Popular Science Monthly 1924-09: Vol 105 Iss 3

The text was read from the page scans by machine (OCR), so it has mistakes and its columns may run together. See the pages · About this title · At the Internet Archive

Page 1

SEPTEMBER, 1924; Vol. 105, No. 3 25 cents a Copy; $2.50 a Year Popular Science Monthl Most Wonderfully Illustrated Magazine in the World Published in New York City at 250 Fourth Avenue y Coming Next Month How to light your home scientifically. Did you know that color, like music, has the power to stimulate or depress you, to make you gay or sad, to disturb or refresh you? In an extraordinary article in next month’s Poputar ScieEncE Monruty, a lighting expert reveals astonishing facts about light and color and their important effects on your health, comfort, and happiness. Are there twins in your family, or among your acquaintances? If so, you will be interested in an article by Dr. H. H. Newman, Professor of Zoology and Embryology at the University of Chicago. From scientific research, he explains in plain words the mysteries of multiple birth that have puzzled and fascinated men and women for centuries. One of the most enlightening discussions of the subject ever published. This is the day of the mechanical housemaid. What the efficiency engineer is doing for the factory, you can do for your new home while it is under construction by building in the mechanical conveniences that mean a permanent saving of time, labor, and drudgery. In next month’s issue an expert will tell how to do it. What are minerals? Perhaps you think of them only as ores and precious metals. But did you know that minerals probably are the most important things in the world to you—that they go into the food you eat, the very bones of your body, the buildings you live and work in—in fact, that they make possible all the wonders of modern industry and transportation. The scientific facts that Raymond J. Brown tells about them in another of his fascinating articles next month will truly amaze you. The last word in radio is contained in POPULAR SCIENCE MONTHLY’S enlarged Radio Section, the best and most useful of its kind published in any magazine. Here, every month, you will find the important news of radio progress in all its phases, practical construction articles, and useful hints for everybody—all in simple, non-technical English. Thomas Wilfred, musi- cian and inventor, at the keyboard of the organ with which he plays pleasing sym- phonies of light on a screen, just as a musi- cian would play music. The instrument blends color in infinite con- binations and effects POPULAR SCIENCE MONTHLY Issued monthly. Single copy, 25 cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foreign countries, $3. E ntered as second-class matter Dec. 28, 1918. at the Post Office at New York under the act hg — arch 3, 1879. Entered ag second-class maite- at the Post Office Department, Canada. Printed in U. Copyright, 1924, by the Popular Science Publishing Co., Inc. The ‘vote S 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 under- write 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. M3. Fisher, Presid-ni; R. C. Wilson, Vice-President; O. B. Capen, Secretary and Treasurer In This Issue Mira Ceti—an Exploding Star...... By Scriven Bolton, F.R.A.S. The Sky Sports of Tomorrow....... By Lieut.-Comm. FitzhughGreen, U.S.N. The Science of Modern Paint....... By Edward Mott Woolley “Do It Right it It Takes a Year”’. By George Appel The World’s Greatest Power Dam. By Newton Burke How Chlorine Cured My Cold. By Robert E. Martin Wonders of the Deep Sea....... By Raymord J. Brown Model Moon Rocket Explained By Prof. Robert H. Goddard Mechanical Tricks of the Carnival. As told to Walter B. Gibson A Five-Room Home in Three Rooms By A. May Holaday A Martyr in the Cause of Science. How Chemistry Is Feeding Us... By Ellwood Hendrick, Sc.D. Practical Science in the Making.... Money Cleansed by Washing Machine Garden Table Folds Like Umbrella.. . Stereopticon Uses Rolls of Film. .... Locomotive Has Diesel Engine... . Automatic Teller Takes Deposits. . A Back- Yard Gas Plant............ Pigeons Whistle Concerts... .. Bird Is Model for Helicopter. . . me ‘Two Gient Lobsters: ... ... 2. 6.0.5.0 A Miniature Fire Engine........... Smallest New York Store.......... Three-Wheel Fire Truck........... Cutting Steel Under Water......... Stethophone “‘Broadcasts”’ Heartbeats Subway Coin Machine............. Model of Hudson Tunnel........... Pocket Catch Safeguards Watch..... Ornamental Garden Telescope...... The World’s Most Powerful Magnet.. Wire Reinforcement for Brick Walls.. Turntable for Railway Motor Cars... World's Largest Belt............... Automatic Door Check............ Road-Finishing Machine........... A Thirteen-Month Calendar........ Applied Science in the Household.... Swinging Pendulum for Crossings. .. Motorcycle Has Twin Engines...... Service Station Deposit Boxes...... Laboratory Tests for Used Cars..... Novel Automobile on Stilts......... Combined Tractor and Grader...... Airplanes Aim at Speed Records..... Wind —? in Aviation School yee Pnotoneuaks at ate Deiat. rm (GS chats Trench Forms Natural Silo........ Truck Drives Through Smokestack. Roadside Barbecue for Motorists.... Loe en A. | tS | ae irs Folding Dining-Room............ Ornamental Lamp of Cord........ Cutting a Huge Steel Shaft Washer for Tennis Balls......... : How Much Science Do You Know?.. Gravity Level in Three Sections. . . Kaow VOUT ical... sic s ees ; An Elevator Scaffold........... The Progress of Radio... od By Jack Binns Back Stage with ‘‘Radio Mike”’ By W.T. Meenam How to Build a Super-Heterodyne Set By Joseph Calcaterra Radio Hints for Everybody. Riding the Storm.......... Where Is the Automobile Going? By Leslie V. Spencer, M.E. New Automobile Accessories. . Keeping Your Car in Good Order The Home Workshop..... .77 Better Shop Methods..... .82 And other timely articles and pictures

Page 2

Page 3

1 |! \ baie ——' ——— AKE this situation. A man ce had worked all his life in a routine job at low pay sud- denly surprises his friends by moving into a better neighborhood, taking a big house, buying a car and blossoming out as a well-to-do and influential citizen in his new com- NOW Fi The Book That Has Shown Thousands the Way to Amazing Salary Increases POPULAR SCIENCE MONTHLY And in this book they found a comparatively easy way to go from low pay to better earnings. Simple as A B C Sounds remarkable, doesn’t it? Yet there is nothing re- markable about it. There are certain ways to approach munity. How did he do it? What is the secret that he used? Simple enough. He knew that the biggest money in business is in selling, and though he felt that he couldn’t sell a thing he learned the secrets that make Master Sales- men, and then be- gan to make big money. If only one man had found inspira- tion enough in this remarkable book to make a brilliant suc- cess in the Selling feld—in a job pay- month, READ! : Charles Berry, of Winterset, Ia., stepped from $18 a week as a clerk to a position mak- ing him $1,000 the very first J. P. Overstreet, of Denison, Tex., read this book, left a job on the Capitol Po- lice Force, and in six weeks earned $1,800. Portland, Ore., an ex-service man, earned $554.37 in one week, George W. Kearns, of Oklahoma City, found in this book a way to jump his earn- ings from $60 a month to $524.00 in two weeks, and C. W. Campbell learned from it how he could quit a clerking job on the railroad to earn $1,632 in thirty days. different types of prospects to get their undivided at- tention — certain ways to stimulate keen interest—cer- tain ways to over- come objections, bat- ter down prejudices, outwit competition and make the pros- pect act. If you will learn these _princi- ples, there is await- ing you a brilliant F. Wynn, success and more money than you ever thought of earning. This book ‘‘Modern Salesman- ing him many times his former salary— then you might call it luck. But thousands have done it. Your One Chance to Make the Biggest Money of Your Life Not one of the men whose names appear above had ever sold a thing before—not a dime’s worth. If you had told one of them that he could sell he would have laughed at you. They were frankly skeptical. Yet every one of these men, through reading this book, discovered the fallacy of this vicious old idea that Salesmen are “born.” They learned that Master Salesmen are made! ship,” tells exactly how the National Salesmen’s Training Association will make you a Master Salesman. As soon as you are qualified and ready, the Employment Service of the National Salesmen’s Training Association will help you to select and secure a selling position as city or traveling salesman. Now Free to Every Man Who Will Act at Once We are not making any extrava- gant claims about what we will do for you. We don’t have to. The records of the real successes for which we are responsible are so overwhelmingly a testimonial of the fact that any man of average in- telligence can become a Master Salesman that we are willing to leave the decision entirely up to you. All of this proof and many important features about Salesman- ship are contained in ‘‘Modern Salesmanship.”’ It is yours—FREE. Send the coupon for it today. It will show you how you can quickly become a Master Salesman—a big money maker. It will tell you about the National Salesmen’s Training Association system of Salesmanship Training that has meant prosperity to so many thousands of men— about the National Demonstration Method that gives you actual ex- perience while studying—and all about the fine opportunities that await you in the selling field. Failure to act may mean that you lose the one big chance of your life to leave forever behind you the low pay of a routine job. National Salesmen’s Training Association Dept. 15-M 53 W. Jackson Boulevard Chicago, IIl. TRAINING “yy, Strat ~ MATIONAL SALESMENS TRAINING ASSOCIATION oe mae a RD ; National Salesmen’s Training Association , I Dept. 15-M, . I I 53 W. Jackson Boulevard, Chicago, IIl. yy simply want to see the facts. Send me I] I FREE your Book, “Modern Salesman- | I ship’ and Proof that I can become a | | Master Salesman. | In NAMIC: 6.002 cas cece cence oe KHOR Rnes I 1 I Address........0. does. ereioeewaramalaiecetersrs i l j City. ..sseeeeeeeeee a:eieserai Saale ocala IL Age...... Occupation...cccccccceeesess 1 Age... p “3

Page 4

POPULAR I am teaching trades to men who want to get out of white collars and into overalls. Who want to quit being wage slaves, whose job a strike or bad busi- ness or employer’s whim can terminate without warning. Who want a chance to be independent, make real money and own their own business. I refer you to sixty thousand men who found the way to success by send- ing for my catalog. Earn $50 a Week and Up! If you are looking for work at $50 a week and up, if you would like to get into some- thing sure and solid that will give you suc- cess and independence, and can put in a few weeks this winter in TRAINING, write me today. With over TWELVE MILLION automobiles run- ning the demand for mechanics, demonstrators, chauffeurs, truck drivers, garage men, etc., is greater than ever before. Countless opportunities in cities and towns and even remote places. I esti- mate there are 20,000 Sweeney trained men owning their own garage or business. FREE $c‘ Special Offer Get my FREE 64-page catalog. It shows hundreds of actual photographs of men at work in my mag- nificent new school. Tells all about wages, profits, opportunities in auto and tractor business. Ex- plains step by step how to learn. Interesting letters from graduates telling how they made good. Shows how men come from all over the world to this big school. Makes you want to join the crowd. Tells everything you want to know. I will gladly send you a copy, beauti- fully illustrated. Vl 7 tell you how to get into Sen d Th iS business for yourself. N ow = No colored students ac- cepted. E. J. SWEENEY, President LEARN A TRADE AUTOMOTIVE & ELECTRICAL 10 J SWEENEY BLDG KANSAS CITY, MO. SCIENCE MONTHLY WEENEY - System of Practical Instruction is the ONLY way to learn if you want to save time and money and be properly trained. You get this at the famous trade school, the MILLION DOLLAR SWEE- NEY SCHOOL and you get it nowhere else. I have helped 60,000 men to success. The way to learn is easy. You don’t need any experience, age makes no difference. I teach with tools, not books. You learn by ac- tually doing the work. I am making a Special Thirty Day Offer. That is why you should not delay. The first step is to send for my big Free Catalog. ee ee eee eS SSeS Se ee aS a ee eS eS eee EMORY J. SWEENEY, President Dept. 10-3, Sweeney Building, Kansas City, Mo. page catalog and Special Offer. \ Send me free, without any obligation on my part, your 64- ~~ ay et OF ne ee ue eee oe Sees Oe

Page 5

r 64-

POPULAR SCIENCE MONTHLY Let Me | It Bring You *9000 a Year aN) ane ee |

off \ How to

You men who are slaving away in small-pay jobs, hoping this cherished goal was to write to me for the same free proof and striving for better things, I wish you could be with me I want to send to you. They followed my advice and today here for just a few moments. I would show you how thousands are leading happy, prosperous lives—many drive their own of men just like yourself have quickly stepped into high-sal- cars, own their own homes and have plenty of money to aried positions and brilliant success in this fascinating field spend for the other good things of life. They are Electrical Ex- of electricity. In each and every case their first step toward perts—‘‘Cooke-Trained’’—earning $3500 to $10,000 a year! Be an Electrical Expert Learn at Home Get into this great field of Electricity! Know the magic force, the ways and means it is harnessed for use in indus- try, and a thousand jobs will be opened to you at salaries far beyond your fondest dreams. Read Pence’s story at the right! Let it be your guide post to success! Hundreds of other Cooke-Trained men have done as well, and many better! And how? Simply by taking this specialized train- ing that quickly fits any man, no matter what his age or pre- vious education, to take his place with the big-pay men of the country. You needn’t give up your present job or go away to school; by this amazing method you may learn right at home in your spare time. $3500 to $10,000 a Year Twenty years of actual work all over the world in the electrical field gave me a grasp of just what a man must learn to fill an important position. My experience taught me that a man must know first the principles involved and then the best methods to apply and regulate those principles. Why make a man wade through a lot of useless study, wast- ing months of precious time. And so, at enormous expense and years of effort I evolved a system of training that is stripped of every useless step. I will make the student a practical worker! I will place in his head and hands the means to make big money as a skilled Electrical Expert! I will fit him in a short time to earn a princely salary, $3500 to $10,000 a year, for his skill! Thousands of Happy Men Say “There Is No Other Training Like This” . You have given me a most wonderful training, a train- ing no other school can, I feel sure, approach, much less duplicate,” says F. E. Radcliffe, one of my boys who is making good in Ohio. I wish you could see the thousands of letters I get like this! John Burke of Baltimore made $750 in spare time before he finished his training! Think what this means to you! No frittering away time serving a costly apprenticeship! Every step in this fascinating training adds earning power. You quickly become a prac- ucal man, ready to fill a bigepay job. Many of my boys set up in the Electrical Contracting usiness, wiring houses, repairing motors, generators, elec- trical appliances, installing farm lighting systems, etc. Others set up shops and spaces in garages for repairing - a il systems on automobiles, trucks, motorcycles, etc. ‘hey re fitted at once to start in business for themselves, With practically no investment. And with the big plants, fven the ordinary electrician makes big money. But the Trained Expert is the man who is Boss—he is the big-pay

man. With the training behind you, you can claim such an enviable place for yourself, Cooke Trained Man is the "Big Pay "Man

You Cannot Lose—I Guarantee [, » Your Complete Satisfaction You don’t have to take my word for one thing. So sure am I that after taking this training you can step right intoa high-salaried position, and you will thrill with the newly found power that is yours, that I guarantee under bond to return every cent of tuition you pay me, if you are not abso- lutely satisfied that it is the best investment you ever made. Electricity needs you—it offers you boundless opportunity for a brilliant career. I have tried to remove every stum- bling block toward accomplishing your ambition. I will help you win, if you will let mel FREE—If You Act Now—FREE Big Electrical Outfit I know that it is only by practice with actual instruments and materials that a man can become a practical electrical 9000 A AR expert. For that reason I give you without charge or stipu-

lation a Complete Outfit of Electrical Tools, Materials, and The picture above shows Mr, Measuring Instruments. I also furnish you with supplies, W. E. Pence of Albany, Oregon, examination paper and many other things that other schools in his working togs. Pence is a don’t furnish. You actually start early in the course to work ‘‘Cooke-Trained”” man, and_ his letter below shows what he thinks at your profession, rapidly becoming proficient, ready to do of my course. any electrical job. EXTRA—A Course in RADIO err, Given FREE for a Short Time cr ye gg Moe yon just gotten out regarding my The up-to-date Electrical Expert must know radio or new shop. Business is going wireless work, how to make and repair the various equip- strong, paying me now some- ment. This is a mighty profitable field today, and many men thing over $750 a month above are making big money init. Because I want to make this my ae eo go ae ee banner vear, I am now giving this $45.00 Course in Radio for my success, because it was absolutely Free to new students. Don't miss this remarkable your wonderful course and method offer which might be withdrawn at any time. of instruction that put me where Make up your mind now to get into this great profession I am. , cma quick. Every day lost keeps you away that much longer Your true friend, from prosperity and happiness! Mail the MAIL W. E. PENCE. coupon today for my big free book, ‘‘How to Become an Electrical Expert,’”’ and COUPON other free proof that I can put you into TO-DAY the class with Pence and thousands of other Cooke-Trained men who are making sees cme meme meme commas SE SD sD SS SD princely incomes. j L. L. COOKE, Chief Engineer si Chicago Engineering Works, Dept. 36 L.. L. COOKE, 2150 Lawrence Ave., Chicago, III. Chief Engineer, Send me at once ‘‘How to Become an Electrical Expert” with other proof that I can become a big-pay Electrical Expert through your_Training. Register me for your CHICAGO ENGINEERING WORKS, Dept. 36, 2150 Lawrence Ave., CHICAGO, ILL.

Special Free Offers. You send this FREE without any obligation on my part. DE ee ee NE ree ee . City co cwaanasedesuenanen esaceeneu EtCscacc<<<< OccuUPatloR. coceccceccescevesssesssesss Age...----- ees ee ee ee eee Z

Page 6

POPULAR SCIENCE MONTHLY

Making Opportunities

; SS: | Gee ; eS é ij- © <<] ae ( am | AUTOMOBILES AND ACCESSORIES

PATENTS—Wiite for our Guide books and ‘Record of Invention Blank" before disclosing inventions. Send model or sketch o1 your invention for our free Examina- tion and Instructions. Terms reasonable. See ad- vertisement on page «a Victor J. Evans & Co., 189 Ninth, Washington, D. AUTOMOBILE oe Weed parts for most any car at half factory list prices. Allen, Briscoe, Buicx, Cadillac, Chalmers, Chevrolet, Dodge, Dort, Grant, Hudson, Hup- mobile, Oakland, Overland, Oldsmobile, Reo,Studebaker and many others. Send list of parts wanted. Century Auto Parts Co., 4105 Olive Street, St. Louis, Missouri. $1.25 BUYS a posilive a —y light Tell-tale. Handy Specialty Co., Somerville, SPORT Speedster and racing boauies for Fords; build to order. Build your own Bucket Seat speedster. Send $1.00 for blue prints, instructions, and life size paper patterns, complete; Keller Auto Boc y Co., Inc., Dept. 24, 317 W. Winkler Ave., Louisville, Ky. MONEY!—Silvering autolights, radiators, ae Refinishing tableware, stoves, brass beds, ete. Out Methods free. W rite—Sprinkle-Pl: iter, Dept. 96, Seaton” Indiana.

BUY a Gas Gun for $2.50 and avoid stopping on the road because out of gas. Handy Specialty Co., Somer- ville, Mass. PROTECT your springs with positive (inexpensive) spring leaf Lubricators. Automatic Spring Oiler Co., Drawer 18, Corona, N. Y. FORD ACCESSORIES SPEEDSTER fans—see **Red-i-Kut” ad. page 130. MOTORCYCLES, BICYCLES, SUPPLIES OVERSTOCKED—200 Useu Motorcyeles. Rold at once. We have Harley-Davidsons., Hlendersons, Excelsiors, Clevelands. Write for our Bargain List. Myerow Brothers, Dept. ¢ 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.

Must be Indians, Prices $25.00 Up.

USED parts for all motorcycles cheap. Schuck Cycle 0., 1922 Westlake, Seattle, Wash.

AVIATION THE American School of Aviation announces a new correspondence course in mechanics of aviation. A thorough training in practical aeronautics. American

School of Aviation, Dept. 674-B, 3601 Michigan Ave., Chicago, Illinois. BOYS get a three foot model aeropline free. Nothing tosell. Write to Aero Shop, 3050 Hurlbut Ave., Detroit, Michigan.

MOTORS—BOATS—LAUNCHES BOATS that always Go are propelled by k ord engines. Ford boat dope sent free. Harry Rider, 206C Commercial Bldg., Norwalk, Conn.

MOTORS, ENGINES AND MACHINERY MOTORS— Manufacturer's Surplus Sale. KHP, $8.50;

HP, $32.50; 1 HP, $54.50. 8 Volt Charging Generators, $8.50. Complete Lighting Plants—Generators—Light Machinery. Write for Catalog. Motor Specialties Co., Crafton, Penna. CONCRETE Catalogue free. Third St., St.

Building Block Machines and Molds, Concrete Manufacturing Co. 307 So. Louis, Mo.

MCD=ILS AND MODEL SUPPLIES HULIT & Co., 625 Jackson, Chicago, Ills. Experi- mental Machinists. Model Makers. Dies. Patterns, Complete general Machine shop. Ex-Lamson.

WE make working models for inventors and experi- mental work, and carry 2 complete stock of brass gears and model supplies. Send for catalogue. The Pierce Model Works, Tinley Park, Illinois.

MANUFACTURING DIES, Tools and Gener.l Manufacturing. Models and manufacturing of new inventions our specialty. Logan Machine Co., 126 S. Clinton St., Chicago, Ill. DEVELOPING ideas and manufacturing our spe- cialty. Absolute satisfaction. 33 years’ a e; write us. The K. & B. Die & Specialty Co., 2018 Elm St., Cincinnati, Ohio, Dept. C. FOR THD HOME GRANDFATHER clock works $5.00. Build your own ease, 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 limps, lanterns and heaters. Catalog free. Little Wonder Mig. Co., Terre Haute, Indiana. BEAUTIFUL chila’s china ¢ .binet, tions 25c. Circular Free 2651 Sth Avenue, New York. PURCHASE a beuutiful Electric home at Jobber’s pvice. Walter L. Ravenswood Ave., Chicago.

pitterns, instruc- Brogrens Kiddy Kabinets,

Fountain for your Haanel & Co., 4521

SAVE 1-5 to 1-2 the money you spent for coil last and get more heat by attaching the CROWN Fuel Sav to the feed door of your furnace. This inexpensive device is an amazing heat-producer and coal-saver. Works automatically—never gets out of order. Guaranteed to save 20% of coal or money refunded. Write CFSCO. 14 N, 10th St., Richmond, Ind.

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 fascinating 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. oeeeee - $10.00 Second Prize ...... 5.00 Third Prize ...2.-e.- 3.00 And 7 Prizes OrSigeesch ..<«cse 188 First read every one of the ““Money Mak- int Opportunity” advertisements on pages six to twenty. Check the ones that in- terest you. Then read over the ones you have checked and decide on the one that interests you most. Then 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 Sept. 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 Novem- ber issue. Address your prize letter to Contest Editor POPULAR SCIENCE MONTHLY 250 Fourth Ave., New York City

Last Month’s Prize Winners The First Prize of $10.00 goes to George Dawson, Montreal, Canada, for his letter on the advertisement of ‘‘The Union Loom Works.”” Here is Mr. Dawson’s letter: Dear Sir:— ‘“‘Money Making Opportunities’’ as per ads in Popular Science, touches the spot every time. I soon found my ‘‘money making opportunity”"’ through the offer of ‘‘The Jnion Loom Works” ad, a sure and profitable business getter at all seasons. I have at present more orders than I can fill at prac- tically my own price, and there appears to be no limit. GEORGE DAWSON Mr. S. F. Howard, Jr., Iuka, Miss., wins the Second Prize for the following letter re- garding the advertisement of the R. J. Carnes Company. Here is Mr. Howard’s letter: Dear Sir:— While looking Science Monthly for a ‘‘money making opportunity”’ to take up in my spare time, the advertise- ment of R. J. Carnes, Tallapoosa, Georgia, struck me as being exactly what I wanted. It is a real money-making offer, such as I can always find in Popular Science Monthly: not a fake ‘‘get rich quick’’ scheme, but a fair, straightforward, open opportunity for any person who is looking for such. S. F. HOWARD, JR. The Third Prize goes to C. M. Reynolds, Spruce Creek, Pa. over Popular The winners of the other seven prizes are:— S. E. Miller, Corry, Pa., Mrs. Bertha Brooks, Long Prarie, Minn., James E. Noble, Tor- onto, Canada, Estes Hawkes, Drummond, Idaho, Julian B. Tuthill, Sayville, N. George D. Reynolds, Altoona, Pa., James Monticue, Canton, Ohio. hd and

Rate 25 Cents a Word. Advertisements in. tended for the November issue on be received by September 5th RADIO AND SUPPLIES RADIv ‘Tuves repaired and excaanged; write for free circular, “How J 4 Away with Storage Batteries on Tubes.” C, . Radio Tube Works, Essex Court, Newark, N. J. RADIO Gencrators: 500v 100 watt, $28.50. Battery Charging Generators, $8.50. High Speed Motors. Motor — Sets all sizes. Motor~ Specialties Co., Crafton, mna. 2,650 MILES Distance with one tube. Any Novice understands our Simplified Instructions, including Pane} my a 25c. Vesco Radio Co., Box PS 117, O21 ali RADIO a aii, Diz, bg UV200, UV2014, $4.25. Dutch radio tubes, ’D12, D200, D201A, $2.50, Crystal set, 50c. Add postage. ' Radio Sales Co., 1168 North Kingshighway, St. Louis, Mo. WHY Not Rech Out witn your crystal set? There's music on your aerial every night — stations far away! I have shown thousands of people how to heir long dis. tance programs without tubes. Write me today. Leon Lambert, 670 Sout Volutsia, Wichitr, Kansas. EDUCATIONAL AND INSTRUCTION DOUBLE ent. z boo«xKeeping mastered in 60 hours: guaranteed; diploma, a pg ag al Bookkeeping In- stitute, Springfield, Missouri, Desk 10. LINCOLN-JEFFERSUN University. Home Study in Academy College, Theolozical, Law, Music, Pharmacy, Business and Graduate schools, leading to degre es. Box G, Capitol Building. Chicago. USED correspon‘ience courses bouzuat 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 taugnt by = muil. Courses in Arithmetic, Algebra, Geometry, Mensura- tion, Trigonometry, Logarithms, Mechanics, ‘Mechanieal Drafting, and Tool Designing. Harding ‘School, Box H. Highland Park, Mich. ALL men, women, boys, girls, 17 to 65, willing to accept Government Positions, S117-S2 50, 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. FIREMEN, Brakemen, Baggagemen, Sleeping car, train porters (colored). $140-$200. Experience un- necessary. 838 Railway Bureau, East St. Louis, Ill.

Dukes,

WRITE photoplays; $50 each. Experience un- necessary; details free to beginners. Producers’ League, 312, St. Louis. RAILWAY Mail, Postoffice Clerks, Carriers, Customs, and many other positions open,—$1400-$2300 yearly. Write today for 36 page booklet showing how to obtain one of these desirable life positions. Chicago Civil Service College, T-70 Kesner Building, Chicago. ae a detective. Excellent opportunity to earn big ney, travel, thousands of dollars offered in rewards. Established 1909. Particulars free. hg to C, T. Lud- wig, 424 Westover Bldg., Kansas City, MEN—Experience unnecessary; ae investigations; reports; salaries; expenses. Write Ameti- can Foreign Detective Agency, 321, St. Louis, Mo. RAILWAY Postal Clerks—Start $133 month. Rail- Toad pass; expenses paid; questions tree. Columbus Institute, N-2, Columbus, Ohio. DETECTIVES Earn Big Money. Excellent oppor- tunity. Travel. Fascinating work. Experience un- necessary. Write, George Wagner, former Government Detective, 1968P Broadway, N. Y. TRADE AND TECHNICAL SCHOOLS EARN $10 to $20 per day. Learn sign painting, Auto painting, decorating, paperhanging. Be an expert in a few weeks—Low cost—Actual work—No books—Catalog Free. Chicago Painting School, 157 West Austin Avenue, Chicago. CHICAGO Technical College offers short, intensely practical courses in Drafting and Enginecring—civil, mechanical, electrical, structural—Architecture, Building Cc onstruction, Plan R Reading, etc. Courses fitted to your needs. No time wasted. Instructors are experts. Grad- uates in demand at big salaries. Opportunities for part- time work while studying. Day and evening classes. 2ist year. Enter any time. No special preliminary training required. Low tuition—easy terms. Write fot )2-page illustrated Blue Book, describing opportunities open to our graduates. Cxricago Technical College, 23 Chicago Tech. Building, Chicaro. BE a Bricklayer. Attend a sc2ool operated by Building Contractors. Three Months Da y Course $75.00. Associ

make secret

ated Building Employers, 128 A. B. E. Building, Grand Ranids, Mich. WANTID WANTED: Light Macuinery, Lithes, Drill Presses, Model High Speed Gasoline and Steam Motors. Best Cash Prices Paid. Motor Specialties Co., Craiton., "Penna. DETECTIVES needed everywhere. Experience ul- necessary. Particulars free. Write, George Wagner, former Government Detective, 1968P Brovdwey, N. WANTED—Representatives in every f ctor yin = Jnited States. Popular Science Monthly, 225 West 39th Street, New York. 4 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. Casting forms made to ore. Catalog, advice and information free. Metal Cas Products Co., 1696 Boston Road, New York. More Money Making Opportunities on pages 8 to 20

Page 7

There's T away! ong dis. if ae mann, ‘ eee ) hours; ving In- study in armacy, S. Box Y mul, [ensura- chanical ol, Box 0 accept Sstation- diately, towns. tem, 188 ing car, nce un- Il. ice un- League, Sustoms, . yearly. oO obtain z0 Civil earn big rewards. , T. Lud- ce secret e Amerti- fo. \. Rail- olumbus t oppor- nce ule ernment Ss ——— ng, Auto ert in a —Catalog Avenue, intensely ig—civil, Building | to your 3. Grad- for part- r classes. ‘liminary Write for ytunities lege, 23 ae, Building _ Associ- x, Grand — a ence ule —————— TIES —— tal Toys ities - Spy ci 4 b> Making Successful Men. by Home-Study Training How can I make more money? How can I advance more rapidly in Literally millions of untrained men—yourself, perhaps, among them—are continually disturbed by those two questions. ‘Be industrious; keep everlastingly at it’? —that’s the way the writers of copy-book maxims would tell you to go about it. But honestly—are you fooled by that sort of talk? Why, you yourself know dozens of fellows who work just as hard as beavers, yet draw barely enough to business ? keep them alive! Argue it any way you like, it takes something beside mere work to push men ahead—it takes sfecialized work. And to suggest, for a second, that an untrained man—no matter how hard he works—is going to be promoted to a highly specialized position—such as that of Auditor, or Traffic Manager, or Sales Executive, or Expert Correspondent, or Production Manager, or Legal Counsellor—without first eguipping himself for that position, is as absurd as to intimate that the boatman in the park who has been on the job for twenty years is likely to be chosen captain of a trans-Atlantic liner! % % * Recognizing these facts—and surely no one can dispute them —what is the wise thing to do to change one’s situation for the better? _ Many a happy-go-lucky chap will tell you that all you need do is to keep your eyes open and promotion will take care of itself. It will. But, oh, how slowly! While one man is advancing by this tedious route from $25- a-week to $30-a-week to $35-a-week, another chap, not a bit smarter than he, is climbing from $15-a-week to €30-a-week to $50-a-week to $100-a-week. If you doubt it, look about you! Talk with the men still in their twenties and early thirties who are swinging $5,000 jobs! POPULAR SCIENCE MONTHLY MSS WR / | \\ ANY (\ A —— \ as P = \\ Y r No—there’s more to advancement than merely ‘‘catching onto things.’’ TIME is the all-important factor—and that is the big reason why thousands of earnest men have refused to wait, but have turned instead to LaSalle Extension University and have shortened by many ycars their journey to success, That they —in so doing — have acted to their own advantage is borne out by the fact that during only three months’ time as many as 1193 members reported definite advancement which they were frank to attribute to home-study training under the LaSalle Problem Method. The total salary-increases so reported amounted to $1,248,526, az average increase per man of eighly- nine per cent. Your future is, of course, your own problem—and no one can solve it but yourself. If you are content to drift, you will find plenty of company though little profit. If, on the other hand, you are really in earnest when you say that you want to get ahead in business, you will find both companionship and gain in home-study training under the LaSalle Problem Method. Below this text there’s a coupon—very similar to the one which has set many, many thousands on the path to success. A good way to gauge your strength of purpose is—by what you do with that coupon—NOW. LASALLE EXTENSION UNIVERSITY The Largest Business Training Institution in the World — .—— =e ae eee eee oe ee eee oe oe oe oe OO eee eee eee ee eee eee ee ee ee ee ee eee ee oe ee LASALLE EXTENSION UNIVERSITY Also a copy of your book, “ Business Management: Training for Official, Managerial, Sales and Departmental Executive positions. [Modern Salesmanship: Training for posi- nen as Sales Executive, Salesman, Sales ach or Trainer, Sales Promotion Manager, M ‘nufacturer’s Agent, Solicitor, and all posi- tionsin retail, wholesale, or specialty selling, ia []iigher Accountancy: Training for posi- on as Auditor, Comptroller, Certified Expert, Freight Solicitor, etc. Financial Institutions. Public Accountant, Cost Accountant, etc. | Fe nana paramo pene Pedy a — Training for naegen yo Shop anagement, such as that of Superin- ar r = tendent, General Foreman, Foreman, ("aa Bookkeeping: Training for BH P. A. Coaching for Advanced Ac Law: Training for Bar; LL. B. Degree. Cc . [ ]Sommercial Law: Reading, Reference and Consultation Service for Business Men, Sub-Foreman, etc. Neme a Dept.983-R Please send me catalog and full information regarding the course and service I have marked with an X below. Ten Years’ Promotion in One,” all without obligation to me. Traffic Management — Foreign and Industrial Management Efficiency: Domestic: Training for position as Rail- road or Industrial Traffic Manager, Rate Railway Station Management: Train- ing for position of Station Accountant, Cashier and Agent, Division Agent, etc. Banking and Finance: Training for executive positions in Banks and sseueagesacs VSL GT tes) oe ce ea nee Chicago, Illinois Business Eng- Training for positions in \/orks Man- lish: Training agement, Production Control, Industrial for Business Engineering, etc. Correspond- Pcrsonnel and Employment Manage- ents and ment: Training in the position of Per- Copy sonnel Manager, Industrial Relations Writers. ‘ : _ Man: _er, Employment Il!anager, and Commercial Spanish: Training for positions relating to Employee £-.rvice. position cs Foreign Correspondent with Modern Business Correspondence en eee ee cesta and Practice: Training for position as Effective Speaking: Training - - = Sales or Collection Correspondent, Sales art of forceful, effective apese ? ) Promotion Manager, Mail Sales Man- Ministers, Salesmen, Fraternal Leaders, ager, Secretary, etc. Politicians, Clubmen, etc. position as Head Bookkecper. countants, cccccccecoosoosee®

Page 8

$90 Drafting Course FREE 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= 1$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 Iam doing fine. Am earning asalcry of $300 per month, besidcs 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 youforall =. your personal interest and help you Dronictan gavemesofar.”” (Signed) J. B. Dobe (Name and address upon request) Write and I'll tell you how I make youa first- class, big-money-earning draftsman inavery few months! I do this by a method no other man or se = can imitate. give a Guarantee youpersonaltraining at home by mail un- To train you antil | til you are actually you are placed in placed in a position @ position paying aying upto $250and up t> $250 and $300 a month. Six $2300 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. magnificent set of instruments which will build your success in draftsmanship at once for my, great book — “Successful Draftsmanship.” Find out about the simply marvelous opportunities ahead now. What great salaries and possibilities there are] Send the coupon for free book TODAY! Free Course Offer Coupon CHIEF DRAFTSMAN DOBE 1951 Lawrence Ave., Div, 13-66, Chicago Without_any obligation to me please mail — bonk, ‘‘Successful Draftsmanship’’ and full ticulars of your liberal ‘‘Personal a ~% fer to a few students. It is understood I am obli- gated in no way whatever. Name... Age....------ ae a ee ere ne eee er en POPULAR SCIENCE MONTHLY Money Making Opport ties ADVERTISING ADVERTISE in 24 metropolu.. uailles, 24 Wworus, $15.00. Helpful Guide listing 1Uv0 publications, 4c stamps. Wade Company, Baltimore Bldg., Chicago. 28 WORDS in 80 Country Town Newspapers, $3.40. Shaw, 221 A. Northeast, Wsshington, D. C. ADVERTISING rates for magazines and weeklies free. Charles A. Lutz, Apartment 241, York, Penn- sylvania. 24 WORDS combine list of 70 Sunday and weekly newspapers, $6.00. AdMeyer, 4112 P, Hartford,, St Louis. ONE Inch in 136 N. Y. Country Weeklies $15. Only one cut needed. The Messenger, Smithtown Branch, Long Island. ADVecRTISING in all magazines and newspapers at publishers’ lowest rates. Sales letters, booklets, folders, planned, written, illustrated. Taylor's Advertising Ser- vice, Dept. A, Freeport, Tinois. 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 ou 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. PRINTING, ENGRAVING, MULTIGRAPHING ENVELOPES or Saipping Tags at sensible prices. R. D. Elliott, 305 South Third, St. Louis. COMMERCIAL | Printing. Write requirements. Franklin Press, B-34, Milford, New Hampshire. 500 TWO Color Letterheads, $2.75. Samples free. Superior, 1825 Roosevelt, Indianapolis. BETTER Printing for Less Money. Write us about your printing needs, and you will sive money. Ernest Fantus Compiny, 525 South Dearborn Street, Chicago. EMBOSStD business, personel stationery. Samples, stamp. Daniels P. Company, Pittston, Pennsylvania. YOUR nme and address printed on 100 fine cards for 50c, prepaid. Greenfield Printing Co., 191 Osborn St., Brooklyn, es 100 EACH, Letterhe: = and Envelopes, $1.00. Cul- pepper Press, Box S5, F: Ark. TRADE-MARKS, aa ud designs, illustrations for advertising. Letters, folders, booklets’ written. Quick service, fair prices. Taylor's "Advertising Service, Dept. B, Freeport, Illinois. SIMPLE Photo-Engraving Process. Line and Half- tone Cuts. Particulars 2 cents. Horton and Fisher, Princeton, Til. GUMMED LABELS NAME and address, 500, 0c. Others rolls or loose. Stationery, 200 sheets and 100 envelopes printed $1.00. Eastern Label Co., B, Clintonville, Conn. DUPLICATING DEVICES STENCIL Duplicating Outfit—$2.00, $3.00, $4.00. Prints Typewriting, Handwriting, etc. On Approval. Primos Specialty Co., 3-X, Primos, Pa “MODERN” Duplicators, save Time, Labor, and Money. Gets business. Reproduces Typewritten or Penned Letters, Drawings, Lessons, Music, Menus, Bids, Notices, Specifications, Maps or anything in one or more colors. Prints two per minute. Special sale on. 30 days’ free trial, $2.25 up. Booklet free. J. V. Durkin-Reeves Co., Pittsburgh, Pennsylvania. OFFICE DEVICES ADDRESSING machines, multigraphs, duplicators, folders, check writers, sealers, dictating machines, at about half new cost. Pruitt, 170-Z North Wells, Chicago. ADDING MACHINES FREE tri.l, marvelous free auging machine. Adds, 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. ne Calculator Co., Dept. O, Grand Rapids, Michigan BRANCH OFFICE SERVICE PITTSBURGH Office and Representation Free. Pittsburgh Office Service, 973 Union it Bidg. LETTER SPECIALISTS 20 SUCCESSFUL Collection Letters $1. Win, 403 Gotham Bank Bldg.. New York, N. Y. LET me write your sales letters, oe folders. Wide experience, fair prices, quick service. . Taylor, Box 44P, Freeport, Illinois. MAILING LISTS 12,000 NAMES Indiizna High School Graduates, $3.00 —Hrvey Morley, Angoli, Ind. LABORATORY AND CHEMICAL SERVICE EXPERIMENTE ox: Cc omplete supplies for the chemical laboratory. Catalogue 5c. National Scientific Supply Co., 241 Pennsylvania Avenue, Washington, D.C. YOUR chemical problem solved and working process furnished for five dollars. Write me. . Stedman Richards, Consulting Chemist, Box 2402, Poston, Mass. FORMULAS FORMULAS for useful and salable articles. lour hundred in book form. Fifty cents, postpaid. Pentland Service, 1 Thames Ave.. Norwslk. Conn. INFORMATION COMPLETE, accurate, information on any subject, $1. National Information Bureau, 1429P Milton St., Grand R: ws. Michigan. EGAL questions answered, guaranteed correct, $1.00. E oe Keller, August», Montana INCORPORATIONS DELAWARE Incorporator. Charters; Fees Small; forms. Chas. G. Guyer, 901 Orange St., Wilmington, Delaware. INCORPORATE Delaware. F. Lewis Mettler, 832 Market St., Wilmington. Del. (Fstablished 1909.) 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. Manager, Classified Advertising, Popular Science Monthly, 225 West 39th Street, New York. More Money Making Opportunities on pages 6 to 20 ent HIGH SCHOOL COURSE IN TWO YEARS YOU ARE BADLY if you lack HANDICAPPED (Pe) School raining. 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 TIME ONLY 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 for full particulars and Free Bulletin. American School Bent. H675, ‘ Drexel Ave. and 58th St., Chicado % American School Dept. H675, Drexel Ave. & 58th St., Chicago Send me full information on the subject checked and how you will he!p me win success. ee Architect wees LEQWYCT : ....-Building Contractor __...... Mackine Shop Practice ....Automobile Engineer __...... Photoplay Writer moepul Automobile Repairman -Mechanical Engineer sea Civil Engineer .Shop Superintendent mae Structural Engineer .Employment Manager = Setar tae sceeal Business Manager «....5team Engineer sce Cert. Public Accountant ......Foremanship cexeel Accountant and Auditor ......Sanitary Engineer a. Bookkee per ... Surveyor (& Mapping) aS. Draftsman and Designer _...... Telephone Engineer all Electrical Engineer «.....Telegraph Engineer meee Electric Light & Power _......High School Graduate eoneal General Education ......Fire Insurance Expert -....Wocational Guidance _—_..... Wireless Radio sessed Business Law s+eeee Undecided Name pe - ee a

Page 9

Chicago checked -ractice er rineer ndent anager er apping) neer neer aduate =x pert

POPULAR SCIENCE MONTHLY LF TAUG Ve Be A SKILLED Workman and Hold Your Job in Dull Seasons Do you know that even when work seems hardest to get, building contractors are complaining that they can’t get enough skilled carpenters? Almost any man that says he is a carpenter can get a job in the building season, but it depends on what a man KNOWS whether he gets laid off at the first dull week or not. Spare time reading and study of AUDEL’S GUIDES will help make you the kind of skilled workman that is never out of a job. New Ideas -Modern Methods-Short Cuts This course “‘Audel’s Guides for Carpenters and Builders’’ cons over 1500 pages with thoroughly illustrated charts, diagrams, g lations for every job from making the excava- tion to constructing the entire building. You will find these new comprehensive in addition to being both time- ly and practical. amples of efficient construction work with new solutions, plans, systems, methods, ideas, short cuts, time and labor saving suggestions, new ways that cover the entire theory and practice of the subject illustrated by sketches and forms all specific and practical. Audel’s Guides give you the short cut, professional information you want. No need to guess or take chances. Every day you have before you in this set the exact, practical, useful informa- tion that will help you with every job that comes up in your daily work, ists of 4 handy volumes of raphs, pictures with calcu- Guides most complete and There are 3700 actual ex-

Thousands Say Guides Are Carpenter’s Best Friend ‘‘Reasonable rice’’ I find the Guides very satisfactory. The knowledge in them is much great- er than I antici- pated. A very con- venient size and price is so reason- able that every car- penter should pos- sess a set. —Ralph M. Collemer, Low- ell, Mass. “Valuable for Beginners or Old Timers”’ I have looked over ny Audel Guides and find a wealth of informa- tion. Their size makes them very handy to carry right onto the job. have put my books in my tool kit and have them

ie > sa Aubets. CARPENTERS AND BUILDERS Guipe { ha professional like myself who is try- ing to build him- for ready reference. | foreman or super- figure out the next The arrangement | intendent who can jday's work. —G. of subjects and the | aftord to be with- | M. McJohnston, simple way it is]|out this valuable | R. R.1, Hammond, | self a home at the explained make] work. I wish you | Ind. least expense. — the books very val- | unbounded success. Otto F._ Schulze, uable for the begin- | —George H. Wat-]| ‘Save Money” P, O. Box 143, ner. The rules and | son, 136 Munson The Guides hav Westmont, III. formulas are mighty |} St., io Island | ict more by using the Professional m3 Cultee om information given Carpenters’’ d hould be i in your 3s. W. and show in |. Frantz, Box 77 It is the most }|the hands of all | Tyscarawas, Ohio. handy reference | young’ carpenters , work that I ever [as well as a lot of “Good For came in contact | the older heads. If Amateurs’’ with. It is the very had such infor- thing that theJ|mation 20 years The books are they would |surely worth more saved me |than the purchase building mechanic | ago needs every day | have é u for reference. I | many a hard knock | price; especially as wish to state fur-] and also sleepless |they serve as a ther there is not a‘ nights trying to 'guide to the non-

Aupexs CARPENTERS AND . 4 Buiibers Guive j CARPENTERS AND j | BulLDER eT) 3 2 Lins eaten a trapsareeste BUILDERS MATHEMATICS DRAWING _ PLANS SPECIFICATIONS ESTIMATES HOUSE AND stele) 3 FRAMING LAYINGOUT FOUNDATIONS a. €9 ~

Condensed Contents of Audel’s New Guides Guide No. 1—Over 431 pages—1200 illustrations i to know the different kinds -—-How to make a work bench, of w . —How to use the different kinds of wood. —Complete detailed information on nails and screws. — How circular and band saws are handled. —How to use the steel square. —How to sharpen tools. —How to file and set saws. —How to make wood joints. —Complete information regarding joints and joinery. —How to build furniture. Guide No. 2—Over 455 pages—400 illustrations —How to understand carpenter’s —How to proportion beams, arithmetic. — How to use drawing instruments. —How to understand geometry. —How to read plans, —How to understand trigonome- —How to survey. try. —How to draw up specifications. — How to solve mensuration prob- —How to estimate cost. ems. —How to build houses, barns, — How to estimate the strength of garages, bungalows, etc. timbers. Guide No. 3—Over 255 pages—400 illustrations — How to excavate foundations, —How to attach lath to corne™ — How to build foundations. posts. — How to make water-proof. —How to frame temporary and —How to erect post foundations. permanent braces. —How to build forms for con- —Howtoframe girtsand ribbands. crete. — How to set window frames. —How to proportion foundation —How to frame partitions. footings. —How to distinguish various —How to frame houses. types of roofs. —How to set girders and sills. —How to use the settings 12, 13 —How to frame joists. and 17 on the steel square. —How to construct a well hole. —How to lay out mitre cuts. —How to frame a studding. —How to use tangents, and full —How to frame corner posts. detailed information covering —How to lay out and cut braces. sky lights, scaffold and hoisting. Guide No. 4—Over 448 pages—400 illustrations —How to put on wood, fibre and —How to build stairs, metal shingles. —How to lay gravel roofs. —How to lay tin roofs. — How to hang doors. —How to frame windows. —How to put on siding. . —How to put.on exterior trim. —How to do cornice work, —How to make a mitre box. —How to make a mitre shooting board. —How to plumb and level work. —How to use the chalk line. — How to lay out work. —How to use rules and scales. — How to use all of the carpenter's tools, with over 900 illustrations showing specilically how. —How to lath. —How to lay floors. —How to put on interior trim. — How to paint. —How to give first aid to the injured.

PER MONTH-ENTIRE SETS FREE EXAMINATION POCKET SIZE-FLEXIBLE COVERS 1600 PAGES-3700 ILLUSTRATIONS EXAMINATION Not a cent to pay until you see the books. No obligation to pay until you are satisfied. Send coupon “now—today and get this fine, helpful new set for Carpenters = and Builders. After you ,: have looked them over 5 days send only $1, then $1a month until $6 is paid—if you want to keep them.

Page 10

“What would I do if | lost my job?” UPPOSE your employer noti- fied you to-morrow that he didn’t need you any longer? Have you any idea where you could get another position? Don’t have this spectre of unemployment hanging over your head forever. Train yourself to do some one thing so well that your services will be in demand. Employ- ers don’t discharge such men. They promote them! Decide to-day that you are going to get the specialized training you must have if you are ever going to get—and keep—a real job at areal salary. It is easy if you really try. Right at home, in the odds and ends of spare time that now go to waste, you can prepare for the position you want in the work you like best. For the International Correspondence Schools will train you just as they are training thousands of other men —no matter where you live—no matter what your circumstances. At least find out how, by marking and mailing the coupon printed below. There’s no cost or obligation, and it takes only a moment of your time, but it may be the means of changing your whole life. Mail the Coupon To-day For Free Booklet INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7608-D, Scranton, Penna. Without cost or obligation on my part, please tell me bow I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Business Management [} Salesmanship Industrial Management [| Advertising Personnel Organization _} Better Letters Traffic Management []Show Card Lettering O)Business Law [_] Stenography and Typing Banking and Banking Law [_j Business English Accountancy (including C.P.A.) () Civil Service Nicholson Cost Accounting Railway Mail Clerk J Bookkeeping Common School Subjects Private Secretary [}] High School Subjects Spanish 0 French Lj Ulustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering ry Architect Electric Lighting rj Architects’ Blue Prints Mechanical Engineer Contractor and Builder Mechanical Draftsman q Architectural Draftsman Machine Shop Practice r} Concrete Builder Railroad Positions F chemistry Engineer Gas Engine Operating Chemistry 0 ‘Pharmacy Civil Engineer Automobile Work Surveying and Mapping [] Airplane Engines Metallurgy C) Mining [] Agriculture and Poultry Steam Engineering OD Radio © Mathematics Street 3-6°24 NII 25 -sis oeaeecabuanibbasinansesunsbs kes cevalenecssseeonibiecesbaxaaies Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, ‘ Montreal, Canada POPULAR SCIENCE MONTHLY PHOTOGRAPHY AND SUPPLIES HAVE you acamera? 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 Enlargement in handsome folder 40c. Overnight Service, Roanoke Photo Finishing Co., 212 Bell Ave., Roanoke, Virginia. DEVELOP and print your own films. mulas, 60c (no stamps). “L,”’ Owego, N. Y. SPECIAL! Beautiful “Old Master’ Enlargement, 8x10, 11x14 or 14x20, “Sepia or pastel’’ from negative or photo, $1.00 prepaid. Finest equipped plant in America! Film Artists Productions. Box 417, Los Angeles, Cal. CLEAR, bright prints that will never fade; 3c each for vestpoc ket size; brownie No. 2 and No. 2A, 4c each, larger sizes, 5c each. 8x10 enlargement 55c "from any kodak film. We develop any roll film for 10c; film packs 25c, mailed back same day. Satisfaction guaranteed. Leon Lambert, 670-E South Volutsia, Wichite, Kensos. AUTHORS—MANUSCRIPTS WRITE: for newspapers and magazines. Experience unnecessary, details free. 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 Bldg., Cincinnati, Ohio. $$$ FOR ideas. Photoplay 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. Box 191, Manhattan, Kans°s. Complete for- Results guaranteed. Studio Big pay. Press Reporting BOOKS AND PERIODICALS “NATURE'S FINER FORCES” Colortones; Flectromagnetos; Odicauras; Radio; Cold- lights; Inventions; Wonderful Opportunities; Fifty Lessons; Marvelous Cures; Illustrated; 270 pages. $2.00. Deluxe $3.00. Stevens Science Publishers. 242 Powell, San Francisco. PUBLISH a Magazine of your own. how. Very seg — Lutz Printing Co.. York. Po. MUSIC AND MUSICAL INSTRUMENTS POEMS wanted—Sell your song verses for cash. Sub- mit MSS. at once or write New Era Music Company, 117, st. Louis, Missouri. PRODUCE soft sweet music with a carpenter's saw. Instructions compiled by _a stage artist $1.00 Fred Park, evre Billboard, New York City. PHONOGRAPHS, RECORDS, ETC 90,000 STANDARD 75c, 10-in. ; Vibrations; Lights; We will tell you Information free. Double Phonogr: = Records, Plays any machine, aay hile they last, 500— 10)9-—-l6e. Sample order 5 Records—all different, $4.25. Order today. all Reck, Neshville, Tenn. MOTION PICTURE BUSINESS WRITE photoplays; $50 each. sory. Details free to beginners. 312, St. Louis. Icxperience unneces- Producer's League, NOVELTIES ARMADILLO Baskets, Unique novelty; samples par- eel post paid, plain baskets, $2.50; silk trimmed, $3.50 each; satisfaction guaranteed or money back. Address Charles Apelt, Comfort, Texas. OPTICAL GOODS ARTIFICIAL eyes, $3. Booklet free. 508 Barclay, Denver, Colorado. MR. ADVERTISER: Ask to-day for a copy of tue “Quick-Action Advertising Rate Folder.”’ It contains some really important facts which will prove interesting und 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, Popul: uw Science Monthly, 225 West 39th Street, New York. Denver Optic Money Making Opportunities | — EARN!3000 0'9000a Year Enter fast growing radio field, thousands of big pay jobs waiting for you. . Gov't., Steamships, R, R's s., Corporations eagerly seek Radio trained men, Advancement rapid, earn from $3000 to $9000 yearly, Prepare for Big Pay in Spare Tims My reputation as Radio Engineer and instructor insures you com- plete, speedy success, at home in sparetime; earn while you learn, I make you expert in radio design- ing, enn oe operat- wii ing and teach you only practical A.G.MOHAUPT — “inside” dope. You quickly com- plete my course and step out into Big Pay. No ex- perience required RADIO FREE sit? 1000 MILE TUBE SET For a short time I will give tube radio set in handsome cabinet to men who enroll now, absolutely FREE. Send at once for my FREE wonder-book of inside Radio ‘‘dope.’’ A. G. MOHAUPT, Radio Engineer, yd Ass'n OF AMERICA 4513 » Dept./49, CHICAGO Dear Sir: Send me your FREE Radio Book and your limited plan without cost or obligation. oo oe secccnceoen Se I can make a good penman of you at your home during spare time, 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 years—it CAN and WILL do the same for YOU— “My beautifully illustrated 32-page Book “‘How to Become a Good Penman” FREE It contains many beautiful specimens of penmanship show ing what others have accomplished by the Tam- blyn System, with testimonials and gencral information about our course—( Your name elegantly written on a card if you enclose stamp Jor postage). Ladies taught as successfully as men. WRITE TODAY, address F. W. TAMBL 437 Ridge Bidg., Ww. YN Kansas City, Mo., U.S.A. MAGIC TRICKS 375 MAGIC Tricks, 40c. 8214 East 144th, New York. TRICKS, jokes, magical escapes. Illustrated catalog, Dept. 550, Oshkosh, Wis. CHALK TALKS LAUGH producing program, $1.00. Cartoonist Balda, Oshkosh, Wisconsin. MISCELLANEOUS Tin Soldiers, Indians, Murines, Trap- pers, Animals. Send 5c for catalogue. Henry Schiercke, 1034 72nd St., Brooklyn, N. Y. ARE you old at forty? See our advertisement on pag 116 of this issue. The Electro Thermal Company, 40: 36 Main Street, Steubenville, Ohio. EDUCATIONAL Character—New scientific system = reading people. Write H. E. Conlin, Dept. X, 21 John's Place, Buffalo, New York. FOR MEN AND WOMEN DETECTIVES—Work home or travel. unnecessary. Write, George Wagner, former Govern- ment Detective, 1968P, Broadway, New York. GENUINE Indian baskets, blankets Catalogue luc. Chelsex, apparatus, 10c. sensatioual Oaks Magical Co., Circulurs free’ FORMS to cast Experience and wampum— wholesue. Catalogue. Gilham, Kelseyville. California. _WANTED—Representatives in every factory in the United States. Popular Science Monthly, 225 West 39th Street, New York. FOR SALE—MISCELLANEOUS ROCKS and minerals for sale—hundreds of varieties— price list free. P. Zodac, 157 Wells St.. Peekskill. N. Y. More Money Making Opportunities on pages 6 to 20 BIG JOBS! $150 to $400 per month for men trained in auto, tractor and electrical fields. Youcanquali- fy after eight weeks in the McSweeny Schools——where you learn by working with real tools onreal jobs instead of studying from books. Special tuition offer, R. R. fare paid, 8 weeks board free. Get catalog. McSWEENY Auto, Tractor and Electrical SCHOOLS Two Big Schools 9th & Walnut, Cincinnati, O. 1815 E. 24th, Cleveland, OC. Dept. 267 STUDY AT HOME Become a lawyer-. trained men win igh — tions and big success In usi- ness and public ag ge ta w before en Be independentbe & ader. Lawyers 3,000. te 10,000 ) Annually We guide you ap by s ‘ou can train ors aid ome 8. ee of B. sands of successful students enrolled. y terms. aide” We furnish ‘all text material including four volume Law rary. Get our valuable 126-p ‘Law end *‘ *fvidenes" books FREE. Send for them-~ NOW. LaSalle Extension University, Dept. 983-L, Chicag®

Page 11

fail you at matter u now shown anship ars—it ‘OU— itifully 2-page ecome ” man E !! s many howing e Tam- general iy name estamp fully as U.S. A. ig! = ess in busi- e. Greatest than ever ndent—be @ Porat > a % 5 ; oe N what other profession can you start earning $50 to $75 a week right from the start? Barbering always has paid well, But now, with the added women’s trade it has become one of the highest paid professions—right on an equal footing with law, medicine and other lines that require years of college training. And you can now equip yourself for this dignified, clean, pleas- ant work in a few short weeks. You can have advantages over the ordinary barber. For under the famous Moler system you are taught new scientific methods that please men and women and never fail to attract extra business, You are made a specialist in your line—and you get a specialist’s pay. Experts Train You Right _ There isa Moler school near your home— thirty in all throughout the United States and Canada. Here expert instructors, recognized by the profession as the most xpert in the world, teach you the little secrets that will make you the most sought alter barber in your locality—and the best pest, In a few short weeks you become far vetter trained than the ordinary barber who ‘must spend two full years as an apprentice. Earn While You Learn aes under the Moler system it is possible ° ee earn money while you are learn- , Sieh ousands of young men acknowledge debt of gratitude for the help we have William McClintock, President Master Barbers’ Ass’n of Chicago and of the highest priced rented shop in the world, says, Moler’s, is Top man in my shop every week. I gladly recommend the Moler ace for men to © barbers.””--WM. McCLINTOCK. I Will Traim You in a Few Weeks— Set Up Your Shop in a New Easy Way POPULAR SCIENCE MONTHLY » te hh | | 2 + i ay ~ roprietor **‘My son, who learned at ystem as the b ul given them—help that enabled them to quickly step from the rut of low pay into a hundred dollar a week profession. Your Shop Equipped On Easy Terms We have even worked out a plan whereby you can, if you wish, own your own shop, on easy terms, You can own one of the author- ized Moler shops—part of a national institu- tion. One of our graduates writes, ‘“My shop has doubled its receipts since becoming one of the Moler chain shops.” Our national advertising gives you a tremendous advantage. $1,000 a month is not unusual for Moler shop owners. FREE BOOK Learn now how you can quickly become a Moler graduate—an expert in bobbing and marcelling, mechanical massage, electric hair cutting, scientific treatments and all barbering for men and women—and take this short cut to big pay. Other Moler graduates tell of earning $100 to $150 a week. Why not you? The best shops know that Moiler graduates mean extra business for them. A Moler diploma takes you anywhere. Our catalog tells you just how you can get this training, much cheaper than you would ever imagine, right in your own locality. This interesting book will be sent you free. Simply mail the coupon. But don’t delay a single day in finding out how you can easily and quickly enter this modern and well paid profession. Get the coupon in the first mail. New Scientific Method Taught Near Your Home Enables You to Cash On this Amazing Field That Has Been More Than Doubled by Demands of il . BARBERING 2: Now One of the \. Highest Paid /? *90t0°150 EVERY WEEK in Women | Pick Out the Moler | School Near You— MAIL COUPON (30 Branches in United States and Canada) New York, N. Y. Chicago, III. St. Louis, Mo. Kansas City, Mo. Cincinnati, O. Cleveland, O. Detroit, Mich. Denver, Colo. Omaha, Neb. Milwaukee, Wis. New Orleans, La. Atlanta, Ga. Memphis, Tenn. Dallas, Texas Houston, Texas San Antonio, Texas | Seattle, Wash. Tacoma, Wash. Spokane, Wash. TMOLER SYSTEM OF COLLEGES | Write N arc st Branch. "No Str i? t Addr neseg | | Needed.) | | Please send without obligation your Free | Booklet C, and Full information. | | 7 NAMIE So icc.ccoc addr nvenecaseele Seeseletewenae | PE en er ee Te ee eT | A ces anencemesanemeine enitsne omnum_,_

Page 12

12 FROM BUCK PRIVATE to$3500 in RADIO “When I enrolled with you I was a ‘buck pri- vate’ in the army. No sooner had I received my discharge than I opened a Radio Shop of my own in my home town. made over $3,500 in one year work- ing for myself. Now that I have the National Radio Institute course beneath my at, wouldn’t have missed it for a million dollars.”’ (Signed) JOHN P. ZINNO Corona, L. I.

INNO’S case is only one of hundreds. Every day letters pour into the offices of the National Radio Institute telling about the big money they are making as a result of this easy method of becoming radio expert at home in spare time.—‘‘l earn $83 a week and commission’—“'l cleaned up $405 in one month’”—‘Earned almost $1,000." These are only a few ex- periences of graduates of this famous radio school. Take advantage of these wonderful op- portunities to step into a big paying position in this great new field. Radio offers you an opportunity to travel and see the world, with all expenses paid, and a fine salary besides. Or you can stay at home and work up to a position paying up to $10,000 a year. One of our recent graduates secured a position one week after graduating paying a salary of $300 per month. Easy to Learn Radio at Home Radio is the ‘wonder-field” of today. Thousands of trained men are needed in this field. Salaries of $3000 to $10,000 are common. Employers are constantly writing to the National Radio Institute for Radio Salesmen, Radio Engineers, Radio Opera- tors, etc. They offer $50 to $300 a week for National Radio Institute graduates. There is a golden opportunity in Radio for You. Don't let it slip away. No matter how little you know about electricity or Radio, no matter what your age or education is, the National Radio Institute will guarantee to make a radio expert of you in a few months right in your own home. ‘The lessons are as easy A B C. Almost before you know it, you will be qualified for one of these big-pay positions. Send For Big Book Simply fill in and mail the coupon for this 32-page book, ‘Rich Rewards in Radio,” which will show you exactly how radio will double and treble your pay. You will see actual letters telling how hundreds have mastered Radio in a few months and now earn more money than they ever dreamed of. Make this your lucky day. Mail the coupon now. And say good-bye to hard times. "yap laiotghedlig aga hagpalemabanpaaleniagipapeaiaianlaa aes National Radio Institute, Dept. 12-JA, i » Washington, D. C H Send me the book, ‘‘Rich Rewards in Radio,"’ which tells ail about the opportunities in Radio, how spare time study at home will qualify me quickly as a Certified Radiotrician so I can get one of these splendid positions, and how your free Employment Service helps me to secure a good position.

POPULAR SCIENCE MONTHLY Money. Making ‘Opportunities 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 Bldg., Paducah, Ky. MOTION PICTURE BUSINESS WRITE photoplays; $50 each. Experience unneces- sary. Details free to beginners. Producer's League, 312 St. Louis. ORCHARDS AND FARM LANDS PECAN-ORANGE Groves “on the Gulf.” $10 monthly. Guaranteed care. Soon produce $500.00 yearly. Suburban Orchards, Dept. S, Biloxi, Mississippi. MR. ADVERTISER: Ask to-day for a copy of the “Quick-Action Advertising Fate 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. LANGUAGES WORLD-ROMIC System, Masterkey to all languages: Primers, $1.94 each language: Chinese, French, Spanish. Pronunciation-Tables, 30c. Dictionaries, grammars, 4.000 languages. Languoges, 8 West 40th, New York. STAMMERING ST-TUT-T-T-TERING und stummering cured ut home, Instructive booklet free. Walter McDonnell, 59 Poto- mac Bank Building, Washington, D. C. PATENTS FOR SALE PATIENT mouse and rat trap. Kecently patented in United States and Canada. For further information write Peter Covin, 3419 Butler Street, Pittsburgh, Pa. DOGS BEAUTIFUL vs mega sll _— pups cheap; 5OL Roekwood, Dalla DISTRICT MANAGERS WANTED WORLD'S fastest selling auto accessory! distributors wanted; write to day. G. L. Oiler Co., San Diego, California. WAN TED—Kepresentatives in every factory United States. oa Science Monthly, 225 39th Street, New York FOR INVENTORS INVENTORS’ Educator: 900 Mechanical ments. 50 Perpetual Motions. How to procure and sell patents. Mechanical Movements greatly assist Ine ventors, suggest new ideas. Explains how to select an attorney and avoid Patent Sharks. Price $1.50. Postage lree. ‘Albert E. Dieterich, 681 Ouray Building, Washing- ton, D. C. PATENTS—Write for Guide Books and “Record of Invention Blank.’’ Send model or sketch of your inven- tion for our free Examin: ution and Instructions. See advertisement on page 121. fictor J. Lvans & Co., 156 Ninth, Washington, D. C. CASHING In—If you have «a practical, usetul inven- tion to sell, patented or patent pending, write us promptly. American Patents Corporation, Barrister Building, Washington, D. C. TO SELL your patent, write me; experienced handling, immediate action. Address Arthur 8. Billings, Suite 401, Dekum Blidg., Vortland, Ore. GET Your Own ratents. Cutting, Campbell, Calif. INVENTIONS Commerci:lized. Patented or un- me Write Adam a isher Mfg Co., 183, St. Louis, Mo MODELS, Tools ears. Send sketch for estimate. Schmidt, 400 C anal ‘st New York. PATENT ATTORNEYS PATENTS Procured. Send sketch 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. Clareuce A. O’Brien, Registered Patent Lawyer, 1843 Security Bank Building. Directly across the street from Patent Office, Washington, D.C. See page 119. H. F. LOWENSTEIN, Technical expert. D.C.

Bulldogs,

County W., Spring

in the Test

Moves

Instructions $1, Cooper

Registered Patent Attorney. 817 McLachlen Building, Washington‘

PATENTS. Booklet free. Highest references. Best results. Promptness assured. Watson E. Colem:n, Patent Lawyer, 644 G Street, Washington, 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 Bldg., Washington, D. C., or Rooms 809-810 41 Park Row, New York. INVENTORS’ Guide free on request; gives valuable 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-Marks, Copyrights. Full information upon request. Moderate fees. Offices: Barrister Building, Washington: Leader Building, Cleveland; Monaenrock Plock, Chicago. MONROE MILLER, Ouray Bldg., Washington, D.C Patent Attorney; Mechanical, Electric: ul Expert. 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. L eae and Allwine, 232 Ouray Bldg... Washington. D.C. MR. ADV TEESE 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 More Money Making Opportunities on pages 6 to 20

$112,000 in prizes For Inventors What chance have you to win one of th prizes—some of them amounting to thoy. sands of dollars—which are now being offered for useful inventions? Here is ; glorious opportunity to earn a handsomp sum of money if you know what to do, Thousands surely will try for these prizes, but, as you know, those who have some training in practical invention have the best chance to win, A Fortune for You Big as these prizes are, they don’t begin to compare with the money some inventor have earned. Even simple things—like the humped hair-pin, the metal-tipped shoelace the pencil eraser—have brought their jn. ventors wealth and luxury. You, also, can develop your inventive instinct so it may bring you all that you have ever dreamed of. It doesn’t matter who you are, where you live, what you do—you have the ability to invent, which can be strengthened ané developed so it will be worth real money to you. 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 inven- tion, properly developed, may make you in- dependent for life! You Can Learn to Invent! If you ever had an idea for an invention, or if you would like to become a spare-time or profes- sional inventor, see what this fascinating new course can do for you. lifteen 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 inven- tion to get the greatest possible profits, and hun- dreds of other facts about invention worth a for tune to you.

| Write for this FREE BOOK A wonderful book explaining this fascinating course will be sent to you free. It explains the course 2 detail, and proves that you can easily train your mind to think inventively so you may become 2 successful inventor. It shows how +his course gives you, in a short time, a wealth of information which other inventors learned only after years of hard work and bitter experience. Get the advice of these fifteen famous inventors. Send for this book today. There is no cost or obligation. This bureal is not connected with patent attorneys or manus facturers. Our only work is to teach you how to develop your ideas so they will bring you big money. BUREAU OF INVENTIVE SCIENCE Dept. 29, Wisner Bldg. ROCHESTER, N. Y- Bureau of Inventive Science Dept. 29, Wisner Bldg., Rochester, * Y. ree Please send me without cost or obligation, your f Ls book, ‘‘The Science of Invention. WG oo nc coca cockcee eee eeensenee ewe <<oeoe AGEs a8 So Roca eet oS aes aan hee eae °

Page 13

a EIN to ventors like the shoelace heir in- lso, Can it may lreamed , Where > ability 1ed and money r mind an learn id make trouble ot know lions of ese un- ime you its and e inven- you in- 1 to hich cost f dollars. hing you © protect ur inven- and hun- th a for OOK ng course course in ‘ain your yecome 2 Irse gives on which of hard dvice of 3 book is ag Bee or manus u how to ig money. ENCE R, N. Ys N. Y- Get Into t PAYING BU in America !— POPULAR SCIENCE MONTHLY e BEST ESS I Will Teach You to Earn $3500 to $10,000 a Year in the Auto Field How much are you now making a week? Would you like to earn five times that much? Why not learn at home to boss the Big Pay jobs of the Automotive Industry? Thousands of positions paying from $75 to $200 a week are always open to trained men who know how to fill them. Free Auto Books This big five-volome Auto Refer- ence Library is FRLE to you when you start, 2200 pagcs, 2300 pictures, eharts, photos, ete, Finest Atto Library i in the world. Covers every sabject. Most valuable reference books. Alone wort th te cost of the Course, but ALL FREE! Free Tools and | Instruments — forrepair enti socket wrench set, special rachet Wrenches, extensions, ad: ‘pters and univers al’ joint, a valuatle ‘*Sono- scope’? for detecting enrine irreg- ularities, a volt-ammeter and @ Willard ‘Hy drometer for Battery Tk, and a setof high-grade feeler fi2g¢s. ‘This FREE outfit would ret § you $22 at retail, “Free Employ- _ ment Service Ei you FREE a life-lon help in ra ing you to get a job. Use it be- ti or after you graduate—any Te you w'sh—zs longas you wish. fi ough close touch with Manu- fatturers ard Garages we seldcm a © successfully place all stadents come to us for employment. I Train You at Your Home I can teach you to become an Automotive Expert—can give you at home —in one year or less—what it took me many years to learn in English fac- tories of Daimler and Rolls Royce and in American factories of Packard and Paige. I Guarantee Your Success! Satisfaction—or Money Back! Faith in yourself and ambition to learn is all you need. Are you willing to back yourself to win? All men are much alike from the head down. Invest a few dollars in your head and make it quadruple your pay, as it has done for thousands of my other students. You Can Earn Big Money— Wherever You Live Stay right at home—keep your present job—spend a few hours each week of your spare time—and I guarantee to make you an Auto Expert ready to go right into a Big Pay job. This trade knows no locality. Earn as You Learn Age and Lack of Education No Drawback You don’t have to be a wonder—just an ordinary, everyday ambitious man. And you don’t have to wait until you finish my course before you begin to earn. Earn as you learn. Almost from the start, you can begin to make good money on the side. Practical Instruction—Oldest Auto School Everything about my course is practical—easy to learn—and easy to apply. The lessons are intensely interesting, and I furnish FREE TOOLS so you can begin to apply them at once. This School is the Oldest and Best Home Study Auto School in America, turning out thousands of successful graduates each year. e es t+) Be a Big Paid Auto Expert Start today to guarantee your future success. Send for my Big Free Book “The Easy Way to Bigger Pay.’’ Actions count more than good inten- fi tions. Make the right move NOW. Fill out the Coupon! I'll show you This Free Book Tells the Whole Story Send for it Today! Here Is Your Big Opportunity If you have the ambition, I have the Training that will make you an Auto Expert. Get busy! Win success! Be a big man in this big pay field. Tom Plumridge, Chief Engineer @ Automotive Division, American School Dept. A-675 58th St. & Drexel! Ave., Chicago Send me your free book and other in- ‘ormation on how I can best get into the Big Pay Field. This request is to put me un- how to make more money than you ever dreamed of earning. 6 der no obligation. Tom Plumridge, Chief Engineer Automotive Division, American School

Page 14

14 GREER Will Heip You Scale the Salary Heights § Increase your Earning Power in the Auto _ Business

Garage Owners $300 to $5,000 per month

Auto & Truck Salesmen up to $20,000 per year

Head Auto Mechanic $150 to $500 per month

Garage Managers $150 to $350 per month

Electrical Experts rN $175 to $350 per month

Tire Experts $150 to $3§0 per month

Truck & Tractor Men $6.00 to $10.00 per day

Repairmen $12§ to $250 per month

POPULAR SCIENCE MONTHLY Money Making Opportunities | PATENT ATTORNEYS rALCN TS—Betore disclosing un invention ine 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 Irom manufacturers and others who are constantly writing us regarding the purchase or leasing of merito- rious patents sent upon request. See advertisement on

page 121. Victor J. Evans & Co., 937 Ninth, Washing- ton, D. C. UNPATENTED Ideas Can Be Sold. I tell you how and help you make the sale. righted 1923). Write W. Washington, D. C. “INVENTOR’S ADVISER” the valuable Patent book with 139 mechanical movements and illustrations, sent free upon request.—M. 8S. Labiner, Patent Attorney, 3 Park Row, New York. MILLIONS spent annually for 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. PATENTS, trade marks, copyrights. Prompt. per- sonal reliable service. Over 30 years’ active practice. Write for terms. Book free. Address E. G. Siggers, Box 1, N. U. Building. Weshington, D. C. LACEY Patent-Sense. ‘“Thce Book the inventor keeps.” Free particulars (Copy- T. Greene, 811 Jenifer Building,

ideas! Hundreds

lree. See page 114. PATENTS—My fees in or er nts. Advice book free. Frank Fuller, Washington, D.

INVENTORS: Send sketeh or mai for free opmion concerning patentable nature and exact cost of patent. Book, “How to Obtain a Pate a sent free. Tells what every inventor should know. Est: blished twenty-eight years. Highest references. Prompt service Reesonable charges. Chandlee & Chandlee, 478 Seventh, Washington. D>. <3.

THE PATENTOME. Impartial advice to Inventors ond Manufacturers. Mailed on request. Anderson & son, Patent & Trade Mark Lawyers, Established 1865, 636 F St., Washington, D. C AGENTS AND SALESMEN WANTED ONLY one sale a day means $200 per month! siles $1,000 per month. tetails $15.00. subtracts,

rive Marvelous new adding machine. Work equals $350 machine. Adds, multiplies, divides automatically. Speedy, necurate, durable, handsome. Five year guarantee. Offices, stores, factories, garages buy one to dozen. 4 fortune for live agents. Write quick for protected territory and free trial offer. Lightning Calculator Co., Dept. P, Grand Rapids, Michigan.

SALESMEN, can make $5.00 a day selling our c:len- dars, pencils, signs, advertising novelties, yuardsticks, whistles, ete. Liberal terms, Sells entire year. Fine sideline. Local and traveling agencies. Co., Dept. 309, South Bend, Indiana. $60-$200 A WEEK. Genuine Gold Letters for store windows. Easily applied. Free samples. Liberal offer to general agents. Metallic Letter Co., 434A North Clark, Chicago. Model Calendar

U. S. Census figures show that majority of wage earners earn less than $1500 per year.

SPECIAL Training Offer Don’t waste your life away in the lowsalary class! In 8 weeks I can prepare you to earn $35 to $100 per week and more as you pro- gress. I pay railroad fare toChicago and find you a home. If you need assistance while training I get you an earn-while-you-learn job. I GUARANTEE to get you an auto- mobile job at good pay after you learn. Or you can go in business for yourself. Special training group now forming. Be one of them. Rates reduced. Time pay- ments. Special kit of tools — 23 pieces — FREE. Every Auto, Truck and Tractor subject covered in actual shop work. Free RADIO COURSE. Day and evening in- struction. Choose your own time. I Have Trained 47,781 Men Of these men, trained by my staff of ex- perts under my personal direction, 80,245 are now in business for themselves. MAIL COUPON FOR ,FREE AUTO BOCK This book brings you my entire proposition and pages of valua- ble automobile information. Itis FREE. Get it NOW, while above offers are held open.

=—=-—-Mail This Today- — Erwin Greer, President zreer College of Automotive Engineering 2024 S.Wabash Ave., Dept. 2302; Chicago, IIl. Please send me FREE Book ‘ ‘How to Succeed in the Automobile Tractor Business’’ and special training offer. This request does not obligate me in any way.

oe Jo SpeSaneeesce veeeessesuenseccnces conse seeee Jj

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 (25¢e). Sold Clear and Rainy Days. No Cloth No Paste—No Attachment. (1) Rub keeps Windshield

Clear (48) Hours. Experience Unnecessary. Nulife Corporation, H»rtford, Conn. MAKE money silvering mirrors, all kinds plating, knives, spoons, auto headlights. Outfits furnished. Free Booklet. International Laboratories, Dept. 27, 311 Fifth Avenue, New York.

AGENTS—100% profits. Fast-selling novelty for Lodge members. Emblematic Belt Co., Dept. D., Ash- land, Ohio. BIG money and faust sales. Every owner buys gold initials for his iO orders daily auto. easy. You charge $1.50, make $1.44. org ation and samples free. i a

World Monogram Co., Dept. 25, Newark, KVERYBODY _ uses ecient 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. Sample 20c. Key check outfits, steel dies, key cases, etc. Service Sales Corporation, Shelby, Ohio. AGENTS—Clever Invention! pen a fountain pen.

Inkspoon makes every Fast office seller, big profit, demand increasing everywhere. Exclusive territory offered. Sample free. H. Marui Company, Tribune Building, New York.

AGENTS—Best seller; Jem Rubber Repair for tires and tubes; supersedes vulcanization at a saving of over 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, Ill. EVERY house a sile; Fast sellers; Particulars. mers Company, Desk No. 12, Hoboken, NM. 2: 31 BILLION, 650 million marks, re2zl German currency sa 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. 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 as side

Hel-

line. Commission. Patrick Label Co., 49F South Ave., Rochester, N. Y SELL union “jabel all-wool made-to-measure suits direct to wearer for $24. Tailors, 50. Scott System, 99 Bedford Street, Wholesale Boston, Mass.

More Money Making Opportunities on pages 6 to 20

LEARN Electricity

at i vinlieg a Stator i - Great School of COYNE

Earn $200 to $800 a month! New Enlarged Course I train you on everything from door-bells to power- plants—everything to make you a 650 to $200 a week EXPERT. You get complete PRACTICAL training in Circuits, House Wiring, D.C., A.C., Armature and Stator Winding, Drafting, Auto, Truck and Tractor Electricity, Battery Building and Repairing, and Radio. Everything to make = a thoroughly trained, BIG PAY, Electrical EXPE. CHICAGO The Electrical Center of the World The whole world of electricity is open to the COYNE trained Electrical Expert. Come toChicago—the Elec- trical Center of the W orld. I pay your fare. Get your training at COYNE—the oldest, largest and best school of practical electricity in the country—endorsed by Electrical Industry. I d lo not offer a number of individual courses — I give you just one complete course sothat you will bean Electrical Expert capable of commanding big g pay. You can become an Expert and get big TT kd in ANY branchof electricity if you come to COYNE Learnin 12 Weeks! NOT A CORRESPONDENCE SCHOOL Nobooks or useless theory. I train you on the greatest outlay of electrical agpere country. I give you FRE aratus of any institution inthe .E complete Radio and Auto- motive courses. I also give youFREE a Life Member- ship which enables you to stay longer if you wantor to come back et any time and take ay So new work which is constantly being installed to the most modern at all eep my school times. You Don’t Need Education COYNE gives you educa- or Experience tion and experience by actual work—that’s why you don’t need education or experience to start with. Earn While You Learn! I help students to secure jobs to earn a good part of their living expenses while studying. Send Coupon Now Don’t delay a minute—send that coupon right now for my big free ae and full particulars of special otter, ACT NO Free R. R. Fare to Chicago Come to Chicago—the co aod beready for BiG MONEY inte weeks! resort city— eatest summer ‘Endorsed. by: Electrical Industry

1300-1310 W. Harrison St., Dept. 6-136 Chicago Gf Coyne Electricz} School, Dept. 6-136 1300-1310 W. Harrison St., Chicago H. C. LEWIS, Pres. free your big new new catalog and full particulars on free railroad fare offer and two free courses. Mr. Dear Sir:—Please send me

Cee A BO

ni Cine iet . “SS, ee

Page 15

POPULAR SCIENCE MONTHLY 7] naga oP ty gach Jo Opportunity Ha it Worth While > AVE you ever stopped to consider

whether you are building a future ing Oo your present job or merely wasting yourtime? ig! The mere fact that you are working long, hard ry hours and getting a living wage for doing what 9 . the boss Zells you to do, doesn’t mean a thing. power. As a matter of fact those who work the hard- ningin } = = est are Often the greatest failures. You can | actor prove that by merely looking around you—by com- rained, paring the wages of the laborers with the salaries of the experts. The first get paid only for what they do; Get These Big Pay-Raising Books 9 the others get paid for what they know. And because The eight big volumes of the ‘Cyclopedia of Applied Electricity” there are more laborers than experts in everyline of were published by the American Technical Society to help those er z business, the trained men get a larger share of the who are anxious to increase their knowledge and pay through i things that make life worthwhile. pleasant study at home. These remarkable books have helped t Wh N t P f Bi Pp 9 oe of ambitious men who wanted to learn the real facts OYNE t about their work but were unable to devote time and money to a ‘ : Ay INO : repare or a big ay Job * correspondence course or special school training. With the aid of nd best ; Just look at the illustratiou above and ask yourself—“Which Job _ these books you can quickly acquire a knowledge of electricity in — Will J Hold at 40?’ There’s no doubt as to which job you'd like all its branches. They are pleasant to study, easy to understand, mplete to hold; and there’s no reason why you can’t attain and hold the _ highly authoritative and thoroughly up-to-date. You will find Depert job you'd like. Plenty of big pay jobs are waiting them a handy guide in your work, a ready solution latte ; for trained men in the electrical field; but you'll for your problems and a dependable help to a better € i need more than overalls, an oil can and strong . job and bigger pay. Just read the list of titles and cS$ ui arms in order to get one. What you will need—and FREE Consulting description and ask yourself if you can afford to OL i what you can quickly acquire—is a thorough knowl- Membership be without them. Then mail the coupon today! eatest . edge of every important phase of electrical work, Rack of these eight hic velamesel inthe k That knowledge is now available in these eight big i Electricity” stands astaf Send No Money-Read Them5 Days aber S volumes of “Applied Electricity.” The coupon will vise and help you until you are ex- aa d i cad : —s f put them into your home for study, reference and pert yourself. This expert advisory It isn’t necessary to send a cent in advance in school B help at a total cost of only 10 cents a day. Why || ican Tes neal Soricty foraiinca || order to get these eight big books and the Free not send for them today and prevare for a big pay time to those who mail the speci-1 Consulting Membership explained in the panel. ion icb as an electrical expert? work and referencelibrary at home, Just mail the special coupon. When the books educa- ; cr gd ged aga tiene 20 ex- arrive, deposit only $3 with the postman and on 8 big’pay job, in the electrical he id. examine them 5 full days. If you are convinced lassen ths Weemation por ose, they can help you, send us $3 monthly for nine nm? You can use this service daily if months; otherwise you may return them and get art of you See your money. Don’t speculate as to “which job you MAIL will hold at 40”— mail the coupon today and let Ww these famous books help you make a future in THIS the electrical field. American Technica! Society, ae TODAY || Devt-£93; Chicago, U.S.A. = [ SPECIAL 5 DAY EXAMINATION COUPON a _— : American Technical Society | Dept. £93, Chicago, U.S.A. | a8 2 and E . Please send me, postpaid, | the eight volumes of “Applied Electricity,” I will deposit $3 with | | the postman on arrival and, if] decide to keep the books, will send cago you $3 monthly for nine —. nh ye Os a eS | "Ss 4 2y tis Ss is entitles me é “ " ; | Po eee Membership in the ‘Society, which I can use daily if I | like. nd mel | Name | nD f 4 7 } Eight Big Street | Volumes—3800 | ene ages—3000 Pictures— City State — = | Printed on Fine Paper—Attrac- | - tively Bound—Stamped in Gold and idexed for Ready Reference—All yours or Only 10c a Day. Mail the coupon. essnee = Employed by - —$—__— |

Page 16

‘“‘There’s one man we're going to keep” “Ed Wilson, there, is one of the most ambitious men in the plant. I notice that he never fools away his spare time. He studies his International Correspondence Schools course every chance he gets. “It’s been the making of him , too. He hasn’t been here nearly so long as Tom Downey, who was laid off yesterday, but he knows ten times as much about this busi- ness. “Tm going to give him Tom’s . b . . Ss 9 job at a raise in salary. He’s the kind of man we want around here.”

OW do you stand in your shop or office? Are you an Ed Wilson or a Tom Downey? Are you going up? Or down? No matter where you live, the Interna- tional Correspondence Schools will come to you. No matter what your handicaps or how small your means, we have a plan to meet your circumstances. No matter how limited your previous education, the simply- written, wonderfully-illustrated I. C. S. textbooks make it easy to learn. This is all we ask: Without cost, without obligating yourself in any way, put it up to us to prove how we can help you. Just mark and mail this coupon, ees comme SS ee ae — me ae INTERNATIONAL CORRESPONDENCE. SCHOOLS Box 7610-D,. Scranton, 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 Jindustrial Management _] Advertising Personnel Organization (_}] Better Letters [} Traffic Management [] Show Card Lettering Business Law _] Stenography and Typing Banking and Banking Law |] Business English Accountancy (including C.P.A.) 0 Civil Service Nicholson Cost Accounting |} Railway Mail Clerk Bookkeeping [_} Common School Subjects Private Secretary [| High School Subjects Spanish 0) French Lj illustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering r- Architect Electric Lighting [] Architects’ Blue Prints Mechanical Engineer 0 Contractor and Builder Mechanical Draftsman -} Architectural Draftsman OOMachine Shop Practice + Concrete Builder oy eed sg: sora [] Structural Engineer 3as Engine Operating 7 Chemistry Phe (Civil Engineer pear AL! page Aut bile Work Ppateiaiture and Mapping Ly Automobile Wort

OOOOOUUOICI Metallurgy O Mining Airplane Engines ‘4 > 1 or Steam Engineering D Radio Agriculture and Poultry Mathematics

es ne ener treme Address.... OE ia neil etl See MIDI Sane s= Gana ct Pepion.susansssncbsssncoasvo'eapses gs lubaesm uanaciecoaee Persons residing in Canada should send this. coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada

POPULAR SCIENCE MONTELY Money Making Opportunities AGENTS AND SALESMEN WANTLD $10 to $25 Daily, No Investment. Free outfit. Best values. Largest commissions. World Raincoat Company, 659-S. Morris Park Ave., New York. MAKE $17 day—Finest extracts, food products, toilet preparations, household necessities. Credit; sample case free. Write for amazing offer. Perkins Products, 13-26, Hastings, Nebr. WE start you without a dollar. fumes, toilet goods. I¢xperience 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 Blain flavoring extracts in every locality, wholesile and retail; new selling system; free samples to public and other unique — Address Annie Blain Co., New Brunswick, N. | WONDERFUL discovery.

Soaps, extracts, per-

Charges batteries in ten

minutes. Gallon free to agents. Radiolite Co., St. Paul, Minn. FREE Copy—Big Fun Magazine. Representatives

wanted. Fin-Ko, 944-P Clark, Toledo, O POLMET—The Wonderful Polishing Cloth that eleans all metals without liquid, paste or powder. Ap- proved by “Good Housekeeping” and ‘*Modern Priscilla” sells fast at 25c. Sample Free. F. C. Gale, 15 Edinboro t., Boston. AGENTS—Household necessity, sells quickly. profits. Square deal. Detroit, Mich. $10.00 DAILY easily retails 25ce. Send 10c Wilmerding, Penna. EARN $10 daily silvering mirrors, finishing metal ware, headlights, Outfits furnished. I.

Large Premier Mfg. Company, Dept. 5,

made selling Needle Cases; for simple. Mail Order House,

plating and re- chandeliers, bedsteads, Decie Laboratories, 1133 Broad-

way, New York. 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., Chieogo. 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 ‘polis 1es Automobiles. Furni- ture, Pianos, Retails 50¢.—Costs 16c. Sample Free. Nulife (H) Sponge, Hartford, Conn. BIG money and fast s les. k:very owner buys gold initials for his auto. You charge $1.50; make $1.35. Ten orders daily easy. Write for particulars and free simples. American Monogram Co., Dept. 47, East Orange, New Jersey. AGE VTS: Bill Omeis, $5000.00 during

F just an ordinary fellow, made over 1923 selling our $1.50 kitchen spec ialty. He is now a district manager. We are offer- ing you the same proposition—: in opportunity as big as you want to make it. You e1n do what Omeis did. Write today, M. H. Tyler Mtg. Co., Dept. P-1. Muncie, Ind. ~ BU ILD pe rmanent business. Men's, Women’s, Chil- dren's guaranteed shoes direct to wearer. A. P. Condon, Sales Manager Allen Shoe Co., 110 Summer, Boston. BEST proposition in the Speciclty_ ficld. Perry Lykoil Paintings. Photo Medallions, and Novelties have pn» equal, Every interview _means a sole. 600% profit. Write for details. Perry Photo Novelty Corporation, Set. PS7, 360 Bowery, New York TAILORING agents—50 goo! men wanted, who can earn $50 weekly and up. Our line contains 220 biz value all wool fabrics to retail »t $25 to $47.50 for suits and overcoats. Your protit $5 to $9.50 in advance. Big 6 x 9 swatch outfit free. Ref. req. R. B. Ferrin, Mer., }’. O. Box 1097, Chicago. RUMMAGE Sales make $50.00 daily. Offer wonderful values. We st: art you. “W holesale Distributors, "* Dept. 34 609 Division Strect, Chicago. SELL Pearl Necklaces. 500% profit.

I:verybody 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 Bell Gum Machine Deals. Six balls for three cents. 100% profit. Cuts iurnished. Milwaukee, Wis. GET our plan for monozramming 2utomobiles, trucks, hand luggage and all similar articles by transfer method; experience unnecessiry; exception: l profits. Motorists’ Accessories Company, Mansficld, Ohio. GET our free sample case toilet articles, perfumes and specialties. Wonderfully profitable. La Derma Co., Dept. F, St. Louis, Missouri. Purity Gum Co., 273-20th St.

You too pam make a aweek To earnest men every. where we offer a wonderfuj opportunity taking orders for our fine, pure wool suits and overcoats, regular $55 values all at the one low price of $31.75. Our values are so re. markable they sell on sight, You get your commissions jn ‘ [advance, simply take the or. ders, and we deliver and collect. Our salesmen are making $50 to $125 a week and even more,

“I had no experi- enceinselling before going with GOOD- | No experience is needed WEAR. Now I/and spare time will do, make $125 a week regularly. I believe that any manwho’ll work can do the same and would ad- vise every man who wants a fine pay- ing jcb ad write to We teach and train you, sup. ply the finest selling outfit in America, big 6x9 cloth sam. ples and everything else you need, all packed in a beautiful carrying case. If you want to get into a high-class business, Z make big money, and be inde. GOODWEAR. pendent, write for full informa. ae Birdakis | tion today. Address Dept. 175, GOODWEAR Chicago, Inc. West Adams St. at Peoria Chicago Please serd me complete information about your Line and the opportunity you offer,

175 Name... <P P POOH SEES EE OE SEHEHEHDS HEHEHE FEEEE Addres8...ccccccccencccccccccescccececcccccce SEMEN bose aes sieleieisioisinisieina (c(t eID s nisin sane

LEARN BY DOING aan ¢ et 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 cataios THE NEW YORK ELECTRICAL SCHOOL 40 West 17th St., New York City Open All Summer

AGENTS: Big protits. letters made. Easily applied. Particulars free. Staibrite Avenue, New York. AGENTS—S$75.00 Weekly Selling Nustile Guaranteed Best and cheapest window Dime brings five samples. Company, 1115 Second

Hosiery. Your pay daily. You write orders, we deliver and collect. Specizl monthly bonus. Sample outfit furnished. Nustile Hosiery Mills, Dept. 400, Philadel- phia, Penna. 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 declers. Employ sub agents. Exclusive territory. Make over 100% profit. S. Bernhardt, 148 Chambers Street, New York. SUCCEED with your own procaucts—lormulss, Processes, Trade-Secrets. Dificrent, ctepend: wri p ofit— able. Catalog free. C Thexly Co., Wrs'.., NEW “Dan‘i-Post”’ Ro d Sitn. Latest oe in sign construction. E.sily instelled. Any color. No restricted territory. Newton Mig. Co., Sign Dept., Newton, Ia. SALESMEN: Earn $50.00 weekly selling custom made shirts at ready-made shirt prices. 100 latest pat- terns; price $2.95 up. Shirts individually cut. Uncon- ditional guarantee. Custom Bilt Shirt ‘Company, 538 Brovdway, N. Y.

AGENTS Coining Money. $1.40 profit on every $1.50 sole. Monograming Automobiles. Free samples. Worces- ter Monogram Co., Worcester. M»ss. More Money Making Opportunities on pages 6 to 20

aa a. Week FOR DRAWING “G Br: Commercial art is a necessity to mod- ern business. If you like to draw, de- , & velop your talent in a practical way. Goo Me commercial artists earn $100 a week, end more. Many Federal Students command $ 50 a week atter a short period of practical work. Learn Quickly at Home ie ‘*Federal’” Master Course teaches you bs Ws mail in your spare tire No expe rience needed. Read ‘‘Your F uture.”’ A splendid book tell- Ss ing all about this ay and the succe Federal _ stud : Send 6c In ste stating age. ry 7 ee ~ Com’! Designing ey 1354 Federal Schools Bldg, + Minneapolis, Minn:

remarkable course, for it today, kir Federal School cf x

Page 17

‘ke ek every- iderful ders for ute ond Values Price of re SO re. n sight, sions in the or. A collect. cing $50 en more, needed ill do, OU, sup. ig outfit oth sam. else you eautiful : want to usiness, be inde. informa. ept. 175. Inc. hicago out your 175 oeeresee eerecete ED ING of all CITY ictice nost and for trade Used uction lay ge catalog ORK CHOOL York City mer Money Making Opportunities AGENTS AND SALESMEN WANTFD SS Wk Start You in Business—No Capital Required. Monogramming Automobiles, Luggage, Windows, Wag- ons. Six Initials Bring $1.50—Costs You Only p Transferred as Easy as Applying Stamps on Envelopes. No License. No Experience. ‘Samples Free.” NuLife (H) Monogram Works, Hertford, Conn. 310 TO $50 a day Cleaning Carpets, Rugs, Clothes. Get in Business; do it now. Don't pass this up; this is your opportunity. We will send Cleaner and direct you for $1.00. Agents wanted. A. D. Cleaners, 1403 11th Ave., Oakland, Calif. AGENTS: Our guaranteed 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. SELL Radio Crystal Receiving Sets. Guaranteed sample and working outfit to agents ($1.00) prepaid. Southern Co., Box 217-P, Weshington, D. C. AGENTS: Three neckties boxed singly for $1.00— Retail $2.00. Cash with order. Maxwell, 401 Searle Bldg., Rochester, N. Y. BIG Profits witu Exclusive Territory—$50 to $100 weekly easy. More hes often been made in one day's work. A hot or cold running water bath equipment for any tome at only $7.50. No plumbing or water works required. Investigate. Send no money. Write today, Sanitory Sunply Co., 722 Allen Building, Toleco, Ohio. EVERY tord owncr in the world wants this! The Hamer Visible Vaporizer guarantees incrersed 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. Det: ils 2nd proofs. Visible V-norizer, Dept. 17, Chemberlrin, S. D. $10 DAILY silvering mirrors, plating and refinishing lamps. reflectors, autos, beds, chandeliers by new method. Outfits 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 $100 weekly and bonus. Madison Mills, 564 Broadway, New York. EASY money applying monograms on Automobiles anyone can do it. Simply transferring gold Decalcomania Initials. Takes five minutes make $1.50, cost 5c. Sample Free. Ralco, 327 Harrison Ave., Boston, Mass. GET exclusive state rights sell new auto product. Costs 50c including literature, sells $3.75. Samples to try sales possibilities which retail for $11.25 free to agents. Mickman Co., St. Paul, Minn. WANTED—Tailoring salesmen make $60.00 to $125.00 r week—Set your own profit on each sale. We show largest assortment, guaranteed all wool suitings and over- coatings, retailing for $25.00 to $45.00. Our made-to- order clothes are highest quality and lowest in price. Absolute satisfaction guaranteed or no sale. your opportunity—you can make big money—a hustler can make over $50.00 a day. Write for big sample equip- ment to be shipped prepaid and please give all informa- tion about yourself. Address R. B. Boyce, Sales Mana- ger, Box 483, Chicago, Ml. 15 Personal Engraved Christmas Cards $1.25, 30% Profit. Soliciting Folder 10c. Wolf, Printer, Lawndule, Philadelphia. SALESMAN: If you think in terms of $6000 the first year write me personally. Strong line for retail stores. Nationally advertised. Established concern has unusual opportunity. Liberal weekly advance to _ producer. Geo. R. Williams, Megr., 1922 Euclid Avenue, Cleveland, Ohio, Dept. 201. WHY not sell us your spare time, $2 an hour—S$19.70 daily exsy for full time, Introducing New Style Guaran- teed Hosiery 57 styles—37 colors—No capital or ex- perience required—Just write orders. We deliver and collect—Your pay daily, also monthly bonus. Free auto offer besiles. Elegant outfit furnished—All colors— grades including silks—lisles—wools. Macochee Textile Como ny, Room 1529, Cincinnati, Ohio. SALESMAN—Manufacturer of unique line specialties selling merchants, factories. Building permanent sales organization, attractive plan. Write pocket sample. Greene Corporation, Mt. Morris, N. Y. $6 to $15 doily—year around position, monthly bonus besides. Grooy made $499.50 in 30 days, Cregan $443.03, Whiteside $435.00, Robey $352.00, Bickel $320.91. No experience or capital required. Exclusive patented necessity—millions of prospects, homes, stores, schools, factories, auto and truck owners. Spare time satisfactory, we deliver and coilect also carry_accounts. Cash in on our advertising and approval by National Board and big users, Our original new plans produce results. Write quick for full details. The Fyr-Fyter Co., 199 Fyr-Fyter Bldg., Dayton, Ohio. A Business of Your Own. Make sparkling Glass Name and number plates, medallions, checkerboards, signs. Big illustrated Book Free. EF. Palmer, 513 Wooster, O. FASTEST Selling specialty. Latest style shoes and moccasins. Fit the whole family. Big commissions. Repeat orders, Permanent business. Prompt promotion. Free samples if you qualify. Apply Crawford Treat, Bengor, Maine. MAKE 875.00 a week and up selling our fine made- to-measure, all-wool suits at $31.50 retail, direct to wearer. siggest values—positively sell on sight. Biggest com- m.ssions, paid in advance. We attend to delivery and colletions. 6x9 swatch samples furnished Free. W. Z. Gibson, Ine., Dent. 161, W. Horrison St., Chicago. SALASMEN—Here’s a legitimate profitable business opening as distributor for household article that is proved Success. Thousinds in use. Nationally advertised. No investment proposition, no ‘‘back door’’ job, but per- rmpe business with steady profits. Write for proposi- lon giving details of your past business experience. CFSCO-14 N. 10th St., Richmond, Ind. eens Profits. Rubber Specialties. Fifty fast sellers. Beoody needs and buys. $50 weekly easily made. B.& G. Rubber Co.. Dent. 629 Pittsburgh, Pa. Nee you old at forty? See our advertisement on poe M of this issue. The Electro Thermal Company, 4036 Main St., Steubenville, Ohio. SALESMAN: If you think in terms of $6000 the first Grr? Write me personally. Strong line for retail stores. ationally advertised. Established concern has unusual ae wis oe weekly advance to =. 0. R. Williams, Megr., 1922 AV , Cleveland, Ohio, Dept. 207 gr., 1922 Euclid Avenue evelanc More Money Making Opportunities on pages 6 to 20 This ic. POPULAR SCIENCE MONTHLY 17 ERVE EXHAUSTION How Nerve Abuse Wrecks Health by PAUL von BOECKMANN Lecturer and Author of numerous books and treatises on Mental and Physical Energy, Respiration, Psycholocy and Nerve Culture HERE is but one malady more ter- rible than Nerve Exhaustion, and that is its kin, Insanity. Only those who have passed through a siege of Nerve Exhaustion can understand the true meaning of this statement. It is HELL; no other word can express it. At first, the vic- tim is afraid he will die, and as it grips him deeper, he is afraid he will not die; so great is his mental torture. He becomes panic- stricken and irresolute. A sickening sensa- tion of weakness and helplessness overcomes him, He becomes obsessed with the thought of self-destruction. Nerve Exhaustion is due to nerve strain. There is no other cause for it. In men, nerve exhaustion can generally be traced to excesses and vices, although the strain of intense concentration and the worries of business life are often the chief factors. In women, Nerve Exhaustion is due mainly to over active emotions. Especially in their marital, domestic and kindred relations do -women subject their emotions to constant upheavals. Indeed, we are all under severe nerve strain because of the mile-a-minute life we are leading. And no man or woman is so strong as to be immune to this strain. Nerve Exhaustion is not a malady that comes suddenly, yet its symptoms are un- mistakable. It does not manifest itself, as many think, in twitching muscles and trembling hands. The majority of sufferers from nerves seem strong and healthy, and may have not a tremor in their body, yet inwardly their nerves are in a turmoil and are undermining the entire bodily organism. The symptoms of Nerve Exhaustion vary according to individual characteristics, but the development is usually as follows: First Stage: lack of energy and endurance; that “tired feeling.’’ Second Stage: Nervousness; restlessness; sleeplessness, irritability; de- cline in sex force; loss of hair, nervous in- digestion; sour stomach: gas in bowels; con- stipation; irregular heart; poor memory; lack of mental endurance; dizziness; headache; backache; neuritis, rheumatism, and other pains. Third Stage: Serious mental dis- turbances; fear, undue worry; melancholia; dangerous organic disturbances; suicidal tendencies; and in extreme cases, insanity. If only a few of the symptoms mentioned apply to you, especially those indicating men- tal turmoil, you may be sure that your nerves are at fault—that you have exhausted your Nerve Force. Perhaps you have chased from doctor to doctor seeking relief for a mysterious ‘‘some- thing the matter with you.’’ Each doctor tells you that there 1s nothing the matter with you; that every organ is perfect. But you know there is something the matter. You feel it, and you act it. You are tired, dizzy, cannot sleep, cannot digest your food, and you have pains here and there. You are told you are “run down,’’ and need a rest. Your doctor may pre- scribe a drug—a nerve stimulant or sedative. Leave nerve tonics aione. It is like making a tired horse run by towing him behind an automobile. And don’t be deceived into believing that some magic system of physical exercise can restore the nerves. It may develop your muscle but it does so at the expense of the nerves, as thousands of athletes have learned through bitter experience. The cure of weak and deranged nerves must | BEER o I Ry tr RO: PAUL VON BOECKMANN Author of Nerve Force and various other books on Health, Psychology, Breathing, Hygiene and kindred subjects, many of which have been translated into foreign languages. have for its basis an understanding of how the nerves are affected by various abuses and strains. It demands an understanding of cer- tain simple laws in mental and physical hy- giene, mental control, relaxation, and how to develop immunity to the many strains of everyday life. Through the application of this knowledge, the most advanced case of Nerve Exhaustion can be corrected. I have made a life study of the mental and physical characteristics of nervous people, having treated more cases of ‘‘Nerves”’ during the past 25 years than any other man in the world (over 100,000 cases). The result of this vast experience is em- bodied in a 64-page book, entitled ‘‘Nerve Force,”’ a book that is essentially intended to teach how to care for the nerves and Low to apply simple methods for their restoration. It includes important information on the application of deep breathing as a remedial agent. The cost of the book is only 25 cents, coin or stamps. Address me—Paul von Boeckmann, Studio 164, 110 West 40 St., New York City. This book will enable you to diagnose your troubles understandingly. The facts pre- sented will prove a revelation to you and the advice will be of incalculable value whether you have had trouble with your nerves or not. Your nerves are the most precious pos- session you have. Through them you ex- perience all that makes life worth living, for to be dull-nerved means to be dull-brained, insensible to the higher phases of life—love, moral courage, ambition, and temperament. The finer your brain is, the finer and more delicate is your nervous system, and the more imperative it is that you care for your nerves. ‘Nerve Force’ is not an advertisement of any treatment I may have to offer. This is proved by the fact that large corporations have bought and are buying this book from me by the hundreds and thousands for circu- lation among their employees—Efficiency. Physicians recommend the book to their patients—Health. Ministers recommend it from the pulpit—Nerve Control, Happiness. Never before has so great a mass of valuable information been presented in so few words. It will enable you to understand your Nerves, your Mind, your Emotions, and your Body. Over a million copies have been sold during the past fifteen years.

Page 18

“dental mechanics” ITH my training any good mechanic now earning less than $50 a week can in 4 months become a Dental Laboratory Expert and make from $3 per hour up to $10,000 per year! mechanic” will tell you there are more big-pay jobs than experts to fill them. So I invite every ambitious man, regardless of age or education, to write for my sensational mail coupon for complete information or how you can prepare for salary of $100 a week or more in double-quick time and at trifling cost. Fascinating Mechanical Profession! 70,000 Dentists in the U. S., but only 300 Laboratories to do their work. More Laboratories needed everywhere, more all-round Experts trained as I will train you, to master every branch of Dental ‘‘Mechanics”—vulcanite plates, crowns, fixed and removable bridge-work, metal base dentures, parallel removable bridges, etc. Only training offer school on earth with ethical practising Dentist supplying clinical and actual cases. Look How I Help You! I will make it worth your while to start now to get ready for the big oppor- tunities in high-salaried positions, and to go into business for yourself in a good location THIS FALL. R. R. Fare to Chica- go or Detroit FREE. Big $50 Outfit of ® Tools, Instruments @—\ and Supplies FREE. Free ZEAE" consulting service. Free Diploma. Post Graduate Course also FREE. Free Employment Bu- reau. We help you find work to pay expenses while here (if desired) and help you securea big-pay position when you graduate. H. A. McCarrie, Director McCarrie School of Mechanical Dentistry Dept. 892-1, 1338 S. Michigan Ave., Chicago Without obligation please send me your FREE R. R. Fare offer, your Free $50 Outfit offer and Free catalog with complete information about how I may become a Dental Laboratory Expert. a oe ies POPULAR SCIENCE MONTHLY Every McCarrie-trained ‘dental Learn By Doing Actual DentalLahoratoryJohs! No classes or text-books. with ACTUAL instruction guaranteed. All individual instruction instruments and materials on clinical jobs. My personal Come to Chicago or Detroit where I have built up and equipped the largest Dental Laboratory schools in the world. McCarrie graduates, men and women, preferred by employers. My graduates are successful and I guarantee you will be, too. FREEVSS BOOK S822 is p- u NEW portunities waiting for you when you are a McCarrie-trained Dental Laboratory Expert. Explains my rapid, practical method of training you for big-pay positions or to open your own laboratory. Contains my free offers of FREE Railroad Fare and $50 Outfit. Write me personally right away! H. A. McCARRIE, Director McCARRIE SCHOOL OF MECHANICAL DENTISTRY Dept. 802-1, 1338 S. Michigan Ave., Chicago standard tools, laboratory Tells you all about week! \\ Loan me part of your goate time, % end 5 prepare you in a few months or the big opportunities in the Auto asiness. My original copyrighted ePray instrucfion covers Welding, Garage Management, etc. § TRAIN YOU AT HOME! ss Get my training and learn to Boss the job? E.rn Auto-Experis’ big pay. As_ Directi Engineer of a Auto Snopes snow what ou ne suce: TO YOU! RIGHT IN YOUROWN HOME! Every ram, youn or eld, edocated or not wil man, young or old, educa’ wi y, road to SUCCESS in sore cake WRTTEYOR TT TODAS" * ! testing and repair outfit to every =. student this month. B. W. Cooke, Directing Engineer Chicare Ante Shops—Dept. 625 1553 W. Madison St., Chicage Why Good Dancers Are Popular_#) EVERYONE admires and wants \_ 44 to dance with the person who knows the latest steps. There is no need of being a wallflower! By my remarkable new easy method any- one can learn the newest dances at home in a few hours. uch less expensive than from a_ personal teacher, No music or partner 4 simple even a child can ge learn quickly. 120,000 have fearned dancing by own success is 5 I ickly and easily make oo an accomplished dancer, I will send yu v esson in Fox Trot, Secret of Leading. 5 rh le successfully. The Correct Dancing Position ow to Gain confid ee ‘0 pay the cost of mailing, handling, etc., send 25c. Learn in private—surprise your friends. Act ic now and a eT 800nN. ARTHUR MURRAY, Studio 253, 290 Broadway, New York * $15. Money Making Opportunities AGENTS AND SALESMEN —_————_—_—————— GET into the tailoring game—one of the most profit- able of all lines in the selling field. Experience isn’t neces. sary, and spare time will do. We teach you how to seli our line, and supply you with everything necessary to go out and make from $10 to $20 a day from the very first day. Our selling outfit is the finest ever gotten together and shows more than 100 large samples of finest quality Virgin Wool Suitings, many of them our own exclusive patterns. Also a big showing of high-class heavy-weight overcoatings. You do no delivering with our line. You just write your orders. We do the rest. Your profits run big and you get them cash with order. If you want to get into this most profitable business, write us quick. Address Dept. 178, GOODWEAR Chicago, Inc., Chicago. 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 Profit:bly.’’ You'd like to know wouldn't you? Manager, Classified Advertising, Popular Science Monthly, 250 Fourth Avenue, New York. BUSINESS OPPORTUNITIES PATENTS Procured; Trade Muras s.egistereu—A comprehensive, experienced, prompt service for the pro- tection 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 Bldg., Washington, D. C., or 2276-Z Woolworth Bldg., New York. UNLIMITED Possibilities, making metal toys at ome. No experience required. Particulars free. New Specialty Co., 448 E. 79th St., New York. ARTIFICIAL Marble, sanitary flooring instruction, ornamental casting, concrete plaster, papier-mache decorations, garden furniture, stituary. Rubber moulds, Electrometallurgy, particulars and 200 illustrations free. Chris. Mahler, Huntington, N. Y. WE start you in business, furnishing everything; men and women, $80.00 to $100.00 weekly operating our “New System Specialty Candy Factories’ anywhere. Oppor- tunity lifetime; booklet free. W. Hillyer Ragsdale, Drawer 19, East Orange, N. J. STOP plodding! Be successful. Operate a tire repuir shop. Make big profits in any locality. We teach you and furnish complete equipments, $100 up. Book of Opportu- nity free. Haywood’s, 1306 South Oakley Avenue, Chicago. USED correspondence courses sold, rented and ex- changed. List free. (Courses bought.) Lee Mountain, Pisgah, Alabama, FREE Book. Operate little Mail Order Business, home evenings. Pier 786, Cortlandt St., N. Y. HOW O. T. H. 8. made $110.00 in 2% hours. B. R. Co., Oblong, Ill. INCH Display Advertisement 166 Magazines Turice Year $ v. Wood's Popular Service, Atlantic City, PATENTS—Write for our Guide Books and “Record of Invention Blank” before disclosing inventions. Send model or sketch of your invention for our free Examina- tion and Instructions. Terms Reasonable. Sce :civer- tisement on page 121. Victor J. Evans & Co., 190 Ninth, Washington, D. C. LEARN the collection business. Good! income; quick results. Interesting booklet, ‘Skillful Collecting,” free, oy Collector's Association, Science Building, New- ark, Ohio. BECOMi:: A loot Correctionist. A New Profession, not medical nor chiropody. All the trite you can attend to; many are making $3000 to $10,000 yearly, easy terms for training by mail, no further capital needed or guods to buy, no agency or soliciting. Address Stephenson Labora- tory, 10 Back Bay, Boston, Mass. SUCCEED with your own products—?orimuilas, Processes, Trade-Secrets. Different, dependable, profit- able. Catalog free. C. Thaxly Co., Wash., D. C. GO 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. A WASHINGTON, D. C., office will digniiy and in- crease your business. Use ours. Expense, sm°-ll; benefits, great. Capital Service Company, 632 Pennsylvania Ave., EVERYBODY needs and buys the ‘Business Guide.” Wells cleared $1,150 in 35 days. Send for sample. It's Free. Nichols Co., Dept. 1B, Naperville, Il. YOUR wiie cun help you run a Mail Order Business. Keep your present job, too. Write. Leon Lambert, 670-D Volutsia, Wichita, Kansas. “MOORE-MADL""— Merry-Go-Rounus. Men make money and get rich. Beautiful outfits furnished at $575 up to $2,000. Get full particulars about Merry-Go-Round business. Stamp for catalog. - ‘‘Moore-Made”’ Riding Devices, Lapeer, Michigan. ive, BE a manufacturer, Own your own business. We start you and furnish everything. Enormous profits. Steady demand. Free booklet. Men and women write today. Dept. RS, Box 691, New Orleans, La. $120 starts proiitable mail order agency business; no soliciuing; can make 0 weekly; part time required; everything supplied; bank references furnished; free sample and book. Méervel Co., 6002 Market, Phila- delphia, Pa. I MADE $100,000 As Real Estate Specialist. Free information tells how. American Business Builders, Dept. A-349, 1133 Broadway, New York. MANUFACTURE $1.00 for original $50.00 formula. Wilmerding, Penna. PATENT applications filed guarding priority, $20; drawing; deferred, $15; caveat advantages; basic protec- tion. Inventors’ Service, 11 Broadway, N. Y. WHY work for someone? Start a business; $100 Sufficient. Information, Dept. R, Paul Kaye, 149 B'way, N. your own Beauty Clay. Send Valley Laboratories, eee 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, 256 Fourth Avenue, New York. More Money Making Opportunities on pages 6 to 20

Page 19

ex- Lain, ness, 1uc, is to bora- iulas, rofit- eting irnish tional ginia. rd in- nefits, Ave., lide.” It's siness. nbert, make t $575 Round Riding . we profits. write 3s; no juired; - free Phila- Free lilders, —" Send itories, — r, $20; protet- $100 B'way, — of the ontains presting ‘an Use o know, Popular —— ties —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 instruments given. Also big new book. No obligation. S. & H. ENGINEERING COMPANY Affiliated with the Lincoln Institute of Technology 1422 W. Monroe St. Dept L-16 Chicago, Ill. Just Out 13th Edition A NEW AND GREATER Dyke’s Automobile Encyclopedia Entirely Rewritten, Rearranged and Illustrated. ~ Greatly Enlarged; 1238 Pages, 4143 Illustrations. A Practical Book for Everybody The Repairman will find this book a ready reference and guide. The Auto Owner will know how to diagnose troubles and know when repairs are done right. The Student learns the fundamental prin- ciples, the key to a successful repairman, This Book Will Teach You to Become An Expert Automo- bile Repairman, not only on testing, ad- justing and repair- ing engines, carbu- retors, clutches, rear axles, differentials, tires, etc., but an Electrical Expert on ignition, gen- erators, starting mo- tors, storage batter- ies, etc. Diagnosing any trouble will be easy. Don't wait—Order Now! Cloth $6.00—Limp American Morocco $7.50 Post paid Popular Science Monthly 250 Fourth Ave., New York City 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. POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York, N. Y. POPULAR SCIENCE MONTHLY FREE Trial Lesson This lesson in Drafting is sent free upon request. Learn from it how well qualified you are for this profession. See also how Chicago Tech. gives expert training by mail. rollment and payment of fees in ad- vance, Chicago Tech. sends this lesson first. Just mail the coupon. everywhere are searching for men who have the training to handle the important problems which must be worked out prac- tically and accurately—and the men who can do this work can name their own salaries. Don’t put off a day—start now to get this Chicago Tech. training which gives you the short cut to a larger income. Get Practical Men Back of You Chicago Tech. experts teach you the prac- tical methods which enable you to take a job knowing just what to do and how to do it. No time put in on mere theories. Every les- son deals with actual prob- Income 300% lems and you have the greater than be- direct, personal instruction fore I enrolled. of these experts at every R. L. Cary. step. All this you get by mail in your spare time. Chicago Tech. Men Salary increased 75% since taking the course. T. E. Anderson. Successful in own business as result of Chicago Tech. . Training. Always in Demand O. L. Rosin. Everywhere you find Chicago Tech, men in important posi- tions, drawing high salaries, because they have the prac- 7. To Employers: tical knowledge that makes “hs : en them worth money to rail- Chicago Keg White roads, manufacturers, engi- are practical. rit€ neers, architects, contractors, to us when you need electrical works and other Draftsmen. great industries. Train at Home in Spare Time Use hours that you now have idle to get in training that will double your income. By utilizing a little of your spare time under the direction of the Chicago Tech, experts, you can become a master Draftsman— While other schools require en-} YOU Can command a high salary and hold an important position, No need to stay in a “‘blind alley” job, no need to wait years for real success when you can so easily acquire a profession which will put you among the men for whom great opportunities are always open. You Can Double Your Earnings There are not enough really able Draftsmen to supply the demand. Great industries FREE DRAWING OUTFIT Enrolled in the Chicago Tech. Home’ Study Drafting Course you get this complete Drawing Outfit free (retail price $25) or you are given a credit on fees if you have an , tN f outfit oY Get the Free Trial Lesson and information about the Chicago Tech. Method of teaching Drafting by mail. Find out about the opportunities that Drafting offers to you. Mail the coupon today. eS weet eee eee ee eee ee ee ee oe Send the Coupon CHICAGO TECHNICAL COLLEGE Dept. 931, Chicago Tech. Bldg., 118 East 26th Street, Chicago, III. Without cost or obligation on me, please send in- structive matter about opportunities in line I have marked with ‘‘X.”" ( ) Drafting. (The Big Salary Course) No experience necessary. Free Lesson sent now. ( ) Building Trade Course For men in the building lines. Write or print name plainly 25.00 in PRIZE See top of page 6 in frent of book for details U.S. RAILWAY STEADY WORK PAID VACATIONS TANTED! $1600 to $2300 Year MEN—BOYS 17 OR OVER SHOULD MAIL COUPON IMMEDIATELY eee weeweeweweewweew eee eS Py Franklin Institute, Dept. M277, Rochester, N. Y. A Sirs: Send me, without charge, (1) sample Railway Mail Clerk Examination questions; (2) tell me how to 4 get aU. S. Government job; (3) send list of places at vhich examinations will be held; (4) send copy NO LAYOFFS mf illustrated book, ‘‘How to Get Government Jobs.” BF Weve cccccccens duccctessseesaeneeaeonn oma Travel—See Your Country. Common educa- 7 tion Sufficient. Mai} Coupon Today—SURE J Address.----------------------- puna iuenaaam

Page 20

$95 an oar “Every hour I spent on my I. C. S. Course has been worth $95 to me! My position, my $5000 a year income, my home, my family’s happiness—I owe it all to my spare-time training with the International Correspondence Schools!” Every mail brings letters from some of the thousands of I. C. S. students tell- ing of promotions or increases in salary as the rewards of spare-time study. What are you doing with the hours after suppcr? Can you afford to let them slip by unimproved when you can easily make them mean so much? One hour a day spent with the I. C. S. will prepare you for the position you want in the work you like best. Yes, it will! Thousands have proved it. For 32 years, men in offices, stores, shops, factories, mines, railroads—in every line of technical and commer- cial work—have been winning promotion and in- creased salaries through the I. C. S. More than 180,000 men and women are getting ready right now with I. C. S. help for the bigger jobs ahead. Your Chance Is Here! No matter where you live, the I. C. S. will come to you. No matter what your handicaps, or how small your means, we have a plan to meet your cir- cumstances. No matter how limited your previous education, the simply written, wonderfully illus- trated I. C. S. textbooks make it easy to learn. No matter what career you choose, some one of the 800 I. C. S. Courses will surely suit your needs. When everything has been made easy for you— when one hour a day spent with the I. C. S. in the quiet of your own home will bring you a bigger income, more comforts, more pleasures, all that success means—can you let another single price- less hour of spare time go to waste? Make your start right now! This is all we ask: Without cost, without obligating yourself in any way, put it up to us to prove how we can help you. Just mark and mail this coupon. | INTERNATIONAL CORRESPONDENCE SCHOOL Box 7609-D, Scrantcn, 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 CJ Advertising Personnel Organization L) Better Letters [} Traffic Management LJ) Show Card Lettering Business Law C Stenography and Typing Banking and Banking Law CL) Business English { } Accountancy (including C.P.A,) () Civil Service [J Nicholson Cost Accounting . Railway Mail Clerk [ ] Bookkeeping Common School Subjects _] Private Secretary High School Subjects Lj Spanish () French Dlustrating TECHNICAL AND INDUSTRIAL COURSES DElectrical Engineering ry] Architect Ll Electric Lighting r] Architects’ Blue Prints Mechanical Engineer [} Contractor and Builder Mechanical Draftsman } Architectural Draftsman Machine Shop Practice r} Concrete Builder Railroad Positions r] Structural Engineer Gas Engine Operating Chemistry (0 Pharmacy L)Civil Engineer Automobile Work LjSurveying and Mapping Tj Airplane Engines Metallurgy O) Mining (] Agriculture and Poultry Steam Engineering () Badio © Mathematics

NERD scnvnnesocaccrovsccccascnesonossesecesbonsespebesssesierenecusbeeposbeeseses Persons residing in Canada should send this coupon to the International Carrespondence Schools Canadian, Limited, Montreal, Canada

POPULAR SCIENCE MONTHLY Money Making Opportunities BUSINESS OPPORTUNITIES START Mail Order Business—Practical information concerning its wonderful opportunities obtainable through The Mail Order News, America’s leading mail trade publication. Yearly subscription $3.00. Sample see. Booklet free. Mail Order News 1637 Bristol Bldg., FOR $10.00 we'll write three catchy classified order pulling advertisements that must bring you business. Rates of profitable magazines included. Mailing lists of mail order buyers, investors, agents, etc., at reasonable rates, Marrtinek Companies, Corona, N. Y. HELP WANTED ARE you old at forty? See our advertisement on page 116 of this issue. The Electro Thermal Company, 4036 Main Street, Steubenville, Ohio. SALESMEN—We pay larger commissions than any other Brush House in the country to men selling our line of sanitary twisted in wire brushes. Sanitary Wire Grip Brush Co., 15 Mercer St., New York. MONEY Polychroming, also Silvering Mirrors. Sample and particulars free. Polychrome 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. STOP Daily Grind. Your town needs plater operator. There’s money silvering mirrors, headlights, racictors, bumpers, stoves, tableware. Reliable outfits furnished. Here's help Free. Sprinkle Plater, Dept. 98, Marion, Ind. SILVERING Mirrors, French plate. Easily learned; immense profits. Plans free. 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 addresses of 388 employers in Peru, Bolivia and Argentine for $1. South America Information Bureau, Portland, Ore. STAMPS AND COINS FOREIGN Stamp Packet, sent free. Cornish Com- pany, Schenectady, N. Y. 158 GENUINE Foreign Stamps. Mexico War Issues. Venezuela, Salvador and India Service, Guatemela China, ete., only 5c. Finest approval sheets 50 to 60%. Agents Wanted. Big 72-p. Lists Free. We Buy Stamps. Established 20 years. Hussman Stamp Co., Dept. 55, St. Louis, Mo. FOREIGN Stamps on Approval. New London, Conn. ALL for 25e! 500 desirable stamps from all parts of the world; packet beautiful French Colonials; package best hinges; packet rare British Colonies and old U. 8. You can't lose. Brown, Box 315, Savannah, Ga. RARE Bergaint 24 different scarce German Pro- visionals 10c; catalog over $2. Penna. Stamp Co., Manor, Pa. 100 DIFFERENT stamps free to popular approval applicants; postage 2c, Christensen, 124 Second Street, Milwaukee, Wisconsin. FOUR unused sets, hinges, 55 different, premium 15c. Deering, Newton St., Marlboro, Mess. STAMPS—50 varieties, Africa, Brazil, Peru, Cuba, Mexico, ete., 10c. 50 different U. S. 25c. 1,000 hinges, 10c. 1,000 mixed, 40c. List free. C. Stegman, 5949 Cote Brilliante, St. Louis, Missouri. 17 VARIETIES Bulgaria stamps, 20 cents. List of 7,000 low-priced stamps free. Chambers Stamp Com- pany, 111C, Nassau Street, New York City. CALIFORNIA gold $& size, 27c; $% size, 53c. cent and catalogue, 10c. Norman Schultz, Springs, Coloraco. STAMPS free! 24 British Colonials to approval applicants. Nickles, 122 Florida, Washington, D. C OLD coins—Lirge Spring selling catalog of coins for sale, free. Catalog quoting prices paid for coins, 10c. William Hesslein, 101-B Tremont St., Boston, Mass. STAMPS, 100. All different, 3 cents. Lists free. P. §. Quaker Stamp Co., ‘Toledo, Ohio. ALL different, 300, 25c; 500, 50c.; Fred Onken, 630 79th Street, Brooklyn. RARE Coins, Medals, Paper Money. United States, Foreign and Ancient. Old Coin and New Catzslogue 10c. Alexis Mengelle, Box 387, Colorado Springs, Colo. BAVARIA, 50 varieties, 10c. Germany, 50 varieties, 7c. yeorge, 955 Seventh St., Milwaukee, Wis. 100 RARE stzmps, all different, bargain lists, Stamp Magazine, everything 7c. Stanton, Niantic, Conn.

Gilmore Stamp Co.,

White Colorado

1,000, $1.50.

FREE 25 different U. S. stamps with 60% approvals. 45 different U.S. 10c. Seidenberg, Merton, Wis. 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 9c. To introduce our Sudden Service approvals. Fennell Stamp Company, Dept. C. Fullerton Bidg., St. Louis, Mo, TEN Large Showy Stamps Free.. In ordefto intro- duce our fine List of Sets, and 50% Approvals. Postage 2c. Payn Stamp Co., 945 Vista Drive, Los Angeies, Calitf- FAMOUS Fenway Outfit—2 triangle stamps, small album, 5 blank approval sheets, 250 hinges, perforation gauge, 5 large French Colonizls, 2 speci<! deliveries, ani- mal set, red cross set, packet 55 different, including Abyssinia, Azores, Cape of Good pe, Bosnia, Crete, Congo, etc., 16-page price list, all for 12¢ to new approval applicants. Fenway Stamp Co., Fenway Station, Boston, Mass. SWITZERLAND, 30 Different, Kemper St., Wollaston, Mass. 200 MIXED Foreign 10c. 50 U.S. each different, 10°. Marie Stamp Bureau, Villa Park, Il.

15e. Browne, 90

Ae Teach COMMERCIAL

ART Meyer Both Company the largest Coskmercial Art Organization tthe World offers you a practical training, based upon twenty-five years of success, This nationally known organization each year produces and sells to advertisers over 15,000 commercial drawings. This well paid profession equally open to men and women, Home study instruction, , Get Facts Before You Enroll in Any School Ask the Advertising Manager of the leading newspapers in your city, about Meyer Both Company—let them tell you about us. Send four cents in stamps for illustrated book telling of the success of our students. MEYER BOTH COMPANY Michigan Ave. at 20th St, Dept. 35 CHICAGO, ILL. Note—To Art and Engraving Firms: Secure artists among our graduates. Write

Have a Business of Your Own Get into the Automobile Business,—the world’s Greatest Industry. Start a business in yourowntown. Thousands of opportu- nities for Trained Men, Fifteen Million Autos, Trucks and Tractors to repair; fifteen million Bat- teries to keep in service; seventy million Tires to re- pair and replace. Thousands of our Graduates Earn $2000 to $10,000 Yearly Fit yourself for a better job at bigger pay. Auto factories and service stations continually asking for our graduates, Big Auto Factories endorse our school. Detroit, the “‘Heart of the Auto Industry" is the logical place to learn the business. Get the facts. Be a winner! Have a Business of your own. Write today for illustrated catalog. MICHIGAN STATE AUTOMOBILE SCHOOL 589, Auto Bidg., Detroit (The Auto Center) 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. Price, $1.50. POPULAR SCIENCE MONTHLY 250 Fourth Avenue $f NEW YORK

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 original drawing easy to learn. Send 6c in stamps for fullinformation and chart to test your ability. Alsostateage. THE LANDON SCHOOL 1451 National Bidg., Cleveland, GC.

~, ~ QQ

Here’s th kest way to b’ f your any thane fora bane 3. Robinson jamoge from $20 boss Auto J work. Takes only an hour s day ° m $20 to $100 a week in six months, You, too, can . Lilshow you how. Learn at e. Learn by *‘Job-Way”’ Plan. Send for big illustrated book, explaining ‘‘Job-Way’’ course, Tells about guarantee, free tools offer. Low price a. No obligation. A postal willdo. Write NOW. J. R. BAYSTON, Pres., CHICAGO AUTOMOTIVE INSTITUTE Dept.

STAMPS, 105 China, etc., 2c. Album (500 illustrations) 3c. Bullard, Station AA, Boston. 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, 259 Fourth Avenue, New York More Money Making Opportunities on pages 6 to 18

1786 536 South Clark Street, Chicago, Illinois Attend a School Operated by Build- Be ing Contractors. Three Months Day Course $75.00. ASSOCIATED BUILDING EMPLOYERS 1280 A. B. E. Building, Grand Rapids, Mich. Bricklayer!

Page 21

st he ig, ch er ell nd | ing yer tell ortu- utos, Bat- to re- rly tories uates, , the learn siness OOL nter) —_——— ) |*STAMMERING! $100 a Week in this Fascinating Business ARN big money asa cartoonist! Millions of dol- lars were spent last year on comic strips, po- litical and sport cartoons, ani- mated cartoons, etc. Thousands of new cartoon- ists are needed now to meet the ever-increasing demand for this work. Never before have the opportunities in this fast-growing field been so many, so varied or so high-paying. Easy to Learn CARTOONING at Home in Spare Time Regardless of how little you know about car- tooning now, you can easily qualify for a po- sition in this attractive, high-salaried business. This home-study method starts you at the simplest fundamental principles of cartoon- making and takes you through every branch of humorous and serious cartooning. You will be amazed at how quickly it teaches you to draw salable work. Many students of this method began to sell their drawings before they were half through their courses. The training paid for itself long before they finished it. Learn cartooning this easy way. Enjoy the fascinating life of a successful cartoonist—easy hours, freedom from routine, your own boss, and $3,000 to $15,000 a year for this work that is play! Send for FREE BOOK Learn more about the wonderful opportunities in Cartooning, and details : about this remarkable P= home-study method. A handsomely illustrated booklet has just been prepared which, upon request, will be sent to you without the slight. est obligation. Thig booklet gives a thor- ough outline of the car- tooning field, and exe plains in detail this wonderful new method of teaching Cartoon- ing. Send for it today! Room 249, 1113-15th St., N. W., Washington, D. C. WASHINGTON SCHOOL OF CARTOONING Room 249, 1113-15th St., N.W., Washington, D. C. Please send me, without obligation, your Free Booklet on Cartooning and full details of your home-study method of teaching Cartooning. Name LEARN ENGINEERING Great Demand for Practical-Technical Engineers: Big Salaries, Wonderful Opportunities. Thousands of our Fraduates: holding responsible high-salaried positions. ractical-Technical Courses from 3 Months to 2 Years in Elec trical and Mechanical Engineering. Simple and Con- [ere Method. Faculty of Trained Experts. New uilding. Extensively Equipped Laboratories and Shops. Department of Architecture. Structural and Mechanical Drafting. Degrees Awarded. Positions Secured. Day and Night Sessions. 22nd Year Pegins Sept. 17. Write for Catalog A FINLAY ENGINEERING COLLEGE, Kansas City, Mo. POPULAR SCIENCE MONTHLY 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 mysteri- Ous intruder? Who could tell? Yet Berteau identified the man without hesitation and won the $2500 reward. How did he do it? Easy enough for the Finger Print Expert. He is the specialist, the leader, the cream of de- tectives. Every day’s paper tells their wonderful exploits in solving mysteri- ous 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 upon finger print evidence — and big rewards go to the expert. Many experts earn regularly q rom $3,000 to $10,000 per year. / $2,500 Reward For the Capture of An Unknown Man Learn at Home in Spare Time And now eo 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 Outfit, 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 exp! wonderful training in detail. Don’t wait until this offer has expired — mail the coupon now. You may never see this an- nouncement again! You assume no obliga- tion—you have everything to gain andnothing to lose. Write at once — address UNIVERSITY of APPLIED SCIENCE Dept. 13-66 1920 Sunnyside Ave., Chicago University of Applied Science, Dept. 13-66 1920 Sumeuiie Avenue, Chicago, Illinois Gentlemen: Without any obligation whatever send me our new, fully illustrated, FREE book on Finger Prints and your offer of a FREE course in Secret Service Intelligence and the Free Professional Finger Print Outfit, Name -— Address What Shalll Be? DECIDE THIS QUESTION ONCE FOR ALL! Our expert vocational counselors, employing latest scientific method which eliminates a!l guess work, will show you what occupation you are best fitted for, and guide you step by step until you succeed. : Write for free information today. Bureau of Vocational Research, £96-B Broadway, New York rt JIRA QAR Learn at home to monnt birds, ani- me roves. Eomolete lessons. Easily and quickly learned by men, hovs an en Write for Free Taxidermy Book. Tells all aman a ery rtsman, trapper an Nature lover should know this wonderfu fascinating art. Save your troohies. Big profits. guaranteed. 75,000 grai- 9. Investigate, Write for Free Book. Northwestern School of Taxidermy 1786 Elwood Bldg... Omaha, Neb Ifs G@use and Gire % You can be quickl y cured. Send 10 cents for 288 pase qoth bound book on Stammering and Stutter- mm s t tells how I cured myself after Stammering 3509 Euttering for 20 years. ENJAMIN N. BOGUE, ogue Building, 1147 N. fil. St., indianapolis. aa ; ; l Method in 60 i days—no experience needed. We establish you in your own shop, 4 Si any locali y, worth $60 weekly, up; furnish all material and plan to secure orders 5 . f-on local merchant: t» d> right at h me, evenings, if desired. Get into this tascinat ng, easily Ow al Ss learned, profitable business. Cost low—terms easv. Illustrated matter and terms FREE. , EMPIRE INSTITUTE, 1476 Broadway, New York

Page 22

POPULAR SCIENCE MONTHLY

Radiotrons WD-il 2n/WD-12 | CMade History! It isn’t a genuine WD-11 unless it’s a Radiotron. It isn’t a genuine WD-12 unless it’s a Radiotron. Itisn’t a genuine UV-199 unless it’s a Radiotron. It isn’t a genuine UV-200 unless it’s a Radiotron. Itisn’t agenuineUV-201- Radiotron eh This symbol of quality is your protece These are dry cell tubes—the tubes that made possible the swift progress of radio in the home everywhere. They meant clear tone—undistorted detec- tion—radio and audio amplifi- cation—and volume reproduc- tion — all with dry batteries. They meant radio in the city— on the farm—off in camp— everywhere! And to-day, there are millions of these popular Radiotrons in use. Today everybody knows them familiarly as “WD-11’s” and “WD-12’s.” But they are not genuine unless they are RADIOTRONS. Always: be sure to look for that mark on the base, and for the RCA mark on the glass. It’s important, whether you are buying a new set with the Radiotrons in it, or buying new Radiotrons to replace old ones. Always look for the Radiotron mark and the RCA mark. Then you have the gen- uine — sure to live longest — serve best. Radio Corporation of America Sales Offices: Dept. 119 ~ 233 Broadway, NewYork " 10 So. LaSalle St., Chicago, Ill, 433 California St., San Francisco, Cal. REG. U.S. PAT.* OFF.

Page 23

By Prof. Sampson K. Barrett Engineer in charge of battery testing Popular Science Institute of Standards ROBABLY no piece of radio equip- P ment has its vital parts more com- pletely hidden than a storage bat- tery. In looks, there is no appreciable difference between a 10- and a five-dollar battery. The difference is in the plates, and there is but a small hole through which to examine them. The engineers of the Popular Science Institute of Stan- dards examine these plates by observing the functioning of a battery during charging and discharging. Three things must be investigated to determine the value of a battery—the ampere-hour rating; the life in cycles; the ability to retain a charge. After a thorough inspection, the specific gravity of the electrolyte in the cells is measured. Presumably, when bought, a battery should be in a state of charge. It must be remembered that all manu- facturers do not charge their batteries with an electrolyte of the same specific gravity. Many batteries are completely charged when the hydrometer reads 1.200; others run as high as 1.300. In general, one will find batteries completely charged at 1.275. Our engineers compare the figures obtained on this specific gravity test with the claims of the manu- facturer to determine the state of charge from which to start the test. Then the battery is discharged by utilizing load rheostats until it reads 514 volts—for a six-volt battery. The specific POPULAR SCIENCE MONTHLY Testing Radio Storage Batteries gravity is read and that becomes the lower discharge limit. The battery is again charged and readings are taken at intervals to determine the number of ampere hours required to return the battery to its maximum charged con- dition. When the voltage ceases to rise, the battery is considered charged and specific gravity is again measured. This determines the upper range of specific gravity for this type of battery and that is compared with the manufacturer’s claim. Once more the battery is discharged and the ratio of ampere hours taken out © POPULAR SCIENCE Monthly Guarantee 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. 23 Professor Barrett is shown hooking up the automatic re- cording voltmeter preparatory to charg- ing a storage battery. The chart on the left shows the voltage change in 24 hours of the battery to those previously put in when the battery was charged gives its efficiency, which should range from 85 to 95 per cent. Batteries increase in efficiency for the first few cycles, usually arriving at the maximum at the seventh cycle. If a radio battery is less than 80 per cent efficient at the fiftieth cycle, the Institute of Standards disapproves it. Probably the thing that interests radio fans most in a storage battery is its ability to retain a charge. After the above tests, the battery is charged and allowed to stand idle, being tested every few days. The minimum requirement is that a battery shall not exceed two per cent of self-discharge every day. A good battery will still show 80 per cent of its initial capacity after three months. It is obvious that a battery standing up under the severe tests detailed above must give satisfaction. A purchaser will do well to use batteries approved by the Institute of Standards. It is obviously impractical for even as completely organized a bureau as the Institute of Standards to test all products listed in tool or radio catalogues adver- tised in our columns. Only tool and radio products specifically advertised in POPULAR SCIENCE MONTHLY are tested and approved by the Institute. 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 Institute.

Page 24

ee a Ga ———— a — TRADE MARK REG. U.S. PAT. OFF. HEN the archer misses the center of the target he seeks for the cause of his failure within himself.” —Confucius The man who ownsa Grebe Receiver seldom misses, for theTangent Wheel Vernier enables him to acquire ex- treme accuracy in tuning. Peder Mu Grebe Regenerative Receivers are licensed under Armstrong UV. S. Pat. No. 1,113,149, Oct. 6, 1914. POPULAR SCIENCE MONTHLY Device found only REB Kecerve rs am stance 5 ‘ NV for. _“Hair’s breadth” Dial adjustments The Grebe Tangent Wheel Vernier ‘Te HAVE once experienced the ease with which you can tune in stations on a Grebe Receiver, is to know the value of the Tangent Wheel Vernier. The keenest appreciation comes, however, when you find yourself instinctively reaching for this ingenious little device below each of the tuning dials on some neighbor’s receiver. This and many other details of Grebe crafts- manship are fully covered by patents granted and pending. These details are sought by the man who looks inside of the cabinet. Let us tell you more about Grebe Receivers A.H. GREBE & CO., INC. Van Wyck Blvd. - Richmond Hill, N.Y. Western Branch: 451 E. 3rd St., Los Angeles, Cal. UNS Gaacs 28 eta ee Oe, eee a

Page 25

POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor September, 1924 UPPOSE our earth, instead of being governed by the sun, were a planet of a giant exploding star that, in _ occasional eruptions, threw out 20 umes as much heat as the sun. What would happen to us? I have drawn here an imaginative Picture of how our world might appear under such conditions. It was suggested d a recent mysterious revival in the Tightness of the great dying red star ff Drawn for Popular Science Monthly by Scriven Bolton, F.R.A.S. If the Exploding Mira Ceti Were Our Sun By Scriven Bolton, F.R.A.S. Mira Ceti, in the constellation Whale. One explanation of this brightness is that a crust is beginning to form on the surface of the star as it cools. Pressure becomes so great that violent explosions fre- quently occur, and the light and heat emitted is increased many times. Mira Ceti is dying down rapidly, and now is not as hot as the sun. Yet it is so vastly superior in size that if we were as near to it as we are to the sun, our globe would be a red-hot, lifeless mass, without atmosphere or oceans. The heat emitted by the star after every explosion would approximate 1000° F. at the earth’s surface. Metals with com- paratively low melting points, such as tin, lead, and bronze, would flow like water. The terrible bombardment of poisonous gases would make life impossible. Mira Ceti is a star of the older type. It appears to have a gaseo-liquid interior; not wholly gaseous, as the younger suns. The spectroscope tells us that its atmo- spheric layers are composed chiefly of hydrogen and titanium oxide. 25

Page 26

POPULAR SCIENCE MONTHLY

Sky Sports of Tomorrow By Lieut.-Comm. Fitzhugh Green, U.S.N. THLETIC contests and other forms A of sport are being literally crowded off the earth. Last year 303,430 people attended the World’s Series. Football stadiums holding 100,000 spectators are being built in vari- ous parts of the coun- try. Larger swimming beaches, larger gym- nasiums, more numer- ous golf links and ten- nis courts are being put into commission as rap- idly as money and labor are available. But the crowding always seems to be just ahead of the building. It is practically impos- sible to attend a mod- ern contest that has been widely advertised without a disagreeable Bubble- preliminary battle for — 4 TEE eee ’ one of the parking space and Ot thrilling of the tickets. earliest air sports A fascinating solu- tion of this vital national problem is sug- gested by the sudden entrance of aero- nautics this year into the field of safe and sane sports and pastimes. This development is coming from two directions: first, the ‘““baby balloon” used as a sort of life-preserver to carry its wearer into the free and uncrowded sky; and second, the commercial dirigible re- duced to taxi size for family use. Both types have been studied at our naval air base at Lakehurst, N. J., and at Mitchel Field, L. I., of the United States Army. The first signs of this novel outgrowth from military aviation came in the form of “‘dog-fighting,’’ ‘“‘bubble-chasing,”’ and “aerial tag.”’ A “dog fight’? with planes was simply a mock duel between two high- speed combat machines thrillingly man- euvered by stunt fliers. Lieutenant A. L. Williams, the navy pilot, who won the Pulitzer Prize last year with a speed of 266 miles an hour, probably is the world’s best “‘sky terrier.”” ‘‘Aerial tag’’ is another form of this pursuit game, and is played according to special rules that determine when each pilot shall be the pursuer or the pursued. “Bubble chasing” is still another spec-

A number of tacular game with planes. small free balloons of various colors are released. Each pilot in the air chases his own color, seeking to destroy the drifting bright-hued rubber bubbles by diving into them with his whirring propeller blades. F COURSE such performances are replete with thrills. They represent the most blood-chilling form of aerial acrobatics. The men engaged in them risk their lives every moment of the game. But, to the surprise of the authorities, the popularity of all these aerial demon- strations seemed to center not on the dan- gers that beset the intrepid birdmen, but upon the spirit of competition involved. Acting on this cue, our experts at once began developing an entirely new tech- nique. Projected into the future, the novel forms of flying they have achieved may revolutionize our modern ideas of sports and athletic contests. Each pilot seeks to destroy small bal- loons of his chosen color by diving into them with the plane For instance, it was soon seen that both in dog fights and in bubble chases a crowd would be even more enthusiastic if slow planes were used rather than racers driven by notorious speed demons. Skill and agility in air maneuvers proved, in the long run, more alluring to human interest than hair - raising stunts, which soon palled after the first excitement had worn off. As a result, the percentage of acci- dents in such entertain- ments soon was reduced to almost zero. ROM this form of j aerial sport the next step was a logical one. When it was seen that people wanted compe- tition between the en- tries, combined with safety of the entrants, ‘parachute racing” was

The shaded areas indicate the most impor- tant helium deposits in the United States the world’s greatest producer of this wafetv gas for airships The straight lines indicate less im- portant deposits. The map was made for this magazine by R.B. Moore, D.Sc., for- mer chief chemist, U. S. Bureau of Mines

Beyond devised sent up Ata giv

am th of the of his ] danger< save in proachi paracht meteor » rents o By hav tive su ances ¢ were jo But © withar § it lacks based « this su brough As vy of aju that of the sw add ri swimr that tl ody | volum The

spher Sas c¢ is pa | non-f “swir

Page 27

POPULAR SCIENCE MONTHLY devised. Several parachute jumpers were sent up in slow planes or captive balloons. At a given signal all dropped at once. F COURSE, in this form of contest the speed of falling is beyond control th of the jumper unless he is given control wd of his parachute’s apex vent. But this OW dangerous expedient is rarely resorted to ET's save in an emergency, such as when ap- cil proaching open water. So the result of a he parachute race is left to the caprice of local ng meteorological conditions. Vertical cur- an rents of air are the determining factors. ts, By having colored parachutes or distinc- ter tive suits for the airmen, their perform- ad ances can be wagered upon just as if they It, were jockeys. ci- But the parachute game hasn’t met in- with any wide enthusiasm, chiefly because ed it lacks the element of human competition based on man’s individual effort. Hence, this summer the ‘‘jumping balloon” was Beyond the great crowd of spectators, is the giant navy dirigible Shenandoah at her mooring-mast. of brought into favor. xt As was suggested above, the principle 1e. of a jumping or baby balloon is similar to ni at that of a life-preserver. But with air as \ e= the swimming medium it is necessary to \ n= add relatively more buoyancy to the My th swimmer than in water. The reason is i ts, that the weight of air displaced by one’s & as body is far less than that of the same “a volume of water. a The jumping balloon is just a small 4 A balloon jump over \ gg gp peng : e } eee 8S BS tO Taking off with a jumping balloon for a 7 oo ar or “wim” through the Sa a wae balloon ) running broad jump is strapped comfortably to the jumper’s back aK es cite _ the back with broad ») a 1 : bands running under ) the armpits and chest. It is necessary, of course, that a negative to buoyancy always =e exists or the jumper is " ( Some in danger of helplessly ) RE pent a Lemire) leaving terra firma for a 7 25 FT. SIN: haphazard ride of un- sphere containing helium or some other Sas considerably lighter than air. Helium ‘S particularly convenient because it is 10n-flammable, and so permits the Piesaicogall to smoke if he or she desires. ‘he balloon is strapped comfortably on known distance in the air. But with only a few ounces of negative buoyancy a man can perform astonishing feats. Take the athlete who can jump, say, 24 feet. By reducing his weight 1000 times or so, theoretically he could jump At right is a jumping balloon about half a mile! Asa matter of reality, though, he would find that the awkward size of his ‘“‘air preserver” would prevent his getting any sort of take-off. Yet one of the navy gang at Lakehurst has vowed that before he leaves the station he will, by this means, jump over the huge hangar of the dirigible Shenandoah, which is 348 feet wide and 200 feet high! It is at this point that we enter the broad realm of future air sports. For if one’s body can be made as light as a feather, one may jump and swim and float in the air as we now do in the sea. Certainly there is need for something of the sort. Take conditions at Coney Island. Of course that resort is near a big city and is more crowded than most beaches. But many others will soon be as congested. Not so long ago a man who was toppled over by a big wave knocked two teeth out by striking a. stranger’s knee on one side of him, while his flying heel delivered a French Kayo to an un- suspecting lady on the other. Obviously, there simply wasn’t room to swim. Whereas had the same Sunday multitude been cavorting above the ocean at that point, there would have been comfortable space for a thousand times the same number of holidayites. “ AIR beaches” soon will be a reality. The skies above large city parks would provide areas. Of course, “‘life lines’? will have to be strung. On an ocean beach there are buoyed ropes. On an air beach there will be light nets dan- gling from captive balloons so that the air swimmer will not be blown adrift across the city. The expense will not be very great. Balloons will be hired, fitted, and worn as roller skates or bathing-suits are now. And, best of all, no risks will be taken. The balloon will be locked on by an attendant so that the wearer cannot escape even if he should try. Another form of air sport is rapidly evolving from the taxi style of dirigible. The French recently have designed and built what they call the “Vedette.”’ This is an airship that has the same relation to big fellows like the ZR-1 as a trim road- ster has to a bulky truck. (Continued on page 125)

Page 28

POPULAR SCIENCE MONTHLY Mr. Gardner in his laboratory, where every kind of paint and varnish is subjected to the severest scientific tests What Paint Means in Your Life ‘An interview with Henry A. Gardner, Director of the Institute of Paint and Varnish Research at Washington HILE touring New England re- cently I came upon a tumble- down barn, its roof hollow and broken, siding ragged, and its mighty beams awry and crumbling. Neighbors testified that it had never seen paint. Just beyond was a barn a hundred years older that still stood square and unbroken. It had outlived successive owners, and the secret of its longevity was simply paint and more paint. But the secret of paint is an- other story. In fact, paint has innumerable secrets, many still unlocked. Within the last decade or two, scientists have been searching chemistry for the keys to paint mysteries, and have opened the doors into paint and varnish knowledge that previously were quite unsuspected. The scope of the preservative art has been extended in a_ hundred directions. In the days when those New England barns were built, paint was just paint. Its alchemy lay deeply concealed under a burden of ig- norance. Today the paint put on a barn would not be used on the deck of aship; and the paint on the deck would be of no value on the ship’s bottom. Nor would the paint on the ship’s bottom be of use in painting an acid-manufacturing plant. We might go on with these comparisons, and only touch the high lights of paint research. Indeed, research has thrown the search- light into tunnels of paint usage hitherto undreamed of. It was never known, for instance, that paint might have a pro- nounced effect on acoustics, human growth, and plant life. Nor was it real- ized that the color of paint could affect materially the radiation from a steam- heating plant or the evaporation from a tank of naphtha or gasoline. By Edward Mott Woolley’ Ever since large chemical factories came into existence, the bane of the adjacent house-owner has been the discoloration of the paint on his home —for which there seemed no remedy. Retarding the work of fire, brand- ing cattle, disinfecting, fighting off the barnacle and toredo in salt water —these now are the duties of paint. Paint research has set in motion new industries that concern not only pig- ments and chemicals, but horticul- tural activities as well. To get the essence of the progress I went to Washington and talked with Henry A. Gardner at the Insti- tute of Paint and Varnish Research, which for years has been the focus of appeals by the paint and color industry regarding the secrets of preserving wood, metal, cement stone, and other materials. For 15 years Mr. Gardner has been the genius of the paint industry, which stands back of this research organization. I found, near the War Department, a paint laboratory of extensive ramifica- tions. There were optical and other physical instruments and devices highly scientific, a minia- ture paint, color, and_ varnish factory, and numerous rooms filled with chemical paraphernalia With the pneumatic sprayer one man now can do the work of five using the hand brush. Below: Tests showing effects of toredo on wood uncoated and coated with experimental paints and submerged six months in ocean. Unpainted planks are badly pitted ly 52 he Ad * ‘ iM. rae * hd —such spectrt There physio colors, metho paint 1 “ FO wa activit and br and il colors, the sci produc nishes The p: workir but o physic for all lems c “In Gardn made | use of pigme! helpin; paints, den fre velopn by th metal paint | “WI has 1 used |] ceive | and tl to dev “Pi paint practi: facturi factory nically tories | the p from a year “In for an “peop Cities turnir was d

Page 29

; of try od, als, the ind, aint icae and and nia- nish oms alia an the ing ted nts

—such as colorimeters, refractometers, spectrophotometers, and viscometers. There were rabbits and guinea pigs for physiological and psychological tests of colors, and no end of mechanisms and methods for testing the performance of paint materials. ‘I FOUND, however, that the laboratory was merely the pivot on whichrevolved activities extending over the continent and beyond—on the land, underground, and in the water. Few consumers of colors, paints, and varnishes know what the scientists are doing to improve these products and to find new paints and var- nishes for checking the ravages of nature. The paint scientist must have at least a working knowledge, not only of chemistry put of bacteriology, biology, botany, physics, pathology, and other sciences, for all these have been applied to prob- lems confronting the industry. “In recent years especially,” said Mr. Gardner, ‘“‘the paint chemist has POPULAR SCIENCE MONTHLY

Testing the endurance of various kinds of paint on concrete surfaces. Similar tests have been made on cloth, steel, wood, and other

made many discoveries to extend the { use of preservative coatings. New pigments and colors are now in use, helping to meet the demand for paints, thus taking some of the bur- den from white lead. That these de- velopments are necessary is indicated by the fact that demands on the metal lead may make the supply for paint insufficient. “Whenever a need for a new paint has manifested itself, the chemist used his imagination, first to con- ceive the possibility of such a paint, and then through scientific research to develop it. “Fifteen years ago scarcely a dozen paint factories had chemists. Now practically all of our 300-odd manu- facturing plants use them. One factory alone has more than 80 tech- nically trained men in the labora- tories and plant. In the last 10 years

” {oes

In light colored cages animals grow rapidly, while dark paint retards them. Note how this rabbit is attracted to the light spot

Radiators painted white give 20 per cent more radiation than unpainted ones. Other colors in order of their radiation values are cream, red, green, yellow, black, aluminum, and brown the paint industry has grown in value from $200,000,000 to over $400,000,000 a year, “In the days when any paint was used for any surface,’ Mr. Gardner continued, People who lived in factory or mining cities found the paint on their houses turning black from chemical fumes. It Was discouraging to paint anything white,

and even light colors soon became streaked and sooty. ‘‘House-owners were in despair. But meanwhile research went on, and today we have paints that remain unchanged in atmospheres of hydrogen sulphide and similar gases. One of these paints is made from a white pigment now produced from titanium ores, a large quantity of which is

materials in different parts of the country to determine the proper paint to use under varying climatic and wearing conditions found on the sands of the Florida beaches. Tests made on houses where an abnor- mally high percentage of hydrogen sul- phide is present have shown very white surfaces and great durability for several years. < NOTHER development that has brought about an entirely new vogue in interior decoration in houses and factories is the large-scale production of lithopone, one of the newer white pig- ments. In 1907 lithopone was being in- troduced gradually to the paint trade. Combined with Chinese wood oil var- nishes, manufacturers were able to place on the market coatings of great hiding power and extreme whiteness. This marked the beginning of a nation-wide fashion for painted walls, and today it is the custom in hospitals, hotels, apartment houses, and many public buildings to use paint upon wall and ceiling surfaces. In factories the amount of electric current saved through the use of modern, sani- tary, light reflecting paints has more than balanced the cost of the paints and their application. Over 100,000 tons of litho- pone is now used annually ir. the United States. “Another white pigment that the paint- grinder could not do without is zine oxide —the whitest pigment produced. Its use in interior enamels and as a component of exterior paints are its chief applications. “The development of paints for acid- manufacturing plants, packing-houses, iron beams of smelters, pipe lines, under- ground timbers in mines, and similar structures all form stories of interest. The necessity for special paints has thus built up the ready-mixed paint industry. Hundreds of tests are made before the formulas for these paints are finally adopted.”’ Recent accomplishments in the paint- ing of metal, especially adaptable to the automobile, were explained by Mr, Gardner: “The automobile industry has been largely dependent on vegetable oils for desirable coatings, but now, through an adaptation of guncotton, a new type coat- ing has been developed in the industry. It will not replace the old high gloss var- nish finish, but will be used indefinitely for special purposes. We grow the bulk

Page 30

39 of the world’s cotton and we get nitric acid from the air—the two products re- quired for the production of nitro- cellulose, the base of this coating. Pre- vious to prohibition we produced fusel oil, from which a solvent for nitro-cellu- lose is made. Now there is produced in America a solvent known as butyl ace- tate, used widely in these new finishes. For coating wood it has not reached its ultimate development. “| EVERTING to metal paint in gen- eral, extensive experiments have been made to discover formulas to best protect iron and steel. In different sec- tions of the United States we have set up series of painted metal panels for long periods. Many of these were exposed on Young’s Million Dollar-Pier in Atlantic tung tree in bloom. seedlings. City. The application of principles thus learned, means an annual protection from rust of several million dollars. “Field tests have also been made with steel fence wire, cement structures, shingle roofs, and metal and wood roofs in vary- ing climatic conditions.” My conversation with Mr. Gardner turned to the scarcity of drying oils and the growing demand for them. And here he told me about a wholly new industry, which paint research has brought to America. “EN RECENT years,” he said, ‘“‘Chinese wood oil or tung oil has been most im- portant as the basis of practically all waterproof varnishes. During the last two years the price, normally about one dollar a gallon, rose to over four dollars, and even at that most of the oil was adulterated. “The Department of Agriculture, how- 7 5 e = ever, had brought over a iew of the tung + +h ce « +7 » “parFe aan ana lan nuts about 12 years ago, and planted sm a fare 314} ma. T a them in a few Southern States. I visited these places on several oceasions during Among them were 10 trees planted at the University of Florida, on the grounds of the State Agricultural College at Gainesville miles southwest of These trees are fully as vigorous as any in China. ‘he growing of sufficient trees to produce the oil for America was then brought to the attention of the Educational Bureau of the Paint and Varnish Manufacturers’ Associations. the last few years. e some d0 Jacksonville. As At a recent convention a Large acreages have been cleared for tung These promise to rival the grapefruit and orange trees POPULAR SCIENCE MONTHLY Blossoms of the tung tree, now grown in Florida for the oil in its nuts. This oil is the basis of many waterproof varnishes fund was sub- scribed to start an American tung -oil indus- try. ‘Fortunately, the year before a large quantity of nuts from Flor- ida had been planted in a small nursery, and over 100,000 seedlings were produced. During the last three months we have cleared large acreages in northern Florida and planted over 25,000 young seedlings, and something like 25,000 seedlings in individual small tracts adja- cent to Gainesville. In this work the Department of Agriculture and the Uni- versity of Florida have given full co- Breaking up the tung nuts in a machine preparatory to ex- tracting oil for var- nish from their meat operation to members of this Institute. “This is of great interest to northern Florida agriculturists, as frost played havoc with citrus fruits there. Peanuts and cotton largely constitute the agricul- tural pursuits in that region, and do not average over $20 yield an acre. It would appear that the tung-nut tree, properly cultivated, will be the salvation of northern Florida, and that within a few years there may be sufficient groves planted to meet fully the requirements of the American varnish industry. The ojj from the Florida nuts is superior to that from China. We have a large nursery at Gainesville, where we are growing sced- lings for dissemination to agriculturists throughout the northern part of the State, “In a similar way our Educational Bureau has inaugurated much work in the Northern States, where flax is raised for linseed oil. The study of flax diseases, soil conditions, methods of planting and harvesting, crop rotation, and so on, have been carried on in a scientific manner, In all this work the State Colleges of Agriculture in North and South Dakota have cooperated. “a oF industry is always on the watch for newer paint oils and resins, ard far parts of the world have been scoured, We have investigated the ojls from many species of nut-bearing trees and _ seed plants in Japan, China, the Philippines, Australia, Mexico, and other foreign countries; the oils from the waste raisi seed of California, from the soya bean— now grown quite widely in America— from the chia plant of the Southwest, from a dozen different sea animals, and from other sources. Many of these have good drying properties and are applied to a limited extent.” The story of varnish is quite as interest- ing in many respects as that of paint. Continued research has built up almost unbelievable qualities in varnish coatings. “‘Few consumers have any notion of the grueling trials that modern, high-grade varnish must withstand,’? Mr. Gardner explained. ‘Some of the tests for stan- dardized water-resisting spar varnish are these: The dried film must survive im- mersion in cold water for 18 hours and in boiling water for 15 minutes without whitening or dulling. It must show ro dulling, crow’s-fcoting or frosting after five hours’ exposure to gas drafts. After baking in an oven at about 100° C. for five hours it must show no cracking when bent. It must have a definite tensile strength and elongation.” An outstanding development in the le paint industry was the coming of the spray machine, which completely uP rooted traditional methods of painting 12 factories. In automobile plants espe cially, spraying has almost superseded the hand brush. (Continued on page 126) 66 beard, \ takable platfort Buildin John F this m tinguis] enginee tuted ii of the ing mil it bear ents h such m Lord Willi: Westin ander» Marco ble, El and O: HI is Swase’ his moven hearin round voice, that passin dle life 60, pe matte in his : year, born N.H. He world builde friend ter R. ner & most giant noted tion | mark omy | Galil ing te have fruit with wrot have Nc teles ufact has ¢ chin fact It has his |

Page 31

rly few Veg S of oil that V at ped. ‘ists ate, onal < in ised ses, and lave ner, $ of cota atch ard red, any seed neg, elgn isin n— rest, and lave lied "est- Lint, nost ngs. the rade dner tan- are im- d in 10ut 7 no ifter fter for shen asile the

POPULAR SCIENCE MONTHLY

31 “Do It Right if It Takes a Year” The Story of How Ambrose Swasey Made Possible Some of the Wonders of Modern Astronomy By George Appel FEW weeks ago a short, broad- A shouldered, active man with snow- white hair and pointed white beard, whose personality suggested unmis- takable evidence of eminence, stood on a platform in the Engineering Societies Building in New York City to receive the John Fritz Gold Medal. The award of this medal is probably the most dis- tinguished honor that can be paid to an engineer, for since the medal was insti- tuted in 1902 and presented to the father of the modern roll- ing mill whose name it bears, its recipi- ents have included such men as Edison, Lord Kelvin, Sir William White, Westinghouse, Alex- ander Graham Bell, Marconi, Alfred No- ble, Elihu Thomson and Orville Wright. HIS man’s name is Ambrose Swasey. Observing his brisk, alert movements, and hearing the full, rounded tones of his voice, one would say that he was just passing beyond mid- dle life—that he was 60, possibly. As a matter of fact, he is in his seventy-eighth year, having been born in Exeter, N.H., in 1846. He is one of the world’s foremost builders of telescopes. His lifetime friend and business partner, Worces- ter R. Warner, is the other. As War- ner & Swasey these two have built most of the world-famous modern giant telescopes, beginning with the noted Lick instrument, the construc- tion of which, almost 40 years ago, marked an epoch in the new astron- omy just as surely as the telescope of Galileo did in the old. Most refract- ing telescopes built in modern times have been practically copies of that first- iruit of the genius of Warner & Swasey, without which, as a noted astronomer wrote recently, modern astronomy would have been impossible. Not only in the construction of great telescopes, but in the invention and man- ufacture of machine tools, this company has achieved international fame. Its ma- chines are used today by leading manu- ‘acturers throughout the world. _ It was because of the contributions he has made to science and engineering and his benefactions to education through the

Engineering Foundation that he estab- lished in 1914, that Doctor Swasey—he is a doctor of science, a doctor of engineer- ing, and a doctor of laws—received the Fritz Medal. A day or so after his return from New York, I called on Doctor Swasey at the factory of The Warner & Swasey Com- pany, in Cleveland, Ohio. My purpose was to get him to talk about himself. But, were I dependent for information about

Alert and active at the age of 78, and with a passion for accuracy, Ambrose Swasey recently won probably the highest honor that can be paid to an engineer—the John Fritz Gold Medal. Here he is standing beside one of his marvelous precision instruments, a dividing engine for graduating circles into degrees and minutes. It is so accurate that if the circle were six miles in diameter, no division would be more than an inch out of place Ambrose Swasey on what I[ heard from his own lips, my visit would have been sig- nally disappointing. He will talk with spontaneous enthusiasm about his work, for he loves it. He will discuss astronomy, architecture, and other widely diverse sub- jects in which he is interested. But when asked to speak about himself, his conver- sation lags, and he shows unmistakable signs of being bored. It was not he, but one of his associates, who told me that his philanthropies run into large sums; that he has given more than a half-million dollars to the Engin- eering Foundation alone. Neither was it he who told me that the establishment of the school for apprentices in the Warner & Swasey factory, in which the boys and young men who enter the employ of the concern are given a thorough training in engineering at the company’s expense, was largely the result of Doctor Swasey’s memory of his own experiences as an ap- prentice boy. Nor did he tell me how as az apprentice he acquired knowledge of many sciences by studying at night and perform- ing experiments with homemade scientific apparatus while he was learning his trade. And it was not Doctor Swasey who told me that while he was a young ma- chinist in a New England shop he solved two problems that had been both- ering machinists for years. He devised a milling machine to produce gear cutters that would give to gear teeth the true epicycloidal curves. Later he invented a gear-cutting ma- chine for generating and at the same time cutting the teeth of spur gears. EITHER was it he who told me that when he was a machine-shop foreman at 33, Cor- nell University sought to persuade him to join its fac- ulty in the depart- ment of mechanical engineering as successor to the late Professor John E. Sweet, famous for his development of high-speed steam engines and himself a Fritz Medal winner 10 years ago. Doctor Swasey did tell me, though, that when Worcester R. Warner, now his partner, came to the Exeter Machine Works as an apprentice, it marked the turning-point of his life. That was in 1865, when each of them was 19. Until then, Swasey’s nightly study of the sciences had not included astronomy. Warner, though, had some knowledge and great interest in astron- omy, and Swasey caught his enthusiasm. They studied astronomy together, and years later—in 1880, when they had com- bined their joint savings of $5000 and em- barked in business together as manufac- turers of machine tools—they decided to build telescopes as a side line. The making of telescope mountings still remains a side line with them. But it is indeed an extraordinary avocation that has given to science such great instruments

Page 32

POPULAR SCIENCE MONTHLY capable of carrying on the enor- mous amount of scientific calcula- tions necessary. At last, though, we decided, ‘If we’re big enough to land a contract as large as this, we’re big enough to carry it out,’ and we engaged a noted professor of engineering to check our cal- culations.” It might be remarked here that the ex- pert they hired never found it nec- essary to make any material change in the work they sub- mitted to him. ‘There were many other prob- lems we had to solve,” Doctor Swasey continued. “We had to devise special machinery to make the parts one subject on which he is unyielding, That subject is—accuracy. Possibly I can illustrate just what Ambrose Swasey calls accuracy. A good machinist’s micrometer is calibrated to the thousandth part of an inch. Doctor Swasey makes micrometers for astronom- ical instruments that are accurate to the angular equivalent of a hundred thousandth of an inch, which is less than a waye length of light! More than that, he has con- structed and perfected a dividing engine, the most accurate in exist. ence, for graduating circles into de- grees and minutes. Its maximum error is less than one second of are. There are 1,296,000 seconds in a complete circle, which means that in a circle 40 inches in diameter, this marvelous machine does not make an error greater than 1/12,000 of an inch—less than the width of the most microscopic scratch you could make on a polished steel plate; less than half the thickness of a The world-famous 36-inch refracting telescope at the Lick Observatory, Mount Hamilton, Calif. The construction of this instrument nearly 40 years ago by Ambrose Swasey and Worcester R. Warner, marked a new era in the study of astronomy spider’s web! In a circle six miles in diameter this machine would be accurate to within an inch! OCTOR SWASEY told me of as the 36-inch Lick telescope; the 40-inch Yerkes telescope at Williams Bay, Wis., the largest refracting telescope in the world; the 26-inch instrument for the United States Naval Observatory at Washington, D. C.; the 60-inch instru- ment for the National Observatory of Argentina; the giant 72-inch telescope at Victoria, B. C., the world’s second largest reflecting telescope, through the tube of which an automobile could be driven, and the 60-inch Perkins telescope for Ohio Wesleyan University, Delaware, Ohio, which was described in the June issue of POPULAR SCIENCE MONTHLY. HE story of how Warner and Swasey obtained and executed their first big contract—the construction of the Lick telescope, which revolutionized astronom- ical research—is a remarkable chronicle of courage and achievement. When, in 1874, James Lick donated $700,000 to build at Mount Hamilton, Calif., what he specified was to be the largest telescope in the world, Swasey and his partner were not recognized as tele- scope builders. Indeed they had built only one 91-inch instrument for their own use; but they submitted preliminary drawings and a bid for the Lick telescope, proposing to produce an instrument with a standard of accuracy and an ease of operation that had been the dream of astronomers. Though they were unknown, and though their bid was the highest re- ceived, they were awarded the contract. “The scientific world was startled when such an enormous task was turned over to so small a firm as ours,’’ Doctor Swasey told me; ‘‘and to tell you the truth, no one was more surprised than we. Though we had submitted our bid in good faith and our hopes of obtaining the contract had mounted high, when the actual work confronted us, we were brought almost to the point of confessing that it was too much for us. “Since neither of us was a university man, we wondered whether we should be Sa SoS This great 60-inch reflecting telescope was completed recently by the Warner & Swasey Company for Ohio Wesleyan University of the telescope. The tube, with its acces- sories, which weighed about 20 tons, had to be mounted on such splendid bearings that it could be swung by hand. a § E WANTED ball bearings, which then were new. Nobody knew how much strain these would stand, which meant they had to be tested. So it was, too, when we decided to use a steel axle instead of an iron one. And after the instrument was completed, there still re- mained a tremendous problem—that of transporting it up a newly built mountain road along which the wind swept at 60 miles an hour. Even when the instru- ment was mounted, leading scientists who were present at its dedication in 1888 were skeptical as to its success. But the tele- scope, largest then in the world, withstood all tests and we were satisfied.” When I called upon Doctor Swasey, I found him going over with one of his en- gineers a drawing of a mechanism in which he was especially interested. “T don’t care so much for the time it takes!’ I heard Doctor Swasey exclaim, as I approached. ‘‘Work on it a year, if necessary, to accomplish the result de- sired.” Doctor Swasey intended his words to be taken literally. While in his relations with his associates he is as sympathetic and kindly as a devoted father, there is some of the difficulties that had to be overcome in its construc- tion. When, after months of tedious work, they had reduced the maxi- mum accumulated error to 1.5 seconds of an arc, Swasey’s engi- neers felt they had gone about as far as they could, and told him so. But there was another dividing engine in ex- istence that had a max- imum error of only 1.2 seconds of an arc. “T told them I wanted to get the maximum error down to one sec- ond, and I said I didn’t care if it took a year or two years,’’ Doctor Swasey said. “That is just what they did, and it tooka year.” Doctor Swasey’s characteristic thor- oughness dominates his life so completely that it is manifested even in his recrea- tions. On at least two occasions he has gone all the way around the world with- out departing from an itinerary arranged before the start. Once on an ocean trip some passengers were arguing about how far away they were from a steamship they saw at a dis- tance. Doctor Swasey took out a pocket rule, sighted the ship across its rim, and a few seconds later announced that the vessel was 314 miles away. The ship’s officers computed the distance with their instruments and found Doctor Swasey was correct. His fellow passengers mat- veled. But to the man who invented the marvelous range-. and_position-finders used by the United States Army it was merely a simple calculation. N ALL his varied accomplishments and in his mastery of tremendous problems, the creed that has made Doctor Swasey one of the greatest engineers of his time lies in his words to the engineer in his shop: “Work on it a year, if necessary, accomplish the result desired.” Ri the Oh vil the Wil

Page 33

POPULAR SCIENCE MONTHLY 33 “1 The World’s Greatest Power Dam vhat Z00d ieaieniies — - acs ae - Bis By Newton Burke yr OME time in the next reer ndth year there will be = te completed in north- western Alabama the con- greatest hydraulic de- {The dam or spilimay section 1s 3080 7eet| [Rmer house [280 Feet long, 160 7eet wide rd velopment of the present ong. Sarg. 86 fot igh from river bec Mfeet| [077 (38 fect gh in Gi pom instal xist. day and in some respects ridge. and Is 105 feet thick 3 bose.” Electric Generators lemnate power = ) de- the most tremendous uct SLT Terre num undertaking of the kind cdenerarene-- TPIT ERAT AGN DD Hp teresa acacaspaastescacezaeescn are. ever prosecuted by man. eatin ee PR BAER Tg Ts — in a It is Wilson Dam, which Ee Z_ that will contribute between al eter 200,000 and 600,000 horse- ay yn ro di te eatery re ppp nak power in electrical energy ylift 93 foot” i __ 000 to the industrial develop- : / . th of ment of the central part of How the Wilson Dam at Muscle Shoals will appear libiae completed, probably in 1925 you our Southeast, and will ; late; serve as a key in a navigation project that will be devoted to the production of ni- of a will open up a country rich in mineral, trates. The rest will be for the use of les in timber, and agricultural resources. local industries, or it can be employed in 1 be Wilson Dam is part of the Muscle furthering the development of super- Shoals development, which was begun as power through the South. a war measure to extract nitrogen from Muscle Shoals offers four distinct fields ne of the air for use in the manufacture of explo- of usefulness for times of peace—fertilizer, that sives. Electrical energy in tremendous power, navigation, and explosives. The truc- amounts was necessary in the process, and Muscle Shoals nitrate plants are said to lious Wilson Dam was projected to supply it. be capable of producing more than 200,- naxi- When the war ended, the nitrate plant 000 tons of commercial fertilizer a year. 15 was virtually completed, and Congress de- The existing equipment, however, was in- engi- cided also to finish the dam, then scarcely stalled at a time of emergency and without gone begun, as a source of industrial electricity. regard to expense, so government experts they Plans likewise were formulated for the say it will undoubtedly be necessary to M SO. construction of two other dams with a remodel it extensively if nitrates are to be other view to making navigable the Tennessee produced cheaply enough to compete with 1 eX foreign nitrogen compounds. max- y 12 a a bata — S A producer of nitrates for the manu- bines of the power plant. It is facture of explosives, however, the inted so large that a motor truck could plant constructed at Muscle Shoals during mum drive through. without difficulty the war is capable of serving an army of sec. more than 1,000,000 men, and the Wer ok a covers 20 acres of ground. When Department insists that, even should it said. completed, 36,500,000 cubic feet be devoted to the manufacture of fer- 0k a of masonry will have gone into:its _ tilizer, it must be kept in readiness for construction. The lake created munitions manufacture and be instantly thor- by the mile-long barrier across the available to the Government. etely Tennessee River extends upstream Meanwhile the construction of Wilson crea- for about “18 miles. The total Dam proceeds apace, opening to the > has cost of construction will be states of the South new prospects of ins with- somewhere about $51,000,000. dustrial and commercial development. nged The type of electric water-wheel generators to The dam hag begun ae be installed at the Wilson Dam development 1918, and it is expected ngers that it will be delivering they River through 85 miles of shoal water and power before the end of 1925. | dis- thereby providing a waterway from the Considering the amount of exca- yeket Ohio River at Paducah, Ky., to Knox- vation and masonry that its con- ind a ville, Tenn., a dream of the inhabitants of | struction entailed, the dam is the the country for more than 100 years. exceeded in magnitude among hip’s For the present the Government merely achievements in hydraulic engi- their will finish Wilson Dam and a power house neering only by the Panama rasey —hydroelectric with an auxiliary steam Canal. mal- plant—with a maximum capacity of 260,- The flow of the Tennessee River d the 000 horsepower, of which about 200,000 varies greatly. In consequence, iders horsepower would be available continu- the 260,000 horsepower that the was ously. Provision has been made, though, power house will be equipped to eventually to increase the capacity of the supply will not be available at all power house to 600,000 horsepower, and times. At low water, engineers s and it is more than likely that the rest of the say, the available energy may fall lems, plans for the Muscle Shoals development as low as 90,000 horsepower. A yasey will be carried out ultimately. supplementary steam generating Cross-section drawing of Wg time There are dams in the world that are plant, capable of producing more ps gs Ne ee Gmina n his longer than Wilson Dam, and dams that than 100,000 horsepower, how- of the water through the intake, thence to the turbine are higher, but none that is larger in all ever, will make 200,000 horse- and out into the discharge through conical draft tubes y, particulars. It is nearly a mile long and power available the year through. hat Ceaetie She Cechnges wats, See ere “anges from 95 to 134 feet high. It Of this about 50,000 horsepower the quantity of water admitted. The generator is turned by the 30,000-horsepower hydraulic turbine

Page 34

ee Col. M. A. De Laney, At- tending Surgeon, U.S.A., who ad- ministered the chlorine treatment to President Coolidge most of us do—undoubtedly you appreciate what a wide difference there is between ‘“‘ecatching a cold’? and getting rid of one. In fact, most of us who have tried the various conventional remedies, old and new, without much effect on the cold, probably would testify that there is no way to cure a cold until it has run its course. Possibly that was true a few months ago, but it’s not true now. Colds can be cured, and so easily, safely, and quickly that the process seems almost absurdly simple. You enter a small room, you sit there reading or chatting for an hour or so, and, when you come out, your cold is gone! This is because the Chemical Warfare Service of the United States Army has discovered that chlorine gas, used as a deadly weapon during the late war, can be turned to the service of humanity and employed as a remedy for respiratory diseases. That chlorine actually cures colds I ean testify from personal experience. A few weeks ago, when I entered the little room in the Munitions Building in Washington, D.C., where the medical division of the Chemical Warfare Service is administer- ing this new and amazingly effective treatment to two or thrée dozen persons a day, I was suffering from a troublesome “summer cold.” When I walked out of the little room an hour later, the cold had been knocked out—and it hasn’t come back! Nor was my experience unique. Of about 30 persons whom I saw enter that 20 at least assured me they, too, E YOU ever sufier from colds—and room, POPULAR SCIENCE MONTHLY How CHLORINE} € A Personal Experience HEN Mr. Martin, a member of the Popular Science Monthly staff, came to work with a cold the other day, the Editor sent him to Washington to try the new chlorine gas treatment developed by the Chemical Warfare Service of the U. S. Army, and to make a personal test of its efficacy. His account of his interesting experiences there, supplemented by facts he obtained from authoritative sources, is a convincing state- ment of just how much we may expect from this truly remarkable weapon against one of the most common of all human ailments. had left their colds behind them, and the others said they had been relieved. Moreover, two or three thousand per- sons in Washington and elsewhere can advance similar testimony. Presi- dent Coolidge has taken the treat- ment. So have Secretary of War Weeks and Assistant Secretary Davis. Also Rear-Admiral Rous- seau.. Members of the family of Secretary of State Hughes found relief from colds in the chlorine treatment, as did Mrs. Nicholas Longworth. At least 20 United States Senators, 100 members of the House of Representatives, 500 army and navy officers, 1000 employ- ees of government departments and almost as many more private citizens have been treated in Washington. And I 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 Division of the Chemical War- fare Service, with the apparatus used in ad- ministering the new chlorine treatment for have the word of Lieut.-Col. H. L. Gil- christ, chief of the medical division of the Chemical Warfare Service, and of Lieut.- Col. M. A. De Laney, attending surgeon of the United States Army, that not less than 75 per cent asserted without reserva- tion that they had been cured. With these, of course, must be included hundreds of others who have taken the chlorine treatment at the clinics estab- lished in New York, Chicago, and other large cities since the usefulness of chlorine as a medical known. Official records back up the testimony of persons who have tried the treatment with success. At Edgewood Arsenal, Md., where scientific methods of adminis- tering chlorine were developed, 931 per- sons suffering from various respiratory diseases were treated in the first public test and 665, or 71 per cent, were cured, 547 of them with the first treatment, which lasted an hour. Of the remainder, 218 were relieved, 198 after a single treat- ment. Only 48 patients, about 5 per cent, failed to show improvement, and almost all of these were suffering from chronic nasal catarrh, which closed their nose passages and prevented the chlorine from entering. Certainly it is an amazing contribution to medical science that fails to prove effective in only five per cent of the cases treated. Now, I don’t want to con- weapon first was made colds. Colonel Gilchrist is shown operating the valve, which permits liquid chlorine, held in the glass cylinder below, to escape into a salt solution at the left and thence to be siphoned into the adjoining chamber, where sufferers from colds are undergoing treatment vey the impression that chlorine is a cure- all. In fact, its curative powers thus far appear to be limited only to certain res- piratory diseases. For common colds, from which at least 42 persons out of every 100 suffer every year. chlorine seems to be virtually a certain cure, especially if the treatment is taken early enough. Similarly, in acute bronchitis, laryngitis, pharyngitis, whooping cough, and influenza, thus far it has cured the majority of cases. In chronic cases of ” S bron quit case’ W

Page 35

QA #4 e CURED my COLD Story bronchitis and laryngitis it has proved not quite so effective, though in virtually all cases relief has been felt. Whether chlorine will prove a cure for the chronic catarrhal affections has not vet been determined, although in many cases it has afforded relief. Also, its efficacy in severe head colds has been doubtful for the reason that swelling of the mucous membranes of the nose prevents the chlorine from obtaining free access to the affected parts. Shrinking the swollen membranes with a drug called “‘epineph- PERCENTAGE OF DEATHS EXPRESSED GRAPHICALLY 10 20 30 40 SO 60 70 80 90 100 SASES AND NO. OF CASUALTIES PO!SONOUS, KIND UNKNOWN 33,0b7 CHLORINE | 1843 | } MUSTARD GAS 27,711 PHOSGENE 6934 ARSINE | e747 This chart shows graphically the small per- centage of chlorine gas casualties among American soldiers during the war as com- pared with those resulting from other poison gases. In the chlorine treatment for colds absolute safety to the patient is assured because the gas is used in low concentration POPULAR SCIENCE MONTHLY By Robert E. Martin tain bacteria which lodge on the surface of the mucous membranes, causing colds and other common respiratory diseases, die very quickly under the action of chlorine. Obviously, if the bacteria are not present, as in asthma and hay fever, chlorine cannot effect a cure. Neither can it penetrate the tissues to attack deep-seated bacteria, as in tubercuiosis, nor can it reduce the pus-filled tonsils of tonsillitis. HE chlorine treatment is simple. You simply remain in one small room for an hour. In the case of the government clinics at Washington, the tediousness has been relieved by providing books, maga- zines, and newspapers. Also the develop- ment of a portable apparatus by means of which chlorine can be administered to a single patient permits a sufferer to rest comfortably in his own home or office whiie undergoing treatment. Despite the fact that chlorine was used as a war weapon, there is no reason why the most nervous person should fear to take the treatment. It would require about 100 times the strength of chlorine that is used in the treatment before there would be danger in breathing the gas. When the patients are seated, a valve is opened, and a small amount is fed from a glass cylinder containing chlorine in Interior of the chlorine chamber of the Medi- cal Division, Chemical Warfare Service, Washington, D. C. Persons taking the treat- ment merely sit in the chamber for an hour, reading, chatting or otherwise amusing them- selves, and in the vast majority of cases when rin,” however, has obviated this difficulty somewhat. In asthma and hay fever, the chlorine treatment, according to officers of the Chemical. Warfare Service, appears to be useless; in some cases, in fact, it is likely to have an irritating effect on the mem- branes of the nose and throat. Also, chlorine will not cure tonsillitis, tuber- culosis, or pneumonia. The reason is clear, The fundamental principle upon which the treatment depends is that cer- they come out of the room they are cured. At the extreme right is a window through which the physicians administering the treat- ment may observe the patients. Enough chlorine for a single treatment of seven per- sons simultaneously costs only about six cents liquid form. An ordinary electric fan be- side the inlet pipe circulates it through the room. When the treatment ends, all the chlorine-bearing air is driven out by fans. _ apparatus consists of a small glass cylinder, capable of holding a little more than a quart of liquid chlorine. When a valve at the top is opened, chlorine escapes through rubber tubing to a glass cylinder filled with a salt solu- tion. Thence a simple siphon causes the / President Cool- idge, whose se- vere cold recently was relieved 5 ; by chlorine gas chlorine to pass in jets into the room through glass piping. A single treatment—enough for seven persons simultaneously—costs about six cents. “One need not make extravagant claims for the chlorine’ treatment,” Colonel Gilchrist, chief of the medical division of the Chemical Warfare Service, told me. “The plain truth about it is sur- prising enough. It would scarcely be too much to say that there is no excuse now for a person to haveacold. A single hour in the chlorine chamber at a time when the cold is first felt coming on will cure it —absolutely. In the matter of common colds the treatment has proved itself be- yond question. “¥ MIGHT say also, that now we have the chlorine treatment, there never should be another influenza epidemic. “The records of the Chemical Warfare Service seem to indicate that chlorine, despite the terrible reputation it acquired during the war, is by no means as danger- ous as is popularly beljeved. The total number of American soldiers who were victims of chlorine gas during the war was 1843, and of these only seven died. So if chlorine proved no more dangerous than that when hurled at soldiers with deadly intent, no one should fear it when it is em- ployed as a medical agent and adminis- tered by a competent physician by means of scientific apparatus that keeps it always under control.” Don’t, though—and this warning comes from several officers of the Chemical War- fare Service with whom I talked—don’t try to treat yourself with chlorine! But if you feel a cold coming on, and there’s a chlorine clinic available, don’t hesitate to visit it. The writer can testify that the ga; does its work.

Page 36

29,141 FT.

MT. MCKINLEY 20,300 FT

NEWPORT. RHODE ISLAND i q —_ pb SE Cross-section diagram of the Atlantic Ocean from Newport, R. I., to the Rock of Gibraltar, showing mountain peaks, valleys, and ravines of the ocean floor. The two inserts show a striking comparison between the heights of two of the world’s tallest mountains and the By Raymond J. Brown ICTURE a place of inky darkness Pp and intense cold, a region to which the rays of the sun never have pene- trated; a barren waste seemingly unend- ing, bereft of vegetation and air, with oozy slopes inhabited by queer, crawling creatures; a place where no man could exist for an instant, where no work of man could be placed without being crushed to shapeless uselessness under a_ weight greater than all the mountains of the earth. Most of our globe is like that, for that is the bottom of the sea, as pictured by modern science. Of course, this represents the sea in its most fearsome aspect. There is a much more pleasant side to the sea; many of them, in fact. In the myriads of forms of animal life that inhabit its depths, in its abundant vegetation, in the sublime dig- nity and grandeur of its wide expanses, the sea is fascinating, beautiful, and in- spiring. Let us observe both sides of the picture. \XJO DOUBT you remember from your 4 ‘% schooldays that a little less than three-quarters of the earth is covered by water. In round numbers, the earth’s surface consists of 57,000,000 square miles of land, and 140,000,000 square miles of water. Those figures, however, give but a vague idea of the real immen- sity of the vast, mysterious sea. Any one who has seen any of the great mountains of the earth has been thrilled i’. ‘ S } MT. EVEREST

POPULAR SCIENCE MONTHLY Wonderlands Where What Science Knows about and awed by their majestic height. Yet the average depth of the sea is more than five times greater than the average height of land above sea level over the whole earth. Including our greatest mountains, the mean rise of the land above the sea is less than half a mile. The depth of the sea averages 214 miles. Moreover, more than half of the sea is between 214 and almost four miles in depth, and here and there in its basin are great caverns called “‘deeps” into which Mount Everest, tall- est mountain on earth, might be pitched and swallowed up. In fact, if Mount greatest ocean depths. If Mount Everest were dumped into the deepest pit of the Pacific, its summit, 54 miles high, would be submerged more than half a mile, while the greatest Atlantic depth would swallow all but a small portion of Mount McKinley Everest were dropped into one of these great ocean pits, its summit, 514 miles high, would be submerged more than half a mile. More surprising still, if some sort of giant scoop were to level off all the land flush with the sea and dump ali the debris into the water, the end of the task would find the sea scarcely changed at all. There would still be an ocean a mile and three-quarters deep! No man, of course, ever has visited the depths of the sea, and science says that no man ever will, because no submarine and no diving apparatus could be devised that

Government to Plumb Depths of Sea PLANS for the most complete survey of the ocean from top to bottom ever attempted recently were inaugurated by scientific branches of the government and allied institu- tions, under auspices of the Hydro- graphic Office of the U. S. Navy. Instead of a globe-girdling expedi- tion, a comparatively small section | of the sea will be selected for inten- sive study. The Aleutian Islands region of the Bering Sea and the | Caribbean Sea are now under consid- | eration as offering the best oppor- | tunities for scientific investigation. Ships will be fitted out with complete laboratories and equipped with the most modern scientific apparatus for the first cruise.

would not be crushed by the tremendous pressure of the water at even the lesser ocean depths. Through the instruments of one of the newest sciences—oceanog- raphy—-however, man has carried on con- siderable exploration beneath the surface of the huge mass of water that composes so large a part of the earth’s surface. HOUSANDS and thousands of sound- ings have revealed facts that have enabled scientists to present a nearly exact picture of the ocean basin, which they have found to be a great level plain, SPAIN

ROCK OF ~< GIBRALTAR

GREATEST PACIFIC | f TH 32iI3 FT. ~~ a R DEPTH B2IIBF —~» ¥ covered with a thick ooze formed by the bodies of sea creatures that have died since the ocean first was formed. Gravel, sand, mud, volcanic dust, meteoric iron, bits of land rocks, and precipitations from sea water also lie on the ocean floor. ‘THE deeps are not gradually sloping valleys, but long, narrow fissures, be- lieved to have been caused by earth- quakes, since they are found’in places where submarine earthquakes are fre- quent. There are also numerous moun- tains—quite as many relatively as on land. When these mountains are very high, their summits project above the surface and we call them islands. One of the most remarkable geological

—

Page 37

/ he ed el, ns an the Sun Never Shines the Majestic Depths of the Sea formations of the ocean basin is what is known as Telegraph Plateau, a great ridge that extends in almost continuous line from Newfoundland to the British Isles. The discovery ot this ocean eminence was of great importance in aiding the estab- lishment of transatlantic cable communi cation; from which fact it derives its name. OU know, of course, that most of the sea is a beautiful transparent blue. Just why this is so, science cannot say. The reflection of the color of the sky prob- ably has something to do with it. Like- wise the varying depths; for the deepest blue is found far from land, while. shallow waters, especially in the tropics, are always green. The Arctic Ocean, too, is green. Submarine vegetation here and there affects the color of the sea. Thus the Red Sea gets its color and its name from the reddish algae, or seaweed, that float near its surface. Elsewhere soil and mineral deposits from the land tint the waters near the shores. Also, the purity of the water has some bearing on its color. A tank of the purest distilled water is blue, and virtually matches in color a specimen of water taken from the sea. However, the sea is transparent and translucent only near its surface. Below 500 fathoms (3000 feet) the light of the sun does not penetrate. Hence, all the vegetation of the sea is above that level, for plant life requires the light of the sun to reduce the carbonic acid needed for its existence. Below 250 fathoms, or about 1500 feet, the heat rays of the sun cannot penetrate, and their effect is weakened considerably POPULAR SCIENCE MONTHLY A remarkable airplane photograph of the waters of East Rockaway Inlet, L. I., taken from a height of 10,000 feet, and revealing in the ocean a deep channel in the foreground, sub- merged sand bars, and a meandering stream on land at all. All the water under 500 fathoms, which means about Measuring ocean depths with the latest form of electric deep-sea sounding machine from one of the vessels of the U. S. Coast and Geodetic Survey. The greatest known depth near the coast of Mindanao, Philippine Islands, was measured in this way above that depth. The result is that there is a thin layer of warmish water on top of the sea, below which the water is cold. At 50 fathoms science has found that the temperature of the water varies little more than a degree a year. At 100 fathoms there is no change in temperature 90 per cent of the ocean, is colder than 40 degrees, while at the bottom the tem- perature is 32 de- grees, or less—just above the freezing point for salt water, which is 28 4 degrees. All of the sea is salt, though some parts are more salty than others. The degree of salinity depends to a great extent on the climate. Where the heat of the sun causes much evaporation— as in the Red Sea— a large percentage of salt is in the water. Where the evaporation is less, the per- centage of salt is correspondingly less. Throughout the whole ocean there are about 35 pounds of salt to each 1000 pounds of sea water, about 5,000,000 cubic miles in all, or more than enough to bury the United States a mile and a half The queer sea- horse (Hippocam - pus) that inhabits ° the warmer parts of the sea. It swims in an erect position and strik- ingly resembles the knight of the chess game deep. We speak generally of the “‘salt”’ of the ocean; actually we should say “salts,” for in addition to sodium chloride—the salt we use with our food—the * sea contains the salts of many other metals. In fact, the sea is a veritable treasure house. There is more gold there, for ex- ample, than ever has been mined from the land—about a grain to every ton of water. Silver is there, too, though only in about one- fifth that quantity. Thirty-two of the 92 elements known to exist have been found in sea water. Scientists believe that most of the others are there, and await merely the development of new meth- ods of chemical analysis to bring them to light. These chemicals have been washed into the sea from the rocks of the land. Every year 500,000,000 tons of salts are carried to the sea by the American rivers alone. The water of the ocean is in constant circulation; it has its rivers, its lakes, its seas. These are due to the action of the sun, which brings changes in temperature, in wind, and in the density of the water. "Ta Gulf Stream probably is the best known example of an ocean river. Starting at the Gulf of Mexico, this warm flow of tropical water skirts the American coast to the banks of New- foundland, where it takes its course across the Atlantic and divides into two streams, one flowing east toward the Azores, the other passing the shores of the British Isles and Norway and disappearing into the Arctic Ocean. The waters of the Gulf Stream are blue, often in marked contrast with the greenish seas through which it passes. It’ exerts a profound influence on the climate on many parts of the world. Thus, it carries a comparatively mild climate to Scotland, while Labrador, in the same latitude at the other side of the world, is a place of ice and cold. Similarly, Portu- gal, whose coast it washes, is extremely temperate, while a corresponding part of (Continued on page 128)

Page 38

How My Speed Rocket Can Propel Itself in a Vacuum By Prof. Robert H. Goddard HE plan of Professor Goddard to shoot a small model of a high speed moon rocket within the next few weeks, as described in the April issue of POPULAR SCIENCE MONTHLY, called forth this ques- tion from many of our readers: ‘*How is it possible, as Professor Goddard proposes, for the rocket to propel itself by successive charges ex- POPULAR SCIENCE MONTHLY Head of the Department of Physics, Clark University |: DISCUSSING the high-altitude 2, in which a blank cartridge is fired ina velocity of the expelled gases is had witha vacuum. recket consisting chiefly of pro- pellant material. There is, how- ploding in space? Since the space beyond the earth’s atmosphere is practically a vacuum, what is there for the explosions, or expelled gases, to push against?”’ : ‘A We put this question to Professor Goddard himself, 4 _ and he willingly prepared for our readers the following C scientific explanation of how he believes his rocket will ol be able to propel itself in a vacuum.—THE EDITOR. lu r The gases were prevented from re- 3 ° rocket, there is not much question as__ revolver free to turn about an axis, bounding by being shot downward into F to the long ranges possible, if a high shows that the kick occurs also in a a tubular tank, Fig. 5, in which they . circled around and around, being gradually slowed down by friction, with ia : no possibility of their rebound- [ : ever, much criticism of the idea of the rocket propelling itself at a height where there is practi- cally a perfect vacuum, it being maintained that there will be “nothing for the explosions, or expelled gases, to push against.” Contrary to common supposi- tion, however, the explosions have a greater effect in a vacuum than in the air. In fact, if the air were very much compressed, the explosions, instead of giving strong propulsion, would have no effect whatever. To see this, it must be realized that what pushes the rocket for- ward is the gas that is shot back toward the rear. Thus if a boy on roller skates throws some weights backward, he will be pushed forward by the reaction, as shown in Fig. 1. The faster he throws the weights, the faster he will be pushed forward. In a vacuum, the gases from the rocket will escape at a high speed, and the rocket therefore will continue to be kicked forward by the reaction. VERY one knows ing. Another, larger tank also was used, in which the gas was shot downward into a coil of wire fencing, which prevented re- bound of the gas. 4 t ‘TE results of 50 tests proved that there is 20 per cent greater lifting force of a rocket in Fig. 3 Fig. 4 On the other hand, if a blank cartridge could be fired in a tank containing air under a pressure so great that no gas could escape, then there would be no motion of escap- ing gases to give a kick to the revolver. Ask any engineer if he would discard the condenser on his engine, in which steam ex- hausts into a partial vacuum, and replace it by a tank under that a blank cart- ridge, fired in a revolver, produces a kick of the revolver; and the ap- paratus shown in Fig. pressure. He will tell you that if there were sufficient pres- sure in the tank into which the exhaust passes, it would stop the engine. The same principle applies to the rocket. 4! q ; —_—_>> N ORDER to test this point, a rocket chamber was fired in a tank pumped down to but 1/1500 normal atmospheric pressure. The chamber C, shown taken apart in Fig. 3, was weighed down by lead jackets L, and hung by a spiral spring S, as in Fig. 4. When the gases were fired downward, the recoil kicked the chamber upward, and the rise was registered by a scratch on a strip of smoked glass, G. The apparatus shown in _ Fig. 5 has been widely illustrated under various titles, but it simply is the device used in measuring the reaction in a vacuum. 4 A : Fig. 5 a vacuum than in air at ordinary pressure. This proof of reaction in a vacuum is but one of a number of matters that have been settled experimentally, and that will lead to rather startling results. Can you imagine two vast flaming balls—one of them 8,000,000 times our earth in volume—hurtling about each other in a 173,000,000-mile path every two weeks! Read about this wonder of the skies in next month’s issue.

Page 39

re- nto ney ally rith nd- also was vire ved rent t in

[we 2 ire. ave hat Its. ng ur ach ery of

POPULAR SCIENCE MONTHLY

39 Swindlers Who Rely.on Science Mechanical Tricks of the Carnival Bunco Man As told to Walter B. Gibson by a Retired Showman ROBABLY you know the traveling P carnival. A tented city of colored canvas booths, blatant music, bawl- ing voices, and _ jostling crowds. Calliopes and mechanical bands blaring out their noisy tunes. Flaring lights il- luminating the stands of refreshment venders, and a myriad of sideshows. Everywhere noise, hurry, and confusion. Probably, when a carni- val has come to your town, you’ve bought num- bers on a prize wheel, thrown baseballs at canvas-covered cats, or rolled little wooden balls down tiny bowling alleys, trying to win one of the many flashy prizes so en- ticingly displayed. Has it ever occurred to you how seldom you have won, or how seldom you ever have seen any one else win? The-explanation is sim- ple. While there are plenty of honest men and games in the traveling shows, many of the games of “‘chance and skill” that are prominent features of every carnival can be made cunning swindles by misuse of the principles of science. Now, a dishonest carnival gamester, or money.

“grifter,” as he calls himself, probably o ae oe ae lg COVE IF CIRCLE JN WERE ye yo NORMAL {ee ee tee gk \ { a ast ~~ a? eS er BE DROPPED CIRCLE = ——< Out OF Po. wm. \ SHAY (Y™ ii arn YH vs { “7 OSKS DO NOY COVER SPOT

The “red spot game”’ is found at almost any carnival. All you have to do to win a prize is to drop five metal disks so they will cover a painted circle. But unless you discover a trick bulge in the circle and cover that bulge first, some portion of the circle always will Temain exposed. A crooked operator knows where the bulge is by the aid of a very fine mark that a player would not notice doesn’t fit in with your notions of a scientist, and yet he is just that, for it is by employing the laws of physics and mechanics that he fixes his games to re- move your chance of winning. He’s a psychologist, too. He understands the workings of your mind and uses that knowledge to coax the money out of your pockets. The games of the grifter fall into two

general classifications—games of chance, in which you trust entirely to luck to win a prize, and games of ‘‘science and skill,” in which your chance of winning pre- sumably depends on your own ability. The games of chance usually are operated to “nay off,” allow games of so-called skill.” this type is the knife rack, where rows of and the ‘“‘play”’ is all profit. Some towns bar games of chance, but “science and One of the most popular games of attractive looking deerfoot knives line the booth. When you pause

The operator of a crooked percentage wheel says he'll pay you 10 to 1 if the wheel stops at a number corresponding to the number on which you place your To make a clean-up he deftly

PITY aTi Tt TS

ATi Hh rau ta || wiT# Leap SOLDERED ON HEAD at his stand, the operator shows you how easy it is to drop a little wooden ring over the handle in order to take away the knife as a prize. He sells you six rings tor a dime. Even if you buy a hun- dred rings, you never will = SIDE VIEW win. It is absolutely im- possible to toss a ring over one of the knife handles from the angle at which , you must throw, for the handles have slanting ends, and the knives are turned so that you are throwing the rings at the flat end of the handle that faces you, and not at the point.

HE grifter is a keen

being played. fairly, for here the well-known mathe- matical principle, the law of averages, makes the grifter a winner. When you win a prize on a paddle wheel, for example, there are always enough non-winners to pay for the prize and give the operator a profit to boot. Yet even in such a game the grifter employs his tricks to increase his earnings. HE percentage wheel is one of these devices that may be “‘gaffed’’ or controlled by taking advantage of the lO Shy AY WN LARGE Per } PITCH U UNTILYOUW law of gravity. It resem- bles a paddle wheel, but is divided into eight large sec- tions, each of which has five subdivisions. Correspond- ingly numbered sections are painted on the counter. The player places a coin on the “‘lay-down.”’ If the wheel stops at the number he is playing, he is paid 10 to 1, and if his coin is on the center subdivision, 3 to 1. With the playing price a dime and eight persons are playing, five spins of the wheel pay the operator four dollars, from which, by the law of averages, his profit will be about two dollars and sixty cents. But if all the places are not taken iad the grifter wants to clean up, he deftly places a thumb-tack, weighted with a drop of lead, on the rear of the wheel opposite a number that is not being played. The weight of the tack causes the wheel to stop at the ‘‘open’”’ number; consequently, the operator does not have pushes a leaded thumb-tack into the back gist. of the wheel opposite a number that is not How he takes advantage of the law of gravity to take your money is shown in the side-view diagram practical psycholo- He knows that you come to a carnival to have a good time, and that you are willing to pay for it. Take the “three-pin game.”’ All you have to do to win at this is to roll a little ball down a miniature bowling alley and knock over three ten- pins. If you do it, you get a dollar bill. But you never knock down more than two, because the two front pins are so set that the ball passes between them without striking both at the same time. If you get discouraged but look prosperous, the operator displays more of his “art,” using a confederate known as a “capper”

Attempting to throw a ring over one of the winning pins on a crooked clothesline game is hopeless. If you win you lose; for the gamester has selected winning numbers that he can transform into losers by the simple process of turning the pn upside down or a “shill” to lure you on. The confed- erate can make a perfect shot every time, because the operator has set the pins closer together for him. The swing ball game is a notorious gold- mine for the grifter. Here a ten-pin

Page 40

POPULAR SCIENCE MONTHLY center of gravity so that the ball = may easily knock the cat to the yA ground. “ro Another ‘‘game () of skill” is called DOTTED LINES SHOW “FRAME SHIFTED TO LEFT | } { | | t ! : 2 ' It looks easy enough to knock over a ten- SWING OF BALL os 4 (Q): ' f ‘. FRAME FRAME if TOLEFT TO RIGHT a= 6 Fi HOLE IN BOTTOM OF ---“77S3, PIN OFF CENTER “Yo BALL MUST BE SWUNG \_/’ FROM RIGHT OF PIN “Pigs in Clover.” You tip a board to roll half a dozen balls through spikes into num- bered pockets at the other end. Low scores give small prizes, high scores ‘‘grand’’ prizes. These games are con- trolled by setting PIN TURNED TO RIGHT *s . TOP { } ‘VIEW! | (7)... h rt norma? | i : 1 | POSITION |: 1! ' / + OFBALL J.) \\ ' a G pin with a swinging bowling ball suspended from a frame above. The game is simply to swing the ball to the right of the pin so that it will strike the pin coming back. But if a grifter is operating the game dishonestly, either he shifts the unsteady frame, throwing the ball off its course, as in A, in the diagram above at right, or he places the pin off center, out of the line of swing, as indicated in B stands on a counter lined with the in- evitable flashy prizes. Beside the pin hangs a bowling ball suspended from a frame above. The game is to swing the ball to the right of the pin so that it will knock the pin over on its re- turn swing. Purposely faulty construction renders the frame wabbly, so that the operator has only to lean against it to throw the ball from its course. The pin also is made lopsided and off center to set the game against you. To knock a large canvas tom cat from a rack only a few feet away with a ball seems like an easy way to win a prize —but try to do it! The cat leaves the rack only when the shill tries his luck. In this case the gamester uses a little —~ width’. ( Ace OF aes FIc.3 “enone ‘ d'or & “BALL YIG2 The “‘three-pin game’”’ looks easy. a grifter wishes, it is impossible to knock over all three pins, because the two front pins are farther apart than the width of the Yet, if ball, asin Fig.1. The grifter’s confederate, however, finds it easy. For him the pins are set closer together, as shown, in Fig. 2 physics to cheat you. Inside of the cat is a movable weight. Pushing this to the bottom practically anchors the cat to the shelf by lowering its center of gravity to its base. When the shill throws, the weight is shifted to the center by tipping the cat upside down. This raises the LL PRIZES -NO BLAN' . 2.75 ))RED NUMBERS ([0) ; WIN LARGE PRIZES 7 NUMBERS 10-4F20-30-3§M0-4150-SiWN YOUR CHOICE OF ANY PRIZE.OX STAND aortas NUMBERS WW Sie Ph Sas oncy one or two spikes in front of important holes, or else high or low numbers are lacking so that only moderate scores can be made. Don’t think, however, that the career of the dishonest gamester is a bed of roses lined with greenbacks. Quite the oppo- site. Frequently he is compelled to pay big money to grafting officials before they will permit him to run his game, or he may be forced to pay very high rentals for his booth space. To avoid these hazards a class known as “small-time grifters’ has operator. After ringing the bell once or twice, players always seem to lose strength. The track on which the lead weight travels is connected with one of the guy wires. When you start, the grifter leans against this trick wire, tight- ening the track and allowing you to score. When he takes his weight from the guy wire the track becomes slack and the weight bumps against the post. When the wire is slack, Samson himself could pound all day and never hit the bell. } O GAME is too large or too small to be controlled—not even the small ‘‘roll- down” or “haphazard” games that con- sist of glass boxes into which marbles or coins are dropped to roll toward a row of pockets protected by protruding nails. These games are “fixed” by a movable row of concealed nails, which may be shifted to open or close the winning num- bers. One of the games that call for a little skill is the red-spot game. You'll find this game at almost any carnival. All you have to do to win is to drop five three-inch metal disks so that they will cover a painted circle. It happens, though, that the so-called circle is slightly lopsided. Some portion of it always will protrude unless this bulge is.first covered. Only the proprietor of the game can pick this out with the aid of a very fine mark that players never notice. They fall for it because it looks so easy. Yet I would not have you believe that all games’such as THUMB COVERS a e . . TOPS OF LOSING are mentioned in this article NUMBERS TO MAKE . THEM APPEAR AS are dishonestly operated. In a large number of them the house is content to let the mathematical law of averages take its course. It is with the tricks of the swindler that I have been dealing. Phineas T. Barnum, who was the greatest of all show- men, summed up the lure of When business is slow and the gamester’s the carnival games in one im- mortal sentence, ‘‘There is one born every minute.” confederate appears to lure you on by winning a prize, a simple expedient to make him win is to cover the tops of losing numbers with the thumb, thus making them appear as winning numbers sprung up. Their games are com- paratively primitive. One of these games is known as the string game. The operator holds a hand full of loose string ends, which pass over a rack and are attached to a shelf full of prizes.- All you are asked to do is to pick a string and take the prize attached to it; yet you never get anything but a worthless trinket, because the cords attached to the better prizes are doubled back in the grifter’s hand out of sight and reach. The grifter’s ingenuity is shown by the way he “rigs” various forms of “strikers” that appear to be genuine strength-testing machines. The “high striker” on which the player swings a wooden mallet to drive a lead weight up a long wire track to strike a gong, likewise is subject to control by the CENTER OF GRAVITY CENTER OF GRAVITY SLIDING WEIGHT ft IN CAT When you try to knock the canvas cat from the rack with a thrown ball, the dishonest gamester has you at his mercy. In some such games, inside the cat is a movable weight. Shifting the weight to the bottom practically anchors the cat to the rack by lowering its center of gravity Don’t join that number by rushing blindly into the grifter’s hands. Patronize the rides and legitimate booths that you know are genuine and the gambling parasite wi!!! quickly fade away. A.N A anotk findir probl most with to WT tucke three bath apart The and nien¢ ly th freed | forts John the ¢ cided No cerne to ex inar venie me work © freed since night let’s. W whic almo plex forni: those that build each Ther fami. » meet clina of tk and | pays inter Nc othe: the | say } and - The} possi writi dup! thou built John rent didn say; to h B extrs T | dup] dup!

Page 41

or se ad he it- re. uy he en ld ‘2. dly the low : YEAR or so A ago,John and I, like many s work for me; * freedom he desires. POPULAR SCIENCE MONTHLY 41 AFive-Room Homein Three Rooms How We Designed a Duplex Bungalow that Pays for Itself By A. May Holaday another couple, were finding the housing problem about the most difficult one with which we had to wrestle. We were tucked away in three rooms and bath in a large apartment house. The rent was high, and other inconve- niences—particular- ly the lack of room, freedom, and com- forts — from which John suffered, made the conditions under which we lived de- cidedly unpleasant. Now, though, so far as we are con- cerned, the housing problem has ceased toexist. We are living virtually rent free inareal home with every comfort and con- venience we could wish for. There is less John has all the room and Months have passed since last I heard what used to be his nightly plea in the apartment: “Come on, let’s go some place—any place!’ low wer we have done any other couple can do also. The way in which we solved the housing problem was f almost absurdly simple. We built a du- plex bungalow. People who live in Cali- fornia will know what I mean. But for those who live elsewhere I’d better explain that a duplex bungalow is a one-story building divided into two apartments, each consisting of three rooms and bath. There are separate entrances, and the two families occupying the apartments need meet no more often than their social in- clinations direct. Usually the builders of the ‘‘duplex” occupy one apartment, and the rent they receive from the other pays the expenses of the whole house— interest on mortgage, taxes—everything. Now, fellow Californians and other people who have heard of Front view of the at- tractive duplex bunga- ingeniously de- signed by the writer. The detailed floor plan and side elevation are shown at the right It was I who first suggested the duplex as our solution of the housing problem, and when I persuaded John to go with me and look at some, he discovered more objectionable features in them than he’d found even in our apartment. DUPLEX, of course, occupies only one lot. Therefore, the only feasible arrangement of rooms is one behind the other, the same scheme used in the old- time “railroad” flats. A living-room in front, then a dining-room, then a kitchen, and a bath in the rear is the conventional 99 ° . plan. ‘Bedrooms” are provided by in- °o — T = , = r i 7 2 ce ee! = — — (a \ y] DEADENING FELT BET.2°STUDS— |[oms ~7 Wg SCREEN . ° coon Ms i oe D > ety 7 Pe x % VENT IN FLOOR pase [SOS A 2026 wilo 9 =e #8 oN eee eactien : ¢i7 of Ex] UVING-ROOM eae SURE ee Al s 4 © &? o8 3 ot | '.} power v4 ¥ = + 5+ se ¢ oO OX] th PLUG & i is ‘ ar 320 St (acy Se 4 ¢ “b> j otis [0 : BOARD = 24X6-8 2 f aed ta § \ pooxcase - fa = 4 5 Yi SLEEPING a AND DESK be FOLDING KITCHEN = ae PORCH > Sa“ | TABLE g we ey ze alq/\Cl 2 SEAT sieyr WED. CASE —-s = So 9° 30X4-6 as x +0%4-6 e-6X4-@ DO F4XF0 HASO S01 DO > s] 14-0 14-0 “[-— 6-0—o} a the world. It took a lot of pondering and _ pencil-chew- ing to do it, but we succeeded in obtaining all the comforts of a five-room apartment in three rooms. We utilized every square inch of floor space and wall space. We achieved not only J === SCR.VENT TO COOLER SIDE ELEVATION the appearance of roominess, but roomi- ness itself. Actually we have only three rooms; still, John and I never are in each other’s way—we have even a spare bed- room when we are entertaining a guest! _ AIR DUCT BET. JOISTS stalling wall beds that fold back in the daytime, in the living-room and dining- room. To get from the living-room, say, to the kitchen, you must pass through the dining-room, for doors opening from one room to the next offer the only way of walking from front to the duplex plan are going to say right here that what John and I did was nothing unusual. They’re going to wonder what possible excuse I can give for Writing an article about our duplex, inasmuch as many thousands of them had been built and were occupied while John and I were still paying tent for an apartment. We didn’t invent the duplex, they'll say; hence, what right have I to herald what we did as an extraordinary achievement? True, we didn’t invent the duplex; but we did design a auplex—the one we are living in—that is unlike any other in A corner of the living-room, which becomes a bedroom at night. The door to the bed closet, at the right, is made attractive by a silk drape. The door leads to a service hall, giving access to other rooms back. After we’d inspected a few, John informed me that so far as he was concerned, a duplex was not for us. “T’d just as lief live in a tent!’ were his exact words. “I’m used to sleeping in a bed- room, and I’m not going to sleep in a dining-room for any- body! Another thing—a bath- room ought to be convenient. I don’t intend walking through two or three rooms to shave! We’d better stay where we are. After looking at these things, I find the little old apartment isn’t so bad after all.” To tell the truth, I was a

Page 42

POPULAR SCIENCE MONTHLY dining-room without sub- jecting ourselves to the unpleasant necessity of eating in the kitchen, for between kitchen and liv- ing-room we placed a nook,” easily accessible from both living-room and kitchen, yet quite re- moved from all kitchen “clutter.” Beside this, at the cen- ter of the back wall of the living-room we placed a ventilated bed closet. By day there is nothing in the The airy bedroom is transformed into a sun- room or sewing-room by folding the bed into a closet. One quick movement raises the bed, lets the footboard drop and closes it up little bit disappointed myself. We were cramped in the apartment, but the ar- rangement of rooms in the usual duplex seemed to offer no relief from that. Also, I couldn’t help but admit that the other objections John had raised were sound. ND then all at once a thought struck me: Just because the room arrange- ment in all the duplex apartments we’d seen was unsatisfactory, it was no reason why our duplex should have an unsatis- factory floor plan! What was to prevent us from designing a duplex of our own, and eliminating the objectionable fea- tures? I expressed this thought to John. He merely laughed at me. **Who told you you were an architect?” he demanded. “Nobody,” I said; ‘but I’m going to design a new kind of duplex.” And I did—and we’re living in it today. It wasn’t done as quickly as all that. My first rough sketches, I’m afraid, were quite impossible. But there was an idea behind them, and when I showed them to John, he became so interested that he vol- unteered to help me, and between us we worked out the problem. The first thing we did was to provide a bedroom that was to be a bedroom and nothing else. The rear seemed to be the logical place to put it, so that’s where it went. Since the bathroom should be convenient to most charming “breakfast . A cozy dining-nook between the living-room and kitchen. Double French doors sep- arate it from the living-room if desired. The table folds up appearance of the living- room to denote that, when we have a guest, it can be- come a bedroom at night. Yet the bed turns easily out of its closet on its heavy door, and behind it appears a roomy, ventilated, elec- tric-lighted dressing-room. There are clothes hooks, ample shelf space for suit- case, and a full-length mir- ror on the inside of a door that leads into a service hall. That service hall we regard as the crowning achievement of our venture into architecture. Probably the bedroom, the obvious location for it was next to the bedroom, so that’s where that went—toward the front of the house. Next came the kitchen; then—well, what was the front room to be—living- room or dining-room, or a combination of both? It was quite a problem, and its solution required much more ingenuity than either of us suspected we pos- sessed. We decided at last that the front room was to be a living-room, and that we'd dispense with a din- ing-room entirely. More- over, we eliminated the roomy towel The bathroom, showing toilet cabinet with mirror door and more than any other fea- | ture of our duplex, it makes the apartments— ours and our tenant’s— real homes. And very easily, too, we arranged for it, once the idea of providing a hall occurred! We merely cut a four-foot strip from the inner side of kitchen and bathroom — space that could be spared easily— and behold! there was the hall, with a door leading into each room! No neces- sity of crossing one room to reach another! At the ends of the hall are French doors, admitting light whether closed or open. That, in a few words, cabinet below This small but convenient enameled kitchen has plenty of drawers and cupboards, as well as a built-in ironing-board that folds down near the gas-range, when it is to be used describes the general plan of our dupler The feature that has attracted the mo comment from visitors is the breakfay nook, which we use for all meals. Whe, the double French doors at the living room end are thrown open, the nook i. comes a part of the living-room, and giys an appearance of spaciousness that j quite amazing. Closed, the gauze dra on the glass doors conceal the table and benches from view. The nook then i part of the kitchen. When necessary, one leaf of the table which is portable, may be dropped, thy affording a passageway between living. room and kitchen. Di gcmahad comfort received first consider. tion when we planned the bathroon, Two windows, with a shaving cabinet an a large mirror between, and an electr): light above, give him all the light he needs for shaving. A towel cabinet beneath th mirror supplies John with a dressing-table Five windows in our rear bedroom giv: us sufficient reason for calling it, as we do, a “sleeping porch.” It is light, airy, quie —has all the advantages a_ bedroon should have. The wall bed is easily py out of the way during the day. In the kitchen are drawers and cup boards aplenty. A “cooler’—a tall cup board with heavy wire shelves, vented top and bottom, holds vegetables, mil and similar supplies. There is a built-in ironing-board that folds down near th white-enameled gas-range, allowing plenty of room for ironing. We also have supplied abundant clost ‘room. The dressing-room behind the wall bed of the living-room supplies a! admirable clothes closet. There is a linet closet in the hall, also a broom closet large enough to contain the entire cleanilg equipment of the apartment. We havei rear porch, containing a wash tray. Ther are inside steps to the small cemented basement, and an automatic gas-heatel that supplies hot water in kitchen, bath, and wash tray. A combination bookca* and desk is built into the living-room. F YOU’RE tired of paying out remh or desire to live in your own home for any other reason, I commend to you! duplex bungalow of the kind that Joh and I built. If the duplex plan has ne yet reached your section, don’t discard it for that reason. Maybe you can start the style in your town and win fame for you" self while you are building your home! In

Page 43

POPULAR SCIENCE MONTHLY 43 % & “tInsect Hobgoblins of the Tropics ast ie Midget Tree-Hoppers Show 00k e e te Nature in Fantastic Mood be Tree-hoppers of India and South America are the newest then i insect wonders presented to the public by science. They are tiny and gorgeously colored, and probably the most grotesque creatures that ever came under the microscope. , The pictures on this page are from greatly enlarged wax ; models prepared at the American Museum of Natural History. Note the intricate, swordlike horn curving over the back of the Brazilian specimen, shown just below = 7 a e table d, thus living. nsiders. ' : — y : throom, net and electric 1e needs ath the g-table, Om give S we do, Y, Quiet edroom sily put nd cup all cup vented eS, milk This specimen also is a native of Brazil. It has four built-in eyes—two large protruding upper ones, and two below, lear the partly developed. The upper eyes have a keen, droll look, and the line that separates the head in some instances gives it the appearance of wearing spectacles. “Rta It has three pairs of legs, the longer being behind. With these it is able to jump considerable distances This insect, from India, suggests a turkey glancing backward. It has an anvil-shaped hump on its back. Underneath are the wings. Entomologists have not been able to tell why these specimens need horns that seem to be only in the way. These hoppers are the great- est change artists on nature’s stage. They possess the amazingly useful power of alter- ing their shape and size from day to day nty of -board > used g plenty rt closet ind the plies at is a linen set large cleaning 2 have’ r, There emented is-heatet n, bath, yookcas? room. ut rent, n home to yous at Joh has no iscard it start the or your ome! With its unusually long appendage this Indian specimen bears a striking resemblance to a giraffe. Note its eyes just above where the legs join the body. They suggest automobile headlights. This creature is even more clumsy in its movements than some of the other awkward tree-hoppers

Page 44

POPULAR SCIENCE MONTHLY In the laboratory of the U. S. Bureau of Chemistry—making excellent tea from the leaves of the wild cassina plant How Chemistry Is Feeding Us ORE and more the world is coming to realize to what a startling and almost incredible degree the application of scientific knowledge has changed the Back of our modern engineering and mechanical marvels, our automobiles, skyscrapers, airplanes, and bridges, stands the scientist, working in his laboratory to supply the materials of new and improved quality without which the triumphs of aspect of productive industries. the engineer would be impossible. In every direction eager experimenters are on the track In seeking ways to eliminate waste of new discoveries. HERE used to be a play called “The Old Homestead”? that was very popular. In it Josh Whitcomb, a sweet-natured and unsophisticated old farmer from Swazey, N. H., went to New York to look after a boy. The marvels of the great city had their effect on him. Having written home, he asked a passing stranger to direct him to the post-office so that he might dispatch his jetter. The stranger pointed out a mail- box, and said if he deposited it there it would surely reach its destination. The farmer followed the advice; then, turning slowly farms. in the production of power, they are searching radio- activity and the atom for new sources of energy. wise, to meet the world’s demand for food, they are studying new methods of increasing the productivity of the soil and of eliminating waste effort on the Like- It is this last field of research—science on the farm — that Doctor Hendrick discusses here. His is a fascinating and authoritative article on the achievements of synthetic chemistry in answer to man-made demands. — THE EDITOR. By Ellwood Hendrick, Sc.D. to do it—there isn’t power enough avail- ally. The farm is not to be supplanted by the chemical factory, although the farm already is beginning to draft the chemical and biological laboratories for its own purposes. Even if we chemists could make up tasty and nutritious foods out of in- animate matter, instead of out of things that have been through the processes of life, out of things that have grown on the farm—and it’s a fact, we don’t know how able to make the food for the world in factories. We should require coal ot water power or fuel oil, while the plants and trees use the power of light direct from the sun for their growth. We cannot use light for power. Every green leaf has us beaten in this respect. Again, our internal organs are so con- structed that if we undertook to live on tablets without the necessary roughage or coarseness of food, they would collapse and the whole world soon would come down with an international away, he exclaimed, ‘‘Now, by gracious, I suppose that letter is halfway up to Swazey!”’ Now we, who used to chortle at the credulity of the old man in the play, very often are like him when the talk is about science. There are some of us, for example, who be- lieve that we soon shall have all our food made in chem- ical factories out of air and water and carbonic-acid gas; that even farming soon is to be a thing of the past, and that chemically prepared food will come to us in tab- lets that we shall nibble. bowel complaint. Let’s keep our feet on the ground. Men of science have to do so. UT don’t be disap pointed. Science, work ing along practical lines, ‘already is accomplishing amazing things in solving our food problems. Cot sider, for example, the prob lem of obtaining nitroget fértilizer so vital to ou farms. Four-fifths of the air is nitrogen and _ plants must have nitrogen in com bination—fixed nitrogen, as it is called—to grow. Now nitrogen fertilizer from the air already is being madeon! largescalein Germany. Als, These notions are mere guesses, unsound economic- Dr. H. C. Gore, of the U. S. Bureau of Chemistry, converting corn into a new sugar cheaper than cane sugar and sweeter than glucose Dr. A. Larson, of the U. s. Government’s Fixed Nitro gen Rese process t as the G Anoth fertilizer haven’t and so | fertilizer or earth. to mixir cals him: on freigt GAD su out of | rock and cern is €: acid fror waste b lean as and ge crystals Humvu vegetabl very fin product soil for plants. fair that sewage That is, towns, streams health, separate destroys then wi ally het fluid ch wholly | no dam the str solid wil that it offensiv: that is other cl Anot] of humi develop ment § stalks, ; by mea and in 1 the det

Page 45

POPULAR SCIENCE MONTHLY 45

gen Research laboratory, has worked outa ideal humus, fairly rich in nitrogen. principal constituents of the plant, giving process that is nearly doubly as effective Straw now is burnt as waste on the great back oxygen to the air. In iron blast as the German method. wheat farms. furnaces the exhaust gases contain large Another problem in connection with Such scientific feats demonstrate how quantities of carbonic-acid gas that put fertilizers is that of mixing them. Farmers much may be expected from our chemists out fire, together with other gases that haven’t been able to do this very well, in making food indirectly from waste will burn. It is profitable to separate the and so have paid freight on 20 per cent stuffs. So also does the way in which carbonic-acid gas from the others, using fertilizers mixed with 80 per cent gypsum _carbon-dioxide from the stacks of blast the Jatter as fuel. But instead of wasting orearth. But the farmer is coming around furnaces is being piped to farms and _ the carbonic-acid gas, it can be flooded to mixing the necessary chemi- over neighboring truck gardens, cals himself. Think of his saving and thus cause a luxuriant on freights when he does! growth of vegetation. Industrial alcohol works also produce vast quantities of this gas, and it may become profit- able to produce it locally if limestone is available and _ if near by is some industrial estab- lishment that produces a waste acid.

GAIN, instead of making “superphosphate” fertilizer out of finely ground phosphate rock and sulphuric acid, one con- cern is extracting the phosphoric acid from the rock, avoiding the waste by washing, using the lean as well as the rich rocks, and getting the pure white erystals available for use. Humus, the result of decayed vegetable matter in a state of very fine particles, is another product greatly needed by the soil for the vigorous growth of plants. Now the prospect is fair that within a few years the sewage problem will be solved. That is, the sewage of cities and towns, instead of polluting streams and threatening public health, will have all grease

S° MUCH for making the soil more productive. In the meantime it is well to bear in mind, to the credit of the Ameri- can farmer, that in the 20 years following 1900, he not only fed and clothed the American peo- ple, but exported wheat and other grains, allayed starvation in China and Russia; and this despite the fact that at the end of the period he was cultivating 11 per cent less acreage than at the beginning, with 33 per cent

D-

< separated from it, because grease fewer persons to work for him; re | destroys the fertility of soil. It for within that time some 4,000,- ty then will be divided mechanic- 000 workers transferred their re | ally between fluid and solid, the activities from agriculture to fluid chlorinated and rendered industry. We mustn’t kick if ; wholly harmless, so that it does the farmer is a little slow in

. no damage even to the fish 11 adopting some improvements. 1E | the streams. The sludge, or bes ; Dp He is short-handed. solid will be so treated and dried =e ae caged eo Pai oasis One important means of con- 4 . . 1 1 e syru rom unmarketa a Ss ~y _ 2a liec avail i that it bec pannget -” odorless, in- ‘ide uaa ose of about 40 per et of amine crop. serving the food we produce lies aval offensive, low nitrogen fertilizer In the process developed by government chemists, the potatoes are in canning. The American Can- rid in that is ideal for mixing with boiled, treated with a little malt, and crushed until they yield a juice ners’ Association maintains a yal or other chemicals. that is reduced by evaporation to a syrup resembling cane syrup large research laboratory in plants Another very valuable source Washington where improve- direct of humus will come from a process under so made to increase the yield of crops. ments in factory methods, in the taste ‘annot development at the Rothamstead Experi- The leaves of plants and trees take in and keeping qualities of food products, af has ment Station in England. Straw, chaff, water vapor and carbonic-acid gas from and the avoidance of waste, are worked stalks, and other farm waste is fermented the air and by a remarkable chemical out. Canning alone saves a vast tonnage by means of a special enzyme, or yeast, process, using the light of the sun for of fruits and vegetables every season. and in two or three months turns into an __ energy, resolve these two vapors into the (Continued on page 131) 0 con ive on ighage lapse SS come | itional | 's keep 1 1. Men $0.

disap- work: lines, lishing solving Con- e prob- trogen to «(Our of the plants n com gen, a Now om the 1deona y. Also, ie U. s. Nitro-

roger has supplanted the “rule of thumb” in the flour industry. In values, and deficiencies are remedied, with the object of making each slice q o days the miller felt the flour between his forefinger and thumb to of bread a perfectly balanced ration of food. The woman in the picture is Getermine its quality and texture. Today elaborate chemical laboratories testing the ash of burnt flour in a New York flour mill and is one Te part of every great milling plant. Here flour is tested for nutritive of a large staff of expert chemists who are regularly employed by the mill

Page 46

POPULAR SCIENCE MONTHLY Practical Science in the Making A Review of Recent Discoveries and What They Hold for Yoy The X-ray has ee been made avail- ne 5 able for home use by a portable ap- paratus trams- ported by auto- mobile. Power from a dynamo mounted on the hood of the car is supplied through a cable taken into the house | Aiea 5 p: a %¢/) ‘ ! Neer ARBON dioxide, or car- bonic-acid gas, may be described as the “‘smoke”’ of the body fires. We exhale it from our lungs as ‘‘waste’’ after the oxygen we have previously absorbed has been utilized in the “burning”? process that replen- ishes the tissues. It is carbon dioxide issuing from many lungs that causes theaters and similar gathering places of many people to become ‘“‘stuffy.”” Carbon dioxide will not support animal life. In fact, in a concentration of four or five per cent in the atmosphere it may be fatal. It is somewhat amazing, then, to learn that science has dis- covered that this gas, which will itself asphyxiate, is more potent than fresh air or even oxygen in reviving partially asphyxiated persons. And quite as astonish- ing is the suggestion recently made that this gas can be used to cure tuberculosis. The value of carbon dioxide in cases of suffocation is made known by Professor Yandell Henderson, of Yale University. The gas is normally present in the lungs and blood where, Professor Henderson says, itis necessary to stimulate the nerve cen- ters that control breathing. Fresh air or pure oxygen administered to a victim of asphyxiation, he asserts, tends to depress the nerve centers of respiration and make breathing more difficult instead of improv- ing it. TOR is this merely a theory, for Pro- 4 fessor Henderson and his associate, Dr. H. W. Haggard, have devised a breathing apparatus that automatically mixes about five per cent of carbon dioxide in the air supplied to a suffocated person. The effect is said to be a remark- able stimulation of breathing, so much so that victims of illuminating gas, carbon monoxide, and smoke, and surgical pa- Experimenters operating the portable X-ray apparatus, invented by Prof. A. M. Low, noted British scientist, to examine the quality of metal tients after anesthesia recover entirely in a few hours. Dr. H. J. Cooper, tubercu- losis authority, of Denver, Colo., asserts that carbon dioxide may furnish a cure for tuberculosis. Experi- ments with thousands of animals, according to Doctor Cooper, show that the growth of tubercle ba- cilli is arrested by three per cent carbon dioxide, while the bacilli are killed by 15 per cent. , It is Doctor Cooper’s sug- gestion that the injection of carbon into the blood, in quantities so minute ,that the tiny blood vessels will not be blocked, will result in the depositing of carbon in the lungs and consequent formation there of carbon dioxide in amounts suffi- in a carburetor cient to kill the germs of tuberculosis Remarkably enough, at just about the time that Doctor Cooper was making this announcement, from the Pastey Institute in Paris came word that Pro. fessor Albert Calmette, assistant director a noted tuberculosis expert, was ready to demonstrate an anti-tuberculosis vaccine to the development of which he had de. voted 20 years. This is not a tuberculosis cure. All that Professor Calmette promises for his preparation, which he calls “B C G,” js that it will prevent the development of tuberculosis germs in persons who are inoculated with it. Tuberculosis is one of the few germ diseases that medical science has not yet conquered, Efforts such as those just de scribed, however, undoubtedly will result in the contro! and eventual elimination of it. Gun Ejects Airplane HOOTING an airplane out of a gun probably sounds like some imaginative novelist’s sug- gestion, yet just exactly that was done in a scientific test ofa new method of putting aircraft into flight, conducted a few weeks ago at the Naval Air Sta- tion, Washington, D. C. Before long this may become the stan- dard method of launching air planes from war-ship decks. The plane is placed on a small car, mounted on tracks that end at a platform on top of a battle ship’s turret. The car is con- nected by a series of pulleys with a piston inclosed in a gun When the gun is fired, the piston is driven forward, pulling the car almost instantly into a speed of To improve the quality of American-made Swiss cheese, the U. S. Bureau of Standards has perfected this cheese-testing X-ray A dairy expert of the Bureau is shown examining 4 cheese to determine whether it has aged sufficiently 60 mil tracks the Ca off, Cor This compre The ple in altit powder! the cor Also. one aft pe relo HI tc mined helicoy have auspic them, devise can fi perfect Tes' have secret. Des word that 1 pable more, sidera ing ur The has ry horize Exp! pe er not 01 only | offere

Page 47

“ou -ulosis, ut the naking asteur t Pro- rector, ady to "accine ad de. 1 that or his G,"? is lent of ho are he few nedical yuered, ist de. ibtedly ol and it. lane > out of ds like ts sug- y that est of a aircraft a few \ir Sta- Before e stan- ng. ait ks. a small hat end battle is con- ys with a gun. > piston the car peed of se, the , X-ray ning 4 g9 miles an hour. At the end of the tracks hydraulic and spring buffers stop the car, and the plane is catapulted off, continuing under its own power. This method is said to be superior to the compressed-air catapults previously used. The plane continues its flight with no drop in altitude, probably because a charge of powder supplies greater momentum than the compressed air. Also, it permits the launching of planes one after the other as fast as the gun can pe reloaded and the planes set on the car. A New Helicopter HE British Government, according to recent reports, is making a deter- mined effort to develop a practicable helicopter. Several British inventors have tackled the problem under the auspices of the Air Ministry, and one of them, Louis Brennan, is said to have devised a machine that POPULAR SCIENCE MONTHLY tion until recently, when the American Geographical Society established a school for explorers in New York City. Dr. Ham- ilton Rice, well known South American explorer, conceived the idea of the school, and is its director. The scheme of instruction will be en- tirely practical, based on the experience of noted explorers. Of course, in the country around New York, where fieid instructions will be given, the students will not experience the rigors of the jungle or the arctic regions, but the conditions of actual exploration will be simulated as well as possible. Thorough instruc- tion will be given in surveying, map- ping, and field astronomy. Science Finds a Way OME time ago scientists from the Smithsonian Institution estab- lished a meteorological station can rise and descend in perfect control. Tests of the machine have been made in secret. Despite § precautions, word has been received that the machine is ca- pable of rising 25 feet or more, hovering for a con- siderable period and land- ing unhurt. The Brennan machine has not been tested in horizontal flight. Explorers’ School prok explorers, experi- ence always has been not only the best, but the only teacher. No college offered a course in explora- Here is Dr. William V. Linder, chief chemist of the United States Bureau of Chemistry, under whose direction 80,000 samples of bootleg liquor have een analyzed by Uncle Sam this year. Of these, 72,000—or nine out of 10 samples—were found to contain poisons, including carbolic acid, hydro- chloric acid, formaldehyde, acetone, and iodine lights. on a mountain in Chile. The purpose was to measure the heat of the sun to discover what relation exists between changes in the sun’s heat and our weather. Elaborate mathematical calcula- tions were performed mostly at night, for during the day the scientists were engaged in making observations. The primitive oil lamps and candles that were the only means at hand for sup- plying light for the night work were unsatisfactory to scientists who were accustomed to working in well equipped laboratories. The necessity for electric lights was apparent—but how were they to get them at the peak of a desolate mountain? Recently they found a way. They built a windmill, installed a dynamo and storage batteries, and now their observatory, hundreds of miles from the nearest inhabited place, is as well lighted as if it were in the heart of civilization. Thus does science triumph over obstacles large and small. To demonstrate the theory that atoms of matter are com- posed of electrons revolving, like planets in a solar system, around a central nucleus, the General Electric Company has installed in its research laboratory the model atom shown above. The electrons are indicated by small electric Thus the theoretical arrangement of electrons in an atom of any given substance can be visualized Prof. F. B. Littell, of the United States Navy, using the world’s most perfect zenith tube at the Naval Ob- servatory, Wash- ington, D. C., to measure variations in latitude in the earth’s movement © Harris & Ewing From measurements with the zenith tube at Wash- ington, and from observa- tions at other astronomical observatories, it has been determined that the axis of the earth’s rotation changes its position con- tinually. The North Pole moves around in a circle varying from 30 to 60 feet in diameter, completing the circuit in about 14 months TOUT persons, anxious to “reduce,” usually make a special point of avoiding sweets. This is a mistake, according to Dr. James McLester, of Bir- mingham, Ala., who says that sweets offer a valu- able weapon to those who would lose weight. Too much food, says Doctor McLester, is the usual cause of corpulence, and a slim diet offers the ob- vious remedy. A scant meal, though, he says, does not seem so scant if brought to an end with a dessert, and he recommends the practice of following lean meals with sweets as an aid to perseverance with a “reducing” diet. However, he advises against attempting to reduce the weight too rapidly. ‘‘A loss of three to six pounds a month,” he says, “when continued sufficiently long, obvi- ously will bring the weight to any desired figure.” —) Radio Storm Warnings GTORM warnings for ships sailing the northern seas shortly will be available from four radio stations to be established in Greenland by the Danish Parliament. One of these will be erected on the eastern coast, the others on the western coast. The eastern station, at Angmagsalik, will be especially useful for meteorological observations, because of its location in the path of storms that sweep the coast.

Page 48

POPULAR SCIENCE MONTHLY

Money Cleansed by a Washing Machine HE term “‘filthy lucre’’ has been banned from the English language as far as a certain Los Angeles hotel is concerned, by the in- stallation of a coin-washing machine in which all money received by the hostelry is cleansed before being re- turned to the guests in the form of change. A rule is in effect in this particular hotel that no money that has not been washed and made sanitary and new in appearance is to be given out by cashiers, wait- ers, and other employees to

the hotel guests. How the used coins are cleaned in the hotel washing machine Compact Stereopticon Uses Rolls of Film NUSUALLY compact and easy to operate is a new type of still-picture projector that uses miniature views on

The new stereopticon, showing film rolls

Small Hand Tiller Useful for the Home Garden OR breaking up clods of earth and smoothing the newly dug garden surface, a new garden hand tool, known as a tiller, has been invented. It should be used with a hammering and spreading action. The pointed front of the tiller can be used for making a furrow for seeding.

This hand tool harrows the soil strips of film similar to motion-picture film, instead of the usual cumbersome glass plates. Each film strip contains from 50 to 500 pictures. The projector is 1014 inches in height and weighs only 414 pounds. It uses a standard incandescent electric globe, with a special resistance cord that makes it adaptable to any electric-light con- nection. By means of a special insulating device the film is protected fron{ the heat of the lamp so that a single picture may remain on the screen for hours. Or, if desired, more than a hundred pictures can be shown in a minute. A Telephone for the Deaf SE of the cheekbone as a conductor to the auditory nerve, coupled with the amplification of speech, is reported to be the secret of a telephone for the deaf that has been put to test use by the Sas- katchewan Government Department of Telephones. It is reported that persons who have been unable to hear for years have been able to hear long-distance calls.

Garden Table Folds like Umbrella AN INGENIOUS | table intended for garden use or for card games in the house, folds into a space about a foot long and three inches wide. The collapsible canvas top of the table folds on the principle of an um- brella, by the sliding of a ring carrying umbrella-like ribs, The longer ribs are straight, to make the top of the table flat. The center post of the table comes in two sections, held in position by a slot in one sec- tion in which pins in the other section engage. Three spreading legs of tubing are attached to an aluminum casting at the foot of the center post. These legs are all the same length, but of three different diameters so that they can fit one inside the other. To a collar on the center post are attached four rings that serve to hold drinking glasses in the event of the table’s being requisitioned for card-playing.

The folding table ready for use Wooden Catboats Built on Concrete Forms N EASTERN manufacturer of cat- boats uses a concrete form on which to assemble them, thus cutting his finish- ing time in half and assuring complete uniformity. Slots in the con- crete are provided for the cross pieces, to which are nailed the centerboard, sides, and bottom boards of the boat. The block not only provides a_ solid working base to hammer __ against, but enables the builder to keep the construction uni- form and_ true without the neces- sity of constant measurement. The . |é concrete form

A workman nailing the bottom boards over the concrete boat form weighs about seven tons. The completed boat is 15 feet long, six feet beam, and is designed to carry a 25-foot mast and 225 square feet of sail.

Bis ~

in s

Page 49

ids able use the pace hree sible folds ring ribs, ight, table table 1d in » sec. the "hree y are inum post. ut of y can yn the _ that 1 the ioned rms npleted and is ind 225 POPULAR SCIENCE MONTHLY 4° New Locomotive Has Diesel Engine HE first electric locomo- tive to use an oil engine of the Diesel type to drive a generator supplying electric power for the driving wheels has been completed by the General Electric Company and the Ingersoll Rand Com- pany. It is designed for switching service and con- sumes from 20 to 26 cents worth of fuel an hour. This is approximately one-third the cost of coal used by an ordi- nary steam switching engine. The 300-horsepower, six- cylinder oil engine is directly connected with a 200-kilo- watt generator. Four electric motors are used, one for each of four axles, providing remarkable flexi- bility. Sufficient fuel for 48 hours’ continu- ous switching service can be carried, and there is no smoke. gine need be operated only when the locomotive is being used. Cooling radiator and exhaust muffler are located above the roof Like an auto, the en- This Machine Cuts, Binds, and Shocks Grain A MACHINE that not only cuts and binds grain, but deposits the bundles in shocks, has been developed for use in ce aes oe Tyztf | . Mon ee § ae or Ry Ya soll > Shocking grain with the new machine grain fields. The shocker is attached to the binder in place of the customary bundle carrier. From the binder the grain is taken by means of an elevator to a basket consist- ing of two separate cone-shaped parts supported at the apex. While one section of the basket is in a vertical position being filled, the other part is carried hori- zontally. In setting the shock, the operator en- gages a clutch that drives the upright member down on the sheaves, and moving the basket backward at the same rate the machine is moving forward, thus placing the butts firmly on the ground in an up- right position. As one portion of the basket is setting the shock, the other turns into position for receiving new grain. The shocker is graintight and is said to save enough loose grain in one year to pay for itself. It has few moving parts and its life is said to be twice that of an ordi- nary binder. Salt Lake Man Has a Back-Yard Gas Plant \\ JHILE drilling a well to obtain a supply of drinking water, a resident on the outskirts of Salt Lake City, Utah, struck instead a well of natural gas. So he connected a 300- The back-yard gas tank that holds a day’s supply of fuel gallon tank with the gas flow and now uses it for heating, lighting, and cooking. The tank, which holds a day’s sup- ply, fills within an hour, and_ the owner now can light and heat his home without the fear that a gas company will shut his meter if he fails to pay his bill. Other residents of the neighbor- hood have drilled seeking similar wells, but thus far without success. Automatic Teller Takes Deposits N AUTOMATIC teller that receives paper money deposits and issues receipts for them is a new device designed to encourage saving among industrial em- ployees. Bills of one-, two-, five-, or ten-dollar denomi- nations are put into their proper slot. Pushing the handle directly beneath the slot produces a correct re- ceipt for the money, which drops into a regulation safe below. The machines are placed in industrial plants, where de- posits may be made at any time. At the close of each workday the cash deposited by all employees is taken from the ma- chine and re-deposited in a_ near-by bank. There each employee is given credit for the amount of his deposits when he shows his receipts. The device is said to bring in many new savings accounts and increase deposits greatly. Making a deposit in the machine Bathing-Cap with Goggles Designed for Divers pok use by swimmers who wear glasses, and to permit a diver to see under water and still keep the water from his eyes, ears, and nose, an elastic rubber bathing-cap with goggles and coverings for the nose and ears has been in- vented by A. G. Johnson, of Wash- ington, D. C. The cap is so constructed that it prevents the en- trance of water, yet allows’ the wearer to breathe freely through the mouth and _ talk without removing the headpiece. Novel bathing-cap

Page 50

POPULAR SCIENCE MONTHLY NOVEL model of a helicopter air- plane, which the inventor claims will carry four times the weight of present types with one quarter of the power, has been patterned on some of the mechanical principles used by birds in flight. The upper and lower wings slope forward until Bird Is Model for Airplane Helicopter they meet in cleaves the air. By opening the V-shaped wings and slowing down the motor, the inventor, Dr. H. T. Randle, of Lawrence, Kan., says the machine can land on any flat- roofed building. a horizontal edge that Ornamental Lighting Posts Reinforced by Tin Cans HE driveways and walks of San Antonio, Texas, are literally lined with tin cans, but not so that one may notice; for the cans are embodied in the electric-light posts. Park Commissioner Ray Lambert orig- inated the ingenious method of utilizing much of the city’s waste tin-can output by using them for reinforcing ornamental concrete posts, as shown in the illustra- tion. Conduits through the center of the posts carry the necessary wiring. The addition of a globe at the top completes an economical and ornamental lamp-post. Pigeons in Flight Whistle Concerts in the Sky fre of the queerest orchestras in the world plays music up in the sky. The players are members of a flock of pigeons, carrying various kinds of light air whistles attached to their tails by fine wires. The originators of this unusual idea are the Chinese. Flocks of the birds carrying musical attachments are sent through the air to provide a unique and melodious aerial concert. The musical instruments used are of two different types—bam- boo tubes, and gourds with tubes attached. They are lacquered in various colors and fitted with mouthpieces that are oper- ated by the rapid pas- sage of the bird through the air. These odd whistles made by the Chi- nese from bamboo tubes and gourds are attached to the tails of pigeons by fine wires, as shown above. The swift flight of the birds through the air blows the whistles, producing a strange concert in the sky Giant Lobsters Caught off the Jersey Coast WO of the largest lobsters ever caught were taken recently trom their deep- sea haunts and placed on exhibition in the New York Museum of Natural His- tory. The largest specimen weighed 34 pounds, was nearly three feet long, and was estimated to ordinary fish trap that they had been robbing. When engaging in formidable combat lobsters are endowed with the ability to leave one or more claws in tight grasp of the enemy in order to escape. The lost members soon grow out again. be 50 years old. It carried many scars on its body from fierce marine com- bats. The smaller one weighed 28 pounds. The haunts of these two subma- rine marauders were off the High- lands of New Jer- sey, where their enormous strength and size enabled them to destroy and rob traps that were too small to catch them. They were finally brought to the sur- face clinging to the outside of an ae & The two great lobsters compared in size with a six-year-old boy Dut T H { tamie a cle sister looke Ur re Ancie the d earlie Tw diggi by tk of the excal with last | towe! at ak the trac buil /

Page 51

tle n the sky, ck of light y fine idea birds sent P and re of ist been ymbat ity to isp of e lost

POPULAR SCIENCE MONTHLY

Duplicate of the Tower of Babel Unearthed HE remains of the great tower of Ur of the Chaldees in lower Mesopo- tamia recently has been unearthed, giving a clear idea of what this ziggurat and its sister monument, the Tower of Babel, looked like when they were built. The Ur remains are more than 4000 years old. Ancient ruins in the vicinity go back to the dawn of history, and are among the earliest buildings known. Two hundred natives were engaged in digging, the work being carried on jointly by the British Museum and the Museum of the University of Pennsylvania. Earlier excavations brought forth clay cylinders with inscriptions in which Nabonides, the last king of Babylon, told of finishing the tower, left unfinished by two kings of Ur, at about 2300 B.c. The tower is solid throughout, with crude bricks inside covered with a facing of baked bricks laid in mortar. Reed mats dipped in pitch were laid between + the bricks. Three sides of the tower are perpendicular. On the fourth huge stairs lead to the summit. As each brick bears

MINIATURE working model of a motorized hook and ladder, filed entirely by hand out of brass, recently was constructed by a fire captain in the Jersey City, N. J., fire department. It

Excavated ruins of the great tower of Ur, showing stairways leading to the summit the royal stamp, it is a simple matter to trace which kings had taken part in the building. . This is believed to have been one of many towers supposed to be imitations of the hills where the Sumerians worshipped their gods before they settled in the Tigris and Euphrates valleys. Three-Wheel Fire-Truck for Small Towns NEW German fire-engine combining a hose cart and a small hook and ladder has only three wheels, one in front and two at the rear. A gasoline motor supplies the motive power. There is seat- ing space for three men. The apparatus was turned out by 4 the Krupp works. * It was designed es- 1 pecially for use in k small towns and villages where é\ ; elaborate and ex- pensive equipment is unnecessary. Since two fire-en- gines are combined in one, the cost of fire protection for | small communities is practically cut in half. The tricycle ma- chine is said to be remarkably speedy a Se allt and easy to oper- The three-wheel truck combines hose cart and hook and ladder ate.

SSSR, See gF NN wd SSE

gE acer (< ~ = : AS = OS ae x CALE Tt | th ~

Miniature Fire-Engine Filed from Brass was modeled after the first piece of mocor equipment installed in the department. Practically every part of the real ma- chine is embodied in the miniature, the only difference being that an electric motor is used instead of the gasoline en- gine employed in the original.

Smallest New York Store only Two Feet Wide HAT is said to be the smallest store in New York City, if not in the world, recently was opened for business by a locksmith, machinist, and electrician. The width of the shop is 24 inches. It is so small that customers cannot enter, and business is transacted through the window in the front door. The owner leaves by a door at the side that forms one wall of his unique estab- lishment.

MADE WHILE} You Warr

SNAQNOV ELD:

The smallest store open for business

Cow Bones for Chinese Game HREE carloads of shinbones from cows slaughtered at a Chicago pack- ing plant recently were shipped to China for use in manufacturing the popular tile game.

Page 52

POPULAR SCIENCE MONTHLY

eg en i We es

Cutting Steel with a Torch under Water At A scientific exposition in Paris re- cently was demonstrated a method for cutting steel under water with a torch. To the usual oxyacetylene torch is added a supplementary system of compressed air. This blows the water away from the mouth of the torch sufficiently to permit the oxyacetylene gas and its electric are to funetion as usual. The diver carries the torch down with him on his descent, one end of its supply tubes being connected with a _ barge above. When the torch is removed from the cutting surface, the flame is cut off. The effectiveness of the method de- pends on the depth of water and the thickness of the metal plates to be cut. As the depth increases, the pressure of compressed air must be increased greatly to maintain the force of the cutting flame. New Stethophone “Broadcasts” Heartbeats HROUGH the invention of a new human “broadcast’”’ electric stethophone, the heartbeat now may be through a great number of instruments to listeners several feet away from the sub- ject. The new machine amplifies the

sound of the heartbeat three times. The _ electrical apparatus that does the amplify- ing is moved on a wheeled table sim- ilar to a tea-table. It was demon- strated not long ago before 500 doc- tors attending the convention of the American Medical Association in Chi- cago, and promises soon to become a regular part of hos- pital fittings.

Above: Five hundred physicians listening to amplified heartbeats. Left: A child listening to his own heartbeats The Spectrum in Industry HE spectrum, once used only by astronomers, now is beginning to play an important part in American in- dustry. In the development of a method of spectral analysis of metals—a method perfected by the U. S. Bureau of Stan- dards—an increasing number of industries are finding a valuable new aid in detecting impurities in metal products. This system has been used with success in determining causes of boiler explosions, and in preparing purity standards of vanadium steel, platin:1m, rhodium, iri- dium, and palladium. Subway Coin Machine Makes Change Automatically ties of the latest devices to expedir, the movement of crowds in trang. portation is an automatic coin-changing machine introduced by a New York Cit, rapid transit company. Without the aig of an attendant, it is said to change dimes quarters, and half dollars into nickels more rapidly than any human change. maker could do it. The photograph below shows Fran Hedley, president of the transit company. demonstrating one of the machines which, he says, eventually will be installed in 304 subway stations in which about 120 attendants now are employed. Simplicity of -operation is one of the valuable features of the machine. At the ‘Auromatic MONEY CHANGING Mat INE! i f INSERT Money HERE

Demonstrating the automatic coin changer top are three slots, marked 10, 25, and 30 cents. Above these is the instruction: “Insert money here.’’ When the specified coin is deposited, the correct change for it is deposited automatically in a corre sponding receptacle below. Beneath each slot is a lens that mag- nifies the deposited coin four times, so that the coin may be seen both by passen- gers and by the attending guard. Thisis to aid in the detection of slugs or counter- feit coins.

An Automatic Nailer REATER speed and convenience i! nailing roofing is provided by a de vice that automatically places nails up to 114 inches long in position to be driven in. The machine consists of an iron frame holding a nail box from which the nails are fed down an inclined carrier. A catch holds each nail in position for hammering.

hs a Laying roofing with the nail machine

Mir : b tunne¢ River Lam] miniz comp sentil An shar} After mode set ir each direc degre glass prev the |

Page 53

akes ly pedite trans. Anging < City he aid dimes, lickels ange. Frank \pany, Which. in 300 120) of the At the U. & U. hanger and 50 iction: ecified e for it corre. r mag- 1eS, $0 yassen- T his is yunter- |i nee il oa de ; up to ven in. frame e nails ion for

Miniature Tunnel Built for Lighting Tests O DETERMINE the most effective way of lighting the twin vehicular tunnels now being built under the Hudson River, engineers of the Westinghouse Lamp Company recently constructed a miniature model of a tunnel section, complete to the tiny automobiles repre- senting vehicular traffic. Ample light without either glare or sharp shadows was the desired goal. After numerous experiments with the model, specially designed reflectors were set in iron boxes embedded in the wall on each side near the ceiling, the light being directed downward at an angle of 20 degrees. With the addition of diffusing glass covering the reflector mouth to prevent glare, this arrangement solved the problem. Two thousand of these special lighting units will be used, spaced at 20-foot inter- vals. Illumination three times greater than that on the average city street at night is said to have been achieved. THe model is on a scale of one inch to one foot. It represents a tunnel section 120 feet long, being itself 10 feet long and 29 inches in diameter. The exact intensity of light to be used in the real tunnels is used in it. Signs around the mouth of the model explain the engineering fea- POPULAR SCIENCE MONTHLY — Pw UE of EXHAUST PORTS _<@<@ioom , TELEPHONE CABLES 9 \@ FIRE =| EXTINGUISHER [i WATER SUPPLY Zoue PIPE

<— EXHAUST PS AIR DUCT eR | my SIDEWALK % se fry: ence i ‘SEES

FRESH AIR DUCT

Cross-section of model vehicular tunnel, showing lighting, ventilating, and conduit systems tures of the tube, chief of which is the ventilating system. This, designed to meet the special difficulty of exhaust gas, supplies fresh air through flues from a large duct be- neath the roadway and removes vitiated air through ports to an equally large duct above the roadway. Each of the twin tunnels, one for east and one for west traffic, will have room for two parallel lines of automobiles, the roadway being 20 feet wide. One side will be for slower vehicles, like trucks. Each tunnel will be 134 miles long. They are expected to be ready for use early in 1926.

This Simple Pocket Catch Safeguards Your Watch A CATCH with two tiny metal fingers secreted at the top of the trousers watch pocket has been devised to guard timepieces from slipping out and dropping to the floor when the trousers are hung upside down. _ Aneatly concealed spring base plate is inserted on the inner side of the watch pocket. Spring fingers run along the top of the pocket and meet at the center, closing over the watch chain. When the watch is in place, it is securely held in an upright position so that the trousers may be shaken and folded without any danger that the watch will fly out and crash to the floor. When the watch is to be removed, Pressure on the inner spring separates the fingers far enough to permit the chain to pass through. This can be done quickly, with a simple movement of the fingers. Ornamental Telescope BRONZE reflecting telescope per- manently mounted for home use and possessing beauty of design that har- monizes perfectly with a garden or lawn setting, now is available for persons who have made or would like to make the study of the stars their hobby. The instrument also can serve as a sun clock. The conventional telescope design must be taken down and carried indoors when the evening’s observa- tions are done. When it is brought out again, it must be set up on its tripod and carefully adjusted. The new garden telescope, on the other hand, is a permanent fixture on the lawn, always ready for use. The tube of the usual telescope serves solely to hold the prism and eyepiece rigidly in their proper relation to the concave mirror that catches the light. In the new

design, the mirror is on a decorated hol- low hemisphere, lead- filled for counterpois- ing. A curved, solid arm carrying the prism and eyepiece, ascends from the hemisphere. This swings freely on trun- nions. Thus the re- flected light passes through free air to the prism. An addi- tional eyepiece allows observation by two persons simultane- ously. The telescope is swung between its supports within a hol-

for Lawn or Garden low member resembling an upturned bell. Part of this bell is cut away, permitting the arm to swing so that.any part of the heavens can be observed.

Above is shown the artistic new reflecting telescope permanently mounted on its orna- mental pedestal in the garden. At the left is a close-up view of the in- strument, showing the arrangement of the con- cave silvered glass mir- ror, the right-angled prism, and eyepiece

Page 54

POPULAR SCIENCE MONTHLY ? Ca Seva: FA | M205 ——— a HE increased use of gasoline motor- cars for passenger service has created a need for turntables at many points where there are no shops or facilities for turning cars. To meet this need a special turntable has been devised that needs no pit under ordinary conditions, and that may be moved easily whenever desired. This effects a reduction in cost and installation. Workmen Walk across ONSTRUCTION of America’s great- est suspension bridge—The Bear ~- a. ee omit |e Surface Focatable for Railway Motor-(Cars Ti The equipment consists of a circular foundation rail on which rides the turning section supporting the tracks. The dis- tance from the top to bottom rail is only 211¢ inches. The outer wheels on which the table runs are equipped with roller bearings. The table may be installed at any con- venient point at small expense, it is claimed, and can be moved readily. Great Hudson Bridge across the river between Poughkeepsie and New York City. Its total length will Mountain bridge across the Hudson— has progressed to a point where workmen actu- ally have walked from shore to shore across two tem- porary suspen- sion bridges. This great project will be the first bridge f | j | | | | | j | View of the two temporary spans, showing the great size of the project be 2252 feet, including approaches. on as, mora Building a span above the Hudson Most Powerful Magnet Used for Experimental Work HE most powerful electric magnet in the world, used in connection with wireless research, has been installed in the laboratories of the University of Stras- bourg, in Alsace. It was constructed upon the calculations of M. Weiss. When the magnet is in operation, the strongest man would be unable to pass a steel butcher knife through the air be- tween its two poles. The apparatus is equipped with numer- ous adjustments that adapt it to a wide variety of uses in wireless experimental work, and is mounted on a wheeled truck so that it can be moved from place to place in the laboratories. | The world’s most powerful magnet Hearing the Printed Word eae on a principle similar to that employed in the telephone, a new de- vice for making the printed word audible has been invented in Germany. The secret is said to lie in modifying printer’s ink to make it conductive of electricity in varying degrees. On strips of paper, symbols that are very similar to the Morse dot-and-dash code are printed in this ink. These strips then are used in an electrical apparatus to make and break electric contacts so as to sound a bell or buzzer. Brick Walls Reinforced by Layers of Wire O PREVENT brick houses from “cracking” and to give build- ings added solid- ity, a new system of reinforcing has been introduced. This consists of laying a wire between every sec- ond layer of bricks. As each layer is completed, wire is stretched along the top, and on this is spread the mortar for the next row. Strips of reinforcing wire laid between the rows of bricks Val A them devel grap] ident missi A pictu place cial 1 motc¢ the | mak num ——— y 7a7aM _ Ay

Page 55

ed c t in with | the tras- pon the ISS a be- mer- wide ntal ruck e to ord that w de- dible The \ter’s ty in ; are dash trips ratus SO as Valuable Documents Copied on Film Negatives A MACHINE for copying letters and L% other documents without subjecting them to the scrutiny of outsiders has been developed to give instantaneous photo- graphic records of any letter-size papers, identifying them so as to make them ad- missible as legal evidence. A miniature film negative of motion- picture size is used. Documents are placed under a glass illuminated by spe- cial reflectors. Pressing a button starts a motor that moves a section of film before the lens, exposes it and moves it on to make way for another picture. Any number of pictures thus may be made of Photographing papers with film machine any document. The miniature negatives then are developed and enlarged. Each document is positively identified by means of a special arrangement at the top of the glass that holds the paper being copied. This consists of three bands of fragmentary geometrical designs and a serial number, the bands and serial num- ber automatically changing with the changing of documents. The bands move in opposite directions at different rates so that each document copied has photographed with it a record of the serial number and a different de- sign, making counterfeiting impossible. POPULAR SCIENCE MONTHLY World’s Largest Belt Weighs Seven Tons "TBE largest belt in the world was made recently for a concern in New Jersey. The belt is 1550 feet long, 36 inches wide, weighs seven tons, and cost $1000 a ton. It took 12 workmen more than three hours to wind it on a reel more than nine feet in diameter. The illustration shows the belt wound on the reel. A Push Releases Automatic Door Check NEW .automatic door check is so designed that one push on an open door fastens it and a second push in the same direction releases it. At the base of the door is fastened a hook connected with a spring plunger or bolt, which extends slightly in front of the hook. A base plate screwed into the floor contains a_ slot be Fs to catch The floor plate, hook and bolt Road-Finishing Machine Driven by Two Men HAND-OPERATED road-tamping and -finishing machine, said to finish concrete roads as satisfactorily as motor- driven machines, has been developed for use by contractors. The machine moves on two tracks that constitute the form for the concrete. A shaft ex- tending across the top of the machine Bom i, is turned by two men, one on each side of the road. Through the ac- tion of a cam, the tamper is given both vertical and lateral motion, insuring a perfect crown. Two strike-offs, a tam- per, and wood-fin- ishing belt, passing over the plastic mass leave the surfacing smooth and _ with the desired crown The machine runs on tracks that serve as the form to the road. SPRING BOLT / the hook and hold the door open. When it is de- sired to close the door, a_ second push compresses the plunger and allows the hook to move into a chan- nel of the base plate. This disen- gages the hook so that the door may be closed again. While designed primarily for use in railroad cars, the device is adaptable also to garages. ow) DOOR PART LOCKING INTO FLOOR PART oo saa Upper diagram shows Sa mechanism of locking, and lower diagram, that NU of disengaging door check

Page 56

56 POPULAR SCIENCE MONTHLY Shall We Add a Thirteenth Month? Radical New Calendar Advocated to Simplify Calculations N JANUARY 1, 1928, it is possible O that the world may begin to live by an entirely new calendar, a calendar in which a year will consist of 13 equal months of four weeks each, and in which the same date of every month always will fall on the same day of the week. Such a revolutionary revision not only is being considered by a special committee of the League of Nations, but also has been urged in recent resolutions passed by the American Meteorological Society at Washington, D. C., where it was actively supported by Dr. C. F. Mar- By Truman Stevens calendar year is concerned, probably is as nearly perfect as possible. Yet while it is the standard calendar of today, the result of its method of dividing the year into months of various lengths is that no two consecutive months or years begin with the same day of the week. For this reason a calendar dividing the year into equal, corresponding parts has been sought. A solution in the form of the 13-month calendar was worked out not long ago by a French engineer. It is called the ‘‘Dela- contain the same number of workdays, the same number of days of rest. |t is a modification of this plan that is being advocated for 1928. XPONENTS of the plan say it would be of great benefit to labor. All cal- culations of income and expenses would be unified. As it is now, the laborer who is paid a fixed wage a month works only 24 days in February while in other months he works 25 or 26. Under the new calen- dar the working man would receive the same monthly wage for the same amount of work. The annual WINTER SOLSTICE,CORRES PON DING 34 5 67 8 9 10 I 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 TIW|TIFIS MITIWITIFIS MITIWITIFIS vin, chief of the TO DEC. 22,PRESENT CALENDAR United States MO Weather Bureau. He 1MO M declares it would greatly simplify the collection and study of weather data. The year 1928 is advocated as the most favorable time to start the new calendar, according to Doctor Marvin, since that year be- gins on Sunday. Consequently the SPRING first day of each of the 13 months would fall on Sunday. 2M0. WINTER EFORM of the calendar is not such a new thing as it may seem. It is as old as the history of SUMMER man. For centuries efforts have been made to improve the calendar so that it would coincide with the astronomi- cal year—that is, the time required by the earth to com- plete its journey about the sun—and ku AUTUMN TIWITILF IS MITIWITIFIS CHRISTMAS DAY (PRESENT) JANUARY 15ST (PRESENT) MITIWITJFIS LINCOLN'S BIRTHDAY (PRESFN7) MiT MITIWITIFIS SPRING MT MiITIWITIFIS EXTRA DAY OUTSIDE OF DAY AND WEEK TWO OF THESE FOR LEAP YEAR wages would not be smaller, because the men would be paid MIT IWITIF for 13 months in stead of 12 and the TT aggregate would be the same. From the point of m{T view of religious ob- servance the new calendar would offer many advantages. The movable feasts, Easter, Ascension, Pentecost, always would fall on fixed days, and the in- movable holidays always would fall on the same day of the week. For example, as- suming that the first day of the year (cor- responding to the present December 22) would be Sun- day, our Fourth of July would fall every year on Friday, the twenty-seventh day of the — seventh month. The present Christmas Day would fall on Wed- nesday, the fourth day of the _ first MITIWITIFIS so afford complete unity between man’s and nature’s reckon- ing of time. The ancients had many calendars, all of which were inac- curate and no two of which were alike. To correct the resulting confusion, Julius Caesar initiated an important reform— the Julian calendar. This gave the civil year exactly 365 days, or nearly a quarter of a day less than the astronomical year, which is 365 days, 5 hours, 48 minutes, and 45.9 seconds. This discrepancy was corrected every four years by adding an extra day to February, creating the bis- sextile or leap year. But over an extended period even the Julian calendar accumulated discrepan- cies, which in the time of Pope Gregory had reached the extent of 10 days. Radi- cal corrections resulted in the Gregorian calendar which, so far as length of the The Delaporte calendar, showing how the year, beginning at the winter solstice, would be divided into 13 equal months of four weeks each, with an extra day for New Year. The porte calendar,” after the name of the in- ventor. For the purpose of equal division, Delaporte would take a year of 364 days, the extra 365th day becoming New Year’s Day. Then he proposes to divide the year into 13 months instead of 12, each month to be composed of four seven-day weeks, or 28 days. An extra day would be added in leap year. Since 13 months cannot be divided ex- actly into four equal parts, Delaporte would divide the 364-day year into four seasons, each containing 13 weeks. The first day of the year would be fixed at the winter solstice—the shortest day, cor- responding to December 22 of our present calendar. Every month in every season would year also is divided into four equal seasons of 13 weeks. Notice how the same date of every month falls on the same day of the week. The positions of present holidays are indicated month, and the pres- ent New Year’s Day on Wednesday, the eleventh day of the first month. The new calendar undoubtedly offers many advantages—an exact solution of a world-old problem. But will the world ever accede to the great change that would be necessary to conform to it? The committee of the League of Na- tions that now is considering the calendar reform, includes representatives of the world’s great religious, scientific, and in- dustrial organizations. America’s representative on the com- mittee is Willis H. Booth, of New York, president of the International Chamber of Commerce. The conferences are eX- pected to result in definite reeommenda- tions to the League. Action by the League would be followed by legislative proposals to the various governments. ps Sad

Page 57

?f Applied Science in the Household lays, It eing ‘ould Cal- ould who only ynths alen- > the ount nual ot be e the paid S in d the ld be int of 1S Ob- new _ Offer fages. easts, nsion, lways fixed > im- ‘idays all on of the e, ase e first ' (cor- » the >mber Sun- ‘th of every y, the h day venth resent Day Wed- ‘ourth first > pres- s Day vy the of the offers n of a world that x4 { Na- lendar yf the nd in- - com- York, amber re eXx- ,enda- y the lative The vegetable slicer below con- sists of a frame into which may be inserted a variety of cut- ting plates by opening one side of the frame POPULAR SCIENCE MONTHLY 57 A vacuum cleaner with a suction handle, as well as a suction base,- can be used for cleaning places other- wise inaccessible, such as bookcases and chests. It has a self-adjusting nozzle This neat kitchen coalbox has at its base a movable -, Chute that drops out a small } quantity of coal where it may be reached easily with a shovel An aluminum box made in two sections with a remov- able slotted plate in the center forms an effective egg-beater. The egg is broken into one section, the loose plate is laid in posi- tion, and the other section of the box attached. Shak- ing the box beats the egg % This invisible tea-strainer is held firmly inside the pot by a spring band of stainless steel to which it is attached. In the pot the strainer covers the base of the spout,and is held by the spring With no long spout in which old leaves may stick and spoil the flavor of new tea, this porcelain teapot has instead a special lid in which are two small slits that strain all the tea as it is poured through the small spout. The cover is removable to aid in washing its. This serviceable jar-opener consists of a strap of spring steel, notched at the side to engage a lever handle, and with lugs in the center to grip the cover tightly and so unscrew it Any oven may be converted into an elec- tric oven by this newly designed heater, which is quickly attached to the oven wall by a single screw, and which plugs into an ordinary electric socket. The heater may be used also for fireless cookers, clothes- driers, bed-warmers, and water-heaters

Page 58

Swinging Pendulum Warns at Grade Crossing RESNO, Calif., has augmented the usual railway grade-crossing sign by the installation of an electric warning post in the center of the street. A pendulum hung from a frame at the top of the post, swings continuously, calling attention to motorists of the presence of railway tracks. On the swinging pendulum is a “Stop” sign for daytime warning, and a red light that flashes a danger signal at night. The supporting column is well lighted to prevent the possibility of a motor- ear’s colliding with it. POPULAR SCIENCE MONTHLY SIX-CYLINDER motorcycle con- sisting of two separate three-cylinder engines, one on each side of the frame, is the unusual invention of a British motorcycle enthusiast. The engines are four cycle and together are rated at 16 horsepower. Each have magneto and carburetor, and are cooled by vertical fans. Odd Motorcycle Is Driven by Twin Engines Wi Mechanical lubrication with sight feed HI¢ and chain transmission with three speeds joy are used. There are shock absorbers op used ca the front forks, two gasoline tanks, speed. value fi ometer, clock, a gradient meter and gago. ae line gage. A small tank under the seat establis carries reserve fuel. Brakes are installed ratory } on front and rear wheels. Autom\ Service Station Has O PREVENT loss of tools or other personal belongings from cars left for repairs, a Brooklyn, N. Y., service station we ride over concrete roads today. ing the ; membe This strange motorcycie is driven by two three-cylinder engines, one on each side to test it 7 astleib cds every ¢ Safe-Deposit Boxes Water Vaporizer Designed ci has provided a series of large metal to Eliminate Carbon ; The boxes, or lockers, into which articles A SIMPLE water-vapor device cor : hese left in the machine are placed. The necting the radiator and intake mani- page aie 4 ea the fold is designed to prevent carbon for- Ther key and an identil- mation in automobile cylinders and to fication check. Samia: nh cade ak : E pert el The lockers are T per ppalesineren starting Pci ag al It consists of a connection to the water bing mc asad ali : The discharge pipe near the radiator, an auto- | perforn oh ei cai a matic valve installed in the gasoline in- HP are cor tl as Mahe take manifold, above the butterfly valve, HM engine the cars Nkewlse and a length of small copper tubing joir- heck are checked and =; . . eneck t stored on shelves ing the two fittings. : cut-In i pre 1 k - Through four small holes in the body An und above the 10ckers of the automatic valve, air is mixed with tected to prevent any , . possibility of their becoming soiled GPA and stained by me grease and oil while - in > ; and W Articles from the car mechanics wind S The en are stored in safe-de- working on the . posit boxes as shown automobile. examin is est and the Sah its futy The Origin of Paved Roads system UR modern dustless concrete auto d In roads may be said to have originated quip in a dusty limestone highway of England. gi Just 100 years ago, Joseph Aspdin, a On th mason of Leeds, England, discovered that ta if the dust of limestone roads was mixed Arrows indicate radiator-manifold connection under - with clay and burned at a high tempera- — ture, the resulting mass when ground’ the water in order to vaporize it. The ‘ella would produce a material that hardened water is taken from the circulating sy o_o : : : : : and th when mixed with water. tem so that no extra tank is necessary, M - This hard, stonelike substance looked the amount being regulated automatically Pe: #4 like building stone quarried at Portland, by the speed of the engine. It is shut off ral England, so he called it Portland cement. automatically when the engine stops. t ‘ls Because he mixed brains with his mortar, The distinctive feature about the a device is its simplicity.

Page 59

1es§ feed, peeds rs on peed- £aso- Seat alled ned l con- mani- 1 for- nd to water auto- ne in- valve, r join- body 1 with section The g sys assary, tically hut off dS ' pert electricians. | ing motor is turning the engine. t the HICAGO motorists, at least, now en- joy the prospect of being able to buy ysed cars With a reliable certificate of full value for their money. This has been made possible by the establishment of a huge new testing labo- ratory in Chicago, under control of the Automobile Trade Association, compris- Worth of Used Cars Tested in Laboratory POPULAR SCIENCE MONTHLY factors are determined accurately by chemical tests. The final step is a careful examination for defects in the chassis, springs, or mechanical parts. Should any of the parts have heated under the loads, this examination reveals it. If the car stands up under all the probing, the laboratory issues its ©.K. ing the used-car dealers of Chicago in its membership. The laboratory is prepared to test about 100 cars a day, and to give every car a combing over that will leave absolutely nothing uncovered in the way of defect that may harass the purchaser. The first step in the tests is a sort of “registration” of the make of the car, type, and model, and the specifications a § car of its age and type should meet. Then the car falls into the hands of ex- First, the battery and starting motor are tested while the start- The performances of the battery and motor are compared with standards. With the engine running, the electricians then check the generator output as well as the cut-in and cut-out points of the regulator. An unduly high or low charging rate is de- tected. PARK plugs and ignition are tested by means of a grounding gap. This test tells also whether the plugs are set properly and whether they are firing as they should. The engine then is stopped while a careful examination is made of the breaker points and the ignition unit. If the car ‘‘passes,”’ its future owner may be sure the ignition system will function properly. In practice, a test of all electrical | ‘quipment is completed in less than 15 minutes. The car then moves along to the Wasson horsepower-testing stands. On these stands the automobile runs under its own power with its rear wheels turning on friction drums. A pony brake, operating on the -drums, determines horsepower delivered at different speeds and the twisting effort, or torque. Meanwhile examinations of fuel con- ‘umption and piston leakage are made. Also a sample of the cylinder oil is drawn ‘tom the engine base and the amount of and other Water, dilution, chemical Testing used cars in the Chicago laboratory to assure protection to the purchasers .Thereafter any buyer may be sure that when he takes the car on the open road, it is likely to give satisfactory service. Novel Car on Stilts Offers a Bird’s-Eye View T°? ATTAIN the utmost in novelty motoring and incidentally a bird’s- eye view of the scenery, a Los Angeles man put his car on stilts by raising the body several feet above the chassis and extending the operating levers the neces- sary distance. Now he is able literally to look down on every one. While the appearance of the car is grotesque, it is operated the same as any other automobile. Its chief drawback, of course, is the long climb from the ground. One Man Runs Combined Tractor and Grader PERATED by one man, a new combined grader and _ Fordson tractor now coming into use on hundreds of roads throughout the country, is said to cut the cost of roadmaking and main- tenance enormously. No teams or extra electric steel castings and heavy steel sections. The grader can be assembled, it is claimed; within an hour. No holes need be drilled. Disassembly is said to be at least as easy, permitting the tractor to be used readily for other purposes when drivers are required, and the machine works rapidly on the roughest surfaces. In winter it functions equally well as a snow remover. The grader blade can be raised quickly and lowered or swung to either side, at any angle. The tractor clutch and gears are manipulated from the operator’s plat- form by hand and foot levers, giving the ease. of automobile control. The grader is constructed largely of needed for them. Two quarts of oil and 15 gallons of gasoline, it is claimed, will oper- ate the grader stead- ily through an eight-hour day. The combination tractor serves as a road-grader (left) or a snow-remover (be- low), according to the time of year

Page 60

60 POPULAR SCIENCE MONTHLY Maughan Proves U. S. Airway Possibilities SIDE from its scientific andy , | commercial, | significance — dem- onstrating as it did the marvelous capa- bilities of the mod- ern airplane, and possibly speeding the arrival of the time when passen- gers and freight will be carried through the air as readily as they now are trans- ported by railway, ship, and motor-car -——the recent feat of Lieut. Russell L. Maughan, U.S.A.,in flying from New York to San Fran- cisco between day- light and_ dark, stands forth as one of the most daring exploits of all time. No glory is taken from Maughan’s achievement by the fact that more than a year ago Lieuts. J. A. Macready and O. G. Kelly accomplished an Atlantjc-to- Lieutenant Maughan and his plane at the end of his transcontinental flight Pacific flight without descending from the air—still the world’s record non-stop flight. On the contrary, the conditions under which the flights were accomplished Wind Tunnel Used in School of Aviation OR scientific experiment in the design and construction of airplanes, and for the study of wind pressure and velocity in relation to the lift and resistance of airplane wings, a wind tunnel recently has been added to the mechanical equipment of the aerodynamics department of New York University. dards, and Prof. Alexander Klemin, are in charge of the work being conducted with the new machine, which is the first of its kind. It is expected to aid greatly in giving students of the university a grasp of the fundamental principles on which the mechanics of aviation are based. In the tunnel is placed a model airplane wing about three feet long, while a pro- a peller driven by an electric motor sweeps the wind through the tube at veloci- ties up to 70 miles an hour. The pressure and velocity of the wind' are registered by an instrument known as a wind balance, and the effects of the wind variations on the model airplane wing are observed by the experimenters. Professor Collins P. Bliss, head of the Department of Mechanical Engineering of New York University and Director of the Popular Science Institute of Stan- 2a ey s é SS s ‘& bh toe a5, bn ee ae ’ — Pr Re Above: The wind tunnel at New York University. Pro- fessor Collins P. Bliss, head of the Department of Mechan- ical Engineering, and Director of the Popular Science Insti- tute of Standards, is seen at the right. Left: The instru- ment that registers velocity and pressure in the tunnel were so decidedly different tha; Maughan’s feat be. comes all the more remarkable. Maughan’s _ ajr. plane was a Curtiss one-seat pursuit plane, designed to remain in the air fo; only about three hours. It was ex. actly like 25 othe planes now being constructed for the army air service. No change was made in body or mechanism in prep- aration for the coast-to-coast flight, beyond providing additional gasoline storage space. The plane used by Macready and Kelly was the army trans. port type—a large, comparatively slow craft. It was balanced and operated by automatic devices, making it unnecessary for the pilots to do more than steer it. Maughan, besides being alone, was forced to exercise constant vigilance. And so for the 21 hours, 47 minutes, and 45 ‘seconds that elapsed between his take-off at Mitchel Field, N. Y., and the time of his landing in San Francisco, Maughan was constantly on the job. ORE than that, he was sick for vir 1 tually every second of the 18 hours, 30 minutes, and 45 seconds that made up his actual flying time. Speeding through the rarefied upper atmosphere at an aver- age rate of 154 miles an hour for 2890 miles, Maughan was afflicted with a vio- lent nausea, an enervating, discouraging illness that aviators describe as being akin toseasickness. The only respite Maughan had from his illness was during the three hours and 17 minutes that he spent on the ground while his gasoline was being re plenished and minor repairs were being made on his machine. Despite this though, he persevered, bettering the time of Macready and Kelly by five hours an¢ 36 minutes, winning all the laurels that rightfully belong to the first man to fly across the American continent alone and unaided in a single day. Maughan’s flight, however, was 10 mere feat of physical endurance. It was? test arranged by the army air service the mobility of this country’s air fleet. And from a military standpoint. Maughan’s personal glory is secondary t the proof he gave that in time of necessit} the air forces of the United Siates can be mobilized in any section within a day. And while army officers were dwelling on this thought, the Post-Office Depart ment inaugurated its coast-to-coast 4! mail service that takes letters from Ne York to San Francisco in 34 hours at® back in 32. 4 These two epochal events, occurtilt within a few days of each other, sure: point the way to the tremendous pos bilities of aviation in the next few yea IR] ju Africa, two-da For ment h the ne capabl journe: equato L ry) Macre: aerial tures ( nearly ment 3000 yn it the mighty In | camer: ground Steven T AS by M; Comm; of Unit machi in the

Page 61

Tr vit- n0urs, de up rough aver- 2850 a Vi0- raging g akin ughan three on the ng re- being this, e time rs and s that to fly alone ‘as no L was a vice of ; fleet. {point, lary t cessity can be lay. welling Jepart- ast al! m Net irs ane curring surely ; possi y yeals. POPULAR SCIENCE MONTHLY i ee * IRPLANES are about to fly over the jungles in the Belgian Kongo, Africa, cutting a 45-day land journey to a two-day jaunt through the air. For three. years the Belgian govern- ment has been conducting tests to perfect the new type of plane shown above, capable of making the rigorous 1200-mile journey that virtually lies along the equator. The extreme climatic condi- Sturdy Triple-Engine Planes to Fly across Kongo Jungles tions cause a severe strain on the structure of planes in this area and landing-fields along the route are practically non- existent. The new type plane therefore will be equipped with three engines, a 350-horse- power Rolls-Royce in the nose of the fuselage, and two 230-horsepower engines on the wings. gines fail, the plane still can hold the air Should any one of the en- and reach its destination. engine alone is capable of flying the ship if it is not loaded with its full complement of freight. The front The wing span of the machine is 75 feet; the length of plane, 60 feet, and the height 17 feet. - Accommodations for 10 passengers and 1000 pounds of luggage will be provided and the flying speed will be more than 100 miles an hour. This Camera Takes Photos at Record Height LONG-DISTANCE aerial camera of the type with which Lieut. John A. Macready, test pilot, and A. W. Stevens, aerial photographer, recently took pic- tures of Dayton, Ohio, from a height of nearly six miles, will be part of the equip- ment of an expedition scheduled to go 3000 miles up the Amazon River. With it the first aerial photographs of the mighty river will be made. In photographing Dayton, the giant camera registered clearly objects on the ground invisible to the airmen. Captain ‘tevens is shown above with the camera. The Mirage—A New A NEW peril of long-distance flight ~~ Was revealed in a recent statement by Maj. Frederick L. Martin, who was commander of the round-the-world flight of U hited States Army planes, and whose machine crashed against a mountain peak inthe Aleutian Islands. He ascribed the Dieta SAM’S army fliers recently gave New-Yorkers a thrill when they blotted out the lower end of Manhattan by dropping a smoke screen over that part of the city from airplanes equipped with special chemical apparatus. The aerial demonstration was con- ducted under the direction of the Chem- ical Warfare Service and the Army Air Service to gage the possibility of screening America’s largest city from the attacks of _ anenemy. The smoke screen proved an effective barrier to vision, but was not impene- Smoke Screen Hides New York Skyscrapers , trable to ‘‘enemy airplanes,” which flew through it easily. Varying in color from white to greenish white, the screen was laid down by two tanks under the body of each plane. The tanks contained titanium tetrachloride and carbon dioxide, and both discharged their contents through a common outlet at the tail of the machine. Air contact vaporized the chemical combination, which dropped rapidly. In the test the smoke fell until it struck the water, clung there a moment, then rolled upward, where it gradually thickened. Above: Manhattan skyscrapers almost con- cealed by the smoke screen dropped by air- men. At the right, an army smoke plane Danger to Aviators mishap to a mirage that changed the apparent face of his surroundings. A mirage is a picture in the air caused when light rays carrying an image are bent by variations in the atmosphere’s Such distortion may entirely density. upset a flier’s judgment of distance.

Page 62

POPULAR SCIENCE MONTHLY Motor-Truck Can Drive J Ho through Huge Stack O HUGE are the new smokestacks jp. W stalled on the transpacific liner, City of Los Angeles, that a motor-truck ca, Je! ' drive through one of them with plenty o the ¥ room to spare. pied These huge funnels are part of The | $1,000,000 worth of new equipment fo; an ad the famous steamer that plies betwee, 7 Wi Los Angeles Harbor and Honolulu. possil The diameter of each stack is 17 feet 3 _ inches; the height, 37 feet, and the weight Jae! is 30 tons. i the bi The illustration shows a truck driving cut f through one of the stacks as it lies on its the e side at a Los Angeles shipbuilding plant, ciaeae waiting to be put in place. i wa 62a * Twenty-Foot Trench Forms a Natural Silo N ENTERPRISING farmer at long. The silage was packed to the Tucson, Ariz., put into use an un-_ earth’s surface and covered with two feet usual silo that might be duplicated by of clay—a method that-is said to keep the other farmers. He excavated a trench silage in as good condition as with the about 20 feet wide and deep and 300 feet most elaborate modern silos. Electricity Employed to Make Plowing Easier AN INGENIOUS electrical method for making plowing easier has been invented in England. A large part of the work done in plowing is “‘wasted”’ as friction between the mold- Wigs Made of Glass Hair board and the soil. The idea is to use the H soil moisture to lubricate the moldboard. ook threads of spun glass, such as is T ; By insulating the colter of the plow and used for sparkling tinsel on Christmas a passing a current from it through the soil _ trees, are being made into wigs for women in Ti to the moldboard, the water in the soil is by a newly discovered process, which may ‘ caused to move to the moldboard. set a new style. Roadside Barbecue Feeds Hungry Motorists used for roasting. The originator of the idea is R. W. Wiggins, who is shown 1 the picture, and it is said that motorists are giving him every encouragement. A truck driving through the stack Elec sign e is 58 fo ai dias HE latest idea in barbecuing is a road- side fireplace and grate erected by a Cincinnati man along the Lincoln High- way, where he supplies motor tourists with fresh hot sandwiches or roasts right off the fire. y The meat is placed before the fire on a steel spit that is rotated by a small electric motor connected with it by a belt and pulley. A trough below catches the meat juices. All the Extension Ladder NTEW YORK CITY’S newest fire- 4 fighting equipment consists of a 100- foot extension ladder that folds up on top of the motor-truck that carries it. Mech- anism at the base makes it possible to turn this huge ladder in any desired position and to extend it upward to a height of several stories of a building with extraor- dinary rapidity. operator has to do is to start the motor and dip up the juices from the trough to baste the meat. Gas or charcoal is the fvel The roadside barbecue, showing electric motor that turns the spit BS

Page 63

House Cut in Half to Make og ae ‘ Room for Building THEN a power company in Man- cks in- \ / chester, N. H., recently desired to ', City put up a new repair shop, there stood in k can the way 2 house, one half of which occu- nity of pied part of the proposed building-site. The other half of the residence stood on rt of an adjoining lot. nt for When certain conditions made it im- etween possible to move the entire house, the ¢ contractors decided to cut the dwelling in | feet 3 half and remove the half that occupied weight the building-site. After making a straight ve cut from roof to basement, they walled up driving the exposed side, as shown in the illus- eros tration. t plant View of house after the operation POPULAR SCIENCE MONTHLY The collapsible dining-room when it is unfolded (above) and folded (at the right) Folding Dining-Room Economizes Space N UNUSUAL collapsible dining- room that folds up to the size of a bookcase and that can be moved from place to place on casters, re- cently was patented by an architect of Washington, D. C. When folded, it resembles in ap- pearance an old-fashioned folding bedstead. When it is to be opened for a meal, the central panel swings downward to rest on a hinged support. Two side ; H panels also swing downward and unfold to Electric Sign a Block Long form two benches, each of which will seat Hair baal HE world’s largest electrical adver- two persons. se tising sign now flashes out the merits The opening of the panels exposes a r women lich may rists or of the shown it motorists nent. The small hostess ‘* ana at home” to her friends in the playhouse of a brand of ginger ale from a building dozen shelves for dishes and the table in Times Square, New York City. The linen; also two drawers for silver. The sign extends for an entire city block and table may be used for an ironing-board if is 58 feet tall, almost equal to the height desired. It is claimed that this novel of a six-story building. dining-room can be handled by a child. Complete Playhouse Has Electric Lights NE of the !at- est attractions at Vancouver, B. C., is a child’s playhouse that is a perfect model of a real ‘“‘grown-up”’ house, including real electric lights, furniture, kitchen and dining-room equipment, porch, lawn, shrubbery, and all the rest. The miniature home was built by Capt. W. Simpson for his small daughter. The young housewife is shown Officiating at a formal ‘‘at home’ for her little friends. ©vu.&U Ornamental Lamp of Cord Made by a Sailor HE first lamp made entirely of cord recently was exhibited in a New York hotel. This unique lighting fixture took a year of labor by a Spanish sailor, Juan Rios Rivera. It was said to have been made for a beautiful girl Rivera fell in love with after he had rescued her from death by drowning.

Page 64

POPULAR SCIENCE MONTHLY The steel generator shaft, 27 inches in di- ameter, after the cuts had been completed Torch Cuts through Huge Shaft in 10 Minutes HUGE generator shaft of solid steel weighing 40,000 pounds and measur- ing 27 inches in diameter recently was cut through five times by a torch in the re- markable speed of from 10 to 17 minutes for each cutting. Owing to the intense heat encountered in such heavy cutting and the consequent punishment to the operator in attempting to manipulate a torch continuously for the length of time required to complete a cut, an ingenious device was rigged to carry the torch at the required uniform speed up and over the shaft as the cutting progressed. The device consisted of a pipe frame- work erected over the horizontal shaft and supporting two i14-inch parallel steel rails laid six inches apart horizontally across the shaft and three feet above it. Making a cut. Notice the ingenious carriage on which the oxyhydrogen torch is guided The oxyhydrogen torch was fastened to a carriage traveling on these rails and propelled by hydraulic pressure from the oxygen line. Vertical motion was ob- tained by another device clamped to the torch and carriage, the speed of which was controlled by a water piston, as shown in the inset above. Eight cylinders of oxygen were con- nected with a manifold on the high pres- sure side and the oxygen was delivered to the torch through four manifold regula- tors. The gas consumption was 600 cubic feet of hydrogen and 2000 cubic feet of oxygen an hour. The shaft was cut for use as material for making drop forgings. Machine Cleans Six Tennj Balls at Once A MACHINE for cleaning soiled te,, nis balls consists of an_ai.tigh cylindrical box in two sections. The balls are placed in position in the holder, , soap solution is applied to each ball, the cover is attached, and while a hand rotates the balls, water is run through, connections at the base, forming a lathe After washing, the machine is draineg the cover removed, and the balls ay allowed to dry. application. issue What are vitamines? vem SSANS VW 12. How Much Science Do You Know? o- you ever stop to think how much success in your business or profession depends on a working knowledge of simple scientific facts? In the shop, the factory, or the office, have you observed that the man who always is ready with the correct answer when a question is put to him is the man who is in line for advancement? The practical knowledge that leads to larger pay envelopes and greater independence is the knowledge of scientific facts in their useful How much science do you know? Below are a dozen questions chosen at random from hundreds of queries from PopuLtar Scr—ENcE MontTHuLy readers. the best of, your ability, then turn tothe correct answers on page 132 and see how nearly you are right. But don’t.read the answers until you have studied each question thoroughly. Another test of 12 questions and answers will appear in next month’s Why is it hard to run uphill and easy to run down? How did stars come to be put into constellations? Why is there no air inside an electric-light globe? Can energy be destroyed? Give reasons for your answer. Why does a giraffe have such a long neck? What is an echo, and how is it caused? How much does the earth weigh in tons? What is an electric current? Can we see atoms of matter with a microscope? 11. What is the most valuable of all known metals? What is it that makes a person feel hungry? Answer them to Tennis-ball cleaner open and closed Belgian Mine Shafts Sunk in Columns of Ice N ORDER to mine rich coal beds inf Belgium that were practically ina cessible by marsh land lying over them, engineers devised a means of sinking the shafts in columns of ice. Two suti shafts already have been sunk appror imately 2500 feet at a cost of more that $1000 a foot. The system consists of freezing portions of marshland in the form of cylindric columns of ice in which the shafts a sunk. To do this several holes about! yard apart are drilled in a large «rc around the proposed shaft. A_verticd pipe sealed at one end then is sunk in eat! of these holes and a freezing solution ¢ salt run through them, forming aroutt each pipe a zone of frozen bog thi spreads until it joins zones of adjoinilg pipes. The refrigerating machines used are based on the evaporation of liquefia'# gases, such as ammonia and carbo dioxide. These are compressed 2! liquefied in coils of a condenser that kept cool by passing water over the continuously. The liquefied gases thei pass through refrigerating coils 0 which the freezing liquids circulate. 4 the gases evaporate they create inte” cold, freezing the water around them. Seven months were required to fre the first shaft and 21 months to sink® shaft at a rate of little more than th* feet a day. move acros: degre numk each In | with tical top of Che An a preser Scienc comm societ ny The \ Ica Bertrs view E.P. a Houdi gation engros Aut direct, Educa Practi, autom B John }

Page 65

nnis led ten. ai. tight he balls older, 3 all, the handle througi 2 lather drained, alls are closed » Sunk Ce al beds it ally inat- ver then, inking the Two sui k approx more that 1g portions eylindried shafts att es about: arge circ A. vertica ank in eat! solution ¢ ing aroun bog that f adjoinitg ; used a liquefiatl nd_ carbo! ressed all ser that a over the? gases thé coils ov® ‘culate. - rate inter 1d them. od to frees to sink & . than the - Improved New Level Made in Three Sections AN IMPROVED 48-inch level of al uminum is made in three 16-inch sections that dovetail together and are securely fastened by thumb-screws. When taken apart, the sections fit into com- partments in a leather case. The entire outfit weighs only four pounds. A valuable feature of the invention is ‘the level indicator. Variations are shown in degrees on a disk. As the level is Above: The three sec- tions of the new level, showing indicating disk, spirit level and plumb, and calculating table. Right: The handy carrying case moved up or down, a weighted indicator across the face of the disk points out the degrees of variation. A table gives the number of inches rise to the lineal foot for each degree. In addition, the instrument is equipped with a horizontal spirit level and a ver- tical spirit plumb. A V groove along the top of the level is used for sighting. Recent Publications Chemistry in the Twentieth Century. An account of the achievement and the present state of knowledge in chemical science, prepared under the guidance of a committee representing the scientific societies of England, and edited by Dr. F. Armstrong, F.R.S. Illustrated. The Macmillan Company. Icarus, or The Future of Science, by Bertrand Russell, F.R.S. A pessimistic Mew of coming scientific achievement. E. P. Dutton & Co. A Magician among the Spirits, by Houdini. The story of a 30-year investi- gation of spiritualism told in a thoroughly engrossing way. Harper & Bros. Automotive Repair, by J. C. Wright, director, Federal Board for Vocational Education. Four volumes of thorough, Practical instructions in every phase of automobile repair work. Illustrated. John Wiley & Sons. POPULAR SCIENCE MONTHLY , OM -. agate NG: BRR A] th Vapi fase Workmen Hoist Selves on Aerial Scaffold O REPLACE the cumbersome and sometimes hazardous scaffolding, tackle blocks, and rigging ropes used in construction work, a French manufacturing concern has perfected a device known as a “skyscraper’’—a small platform on which a workman can hoist himself to any height required by his particular job. The platform runs up and down a vertical wire cable and operates on the windlass os principle. By turn- ———— ing the crank of a winch the operator can raise or lower himself at will. A braking mechan- ism holds the car stationary on the cable at any desired point, leaving the operator’s hands free. The cable, suspended from a high point on the structure where it is to be used, will support three tons. A worker with his helper and their tools can be carried. Constructed entirely of metal, the in- vention is said to combine the maximum of safety with the minimum of effort. The illustration shows the invention being tested beneath the Eiffel Tower. Chinese Trees for Pulp EEDS of Chinese fir-trees, which are particularly suited for the manufac- ture of wood pulp, are being tried out in the United States by the Forest Service in the hope of adding to the nation’s pulp resources. 2 vapec q Running the OST automobile owners know that a new car should be run carefully and cautiously at least for the first 500 miles. But did you know that an overhauled engine should be run with equal care after it comes from the shop? This is because an engine, after an overhauling that includes the fitting of old and new parts together, is in much the same condition, so far as friction is concerned, as when the new parts were assembled originally at the factory. It is “‘stiff,’’ and demands care in running if it is not to be dam- aged. A safe procedure for running the engine under such conditions is as fol- lows: Before starting the engine, fill the crankease with half again as much oil as usual. Be sure that the radiator is filled with water and that the fan belt is adjusted correctly. ‘Stiff’? Engine To every gallon of gasoline add one pint of oil for the first 500 miles. After starting the engine, inspect the oil pump to see that it is working properly. To make sure that the upper parts of the cylinders, piston rings and pins are lubricated, shoot a small amount of oil from an oil gun into the air intake of the carburetor. Repeat this at inter- vals for half an hour, or until the lubri- cating system is found to be working properly. If the water in the radiator shows a tendency to boil, run a hose to the radiator, and through this feed in cold water as fast as the hot water can be drained through the petcock at the bottom of the radiator. Let the engine run idle for several hours. For at least 500 miles do not drive the car faster than 20 or 25 miles an hour.

Page 66

66 W hat’s By Jack Binns America’s foremost writer on radio YILL the perfect loudspeaker be produced this year? Ever since the advent of broadcasting it has been realized that the “speaker” con- trols the future of the science. In the United States, England, and France every available effort is being concen- trated upon the this instrument. Dr. C. W. Hewlett, an American scientist, has produced a new speaker that has no iron in it at all. Neither does it re- quire a horn. It is based on the induction principle. Instead of the usual horn, it has an aluminum diaphragm mounted in a frame and sur- rounded by flat coils of wire close toit. The coils carry direct cur- rent that produces a radial field over the diaphragm, which in the largest model is thirty-six inches in diameter. The same coils carry the amplified voice currents, and the interaction be- tween the currents causes the diaphragm to vibrate. development of HE present model, however, is suitable only for very loud work. An entirely different method is being employed in a speaker developed in England. This is based on the electrostatic prin- ciple, developed by two Danish engineers, Johnsen and Rahbek. It involves the phenomenon ex- isting when a semi-conducting body, such as , 1s brought metallie sur- face, and a difference of potential maintained at th tact. This hnetween the two objects. Y¢ atine In contact wi point of con- causes an adhesion Any change in voltage will cause a

POPULAR SCIENCE MONTHLY

fT ns Pm clock hands in re- 5 -. — — \ sponse to radio time - signals is a recent \ achievement of the in the new speaker, advantage is taken of this effect in the following manner: A metal cylinder is slowly rotated in close contact with a band of gelatine covered on the outside with tinfoil. One end of the gelatine is connected with a spring, the other with the diaphragm of a loud- speaker similar in construction to the sound box of a phonograph. In operation, a steady voltage is main- tained across the tinfoil. This produces a United States Bureau of Standards. system of radio re- lays the signals actu- ate the hand-set- ting mechanism

For the first time in history speeches and entertainment have been broadcast from a steamer at sea.

Above is a view of station Automatic setting of By a New in Radio Invention steady adhesion between it and the gela- tine, which maintains a steady pull on the diaphragm. The pulsating current from the radio amplifier causes changes in the adhesion, and these in turn actuate the diaphragm, causing it to give off sound. In France most experimental work with speakers is being, concentrated on large diaphragms that eliminate the neces- sity of horns. It is recognized that the latter merely concentrate the sound waves. They do not in any way amplify their volume; in fact, they absorb some of the energy. The Hunt for Static CIENTISTS ha:e come at last to the realization that the best way to eliminate the evil effects of static is first to learn its habits, where it comes from, and the hours it keeps. With an intelligent knowledge of these facts more progress call be made toward its elimination than by any of the haphazard methods at present employed. Somewhere off the New Eng- land coast engineers of the American Telephone and Tele graph Company’s laboratories have installed an automatic re cording device that makes a per- manent record of the strength, duration, and direction of all static discharges within range 0 the sensitive apparatus. In the short time it has been in operation two very important facts have been learned regard: ing the enemy of radio. First, It has been found that there 18 4 marked decrease in the value 0 static every mornrirg at sunrise, irrespective of weather co! tions. Second, the observations eondi-

} ; +> a the have indicated that most of th static received on the easté orig: coast of the United States orresponding change in the de- WSN aboard the liner Leviathan, from which the program was inates in the south west. Th ea 3} : sent. A radio engineer is seen testing the wave length of the F ae *. that if 3 gree of aanesion station with a crystal set, preperatory to broadcasting conclusion drawn 3s ed reflecting follows th gill reflec hesouth the inten The a] loop ante joop is I indicates static 1S automati in this 17 quency < isfed int mocoupl vanomet includes sity of t] Safe N 0 nen rated. part in t in this s fields ar system effective of signa! Proba able of however! ed “field sists of above t what i invertec

The mas lanc to t wei cone j; Up in caugh: landin Ing dc curate The the la: “wave

Page 67

Nn > gela- on the t from in the te the ind. work ed on neces- at the sound y way 1 fact, nergy. atic me at 1 that ce the rst to comes keeps. vledge ss can nation azard yed. , Eng- f the Tele- tories tic re- @ per- ongth, of all nge of ; been ortant ogard- irst, it e is 4 Jue of inrise, condi- ations of the aster! : orig: The et a reflecting wall separates day and night, it ollows that as this wall passes a station it sill reflect or refract the static waves from :hesouthwest and act as a shield to reduce she intensity of the static at sunrise. “The apparatus employed consists of a loop antenna that picks up the static. A loop is highly directional, and therefore indicates the direction from which the static is coming. The loop is rotated jutomatically, and the energy picked up in this manner is passed into a radio-fre- quency amplifier. The output from this isfed into the heating elements of a ther- mocouple that operates a recording gal- yanometer. In addition, the apparatus includes a means for measuring the inten- sity of the static noise. Safety for Air Mailmen N JULY first the new transconti- nental air mail service was inaugu- rated. Radio is playing a remarkable part in the safety of the aircraft employed inthis service. All the landing POPULAR SCIENCE MONTHLY Four different sized models of the latest in radio loudspeakers—the felds are linked with a radio system that approximates in eflectiveness the block system of signaling on railroads. Probably the most remark- able of the safety measures, however, is the newly develop- ed “field localizer.’”” This con- sists of an electric wave spread above the landing field some- what in the shape of an inverted cone. The apex of the The base of one of the 16 largest wireless masts in the world, erected at Rugby, Eng- land. They will make it possible for London to telephone New York. Each great mast Weighs 140 tons and is 820 feet tall cone is on the landing field, and the base Up in the air. With its aid, an airplane ‘aught in a fog can be guided safely to a anding, because the ‘“‘wave field,” narrow- ing down to a cone, becomes more ac- Curate as the machine nears the ground. ” The pilot knows he is in the vicinity of the landing field as soon as he picks up the Wave field” with his instruments. Then by carefully man- euvering his ma- chine downward, he can reach an altitude where he will be able to see the landing field through the haze. Direction find- ers also are to be installed on the transcontinental air - mail _ ships. These will enable a pilot to steer a straight course be- tween scheduled stops should he be overtaken by unexpected foggy weather. There is no doubt that aerial navigation and radio are bound together inseparably. In fact, without radio, organized flying on sched- uled time-tables would be impossible. View of the giant mast, looking upward Facts about Broadcasting ome interesting figures have just been compiled regarding broadcasting sta- . tions. These show that 79.3 per cent of the stations licensed in this country are ope- rating on lessthan 500 watts, an amount of power generally considered inadequate. There are 93 stations with 500 watts out- put, and 14 using more than that amount. Another interesting analysis shows that 53.8 per cent are operated by radio and electric companies, dry-goods stores, newspapers, and other private corpora- tions. Of the remainder, 17 per cent are worked by governmental agencies, federal, state and municipal, and 3.5 per cent by churches. There is a strong tendency to bring about the elimination of the 79.3 per cent using less than 500 watts and to concen- trate on the better type of broadcast sta- tions strategically located with regard to centers of population hornless induction loudspeaker developed by Dr. C. W. Hewlett, physi- cist of the General Electric Company, who is shown above in his labora- tory. The largest of the models, 36 inches in diameter, has been installed near an auto-tourists’ camping-ground at Schenectady, N. Y., and can be heard 500 feet away, insuring entertainment for a large audience Marconi’s Remarkable Work | Sarna eicmeaguenee ye progress apparently is being made by Marconi and his assistants with the ‘‘directed beam” sys- tem of radio communication on wave lengths of one to 15 meters. The latest reports indicate that successful telephone communication between England and Argentina has been achieved. On this occasion the Argentinian Minister of Agriculture, Dr. Thomas Le Breton, who happened to be in England, spoke with War Minister Justo in Buenos Aires. As soon as Marconi’s work has been brought to a successful conclusion, it will be possible to put hundreds of trans- atlantic radio-telephone channels into operation without interference, and witha fair measure of secrecy. Radio and the Railroads a probably never will supplant the existing systems of railroad sig- naling and control entirely. It will, how- ever, make possible direct communication at all times with moving trains. This is of far-reaching importance. Its value when storms disrupt the telegraph lines cannot be overestimated. The Pennsylvania Railroad has just completed experiments with special sta- tions erected at Camden, N. J., Pitts- burgh, Chicago, and St. Louis. The re- sults obtained with moving trains were very successful. The company now is considering the advisability of establish- ing radio stations as auxiliaries to its telegraph and telephone lines. One of the possibilities of this system is that engineers of trains can keep in direct touch with the dispatcher’s office at all times during the trip. This will make possible a strict control of each train, thus minimizing the danger of accidents. This is an immediate possibility. Another pos- sibility of the near future involves tele- phonic communication between business offices in cities and passengers aboard express trains.

Page 68

68 POPULAR SCIENCE MONTHLY Back-Stage with “Radio Mike” How Broadcasters Send Realistic Drama over the Aur By W. T. Meenam F YOU ever have listened to drama over the radio, have you wondered how effects of rain, thunder, wind, and similar noises are created before the micro- phone in the studio of the broadcasting station, to add vivid reality to the spoken play? Successful transmission of a dramatic production by radio is greatly dependent upon sound properties to take the place The torch produced the effect of rushing wind and flame. The paper, crushed close to the microphone, sounded to radio audiences like the crackling of burning tree branches. The breaking of small matches produced the realistic effect of the breaking of huge tree trunks. In the production of another play, en- titled “‘The Fortune Hunter,” a rain- storm was necessary. Instead of waiting to broadcast on a stormy night when the real rain might be available, a thoroughly Onondaga Indian braves, in full regalia, enacting an Indian war dance before the microphone in the broadcasting studio of Station WGY, Schenectady, N. Y. This probably was the first time that a war dance had been broadcast by wireless of stage action. Thus atmosphere is created and the imagination of the hearer is stimulated. To obtain this ‘atmosphere many devices are impro- vised to suit the needs of a particular production. Considerable experiment- ing often is necessary to produce the sound desired. It is easy to imagine how such com- mon noises as the slamming of a door, the breaking of glass, the barking of a dog, or the ringing of bells are repro- duced for radio audiences. In fact, such sounds have offered few obstacles t» broadcasting producers. But when the manuscript of a radio play calls for such a spectacle as a forest fire, with crashing and roaring flames, what then? If the play is to be broad- cast successfully, a vivid portrayal of raging conflagration becomes vital. Just such a problem confronted the producers of a drama called “The Storm,” which was broadcast with strik- ing effect by Station WGY, Schenectady, N. Y. At the climax of the play a great forest fire was to cut off the hero, heroine, and rival from the rest of the world. The way in which the effect of this dramatic setting was sent “‘over the air’’ was re- markably ingenious, especially since it was produced before the microphone with such simple instruments as a blowtorch, matches, and paper. trees gasoline Edward H. Smith, director of the WGY players, with the bell board and door used to produce sound atmosphere for the radio drama. The bell board contains door, tele- phone, clock chime, alarm, tap bells and buzzer, all connected with dry batteries and operated by the pressure of a button. The entrance and exit of characters are indicated by the sound of the opening and closing door realistic effect was created sitaply by rell- ing dried peas through a paper tube directly in front of the microphone. The paper tube magnified the sound so that to distant radio listeners the effect was a first class rainstorm. The staging of a fight scene before the microphone in such a way that the thrills will not be lost to the invisible audience is surprisingly ingenious. In such a scene from ‘‘Pierre of the Plains,’? which was broadcast not long ago, “Jap”? Durking, ? the villain, fires at Pierre from ambush. Pierre feigns death and falls in the degg leaves carpeting the forest. Then, as Dy. kin approaches, Pierre grapples with his enemy and kills him in a desperate hang. to-hand conflict. Pierre rides away on his horse. In “staging’’ this scene, the shot fired by the villain, of course, is produced bya revolver. In the hand-to-hand fight the actors grapple knee-deep in onion-skip paper, and a microphone on the floor picks up the sound of the rustling paper Broadcasting the fight scene in ‘Pierre of the Plains.”” A revolver fires the shot in- tended for Pierre. Then the actors por- traying Pierre and his enemy grapple knee-deep in onion-skin paper, rustling the “leaves” in their realistic struggle leaves as they are scattered in the struggles of the men. At the end of the battle, the sound of the horse’s hoofs as Pierre rides away is produced by drumming with sticks on a wood sur- face. In order to have within easy reac frequently used bells, the ‘property man” of the WGY ‘“‘radio theater’ constructed a bell board containing al! the necessary combinations such 3% doorbell, telephone bell, call bell, and buzzer, mounted on one board and connected with batteries. Burglar. ambulance, and fire alarms, a clock chime and tap bell also were included. The entrance or exit of a characte! in a radio drama must be conveyed to the invisible audience by the audible closing of a door. This is one of the peculiar conventions of dramat broadcasting. Generally, in dramat! production, a softly closing door is desi able and conventional, but over the 2! the actual sound of the closing of the door is the only means of denoting the exit entrance of a character. Therefore a sm2! portable door of thin oak in a special mounted frame with peculiar reson was constructed so that the noise ol “ ing it could be transmitted easily 2”! that the turning of the key in th also would be noticeably audible to ' thousands of unseen “play-goers.’ Jos Popul most : selecti ing sé the di is to ¢ Bec ever, their | king « a feat In reque Mon’ ing, i just odyni Fo as ut three as a ceive necti simp] comb Static Th }—

Page 69

' [How to Build a Super-Heterodyne Part I—The First Detector and Two-Stage Amplifier Units € dead aS Dur. ‘ith his > hand. on his ot fired od bya tht the on-skin € floor » Paper rre of 10t in- $ por- rapple istling ruggle in the 1d of the ’s hoofs uced by ood sur sy reach property theater” ining all such as yell, and ard and Burglar, a clock neluded. haracter veyed to audible e of the (ramati iramati is desit- the all the door POPULAR SCIENCE MONTHLY 69 Fig. 1. By Joseph Calcaterra Radio Editor of Popular Science Monthly HE super-heterodyne T is recognized gener- ally as being the most sensitive and the most selective of all radio receiv- ing sets. For that reason the dream of almost every real radio fan isto own one sooner or later. Because of its size and intricacy, how- ever, many persons who like to build their own sets have hesitated to build this king of radio instruments. Yet such afeat is entirely possible. In fact, it is in response to many requests from POPULAR SCIENCE MONTHLY readers that I am describ- ing, in this and next month’s issues, just how to build the super-heter- odyne. For the sake of simplicity, as well as utility, the set is constructed in three units. It can be used not only as an eight-tube super-heterodyne re- ceiver, but, with slight changes in con- nections, can be adapted for use as a simple three-tube non-regenerative honey- comb-coil receiver for reception of local stations with an outside aerial. This month I shall describe the con- Two views of the oscillator and first detector units, showing layout of parts numbered and lettered to correspond with Fig. 5 struction of the oscillator and first detector unit, and the two-stage audio-fre- quency amplifier unit. Next month I shall tell how to build the intermedi- ate amplifier and second de- tector unit. In addition, I shall give complete instruc- tions for connecting the units, and tell how to operate the complete receiver. The symbols on the wiring diagrams of the detector and amplifier units, shown at the bottom of the page, have been numbered and lettered to correspond with the various parts on the photographs. Front view of panels of detector (left) and two-stage amplifier units, showing controls La yale 1 and 2 of the detector unit (Figs. 1 and 8) are the aerial and ground terminals respectively, when such are to be used. When a loop aerial is used, one end of the loop should be connected with terminal 1; the other end with terminal 2. Number 3 is the negative A-battery terminal, and No. 4 the positive A- battery terminal. Number 5 is the variable condenser used to tune the oscillator circuit to the desired frequency. This condenser should have a capacity of about .001 microfarad and should be provided with a Vernier (Continued on page 133) Fig. 2. Layout of two-stage audio- frequency amplifier unit, withsymbols cor- responding to Fig. 4 Pp 36 ¢G G 37 p frequency amplifier unit shown in Fig. 2. In each ase the symbols correspond to the numbered and in the photographs shown abov At the left is the complete wiring diagram for the oscillator and first detector unit shown in Fig. 1. The diagram above is for the two-stage audio- lettered parts

Page 70

70 Radio Hints for Everybody POPULAR SCIENCE MONTHLY LTHOUGH you cannot eliminate part of the house’s steam-heating system. static, you can, without much Now, the “ground” is almost as im- trouble, cut down the amount of portant an aid to good reception as the static that crackles in the head phones aerial, and for this reason you should spare or loudspeaker of The surest way to do so is to use an indoor’ aerial — either a loop, or a single wire stretched in the attic, along a hall- way or around a picture molding. With an aerial of this sort you can pick up local pro- grams just as satis- factorily as with an outdoor aerial, and with virtually no static interference. You can get dis- tance, too. If inconvenient to use an indoor aerial, you can min- imize the amount of static your set picks up by lower- ing your outdoor aerial, setting it up, say, within from 12 to 20 feet of the ground. And your receiving set. neither pains nor trouble in supplying it. for various stations, for example, probably will not bring in those stations. The ger. sitiveness and selectivity of your receive, also may appear to be impaired. Ther is no way to remedy these condition; except through ex. A Boston radio enthusiast has perfected a six- out antenna or ground wires. He says he has tube super-heterodyne set so sensitive that he heard 25 stations from his car in one loca- periment. Rechart your dial settings. Raise or lower, lengthe or shorten you aerial. Be certain that you have , good ground con. nection. Don't, however, attempt any drastic altera. tion of the set it. self, for you may thereby store w trouble for yourself after your retum home. OMETIMES the source of radio troubles is elusive because itis in such an obvious place, you never ial think of looking for © Keystone it there. A scratch: ing noise, for ex uses it in his automobile, as shown above, with- tion, and is always assured of entertainment ample, easily may welt If possible, it should be a special iron pipe, or plate, buried in the ground a few feet from the wall of the house, and it should be as close to your receiver as you can get it. In other words, the lower floor of a house is the best location for a radio set, and the ground connection should be made direct, not through a complexity of water pipes. F YOU have a portable set, or if you remove your stationary set to camp or hotel during your vacation, remember that various conditions affecting radio reception may be decidedly different in the new location. Hence, you must not expect your receiver to function the same as when you are at home. The dial settings that you have charted This compact battery charger, plugged into an electric-light socket, is designed to recharge a radio storage battery overnight. An aluminum cover protects the apparatus, which is said to de- liver as much current as 7'3 am- peres, consuming only 75 watts even if you cannot, for some of these things, you can keep static down by tuning in the local reason, try any stations only. N OST people, when they buy radio sets, put up the best aerials they can. Few, though, bother much about their ground connec- tion. The nearest and hand- iest path to the ground usu- ally suffices, whether it be a water pipe, a gas pipe, or The newest thing in vario- couplers is this ingenious com- bination using a_ spider-web primary, spider-web secondary, and a separate three-turn coup- ling coil. All windings are so arranged that the electrostatic coupling is practically ‘‘zero” be caused by loose phone connections. More than one fan, after spending hours inspecting t ceiver, aerial, and ground in a search for the possible causes of the scratch, has dis covered the trouble in a loose connection in his phones. When the receivé! “scratches,” look first to the phones. Connect the phones, You can talk through your loudspeaker simply by connecting the head otr ble e trouble set across the primary of the transformer of the first stage amplifier, and the phone cord. If yo know speaking into one of the phones, the B battery being connected as usual is there, you soon Wi 10¥. turn on the tubes, and shake Doct peare to hi ike we fields easy f person than @ labora usual]: portio that li The Weatt in col Army has u that makin its rep of flig halloo at the than-s Field, Wh reau make eries” flights gathe free-g other Wh travel We st blowi path partic Un by le given horizi

Page 71

obably he ser. ecelver There ditions ugh eX.

POPULAR SCIENCE MONTHLY

71 Riding the Storm to Make the Air Roads Safe By C. LeRoy Meisinger Meteorologist, United States Weather Bureau balloon. In clear weather, this means

The vertical diminution or increase of

‘ Bare only close attention to maps as the balloon _dustiness is of considerable im portance as ongther proceeds. But when the earth’s surface a basis for studies in visibility, which is so sane is obscured by clouds, there are two means important in aerial navigation. oman of checking the path: One is to drop Equally important to visibility is sky haw 4 weighted postcards that may be found brightness. Equipment is carried also a oe and returned by the finder with a notation for the measurement of th is. Don't TS. Air as to the time and place of finding. The A radio receiving set'is carried in the attempt 7 Service balloon, and the forecaster dine cosa pag. olay agit A at W ashington is able to set it. ” his death in the storm communicate to the per- Qu may A Martyr in the Cause of Science Gas ee oe wo = — > EHIND the recent brief newspaper accounts of the tragic changes in weather condi- : si faboratory 18 the a death of Dr. C. LeRoy Meisinger, expert meteorologist tions in the region in which mosphere itself. Un- of the United States Weather Bureau, lies as dramatic a tale of they are flying. These bulle- ike workers in many other bravery as ever came from a field of battle—another heroic tins have been very valuable fields of science, it is not chapter in the ceaseless adventure of science into the strong- i as Te ‘ IMES easy for the meteorologist holds of the unknown. Doctor Meisinger and his pilot, Lieut. HE first fig] urce of versonally to work in more James T. Neely, died in action near Bement, Ill., when E first flight of the ibles js caval weantion of tin lightning destroyed the free balloon in which they had deliber- series was made by the 7 + an as port: ately set out to ride the storm. author with Lieut. L. A. use Its HM laboratory. His efforts D bar . ee . ‘ lvetoes ’ 2 octor Meisinger proposed to make the air safer for aviation Lawson on April 1 and 2, Obvious HM usually are confined to that b sisttses shan tea tite of f h a PE aE hte Nagios I} : by studying the habits of storms so as to forecast them unfail- 1924, and subsequent flights ad portion of the atmosphere ingly. It was his idea that this could be done best by taking have been made with Lieut king for HF that lies next to the ground. part in a storm, allowing himself to be buffeted about in its Tome "T'. Mache. tatieue scratch- The United States relentless fury while he charted its movements and air currents. called ‘ilot ape: f the Aj ; for ex Ti Weather Bureau, however, The fatal flight was the ninth of a series of hazardous expe- phone staphic irregularities also play an impor- ‘ant part in introducing vertical motions in, after into the air; but at higher levels this is cting re ‘ot So conspicuous. ‘ound in _ Therefore, if we may send a manned possible J ‘ee balloon to some stated level, cause it has dis “Maintain its elevation as constantly as n a loose Possible, and have the observer note care- ones. ‘Uy at all times the course of the balloon, ceive! “Me resulting path will be a close approx- st to the “nation to the movement of air at that . phones, evel, This is precisely what is being 1d shake attempted at Scott Field. o trouble he work is dependent for its success il] know. “pon the knowledge of the track of the

other is to determine the balloon’s posi- tion by astronomical observation accord- ing to standard methods of navigation. This latter method is used only when the sky is clear overhead. HE balloons being used are of the spherical type employed for military training and balloon racing. The capacity is 35,000 cubic feet and hydrogen is used as the buoyant gas. The total lift is about a ton, approxi- mately half of which is carried as expend- able ballast. Under favorable weather conditions, such a balloon might be able to remain in the air from 36 to 40 hours, but usually this is not possible; and, when rain falls on it long, the added weight necessitates so rapid an expenditure of ballast that the flight cften is terminated within from eight to 10 hours, sometimes even less. Besides the fundamental work outlined above, data are being gathered in connec- tion with other investigations. For in- stance, dust samples obtained at various elevations enable one to know the number of dust particles in a given volume of air.

the thrill of adventure. Courtesy U.S. Air Service

Doctor Meisinger’s balloon taking off from Scott Field for its ninth and last voyage

Page 72

72 POPULAR SCIENCE MONTHLY New Scientific Aids to Industry To promote the production of scientific machinery for industry, the British National Physical Laboratory at Teddington, Middlesex, is conducting experiments on a large scale in every branch of physical science. These pictures show some of the most interesting tests

Above: Measuring daylight illu- At the right: Testing heat-measur- mination from four quarters of the ing instruments by comparing them sky by means of a special triangular in heat radiated through an obser- screen and brightness recorder vation hole in a special furnace

This gear-measuring machine checks the accuracy of high precision cut or ground gears. Tooth shapes are reproduced on smoked glass by means of a pantograph

To obtain the best possible daylight il- lumination for an extension of the famous Tate Art Gallery in London, experimenters are shown above mea- suring the daylight factor in a small scale model of the structure. The measurements are made with a special daylight meter called a “hermera- » photometer,’’ and " i . = | ; are recorded by the Si . 5

Checking Swedish-type gage blocks with a machine that detects inaccuracies UP to one-millionth of an inch. The blocks are shown in the tray in the foreground

Page 73

for ’ at na 1ese ests with ss up locks ound POPULAR SCIENCE MONTHLY 73 Where Is the Automobile Going? An Expert’s Forecast of Improvements in the Next 25 Years By Leslie V. Spencer, M.E. Looking a little further into the future, undoubtedly we shall laugh whenever we HERE is the automobile going? inspect cars with any sort of intermediate W What sort of motor vehicles will system of gears at all. The gasoline engine the drivers of the future operate? of the years to come will run so smoothly At the rate of There will be no shifting of gears back and forth, for there will be no gears to shift. The drive will be direct from the engine to the rear axle, just as a great many racing cars are built even now. Already we have development main- tained during the last 25 years, the motorist of 1950 will laugh heartily at our finest gasoline crea- tions of today, just as we cast an amused eye upon the horse- less carriages of 1900, with their funny dashboards, their chuggy engines underneath, and their short wheel base. For undoubt- edly the forces that have developed the motor-car to its present degree of perfection will con- tinue their influence. The quality and price of fuel, for ex- ample, will play an important part, for gasoline transporta- tion units always must take the fuel hints of changes in gearsets. One prom- inent make of motor car is out with a gearset that effects changes of speed be- tween driving and driven shafts with- out meshing or de- meshing any of the gears. This means less shifting trouble, since one of the chief difficulties in shifting gears with- out grinding is that teeth of one gear actually must slide into engagement with those of an- other. | he THE new gear mechanism _re- ferred to, an ingeni- a: ous shifting of keys *. %.| is effected, the shaft | thus picking up the lbs ana. ee | desired gear, which problem into con- America’s oldest automobile as it appeared with the powerful, smooth-running car of is never out of en- sideration. Then, in 1893, driven by Elwood Haynes, its builder. 1924, shown below, illustrates strikingly the gagement with its the demand for Comparison of this little chugging machine amazing development of power along with : small bulk and low price must be reckoned and have such a nearly continuous flow with. Comfort, dependability, utility— of power that such a thing as drive these also are controlling factors. through gears will be unnecessary. Each year sees a greater tendency Steam cars today do not need gearsets toward making cars easier to drive and because the steam engine develops a simpler to handle. Beginning with the steady power flow at any speed, whereas self-starter some years ago, development the power of a gasoline engine is inter- along lines of simpler operation has been mittent. As gasoline engines have marked, until today cars are very easy to developed, however, they have ap- handle, even by the frailest woman proached nearer and nearer to the con- driver. Steering gears have been refined stant torque of the steam engine, and it is in every particular, gearsets have been logical to expect this development to studied closely with the idea of bringing continue. the shifting down to the least arduous This will mean an entirely new satisfac- degree possible. Pedal actions and accel- tion in driving. It will mean that you erator mechanisms have been arranged so will simply start your engine, move a that brute strength is not essential to connecting lever while the clutch pedal is efficient handling. All these factors have depressed, let in the clutch and proceed, tended to bring motor-car operation governing the car’s speed simply Within reach of an ever-increasing num- by the accelerator and the judi- ber of persons. cious manipulation of the clutch pedal. yet there is still much to be done along these lines; for, after all, with most cars, it is still necessary to shift gears around. to change.from-one speed to an- other, Undoubtedly the day is not far off when there will be none of the manual gear lever manipulation almost universal f in gasoline cars today. Some form of a the automobile mating gear. The motions of gearshift- ing are gone through with just as with any other gearset, but the resulting movement of the parts is not the same. This interest- ing development is, without doubt, the forerunner of a new order of things in the transfer of the power from engine to rear wheels. The entry of non-transmission vehicles into the field may be along with multi- cylinder engines such as we have not yet seen. One way of bringing about greater motor flexibility is to increase the number of cylinders. Although so far we have not gone beyond 12 cylinders in commercial cars, it is not at all improbable that the gasoline engine of 1950 may have 24 or 48 little cylinders so arranged that the power impulses come with a frequency that will automatic or semi-automatic change of Speed relation is in the offing. It will not © a tacked-on mechanism to go through - the motions required at present, but it will bean integral part of whatever type of gearing is used. The touring-car of today, with its tremendous power, its graceful lines, and ease of operation, may seem as crude and curious an oddity to the motorist of 1950 as the horseless carriage of 25 years ago, with its chuggy engine and odd-looking dashboards, appears to us

Page 74

74 be the next thing to continuous flow. In that future day when there are no gearsets at all, cars naturally will be much lighter and simpler. Simplification means increased efficiency and dependability. The simpler the mechanism, the cheaper it is to manufacture, and the less the pub- lic has to pay for it. At‘0: when you reduce the number of parts, with consequent reduction in weight, you make a car cheaper to run. Less weight means less power required to operate the machine, and hence less fuel cost. Is it, therefore, too much to say that we are almost on the threshold of the era of cheaper car operation as well as cheaper cars? Even if nothing is done save to cut out gear mechanisms, this era is assured. Another factor that has its influence on reduction of weight is the constant prog- VENTILATORS TO CLOSE OR OPEN UNBREAKABLE GLASS FOR ALL WINDOWS GEARSHIFTMADE UNNECESSARY BY 48-CYLINDER Bape LICENSE PLATE LIT UP AIR FILTER SELF- STABILIZING FRONT WHEEL ’ €E cee "EXTRA LARGE BALLOON TIRES ress in metallurgy. Metals used today in car construction are far in advance of what they were a few years ago. The Ford car, for example, would not be pos- sible at the price nor the weight if the present vanadium steel alloys were not used most extensively. Alloys with alumi- num, many of which have been perfected within the last few years, mean lightness with real strength, a most desirable com- bination. We are certainly nowhere near the ultimate in the development of combina- tion metals, for the metallurgical labora- tories of every big concern employing metals constantly are trying to come nearer to the ideal type of metal alloy for any given purpose. Perhaps in no indus- try is this activity more pronounced than in the field of car building. The cost of gasoline is going to force the development of engines which will effi- ciently use heavier oils that can be pur- chased for less money. Fuel oils that cost from five to seven cents a gallon are not adaptable now for motor-car use, but the days ahead will undoubtedly force the MOTOR. am POPULAR SCIENCE MONTHLY development of power plants that will run on such cheap fuels. One of two things soon must happen if internal-combustion engines are to keep other types from crowding them out as the means of motor-car propulsion. Either present-day gasoline must come down radically in price, which seems highly im- probable, or cheaper oils must be brought into use. As the number of cars increases, competition and public insistence will force engineers and inventors to develop ways and means for cheaper car operation. Think what it would mean to the auto- mobile public if every gallon of oil brought from the ground could be used in nearly its crude state in the operation of cars! a collecting device in proportion to the size of the vehicle. Then from this eo}. lecting arrangement the power will enter an electric motor to drive the car. We pect G still further into the future, one well can imagine the day of the combined airplane and road vehicle. Qb- viously, for short runs such a machine would be operated on its wheels, but once out of the city, or other congested area, it would stretch its wings and take to the air for long-distance hops. All one has to do to realize that such development is pog- sible is to think back a hundred years. Do you suppose the wiseheads of 1824 dared risk their necks by predicting any one of O WHEELS IN REAR ey DISAPPEARING STEP RUBBER OR AIR CUSHION AROUND CAR TO INSURE AGAINST DAMAGE BY COLLISION a JACKS ATTACHED TO FRAME » AND OPERATED FROM a DRIVER'S SEAT Our artist’s conception of the motor-car of 1950, based on Mr. Spencer’s interesting forecasts—A three-wheeled cross between the automobile and motorcycle, com- bining economy, comfort, atid ease of operation, with a light, smooth-running engine of many cylinders, requiring no gearshifts. Perhaps going all the way back to the oil- well is too big a step, but at least the type of oil now used by ships and for similar purposes ought to come eventually into motor-car use—a step forward that means almost unbelievable advance. ghd when the day comes that we have direct-drive cars propelled by heavy- oil engines, then we shall have gone as far as we can along the internal-combustion- engine path. With the rapid strides elec- tricity is taking, scientists and engineers predict a day when we shall have wireless power transmission for automobiles. The air will be filled with tremendous electrical energy from power stations, perhaps mu- nicipally operated. Each user of such power will have some sort of collector de- vice, and he will be licensed and charged so much a month, say, depending upon what amount of electric energy his intake meter indicates he has drawn from the ether. The big factory will have its giant. col- lector of power; each automobile will have, instead of an engine as we know it, Important improvements are indicated the mechanical marvels we think com. monplace today? But coming back to the near future, I think we can safely say that the open car, as we know it today, will be discarded. Every car built probably will have some form of convertible body, making it 4 simple matter to open it or close it, de pending upon the weather. Disappearing windows, doors, and side panels to convert the body already are on the way. The demand for cheap, quick trans portation probably is going to mean the building of vehicles that are a cross be tween the motorcycle and the auto mobile—perhaps little three-wheelers with light, smooth-running engines. Such cars will be most economical to buy and to run, and very easy to manipulate m traffic. They will be little one-seaters— or two-seaters at the most—perhaps with inclosed bodies to make them independ- ent of weather. They are a needed utility, and they are undoubtedly right ahead. Next month—How to eliminate caf bon and save trouble, fuel, and repatt bills in running your car.

Page 75

POPULAR SCIENCE MONTHLY 75 New Inventions for Your Car This new rear fen- der light (below), with concealed wire reel, throws a beam of light on the edge of the road, and (at left) can be de- tached if desired This gas cap for Ford tanks has a spring- hinged center. The hose nozzle is pushed through the cap, which closes automatic- Rear-seat passen- ally when the nozzle is withdrawn gers in open cars are given wind- shield protection by this collapsible device, which weighs only ‘\, afewounces gg OO OM This triple tail light cannot go out. When one bulb fails, another lights. Each is contrclled by an electromagnet that automatically trans- fers the current to the next as its bulb burns out. The bulbs light singly In this auto lock, ignition wires pass through a box with eight knobs, each controlling the wiring to one cylinder. Four, six or eight can be used 5 ME tee tproof auto lock combines nition lock, steering-wheel lock, SS and Steering-column bracket. It is This semaphore for closed cars enables the driver Situated on the steering-post of the , to signal without lowering a window. It is of automobile, where it enters the dash metal, painted red, mounted on the windshield

Page 76

course, in the thickest traffic. The new brush springs are made from cut-off safety-pins. Leads to the field coils of the horn motor are connected with the loops of the pins by short screws and nuts. The brush holders are slotted with a hacksaw to receive the new springs and the ends of the cut-off pins are bent over for about 1/16 in. of their length. Since the safety-pins have more spring than the usual small springs that come with such a horn, the brush pressure is much greater and a Ny good contact is as- Wi sured. SAFETY PIN 7 USED AS ARIOUS kinds ! of short-circuit Hi troubles are experi- f enced in automobiles because the insula- tion of the wiring has been worn through by chaf- ing against metal edges. Much of this wear can be overcome by running the wires through strong, homemade _ con- duits, as in Fig. 1. Safety-pin repairs horn motor Persie COMPO! yy * Ss —»> i = : at ey" Fig. 2. Procure an old a curtain - roller pin lla? spring and } stretch it to suit Fig. 3. Grease cups hold repair compounds the length of wires. Wrap the wires with friction-tape. Run them through the spring, then wrap the spring closely with friction-tape, making laps of not more than 14 in., being sure that each lap is well stuck to the one before. When the spring is fully wound, give the whole a coat of shellac. HE advantages of large grease cups 2s containers for valve grinding and soldering compounds will be apparent to the mechanic. Such containers may be stowed in the toolkit, without the usual annoyance of the materials’ escaping, as so often happens when they are kept in their original tins. Select grease cups of slightly different size, or one cup of brass and another of steel, for the different compounds, so that they can be distinguished readily. Bet- ter still, stencil the top to identify the contents. In the stem of each of the containers, tap a small thread for the insertion of a knurled thumbscrew, as is shown in Fig. 3. It is necessary only to screw down the cap of the container to release the compound —a quick, convenient, and economical method. Containers of this kind are especially useful to the auto-camper. Keeping Your Money-Saving Ideas TALLING of motor horns is one of the annoy- S ing troubles of autoists and it always occurs, of Frequently it is due to the fact that the brushes do not make very good contact—a difficulty that can be elimi- nated very easily by the method shown in Fig. 1. POPULAR SCIENCE MONTHLY Ber BRUSH SPRING S EVERY car-owner knows, the oil in the crankease of an automobile should be changed about every thousand miles or so if long engine life is to be ex- pected. However, it is not always easy to remember just when you did change the oil last unless you reinforce your memory with some sort of record. The simple counter shown in Fig. 4 SHELLAC TAPE Fie. 2. Fig. 4. Oiling record for garage made from checkers, leather washers, and odds and ends -EATHER STRA NS RUBBER ©. RIPS Ps Fig. 6. How leather straps and rubber pads are used to prevent engine hoods from rattling — serves the purpose admirably and costs nothing to make, as it is built out of five old wooden checkers, a few leather wash- ers, and a piece of heavy tin or sheet brass. The numbers on the checkers are cut from an old calendar and fastened on with glue. A long screw with a butterfly-nut serves both as an axle and as a clamping screw. Fasten the counter to the wall of your garage and when the oil in the crankcase is changed, set the recorder to correspond with the speedometer reading. Then you will know at any time just how far your car has gone since new oil was put in. Car in Good Order y=. for Auto Owners 7. valve-seat reamer shown in Fig. 5 is mag so that it can be used in different enging The feature is the stem or pilot, which is inte. changeable. About three stems are necessary with diameters 5/16 in., 34 in., and 7/16 in. respectively, The handle and stems are made of machine gteg| CURTAIN ROLLER Emergency conduit for automobile wires made from window-shade springs and tape and the cutter is tool steel, hardened, 4 tool like this is less expensive than thre or more reamers and will take care of the average job that comes into the auto. repair shop. © pw detail of the car that is difficult to silence, especially on trucks, is the hood. When one considers the ordinary method of hooking these down, it is ey dent that means of compensating for the wear are not pro vided. When the original fabric strips inserted in the ledges where the hood is seated have given way, they may be re placed with leather book straps, which are laced into the slits (Fig. 6) afte the buckles have been removed. ‘Where the hood seats on the car frame ledges, a side movement _ fre- quently will make a disagree- able rattle. A method to pre vent this also is shown in Fig. 6. Rubber pads made from short lengths of rub ber tube are car- ried around the ledges. FRICTION TAPE WIRES TAPED TOGETHER SPRING Fig. 5. interchangeable pilots Reamer with HEN relining four-wheel brakes, it is desirable to renew the linings of all the brakes at the same time, using the same grade of material, so that the identical thickness of lining will permit o more uniformity in the adjustment. The front wheels should be pointed directly ahead while adjustments are be ing made, for the reason that most of the brakes are constructed to release the out side wheel when turned either to right left. Adjust all the bands so that they ar uniformly tight, testing by slightly relea* ing the pressure on the pedal. It is contended by some designers that the rear brakes of the car should grip more solidly than the front in order to lesset interference with steering. However, construction that frees one front W when turning right or left normally meets all needs in steering with the brakes locked. Any adjustment to make th front brakes less effective than the re would be difficult for the average own or garageman to make and possibly ml , result in the front brakes’ not coming int? action. Shop versi' Popu

Page 77

yriginal nserted - where seated way, be re leather which 1to the )) after ; have d. e the ats on frame a side it fre y will isagree- les. oA to pre ; also is Fig. 6. r pads m. short of rub are cal- and. the rakes, it > linings e, using that the ermit of it. pointed s are be st of the the out right of they are ly releas- ners that rrip more to lessen evel, POPULAR SCIENCE MONTHLY Worksho Arthur Wakeling, Editor By Albert S. Peacock Shop Superintendent, New York Uni- versity; Consulting Expert on Tools, Popular Science Institute of Standards “ HY don’t you use a file, Jim?” W “File? What do you mean? Iam sharpening this plane iron.” “Oh! I thought you were try- Your Tools and Their Care been using it for seven years and have not had it refaced. Still, there’s not a single, solitary groove in it. Why? Because I move my tools in circles over the surface, covering the entire area. It isn’t so hard then to keep the bevel straight, and by moving in small circles I also avoid gouging the stone. ing to dig a groove into that stone you have there,”’ said Old Prentiss in a voice and with a smile that savored strongly of sarcasm. Old Prentiss had charge of the shop where I learned to know my friends, the tools. Jim was one of us—the gang—and had the makings of a good mechanic, but there were too many rough edges. -One of them was about to be knocked off by Old Pren- tiss, and I sidled closer to hear what he had to say. “Now, listen,’ the old fox continued. ‘‘Let’s see if we can apply common sense to this proposition, as we ought to apply it to everything we do. There are very few of us who can run our arms or our bodies back and forth in a perfectly straight line—I mean so that we can move a plane iron, a chisel, a knife, or any other tool straight back and forth across an oil- stone and keep the tool from rocking. I know you may have heard that that is the way, but let me tell you, 40 years at a game of this sort give a fellow a pretty fair notion of the best way to do a job; and the way you are doing it isn’t my notion of the right way. “Instead of getting a straight bevel on the tool, you are likely to rock it a bit and give it a convex surface. Of course, that doesn’t give the edge the proper shape. “Then, too, it stands to reason that you are going to dig a hollow into time stone. You’ve seen the one I have; I’ve oe Correct method of driving a socket chisel (at left), as compared with misuse of a paring chisel (at right) “Another thing—I notice that you seem to exert as much or even greater pressure on the backward stroke as on the forward stroke. What’s that going to do for you? It will turn off a heavy feather edge, and it’ll be some little job for you to remove the feather edge and put a razor edge on the tool. ‘‘Bear down on the forward stroke and you will cut against the edge, keeping the feather at a minimum and yet cutting sufficiently to give you a keen, sharp edge. Of course, you’ll turn off a slight feather, but that can be removed by giving it a stroke on the back, pushing the blade away from you and holding it per- fectly flat on the stone. Then give one stroke on the bevel, another on the back, and so on until the feather has worn off.” At this point Old Prentiss saw me over by one of the lathes with my head tilted at such an angle that he knew I was 39 “listening in.’? He took that as an invita- tion to launch into his pet subject—‘“‘the use and abuse of tools.” It was not a very busy morning, so he invited me over to hear what he had to say. “Now, you young fellows know as well as I do how difficult it is to do a job when you have no tools. But you might just about as well not have any tools as have poorly kept ones. “To get back to something I was just telling Jim—what use is an oilstone if it isn’t flat? And yet if Jim had continued at the rate he was going, he would soon have his looking dished, like the track in an autodrome! “You fellows have been with me a year and yet one of you is guilty of putting that very oil- stone back on the shelf with all the oil and dirt still on it. I want you always to put back your tools clean and in good condi- tion. It won’t do a bit of harm to clean your oilstone occasion- ally with kerosene. When a chisel has been nicked, don’t put it away as it is, for the chances are that the next time you want that very size chisel, you won’t have time to grind it up. Ii you put in a nick, take it out right away. Clean off the tool and put on a thin coat of oil occasionally to keep it from rusting. Don’t throw your edged tools into a chest or drawer full of other tools. “T might say something here on the sub- ject of grinding on a carborundum, or other artificial wheel. You know the speed at which one of these turn, and you know the heat that can be readily devel- oped by them. Be very careful not to draw the temper. I won- der if you know how little heat is required to (Continued on page 118) ‘ Mae s Two crimes against tools and a group of casualties. The saw has lost several teeth, the bit has been bent and the point ruined by too much pressure, the try-square blade has been used as a pry, the plane was broken by being dropped, and the other tools were damaged by similar abuse

Page 78

78 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Lamp-Shades from Wooden Bowls By Gladstone Califf Superintendent of Schools, Richland, Ia. OW to make an attractive shade is H a problem to be solved whenever a table lamp is to be constructed in the home workshop. Shades generally are made by covering a wire frame with silk or imitation the latter a 1%4-in. chamfer on two sides. The upright may be one piece or two pieces glued together. First plane the up- right so that it is 214 in. wide the full length of the piece. Find the center of one end, mark a line 1 in. on each side of the center and draw slanting lines from the opposite ends to these marks at the be used in place of the silk, if preferred, The standard of each lamp is walnut, and the bowls, which are maple, have been stained to match with water stain. Lamp No. 1 was given two coats of walnut water stain, 2 coats of white shellac, each coat being well rubbed, and then finished with varnish, the last coats well rubbed with pumice-stone and oil.

parchment. Far more unique and even less expensive are shades made as _ illustrated from wooden chop- ping-bowls. Such a shade may be orna- mented in various ways. Of the three lamps detailed below, No. 1 is made in the follow- ing way: Lay out two circles for the circular members of the base and cut them out with a circle or coping saw, keeping a short distance beyond the line. Smooth the edges with a rasp and sand- paper. The upright is part of an old table leg, but it can be made by hand by the method described in my article, ““Making a ‘Turned’ Spiral Pedestal,’ in the April issue of POPULAR SCIENCE MONTHLY. The small base supports are made accord- ing to the dimensions indicated. Before assembling the parts with screws and glue, bore a 3%-in. hole in the uprights for the wiring. The shade is a wooden chopping-bowl 15in. in diameter. A steel cabinet scraper is used to remove the rough places, both inside and outside, supplemented with a safety-razor blade. Fine sandpaper com- pletes the work of smoothing. The outside is stained and finished like the pedestal, and then the inside is enameled white to

a Y 50 <2“ r

gs _ — Va CHAMFER Details of two lamp-stands, a chopping- bowl shade, and an indirect-lighting fixture reflect the light. A fringe or beading is attached around the inside of the bowl with small tacks. Lamp No. 2 is even simpler to con- struct. Make the two square pieces for the base and cut the base supports, giving

Lamp No. 1 is shown at left, No. 2 at right, and No. 3 in the center top. Do this on the opposite side and plane down to the slanting lines. Repeat the operation on the remaining sides in order to complete the taper. Drill a %%- in. hole through the upright for wiring. The upright for lamp No. 3 was made from a discarded pedestal. It would bea simple matter to turn a similar stand if a lathe is available, and, lacking this, it costs very little to have a turning made. The base is 10 in. in diameter, with a l4-in. chamfer around the edge, and the four base supports are chamfered in the same way. The shades for lamps Nos. 2 and 3 are pierced chopping-bowls. First find the center of the bowl and draw two lines through it as indicated in the accompany- ing drawing. With a compass describe the four arcs shown. Then, to allow the in- sertion of a coping-saw blade, bore three 1%-in. holes in each of the four places to be cut out. Make the saw kerf or cut a slight distance from the line and smooth it with a rasp and sandpaper. The cut edges may be beveled, rounded, or molded to give the shade a lighter appearance, if the maker wishes to go to that trouble. Scrape and sand the bowl inside and out- side, as in the case of lamp No. 1. HE shades shown are lined with a double thickness of old-rose silk. This is done by cutting a paper pattern to fit half the inside of the shade and using this as a guide in cutting the silk. The lining is held in place with thumb-tacks and a strip of tape made of the same silk is sewed over the tacks. The tacks may be cut a trifle short, as the wood is hard. Parchment or oiled water-color paper may The other two lamps were stained and fin- ished by French pol- ishing. Another use for a chopping-bowl is to form a shade for an indirect light, as shown at the right hand of the accom- panying drawing. The bow! is finished in the same manner as that of lamp No. 1 and the ceiling plate is constructed as shown and finished to match the bowl. The brass chains are fastened to hooks on the inside of the bowl and hung from hooks in the ceiling plate. The electric wires run through the ceiling plate and down along- side one of the chains to the light, which is in the bottom of the bowl. A good finish for such a bowl is simply three coats of orange shellac, rubbed be tween coats, and several coats of thin wax. Hardware and electric fittings for the lamps can be purchased in any electric supply store. These lamp fittings havea brass rod that supports the shade; the upper part of this rod projects through the shade, which is held in place by a brass nut. Each lamp has two pull-chain sockets. If desired, silk cord may be used

‘to lengthen the chains.

Stand Holds Telephone Receiver while in Use O ALLOW free use of both hands while telephoning is the purpose of the inconspicuous stand illustrated. Glued to the wooden base is a sawed- out ring, which forms a cup for the telephonein-

This stand allows free use of the hands for | note-taking

strument. A block shaped as show? holds the telephone in place without any serews, and this piece also supports 4 rod, preferably of 14-in. aluminum wire, bent to hold the receiver.—J. G.

Page 79

ls 2rred. alnut, been Lamp water 1 coat | with with id. oil. lamps d fin- h pol- for a is to for an ; 8 right .ecom- g. The in the is that nd the yn and » brass - inside in the >S Tun along- which simply bed be in wax. for the electric have a le; the through e by a ll-chain be used ceiver h hands rpose of ted. . sawed- llows free hands for | king as show? hout any ipports # 1um wire, ~ Je HEN the garage door | swung open and Jackson’s HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 79 “Antique” Cabinet Cheaply Built of an “antique” china closet from pieces of lumber taken from an old reed organ. Qld reed organs may be obtained cheaply from music dealers, yet they con- I HAVE just finished the construction BACK By Rufus E. Deering stained before varnishing, but it was not necessary to use a filler as the surface was quite smooth with the original filling. that the dishes on the lowest shelf of the cupboard would not be visible. The bulk of the dishes are stored here out of sight, and the two top shelves left for the pret- tier dishes and glass. tain beautiful lum- per, usually solid wal- nut or solid oak. SHELF 9'4'WIDE GLASS Sena _ There are many fine ae 3-4 turnings and mold- | ings on them that FLAT MOLDING DOOR FRAME ; ioe iN J cannot be had in any © other way without GLASS considerable expense. 20°X25" The lumber is well SHELVES seasoned, often more than 50 years old, and it has been used just enough to make it suitable for devel- oping the ‘antique look” now so highly esteemed. The two-tone effect 4 Seen at present in vogue can be duplicated by covering portions of the panels in the cup- board with panels of _ ss 1 ERY MMM MO fra BRACE ON REAR LEGS 7 Le 10%: a ~*~ A | Rags ww || |FRONT ee scrollwork taken from K the old organ. The cupboard anel_ is Beautiful aged oak from an obsolete reed p Pp organ furnished most of the material for this antique looking china closet. The orna- tone; then the scroll- mental top, scrollwork and molding were work is placed over it taken from the organ; and finished in an- made by hand as described in the July issue finished first in one other tone. The scrollwork is fastened on by gluing it lightly on the back and nailing it in place with brads sunk with a nailset. As the cupboard was put together, the old varnish was removed from each piece with cabinet scrapers, glass, steel wool, knives, and sandpaper. The wood was By George A. Luers Automotive Engineer ear rolled into the alley, the paint glistened in the sunlight. Any one who did not know the car would have said it had just come from the paint shop. Those who knew Jackson and his car, however, were aware that the machine was three years old and never had been Tepainted. The difference in the appearance of similar cars after a year or more of service is so pronounced that every owner must appreciate the need of proper care and treatment ‘o maintain the original gloss and luster, Jackson had given his car the requisite attention. Normally, there are two natural ele- ments ruinous to the paint: Exposure to the heat and bleaching of bright sunshine, and the solvent action of rain and snow. One human element also enters into the Tapid destruction of the painted surface— the front legs were we Be Reh mony Be Re N+ Re Na tots i meet se The back of the cupboard was made by placing rails with grooves at the top and bottom. The ends of the back boards rest in these grooves. The frame for the door was adapted from a panel frame of the organ. The lower part of the door was paneled over so the tendency of the owner to wipe off the varnish with any available rag, regardless of grit, grime, or grease. To avoid these requires only a little care. Follow Jackson’s example and do not park your car day and night in the open street, or clean it with any old cloth. The paint is a film little more than .02 The legs were made of straight pieces of stock 30 in. long and 114 in. square. The two front legs were made in a_ spiral shape by a method of hand turning de- scribed on page 73 of the July issue of POPULAR SCIENCE MONTHLY. The two back legs were tapered slightly toward the bottom. To fasten the legs, they were allowed to extend up in the cor- ners of the cupboard and were screwed se- curely. The two back legs then were braced with three-cornered pieces to the back of the cupboard. The ornamental top and _ moldings were adapted from the organ material as shown, but this fea- ture could be varied in many ways, ac- cording to the ma- terial on hand. The moldings were all simple flat moldings 144 or 14 in. wide. The wood was given a shellac-wax finish. The whole cupboard, of course, might be built of new lumber, but it would be harder to give it the antique look that is so valuable in a piece of furniture like this. How to Keep Your Automobile Polished Wool necessary in. thick. which is a varnish or special lacquer, is a hard film and takes a high gloss. This film must be kept intact in order that the color paint under- neath will be protected and retain its brilliancy. The equipment to care for the paint and also the top and uphol- stery is as follows: The upper surface, 213-gal. wash pail Cheese-cloth Castile soap Chamois Sponge Whisk-broom Body polish Probably most car owners have these materials on hand, but it is to understand their proper use to obtain the most de- sirable results. Rubbing the body should never be done before it has been dusted off with the woolen duster to remove every particle cf grit. Hosing mud off the body preferably should be done by flushing and not with the force of the hose. Another method (Continued on page 102)

Page 80

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Constructing a Six-Inch Jointer By Frank N. Coakley N DESIGNING machinery for the | home workshop two points must be borne in mind. One is that the ma- chine should be as strong as its manu- factured brother; the other is that easily obtainable stock should be used as far as possible, to avoid the cost of having pat- terns made for castings. Both these requirements I have tried to observe in designing the 6-in. jointer for the home workshop shown in the accom- panying drawings. The entire machine is made of oak or other hard wood and standard parts that may be purchased at hardware stores and from dealers in ma- chinery. Even the scrap pile or junk yard may yield some necessary parts. These sources of supply I can safely leave to the ingenious builder. The side members of the jointer are made from oak plank 21 in. thick and of the width and length shown in the side view. Pains should be taken to give the various pieces a good finish wherever they fit together, and the holes that are to be used for bolts should be drilled smaller than the bolts. That is to say, the holes for the 9/16-in. bolts are to be }% in. in diameter so that the bolt can be driven through, making a tight fit. A heavy washer of good size is to be placed be- tween the wood and the nut wherever they come together to prevent the nut from digging into the wood. HE countershaft for driving the cutter is fastened directly to the bottom members. The bearings are standard 13%-in. bore by 254 or 234 in. long, se- eurely bolted to the bottom members. Each bearing is provided with a grease cup. The size of pulleys and other dimensions not mentioned hereafter will be found in the drawing. Care is to be taken. that all the bearings are in perfect alinement, which is always most important. The tables are made from steel plate perfectly level and smooth. To the bot- tom of these plates are riveted 214 by 214 5 WINGNUTS FOR CLAMPING TABLES ———— 14" —_—_—— by 14 in. angles, the rivets being counter- sunk on the upper side of the plate and smoothed off carefully. To the sides of these angles the wooden wedges are fas- tened with oval head wood bolts, the nuts being on the inside against the angles. The bottom wedges are bolted securely to the stationary members. This allows Most of the labor of hand planing is eliminated by using a bench jointer wingnuts for clamping the table in posi- tion, two being used for each table. Be- tween the two side members two sepa- rators are used for holding them in line and four 9/16-in. bolts serve for clamping. For the adjustment of the end table at the entering end of the machine, reference should be made to detail A. The separator just mentioned is used as a support for the flat bar, which is tapped to receive the adjusting screw. A 2 by 2 in. angle is riveted to the top plate and the hole for the adjusting screw is oblong or oval to allow the screw to move when the table is being raised or lowered. This adjusting screw is not shown for the delivery end, as it is seldom that this table is changed, but if it is thought advisable to put one on, the same material and method may be used. The fence is made from 14-in. steel plate 2 in. wide and 14 in. long. The ad- SEE DETAIL A SIDE VIEW Side and end views of the jointer and details of screw adjustment for elevating and lowering the table at the entering end of the machine. Two types of heads also are indicated, but it is advisable to buy these parts. This jointer is one of a series of small machines designed by Mr. Coakley, others being a combination bench saw, published in March, 1924, and a metal shaper, described in the June, 1924, number 2 TABLES-104 Xd PLATE Ip LG. SHANDWHEEL BSS L35 LG. és SCREW 20 T ; PLATE 2° WIDE S5LG 5 BOLTS DETAIL A FENCE X2ST-PL.I4 LG. ADJUSTMENT WHEEL FOR ADJUSTMENT ATTACHMENT x FRONT VIEW justment is obtained by using two 2 by» by 4 in. angles as brackets, both being provided with holes at the bottom so thy they serve asa hinge. One angle is rivete to the fence and the other is clamped t, the table with standard thumb-nuts, 4 slotted hole is provided to allow the feng to slide back and forth, as indicated j, detail E. The three holes in the botton, angle will give settings for two angles— 22% degrees and 45 degrees. Others may be provided by drilling holes in the neces. sary locations. The two bearings for the cutter heaj are standard bearings for a 11%-in. shaft. It is advisable to use bearings with remov. able bearing caps, as it may be necessary at times to remove the head. Two styles of heads may be used, on known as the safety head, shown at 8 and the older style of square head, at (. The builder will find either satisfactory and should select the one he is best equipped to make, no doubt that shownat C. It is to be remembered, however, that in many shops the old-fashioned squar head has been replaced by the safety head, as in case of an accident the latter cannot do more than take off a small slice fron one’s fingers, whereas the square heal has been responsible for many seriou accidents. F ONE doesn’t care to make the safety head, yet wishes to use one, it can le bought at a low price. This is, perhaps, advisable, because it is necessary to have this part of the machine run true and be in perfect balance. The head either may be keyed or fastened to the shaft with set- screws. If keyed, two short keys may be used—one driven from each end. They need not be larger than 3/16 in. square, but must be a good fit. If setscrews ar used, four are needed, equally spaced and set slightly into the shaft. The knives are another part of the ms chine I should advise one to purchase, not because they cannot be made by the amateur mechanic, but on account of the tempering and grinding. One can pur (Continued on page 112) DETAIL E ADJUSTMENT BRACKETS FOR FENCE 1 ENDLESS LEATHER BELT 13% FLANGED PULLEY Ye" COLD ROLLED SHAFT 8DIA.X 2% PULLEY-I000RPM- 1¥8 COLD ROLLED SHAFT 4°DIAK2'6 PULLEY Pd KNIFE-2 REQ DETAIL D BELITRY, Bee SQUARE HEAD DETAIL C

Page 81

serious safety can be orhaps, o> have and be or may ith set- nay be They square, WS are ed and he ma Se, Not by the of the in pur ENCE MFT POPULAR SCIENCE ‘MONTHLY $1 FREE—25¢ Book on Wood It Tells How to finish soft and hard woods. How to stain wood artistically. How to remove old paint and varne ish. How to secure @ beautiful enam- el finish. i, oe e Finishing Johnson’s Wood Dye comes in all sizes—half pints to gallons. Among the most popular shades are: 128 Light Ma- hogany 129 Dark Ma- hogany 127 Brown Ma- hogany 123 Dark Oak ee 126 Light Oak ae 124 Golden Oak —*t 110 Bog Oak einen: 131 Walnut JOHNSONS woop DYE FOR THE or Na. 123 Dark Oak 6c. ON & SOM, “The antag ater RACINE, Wis, USA or eg ot am If you have a hobby for making cabinets, furniture, radio boxes, etc., —you will find our Book invaluable. For, naturally, you want to give your handiwork a beautiful finish. Our Book gives complete instructions for finishing all wood—hard or soft, old or new. Tells how to make soft woods beautiful as hardwood. It is the work of experts—beautifully illustrated in color. covering capacities—includes color charts, etc. JOHNSON’S Gives Use coupon below. WOOD DYE (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 16 popular shades as follows: No. 128 Light Mahogany No. 125 Mission Oak No. 129 Dark Mahogany No. 130 Weathered Oak No. 127 Brown Mahogany No. 110 Bog Oak No. 329 Red Mahogany No. 172 Flemish Oak No. 120 Fumed Oak No. 178 Brown Flemish No. 123 Dark Oak No. 131 Walnut No. 126 Light Oak No. 140 Early English No. 124 Goiden Oak No. 180 Gray No. 160 Brown Oak 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. ' The Wood Finishing Authorities’ 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 and give you a copy of the Johnson Book. aap aaaealianst nag eerie emp cemnce ana a mye $. C. JOHNSON & SQN, Dept., P.S.M. 9, RACINE, WIS. £ i — , i SERV ae “The Wood Finishing Authorities’’ 4 ICE a DEPARTMEN (Canadian Factory—Brantford) * Please send me free your Instruction Book on Home a i Beautifying and Wood Finishing. I enclose 10c tog a cover postage and wrapping. a a ARTISTIC jy 3) Tener EOE UE OCC OCCT T t -t 4 wood. IME Fc orsr'5, 5 x. 5a. drat a's sin Peter Gola core aaa ee | - FI y hie E LO EET CECE E ETC Ce : Wa RN I i 82s 6g. o.oo hd worse mcm wal alana q 2 Oe 6 eee ee

Page 82

POPULAR SCIENCE MONTHLY Making the Most of cee Milling Machine By Albert A. Dowd Consulting Engineer " HERE’S a young fellow over there,’”’ said the foreman, ‘‘who gets my goat. Every time I give him a new job, he spends 10 or 15 minutes looking at it before he does a tap of work.” The superintendent smiled, as he ir- quired, “‘How does he do his work after he does get started?” “That’s the funny part of it,” the fore- man continued; “he makes better time on most jobs than any of the other milling-machine hands, and for that rea- son I can’t say very much to him. But it [] CUTTERS Albert A. Dowd HIS is the first of a series of note- worthy articles written espe- cially for POP- ULAR SCIENCE MONTHLY by Mr.Dowd,who has a national reputation as an expert on mackhine-shop practice. His next article is ““Machi ning Troubles.’’ cite a Ve R- Se TAP — =| eee he was going to doit. He set it up quickly and carried it through to completion rapidly, making no false moves. When you have a single milling job given you by the foreman, it isn’t usually the actual cutting of the metal that takes the time, but the finding of angle plates, parallels, clamps, and the like, and setting up the machine ready for the work. Even in high production milling processes, when fixtures are used for holding and locating the work, the setting-up time is an im- portant factor. In any kind of a milling job you have two problems to consider: First, to locate and hold the work on the table, and sec- The rod - end Lacking a con- above had to cave radius be milled with mill, Mr. a radius at B Dowd used the fixture below Fig. 2. For milling two keyways at once certainly does stir me up to see him stand over there by the window and stare at a piece of work as if hypnotized, while his machine stands idle sometimes for half an hour.” “Well, I wouldn’t worry about it, as long as he does his work properly,” said the superintendent, as he walked briskly away to another department. He made it a point, on his return in an 1D ‘if CLAMP hs TABLE $ Fig. 1. Radius milling with an end mill hour or so, to pass through the milling department again, and noticed that now the young man was busily en- gaged, and his machine was tearing through a heavy steel forging at a rate that ap- peared likely to produce re- sults. Out of curiosity, the superintendent looked up a few records in the cost de- partment, and found that the man in question was making more money on piece work } than any other operator in the milling department, al- though his rate was somewhat lower. Why? Just because he thought out his job be- forehand and knew just how nail Fig. 3. Supporting thin wall of a casting ond, to machine it according to require- ments. Every man who operates a milling machine knows that work must be held very rigidly in order to prevent ‘“‘chatter.” When work comes through a few pieces at a time and must be machined without fixtures, your foreman may cffer a sug- gestion as to the best method of setting up, but it is up to you to do the werk. If you do a little thinking before starting the job, you will find it a great advantage. You often get some job that appears simple at first glance, yet you may have trouble with it because you have not been careful in the setting up Old Bill Says HEN you have many jobs to do, the quickest and easiest way is to do only one at a time. The feliow who says, ““That can’t be done,” generally wakes up when he sees somebody doing it. _ if you want to change your luck, put a p”’ in front of it, and keep plugging. "The man who uses a monkey-wrench to hammer a ccld chisel doesn’t belong in any machine-shop. I'd rather have my shoulders to the wheel than have my back to the wall. Almost any one can do the easy work; chanic on the hard jobs. | Don’t forget to remove all burrs and sharp corners from your | work with a file, so that the other fellow won't tear his hands. | it takes a good me- —in other words, because you did not stop to think it out properly beforehand. I remember very well the first job I had when I started work in an automobile fac- tory in Connecticut a few years ago. The foreman gave me a blueprint cf the rod-end shown in Fig. 1 at A and told me that there were 60 pieces on which the radius, B, was to be milled and that he wanted the entire job by three o’clock that afternoon. The pieces had been ma- chined and nothing more was (Continued on page 9+)

Page 83

'.S aw ww eS SS ae os is" ve nd old ces yas he POPULAR SCIENCE MONTHLY The Book that shows | how to do it right! MA SQ8¢ nasbereite LAYING OUT WORK = DRILLING (selecting speeds and feeds, grinding drill points, Counterboring, etc.) ‘ : TAPPING (regrinding taps, removing broken taps, use and care of dies, etc.) REAMERS AND REAMING FILING HACKSAW CUTTING GRINDING (wheel selection, mounting, dressing, or e lapping, etc.) f LATHE WORK (care, indication, adjusting, lo- cating centers, setting tools, testing, turning, checking.) and’ HOW TO READ AND THE ADJUSTMENT OF MICROMETERS MILLING AND MILLING MACHINES’ She Book youve heen looking for | BITS AND. FITTING NG FITTING PISTONS ~~ PINS. Here it is—the Starrett Book for Motor Machinists dni Auto Repair- CYLINDER HONIN men; first and only book of its kind ever published. Over 200 pages of VALVE FITTING. data on the maintenance and repair of autos and trucks and when you FITTING. CRANKSHAFT AND -CON-ROD look it over you’ll say three loose quarters never brought more value. | ADJUSTING TAPPETS wae ° 3 > DECARBONIZING This Handbook has been prepared by authorities in the automotive THE ACETYLENE TORCH world. Written for the man in the shop. Profusely illustrated. Diagrams. CHAIN. DISCOUNTS. (how to. figure) Tables. Well printed. Bound in handsome red Athol-leather. Handy DEFINITION OF ELECTRICAL TERMS size (434 x 714’") for carrying in pocket. In every way Volume III of Tables Covering the Starrett Books is a fitting companion to Volumes I and II (The Decimal equivalents of Fraction of an Inch Starrett Book for Machinists’ Apprentices and The Starrett Data weuhs af diiicer matte ween toleaceg Book for Machinists) of which nearly 100,000 copies have been bought Peak ee by skilled machinists as well as those learning the metal working trades. Melting Points of Metals Piston Displacements ; : = one . ss Wire and Sheet Metal Gages If you work on a car this Starrett Book will pay for itself a hundred Wood Screw Specifications ° . - Ow to te. arburetor S$: times over. Get it for 75c. at any hardware store selling Starrett Tools. Antl-Preesing Solutions, ' If there is no dealer near you, send 75 cents and we will mail you a Maximum Power Required to Drive Machine, copy with charges prepaid. Whichever you do—ACT PROMPTLY. Feneat Anmdor Bel Bearings mule The first edition is limited and these practical handbooks will go fast. Grades of Grinding Wheels ‘ ° Grain Numbers Commonly used in various Write for the new Starrett Catalog No. 23 ‘‘W’’ describing wana CPezations xs over 2200 fine Precision Tools for Machinists, Auto- Rules for Figuring Tapers * p ics. Cutting Speeds and Feeds for Turning Tools Repairmen, Carpenters and Mechanics U. S. Standard Screw Threads oe Tap and Body Drills . Taper Reamers for Standard Taper Sockets THE L ° S. STARR ETT Co e Wrench Sizes for Bolts, Nuts and. Cap-Screws Continuous Drill Table + 7 The World’s Greatest Toolmakers Definitions of Symbols used on Wiring Diagrams- Manufacturers of Hacksaws Unexcelled ATHOL, MASS. HOW TO READ A MICRO The pitch of the screw thread the spindle C (See Fig. 10) is forty to1an ince" ution of the spindle, therefore, moves it ength oo )- 6644 MOTOR MACHINISTS Oh (So REPAIR MEN

Page 84

84 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY How to Scrape Metal Surfaces By H. L. Wheeler Machine-Shop Foreman LL bearing surfaces on high grade machinery must be scraped. We have only to consider the enormous number of machines turned out to realize how vast is the area of metal surfaces scraped each year in machine- shops. For this reason the art of scraping metals is an important branch of the machinist’s trade; and it is an art that cannot be learned merely by following set rules. Perfection is acquired only through patient effort and con- tinued practice. Machined surfaces rarely are abso- lutely accurate, except, perhaps, work that comes from the grinding machines, and even this, while appearing flawless to the naked eye, is not entirely perfect. Large flat or long parallel surfaces, whether planed or milled, are never quite true when they leave the machine. And where such surfaces are to function as a bearing for some other part of what is to be an accurate piece of mechanism, they a ae Fig. 1. (SNUG FIT) Fig. 2. Parallels and scraped test pieces used in the checking of milling machines must be scraped and the mating part must be scraped to them. This scraping process compensates for the errors left by the machine and incidentally leaves a smooth surface. Several attempts have been made to accomplish this work by SSS J AT a ea Me = - = 44! — = aT [*\ l am a / _ iLyg aa ENLARGED END VIEW CORNERS BELOW CUTTING EDGE TO PREVENT SCRATCHING * SPRING CLIP -----°" DETACHABLE SCRAP Be esos me Fig. 3. Convex scraper (exaggerated), a bear- ing scraper, and a detachable-blade scraper Scrapers for flat work usually are made from 34 to 114 in. wide and about 1/16 in. thick at the end or cutting point, tapering slightly for 2 or 3 in. to the heavier section of the body, which is from 3/16 to 5/16 in. thick. The highest grade of carbon-tool mechanical means, but up to the present time, success has not crowned the efforts of in- ventors in this field. Those who take up scraping as a specialty need have no appre- hensions of being crowded out of a job by the develop- ment of a machine to do the work. It is one of the few hand operations that. still baffles the ingenuity of in- ventive skill. In this article I shall de- scribe the few simple tools used and some of the con- ventional methods employed in the work. At A and B, Fig. 3, are shown types of scrapers com- monly used, the flat scraper for flat work and the half-round scraper for cylindrical work, such as fitting bear- ings. These vary in length and width and slightly in shape, depending upon the nature of the work and sometimes the individual fancy of the operator. Figures 1, 2, and 5, courtesy Brown & Sharpe Spotting work on a surface plate (at left), and a me- chanic demonstrating correct position for scraping (at right) steel makes the best scrapers— about 1.40 to 1.50 carbon. They should be almost file hard, or as hard as possible without having , tendency to crack or crumble at the edge. A detachable blade Scraper for finishing and light work jg shown at C. The scraper is fastened to the long shank by means of three pius and a spring clip. Opinion varies concerning the correct contour or shape for flat scrapers. Hold a machinist’s scale at an angle and let the end come in contact with a flat surface. Note how the whole width of the scale bears from corner to corner. Noy move the scale a short distance while bearing down on it. The corners have a tendency to drag or scratch, do they not? If a scraper is ground so that the cross section at the cutting end re sembles a scale, it inevitably will do the same thing. To get away from this ob- iection, the end is rounded slightly as indicated at A. It will be noticed that this scraper has still another feature that enhances its cutting ability over the strictly fiat scraper, which merely is rounded at the end. The cross section at this point is DIAGONAL DIAMOND Fig. 4. Types of frosting used to ornament surfaces previously scraped to a true plane slightly convex. This raises the corners from the surface even when it is held ina horizontal position. It will be seen that this method of grind- ing makes it practically impossible for the corners to dig in at any angle. The endis ground diagonally from opposite corners and it is given a slight back rake—about 114 degrees. This gives to the cutting edge a free shearing action, which in- Fig. 5. Scrap- ing a spindle box and the face of a mill- ing - machine column creases the speed of the cut and reduces the resistance 0! the cut on the operator's hands and arms. An exam- ination of the line drawing clearly shows the form for grinding, which may be ac complished to best advantage on a soft, wet grindstone. It should be emphasized, however, that the convex form is not absolutely esset- tial for a flat scraper. Some may prefer the perfect flat. In making the convex, lr deed, it should be very slight, just enough to make the cutting edge in the center with about 1/ in. flat. In the drawing this has been exae gerated for the purpose @ illustrating the idea. The center is actually only from (Continued on page 89)

Page 85

POPULAR SGIENCE MONTHLY For Assembling or Repairing Your Own

Here are the Files you need to simplify the job and assure proper results. An 8" Round File--for A 10’ Flat File---for enlarging holes in panel smoothing panel edges boards. and beveling. -. An 8" Cabinet File---for . ~ prec finishing ends and. edges ———_ sagpe sion — - | of wooden cabinets. ; woe. CONES ment a points. plane ie we A 10’ Half Round Bas- ’ g ¢ tard File---for smoothing A 6" Flat Bastard File--. _—— 4 peep holes in panel. for miscellaneous work. eld ina

; ~ > - Don’t try to make one File do it all. It f grind. . i won’t. But for every filing requirement, for the (‘Ge ‘ Ge there’s a NICHOLSON File, which in dis Reg e ° pee very an SS 1e center : . In the en exag- rpose ol ». The ‘ S. nly from is “r ’ “id E “4 - = (TRADE MARK] ¢ 8) . 3 ati

Page 86

No. 226 Ball Anvil Attachment No. 500 Combination Bevel \=C J UL No. 749 Cast Iron v Blocks and Clamps CW BROWNé SHARPE kit You should see these tools. They’re beauties. A mechanic would enjoy handling them, for somehow he would in- stinctively realize that they ‘‘feel’’ right. The design, balance, clean-cut graduations and immediately recognized utility are features by which the skilled mechanic knows them to be tools made by master workmen. Furthermore, the name and trade mark of Brown & Sharpe assure him of the accuracy and durability expected of Brown & Sharpe Tools. Stop at your dealers, see and handle these tools. You, too, will feel their ‘‘personality,’’ and will be proud to have them in your kit. Vv a Brown & Sharpe Mfg. Co. A Las « sr X Providence, R. I. a \ The New No. 29 Small “ @ Tool Catalog The new size catalog is most convenient, slips right into the pocket, easy to handle, and. above all, it lists tools that are of in- terest toevery mechanic SEND TODAY FOR YOUR COPY © OF THIS CATALOG BROWN & SHARPE TOOLS Standard of the mechanical world BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY | oilstone. How to Scrape Metal Surfaces | (Continued from page 84) .010 to .015 in. higher than the corners. After grinding, the scraper is honed on ap The oilstone rests on a bench and the scraper, held in a nearly vertical | position, is rocked back and forth over | | the oval edge a few seconds with pres. | sure to give it a keen cutting edge. [| the scraper is made of good steel and js| properly tempered, it will last a long time | | without regrinding and only an occasional | rubbing on the stone will be needed. Before scraping a job, the work must! be spotted. This operation reveals the true condition of the surface, indicates the high and low spots, and serves to guide the operator. The high spots must be brought down to the same plane as the low spots. Several different materials are used for spotting. On the coarser grades of work red lead and oil may be used, but for very fine work Prussian blue is the best ma- terial. When using Prussian blue, only a very small quantity is required and in all cases it should be used sparingly; a piece the size of a pea will cover a very large area. Another point to bear in mind when applying any spotting material to | the plate is that it should be distributed complete your evenly. Thick and thin spots will result in a false bearing. N SOME cases the plate is applied to the work and in others the work is applied to the surface plate;. the results in either case are the same. This is governed by the weight of the job. Where the work is of a light character, the usual practice is to apply the piece to the plate. Before marking or spotting the work, all dirt and chips must be removed and the plate must be free from any dirt or grit. The piece is then placed upon the plate in contact with the surface to be worked upon. It should be moved around and turned in several directions on the plate without applying any downward pressure other than the weight of the piece, as in Fig. 1 at the left. At the right of that illustrated is shown the correct position of the mechanic and the method of holding the scraper. Considerable pressure sometimes is re quired on the scraper to bring a job down to the proper surface within a reasonable time; this depends in some degree on the size of the job and the condition of the surface as left by the machine. It 8 understood, of course, that the push stroke is what takes the metal off the high spots. In some classes of work, such as scrap- ing long machine beds and the ways of lathes and planers, there is a peculiaf freakish tendency of the castings to warp and twist after being machined. It is the custom of some companies to rough of 4 number of castings and pile them out 0 doors for several months for ‘‘seasoning. This relieves the stresses and _ strains Even with this careful process there § often a slight warp or twist in the casting when it comes to the scraper and this has to be taken out with a heavy scraper ant lots of elbow grease. Extra heavy work is set up on the floo (Fig. 5). The surface plate should be —" (Continued on page 88)

Page 87

POPULAR SCIENCE MONTHLY Ces mers, On an ench Ttical | over | pres- | e. If| ind js | r time | sional | must | Is the es the guide ist be is the ed for work r very st ma- only a | in all 1 piece r large mind rial to ibuted result | to the ipplied either ned by vork is ctice is - work, ed and dirt or yon. the . to be around on the ynward of the 1e right correct method s is re b down sonable on the of the It is e push “1 All out-doors invites your Kodak 3 scrap- vays of yeculiat to warp t is the re Autographic Kodaks $6.50 up oning. strains. there is casting this has per and wet | Eastman Kodak Company, Rochester, N.Y. 1% koist ciy ould be

Page 88

Take any user’s advice and buy a Remington Portable Remington Typewriter Co. 374 BROADWAY, NEW YORK . Branches Everywhere Resincton Tyrewrirrr Company or Canapa, Limitep Main Office: 68 King Street West, Toronto We believe we make the best typewriter ribbon in the world—and its name is PARAGON Durability and Reliability The Remington Portable has won the endorsement of the world by its unequaled durability and reliability. You can count on it for years and years of faithful service. ‘er Compactness and Portability The Remington Portableis themost compact of all writing machines, When encased it is only 4 inches high, so it can be tucked away in a desk drawer or bookcase. It weighs but 11 pounds. It carries its table on its back, which makes writing easy and convenient in any place or po- sition, even on your lap. Maes: raae | 2 Four-row Standard Keyboard For fifty years the four-bank key- board has been recognized as stand- ard. The Remington Portable has al- ways had the standard keyboard, with four rows of keys—no shifting for figures—exactly like the big ma- chines—the keyboard universally adopted by business as the best. Keyboardsinthirty-twolanguages and for every occupational require- ment, Ss Ease of Operation You will be surprised how quickly you can master the operation of the Remington Portable. The four- row, standard keyboard, and the simplicity in design and construc- tion of the entire machine make it incomparably easy to learn and to operate.| Beautiful Work Always The writing of the Remington Port- able is exceptionally beautiful. Even a beginner turns out work that is a revelation. This, of course, is due to the fine construction of the machine, and its habit of al- ways being in perfect alignment Universal Service Wherever language is written—on the six continents— you will find Remington service, for there are over ‘00 Remington offices through- out the civilized world. A Reming- ton Portable owner knows that wherever he goes Remington ser- vice is near at hand. This feature is one that no portable typewriter buyer can afford to overlook. alte ae On every count—whether work, wear or service—the superiori- ty of the Remington Portable is decisive. Sold by over 5,000 dealersand Remington branches everywhere. You can buy one on: easy terms, if you wish. Write for our illustrated, **For You—For Everybody.” Address Dept. 67, BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY | on planers. — A. L. Springs Save Time in Clamping Duplicate Parts HE simple ex- pedient of using springs under work clamps, as illustra- ted, has resulted in cutting down ma- terially, in one shop, the time of setting up repetition work CLAMP BOLT Support Steadies Long Work in Machinist’s Vise | . * Y aoeanag working on long material at the vise, it is often a considerable aid to use a support made as shown. This is machined from a piece of flat stock of the desired length, one end being a turned down to Si ; any suitable dian- : ‘ eter and fitted with a sliding fork or rest. In this way the end of the work may be prevented from sagging. This saves shifting the stock in the vise SLIDING LARGER THAN VISE SLIDE) om pt Vise steady-rest How to Scrape Metal Surfaces | (Continued from page 86) placed at a convenient height for the operator to use or hung on a chain hoist by a special grapple hook. When the plate is rested face down on a bench, it never should rest directly on its finished surface. A special board having leather or felt pads should be provided, or it may rest on another surface plate, face to face. Scraping bearings also is illustrated in Fig. 5. In this work the interior surfa of the bearing is scraped to fit the spindiz. Sometimes a special mandrel is made and used as a master plate and in others the spindle is used directly for the bearing for which it is intended. In Fig. 2 is a group of special test pieces and parallels used for checking scraped angular surfaces, such as the ways 0 lathes and milling machines and the V's of planers. Closely allied to the scraping of metal surfaces is the producing of the orns mental appearance known as frosting. This is an added refinement used whet time and expense warrant in order t decorate the surfaces. The principal figures seen on frosted machine surfaces are indicated in Fig. 4. The crescent pattern sometimes } varied by adding a second series 0 crescents, so that the surface is mottled with what appear to be full circulat marks. In either case, the scraper oscillated right across the surface to form a whole string of crescents at one time. _ In forming the straight and diagon# diamond patterns, the mechanic draws the scraper toward him to make of broad mark and then passes it sideways to the right a trifle, preparatory to draw: ing forward again. To learn to do this is mainly a matter of practice. so often.—F. N.C! i E far a game the fr Succ Not on of resy tinctly Maste of rad phone

Page 89

POPULAR SCIENCE MONTHLY k in ial at rable This ck of ongth, being ae diam- | d with rk or S way > work | rented . This ig the e Vise| he Bring In Stations on the = You Never Heard Bef eke u ever ear erore leather it may EACHING out through the ether to other loud speakers—because it is a pre- 0 face. —‘fishing’” for new stations in sion instrument of the highest order. ted in far away places—is a most thrilling Cores are of specially selected steel, chemi- surfare game. To many, it’s more than half cally treated to rust proof them. Pole faces pind.e. the { t omit hens are ground to an accuracy of one-ten-thousandth de and oe = radio receiving. of an inch of each other; and the specially treated a a ee <a Success in this absorbing venture requires steel diaphragm is gauged toa half-thousandth of instrument of radio. Volume rs not only a good receiver but a headset capable an inch. All parts are accurately measured by without distortion. Connect pearing of responding to faint signals clearly and dis- the most delicate recording instruments known as you would headphones. ‘ g ty z hee! : ; No batteries required, no - tinctly. Such is the new supersensitive Music to science. Each finished pair must vibrate adjustments. 14-inch model ; pieces Master Headset. ‘‘It’s equal to another stage fully, freely, evenly and without rattle over the for the home—$30. 21-inch craped of radio frequency,” one user said. entire scale of audible frequency. modeasn concerts and danc- ays of ht Music Master Headset is to other head And it is a handsome, comfortable set, ; he V's phones what the Music Master Reproducer is sanitary and enduring. Price—$12. ill Ask Your Dealer To Let You Try One . orna- ie {Music Master Corporation © vate 10th and Cherry Streets urfaces Chicago PHILACDELFHIA Pittsburgh as[er Music Master Loop Aerial is equipped with calibrated dial; covers the entire band of HH E. A D S E broadcasting wave lengths. I Price—$10. Makers and Distributors of Liigh-Grade Radio Apparatus mes i ries of nottled circular aper is to form time. iagonal draws ke one ideways o draw: do this

SRTTVSSeTUUeseCeaverecaceeceaa:

a at

Page 90

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY ‘tite Bench Vise “161 Price, $2.40 of inact Tt + a A small vise— with jaws like a bulldog’s VISE is judged by its jaws. They’re “the works.” Find a vise with jaws that meet flush and true, won’t wobble or loosen, hold with equal strength at all points and with the tenacity of a bulldog— and you’ve found a vise that will be a real helper for all the years to come. This Goodell-Pratt Vise is that kind. Clamps to any bench of less than 14-inch thick- ness. Operated by an accurately cut steel feed screw. The two steel guide rods hold the jaws rigid. All parts carefully fitted—the final operation being the close machining of the jaws to make them meet with absolute accuracy. Steel parts are polished. Iron parts beautifully finished with enamel, baked on. Width of jaws, 2 inches; jaws open, 2 inches; weight, 3% pounds. Other tools for the small workshop In the Goodell-Pratt family of 1500 Good Tools are many other such tools made specifically for the small workshop. The catalog shows them all. Write for it. Just ask for Catalog No. 15. GOODELL-PRATT CO., GREENFIELD, MASS., U.S. A. © Soolionithe Makers of Mr. Punch Simple Jig Prevents Breakage in Driiling Plate Giass IN DRILLING plate glass for attaching | windshield wipers, special inside Spot. | lights, and similar purposes, the simply | made drill jig illustrated has proved gy. | cessful in preventing breakage. It con. | | sists of 2 blocks of wood, 2 small pieces of ! WOOD WINDSHIELD _- STRAP IRON | The drilling tool is guided by a wooden block clamped firmly against the glass strap iron, 4 wood screws and 2 clamp screws. The jig will serve with whatever type of tool is used for drilling the glass. Usu- ally the tool is a file or a specially hardened steel drill kept wet with turpentine and camphor, or else a brass tube with an abrasive of turpentine and emery powder. | Roller Guide for T-Square O HOLD a T-square against the left- hand edge of the drawing-board at all times is the object of the device illus- trated. This is especially intended for use on a _ large DRAWING-BOARD ; drawing-board not ANGLE ON equipped with an BOARD ordinary _ paralle! rule attachment. A bent plate somewhat. shorter than the length of the T-square head is fastened securely to the head. This plate carries a pair of wooden rollers. The rollers run against a track made of a brass angle which is fastened to the under side of the board parallel with the edge. Keeps T-square head against drawing-board Extension Blocking for Planer GREAT many of us know how ag- gravating it is to have a job blocked and clamped on the planer bed only to have the blocking slip on gs apr PSL erANDARD | the first stroke. HEAD OF” WASHERS Pp A good way to prevent this is to make a pin with a large head, provide the clamping bat with a hole through which the pin will mel pass, and use standard washers betwee! the clamping bar and the pin head to act as spacers. Much time can be saved by He using a set of these clamps in conjunction $7 Ordinary washers are used as spacing blocks | with a keg of 1- or 1 14-in. washers. How to Use a Universal Dividing Head, ocp, is a Better Shop Method article that — will appear shortly. a

Page 91

POPULAR SCIENCE MONTHLY e left- ard at > illus- ed for large rd not ith an aralle! ment. plate shorter gth of e head >curely _ This Pe 6 a pair li oa = Id Pa A10-year-old pledge More than a million and a half Brandes Head- sets and Table-Talkers are today doing valiant service! With each sale this time-tried guarantee assumes new strength and meaning. It is an old pledge that bespeaks the unlimited confidence of the manufacturer in his products—a confidence based on the continued acceptance of Brandes products by an alert public. 5 run angle, of the ANDARD | \SHERS ‘s are blocks ) ng bar ~ y/ 4) V4) in will LB Fe ye! =F etween i. oA —_- + 8 | to act perior site “od ved by | Matched Tone tion | Smo Li Radi 5 Hes, | CCBrandes Inc..1924 O NOW in lO

Page 92

Henry.

an unrelated local unit. is enjoying the benefits.

ancne Bell System laboratories speech sounds are recorded on the oscillograph with a view to their scbsequent anatysis The service of knowledge The youthful Alexander Graham Bell, in 1875, was ex- plaining one of his experiments to the American scientist, Joseph He expressed the belief that he did not have the necessary electrical knowledge to develop it. “*Get it,”” was the laconic advice. During this search for knowledge came the discovery that was to be of such incalculable value to mankind. The search for knowledge in whatever field it might lie has made possible America’s supremacy in the art of the telephone. Many times, in making a national telephone service a reality, this centralized search for knowledge has overcome engineering difficulties and removed scientific limitations that threatened to hamper the development of speech transmission. available for all the Bell companies inventions and improvements in every type of telephone mechanism. It is still making This service of the parent company to its associates, as well as the advice and assistance given in operating, financial and legal matters, enables each company in the Bell System to render a telephone service infinitely cheaper and better than it could as This service of the parent company has saved hundreds of mil- lions of dollars in first cost of Bell System telephone plant and tens of millions in annual operating expense—of which the public

> You Can Also i Charge“B” Batteries - © At Home.

Th APCO “RB” Battery Charger is a worthy ally to the successtul APCO Charger for ‘tA’ batter Renews any 24 to 48 volt wet “B" battery in ten hours—with- out disconnecting set It’s noiseless, clean and as easy to hook up as an electric iron Complete with wires ready to use, $10. Write for interest. ing circular and nearest dealer's name,

APCO MFG. CO., Baker St.. Providence, R. 1.

“And am able to WEEK. Could do more only I do not ‘\\put in much over half time. Person- ally I think it is the easicst sold ar- ticlo I ever handled as it has meri’ and is a nocessity,”” says L.R. Gra- \ bam, Iinois, A. H. Robey of th,

can pane W.Va. made over $500 in onc mon nk DePries has been with us six them Magy 8 —verages over $150 a week. Hun- dreds of our men making $60, $75, $100 a week. Wo need more men to fill unoccupied territory. Hun- dreds of prospects makes selling easy , schools, stores, factories, shops, farms, homes, auto and truck owners, hos- _. Single sales bring big commissions. Largest concern of d in world. Write quick about this position. THE FYR- 198 Fyr-Fyter Bidg., Dayton, O.

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

| small hole in work chucked in a bench | CHUCK | to use a hand drill holder that is inserted AMERICAN TELEPHONE AND TELEGRAPH COMPANY | AND ASSOCIATED COMPANIES BELL SYSTEM One Policy, One System, Universal Service | with a closed end.

| small cost, and it is suitable for taps, drills, counterbores, reamers, and various other Telltale Aid in Setting Work for Taper Turning FOB setting over a lathe tailstock fo cutting tapers, the simple telltale A pier of machine steel 5g by 1 in. and ae SiC ’ ake a finger made of }¢-in. thick sheet steel pivoted o, After the spots are turned on the wor for the large and small diameters of the taper, the finger is placed in the tool. post and the tail. stock is set over until the finger just touches each turned spot, the carriage being run back and forth.

Lathe telltale

Tailstock Holder for Light Drilling on Bench Lathe ON THOSE frequent occasions whe it is desired to drill a center or a lathe, the usual practice is to remove the part and do the drilling on a drill press, One way to avoid taking out the work is SPINDLE, mam, Sag, SNUG FIT—\\\ Fr

— LATHE CEN A ring that slips over the tailstock center holds centering countersink or small drill between the work and the tailstock center. This holder consists of a grip ring knurled on the edge and drilled in the rear face to fit snugly over the tailstocl: center, so that the rear face of the ring bears against the spindle. This insures the ring’s being located centrally to the work. Screwed into the front face of the ring isa chuck for the centering countersink or small drill.

Diagonal Pins Hold Tools in Socket of Unusual Design TOOL socket that differs from the conven- tional type can be ASSEMBLED SOCKET

made inexpen- sively as __ illus- trated. It consists of a threaded holder and nut

Two diagonal holes are fitted, as indi- cated, with pins that are forced ; against the shank of the tool when te nut is tightened. For some purposes 4 single pin is sufficient. } For use in lathe or drill press, <his form of tool can be made up at comparatively END NUT (CLOSED) The socket and cross section, showing pins cutting tools.—G. A. L.

— Testin and oe ways, I cl of conven or 8 in. the cut ar in a horiz section, t light so a to a min would be it has bee Checki vertically

Page 93

tale ieee ut 5 ager d or york the er js ool. tail- Over just ach the vher or a ench > the TESS, er ill arted nter. ring rear nter, pears - the vork. y isa k or i iy | | arecut. A ring of The washers | the tool on top and | connected with the BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Testing Alinement of Lathe and Accuracy of Square Q DETERMINE accurately if the live spindle of a lathe is true with its ways, 1 chuck and turn a piece of metal of convenient diameter for a distance of 6 or gin. If the diameters at both ends of the cut are equal, then the spindle is true in 4 horizontal plane. In turning off this gction, the last tool cut must be very light so as to reduce the wear of the tool to a minimum. For greater accuracy it would be well to grind the surface after it has been turned. Checking the trueness of the spindle vertically in relation to the ways, an in- The special test piece used for checking a lathe spindle and testing a square dicator is placed in the toolpost and traversed beneath the turned surface. | Lack of movement of the indicator shows that the lathe spindle is alined correctly. This same piece of stock can be used to test the accuracy of a square. First turn a conical center in the end of the metal; then bring the tail center into the turned center in order to true the tailstock and spindle. Now form a narrow flat edge on the end of the piece and place it on a sur- face plate, as shown. A square, or any other right-angled tool, can be tested very quickly in this way.—JAMES F. HOBART. Tool for Cutting Washers \ ASHERS of any desired size may be cut rapidly from rubber, fiber, felt, or any material other than metal with a tool made as shown. Between the cutting edges is a recess that contains a ring for ejecting the washers as they are ejected the same diameter cabninatioaliy is placed outside inner ring by Means of two studs. These studs carry springs, so that each time the spindle is raised ~ the washers that EDGES have been cut are automatically forced out of the tool. Tool steel should be used. The edges may be resharpened without altering the size by grinding the bevel. The shank of Y EJECTOR RING the tool is held in a drill chuck or made | with a taper shank, as preferred. The material to be cut is placed on a |: board so that the cutting edges will not | « be dulled.—H. W. We've Made You A Unique Shaving Cream Will you please accept a test? By V. K. CASSADY, Chief Chemist Gentlemen: Here is a Shaving Cream which millions are discussing. It does five things which men desire in a surpassing way. The history is this: Palmolive Soap, through its effects on the skin, had become the world’s leading toilet soap. We desired to bring men those same effects in shaving. But men, we knew, wanted other results. men to tell us what they wanted most. Then we worked 18 months to meet their requirements as no one else had done. We made up and tested 130 formulas to attain the utmost in a Shaving Cream. Five astonishing results 1—Palmolive Shaving Cream multiplies itself in lather 250 times. 2—It softens the beard in one minute. 3—lIts lather maintains its creamy fullness for ten minutes on face. 4—The extra-strong bubbles support the hairs for cutting. 5—The palm and olive oil content makes the cream lotions like in its effect. So we asked 1,000 The result has been a sensation. To add the final touch to shaving luxury, we have created Palmolive After Shaving Talc—especially for men. Doesn’t show. Leaves the skin smooth and fresh, and gives that well-groomed look. There are new delights here for every man who shaves. them to you. Clip coupon now. THE PALMOLIVE COMPANY (Del. Corp.), 360 N. Michigan Ave., Chicago, Ill. PALMOLIVE Please let us prove 10 SHAVES 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, Wis., Dept. B-846. Address _ for residents other than Wisconsin, The Palmolive Company_ (Del. Corp.), 360 North Michigan Avenue, Chicago, IIl., Dept. B-846.

Page 94

It’s worth while spending a little time, when you pick a plier for your kit. Ask your hardware dealer—he knows a lot about tools. And if it’s quality pliers you buy, he will probably tell you to take a leaf out of the professional electrician’s book and buy Klein’s. There is sixty-seven years of experience built into every Klein plier — sixty- seven years of manufactur- ing only quality tools! 3220 BELMONT AVENUE CHICAGO, ILL. BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

| | | Making the Mest cf Your Milling Machine (Continued from page 82) to be done except to mill this radius. It was eight o’clock in the morning and I had only six hours in which to machine the 60 pieces, but this looked easy enough, as I only needed to do 10 pieces an hour. I went to the tool crib and asked for a coneave radius mill with 14-in. radius, but after looking all over the crib, the tool man said he had nothing but a 5/16-in. radius mill, so I was stuck. After a few minutes’ thought, I looked up a block of cast iron of the form shown at D, turned up a stud, E, and inserted it as shown, then clamped down the block on the table of the milling machine. I centered the plug with the spindle as indicated. Next, I threaded a 5/16-in. rod 12 in. long for a handle and put in a 1-in. end mill (F). Screwing the handle C into the rod-end G and placing the latter on the stud E£, it was an easy matter to move the handle back and forth in the direction of the arrow and thus generate the radius re- quired. As a matter of fact, I had the 60 pieces done a few minutes before noon, although some of them were a trifle rough. I touched them up with a file and removed the burrs, finally making a good job. When I took thé work to the foreman, he wondered how I had done it so quickly, and asked where I got the radius mill. I took him over to the machine and showed him the rig I had used. It developed later that the foreman knew there was no radius mill of the right size in the tocl crib and had given me the job purposely, to see how I would le make out. oa % FEED Incident- AN See ally, I re- <5 AS ceived an RY --+---4 : : Pinos Ss increase in pay the next Sat- urday, pre- sumably for the in- genuity displayed. The or- dinary milling-machine operator seldom stops to think that it often pays to take a little more trouble and set up two or more pieces atatime. Frequently they may be

JAW

VISE

TTITITITT, Fig. 4. Milling a slot | machined almost as quickly as one could | be done.

Take the example shown in Fig. 2. There were 50 shafts (A) in which keyways were to be cut as at B. Many operators would set up one piece at a time and clamp it in the usual way against a parallel in the T-slot, but by using blocks as shown at C and a single clamp between the pieces, they could be set up almost as rapidly and located as positively. Then, by using two cutters on the arbor, the pro- duction almost could be doubled. A thin casting is always hard to hold and difficult to machine. ‘‘Chatter”’ is (Continued on page 95)

—= Start with The; Early Training You can bring up machines to work fast and profitably, much as you build up good workmen, By using a counter and getting a record, you can check up the out. put and GAINS in output as you perfect your machine mechani. cally. You'll develop better operating methods—and a better operator at the machine. Each new step, as it counts in results, will be measured for what it’s worth— by your COUNTER The small Revolution Counter be- | low registers one for a revolution of a shaft, recording a machine operation, or product. Though small, this counter is very durable; its mechanism will stand a very high rate of speed, making it ™. especially suit- i able for _ light, fast-running ma- , chines and most adaptable to ex- perimental work.

tC™

Rotary Ratchet Counter, to register reciprocating movements of small ma- | chines, also $2.00. The Revolution Set-Back Counter below records the output of the larger machines where a shaft-revolution indi- cates an operation.

Sets back to zero from any figure by | turning knob once around. Supplied with | from four to ten figure-wheels, as re- | quired. Price with four figure-wheels | as illustrated, $10.00—subject to dis- count. Cut less than one-half size. Set- | Back Rotary Ratchet Counter, to record reciprocating movements as on punch presses, $11.50 (list). Everything you need in a counting device goes to make up the 80-page Veeder booklet. You’ll enjoy see- ing a copy; gladly sent free. The Veeder Mfg. Co., 44 Sargeant St. Hartford, Conn.

If run backward | the counter sub- | tracts. Price $2.00. (Cut 4-5 size.) Small | ——

Page 95

—— 1eir ng nes to | uch as n. tting a 1€ Out- as you | >chani- erating erator N step, vill be orth— Wu ter be- | olution machine Though durable; hanism da very | ate of aking it ly suit. r light, ling ma- nd most | le to ex- tal work. ackward | iter sub- ) Small | register all ma- ‘ounter e larger | on indi gure by lied with , as re- e-wheels to dis- ze. Set- o record . punch in a to eder see- | free. Co., , Conn. — es | Making the Most of Your Milling Machine (Continued from page 94) very apt to develop on this kind of work. If you clamp the piece too strongly, you are very likely to spring it out of shape and if too loosely, it will chatter or change psition during machining. Take the piece shown in Fig. 3 for ex- ample. This is a thin bronze casting, A, which is to be face milled on the flange B. We first set up this piece by means of set- serews in surrounding angle plates as in- dicated and started the cut. Before the mil] had traveled 3 in., a persistent chatter developed, at which time the machine was stopped and setscrews tightened again. Before the first piece was completed, we had to stop the cutter four or five times and tighten the set- screws. We were using cone - point screws and changed these to the cup - point variety, which im- proved the situation slightly, but we were obliged to use a very light feed and high speed to pre- vent chatter. This made the operation slow and some distortion was apparent. The trouble finally was overcome by i using wooden blocks and jacks at C and | D opposite the setscrews. By this means vibration was overcome and the screws could be tightened sufficiently to hold the work without causing distortion. A prin- ciple similar to this often can be used to advantage when holding thin or fragile work, When you have occasion to cut a slot through a casting or a forging, as shown at Ain Fig. 4, you are very likely to pro- duce a result as shown in exaggerated form at B, in which the sides have sprung away from the cutter during the process of ma- chining. If you put the piece in vise jaws, as shown at C, and mill through the slot lengthwise of the jaws, trouble will be caused by the cutter’s binding and giving an inaccurate slot when finished. If you cut crosswise of the jaws, you will have a result similar to that shown at B. Several solutions are possible in a prob- lem of this kind. If you have only one piece of machine, you can take a cut through the center first and then a light finishing cut on both sides, using a rather high speed and fine feed. The operation can be done with a single cut by using special jaws as shown at D, high enough tosupport the sides well and obtain a good | 8p to prevent spring. If there are a | number of pieces to be machined, this is, % course, the best way to do the job; but a only a few are to be made, it would ardly pay to make up jaws specially. SPINDLE BUTTON By Cc A ) Qe JIG BODY ie sy Fig. 5. Locating holes with sleeve and button ] i 1 jig work, care must be taken in setting (Continued on page 96) ei When using a milling machine for the | accurate boring of holes, as often required BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Work on your radio with “YANKEE” RADIO TOOLS They make radio construction easy, save time, do better work. It’sfun! You just move handle of “Yankee” Tool Holder back and forth on ratchet move- ment. The tool countersinks, reams, runs up nuts, drives screws. Attachments for these opera- tions fit holder. A touch on Ratchet Shifter gives you right- or left-hand ratchet; or rigid adjustment “Yankee” Radio Drill No. 1431, capacity 9-32 inch, is just right for radio jobs. In addi- tion to use on your radio, you will find these tools handy for general use around the house. “YANKEE”? Radio Tool Set No. 105 Price $3.25 All these attachments fit “Yankee” Ratchet Holder: Blades—one for long reach into box, between wires, etc. —one for small screws on dials. —one for heavy screws—putting up aerials, etc. Countersink—for heads of screws. Sockets—(two) cover all small nuts. Reamer—for enlarging holes in panel. Wrench—one end, square or hex. Other, hex for jacks. Wire Bender—for bending wire and making loops. ‘“YanKEE”’ Drill No. 1431 Price $3.00 4 1o 1 gear for speed. Special Radio Chuck to take largest drill usually supplied with radio drill sets. Your dealer can supply you ““Yankee’’ Tool Book Free on request Nortu Bros. Merc. Co., PHILADELPHIA, U. S. “YANKEE TOOLS Make Betly Mechanics *“*YANKEE” sg ES Radio Set No. 105 A. “ JIuNVA wWaMNVA, | ZIANWA LL. **“YANKEE” Radio Drill No. 1431

Page 96

96 ‘ ili hen ams Shaving Cream SA cy designed tor speed If you like to make race track speed in the morning, Williams Hinge-Cap will appeal to you. Slippery fingers can't drop it. Carelessness can't lose it. For the cap’s hinged on. It simply can’t come off. As for the shaving cream, it was designed especially for men with wiry beards and tender skins. Williams works up into a rich, creamy lather almost instantly. And as the razor glides across your face you experience a new sensation. Each stroke is lubricated. Razor friction is removed. And when the shave is over, your face feels clean, cool and delightfully refreshed. Try Williams tomorrow morning. Large size, 35c. Double size, soc, con- taining almost twice as much cream. Tue J. B. WittiamMs Company Glastonbury, Conn. The J.B. WilliamsCo.(Canada) Ltd.,St.Patrick St.Montreal write Dept. 109. - = "VE scored again! Aqua Velva is the new product—a scientific preparation for use after shaving. For free trial bottle, — i ¢ cap was: BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Making the Most of Your Milling Machine (Continued from page 95) from one hole to another. It is seldom advisable to depend upon the micrometer dials on the machine, although these may give a close approximation to the sizes. The majority of operators are more or less familiar with the button method of locat- ing holes that are to be carefully bored in a given relation to each other. In applying this method to the milling | machine, if we assume that the work has been carefully laid out and the button applied, the piece can be set up on the machine as indicated at A in Fig. 5. After this has been done and the piece clamped against an angle plate or on the table, according to requirements, we must pro- vide a hardened and ground plug B, lapped accurately to the exact size of the button used. This plug is inserted in the spindle as shown, and a sliding sleeve, C, is placed over it. This sleeve must be a very nice fit, without any shake whatever. In use, the table must be adjusted until the sleeve can be slipped freely from the plug over the button, at which time it is evident that button and plug are in aline- ment. Back-lash in feed screws must be taken out when alining button with sleeve, and if the former is a trifle higher than the plug, lower the knee below the required | point and then bring it up again, to take up all lost motion in the screw. In making longitudinal adjustments, the same idea must be followed. FTER the spindle is set, the button and plug are removed and a drill is inserted in the spindle, to be followed by the usual boring bar or reamer. It is always best to generate the hole accu- rately by means of a boring tool, as the reamer may be slightly off center and thus cause slight errors in the position of the hole. A careful operator can obtain very good results by this method, although some prefer to mount an indicator in the spindle and obtain the setting by adjust- ing the table until the indicator reads the same at four points 90 degrees apart around the button. It is rather difficult to see the indicator pointer in some posi- tions, but this difficulty can be overcome by using a small mirror and an electric light. location produces more accurate results than the plug and sleeve arrangement. For short jobs, don’t worry too much about your feed and speed, because the | cutting time is less important than the | setting up. Use a conservative feed and speed and spend your time to the best ad- vantage by studying out a simple and ac- As a general thing, this method of | curate method of setting the work in posi- | | tion and holding it there when you have | placed it properly. Ordinarily use slow speeds and comparatively coarse feeds for roughing cuts, with higher speeds and | | finer feeds for finishing. Chatter often can be avoided by changing the relation of feed and speed. Cast iron usuaily is cut dry. Bronze | and aluminum can be cut either dry or | with a lubricant. Tool steel or alloy steel | and steel castings are best cut with a | lubricant. Plain lard oil is very good, but (Continued on page 97) | ownership. | tion. Elements of RadioCom. munication E. W. Stone For the man who wishes to under. | stand the general theory of radio | communication. A complete, up-to. | date discussion presented in simple | terms, of every phase of radio-tele. | graphy and radio telephony. Price, postpaid, $2.50 Henley’s 222 Radio Cir. cuit Designs An entirely new and thoroughly practical book on radiocircuit designs, Contains the largest collection of radio circuits and hook-ups ever published. Price, postpaid, $1.00 The A B C of Vacuum Tubes Used in Radio Reception E. H. Lewis RADIO} Written particularly for the person who ‘‘knows nothing about radio” | but who would like to gain an under- standing of the elementary principles of operation of vacuum tubes and Variouscircuits in which they are used, Price, postpaid, $1.00 How to Build Your Radio Receiver Edited by K. Banning and L. M. Cockaday This book tells just exactly how to build your own receiving set, how to install it and how to operate it. Full detailed instructions are given for building seven different receivers, the receiving radius of which ranges from fifteen to over three thousand miles, Price, postpaid, $1.50 Cram’s International Radio Atlas Double page Radio maps of the United States, Canada, the World. Broadcasting stations of the world with call signals, wave-lengths and General Radio informa- Size 12” x 15”, Price, Fifty Cents Cram’s Radio Map A comprehensive Radio Map of the | United States and Canada, showing } government, commercial and private stations: completely indexed. Size 28” x 34”. Price, Thirty-five Cents Popular Science Monthly 250 Fourth Avenue, New York, N. Y. | | | | n tl : ee ae ae a he. |

Page 97

= Ome under. | radio | Up-to- simple 10-tele. ) Cir. oughly esigns, ion of ever 1um adio person radio” under- nciples s and e used, ) four ie M. 10W to 10W to . Full -n for rs, the s from miles,

onal of the Vorld. world Ss and ‘orma- ip of the owing rivate Size

ithly

ae Adjustable Jig for Drilling Holes in Round Bars | 4 CHEAP and pusnine | yet accurate | ;gfor drilling holes in round stock can | he made as illus- ‘trated. A square ‘block, | provided | with a V-groove, ‘js fastened to the ‘upright by means * ‘of a T-slot. The ‘upright is grooved ‘to allow the bush- ‘ing bracket to be ‘adjusted up Or Sipe | down. A 14- or 3<-in. hole is drilled in the end of the block to receive a bent rod, which acts as a gage. The gage is held in any desired position by a setscrew.

‘Safety Hand!te for Jointer Holds Thin Stock Firmly HEN planing thin strips of wood on the jointer, the danger of accident may be reduced by providing a handle or holder made as shown. It is placed ‘over the strip to be planed, the end of which is caught against the cleat. The latter may project ¥ or 4 in. below the lower surface of the holder, as desired. Two sharp pointed nails which project slightly through the holder, prevent ' the strip from | moving sideways | Holds thin stock firmly under pressure.

| Making the Most of Your Mi-ling Machine (Continued from page 96) for very hard materials white lead and oil 'givea smoother cutting action and this composition also has the property of | clinging close to the cutter and adhering | to it more than does plain oil. | Inhigh production milling, a compound usually termed “‘soda-water’’ often is used, but for short-job work machines are seldom provided with pump and tank needed for this sort of lubrication. It should be remembered that the lubricant serves two purposes, reducing friction and cooling the cutter. For short jobs we need it mostly for reducing the friction and making the cutting action easier. Many operators dislike using lubricant on a milling machine because the oil and chips cling to both cutter and work and make it more difficult to see the action of the cutter. When the lubricant is used only in small quantities, it has no force and being only a small stream it does not | Carry away the chips. Likewise the chips and oil muss up the machine. This is a lazy man’s point of view and should not be tolerated by a good operator, for it is Certainly much cheaper to spend a few minutes in cleaning up the machine than itis to regrind a cutter.

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY £ t }

QUARTER-INCH PORTABLE ELECTRIC DRI “With the Pistol Grip.and Trigger $36, Bench Drili- ing Stand. The drill can be in- serted or de tached quickly by means of handle clamp. $12, In Canada $16

Grinding Outfit. — Consists of stand which can be fast- ened to bench top, arbor with clamp washers and “~ nut, and grinding wheel. $3—1n Canada $4 Nine Tube Radio Receiver In Three Evenings One radio fan says his Black & Decker Electric Drill enabled him to build a ‘‘Set’’ consisting of Three Stages of Radio Frequency, Two Stages of Audio, and a Three Tube Push-Pull Power Amplifier, in three evenings at ome. This included making the panel and the process he devised will interest other fans; this is how he did it: mi Mounted all instruments on the base in the best positions to insure short grid and plate leads. (Longest grid or plate lead on the set is 2 inches.) Laid out panel on a sheet of wrapping paper cut to the exact size of the panel. Panel instruments were located to avoid interference with base instruments—to insure shortest possible connections—for convenience in operating and symmetrical appearance. : , Under side of this paper pattern was then coated with ordinary library paste and pasted to front of panel. With a brad awl centers were punched thru paper and a th inch lead hole drilled thru every center punch mark. These were followed up with various size drill bits to accommodate the various mountings. (Sizes of holes having been indicated on the paper pattern.) By using the electric drill and stand all these holes can be drilled before the paste has dried. This is important because the paste will not hold on the panel after it is dry. When paste is dry, paper pattern is merely lifted off and the panel wiped clean with a wet cloth. This Panel, Angle Brackets for Binding Post Panel and Binding Post Panel itself required the drilling of 60 holes of various sizes. The Drill and Stand enabled this man to drill so accurately that every instrument was mounted easily without additional fitting, resulting in a 100% panel job. Photograph of completed panel will be mailed on request, 1S3 Every radio builder should have one of these drills and stands.

Orders and inquiries may be mailed to We BLACK & DECKER MFG.CO. 700 Pennsylvania Avenue, . Towson, Maryland In Canada

i BLACK & DECKER }

Page 98

T’S economical to a ‘‘Red Devil.”’ The hand honed steel cutting wheel cuts ciean and sharp, with the slightest pressure—stands the test of hard use. The handle is shaped to fit the fingers without tiring. More ‘‘Red Devil’’ Glass Cutters used than all others—try one and see why. MM Ask your hardware dealer for “Red Devil’ Glass Cutter No. 024, 20c. each. If not in stock, send dealer’s name. FREE: Smith & Hemenway Co., Inc. Mfrs. of **Red Devil" Tools 264 Broadway, New York, N. Y. MECHANIC’S TOOL BOOKLET “Red Devil’ Pliers, Auger Bits, Snips, Hack Saw Frames and Blades, Screw Drivers, Chain Drills, Cold Chisels and Punches, Linemen’s and Eleciricians’ Tools, etc. At last! a 100% Woodworker Only $225.0 complete with motor 8 ineh Circular rip saw 8 inch Circular cross cut saw 11 inch Band saw 4 inch Jointer Shaper 10 inch sander lathe-14 inch swing ARKS Cabinet Shop Special is as complete a small shop equipment as you can buy! Everything in one com- pact unit with motor! Just the machine for your home shop —for the cabinet maker—novelty and toy-maker—special furniture builder— for the farmer who makes his own crates, bee-hives, etc. No end to its usefulness! Complete, or without motor and at- tachments to suit your needs. Write for circular The Parks Ball Bearing Machine Company 1547 Knowlton St., Cincinnati, O. Canadian Factory: 200 Notre Dame East, Montreal, Can. PAR seat yt Sobers |! ‘COODWORKING Send for this valuable booklet. Learn how you can cut down your coal-bills 20 to-50%—get more heat from less coal—fire the furnace fewer times— decrease the amount of ashes—reduce smoke. All this by quickly attaching a simple inexpensive device to the feed door of your furnace. More than 15,000 homes know the comfort and fuel savings made possible by The CROWN Fuel Saver HEAT FROM PERFECT COMBUSTION . } if : \ any Pry ae pnb BD iy 3 .. MOT OXYGEN... ~ SMOKE /- UNBURNED GASES GUARANTEED to make at least a 20% coal saving or your money back i uarantee takes all guess work out of buying the CROWN. You install it and it does its work or we refund every penny you paid Write today for FREE booklet and fnll details of this amazing heat-producer and coal saver. Cc. F. S. Co., 19 N, 10th St., Richmond, Ind. DISTRIBUTORS WANTED—High-grade men who seek a steady income. Write or wire. This BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY “Red Devil” Glass Cutters The Glaziers’ Standard do the little home glazing jobs yourself with | Large Cap Prevents Speed | FLANGES ON CAP eer ‘ Lathe | from Splashing Oil AYY one who has been splashed with oil thrown by the spindle of a wood. | turning lathe will appreciate the methoq of protection indicated in the accompany. ing illustration. The bearing cap is mage about 1 in. longer than the lower half of the bearing. This allows 1% in. to pro- 7 TIN GIL ‘ oS GUARD ject on each side ia _, . the cap being cut back to allow the hubstorevolye under it. If the expense of making new caps js to be avoided, a piece of tin fastened on each side of the cap will serve the purpose.—F. N. (¢, £2 Two types of oil guard Adjustable Drill Jig HE simple drill jig illustrated is a useful fixture because it can be ad- | work and shafts, as well as pin holes in | studs and similar work. A rotating head is pivoted to a block | ROTATING CLAMPING BLOCK provided in one end of the head to take drill bushings of various sizes. has a great deal of surface filing to do can be made by bending two pieces of 14-in. plate to form a file holder as shown. The plates are held apart by 4 separator and two wooden handles are riveted to them. The central clamping bolt is screwed up tight to hold the file between the jaws. that can be clamped along with the work | in the drill-press vise. A bushing hole is eres FASTENING BOLT \S~ HARDENED DRILL BUSHING VISE The jig is adjusted by sliding the clamping block and rotating the head In use, the jig is clamped as shown and the head with the proper bushing is manipulated until it is directly over the proper spot, the adjustment being ob- tained by sliding the jig block along the vise jaw. vise screw then are tightened to clamp the jig in place.—G. A. L. The fastening bolt and the Holder for Surface Filing WOOD TOOL for the SEPARATOR mechanic who "i TO ANNEAL high speed steel, heat slowly to a dark red; cover with lime or ashes. and allow to remain until cold. then be worked as soft steel. It can | | | justed to suit the location of various holes | that have to be drilled in straight flat Ri great } trated | mits,

Page 99

en Lathe ed with 2 Wood. | method mM pany. 1S Made half of . This to pro- h side, ng cut OW the Volve ense of Caps js ded, a astened of the ve the N. C, d is a| be ad- | 'S holes | ht flat oles in | | block | 2 work | 5 are ping e file owly shes, t can BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY = Lift Attached to Lathe for Handling Heavy Chucks | EMOVING a heavy chuck from a R large lathe is a task that is lightened reatly by the use of the special lift illus- 1 Q 5 | sated. When the design of the lathe per- mits, ROPE TACKLE and braced from the lathe bed. The upright is a bent bar iron with a hooked end. This supports either a short turnbuckle or, if the stand is high enough, a Allows one man to small rope tackle. handle large chuck A hole is drilled and tapped in the chuck to receive an eye-bolt. When removed from the rest, the chuck may be swung to one side and allowed to hang ready for use when wanted. This allows one man to handle a heavy chuck. Shaper Tool for Keyways \ HEN no reg- ular key- cutting machine is available, keyways may be cut quickly in the shaper with the tool illustrated. |The holder, forged | toshape as shown, | hasa 14-in. reamed | hole that takes the tool bar. In the alien ieee te lend of the bar is a small pulley hub toolbit, held with a setscrew. If the holder is pack hardened, it will give and wear longer. Bars can be made of different lengths and sizes. For work on short bushings, gears and small pulleys, this tool-holder isa real time-saver. Lock Pins Frevent Turning of Countersunk Screws HE countersunk screw is one fastener for which ordinarily no method of locking is provided. In some cases, it is true, the head is chiseled, riveted, or prick punched, but these methods cannot RETAINING PIN RETAINING PIN pRiVEN DOWN A small bent steel rod is driven into diag- onal holes to lock the screw-head slot de depended upon always to hold against vibration and other strains. In one shop countersunk screws are locked by the simple but effective method illustrated. Two small holes are drilled diagonally at the ends of the screw slot and into these is driven a steel rod of the | Same diameter, which straightens out into | the screw slot and holds the head. ee this may be fastened directly to the | back of the bed, or | _TURNBUCKLEOR jt may be carried | _down to the floor | | | | a | ¥— ae 2 FROZNPURE See Quality « Service GMC Is The Big Mileage Truck There is big mileage in every General Motors Truck. Big mileage free from anything but casual service atten- tion. Overstrength in every part. Long miles fully loaded up steep grades through bad going —bad roads or good look the same to the now famous GMC Two Range Transmission. It enables a GMC and its load to go anywhere the wheels can get traction. Big mileage on gasoline and oil. The Two-Range Trans- mission furnishes both speed and pulling power with an engine of economical size. Big mileage per dollar of cost. GMC Trucks are closely priced—cost less than other trucks of competitive quality and comparative capacity. Ask why! Big mileage without dead time in repair shops. Ask for a catalog and see why! GENERAL MOTORS TRUCK COMPANY Division of General Motors Corporation PONTIAC, MICHIGAN “General Motors Truck Co. - Pontiac, Michigan Department 47 _ Gentlemen: Please send me further information. I am interested in a (truck) (dealership). Name Address

Page 100

£ fe s , v Snap-on ’ Snap-on Socket Wrenches H Ee __ janet t" |qpeae ; Jaana

Look for this cabinet at your dealer’s If your dealer hasthis Snap- on cabinet, he is ready to give you real wrench ser- vice for your car. He can supply you in a jiffy with a wrench for one job, or a Kit, like the one below, specially selected for your car. Write us if he hasn’t the cabinet. We’ll serve you and him, too.

» SNap-on INTERCHANGEABLE Socket Wrenches MOTOR TOOL SPECIALTY 14 E. Jackson Blvd., CHICAGO Gentlemen: Please send me full particulars about Snap-on Kit DoE G< 9 ee erie car. (If interested in Master Mechanic’s Kit, check here ) ieee eee eee eee ee eee eee ee ee 2 2 rs HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Easily Built Aquarium and Stand By William J. Edmonds, Jr. SMALL aqua- rium lends a touch of color and interest to a sun porch, living-room or dining-room that well repays the cost and labor of building one. Not only has it a decora- tive quality that is difficult to duplicate by other means, but it provides a fascinat- ing study for the children. Its revelations become more interesting the longer it is left unagitated, and for that reason the aquarium illustrated is of such a size that it can remain undisturbed for some time. To construct it, first obtain about 18 ft. of 34 by 34 by 1¢ in. angle iron for the frame (Fig. 1). This may be bought at any hardware shop or dealer handling iron and steel; it should cost about 50 cents. The ends of the horizontal rails, A, should be beveled at 45 degrees with a hacksaw and finished with a file. The pieces then are drilled for 3/16-in. rivets. These holes are not countersunk. The vertical or corner pieces, B, next are cut and drilled, as indicated, and the holes are countersunk on the inside for the rivets. The holes in these pieces should be marked according to the holes already drilled in the horizontal pieces, A. It also may be well to mark each piece so that the pieces will be ture well and le stand 3 or 4 hours jy. fore using. When the glass has been a. mented in place, the aquarium js left t, dry for 3 or 4 days before water is places in it, and 3 or 4 changes of water are then made, allowing 1 or 2 hours betwee: changes before any stock is put in. _ The frame is finished in Any color enamel desired. 7 ced : iw, y | 4X4 Xe" ANGLE Z a —3 DRILL FOR 3 Rivets 20"- 4 REQUIRED (A)

+—— 14") saan * asses x. ‘ 4x94 xY6 ANGLE? [ ¥ “as eae a

DRILL FOR 3c" RIVET 4 REQUIRED (A) b+—— 14%» ae — Ya X34" Ve" ANGLE hati—~ GLASS

CEMENT

DRILL FOR ie RIVET 4 RFOUIRED (p) Fig. 1. Details of the aquarium framework and method of cementing the glass in place

assembled in the same order This aquarium, of course,

as they have been laid out. When the frame is to- gether, it is taken to a glazier and fitted at the sides, ends, and bottom with !4-in. plate or double thick window-glass. The bottom glass should be a good fit, but the sides and ends should be slightly shorter to allow the cement to be pressed into the joints to form a dovetail, as shown in Fig. 1. The space marked C, which is found between the glass and the horizontal

can be placed on any cor- venient table or stand, but it looks particularly well when set upon a stand made specially for it as illustrated. This stand is very simple in construction. The top, 4, Fig. 2, is made of two or more pieces of stock dressed ¥% or 34 in. thick and glued together. It is advisable | for the amateur woodworker to use at least 4 dowels in| each joint. | The upper rails, B, and

pieces, should be filled with cement, for if these spaces on its

AQUARIUM TABLE ie a TABLE TOP j 74 OR ¥4 THICK = | i

l-—— 23" ——-»| i 9" 1 C205 hp

i: Seeman ( 2. iC SS) es { ' Ya SQUARE jAdkcomaeel b @

Wy Bf 1Y%2" SQUARE a

C 15%" SARE - { : if =] Va LEGS (D) L— })* —} Fig. 2. The stand with dimensioned de- tails of the top, rails, legs, and stretchers were allowed to remain open, the pressure of the water might spring the glass and cause a leak at the corner joints. The cement is made as follows: Lith- arge, fine dry white sand, and plaster of Paris, each 3 parts, and fine pulverized rosin, 1 part, are mixed together thor- oughly with boiled linseed oil, to which a little drier has been added. Beat the mix- The completed aquarium wooden the lower rails or braces, (, are of the dimensions given. These pieces have tenons cut on the ends to fit mor- tises in the legs. The legs, D, are dressed to 114 in. square and have mortises cut asshown. After the pieces are cut and | have been fitted together, the joints are made with a good grade of glue and the | top is fastened in place by means of wood | screws passing through the upper rails | into the top, holes first being bored to) allow the heads to sink into the rails. | Table-top fasteners, which can be ob-| tained at a hardware store, or wooden | blocks, may be used for holding the top | if the builder prefers. After the stand is assembled, it 1s cleaned with sandpaper or, if made 0 hard wood, scraped and sandpapered, and then given a coat of stain and filled. It is then shellacked and waxed or varnished. Stock for the aquarium may be pur chased from any dealer in aquarium sup- plies, or may be selected from slow running streams or ponds. stand

An article by Mr. Edmonds on build- ing a mission rocker is scheduled for | early publication. ———

Page 101

Saisie 1d id let it hours be. been (e is left tg 1S Placed Water ar S bet weer in, NY color

GLE Z Ye Rivets! ‘D (A)

“RIVET “D (B) 1ework 1 place of course, any con- tand, but arly well and made lustrated, simple in e top, A, of two or ek dressed and glued advisable | yod worker dowels in

on build- Juled for | — : , ps = HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

plueprints for Beginners to Be New Workshop Feature «| CAN’T build any furniture,” recently remarked a friend to the Home Workshop Editor of POPULAR SCIENCE \onTHLY. “I haven’t the time nor the tools nor the knowledge. Manual training qasn’t taught in the school I attended, and I never learned to do anything but ordinary little woodworking jobs around the house. You show me something that looks really well and yet can be made without mortises and tenons and dovetails and dowels and a whole lot of time - consum- ing cabinet ——— work!’’ oof Lp It was a diffi- 4 > cult challenge, yet one long foreseen. Indeed, the Editor had his answer ready. It was in the form of a drawing for the first of a new series of blueprints for beginners—a design for a radio cabinet calling only for simple butt joints and workmanship of the most ele- mentary kind. Yet this cabinet has a finely figured, veneered case as well as the overlay type of ornamentation and two- tone finish now so popular. The design and working details will appear next month.

<4 AW an f Wie

(is g ited

Complete List of Blueprints | oe 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 250 Fourth Avenue, New York. GENTLEMEN: Sendmetheblueprint, orblueprints, I have underlined below, for which err es cents: No. Title Price OS ra at Ch 25c A. WOMOKING CADINCT.. «....0 5 s0cieeicess 25c 3. Book Trough End Table......... 25c AE SS aN On ST rae 25c 6. Two-Stage Radio Receiving Set... 25c S SNAVitig Capimet. ....... 00. 00 606s 25c 9. Arbor with Gate and Seats... .....25c MO COSC SMA 5. 6c 5 o.6. 0.6.2 s+ 0 00.0 6% 25c 11. Bench and Tilt-Top Table........ 25c 12. Electric Washing Machine... .....25c DD RPA MNMIE DORE alerts ives oe ciaiaers!e 25c 14. Toy Train, Horse, and House..... 25c 15. Home Workshop Bench.......... 25c 16. Inlaid Radio Cabinet............ 25c 17. Cedar and Mahogany Chest...... 25¢ 18. Telephone Table and Stool....... 25¢ 19. Grandfather’s Clock............. 25c a0: Klat Top Deshe.. ....<.06ss00 00000 25c 21. Colonial Writing Desk........... 25c 22. Girl’s Cabinet and Desk......... 25c 23. Pergola Garage............e000- 25¢ MS Gateleg ADO. 65 <:0:00.0:056:s 0.640505 25c 25. Sailing Outfit for Canoe......... 25¢c 26. Baby’s Crib and Play Pen........ 25c 27. Kitchen Cabinet Work Table..... 25c 28. Pullman Play Table............. 25c 29. Toy Tea Cart, Garage, etc....... 25c 30. Tool Cabinet, Bench Hook, etc.. .25c 31. Priscilla Sewing Cabinets........ 25¢ 32. Chinese Game Table............ 25c 33. Pullman Dining Alcove.......... 25c 34. Trellises for House and Garden... 25c sme... ey ee ee ey

“When Time’s Forgotten” FELLOW is apt to forget the time when he’s getting alot of fun out of good tools. For instance, a Simonds Saw sings its way across a board with so littleeffort. Thereare many reasons why, mostly due to Simonds over ninety years’ experience making tem- pered steel cutting edges. Ask your dealer about SIMONDS Hand Saws, Hack Saws, Files, Circular and Cross-Cut Saws © SIMONDS SAW AND STEEL CO. *The Saw Makers” Established 1832 Fitchburg, Mass. Branch Offices in Principal Cities

mee d IVES S “ST,

Page 102

U.S. Government Needs Men! ONDERFUL opportunities in Service. Thousands of appointments made yearly. Generous salaries, liberal vacations (as much as 30 days with pay in some branches of the service), pen- sions, sick leave benefits, short hours (from 9 to 4.30 in Washington), congenial working conditions. Civil Men and women are needed right along as Income Tax Auditors, Bookkeepers, Post Office Clerks and Carriers, Customs Cashiers, Railway Postal Clerks, Deputy Collectors, Postmasters, Gaugers, Stenog- raphers, ete. Positions are open in Washington and in every city of the country as well as in Alaska, Porto Rico, Hawaii, and the Philippines. Over 29,000 appointments were made in one year in the Post Office Department alone! “Pull” and influence unnecessary. Com- mon school education is suflicient as groundwork for most positions. Examinations are easy to pass if you have proper coaching. tight at home in spare time through the International Correspondence Schools you can learn to not only pass your examination, but to pass with a high mark. The higher your rating the more certain you are of an appointment. Thousands of men and women now employed by Uncle Sam prepared for their positions through I. C. S. training. Mail coupon to-day for 48-page FREE CIVIL SERVICE BOOKLET OX 7614-y, Scranton, Penna. Without cost or obligation, please send me a copy of your 48-page CIVIL SERVICE BOOKLET, which tells how can with the | | 3 | u: 8. | | secure a Government, meee ce cs es ee es ee ee oe INTEL NATIONAL CORRESPONDENCE SCHOOLS position | Name Street Address.... City... 200°, PROFIT ormore. 9 outof 10 women buy Pro- duces keen edge quickly Sells for 50c. PREMIER MFG. CO. Dept. © Detroit, Mich’ NOW ONLY $35 puts this HB One Day Battery Charging outfit in your shop, complete with bench, bus-bars, connectors, cables, etc. Easy terms on balance. The lowest priced complete outfit on the market. Start now to make $1500 to $3000 yearly charging batteries. Send for free Bulletin 94. HOBART BROS. CO. x P 9, Troy, AGENTS Make $10 to $20 daily selling Premier Knife and Scissors Sharpeners. ©. Sy hio HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE | a cheese-cloth pad. How to Keep Your Automobile Polished (Continued from page 79) is to use a sponge, which alternately is dipped and squeezed over the surface. It is permissible to use the force of the hose | under the mudguards. Clean chamois should be used imme- diately to dry the varnish. Good polish of various grades is obtain- able ready prepared. A polish containing grated beeswax or cedar oil is desirable, and paste wax polish, which comes in small tins, is excellent. The writer has a preference for a simple paraffin polish, which is made by dissolving shavings of household paraffin for several days in the smallest possible quantity of clear tur- pentine. By the use of these wax or paraffin polishes, the surface of the varnish is covered by a glasslike coating. This will respond with a bright luster when rubbed with the cheesecloth, and it will shed rain. OR winter use, when the owner is not concerned as much about the gloss as he is about preserving the finish, a protective polish made of two parts of boiled linseed oil and one part of turpen- tine will be found even more protective than wax polish. If desired, varnish can be added to the turpentine, using one part in five. A polish so made is applied with Monthly applications | of these oil polishes will result in excellent preservation of the varnish throughout | the winter. A clean turpentined cloth will remove the linseed-oil polish before re- turning to the more brilliant wax polish in the spring. For top preservation, the use of raw linseed oil and turpentine, two parts to one, is excellent. kerosene on imitation leather top or up- holstering, as it dissolves the coating. Use Castile soap and clear water to wash the top as well as the body. The upholstery also can be washed, if of leather or imitation leather, and can be Never use gasoline or | polished with a cloth slightly dampened | with the paraffin polish. Washing the car in sunlight or washing | the engine hood while it is hot should be avoided, because the varnish is almost certain to become spotted. To summarize the care of the finish as practised so successfully by Jackson: 1. Avoid direct sunshine if possible, by parking in the shade, and protect your car from rain and snow by running it into the garage or by application of oil and wax polishes to shed the water. 2. Before using a cloth on varnish, re- move grit and mud with a duster or by flushing off with water. 3. Use a good grade of wax polish over the varnish, and apply it only after the removal of all grit and dirt. 4. Use only cleaning materials that are free of grit and keep al! cloths and ma- terials in a separate closet where they will remain clean. WHEN painting a floor in a room that is much used, I usually paint a few pieces of burlap, old oilcloth or linoleum with | the same color and use it to cover spots that get particularly hard wear.—O.M.A. i | MONTHLY For that Jolly Beach Party Pack your week-end bag, Say goodbye to the hot, noisy city and set out for a day or two of real fun and healthy sport at the lake or sea. And don’tforget to takealong your pock- et orchestra so there’ll be plenty of good music for those who want to dance. If you want to be the hit of the party, be ready with a Hohner Harmonica— ° The World’s Best There’s nothing like good music for hap. piness and there’s nothing like a Hohner for good music. Hohner Harmonicas are true in tone, accurate in pitch and perfect in work- manship. Get a Hohner Harmonica today and play it tonight. 50¢ up at all dealers, Ask for the Free Instruction Book. If your dealer is out of copies, write M. Hohner, Inc, | Dept. 162 New York City. A OHNER ARMONICAS a Th2 Saw That Saves = No need to buy a “‘hizh Cie. J priced”’ bench machine. The “Utility’’ will saw, sand, groove, bore, dado and mi- ter for you at very low cost. Boice-Crane “UTILITY” Saw Built for Heavy Service Saws 214" stock. Dadoes 1” wide by 114’ deep. Table elevates with micrometer exactness for grooving. Sold with or without base. Driv- en with 1/3 to % h. p. motor. Soli on Money-Back Guarantee Write for descriptive folder on Bench Saws, Band Saws 1S} and Jointers. . B. & J. E. BOICE, Dept. P. S.9, Toledo, O. ie! | 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; Illum- 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. Price $3.00, postpaid. POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York, N. Y- 500 pp. Illus., ——~ D> 4 ot

Page 103

ye to the for hap- ohner for Te true in in work. ca today lealers, If your ner, Inc,, istry ts Uses ic Acid; lorganic ils and I]lumi- Distilla- idustry; Wood; ng Oils; ycerine; s, Gum- Sugar, Gluten: \ pplica- yl ysives ostpaid. THLY c, N. Y. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY ee e Keeping Photographic Developer | at Correct Working Temperature | 4 MATEUR photographers who have AA their darkroom in the cellar often and the problem of keeping their de- yeloper in the neighborhood ot 70 degrees , dificult one. Cellar temperatures range from 50 to 55 degrees in winter weather to 60 to 65 degrees in the summer. In my own case the device illustrated solved this problem satis- factorily. It consists of a tin tank holding _ about 2 gals. of water set in an ig posing — asbestos - lined box. The top is two thicknesses of tin with asbestos inter- lining. The opening for the tray is just large enough to allow it to settle down in contact with the water. Openings also are provided for a ther- mometer and an electric immersion heater. _—C. E. WEIBEZAHL, Syracuse, N. Y. | How to Install Automatic Light | in a Clothes Closet pees clothes closets usually can be equipped with electric light at small cost. The best installation includes an automatic door switch, which turns on the light when the door is opened and turns it of when the door is closed. If the closet is on the second floor of a two-story house, the wires usually may be run in the attic. If on the first floor, the easiest way often is to bring the wires from underneath the floor. The material required is a sufficient amount of No. 14 rubber-covered wire to run from the lighting wires already installed, a few TO MAIN porcelain knobs or anid WIRES cleats to hold the 2 wire from the wooden beams, about 10 tt. of 7/32- actin In, circular loom DOOR SWITCH to incase the wires where they come through plas- ter and where they tun on the surface Diagram showing ar- of the wall down rangement of wiring to the switch, a keyless receptacle for concealed work, with either an automatic door switch or a door-mounted hand switch. A small piece of solder and tape also are necessary. To conform to the requirements of the Board of Fire Underwriters, it is necessary that wherever the wires are tapped on to the main house line, the joints must be soldered and wrapped with rubber and iiction tape. The wires must be sup- ported from the framework or beams on porcelain knobs or cleats, and circular ‘om must be used, as indicated above. If the wires are run under the house, BX cable or conduit must be used unless the distance from the floor to the ground ‘89 it. or more, in which case open knob and tube work and rubber-covered wire | will do.—C, P. ANDREW, Charlotte, N. C. 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

Page 104

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY A Valuable 68-Page Reference Book on Radio—a Market Place for the Best in Sets and Parts We want you to have a copy of Ward’s new Radio Catalogue.: You will find it to be an encyclopedia of information on Radio, the livest topic of the day. It con- tains a new Radio map—diagrams of the best hook-ups—descriptions of complete sets, and standard parts for building sets. Headquarters for Radio Montgomery Ward offers you all types ESTABLISHED 1872 Montgomery Chicago Kansas City St. Paul of Radio Equipment at a saving. We sell direct to you only merchandise of high- est quality. Everything you buy from us, carries our 52-year-old guarantee—‘‘ Your money back if you are not satisfied.” Enjoy the Long Winter Evenings Every form of entertainment can be brought into your home by Radio. Keep in touch with the world—Sports—Elec- tion Returns—Dance Music—Speeches —Sermons—Current Events—you can enjoy them all by Radio. Write today for your copy of this com- plete Radio Catalogue. Address our house nearest you: Dept. 5-R. Ward &Co The Oldest Mail Order House is Today the Most Progressive Portland, Ore. Oakland, Cal. Ft. Worth Innovations that set NEW Standards of Condenser Efficiency HE efforts constantly directed to keep U. S. Tool Condensers a leader have resulted in these remarkable new features. One Piece Stator, Hexagon Shaft— e'iminating fanning of rotor blades, Three Mounting Lugs and Pigtail Connection. Guaranteed 3%, plus or minus, from indicated capacity. Ask your dealer to show you these new types: Nos. 3 and 4, with celeron end plates. Nos. 5 and 6, with low loss metal end plates. 100% GUARANTEED Write for Literature VU. S. TOOL CO., Inc. 127 Mechanic St., Newark, N. J. Mfrs. of special tools, dies, j'gs, automatic machiner a and sub presses. ) 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 knite blade can never fold or turn and injure you. Beautifully made, an unusually handy tool for a thousand uses. Handles blued to prevent rust. Model No 1t for $1.80, and No. 12 for $2.25. Send money order or vour check and we will ship post prepaid at once. Each tool guaranteed. Your money retunded 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. 5-9 Santa Ana, California How to Make a General Utility Scraper for Woodwork ~ GOOD scraper is an indispensg}), tool in the home workshop, |; ; useful for smoothing hardwood floors pte paratory to sanding and finishing, eye, though a_ weighted, wheel-mounte, scraper or motor-driven sanding machin, has been used first. It is of value jn a facing and smoothing all kinds of po, woodwork, for cleaning old floors that are to be refinished, for removing rust and scale from metal, and for taking off old paint, varnish, or putty from wooden gy. faces. When a commercial scraper holder js not available, a substitute may be mace as shown. Use a piece of seasoned beech, maple, or other hard wood about 11; jn, thick and 15 in. long for the handle, p. Cut the end at an angle of 45 degrees to take the tool seat, C, which should be of hard wood 3 in. long, measured with the The scraper and method of sharpening the edge grain, 414 in. wide, and at least °, in, thick. . Bevel the lower edge and round the upper edge. With a rabbet plane or a sharp chisel, cut a recess across the face of this piece, slightly less in depth than the thickness of the scraper blade, A. Attach it to the handle with flathead screws. The clamp, D, is 34 by 3 by 4), in. hard wood cut with the grain running up and down, at right angles to that of C. A bolt with thumb-nut hold this against the tool seat, clamping the blade. The blade may be a cabinet scraper, a piece of steel cut from an old saw blade, or similar hard, well-tempered steel. Two opposite edges are filed or ground to an angle of about 45 degrees and, for fine work, rubbed on an oilstone to a chisel- like sharpness. Then clamp the blade in a vise and draw across it from end to end a burnisher, nail-set, or other hard tem- pered tool. Use considerable pressure end gradually turn the edge over. A little ex- perimenting will show the amount of burr that will take off a fine, clean shaviog from a wooden surface. If the burr 1s turned over tco far by accident, it can be | raised by running along it the point of a burnisher or penknife. To use the scraper, apply pressure | against D with one hand and with the other hand draw the handle toward you, with long, regular strokes. Keep ” handle parallel with the surface of the work. : When one edge of the cutter becomes dull, the blade may be reversed. 3urnish the edge frequently and resharpen It at intervals, as necessary.—HOWARD | Goon, Waterville, Ohio. —— | | _fkitle’d) wa aie \\

Page 105

| Utility ork OP. It jg floors pre, ing, even -Mounted > Machine Ue in sup. S of ney S that are Tust and 12 Off old oden sur- holder is be Mace ed beech, it 11) in, andle, B. legrees to uld be of with the t 34 in, | und the ne ora the face th than ade, A, flathead ) by 415 running at of C. against raper, a , blade, 1. Two | 1 to an| for fine chisel- lade in to end d tem- ire end ttle ex- of burr havizg burr is can be int of ressure th the d you, p the of the comes urnish . it at p E. ee outside Service Door Improves | gq “California Cooler’’ By A. May Holaday ‘17 IS difficult to estimate the number || of steps saved every week by the use of a small service door set into the “egoler,” as the ventilated cupboard so | common in California is called, or, indeed, | any kitchen cupboard that is built against | @n outside wall. Ata convenient height for the milkman, | an opening is cut through the wall and | qgsed all around like a window. A small ot — __— eee | ELEVATION (OUTSIDE) Milk bottles placed on doorsill are taken in by reaching through cooler from inside | 12 by 12 in. door is hinged to open inward between two shelves of the cupboard, and is fitted with a cupboard catch. By reaching through the inside door ‘from the kitchen, one can place empty bottles through the outside door-opening ‘onto the flat sill, where the milkman re- places them with full bottles. Thus, instead of taking many steps across kitchen and back porch, the house- wife merely opens her cupboard door, and draws the full bottles of milk inside to the cool cupboard. Small Drill Press Quickly Made for Emergency Use PY AN emergency, when several hun- dred holes have to be drilled in sheet- brass parts, a drill press was quickly made from material on hand in my home work- shop. A 114-in. plank, 8 in. wide and 2 ft. long, was pivoted by means of a bolt and OR ELEVATING K CAM _— y : “Tt WEIGHT Hand drill clamped to pivoted plank pro- vides means for doing light drilling speedily yooden spacers to a shorter plank and the |‘atter was gripped in the bench vise. A land drill then was fastened to the free id of the longer plank with a C-clamp. | An arm of thin wood pivoted as indicated 0 the long plank, served to elevate the aril, and a weight provided the necessary *tessure for drilling. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY \ NS MICADONS —condensers of fixed and permanent capacity You will have condensers that maintain their fixed capac- ity if you buy Micadons. These accurate Dubilier Micadons are found in over ninety per cent of the sets made by amateurs and manu- facturers throughout the country—The experts specify Micadons. The name Dubilier on a condenser has the same meaning as the name Sterling on silverware—quality. There is a Micadon for every circuit—different types are made for different requirements. For free booklet showing method of soldering Micadons in radio circuits, address, 47 West 4th Street, New York > Dubilier CONDENSER AND RADIO CORPORATION | Put on like Plaster SEMA =! \Vears like Iron ‘waterproof pfireproof -\resilient Fifth Avenue, New York Custom Tail- ors want agents to sell advertised brand all we llored to measure suits and overcoats direct siahts Ws caglesl ox cepttience seaaeel.. tia! n a 3 samples Free. Biggest “Cor Rute Brae to aeegeae”” Monae Feiloring” Go u agents. allo 0. ; | 100 Fifth Avc.. Dent, L-1. New York > noiseless A composition material casily applied in plastic &% form over practically any kind of floor. Laid Ya about % inch thick. Imperial Floor does not crack, peel, or come loose from foundation. A & yA continuous, fine grained, smooth, non-slipping & 4 surface. No crevices to gather grease, dirt, dust, & 7 disease germs or moisture. y Ideal Floor for Kitchen, Pantry, Bath Room, & Laundry, Porch, Garage, Restaurant, Theater, & 4 Hotel, Factory, Office Building, Railroad Station, ¥4 Hospital—wherever a beautiful substantial floor & Y, is desired. Several practical colors. [Full in- & Y4 formation and sample FREE of your first and v4 second choice of color. Imperial Floor Co., 337-339 Halstead St., Rochester,N.Y. rpazguem A Success for 15 Years jpam = FREE Sai: BIG SET. TELESCOPE — r/ See people and objects miles away, on land or sea, as if they were close, ; Wonder Telescope gives new pleasures to home, farm, camp, travel, 4 sport. See moon and stars as never before. ; Opens out over 3 feet long, in5 sections; measures 12 inches closed.~ Brass bound; has powerful lenses. ousands pl “Could tell color of | oi aeroplane 4 miles away.’’—Mrs. Yarbrough. aw x a? rE asa —, Provincetown Light. 28 miles away, = FREE | Sistine? !iseescs Ht ioshokccnd tat Me : hing submari 8 yard 6 miles away."’—P. H. H | handsome, sturdy miles off the coast.’’ @" etd . Read the numbers on freight care mile #! 12 in. leatherette| —P- Grush. “*Can % o Ge ° % ing Case sent REE with a) Wonder Tele- For Ford or Cheviolet We can furnish you with the latest style roadster or racing body at ices that will surprise you. bodies may be used with or without fop er windsheld or fenders, and may be enderslung {i deswed. SPORT BopDIES$ 5 \ FORD RACER 25¢ CENTRAL AUTO SUPPLY CO, 23%: Loviayists a oA = away, see mountains on moon’’— see children ie Because of fortunate purchase from large European —-> SS maker we can give you a big bargain. Be first in your = pe ‘ neighborhood; entertain your friends, Send no moneys send only name and address for telescope and ease by parcel post. On arrival deposit with Postman only $1.85 plus a few pennies postage, Satisfaction or money refunded. Order today while supply lasts, a

Page 106

Tested and Listed as Standard by Underwriters’ Laboratories o.8. Patent 1,495,582 A noiseless bulbless radio battery charger Entering the field late last year, the Balkite Battery Charger is today universally accepted as one of the most efficient and_ trouble-free methods of charging radio batteries. 1. This charger is entirely noiseless. 2. It cannot deteriorate through use or disuse. 3. It has no moving parts or bulbs. 4. It has nothing to adjust, break or get out of order. 5. It cannot discharge or short-circuit the battery. 6. It requires no attention other than an occasional filling with distilled water. 7. It delivers a taper charge, and cannot damage the battery by overcharging. 8. It cannot fail to operate when connected to the battery and line current. 9. It is unatiected by temperature or fluctuations in line current. 10. It is simple, efficient and indestructible except through abuse 11. Without added attachments the charger may also be used to charge “B” storage batteries. 12. It can be used while the set is in operation without disturbing sounds. The Fansteel Balkite Battery Charger will charge the ordinazy 6 volt radio or auto- mobile storage battery at 3 amperes, from 110-120 AC, 50-60 cycle current. Manufactured by Fansteel Products Company, Inc. North Chicago, Illinois Price $19.50 © West of Rockies $20 In Canada $27.50 At your dealer’s. If your dealer cannot supply you, sent prepaid on receipt of price Balkite ‘Battery Charger HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY The Home Shipshape - a ‘ ia’ 3 Ly 1p My Home workshop is the major factor in helping to keep my home shipshape. It is the accumulation of years of doing odd jobs and making things for myself. When anything needs doing around the house, I do it myself. If I Electric Fixtures couple of ideas that have saved me mone All the electric fixtures in the hoys were old when we moved in. They wer in good electrical condition, but the oy. side was spotted and discolored and lookeg like bad news. A can of flat black pain; made them look like the latest thing i: wrought iron. The effect wa; need some tool, I buy it with the money that will be saved, and when I have the job finished, I have the tool left as profit. By buying tools as they are needed, it is easy to own a fine outfit. The biggest help to me in keeping the home shipshape is reading POPULAR SCIENCE MONTHLY. It is a regular mine of ideas, aids, and sug- gestions on how to do almost anything. Friend Wife reads it, too, and evidently with results, for I came home one so good that I made som shades from sheet metal anj parchment and painted th metal part black to mate the fixtures. The pictur gives an idea of the effect. The other idea was to uw a broken automobile winc- shield glass as a shelf for the bathroom. The glass wa about 5 in. wide and 30 in, long, with one jagged end where it had _ broken. | trimmed off this ragged edge, made three wooden brackets, one for each end and one for day and found her calmly screwing back the top of the electric iron. A connection had come loose and she had taken it apart, repaired it, and put it together again. It works fine. Now I want to pass along to you a Flat black paint trans- forms shabby fixtures the middle, and had a cheap plate-glass shelf.—s. B. You can save money in repairs by taking proper care of your door and window screens. How to do it will be told next month. : SOMETIMES a Kitchen kitchen sink is I mprovements | placed in a corner in such a way that no drainboard can be provided without changing the plumbing. This was the case in my own home. I overcame the difficulty by construct- ing a slightly slanting drainboard as shown, 12 in. wide and 4 ft. long, with one end cut away so that no part of the sink would be covered. A narrow strip in front keeps the dishes from slip- ping to the floor, and af Ak a ae A corner drainboard a wider and general : utility box strip at the rear forms a splash- board to protect the wall from spots. The joints were made waterproof by running a piece of tape saturated with white lead where the edges come together. The board was fluted or grooved to im- prove the drainage. The legs were at- tached with small angle irons. The whole was finished with several coats of raw lin- seed oil. Brushes, cleaners, and soap are kept in a box under the sink. This is a canned- goods box, smoothed with plane and san¢- paper on the top edges, and covered on the two exposed sides with a scrap of linoleum left over from the floor. The neat ap- pearance is dependent upon the care taken to match the pattern of the linoleum where the side and end pieces meet.— AusTIN G. TRIBUTE. Patchi OccasIonaLLy it is atcning necessary to repait Concrete damaged or cracked concrete work. This is difficult to do successfully unless the following suggestions are observed: ; Use the same proportions of sand, gravel, and cement as were used in the original mixture, so that the new Work will expand and contract the same as the old concrete. Otherwise the patch wi! erack. Keep the place to be patched thor oughly wet for several hours before work- ing on it. This can be done by covering the surface with old sacks well saturated with water. For this reason a rainy spe is a good time to patch concrete, although the work should not be done while the rain is falling on it. : The place where the patch is to be made should be roughened with a hammer’ chisel if it is smooth. . cae After the patch has been applied, ti new concrete should be kept moist 42 allowed to dry very slowly. This can he managed by covering the concrete wit! wet sacks, burlap, or rags, or by usiné moist sand.—M. W. Lowry, Athens, 62 i n little ¢ It has struct from turnin conne The clear |

Page 107

ne Money, the house “hey Were C the out. nd looked ack paint thing in effect was ade some netal and inted the to match 2 picture effect. as to use ile wind. If for the ‘lass Was nd 30 in. reed end oken. | ged edge, brackets, d one for | a cheap JB. oney in of your w to do nd sand- 2d on the linoleum neat ap- she care linoleum meet.— LLY it is O repair cracked rk. This less the IE of sand, 1 in the Ww work e as the tch will od thor- re work- cove;ring iturated ny spel! ithough hile the be made amer ‘OT ied, the ist and - can be te with y using ons, Ga. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY = Sturdy Toy Motorbus Has Unique Steering Device By Donald W. Clark HIS toy motorbus, which is made mainly of wood, can be built with jittle difficulty and practically no expense. | It has no motor to complicate the con- struction. The child pushes it around from behind, steering it as he pleases by turning the spare tire, which is ingeniously connected with the front axle. The accompanying illustrations make | | clear the construction of the various parts. this is a toy that will delight little tots | The body is built up of thin wood and the | wheels are wooden disks with a cardboard | circle glued to each to represent. the tire. | Tin covers and strips of tin serve as the | fenders and runningboards, and heavy tin or sheet metal is used as shown for | mounting the front wheels. The front wheels are connected by a wire bent so that the point in the center projects down- ward and engages a slot in the first of the | two thin metal strips, which serve as steering rods. These strips are pivoted as | indicated and are moved by an L-shaped piece of 1-16-in. wire fixed to the center of the spare wheel in the rear. Turning this wheel moves the front axle to the right or left, as desired. Coming Workshop Articles OW to Make Unique Craftwork Dinner Gongs. Imitating Inlays by Stenciling Wood- work with Sunlight. How to Store and Care for Your Win- dow Screens. Constructing a Filing Attachment. ow to Keep Your Oilstone in Good Condition. hotographic Vignetting Masks Made with Films. eee Sargent Steel Block Plane Sargent Auto-Set Bench Plane just as good as new! HIS old kitchen table needs a lot of fixing—but after the Sargent Auto-Set Bench Plane smooths the dented top and trims the battered edges, the job will be nearly completed. The Auto-Set certainly does fit in at a busy work-bench. It’s so capable, keen-cutting, and easy to adjust and handle. It will last for years and years. The special chromium steel cutter is as keen as they come and holds its edge much longer than most. But when it does need sharpening, only a few minutes are required to remove, whet and replace it. You don’t have to touch the orig- inal adjustments. For the smaller jobs, for the finishing touches to cabinet work, or for getting into close quarters, youll need the Sargent Steel Block Plane. This is small in size, but big in ability. The low angle arrangement of cutter makes it particularly suitable for cross-grain work and rough or knotty surfaces. Both of these Sargent Planes are used everywhere by carpen- ters who take pride in the char- acter of their tools. Write for Plane Booklet. SARGENT & COMPANY Hardware Manufacturers 50 Water Street New Haven, Conn. © a po Jools é: Hardware “WONDER” COLD PIPE, 23;==> TUBING & BAR BENDERS HAND and MOTOR OPERATED 14 Sizes of Machines What it costs to bend pipe our way. Per bend. 1’’ pipe 5cents 4'° pipe 25 cents ’’ pipe 10 cents 6’’ pipe 69 cents ’’ pipe $1.00 a Send for Catalogue. AMERICAN PIPE BENDING MACHINE CO. S51 Pearl St. Boston, Mass. Exceptional Quality is found in every Gerstner Tool Chest a For Machinists and oolmakers A postal brings free catalog which tells about them. H. GERSTNER & SONS 509 Columbia St., Dayton, 0. | | | | tells you the secret of Success in Music in this Free Book. Send for your copy and details of FREE TRIAL, EASY PAYMENTS on any Conn instrument for band or orchestra. Ac- claimed best by worlds famous artists. G. Conn, Ltd. 931 Conn Building Elkhart, Indiana INSTRUMENTS woes) WactsT wamuracrunene

Page 108

- ! ! I j 1 I | 1 1 L} 1 ke Ss: BUILDING TR; ADES: HANDBOOK BUILDING TRADES’ HANDBOOK Only and Measures, For- mule, Mensuration, Geometric Drawing, Structural De- sign, Materials of Masonry Con- struction (stone, brick, terra cotta, lime, cements, sand, mortar, con- crete), Carpentry and Joinery, Roof- ing, Steel Square, Plumbing, Heat- ing, Estimating, Architectural De- sign, etc. 409 pages. 263 illustrations. A reference book for every man con- nected with the building trades. Contents :— Blue Prints, Weights Thousands sold. Complete—prac- tical—thorough. Easy to under- stand. Pocket size. Just fill out the coupon below— slip it into an envelope with a dollar bill and mail, and this 409-page I. C. S. Building Trades’ Handbook will come speeding to you by return mail. ‘ You run no risk Money back if desired ame coe coe ee ee ee ee es ee we we we International Correspondence Schools Box 7612-D, Scranton, Penna. I enclose One Dollar Tlease send me— post-paid—the 409-page I. C. S. Building Trades’ Handbook. It is understood that if I am not entirely satisfied I may return this book within five days and you will refund my money. BIN ININD isc hinscoepava vues buonsspvieesinvonsucnesecvonnesecebbcanpbeopebs Addre« “At dealers, or postpaid Durham & Co., 1936 Market St., Phila. for Machinists, penters and " yeaa gals Car- Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered. Ask for booklet. oem ‘Built for Service” The Pillied Lumber Co., Swanton Ohie HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Chemistry and Money .———_— = CCURATE scales are expensive to buy and quite difficult to make by the ordinary method. A delicate balance is essential, nevertheless, as soon as really careful chemical work is to be done in the home workshop. The question is, how to make a dependable scale cheaply and without taking a great deal of time. My best suggestion in answer to this question is the construction illustrated below. I am sure that the many readers who have shown their interest in the | Home Workshop Chemistry series by writing to me about this and other ques- tions will find such a seale simple to make and adequate for all ordinary require- ments. It will weigh light as well as heavy objects. The scale can be made from metal or wood strips, thin boards, wire, tin, and - Oi. a TE Dimensioned dia- gram and the com- Eleted scale below 16" K —— ee mma i2" 3" } three safety-razor blades or old knives. It should be made accurately, for a slight error will throw the entire balance out of | order. The dimensions are in inches. If a smaller scale is desired, each inch can be divided into halves, ta!sing a hali inch as the unit of measurement. The scale should not be made smaller than half size. The scale shown consists of a base 22 in long and an upright about 10 in. high. The base and upright must be firm. The top of the upright carries a razor blade, A, firmly fastened in position, edge upward. On this is placed a wooden rod, E, that is 16 in. long and about 14 in. square. A tin U or V is fastened to the rod 1% in. from the end to carry the weight pan and 10 in. from this point an- other V of tin is fastened, this time on the under side. This V rests on the knife A. One inch from this point another V is fastened on top of the rod, while 4 in. from this last point another and final V is attached. These V’s are bent from tin and nailed to the long beam. The baseboard has a razor blade placed | 20 in. from a line drawn vertically through the knife of the upright. This (Continued on page 109) Home Workshop | Simple Formulas that | Will Save Time | | Layer Wound and Layer Insulated— Powerful Magnets These are distinctive features of HEAD SETS AND LOUD SPEAKERS Layer winding means that the coils are wound in layers of wire, with insulating ma. terial between each layer. This ensures great resistance, enabling the instruments to stand up under the highest plate voltages. *“‘Powerful Magnets” refers to the great strength of the magnets used in our instru. ments. Strong magnets are necessary to bring in the long distance signals with their full volume and clearness. Stromberg-Carlson reception apparatus have magnets that are exceptional for permanent strength. Ask your dealer STROMBERG-CARLSON TELEPHONE MFG. CO 1060 University Avenue Rochester, N. Y. To Each Purchaser O/ a A 24-Volt“B”’ Storage —s given FREE with each purchase of a WORLD i. Storage Battery. The WORLD Battery is fa; mous forits guaranteed quality and service. Backed by years of Successful Menatnctare and Thousands of Satis: sers. You save 607, Prices That Save. and Satisfy Auto Batteries Radio Batteries 6-Volt, 11 Plate$12.25 6-Volt, 80 Amps. $10.00 G-Volt, 13 Plate 24.25 S-Volts 209 Amps. 42.50 6-Vok, 170 ps. i 22-Vok, 7Plate 17.00 6-Voit, 140 Amps. Shipment Express C. O. D. subject to examination. 5 per cent discount for cash in full with order. 2-Yr. Guarantee Bond in Writing With Each World Storage Battery Proves satisfactory World perform . Mall this ad with your name and address — we wii isnip, pues day order {s1 on ceived; and give you your chol-e “B’’ Ft e B ome nickle finish Auto Ssotlite, FREE. Write TODAY. WORLD BATTCRY COMPANY 4219 So. WabashAve. Dept. 7 CHICAGO, ILL. This FREE a “Cane at takes the piece of dry Song aesdis "the coy battery “ia advanins (To those who some nickel fin‘sh Auto & sure to specify w: GIVEN FREE zo introduce new ard a a il we hy BD of the *‘B’’ Bat- is wanted.) blad the boal poir side the for? bal: bri¢ as é cas

Page 109

sures its to great istru- bring r full irlson t are IN 0 enue ¢ || HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Qld Table Leaves Utilized in Building a Bookcase AVING a number of old table leaves, we sawed off the little knobs, poured wax in the depressions and used the pieces to build book shelves as shown. They were enameled black and decorated with bright flowers. These were painted on the black surface in such a way that tiny buds concealed the wax depressions where the knobs on the edge had been re- moved.—M. L. CHERRY, Sandusky, Ohio. Home Workshop Chemistry (Continued from page 108) blade supports a tin V placed 1 in. from the lower end of the bridge, D, which is a board 17 in. long. Exactly 15 in. from this point another V is placed on the under side of the arm and it is connected with the beam by a wire arm, G. The upper bridge arm or weighing plat- fom, C, is a board 19 in. long. It is balanced by a knife firmly fastened to bridge D exactly 3 in. from the end knife, asat K. A V is used here as in the former cases, and another V is fastened to the weighing platform, 16 in. away. This V is connected by means of wire F tp the V on arm E. The seale pan, B, is fastened to beam E by means of the V at its far end. The support, H, prevents the beam from swinging too much and indicates when the scale and the pan are balanced. The swing should be very small, not more than 3¢ or 14in. The length of the two wire arms F and G are determined by the height of the up- right and the height of the knives. The arms E, D, and C must be perfectly hori- zontal or the scale will not work properly. To balance out the scale, add slight weights to either scale pan B or bridge D, so that beam E is in equilibrium. Then if 1 gram is placed in B, 10 grams will be balanced at C. This means that a weight placed at B will balance another weight at C, which is just 10 times as heavy. By reversing the process and placing the | weight on C and the object to be weighed at B, the object will be exactly one-tenth | the amount. _ The decimal arrangement gives a flex- ibility to the seale that is desirable in the home laboratory. The necessary weights tan be purchased from any scientific druggist supply house. Your own druggist usually will be glad to get them for you. Purty may be kept soft by covering it | with water. To prevent the water from ‘vaporating, add a few drops of lubricat- | ing oil. This will form a surface film. i. | | "Experience is the Vital Factor in Excellence” The first “talking machine” became a finished reproducer of speech and music only by years of experience devoted to gradual development. | GNDOMPSsSON SPEAKER Fourteen years devoted to making radio products furnished the background from which the Thompson organization has perfected the Thompson Speaker. | Each part of the Thompson is the result of the best | known engineering experience and these parts are assembled in a manner that is possible only to experi- | | enced radio engineers. are seven reasons why you should not “Just get along” with an ordinary speaker_when you can get a Thompson. $35. The 7 superior and distinctively Thompson features | } | | | * * 2 > * = Few users ever need all the range and power that the | Thompson Neutrodyne will deliver. Made by the same organization. $150 without tubes or batteries. Re R. E. THOMPSON MANUFACTURING CO. Manufacturers of Radio Apparatus for the U. S. Army and Navy and numerous foreign governments 150 NASSAU STREET + » NEW YORK, N. Y. FACTORY: JERSEY CITY, N. J. TWENTIETH CENTURY | Book of Recipes, Formulas and Processes This book of 800 pages is the A mine of information, up-to- most complete Book of Recipes date in every respect. Con- ever published. Hints, Helps, tains an immense number of Practical Ideas and Secret Proc- formulas that every one ought esses covering every branch of to have that are not found in the useful arts are given. any other work. Price, $4.00 Popular Science Monthly, 250 Fourth Ave., New York

Page 110

110 PP HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY nana" Oooo S22 Need oo Nas ee NTT SOOM A: ervequnnnece? el — — — Coupler (SW 21), vd OSCILLO. COUPLER FREE \») US | SUPER-HETERODYNE ne TeAD Super-Heterodyne are the product of proven engineering skill and long experience. RECEPTRAD parts in the construction of your super-heterodyne you can confidently expect results worthy of the circuit. Ask to see the RECEPTRAD UNITS at your dealer’s. Each Outfit contains 1 Oscillo (H 34), 3 RF 1716 Transformers, 1 Audio Transformer (AT 3), 1 Audio Transformer (ATX), 2 Bypass Condensers 1 Mf. (G 1000) and sells for only $53.50. The Greiff Super- Heterodyne Manual, a complete treatise, with layout and diagrams, $1.50. Complete Blueprint No.1 of the Greiff 8 Tube Super if you send your dealer’s name and address RADIO RECEPTOR (0. T Mt Y pau aect PTRAG Rene euoenenneunetneatasunanen cas cartunane PEO AAA Or parts When you use ~-'s = "4a +o 1 Tuned Filter Coupler > > ot od ot eS ve ‘a "a*.™ MOODARAAA = . ‘4%. © aaa? ‘ S9 Bank St. © New York City A new twenty-four page booklet will be sent ¢gra- tis, to those interested in building their own receiv- ing sets. A simplified method of construction is described. Illustrations and dia- ¢érams. EISEMANN MAGNEYTO CORPN. Free Money . s iviotorcycle Bargains a, SAVE 25% to 65% asi on Slightly Used Motorcycles, Ace, Indian, Excelsior, ® Harley-Davidson, Cars, Johnson Motor Wheels, Evans Power Cycles, Bicycles. Bargain Dept. 928 and Rebuilt Cleveland, Side Send for Bulletin and Saving Message, listing hundreds of bargains in used, rebuilt and new machines, supplies, accessories, e , etc. AMERICAN MOTOR CYCLE CO. 2017 W. Chicago Ave. CHICAGO On Request William N. Shaw, President 165 BROADWAY, NEW YORK Over 250,000 Now In Use We have proved to hundreds of thousands of msufferers from hernia (rupture) that to obtain lasting relief and develop a natural process for betterment comes by wearing a Plapao-Pad. This patented mechanico-chemico device can do the same foryou, The wearing of an improper support aggravates rather than improves the condition, The Plapao-Pad can and does aid the muscles in giving proper support, thereby ren- dering efficient aid to N strength to the weakened muscles. adhesive there is no slipping and shifting of # pad with resultant irritation and chafing. Most comfortable to wear—no delay from work. Awarded Gold Prix at Paris, Ss ; E aee No Money: We will send you a trial of PLAPAO LABORATORIES, Block 716 St. Louis, Me. STOP USING A TRUSS Do Away With Steel And Rubber Bands pin Ri d and Whatis With. in It That Counts elk 4 vet—easy to apply. ature in _restorin Being self- at and Grand you pay nothin i for this trial rite for it today. also inf ‘ormation. Se How to Aline Auto Engine Connecting Rods By Ray F. Kuns Principal, Automotive Trades Schoo! Cincinnati, Ohio A MOTORIST brought his car jnt, the shop not long ago and con. | plained about the noise made by the valve lifters. He asked that the a be gone over. One very bad valve lifter | with a flat roller was removed, the bear. | ings were taken up, and other work done, | The owner then left for a trip covering | several states. | When he returned he said that the car | had run nicely, but that there was another | bad lifter noise. “The first 200 miles I drove as you told me, at not more than 25 miles an hour,” he explained. “‘After that, I speeded up a little and then I noticed that the old lifter noise was back. It doesn’t seem to do any harm, but I do not like the noise. I want to leave the car and have you Checking aline- put in another new mentonspecialjig | lifter.” A mechanic found that the lifters were THICKNESS GAGES | all right, although the owner could be ex- | cused for the mistake, since the noise was | practically the same as the first one he had | experienced. The repairman decided that it was a wristpin knock, and so it was, but not due to a loose pin. In doing the engine over- haul work the first time, the rod in No. 2 cylinder had been sprung out of line or | the bearing improperly scraped. At any rate, the rod set at an angle rather than plumb, and when the explosion came, the upper end of the rod was snapped out against the piston boss, producing a knock. This is the sort of noise hard to find and only one of the troubles likely to be experienced when piston rods are not properly alined. Rods are thrown when pistons are out of alinement | removed from the cylinders or other | work is done on them. They always should be put on an alining jig or tested by other means before being replaced in the en-| gine. alining rods may be used when a jig is not available. A square set on the machined top of the crankcase and along the skirt of the piston when the piston is on dead Using square to test straightness alinement. Another way is to clamp the to test the skirt. and rod assembly in relation to the cylinder is to assemble the job with the piston in the cylinder, but without the (Continued on page 111) —_—— center will indicate the degree of mis | rod bearing on an arbor and use the square | A splendid method of testing the piston | Several methods of |

Page 111

ar into d com. | by the > engine Ve lifter | ne bear. rk done, overing the car another cial jig | TS were 1 be ex- ise was he had was a not due @ over- 1 No. 2 line or | At any | or than ne, the ed out cing a ard to kely to re not ement | n the | other | them. | should lining | - other being | e en- | | ods of | ay be} is not | quare | shined | skirt dead | mis- | p the quare yiston | , the h the + the HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY How to Aline Connecting Rods (Continued from page 110) | rings. Have the cylinder head removed ‘and hold an electric light under the ‘eylinder to be inspected. If the rod is properly alined, it will be possible to see a ring of light all the way around the piston in the cylinder. If the rod is misalined, the piston will be cocked in the cylinder and it will be impossible to see past it lexcept at certain points where it is not | binding. When a rod is not properly alined it | must be bent or sprung until it will allow ‘the piston to fit the cylinder correctly. | Otherwise the cylinder will wear unevenly. In bad cases it will be scored by the pis- 'ton, and bearing trouble will develop at | both ends of the rod. The piston pin is far | more likely to be loosened from its an- | chorage, and piston pin scores result. Merely bending the rod will not always | aline it and the piston. In some instances | jt is necessary to give the rod a slight off- | set by making two bends. A large monkey | or adjustable wrench is the usual tool | used for correcting rod trouble of this sort. Determine which way and how much the job is out, and apply the wrench to_ spring the rod. After care- fully alining and testing outside the engine cylinder, it is wise to make the lamp test as a final check. When _ scraping rods, many mechan- | ies prefer to get their final impression on | the rod bearing by bluing it and rotating | the shaft while the piston is in position in | the cylinder. This frequently will show | the workman that he has not scraped the | bearing evenly and tell him just where to | apply the scraper. | Another essential test in alining a rod is | to see whether the axis of the pin and the Checking parallelism of rod journals | shaft journal are in the same plane. If | they are not, there will be a twisting and | binding movement imparted to the piston as it is moved up and down. The piston should be removed from the pin and the | pin replaced in the rod. By clamping the rod on an arbor, it is | possible to sight the pin and arbor and | get an approximate alinement. The best | practice, however, is to use an alining jig | that has parallel surfaces that the pin |; must strike when the bearing end is | damped on the fixed arbor. Workmen sometimes feel that because | care has been used in disassembling and _Teassembling, things must be right. Factories long since have learned, how- ever, that, no matter how carefully parts are machined and fitted, every possible | Just | test must be made for alinement. such methods as described and illustrated here are used to provide the quiet, efficient motors turned out in automobile factories. HE next article in Mr. Kuns’ series for the motorist whe makes as many ‘f his own repairs as possible will be on fitting new piston rings. elite | } = SS tS ™. ) te “ L299 of a Rend! RYE aE PUT AY Zn AS Why thousands of radio fans enjoy him Because thousands of storage bat- teries are on the job, brimful of energy, gaining clear, satisfying radio reception for every word and inflection. With a Tungar, the carefree bat- tery charger, in your home you can keep your battery tuned up to get every single note of music, every recitation, speech or song. Tungar is one of the many scientific achievements con- tributed by the G-E Research Laborato- ries toward the won- derful development of electricity in America, Tungar Battery Charger op- erateson Alternating Current. Prices, east of the Rockies (60 cycle Outfits)—2 ampere complete, $18.00; 5 ampere complete, $28.00. Special attachment for charging 12 or 24 cell “‘B’’ Storage Battery $3.00. Special attachment for charging 2 or 4 volt “A” Storage Battery $1.25. Both attachments fiteitherTungar, Tungar charges the battery over- night from the house current. Sold by Electrical, Auto-accessory and Radio dealers, CHARGER} Tungar—a registere] trade mark—is found only on the genuine. Look for it on the name plate. Merchandise Department General Electric Company a Bridgeport, Connecticut oy GENERAL ELECTRIC 48 E-10 At the low prices shown below you get the effi- ciency of sets costing three times as much. ; These radio frequency receivers pick up stations over 1,500 miles away under good conditions. Operate either on DRY CELLS or storage battery. Cabinets of solid mahogany and workmanship the finest throughout. Order direct or send for bulletin. Two tube outfit, as shown above, headphones only $29.50. Four a for loudspeaker or head- iS | phones $54.5 DEALERS __ write for propos ’.von quickly-it’s a winner THE MIDWEST RADIO COMPANY 808 Main Street Cincinnati, Ohio EasytoDraw Cartoons When Shown in the RIGHT WAY Some of the cleverest cartoonists and comic artiste learned how_to draw in their spare time by follows Cartoonist Evans’ Simple and Easy to Learn Meth and are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans see it you have ability and receive the Portfolio of Cartoons and full details about the course. It is not expensive. THE W. L. EVANS SCHOOL OF CARTOONING 825 Leader Building Cleveland, Ohie

Page 112

He Climbed... 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 Pri ioe Method, he was earning only $60 a month, was married and had also a little di 1ughter 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 Az7z/ 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 gre . 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 szccess. 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 ge -t the facts. We will promptly send you com- plete inform: 1tion regarding the opportunities for men “ uined in Higher Accountancy, also a copy of that inspiring book, ‘*Ten Years’ Promotion in One.” “Ge this book,” said a prominent Chicago executive, even 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 zmwportant, Mail the coupon xow. a VOU e COULON = —=—— = LaSalle Extension University The Largest Business Training Institution in the World Dept.983-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 yo ur book, Ton Years’ Promotion in One,” z all without o Higher Accountancy Training for position as Comptroller, Auditor, Certi- fied Public Accountant, Cost Accountant, etc. Other LaSalle Training Courses LaSalle is the largest business training institution in the world. It offers training for every important business need. If mcre interested in any of these courses, check here: Titian Managemesit O Modern Salesmanship OTraffic Management ORailway Station Management OLaw— Degree of LL.B. OcCommercial Law O Industrial Management Efficiency O Modern Business Corre- spondence and Practice OBanking and Finance O Modern Foremanship and Production Methods OPersonnel and Employ- ment Management OExpert Bookkeeping OBusi-:ess English oc cial s h OEffective Speaking Oc. P. A. Coaching

ae ce cc .. | this jointer, I estimate, for about $30 and tie : have a machine that with care should Prescnt POsItiOn.....<..<-2<.<<52.--<<5-0<5<5--~e~ ses nenscconsencens baat @ Vifetine. Address scuvesececcnenece HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Homemade Metal Tray Aids in | Sorting Screws Quickly | | N LOOKING for odd size screws or | other small parts in a miscellaneous | assortment, much time often is lost in | returning the collection to its container, | and frequently shavings and dust are swept from the bench top into the con- tainer along with the screws. These difficulties are overcome’ by using a pan of the shape shown. Screws may be spread | on it and when | those of the right size have been found, the remainder can be poured back into the container with one rapid mo- tion.—C. E. WEIBEZAHL, Syracuse, N. Y.

Replacing screws in glass jar container

How to Construct a Jointer (Continued from page 80) chase a knife such as that shown in detail D at a low price, so that it would hardly pay to take chances of losing a homemade knife while tempering. If the safety head is used, the knife blades will come as part of the head. The four holes drilled through the bot- tom members and marked F are used for fastening the machine to the bench. A hole about 6 in. square is made in the top of the bench to allow the shavings to drop to the floor. The motor may be located beneath the bench and the belt brought up through another hole large enough for it to pass. While I have not shown a loose pulley on the countershaft, it would be an easy matter to put one on and, as the driving pulley for the head is on the outside of the side members, a belt shifter could be attached directly to the bottom member to which the countershaft bearings are fastened. The 2 by 134 in. flanged pulley should be keyed to the shaft, as it would be im- possible to get more than one setscrew in the pulley. The key need not be larger than 3/16 in. square, but should be well fitted and driven home snugly. The same is true with reference to the countershaft pulleys. Care should be taken to see that the pulleys are true and well balanced. One point in regard to the wedges used forraising and lowering the table should not be overlooked. They should be made so that the grain of the wood runs with the wedge edge. This will prevent rough edges from rubbing together. The surface should be well greased. Before starting the machine, see that it is thoroughly oiled. Use an endless belt, as a laced one running at this speed will cause a great deal of vibration and in time tend to loosen parts of the machine. It is very important to bear in mind that the table and cutter head must be true with

| F Impre Aid 1 | BUR G ESS | pyAV | di BATTERY { | Meee N's SCUST pa now Pt net ce design onceal tion of These ary ar able t specla i | able. i RESEEE in buil . Rr B The A Vertical attery BB ia: . . 1¢ e Upright in Shape | aay’ — Upright in Use | gouge, | an ort HERE weight, table or cabinet space \ Ify is a factorin your selection of Burgess , planir : Radio “B” Batteries, buy the Burgess ver- will | tical “B” No. 5158. | nomi _ Itisright at homein anyposition in your mill | ' cabinet. Its sturdy compactness is almost | knive a necessity in portable receiving sets. | out 4 Its height, width and weight coincide the ¢ exactly with the double strength Burgess rack, Radio “A” Battery. You are sure to be to i ~ pleased with both the convenience and suffic service offered by such an assembly of ail “A” and “B” Radio Batteries. east '“ASK ANY RADIO ENGINEER” es mole BURGESS = |:

RADIO BATTERIES each BURGESS BATTERY COMPANY - Engineers - DRY BATTERIES - Manufacturers pap FLASHLIGHT - RADIO - IGNITION - TELEPHONE pial General SalesOffice: Harris Trust Bldg., Chicago init Laboratories and Works: Madison, Wisconsin on In Canada: General Offices and Works, Niagara Falls, Ont. R or] dry alec lun the bla per acoun touts 11] if wae. Hy . = ‘

start your own busi ieiorus rT command a larg: salary. Send for my unusual offer. Ts Rely temporary. Act at once. A postal international Studios, Inc., Dept. 13-66 3601 Michigan Ave., Chicago, U. S. A. Professional Camera FREE!

each other in order to do perfect work. If reasonable care is taken in purchasing | the materials, one should be able to build |

Clear xe" Your Skin Can Be Quickl Cleared of Pimples, BE a Acne Acne Eruptions on fe face or body, Barbers I itch Pores and =x or Shiny = FREE (23225 © retest noe | E.S.GIVENS, 153 169 Cheaieal Bldg., Keneas City, Mo.

Page 113

ery. space Tgess , $ ver. your most ts. ncide rgess o be - and ly of ER” HY Irers HONE icago pnsin

Improved Combination Racks aid in Playing Chinese Game | By S. W. Blanchard pave experimented with several |

different types of accessories for the ‘now popular Chinese game, I evolved a “design of rack that not only holds the | concealed tiles, but also the exposed por- “tion of the hand, as well as the counters. These combination racks make unneces- sary any other equipment and are prefer- whle to those built into the edge of a special game table because they are port- able. They also serve as straight edges n building the wall of tiles straight. "The racks are made as shown from any dear grained, soft wood. A combination plane is the best tool to use, but they ‘may be made with | gouge, chisels, and an ordinary plane. If you are near a planing mill, you will find it eco- nomicalto havethe mil] pick out some knives that will cut a molding to the design of this rack, or very close to it, and have sufficient molding machined to make several sets, each of which will require 6 lineal ft. The molding, whether hand or machine made, is sawn up into 16-in. lengths. | A pleasing finish is obtained by giving each rack two coats of black shellac, each lightly rubbed down with very find sand- paper and oil, and two more coats of plain shellac, also rubbed down. Red initials representing the winds are painted on each rack in Chinese style. Black shellac may be made by mixing | dry powdered lamp- or bone-black with alcohol, being sure that there are no lumps, and then adding thick shellac to the mixture. There should be enough black in the mixture so that the shellac is perfectly opaque. A good profit may be made by dispos- ing of the racks to friends, or the sets may be used as gifts. EXPOSED TILES

Combination rack

Connecting Radio Jacks for Several Head Sets BY USING radio jacks I have been able to connect instantly as many as four pairs of telephone head sets with my radio receiver. The method is shown in = the accompanying

seNOCNO4 NOS diagram. Num- bers 1 and 2 are double - circuit jacks, of which there can be as many more as de- sired. Number 3, or the last jack, is a single-circuit. Solder together the center sorings of | the double-circuit jacks, as at Nos. 4 and te If the circuit calls for a telephone | eee, place it ahead of the jacks, as atNo. 6. A double-circuit jack may be used at No. 3, but the center spring must left open.— THEODORE ENGEN. NO1 NOZ NOD Wiring diagram

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 4 at When you stop for the night Throw up an aerial and tune in just as if you were at home HERE is no reason why you should de- prive yourself of radio entertainment when you are away on a vacation. If your home set is too large and bulky, you can easily build a small vacation set you can carry anywhere. The cost of your vacation set will be comparatively small. The battery of your car will furnish the necessary electrical current, and if you have a home set you can take a tube and the “B” batteries from that. You should use the same care in select- ing parts of your vacation set as you used when you built your home set. Buy de- pendable instruments and then mount them on a first-class panel. Use a Celoron panel and you help your instruments do their best work. Celoron, a bakelite material, is one of the finest insulating mate- rials known. It has high dielectric strength and great resistance toatmosphericattacks. CELORON A BAKELITE PANEL You can drill it, saw it, tap it, and bore it — and it does not buckle, warp, or crack. It is practically indestructible. Celoron panels have been approved by the U.S. Navy and the U. S. Signal Corps. They are used by the best radio manufac- turers and by thousands of radio fans. You can buy Celoron Radio Panels in three beautiful finishes—black, oak, and mahogany. These do not lose their lustre or become discolored. Practically all good dealers handle Celoron Radio Panels. Send for free booklet If you will clip out the coupon below and mailit to us, we will send you an interesting booklet entitled, ‘‘ Getting the Right Hook- up with Celoron.”’ This little book is full of helpful suggestions for building and operat- ing a radio set. Send for your copy now. It is free, © Diamond State Fibre Company Offices in Principal Cities Bridgeport, Pa. Toronto, Canada—London, England

If you want to build a beautiful cabinet use Vulcawood—the new cabinet material. If your dealer has not stocked Vulcawood, write us. We will send you a pamphlet tell- ing you how to make a Vulcawood cabinet and will give you the address of the nearest dealer, who sells Vulcawood.

Diamond State Fibre Co., Dept. R, Bridgeport, Pa. . Please send me without charge a copy of the booklet, ‘‘Getting the Right Hook-up with Celoron.’’ My radio dealer’s name is: MOMMA sas i 5) Sl cys ee) beetle eral tv ces ealalih’ ena hie ae ae MODI hoe on de <i an tats oe asa ul Wah halal he er

ADDING MACHINE Adds as rapidly and accurately as a 5S ; $300 machine, yet fitsthe vest pocket. i 5 Mechanically perfect. Easy to oper- —s —— —

ate. Everyone who uses figures should own one. Counts Up to 999,999,999 Totai visible at all times. A pull of the finger clears it. Doa't carry a pocket full of pencil stubs and scrap : paper Fo venewuig. Caste aVe-Po-Ad. 4 end no money. 10 Days Trial Just name and ad- dress and we will send machine postpaid. Pay postman on delivery $2.95. Use it for 10 days to prove it does all we claim. If not perfectly satisfied we will refund your money. Limited supply. Order today. Reliable Adding Machine Corp. 170L W. Washington St., Chicago, Il. Here’s a money maker for you. Every- wants profit. one. Splendid Write for special offer, DO IF NOW.

EAT Without Coal Amazing invention does away fy with coal or wood. The In- B stant-Gas Oil Burner sets in firebox of any stove or furnace; burns 96% air and 4% oil, Gives three times the heat of coal and cheaper. Better cooking and baking. Installed without damage tostovein five minutes—tofurnace in an hour. Over 160,000 in use Sold on money-back guarantee; 30 DAY FREE TRIAL andlow introductory price to first users inlocality, Write todayfor Free ‘ Book, ‘“‘Scien-

ing.’”” Men- Safety Valve tion whether Approted by forstoveor Underwr'ters Laboratortes furnace. Internstional Heating Co. Dept30-Y,117S.14thSt.,St.Leuis,Mo : » k. Wri P Agents: jor ico" Sample Ofer

Page 114

114

Millions will ™ oe CETEGFOR-AMPLIFIER MODEL C299 PATENTED lage.

Broadcasting of the Presidential Campaign

This year, for the first time in history, it is possible for millions ot United States citizens to hear our statesmen in their oratorical battles for the honor of the presi- dential nominations and elections. Radio has destroyed the sinister isolation that in decades past has caused strife, misunderstanding and even civil war.

CUNNINGHAM TUBE PRICES Now in Effect C-301 A—5 Volts 1-4 Ampere filament, $5.00 C-299—3 Volts amp. Dry Battery Det. and Amp. - $5.00 part in the operation of your re- ceiving set. Enjoy this wonderful opportunity of Radio broadcasting. Specify Cunningham Radio Tubes for clear reception. PATENT NOTICES. Cun- ningham tubes are covered by -06 patents dated 2-18-08, 2-18-12, 12-30-13, 10-23-17, 10-23-17 and others issued and pending. Li-

Home Office: 182 Second Street, San Francisco

Radio, the Wonder-Worker, has C-300—65 Volts Gas _ censed for amateur, experimental brought the forty-eight States x jontent Detector, $5.00 and entertainment use in radio 5 into a radius no larger than a ahd BY Volts. .25 communication. Any other use j Colonial town-hall. A new politi- Te blend: ae will be an infringement. cal era dawns, thanks to its magic. Special Base - - $5.00 Cunningham 40-page Data 4 The vacuum tube has made C-12—Similar to C-11 Book fully explaining care and |f; possible this broad and far reach- with standard operation of Radio Tubes now ing application of radio telephony base, - $5.00 available by sending 10c in 4 and plays the most important stamps to San Francisco office. 4 “ Ethno 2 Branch, Chicago Branch, New York

Wrestling Book FREE Learn to be an expert wrestier. Know scientific § wrestling, self-defense, and tee Hoyt Develop a eplendid physique, and have per ect bealth. Join thie popular school end learn by mail, The famous world’s champione—the marvelous Frank Gotch and Farmer Burns offer you a wondertul rtunity. Wrestling le easi quickly learned at home je Med and Dboys write now for splendid free book. [POW HEALY Leora all the eclence sod tricks. Be able to handle H ig men ease. cece! i@ wondertul offer poe NOW. Send for tree book today, stating yourege. Farmer Burns School of Wrestling, 1786 Ramee Bldg.,

Omaha,Nebr.a

Start permanent business. Every- thing furnished. Work anywhere, only table room requir- ed, $25.00 to $75.00 weeklv o erating Tangley Art Portrait Landscape Painting Business. Nc experience necessary. Hundreds successful workers. Quickly learned tn 10 lessons. Free booklet. Tangley Company Main, Muscatine, Iowa

improved New Model 3; H-P PULLS OVER 2 H-P (Burns Kerosene or Gasoline) You can get any size OTTAWA from my factory atlower prices and on easy monthly payments, Earn its cost as you use it. NO INTEREST TO PAY 3 core iss nee touay, Base ine to start. Sizes 144 H-P to22H-P. Write for new FREE k- ‘How to Know Better Engines.’ ’Send name oncard todaya, OTTAWA MANUFACTURING CO. 1951-B ming st. Ottawa, Ka Desk 1951 Magee Bidg. Pittsburgh, Pa.

BLANK CARTRIDGE PISTOL tection against Burglars, Tramps, & Dogs PRICES

Well made and ef- fective; modelled on anger to life. It_ takes standard .22 mai \ Varteloges ey At ) - Superior qua < s' . Blank Cartridges by. express, 50c per T00: tee ox Johnson Smith & Co., Dept. 157, Racine, Wis.

SCREW CAP

ITS THE POINT. imported from Japan. Money refunded if you don’t think it’s the best pen quantity price fist and distributing plans. F. $P0

Sellsfor $1.25. Agent’s Sample 65c.! PEN RETAINER FITS INTO BARREL ABSOLUTELY \_ FRICTION-Ti PREV NONCLEARABLE GHT PREVENTING TWISTING OF TUB:

HAS EIGHT GROOVE “It makes Carbon Copies.” Guaranteed for 1 ict ou_ever wrote with. S & CO., 199 S. 4th St., Lesueur Center, Minnesota New Self-Filling Bamboo Fountain Pen with Stylo Point

- e == S FOR INK TO FEED ustlers Making $20 Daily! Up to 150 per cent Profit.. Send for

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Brass and Copper Tubing ( (orree tubing can be shaped jn ya, ous ways if one knows how to dy « | Brass tubing—that is, drawn-brags tubing | —can be handled in the same way “f some extent, but it will not stand as my: stretching and bending as copper, _—| Before starting, anneal the tube tho. oughly by heating it red hot and quencs | ing in cold water. If there is much hame_| Tricks that Aid in Shaping mering or forming, anneal it at interyak | | 8 | during the process. A job that looks difficult, but is not Dare ticularly so, is making a bulbous enlarge. ment in a tube. Plug the tube with lea at the place where the enlargement is to be made, either by pouring in melted mets| | or by driving in a cylindrical plug, anj then force the soft metal outward by pressure against the ends of the lead plug The simplest way to apply pressure js ty slip the tube over a steel rod held firmly in a vise, and insert a similar rod through the other end, using the upper rod as 2 :

BLOCK _ .

SWELLING A TUBE MAKING A FLANGE How a bulbous enlargement is formed, and a simple method of making a_ flange punch. The lead is removed after the job is done by melting it out. This cannot be done where the tube is too long. It is a good idea to fill a tube partly with melted lead or Babbitt metal when flanging an end, chiefly because it prevents the tube from becoming deformed just back of the flange. Leave enough of the tube free of lead to allow the flange to be turned over. In a piece of brass or iron drill a hole into which the tube will fit tightly, and see that the hole is square with the surface of the block. Start turn- ing over the flange by belling out the end of the tube with a conical punch, and then use a round-ended punch and the drilled block to carry the work along. Finally flatten down the flange on the block with the hammer. In the last stages of the work re-anneal- ing will probably be necessary. While this will melt out the lead filling, it will not matter, because the tube will be sup ported by the block. Do not expect to be able to make a wide flange at the first attempt. A good idea is to split the die block so that when it is gripped in the vise the tube will be nipped and held securely: Bending can be done perfectly, 1 matter how complex the bends, if the tube is filled with melted lead; the tube wl bend like a soft rod and will not flatten no buckle.—H. G.

trated no @ sharp As board tened baseb | panel long | pinne is to covel shaft with lead Totor TI varic Tece

Page 115

a aping | bing | : | d IN Var}. | ’ to do it,| aSS tubing > way, to| d as much | er, | ube thor.|

uch ham. > Intervals | is not par. IS enlarge, With lead ont is to be ted metal plug, and tward by lead plug, ssure is to eld firmly d through r rod as a III Punca | We!

A FLANGE ned, and a flange ter the job his cannot » long. ibe partly \etal when it prevents rmed just ugh of the ange to be iss or iron be will fit is square Start turn- ut the end , and then the drilled Finally block with re-anneal- While this it will not 1 be sup- cpect to be t the first it the die- in the vise d securely. fectly, no if the tube . tube will flatten nor

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

ae e Unique Variometer with Flat Coils Allows Close Tuning WO thin boards serve as forms for the T coils of the simple variometer illus- trated, which can be made at practically no expense and yet ‘gives exceptionally sharp tuning. A small block is glued across the rotary poard, and the stationary board is fas- tened by means of another block to the paseboard of the receiving set behind the nanel. A wooden or brass shaft 314 in. long passes through both boards and is pinned with a nail or tack to the one that ito turn. A fiber washer separates the two boards. Around each is wound 20 turns of No. /99, 22, or 24 single or double cotton-

Hae koe <I] Ya xYo"x2"| eka 6 a 1 Ya BRASS OR Oa K. WOQD SHAFT - a axa x4" STANDARD One of the coils can be rotated and also moved away from the other coil covered wire, 1 turns each side of the shaft. The coils are connected in series with a flexible connector and a flexible lead is provided for the wire from the Totor. The variometer is used as any other variometer, the knob being turned to the right or left to tune. For still sharper tuning, the knob is pulled out so that the coils are separated more than normally, the shaft having been made long enough to allow 1-in. motion in and out. The same idea can be applied in the construction of a variocoupler and for various other uses in building experi- mental receiving sets, and various refine- ments can be made, such as providing a top for the rotor, impregnating the wood with hot paraffin before winding the coils, and using hard rubber or fiber in place of vood.—_ JAMES GREENWOOD, Dunbar, Pa.

Coilspring Serves as an Aerial \[ovING to an ““ apartment recently, I found I ‘ould not erect an utside aerial for ny radio receiving *t. I used, in- ead, an indoor “rial composed of 4 lengths of No. “hard brass wire, tach 50 ft. long. The wire was Yound into a spring 14 in. in diameter and ‘tung from opposite corners of the room, % shown, being fastened to the molding with fiber hooks and insulators.—W. H. F. COLLSPRING AERIAL — 4 = io. a

RADIO SET

| gndappealing that you begin in your | gurprise your friends by playing

115

~WLDouglas » $5,°6,°7 & §8 SHOES BOYS AT $4.50 & $5.00 Women of fashion should know that we have in our stores a most attractive display of distinctive, up-to-date Women’s shoes in exclusive styles which appeal to those who desire stylish and comfortable shoes at reasonable prices. ~ x

$6 | 7 37.00 Fall Style wae” New Brogue for soca = X for Men g In Cherry Red Russia. Also in Velour Calf for women with soft box in Black Velour who prefer Black leather. Calf. Also in light Russia Calf. WEAR W. L. DOUGLAS SHOES AND SAVE MONEY FOR 38 YEARS, W.L. Douglas’ name and portrait have stood for quality, for economy and for satisfactory service. W. L. Douglas shoes are exceptionally good values. Only by wearing them can you appreciate their superior qualities. Such quality, comfort and service are rarely found in other makes at our prices. A late broad-toe last THE EXCLUSIVE, smart models, designed especially for young men and women, are the leaders. Seldom have you had the opportunity to buy shoes of such wonderful value as you will find in the W. L. Douglas $7.00 shoes in our retail stores in the principal cities, and in good shoe stores everywhere. WHEREVER YOU LIVE, demand W.L. Douglas shoes. They are sold in 120 of our own stores and by over 5,000 shoe dealers. For economy and dependable value, wear shoes that have W. L. Douglas’ name and the retail price stamped on the soles. The stamped price guarantees the value. If they are not for sale in your vicinity, write forcatalog. ‘S W.L. Douglas Shoe Company, 124 Spark St., Brockton, Mass. 2, 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 jt 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 a special offer to agents. Write Sales Manager, J. S. Hansen, 336 West 47th St., Chicago

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. Send 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. Room 202 Victor Bidg. Washington, D. C.

Home Protection

: with an neem a “PLAY ALE THE L HITS ASTRA } After Your FIRST LESSON You Automatic Will Play a Complete Selec- tion. We Guarantee That-- Our method is so simple, interesting will cost little Nearly every man wants a gun in the house—he feels better able to protect | his family. Weare 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 first lesson to Icarn the famous Ia- waiianFolkSong**ALOHA”’’.Think g& how happy you will be when you (& the fascinating Hawaiian Guitar. Only Four Motions-- and You Master Them Quickly? ze emeemcenaamemmemwetes | $775 " cet estan GAL fo enscranarar + A pbadaacbe oe tay penn . 25 calibre—7 shot—C. O. Q. Automatic. Senuelied owalion Gaigun. maccemamy cian anechl ge my tt } 8.95 25 calibre—7 shot—Astra Automatic.

dod. wl

9.95 25calibre Astra with triple safety. 10.95 32 calibre—10 shot Astra, extra magazine, 16.95 32-20 and 38 cal. swing-out cyl. revolvers. We guarantee every gun against defective work- manship; brand new; of Drop Forged Steel Through- No Previous Musical Kr If you never read ical note é slightest knowle

“5 Lf

a in your life--if you haven’t even the dgeof music, we can quickly an positively teach you to pla this wonderfull, popular instrument, n’t be just a *‘listene er’’ when you can easily center of interest among your fricads. 40,000 successful students.

il a Post Ca Details Ai « out. Before buying any weapon INSIST on this - pontine FREE fp th ame guarantee. SEND NO MONEY unless. you fer--simply write: *‘I am interested’’-- F E wish. State model desired—pay postman on delivery but do it today. Satisfaction guaranteed plus Postage or money re | funded. Write for new firearms catalogue. CALIFORNIA TRADING CO. Terminal Bidg., First Hawalian Coupeeseten A Beautiful ae, Fe Hawaiian ‘ork City Guitar

Dept. 19, Los Angeles, Ca!

Page 116

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 1 Jewel Purlington ee Se NOW RAK ate + Adjusted to the Second Adjusted to Temperature Adjusted to Isochronism Adjusted to Positions 21 Ruby and Sapphire Jewels 25 Year Gold Strata Case Your choice of Dials (Including Montgomery Railroad Dial) New Ideas in Thin Cases ‘Down Only One Dollar Down will buy this masterpiece of watch manufacture. The balance you are allowed to pay in small, easy monthly payments. The Burlington — a 21-Jewel Watch — is sold to you at a price much lower than that of other high-grade watches. Besides, you have the selection of the finest thin model designs and latest styles in watch cases. Don’t delay! Write for the FREE Watch Book and our Special Offer today. Write While this Special Offer Lasts Get the Burlington Watch Book by sending this coupon. Find out about this great special offer which is being made for only a limited time. You will know a great deal more about watch buying when you read this book. You will be able to “‘steer clear’ of the over-priced watches which are no better. Remember, the Burlington is sent to you for only One Dollar down, balance in small monthly payments. Send the coupon for watch book and our special offer Today! Donot delay one minute! Burlington Watch Co., Dept. 13-66 19th St. and Marshall Blvd., Chicago, Illinois Canadian Address: 62 Albert St.,Winnipeg,Man. Please send me (without obligations and prepaid) your free book on watches with full exolanation of your $1 down offer on the Burlington Watch. Print name and address plainly Bookrack Has Compartments for Paper and Magazines ales a flat-top desk or a library table, the combination rack illustrated has the advantage that it holds not only books, but also magazines, note-paper and current correspondence. The original was made of walnut to match other furniture, but any wood may be used. The materials required are as follows: 1 pe. 34 by 10 by 2214 in. for the base 1 pce. 34 by 8 by 13 in. for the shelf 2 pe. 34 by 8 by 1014 in. for the uprights 4 pec. % by 2% by 4% in. for the pocket sides 2 pe. 4% by 234 by 7 in. for the pocket ends To simplify the assembly, screws are used wherever possible. The shelf is MAGAZINES By changing the shape of the end pieces many variations of this bookrack are possible being placed so close to the edge that the pocket ends will cover them, and the heads are countersunk. The uprights are screwed to the base. The pocket ends are nailed to the sides and the nails are set a trifle so that the holes may be filled with colored putty. The pockets then are fastened to the base and to the uprights with screws. The design may be varied in many ways without changing the construction. The top of the uprights may be rounded or given as decorative a profile as the maker wishes, and then the upper edges of the pocket ends may be modified to harmonize with them.—C. A. ROSELL: Handle for Holding Camera T IS difficult to hold hand cameras, especially those of small size, perfectly steady while a comparatively slow snap- shot is being taken. By adding the handle illustrated, however, the photographer can get a good grip on the camera with CAMERA (7 “aie | one hand only. ™! SSG A tripod screw, | NY Dp one end of which LR is a wood screw, is io = fitted into a file handle and a V — washer is fastened rp, CAMERA Lye, wesesospd «=6ON ~ the end of the BENTFROM ( sd = handle. If no such stata ia TS tripod screw is ws f y pee é f° — YACUP HOLDING av ailable, an or enporcasie Ginary woodscrew RELEASE can be cut down and one end threaded to fit the tapped tripod hole in the center of the camera baseboard. TRIPOD SCREW- HANDLE ~ This insures a good grip on the camera If a wire release is fitted to the shutter, | the finger end of the release can be held in a small clip bent from brass sheet and | held, as shown, between the camera and | the handle.—C. A. OLDROYD. screwed to the two uprights, the screws | Are You the Type Who Must Fe ar By Byram C. Kelly Science now knows that seven men out of ten mustfear aserious condition that \ comes atmiddle age. NB Hereisasituation that j you must face—a test that every man should make before it is too late. I am past 40 myself. I had begun to wonder when I would begin to break— to lose my old-time pep and aggressive- ness—when, through a mutual friend] made the personal acquaintance of certain member of the American Association for the Advancement of Science, whose wonderful work I had heard of. I made a trip to his labora- tories and the things I learned should interest every man approaching or past the prime of life. Surprising as it may seem, nearly two-thirds of all men past a certain middle age suffer with adis- order of the prostate gland. Common Middle Age Ailments Here is an important cause for many conditions which heretofore have been taken for granted a3 old-age ailments —sciatica, aches in back, legsand feet, frequent nightly risings, nervousness and irritability, and frequent dizzy spells, indicating high blood pressure. Constipation, headaches and depressed spirits often go along with it. But my visit would have been in vain had I not learned of an amazing treatment that relieves prostate trou- ble—a treatment that reaches this gland directly —and is so convenient that anyone can apply itin his own home. 10,000 Men Find Relief I know too plainly the effects of prostate gland disorder when it is allowed to continue unabated. I know of the operations and the common saying among many that theaverage life after this oper ation is only two or three years. That is whyl am doing everything possible to let people know of this importantdiscovery. Statesmen, bankers, law- yers, doctors, men from every walk in life have used the method with success. I have read hun- dreds of lettersfrom gratified men. One] remember in particular was froma Colorado man which says, “73 years young ismy age. Yet for years I suffered with prostate trouble. Used medicine to no avail —had about given up hope when a doctor recom- mended your treatment.” Just think of aman 7 years old restored to the health and buoyancy of youth—without drugs, electric rays or books. All Explained in Free Book If you have prostate trouble, if you suffer with any of the ailments mentioned above, you should not lose a day in finding out about this wonderful new method. Send immediately for an interest- ing, free book called,‘‘Why Many Men Are Old at 40.” It describes this splendid treatment and shows you how you may regain much of your youthful vigor. Send your request to the Electro Thermal Company, 0000 Main Street, Steuben ville, Ohio, the concern that is distributing these books for the author. There is no obligation. If you are not interested yourself, you may be able to do an “older” friend an immeasurable benefit by show- ing him this article. Mail the coupon. The Electro Thermal Company, 4037 Main Street, Steubenville, Ohio Please send me, free, without obligation, the booklet, “Why Many Men Are Old at 40. PERE oii cisseie baie au aeb oees crise nese ceeees eoee MORE isis. cps pas sano oles ennesauuseenbenssseseseees Address.......:. Salih Gee shun ssieseea enon eee eos ceot Western Office: Dept. 40-B, Los Angeles, California simpli quire’ and t on thi Th which inan pany! ing. mens cours varie the b those have satis! Th is th the ding lined or | ber | bott sides is @ | neat wall AVON -—_E

Page 117

ry man ce. eu to reak— ‘essive- riend] ce of a erican ent of labora- should or past it may 2n past 1 adis- ts ditions anted as legsand less and dicating ches and But my arned of ate trou- directly ply itin te gland nabated. n saying his oper- vhy lam know of ers, law- ife have oad hun- >member ich says, suffered no avail r recom- aman 73 yancy of oks. ‘ Ter with u should onderful interest- re Old at ent and of your _ Electro ben ville, se books you are to do an y show- ion, the soos cent $< ‘alifornia

guilt-In Ironing-Board Has Strength and Simplicity HE folding ironing-board and cup- poard illustrated is of very solid and simple construction. No braces are re- quired to support the end of the board and therefore there is nothing in the way on the under side. The method of building the cupboard, which may be installed in an old as well as ina new house, is made clear in the accom- panying draw- ing. The di- mensions, of course, may be varied to suit the builder, but those indicated havebeen found satisfactory. The cabinet is the depth of the wall stud- ding. It is lined with 34- or %-in. lum- ber on the top, bottom and sides; the back is a sheet of jneatly —_ fitted wallboard. The poort | | cupBoarD | YA! CATCHES Ai! | |

| MUCLEAT tat —= WinGUIDE CUPBOARD ' CATCH =HnHSTRIPS way? th alt ast DETAIL OF CLEAT Hn hf Ht ee) AHINGES 5 ae When open, the lower door supports the ironing-board casing around the cabinet matches the tm around the kitchen doors and win- dows. Two doors for the cabinet are provided. The top door is opened first. The board itself then is grasped and pulled upward until the end cleat reaches the stops on either side. Next, the lower door is swung out and the board is let down on it. A shelf is provided near the top of the cabinet for the iron and rest when they are not in use. When an electric iron is ‘used, the plug may be put in the wall of the cabinet.—HaRoLp J. BAKER, Port Huron, Mich.

Metal Edging for Woodwork ROUGH wooden edges sometimes can “ be finished cheaply and effectively with metal conduit molding, obtainable from electrical supply dealers. I used it recently when building a box for the back of a delivery auto.—O. A. es

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Living room, dining room, 2 bedrooms, kitchen, bath. 4 other plans, some with pan- tries, dining alcoves, grade and inside cellar entrances. Get free Aladdin Catalog. Here’s your opportunity to avoid high apartment rentals. Build this home yourself. Twomen can build it in a week. Our instruc- ce tions explain every step. Five ye) plans shown in Aladdin catalog. 117 You can buy all the materials for a complete home direct from the manufacturer and save four profits on the lumber, mill-work, hardware, labor. Price includes all lumber cut to fit; highest grade interior wood work, siding, flooring, windows, doors, nails, lath, roofng, with complete instructions and drawings. paid to your station. styles to choose from. Saving Aladdin Catalog No. 1067. glass, paints, hardware, Freight Permanent Homes—NOT PORTARLE. Many rite nearest mail today for FREE Money-

Large living room, kitchen, 3 bedrooms, large veranda— an ideal place for outdoor dining-room or sleeping quarters, Summer cottage price includes lumber cut-to-fit ready to nail in place, windows, doors, hardware, nails, roofing, paint, e Freight paid to your Station. Write today for Summer Cottage Booklet No. 1095. The ALADDIN CO. BAY CITY, MICHIGAN Wilmington, North Carolina; Portland, Ore.; Toronto, Ont.

ete With 110- Ex 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 POPULAR SCIENCE MONTHLY 250 Fourth Avenue New York

Send without delay for our free illustrated’ 64 page catalogue of Moving Picture Machines—Cameras—Stere- opticons — Optical Specialties — Finest Radio Sets—Complete Radio Parts We also sell best standard movie film and have a film exchange service for home users. Consult Us— Every Mail Box Our Branch Office PARAMOUNT MFG. COMPANY OF prt C BROADCASTING pw

Dept. PS-4 Boston, Mass.

AtLast!

workers—find out immediatelyhow port is embedded in flexible leather and does away with or stand for hours at a time with perfect foot comfort. D a St li } $2 A DAY EASY: men and women are making from $50 to 8150 a week seliiny thisnew foot pains, burning, tired feet, aches in calf and thigh that aimost every woman suffers with—so that even Low factory prices and high quality make every woman a customer. Write at once for free, sample case offer and Worn With Agents — salesmen — spare time kind of shoe. By a wonderful new method an arch sup- stout women can wear dainty ,sty lish shoes—dance, walk full details. No obligation. Address Roger Wilson, STYLE ARCH SHOE COMPANY Dept. 59 Cincinnati, Ohio

Heat, plenty of it, in base burner or heating stove. Clean, satisfactory, eco- nomical, convenient as steam heat. Brings happi- ness, plus.

Convert any cook stove, range or heater into a real gas stove. OXO-GAS, the cheapest, cleanest and mostefficient fuel known to science, is made rigiat in your own stove flame of high heating intensity as silently as city gas. Send for catalog illustrating and describing twenty different, distinctive designs of oil burners for Furnaces,Cook Stoves, Heating Stoves, Base Burners, Hot Water Heaters, etc. AGENTS Some choice territory for WANTED OXO-GAS agencies still open to thoroughly responsible parties. Yourown locality may yet be unassigned. GLORIA LIGHT COQ. Burr 103-9 North May Street, Chicago, Illinois

Mlustrating the OXO-GAS in cook stove, installed in a few minutes, lasts a lifetime, pays daily div- idends in saving health and happiness,

Page 118

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Buried in Mud and Water Years later, gun ts fished out and used A oun may be down, but it’s never out. At least that’s what John R.F. Workman, of Montana, thinks of the Iver Johnson. Read what he says: “I have one of your shot guns which I recovered from a deep hole in the bed of a lake, after being buried in mud and water for a number of years. This gun was in perfect shape with the exception of the mainspring, which broke while I was cleaning it. Inside, the barrel is as perfect as if made last week.”’ Iver Johnson Champion Single Barrel Shot Gun Barrel and lug of high carbon steel, forged in one piece. Barrel full choke which assures close, hard shooting. Adjustable mainspring tension bar; compensating locking bolt which auto- matically takes up wear; safety rebounding hammer; piano wire coil springs, heat treated, where necessary; real black walnut stock and trap style forend beautifully finished; genuine hard rubber butt plate. Various gauges and styles —including the Matted Top Rib and the .410. Send for Free Booklets Catalog ‘‘A”’ illustrates and describes Iver John- son Champion Single Barrel Shot Guns, Ham- merless Double Barrel Shot Gans and the famous Iver Johnson ‘Hammer the Ham- mer’’ Safety Revolvers. Catalog ‘‘B”’ describes Iver Johnson Bicycles for men, women, boys and girls; also Velocipedes for little children. IVER JOHNSON’S ARMS & CYCLE WORKS 5 River Street, Fitchburg, Mass. New York: Chicago: 151 Chambers St. 108 W. Lake St. San Francisco: 717 Market St. IVER JO! Your Tools and Their Care (Continued from page 77) take the temper out of as thin-edged a | tool as a chisel?”’ Here Old Prentiss picked up a piece | | broken from a very thin screwdriver. Striking a match, he put the tip of the | screwdriver in the flame. It was but a few seconds before the color began to run. “There, you see,’”’ said Old Prentiss, “we have a piece of soft steel—done with a match, too! You don’t require a forge to develop heat enough to draw the tem- per of atool. Now, if a match will do this, you can imagine what a grinder will do. Don’t take too heavy a cut or bear down too hard on the wheel, and dip your tool in water very frequently. ‘And here’s a hint about gouges. I saw Jim trying to sharpen a gouge on a straight-faced wheel. It can’t be done— at least, not by the average mechanic. There are wheels for the purpose, as well as emery sticks and stone slips for finish- ing up in place of the usual oilstone.”’ I thought the old fox had run out of opinions on the subject of grindstones, Hitting a hammer handle violently to draw a stubborn nail often snaps the wood in two oilstones, and sharp-edged tools, but just then his eye fell upon a hammer with a chipped face. He was off on a new line. “Now, what do you suppose does that?”’ | I guessed that it was probably a poor | hammer. Jim had the idea that it was the sign of old age. We were both wrong. “The fellow who put the handle in this | hammer didn’t know his job,” said Old Prentiss. ‘‘You see, the face of this head slants up instead of down. Now, when you swing such a hammer on the are of a circle, as you do when hammering any- thing, you hit high, with the result that some hard blow on such a thing as a cold | chisel, striking off center, will knock off the edge. “Several years ago I had the job of cutting the keyway in a 24-ft. flywheel. The key was 3 ft. long and 114 in. deep at the big end. It took me two days to do it but, although I chipped every bit of that metal out with hammers and cape chisels, I had neither mashed fingers nor a smashed hammer.’ Whereas, if the ham- mer had been hung like this one, I might have had both—and still be at the job! Now, if you have occasion to put a handle in a hammer, get it right. Don’t have the head at right angles to the handle, but SHOT GUNS have it turned down slightly at the face. ‘Then, too, use a hammer as one is sup- (Continued on page 119) Build Your Radio Set With Kellogg Guaranteed Parts | }+-PC 45588 =e S # Code 50) ELLOGG Inductance Switches are unique in de- sign and match the knobs of the Kellogg dial and rheostat. The switch arm is silver plated to in- sure minimum resistance. The arm mounts securely on the shaft, and a spring which is locked in place by two nuts, keeps the proper tension of the arm on the switch points at all times. Kellogg Switch Points are of brass with a heavy plating of silver. A low resistance contact is now available for radio work. The tinned terminal provides for easy soldering. ney are knurled below the head so that they will set securely in the panel. Kellogg Inductance Switch and Points improve the efficiency of your set. If your dealer does not handle Kel- logg, communicate direct with us. Kellogg Switchboard & Supply Company 1066 W. Adams - CHICAGO RDS 34 fil (Ni! on Gallon of Gasoline ‘ with Air Friction Carburetor We guarantee all other cars nearly doub fsEpresent mileage, power and flexibility (©) Z make hills on high formerly difficult 08 - tow. Models for any car, truck, sacks SESE Ge: marine or stationery engine. Makes cars better than new. Sce wonderful mileage Foe om a mi, § Oakind Dodge.....28ml, | Overi’d4.. .32mi, § Coled.... Wal If your car is not mentioned here send name and particulars and our ntee on it, AGENTS uy AL SENT ON 30 DAY’S FREE TRIAL You can drive any ear in heaviest traffic without 1 Starts off on high in any weather without priming or eating no jerking or choking, No more foul spark plugs To an 0 in cylinders, No leaking of gas into crank csee. PF shel days on our guarantee of money back if net entirety FUDGE No strings to our guarantee. YOU ARE . Anyone who can handle a wrench can oe &. ss . ew holes or changing of operating mechanism. todsy now holes UR -ERICTION CARBURETOR CO. |, « , 1208 Raymond Bidz, Dayton, Uhie, ; SEND FOR THE INTERNATIONAL CATALOG 5 Our net Prine of = ul buying Direct ractory ctory to FOR FORD-—Prices from $27.85 up. Factory consumer direct—Pay only One Profit soose, Il International Body Works, 914 W. Ohie St., Dept. §, Chicage, | tha car Wi dot

Page 119

eel "EST t With arts B+ cases 4 rs nearly doub! and flexibility, erly difficult os , truck, tractor, ine. Makes old age guarantees. 1 + 2 laxwl(25) 30m. ash 6.....23mb eres 0. Shaios US & _ CATALOG - net price list. Full line auto bodies and access Pe” hile #8) at bid a bodies oY ying Direct from HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY —— ae . . 6a your Tools and Their Care (Continued from page 118) posed to use it. The side of the eye was not meant to be used as the face, nor was , hammer meant to be used as a mallet ghen chiseling, nor the ordinary claw- hammer as a hatchet for ripping apart poxes, and things of that sort. You youldn’t expect to use a little bit of a dawhammer to pull a large spike. Get a nail-puller for that purpose; you will save | in the long run. . ; | “Only the other day I was speaking toa ‘manufacturer of hammers and he told me ee A wrench is turned as at the right, and not pulled backward, as at the left that one of his products came back from a carpenter who had used it for 17 years. While the quality of the hammer un- doubtedly had something to do with it, I am sure the most important thing was the | care the owner gave it. “Speaking of hammers,’”’ Prentiss went ‘on; “a monkey-wrench never was de- signed to take the place of one. It was meant to be used to turn nuts only. In | using a monkey-wrench, the jaws always |should face in the direction in which the wrench is to be turned. If the jaws face in the opposite direction, the tendency is for the jaws to spread. This puts an | additional strain upon the weakest part of Exaggerated for emphasis, this illustrates one of many ways in which wrenches are abused the wrench. Moreover, by using in this way, It may cause a slipping of the nut, and that damages both nut and wrench. It frequently happens that a nut is to € turned with an open-end wrench and that none can be found that fits exactly. have seen men try to drive the next smallest size wrench down on the nut with ahammer. This not only spreads the (Continued on page 120) TRADE MARKS COPYRIGHTS PROTECT YOUR IDEAS ANY NEW article, machine, design or improvement thereof, or any new conibination of parts or improvements in any known article which increases its efficiency or usefulness, may be patented, if it involves invention. If You Have Any New Ideas which you feel are useful, practical and novel, take promo>t action to protect your rights. If you have invented any new machine, or ncw 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. hana . : ; , DRAFTING and SPECIFICATION ROOM of CLARENCE A. O'BRIEN. Registered Patent Lawyer, Washingon, D. C. No Charge for Above Information All communications are held in strict confidence. thorough attention is given to each cace. 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 ani Trace 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-------- ee CLARENCE A. O’BRIEN, Registered Patent Lawyer, 886 Ss Washington, D. = td - ' HOW 1 - ecurity Savings and Com’! Bank Building, directly across street from U. S. Patent Office. TO Please send me your free booklets ‘‘How to Obtain a Patent”’ and OBTAIN “Invention and Industry” and blank form ‘‘ Record of Invention’’ j A without any obligation on my part. INVENTION = SAND oF INDUSTRY re -— ee “44 PATENT ” Important: **Write or print name clearly

Page 120

SINGLE ~HOLE MOUNTING

for these

within a condenser.”

SINGLE and of course,

eS et et Ne Dead

condensers. Plain Types Plate Vernier Plate Variable Plate Variable . Plate Variable Plate Variable . Plate Variable . + SUPERIOR CONDENSERS NEW Combination Types IW points of strength added to a still greater development of the exclusive Rathbun features that have won such wide recognition The vernier attachment is so utterly HOLE independent of the variable elements as to be practically a Neither shaft can contact fully insulated from rotor contact. .00002 mfd. affords the most critical tuning. Write for Literature TODAY 4é condenser the Vernier Vernier capacity of only Other points of these new move other. condensers are, the smallest amount of Bakelite for dielectric consistent with strength; positive contacts (no current through bearing) ; all metal parts of brass, bronze and aluminum assures minimum resistance; con- tacts from rotor and stator plates widely separated for high efficiency; MOUNTING. how good a RATHBUN Condenser is, until you've tried one. You'll never know just LIST PRICES: Combination Vernier Types -00002 $1.00 3-11 Vernier Variable... .$4.50 eee 2. 3-23 Vernier Variable.... 5.00 0003 $3.25 3-43 Vernier Variable.... 6.00 0005 $3.! 50 Combination Types Include Knob and Dial RATHBUN MANUFACTURING CO., INC. JAMESTOWN, NEW YORK HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

|| SbeMIXING of || {COLORS wePRINTS |

understand.

you benefit

AUTOMOBILE BOOKS Automobile Starting, Light- ing and Ignition, by Manly eatherette Hand-

$3.00

Automobile book leatherette 2.00 3rookes

SHOP PRACTICE BOOKS

FREDERICK J. DRAKE & CO. 1003 Michigan Avenue, Chicago, GENTLEMEN Please send me paid, your illustrated catalogue which describes over Home Study. o

chan een e ss ooo eS e+ ss | CD ee

Slide tree, 5 days ables lists DRAKE'S They Will Raise Your Pay! GET FREE CATALOG

PRACTICAL MECHANICAL

The books listed below will perfect you in your chosen trade—pave the way to the big positions. Written in non-technical language—eas sy to read and and Handbook | postage and 150 Practical Mechanical Books for | “for Modern Blacksmithing Cloth Machine Shop Practice ing si Modern Electrical Construc- ORDER DIRECT FROM THIS PAGE—ON Mail Coupon for FREE Catalog Your Guide to Home Study Every book covers its subject completely. An entire course of instruction condensed into one volume. -money Order direct from this page ON 5-DAY TRIAL. Rule I Your choice sent postpaid— refunded in full if not entirely satisfactory. Logarithmic Motion Picture Operation 1.50 Leatherette $2.00 Drake's Electrical Dictionary $1.50 Millw rights Electric Motors, D. & A 1.50 -Cloth 2.00 Electrical Measurements and AS Meter Testing _- 50 ‘ 1.50 Cloth 2.00 Drake's Telephone Hz undbook 1.50 Ss et as Mechanical Drawing and_Ma- Easy Electrical Expe ws nts at ee We Manty ‘pe 1.50 chine Design --Cloth 2 00 ~-.------- Cloth 1.25 St wes cia Lighting Pirin < Pattern Making _Cloth 1.50 Tele graphy Se 1f-T aug ght, Cloth 1.25 les, Remedies and Repairs, by Manly_.--Leatherette 3.00 ELECTRICAL BOOKS PAINTING BOOKS Automobile Battery, Care Telephony, Inc. Automatic { and Repair, by Manly - Switching, by Smith _ The Mixing of Colors and Leatherette 2.00 Leatherette $2.50 Paints oe .. $2.00 fires and Vulcanizing, by P ractical Applied Electricity 2.00 Scene Pi iinting and Bulletin lutford Cloth 2.00 Alternating Current 1.50 rt_ Cloth 4.00 Gas and Oil Engine Hand- 4 Electric Motor Control Sys- A Show at Sho’ Cards Cloth 4.00 book Cloth = 1.50 Te ae 50 Sign Painting Cloth 4.00 Automobile Upkeep and Care, - Wiring Diagrams and De- Strong’s Book of Designs by Manly Cloth 1.50 scriptions z | eee ee Leatherette 4.00 Motoreyck Handbook, | by a Electrical Tables and Data 1.50 Signist’s Alph: ibe ts Cloth 1.50 Manly Cloth 1.50 Armature and Magnet Wind- Modern Painter's C yelopedia 2.00 i 1.50 Automobile Painting Cloth 1.50 Estimates, Costs and Profits, Sheet Metal Workers’ Man- tion wt Painting and Decorating 1.50 ual_ Leatherette $2.00 Modern Electric Hlumination 1.50 New Hardwood Finishing, 1.50 Oxy-Acetvlene Welding and Electricians’ Operating anc The Amateur Artist___Cloth 1.55 Cutting. .....Leatherette 1.75 PRIME. cheek o nice oases Se 50 New Stencils......... Cloth 1.20 OUR MONEY-BACK PLAN The books listed above are only a few of the many in our catalogue, which you will receive promptly after filling out and m: tiling us the attached coupon. For quick action order direct from this page.—cross name of each book wanted and send in with price quoted. We prepay postage and send the books on our money-back plan. FREDERICK J. DRAKE & CO. PUBLISHERS 1003 Michigan Ave., Chicago Drake Books Are for Sale at ali Book Stores BOOKS

iii Your Tools and Their Care (Continued from page 119) jaws of the wrench, but it also ruins the | jaws on the end where the pounding js done, so that the entire wrench is dan. aged as a result. ‘Sometimes a mechanic will grind dowy the jaws of a wrench to fit a particula; nut; thereafter it will never fit any standard nut. In order to get more lever. age, he may resort to using a pipe for g lever, slipping it over the end of the wrench, or of hooking two open-end wrenches together so as to get the added leverage. A wrench is designed to with. stand a certain force applied at a certain particular point on the wrench in order to get torsion of a definite amount. As soon as the leverage is increased, the capacity | for producing this torsion is increased | whereas the wrench is still the same o'd wrench and cannot stand that much. If} the wrench happens to have hard metal in the jaws, the result is, of course, a brokey |

Pushing heavily on a wood bit necessary and often bends the shank is un- wrench. If the metal happens to be soft, then we have a spread that looks like a V. “Then there is another one of our much abused friends—the screwdriver. I have seen more than one man pry open a box or a crate with a screwdriver. You've prob- ably seen it done, too. First he tries to pry underneath the board and finding that it does not work, he takes a hammer and drives the screwdriver between the boards. Of course, the handle does not always break, and he may not have suc- ceeded in damaging the tool at the first blow. Then he sits upon it, or at least he presses down with his entire weight. There are few screwdrivers that will not

bend under these abuses, for the screw: | driver is a torsion instrument and is not to be used as a lever. “Even in using a screwdriver for the purpose for which it was made—to put In and take out screws—a number of abuses occur. When a screw is rusted so tightly in place that not enough torsion can be put upon the tool with the hand, a favor- ite stunt is to use a wrench or a pair : pliers. A screwdriver that will not fail under about 150 inch pounds cf torsion is a pretty good one. I assure you that it does not take very much pressure to ceed this, when you use a wrench or a pair of pliers. The result is, of course, 4 shank twisted beyond the elastic limit or a bent (Continued on page 121)

Page 121

seis Care UinsS the nding js 1S dam- nd down articular re lever. | ipe for a | of the »pen-end 1e added to with- a certain order to AS soon capacity creased same 01d | auch, If} metal in | a broken |

5 un- hank 0 be soft, likea V. our much I have 1 a box or *ve prob- p tries to ding that amer and een the does not vave suc- the first t least he weight. - will not

1e screw- nd is not r for the to put in of abuses :0 tightly n ean be , a favor- a pair of | not fail torsion is u that it ire to eX- or a pall , a shank or a bent <a,

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Your Tools and Their Care (Continued from page 120) blade, provided the screw head itself does not fail first. A few taps on the screw head often assist greatly in loosening a i the point of a screwdriver is too hard, even the best of care may not revent its snapping. Grind it up imme- diately, being careful, as in grinding cut- ting tools, not to draw the temper. Also, the screwdriver should have a relatively blunt point. It may seem rather ridicu- lous that I should mention it, but you yould be surprised if you knew the num- per of ‘cutting edged’ screwdrivers in use today. Grind the sides straight and parallel for about 1 in. and let them taper back after that. “If the handle becomes loose and is not ‘built into the tool,’ grind down the shank of the tool so that it has flat faces similar toa file shank. Then drive it into place and fill the crevices with hot rosin.” Prentiss now launched his last attack against the Gibraltar of our inexperience. “Take a saw—do you know how to care for one? I don’t mean sharpen it, for I’ll admit that is an art that can be mastered oly after many trials and even more i errors. I mean ordinary care. _— are many ways in which a saw can be damaged. One of these isto use too great a pressure in an effort to make it saw faster. Especially is this true in starting a cut, for pressure will cause the saw to move away from the line; then, in forcing the saw back on the line, you will cause a sort of kink in the blade and the chances are it will cross the line |tothe other side. In that way, it will zig- mg back and forth rather than cut straight. Allow the saw to do the cutting by its own weight until the blade is later- ally supported by the saw cut. Thereafter a little more pressure can be applied to cause the saw to work faster. “Keep a saw sharp by all means, for the tendency is to ride a dull saw more than a sharp one. It does not take a great deal of buckling to give a saw a permanent set; even though it may be slight, it will grow with use. “After completing a job, a coat of thin ! oil should be spread over the entire blade, because rust is a tireless and remorseless enemy of tools. I once loaned my pet saw toa neighbor. He returned it a week later, covered with rust. I questioned my wife and she informed me that the neigh- bor’s wife had used it to saw a ham bone. That explained it. The salt had eaten into the blade and even had attacked the teeth. No amount of emery cloth could restore the saw. It was done for. “There is only one rule for a mechanic ~buy good tools and treat them well! It is cheaper, your efforts turn out better, and you get much more pleasure out of your work.”

AMONG the Home Werkshop features Scheduled for early publication are: “How to Make Craftsman Dinner Gongs,” by J. T. Garver; ‘Stenciling aantwork with Sunlight,” by Ernest reg Ph D; “The Secrets of Success- ul Upholstery,”’ by William T. Weld, "sig “Automatic Fire-Alarm Signals,”’ y L. B. Robbins. —

ATENTS Coovaienrs NO CHARGE FOR 0 U & O ee F in a =» EXAMINATION AND 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 filustrated Guide BOOK 1—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 As our best advertisement, and will furnish to anyone, upon request, lists of clients in any state for whom we have secured patents. Highest References—Prompt Attention—Reasonable Terms

WRITE TODAY:

Free | VICTOR J. EVANS & CO. Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. oupon Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. Main Offices: 760 Ninth Street, Washington, D.C.

Gentlemen: Please send me FREE OF CHARGE your books as described above. POA ye ve tet hte tev say alee aera eis yc Address et PR gE

Page 122

> WurI HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Trade Mark 200 YEARS OF = C j OwnHome You may have any in- strument for a week’s | free trial in your own home. No obligation. No expense for trial. the coupon, Payments A few cents a day Instruments and will pay. complete outfits at factory prices direct to you, Sed for y New£atalo g i \ Ailustrated Se = : Send ; i=) oe . ) Z inQlors ¥ mn i

} b

The Rudolph Wurlitzer Co., Dept. 1786 117 E, 4th St., Cincinnati —329 So. Wabash Ave., Chica | 120 W.42ndSt., New York—250 StocktonSt., SseFranen’s Send me your new catalog, which illustrates and describes every known musical instrument, many of them shown in full colors, all at lowest factory Prices, Also tell me how I may have any instru- ment on a week's trial in my own h expense and without obligation it on your special easy payment (State instrument 1 ee eee Copyright 1 m whicr ,and may pay for plan, ome at your : Ou are canecially tnierested rer CO. — 122, The Paudotos Wurlitz

Farm Lighting Plant Furnishes Current for Radio Set By H. Leslie Curtis ‘T HERE is an interesting field of experi- ment open to those rural dwellers who possess the happy combination of a radio set and a farm electric plant. Under certain conditions the two may be com- bined in such a way as to eliminate the A-battery nuisance. My own radio set is supplied with fila- ment current from the electric plant and gives as good results as I ever attained through the use of a storage A battery, even when using a soft tube that is con- sidered very sensitive to changes in fila- ment current. The set, however, cannot be used while the generator is running. Therefore you canuse only adirect-current plant equipped with storage batteries. It would not be economical to use a plant of more than 32 volts. Any considerable change in the load on the lighting plant probably will necessitate a readjustment of the filament rheostat or the regeneration control. A motor running would be apt to cause un- pleasant noises in the head phones. Probably you also will find it necessary to use a hook-up in which the filament circuit has a metallic connection with

eee A \\\ Se A-battery troubles may be eliminated in farm-houses that have small electric plants the ground terminal of the set. By this I mean that there must be no condenser or other gap in series with the ground that would break the metallic connection between these points. Otherwise the counterpoise effect of the house wiring system, which is sure to be present, even it the wires are not accidentally grounded at some point, might weaken seriously the signals. The single-tube hook-up presented by Joseph Calcaterra in the January, 1924, issue of POPULAR SCIENCE MONTHLY ful- fils these conditions and gives excellent results when used in this way. With it I have heard KGO at Oakland, Calif., twice in three days. From central New Hamp- shire, where I live, to California is all that could be desired of one tube. Of course, this is by no means an every-day occur- rence. You must use some sort of resistance to reduce the voltage of the lighting sys- tem and protect the tube. I use a lamp bank, but a coil of resistance wire or a carbon-pile rheostat would be _ better. | The amount of resistance necessary de- (Continued on page 123)

IGEN ] DON'T LOSE YOUR # send for blank form ‘‘EVIDENCE OF Con. i will show youjust how to work up yourevi- Wa plication for patent. As registered patent at- 4m torneys we represent hundreds of inventors al] iM vancement of inventions. # of Conception,” sample, instructions relating A will co.

RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone CEPTION”’ to be signed and witnessed. 4 sample form together with printed instructions dence and establish thesame before filing ap- over the United States and_Canada inthead. Our schedule of fees willbe found reasonable. The form ‘Evidence to obtaining of patents and schedule of fees sent uponrequest. Ask for them,—a post card PATENTS ANO © -\TRADE MARKS 7

274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘‘Evidence of Conception.”

To the Man With an Idea I offer a most comprehensive, ex- |{- perienced, efficient service for his | prompt, legal protection and the | development of his proposition. ie Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladiy furnished with- Out charge. My experience and familiarity with various arts, frequently enable me to accurately advise clients as to prob- able patentability before they go to any expense, Booklet of valuable information and form for properly disclosing your idea, free on request. Write today. RICHARD B. OWEN ij Patent Lawyer l | Se sod 9 ch ARDS fe

ia 6 Owen Building, Washington,D.C, Rooms 809-810, 41 Park Row | Cortland 0721 New York City |

INVENTIONS < @mmercialized ON A CASH OR ROYALTY BASIS

/n Business 25 Years - Complete facilities References ADAM FISHER Mre.Co. 183-D StLovis,Mo.

PATENTS BOOKLET FREE 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.

| ’ Ay | that ' | side t few f rain t in the day until deep eve strike box, keep from that reach nien other js the is in road can |

Page 123

NCES SULTS

wyer C.

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

———— 2 Improved Movable Mailbox Designed by Letter-Carrier | A NEBRASKA letter-carrier designed | the movable mailbox illustrated so ‘that when a rut forms in the road along-

‘few feet away. Ordinarily after every rain the letter-carrier must drive his car inthe same track day after day until the rut 1s so deep that his car eventually strikes the mail- pox, or he has to keep so far away fom the box that he cannot reach it conve- niently. An- other advantage is that if the box isin the way of road graders, it can be set aside until the ma- | chine goes by. The mailbox has a | The cement heavy concrete base ‘hase is 16 in. ; square and 4 in. thick, cast in a form of four 1 by 4 in. boards held together with three hinges and a hasp and staple. The lower end of the pipe standard is split

with a hacksaw and spread out to form a | keyin the cement. The box is fastened to the split end of a shorter length of pipe, which is attached to the upright with an elbow.—DALE R. VAN HORN.

Wire Egg-Lifting Tongs by Sas eggs from boiling water is not difficult if wire tongs are at hand. Each end of a 28-in. piece of wire is bent | to form a loop about 1 in. in diameter.

The wire is then bent in the middle, two tums being made about a small stick to form a spring.—L. R. BUTCHER.

Farm Lighting Plant (Continued from page 122 /pends on the number and kind of tubes used, and on the voltage of the lighting plant. If you use a lamp bank, remember that the resistance of a lamp is much less when cold than when heated. Therefore arange a switch to short-circuit the tubes Until the lamp filaments are hot. Failure 0do this may mean a ruined tube. | Always use a test lamp of the same | Voltage as your tube in place of the tube when experimenting. Also keep an eye on the meter of the electric plant and see that no more current flows than is being used by the tubes. If one wire of the light- Ng system is grounded somewhere and you ground the other through the radio, ‘tough current may flow to waste to dis- | Charge the batteries or do other damage. ee

‘side the box, the stand can be moved a |

PATENTS Seventy-eight Years of Practice HE firm of Munn & Company filed its first application for a patent in 1846, and for seventy-eight years has endeavored to keep pace with the inventive genius of the United States. An experience of many years is at your disposal. If you have an invention which you wish to patent, send your sketches or model together with a description of your device, explaining its operation, and you will receive prompt, courteous attention. Write for our Handbook on PATENTS A full and complete booklet on Patents, Designs, Trade-Marks, Foreign Patents, Copyrights, Labels and Patent Office Practice with an explanation about our methods, terms, etc. All communications strictly confidential Keep in touch with theinventions of the world by reading SCIENTIFIC AMERICAN The MONTHLY MAGAZINE with a special appeal to every man of inventive genius. Recent rulings of the Patent Office, descriptions of the latest patented inventions, legislation and court decisions affecting patents, are noted in this authoritative publication, MUNN & COMPANY Patent Attorneys 683 Woolworth Building, New York City Scientific American Bldg., Washington, D. C. Tower Building, Chicago, III. Hobart Bldg., 582 Market St., San Francisco, Cal. Van Nuys Building, Los Angeles, Cal.

ECT NVENTO RS YOUR IDEAS Send for our Guide Book, HOW TO GET A PATENT, and Evidence of Invention Blank, sent Free on request. Tells our terms, methods, etc. Send model or sketch and description of your invention for our Examina- -—- - --------------—- -- 0+. --<-- tion and Instructions without ! Nite au. * ‘acim b STREET.........ccccecccccecce RANDOLPH & CO. : Dept. 130, Washington, D.C. ee STATE eee reser eeees

Page 124

WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY “We pay him $100 a week” ** aA ND he’s worth every cent of it. Came A here several years ago asking for a job. He got just that—a small job at a small salary. “Then I forgot about him—hardly knew he was on the payroll until one day I got a letter from the International Corre- spondence Schools telling me that he had enrolled for a course of home study. It was remarkable the way he went ahead. “We pay him $100 a week now and he’s gxoing to be earning even a larger salary some day. I wish we had more inen like him.” gt do you stand when your employer checks up his men for promotion? Does he think of you? i, there any reason why you should be selected? Ask yourself these questions fairly. You must face them if you expect advancement and more money. One hour after supper each night spent with the I. C. S. in your own. home will prepare you for the position you want in the work you like best. Yes, it will! Put it up to us to prove it. Without cost or obligation, just mark and mail this coupon. INTERNATIONAL CORRESPONDENCE. SCHOOLS Box 7613-D, Scranton, 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 _] Salesmanship (J Industrial Management [_} Advertising { |lersonnel Organization _] Better Letters (}) Traffic Management [|] Show Card Lettering { foe iness Law | Stenography and Typing Banking and Banking L am ] Business English Accountancy (including C.P.A.) (J Civil Service Nicholson Cost aarounine [] Railway Mail Clerk Bookkeeping _| Common School Subjects Private Secretary | High School Subjects _jSpanish O) French (J ilustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering O Architect Electric Lighting Fj Architects’ Blue Prints Mechanical Engineer Contractor and Builder -)Mechanical Draftsman Architectural Draftsman Machine Shop Practice a Concrete Builder [ }Railroad Positions -j Structural Enginee: “jGas Engine Operating r] Chemistry [J Pharmacy Civil Engineer Automobile Work Surveying and Mapping A Airplane Engine Metallurgy 0) Mining F Agriculture and P oultry Steam Engineering 0 Radio a Mathematics 3-6°24 RIES ODD consecccscrecsensvecssveconncocessscsubevcccsvesesbansesensestuecsveseseoses sous Occupation Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada Free Bulletin lists diamonds as low as $60 per carat, also Gems of Finest Qualfty at higher per carat charges but say prypesd @ Low Bargain Prices. This 1 3/16 car correctly cut cess ia snappy biesing sotftnine at $88. Th ear oldest largest Diamond Banking firm in Ralf the world lends money on diamonds. Thousands of unpaidloans; and other bargains. Many from big cash deals direct with European Diamond Cutters. Must sell NOW. Why Pay Full Prices Costs Nothing to men Any Diamond sent for absolutely free tion at our risk. No obligation. No cost to pba: Latest Listings — ye, Loans. Sent Fre Describes Diamond ——— ns_in_ Detail, aires: cash loan values guar: . Explains unlimited exchange privilege. Write ¢ to day for your co py of Diamond Bargain List. Postal card will jos. De Roy & Sons. 4724 De Roy Bide. ly Opposite Post O. Pittsburgh. P Traffic Policeman Signals the Suit that Is Trumps N ODD and convenient little in- dicator for reminding card-players of the suit that is trumps is shown in the accompanying illustration. A touch of a pencil will move the arm to indicate the proper trump. “No trump” is indicated by placing the arm in a vertical position. The base is 14 by 2 by 5 in. with a bevel running around the top edge. The signal tower is 3¢-in. material cut with a coping- saw. The figure is laid out on %-in. stock by means of squares. Each square in the = = pe eee” ba Front and side views of a novel home- made indicator for the card-table illustration represents 14 in. The figure is then cut out with a coping-saw. The arm is 4 in. thick and shaped as shown by the dotted lines. After the arm has been cut out, it is fa cened in the proper position rather tightly by a nail or screw. The tower and policeman are attached to the base by nails driven up through the bottom. An attractive color scheme is obtained as follows: Paint the base black and the bevel red. The figure should have a blue uniform with black trimming, and white gloves. Shoes, of course, should be black. The tower first is painted cream color; then the edges and base border are painted black. The club and spade designs should be black; and the diamonds and hearts red. The globe should be green with the cream showing in vertical streaks, as indi- cated.— KENNETH R. LAVoy. Pantry Rack for Knives ULL knives usually result when all are thrown together in a pantry knife-box. They are a source of annoy- ance to the hurried housewife and to the patient or impatient husband who tries to keep them in working condition. Better than a box is the double deck wall rack illustrated. The back piece is 14 in. thick, the first and second pan- els are 14 in. The knife slots either can be grooved in the panels or 14-by- V-in. strips can benailed or glued on back of the panels to form openings. In the latter case, all the panels can be 14-in. stock. Let the slots extend the full height to allow any material adhering to the blades to drop down. —DONALD D. SIMONDS, Worcester, Mass. How the rack is constructed No Money Down 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 w vatch 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 F actory. Page 12 of Our Watch Book Is of 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 exz amine. No Mone y Dow : Remember—No money down buys master timepiece—a 21 Jewel guz irantee ed tor a life a at about half the price you pay for a similar watch of other makes. No money down—a w cada rful offer, SANTA FE WATCH CO. 980 Thomas Bldg. Topeka, Kansas (Home of the Great Santa Fe Railway) = ee ee ee ee ee ee ee ee ee ee ee oe ee Santa Fe Watch Co., 980 Thomas Bldg., Topeka, Kan. Please send prepaid and without obligation your W: itch, Book free, explaining your ‘‘No Money Down" Offer on the Santa Fe Special Watch. Patent Litigation PATENTS Trade Marks aig on 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 McLachlen Bldg. WASHINGTON, D.C. po 20 derive larg: t profits know pon heed certain simple ot se facts before applying for Patents. Our book Patent- gives those facts; sent free. Write LACEY & LACEY, 643 © St., wasaingcon, vw. C., Estanitsued 28d9- PATENTS TRADE- MARKS, COPYRIGHTS AND PATENT LITIGATION lrite for «dvice ig instru s h t oceed, costs. etc | Hand nuk ack tees of 100 Me chanical j Movements sent fre a | ALBERT E. DIE TE RICH | | | | | | | Patent Lawyer and Solicitor Successor to Fred G. Dieterich: & C. m 681A Ouray Bidg. NG pour for | right Ana size | 141,2 cubi | -— ot mean oo Se o

Page 125

wn let us place pect, to ad- watch crea- d inspection nents of the other great a Life-time e Santa Fe 3-Springfield ok Is of ou t the Watch is Santa Fe and let us 1 the watch oney Down. nents buys a for a lifetime milar watch iderful offer, Co. ca, Kansas rilway) (_—_ eae gation your ‘No Money atch. at Litigation > Marks rights Protect In- awyer Corps \GTON, D.C. —————— ———— 10 derive larg: t profits know id omg certain mple but vita! k Patent-Sens? EY & LACEY, ed 21509. | oe SOAS ne T LITIGATION uc- Mechanical R 1CH | itor & Co. GTON, D. = Sky Sports of Tomorrow (Continued from page 27) The Vedette lifts, in all, a total of 2944 pounds, of which 794 pounds can be used for passengers and baggage. It is just right for a week-end cruise or a picnic. \nair yacht, so to speak. Some idea of its ze may be obtained from its capacity of 141,280 cubic feet, against 5,000,000 cubic feet, which is the figure for some of the large military dirigibles that have heen designed. Its length is but 190 feet; diameter 39 feet. Thus we have actually in existence an gir yacht capable of stowage in a garage of convenient size and fully able to mean- der down the bay on a holiday afternoon or to carry the owner and his sporting friends into the trackless wilderness after big game. Its speed of 50 miles an hour lends itself to sporting possibilities in the cass of amateur contests. OW let the two paths of air sport LN converge and see how bright the almost immediate future looks. From balloon jumping and swimming, athletes can evolve games analogous to football and baseball. Instead of ground rules we shall have sky rules. Bright-hued smoke | signals will lend color to the scene. Certainly there will be developed some form of paddle attached to the player’s hands or forearm to enable him to make appreciable speed. This suggests also that the form of a supporting balloon may be streamlined. And, further, that the | style of “air stroke’’ may be something | more zraceful and more effective than | | either the crawl or the trudgeon. | | An individual motor-propelled balloon | of this sort always has been a great medium for the cartoonist’s pen. As a matter of fact, it is very doubtful whether that convenience in vehicles is near at hand. Too many unhappy possibilities loom up when we think what motor trouble would mean. There is, however, a great opening along the line of a sort of “aerial surfboard.” Study of the prin- ciples of heavier-than-air gliders surely would lead to using those same vagrant air currents as leisurely agents for dirig- ible propulsion. Gliding and soaring already have come into their own abroad. But such engine- less contraptions always will be too dangerous for the general public. HESE new air sports with small balloons will be cheap. Quantity production will put them within the reach of every flivver owner. _ Helium always will be used because it ssosafe. Before the war this light and non-combustible gas cost $2500 a cubic foot. Now it is down to less than seven cents a cubic foot. So before long we won’t have to crane our necks to watch the big events of the sport world. In our air yachts we shall |be up in the sky where the games are staged. And even if we are on the ground We shall be able to see games played aloft | better than we now see games on earth ftom the grandstand. And when we feel the need of a bit of exercise we shall simply tap on our air preservers and loll in the Clear depths of the blue sky. ‘_—memumsmme and you keep this typewriter@ * ee UN Own ~= POPULAR SCIENCE MONTHLY in Fao on a DIRECT to you from our Factory Big Saving in Price Yes, we will you this Genuine Underwood Rebuilt in our own factory just like new for ONLY $3 down—NoT ONE CENT MORE Our Factory EVERY MACHINE is fully guar-a anteed. New parts wherever needed. New enamel, new nickel, new lettering, new platen, new key rings, new type—a complete, per- fect typewriter. Impossible to tell it from a brand-new Underwood either in appearance, durability or quality of finished work. An up-to-date machine with two- color ribbon, back spacer, stencil de- vice, automatic ribbon reverse, tabu- lator, etc. In addition we furnish FREE waterproof cover and special Touch Typewriter Instruction Book. You can learn to operate this Underwood in one day. Big Book FREE Our big, handsomely illustrated catalog will be sent free on request. It tells you all about the advantages of owning a STANDARD SIZE UNDERWOOD; how and why this machine will last for years, saving many dollars not only in the pur- chase price, but in its operation. Send in the coupon and let us send you this beautifully illustrated book FREE without any obligation whatever. SHIPMAN-WARD MFG. Co. Emporium” 7 STREET Montrose and Ravenswood Avenues, Chicago g CITY a 2146 Shipman Building Until you have tried Write Right Now and learn how it is possible for us to ship you this Underwood Type- writer upon our free trial plan and our direct-to-you money- saving methods. Get the full de- tails now—just sign the coupon and mail today. Get all the facts —then decide. No Obligation to buy. You don’t have to order. Just sign the cou- pon, send it to us and we will mail you our big catalog absolutely free. You will amazed at_ the liberality of our offer, the beauty and all around excellence of our type- writers, Coupon Today for * 10 Days’ Free Trial You have ten full days in which to try the typewriter before you decide whether you want to keep it. Give it every test—see for your- self—make the Underwood prove its worth to you. Do not take our word for it— FP; rwood TRIAL offer. put the Unde before 4 it is understood that Tam under no obligation oo ever and that this is to be sent without one cent think it the greatest type- 7% ct you and see if you don’t writer bargain ever offered., name the machine 10 full days at our expense This is the genuine Under. wood Typewriter. We offer you the same three models of the Underwood Typewriter being made and sold by the man- ufacturers today. Standard four- row single shift keyboard. Abso- lutely visible writing—the full line of typewriting is visible at all times. All the improvements and attache ments that any high grade type. writer ought to have. Big Saving to You Our plan of selling to you direct makes possible enor- mous savings, which are all for your benefit. Send in the coupon and we will send you prepaid our big catalog, including “A Trip Through Our Factory.” This shows how the Shipman-Ward Rebuilt Underwood is the best that can be produced at our Special Price, don’t have to doa thing to get our bi ou Free catalog pom complete details of our amazing typewriter offer except to sign and sendin FREE TRIAL SHIPMAN-WARD MFG. CO. 2146 Shipman Blidg., Chicago NEW catalog of UNL S and complete details of your Pleas d FREE, all ch: s fully prepai our BIG NEW all SND ER WOOD TEER: me. *“Typewriter STATE. Hunt with a BIASCUPE from afar. $5 and $7 at dealers. Money-back guarantee. Rochester, N Y. Six-power Pocket Binocular for all sportsmen, naturalists, etc. See game Direct, add 25¢. Circulars free. Wollensak Optical Company A sale antiseptic AbsorbineJ THE ANTISEPTIC LINIMENT If on your feet more or less all day—apply Absorbine, Jr. You almost see that hot, tired aching feeling disappear as the muscles relax their tension. A soothing, cooling sensa- tion comes quickly—and affords lasting relief. All druggists’, $1.25 or postpaid. Liberal trial bottle 10c. postpaid. W. F. YOUNG, INC. 350 Lyman St. Springfield,Mass. Cuts Strains Bruises Sunburn Insect Bites Pimples for

Page 126

POPULAR SCIENCE MONTHLY Heats 7 Rooms at about the Cost of One! “With the Bulldog Furnace, we find it takes little more coal to heat the whole seven room house than it did to heat one room with a stove using chestnut coal.” J. B. Smith, 19 Elm St., Somerville, N. J. More Heat with Half the Coal “I had a hot air furnace in our house before I got the Bulldog and our 7- room house was always cold. With the Bulldog it only takes half as much coal and we had weather below zero, and the house was nice and warm in the morning when we got up. We never have the draft on more thana half hour at a time, and it has the place red hot.” Jess T. Conrad, Sha- mokin, Pa. Comes Completely Erected! You Install It Yourself! If you are even thinking of a pipeless fur- nace, or any furnace, write for our free cata- log. The Bulldog is one furnace you MUST investigate. Comes completely erected, fits any height of basement, goes through any door, and you install it yourserlf! No Money Down? The Bulldog is sent you for free inspection. Then, if sat.sfied, you make only smail monthly payments, at our amazingly low price! Factory connections in both East and West. We ship from nearest point. Don’t consider buying any furnace until you find out about the Bulldog. Write at once for our special offer and our free catalog to- gether with the wonderful record of Bulldog success. Get ready for winter NOW! Mail this coupon TODAY! PTT TT Et Babson Bros. senceuces 19th & California Ave., Dept.13-66 Chicago Without obligating me in any way pl2ase send me your free catalog and special offer on the Bulldog Pipeless Furnace. Print name and address plainly. Name - RR otc ahem eh ebciheniabsicheshnainieesie - What Paint Means in Your Life (Continued from page 30) Mr. Gardner told me of researches that have given the industry special paints that dry with astonishing rapidity. “Tt is probable that new forms of the spray machine will work extraordinary changes in our whole painting scheme,” he resumed. ‘‘Today in some localities the consumer is asked an exorbitant rate for a painter with the hand brush. So nearly prohibitive is this cost that in country | districts farmers and house-owners gener- ally have let their buildings deteriorate. “AS USUALLY happens when a need shows itself, science came to the rescue with a portable spraying machine, mounted on a motor truck. It is said that some 300 community painting machines now operate in the country districts of the West, mostly on farm buildings. The rapid growth of this method seems certain. “‘T know this will not work disaster to painters. On the contrary, spray painting will enormously increase the use of paints and, correspondingly, the field of the painter—just as the sewing-machine en- larged the demand for factory garments. “‘Experiments show that one of these portable spray machines operated by one man upon large areas of unbroken sur- faces will do the work of four or five painters, although the paint consumed is about one-tenth more than that used by the hand brush. There is practically no difference in the appearance of the work.”’ Experiments to discover the effect of paint colors on temperature, health, growth, sound, and light have produced | interesting results. ‘Tests were made to ascertain what effect the color of a steam radiator might | have on its heating capacity,’”’ Mr. Gard- ner told me, ‘‘and a difference of 20 per cent was found between white painted and unpainted iron radiators; the white giving the greatest radiation. Between these two, the following colors, in the order given, showed more or less difference in radiation: Cream, red, green, yellow, black, aluminum and brown. “© TMILAR experiments were made with colored paints on small metal tanks of naphtha. Temperature readings were taken after exposure of the tanks for two hours to the sunshine. Those painted black showed the highest. Next in order came bright red, dark red, dark green, battleship gray, tan, cream, pale blue, and white. There was a total difference | of 11 degrees in favor of the white. This | meant that the darker colors caused greater loss of naphtha through volatili- zation. With black, the loss was nine per cent; with white, only four per cent. ‘Work on aluminum paints has indi- eated their value in cutting down the ultra-violet rays of light. Appli- | eation of the principle was made in coat- ing the surfaces of balloons and airplane wings to prevent the rotting of the cloth fabric and to minimize the temperature effects upon the gas cells. “Research in connection with paint vapors demonstrated the disinfectant quality of paint. Vapors of the drying oil in paint were found to contain formal- dehyde, and therefore it is used jn hos. pitals and homes in place of chemical gic infectants. “Another series of tests had referenc to the effect of paint colors on humay growth. Rabbits were placed jn large boxes, painted in different colors. It ap- peared that light colors of high reflectioy value were most favorable to rapid growth, while colors of low luminosity exerted a retarding influence. ‘ “The effect of colors on the growth plant life also has been tested. belladonna seedlings were placed under porous paper cones of sufficient height and width to prevent interference with growth. The interiors of the cones were painted white, red, orange, yellow, green, black, and purple-tone blue. In three days evidence of plant fatigue became apparent under the blue. The leaves bleached to light yellow, and one broke from the stem. Under the green there was some yellowing, though the plants were in good physical condition. Each color had some effect. Application might be made in the coloring of special plant breeding boxes. of “TNVESTIGATION of the effect of paint on sound yielded unexpected re- sults. In a certain church acoustics were very bad; echoes were everywhere. After several coats of a stippled paint had been applied to the walls, there was material improvement. “In another case, diners at a certain country club were annoyed by the babel of voices. Ceiling and walls were given two additional heavily stippled coats of paint, and the change was marked. Again, when the walls and ceiling of an auditorium were changed from smooth plaster to a rough finish, reverberations were much reduced. ““A test was made to discover what dif- ference there might be in the effect of wall finishes on sound. With a plain metal wall, sound carries 40 inches; when the metal wall was coated with a sand finish, 19 inches; with a sponge-finish paint, 18 inches, and with paint in cork finish, 14 inches. “—_ possibility of having walls so painted that they yield by reflection 85 per cent of normal light is important. Experiments showed that inacertain room painted with ordinary white, four 100- watt lamps were necessary for illumina- tion. Through the application of non-yellowing paint only three 100- watt lamps were required. Paint sub- stances have been found that stay white and keep their reflection value. The difference between well-painted white ceilings and ordinary light buff, for in- stance, may increase illumination from 20 to 30 per cent where semi-direct 0° similar lighting systems are used. “Studies are now under way to pre vent the fouling of vessels. Thousands 0! chemical and biological experiments have laid bare the habits of marine animals. Barnacles live only in the harbors—they do not venture beyond the ‘three-mile limit’ except as passengers on ship hulls. (Continued on page 127) a Potted | ~ «+ &. Od

Page 127

i d in hos. Mical dis. reference n human in large s. It ap- reflection to rapid iminosity Zrowth of Potted ed under nt height nce with Ones were Ww, green, hree days apparent’ eached to the stem, yellowing, 1 physical me effect, e coloring effect of pected re- stics were re. After had been 3 material a certain 1e babel of given two coats of marked, ling of an n smooth rberations what dif- ect of wall ain metal when the and finish, paint, 18 finish, 14 ry walls so r reflection mportant. ‘tain room four 100- - jlumina- jon of a ree 100- aint sub- tay white ue. The ed white ff, for in- tion from -direct oF d. y to pre yusands of ents have » animals. ors—they three-mile ship hulls. ) ee What Paint Means to You (Continued from page 126) “In these experiments thousands of etal panels were coated with paints of jifferent formulas and submerged in har- yors for varying periods. The formulas showing the least fouling were retained for further experiment, and through this process have been evolved paints that ‘lve the problem to a great extent. «This study told us many things. The young organisms reacted to various stim- yi-such as light, color, and chemical aibstances—in different ways. In some experiments with anti-fouling paints the parnacles reacted negatively. Again, they were so injured that they lost the power of reproduction or died and dropped off. “(\NE experiment was made with a deadly chemical substance devel- oped during the war. Through some curious contradiction of nature, bar- nacles waxed fat on paint containing this acid. Something like 300 different poisons have been tried in our tests. Dark hues ysually revealed a tremendous fouling of the metal with barnacles and other sea creatures, while colors of high luminosity showed comparatively little. “A study of color preference of the lower forms of animals also has yielded information of practical value. Certain species of crustaceans showed a marked preference for colors of low luminosity. “Other fruitful experiments have been made in the development of protective coatings for wooden underwater struc- tures. One of the most destructive creatures of American harbors is the toredo—an animal that delights in honey- combing a wharf foundation. “Fire-retardent paints,” Mr. Gardner told me, ‘‘have been evolved through re- peated tests.”” A full recital of paint achievements would include almost a catalogue of paints and varnishes—for innumerable specific uses. You hardly can find any sur- face for which a paint or varnish has not been specially devised. IFFERENT woods and metals call for different technique in painting, and perhaps require special paints. Or different conditions in the same wood may indicate some particular treat- ment. In paint and varnish terminology you find such expressions as chalking, peeling, scaling, flaking, alligatoring, livering, and fouring. For all these and many other ailments cures have been sought with chemistry and kindred sciences. New uses and new paints are constantly com- Ing out of the crucible. HIS is the first of a series of articles - by Mr. Woolley on what science is doing for industry. Every move science makes, every betterment it brings about in industry, has a definite bear- ingon your welfare. In this fascinating Series Mr. Woolley will point out, one by one, the steps that science has taken n your interest. In his next article he will relate how science has taken hold ot the automobile industry to make Your car safer, more efficient, and Comfortable for you. Se POPULAR SCIENCE MONTHLY 127 Waist Reduced in 10 Seconds ~With New. Self-Massaging Belt / Stop dieting and starving yourself—stop tire- some, monotonous, fatiguing exercise—stop pay- By means of a wonderful new scientific, self-massaging belt you can make your waist thinner AT ONCE. Send coupon below for full particulars. ing money to expensive masseurs. protruding abdomen. ji ie need now for any man to carry around a large, success and happiness. Through a wonderful new invention, thousands of men have found the one safe, easy and pleasant way to get rid of the excess flesh around their waist. don’t need to starve themselves or go on a diet of any kind—they don’t have to take strenuous, heart-strain- ing exercise—and they don’t have to pay the exorbitant Yet they fees charged by a professional masseur. daily get thinner and thinner—they look years younger—and they actually im- Not only does it mar your appearance—not only does it make you look years older than you really are—but it actually impairs your health, and thus ruins your chance for They prove in health too! The Secret Explained This amazing new discovery is a re- markable new kind of a belt, which ac- tually takes off fat in an easy, gentle way. Yet results are remarkably rapid! The moment you put on this new self-mas- saging belt you feel like a new person! Your waist is instantly reduced about 4 to 6 inches—your chest expands—your head and shoulders go back—your carriage becomes firmly erect. And what is even of greater importance, after a few weeks results become permanent! The Weil Scientific Reducing Belt, as the new invention is called, is the result of years of careful experimentation and research by experts. It is made of specially prepared and scientifically fitted rubber, and is so constructed that it provides a constant gentle massage to the abdomen. Every time you move—every time you even breathe—a certain amount of fat is mas- saged away, and before you know it your girth becomes inches smaller! In many cases reductions of as much as 8 inches have been noted within a few weeks! And with this rapid reduction of the waist a wonderful improvement in health is im- mediately noted. Stomach disorders—back- ache—constipation—shortness of breath— all vanish, as the sagging internal organs are once more brought back to their normal positions. @ REGISTERED PATENT ATTORNEY SINCE 1905 CHARLES W LOVETT Sut 8100 1y¥N MASS. * : Hf SEND FOR FREE BOOKLET Bae Finest bicycle built—44styles,colors and sizes. Factory to Rider prices. FREE delivery, express paid on 3 days free trial.Cash oreasy paym’ts. 3 . « lamps, wheel: d i t ire$ at half veual “prices.” Send no del Wehere etn aa. Se marvelous offers. Bicycles, $21.50 up. Wie SOP sacaeaen Wz Ve = fod 10 DAYS’ TRIAL SEND NO MONEY We don’t want a single penny unless the Weil Scientific Belt convinces you that it will quickly and easily help you to reduce your waist just as it has thousands of others. So we are willing to let you try the belt for 10 davs at our risk. simply send the coupon below and full particulars will come by return mail. If you write at once, you can also get in on our new Special Reduced Price Offer being made for a limited time. Mail coupon TODAY to The Weil Company, 109 Hill Street, New Haven, Conn. The Weil Company 109 Hill Street, New Haven, Conn. Gentlemen: Please send me, without obligation, com- plete description of the Weil Scientific Reducing Belt and also your Special 10-day Reduced Price Offer. WAM an cdossasusawenns \ddres The Johnson Folding Pocket Rule Tho Johnson Folding Pocket Rule is made of Spring Nickel Silver, accurately and distinctly graduated. It can be used a» a Square, Hook-ruie, Caliper gauge, Protractor, Triangle, or Tri-square, and can be applied 1o practically all classes of mechanical work. ernier 1 ead~ to one- half degree. Center Joint has hbre bear- ings which will not become loose and wiil remain firmly at any angle. No. 46—6’’ Rule $2 5; No, 45—12' ) $3 50. Including chamois cases. Money refunded if not satisfied. Catalogue on r+ quest. E. P. JOHNSON RULE MFG. CO. 565 W. Washington blvd., Chicago, Ill. _-For You--Mr. Sign Painter It’s the very newest and Jat- 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- Se half the usual time. Make - Sign Painting and Show- card Writing as easy as A, B, C. Samples for stamp. JOHN F. RAHN, D-2433 GREENVIEW AVENUE, CHICAGO, ILL.

Page 128

128 POPULAR SCIENCE MONTHLY How to judge tobacco The true test lies inside the pipe—not in the pedigree, says Mr. Krob In the following letter Mr. Krob points out that once we are past the infantile stage of “taking the watch apart to see what makes it run,” we learn that true happiness is a matter of appreciation rather than of analysis. How do you feel about it? Lorain, Ohio Larus & Brother Company, Richmond, Va. Gentlemen: Most people who are buying Better Light look up at the fixtures we install and say, ‘“‘That’s wonderful,’’” when they should not even be interested in the fix- tures. They should look down at their desk-top or counter or work-bench, where they actually use the light. They always want to consider it “‘F.O.B.” the lighting fixture, instead of ‘“‘Delivered’’ to the working plane, where it is to be utilized. Personally, that’s the way I look at tobacco. Many manufacturers go into de- tail telling us where their product is raised, how it is blended, how long it is aged and how well it is packed, and place this infor- mation before the public in their adver- tisements Why should we care whether tobacco is raised in the Sahara or on an iceberg, whether it is a blend of ‘'57 Varieties’’ or run-of-the-mine, or whether it comes packed in cork or cast-iron containers? I buy my tobacco because of the way it tastes in the pipe. That’s why I use Edgeworth. Sincerely yours, K. M. Krob. As the producers of Edgeworth we are of course vitally inter- ested in its pedigree. We are absorbed in the blend of Ec ge- worth and in its cur- ing — in every detail of its de- velopment. But all our work and ex- periment and study has but one object—that Edgeworth may prove its worth ‘‘Deliv- ered—Pipe.”’ And that’s all we expect you to be interested in. Let us send you free samples of Edge- worth so that you may put it to the one and only test that counts. If you like it, so much the better for us both. If you don’t—well, that’s that! Write your name and address to Larus & Brother Company, 59 South 21st Street, Richmond, Va. 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 Edgeworth Plug Slice or Ready-Rubbed for the same. price you would pay the jobber. Wonders of the Sea (Continued from page 37) the United States, the Middle Atlantic coast, further removed from the influence of the Gulf Stream, knows variable tem- peratures and cold winters. An equally remarkable phenomenon is the Sargasso Sea in the center of the North Atlantic. This is an area of still water several hundred thousand square miles in extent, filled with a seaweed called sargassum, known also as the gulf weed. This weed is believed to grow on the distant shores and to be carried to the Sargasso Sea by ocean rivers such as the Gulf Stream. other similar, though smaller, bodies of still water in the Pacific and Indian oceans. This probably will suffice to give a superficial picture of the physical char- acteristics of the sea. The real wonders of the sea are far beneath its depths, for the sea contains much more life, both animal and vegetable, than is present elsewhere on the globe. These specimens of marine dwellers are of exotic forms and colorings and of weird physical characteristics such as are possessed by no animal or plant of the land and no bird of the air. TRANGELY enough, though, the queer denizens of the deep are be- lieved by scientists to possess a kinship with the animals of the land, even includ- ing man. Chemical analysis of sea water shows that in the salts it contains it is remarkably similar in composition to human blood. From this fact the theory has been advanced that all life had its origin in the sea; that the salt water which the early sea dwellers carried in their bodies when they took to the land has been passed along as blood from gen- eration to generation through all the evolutionary changes that have taken place to produce the higher forms of life. This, however—assuming that the theory is correct—is about the only relic | that man and the other animals of the land have taken from the sea, for none of them has the physical capability of sup- porting life beneath the surface of the ocean. It is not so much a matter of ob- taining air to breathe, for science might supply the means of obtaining that. Divers have descended 200 feet and more into the sea. That they cannot descend further is due to the enormous pressure of the water, caused by its weight. If you have ever tried to “fetch bottom’? when diving into a lake or river, you undoubt- edly have experienced the effect of that pressure in a slight degree. Your ears haverung; there has seemed to be a crush- ing weight pressing on your head and chest. I OW, the painful, crushing pressure that would be felt 20 feet or so be- neath the surface of a shallow inland stream of course is multiplied immensely at the bottom of the sea. Science has cal- culated the average pressure at the ocean basin to be about 214 tons to the square inch. In the deeps it is five tons or more to the inch. The effect of that enormous pressure has been demonstrated by many (Continued on page 129) There are at least four | FREE/°&, Book for Red bloods Ls E a man or a mouse. Forge ahead } B world or slink into your hole fike a timid aoe beastie. Choose between success and re mo happiness or misery. Nobody else can choose for you. **Do It With Muscle!’’ my newest book, js Ps helpful, plainly worded true story of how I became the Physically Perfect Man and attained world- wide professional eminence, prosperity and family happiness; how thousands of my pupils have achieved shining lives through the conquest of constipation, world-weariness, fear, debility and the whole ugly horde of physical, mental and ‘sextial disorders resulting from ignorance, neglect and folly Lavishly illustrated with scores of superb camera studies of myself and pupils. Be fair with your best pal... that’s You. Get your complimentary copy of ‘*‘Do It With Mus. cle!’? Then Do it! No obligation and no charge for the book. Just send the coupon right away with one dime (10c) to help defray my mailing costs, LIONEL STRONGFORT Physical and Health Specialist for 25 Years Dept. 1480 Newark, N. J., U.S.A. f-—— —-FREE BOOK COUPON- = ==«e5 ! LIONEL STRONGFORT, y ' Dept. 1480, Newark, N. J., U. S. A. i] | Send me my complimentary copy of ‘*Do It With ! Muscle!’ for which I enclose one dime (10c) to ! 1 help defray mailing costs, assuming no obligation. I i This book may mean the making of a better Me. 1 i MIMMC pcckscce ena eeeeneen eas hase nekenccoecemes : i ' SSC RINGERS! poet ee bo ee ee ! , 1 ne ee eee ne a ee State a SS aeons PICK UP THIS EASY SPARE TIME MONEY And Get Your Own Shirts FREE Here is an amazing easy way for you to make $5 to $10 every evening after work. Our wonderful new shirt line contains the most attractive styles in silk, linen, madras, etc., and can be sold 50% cheaper than store prices. We will furnish you a free sample line and tell you exactly what to do to make big money this way. We tell you exactly what to say. You receive your profits in advance—we dee liver and collect. Write at onceforfree territory offer. No obligation. But act quick. Address Charles Hope, FASHION WEAR SHIRT co. 1200-20 Jackson St., Dept. 79 Cincinnati, Ohio interest gceanog If yo cork it, into the think W you pul ork dr the bott | repeat t | hall, thi | of the sé | throug | the gla that it face agi remove sure W' cavities become t- se in clot | der, Wi | ine an drawn almost hamm | tube W | | Any j ocean, | sure is | terial way | bursti which of the below would other | stitut | sure, | swim | expar | organ Th deep- | t0 th | inhak | ough | press M

Page 129

1 in the nid little | failure, ‘for you, ok, igs a became 1 world. 1 family ls have \uest of ity and d sexual nd folly, camera ou. Get nh Mus. ) charge fay with osts. rs J. S.A —aag With ’ Oc) to! r you after line >s in n be ices. Jine nake you ve des ritory dress “CO. , Ohio Wonders of the Sea (Continued from page 128) nteresting experiments performed by ncegnographers. If you were to take an empty bottle, ork it, affix a weight to it and let it down ato the sea depths on a line, what do you ‘;ink would happen to the bottle? When vol pulled it up again, you would find the ‘work driven in by the ocean pressure and ‘the bottle filled with water. If you were to repeat the experiment with a hollow glass ‘hall, this would be crushed, or the pressure ofthe sea would force water into the globe |irough imperceptible imperfections in ‘the glass. A block of wood, weighted so that it would sink, then drawn to the sur- ‘ae again, would no longer float after you removed the weight, for the ocean pres- wre would have forced water into the wyities of the wood, causing the block to pecome thoroughly water-logged. NCE on an oceanographic voyage, a scientist wrapped a sealed glass tube in cloth, placed it within a copper cylin- ‘der, weighted the apparatus, attached a \jineand threw it overboard. When it was drawn up again, the cylinder was crushed ‘almost flat, as though pounded with a hammer, and all that was left of the glass |tube was a small quantity of powder! | Any watertight vessel thrown into the | ocean, reaching a depth where the pres- | sure is too great to be resisted by the ma- ‘terial of which it is composed will give way by what is called “implosion,” a bursting inward, the opposite of explosion, which is a bursting outward. Even a fish of the upper strata of the sea, descending below its accustomed pressure level, would be killed by implosion. On the other hand, a fish from the bottom, con- |stituted to live in a region of great pres- jsure, actually would explode, if it should |svim too close to the surface, due to the expansion of the gases in its internal organs from the reduced pressure. That there can be animal life in the deep-sea areas of enormous pressure is due |tothe fact that the bodies oi the creatures |inhabiting them are porous and so thor- loughly filled with water that the great | pressure is not felt. \fANY of the deep-sea animals re- ‘"’ semble plants in their structure; tey are exquisitely formed, and deli- ately colored. Their bodies consist of ‘im, graceful ‘“‘stems’’ surmounted by onjects that seem to be full-blooming lowers. But these forms of life are not pants, but animals; for there is no vege- tation at all in the depths of the sea. _ Then there are crustaceans and spider- ike Creatures innumerable, and amazing ish that seem to consist mostly of eyes and mouths. All of these creatures may % said to live solely by eating one an- other, for the quantity of food that falls to them from above in the form of carcasses * Upper-sea animals is small. This ex- Plains the huge mouths and sharp teeth of gg deep-sea fishes: few opportunities to eed Come to them, so they must get all ‘he food possible when chance presents. oe has further aided them in “ig the problem of existence by pro- (Continued on page 130) = scala ee ene POPULAR SCIENCE MONTHLY 129 The Federal “Fifty-Nine” is the one radio set . . . mea , that receives the enthusiastic endorsement Ne g4 of fans and families alike. Three simply operated controls give you all the thrills of selectivity and distance range, ‘ while additional dials offer the finer shades \ of tone refinement. Priced at $177 With headphones Boston For loop reception (No. 61) $4 6 Extra Look for this sizn Bitarse:te * RADIO Write us for name of your nearest Federal Dealer FEDERAL TELEPHONE & TELEGRAPH CO. BUFFALO,N. Y. New York Philadelphia Chicago Pittsburgh Bridgeburg, Canada © everal Sander RA DQ Protos San Francisco (12 CELLS—24 VOLTS) lions of prospective buyers—this WORLD Storage ‘‘B’’ anve. Hereisa battery th-+ pays for itself And you save $2.00 by ordering now. It holds its charwe, while idle, at constant veltage It does away with a great many noises so often blamed **static.’’ Mail your order today. SEND NO MONEY volts), $15.00. Pa and save $2.00. WORLD BATTERY COMPANY SPECIAL INTRODUCTORY PRICE For a limited time only, and to introduce this new and sup?rior Storage ‘‘B’’ Radio Battery to the Public, we are selling it for $4.00. Regular Retail Price is $6.00. You save $2.00 by ordering NOW. We believe there is no better battery than the World Storage “B” Battery To ten million homes with Radio Sets—and to countless mil- Bat- tery brings a new cor.ception of battery economy and perform- . in a few week will last for years and can be recharged at a negligible cost. e Equipped With A Superior Battery sclia Rabber Case Has heavy duty 21-8in. x lin. x 1-4 In. plates and plenty of acid circulation. Extra heavy glass jars allow ready observa- tion of charge and prevei t leakage and seepage of current. You will find this battery a boon to long distance reception on Without cost or obligation, Just state number of batteries wanted and we will ship day order is received. EXTRA OFFER: 4 batteries in series (96 Expressman after examining batteries. 5 pen cent discount for cash in full with order. Send your or Makers of the famous World Radio **A’’ Storage Battery 1219 S. Wabash Ave., Dept. 89, Chicago, Ill. SAVE $2.00 CY ORDERING NOW! | | | U. S. Government Needs Men! ONDERFUL opportunities in CIVIL SERVICE. Thousands of men and women appointed every year as Income Tax Auditors, Bookkeepers, Railway Mail Clerks, Postmen, Deputy Coiiectors, etc. Generous saiaries, short hours, liberal vacations. Positions open in Washington and in every other city of the country as well as in Porto Rico, Alaska, Hawaii and the Philippines. Write for 48-page FREE BOOKLET on CIVIL SERVICE, which tells you how you can get a good-paying position with the U. S. Government. Mail the Coupon To-day INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7615-D, Scranton, Venna, please send me a copy of your 48-page CIVIL SERVICE BOOKLET, which tells how I can secure a position with the U. 8. Government. ier PRD ccacesnnsavnncccsdesastins sesanesearentiineian | Street | | i OUTRODUE ssiscscsucccxcsicatonsstvssaucenncwsas sdvseteonacessvedsseseseeeeea | 1 >) See state

Page 130

130 - é ga ie ae P EARLE E. LIEDERMAN The Muscle Builder lf You Had a Face Likea Monkey you would try to change it. But just because you wear a pair of pants and a coat to cover the rest of your body you don't seem to care a rap what you look like from the neck down. Come on out of it fellows. Get wise. Don’t you know you can’t keep this up? It’s only a few years and ZOWIE it’s too late. Your body is clogging up with all kinds of poisons. The only way to get rid of these poisons is to drive them out. Exercise wears off the worthless tissue, the blood carries it to the surface and then you sweat it out through your pores. That’s simple enourh. Dut it you don’t — your blood will absorb all this poison and soon wou're nothing but a human wreck, f I MAKE STRONG MEN No one likes to look at a narrow-shouldered, flat- chested dyspeptic. Such a man is no good to himself or anyone else. It’s the strong, robust, energetic man v ho gets ahead. He is admired and sought after in both the business and social world. No matter where you find such a man, he is the whole works, Come on then—snap into it. Richt now—this minute. This is your day. This message v-as meant for you or you wouldn't be reading it. I’m all set and waiting for you, and oh boy! what I do to you will sure open your eyes. I'm going to push out that chest of yours, broaden your shoulders, and put a pair of arms on you that wi!l carry the kick of a mule. I'm going to bui!d up your whole body with good, solid muscle. I'm going to strengthen every vital organ and shoot a quiver up your old spine that will make you feel like a jack rabbit. — CAN DO IT Just because a man is built like an ox doesn't mean he can show you how to be the same way. There are plenty of strong men today who couldn't tell you how they ever did it. I made my reputation teaching and building others. And my biggest achievements have been made during the past year— not ten years ago. My instructions are modern and up-to-date. When you come to me your success is assured. I don’t promise strength—I guarantee it. Are you ready? Let’s go. Send for my new 64-page book “MUSCULAR DEVELOPMENT’”’ IT IS FREE It will show you what I have done for others and what I guarantee to do for you. It contains forty- three full page photographs of myself and some of my many prize-winning pupils I have trained. Some of these came to me as pitiful weaklings, imploring me to help them. Just look at them now and you will marvel at their splendid physiques. This book will prove an impetus and a real inspiration to you. It will thrill you through and through. 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 if off. Send today—right now before you turn this page. EARLE E. LIEDERMAN Dept. 1309, 305 Broadway, New York City SE FERN Sk Se A A TUS CS SS CME eras ame EARLE E. LEEDERMAN Dept. 1309, 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.” 8 SESE Se ee oe ea ee eee eae ae ee ee ee Street......22-- 2 ee e n ee e- we CS ee ee eee (Please write or print plainly) POPULAR SCIENCE MONTHLY Wonders of the Sea (Continued from page 129) viding them with highly elastic bodies. This permits them often to swallow creatures almost of their own size. Their eyes may seem a useless gift, since they live in a region where no sunlight can penetrate. It happens, though, that some of them carry their own headlights, for they produce phosphorescent light that probably suffices to illuminate their prey. Their luminescent glow, of course, probably makes them visible to other preying creatures, and this results in their destruction; but thus Nature contrives to maintain a balance even in the sea. The vast majority of the deep-sea creatures, however, are sightless — at least that is indicated by the specimens that have been scooped up by scientists. They find their food by means of their antennae or ‘‘feelers,’’ or through some senses akin to feeling or smell. ggetstinietd you are familiar with the animal life of the upper waters of the sea. There are mammals, such as whales, seal, and walruses, and—fish. The latter exist in almost infinite variety. It would be futile to attempt to describe even a few. Along the shores are other forms of sea life—the clams, oysters, crabs, lobsters, mussels, and shrimps we use for food; the worms, starfish, sea urchins, and sponges; the corals, the sea-anemones. All of these, no matter what their form, are animals. The vegetation of the sea consists en- tirely of the great floating meadows of seaweed, the grass that grows near the shores, the moss that covers the rocks. This, though, plays an important part in the great scheme of the sea, supplying food for some of the sea animals and liberating oxygen into the water so that | the crustaceans and fishes may live. Once, of course, there was no sea. When our earth was formed, the hydrogen and oxygen, the combination of which forms water, were held in its hot crust. | As the earth cooled, the hydrogen and oxygen were liberated, combining into water, and the water filled up the great hollows in the earth’s surface. O CAME the sea to help make} the earth more livable for man who was yet to come. For the sea helps distribute the heat of the sun, yet by the circulation of the icy waters of the polar regions pre- vents the sun from baking the earth. It aids agriculture and purifies the air we breathe by the admirable cycle through which its waters pass in their evap- oration, and later precipitation as rain. It distributes the dust of the earth, for it is the beginning and end of all streams that pass through the land. It yields man a rich harvest in food, and unites the distant dwelling places of the different races of men. It is an unending wonder to the curious, a perpetual challenge to the daring, an everlasting inspiration to all men. Next month Mr. Brown will tell of the wonders of earth’s minerals—mar- vels of nature upon whose use all human progress is founded. FORD RUNs 57 MILES ON GAL. of “GAS” Anautomobile runs 57 miles on a gallon of gasoline by using an automatic device which was installed in less than fiye minutes. The inventor, Mr. John A Stransky, 14-1st St., Pukwana, S, Dak wants agents and iswilling to send sam. ples at his own risk. Write him today, ( " AAR AL oon FORD Vie SPORT CAR ony Other types down to $3.50. Famous sure fit, life. f size patterns and picture instructions show how. ou can tee easily convert your Ford into this fast, saucy Sport Car fhe e as hundreds have done with a ie ’ dollars worth of ma‘erial from the ardware store, No Need to lay op ae car. The . | Keen, Classy | ~4 Up-to-the-Minute =— teen, omy po: M0 de- clive mendertl soe, Onde NOW, eile ees mae . coum thustra . cos oe Tops cna wn on se Windekiolder °F Sport Bodies, KUEMPEL CO.. 533 Kuempel Bidg., Guttenberg, low, Squab Book FREE Squabs selling at highest prices ever known, Greatest market for 20 years. Make money breeding them. Raiscd in one month. We ship everywhere our famous breeding stock and supplies. Established 23 years, Write now for big illustrated free’ boo! How to Make ! ‘oney Breeding Squats, PLYMOUTH ROCK SQUAB CO, ie a "616 H St., Melrose Highlands, May AGENTS 500% PROFIT GENUINE GOLD LEAF LETTERS Guaranteed to never tarnish. Anyone cap put them on stores and office windows, Enormous demand, l1rge 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, Chicap Written For The Latest Fox-Trot Ballad Entitled “PLL 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 Protect your tools from theft. Write any name, eng:ave avy design on tool: and metal with electricity like writing on paper with 2n or pencil. Complete outfit 33.50, prepaid anywhere. Interest- iig descriptive civculays free. Write to-day. Agents wanted Arkograt Pen Co., 1171-A East Stark St., Portland, Oregon) DRESS UP| YOUR CAR $3.85 AND U : CUSTOM MADE {1°03 Jookingtonsnelt Liberty Custom Made Top. It’s fun putting it on, 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. Writetoday for big money saving catalog: Ohi LIBERTY TOP & TIRECO., Dept. E-8 Cincinnati, AC BU VERY pace Sook or ea CARGAINS Containing. a fall line of bodies and accessories at exceptionalls low ” rices. rom the factory. \ ITN") SALES CO. -—SPLIGHTING FIXTURES” Ready to hang. Direct from the manufacturer. |. Completely wired including glassware. , Send for Catalogue No. 2 (Just off the press) Specia! proposition to Dealers ERIE FIXTURE SUPPLY C0 Desk A. Erie, Pa. en How Dehyd the rel the le: made 1 ments along. fruits | are SO good a ~ The institu private the Me purpos plete r may fi cheapé eat m¢ The mer ™ heen ] The n bread, which times there wheat bread, the sa econo! Eve crops destre battle Ifit h gists | count N17 ce tenan that elusiv in fo beri, probe Th still 1 separ and tions for sc of C fourt tress been covel greer fruit As mine the | of th a mi foun clent Goit in j Groy need A thin a lit Moy trun Test; and es

Page 131

port Bodies, — A] tEE er known, ike money nth, We ding stock free boo ing Squabs, QUAB 60, hiands, Mass OFIT TERS nyone can windows, Paul Clark Reel made ay for free ral agents, treet, Chicagn d Entitled ) , write for les NEw York turer. — including ue No. % reSS) o Dealers PPLY 60: Pa. = ete e a How Chemistry Is Feeding Us (Continued from page 45) Dehydration of fruits and vegetables— the removal of nearly all moisture with we least damage to‘the product—has pars rapid advances, but here improve- ments are still needed and are coming long. The goal is to produce dried iruits and vegetables, which, after they ss soaked in water, will be almost as good as when fresh. The bread bakers, too, have a great rnstitute of research in Chicago, besides private laboratories and fellowships at the Mellon Institute and elsewhere. Their purpose is to make bread a more com- nlete ration so that we, the general public, may find ourselves more satisfied with this cheapest of foods, and consequently will eat more bread and less meat. The improved bread uses up the sum- mer milk of the dairy farmers who have yen lacking a market for it heretofore. The milk is dried and worked into the pread, giving it many of the qualities for yhich we eat meat. There is three or four times a8 much milk in bread now than there was five years ago. Using more wheat by stimulating greater sales of bread, and using more milk to encourage the sales, is profitable to the farmers and economical to the consumers. Even in the fields, science protects the crops that feed us. Insect pests may destroy a whole civilization, and the pattle against them must be incessant. Ifit had not been for American entomolo- gists and chemists, the fruit crops of this country would have become negligible. N THE study of foods, research is pro- ceeding also along the line of main- tenance of health. It has been found that unless minute quantities of certain elusive bodies called vitamines are present in food, various diseases, such as beri- beri, scurvy, certain eye troubles, and probably rickets, will follow. The chemical structure of vitamines is still unknown, although it is possible to separate them into four different kinds and to get rather concentrated aggrega- tions of them. Three have been known for some time, and lately Dr. W. H. Eddy, of Columbia University, has found a fourth. Scurvy and beri-beri, both dis- tressing, and formerly fatal diseases, have been practically eliminated by the dis- covery of the necessary vitamines in milk, green vegetables, rice husks, citrus fruits, tomatoes and other substances. As to the requirements of the body for minerals such as lime, iron, potash, and the like, we know now at least how much of these substances should be included in amonth’s ration of food. It has been found that illness usually follows defi- dency in one or another of these minerals. Goiter, for example, follows a deficiency in iodine in food or drinking water. Growing children with growing bones need more lime than their elders. And SO we go on, trying to do the useful taings and seeking always to understand alittle better than before. Science doesn’t | move ahead with a brass band, with | tumpets and drums. No; its progress Tesults from hard, slow work, with here and there a happy reward. ~~ POPULAR SCIENCE MONTHLY The World’s Largest Store is RADIO HEADQUARTERS. Here you can get the famous SILVERTONE neutrodyne_ re- ceiving set or the smallest radio part—at the lowest prices in America. Ce el | 131 Everybody is interested in Radio. If you would keep in step with the progress that has been made in this greatest of all discoveries, you should have our NEW RADIO Catalog just now off the press. You can get the latest and best cqmpeoent from RADIO HEAD- QUARTERS. We have everything that anybody needs to enjoy the entertainment, news and education that are waiting to be brought right into your home. Don’t be without the comfort of Radio this fall and winter when reception is so fine, The World’s Largest Store— RADIO HEADQUARTERS — can — you money on everything you need. “| Sse SUB a eB SB ae eB ee eB eee | Mailthecoupon TODAY to the store nearest you. 91P71. Sears, Roebuck and Co. Chicago Philadelphia Dallas Seattle Send New Radio Catalog. MN aa. atdi a exe ditroelnmirteeis mMeleeadiew Scevcccns WOMGINGES i:0:56oeeiehecwess Mw si cccmuiden Rural Route........... BOS INGiié sin xeeood PRRECGU AMEE INOS oor 2ro Sci cc dicacasenuntuewes sears Roebuck and Co. y 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 make, 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 good 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 an proofs. It is FREE. Act now. OZARKA, INC. CHICAGO 852 Washington Blvd. —do it with a few cents’ worth of Smooth-On No. 1 and you'll get a perfect permanent repair without put- ting anything harmful inside the boiler and without having a big plumb- er’s bill. Smooth-On No. 1 affords the simple, “quick, sure means for stopping leaks in boilers, radiators, furnaces, water pipes and tanks, stove pipes, kitchen pails, etc.. and can be used for hundreds of other house and automobile repairs. The book we send free tells you how to use it, and you can get your supply in 6-02., I-lb, 5-lb. or 10- lb. tins from any live SMOOTH‘ON dealer. REPAIR | SMOOTH-ON MFG. CO. = Dept. 58 574 Ccmmunipaw Avenue, Jersey City, N. J.

Page 132

132 MECHANICS’ HANDBOOK eS. MECHANICS HANDBOOK

330 PACES Morc than 300,000 sold ANDIEST book of its Only kind ever written. Pre- pared by experts under the direction of the Interna- tional Correspondence Schools. Written in lan- guage that you can under- stand. Note this partial list of subjects: Weights and Measures; Easily Under- stood Mathematics; Formulae; Mensura- tion; Belting; Hydro-mechanics; Strength of Materials; Boiler Design; Care and In- spection of Boilers; Horsepower of Boil- ers; Chimneys; Exhaust Heating; Machine Design; Horsepower of Engines; Boilers and Pumps; The Slide Valve; Belt Pul- leys; Rope Belting; Cylinders and Steam Chests; Electricity; Currents; Wiring; Dynamos and Meters; Batteries; Cable Testing; Compass Surveying; Curves; Leveling; Etc. Just mail this advertisement with a dollar bill and your name and address, and this 330-page I. C. S. Mechanics’ Handbook or any of the other I. C. S. Handbooks that you want will come to you by return mail. —— nea a ee | INTERNATIONAL CORRESPONDENCE SCEOOLS | Box 7611-D, Scranton, Penna, | I enclose $..... for which send me, postpaid, the Handbooks marked X, at $1.00 each. It is | understood that if I am not entirely satisfied I may return any or all of them within five days | and get my money back. | 0 MECHANICS’ HANDROOK (Automobile Handbook ORadio Handbook | (JElectrical Handbook L)Salesman’s Handbook (JChemistry Handbook CjAdvertising Handbook | LJBuilding Trades HandbookLBookkeeper’s Handbook } Name PPP er rer terre rirrererer errr err Terre L Address a Drive This

4 iator Shell.

Printers’ wages are now so high you can

7 g for themselves in a short time 6 3 i fe):

POPULAR SCIENCE MONTHLY

semen | » Beautiful Raceabout Instead of Your OLD FORD

Choice of Four Colors; Fiat or the Bullet Nose Rad- Send + for 1924 Free Cat- PRINTING offers Big PROFITS ——~ make big money in spare time CD with one of our printing outfits a No experience necessary. Out instruction book makes every- thing easy. Presses $12 up. Pay Write today for catalog presses, type. ink, paper, cards etc. THE PRESS CO. \ 33 Meriden, Conn. Here Are Correct Answers to Questions on Page 64 1. Because when you go uphill you are lifting your weight against the force of gravity. Thistakes power. When you go down, the force of gravity is with you. 2. They are substances present in very small amounts in many foods and that seem to be necessary to health. Their exact chemical nature is not understood, nor do we know the precise way in which they act on the body. If your usual diet includes meat, milk, butter, and fresh vegetables, you will get enough vitamines. 3. When men first began to study the stars, it seemed that the stars marked out figures in the sky. The ancient Baby- lonian astronomers, thousands of years ago, gave names to these figures and used them as a convenient way of referring to certain stars. Later on this system was borrowed by the Persian and Arabian astronomers and came from them to us. 4. If there were any air inside the bulb, the hot tungsten in the filament would combine with the oxygen of the air and burn up. 5. Science believes that it cannot. Energy is merely changed. Electric energy in a wire may disappear as electricity, but the same amount of energy appears as heat. 6. Because he is in the habit of feeding on the leaves at the top of trees. In the course of millions of years he and his an- cestors have developed a longer and longer neck so that they could reach high trees. 7. The waves of sound in the air strike against something hard and smooth, like a wall or the side of a cliff, and are re- flected back again, much as light waves are reflected when they strike a mirror. 8. 5,885,516,000,000,000,000,000 tons. To get some idea of what this means, think of a tiny dust mote in a beam of sunlight and compare the weighc of this with the steamer Leviathan. The earth is as much heavier than the Leviathan as the Levia- than is heavier than the dust mote. 9. It is a stream of electrons rushing through a wire like a stream of people in a tunnel. Through the filament of an ordi- nary 60-watt electric lamp there pass every second so many electrons that if all the people in New York City were set to counting them and if they counted two a second without stopping for 10,000 years, they would still have a few to count. 10. No. They are far too small. It takes more than a hundred million hydrogen atoms laid side by side to make up one inch. The other kinds of atoms are only a little larger than this. 11. Radium. It is worth nearly $2,000,000 an ounce. Of the ordinary commercial metals, iridium, the metal used for fountain-pen tips, brings the highest price, about $250 an ounce. 12. There are a great many things that happen in our nervous system of which we are conscious only indirectly. For in- stance, when the stomach is empty and several hours have passed since the last meal, the nerves in the stomach lining send messages to nerve centers in the spine and in the back part of the brain and announce that the digestion of the last meal has been completed and that another one can be sent along. The lower nerve centers translate this message into hunger.

Sir Oliver Lodge says this discovery wiJl not become generall until mankind has sufficient wisdom to hand| the power that it will loosen. But Scientist, have already tapped this source of power! No. yet harnessed perhaps but yet plain enough that ANY AVERAGE PERSON can toa large ey tent demonstrate it in daily life. a With the use of this ENERGY you can complish anything humanly possible. This FACT as been proven by the actual experience of thousands of people (Hs the last twelve inn in whose hands we freely placed this einiies discovery. You not only “get the idea” “ted it applies itself to your affairs within a few dea” NOTHING IMPOSSIBLE _ Literally thousands of people changed ve. 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 ele. tricity by turning on the electric light, IT [5 WORTH NOTHING TO YOU. or all men are not equal. Doubt, fear, suspicion, dictryst irresolution are chains that make slaves of many. SEND NO MONEY—JUST THE COUPON Use the coupon below and mail at once. When the Complete Course reaches you sim. ply pay the postman only $2.85; 10,000 others ave 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. : he hopes y known CARNAGEY INSTITUTE, 603 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. PODIDRESDS | 65.<55is:0.a ier ececeee (If you expect to be out when postman calls, send money order or check with this coupon.) “DON'T SHOUT” “T hear you. Ican hear now as well as 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 thow sand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadelphia

AN EXCEPTIONAL OPPORTUNITY to build @ permanent business right in your | own locality! PAYS right from the start, in proportion to the amount of time you can spend. Previous ex perience unnecessary. If you want ' to earn from $75 to $100 @ week regu: 7: mail coupon today for particu: ars to

DOUBLEWEAR SHOE CO., Minneapoli - Minnesota | gavon om | a = oe AME & ith tie liis Sac ll Sart... ... ee ee aa

(ee Buil gdjustn marked Num No. 7 lator tt trolling Num conden Num minal; and Ne Num mounti for use termin: Nun termin positiv throug with tl U! LY ¢] impres detect Nur the pl minals and B the e' while farthe Nu used 1 dense capac Verni termi plate: Nu cond leak Ni necte the ¢ of th to th Ni whic fier :

Page 133

he ho; ly knows ‘0 handle sCientists ver! Not 2 enough large ex. 1 can ac. his FACT rience of ‘€ months amazing ea” but w days, ged their alt Lake be ind prac. n demon. ates elec. ft 0 1s all men distrust, many. JUPON at once, you sim- 00 others > wonder. nciples to lays, you | valuable e instruc- -d, simply ur money 3, “Mak. the post- he Course yundred thou Philadelphia Build a Super-Heterodyne (Continued from page 69) | adjustment. The stationary plates are marked A, and the rotary plates, B. “Number 6 is the A-battery switch; No. 7 the rheostat controlling the oscil- iator tube, and No. 20 the rheostat con- | rolling the first detector tube. | Number 8 is a .002 microfarad fixed condenser. Number 9 is the negative B-battery ter- minal; No. 10 the oscillator tube socket, and No. 19 the first detector tube socket. Number 11 is the honeycomb-coil mounting used when a coil is required, jor use With aerial and ground. Only the terminals are shown on the rear of panel. Number 12 is the positive B-battery terminal of the oscillator circuit. The positive B-battery connection is made through the amplifier units connected with this first unit. UMBER 13 is the pick-up coil LN through which the oscillator wave is impressed on the grid circuit of the first detector tube. Number 14 is the grid coil, and No. 15 the plate coil of the oscillator. The ter- minals of each coil have been marked A and B. The A or inside end of each coil is the end nearer the center of the coil, while the B or outside end is the end farther from the center. Number 16 is the variable condenser | used to tune the aerial circuit. This con- | denser should be of .0005-microfarad | capacity and should be provided with a Vernier adjuster. The stationary plates terminal is marked A, and the rotary plates terminal, B. Number 17 is a .00025 microfarad grid condenser, while No. 18 is a fixed grid leak of two megohms. Number 21 is the plate terminal, con- nected with the amplifier unit. From this the connection goes through the primary of the amplifier unit transformer, thence to the B battery. Numbers 22 and 23 are terminals with which the A-battery circuits of the ampli- fier stages are connected. URN now to the two-stage audio- amplifier unit. Terminal 24 is the input terminal of the amplifier unit; No. 25, the negative A-battery terminal; No. 26 the positive A-battery terminal of the amplifier; No. 27 the tube socket of the first audio- irequency amplifier stage; No. 37 tube socket of the second audio-frequency amplifier stage. Numbers 28 and 29 are louble-circuit jacks. Number 30 is a ‘ingle-circuit jack. Numbers 31 and 36 are audio-frequency amplifying transformers. If you use an- other type of transformer, follow wiring directions according to terminal marking. Number 32 is the positive B-battery terminal for the detector stage that is ‘nected before the first stage audio- lrequency amplifier. Number 33 is a standard 414-volt C vattery; No. 34, a one-microfarad fixed condenser; No. 35 the rheostat used to control the filament current of the two audio-frequency amplifier tubes; No. 38 (Continued on page 134) _—-_-__—_ the | POPULAR SCIENCE MONTHLY What a whale of a difference just a few cents make 4,” —all the difference between just an ordinary cigarette and—FATIMA, the most skillful blend in cigarette history. | 250 Electrical Things You Can Make Yourself Just think of the pleasure it would be to have a good, strong light for shaving. satisfaction of an electric heater giving all the hot water you want—when wanted. things are easily made—you can make them yourself. plained in— ‘*How to Make Things Electrical’’ And there are hundreds of other practical ideas—electrical appliances and devices needed in the house, shop and garage. These time-, labor-, and money-saving devices have all been made and used by the men who tell you how in ““‘How to Make Things Electrical.’’ There is a whole section in this book on Radio. The . m2king of every item in this book is sim- pl.fied by easily followed drawings. There are 313 illustrations. Every man who likes to work around the house, should have a copy of ‘‘How to Make Things Electrical.” Price $2.25, postpaid. Send check, cash or money order to— POPULAR SCIENCE MONTHLY 250 Fourth Ave., New York City Or the These The making of them is simply ex- a

Page 134

You may have the talent to develop into a Saxophone wizard like Tom Brown, of the famous Tom Brown’s Clown Band, and enjoy this most pleasant of vocations; Buescher Band and Orchestra Instruments have helped make famous such leaders as Paul Whiteman, Jascha Gurewich, Clyde C. Doerr, Bennie Krueger, Ben Selvin, Joseph C. Smith, Dan Russo, Gene Rodemich, Henry Santrey, Zez Confrey and thousands of others, $100 to $500 weekly for a few hours a day is not uncommon for musicians of ability to earn. LBOESCHER Pe play. ‘ Peasy pay True-Tone asy = Saxophone The Buescher Saxophone isso perfected and simplified that it is the easiest of all musical instruments to learn. It isthe one instrument that everyone can play—man or woman, boy or girl—and it wholly satisfies that craving everybody has to personally produce music. You can learn the scale in an hour’s practice, play popular music in a few weeks and take your place in an Orchestra or Band within 90 days, if you so desire. Nothing can take the place of a Saxophone forhome entertain- ment, church, lodge or school. It increases the pleasure you get out of life, increases your popularity and your opportunities. FREE Saxophone Book Six days’ free trial and easy terms of payment arranged on any Buescher Saxophone, Cor- net, Trumpet or other instrument. Just fill out and mail coupon on the right for Free Saxophone Book or Complete Catalog. = a1 Buescher Band Instrument Co. Everything in Band and Orchestra Instruments 152 Buescher Block Elkhart, Ind. SECCCCLSSSCSKSS CRTC ESTER SESE EE SERRE REE EERE Ree eee ee Buescher Band Instrument Co., 152 Buescher Block, Elkhart, Ind. Gentlemen : I am interested in the instrument checked below: Saxophone ........ Cornet.......... Trombone...... Trumpet...... (Mention any other instrument interested in) SID isidessst cabin cuebseuestsescepinuesvexctobecosrsbecs sackeveapsescnusioppenipiscee =. . a I ica cctu csicnens aesorensvenssoccneeavsens ® = 5 ic cecouispeictncsasieasiacasesikvelssiscncscntsoese eee aauiaveoes 4 POPULAR SCIENCE MONTHLY the positive B-battery terminal of the audio-frequency stages. The wiring of the receiver is simple. First, begin wiring the oscillator and first detector unit. Practically all leads terminate at the filament circuit, so it is best to wire the filament circuit first. Begin by connecting terminal 3 with the A terminal of battery switch 6. Runa wire from the B terminal of switch 6, con- necting in turn terminal B of rheostat 7, terminal B of rheostat 20 and terminal 22. peta run a wire from terminal 4 to terminal 23 along the baseboard close to the panel. With this wire, join terminal 9, B terminal of fixed condenser 8, F, terminal of socket 10, the outside end B of grid coil 14, the outside end B of the pick-up coil 13 of the oscillator assem- bly, and the F, terminal of socket 19. The A terminal of rheostat 7 is connected with the F, terminal of socket 10, while the A terminal of rheostat 20 is con- nected with the F, terminal of socket 19. Next, run a wire connecting the P ter- minal of socket 10 with the rotary plates terminal B of the oscillator condenser 5. The outside terminal B of plate coil 15 of the oscillator assembly then is connected with the wire just mentioned. From terminal 2 run a wire along the beck of the panel to a point just over the center of rheostat 20; then bend it out and terminate it at the rotary plates ter- minal B of the variable condenser 16. The B terminal of the coil mounting 11 and the inside terminal A of the pick-up coil 13 are connected with this. The inside terminal A of the plate coil 15 is connected with terminal 12 and with the A terminal of fixed condenser 8. The stationary plates terminal A of condenser 5 is connected with the G ter- minal of socket 10. The inside terminal A of the grid coil 14 is then joined to the wire just mentioned. The G terminal of socket 19 is con- nected with the B terminal of grid con- denser and leak 17 and 18. Now run a wire connecting in turn, terminal 1, terminal A of the honey- comb-coil mounting, the stationary plates terminal A of the variable condenser 16, and the A terminal of grid condenser and leak 17 and 18. The wiring of this first unit is com- pleted by connecting the P terminal of socket 19 with terminal 21. Now we are ready for the two-stage audio-frequency amplifier unit. Here, also, wecan begin by wiring the filament circuits. First run a wire from terminal 25 to the B terminal of rheostat 35. The positive terminal of the C battery 33 is connected with that wire. Then connect the F, terminals of sockets 27 and 37 and with terminal A of rheostat 35. Now run a wire from terminal 26, along the back of the panel, to terminal F2 of socket 37. To this wire are joined the F> terminal of socket 27 and the A terminal of condenser 34. In the double-circuit jack the A and D terminals are the outside terminals or springs. The A terminals of all the jacks are the ones nearest the frames. The B How to Build a Super-Heterodyne (Continued from page 133) terminal is the inside terminal that make. contact with the A terminal, while the terminal is the one that makes cont- with the D terminal. 4 Connect the A terminal of jack 28 with terminal 24; the B terminal of the jack with terminal P of transformer 31: ther terminal with terminal B of transforme; 31; the D terminal with terminal 32. The G@ terminal of transformer 3} j, connected with the G terminal of soc 27; the P terminal of socket 27 with th, A terminal of jack 29; the B terminal of the jack with the P terminal of trans. former 36; the C terminal of jac’ 29 wii, the B terminal of transformer 36; the J terminal of jack 29 with the B termina] of jack 30, and with terminal 338. The G terminal of transformer 36 they is connected with the G terminal of soc e 37. The F terminals of transformers 31 and 36 then are connected with the negative terminal of C battery 33. The wiring of the amplifier unit is com. pleted by joining the P terminal of socket 37, the B terminal of jack 30, and the J terminal of condenser 34. The completed units now are ready to be used with the intermediate frequency amplifier and second detector unit. If you complete these two units, you can use them as a three-tube honeycomb-coil non-regenerative receiver. Simply discon- nect the pick-up coil 13 from the circuit and connect the rotary plates terminal B of condenser 16 with the positive A-battery lead, which terminates at terminal 4. Then you can use a 25-, 35-, or 50-turn honeycomb-coil in mounting 11 to act as the tuning element. ONNECT terminal 1 with an outside aerial, and 2 with a good ground. Connect terminal 21 of the detector unit with terminal 24 of the amplifier unit by a wire on the front of the panel between the two binding posts attached to ter- minals 21 and 24. Similarly, connect terminal 22 with 25, and 23 with 26. These last connect the A-battery leads oi the amplifier unit with the A-battery leads of the detector and oscillator unit. Next, connect terminal 3 with the nega- tive A-battery terminal, terminal 4 with the positive A-battery terminal, and ter- minal 9 with the negative terminal of the B battery. Since the oscillator stage is not used, terminal 12 is left unconnected. Terminal 32 serves as the positive B- battery terminal for the detector stage, and terminal 38 as the positive B-battery terminal for the amplifier stages. If a soft tube is used as the detector, terminal B should be connected with 2, B-battery voltage of not more than 22): volts. If a hard tube is used, terminal 3? | may be connected with a plate voltage | high as 671% volts. Terminal 38 should be connected with a B-battery voltage 0 about 90 volts. The voltage of the A battery will de- pend on the types of tubes used. The oscillator tube socket 10 is not used. This receiver is very easy to tune, and will enable you to listen to programs unt! you complete the intermediate frequen | amplifier and second detector unit,

Page 135

ne at makes ile the ¢ Cont>et ¢ 28 with the jack 1; thee nsformer 32, er 31 js of socket With the “minal of of trans. ¢ 29 with ; the terminal 36 then of soe’xet isformers with the 3. t is com- of socket nd the B ready to requency it. , You can -omb-coil ly discon- ircuitand inal B of \-battery minal 4. r 50-turn to act as n outside ound. detector lifier unit 1 between d to ter- connect with 26. y leads of A-battery ator unit. the nega- al 4 with and ter- ‘minal of itor stage onnected. sitive B- ‘or stage, B-battery detector, d with a} han 2 991, rminal 92 | voltage as | 38 should voltage of 7 will de ed. The ised. tune, and ‘ams until frequency | nit. POPULAR SCIENCE MONTIILY Your Own “Super—”’ must function without a fault therefore— Air-Core Radio-Frequency Transformer, Tuned Type (Filter or Very much of the excellence of beat reception depends on the qualities of the filter used. built with the utmost accuracy, to pass an intermediate-frequency wave of 10,- 000 meters (30 kc.) together with the side-band resulting from modulati approximately 26 to 34 _ kilocycles. Other frequencies are effectively drop- ped out, resulting in a selectivity which will surprise even the seasoned ex- perimenter. Type R-120 In building superior tone equally good transformers at the audio-frequency end of almost every strictly high-grade receiver of the beat-frequency type. splendid amplification characteristic are recognized everywhere —hence their widespread use. Type R=12 (Ratio 3 tO 1)... 0.65 sect ieeeeeeees Se Sates ata weds Type R-21 (Ratio5tol)..... Type R-30 (Push-Pull Input. ibd Aah Pricer ee aa Type R-31 (Push-Pull Output) Sierras ae aaa: rs lai eee rain Aca aire) ave rida Rouse ake Price, $6.00 The new RADIO KEY BOOK, just out (48 pages), is the best all-round reference book on Radio Reception and Hook-Ups ever published. You can get it by sending 10 cents, coin or stamps. Send for it now—the First Edition will not last long. RAULAND MFG. CO., All-American coupling throughout for Reliability! Long-Wave Radio-Frequency Transformer, 4,000 to 20,000 meters. (Intermediate-Frequency Transformer, Iron-Core Tyne.) Known and relied upon everywhere for splendid intermediate- frequency amplification, because of the unique design, which provides maximum amplification at 30 kilocycles as well as at other frequencies in standard use, from 15 to 75 kilocycles (20,000 to 4,000 meters.) GESTS) LESSLIS GREE cette Roy Stee en Price $6.00 Radio-Frequency Coupler, Range 150-650 Meters (Oscillator Coupler) The most critical tests have shown that the use of an All-American coupler makes possible a uniform output at any frequency within the range of the in- strument—namely, from 150 meters to 650 meters (2000 to 462 kilocycles). Like the Type R-120 Transformer, this Coupler is perfectly housed in a bakelite case of practical and pleasing design, being thus effectively protected from all iniury by dust, heat, moisture, or mechanical damage. Type R-130........ Input Transformer) The R-120 instrument is . Price, $5.00 Rel eae i eee Price, $6.00 Audio-Frequency Transformers any type of high-efficiency receiver it must not be forgotten that all efforts at quality will be in vain unless the final amplifying instruments are capable of performance. This accounts for the familiar sight of the two All-American All-Americans are not expensive, but their uniform reliability and . Price, $4.50 ..Price, $4.75 .. Price, $6.00 2667 Coyne St., CHICAGO Pioneers in the Industry AMPLIFYING TRANSFORMERS Largest Selling Transformers in the World

Page 136

O reason for you to pay from $400 to $700 for the convenience of a furnace oil burner. For $89.50 you can now have the famous No. 30-A furnace burner—the greatest triumph of the Oliver engineers—an improved and perfected burner listed as standard by the Underwriters Laboratories. The saving to you is from $200 to $500. Save $200 to $500 And when you install an Oliver Burner you have no worry about ex- pensive, delicate machin- ery getting out of order. There are no noisy motors —no moving parts. You do not have to depend upon electricity or gas for operation Yet you have automatic i) heat, dependable toade- gree that was never before experienced — smokeless, sootless, instantly regu- lated for either coldest [== *) Winter, or moderate Fall u . days. This simple device converts any type or size of steam, hot air or OLIVE Res Your Furnace # There are 16 types of Oliver Burners for every kind of heating stove, cook and furnace. BURNER °° POPULAR SCIENCE MONTHLY J hot water furnace into an automatic heating plant. Quickly and easily in- stalled without change to your furnace. Absolutely safe—lasts a lifetime. 200,000 Installations 200,000 homes have tested Oliver Burners— and have banished for ever coal—ashes dirt —smoke— soot —dust — building fires— cleaning furnaces—frozen pipes—exorbitant fuel prices—uneven heat—cold rooms. So great has been the satisfaction of actual users that Oliver Burners are sold on an- extra- ordinary guarantee of complete satisfaction. FREE BOOK— Mail Coupon There is an Oliver Burner for your home, for all types of heating stoves and cook stoves, as well as furnaces. At this amaz- ingly low price you cannot afford to put up longer with the health dangers, the dirt, and _ incon- veniences of coal or wood. An in- teresting book, giving full details, will be sent you free, upon request. Simply fill out and mail the cou- pon below. Get it in the first mail. stove Any degree of heat de- sired, off and on at turn of valve. Excellent for | year round heating. No odor, no wicks. Abso- Furnace Burner. lutely safe. ; Burner. 954 OLIVER BUILDING, ST. LOUIS, MO. Oldest and Largest Manufacturers of Oil-Gas Burners in the World CANADIAN DISTRIBUTOR: 954 OLIVER BUILDING, TORONTO. ONT. ART COLOR PRINTING CO., NEW YORK "BO" Perfected Oil Burner for th a ous Distributors Never before has an opportunity for such substantial profits existed in this field. An $89.50 furnace burner that isa marvel of mechanical perfection, means that every home owner is an interested prospect. Our representatives, whose earnings have always been big, have doubled found their incomes suddenly and tripled. Our business States. Distributors for counties available—turning has grown over to to such a volume that we must now have repre- sentation in every section of the United We are appointing as I xclusive and _scctions, business men of the very highest type them our established business, and in many cases already organized sales forces. Only those who act quickly will cas shin on this wonderful opportunity. present time a proposition can be out: lined to you entirely commensurate wit W rite or wire at once for full details, addressing your ability in present position. Sales Manager. sales agents and spare time Many earn $100 to $250 a week. immediately for sales plan. ) Cook Stove Burner. ( your free book, and full — Is « Teatin Te ee ee he et ee ees ee kn ek ee hee ee ee ee ee es At the We also need dealers, workers. OLIVER OIL-GAS BURNER Co., 954 Oliver Bidg., St. Louis, Mo. Please send me at once ( Send 7

Page 137

0 ors tunity for ‘din. this r that isa yn, Means interested es, whose big, have > doubled o such a ive repre: he United Exclusive sections, hest type hem our any cases All cash in At the n be out: irate with n. Write .ddressing d dealers, workers. ek. Send sil s on o WENTY miles in a single night. That was the wonderful broadcasting achievement of Paul Revere as he galloped from village to village, wak- ing the country-side with the cry, “the British are coming.” Just one hundred and fifty years ago he made that broadcasting record. Today news flashed in any part of the country is heard almost instantly, not a mere twenty miles, but thousands of miles away. In every part of the United States Crosley Radio Re- ceivers are bringing in far distant stations clearly and distinctly. Up to the minute news, concerts, music, lectures, are yours to enjoy right in your home when and from where you choose if you own a Crosley. Keeping always at the head of the procession in improve- ments and innovations, the Crosley Radio Corporation has made it possible for every one to possess the maxi- mum efficiency in radio reception at the minimum cost. The Crosley Trirdyn 3R3 illustrated below is, in the opinion of many experts, the best radio receiver ever offered to the public at any price. The experiments of over 200 experts have shown that in ease of tuning, sharp- ness of signals and nicety of calibration, the Trirdyn cannot be excelled. Local stations may be easily tuned out, even if very close to you, and far distant reception almost instantly brought in. The Trirdyn 3R3, illustrated below, is a 3-tube set incorporating tuned radio frequency amplification, re zeneration and reflex. It has been proven to give the efi'ciency of most 4 or 5 tube sets. And yet it is priced at on.y $65 without batteries, tubes and headphones. The Trirdyn Special, set in a special solid mahogany cabinet which is made to house all necessary accessories, may be had for only $75. : Before you purchase a radio receiver listen in on a Crosley Trirdyn For Sale By Good Dealers Everywhere Crosley Trirdyn 3R3, $65.00 Other Crosley Models Crosley 50. A one tube Armstrong Regenerative Receiver. Price, less accessories, $14.50, A two stage amplifier, Crosley 50-A, may be added to it foi only $18.00, thus making a three tube set. Crosley 51. _ The two tube Armstrong Regenerative set that became the biggest selling receiver in the world in just 24 days. Price, less accessories, $18.50. By adding the Crosley 51-A a one stage amplifier at $14.00, a three tube set may be formed. Crosley 50-P. The Crosley 50 in neat strong Portable quartered oak cabinet for only $18.00. Crosley 51-P. The Crosley 51 in compact leatherette portable case completely self-containing at $25.00. Crosley 52. A new Armstrong Regenerative 3-tube set assuring loud speaker volume on distant stations under almost any con- ditions. Price, without accessories, $30.00. Crosley X-J. One of the best known and most popular 4-tube receivers on the market. A radio frequency set at $55.00 without accessories. Crosley X-L. A rearrangement of the 4-tube Crosley X-J. set ina Hip mahogany console cabinet. Price, without accessories, THE CROSLEY RADIO CORPORATION Powel Crosley, Jr., President 1017 Alfred Street Cincinnati, O. POPULAR SCIENCE MONTHLY Ihe PAUL REV Al Crosley Regenerative Recetvers licensed under} ~ Arms! The Crosley Radio Corporation owns and operates mee E of JODAY trong U. S. Pat. 1,113,149 -GROSLEY. Better -Cost Less Radio Products roadcasting Station W L W MAIL THIS COUPON TODAY The Crosley Radio Corporation, 1017 Alfred St., Cincinnati, O. 9@| Gentlemen: Please mail me free of charge your complete catalog of aw Crosley instruments and parts together with booklet entitled ““The Simplicity of Radio”.