typewriter N THE U. S. Navy’s “radio central” station at Washington, D. C., has been perfected a teletype system by which an operator, simply by “typing’’ messages on a lettered keyboard, can transmit navy communications by radio from Washing- ton to San Diego, Calif. Depressing a key automatically transmits a dot-and- dash signal for that letter. Thus a navy operator, using headphones, as shown in the photograph below, can relay an in- coming radio message almost instantane- ously. This innovation is just one unit in a world-encircling radio system that now is being developed by the Navy Department. Two-Way Loop Aerial for Greater Selectivity NAN attemipt.to obtain perfect selec. tivity, an inventor of Brooklyn, N. Y,, has perfected an unusual combination horizontal-vertical loop aerial to be used with sensitive receiving sets. Tuning of the aerial is accomplished by turning the dial shown in the photograph below. This dial moves the vertical loop to the left or right, while the horizontal loop remains stationary. The inventor claims that despite strong interference from local stations, the com- bination loop will bring in distant stations at the slightest turn of the dial. Tuning the horizontal-vertical aerial Plants Listening In _ plant life ultimately be affected by the ever increasing radio activ- ity and the constant disturbance of the ether? This question recently has been put to scientists of the Smithsonian Institution and the U. S. Department of Agriculture. While they are not ready to offer a definite prediction, they point out that some, if not all plants are sensible to ether condi- tions and that these plants may be listen- ing in, just as are hundreds of thousands of human beings all over the world. A navy operator teletyping a radio message from the Washington station to San Diego, Calif.

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for selec. N.Y, nation > used - ned by graph al loop izontal strong e com- tations erial n affected io activ- e of the n put to stitution iculture. . definite some, if pr condi- ye listen- 1ousands rid. Thirteen-Tube Set Relays American Broadcasts ERTAIN American stations are heard with crystal sets throughout the British Isles, the programs being received and amplified by this new 13-tube set, at Biggin Hill, Kent, England. Programs on a 100-meter wave length, too low for most American amateurs, are caught by this station and relayed from nine broad- casting stations, each with a different wave length. The programs thus relayed have been heard as far west as Australia and as far east as Russia. A similar system for relaying British concerts is being developed for the United States. POPULAR SCIENCE MONTHLY ©u.&U Interior of British relay station Signal Travels 8500 Miles in a Split Second TH map below illustrates how, in 5/100 of a second, a radio signal recently streaked around an 8500-mile circuit; from New Brunswick, N. J., to Warsaw, Poland, and back to Nev York. _The round trip of the test signal was timed by a motion-picture camera actu- ated by a set tuned to the receiving sta- tion at Riverhead, L. I. This camera was in Washington, D. C., at a club where the observers were gathered. From this club the signal first was telegraphed to the sending station at New Brunswick, N. J. Thence it went.to Warsaw, and from there, after a 35-mile telegraphic telay, was sent to the Riverhead station. ATLANTIC OCEAN This map shows the 8500-mile round-trip course of the radio test signal IFFERING from the standard types of radio cabinets, this new six-tube set has a glass door at the top, through which the tubes are visible. This door may be opened to allow easy access to the rheostats placed between the tubes within. Two tuning dials are on the panel below. The inventors of this type of set also i eli nite Tahes Are Visible in Powerful New Set have perfected a new folding loop aerial, which they claim is wound in such a man- ner that the wires cannot be tangled or bunched. It is equipped with taps so that 10, eight, or four turns can be used, giving a range of wave lengths from 180 to 600 meters. This loop is said to be constructed as firmly as those that do not fold. Operates Six Head Phones from a Single Set _— several persons wish to listen in with separate headphones in- stead of a loudspeaker, some means must be provided to connect the various phones in series. This manner of connecting cuts down the volume on each phone. When only one or two persons wish to listen, therefore, it is advisable to take from the circuit the phones not in use, thereby increasing the signal strength in the phones in use. This has been accomplished in a very efficient manner by a radio manufacturer who has constructed a multiphone block in which a slider moving along a rod con- nects or disconnects from the circuit as many phones as are required. By using this device six persons can listen in, A CAMPAIGN to curb the howls and squeals from radiating radio receivers was launched at a recent meeting of the Inter- fering Radiation Conference, when it was decided to join forces with the American Radio Association in educational work through the large broadcasting stations. po — -O— Pid tv i Multiple block for phone connections Ammeter Battery Tests ESTING radio A batteries with an ammeter is not a satisfactory method of determining the best brand, according to George W. Vinal, chief of the battery section of the United States Bureau of Standards. Mr. Vinal explains that some of the very best and longest lived batteries do not give as high an ammeter indication in this test as inferior brands.

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POPULAR SCIENCE MONTHLY Mysterious Fire in jig teehee ey years after a creek bed in Philadelphia, Pa., had been converted into a paved street, a passing autoist noticed a slender curl of smoke rising from a slight crevice in the roadway, thus discovering a fire that probably will shatter all records for novelty and length of activity before it is finally subdued. Gage Measures Clearance for Balloon Tires SIMPLE wooden gage has _ been devised to determine whether your ear has sufficient clearance for use of balloon tires. The gage consists simply of a stick with holes at certain distances from one end, These distances corre- spond to what may be termed the radius of the clearance circle. A nail is placed in the hole correspond- ing to the size of tire the car requires and the point of the nail held to the center of the hub. If the end of the gage in Swinging around the nail as on an axis strikes the fender above, the clearance is inadequate. All the above measurements are made with a maximum load in the car. New Anti-Aircraft Gas GERMAN is reported to have in- vented an aerial defense gas that makes it impossible for any one breathing it to ascend higher than 6000 feet. Beyond that height the aviator’s lungs will burst. Paved Roadway Has Been Burning a Year This discovery was made last summer. The motorist turned in an alarm, a fire company responded, and has been on duty ever since, establishing what is very likely an endurance record for fire fighting. They will soon complete their first year on the job. When the road was laid in 1909, from 300 to 400 feet of the foundation was filled with cinders, coke, and other furnace refuse, and the highway laid over all. Fourteen years afterward the pave- ment was discovered to be a mass of fire. The cause is believed to have been spon- taneous combustion. It is thought that several red hot coals from the fill-in material that, in many cases, was dumped direct from power houses, became sealed in the great mass of waste. This bit of fire slowly smoldered and spread until it permeated the entire foundation, finally gaining the air, which fanned the pave ment furnace to fresh activity. Firemen have succeeded in digging; trench in part of the burning ma— through which a firehose creates a wal ® of water night and day, month afte® month. The fire probably will be allowed t burn itself out, which, according to & timates, will take about three or foy years more. Escalators for Salmon O SOLVE the problem of buildin a 90-foot dam in the Columbia Rive without blocking the run of salmon tha go up the river to spawn, model escalaton will be erected to determine whether the fishes will consent to this form of tran: portation. Excavating Shovel Swims to Work in Rive NSTEAD of dismantling a 22-ton excavating shovel in order to lower it from cliffs down to a dam at Eau Claire, Wis., engineers saved a week of time and expense by running the machine into the Chippewa River about a quarter of a mile below the dam and then moving it upstream under its own power. It had been planned originally to dis- assemble the machine and skid the parts out on a platform, from which they could be lowered by derricks to the river 70 feet below and then reassembled. To save time, however, it was decided to make the shovel swim to work, so the engineers put three men aboard and started it on its unusual and treacherous trip, in which it encountered deep holes, hidden ledges, and swift currents. At times the water almost reached the vital engine parts, but after 514 hour’ battling against the current, the shoved finally arrived at its destination and crawled out of the water like a huge hipp- potamus, to the great satisfaction of the men who conceived the idea. % | | The amphibious excavating shovel in midstream, bucking the current under its own pow? OV ndadcscsc.

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ir he pave ‘igging 3 Ve mag S a wal th afte owed ti 1g to & or fow 10n building bia Rive non that scalaton ether the of trans Liver make the neers put it on its which it n ledges, .ched the ¥ 14 hour’ 1e shovel tion and ge hippo yn of the POPULAR SCIENCE MONTRLY HE three planes shown above are painting the sky with colored writing over Hazelhurst Field, L. I. Traveling at Nite. Airplanes Paint | the Sky w ith a speed of 135 miles an hour, a camera man in another plane snapped this un- usual picture. Writing of Many Colors The new method of painting the heavens with all the colors of the rainbow is the invention of Major Jack Savage. Collapsible Rule Takes Inside Measurements COLLAPSIBLE rule designed to take inside measurements accu- rately consists of eight-inch sections, on the edges of which are grooves and H The collapsible rule partly pulled out Lake Steamers Carry IiE Great Lakes rapidly are becoming major highways for transportation of automobiles. Manufacturers are be- ginning to load large freight steamships with hundreds of cars at Detroit for shipment to distributing points along the runners that permit it to be pulled out for a short distance or to its full length of three feet. A spring catch holds each section when it is pulled out to the full. Mosquitoes Favor Cattle T LONG has been known that the mosquito is the only active carrier of malaria. Only one mosquito in 1000, though, carries the malaria parasite in an infectious stage, scientists of the Johns Hopkins School of Hygiene discovered in a recent investigation in Louisiana. They report also that mosquitoes show a much greater fondness for live stock than men. It will be difficult to convince any one of that at this time of year, yet the inves- tigators assert mosquitoes evidenced their preference in the following order: Horses, cows, dogs, pigs, human beings. Big Auto Shipments lakes instead of driving them overland or shipping them by rail. Some of the large freighters carry more than 300 cars at one load. The photo- graph below shows a load of automobiles from Detroit atthe Municipal Pier, Chicago. Part of a boatload of 300 cars on a lake steamer from Detroit at Chicago New Tip for Cutting Torch Saves Time and Fuel | Kevieneanpaearic designed for cutting heavy metals, a new tip for acetylene torches, recently developed, is said to effect a substantial saving of time and fuel by a new process of mixing the gases, preheating the cutting oxygen, and giving added velocity and penetration to the preheating and cutting jets. This mixing of preheated gases takes place in several passages in the seat of the tip. The gases then pass into a ringlike passage, where they are given a swirling motion and an additional mixing. They are separated again, and expanded into larger passages which lead to the openings in the end of the tip itself. The tip has the advantage of a renew- able seat that facilitates cleaning and maintenance and does away with the necessity of discarding or remachining used tips with worn seats. Results from tests, according to the manufacturer, showed a saving of 18 per cent. : ARSENIC has been found in appreciable quantities in all organs of the human body, increasing in amount with the age of the person examined.

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50 Could You POPULAR SCIENCE MONTHLY Save a Drowning Man? By Clifford Thorne, Veteran Life-Guard OST of us, some time in our lives, may expect to hear the terrified -~ eall for help from a drowning person; yet how many of us would know how to attempt a rescue? Every day in the United States about 20 people meet death by drowning, so the value of general knowledge of life-saving is obvious. Few of us, however, take the trouble to learn. Nearly 300 rescues have taught me that cool-headedness and a few simple, well- directed actions, rather than brute strength, are the chief requisites for life-saving. Most drownings are due to fear and excite- ment. I recall once, just at dusk, I heard a call for help, saw a crowd of excited people on the beach and a man strug- gling in the water. No one was going to his aid. I saw that the victim was not suffering from cramps and was keeping his head above water. So I shouted at the crowd for silence, drew the attention of the vic- tim, who was merely excited, and com- manded him toswim Fig. 1. in at once or I would order him off the beach for making a mer in distress. hold by pushing back the other person’s chin with both hands. The best way to tow a drowning person to safety is to throw one arm over his shoulder, across his chest and under the opposite armpit, as shown in Figure 5. Then swim on your back and pull him along. This hold will keep his head above water. An effective way to carry a swim- The -escuer swims face up Fig. 4. A neck hold can be broken by easily pushing against the struggling victim’s chin or nose with your hands disturbance. He immediately regained his self confidence and swam to shore unaided. If, however, you are forced to go into the water after a person, a few simple rules are worth knowing. First, forget about the so-called ‘‘death clutch.”’ Actu- ally, it is nothing more than a frantic effort of the drowning person to climb to the surface by using the rescuer as a ladder. If the rescuer will remain still a moment, the victim very likely will release Fig. 2. How to break a wrist hold. Press your knee against the drowning person’s arm Fig. 5. The most effective way to tow a drowning person to safety—a hold that allows freedom enough for swimming or at least loosen his hold. If necessary, one of several releases and grips may be used. F THE victim should grasp you from behind, wrapping both arms around your waist, as in Figure 3, simply stiffen your arms and raise them to the height of your shoulders, then duck out quickly. To break a wrist hold, use your knee, as in Figure 2, pressing it against the victim’s forearm. This will break the strongest grip. Figure 4 shows how to break a neck Fig. 3. To break a body hold from the rear, lift your arms_ shoulder high and duck out If the drowning person is wearing clothes, the most effective method is to grasp him from the rear. If the person will help a_ little, after being quieted by conversation, an excellent way to assist him in is to place one hand under each arm as in Figure 1, or on each side of the head, both of you swim- ming on your backs. T MAY surprise you to learn that stout persons are not more difficult to res- cue than lightweights. In fact, stout persons float more readily. Another _ surprising fact is that clothing actually aids you, be- cause of the air it re- tains for many min- utes. The first steps in resuscitation are to place the victim on his stomach, making sure to turn his face toward a current of air. Then clean his Position for resuscitation, as described in the accompanying article. Turn the victim’s face toward the air Fig. 6. mouth and nose. Now grasp him firmly at the belt line, as in Figure 6, and, hold- ing your arms stiff, sway backward, then forward and downward, exerting pressure on the abdomen. Release the pressure quickly onthe backward movement for the purpose of getting the lungs to work again. This should be done slowly, about 15 times to the minute. If you have an as- sistant, have him hold the victim’s tongue. Remember always to act quickly and calmly. Ae errors |

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POPULAR SCIENCE MONTHLY 51 > | New Inventions for the Housewife n’s son his the » 6. nim ove ‘ing s to the ‘son tle, ted an sist one arm r on ead, yim- ks. rise that not res- thts. sons dily. ising hing , be- t re- min- s in ep to 1 on king face it of 1 his 7 irmly hold- then assure sure or the again. ut 15 an as- yngue. y and Fruit or vegetables are sliced quickly simply by inserting them in this device. Pushing the handle forces them through a series of sharp, parallel knife blades tor BO x es * : - * a oe ‘ ‘ . sieictasactaaes ts csr an A padded spring above the wooden support of a dress hanger grips the garment firmly and holds it in shape This novel kettle, with detachable spout, is easy to keep clean. The spout is also equipped with a strainer Four electrical attachments—fan, radio, iron, and light—can be used at once froin one outlet by means of a new plug oh This compact dish-drying stand folds as shown below. When opened, wire racks hold the dishes, while a pan beneath holds the silver and the smaller articles This sanitary kitchen table combines drawers for utensils, a sliding bread- Doard, a towel rack, an adjustable seat, and a refuse pail An ingenious apple cutter and corer is so arranged An entire meal may be cooked on one burner, it is that it not only cuts the core out cleanly, but slices claimed, by using these four square pots of aluminum the apple in quarters at the same time. Simply hold that fit together over the flame. The inventor claims the apple against the knives of the device and press their use will result in a 75 per cent saving of gas

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N AUTOMATIC teaching device, designed to aid children to master fundamental facts and to train them in automatic thought processes such as addition and combinations of numbers, has been developed especially for use in the lower school grades. The device consists of a machine Fifty Years of Carving on Elephant Tusk MARVEL of patience and skill is represented in this beautifully carved elephant tusk on which a father and son worked nearly 50 years. The carving was done by Hindus. When the father who started the work died, the son carried it to completion after many more years of work. The tusk is now in the possession of a resident of Brooklyn. RECENTLY E. J. Campbell, of Thurston County, Washington, announced that through scientific processes he had de- veloped a stingless bee. The insect is said to give good honey. Automatic Teacher Drills Young Schoiars POPULAR SCIENCE MONTHLY holding a set of about 50 cards on which the drill facts are printed, a set of cards covering one subject and forming one unit. The cards are placed on the ma- chine, which automatically drops them in regular order at intervals of from one to three seconds. The child or class calls the answer to each card while it is exposed to view. Thus for drill in addition, each card bears a combination of numbers to which the scholars must quickly give the correct answer. The card teaching machine is designed also for use in Americanization evening schools. Subjects covered include lan- guage, civics, history, and arithmetic. Fourteen Instruments in One-Man Orchestra { (OMBINING 14 different instruments in one, a novel one-man guitar, when properly played, is said to produce the effect of a real jazz band. The instru- ments are played at the same time in order to give the effect of a full orchestre, The “band” was invented by Signor Miguel Juan, of Belgrade, Servia. He plans to bring his unique instrument tc America soon. How the combination instrument is played Camera Reveals New Marvels of Science MAZING new uses for the camera as an instrument of scientific research have been found in the last few weeks. At Ohio State University, Professor Wesley G. France has devised a micro- scopic motion-picture camera capable of photographing the movements of mole- cules in chemical action. With his ma- chine Professor France succeeded in making pictures of the ‘““Brownian move- ments” of particles of basic carbonate of lead, about 1/25,000 inch in diameter. The particles were immersed in fluid and their irregular jerkings as the fast- moving molecules jolted against them were plainly visible when the pictures were thrown on a screen and enlarged. Meanwhile two French scientists have demonstrated before the French Academy of Sciences a process of making X-ray motion pictures of the organs of the hu- man body. The throbbing of the heart, the action of the lungs and the workings of the digestive organs are said to be disclosed perfectly by this process. Another discovery, somewhat similar in application, has been made by Drs Evarts A. Graham and Warren H. Cole of the Washington University Medical School, St. Louis, Mo. This is an in- genious method of making X-ray pictures of the gall bladder that is said to furnish an infallible method of detecting gall- stones. Motorized Tailor Shop Calls at Your Door FFICIALS = and residents |¢iam of Washington, D. C., no longer need call ona tailor to get their trousers pressed. A_ tele- phone call will quickly bring the tailor’s ‘“‘wagon’”’ buzzing up to the door and complete tailoring equip- ment within the car will press suits while the owner gets an extra sleep. This car probably is the first of its kind. The tailor shop on wheels does ‘‘pressing at your door”’ ie So - | ae 7

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In l iments , when ce the instru- ime in hestre, Signor 1. He ent to Pesaiaiacaeecrr sehen ts have cademy ff X-ray the hu- . heart, orkings to be similar y Drs I. Cole Aedical an in- rictures furnish g gall- or Ancient Boats Come to the Automobile’s Aid RIMITIVE and modern methods were oddly linked recently when two African native sailboats were lashed to- gether in order to hold an automobile that was ferried to the island of Djerba, Tunisia, North Africa. After the boats were fastened to- gether, planks were laid over them crosswise and the car driven on top of them. Only one triangular sail was used Two native sailboats ferrying the auto to propel this novel transportation con- trivance, on account of lack of space. The trip was made without mishap and the natives seemed to enjoy trans- porting a white man’s “‘iron horse.” Sweeping the Clouds Away NDER some conditions aviators are able to brush small clouds out of the sky by flying through them repeat- edly. A fair sized summer cumulus or fair-weather cloud sometimes may be obliterated by about 20 flights through it. Sedan-Locomotive Runs on Railway Tracks A RAILROAD sedan capable of a speed up to 80 miles an hour was constructed by the Southern Railroad POPULAR SCIENCE MONTHLY HE largest and most imposing model ever used as an exhibit in a trial in the Supreme Court in New York City was recently constructed to portray a section of subway to the jurors hearing the suit for $1,400,000 damages brought Huge Subway Model Is Evidence in Court against the city by a construction com- pany. The model cost $8000 and is a complete reproduction of eight blocks of actual subway. Workmen spent the greater part of a day setting up the model. Baby “Wheelbarrow” Folds into Small Space Neos folding baby carriage is designed especially for greater convenience on a street car or in an automobile. It folds compactly into what resembles a large walking-stick with two rubber-tired Folded, the carriage re- sembles a heavy cane Co. by equipping an automobile body with flanged car wheels and a cow- catcher. It was built for use in inspecting tunnels and for emergency wreck patrol duty. There is no steering wheel and the operator mere- ly has to control the speed and ap- ply the brakes. The interior is lighted by elec- tricity and heated from the exhaust muffler. The sedan has complete equip- ment, including windshield, run- ningboard, fenders, The unusual railway sedan, showing flanged wheels and cowcatcher and headlights. Opened for use, it affords the baby a comfortable swing seat. Safety is assured by a strap that goes about the infant’s waist. The canvas seat is slung midway between the two wheels and the handles. Thus, in effect, the ingenious carriage is a small wheelbarrow. The metal frame is arranged so that the carriage may be folded easily. How the baby is wheeled City Lighting Laboratory ITH 44 different kinds of street lights in actual operation, Colum- bus, Ohio, bids fair to gain national fame as America’s street-lighting laboratory. Several cities have sent delegations there to study the demonstration.

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POPULAR SCIENCE MONTHLY Largest Arch Bridge Will Be Half a Mile Long HAT is to be the largest arch bridge in the world, costing over $15,000,- 000, will be constructed across the harbor at Sydney, Australia. will be 3770 feet, more than half a mile, wile the single arch in the center will The total length The Highest Irrigation Dam in the World a two years’ work on construc- tion, the Don Pedro dam, near Modesto, Calif., highest impounding dam Giant Amphibian to TWIN-MOTORED amphibian air- plane capable of taking off or landing on water or land is one of the new type of planes being developed for commercial in the world, has been completed and its waters are being used for the irrigation of 240,000 acres of land formerly useless for cultivation. The dam, which cost about $4,- 500,000, is 280 feet high, 1040 feet long, 16 feet wide at the top and 177 feet wide at the base. The reser- voir covers five square miles at an average depth of 280 feet. It is 14 miles long and has a maximum width of 414 miles. Three turbines capable of develop- ing 20,000 horse- power are installed in the power house. Carry 12 Passengers purposes by the Civil Aviation Depart- ment of the British Air Ministry. The plane is designed to carry 12 passengers, a pilot, and an engineer. A view of the new passenger piane, showing twin engines of 360 horsepower each Courtesy Messrs. Dorman, Long and Co., Ltd. : have a span of 1650 feet. The head room [S at high water will be 170 feet, allowing the largest ocean liners to pass beneath. A - Or deo wil Bank Chute Takes Money ki of Night Depositors O GIVE special service to patrons desiring to deposit money after bank- i, ing hours, a Philadelphia bank vault } k company has invented an_ ingenious safety deposit chute that leads from the at exterior wall of a bank building to the lo safety vault within. The outside opening Wi of the chute is covered with a bronze a door that can be opened only by the ; depositor who holds the key. * Whenever the outer door is opened, an sl alarm bell in the interior of the building i rings. The depositor simply unlocks the ” door, pulls down a trap, and places his pe bag of money in this chute, which carries th it immediately to the vault. The “ depositor then locks the outer door. The - entire proceeding is said to require less than 10 seconds. Special canvas bags fitted with padlocks are supplied to the depositors. A This system is designed to eliminate the problem of storekeepers, theater owners, and others who often find it necessary to keep large amounts of / money where there is no safe. Long Aerial Power Line ‘THE longest aerial power-line span, one of 6153 feet, is projected to carry electric power into Seattle, Wash., from across Puget Sound.

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trons yank- vault nious n the » the ening ronze r the d, an Iding s the 3 his arTies The The 2 less locks ‘inate eater nd it ss of span, carry from POPULAR SCIENCE MONTHLY Five Cars Carry Huge Pipe on Long Journey % int Fiat ts ‘ , digg ee ee ~ ad) im RECORD pipe shipment was made recently from Alliance, Ohio, to Orange, Texas, when one section of pipe with an inside diameter of 8 feet occupied five flat cars for shipping. Its total length was 124 feet and 60 men could stand in line along the top. This immense pipe is a creosote cylinder and its journey from Ohio to Texas took it over the lines of four railroads. The photo was obtained through courtesy of the Gulf Coast Lines. Chained Fountain Pen Is Useful in Public Rooms OR use in reading-rooms, hotels, libraries, banks, etc., a fountain pen attached by a small chain to a neat- looking cabinet furnishes a first class writing instrument always in working order. _The fountain pen is normally held up- right on the side of the stand. For use, a slight twist removes it from the cap and releases the body of the pen on the chain, which is fed from between two small roll- ers. When the desired length is obtained, the chain is locked by a slight pull to one side. After use a slight pull to the other side unlocks the chain, which disappears within the stand while the pen is re- turned to the cap. American Buffalo Return to the Western Plains A FEW years ago the bison, or Amer- can buffalo, of the Western plains, was threatened with extinction. Now, though, this danger is past. Where there were only 1100 head of bison in the United States and Canada 20 years ago, there are about 15,000 today—a fact that is due largely to the efforts of the American ison Society in stopping the wholesale slaughter of the animals. F°® traveling the heavy mud roads of New Zealand a concern operating motor stages equipped their cars with special contrivances for towing automo- biles out of mud holes under their own power. The device con- sists of a steel drum __ containing 500 feet of wire rope with a break- ing strain of four tons. This is mounted on the front of the car and is worm driven at the ratio of 96 to one by an aux- iliary gearbox at- tached to the main gearbox. By at- taching the cable to a stout pole and : Mud Is no Obstacle to New Zealand Auto putting the drum in gear, the car is said to be able to pull itself through any kind of road at the respectable rate of 100 feet in five minutes. Bridge Engineers Circumvent Mother Nature lw UNUSUAL engineering feat was recently accomplished near Pueblo, Colo., when a contractor was forced to assemble and rivet a 100-foot steel bridge on one bank of a stream and then pull it into place because mountain floods had twice washed away all the supports. The support work was hurriedly built, and a large tractor then pulled the structure into place by cable. This bridge, near Pueblo, Colo., was pulled into place by tractor and cable

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56 A Compact Outfit UCH of the pleasure of a summer auto-camping trip or a day’s outing depends on the arrangements you make for comfort and convenience at mealtime on the road. To provide these conve- niences in a compact form, a complete dining outfit, including table, chairs, food containers, utensils—everything neces- POPULAR SCIENCE MONTHLY for Auto-Campers sary for the outdoor meal—has been devised to fit into a metal case that will ride on the runningboard of the car. The large metal food containers hold food sufficient for six pecple for two days. The carrying case is used to form one side of the folding table. The case is supported at a comfortable height by How the metal case rides on the runningboard removable legs, and the table top is attached to it. Six chairs fold into a small packing space. When camp is broken, the complete outfit is quickly folded and packed into the case, which is equipped with a suitcase handle for convenience in carrying it back to the car, where it is strapped to the The complete outfit. The case forms a table-end runningboard. SS STH SSGAwWM WG rnp \ lt ~ Kno SS Sse ASO Re SOQ VaraBgg CESS. RHAGAHAMNIA LAG RAAT HEN steam begins to pour in clouds from the radiator of your car, it is a sure sign of an overheated engine. Such a condition often may result in serious damage, such as burned bearings or frozen pistons. If your en- gine overheats on the road, it is wise sal-soda. FPrrr proper grade. nor too lean. _ rer Fre When the Engine Overheats See that there is plenty of water in the radiator. Tighten the fan belt to assure brisk air circulation. Inspect the hose connections to be sure there is no leak. Drain, flush, and refill the radiator, then boil it out with Drain out the old oil and refill with a fresh supply of the Remove carbon from the engine cylinders. frequent cause of overheating. See that the spark is advanced to the proper point. Set the carburetor for a mixture that is neither too rich Make sure that the valves are not out of time. Inspect the muffler to see that it is not clogged. not to take the chance of continued driving. If you can’t locate the trouble, stop at least long enough for the engine to cool. Then proceed slowly and cau- tiously. When you get the car home, the best way to find and remedy the trouble is by the following procedure: Carbon is a Automatic Metal Laces Applied to Shoes HE interlocking steel lacing principle already applied to galoshes and to- bacco pouches, now is being used for shoes. When such shoes are first bought, the laces are tightened to fit the foot. After that it is necessary merely to slide a key up or down to “‘lace”’ or “‘unlace”’ the shoe. The automatic lacer is placed on the side of the shoe, which otherwise re- sembles the regular article. Substitute for Turpentine HEMISTS at the University of Wash- ington are experimenting with oleo- resin, a fluid found in pockets in the Douglas fir, in an effort to produce a substitute for commercial turpentine now obtained from our rapidly disappearing yellow pine. Attractive Flower Basket for Yard or Greenhouse HANDY holder for displaying cut flowers attractively in the yard or greenhouse consists of a wrought-iron rod to which is fas- tened a wire bas- ket holding a glass vase. The rod, pointed at the lower end, is inserted in the ground. A cast- iron plate at the surface affords a firm base when the rod is in the ground, andkeeps it from tilting sidewise. A hook at the top serves as a handle to be used in pulling the rod out, and a heavy coat of green paint preserves it from rust and at the same time : = adds to its at- The flower basket sup- tractiveness. ported by a metal rod SEE Rtaa crn nhl he aaa saa ty i!

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nciple nd to- >d for ought, » foot. 0 slide nlace” yn the se re- ‘ine Wash- 1 oleo- in the luce a ne now yearing ket se ng cut rard or ron rod et sup- AOE tc To Make a Balky Tie Slip through Your Collar O OPEN collars at the fold so that the tie may be slipped through easily when worn, an instrument known as a “collar cue’? has been invented. The collar is inserted on the fork of the cue and pulled through. A tongue spreads the fold. The World’s Largest Safe WwW is said to be the largest safe in the world has been installed in the new Fourth Federal Reserve Bank at Cleveland, Ohio. The steel ~stibule, or frame weighs 200,000 pounc hiie the door and the remainder of tu. gigantic vault weigh 300,000 pounds more. The vault is 13 feet square and has an all-around thickness of four feet of the toughest chromium steel, presenting a hopeless problem to safe-breakers. Light Paper Raincoat for Emergency Use ISHERMEN, hunt- ers, and hikers no longer need to be driven from their pleasures by sudden heavy showers. Emer- gency raincoats made of crepe paper especially treated will allow the fishing and hunting and hik- ing to go on without _ inter- ruption. When not in use the garment is folded into a small flat pack- age weighing but eight ounces. It is said to be rain- and windproof, affording ade- quate immedi- ate protection in all sorts of weather. fg, y The design of the new paper raincoat POPULAR SCIENCE MONTHLY Safety Tile for Stairs and Shops For stairways where the daily traffic of thousands of people scuff away the toughest of tread materials, necessitating frequent replacements, and where the danger of slipping accidents becomes a grave problem, there recently has been perfected a non-slip safety tile of an abra- sive material which is commonly used for grinding. The new product is intended specially for use in subway and railway stations, for ramps and factory floors where traffic is heavy, and for the floor in frunt of moving machinery where the operator’s mind must be on his work rather than on his feet. It is expected to lessen materially the danger to operators of power saws, planes, and similar machinery with ex- posed moving parts. The product may combine beauty with usefulness, for it holds unusual pos- sibilities in color combinations. Another tile very similar in construc- tion is useful to eliminate the hazard of slipping where smooth, highly polished tiles are used for walking surfaces such as the dangerous edges of an indoor swim- ming pool, the slippery floor under the shower bath, or the floor of a hotel washroom. Stair treads of the mat type are made by setting mosaic tiles 1 1/16 inch square in a reinforced asphalt composition. The picture above shows the use of the non-slip tile on a factory stair- way where traf- fic is heavy. At the left the tiles are shown in front of a ma- chine, to pro- vide sure foot- ing for the operator [t IS surprising how many fascinat- ing facts of science may be found in the most commonplace objects and incidents of every-day life. Are you in the habit of asking questions and finding the reasons for these apparently unimportant things and happenings, or do you just take them for granted? earth’s crust? . Why are tears salty? How Much Science Do You Know ? How much science do you know? The twelve questions that appear be- low offer you a chance to test your knowledge. Answer them to the best of your ability, then turn to page 119 for the correct answers. See how nearly you come to making a perfect score. 1. What is specific gravity? 2. Why does a shotgun kick when it is discharged? 3. Is it possible to make a perfect vacuum? 4. Why do some stars differ in color from others? 5. What is the commonest chemical element in the 6 7 8 . What is an electric spark, and what causes it? . What is the difference between heat and cold? 9, How can fish breathe under water? What part of the brain does the thinking? 10. What is fog and how is it caused? 11. 12. Why is the tiger striped?

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Baker POPULAR SCIENCE MONTHLY by meme Is an maven Fish Breeder by Day BAKER of bread by night, anda breeder of fish by day. Such are the odd titles of Louis Beldt, of St. Louis, Mo., whose voca- tion takes him to the bake ovens at 3 A. M. each day and whose avoca- tion has resulted in his recognition as an authority on fish culture and in possessing one of the finest pri- vately owned col- lections of rare and tropical fishes in the country. Beldt has found that in hybridizing A -P\3 bie! % : ¥ Pp Mei S which is found on ponds. This is a species of algae that grows on stag- nant water =§sur- faces.”’ Mr. Beldt has designed and man- ufactured an aqua- rium with a cast aluminum frame that he claims is an improvement over the old-style round fish-bowl. Such a bowl, he claims, results in high mortality among goldfish, be- cause it refracts the light and draws the heat, while the opening at the top is too small to al- or cross breeding different varieties of fish, a female will give birth to five litters, at intervals of two weeks, without having been bred a second time. He has discovered also that it is necessary to separate the sexes of the live bearing fish before attempting any cross breeding, for if they ever breed their own kind, they persistently refuse a mate of any other species. Fish fanciers and visitors from all parts of the country each Sunday file through Beldt’s home-built aquarium, in which he has over 50 varieties from foreign tropical waters, to see his collec- tion and to ask his advice on fish culture. ““Most people who begin keeping fish as a hobby believe that the water should Louis Beldt, St. Louis baker, in his aquarium, where he breeds fish as a hobby be changed frequently,” he says. ‘‘This is entirely false. The water in an aqua- rium need not be changed oftener than once a year if the tank is kept well balanced between fish and water plants. Plants give off the oxygen that fish need and the fish in turn produce carbonic- acid gas for the plants. Old water is clearer and cleaner than fresh. “Snails also should be added to the aquarium. They are real scavengers and devour all decaying matter, animal and vegetable. They even eat up all the excess food that you put into the aqua- rium. Snails will do away with the unsightly green scum that sometimes forms on top of the water, similar to that A Soundproof Cover for the Typewriter EARLY any standard typewriter now may be converted into a noise- less one merely by placing over it a soundproof typewriter cabinet that per- mits the use of the machine without the usual clatter of keys. The paper and writing are visible through a glass cover. Besides deadening the sound, the cabinet is said to protect the machine from dirt, dust, and accidental jars. How the OTE ROR case fits over the typewriter, which remains visible through a window low enough oxida- tion of the water. Mr. Beldt’s fish hobby has become almost self sustaining, and this baker of bread and breeder of fishes hopes soon to give up baking for good. He has orders for fish from all over the country. New Umbrella Folds into a 10-Inch Bundle STANDARD-SIZE umbrella de- signed to fold into a compact bundle 10 inches long and 2% inches in diameter is to be placed on the market. It is so small that it will fit into the coat pocket or into the smallest suitcase or traveling bag. The metal handle telescopes, the double set of ribs folds toward the handle and the outer section of the cover folds against the inner half. The top is folded by turning the telescoped handle a few turns. The opening is automatic. A few re- verse turns are all that is necessary to release the handle so that it may be extended, a spring within causing the top to open and pull the cover tight. Ne A day a towar tion wood count has b by the Comp the di ; means fully ; every ber ¢ knots. inerea ful ¢ each to 50 The accom saving aut body plank: bark tions F ando In 1 of kil size @ the y waste’ has h PF the s said usual type freer ing. Possil ina Venti from ished Th work, that

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on ae lg- 1T- vie he in be- cts WS the top al- da- ter. me of on has the de- idle eter $ SO New Cutting Process Saves Ford Huge Lumber Bill POPULAR SCIENCE MONTHLY SAVING of Am $50,000 to$100,000a day and a big step toward conserva- tion of the hard- wood supply of the country recently has been effected py the Ford Motor Company through the discovery of a means for success- fully utilizing every part of lum- ber except the knots, and thus increasing the use- ful output from each log from 380 to 50 per cent. bark left on. At right: Layout bench where The new method auto body parts are outlined on plank surface accomplishes this for sawing. Note how the irregular parts are ’ saving by sawing made to fit into the irregularities of the log Fautomobile | body parts direct from the unedged planks as they come from the log. The bark and sawdust are used in composi- tions that go to make steering wheels and other parts. In the past, bodies have been made out of kiln-dried boards sawed to uniform size and grade. By this method much of the youngest and best wood has been wasted. In the many cases where the log has been curved or irregularly shaped, the scrap has exceeded the mercantile Above: Sawing logs into parallel planes, with timber obtained. In the new Ford system, planks with the bark left on are cut from a log in parallel planes. These are sent to “layout tables,’’ where pat- terns for various parts are marked out until the plank 59 is covered completely with patterns right up to the bark. Irregularities are taken advantage of in laying out curved or irregular parts. Instead of trimming off a large piece to avoid a knot or check, the pattern men simply go around it. A high speed bandsaw then cuts out the various parts, following the markings. Under the con- ventional methods the actual produc- tion of board feet in aute parts, in comparison to the wood content of the entire tree, is extremely low. The limbs and top, representing one third of the tree, are wasted before the log gets to the mill. Only from 55 to 60 per cent of the log actually is converted into body parts. The best use found for the limbs and top has been to send them through the wood distillation plant. By the new process they are sawed up and used for body parts. Saw Grip for Paint Brush A NEW paint-brush handle shaped ~ Similarly to the handle on a saw, is said to eliminate strain and cramps usually experienced from the straight type handle, and also to allow a much freer arm and wrist movement in paint- ing. The shape of the handle makes it Possible for the hand to hold the brush ina relaxed natural position, thus pre- venting blisters. The tendency to slip from the hand is also said to be dimin- ished. The device was invented by one of the workmen in the factory of the concern that is now marketing the product. Gas-Tank Extension Facilitates Filling Y MEANS of a new device that is attached to the automobile gasoline tank under the front seat, the necessity for the driver to first remove the seat cushion before refilling the tank with gasoline, is eliminated. The apparatus consists of a flat alumi- num neck, one end of which is inserted in the gas tank. The other end, project- ing to the edge of the seat, has a non- leakable filler cap affording ready access to the tank, and gasoline gage that is always in sight. Three strips of wood are fastened under the seat cushion so that the filling neck will not bulge the frame. If WOULD take four months for an airplane flying 100 miles an hour to cross the United States if the earth were as large as the sun and its continents on the same scale. Filling the gasoline tank through the new extension without removal of the seat cushions iy Oe oe ahs. fc

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66 POPULAR SCIENCE MONTHLY “Horse’s Hoof” and “Shoe Sole” Reproduced in Rocks fF’ HE Darwinian theory of evolution [oes challenged recently by two al- leged fossils, one of a horse’s hoof and one of part of a human shoe sole, when they were exhibited to Eastern scientists by John T. Reid, a mining engineer of Lovelock, Nev. He is said to have acquired them from their discoverers. The first was found in Utah coal, which came from earth strata of the Cretaceous Age, millions of years older than the tiny three-toed Eohippus, from which evolu- tionists believe the modern horse evolved. If the object actually is a fossil of a horse’s hoof, it would prove that horses similar to modern ones lived millions of years before evolutionists believe the Eohippus lived. This would suggest very strongly that horses were created in the beginning as they are today. The supposed shoe-sole fossil was found in Nevada, in blue limestone from the Triassic period, which ended perhaps 100,000,000 years ago, ages before the appearance of the ape-like creatures from which man is said to descend. Evolutionists are certain that man has existed for not more than 500,000 years. If the object is what it is claimed to be, a strong pre- sumption would arise that man did not evolve from lower animal forms. The “shoe sole” These “stitches,” microphotographs show, are regularly spaced, and shoemakers have pronounced the whole apparently the work of a very skilful artisan. The surface js leather-colored. The “fossil” was termed by Dr. J. F. Kemp, professor of geology at Columbia University, and Dr. William D. Matthew, paleontologist of the American Museum of Natural History, in New York, “the most remarkable imitation of man’s handiwork by Nature’’ they ever had seen. | to be double stitching round the edge. A Substitute for Platinum LATINUM is even more valuable to the scientific worker than it is to the jeweler because of its power of resisting corrosion. Its cost, though, is so great that it must be used sparingly. Recently, how- ever, science has found an effective and very much cheaper substitute for platinum in cer- tain alloys of chro- mium and in iron electroplated with chromium. Any of these may be used for such purposes as sien tal oe serving for negative cand ie asst Shas. oop ll poles in electro- what appears to be double analytic work, also stitching around the edge. it is harder than Let: "The “porse oot fom” platinum, hence, hoof. Top: John T. Reid. en- likely to be harmed has what appears gineer, exhibiting the ‘‘hoof”’ by handling. Ripples of Sand and of Metal HE regular winds that sweep over the Sahara Desert create innumerable little ripples on the surface of the sand-dunes, as may be seen in the two upper illustrations. It is interesting to compare these miniature dunes with similar ripples that form in a piece of sheet metal shaped like a dune, swept by the violent rush of hot air from an acetylene flame, as shown in the lower picture. Microphoto Camera Attachment HE work of taking magnified photographs is simplified by a new type of microphotographic lens that can be attached to any standard hand camera. A small disk at the end of the lens tube holds the object to be enlarged. Ample illumination is secured from an electric-light bulb, and ordinary subjects require only a few seconds’ expos- ure. Magnification of 50 times or more is possible. (Stn PT Va ygy + At the left are ripples formed in metal by an acetylene torch The two up- per photo- graphs show sand ripples in the wind- swept desert LAMP ON STAND ‘ MICROPHOTO ATTACHMENT Above: Re- flex camera with micro- photo attach- ment. Left: Microphoto of plant bug; exposure five seconds. Right: Méi- crophoto of human hair ject tur ing to : all ope me of :

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cks > edge. 3 show, rs have 1e Work face js ae fae lumbia atthew, eum of 1e most \diwork ium able to to the esisting > great be used » how- ce has ffective much stitute . in cer- of chro- in iron d with Any of be used poses as negative lectro- rk, also or than nee, not harmed 1rent lified by ittached 2ct to be ric-light ;’ expos-

a eo ame WL} METAL CYLINDERS HOLDING ELECTRIC ™ onts < Ace a. ; = ja oS \ , . MOVABLE vite oa 2 PROJECTOR IREFLECTINGg PRISM

POPULAR SCIENCE MONTHLY SRE TES ak ee ee Oe et i ese m

Surgical Operation Projected on Classroom Screen ’ AN invention perfected by a B French hospital interne, the most delicate operations may be pro- jected and enlarged on a screen in a lec- ture room some distance from the operat- ing room. The projected picture is said to show every detail of the operation and all the objects in natural color, while the operating surgeon explains his move- ments to his distant ‘‘audience’’ by means of a loudspeaker. The invention has been made possible by a method of absorbing the intense heat of the lamps required to light the operation for its projection. Heretofore the harmful effects of this heat on the patient has baffled attempts at stereop- ticon projection. The apparatus consists of a series of metal cylinders containing powerful elec- tric lamps with metal filaments. These cylinders are cooled by water chambers, the upper and lower surfaces of which are transparent. The water is kept in constant circulation by a motor pump. An optical arrangement, including a projecting lens and a reflecting prism, is set from two to three feet above the field of operation, on which the light of the lamps is focused. By means of an adjust- ing arm the projector and lamps can be moved. <A microphone above the surgeon carries his words to the lecture room. Loudspeaker and Automatic Call Recorder for the Telephone WO remarkable automatic devices, both designed to do away with proverbial inconveniences in tele- phoning, have been perfected within the last few weeks. One is a “‘tele- phone telltale’’ which, in the ab- sence of its owner, automatically prints on a slip of paper the number of an in-

coming call. The other is a loud- speaker device to eliminate the neces- sity of “holding the line.”’ The telltale is a

At the same time the paper is fed forward for further operations. The apparatus can be controlled from

setting this wheel to required figures is determined from the caller’s own telltale indicating device, which points to figures corresponding to those to be printed on the absentee’s instrument. The annoyance of “holding the line’ for any length of time may be done away with by a simple form of loud- speaker operated by a micro- phone, which, in turn, is automatically energized by the telephone receiver. When the person at the far end of the line begins to speak, the vibrations in the receiver are conveyed to the microphone, which is connected TELEPHONE

rs | i; PAWL TURNS TVPE

clockwork attach-

ment connected with the bell mechanism of the telephone in- strument. The vi- brating movement of the bell causes a small type wheel to rotate under the control of the distant caller, thus printing the number on a slip of paper. The motive power for this operation is — derived from the operating movements of the bell spindle. A ringing period of three seconds will turn the type wheel through a complete revolution. The actual printing operation is controlled through a spindle above the mechanism. When the desired figure of the printing block is in position, the spindle frees the block that prints the required number. Above: The telephone loudspeaker system. Right: Automatic mechanism for recording and typing LEADS TO WHEEL WHEN BELL

= . ~ with a dry cell. ademas The emitted LOEVICE sound waves vary

the electric ‘Tresis-

MICROPHONE the central exchange or from the calling station. In the lat- ter case the operator gives the caller tem- porary control of the ringing current. The calls that set the type wheel are sent by means of a simple pushbutton. The duration of each ringing period for

SPRING BLOCK FOR | PRINTING CONTACT tance of the carbon particles contained in the microphone and set up fluctua- tions in the current from the dry cell. These changes op- erate the loudspeak- er, which magnifies the conversation sufficiently to be heard a_ consider- able distance. The apparatus is designed especially for use in a private office. CAM CONTROLS PRINTING BLOCK

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62 POPULAR SCIENCE MONTHLY How You Can Save Money in Building Your Home By Phil M. Riley Noted American Authority on Architecture and Building HOUSANDS of men and women in the United States today are asking themselves the question: “Can I afford to build a home?”’ The building of a home is an important event in the lives of most of us—almost as important as marriage and the birth of our children. For a home, we mort- gage our future and color the destiny of our loved ones. N AUTHORITY has A said truthfully that if all the waste in the construction of small homes in the United States could be eliminated for two years, the savings thus made would be enough to pay off our na- tional debt! Whenever a_ prospective home-builder comes to me for advice on how to save money in construction, my first thought is to let that state- ment speak an effective an- swer. For when you come right down to it, saving con- sists largely of cutting out un- necessary waste — waste in materials, workmanship, ar- chitecture, and waste repre- sented in spending more than you can afford on things you don’t need. “How can I build a small home and save money? How can I make my savings go further? How can I spend less money and get more in re- turn?” Thousands upon thousands of questions like these are asked every year by prospec- tive home-builders in the United States. No doubt, if you are contemplating a home of your own, you have asked the same questions. No doubt you have pictured your ideal home. You have set your vision down on paper. Evening after evening, with your wife or future wife beside you, you have planned and replanned, added and sub- tracted, shuffled rooms, closets, and porches about until at last you have created what you believe will be the per- fect small home for you. ND now it comes time to build. You look at your bank book, at the figure that represents months or even years of careful saving. You find that with the additional money you plan to borrow it still falls short, perhaps $1500 or so, of the cost of your dream home. “T guess it can’t be done,”’ you finally -concede. But it can. On an average $6000 home you actually can save in the neighborhood of $1000 in construction costs, simply by following a businesslike method of careful planning, cutting out waste, and eliminat- ing non-essentials. You can save money For that reason, if for no other, it behooves us to be sure that we are getting full value for the dollars we put into the home; that we make it a carefully considered ““Complete, and still have your ideal home from cellar to garret—not with all the little luxuries and trimmings you have hoped for, per- haps, but with every essential for conve- nience, comfort, and happiness. I know it can be done, because thou- sands of Americans in moderate circum- stances are doing it today. The secret lies first of all in getting the right attitude—in regarding home-build- ing as a business enterprise, to be under- taken in a businesslike manner. When you begin to look at it as an investment for your money, then only will you begin to realize that every dollar spent should produce full value in return. To save by preventing waste of ma- terial, workmanship and time, the first essential is to find an honest, dependable contractor whom you can rely upon as your responsible executive to carry out your plans within the price you can afford to pay. The contractor who will dishonestly substitute material of inferior quality at the price of durable material, or who will attempt to cover up vital errors in carefully prepared drawings and specifications, with a reliable contractor to carry them out,” says Mr. Riley, ‘‘are the chief requi- sites for saving money in building a home” investment rather than a ‘‘hit or miss”’ luxury. In this unusually informative article Mr. Riley tells you concisely how to make every dollar count for com- fort, satisfaction and happiness in your new home. construction and slipshod work- manship, may cost you hundreds of dollars. In fact, he may even turn your best-laid plans for sound investment into financial disaster. When you are ready to build, make inquiries and find out the reputable contractors in your community. From these you can ask for com- petitive bids, and thus you can bargain for the one who will give the most for the least money. Unless you are experienced in buying materials and _ handling labor, don’t attempt to build your home by the so- _ called “day labor’’ plan, that is, by letting the many sub-contracts for the work yourself. Your lack of knowledge is likely to lead you into costly disputes and into needless expense in the purchase of materials. OU are the owner and proprietor of the busi- ness enterprise that is to be your home. Let a single general contractor be your executive in charge of the work. He will be your ex- pert to buy your materials economically and to let the sub-contracts for such things as heating, plumbing and electric wiring: He is the man who will be re- sponsible for the correction of errors and for turning over to you the completed home in satisfactory condition, and at a cost within the original estimates. But you cannot expect to make your general contractor responsible, no matter how honest and conscientious he may be, unless at the outset you provide him with complete, carefully prepared plans and specifications to execute. F YOU take the time to study some of the thousands of little homes that go up overnight—homes that represent waste —you will find that a large proportion of them have been built in “hit or miss” fashion, from sketchy plans. Many of these houses have undergone change after change and extra after extra in the course of construction. All of this means higher building costs, disgruntled and disap- pointed home-builders. On the other hand, a complete set of ii by re home purse Batisf you ¢; tick | began hnd a 0 Cos hat t witho ard]; Fir:

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vork- Jreds even | for incial yuild, t the sin From com- S you 2 who r the ; you uying idling it to he so- plan, many work *k of 0 lead es and in the ry and . busi- 3 to be single > your of the ur ex- nically > such lectric be re rs and :pleted d at a e your matter 1ay be, le him | plans some of chat go t waste ‘tion of - miss” ‘any of ve after » course ; higher disap- » set of plans will more than offset their compara- tively small initial cost in the saving they effect. They eliminate costly guesswork, arguments, delays, and extras. Of course, with the home-builder who is trying to save every possible dollar, the natural tendency is to cut out as far as possible the cost for architectural ser- vice, plans, advice and counsel. This saving alone may amount to $200 or $300 _enough to pay for the heating plant, or for part of the plumbing. As a result it | has become a sort of national habit to dis- regard a building schedule. To meet this difficulty there are now | available to the home-builder inexpensive POPULAR SCIENCE MONTHLY the first-floor plans, which meant tearing away part of the foundation and rebuild- ingit. Then after the first rooms had been built and before the walls had been plas- tered, they thought the kitchen looked too small. So they had one of the partitions moved two feet. Afterward they added built-in closets and cupboards, an extra room, basement partitions, a glassed-in porch, parquet floor in the living-room, and a dozen other extras not called for in the original plans. HE final result, of course, was that they awoke to discover that instead of $6400, the cost of their completed home had mounted _ to $9000. And of course they had to plunge deeply into debt to meet their obliga- tions. And that wasn’t all. In the course of constant alteration and additions they had broken up their floor plans so that when they moved in they discovered they were possessors of a 63 siding. Or, if the specifications call for brick, the saving may be more than twice as great. Wooden shutters for your windows are not only ornamental, but serve a useful purpose, especially in summertime. Yet you don’t really need them, and you can add them later on. By doing without them now you can save from $50 to $100. Unless the fire laws in your community require fireproof material such as tile or slate for roofing, you can save money by using wood shingles. If the plain shingles are brush coated, the additional cost will be from $25 to $50, and if they are dipped it will be even greater; yet in this case the additional expense will more than pay for itself in durability. You certainly don’t want a leaky roof. Rather than sacrifice durable material it is better to do without some large item such as the porch, which can be added at any time, and which will save from $300 to $600, depending on its size and design. Certainly a glassed-in porch, however desirable it may be, is not an essential. It requires not only extra window sash, but interior trim, painting, and more ex- pensive flooring, all of which may cost you as much as $600. This sum you can save at a single stroke. | sie im | = REF |irABLE| gal ——s KITCHEN [5 ! iff LIVING eA inance) et iae ROOM Za V a 4s DINING a ROOM ad Floor plans of the house above, showing how space is economized yet dependable “stock plans” prepared by reliable architects and accompanied by expert advice. This architectural Service costs a nominal sum for each Principal room. In other, words, every home-builder, no matter how small his purse or his house, may obtain complete, atisfactory plans—plans that may have ost two or three hundred dollars to pro- luce—for only a few dollars. iP UT even when you have supplied your- self with a complete building schedule, you cannot hope to save money unless you tick to it rigidly. ave in mind a young couple who regan with excellent plans for a simple ind attractive six-room Colonial cottage 0 cost about $6400. They had figured hat this was the limit they could handle without financial embarrassment. Yet lardly wee the foundations laid than my oung friends forgot all about their edule of economy. First they changed their minds about An unusually economical six-room square house of simple design. It is of frame construction with brick base, exterior of stucco and shingle roof. * materials are used throughout Stock building o ©Architects’ Small House A small Dutch Colonial home with spacious inclosed porch. The plan calls for wide siding on a wood frame with shingle roof. Simple materials and inexpensive equipment should make this Service 28'4" house economical to build house that was crowded | KITCHE and inconvenient — a [|” Rance, [ai misfit from basement to f] ying ° garret. , ROOM DINING R This is an extreme vest ROOM | case, yet many home builders are tempted likewise to plunge into PORCH little luxuries and un- necessary extras that usually add up to an as- tounding total in the end. You will be surprised how much money you can save not only by firmly refusing to depart from your charted course, but actually by limiting your requirements, cutting out all items that you can do without for the present and that can be added some time later as your finances warrant them. Suppose, for example, you are to build a $6000 home. Your specifications, we’ll say, call for an exterior of stucco. You can save from $125 to $300 at one stroke simply by substituting an exterior of wood Architects’ Small House Service Bureau Compact plans call for no unnecessary breaks in the exterior In planning the foundation, you will have to be guided to a great extent by the building codes in your community. Unless restrictions prevent, a nine-inch founda- tion wall of brick or concrete, soundly constructed, will serve amply for a small home. You can save money by using this thinner wall rather than a 12-inch wall. A full cement basement is not abso- lutely essential. It is something that can (Continued on page 113)

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62 POPULAR SCIENCE MONTHLY How You Can Save Money in Building Your Home By Phil M. Riley Noted American Authority on Architecture and Building HOUSANDS of men and women in the United States today are asking themselves the question: **Can I afford to build a home?”’ The building of a home is an important event in the lives of most of us—almost as important as marriage and the birth of our children. For a home, we mort- gage our future and color the destiny of our loved ones. N AUTHORITY has A said truthfully that if all the waste in the construction of small homes in the United States could be eliminated for two years, the savings thus made would be enough to pay off our na- tional debt! Whenever a prospective / =: home-builder comes to mefor - advice on how to save money in construction, my first thought is to let that state- ment speak an effective an- swer. For when you come right down to it, saving con- sists largely of cutting out un- necessary waste — waste in materials, workmanship, ar- chitecture, and waste repre- sented in spending more than you can afford on things you don’t need. “How can I build a small home and save money? How can I make my savings go further? How can I spend less money and get more in re- turn?” Thousands upon thousands of questions like these are asked every year by prospec- tive home-builders in the United States. No doubt, if you are contemplating a home of your own, you have asked the same questions. No doubt you have pictured your ideal home. You have set your vision down on paper. Evening after evening, with your wife or future wife beside you, you have planned and replanned, added and sub- tracted, shuffled rooms, closets, and porches about until at last you have created what you believe will be the per- iect small home for you. ND now it comes time to build. You look at your bank book, at the figure that represents months or even years of careful saving. You find that with the additional money you plan to borrow it still falls short, perhaps $1500 or so, of the cost of your dream home. “T guess it can’t be done,” you finally -concede. But it can. On an average $6000 home you actually can save in the neighborhood of $1000 in construction costs, simply by following a businesslike method of careful planning, cutting out waste, and eliminat- ing non-essentials. You can save money For that reason, if for no other, it behooves us to be sure that we are getting full value for the dollars we put into the home; that we make it a carefully considered ‘* aa | Tre “‘Complete, and still have your ideal home from cellar to garret—not with all the little luxuries and trimmings you have hoped for, per- haps, but with every essential for conve- nience, comfort, and happiness. I know it can be done, because thou- sands of Americans in moderate circum- stances are doing it today. The secret lies first of all in getting the right attitude—in regarding home-build- ing as a business enterprise, to be under- taken in a businesslike manner. When you begin to look at it as an investment for your money, then only will you begin to realize that every dollar spent should produce full value in return. To save by preventing waste of ma- terial, workmanship and time, the first essential is to find an honest, dependable contractor whom you can rely upon as your responsible executive to carry out your plans within the price you can afford to pay. The contractor who will dishonestly substitute material of inferior quality at the price of durable material, or who will attempt to cover up vital errors in carefully drawings and specifications, with a reliab!e contractor to carry them out,”’ says Mr. Riley, ‘‘are the chief requi- sites for saving money in building a home”’ investment rather than a “‘hit or miss’’ luxury. In this unusually informative article Mr. Riley tells you concisely how to make every dollar count for com- fort, satisfaction and happiness in your new home. construction and slipshod work- manship, may cost you hundreds of dollars. In fact, he may even turn your best-laid plans for sound investment into financial disaster. When you are ready to build, make inquiries and find out the reputable contractors in your community. From these you can ask for com- petitive bids, and thus you can bargain for the one who will give the most for the least money. Unless you are experienced in buying materials and _ handling labor, don’t attempt to build your home by the so- _ called “day labor’ plan, that is, by letting the many sub-contracts for the work yourself. Your lack of knowledge is likely to lead you into costly disputes and into needless expense in the purchase of materials. OU are the owner and proprietor of the busi- ness enterprise that is to be your home. Let a single general contractor be your executive in charge of the work. He will be your ex- pert to buy your materials economically and to let the sub-contracts for such things as heating, plumbing and electric wiring: He is the man who will be re sponsible for the correction of errors and for turning over to you the completed home in satisfactory condition, and at a cost within the original estimates. But you cannot expect to make your general contractor responsible, no matter how honest and conscientious he may be, unless at the outset you provide him with complete, carefully prepared plans and specifications to execute. prepared F YOU take the time to study some of the thousands of little homes that go up overnight—homes that represent waste —you will find that a large proportion of them have been built in “hit or miss” fashion, from sketchy plans. Many of these houses have undergone change after change and extra after extra in the course of construction. All of this means higher building costs, disgruntled and disap- pointed home-builders. On the other hand, a complete set of b i plans tively effect argur Of is tr) the n as po vice, savin en for pi has b regar To avail: Flo yet | Dby r ) servi pring hom purse satis: cost duce you Stick bega: to ec hard! youn Fi

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y rork- reds even for ncial uild, ; the ; in ‘rom com- ; you - who - the you lying dling t to 1 S0- plan, many work k of . lead s and n the r and busi- to be single your yf the ir ex- ‘ically such ectric be re- 's and pleted lata . your natter ay be, > him plans yme of nat go waste ion of miss” iny of e after course higher disap- set of teres : ‘ cas plans will more than offset their compara- tively small initial cost in the saving they effect. They eliminate costly guesswork, arguments, delays, and extras. Of course, with the home-builder who is trying to save every possible dollar, the natural tendency is to cut out as far as possible the cost for architectural ser- vice, plans, advice and counsel. This saving alone may amount to $200 or $300 enough to pay for the heating plant, or for part of the plumbing. As a result it has become a sort of national habit to dis- regard a building schedule. To meet this difficulty there are now available to the home-builder inexpensive POPULAR SCIENCE MONTHLY the first-floor plans, which meant tearing away part of the foundation and rebuild- ingit. Then after the first rooms had been built and before the walls had been plas- tered, they thought the kitchen looked too small. So they had one of the partitions moved two feet. Afterward they added built-in closets and cupboards, an extra room, basement partitions, a glassed-in porch, parquet floor in the living-room, and a dozen other extras not called for in the original plans. HE final result, of course, was that they awoke to discover that instead of $6400, the cost of their completed home had mounted _ to $9000. And of course they had to plunge deeply into debt to meet their obliga- tions. And that wasn’t all. In the course of constant alteration and additions they had broken up their floor plans so that when they moved in they discovered they were possessors of a 63 siding. Or, if the specifications call for brick, the saving may be more than twice as great. Wooden shutters for your windows are not only ornamental, but serve a useful purpose, especially in summertime. Yet you don’t really need them, and you can add them later on. By doing without them now you can save from $50 to $100. Unless the fire laws in your community require fireproof material such as tile or slate for roofing, you can save money by using wood shingles. If the plain shingles are brush coated, the additional cost will be from $25 to $50, and if they are dipped it will be even greater; yet in this case the additional expense will more than pay for itself in durability. You certainly don’t want a leaky roof. Rather than sacrifice durable material it is better to do without some large item such as the porch, which can be added at any time, and which will save from $300 to $600, depending on its size and design. Certainly a glassed-in porch, however desirable it may be, is not an essential. It requires not only extra window sash, but interior trim, painting, and more ex- pensive flooring, all of which may cost you as much as $600. This sum you can save at a single stroke. An unusually economical six-room square house of simple design. It is of frame construction with brick base, exterior of stucco and shingle roof. * materials are used throughout Stock building | 26' O° 8: | 1 eo w REF |IrABLe| ht KITCHEN 1 il LIVING HE |Rance| r % ROOM " \ ~ . DINING ROOM 4 VEST 4 ” f. a A small Dutch Colonial home with spacious inclosed porch. The plan calls for wide siding on a wood frame with shingle roof. Simple Floor plans of the house above, showing how space is economized me yet dependable “stock plans” prepared | by reliable architects and accompanied by expert advice. This architectural service costs a nominal sum for each Principal room. In other, words, every home-builder, no matter how small his purse or his house, may obtain complete, satisfactory plans—plans that may have cost two or three hundred dollars to pro- duce—for only a few dollars. UT even when you have supplied your- self with a complete building schedule, you cannot hope to save money unless you stick to it rigidly. have in mind a young couple who began with excellent plans for a simple ~ attractive six-room Colonial cottage i oe $6400. They had figured that this was the limit they could handle a financial embarrassment. Yet lardly were the foundations laid than my young friends forgot all about their schedule of economy. First they changed their minds about ©Architects’ materials and inexpensive a ' aaiie equipment should make this Bureau house economical to build as be Be house that was crowded KITCHE and inconvenient — a [|”” RANGE | misfit from basement to LIVING on garret. ROOM DINING & This is an extreme Vest ROOM a case, yet many home builders are tempted likewise to plunge into poRCH little luxuries and un- necessary extras. that usually add up to an as- tounding total in the end. You will be surprised how much money you can save not only by firmly refusing to depart from your charted course, but actually by limiting your requirements, cutting out all items that you can do without for the present and that can be added some time later as your finances warrant them. Suppose, for example, you are to build a $6000 home. Your specifications, we'll say, call for an exterior of stucco. You can save from $125 to $300 at one stroke simply by substituting an exterior of wood Architects’ Small House Service Bureau Compact plans call for no unnecessary breaks in the exterior In planning the foundation, you will have to be guided to a great extent by the building codes in your community. Unless restrictions prevent, a nine-inch founda- tion wall of brick or concrete, soundly constructed, will serve amply for a small home. You can save money by using this thinner wall rather than a 12-inch wall. A full cement basement is not abso- lutely essential. It is something that can (Continued on page 113)

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64 The Last Word in Radio A Résumé of Important New Developments and Inventions By Jack Binns America’s Most Popular Writer on Radio REMARKABLE filament ma- terial that is expected to revolu- tionize vacuum tubes has been discovered in the laboratories of one of the big electrical corporations. It is pre- dicted that this material, when the ex- perimental work is complete, will permit the manufacture of a tube that will practically reach the goal all experimenters have sought to attain—cold elec- tron emission. Even in its present laboratory stage there is no visible glow from the filament when the tube is in operation. Ever since the three-ele- ment vacuum tube was first produced, experimenters have tried to eliminate the un- wanted light and heat that Side view of the thermoformer, showing ther- mocouples that are heated by electric coils, producing direct current for the radio set are by-products of tube operation. The only thing used in radio work is the stream of electrons shot off from the fila- ment of the tube. These form a pathway for the current to the plate. The problem of perfect tube efficiency has been to get this electronic stream without consuming energy in making the filament glow to a white or red heat. The first step toward the goal of perfect tube operation came with the oxide- coated filament. The next important step came with the introduction of the thori- ated-tungsten filament. Now we shall have a new filament. Its nature is still secret. There is much to be done with it before it can leave the labor- atories, but I am reliably informed that it will permit four times as many tubes to be operated off the same battery as can be operated with the thoriated-tungsten fila- ments. It means a really portable set. Radio without Batteries OR several years scientists in the big commercial laboratories have searched for a means of employing the ordinary house current to operate radio sets. The big drawback always has been the ob- POPULAR SCIENCE MONTHLY jectionable hum accompanying reception, irrespective of whether direct or alternat- ing current was used. Investigators have concentrated their efforts uponeliminating this hum. In doing so they overlooked one of the simplest remedies imaginable. The new thermoformer operating a super-hetero- dyne receiver of the largest commercial cabinet type from an ordinary electric-light socket voltage as well as to light the filaments, The remarkable feature of the invention is that it can be employed on farms or at other places where electricity is not avail. able. For use where electric-light eyr. rent can be had, the thermoformer has electric heating coils underneath the series of thermocouples. There is no reason, however, why an ordinary oilstove should not be substituted for these heating coils, Across the Sea “a, Washington! Js : Mr. Coolidge there? This is King George of Eng- land, talking from London!” The next miracle of radio undoubtedly will take the form of such a conversation flung across the ethereal path- ways over the Atlantic Ocean. The epoch-making day is now not far distant. Whenit dawns it will usher in a new triumph for American genius. The big British Post Office radio station at Hillmorton, near Rugby, now being con- structed, is to have a 200- kilowatt tube transmitter of the “side band” type. As soon as it is in- stalled, two-way communication across the Atlantic by the two-way system in- vented and developed by Ameri¢an en- gineers will be made possible on a prat- tical basis. The wonderful thing aboutit is the ease with which radio and land ee ars Interior view of the University of Illinois’ radio laboratory, where experiments are being conducted that may revolutionize broadcast This remedy has been discovered by R. E. Sabin, a chemical engineer, in the invention of an apparatus called the “thermoformer.”’ It relies upon the fact that heat will generate electric current, if two dissimilar elements are joined and heat applied at the point of their junction. Such current is absolutely steady and uniform. Each unit of two such ele- ments is known as a thermocouple. The device can be used to supply B-battery transmission by eliminating the carrier wave, preventing the interference of “‘squeal’’ radia- tion from receiving sets, and reducing costs line telephone systems can be hooked up together and function automatically. When the British station is ready; you will be able to talk to friends ™ England over the ordinary telephone ® your home. Conversation across the Atlantic he been carried on daily for more than a yea: It has been a one-sided affair, however because the only transmitting station B the one at Rocky Point, L. I. oe inma ae ak oe

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ments, rention S OF at t avail- 1T Cur- ler has e series reason, should ig Coils, ea ton! Is there? of Eng- yndon!” f radio ke the -Tsation al path- Ocean, day is W hen it 1 a new genius, st Office morton, ng con- a 200- litter of it is in- . across stem in- ian en- a prac: about it nd land ad i graphs by radio, and some for television— 4] Reginald Gourand, of Paris, France, the method that some day will permit us H at work on a radio transmission set, to see distant events by radio. : r 4 ’ which he claims will be powerful a ae enough to permit President Coolidge . i 5 ' and President Millerand of France to Secrecy Is Promised Lt d exchange greetings across the Atlantic ECRECY in radio communication is has been designed to operate on said to be achieved in a system re- wave lengths of 80 and 100 meters. cently exhibited by John Hays Hammond, wave, The first of these has been in- Jr., before officials of the Italian Gov- nei stalled on the airship Shenandoah. ernment. The method also is said to _ It is operated by a 24-volt storage permit the simultaneous transmission of = battery, which will insure several more than one message on the same wave > hooked hours’ transmission in emergencies. length. natically. a During normal use the battery is These effects are said to be produced by ; ready, kept charged during operation. It utilizing several super-audible waves to riends will be used chiefly for radio-tele- modulate the carrier wave in a combina- phone » wit graph communication of the con- tion known only to sender and receiver. : : tinuous-wave type. Only receivers tuned to this combination antic has care doe ry vege i For short-distance telephone can receive the signals, and, since the pos- an a yeal. can be used effectively for peciniaten and recep- communication, as when landings sible number of combinations of wave however, ‘ion of messages several thousand feet underground are to be made, it will supersede the lengths is infinite, the chance of other re- station 8 in a mine. The photograph above shows transmit- mainset. Bothsets canbe operated . ceivers picking up the message is virtually POPULAR SCIENCE MONTHLY 65 ship is flying or hovering in the air. By the way, radio will assume a very important réle in navigating the new air- skip ZR-3 across the Atlantic this fall. Inventors Are Active HE feverish energy concentrated on the problems confronting the devel- opment of radio is illustrated in the rec- ords of the U. S. Patent Office. A year ago radio patent applications swamped that overworked institution, and threw it into a state of chaos. At the present time approximately 40 ‘ m This giant super- Improved Transmission _ heterodyne receiver, x operating on 8, 9, 11, VER since broadcasting became popu- __ of 14 tubes, was de- lar, the attention of almost every ‘signed by F. R. has been concentrated on re- Greene. an amateur radio fan has : of New York City. ceiving apparatus. Improvements in _ The set requires no transmission have passed by almost un- agp — Ragin a * * * and canno' ope- noticed, despite their great importance. said ak be There can be no quality reception unless eight vacuum tubes the transmission is equally good. Experiments recently made in the Uni- versity of Illinois’ radio laboratories may change the entire system of broadcast transmission by eliminating the carrier wave. Greater efficiency possibly will result from the new system, but more im- portant than all else will be the elimina- tion of “‘squeal’’ radiation. Radio and the Airship XPERIMENTS-~ with _ short-wave radio by the engineers of the U. S. Naval Research Laboratory under the direction of Dr. A. H. Taylor, have been so successful that a special transmitter i rs 4 A remarkable new substitute for the radio B battery, shown above, is attached to an electric-light socket. It is known as the *“‘super-Ducon,” and is the creation of Harry W. Houck (right) a radio engineer. The apparatus Mr. Houck is holding is an early form of his invention. William Du- bilier, famous radio inventor, is seen at the left demonstrating the invention in its final form. The device can be used with either direct or alternating current, and is said to consume less current than an electric light. It is composed of a rectifier and a simple arrangement of resistances and condensers to filter out the hum of the current from the lighting circuit patent applications reach the radio divi- sion of the Patent Office every week. In addition, about 50 amended applications are filed each week. The trend of the times is emphasized in the fact that inventions relating to radio transmission are very heavy. There also are many inventions relating to the transmission of photo- ting and loudspeaker receiving sets in a mine - ° F . ‘ - simultaneously while the big air- _ nil.

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66 POPULAR SCIENCE MONTHLY How to Build a 5-Tube Loop Set By Joseph Calcaterra Radio Editor POPULAR SCIENCE MONTHLY ERE is a set that reduces static to H a minimum, reduces interference from other stations, and insures improved tuning. It offers distance and volume without the necessity of an out- side aerial. It is an excellent set for the crowded districts of the larger cities. A small inside aerial system offers selectivity and enables the operator to tune station to station without interfer- ence. The directional characteristics of a loop also serve to eliminate static noises and interference from poorly operated near-by receivers. The set uses two stages of tuned radio- frequency amplification, a detector, and two stages of audio-frequency amplifica- tion. It is adaptable for use either with an indoor aerial consisting of 10 to 30 feet of insulated wire strung through the rooms of an apartment, or with a loop aerial. The circuit calls for five tubes. Storage- battery tubes give best results. Number 1 is the aerial post; No. 2 the ground post; No. 3 the tuning coil, con- sisting of 60 turns of No. 22 d.s.c. wire wound on a tube three inches in diameter and three inches long. Taps are taken at every 10 turns, the taps being arranged in a line down the front of the coil. UMBER 4 is a double-circuit jack. A and D are the outside springs; B and C the inside springs. Numbers 5 and 6 are inductance switches. Switch 5 is provided with seven switch points; switch 6 with eight switch points. Two switch stops are provided for each switch. Number 7 is a standard potentiometer, preferably of 400 ohms. Number 8 is a .0005-microfarad (approx. 23 plates) Ver-

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Arrangement of parts of the same set, showing the complete wiring terminal for the radio-frequency stages. Numbers 13 and 16 are radio-frequency variotransformers. Ordinary fixed trans- formers may be used instead, but will not give as good results. Numbers 15, 19, and 24 are six-ohm rheostats. Number 17 is a combination grid leak and condenser. The grid con- denser should have a capacity of .00025 microfarad, while the grid leak should have a resistance of from two to five megohms. Number 20 is the positive B-battery terminal for the detector stage. Numbers 21 and 26 are standard audio-

Here the parts of the set are numbered and let- tered to correspond with the symbols in the wiring diagram. The tuning coil, 3, is placed at the side of the receiver to expose taps and switch points nier variable condenser. The terminal of the stationary plates is marked A, while the terminal of the rotary plates is marked B. Number 9 is a one-microfarad fixed eondenser. Numbers 10, 14, 18, 23, and 28 are the vacuum-tube sockets. The filament ter- minals of the sockets have been marked F, and F,. Number 11 is the negative B-battery terminal, consisting of a soldering lug and screw in place of the usual binding posts. Number 12 is the positive B-battery

frequency amplifying transformers. The gridreturnterminal is marked A, although in many transformers it is marked F. Numbers 22 and 27 are standard double- circuit jacks; No. 29 a standard single- circuit jack; and No. 25 a battery switch. Number 30 is the negative A-battery ter- minal; No. 31, the positive A-battery terminal; No. 32, the positive B-bat- tery terminal for the audio-frequency am- plifier stages. bevy first step in wiring is to connect the corresponding switch points 5 and 6. Connect the two top switch points of each switch; then, going down the line, connect one switch point of switch 5 with the corresponding switch point of switch 6. Since there is one more switch point on switch 6 than on switch 5, this extra switch point will be left unconnected. This is the “blind” switch point on which switch 6 is set when it is to be disconnected from the coil. Now place the coil in position in front of switch points. The top of the winding is connected with the wire connecting the first two switch points of both switches. The other taps down to the end of the (Continued on page 116)

' . pi3c 6% P plies \ Alas 1s F \ 718 FIG ear ir ‘ \\ B xs SA\\\ “Pl CSE] Pues 3 Ps A ] ] je 5 <4 B ioe i. 9 ; (tes 2 — Y = CeO UU UUUUUUL Ups ‘ Oe

Wiring diagram, with symbols numbered and lettered to correspond with photograph

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The ugh iz ble- gle- tch. ter- tery bat- am- nect and s of line, with itch oint xtra ted. nich sted ‘ont ling the hes. the SE aes Sy Sar tae ; ‘ : Sas TENS SS het ahr Eee eee By Fred A. Moss Assistant Professor, George Washington University quiet country highway, serenely en- joying the beauties of nature, when suddenly from a _ shaded side lane a runaway horse dashes madly into the path of your speeding machine. Will you have the presence of mind to put on the brakes and pull over to one side to avoid a crash, or will you be frozen to inaction for the brief second that will be your time margin of safety, and apply the brakes too late? If your wife is driving, will she scream and put her hands to her face, or will she do the right thing? How correctly will you or she act under the stress of unexpected circumstances? To determine this accurately, we con- ducted scientific psychological tests re- cently at George Washington University. These tests showed that, generally speaking, a man is a better driver than a woman, and that a young person usually is more efficient than his elders. These conclusions were reached by means of a new device for testing human emotional reactions under emergency conditions similar to those actually en- countered on the road. They were de- veloped to discover a means of increasing traffic safety for both pedestrian and driver by cutting down the number of incompetent drivers who have the law’s sanction to operate automobiles. I recently examined a _ 19-year-old youth who was a driver of a five-ton truck. I found he had the mentality of a seven-year-old and could not recall the name of the firm he was working for! He simply knew he could find his way to the place whenever he tried. Yet this boy had a license to pilot a five-ton engine of death through the streets of Washington! [siete yourself driving along a N OUR experiments we found that there were four sets of tests that an applicant should meet before receiving a card entitling him to drive a car. The first should be physical, to deter- mine that the applicant has normal arms, legs, feet, and at least one good eye. Vision should be carefully tested as to keenness and color perception. Further eyesight tests should be made for side vision to indicate the clearness and POPULAR SCIENCE MONTHLY The author in his labora- tory, tabu- lating emotional tests of drivers 67 What Would You Do in an Emergency? New Scientific Tests for Motorists response and his success in keeping the pointer on the white light denotes his alertness. test. This is the first part of the Next, an emergency is prearranged to come suddenly and without other warn- ing than the statement, at the beginning of the test, that ‘‘during the examination something is going to happen to call for range of applicant’s view to right and left. The second should deal with hearing. For a deaf person to drive a car efficiently. is out of the question. A driver must be able to hear the approach of fire apparatus in abun- dant time to enable him to get out of the way. He must also be able to hear the whistle of traffic police- men, ENERAL intelligence tests should come next. There should be several forms of tests that should be varied continually so that the applicants may not be coached by some one who already has_ taken them. The fourth test, one that so far has been neglected entirely, is that of emotional efficiency. To find this out we developed a machine that places the applicant face to face with some of the unexpected happenings of traffic. An _ individual test at this machine, in a minute and a half or less, will show just what mental reactions occur under emer- gency, and indicate the relative strength of the in- telligence and the emotions. This machine has for its central feature an ordinary auto steering wheel, rigged up to reproduce the actual guiding of a car. The turning of the wheel is indicated by a pointer that reproduces the changes in direction. The roadway ahead is indicated by two red lights, each light indicating an edge of the roadway. A white light between them indicates the exact center, which the driver is supposed to follow. These three lights are fixed in a frame that is moved to right or left by the men in charge of the test, the movements rep- resenting ‘‘curves” in the imaginary “road.” The driver follows the “‘curves” by keeping the pointer directed at the white light, and since he cannot foresee the shifts of the “road,’”’ he must pay close attention. The promptness of his road. hands, “‘ditching the car,” The ingenious machine used to test a driver’s reactions in an emergency. In front of the driver is a series of shifting lights indicating the roadway. The emergency is created by flash- ing a headlight in the driver’s face in such a way as to simu- late the light of another car emerging suddenly from a side In the test shown above the driver threw up her thus disqualifying herself sudden action.’”’ This emergency is fur- nished by a headlight, thrown toward the ‘‘driver’’ by thé release of a trigger. The headlight swings down toward his eyes from above in an arc representing 90 degrees of a circle. As it approaches on the level of the subject’s eyes, this head- light simulates a car shooting out from a side street or alley. HE test consists of the ‘“‘driver’s” reaction to the approaching “car.” Jamming a “foot brake” stops the flight of the lamp, or the approach of the “‘car,”’ at any angle between 1 and 90 degrees, depending on the speed with which the brake is applied. The promptness with which the “brake” is used measures the speed of the subject’s reaction and his level-headedness in an emergency.

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68 This measurement is in degrees on a scale that runs from one to 90. Some drivers stop the light at from 50 to 60 degrees. Others stop more slowly. Still others release the wheel and throw up both arms. When a person does that, even though he has passed all other tests satisfactorily, we know at once that he is totally unfit to POPULAR SCIENCE MONTHLY country. Persons in the fourth class should not receive a license at all. In the last classification, feeble-minded drivers constitute a grave menace. I believe that the feeble-minded represent the largest class of those who have licenses to which they are not entitled. The most dangerous defect encountered prompt turn of the wheel, or a quick jump to one side would have prevented the tragedy. This is a typical instance of slow mental response. Both women were frozen into inaction by the emotional stress of impending disaster. Motor traffic problems have reached such an acute stage that they demand new and advanced drive a car. We have a reliable mea- surement of his emotional efficiency, and the likelihood of his failure to meet an emergency. O THROW up the arms in such circumstances means either ditch- ing the car or a col- lision. Out of 105 subjects, three or four have thus “ditched the car’ and two have ac- tually given up at- tempting to drive as a result of this rev- elation of their un- fitness. These tests. of the individual’s behavior under care- fully arranged ex- perimental con- ditions show that a man in an _ emer- gency is much more likely to keep cool than a woman. This inborn tendency is due to man’s greater physical strength and his greater familiarity with machin- ery. A woman, on the other hand, is natu- rally more emotional than a man. A “close cal’ in a car, which necessitates extremely quick action on the driver’s part, often completely unnerves a woman for the rest of the trip, or causes her to faint. IMILARLY such a scare will make many women “afraid to drive any farther,’”’ a tangible and highly important consideration, for fear leads to terror, and terror to paralysis. It is not an uncom- mon thing for a person to become so frightened that he or she cannot speak nor make a movement. This is the paralysis of fear. Our emotional efficiency device was designed and built by Edgar Graham, an experienced aviator. Mr. Graham places drivers in four classifications: (1) The person who is safe under all conditions. (2) The one whose reactions are correct but slow, although capable of being speeded up by training. (3) The one who is all right except in congested traffic. (4) The one who, on account of mental! or physical disabilities never should be allowed to drive at all. The person in the first class is the ideal driver. The second class includes the man who has the makings of a good driver, but who must train himself into safe driving through prolonged practice. The driver in the third class should be restricted to the free zones or open This apparatus, which tests the basal meta- bolism of the human body—that is, the amount of oxygen consumed and the amount of carbon dioxide given off — has been em- ployed recently to determine whether an 3 en in examinations is that of slow mental response. A short time ago on one of the busy streets of the city of Washington, a woman driving a small sedan was moving forward about 15 miles an hour. As she approached a crossing, a woman stepped suddenly into the path of the car. Neither woman made an effort to prevent an accident. The car kept on and the woman on the street was killed. A The perimeter test to determine a driver’s ability to distinguish colored lights to the right or left. The average subject, says Mr. Moss, sees the light at about a right angle from the forward line of vision, but does not distinguish colors until the light is well toward the front. Blue and yellow are seen first methods of tests for sight and hearing, which are impor- tant attributes in emotional efficiency, Periphery vision, or the ability to see to the right or left, is of the utmost im- portance in driving a car. The safe driver must be thor- oughly aware of what is approaching from the side. He also must be able to recognize colors of signals in his side vision. O TEST this we devised a spe- cial perimeter. This instrument is rough- ly described as a band of steel curved into a half circle at- tached to a frame automobile driver is intoxicated. person is drunk, the chemical action incidental to breathing is increased and consequently the amount of carbon dioxide given off is greater than that from a normal in its center and marked off in de- grees from one to 90 on each side. It is held before the eyes, after the fashion of a stereopticon. A colored light slides along the arc from extreme left or right. The average subject sees the light at about a right angle from his forward line of vision, but he does not distinguish colors until the light is well toward the front. Most people cannot distinguish colors until the lights are within from 18 to 25 degrees of the center or forward point. Our tests disclosed the important fact that blue and yellow are recognized several degrees before red and _ green, which would indicate that blue and yellow are the most practical signal lights rather than the red and green now used. When a person geeaen safety demands greater care in granting licenses to drivers. We have been working out means to attain better selection between the fit and the unfit, and to render practical aid to the authorities in making this selection. To further this work we are planning still another machine in which miniature cars will approach at various speeds. The subject being tested must judge the speed of the cars approaching at right angles in order to determine which car should cross first. Through a series of wires and levers he can control the speed of his own ‘“‘car,’’ and if he judges cor- rectly, he can safely pilot his machine through the heavy traffic. This test should prove of considerable value in determining the individual’s speed of reaction and his eye-hand co- ordination. It would measure also the all-important ‘“‘emotional efficiency” Es a a tts eiaetiapanaay tia pli ahitagneee OG, ees Saar aaa ae Es, eo, a & Ba Fs -* 45 = - bod iin i wn. ths an oe ah eek ak ee

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POPULAR SCIENCE MONTHLY 69 Easily adjusted canvas covers have been devised to protect auto tires from the heat of the summer sun. The covers are attached by means of resilient metal clips that are en- gaged so as to leave air space A new radiator shutter that can be opened or closed by adjusting a rod extending to the dashboard of the car consists of an alu- minum plate reinforced by two cross strips. The plate is at- tached to the back of the radia- tor frame on the inside of the hood by two hinges at bottom The Ford emergency hand brake is easy to reach and manipu- late when equipped with this extension handle. Pull- ing the handle works the re- lease ratchet oo Seana RS phir Aen UNA EBS Oa This combined tire and toolcase, carnp table, and lunch kit is designed especially for the motor- camper. The tire hangs on a rack inside the water- tight metal container A portable refrigerator that can be attached to the runningboard, has a center container that will hold 12 pounds of ice, a large food compartment, and a_=e special rack for bottles, jars, and cans * ROH, Spare electric-light bulbs for the car are carried safely in this metal box. Steel Springs and a locking device hold them safely in the box Unsightly bent fins at the front of the radiator can be straightened easily and quickly, it is claimed, by inserting the three teeth of this simple tool, and bend- At the right is an ing the damaged fins 3 Increased engine outside view of a new front-wheel brake for Ford cars, with wheel Temoved. These brakes, installed m less than two hours, are said to reduce by about 30 per cent the distances required for stopping TO WATER SUPPLY Ly» ———— — ~ WATER FLOWS a ai INTO STORAG ' INDEX FINGER ca” GE \ HELD HERE ; A small lamp on this storage-battery filler lights when the water level reaches a correct height. Pressure shuts off the flow speed and power are said to follow installation of these twin copper con- ductors set in be- tween the engine block and manifold. With the first ex- haust the copper heats almost in- stantly, and in turn heats the fuel

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70 POPULAR SCIENCE MONTHLY Solving Balloon-Tire Problems Time and Money-Saving FLAT tire is disagreeable at any time, but A a flat balloon tire certainly is worse. One driver may have the endurance to put air into the normal tire, but in pumping up a balloon tire he will have to exert himself to the utmost. The job can be robbed of much of its disagreeable element by the use of the arrangement shown in Fig. 1. Two pumps are required as well as a standard pipe-tee connection and three short lengths of pipe for the three hose ends. Usually -in. brass pipe and connections will fit the hose used on the pump. Two persons operating these pumping units in unison just about accomplish the inflation process in the time required for the inflation of an ordinary tire by one man. REPARATORY to soldering, dam- aged auto radiators of the honey- comb type may be cleaned with a wire brush (Fig. 2) such as is used for .22 caliber rifle bores. The brush is placed in the chuck of an electric drill and for work on exceptionally thick cores a portion of the ramrod may be brazed to the brush. The device will be found useful for many other purposes. HE replace- ment of re- cessed bolts is often a difficult task with the use of ordinary tools. Much time and patience can be saved by utilizing the two tools shown in Fig. 3. The first of these is for turning a cap screw with FORSCREWS FOR BOLTS ENDS OPEN Fig. 3. Extractors a slotted head. —* It is a holder and SAW OF F_-™ we driver made of TAPER FOR a length of flat BRACE or strip steel doubled over, with the ends filed to form blades. The in- herent spring of the steel grips the screw slot so that the screw can be set directly into the tapped hole and turned into place. For a hexagonal bolt, the holder tool shown is almost identical in shape, but instead of springing open, the ends are closed with a cross bolt. ar. ELECTRICIANS BX Fig. 6. Two kinks PUNCTURED balloon tire is rather difficult to handle with the ordinary tools employed for a tire of normal size. Two methods of removal and replace- ment of balloon tires are shown in Fig. 4. Since a deflated balloon tire drops the axle lower than a deflated normal tire, it is more difficult to place the jack under the axle so as to raise it the proper height above the ground. A simple ramp con- structed as shown, 4 ft. long and 8 in. high at the upper end, raises the axle until it is level. The jack then can be put underneath and the tire removed. Fig. 1. Dual pumps The usual tire spreaders are inadequate to spread the large tire when it is re- quired to insert an inside patch or roughen and cement the inside surface. Two double holders of wood, made as shown, are of assistance in holding the beads wide apart while accomplishing inside re- pairs. The long end serves as a handle for insertion, the tool being placed into the space between the beads and then twisted about to pry open the sides. KOs Afi RADIATOR ee ' oy Seite SEI WIRE BRUSH INCLINED SUPPORT i — =-3 SECTION OF 772 BRAKE is t_! WHEEL FITS AXLE SHAFT tee? RENIOVED Fig. 7. For adjusting four-wheel brakes O MAKE unnecessary the burning of my headlights when touring, to avoid overcharging the battery, I installed a rheostat between the third brush and the field of the generator (Fig. 5). This allows the field current to be regulated. The rheostat is similar to the ones used in radio work, except that it has heavier wires to withstand the field current, which is about 4 amperes. When driving in the city or in heavy traffic the resistance is all cut out so that the generator gives enough current for the frequent stops and starts. When Fig. 2. Radiator brush Ideas for the Motorist the car is used in touring, the resistance is put on so that the generator gives about 5 amperes, This applies when the battery is in charged condition; if it is run down, a maximum charge can be given by cutting out the rheostat completely. —R. W. KEITH, San José, Costa Rica. UITE frequently an autoist has to use a funnel with a flexible tube. This is not always available and a sub- stitute can be made, as in Fig. 6. A section of BX electrician’s conduit is soldered to the spout of an ordinary funnel. When a socket for use in a brace is needed and an adapter cannot be found or purchased, a substitute can be made as shown in Fig. 6. Take an or- dinary hexagonal wrench handle and cut an inch off the handle end. File and grind one end of the short piece slightly tapered so that it fits the brace; the other end will fit the recess in the regular socket. The original handle is not damaged because it is_ slightly shorter. It has been found that either a square, hexagonal, or octagonal handle will serve this purpose. HE extent of the braking action on ears with four-wheel brakes is depend- ent upon the ad- justment of all four brakes. Some form of feeler is useful for determining if the requisite clearance exists at all points around the brake drum. As it is not always possible to use a blade feeler, a serviceable tool to test concen- tricity at all points can be made of wood and sheet metal, as shown in Fig. 7. A_ gage, which fits over the axle, has a testing edge that can be moved about the entire circumference. Having made the band concentric with the axle, it is then possible to adjust the brake so that it will clear the drum at all points. To facilitate the adjustment, the usual procedure of depressing the brake pedal with the wheels off the floor is advisable. Obviously, the front and rear wheels should. be jointly jacked up, for which purpose small but substantial wooden trestles under the axles are serviceable. To hold the pedal depressed, a block or a block and jack are wedged against the pedal as illustrated. Fig. 5. Generator BEAD FORMS SCRAPING EDGE s.ot %'x6" Fig. 8. Mud scraper A MUD scraper easily fitted on cer- tain light cars that have metal runningboards may be made by cutting away for a length of about 6 in. inside the bead or rim at the edge of the runningboard to form a groove 34 in. wide (Fig. 8). Sis RRR Oty RPI ALI RE NE TO ae eet ce eee Si BS, RR ge aot a tebe Seana tees Meo eel Bae REESE pe eet ALS By ss oOwvt kw aAre ws a nm t

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ist put Tes, ged arge tely, Ss to ube. sub- . A t is nary e is be n be . or- - cut and piece race; 1 the lle is zhtly ither ronal nt of iking cars vheel yend- e ad- f all kes. 1 of iseful ining uisite exists ints orake it is rays use a rr, a tool ncen- all sheet gage, sting ; the e the then rat it usual pedal sable. vheels which ooden eable. ek or st the 1 cer- metal itting le the board ae % ' : a : ; % t P POPULAR SCIENCE MONTHLY “Home Workshop Arthur Wakeling, Editor Building Radio into Your Home By Kenneth M. Swezey ORE and more, radio is emerging | from its purely mechanical chry- salis and is being transformed into a gratifying and beautiful utility. This transformation is being accomplished by the pro- vision of artistic cabinets, by the construction of sets to fit into articles of furni- ture, and by the use of con- cealed wiring with numerous outlets throughout the house so that a loudspeaker may be plugged in wherever desired. With the coming of built- in radio, a receiving set can be incorporated in a phono- graph located in the living- room. Wires branch out from this, and, by means of convenient outlets, the housewife may enjoy a con- cert while working in the kitchen; the kiddies can listen to a bedtime story in the nursery; delightful music can be heard while the family spends a cool evening on the porch, and an orchestra may brighten an hour at the dinner-table. THE wiring of a house for radio is not as difficult a feat as might be considered at first thought. For the benefit of those who would like to install a thoroughly foolproof system without first going through disappoint- ing experiments, the following instruc- tions have been pre- pared. The amount of — continue in circulation through the set with little hindrance. The receiving set may be permanently located in any room where it is most con- venient. Many choose the living-room, and have their sets built into phono- cabinets, or graphs, music into the Dining-room, kitchen, nursery, and porch all have radio connections section of a closet. Several ingenious mechanics even have built sets into pianos. The first outlet is made at, or near, the set (Fig. 1), and wiring extends from that to the place where the next outlet is to be installed. If the house is new and not complete, the wiring may be built right in the walls. wiring needed in the average home of six, seven or eight rooms, 622 ee Sp Finished houses BEDROOMS may have the wires — =F “fished” through the walls, as an r) DINING- electrician fishes KITCHEN ste ql lighting wires. But most home work- “son porcH ers would prefer a simpler method, does not introduce any difficult circuit problems. But in an extremely large house special apparatus would be neces- Sary to balance the various lines, over- come the resistance, and clear out dis- tortion. Stretches of wire in the loudspeaker circuit seem to have little effect on the quality and volume of reception, even up to 60- and 70-ft. lengths—especially in Conjunction with regenerative sets. This may be explained by the fact that regen- eration nullifies ordinary resistance to a certain extent, and, due to the condenser effect of the parallel wires, the radio-fre- Guency waves can pass between them and WATER-P! PE GROUND AERIALS SELECTOR '\ PHONE SWITCH FOR and they may run JACK their wires in in- FIG! —TO ANTENNA USING BELL WIRE ON SIDES OF PANEL STRIPS G [ave eso ARRESTER [vie FROM ANTENNA TO VARIOUS ROOMS a conspicuous places, such as along the edge of the baseboard, behind moldings and panels, or under the edge of the car- pet, rugs, or linoleum. Dangerous currents are not carried by the wires, and, therefore, they do not have to conform to the same standards as electric-light wiring, provided they are kept away from all light and power lines. Ordinary bell or an- nunciator wire will do, although No. 18 fixture wire, which is very flexible, or twisted lamp cord is easier to handle, better insulated, and more apt to insure the perma- nence of the installation. The woodwork of a room lends itself readily to the concealment of the wires. In most instances the base- board, door stops, and other members of the trim of the room can be pried up sufficiently to poke the wires under. This may be done with a screwdriver or a chisel, padded with cloth to prevent marring the finish. A few blows with a similarly padded hammer usually will fasten the woodwork back in its original place. Suggestions for this wiring are given in Fig. 2. OR outlets, the improved shallow single-circuit jacks, mounted in the center of a rectangular brass plate similar to those used with lighting outlets, are ideal. Binding-posts, mounted on small wood, fiber or composition blocks, also will serve, but they are not so convenient. Ordinary electrical appliance outlets are excellent and reasonable in price. The loudspeaker must be supplied with a cor- responding plug and all outlets have to be identical. But here care must be used that all radio outlets are marked with some unmistakable sign, lest a loud-speaker be plugged into an electrical socket by FIG.3: mistake, with dis- astrous results. One way to ac- complish this is to use polarity plugs, FIXTURE WIRE OR LAMP. CORD BEHIND NAY 4 DOOR OR WINDOW TRIM FIG.2 GROUND WIRE TO VARIOUS ROOMS How connections are made to various loudspeaker outlets (Figs. and wiring scheme when a portable set with a built-in loudspeaker is used re | yeye: PLUGS IN ROOMS if the regular house plugs are of the common kind, or vice versa. An- other use of polar- ity is indicated in Fig. 3, where a (Continued on page 92) CR: TOANTENNA TERMINAL TO GROUND TERMINAL OF RECEIVING SET 1 and 2),

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72 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Constructing Kites that Look like Planes OR many men, kite-flying never loses its fascination, and among boys it is a universal sport. For that reason, POPULAR SCIENCE MONTHLY asked Mr. Miller, the foremost kite authority in the United States, to pre- pare two articles on his latest kite de- siéns. This is the second article, the first having been published last month. ways. A plain kite similar to the tailless can have the outline of an airplane, as in Fig. 1, or one may be con- structed along the lines of areal plane. The model illustrated in the accompany- ing photographs is a biplane. A mono- plane is simple in comparison, but is not used much these days. The framework of the plain kite con- sists of a spine and four cross sticks of the dimensions shown at A, Fig. 1. Strings are run from the end of the first to the end of the fourth stick on each side. These strings should be the same length and drawn fairly tight; they deter- mine the length of the second and third cross sticks. - The ends of the second and third sticks should be secured with the side strings. The cross sticks must be parallel. Strong thin wrapping paper is good for covering the two planes. A keel can be added to the under side to give poise. This requires two sticks, a short one at the rear end, projecting straight out from the spine, and a long stick that forms the outer edge of the keel (B and C, Fig. 1). The keel is covered with paper on both sides. The post or back stick on this model may be about 9 in., and the outer end should have guy A vay kites can be made in two a _ ia -0 | \V ys UMM PAPER WH COVERING \ii}!)/// iH] HRA Fig. 1. A kite of the tailless variety, which resembles an airplane when flown high wires running to both ends of the fourth cross stick. The frame must be light. The spine, the heaviest stick, is about 5/16 in. thick and 1% in. wide, while the cross pieces should not exceed 14 by ?g in. The keel stick need not be more than 14 in. square. An upward bend to the ends of the planes (D) helps to give stability. This Fig. 3. Framework without planes and tail By Charles M. Miller can be accomplished by bending each cross stick like the bow of a tailless kite. The bridle should be attached at four points, one on each side of the spine on the first cross stick and one on each side of the spine on the fourth cross stick. The points of attachment should be about halfway from spine to the end of cross sticks (C, Fig. 1). The lower bridle strings should be? about half as long Fig. 4. Complete framework again as the upper; that is, if the upper ones are 2 ft., the lower ones should be 3 ft. The kite line is attached where all four come together. The exact length or proportions cannot be fixed except by trial, but if the kite stands too straight up, and does not rise high in the air, the kite line should be raised on the bridle; if the kite goes up so as to ride too far overhead, lower the line on the bridle a little. If the kite must have a tail—it is hoped it will not—streamers should be used in- stead of the ordinary old style tail of string and rolled up papers. Is it understood that the covering for the planes are put on the under side of all kites? In the present case the cover will be on the same side as the keel. A paper windmill can be attached to the front end of the spine to represent the propeller. GREATER but far more interesting problem is the making of a kite in the form of a model airplane. The frame- work of the fuselage, which is the central body- of the airplane, is made up of four spruce sticks 3/16 by 3/16 by 48 in.; two front uprights 14 by 14 by 14 in. and two rear uprights 14 by 14 by 8 or 9 in. (E and Fo Pig. 2). The strain on the framework should be shifted from the fuselage to the plane frames, where the lifting power is cen- tered; the fuselage frame then becomes a mere form for effect and practically is sus- pended from the planes. This being the case, the framework of the fuselage can be very light. A little bracing will prevent a collapse. The first uprights, which support the upper plane, extend 414 in. above the fuselage frame; the second pair extend 314 in. above. This gives a tilt to the planes. The fuselage frame is 514 in. high at the first pair of posts, while at the sec- ond pair it is only 414 in. The two side frames of the fuselage are made first and then are connected by means of crosg pieces 514 in. long (F). The plane frames, being wider than the distance between the first and second pairs of upright posts, must necessarily overhang the space in- closed by the posts. Four pieces running from front to back support the plane frames; these are 4 by 14 by 12 in. After the sticks are securely lashed together, they should re. ceive a good coat “of shellac at the joints. Now two pieces (G, Fig. 2) should be made of 14-in, pine, the one for the front end 314 in. square, anda similar but smaller one, 2 in. square, for the rear. One-quarter-inch notches are cut in each corner, as shown. The long fuselage members are sprung together and tacked to the blocks with 1%-in. No. 20 brads, but to further secure the corners, it is best to wrap about five windings of strong linen thread around all four sticks, just back of the front block and just in front of the back one. Shellac where the windings come in contact with the sticks. The fuselage framework now should be complete, as shown in Fig. 3. The frames for each plane consist of two pieces 4 by 1% by 48 in., and two cross pieces 14 by 14 by 12 in. The cross pieces extend 14 in. beyond the long pieces so as to leave room for good lashing; in like manner the ends of the long pieces extend beyond the cross pieces. To give support between planes, short posts 44 by 14 by7 in., four in number, are placed, one at each corner. The posts can be a little long T © Fig. &. The finished kite ae s + aia Yo x Vox a” Fig. 2. First steps in building a model air- plane kite, and propeller and hub details and be lashed to the side, or they may stand in between, held in place by a No. 20 brad. The brad may pull out, so 4 piece of linen thread or fine wire should be wound about the two vertical corners, to prevent spreading. Before the four upright posts at the corners are put in, the upper plane should (Continued on page 109) oe er ee casa: ey. Seb ke eaasek : F i _ —- eee ae ee ae eae ae Om le hue

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CS 0 side t and CTOss ames, 2n the Posts, ce in- nning plane \. sticks rely ether, d re- 1 coat it the w two Fig. be 14-in, ne for id 3% and a e, for Ss are > long or and lo. 20 ers, it igs of sticks, ust in re the sticks. Id be of two » CTOSS pieces 3 SO as n like oxtend ipport 4 by7 t each 2 long air- tails y may a No. tr, so a yuld be ers, to at the should pibeian Le avn ae Ate ¥ scahegaitanergeger ae igs pes 2 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Dilapidated Table Becomes Fine Chest By Gladstone Califf Superintendent of Schools, Richland,Ia. T chest illustrated was made from the boards of a discarded walnut dining-room table and lined with cedar. To make and the outer edge of each has a 1¥-in. bevel. The mitered edges are made with a plane and tested with a T-bevel. The chest is then lined with 14-in. thick red cedar. In upholstering the top, the first cover- one like it, lay out and make ing of cloth is tacked at one end and a short distance along each side. The pad- ding of flax straw or other filling then is pushed under with a short blunt stick. The padding should be level on top and sloping at the side and ends. After this part is filled, tack farther on each side and put in more the sides and ends of the if ”\ piel — = = padding, continuing until dimensions shown in the | UNDER SIDE OF helteeed Sd. ere rome finished. The end is accompanying drawing. It | ll ARRANGEMENT OF duced below stretched tight and tacked. ig necessary that they } ae ee , The top covering of should be perfectly square i leather or imitation leather or the box will not be square ay: bi i next is tacked around suffi- when assembled. The bot- .===s====s>====> == + ciently to hold it in place tom, which is cypress, is [i) | —*F-fifl].. , | until the gimp or tape is fitted in from underneath. 4) Ms eever™| the ||? oe a fastened on with furniture The top can be walnut, i} | YBever 1 x nails or upholsterer’s or although if it is to be up- ; $F} cena gimp tacks. The nails or holstered, a soft wood will * Avs | o tacks should be spaced serve the purpose. J bei * regularly and evenly all the The sides and ends are joined with plain butt joints, glued and nailed with finishing nails. A large steel square is used for testing the squareness of the assembly. The top and bottom trim is mitered around the chest after one edge of each is planed to a %4-in. bevel. The lid trim is not beveled. All these trimming pieces are nailed and glued. The corner protectors are mitered to fit Front and way around. end views of the chest and under side of lid, with di- mensions, are shown above. The entire chest is lined with 14 -in. red cedar and the top is up- The wood should be scraped to remove all plane marks and sandpapered smooth. If a natural finish is desired, fill the wood with natural paste filler, apply two or three coats of white shellac, rub smooth and fin- ish with wax. Thewoodmay holstered e be varnished if preferred. Child’s Bench Changes Quickly to Table to ten years of age would be de- lighted to receive a combination table and chair like that illustrated. It is made of %%-in. pine stock glued and screwed together. The feet are sawed from stock with the grain running lengthwise. The sides, which are made sep- arately, are Nt te any little girl of from four the cleats and must be threaded a short distance on each end for nuts to keep it in position. If a piece of wood were fastened to the back, barn-door hinges might be substi- tuted satisfactorily for the steel rod, although the latter gives perfect satis- faction. A decorative piece of 3-in. wood is attached with finishing nails just below the seat. A small rubber-headed nail fastened to the feet with glue and with wood screws inserted from the inside. The seat is the same width as the sides, to which it is held by wooden brack- ets beneath and by countersunk wood screws driven in from the outside. These holes must be con- cealed by small wooden plugs or by putty. The top is made by gluing up Several knot-free boards and, when dry, sawing out a circle. On the under side of the top two driven into the front end of each arm of the chair deadens the noise when the top is lowered. A hook and eye should be inserted in one of the sides of the chair and in the top so that when the latter is held back, it cleats or battens are used to give additional strength to the glued Joints. The cleats, which are, of course, parallel, should be fas- tened so as to be just outside the sides of the chair when the top is lowered. With the top in the desired position on the chair, a 3-in. hole is bored through each of the back corners of the sides and through the cleat. Through these holes a steel rod is run as a fulcrum on Which to swing the top. The rod should be slightly longer than the distance across The combination bench and table and diagram, showing suitable di- mensions can be hooked in place. This is to obviate any danger of the top’s being knocked over accidentally on the child’s head. Before fastening the top permanently in position, the wooden parts should be given three coats of red or other col- ored enamel. A glossy finish is imper- vious to smudgy fingers.—R. L. SIMONS. Supports for Growing Plants UITABLE supports for thin stemmed plants that grow to a height of 18 in. or more can be made of light stakes and strong but readily bendable wire. An adjustable plant support made from a piece of wire 2 ft. long or less and a single stake is illustrated in Fig. 1. A three-stake compartment support (Fig. 2) is better for plants such as peonies, which send up frail stems with heavy foliage at the top. - ) F tJ Vigs supporting very tall plants, such as cosmos, which generally are placed in a line or screen formation, is indicated in Fig. 3. At each end of the line a stake not less than 2 by 2 in. and 6 ft. high is driven deeply into the ground. Half- i way up, a cross- “ piece is nailed; this Types of support should be as long as the line of plants will be wide. At the top a shorter cross piece is nailed. The cross pieces are connected by four light, straight wires. When the plants are well above the lower wires, either wire or cord should be crisscrossed from wire to wire, making a number of compartments, and this is repeated when the plants have grown above the upper wires. Stakes and wire should be painted or stained green or brown so that they will be relatively inconspicuous.— WILLIAM F. SANDMAN, Indianapolis, Ind. A method of 1G2

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74 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY “Wasslers” for Water Golf Made at Home AMEY, free-for-all water golf can € be played with the homemade outfit illustrated. ‘‘Greens’’ can be moored almost anywhere, and a two- hole course can be played back and forth even on a pond. The waggler, fitted with air tubes under the seat, can be shifted about with pedal-fins, which have power enough to propel slowly. The combined _ paddle and drive, loft, and putt either a light, 2-in. waterproofed wooden ball, a tennis ball, or a rubber ball with a spongy core, about 21%-in. size. The materials needed for one outfit are. Pine board, % by 12 in. by 10 ft. Ash paddle-board, 1 by 6 by 36 in. Studding, 2 by 2 by 40 in. Studding, 2 by 3 by 14 in. 2 corner braces, 3 in. 3 corner braces. 4 in. § 1 bolt, 4% by 5% in. ress. At 2 door springs, 4% by 16 in. right: Details 2 large furniture glides (casters) of the pedal- 1 yd. drilling, 30 in. wide ‘ driven “wag- 2 pieces galvanized sheet steel, each 4 by 14 in. gler,’’ the 2 lengths i4-in. gaspipe, each 7 in. long, fitted he OE tte with caps 2 doz. screws, No. 6, 34 in.; 2 doz. screws, No. club and 10, 14 in.; 2 base-knobs; 4% doz. screw-eyes, paddle, and 114 in.; 1 doz. 34-in. copper rivets and burrs; one of the 6 nuts, 4 in.; 2laths; 2 discardedinnertubes, —_“‘holes”’ patched. - Each hole requires: -_ good barrel-head Studding-rib, 2 by 4 by 18 in. long 3¢-in. gaspipe, 7 in. long, and one nut 2 pie-plates, 10-in., heavy tin or agateware 1 coilspring, % by 5 in. 1% ft. jack-chain, 5%-in. link; large spool; cotter- pins Each half of the waggler’s keel is cut from a 12-in. board, the upper part being 34 in. long. The seat-board is 24 in. long and 8 in. wide at the cantle. Pommel and cantle are shaped from 2 by 3’s. club will on Sted ge Above: A game of water golf in prog with side strips, be 15 in. long at the By Roland B. Cutler Slit 15 in. of the drilling to center under the board, at the rear, and tack around a back-board 3 in. wide, as indicated. Set two 4-in. corner braces to support the seat, 9 in. from the rear end of the keel board. Then assemble these parts. Each doubled inner tube extends under the seat, to be doubled again at the j rear. Tie the tubes Ae at the head. Secure cE. the drill casing with a lath at each side,

and fold to inclose the head. Each side of a pedal is 9 in. long and SPINDL’ CHAIN 3 in. high, with a heel-block 5 by 21% in. wide nailed between. Over this block, locate the pipe-axle 314 in. from the heel end. Shape the sides as shown, and at- tach a toe-strip 14 by 2 by 8 in. long. Set a 3-in. corner brace at the heel, and rivet the fin under the strip. Complete the heel with leather fastened securely against backward thrust. Let the lower keel-board, when joined Graceful Wrought-Iron Reading-Lamp for the Amateur Craftsman

By H. T. Shrum State Normal School, Oshkosh, Wis. RTISTIC wrought-iron work A has been revived to a great extent during the last few years and many decorative pieces are being used in the home. This is evident from the number of iron candlesticks, plant and aquarium stands and reading lamps to be seen in the art and gift shops. The accompanying photograph and drawing offer a suggestion that might be used as the basis for the design of a reading-lamp, or the dimensions may be followed and an exact copy of the original lamp made by any craftsman who has

[ray 2 15°) "x2"

access to a forge. Care must be taken to make the design well proportioned in order that the finished product may be pleasing to the eye and not too

Dimensions and details of an un- usually attractive lampstand constructed of wrought iron

bottom. Cut a 2 by 2 in. pedal shank, 20 in. long, and locate the axle 11% in, from an end. Set a gliding caster 8 jn, from this end, to slide over the keel, Pivot the shanks to the keel 10 in. below the center of the seat. To block the shank, set a spool-knob about 15 in, below the seat. Run the shank spring as indicated. ) Any thick barrel-head makes a ‘“‘green” for a hole. Cleat the head to allow for a center cut-out of 814-in. diameter, and space for the 2-by-4 rib. This rib is cut down 2 in. below the hole, with a 5<-in. hole centered for the gaspipe spindle, which is turned in like a screw. Cut around the bottom of a pie-plate, allowing a 14-in. projection, and center it bottom up around the = spindle, Nail down the rim, The upper plate, with a bottom hole centered for the spring extension, sets on the spindle nut, which aust be locked wuver jammed threaas, flush, or above the pipe end. Pin one end of the spring in a large spool, as indicated, and to the other end hook jack-chain, to be pinned under the rib. Adjust the spindle to allow space between plates of about 4 in. less than the diameter of the ball. The club-paddle blade is about 12 in. long and 3¢ in. thick. The three club parts are alike, each %-in. stock, 4 in. high, with a 2%-in. sole, and 1-in. top. Fit a 4-in. corner brace to the middle part; then attach each side with three long screws and spacing nuts. Pad between the blade and attachment with a rubber cut T shape. Keep the spindle spring well greased, and paint and oil all the equipment.

heavy in any one part. The method of joining the parts must be con- sidered carefully. Where rivets are

UCOUPLING—s5 Sate" j used—and I think that this method TS f of fastening is the best for this type . we 4"aIn3 of work—there must be considera- sPIPE TAP Fe tion for drilling holes, for heading 5" DIAM: eats the rivets, and backing up the rivet sie or L- 3’ GAS PIPE heads. i n. Fa If round-headed rivets are used, | ALL ENDS FINISHED ; the shape of the head may be re- | THIS WAY 2 tained and the riveting done very | $74" COUPLING —+ + easily by making a special tool to : fit in the hardy hole of the anvil. ) octadhainiis. This is merely a short piece of *4- or %in. iron bent to a right angle to fit in the hardy hole and project an oa inch or two beyond the edge of the | anvil, where it bears a dent the size of the rivet head.

STAGGER RIVETS LIKE THIS _

Care also must be taken when laying out the rivet holes to have them at the points of contact or the (Continued on page 98)

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ne Shank, 1) in, er 8 in, ie keel, . below ck the 15 in. | Spring “‘oreen” low for ter, and b is cut -in. hole which is ie-plate, 1 center spindle, the rim, r_ plate, tom hole for the tension, spindJe- ii AUst da uver hreaas, 00ve the Pin one e spring spool, as and to nd hook , to be ider the ust the > allow et ween bout \% ball. it, 12 in, ree club k, 4 in. -in. top. dle part; ree long ween the er cut T greased, lan » method be con- ivets are ; method this type ynsidera- heading the rivet ire used, y be re- ne very 1 tool to ve anvil. ce of %4- ht angle roject an ze of the , the size on when to have ct or the 98) POPULAR SCIENCE MONTHLY Wuuson's Wouo Drt 25c¢c Book on Wood mee ae hie Our book gives complete instructions for finishing all wood—hard or soft—old or new. Tells how inexpensive soft woods may be finished so they are as beautiful and artistic as hard wood. Explains just what materials to use and how to apply them. This book is the work of experts—illustrated in color—gives covering capacities— includes color charts, etc. JOHNSON’S (Penetrating) Johnson’s Wood Dye is very easy to apply. It dries in four hours and will not rub off or smudge—penetrates deeply, bringing out the beauty of the grain. Johnson’s Wood Dye is made in 17 popular shades as follows: No. 128 Light Mahogany No. 125 Mission Oak No. 129 Dark Mahogany No. 130 Weathered Oak No. 127 BrownMahogany No. 110 Bog Oak No. 329 Red Mahogany No. 120 Fumed Oak No. 172 Flemish Oak No. 123 Dark Oak No. 178 Brown Flemish No. 126 Light Oak No. 131 Walnut No. 124 Golden Oak No. 140 Early English No. 160 Brown Oak No. 180 Gray All shades may be easily lightened, darkened or inter- mixed. Full directions on every label. Select the shade of Dye you want from the list above and order it from your dealer by name and number. S. C. JOHNSON & SON, Racine, Wis., U. S. A. “The Wood Finishing Authorities’’ Use coupon below fora FREE copy. WOOD DYE Johnson’s Wood Dye is a dye in every sense of the word. It contains no finish whatsoever. Like most first class products it answers one purpose only—it dyes the wood —the finish must be applied over it. We recommend Johnson’s Varnishes or Johnson’s Polishing Wax. Stores displaying the Johnson Service Department Sign carry a complete stock of Johnson’s Artistic Wood Finishes and will be glad to show you finished wood panels—and answer questions on how to finish wood the proper way. 8 S.C. JOHNSON & SON, Dept. P.S.M. 8, RACINE, WIS. f q 5a “The Wood Finishing Authorities’ ¥ 2 (Canadian Factory—Branttord) ' | Please send me free your Instruction Book on Home iy Beautifying and Wood Finishing. I enclose 10c to - cover postage and wrapping. q | i i BEY DEALER IS... 20.00 ccccccccccdsdeeceieicevecas } g My Name...........cccccccccccccccccsssccccces a | GE ee a Te i g é Ciky arid SiMe on ogo ic ciiecs eevee cencsessemeecves - Wes come coms es es eee ee

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POPULAR SCIENCE MONTHLY Better Shop Method How Expert Mechanics Save Time and Labor J ai (al enon How to Make the Most of Planer and Shaper By H. L. Wheeler Machine-Shop Foreman i OOLS are tools,’’ remarked Old Bill to one of the machine hands, ‘“‘and it doesn’t make so much difference as you think whether they go in a lathe or planer or milling machine. Cutting metal is the same problem, no matter where you run up against it.” Old Bill, wise in machine-shop methods from many years of hard experience and shrewd observation, is a_ stickler for watching what he calls the business end of any machine tool—the cutting tool itself. To do its work properly, the tool must conform to certain well established principles of form, and these principles apply whenever metal is to be cut. Shaper and planer tools are very similar to lathe tools: in fact, a tool made for one may be adapted readily to any of the three, as the cutting action of these machines is practically the same. The only actual difference is that lathe tools as a rule require a little more clearance _— LIP ANGLE BLUNT POINTED TT] OW HEAVY = LIGHT CUTS CUTS BACK SLOPE FORMS OF PLANER \ ROUGHING TOOLS ‘ Fig. 1. Typical : planer tools and a a goose-neck tool for G00SE*NECK TOOL the long, heavy cuts than planer and shaper tools. The angle for planing tools is from 3 to 4 degrees and that for lathe tools from 5 to 8 degrees (Fig. 1). The clearance angle will vary for the different metals and the kind of cut being taken; in any case it should be only enough to allow the tools to cut freely and avoid digging into the work. Too much rake will weaken the cutting edge and give it a Using a shaper to finish a circular surface on work that will not swing on centers in the: head or rail. This is eliminated with the goose-neck, as it springs away from the work and will not cause any damage by undercutting. The cutting point of this tool should be on a line with the rear side of the shank or even farther back. In the larger shops, machine tools seldom are expected to perform unusual tasks or do stunts. Small jobbing shops with only a few machines often are called "upon to perform almost impossible jobs or jobs that are not strictly within the range of their equipment. A few illustrations will give some idea of what may be accomplished on a small planer. In Fig. 2 is shown how a large casting was planed on a small planer. The casting could not be fastened on the platen and passed under the rail or between the housings, so it was set up on the floor alongside the machine. The cross rail was removed and set up on the front end of the platen with angle plates and blocking. This allowed it to project far enough to one side to reach over the area to be planed. When the casting was located and leveled and the cross rail fastened in the desired position, the stroke was set and the tool was fed across the work by hand. The familiar magnetic chuck, used extensively on grinding machines, is a time-saving fixture to use on planers for holding flat parallel strips and similar work. Try planing a strip of steel or iron 3 or 4 ft. long, 2 in. wide and \ in. thick by holding it in the old fashioned way; 9 pieces out of 10 will be neither straight nor parallel. Now try this same job with a magnetic chuck and note the difference in time saved in setting up and in the quality of the work. Often the time saved in setting up various jobs by the old method of bolts, straps, pins, hold downs, and the like will more than pay for one of these chucks. They are made CROSSRAIL CFE? MOUNTED ON PLATEN |! Fig. 2. Method of planing a casting too large to be handled on the machine’s platen in various lengths. For extra long work, two chucks may tendency to dig into the work, The slope angle should be decreased as the depth of cut and the feed are increased. The reason for this is that heavy cuts induce excessive pressure on the tool, therefore it is evident that a blunt tool with a stiff cutting edge is better able to resist the in- creased pressure. The goose-neck tool shown in Fig. 1 gives better results on long, heavy cuts than a straight tool. A_ straight planer tool has a tendency to dig into the work and chatter Old Bill Says— slipping or lagging on the job. shop work? The man who first said ‘‘Make haste slowly’’ must have been a machinist; if he wasn’t, he ought to have been, because it certainly holds good in the shop. Don’t take it for granted that a tap will stay sharp forever. It’s like any other tool, and if you grind it occasionally, you'll do better work and won't be so apt to break it. Fancy frills on machine work went out of style ages ago, unless a customer wants to pay for them, and that’s another story. HENEVER you feel like saying, “I don’t know how,” stop and think if it wouldn’t be better to make it, “I'd like to try!” Taking a couple of inches out of the belt sometimes helps to speed up a machine that is You never put on your collar before your shirt; why try to do a thing backward in your be used end to end. It will be much cheaper to purchase one of these chucks than to attempt to make one. In addition, with their use the planer may be converted readily into a grinder simply by mounting an emery wheel on the cross rail. Another useful attachment for the planer is a milling head, which practically con- verts the planer into a milling machine. In conjunction with this a good set of indexing planer centers are valuable. These attachments may be purchased or built in the when there is any looseness (Continued on page 82) iy = 4 id = q a & sah Se Ties Asa Sia te

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POPULAR SCIENCE MONTHLY et up The yn the plates roject er the iz Was Ss rail , the re : Cher loss i Casse/; "“® used @ - cececa. A ,isa & ~ ors = a oe zi AIL S ” or iron ea cm i tarrett *s! | way; fe raight — - i “Boy—you certainly come well recommended.” gn i “Yes— that’s what the foreman said when he looked over 7 2 my kit this morning. And right away he wanted to know noe 7 how soon I could come to work.” / Maae ie AS , Planer—Shaper—Lathe—Layout HEY) B ; . te _ Whatever your work you will do it better with | 4 Starrett’s—the precision tools preferred by two a generations of crack machinists. Starrett Tools i are practical—first last and foremost they’re 4 made to make it easier for you to do accurate a work. Be sure to get the new Starrett Catalog showing the complete line including the new tools rst added since our last catalog was published. Write us for free copy if your hardware store can’t supply you. Ask for No. 23 W. too iten r extra THE ie S. STARRETT CO. ‘Ss may The World's Greatest Toolmakers will be Manufacturers of Hacksaws Unexcelled wehew ATHOL, MASS 3 than , . ne. In ise the verted simply r wheel G bat 4 chment milling ly con- ae milling oma 400 S \dexing luable. nay be YER aS in the Te 82)

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78 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY e | Need for Studying Better Shop Methods } * e e e ] Shown in Piston-Ring Contest ~ ; hal STONISHING in one respect were The boss had called Jim into his office way to do the job, a little present will be | rc A the letters submitted in POPULAR’ early one Monday morning to talk over yours. You see, the order is worth it.” -_ SCIENCE MONTHLY’S recent con- the production of a new style piston ring, we ov test on the machining of special interlock- which had been submitted for prices. By James Ellis wa ing piston rings—no two of the solutions “We have a chance of receiving a good Memphis, Tenn. | ce were alike. Every one of the replies varied size order,’’ he continued, “if we can a ‘up somewhat in the method suggested for handle this in a short time. The time ele- Second Prize, $5 | th making the rings. In view of the relative ment will govern the price. Now, here is D MUST have thought that I had simplicity of the problem, this variation what the ring looks like.”’ something unusual when I approached Yo was surprising. him, for he looked at me. with an | rir It will be recalled that the con- Z LOCK-JOINTED RING CLOSED air of “Why pick on me?” ta test, which was announced in the og eee anna ae But pick I did. It was a piston W May issue, was for a story giving rom wi | ring with a most peculiar joint, th the clearest information—just as a Wl MM Rn asseneninnen Something like some of the fancy | th machine-shop foreman might give get rings on the market, but not quite. | m it to a relatively green machine Only three were wanted, so we | hand—as to the simplest and could spend no money on special | of quickest way to make the special fixtures; and, as they were wanted | ne locked-joint piston ring illustrated in a hurry, there was no time to lose | st in Fig. 1. in discussing the method to use. | T That thoroughly experienced The ring was for a small air com- \E machine-shop foremen and machin- pressor, and the joint was made as if ists should differ so much on the shown at A (Fig. 4). tl steps to be taken and the tools to y et Ed looked at the blueprint and W be used is a striking commentary 4te oi ee groaned. upon the necessity for careful study a \\\\\e MERITS “How in the world am I going to h sea methods and the vital need \ IN (nec “_— for the interchange of opinion among mechanics as in the columns of the Better Shop Methods De- a step-jointed ring pare his solution with those offered Mr. partment. machining this special interlocking piston ring “Biest turn up the rings —s t The origi- ; ; ; usual way, and leave a third of the 0 nal problem was The boss copied from a blueprint a ring length of the lap on the diameter to ly STER-JOINTED RING ClosecD SUbmitted by suchas is we in Fig. 1, 3 in. in outside make the joint, and a little more so that ‘s ; TWO MILLED George A. Luers, diameter and 2°% in. inside diameter. you can return them after the joint is is i jCUTS MAKE = one of the best You see, Jim, the scheme is to have made. Finish the width to the dimension lt 1g THISJOINT. known writers on locked joints, so they put that little pro- given. Then cut a slot across the face of |" mechanical and __ jection on the inside to do the work. Ac- the ring like this (B). You can do this on rr STEPJOINTED je automotive sub- cording to the print the lock is }4 in. long. the shaper or the milling machine, which- — jects, and it is in- To make allowance for the lock you will ever you like and can get. | Fig. 2. Machining teresting to com- have to turn a ring 3 3/16 in. in diameter. | | | | by the prize-winning contestants. Luers said: “Recently we had a small air pump under construction that involved metal packing rings. Inasmuch as it was de- sired to lock the rings in the cylinders be- all reasonable. 0O=S>- ere FL Fig. 1. The problem is to explain the method of “After we turn the ring up, we had better saw it apart with a hacksaw. This we will call our second operation (Fig. 3). The third operation I think we had better do on the small bench will turn the ring make that thing?” he asked. “Not so hard to do, Ed,” I re- plied. ‘How does this scheme strike you? “The next thing you will have to do on the milling machine, though. You will have to use a rather small cutter, and you can’t use an end mill very well, so I would suggest that you use a Woodruff keyway cutter. Scribe a line across the diameter of the ring at right angles to the slot you have just made. This line is to help locate the ring on the milling-machine LINE A DRESS THIS SURFACE SO cause of a port, a special lock joint of the lathe, using the | type sketched in Fig. 1 was decided upon. milling attach- ieee? When the drawing reached the machine = ment. Of course, Oe | shop, the problem had to be explained OUTS! DE our ring will be — 2a paella thoroughly to the foreman before he Fig. 3. Mr. Coakley’s fastened flat to the “ — i | would acknowledge that the design was at method (first prize) fixture. Now we | “An ordinary step-joint piston ring is illustrated in Fig. 2. When the ring is closed, the machining is not obvious, but when the ring is expanded, it will be seen that a slot at the top and bottom severs the ring and makes the lap joint. In the special lock joint the same procedure ap- plies. After the slots are made, the ring is milled off on the outside and end mill cuts are made on the two areas inside in the wake of the interlocking ends.” The prize-winning letters are as follows: By Frank N. Coakley Buffalo, N. Y. First Prize, $10 i en we have a job this morning that I should like you to take hold of and machine.” over and make it look like this,’’ and he drew a dotted line to show the fourth operation. “You will have to make a little rig to hold the ring, so that you can rotate it the length of the lap, so that the lines will be curved alike. Now we can go to our fifth and sixth operation, which I think we had better do on that little bench filing ma- chine of ours. That will give us a ring looking like this from the top and some- thing like this from the outside,’’ and he drew thesecondand third sketches in Fig. 3. ‘‘Now our ring is ready to lap together. It might be necessary, Jim, for you to smooth up the inside and outside of the ring after you get through with the last two operations. Now, let’s see what we can do. Bring in a couple of rings when you finish them and if you find a shorter RIGHT E ANGLE THAT THE JOINT FITS TO SLOT B FIRST OPERATION ed D FITTING ee TURNED TO [)\ FINISHED C CLEARANCE MILLED SECTION CASTING HELD IN CHUCK Fig. 4. Steps suggested by Mr. Ellis, winner of the second prize E RETURNING table. Clamp the ring right on the table, close to the edge where you can reach it with the Woodruff cutter. Set the line just made parallel with the edge of the table. Start the cut in the slot already (Continued on page 79)

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1s ill be | had ached th an viston joint, fancy quite, O we pecial anted 0 lose ) use, com- de as t and ing to I re- *heme n the of the er to ) that int is 2nsion ace of his on vhich- do on u will d you would >yway meter yt you help chine ci ROUND —2 CE SO ITS — NED TO ISHED \ SCREW NING table, ach it > line f the ready | Need for Studying Shop Methods | | (Continued from page 78) | made, and cut just even with the edge of ‘that slot. The depth should be exactly ‘half the width of the ring. Use the mi- | crometer dial to get the depth. | “When one side is milled, turn the ring over and do the other side in the same way. You wili have to transfer your | center line to the other side in order to set ‘up for the second in correct relation with | the first. “The ring will now look like this (C). You might do some more milling on this ‘ring, but I think you will do better by taking it to a vise and filing the rest of the way. Saw the ring in two in the center of | the first slot, and file the points so that | they will fit up into the curve left by the ‘milling cutter. | “You will probably have to file the ends | of the points in the direction of the thick- | ness, too, for you have been making | straight cuts, and the ring is a circle (D). | This is the most particular part of the job, ‘| Ed, and I want you to be very careful, for if the man who designed this ever sees it, | the first thing he will do will be to see how | well that part fits. “When you get the joint made, make a holder something like this (HZ) to re-turn | the rings. Chuck a piece of cast iron | large enough to true up to the finished | size of the ring, and turn it back to that | size. Face off the end square and drill and | tapa hole for a cap screw. Find a washer, | or make one, so that you can clamp the | ring to the face of this casting while it is | stillin the lathe. The finished part, which | is the same size as the ring you are going | to turn, will help you to locate the ring. | Turn off the diameter, and the job is | done.” Ed smiled. “That doesn’t sound so hard. how hard it really is.” | Ed made the rings. \ — | While the solution of Mr. Ellis is open | to the criticism that he has neglected the | tun of the milling cutter and that he might | better have cut thering and expanded it be- fore milling the lip clearance, he has, never- theless, covered the necessary machining methods and done it with a clearness and Precision that are to be commended highly. Other readers who are entitled to honor- able mention for their contributions are: James Oswald, Brooklyn, N. Y. John Maghirelli, New York. T’ll see Rack Keeps Washers Sorted | \ HEN you are in a hur- Ty, it is an exas- perating job to find the right | washer in a boxful | of assorted sizes. | The wooden rack | Or tray illustrated enables you to pick out | the proper sized washer immediately and _ to tell at a glance whether your stock is | Setting low. A similar tray might be used for different sizes of nuts.—F. 8. Root, | Fall River, Mass. ——__ BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY look. ( yy) / Abundant lather Quick action Await you in Palmolive Shaving Cream GENTLEMEN: brought to millions in Palmolive Shaving Cream. of’ them were satisfied, perhaps. by famous experts. In the short time since then this soap has become the Shaving Cream sensation. It has built up a new idea of what shaving cream can do. bubbles support the hairs for cutting. We did it to please men like you. coupon. To add the ; luxury, we have created Palmolive After Shaving Talc—especially for men. Doesn't show. and fresh, and gives that well-groomed Lasting lather Fine after- effects Five New Joys By V. K. Cassady, Chief Chemist If a Shaving Cream excelled all others in one way you'd be delighted. Let us multiply that delight by five. Let us show you five new joys we have This offers you a Ten-Shave Tube to try. A very unique creation Three years ago most men were wedded to some other soap or cream. Most Then came Palmolive Shaving Cream, made The final result of 60 years of soap study. A test was offered which countless men accepted. The users were amazed. The results men like Palmolive Shaving Cream multiplies itself in lather 250 times. It softens the beard in one minute. It maintains its creamy fullness for ten minutes on the face. Its extra strong The palm and olive oil blend makes after-effects delightful. We made up 130 formulas in seeking to perfect it. Now judge the result for yourself. Clip this Mail it at your leisure for a Ten-Shave Tube. THE PALMOLIVE COMPANY (Del. Corp.), 360 N. Michigan Ave., Chicago, Ill. PALMOLIVE SHAVING CREAM Try it as a courtesy to us. final touch to shaving ves the skin smooth 2372A 10 A FREE and a can of Palmolive After Shaving Talc Simply insert your name and address and mail to Address for residents of Wisconsin, The Palmolive Company, (Wis. Corp.), Milwaukee, Jis., Dept. B-845. Address for residents other than Wisconsin, The Palmolive Company (Del. Corp.), 360 North Michigan Avenue, Chicago, Ill., Dept. B-845.

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

Shop Hints that Save Time and Effort depends mainly upon _ practice. What a real expert can do with a file is little short of astonishing. There are, however, a few simple directions in regard to filing that no one should over- look. One of these is that a hand file should be used only as a one-way tool. The teeth are shaped to cut on the for- ward stroke only. Filing on the return will ruin the tool. Use a machine file and PB ecoen is an art in which mastery never a hand file in a filing machine, as the pressure is applied both ways. In filing shafting or other round work in a lathe, keep oil on the work to prevent clogging and to avoid making ridges and In any kind score marks on the work. of filing keep enough pressure on the work, otherwise the surface will be- come glazed and the file points dull. Remember that the more commonly used files are thickest in the middle to allow for the rocking that in-

' SQUARE STUD’ Fig. 2. Wrench for awkward work

PIN OR RAM variably occurs PIECE. TO BE while working > (Fig. 1). For this reason fewer teeth are in con- tact with the work than would be the case if the file were perfect- ly flat, and the bite of the teeth also is greater. Using a file as a hammer or throwing it into the toolchest among other tools will soon make it worth- less for fine work. It should be given the care accorded to edge tools. Large files should never be fitted to their handles by boring a hole in the wood and forcing in the tine. The pressure will split the handle sooner or later. Bore a hole the size of the small end and then burn out the rest with the tine heated to a low red. Keep wet waste around the body of the file so as not to draw the temper. a stubborn stud SCREW Fig. 7. for LOSE quarters in which it is almost impossible to use any of the standard wrenches for removing bolts and nuts, are often encountered. For such contingencies it is useful to have a set of special wrenches. These can be made out of the ordinary wrenches simply by cutting them down, as shown in Fig. 2, and riveting in a short square stud solid enough to withstand the pull of another wrench. A set of these will shorten repair jobs and make unnecessary the use of chisels and punches to turn inaccessible nuts. HANDY pilot that will aid in start- ing spring shackle bolts into their seats is shown in Fig. 3, Made from the

CUTTER Scraper grooves end of an old bolt, it is tapped to conform to the shackle-bolt thread and is ground to a taper. The outside diameter should be the same as that of the shackle bolt. When the pilot is screwed on in place of the nut, the bolt can be driven in with ease. STUDS or pins that defy removal by usual methods sometimes can be driven out of their seats by hydraulic pressure, as shown in Fig. 4. The piece is cut off near the surface of the piece in which it is embedded. A hole is then drilled to the bottom and reamed so that

The table top is built on the wheel, with its center resting on the hub. A square box, the four corners of which come flush with the tire, serve as the main support for the top, which is round and extends 2 in. beyond the tire. O SAVE time in the use of C clamps, a Washington, D. C., shop substi- tutes for the usual square-headed set- screw, a clamp screw made as _ shown in Fig. 6. Round bar steel stock is used. One end is bent to form a handle and the other to fit the clamp. The ad. vantage lies in doing away with the need for a wrench to tighten the clamp, _* REMOV- ING carbon from piston-ring grooves, a_ tool such as is shown in Fig. 7 comes

PLITETTIISILL NSS wWeneeaaay diesel > in handy and - < Oe, saves consider- Foie able time and wa effort. An ordi- Fig. 3. Pilot nary piston-ring for spring bolt compressing tool or a strip of cold

rolled steel slight- Filing ly wider than the SHREAGED ; groove and of AND BENT ------*

STRIKE SINGLE BLOW WITH HAMMER

sufficient stiff- ness is shaped to fit the piston. A piece of a file is annealed and al- lowed to cool slowly from a cherry red in the ashes of a fire. Fig. 6. Handy This is cut to fit C clamp the groove and fastened to the inside of the tool with a machine screw. When hard- ened, it serves well to scrape the edges of the groove. 7. play in_ ball-and- socket connections such as is found on the tie rod of

the sides are smooth and parallel. A ram is made of hard steel to fit this hole accurately, yet not so as to. bind. Fill the cavity under the plug and the drill hole nearly full of heavy oil, insert the pin, and strike it with a hammer. The force of the blow will be transmitted through the oil. Thus a 100-pound blow on aram | in. in diameter will exert an upward force of 1600 pounds on a 1-in. plug. SWIVEL-TOP drawing-board stand (Fig. 5) was made from an old buggy wheel and its axle. The axle was cut down sufficiently to enable the table to rest on top of the hub, and then held upright by four 2 by 4 in. legs. The lower ends of these legs rest upon two cross pieces, which intersect with a cross-lap joint in the center. The axle rests upon the intersection, THREAD CLEANER Fig. 9. automobile steering mechan- isms can be taken up quickly by bending the cap slightly with light hammer taps. The cap is removed and one end is elevated a trifle, as shown in Fig. 8. Striking the center, a single blow will turn the flanges back so that when the cap is replaced the bolts will draw the center down on the ball. Since these parts are made of forged steel, this treatment does not injure them in any way. Wire cleaner NTERNAL threads of chucks some times hold chips, dirt and grit, even though the mechanic attempts to clean them with waste. A bent piece of spring brass wire, the ends of which are ground to fit the thread profile, as is shown in Fig. 9, will aid in the removing of this dirt. The spring keeps the points pressed lightly in the grooves as the device 1s screwed through the chuck, and the points sweep the dirt and grit ahead of them.

Page 83

, With quare flush pport tends amps, ubsti- 1 set- shown used. e and e ad- > need LOV- ‘arbon n-ring 1 tool shown comes r and sider- » and n ordi- n-ring ig tool of cold slight- 1an the nd of stiff- ped to son. A file is and al- » cool om a in the a fire. t to fit re and to the with a 1 hard- scrape ve. ill-and- 1s such rod of 1echan- quickly slightly ys. The vated a ing the flanges ced the on the f forged re them ; some- it, even ‘o clean f spring ground own in of this pressed evice is ind the head of BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY FEATURES FOR SHOP MEN F YOU are interested in the prob- lems of the machine shop, PopuLar Science Montn ty has in store for you several articles that you will be almost certain to vote the most helpful of their kind you have read. One of them, to be published next month, is “Getting the Most Out of Your Milling Machine.” Another, which will follow in a month or two, is “Remedies for Shop Troubles in Machining.”” Both are by Albert A. Dowd, consulting engineer. These two features in a way represent a new trend in the literature of the machine shop. They are the results of the efforts of the Editor of the Better Shop Methods Department to per- suade men like Mr. Dowd, who are out- standing figures in machine tool design and production methods—men respon- sible in large measure for the astound- ing achievements of the modern machine shop—to digress temporarily from their own field of abstruse en- gineering problems and place their wide and incalculably valuable shop experience at the disposal of the average machinist, to help him with the everyday problems of his work. Much noteworthy information is available on the higher branches of design and production management. A sample is Mr. Dowd’s own recent monumental work, ‘““Tool Engineer- ing,” written in collaboration with Frank W. Curtis. To publish material of such high caliber, but written from the standpoint of the average mechanic in the shop, is the object of the Better Shop Methods Department, and this coming series, in particular, will have a distinct dollars and cents value for every machinist. Spindle Button Will Aid in Locating Work Accurately iF truing up work and finding the location of points precisely in the mill- | ing machine, a spindle button made as shown will be found a great convenience. The button is a hardened steel bush- | ing fastened to a steel shank, straight or tapered, with a machine screw and washer. The diameter of BUTTON a the bushing should ae a be an even dimen- AT a 506 sion to facilitate calculations. The hole islarge enough to allow about in. play around the screw. The tool is in- serted in the spin- dle or held in a drill chuck, if it PRECISION MEASURE has a straight atten tr eecen shank. Tighten milling machine the screw just enough to allow the bushing to slip with some friction. Run the spindle at high speed and hold the end of a scale against the bushing until it revolves perfectly true; then tighten the screw. The button now forms an accurate cen- ter from which measurements may be taken in any direction with the height gage, verniers, micrometers, or with the feed screws of the machine. ee See es ee - Grinding Ourfiz. Consists of sae which can be fast- ar nch top, arbor BLACK & DECKER QUARTER-INCH PORTABLE ELECTRIC DRILL | : “With the Pistol Grip and riser Switch” Bench Drill ing Stand. The drill can be in- serted or de- tached quickly by means of handle clamp. $12, In Canada $16 ‘clamp washers and » anid gtinding wheel. Y figs ‘Csinada $4 Drilling in Metal or Wood Countersinking ‘Grinding Buffing Cleaning Carbon Removing Rust This one tool with attachments will perform all these operations. Your kit is not complete with- out it. Order today and experience the satisfaction of having a complete @® up-to-date tool kit. Orders and inquiries may be mailed to “THE BLACK & DECKER MFG.CO. 700 Pennsylvania Avenue,. _ Towson,’ Maryland

Page 84

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY PLUMBING & STEAM SUPPLIES General Motors Trucks GMC Provides Economical Power And Speed As Well—The Vital Factors in Any Hauling GMC trucks have reduced trucking costs materially. First, because the now famous GMC Two-Range Trans- mission has provided greater pulling power with an engine of economical size, operating at a governed speed. Second, by providing speed in combination with this pulling ability. For speed means dollars, when profits are reckoned by the ton miles carried in a working day. These economies, coupled with the even greater |savings gained through GMC Tractor Trucks with trailers, are profitable only with the power and speed ranges pro- vided by the GMC Two-Range Transmission. GENERAL MOTORS TRUCK COMPANY Gentlemen:—I am interested in what GMC trucks can do in the following business:—(Check business) Division of General Motors Corporation Pontiac, Michigan Lumber 0 Laundry oO Milling Contracting oO Transfer oO Store Delivery Bakery oO Building oO Furniture Bottling oO Oil oO Coal Other Businesses Name Address General Motors Truck Co., Pontiac, Michigan Department 47 O O O O O How to Make the Most of Planer and Shaper (Continued from page 76) shop. In either case they will prove to be a profitable investment for the small shop where more expensive equipment cannot, be afforded. Planing tapers, curves, irregular sur- faces, cam faces and the like is accom- plished by means of specially designed fixtures. The expense of such fixtures is warranted only by the prospect of suffi- cient work for the time and trouble of building them or when the customer is willing to pay for them. A typical ex- ample of this class of work is shown in Fig. 3. One very important consideration for the best results in planer work is the PIVOT BRACKET Fig. 3 (at left). Fixture for planing special curved work x and, Fig. 4 (be- A -. low), planer fit- \ tings that should be kept CAST !RON on hand in LEFT rue gay large variety AA he S rey rm 1! — T- NUT A U-STRAP =X cnt =X cnt STOP PIN angi IRON foundation for the machine. This should be of brick or concrete and the machine should be carefully leveled up with the platen removed. When a planer has been in use for several years it may develop errors that will cause considerable trouble in pro- ducing accurate work. General wear and rough usage, such as dropping heavy weights on the platen, cause this part to spring and warp out of its true plane. If this condition is very pronounced, the V’s will have to be re-planed and then a light cut taken over the platen, or even several light cuts. Before taking this cut, the cross rail should be squared up with the V’s. Another important matter in getting the most out of a planer is the provision of an ample supply of bolts, nuts, clamps, pins, toe dogs, and so on (Fig. 4). These should be kept in a box near the planer. A junior apprentice may be assigned the task of keeping these articles in good condition. It saves a great deal of a mechanic’s time in hunting up bolts and clamps or anything he may need for setting up a job. The supply of these articles cannot be too liberal, as a high priced machinist often is required to waste a lot of time looking for them. (Continued on page 83) —— 3 x Ve ey i pA i: a =

Page 85

op 10t, ur- 1ed 3 is left). for ecial york . (be- r fit- hat kept ff in iety BOLT )N ould shine . the > for that pro- > and eavy part lane. |, the 1en a even this d up tting vision LMmps, These laner. d the good of a s and d for these high od to them.

—_— BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

How to Make the Most of Planer and Shaper (Continued from page 82) A few variable speed planers are built, but most of the planers found in the | average shop run at one speed only and for this reason are rather slow for some | classes of work. The speed of a planer _may be set for planing steel at a cutting speed of 50 feet a minute and this speed will have to be used for brass or iron or any other metal, regardless of the theoret- ical cutting speed, unless the planer is one of the variable speed type. So now we turn to the shaper, a ma- | chine that is actually a planer in the sense that the cutting action of the tools | is identical. Being a variable speed ma- | | chine, the shaper will work much faster | than the planer on many jobs, although

it is not generally quite as accurate. Especially in cases where true parallel surfaces must be obtained, it requires

= ANGLE — BLOCKS

HEAD REMOVED SL UTING ouT INTERCEPTIONS ON THREAD mi] (ROTATEDON .

CENTERS) / (0) BOLTED TO TABLE BREACH BLOCK Fig. 5. Holding angular work in a shaper vise and one method of shaping curves

| considerably more skill to produce perfect _work on the shaper. Shapers develop | inaccuracies more rapidly than does the planer. This is due to a number of | causes; first, there is always a tendency | of the tool to spring away from the | work, particularly on long strokes and | heavy cuts; second, lack of rigidity in the | ram when the guides become worn and loose; third, the table sags and gets out of alinement with the ram, and, fourth, the work itself often springs. These are sources of error not common with other machines, and, in addition, it is difficult to keep the shaper always in perfect con- dition. With all these limitations, how- ever, the shaper has many advantages over the planer on small work and short cuts. Planing curved and irregular surfaces 1s done on the shaper much the same as on the planer, by the use of special fix- tures attached to the machine (Fig. 5). To get the most out of a shaper, the machine must be in the best possible condition at all times, abundantly sup- plied with tools and other necessary accessories, a good shaper vise, wrenches, parallel strips, bolts, clamps, and the like. The gibs should be inspected frequently and kept properly adjusted and the whole machine should be thor- oughly and properly oiled. Any inaccuracies existing in planers and shapers are usually discovered by | the cut and try method, although they may be ascertained by testing. Testing the accuracy of a machine is best accom- Plished by using a dial test indicator, Square, and level, nen

83

for mechanics—the new BROWN & SHARPE SMALL Toot CaTA.toc No. 29

narnia

hontai eae BROW a sHANeY ME BROWN & SHARCK MPG. CO m1 | rs ere 5% 4 . > —~ "=! ec Die Makers Square No, 3352 { E Adjustable Square No, 554 Price, $1.0 : Pa Ne Ocoee 8. | This sqpare is a quot i eens with either bevel ar narrow blade “ne with which die clearanen< A Beuenve, conaplete *

ab etre Bauare sent compete unio others pe orrecnd taverd and is whee very aw. tial bo Liam peatteres cneker for setting argos wad siratts pabterte The bhade con

fre amy angle ups ts K de grees wither aide of tiv 4020 WN beet sar seh tre prtwedes aon OM the printer taken due inbvartee

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OVER 2000 STYLES AND SIZES OF TOOLS THIS new catalog lists many new and improved tools that are invaluable to every mechanic. Over 2000 different styles and sizes of tools are listed. In addi- tion to being illustrated it contains much information concerning tools, tables, etc., making it a handy reference book that no mechanic can afford to be without. Ask your dealer for a copy. If he cannot supply you, write us direct.

BROWN & SHARPE MFG. Co. ph new a . ——s -_ Providence, R. | BS U. S: A. ya ‘all, it sks tho dost ladle Genta bay.

BROWN & SHARPE TOOLS Standard of the Mechanical World

Page 86

OCUS right on the spot where you’re working. Use your flash- light. Burrow right into dark or dimly lighted places. Use your flash- light. Your Eveready is ever ready to help you with those odd jobs. Indoors or out. If you have any flashlights not in use, put them back on the job with fresh, strong Eveready Unit Cells. And if you haven’t a flashlight, see the nearest Eveready dealer at once. Be sure to see the improved Eveready line. New designs. New

EVEREADY FLASH LIGHTS & BATTERIES ~they last longer

Light where you need it—uwse your flashlight! <a = ——

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features. Eveready standard fea- tures remain, as do the old prices— 65c to $4.50, complete with battery —anywhere in the u.s. A. Buy the improved Eveready Flash- lights from electrical, hardware and marine supply dealers, drug, sport- ing goods and general stores, garages and auto accessory shops. Manufactured and guaranteed by NATIONAL CARBON COMPANY, Inc. New York San Francisco Canadian National Carbon Co., Limited Toronto, Ontario

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

—t

Three Shaper and Planer Ideas that Will Save Time By F. J. Wilhelm OMETIMES it is necessary to produce a circular surface on some part of a job that will not swing on centers. In many cases a job of this kind may be handled on the shaper. In the central illustration on page 76 is shown a typical job of this sort and how it is held in the shaper vise. An arbor is made to fit the hole. It has a shoulder for the piece to butt against and is threaded on the outer end for a nut. There should be a washer between the nut and the work. Draw up the nut just tightly enough to allow the work to rotate on the arbor with a little friction. Set the tool in the center of the

RIGHT LEFT Extension head for planer and a square- nose tool that replaces two bent tools work and roll the piece around to the point where the circle starts. Feed the tool in to the depth of cut desired and

feed the work to the tool by pulling it | around by hand just enough to take a normal cut. An extension head is a valuable planer | accessory for tools that will not pass between the housings of a small planer. These devices are usually homemade | affairs and cost very little. In the accompanying illustration, Fig. 1 | shows a strong, yet simple design of ex- tension head. It is made from a pipe of large diameter and two cast-iron pipe flanges to match. The pipe may be as) long as necessary and the diameter will be governed to some extent by the diameter of the bolt circle on the saddle. When taking a side cut with a down) feed on a shaper or planer, a square nosed tool (Fig. 2) with the corners well rounded | is superior, I find, to any other style. | When set over at an angle to the work, it | will get under the scale and follow 4 straight line much better than the con- | ventional bent, round-nosed tools. The latter style (Fig. 3) must be made in pairs, one right and one left, but the square-nosed tool may be used on the | right or left with equal facility and with- out any change of form. In addition to being more efficient from a production standpoint, there is also a considerable saving in tool steel investment.

—— eee ee SL ee

EPO ROAR MEMEBERS EAB BEEPS MIT OBERT 8 wt stb t

ae Dee i e Se : cages re Bis sone

Page 87

li, Ideas roduce rt of a rs. In nay be central typical in the fit the iece to e outer washer raw up Ow the a little > of the uare- tools to the eed the ‘ed and ‘two guide studs pass through rollers, _push the bent form out of the die and fing it | take a | » planer | ot pass | planer. | nemade | 1, Fig. 1 | 1 of ex- | pipe of yn pipe | y be as} - will be iameter | a down | ‘e nosed ‘ounded r style. work, it ollow a he con- s. The nade in hut the on the | d with- | ition to | duction | iderable ae Additional Shaper Shortcuts | By Henry S. Laraby ae forms of wire and sheet metal | may be produced with a shaper by | the use of simple bending dies held in the | | vise (Fig. 4). The usual way is to cut the | | wire to the proper length and lay it on the | die with one end against the stop. The | which reduce the friction. The shaper is run at any suitable speed and the pieces of wire may be put in place without stop- ping. Set the stroke just long enough to leave it clear for the next piece. The use of a cutting-off die, like the one | | shown in Fig. 5, is a rapid and economical | method of cutting off wire lengths. Surface grinders are hard-worked ma- chines. When you are unable to get a | machine or the shop lacks one, a shaper SHAPER © SHEAR CUT SHAPER TOOL HARDENED PLATE BLOCK CLAMPED IN SHAPER VISE ADJUSTABLE STOP | Bending and | cutting wire and grinding with a shaper TOOLPOST GRINDER SHAPER VISE may be a life-saver for a rush job. With an ordinary portable toolpost grinder, the shaper will do an excellent job. The grinder and the work is set as in Fig. 6. Simple Shop Trammel Made Mainly of Pipe Fittings A TRAMMEL head may be made easily by using a }4-in. pipe coupling, a ]4-in. plug, a 14-in. nipple 114 in. long, and a piece of 3¢-in. drill rod 1 in. long. Drill a 14-in. hole in the coupling 3% in. | from the end for the trammel bar, which may be 14-in. brass | or steel welding rod. The plug is screwed into the upper end of the coupling to bind this rod. Grind t VY," short steel rod to “ Pen point and insert it in STEEL POINT the nipple either by -= heating the nipple and shrinking it on, or by pee soldering or brazing the parts together. . Screw the nipple in the | lower end of the coupling. A piece of | chalk or a pencil may be used in place of | one of the steel points.—W. H. Wray, Toronto, Ont. an BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY ae gee lf “erate had owned a file— Life would have been a bit smoother for him! Your life, even, will be decidedly smoother through an understanding --and use--- of good files. Yow 'll find hundreds of practical, every-day uses for NICHOLSON Files---in your shop, your garage and about your home. And NICHOLSON Files are uniform, sharp, enduring. That’s why they’re first choice among skilled tool users, everywhere. First-class Hardware Dealers carry complete stocks of NICHOLSON Files NICHOLSON FILE CO. Providence, R.1., U.S.A. MOL 5 SSe OSA. (TRADE MARK) | OL NOT OF OF OG ma ma aN POG IG POI Of PP mL Off eh, | NICHOLSON FILES ~a File for Every Purpose | (SSS SSS SSS SS SFIS SESS GOH} ||

Page 88

The Spirit of Pioneering Impatience with present facilities, a restless searching for per- fect things—these have driven men to discovery and invention. They possessed the early voyagers who turned their backs on the security of home to test opportunity in an unknown land. They explain the march westward that resulted in this settled, united country. And they have inspired the activities of the Bell System since the invention of the telephone. The history of the Bell System records impatience with any- thing less than the best known way of doing a job. It records a steady and continuous search to find an even better way. In every department of telephone activity improvement has been the goal—new methods of construction and operation, refinement in equipment, discoveries in science that might aid in advancing the telephone art. Always the road has been kept open for an un- hampered and economic development of the telephone. Increased capacity for service has been the result. Instead of rudimentary telephones connecting two rooms in 1876, to-day finds 15,000,000 telephones serving a whole people. Instead of speech through a partition, there is speech across a continent. Instead of a few subscribers who regarded the telephone as an uncertain toy, a nation recognizes it as a vital force in the busi- ness of living. Thus has the Bell System set its own high standards of service. By to-day’s striving it is still seeking to make possible the greater service of to-morrow.

AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES BELL SYSTEM One Policy, One System, Universal Service

[t's easy to build up a profitable business at home with the Pony Bench aS Saw. Make all gr of q woodwork. Easy Ss interesting work — big 2 profits. Six machines at At most druggists’ the price of one. Saws, sands, drills, grinds, buffs. Saws $1.25, or por A 114” stock. Duiiven by 1/3 h.p. motor attached to any light Liberal trial bottle, ne ig 10 cents postpaid. W. F. YOUNG, Inc. 350 Lyman St, Springfield, Mass. Sold on Money Back Guarantee Write for descriptive folder on Bench Saws, Band Saws and W. B. & J. E. BOICE, 1730 Norwood Ave., Toledo, 0

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

HE lead ham- PIPE HANDLE | | trated will not | become battered | usual type. It | also will strike a ' more __ balanced | blow, as the hang | of the hammer is | little disturbed | by constant use, owing to the side wall Side Outlet Tee i of Lead Hammer mer illus- as rapidly as the

reinforcement. A 2-in. tee with a 1-in. side outlet is used; the handle consists of a piece of l-in. pipe. A ring is set over the outer ends when pouring the lead so that there is a projection of lead about 1 in. on both sides.

How to Remove a Battered Toolpost Screw OOLPOST binding screws often be- come battered or upset on the end so that they cannot be removed. Continued use in this condition makes matters worse; sometimes the screw gets so bad that it cannot be moved at all. The principle cause of this is a soft point. To remove a screw in this condition is a simple / operation. Place the Hiisaw' head end of the screw in el a vise, insert a hacksaw eR Ao

> Se , AN) dy

YETI, LC blade through the tool Uf cs opening, turn the blade at right angles to the frame, and saw a slot about 1 in. deep. Then saw another slot at right angles to the first. This leaves four quarter sec- tions that can be broken out easily with a ehisel. The screw then may be re moved.

Lathe Center from Shank of Broken Drill NE of the lathe hands in the steel plant with which I am connected complained that the tail center on his lathe was too soft. Told to make a new one, he selected from the scrap pan a broken high speed drill. This he cut to the required length and machined the end. The working end he then had hardened in the tempering room, after which he ground the point. Several centers have since been made in the same way at half the cost of our previous method.—F. N.C. |

Brazing Broken Twist Drills in Special Shanks HEN _iarge size twist drills are acciden- tally broken, it pays to. salvage them if possible. A method I have used successfully 1 illustrated. The broken drill is inserted in a special shank made as shown and brazed in place. This is cheaper than buying a new drill.—H. W.

——

Page 89

with a Steel Square CARPENTER’S level may be ad- justed accurately by the method illustrated. A steel square is clamped in a bench vise with the tongue, or short | part, vertical and | Adjusting a Carpenter’s Level UTLET ee with the blade, or " iF ew long portion, hori- ee zontal. ’ ae re For horizontal fh A adjustment place h the level on the le wall | square blade and note carefully the utlet is position of the lece of bubble. Then turn e outer the level end for it there end and again note yn both the bubble’s posi- SUK NARS tion. Loosen the How the level is Vise and tilt the red tested for accuracy square to bring it exactly level. Turn eH | the level adjusting screw until the bubble ten be & | js exactly centered and the level registers BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 2endso & the same turned either way. ntinued fe Since the vertical tongue of the square matters FF must be exactly plumb, proceed to adjust ies the & the plumbing level glass by testing the l that it level in a vertical position. latal. §& Be careful to place the level squarely on ause of FF the square, for a diagonal tilt in either it: direction will affect the result.—F. W. P. crew in | —_ Stand Holds ‘‘Rough Stuff’’ and scene Varnish Rubbing Materials 1acksaw ‘he tool DRAWER FOR RUBBING BRICKS, ETC e blade to the {1 n. deep. = | ngles to = ter sec- —— y witha Zu be re Z/7” IER PAIL ik of = ; | gre he steel | nected | (COLOR varnish and “rough stuff” rub- - on his | bers will find the portable stand illus- e a new | trated a convenience on the rubbing-deck. > pana, | It can be constructed by the handy man e cut to | of the shop from lumber usually on hand the end. | for repair work.— VERNON F. CLAYTON. dened in| @ | sng ec | A Trysquare with Knife Guide y at half | CARDBOARD, heavy paper, tracing -F.N.C. | “cloth and similar materials can be | | cut rapidly and accurately by using a try- We | Square made as shown. A slot just wide Drills | | enough to allow the knife to work freely | is cut through the | center of a leg of the square, parallel with the edges. The square should 4 be hard wood and KEN END all edges should be | sfully is smooth. The knife og tail is placed in the — po slot and drawn nian . . toward the ope- per tha For cutting cardboard, rator.—JAMES E. — Paper and cloth NOBLE. mere ——— lla ces HAT millions of people want, and know they want, is sure to be forthcoming! This new Magnavox certainly proves it. Handsome enough in its dark blue and gold finish for the finest mansion — sturdy enough to stand rough usage at camp —cheap enough for the most modest salary. Above all—so clear and mellow in tone, so true in pitch, that even your critical musical friends will be convinced that the “Radio art” has arrived. M4 requires no battery—a definite evidence of achievement. At all good dealers THE MAGNAVOX CO., OAKLAND, CALIF, New York Office: 350 WEST 31st STREET Canadian Distributors — Perkins Electric Limited, Toronto, Montreal, Winnipeg © 8C

Page 90

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY turn of the Cap The right tension for the work UST turn cap on handle J of “Yankee” Automatic Push Drill No. 44 to regulate tension. You get the right pressure for hard wood, soft wood, small drills, large drills. “YANKEE” AUTOMATIC Push Drill No. 44 is the only drill with adjust- able tension. It has seven different tensions. No other drill but this has a magazine handle that opens up toward the chuck, exposing eight drill points, heads up, for easy selection.

“Yankee” Automatic Push Drill, No. 41. Without ad- justable tension. Some other ‘‘YANKEE” Tools Ratchet Screw-drivers Spiral Screw-drivers Quick Return Spiral Screw-drivers Plain Screw-drivers 134 to 30 in. blades Ratchet Breast Drills Ratchet Hand Drills Dealers everywhere sell “‘Yankee’”’ Tools. FREE Tool Book with ih ji. 7 trations , rnd scriptions of all “Yankee ” Tools. Yours on de-

request. . NORTH BROS. MFG. CO. PHILADELPHIA, U. S. A. “YANKEE” TOOLS Make BellOv Mechanicy

Saving Floor Space in a Crowded Machine Shop By Dwight Donald ” SMALL shops, with the present high cost of rented buildings, it is often a problem to obtain the necessary floor space. All such shops have machines that are used only occasionally. The area occu- pied by them frequently can be used to ad- vantage for extra bench room. Skeleton | benches with solid tops are built and | braced between both pairs of end legs and | one pair of side legs, in such a way that

| | wire rod. Not only is floor space saved, | | but the terrific noise and vibration of the | | when mounted on casters they can be rolled over any low-built machine. For several | years past this arrangement has served a dozen different uses in my own shop. We also have economized space by building in closets under tables and by hanging a closet from the ceiling against the wall. The lat- Y% tony, fisescnew ter, which has swinging doors on es CHECK— Y4CAPSCREW the side and ends made of matched boards, keeps office supplies and ship- ping material free from the greasy dust that is the bane of the ma- chine-shop office. Additional space A conductor tube for screw machine has been gained by doing away with the | pipe rod standards commonly used in con- nection with automatic screw machines. The conductor tubes now hang from the ceiling, parallel to the floor, each sup- é, ; ~<a How Bleachodent Whitens Dark Teeth In Three Minutes Bleachodent Combination contains a mild liquid to soften stains—and a special paste which gently removes them. Dull, yellow or tobacco-stained teeth are made flashing white, sparkling clear— almost while you wait! Perfected by two prominent dentists. Just use liquid once a week—paste every day. Meeps teeth wonderfully white and lustrous. Don’t go around with bad looking teeth. They spoil appearance, and besides cause tooth decay, and | bad breath. Get Bleachodent COMBINATION } |

(containing both liquid and paste) for small cost. Distributed by Bleachodent Dental Laboratories and | sold by drug and department stores everywhere.

Home Protectio

with an ASTRA Automatic | will cost little ae

Nearly every man wants a gun in the house—he feels better able to protect his family. We are able to offer these | Genuine Astra guns at special prices | because we bought before recent tariff | raises became effective. Really fine guns, beautifully finished, hard hitting. Use standard ammunition. Order | direct from U. S. importera ported at either end by a 14-in.-diameter | | screw stock revolving in the tubing as it | | feeds into the automatic is much reduced. The hanging rods should be cut to the proper length with allowance for bending | the eye, 134 in. inside diameter. This pro-

vides room for a leather collar to be wrapped around the pipe passing through the eye. §/16-in. clear hole should be drilled, paral- lel to a plane passed through the eye, and The leather acts as a silencer | and reduces vibration. Above the loop a | 25 calibre—7 shot—C. O. Q. Automatic. 25 calibre—7 shot—Astra Automatic, 25 calibre Astra with triple safety. 32 calibre—10 shot Astra, extra magazine, 32-20 and 38 cal. swing-out cyl. revolvers. We guarantee every gun against defective work- manship; brand new; of Drop Forged Stee! Through- out. Before buying any weapon INSIST on this | guarantee. SEND NO MON unless you | wish, State model desired—pay postman on delivery plus postage. Satisfaction guaranteed or money re- funded. Write for new firearms catalogue. CALIFORNIA TRADING CO. | Dept. 1-8, Terminal Bldg., Los Angeles, Cal.

extended as a 14-in. tapped hole through | the tail of the loop directly opposite. nut screwed on, to clamp the eye firmly around the leather collar and feed pipe. A %-in. lagscrew should be welded on the upper end of the rod to screw into the beam or planking above. This device has been used in connection with our several automatics for five years. | tool

This Special Woodturning Tool | = Makes Deep, Smooth Cuts W OO D- oF TURNING shaped as shown takes a very | deep cut and leaves | a smooth finish. | It works equally | well 45° BEVEL in a wood- EDGE turning or an en- gine lathe. Regular tool steel bar stock is used. It is drawn out to a taper, bent ' to a semicircular form and tempered. A | binding screw then can be passed through | | the two parts of the loop and a check - ‘Umbrella Tent—No CAMP IN =< COMFORT (Pat. Pend.) “OUTODOOR* Auto Tents embody patented features found nowhere else. Made of highest quality, close count, specially woven drill; absolutely water-proof, mil- dew-proof and shadow-proof. Ground cloth sewed in. Umbrella Auto Tents come in regular style; without gacenter pole; or with Cot Transom (pat’d.) Y Combination Picnic Outfit Lunch {fn comfort on lawn or in camp. Con- vertible into full double bed. Table — to carry outfit. Nothing like it. WRITE TODAY for complete cata- 4! of tents and camp equipment- SENT FREE. U.S. Tent & Awning Co., 718 N. Sangamon St., Chicago, Ii

Areyou undecided about yourfuture? § Are you groping blindly wondering § what you ought to do? Would you like to know for just what kind of Bm work you are best fitted? Would yonliketo Rig Earn MORE MONEY Immediately? & We can helpyou decide. We canshow you Bixasams how to get ahead quickly—how you can : make most of rour abilities and how you can be a big money maker,» You will be under no obligation if you will drop a line for full information. DIRECTOR PERSONAL ANALYSIS Dept. PAC 75 Drexel Ave. and 58th St., Chicago

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tes liquid gently tained lear— ninent every strous. They y, and TION 1 cost. ies and re. n itifully Order eatures r, close of, mile wed in. without t’d.) atfit mp. Con- d. Table hing like lete cata- lipment= g Co., ti ago, Li. | bolt. Screw Heads Slotted Rapidly in Simple Lathe Fixture HE owner of a small shop sometimes has the job of slotting a number of machine-screw heads. To do this with a hacksaw is tiresome. It is much quicker to use the rig illustrated. The base is made from a piece of meager / steel 2 by 2 by 51% | — in., with a recess oP\_--? machined on one jt side and with two projecting lugs. One lug acts as a i knock-out ‘block; For slotting screws = +e other is drilled and tapped for a 3¢-in. feed limit screw. A hole is drilled in the proper location for the fastening FASTENING BOLT The hand or feed lever is fastened to the | base with a 5-in. stud or cap screw. | This lever is drilled in the proper location |—according to the center of lathe—to | receive the screws to be slotted. If many | sizes are to be slotted, the hole may be | drilled large and bushings of various | sizes made to fit the screws.—F, N. C. | A Shock Absorber for an | ! Auto-Towing Cable /\AATERIAGS dIvIDED TOWING CABLE | | taken from ‘ | the junk. box were | used in making the’ | tow-cable § shock | absorber illus- |trated. The two , | plates are drilled WP" WM 4 | at each end with IRON PLATES | bolt holes, and in 3fe'* 3°x10 | the center for the For smooth towing | cable. If a steel cable is used, the ends may be | sweated in place; if ordinary rope, the | ends are knotted. The springs used are | automobile clutch springs, although any fairly heavy springs will serve the | purpose.—HARRY G. SCHULTZ. | Stiff Protectors Shield Freshly _ Varnished Surfaces from Dust NS Piss. ey NS SA lilc Ye) PAPER BOARD PROTECTOR AK “SUPPORTS” BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY **The Critic”’ I IGHT protectors made of wood, wall- keeping dust and dirt from settling on with closed cars and the other for open cars. The same method can be used ‘o protect furniture or other woodwork | | While varnish or enamel is drying.—V. C. t— ~ board, or cardboard are useful in | freshly varnished horizontal surfaces. | Two applications of this idea to automo- | | bile finishing are shown, one for use | LL creative effort comes in for its share of criticism. You know that—that is, if you veever tackled one of those round-the-house carpenter jobs. But maybe the criticism should have been directed at your tools! Why not head-up your tool kit today with a Simonds Hand Saw, Hack Saw and File? They’re produced by an organ- ization experienced in making cutting edges of tempered steel since 1832. They're RIGHT! Ask your dealer today, but be sure you pronounce the name SI-MONDS. SIMONDS SAW AND STEEL CO. **The Saw Makers” Established 1832 Fitchburg, Mass. Branch Offices in Principal Cities

Page 92

90 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY All Set to Produce What ?—and When? Your machine is “‘all set’’ to deliver the product—at the best rate you've developed in its design. Then the question: ‘‘What IS its best rate of work?’ Next the question: “How to know when it’s DOING its best?” —as indicating whether it’s well operated and watchfully run. Better equip the machine to turn out something besides question- marks. Make it turn out produc- tion records—on a COUNTER The Set-Back Rotary Ratchet Counter below is for machines such as presses and metal-stamping machines, where a reciprocating movement indicates an operation. ~~ + ™ Mivweennonern Registers one for each throw of the lever and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure-wheels, as re- quired. Price with four figures, as illus- trated, $11.50—subject to discount. (Cut less than V% size.) t-back Revolution Counter of similar model, $10.00 (lisé). Thissmall Rotary Ratchet Counter (No. 6) counts reciprocating movements of the lever, as required for recording the output of innumerable small machines. When the lever is moved through an angle of 40 to 60 degrees, the counter regis- ters one. The further the lever is moved, the higher the number registered. A complete revolution of the lever registers ten. This counter can be adapted to no end of counting purposes, by regu- lating the throw of the lever. Price. $2.00. (Cut nearly full size.) Small Revolution Counter, also $2.00 Everything you could use ina counting device is shown in the 80-page Veeder booklet. Your reguest brings it promptly. The Veeder Mfg. Co. 44 Sargeant St., Hartford. Conn. FRIEND of mine, the other day, A was being entirely too conscien- tious in the construction of a cabinet. He was working on a pine buffet top, about 20 in. wide, glued up from two boards; and across the under side he had glued and nailed 1 by 2 in. cleats to make what he thought was a very solid and substantial job. “T’m sorry to see you putting those cleats on in that way,’ I remarked. He looked at me in surprise. ‘‘Why,”’ he replied with some heat, ‘‘you know how hard it is these days to get well- seasoned materials. If I don’t put on the cleats, this top will simply warp until soon it will be of no account at all.” “You are build- ing against one fault of shrinkage while ignoring an- other,” I said. “Leave off the glue from the cleats and you will be all right.” My friend was entirely correct in guarding against warping. All car- penters and most amateur wood- workers know that there is only too little thoroughly seasoned soft wood to be had; and the old rule of gluing up boards with heart and sap sides alternately up to minimize warping is largely useless, since the heart side of a board, though growing nearer the dry interior of the tree, may actually contain more moisture than the sap side because of having been ripped from the sap edge of a timber that had dried out fairly well on the surface, but was still green in the center. And even with the right material, the rule hardly helps where wide stock is to be glued edge to edge. Stock 20 in: wide will shrink 1% in. across the grain and it must be taken for granted that this will occur. If, therefore, the cleats are glued, the enormous force developed in shrinkage is unable to draw the outer edges toward each other, as it could if the top were lying free, and it relieves the strain by attacking the weakest points in the top— oftentimes the glue joint, or a check or windshake not seen when the top was made. That causes splits in the top and 3-PLY PANEL VENEER RABBETED | the parting of the boards at the joint. On the other hand, if the cleats are RABBET In concealing the effects of shrinkage, Figs. 2 and 4 are better than Figs. 1 and 3 ‘How to Outwit the Shrinkage Jinx! merely nailed on (Fig. 5) with short nails driven in at various angles to obtain a dovetailing effect, there is enough re. sistance to the shrinkage of top or bottom surfaces to prevent warping. At the same time, the side spring in the nails is sufficient to allow the front and back edges of the wide board to be drawn toward the center. In nearly every case, checks are avoided. This is equally true for screwed-on cleats. If, to strengthen the glue joint, additional reenforcement seems essential, apply glue to the cleat for an inch each side of the joint. Since shrinkage will show itself on a cabinet, it should be disguised as far as possible. Figure 1 shows a favorite way of finishing the edges of the cabi- nets often built in modern homes. A molding is = run around the edge and ends of the top, giving it a heavy, ornamental appearance. But the grain of the end moldings is across the width of the cabinet top, so that when the top shrinks, if it is solid and not ply- wood stock, it will draw away from the front fascia. The end molding will prevent the front molding from following the top in its contraction. These openings, as in Fig. 3, are defects to be noted in many well-built houses and on dressers, tables, and other articles made by amateur woodworkers. Shrinkage, however, can be disguised. Drop the upper edge of the fascia mold 1g in. or more below the edge of the top, and fit the top into a rabbet in the mold- ing, as saown in Fig. 4. When the top shrinks, more of the upper edge of the fascia will be uncovered, and the paint or varnish will break at that point; but no light can be seen through and the ex- posed wood will not be noticeable. In the building of cabinets in a house, the use of 3-ply panel veneer 3¢ or % in. thick for tops is recommended. No shrinkage takes place in this material, and the outside veneer, extending the full width of the top, is without joints and presents a fine grain for staining. Cleats may be glued to the under side for stiffen- ing, and the finishing of the edges may be as shown in Fig. 2.—E. L. | SHRINKAGE OPENS" _ JOINT HERE ae SHRINKAGE OPENS NO CRACK Refastening Brush Backs ETAL backs of hair brushes that become loosened, may be replaced permanently by the use of sealing wax, such as is used in canning. All the old fastening material in the metal shells should be removed. Fill the shells nearly, but not quite, full of sealing wax melted | sufficiently to run well. Press the top flat surface of the upper part of the brush down into the soft wax in the same position it occupied before becoming | loose. Cut.off any surplus wax around the edges. Within a short time the wax will harden and the brushes will be as usable as ever. The wax should not be re-melted by immersion in unnecessarily the hot water, which would bristles as well.—G. E. B. injure

Page 93

Inx rt nails btain a igh re- bottom At the ie nails d back drawn "y case, lly true ngthen cement e cleat lf ona ; far as ite way ig the e cabi- built in mes. A iS run e edge of the p it a imental But of the ings is width net top, 1en the , if it is ot ply- , it will y from fascia. nolding nt the ng from she top raction. ings, as n many tables,. imateur er, can ia mold she top, e mold- the top of the aint or but no the ex- , house, r X% in. i. No aterial, ing the nts and Cleats stiffen- es may of the 1e same coming | around she wax 1 be as not be essarily re the HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Blueprints Offer Many Good Ideas to the Home Worker | pe valuable the Home Workshop series of blueprints is to home craftsmen is indicated by the above photograph, which shows a sewing cabinet based on POPULAR SCIENCE MONTHLY’S Blueprint No. 1. This exceptionally fine piece is the work of Rufus E. Deering, of Clements, Kan. Mr. Deering prepared the article on constructing a walnut chair on page 73 of the July issue. When a craftsman of his ability makes use of the blueprint service, it is obviously to the advantage of woodworkers of less experience to avail themselves of these careful plans. Complete List of Blueprints AXY one of the blueprints listed below can be obtained from PopULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to pro- vide, upon request, information rela- tive to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 225 West 39th St., New York. GENTLEMEN: Send methe blueprint, or blueprints, I have underlined below, for which Timelee......... cents: No. Title Price Bec as re 25¢ 2. Smoking Cabinet............. 25c 3. Book Trough End Table........ 25c 5. Kitchen Cabinet............... 25c 6. Two-Stage Radio Receiving Set. .25c eo ee re 25c 9. Arbor with Gate and Seats...... 25c¢ BD ee A re 25¢c 11. Bench and Tilt-Top Table...... 25c 12. Electric Washing Machine..... 25¢ WSs Rem MAMBORR 15 \ci 5,0 45.6. scar h.0,3 006.0") 5 0 25c 14. Toy Train, Horse, and House... . 25c 15. Home Workshop Bench........ 25c 16. Inlaid Radio Cabinet........... 25¢ 17. Cedar and Mahogany Chest..... abc 18. Telephone Table and Stool...... 25c 19. Grandfather’s Clock........... 25¢ 20. Kln€ Bop Oemies. cc oe. scien sess 25¢ 21. Colonial Writing Desk.......... 25c 22. Girl’s Cabinet and Desk........ 25c 23. Pergola Garage............-..: 25c 2S. Gateleg Tae... 6. ese cece sss 25c 25. Sailing Outfit for Canoe......... 25¢c 26. Baby’s Crib and Play Pen....... 25c 7. Kitchen Cabinet Work Table... .25c 28. Pullman Play Table............ 25c 29. Toy Tea Cart, Garage, etc...... 25c 30. Tool Cabinet, Bench Hook, etc. .25c Si. Priscilla Sewing Cabinets....... 25¢ 32. Chinese Game Table........... 25c 33. Pullman Dining Alcove......... 25¢ 34. Trellises for House and Garden. .25c EUG TEe Sele tos tay tee ea POT cop ast Lai sisters Ld (Please print) Street "Experience is the Vital Factor in Excellence” Thousands of artists have used the same colors that Gains- borough used to paint the famous “Blue Boy,” but there is only one “Blue Boy.” The difference is that Gainsborough knew how to apply and mix the colors. GnOMPSsO”N SPEAKER The engineering principles of mechanics, electricity, and sound have been applied to the Thompson Speaker by an organization that has made radio products exclusively for the last 14 years. The “reed”—or driving armature—in a Thompson Speaker is not found in an ordinary speaker, and this is just one of 7 Thompson features—reasons why there can be no distortion in a Thompson regardless of volume. Why “set along” with any speaker when you can get the best that our experienced radio engineers can build—the Thompson. $35 at good dealers. The Thompson Neutrodyne, which combines features not found in the average neutrodyne, is made by the same organization. $150 without tubes and batteries. R. E. THOMPSON MANUFACTURING CO.: Manufacturers of Wireless Apparatus for the U. S. Army and Navy and numerous foreign governments 150 NASSAU STREET +» » NEW YORK, N. Y. FACTORY: JERSEY CITY, N. J. = 4 y (f THOMPSON NEUTRODYNE aS AS = Oe Licensed under Hazeltine Patent LM) E> F Nos. 1,450,080, 1,489,228 and other patents pending SEND FOR THE INTERNATIQNAL CATALOG International Body Works, 914 W. Ohio St., Dept. 8, Chicago, IIL . toyou Free for 30 daystrial on approval. Your (aiieed choice of 44 Styles, colors and sizes of /AV and accesso- the famous Ranger Bicycles. Express pre- WY ries for Fords 35; Bicycles $: 1.60 and up ifdesired.Manyboysand Prices. Save a Month fsiebeed Yl big money on cycle earn the emal monthly payments. seats wheels, lamps and equi t at ives half usual pclceas Welteice remarie able tactory prices and marvelous offers. CYCLE COMPANY Write us Mea DEPY. 1109 CHICAGO today far, N Our net price list. Full line of auto bodies bo es by buying Direct from r " Fi y. FOR FORD—Prices from $27.85 up._ Factory to consumer direct—Pay only One Profit tee Be Resta Wate ee aR ERED tad en bea Sells for $1.25. Agent’s Sample 65c:! New Self-Filling Bamboo Fountain Pen with Stylo Point SCREW CAP PEN RETAINER FITS INTO BARREL ABSOLUTELYS._FRICTION-TIGHT PREV’ i) > ENTING TWISTING OF TUB SENSES 4{TS THE POINT. HAS EIGHT GROOVES FOR INK TO FEED Imported from Japan. “It makes Carbon Copies.” Guaranteed forl year. Hustlers Making $20 Daily! Money refunded if you don’t think it’s the best pen you ever wrote with. Up to 150 per cent Profit. Send for quantity price list and distributing plans. F. SPORS & CO., 199 S. 4th St., Lesueur Center, Minnesota

Page 94

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

PLIXRAS

Ever notice the name stamped on the pliers in the kit of the profes- sional mechanic or electrician? Ask them — they’re good folks to follow, when you are choosing your own kit of tools! Of course there’s a reason for their preference. stance, of The shape, for in- any Klein Plier is the result of over a half a century of design and redesign — the keen knives are individually tempered to give long, sturdy service —the casy spring of the handles and the balance of the tool is just right for maximum comfort. Ask your hardware dealer to let you see a pair of Klein’s Side Cut- ting pliers next time you’re in — q

i xemegeh t | POCKE! { | 720 cmon | 3220

feel the hang of them yourself. When you buy pliers — make sure—ask | for Klein’s. Klein's “ Pocket Tool Guide” is full of useful tables for the electrician. Drop usa card for one. It’s free for the asking. BELMONT AVENUE CHICAGO, ILL. © & Sons Mathias

Building Radio into Your Home (Continued from page 71) type of wiring is shown that provides an aerial and ground outlet in several rooms. This method of wiring is for use with a commercial set that has a built-in loud- speaker and the whole set is intended to be carried wherever it is used. All outlets should be connected in paral- lel, as Fig. 1 shows. The set required is the same as for operating an individual loudspeaker. Ordinarily one corresponding in volume to a regenerative set with two stages of audio-frequency amplification is ample. In the summer, it is often desirable to change aerials to suit the atmospheric con- ditions. For this it may be well to provide the regular outdoor aerial and a second one, consisting of about 1 lb. of bell wire strung around the picture molding, or an inside aerial stretched through the attic. A single-pole rotary switch, with two con- tact points, will enable the change to be effected instantly. When static or other interference is very troublesome, a loop aerial is a life- saver. If a regenerative set, using a

|agoP AERIAL FIG.4 JACK PLUG

Wiring diagram, showing method for con- necting outdoor, indoor, or loop aerial at will coupler with a variable condenser con- nected across the secondary, is used, it may be converted readily for use with a loop by connecting a double-circuit jack in the circuit, as in Fig. 4. The plug is attached to the end of the upright post of the loop and plugged in whenever needed. If a phonograph with a cabinet is avail- able, it is an exceedingly good plan to build the set right into it. This will save space, insure an artistic cabinet, and make use of the mellow tone resonance of the usual phonograph sound chamber. The style chosen for illustration in Fig. 5 is a typical one, and will serve well for an example. In one side is located the reproducer and the horn, and in the other are the shelves for records. Measure the distance between the two walls of the record compartment, and cut your panel to that length. The height necessarily depends upon the particular apparatus you must mount, but will gen- | erally be the equivalent of the space be- tween two or three record shelves. A baseboard of wood, from %% to 1 in. thick, of the width of the panel, should be fastened to the panel with screws and brackets. The depth of this should be governed by the depth of the cabinet, allowing, of course, for the thickness of the panel and the amount of set-back that is necessary to take care of the pro- jection of the dials. Leave ample room for the door or doors to close. If you use dry-cell tubes, it is entirely feasible to include both the A and the B —.. batteries within the cabinet. Pariitions of thin wood will help keep them in place, If the cover does not open so as to make the batteries accessible when they have to be inspected or changed, a door will have to be made in the back of the cabinet, or else the entire set will have to be re- Typical way of installing set in phono- graph cabinet, With doors omitted for clear- ness. The set is are- movable unit, as shown below Se "\\ 1@ +4 i { JS ee hl

RADIO PANEL FIG.S BATTERY COMPARTMENT

roll oe se | iii 4 ly *

moved bodily each time a change is to be made. Strips of wood, about 14 by 34 in., are fastened with screws to each side of the inside of the cabinet to serve as a support, upon which the base can slide like a drawer. A vertical strip of simi'ar ma- terial should be fastened on each ice, ex- tending from the top of the cabinet to the upper side of the base. Two screws through the panel at each side into these strips will hold all the apparatus securely. In uprighttypesof phonograph cabinets, a set may be placed in the record com- partment or even built to fit into the cover if it is fairly deep. How this can be done may be observed by studying the ingeni- ous arrangement of parts in commercial sets sold to fit into phonograph lids. If the tubes used require a storage bat- tery for their economical operation, this Sa JI] tf \]}o_> < CHARGER

o9 8 °@ c= STORAGE BATTERY

B BATTERY VENTILATING

pF CHOLES) = =

Battery-charging box and diagram showing arrangement of parts and wiring diagram will have to be left outside. The next best plan is to build a separate battery box.

In Fig. 6 is suggested an arrangement by which a storage battery, its charger, and | the necessary B battery may be placed | (Continued on page 93) )

ee

Page 95

Lv titions place, > make y have or will abinet, be re- ypical ay of stalling et in hono- raph abinet, i-th oors mitted x clear- ess. The t is are- 1ovable nit, as hown below is to be in., are - of the upport, like a lai ma- ide, ex- t to the screws 0 these ecurely. abinets, ‘d com- 1e cover be done ingeni- mercial ids. ige bat- on, this B &TTERY ILATING ES owing agram ext best ry box. nent by yer, and | » placed a HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Building Radio into Your Home (Continued from page 92) in one box and the whole hidden under the console, or even in another room. | A double-pole double-throw knife- | switch is mounted on the front of the box, ‘along with an electric-light plug outlet /and the A and B battery binding-posts. | Bv throwing the switch to one side, the | battery is placed on charge, and by throwing it to the other side, it is con- | nected with the set. Holes should be drilled in the top of the box to allow the ‘escape of the battery gases. | Jn the dining-room, a radio set can be | built very easily into a buffet (Fig. 7). 'Qne of the type shown is especially ‘adaptable. In the space below the panel an inside door can be fitted to divide the ‘interior as a battery compartment (see upper illustration). The loudspeaker can be mounted be- hind the door on the other side of the GLASS REMOVED AND | FABRIC SUBSTITUTED | : a we ’ LS —= h oes | —S> i a 7 LOOP AERIAL ON BACK OF BUFFET A buffet with a loop aerial mounted on the back makes an excellent radio cabinet buffet. Remove the glass from this door, if there is any, and substitute a sheet of some thin fabric of a color to correspond with the woodwork. Otherwise make a removable framework to go just inside the door and cover it with silk to match the room’s color scheme. With an installation of this kind, a large loop can be concealed behind the buffet, but a great deal of its effectiveness will depend upon the direction in which it points in relation to the direction of the stations from which reception is desired. If the chief stations all lie in a single general direction, the buffet can be so set that the edge of the loop points in that direction. The loop may be bell wire fastened to the back with insulated staples. The exact number of turns necessary is determined by the diameter of the loop, but will prob- ably range between seven and 15. Unit sets, mounted on baseboards as described, can be mounted in innumerable pieces of furniture and odd corners about the house, Corners of closets, medicine cabinets, bookcases, and sewing-tables, all lend themselves readily for this pur- pose. A compartment of a sectional bookcase makes an exceptionally fine case for a set. | | | and you have re- markable added power speeds no matter how fast you're driving. No clashing; no stripping. The Only 2-Speed integral part of the car, with the same standardized precision —— | — ; automotive engineering design and_ operation. Gives you TWO NOISELESS HIGH SPEEDS— 4 four forward and two reverse. Nothing else like the / RUCKSTELL AXLE. Not an auxiliary transmis- / sion; not an ‘‘accessory.” go through any roads, Climb practically all hills on ‘‘high’’—pass the other fellow always. Throttle down to 3 traffic; wonderful flex- OOxPS : i nk —— a eae Install a RUCKSTELL AXLE and Go Anywhere! Get a light car and have the dealer install the famous Ruckstell Axle— then you'll get a new thrill out of motor car ownership. Go anywhere— to the Lakes, the Mountains—cross-country on the Dixie, Lincoln or Jefferson Highways—or through heavy, muddy roads. All look alike to the Ruckstell equipped car! s Power and Speed in ONE You'll have 55% more power with the Ruckstell. If you want greater speed you can have 20% more. The mere shift of a handy lever transforms a light car into a ‘“‘Power” or “‘Speed’’ car at the will of the driver, Never before has it been possible to combine WO DIRECT OPPOSITES in ONE. The Ruckstell solves the problem. Nearly 100,- 000 now in use. 100% satisfaction guaran- teed; every owner a booster. Axle in the World Installed in rear housing; becomes an / FREE Demonstration / Free See your nearest dealer in light cars. He ue This coupon will gladly demonstrate the wonderful good for Free TWO-PURPOSE PERFORMANCE of 74 Demonstration the Ruckstell Axle. Or, write us for / at nearest dealer, Free Booklet, Prices, etc. Address y 0 for Free Booklet. our nearest office, Dept. 19-A 7 (Dept. 19-A) r RUCKSTELL SALES 7 Name...... & MFG. co. y i NEW YORK CITY 7 KANSAS CITY, MO. y Me OO OT eC er L SAN FRANCISCO, CAL. / MONTREAL and i ee TORONTO, CANADA / ERWELOS CAE Sista: 6,0: 'x: avaralsvc'ate ecg Wanalnens / 2$4.00 Adding Machine The Gilson Adder will do your figuring H easily, quickly and with absolute ac- Capacity 109,999,999 to multiplies and divides and automatically carries from one column to the next. thi] Made with aluminum case and_ steel parts, size 314''x6’"xl¢”’. Written Two-Year Guarantee. Catalogue Free. Price, postpaid, $4.00. Your money back if you are not satisfied. A Tool ory It adds, subtracts, get when you geta Catalog free 508 Columbia St., Dayton, 0. that combines strength and convenienc —that gives the utmost tervice under all con- ditions—that is the kind you Gerstner H. GERSTNER & SONS Giison Sliae Rule Co., Niles, Mich. GO cont wo f Learn to Make Show Cards—by Miller Mail Method in 60 by days—no experience needed. We establish you in your own shop, , Show Cards any locality, worth $60 weekly, up; furnish all material and plan to secure orders learned, profitable business. Cost low—terms easv. Illustrated matter ard terms FKEE. EMPIRE INSTITUTE, 1476 Broadway, New York from local merchants to do right at home, evenings, if desired. Get into this fascinating, easily

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An Easy Way to Learn PHARMACY AT HOME Graduate pharmacists are always in demand. The work is interesting and pleasant and salaries are good. Many young men open drug stores of their own and become independent. There’s an easy way to learn pharmacy right in your own home in spare time, without losing a day or a dollar from your present work. The International Correspondence Schools course in Pharmacy supplies the knowledge which it will be necessary for you to have in order that you may pass your State Board Examination. Just mark and mail the coupon printed below to the International Correspon- dence Schools, Box 7€04D Scranton, Pa., and full particulars about the Pharmacy Course or any other work of your choicc will come speeding to you by return mail. o—— — — — TEAR OUT HERE INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7604-D, Scranton, Penna. Without cost or obligation on my part, please send me full particulars about the subject before which I have marked an X in the list below:— TECHNICAL AND INDUSTRIAL COURSES [IPHARMACY , } Civil Engineer Chemistry "}Surveying and Mapping “jAutomobile Work []Mine Foreman ot ®ngineer JAgriculture and Poultry (J Steam Engineering -)Mathematics Electrical Engineering Electrician Mechanical Engineer Mechanical Draftsman Machine Shop Practice [JConcrete Builder Railroad Positions LJStructural Engineer BUSINESS TRAINING COURSES [)Salesmanship [)Business Management jAdvertising [ Industrial Management -) Better Letters JPersonnel Organization Foreign Trace { Traffic Management _JStenography and Typing L)Business Law |) Business English _JBanking and Banking Law { JCivil Service JAccountancy (including C.P.A.) _}Railway Mail Clerk Nicholson Cost Accounting — ee ee ee ee -]Gas Engine Operating -}Airplane Engines [j Radio 7} Architect _jContractor and Builder _j Architectural Draftsman

ULL JCommon School Subjects] Bookkeeping JPrivate Secretary Business Spanish | JHigh School Subjects Illustrating

OD French

| Oe Occupation Persons residing in Canada should rend this coupon to the | Limiteds | international Correspondence Schools Canadian, Montreal, Canada,

Easyto Draw Cartoons When Shown in the RIGHT WAY Some of the cleverest cartoonists and comic learned how_to draw in their spare time by following

artists | Cartoonirt Evans’ Simple and Easy to Learn Method | and are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans sce it you have ability and receive the Portfolio of Cartoons and full detai!s about the course. It is not expensive. THE W. L. EVANS SCHOCL OF CARTOONING 825 Leader Building d, Chio Attachments Convert Breast Drill into Small Lathe STANDARD 18-in. bench drill is converted into a simple lathe for small work by the addition of the at- tachments illustrated. The lathe will serve for either wood or metal turning when the work is light and within the range of hand tools. The same attach-

BENCH

GROOVED PULLEY REPLACES CRANK The attachments for using a breast drill as a bench lathe are shown above. The same attachments form the wall drill illustrated at the left. The details appear

below . a 176 DIA., a 2 2 : ‘ i : Ge > # SSETSCREW BOLT 2 CLAMPS ALIKE EXCEPT | ENDS BORED TO SUIT DRILL

PLATE CENTER 23 i:

44 TO FIT BREAST | mat DRILL + A) + & : lo

TOOL REST a CHUCK 3 SETSCREW ments also are used to provide a wall drill. The flexibility of this combination tool

| HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

for electrical work, building model ma- | chinery, and very light shop work, is | obvious. Another advantage is that it may be attached to the edge of any heavy

You will be astonished to see how quickly you master this wonderful instrument — the Buescher Saxophone— that has already in a few years taken its place as the most beautiful and versatile instrument of all popular orchestras. With the aid of the first three lessons, whicharesent(upon request) without charge with each new Saxophone, the scale can be mastered in an hour; in a few weeks you can be playing popular music. You can even take your place in a band or orchestra within 90 days, if you so desire. The man or woman, boy or girl, who can play the Saxophone, finds a cordial welcome everywhere. For school, lodge, church or home entertainment the Saxophone has no equal. BUESCHE2 ————_—S—ri‘ (;&e True-Tone Saxophone No other instrument has ever won such universal popularity in so short a time because no other in- strument has that rich appealing tone and is produc- tive of so many surprising orchestral effects. Easy to Play—Easy to Pay Why not try a Buescher Saxophone in your home without obligation? Easy terms of payment can be arranged—play while you pay. Free Saxophone Book Just send the coupon or a post card for your copy. Mention the instrument in which you are interested and complete catalog will be mailed. (31) Buescher Band Instrument Co. Everything in Band and Orchestra Instruments 112 Buescher Block Elkhart, Indiana CEC RSSTSRASSTAESS SRS SSRE SESE Reese Basser Buescher Band Instrument Co., 112 Buescher Block, Elkhart, Ing Gen: lemen: I am interested in the instrument checked below:

Saxophone ....... Cornet.......... Trombone........ Trumpet...... (Mention any other instrument interested in) OE PIIIG ccicinnn sivas -ccvckcaniciaveseiasacvennttinniconnaimmmaannasian Town State « Camping and Campsite Manual Compiled by the American Automobile Association

The Manual has a list of more than 1200 automobile campsites in all sections of the country, with location, description of equip- ment, and other details of interest to motor campers. Price, Fifty Cents Popular Science Monthly 225 West 29th Street, New York, N. Y- FOOTBALL FOR EVERYBODY Every fan, old or young, likes The Gregg Football Game. A perfect representation of college football, sls a the new 1924 rules. Not a toy using spinners, cards OT dice, but a new game of wits and strategy played sa table with a small football field and two teams. ach player is his own Quarterback and directs his team as!0 real football. At your sporting goods dealer or post pale for $2.50. Write for illustrated folder. ALBERT A. GREGG CO., Dept. S, West Jefferson, Ohio

<a “ee |

=—=s)\F

Ree wecowem eA © 8S envoOrese

Page 97

onished kly you nderful — the phone— dy ina ts place iful and of all Vith the lessons, equest) th each 1€ scale an hour; * music. ‘chestra lay the ywhere. ainment niversal ther in- produc- Pay ur home t can be ok ur copy. terested (31) t Co. nents Indiana Seaerener ion n 1200 of the equip- » motor thly im. ¥. —<$$—$——_ opY ‘ootball all, with cards or ed ona _ Each am asin yost paid

n, Ohio ———— HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 95

THE 21 JEWEL. Santa Re Without one penny of advance payment, let us place in your hands to see, to examine, to inspect, to ad- mire, to approve, a real masterpiece in watch crea- tion. A watch which passes the most rigid inspection and measures up to the exacting requirements of the Great Santa Fe Railway System, and other great American trunk lines. The one Standard Watch Guaranteed for a Life-time of Satisfactory Service, not only by the Santa Fe Watch Co., but by the Great Illinois-Springfield Watch Factory. Page 12 of Our Watch Book Is cf Special Interest to You Ask for our Watch Book free—then select the Watch you would like to see, either the famous Santa Fe Special or the 6-position Bunn Special. and let us explain our easy payment plan and send the watch express prepaid for you to examine. No Money Down. Remember—No money down—easy payments buys a master timepiece—a 21 Jewel guaranteed for a lifetime at about half the price you pay for a similar watch oi other makes. No money down—a wonderful offer. SANTA FE WATCH CO. 889 Thomas Bldg. Topeka, Kansas (Home of the Great Santa Fe Railway) =e ee ee ee ee eee ee ee ee ee ee ee ee Santa Fe Watch Co., 880 Thomas Bldg., Topeka, Kan. _ Please send prepaid and without obligation your Vaich Book free, explaining your ‘‘No Moncey Down" Offer on the Santa Fe Special Watch.

Use ~ Pre 75" C-¢= | DURHAM | # Variable Grid Leak At dealers, or postpaid w—Durham & Co., 1936 — St., Phila. Motorcycle Bargains SAVE 25% to 65% oa Slightly Used and Rebull Horeycles, Ace, Indian, Fr sa arley-Davidson, Cleveland, Side me ohnson Motor Wheels, Evans nig Cycles, Bicycles. - Send for . Bargain Bulletin and bundris ins Message, listing paiae

of 1 . ft : . supplies, fe /argains in used, rebuilt and new machines, Ccessories, etc. AMERICAN MOT Deot.826 2047 W. Chicage Aves en Ci CHICAGO

- n 5 Sections the People and objects miles away just like ps ve cose, see Moon and Stars as Se bse fal sd id before. Brass bound, SEND NO MONEY Big 3 toot Telescope en away, see moun . an Attachments for Breast Drill (Continued from page 94) workbench and requires no special wall supports or stand. A grooved pulley is substituted for the drill crank. A small electric motor, such as a sewing machine motor, provides the power, or the pulley can be belted to the flywheel of a treadle. A round shaft or pipe forms the main frame or bed of the machine. Two forged arms, made as shown, support the breast drill. The next member is a forged bracket with a faceplate that supports the frame when used vertically as a drill press, and holds the adjustable toolrest when the device is used as a lathe. The tailstock is fitted with a sliding shaft and tapered center. A plate is substituted for the center when the machine is turned up to serve as a drill. A lever and link operate the sliding shaft in the tailstock. The drill chuck is replaced, when necessary, with a simple chuck to hold paris 2p to 3 in. in diameter. All the parts are fastened to the frame or bed with setscrews and can be ad- justed to suit requirements. The breast drill can be removed and the crank re- placed in a few minutes to restore it to its ordinary use.—G. L.

Cushioning Kitchen Faucets with Crutch Rubbers FTER several china dishes had been chipped or broken by being knocked against the sink faucets, I placed or- dinary crutch rubbers over the ends of the taps to prevent further accidents. The rubbers were obtained at a five and ten cent store for 10 cents. A hole was cut in the bottom of each the same size as the opening in the end of the fau- cet. Whenever desired, the rubber bump- ers can be re- moved for cleaning. Cheap as they are, they do not look out of place in the most up-to-date kitchen. If crutch rubbers are not available, ordinary rubber stoppers, obtainable at any drug store, can be used if a smooth hole is drilled through each.—D. V. H.

The rubber prevents breaking china

Adding a Spring to Pliers PIECE of flat spring steel riveted to pliers handles as shown is a con- venience for cer- : tain kinds of work. The ten- sion of the spring ’ keeps the jaws of the pliers normally open and therefore allows a ready use of the { i ‘RIVETS

Your Choice 75c a Week ies ee a We have cut the price one-half

No matter what your occupation, one of the home study sets listed below will quickly fit you for a better job and bigger pay. Any set you select will be sent for seven days’ examination, and if you decide to buy you may pay the rock bottom price at the rate of only 75c a week. But you must act now! The rising cost of paper and binding materials won’t permit us to continue the present low prices much longer. These books are the work of recognized author- ities. They are written in plain, easily understood language, by recognized authorities, and contain hundreds of photographs, diagrams, tables, etc., that make difficult points as simple as A-B-C. Hand- somely and durably bound in half or full morocco leather (except as noted), and stamped in gold. Pa -Raising Books tly Reduced Prices Business Management, 8 vols., 2500 pages, 1000 pictures. Was $52.50..........Now $29.80 Carpentry and Contracting, 5 volumes, 2138 pages,1000 pictures. Was $37.50,Now 19.80 Civil Engineering, 9 volumes, 3900 pages, 3000 pictures. as $67.50 34.80 Electrical Engineering, 8 volumes, 3800 pages, 2600 pictures. Was $60.00 ....Now 29.80 Automobile Engineering, 6 volumes, 2600 pages, 2000 pictures. Was $45.00 ....Now 21.80 Machine Shop Practice, 6 volumes, 2300 pages, 2500 pictures. Was $45.00 ....Now 21.80 Steam and Gas Engineering, 7 volumes, 3300 pages,2500 pictures. Was $52.50 .Now 24.80 Law and Practice (with reading gee as Now 49.80 Fire Prevention and Insurance, 4 vols., 1500 pages, 600 pictures. Was $30.00, Now 14.80 Telephony and Telegraphy, 4 volumes, 1728 pages, 2000 pictures. Was $30.00 -_— Sanitation, Heating and Ventilating, 4 volumes, 1454 pages, 1400 pictures. Was $30.00 Now 14.80 Drawing, 4 volumes, 1578 pages, 1000 pic- tures, blue prints, etc. Was $30.00. .. Now 14.80 Send No Mone Shipped for 7 days’ Tria Yes, we'll gladly ship any set right to your home or office upon your simple request. Pay only ship- ping charges when the books arrive. Don’t send a penny until after you have used them seven days, then remit only $2.80 or return them at our expense. Pay balance at the rate of $3.00 a month—75c a week. . Act now—while these splendid books are being offered at 20% to 50% less than regular prices. This offer is open to every person within the boundaries of the U. S. and Canada. Grasp your opportunity— fill in and mail the coupon now. American Technical Society, Dept. XC-20, Chicago 4 American Technical Society, Dept. XC-20, Chicago, 0&2 1

Please send me set of for 7 days’ examination, shipping charges collect. i I will examine the books thoroughly and, if satistied, J will send $2.80 within 7 days and $3.00 each month, i until I have paid the special price of . If I decide not to keep the books, I will notify you at J once and hold them subject to your order. Title not 1 to pass to me until the set is fully paid for.

Address A. C. Paime: eased. SPECIAL OFFER. Send just your name. arrival pay postman $1.85 plus few cents st n Guaranteed or money ke

tool.—JACK PRINTZ. Employed by er aoe v4 = = of oe ee ow owe ow ow oe oe oe oe ee On noetage,

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ATKINS Shown above is Atkins No. 10 Hack Saw, fitted with Atkins ‘‘Non-Breakable"’’ Blade. Has hard rubber handle, “easy grip'’ pattern. Steel frame is adjustable to 8, 9, 10, 11 and 12- inch blades. A Perfect Saw for Every Purpose For every man who buys or uses saws, there's an Atkins saw to do the work easier, quicker and better. Here are a few of many popular Atkins saws. If your dealer hasn't the ones you want—write us, and we will see that you are supplied. It’s a pleasure to own the finest saw made in quality, workmanship and finish. Genu- ine SILVER STEEL BLADE, Ship point, 26-inch length, five gauges taper ground. MIRROR POLISH. Solid ROSEWOOD HANDLE, Improved Perfection Pattern. Skew or straight back. There are other Atkins hand saws for every requirement. “Saw Sense”’ shows them. JUNIOR MECHANIC HAND SAW A new saw for the Boy Scout and radio mechanic. Handy for home use, too. Made 20 in. long, skew or straight back, nine points, taper ground, highly polished; beech handle, mission stained. A very convenient, high grade saw at a most moderate price. ‘No.3 NEST This set includes 12-inch keyhole blade, 14-inch compass blade and 18-inch special nail-cutting blade, interchangeable in ad- justable handle. “Saws in the Shop” shows Atkins metal- cutting saws and contains many time and money-saving suggestions. “Saw Sense’ shows our wood-cutting saws and tells how to file and care for saws, and gives dozens of helpful facts on building. “Saws on the Farm” shows the most complete line of saws for use on the farm. IS) Write us today for booklet you want. E. C. ATKINS & CO., INC. Makers of ‘‘Silver Steel’’ Saws and Tools Dept. D-20 Indianapolis, Ind. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY The Home Shipshape | THE various small repairs necessary in Shipshape Home Toolkit | keeping any home shipshape can be made with the least inconvenience and loss of time if the necessary tools, nails, screws, and other small supplies are kept together in a toolbox. The one illustrated has proved particularly useful for this purpose. Carried around from place to place, it saves needless steps back to the workshop to get forgotten materials and tools. The design of this box arose from the fact that I use cigar boxes to store my supplies and have accu- mulated several shelves full of them in the course of time. Some of the boxes are subdivided into four parts for assort- ments of screws, tacks, and the like. Sandpaper, broken glass for scraping, spools of wire, fric- tion tape and similar material occupy one or more boxes. Each box is lettered on the front to indicate —— The toolkit and the ; cover, which is optional the nature of its individual contents. When I start out to do a job anywhere in the house, I slip the cigar boxes con- taining the necessary supplies into the bottom part of the box. As I keep all the necessary tools in the top part, I am away without any bother. For the beginner at home-workshopping, to coin a word, the box will contain all his tools for a considerable time and will remain a useful adjunct even when he graduates to a toolchest of his own. The box should be made of light ma- terial, 14 in. or 5% in. thick, except the center board, which is 34 in. A metal carrying handle, from the hardware store, is attached to the middle of the top of this board. To make a really workman- like job, the cigar boxes should be taken ‘lacked or varnished. A screweye is use4 apart, planed, reassembled and _ she. in the middle of the front of each cigy box as a pull. The toolbox may be made and usy without a cover, but the cover will found useful in keeping out dust and dir and in allowing the contents to be locke; up by simply snapping a padlock throug) the handle when the cover is on. For the benefit of the beginners doing repairs around the house, let m } say a few words on tools, br yop Don’t try to get along with only one screwdriver. Buy; large and a small one and say time and patience and broke, tools and screws. An awl that is sharp pointed and sturdy enough to stand hammeriy on the end is very usefil around the house in making holes for the small screws used in putting up shade small brackets and the like. When you get used to doing a fer odds and ends, branch out and try the bigger jobs of making new thing, A ratchet bitbrace with a few bits, 9-in. smoothing plane, a good oilstone, and a saw enable you to do many jobs. But above all, buy good tools. Have: place for them and keep them clean and sharp.—STANLEY W. BLANCHARD. Havinc had tw How to Lay coverings of line Linoleum leum on our kitchen floor, we decided to make the next application so permanett that it would last for years to come Previously the linoleum was in narro¥§ strips with seams that allowed the mo) water to penetrate and rot it. To avoid this, we bought linoleum 12 ft. wide. As the kitchen is 11 ft. wide, I used4 pair of tinner’s snips, the best thing in the world to cut linoleum with, and trimmed off 1 ft. from one side. Afte covering the floor with building pape, without which no linoleum should be laid, we rolled the linoleum over the floor, putting down a 16-ft. length with ™ seams whatever. Our decorator advised us to give th§ linoleum several coats of floor wax, whith we did. The wax is put on about 2 54. yds. at a time and then rubbed down with a soft rag. This allows the surface to be kept always fresh and free from spots. In my experience, inlaid linoleum should be cut at least 1 in. smaller that the floor it is to cover to allow for the expansion. After the linoleum has & panded and set, the door openings should be covered with brass strips and tacked well down.—Harry C. MOSHER.

Page 99

and = shel. Ye is used each cigar and used er will be t and dirt be locked k through 1 yeginner at se, let m tools. along with r. Buya e and save nd broken n awl that nd sturdy 1ammering ary useful in making Il screws 1p shades, ickets and you get oing a few 1d ends, ut and try ew things ew bits, 3 stone, and jobs. is. Havea . clean and RD. had two ; of line our kitchen decided to permanent . to come, in narror & d the mop To avoid wide. o, I used’ t thing in with, and ide. After ing papef, uld be laid, the floor, h with no o give the wax, which bout 2 84. down with rface to be n spots. linoleum naller than yw for the m has ex ngs should ind tacked ER.

Discarded Furniture Converted into Ornamental Welsh Dresser N OLD-TIME dresser with a mirror held _ be- tween lyre-shaped brackets formed the base for the Welsh dresser il- lustrated. The top was removed and a section was cut from an old bedstead to make the upper part of the dresser. A narrow ledge for plates was fas- tened across the center of the top board and the brackets that formerly held the mirror were used as the ornamental side pieces of the top. The tin pulls were removed and antique bronze handles substituted. . The whole then was enameled black and orna- mented with flowers copied from a Dres- den plate—M. L. CHERRY.

The remodeled dresser

Special Table Lightens Labor of Bathing Small Baby : io first step in building the baby’s bath table illustrated is to obtain a white enamel tub with a rolled edge. Measuring from that, the top is made as for an ordinary kitchen table. The outline of the tub opening then is laid off and diagonal braces put into place underneath, where they will not obstruct the table hole. The hole is sawed and around the rim soft pine boards 4% by 1% in. are mitered glue and brads, the brads being set in CORNER BRACES ——

Baby’s bath table with rims to pre- vent water from spilling on the floor 80 as to fit under the rolled rim. Next, a %-in. half-round beading is tacked and glued all around the outer edge of the table. The object of these two rims is to retain water splashed out of the tub. | Ball-bearing casters are provided so that the table rolls almost as easily as a aby carriage, and in any direction.

Several coats of white paint finish the job. A table of this kind has been in use for Several months, and the baby’s mother Says she doesn’t know how people ever Manage to bathe babies without such a | table—R. W. ER. Laibesibiciisiacnate

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY plifying The new All-American Long Wave Radio Fre- quency Transformer, in its nickeled shield at $6, is one of the finest am- instruments _ made at any price.

A MASTER INSTRUMENT for the Super Heterodyne Designed to perform in all long wave radio frequency circuits as instrumental master- pieces in the hands of artists, each of these new All-Americans actually “plays its part” in perfect harmony with other fine radio in- struments that compose the “ensemble.” Here are the facts you should know to judge the supremacy of the All-American: (I) High amplification, without distortion, of any transformer on the market; for wave lengths 4,000 to 20,000 meters. (2) Quiet in operation; shielded to prevent inter-stage coupling or

reaction. (3) Stable; free from any tendency to oscillate. (4) Windings specially designed to eliminate capacity; properly treated to exclude humidity. (5) Every transformer “circuit-tested” for accuracy and precision to insure uniformity and highest efficiency. (6) A splendidly made long wave transformer thoroughly tested and approved by Popular Science Institute of Standards. guaranteed. All the better dealers recommend the All-American. Built the industry: RAULAND MFG. CO. 2667 Coyne Street, Chicago . ALL-AWi RICAN by pioneers in AMPLIFYING TRANSFORMERS Largest Selling Transformers in the World Fully

and fastened with | deep to allow for trimming the boards.

_<—< Write for

eA. NEW twenty-four page booklet will be sent, gratis, to those interested in build- ing their own receiving sets. A simplified method of con- struction is described. IlI- lustrations and diagrams. On Request EISEMANN MAGNETO CORPORATION William N. Shaw, President | 165 Broadway, New York

PARKS Cabinet Shop Special $225 with all attachments and motor fast and true. The woodworker ever built. 4-in, jointer and_ borer. choose from ments: band saw; lathe; and motor.

PA

these extra shaper; Send for Bulletin C-S and complete Parks catalog. The Parks Ball Bearing Machine Company 1547 Knowlton St., Cincinnati, O. Canadian Factory: 209 Notre Dame East, Montreal, Can, For your home shop!

ERE’S an all-round woodworker for the small shop. Sturdy, biggest little Saw table has 8-in. rip and cross-cut saw, and You can attach- sander;

Page 100

“Red Devil’ Tools Pay for Themselves Over and Over Again HOUGH slightly higher in price, they give added service and value out of all proportion to their cost. An investment in ‘‘Red Devil’’ Tools is money well spent. “Red Devil” Glass Cutters The only cutters made with hand honed wheels—cut clean and sharp, with the lightest pressure. 40 styles. No. 024, for home glazing jobs, 20c each. “Red Devil” Chain Drills Makes easy work of drilling iron or steel, the truck frame, engine cyl- inder, angle irons and for all-around drilling purposes. It’s automatic and portable. No. 2018, $4.95 each. “Red Devil’ Hack Saws For cutting sheet metal, pipe, tub- ing, cables, steel rods, and bolts, light structural steel, etc. No. 1048, shown here, adjustable for 8 to 12 inch blades, $1.00 ‘““Red Devil’’ Tools are sold by all dealers —-if not in stock send dealer’s name and order from us. Mechanic’s tool booklet free SMITH & HEMENWAY CO., Inc. Manufacturers of ‘‘Red Devil‘? Tools 264 Broadway New York, N. Y. ‘“Red Devil’’ Pliers Known and used the world over. Drop forged from tool steel—made Ps in 100 styles, for ‘ every need. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY | Neat Radio Stand Cheaply Made from Old Bureau RADIO cabinet or stand of fine ap- pearance often can be obtained at small cost by the simple expedient of remodeling a piece of discarded or second- hand furniture to serve the purpose. If your own attic or storeroom has no old desk, wardrobe, bureau, or dresser that will do, visit several dealers in second- hand furniture and pick out what you think will work up to best ad- vantage. Old music cabinets, phonograph record cabinets and desks of various types are well adapt- ed for holding radio sets and batteries. In my own case I used an old bureau of the 1860 style. Removing the top, I sawed off the case just under the top drawer and put the top on there. The second drawer, which was now the top drawer, was partitioned off for head sets and accessories. Two lower drawers were removed en- tirely, as well as the division boards. ‘ach side of the front then was closed by using part of a drawer front. The space between was left open for knee room. Shelves were put in behind the front boards to hold both the A and B batteries, one on each side. The only cost was for sandpaper and varnish. At the back is a switchboard.—J. R. KoontTz?, Bremen, Ind. A roomy stand for a radio set Graceful Wrought-Iron Lamp (Continued from page 74) work will not be square when finished. The rivets securing the two smaller legs to the pipe should be staggered at least 1 in. so that they will pass each other in the center of the pipe. The bracket holding the lamp socket is made adjustable for height by having the 3¢-in. pipe pass through drilled holes in the top and bottom members at such points that the curled end of the top member will press against it as a spring. This tension will hold the bracket in any position desired. There is probably one other place where the amateur craftsman may spoil the looks of the project if he is not careful. This is in drilling and tapping the bracket for the attachment of the light socket so that it hangs parallel to the spindle. The kind of shade, the method of attaching, and the finish of the lamp are more or less a matter of individual choice. A coat of black enamel was the finish used on the one photographed for this article. The shade is of parchment fastened to a frame that fits the end of | the socket. The wire of this lamp, as will be noticed, was run through the pipe, but unless the lamp is to be used in connection with a floor socket, it would be better not to do so, as it is a somewhat difficult under- taking on account of the rivets through the lower pipe. as a striking plate.—S. B. Muffling a Punching-Rag Platform in the Cellar wo a father almost always is glad to buy his son a punching-bag, there is usually no place to hang it except in the cellar, and then, if the platform js fastened directly to the ceiling, the whole house gets a shaking up whenever the bag How the striking bag is mounted to avoid noise and vibration in upstairs rooms is in use. To overcome this vibration, the striking-bag platform may be mounted as shown on the iron posts or brick or con- crete piers that support the main girder under the first-floor beams. This arrange- ment also allows the platform to be ad- justed in height.—F. S. Root. How to Make Concealed Catches for Furniture Doors Rais. friction catches, so popular with both professional and amateur cab- inetmakers for small doors, such as on | radio, phonograph, and medicine cabinets, are not always easily obtained in the size needed. In that case they may be con- | structed from material usually to be found in the miscellaneous box. The one illustrated at the left is made from 1 ball bearing, 2 washers just large enough so that a ball will not quite slip GALL TOP CORNER BEARING. OF DOOR» eg ’ / | BARBS| SPRING l DETAIL OF PLATE DETAIL OF WASHER When commercial catches are not available, substitutes may be made, in either of the two ways shown, with little difficulty through the hole in the center, 4 screws, and a brass coilspring slightly smaller in diameter than the ball. In the catch at the right a brass or copper tube, large enough to take in freely the ball bearing and spring, is swaged or hammered on one end to pro- duce a lip, which projects on the inside and prevents the ball from coming out. A few barbs are cut on the outside of the tube with a sharp chisel to hold it in the hole, which is bored in the top edges of the door. A square plate or washer let in flush with the surface of the wood, is used three the 1 TI of m Dr. effec amot The food best hum

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lad dag, -ept n is 10le bag id ns ‘ion, nted con- rder nge- ad- hes with cab- 5 on nets, | size con- » be nade arge slip b. Put on like Plaster 4 |{ Wears like Iron W \-waterproof pfireproof resilient a $C - Die ee AR fe A composition material easily applied in piastic & 2 form over practically any kind of floor. Laid M about % inch thick. Imperial Floor does not ‘4 crack, peel, or come loose from foundation. A d continuous, fine grained, smooth, non-slipping surface. No crevices to gather grease, dirt, dust, [# ™ disease germs Or moisture. # * Ideal Floor for Kitchen, Pantry, Bath Room, §& " taundry, Porch, Garage, Restaurant, Theater, > M Hotel, Factory, ce Building, Railroad Station, } "| Hospital—wherever a beautiful substantial floor js desired. Several practical colors. Full in- 7% formation and sample FREE of your first and § second choice of color. ? G Imperial Floor Co., 325-327 Halstead St., Rochester N.Y. ? } s A Success for 15 Years iazenrmeeta The American Home Diet E. V. McCollum and N. Simmonds wat to eat and why. Scien- tifically-worked-out menus for three meals a day for every day in the year. This book is based on the results of many years of experimenting by Dr. McCollum to determine the effects of different foods and different amounts of food on animal tissue. The menus are planned to give the food in proper proportions for the best growth and health of the human body. Price $3.50 PoPpULAR SCIENCE MONTHLY 225 W. 39th Street, New York, N. Y. U. S. Railway Mail Clerks Needed! Big opportunity. Salaries $1600 to $2300 a year. Short -hours. Liberal vacations. Steady work. ) A chance to travel and see the country. Examinations not diffi- cult. Common school education all you need as ground-work. Write to-day for 48-page FREE BOOK- LET on CIVIL SERVICE. It tells you how you can get a posi- tion with the U. S. Government. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7607-D, Scranton, Penna. “WONDER” COLD PIPE, TUBING & BAR BENDERS HAND and MOTOR OPERATED 14 Sizes of Machines \ bain t ae bend pipe our AN \ ’ 1’ pipe 5 cents 4’ pipe 25 cents i Dag 2"* pipe 10 cents 6"’ pipe 60 cents AWW 8”’ pipe $1.00 Send for Catalogue. AMERICAN PIPE BENDING MACHINE CO. S1 Peari St. Boston, Mass. Tool Cases for Machinists, Car- penters and Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered. Ask for booklet. po Sit —wer ‘*Built for Service’’ The Pilliod Lumber Co., Swanton, Ohio HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Assembling a Motor Generator Unit for Charging Batteries By Arthur M. Vinje os charging the storage A battery of my radio set, I assembled the motor- generator unit illustrated. I happened to have the motor, but there is no reason why the motor of a washing machine could not be used, provided it is replaced not later than Sunday evening each week in its proper place on the wash- ing machine. Otherwise you may hear from the boss! The generator came from a dealer in used auto parts for $6. The ammeter, The charging outfit, with switch panel and am- meter, connected with a radio storage battery from the same source, cost 75 cents. Belt, pulley and switch were found in a box of odd parts accumulated from past adven- tures in my home workshop. The instru- ment board is a discarded radio panel. The actual arrangement might have to be varied to suit individual needs. The method I adopted was to arrange the battery leads to go to the center posts of a double throw switch and the wires from the generator to the lower posts. Leads from the upper posts go.to the radio set, so that it is unnecessary to move the battery for charging. The generator set maintains a uniform charging rate of 314 amperes, and could be used for charging any 6-volt battery. The fact that the generator is driven a little below normal speed explains why this amperage is so low. In experiment- ing, I found that the generator developed about 14 amperes and seriously over- heated when connected directly with the motor, the speed of which is 1750 r.p.m. Since the photograph was taken, I have changed to a gear drive and raised the charging rate to 5 amperes. Hollow Block Holds Firewood Upright for Splitting 5 eeneta split- ting fire- wood, I find the block illustrated is a great aid. The piece to be split is stood up- right in the hol- low center of the block, which prevents it from tipping over. In hollowing the block, I first split it into halves, then chopped out the center and nailed iron hoops around to join the two halves together again. An 8-in. square piece of sheet iron is nailed on each side of the block to hold the splitting ax.— P. V. Stump, Oxnard, Calif. sat | Wifs fj No Wise Man Goes Through This Twice NE session on the road with something loose in the bus and a flock of trick wrenches that won’t fit where they’re needed, is enough for any sen- sibleman. Next time anything happens there’s a Snap-on Kit under the seat that’ll handle any nut or bolt on the car, whether out in the open or around a corner. But there’s seldom any next time when you have Snap-ons around, for it’s so easy to keep things tightened up as they should be, that they don’t loosen up at awkward times. Your dealer can select a Snap-on Kit for any make of car. See him soon. If he hasn’t got them yet, write us and tell us what you’re driving. We'll tell you just what a Kit for the car will cost, and it'll be less than you think it will be. A Handful Completely Services Any Car @ Snap-on Socket Wrenches MOTOR TOOL SPECIALTY 14 E. Jackson Blvd., CHICAGO Gentlemen: Please send me full particulars about Snap-on Kit | oe oe EO re ee car. (If interested in Master Mechanic’s Kit, check here...........0e ee eeeeeeees ) I buy tools from......sccccccccccccccevececccovovors INGE Sicicsicciccsddncacnevendeocdacsonsessemeouneees

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100 KESTER METAL MENDER It’s a Genuine Solder Simple to Use Requires Only Heat HOMETINKERS Need will develop from roof to cellar HOUSEWIVES Asimple,practical mender for metal ware in the home MOTORISTS For repairs on the road or at home SCHOOL BOYS For ding and maki toys FARMERS For use in dairy, garage, a i No 1S household and eme. gency repairs SPORTSMEN Keep a can in your k= you'll have need for it If your neighborhood dealer cannot supply you send us= Chicago Solder Company 4220 Wrightwood Ave., Chicago, Ill. Gentlemen: Send me one can Kester Metal Mender for it 25ci ani tone Postpaid onywhere in U.S.A. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY IOFFER YOU $200 A WEEK °*;* We want men and women in aed community to demonstrate and take orders for Comer All-Weather Coats. wc apne enables you toearn $200a week and a Buick Fouring Car. No collecting or delivering. No experience needed. Mail the coupon now for full details. The Comer Mfg.Co., Dept.BO-48 Dayton, 0. Just Mall This NOW cecesccccccceccccecseseces: The Comer Mfg. Co., Dept. BO-48 Dayton, O. Without obligating mein any way please tell me how I can make $200 a week and get a Buick Touring Car. TOURING CAR Name Mdapess. Print or write plainly Making Decorative Candle Sconces for Wall Ornaments PLEASANT evening or two may be spent in the home workshop making and decorating a pair of sconces or wall candlesticks. These are popular just now and add a decorative note to the furnishings of any room. The sconce il- lustrated is easily made, yet it is orna- mental when holding a_bright-colored candle—one that matches the color scheme of the room in which it is placed. Two pieces of wood, a furniture knob, a chair round or wooden dowel %% in. in diameter, and a 4 by 6 in. piece of thin copper, are al] the materials needed. The holder for the candle is 144 by 1% by 414 in. with a 114-in. hole in one end. Front and side views of an easily made, neat, and attractive candle holder Notice that the sides of the piece are placed at an angle of 45 degrees to the back. If a lathe is handy, turn a small knob, to be fastened to the lower end of the holder. If no lathe is at hand, a 134- in. furniture knob, obtainable at any hardware store, may be used instead. Fasten it to the end of holder by gluing. The sconce should be finished to har- monize with the furnishings of the room. Then fasten to the back a highly polished piece of copper, 6 in. long and shaped as indicated, using small brass round-head screws or 3-in. escutcheon pins. A full size square or round candle may be put into the sconce, but the arrange- ment looks particularly well when the candle is burnt down a bit.— KENNETH R. LaVoy, New Rochelle, N. Y. Adapting a Two-Man Saw for One Man to Use a two-man crosscut saw, I cut a very 6 or 8 in. longer than the distance between SMALL TREE 1 Mt me uy the two handles. On one end of the stick was a natural fork; like a wedge and then notched. | The stick was sprung into place between | the handles to form a bow.—F. W O MAKE it possible for one man to use | small tree off so that the trunk was about | the other I tapered | Improv Seed EEDL to gr¢ jn @ ger! trated. from 8 t¢ that slop: along th to drain Four | above tk NEW HYGIENE FOR MEN PAST 40 By Byram C. Kelly, A. M., LL. D. Min AL authorities agree that 65% of all men past middle age (many much ASHES younger) are afflicted with a disorder of the prostate gland. Aches in feet, legs and The la back, frequent nightly risings, sciatic pains, aid in are some of the signs—and now, a member of the American Association for the Advancement of Science has written a remarkably intere sting frame. Free Book that tells of other symptoms and covered just what they mean. No longer should a man h of oe : a each 0 approaching or past the prime of life be content : t to regard these pains and conditions as _inevi- tin or S table signs of approaching age. Already more [MM hold the than 10,000 men have used the amazing HM holes in method described in this book to bring better Jass to health—and to restore the prostate gland to its glass proper functioning. Send immediately for this [the sam book. If you will mail your request to the The | Electro Thermal Company, 4036 Main Street, with asl Steubenville, Ohio—the concern that is dis : tributing this book for the author—it will be These s sent to you absolutely free, without obligation. JM screen r Simply send name and address. But don't Hj; place delay, for the edition of this book is limited. the seed (Western Office, Dept. 40A, Los Angeles, Calif, ; Agents Wanted! pee Salesmen~Distributors to use and introduce attachment , ND that makes Fords run on 94% = air. THERMOSTAT on ex- diffe haust automatically turns . down needle i emedaae ~| necessa’ warms exac' or Manual says - A by hand. connect Blancke Auto Thermo and ea: Control Makes porns: ae easier winter or struct t ummer—saves half gas and o,l—cuts Num SAS bills ene: half—reduces carbon ormation one-half. Sells on sight to | ductan every Ford owner as easily as giving | him a $100 bill, because it saves $100 every 10,000 miles. ic now uses should as standard equipment thermostatic carburetor control under lanck: there a license. You can make Big Money selling 2 Som wal cae you without copy se pe 4 makes you from $250 toes 2.000 e month prot of your own tha! Write for free circulars Now INDUC 602 w. Lake Street wil A.C. Blancke & Co. s23Mi20"chice Bee. Ef Gla 5 kez | SPORT BODIES for FORD and CHEV. 430 at 9345 ZN i oo Life-size gg paper $Y ca unpet| patterns x ° aed SLUNG Diag pad | small cost! We are manufacturers and our quantity Gar unig enables us to quote exceptional a, = shipping methods save you 73% in FRE TC once for fre articulate on Central aes. Ou “y= eurD A FoR ee sent anywhere on receipt of 25c in ¢ tam> Te TODAY! CENTRAL AUTO SUPPLY CO. Dept. 122, LOUISVILLE, KY. connec than o atrang The Gasoline Engine on the Farm; Its Wit} Operation, Repair and Uses of any By XENO W. PutNaAM A useful and practical treatise 0? the the modern gasoline and kerosene engine, its construc tion, t ae management, repair and the many uses to which it can switch It considers all the Y applied in present- -day farm life. various household, shop and field uses of this up-to-date switch motor and includes chapters on engine installation, powe! transmission and the best arrangement of the power plant under in reference to the work. Cloth 527 pp. 179 illustration Price, $3.0 POPULAR SCIENCE MONTHLY ._ 225 West 39th Street New York City, N. Y- with t

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5% of ~ much der of gs and Pains, nber of cement ‘resting content ; inevi- y more mi; Its reatise on struction, p-to-date on, power wer plant ce, $3.00 y, N.Y. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Improved Germination Box Gives Seedlings a Vigorous Start EEDLINGS have an excellent chance to grow sturdily when they are started in a germination box of the type illus- trated. It is made of any available wood, from 8 to 12 in. deep, and with a bottom that slopes toward the center. Three holes along the center line allow surplus water to drain out. Four blocks are nailed in about 3 in. above the bottom to support the screen METAL CORNERS 7 HAND HOLES he ==,/ WIRE SCREEN The layer of ashes and slanting drainboards aid in controlling moisture content of soil frame. This is a light wooden rectangle covered with ordinary fly screening. At each of the four upper corners a piece of tin or sheet metal is fastened as shown to hold the glass cover-pane in place. Hand- holes in each side of the box allow the glass to be lifted when necessary and at the same time provide ventilation. The lower section of the box is filled with ashes, which should not be too fine. These should be tamped down so that the screen rests on them. Above the netting is placed 2 or 8 in. of good soil, in which the seeds are planted.—W. F. SANDMANN. Aerial and Ground Switches Are Useful in Testing Radio Sets ? TESTING various radio sets on different types of aerials, it is often necessary te change the aerial and ground connections. This can be done quickly and easily if the experimenter will con- struct the switching panel illustrated. Numbers 1, 2 and 8 are ordinary in- ductance switches. Switches Nos. 1 and 3 should have as many switch points as there are sets to be tested. Switch No. 2 should have as INDUCTANCE many switch points SWITCHES as different kinds of aerials are avail- able. In operation, the aerial post of the sets to be tested or compared are con- nected with bind- ing-posts A, B, C, and D, the aerials with binding-posts .E, F,G, and H, and the ground posts of the sets with J, J, K and L. The ground is connected with binding-post M. If more than one ground is available, duplicate the ‘rangement for the aerials. With this switchboard, the aerial post of any set can be connected with any of tne aerials available by movement of switches 1 and 2 to the corresponding ‘witchpoints. The ground post of the set under selective test then can be connected with the ground by means of switch 3. AERIAL POSTS i oOGr SETGROUND SET AERIAL POSTS POST POSTS GROUND Diagram showing switch connections *B.V.D.” Union Suit (Patented Features) Men’s $1.50 the suit Youths’ 85c “B.V.D.” Shirts and Drawers 85c the garment Men’s“B.V.D.” Underwear in Fancy Materials at Various Prices The B.V.D. Company, inc, New York There Is Only One “B. V.D.”’ Underwear It Is Always Identified By This Red Woven Label rode Mark Reg US Pit Off ancl Foretgn Countries) For its cool comfort, long wear, and fa- mous fit, “B.V.D.” is everywhere the underwear of men who demand these un- Varying qualities in their undergarments Sole Makers of “‘B.V.D.’’ Underwear a; © 1924 The B.V.D. Co., Inc, send for Ow oe BATTERY CHARGING PAYS RGAINS ‘ecoessories at Add battery charging profits to your pres- | ices. Buy direct = thi Oo } Pr oon, Say Croet pov o— Day Charging Outfit. nly $20 } 1500 to*3000 a Year’ ent business! Small cash payment brings | lets your profits balance with e surplus besides. Thirty day AUTO TIPE free trial on money back guarantee. Yo i ke $150 to $300 hly. SALES CQ. Start now to make big profes by Fog Write today for Bulletin 824. Ave., Chi HOBART BROS. CO. Box P 8, Troy, Ohio Newsstand sales of Poputark Science MOonrTHLy are increasing so rapidly that some readers have found it difficult to obtain their monthly copies. Make Leave a definite order with your dealer or, better, SUBSCRIBE TODAY. sure of yours. NS —— — eae ee Re ee ee re. Ue. Um. Ue. Um. OU. OU. OU. OU. Um OU. OU. EU) POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City GENTLEMEN: [Inclosed please find $2.50 for a twelve months’ subscription to POPULAR SCIENCE MONTHLY. POE AR OTS ole 6 aca is wcamiaw. ws nad clew la Xialetatelois amrenbitoinna wanes CUP 6: , atic esa ancl a len 10a : Acid 50c for Foreign Postage, Aug. '24 | | |

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102 21 Jewel.~ Extra thin STUDEBAKER The Insured Watch Only $1.00! The balance in easy monthly payments. You get the famous Stude- baker 21 Jewel Watch—Insured for a lifetime; a choice of 54new Art Beauty Cases; 8adjustments, ~ pe heat, cold, isochronism and 5 positions—direct from the maker at lowest prices ever named on equal quality. Write today for FREE BOOK of Advance Watch Styles. Fine Chain FREE! For a limited time we are offering FREE with the Studebaker Watch a beautiful pattern Studebaker Watch Chain. Write now while offer lasts. Mail Coupon for FREE Book Send at once and get a copy of this bbook—FREE! See the newest, beautiful, advance styles in Stude- baker Art Beauty Cases and Dials. Read how you can buy a 21 Jewel Studebaker Insured Watch direct from the maker—save big money —and pay for it on easy monthly payments. for our free book. It 7 Write! will post you on watch styles and watch values. Send coupon at once. Get Free chain offer today while it lasts. Studebaker Watch Co. Dept. 238 South Bend, Ind. Canadian Address: Windsor, Ont. white gold—ex- cellent time- eee fold or speciaifo er Ne. 1-W. » STUDEBAKER WATCH CO. Canadian Dept. 238, South Bend, Indiana Winks Dnt: Please send me your Free Book of Advance Watch Styles and particulars of your $1.00 down offer. OS eee ig WE ae es, one of our live wire $20.77 a per day for 217 days. =\\ Giidell and bg sold over $25,000 in 2 years. .* earned $100 . E. Mendenhall his commissions in a few months from $100 @J to over $500 per month. Every Home, Auto P Store and Factory a Live Prospect—Kceeton, Soom, and others, never sold Fire Extinguishers before. Our ial training course starts you on road to success first day- i now employed, we can show you how to make big money Susing spare —. Rv po ag ant sce Necessary, Get our new Plan. Terri THE FYR-FYTER CO, MOSS 5 FyreFyter Bi Bldg. Dayton, 0, HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY How to Scrape Engine Bearings By Ray F. Kuns Principal of Automotive Trade School, Cincinnati, Ohio MECHANIC came to me witha problem the other day. ‘Mr. Kuns,” he said, “every time I drive this car a few blocks, I get a new knock. I have taken up the bearings a half dozen times, but inside of a mile the engine is knocking again. What is the trouble?” An examination of the job showed that an oil line was clogged. The mechanic would set up the bearings, and, as soon as he drove the car far enough to warm it up, the main center bearing would burn out again. Finally he had to scrape in a new center bearing. In a bad case of burned and damaged engine bearings, it is necessary to install new ones, as it always is when the wear is considerable and they cannot be adjusted or taken up in such manner as to insure satisfactory service. In either event, scraping is the usual method resorted to in refitting the job. A A possibility the experienced mechanic always bears in mind is that continuous service causes a coating of grit and glaze to be deposited on the surface of the babbitt. As the shaft must ride on this, pro- tected only by the oil,*it is likely to start cutting the shaft journals more quickly than would the babbitt itself. In many shops the practice is to remove this coating with a scraper and it is well known that this sur- face coating dulls the scraper rapidly. Once through it, the babbitt is soft and easily scraped. The suggestions given last month in removing and reassembling bearings ac- cording to marks, must be observed when refitting bearings by scraping. Extreme care of shims is necessary. If a complete job of refitting is needed, then it is essen- tial that the engine be removed from the car and turned up on the bucks or a bench to give easy access to the work. Prepare the job by cleaning inside and out with kerosene. Remove the transmission, fly- wheel, oil pans, cylinder head, and so forth. A poor job of scraping, marks (above), and bear- ings that have been prop- spotted (at right) EMOVE all rod bearings, remove and lay aside the piston and rod assembly, and remove all the caps from the main bearings. Next, lift out the crankshaft and test it for straightness. This is done by placing it on the bench with the two end bearings resting in V blocks. These may be wood or, better still, of brass or cast iron. The center main bearings are tested to see whether or not the shaft is sprung. The gage may be made from a piece of wood clamped on the bench in such man- ner that a pointed end rests close to the center journal. In testing, use a thickness gage between the end of the indicator and the shaft, testing in all positions. If more than .002 in. misalinement is found, it which shows the scraper erly and improperly will be necessary tg straighten the shaft fo best results. This is done on a straightening preg or, if nothing better is at hand, an auto. mobile jack may be set on the center bear. ing, and a chain run around the end bear. ings and over the jack. While this method will take much time, it will give gooq results where the equipment is limited, It is well, of course, to test the journals to see if they are round. If they are ou) more than .002 in., the shaft should be re.| ground. Where minor scores show on the| shaft, they may be dressed off with a fine| cut file, after which the journal is polished. with number 00 emery cloth. With the shaft clean, straight, and pol- ished, the scraping may proceed. First,| take a light cut from each of the upper halves of the main bearings. Next, puta very small amount of bearing blue on each of the shaft journals, rubbing it with the, finger until it js smooth andeven, Then lay it in| place and turn it! several times to get an impres| sion on the bear- ings. Use the! bearing scraper| to remove spots) where the blue| indicates that! theshaft touches. | Proceed with! the scraping and| testing until a good bearing is shown on all the mains at once. At least a 75 per| cent bearing should show before the upper’ halves may be considered finished. | Now fit the lower halves, having first, scraped them to remove the scale. Test by bolting the cap to the case. Then loosen the cap to allow the shaft to turn freely. Fit the front and rear bearings in the same manner. Provide just the amount of shims on each bearing so that when the| bolts are locked tight, the same amount a drag is evident on each one. In scraping bearings, a slightly greater amount of drag is permissible than is allowed when bearings are adjusted or merely taken up, because the new surface| of the babbitt is softer and will seat more) quickly than when the old surface is in, contact. The fitting of rod bearings by seraping| is very similar to the process of scraping main bearings. It should be remem- bered, however, that the rod must be kept) in line with the cylinder. Methods 0) alining rods will be treated next month. IMPROPERLY SPOTTED — Prizes for Photographs F YOU have made or are making any article with the aid of PopuLar ScrenceE Montnty’s blueprints, don't fail to make a photograph of your handiwork. Then send us a print. We are always glad to see such photo- graphs, and for each one considered worthy of publication we will pay $2. Address the Home Workshop Editor. Popular Science Monthly, 225 West 39th Street, New York. = pe ee Ca: ] UI i ply, sc | sary? | portag and sé Wh serve, using detact doubl; food 2 alway: A g than — place viding ward be any | —pref comm attacl | canoe a thw gunw ger of sibly shoul: | the o | grub. Th | wide white toget Th hinge one | | extra | Sary NESS ¢ | and t one s and ends. smal] as loi screy | folds } box, Th each by « screy bit h A Tod, two | one j unde place

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na, J 7 ry to aft for is done | Press, | auto- r bear. 1 bear- nethod > good ited. urnals| ATE Out} L be re.) on the | a fine| olished | nd pol- First, “Upper! » puta on each | ith the| ‘ill it is| d even, it in| turn it| mes to| impres- e bear-| se the! scrape e Spots) e blue| that| ouches.| 1 with! ing and Own on 75 per| e upper ng first, Test by! 1 loosen freely. ; in the Lount of hen the| Jount of| greater| than is) sted or surface | at more! ce is in) _— scraping remem- be kept} hods of! month. | } a yhs vaking PULAR || don't your “* shoto- idered ay $2. “ditor. West — HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Canoeist’s Grub Box Serves also as Dining-Table By Leroy William Hutchins UFFLE bags and packs often are inconvenient for the camp food sup- ply, so why use them when it is not neces- sary? The canoeist who does not have to | portage can carry a grub box as easily and safely as the auto-camper. While any box of suitable size will serve, added convenience may be had by using a box with a special table top and detachable legs. Such an arrangement is doubly handy by reason of having the food always ‘‘on the table’’—the table is always set. A grub box should not be any wider than the flat floor of the canoe at the place it is to rest. A good position, pro- viding there is no live cargo, is just for- ward of the stern thwart. It should not be any higher than the depth of the canoe —preferably a little less. And it is good common sense to have thongs or straps Grub box open, detail of leg sockets, and method of fasten- box in the canoe, AW ing the FASTENING STRAPS attached for fastening the box to the /canoe. This may be done by lashing it to |a thwart or, particularly with the open- | gunwale boat, to the gunwales. The dan- | ger of a box “slipping its moorings,” pos- | sibly at a critical moment, is real and | should be guarded against. It is, in fact, | the one argument against the use of the | grub box. | The box illustrated is 2 ft. long, 1 ft. | wide and 1 ft. deep, made of 5-in. clear white pine. Simple butt joints, held together by screws, are used. The cover is made double—two lids hinged to opposite sides of the box and one folding onto the other—to provide | extra table space. This makes it neces- | Sary to have one side of the box the thick- _ ness of the cover board lower than the other; _and the under lid must be the thickness of | one side board less than the box width, and cut short enough to fit within the ends. To receive this lid when it is closed, small strips, 14 in. thick, 34 in. wide, and as long as the inside width of the box, are | Screwed inside the ends. The other lid folds down to form an over-all top to the box, and is fastened by a small hasp. The lids, whether made of one piece each or two or more, should be reinforced by end battens about 1 % in. wide, Screwed on, the screw heads being sunk in bit holes about 14 in. deep. A simple brace for the lids is a small tod, either metal or wood, slipped into two holes bored at an angle of 45 degrees, one in the side of the box, the other in the under side of the leaf as it is opened into place, (Continued on page 104) 103 ENTS TRADE MARKS COPYRIGHTS PROTECT YOUR IDEAS ANY NEW article, machine, design or improvement thereof, or any new combination of parts or improvements in any known article which increases its efficiency or uscfulness, may be patented, if it involves invention. If You Have Any New Ideas which you feel are useful, practical and novel, take prompt action to protect your rights. If you have invented any new machine, or new combination of parts, or improvement, or any new design or process; SEND DRAWING, MODEL OR DESCRIPTION of it for information as to procedure to secure protection. Write Today for Blank Form “Record of Invention’’ USE THE COUPON attached, and immediately upon its receipt I shall send you this form to be returned to me with drawing, description or model of your idea; promptly upon receiving your idea I shall write you fully as to procedure and costs. DRAFTING and SPECIFICATION ROOM of CLARENCE A. O'BRIEN, Registered Patent Attorney, Washington, D. C. No Charge for Above Information All communications are held in strict confidence. thorough attention is given to each case. I offer you efficient, reliable and prompt service—based upon practical experience. Highest references. WRITE TODAY for free books ‘‘How to Obtain a Patent” and “‘Invention and Industry.’’ These books will give you valuable information, and they may save you much time and effort. Send for them NOW. My practice is devoted exclusively to United States and Foreign Patents and Trade Marks. Write me freely, frankly and with full confidence; it is very probable that I can help you. Write TODAY. CLARENCE A. O’BRIEN REGISTERED PATENT LAWYER Member of Bar of Court of Appeals, District of Columbia, United States Court of Claims, Supreme Court of United States, Supreme Court, District of Columbia My personal, careful and Practice Confined to Patents, Trade Marks and Copyrights : -------FREE COUPON --------- : ql CLARENCE A. O’BRIEN, Registered Patent Lawyer, Washington, D. C. 885 Security Savings and Com’! Bank Building, directly across street from U. S. Patent Office. Please send me your free booklets ‘‘How to Obtain a Patent”’ ar ‘Invention and Industry” and blank form ‘*Record of Invention”’ - without any obligation on my part. INVENTION MA - AND - INDUSTRY OBTAIN A DN oo aoa oie barb wie 4S 0:0 Kieie bes 406 61 O SN ORS CS Hate Ke geasees'e's ; PATENT “4* CO eee err Tee st rt eT Important: **Write or print name clearly.””

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ELECTRICAL EXPERTS IN DEMAND Good positions await trained men. Salaries of $12 to $30 a day not unusual. Tue Evecrricat field needs men. It needs them badly. Hardly a week or month passes but what some new use for elec- tricity is discovered. Each new use means new positions—better positions—for men who have trained themselves as experts in this wonderfully fascinating work. Why don’t you study electricity and pre- pare for a good position at a good salary? You can do it right at home in spare time through the International Correspondence Schools. Best electrical home-study courses ever offered. Endorsed by Edison and Steinmetz. Successful students everywhere, Mark and mail the coupon to-day for descriptive booklet. oe eee eee eee ae TEAR OUT HERES STE Ss TERNATIONAL, CORRESPONDENCE SCHOOLS 605-D, aarneees. Penna. Explain, eases Ls aod me, how I can qualify for the position, or in the subject, before which I mark X. ELECTRICAL ENGINEER ommend ENGINEER Electrician Electric Wiring SALESMAN N SHIP Electric ADVERTISING MAN Electric Cer Running Window a ectric Traction int’; ee RAILROADPOSITIONS Electric Machine Designer pret | cae al reietene Expert » ll BUSINESS MANAGEMENT ‘ate Secretary a] REOHANICAL ENGINEER Business Correspondent Nooesee”” Practice renee ne a ieee rend Sreten an Accountant rattic anagement CIVIL NGINEER Commercial w GOOD ENGLISH STATIONARY ENGINEER CIVIL SERVICE Railway Mail Clerk Textile Overseer or Supt. Surveying and Mapping pore A — pono Pl Drafteman Architects’ Blue Priats PLUMBING AND HEATING AGRICULTURE Sheet Metal Worker ee Spanish Navigator Automobiles RADIO Name 4-30- Present Business oe Occupation Address Street and No City. State Canadians may send this coupon to International Corre- epondence Schools Canadian, Limited, Montreal, Canada PATENTS BOOKLET HIGHEST REFERENCES PROMPTNESS. ASSURED BEST RESULTS Send drawing or model for examination and report as to patentability WATSON E. COLEMAN, Patent Lawyer 644 G Street N. W., Washington, D. C. Chemicals, Reagents, Apparatus Laboratory. Supplies. Send for our Free tIlustrated Price List Queens, L. 1., N. Y. EOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Canoeist’s Grub Box (Continued from page 103) The legs are 1 by 114 in., 2 ft. long. The combination sockets and handles are bent to the shape shown by hammering sheet copper with a small ball-peen hammer into a form cut in a block of hard wood. When the socket is shaped, the copper is removed from the block, the outer edges are trimmed to the right size and shape, and holes are punched or drilled for screws. A triangular piece of wood is fitted to separate the legs after the sockets have been fastened in place. The lower straps, through which the legs are slipped, are strips of metal 114 in. wide and about 6 in. long. To make the loops the right size, the strips are bent around the legs to be used. A good finish may be had by applying a coat of white shellac, followed by one or more coats of spar varnish. Gasoline Camp Fire N MANY states open fires along the highways are not permitted and auto- campers are compelled to carry some sort of stove. Many types of safe and ex- cellent gasoline stoves are available, but some campers, who ordinarily prefer an open wood fire, use an impro- vised gasoline stove made as shown, when an open fire cannot be laid. It con- sists of a large can, about 1 gal. in size, prefer- ably without sol- dered seams. The can is per- forated with a ring of %- or 1- in. holes a little more than midway from the top, as indi- cated, to supply air and avoid excessive smoking; the correct number may be found by trial. A folding stand and dish- holder is made of sheet-iron strips. A layer of sand 1 or 2 in. thick is placed in the bottom. In use, a pint or more of gasoline—the exact quantity for preparing a meal to be determined by trial—is poured into the sand and ignited.—G. A. L. oop REST FS FORUTENSILS The simplest type of gasoline stove Coming Worksho, Features NIQUE Experimental Radio Set Built on Sectional-Bookcase Plan How to Make a Large Filing Cabinet Cheaply Using Common Chopping Bowls to Make Ornamental Lamp Shades Utilizing Old Wood to Build an “Antique” China Closet How to Care for and Store House Screens How to Build an Aquarium and Stand A Six-Inch Jointer for the Workshop the Man With an Idea I offer a most comprehensive, ex- | prompt, perienced, efficient service for his i| bee legal protection and the [fee i ] development of his proposition. fa Pa Send sketch, or model and description, et for advice as to cost, search through [Ba prior United States patents, etc. Pre- [Ee liminary advice gladly furnished with. By Out charge. My experience and familiarity with various arts, frequently enable me to 4 accurately advise clients as to prob- |PeE a able patentubility before they go to : @4 any expense. Booklet of valuable information and form for properly disclosing your idea, free on [ff request. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington,D.C, Rooms 809-810, 41 Park Row H Cortland 0721 New York City }Pj 1a | oe iit Ree 5 BML eee = * a Te , Make $75.00 a week and up, selling our fine made-to-measure, all-wool . suits, direct to wearer. Biggest values — ' positively: sell on sight. Biggest commis- sions paid in advance. We attend tode- livery and collections. 6x9 swatch sam- ples—over 100 styles all one price—furnished FREE. Part or full time men write at once. W.Z. Gibson, Inc.,161W.Harrison St., Dept. H-25, PROTECT PATENTS. sro IMPORTANT Mason, Fenwick & Lawrence, Patent and Trademark Lawyers, Washington, D. C, New York and Chicago. Established over sixty years. Highest references. Nee aire SINCE 1905 , W.LOVETT Stcuaty inc BLOG [YAN MASS SENO FOR FREE BOOKLET NIIONS 25 inmercialized Gm A CASH OR ROYALTY BASIS j eA Sor FP NERS ALTY BASIs SI for fhe INVENTOR and MANUFACTURER, | /n Business 25 Years Complete facilities ‘References ADAM FISHER MF¢.C0. 183-D St.Louis, Mo, PATENTS | | RADE-MARKS, COPYRIGHTS AND PATENT LITIGATION | Nrite for advice and imstruc- con how to proceed, costs, etc. i Hand Book with illustrations of 100 Mechanical) Movements sent free on request. ALBERT E. DIETERICH | Patent Lawyer and Solicitor Successor to Fred G. Dieterich & C 681A Ouray Bldg. WASHINGTON, D.C p. C4

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AW 25, Chicage TECT R TANT TIONS ent and Desc. led over BASIS TURER. MCCS 's, MO, ae ne TIGATION) [echanical] c | LICH | ; | Co. . cl ON, D- C4 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY | Building a Camper’s Permanent Stove of Bricks T° MAKE this camper’s permanent stove, about 100 bricks, a sack of sand, and half a sack of cement are re- quired. The inside width is about 3 ft. and the over-all length, 5 ft. A double course of bricks is laid for the footing and the second course is laid Ample space for boiling, broiling, and frying makes this an excellent camp stove over the center of the first. The brick- work is five courses high. An iron plate is placed across the walls for the flue and the bricks are drawn 1 in. for each course to form the chimney. The stove is covered with a piece of sheet iron for boiling purposes, and several iron bars for broiling. An angle bar runs across the front end. The exposed brick surface may be given a coat of cement and sand mortar all over, or merely where shown.—HERBERT C. CROCKER, Edwardsville, Il. Shoe Rack Saves Space in Crowded Clothes Closet anaaeieg space in a clothes closet always is at a premium. This may be saved by the use of a shoe rack placed across the base- or mop-board and backed up to the very end of the closet wall. By its use the floor is kept clear of shoes. The rack can be made by knocking the bottom out of a box and _ inserting shelves. The box may be placed on a +] board set across the iy closet, if it is not wide enough itself. i It is a simple matter, however, to build the rack especially to fit the closet. The wood should _ be ASIOCK shellacked or painted. — DONALD D. SIMoNDs. Construction of the rack Cardboard Sanding Blocks FIND that Yara elaWaraalavas, SP aYalataVaVa eta as D. heavy corru- \GRRARR Roos gated cardboard CORRUGATED from shipping car- SANDPAPER’ CARDBOARD tons makes excel- | lent sanding blocks. The blocks may be | made in any size or thickness desired by | folding strips of cardboard. The edges may be given any curvature for sanding moldings and rounded surfaces, and no time need be lost in making shaped wooden rubbers.—R. E. DEERING, Clements, Kan. TRADE-MARKS COPYRIGHTS NO CHARGE FOR EXAMINATION AND OUR OFFER: INSTRUCTIONS. HAVE YOU AN IDEA? YOUR FIRST STEP before disclosing an invention. The inventor should write for our blank form— “Record of invention”’ This should be signed and witnessed and returned to us together with model or sketch and description of the invention for examination and instructions. No charge for the above information. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK 1i—How to Obtain a Patent Contains full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illus- trated and described, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, and Law Points for inventors. 2—Our Trade Mark Book 3—Our Foreign Book . Shows the value and necessity of Trade- We have Direct Agencies in all Foreign Mark Protection and gives information Countries. regarding Trade-Marks and unfair com- We secure Foreign Patents in shortest petition in trade. time and lowest cost. Our Main Office, in the Victor Building (Opposite U.S. Patent Office), Washington, D.C. WE REGARD A SATISFIED CLIENT Highest References—Prompt Attention—Reasonabdble Terms Patent Attorneys Main Offices: 760 Ninth Street, Washington, D.C. As our best advertisement, and will furnish to anyone, upon request, lists of clients WRITE TODAY: New York Offices Philadelphia Offices Pittsburgh Offices Gentlemen: Please send me FREE OF CHARGE your books as described above. in any state for whom we have secured patents, VICTOR J. EVANS & CO. 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. oupon Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. TET cs eee OE EE a ee LO. REE Cr CT

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106 DON’T STALL but go get that job Strongfortize/ OU may have a go-getting brain, but you'll never get and hold a man-size job until you’ve developed a_ go- getting body, too. In the business, mechan- ical and industrial world, just the same as in athletics, success is very largely a matter of muscle. STOP FIGHTING! If you just can’t help fighting then take a wallop at some mean looking stranger. Don’t be always picking on yourself. Don’t be always putting some obstacle be- tween success and = you. Stop bullying, despising and degrading the only body that you'll ever have. The average employer will forgive a little wildness but he never can forgive physical weakness in the men he hires. He knows that poor health spoils the morale of an organization andthrows a monkey wrench into the efficiency machine. Keep on ailing and you'll keep on failing. A man is as good as the muscles cn and in him...no stronger than his weakest part. STRONGFORTISM, the science of health, strength and virility with scientific muscularity produces great business and industrial leaders because it develops the full powers, mastery and rewards of complete manhood. Strong- fortism strengthens the heart, stimulates digestion and assimilation, ends constipation, makes good red blood and covers the body with a wicked coat of fighting muscles. Thou- sands of my pupils trace direct to Strongfort- ism their triumphal progress from failure, futility and half-death to the supreme rewards of leadership in the world’s work and utter happiness in family, social and sex life. STRONGFORrTISM is certified success and manhood, and you'll find it so. I'll be more than glad to give you the big lift to the high places if you’ll show a kindly disposition toward your best old:pal .. . that’s you! LIONEL STRONGFORT Physical and Health Specialist for 25 Years Dept. 1448 Newark, N. J., U. S.A.

STRONGFORT The Perfect Man

A Terribly Truthful Book—FREE Years of my busy life have been spent in writing for you ‘‘Promotion and Conserv ation of Health, Strength and Mental Energy.” It’s a daringly frank expose of the dangers and disasters, the glories and triumphs that sur- round every living human body every minute of the day. You'll call it the most astonishing body literature you ever read. No cost, not even postage. Just send the coupon Now. = = secure the . Tsar ng a nay firm- tothe ling th PLAPAG vet—easy to apply. Over 250,000 Now In Use We have proved to hundreds of thousands of sufferers from hernia (rupture) that to obtain lasting relief and develop

port agegra’ condition. The Plapao-Pad can and does aid the muscles in giving proper support, thereby ren- dering efficient aid to Nature in restorin strength tothe weakened muscles. Being oa adhesive there is no slipping and shifting of pad with resultant irritation and chafing. comfortable to wear—no delay from work. Awarded Gold Medal at Rome and Grand Prix at Paris, ~ rene ie No Mon We will needoen you a trial of now or later. dotely FES for ie today, also also frill Ghee PLAPAO LABORATORIES, Block 716 St. Louis, Mo.

'CEND FOR AG -THIS FORM | DON'T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone # send for blank form **‘EVIDENCE OF CON- CEPTION”’ to be signed and witnessed. A sample form together with printed instructions ® will show youjust how to work up your evi- dence and establish thesame before filing ap- plication for patent. As registered patent-at- torneys we represent hundreds of inventors all over the United States and_Canada in the ad- vancement of inventions. Our schedule of fees willbe found reasonable. The form “Evidence of Conception,” sample, instructions relating to obtaining of patents and schedule of fees oc —_ request. Ask for them,—a postcard § will co PATENTS ANO \WTRADE MARKS (ANCASTER ie &ALLWINE

274 Ouray Bldg. WASHINGTON, D. C. Originators of fo:ms ‘Evidence of Conception.”

PATENTS As one of the oldest pat- ent firms in America we give inventors at lowest org ge charge, a scr- vice noted for results, evidenced by many well known Patents of extraordinary value. Lace atent-Sense, free. t., Wash., D. C. Estab. 1869.

Lacey, 648 F St. Patent Litigation Trade Marks PATENTS ‘=. Handbook of instructions, ‘‘How to Protect In- ventions,” sent free on request. R. H. FRAVEL, Patent Lawyer Formerly of the U. S. Patent Office Examining Corps

Room 2503 McLach!en Bidg. WASHINGTON, D.C.

is) —_

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY How to Unscrew a Pipe Cap | without a Wrench Bawne purchased a radiant gas heater, I found myself unable to connect it because I had no pipe wrench to remove the cap on the %%-in. gaspipe. This cap was on tight and among all my tools there was nothing that would turn it. I took a piece oS wis Fo Bm raigatl Seventy-eight Years * ponies a heavy of P ractice screwdriver, put ean wire clothes line pe pecs sie HE firm of Munn & Company filed its ed le first application for a patent in 1846, and the wire, he wire —— — for seventy-eight years has endeavored to keep the cap about four times and raised up on : ° . i the ‘atte while holding the loose end of pace with the inventive genius of the United the wire in my left hand. The way that States. An experience of many years is at ire took the cap off was a real surprise. : ° = oc anes tl ea mee pao your disposal. If you have an invention have taken a firmer grip.—R. C. WHITE, which you wish to patent, send your sketches Dallas, Texas. or model together with a description of your Rubber Buffer Will Protect device, explaining its operation, and you will Woodwork from Mallet receive prompt, courteous attention. I eps anne Write for our Handbook on parts of fur- 7 | niture together, —— = pret eaten! ay A full and complete booklet on Patents, Designs, and my mallet or HOCKEY PUCK Trade-Marks, Foreign Patents, Copyrights, Labels hammer a heavy “i and Patent Office Practice with an explanation about piece of rubber. It is simply a rubber our methods, terms, etc. hockey puck with a hole bored in one side All communications strictly confidential and a handle inserted.—S. B. Keepin touch with the inventions of the world by reading Home Workshop Chemistry SCIENTIFIC AMERICAN (Continued from page 106) The MONTHLY MAGAZINE with a special appeal Iron and steel usually are etched with to every man of inventive genius. Recent rulings of three parts of water to which one part of the Patent Office, descriptions of the latest patented concentrated nitric acid has been added. inventions, legislation and court decisions affecting A better formula is half a glassful of a patents, are noted in this authoritative publication. concentrated solution of potassium bi- chromate in water to which a quarter of a MU me hi & COMPANY glass of concentrated sulphuric acid is | added. This solution also will etch Patent Attorney ° ame and brass successfully. 683 Woolworth Building, New York City | Aluminum must be treated differently; Scientific American Bldg., Washington, D. C. | it is etched with dilute hydrochloric Tower Building, Chicago, III. (muriatic) acid. Hobart Bldg., 582 Market St., San Francisco, Cal. When the place to be etched or en- graved is very small, use a dropper to take up the etching fluid and place it on the name or design drawn through the wax. Renew the drops every five minutes or until the acid has penetrated deeply enough. When the metal has been sufficiently etched, wash it in running water to re- move all traces of acid mn then take off NV ENTO Fe &, PROTECT et ee This can be accom- YOUR IDEAS 1S i os . Send for our Guide Book, HOW TO GET A PATENT, solvent such as acetone, benzene or and Evidence of Invention Blank, sent Free on request. Tells turpentine. our terms, methods, etc. Send model or sketch and description of It must not be forgotten that the metal your invention for our Examinae ¢—- - = ++ --- ----- een - oe eee een has to be perfectly clean before the wax is tion and Instructions without applied, and after the wax is removed all charge. 9a . one must be taken off. €n a tool has been etched, it is well to wash it with benzol containing a little wax RAN DOLPH oe co. | to prevent rust.—ERnest Bape, Pu.D. Dept. 130, Washington, D.C. Van Nuys Building, Los Angeles, Cal.

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SALARY REPAIR MAN |* CHAUFFEUR |* Put Your Name ON Tis =P ay-Roll Men like you are wanted for big-pay posi- tions in the fascinating field of automobile ee oy tee pee on Price Reduced fit yourself for one of these positions. Youdon’t Down goes the price on these famous Auto have to go to school. Books. We have You don’t have to serve an apprenticeship. Fif- teen automobile engi- neers and _ specialists have compiled a spare time reading course that Will equip you to be an automobile expert with- out taking any time from induced our printers and binders to cut the price they charge us. We pass this sav- ing on to our cus- tomers, Mail CouponNow For FREE Trial Partial List of Contents ‘our present work. AUTO BOOKS 6 Volumes Shipped Free Now ready for you — an up-to-the-minute six- | More than 190 Blue- volume library on Auto- prints of Wiring mobile Engineering, cov- Diagrams ering the construction, | Explosion Motors care and repair of pleas- | Welding , ure cars, motor trucks | Motor Construction and motorcycles. Brim- and Repair ming over with advanced | Carburetors and information on Lighting Settings _ Systems, Garage Design | Valves, Cooling and Equipment, Welding | Lubrication andotherrepairmethods. | Fly-Wheels Contains everything that lutch a mechanic or an engi- | Transmission Final Drive neer or motorcyclist or : Steering Frames the owner or prospective owner of a motor car | Tires |. ought to know. Written Y iin insimple language that c ¥ anybody can understand. | Starting and Light- Tastefully bound in ing Systems American Morocco, flex- | Shop Kinks ible covers, gold stamp- | Commercial Garage ed, 2,560 pages and 2,100 | Design and Equip- illustrations, tables and ment . explanatory diagrams, | Electrics ; A library that cost thou- | Storage Batteries sands of dollars to com- | Cars and Repair pile but that comes to | Motorcycles you free for 7 days’ ex- | Commercial Trucks amination. Glossary Only 10c a Day Not acent to pay in advance. First you see the books fin your own home or shop. Just mail coupon and pay express charges when books arrive. You can read them and study them for seven whole days before you decide whether you want to keep them cr not. If you like tha books send only $2.80 in seven days and $3 a month until the special introductory price of $21.80 has been paid. (Regular price $45.) Send No Money Now Don’t take our word for it. See e books without cost. There so much profit in this offer for you, that we urge you to waste not a moment in sending for the books. Put the coupon in the mails to- day. Send no money— just the coupon! American Technical Society, Dept. A.C.20, Chicago, Ill. is _— VA A A AAS A Ks AMERICAN TECHNICAL SOCIETY Dept. A.C.20, Chicago, Ill. Please send me the $-volume set, Automobile Engi- neering for 7 days’ examination, shipping charges collect. If I decide to buy, I will send €2.80 within 7 days and the balance at $3 a month until the $21.80 has been paid. Then you send me a receipt showing that the $45.00 set of books ere mine and fully paid for. If I think I can get along without the books after the seven days’ trial, I will return them at your expense. Addr HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY | well. rem: | making picture frames.—G. E. BLACK. Space-Saving Loop Aeria! Swings from Ceiling By C. A. Oldroyd USPENDING a loop aerial from the ceiling has several advantages over the usual custom of placing it on the radio cabinet or on a table. It can be swung around more conveniently and accurately and removed in a second without unscrew- ing any nuts. Furthermore, several loops of different sizes can be used at will in the same bracket support, if it is made as shown in the accompanying illustration. To the vertical member of the loop is fastened a thin metal pointer, a spacer OMPASS DIS" E>) ,-POINTER ee ‘a : | ie? oo os = ; 7 | ra] |!)|] DISTANCE i asataail pate ci ll VERTICAL | ||| |/] PIECE ' MEMBER}|| |] ||| T| " ‘7 TINSULATORS . hi! Lk see 7 N 49 | xm BRACKET — BRASS Yo, SCREW HOLE : Je ae * NY WI (8 KZ ZL LLL t hax. \ Tr LL Y t popeHHORIZONTAL DISTANCE PIECE- BRASS MEMBER Detail showing ceiling bracket for the loop aerial and direction-finding compass disk or distance piece and a washer, as indi- cated, all being held by a single long wood screw. The supporting bracket is made as detailed and, together with a compass disk of any convenient size, is fastened to the ceiling. In hanging the loop, the small end of the distance piece is slipped through the slot in the bracket and the whole frame is then dropped so that the large end fills the hole in the bracket. In this position the loop is held securely, yet it can be turned in any direction. The leads to the set should be flexible wire. Fitting Unusual Joints N MAKING furniture with difficult joints, parts that have not been cut quite accur- ately often can be fitted by placing them as nearly as pos- sible in their proper position, fastening them temporarily with clamps, or in some other way, and then running a fine saw through the joint to remove the Fine saw cut trues projecting wood a joint accurately that caused the difficulty. If a panel or handsaw cannot be used, a short length of broken hacksaw or bandsaw will do as This plan also can be utilized in Adjustable Vise Holds Small Articles while Being Soldered HE jewelry repairman and, in fact, any one who has had occasion to solder ‘small articles, will welcome 4 method that does away with the usual bent pins and charcoal block. Having a For jewelry, model mak- ing and small repairs lao UNL & structed several of the clamps illustrated from old hinged ruling pens. The base is a cube of nickel steel. A hole is drilled in the center of one of its faces to take the shank of the pen. The parts to be soldered are clamped be- tween the points of the pens, which may be placed in various positions. Ruling pens of this old pattern usually may be purchased cheaply secondhand, if none can be found in the junk box or obtained from a_ drafting-room.— PHILIPPE A. JuDD, Portsmouth, Ohio. Camper’s Three-Legged Chair Will not Collapse Readily erred camper has seen the ordinary types of folding chairs collapse at un- expected moments under the weight of their occupants. The chair shown in the accompanying illustration will neither close nor open unexpectedly, and it is of simple construction. The uprights are 3 ft. 2 in. high and are placed 14 in. apart. The other dimen- | RECESS IN SEAT BOTTOM RECEIVES END OF THIRD LEG Chairs constructed on this principle may be made quickly from any scrap lumber ro sions are in proportion. The principle of construction is not confined, however, to any one size, shape or grade of lumber. It will meet a host of varying tastes and con- ditions. WILLIAM R. LEwis, Eland, Wis. | | | | great deal of repair work to do, I con- | “ae | f ‘Qa eas; 3 &. it.

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trated 1. A of its The d be- h may Ruling ray be ' none tained E A, hair ily dinary at un- ght of in the 1either it is of rh and Jimen- / Log Every Worth While Station With Perfect Ease Be able to get th2 programs you like best any time and with that smoothness and clearness of tone that makes Radio most enjoyable. It’s easy with Stromber¢ Carlson Head Sets and Loud Speakers Their powerful magnets give extreme sensitivity. The layer wound and layer insulated coils enable these instruments to stand up under the highest voltages and to retain their sensitivity permanently. Ask your dealer Stromberg-Carlson Tel. Mfg. Co., Rochester, N. Y. Have You AN INVENTION? If so the WORLD PROGRESS will show you how to Protect and Profit From Your Ideas Sample copy free. One year’s subscription 40c. nd for free book, “WHAT TO INVENT” containing Suggestions to Inventors as to Inventions Needed. We invite manufacturers to address us regarding inventions they want. WORLD PROGRESS PUB. CO., INC. Reom 202 Victor Bidg. Washington, D. C. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY BURN YOUR NAME ON TOOLS witr ARKOGRAF Protect your tools from theft. Write any name, engrave any design on tools and metal with electricity like writing on paper with ay or pencil. somplete outfit $3.50, prepaid anywhere. Interest- ing descriptive circulars free. Write ‘o-day, Agents wanted Arkograt Pen Co., 1171-A East Stark St., Portland, Oregon 21 Jewels aotememmmeniies Aseedy looking top spoils L CUSTOM MADE fits appearance. Get a iberty Custom Made Top. It’s fun putting iton, simple direc- tions furnished. Save a big labor bill. We are manufacturers of tops, side curtains and seat covers, for any make or model car. Amazing values. Special Proposition for Fords, Chevrolets, Dodgesand Maxwells. Write today for big money saving catalog. UBERTY TOP & TIRECO., Dept. E-8 Cincinnati, Ohio | DRESS UP| $3.85 YOUR CAR AND UP Constructing Airplane Kites (Continued from page 72) be covered on the under side. The cover may be a light-weight, tough wrapping paper. The edges should turn over the sticks and be glued down. Glue will re- quire a little coaxing to keep it at work, so go over the work now and then while the glue is drying so as to press down places that have raised up. After the cover is secure, lash the plane to the slanting sticks that are attached to the upright posts of the fuselage frame. See that the planes have equal amounts of overhang to right and left. It will be dis- covered that the lower plane frame ex- tends through the frame of the fuselage, so covering is best done after it is an- chored in place. The framework in place, including the rear plane, is shown in Fig. 4. A brace is run from each side of the fuselage frame to the bottoms of the first pair of upright posts. Where the brace attaches to the upright post, drill a hole for about a 1/16-in. wire on which the wheels are placed (Fig. 4). Cover the fuselage from end to end before covering the under side of the lower foreplane. ‘THE rear or tail plane is shorter than the front ones, but is about the same width; it is 11144 in. by 36 in. The front end is lashed fast to the fuselage frame, but the rear end is left loose to be ad- justed at the most advantageous angle. Its final anchorage can be made with wire or cord. The rudder has a large reed, about No. 8, for the frame and is inserted in holes made for the purpose. Cover both sides of the keel. A movable rudder is not necessary, but might be useful if the keel veers too much to right or left. Control is mostly through the kite line and adjustment of bridle. A two-line good many stunts. A five-string bridle will serve for this kite—two strings from the front stick of the upper foreplane, two from the front stick of the lower plane and one from the rear of the fuselage. When trying out this kite, it was found that the slant of the planes had to be reckoned with, so that the bridle, instead of standing at the usual ratio of 2 to 3, had to have almost the entire allowance given to the fifth string and only a small portion to the first four. In fact, the kite had to be drawn almost straight out, without any angling to the rear. This is an advantage, however, as it gives a more realistic appearance. The propeller does not propel, but is for show. It can be whittled out of a soft piece of pine or redwood, about 34 by 1 by 12 in., as shown at J, Fig. 2. A small hub should be glued to the front block, as shown at H, through which a hole is bored and on through the block to receive what- ever bearing is used for the propeller. The propeller must be free enough to spin | easily, but not so loose as to lop over on the frame of the airplane. A UNIQUE method of making shades for electric lamps out of ordinary wooden chopping-bowls will be described next month by Gladstone Califf. driving plan would be good, as a well | balanced kite could be driven through a | 103 Mr. Bradford Is Right! But the best advertisements of this tobacco are never written From Indianapolis Mr. R. O. Bradford bursts into song: The Pipe of Inspiration I can see him now a-sitting at the desk he loved so well, Late at night, and still hard at it, writing copy good to sell. And he smoked his pipe in silence, while his thoughts to business ran, Guess he’s writing still, for father was an advertising man. First he’d scatter all his papers, till his desk top was a sight; Then he'd turn from his typewriter and gaze out into the night, But when once his thoughts had started, and the work for sure began, Dad would clean his pipe and fill it from the little old blue can. Edgeworth! Bless your soul, you’ve guessed it! Dad was surely sold for fair, On that ready-rubbed tobacco, and he never seemed to care Just how long and hard his hours, or how high the work was piled, All he wanted was the blue can, and he smoked his pipe—and smiled. Pipe of inspiration. Righto. I’m an ade vertising man myself, and I've learned to realize and appreciate just how much Edge- worth means to me when there’s a tough problem on deck, or when work piles up and requires long hours to clear it away. Pass the good word along. It’s Edgeworth that is responsible for lots of good adver- tising copy nowadays. Ralph Otis Bradford Mr. Bradford is quite right when he writes that ‘‘Edgeworth is responsible for lots of good advertising copy” for, as every writer knows, there is inspiration in a good smoke, but the words that fill this column do not sell Edgeworth. As a mat- ter of fact, they aren’t copy at all—they are just gossip about pipe smokers. The advertis- ing that creates Edgeworth smokers is broad- cast from Jones to Smith to Rob- inson by word of mouth. The best we can hope to do in this space is to get another Mr. Jones started. Even if your name isn’t Jones we’ll be glad to send you free samples of Edge- worth if you’ll send your name and ad- dress to Larus & Brother Company, 59 South 21st Street, Richmond, Va. If you care to add the name and address of your regular tobacco dealer we will ap- preciate the courtesy. To Retail Tobacco Merchants: If your jobber cannot supply you with Edgeworth, Larus & Brother Company will gladly send you prepaid by parcel post a one- or two-dozen carton of any size of Edge- worth Plug Slice or Ready-Rubbed for the same price you would pay the jobber.

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110 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY FIVE GOOD BOOKS for LCS ots \ readers of _ BOLDIN B008 ‘‘Popular Science”? Only $1 Each I. C.S. Building Trades’ Handbook A convenient pocket manual for everyone in the | building trades. Tells you everything you want to know about arithmetic, weights and measures, formule, mensuration, geometrical drawing, structural design, masonry, carpentry and joinery, roofing, plastering, plumbing, heating, ventilation, gas-fitting, estimating, elements of architectural design, etc. 372 pages. 189 illustrations. A wonderful bargain at $1. I. C.S. Plumbers’ and Fitters’ Handbook The only book of its kind ever published. Filled with sound, practical knowledge and information that you need every day. A condénsed encyclopedia of the art and practice of plumbing, heating, ventilat- ing, gas-fitting, etc. Contains much new material. More than 50,000 copies sold. 375 pages. 148 illustrations. Only $1. I. C.S. Concrete Engineers’ Handbook A handy reference book worth many times its small cost of $1. Contents—Useful tables, mathematics, loads in structures, mechanics, homogeneous beams, columns, sands and cements, plain concrete, steel reinforcement, foundations, building details, form work, building laws and specifications, etc. 368 pages. 230 illustrations. Only $1. I.C.S. Business Man’s Handbook 175,000 sold. A handy business book that no man should be without. Tells all about business forms, card systems, bookkeeping, correspondence, postal information, definition of financial terms, money and the money market, corporations, business law, contracts, partnerships, commercial paper, law of landlord and tenant, etc. 315 pages. 57 illus- trations. Only $1. I.C.S. Automobile Handbook Tells all about gasoline engines, transmission and control systems, carburetors, self-starters, bearings, electric ignition, tires, automobile management and maintenance, horsepower calculations, how to make quick repairs, how to anticipate trouble, digest of automobile laws, and other useful information that will save you time and money. 301 pages. 156 illustrations. Only $1. These five contain 1731 pages and 780 illus- trations and represent the greatest book value ever offered at the price. Just fill in the coupon printed below—enclose $1 for each book you want, and mail. . You run no risk. Your money will be returned promptly if you are not satisfied. ] INTERNATIONAL CORRESPONDENCE SCHOOLS | Box 7606-D, Scranton, Penna. 1 l I enclose $........ for which send me, post-paid, the Handbooks marked X, at $1.00 each. It is under- ] stood that if I am not entirely satisfied I may return ] i any or all of them within five days and get my money | back. OI BUILDING TRADES’ HANDROOK 1 L] PLUMBERS’ AND FITTERS’ HANDBOOK | LL] CONCRETE ENGINEERS’ HANDBOOK I BUSINESS MAN’S HANDBOOK AUTOMOBILE HANDBOOK { I l a Address. at Conns give you FREE most pleasure and quickest Qa opportunity for profit because %% they are easiest to play— beautiful % in tone — perfect in scale—hand- some in design and finish. Send for Free Book,Successin Music Sj How to Win It” by John Philip : poe and —and details o Frec Trial, Easy Payment plan on any Conn instrument. Men- tion instrument. Cc. G. CONN, Ltd. 832 Conn Bldg. Elkhart, Ind. Rustic Bungalow Solves Housing Problem for One Family By Joe V. Romig The inexpensive method of construc- tion outlined in this article is especially suitable for a summer cabin in the woods. oa on a plot of ground that had been given up by real estate men as impossible, this rustic bungalow solved temporarily the rent problem of a young mechanic friend of mine. The plot stood on the foot slope of a thickly wooded hill and lay in the rear of an improved realty project. It was obtained for less than one-third its actual value. The buyer cleared the timber, which consisted of shoots from 6 to 8 in. in diameter and cut all the straight stuff 4X6" TOP PLATE a 9-0" TIMBER 6X8 SILLS FLOOR JOISTS PORCH JOISTS 4X6 TOP PLATE WALL- 2 > BOARD STRIPS PLAN VIEW CEMENT FOUNDATION Diagram, showing corner of log-cabin type of bungalow, end details of construction up into 9-ft. lengths. He saved these pieces for the side walls of the bungalow. A cheap cement foundation was first constructed and on this were laid the 6 by 8 in. sills. On these sills were set and spiked the rough 9-ft. logs. These were fitted closely together by trimming in places with an ax. By using the thickest pieces for the corners and door and window jambs, a strong and bal- anced locking design was obtained. On the top was spiked a 4 by 6 in. top plate, which carried the 2 by 6 in. ceiling rafters. These rafters extended over the porch. The treatment of the interior was as simple as that of the outside. Strips 114 by 3 in. were nailed on the logs at the proper intervals to catch the joints of wallboard sheets. The wallboard was nailed on with a gap between the pieces of about 14 in., which was later filled and smoothed over with plaster of Paris mixed with glue size and slaked lime to retard its setting. This treatment of the wallboard joints gives a better job than when the pieces are butted closely against each other. The ceiling also was covered with wall- board and the job was completed with a covering of substantial wallpaper. Saw Mortor ATTA MAKES YOUR BIKE A MOTORCYCLE! A highgrade 24 HP. P. ea ite aan uickly on any Soto te nies gallon of of gas. Now! —_ for Complete Descri - It’s the very newest and lat- est help for Sign Painters and Showcard Writers. Let- ter Patterns. Helps the in. experienced and aids the finished expert. Turn out neat signs in less than one- 33 — the usual time. Make Sign Painting and Show- Pr Writing as easy as A, B, C. Samples for stamp. JOHN F. RAHN, D-2433 GREENVIEW AVENUE, CHICAGO, ILL AGENTS 500% PROFIT GENUINE GOLD LEAF LETTERS Guaranteed to never tarnish. Anyone can put them on stores and office windows, Enormous demand, large profits, Paul Clark says: smallest day $28.70. R.L. Reel made $920 in two months. Write today for free sample and liberal offer to general agents, METALLIC LETTER CO. 433A N. Clark Street, Chicago oe Book FREE Squabs selling at highest prices ever known, Greatest market for 20 years. Make money breeding them. Raised in one month. We ship everywhere our famous breeding stock and supplies. Established 23 years, Write now for big illustrated free book, How to Make Money Breeding Squabs, PLYMOUTH ROCK SQUAB CO. .616 H St., Melrose Highlands, Mass. Beautiful Raceabout e Instead of Your OLD FORD ‘ Choice of Four Colors ; Fiat or the mg? fe Ballet "Nose Rad-« y a iator Shell. Send 3 £ for 1924 Free Cat- SS 3 sine of New Auto frei —_ Acces’, Bodies and Speed Equipment. Direct from Factory. AMERICAN TOP AND BODY CO., Beech Street DELPHI. IND. “LIGHTING FIXTURES” Ready to hang. Direct from the manufacturer. Completely wired including glassware. Send for Catalogue No. 26 (Just off the press) Special proposition to Dealers ERIE FIXTURE SUPPLY CO. Desk A. Erie, Pa. BUCHSTEIN’S FIBRE LIMB soothing to your stump— strong, cool, neat, light. Easy payments. Guaranteed 5 Years * all Send for Catalog Today deformities, P. BUCHSTEIN CO., 610-3rd Ave., So. Minneapolis, Mino. Ford Runs 57 Miles on Gallon of Gasoline A new automatic and self-regulating device has been invented by John A. Stransky, 2574 Fourth St., Pukwana, South Dakota, with which automo- biles have made from 40 to 57 miles on a gallon of gasoline. It removes all carbon and prevents sp ark plug trouble and overheating. It can be installed by anyone in five minutes. Mr. Stransky wants agents and is willing to send a sample at his own risk. Write him today.—Adv. FORD tris NOW while we can make dnt Bodies, s~ ry —w Bom am ZR a ee a ee ee ee)

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inter and lat- Painters -RS one can indows, 1] Clark el made for free agents, t, Chicage known, money h. We ng stock } years, se book, Squabs, JAB CO. ds, Mass. sabout D FORD er. cluding No. 26 ) ealers LY CO. ci ton orem IMB at, light. nents. Bc for alk formities, lis, Minn. files line »vice has 4 Fourth automo- gallon of nts spark installed ———— Wonder House of Science (Continued from page 23) that makes them visible. You are in effect looking into the realms of the invis- ible. You are seeing atoms, for you will undoubtedly recall that the little shooting stars called alpha rays, hurled off by radium at a speed of 20,000 miles a second, are picking up negative charges of electri- city from the air and transforming them- selves into atoms of helium. Thus, in her new home, science shows us almost side by side two of her most amazing spectacles—one infinitely small, the other tremendously great—the move- ment of atoms and the activity of the sun. Now, most of the things I have men- tioned thus far belong to the realms of pure science—tc the laboratory. Science, though, is intensely practical, and when- ever possible speedily turns the discoveries of the laboratory to the service of man- kind. And so in its new home Science lets us view a great many of the practical, useful things that have been given to us through scientific research. There is, for example, an exhibit of valuable accomplishments of medical re- search. There are cultures of living dis- ease germs; and there are microscopes in which you may place the germs and study them. Then, turning to graphic, under- standable charts near by, you can see de- picted the methods by which medical science combats these germs. AN adjoining room are instruments by which the United States Weather Bureau makes its forecasts. Use them if you wish, and try to predict the morrow’s weather from what you observe. It should be easy; the instruments are of the very latest types, and plain directions for their use are given. As a matter of fact, I predicted rain when I had read the instruments, and surely enough it did rain the next day. Alongside the Weather Bureau’s exhibit is shown an actual example of what science has done to make man indepen- dent of the weather in the production of plants. Here are plants that have been grown by electric light. Beside them are other plants grown by sunlight. The difference between them is striking; the plants that have been absorbing artificial light throughout a 24-hour day are taller, more sturdy, more mature than those that have depended entirely on the natural duration of sunlight. A few weeks ago it was announced that Scientists of the General Electric Com- pany had succeeded in developing a quan- tity production method for clear fused quartz, 65 per cent more translucent than glass, hence, an admirable substance for the manufacture of lenses, and offering medical science a way of utilizing the curative effects of light. ’ Samples of clear fused quartz are shown ‘a the various stages of its manufacture, tom rock crystals to a finished lens. This eae supplies an illustration of one of the underlying purposes of the new science uilding—to keep abreast of current Scientific discoveries, and to present them to public view as soon as possible. With this end in view, the exhibits, un- (Continued on page 112) POPULAR SCIENCE MONTHLY Filament Rheostat Variometer i oh) \ \ - # gente) ( ie AY A aad mY ROM smallest screw or binding post to con- densers, variocouplers and transformers, ea of the 130 Federal Standard Radio Parts are made to give maximum service and are backed by the iron-clad Federal performance guarantee. FEDERAL TELEPHONE & TELEGRAPH CO. When assembling your set, insist that each part be of Federal man- ufacture. ‘iS eG Boston NewYork Philadelphia Pittsburgh Chicago SanFrancisco Bridgeburg,Can. London, Eng, Buffalo, N. Y. everal MAKE MONEY-SELL RADIO! Radio offers the biggest money-making op- portunity on earth today. And the Ozarka Plan opens the door to this big opportunity. Look at the picture of this beautiful Radio Receiver. This picture was made from an actual photograph. By the Ozarka Plan that Radio Instrument can be the product of your own making—easily, simply and sure- ly. It will be yours to maie, to sell and to reap a rich reward in cash profits. No experience necessary. You need not have much cash. All you need is spare time, de- termination and action. If you’re that kind of achap, the Ozarka Plan will start you on a straight line toward a real money-making business of your own. It can be as big and as profitable as you are ambitious to make it. We want goo¢ men in every county. Ex- clusive territory is going fast. Be sure and give us the name of your county. Write to- day for the Ozarka Plan. A wonderfully in- teresting book of facts, particulars and proofs. Itis FREE. Act now. CHICAGO OZAR 7 852 Washington Bivd. 140-page Book full of life-size ruled forms, each one com- pletely filled in. The answer to problems of accounting and record keeping for any business or profession. Send for this FREE Book Today John C. Moore Corporation (Established 1839) 2145 Stone St., Rochester, N. Y. OORES systems Use In More Than = 300,000 Offices

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EARLE E. LIEDERMAN The Muscle Builder Rip Off Your Shirt and get on the job. Work up a sweat and chase those disease bugs out of you. Gee, but they're happy with the chance you're giving them. Are you going to loaf around and let them eat up all your pep. Snap out of it, fellows. You're just digging your own grave when you refuse to exercise. Sitting back in a rocking chair and smoking your old Jimmy pipe may feel fine to a lazy man, but it sure raises havoc with your chances for a long life or a successful one. WHO WILL HELP YOU? I know you think you know all about it. Most everyone you mect tries to tell you how, but they can teach an oyster how to sing quicker than they can show you anything about muscle building. If you are in legal trouble, you seek a lawyer. If you are wise you get the best, for they are the cheapest in the long run. Now, how about that body of yours? Do you realize it is the choicest possession you have on earth? Don't be a plain dumb Dora! Use your head. This is vital with you. Muscle building is one of the tricki- est studies on earth. I've worked at it ever since the day I left High School, so I ought to know. I've seen many a poor chap literally ruined by the wrong kind of guidance. On the other hand I've seen human wrecks transformed into human Hercules by being started in the right direction. VE GOT THE WORKS Come to me and I'll shoot you so full of strength and vitality you'll think it’s your birthday. I'm the man that first guaranteed one full inch on your arm in 30 days. And I'm the man who does it. I'll fill out that chest so that it will take a inan's size load of oxygen, shooting life into your blood and building up your whole body. I'll put a pair of arms and shoul- ders on you that will carry the kick of a mule. I'll shoot a quiver up your old spine and put a spring into your step so that you will feel like fighting a wildcat. This is no idle prattle, fellows. I don't promise these things—I guarantee them. You don't take any chances with me. I've got the works and I'm willing to prove it. Come on then—let’s go. d for my new 64-pa “MUSCULAR DEVELOPMENT” IT IS FREE It contains forty-three full-page photographs of myself and some of the many prize-winning pupils I have trained. Some of these came to me as pitiful weaklings, imploring me to help them. Look them over now and you will marvel at their present physiques. This book will prove an impetus and a real inspiration to —. It will thrill you through and through. All I ask is 10 cents to cover the cost of wrapping and mailing and it is yours to keep. This will not obligate you at all, but for the sake of your future health and happiness, do not put it off. Send today—tright now before you turn this page. EARLE E. LIEDERMAN Dept. 1308, 305 Broadway, New York City —eSe Se =e ee eee eee eee eee eee eee oe eee eee ae a EARLE E. LIEDERMAN Dept. 1308, 305 Broadway, New York City Dear Sir: I enclose herewith 10c for which you are to send me, without obligation on my part whatever, a copy of your latest book,‘‘Muscular Development.” a ee ee (Please write or print plainly) POPULAR SCIENCE MONTHLY _ Wonder House of Science | (Continued from page 111) | | like those of the ordinary museum, are | mobile. They will be changed about, re- moved, or replaced with every new step in scientific progress. The seismograph, the Foucault pendulum, and a few similar instruments that demonstrate funda- mental phenomena of nature, are the only ones regarded as permanent. Beside the clear fused quartz is a photo- electric cell, the contrivance used in talk- ing movies, in control of torpedoes and boats by searchlights and similar extraor- dinary inventions. There is an X-ray machine with which photographs can be made of your internal organs. This is one of the few pieces of apparatus in the building with which you | are not invited to experiment, for it re- | quires a trained operator. You will find, too, an exhibit prepared by the Smithsonian Institution—fossils, meteorites, and similar discoveries that have enabled science to peer into the dim caverns of the past and unfold to man the history of the earth, and to exnlore the wonders of the heavens. \ X 7 HAT I have given here is merely an impression of afew of the furnishings of this new home of science. There are many others, all of engrossing interest to the most casual visitor. The building itself is a palace. Art and science have joined to make it a con- spicuous addition to the many beautiful | buildings of Washington. Its construction marks the realization of a dream of Dr. George Ellery Hale, director of the Mount Wilson Observatory, who several years ago conceived the possibility of a national home for science. The gift of $5,000,000 by the Carnegie Corporation to the National Academy of Sciences and the National Research Council made the erection of the building possible. It cost $1,450,000, the remainder of the gift being reserved for maintenance. “Our aim is to assure the future of science,’’ Doctor Hale told me, “‘by sup- plying here a meeting place for pure science and its applications. We wish to give visitors a chance to peer beneath the surface of the examples of applied science they encounter in their every-day life and to see and appreciate the work in pure science that has made them possible. Thus we hope to interest many people in the fundamentals of science. Who can say that we may not awaken an interest in some—the young especially—that will | cause them to embrace careers in science?”’ This new building in Washington fur- | nishes a reminder to all of us of what we owe to science, a thought beautifully ex- pressed in the dedicatory inscription that encircles the base of the handsome dome: “To Science, Pilot of Industry, Con- queror of Disease, Multiplier of the Har- vest, Explorer of the Universe, Revealer of Nature’s Laws, Eternal Guide to Truth.’’ HE most wonderful sea story you ever have read has just been com- pleted by Mr. Brown for publication in next month’s issue. You'll find it dif- ferent from other sea stories—an en- grossing tale of science, with the tang of the salt waves and the mystery of | fathomless depths. ‘ORDS SAMile on Gallon of Gasoline bess {] _with Air Friction Carburetor Ve guarantee all other cars nearly doub) [e-Epresent mileage, power and flexibility, make hills on high formerly difficult of low. Models for any car, truck, tractor marine or stationery engine. Makes ol cars better than new. Sco wonderful _mileago et ee ord.......24mL, 9 Reo.......24 Chevro Buick 4... .20mL Buick 6... .24ml. Hudson. .. .20mt. Hupp......25mil, Dodge 283ml. strings to our guarantee. Anyone = od poke 7 a wrench can an attach it it. No ee new holes or c RicFRIeTION URETOR Co. Dayten. Ohio, U. S, 4, 1074 SOLDERS ALL 2 JOINTS pti mene STORM, KING. APPROVED BY THE NATIONAL BOARD of FIRE UNDERWRITERS 25¢ AT ALL DEALERS il | SOLDERALL CO., Newark.N.J. “DON'T SHOUT” “IT hear you. I can hear now as wellas anybody. ‘HOW?’ With THE MORLEY PHONE. I've a pair in my ears now, but they are invisible. I would not know I had them in, myself, only that I hear all right." The Morley Phone for the DEAF is to the ears what glasses_are to the eyes. Invisible, comfortable, weight- less and harmless. Anyone can adjust it. Over one hundred thoe- sand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadelphia I Made 100,000 in less than five years as a real ie special- ist. Started during my spare time, with no experience and less than $5 capital. If you want to learn the secret of my success and follow my money-making method, send your name and address at once to American Busi- ness Builders, Dept. A-348-A, 1133 Broad- way, New York. T hey send full information free, telling you how you can build up an in- dependent, profitable business of your own by using my amazingly successful system. res on latest type of Revolver; appesrance —— It takes standard .22 tainable everywhere. — express, SOc per 100, oo Co., Dept. 156, Racine, t

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early doub! flexibitity, difficuls on uck, tra Makes oid hundred thoa- , Philadelphia )00 e special , with no 1. If you ccess and send your can Busi- 3 Broad- ormation up an in- your own | system, ISTOL PRICES 50¢. $12 post- PAID POPULAR SCIENCE MONTHLY GET A HOBBY MAKE MODELS Start a Home Workshop “Model Making,” by R. F. Yates, de- scribes the construction of gas-model engines, steam-engines, locomotives, boats, dynamos, turbines, railroads, guns, etc. Thirty chap- ters are devoted to models of various nature. It will help you to become a better me- chanic. It will help you to do hard soldering, soft soldering, lathe work, tempering, drilling, pattern-making, etc. This is a book every amateur or professional mechanic and model maker should have. “Model Making”’ describes real engineering models, not toys. 400 Pages, 300 Illustrations. complete, easily understood. paid, $3.00. Popular Science Monthly 225 West 39th Street New York Practical, Price, Post- TWENTIETH CENTURY Recipes, Formulas and Processes Bg book of 800 pages is the most com- —_ Book of Recipes ever published, giving thousands of recipes for the manufacture of valuable articles for every-day use. Hints, Helps, Practical Ideas and Secret Processes yes every branch of the useful arts are 10,000 Practical Formulas—The Best Way to Make Everything win book to which you may turn with confidence pry ot ou will find what you are looking for. A mine tains ormation, up-to-date in every respect. Con- an immense number of formulas that every o ; - —— to have, that are not found in any other Price $4.00 Popular Science Monthly 225 West 39th Street, New York How to Build a Small Home for Less Money (Continued from page 63) be added later when you can afford it, and its omission should save from $550 to $750 in the initial cost. If you decide you need a basement, there is a chance to save from $75 to $125 by omitting partitions for laundry, heater room, etc. These can be added at any time. In the kitchen a very large item of ex- pense lies in built-in fixtures, which cost anywhere from $125 to $350. Good ready- made kitchen cabinets usually are cheaper and will give very satisfactory service. A stock refrigerator, instead of a built-in refrigerator with waste and platform, will save you from $20 to $40. Omission of a clothes chute will save possibly $25 more. In selecting plumbing fixtures for the kitchen, you will find that durable enameled iron is less expensive than china- ware. A wooden drainboard for the sink will cost less than an enameled iron drain- board. Separate faucets will be several dollars cheaper than combination hot and cold water faucets. In the bathroom, too, considerable sav- ing can be made by using enameled iron instead of porcelain for bathtub and lavatory. For the lavatory the saving may be at least $30. A simple bathtub with legs usually is about $40 cheaper than a recess tub. While tile flooring for the bathroom is desirable, you can get along very well without it, thus saving an expense of at least $30 or $40. Of course, every one wants a cheerful fireplace in the living-room; but do you need it? Here is a chance to save prob- ably $350 in labor and material. I have mentioned here just a few of the outstanding points that present oppor- tunities to cut costs. There are dozens of other items, such as built-in china closets, bookcases, wardrobes and closets, that may be eliminated without sacrificing comfort and happiness. Then, too, there is a great chance to cut expenses in selecting materials for the _ interior construction. Stock doors, moldings and sash, for ex- ample, will cost less than those of special sizes and special design. Again, the use of a medium grade of oak flooring instead of first grade wood is likely to represent a saving of $100 on your home. For the wood trim, too, soft wood is less expensive than hard wood. Fir or pine, if painted, will be attractive and will give excellent service, while saving you anywhere from $125 to $175. Then in your selection of plain electric fixtures and hardware, which are in the best of taste, you should be able to save at least $200. And so you can go through your build- ing specifications, studying every item of material, equipment and labor for a chance of reducing its cost without im- pairing its usefulness. In almost every clause you will find some element, small or large, that represents an unnecessary financial burden. Cut it out. In the end you will be surprised at the total amount you can save in building your home. Another useful and _ informative article on home-building will appear in the September POPULAR SCIENCE MONTHLY, chool ai " gE rE : een WicH scHooL COURSE IN | A RALUL YOu ARE BADLY if you lack HANDICAPPED LighSchool training. You cannot attain business or social prominence. You are barred from a successful business career, from the leading professions, from well- paid civil service jobs, from teaching and college entrance. In fact, em- ployers of practically all worth-while positions demand High School train- ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you. FIT YOURSELF FOR A BIG FUTURE This course, § which has been prepared by some of § America’s leading professors, will broaden your mind, and make you keen, alert and capable. It is com- § plete, simplified and up-to-date. It ¢ covers all subjects given in a resident school and meets all requirements of a High School training. From the first lesson to the last you are care- fully examined and coached. USE SPARE TIMEONLY Most people idle away fifty hours a week, Probably you do. Use only one-fifth of your wasted hours for @ study and you can remove your & present handicap within two years. § You will enjoy the lessons and the § knowledge you will gain will well § repay the time spent in study. = Check and mail the coupon NOW r } for full particulars and Free Bulletin, American School Drexel Ave. and 58th S$f., Chicago American School Dept. HC75, Drexel Ave. & 58th St., Chicago Send me full information on the subject checked and how you will help me win success. aceon Architect wee Lawyer ae Building Contractor «sss. Machine Shop Practice iad Automobile Engineer seee.Photoplay Writer pees Automobile Repairman «+. Mechanical Engineer saan Civil Engineer «ose Shop Superintendent ciate Structural Engineer «+. employment Manager -.....business Manager __..... Steam Engineer aeases Cert. Public Accountant _......Foremanship -....Accountant and Auditor ...... Sanitary Engineer ennes Bookkee per «Surveyor (& Mapping) «sees Draftsman and Designer _...... Telephone Engineer omese Electrical Engineer «-.... Telegraph Engineer énenes Electric Light & Power _......High School Graduate «....GeneralEducation ....... Fire Insurance Expert oeeeVOcational Guidance _»=........ Wireless Radio eoeeeBusiness LAW hase Undecided Name Addr

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114 USE-!IS THE TEST Build Your Radio Set With Kellogg Guaranteed Parts ELLOGG Dials add to the beauty and efficiency of every set. They are of molded Bakelite, of reinforced construction. The calibrations are clearly and accurately marked. The large knob is shaped and corrugated to fit the fingers making possible the slight- est movement. The steel dies for molding Kellogg dials are mathe- matically correct, assuring exact mounting center, so that the dial turns absolutely true, a require- ment of every “finished” radio set. Buy Kellozg Parts and you know your set will be good. If your dealer does not handle Kel- logg communicate direct with us. Kellogg Switchboard & Supply Company 1066 W. Adams - CHICAGO USE—-!1S THE TEST POPULAR SCIENCE MONTHLY rom t eR ‘laboratory s pal a. \This 52 page Book escribes how to make \\OKNOCKOUT y/-\_ Radio Fao Receivers B. R. Linton, Hapeville, Ga., using the 1-tube Knockout set described in this book, hears KFI, Los Angeles and many other distant stations reg- ularly on his loud speaker. YOU, too, can build a Knock-out distance-getter. This book tells you how! No “‘trick’’ circuits; each of the sets has been built and tested in the Radio Broadcast laboratory —where all new circuits are tried out—under the personal direction of Arthur H. Lynch. The 9 Knock-out sets de- scribed in this book were chosen because of the excep- tional results obtained with them by hundreds of Radio Broadeast readers. You can buy all of the parts from your nearest dealer. The first edition of Radio Broadcast’s Knock-out series was sold in less than 10 days. The second edition—more data, more photographs— is going fast. If your dealer can- not supply you, use the coupon today. If dissatisfied we will refund your money. RADIO BROADCAST, Doubleday, Page & Co., Garden City, N.Y. I enclose 50 cents in payment for a copy of Radio Broadcast’s Knock-Out Series to be sent to Telepathy Put to the Test (Continued from page 32) room knew what commanas I would give. In a very short time after the start he arrived at the desk, picked up a number of objects repeatedly and threw them down again nervously. For instance, he picked up a letter three times, struck or tapped the desk with it, and swung it up and down each time he took it up, as you or I might do absent-mindedly. Then he passed on with an air of aimlessness to the next object. At last he reached the box of matches. First he picked up the entire box and threw it down again; he took out a single match and tossed it back; another he took up and tapped the desk with it; a third, after being tossed in the air a moment, was used to poke the others in the box. Then he took up a match with an air of decision; whereupon I “thought” the next command which was, as I said above, to carry it to the little table on which were the water pitcher and the inverted tumblers. After a great many more apparently “try, try again’? movements, he put the match into a tumbler, shook it about, took it out as if he believed he had done the right thing, and set about obeying my next and last command, which was to go across the room to the telephone stand and to place the match upon the stand beneath the instrument. Here were more “‘try, try again’? movements, and at last a decisive act that successfully com- pleted the experiment. ERTAIN features of behavior of those who obey ‘‘mental commands” and who “find things,” suggest the hypothesis that the experimenter himself, wholly without intention and quite unconsciously, makes signs that are observed and in- terpreted by the “‘telepathist’’; signs that guide him in the way he should go and that tell him when he has finished. For example, in the experiment I have described, I may have caught my breath involuntarily when my _ subject was dabbling at the match box and at the inverted tumbler. When he was ap- proaching the box, I may have inclined my body forward ever so slightly or drawn back, according as I wished him to succeed or to fail, precisely as my neighbor on the bleachers at a football game unconsciously pushes toward me or away from me according as he wishes or expects the team to drive this way or that. Now the hypothesis is that the ‘“‘tele- pathist” in the case I have cited caught just such movements, or analogous move- ments, on my part—my facial expression, the sounds of catching my breath, and other involuntary signs from which he drew the inference that he was on the right or the wrong track. His frequent repetition of a movement, such as picking | up and throwing down a letter, may | be interpreted as ways of “fishing” for a repetition of my signs of approval or disapproval. Of course, my subject’s eyes were not directed toward me, but I was always in position, a little behind him and toward his right, so that he could see me out of the tail of his eye. Such a condition af- fords, as every student of vision knows, an excellent opportunity for detecting small movements. The reader can easily satisfy himself upon this point if he will hold his index finger steadily at the side of one eye and so far back toward the tip of the ear that it is just invisible. Now let him wag his finger and immediately it becomes visible only to be ‘‘out of sight’ again | once he holds it quite still. | The fact is that probably all of us have far too mean a conception of the capaci- ties of human nature for detecting slight sensory impressions and small differences among gross impressions. Consider the ability of the blind to make their way from place to place among obstacles, guided by slight differences of air move- ment against their cheeks, by the feel of the ground beneath their feet, and pos- sibly by the faintest auditory cues. And let us not forget too, the totally deaf per- son who understands what you are saying so long as he can hold his hand upon your head or shoulder or upon the back of your neck. Such considerations as these led me to make another test of the remarkable abilities of the so-called telepathist. This time a five-cent piece had been hidden in an overshoe worn by one of the observers. If the subject should find the coin, he was to about-face and throw it against the door at the opposite side of the room. For my part, I was determined to check my in- voluntary movements while attention was riveted sharply on the things the subject should do. The result was that it took the subject three-quarters of an hour to find the coin. And he never succeeded in throwing it against the door. 7" of course, is not absolute proof of the efficacy of my own involuntary movements as signs to the subject, but it does certainly strengthen the hypothesis I have advanced. Once more, it is not impossible that hearing may play a part in some instances that pass for telepathic communications. Many a person will discover that when he is thinking his vocal apparatus is at work. He is incipiently speaking. This is espe- cially true when he is closely attentive to what he is thinking. Some people have reported that their throats are tired after having listened for an hour to a lecture or to a concert. They have been incipiently saying the words of the speaker after him or singing after the vocalist. Inevitably such action of one’s vocal organs will set in motion a column of air in the mouth and nasal cavities. These vi- brations will be communicated to the air exactly as in normal speech, and a suffi- ciently sensitive ear could catch them. In the foregoing examples we have con- sidered only alleged telepathic communl- cation or transfer of thought between persons physically close to each other. What is to be said of communications of the sort where great distances are In- volved? | Recently Dr. Gardner Murphy of | Columbia University, Dr. H. B. English (Continued on page 115) —— Tel of Al took com! ratec Chic ment that dene Tr mere publi had static atten it we trans of: iB thou: by t | they | 664. rect. 2 fore 1 ital 1 Two and J Tas ally « 3. color the ¢ and | is sor ing t! | all pe the c ently 4, food. “heet 5. Wher repor beloy right on h for ¢ pure] 6 trans scene of a firen Agai attra So have Tema lister anyt ment In expe! this Stan yield Tesul agem few } appli In wl Di of * carn Show ical

Page 117

af- 1all isfy his eye ear vag nes ‘ain ave aci- ght 1ceg the way ‘les, yve- 1 of DOS- And per- ying ‘our : of e to able lhis n in ers. was the For y in- was ject took r to din of of tary ut it nesis that neces ions. n he york. 2s pe- ye to have after re or ently him vocal air in e vi- e ail suffi- - con- nuni- ween ther. ns of e in- y of | iglish Telepathy Put to the Test (Continued from page 114) of Antioch College, and the writer under- took a test of the reality of telepathic communication at a distance. We ope- rated from the Zenith Radio Station in | Chicago. We went at it frankly as experi- | mentalists and with no predetermination that we should find any given sort of evi- dence either for or against. The radio was used in this instance merely to make our announcements to the public at large. A week before the test it had been made known from the radio station that such an experiment would be attempted. So on the evening of the test it was announced that those around the transmitter in Chicago would be thinking of: 1. A number between one and one thousand. Listeners were asked to report by telegraph or mail what impressions they received, if any. The number was 664. Of 2010 replies none was cor- rect. 2. An animal illustrated on a chart be- foreus. Above it on the chart was a cap- ital letter. What animal and what letter? Two persons correctly reported a walrus and nineteen were correct in reporting “S.”. Each of these is below the theoretic- ally chance figure. 3. Two intersecting lines, one of them colored. What was the color and what the angle of intersection? Two hundred and fifty correctly reported yellow, which is somewhat below a chance result, assum- | ing that the colors of the rainbow include | all possible choices. The angle formed by the crossing lines was about 73°. Appar- ently no one reported this rightly. 4. The senders were eating a certain food. What was it? No one answered “beets.” 5. Each sender was sufiering pain. Where was it located? Only three correctly reported the palm of the left hand just below the little finger. Two were nearly right. Taking 76 arbitrarily chosen areas on hands and arms as affording material for choice, we again were dealing with purely chance results. 6 and 7. Here the attempt was to transmit the impression of an emotional scene. We were looking upon the picture of a drowning man and upon that of a fireman rescuing a child, respectively. Again there was nothing in the return to attract attention. So far nothing but negative results have come from the experiment, and it remains to be seen whether any of the listeners who replied correctly will yield anything of interest under further experi- mentation. In fact, the systematic and extensive experimental work that has been done in this connection by Doctor Coover of Stanford University and others has yielded such overwhelmingly negative results that the field offers little encour- agement to stimulate more than a very few research students. This observation applies particularly to those situations in which distance is a factor. Did you ever win one of the games of chance and skill” at a traveling Carnival? In an early issue an éx- showman will reveal cunning mechan- ical tricks of the carnival gamester. POPULAR SCIENCE MONTHLY KONy at Ss ai >r, got fe ( The Ideal TUBE ie for Vacation Time T the seashore—in one of our great national parks, or while motor- ing you will find the Cunning- ham Dry Battery Detector and Am- plifier, Type C-299, the ideal Tube for your portable receiving set. The special filament of this tube hav- ing a current so low that it may receive its supply from standard No. 6 Dry batteries or even from ordinary flash- lizht batteries, makes possible this entertaining application of Radio in places far remore. Your dealer can give you useful sugges- tions for the purchase or construction of a highly efficient and practical portable RadioSet. Make this a Radio summer. Cunningham C-299 Detector and Amplifier Tube C-299 3 volts .06 amp. Dry Battery Detector and Am- plifier - * *= #= $5.00 Other Cunningham Radio Tubes C-301A—6 Volts 1-4 amp. Am- plifier - - - - - C-3 0—6 Volts Gas Content De- tec’or - - - - - C-11—1.1 Volts .25 amp. Dry Rattery Detector and Ampli- er, Snecial Base- - = - C-12—Similar to C-11 with Stan- dard Base - »« = - $5.00 $5.00 $5.00 . Cunningham tubes ere Patent Notices covered by patenta dated 2-18-08, 2-18-12, 12-30-13, 10-23-17, 10-23 17 and others issucd and pending. Licensed for amaterr, experlmental and entertainment use in radio commun cation, Any other use will be an infringement. Cunningham 40-page Data Book fullv explaining care and operation of Radio Tubes now availuble by sending 10c in stamps to San Francisco office. AS Leu ye ° 182 Second Street Branch Home Office: Branch CHICAGO SAN FRANCISCO NEW YORK BE YOUR OWN FIXER WITH SMOOTH-ON No.l —and save your re- pair money for big- ger things. Cracked heating boilers, radiators,wa- ter pipes, tanks, leaky ovens, fur- naces, stove pipes, loose handles, leaky automobile radiators, hose connections, gas tanks, cracked water jackets and gear cases, loose nuts, grease cups and hub caps are usually a snap to repair with Smooth-On No. 1 —and with a saving of anywhere from 25c to $25.00 each time. Get a 6-oz., 1, 5 or 10-lb. can of Smooth-On (from any live supply store). The repair booklet which we send free if you mention this magazine, will nelp you to get good results, SMOOTH-ON repain |SMOOTH-ON MFG. CO. BOOK Dept. 58 574 Communipaw Avenue Jersey City, N. J. \S —this is some tool OU can take your choice—one model, No. 11, has three screwdriver blades, the other, No 12, has a keen steel knife blade and two screwdriver blades. Both models work just the same, and with both of them you can CHANGE BLADES INSTANTLY. All blades are selected and produced by gravity action, the blades can never be lost, the knife blade can never fold or turn and injure you. Beautifully made, the handiest tool you ever saw for a thousand uses. Handles blued to prevent rust. Model No 11 for $1.80, and No. 12 for $2.25. Send money order or your check and we will ship post prepaid at once. Each tool guaranteed. Your money refunded if not satisfied. © Dealers are requested to write for information on these tools and the Simore Automatic Try-Square THE SIMON & SKIDMORE MFG. CO. Dept. 5-8 Santa Ana, California

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WURENZER vm i | er _ 200 Years Ago 3.x0n town i) oo: ; of Shoeneck lived Hans Adam ne | ON Wurlitzer, Master Violin Maker. | His shop was a gathering place for ‘ mrosistons of ¢ the time, for he was , @ true craftsman. When he died his shop passed into the hands of his eldest son, and for seven generations, down Wurlitzer’ have carri his work. In every Warlitzer instru- ment vou will find a quality a character, that could not * come from mere excellence Ss of manufectare. It is the heritag: ese seven \ weperetioas of music craftsmanship. Warlitzer Instrument, in your Own Home OU may now have any Wurlitzer instrument for a week’s free trial in your own home. Examine the instrument, show it to your friends, play it as much as you wish. No obligation to buy — no expense for the trial. We make this liberal offer because we want you to see for yourself the superior } quality of Wurlitzer instru- ments, the result of 200 [yey years’ experience in musical [¥ instrument building. re Artists of the highest standing in every sphere of music use 4 Wurlitzer instruments and _ re- g@ ce ge them to others. They ak especially of the ease of - aying, a feature that is of im- portance to the amateur as well as the professional. > Easy Payments \ If you decide to buy after the/| @ week’s free trial, payments are arranged in small ‘monthly sums. | | A few cents a day will Ay* for your instrument. Special offers on complete sethte--selent lined case, ail accessories, eelf-instruc- tor, ‘etc. — everything you need at practically the cost of the instrument alone. Send for New Catalog @ The greatest musical catal ever published! Over 3, articles — every known in- ment described and illus- trated; many of them shown in full colors. Gives you lowest prices and all details of Free Trial, Eas Payment plan. All sent FREE — no obligation. Send this Coupon oo RUDOLPH WURLITZER CO., Dat. ern 120 W. 42ndSt.,NewYork 117 E. 4th St., Cincinnati 329 S. Wabash Ave., Chicago 250 Stockton St., San Francisco Send me, absolutely free, your new Illnstrated catalog, with rices and description of every known musical instrument. Also ll me how I may try any instrument in my own home and pay for it in small monthly sums. No obligation. " (State Instrument in which you are interested) yy Copsright, 1924, The Rudolph Wurlitzer Co. | ground post 2. POPULAR SCIENCE MONTHLY Building a Five-Tube Loop Set (Continued from page 66) winding are connected with their cor- responding switch points in order. The top end of the winding also is con- nected with terminal B of jack 4. Ter- minal C of jack 4 is connected with the Next, run a wire from | terminal D of jack 4 to the B (rotary | wire from binding post 31, | baseboard just in front of the F terminals plates) terminal of condenser 8, and an- other wire from the switch arm of switch 6 | to the slider terminal B of potentiometer 7. Connect these two wires by a short length of wire. Another wire then can be used to connect terminal A of jack 4 with the A (stationary plates) terminal of con- denser 8. This wire is connected with the G terminal of socket 10. The wiring of the tuning unit is completed by connect- ing the switch arm of switch 5 with the aerial post 1. Next, begin the filament wiring by connecting binding post 30 with A ter- minal of switch 25. Then connect, in the order named, B terminal of switch 25, B terminals of rheostats 24, 19, and 15, and C terminal of potentiometer 7. Run a along the of the sockets, to terminal 11. This wire | will extend practically the length of the baseboard. Short lengths of wire are used to con- | nect this wire with the following termin- | als: The Fi terminals of sockets 10, 14, 18, 23, and 28; A terminal of potentiom- | eter 7; one terminal of fixed condenser 9; | transformer 16; F terminals of variotransformers 13 and 16. If dry-cell tubes are used, F terminal of transformer 13 should be connected with negative A-battery lead. The A terminal of rheostat 15 is con- nected with F>2 terminals of sockets 10 and 14; A terminal of rheostat 19 with the F2 terminal of socket 18; A terminal of rheostat 24 with the F> terminals of sockets 23 and 28. ONNECT P terminal of socket 10 with P terminal of transformer 13. The B terminals of transformers 13 and 16 and the remaining terminal of con- den*er 9 all are connected with terminal 12. The G terminal of transformer 13 then is connected with G terminal of socket 14; P terminal of socket 14 with P terminal of G terminal of trans- | former 16 with A terminal of grid con- | denser and leak 17; B terminal of grid condenser and leak 17 with G terminal of socket 18; P terminal of socket 18 with A terminal of jack 22; P terminal of transformer 21 with B terminal of the jack; B terminal of transformer 21 with C terminal of the jack; D terminal of the jack with terminal 20. Next, connect A terminal of jack 27 with P terminal of socket 23; B terminal of jack 27 with the P terminal of trans- former 26; C terminal of jack 27 with B terminal of transformer 26; D terminal of jack 27 with B terminal of jack 29 and with terminal 32. Connect P terminal of socket 28 with A terminal of jack 29; G terminal of trans- former 21 with G terminal of socket 23; G terminal of transformer 26 with the G terminal of socket 28. t A standard 414-volt C battery can be placed between sockets 23 and 28 and the back edge of the baseboard. The positive terminal of the battery should be cop. nected with the B terminal of rheostat 24 Connect A terminals of transformers 2} and 26 and connect them with the nega. tive 414-volt terminal of the C battery, Insulated wires to serve as battery leads then are soldered to terminals 11, 12 20, and 32 to connect the terminals with the B battery. If a soft detector tube js used, the lead from terminal 20 should be connected with a B-battery voltage of 221% volts or less. If hard tubes of the UV-199 or UV-201 A type are used throughout, the No. 20 terminal should be connected with a B-battery voltage of from 45 to 67 44 volts. Terminal 11 should be connected with the negative termina] of the B battery. Terminals 12 and 32 should be tried on various voltages from 45 to 90 volts until best results are obtained, The positive A-battery lead should be connected with binding post 31, while the negative A-battery lead should be con- nected with binding post 30. The novel arrangement of aerial and, ground posts and tuning unit in connec. tion with jack 4 makes it possible to use outdoor, indoor, and loop aerials with the set in various ways. Usually if an outside or indoor aerial of the ordinary single- or double-wire type is used, the aerial is connected with the aerial post 1 and the ground wire with ground post 2. HEN a loop aerial is used, one ter- minal of the loop may be connected with aerial ppst 1 and the other terminal with post 2. The switch arm of switch 6 _may be set on the “blind” contact X of switch 6 to disconnect it from the coil. A number of turns of coil 3 can be con- nected in series with the loop to aid in tuning by setting the switch arm of switch 5 on the various switch points. The loop may be used without any por- tion of the coil by connecting the two ends of the loop with the terminals of an ordi- nary phone plug, inserting the plug into jack 4, and setting the switch arm of switch 6 in the “blind” contact X od switch 6. In tuning the set, the rough adjustment | for wave length is obtained by setting the switches when an outdoor or indoor aerial is used and by adjusting the variable con- denser. The finer adjustments for wave length are obtained with the variotrans former dials and the Vernier plate of the variable condenser. Control of destruc tive regenerative effects is obtained by at- justment of the variotransformer dials, rheostats, and potentiometer. If properly constructed, a receiver this type should give more ‘efficient rag tion with greater freedom from static and interference when used with a loop short indoor aerial, than a highly efficient three-tube set will give when used with a very good outdoor aerial system. N RESPONSE to many requests - I our readers, Mr. Calcaterra’s article | in next month’ s issue will describe how to build a remarkably sensitive supe heterodyne receiving set. an ch wi Cc St ar th ti Bt vi nH Fy BHNCoM Lae} . # i :

Page 119

and the Ositive IE COn- | stat 24, ners 2] € nega- ittery, battery 311,12, ls with tube js ould be tage of ; of the e used should ltage of should erminal and 32 from 45 »tained, ould be hile the be con- ial and, connec- > to use vith the 1erial of type is ith the re with one ter- nnected erminal switch 6 ct X of coil. A be con- ) aid in arm of ints. iny por- wo ends an ordi- lug into arm of t Xe } ustment | ting the or aerial ble con- or wave “jotrans- e of the destruc d by ad- or dials, | eiver of t opera: atic and loop o efficient ed with 1. ts from | _ article, ibe how super ——

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«Most Terrible Invention”’ (Continued from page 34) electrical conductivity increased by as much as several million times. And so a beam of ultra-violet light sufficiently powerful would have just the effect that is claimed for the carrier beam. It would form a conducting path for the transmission of powerful electric currents through the air. Perhaps this is not exactly what the carrier beam is; but it is what the carrier beam might be. Many experts who have studied the Grindell- | Matthews’ experiments and those of other

inventors are of the opinion the secret lies in some application or modification of this ionizing power of the ultra-violet rays. T PRESENT the claims of the several inventors have attracted public interest largely from the standpoint of the possibility of their use in warfare. A beam directed against an unprotected war-ship might succeed in exploding its ammunition or damaging its operating mechanism. Similarly, conceivably, such an invention might be effective against air- craft, although two carrier beams would be necessary, one to carry the outgoing current, the other to serve as a return path to the ground. However powerful such beams may be, it is also possible, as the British Air Ministry pointed out in pronouncing the Grindell-Matthews ray harmless, to pro- tect war craft more or less perfectly against such a ray. All that is necessary, Mr. Grindell-Matthews himself admits, is to shield the magneto and engine with a inetal cover. To protect an armored automobile the car could be surrounded with a metal shield and a metal chain or flexible cable dragged along the ground to connect the shielding metal with the ground. It has been demonstrated that unques- tionably a ray can be developed and shot out for short distances with un- known possibilities of destructiveness. But whether such a ray can be put to use as to be an effective and deadly agency in warfare has not yet been proved. And even should such a beam, when fully de- veloped, have the grim potentialities in- ventors claim for its use, the result un- doubtedly would be an inventive struggle between offensive use of the ray and de- fensive protection appliances. (yas possibilities of such a device, however, involve real creative work for mankind. For example, the old dream of wireless power transmission, suggested so often by Nikola Tesla, a man to whom Mr. Grindell-Matthews gives credit for having been the inspiration of his investi- gations. If such beams can be used to explode powder or deal electric death, they can be used also to carry power from one point to another without wires. Also they can be used in burglar alarms and similar devices for protecting prop- erty. Imagine, for example, the necessity of protecting a government warehouse against unwarranted entry. Four ultra- violet rays, each charged with high- voltage current might be arranged to (Continued on page 118) ah

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| | | | _ barrage. | Mr. Grindell-Matthews or any other in. a ‘‘Most Terrible Invention” (Continued from page 117) make a fence around the four sides of the plant at about the height of a crouching man. No man would find it healthy to | attempt the passing of such an invisible It is far from certain, of course, that | ventor actually has solved the problem of

| sending such power rays over considerable distances. The experiments reported 80 far have involved distances of only a few feet. If some variant of ultra-violet light js really the secret of the carrier beam, one of the main difficulties to be expected j in using it is the absorption of the rays by | the air. This means that the beam yill| become rapidly weaker, and experiments | that are successful enough over short | distances may not be so striking when | the distance is increased to many yards | or to a few miles. HESE questions can be answered, of | course, only by further experiments, | Such experiments are reported to be in | progress. But with the many peacetime | uses of such rays, including, for example, | the recent experiments in Paris on the use of ultra-violet light as a cure for can- | cer and the possibility already suggested | tors, Westinghouse Electric and Manv-

| that the charged ray of Mr. Grindell- | Matthews may prove still more beneficial in this disease, it is probable that power. | charged rays of some kind will play an important réle in the science of the next 10 years, even if their use in distant warfare proves to be impracticable.

Recent Publications A résumé of new books on science and | invention The Depths of the Universe, by Dr.| George Ellery Hale, honorary director of | the Mt. Wilson Observatory. Three| absorbing popular essays on the wonders | of the heavens. Illustrated. Charles| Scribner’s Sons. The Romance of a Living Temple, by Frederick M. Rossiter, B.S., M.D. An interesting popular study of the human body. George Sully & Co. Super-Power as an Aid to Progress, by Guy E. Tripp, chairman, board of direc- facturing Company. A_ collection of articles and public addresses. Illustrated. G. P. Putnam’s Sons. Popular Research Narratives, edited by Edwin E. Slosson. Fifty stories of dis covery, invention, and research collected | by the Engineering Foundation. aa liams & Wilkins Co. The Einstein Theory of Relativity, m1 Garrett P. Serviss. Many phases of this| little understood subject made plain by |

graphic comparison. Illustrated. Edwit| § Miles Fadman, Inc. Science, Old and New, by J. Arthur) Thomson, M.A., LL.D., professor of nat- ural history, University of Aberdeen. A collection of essays on biological subjects by the editor of ‘‘The Outline of Science.’ G. P. Putnam’s Sons. Eyeless Sight, by Jules Romains. Cat we learn to see with our skin? G. Putnam’s Sons. —

| Here Q 1. It with t] averag which rock W foot of 2. The | that is an equ the fat | Sir Isa | action | action: 1/3. Po There cules d The m | contai i the cu 14. M: others gaseou an int a littl light with ¢ 5. Ox: Oxyge the kr believ way t whole iron, this. 6. Al its sec ing 1 tions. woulc the ey 7. W one | denly This: of el anotl 8. Hi of th piece tiny rapid they 5: 4 breat Ther and | gen, of th 10. ] It is enou into 11. call from thicl part ting from gray whe! of si the » insid Poss 12. whe) The and the 1

Page 121

—_ on” | of the ching | hy to Visible | ’ that er in. | lem of | erable ted so a few ight is | N, One | ted in | ays by | m will| iments | short when | yards | | | red, of ments, . be in cetime ample, on the or can- gested rindell- neficial power- | lay an| ne next distant 2. S ce and | by Dr.| actor of | Three | vonders | Charles | yple, by D. An human ress, by »f direc- Manu- tion of strated. lited by of dis- ollected 1. Wil vity, by s of this | olain by Edwin Arthur | r of nat-| leen. A subjects | . | science. | is, Can » G. Bl —— | m9. They breathe the water. When we Is cmaecinetitoe _ Here Are Correct Answers to Questions on Page 57 1. It is the weight of a body compared with the same weight of water. Thus the average specific gravity of rock is 2.77, which means that a cubic foot of average rock weighs just 2.77 as much as a cubic ‘foot of water. 2. The force that starts the shot forward, that is, the force of the explosion, exerts an equal force backward. This is one of the famous laws of motion discovered by | Sir Isaac Newton; the law that for every | action there is an equal and opposite re- | action. | 3, Possibly, but it has never been done. | There are always a few detached mole- cules drifting around in it as gas molecules. The most perfect vacuum ever made still | contains about eight billion molecules to ) the cubic inch. 4, Mainly because some are hotter than others. The hottest ones contain certain gaseous chemical elements that shine with an intense white light. The stars that are a little less hot shine with a yellowish light and the coolest stars of all shine with a reddish light. 5. Oxygen, the same gas that is in the air. Oxygen makes up nearly 50 per cent of the known rocks of the earth. This is not believed to be true of the earth all the way through. If you take the earth as a whole, the commonest element is probably iron, though there is no way of proving this. 6. All of the fluids in the body and all of its secretions are more or less salty. Liv- ing matter is accustomed to salty solu- tions. If the tears were not salt, they pe hurt the delicate membranes of the eye. 7. When a great many electrons pile up in one place, they are likely to jump sud- denly to some other thing that is close. This makes an electric spark. It is billions of electrons jumping from one place to another. 8. Heat is due to the very rapid vibration of the atoms of matter. For instance, a piece of iron is hot when the billions of uny iron atoms in it are vibrating very rapidly back and forth. It is cold when they are not vibrating so rapidly. breathe we get oxygen out of the air. There is also oxygen dissolved in water and the gills of the fish take up this oxy- gen, just as our lungs take up the oxygen of the air. 10. Fog is simply cloud close to the earth. It is formed whenever moist air gets cool enough to condense its water molecules into small drops. it, The gray matter, or what scientists call the “cortex.” This is a thin layer, from one-tenth to one-quarter of an inch thick, spread over the surface of the upper part of the brain. The thing that dis- ringuishes man and the higher animals tom the more lowly ones is that the ny matter is on the outside of the brain, . ere it has room to grow. In the brains a snakes, frogs and other lower animals the thinking part of the brain is on the inside, where a Possible. any great growth is im- 12. So that he will be seen less easi asil aoe he hides in thickets of tall one. “ ? Stripes look so much like the lights : shadows on the blades of grass that € tiger is very well concealed. POPULAR SCIENCE MONTHLY ere ee atalino on gn ROMO The world’s On this machine is a name plate bearing the monogram of the General ElectricCom- pany—the same monogram that is on the little motors that run labor-saving household machines for you. This mono- gram is more than a trade mark; the let- ters G-E are the ini- tials of a friend. biggest coal saver This is the largest hydro-elec- tric generator in the world; one of three new giants in- stalled by the Niagara Falls Power Company. Two mil- lion people share in the in- creased electric light and power supplied by these great generators. Each of these machines will save the equivalent of 700,000 tons of coal a year. GENERAL ELECTRIC ef Role’ ¥=t4| Protect Your Tools FREE? “ Super-Heterodyne—Neutrodyne! wi th = NW OIL: New complete Branston Kits Including Oscilla- 9 Your valuable tools can be protected absolutely from tor Coupler, Antennae Coupler, 3 Inter. R. F. rust. 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rw Lae 3 SIAL When you tank up with gas for that long trip ask the garage- man about the handy 5-Minute Vulcanizer. He will tell you that he never dreams of traveling country roads without carrying the convenient Shaler for emer- gency roadside repairs. Take atip from him. He knows from experience that vulcanized patches are the only ones that last. 8 6 oblong for cuts and Complete tears) packed in a small ° box ready tocarry Outfit in your car foran emergency. All CostsOnly garages, auto ac- $1.50 cessory and hard- Slightly higher in Canada and Far West. : NY A. SHALER CO.,2104 Fourth St., Waupun, Wis. POPULAR SCIENCE MONTHLY SN S MINUTE VULCANIZER %, Ask Your Garageman When You Stop for Gas! Don’t forget—there’s no sub- stitute for the Shaler for fixing tube punctures because there’s no substitute for vulcanizing with heat. It’s quicker than changing tubes—and so much easier than sticking on tempor- ary cold patches that soon loosen and come off. That’s why more than two million motorists use it and recommend ittotheir friends, How It Works The Shaler is very simple and easy to use. A special Patch-&- Heat Unit is used for each repair. Each Unit consists of a metal pan containing solid fuel, with a piece of raw rubber attached under- neath. Simply clamp a Unit over the puncture, and light the fuel. After five minutes take off the pan 4 and throw it away. That’s all. The tube is ready touse. It’s vul- canized—as good as new. The Complete Outfit includes the handsomely nickel plated vulcenizer and 12 Patch-&-Heat Units (Ground for punctures and ware stores carry the 5- Minute Vulcanizer in stock. Get one for yourcar, XX jy ART COLOR PRINTING CO., NEW YORK aT Nature’s Super-Power Plant (Continued from page 25) For example, not long ago lightning traveled down the elevator cable of , mine 2000 feet deep. Two miners wh, were preparing a blast were injureg severely when a charge of dynamite was exploded by the flash, and 25 others g the other end of the tunnel were shockeq About a year ago a man in one of the ‘New England states, running for shelte from a sudden storm, saw a sudden blind. ing flash followed immediately by , terrific crash of thunder. Then he was conscious of a peculiar numbness in his body. That he had been struck by light. ning, though, did not occur to him unti he noticed that his shoes had been tom from his feet. A somewhat similar case is that of a. man who was struck while standing under a tree on a farm in New York sever] years ago. He was knocked unconscious, | one arm was broken and he was badly | burned. Strange to say, he was abs & lutely naked when he was found and the field about him was strewn with bits of | his clothing. Cece recognizes several kinds of lightning, although authorities differ as to whether some types are not identical and merely appear different because of the peculiarities of human vision. Zigzag or forked lightning is the most common type. The irregular path of the discharge is believed to be due to the presence of solid particles and electrical charges that make a_ jagged course along the path of least resistance. Sheet lightning, which illuminates large areas of the sky without storm, is generally believed to be merely the reflection of forked lightning from a dis- tance. Band lightning, a broad ribbon- like stroke, is caused by a rapid succes- sion of discharges along a path that has been slightly displaced by the wind. Ball or globular lightning is very rare, if it occurs at all. Bead lightning, which is descrihed a a chain of luminous balls, is another type of lightning regarding the existence o! which authorities are not agreed. There } is also St. Elmo’s fire, a globular light observed infrequently on masts of ships. | In addition to all these there are in| duced charges—local electrical disturb, ances between metallic bodies, accom: | panying the discharge of lightning near by. These frequently cause fires if im- flammable material is near, but are not generally dangerous so far as humai beings or animals are concerned. _ The vast majority of victims of light- ning are not killed instantly. They are merely stunned and can be revived by the application of artificial respiratio” and the other first-aid measures com monly employed in cases of drowning or asphyxiation. ‘ Like many other manifestations the mighty power of Nature, lightning 4 coming gradually under the control . science and when the public generally understands the nature of lightning 2” the means of avoiding its dangers, yo hazard to human life and property become virtually extinct. ee ~

Page 123

——__ Plant ightning le of 9 ers who injured nite Was thers at shocked, e of the * shelter nN blind. ’ by a he was S in his ry light- iM until en tom 1at of a! lg under several | mscious, | Ss badly | 1S abso- | and the | bits of | <inds of es differ are not different human g is the lar path be due ‘les and jagged sistance, iminates torm, is ely the) m a dis- ribbon- - succes- that has e wind. | ry rare, | rihed as her type fence of! There ar light | of ships. | are in-| disturb | accom: | ng neat s if im-| are not humai

) hi of light: | hey are ived by piration eS coll rowning | @ jons of tning is| ntrol of | enerally ing and yers, its rty wil!

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