March

FORMERLY ELECTRICAL EXPERIMENTER

THE SLEEP ELIMINAT See Page 1062

etsiti:Ii;ax1ïU11A, -awe sell. tri!lif1112 Go as High as You Like No Limit to Salaries in Aviation No other industry offers the wonderful chances for big money -making that the Airplane Industry offers to ambitious men. Many more trained men will be needed to fill big paying jobs. The airplane has come to stay it will soon be a part of our everyday life. The men who get in now are the ones that will cash in big. Look at the "big fellows" in the automobile game today. They represent power and wealth because they got in early-you can do the same in Aviation and you have an advantage because you can be trained before you start. Thousands of Airplane Mechanics will be Needed The airplane industry is going forward by leaps and bounds. Transportation-passenger carrying and nail carrying lines are being opened up everywhere. This means men- Delivering Newspaper "Extras" by Airplane men-men ! Trained men only are wanted-men who know what's what. Get ready now to make big money. The industry is calling for real red-blooded fellows heed the call-HOW is the time to get started-while the industry is still in its infancy. Here Are a Few Jobs That Will Pay $50.00 to $250.00 a Week: Aeronautical Instructor Aeronautical Engineer Aeronautical Contractor Airplane Repairman Airplane Mechanician Airplane inspector s.rplane Salesman Airplane Assembler Airplane Builder Keep right on with the work you are doing now. A little of Learn at Home your spare time is all TimeyouneCotirneed. Our In Your Spare Special is simplified for home inst'uctiun and is endorsed by airplane \\\\\\\\\'\ A New Seven -Passenger Airplane manufacturers. aeronautical experts, aviators and the lead- S ing aero clubs. Any man who can read English can under - wN stand it. The Lessons are self-explanatory and are made plain (t as day with Blueprints, Diagrams, etc. Our Advisory Council / \QQe and Instructors are behind you all the time giving you every- 1rt thing you must know. The entire field of Practical Aeronautics Science of Aviation is laid right beforeA,\\your Qand eyes. You are bound to succeed withWthis training. This means for you a man'ssize job with a man's size pay. MailSend for our big Bookfree book showing ThisBig SCHOOL just what is going OFAViA77ON A New Job-The Aerial Postman of Opportunities on in the Airplane Dept. 7443 Industry. It also Coupon 3601 Michigan Ave. i shows what other Chicago F R E E men have done in For Without obligation on my this fascinating field and what you can do, too. 'part you may send me your It gives a list of some large book entitled "opportunities in manufacturers and FREE the Airplane Industry" and your dealers in airplanes and some of the jobs that SPECIAL Limitedotïer. are open to trained men. With the book we BOOK will send you a' special offer that you will be glad to know about. This special offer may be Name.._ withdrawn at any time without notice. Send the coupon now and take advantage this offer. ' of Address American View School of Aviation ' in an Airplane Factcry Dept. 7443 3601 Michigan Ave., Chicago 'City Slate 1041 Science and Invention for March, 1923

National Salesmen's Training Association CHICAGO

NOW FREE ! The BookThat Has ShownThousandS theWay to Amazing Salary Increases remarkable, doesn't it? Yet there is nothing remarkable Sounds of Do you want to leave the rut of routine about it. There are certain ways to approach different types work and start right out making more prospects to get their undivided attention-certain ways to stimulate keen interest-certain ways to overcome objections, batter down money than you ever dreamed possible? prejudices, outwit competition and make the prospects act. exactly this for thousands We have done Simple as A B C of men. Here is the book which gave how it is now "Modern Salesmanship" tells exactly how the National Sales- them their start. Read men's Training Association will ,teach you these principles in your offered to you-FREE! spare time at home. As soon as you are qualified and ready, the Association's Em- ployment Service helps you to select and secure a selling position salesman. TAKE this situation : A man who had worked all his as city or traveling life in a routine job at low pay suddenly surprises his Who Will neighborhood, NowFree to Every Man friends, by moving into a better Once taking a big. house, buying a car and blossoming out as a Act at well-to-do and influential citizen in his new community. We are not making any extravagant claims about what we will do is secret that he used? for you. We don't have to. All of the amazing proof and many How did he do it? What the contained in our new knew that the biggest money in important features about Salesmanship are Simple enough. He salary -raising book, "Modern Salesmanship." It is yours-FREE. business is in Selling, and though he felt that he couldn't Send the coupon for it today. It will show you how you can quickly sell a thing, he suddenly learned the secrets that make become a Master Salesman-a big money maker. It will tell you system of Master Salesmen and then began to make big money. about the National Salesmen's . Training Association Salesmanship training-about the National Demonstration method experience while studying-and all about the found inspiration enough in this remarkable that gives you actual If only one man had amazing opportunities that await you in the Selling field. book to jump -to a sudden brilliant success in the Selling field- of your life to leave forever be- you This may be the one big chance into a job paying him many times his former salary-then of a routine job for a sudden, brilliant success might call it luck. But thou- hind you the low pay sands have done it. at a big salary. R E A D! Is it worth 2c. to find out? Then mail this coupon NOW. Charles Beery of Winterset, Iowa, stepped from $18 a week as Your One Chance National Salesmen's Training Association a clerk to a position making him Illinois $1,000 the very first month. to Make the Biggest Dept. 42-C, Chicago, J. P. Overstreet of Dennison, Texas, read this amazing book, Money of Your Life left a job on the Capitol Police National Salesmen's Training Association Force at a salary of less than Dept.. 42-C, Chicago, Ill., U. S. A. $1,000 a year -and in six weeks Not one of the men whose free book, earned $1,800. F. Wynn, Port- Please send me, without any obligation on my part, your names appear in the panel at and- full information about the N. S. T. A. land, Ore., an ex -service man, "Modern Salesmanship." Also a list earned $554.37 in one week. left had ever sold a thing system -of Salesmanship Training and Employment Service. Geo. W. Kearns of Oklahoma, before-not a dime's worth. showing lines of business with openings for salesmen. City found in this book a way to Yet every one of these men, jump his earnings from $60.00 a Name month to $524.00 in two weeks, through reading this book, dis- and C. W. Campbell learned from covered an amazingly easy way Street it how he could quit a clerking to jump suddenly from low pay ob on the railroad to earn City State $1,632 in thirty days. to extraordinary earnings in the Selling field. Age Occupation _,,,,,111111,,,,,,11,,,,,,,.,,,,1,,,,,111111111111111111111,,,1_ ,11111111111.11111111,,,,e,111,,,11,11111111111111a1111111,,. Vol. X March, 1923 Whole No. 119 No.11 FORMERLY ELECTRICAL EXPERIMENTER PUBLICATION OFFICE: EDITORIAL Si GENERAL OFFICES: 542 Jamaica Ave., Jamaica, N.Y. 53 Park Place, New York City Published by Experinu nter Publishing Company,-Ine. (H. Gernsback, Tres.; Publishers S. Gernsback, Treas., R. W. DeMott, Sec'y). of SCIENCE AND INVENTION, RADIO NEWS, and PRACTICAL ELECTRICS

'labile ®f C0ntenti.G SO ir March

POPULAR SCIENTIFIC ARTICLES ELECTRICITY EDITORIAL 1047 THE SLEEP ELIMINATOR CHICAGO -NEW YORK -BERLIN VIA THE AIR 1049 106' By H. Gernsback By Dr. H. Becher WATER -PROOFING RAPID SCENE CHANGES "JOHANNES AND MOTH -PROOFING BY ELEC- IN KREISLER". 1051 TRICITY . By Joseph 1053 H. Kraus By Ismar Ginsberg, B.Sc., Chem.Eng THE SUBMARINE OF.TOMORROW 1053 NOVELTIES AT NEW By Graser YORK AUTO SHOW 1064 Schornstheimer, Naval Expert THE AMATEUR NEW PROCESS COLORS BLACK MAGICIAN 1069 AND WHITE MOVIE MOTOR HINTS-$50.00 FILMS . 1054 IN PRIZES MONTHLY 107o By Lewis Yeager EXPERIMENTAL ELECTRO-CHEMISTRY 1074 FISH THAT HANG UP THEIR YOUNG TO RIPEN By Raymond B. Wailes 1055 ELECTROSTATIC By Dr. Ernest Bade A.C. TO D.C. CONVERTERS 1077 RECOVERING SUNKEN TREASURES 1056 By Clyde J. Fitch HOW -TO _ HOW OLD IS THE WORLD? 1057 -MAKE -IT DEPARTMENT 1078 By Harry Van Demark LATEST PATENTS 1093 THE STAR 1058 THE ORACLE-QUESTION AND ANSWER BOX 109, 24 By H. G. Wells PATENT ADVICE-Edited by Joseph H. Kraus 1115 24 BISHOP WILKIN'S MATHEMATICAL MAGIC 1061 By T. O'Conor Sloane, Ph.D., L.L.D RADIO ARTICLES THE EVER CHANGING GULF STREAM 1061 TALKING ACROSS THE ATLANTIC THE SLEEP ELIMINATOR 10ßn 1062 UNDER -RIVER RADIOPHONE RECEPTION 1081 By H. Gernsback SECRECY IN RADIO AT LAST WATER -PROOFING AND MOTH -PROOFING 1083 BY ELEC- By A. P. Peck TRICITY 1063 RADIO By Ismar FOR THE BEGINNER-NO. 13-HOW TO Ginsberg, B.Sc., Chem.Eng SELECT A HEADSET NOVELTIES AT NEW 1083 YORK AUTO SHOW 1064 By Armstrong Perry DR. HACKENSAW'S SECRETS-NO. 14-THE SECRET .\N AMPLIFIER FOR YOUR PRESENT TUNER 1084 OF THE MOTORLESS AIRPLANE 1065 By Bert T. By Bonaventure Clement Fezandié AWARDS TN THE $100.00 INTERFERENCE HOW ENAMELED IRON TUBS ARE MADE PRE - 1066 VENTER CONTEST 11'86 By H. Winfield Secor ANNOUNCEMENT OF $100.00 BINDING POST CON - MEASURING ONE MILLIONTH OF AN INCH 1067 EST MACHINE 1087 aIAKES 12,000,000 KEY -LESS CODES 1068 COMPLETE REVISED LIST OF RADIOPHONE By H. D. Hunter BROADCAST STATIONS l0ß8 ETHER USED IN MANUFACTURING ICE CREAM 1068 RADIO ORACLE 1091 THE AMATEUR MAGICIAN 1069 By Joseph H. Kraus CHEMISTRY AND ELECTRO -CHEMISTRY SCIENTIFIC PROBLEMS AND PUZZLES 1071 PRACTICAL CHEMICAL EXPERIMENTS 1072 By Ernest K. Chapin PORTRAIT By Raymond B. Wailes PHOTOGRAPHY 1076 EXPERIMENTAL ELECTRO By Dr. Ernest Bade -CHEMISTRY 1074 By Raymond B. Wailes PRIZE CONTESTS WRINKLES. RECIPES. AND FORMULAS-Edited by S. Gernsback 1079 MOTOR HINTS-$50.00 IN PRIZES MONTHLY 1070 THE ORACLE-QUESTION AND ANSWER BOX 1093 HOW -TO -MAKE -IT DEPARTMENT-$30.00 IN PRIZES MONTHLY 1078 CONSTRUCTOR ARTICLES REFRIGERATION IN \VRINKLES, RECIPES, AND FORMULAS-Edited by THE HOME 1075 S. Gernsback By L. K. Wright, Refrigerating Engineer 1079 PORTRAIT PHOTOGRAPHY AWARDS IN THE $100.00 INTERFERENCE PRE - 1076 VENTER CONTEST , By Dr. Ernest Bade 1086 ELECTROSTATIC ANNOUNCEMENT OF THE $100.00 BINDING POST A.C. TO D.C. CONVERTERS 1077 CONTEST 1087 By Clyde J. Fitch AWARDS IN THE $100.00 RADIO INTERFERENCE AUTOMOBILES CONTEST 1086 MOTOR HINTS-$50.00 IN ASTRONOMY PRIZES MONTHLY 1070 THE STAR NOVELTIES AT NEW YORK AUTO 1058 SHOW 1064 By II. G. \\-ells

SCIENCE AND INVENTION is published on the 25th of each month. contributions cannot be returned unless There full postage has been included. ALL are 12 numbers per year. Subscription price is $2.50 a year in U. S. accepted contributions are fur on publication. and possessions. Canada and foreign paid A special rate Is paint for countries $3.00 a year. U. S. coin as novel experiments; good photographs accompanying them are highly destruid,. well as U. S. stamps accepted (no foreign coin or stamps). Single copies, 25 SCIENCE AND INVENTION. Monthly. Entered rents A as second-class matter each. sample copy will be sent gratis on request. Checks and money at Jamaica, N. Y., Post Office, under act of Congress of Starch orders should be drawn to order of EXPERIMENTER PUBLISHING Title 3, 1079. CO., Registered at the Patent Office. Copyright, 192:1, by E. 1'. Co., Inc., toc. If you change your address notify us promptly, in order that copies are New York. The Contents of this Magazine are copyrighted and must nut be not miscarried or lost. reproduced without ghing full credit to the publication. All communications and contributions to this journal should be addressed to SCIENCE AND INVENTION is for sale Editor, SCIENCE at all newsstands in the United AND INVENTION, 542 Jamaica Avenue, Jamaica, States and Canada; also at Brentano's, 37 Avenue de l'Opera, Paris. Member New York. or 53 Park Place. New York City, N. Y. Unaccepted of 1 the Audit Bureau of Circulation.

General Advertising Dept., Western Advertising Representatives. Pacific Coast Advertising Representatives, Kansas Park Place, City Advertising Representative, 53 Finucan & McClure, A. J. Norris Hill Co., George F. Dillon, New York City. 720 Cass St.. Chicago. Ill. Hearst Bldg., San Francisco. Calif. Republic Building. Kansas City, Mo.

1042 1043 Science and Invention for March, 1923

The Creative Power of Mind in Action You Can. Create the Things You Desire MIND is the real motive power behind all creation, both natural and artificial. The Universal Creative Mind projects into the formless mass of uncreated substance a mental picture of a world, with continents, and oceans, and islands, and mountains, and valleys, and teeming life; and in due course the uncreated substance takes the form of the mental picture. The individual human mind, under proper conditions, projects into its environ- ment a mental picture of a splendid home, and forthwith the materials for that home and the money to pay for them begin to move together. The same is true of any other specific thing the individual may desire. What One Thing Do You Desire Above Everything Else in the World ? That desire can be realized. You can have not only that one tiful home valued at Ten Thousand Dollars. This thing, but what things soever else may be necessary for your happi- home is just like what I have been visualizing, even ness. You have within you the creative ability to bring these to the steam -heated, electric -lighted garage." things into existence and into your possession. The Universal this page, and see if you -fifths of your Look again at the picture at the top of Creative Mind exclusively occupies at least four man got his splendid home. He says he and its manifestation in you is called can determine how this brain and nerve -substance, had been "visualizing" it. Can you get things by "visualizing" your subconscious mind. It is infinitely wise. It is infinitely its very them? It is easy, if you know how. powerful. It is all -creative. It created your body from and simple personal message it. It is your Judge Simmons has written a plain beginning, and still repairs, renews and sustains which will actually introduce you to your Real Self. Once the individual entitled, "REALIZATION," Greater Self, your God -Self, your greater, creating, conquering Self, and set you on the way to comes to know his marvelous indwelling Self, and takes it into thou- of his the attainment of the things you desire. It has transformed partnership in his life and affairs, he becomes the architect who will ask for it. If you into his own hand, and sands of lives. It is free to anyone own fortune, the reins of his destiny come to us the coupon at the lower right he wants it to be. will merely fill out and send he makes his life just what of this page, we will send you a copy of "Realization" easy to get acquainted with your Real Self, hand corner It is remarkably full postpaid and and taking it into partnership puts real life into living. Judge Daniel A. Simmons, one of the best known and most successful Absolutely Free of Charge in the world, has introduced a great many practical psychologists fill out the coupon now, before it gets women to their real Selves, and as a result of that intro- We suggest that you men and or something else crowds the matter out of your duction they have acquired splendid homes, fine jewels, vastly in- away from you, creased incomes, coveted promotions, business and professional mind. successes, literary and dramatic achievements, and many other such System of Practical Psychology like things. Many of them who were sick have healed themselves The Realization of nearly every kind of stubborn disease, and some of these heal- ings have been truly miraculous. We have their reports of these THE REALIZATION SYSTEM, things-a great mass of them-in our files, and since we have used Law Exchange Building, Jacksonville, Florida. the picture of a home at the top of this page, we here quote from I accept your offer to send me free and postpaid a copy of Judge Simmons' reports which tells about the acquirement of a personal message entitled "REALIZATION," with the understanding that I just one of these thereby incur no obligation of any kind whatsoever. home. "It seems that lately everything is coming my way, NAME just as though I were being carried forward by some STREET, or R. F. D. a business deal came unseen power. Only this week CITY , STATE to me which placed myself and family in a most beau- S. I.-3-23 1044 Science and Iivenlion for March, 1923

THE BIGGEST SUCCESS IN RADIO: 5Oc EACH CONSOLIDATED RADIO CALL BOOK CO'S. EACH PATTERNS and DIAGRAMS 50c Complete Patterns, Diagrams and Instructions How to Make Your Own 1 A RADIO FORMULAE SHORT WAVE REGENERATIVE `'t AND DIAGRAMS RADIOPHONE SET Usefulness!

Economy!

Pleasure!

!II'iìk'IIIIIIII'III!illlilllll!lìiuìn- 50c One of the foremost Radio engineers constructed this set for us; it's simple to follow our patterns and assemble the parts comprising this set with which spark, C. W. signals and Radiotelephony may be received. With this packet of radio knowledge you need never worry about We don't only give you pictures of how the apparatus looks, but each schematic wiring diagrams. measurements and radio tables. All for- pattern is full size and printed on heavy blue print paper. Only stand- mulas and diagrams are printed on heavy paper in black and blue; and ard parts are used. contained in two-color printed envelope. 9x12 inches, SENT POST-PAID I PATTERN No. I Consisting of a Five-Page Illustrated Direction Pamphlet, size 8BF2x111.L ALL inches, One Blue -Print pattern, size 16x22 inches and One Blue -Print ABOUT AERIALS pattern, size 171x22 inches, all contained in a heavy Two -Color printed Envelope. 9x11 inches. 12 Diagrams How to Construct and Erect SENT POST-PAID All Types of Aerials DETECTOR and AMPLIFIER RADIO UNITS RECEPTION and TRANSMISSION ALL FOR CDXfOIIDA,i; ÑDID CATI BOGY. (O. 50c

THESE ARE DIAGRAMS THAT EVERYONE with a radio set wants and needs. These blue prints were made of each aerial, and after practical erection You can build this detector and the amplifier units anywhere in your point out to you how simple it is to erect not only house; no machine the proper aerial for your particular need. but shop is needed. When built they may be used with in the most practical how to erect this aerial any type of Regenerative Receiver or short wave set, with which spark, manner and at the least expense. C. W. Consists of 12 blue prints 8?,_x11 inches Signals and Radiotelephony may be received. We've tested these tion and one four -page instruc- patterns by actually building the outfit-they're perfect! Only standard pamphlet 81/2x11 inches. All contained in a heavy two-color printed parts are used in making the outfit. envelope 9x12 inches. SENT POST-PAID I PATTERN No. 2 Consisting of a Four-Page Illustrated Direction Pamphlet, size 8/2x11'/, 20 Radiophone Diagrams inches, One Blue -Print pattern, size 16x18 inches. and One Blue -Print and pattern, size 13,/.x15 inches, all contained in heavy, Two-Color Printed Envelope, size 9x12 inches. Hook -Ups of SENT POST-PAID Crystal and Audion Receiving Circuits, Amplifier Circuits, RADIOPHONE CRYSTAL SET Regenerative Circuits, Sending Circuits with Key Chart of Symbols and Pamphlet "How to Read Diagrams" :. r>~= n ;é hvent ,:a 50c 10Pi0IE These diagrams show 47-- .how to get the best pos- aQETA. AND - We designed {.ssRYWMWIDOW .mYDr cats uVSra"s`".+oops, ....:- sible efficiency from the these patterns especially for those who are without Dsf.sflaMG C{>mn 1 ' instruments technical knowledge Fa..l Awe* w-B..BI...ArX3^, you make or but who are sufficiently abreast of the times to de- ':.!%- purchase. They cover sire a radio receiving set in their homes. An instruction pamphlet m+w(m;rtóliAóló B}DDORtb.la .- hook-ups comes along from the sim- with the blue prints and all you have to do is follow the plest to the most com- simple instructions. This radio set can be tuned in from stations within plicated, in 1;0 miles. a way that Standard materials only are used. any amateur can under- stand and follow without PATTERN No. 3 difficulty. Get this set, I and hook up right. All 20 diagrams Consisting 4 are printed on heavy paper. each sheet size 8t/ax11t,, of -page illustrated Direction pamphlet, size 81/1x11% inches, inches. and together with KEY one Blue-Print pattern size 16x22 inches. All contained CHART OF SYMBOLS and pamphlet printed envelope, in two-color "HOW TO READ DIAGRAMS" are contained in a heavy two-color 9x12 inches. printed envelope, size 9x12 inches. SENT POST-PAID SENT POST-PAID

ORDER FROM YOUR DEALER-or direct from us CONSOLIDATED RADIO CALL BOOK CO., Inc. PUBLISHERS 98 Park Place NEW YORK CITY Science and Invention for March, 1923 1045

rello lllll .:-r------_ THE HALL OF FAME Will There Be A Niche For You ? NO man knows what is in store for him. Men now famous in business and scientific worlds were obscure only yesterday. Men today unknown may leave their names in the HALL OF FAME. Great discoveries have Industries Need been born over night-marvelous scientific deeds sometimes were the re- sults of decades of labor, other times the outcomes of a scant yveek's re- Chemists --- search. Truly, no man can tell what the future holds for him. But it is within the power of each and everyone of us to control our own destinies, Pay Them Good Salaries by self -training and diligent study to fit ourselves to render a lasting service to the world-a service that will bring reward, perhaps in fame, perhaps in Industrial plants of all kinds havr riches. You control your own future. awakened to the need of skilled, trained chemists. Good salaries are paid them. There is no reason why you, too, cannot Great Growth of Chemistry join this small army of trained men who are reaping material benefits from their IT 'hat It Meats to YOU knowledge that guards and advances It is the growth of chemistry that has made the past century the most ciyilirationt wonderful period in man's history. In a few years the chemist has changed the industrial customs of the world. In a little more than one century he has advanced civilization by ten centuries. Do you know you can learn chemistry at home in your leisure hours? You can-hundreds of others ---and Special arc learning now! Dr. T. O'Conor Sloane Will Teach You Chemistry 30 -Day Offer! in Your Own Home Besides furnishing the student with his Ex- The Chemical Institute of New perimental Equipment, we are making an York. of which Dr. T. O'Conor additional special offer for a short while only. Director, was You owe it to yourself to find out about it. Sloane is Educational book. founded to fill the need of ambi- Write today for full information and free tious. far-sighted men who realize "Opportunities for Chemists." Send the coupon the splendid future right now while it is fresh in your mind. Or and recognize on a postal and chemistry- offers them, but who just write your name and address cannot spare the time nor the mail it to us. But whatever you do. act today. money to attend college. Dr. Signing the coupon may prove the most important Sloane. a foremost authority on event in your life-mail it at once and let our chemistry, will teach you and will book give you the facts. give you any individual help you may require. Ile will personally go over your papers. correct- them, point out your faults. and place you on the path which bears foot -prints of many who have trod it on to the HAI.I. OF FAME. Act Now! Experimental Equipment Furnished to Easy Monthly Payments Every Student You don't have to have even the We Live to every student without additional charge small price of the course to start. CHEMICAL INSTITUTE OF NEW YORK this chemical equipment, including forty-two pieces You can pay for it in small monthly Home Extension Division 3 of laboratory apparatus and supplies, and seventeen payments-so small that you won't New City of our course 140-D Liberty St., York different chemicals and reagents. These comprise feel them. The cost any obliga the apparatus and chemicals used for the experimental is very low, and includes every- i'lease send me at once without box the Experimental Equip- tion on my part, your free Book, "Opportunities work of the course. The fitted heavy wooden thing, even about the Ex- serves not only as a case for the outfit but also as a ment-there arc no extras to buy for Chemists." and Rill particulars Our plan of perimental Equipment given to every student. Also useful laboratory accessory for performing countless with our course. and special experiments. Pull particulars about this special fea- monthly payments places a chemi- tell me about your plan of payment ture of our course are contained in our free book,. cal education within the reach of 30 -day offer. "Opportunities for Chemists." everyone. NAME. Chemical Institute of New York, Inc. ADDRESS Home Extension Division 3. 140-D Liberty' Street, New York City CITY S. c t 1(1-16 Science and Iiivention for March, 1923

Master Electricity By Actual Practice The only way you can become an expert is by doing the very work under competent instructors, which you called will be upon to do later on. In other words, learn by doing. That is the method of the New York Electrical School. Five minutes of actual practice properly directed is worth more to a man than years and years of book study. Indeed, Actual Practice is the only training of value, and graduates of New York Electrical School have proved themselves to be the only men that are fully qualified to satisfy EVERY demand of the Electrical Profession. The Only Institution of the Kind in America At this "Learn by Doing" School a man acquires the art of Electrical Drafting; the best business methods perience and ex- in Electrical Contracting, together with the skill to install, operate and maintain all systems for producing, transmitting and using electricity. A school for Old and Young. Individual instruction. Over 8,000 Graduates are Successful Men in the Electrical World No previous knowledge of electricity, mechanics necessary or mathematics is to take this electrical course. You can begin the course and, by steady now application prepare yourself in a short time. You will be taught by practical electrical experts with actual apparatus, o:oroi.o 4ib actual conditions. under 1114::.¡ The N. Y. E. S. gives a special Automobile Ignition ::r.rorr advanced Course as an training for Auto Mechanics, Garage Men and Car Owners. Im The -,mow course covers completely all Systems of Ignition, Starters, Lighting and other electrical equipment on automobiles, motor boats, etc. airplanes, Let us explain our complete courses to you in person. If you can't call, send now for 64 -page book-it's New York Electrical School FREE to you. 29 W. 17th St., New York, N. Y.

Please send FREE and without obligation to me your 64 -page book. New York NAME STREET Electrical School CITY STATE 29 West 17th Street, New York r te ,.,,,,,,,,111,1,,.1,,,,,,,,,,,,,,,,,,,,,,,,,,,,,1,1111,,,,11111,,,,,,,,,,,, n MARCH Volume X ,a,', 1923 .\\;. 4,9 ` No. 11 Whole No. 1 19

111111111111111111111111111111.1111111111111111111111111111111/11.1111.111.. H..GERNSBACK, EDITOR AND PUBLISHER H: WINFIELD SECOR, ASSOCIATE EDITOR T. O'CONOR SLOANE, Ph.D., ASSOCIATE EDITOR Editorial and General Offices, - - - 53 Park Place, New York "Those Who Refuse to Go Beyond Fact Rarely Get As Far As Fact"--HUXLEY rfirlAy s ? or gas, the outer E often hear the remark, "as empty as space, Besides this tenuous atmosphere of. floating matter, which we utter frequently, quite unthinkingly, space contains a tremendous amount There is not a having accepted the theory that space indeed as can be proven readily by.: anyone. long enough, you will is empty. But is it really? When we sum up single night when; if 'You watch stars illuminating the the evidence, and there is a good deal of it, we find that not see one or more shooting such shooting stars, it is safe to space is not at all- empty, but on the contrary is filled sky. And if you -see 'of observers who are watching up with a great quantity of matter. When we say that say that other millions every night. We know space has no atmosphere or gases, we must take this for them, can see them as well stars are. They are meteorites, with a large grain of salt. To be sure, let us say, half- what these shooting iron, that drive into our way between the earth and Mars, or between the earth usually composed of metallic reduced to metallic dust, which, and Venus, if we could "sample" a bit of this "vacuum," atmosphere, there to be has exploded, falls down harmlessly we probably would be surprised to find that it was not after the meteorite in a a big meteorite crashes so nearly complete as we once thought it was. As a to the earth. Once while as large as a small house have. been matter of fact, scientists tell us that there is no such down and specimens of the larger pieces are preserved in our thing as a 100 per cent vacuum anywhere. found. Some museums. But we do not see, by any means, all of these prove we know, as a fact, that the earth To this, meteorites. There is a tremendous amount of meteoric is gradually losing a good deal of atmosphere as the (lust floating about in space, ,.aimlessly, which, if it . for instance, the moon once upon years pass by. Thus, strikes the earth, has not suffieie t speed and mass to a had an atmosphere the same as the earth, but due time make any great pyrotechnic display. Such meteoric pull is so much lower to the fact that its gravitational matter settles down slowly upon the surface of our out into than that of the earth its atmosphere passed planet. space more quickly. Physics teaches us that nothing It has been calculated that the sun alone attracts is lost in nature. Where, then, did all this atmosphere enough of such meteoric matter in the course of a cen- of the moon go, and where does the atmosphere that to amount to a mass that is as great as our moon- the earth loses in the course of centuries go? We also tury a tremendous amount. If the earth is between 20 and 35 know that Mars is losing its atmosphere and has lost millions of years old-that is, if it has formed a crust the greater part of it already, so that there is only a for this length of time as our geologists assure us- fraction left of what there was before. All of this air and if only 100 tons of such meteoritic material falls or gas of countless celestial bodies, be they stars or the earth each day (this is a conservative planets, has spread through all space, where it can still down upon you can figure out for yourself the tremend- be found, although, of course, in a very attenuated con- estimate), ous amount of material that must be floating in space. dition. And we must not forget that at certain times of the We venture to say that average space contains a vac- year, when we pass through one of the large meteorite somewhat better than that in our ordinary electric' uum swarms-which meteorites are the remnants of de- light bulb, which, as we know, is only a poor one, stroyed planets-the amount of matter that is thus de- technically called "a soft vacuum." This vacuum is not posited not only upon the earth but upon the moon as to be compared at all with, for instance, that found in a well as upon other planets, amounts to a colossal figure. high grade amplifier tube used for radio purposes. The when man finally perfects his rarefication in the latter is far greater than that of the It is safe to say that problem will be, not how ordinary incandescent lamp. So we see that the outer "stellar express" the greatest from one to another, but how to safeguard space probably contains a good deal of gases which, to get planet impact of meteorites traveling at a while very tenuous, are not at all to be compared with the flyer from the 5 30 miles per second. the next -to -impossible absolute vacuum. speed anywhere from to H. GERNSBACK. 1047 BfIRLIN^N AyT EoAIR_CVO

I t.

"CABIN CABIN DOORS OPEN ON PROMENADE t .w..-ever",:

(longitudinal The view showing tb' various compartments along the promenade deck of the new giant dirigibles, being built for the Berlin-New York-Chicago air truffle. Nate how comfortable the passengors will be while flying through the air at an altitude of several thousand feet. Meals of course, be served en route, and as the other pictures on will. this page show, the passenger compartment is of different design than that followed in previous aircraft of this type, in that the cabins are all amassed in one continuous section in the forward part of the ship. One can steep in perfect comfort on these giant airships, minus the noises encountered in railroad sleeping tars.

V .ew along the promenade deck of the huge trans - This view :lows the interior of the airship Cmmraander s cab, the h.rinontal Atlantic dirigible. These decks will be lighted by and vertical rudders teiag operated by means of the wheels shown, while The Schotte. Lanz air.h lip lin the electricity and glass panels in the rail shelf will per- the handler at the right control the various engines driving the propellers. course of construction in German mit the passenger to look directly downward. The Irons of the cab, as will be noted, is made of glass all the way down. factory, less the external sküs,.

View looking a on. the 'catwal-t ' viti gasoline rest ry r and wate- Batas - sacas

STERN

T.is ph.to shows the tirs framework and rt. eri eg rudders n .-ocect of construc- tins.

1048 C icz C:2 New ITOTM ©Ain Ila, t e y Dr. H.BECHER

the world, must be maintained. In short, of business is nowadays no longer guaran- WE learn by making mistakes," by We learn to high working expenses are incurred con- teed. Over-sea letters go too slowly runs an old saying. is done and to avoid dangers stantly which in some way have to be re- steamer. This obvious deficiency overcome by means of the. air -service Ct as we have but once imbursed. away with as soon a low charge and come into contact with them. In the aeronautic service matters are quite which at comparatively ports. in a very short time carries most important Germany has undergone this experience dur- the same; here also we need ships and her aerostats But there is one profit compared with the news from one part of the earth to another. ing the war with regard to letter weighs very little, the charge for forced her in these four years navigation service, i.e., that in the free at- A when necessity no forwarding it can therefore be small. It of to run through a period of develop- mospheric ocean we need no light -ships, war charting of channels, etc., and that thus a does not at all appear utopian to think that ment of thirty years as far as devising and mere final considerable part of the running expenses in future times on certain routes constructing aerostats is concerned. The post -aerostats may be in service which do had been an excellent connected with the ocean service does not product of endeavors come into existence. not take any passengers at all but forward model of inflexible aerostat, the Schütte - exclusively mail and matters or goods of Lane. Fully appreciating the merits of this, high value. The American Mail -Service, leading American concerns of commerce and had excellent re- Dr. la the present article by Dr. H. Becher, for instance, has already' industry established in connection with one of our Berlin contributors, we are sults in forwarding letters from New York Schütte, the General Air Service, a branch told of the newest plans for a trans -At- to San Francisco and back again by airplane. Cor- lantic air service in which the latest affiliated to the American Investigation be service is arranged in such a manner call aeronautical developments are to ap- This poration, who in the near future will plied in building huge gas -filled airships, that an airplane carries the mail during into existence a regular aeronautic com- which are intended to link Berlin with having The financial the first light -day period after mercial traffic first of all in America. The New York and Chicago. started. In the evening of that day the a and other arrangements have, it is said, project is to raise in America preliminary already been completed, and the present mail is delivered to a fast -train going in share -capital of 50 million dollars which is plans call for the building of three large the desired direction which again in the to be increased afterwards and to build three dirigibles, of the type shown in the pho- morning gives the whole matter to another balloons or tographs on the opposite page. The large Schütte -Lanz dirigible dirigibles are of the Schtitte-Lacez ,type, airplane for delivery at destination. For- aerostats of about 110,000 cubic metres ca- and every precaution is *to be taken is warding at night by means of airplanes is pacity. Setting these going a regular traffic the pleasure machines to guard against not possible as yet, because flying and land- line New York - explosions or fire. It is intended to fill will be opened up on the the balloon compartments with non -in- ing at night for a vehicle like this is still Chicago to begin with; a second line, New flammable helium gas, and the builders too dangerous. is to follow soon after. are planning to replace the benzine mo- York -Berlin, heavy few may here be allowed on the few single aerostats only will tors with those to be operated with A 'words Of course, a The engines are, moreover, to be would will have to oil. relation of aerostat to airplane. It not answer the purpose. There placed in separate gas -tight rempart- be to believe, that they should ex- well provided of their own. wrong be created besides large ports, ments clude one another or be in competition with with gas -works and hangars to house the include each other. On the contrary, they must aerostats and the hangars must be necessary supplements capable of being both considered stable ones and some Careful and thorough calculations of the to one another, the aerostat representing a turned. There must be set up masts for profit have thus far shown that in an aero- for affording fast -communication for large distances, anchoring, provisions made nautic service suitable to all modern require- its rapidity telegraphy and the are while the airplane with greater refuge, etc.; wireless ments passenger prices will suffice which but its present still much smaller radius of meteorologic service will have to be adapted but little above first class passenger prices of aerial traffic. The dif- In fact, action, comes preferably into question for to the necessities of our modern saloon-steamers. small distances. ferent countries will have to work together taking here into account the saving of time, for which purpose international agreements the air service will really be cheaper than a If we should sketch out upon a globe an will have to be made and all progress of steamship- or railroad -service, for "time is air -service comprising all parts of the world, technic must carefully and continually be money"; this proverb being to -day more as we might expect for the future, we studied so that the necessary development valid than ever before in every business pro- could limit ourselves to a few, say about a will neither be stopped nor retarded. ject. For instance: The highly paid corre- dozen lines, representing all routes from And besides, the whole project must be spondent of one of the large newspapers one country to another and beyond it. At in a manner so it will turn out has to be travelling constantly all over the the ends of these routes a fine net -work of carried out lines would represent the short -distance to he profitable. If you mention to an out- world ; he must be everywhere where there sider the approximate sums necessary for is "something going on". If this corre- routes of the airplanes within the different constructing one single aerostat of large size spondent, in using the air -service, has to be countries themselves. or for creating a well equipped port, he idle but one month a year in all, instead of Finally a few words on the security of will in turn doubtfully shake his head and three months as by using the steamship- and the aerostat. express his opinion that to his mind it would railroad -service, the profit for himself and The gas -filling is generally considered to seem impossible to find any subscribers to a his newspaper will most probably be some be very dangerous. The hydrogen con- project like this. And yet he is wrong ! Com- hundreds of times larger than the somewhat tained in the halloonets mixed with the at- parison will show better than figures and higher price for using the air -service "-ould mosphere, forms, it is known, an explosive counts could do, where the fault lies in the amount to. mixture. Consequently, on board the aerostat reasoning of this critic. If you travel to- Another example: If a representative of every possibility of an explosion must be day on board of one of those huge t.odern finance, of commerce or diplomacy, or the avoided and there must he no possibility of steamers from New York to Hamburg, you reporter of a newspaper of world -renown, conflagration. This aim has been attained do not think for one moment-and surely no has to go from New York to Berlin, it will in practical manner in which there is of one else does-that this steamer might just take him at least 8 days to travel by steamer special importance the discharge of gas as well go back and forth doing her service and by railroad. If the air -service on this which Schütte -Lanz has adopted in his sys- without properly built ports containing route were a fact to-day, it would not take tem in the shape of gaspits. A second dan- docks and quays and all requirements for him more than about 2 . to 21/2 days. The ger which is also connected with the air- proper landing, discharging and re -loading. great saving of time is obvious. plane, is the benzine motor which nowadays On the contrary, everybody knows that in A means of traffic for niultitudes ,he air- is still necessary for driving the aerostat. the harbors of all large seaports millions of service will never be, because the carrying Benzine -vapors are easily set ablaze, but dollars are invested. Everybody knows fur- capacity of an aerostat is too small as com- even this danger is not to be taken in earnest ther that compared with these sums the pared with the running expenses of the on board of a modern aerostat. The motor cost of building the steamer herself counts whole service. An aerostat like that which plant, for instance, is put into special tightly Almost as a mere trifle. As a matter of Schütte -Lanz intend to put into service be- closed gondolas which hang at quite a dis- course extensive measures have to be taken tween New York and Germany, can take tance from the main body of the aerostat, for securing navigation on the ocean as about one hundred passengers only, but there being thus always a strong current of well as on rivers, exact sea -charts must these will certainly enjoy all the comfort air passing between the gondola, the source necessarily be drawn up and constantly con- which the travelling public is accustomed of danger, and the balloonets in their casing. trolled, the navigable road must be regu- to on board of the modern fast steamers. In consquence of this arrangement there lated, dangerous spots marked by light- As a second important factor in the profit would be, evert if a little fire should occur houses, light -ships, and buoys; and last but of air -service we must mention the inside of the gondola, no harm whatever not least a regular and well organized me- mail -service. Cablegrams and radio -tele- done to the ship itself, as experience has teorological service, encircling all parts of grams are very expensive and the secrecy shown. 1049 BE/thi )IFECTIK: GERMAN friR 390T \

.jo on. 4.. etelos "Am 4110e -..e»: 'Mime%

?.LA HANDS G

CHM,. GN[ 5CEMEPYTHLf

PER MAN. SETT(NG

DEE.CE1T P_NUCFM

OPC,HETP DiF ECTOR'S 130X

COUNTER- WEIGH-

ROLLEFe -- Hoe --1EADS--- ARE CUT OFF

In "Johannes Kreisler," the latest New York theatrical srnsatict, there are forty-one scenes, which are changed right before the audience without drop- ping the curtain. These marvelous scene changes are effected by switching off the lights, the stage attaches being garbed in black; these rapid trans- formations being aided by a nurabet of clever moving Scenic structures, as shown above. 1050 cne C]hang©2 hi enne2 9 By JOSEPH Ho KRAUS mak- spectacular produc- tre to steep himself in Mozart's music. He upon a mirror, which reflects the light ONE of the most change the location tions on the American stage today explains that Donna Anna, Julia, and Eu- ing it possible to rapidly by thousands phemia are all one and the same-his Un- of the beam, in much the same manner as is now being viewed reflect sunlight, of theatre -goers daily at the Apol- dine. He adds that although Donna Anna a boy with a mirror can pro- was at the moment on the stage, he felt her directing it very easily toward any spot de- lo Theatre, New York. This employing imported from Germany, where presence behind him, the scene changing to sired. These lights instead of duction was large colored screens, use a strip of col- it was first shown under the name of "Die indicate this. The bell rings, and Donna des Kappellmeis- Anna must return to the stage. While sing- ored gelatine only one inch wide, and about Wunderlichen Geschichten from a vivid ters Kreisler." Svend Gade, a Danish in- ing, she stretches her arms alluringly toward six inches long, blending colors over to construct Kreisler, who drawn by a super -natural violet to the other or red extreme of the ventor, was also brought this back and forth just the stage and produce the scenic effects, he force, floats from his box through empty spectrum. Sliding of rapid space, down to her on the stage. This takes a little out of the focus of the beam of light, being the inventor of the system being used. In the play, forty- place supposedly at two o'clock in the morn- where the rays concentrate before scenery changing mirror, it is possible to one scenes are to be counted; there are ing, after Kreisler had fallen asleep in the thrown upon the in the second theatre box. They embrace, and a moment rapidly change the color. An iris diaphragm twenty-one in the first act, ten dollar, in third act, all of which later she lies lifeless in his arms. The scene slightly larger than a silver controls act, and ten the light. spot -lights are pass before the eyes of the audience within the amount of These of two and one-half located upon a special gallery erected just the prescribed period 1111111111111111111111111,1111111111,111111,,,,,,11,11,1111,11,,,11111,,,,1.,,,,, .1,,,,,, 01,11i,,,,,.11,,,,,,11,,,,,1111 hours. There is no intermission at all be- back of the proscenium arch. tween scenes. The orchestra pit is entirely covered, the AprIlfl Feature the through an Just a féw words with regard to the story director observing scene the play itself, will be given and then we elongated prompter's box. A flight of stairs of ArtIlcIles Ilya ScIlence leading the roof above the orchestra will continue with the description. Part 1- from an opera in and extending below the stage, permits Johannes Kreisler has written and Bmven@Il®n later in is star, Undine being a Kreisler to go down to a platform which Undine to to the musicians i- the in the opera. Kreisler is be - the play, direct character scene when the opera is being staged. This f riended by Julia, a girl whom he meets, and Measuring the Heat From the flight of stairs is covered by removable is invited to her house by Julia's parents, of he subsequently teaches her to sing. Planets. By Donald II. Menzel, M.A. traps. Extending from the forward edge where the orchestra box (for the pit now is a sec- A Padre tries to persuade Julia's mother to The Thing From-Outside. By and warns her against tor of a circular box, the orchestra being have her take the veil, George Allan England. completely covered), an immense gauze cur- the musician. A rich man also enters and the hand. On a subsequent Producing Burning Ship Scene on tain rises upwardly, being attached at proposes for Julia's an iron supporting rail. The visit, Kreisler is told that the Padre has Stage. upper end to mass, in him, gauze curtain itself is painted. This pro- taken Julia to which creates The Birth of a Clay Pitcher. By change of behind it, when visions. He sees Julia tied to a vides for a scenery maddening Jay B. Elliott. one of the smaller stages is illuminated, whipping post, with the Padre scourging her lowering regu- unmercifully. As Kreisler cries out, the Talking Over 70,000 Volt Trans- without the necessity of the post By "Wired Wireless." lar drop. The audience can see through the scene rapidly changes, and the whipping mission Line gauze is illuminated, becomes the convent cross, before which curtain when the stage Utilization of Tidal Power-Latest but when stage is in total darkness it Julia is praying. They return to Julia's room the has European Development. appears as though the curtain itself was and the rich man enters. Again Kreisler absolutely opaque. Strange to say, the actors man is seen offer- Wave Traps and Interference Pre - a vision in which the rich never see the audience. ing hoards of gold to Julia. Kreisler enters venters. By A. P. Peek. upon this scene, where the money bags turn In order to facilitate the changing of the How to Build an Ultra-Selective scenes rapidly, the stage has been divided up into skulls, skeletons, and spooks. Again the Wave Tuner. scene changes to Julia's room, where she and Short into six smaller stages, which may he al- Kreisler have an understanding. She in- What Will Be the Future of Radio most completely drawn out of the way. forms him that she doesn't want riches, but Broadcasting? By H. Winfield Secor. There are three sets of longitudinal tracks, upon which flat platform -like cars roll, wants him. Just then, as they embrace, the Producing Helium From the Carbon Padre enters, and Kreisler is ordered away. which may be drawn forward or pushed Arc. back whenever desired. On the center plat- Part 2.-Kreisler, now musical director of form smaller settings are mounted and on the Royal Opera, is commanded to appear at Pipe, Cigars or Cigarettes-Which? By Ismar Ginsberg, B.Sc. Chem. Eng. the two platforms on either side running the Grand Duke's Palace, to play music for parallel with this, some of the larger scenes a dance. He refuses, but Euphemia, the All the Earth's Atmosphere in One are erected. Each of these platforms con- Duke's niece, coaxes him to play for her Tank. By Charles Nevers Holmes. tains a double story structure, the upper pleasure, which he does. Kreisler's rivals story of which extends considerably be- and enemies mock him. The Lord Chamber- yond the lower one. This particular con- lain, having proposed to Euphemia, adds to struction may he shifted at right angles to the Grand Duke's worry over her growing the platform upon which it rests, as it intimacy with Kreisler, but she assures him changes to the room where he is telling also moves on rollers. Thus it is possible she will do what is right. Kreisler seated the story, where Kreisler is informed that to construct a bridge with one of these on at his desk writing in the following scene, the opera would not he played because either side. Either a complete scene or a is tortured by oppressive imaginings, his Donna Anna died at two o'clock that morn- half scene may be erected on the half enemies standing about him, laugh at him, ing. Kreisler closes his eyes, and falls into bridges. and with his baton he cuts their heads off. a slumber from which no one can arouse Each bridge is equipped its sup- This beheading scene is shown in detail in him, his soul passing to meet his Undine, with own the insert in our illustration. The scene ply cable and electric lights, and at no time or otherwise Euphemia, Donna Anna and are the usual footlights of the stage or changes to one at the stage door of the Julia. Court Theatre, where Kreisler, mastering * * * the lights in the flies, lit up, except in the himself, says that he will direct the ballet settings when the space of the entire stage is The scenic effects in this production are employed. In order to make it appear that in the opera, which ballet he has been in- remarkable because of the extreme rapidity, structed to introduce. The next scene is a person is walking off into the distance, with which they flit before the eyes of the the main platform of one of these double- in front of the curtain of the theatre, where audience. The ordinary footlights are not the rehearsal of Kreisler's opera Undine deck structures is gradually pushed toward employed, colored spot -lights taking their the rear of the stage by figures draped in is to take place. After violent words with place. Here we find amongst the innova- the director, Kreisler throws his baton down black, and hooded like members of the Ku tions, several new German spot -lights, which Klux Klan. The other movement of the and leaves the theatre. Outside he meets instead of requiring their entire body to Euphemia, who gives him her hand and says double -decked structure is also utilized, so be shifted in order to change the position that at the same time that the main platform farewell. For the second time he has lost of the spot, are fixed and stati9nary with re- all. is being moved toward the rear, the bridge gard to their carbon housings, lenses, color section is pushed laterally or toward the Part 3.-Kreisler still telling the story to screens and diaphragms. The beam from his friend, states that he has entered a thea- these machine gun -like spot -lights is thrown (Continued on page 1099) 1051 10,7,2 «;» m3 a

r. Our new submarines of the V type, which have just been laid down at the Portsmouth Navy Yard. The insert shows their engines, which are of the M. A. N. Diesel type. Those marked "El" are the main drive engines, which operate on the shafts, at the end of which are the screws which drive the vessel. Those marked E2 are engines of the same type, of less than half the power. They are used to drive the generators, which in turn charge the vessel's storage batteries for submerged cruising. The motors just aft of the generators take their power from the batteries when cruising submerged. In the event it is desirable to use the full power of all the engines on the surface, such as would be the case in fleeing from a more powerful vessel, the E2 motors can add their power to the main drive engines in the following manner: The generators are cut off from the batteries and connected directly with the motors, which in effect gives the same electric drive system as used on our larger battleships. Thus all engines are connected with the main drive shafts, giving the maximum power at the time it is needed. This mechanical feature makes these V boats the forerunners of the super - submarines of the future. The 5u'inmarine of Or o G AGER GCN0o RNGTHIEHMEIR.fl H avafl erg. STRANGE as it may seers, the full tors operated by the Diesel engines when and in Navy yards. They were assigned to powers of the submarine were not re- the vessel is cruising on the surface. the Portsmouth Navy Yard for construc- vealed in the late war. As a com- American submarines have not been so tion and their engines will be built at the merce destroyer and raider, its use successful as those of foreign makes. The Brooklyn Navy Yard. A most advanced was fully demonstrated, but its value principal reason has been the inability of design has been given them. as a scout and as a deterrent to the advance private engine builders to construct a Diesel These boats are known as the "V" class. of an enemy force was in no way revealed. motor practicable to the submarine. They will be about 335 feet long, have a The submarine of the future must be But our engine difficulties, which seem to beans of around 37 feet and draw about capable of all these duties. though each be purely those of design, are now over, as 16 feet of water when on the surface. The vessel of the future type will probably he the Navy Department is undertaking the normal surface displacement will be 2,025 designed for specifically one duty or another. manufacture of proper engines in Govern- tons and submerged the ships are reported The greatest submarine in service today is ment shops. German submarines and the as around 2.500 tons. The engines will be the French "Halbroun", formerly the Ger- latest types of the best German Navy two 2400 horse power M.A.N. Diesel mo- man "U139". She is really a large vessel Diesels were brought to this country shortly tors operating on the main drive shafts. of 1930 tons surface displacement and 2480 after the war. These engines, the famous There will be two auxiliary 850 horse power tons submerged. She is considered an ocean- M.A.N. or German Navy type were care- engines to drive the tdectric generators going cruiser. In design she is a forerun- fully measured and new ones were built which charge the storage batteries for sub- ner of the great boats which will attempt at the Brooklyn Navy Yard. They are merged cruising. And to test the theories to control the seas in time of war twenty- wonders of perfection which seem to have regarding the practicability of the electric five years hence. overcome the defects of other types. Per drive for increasing the speed of submarines She has a complete double hull, which is horse power they are lighter and more effi- these electric generators are directly con- well sub-dj,yided into many compartments. cient than any engine we have ever had nected with the motors which are in turn She is fitted like a battleship with anti - heretofore. Several submarines of the "S" connected with the main drive shafts and can rolling tanks. Her engines are the ultra- type have been re -designed with these be used for surface cruising! All the naval modern 6 cylinder, 4 cycle Diesel motors of Diesels and they have considerably bettered constructors will say regarding these boats the M.A.N. type. They are two in number their past performances, though before this is that they are expected to have speeds of and develop 3500 horse power to give the change, the "S" class had proved itself to about 21 to 22 knots, but others, very well in- vessel a speed of 17.75 knots on the surface. be the finest in our submarine service. formed, expect that these Diesel driven Having been designed for ocean cruising Last year the Navy Department received American submarines will equal the speeds as a commerce destroyer, her endurance is the initial appropriations to cover the con- of the British steam driven "K" boats-of 24 very high -18,000 tuiles at a speed of 8 struction of three of the nine "fleet" type knots! knots. submarines authorized in 1916. With these The cruising radii of these "V" boats will The submerged motive power is derived new boats it will be possible to start anew he very large, permitting them to operate from electric motors operated by great stor- our submarine history with real vessels with the battle fleet on all occasions. It is age batteries, which are charged by genera- built by Navy engineers, on Navy designs (Continued on page 1100) 1053 N w IPToce55 Cp 13/Inch and WhHe FIllharA5 f:i Y.EWHS YEAGER SCORES of experts have been work- title decorations, but in many intricate movie 16 per second. The film must actually stop ing night and day for months in the scenes. Famous Players 16 times. Each time it stops, the shutter -Lasky Studios in The new machine will do all this compli- gives an exposure. The film after perhaps California to turn out 200,000 feet of cated work at a stroke. Other systems re- a thousand or more feet have been exposed - is colored film for the new Cecil De quiring a variety of equipment have obtain- is then developed Mille motion giving a negative and the picture Adam's Rib. The Com- ed excellent results, but Mr. Taylor has positive is printed on another similar strip pany will soon be operating twelve compos- accomplished the impossible. He takes a and is finally ready to be ite automatic machines run through a each capable of pro- picture made with the ordinary camera, projector. The projector is a machine which ducing 1,000,000 feet annually. This new touches it with his magic wand, and hands jerks the film machine, in front of the light 16 times which will be one of the most intri- it to the exhibitor who may use it in any per second, so when. Dorothy Dalton hits the cate to be found in the scientific world, will proj ector. villian with a pitcher, it operate automatically is in reality a after an operator We shall new see why machinery is neces- string of pictures we see. The eye re- threads the film through it and presses the sary. If you could get into tains one image until the other is control the color labora- before us. button. It will be to the Movie tories of the Company, which few are able This is described by the physiologist as vis- World what the cotton gin is to the Textile to do, you would find the film passing ual persistence. World, and what the linotype is to the through mamr machines, each in charge of Inventors have Newspaper World. Radio appliances are used various types of ap- an operator. These experts have been work- paratus to make colored pictures. The ma- comparatively simple as compared to this ing night ar.d clay preparing new film for the jority did not go with standard equipment addition to the resources of the scien- new motion pictures. There 275 tific field. are copies and hand coloring was often used through The unit -block of twelve ma- of this film; each film is 10,000 feet long, necessity rather chines will cost $70,000.00. than choice. This is why and about 1,000 feet of colored film is used Mr. De Mille was greatly interested when Loren Taylor is the inventor of this new in each picture. In other words, 300,000 he saw the colored piece of film resulting machine which colors black and white films. f eet of colored film is necessary. The sec- from the work of Mr. Taylor. This process It is a case of necessity being the mother of tions of colored film are first made in the did not require a different camera or pro- invention, for Mr. Taylor already occu- color laboratory, then assembled and ce- jector. pies mented a place in the front row in the lead- in the proper parts in the main The details ing inventors in black and of the present process are the cinema world. The white film. guarded by the company Taylor process requires no modification but the system now of In order for one to understand the system used and which will be incorporated camera or projector, and this together with of colored into movies, an explanation is re- the composite machine can be understood the wonderful color effects made it appeals quired. The motion picture camera only from our illustration. to Mr. De Mille. records its views in black and white, and Colors are due to Scenes in the new Cecil De colored pictures as with the different wave lengths Mille pic- ordinary camera of light and each has a different ture to be released by Paramount, used are out of the question. effect on many feet of it. Not only will it be used ill Motion pictures are taken at the rate of (Continued on page 1105)

TENSION SHRINGS NEGATIVE FILM

ELECTRIC HEATING POSITIVE FILM COILS PRINTED FROM NEGATIVE

DRYER BEYELOP WASH FIX BLEACH RED YELLOW BLU

FI.1IaH ED FILM J

Q 1923 BY SCIENCE AND ONVENTION

There are several colored movie production schemes now in use which give satisfaction, both with regard but it has remained for Mr. Loren Taylor, motion to the output and the quality of pictures, a picture scientist, to evolve the process here shown, which is at once the simplest and the fastest color movie production method yet evolved. The pictures are taken with an ordinary movie camera with developing, washing and fixing, is passed through standard negative film. This film after the printing machine, and as many black and white positive films produced as are needed. These positive films are then passed through the bleaching and dyeing baths as shown, the various black and white as the film passes through the successive tone values absorbing the proper dyes baths. The film is projected in a standard machine and the films are remarkable for their clearness, there being no fringing of the colors whatever. 1054 I-The lung -fish Protopterus, is able to breathe air directly. ,s the places in which it lives often dry out. Then it buries itself in the mud and lives by respiration of the air. 2-The young of Lepidosiren, another lung -fish, have their cement organ on the under side of their head at A. They also have a strikingly amphibian characteristic in that they have large external gills. 3-A is the large adhesive cement organ borne on the front of the , head of the characin, Sarcodoces odoe. 4-The larvae of Hyperopisus bebe hung from rootlets in the nest by means of threads coming from the cement organ to keep the breathing organ free from mud and to provide them with fresh air. 5-Accra bimaculata, a fish now often kept by fanciers, also hangs up its young ones: it is a native of South America and attains a length of four inches. 6-A very peculiar fellow is Polycentropsis abbre- viata. It hangs the eggs on the under surface of some aquatic leaf. The young, recently hatched fry, hang from the leaf by means of a short thread and are further cared for, and protected, by the male. Fä.:h "[Li:Eu(4 p Young to Ripen gY E E T BADE URE often follows peculiar being feels this force. every individual at- cate if they were not protected in some paths to reach its goal. Its inven- tempts to push the other fellow against the ingenious manner. This is the reason that a tive genius is unsurpassed. Ob- wall, every species tights for its right to kind of parental care has been devised by the N\Tstacles arc surmounted with such exist. Each change and each new charac- fish inhabitants. It is in the building of ease and such apparent simplicity teristic and property inherited or variability nests that it is manifested and it is this just as if they did not exist. And then it attained, is employed in its battles. And practise which keeps the spawn and the makes no difference whether she makes a so, through the ages, each species develops young clean and also protects them front little side trip now and then to while away its progeny with better adapted weapons. disappearing into the mud. an idle hour and get out of the rut of her It is, and will remain, a war of all against Such builders and protectors of the help- daily monotonous existence ; all that she de- all, for war is here a better development, less young are the Cichlids or Chromids, sires is to accomplish her final task. Then an approach towards the perfect and ideal, native to the tropical regions of both Africa the will to live lights its lantern, as Scho- a fight for higher attainments. and South America. There are numerous penhauer has pointedly exclaimed, and it is In tropical and subtropical regions where species, and to differentiate one fròm the this will to live which finds a way, under spring with its rainy season is followed by other is an exceedingly difficult problem, for certain condition, for existence to be made long dry spells which completely destroy with slight and almost imperceptible grada- a possibility. the rivers with their tributaries and entirely tions, they blend into the various species. It The meaning of the expression of life, is, evaporate both ponds and pools, so that the is even troubldsome to distinguish the genera, everywhere in organic nature, combined with deep beds of mud and muck are baked to especially when they inhabit large, closed -in the immutable law of the variation of the hard and stone -like masses which, under the lakes where they have split into numerous individual and this variation together with powerful rays of the scorching sun, crack races but whose individual characteristics heredity form the basic principles in the into fissures and divide into crumbling are not, as yet, firmly established. It is theory of development. Otherwise new plates, the aquatic animals must develop pe- during comparatively recent times that all properties and characteristics could not have culiar structures in order to keep themselves, these many forms have been developed, and been macle a possibility, and without the as well as their progeny, alive. The bottom this change is by no means completed. law of heredity it could not have been re- of the inhabited ponds, as long as they are The parental care in some of these species tained and passed on to other generations filled with water, consists of a dust -like is very pecuilar. Acura festiva, a beautiful who not only have kept it, but perfected it muck, which, on the slightest disturbance, fish from the Amazon, deposits its eggs on still further. rises in dense clouds only to settle slowly flat surfaces which have been previously by it. The young emerge about two Although variation of the individual is a 'back again, covering the green waterplants cleaned life, the force with dirt and entering the delicate respiratory days later ; sometimes they are helped from primary characteristic of membraneous shell by the parents of self-preservation and reproduction of the organs of the animals, so that the younger the and species must be added. Every animated and more sensitive creatures would suffo- (Continued on ray(' 1137)

1055 liZecOVer-Ti% Tz-1 en Trremuire

ANEW device for salvagiig sunken These are connect: d together ti means o= a themselves actuate winches and ships has lately been the winches brough_ to the bridgelike structure. A super -structure at- in turn are connected by means of cables attention of marine enginee-s. This tacked to :his 'louses the machinery for n- to the lifting members is apparatus surrounding the tie designed by: Dr. flating an deflating the steel tacks, so as to sunken vessel, which will be C. W. Eveleth, presently de- in which (aithoigh cause then to rise or submerge, as desired scribed. Safety valves operating the power- the deta% t -ave nct been completely worked by the operator. This super -structure is ful lifting jacks, prevent out, inasmuch as they would more pressure differ with re- completely enc osed anc is fitted with the being applied to them than the tensile gard to the size cf the various pits. de- necessary safety air-valses, sc that it will strength.of pending upon the cable will stand, consequent- the ships which are t) to sal- not be sup verged accidentally The pcn- ly, the cable will not break. vaged), manly ingenious feature: toon are pre- unit in operati_ins subrerged below Although various methods have sented. To Jvercome some of the d Eiiculties all wave notion. beet, de- Ir- addition to the regu ar vised for fastening bolts and cables to the found in various other salvaging sieves, pontoons, the structure is provided w th Dr. Eveleth sides of a vessel, most of the inventors have has designed a steel frame sup- jacks atta:hed to i:. These are operated assumed that the vessel ported on either side by spherical pontoons. is lying on an even under air Jr wa=es pressure. The jacks (Continued on page 1100)

Without a doubt the greatest dream of inventors today takes the form of some machine, or else for raising device or system, for recovering the treasure in sunken ships, the ships themselves, so as :o recover the cargo as well as the hulls and engins. One of the inventor, Dr. C. W. Eveleth, is shown in latest ideas designed by a New York the above illustration. The main scheme advocated by this inventor lies in the use of a series of saddles, which are lowered individually over the ship, once it is located, and sliding large U-shaped fingers on each saddle are caused to pass under the boat, so that when all of the cables and saddles are lifted by the buoyant pontoons, the ship will be lifted also. 1056 LAKE ERIE FALLS WOULD REACH LAKE g BUFFALO BUFFALO IN 90,000 YEARS ONTARIO QUEENSTOWN

-r7 ;Me. e"fflbsiliett. .. . AT FIRST FALLS . CHANNEL 4 TT RAAWAYEOFA A"OODUTOCK ^ CUT BY FALLS $ INCHES PER YEAR IN COURSE OF 30.000 ORIGINAL NIAGARA FALLS YEARS 36 FEET HIGH TIME

PROGRESSIVE POSITIONS Of FALLS

- - 01923-By Science and Invention Geologists have attempted to calculate the age of the world, based on the time required for Niagara Palls to cut the gorge that stretches away from the present great cataract, measuring some 164 feet in height and which, according to scientiste, measured about 36 feet in height 30,000 years ago. Mr. Paul has illustrated herewith some of the pre-historic animals which no doubt inhabited the country along the Niagara River in the early days of this great waterfall. How Old Is the World ? By HARRY VAN DEMARK SCIENTIST-I believe it was Gar- Californian mountain range, just as the lat- that nobody, probably, would be willing to

rett P. Serviss-once remarked that ter appears a mere infant when its . age is hazard a guess at the number of millions it is as hard to find out the age of measured with that of the Laurentian Range of years which have since elapsed. The A the earth as it is to ascertain the of Canada, which has been worn down in Appalachians may have been magnificent age of a woman. the course of ages almost to the root. giants in their day, such as the rugged sky - In both cases, however, wrinkles tell, and The Sierra Nevadas, however, have had piercing Rockies, but time has conquered it is only the number of years that remains a double life. There was an older mountain them as it will conquer the Sierras, and now in question. Geologists assure us that the range on their site which perished, the sci- their verdured flanks and tops delight the earth is very, very old, but when we ask entists tell us ; perished before the present unalarmed eyes of railway tourists, winding them to set down its age in centuries, or range with serrated peaks and precipitous on swift trains of steel cars through the rich millennia, or periods- of millions of years, chasms was thrust upward like a young tree valleys that have fattened on the substance they shake their heads and simply reply: springing from the stump of its fallen an- of the disintegrated peaks. "Its age includes many ages, but we can- cestor. To quote from Mr. Serviss: "The glory not tell the length of any of them, not even When we study the subject, there seems of a sun is gone when it passes from light of the latest and shortest, which is the something almost lifelike in the growth of to darkness, from solar incandescence to Age of Man." mountains; they do not attain their maxi- planetary opacity." Still, some geologists are not averse to mum stature all at a leap. The first great Likewise, the splendor of life for a moun- guessing on this subject, occasionally, and uplift of the Sierras, the geologist thinks, tain departs when it sinks from white to some of these guesses are very interesting. elevated the range about 2,500 feet. Even green, and from the abode of snow to the One California geologist did not attempt to that took time, while the giant pressures levels of grass and verdure. fix the whole age of . the earth, but only were at work. Vast periods also elapsed Dr. R. Lotze, in his new work Jahres- that of the wrinkle on its face known as the while the growing mountains swelled up- zahlen der Erdgeschichte (Yearly Almanac Sierra. Nevada Mountains. Those moun- ward to their culniination of fourteen or of the Earth's Transformations), says: tains, he says, are about three million years fifteen thousand feet. Perhaps they are "We will now turn to North America, old. still growing, though such growth would the third greatest source and the third He reaches this conclusion by a study of be inappreciable by the- naked eye. great scene of glacial activity, which, like the changes that have taken place on the Age has its common marks everywhere. North Europe, was covered under a huge face of the earth in California since the Just as an old man stoops, shrinks in sta- mass of inland ice. As the ice disappeared. Sierra Nevada Range began to assume its ture, becomes round-shouldered, so a time- which must have occurred a, the same present form From the observed rates of worn mountain loses its aspiring peaks, time as in Europe, little by little the region erosion, and other natural processes affect- smooths down its jagged outlines, rounds of the Great Lakes of the present day became ing the rocks, he deduces the number of off its steep slopes, sinking lower, and lower free of ice; their water had to seek the sea. years that have elapsed since the commence- under constant wear of the elements, until Between the Erie and the lower level of Lake ment of the changes. only a line of green -carpeted hills remains Ontario, a waterfall formed, and poured All of which recalls the method by which to mark the place where once tremendous over the intervening declivity. This was the geologists have determined the time required summits rose into the region of perpetual beginning of Niagara Falls. By the wear- for Niagara Falls to carve out the gorge snow and flashed back the sunshine from a ing action of the falling water, the weaker that stretches away from the foot of the crown of glaciers. strata at the bottom of the falls were washed great cataract-though with no great ac- It seems relatively an easy task 'to cal- away, so that the upper harder strata had curacy or agreement of estimates. culate the age of a mountain range which, to fall. As a matter of fact, the data for such a like the Sierra Nevadas, had a new birth "In this way the waterfall cut its way con- calculation appear to be much more definite at the beginning of quarternary time, the stantly backwards into the rocky layer, and and .certain in the case of Niagara latest period in the.geological history of our even today it is working its way back to- than in that of the Sierra Nevadas, and yet planet. It would be far more difficult to ward Lake Erie. In the course of time, it for the work of the Falls the estimates of apply the measuring tape of the centuries has cut away a channel 11.3 kilometers long time vary from twelve thousand to thirty- to the great Appalachian Range, which lies or about 6.8 miles, which in its various six thousand years. At the most, however, lust beyond our Atlantic seaboard. parts shows clearly the history of its pro- it will be observed that Niagara is very The Appalachians date back to the remote duction. Originally the falls were only 11 youthful, when compared with the great carboniferous age, which ended so long ago (Continued on page 1123) 1057 By H. G. WELLS

Il was on the first day of the new year become erratic. Ogilvy had already called Neptune, nor outside the astronomical pro- that the announcement was made, al- attention to a suspected retardation in its fession did the subsequent discovery of a most simultaneously from three ob-. velocity in December. Such a piece of news faint remote speck of light in the region of servatories, that the motion of the was scarcely calculated to interest a world the perturbed planet cause any great excite- planet Neptune, the outermost of all the greater portion of whose inhabitants ment. the planets that wheeled about the sun, hid were unaware-of the existence of the planet Scientific people, however, found the in - 1058 ® 1923 by Hclenee & Invention swayed and rumbled with the earthquake shocks. . . Above were the lava, hot gases, and ash, and below the seething floods, and the whole earth ' melting and pouring down by ten million deepening converging channels upon the plains Soon the immemorial snows of Tibet and the Himalayas were waters around the of Burma and Hindustan. The tangled summits of the India,i jungles were aflame in a thousand places, and below the harrying stems were dark objects that struggled feebly and reflected the blood red tongues of fire. . near- telligence remarkable enough, even before system. The sun with its specks of planets, the distance to be traversed before the its dust of planetoids, and its impalpable est of the stars is attained. And, saving a it became known that the new body was the rapidly growipg larger and brighter, that its comets swims in a vacant immensity that al- few comets, more unsubstantial than motion was quite different from the orderly most defeats the imagination. Beyond the thinnest flame, no natter had ever to human progress of the planets and that the deflec- orbit of Neptune there is space, vacant so knowledge crossed this gulf of space, until tion of Neptune and its satellite was becom- far as human observation has penetrated, early in the twent eth century this strange ing now of an unprecedented kind. without warmth or light or sound, blank wanderer appeared. Few people without a training in science emptiness, for twenty billion times a mil- A vast mass of matter it was, bulky, can realize the huge isolation of the solar lion miles. That is the smallest estimate of (Continued on page 1ï17) 1059 ANCIENT MECHANLICS

An example of tho compound lever, as given in the strange old treatise.

An attempt at perpetual motion. The ball, C, Is supposed to be drawn up by the magnet. A, to return to the bottom and be drawn up again repeatedly.

The Bishop's own conception of perpetual motion, based en Archimedes' screw, only It did net work.

Mooing the world and weighing the. word. The diadrams Illustrate Archimedes' boast about the lever

The Bishop's train of wheels, a trivial fern raising a great weight.

Uprooting a tree by the human breath. What about the friction? The attainment of the velocity of the celes- tial bodies by a train of gear wheema.

A willig chariot which' we, tined ea the Helland beaches

stikesmowo.d.i'

A catapult discharging 1ledt of arrows; Bishop Wilkins Idea of an Improved sail- A ballistic for throwing great stsnes, Some- a maehinegun of former beneratiens, ing chariot. times human heads or betties were used u Projectiles.

1060 e Bish(ep Kthernatice ;Xn Il T. O9COM OR G1S4©AgV ibp Ph. LL. De

READERS of the amiable Evel whom he speaks quite often, he illustrates air, so that they burned. He tells wonderful diary, and those who have perused the proposition by which the sage of Syra- stories of the Turkish archers; of their ar- the less amiable Pepy's diary, will cuse said he could move the world on the rows penetrating thick wood and iron plates. have encountered several tintes the end of a lever, and shows the world on a He quotes an earlier author, C. Mersenns, name of Bishop John Wilkins, who steelyard about to be weighed. So much telling of a wonderful air gun, which at a was born in 1640, and died in 1672, for the lever. distance of twenty-four paces would flatten and attaining promotion in the church Now we come to his trains of wheels. a leaden bullet against a plate of iron, and he of England, eventually became Bishop These he calculates out on the basis of the cites also a curious old theory, that arrows of Chester. Besides his activities in the large gear being ten times the diameter of and bullets had their greatest penetrating line of his religion, he was greatly inter- the small. So again he goes down the line. force at a good distance from the muzzle of ested in natural science, and he with Evelyn multiplying by ten, and shows that a man the gun, which of course is absolutely false, figures among the founders of the Royal by the least force exercised upon a handle, although he takes it as matter of general Society of Great Britain, one of the leading can raise a great weight. And he goes fur- knowledge. scientific societies of the world. When twen- ther than this. With a very large train of Two other things greatly interested our ty-four years old, he published an odd little wheels, he shows a man pulling a tree up by Bishop, flying and the submarine. He believed book which now is a great curiosity, kept the roots, by simply blowing against a wind- very properly that if an aviator got high in the Reserve Department of the New York mill which turns the gears. Going to the enough in space the earth's attraction would Public Library, on the subject of the moon. other end of things, he shows how by plac- cease, which certainly would facilitate the He claimed that there was every reason to ing a man at the other end, and turning a flying process. He says, "flying so generally believe that the moon was inhabited, and handle, a great velocity can be imported to derided-being esteemed only as the dreams even seemed to think that there was a pos- the vane at the top of this gearing, and he of a melancholy and distempered fancy". sibility of mankind traveling to the moon. figures out that at a thousand turns per hour This makes curious reading for us, when we This little hook gave him considerable cele- at the man's end, the vane at the top could can remember how Professor Langley failed brity. He also discussed the topic as to be macle to move as regards its extremities to receive adequate or even serious support in whether the earth was a planet. But when with the speed of the celestial bodies. his pioneer work in aviation. Our Bishop we get to another of his works, "Mathe- He describes a sailing chariot shown here, refers also to Burton who in his famous matical Magick," also a very small book, but which was used on the beaches of Holland. "Anatomy of Melancholy", has stated: illustrated with a number of engravings, we He says it ran from Sceveling to Puttem, a "Some new tangled wit ('tis his cynical get at quite an interesting lot of material. distance of over forty-two miles, in two phrase) will sometime or other find out this On the opposite page we have reproduced hours, which he regards as an enormous art." in this trea- speed, making a running man seem to move some of the ilustrations shown Blackwood's in which he investigates many things, i:ackwards. He made a proposal for a A writer in Magazine of tise, 1917, is little hard on the Bishop. including perpetual motion, the mechanical chariot to be operated by a wind mill, and July, a catapults, ballistae, we a reproduction of his design for this. He is inclined to make fun of his long rows powers, sailing chariots, give he his we specially name here, be- He discusses the weapons of the ancients, of ciphers, which had to use to express which subjects multiplication of force by his gear wheels. cause the ilustrations appear opposite. and those of his own era, and says the cata- pult, an engraving of which from his book So when Bishop Wilkins begins to describe One attempt at perpetual motion is shown, he is to draw is reproduced on the opposite page, was used the possibility of submarine work, tells in which a magnetized ball supposed of nothing he himself has done, but has to another free iron ball up an inclined plane, to shoot arrows sometimes in various direc- its it is tions, sometimes all at one point, and shows go hack to the work of Cornelius Drebbel, and when the latter reaches top in sixteenth century in Holland, a hole therein, the how by releasing the elastic board, a flock horn the supposed to fall through who is said to have gone under water in magnet being unable to keep it up any longer, of arrows could be sent against the enemy. foot of the inclined The ballista he says, on the other hand, was the Thames, from Westminster to Green- and to return to the wich. He is said to have purified the air by plane, to be drawn up again by the magnet. used for throwing stones, and gives us a crude attempt and construction of that implement, which is a liquid, surmised to have been cream of This of course is a very lime, and the Bishop describes how by a sort a page he des- shown here in reproduction also. This he absolutely futile. In later of leather bag, the submarine could be en- cribes an Archimedes hydraulic screw, which regards as a very wonderful affair. He and says that the biggest shot fired by modern tered under water or a person could leave. by turning draws water up to its top, The bag being fastened tightly in advance of which water is discharged into water wheels, guns, in Europe at least, weighs 64 pounds, screw. He while the ballista could throw mill stones the person first, it would then be tied tightly which are supposed to turn the behind him, and finally he says, and felt and tomb stones, weighing up to 360 pounds, by releasing the got quite excited about this fastening he could emerge, and swim like calling out with Archimedes, "I have and Archimedes is credited with discharging outer I have found it!" But, he says, 1200 pound stones. He says that the com- to the surface. Similar bags were to be found it! for helical when he came to look into it, he found that batants used sometimes to put men's heads used for the oars, the propeller it too would not work. or bodies into the ballista and discharge these had to wait nearly three centuries for its in- We now come to some of his mechani- into the town they were besieging. vention. cal powers. He shows a set of levers ar- He now comes to the Turks, and says that On one of the copies of Mathematical ranged in quite a curious zig -zag fashion, they had a cannon which would fire a 1200 Magick in the New York Public Library with each one of the power arms ten times pound projectile and it took 150 yoke of some oldtime reader has inscribed his views as long as the resistance arm. We can go oxen to draw it about. Referring to ar- concerning the Bishop's gears and trains. right down the line and find an enormous in- rows, he has some curious stories. He says The faded inscription is only partly legible crease, and this is what interested him. that the arrows from the catapult were reading "Good Bishop pray allow some . . Returning now to his friend, Archimedes, of sometimes ignited from the friction of the . . . for friction." The Eveir©ChangIlng Gulf Sereaun

It has been reported by mariners recently An authority, Commander Brown, head of Three factors influence the course of the that the Gulf Stream was 30 miles nearer the Navy Hydrographie Bureau of Boston, Gulf Stream. The first and most important shore than it was 10 months ago. This im- says that the Gulf Stream does not touch of these is the high declination of the moon. mediately started up the weather prophets, New England. It heads out to sea below The second cause would be a high barometer who now claim that the recent hot spell Nantucket, and only affects people from Bos- in the north Atlantic and a low barometer in experienced along the east coast, and espe- ton when they go fishing off the Grand the south. The combination changes the cially in New England. can be blamed upon Banks. What influences the New England course of the stream by reducing its rate the nearness of the gulf current. coast, the commander states, is a branch of from two knots per hour to one or one and The French scientists claim that the the Labrador current swinging counter- a half knots per hour. The trade winds off United States are creating a tropical New clockwise from Newfoundland. Accord- the south of Cuba would be a result of this. England and making England and France ingly, if the Gulf Stream does change, it The third cause of a change in the stream frigid. The trouble, according to the French- could have small effect on New England. would be an unusual storm. not had men, lies in an innocent little railroad, built Furthermore, western Europe has The Navy Department, having examined several years ago from Florida out to the weather recently that could be laid to a all the available facts, believes that the Florida Keys. It was built on a trestle with change in the stream. England had a rainy Frenchmen's theories are unfounded. loopholes left between the islands where - summer, which is the normal result of ever there was an appreciable current. the Gulf Stream being right on the job. Contributed by J. WARREN BARNABY. 1061 'z

GLASS S INSULATOR

CONNECTING AR WIRE i' GLASS METAL f2/923 ByJ'c/Pme ¢ %neenCo,z.

The Sleep Eliminator as installed in a modern newspaper office. Mr. Gernsback, in his article, suggests, in order to eliminate sleep, to remove the cause. The cause of sleep is increased blood pressure, also certain changes in nerve cells after the body has performed a certain amount of work during the day. These causes are removed by D'Arsonval currents, which are set up in a huge electric coil, strung along the walls of the office as seen. These cur- rents, as is well known, reduce the blood pressure. The oxygen, as well as the ozone with which the air is charged in small quantities helps to rejuv- enate the system. A secondary electrical system gives the nerves certain rhythmic shocks, almost imperceptible to the subject. These are used to stimulate the nerve cells that have become sluggish. It is thought that by these means sleep can and will be eliminated entirely.

i3y 111. GERNSBACäSl1 Member American Physical Society COMING INVENTIONS NO. 8 The Histological theory has to do with the other ancestors simply lay down and formed ONE of the most ancient and uni- nature of the nerve cell, because microscopic the habit of sleeping until the sun came up versally -known phase, not only of examination has shown conclusively that again. That this is a true statement is best human existence, but of almost such nerve cells have different chemical prop- próved by the fact that as soon as artificial the entire animal world, is sleep. erties when the body is in a waking or in a lighting appeared, the human race no longer It is such a habit with us that we sleeping or fatigued conditon. needed as much sleep as did our cave an- never give it the slightest thought, and we do Other outstanding phenomena, character- cestors. Even as recently as 500 years ago, not bother our heads much about it, unless istic of actual sleep, are full relaxation of people went to sleep at sundown and got up we suffer from insomnia or if important nearly all the muscles of the body; slow when the sun rose. That means an average of ten to twelve hours sleep. The , work keeps us up, perforce, when we are and rhythmic, as well as deep breathing; a modern trying to fight off sleep. slow and weak pulse, and considerably les- human being gets along comfortably with from six to'eight hours, as his M But what is sleep itself? No one knows sened arterial pressure. artificial light exactly. There are many theories of sleep keeps him awake, and the less he works But is sleep really necessary, and could physically the less sleep he needs. today, the best known being the following: man or animal do without it? The answer the Chemical, the Circulatory, and the .His- must be in the affirmative, once we discover Naturally this statement does not hold true tological. just the exact reasons why sleep takes place. of a laborer or a man who performs great The Chemical theory mainly has to do We find, for instance, that protozoa and physical exertions during the waking hours. with auto-intoxication. This theory is based other simple forms of life seem to dispense Such a man becomes really fatigued and his upon the fact that certain products of de- with sleep, without any trouble. Many fish, blood pressure during the night time must composition of living substances influence for instance, do not sleep, and while their be brought to normal, and his nerve cells the continuance of cell activity, but recent activities may not be the same must be regenerated once more. researches at all time, in the bacteriological laboratory they do not seem to know what sleep, as we But we are safe in saying that if the have proved that while the body is working know it, really is. human race continues as it does now with during the day's activites certain ptomaines In other words, sleep is a habit formed by artificial light during the entire night, a are formed in the human system more rapid- time will come, in 10,000 perhaps ly human beings, mainly due to astronomical or 50,000 than they can be oxidized and eliminated. years, when sleep will be required no longer. It is maintained. reasons. If the sun had been shining upon that while we sleep, such Edison, a few years poisons gradually become oxidized and are the earth constantly we probably wduld not ago, made some very thus know now what sleep is. For one part of striking observations when it was necessary removed from the blood. to work literally The Circulatory theory has to the day we have light; for the other part, day and night in his labora- do with tory. He selected a number congestion of the blood vessels. It is a darkness. After sundown it is no longer of young men theory no longer accepted by scientists. possible to see, and the caveman and our (Continued on ¡sage 1114) 1062 '1(mü0zzpriz00ning Q ocà othprr000ng

B ISMAR GHNSIIIERGfl 5cofl Chesirh.

THERE are four important textile effects of the rubberizing process, and still ing solutions into the fine pores of the textile fibers, cotton, wool, silk and linen. gives a fabric which is ventilating, which fibers. The process was perfected and dur- While they differ in origin, struc- allows air to pass through it, while re- ing the war it performed signal service in ture and properties, they all possess sisting perfectly the passage of water. The waterproofing the uniforms of the Ameri- one characteristic in common, albeit electric current causes the chemicals, that can and Canadian air forces. At the pres- in different degrees, and that is permeability are used in the process, to penetrate into ent time the process is being operated on an to moisture. Water will penetrate through the internal structure of the fibers, so that industrial scale in the plant at Cranston, their structure and naturally through the the waterproofing substance fills the fine, R. I., a part of the old and historical Crans- fabrics woven from them. This funda- hair -like passa es in them. In this way a ton Print Works, where it is possible to mental property of the fibers gives rise to a comparatively permanent waterproofing ef- waterproof goods at the rate of three mil- definite disadvantage in the fabrics them- fect is attained. In contradistinction to the lion yards of cloth a month. selves. The wearer cannot keep dry in chemical process, described above, the A specially designed machine is used to water -pervious garments when exposed to waterproofing does not consist of a mere accomplish the waterproofing. The machine rain; non -waterproof fabrics will not keep film of substance over the exterior of the contains either two or four sets of elec- out the rain, when used as protective cover- fibers, which can be easily washed off, but trodes, the two -set machine being used for ings, as in tarpaulins, in tents, etc. of a thorough impregnation and filling of silk and wool, the four -set machine for cot- Ever since this disadvantage in the fabrics their entire structure. Such waterproofing ton and linen. The cloth first passes through was first recognized, attempts have been will successfully resist many washings, and a bath of sodium oleate, which is a solution made to overcome it. It was found that not only that but dry cleaning as well, to of soluble soap. Then it passes between the when the textile cloth was impregnated with which the chemically waterproofed fabrics various sets of vertical electrodes. At that India rubber, the product was waterproof, are not resistat.t at . time it is impregnated with a solution of but unfortunately it became air -proof as It is very interesting to trace the his- the chemical, acetate of alumina, whils `he well. Those of us, who have worn rubber tory of electrical waterproofing of textiles, current flows from anode to carnode raincoats on a warm day, know how uncom- for in its origin it is closely and directly through the chemical solution and the cloth. fortable they can be. It was also discovered allied to the electrical industry and to one Chemical and electrochemical reaction takes that chemicals could be used in producing of Edison's inventions, the chalk telephone place with the formation of an insoluble a water -proofing effect in fabrics. This con- receiver. The inventor of the waterproofing aluminum soap within the capillary passages sisted essentially in depositing an insoluble process, Mr. Alfred O. Tate, who has been of the fibers and on the surface as well. soap on the fibers, by first impregnating awarded the Howard N. Potts Gold Medal After the cloth has passed between all the them with soluble soap solution and then for his work by the Franklin Institute of sets of electrodes, it goes over a series of precipitating, that is, throwing down the in- Philadelphia, was originally connected with drying cylinders, heated with steam, so soluble soap by acting on the impregnated Edison in the very early days of the electrical that it is perfectly dry on emerging from cloth with a solution of a proper chemical. industry. He worked on the chalk telephone the waterproofing machine. Such waterproofing, commonly known as receiver and noted the strong action of the One of the important features of the chemical waterproofing, is merely a super- process is its applicability to all sorts of electric current upon an electrolyte which fabrics. Such heavy materials as sailcloth, ficial treatment, for the film of waterproof- filled the pores of a chalk cylinder, pro- ing material lies on the surface of fibers overcoatings, awning goods, tent -cloths, etc., only and is soon either worn off or washed ducing thereby sound effects in a diaphragm. as well as thin fabrics, such as sheer silks, away. 'Years later, when confronted with the water- ordinary muslin, etc., pile fabrics, such as The process of waterproofing textile fa- proofing problem, he recognized that here plush mohair, velvets, etc., and even such brics with the aid of the electric curre_it was a task which the electric current could special cloths as large meshed bobinette can combines all the advantageous waterproofing solve by forcing or carrying the waterproof - (Continued on page 1107)

-.SQUEEZING ROLLS SOLUTION OF ACETATE OF ALUMINA

ff ELECTRODES REMOVES THE STARCH 1° I ELECTCO-CHEMICAL' OLEATE OF SODA J/ ACTION PILED UP TO REMAIN BATH IMPREGNATION OVERNIGHT

FINISHED DRYING CLOTH ROLLED UP

THENCE TO

STEAM -HEATED CYLINDERS

CALENDERS TO APPLY FINISH

The simplified diagram -chart above shows the important progressive stages followed in the latest method. of waterproofing and mothproofing cloth by electricity. Rubber raincoats, for example, are very uncomfortable in warm weather or at any time when it is not cold, as they will not pass air. By the new methods here shown and described by Mr. Ginsberg, an authority on this particular subject, various cloths can be waterproofed and these cloths will, after waterproofing, successfully resist many washings and will even stand dry cleaning, which treatment the ordinary chemically water- proofed fabrics will not stand. 1063 TO RADIATOR

HARD VULCANIZED TUBE OUTER SHELL

In Fig. 1 is shown a device which allows the driver to keep an accurate record of all gas and oil bought in the course of a month. The metal shell is cut away to disclose the cardboard disc, upon the front of which are spaces for dates and amount of gasoline and oil bought, while on the back are spaces for total records at the end of the month. A combination stop signal, tail light, and license bracket, is shown in Fig. 2. The stop sign disap- pears in back of the license plate when not in use. A steel tube containing compressed air is shown in Fig. 3. By means of a gauge just above the valve handle, a tire may be inflated to any desired pressure. In Fig. 4 is shown a device for vaporizing low grade fueL The heavy fuel collects in the basin marked 1, and is held there until heated by the exhaust and vaporized. The fan shaped blales, 2, assist in vaporizing the fuel. A wind -shield wiper which cleans the entire upper surface of the wind -shield, is shown in Fig. 5. This is actuated by an electric motor connected to the starting battery. In Fig. 6 is shown a new type of air cooled motor, employing copper fins electrically welded to the cylinders to increase heat radiation. Fig. 7 shows a wind -shield wiper actuated by the suction of the intake or of the vacuum tank. It can be locked up out of the range of vision when not in use. A thermostat control for the flow of water from the radiator to the motor is shown in Fig. 8. A spark plug with self-cleaning points is shown in Fig. 9. A draft of air actuated by the suction of the motor keeps the points free from carbon. Fig. 10 shows a small resistance coil inserted in the intake. manifold, which is heated by means of the starting battery, and assists greatly in vaporizing the fueL An automatic "low gas" signal, which is fastened on the gasoline tank cap, is shown in Fig. 11. The "super -wheel" is shown in Fig. 12. The spokes consist of heavy spiral springs which absorb a considerable amount of road shock, and within the shoe is a soft rubber insert which protects the tube from punctures. ®veRti s at w York Auto ohow. THE second week in January was a month, and the speedometer reading on the obtained within the tire, a whistle blows, momentous one for automobile first day of the month. He now puts the attracting your attention thereto. It is pos- owners and drivers in and around disc into the device, and turns the knurled sible to operate this device even at night New York City. For the entire ring until the day of the month appears in without the use of any lights without en- week there was a display of all the opening. Then when he buys gasoline dangering the tires by over -inflation. Jacks kinds of automobile accessories, as well as and oil he jots down the amount in the are also manufactured by this company complete cars at the Grand Central Palace, spaces provided, and at the end of the which work by compressed air supplied by and another smaller, but just as interesting month has an accurate record of all pur- these bottles. They make them in several show, at Madison Square Garden. chases. From this and his speedometer sizes, the largest one capable of lifting a Do you know just how far your car goes readings he can figure out whether or not heavy truck. These compressed air bottles per gallon of gasoline, and per quart of his car is running as it should. The card are exchangeable for full ones when ex- oil? This is a question that very few can be then exchanged for another one for hausted in the same way that the old acety- drivers can answer accurately, as they have the next month. lene gas containers formerly used in auto- never taken the trouble to keep an accurate A unique stop sign which combines a tail mobiles could be exchanged. record. However, if he uses one of the de- light, license bracket, and signalling device Carbon dioxide gas is also put up in these vices shown in Fig. 1, he will be able to very is shown in Fig. 2. This is electro -magnetic- bottles for use in extinguishing fires on easily keep an accurate record of these ally operated, either from a button on the automobiles, and the gas can also be used figures. Essentially this device is a round wheel, or a switch on the brake, and a large for making carbonated liquids by forcing a metal case which clamps on the steering red and white stop sign appears when quantity of the gas through the liquid. A wheel, and which has a removable cover. needed. A separate signal light is not used, refrigerating container can be used in con- Within this case is contained a replaceable as the white light emanating from the side nection with this carbon dioxide bottle for cardboard disc, which may be rotated from of the tail light illuminates the stop sign keeping foods and liquids at a low tempera- the outside of the case by means of a when it is raised. This sign swings up side- ture. These bottles contain gases at a pres- knurled ring. As may be seen one side of ways from inside a thin sheet metal con- sure of 1000 pounds, but the danger of an the disc has several concentric circles drawn tainer, on the outside of which is bolted the explosion is done away with by having the thereon, and a number of figures around the license plate. The storage battery in the car containers capable of withstanding ten times outside edge corresponding with the days is used as the source of current for actuat- that pressure. The bottles are inspected of the month. Between the first and last ing the magnets. and tested by government officials. figures there is a space in which the name At last the nuisance of a hand pump is Very often with poor grades of gasoline, of the month may be written. On the op- eliminated. All you have to do now is it is practically impossible to start the car in posite side are spaces provided for the carry a small bottle of compressed air as cool or cold weather, because of the great speedometer readings on the first and last shown in Fig. 3 in the tool compartment of amount of liquid gasoline caught in the man- day of the month, and for the total amount your car, and when a tire blows out, you ifold. This of gasoline change trouble is done away with and oil used. Several discs are it and inflate the tire from this bot- by the apparatus shown in Fig. supplied with each device for various tle. An automatic gauge is arranged on the 4. Here months. The driver inserts the name of the bottle so that when the required pressure is (Continued ois page 1101) 1064 TO e n e By CLEMENT F EZANDIt

comes my task. I am to fertilize the ova (AUTHOR'S NOTE.-At the present moment 14®®$he Secret ®g culture fluid giving No. and incubate them in a suitable the French and the Germans are con- until the baby -whales reach the the construction of in glass jars siderable attention to the M®t®r].t_.ss at which they would normally be "gliders". At 1Vasserkiippe in Germany, stage Herr Hent.,en recently made a record flight Air e lane born." of over three hours duration in a motorless "Good gracious!" airplane. He traveled a distance of 25 kilo- "What!" "And that's not all, Silas. Whales, as are mammals-that is to meters and reached an altitude of 360 meters. Whales-The order is some- you probably know, records. The "Yes-Sperm say, the mother -whale feeds her young on The French have made similar what unusual, isn't it, even though it is only of such machines is a very bright her own milk. So to feed these hundred future baby -whales that are wanted?" they one. In the following store 1 give a sug- thousand prospective baby whales until do you mean?" I am gestion for a combined balloon and glider- "What in the world are able to take care of themselves, you of con- a combination that seems feasible, and that Doctor Hackeusaw smiled. "I thought to send to Japan several shiploads would, under certain circumstances, possess would be astonished, Silas," said he, "but densed milk! What do you think of that certain advantages over both the airplane the explanation is really a simple one. You for an order?" and the balloon, as well as over the simple may perhaps know that the Sea of Japan "It heats anything I ever heard of. Are clays one of the finest hunting glider.) . was in former you going to accept?" or cachalot as grounds for the sperm -whale know yet. Perhaps I'll take a new on These whales could be found "I don't AVE you got anything it is called. run over and get things started for them. hand, today, doctor?" asked Silas there in large schools. With modern meth- I !raven't much at hand at present except my Rockett, as he entered the labora- ods of whaling, however, these valuable going to test out one of the motorless airplane that I'm 11 tory and dropped into a vacant animals are becoming extinct, and it proves successful I to re- this afternoon. If chair. Oriental governments has decided with me and use it for with whales. Hence may take it along "Nothing much, Silas," returned Doctor stock the Japan Sea whaling purposes." at pres- this letter. This government wishes me to Hackensaw-"Things arc quiet just "A motorless airplane? You never men- a letter, though, that may in- go to Japan for a few months. They agree ent. Here's supply of tioned that before. Do you mean a glider?" terest you. It's from a party that wants me to furnish me with a sufficient with a hundred thousand living egg -cells and sperm -cells taken from to furnish them Then (Continued on page 1124) sperm whales." the cachalots killed by their whalers.

© 1923 by Science & Invention land most anywhere, because my ascent is prac- none of the noise and fuss here of an ordinary airplane. . I can rise and "'You see, Silas, we have wish, thus eliminating two of the greatest dangers of the airplane. For tically vertical. Then, too, the start and the landing are effected as slowly as I from here!' of hovering is very useful. See how easy it would be to drop a bomb on one of New York's skyscrapers war purposes, too, this faculty truth of his companion's remarks." . . Silas looked down and was forced to admit the 1065

Fig. 1 shows a sectional view through iron tub flask together with sand, two gas vent holes and pouring iron being poured into the latter. Fig. 2 hole in center, with large ladle of molten shows tub upside down with one operative using file, while second grind down and finish rough iron tub. 3 man uses flexible shaft emery wheel to before Fig. shows section of pickling solution vat with tub being lowered into it enamelling. Fig. 4 shows view of gas heated enamelling ovens with for purpose of cleaning thoroughly electric pyrometers, etc. A compressed air cylinders for opening and closing oven doors, together with man is shown operating an air valve, also another man with leather apron Fig. 5 shows red hot tub removed from oven, and one operative sifting and large boom about to place iron tub in oven. enamel powder over the tub. Fig. 6 shows tub being replaced to fuse and bake on enamel. in oven so as Now nemeLe. fron PSU:b5 Azae e de y WHHFHELD GECOR ONE of the commonest things that castings are made, the traveling cranes carry with gas and compressed air, or else with we see and use every day is the large clay -lined buckets of molten iron white enameled iron down fuel oil fed under pressure, the insides of wash basin, along the foundry, and any small serving the ovens being -brick, and also bath -tub. We buy the ladles lined with tile or fire used by the men are filled from these. with the flame burners placed around the iron tub or basin, get our plumber After to install it. and promptly forget an hour or so when the castings outside, but protected by an outer wall to all about have set, and the conserve the it, except when we want to use it. It is an temperature has decreased heat. When the door of one interesting story considerably, which slow cooling is adopted of these ovens is raised by a compressed which has not been told to prevent air cylinder heretofore, describing the process of cast- too quick a temperature change and plunger arrangement, as ing these large iron and possible cracks occurring in the cast- shown in the drawing, (the valve controlling vessels and enameling ing, the molding them in huge ovens, which resemble minia- flasks are knocked apart, the air pipe line being placed quite a distance ture infernos. the sand cleaned out, and the castings put from the doors, due to the terrific heat,) on small trucks, the inside In the accompanying and run to the cleaning of the furnace when fully heated illustration the suc- room. looks like a duplicate of Dante's inferno. cessive stages followed in making an iron The leather-aproned bath -tub Fig. 2 shows mechanics busy cleaning men who place the tubs are shown. The same operations the as they come from the finishing hold true for wash basins rough cast tub. Coarse rasp files are room in the and other vessels used for some furnaces to heat them up to red heat, and containers of this type. There are some of the work, while most of which the rough projections, edges, etc., takes about eight to ten minutes usually, smaller water containers of the enameled are fin- pick up type, ished off smooth with a small emery wheel the tub from the truck with a long which are made from pressed steel bar containing a U-shaped '1 driven by a flexible shaft, from a motor iron cradle at and not from cast iron, but the latter, older or one end, and process still holds line shaft. In this way the mechanic can a double handle on the other. the field to a large extent. take hold This bar is suspended from 1 of the flexible shaft and run the its center by Fig. shows a sectional view through a chain or cable the iron flask rapidly revolving emery wheel over any part from the ceiling. This bar or frame in the foundry of the is about twenty feet long and which is filled with molder's sand, tub he desires. The inside and outer in this way which surface of the roll rim the tub can be placed in the oven or removed has been prepared with a wooden or iron receives special at- without tention in finishing, as this must be very undue discomfort from the heat. pattern of the tub, so that a hollow space is. smooth left in the sand into in order to give a perfect enameled Electric pyrometers or temperature in- which the molten iron finish. dicators are fitted when poured, will flow and form the to the ovens in most mod- tub. The iron tub is next thoroughly ern baking rooms, so that the temperature Gas vent holes are made in the top of cleansed of the the mold as well as one or more of all dust and iron particles by treating it oven can be regulated to the proper pouring degree. When the tub holes, into which the molten iron is poured to a pickling bath. This may be an acid or is thought to have from large a caustic soda solution; been heated sufficiently, that is, to a red a ladle. These large ladles nec- it thoroughly heat, the essary to hold sufficient cleanses the iron surface, and prepares it door is opened by one of the men molten iron, for who takes care pouring such a large object as a -tub, for the enameling process. of this part of the job, and bath the handler grasps his are handled by two men, a handle extend- The tub then goes to the long tong bar and enameling room. places a U-shaped crutch under the tub rim, ing from either side of the ladle for several See Fig. 4. Here we find a line feet. In of great and pushing down and walking backward, the foundries where these .large enameling ovens, which are heated either (Continued on page 1098) 1066 1-A gauge flat within a millionth of an inch. 2-Curved bands show that the near and far edges are lower than the middle of the gauge. 3-Com- paring thicknesses of two gauges. The gauge at the left is shorter by a half band, or five millionths of an inch. 4-Measuring the diameter of a plug. 5-The zrrangement of the cardboard templet for measuring the diameter of a ball bearing is here illustrated. 6-The two balls here shown are identical, as is evidenced by the parallel lines or light bands. In the upper left hand corner the method of making measurements is demonstrated.

AITHOUGH measurements correct to water containing kerosene. But interference ber of bands which are seen, indicate the within a distance of a millionth of of light waves resulting between two plates steepness of the wedge of air occurring be- an inch are possible, very few indi- when viewed in monochromatic light, or tween the optical flat and the gauge. If viduals understand exactly how light of one color, gives a series of alter- these bands are seen to be parallel, then we such measurements are made. Sim- nate light and 'dark spaces rather than the are positive that the gauge is accurately plicity is the watchword. Such a thing does colors seen in daylight. flat. For the purpose of measuring the not seem possible in such accurate measure- The average wave length of a beam of gauge which is not perfect, the optical flat is ments, yet all the instruments required are light is approximately two one -hundred - placed upon the gauge, whereupon a series two so-called glass flats whose surfaces are thousandths of an inch, or twenty millionths of curved lines would be noticed. By re- perfect planes, and a fixed or known gauge. of an inch, but the light and dark spaces ferring to the diagram, the method of indi- The glass flats are not lenses; they do not noted, result from interference of light cating the amount of curvature of the sur- magnify, they merely present a perfectly waves. It is evident therefore, that the face may readily be seen. Consequently, our smooth true surface of a plane. The gauge bands which are a noticeable distance apart, second measurement is easily found, that is is of known dimensions, accurately ground. are not light waves themselves, but respec- to say, a person can instantly tell that the If two pieces of flat glass are placed to- tively indicate places where interference and surface of a gauge is not flat, and by simply gether, so that the film of air between the reinforcement of the waves occur between projecting a line from one edge of the cur- plates is very thin, a series of colored inter- the two surfaces at one-half wave length in- vature of a dark band to the opposite end, ference fringes or bands will be seen if tervals. Therefore, each dark band shows a add dividing the distance between the two viewed in the daylight. This effect is distance not of twenty millionths of an inch, interference bands into tenths, we are able often visible when washing windows with hut ten millionths of an inch, and the num- (Continued on page 1128)

r 41111',4 1

High spots O OÓ PIP-4d -Gage Ball Nº.I 0.00006 Large 0.00017 large Scale on templet 0.00008 Large I Arrows from points of ®0.00012 Large contact show direction , ¡ of wedge.

\ ii Ball Nº.2 6 4'- bands' Exact si e 0.250';' 000009' large Bonds`\ 2 , fl.00002 rt 1 i Large' Arrow starts 'from point of con 10 ; 0.00004 Large' Point of Point of Cordboard templet O , tact and shows direction of 1 contact contact' 0.00006' ¡ 0.000045' Point of contact we e. Cardboard tempi / let. i r In 00011, Upper flat S

1-The interference bands shown above, locate vertical steps of .00001 inch between the contacting surfaces. They are shown here in an exaggerated condition, the optical flat resting on a gauge. 2-Curved bands indicate curved surfaces. The side edges are low by five millionths of an inch. 3- Convex surface; side edges low by ten millionths of an inch. 4-Side edges rounded; five millionths of an inch. 5-Surface hollow in center, higher on each side of center. Error of three millionths of an inch. 6-Note the high spots in this example; error, sixty millionths of an inch depression. 7-Comparing two gauges; top and side view shown. The standard gauge is three and a half bands, or thirty-five millionths of an inch shorter than the unknown gauge. 8-Measuring the size of a ball by means of a cardboard templet, and lower and upper flats. The ball is oversized by five and a half bands, or .00011 inch. Five and a half bands must be doubled, because of location of the point of contact. 9-Balls are not uniform in size. 10-Measuring the size of a plug, the plug is .00012 inch larger than the gauge. 11-Plug shown above is .000045 inch smaller than the gauge. 12- The tapering plug shows bands as indicated in the illustration, the bands inclining relative to the plug. 1067 Machine MaRes 112,0009000 Key ess Codes By H. Do HUHTER.

OCCUPYING less than a cubic foot of eluding the United States, has been sub- of the invention. On the space upper half of the and weighing less than a port- jected to fifteen months' experiments by front of the box are 26 small transparent able typewriter, an electrically driven agents of the American Secret Service, in dials, arranged in three rows, on each one machine which codes, transmits and decodes an effort to decipher messages sent by it. of which is painted a letter of the alphabet. So far, according to the in- This is the receiving deck. Directly under ventor, they have failed to this, occupying the lower half of the front decode one word out of hun- is a series of 26 keys, also containing the dreds on which they have letters of the alphabet, arranged in the same worked. The machine, whose order as on the "universal" typewriter key- basic principle is that of the board. telegraph -typewriter, can be used for all secret messages, send- With the machine as far as described, ing and receiving either by wire messages may be sent and received in plain or radio. English or in any other language using the English alphabet, or one approximating it in characters. The brain of the invention, 1,,.111111111111111111111,1111111111111111111111111111111111111111111,,,,,,,101,,,,,,,,,,,,,,11 however, is a little spool, about three inches in diameter, or less, and rather more than This tiny machine, weighing less half an inch in thickness. Around the than a portable typewriter, is cap- sides able of transmitting codes and also of the wheel, spaced around its edge decoding messages. None of the at equal intervals, are 26 openings, through codes are keyed, so that it is quite which are impossible to decipher the same by seen the letters of the alphabet. ordinary mathematical means. There On the rim, likewise, are corresponding are about eleven million separate apertures, and distinct code combinations showing the letters in the same possible with it. order.

lllll 111111111111111,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,,1,,,,,,,,,,,,,,,,1,,,,,,,,,,,,,,,,,,,,,,w The inventor will say nothing about this spool, which he calls the key wheel, and without which no codes, other than the ordi- The instrument-which is still nary codes, made by man, and, therefore, waiting de- for a name-presents cipherable, can be sent. Inside the wheel, the appearance of one of the each letter -space is early wax cylinder phonographs. connected by a separate Its case wire with a binding post in the center. There is 8 x 10 x 6 inches in are dimensions, and it weighs six possible, with these 26 letters and 26 nearly 12,000,000 different, unrelated and pounds. From the top of this box rises a wires, entirely different combinations num- keyless codes has been invented and patented half cylinder of metal, divided in the cen- bering 11,881,376. By means of inter -codes, by Edward H. Hebern, of California. ter by a slot rather more than half an inside -codes, codes -within -codes, etc., it is Hebern's invention, which is now under inch in width, into which drops the key possible to make codes to the number of test by the code experts of five nations, in - or master wheel, which contains the secret 403,303,146,321,064,400,000.

Eeheir Used in ManufaceuTIlng lice Clc eam.

Ether, that light, volatile, inflammable United States where the application of ice to an insensible quantity. The use of ether liquid so widely used as an anxsthetic be- mixtures is difficult because of the excessive in determining the expansion of ice creams, cause of its power to produce insensibility temperature in a desert. The use of ether gives a cleaner and more easily regulated to pain, has been adapted to a new role of in the manufacture of ice-cream, however, method than the present system of determina- usefulness. P. N. Peter, a chemist in the is a fresh application of this liquid com- tion by weight. It is, however, the costlier Dairy Division of the United States Depart- monly identified with operating rooms and of the two. ment of Agriculture, recently discovered its hospitals where human pain is to be reduced Contributed by S. R. WINTERS value as an agent in determining the expan- sion when freezing ice-cream. It is the first time ether has been applied in the process of refrigeration of ice-cream. The determination of the expansion in freezing ice-cream is essential to the success- ful manufacture of this popular delicacy. The manufacturer terms this expansion an "overrun," which indicates an increase of the mixture over the original quantity of ingredients. The prevailing method of mak- ing known the percentage of expansion is to make comparisons in volume of a sample of the original mixture and a specimen of the "overrun." In the manufacture of ice- cream, air is whipped into the raw product, the injection of this air being primarily re- sponsible for the inflated yield. The apparatus for making the expansion determinations consists of a large Dewar flask, wrapped with a heavy layer of felt. Two concentric glass tubes extend through a cork into the center of this flask, the space between these two tubes being occupied by air which serves as a means of uniformly lowering the temperature. A dilatometer bulb and a thermocouple are contained in the inner tube. Temperatures are measured by means of a five -junction thermocouple, while dilation is determined in a capillary tube. The use of ether in refrigeration methods has been occasionally employed in plant ex- Above we see the modern periments in extremely method of determining the expansion in arid regions of the ether instead of the weight freezing ice cream by using system for indicating the degree of expansion. 1068 PAINTED TO REPRESENT 'CANDLE

PILL BOX SINGLE STROKE RUBBER 'PILL DIAFRAM BOX BELL RUBBER WIRE BRUSHES DIAFRAM IN TABLE TOP AND BASE OF CANDLE STICK l FIBER CLOTH aeüiao%-ioídlll h1 g -4-TABLE GAS FILTERS THRU CLOTH ON TABLE

command of the operator, are developed by a tambour device The effects produced by the flames of the candles in which their light flares up at the candles. Illuminating gas supplies each candle, the single stroke bells striking against the rubber diaphragm placed in the gas line of the individual by an assistant behind the up. The detail in the upper right hand corner shows the apparatus required, which is controlled cause the flame to spurt scenes. .- tA MPH KRAUS THE OBEDIENT CANDLES

famous the figures you have given, I wish I was promptly informed which candle had HENRI HARGRAVE, the totalling by to give me you would look at the candles. A flicker replied by the number of flicks delivered magician, had promised the next question was information regarding the Obedi- denotes a numeral. Three flickers in suc- candle No. 6, to which a new electrical nov- cession signify 'yes,' and two signify `no' put. ent Candles, My age was given by candle No. 10, and elty, which he had just invented, so, when numerals are not being considered. In this way, the candles will not only answer many other replies which were received were inasmuch as I already had an appointment humorous. I did not hesitate to keep, I your questions, but will also add, subtract, extremely with him, which write down Hargrave did not manipulate any controls. soon found myself in the throes of mysticism. multiply or divide for you. Just were the number of flicks which emanate from Finally he reached over, grasped one of the On a table in Hargrave's laboratory and blowing the flame out, came respective candlesticks. the individual candles for your result." candlesticks, ten candles in their The first toward me. I examined it and found it to "It won't do you much good to examine Immediately my answer came. candle at the extreme left did not waver, the be an imitation candle, having a metal top them," Hargrave commenced in explaining hole therein. Aside from that, have heretofore next one flared up and down five times in with a small the trick, "because, as you did not seem at all suspicious. It was up of the apparatus which I succession, the third one four times, the it found, nearly all According to to Hargrave to give me the details. The be examined by skeptical individ- fourth one seven, and so on. build, may was correct. It took base seemed so thin, it would have been So I will show you what the effect is Hargrave, my answer house uals. me some time to figure up the amount, but almost impossible, in my opinion, to at first and follow this up with the explana- therein The usual paper when finally I succeeded I found that the any electrical apparatus tion. Suppose you take a sheet of of making contact by means of a series of num- candles had told the truth. I asked them to method and a pencil, and jot down and points, was not in evidence, although I did with the figure 1, if you subtract one number from the other, bers, commencing line beneath the second notice two small wire brushes projecting like, and culminating at the figure 9,999,999. before I could draw a group of figures I had jotted upon the paper, from the base of the candlestick -holder. You may choose as many figures as you up one of the candle- then total the candles were responding. I then com- Hargrave opened desire, in any arrangement, and sticks, and the entire system was revealed. them out as you write them." menced to ask them several questions. The them up. Call in unison. I then Essentially it was a gas appliance. A thin I was calling out the figures, he was entire group replied While changed my tactics and asked the reply of copper tube led to the top of a fake candle busy lighting the candles. Needless to say, resemble the real object, but for them down as I candle No. 1, which was forthcoming. The painted to I called out a group, jotting for which a real one could be substituted if would stagger a skilful public flame in the others did not move, except did so, which of air, caused by, an open desired, the essential fact being that a hole if he attempted to total the a slight draught to accountant, window some distance away. When I asked must be drilled through the candle itself, amount. 1 permit the introduction of the copper tube. turned to me just as I had ex- of candle No. 3 whether candle No. replied Hargrave two flicks indicated 'no,' and (Continued .on page 1113), claimed "That's enough!" and said, "Before to my question, 1069 FIRS I' PRIZE, $25.00 .111,1Illen,,ullIuIn,ttm,,,,,,elmemmr/In,,,,,,trmIcerl,.,,,l,,,,, that the bare wire will not project through BATTERY CHARGING ELECTRICITY ON REGULATOR THE CAR the end of the tube. Put in a vise and squeeze the tube, being careful The illustration shows the construction We believe that there are hundreds of not to break new electrical ideas that can be incorpo- any part covering the insulation. A hammer and connections for a charging regulator rated in the car that our readers would can be used to close up the tube if a vise like to know of. What we are particularly is not available. tights - Sockets interested in are novel stunts, new devices, The wire and the inside of new kinks, and new hints made possible by the tube should be clean, and the tube press- the electric Wood current. ed, so that the tube and wires are like one In order - base to win a prize the first requisite is that the device or suggestion be practical. The term PRACTICAL will be the key- To switch To ground note of this contest. You will be more apt to win a prize if Copper tubing Fig.4 you will design the device yourself, and make a photograph of it, sending the same to us. Ideas 'Overcharge are all right, but the reader -charge" cutout sw. ham. wants to see that the device actually has been made, and WORKS. O The following prizes will be paid: Regulator Tubing .y pressed, SW. sw. "Leva FIRST PRIZE $25.00 gnition and v SECOND PRIZE 15.00 headlight - sw. THIRD PRIZE 10.00 Relay vì .. R All other accepted articles which no A clever method of © © win making a lug for a wire [iiio prizes will be paid for at the rate of $1.00. terminal is depicted above. The rubber w're Min! Each article submitted should not be longer is bared, twisted into loop, than about a and pushed into Gen. Regulator Battery one hundred to two hundred a piece of copper tubing which is then flat- words. tened in a vise. Address all manuscripts to EDITOR "MOTOR HINTS," care of this publica- piece. A part of the tube covering the insu- Fig.2 tion. lation can be broken if thought necessary, The circuit diagram above shows how to con- so that the insulation is clinched in the ter- nect a number of lamps across the battery, minal. so that the dynamo will operated from the storage not overcharge said battery, the same Contributed by ALVIN storage battery, when the car is being used as if the engine were not running at all. HEDWALL. on long distance runs. The voltage of a storage battery on open circuit A MAGNETIC HAND FOR switch mounted on the dash hoard of the does not mean anything, and the po- AUTOISTS car. On long drives, or at any time when tential could be read either while the dyna- mo is charging The little device described herewith will there is danger of overcharging the battery, the battery, or else while prove itself the regulator the battery is discharging, lighting to be of no little value in picking switch is turned on, and the the head- iron objects from the multitude charging rate will be diminished, lights, etc. The potential when fully charged of inacces- the amount sible places into which they seem to have the depending on the number of lamps used and will be about seven volts. If a dynamo is their charging the battery, the habit of falling. candle -power. Extra sockets are pro- voltmeter will in- It consists vided, which are not in the circuit, dicate about nine volts or more; discharging of a small electro -magnet and may with wound for six volts, attached a be used for carrying extra car lamps. the dynamo disconnected , the battery to brass rod As shown potential will register about seven several feet in length and % inch in diam- in the diagram, it is the best volts or eter. Current practice to connect a voltmeter less, when fully charged. from the storage battery passes across the through the rod to one terminal of charging wire from dynamo to ground, to- Contributed by FLOYD OAKLAND. the wind- gether ing and returns from the other through a with a suitable push button switch, so well insulated that the condition of the McLaughin or Buick car, and which has wire which is affixed to the battery can be as- rod by means of thread or tape. certained before by passing some of worked quite satisfactorily. Any gasoline The rod, the gauge be being of small diameter, readily admits be- charging current through the headlights as can insulated at the proper inter- some vals by cardboard or fiber for the ing bent into any desirable shape to reach drivers do, or else through the regula- live side into different tor lamp bank, as here of wiring, and the inner strip is grounded places, enabling the workman suggested. Some directly to easily remove bolts or nuts garage mechanics recommend the placing of to the dial or gauge. Where gauge which defy a switch is used for filler cap also, snap every effort to take them out with the fin- in the main charging wire from connections gers. the dynamo as here shown can be employed, or a collar of composition also, so that if with One hundred feet of No. there is danger of heat developing within contacts imbedded, could be used to 28 enameled the battery, slip over and around the gauge. Roughly copper magnet wire wound for W4 inches on this switch can be opened, an iron core thus allowing the when the tank is three-quarters to one half 5/16 inch in diameter will dynamo to run idle, the full, the readily lift iron objects weighing battery of course receiving no charging cur- clear light circuit is complete; when up to one- rent. one half to one quarter, the green half pound. It draws .9 ampere, and heats In this case the ignition and lights are light; up only on quarter to one gallon the blue, and at slightly with continued operation. SECOND PRIZE, $15.00 the one gallon mark the red light and buzzer Contributed by H. A. HrciisToSE circuit is completed. Of course, LAMP SIGNAL this would Switch, Insulated z ft. brass rod GASOLINE GAUGE not show the exact number gallons of in the ,e wire) i' diam. The accompanying drawing shows an elec- tank with only four lights, but the system tric gas gauge which I have installed on a could be carried on as far as one should care to go. This notifies rlollow, Clear Green Blue Red Buzzer the owner of the Buzzer car that when the handle too ft. ea magnet wire SW. buzzer rings, he had better 0_1:°, fill up his tank at the next gas station. telegraph sounder iron core rs3 Contributed by J. B. HALL. THIRD PRIZE, $10.00 IMPROVED WIRE TERMINALS A solderless insulated wire terminal, which will keep the wire from breaking where it joins the H111111111111401 terminal, is here shown. It is made , of a piece of copper Storage bat r. or brass tubing. A piece of tubing just large enough to slip over the insulated wire is Contact strip---.--- procured, and this - should fit tightly. If the tubing is too large, Grounded strip-, `, the wire can be tapped to the proper size, or if too small, the insulation can be cut down. Then strip wire of insulation for about one and Brass roller -- a half inches or more, ac- The safety gasoline gauge indicates how much cording to the size of the wire, and bend gasoline is in the tank. When the supply stripped wire in the A magnet mounted on is center. Slip copper or the end of a rod enables running low a red light is flashed, and a brass tubing over the automobile owner to pick up screws buzzer stripped wires, and about have fallen Which operated simultaneously. one -quarter of an inch of insulated into almost inaccessible places. part, so This does not apply to brass screws, however. 1070 5cIloentinc IPTobItern5 an uzze ERNIEZT rg.o CHAPHN NO. 6 OF A SERIES IN- shown in Fig. 2, one of which admits com- OR SOFT? BOILING WATER WITHOUT reaches the bot- HARD-BOILED CREASE OF HEAT pressed air when the balloon customer tom and the other which releases the pres- AITER," called the new sir," said one barber wisely to an- at the top. man who had just served "Yes sure as soon as the balloon arrives to the other, "it's prefectly marvelous the advances his scheme can be made to him, "take these eggs away and thing Do you think science is making these days. First if so, what would cause the bal- bring me some soft-boiled ones as how to keep work, and we'll know somebody'll show us loon to rise and fall? I ordered." coal, cook our food without eggs yet, sir," warm without "But you haven't opened the gas and-" THE HYDROSTATIC PUZZLE the waiter, with difficulty conceal- interrupted objected "Shucks, that ain't so much," Let us suppose that we have a device as il- ing his irritation. a small boy who had been listening, "I'll tell you what I can do right here and now. Gim- me a flask and a tight rubber stopper and PIVOT w111w111111.1111111111111 N K 11 1 1 i in w1 w 11111wmwi 1 11 1 1 1 1 1 1 tetttumtt..11111111111mn1111 4. 1 1 11 11 1tg1 n.l ,mmmm EXIT Although it is an invention well over two Iil;,l; thousand years old, Hero's fountain still pro- VALVE vokes considerable interest wherever one is shown. The problem is to find out how the FOR AIR water keeps squirting upward through the central jet at the top, without the use of pumps, heat, etc., Fig. 1. The authors Fig. 2, at extreme right, shows plan conceived by a store -keeper for a show - window display. He desired the small balloon to rise and fall alternately, this action to be kept up simply by means of a tank of com- pressed air. Do you think this scheme will work? B

I'll show you how to make water boil again after it has stopped boiling and I won't add anything to it and I won't TO apply heat." Can you explain how he did it? COMPRESSED HERO'S FOUNTAIN AIR TANK is well Although it is an invention that 1 old, Hero's foun- over two thousand years PIVOT was puzzled indeed when his cus- considerable interest The waiter long the tain still provokes told him at a glance just how 1 illustrates tomer by looking wherever one is shown. Fig. SPRING eggs had been boiled. Can you tell mechanism. When at an egg whether it is soft or hard boiled? the construction of the the upper reservoir (E) has been filled lustrated below, consisting of a piston (P) have to open 'em," snapped the with water and a little water is poured into (C) which connects at its base "Don't delivers a in cylinder customer, "but if you don't believe they're the upper basin (A), the device with a small vertical pipe (p) open at the show you." And so saying he stream of water well above the source in The cylinder and tube are first filled hard I'll about the top. cracked the eggs open and proved his point. apparent defiance of our notions with water and then the man stands on the "I'll bet I can tell how he knew the eggs impossibility of perpetual motion. platform on top. Assuming that the area of were hard," the waiter said to himself as What is the explanation of its action? the piston is 2 sq. ft. and that of the pipe he went off after more eggs. "He simply PROOF OF THE EARTH'S 0.1 sq. in., how high will the weight of the shook them close to his ear and noticed that ROTATION man and piston force the water in the move inside." In a few and piston together the contents didn't Supposing that our skies were always pipe (p) if the man cloudy so that the rising and setting of the weigh 200 lbs? sun and stars could not be observed, are there any facts that could still be observed or any experiments that could be performed which would demonstrate the earth's rota- tion? PRACTICAL LEVITATION Wishing to attract people to his window displays, an ingenious storekeeper proposes to construct a tall glass cylinder in which a small balloon of light but rigid material al- ternately rises and falls with its load of miniature passengers. The only motive power which he claims he requires is a tank of com- pressed air and the only mechanism neces- sary are two valves operated by levers as

If the man and the piston, P, shown in figure above, weighed two hundred pounds, how high do you think they would force the water in the A boy showed two barbers a new trick in boil- open tube "p." ing water. With a glass flask and a tight to make rubber stopper, he showed them how on the water boil after it had stopped boiling, Without a doubt the two problems without adding heat. Simple-when you know practical levitation and the hydrostatic how. puzzle, will attract considerable attention. versed in physics problems will minutes he was back with another pair of Those well find even then that the results obtained in eggs. will startle customer particularly the last problem, "That's better," approved the first problem given on this page, had even touched them, them. The this time before he if practised, is found to be easily duplicated, "thank you." And away went the astonished to man and the individual who takes the time waiter wondering whether to think the rules or rather guesser or whether he memorize the few simple was merely a good which boiled eggs produce when re- really had some uncanny knowledge about Diagram to accompany the problem on how effects to prove the earth's rotation on its exis, pro- moved from water, will be amply repaid for eggs. viding our skies were always cloudy, so that the time spent in memorizing these facts. how the of the sun and stars Would you venture to explain the rising and the setting (Continued on page 1108) man knew? could not be observed. 1071 1-Many thousands of dollars' worth of radium are contained in these large vats. The solution is carefully sampled a number of times each 2-Part of the process of extracting radium. 3-No cook ever watched a pot boil ¡more hour. radium in carefully than these chemists with over $500,000 worth of their care. 4-This picture shows what remains from the big bowls on the long stove.

reueeical emica: Ex.peri ; nts By RAYMOND B. WAJLES FIRST PAPER OF A NEW SERIES THE extraction of radium from the filtrations with the mineral carnotite is as interesting as Emtracti®n of ReC hUIlm resulting by-products make the experiment both practical in value the application of this wonder ele- g'Irovn and interesting ment to human life. Carnotite in schematic chemistry. METHOD OF Carnotite is a radio -active mineral EXTRACTION now being mined active rays passing through the aluminum The pulverized mineral is first heated in Colorado, for its varied side with contents, mainly for radium. Its appearance or back of the camera. strong nitric acid (step A) and filtered, the closely resembles a piece of dried -out yel- The Bureau of Mines, co-operating with residue being treated with more strong acid low clay, but with properties totally different the National Radium Institute has perfected again and filtered, the two solutions or fil- from the latter. The mineral is radioactive, a method by which the carnotite ore can trates being united. The residue is sand or emits radioactive rays, because of its ra- be worked up and radium salts isolated in etc., and should be discarded as in actual dium and uranium content. a very simple manner. practice. The solution contains radium. The rays which The constantly pass off from the mineral are to- author has worked out the Bureau uranium, iron, vanadium (with which vana- tally invisible, even in of Mines process with half a pound of car- dium steel is made), calcium, the dark, for the sub- notite, aluminum, stance is not phosphorescent as many be- and has had no difficulty in obtain- etc., as salts. Sodium hydroxide solution lieve. The purer compounds ing radium in the form of radium -barium is now added (step B) until the solution of radium do, sulphate. is however, emit their characteristic bluish About one gram of this substance almost alkaline, but still slightly acid. If glow visible in subdued light. was obtained. The presence of radium in alkaline, a precipitate will form which is not the substance was verified by utilizing its desired. Barium A simple test for radioactivity in chloride solution is now a sub- radio -photographic effects. A paper clip added, and then sulphuric acid. (step stance such as carnotite is fogging by the was placed C). mineral over a sealed photo plate and (Use about 20 cc. of 10% solutions of of a photographic plate or film the radium -barium sulphate (in its each). The wrapped up in paper, con- white precipitate which forms which has been ex- tainer) was placed over the clip. Develop- is radium -barium sulphate. Filter. posed to the substance for several days. The ing the plate after twenty hours produced The precipitate is dried, after washing, radioactive rays of the uranium and radium the effect shown in figure 1. Carnotite min- and preserved. It contains practically all contained in the mineral will penetrate the eral applied in the same manner did not paper covering af- of the radium which was present in the in which the plate has been fect the plate during the same length of quantity of wrapped just as light time, conclusively ore taken. This double salt can will pass through the showing that the radium be used in many radioactive experiments lens of a camera. A piece of carnotite rest- barium sulphate contained practically in all of which a rather strong unit of radium is re- ing on the film side of a loaded kodak will the radium contained in the half pound of quired. cause a fogging to appear on the film when material processed. In industrial The practice, the radium -barium developed. The carnotite should be at rest chemical experimenter should not sulphate precipitate is heated have the least bit of with carbon, on the camera for several days. "Radium- difficulty in working in furnaces. This reduces the sulphate to up a quantity (from a quarter pound or the sulphide ized" light buttons, pull -chain pendants, etc., more) by taking away its oxygen. of the carnotite mineral for its rad- The resulting radium and can also be used in this manner, their radio- ium content. The simple barium sulphides precipitations and are dissolved in hydrochloric acid and the 1072 hydroxide is added (E). The uranium will a high temperature yields uranium oxide, solution obtained is fractionally crystallized and glass mak- radium chloride from precipitate as sodium uranate. This is finding use in photography, so as to separate the iron vanadate is worked over and the worthless barium chloride. It is not used in making yellow glass for vases, auto- ing. The mobile headlights, etc. Filter. The filtrate the vanadium used to make vanadium steel. practicable for the experimenter to reduce solu- (carbon) and is completely neutralized with nitric acid At step D, the sodium carbonate the precipitate with charcoal i. e., until no more acid and frac- and a solution of ferrous sulphate added. tion is added in excess, then dissolve in hydrochloric The solution is then tionally crystallize. (F). Iron vanadate (black) is precipitated. precipitate forms. now nothing boiled for half ali hour, filtered and nearly radium - Filter. The solution contains The filtrate obtained from the impurities. If the neutralized with nitric acid and sodium hy- precipitate should now be but sodium nitrate with barium sulphate solution is concentrated and allowed to cool droxide solution added (step E), until the treated with a boiling sodium carbonate of of sodium uranate no This precipitates iron, in a quiet and covered place, crystals yellow precipitate solution (step D). sodium nitrate will form. In actual radium longer forms. The solution should he hot calcium and aluminum which were contained with filtering, the ferrous mineral. In practice, this is manufacture, these crystals are treated at this point. After in the original acid to make nitric acid solution is added to the cold solu- being worthless. The filtrate strong sulphuric sulphate discarded, it which is then used as the neutralizing agent. tion, or filtrate (step F). or, to dissolve the original mineral as in the The above precedure used by the National very first step. Radium Institute and the Bureau of Mines One of the photos shows evaporating pans can readily be duplicated by the chemical used to crystallize the sodium nitrate from experimenter on a small quantity of carno- the final solution. The mass of solid salts on the draining trays is, sodium nitrate ready -Radiumized pull -chain pendant for nitric acid manufacture. Lead foil ! ,Cut out initial UTILIZATION OF BY PRODUCTS All of the by products find a ready mar- ket. The sodium uranate when heated to

MINERAL, NITRIC ACID

C FILTER Camera Red Wirìdow BARIUM CHLORIDE RESIDUE SODIUM SULPHURIC ACID eas- DISCARDED HYDROXIDE Fig. 2.-You can make a radium picture very ADDED ily by using your camera and a radium "button." from a piece of PPT Cut out a small figure or initial FILTERED heavy lead foil and place this on the back of the WASH FILTRATE camera; then lay the radium luminous button RADIUM. foil. Do not dis- Fig. 1.-To make this radium photograph, the BARIUM SODIUM CARBONATE D over the cut-out portion of the SULPHATE film to the next author places an ordinary wire paper clip over ADDED turb for several days. Turn the PPT cartridge in the a sealed photo plate, while the radium -barium FILTERED number and use the rest of the in its was placed over the FILTRATE regular way. sulphate container CARBON REDUCED BROWN IRON - clip. Developing the plate after twenty hours, CALCIUM ETC PARTLY NEUTRALIZED produced the effect shown. l SODIUM HYDROXIDE E HYDROCHLORIC ACID tite mineral. The by-products obtained, PPT ADDED and attractively labeled make from the solution now contains sodium FILTERED when bottled FILTRATE a interesting exhibit. vanadate uranium sodium RADIUM -BARIUM CHLORIDE very and the double (FRACTIONAL CRYSTALLIZED) NEUTRALIZED, FERROUS SODIUM URANATE must be understood that the percentage carbonate. The yellow color of the solu- SULPHATE - ADDED F It PPT tion at this point is duc to the uranium pres- FILTER of radium in carnotite is infinitesimally IRON VANADATE FILTRATE low, and what may be called "radium chlor- ent. RADIUM -1(' BARIUM EVAPORATE. only a minute proportion of Nitric acid is now added to the filtrate CHLORIDE CHLORIDE ide" contains until nearly neutralized and then sodium SODIUM NITRATE CRYSTALS the salt. Urch5u5peced FunceIl©n of 5u{gair By Ca Lo MELLER IT is twenty-eight below zero; on either yield sugar, including even that veritable bud growth. It is this sap, this almost side of the sun may be seen the weed of a tree the box elder. Nor is pure sugar solution, that freezes solid phenomenon popularly known as sun - the production of sugar limited to this during winter's zero weather. clogs, while among the timber is heard genus. for we find that the sap of such That freezing does not harm this sap the trees as the walnuts and the birches is obvious from the very fact that the an occasional sharp report as of The discharge of a pistol; it is a little un- can be boiled down to a sweet syrup tree can grow again in spring. at night. However, the noise comes and finally to sugar. Even trees like the question why the sap is unharmed finds canny The sap a only from a tree here and there de- ash that do not give their sap by bleed- an answer near at hand. of veloping a frost crack. A little water ing in spring contain an appreciable sugar -producing tree can be boiled down lodged in some small wound is sufficient amount of sugar, which will boil forth to any desired consistency and then 'be to start the trouble and under the in- freely from the cut end of a green stick brought back to its former state by fluence of the intense cold a crack de- of this wood as it burns. Many an simply adding water. Even the final velops longitudinally in the trunk just Indian child knows of this source of a sugar can be redisolved to its former as water pipes burst when the water in bit of sweetness. degree of dilution without any change them is frozen. Yet trees live through In the individual cells, those innumer- from the original sap, provided of course winter after winter of just this kind able little laboratories of each green leaf, that the impurities are not in the water of weather, altogether unable to de- the elaboration of starch goes on apace. added, a contingency that can be fend themselves against the cold, their Now starch being a carbohydrate, a avoided by the use of distilled water. sap frozen to the very center of the chemical group to which sugar also be- Records show that the yield of sugar trunk. longs, it lies within the power of the from the sap of a tree varies from year Of her means of accomplishing this plant to change starch into sugar. Per - to year, as indeed does the yield of the apparently difficult feat, keeping trees Imps it is more accurate to say that sap itself; the sugar content of the sap alive through prolonged periods of sub- plant. starch is changed to sugar, sugar may be as low as a fraction of one per- zero weather, nature makes no secret. being soluble while starch is not. The cent or as high as five percent due al- She employes sugar to gain her end manner of this change, having no bear- together to the influence of the season, and has been telling us so, ever since ing upon the special function of sugar which as yet is by no means fully under- we began to use maple syrup for break- at present under discussion, is a detail stood. But an analysis of the sugar re- fast cakes. With the processes of plant which we can spare ourselves discussing veals it to be almost pure cane sugar life such as they are. it becomes per- here. Sugar then is the form in which with the addition of about one half of fectly obvious to the chemist that sugar this elaborated plant food, this carbo'iy- one percent of ash. However, the per- is the only substance that nature could drate. is transferred from one part of centage, of sugar is of little importance have employed without adding another the plant to the other through the me- as compared with the fact that the sugar detail to plant metabolism. A scientific dium of solution. When the leaves fall is present in an almost pure solution. determination, a sort of diagnosis so to in autumn the manufacture of starch It now remains for us to see how speak, brings forth the following facts. ceases, while that which has been manu- this acts in relation to extremely low To begin with, we find sugar produc- factured is in solution but transformed into temperatures. After being thawed out ing trees growing not only where there sugar, though of course by no means all, a sugar solution is its old self again is a well defined winter season, but the greater part of the summer's out- and can act its part in every way that where that season includes periods of put having been used up in the process it did before it was frozen. It is this low temperatures. Not alone the hard of growth. Enough however remains to fact that solves the problem of a tree's or sugar maple but all the maples will start growth again in spring, especially (Continued on page 1099) 1073 p riment 1 cero -Chemistry RAYMOHD Ba WAll LEG

PART 9-ISOLATION OF METALS, DYES; PREPARATION OF METALLOCHROMES, LIGHT BY MEANS OF ELECTROLYSIS

THE electrolysis of aqueous (water) from flashlight cells. They pass through a This mixture, when rubbed solutions by the with a mois- electric current plays stopper. Two burettes are placed over the tened cloth over the object to be plated, will an important part in modern indus- electrodes as shown. The vessel is filled deposit a coating nickel. try. Copper of The talc and for instance, which goes with water acidulated with sulphuric acid, chalk act as retarders for the chemical action to make copper wire for electric lines the stop -cocks at the top being opened and and as polishing agents. is recovered or separated the The metal zinc is from impurities water sucked by means of a rubber tube, higher in the electromotive series or more to the top of the stop -cocks, after which they are closed. The electrodes can be connected Carbon to a battery (storage) and a rheostat or Steel 110 volts D.C. using a lamp bank resis- tance Acidulated in series. On passing the current wate; hydrogen will form in the burette over the negative pole and oxygen over the positive, or anode. If the acid is replaced by a solution of 1 part potassium sulphocyanide in 5 parts of water and the current passed as before, hy- drogen will be liberated as before, but there will be no formation of oxygen at the anode

for the following reaction will take place : 6HCNS -l- H2O=C0H,02N4S5 - HZSO, -1- 2HNO, FIGI The reaction product, COH,O,N4S,, is kan- arin, a yellow organic dye. The dye forms Rheostat about the anode and after interrupting the Opti ono I current, can be scraped off the carbon anode, To 110 dissolved in alcohol, and cloth can be dyed V. O.C. 110 V. D.C. with Fig. 2.-Using this simple set-up, metallic mag- the solution formed. It is best to use nesium can prepared --- r 100 be from magnesium chloride. S)7'7;77.122 -j volts D.C. with several 16 C.P. lamps An ordinary clay bubble pipe is used as the in parallel for this experiment. reaction vessel. Lámp bank ' PREPARATION OF MAGNESIUM Bat ry% positive than nickel, and displaces it from An ordinary clay bubble or tobacco pipe the solution, which is soaked up by the Fig. 1.-Hoffman's apparatus is easily made. The can be used for this metallic separation. A cloth and the nickel ammonium phosphate, yellow dye, kanarin, can be made with the aid steel knitting of it needle should be passed through deposits nickel by electrolysis or electric the stem so that its end will project into the plating, on the metal which is rubbed with by means of electrolysis. A general state- bowl of the pipe. This will form the nega- the saturated cloth. ment tive pole or cathode. can be made that all metals will pass The pipe should be METALLOCHROMES toward the cathode or negative pole when held in a suitable clamp and a Bunsen burner electrolyzed, for the metals in solution have placed beneath the bowl. The bowl is filled Using the experimental cell shown in fig- positive charges of electricity upon a por- with a mixture of magnesium chloride, am- ure 3, beautiful effects called metallochromes tion of their atoms which are called cations, monium chloride and potassium chloride, can be formed. The electrode (cathode) is they being ions. So it is with copper, which prepared by dissolving 20 grams of magne- a pointed wire, directed toward the anode, collects on the negative electrodes in the sium chloride, 7.5 grams potassium chloride a sheet of copper. The following solution 'electrolysis of copper solutions made by dis- and 3 grams of ammonium chloride in water is used: 125 cc. water, 3 grans lead nitrate; solving metallic copper in an acid. and evaporating the solution to complete 25 grams of sodium hydroxide in 125 cc. A pretty dryness in an evaporating dish. The result- water. Mix the two solutions when ready experiment showing how a dye ing can be produced by electrolysis, salts are then introduced into the pipe for use. This forms sodium plumbate, a or electro- bowl and salt lytic oxidation, can be performed with the the Bunsen burner is lighted so as of plumbic acid. aid of a home-made to melt the mass. A carbon rod from a flash- Colored rings will be produced on the Hoffman's apparatus for light the electrolysis of water as shown battery will serve as an anode and is copper plate when the current is passing. in figure introduced into the 1: melt in the bowl. A cur- .Nobili's Rings rent f rpm a 110 volt D.C. current stepped A bottle is cut off near its bottom by filing down with lamps Nobili's a mark should be passed for about rings are a form of metallo- around its circumference to a dis- half an hour. When the chrome and can be produced tance of about an inch, current is then in- by laying a and a red hot rod terrupted and the mass cooled, globules sheet of brightly polished iron on the bot- bent in the shape of the bottle is touched of to metallic magnesium will be found to have tom of a vessel containing a solution of lead the file mark. Immersion in cold water will formed start the about the steel needle, or cathode. (Continued on page 1116) crack around the bottle. The two They can be mixed electrodes used are with a small amount of carbon rods obtained potassium chlorate and ignited, producing the familiar flashlight Buttery effect. NON -ELECTROLYTIC DEPOSITION OF METALS Metals can be plated from a solution using two sheets of metals immersed in a solution of a metal and electrolyzing or passing a current, using the metal to be deposited as a solution and the object to be plated with the metal as the cathode or negative elec- trode. This it will be recalled, is the princi- ple of the copper voltameter. Metals will displace other metals from so- lutions without the use of the electric cur- rent. A sheet of iron placed in copper sul- phate solution will become covered with metallic copper. The coating is not lasting however, its spongy state allowing it to be rubbed off quite readily. Galvanite is the name applied to a paste consisting of : Nickel ammonium phosphate 60 parts FIG.3 Zinc dust Film of Hydroxide Fig. 3.-Metallochromes 3 parts are easily produced and Chalk 30 Fig. 4.-This electrolytic cell will produce a light are of great beauty. parts when a direct current Talc (powdered) 7 of 110 volts potential is parts passed through it, using a lamp bank resistance. 1074 THE CONSTRUCTOR. th .

Lo No WralIG .FUC1Tn Il3efrIlgeratñn Engineer To facilitate welding and careful l' following the present article repeat the same cycle, which it does an closing. number of times with little or no inspection the pressure head may be un- closely any one, with a little me- indefinite has been marked his loss. bolted, after its position chanical inclination, can build proper replacement. Before reset- 13 own plant at a nominal sum and The item that will give the builder the to insure is the compressor. ting, clean the surfaces thoroughly and apply enjoy freedom from the messy use most work and concern from be with a bore of from one a gasket of thick drawing paper, free of ice. Such a plant as described can An air compressor into shellac. Apply dollars or less. to two inches will answer the purpose. Upon ci acks or cuts, dipped assembled for one hundred to the head bolts evenly when re- Before attempting to build his plant the close examination it will he observed that pressure several avenues by which the setting. layman should understand the principles there are side shaft, opposite the refrigeration depends. Under gas is likely to escape. A little patience, The blind of the upon which is remedied by cutting off any pressure the refrigerant is in a liquid state skill and ingenuity will remedy them in flywheel side, ref ri- order. The following remedies for projection of the shaft, so that after planing and flows as such to the point where short a piece of At place it passes faults in compressors may seem too numer- smooth the face of the hearing, geration is desired. that iron can be bolted across the opening through an expansion valve, which as its ous, but they are simply stated to cover the sheet makes of compressors. by means of studs. Before fastening per- name implies, allows the liquid to exi and various has clearance which absorbs heat. This ;as, The unloading device upon the pressure manently see that the shaft into a gas well shellacked gasket of paper, laden with heat absorbed from the ice- ,ox, head will claim first attention. (Some com- and that a or a seamless leaden gasket made from wire is drawn back to the machine, comprest nto pressors have this head cast solid without Remove the unloading lever and solder, is used. Leaden gaskets are best a liquid and allowed to lose its load of unloader.) against heat being trans- have the opening carefully welded, care and may be used with assurance heat in the condenser; the leaks caused by vibration. ferred to and carried off by the cool ng being taken to get no metal into the unload- water. The refrigerant is then ready to ing valve, which might prevent it from (Continued on paye 1096)

Condenser&Tank Compressor

7 ---Oil hole

bWieti,1. Bearing covert Flange with 41111111111-d ll screen - D- Bearing ;Oil gauge -Comp. wall z`pipe tubing Safety Ex.li y. cap; Packing valve'

Oil fi er 014,.E ' ` New Angle valve To can f J Screw of water an Purge

-13- - E- Ì -C- Brine- Tank refrigerating machine for home or details are given in the above illustration. and accompanying text by an expert, for building an electric Complete in their complete form, and are, therefore, out of the reach of the average laboratory use. As tle commercial machines cost several hundred dollars for about $100.00 or less, will no doubt prove of extrem' interest and value. The ice machine here shown, can be assembled householder,-A-e. this article his article. as the author points out in

1075 The two diagrams above show how to arrange the camera, reflecting screen and subject, before houette photography. Several excellent the window for both portrait photography and sil- examples are shown above of photo -portrait studies, including silhouette and shadow photography. Now ec ur . Y ERNEST BADE

PART Ill-PORTRAIT PHOTOGRAPHY

APERCEPTIBLE adverse influence far from being artistic, although they are If it is a has been felt for some years in portrait which is desired, then por- only too often considered as such. the background must trait photography, the direct cause The personal be quiet, it should be peculiarities of the poser of such nature that it lies between the being traceable to the retoucher's must be brought forth high- brush. in portrait pho- est lights and the deepest shadows. As a The photographic process is tography, otherwise it does not tell us any- not so incomplete rule the light requirements are amply pro- as to make this a necessity, thing it then being only a cold immobile vided in fact, no negative ought to for in the modern dwellings with its be retouched. reimpression of nature. Every landscape large windows, If it is done, it is a sign of the lack of especially if a very sensitive changes its character, it is different in the plate or film is used. Then photographic technic. Retouching spoils early morning hours than an exposure of the negative, when the sun a few seconds is sufficient to secure good and although it may often be well rides high in the heavens, far different in to fix smaller plate or film well developed negatives. But here it is im- defects such as early afternoon than in the hours of twi- perative to tiny holes, etc. These, when blackened, show light, somewhat lighten the side of different in summer and different in deepest shadow by reflectors of white on the print, and it is this print which winter. And as nature has its white paper is most own moods, or cloth. Mirrors are not so well adapted easily treated. Should the defec- so are the moods of man comparable to the tive part consist of black for this purpose as they reflect too much spots and pin seasons of the year. The only time a suc- light making certain points, they can be removed by carefully cessful portrait can parts stand out too rubbing be taken is at a mo- prominently. with the point of a needle. ment of relaxat;^n and rest, then the char- Artificiality in lighting effects, while tak- acter of the poser Artificial lights, such as electric or gas ing poses, is easily read in his face. mantle lights, have practically been eliminated, A self-conscious picture a are suitable for portraiture. because with conventional But here it is they tend to produce unnatural and grin is worthless, the face and essential that a very good lens, forced facial expressions. the expres- allowing much light to pass Photos are de- sion are distorted, it is a mask but not a through it, is sired, in fact demanded, which show life, portrait. used and also the employment of more individuality, than one source of light character,-peculiarities de- Groups and portraits are taken to the is requisite. for stroyed by the retoucher's brush. The origi- only then can the hardness of the photo be best advantage in an indirect light, such as softened. nal negative should not be touched. All of can be found both The lights must be placed quite the many in morning and after- near the person knacks brought to bear upon it for noon hours, the rays then being lateral. to be taken and so arranged the production of an artistic positive, are When that one illuminates the subject while the the sun is hidden behind a cloud, other softens employed while enlarging, but mistakes both the light will also be perfect the shadows. Care must be in lighting for this pur- taken that the and developing, cannot be wholly pose, as no sharp shadows are cast. A pic- direct light from the lamps rectified. The proper lighting, the emphasis does not enter the lens of the camera. If ture taken in the open requires a careful se- the source placed upon certain parts and the repression lection of the background. of light is quite brilliant, an ex- of others If the latter is posure of a few seconds which may detract from the value too sharp and distinct, with many high and will be sufficient. of the picture are problems which must be low lights, Such plates must be developed in a rapid solved before the person will be lost in ob- developing bath. the photo is taken. Pictures scurity, it should be of the severest sim- whose subjects are all out of focus are plicity and be placed in the shadow. (Continued on page 1106) 1076 Electr static to LC. Converters y CLYDE J. FITTCH

THE conversion of alternating cur- A simple condenser, of large capacity, that practically constant. The voltage across ter- rents into uni -directional currents of will stand a potential up to 150 volts can be minals A and B is pulsating, the maximum small amperage and at high voltage made by immersing an aluminum plate and value of which is equal to twice the maxi- is most easily effected by means of an iron strip in a solution of sodium phos- mum value of the alternating circuit voltage, the electrostatic converter-a com- phate; the aluminum plate constitutes one and the minimum value is equal to zero. bination of rectifiers and condensers. This side of the condenser and the electrolyte The action of this converter may be ex- constitutes the other side. The iron strip plained as follows: Suppose the converter type of converter is so easily and cheaply the constructed that it is surprising it is not is merely an electric connection to the elec- is connected to_ a. 110 volt A.C. line, and more popular, especially among the radio trolyte. If the aluminum plate is 6" by 6" current of the first half cycle flows down the condenser will have a capacity of about the right hand -wire. This will charge the enthusiasts. the iron 6 The aluminum plate is con- condenser to the maximum value of If a strip of aluminum and a strip of microfarads. 110X V2 are immersed in a solution of sodium phos- nected to the positive side of the line, and A.C. voltage, which in this case is phate and connected to an alternating cur- the iron strip to the negative side of the or 155 volts. The current of the next half line, if used on a D.C. circuit. If the con- cycle flows down the left hand wire, but this rent circuit, a microscopically thin film of rectifier oxide forms on the aluminum strip. This denser is to be connected to an alternating current cannot flow through the film has the peculiar property of allowing current line two aluminum plates are used from the solution to the aluminum, opposite current to flow through it in one direction, in place of one aluminum plate and one iron the direction indicated by the arrow, so but not in direction. The current strip. the current flows from terminal A, through the other to B, and then the Figure 1 shows the simplest type of elec- the external circuit terminal will flow from the solution through side of film to the aluminum strip, but not from trostatic converter. This converter con- through the condenser to the other the aluminum strip through the film to the sists o a rectifier and a condenser and the A.C. line. Therefore the condenser, solution. This makes the active element of they are connected in series to an alternat- which is charged to 155 volts, is discharged reliable rectifier, and ing current line, with terminals brought out through the external circuit in series with a very simple and is will be used in most of the following cir- at A, B, and C. The direct current may be the A.C. line, whose maximum voltage cuits. taken from either terminals A and B, or 155, so that at every other half cycle the Another important feature about the rec- terminals B and C. The voltage across ter- voltage across terminals A and B is 2X155 tifying film is its high electrostatic capacity. minals B and C is equal to the maximum or 310 volts. The polarity of the terminals The film is so thin that it forms an excel- value of the alternating circuit voltage, ne- will be as indicated. lent condenser dielectric, for storing up an glecting losses; and if the capacity of the The actual D.C. voltage, is about 87 per cur- cent of the theoretical valise; the losses are electric charge. " The capacity of one square condenser is large and the amount of inch of this film is about 0.09 microfarad. rent withdrawn small, the potential will be (Continued on page 1102)

110 V. A.C. Line 110 V A.C. Line 110 V A.C. Line Aluminum strip Aluminum plate t

FIG 2

C FIG.3 8 Mfd condenser r Aluminum 110 V. A.C. Line FIGA Iron-

ChoKe coil

A C 465V. D.G. Glass jar- B

D Aluminum

2 Mfd condenser FIG.6 L T 110-220 l' vibrator, ChoKe coil 50 W. trans'. Clamps Ironisupport fi Air gap AC.

m CD,

575 V D.C.

FI . CHOKE COIL FIG.7 FIG.9 currents of small A number óf interesting and novel circuit arrangements are shown above, for converting alternating currents into uni-directional use of the "electrostatic converter"-a combination of rectifiers and condensers. The rectifier units may amperage and high voltage, involving the phosphate. These be of the V. T. type, or electrolytic units employing aluminum and iron plates immersed in a suitable electrolyte, such as sodium circuits will be found valuable to radio men, and Mr. Fitch has used them for his radio set with gratifying results.

1077 HOW - TO -MAKE -IT

This department will award the following monthly prizes: First prize, $15.00; second prize, $10.00; third prize, $5.00. The purpose of this department is to stimulate experimenters toward accomplishing new things with old apparatus or old material, and for the most useful, practical and original idea submitted to the Editors of this department a monthly series of prizes will be awarded. For the best idea submitted a prize of $15.00 is awarded; for the second best idea a $10.00 prize, and for very the third best a prize of $5.00. The article need not be elaborate, and rough sketches are sufficient. We will make the mechanical drawings. Use only one side of sheet. Make sketches on separate sheets.

FIRST PRIZE, $15.00 SECOND PRIZE, $10.00 were fixed; one of these clips was weighted. It will take a bit of experimenting to find CAMERA DUPLICATOR shifted, it is relatively impossible to dis- the best weight to use; I used a twenty -gram Ordinary duplicators for cameras turb the camera on its tripod, as would weight. It should be light enough, so that when film is work very well, but one which I re- be the case if the duplicator had to be the traveling down, the weight cently built was found far more efficient turned around to make the picture. The

,,,1.111111111111111111111111111111111111111:111,111.1.

Photo at left shows re- markably clear double exposure made possible with the novel camera duplicator, her e de- scribed by Mr. Lennox. Both of the figures in the picture represent the same man about to roll over himself with a lawn mower.

,.111111111.11111111111111.11101.0111111111111L1111111111111 Fig. s than modern duplicators now found One view of home-made device for devel- upon diaphragm should be stopped down oping roll films. the market. A metal cap to fit the lens slightly for better results. of the camera has two slots cut into it, -Contributed by W. F. LENNOX. of the ascending as shown in the accompanying illustration. film and clip just counter- The barrel portion balances it. This is so that when the film is which fits over the GREASE GUN released, it will not drop lens is slotted, so that the and splash in the cap can be secured A round bottle tray, but slide down and slowly halt just as rather firmly. Two small lugs are soldered of a size according to the to choice of the user as in A is the first re- the other end is at its highest point. With opposite ends of the barrel midway be- this apparatus, only one tween the arched slots, quirement. Take a glass -cutter and cut hand is required, and a vane Qr shut- and that only moves in ter is pivotally off as close to the bottom as possible, then one direction. mounted between these lugs, make so that it flipped a plunger of wood as in B to fit as I tacked a small battery motor on the old can be to either one side or tight as the other. possible in the bottle. Then to use frame, and fastened a movable lever with its idler pulley, as shown ill Fig. 2, operating \Vith equal exposures, first with the this on the same principle as the clutch on subject in front of the opening in the the old belt -drive motorcycles. I fitted the con- cap on one side, and then with the shield trolling arm with a string, trusting to a thrown over in the opposite direction rubber band to pull it back. Pulling the opening the opposite side, the subject string would connect the continuously run- changing his position, photographs such ning motor to the film -string, causing the as shown herewith, are possible. Notice film to walk right up, releasing the control- particularly the fine definition in this ling string slightly would throw the motor photograph and the absence of a divid- out and Mr. Weight would accompany Mr. ing line between the subjects. The de- Film down again. vice can be operated very speedily, and Contributed by CLARENCE P. SALMON. due to the fact that the vent is easily This home-made grease gun will be found handy around automobiles and other machinery. the bottle as a grease gun fill the bottle with the hard oil and put the small end of the bottle in the place for the grease to be placed, then put the plunger in the bottle and push down thus forcing the grease out. To use it as a sausage stuffer do the same as in using the grease gun. This same bottle may be used as a funnel as in figure D also. Contributed by \VM. LINDEMAN. THIRD PRIZE, $5.00 ROLL FILM DEVELOPER Photography is one of my hobbies, and see-sawing films through the air is as tire- some to me as anyone else, if not more so, on account of the position of my developing table. So one afternoon, before developing, Fig. This picture shows the camera duplicator I arranged an apparatus such as shown in which fits over the lens. This duplicator Fig. 1, out of my builder set, and hung it Second view of home-made roll film devel- results in very fine definition in the double on a trolley oper, which is actuated by a small battery exposure, as is evidenced by the photo -like arrangement over the de- or other motor, in the manner shown. The reproduced above, the dividing line veloping table. The string -belt, motor drives the rocking arm through a tween be- which the two half exposures being in- passed over the three pulleys terminated in belt, tightened or loosened by means of an visible. two hooks, idler pulley, operated by the controlling to which the filin clips and film string shown. 1078 EDITED BY S. GERNSBACK MAGIC CHEMICAL COLOR THIS MONTH'S $5.00 PRIZE DRILLING GLASS seen in your magazine and others so CHANGING I have half full of water, put HOW TO MAKE YOUR OWN SAL many pitiful attempts to describe methods In a test tube for sheer pity about 2 c.c. of phenolphthalein solution. AMMONIAC for drilling holes in glass that audience. I am going to tell how it is done profession- Exhibit this milky liquid to your ally. This is a trade secret but-radio Then drop a good sized pinch of sodium Without doubt most of the readers of which turns it red. the ordinary sal youth must be served. carbonate in the solution, this magazine have used Now if the same amount of copper sulphate ammoniac battery in their experiments. I have drilled as many as 100 holes per i is dropped in, it turns purple ; but if shaken a blue color results. A large pinch of Glau- ber's Salt (sodium sulphate) turns the blue Small to dark green. Next drop a good sized pinch G' L' I, hole of sodium bisulphide into it, and a brown color results. Then if that same quantity of 1 tartaric acid is added, the brown turns to Wet dark green. Add still another pinch of the E. string acid and a beautiful light green is formed. A pinch of iron sulphate is added, but noth- ing happens. Then if a few crystals of po- tassium bichromate are dropped in the so- lution, nothing happens until the mixture is stirred, when it turns back to dark green again. It cannot be shaken because gas is Fig.4 Fig.2 liberated. The mixture is liable to boil over, so it is best to perform the tricks over a With the simple apparatus set up as shown above, it is possible to make your own sal ammoniac. newspaper spread on the table to prevent Diagram in Fig. 2 shows how to cut off base of incandescent lamp in order to make container A. soiling it. Some have possibly also made their own hour in opalite-so hard that an ordinary Contributed by D. R. HOAG. batteries, that is, everything except the bat- glass cutter will not touch it. Many holes tery compound. The following description are only one -quarter of an inch from corners THE MAGIC KNIFE will tell you how to make your own sal and I never crack a glass-while drilling. half full of water, put three on the drill In a glass ammoniac. Nine -tenths of success depends grams of sodium bisulphate, and when this and one-tenth on the manner in which it is In the diagram, Fig. 1 (A), is an incandes- has been dissolvedput in another glass half cent lamp bulb with the plug removed. The used, both of which I describe. full of water, three or four drops of phe- plug may be removed as follows: File a nolpthalein solution. Rub your arm with a small hole in the glass near the plug, which Motion of Brace sponge soaked in the first solution, and must be done cautiously, to admit the air. moisten the knife with the second solution. Then wind a wet string several times around You are now ready for the experiment. the glass just above the place where the bulb Viciously (but carefully), slash at your arm, is to be severed, as illustrated in Fig. 2. snaking sure that the flat part of the moist- Then run a hot piece of metal around the Grind off end of tie ened knife comes in contact with your wet lamp between the string and the plug. The arm. After a few moments, the audience will glass will then crack in a straight line all like geld smooth see a reddish substance, blood, cover- the way round. With a slight blow, the plug ing the supposed slash. off. will fall Contributed by JOSE R. DEL GALLEGO. In Fig. 1 (B), is a rubber stopper with three small holes (not too small), and C and IODINE DROPPER C' are two bent glass tubes which pass A simple way to make an effectual through B. The two vapors enter the bulb dropper for the iodine bottle is to use an through these. A straight glass tube D, old electric light bulb for this purpose. passes through B, between C and C'. It Break all of the glass away with the excep- should extend about three-quarters of the tion of the central solid glass stem, and see way down the bulb. This tube allows the ex- that all the wires are removed from this. cess air and gases, which are harmless, to Illustration above shows how file is ground to make drill for use in boring holes through Now slip a rubber washer over the same,,so escape. The bottles E, and E' contain muria- glass, also method of using brace and drill. that it fits against the screw plug tightlq, tic acid and ammonia respectively. Of the and then wind several layers of friction tape other parts, F and F', are two -holed rubber Procure a 3 -cornered file and dress as per around the top to act as a cork. With this stoppers, G and G' are two bent glass tubes cut, on an emery wheel, turning very slowly dropper, wounds can he treated without soil- which are connected to C and C' respectively and removing file very often, so the point ing the hands. by rubber tubes H and H', and L and L' will not burn and lose its temper. Contributed by H. W. JACKSON. are also two bent glass tubes, on one end This shape throws the point off center, of each there being attached a plumber's which is the successful secret of the drill.

furnace bulb. The other ends dip almost Sharpen the bevel point . often and merely to the bottom of the liquids. touch up the long sides, on a fine oil stone. A small stand for thé lamp bulb may be Fasten the drill in a common carpenter's made as follows : A piece of large gauge brace, place the point on the glass in a drop copper wire, about No. 8 or 10, is bent into of turpentine and spin it with the hand on a loop to fit the bottom of the bulb. Then top of the brace and the offset handle as a bend the remaining piece at a right angle counterbalance. The slower you spin it the and insert the end in a base. faster it cuts; you cannot use it in an electric One thing is certain that to make the ex- drill. periment work right, all joints must be tight. While it is spinning, the hand describes Now by pressing each of the plumber's bulbs a circle about one foot in diameter, which is simultaneously and with equal pressure, an the second secret, as this method makes the equal amount of each of the gases enter the hole larger at the top and the off-set point takes care of the bottom in like manner, so tube. As the gases mix in the bulb they is the cause unite to form sal ammoniac, which will your drill will never bind, which gather on the sides and bottom of the glass of breakage. Incidentally, this drill is better for bakelite Handy iodine dropper for the laboratory or in white flaky crystals. When the bulb is and hard rubber, etc., than a regular drill. home use, made from the base and glass stem full, scrape it out and proceed as before. of a discarded incandescent lamp, the glass Contributed by RAYMOND EKLUND. Contributed by W. M. ROCKWELL. being broken away with a pair of pliers. 1079 AN important d n of periments which are now being conducted generating locally at the receiving set a oceanic radio telephony occurred and those which are scheduled to follow, use small high frequency current, which corre- Sunday evening, Jan. 14th, when H. is being made of these improvements. sponds in frequency to the suppressed waves. B. Thayer, President of the Ameri- One of the developments which has been can Telephone and Just what is provided by the new system Telegraph Com- in progress since the telephone company's of radio is pany, speaking at the offices transmission clearly shown in. of the Company, demonstration of trans -oceanic radio tele- our diagram which should be read from 195 Broadway, New York left City, was heard phony in 1915 has to do with the perfection to right. The speaker's voice supplies a by a group of well-known electrical engi- of high powered vacuum tubes. The tubes neers and others assembled band of speech waves extending from the at New South- used in the present tests are characterized frequency 200 to gate, a suburb of London, of about 5,000. A vacuum England. The by a large external anode which is cooled tube oscillator supplies a transmission by radio high frequency telephone was declared by water. By virtue of water-cooling each wave the so-called carrier wave which, for by all who witnessed the test to be in every tube can readily handle as much as 10 kilo- the way purpose of illustration, we have taken satisfactory. The radio apparatus and watts of power. at 50,000 cycles. Before modulation system used in this test have the been made pos- In the present installation, which is located speech wave and the carrier w -.ve are en- sible by co-operation betwen the American at the large station of the Radio Corpora- tirely Telephone and distinct. After modulation we no Telegraph Company and the tion of America, at Rocky Point, the final longer have any speech waves as such, but Radio Corporation of America, and are the stage of amplification comprises a group we have two new sets of high frequency result of research and experimental work in of 20 of these tubes operating in parallel. waves, one ranging from 50,200 the up to 55,000 laboratories of the A. T. & T. Company The output of 100 kilowatts is delivered to cycles and the other from 49,800 down to and in the laboratories of the Radio Cor- the antenna and, due to a new system of 45,000. These two new sets of high fre- poration of America and its associated com- radio transmission employed, is as effective quency waves are known panies. as the side bands. as 300 kilowatts would be in the systems In the usual radio telephone transmitter In 1915, engineers of the A. T. & T. Co. commonly used. In the systems commonly both side bands as well as the carrier wave succeeded in talking by radio telephone from in use about two-thirds of the energy goes are radiated out into the Naval the ether. Approx- Station at Arlington, Virginia, into waves other than those which comprise imately, we may say that in these across the Atlantic to systems Paris, and the same the message, these waves being needed by two-thirds of the high frequency energy is messages were heard 5,000 miles to the west- many of the receiving sets in use for detec- assigned to the carrier wave and one -sixth ward at Honolulu. Since then great improve- tion of the message. The new system sup- to each of the side bands. ments have been made in the two arts of presses the waves which do not comprise the radio telephony and telephony. In the ex- message and reception is accomplished by (Continued on page 1133)

»Ardcre.7.7.c 039r . A

=E- 70 MILES PRELIMINARY 'RADIO AMPLIFIER !STATION REPEATER REPEATER REPEATER ¿aR EAST RIVEN ;RQCKY PORT JEFFERSON FARMINGDALE PUINT JAMAICA BROOKLYN stPeEi ï.r.9-.C._gYc'. ,s.ré+TEMA As POLE LINE UNDERGROUND CABLE ! ,( ;r IIFAfï Igo ., , Z tl tl It 2-IOI.W. TUBES `-- ü i1

w1ReERtr éeeRRe 3 STAGE `-... *toes AMPLIFIER Ì OSCA LATOS ! WTltf AND MODULATOR -4211

20 TEN N.W. warts COOLED TUS

100 K.W. TO ANTENNA

NEW SOUTH GATE ENGLAND

t,

© i923 BY SCIENCE AND INVENTION

When the human voice was projected across the Atlantic the other day, from the twenty-sixth story of the American Telephone and Telegraph Coln. pany's building, in New York City, to a building located at New Southgate, England, the powerful vacuum tube apparatus illustrated above, was brought into action by the weak voice currents of the speakers in New York City. Return speech from England to America was not demonstrated, as the proper apparatus had not been shipped across the ocean in time, but a number of important and interesting tests were made in the transmis- sion from America to England. The various links in the combination wire and wireless circuits, are clearly shown in the photo -diagram herewith, thanks to the courtesy of the company who made this remarkable feat possible.

1080 .. ...:.®.:. 4:.

LOOP t RADIO REC. SET

SIGNALS RECEIVED UNTIL DOOR WAS SHUT TIGHT BANK VAULT - I2». WALL, STEEL, CEMENT AND ASBESTOS ON ALL SIX SIDES

OROOKLYN

IÜ4til1l 111 1131,11;1112!:"::

concerts, receiving apparatus and loop aerial employed in successful reception tests of radiophone broadcast The photograph at left shows the actual waves are shown as well as the space waves above while under East River, passing from Brooklyn to New York City. The ground on tube train the ground and water. To Mcw.§i:f

interference by induction from ASUCCESSFUL demonstration of the satisfactory and that near -by broadcasting considerable be heard with perfect clear- passing trains, as well as from the motors , stations could practicability of receiving radio the set. messages underground, despite in- ness in the tunnel when the conditions in it on the train carrying tervening steel construction and in- were favorable. He said that there was A little later on a very interesting test was terference due to induction from made in a large sealed vault of the Inter - other electrical apparatus, was made recently TRI COIL' R.F TRANSF borough Rapid Transit Company, when the in the subway. Not only were messages re- same receiving set, a diagram of connections successful ceived all along the line of the subway CRYSTAL of which is given herewith, was tunnel, but part of the concert being broad- DETECTOR in picking up radiophone broadcast messages casted by WEAF, at the station at 24 Walker inside the steel walled room, up until the New York City, was clearly heard in point where the heavy safe -style door was Street, _0005 MF music and the middle of the tube under the East River, Y almost closed. The radiophone half way between Manhattan and Brooklyn. talk proceeded until the opening in the door The radio receiving set, which is the in- would just permit a piece of writing paper vention of John Clyde Davidson, a radio to be placed between it and the door frame. finally sealed and locked, engineer, was placed on the rear platform of 2 When the door was the radio music ceased. a regular train, which started at Atlantic 3 Avenue, Brooklyn, and ran to the other end Off hand, it would have seemed that even of the line in the Bronx and back again. 4 with the steel vault door open, there would by the steel The door leading to the rear platform was POTENTIOMETER have been sufficient absorption closed and, as head phones were used for walls to prevent the operation of the radio receiving, few, if any, of the passengers AUDIO FREQUENCY TRANSE receiving set within it. This philosophy knew that the test was in progress. v would also seem to have come into effect in A loop aerial four feet high and two feet the subway experiments, where the receiving wide was used in the receiving set, which, set was practically enclosed with the steel although only eighteen inches long and seven shell of the car, and also within the steel and inches wide, was equipped with a radio and concrete subway tube. It is possible, of under the audio frequency circuit. W. H. Kinlock, 2 course, in the subway experiments chief telephone and lighting engineer for the river, that induction currents or waves were 3 the from land Interborough; F. E. Heger, his assistant; 4 carried along through subway TO LOUD SPEAKER' by the two running rails, the insulated third E. L. Bragien, a radio expert of Manhattan, 60-100 VOLTS and David H. Engelson and Jesse Fishel, rail, or possibly by the pipes and wires run- were present at the test, which was in charge Hook up of radio frequency and audio-fre- ning along through the tube, and that the quency V. T. amplifiers, as well as crystal de- radio set on board the train picked up waves of the inventor. tector used in receiving radio broadcast con- Mr. Kinlock said that the test was very certs in tube train under river. by induction from these rails or pipes. 1081 in : _ t t y A. Po PECK

editorial staff of the World, "by making the receiving cylinder revolve a minute fraction of a second slower than the sending cylin- der. At the end of each revolution, the latter stops, and a current of the opposite direction to that formerly employed, is sent out for the same fraction of a second. By means of this current the rotations of the two cylinders are synchronized. Thus, at the beginning of the next second, both the , transmitting and receiving cylinders will be in perfect synchronism." While it takes some time to describe this action, still the reader must realize that it all takes place in a very small fraction of a minute. Since such perfect synchronism is neces- sary, the cylinders are controlled by elec- tric chronometers at each end of the line. When the operator at the transmitting sta- tion desires to communicate, he sends out automatically, by means of his chronometer, dots corresponding with seconds. These are picked up by the other operator, and his chronometer is automatically set in ab- solute synchronism with that at the trans- mitting station. All this accuracy is neces- sary, for, if there is the slightest amount of lag in either the transmitter or the re- ceiver at any time, the resultant message will be a mere jumble of dots. The photograph above shows the Crypto apparatus, and "A," the cylinder upon which is mounted the photograph or message to be transmitted. "B" denotes the Crypto discs, and "C," the pawls This synchronism between the two sta- which close contacts as the discs revolve. tions is made use of by M. Belin in his Crypto or to quote Mr. Benington, "the FOR years the development of radio graphs by wire, and his Crypto has been ap- anti -capturer". As explained to the writer has been hindered by the fact that plied to this work. The New York World by M. Belin in a recent interview, the messages sent out could be picked up has purchased exclusive rights to the ap- Crypto regulates the revolutions of the cyl- by anyone equipped with a receiving paratus for transmission of photographs by inders in such a way that while the trans- set. Obviously this was a disadvan- wire, and will use it extensively in their mitting cylinder is revolving, the receiving tage in commercial enterprises, as well as in work. cylinder is revolving also, and when the times of war. Various subterfuges, such as The Crypto cannot be applied to ordinary former stops for a fraction of a second, the high speed transmission and reception by radio communication, but it can serve its latter does the same. The intervals of rotation machine, have been used with greater or purpose in this work . by transmitting a which, themselves, are always of the lesser success, but it has been left to M. photograph or fac-simile of the message same length, are interspersed with periods Edouard Belin to by Belin's process, and using the "Crypto of quiet. These latter can be readily con- solve this problem, and trolled, he has done it in a very simple, yet posi- in connection therewith. In the standard ap- so that thousands of different paratus that does not use the Crypto, the "codes" are possible. tive manner. The Crypto M. Belin is the inventor of the known transmitting and receiving cylinders have consists in the main of six well to rotate in perfect discs mounted upon an axle about of apparatus for the transmission of photo- synchronism. "This is 1/12 obtained," writes Arthur Benington of the (Continued on page 1134) A simplified diagram of the Belin apparatus for the transmission photographs I SEC. of iSEC I by wire or radio, SEc_ I sFc.---"---C--. together with the "Crypto," is here given. For ------,-- Ië'-v---- greater simplification only three of the six Crypto discs are shown. The main shaft which is turned, by a motor, connects through a friction transmis- , i I i i E SEC ¡ 30Z0 VIC. SEC SEC I sioh with a gear which drives the Crypto discs; a e SEC. SEC. controlling wheel; the gear which turns the cylin- der; and also a "static disc" which sends out manu- SEC. SEC. SE . SE C., ,SEC. factured SEC. 4 I IS/PC 541°C interference so as to prevent reception of 11 SEC. 1%0 3o EC the message in case anyone should possibly stum- e30 / SEC eY30 SEC. ''->/xx SEC. ble upon a method of translating it. This is labelled CODE "static disc." By means of the synchronizing Nº. 687.943 clock and its attendant relays and battery, the speed of rotation of the disc M and *consequently STATIC DISC -- of its shaft, is kept in absolute synchgonism with that in the receiving station. The disc .M revolves one turn in 59/60ths of a second, but it is held until the end of that second by the tooth G, whereupon it is released by relay No. 2. The Crypto discs are driven at a speed (TURN PER SECOND- of 1/6th revolution per second, whereupon each disc controls one revolution of the cylinder, by means of the contacts C; the battery and the elec- tro -magnet. The cylinder is driven through the magnetic clutch at a speed of one turn in 2/3rds of a'second. By means of the lever H and a slot in the disc J, in connection with the contact B, the magnetic clutch is opened and closed. By means of the contact D, which closes when the MAGNETIC CLUTCH clutch is closed, the static disc or interference manufacturer is short-circuited and' the actual mes- CRYPTO DISCS., sage or photograph is sent by means of the relay marked IC to the radio transmitter. When the RELAY Nº.I clutch is opened, the contact .F is opened and closed by the indentations on the static disc, send- TURN ing out independent signals to create interference. PERSECOND- At these periods the contact A is closed because FRICTION of the fact that the contact on the message is rest- TRANSMISSION ing in an indentation in the cylinder. In the insert is shown a schematic diagram illustrationg graphically the periods of rotation of the cylinder which is upon mounted the photograph to be -CONSTANT SPEED transmitted, together with the spaces of varying MOTOR lengths between these periods. uunnnnnnnnunnuunnnnnnuuunnuuumunnmunuunnnunnwnununnunuunnanmmM®uM» 1082 © Mica diaphragmQ

I `7nn . ! .,. o rro

' ; í o I ol_\\ ____ , ,! Clamp i ' --- __ FIG.1 - - - " Iron armature vibrates TOP VIEW TOP VIEW TOP VIEW Soft iron U=Shoped 3 Pole pieces` le ieceQ FI Diaphragm® ,Po P Soft P ieceS , , inlindin 4 Soft iron I 7 Q2 g . _L pole piecesironpole pole pieces Winding . ; \ . QeWi ...... _/s I6^l ... .. $ `' ',1e m9. ''11 0 I r.... ' Y Islimm\ .-. t' Ir gg :_: -2: / ! Winding . Hard steel magnets Q3 Winding ` \ \ ©% Ff steel magnet Hard steel magnets QHard FIG.2 Hard steel màgnet

Fig. I at left shows one of the latest type radio receivers, having three poles with a magnet coil wound on the center one, giving a very even and well distributed pull on the diaphragm. Fig. 2 shows the "insides" of a well-known.. double -pole type radio receiver, the two poles being of opposite polarity. Fig. 3 shows one of the newer types of radio receivers having four poles of alternate magnetic polarity. A very even and powerful pull is obtained frone this design, and more ampere -turns in a given space are possible, so the makers' claim. Fig. 4 shows the "works" of 'the famous Baldwin receiver, so widely used in building loud -talkers, etc. This phone, owing to the lever arrangement connecting its diaphragm with the light iron armature, suspended in the center of the magnet coil, has a decided amplifying effect. t e y A MST NG PERRY HOW TO SELECT A HEAD SET MY first telephone was a single 75- heavier than some others and that is a dis- springs could be bent without injury I suf- ohm ear -piece that cost seventy- advantage when it is worn for three or four fered more or less from the tight pressure five cents plus half a dollar for hours at a stretch, because the weight is of the ear pieces on my skull. An opera- a leather -covered steel spring to tiresome until you get used to it. tor showed me that by working the springs hold it on my head. I still use The up-and-down adjustment is a great carefully, bending them a very little at a it sometimes for comparison with others. improvement over that on the cheaper phone time at each spot along their whole length With from fifty to one hundred feet of an- and it has been adopted by a number of and avoiding a sharp bend at any one point, tenna wire, properly installed, the usual manufacturers. A rod attached to the ear- I could adjust them so that they would be ground connection through a steam radiator piece slides in a hole in a piece of metal at- neither uncomfortably tight nor too loose. or water pipe, and a crystal detector I can tached to the head band. The pressure of During the past year I have tried several hear most of the local broadcasts in any of the springs that hold the ear pieces against of the new phones. Most of them use a the several cities where I have tried it. If the ears is sufficient to keep the rod sta- 1/ -inch metal diaphragm and magnets dif- the room is quiet I can hear the music, tionary wherever it, is placed. Either ear fering but slightly in construction and ap- speech and code with satisfactory distinct- plication fram those of my second pair. ness. Such an outfit costs less than ten nnin11111 iiiunnaunnu1uuiiiiuii.111111iiiiiiiiiiiiiiiiiiniiiiinuiiiiiniiiiiiiiiiiiiiiiiiiiiin1111.1inuni in3 There are sometimes noticeable differences dollars even at the present prices and it Some of the Interesting Articles in results that seem to be due to better or would satisfy, at least temporarily, any boy Appearing in poorer engineering or workmanship. A of ten or twelve who was not discouraged by the March Issue carelessly constructed phone usually reveals the contempt that persons who are able to of RADIO NEWS its character to the eye if it is examined own better apparatus sometimes show to closely but of course a test under the be- others less fortunate. ginner's home conditions is the surest means Experiments With When I reached a point the Two Plate Con- of discovering what it will do. where I wanted denser Antenna. By John C. Warner. something better I bought a double head set One pair, bearing a foreign trademark, of 3000 ohms resistance, paying $5.50. The A New Non -Interfering Detector has diaphragms 2% inches in diameter and same general type of phone is produced by Tube. between the diaphragm and the part, on a number of manufacturers. The dia- which it rests, is a thin metal ring. The phragm is metal. It is actuated by a magnet The Radio Flivver. By Stanley Edgar. music or speech heard through this set gives which can be seen by unscrewing the cap the impression of being somewhat weaker and removing the diaphragm. This set has A Selective Multi -Range Regenerative than it is when phones with smaller dia- given good service for several years without Receiver. By Kenneth Harkness. phragms are used, but it has roundness and appreciable wear. Its only serious fault is sweetness that none of the others can equal. that the head band is so constructed that Broadcast Reception and Receivers. Now in the selection of phones, as in the it invariably pulls my hair when I try to By John Bront. selection of any other part of the equip-. adjust it to my head or take it off. ment, the beginner needs to consider what Electron, Electric Waves and Wire- use they have. Then there came a time when I wanted less Telephony. Dr. will Usually the manufac- the best phone regardless of price. The By J. A. Fleming. turer and dealer rate a phone by its resis- testimony of everyone I asked favored a The Construction of a Loop Aerial. tance in ohms, which depends upon the ma- certain phone with a mica diaphragm. I By D. R. Clemons. terial, size and length and material (unfor- purchased a double head set for twelve dol- tunately) of the wire in the electro -magnet lars, a price that was promptly increased as that actuates the diaphragm. The 75 -ohm soon as the general public went in for piece can be moved up or down with one phone may not respond at all to a weak cur- radio. I found that this pair would bring hand in an instant. Some other phones using rent that will produce satisfactory audibility in stations that I could not hear at all with similar head hands and attachments have in the phone with a mica diaphragm. On the less sensitive phones. The reason seems to setscrews for fastening the ear pieces at the other hand I made one test in which a fifty- be that the diaphragm is thinner and there- desired height. This may be an advantage five cent phone gave just as good results fore more easily vibrated, and that the pull when the phones are being used principally on code signals from a high power station of the magnet is applied through mechanical by one person and the operator wants to near at hand as the pair that I paid sixteen members that help to produce an amplitude put them on and off frequently, for it saves dollars for. If what I wanted to hear of vibration much greater than usual. The a moment of readjustment each time they came entirely from the high power station manufacturer's claim that this phone gives are put on. I would save the fifteen forty-five. Also, as much increase of signal strength as one The head bands are bent into a small if there were young children in the house, stage of audio frequency amplification is ap- circle so that the set can be shipped in a I would provide them with a cheap and parently true, though I have not tested it smaller box than would be necessary if they strongly constructed phone rather than to with mathematical accuracy. This phone is were more extended. Not knowing that the (Continued on page 1135) 1083 Top photograph shows amplifier described below connected to a standard three circuit tuner. Lower left: General rear view of amplifier. Lower right: Bottom view of amplifier showing transformer and socket mountings. lifi r for r sent Tun r ERT T. B®NAV ikrru

RADIO frequency amplification at space of time. The writer has had several detector circuit and one in the second stage present is quite the rage, and not unsatisfactory experiences of this nature of audio frequency amplification. When the without reason is it so. Many, no with the now famous New York "gyp" telephone receiver terminals are plugged into doubt, would like to build an am- dealers, and has decided that dependability the first or detector jack, the filaments plifier for use in conjunction with over -balance low cost by far. of the two amplifier tubes on the right are their present tuner, that would incorporate Apparatus Required extinguished, as they are not in use. When at least one stage of radio frequency am- 1 Bakelite panel, 7 by 10 by a inches. the second jack is plugged into, the entire plification. It is with pleasure that the 4 Sockets, preferably of the panel mount- power of the amplifier is being used. If writer submits the following design for such ing type. the plug is removed from this jack, the cur- an amplifier. It is the last word in compact- 4 Rheostats, also panel mounting. rent is transferred to the output terminals ness, occupying a panel space of but 10 by 1 Potentiometer (200 to 400 ohms). to which the loud speaker is connected. It 7 inches and extends only 7 inches deep. 2 Audio frequency amplifying transf orm- is the opinion of the writer that a jack in The one stage of radio frequency amplifica- ers. the first stage audio is not worth the trouble tion is of the tuned plate impedance type, 1 23 Plate variable condenser. of wiring and the extra cost, the call for recognized as the most efficient method of 3 Mica condensers (.001, .005, and .00025 its use being limited. If signals are too radio frequency amplification. The compact- microfarads). loud on two stages, the tuner can'. be ness in no way detracts from the efficient 1 Double contact filament control jack. thrown slightly out of resonance. For con- working of the amplifier, as the layout is 1 Double contact jack. trolling the oscillations inherently present such that leads have been kept very short. 1 Grid leak (value varying with tube in a circuit where both grid and plate cir- Ruggedness and efficiency, have been the used; usually 2 megohms for a Radio- cuits are tuned, the potentiometer is used. keynotes in this construction and design. tron tube). An additional binding post is provided for The general appearance can be judged from 11 Binding posts. the last stage so that it may' be possible to the accompanying photographs. 4 feet 4 -inch angle brass. put higher voltages on the plate of the last Below is listed such apparatus as was 1 Strip of bakelite, by % by 8 inches. tube. used in the construction of this outfit. No 4 Lengths of bus bar wire. The by-pass condenser around the pri- specific makes of apparatus can be recom- 1 Bakelite tube, 2/ inches diameter by mary of the first stage transformer should mended for purely ethical reasons, but it 1/ inches long. be of such a value as to offer radio fre- cannot be too strongly recommended that Miscellaneous brass stock. quency currents a very low impedance path only the best of materials be used in the Before starting with our actual construc- but to offer a high impedance to audio fre- assembly. Cheap material may please the tion, let us examine the circuit we are going quency currents, forcing them to go through eye, but invariably such apparatus ceases to to use, as illustrated in Fig. 1. It will be the winding of the transformer. If the give good service in a remarkably short seen that only two jacks are used, one in the. value of the condenser is too large, audio 1084 Science and Invention for March, 1923 1085

G.V. -G,rid Variometér, VC.- Vario Coupler PV.- Plate Variometer or Tickler Coil.

I Storage battery..

II

I I

1¡ Ì 0-Lr-:,

; ._ . 'B' batteries

45V. 90V.

tuner is shown in Fig. 1. A complete circuit diagram showing the connections of the amplifier in conjunction with a short wave regenerative tube be passed in addi- these two extremes. Around the potentio- order of .00025 mfd. A hard amplifier frequency currents will should be tion to the radio frequency currents: if too meter, a .0005 mfd. condenser is quite suit- (U. V. 201 or similar types) radio frequency current able, as no audio frequency currents are used in the first socket, a detector tube in small, not enough in the last can pass. It has been found that a value of present in this circuit. The coupling con- the second, and amplifier tubes on page 1130) .001 mfd. is a happy compromise between denser to the detector tube should be of the (Continued 4 Holes. Drill and countersink /' ,for No. 8-32 flat head machine screws. 12 Holes. 3/16 Drill and countersink\\\

16 t-1 ` 5" ® 8 y .4-" ss, , \, . 5 Holes A/ ' ig drill and /j 42 Drill for// tond ¡_Drill countersink. enser shaft. 4 holes for Section thru A -A _- rheostnt shaft %%r FIG.2 %/ 23 23'---I i/ mIe Drill 2 holes for jacks., 1t ' ;J ' ,, 10,/ L- ma i % d , 4' 6 / Drill 3 ho es to clear Nº.t3 32 screws.

'8 7 10" Drill hole for Drill 6 holes for binding posts. Cut out right angled piece along potentiometer shaft. dotted lines where bend is to FIG.3 be made. sheet of heavy paper 7 by 10 inches. Complete panel layout for the amplifier is shown in Fig. 3. It is advisable to lay out the location of all holes on a panel and the holes drilled through both. When the panel has been completely drilled this template can be Tills template can then be pasted on the to the various instruments. scraped off and a grain finish put on the panel. Fig. 2 shows the dimensions of the brass brackets used support ä r, in th $1100. 0 Km uo terference Preventer Contest FIRST PRIZE ,,,,,,,,,,1111111111111111111111,111111,111,11111111111111111,111m11,111111111,,,1,,,11,,,,,.. FOURTH PRIZE By J. Brydson PRIZE WINNERS By C. Kenard Eser THE only apparatus necessary for this FIRST PRIZE The selective tuner described by the very selective tuner is two vario - $50.00 in gold, Mr. J. Brydson, P. 0. Box writer, makes use of an auxiliary induc- couplers, a variometer, and a .001 314, Austin, Texas. tance and capacity connected from the aerial M.F. variable condenser. These are SECOND PRIZE lead-in to the plate of the $20.00 detector tube. This connected up as shown in the accom- in gold, Mr. Caesar De Carlo, 898 provides a shunt through the phones to the panying diagram, Gravesend Ave., Brooklyn, N. Y. the two leads marked "To THIRD ground, and when the auxiliary circuit is PRIZE tuned to $15.00 in gold, Mr. E. J. Fancher, Gilboa, the undesired signal, it shunts N. Y.

VARIO -COUPLER FOURTH PRIZE VARIABLE LAND $10.00 in gold, Mr. C. Kenard Eser, 33 N. Linwood Ave., Baltimore, Md. tl FIFTH PRIZE il I $5.00 in gold, J. E. I' I Martin, 75 Allen Road, , Beckenham, Kent, England. TO DET ECTOR for wave lengths of 450 to 700 meters. Two different circuits may be used with this an- paratus, one being in series with the an- tenna and the other across the primary of the vario -coupler. The former is shown in solid lines, and the latter in dotted lines in the diagram given herewith. The writer has always found it advisable to connect the rotating plates of the con- VAR 10M ET E R TO GROUND VARIO -COUPLER denser to the aerial lead-in. If the wave - rIG.I trap does not work the first time, reverse the coil connections across the condenser, but The first prize winning circuit shown above, do not change The fourth prize was awarded to the "by- is of the "wave filter" type. the condenser leads. pass" circuit shown in Fig. 4. that signal directly Detector" being connected either to the ground, the radio to a crys- frequency current not affecting the tal detector and fixed condenser or a regular receivers. The tapped inductance coil is made ap- audion detector unit. Sharp tuning is ac- proximately complished in two the same as the primary of the ways with this circuit, vario-coupler, and the connections one by means of the filter action of the two are made vario -couplers, as shown: a .001 M.F. condenser being used and the other by the close in series with the regulation of inductance in the primary antenna, and another one cir- of the same capacity in series with the aux- cuit of the first coupler, which is given by iliary the variometer. inductance. After the coupling is once adjusted, the FIFTH PRIZE 360 and 400 meter stations may be separated by manipulation of the variometer By J. E. Martin and the The inductance variable condenser, with practically no varia- A consists of 80 turns of tion of the coupling in either vario -coupler. Litz wire, wound on a tube 3% inches in diameter, and tapped every tenth turn. The condenser VARIO" COUPLER in shunt with this coil has a SECOND PRIZE capacity of .0015 M.F. SPECIAL TUNER - The inductance marked B consists of a By Caesar De Carlo tube 3% inches in TO GROUND B. BAT diameter, wound with FIG 3 64 turns of Litz and tapped every 3-1/3 The apparatus described below and il- TO STORAGE BAT turns. The lustrated herewith, has condenser used in connection given excellent re- with this coil has a sults when used by the writer in A specially constructed tuner is used in the capacity of .0005 M.F. connection third prize circuit to obtain selectivity, and The writer found it advantageous with a standard short wave regenerative set in tun- is shown in Fig. 3. ing to control both circuits at the same time, containing a vario -coupler and two vario - one with meters. It is of the each hand, with the filament of the wave -trap type and con- tube burning fairly brightly. sists of a .001 M.F. variable condenser, and THIRD PRIZE The tuning is a D.L.-75 continued very slowly until the carrier wave or D.L.-100 honeycomb cell. By E. J. Faucher is heard, whereupon The 75 turn coil is used on wave lengths the filament is turned from down to normal brilliancy, and the set tuned 250 to 450 meters, and the larger one H .0005 variable condenser is used in con- more carefully. nection with a coil wound on the same sized TO AERIAL VARIOMETERS tube and NONEYCOM BCOIL with the same number of turns as the primary of the vario -coupler. This coil is placed on end, and a variometer connected in series with the plate laid on its side on top of it, so as to provide an inductive coup- ling between the two. If no plate vario - meter is used, the coil may be wound on one end of a longer tube, on the other end of which is wound 50 turns of No. 24 D.C.C. wire, tapped at about the 30th, 35th, 40th. 45th and 50th turns. There should be a space of about r/z inch between the two windings. In this case, a variable condenser with a capacity of .0005 should be shunted across the plate coil, as no provision is made for varying the inductance as in the case of a variometer. The latter connection is in- VARO -COUPLER dicated in dotted lines in the accompanying B. BAT diagram. TO GROUND F -I G. 2 TO STORAGE BAT. With this circuit, the writer could tune out a broadcasting station in Schenectady The so-called "phantom" circuit was awarded The "wave trap" which fifth prize, and is shown circuit, which won second is very close to his home, and re- The above in Fig. 5. prize, is shown in Fig. 2. ceive from points data on the inductances used are given as far distant as Chicago. in the text. 1086 NEWARK

f lli . í%) vin RADIO aniVö lIi - NOUJE - urA TELEPNONE FAR ROCKAW AY TELEPHONE EXCHANGE

DOCTOR - 05' 5mv :._. 5 foorr Ró dIl° in" on one WHEN the radio returns of the at his home in Far Rockaway, when the Instead of continuing to "listen bell rang. It appears that Dr. loud speaker horn, a second was connected World Series baseball games were telephone in the at least one Richard H. Hoffman, a well known New in series. Then the gardener brought being broadcasted, hose, which saved the day. One end unique turn was given this event, recent in- York physician and one of the director's lawn known, friends, had also been "listening in" to the of the hose was stuffed down the throat formation indicates. As is generally and the other fastened the voice of the broadcaster was transmitted radio returns at his own home. His storage of the loud speaker, to battery ran down. to the mouth -piece of the land -telephone. from the Polo Grounds, New York City, doc- the wireless he hurried to 'phone his friend "Central" set the connection to the good Newark, New Jersey, where In haste, Dr. Hoffman, lis- broadcasting was done. to inquire what to do. The radio corporation tor's home telephone, and the receiver of his land -telephone, New York radio director offered to assist him, and this is tening to One of the directors of a was able to hear every play. company was giving a "radio baseball party' how it was done.

I I I I I I I I I I III IIIIII II I I I II I IIi11111111111111111I111111111111111111111111111111111111 I I I I I IIIIII I I I I I II IIII I I I I I IIII I III II I II II II III IIIII I I I I I I I I I II I II !I I I I iII III II I I III I I I I I I I I I I I I I I I I I I I I I I I IIIIII IIIIIIII I I I I I I I I I I II III II II IIIII II I I I I I I I I I I I II III I III III II I I I I I I I I I I II II III III IIIIIIII II III I I I I I I I II I II I I I I I I I I IIIIIIIIIIIIIIIII I I I I I I I I I IIII II I1111111111IIIII IIIII I I I I I I I I I I I I I I I I I I I I II JI I II IIIIII I I11111111111111I I I I II II II IIIIII $100.00 Prñze as : Ilndnflg Pot' Contest con- JIYII1MmilFIDIIIlmulnIllllllIlIl llllllllllllIll III tÌHI11IIIIII 1111Ii1111niI111111011ullullillllllillllli119 The other day we saw a new spring E announce herewith a new the advantage of open to everyone except FIVE PRIZES IN "SIMPLEST binding post possessing test flat, so that no matter how hard one manufacturers. of such devices, POST" CONTEST being this BINDING might push on it, it would not pinch or whether they are readers of has a double magazine or not, and for which injure. This binding post First Prize. . $50.00 in gold set of hook -like jaws, and the wire is we offer $100.00 in gold in five prizes for passed through it ; as soon as the pressure most efficient binding " . . 20.00 " " the simplest and Second the wire is gripped tightly and post designs. Strange as it may seem, cc is released improve- Third " .. 15.00 " cannot jar loose. A simple home-made there is still a lot of room for cc also shown in the realm of binding posts. Some 10.00 " spring binding post is = ment in the Fourth " .. picture which the editor once constructed - of the commercial products in simple . and four staples. Some are shown in the accom- Fifth " 5.00 " " from a safety pin binding posts time ago there appeared on the automobile panying illustration. a battery connector the accompanying illustra- Total, $100.00 accessory market As shown in fitted with spiral spring terminals, which E. forms of spring elnu,,,,l,,,,,,,,,,,,11111,,,,,,,,IlIIn,,,,m11111.1,1m.11111il,,,,l, II tion, there are several to be forced over the bind- binding posts, millions of which have been were intended profit to the maker. ing post, so as to grip it tightly. s. - sold at a goodly There is a reasonable possibility that, - However, with this class of binding posts, hurt de- if some of these binding posts prove as P. in general, the fingers are often it be possible member, so as to good as we anticipate, will = pressing the spring for the editors to make arrangements for engage the wire. the designers to get in touch with several A novel type of binding post patented a companies, who are interested in obtaining by H. Gernsback is that incorporating type to manufacture member, which slides new devices of this spring -actuated top for the commercial market. down within the post, producing an align- allowing the wire A short description of about 100 words = ment of the apertures, or so, will be amply sufficient together to be passed through the holes in both of members. When with a clear drawing or else a model stationary and moving the binding post. Make drawings in ink pressure is released on the top member, and the wire and typewrite descriptions if possible, on E the spring forces it upward separate sheets. This contest closes at is tightly gripped. Another binding post favor, noon, May 10th. Should two contestants which has met with considerable the same prize will shell-like member submit the same idea, is that in which the top be paid to both. Address all communica- screws downward and clamps the wires in Binding Post in the illus- tions to Editor, Simplest the slot. This is also shown Contest, in care of this publication. tration. Various styles of spring binding posts.

MI- 1087 RADIO BROADCAST

te ist of Broa Cß5e 5üzeIlons UnUe(.1 5üates REVISED AND CORRECTED TO JANUARY 2, 1923

All stations operate on 360 meters except as Call below. Name City and State Call Name City and State KFBV Clarence O. Ford, Those with * on 400; t on 485; o in back of MOB New Mexico College of Agriculture any sign indicates "only," Colorado Springs, Colo. and Mechanic Arts, thus to means 485 tKFC Northern Radio & meters only. Electric Co., State College, N. Mex. Seattle, Wash. ROG Western Radio Electric Co., Call Name City and State KFCB Nielsen Radio Supply Co., Phoeniz, Los Angeles, Cal. KDKA Westinghouse Elec. & Mfg. Ariz. KON Holzwasser, Inc San Diego, Cal. Co., KFCC Auto Supply Co Wallace, Idaho KOP Detroit East Pittsburgh, Pa. KFCD Salem Electric Police Dept....Detroit, Mich. tKDN Leo. J. Meyberg Co., Co Salem, Ore. KPO Hale Bros San Francisco, Cal. KFCF Frank A. Moore..Walla Walla, Wash. KQI University San Cal. KFCH Electric Service of California. Berkeley, Cal. KDPM Westinghouse Sr Station, Inc., KQP Hood River News (Radio Elec. Mfg. Co., Billings, Mont. Shop of Cleveland, Ohio KFCK Colorado Hood River) Hood River, Ore. KDPT Southern Electrical Springs Radio Co., KQV Doubleday Hill Elec. Co., Co., Colorado Springs, San Diego, Cal. Colo. Pittsburgh, Pa. tKDYL Telegram toKFCL Los Angeles Union Stock Yards, KQW Chas. D. Herrold Publishing Co., Los Angeles, San José, Cal. Salt Lake City, Utah Cal. KQY Stubbs Electric Co Portland. Ore. KDYM KFCM Richmond Radio Shop. Richmond, Cal. KRE Maxwell Electric Savoy Theatre San Diego, Cal. KFCQ Motor Service Station, Co Berkeley, Cal. KDYO Carlson & Simpson toKSD Post Dispatch St. Louis, San Diego, Cal. (Norman R. Hood)... Casper, Wyo. Mo. tKDYQ Oregon Inst. of Technology, KFDA KSL The Emporium.... San Francisco, Cal. Adler's Music Store Baker, Ore. KSS Prest & Dean Radio Co., Portland, Ore. K FDB John D. McKee.. San Francisco, Cal. KDYS Great Falls Tribune, KFDC Long Beach, Cal. Radio Supply Co. (E. B. Craney), KTW First Presbyterian Church, Falls, Mont. Spokane, KDYV Cope & Cornwell Co.reat Wash. Seattle, Wash. KFDD St. Michaels Cathedral...Boise, Idaho tKUO San Francisco Salt Lake City, Utah KFDF Wyoming Radio Examiner, KDYW Radio Dept. Smith Hughes Corp..Casper, Wyo. San Francisco, Cal. KFDH University of Arizona..Tucson, Ariz. KUS City Dye Works Machinery Co Phoenix, Ariz. KFDJ Oregon Agricultural & Laundry Co., KDYX Honolulu Star Bulletin, College, Los Angeles, Cal. Corvallis, Ore. Honolulu, T. H. KFDL KUY Coast Radio Co., Inc.. El Monte, Cal. KDYY Rocky Mountain Knight -Campbell Music Co., KVQ Sacramento Bee (Jos. McClatchy Radio Corp., Denver. Colo. Denver, Colo. K FEB City of Taft Co.) Sacramento, Cal. KDZA Arizona Daily Tucson, Taft, Cal. KWG Portable Wireless Telephone Co., Star Ariz. KFEC Meier & Frank Co....Portland, Ore. KDZB Frank E. Siefert Bakersfield, Cal. Stockton, Cal. KDZE The KFED Billings Polytechnic Inst., tKWH Los Angeles Examiner, Rhodes Co Seattle, Wash. Polytechnic, Mont. KDZF Automobile Club of Southern KFEJJ Guy Greason Los Angeles, Cal. California Tacoma, Wash. KXD Herald Publishing Co..Modesto, Cal. Los Angeles, Cal. EFE Radio Equipment Co Denver, Colo. KDZG Cyrus Pierce & Co.San Francisco, Cal. KXS Braun Corp Los Angeles, Cal. iKDZH Fresno KFFA Dr. R. O. Shelton... San Diego, Cal. KYI Bakersfield Evening Herald.. Fresno, Cal. KFFE Eastern Oregon Radio Co.. Californian, KDZI Electric Supply Co. Wenatchee, Wash. Bakersfield, Cal. KDZK Nevada Machinery Pendleton, Ore. tKYJ L eo J. Meyberg Co Los Angeles, & Elec. Co., KFGG Astoria Budget Astoria, Ore. K.YQ Cal. Reno, Nev. KFGH Electric Shop Honolulu. Hawaii KDZL Rocky Mountain Stanford University, toKYW Radio Corp., Stanford University, Cal. Westinghouse Elec & Mfg. Co.. Ogden, Utah KFHJ Fallon Co Santa Barbara, Cal. Chicago, Ill. KDZM E. A. Hollingsworth.Centralia, Wash. K FI Earle KYY Radio Telephone Shop, KDZP Newbery Electric C. Anthony, Inc., Corp., Los Angeles, Cal. San Francisco, Cal. Los Angeles, Cal. KFV Foster KZC Public Market & Dept. Stores Co., KDZQ Wm. D. Pyle -Bradbury Radio Store, Motor Generator Co., Yakima, Wash. Seattle, Wash. Denver, Colo. tKZM Preston D. Allen KDZR Bellingham KFZ The Doerr Mitchell Elec. Co., Oakland, Cal. Publishing Co., Spokane, Wash. tKZN The Deseret News, Bellingham, Wash. KGB Wm. KDZT Seattle Radio Association, A. Mullins Electric Co., Salt Lake City, Utah Tacoma, Wash. KZV Wenatchee Battery & Motor Co., Seattle, Wash. KGG Hallock & Watson KDZW Claude W. Gerdes.San Francisco, Radio Service, Wenatchee, Wash. Cal. Portland, Ore. KZY Atlantic & Pacific Radio Supply Co., KDZX Glad Tidings Tabernacle, KGN Northwest Radio Mfg. San Francisco, Co., San Francisco, Cal. Cal. Portland. Ore. WAAC Tulane University...New Orleans, La. KDZZ Kinney Bros. & Sipprell, EGO Altadena Radio Laboratory, WAAD Everett, Ohio Mechanics Institute, Wash. Pasadena, Cal. Cincinnati. Ohio KFAC Glendale Daily Press... Glendale, Cal. KGU Marion A. Mulroney, KFAD McArthur Bros. Mercantile tWAAF Chicago Daily Drover's Journal, Co., Honolulu, Hawaii Chicago, Ill. Phoenix, Ariz. nKGW Portland Morning WAAH KFAE State College of Washington, Oregonian, Radio Dept. Commonwealth Elec- Portland, Ore. tric Co St. Paul, Minn. Pullman, Wash. KGY St. Martins KFAF Western Radio College....Lacey, Wash. WAAJ Eastern Radio Institute. Boston, Mass. Corp. .Denver, Colo. tKDH C. F. Aldrich Marble & Granite Co., KFAJ University of Colorado.Boulder, Colo. tWAAK Gimbel Bros Milwaukee, Wis. KFAN The Electric Colorado Springs, Colo. Shop.... Moscow, Idaho toKHJQ Times Mirror Co..Los Angeles. Cal. WAAL Anderson Beamish Elec. Co., KFAP Standard Publishing Co..Butte, Mont. KHKJCQ Louis Minneapolis, Minn. KFAQ City Wasmer Seattle, Wash. of San losé San José, Cal. Standard Radio Co..Los Angeles, Cal. WAAM I. R. Nelson Co Newark, N. T. KFAR Studio Lighting Service Co., The Radio Shop tWAAN University of Missouri Columbia, Mo. Hollywood, Sunnyvale, Cal. tWAAP United Electric KFAS Cal. C. O. Gould Stockton, Cal. Co... Wichita, Kans. Reno Motor Supply Co..Reno, Nev. KJR Vincent I. Kraft (operated by North. WAAQ New England Motor Sales Co., KFAT S. T. Donohue Eugene, Ore. west Radio Service).Seattle, Wash. Greenwich, Conn. tKFAU High School Boise, Idaho KJS Bible Institute of Los Angeles. WAAS Georgia Radio Co Decatur, Ga. KFAV Abbot Kinney Co Venice, Cal. tWAAW Omaha Grain Exchange Omaha, Nebr. KFAW Register -Radio -Den Los Angeles, Cal. -Radiophone, KLB J. J. Dunn & Co Pasadena, Cal. WAAX Radio Service Corp Crafton, Pa. Santa Ana, Cal. KLN Monterey Electric Shop, WAAY Yahrling-Rayner Music Co., tKFAY Virgin Radio Service.. Medford, Ore. Del KFAZ C. H. Weatherill Monte, Cal. Youngstown, Ohio Reedley, Cal. KLP Colin B. Kennedy Corp. WAAZ Hollister -Miller Motor Co., KFBB F. A. Buttrey & Co... Havre, Mont. Los Altos, Cal. Emporia, Kansas KFBC Normal Heights Station KLS Warner Bros (W. K. Oakland, Cal. tWAH Midland Refining Co., Azbill) .... San Diego, Cal. KLX Oakland Tribune Oakland, Cal. El Dorado, Kansas KFBD Mercantile Trust Co....Hanford, Cal. Reynolds Radio WBAA KFBE R. H. tKLZ Co Denver, Colo. Purdue University, Horn (Cline's Electric KMC W. W. Lindsay, Jr Reedley, Cal. West Lafayette, Shop) San Luis Obispo, Cal. Ind. KFBG tKMJ San Joaquin Light & Power Corp., WBAB Andrew J. Potter.... Syracuse, N. Y. First Presbyterian Church, Fresno, Cal. WBAD Sterling Electric Co., Tacoma, Wash. KMO Love Electric Co Tacoma, KFBH Thomas Musical Wash. Minneapolis, Minn. Co.Marshfield, Ore. ENI T. W. Smith Eureka, Cal. WBAF Fred M. Middleton. Moorestown, N. J. tKFBK Kimball -Upson Co...Sacramento, Cal. Roswell tENJ Public Service Co., tWBAG Diamond State Fibre Co.. KFBL Leese Bros Everett, Wash. Roswell, N. Mex. KFBM Cook & Foster & Astoria Bridgeport, Pa. KNN Bullock's Los Angeles, Cal. WBAH The Dayton Co...Minneapolis, Hardware Co Astoria, Ore. KNT Grays Harbor Radio Co. (Walter Minn. KFBN Borch Radio Corp. (Portable),...Cal. Hemrich) WBAJ The Marshall Gerken Co.Toledo, Ohio KFBO Savage Electric .... Aberdeen, Wash. Co....Prescott, Ariz. KNV Radio Supply Co.. Los Angeles, Cal. WBAN Wireless Phone Corp.Paterson, N. j. KFBS Trinidad Gas & Electric Co. and KNX Electric Lighting Supply Co.. Chronicle News Trinidad. WBAO James Millikin University, Colo. Los Angeles, Cal. Decatur, KFBU The Cathedral (Bishop Thomas), toEOA Young Mens Christian Assoc., toWBAP Ill. Laramie, Wyo. Wortham-Carter Pub. Co., Denver. Colo. Fort Worth, Texas 1088 Call Name City and State Call Name Cily and State Call Name City and State WBAU Republican Publishing Co., \VEAS Hecht Co Washington, D. C. *toWHB Sweeney School Co.Kansas City, Mo. Hamilton, Ohio WEAT John J. Fogarty Tampa. Fla. WHD West Virginia University, tWBAV Erner & Hopkins Columbus, Ohio WEAU Davidson Bros. Co. Sioux City, Iowa Morgantown, W. Va. WBAW Marietta College Marietta. Ohio WEAV Sheridan Electric Service Co., WHK Radiovox Co. (Warren R. Cox). WBAX John H. Stenger, Jr., Rushville, Nebr. Cleveland, Ohio Wilkes-Barre, Pa. WEAW Arrow Radio Laboratories, WHN Ridgewood Timer; Publishing Co., *oWBAY American Tel. & Tel. Co., Anderson, Ind. Ridgewood, N. Y. New York, N. Y. tWEAX T. J. M. Daly Little Rock, Ark. t W HU Wm. B. Duck Co Toledo, Ohio WBL T & H Radio Co...Anthony, Kansas WEAY Will Horwitz, Jr Houston, Tex. toWHW Stuart W. Seeley.East Lansing, Mich. WBS D. W. May, Inc Newark, N. J. WEB Benwood Co St. Louis, Mo. \VIAB Joslyn Automobile Co.. Rockford, Ill. tWBT Southern Radio Corp.Charlotte, N. C. tWEH Midland Refining Co Tulsa, Okla. t WIAC Galveston Tribune...Galveston, Texas WBU City of Chicago Chicago, Ill. tWEV Huriburt-Still Electrical Co., \CLAD Ocean City Yacht Club, *o\VBZ Westinghouse Elec. & Mfg. Co., Houston, Tex. Ocean City, N. J. Springfield, Mass. tWEW St. Louis University ...St. Louis, Mo. \\IAE Mrs. Robert E. Zimmerman, WCAB Newburgh Daily News, tWEY Cosradio Co Wichita, Kansas Vinton, Iowa Newburgh, N. Y. *toWFAA Dallas News -Dallas Journal, \VIAF Gustav A. De Cortin.New Orleans, La. WCAC John Fink Jewelry Co., Dallas, Tex. WIAH Continental Radio & Mfg. Co., Fort Smith, Ark. WFAB Carl F. Woese Syracuse. N. Y. Newton, Iowa WCAD St. Lawrence University. Canton, Ohio WFAC Superior Radio Co....Superior, Wis. WIAI Heer Stores Co Springfield, Mo. *oWCAE Kaufman & Baer Co...Pittsburgh, Pa. WFAD Watson Weldon Co....Salina, Kansas WIAJ Fox River Valley Radio Co., WCAG Daily States Pub. Co., WFAF H. C. Spratley Radio Co., Neenah, Wisc. New Orleans, I.a. Poughkeepsie, N. Y. tWIAK Daily Journal -Stockman. Omaha, Neb. WCAH Entrekin Electric Co.Columbus, Ohio \VFAG The Radio Engineering Laboratory, WIAO School of Engineering & Wisconsin tWCAJ Nebraska Wesleyan University, Waterford, N. Y. News. Milwaukee, Wis. University Place, Nebr. \V FAH Electric Supply Co. Port Arthur, Texas WIAQ Chronicle Publishing Co, WCAK Alfred P. Daniel Houston, Texas \VFAJ Hi -Grade Wireless Instrument Co., Marion, Ind. WCAL St. Olaf College.... Northfield, Minn. Ashville, N. C. WIAR Paducah Evening Sun...Paducah, Ky. WCAM Villanova College Villanova, Pa. \VFAM Times Publishing Co.St. Cloud, Minn. WIAS Burlington Hawkeye & Home WCAO Sanders and Stayman Co.. tWFAN Hutchinson Electric Service Co., Electric Co Burlington, Iowa Baltimore, Md. Hutchinson, Minn. WIAT Leon T. Noel Tarkio, Mo. tWCAP Central Radio Service...Decatur, Ill. WFAQ Missouri Wesleyan College & WIAU American Trust & savings Bank, WCAQ Tri-State Radio Mfg. & Supply Co., Cameron Radio Co...Cameron, Mo. Le Mars, Iowa Defiance, Ohio WFAS United Radio Corp.Fort Wayne, Ind. \VIAV New York Radio Laboratories, WCAR Alamo Radio Elec. Co., tWFAT Daily Argus Leader, Binghamton, N. Y. San Antonio, Texas Sioux Falls, So. Dak. WIAW Saginaw Radio & Electric Co., WCAS Wm. Hood Dunwoody Industrial WFAU Edwin C. Lewis Boston, Mass. Saginaw, Mich. Institute Minneapolis, Minn. tWFAV University of Nebraska Lincoln,Nebr. \VIAX Capitol Radio Co Lincoln, Nebr. toWCAT S. Dakota School of Mines, WFAW Miami Daily Metropolis-Miami, Fla. \VIAY Woodward & Lothrop, Rapid City, S. Dak. WFAY Daniels Radio Supply Co., Washington, D. C. tWCAU Philadelphia Radiophone Co., Independence, Kansas WIAZ Electric Supply Sales Co., Philadelphia, Pa. tWFAZ South Carolina Radio Shop, Miami, Fla. WCAV J. C. Dice Electric Co., Charleston, So. Car. WIK K & L Electric Co...McKeesport, Pa. Little Rock, Ark. *foWBI Strawbridge & Clothier, \VIL Continental Electrical Supply Co., tWCAW Quincy Electric Supply Co.. Philadelphia, Pa. Washington, D. C. Quincy, Ill. WGAB QRV Radio Co Houston, Tex. t\VIP Gimbel Bros Philadelphia, Pa. WCAX University of Vermont, WGA D Spanish American School of Radio- tWIZ Cino Radio Mfg. Co.Cincinnati, Ohio Burlington, Vt. telegraphy Ensenada, P. R. WJAB American Radio Co....Lincoln, Nebr. WCAY Kesselman O'Driscoll Co., WGAH New Haven Electric Co.. WJAC Redell Co Joplin, Mo. Milwaukee, Wis. New Haven, Conn. WJAD Jackson's Radio Engineering WCAZ Robt. E. Compton and Carthage WGAJ W. H. Gass Shenandoah, Iowa Laboratories Waco, Texas College Carthage, Ill. WGAK Macon Electric Co Macon, Ga. tWJAE Texas Radio Syndicate, WCE Findley Electric Co.. WGAL Lancaster Elec. Supply & Con- San Antonio, Texas Minneapolis, Minn. struction Co Lancaster, Pa. WJAF Muncie Press -Smith Electric, WCK Stix Baer & Fuller Co.St. Louis,.Mo. \VGAM Orangeburg Radio Equipment Co., Muncie, Ind. *WCM University of Texas Austin, Texas Orangeburg, So. Car. WJAG Norfolk Daily News.... Norfolk, Nebr. t WCN Clark University ....Worcester, Mass. WGAN Cecil E. Lloyd Pensacola, Fla. WIAJ Y. M. C. A Dayton, Ohio * t o\VCX The Detroit Free Press. WGAQ Glenwood Radio Corp , t\VJAK White Radio Laboratory, Detroit, Mich. Shreveport, La. Stockdale, Ohio toWDAC Illinois Watch Co .... Springfield, Ill. tWGAR Southwest American.Fort Smith, Ark. WJAL Victor Radio Corp Portland, Me. tWDAE Tampa Daily Times Tampa. Fla. WGAS The Ray -Di -Co. Organization, \V JA M D. M. Perham.... Cedar Rapids. Iowa *to \VDAF Kansas City Star....Kansas City, Mo. Chicago, Ill. \VJAN Peoria Star -Peoria Radio Sales Co., \VDAG J. Laurance Martin..Amarillo, Texas WGAT American Legion, Dept. of Nebraska, Peoria, Ill. tWDAH Mine & Smelter Supply Co., Lincoln, Nebr. WJAP Kelley -Duluth Co Duluth, Minn. El Paso, Texas WGAU Marcus G. Limb Wooster, Ohio WJAQ Capper Publications Topeka, Kan. tWDAI Hughes Electrical Corp., WGAW Ernest C. Albright Altoona, Pa. \VJAR Outlet Co. (J. Samuels & Bro.), Syracuse, N. Y. WGAX Radio Electric Co, Providence, R. I. t\VDAJ Atlanta & West Point R. R. Co., Washington Court House, Ohio WJAS Pittsburgh Radio Supply Co., College Park, Ga. WGAY Northwestern Radio Co., Pittsburgh, Pa. WDAK The Hartford Courant, Madison, Wis. \VJ.\T Kelley-Vawter Jewelry Co., Hartford, Conn. WGAZ South Bend Tribune. South Bend, Ind. Marshall, Mo. tWD.\I. Florida Times -Union. Jacksonville, Fla. tWGF The Register & Tribune, WJ,\U Yankton College...Yankton, So. Dak. \VI)AO Automotive Elec. Co...Dallas, Texas Des Moines, Iowa WJAX Union Trust Co Cleveland. Ohio WDAP Midwest Radio Central, Inc., t\\ GI American Radio & Research Corp., WJAZ Chicago Radio Laboratory, Chicago, Ill. Medford Hillside, Mass. Chicago, Ill. WDAQ Hartman Riker Elec. & Machine Co., \VGL Thos. F. J. Howlett..Philadelphia, Pa. \VJD Richard H. Howe Granville, Ohio Brownsville, Pa. *oWGM Atlanta Constitution Atlanta, Ga. \VJIi White & Boyer Co..Washington, D. C. WDAR Lit Bros Philadelphia, Pa. tWGR Federal Telephone & Telegraph Co., \VJK Service Radio Equipment Co., WDAS Samuel A. Waite Worcester, Mass. Buffalo, N. Y. Toledo, Ohio WDAU Slocum & Kilburn. tWGV Interstate Electric Co., WJX De Forest Radio Telephone & New Bedford, Mass. New Orleans, La. Telegraph Co....New York, N. Y. \VDAV Muskogee Daily Phoenix, *toWGY General Electric Co., \VJZ Westinghouse Elec. & Muskogee, Okla. Schenectady, N. Y. Mfg. Co.,Ne N. J. WDAX First National Bank. Centerville, Iowa tWHA University of Wisconsin, iWKAA H. F. Paar (Republican Times). Madison, Wis. Cedar Rapids, Iowa tWDAY Fargo Radio Service Co., \VHAA of Iowa, Fargo, N. Dak. State University WKAC Star Publishing Co Lincoln, Nebr. Iowa City, Iowa WKAD Charles Looff (Crescent Park), WDM Church of the Covenant, Clark W. Thompson (Fellman's Washington D. C. t\VHAB East Providence, R. I. Dry Goods Co.) \VKAF W. S. Radio Supply Co., WDT Ship Owners Radio Service, Galveston, Tex. Wichita Falls, Texas New York, N. Y. WHAC Cole Bros., Electric Co., WK AG Edwin T. Bruce, M.D., \VDV John O. Yeiser, Jr....Omaha, Nebr. Waterloo, Iowa Louisville, Ky. WDY Radio Corp. of America. tWHAD Marquette University, \VKAH Planet Radio Co. Roselle Park, N. J. Milwaukee, Wis. West Palm Beach, Fla. WDZ J. L. Bush Tuscola, Ill. WHAE Automotive Electric Service Co., WKAK Okfuskee County News, Sioux City. Iowa Okemah, Okla. WEAA Fallian & Lathrop Flint, Mich. WHAF Radio Electric Co....Pittsburgh, Pa. WK AL Gray & Gray Orange, Texas tWEAB Standard Radio Equipment Co., WHAG University of Cincinnati, WK AN Alabama Radio Mfg. Co., Fort Dodge, Iowa Cincinnati, Ohio Montgomery, Ala. tWEAC Baines Electric Service Co., WHAH Hafer Supply Co Joplin, Mo. WK AP Dutee W. Flint Cranston, R. I. Terre Haute, Incl. WHAI Radio Equipment & Mfg Co., \VK.\Q Radio Corp. of Porto Rico.. WEAD Northwest Kansas Radio Supply Co., Davenport, Iowa San Juan, P. R. Atwood, Kansas WHAK Roberts Hdwe. Co.. WKAR Michigan Agricultural College, WEAR Virginia Polytechnic Inst., Clarksburg, W. Va. East Lansing, Mich. Blacksburg, Va. WHAL Iansing Capital News.Lansing, Mich. *oWEAF Western Electric Co.New York, N. Y. *WHAM University of Rochester, WKAS L. E. Lines Music Co.. WEAG Nichols-Hineline-Bassett' Laboratory, Rochester, N. Y. Springfield, Mo. Edgewood, R. I. WHAO Frederic A. 'Hill Savannah, Ga. WKAV Laconia Radio Club...Laconia, N. H. Wis. tWEAH Wichita Board of Trade & Lander \VHAP Otta and Kuhns Decatur. Ill. WKAW Turner Cycle Co Beloit, Radio Co Wichita, Kansas WHAQ Semmes Motor Co.Washington, D. C. WKAX William A. MacFarland, Bridgeport, Conn. WEAI Cornell University Ithaca, N. Y. WHAR Paramount Radio & Elec. Co.. WEAJ University of So. Dakota. Atlantic City, N. J. WKAY Brenau College Gainesville, Ga. Vermillon, S. Dak. tWHAS Courier -Journal and Louisville Times, WKAZ Landau's Music & Jewelry Co., \VEAK Julius B. Abercrombie. St. Joseph, Mo. Louisville, Ky. Wilkes-Barre, Pa. WEAM Borough of No. Plainfield, WHAV Wilmington Electrical Specialty Co., WKC Joseph M. Zamoiski Co., North Plainfield, N. J. Inc. Wilmington, Del. Baltimore, Md. tWEAN Shepard Co Providence, R. I. Pierce Electric Co Tampa, Fla. tWKN Riechman Crosby Co.Memphis, Tenn. tWEAO Ohio State University, WHAW WHAT The Huntington Press, tWKY WRY Radio Shop, Columbus, Ohio City, Okla. tWEAP% Mobile Radio Co Mobile, Ala. Huntington, Ind. Oklahoma WEAR Baltimore American & News *oWHAZ Rensselaer Polytechnic Inst., WLAC North Carolina State College. Publishing Co. Baltimore, Md. Troy, N. Y. Raleigh, N. C. 1089 Call Name City and. State Call Name City and State Call Name City and State WLAF Johnson Radio Co Lincoln, Nebr. WNAN Syracuse Radio Telephone Co., fWPAK North Dakota Agricultural College, "toWLAG Cutting & Washington Radio Corp., Syracuse, N. Y. Agricultural College., N. D. Minneapolis, Minn. WNAP Wittenberg College..Springfield, Ohio WPAL Superior Radio & Tel. Equipment Co., WLAH Samuel Wordworth...Syracuse, N. Y. WNAQ Charleston Radio Electric Co., Waco Columbus, Ohio tWLAJ Electrical Supply Co., Charleston, S. C. WPAM Auerbach & Guettel..Topeka, Kans. Waco, Texas WNAR C. C. Rhodes Butler, Mo. WLAK WPAP Theodore D. Phillips..Winchester, Ky. Vermont Farm Machine Corp., WNAS Texas Radio Corp. & Austin WPAQ General Sales & Engineering Co., Bellows Falls, Vt. Statesman Austin, Tex. Frostburg, Md. WLAL Tulsa Radio Co Tulsa, Okla. WNAT Lennig Bros. Co.. Philadelphia, Pa. WLAM WPAR R. A. Ward Beloit, Kans. Morrow Radio Co...Springfield, Ohio WNAV Peoples Telephone & Telegraph Co., WPAS J. & M. Electric Co.Amsterdam, N. Y. WLAN Putnam Hardware Co Houlton, Me. Knoxville, Tenn. WPAT St. Patricks Cathedral.E1 Paso, Texas WLAO Anthracite Radio Shop..Scranton, Pa. WNAW Peninsular Radio Club. W. tWPAU Concordia College...Moorhead, Minn. WLAP V. Jordon Louisville, Ky. Fort Monroe, Va. WPAV Paul Tinetti & Sons...Laurium, Mich. WLAQ A. E. Schilling Kalamazoo, Mich. WNAX Dakota Radio Apparatus Co., WPAW Radio Installation Co., WLAR Mickel Music Co..Marshalltown, Iowa Yankton, S. D. Wilmington, Del. WLAS Central Radio Supply Co., WNAY Ship Owner's Radio Service, WPAX S W Radio Co. (J. R. Shumate, Jr.). Hutchinson, Kansas Baltimore, Md. Thomasville, Ga. WLAT Radio Specialty Co Burlington, Iowa WNJ Shotton Radio Mfg. Co., Inc., WPE Central Radio Co...Kansas City, Mo. WLAV Electric Shop Pensacola, Fla. Albany, N. Y. WPG Nushawg Poultry Farm, WLAW Police Dept. of New York City, WNO Wireless Telephone Co. of Hudson New Lebanon, Ohio New York, N. Y. County, N. J... Jersey City, N. J. WPI Electric Supply Co Clearfield, Pa. WLAX Putnam Electric Co.Greencastle, Ind, WOAA Dr. Walter Hardy.... Ardmore, Okla. WPJ St. Joseph College...Philadelphia, Pa. WLAY Northern Commercial Co., WOAB Valley Radio Grand Forks, N. D. WPM Thomas J. Williams, Fairbanks, Alaska WOAC Maus Radio Co I ima, Ohio Washington, D. C. WLAZ Hutton & Jones Electric Co., WOAD Friday Battery & Elec. Co., WPO United Equipment Co. Memphis, Tenn. Warren, Ohio Sigourney, Iowa WQAA Horace A. Beale, Jr..Parkesburg, Pa. fWLB University of Minnesota, WOAE Midland College Fremont, Nebr. WQAB Sonthwest Missouri State Teachers Minneapolis, Minn. WOAF Tyler Commercial College, College Springfield, Mo. tWLK Hamilton Mfg. Co.Indianapolis, Ind. Tyler. Texas WOAC E. B. Gish Amarillo, Tex. tWLW Crosley Mfg. Co Cincinnati, Ohio WOAG Apollo Theatre Belvedere. Ill. WQAE Moore Radio News Station (Edmund WMAB Radio Supply Co Oklahoma, Okla. WOAH Palmetto Radio Corp.Charleston, S. C. B. Moore) Springfield, Vt. WMAC J. Edw. Page (Clive B. Meredith), WOAI Southern Equipment Co., WQAK Appel -Higley Electric Co., Cazenovia, N. Y. San Antonio, Tex. Dubuque, Iowa WMAD Atchinson County Mail, WOAJ Ervine Electrical Co Parsons, Kan. WQAL Coles County Telephone & Rock Port, Mo. WOAK Collins Hdwe. Co....Frankfort, Ky. Telegraph Co Mattoon. Ill. WMAF Round Hills Radio Corp., WOAL Wm. E. Woods.Webster Groves, Mo. WQAQ West Texas Radio Co..Abilene, Texas Dartmouth. Mass. WOAN Vaughn Conservatory of Music, WQAY Gaston Music & Furniture Co.. WMAG Tucker Electric Co....Liberal, Kans. Lawrenceburg, Tenn. Hastings, Nebr. WMAH General Supply Co....Lincoln, Nebr. WOAO Lyradion Mfg. Co...Mishawaka, Ind. WRAA Rice Institute Houston, Texas tWMAJ Drovers Telegram Co.. WOAP Kalamazoo College..Kalamazoo, Mich. WRAN Black Hawk Electrical Co., Kansas City, Mo. WOAQ Portsmouth Radio Assoc., Waterloo, Iowa WMAK Norton Laboratories Lockport, N. Y. Portsmouth, Va. WRAR Jacob C. Thomas...David City, Nebr. WMAL Trenton Hardware Co.Trentort, N. J. WOAR Henry P. Lundskow Kenosha, Wis. WRAU Amarillo Daily News.. Amarillo, Tex. tWMAM Beaumont Radio Equipment Co., WOAS Bailey's Radio Shop, WRAY Radio Sales Corp Scranton, Pa. Beaumont, Texas Middletown, Conn. WRK Doron Bros. Elec. Co.Hamilton, Ohio WMAN Broad St. Baptist Church, WOAT Boyd M. Hamp Wilmington, Del. WRL Union College Schenectady, N. Y. Columbus, Ohio WOAU Sowder Bolling Piano Co., WRM University of Illinois.... Urbana, Ill. WMAP Utility Battery Service...Easton, Pa. Evansville, Ind. WRP Federal Institute of Radio WMAQ The Fair Corp. & Chicago Daily, WOAV Second Battalion, 112th Inf., P.N.G., Telegraphy Camden, N. J. Chicago, Ill. Erie, Pa. tWRR City of Dallas, Police & Fire WMAR Waterloo Electrical Supply Co., WOAW Woodmen of the World.Omaha, Nebr. Signal Dept Dallas, Texas Waterloo, Iowa WOAX Franklyn J. Wolff (Monument WRW Tarrytown Radio Research tWMAT Paramount Radio Corp., Pottery Co.) Trenton, N. J Laboratory Tarrytown, N. Y. Duluth, Minn. WOAY John M. Wilder....Birmingham, Ala. WSAJ Grove City College...Grove City, Pa. tWMAV Alabama Polytechnic Inst., WOAZ Penick Hughes Co...Stamford, Texas WSAS Bureau of Markets, State Dept. Auburn, Ala. "toWOC Palmer School of Chiropractic, of Agr Lincoln, Nebr. WMAW Wahpeton Electric Co., Davenport, Iowa WSAT Plainview Electric Co.Plainview, Tex. Wahpeton, N. Dak. WOE Buckeye Radio Service Co., WSAV Clifford W. Vick Radio Const. Co., WMAX K & K Radio Supply Co., Akron, Ohio Houston, Texas Ann Arbor, Mich. WOH Hatfield Electric Co.Indianapolis, Ind. "toWSB Atlanta Journal Atlanta. Ga. WMAY Kingshighway Presbyterian Church. tWOI Iowa State College Ames, Iowa WSL J & M Electric Co Utica, N. Y. St. Louis, Mo. WOK Arkansas Light & Power Co. WSN Ship Owners Radio Service, Inc., WMAZ Mercer University Macon, Ga. (Pine Bluff Co.)..Pine Bluff, Ark. Norfolk, Va. WMB Auburn Electrical Co...Auburn, Me. "toWOO John Wanamaker....Philadelphia, Pa. WSX Erie Radio Co Erie, Pa. tWMH Precision Equipment Co., tWOQ Western Radio Co...Kansas City, Mo. tWSY Alabama Power Co.Birmingham, Ala. Cincinnati, Ohio "oWOR L. Bamberger & Co....Newark, N. J. WTAC Penn Traffic Co Johnstown, Pa. WMU Doubleday -Hill Electric Co., twos Missouri State Marketing Bureau, WTAU Ruegg Battery & Electric Co., Washington, D. C. Jefferson City, Mo. Tecumseh, Nebr. WNAB Park City Daily News, fWOU Metropolitan Utilities District, Bowling Green, Ky. WTAW Agricultural & Mechanical College, Omaha, Nehr. College Stations, Tex. WNAC Shepard Stores Boston. Mass. tWOZ Palladium Printing Co.Richmond, Ind. Kansas WNAD Oklahoma Radio Engineering Co., tWPA Fort Worth Record. .Fort Worth, Tex. toWTG State Agricultural College, Norman, Manhattan, Kansas Okla. WPAA Anderson & Webster Elec. Co.. WTP George M. McBride..Bay City, Mich. fWNAF Enid Radio Distributing Co. Wahoo, Nebr. WWAC Sanger Bros Enid, Okla. \VPAB Pennsylvania State College. Waco, Texas WNAG Rathert Radio & Electric Shop, State College, Pa. WWAD Wright & Wright, Inc Cresco, Iowa WPAC Donaldson Radio Co..Okmulgee, Okla. Philadelphia, Pa. WNAH Wilkes-Barre Radio Repair Shop, WPAD W. A. Wieboldt & Co Chicago, Ill. WWAX Wormser Bros Laredo, Texas Wilkes-Barre, Pa. WPAF Peterson Radio Co.Council Bluffs, Ia. WWB Daily News Printing Co.Canton, Ohio WNAJ Benson Co Chicago, Ill. WPAG Central Radio Co...Tndependence, Ill. WWI Ford Motor Co Dearborn. Mich. WNAK Manhattan Radio Supply Co., toWPAH Wisconsin Department of Markets, "toW W J Detroit News Detroit, Mich. Manhattan, Kan. Waupaca, Wis. WWr, Loyola University..New Orleans, La. WNAL R. J. Rockwell Omaha. Nehr. WPAJ Doolittle Radio Corp., WWT McCarthy Bros. & Ford.Buffalo, N. Y. WNAM Ideal Apparatus Co..Evansville, Ind. New Haven, Conn. WWZ John Wanamaker...New York, N. Y.

VrovAd You, ArCh5Wer The5e QuerIlee, frOT Two Centg

The following is a letter, copied word for receive from 3,000 miles or less, also show ings and instructions and hook-ups on these word as received from a reader, and me how to hook up both sets not in Radio things I describe, a telegraph set (morse) addressed to the Question and Answer De- symbol but in simple pictures. And how to and and telephone also a Wirless telegraph partment. The reader very kindly enclosed mount on a panel. Send me some of the set and wireless telephone set. and a De- a 2 -cent stamp for the return of this best drawings of high tuning arristers. And tector microphone. Is it possible to make a information. The letter was received on a instructions how to make and hook up with dynamo or electric motor at home. If so Wednesday. Note when he expected a sets, a loud -speaker, a detector amplifier, all send me the drawings and instructions how reply. kinds of knobs and swithes, a frequency to make them. I will be pleased with all the "Dear Sir: transformer, a few types of vernier con- answers at my house on FRIDAY if pos- Will you kindly send me all information densers, a few types of loop aerials, ampli- sible. I give much thanks for all answers. of what I am asking. I would like that you fier set 3 stages to 4, drawings and instruc- Yours truly, would send me drawings and instructions on tions variable plate Battery (22%) volts. making the following things about Radio. Phone con. .002 micro farads or more. Tell A varicouple'r of the best type, a variometer, me a way to make fiber or' baklite dials. P. S. also send me how to make a small also best type, audion and vacuum tube What is "spaghetti" insulation? crystal set. hook-up and parts to make and how to socked, Filament and other type rheostats, As though this were not sufficient, the make the parts at small expense." variable condenser and Fixed cond., .00025 writer continues on another page as follows : Faint cry from the Editorial sanctum: microfarads. can phone receivers be made, Dear Sir: "Quick, Watson! the needle !" if .so send me drawing of a good receiver. I am writing this second letter because I But seriously-what this reader needs is a also a good receiver with instructions to had not enough space on the other paper. I text book. May we suggest the new book make all parts to set. The set which can would like If you would send me the draw- by Mr. H. Gernsback, "Radio For All," 1090 In this Department we publish questions and answers which we feel are of interest to the novice and amateur. Letters addressed to this Department cannot be answered free. A charge of 25c is made for all questions where a personal answer is desired. REGENERATIVE TUNER ONE STAGE RADIO FREQUENCY TWO STAGE AUDIO FREQUENCY AMPLIFIER AMPLIFIER (119) Carl Boehle, Bay City, Texas, says (116) Carl W. Chase, Amsterdam, N. Y., of a (124) Malcolm B. Boyse, Bradford, Mass., re- which gives that he has a receiving set consisting writes that he has an audion detector variable condenser, a vario -coupler, an audion quests: very good results when used with a loose -coupler detector, and two stages of audio -frequency am- Q. 1. Will you please give me a circuit diagram for tuning. He asks: plification. He asks: for a vario -coupler, a variable condenser, one step Q. 1. Will you kindly give me a hook-up of Q. 1. How should I hook these instruments of radio frequency amplification and an audion the amplification appliances necessary to add to up, with the addition of a variometer, so as to detector? this set so that the signals may be heard with a have a regenerative set? A. 1. We give herewith the required diagram. loud -speaker? A. 1. We would advise you to use the circuit A. 1. In order to use a loud -speaker with your diagram published on page 56 of the May, 1922, set you should add two steps of audio frequency issue of SCIENCE AND INVENTION, the only change necessary being that you insert a variometer in the plate circuit of the detector tube. In other words, disconnect the plate from the primary of the first transformer, and connect the latter to one side of the variometer. Connect the other side of the variometer to the plate, and you will have a regenerative circuit. This circuit, however, can be greatly improved by inserting another vario - meter in the grid circuit of the detector tube.

RADIO -FREQUENCY AMPLIFICATION (120) C. E. Blair, Jr., Laramie, Wyoming, wants to know : Q. 1. Is it possible to apply radio -frequency amplification to a short wave regenerative set? A. 1. Radio -frequency amplification may be applied to any sort of regenerative tuner by placing the radio -frequency amplification before the tuner and connecting the input of the first tube of radio -frequency to each side of a tuning coil, one side of which is connected to the ground, and the other side of which is connected to a variable condensercondenser._ which in turn is con- nected to the antenna. output of the radio - frequency amplifiers is connected directly to the A circuit diagram of a tuner and one stage aerial and ground binding posts on the regen- of radio -frequency amplification, together with Two stages of audio-frequency amplification erative tuner. If there is a variable condenser an audion detector, is shown above. may be added to any receiving set, by using embodied in the tuner in series with the antenna the circuit shown above. lead, this should be short-circuited, or in some other way eliminated entirely from the circuit. amplification. A circuit diagram of the same is It may be found to advantage to connect this con- LOUD TALKER QUERIES given herewith. of the tuner denser across the primary coil E. Paul Hunt, Orrick, Mo., wants to proper. (125) CONDENSER CAPACITIES know: (117) Frank A. Hackert, Bellingham, Minn., Q. 1. How much and what size wire should ANTENNA AND RECEIVING RANGE be used for winding the field -coils of a double asks: to a Magnavox? Q. 1. What capacity should the condensers QUERIES pole loud talker similar enumerated below have for use in a short wave A. 1. Three pounds of No. 17 S. C. C. wire consisting of a vario -coupler and (121) B. A. Hoduct, Memphis, Tenn., in- should be used on each core for the field coils, and regenerative set of 18 feet of No. 38 a variometer? Series antenna condenser, second- quires: the moving coil should consist ary condenser, and grid and phone condensers. Q. 1. Would an antenna 300 feet long answer S. S. C. or enameled wire. may for the reception of radiophone Q. 2. What size diaphragm would you recom- A. 1. The following condenser capacities satisfactorily material and be used with your short wave regenerative tuner. broadcast? mend for this loud -talker, and what Condenser in series with aerial .001 M. F. A. 1. A 300 foot antenna would be much too thickness? Condenser across secondary .001 M. F. long for 360 meter reception, and we would advise A. 2. A 3 -inch diaphragm should give very sat- Grid condenser .00025 M. F. you to cut it down to about 100 feet. isfactory results, and we would advise you to F. 2. How far could I hear with the above an- try snaking it from sheet iron .006 inch to .007 l'hone condenser .0165 M. Q. in Q. 2. Is it necessary to use a rheostat to con- tenna and a short wave regenerative tuner used inch thick. trol the filament current and a potentiometer to connection with a single audion tube? Q. 3. Could a standard audio -frequency am- control the plate voltage of a vacuum tube? A. 2. Your consistent receiving radius with a plifier transformer be used as the step-down A. 2. A rheostat must be used to control the single tube should be 60 to 75 miles for radio- transformer with this loud -talker? filament of your tube for best results, and a poten- phone. A. 3. You might try using an audio trans- tiometer is desirable, but not absolutely necessary Q. 3. Would a loading coil increase the range former in connection with this loud -speaker, but to control the "B" batteries. of this set? we would also suggest that you write to the Mag- A. 3. The addition of a loading coil to the navox Company regarding the purchase of a dif- DETECTOR AND ONE STAGE AMPLIFIER above set would not add to the receiving range in ferent type of transformer suitable for use in (11g) Edward Claus, Pittsfield, Ill., asks for a the least, but would merely increase the wave tills connection. circuit diagram of the following apparatus, to- length. gether with any necessary additional apparatus. SINGLE HONEYCOMB COIL TUNER One variable condenser, three honeycomb coils, two RANGE a 6 volt RECEIVING (126) Harold T. Jones, Oshkosh, Wis., asks: vacuum tubes, two 22V volt "B" batteries, honeycomb storage battery, two sockets, two rheostats, grid Holmes, Princeton, Mo., refers to Q. 1. How can I hook up a single (122) Rex with a variable condenser so as to make an leak and condenser, and phones. a set described in a back issue of this journal coil apparatus you mention an audion detector. efficient receiving tuner? A. 1. In order to use the which consists of a tuner and herewith the diagram as re- you will need one more variable condenser and one He asks: A. 1. We give transformer. set be used successfully to re- quested. The "B" battery should have a voltage amplifying Q. 1. Can this should be a "soft" or de- We are giving herewith a circuit diagram of ceive frons a transmitting station located 125 miles of 22%, and the tube your apparatus, including the two above mentioned from my home? ector tube. instruments. A. 1. With the set you mention you might pos- sibly be able to receive over a distance of 125 miles, but we would advise you to use at least one step of audio frequency amplification. AERIAL- Q. 2. Of what use is the rheostat in the fila- ment circuit of the vacuum tube? HONEYCOMB COIL A. 1. The rheostat in the circuit is used to regulate the amount of current passing through the filament of the tube. DIFFICULTY IN RECEPTION (123) Lyman Hanes, Minneapolis, Minn., asks: Q. 1. Can you explain what is causing the difficulty in receiving wireless telephone messages from Chicago, Milwaukee and Duluth in Minne- apolis? A. 1. Not knowing anything about the local conditions in Minneapolis, nor the kind of re- ceiving apparatus used, it is impossible for us to say just why you are not able to receive messages from Chicago, Milwaukee and Duluth. GRID LEAK&COND. You must realize that there are many factors Its messages, entering into the reception of radiophone TO STORAGE BAT. RHEOSTAT HONEYCOMB COILS 'f' some of which are local topographical conditions, TO GROUND type and location of antenna used, and -the quality of the receiving set. and sensitiveness for use with an audion de- coil circuit employing a If there is any particular type of apparatus A simple tuner A three honeycomb will give ns tector, is shown herewith. The size of the one stage amplifier, is shown above. Greater which you have in mind, and you to more details, we will be only too glad to help you honeycomb coil can be varied according selectivity can be obtained by shunting the the wave length it is desired to receive. secondary coil with a variable condenser. as far as possible. 1091 Fountain Toothbrush etc., but in our opinion such a pro- cedure Polyphone Sound Box shaped piece of metal connects two (No. 1,436,883, issued to Charles J. would cause an arc to form of the outside between the contacts, as the circuits (No. 1,438,642, issued to John binding posts together Koepke) were being and grounds them. One or both of This inventor opened. A quick acting Graham) the remaining has developed the thermostat would be necessary. This two outside posts are fountain toothbrush idea consider- invention is ingenious be- then connected to wires leading to ably. He employs a casing with a the ignition system. By this method Reducing Valve an intensifying spark l(No. 1,437,437, plug is pro- issued to Luigi duced, the spark leaping from one Mombaruzzo) of the outside posts to the center If a law were passed to make it and thence to compulsory a post on the opposite to employ gas valves or side, viz., to the ground. In a plug the nature described herewith, we of this nature, the possibility of its can be sure that accidents resulting fouling is supposed to be practically in the loss of life from gas leakage eliminated. would be rare. People contemplat- ing suicide will have to do so by deliberately removing the tip of the Wave Power Motor gas burner. Within the tip, one end of a metallic thermostat (No. 1,439,849, issued to Edward D. bar is found. Stodder) suitable slot therein One end of this bar is secured to a cause of the fact that the inventor (to permit the partition and employs two In this patent introduction of the fingers) to house suspended from the sound boxes connected (the principle of a tooth paste tube. This other end is a ball which, when to the same tone arm, each of which has been explained in an ar- casing is the thermostatic metal which is ticle appearing several provided with a threaded portion at is cold, fits provided with its own years ago in its neck, into which into a recess in the partition, clos- stylus. Both of these stylus' fitting this journal), the inventor provides the tooth paste ing the aperture into for a series of piers tube is screwed after the cap has thereof. A tiny the same groove in the record, or columns of been removed. From reproduce the music therefrom. but the opposite due end of this a rod containing the to the fact that there are two bristles of the diaphragms acted upon each by the toothbrush projects, same and immediately below this an elon- energy, much louder music is gated tube may be found through claimed for the device. In order which the tooth that one stylus shall follow the paste is to ooze other when pressure is exerted upon the into the same groove in the tube. An outer casing surrounds record, the inventor employs two the previously mentioned casing, arms which orientate the sound box, which is also provided the latter rotating upon the tone with a slot, arm. so that when partially rotated, the fingers may be introduced through the two slots now in juxtaposition with each other. A cap covering the Control Mechanism for bristles, also contains a needle adapted to fit Headlights into the tube through (No. which the tooth paste is to pass. 1,433,080 issued td Edward B. Working this pointed wire back and Kaylor) tJ i i forth, dislodges any tooth paste An automobile provided with the I i which may have caked while the by-pass aperture is also found, usual headlights, has these headlights 1....1 brush was lying idle. through which gas escapes at all so arranged that they may concrete or steel. times when the main be tipped Floats are secured cock is turned downwardly or directed straight between these, the floats have on. In order to light ,the burner, ahead. Rods connect limited lateral a Swimmer's Motor gas permitted to escape both headlights movement, but are (No. through the with a cross -arm, and thence by permitted to ride up and down 1,433,563, issued to Lyman P. tiny by-pass is lit; the heat trans- means of right angle comparative in Osterhout) mitted to the levers and rod freedom. All actions of thermostat opens the the waves are taken into considera- This is undoubtedly one of the valve fully. tion, that is, not cheapest swimmin only is the gravi- devices which tational influence employed, but the Submarine Signaling lifting action of the wave is also Apparatus used to actuate drums. These drums (No. 1,440,361, issued to Frank in turn operate air compressors Lloyd Hopwood) which store the energy for driving A double casing containing a dia- turbines and electrical generators, phragm for each portion and the horizontal effect produced of the by steep casing, that is, four diaphragms in waves is also employed in all, also houses a microphone con- developing power necting to the ship by means of ca- bles and to the receiving instru- ments. Sounds in the water can Aerial Vessel has now be picked extensions (No. been designed up to the present up by the microphone to a controlling clutch, op- 1,432,209, issued to Robert C. time. It consists of a belt surround- and an individual at the receiver erating about a notched sector se- Rimmer) ing the body of the swimmer, can interpret them and in that way curely fastened to the steering wheel In this airplane, an inflatable with of the automobile. the propellers buoyant cushion at its For driving on are arranged in the form of paddles lower point, which also acts as city streets, the headlights of the much the retainer for the automobile are same as in side -wheel a bearing post, through directed downward, steamships. The orientation of which bearing a propeller shaft so that the rays of light which may thu passes.. The second buoyant float be brilliant at all times (eliminating has erected upon it a driving gear entirely the use of the dimmer), and a right angle transmission gear, flood the ground in front of the ve- fastened directly to the propeller hicle with a pure light. None of the shaft. By means of this apparatus rays are permitted to pass out even comparatively great speed can be on a horizontal plane. When the obtained by an unskilled swimmer. headlight is raised the beam is di- rected straight ahead as usual. Electric Circuit Breaker (No. 1,438,308, issued to George F. Hunter) Spark Plug In this electric curling iron, the (No. 1,441,397, issued to William H. resistance element is contained with- Chard and in the iron casing William F. Hills) which extends This specification downward into the handle of the gives the de- iron. This causes the temperature scription of an unusually novel de- within the handle to rise consider- parture from the ordinary run of ably, which spark plugs, for internal combustion in so doing acts on the engines. thermostatic bar, and when the heat determine The inventor proposes to is high enough the nature of the ship run preferably five rods through in- blades causes this to bend causing the sounds. By varying the sulating material, is accomplished by means of outwardly and open the electric cir- distance between such as porcelain, a cam located off center, which the diaphragms, in such a manner that one of the ing upon act- not only is the sensitivity and the rollers and thence through tuning varied, intermediary levers, causes but by different ad- blades the fan justments of the two sides the direc- to assume certain definite po- tional effect sitions relative to the desired of the instrument is ob- ments move- tained. The space between the dia- of the airplane. The inven- phragms may be filled with tor of this device claims to have or liquid built a working model, cuit. some jelly -like material. Screws which has As soon as the temperature permit the area in experimentally proved that flight can of the iron drops which the micro be accomplished down again, the phone lies to be broadened or con- by a machine of his circuit is closed and the iron con- tracted, causing the design. These same paddles also tinues to heat. The inventor different prop- permit the states erties of the microphone to be rods will constitute airplane to be directed that this same system could be em- brought the center elec- ahead or astern, depending ployed for out for better tuning and trode, and the other four will be upon: the electric flat irons, ovens, sharpness of signals. arranged location of the cams, and their ef- around this center. A T- fect on the revolving blades.

1092 The "Oracle" is for the sole benefit of all scientific experimenter. Questions will Le answered here for the benefit of all, but only matter of sufficient interest will be published. Rules under which ques- tions will be answered: 1. Only three questions can be submitted to be answered. . 2. Only one side of sheet to be written on ; matter must be typewritten or else written in ink. no penciled matter considered. 3. Sketches, diagrams, etc., must be on separata sheets. Questions addressed to the department cannot be answered by mail free of charge. 4. If a quick answer is desired by mail, a nominal charge of 25 cents is made for each question. If the questions entail considerable research work or intricate calculations a special rate will lie charged. Correspondents will be informed as to the fee before such questions are answered.

MAKING PERMANENT MAGNETS HARDENING LEAD the stick for the cap and fuse. In fact, a well (1415) J. Bartlett, East Toronto, Canada, in- known explosive manufacturing company, in their (1411) B. L. Rites, Asheville, N. C., inquires: quires: directions for using dynamite, show the holes Q. 1. Can soft lead be made hard by dipping being punched with the end of the handle of a ,Permanent it in a chemical solution? cap crimper or with a wooden awl. A. I. 'There is no method of hardening lead magnet. by dipping it into a chemical solution. There is ATMOSPHERIC POTENTIALS said to be a secret process by means of which (1419) A. Chapple, Vancouver, B. C., Canada, lead may be made hard enough to be used in asks: making knives, and other instruments requiring Q. 1. If the electrical potential of the air a hard metal. We have no information on this varies according to the height, would not a charge Electro-mognets process, however, as the inventor has kept it an collect upon a metal plate placed at a height, and absolute secret. would not a current flow from this along a wire to the ground, or vice versa? this is so, why 1 If STEEL SUPPORTING ARM could we not place a vibrator in the connecting wire, and so get a pulsating current from the air? (1416) Chas. E. Burrell, Shamokin, Pa., says: A. 1. The experiments you mention have been 1 would like to make an arm of steel 50 feet tried time and again, but it has not been found long to support a weight of 500 pounds with practical to draw electricity from the air by absolute safety. One end is to work up and down the method you suggest, because the amounts ob- in a groove, and the other end is to be supported tainable vary considerably in strength and regu- by a wire rope. He asks: larity. An example of drawing electricity from Q. 1. Can you tell me how to construct this the air may be seen in any large radio station. arm of steel, and how heavy must it be? For instance, at the station of the American Tele- A. 1. The arm of steel which you describe phone & Telegraph Company in New York City, will depend entirely on the construction and cross it is possible at times to draw sparks 1 inch long bracing. You will find that a latticed steel arm from the lightning switch when the same is left will be much lighter than a solid steel arm in a open. This is because of the static electricity derrick similar to the one you describe. This lat- which has collected on the antenna.

111 111111 111111111 1r111,1111111,,,,1111111111 11,1 , 11 1 111111111111111,11111111,,,1111111111111,1,11,,1,,,,,,, COLLECTING MOISTURE FROM THE AIR To power mains and (1420) M. A. Raymond, Washington, I). C., circuit breaKer. wants to know: Articles Q. 1. How may the moisture which is con- The method of magnetizing permanent horse- tained in the form of vapor in the air of a room, shoe magnets is shown above. having a humidity of approximately 75 to 90 in March degrees, be collected? Q. I. How are permanent horse -shoe magnets 6aPractIlCCaIl ERect&'Ilcsvs A. 1. Since you did not give us definite infor- magnetized in quantities? mation as to the size of the room in which you A. 1. Any' large sized electro -magnet, operat- wish to extract the moisture from the air, we can ing on a heavy direct current, may be used for New Theory of Magnetism only give you suggestions. For instance, place titis work. We are giving you a diagram here- a quantity of calcium chloride in each of four with showing how the permanent magnets should porcelain dishes, and place them in various parts he placed, one at a time. It is advisable that the Electrical Pumps of the room. The calcium chloride will absorb direct current supplied to the large magnets be By F. I?. Kingman moisture from the air, and if you wish to abstract interrupted rapidly. the water from the same, you may do so by placing the chemical in a retort and heating it, ELECTROLYTIC RECTIFIER Home Battery Charger collecting and condensing the water vapor given off. This will probably be the simplest way to (1412) John M. Ramsey, Detroit, Mich., asks: obtain the results you desire. Q. 1. What is the resistance of a standard Three Brush Automobile Genera- solution of ammonium phosphate such as is used tor. By H. Highstone REDUCING VOLTAGE in an electrolytic rectifier? A. 1. To all practical intents and purposes, the (1421) A. A. Rynkiewicz, Techny, Ill., says: resistance of such a solution is practically negli- Motor Without Visible Field I have some wire, the resistance of which is gible. resistance is about 1% ohms varying 125 ohms per foot. He asks: Its Q. 1. How can I make use of this wire to with the temperature. It is for this reason that Planting Vines by Electricity in using the electrolytic rectifier, it is absolutely reduce 110 volts to 50 volts? necessary that some suitable form of resistance be A. 1. If you will stretch one foot of wire the ,11111111111111,111111.,,,41,,,11.,,,11111111,111111111111111111111111111111111,,,.1,1.t. ,,,,,,,II,,,u,,,11111111, between two insulators, then take off a tap near inserted in series with the rectifier and source re- of current, as otherwise the fuses will the center as illustrated, you will be able to alternating duce 110 volts A. C. to 50 volts. Eleven inches blow out. A resistance of about 20 ohms, cap- ticed steel arm sufficiently cross -braced and welded every inch 5 is necessary when of the wire might be used, whereupon able of carrying amperes, or riveted, will not be so hard on the bearings. 10 at a 5 ampere would constitute a tap delivering volts. With charging a 6 -volt storage battery We would suggest that you communicate with of is 15 capable of carrying 8 his arrangement the regulation the voltage rate, while about ohms, various concerns regarding breaking and bend- very simple, but very little current would be amperes, should be employed for an 8 ampere on steel girders. Also request that rate. ing stresses available, due to the high resistance, and the they figure on various types of arms, such as T - microscopic thinness of the wire. arms, I -beams, triangular cross -braces, and four- CONVERTING GASOLINE SAD IRON TO sided cross -braced arms. They will give you all ELECTRIC of the figures available. (1413) Henry Rodenmayer, Clermont, Fla., asks: CHEMICAL IGNITION Q. 1. How can I convert a gasoline sad iron (1417) Thos. A. Caplen, Detroit, Mich., in- into one operated by electricity? quires: A. 1. To convert a gasoline sad iron into an Q. 1. Is there any chemical substance which electric iron, it will be necessary to remove the will, when lightly rubbed, produce a hot flame burner on the inside of the same, and line the without any disagreeable fumes or odors? iron with asbestos. Then go to any electrical sup- A. 1. There is no chemical substance, to our ply store, and purchase a heating grid, such as is knowledge, which will give a hot flame when sold for renewals in electric irons, and place the lightly rubbed, without producing any disagree- same within the iron you have. Two flexible able fumes. Phosphorous will produce a high leads, well insulated by asbestos, are brought out degree of heat when ignited by rubbing. it is from the iron, and the job is done. dangerous to work with continually as the white phosphorous attacks the osseous system. VOLTAGE DROP HANDLING DYNAMITE (1414) Louis T. Roberts, New Orleans, La., asks: (1418) Clarence Chittenden, Perry, Iowa, be the voltage drop over says: I have been told that dynamite has been Q. 1. What would hole in the á line consisting of two No. 10 B. & S. gauge known to explode when punching a wires one mile long, the current being 4 cartridge for the insertion of the cap and fuse. copper He asks: A potential of one hundred and ten volts may amperes at 110 volts? volts shown 10 copper wire Q. 1. Has an authentic case of such an ex- be reduced to fifty by the method A. 1. The two lines of No. above. Very little current will be delivered on stretching for a distance of a mile, will create plosion ever been reported? 10 volts, provided A. 1. We do not know of any case where the fifty volt side, owing to the small wire a drop in potential of about hole in used in this case. that the lines are insulated. dynamite exploded when punching the 1093 1094 Science and Invention for March, 1923 DATA ON THE SOLAR SYSTEM A. 1. What you suggest could be very easily or stove size, deteriorate in (1422) G. A. done by heat producing power Steinmiller, Chicago, Ill., wants means of movable core solenoids which on being kept in an open bin in : could a cellar for a to know be used to raise the arms of the signals, period of eighteen months? Q. 1. Can you give me the following informa. the particular ones to be raised being selected tion on the planets Mercury, Venus, Earth, Mars, by means of a switch. Small circuit -closers could A. 1. The percentage of loss under the circum- Jupiter, Saturn, Uranus and Neptune? Their be arranged to operate in connection with the stances is very slight if coal is left in a dry bin diameters, distance from the sun, time required for solenoids, so that just as the solenoids start to in a cellar. one revolution around the sun, and time re- raise the levers, the light will light, and It is reported that lever as the coal submerged in sea water quired for one revolution on their axes. rises further, the light will go out. The gives a greater number of B. T. U.s than if left A. 1. We give herewith the desired infor- size and amount of wire used on the solenoids in the open air or if burnt immediately after be- mation, in which the length of the year repre- will depend upon the current used, and can easily ing taken from the coal mines. There are no sents the time required for one revolution around be determined by experiment. accurate figures which can be given because dif- the sun, and the length of day, the time re- ferent tests will produce different efficiencies even quired for one revolution on the axis. The FOUCAULT'S EXPERIMENT though the coal is taken from the same shipment. measures of time given are the standard hour, day (1427) M. Brieger, Montreal, and year of the Canada, asks: earth. Q. 1. Will you kindly explain what the ex Changing the Color of Man Name Diameter periment involving Foucault's pendulum consisted Distance from sun of? (1431) Mercury Edgar D. Walker, Chicago, Ill., wants 3,030 miles 36,000,000 miles A. 1. We quote from Flammarion's ASTRON- to know: Venus 7,700 miles 67,200,000 miles OMY FOR AMATEURS. Earth 7,917.6 "The magnificent ex- Q. 1. If there has ever been performed an op- miles 92,900,000 miles periment of Foucault at the Pantheon, just re. eration Mars 4,230 miles 141,500,000 miles newed under on a person of colored origin, in order the auspices of the Astronomical to make him have a white skin. Jupiter 86,500 miles 843,300,000 miles Society of France, demonstrates the rotary motion Saturn 73,000 miles 886,000,000 miles of the Earth to all beholders. A. I. An attempt to change the color of a Uranus 31,900 1,781,900,000 A sufficiently heavy man miles miles ball (28 kilograms, about 60 pounds), is suspended by means of glandular extirpations has never Neptune 34,800 miles 2,791,600,000 miles from the dome taken place. Medically we know that there are Name of the edifice by an excessively Length of year Length of day fine steel thread. When the pendulum is in mo- certain glands whose secretions cause pigmenta- Mercury 88 days 88 days tion, a point tion of the skin. If these glands Venus attached to the bottom of the ball could be re 225 days uncertain marks its passage upon two little heaps of sand moved prior to birth, it is quite probable that Earth 365 days 24 hours arranged some we could get a lack of color not Mars yards away from the center. At only in the 687 days 24% hours each oscillation this point cuts the sand, and the pigmented layer of the skin, but also in the hair, Jupiter 12 years 10 hours furrow gets gradually longer to the right hand of eyebrows, nails, and all other parts of the body Saturn 29'/2 years 10% hours an observer placed which are a direct outgrowth Uranus at the center of the pendulum. of the ectoderm. 84 years uncertain The plane of the oscillations remains fixed hut We also know Neptune 165 years uncertain the Earth that certain diseased conditions revolves beneath, from West to East. bring on a marked pigmentation of the skin, and Q. 2. Has there ever been, or will there ever The fundamental principle of this experiment is that if these conditions are he, a time when all the planets will that the plane in alleviated, the skin be on one which any pendulum is made pigmentation disappears. Although the effect of side of the sun and in a straight line? to oscillate, remains invariable even when the which point you speak has been theorized upon, we A. 2. To the best of our knowledge, there has of suspension is turned. This demonstra- do not know of any attempts that have tion enables us in some measure to see the Earth been made been no time when all the planets were in a turning upon either animals or man in an effort to change straight line, nor do we believe that such a thing under our feet." the color of the skin. is possible, due to the varied speeds of rotation Perhaps some experiments around the sun, and inclinations of the planes of with the electric the ecliptics. needle tending to bleach the pigmented skin layer, IMPORTANT following the technique used in the removal of TO birth marks, would he effective in changing the DETECTING DIAMONDS WITH X-RAYS NEWSSTAND READERS color of an individual. (1423) H. S. Bash, Kenton, Ohio, asks: order to eliminate all waste and un- Q. 1. How is a fluoroscope used in detecting INsold copies it has become necessary to diamonds which are being stolen and carried out supply newsstand dealers only with the ac- Fire Resisting Cement tual number of copies for which they have of the mines by workmen in the diamond fields? (1432) Ray J. Cook, Fort Worden, Wash., re- A. 1. One of the methods used for detecting orders. This makes it advisable to place quests: an order with your newsdealer, the theft of diamonds at the mines, is to examine asking him Q. I. Can you give me directions for making the workmen with X-rays. Of course, a fluoro- to reserve a copy for you every month. asbestos cements? scope is used to make the X-ray image visible, Otherwise he will not be able to supply and this is the type as is used in any regular your copy. For your convenience, we are A. 1. Ground asbestos may be made into a appending herewith a blank which we ask cement which will stand a high degree of heat X-ray work. by Q. 2. Will a fluoroscope display activity when you to be good enough to fill in and hand simply mixing it with a solution of sodium acted upon by diamonds? to your newsdealer. He will then be in a silicate. By subsequent treatment with a solution A. 2. No. position to supply copies to, you regularly of calcium chloride, the mass may be made in- every month. If you are interested in soluble, silicate of calcium being formed. THE HECTOGRAPH receiving your copy every month, do not A cement which will stand a high degree of fail to sign this blank. It costs you noth- heat, and be suitable for cementing glass. por- (1424) J. C. Chess, Des Moines. Iowa, asks: ing to do so. Q. 1. Can you give me complete directions celain, and other vessels intended to hold cor- for making a hectograph? rosive acids, may be made as follows: A. 1. We are giving the desired information Asbestos To 2 parts herewith : Melt together one part of glue, two Newsdealer Barium Sulphate 3 parts of water, and four parts of glycerin, all by Address Sodium silicate 2 " weight, evaporating some of the water, and tem- Please reserve By mixing these ingredients, a cement capable pering the mixture with more glue or glycerin, for me copies of of resisting the as the season or climate requires. The mass, SCIENCE & INVENTION every month strongest nitric acid will be ob- until I tained. If hot acids are dealt with, or the cement when of proper consistency. which can be ascer- notify you otherwise, and greatly is to tained by cooling a small portion, is poured into oblige, be used in places where it will be sub- a shallow pan and allowed to stand. Clean glue jected to intense heat, the following will be must be used or the mixture must be strained. Name found to possess still more resistant powers. and air bubbles must he removed by skimming Address Sodium silicate 2 parts the surface with a piece of cardboard. Fine sand 1 " go g g gegagatereggloggme gel A variation of this formula is: Powdered asbestos 1 " Gelatin 10 oz. Both of these cements take a few hours to set. Water 40 oz. Combination of Weights ff a cement which will set immediately is wanted, Glycerin use potassium 120 oz. (1428) Everett Thomas, Casper, Wyo., silicate instead of sodium silicate. Barium sulphate 8 oz. asks: This mixture will set at once, and the Q. 1. If a live fish, weighing 2 pounds resultant Q. 2. What kind of ink is best for is cement will have the same power of resistance use with placed in a vessel containing enough water for that as the above? it to swim in, will the vessel made with the above formula. A. 2. The best ink weigh 2 pounds for use with a hectograph heavier than it did without the fish? Please is purple aniline ink, prepared especially for this explain. SPARK COIL DATA purpose. This may be made as follows: A. 1. If a live fish, weighing 2 (1433) Edward Kujanik, Methyl violet 2 parts pounds is 62 Bruce St., Galt, placed in a vessel containing enough water to Ont., Canada, asks: Alcohol 2 parts allow the fish to swim, and supposing Sugar 1 that the Q. 1. Can you give me data part vessel weighs ten pounds, with the on the construc- Glycerin 4 parts water con- tion of a small spark coil capable of giving a tained within it, when the fish is introduced, the Water 24 parts vessel spark about % of an inch long? Dissolve the violet in the will weigh twelve pounds, the reason being alcohol mixed with that a floating body sinks until it A. 1. The core of such a coil is composed of the glycerin ; dissolve the sugar in the displaces its water, and own weight of the liquid in which it floats. a bundle of iron wires three inches long, the mix both solutions. diameter of the bundle to r/4 If this displaced liquid could flow out of the be inch. The pri- vessel freely, mary consists of two layers of No. 23 D.C.C. COATING COPPER WITH MERCURY so that the same level would be wire, maintained, the weight of the vessel and contents over which is placed an insulating tube. (1425) K. Faulkeper, Winnipeg, Manitoba, would not increase. wills walls 1/32 inch thick. Several layers of Canada, asks: Empire cloth may be substituted for this tube if. Q. 1. What is the best way to coat copper desired. The secondary consists of % pound of with a silver covering of mercury? Perpetual Motion(?) No. 34 enameled wire. The condenser consists A. 1. of 30 sheets 2 To coat copper with mercury you should (1429) J. Stiriss, New York City, says: of tin foil inches by 1 inch, sepa- first clean the surface of the copper thoroughly Imagine rated by sheets of paraffin paper. The primary a machine that is actuated by power de- voltage with weak nitric acid and then rub the quick rived from a chemical compound, which needs should be 2. silver on the clean surface until the desired finish but a little water, say a pint is obtained. a day, to compen- sate for evaporation only, the chemical itself sup- SOURCE OF HIGH AMPERAGE Q. 2. Can this finish be made permanent? plying power and lasting indefinitely. A. 2. It will be impossible to "set" He asks: (1434) John H. McMillen, Iowa this finish Q. 1. Would such a device be perpetual mo- Falls, Iowa, and if you wish to obtain a permanent silvered tion? asks: surface, you must electro -plate the copper article A. 1. Q. 1. Would it he possible with silver. When you figure on a machine actuated to re -wind a low by power from a chemical compound, and state voltage dynamo in order to use it for an electric that only a little water is added to compensate arc welding machine with a maximum capacity ELECTRIC SIGNALS for evaporation, such evaporation of about 150 amperes (1426) could be pre- Wm. D. Foster, Mamaroneck, N. Y., vented by enclosing the device completely. It A. 1. You cannot re -wind a low voltage dy- asks: will not be perpetual motion. namo and use current from the same on an arc Q. 1. How can I raise, electrically, two or welder, with a maximum four vertical levers, two capacity of 150 amperes. at once, or four at Losses in Allowing Coal to Stand There is no low voltage dynamo on the market once, to a horizontal position, the levers being which you can use for this purpose. about 4 inches long, each lever having a small (1430) Nathan Truman, Bainbridge, light at the outer end? I want N. V., We would suggest that you equip your plant each. of the asks: with the alternating lights to show just before raising the levers: Q. 1. Will current, and then step this ordinary anthracite coal in chestnut down to the desired voltage and amperage. Science and Invention for March, 1923 1095 FIRST FOR PRICE, QUALITY AND SERVICE. WE SAVE YOU MONEY MAKE YOUR SET WITH GREAT LAKES QUALITY PARTS WE PAY TRANSPORTATION CHARGES IN THE UNITED STATES AND U. S. POSSESSIONS VACUUM TUBES PHONES OUR GARANTEE YOUR PROTECTION Genuine Cunningham or Radio- Genuine Frost and tron made by the General Elec- Your satisfaction guaranteed. If for any reason you do not feel satisfied tric Co. Every tube guaranteed Brandes head sets money. We 'complete with cords. with your purchase, you may return it and we will refund your new and in original package. will pay return transportation charges. We do not sell 'bootleg" tubes. 0 Frost - 1162 - T -C200 -Detector $4.40 Double head sets, T -C201 -Amplifier 5.90 2000 ohm $4.25 180' VARIOCOUPLER VARIOMETERS Frost T163 The primary and secondary For efficiency, perfect inductive METAL AND double head sets,- windings of this coupler are ratio, low capacity effect and BAKELITE SOCKETS 3000 ohm 4.90 properly proportioned and neatness of design these vari- Bakelite brow n spaced. The center of the ometers are unexcelled. All finished socket for T168 - Western secondary is always in the metal parts nickeled brass. Electric latest finish. panel or base type double head center of the primary Held. Stator and ball mahogany mounting. Double Unlike most couplers, it Furnished completely assembled spring contacts set. List $12.00 fibre and tested. Our price $10.50 aids in tuning. Black held rigidly i n lase, brown formica tube and T1200-Variometer, No. 20 wire 52.65 place. Brandes Superior 7166 -Double head seta mounting. T1300-Variometer, No. 18 wire 2.65 nickeled metal parts. Panel or table T 1 076 -Bakelite 2000 ohm 7.20 71100 -Coupler $2.75 The following knocked -down variometers have socket the stator windings wound and cemented ready $0.65 180° MOULDED ROTOR TYPE T1075-Nickeled to put in place. Two sizes of wire as listed. metal socket .45 COUPLER Complete with wire and metal parts. This 180 degree variocoup- 11205-Knocked -down variometer with MAGNAVOX ler has heavy black tube No. 20 wire $1.85 WD11 WESTING- The genuine 11-3 Radio and moulded rotor ball. 71305 -Knocked -down variometer with HOUSE TUBES Magnavox with the 14 inch Wound with green silk No. 18 wire 1.85 This tube eliminates storage batteries horn is the ideal loud wire and has 10 taps on F. MOULDED TYPE and is operated by a 1% volt dry bat- streaker for use in homes the primary. Metal parts jig's tery. It can be used in any tube hav- offices, amateur stations, are brass nickel plated. VARIOMETER ing the proper socket or adapter. etc. It operates from your Furnished without base. This variometer is made of $5.90 r volt storage "A" bat- but can be mounted on high grade black moulded T 11 -Tubes tery and amplifies as it panel or table. composition. Wound with reproduces. "B" battery TI 120-Variocoupler $3.75 green silk wire. Metal parts WD11 BAKELITE Voltage should be 90 to are nickel plated. SOCKET 200 for best results. VARIABLE CONDENSERS T1220 -Moulded vario - This socket is to be used with -Radio brings it, Mag- Very best mechanical meter $4.95 the above tube. construetion. Heavy, socket. navox tells it." hard aluminum THORDARSON AUDIO 11077 -Bakelite $0.75 T 170 -Radio Magnavox plates. The vernier FREQUENCY AMPLIFYING WD11 ADAPTER $39.50 types are furnished TRANSFORMER The purpose of the adapter is with moulded dial to make your regular socket for There is probably no bet- and small knob ter known transformer. Made usable for a WD11 Tube. adjusting ver- 11078 -Adapter $0.80 nier. Plain types by a company that specializes have Y inch shaft. in transformers. Entirely en- VACUUM TUBE RHEOSTATS cased in sheet aluminum This is a reasonably priced. =7;2e2 eleee T1443-43 plates .001 Mfd. without dial.$2.25 shield. Heavy connecting T1423-23 plates .0005 Mfd. without dial 1.75 smooth acting rheostat that will FROST JACKS AND PLUGS straps to binding posts. mount directly on back of panel. T1411-11 plates .00025 Mid. without T1504 hor Jacks are nickel, nickel -silver springs. dial 1.35 -T darson Bakelite arrow knob. polished without dial 1.15 Transformers, 3% to 1 $3.65 T1050-Rheostat 45e pure silver contacts. Nickel washers for mount- 71403-3 plates .00005 Mfd. T1505-Thordarson Transformer, 5% to 1.$4.20 ing on any panel 1-8 to 3-8 inch thick. Spread 71441-41 plates vernier .001 Mfd. withdial Genuine Cutler -Hammer rheo- terminals make soldering easy. 4.95 AUDIO FREQUENCY stats, we believe, are the best 1133 -One spring (open circuit). Each.$0.46 71442-21 plates vernier .0005 Mfd. with AMPLIFING TRANSFORMERS rheostats on the market today. dial 4.25 Arranged for panel mount- 7134 -Two spring (closed circuit). Each. .52 Correctly designed T 131 -Four spring (two closed circuits) for mini- ing. The picture shows Each .63 THORDARSON VERNIER mum distributed capacity and the vernier type All metal T135 spring (two open circuits, low core loss. Shielded, beau- parts nickeled. Plain type -Three CONDENSERS tifully finished in nickel and is similar. commonly called "single circuit filament T 1523-23 plate vernier .0005 Mfd. with control"). Each .70 black enamel. Ratio 5% to 1. and dial $3.65 71506-Shielded Trans- 11061 -Vernier type 7136 -Five spring (two open and two T1543 -43 -plate vernier .001 Mfd. withknob C. H. Rheostat $1.40 closed circuits, commonly called "two knob and dial 4.35 former $3.75 circuit filament control"). Each .88 The unshielded types listed be- 11062-C. H. Rheo- 7132 -Plug, telephone type with short INDUCTANCE COIL MOUNTINGS low have terminals mounted on stat without vernier. .95 twirled grip .35 For base or panel mount- Bakelite panel. Two ratios. T137-Plug (as shown), cord tips fit into ing. Connecting leads 11510-Transformer, 10 to 1 ratio $3.55 71064-110 card vernier rheostat operates plug 1.05 furnished, coil settings 11503 -Transformer, 3 to 1 ratio 3.50 train one knob $1.48 7139 -Plug with threaded barrel instead are adjustable by means RADIO FREQUENCY T1065 -Howard rheostat without vernier 1.00 of set screw. Takes cord tips .55 of knobs. Made entirely of bakelite with nickeled AMPLIFYING TRANSFORMERS DIALS VARIABLE brass metal parts. Coil Radio frequency transformer cir- Genuine Bakelite position can be locked cuits help to eliminate static and Dial as pictured. GRID LEAK by knurled set screws. interference, thus permitting easy, Sharply engraved T1603 -Three coil mounting sharp tuning of long distance sta- Pencil mark type. Removable $3.50 Enclosed in metal case for divisions a n d black enameled cap. T1602 -Two coil mounting tions. figures filled 11601-Single coil mounting .50 shielding and can be mounted in T50 -Grid Leak 20e tube socket if desired. Wiring with a brilliant INDUCTANCE COILS diagrams furnished with each Bakelite white. Three-inch Composition wound, nicely fin- diameter, with bushing for 3/16 -in. or GRID Rigidly transformer. Each AND PHONE CONDENSERS ished, low distributed capac- 11500-Transformer. Each $3.47 shaft. Set screws included Doz. Mounting holes spaced to fit ity. All coils are equipped 1500 -Dial 55e 56.40 screws of above Grid Leak. Mica with standard mountings. "B" BATTERIES Three-inch moulded composition dial as pic- insulation, wrapped with var- We can supply any of these Standard high grade radio tured. Has a luster that cannot be told from nished cambric tape. Capacity. coils without mounting plugs. "B" batteries. Never over Bakelite. Set screws included. Each Doz. 00025 Mfd. for 55c less than the prices five days old. T550 -Dial, 3 -16 -in. Shaft 28e $2.75 -in. Shaft 28e 2.75 T55 -Grid Condensers 15e shown. The wave lengths shown are range 1230-22% v o l t Signal T555 -Dial, r/ T59 -Phone Condenser .001 Mfd 20c limits, based on a variable condenser of .001 Corps type. Size 3%x2 x Mfd. capacity. 2% inc:i $1.08 CABINETS LOOSE COUPLER AND Number of Wave Price, 1235-22% volt U. S. These are reasonably TUNING Turns Lengths Mtd. vy Po priced but sturdily COIL 125- 250 $0.95 taps. Size, 5x3x2 vahe$1.80 built cabinets of weath- 11725 25 Priceble-5 This loose 175- 450 0.98 T240-22% volt larch. variable-5 posi- ered oak. The top is coupler is 71726 35 removable loosening Pre- 11727 50 240- 720 1.05 tive taps. Size, 6%14x3. Price 2.25 by ferred by many 1.10 T245-45 volt large size. Leads only. Size four screws. End posts because of its T1729 100 500- 1450 1.14 13x4x3. Price 4.00 are routed to take wide range - 900- 2500 1.28 panel 3/16 -in. thick. 200 11731 200 BINDING POSTS to 3500 11732 250 1200- 3500 1.36 The panels are not In- Complete with screw and washer. i lengths. meters. Ma- 71733 300 1500- 4500 1.38 An cluded. See table for panel hogany finish. 1.65 brass finished in polished nickel or T212 -Can be user, for detector and two T1735 500 2800- 6100 with black composition as All metal T1737 750 5000-12000 1.95 top listed Panel space, 5%x12 $2.50 Parts are brass, Order by number. 1214 be used for 2 variometers and 12 T1738 1000 7000-15000 2.30 -Can nickeled and highly buffed. Secondary has Each Doz. 1 coupler. Panel space, 5%x14 2.75 coil head. 11739 1250 9750-19500 2.55 point switch mounted on Bakelite 14500-26500 2.70 T110-Large size, all nick- 1218 -Can be used for 2 variouneters, 1 Windings are green silk -covered wire. 11740 1500 eled 10e 950 coupler and detector. Panel apace, %x18 3.00 T800 -Size, 51/2x8x18 inch $6.50 STORAGE "A" TI22-Medium size, nick- T222-Can be used for 2 variometers, 1 T805 -Two Slide Tuning Coil 2.60 BATTERIES eled, with hole for phone tip or wire 4e 35e coupler, detector and 2 step. Panel 7112 -Medium size, black compo- apace, 5%x22 3 25 CRYSTAL DETECTOR Built of entirety new parts. sition top 5e 48e PANELS A very high grade With the proper care they 1120 -Large size, composition top 8c 85e glass should last several years. Genuine Formica. Panels to fit our cabinets. enclosed crystal de- has rub- 51/2x12 -in. 3/16 -in. thick.$1.38 111 tector including the The De Luxe type SWITCH POINTS & STOPS T262 -Panel, crystal. All metal parta ber case and cover for top as 1264 -Panel, 51/2x14 -in. 3/16 -in, thick. 1.64 pictured, the Standard type Brass, polished nickel finish. T268 -Panel, 5%x18 -in. 3/16 -in, thick. 2.08 nickel plated. Adjust- Screw -in. 2.53 able to any point on the has black wood case similar size, 6/32x% ins, long, two nuts with T272 -Panel, 5%x22 -in. 3/16 thick. to ordinary automobile type. each contact point and one with the crystal. to full SPAGHETTI AND WIRE WIWSWWtr T20 crystal Guaranteed give stops. Stops high enough for any wiring. Yellow finish spaghetti. -Enclosed rated capacity. All 6 volt of lever and For cabinet detector $1.30 type point. 133 -Per 4 -ft. length 27e but nicely constructed de- batteries. 1130-Switch Point Hun - T32 Copper No. 16 Wire. ... Ft 2e A lover priced Amp. diem., % inch; height, Each Doz. died -Tinned tector. Crystal included. Hour Shpg. 20 Ft. 30c T30 .88 3-16 Inch 3e 20e $1.40 T33 with insulation similar to spa- -Detector Number Rating Wet. Price T150 -Switch Stops 3e 20e 1.40 -Wire 60 40 $15.50 ghetti on it. Wire is tinned for soldering. TO 60 -De Luxe 10 feet 37c TESTED CRYSTALS TD 80 -De Luxe 80 50 17.50 SWITCH LEVERS Price 20.50 nickel - or TD100-De Luxe 100 62 A high grade, polished INSULATORS Selected and tested galena TS '60 -Standard 60 35 12.25 plated lever with solid moulded These are very strong strain silicon. Each box contains 14.25 black composition knob. Com- four to six ordi- T8 80 -Standard 80 90 type insulators. Each Doz. enough for 78100 -Standard 100 50 16.25 plete with panel bushing. T360 -Moulded Insulator shown nary crystals. TSII0-Standard 120 60 18.25 Each Doz. above $ .10 $1.10 712 -Galena, Per pkg..$0.12 items T151-1- in. Radius 18e .12 The above storage batteries are the only $2.10 1365 -Porcelain insulators .09 .95 T13 -Silicon. per pkg.. on which we do not nay transportation charges. T152-1i/a-in. Radius I8e 2.10 We will ship by Express. Collect. TI55-1?z-in. Radius (8e 2.10 ANTENNA WIRE LIGHTNING ARRES- The following are 100 -ft coils of 7 strand TER OR PROTECTOR cable of No. 22 wire, which makes the best Mounts indoors. Porcelain HOW TO ORDER Aerial. Use phosphor bronze, where the base, nickeled cover. Listed Order from this page. Please give number description and price of the articles you span is 100 feet or more. It is stronger. by the Underwriters' Lab- order to help us avoid mistakes. Total the amount of your order and send Post Office T350 -Stranded Phosphor Bronze, 100 ft. $1.47 oratories under April, 1922, money order, certified check or draft with your order. Be sure to give your name and T355 -Stranded Copper, 100 ft. .77 regulations. street address on both letter and envelope. Do not include money for transportation. We T356 -Single No. 1l here solid Copper T300 -Protector $1.40 i pay it except on storage "A" batteries. See ads of previous months for other items. R'irc. 100 ft .42 1124 JACKSON BOULEVARD GREAT LAKES RADIO CO., CHICAGO, ILL, 1096 Science and Invention for .1Tarch, 1923

POSITION SALARY - AUTOMOBILE RefrigeTatkon ehe Nome ENGINEER $125wtra By L. K. WRIGHT REPAIR MAN $5O WEFAI CHAUFFEUR $40 Wä (Continued front page 1075) Put Your Name The flywheel side of the shaft offers the ters a density of 90°. The density of this ON hardest problem, for the old hearing must solution is about 23° Baumé, its weight THIS be removed and the opening drilled an inch about 13.5 pounds per gallon, and the freez- Pay -Roll larger to take the new bushing. This new ing point -9° Fahr. In order to keep the Men like you are wanted for big -pay posi- bushing will be two inches longer and fitted brine from congealing or weakening test tions in the fascinating field of automobile with a cap to give pressure on the packing. periodically and keep to standard density. engineering. We have The illustration, A, explains it. Because of In placing the brine tank in the ice bunker made it easy for you to the length of the new bearing the idler set it up on pieces of wood (2" x 2'"), spac- fit yourself for one of Price pulley will have to be removed and the ing on all these positions. You don't sides to allow for air circulation, have to go to school. driven pulley moved out to provide clear- for it is upon this that the efficiency of the You don't have to serve Reduced ance. The projecting bit of shaft may he plant depends. an apprenticeship. Fif- Down goes the price sawed off to give a finished appearance. It All valves, nipple and fittings are /-inch teen automobile engi- on these famous Auto is a good plan to drill an oil shaft in the neers and specialists Books. We have extra heavy galvanized iron or brass. De- have compiled a spare induced our printers new bearing at an angle, as shown in sketch, termine the suction side of the compressor time reading course that and binders to cut to insure proper lubrication. It is best to will equip you to be an the price they charge and insert a short nipple. It may be neces- automobile expert with- us. We pass this sav- pack the stuffing box with flax cord that sary to hush down to receive the nipple, out taking any time from ing on to our cus- has been soaked in graphite and glycerine. to which is coupled a cross fitting, No. 6, present tomers. Your work. Another packing, though not so good, is the upper opening of which supports a low butchers' white meat string soaked in a Mail Coupon Now pressure gauge (reading to 100 lbs.) ; the AUTO thick mixture of graphite and glycerine. under opening has a 6 -inch nipple with a For FREE Trial Next remove the oil filler from the crank- pair of flanges at its lower end. The lower BOOKS case and set an angle valve, No. 10, in its flange will have several uses and a plug and 6 Volumes Shipped Free Partial List place. The lubricant used in the crankcase nipple should be kept ready. The other of Contents is glycerine, and is poured with a funnel opening of the Now ready for you - cross fitting is connected by an up-to-the-minute six - More than 190 Blue through valve No. 10. Upon the opposite nipple to a shut-off valve, No. 3. This volume library on Auto- prints of Wiring side a glass gauge should be fitted by drill- valve is connected to the suction line of mobile Engineering, cov- Diagrams ering the construction, Explosion Motors ing and tapping two holes in the crankcase, copper tubing by means of a reducing tub- care and repair of pleas- Welding as shown in B. ing connector, or a bushing and a connector, ure cars, motor trucks Motor Construction No. 8. Be sure that this suction line is and motorcycles. Brim- and Repair Any other vents or openings in the crank- the ming over with advanced Carburetors and case must be plugged or covered by screw- one that leads to the top of the coil in the information on Lighting Settings ing pieces of sheet metal over them. Al- brine tank. The discharge side is coupled Systems, Garage Design Valves, Cooling to the compressor by and Equipment, Welding Lubrication ways gasket any opening so covered. Also means of a short and other repair methods. Fly -Wheels be sure that there is a good gasket be- nipple, to which the cross fitting, No. 5, is Contains everything that Clutch fitted, the top opening Transmission tween the sections of the compressor. supporting a high a mechanic or an engi- pressure gauge (H.P. to 100 neer or motorcyclist or Final Drive A condenser is lb.) the bottom Steering Frames constructed by making a opening being fitted with a nipple, the owner or prospective helical coil containing about seventy feet six inches owner of a motor car Tires of long, capped at the bottom; or a coupling ought to know. Written Vulcanizing quarter -inch copper tubing. One end of this Ignition may be used in its place, being fitted with in simple language that coil is connected to a small receiver tank, C, anybody can understand. Starting and Light- a purge cock. This acts as an oil inter- Tastefully bound in ing Systems made of a two-inch piece of extra heavy ceptor Shop Kinks and removes all lubricant (glycerine) American Morocco, flex- galvanized pipe, eight inches long and capped which escapes past the piston ible covers, gold stamp- Commercial G at both ends. These caps are drilled and rings and ed, 2,630 pages and 2,100 Design and Equip - prevents it from entering the system. Oil ill illustrations, tables and meat tapped to take the tubing connectors by the lines is detrimental explanatory diagrams. Electrics which the tubing is to refrigeration. Storage Batteries secured to the tank. As This purge should he A library that cost thou- shown ill drained occasionally. sands of dollars to com- Cars and Repair the sketch the receiver is lying The other trap, on fitting Motorcycles down. but it may placed No. 6, is for the pile but that comes to be in an upright purpose of trapping any scale and preventing you free for 7 days' ex- Commercial Trucks position in the center of the coil if is amination. Glossary care it from getting into the compressor, where taken to see that the outlet line supplying it might do damage the expansion valve to the piston and com- is at the bottom. The pressor walls. After one or two Only l0c a Day coil and receiver are then set into a tank cleanings Not a cent to pay in advance. First you eel the books all the scale will be removed from the In your own home or shop. Just mail coupon and pay constructed of galvanized iron, which has system. Valves, numbers 1 and 2, express charges when books arrive. You can read them an inlet and an outlet line for water. The are stop and study them for seven whole days before you decide valves. Number 4 is a check valve that pre- whether you want to keep them or not. If you like the inlet water line should be at or near the vents the books send only $2.80 in seven days and $8 a month until bottom high pressure side backing the special introductory price of $21.80 has been paid. and the outlet line near the top. through the compressor (Regular price $45.) A cover to the low or ex- is provided through which the pansion side. The needle copper tubing projects. After carefully valve, No. 7, is Send No Money Now spaced from the stop valve with a short soldering the cover to the tank, and the nipple. In Don't take our openings connecting tubing to the valves word it. about the copper tubes, test with use tubing connectors, for See water pressure and as at Nos. 8, 9, etc. the books see that it is tight. If it is desired a pair of flanges without cost. After may be There is so ascertaining your electric circuit placed between the stop valve (No. 2) and much profit in factors, purchase a suitable motor of one- the expansion (needle) valve and a disc of this offer for half horsepower. Measure the size of fine screening you. that we the inserted ill the flanges to inter- urge you to pulley on the compressor and note the speed cept any dirt which would interfere with waste not a of the motor to determine the size of the the proper action of the needle valve. If moment in drive pulley. The compressor should run the expansion sending f o r valve is suspected of being the books. Put from 150 to 250 R. P. M. The motor, com- clogged, mark the position of the wheel the coupon in pressor and tank are preferably bolted to a with a piece of chalk and open fully, count- the mails to-. common base ing day. Send no constructed of one -inch pine, the number of turns, then return to money-just for if the parts are not rigidly fastened, exact position for the particles of dirt will the coupon! there is a tendency to draw together. If have been forced through and away from American Technical Society, Dept. A-253 Chicago, Ill. the motor is equipped with a belt tightener the needle. Figure D shows how flange it be may would be the better policy to use an end- installed. In fitting all joints use a paste less belt, because AMERICAN TECHNICAL SOCIETY it is the more silent. made of glycerine and litharge. Use but Dept. A-253. Chicago, III. A measurement is taken of the ice bunker little glycerine and mix with the finger Please send me the 6 -volume set, "Automobile Engi- and a tips to insure neering," for 7 days' examination, shipping charges col- galvanized tank of suitable size con- a smooth, syrupy mass with- lect. If I decide to buy, I will send $2.80 within structed. A coil of sixty or more feet of out lumps. Mix but what is needed for 7 days and the balance at $3 a month until the one -quarter inch copper tubing is fitted immediate $21.80 has been paid. Then you send me a receipt into use, as it will harden and be showing that the $45.00 set of books are mine and the tank, which is then filled with brine. It useless in a few minutes. Do not get any fully paid for. If I think I can get along eithout is better to provide the tank with a loose- the books after the seven days' trial, I will return of this sealing compound inside the fittings, them fitting cover as the sweat from the unsub- at your expense. To insure prompt shipment fill apply to the threads of the nipples only and nut all lines. merged lines would, in time, cause it to never in valves or sittings. overflow ; it would also Name weaken the brine. Before attempting Dissolve three to five pounds of calcium to charge the machine a high pressure test Address chloride, depending upon the purity in each should be made. This Employed by gallon of water, until the hydrometer regís- (Continued ou page 1098) 1097 Science and for AUarch, 1923 RADIO BARGAINS Buying Direct -in Quantities -for Cash, and operating on a "SMALL PROFIT-BIG SALE -QUICK TURN" basis, MAKES POSSIBLE THESE VALUES RADIO SUPPLIES PURCHASED HERE ARE SOLI) UNDER A POSITIVE GUARANTEE OF SAT'ISFACT'ION. WE CARRY THE LARGEST NEW STOCK OF FIRST QUALITY NEW MERCHANDISE GE$U NE MA COMPLETE PARTS FOR y ARIOMETER5 VALUE,HNOW Y $1.95 REINARTZ CIRCUIT VARIOCOUPLERS $4v500WVALUE $1.75 Includes 1 7x18 Formica Panel, 1 Bakelite 23 HONEYCOMB COILS Socket, 1 Howard Vernier Rheostat, 1,500 Turns $1.50 150 Turns 60c 3 1,250 Turns 1.50 100 Turns 50e Plate Condenser, 11 Plate Condenser, 1,000 Turns 1.25 75 Turns 40e Points, 750 Turns 1.00 50 Turns 40e Switch Levers, 2 Dozen Switch 250 Turns 75c 35 and 25 Turns 40c 1 Reinartz Wound Coil, 1 Variable Grid Leak, 8 Binding Posts, 25 Feet Tinned Wire, $8.50 Guaranteed 3,000 Ohm $3.65 1 Base for Coil, 1. Mounting Base Board, and 1 Diagram to Con_ 1 1 HEADPHONES struct This Set. $ ,45 RHEOSTATS 45c Complete Sponge Rubber EAR CAPS, Pair 50c ( ORIPE "GINAL BALDWIN UNITS... .$4.951 TYC' DIALS, 2, 3 and 31/2 in. 25c COMPLETE PARTS FOR KNOCKDOWN RECEIVING SETS Thordarson Amplifying TRANSFORMERS 1 Rheostat, This includes 2 Variometers, 1 Coupler, 3 Dials, $4.50 Value, Now $2.95 1 Socket, 1 Mahogany 1 Cunningham Detector Tube, Bakelite Formica Panel, 6 Binding Posts, 1 Switch Cabinet, 7x18 s set. 12 Switch Points, 2 Stops and 1 Diagram to GREWOL DETECTORS $1.45 Set is capable of receiving 1,000 miles if installed with outdoor aerial 17 Signal Corps Super Sensitive Microphone VARIABLE CONDENSERS $2.45 $4.30 Value, 43 PLATE, now $1.75 Transmitters $3.70 Value, 23 PLATE, now $1.45 11 PLATE, now $1.35 for $3.30 Value, $1.25 Solid Copper Airial Phone Caps $ ,2G' $3.10 Value, 5 PLATE, now Wire, 100 mostly all phones now $1.15 ft.... $ .35 J $2.70 Value, 3 PLATE, Spaghetti Tubing, Signal Corps Hot Type 194-W', Yard .10 Wire Ammeters at 5.45 U. S. A. Signal Corps.Aviation Cord Tip Anti -Capacity Electric Phones $7.95 Plugs .60 Switches 1.50 Western Lightning Lightning Each Phone Cap is covered with large soft rubber ear cushions,) Arresters .95 2.65 and an aviation leather helmet goes with each set! These are Switches the only phones to pass the Government specifications for sensi- 2 -Slide Tuning Coils Hydrometers, for in aircraft at 1.95 tiveness and loudness, the requirements called now at .45 reception. 3 - Coil Honeycomb Mount - ings. Freshman Variable .95 Complete Parts for Flewelling Circuit With knobs.. 4.20 Grid Leaks 'Includes 6x14 Formica Panel, 23 Plate Condenser, 3 Micon Grid Leak, 1 Remler .006 Condensers, 1 Freshman Variable SWITCH LEVERS 20c Leak, 2 Coil Mount, 2 Honeycomb Coils, 2 Cail Plugs, 2 Binding Posts and 1 Socket, 1 Howard Vernier Rheostat, Construct This Set. Q` 1 Diagram to Wire and 12/ BINDING POSTS, per doz. 50c Complete a -r v in. thick, 1 1/2 c MAGNAVOX Loud Speaker, FORMICA PANEL, 1/8 Black or Brown ... . Type R3 $3495 Square Inch,

We Guarantee All Merchandise Purchased of Us Charges Mail Orders Receive Immediate Attention and We Pay Transportation Chicago Salvage Stock Store 511 SOUTH STATE ST. CHICAGO, ILL. Science and Invention for March. 1q23

ReSirIlgeTnüion the 11 lome (Continued from page 1096) is accomplished by closing valve No. 3 sure gauge begin to "spin" (mount tightly, too all other valves being open ; be rapidly) stop the machine immediately sure as that the expansion valve is fully opened. there is too much refrigerant in the plant See that the motor cups are filled with oil giving a hydraulic pressure which might or grease, the crankcase showing at least strain the outfit. a half gauge of glycerine, the belt tight, To run the plant have all the ; and that water is flowing through the con- valves open denser see that water is passing through the con- and that same does not leak. Re- denser move the flange and then start machine. The needle from scale trap (No. 6) valve works on and start machine, running high pressure a micrometer screw and is gauge very sensitive, a mere touch being sufficient up to 100 pounds. Then stop machine to make and replace the flange half, a difference of several pounds' pres- meanwhile fitted sure on the low side. This with a plug. This plug is but temporary, valve will have HIGH SCHOOL but nevertheless, to be adjusted so that the low pressure should he tight. Be sure gauge carries and use gasket between from five to ten pounds of the flange halves gas pressure, while the high pressure and when thought tight, open up valve No. 3. gauge COURSE will read from thirty to eighty pounds. IN This will give an air pressure on the Pressures whole system. The pressure on the high (liquid) side will will fall to about depend upon the temperature 80 pounds or less and then should remain of the cooling TWO YEARS at a constant. water, and pressures on the low side will Look over all joints for leaks ; have to bad ones can be immediately be adjusted, so that the return or detected by suction line frosts up to, the hissing ; but not on the YOU ARE BADLY if you lack sound if in doubt, test with compressor. soap and water and watch for HANDICAPPED High School bubbles. If training. When satisfied that the system is tight, the trial run is satisfactory begin to You cannot attain business or social open the purge cock on the cross fitting remove charging hose as follows: Close prominence. You are barred from No. 5, and allow the air to escape. Then valve No. 3 and run machine until low pressure gauge a successful business career, from with valve Nb. 1 tightly closed, start ma- shows a vacuum, then close valve No. 1, the leading professions, from well - chine, exhausting the air from the system and disconnect drum by re- paid civil service jobs, from teaching through the purge. A good test moving lower flange. Insert a plug in flange to ascer- and replace and college entrance. In fact, em- tain whether the system is tight or not is to with leaden gasket or shellacked ployers of practically all worth -while fasten a rubber hose to the purge cock paper one. Then exhaust air and gas from positions and the compressor demand High School train- submerge in a pail of water. This also through purge. When all ing. You can't hope to succeed in shows when all the air is exhausted. When exhausted close purge tightly, make sure the face of this handicap. flange is tight, But you so exhausted, close valve No. 3 while the then open valves No. 1 and can remove it. Let the American machine is running. Then No. 3, and plant is ready to run. School help you. stop machine and unbolt the lower flange, take out the The best location for the plant is right FIT plug and insert a nipple to which a charging next to the ice box, or it may be located YOURSELF FOR A hose has been clamped. A charging hose directly under it in the basement and the BIG FUTURE This is made from a length of pressure or rub- lines carried through the ceiling. The re- course, ber tubing, such turn line can which has been prepared by some of as is used by confectioners he insulated and prevented on their carbonic lines. A from dripping (caused America's leading professors, will nipple is fitted by melting frost) by into the tubing and secured by three or four wrapping a layer of newspaper some two or broaden your mind, and make you hose three inches keen, clamps. The other end of the hose thick round the line; then sew- alert and capable. It is com- is similarly equipped with ing on a canvas covering plete, nipple and clamps. which is finished simplified and up-to-date. It Most refrigerants are dangerous and waterproofed with a heavy covers all to use coat of as- subjects given in a resident and require special precautions, but the phaltum paint. Fasten both high and low school and meets all requirements of refrigerant used in this plant is practically pressure lines rigidly by means of hangers a High School training. From the odorless, non -injurious, non -explosive, and of strap iron, staples or wire. first lesson non-poisonous, yet to the last you are care- is efficient and best for The brine tank will take quite a while to fully examined and coached. household use. The refrigerant, ethyl chlo- cool down on the first run, ride, but once cooled is obtained in a steel drum, to which will retain its temperature for long periods the other end of the and take USE SPARE TINE ONLY charging hose is fitted but a short time to further cool. by means of the nipple. When the drum is In mixing brine it is advisable Most people idle hooked to do so a away fifty hours a up to the machine lay it on or sus- few days in advance in order week. pend to allow it Probably you do. Use only it from a scale so that the amount of to lose the heat generated in mixing. one -fifth of your wasted refrigerant entering the hours for system can be noted. If the builder places his plant study and you can With the drum in position and in an ex- remove your hose con- posed place it will be necessary to install present handicap within nected, start machine and exhaust the air water a two years. drain at the lowest point to drain the You will enjoy the lessons and from the hose and compressor. Close purge water and prevent the valve while machine freezing. The bearing on knowledge you will gain will well is running, and then the compressor may heat up open valve No. 1; then slowly slightly on the repay the time spent in study. open valve first run; the cap should be on chemical drum. Watch high pressure give adjusted to sufficient pressure to prevent escape of Check and mail the coupon NOW gauge very closely and load machine with gas and yet not about two pounds so tight as to heat the bear- for full particulars and Free Bulletin. of refrigerant, and then ing. If desired a safety give it a trial run. The pop -valve may be drum of ethyl installed by using a tee as per sketch American chloride need not be disconnected for the unload E to School at 125 pounds into a five -gallon can Dept. H-326 trial run; all that is necessary is to make of water. But because. sure the of the small amount Drexel Ave. and 58th St., Chicago valve on the drum is closed. In of refrigerant and its harmless charging the machine should nature, this MME »I the high pres- is not absolutely necessary. American School Dept. 11-326 Drexel Ave. 67.. 58th St., Chicago II tow EnameUed Ha-on Tubs Send me full information on the subject checked Are Ma l e and how you will help me win success. By H. WINFIELD SECOR Architect ...... Lawyer Building Contractor Machine Shop Practice (Continued Automobile Engineer Photoplay Writer from page 1066) Automobile Repairman - Mechanical Engineer Civil Engineer Shop Superintendent he removes the tub from the oven. If it now removed, placed Structural Engineer Employment Manager is hot enough, on an iron truck and Business Manager Steam Engineer the second operator shakes wheeled off and allowed Cert. Public Accountant Foremanship the powder to cool. Accountant -like enameling mixture over the Fig. 5 shows red and Auditor Sanitary Engineer inside of the hot tub removed from Bookkeeper Surveyor (& Mapping) tub and the top of the rim, this oven momentarily, while Draftsman and Designer Telephone Engineer mixture being a secret formula second operator Electrical Engineer Telegraph Engineer with each shakes enamel powder over Electric Light & manufacturer; the tub, while Power High School Graduate after this the door is quickly Fig. 6 shows the tub being General Education Fire Insurance Expert opened by applying compressed replaced in the Vocational Guidance Wireless Radio air to the oven, in order to fuse and bake the Business Law Undecided control cylinder, as before described, and enamel. After the tubs have been carefully in- the tub is replaced in the oven for a few spected for flaws in the enamel, Name minutes. The intense they receive heat causes the enamel a coat of red -lead paint over the mixture to melt and fuse together, and ad- face outer sur- Address to prevent rusting, and they are then here to the clean iron surface over the in- placed in the storage rooms, side of ready for ship- the tub and the rim. The tub is ment to all parts of the world. Science and Invention for March, 1923 Rapid Scerme es gll Chand pp a a íf ®henFtl1es liii£t'CflsIleit' Technical Training By JOSEPH H. KRAUS (Continued from page 1051) Will Double Your Income side wall. Consequently, the actor appear- ing on the upper deck of the structure will seem to describe an arc as he turns and walks away. The structure of the plat- Send for the Proof the audience, due forms is at no time seen by There is no quicker, surer way for a man to to the fact that only the characters or the are get out of a rut and rise to high pay than particular scenes which are to be shown, through technical training. Never before such illuminated. Meanwhile other black robed of the a pressing need for experts in every line of figures are pushing one or the other in building enter- scelles productive industry and platforms into place or erecting other prises. If you are in a small pay job-if you so that the moment the lights go out on future," mail the coupon for be turned on "can't see the one of the stagelets, they may information on where the opportunities are at another place, and the action continued Of and how you can prepare for them. there without a moment's intermission. a Free Trial Lesson if you are in- the is not We send course the full size of stage terested in Drafting or Plan Reading. Free used at all times. Sometimes one or two, if your inquiry is arc Books and Blue Prints or even three of the smaller scenes, about training in the Building Trades. simultaneously illuminated. These are not all on a level with the stage floor, but ar- ranged in tiers, as our illustration clearly Plan Reading shows. In addition to the platforms already mentioned, there are on either side of the Estimatingnildin stage two more small stages also .on rollers. Drafting, B Superintending One of these contains the permanent set- g ting of the interior of a room in which Training Easily Kreisler is telling the story ; the other is so and Other Specialized arranged that the scenes thereon can be changed. When any of the stages are not Obtained in Spare Time at Home being employed, they are covered by black Make your spare time count for more money. kiíig curtains. Put in a few hours a week to get specialized knowl- IIt'Inw, MM15.5 In the full stage utilizations, each of the edge on any of the subjects listed in the coupon six sub -stages may have various scenes and your future is secure-you step years ahead of then by placing the plodder who is "waiting for his chance." With É .k- mounted upon them, and technical training you need not wait for opportun- ill the correct position, the entire stage N. them ity. You will be the man wanted to plan or direct setting is built up. important work. You will be in line for high When Kreisler floats through the air he Designer salaries and important positions. Auto Expert is standing in a box, (erected on the mov- ing bridge platform), and- seems to float Get Practical Instruction From idly through the air landing on the stage Chicago "Tech" Experts beside Donna Anna. As a matter of fact, has stepped from the box to the Enrolled with Chicago "Tech" you are instructed Kreisler by practical men. You are taught the way things top of a platform made of structural steel, are actually done in big engineering or building resembling a pair of parallel rules. A cable enterprises. That is why Chicago "Tech" men are a hold it in place, an operator re- certain way to and winch Plant Supt. so constantly in demand. No more Building Supt. leasing the cable gradually, permits Kreisler success than to get this kind of training. And now to descend through the air to the stage. is the time to get it when there is such a pressing Kreisler may act at all times while on this demand for experts. No special preparation re- his position being perfectly secure. quired for these courses. They are easy to under- platform, stand -every point is made clear, and at every step A spot -light illuminates his face only. you have practical men directing your study. In another scene where Kreisler cuts the heads from his enemies with his baton, three Chicago "Tech" Men Succeed dummies are employed, the heads of each of in Everywhere you find Chicago "Tech" men Aero Expert the enemies arc held over the collar band Plumber paying jobs or in paying businesses of their own. of the dummy. The arms of an assistant J. A. Da Costa was a punch R. L. Cary was a drafts- enter the arms of the dummy, and the arms press hand who enrolled with man-took Chicago "Tech" Chicago -'Tech" and as a instruction and became Chief of a second assistant enter the legs. In result of his training was made Draftsman and Supt. of Con- manner grotesque dances are produced Production Manager. struction at 4 times former this A. S. Ross took the Draft- salary. by the two assistants operating the arms and ing Course. Salary was O. L. Rosin became a pros- raised $225 a month. Now in perous architect and con- legs. The head when cut off moves to a profitable contracting busi- tractor as a result of his Chi- side, separating itself rom the body coin- ness. cago "Tech" training. pletely. A slit in the black cloth background Hundreds of other men send similar reports of Contractor hides the actor's body. Spot -lights follow Shop Supt. success asia result of_their Chicago "Tech" training. up the movements of the heads. of Send the Coupon-Today An Unsuspected Function No matter what your present job or College you can get it by mail. Find out Sugar where you live, you can get this pay about the Chicago "Tech" Method now. raising technical training from the Chicago Mark X in the coupon to show which By C. L. MELLER "Tech" experts. If you can't come to the course interests you and mail it today. (Continued from page 1073) emt riNo ml mug MMI as,r..a_MI.e_ I» lam CHICAGO TECHNICAL COLLEGE, enduring sub -zero temperatures. In contrast 345 Chicago Tech. Bldg., Chicago, Illinois I have to this clear sap,, that will boil down to prac- Without cost or obligation to me please send instructive matter about opportunities in line tically nothing more than sugar, there is the marled with "N." sap of many another genus of trees which ni Drafting (The Big salary )'ourse) ¡ Aeronautic Engineering even to the touch shows a sticky viscosity and no experience necessary L.J All about aeroplanes boiled a or less mucilag- I--1 Building Trade Course n Plumbing, Beating and down produces more LJ Ventilating inous substance. Rubber is the best known for men in the building lines product of such a tree sap. Freezing a sap of Surveying Steam EL.1 and Map Drafting Engineering this latter type separates it into a number of Automobiles, Plan Reading for Shop Men- constituent parts, which seem unable to re- tins Engines, Starting, Lighting, ete. E )laehinists, Assemblymen, ele. combine after thawing, primarily because they were not in solution but were held in Name suspension; low temperature brings about a form of coagulation in a sap of this kind Address analagous to that brought about by boiling. Post Office State 1100 Science and Invention for pardi, 1923 Electrical Experts Recov ring Sunken Tneanures EARN (Continued from page 1056) keel, which is often not the case. In some to submerge it is pumped out, of these methods, but due to $12 holes are to he drilled the anchors, the pontoon raft is not per- to $30 a Day into the sides of the vessel, and expansion mitted rise bolts to to the surface of the water. to which the cables are attached, are Its buoyancy, being considerably greater inserted into the holes. Even in wooden than vessels the counter effect produced by the ves- such procedure presents many grave sel at the bottom, will cause the raft to difficulties, and the sides of sail vessels maintain its predetermined under the position with re- stress developed by the lifting lation to the surface of the water, even when pontoons or jacks, would tear out these steel the jacks are operated. plates as though they were shells of pecan Compressed air is now nuts. In forced into the the present installation a different projecting lugs around the vessel, and air method of raising a ship is employed. Here permitted to pass into the a framework cradles, making built of structural steel, to them likewise more buoyant and taking up meet the lifting stresses placed upon it when some of the stress, which would otherwise the sunken vessel is to be raised, is lowered fall upon the lifting cables. over The air forcing the vessel as she lies on the bottom of itself around the base of the vessel to he the sea. A globular diving bell housing raised, loosens the sand and an operator, agitates it. In What'sYOUR Future? who can communicate with the this manner the suction effect met with in surface pontoon, directing in this manner attempting to raise Trained by a vessel, is materially "Electrical Experts" are in great means 'of telephone or control switches the decreased. The lifting jacks are now oper- demand at the highest salaries, and the descent and positioning ated, portunities op- of the cradle lift- by opening the valves, permitting water for advancement and a big success in this line ing devices, are the greatest ever known. assists in the proper locationing under great pressure to thus enter of these the cylin- "Electrical Experts" can earn $70 to $200 cradles. The upper part of ders, slowly at first. Fit a week. the The result is that a yourself for one of these big paying positions- cradles are made buoyant, when filled with uniform lifting effort is developed, air, which BE AN "ELECTRICAL EXPERT'S so that they may be floated around, or increases and finally the weight of the ship the air may be withdrawn, to permit is over -balanced and Today even of a it rises until the pis- the ordinary electrician-the gradual descent. At the base of the cradle tons reach their extreme position. "screw driver" kind-is making money-big two steel projecting The money. lugs are to be found. jacks being automatic in their locking effect, But it's the trained man-the man who knows These are perforated, the whys and wherefores of Electricity-the "Electrical so as to allow air hold the vessel in the position to which it Expert"-who is picked out to "boss" ordinary electri- or water at a high pressure to be has been brought, cians-to boss the big jobs-the jobs that pay. driven and the action of the through these openings. The jet of pistons is reversed, the or air water under pres- $3,000 to $10,000 A YEAR water thus formed, clears away the sand sure being permitted to escape. This opera- at the base of the cradle and under the ves- tion is repeated until eventually Get in line for one of these "Big jobs." sel. Hydraulic the vessel pistons 'drive the lugs be- has reached its position within the cradle, by enrolling now for my easily -learned, neath the vessel. quickly grasped, right -up-to-the-minute, Spare -Time formed by the partially submerged Study Home - pontoon Course in Practical Electricity. In order to be assured of the fact that or raft structure. AGE OR LACK OF EXPERIENCE the cradle will not jam into the ribs of the When in this position, locks and chains vessel, cutting tools, found at the base of are swung around it and the anchors are NO DRAWBACK the cradle, and released by either cutting You driven by compressed air or the cables or rais- don't have to be a College man; you don't have water power ing them by means of to be a High School Graduate. My course in Electricity motors, clear away the silt at winches, which neces- is the most simple, thorough, and successful in existence the base, plowing a furrow as sitates further submergence of the pontoon and offers every man regardless of age, education, or they move ous previ- downward. structure, so that experience, the. chance to become, in a very short time, If a greater downward pressure one of the anchors may an "Electrical Expert," able to make from $70 to $200 is desired, be lifted at a time. a week. some of the air in the top tank The cradle containing of the cradle is replaced by water, decreas- the raised vessel is then permitted to come I GIVE YOU A REAL TRAINING ing its buoyancy in this manner, to the surface and either towed or under its and con- own As Chief Engineer of the Chicago Engineering sequently, increasing its pressure. steam, reaches port and a drydock. I know Works, It will exactly the kind of training a man needs to thus be The devices the beat positions get seen that the revolving cutting used for raising the vessel at the highest salaries. Hundreds of must of my students are now earning $3,500 to $10,000. Many wheels at the base will clear away any course be large enough to complete- are now successful ELECTRICAL extra CONTRACTORS. hard obstruction, while the water or air ly engirdle the ship at the bottom of the YOUR SUCCESS GUARANTEED under pressure takes care of the sand; thus sea, regardless of whether it is lying on its by its own weight the side or in an erect position. If necessary, so sure am I that you can learn electrir ity-so cradle will slip down sure am I the smoke stacks that after studying with me you can ,,et into around the vessel until deep enough, when and masts may be blown the "big money" class in electrical work, that I will the hydraulically off by dynamite, so as to make guarantee under Bond to return every single penny paid operated projections clos- room for me in tuition if, when you have finished my ing the base the massive automatic tongs. are Course, you of the cradle come into play. The inventor not satisfied it was the best investment you ever made. proposes All of tote cradles having been put into place also to control the lifting jacks FREE-ELECTRICAL and connected with the surface singly, so that the strain will not he upon all WORKING pontoon, of them OUTFIT-FREE which must be considerably larger than the at one time, and one at a time can vessel to be raised, be released while the others I give each the observer below the are being op- student a Splendid Outfit of Electrical surface erated. Tools, Materials and Measuring Instruments absolutely passes the signal up for operation FREE. With me you do practical work right at the start of the jacks. The cost of salvaging operations with -at home. You start right in after the first few lessons to WORK AT YOUR PROFESSION such a device, would, however, be in a prac- The pontoon device having extremely tical way. been securely great, but the sea contains enough treasure anchored at four or more points, is now to FREE RADIO COURSE made as permit the salvaging of ships which buoyant as possible. All the water would more An up-to-the-minute Course in wireless Telephony from than pay for the apparatus, even and Telegraphy the pontoons which heretofore tended given free with my great Electrical if but two or three vessels were Course-two Courses for the price of raised. particulars. one. Coupon brings GET STARTED NOW-MAIL COUPON The 5ubsnairIlne of Tom®r-reow I will send you a valuable book Become entitled "How to an Electrical Expert," and full particulars of my By GRASER SCHORNSTHEIMER free outfit if you will send this coupon now. L. L. COOKE, Chief Engineer, (Continued front page 1053) reported that they will practically Chicago Engineering Works have caliber anti-aircraft gun mounted double hulls and will he minutely sub -di- on the Dept. 23 2150 Lawrence after part of the conning tower, on the base. Ave. vided. Again, it has been rumored that The prime CHICAGO, U. S. A. these boats will have armament of the ships will be light deck and con- torpedoes. It is understood ning tower armor to protect them against that there will CHIEF be six 21 inch tubes carried in submerged ENGINEER COOKE depth charges and light shells. The new positions, Chicago Engineering Works large Japanese four in the bow and two in the submarines are also credited stern. Ten Dept. 23, 2150 Lawrence Ave., CHICAGO, ILL. with this feature. extra torpedoes will be carried making a total of sixteen. Dear Sir: You may send me entirely free and fully Another feature is really comfortable The wireless equipment prepaid, a copy will be of a most of your boot:, "How.. to Become an quarters for Electrical the officers and men. This advanced type. It will include both surface Expert," and particulars about your Home feature takes large proportions and submerged Study Courses in and when it is sending and receiving out- Electricity Radio. realized it fits. that was necessary to give the Submerged, the boats w ill he able to German submarine crews two weeks ashore receive almost as well as though they Name to 'every were three days afloat, due to the hard- on the surface, but their sending power will Address ships of this service. be limited to about 100 miles, it is said. .The ' gun' ' batter), will' consist of one 5 As the Naval Treaty, formulated inch,. 51. caliber gun mounted at the just forward Washington Arms Conference, forbids of 'the conning tower- and a single -3 inch, us 23 to build battle cruisers for a period of ten Science and Invention for 111a,rch, 1923 1101 years, it is important that these boats be suc- cessful, as the only two agencies for turn- ing an enemy's line in action, are the battle cruiser and the submarine. Not being per- For For Old, have the ideal type, we must turn Younô, mitted to to these submarines. With these boats as a basis, as a last word in modern submarine design, let us For A is Everbe'iy consider the next step. submarine wanted which will be able to go to sea to raid commerce. This vessel will have to stay at sea for long periods. First, such a vessel must have great size in order to carry the necessary engine power for high enough speed to pursue and cap- ture a normal merchant vessel. Then, it must have fuel enough to be independent of shore bases for a long period. It must have accommodations comfortable enough to re- lieve the strain of a nerve-racking cruise on its crew. Lastly, it must mount guns heavy enough to engage and defeat a destroyer and to properly engage a cruiser. This means a displacement of about 6,000 tons. It means great Diesel engines capable of developing around 18,000 horse- power to get a proper speed. It means the installation of the great electric drive to translate this power into speed and to charge the great storage batteries for submerged maneuvering. It means spacious quarters for officers and men, huge tanks for fuel oil and finally a large and well placed bat- tery. Speed in submerging and coming to the surface is of prime importance as it meas- ures the time in which the vessel can get into action. Therefore, let us say that the boat's main battery comprises four 6 inch Portable guns which are enclosed in two water- Remington tight turrets, into which the men can go while the submarine is coming to the sur- face. Modern destroyers have batteries sel- dom exceeding 4.7 inches and, therefore the Typewriter 6 inch gun should be capable of answering them, as it is of approximately the size car- ried by the cruiser of today. By way of spotting the hits of these guns is the universal machine for personal writing. and scouting for the submarine while it is demanded by the indi- resting on the surface, a small plane is entire- It has every quality ly requisite. A catapult might be mounted vidual user. on the fore turret to launch it. The plane could he of a very small knock-down type, Compact-fits in a case only four inches high. using little space aboard a crowded vessel. As wireless progresses it might be pos- can be used anywhere; on your sible to install the Telephot aboard the air- Convenient- plane. In this way the submarine com- lap, if you wish. mander would at all times have a picture of the sea far beyond the vision of his ob- Complete-with STANDARD KEYBOARD servation instruments. This idea as to the submarine of the fu- and other "big machine" conveniences. ture may seem to be far in advance of possibility. But even now, it has been re- It also resembles the big machines in effi- ported that the Japanese are building a test vessel closely approximating the one out- ciency, for don't forget it's a Remington- lined herein. In this story we have at- tempted to confine ourselves strictly to lines with every merit for which Remingtons are capable of the development of which we speak. famous. Sold by 2,500 dealers and Remington HoveIltie5 at branches everywhere. New YOT.A. Auto show Write for our illustrated "For You, (Continued from page 1064) Address Dept. 14 1111111111111111111.1.11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111114 For Everybody." only the vaporized gas gets into the cylin- ders, and the liquid fuel is held in the basin marked. 1, until the engine develops suf- REMINGTON TYPEWRITER COMPANY ficient heat to vaporize it. A whirling mo- New York tion is imparted to the gas being taken into 374 Broadway, the cylinders by the fan -shaped stationary deflector marked 2. This also aids in keep- Paragon Ribbons for Remington ing the liquid fuel in the basin 1. The Portable Typewriters. Made by bowl is heated by the exhaust and when us. 50 cents each. $5.00 a dozen the liquid fuel is vaporized it passes on into the cylinders and is consumed. Two windshield wipers are shown in Fig. 5 and 7. The former is actuated by an electric motor, which through a reversing gear and chain drive, pushes the cleaner back and forth across the entire upper section 1102 Science and Invention for March, 1923

of the windshield. The automatic revers- which keeps its points clean by means of a ing gear is located in the box just to the draught of air drawn through the plug, Harding left of the motor. In the latter, Fig. 7, the the action depending upon the suction of is in the wiper is actuated by the suction of the mo- the motor. This draught not only keeps tor. The two cups are connected to the in- the points clean, but at the same time drives White take or vacuum tank, whereupon their rub- away the burnt gases from the points, there- House-so ber ends are alternately drawn in and re- by rendering them ready to fire the next leased, thereby imparting, through a rack charge. is the En- gear, an oscillating movement to the wiper. Fig. 10 shows a little electrical heating cyclopedia The cleaner or wiper can be locked from the device installed in the intake pipe, which va- inside of the car so that it will not swing porizes the fuel instantaneously, thereby Americana when not wanted. providing easy starting of the motor even A novel air-cooled motor is shown in Fig. in the coldest weather. This device gen- 6, which makes use of the heat -radiating erates a heat of only 500'F, thereby insuring qualities of copper. In the insert in Fig. against premature explosion. as gasoline Because t h e 6 it will be seen that the copper is electric- and air mixture do not explode until heated Americana ally welded to the iron. The copper fins to at least 700°F. containsthe are made of a continuous strip of thin Ait automatic gasoline signal which de- sheet copper so bent vet), latest au- nLdmonston, \\'ash.,D.C. that when wrapped pends upon an air -tight gasoline tank is thoritative in- around the cylinder walls, the bases of the shown in Fig. 11. This is a whistle located formation in crimps are in contact with one another, thus upon the cap of the gasoline tank, which on the most recent events completely civilization - scientific, political, eco- surrounding the iron cylinder when the gasoline reaches a level of about walls with copper. Space is of course left gallon, sounds a warning by means nomic and every other subject of human for of the interest, and hence, is the only encyclo- the push rods, and for close coupling of partial vacuum created within the tank. pedia which could possibly meet the the cylinders. A powerful air turbine creates Obviously, it is necessary that the tank be needs of the Nation's Chief Executive. a constant draught of air around the mo- air -tight for the operation of this device tor, as indicated by the arrows in the dia- The super -wheel, so styled by its gram. inventor, The New Encyclopedia is illustrated in Fig. 12. The spokes of this In Fig. 8 is shown a device whereby the wheel are composed of heavy spiral springs, water from the radiator to the motor may thereby taking up a great amount of the AMERICANA be stopped until the motor warms up. It road shock. Inside of the shoe is a soft is inserted in the water pipe between the mo- rubber insert with a vulcanized exterior as 30 Handsome Volumes tor and radiator and after the water in the shown, under which lies an ordinary tube. hose from the 3 Bindings India Paper Size 71/4x101/4 motor to the thermostat When these inserts are used, the tube is reaches a temperature of 178°F, the ther- inflated to the usual pressure, but is pro- Contributions, Type, mostat automatically opens the valve and al- tected from punctures and blow -outs by the lows the water to circulate around the soft rubber insert. New Pictures, Map s motor. If, for any reason, the thermostat (Editor's note: The names and addresses It contains a concise history of the diaphragm should become punctured, a way of the companies supplying the above des- is provided World War ; Latest progress in wireless for automatic expansion of the cribed accessories, will be furnished upon telephony; Latest developments in aero- thermostat, thereby opening the valve. receipt of a stamped, self-addressed en- nautics; Latest statistics on finance, A novel spark plug is shown in Fig. 9. velope.) population, political divisions, etc., etc. 88,000 Subjects 4,000 Signed Articles ElecQrogtatic A.C. tc) LS)OCU C®nveueers 10,000 Pictures 24,000 Pages of Text 300 Color Plates Full Bibliographies By CLYDE J. FITCH Maps, Diagrams, Complete Gazetteer Statistical Tables Universal Information (Continued front page 1077) due to Authoritative-Comprehensive the resistance of the electrolyte in the unit and made as shown in figure 6. They A product of the world's highest experts in rectifiers, and to the current leakage through consist of a strip of iron and a strip every branch of information. Designed es- the rectifiers, as the oxide film is not a per- of aluminum, each by 6" long, which pecially for American readers, all American fect insulator. /" subjects being covered by American author- form the rectifier, and an aluminum plate ities and more thoroughly than has ever be- The aluminum and iron strips of the rec- which forms one side of the condenser of fore been accomplished in a great work of tifier are each %" by 6" long. The solu- which the solution is the other side-the reference. tion is made by dissolving sodium phos- oxide film acting as the dielectric. An alumi- The ideal and necessary reference phate in hot water, after which the solution num plate 6" by 24" will give a capacity of work for professional men, business is allowed to cool before using The sodium about 26 microfarads. This plate may be phosphate men and students may be obtained from any drug wound in a spiral as show in figure 6. No other Encyclopedia is more comprehen- store. The rectifier will stand from 150 to The converter shown in figure 3 will give sive in its scope, more satisfying in its treat- 175 volts ment of every subject, more invaluable as a without breaking down, and as the a D.C. voltage equal to three times the source of accurate information in the home, voltage across terminals A and B is 310, it maximum value of the A.C. voltage, ne- educational institution, office, public library. will be necessary to use two rectifiers in glecting losses. This converter is very sim- etc. No higher tribute could be paid to the series. The high value of this great work than its use in rectifiers may be matte up ple. When connected to a 110 volt A.C. cir- America's greatest educational institutions, similar to the rectifiers shown in the photo- cuit only three small electrolytic rectifiers libraries, etc., including graph. and two sets of paper telephone condensers Yale University New York Publie Library The condenser should have a capacity will be l la rvant University New York State Library of required. The D.C. voltage will be Princeton University California. Stale Library several microfarads. Four, two microfarad 3X155 or 465, and will be slightly pulsating, Columbia University Chicago Publie Library paper telephone condensers connected in but may be smoothed out or filtered Johns Hopkins University' Mass. State Library parallel by University of Illinois Williams College will be sufficient when the current means of a condenser and a shoke coil University of Virginia Wellesley College as l'nlverslty of Minnesota Dartmouth College withdrawn is small. shown in figure 4. l'niversity of Nebraska Detroit l'ubac Library The converter is to be con- University of Penna. Minneapolis Pub. Library Stanford University N. Y. State Teachers' nected to the alternating cur- Mass. Inst. of Technology College rent line in series Vassar College Smith college with a 110 U. S. Naval war College l'ittsb. l'arnegie Library volt lamp. At first the lamp Randolph -Macon College University of Missouri Syracuse University McGill University will light up brightly, and as Boston Public Library Lehigh 1-ulversity the rectifying film forms Iowa State Teachers' V. S. Mi litany Academy College Cornell I o in'rsity on the aluminum electrodes the lanip will gradually go out. Handsome Prospectus Free The converter shown in The coupon below brings you our handsome figure 2 .will give the illustrated prospectus of the Americana. very You are under no obligation whatever in saine D.C. voltage as that of sending for this. Clip and mail today. figure 1, and the action is identical. The only difference The Encyclopedia is that instead of using paper condensers advantage is taken AMERICAN of the electrostatic capacity of 7 the rectifier itself for storing ENCYCLOPEDIA AMERICANA CORPORATION, k up the charge. This type of 27 William Street, New York, N. Y. 11 Peoples Gas Building, Chicago, 111. converter is very cheaply con- Please send me free of charge descriptive u structed. The small rectifier literature of the AMERICANA. g Y is made similar to the recti- Name fiers in figure 1. The other s Address rectifier and electrolytic con- i S,I.I denser are combined in one Group of eight rectifier cells and transformer cabinet. 1103 Science and Invention for March, 1923 A glance at the diagram will show that one-half cycle of the alternating current wave will charge both sets of condensers in These books will help you parallel, to the maximum value of the A.C. voltage. The two sets of condensers then discharge through the external circuit, in series with each other and in series with make the next half cycle of the alternating current wave, so that the voltage at the D.C. ter- minals will be three times the maximum value of the A.C. voltage. more Figure 4 is substantially the same as fig- ure 3 except that electrolytic condensers are used in place of paper condensers. This converter requires one rectifier and con- denser made up according to figure 6, one money! condenser made up like figure 6 but without the aluminum strip, and two small rectifiers The choke coil and paper condenser smooth out the resulting pulsations, thus making EARN more and the D.C. voltage constant for use on power earn more. The amplifiers or radio telephone transmitting way to the big- sets. The design of the choke coil will be pay job is through taken up later. the Croft books. The circuit in figure 5 will give a D.C. They teach you elec- voltage of twice the maximum value of the tricity as practiced A.C. voltage. For use on a 110 volt line by experts and put this converter will require four electrolytic you in line for an ex- rectifiers and two sets of paper condensers pert's pay. Electrolytic condensers cannot be conveni- ently used on this circuit. One-half cycle of the A.C. wave charges the other set of con- The Croft Library of densers. The two sets of condensers dis- charge in series through the external cir- Electricity cuit, thus doubling the voltage. Practical Study Course and Reference Library wiring diagram of A Combination Home Figure 7 is a complete 8 volumes -3000 pages -2100 illustrations-flexible binding the converter shown in the photograph. This by the writer and. EVERYWHERE the Croft Library is acknowledged as the standard converter was constructed -the leader-in practical electrical training. In the Croft books used for amplifying radio broadcast pro- you will find complete, detailed and up-to-the-minute information grams. The rectifier is made up of alumi- on electricity, from the simplest principles to complete and economical num and block tin strips in a solution of operation of a central station. You will be told the things you need to by 6" know about motors, generators, armatures, commutators, transformers, sodium phosphate, contained in a 1" circuits, currents, switchboards, distribution systems-electrical ma- test tube. Eight of these rectifiers are used. chinery of every type, installation, operation and repair-wiring for A layer of oil on the surface of the electro- light and power-how to do it mechanically perfect, in accordance with the National Electrical Code-wiring of finished buildings- lyte prevents it from evaporating underwriters' and municipal requirements-how to do the complete it completion-illutnination in its every phase line is to the pri- job, from estimating to The 110 volt connected -the latest and most improved methods of lighting-lamps and light- mary of a 110-220 volt transformer. The ing effects, etc. secondary of this transformer has four taps giving voltage variations ranging from 110 to 220 volts. The secondary is connected Way to Bigger Pay to the rectifiers and paper condensers so as The Sure to double the voltage by -2,ing the same cir- 1)1G salaries are paid in the electrical field for expert knowledge. The man who knows cuit as figure 5. It is then connected electricity in all its many phases--the man who has completely mastered the subject from his own job and name his own salary. Fit yourself for to bigger position through a choke coil to the D.C. terminals. A to Z-ean pick stations and the are connected two by knowing electrical practice complete-inside and outside work-central Across the D.C. terminals whole subject. Croft will teach you. He will take you in quick, easy steps from the simplest sets of paper condensers for filtering pur- principles to the complete and economical operation of a great central station. The Croft -trained poses. These condensers are connected in man wins because he knows the "why" and the "how" of modern electrical practice. series so as to reduce the voltage across each condenser and thus prevent the condensers by an Expert from being punctured The D.C. voltage Practical Electricity Taught is adjustable from 300 to 600 volts, by The No course, no set of books, offers a quicker, Croft has been through the mill. His knowl- means of the taps on the transformer. than the edge has been gained by shirt-sleeve contact it is impossible surer method of mastering electricity He has worked his potential is so constant that It is founded on practice-on with electrical problems. A.C. hum in the loud talker Croft Library. way up from the bottom to the top-from to hear any work as it is actually done. It is jammed from apprentice lineman to electrical engineer for when used for amplifying purposes. cover to cover with the kind of hard-headed, one of the great electrical companies. Now want. Written so that is made up pay -raising facts you he heads his own consulting company, and his The core of the transformer the beginner can easily understand it, yet so name is known in every corner of the elec- of laminated transformer iron and has a sound, so thorough that it is the daily guide trical world. He is the one man above all cross-sectional area of 11/4" by 11/4", or 1.56 of thousands of highly paid electrical workers others who can show you the way to perma- square inches. The outside dimensions of and engineers. nent success. the finished core: are 5" by 41/4". The pri- Pay for these books as you go 450 of No. \\-hat tilt' Books Contain Easy Payments along. We have made thepayments mary winding comprises turns so low that any man can meet them. Only $1.50 in ten 24 B. & S. enameled magnet wire wound Vol.ime One - Practical Mathematics, days and the balance at the rate of $2 a month for 358 subject headings. Tells you how to on one leg of the core. The secondary wind- as a tool. nine months. These are the lowest-the easiest - use mathematics terms ever made on a high-grade electrical library. ing comprises 900 turns of No. 26 enameled Volume Two-Practical Electricity, 1,000 wire wound on the other leg of subject headings. The basic principles of We yon to test 4.I magnet all electrical practice. Just send the coupon our "antstate ments- out of this McGraw-Hill the core. Taps are brough Volume Three-Tracts cal Electricity, we want you to eom pare the Croft books with 1 A continuation others. Fill in and mail the coupon attached and Book Co., toe winding at 450 turns, 600 turns, 750 turns, 1,100 subject headings. 0 370 Seventh Ave. of Volume Two. we wül send you the entire set of eight vol- and the end tap at 900 turns. These taps umes for ten days' Free Examination. New York Volume Four Electrical Machinery, We take all the charges. the dead - what risk-pay all 4. I e a a e connect to the tap switch as shown; 1,400 subject headings. Contains You assume no Gentlemen:-I' man wants to know. obligation-you pay send me tile CROFT contact points are placed between each live every electrical nothing unless you decide to keep :L Stations. 509 me books. Then $1.50 in ten LIBRARY OF PRATICAL lever will Volume Five-Central ELECTRICITY (s h i p p i n g contact point, so that the switch headings. All phases of central days and the balance at the subject charges prepaid), for 10 clays' of the secondary station operation are covered. rate of $2 a month. Send the satisfactory not short-circuit a portion free. examination. for Light and coupon NOW and see the and when moving from one contact Volume Six-wiring books for yourself. 4I will anm $1.50 in ten days winding Power, 1.700 subject headings. Tells how ) $2 per monthuntil $19.50 has been point to the other. to do the big and little jobs right. , paid. If not wanted, I sollt write you Volume Seven-Wiring of Finished Send No for return shipping instructions. The design of the choke coil is very Buildings, 1,100 subject headings. The Money- 4.. (Write plainly and fill in all lines.) meat of wiring practice. simple. It consists of a coil of wire wound very the , F Name Volume Eight-Practical Electric Illu- Just on an iron core as shown at figure 8. The mination, 1,000 subject headings. Lamp COnf)rin Home Address transformer and the art of lighting properly, I core is made up of laminated City and State gap in the magnetic cir- iron, and has an air Company or Employer The function of the air gap is to 10 Months to Pay ! cuit. occupation S & I-3-23 increase the reluctance of the magnetic cir- 110 Science and Invention for March, 1923 suit. The function. of the air gap is to increase the reluctance of the magnetic cir- FOR DEPENDALEE cuit so that the iron will not become satur- ated, thus destroying its magnetic quality. rotection You NEED A The inductance of the thoke coil should be GENUINE at least 1i henries. The choke coil is de- signed according to the following formula, which is close enough for all practical pur- OR TjMATI C poses: THE PISTOL WITH A NAME AND WORLD-WIDE L- 3.19íc2 REPUTATION 1 OFR L=inductance in Henries n=number of turns in the coil l where 1=length of air gap in 25 Cal., R=-, inches, and a=area of air gap 7 Shot, a in square inches. R is the reluctance of the air gap. The $9 .95 reluctance of the iron is so small as com- 32 Cal., 8 Shot, pared with that of the air gap that it will be omitted here. If we use a core having a cross-sectional area of 1/2" x 1/2", or 0.25 $10.95 square An Automatic you can de - inches, and a 1/16" air gap, 1/16 I nd on. will not jam; 0.25 = 0.25. Substituting 0.25 for R, and safe; reliable. livery one tab/c new and perfect. Shoots regular American ammuni- Prì 1% for L, in tion,. Small size, easily carried. our formula, we have: Satisfaction or 3.19íí2 money bark. Sent postpaid. Buy direct from the lmporters. Send no money, pay postman on arrival. Pleasure 1%- Order Today. 3 10"X0.25 NASSAU IMPORT CO. CONN Solving we get 3322 turns as the value 150 NASSAU ST. (Dept. 5) NEW YORK instruments place a world of of n, which is the number of turns required pleasure, unnumbered opportunities in the coil to give an inductance of 1% for profit, henries. No. B. at your command. For two - 36 & S. copper wire will do FINE OLD VIOLINS score years they have been recognized for this coil. supreme by An electrostatic converter employing a On Easy Payments the world's greatest artists step-up transformer and magnetic rectifier in concert bands, symphony, opera and is shown in figure 9. This type of converter 30 Days Free Trial popular orchestras. will deliver a higher amperage than the con- allowed, no matter where you lives It not more than pleased with our values verters described above, and occupies less return violin AT OEIL EXPENSE-and no Exclusive features make space. It harm done. Ability to play the violin Conns easier has the disadvantage that the brings social and financial success. Geta to play. The most celebrated magnetic rectifier is not quiet in operation violin with a rich, mellow tone and it will artists, in- create in you a desire to master It. cluding the great Sousa, use and endorse and requires more attention than the elec- them because trolytic rectifiers. Free! Magnificent Conns are more perfect in The connections are the same as those of tune and tone, Album -Catalog have more reliable action, are figure 7, the potential at the transformer containing portraits of the easier secondary world's greatest violinists since Pag- to blow, more perfectly balanced, being doubled by means of the anini'e time, a half -tone of "Stradi- artistically rectifier and condensers. A tuned iron vi- varius In His Workshop," and the designed and finished. romantic story of The Ring of brator carrying silver contacts is magnetic- Musical Instruments. A postal brings More Conn saxophones are sold than ally connected to the transformer core as all to you FREE - no obi i gatìons. any shown. This vibrates in front of a per- CREMONA VIOLIN SHOP other make in the world. Simplified Depf, G-51 Chicago key manent magnet and makes contact with system, patented tuning device, per- two adjusting fect screws. The vibrator is scale, and many other exclusive im- slotted so that its vibrating length can be provements make them the choice of the adjusted in order to accurately tune it to Lear the great "jazz" kings. You frequency of the alternating current. Paul Biese of Chicago, This converter was successfully used by (top) and Max Fisher want the best; be sure V/031P91113aOM E of Los Angeles, (bot- the writer for operating a 10 watt radio tele- tom) are among the you get a Conn. phone transmitter. The hum was practically Make $75.00 a Week on the Side popular orchestra eliminated Establish yourself as a Photographic by means of the choke coil art iokly-d a ag Saar'par -- directors who endorse and der time FREE TRIAL, EASY E s leedlag Vh toanph r. 1' 11 show Conn instruments. condensers. you bow to stare your own business-or command a large salary. Send for my un- PAYMENTS. Send It should be remembered that one side of usual offer-It's only temporary- act Ose. at now for information the alternating current line is grounded. Aeoetoi will do. on International Studios. Inc., Dept. 7573 how to get any Conn and if any of the above circuits which do 3601 Michigan Ave Chicago. U.S.A. instrument not employ a step-up transformer are used for trial in for radio or Other purposes, which have your home. Conn is the a ground connection of their own, a short YOU CAN SAVE $35.00 only manufacturer circuit is apt to result. This difficulty may By recovering your old of auto top frame yourself be overcome in radio sets by a er e r the complete connecting e.$P5ar instru- small 7 and u fixed mica condenser in series with Vls .r mentation of a band. Post Paideddaa1 fte7c;n"rn the radio ground lead. iona toped,. with rear curtain. lomntm/omen.. and tack. completeca pltwed Highest Give o the name, year end model number of your ter and ere will tend you Honors at World Ex- catalog with ,a mplet positions. All Exclusive Conn ALCOHOL AS MOTOR FUEL LIBERTY TOP & TIRE CO., Dept. E-4, Cincinnati, 0. Features at No Greater Cost. Under the decision, announced by Commis- Dealers and agents throughout sioner Blair of the Internal Revenue Bureau, the country. Factory branches the sale of alcohol "for use in the in many manufac- large cities. ture of motor fuels" will be permitted when ONLY $10 DOWN $8 MONTH "to 100 10 arre summer home, and every gallons of ethyl alcohol there 2 C. G. CONN, Ltd. is added poultry farm, -room 356 one gallon of gasoline of that quali- house, 1 0 O. chickens, Conn Bldg. ty specified." overlooking 2 fine lakes, Elkhart Ind. near Shelby and Hart, Further than to say that the formula had Mich., country seat. Sur- rounded b y splendid been approved on the application of persons farms and orchards- Only interested in the motor fuel industry, $095. Treas- TOPPING & CO. ury officials declared they had no information 810 Reaper Block as to the intent and scope of the use of which Chicago. Ill. the formula was to be put. The formal announcement by the Treasury Experimental set forth the following specifications Electricity Course in as those 20 Lessons which would be required for the gasoline By con- S. Gernsback and H. W. Seene. E. E. A tent of the new fuel : course of the theory and practice of Electricity for the Experimenter. Every phase of experimental "Volatility-When 5 per cent. of the sample electricity is treated comprehensively in WORLDS glish. plain En- has been recovered the New experiments are described and ex- LARGEST MANUFACTURERS thermometer shall not plained and nearly OF HIGH GRADE every application of Electricity BAND AND read more than 65 degrees centigrade nor in modern life is given. 100 pages -400 illustra- ORCHESTRA INSTRUMENTS less than 50 tions. Flexible cloth cover, 75c. postpaid. Stiff degrees; when 50 per cent. has cloth rover, $1.25 postpaid. been recovered the thermometer shall not EXPERIMENTERDep PUBLISHING YOUR, Book 53 Park CULTIVATE MUSICAL BUMP read more than 95 degrees." Place, N w York City 1105 Science and Invention for March, 1923 New Process Colors How Inventive Ability Is Now Black and White Movie Films Being Developed By LEWIS YEAGER Develop your inventive ability. A single idea, which (Continued from page 1054) solves one of the millions of the world's daily problems can make you independent for life. Fifteen famous inven- the emulsion on the film, so when each of tors now make every step in invention as simple as the colors go back through the lense, it develops your native on the film. Blue has A. B. C. Spare time at home quickly has a distinctive effect for inventions helps you become successful. a different effect from red, etc. A simple instinct - example is cited. Ideas for Inventions Everywhere a before us, the FOR a long tittle it was commonly believed that Suppose we have stairway a matter of pure luck- Whatever your position in life, whatever kind of work every invention was which must be the next yellow, the next sud- YOU do, you are constantly meeting problems first step red, the result of some happy inspiration that kind of kitchen Mr. a man's brain, and solved. Even so small an idea as a new green, the next blue, the next violet. denly flashed through knife for your wife may prove to be the making of your which made him fabulously rich without the slight- some little Taylor takes a photo of the stairway with for your- fortune As an office worker you may invent standard est effort or thought. But you can prove method which will simplify work, or if you live on a farm. the ordinary movie camera with self that this is not so. You can prove for yourself you can invent some idea to meet one of your every -day negative film. He develops the negative that invention is the result of thinking and acting needs. definitely exact, scientific lines. The work you do, the life you lead, the problems you and prints a positive from it. This he later along meet, all present you with innu- bleaches by a special process, until the im- Suppose, when you went merable opportunities to invent it home tonight, you found a things. All you need is the abil- age appears to have disappeared, so that window rattling. Through ity to think inventively-to trait which the your mind to connect two ideas- resembles a piece of film from your mind would flash, almost the ideas of a regular order lest as you connected emulsion has been removed. The various instinctively, the tattling window and the wedge have of thoughts which character- -and you can be assured of success. colors due to the wave length of light ize the conception and com- each left a different trace, and the red will pletion of every invention the Learn How to Invent at Home other world has ever known. First Take advantage of the opportu- select red 'dye, while rejecting the nity offered you now. Get the you would recognize a prob- fifteen colors ; the blue will also select its respec- advice and the help of the lem to be solved-the rattling fatuous inventors who tell you all tive dye. of the window. Then you the secrets of invention. Learn Mr. Taylor says the duplicate positives arc would think of several prin- how to develop your ideas so they negative. The ciples of science or mechanics will make money for you. printed from a black and white which would solve your prob- This is the first course in prac- positives are treated with mordant and lem. You might think of the tical invention that has ever been devised. In simple, easy -to -under- select dyes of certain chemical groups. In scientific fact that if you are told how poured water on the frame, stand language you we find an operator in charge successful inventors work ; you leant the laboratory the wood would swell and hove to think along inventive lines; of each coloring machine. The color wheel tighten the window. You you learn the short-cuts to success- applies the respective dyes is watched might think of using a nail. ful invention; you learn how to which But what you most probably use the secrets of invention that carefully by an operator. would do, would be to use the convert a simple little idea into stoney. Mr. Taylor gives the following explana- oldest mechanical principle But you learn more than just leaves the filin selective known to man-the wedge. how to invent in this fascinating tiou: Bleaching course. Thousands of inventors to dyes of a certain chemical group, only What Invention Is have lost the profits of their inven- of the tions simply because they didn't for absorption in certain portions Brought down to its sim- know how to patent and sell their image, while another part of the image is plest terms, that is exactly ideas. This complete course shoes a different chemical what invention is-the com- you just how to apply for a patent. selective to dyes of bination how to protect your rights when of two and how group. ideas; a prob- your patent is granted, to dispose of your invention so The film after being given the required lem which must you will get the greatest returns he solved and a possible. coloring baths, is dried and a colored vase fact of mechan- Not one step in invention has the size of a pea on the film will display all ics or science been omitted- Everything you want of a great piece of Sevres which solves the Little Inventions Like These Have to know about invention-develop- the original colors problem. That Brought Fortunes to Their ing your ideas, securing informa- or of Cloisomé. way In, enters. tion you need, how to apply for is the patents, how to protect your rights. There arc 16 individual squares of mo- every invention how to sell your invention-are has been made. so when you have t that film to the foot; each square is tohu Up, step by step, tion picture So, although tnntpleted the course you have a wealth of in - Raymond i'. Y ales, who upon thousands of a small still picture in itself representing you may never with 14 othe r famous fttrnta tien worth thousands its own bit of action and having its own im- have thought of inventors, now make it dollars. it in just this easy for you to learn portance and relation, to the entire scene. way, every tinte how to invent in your FREE-New Book on Inventive pictures to one foot, 160 you solve sonic spare time at home. Science Sixteen separate problem in your A wonderful new book has just come separate pictures to ten feet, 16100 pictures to daily life at from the press that tells all about the 16,000 to 1,000 feet. traveling- or in business --you are an inventor; Science of Invention. It tells you how to avoid 100 feet and pictures home, thousands must be an exact duplicate of you use the principles of thought and action which the pitfalls that have brought failure to Each picture govern the Science of Invention! of would-be inventors. It tells you how to learn picture in the entire length of fatnous every other You can see, therefore, how easy it is for you to develop the secrets of practical invention, which of of heart- film so far as density and color are concern- Your natural instinct to 'fix things." The same processes inventors discovered only after years the continuity of the film's thought that almost instinctively told you to fix a rattling breaking effort, and discouraging mistakes, and it ed; otherwise, window with a wedge can be so well developed that you can tells you how to do this in only 15 minutes of luminosity would be interfered with to the learn to invent other things almost as easily and quickly. your spare titile each day. This fascinating book You know, too, that every invention is made only by think- inter- extent that the screen would appear to be And every inventor is agreed that the will ne sent to all those who are genuinely ing INVENTIVELY. 15 famous inventors. a series of flickers and the picture not fit of Science are so so easy ested. Get the advice of these of trainitive ng or education, can can easily learn the This has been a very serious learntciples that anyone,n regardless Let them tell you how you to exhibit. prie,develop himself to become a successful inventor! secrets of successful invention. block to experimenters who have this Book today, as only a limited num- stumbling Be Taught as a Science!" Send for color to the cinema film. Edison Says: "Invention Should ber are available for free distribution. Send the attempted to apply But although the fact that Invention is governed by a few or postal -card will been uni- coupon below NOW, or a letter It seemed that they could not duplicate and simple, easily acquired. fundamental principles has do. There is no cost or obligation. This bureau versally recognized no one ever thought of putting these prbt- for this one reason alone, if they were for- interested in is not connected in any way with patent attorneys riples in black and white so that everybody is to help ambi- tunate enough not to have other difficulties, invention could read them. In spite of the fact that Thomas or manufacturers. Our only work A. Edison made his famous statement that Invention should tious men and women to develop their inventive their processes were rendered useless. be TAUGHT as a science, thousands of people continued to ability-to become successful inventors, by a very in- work blindly, doggedly, haphazardly to perfect their ideas. Taylor's process duplicates fa- to But now you CAN LEARN HOW to invent. Fifteen i genious device and I saw, on my visit mous inventors have at last given to the world the laws and have shown every am- i film, of of Inventive Science. They the Lasky Studio, 200,000 feet of all principles They are one to the other, bitious man and woman HOW TO INVENT. BUREAU OF even luminosity from end TEACHING Invention, exactly as other people are teaching I ready to be assembled into a big super pic- law, medicine, bookkeeping. Instead of spending years grop- ing blindly, instead of wasting your time in useless, heart - ture and shipped to the different cities of drudgery, you learn how to complete your ideas INVENTIVE to caking OFBIiNVENU - quickly; you learn how to think so you are sure to succeed. the world for exhibition. lIc You a Fortune I was permitted to see sections of the new One Little Idea May Bring SCIENCE, ; ,Dept T73, W slier B de. with every new discovery that the release and can say there was absolutely no With every new advance, Rochester - New York world experiences, more problems are coming up ---and more Bldg. I fringing such as is often seen on colored mo- inventions are needed to solve these problems. Now, as Wisner Please send me your free book, wanted, and the world will I tion pictures. Any depth of color required never before, are new inventions e:voce of Invention." pay a fortune to the man or woman who gives it just one of Rochester, I may be given. It is not necessary to re- the inventions it needs now. N. Y. sort to gaudy scenes on the water edge with But all inventions need not be enormously big. Little / NAy1F; ideas will bring you returns equally as great. Eberhard. Dept. 73 the new process. Even night scenes give the who invented the rubber on the end of a pencil, has been paid hundreds of thousands of dollars for his simple idea. ADDRESS same color effects as scenes taken in dazzling The man who invented the metal tip for shoelaces, the man sunlight. In the new release, a procession who conceived the idea of the "lumped" hairpin. the man as who developed the metal tape -measure: all have achieved PITT is shown where various colors of lanterns of success and wealth as great or greater than the inventors I are used and these hues are faithfully dup- large machinery. I licated on the screen. STATE. 1105 laa-+r111+ Science and Invention for March, 1923 How to Use Your Caunera Style OLIVER By DR. ERNEST BADE The (Continued from page 1076) New 1923 Model Now Ready Here is the latest and 1 1111 1 1 1 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 .: 111 1 1 111 111 11 1 1 1 1 1 1 11 1 1 1 111,1111 1 1 1 1 1 1 1 1 1 1, 11111111 1 1111 1 1 1 11111111111 11 111 1111111 1 1 1 1 1 11 a 11 1 13 greatest of all typewriters. Send NOW for complete The time required in setting up such an details of this wonderful. apparatus for taking a portrait will materi- NEW 1923 machine, ally increase the value of the finished and our money -sav- pic- ing offer. The Oliver ture, since the subject will have sufficient Quiet Speedster is the time to compose himself so that the features crowning achieve- will become more ment of 28 years of manu- natural. facturing. Another is Equipped with chapter the taking of pictures the NEW standard 3 -bank of children, pictures showing the lively, keyboard. ANY operator carefree folk in the happy abandon of can run it without loss of their time output. play. Such pictures are difficult to take and or Oliver No. 9 with $55.00 can seldom be posed satisfactorily. The Special Price Offer slvtoimy keáyment children Price, $55.00. Net must be observed either individually NOW, Cash Price...... 49.50 or in groups, and when exceptionally effec- Oliver No. 11 with newest improve- tive poses are noticed, they must be remem- ments. Monthly 75.00 $95 an Hour! bered. Then a suitable situation must be .00 payment price, selected having the requisite 0. Net Cash "Every hour I spent on lighting effects $5 SAVED Price 67.50 my I. C. S. and the children are to be posed in Course has been worth $95 to me! My this new 'this marvelous new model Oliver is offered to you at the position, my $5,000 a surrounding. But if one can take snap -shots lowest price and easiest terms ever offered for a standard year income, my machine. It has every modern improvement and many new home, my family's happiness-I owe it of the children unseen and unnoticed by and original refinements. No expensive branch offices. all to my spare -time training with the them, then these are to be preferred to the Simplified model and efficient manufacturing methods make International this price possible. What business man will hesitate to save Correspondence former as they will be far more natural and over $50 when he can get a BETTER machine at half the Schools!" spontaneous. For this purpose no cost of other standard typewriters? Don't doubt. Stake other sure. Write for offer and FREE TRIAL. Every mail brings letters from some camera is so well adapted as the graphlex, WEEK'S TRIAL FREE-FREE CATALOG of the two million I. C. S. students tell- but even it has its bad points as it seldom Send for this wonderful typewriter on FREE TRIAL FOR ing of promotions or increases in satisfies the high expectations demanded. A WEEK. Use lt. Test it. Compare it. Then after trial, salary as the rewards of spare -time if delighted, you psy a small amount down and the balance study. Two things must be noticed: first the focus on easy monthly terms with nearly a year to pay. If not. or sharpness of the picture must be correctly return it at our expense. You take no risk. Write today What are you doing for catalogs and FREE OFFER. with the hours provided for, and secondly, the correct and THE OLIVER TYPEWRITER COMPANY after supper? Can you afford to let most effective pose must be obtained. At 673 Oliver Typewriter Bldg., Chicago, Ill. them slip by unimproved when you can easily make them this point it must be said that no camera mean so much? is so well adapted for general One Flour a day spent with the I. C. S. portraiture as WE TEACH YOU will prepare you for the position you the long bellows camera,-f or this purpose it want in the work you like best. Yes, is still the ideal instrument. it will! Put it up to us to prove it. Silhouetted photographs give some very Mark and mail this coupon now! pretty results. Here the subject contrasts WHOAHOMET strongly, standing out against the back- For business or professional purposes a training in INTERNATIONAL CORRESPONDENCE SCHOOLS - ground, although all of the superfluous de- law establishes your position Box 6188-C, Scranton, Penna. both socially and Without tails of the profile need not be suppressed politically. It increases your ability to handle cost or obligation on my part. please tell me larger responsibilities, it how I can qualify for the position or in the subject before or eliminated. The background consists of safeguards your own or Which I have marked your employer's business, it enables you to decide an X: a large sheet of white paper fastened to the matters BUSINESS TRAININO DEPARTMENT of importance instantly, with a full knowl- Bueinees Management Ealeamanehip window frame. It must be entirely smooth edge that your decision is right, and it gains for Industrial Management Advertlning and free from folds and wrinkles. The sub- you the respect of all worth while people with ['Personnel Organization Better Letters ject is placed before whom you come in contact. Send for our free Traffic Management Foreign Trade the paper and the pic- booklet describing the scope and merit of our Business Law Stenography and Typing ture is taken from the room directly into courses and giving many helpful legal pointers. DBanking and Banking Law Bunineea English ['Accountancy (including C.P.A.) C1v1I Service the light after all other windows have been BNicholson Cent Amounting El Railway Bookkeeping Mail Clerk darkened. The length of the exposure de- BLACKSTONE INSTITUTE Private Common School Subjects pends Secretary High School Subjects upon the light transmitted by the Dept. 216, 4753 Grand Blvd., Chicago, III. Business Spanish French 011lustrating paper. When the diaphragm is almost closed, TECHNICAL AND INDUSTRIAL DEPARTMENT 2Electrical Engineering a second or so will be sufficient provided the Electric Architect background Lighting OBlue l'rint Reading is comparatively bright. If the New Single Phase Mechanical Engineer Centractor and Builder negative A. C. Motors Mechanical Draftsman Architectural should show too much detail, it can OMachine Ship Practice Concrete Draftsman be partially removed V.. H.P -110 GENERAL Railroad Positron Builder by simply over expos- volt, 60 cycle ELECTRIC OStructural Engineer ing 1725 speed, l'it ,A UZI Gas Engine Operating Chemistry the positive made from it. ` 13.P $39.00 OCivil Engineer Pharmacy complete with 6 includes pulley Autemoblle Work Another method of arriving at the same cord, plug and Surveying and Mapping tAirplane -.,- 110/220 volt, Engines result is to place grooved pul- 60 -cycle, lMetallurgy Agriculture and Poultry the subject before a white ley. $13.00 1725 Steam Engineering Radio ... - speed, Rep. Mathematics background and, with diaphragm closed, Same motor Ind. Type. Name make a rapid time equipped with Remittance exposure. buffer and ONE YEAR When must arum - Street Address 6-26-22 printing silhouettes, frames, which grinder. $25.00 GUARANTEE pany all orders. are either round or oval in shape, are used, Satisfaction guaranteed or money refunded city State they should never he angular. Illustrated Catalog of Motors and Supplies FREE Occupation Peculiar as the silhouette photos may be, Persona residing HYRE ELECTRIC CO. in Canada should send this deepen to the those which show the details of the ex- International Correspondence Schools Canadian, Limite4. 631-W So. Dearborn St., Montreal, Canada pression as well as the silhouette are far Chicago, Ill. more unique and interesting. They are modern in all that this word implies. Such Keystone Institute pictures can be taken both in artificial and MAKE MONEY "The Service School" natural light, but care must be taken that the A fully equipped school with expert instructors, shadow is not 'distorted. Artificial illumina- AT HOME organized to give intensive instruction in tion is best 2 -Year Courses accomplished at an angle so CAN earn $1 to $2 an hour writing show cards Electrical Engineering that the silhouette lies in front of the profile. lIOUat home in your apare time. Quickly and easily Mechanical Engineering learned by our new simple Accounting Business The subject is placed before, and quite Inatructograph and Administration close method. No canvassing or soliciting. We teach you 16 weeks' course in Automotive Engineering to, a white background. how, guarantee Day and Night you steady work at home, no matter Classes. Graduates are sought by where you live, large and small industrial establishments and aro and pay you cash each week. Full filling hnportant positions in all sections of the SPOT FOUND ON SUN particulars and booklet free. Write to -day. country. Write for information on subject that AMERICAN SHOW CARD SYSTEM LIMITED interests you, to Keystone Institute.. Address A spot on the sun was discovered re- Authorized and Fully Paid Capital. One Million Dollars "The Principal," 133 North 4th Street, Reading, Pa. cently by Henry Pennywitt, official fore- 110 Adams Bldg. Toronto, Canada. caster of the United States Weather DO YOU LIKE TO DRAW? Bureau. **************************** Cartoonists are well paid (1885A) "We have not fully measured the spot," ( OPEN YOUR EYES to We will not give you any grand prize said Dr. Burns of the wonders above and If you answer this ad. Nor will the Allegheny Observa- get refreshed and * we claim to make you rich in a tory, "but we suspect it is one of strengthened. Learn the week. But if you are anxious to those stars * spots with a Radium )I+. develop your talent with a suc- which periodically make their ap- Star Map. It shines in cessful cartoonist, so you can make pearance. This one is the dark. Constellations * mosey, send a espy of tide picture with to the side of the shown by shining 6 cents in stamps for portfolio of cartoon. lines between radiant stars. sun. Were it more to the centre we Sample star group free. 4 ft. map, $8.50. and sample lesson plate. and let ae explain. by leading Used * The W. L. Evans School of Cnrtooning might have some serious weather disturb- schools, colleges and universities. 814 Leader Building Cleveland, Ohio ances." ********** 6******* S***a******** Science and Invention for March, 1923

.,,1ru,ummml,.lull,mul,m,,,,m,,,,,,l,,,,,,mu,,uno,..,,,,,,,,l.,l1,,,1111111111111111,,,ae1,,,,,,,a, Waterprt ®fin M®thpr®®fSInr' by Egect;tì'P1cIltIY By ISMAR GINSBERG, B. Sc., Chem. Eng. (Continued from page 1063) all be treated in the same machine, or rather on in either of two machines, depending whether the cloth is silk or wool, or cotton or linen. The waterproofing effect that is attained in the fabrics is remarkable. A common muslin, treated by the Tate process, will be able to resist as much as 16 inches of water pressure without allowing a single drop of water to penetrate the fabric. The waterproofing is resistant to washing, al- though in time its original intensity will be lost. A coat or a suit of clothes, made of Tate waterproof woolens, can he dry cleaned and still retain its waterproofing. There. is no other known process of waterproofing which can withstand dry cleaning. process has been used with great The Tate Systems transcontinental telephone line crossing Nevada success in waterproofing tent cloth. Circus The Bell tents have been made from this cloth and have stood up under the severest weather conditions for extended periods of time. of Speech Similar good results have been obtained Highways from Tate treated sailcloth, awning cloth, United dustry have done what fami- hunting Necessity made the woolens used in making overcoats, States a nation of pioneers. lies have done-they have suits and out -door clothing. The rain can- to many places and not penetrate a Tate treated raincoat, and Development came to us only spread moreover the raincoat can be worn in en- the wilderness. made connections in still other not by conquering tire comfort, for the Tate process does For a hundred and fifty years places. destroy the ventilation. The uses to which this has pro- be put we have been clearing farms Obviously, this process of waterproofing can a national community are too numerous to be mentioned here. in and rearing communities moted fact, wherever the garment or the particular desolation was-bridg- of every -day interest which materials where product that is made from textile ing rivers and making roads characterizes no other nation has to withstand the passage of moisture, It has given the it has to possess -reaching out, step by step, in the world. in other words wherever whole country waterproof properties in order to render to civilize three million square people of the proper service, there will he found a use miles of country. One of the the same kind, if not the same for the Tate process. results has been the scattering degree, of interest in one an- has single One of the most interesting tests that of families in many places- other as the people of a been made up to the present time to deter- of parents city have. It has made neces- mine the efficacy of the Tate process was the separation re- of brother and sary facilities of national com- on the motor boat, Speejacks, which and children, us cently completed an eighteen month trip brother, by great distances. munication which keep around the World. The awnings and spray live in touch with the whole coun- Tate To -day, millions of us cloths on the boat were all made from in places try and not just our own part treated cloth. The awnings were never and make our success even in hurricane weather, from those where we were of it. taken clown, not far service and not a single drop of water came through born, and even those of us The only telephone the canvas. The results were really remark- in one which can fully serve the encountered the who have remained able for the Speejacks place have relatives and needs of the nation is one severest kind of weather in its record -break- of the people ing trip. Furthermore, today, after so much friends who are scattered in which brings all service, the canvas is completely waterproof other parts. within sound of one another's as it was on the day it was first installed. business and in - voices. In the words of the owner, Mr. A. Y. Again, of the trip was due BELL SYSTEM Gowan, the success COMPANY to the perfect construction of the boat AMERICAN TELEPHONE AND TELEGRAPH waterproofing and of the engines, and to the COMPANIES secured through the Tate treatment. AND ASSOCIATED Service, and all directed There is one other important character- One Policy, One System, Universal istic of the Tate process. Woolens, that are toward Better Service waterproofed in this way, have been found to be mothproof or moth -repellent as well It The significance of this fact is self-evident. Better Work and More of -THESI ARE THE RESULTS OBTAINED TO AN AMAZING DEGREE BY The fact that Tate treated woolens are HUNDREDS OF USERS OF really moth -repellent has been proven by Bench Saw scientific experimentation, extending for a Boice Junior period of over one and one-half years. A wonder olly Inavi ice I. 11nnpari, ail were carried out in the Massa- metal machine designed for accurate These tests and speedy sawing, ripping, grooving, chusetts Institute of Technology. Colonies etc. Cuts 1'k" stock. Dadoes SS" of moth larvae were bred on garments, deep and t'a" wide. Driven by V. or made from Tate treated 1/3 h. p. motor. Special saws cut which had been type -metal, bakelite, brass, etc. Port- cloth and which had been worn for over a able. Attaches to lamp socket. year before the test was made. It was Write for descriptive literature on that the larvae could not subsist on the Junior Bench Saw, i" Jointer. found 11" Bench Band Saw, Bench the Tate treated fiber. It was not that the Drills, Motors, and Larger Bench chemicals poisoned the larvae, for the Sawa. chemicals are absolutely non-poisonous, but W. B. & J. E. Boice, Dept. S.I. 3, 114 23d St., Toledo, O. simply that the animal could not eat the sr woolen fibers, treated in this manner. The Tate treatment mothproofs the fabric. con- HAVE YOU SOMETHING TO SELL OR EXCHANGE? properties of ferring upon it moth -repellent A classified ad in SCIENCE AND INVENTION will reach over 160.000 at a cost et only 12 cents a word. indefinite duration. 1108 Science and Invention for Marc/l, 1923 AnGwers to 1Ptl1lzzIlt s H®w t® mock -Up A YOU CAN EARN (See page 1071) HARD-BOILED OR SOFT? TrensmIl4ikeT But4®n t® There are several tests for a hard-boiled egg. First, it will spin readily on the table. MeHe en Efficient 5OA Week Second, if it has been recently removed from the water any drops that cling to the shell Loud IreIlkes- six months from now-if you very quickly evaporate. And third, as the waiter said, the contents of the egg are sign the coupon at the bottom rigid. A Transmitter button with a few dry of this column today. BOILING WATER WITHOUT INCREASE OF cells and a telephone receiver will make a HEAT remarkably simple and efficient loud This very interesting experiment, which talker. A Microphonic amplifier of this We will teach you in half a year's time was probably performed for the first .time type is just the thing for use with a radio from the day you enroll as a home stu- by Benjamin Franklin, may be carried out set. The weak music and signals may be in following manner: a dent the vital principles of Electricity, the Fill flask half amplified many times their original value. full of water : boil for a minute on the stove; is and you will be supplied at once with the remove the flask and stopper it very tightly It possible to entertain a large audience big laboratory outfit, shown in this adver- with a rubber stopper. On inverting the with a simple radio equipment if a trans- tisement, and other outfits as fast flask under a stream of cold water, the water mitter button is used in the circuit as as you explained require them, in the flask will he seen to boil vigorously in diagram A. absolutely free of cost. for some little time before it ceases alto- You will also receive personal instruc- gether. The cost is extremely low and the re- tion from the President of the school. This experiment is frequently used to il- sults are comparable with those produced lustrate the effect of pressure on the boiling by highest grade of expensive loud talkers. point of liquids. Thus water normally boils As may be seen in the diagram, two at 212 degrees F., but if the atmospheric dry cells or a small storage battery are pressure is low, as it is on high mountains, the liquid will boil at a much lower tempera- connected in series with the transmitter ture. The effect of pouring cold water on button and a 4 to 75 ohm telephone re- the flask is to condense some of the water ceiver. The transmitter button is secured vapor above the hot water inside and there- to the diaphragm of the telephone in the by materially reduce the pressure there. The radio receiving set. To accomplish this water then boils, but at a much lower tem- properly, scrape off the enamel (if dia- perature than it would if put in an open dish. phragm is enameled) on the face of the HERO'S FOUNTAIN diaphragm and solder the small hexagon As soon as water is poured into the basin nut supplied with the button to the exact (A) some of it at once passes down tube center. Care should be taken that the (B) to reservoir (C) thereby increasing the thin diaphragm is not bent or otherwise pressure of the air in this chamber. This pressure is then transmitted through (D) to #.9h res 4-75, ohm chamber (E) from which it forces water up /phone receiver through (F) to the fountain. As the water falls hack into basin (A) the action is re- This is Laboratory Outfit No. 1, given to peated, not indefinitely, alas, but until the every home study student. It is not a toy reservoir (E) is empty. outfit. and in a month after you have had it you can do anything an ordinary electrical PROOF OF THE EARTH'S ROTATION worker can do. 4V Objects dropped down sleep shafts have /sao Ohm isoo Ohm been observed resin. phone /receiver Have you a Radio receiving set? If you have, to fall toward the eastern wall you can listen to two lectures a week delivered indicating that the surface of the earth is from our Broadcasting Station by our Presi- rotating faster than the bottom of the shaft. dent. If you haven't a receiving set, you can 22V. hear these lectures at places in your home town, But perhaps the most interesting demon- that we will send you to as soon as you enroll stration of the earth's rotation is exhibited as a student. by a Foucault pendulum which consists of a heavy bob on the end of a long flexible You need not be told that Electricity offers harmed. The transmitter a better chance for advancement and a bigger wire and supported at the top. If started button is then starting salary than any other trade or pro- vibrating in one plane, say the north and screwed into place. Connections, as shown fession. south, it will gradualy shift the direction of in the diagram, are made with flexible its motion it With our certificate of qualification you can until has made a complete cir- wire. A horn may be placed over the ,.nter this great profession at a salary of cuit in a time which would be twenty-four low resistance receiver if desired. When 550.00 or more a week, and as you advance hours if the experiment were conducted at the radio set is properly tuned and signals in knowledge and expertness, your salary will the pole and less full be increased surprisingly. than a circle at any are being received, the transmitter lower latitude. At the equator the direction button is operated by the We operate, in Milwaukee, the largest Elec- of its motion would not shift at all. This vibration of the dia- trical School in the United States. With the experiment thus shows visibly the turning phragm of the receiver. As the receiver help we offer students, who study at home diaphragm vibrates, the mica diaphragm an hour or two each evening, through the of the earth beneath the pendulum. President's lectures given in our Radio Broad- PRACTICAL LEVITATION on the transmitter button also vibrates. casting Department, reaching every city, town To begin let us The carbon grains are compressed at and hamlet in the United States, you get, with suppose the balloon twice a week, free, knowledge that will help :sod load to be just heavy enough to make varying pressure; the current flowing you amazingly in your studies. it sink in air. Then if some compressed air through the local battery circuit is thus is The admitted to the cylinder, the density of the varied and results in an amplification of lessons are written in simple language, air will be and anyone who can read a newspaper can increased so that the balloon, the sounds in the low resistance telephone understand them. will now displace a greater weight of air loud -talker. than it did formerly. Now as the buoy -ant We will make it easy for you to become Diagram member force on a balloon is equal to the weight of B, which includes a step-up of our great home student body the you will sign the coupon below. It is air which it displaces, it is evident that transformer, is to he used with loud talk- het not to delay, as our offer will be with- the buoyant force should now he sufficient ing receivers of high resistance. The pri- drawn when one thousand additional students to cause the balloon to rise. On reaching the mary of the transformers should have a arc enrolled. top it strikes the upper lever, thereby open- resistance of about 75 ohms. An ordi- ing valve V, releasing the excess air and re- nary telephone induction coil will serve as Extension Division, ducing the pressure of the cylinder to nor- the transformer in this circuit. School of Engineering of Milwaukee, mal. The balloon then sinks of its own Dept. F3, 415 Marshall Street. Milwaukee, Wis. weight only to strike the lower lever, readmit You can get the above -described trans- some air and thus start the cycle all over mitter button FREE in subscribing Please send me free and without any obligation on again. to my part, full details of your special offer home "Practical Electrics Magazine" at $2.00 to stu- THE HYDROSTATIC dents in Practical Electricity. PUZZLE per year (12 months). Send your sub- The pressure produced by the weight of scriptions today. Name the man and piston must equal the pressure of the height Make all remittances Address water of (H) above the level payable to Prac- of the piston. Then 200 / 2=62.4 H (62.4 tical Electrics Co., 53 Park Place New City State being the weight in pounds of a cubic foot York City. í of water). Or H=1.6 ft. -Aa,, Science and Invention for March, 1923 1109 A Chemistry Laboratory for $7.00

Think of it, fellows ! Here is a real chemistry outfit with regular chemical apparatus that performs those fascinating, actual chemical Instruction Book I CHEMISTRY . experiments. ¡ 1 CHEMICAL ;

" This outfit is not a toy, put up merely to amuse, but a practical EXPERIINFMER laboratory set, with' all the chemicals, apparata and reagents neces- TstL1.Co LABOReTORTOuTm sary to perform real work and to teach the beginner all the secrets of inorganic chemistry. With this outfit we give free a book con- lfECae e S taining a Treatise in Elementary Chemistry, useful data and recipes. and 100 instructive amusing experiments.

DESCRIPTION OF THE OUTFIT

The outfit consists of forty-four (44) chemi- are: Division of Matter: This is a Treatise on deals with theory cals ' all C. P. (chemical pure) put up in ap- Elementary Chemistry, and the propriate wooden boxes, glass bottles and her- of the Elements, Molecules and Atoms, etc. metically closed jars. The acids are put up in glass bottles, with ground-in glass stoppers, and there is a sufficient quantity of chemicals 100 EXPERIMENTS supplied (mostly one to two ounces) enough to make dozens of experiments with each. How to make chemical tricks; how to make invisible and magic inks ; how to test flour; The apparats furnished are all of the best how to test soil ; how to make chlorine gas and of standard laboratory obtainable make and smoke (German War Gas) ; how to bleach cloth size and shape. 17 pieces of apparats furnished and flowers; how to produce oxygen and hydro- with this outfit. gen; how to make chemical colors; how to test The instruction book is a real Chettiistry acids and alkalies, and hundreds of interesting Course for the Beginner. Some of the Contents hints and formulas.

ELECTRO $700 Instruction Book Every Fellow Wants

A TREATISE ON ELEMENTARY the ELECTRICITY

100 Electrical Experiments

r"ELM n, s fifth legs" BOY'S ELECTRIC

CIRO IMPORTING CO. MST paw roas, u. TOYS

The Boy's Electric Toy contains: Enough material to make and complete over wenty-five different electrical apparatus without any other tools except a screw- driver furnished with the outfit. Student's chromic plunge battery, compass - galvanometer, solenoid, telephone receiver, electric lamp. Enough various parts, wire, etc., are furnished to make the following apparatus: Electromagnet, electric cannon, Magnetic pictures, dancing spiral, electric ham- mer, galvanometer, voltmeter, hook for telephone receiver, condenser, sensitive microphone, short distance wireless telephone, test storage battery, shocking coil, complete telegraph set, electric riveting machine, electric buzzer, dancing fishes, singing telephones, mysterious dancing man, electric jumping jack, magnetic E geometric figures, rheostat erratic pendulum, electric butterfly, thermo electric ,Menu:c Foue[I motor, visual telegraph, etc., etc., .. a jc-_ btes nr[Me aest This does not by any means exhaust the list, but a great many more apparatus ------can be built actually and effectually. can be r ì. With the instruction book we furnish one hundred experiments that - with superb illustra- ,r .,-,'..,1 made with this outfit, nearly all of these being illustrated ,.: tions. No other materials, goods or supplies are necessary to perform any of 25 : DAKt_Tr` the one hundred experiments or to make any of the apparatus. Everything C'1 by the means of this outfit, two bands J _.: can be constructed and accomplished and a screwdriver. R1 The outfit contains 114 separate pieces of material and 24 'pieces of finished articles ready to use at once. .t4 l We guarantee satisfaction. 1f The size over all the outfit is 14 x 9 x 2%. Shipping weight, 8 pounds. "The ili 3 Electric Toys" outfit as described, $7.00. Immediate shipment. f Boy's .C,eaeyn L NY lccc.oiclio+r ,t =w.u lE ç.c-afucTei11_ 1L B SEND FOR YOUR SET TODAY REMEMBER JUST CLIP THE COUPON-DON'T SEND MONEY ELECTRO IMPORTING CO., 233 Fulton St., New York City

ELECTRO IMPORTING CO., l ELECTRO IMPORTING CO., I 1 233 Fulton St.. New York. 1 233 Fulton St., New York. 1 t Please send me by express THE ( Please send me by express THE BOY'S I CHEMICAL LABORATORY. If I don't ELECTRIC TOYS. If I don't Ilke It I want It only like It I need not accept It. If I want I I need not. accept lt. It I I It I only pay $7.00 plus the few rents pharge.ay $7.00 phis the few cents express i express charge. I ( c I

. 1 Science and Invention for Marc/i, 1923 BUILD YOUR SET WITH BARAWIK STANDARD PLATE CIRCUIT "B" BATTERIES WE PAY TRANSPORTATION CHARGES EAST OF THE ROCKIES RADIO FREQUENCY AMPLIFYING You can make real savings TRANSFORMER on these batteries. Don't THE PRICES QUOTED DELIVER THE GOODS TO YOUR DOOR M995 Very site, lab ..$2.95 pay more. We guarantee r This transformer will get the them to equal any on the FAST SERVICE-TRY US AND BE CONVINCED long distance stations loud and s^nirrvaav market regardless of price. clear. Permits of 22balWaasella THIS GUARANTEE PROTECTS YOU -Examine the goods we ship you. ` easy sharp manta tows Absolutely uniform. Extra tuning. Helps cut out static, \ car tee' long life. They must suit you in every respect.- If yott are not satisfied with your and interference. hakes your ` - 111180 Signal Corps type, purchase return the goods at once and we will refund the price you paid. set sensitive enough to use a small size, 15 cells, 23 % colts. Each- .95v loop aerial. Enclosers In metal M114 Violable Large Navy size. 4%:4x3 inches ease affording perfect shield- ups, colts in giving range from 16% to 22% AGENT-DEALERS WANTED . ing. Suitable for panel or base 1% volt steps. Each $1.80 mounting. Recause of Its spe- We want Agent is every locality to handle our line et M188 Combination Tapped 15 volts 50 cell, -Deafen nods. cial design ten be mounted in 13xix3 battery. Tapped to give 45, 22%, II, Our Proposition Means Money to You any V. T. socket. Works with any- style of 19 t,4, IS and 16% volts. Handles bout de- tuner. Rate ranges 150 to 550 meters. Wir- tector and amplifier tubes. Each $3.55 Our prices save you money. The quality of our goods insures satisfied cus- ing diagrams inetudel. tomers. service will help you do a large business on a small investment. WILLARD "B" STORAGE BATTERY Our OUR SPECIAL AUDiO FREQUENCY Better results. - No battery , ,,_ .. , SEND FOR OUR CATALOG AMPLIFYING TRANSFORMERS noises. Cheaper in the long ` } As high as three stages rats run. Earley rechnetet by nut r. We have selected a line of goods --both completed sets and parts to assemble be used without howling due Battery Charging Rellfier. sets -that will enable you to supply every demand and make money. You can to proper impatience ratio, Leak proof glass jars. Will make a good income on our proposition with a very small investment. minimum distributed ea- last for years. Our catalog shows the merchandise you should handle, gives much radio in- pactt', low core losses and M205 (rice $9.00 proper formation and help you establish a succsesful business. Enclose 10c Insulation. Mount- will for ed style has b.tkell:e panel HOMECHARGER the catalog. Tell us what you can and want to do, and how much you can in- with binding post connec- BATTERY CHARGING RECTIFIER vest. We'll do the rest. Cons. Unmounted has core t'harge your battery at some over and coils assemble) with two holes In core night for a few tents. Simply con- For the Person Who Makes His Own Set for fastening to apparatus. nect to any 110 volt GO mete light Our catalog is interesting and valuable. Even if you are not interested in 91234 10 to 1 Mounted. Each $3.48 .%cket, turn on current and reetlOer M235 10 to 1 Venn Each 2.95 radio as a business you find many interesting things in this ',.es the rest automatically. Will will catalog and 91236 :I to 1 Mounted. Each 3.40 stork for years with- you will save money buying you sut plies from us. 91237 3 to 1 Unmounted. Each 2.85 out attention. Simple connections. dives a THORDARSON'AUDIO FREQUENCY tapering charge VACUUM TUBES e VARIABLE GRID LEAK AMPLIFYING TRANSFORMER Standard Brands-Cunningham Ra- Foncil mark type. Resistance c h i e h batteries - An espertally may Is' high grade -noulrl have. You dietran. Every ene guaranteed varied exactly as nanafornner with needed. 91160 Each 19e i correct char- so make It pay a new and perfect. We will still aelerlatlts for Cunningham, rofit charging your brand in stuck unless you specify GRID CONDENSER Radlotron or A. P. Tubes. dents' auto bat- otherwise. Wonderful results without teries. Long eotmect- Detector, UV200 4'300 Ea. M1G2 Mounting holes space) distortion M105 $4.45 to lugs on one, two or ing corda with pair MUO Amplifier í'V201 1'301 Ea 5 95 fit of above leak. Cap. 00025 MF. three steps. Low distributed f battery clips. M118 5 Transmitter 7.20 14e Watt l 91163 Name rapadt'. Fully mounted hake ransdertatien Paid. MUM WUII 1% v. Fil. Each , as 162 but higher bite panel. grade. Eneloseal In foetal Por 6 colt battery $13.95 MIeS Wall Socket. Each 49c N232 a to I Ratio. Ea. $3.69 48e ease. 39e 2C3 For 12 volt battery 13.95 M109 WDII Adapter. Rael, M233 6 to 1 Ratio. Es. 4.25 PHONE AND STORAGE "A" BATTERY MYERS TUBES GRID CONDENSERS Myers A compact style of con- RADIO CORPORATION A very high grade t Can be urteil in denser That in very satisfac- ter receptacle or ht any TRANSFORMERS tory. Conducting sheets and Audio F'teriuotcy Amplifying Transformer. for radio service. Guar- standard socket with dielectric are wound on filer strip with eye- Especially dsgned for Radintron tubes. 9 to anteed for three years. adapter listed. lets for mounting and connections. Each (2e 1 winding ratio. Properly eared fur will Mit3 lttr.i kit .i udion. Has 5 times ampli- 91170 Phone Condenser .001 Mfd. many more year' Meatinn of ordinary tubes. Oscillates any- M712' Each $6,40 give M172 Phone Bridging Condenser 0005 Mfd. RADIO FREQUENCY of service for filament where from 2 to 300 colts on plate. We include 91174 Grid Condenser .00025 MM. AMPLIFYING lighting. Made of best ear hest grade dieostat with each tube. TRANSFORMERS Earls Including rheostat $5.00 91176 Grid Condenser .00025 with pencil Range 200 to 5000 meters. Fur long dis- new materials. Full marts tenacity. The best bat- M116 Receptacle for above. Each Lod leak. Each 240 tance reception. tery buy on Ilse market. 91117 Adapter to adapt Myers tubes fort r TUPULAR M714 Each .....$5.95 'Pry one of these bat- in any standard scket. Each $1.08 GRID LEAKS AND CON- teries on your set for 10 DENSERS -MOUNTED STYLE OUR COMPETITOR AUDIO days. 1f at the end of MYERS CHOKE COIL Very convenient. Penn] is FREQUENCY AMPLIFYING that time you are not quit -k change of leave nr i"-. ,vY TRANSFORMERS fully satisfied Designed to work with Myers tulles. Brings emttenaers of varying ca- J with the battery and - return It In loudest algn.ls. Flexible While those are very low we will refund the purchase price. over a bmad band w--nos. `!... of wave lengths. Free from priced transformers, neverthe- M194 6 volt, 40 ampere sloe. Eaeh....$10.00 amplifier ah.ae Grid Luke Price less they will give excellent 91196 6 volt. S0 ampere size. 1250 atol distortion. Mounts in Myers special re- Each 39e Each..,. ceptacle. rt-ults. They are carefully Resistance .Hr-.iotance designed and tunefully made. BATTERY CLIPS MIle For Audio Frequency Antplldra- M850 S Meg. M855 -. )leg. tion Quantity praluetlon and small M198 Two for 28e $3.50 11851 1 Meg. 91857 :1. Meg. profits stake the low price M120 For Radio Frequency 91853 1 Cilp onto storage battery Amplifica- 5 Meg. 91859 5. Mee. ptnno ble. They tion 5.00 will equal In let eerale, lead coated. GRID results many transformers \lake posit ice nut -corrosive contact at all AND PLATE CONDENSERS selling at tooth higher times. FOUR -IN- Prie., each 55e prices. (4830 .00002:5 51fá. Coreet for Myers '- ONE Tubes. 91238 Unmounted. with wire leads $2.00 WIRE CONNECTING CLIPS M832 .0001 Mfd. For .perlai circuits, M239 e2=es- f. M834 .00025 V.201 Mounted, with binding poll connec- 111199 Per doren 30e - SCREW- Mfd. For C. and l'un. 301 tions $2.75 Small connecting clips (or quick- DRIVER M836 .0005 Mfd. For C. V.200 and Can. 1100 ly fastening leads urine binding M974 Each - 55e MOUNTINGS BARAWIK SPECIAL PANEL posts. etc. Handy and useful. Especially suitable for radio work. Will MOUNTING VARIABLE Every radioist should have at least a dozen. han- Bakelite base. Spring clip contact. dle any size screw used. Smaller drivers M840 Single mounting. Earh 324 CONDENSERS PORCELAIN BASE SWITCHES nest Inside larger one and are held in plate 14842 Double mounting. Each 57e M812 43 plate .001 Mfd. $2.29 Fitte white porcelain with seree rap. Made of steel, nickel fin- 6/814 Triple mounting. Each 784 91813 21 plate .0005 Sfbl. 1.80 (»sea. Copper contacts ished. Even radio builder ran use several 91814 II plate .00025 Mfd. 1.32 of these handy and blade*. Can be toils. "HONEYCOMB" COILS MOIS :3 plate Vernier . 1.05 u s e d a s antenna Carefully made --=fine looking These are especially high grade -itches. VACUUM TUBE SOCKETS tells. Highest efficiency. condensers and me guarantee 91385 Single Pole Low dietributrel rapacity ef- them to he morhanlrally and Single Throw. 4 , Our Special Socket. A won- fect, low reidatance-it(gh self electrically pence[. Fine pol- Each 20e derful value. Moulded entire- inductance. Very firm enamel lohel end plates of heavy MS87 Single Pole Double Throw. Each 32a ly of brown ttakellte. Four impregnation. Range given is haketlte. Shafts % inch diam- M384 Double Pole Double Throw. Each 504 binding post connections. in meters when varied with eter. Sturdy. heavy lurnintun alloy plates Right angled contact springs. .001 variable condenser. Mounter coils have perfectly spaced to Insure amooth, even reli- FILAMENT CONTROL RHEOSTATS M140 Each 39e . standard plug mountings. able rapacity. Our low prices save you money. Cnd.y-Wound on vulcanized Art Not Art Price These condensers are of the very beet make PORCELAIN BASE AND Tune Range No. Mntd. and are not to be complied with C."411) Ober. Adjustable to any panel. TUBE No. Mehl. many In- Complete with knob. 25 128- 250 91301 $0.39 M320 $0.89 ferior cheap minlensere nffered. We guarantee M138 kaeh .45e M144 Crasley for either panel 35 175- 450 91302 .42 M322 .93 them to please you or your money back. or table mounting 50 240- Rest grade. 36e 720 M303 .49 M323 1.04 High heat resisting 75 910 M3C4 .54 base. Diam. 320- 91324 1.08 COMBINATION VERNIER VARI- 2% in. cap 1'9 100 500- 1450 M305 .58 amp. Resist. 6 ohms. 1% in. Hlgb Grade ermihhutlmt type M325 1.13 ABLE CONDENSERS for or 150 600- 2000 91306 .63 04326 1.17 M824 t2i nlateobs. ,, knob with pointer. 75e value. panel fable mouuing. .0005iMfd. t7 lletel tube. BItt Insulation son 900- 250n M307 .72 M327 1.26 dial sod knell.Price....Swith MI32 Each 45e .s.1, 12150- r% base. On< of une best sockets 1150 3500 143C8 .78 91328 1.35 91826 43 plate 001 Mfd. with - j - 300 1500- 4 500 M309 .82 M329 1.36 and knobs. i POTENTIOMETER dial Price.... $3.95 Sante style 91144 Each 45e 100 2000- 3000 91310 .97 M330 1.57 The latest Improvement in eon- as above rheraist. Gores fine "B" 500 2400- 6160 -_ M311 1.12 battery adjustment Reststanee 200 or 300 ohms M331 1.63 densers consists of regular ra- 600 1000-11:000 91312 1.27 M332 1.78 N133 Each 98e stable condenser controlled by TWO AND THREE GANG SOCKETS 750 5000-120110 M313 1.43 64333 1.93 !area knob and dial mounted ? VERNIER RHEOSTAT These onckels 1000 7900-15000 913(4 1.70 M334 2.28 with a three plate vender eotdenser, which 1250 9750-19500 M315 1.92 91333 2.49 Is Gives exceeding b- fine control make It sly to controlled by separate knob mounted above 1500 14500-28500 M310 2.18 M336 2.65 p' of A" batten' current. A ne- 't 1 build detector knob on dial. This arrangement permits of ,,¡ very One resslt' for best receiving results. a n d amplifier MOUNTINGS tuning. Compact convenient mount- r units and make COiL ing on panel. high grade design and con- M(35 Each 78e 4 M340 Three -coil wont- a neat, ttaupaet strurtion. Finely lintahel. QUiCK ACTING VERNIER sot:maniike job. Perfectly made of ing $3,59 Me M341 Two -roll coo^nt- RHEOSTAT grade materials. Quickly mounted on pared ENCLOSED VARIABLE or base. Inc $2.69 Gives very fine control of cur- High grade fine looking CONDENSERS M147 Two -gang - test and can be awiteherl on or socket 81.83 nlomtings. l'oliahed One of the best tussle eon- M119 Three -gang - off instantly at any desired socket 148 black mmtaraitlon. deuers. Rigid, accurately point. 124 Each $1.19 Center receptacle sta- spaced aluminum plats. For- Porcelain Rase Rheostat for FIXED CONDENSERS tionery-, two outer ones mica ends. Engraved seale. Moulded cases, Snob cruel pointer. Clear ]j table mounting. Reedit. 10 nickeled alit:sitesl by knobs. Takes any. standard ohms. binding Puts. mounted mil. transparent rase. 91138 Each 7$e 91804 Each 48e M806 43 plate .001 Mfd. $3.95 COIL PLUGS M808 21 plate .0011.5 Mfd. $3.25 KL S ER VERNIER RHEOSTAT BRADLEYSTAT CARBON PRESSURE Made of moulded hekelite. Fits N129 Each 85e VERNIER any standard plug. Mounts any Regular $1.5e %aloe. Limited quantity at this RHEOSTAT standanl honeycomb colt. KNOCKED DOWN VARIABLE Price Current regulation Is ob- 91344 Each 50e CONDENSERS tained by changing of pres- You ran save money by assembling your own RADIO TUBES sure on carbon. This per- PANEL MOUNTING COIL PLUGS terldensers. FOrmica 'top and base. Com- Tubes lot winding toils. Strong solid material, ef mits of infinitely fine varia- Take any ntandart mounted colla. Matie of plete with all laits qat assembled. Co to- with amnoth glean surface. tion of current. Very durable. moulded takelite, emended on brackets. gether easily and perfectly. Panel moulding M950 Diameter Ii Inches, per fout 20c Resistance 15 ohms. Capacity M345 Stwtionaey. Each 89e type. M951 Diameter 3% inches, per boot 25e 2 t4 amperes. M346 Movable with anti -capacity handle. 91820 41 Plate .001 Mfd. $1.95 64952 Dianhelen 4 inches, lier foot 30e M131 Felt Cl 65 Each $1.10 M821 21 Plate .0005 Mid 1.60

Chicago's Original 102 South Radio Supply flouse THE BARAWIK CO. Beware of Imitators Canal Street CHICAGO, ILL. Science and Invention f ór Mai -ch,. 1923 RADIO GOODS ---DEPENDABLE QUALITY ---LOWEST PRICES FROM THEM AND SAVE MONEY CABINETS PRESERVE THESE PAGES-CRDER Fire looking cabinets FAST SERVICE -TRY US AND BE CONVINCED mildly built. Made of genuine solid ma- THE PRICES QUOTED DELIVER THE GOODS TO YOUR DOOR hogany in elegant YOU -We handle only the best goods, carefully tested and hand rubbed finish. OUR GUARANTEE PROTECTS that will checked by expert radio engineers. You are assured of Bettina ºuaranteed apparatus You will be proud of give results. And while our goods are best. our prices are lowest. Our goods equal get mounted In superior Our repu- your or surpass the claims we make for them. We do net attempt to deceive er mislead. one of these cabinets. RECEIVING TRANS- tation for fair dealing is our most valued asset. Hinged tops. Front rabbeted to take panels. ARLINGTON Panels not included. Prices ere transporte- FORMER TO ORDER year Order plainly, state Article Number, Description and Unn paid. HOW -Write Bank Will tune in all stations rep to 2.500 meters. Price et items wanted. Send Petioles or Express Money Order. Certified Cheek er ¡ Price Very efficient on short waves and for radio- Draft fer Total of Order. Prompt Shlpment is assured when these directions are followed. Panel Inside Dimensions Art. phone reception. Used with our Detector Two Size No. Each Step Amplifier it produces very excellent re- HEADSETS 16gli I Wide I Dea de- BARAWIK QUALITY sulte. A lee dal good work with crystal These headsets hate proven on rigid tests to be one of the 6x 7" M420 $2.48 on formica 7" 5 sit" 6tá" tector. Silk revered windings very beat en the market. The tone quality' is excellent with 10 " M422 2.75 finish wood work. 6x10 1k" 554" " tubes. Very fine- mahogany an unusual volume. Stilled workmen make there from only the 6x14" 534" 1334" 7" 14424 3.30 Mae size ex18 inches. Slider controls pri- The receiver eases are line polished M423 be treat selected materials. 7x14" 839" 1334" 7'r 3.60 mary, 12 point switch rut secondary. Can ear pieces. Fabric covered head 90426 3.90 nickel finish with polished black 7x18" .0340 17 55" 7r' toned very close. .Brass metal parts band comfortably and quickly fitted to the head. Supplied with 7x21" .6sá" 2034" 7" M422 4.20 value at our price. finish. A wonderful 5 -feed cord. These sets there designed to sell for much higher 9x14" Brh" 18%" 10" 14420 3.9,0 $6.39 our are a wonderful bargain. M430 4.40 M720 Pelee - prime than we ask, and at price 12x1.1" 1115" 13 sh'r 10" We guarantee that you will he pleased with them and agree 12x21" 1114" .2014" 10" 90432 5.25 salue by far yet offered. If they don't TUNING COIL that they are the hest SOLID GENUINE CONDENSITE Range up to 950 me suit you we will cheerfully return your money. term. Wound with ha: M770-2000 ohm $3.75 CELORON PANELS copper wire, machin Notice our very low prices on title line quality ER STANDARD BRAND HEADSETS grade 10 genuine solid abeet Condensate spared. Ends of ma- M754 Baldwin Type C with untversel jack M751 - -. 26, 2080 ohm $4.20 telnron la product with Mechanical, chemical hogany finished hard plat_ $12.00 easy slitting ratans nn pltuhert M752 Mental( a6, 20110 ultra...- 4.95 and electrical pmpertiee Ilke formica and wood. Two M755 Baldwin Type 17 melt 5.50 Substantial. edttn 4.20 iukelttei. Machines well without dripping. beaus ante, four binding poste. M764 Front. 2000 cord $5 75 Iligheat efficient. attractive. Length, 8% In. M766 Frost, 30110 ritin 4 95 W'on't warp. Waters roof. prechanicel M756 Red -Head, :1000 dim 5 78 strength. Attractive natural M722 Price $2.45 M758 Wrntern Electric, 2.200 °boa 9.50 Bungles, 2000 dim 7.15 and dielectric M768 polished black finish which an he sanded VARIOMETER and oiled for extra fine tenet:. 90410 -Completely assem- Panel \(," thick :1- 16" thick 'v" thick bled. price $2.69 TWO-WAY ROUND PLUG RADIO JACKS AND PL GS design and Sire Art Art -Art l'erfert In M397 Each $ 98 _ Finest grade leeks. Inches No. Price No- Price No. Price moat ruction. Accurate Takes ton of heed ee. Improved des i g n. paire 41x7 M450 91480 11470 $0.99 wood forms of genuine set terminale. Quick easy Beet materials. Phrre- AlKiä $0.50 solid mahogany. Correct Polished pior bronze springs. 6x1054 94451 .75 M461 1.1' M470 1.47 connections. M452 14462 1.55 61472 2.05 inductive ratios. Solid touted Fits any standard lark. Silver contact points. 6x14 1.05 beret. M458 1.20 M468 1.8 91478 2.40 hated wi red final. Positive Nickel /leash. Mount on panels 7,4 to 34 in. 7x14 reattach'. highest et8- 'x18 14453 1.55 M463 2.3 M473 3.10 thick. M467 M477 elenn-. A real bargain. ENCLOSED DETECTOR 43e 7x:1 M457 1.78 2.6; 3.60 1 90390 Open chat. Earl, 6145e M464 M474 3.10 M411 -Net assembled nor of the finest crystal Closed It. 49e 9x14 1.60 2 3 One 12x14 11455 2.IC 90465 3.1 11475 4.15 wound but all parts com- detectors on the market. -tecks (tit39190392 Two circuit 00e plete except wire. includ- t2x21 11456 3.15 M466 4.6 4476 6.20 Sulersensltive :alerts aye - Only i M393 Single clrcumt filament ant 69e ing winding term. $1.49 lei enclosed in heavy glass 1 90394 Two circuit filament cost 85v ETCHED METAL NAME PLATES shield. Quick. positive ad- M395 Plug. Large spur with set screw, fret Mule of brans. Situer platen V ARiO-COUPLER justment. Reese parts pol- attarbltg cord. Euch 49e o charadma and border on N415 Price, completely ished nickel flrdnh. -- black background. All Plates assembled $2.45 M730 Each $1.18 are I Inch long and ?4 tech with this tense mutter COMPETITOR JACK AND PLUG wide. except "INCREASE CI'RRENT" whirl) etc quarter circle inch over all, and and two vaiumuters, to- GALENA DETECTOR Well inerte. durable, smooth working. Inter- 1% gether with the necessary Jades and Plugs "ON" '.OFF" whirl. are % teal forut. At- Eaoy fine adjustment. Crys- changeable with any standard taching holes pierced. other parts, a highly effi- tal mounted In cup. Mould- Folder connections. Nickel finleltel metal cient tuning set can be 90503 Per Dozen 35e ed base and knob. Brace Parts. Not less than ilnzen made. Easily mounted on Erich 27e me assented Bold. Sled() parts polished nickel finish. M387 Open circuit jack. t, anted panel. No base included. Two lack. Each 35e an fow'': An unequaled salire. M388 eircuit Plate Variameter Secondary Aerial Primary wlning nit for- 91732 Each 59e M389 Standard plug. Each 35e mica tube. Inductively Grid Vnriameter Primary Ground roupled for 1811 to tihtl meters. Multiple tape Vacuum Tickler Phones hermit tine tuning. DETECTOR CRYSTALS CARE- Primary Condenser leud'e Coil Input BINDING POSTS Secondary Condenser Coupling Output M416 Not aseentitled nor wound hut all parts FULLY TESTED limes, notified nickel finish. Increase Current Parallel 0e ,- oio!ete except e ire. Price $1.18 M736 Gallen*, Arliegitm tested, per piece.19e Washer and 6-32 in. screw (to right) Series O8 M417 Rotor hall only. Farb 29e 91739 Sitian, Arlington per in. Increase Current Detector Ist M408 Bakelite stator tube only. Fare 35e tossed, piece. l9e extending ?4 Step 91735 Buzzer tested, Galena, per piece.. 9t M370 Large size --barrel and (to left) A Battery 2nd Step 91737 Buzzer tested. Sillenn. per pieee.. 9e Penh rya In. long, dozen ..854 B Battery 3rd Step MOULDED VARIOMETER M372 Smaller size -- hat eel (Blank -takes pencil er pen marta.) Polished black DETECTOR PART! and knob 9-16 in, long, S moulded rotor and dw.en. 70e ELECTRIC SOLDERING IRON stator tonne. Maxi- M725 Price Net .32e M374 Large size with rom- mum inductance with All mete' piarte for ta,nttlon Irnoh, dozen 50e greatest efficiency and e-ittel detector. No 14376 Large size with hole minimum distributed hsse included. Easily for plume tip tic Wire, dozen - 80e rapaelle. A high grade assembled. Polished m-. nickel finish. 90378 Small size with hole for phone etr duraIt le instrument dozen 35e that will make up wire, Into a set you will BAKELITE DIAL AND KNOB M957 Price $5 75 he proud of and toll) SWITCH CONTACT POINTS Especally adatuteal to radio work. WI11 enable get the best result.. Moulded of genuine bakelire, polished you to du neat clean work quirkly. Simply el - Ware lengthen [h IRO to flulale Fluted eludeo R4árBraila polished mirkrl els it All have tech in any lightg it tor, k et 1t0 1-0 col' s L`um- s¡ Floen 000 meters, 4 in. square, 1 ?4 In. Lick. engraved gale with aaarp Vicar In. lallt size 6-32 screws anti two nuts. elate with Dix {tot mol and attaching plug. 411 prices the same. Renew*hle Bolder M412 Pelee 'wheeling mounting hearken $4.25 graduations and figures in contrast- point. Will levi a Ilfetbnc ing elite enamel. This fa the Dezen Ilk Hundred $1.05 for ordinary houe or light shop work. A finest quality dial aert latob 1n Order by Article Number. wonderful value at the price. MOULDED VARIO -COUPLER in. lItgh a very attractive pattern. Two M360 Head. bá In.; Dian. 4- MAGNET This 41:112 Henri, :1-10 ln. ; Dietm. 54 in. High WIRE ampler la draignet! to ,--- Inch cannot be supplied for sh Inch lneulated copper wire. Beet meek Ndth the above earl- 14363 Head, 3.16 in. ;Diem. I.1n In.fligir quality even shaft. drawn wire, one piece to a nmeter. The stator end Solder Lugs to Fit Centaet Petits stool. friers 9091$ 2 In. Dann. for 3-16 In. shaft. Ea.40e Also for connecting wire. to hind- punted are for R ne. spools. rotor forms are of polished 3 3-16 in. shaft. Ea .49e 1119C2 in. Plam, for the onats etc. Double Cotten' Elle meted Green black moulded compoeitIon. ." % in, '! 91903 In. Plant. tar shaft. Ea...490 12e Hundred 60e Primary has seven tape to h4 M365 Dezen - Covered Iiteu tat ion SIN Covered 91916 4 In. Diatu. for - in. ',hart, Ea...74e enable finest tuning. Wave Nember 94990 Nennter M992 Number 90991 length range 180 to 650 meters. Fitted with panel mounting bracket. ONE-PIECE DIAL AND KNOB SWITCH LEVERS Gauge frire Gauge Price Gauge Price 91419 Price $3.95 18 50e 20 45e 20 $0.78 Moulded in one were . of Moulded composition knob. 20 60e 22 56e 22 polished black compouitttr Fxlarsol metal parta polished 22 75e 24 61e 24 1.05 180" VARIO -COUPLER with dean pia,n engraved nico el !inlet. Fitted with panel 24 85e128 65e 2e 1.18 91418 frire $2.89 scale and numerals in con- hushing, spring and two set 26 95e!30 70e 30 1.70 Our price shows you s trasting white enamel. Ribbed Ms A high grade switch. 2.05 big wring. An hletru- 28 $1.15!32 79,e 32 knob to fit the hand. An 91382 1% in. Rattle "l 30 1.65!38 98e'38 2.75 ment of higghens quality. ttreetive neat pattern. 90381 I'4 in. Itadius . 19e The must efficient type of 19e Eáeh 91900 214 In. Diann. for 3-76 in. shaft. Ea. 90380 1 in. Radius STRANDED ANTENNA WIRE

Chi neo s Original 102 South Radle Sup ply Hause ILL. THE BARAWIK CO. Becere ei Imitators Canai Street CHICAGO, 1112 Science and Invention for March. 1923 KNOW WHO IS SENDING

Get twice the pleasure and usefulness out of your receiving set. Look up the name and location of any ship or land station whose messages you pick up-learn the name and address of that amateur whose sending set you just heard. 4th Edition of the CONSOLIDATED RADIO CALL BOOK In a new large size -280 pages 88 more valu- able pages than the 3rd Edition and featuring 7 Two -Color Radio Maps Five of them are Continental Maps showing all stations throughout the world hand- ling commercial traffic, with their calls; one showing the amateur radio districts of the United States and the principal radiophone broadcasting stations with their calls; and a map of the United States Weather Forecast Zones. Seven wonderful, two- color radio maps with a wealth of information that will give you a great deal of pleasure and knowledge. Every Amateur Call in the U. S. and Canada Is Listed Besides- Other Valuable Information Contained in This New Book All Amateur Radio Calls of the United States and And every vessel and land station in Canada; Every Vessel, Coast Station, and Radio -Compass the world Station in the World; Radiophone Brosßcasting Stations of the is represented and listed alphabetically, according both United States; Every High -Power Station in the World; Special as to name of vessel or land station, and to call letters. Land Stations of the United States; Time Signals, Hydrographie and Weather Reports of the United The Consolidated Radio Call Book is the States and Principal Foreign Countries; International only book in print officially listing all the Abbreviations; Assignment of International Calls; Press Radio calls Schedules; Radiogram Rates; . Cable Rates; as issued by the Bureau of International Morse Code and Continental Signals; Commerce. And the New Radiophone and Complete General Information covering Distress Calls, International Safety Signal, Use of 800 -Meter Broadcast Section is particularly complete Wave Length. Amendments and Changes in Various and gives all available information con- Governmental Regulations, How to Determine Charges on Radiograms, Free Medical Advice by cerning calls, wave lengths, . PROGRAMS, Radio to Vessels, and much other u.eful information. etc. The third edition of 10,000 copies was exhausted in two weeks. The fourth edition is selling just as quickly. Don't wait until it is all gone. Order at once, either direct from us or from your favorite dealer. Published by Consolidated Radio Call Book Co., Inc. 96-98 Park Place, New York City. Great 40 -page Supplement FREE to all who have the 4th Edition Call Book As a special service to the readers of the Fourth Edition of the Radio Call Book, we have printed, at great expense, a 40 -page supplement containing the latest amateur radio calls of both the United States and Canada, and other ;calls issued very recently. It is absolutely free to all those who write for it, provided you have bought a copy of the fourth edition of the Consolidated Radio Call Book. This wonderful supplement brings the call book up to the very last moment and on account of the; many changes that have taken place and which are fully covered by this supplement, every radio amateur or professional is urged to send for his free copy of this supplement today. 1113 Science and Itivcntion for March, 1923 eI,I,,,,,,,,e,,,aaa,nnn.,aM,e,,,e,,,,,,,ana,,,,,,,,,,,,nnennnn1,1,,,,,,,,,na 1ne,,,n The Amateur Magiicii n By JOSEPH H. KRAUS (Continued from page 1069)

1smuuuc11111o11111m1111111111111111111111111111111111111111111111s111111111111111111111nos1,1n,uw11n11111m1111111r. Near the base of the candlestick -holder, a tin pill-box was located, the cover of which had been cut open leaving only the rim and the same was used to clamp a rubber dia- phragm to the rest of the box. Another pipe leading from the bottom of this pill -box, led to a small funnel, having at its mouth a diameter of approximately 1% inches. Close up against the base was a single stroke bell, the gong of which had been removed, and its hammer bent upwardly so that when the bell was operated the hammer would strike the rubber diaphragm. The circuit to the bell was completed by means of two wire brushes resembling pieces of wire hair brush. These were secured to a base of fibre, and the latter screwed to the candle- stick base. The table -top itself did not disclose any openings, being covered with cloth, but Hargrave took particular care in placing his candlestock down upon the table. When he removed it again, he showed me that the -table also contained two wire brushes, which projected upward, and when the candlestick was placed down upon the table, the brushes interlocked, making, as he said, a more perfect contact that the plate and point method he had heretofore used. Near the center of the candlestick -holder, directly under the funnel end of the small copper tube, a hole was drilled through the table -top which admitted a % inch tube. This tube did not pass through the table- cloth or cover, consequently, the opening re- mained concealed. The. tube was connected to the illuminating gas supply line, which furnished the gas for the light, seen emana- ting from the candles. The gas itself burned with a yellow flame much like that of a tal- low candle. "It is evident," Hargrave continued, "that whenever the single stroke bell is energized, it strikes the rubber tambour. This causes box, the gas contained within the metallic Dept. G, 826 Drexel Avenue to be compressed, which, finding its path of School and 58th Street, Chicago. upwardly direction, American least resistance is in an full information on the subject checked and how you will help me win success causes the flame to rise considerably above Send me normal. The flame then drops down, and Architect Electrical Engineer Steam Engineer Building Contractor Electric Light and Power Foremanship at a word of command, it can be made to Automobile Engineer General Education Sanitary Engineer fall below normal. Automobile Repairman Vocational Guidance Surveyor (8t Mapping) did I not smell any gas when Civil Engineer Business Law Engineer "But why Structural Engineer Lawyer Telephone you extinguished the light?" I interrogated. Business Manager Machine Shop Practice Telegraph Engineer simple reason," was Hargrave's Cert. Public Accountant Photoplay Writer High School Graduate "For the Engineer Fire Insurance Expert I precaution to open Accountant and Auditor Mechanical reply, "that took the Bookkeeper Shop Superintendent Wireless Radio one of the windows slightly. The amount of Draftsman and Designer Employment Manager Undecided gas passing from one of the candlesticks is very small indeed, and it would take quite some time before the odor would have made Name.._..--- -.._._...... _.. you aware of the fact that the candles operated on illuminating gas. By insuring Address - ..... _...._.._...... a proper circulation, you would probably - never realize that fact. Naturally I get a sort of Bunsen burner effect, except that the air is not forced upward with the gas. The lack of air supply produces the yellow flame. When my assistant, who operates the keys controlling the relative lights, presses any of MakeYour&keMMIIIMMM the switches, the hammer of the bell con- You can produce wonderful, soft, sweet music tained within the base, strikes the rubber from a common carpenter's saw with a violin diaphragm of the tambour. This causes the bow or soft hammer, if you know how. No musical ability required-you need flame to lengthen. When the key is re- a Motorcycle not know one note from another. leased, and the circuit opened, the hammer You, too, can do it easy and Easy to Learn inu a3 Weeks ! 1 absolutely Dun rentea to flies backward and the flame drops below in 90 minutes time --no special tools teach you to sic1popular le or knowledge required. Your old bike and the Shaw weeks. musk wiwithin threet s the normal point." Motor Attachment give you a speedy, dependable weeks. 1 gist you the secretsw motorcycle a small cost. 25i H.P. motor, Runs of ec a accede as a sew "As to the rapid calculation of figures, at I Guarded carefully, that from 4 to 40 miles hour! musician,sl iais ruducn an I i fref:E "Tea Muelcal Sew." is very simply accomplished. My Japanese siICYCLErsANY 9nilucceo whatee us a The Shaw Attachment B charge temper 1 fail.a. valet, who listens to your questions by means Easy to control, pleasing to ride, economical to op- FREE --a specialeBow tempered erate. Thousands in daily Saw Saw Bow,_ Soft -Hammerhemmer freeThis of a telephone receiver which connects to a with Course Inctimple use. Ironclad guarantee, Course Is abort, simple end easy.each. microphone placed in his room, takes down WRITE full a^ Only three Softenlessons, one Information about months oYtedió us practice. the numbers on a comptometer. By the time wonderful At- MAKE BIG ig ammo tachment d the friend,n Dewing rte dances, LoaLodge you have figured up the result, he has al- Shaw Soper -Motor. Church Entertainment Writs blerel, which e todday for information "Mow to Play ready completed the operation, and the ans- also manufacture. Saw" --sent free. is being by SHAW MFO.00. C. J. MUSSEML. 322 Mack Bldg., Ft. Atkinson, Wis. wer transmitted means of the eale,ksq,[a.0UL46 light flashes. d 1114 Science and Invention for March, 1923

INVENTORS, ATTENTION Th Sleep EIlIlunIln tor By H. GERNSBACK THE PATENT OFFICE (Continued from page 1062) is 70,000 cases behind and matters getting worse. and asked them if they would care to under- fresh air. This is done almost uncon- go an experiment to do away with sleep The patent office has made over sciously. It simply means that the body 8/ altogether, for a number of days. He found needed oxygen in order to supply the nerve million dollars for the government out that keeping awake for the first twenty- centers with their needed regeneration. and there is no valid excuse why in- four hours was the hardest task, and the Then, also, a good many night workers men ventions which mean so much to under observation became very haggard who must, perforce, stay awake, often take an looked extremely fatigued. After the to harmless drugs, coffee being one of them. NATIONAL PROSPERITY first sleepless night, the second and the third The caffeine seems to stimulate the nerve wei a not so arduous, and mark the forward progressive and the work went on centers and other centers to again restore the without so much personal discomfort. At balance and the work can go on again for spirit in our economic and industrial the end of the experiment it was found that a number of hours. life SHOULD NOT BE KEPT UP three or four entirely sleepless nights could The idea which the writer advances in the TO THE HOUR. be compensated for by eight or ten hours following lines has to do with the artificial sleep, without the subject being any the regeneration of the nerve centers, the blood THE WORLD OF INVENTION worse for the experience. vessels, and other centers that have become When we reflect fatigued or a Live Progressive Magazine devoted that if the life of the worn out. The idea in its average human being is 50 to 60 years, one- entirety is simple: to the interests of the inventor and the half of this is actually wasted in sleep; then It shows us what will be donc' in the official organ of the if we multiply this by the entire human future. Our text illustration as well as that race, we discover a waste that is appalling in on our front cover, convey NATIONAL the idea, which INSTITUTE OF INVENTORS its entirety. Suppose we could do away is simple enough. No scientist will deny a co-operative society of over 3,500 with sleep altogether! Suppose we could that the more we fight sleep the higher our inventors is offering $200 in prizes for lead our regular lives without sleep at all! blood pressure will go. Finally, during sleep, Would this not suggestions relative to relief from the be a wonderful boon to the the blood pressure comes down. If, then, race? Would it not increase our activities high blood pressure is one of the reasons patent office conditions so detrimental why and also increase our lives by just 100 per we feel the necessity of sleep, we have to the inventors' interest. cent? It is a truly fascinating project, and means to overcome this electrically, by means is not half as improbable as it would seem of D'Arsonval high frequency currents. at first. These, as is well known, tend to drive down Write for full particulart There are, of course, many ways in which the blood pressure quickly, and with lasting we can do away temporarily with sleep. results. Authors and writers as well as students, On our front cover we see the City Editor WORLD OF INVENTION know Well that when they become drowsy dictating his work at 3 o'clock in the morn- S E. 14th Street, New York City, N. Y. at about 11 or 12 o'clock at night, the most ing. His body is surrounded by a D'Arson- unfailing expedient to overcome sleepiness val spiral, which keeps his blood pressure is to step to the open window and draw in down as long as he works. We also see on the wall oxygen tanks which give the room atmosphere a higher oxygen value, which value, however, is not high enough to do any damage, just enough to stimulate the CLÂREFCE AÂ ,CiEPT01CE ER worker. We also see that the chair is upheld by PATENT AT QRNEY an insulated metallic sheet into which are 1 fed other high frequency currents, which R LOWERED .IN UNITED STATES PATENT OFFICE: currents serve the purpose of stimulating MEMBER OF THE BAR OF the nerve cells. There are a number of such currents that can be used. It is the current SUPREME COURT OF UNITED STATES COURT OF APPEALS DISTRICTOFCOLUMBIA that gives a sort of very slight twitching SUPREME COURT DI STRICT OFcOLUMBIA UNITED STATES COURT OF CLAIMS action to the nerve centers, the subject being hardly aware of the process. There are a PRACTICE CONFIN ED TO PATENTS AN D TRADE MARKS number of machines at our disposal today rOMMill11111fflell. that do these very things, as they are enum- erated, and it is only a matter of experi- menting find EXPfRiENU: to out the right combination. ISERVI Under the influence of these two sets of Protect Your Ideas currents, and the oxygenated air, it should Any new article, machine, design or improvement thereof, or any new be possible combination of parts or improvements in any known article which to eliminate sleep for any length increases its efficiency or usefulness, may be patented, if it involves of time invention. without the subject feeling the worse IF for it, either during the treatment or after- YOU HAVE ANY NEW IDEAS wards. which you feel are useful, practical and novel, take prompt action toward protecting your rights. If you have invented any new As we mentioned before, sleep is not of machine, or new combination of parts or improvement, or new process or design, a real necessity as long as we can do away SEND DRAWING, MODEL OR DESCRIPTION with its causes in such a way that the sub- of it for information as to procedure to secure protection. ject under treatment experiences no ill ef- WRITE TODAY FOR BLANK FORM f ects. "Evidence of Conception" In our text illustration we have shown to be returned to me with drawing, description or model of your a modern newspaper office, with a idea. Promptly upon receipt by me of your idea I will write you fully Sleep as to procedure and costs. Eliminator. It is realized that in a news- NO CHARGE FOR THE ABOVE INFORMATION paper office somebody must work during the All communications are held in strict confidence. My personal, care- night and sleep during the day. Such a ful and thorough attention is given to each case. I offer you efficient, reliable and prompt service-based upon practical experience. Highes! thing, in a few hundred years from now, references. will probably be eliminated entirely by Write to -day for free book "Flow to Obtain a Patent." This book will give you valuable information, and it may save you much time means similar to the one suggested. and effort. Send for it NOW. In this newspaper office we have the My practice is devoted exclusively to United States and foreign D'Arsonval patents and trade marks. Very probably I can help you. Write today. coil which is to reduce the blood CLARENCE A. O'BRIEN, Registered Patent Attorney pressure, mounted against the walls of the 1900 Southern Building Washington; D. C. office, so that every worker gets the benefit. The wires are led CLARENCE A. O'BRIEN, 1900 Southern Bldg, along the walls, as clearly Patent Attorney, Washington, D. C. shown, and are energized by the machine Please send me your free booklet "How to shown at the left. Obtain a Patent," and blank form "Evidence of The oxygen tanks are in Conception" without any obligation on my part. evidence, as are the glass insulator platforms which insulate the workers from the floor, Name while the machine is in operation and while Address the subjects are being electrified. (WRITE CLEARLY) If one desires to step off his chair, he (Continued on- page 1137) Science and Invention for March, 1923 U.S. PAT NTS III" 111111' e- CE FOR ¡BEND FOIJ,il Edited by Don't Lose Your Rights nu-aus your invention to any- jeseph Before disclosing of one send for blank form "Evidence signed and witnessed. inventors and particularly Conception" to be In this Department we publish such matter as is of interest to form together with printed in- Patent Phases. Regular inquiries addressed to A sample to those who are in doubt as to certain here structions will show you just how to work answered by mail free of charge. Such inquiries are published "Patent Advice" cannot be we make it a rule not up your evidence and establish your rights for the benefit of all readers. If the idea is thought to be of importance, As as far as it is possible to do so. before filing application for patent. to divulge all details, in order to protect the inventor represents made for each question. registered patent attorneys we be desired by mail a nominal charge of $1.00 is U. S. Should advice side of sheet should be written on. hundreds of inventors all over the Sketches and descriptions must be clear and explicit. Only one of inven- name and address and Canada in the advancement mailing your letter to this department, see to it that your of fees will be found NOTE:-Before are returned to us because either the tions. Our schedule are upon the letter and envelope as well. Many letters The form "Evidence of Con- is incorrectly given. reasonable. name of the inquirer or his address ception" sample, instructions relating to obtaining of patent and schedule of fees RECORD Ask for them. --a po-t AUTO TRANSMISSION LOCK PHONOGRAPH sent upon request. Newburyport, Mass., card will do. F. C. Mason, Leicester, England, asks (697) L. W. Mulvey, (692) a system of making a he patent a lock for automobiles, claims to have originated whether should phonographic record play just twice as much engaging in the transmission. He sends in a two description. music by inserting another groove between very good drawing and in which groove the music is A. In the United States at the present time adjacent grooves, to be recorded. He inquires as to the patent- it is not desirable to employ a lock which will BLDG., of an ability of the idea. 255 OUILAY engage either the rear wheels or the gears not doubt that you can automobile. A. Although we do WASHINGTON, D. C. a patent on a double -track phonograph Such a lock increases the cost of insurance secure "Originators of form Evidence of Conception" we see absolutely no advantage in such a upon a car considerably, because of the fact that record, once it is locked. record. The music grooves in modern records the car cannot be moved when Any attempt to make Many insurance brokers here insist that a car be are very close together. of at least 200 them closer will break through the side walls. permitted to move for a distance an additional enable firemen to remove cars Consequently there is no room for feet. This is to those now found, and there is no a burning garage, or to shift the cars should groove between from way you could increase the amount of they be blocking a portion of the street to which in which music by adding another groove, as at the same fire apparatus must move in order to successfully now found flames occurring in that vicinity. time you eliminate every other groove battle with any a sapphire point in- A car rigidly locked, as you describe, would upon the record. By using away, which towing would stead of a steel needle the record grooves could. have to be towed is one way of in- destroy the tires and perhaps even cripple the be put closer together. This creasing the surface area of a record. machine. which we will not Locks of this nature would be very difficult There is another method cars, as changes in the mention at the present time because the inventor TO THE MAN WITH to adjust to the standard he has requested us to transmission gear box would have to be effected, is patenting the same and which changes are, of course, costly. Conse- keep the idea secret. AN IDEA quently, we are of the opinion that your device I offer a comprehensive, ex- will not meet with very great favor, and therefore PROTECTOR AND TYPEWRITER for to patent the same. CHECK perienced, efficient service we advise against attempting CLOCK his prompt, legal protection and OUR COMMENT REQUESTED (698) F. C. McCleish, Memphis, Tenn., sug- the development of his proposi- P. McCarty, Electra, Texas, asks gests that checks be made like money orders with (693) W. idea is a lock tion. comment on a perpetual motion ma- stubs left on the end. His second Send sketch, or model and descrip- us if we will requests our opinion. chine. for typewriters. He tion, for advice as to cost, search be glad indeed to comment A. With reference to your check protector, we prior United States patents, A. Yes. We shall not pos- through of a perpetual motion machine, would advise that such a system could etc. Preliminary advice gladly fur - upon your theory idea itself being very old. not operate. sibly be patented, the i shed charge. and tell you why your device will be without necessary but we would suggest that Check protectors of this nature would not only My experience and familiarity with No model is necessitate an in- make your description clear and your draw difficult to handle, but would various arts, frequently enable me to you a mass of added paper. ings to conform with the description. creased cost in printing and accurately advise clients as to prob- Imagine having a check made out for say $9,421.64. able patentability before they go to COMBINATION This would be obviously impossible with a check any expense. CIGARETTE-MATCH in communication, N. Y., asks protector as described your Booklet of valuable information (694) Wallace More, Madalin, were made of such a large size as to disclosing idea for a com- unless it and form for properly whether he should work upon an take in all the figures. your idea, free on request. Write bination match and cigarette. the amount match and The modern check protector prints today. A. Your idea of a combination right on the check, and in fact perforates the cigarette is not new, and to be perfectly frank, is practically RICHARD B. OWEN, Patent Lawyer fact, we check itself by such printing. It worthless. To convince you of this non-raisable, speedy in operation, and inexpensive. 164 Owen Building, Washington, D. C. would suggest that you cut off the end of a idea, we would like 2276-8 Woolworth Bldg., New York City protrudes. Push With regard to your second match, so that merely the tip to ask you why anyone should care to lock a this tip into the cigarette, and strike this cigarette open in the cigarette typewriter. Typewriters are not left on a box. Nine chances out of ten, offices where undesirable persons may wander. will be broken. At the tenth attempt you may light the same, and then as you try to take one puff of smoke, find your mouth full of sulphur fumes. We also believe that the idea is not patentable, having been fully covered some twenty years ago. TRADE -MARKS AN USE FOR CARBORUNDUM (695) Kenneth Moehrl, Marshalltown, Iowa, COPYRIDGHTS desired to fit a peculiarly shaped carborundum pATENTS stone into a handle to be used for a specified write the Before disclosing an invention,ion the inventor should purpose. He asks whether he should patent 0 be Idea. for our blank form, "RECORD OF INVENTION." This should A. Carborundum "stones" of the type you de- or sketch scribed in your recent communication, are neither signed and witnessed and if returned to us together with model new, novel, or unusual. If you will write to any we will give our opinion as to its of the branches of the carborundum concern, you and description of the invention will find that stones of your size and thickness patentable nature. Radio and Electrical cases a specialty. are obtainable. Merely fitting a handle to them and specifying Our illustrated Guide Book, "HOW TO OBTAIN A PATENT," the device, does not constitute a claim Reasonable Terms a use for Highestg References Prompt Attention tor a patent, and consequently; we would suggest sent Free on request. 11,11111.mm. 11111 111 11111 in the matter. sa 11111111111111111111111 11111111111111111111111111111111111 FREE COUPON no further action Attorneys CREAM WHIPPER VICTOR J. EVANS & CO., Patent Philadelphia Offices: San Francisco Offices: Maxian, Bellaire, Ohio, submits a Chicago Offices: Pittsburgh Offices: (696) John 714-715 1 cher*'. Rldg. Hobart Bldg. sketch for a cream whipper and requests our 1114 Tacoma Bldg. 514 Empire Bldg. opinion. New York Offices: 1001 Woolworth Bldg. A. We see nothing unusually novel in your MAIN OFFICES: 779 NINTH, WASHINGTON, D. C. merely taken one of "cream whipper." You have Address the old style whipping machines and fitted it with Name a gear and motor drive. This constitutes no claim ter a patent whatever. 1116 Science and Invention for March, 1923 They are generally locked with the desk itself. For transportation, a simple and far more ef. fective system is employed. Two plates are screwed on the typewriter which hold the car- riage rigidly in place, far more rigidly than any lock; and last but not least, unless the lock is Tes[Yo very bulky and heavy, it is very a easy matter indeed to snip it free and sever its connections CAN YOU with the typewriter. think of a simple, practical idea that will fill one of the many re- Changing Our Numerical System quests we have on file for new inven- Englis tions? It may mean a fortune for you. (699) A. Aranza, Fairhope, Ala., writes: Thousands of things are needed RIGHT There is a good and bad side to everything, and Now. YOUR brains can help. Send to- Seel tMistakesrouM& so it seems for our new amazing as It rosy seem, actual tests provo to be with our numerical system. This day great book-"inven- that the average person is only 61 per cent. is founded on ten, and ten in my opinion is not tions and Trade Marks, Their efficient in the essential points of English. the best and most economical number, nine is Protection and Exploitation" Most people realize that they may be making worse than ten, but eight is much better, and and learn more about making mistakes, but de not know what they are taken all together money from ideas than you ever sr how often they are made. number sixteen is probably the Sherwin Cody, best. So I have formed my knew before. It tells many America's foremost teacher of practical Eng- numerals on the things are lish, has at last solved the problem of bow sixteen system, because sixteen has a large di- that wanted, you can test your knowledge of English and mension and is easier to figure and divide. For too. A postal will de- see just where you stand-you can instantly example, take our discover your mistakes dollar- This has a hundred it free. i and correct them forever. cents; a half dollar fifty cents; a quarter, twenty. SHERWIN CODY'S GREAT INVENTION five cents; an eighth of a dollar, twelve and a In new it amazingly half cents; and on further division yiosu we find that for learnhcorrcorrect Englishhasrapidly. has! discardedeasy our money is in all the methods fractions. In my system, how- old which made English so hard to learn. ever, we can divide the dollar in half No time la wasted. All your efforts are concentrated on quarter, acquiring a perfect command eights, sixteenths, and even further, without of English-eliminating your ing to fractions. com- mistakes, and substituting for them the correct way. Only I have no doubt but that this We flelD Ow dieing. PATENTS 15 minutes a day, In your spare time, la all you need to system is superior to the modern system, and Without charge. to get learn English this wonderful, new way. would like your advice regarding the same. the dollars out of their ADVERTISED E, T GET THIS TEST A. We do not think very much Ideas-having facliltle9 FRE of your system none others possess. AND BOOK-FREE of arranging numbers, so that they will be divisible For SALE FREE Mr. Cody has prepared a short, interesting, 15 -minute by which tells test sixteenths. It is true that we have dollars, you, privately, just where you stand in your half dollars, quarters, Advice free. knowledge of good English. If you are better than the but why should our system in INVENTION And average, it will give you added confidence cut the dollar in half, and then cut Don't delay-get the in your ability; the half dollar et once. If you are deficient you surely want to know it. Write in half again: Today the decimal system is well book MANUFACTURING today for this test-it is free. We will also send you our established, and if the money and weights and new free book, "How to Speak and Write Masterly Eng- measures systems SUPPLEMENT. lish," which explains would follow the decimal sys- " AMERICAN in greater detail how Mr. Cody's tem, we would have great invention gives you a masterly command of something really worth while. in only 15 English In this system INDUSTRIES, Published for minutes a day. No matter what you may be- it is easy to multiply, subtract, INC. the lieve you know about correct English, make divide, raise to any power, and man with an Idea. test and learn this FREE extract any root. actually what you know! Write for it today. All we have to do is to add a few zeros or sub- 225 Patent Dept., Bend for free sample SHERWIN CODY SCHOOL OF ENGLISH tract them. The dollar now contains ten copy. One year'seub- 423 dimes, WASHINGTON, D. C. ecrlptlon 50e. SEARLE BUILDING ROCHESTER, N. Y, and each dime ten cents, each cent ten mills, the non -decimal divisions being the nickel, the quarter, You, Tao, Can Play the and the half dollar. Inasmuch as the world is em- ploying the weight and measures scale on a ten HAWAIIAN.GUITAR division plan, with the exception of the English speaking countries, who in scientific calculations ATENTS Just as the Nátives Do- also employ this system, we believe that there is It you have very little hope an Invention and desire to secure e for your suggestion. The centi- Patent, send for our Free Guide Book, HOW TO After Your FIRST LESSON meter, gram, second system is going to become the GET YOUR PATENT. Tells our Terms, Methods. standard. pto. Send model or sketch and description for our noir". You Will Play "ALOHA". or Its patentable nature. We Guarantee That- Our method is so simple, interesting RANDOLPH & CO. and appealing that you begin in your first lesson to learn the famous Ha- ! Dept. 172 Washington, D. C. waiian Folk Song "ALOHA". Think eerflmentaI how happy you will be when you surprise your friends by playing the fascinating Hawaiian Guitar EIlec42-®©Che á2tfy just as the natives do! IPA-T ENT S By RAYMOND Only Four Motions- B. WAILES Hand Books on Patents, Trade Marks, etc., sent free. Our 77 yearº of and You Master Them Quickly I experience, efficient service, nd fair dealing as Ins few minutes you fullest value and protection to the applicant. The piece acquire the four motions necessary to play any (Continued from page 1074) Scientific American should be read by all inventor.. -after that a short period of practice and you this weirdly sweet music- Complete will have mastered course of 62 lessons includes race 11111111 lllll MUNN & beautiful Hawaiian i CO., f!t Woolworth Building, New York Guitar, necessary picks, steel bar, etc. No extras. nnnmunuonmmaaiu1. Tower Bldg., Chicago, III. 611 llama Bldg., Cleveland, O. No Previous Musical Knowledge Necessary S.ientific American Bldg., Washington, If you never rend a D. C. musical note in your ifY haven't even the acetate or sugar of lead. A copper Hobart Bldg., 682 Market St., San Franctaco, Cal. slightest knowledge of music we can quickly and Po plate, cut toRi thin Wonderfully Instrument. itively teach you to er popular Don t he Suet a "hates any design such as a star, cross, wen you can easily be the center of intcrrel among your friends. etc., is Just Mail a Post Card for Details placed above the iron plate and current of our remarkable FREE Hawaiian Guitar Offer -- passed, using copper MR. INVENTOR simply write: 'l am interested" --but do as the cathode. The it tad« rings formed are WE ran develop that IDEA and build that working, Address very colorful. MODEL for you. Consult us-with our staff of expert First Hawaiian Conservatory FREE engineers, and thoroughly equipped experimental machine PRODUCTION OF LIGHT BY shops, we can develop any invention of Music, Inc. A Beautiful' ELECTROLYSIS proposition, Into a commercial Special rranoe- Desk whether mechanical. electrical or automotive tafari,,.vaa;f 40 --233 dway .Hawaiian An -simplify and perfect It, and MAKE IT WORK: (Woolworth Bldg.' electrolytic cell which produces cold Designing, building and testing Hawaiian New York labor gasoline motors a specialty. Experfi Guitar. City Guitar light, i.e., light without heat, saving machinery. Mechanical drawings made when a current fromóautomatic sketches or specifications. All bushman confidential and absue is passed through it has recently been de- lute secrecy guaranteed. vised. The cell is shown in figure 4. ELK MFG. CO., Inc. It con- 192G Broadway New Tork INVENTORS! sists of a glass vessel containing two elec- Patents procured. Trademarks trodes registered, prompt and an electrolyte. Electrode 1 can personal services, fees reasonable- Request free be either carbon or aluminum, "Inventor's Guide," giving while elec- detailed information. trode 2, the anode, is made of an alloy of FRANKLIN H. HOUGH, Inc, aluminum and manganese or aluminum, man- PATENTS ganese and copper. BOOKLET FREE HIGHEST 520 Washington Loan & Trust Bldg., The electrolyte con- PROMPTNESS REFERENCES sists of a solution ASSURED BEST RESULTS WASHINGTON, D. C. of citric acid or a solution Send drawing or model for examination of ammonium citrate, borate or bitartrate. and report as to patentability. When a direct current WATSON E. COLEMAN, Patent Lawyer passes through the 624 F ea oneoi w' solution via the electrodes, Street N. W., Washington, D. C. eat (nema .c America we a film of alumi give inventors num hydroxide is PATENTS consistent at loweat deposited on the positive service noted for results, evidenced electrode. This is Patents by many well known because the hydroxyl radi- of extraordinary value. Book, Patent-Sertae, ree. cal !stay& Lacey F St., Wash.. OH, of water, is negatively charged and D.C. Estab, 3 ií69. passes PATENTS to the positive pole, is neutralized of PROTECT its charge and combines YOUR INVENTION TODAY with the aluminum Write for FREE illustrated Patent Book. metal to form aluminum hydroxide, Radio -Electrical, Chemical and Mechan- PATENTS Al (OH)3, This film of hydroxide will ical Experts; Over 25 years' experience. Send for free book. Contains valuable information then glow on continuous passage Prompt, Efficient Service, Write for inventors. Send sketch of your of the cur- today. Free invention for rent, the whole constituting A. M. WILSON, Inc. Opinion of its patentable nature. Prompt an electrolytic 311-17 VICTOR service. (Twenty years' experience). cell producing light radiations. BLDG. WASHINGTON, D. C. TALBERT & TALBERT Alternating current can also be used with 441 Talbert Bldg. Washington, D. C. the cell, but electrodes of aluminum alloyed C, L. PA R K E R Formerly with copper and manganese Member Ex- PATENTS have to be used, PATENTS amining Corps, 9. SECURED forming them first with a direc. current so Patent Oiflces. Prompt service. Avoid dangerous delays. PATENT LAWYER "Record Send for our that the hydroxide film is McGill Bldg., of Invention" form and Free Book telling How to deposited on both Washington, D. C. Obtain a Patent. Send sketch or model for examination, electrodes. Both electrodes Patents, Preliminary advice without charge. when formed, Trademarks, Copyrights, PatentLitigation Write TQDAY. Highest References. will J. L. JACKSON & CO 419 Ouray Bldg., emit light when alternating current is Handbook for Inventors, "Protecting, Washiggton, 0. C. and Exploiting applied to the electrodes. Selling Inventions,' sect upon request. Science and Invention for March, 1923 _111/11111111111mmoommlputttermewetim)numunmiummuelommIlmtm.I111111111111111111111111111111111111, Let Me Malie The Star A Man. of You Are you dragging yourself about By H. G. WELLS From day to day, always ailing and complaining - always tired and despondent - suffering from (Continued from page 1059) Backache, Indigestion, Constipa t i o n, Dyspepsia, Nervousness. Vital Depletion, etc., etc.-your Biliousness showing in your fare -your lack of energy in your eyes? Have you and your family heavy, rushing without warning out of the given up hope that you will ever into the radiance of be a real man again, achieve suc- black mystery of the sky cess and amount to anything in the sun. By the second day it was clearly the world? Have you lost ambi- a speck tion and allowed your youthful visible to any decent instrument, as ideals to slip down into the bog defects and unfitness? with a barely sensible diameter, in the con- of physical want little while Then, you are the man I Whoops Boys stellation Leo near Regulus. In a to help. an opera glass could attain it. Pull Yourself It Beats 'Em All On the third day of the new year the two hemispheres were Together When you hop into your Auto Wheel newspaper readers of with real steel disc wheels- made aware for the first time of the real Brace up-you can come back Coaster the -there is a way out-you. can be roller bearings and spin down of this unusual apparition in the You -can - ahead of the gang importance a real man again. re- street, you go right heavens. "A Planetary Collision," one Lon- gain your vigor and vitality, your -race or no race! health and strength-you can con- don paper headed the news, and proclaimed the weaknesses that are An Auto Wheel is the speediest quer brain Goes so easy it s opinion that this strange new undermining your body and coaster you ever saw. Duchiné -you can root out the results of almost runs itself --that's due to the planet would probably collide with Nep- Bad Habits and neglect and fill r and joy patented self-contained tune. The leader writers enlarged upon the your life with the success -and they arethrn thoroughlyo nat of of abundant health. factory. topic. So that in most of the capitals It Is Not Too Late. There la on Jan. 3, there was an expecta- hope for you. It doesn't matter the world, what brought you to your present tion, however vague, of some imminent phe- physical condition-it methods s you in the sky; and as the night fol- matterhow1 nomenon have t r i e d in v a i n --or how Auto:Wheel lowed the sunset round the globe thousands often you have been disappointed. wheels eyes to see- You can be saved from the scrap Is sturdily built-steel disc of men turned their skyward STRONGFORT heap of worn-out humanity and with rubber or steel tires; specially con- f amilar stars just as they had al- The Perfect Man be re-builded into a red-blooded steering the old can be re- structed hound brace that makes been. specimen of vital. magnetic Manhood. You easy and safe; auto type hub caps-just ways stored and re-created with like on Dad's machine. It has a brake- Until it was dawn in London and Pollux 'N Everything! Also comes with spoke setting, and the stars overhead grown pale. STRONGFORTISM wheels-all wheels interchangeable. The The Modern Science of Health Promotion to withstand years The winters dawn it was, a sickly filtering Auto Wheel is built Strengfortism will go directly to the root of your of hard play and work. accumulation of daylight, and the light of the cause. Strongfortism will purify trouble and remove strengthen is Auto Wheel's Junior Com- candles shone yellow in the win- and enrich your blood, revitalize your nerves, Below gas and Heart, Lungs, Stomach, Liver, Kidneys, Bowels and panion-The Auto Cart-for your little where people were astir. But your will send the rich, red built just dows to show other vital organs. Strongfortiem nutri- brother or sister. Substantially saw the thing, the blood to every corner of your being, bringing the like the Auto Wheel Coaster. the yawning policeman the agape, Strongfortism write for a catalog. It shows all the mod- busy crowds in the market stopped elltlifeand and buildforceupn muscle and bones the mechanical con- will drive out the poisonous waste matter that has been els and sizes and explains workmen going to their work betimes, milk- in your body and brain and make struction. If you send the names of three accumulating for years in. in your town, telling the drivers of news carts, dissipation and d coaster wagon dealers men, spectivle your sex,age, which one sells the Auto Wheel Coasters, we wander- ternally. I guarantee it-irre going home jaded and pale, homeless occupation or surroundings. give you a year's subscription beats, and in the coun- free to the Auto Wheel Spokes -man, ers, sentinels on their Full Faith 1,a dandy magazine for fellows like trudging afield, poachers slink- Come to Me in try, laborers u. ing home, all over the dusky quickening As You Would to a Brothor chambers of your heart and tell uto e Wheel Coaster Co,, Inc. country it would be seen-and out at sea by Open up the secret me all of your troubles without reservation. You can Tonawanda seamen watching for the day-a great white confide in me with full faith-I will never betray you. North you would to your come suddenly into the westward sky ! Come to me with your problems as New York star, father, mother, brother, or closest friend, and let me Brighter it was than any star in our skies; show you the way out of your difficulties with Strongfort ism-The Beacon Light of Health, Happiness and Suc- brighter than the evening star at its bright- cess. .1 est. It still glowed out white and large, My Free Book no mere twinkling spot of light but a small Send for the "Promotion and Conservation of Health, Strength and round clear shining disk, an hour after Mental Energy" ie the most interesting and instructive Meo or women day had come. And where science has not book you can ever read. It will tell you in understand- We Want 1000 Men can sell our line telling one able, non -technical language, just how you can banish and make big reached, men stared and feared, ca weaknesses your- money if they will another of the wars and pestilences that are self' over into onquersplendid urspecimen of magnetics rbt like these work four to eight Manhood, with 100 per cent. pep and power. It is fiery signs in the the subjects on the free con- , an us ness houses. Boy foreshadowed by these absolutely free. Just mark : ca on uses hens a , y with (write additional ailments on extra line) Conant Quit a $6,000 a year job to take territory heavens. Sturdy Boers, dusky Hottentots, sultation coupon and biz first week. L. O. Keeton on which you want special confidential information us. Geo. Powell made $125 Gold Coast negroes, Frenchmen, Spaniards, send to me with a 10e piece (one dime) to help -pay $252made commissions ceswithn the sun- postage, packing, etc. It's a man -builder --a success absolutely necessary. We train you Free. Prini Portuguese, stood in the glow of maker and a life-saver. Send for my free book Right reach of prospects-cash or easy payments. Write all references. rise watching the setting of this strange Now-TODAY. today 'giving past experiences if any, and The yrFyter Co.. 3347 Fyr-Fyter Bldg., Dayton. O new star. had LIONEL STRONGFORT And in a hundred observatories there Physical and Health Specialist been suppressed excitement, rising almost to Founded 1895 ATENTS, TRADEMARKS shouting pitch, as the two remote bodies had Dept. 201 Newark, N. I. PROTECT YOUR INVENTION! rushed together, and a hurrying to and f ro Prompt, Efficient, Personal Service. to gather photographic apparatus and spec- FREE CONSULTATION COUPON book - N. J.-Please R easonable fee. Full explanation in my troscope, and this appliance and that, to re- Mr. Lionel Strongfort, Dept 201, Newark, Send for free copy today. =end me your book, "Promotion and Conservation of 1 t PATENTS. cord this novel astonishing sight, the des- Health. Strength and Mental Energy," for postage on a ,vhich I enclose a 10 -cent piece (one dime). I have T. BUCKLEY truction of a world. For it was a world, in which am interested. AMBROSE than marked (X) before the subject 150 NASSAU ST. NEW YORK CITY sister planet of our earth, far greater ...Colds ...Blackheads .I..Weak Eyes our earth indeed, that had so suddenly ...Catarrh ...Insomnia ... Gastritis i .. Asthma ... Short Wind ... Heart flashed into flaming death. Neptune it was, ..Hay Fever ... Flat Feet Weakness and squarely, .Obesity ...Stomach ... Poor Circu- which had been struck, fairly ..Headachea Disorders Iation Your Writing Speed by the planet from outer space and the ..Thinness ..Constipation ...Skin Dis - Triple ..Rupture ..Biliousness orders by using JOT, the quickwrittng system. heat of the concussion had incontinently ..Lumbago ...Torpid Liver ... Despond. into one vast mass ...Neuritis ...Indigestion enev LEARN IN FIVE LESSONS turned two solid globes Round world that .. Neuralgia ... Nervousness ... how to copy verbatim speeches, lectures, tele- of incandescence. Round the .Flat Chest ... Poor Memory Shoulders phone messages and verbal instructions. Bet day, two hours before the dawn, went the ...Deformity ... Rheumatism ... Lung Send for details. (Describe) ... Manhood Troubles ter and easier than shorthand. pallid great white star, fading only as it .. Successful Restored ...Stoop MILTON WEND RUBY, N. Y. Marriage ...Youthful Shoulders sank westward and the sun mounted above ...Female Errors Muscular man marveled at it, but of Disorders ...Vital Losses Development it. Everywhere ...Increased ...Impotency ... Great Inalaat all those who saw it none could have mar- Height ...Falling Hair Strength those sailors, habitual .. Diabetes ...Prostate ... Neuras- veled more than ..Pimplea Troubles thenia tl watchers of the stars, who far away at sea and saw it Name Harmless had heard nothing of its advent Removes Stains Full Year's now rise like a pigmy moon and climb ze- Supply with Age Occupation Quickly spa Tweezers 50e. nithward and hang overhead and sink west- Leavesyji(i,_ `ì Trial Bottle 25c ward with the passing of the night. Street Ic Satisfied or And when next it rose over Europe every- City 8tate ...... and \ Money Refunded watchers on hilly beautiful Sc. Dental Mfg. Co., Evanston, Ill., where were crowds of 1118 Science and Invention for March, 1923 BUILDING TRADES slopes, on house roofs, in open spaces, staring eastward, waiting for the rising of NEED MEN! the new star. It rose with a white glow in front, like the glare of a white fire, and those who had seen it come into exis- tence the night before cried out at the sight of it. "It is larger," they cried. "It is brighter!" And, indeed, the moon a quarter full and sinking in the west was in Patent Pend. its apparent size beyond comparison, but scarcely in all its breadth had it as much New brightness now as the little circle of the Invention strange new star. "It is brighter !" cried the people cluster- Makes Happy Feet ing in the streets. But in the dim observa- tories the watchers held If your feet hurt you, you don't feel their breath and good. Don't peered at one another. "It is nearer," they be bothered with sore said. "Nearer!" feet, corns, bunions, blistering hot, or cold feet when you can wear our new And voice after voice repeated. "It is invention. nearer," and the clicking telegraph took that Made Thousands of good jobs up, and it trembled along telephone wires, of soft, pliable, resilient, at good salaries and in a thousand cities grimy compositors sponge rubber and wool felt to be fingered the type. "It is nearer." worn in your regular shoes. THE business tide has turned! Men And the build- writing in offices, struck with a Your feet will assume their ing trades are leading the way back to strange reali- proper prosperity! Government experts estimate zation, flung down their pens, men talking position and stay there, actually mak- that two to four billion dollars will be spent in a thousand places suddenly ing more room in your shoes for building construction came upon a when this this year. grotesque possibility in those words, "It is nature -like pad is inserted. To-day the most vital need of this great build- nearer." ing program It hurried along awakening streets, Our natural air -cushion support is is men-trained men-men who can it was step right in and do the skilled work that build- shouted down the frost -stilled ways comfort personified, and it will do you ing construction requires. of quiet villages, men who had read these a world of good. There things, from is a simple, easy, fascinating way by the throbbing tape stood in Thousands are being which you can prepare for a good position, at yellow -lit doorways benefited every a good salary. shouting the flews to the day and are remodeling You can do it right at home, in passers-by. "It is nearer." their feet spare time, no matter where you live, through Pretty women, without pain into normal feet. the International Correspondence Schools. flushed and glittering, heard the news told Send no money. Give us All we ask is the chance to prove it. That's jestingly between the dances, and feigned an your name fair, isn't it? Then mark and mail the coupon intelligent interest they did not feel. and size shoe. We will mail you a printed below and get pair. the full story of what the ! On arrival pay the postman "Nearer Indeed. How curious ! How clever only I. C. S. can do for you. people $2.00 and postage. Try TEAR OUT HERE - must be to find out things like that !" them for ten INTERNATIONAL - - - - - days. If you are not CORRESPONDENCE SCHOOLS Lonely tramps faring through the wintry delighted we will Box 6190-C. Scranton. Penna. night murmured return your money immediately. A Without cost or obligation, please tell me how I can those words to comfort qualify for the position or the subject postal card will do. marked before which I have themselves-looking skyward. "It has need an X in the list below: to be nearer, for the night's TECHNICAL AND INDUSTRIAL DEPARTM ENT as cold as char- KOMFORT.ARCH SUPPORT Architect Surveying and Mapping ity. Don't seem much warmth from it if Architectural Draftsman Gas Engine Operating it is Blue Print Reading Automobile Work nearer, all the same." COMPANY Building Foreman Airplane Engines "What is a new 327-F West Madison Concrete Builder ]'lumber and Steam Fitter star to me?" cried the Street Contractor and Builder Plumbing Inspector weeping woman kneeling beside her Chicago Illinois Stuctural Draftsman Foreman Plumber dead. DStructural Engineer Heating and Ventilation The schoolboy, rising early for his ex- Electrician Sheet Metal Worker amination work, puzzled Electrical Engineer Steam Engineer it out for himself- Electrical Contractor DRailroad Positions with the great white star shining broad and Electric Wiring El Chemistry bright through Mechanical Engineer Pharmacy the frost -flowers of his win- A DAY Mechanical Draftsman Metallurgy dow. "Centrifugal, Machine Shop Practice centripetal," he said, S'ellrn e Shirts Mining Engineer with his $25Large Toolmaker Navigation chin on his fist. "Stop a planet in shirt manufacturer wants agents OCivil Engineering Mathematics Radio its flight, rob it of its to sell complete line of shirts, pajamas, BUSINESS TRAINING DEPARTMENT centrifugal force, and nightshirts direct to wearer. Ad- what vertisedto Business Management Salesmanship then? Centripetal has it, and down a patterns-easy Industrial Management Advertising it falls into se. No experience re-y Personnel the sun! And this-!" quired, Entirely new proposition. Organization Better Letters "Do we come in Write for free samples. Traffic Management Foreign Trade the way ? I wonder-" Medium Shirt Co., SOS Business Law Show Card Lettering way, N.Y.C. io Banking and Banking Law Stenography and Typing The light of that day went the way of its Accountancy Teacher brethren, and with the later (including C.P.A.) Civil Service watches of the Nicholson Cost Railway Mail Clerk frosty darkness rose the strange star again. Single Acting High Speed Accounting Common School Subjects And it was now Model Steam Bookkeeping High School Subjects so bright that the wax- Engine Business English Illustrating ing moon seemed but a pale yellow ghost of Type Q. Stationary-1 in. bore Private Secretary Cartooning itself, x 1 1/8 in. stroke. Weight. 8 Business Spanish French rising huge in the sunset hour. In a lbs. 6 ore. Price complete, South African city a great man $17.00, forwarded prepaid. Name had mar- Many other types model En- ried, and the streets were alight Beditionoilers,of ccitalogueS20c Street to welcome larged en- Address his return with his bride. "Even the skies (refunded oneefirst odrder) have illuminated," said Bathe Mfg. Co., Dept.2-5214WoodlandAve.,Phila., City the flatterer. Under Pa. State Capricorn, two negro lovers, 'daring the wild Occupation beasts and evil spirits, for love of one an- Persona reeiding in Canada should send this coupon to the other, crouched together Internoh onnl Correspondence 6ohools Canadian, in a cane brake SYCO-GRAF Limited, Montreal, where the fireflies Canada. hovered. "That is our 1 S. Patent Allowed star," they whispered, and felt strangely A Micro -Physic Machine comforted by the sweet brilliancy of its Amazingly increases the strength of light. the feeblest psychic impressions. A mechanical oulia. Operates for one person. Prepaid $5.00. Free JARN The master mathematician sat in his pri- Booklet. vate room and pushed the papers The Sycn-Graf Company from him. Dept.A,P.C.Box HóºEEY His calculations were already finished. In 934. Richmond. Va. a small white phial there still remained a YOU can make $15 to $60 weekly in your spare little of the drug time writing show cards. No canvassing or that had kept him awake toyou Free 80 days trial soliciting. We instruct you by our new simple and active for four long nights. Each 'for on approval. Your Directograph choice of 44 Styles, colore and sizes of system, pay you cash each week day, serene, explicit, patient as ever, he the famous Ranger Bicycles. Express pre- and guarantee you steady work. Write for full had given paid. i Factory-to-Rider Prices. particulars andfree booklet. his lecture to his students, and ovv imfdtitdeM WEST-ANGUS SHOW CARD SERVICE then had come back at once to this moment- IAntlISIOmIwemail me this payments. 67 Colborne wheslmpadeumez n et Building Toronto. Can. ous calculation. His face was grave, ires a lit- able factory prices and marveloae clisse. tle drawn, and hectic from his drugged Cycle £ompany óAáÿ fer activity. For some time he seemed lost in Mead thought. Then he went to the window, and the blind went up with a click. Half way up /You can be quickly cured, if you the sky, over the clustering roofs, chimneys, and steeples of the city, hung the star. STAMMER Wonderful, new device, guides your hand; corrects He looked at it as one might look into the Bend 10 cents for 288 -page book on Stammering and your writing in few days. Big improvement in three Stuttering, "Its Cause and Cure." It tells how I hours. No failures. Complete outline FREE. eye of a brave enemy. "You may kill me," cured myself after stammering 20 yrs. B. N. Bogue, Write C. J. Ozment. Dept. 44 St. Louie. Mo. he said after a silence. "But I can hold Bldg.. 1147 N. 116 8t.. Indianapolis. 1119 Science and Invention for March, 1923 you-and all the universe for that matter- in the grip of this little brain. I would not change even now." aWeek He looked at the little phial. "There will $100 be no need of sleep again," he said. The next day at noon, punctual to the minute, he entered his lecture theater, put his hat on the forWork end of the table as his habit was, and care- , fully selected a large piece of chalk. It was ree his students that he could not is '., a joke among Railroad Fare that lecture without that piece of chalk to f um- ble in his fingers, and once he had been pia 4 , stricken to impotence by their hiding his y He came and looked under his BECOME a high- - supply. salaried cartoon- gray eyebrows at the rising tiers of young ist: --One of the fresh faces, and spoke with his accustomed asiest, pleasantest and of phrasing. "Circcm- nest paid of all busi- studied commonness nesses. Millions of dol- stances have arisen-circumstances beyond tars spent last year on my control," he said and paused, "which will serious, comic, sport and animated cartoons-and the course I had the demand for cartoons increases every day! debar me from completing to at Home designed. It would seem, gentlemen, if I Easy Learn clearly and briefly, that- A new method, prepared by one of America's may put the thing 'oremost cartoonists, makes learning cartooning actual man has lived in vain." fun. You learn at home, yet all your work receives at one another. Had !hrough the mail the personal, individual attention The students glanced if prominent cartooning experts. Training starts at they heard aright? Mad? Raised eyebrows very foundation of cartooning-covers every branch lips there were, but one or two Many and grinning -teaches you to draw cartoons that SELL. intent upon his calm gray - ,Eudents earn big money from cartoons even before faces remained inishing course. fringed face. "It will be interesting," he Send for Free Book was saying, "to devote this morning to an Our new Free Book, "How to Become a Cartoon- exposition, so far as I can make it clear to ist," is crammed full of interesting details about the calculations that have led me to Student Winding a Stator :artooning-opportunities, stories of leading cartoon- you, of ists, letters from students, and full details about this this conclusion. Let us assume-" some -study method. No obligation. Mail post card He turned toward the blackboard, meditat- To the Great Shops of sr letter for book TODAY. ing a diagram in the way that was usual WASHINGTON SCHOOL of CARTOONING `lived in 1133 Marden Bldg. Washington, D. C. to him. "What was that about vain'?" whispered one student to another. "Listen," said the other, nodding toward the lecturer. env oyne And presently they began to understand. We pay your railroad fare to Chicago-the That night the star rose later, for its Electrical Center of the World-from any place proper eastward motion had carried it some in the United States. Grasp the opportunity toward Virgo, and its to see the country at our expense. Come to ç way across Leo Get a y Coyne-learn electricity in 3l'i months. brightness was so great that the sky became complete training so you can make big money blue as it rose, and every star as Power Plant Operator, Superintendent, a luminous Telephone man, Construction worker, auto, and planet was hidden, save only Jupiter near truck or tractor electrician, battery man, radio the zenith, Capalla, Aldeebaran, Sirius, and expert, or you can go into business for your. of the Bear. It was white and self as electrical contractor, dealer, auto igni- Your Choice the pointers tion or battery expert and make from $3,000 to beautiful. In many parts of the world that $20,000 a year. Hundreds of our graduates 52000 MUSICAL night a pallid halo encircled it about. It was today are making big money and you can do the INSTRUMENTS perceptibly larger; in the clear refractive same if_ yougrasp this opportunity-act now. sky of the tropics it seemed as if it were nearly a quarter of the size of the moon. The frost was still on the ground in Eng- Learn Electricity land, but the world was as brightly lit as if FREE could 3%2 it weie midsummer moonlight. One In Months We have a wonderful new system of teaching note music by mail and to the first pupils in each locality we will give see to read quite ordinary print by that cold No books or useless theory. You are trained on free a $20.00 superb Violin, Tenor Banjo, Ukulele Hawai- $100,000 worth of electrical equipment. Everything ian Guitar. Banjo, Guitar Banjo-Ukulele Mandolin clear light, and in the cities the lamps from door bells to power plants. You work'on motors. Banjo -Mandolin or Cornet absolutely free. A very small generators, house -wiring, autos, batteries, radio, charge for lessons our only expense. Pay nothing if you burnt yellow and wan. switch -boards, power plants-everything to make - step into a position do not learn to play. We also teach Piano and Organ the world was awake that you an expert ready 'to right Complete outfit free. Write at once, no obligation. And everywhere paying from 845 to $100 a week. SLINGERLAND SCHOOL OF MUSIC night, and throughought Christendom a som- 1815 Orchard St., Dept. 176 Chicago, I1L ber murmur hung in the keen air over the of bees in Radio Course FREE countryside like the buzzing the We include the following free with the regular course; THE MIDGET "F IVE -IN -ONE" SLIDE RULE the heather, and this murmurous tumult (1) A complete course in auto, truck and tractor elec- le a combination Mannheim. Log -Log and outlay of ny,F+ Add snd Subtract, Polyphase,' and grew to a clangor in the cities. It was the tricity storage batteries. Greatest 4..e' Binary Slide Rule. It will instantly add, auto, electrical and battery equipment in the country. uubtrae m ltiply and divide any com- tolling of the bells in a million belfry towers (2) in marvel of the age. Con- *: invol .... ole numbers, Course Radio-the h w,w', á t le d mix d o moere. and steeples, summoning the people to sleep structing, installing and operating. You can build possible and power a `` a every root you own wireless telephone set. The graduations in t ' r tc f very quantity. no more, to sin no more, but to gather Alt metal, a teed with (3) A life scholarship in the Coyne school. You can ad i * printed ana _ Hite oannlná a ere grease their churches and pray. And overhead, tt-y as long as you wish and return for further teal f. Whileitisthemeetverea- training at any time In the future. til caleala tor ever invented, Ifs opera - growing larger and brighter, as the earth s n e simple4 e and easily understood. .41e Diameter 4 incbes. rolled on its way and the night passed, rose i Price with 16 page Instruction Book, Earn While You Learn "a,_. F' t1.60, Leatherette carrying clue 60c the dazzling star. Catalogue money We help students to secure jobs to earn a good part -rte' backaIf ouere not eeatiefied. And the streets and houses were alight of their expense while studying. SLIDE RULE CO. Niles, Mich. GILSON in all the cities, the shipyards glared, and CONVERT YOUR BICYCLE INTO whatever roads led to high country were Send Coupon Now lit and crowded all night long. And in all Don't delay a minute-send that coupon in right now A MOTOR -CYCLE the seas about the civilized lands ships with for our big free catalog and full particulars of Free Railroad Fare offer. Act now ! with a Steffey Motor Attach. throbbing engines, and ships with bellying ment. Fits any ordinary bicycle. creatures. B. W. COOKE, President \ ` i" Easily attached. In use for over sails, crowded with men and living - Trade and Engineering School t - f 21 years. PRACTICAL, ECO were standing out to ocean and the north. Coyne , i'''' NOMICAL, RELIABLE. Dept. 5333. 1300-1310 W. Harrison St., CHICAGO i,-4 ' For already the warning of the master Send stamp for circulars mathematician had been telegraphed over STEFFEY MFG. CO., Dep. E. 5025 Brown Street, Philadelphia, Pa. B.W. Cooke, Pres, Coyne Trade and Engineering School. the world, and translated into a hundred Dept. 5333, 1300-1310 W. Harrison St., Chicago, III. estling Book FREE tongues The new planet and Nleptune, lock- Dear Sir: Please send me free your big catalog and Tale bow to be great athlete d of your special offer of Free Railroad jy.G,.% tae wrestler bow to wIN. Startling aeereta ed in a fiery embrace, were whirling head- full particulars in wer )ea by orid c. ge Fare and two extra courses. peepleas Farmer Burns and Frank Gotch, Be long, ever faster and faster, toward the strong healthy thletic. Bmdle big men with seas. fo self deteoee. He a lender. Mee and sun Already every second this blazing mass ,1.1 boys, write for Frae Book today. State year age. Name- arms BiwniSd ito1,1253 Bailwey Bldg..Omaha, Nel flew a hundred miles, and every second its terrific velocity increased. As it flew its course, it must pass a hundred million of Address - TELEGRAPHYMorse and Wireless) and RAILWAY ACCOUNTING taught thoroughly. Endorsed by Big salaries : great oppovtunities. Oldest, largest school. miles wide of the earth and scarcely affect it. Telegraph, Railway, Radio, and Government officials. ExPenees opportunities to earn large portion. Catalog free. its destined path, as yet only DODGE'S INSTITUTE, A Street, Valparaiso, Ind. But near 1120 Science and Invention for March, 1923 slightly perturbed, spun the mighty planet Jupiter and his moons sweeping splendid "Recommended around the sun. Every moment now the at- Why Miss Half the s."aent traction between the fiery star and the great- ,f fo est of the planets grew stronger And the r result of that attraction? Inevitably Jupiter, Fun inZfe: would be deflected from its orbit into an Everyone admires and wants elliptical path, and the burning star, swung to dance with the person who knows the latest steps. There by his attraction wide of its sunward rush, is no need of being a wall- would "describe a curved path" and flower! Arthur Murray, Amer- perhaps ica's foremost dancing teacher. collide with and certainly pass close to, our has perfected a wonderful new earth. "Earthquakes, volcanic method by which you can learn' writes a happy outbreaks, any of the newest steps in United Y. M. C. cyclones, sea waves, floods, and a steady rise a few minutes and all of the A. Schools' stu- in temperature to I know not what limit"- dances in a short time. d e n t, formerly Even if you don't know one of Scranton, Pa., so prophesied the master mathematician. step f r o m another, you can and now in the And overhead, to carry out his words, quickly and easily master any employ of the dance without music and with- lonely and cold and livid, blazed the star of out partner, right in your own United States home. Your success is guayan government. the coming doom. teed. The Vanderbllts and scores if other socially prominent people To many who stared at it that night until have chosen Mr. Murray as their their eyes ached, it seemed that it was visi- instructor. More than 90,000 people have learned to become popular daueers through his easy learn -at-home bly approaching. And that night, too, the methods.dancing weather changed, and the frost that had gripped all Central Europe and France New Easy Way He was an office clerk, working long hours. He and England softened towards a thaw. To show you how easily and quickly you can learn his that he was tied down new way, Arthur Murray has consented to send, for but a says "the light had dawned" But you must not imagine because I have limited time, to routine work for all time unless he trained him- a special course of sixteen dancing lessons hours spoken of people praying through the night for only $1.00. This extraordinary offer is made to prove self. So he decided to devote spare evening you will enjoy learning the newest steps in the privacy of to our excellent correspondence course in account- and people going aboard ships and people your own home-without onlookers to embarrass you. ancy. He earned a salary increase of 60 per cent. fleeing towards mountainous country that You need not send any money now. When the postman and in a year quali- hands you the 16 lesson course, just deposit $1 with before completing his course, plus him, fied for United States Internal Revenue service the whole world was already in a terror be- a few cents postage, In full payment. If within five days you are not delighted, return the lessons and your (Pittsburgh Division) as auditor of income taxes, cause of the star. As a matter of fact, use money will be promptly refunded. with a further substantial increase of salary and and wont still ruled the world, and save for This unusual responsibility. offer may not be made again. Write the talk of idle moments and the splendor today for the sixteen lesson course. If you prefer, send The course he selected is just one of more than of the dollar now and we will pay the postage. The lessons three hundred that we offer, all reasonably priced, the night, nine human beings out of will be sent promptly, in plain cover. Learn at home a tell and surprise your friends, Act now and be a good dancer all bringing the close personal service that is were still busy at their common .ocupa- 50011. feature of United Y. M. C. A. Schools instruction tions. In all the cities the shops, save one ARTHUR MURRAY, by mail. here and there, opened and closed at their Studio 642, 801 Madison Ave., N. T. C. Do you want more power, more money, a proper hours, the doctor and the under- broader field? Write us about your ambi- taker plied their trades, and workers gath- BE A free. Soon REAL MAN tion and get our friendly counsel ered in the factories, soldiers drilled, LOOK LIKE ONE AND you, too, can be throwing up your hat over scholars studied, lovers sought one another, FEEL LIKE ONE the advance you have macle. thieves lurked and fled, politicians planned Broaden your shoulders, deepen their schemes The presses of the news- Your chest, enlarge your arm, and get a development that will 300 papers roared through the nights, and many attract attention. Fill yourself Some of our Correspondence Courses full of Business Courses a priest of this church and that would not energy and be powerful. Accountancy Bu.iness Law open his holy building to further he My New Book Advertising Complete Letter -Writing what "Muscular Development" Baskin` Office Management considered a panic. Better Letter. Public Speaking foolish Will Explain How Booktininess Ip Arithmetic Secretarial The newspapers insisted on the lesson of This book is illustrated with 26 Administration(ration full page Business Stenos aphyYriting the year 1000-for then, too, people had an- photographs of myself Business Finance Traffic Management and of some of the world's fin- Courses ticipated the end. The star was no star- est developed athletes I have Technical and Other trained. It will interest Agricultural Courses Insurance Courses mere gas-a comet; and were it a star it and Applied Psychology Mathematical Courses benefit you greatly. Architecture Mechanical Engineering could not possibly strike the earth. There Automobile Courses Own -Your -Home Course Send IOc (stamps or coin) Building Conatruction Plan Reading was no precedent for such a thing. Com- for a copy NOW, today Civil Engineering Courses Plumbing while it is on your mind. Drafting Cooreee Poultry Husbandry mon sense was sturdy everywhere, scorn- Electrical Courses Radio Engineering EARLE LIEDERMAN, Dept. 203, 305 Broadway English Courses Radio Telegraphy ful, jesting, a little inclined to persecute Factory Management Steam Engineering Courses NEW YORK CITY Foreign Languages Structural Drafting the obdurate fearful. That night at 7:15 Foremanship Surveying nyship Use of the Slide Rule by Greenwich time the star would be at its High SchoEol Courses Vocational Coidan« nearest WALTER GEMS Illustrating to Jupiter. Then the world would Look Like Diamonds see the turn things would take. The master See how they sparkle and flash! mathematician's grim warnings were treated We defy you to tell the difference. Correspondence Chaire of gold or white platinum - fin- by many as so much mere elaborate self - ish setting. Instruction advertisement Common sense at last, a lit- SEND NO MONEY Wear one (or both) five days tle heated free. Write us what you want 347 Madison Avenue by argument, signified its unalter- -ladies' or men's ring er stick pin and setting wanted. able convictions by Send strip of paper for ring size. On arrival, deposit going to bed. So, too, with postman $5 for each $2 Dept. e4 -m ring, for each pin. Deposit NewYorkCity barbarism and savagery, already tired of refunded within 5 days if not entirely pleased. Without obligating me, please advise regarding the course in the novelty, went about their nightly busi- R. WALTER, 299-13 Montgomery St., Jersey City, N. J. ness, and save for a howling dog here and there the beast-world left the star un- Name heeded. CHARGE And yet, YOUR OWN BATTERY Full Address when at last the watchers in the You can dolt -without removing your (Please write plainly) European states saw the star rise, an hour battery or even disconnecting terminale. The Valley Beni Charpr will end your battery later, it is true, but no larger than it had troubles. Plugs in on lamp socket; clampa been the night before, there to battery. Cannot overcharge or harm men with training are In de- were still plenty g tai ^~ battery. Price $18.00- Send for booklet. mand. For more than a quar- awake to laugh at the master mathematician Valley Electric Company Electrical ter of a century this school has Department been training men of ambition and limited time for the -to take the danger as if it had passed. eguis S. ST, LOUIS, MO. electrical industries. Condensed course in Electrical enables grad- But hereafter the laughter ceased. The uates to se- Engineering cure good star grew-it grew with a terrible steadiness You can be quickly cured, if you positions and promotions. Theoretical and Practical Elec- hour tricity. Mathematics. Steam and Gas Engines andMechan- after hour, a little larger each hour, a teal Drawing. Students construct dynamos, install wiling little nearer the midnight zenith, and bright- and test electrical machinery. Course with diploma er STAMMER complete and brighter, until it had turned night in- Send 10 cents for 288 -page book on Stammering and to day. Had it Stuttering, Its Cause and Cure." It tells how I In One Year come straight to the earth cured myself after stammering 20 yrs. Over 3001) men trained. Thoroughly B. N. Bogue. equipped fireproof dormitories, dining instead of in_ a curved path, had it lost no 792 Bogue Bldg.. 1147 N. Ili. St., Indianapolis. hall, laboratories, shops. velocity to Jupiter, it must have leapt Free catalog. 30th year opened Sept. 27,1922 the Genuine Foreign Stamps-Mexico War Is- BLISS ELECTRICAL SCHOOL intervening gulf in a day; but as it was 158 sues, Venezuela, Salvador and In- 406 TAKOMA AVE., WASHINGTON, D. C. it took five days altogether to come by our dia Service, Guatemala, China, etc. Only 10C Finest Approval Sheets 50 to 60 per cent. planet. The next night it had become a AGENTS WANTED. Big 72-p. Lists Free. third the size of the moon before it We Buy Stamps. Established 29 years. 5 Master Keys set Hussman Stamp Co., Dept. 133, St. Louis, Mo. Work like magic in emergencies or prove to English eyes, and the thaw was assured. whether your door or padlocks are burglar- ex---" BECOME A proof. Open and test thousands of different It rose over America near the size of the e''W- LIGHTNING locks. Recommended by users in ten dif- TRICK CARTOONIST" ferent nations. Most wonderful and only moon, but blinding white to look at, and today. Novel Make money chalk talking. Send $1.00 foe snappy keys of their kind. Send $1 hot ; and a breath of hot wind blew now program of Inch drawinge. with instructions, by pro. key chain FREE with set. fessional rtoonist. Satisfaction guaranteed. Circular MASTER KEY CO., 8-0 Manhattan Block, Milwaukee, Wig, with its rising and gathering strength, and fro. Balde Art Seek., Dept. 4, Oshkosh, Wis. Science and Invention for March, 1923 1121

in Virginia and Brazil and down the St - Crystal Receiving Set Lawrence valley it shone intermittently N396 No. through a driving reek of thunder clouds, $ 4 27 $2.50 flickering violet lightning, and hail unprece- dented. In Manitoba were a thaw and dev- This is the Rit- floods. And upon all the moun- ter Grand Crys- astating y tal Set. It has tains of the earth the snow and ice began a variable tun- to melt that night, and all the rivers coming ing capacity of flowed thick and turbid, 150 to 600 out of high country meters and our and soon-in their upper reaches-with Of guarantee to swirling trees and the bodies of beasts and receive concerts men. They rose steadily, steadily in the n 25 miles under 4a' normal condi- ghostly brilliance, and came trickling over ten Ú N2 5 tions. their banks at last, behind the flying popu- >eV Free circular of lation of their valleys. set with Instruc- c tions on How to And along the coast of Argentina and up Your N°2 Direct -K1 ël N Aerial sent upon the South Atlantic tides were higher than $224 $ 348 ettuest. they had ever been in the memory of man, "SPECIAL and the storms drove the waters in many GET THIS WONDERFUL RING. If You Can Tell It From a Genuine Diamond Send It Back OFFER" cases scores of miles inland, drowning whole These amazing, match mon iievrWdb,,les i flash addzzzgn1 Ritter Grand cities. And so great grew the heat during play of livingdiadneyaa rainbow fire. They, alone, stand the diamond testa. Includingterrific aeldtestofdlrectcomparison.Lifetimeexperta Crystal Set with the sun was like toaee any difference. Prove this yourself. equip- the night that the rising of need allteir experience full aerial of a shadow. The earthquakes Wear a Corodite Diamond 7 Days Free ment and single the coming Make thin test. You risk nothing. Wears genuine Corodito and guaranteed phone all down America a diamond side by side on the same finger for 7 days. If you with head band. began and grew until or your friends can tell the difference, send It back; you won't be Ail boxed. Cape Horn hill- t s Ingle penny. That's fair enough. If you keep the ring the neatly from the Arctic Circle to price printed here Is all you pay. No installments. Remember. sides were sliding, fissures were opening, Corodite, alone have the same cutting as genuine stnnea. Price, $5.00 No. 1-Ladies' Solitai-e 141r Gold S. Ring . 52.84 timid d. Ring . . . 53.48 and houses and walls crumbling to des- No. 2-Gents' Heavy Belcher 141k 27 ALSO INVITE DEALERS' Ne. 3-Gente' MBaesfve Hex oa Gypsy Ring WE truction. No. 4-Ladies' Hand-Carvedaaeket Betting, plat, finish 3.88 IN(li'IRIES No. B-Ladies' Tiffany Bridal Blossom Engraved . . 3.84 Caratsize gems. Beautiful mountings of most modern design, China was lit glowing white, but over Charge of gold or latest whits platinum finish. Unqualified 20. RADIO CORPORATION year guarantee. Handsome art -leather case free with each ring. RITTER Japan and Java and all the islands of east- yoar money right at home. Just NO MONEY $Ee Daeaandtng New York City ern Asia the great star was a ball of dull SEND Bend nae, hen 118 Walker Street wanted and size shown by will of toWhen around finger joint. Your ring will comevlw return mall. red fire because of the steam and smoke and above with postmen. you d arrlvea deksett amount eroda sad spouting forth to Yours one to keep rIm after 7 dart' ned.' Send hack ashes the volcanoes were Your money will be Immediately returned.' Send ttoday. salute its coming. Above were the lava, hot E. RICHWINE CO. S. Dearborn St. Dept. 383 , Chicago, Illinois gases, and ash, and below the seething floods, Sole Importers Genuine Corodite Diamonds introducing the New Sun Automatic Reg- and the whole earth swayed and rumbled ulator and Timer for Ford Cars. Give(' pro- with the earthquake shocks. Soon the im- per spark automatically for every speed of memorial snows of Tibet and the Himalayas MADE TO YOUR t motor. Does away with Spark Lever. Back-kick were melting and pouring down by ten mil- Impossible-Insures in- lion deepening converging channels upon stant start in all weather. Prevents fouling of spark the plains of Burma and Hindustan. The plugs and forming of car- tangled summits of the Indian jungles were bon. Engine remains clean giving more power on hills, aflame in a thousand places, and below the I1ltS1 more speed on level roads hurrying waters around the stems were dark NO EXTRA at less cost. Grease, dirt and waterproof-Fully objects that struggled feebly and reflected CHARGES guaranteed. Sold on 30 days the blood red tongues of fire. And in a rud- Send no We make this special trial. Retail price $3.50. offer for 30 dare to Large income for active workers. Tremendous derless confusion a multitude of men and Money prove the wonderful sales opportunities. Every Ford owner will buy. women fled down the broad riverways to value, style and fit of Progress Tail- AUTO SUN PRODUCTS COMPANY. oring. We will tailor to your special that one last hope of men-the open sea. order, a pair of these stylish, $6.00 pants Dept. 31 Cincinnati, Ohio -guaranteed to wear like iron-and semi Larger grew the star, and larger, hotter, them to you postage prepaid for only $1.95. Send no money or measure- and brighter with a terrible swiftness now. ments until you receive our samples. The tropical ocean had lost its phosphor- I Write for Samples Today. Electric Solder Iron escence, and the whirling steam rose in you the s Fits Standard Appliance Plug emeday yourtreques received. Any ghostly wreaths from the black waves that sac plunged incessantly, speckled with storm AGENTS WANTED-germloS3selt- tfa every weak. taking orders from tossed ships. your friends and neighbors for our high- tailoring. No Suite a $12.4p and yentaenntience at $1.95 up make 100 IG'atts 108-115 Volts And then came a wonder. It seemed to orders c easy Fall details will be Beet RADIO-AUTO-HOME those who in Europe watched for the ris- free. Write now. Does Work of Any $15.00 Iron. The Pro g Tailoring Co., Dept.Q429, Chicago, III. lise your own appliance plug, or ing of the star that the world must have send $1.00 extra for Plugs and ceased its rotation. In a thousand open .50 Cord as shown. Plain String Sol - der, 60e lb. Acid or Rosin Core spaces of down and upland the people who Printing ChemCheap e. Iron only Solder 90c lb. Add IOe for . _. Cards,circulars,labe String had fled thither from the floods and the Larger $35 Job press $150. Save money. Print postage. for others, big profit. All easy, rules sent. M. A. SIMON CO., 520 Pine Street, St. Louis, Mo. falling houses and sliding slopes of hill Write factory for prese catalog, 1YPE,carde, ZIP -ZIP etc. THE PRESS CO., D-47, Meriden, Coen. BOYS: If you like hunting and outdoor sport, you cannot afford to CHARGE YOUR RADIO BATTERY AT HOME do without this remarkable shooter. with an Scientifically and practically made, prong made of beautiful metal, fine Zip -Zip rubhers with plenty of pep and force. Thousands of boys are made A -C CHARGER happy with this wonderful Zip -Zip. Orderel us or SELF POLARIZING-Connects either way to bat. your dealer. tery. Zip -Zip complete 35c. 3 for $1.00 iimillehimmi GIVES AUTOMATIC TAPER CHARGE-Prevents AUTOMATIC RUBBER CO. injury to battery through overcharge. Dept. 33 Columbia, S. C. STANDARD FUSE protects against fire hazard. 5 AMPERE CHARGING RATE-The correct for all radio and auto batteries. C BringsBi(In5Sections s) 3 ft. Telescope is miles away The A C Charger constructed of high-grade people and objecte materials; closed cors, transformer; genuine black an5ju,tlitetheyreas you never did be- fore,3See Brass bound, useful and enter - glazed porcelain panel. Handsome black enameled gaining. "Could tell color of finish. r plane 4 mues away"-Mrs orbrough. "watch my number ºeas - freight ears mil e The A C Charger always gives satisfaction. Its boy - ar ese muontaineon moon" ile.veatchool -A. C. Palmer. Thousands pleased. rugged construction and scientific design insures -Mrs. Hornaway SPECIAL OFFER - send only 25e with ,rder. On arrival deposit $1.75 with postman, its uninterrupted service. lr If you prefer Bend $1.85 with order in full payment. Sent Postpaid. Batiaf 1 buy hundreds of kinds w calmness Some worth 31 to 31 each. S,mple outdoor work wrth my ,gammon, factor...pose jut. Co.postedGet r Seed M coati (NOT STAMPS) for my Illustrated HOLMES ELECTRICAL MANUFACTURING CO. R.,. MR. SINCLAIPARK.R, DEALER IN INSECTS, OFPf. 33. OCEAN CALiF. 3229 Sheffield Avenue CHICAGO, ILL, 1122 Science and Invention for March, 1923 watched for that rising in vain. Hour fol- with that dull stupidity that hunger, fatigue, Dr.T.O'Conor lowed hour through a terrible suspense, and heat, and despair pir9loane the engender, there were still WIli TeachYou star rose not. Once again men set their men who could perceive the meaning of eyes upon the old constellations they had these signs. Star and earth had been at counted lost to them forever. In England their nearest, had swung about one another, it was hot and clear overhead, though the and the star had passed. Already it was re- C ground quivered ; perpetually but in the ceding, swifter and swifter, in tropics the last stage Bet InYour Sirius and Capella and Aldebaran of its headlong journey downward into the showed through a veil of steam. And when sun. at last the great star rose, near ten hours And then the clouds WnHome late, gathered, blotting out the sun rose close upon it, and in the the vision of the sky; the thunder and light- Good chemists command high center of its salaries. Industrial firms of all white heart was a disk of ning wove a garment around the world; all kinds pay tempting salaries to go. black. the right men. Salaries of $10,000 over the earth was such a downpour of a year are not unusual for chem- When over Asia the star had rain as men had never ists of exceptional abilities. The begun to seen before; and work 'of the chemist is extremely fall behind the movement of the sky, and where the volcanoes flared red against the interesting. If you are fond of then suddenly, as it hung cloud canopy there descended DR T. O'COa'OR experimenting, take up chemistry. over India, its torrents of SEGANE A. B. If you want to earn more money. light had been veiled. All the plain of India mud. Everywhere the waters were pouring the way is open through our from the mouth CECdaratiwtal Dir for Course in Chemistry. of the Indus to the mouths off the land, leaving mud stilted ruins, and Nero York formerly of the Ganges was a shallow waste the earth littered like a Tremens. merfeax You Can Learn at Home of shin- storm worn beach Ch iced Society and Dr. Sloane will teach you Chem- ing water that night, out of which rose tem- with all that had floated, and the dead bodies a, ede iced emote,ct istry at home eheetiet as o,e, in a practical, in- ples and palaces, mounds and of the men and brutes, a noted instructor, G tensely interesting way. Our hills, black its children. Course is remarkably simple. No with people. Every minaret was a cluster- For days the water streamed off the land, Special education required-if you can read and write plain English you can thoroughly ing mass of people, who fell one by one into sweeping away soil and trees and houses in undoratand and master every lesson. the turbid waters as heat and terror over- the way and piling huge dikes and scooping Easy Monthly Payments came them. The whole land seemed a-wail- out titanic gullies over the countryside. 'fits price of ear course la very low and the tuition Includes every- inr. and suddenly there swept Those were thing, even the chemiatry outfit-there are no extrae to buy with a shadow the days of darkness that fol- our course. You can pay in small monthlymounts as you go along. across that furnace lowed Our plan places a chemical education within the reach of despair, and a breath the star and the heat. All through of everyone,, of cold wind, and a gathering them, Experimental Equipment of clouds out and for many weeks and months, the Given to Every Student of the cooling air. Men looking earthquakes One epeeist feature of our course fa that we give to every student, up, near continued. without additional charge, the chemical equipment he will need for blinded, at the star, saw that black his etediee including forty-two pieces of laboratory *operatingand disk was But the star had passed, and men, hunger - eighteen different chemicals and reagents. The fitted, heavy creeping across the light. It wooden box serves as a carrying ease for the equipment was the moon, driven and gathering courage laboratory accessory for performing and se e coming only slowly, experiments, between the star and the earth. And might creep back to their ruined even as men cried cities, bur- SPECIAL 30 -DAY OFFER to God at this respite, ied granaries, and sodden fields. Such few additione aree out of the east with a strange, Yo to r0 fid at about it, Mail the Coupon to-day inexplicable ships as had escaped the storms of that fnafor freebook, Oprtunitie, for Chemist,,"and full de tail. of our swiftness sprang the sun. special offer. Act . .. ediately before this offer in And then star, time came stunned withdrawn. sun, and and shattered and sound- CUT moon rushed together across the ing HERE -- heavens. their way cautiously through the new Chem ical Institute of New York, Inc. marks and shoals of once (Home familiar ports. Ext. Division 3A). 140-D, Liberty St., N. Y. City So it was that presently, to the European And as the storms subsided men perceived Without obligation or cost, send me your free book, watchers, star and sun rose close upon each that everywhere the days were hotter than "Opportunity for Chemists," and full particulars about other, drove the Experimental Equipment given to every student, your headlong for a space, and then of yore, and the sun larger, and the moon, plan of payment and special 30 -day offer. slower, and at last came to rest, star and shrunk to a third of its former sun merged size, took Name into one glare of flame at the now fourscore days between its new and zenith of the sky. The moon no longer new. Address eclipsed the star, but was lost to sight in the brilliance But of the new brotherhood that grew of the sky. And though those who presently among City State were still alive regarded men, of the saving of laws it for the most part and books and machines, of the strange To Practical Men and Electrical Students: Yorke Burgess, founder and head of the famous Electrical Mathematics, Electrical Units, Electrical electrical school bearing his name, has prepared Connections, a pocket-size Calculating Unknown Resistances, note book especially for the practical Calculation of man and those who Current in Branches of Parallel are taking up the study of Circuits, How to Figure Weight electricity. It contains drawings and of Wire, Wire diagrams of Gauge Rules, Ohm's Law, Watt's Law, electrical machinery and connections, over Informa- two tion regarding Wire used for Electrical Pur- hundred formulas for calculations, and problems poses, Wire worked out showing Calculations, Wiring Calculations, how the formulas are used. Illumination Calculations, Shunt This data is taken from his personal Instruments and note book, How to Calculate Resistance of Shunts, Power which was made while on different kinds of work, Calculations, and it will Efficiency Calculations, Measuring be found of value to anyone engaged Unknown Resistances, in the electrical business. Dynamo and Dynamo Troubles, Motors and Motor Troubles, and Calcu- The drawings of connections for electrical appa- lating Size of Pulleys. ratus include Motor Starters and Starting Boxes, Also Alternating Current Calculations in finding Overload and Underload Release Boxes, Revers- Impedance, ible Types, Reactance, Inductance, Frequency, Elevator Controllers, Tank Controllers, Alternations, Speed Starters for Printing of Alternators and Motors, Press Motors, Automatic Number of Poles in Alternators Controllers, Variable Field Type, or Motors, Con- Controllers for ductance, Susceptance, Admittance, Angle Mine Locomotives, Street Car Controllers, Connec- of Lag and Power Factor, and formulas for use with Line tions for reversing Switches, Motor and Dynamo Transformers. Rules and Rules for Speed Regulation. Also, The book, called the "Burgess Connections for Induction Motors Blue Book," is and Starters, published and sold by us for one dollar ($1.00) Delta and Star Connections and Connections for per copy, postpaid. Auto Transformers, and Transformers If you wish one of the books, for Lighting send us your order with a dollar and Power Purposes. The drawings also bill, check or show all money order. We know the value of the book kinds of lighting circuits, including special controls and can guarantee where Three and its satisfaction to you by return- Four Way Switches are used. ing your money if The work on you decide not to keep it after Calculations consists of Simple having had it for five days. THE McCLURE PUBLISHING CO. 720 Cass St., CHICAGO, ILLINOIS Science and Invention for March,. 1923 1123 change that had come over Iceland and Greenland the shores of Baffin's Bay, so that Finish Tom Mix the sailors coming there presently found The Proper them green and gracious, and could scarce believe their eyes, this story does not tell. Uses Nor of the movement of mankind, now that Makes NewFurniture the earth was hotter, northward and south- ward towards the poles of the earth. It Reituide concerns itself only with the coming and Harmonize the passing of the star. "I own a complete set of Renulife Violet Ray and find it of immense value in retaining a robust physique. I The Martian astronomers-for there are With the Old find it especially helpful in curing the sprains and astronomers on Mars, although they are bruises that I often incur in my strenuous career.'' different beings from men-were naturally profoundly interested by these things. They saw them from their own standpoint, of Do You, Too, Want Health course. "Considering the mass and tempera- ture of the missile that was flung through and Strength? our solar system into the sun," one wrote, YOU can have vigor, energy, health, strength and beauty. You need not suffer from aches and pains "it is astonishing what little damage the -from rheumatism, neuritis or other ailments. earth, which it missed so narrowly, has sus- The soothing, healing Renulife drives out aches.and tained. All the familiar continental mark- pains without shock or unpleasant sensation and searches deep down in your body to eliminate the ings and the masses of the seas remain cause. It carries ozone into the blood, enriching intact, and indeed the only difference seems and purifying it. to be a shrinkage of the white discoloration Hundreds of people have been (supposed to be frozen water) round either Free Trial rejuvenated and strengthened by the health -giving Renulife Violet Ray. pole." Which only shows how small the Prove to yourself how quickly it will aid you. Our vastest of human catastrophies may seem free trial plan enables you to use Renulife for that at a distance of a few million miles. ailment of yours. Write for this Free Trial Plan-

R R R w un. 1 u we take the risk. nuunnunngi Itllltllllltttli i illttitili iti m i i nnnununnunu i. m m.n nndnn.nnmmuuuw Renulife Electric Company Now *Rd is the 319 Newberry Bldg. Detroit, Michigan WarChd SMALL odd pieces of modern furni- Pitt St. F., Windsor, Ont.) ture add greatly to the attractiveness (In Canada: By HARRY VAN DEMARK of every home. You, yourself, can easily (Continued front page 1057) make them for your family. There is no particular trick to constructing porch meters high, or about 36 feet, as the river swings, tables, telephone sets, etc. You Electricity Erie, the three can give your work a beautiful finish then only drained Lake for Taught by Practical Men other lakes had their own separate outlets with If you expect to become an electrical expertn three or fourthe you e to the sea. The water falling over it was - uni g wrongw 'Bin an electrical engineer ,e a real - b and n< wwb learned ove Haphazardp i ru may get you for a t .. but lI only about 15 per cent of what falls today. not give you nthe solid undation tfor tthe big iet bry. the wearing l'eu get the cry training without losing .'day from your present The channel cut was narrow, ark.e Learn at hetne in your pare time. Hundred. of Burge.. trained men back of it followed very slowly, only about JOHNSON'S hav th.. and . g bigger sal. rt Burgeu Home Study Methods are approved 12 centimeters or 5 inches, in a year. SRGEs by Electrical Engi . If you are m mane. to eed 'n any branch of Elecericfty, write u. today.o Let us .how you how h men .o After various geologic changes, all five hey keep on going. Wino for the tBurge.. ca log on "Electricity." tells of opponumti even lakes sent their water over Niagara, which and how Burgeu Methods train you for them. is divided into two falls, the smaller YORKE BORGES, Consultors Enº.nevi today OOD DYE American, and the Horseshoe Falls, fall- BURGESS ELECTRICAL SCHOOL the Dye is very easy to 745 E. 42nd St., Dept. 2 Chicago, Ill. ing from a height of about 50 meters (164 Johnson's Wood Canadian Branch. 201 Crawford Street. Toronto. Ont.. Canada. feet) into the cavity, giving an awe-inspiring apply-it goes on easily and quickly, display of the primitive powers of nature. without a lap or a streak. It penetrates ELECTRICAL HANDBOOK In later times, a wearing away of the edge deeply bringing out the beauty of the We have prepared a pocket Mze note book lair practical rnen. Con- of the falls of a little over five feet, has grain without raising it-dries in 4 hours tains drawings and diagrams of electrical machines and connections; over 200 formulas. with problems worked out been calculated. A number of geologists, and does not rub off or smudge. Made in "THE BURGESS BLUE BOOK" . draw.nos for Motor Sorter. Con - roller.. Tran.lormer., Rever..ne Swahe.. Lighting Cirruns. C.Icutauone to Spencer, Taylor, and Gilbert, have on the fourteen beautiful shades. elude Electrical Mathematic. Ur... Re.'on e. Wife G.., e Rule.. Ohm'. Law. Unknown R....oce.u Dynamo TeoublesAtoo Alternating Current Calcula - basis of all the circumstances during the none. Ending Impedance. Frequency. 5p_ed.. Power Factor. Formula. Ive Line Tr.n.former.. my post aida money back a r,ntee course of geologic epochs, tried to reckon aPVTSGEÌ Sl O n the time which was required for Niagara E -This Book on Consulting ElectricalEngineers FRE THE BURGESS COMPANY, 745 East 42nd St. Radio Apparatus and Supplies Chicago, Ill. to cut the entire channel or gorge. They reached figures varying between 20,000 and 40,000 years, giving a mean of 30,000 years Home Beautifying per year). Agents: 90c an Hour (or at a rate of about one foot Book tells how to finish wood Introduce e'Sodereze." A new wonder. A At this rate Niagara Falls would reach This pure solder in paste form. Works likenAgic. and enameled Stops all leaks. For mending water buckets, Buffalo in about 90,000 years, but less water in artistic stained cooking utensils, milk pails, water tanks, tin now passes over the falls, due to hydro- effects. Gives practical suggestions on roofs-everything including granite ware. agate ware, tin, iron, copper. zinc. etc. electric power developments, and also a making your home artistic, cheery and harder rock has been reached by the falls, inviting. Tells just what materials to use Quick Sales-Nice Profit which wears away but slowly. and how to apply them. Includes color 'a Everybody buys. Housewive, me- covering capacities, etc. Use chanics, electricians, jewelere,plumb- card-gives ere, tourists, automobiliste, etc. No coupon below. a leak too bad to repair. Just apply a PHOTO -BY -WIRE FOR THREE little "Soderete, ' light a match and that's all. Put up in handy metal tubes. Carry quantity right FRENCH CITIES with you. Write for money -making proposition. AMERICAN PRODUCTS CO.. 7841 AneriCall Bldg.. Mich". Obi° Edouard Belin, inventor of the photo-tele- phonic process by which photographs are ALL MAKES transmitted through the air and by wire, has t'nderwoods, Monarchs, Reming- gone to Lyons, where he will establish the t.ons, L. C. Smiths, Olivers, first of three stations, under the contract Royals, Coronas AT controls REDUCED PRICES. II with the French Government, which Prices as low as.... communications and which sees a future in No. 15 Write for our Catalog M. Belin's new . system. The New York TYPEWRITER CO. World recently acquired from M. Belin the BERAN Chicago Dept. 21, 58 W. Washington Street, North American rights of the invention. S. C. JOHNSON & SON, Dept. SI 3. Il There will also be installations of the Racine, Wis. (Canadian Factory-Brantford) Belin equipment at Paris and Strassburg. l'lease send me free and postpaid your Instruction Book on Home Beautifying and Wood Finishing. Renewed efforts to put the ' apparatus in between Madrid and Paris were f rus- The best dealer In paints here is action 1 Eels Mink,Mnskrats and other in the early tests by poor service. An fur -bearing, animals, in large trated 1 Catch Fish numbers, with our new, Fold- hour was spent in efforts to talk over the MY NAME 1 Trap. It catches them 1 ing. Galvanized Steel Wire and line; but nothing more than dim "hellos" re- MY ADDRESS like a fly-trap catches flies. Made in all sizes. Strong 1 durable.. Write for Descriptive Price List, and our Free sulted, so it was decided that it would be use- 1 for attracting all kinds of fish. CITY & STATE Booklet on best bait known . a J. F. GREGORY, Dept. 25, Lebanon, Mo. less to try to transmit photographs. 1124 Science and Invention for March, 1923

_ _ Doctor Hackensawps Secrets By CLEMENT FEZANDIE (Continued from page 1065) ;Il,,,ul111111J111J,,me1181:11otelog,,,,,,,,,ollructu,,m,,,,,,,,,llmuull.1111111111111u11111ele1111,

"Well, yes, it is a glider, and yet in my opinion it is far superior to the ordinary glider. You have probably seen in the pa- tENK pers that both the French and the German governments are devoting considerable atten- AUTOM TIC i tion to the manufacture of airplanes without engines. The results have been most prom- Here's The Winner of ising, some of the flights lasting three hours and a quarter without a motor of any kind. V0TORCH The $5000 Cup Shorter flights have also been made with a Gentlemen-meet Mr. Otto Loesche, winner of passenger on board as well as the pilot." the $5000 Penrose Trophy in the annual Pike's "But how can an airplane travel without a Peak Automobile Race in 1920 and first in his A Marvel of Utility class in 1921. motor?" For lank Automatic $1.50 Mr. Loesche is not only a champion automobile wind raises it, the fixing the wiring on your "The same wind which car, mending kitchen utensils, repairing electric racer, but he's chief of the experimental depart- raises an ordinary kite. The difference is fixtures, working around your Radio set. ment of the Lexington Motor Company. That's Absolutely a pretty good job for a young man. that the glider needs no string to hold it in automatic-blows itself-produces the position the wind. a 1400° needle -point flame instantly. Recently, when asked for a statement concern- proper against The Used by electricians, mechanics and ing the one thing that had contributed most to pilot, on board the machine, by means of experimenters his success, he said: his steering apparatus, keeps the wings fac- 60" coil self -fluxing (acid or rosin core) "I believe the greatest source of assist- ing the wind, and so is able to rise to any solder $ .25 ance and encouragement came to me when Lenk "Super" (Mouth Blow Torch) .75 I became interested in trying to better my desired height-that is, of course, so long as Lenk "Jumbo" (Mouth Blow Torch) 1.00 position. I wanted an education-that is, conditions remain favorable. Marvel Soldering Kit-one Lenk Auto- a foundation on which to build. So I en- matic and one coil, each of self -fluxing rolled as a student in the Mechanical En- "The disadvantage of these gliders, as acid and rosin core solder, in neat gineering Department of the International at present constructed, is that the equilibrium leatherette case 2.00 Correspondence Schools, of Scranton, Pa., is not automatically regulated. It requires an If your dealer does not carry them, order direct. and began to study. There is no question in my mind but that was the most impor- expert pilot to run them, and the steering Lenk Manufacturing Company tant step of my life." is very fatiguing. Then, too, the starting is 42 Portland St. Boston, Mass. Why don't you at least find out what the I. C. S. difficult. It is not every hill that can serve as can do for you? It doesn't cost you a penny or a starting -point, and the wind must be just obligate you in any way to mark and mail the coupon printed below, but that seemingly simple right. To obviate this difficulty, the French The Patient Teacher little act may be "the most important step" in are trying hard to devise a glider in which ART STUDENTS: Would you like to your life, too. the pilot can assist himself by a kind of have a teacher standing by your elbow Today-not "Tomorrow"-is the day to make bicycle treadle which enables him to a while you work ready to make a the first definite toward work stroke or move Success, propeller. This would be of material as- two for you whenever you are in doubt, to INTERNATIONAL CORRESPONDENCE SCHOOLS sistance in starting." show you how the picture goes? The Box Scranton, 8189-C, Penna. "And your machine ?" Patient Teacher will furnish as much help as Without cost or obligation on my part, please tell me how I can qualify for the position or in the subject before you ask for .and no more. It will furnish which I have marked an X: "My machine is really a combination of an airplane and a balloon. But why waste outlines of any size desired of any photo- BUSINESS TRAINING DEPARTMENT graph or drawing. It will guide your every ['Business Management ['Salesmanship time describing it. Come along with me and D Industrial Management Advertising you can see it for yourself. The man from stroke if you are a beginner; or it will help O Personnel Organization Better Letters you over Traffic Management ['Foreign Trade Missouri who wants to be 'shown', is the the difficult parts while leaving you Business Law ['Stenography and Typing man who free to express your own individuality. Banking and Banking Law Business English will learn." Accountancy (including C.P.A.) Civil Service A short ride in one of the doctor's auto- The Patient Teacher is used, not only for en- Nicholson Cost Accounting Rallway Mail Clerk larging pictures, but when you are posing a friend ['Bookkeeping Common School Subjects mobiles brought the pair to the hangar where or sketching a landscape. Write ['Private Secretary D High School Subjects for full particu- ['Business Spanish French Illustrating the motorless airplane was stored. lars of the instrument and instructions for a "You course of practice that will develop ability to do TECHNICAL AND INDUSTRIAL DEPARTMENT see, Silas," observed Doctor Hack- original work. Inexpensive. Mention this maga- Electrical Engineering Architect ensaw, "one great advantage of my ma- zine. Electric Lighting Blue Print Reading Mechanical Engineer Contractor and Builder chine is that I do not require a large space to PATIENT TEACHER COMPANY' 232 West Mechanical Draftsman Architectural Draftsman start in, because I rise vertically instead of 116th St., P. O. Box 32, New York City Machine Shop Practice ['Concrete Builder ['Railroad Positions C Structural Engineer horizontally. Here is the machine-now ['Gas Engine Operating [C Chemistry ID Pharmacy tell me frankly what you think of it." ['Civil Engineer Automobile Work RADIO SUPPLIES Surveying and Mapping ['Airplane Engines The reporter cast a disappointed look at Metallurgy Agriculture and Poultry the All Standard Goods-Immediate Deliveries Steam Engineering Radie ['Mathematics airplane. Save that it had no propeller Distributors and no motor, it was very much like any for Name BALDWIN, BRANDES and FEDERAL PHONES, 6-20-22 other flying machine except for the one fact FADA, FEDERAL and MONROE Street Address that, instead of being a monoplane or a RECEIVING SETS City State bi -plane, this machine had no less than four Erla, Acme, Dubilier, Chelten, Burgess, Meyers Tubes, Magnavox 1 8. 2 Rev planes. This gave it a rather clumsy ap- and many others. Occupation pearance. A Complete Line. Largest Stock in the Middle West Persons residing in Canada should send this coupon to the WRITE FOR International Correspondence Schools Canadian, Limited, LATEST 64 -PAGE CATALOGUE Montreal, Canada. "I see you don't like the looks of my DEALERS 35% DISCOUNT `quadriplane,' " remarked the doctor, notic- American Radio Mfg. Co., Dept. F. ing the reporter's air disapproval. ` ff of "Well, 107 E. 13th STREET KANSAS CITY, MO. "ELECTRO - CONDITE I don't blame you. I haven't sought beauty STARTLES THE WORLD yet, I'm just seeking practical results." You positively can install and repair Thousands of people are marveling at any electrical job wonderful "But this machine is only a glider !" cried in the home or the performance of the "Elec- business place without previous ex- tro -Condite" Converter. Clarifies, puri- Silas. "It has no motor, nothing to make perience. You can eliminate elec- fies, sterilizes, matures and mellows it go!" trician's bills when you own our most kinds of beverages. Makes hard new book, ELECTRICAL KINKS, water soft, etc. May poisoning. "It looks so, doesn't it?" chuckled the explaining everything about bells, prevent lighting, wiring, vacuum Send for device 5 garage $5.00 with days' doctor. But she'll go all right !" Then turn- cleaners, washing machines, etc. trial money-back guarantee or ask for Easy money made working for others. circular. ing to the man in charge, he added: "Run her to SEND TODAY, $1.00 each, or Best grade Proof Hydrometers, $1.00 out the starting -place, James,-that C. O. D., plus postage. Satisfac- each prepaid. is, if she's in good order." tion guaranteed. Circular free. "Electro- Dept. X., 200 West 72d St., New York "She do be that, sorr," returned the man. HOME BOOK CO.. 388 CD Arcade Bldg.. Cleveland, 0. CONVERTER A -B -C LABORATORIES, Inc. "She hasn't lost a foot of gas since last night." "Gas?" exclaimed Silas Rocket, "where is LEARN WATCH REPAIRING there any gas?" You can learn by our modern and orig- inal system of instruction every pari TAM m E R MORE "Why, Silas; didn't I tell you that my ma- of the Watch Repairing Trade at home Kill the fear of stammering. Re-education the as good than a shop. YOU try. The widely chine was a combined glider and balloon,- moneywhileh sad famed Hatfield Method fully wellpa rtee position or start is brine.. afet r outlined In an accurate, dependable. worth- and did you ever hear of a balloon without t:12 rang sun tour!, of inetruetim. Good hile book-"HOW TO STOP STAMMERING." It w` stab repairera are w err sod own has inspired thousands. Free copy today. any gas?" from $30 fn $65 per week. Far particulars apply to the THE HATFIELD INSTITUTE,. 109 N. DearbinhC111020.III But in where the world is the gas?" M IWAUNEE SCHOOL OF WATCH REPAIRING.166 Mason St.. MILWAUKEE,WIS Science and Invention for March, 1923 1125 "In the wings, my boy. You will notice that the wings of my machine are consider- ably larger and thicker than those of the ordinary airplane. The space between the upper and lower portion of each wing is filled with helium gas. In a word, each wing is a little balloon, and the combined TrueTone balloons are sufficient to raise the machine DirectorofGenc into the air:" Rodem ich's Or. chestrailear the Saxophone "I see." premier South- Easiest of all wind instruments "When I first set out to ern Orchestra build this machine in Brunswick to play and one of the most I looked at the problem in this way. If I Records (for beautiful. You can learn the Dancing),play- scale in anhour'epracticeand play could only find some simple means of rais- popular music in a few weeks. 1 n g Buescher ing a glider to a height, I could do away Band Instru- Youcan take your place in aband within 90 days if you so desire. with a motor altogether, for I could vol- ments. Unrivalled for home entertain- ment, church, lodge or school. plane or dive down in any direction I pleased e c In big demand for orchestra and at a high rate of speed. 0 dance music. In fact, by utilizing the wind, I could do all that the Free Trial order any glider does now, and far more, for my o tier Buescher instrument without acquired velocity in descending en- i would tis> 3_ paying in advance and try it able me to make six days in your own home, with- better use of the wind out obligation. If perfectly eatie- power. .I could Electrical Engineer fied, pay for it on easy payments to tack, somewhat as a sailing suit your convenience. 76 per cent of all vessel tacks, and so profit to the utmost by popular phonograph records are played with Buescher In- struments. Ask for pictures of the Nation's Record Maker's whatever breezes there happened to be. meter money year. Hence I could travel a long distance before In One Year Saxophonea Book Free eaed In. struments are almost entirely displaced Ly SaaophoneeSaxophones 1n having to rise again." all nationally popular orchestras. Our Free Saxophone Book at this Famous School tellº which Saxophone takes violin, cello and bass parta and Silas Rockett's face showed plainly his onanyother things you would liketoknow. Ask for your copy. Mention the instrument interested In and a complete catalog poor opinion of the machine. It doesn't No calling offers such unbounded opportunities will be mailed free, strike me as being practical," said he, at to the modern ambitious young man as that of BUESCHER BAND INSTRUMENT CO. length. "Your invention is nothing but a Commercial Electrical Engineering. It is for this Makers of Everything In Band and Orchestra Instruments reason that this gi'eat school has organized a spe- 6073 Buescher Block ELKHART. INDIANA balloon, with wings added for coasting down. cial course in Commercial Electrical Engineering But each time you go up, you have to fill it that may be completed in one year. Sax Invented the Saxophone with fresh gas, and each time you come Within recent years the Electrical field has be- come so wide and diversified that there has Buescher Perfected It down you have to let the gas escape. The sprung up a great demand for Electrically trained advantage over an ordinary balloon seems to business men, consulting and efficiency engineers, me very slight." men who can handle Commercial and Engineering problems. This special course offers a thorough, "You're right, Silas," said Doctor Hack- condensed, and very practical Electrical Engineer- ensaw approvingly, "or at least you would ing training, especially adapted to high-school be right if I were foolish enough to waste graduates. Here, you will also find any other kind of Elec- my gas at each descent. But I do no such trical education which you might desire. School a thing " of Engineering is the largest institution in Amer- I TEACH BY MAIL "How do you manage, then ?" ica devoted exclusively to the teaching of Elec- I can make a good penman tricity and allied subjects. of you at your home during "In the first place I use helium gas, so as spare time, no matter where you live or ELECTRICAL ENGINEERING bow poorly you write. My simplified to avoid all danger of fire. Then, if you will system has shown thousands the way to With B.S. Degree in 3 Years good penmanship the notice, I have a specially constructed heat- fie years-it CANandKLL do the ing apparatus here. I use kerosene for fuel. A faculty of specialists is leading hundreds of ambitious same for YOU. young men to a sure and substantial success. Why not My beautifully il- When I heat the helium gas, it expands, and you? lustrated 32 -page consequently the wings of my machine bulge If you lack some of the educational requirements, you Book, can make them up as you go along. This gives you the NI> out and occupy more space, the machine thus opportunity of becoming an electrical engineer in the .. l've :"'improve-made ,u moub "How to Become awder 9w..w.. Good shortest possible time. ''Xm,9O C 9WOPr., a Penman," becoming lighter. Finally it becomes light / FREE! enough to rise from the ground, and I can ELECTROTECENICS e.e4 It contains many Only one or two years of this course, and you are a beautiful spec 1 - control its rate of ascent by means of the mens of penmanship showing what others fully trained electrotechniclan-prepared to fill such po- have accomplished by the Tamblyn Sys- temperature." sitions as general plant superintendent, director of con- tem, with testimonials and general infor- struction, superintendent of maintenance, chief draftsman, mation about our courses. (Your name "I see." etc. This course will equip you for a position between elegantly written on a card if you enclose that of an electrical engineer and that of an electrician, stamp for postage.) Ladies taught as suc- "When I have reached a sufficient height which Is a well paying position, leading to higher execu- cessfully as men. Write Today. Address and wish to coast down, I turn off the heat. tire work. A grade school diploma or its equivalent ad- F. W. TAMBLYN, mits you without examination. New terms open every 424 Ridge Bldg., Kansas City, Me., U.S.A. The cold air of the heights, acting on the three months, enormous wing surface, cools the gas al- PRACTICAL ELECTRICITY most instantly, especially as the cooling is This complete six months' electrical course teaches you assisted by rotary fans, worked by the mo- house, factory and theatre wiring, testing and meter work,. J.C. and D.C. motor installation, repairing and mainten- tion of the airplane, and which I can start ance, Including shop work in A.C. and D.C. armature or stop at will. The helium gas contracts, is! iding and all necessary mathematics. A three months' course in A.C. and D.C. armature my machine becomes heavier than air, like an winding, or in light and motor wiring. ordinary glider, and down I coast in any AUTOMOTIVE ELECTRICITY direction and at any speed I please, turning Electrical specialists who instinctively diagnose and on the heat when I wish to rise again." locate automotive electrical troubles command high posi- BLUE PRINT READING tions and are well paid. Specialize in starting, lighting, GOOD MEN WANTED NO MATTER WHAT "You have an answer for everything, doc- ignition and storage batteries, and command a big Job at TRADE. learn to read Blue Prints and get a a big salary! rig job as Foreman and Superintendent. You will earn tor," remarked Silas. "You must have given There are millions of automobiles, motor trucks, trac- pore money. We will teach you quickly In your the subject a great deal of study." tors, rxotorcycles, aircraft, farm lighting plants, but few -;,are time. Don't miss this chance. Write today-state real experts who can put their fingers right on electrical ,r trade. We will send you blue print. Catalog B. "I should say so. I began my experiments troubles. nr,d valuable facts, all free. Speciallete teach this course on actual standard equip- BE A DRAFTSMAN-Earn $35-$100 a week. We forty years ago. I first experimented by ment-three months day school, or through home study. train you quickly at home on the pay as you study Dlan. fastening men to kites of various kinds and Come any time and we will put you In the thick of the Book and tools FREE. Write for Catalog O. work. Dept. 18-A, Drexel Bldg, Philadelphia, Pa. sending them up in the air. I tried the or- Fill out the coupon and mail it today. COLUMBIA CORRESPONDENCE SCHOOL í9O4 dinary kite with a tail, the tailless kite, and the box -kite. But the weight of the kite - CCCHOILof ENGINEERING string that had to be lifted was the great of Milwaukee drawback. I used for the purpose a very Founded ELECTRICITY light yet strong clothesline, but my kites 1905 TWO-YEAR COURSE IN EIGHT MONTHS could not lift very much of it. Then, too, the Thousands of trained men needed in the electrical industry. School of Engineering of Milwaukee, understood, latest training methods wind would change and my kites with their Most effective, easiest S.1.-3, 415 Marshall Street, Milwaukee, In existence. Proper home training service now within the human freight, would drop to the ground. WIs. electrical engi- Without obligating me In any way, please reach of every ambitious man. Practical Illustrated mail frse neering complete. a book value. My passengers were always provided with book and further particulars on the course I Free, 56 -page of great have marked with an X. INSTITUTE parachutes, but when one man broke a leg Dept. 1, WORLD TECHNICAL ....Commercial Electrical Practical Electricity Jersey City, N. J. in falling, I gave up the attempt. Then the Engineering ... -6 Mo. complete COuras airplane was invented, and now the gliding - .... Electrical Engineering, B.S. Degree ....3 mo. Armature Wind- TO THE MOON AND BACK IN machines are doing such remarkable work .... Electrotechnics Ing course NINETY DAYS that I decided to take up the subject ....Drafting .... 3 mo. Light and Mr. again ....Automotive Electricity tor Wiring A thrilling story of blended science and adven- on these new lines. And here is the result. ture. By John Young Brown. A.B. Scientifically you If will take your place in the machine, Name Ass accurate, delightfully and absorbingly interesting, I'll be the pilot, and we can take a trial spin." profusely and beautifully illustrated, good print and binding with title and side stamp in gold. "What !" Street City State $2.50. Postage free. "Yes, I want you to come for a little ride LUNAR PUBLISHING CO., Box 462-E, Providente, Ky. with me around New York Harbor." Educatici 1126 Science and Invention for March, 1923 "But "Surely you're not afraid, Silas? Some Seller at "No, replied the reporter, dubiously, "but are you sure the machine's all right AGENTS "I'll answer for it, sorr, said the mechan- Looks Like $50° Worth 00 in it $ Ram ic, reassuringly. "Me and Bill was out Gives You $1.10 yesterday, and she worked like a charm!" Profit: Too much preoccupied to notice the dis- crepancy in the pronodns, Silas took his seat, though not without some hesitation. He didn't much like the idea of being made the subject of an experiment. "That's right, Silas," cried Doctor Hack- ensaw, encouragingly, "A brave man can only die once!" But poor Silas did not feel disposed, at the moment, to die even once. Doctor Hackensaw stepped into the pilot's seat and turned on the heat. Almost instant- ly the wings of the machine began to swell to several times their original size. and the machine slowly rose and began tugging at the ropes that held it down. $12 YOUR BOY'S HAPPINESS "Now Silas," cried the doctor, "before we AN HOUR! start take a good look at your parachute. In W. H. Marion, a beginner, sold 36 "Nifty is one of your first considerations. Get The Nine" Introductory Assortments in three hours, BOYS' MAGAZINE for him. He needs this great case of any accident, grasp that, and it will first day, $38 profit ! How? Our representatives intro- boys' periodical. Parents owe it to their sons to break your fall. We're all ready, James, duce our products with a first sale of beautiful combin- give them clean, interesting and instructive read-, ation sets of Toilet Articles, Soaps, etc. You sell at half manly and let her go!" store prices,' no fancy talk sell on sight. Make 20 to 80 ing that will make them self-reliant, sales a day with $1.10 profit on each. Easy to average courageous. A moment later the released machine rose 1100 a week. Could you ask more while Introducing slowly from the ground. The wings them- line, establishing a permanent business for yourself 7 AN 8 Another plan calls for no deliveries, no investment, MONTHS' selves were so designed as to tilt upward, no delays. You bank quick profits. Also a winning thus facilitating the rise, but the seats of premium plan. Write quick for full details. TRIAL SUBSCRIPTION coantest. EveryCarabsproducelutelyr the passengers always remained horizontal FORD FREE! geNots For d o FOR ONLY 50 CENTS! free. Most amazing offer ever made. Don't waste a minute. whatever the position of the car. A special Write TODAY for othetrated are explaining oar finite. (This is way below the regular price) telephone in the car enabled the two pas- Piano including 30 other package,. ACT NOW. Each issue of THE BOYS' MAGAZINE con- sengers to converse as easily as if in a quiet E. M. DAVIS CO. Dept. 6703 CHICAGO tains from two to four splendid serial stories and parlor. from twelve to twenty thrilling short stories, be- sides special departments devoted to Radio, Me- Doctor Hackensaw was jubilant. "You see, chanics, Electricity, Popular Science, Athletics, Silas," he observed, "We have none of the It Will Pay YOU to Own Physical Training, Stamp Collecting, Outdoor noise and fuss here of an ordinary airplane. Sports, Amateur Photography, Cartoonit.g, etc. Beautiful big pages with handsome covers in col- We are rising quietly and steadily. That's A MONARCH Junior Lathe ors. Profusely illustrated throughout. A big lot one great advantage over the flying -machine, Hundreds of things, of metal or wood, for the shop, auto of Jokes and Comic Drawings. Eight issues equal the ease of starting. We do not require and home can be made with a MONARCH Amlior 20 big volumes, which would cost, as books, at Lathe. This sturdy, small engine lathe, guaranteed to least $20.00. a special aviation field, I can rise or land work with 1/1000 of an inch accuracy, was especially A special feature is the award of $220.00 in most anywhere, because my ascent is prac- designed for inventors, experimenters and small shop for in many Then, too, the start and owners. It is easy to learn to operate-even beginners cash prizes the best amateur work tically vertical. can't Jam it. subjects. There is no reason why YOUR boy the landing are effected as slowly as I wish, Equipped with should not win some of these prizes. Remember, thus eliminating two of the greatest dangers automatic safe- only 50 cents for eight months. If you are not ty devices. satisfied, we will refund your money promptly and of the airplane, which must start or land at without question. Remit in stamps if more con- a high rate of speed. For war -purposes, 9" lathe venient. too, this faculty of hovering is very useful. 2% -ft. bed (On sale at all newsstands -10c a copy.) with bench For example, we are now directly above the legs 11111111111111111111111111n1111111111,,,,11, 11111111111111111,111,1 1111 1,,,,,1,1111n1111nnenmm, Woolworth building. See how easy it would TEAR OUT HERE be to drop a bomb on it from here-much $225 The SCOTT F. REDFIELD CO., easier than from a balloon, for a balloon is 9242 Main St., Smethport, Pa. SEND for Free catalog of MONARCH lathes which are at the mercy of the wind, while I can re- built up to 30" swing I accept your special half-price introductory offer main in the same relative position by des- and enclose 50 cents for which send THE BOYS' MAGAZINE for eight months cending in a spiral toward the building." The Monarch Machine Tool Co. to 418 OAK STREET SYDNEY, OHIO (Write name and address plainly) Silas looked down and was forced to admit the truth of his companion's remarks. Name "Don't you see," cried the doctor, exult- ingly, "that my machine combines the ad- GENUINE Street or R.F D vantages both of the balloon and of the airplane. I can travel in any direction I GERMAN City State please, like an airplane, and yet haven't the MAUSER Ppri es Latest model 9 shot automatic. Shoots stand- ard cartrid es-lies flat in pocket- World's famous Luger 30 cal. $20.75 - 25 Hand Ejector Revolver, cal. swing out cylinder 32 cal. 32 cal. $13.95 LEARN THE CODE AT HOME $16.95. 38 cal. $17.9$. All brandnewlatestmodels. Guaranteedgenuine imported. PaY ca Delivery "Just Listen --The Omnigraph will do the teaching" with the Plus Postage SEND NO MONEY Satiefaetioa guaranteed or mossy prompap refunded 25 cal. Pocket Automatic; 26 cal. Blue Steel Army Automatic $8.45; 32 cal. $10.45; Officer's Auto- OMNIORAPH , 95 matte, 8 safeties, 25 cal. $11.95; Military Trench Automatic, 82 cal. 10 shot extra magazine FREE, THE OMNIGRAPH Automatic Trans- $11.65. Just like you need over there. Imported mitter will teach you both the Wireless 6 Top Brake Revolver. 92 cal. $8.85; 38 cal. $8.95, and Morse Codes-right in your own Universal Sales Co. 141 B'way, Desk 278 New York home-quickly, easily and inexpen- sively. Connected with Buzzer, Buzzer and Phone or to Sounder, it will send you unlimited messages, at any speed LATHES from 5 to 50 words a minute. 9 to 18 -inch Swing THE OMNIGRAPH is not an experiment. For more than 15 years, it has been sold all over List price S 150 and up, the world with a money back guarantee. The according to size. When OMNIGRAPH is used by several Depts. of the ready to buy, send for II. S. Govt-in fact, the Dept. of Commerce uses the OMNIGRAPH to test all applicants applying for a Radio Lathe Catalog and prices. license. The OMNIGRAPH has been successfully adopted by the leading Universities, Colleges and Radio Schools. W. F. &John BarnesCo. Send for FREE Catalog describing three models, $14 to $30. DO IT TODAY. 442 Ruby Street ROCKFORD, ILLINOIS 22 Hudson St., New York City With Good Pay The Omnigraph Mfg. Co., A Job For Life and Treatment Annual Vacation and Sick Leave under "Uncle Sam," If you own a Radio Phone set and don't know the code - you are missing most of the fun is open to you if between the ages of 17 and 65. Our free book "B-41" will tell you about It.. Write today. CHICAGO CIVIL SERVICE COLLEGE, 807 Kenner Building, ChI$. s Science and Invention for March, 1923 1127 heavy and finicky motor to bother with - nor the expense of the gasoline. Traveling is cheap for me. What does it matter if I do Your Choice not travel quite so fast. I can attain any speed I please in my descent. Neither do I waste my helium gas, as the ordinary bal- loon does, because I do not allow the gas 75c a Week to escape." The machine was now well up in the air, and the doctor decided to make his first downward dive. He accordingly turned off the heat, the rotary fans began to revolve - the wings collapsed to a fraction of their former thickness and the car began to glide downward through the air at a rapidly in- creasing speed. When the motion became too swift, Doctor Hackensaw with a dex- terous swerve of the tail would start the ma- We have cut chine rising again. "Look Silas," cried the doctor, gleefully, the price "Here we are over Coney Isaand ! If you one-half look sharp, you will see, some distance be- yond the bathing place, a basket floating out in the ocean. We'll suppose that's a sperm - whale, and I'll show you how easy it would No matter what your occupation, one of be to harpoon it, with a buoy attached to the the home study sets listed below will quickly harpoon, and then follow the buoy in our fit you for a better job and bigger pay. Any set machine without any of the dangers we you select will be sent for seven days' examination, and if you decide to buy you may pay the rock - should run in a whale -boat." bottom price at the rate of only 75c a week. But "Why, doctor, I didn't know you were you must act now 1 The rising cost of paper and the !" binding materials won't permit us to continue such an expert exclaimed Silas admiringly, present low prices much longer. he his companion as saw the ease with which These books are the work of recognized author- handled the machine. ities. They are written in plain, easily understood Scarcely were the words out of his mouth, language, by recognized authorities, and contain however, when he was startled by a crack- hundreds of photographs, diagrams, tables, etc., that make difficult points as simple as A.B.C. ling sound-the steering wheel broke, and Handsomely and durably bound in half or full Bound the machine, no longer under control, began morocco leather (except as noted), and stamped in a series of headlong dives. gold. "Quick, Silas !" cried the doctor, "Take Volume No. 9 to your parachute, man! Quick, I tell you, or you'll be in the ocean!" Pay -Raising Books May, 1921 -April, 1922 Suiting the action to the word, Doctor At Greatly Reduced Prices CONTAINS Hackensaw chose an opportune moment and jumped clear of the falling machine. His Business Management, 8 vol., 2500 pages, well il- parachute opened beautifully and down he lustrated. Was $52.50 Now $29.80 1200 Pages with over 1500 Carpentry and Contracting, 5 volumes, 2138 pages. came lightly among the gaping crowd of 1000 pictures. Was $37.50 Now 19.80 Illustrations bathers on the Coney Island beach. Civil Engineering, 9 volumes, 3900 pages. 3000 Poor Silas, however, was not so fortunate. pictures. Was $67.50 Now 34.80 and Electrical Engineering, 8 vol., 3800 pages. 2600 It took him some time to understand how pictures. Was $60.00 Now 29.80 stuck Articles by the matters stood, and then his parachute Automobile Engineering, 6 volumes, 2600 pages, Over 700 and refused to come free from the falling 2000 pictures. Was $45.00 Now 21.80 Machine Sop Pracr,ce, 6 volumes, 2300 . pages, Foremost American and airplane. When he did finally succeed in 2500 pictures. Was $45.00 Now 21.80 making his leap, he was some distance out Steam and Gas Eng,neering, 7 vol., 3300 pages, Foreign Writers over the water, and down he went deep into 2500 pictures. Was $52.50 Now 24.80 Law and Practice (with reading course), 13 vol., the briny waves. He emerged, gasping and 6000 pages, illustrated. Was $97.50 Now 49.80 We have also a limited amount sputtering and was quickly rescued by one Fire Prevention and Insurance, 4 vols., 1500 pages. of the following Bound Volumes of the boats. As he reached the shore, 600 pictures. Was $30.00 Now 14.80 it Telephony and Telegraphy. 4 volumes, 1728 pages, of Science and Invention (Electri- dripping wet and in a pitiable condition, 2000 pictures. Was $30.00 Now 14.80 did not add to his peace of mind to see Sanitation, Heating and Ventilating, 4 volumes, cal Experimenter) : the doctor genially shaking hands with the 1454 pages, 1400 pictures. was $30.00 Now 14.80 Drawing, 4 volumes. 1578 pages, 1000 pictures, pretty girl -bathers who had surrounded him. blue prints, etc. Was $30.00 Now 14.80 Vol. No. 6-May, 1918, to "Well, Silas," exclaimed the doctor, gaily, April, 1.919. "how goes it ?" Silas gazed ruefully at his newly bought Shipped for 7 Days' Trial Vol. No. 7 -May, 1919, to suit of clothing, now reduced to tatters by Pin your check or money order for $2.00 to the jagged framework of the machine, but the coupon and we will immediately ship you any one set of these valuable books. Use them April, 1920. he said nothing. for seven days. Then remit only $2.80 and pay "Never mind, Silas," cried the doctor, the balance at the rate of $3.00 a month -75 Vol, No. 8 -May, 1920, to cheerily. "Christmas is coming soon, and I cents a week. If you don't want the books. drop us a line and we will return the $2.00 you April, 1921.. prophesy that Santa Claus will bring you sent us and send you shipping instructions for a complete wardrobe of clothing, far su- returning the books at our expense. Each volume bound in stiff perior to any you have ever had. Now mark Act now -while these splendid books are being green vellum my words because I pride myself that I am offered- at 20% to 50% less than regular prices. board covered with something of a prophet. Now smile and This offer is open to every person within the and gold stamped. boundaries of the U. S. and Canada. Grasp your look pleasant because there are some movie - opportunity -fill in and mail the coupon now. Price for volume No. 9....$2.25 men here and they want to get a close-up Price for volume No. 6, 7 or 8 2.00 of you. You will go down to posterity as American Technical Society a pioneer of the motorless airplane, for al- DEPT. X-253, CHICAGO ALL FOUR VOLUMES.... 7.00 though this first experiment has failed I feel Sent Express Collect. my machine confident that will eventually American Technical Society, Dept. X-253 open up a new era in the history of flying." Chicago, U. S. A. EXPERIMENTER PUBLISHING CO., I am enclosing $2.00 as deposit for a set of 53 Park Place, N. Y. for 7 days' examination, Gentlemen: THE ULTIMATE COLD shipping charges collect. I will examine the books thor- Enclosed find $ for The absolute zero, the lowest degree of oughly, and, if satisfied, I will send you $2.80 within 7 which send me bound vol. of S. & I. cold that can ever be attained, has been ap- days and $3.00 each month until I have paid the special price of If I decide not to keep No. 6 ( ), No. 7 ( ), No. 8 ( ), proached within less than one degree. the books, I will notify you at once. You will then No. 9 ( ), by express collect. This important announcement was made return the $2.00 deposit I have sent you with shipping recently at a meeting of the Faraday Society instructions for returning the books at your expense. Name at the Institution of Electrical Engineering To Insure prompt shipment till out all lines. in Leyden, Address London by Prof. Onnes, of Hol- NAME land, who in 1908 liquefied the gas helium at Town State a temperature only 4.3 degrees above abso- ADDRESS lute zero: EMPLOYED BY - 1128 Science and Invention for March, 1923

,,,,,,,,,,,11111111,1,.,,,,,,,1,111,1,1111111.,,11111111,1,,,,,,,,,,,,,,1,,,,,1,,,,,,,,,,,,1,111111,111,,,,,,,,,,11111, Measuring° One Mil® ili©nth ofd mn Hnch (Continued from page 1067) MM.., .,..,.,,,,.,,,,MM,,M11111,,,,. ..,MMO.M.,,.,.MMIMMMMMMMMUIlla

to locate our measurement within one tenth The Magic Carpet of a half wave length of light, or one tenth of a hundred thousandth of an inch, in other words, one millionth of an inch. This loca- tion, although approximate, may be made more accurate by varying the thickness of YOU could sit on the fabled carpet of Bagdad the wedge of air by pressure upon the optical flat, so that the distance between two adja- and view the world. In the whisk of an eye- cent bands is greater. In making a test to determine the varia- lash it would carry you any place you wanted to tion between an unknown gauge, and a standard gauge, both gauges are placed upon go. All you had to do was wish. an optical flat and wrung or twisted on its surface, so as to make sure of contact. An- other optical flat is now placed upon them. Advertising is a sort of magic carpet. Read it Consider in Fig. 7 that the unknown block at the left in our illustration, is being com- and in the twinkling of an eye you can review pared with the block of known thickness, at the right. It will be seen that the interfer- the merchandise of the world, pictured and dis- ence bands occur, one-half a band lower on the wedge of the left hand gauge, than do played for your benefit. those on the standard. It is quite evident that if both gauges were of the same size, then any bands which occur on one gauge The advertisements introduce you to the latest would occur in exactly the same position on the other, and therefore, the bands would styles-the newest comforts for the home-the 1ppear to be practically continuous, but in view of the fact that the gauges are of dif- best of the world's inventions. They tell you ferent sizes in this illustration, then the one at the left is five millionths of an inch how to buy, where to buy and when to buy. shorter than the one at the right, its inter- ference band occurring lower than the one They keep you posted on things necessary to at the right by the distance of a half -half feed and clothe family wave length. you and your and make For the purpose of measuring a X inch you comfortable and happy. plug that is not tapering, the gauge block is placed upon the lower flat, and the upper flat placed upon both this and the plug Read the advertisements as a matter of itself, as indicated in Fig. 10. This plug is educa- usually placed a distance away from the tion. Read them and keep abreast of progress. gauge equal to the width or the diameter of the gauge, so that the number of bands may be counted, and if the plug is larger, they may be multiplied by two. The wedge of air increasing in thickness from the point of contact of the upper flat to the end of the gauge, by ten millionths of an inch for every dark band, we can readily count six bands on this illustration. Multiplying this figure by two, we find that the plug is twelve millionths of an inch oversize, or larger than our % inch plug standard gauge. If the plug is undersize, then the bands will directly indicate how much that plug is under size; we do not have to double the figure. Read the Advertisements Regularly In measuring a steel ball, Fig. 8 the same procedure is followed, the number of dark bands are counted, and the diameter of the ball readily 'determined. Of course a stand- ard gauge must always be employed in such measurements. In order to select balls of uniform size, Fig. 9, a slightly different procedure is fol- RADIO PRICES SMASHED lowed, both balls being arranged on a card- We now announce drastic cuts in our quality lines. All board templet a fixed distance away from goods prepaid and sold subject to return for rebate or ex- change. You simply must be pleased. A sample saving !earTone the stangard gauge, and if the lines are par- follows. Order from following or send for full list today. allel to a line joining the center of the two Complete Regenerative Vacuum Tube Receiver FUR Range approximately 1,000 miles Our price Others balls, which line is likewise at right angles Panel of bakellte 7 in. x 12 in. drilled $1.75 $2.50 to a line joining the center of the steel Cabinet of 3 ply wood to fit panel 1 50 2.50 2 three-inch dials (le 35e each 70 1.40 Your balls and terminates midway between them, 16 switch points with nut e Ole 16 .48 we know that our balls are of 4 switch stops with nut (dl Olc 04 .12 skin can uniform size. a binding posts, Nickel plated d 03e 24 .48 be quickly If the bands are angularly disposed, then 2 switch levers (d) 25e each 50 .90 we can determine, by projecting { 1 filament rheostat, High grade 65 1.10 cleared of Pim- lines, as 1 vario -coupler with fourteen taps 2 25 4.00 ples, Blackheads, illustrated in Fig. 9, just how much these 1 23 plate variable condenser 1 95 3.50 steel, balls 1 tube socket of high quality 45 .85 Acne Eruptions on the vary with respect to our gauge. 1 phone and 1 grid condenser na 15c and 20e .35 .65 or body, IO 50 .84 face Enlarged In Fig. 7 the principles employed in deter- feet spaghetti tubing a 05e Pores, Oily or Shiny Skin. 1 tube socket support 15 .25 $1.000 mining these different measurements are illu- 15 feet copper connecting wire 15 .30 Cold Cash says I can clear your 1 set blueprints for assembling 10 .25 Skin of the above blemishes. strated. One can always be sure of his measurements to $11.44 $20.12 RWRIkletTE TODAY for my FREE within an accuracy of a Some other articles taken from our price list are- Boo-" CLEAR-TONE hundred thousandth of an inch. He can Cunningham detector tubes $4.25 $5.00 SKIN"-telling how I cured approximate Transformer -Audio frequency 2.95 4.50 myself after being afflicted for fifteen years. his measurement to within a Frost Aline -2,000 ohms 3 95 5.00 IL S. GIVENS. 168 Chemical Bldg.,11anaes City, Ms. millionth of an inch with very little chance Two step amplifier parts complete 12.95 21.50 RADIO PARTS MANUFACTURING COMPANY of varying another millionth. ltttp Montclair Dept. "8" Detrsit, Miehlgaa Photos Courtesy of H. L. Van Kum. Science and Invention for March, 1923 1129 Do You Want a Real Headset? The Dictograph Radio Headset Is the in the World at Any Price Best PRICE This is the same supreme Dictograph Headset that has always sold for $12-same in quality, same in guarantee, same in everything but the price-$8 complete. Made by the $Q makers of the world standard Dictograph products-the mar- velous "Acousticon" for the Deaf, the famous Detective Dic- tograph, the Dictograph System of Interior Telephones and O the Dictograph Radio Loud Speaker for the Home. Read a few of the many letters we have received from Dictograph The Standard of the World Headset users. You, too, can enjoy the utmost in Headsets if you TYPE R-1-3,000 ohms, for all types own one. tube receiving LAPORTE, IND. of crystal and vacuum u. S. MARINE HOSPITAL, No. 43, "I wish to compliment you on the 3,000 ohm head- sets ELLIS ISLAND, N. Y. market, retailing at $12.00 set you now have on the in "The undersigned has, for the past sixteen years, (now $8). I have been expeibnenting with the Radio Step into your dealer's today, and listen commercial and government oper- game for the past year. In my experience have tried with this supreme instrument. Note the been an amateur, the ator, and has used every known make of radio receiver out 19 different headsets, Including difference ! one of Type which I for 810.50. 1 at last have four,.i on the market. On April 21st your purchased harsh- R-1 3,000 ohm receivers was purchased and it can the ideal phone, where tone quality excels, and Buy two or three Dictograph Headsets and are abso- ness is eliminated, end 1 cannot express myself in be safely said, without dispute, that they obtained." let the rest of the family in on the enjoy- lutely the best radio receivers on the market today, words as to the wonderful results I have ment. bar none."-C. H. West, U. N. P. H. S. J. T. Bachman. Always insist on Dictograph Products THEY ARE FULLY GUARANTEED DEALERS: The Dictograph is the fastest -selling Headset on the market today. Order through your jobber, or write direct for names of authorized distributors. DICTOGRAPH PRODUCTS CORPORATION Suite 1305 220 W, 42nd St., NEW YORK CITY (Branches in All Principal Cities)

Hear the programs of the Broadcasting The RADIOGEM Stations on the RADIOGEM (Y s tents Pending) $1 Receiving Set - The Simplest Radio Outfit 444. Made-Yet as Practical as the Most Expensive! You need know absolutely nothing about wireless to operate and enjoy the RADIOGEM. It is so sturdy, so simply constructed that it is small wonder radio engineers who have tested it have pronounced the RADIOGEM a brilliant achievement. The RADIOGEM is a crystal radio receiving set for everyone ..l..c.__ 7':7 at a price anyone can afford. +` . 1i Why The RADIOGEM Can Be Sold For Only $1 Here's the secret: The RADIOGEM Construed= eliminates all unnecessary trimmings, cabinets and the like, which do not play any part in the operation of a set. You receive the RADIOGEM unassembled, together with a clearly written instruction book, which shows you how to quickly and easily construct the set, using only your hands and a scissor. The outfit comprises all the necessary wire, contact points, detector mineral, tube on which to wind the coil, etc., etc. The instruction book explains simply and completely the principles of radio and its graphic illustrations make the assembling of the RADIOGEM real fun. Remember the RADIOGEM is a proven, practical radio receiving set and will do anything the most expensive crystal set will do. 77 The RADIOGEM is the Prize Winner of the Age Out of hundreds of radio models submitted recently in a great nation-wide contest, radio engineers, the judges, unanimously chose the RADIOGEM as the winner-the simplest radio -re- ceiving set made! And the RADIOGEM costs you nothing to operate: no form of local electricity is required. The RADIOGEM is the wonder item of DEALERS the radio age. It is storming the coun- try, for the RADIOGEM'S price is so low everyone is able to buy one. Write immediately for full particulars before that shop across the street beats you to it.

Receives `The RADIOGEM up to CORPORATION 42-S HUDSON STREET 20 Miles NEW YORK CITY Without Phone or Aerial 1130 Science and Invention for March, 1923

11,,,1111111, An Am . 11fier for Your P2esent °taler By BERT T. BONAVENTURE (Continued fr.ofn. page 1085) lImundmomon,,, mIl,mlumm mm,,,rmmule.. .dunde,1,,,1111111111,,,: two sockets. Using a hard tube as a detec- DO YOU? tor, with higher plate potentials than 221/2 volts, will give almost as good Do you want a sensitivity to save 20 to 40 per cent on all as a soft tube with considerably less tube your purchases of standard radio apparatus? noises. Do you want the personal advice and counsel of the The first point in the design is greatest radio authorities in the country the calcu- problems? in solving your lation of the tuned impedance used in the plate circuit Do you want of the radio frequency ampli- to receive free of charge a quarterly publication fier tube. The giving you a digest of the latest findings of radio science, telling three circuit tuner for which you how to construct and operate both simple and advanced this amplifier was designed had a wave- radio receivers and transmitters, together length useful information? with a fund of other range of from 150 to 650 meters. It is obvious that the impedance should also be able to cover this range. First the ap- Of Course You proximate capacitance values of the con- Then Do! denser must be send us a post -card immediately, asking for Booklet S-1, known. For a 23 plate con- describing our Co-operative Service Plan. denser if the following values are used in the hypothesis, one will not be far off the Ilse %bin averages values: maximum, .00045 mfd., (!uilb, 3Jur- minimum .000015 mfd. In the particular con- Co-operative Service Bureau denser used in this amplifier, the values were .0004275 mfd., and 256 13.5 micromicrofarads WEST 34th STREET respectively as given by capacity bridge New York City measurements. Care should be taken th4 the condenser selected should have low di- electric losses. Condensers with fibre end plates should be immediately rejected, as the losses therein are bound to be too high for use in radio frequency circuits. High losses mean broad tuning with resulting interfer- ence. To calculate the inductance of the coil to be used in parallel with the condenser, the following formul are used: (1) LC = K, with X constant. where L = inductance in centimeters. C = capacitance in microfar- A ads. Telephone X = wavelength in meters. 471-2 a2 n2 (2) L = -K Receiver b for where L = inductance in centimeters. The RADIO INDUSTRIES CORPORATION a = mean radius of the coil have been manufacturing their famous RICO in cm. TRIPOLE RECEIVERS for some time for radio b purposes. These = length of coil in cm. phones are made regularly for n 1,000 and 3,000 ohms. There has, however, been = total number of turns in a very large demand for a low-priced the coil. ' Receiver. 75 -ohm The Corporation has finally decided to 2a place one upon the market at a price that every one can afford. K = factor varying as -. 415 A TRANSMITTER AS A RECEIVER Lb SEND COUPON Now AND GET THE BIGGEST (2a) n2 = .. . transposing (2). DOLLAR Buy THAT You HAVE EVER SEEN! 47r2a2K Formula (1) gives the oscillation For 75 cents additional, we furnish constant a single head -band with the 'phone. Has regulation soft squared of the circuit, when the rubber covering. Will not tire nor hurt you, wave length even if worn for hours. is known. Take 650 meters as the mum maxi- PRICE LIST of Other Receivers We Manufacture wave length that is desired to be re- No. 20 2000 ohms Double Head Set $5.00 No. 15 1500 ohms ceived. The LC value No. 30 3000 ohms Double Head Set Single Head Set 3.25 for this particular No. 40 4000 5.50 No. 2 1000 ohms Receiver only wave ohms Double Head Set 9.50 $2.00 length is 119. (See Lefax No. 10 1000 ohms Single No. 3 1500 ohms Receiver only 2.25 sheets for Head Set 3.00 No. 05 a table of 5 ohms Receiver only 2.00 these LC values.) Knowing the I maximum Radio Industries Corp., 131 Duane condenser value, .0004275 Gentlemen:-As Street, New York City. micro - per your advertisement, I enclose herewith farads, we may now M. O.) for $ (Check, calculate the inductance for which please send me at once RICO 75 -ohm required Receiver(s) and Head-band(s). to tune to this wave length, making D You agree to send these to me all charges prepaid. use of (1). g\ Also, please send me your Illustrated literature and information tour $350.00 Prize Contest. about LC= 119 INDUSTRIES NAME or L X 0.0004275 = 119. L CORPORATION STREET = 119/0.0004275 X l0' ... when L is 131 CITY STATE in microhenries. Duane Street, New York S. & I. 3-2:3 . . Therefore, L = 278 microhenries. Now, let us see if this value of inductance is small enough to tune to the minimum wave MAKE BIG length, assuming it to be 150 meters. PROFITS CHARGING BATTERIES LC for 150 HB Csera clear meters is 6.35. Whence $150 to $300 every month from new HE a -Hour the Battery Charger. Charges auto batteries minimum LC of our coil while old perfectly to 8 hours, and condenser systems take 2 or 3 days. No experience needed to oper- should be ate. Start your own money -making 6.35 or less in value, preferably 'viryi a9ttEa battery charging business NOW. $30 Monthly Pays for 8 -Hour less. Substituting ,IIlliti'd Small Battery Charging the minimum condenser cash payment brings outfit on trial with money -bark guaran value in tee. Easily pays for itself from your big (1) solving we get the first monthly profits. Be in your town to offer 8 -hour battery charging. Get this LC = K or 278 X 0.0000135 X 10' big business, beat competition. Write today for Information. = 3.75 This figure corresponds 115 HEasy TROY, to meters, so Monthly BTerm.sCCAbsoluute Satisfaction that our coil is capable of covering from to 115 650 meters. Actually these values will be Science and Invention for March, 1923 1131 somewhat higher due to the capacity be- tween elements of the tube also being across the coil. That is why the coil was designed un 111_ to go as low as -115 meters, so as to allow qlMll !Illh'IIIlAlI11111Ullllll UII ' ' ' ' . II!Äl11NIu111I!Illï'q1L'!IIIIpV' for the plate to filament capacitance of the ` I '))i1 ! `Fódr d b`,p tube. d Let us now take up the actual winding of the coil, using formulæ (2) and (2a). For- 0*h% mula (2) is merely given as the starting point from which (2a) is obtained, the latter eed giving the number of turns of wire for a required inductance. The factor K may be obtained from Bucher's Wireless Experi- menter's Manual or from Bulletin 74 of the Bureau of Standards. The particular coil used in this set had a diameter of 2/ inches and was 1% inches _ ' , .,; long. It was decided to let the depth of the winding be % inch long, since litzendraht wire was used in winding and banked in two _ ... . layers to save space, the rest of the coil being used for mounting purposes. Allowing for Rece:ae the new some distributed capacity of the coil, it was broadcasting on found that an inductance of 250 microhen- 710 meters and 99 higher wave -lengths ries would be sufficient for our purpose. with the "Multi- Range" coupler. Wave- Calculation of n. length range -170 .to Lb 3400 meters. (1)...7r2= Coupler Permits the easy construction 471 -2 a2 K of complete radio receiver at low cost. L = 250 microhenries. Price $11.00 "The finest bank -wound coupler ever 1"=2.54cm. From Your Dealer produced." N. Y. Even ing Mail h=2x%= or Direct Laboratories. - a = 2.625/2 = 1.3125" = 3.34 cm. a2 = 11.12 K = 0.46228 RG 510 250 x 103 x 2.54 The New Radio Guild Radio -Audio Frequency n2 - Complete Receiver of Unequalled Excellence 4 x 9.87 x 11.12 x 0.46228 and Efficiency n2 3128 and n 56 turns. The RG -510 is the "Distance' receiver you have been look- Whence = = ing for. With the small loop aerial supplied with each set it wound with 56 is just as easy to pick up stations a thousand miles away as the The coil was therefore near -by stations. Receives hundreds of miles without loop, aerial, turns of No. 38-10 strand litzendraht wire, ground or any connection whatsoever. Extremely simple to operate by measurement, and unusually selective. Designed by experts giving an inductance actual in radio frequency amplification. Operates on of 257.5 microhenries, a value which is suffi- one, two or three stages of audio amplifica- ciently accurate for our purposes. tion. the rest of the WRITE FOR FURTHER PARTICULARS With this coil constructed, OF THIS REMARKABLE SET assembly is purely a matter of a little man- ual labor. The frame on which the sockets, List Price, $195.00 transformers, and binding posts are mounted Dealers: Your customers will be more than is made of 3/8 -inch angle brass, with the satisfied with this set. Write for discounts. corners strengthened. In bending the brass at the corners, cut out a right angle tri- angle from the point where the bend is 04r badin (!uttd, Jnr. 256 West 34th Street New York City made. This prevents bulging of the stock Specialists in RADIO FREQUENCY AMPLIFICATION when the bend is made by allowing the Manufacturers of the "VOX HUMANA," "BROADCAST RECEIVER" and "DASH- ends of the cut to come together. Strengthen BOARD SPECIAL." Distributors of DX RADIO FREQUENCY TRANSFORMERS this joint by soldering an oblong -shaped piece of brass on the inside of each corner, using care to make a neat job. The dimen- r,.,%` sions of the bends are given in Fig. 2. The dotted line shows where the strengthening :11üÌuilrel '111111111DhR1111111111111111111i11111111IUlllllmlmmU(111111IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIiad1I1111Rtnua pieces are to be soldered. All dimensions given are optional with the constructor, as he can follow his own personal taste. Two of these brackets are made, exactly alike, and are held firmly to the panel by HELP WANTED means of four No. 8/32 machine screws through each leg. The cross -pieces at the al.. -!--111--5__ RA I LWAY en ..t.. m ...... 1111...'--.11p1-J-..1111...!...IY..5...1111..-1._ top and bottom are made of the same 3/8 -inch n! se I angle brass and are fastened to the brackets ,,.,... onvmmum, nnunnnur by 6/32 machine screws. Care should be II IIIIIIIIIIIiI IIII III IIIIIWIIIIIilipmlt'Imi III` taken in drilling and tapping the holes for these screws, due allowance being made for ,;>, :¡ r'ï iil"l' IIIIIIIIIIÌIIIIIIIIII _::,fl the thickness of the brass stock when punch- i:.rj"i"îrl' _ir. I i ing the centers prior to drilling. _i- This rigid frame -work supports the four MAIL CLERKS sockets, the two transformers, the binding $1600-$2300 Yearly post strip Railway Mail Clerks, City P and the plate impedance inductance Become Carriers, FRANKLIN INSTITUTE. Dept. P182 coil. A single strip of % by 3/32 -inch brass Postoffice Clerks, Customs and Internal Rochester, N. Y. was cut long enough to accommodate the Revenue Clerks. Kindly send me, without any obligation whatever sockets on my part, and entirely free of charge (1) a full when they are placed side by side. description of the position checked below; (2) Sam- The sockets are mounted on this strip, which Railway Mail Clerks Have Pleasant ple examination questions; (3) Free copy of copy- righted book, "Government Positions and How to is then fastened to the frame with two 8/32 - Work-Travelling Continually Get Them"; (4) A list, of U. S. Government Jobe inch machine screws, one in each bracket, obtainable; (5) Tell Me How to Get the Positions Government positions have yearly vacations Checked. mounting the strip high enough suffi- to give with full pay. Promotion to Big Pay positions .... Railway Mail Clerk ($1600- 2300) cient 1800) clearance above the transformers. This is very rapid. The position is not affected by ....Postoffice Clerk is done to facilitate .... Postoffice Carrier ( 1400- 1800) wiring to the transform- strikes, poor business conditions or the whims ....Rural Mail Carrier ( 1800. 2600) ers, and care should be taken not to place the of some petty boss. Name sockets too high, otherwise the tips of the tubes, when placed in the sockets, will pro- DON'T DELAY Address Use This Coupon Before Tou Mislay It. trude from the top of the cabinet and pre - Every boy or man 18 or over should send coupon at once WRITE PLAINLY P182 1132 Science and Invention for March, 1923 vent the closing of the hinged cover. The two views of the rear of the amplifier show .1 Resolution in Radio Receiving these points clearly. The transformers are mounted directly under the tubes into which RADIO they feed, with the secondary leads nearest NATIONAL AIRPHONE Down the tube. In wiring the transformers, make sure that the outside lead of the secondary GOLD GRAIN DETECTOR a Month winding goes to the grid and that the out- Guaranteed Fool -proof side of the primary winding goes to the Brings Joy to Every Crystal User plate of the preceding tube. These leads An Absolute Necessity are the high potential side of their respec- For All Crystal Sets tive windings and have a lower capacity to ground than the inner leads. This capacity PRICE effect increases with the frequency, tending $2.00 to distort high pitched notes, which deleteri- Actual Size ous effect is minimized by observing the with Brackets above and screws for FAMOUS precaution. panel mounting. Mount the transformers directly on the This Detector frame, at right angles to each other, using is not a fixed braces to give rigidity. This connects the detector but a liIlr cores to revolving o n e - LONG-DISTANCE the frame work which will be later Instead of a cat - grounded to the negative side of the fila- whisker, several ment, which connection may be seen in the hundred grains Regenerative of pure gold are lower right-hand corner of the photograph used for contact. Radio Receiving Set of the general view of the rear of the Is always ready Built by Trr City Radio Electric Co. (Licensed under amplifier. In mounting the condensers, no and Stays - Put. U. 8. Patent No. 1,113,149 and pending special means Most sensitive Letters Patent No. 807,388) were taken, since they are so point of the The "Sensitone" brings in concerts, bands, light that the bus bar wiring is sufficiently detector is found lectures, market, crop and weather reports, strong to support their weight. The disposal by revolving the sacred services and sermons, bedtime stories of these For Pastel Mounting cartridge slightly for children-all the wonderful programs of condensers may be seen from the (Patents Pending) while tapping. your pick of all the 500 broadcasting stations photograph. The grid leak is mounted di- in the U. S. and Canada. rectly on the detector tube socket, using the After you have fussed with cat -whiskers, "Sensitone" Set is complete-including bat- spring springs, balls and adjusting handles, and teries, tubes, head -phone, antenna, wiring- clips taken from a standard grid leak after you have become almost a nervous connections-everything you need, ready to mounting. As to the binding post strip, wreck hunting for the "elusive spot." install, is equal to sets now sold at $150.00 PA by 3/32-inch brass strip was bent into you will welcome with open arma our to $175.00, yet our price is only $95.00. the shape Set is shipped on receipt of the first $15.00 seen and fastened with 8/32 -inch 100% FOOL - PROOF payment. You are dealing with a respon- machine screws to the bracket on each side. sible, old -established House. Ask any banker The rest of the apparatus layout followed "GOLD -GRAIN" DETECTOR or business man to look up our rating in Awarded certificates of Merit by Insti- Dun the dimensions of the front of the Tae -inch or Bradstreet reports. tutes of New York Eve. Mail and New Only a limited number of "Sensitone" seta panel, as given in Fig. 3. York Tribune. will be sold on this easy-pay plan. Fill out It is advised that the outer ring of peep- coupon and attach check or money order Airphone for $15.00. Circular free. holes be omitted. They were drilled in an National Outfit $12.50 endeavor to balance the panel by having the Harold R.Wakem Co. diameter of the net work equal to the diam- 849 W. WASHINGTON ST., CHICAGO, ILL. eter of the condenser dial, but it is believed that the panel will look better if the outside HAROLD R. WAKEM COMPANY, 849 W. Washington Street, ring be left out. Drill the panel from the Chicago, Ill. face side; to prevent chipping on that side, CORPORATIRP"e Enclosed you will find $15.00 as first payment, countersink peep REG. Vs PAT Oro upon receipt of which you will send me your com- the -holes slightly. All the plete Sensitone Radio Receiving Set, as described brass parts of the amplifier were nickel - 16-22 HUDSON STREET above. 1 agree to send you $10.00 every thirty plated NEW days thereafter, Until the full purchase price Is paid. to produce a commercial appearance, YORK This set Is to remain the property of Harold R. but it is optional to go through Dealers-Write for Prices Wakem & Co., until payments are completed. this trouble, though it does give a business -like effect. Signed It is Street Address City advised that the connecting bars used In the spaces below give the names of two refer- to strap over to the tuner unit be nickel - ences, banks or business houses preferred. plated, as it will considerably improve the Name and Address general appearance of LOUD Name and Address the set. SPEAKER FOR ANY In operating the complete set, proceed to CRYSTAL SET tune the receiver as usual, at the same time The STEINMETZ Amplifying Unit now selling tuning the plate circuit of the radio fre- for $8.50 will enable you to hear your crystal quency tube by means of the condenser. If set all over the room. oscillations commence, bring the potentio- No Storage Battery Required Our Genuine Skinderviken meter adjustment into play, ALL STEINMETZ EQUIPMENT which will IS Transmitter Button throw the grid of the tube sufficiently posi- THOROUGHLY GUARANTEED tive to stop the oscillations. The dial of Steinmetz 3000-ohm Phones . $6.50 Used by the condenser may be Steinmetz 2000 -ohm Phones . $5.00 thousands for calibrated to read directly in wave lengths, or a chart made Steinmetz 1000 -ohm Phones . $1.75 Wireless, Loud of the wave lengths corresponding to the Equal to any $10.00 or $12.00 phones made. Speakers, different positions of the Complete Catalogue FIVE (5) CENTS Am- dial. When this at your dealer plifying and all is done the tuning is simplified considerably or as the condenser is set for a particular wave Steinmetz Wireless Mfg. Co. sound transmis- and left there, the rest of the tuning oper- 5706 PENN AVE. PITTSBURGH, PA. sion purposes. ations being performed as though the radio Price $1.00 frequency tube did not exist. POSTPAID All the broadcasting stations in the vic- with instructions inity of New York can be heard with suffi- Free Literature cient volume on a loop, using the amplifier alone, and with a good outdoor aerial con- l.lr'/7 1 -Ii!/i!t siderable long `lil'2-rersesaur._r-iji 1 K. ELECTRIC CO. distance reception is possible, 15 PARK ROW NEW YORK depending, of course, on the type of tuner Here's your opportunity. Radio needs used in conjunction with the amplifier. you. Win success in this fascinating field. Trained men in demand at highest salaries. Learn at home, in your spare time. A ONE -OUNCE TYPEWRITER A typewriter weighing one ounce and fit- Be a Radio Expert CUT RATE I will train you quickly and easily, to design RADIO ting in a vest pocket has been built by Dr. construct, install, operate, repair. maintain, and STANDARD APPARATUS ONLY H. E. Wetherell of Philadelphia. sell all forms of ltadcoagparatus. My newmethode Write for 54 -page Catalogue of Bargains He de- are the most successful in existence. Learn to earn BALDWIN vised it for TYPE "C" PHONES . $10.25 his own use. BRANDES SUPERIOR $1,800 to $10,000 a Year PHONES . . . $6.45 Held between the fingers and RADIOTRON U V 200 DETECTOR TUBES . $4.25 upon the home -construction, tube ACME AUDIO TRANSFORMERS 53,75 paper, the machine writes by means of a FREEWonderful,receiving set, of latest design. Everything for Radio at less. Immediate Delivery. wheel equipped with rubbing letters Writefor"Radio Facts" free. Engineer Mohaupt FEDERAL which American Electrical Association RADIO ELECTRIC CO. special devices bring in contact with the Dept. 63 4513 Ravenswood Ave:, 1233 GRAND ChiCaap AVENUE KANSAS CITY, 110. paper. Science and Invention for March, 1923 1133

..1,,,,,.,,,,11.,.,,,,,1111,11,,,11,,,1,,,1,0,,,,,,,,,,,,,1,11,,,11,,,,,,,,,-,,,,,,,1,,,,,,,11,11,111 11,,,,1,,,1,,,,1,,,,,,,,,11,,: Talking Across the Atlantic (Continued from page 1080)

The new system used in the trans -Atlan- tic tests is quite different. Since it is pos- sible to build a receiving set such that it is unnecessary to transmit the carrier wave this can be entirely suppressed and is suppressed Catalogue in the new system. The energy which would otherwise go to it is assigned to the side - bands thereby doubling their useful power. This is not the only notable feature of the new circuit. When both side bands arc FREE transmitted our diagram shows that the ether One copy of this complete Catalogue of is called upon to carry a band of frequencies Radio Outfits, parts, Dictionary of Radio 10,000 cycles wide, extending from 45,000 Terms, Instruction Book, and Guide to cycles to 55,000 cycles. Now the transmission Successful Radio Work-one copy is of either side band alone is all that is neces- yours Free. sary and as good results can be obtained Simply write us a post card and we by suppressing one side band and assigning will mail the complete book to you Free, its high frequency energy to the other. It by return mail. is evident that by the suppression of one side It quotes the lowest prices, amaz- band it becomes possible to transmit twice as ingly low prices on everything for the many messages through the ether at one expert and the amateur. Every im- time as would otherwise be possible. proved part, the most up-to-date out- In the present tests this frequency is fits, everything that is needed of the 55,500 and corresponds to a wave length of most modern type-at the lowest 5,400 meters. possible prices. It gives a list of broadcasting stations, and 55000 All hSgh frequency energy is gives much information about radio construc- Upper side - Corner locoted m one side -bond. tion and operation. Every one interested in wove bond corrs- ing speech Radio needs this complete catalogue and book Corner frequencyis suppled of instruction. f 50.200 50.000 Lower side- 49,800 bond corry. Why Pay Higher Prices? ng speech Montgomery Ward & Co. has for fifty years dealt on a 45 000 Money -Back basis, absolutely guaranteeing everything t they sell. With quality absolutely assured, why pay higher prices elsewhere? Write today for this Free Radio Book and see for yourself the Saving le will bring you. One copy is yours Free. You need only write us a poet Large card. Selection of Write to the house nearest you. Address Dept. 40-R. 5000 Outfits Chicago KansasCity St. Paul Fort Worth Portland,Ore. Speech Speech 200 Before After Trans- Defection from detect comes o, modulation modulation mission ion speech Graphic chart showing how trans -Atlantic radio- ìntg OnWard phone, transmitting wave energy, is confined to is Progressive B one side -band, as explained in the accompanying e, The Oldest Mail Order House Today theMost text. differs from the usual The present system RADIO "A" & "B" STORAGE Batteries CHARGED At Home For Few Cents With radio transmitting systems in another im- "PATENTED FULL WAVE" 100-130 Volt 60 Cycle A. C. Automatic Magnetic portant respect. The usual type of trans- Eventually You Will Buy An F -F REC. mitter sends out, in addition to the group the mes- TIFIER. Why Not Now: The Sooner of waves which does not comprise You Buy It; The More You Save. sage, two groups each of which does carry -F RADIO RECTIFIER It CHARGES All 6 Volt RADIO "A" & AUTO Batteries: & ALL RADIO "B" & LOUDSPEAKER Storage Batteries Up To 120 Volts the message. In the new apparatus only one In Serles Inductively At Home Overnight. Disconnecting & Multiple Connections Unnecessary. Charging Circuits Separate. of these groups is radiated. This makes pos- Nothing Like It Made. No Chance For Grounds Or Short Circuits. No Skill Required. AMMETER Eliminates Guess Work. It Costs You Less To Buy An F -F RECTIFIER Than To Be Without One. You PAY For ONE Whether You Buy One Or Not For It Costs sible the sending of twice as many mes- An Average Of $2 For Charging & Rentals Every Time An Auto Battery Is Charged By Others, But Only A Few Cents When You sages at the same time without interference. Charge Your Own From A Lamp Socket With An F -F Battery Boosting RECTIFIER. If You Have Never Known The Delightful Feel This feature is particularly important at long Ing Of Having Your Storage Batteries Always Fully Charged For RADIO & AUTO You Will Experience A New Thrill When You Have An F -F RECTIFIER Which Gives You A Fully Charged Battery Overnight At A Cost Of A Few Cents And A Pleasant Feeling Of wave lengths where fewer messages can be Things Well Done. Those Who Own Them Feel Their F-F RECTIFIER Is Their Faithful Friend. It Charges Automatically & carried simultaneously than at short wave Being Clean Can Be Placed Anywhere. Nothing To Slop Over, Be Filled, Burn Out, Need Attention Or Cause Trouble. Both Waves Are lengths. The present system was perfected Rectified Thru Infusible Carbon Rectifying Brushes, Maintaining Constant Efficiency Uninterruptedly. While Its FULL WAVE Delivers RAPID TAPER CHARGE Recommended By All Storage Battery Manufacturers.The F -F RECTIFIER Is A Complete Compact in connection with the so-called carrier tele- Portably Handy Charging Unit. Delivers Service Day & Night Automatically & Will Charge A Dead Battery. Do Not Think Battery Is phone which is now in use in this country on They Also Dead & Worn Out Simply Because It Will Not Start Your Car. Buy An F-F RADIO certain long distance telephone lines. Charge RECTIFIER & Fill It With LIFE. It SAVES MORE Than Its Cost & Lasts Lifetime. AUTO Leave Your Battery In Car, Or Wher Ever It Is, Without Even Disconnecting It. Mr. Thayer and the others who spoke to Batteries Screw RECTIFIER Plug In Lamp Socket, Snap RECTIFIER Clips On Battery England Sunday night used a telephone lo- Overnight Terminals; Turn Switch & Battery Will Be Charged In Morning, At Cost Of A Few cated in the offices the American Right In Cents. Is It Not Gratifying To Be Ready For All RADIOPHONE BROADCAST of Tele- Your CAR Music, Sermons & News When Friends Call? Never Having To Be Careful Of, Or phone and Telegraph Company at 195 Tell Friends Your Batteries Are Dead & To Feel Your Car Respond Like A Broadway. This telephone instrument was Greyhound, Spinning Engine With Power When You Throw In STARTER? connected to the radio equipment at Rocky Fully Charged Battery Starts Car Quick & Requires Fewer Expensive Replacements $ 2 0 INSIST on The F-F RECTIFIER. Built By A Master Of The Art In 7 Types. Point by a telephone circuit about 70 miles So Many ThousandsAre Being Sold It Has Made Possible These POPULAR PRICES. long, half of it being underground cable TYPE 8 Charges 8 Volt Radio"A"& Auto Batteries At 6 Amperes $15 and half open wire and connecting tele- TYPE 12 Charges All 12 Volt Batteries At 5 Amperes $15 phone repeaters and equalizers of a type TYPE B Charges All Radio "B" Storage Batteries Up To 124 Volts $15 TYPE A-B Is A Combination of TYPES 6 & B $20 similar to those used on long distance tele- TYPE 166 Charges Ali 6 Volt Batteries At 12 Amperes . $20 phone lines. See picture diagram. TYPE 1612 Charges All 12 Volt Batteries At 7 Amperes .. . $20 The distance from Rocky Point to New Patented Combination. TYPE 1626 Is A Combination Of TYPES 166 & 1812. $28 Southgate is about 3,400 miles. to CHARGES "A & B" RADIO & AUTO BATTERIES. ALL TYPES But "B" ALSO CHARGE AUTO BATTERIES. Prior the The Lower 3 Are Large TYPES Built For Heavy Batteries Or Where Charging Time Is Limited. SHIPPING WEIGHTS Complete With tests of Sunday evening, other tests were AMMETER & BATTERY CLIPS 11 to 15 Lbs. Purchase From Your DEALER Or Mall Check For Prompt Express Shipment. If made to measure the transparency of the Via PARCEL POST Have Remittance Include Postage And Insurance Charges Or WRITE Us To Ship TYPE Desired C. O. D. atmosphere radio Other F -F Battery Boosters Charge Batteries From Farm Lighting Plants & D. C. Circuits & For GROUP CHARGING Economy to messages over such Use Our 8 Ampere 12 Battery Capacity Automatic Full Wave F-F ROTARY RECTIFIER Described In ROTARY BULLETIN 12A. great distances. Measurements were also ORDER Now Or WRITE Immediately For FREE Descriptive RADIO & AUTO BOOSTER & ROTARY BULLETINS 12A & 12. made to determine the strength which the General OFFICES & WORKS: CLEVELAND, OHIO, U. S. A. signals received in New Southgate must FRANCE MFG C O.O Canadian Distributor: The Jack V. Elliot Co. Hamilton, Ontario, Canada. have in that station in order to be clearly heard above the noise of static and HAVE YOU SOMETHING TO SELL OR EXCHANGE? & Invention will reach over 160,000 at a cost of only 12 cents a word interference from other radio stations- For I A Classified ad in Science r 1134 Science and Invention for March, 1923 the purpose of these tests large numbers of disconnected, single words were transmitted. USE A C H Read This The use of disconnected words constitutes an unusually severe trial of any telephone SHARP TUNER DIALS system. In ordinary conversation, the con- tinuity supplied by the thought is a great NEW BOOK aid to the understanding of each word. It ON is intended to continue these measurements over a sufficiently long period of time to supply the most reliable data. Super - Regeneration The measurements thus far made serve to BY indicate that the transmission at night is better than during the day. The strength KENNETH HARKNESS of signals received during the night may be hundreds and even thousands of times stronger than those received during the day. However, it has been found possible to THE CONSTRUCTION transmit AND OPERATION telephone messages satisfactorily OF during daylight, provided interference is not SUPER REGENERATIVE too great, and when sufficient power is em- Your Choice of RECEIVERS ployed. Rough tuning with dial or one thousandth of By Kenneth Harkness an inch in either direction with the Sharp Tuner ..nno,1nocnon unnllnnommoncnnnnnnmmngnnmmnnnrrennnmmtnmmnnnnmmnemmtnu Knob. Both controlled by center Knob ST. With an Introduc- Eliminates a vernier condenser. Locks instru- tion by Dr. Henry Secá ecy ment automatically. Dial grounded, reducing Smith Williams in Radio body capacity. t4 Last Yes! They can be installed on any Receiving Set, (Continued front page 1082) making difficult tuning easy.

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 1 1 1 1 1 1 1 1 1,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 1,,, 111 1,,,,,, 11 1, 1, 1, 1, .,,;E Guarantee an inch apart. Upon the periphery of each If purchased direct and you find the ACH Dial does not warrant your own personal award of disc, are figures from 0 to 9, those on the merit, return it and we will refund your money. extreme right hand disc signifying units, What better guarantee can we give? illlie Edda euilb, Jnr. those next tens, next hundreds, and so on. Regular fitting 5/16" hole, 1/4" and 3/16". 256 West 34th Street The left hand disc corresponds to hundreds Bushings, 5c. each extra. IOc. for all. New York, N. Y. of thousands. The discs turn together upon Price of ACH 3" Dial Complete $2.50 their shaft, and their position in relation to With ACH Condenser 4.00 ACH Condenser each other may be changed at will. By without Dial 2.50 means of a series of pawls, electrical cir- Free Plan with mail orders on request. 48 pages, 30 photographs, wiring dia- cuits are closed, and the cylinder is controlled through a A. C. HAYDEN grams and mechanical drawings. The space of six seconds, whereupon the starting and stopping times of the cyl- RADIO & RESEARCH most complete book on the subject inder are repeated. CO. ever published. Explanation of the The following BROCKTON, MASS., U. S. A. explanation may seem Mail Orders theory of super regeneration is a reve- rather complex, hut upon careful study of sent prepaid in U. S. A. lation. the same, and referring to the accompany- ing photograph and diagrams, the reader The Minneapolis Daily News Says: will obtain a very good idea of how the ap- "Radio books have come and gone in plenty. paratus works. None has seemed to be worthy of special mention. One came this week, however, The unit of time is one second, and the which absolutely demands mention, not to say braise, by its merits. It is THE CON- unit through which the cylinder rotates, is STRUCTION AND OPERATION OP SUPER 20/30, or 2/3 of a second. REGENERATIVE RECEIVERS by Kenneth After the cylin- CRYSTAL -f RECTIFIER Harkness." der has revolved during its allotted space MULTIPOINT of time, 1/3 of a second is SEND FOR YOUR COPY TODAY left to com- (Patent Pending) plete the unit of time. is lag PRICE 50c It this that is A Synthetic CRYSTAL DETECTOR, made use of by the six revolving discs, sensitive over its entire surface. which distribute this time throughout vari- Eliminates all detector troubles. Extraordinary clearness (fit fie Ra in (! ui1b, 3nr. and volume. Endorsed by Radio experts and press. Sold ous parts of the six seconds which they con- in Sealed Packages only. Join the ever increaeing Rusonite DEPT. S. trol, thereby making the message undeci- fans. pherable to anyone who Price, Postpaid, mounted. 256 West 34th St., New York, N. has not a similar Sensitiveness guaranteed... 50c Y. apparatus, and the key number. RUSONITE CATWHISKER For our illustration we will take the code 14 Karat Gold Multipoint Contact or key number to be 687,943. This number 25c.5c. is used in connection with the number Order from your dealer or direct from us. 000000. The process gone through is now RUSONITE PRODUCTS CORP. somewhat as follows. Subtracting 6 from 15 Park Row, N. Y. Dept. "S" 10 we have 4. Each second is divided into thirtieths, and from the above we have that the first period of quiet is 4/30 of a second long. This may be clearly seen from OTHERS ARE DOING IT our Radio the diagram shown herewith, in which the WHY NOT YOU? heavy lines denote time of revolution. Now Your Spare Time Is Worth Set Work Better the cylinder revolves 20/30 of a second. Perfect reception can be had only One Hundred Dollars when wire connections are Now we have 6/30 of a second left in the Per Month soldered. first Everywhere you can secure yearly SOLDERALL and a match make second. This is again a period of quiet. subscriptions to perfect joints guaranteed equal to In the wire or bar solder.- next second the code number is 8, PRACTICAL ELECTRICS At Leading Jobbers and Dealers or which subtracted from 10 leaves 2, or 2/30 SCIENCE AND INVENTION and sent Postpaid for 25c a tube. of a second quiet. Again the cylinder ro- RADIO NEWS SOLDERALL CO. tates for 20/30 of a second, and remain- Every Community is good Dept. S. Newark, the territory N. 1, ing part, or 8/30, is a period of quiet. So it for our solicitors. Thousands of sub- SOLDERALL goes for six seconds, the various time scribers are waiting to give in their v,A Metal in Paste Form periods being distributed as shown in the renewals. p diagram. At the end of six seconds, the Remember-we pay the process is repeated same big until the message is fin- commission for renewals as for new ished. Obviously, 999,999 combinations are subscriptions. Radio Headsets possible. 3000 OHMS SUPERSENSITIVE Send today Guaranteed One for order blanks and Year A message received by a regular Belin sample magazines. machine All will be sent not equipped with the Crypto, if without one cent of expense to you. Price, $3.98 it is transmitted with the use - Plus 20e postage-Total, $4.18 of the anti Write to C. J. Wolfe Dealers wire for sample capturer, would result in a series of irregu- larly spaced dots, which would have ab- EXPERIMENTER PUBLISHING CO. Ernest Electric Co. solutely no meaning. The space between 53 Park Place, N. Y. 4847 Easton Ave. St. Louis, Mo. the revolutions may be changed, so that it 1135 Science and Invention for March, 1923 would be practically impossible for any operator to guess the code number, and therefore the system is very nearly perfect. HARGE. The inventor however, has provided for eibar+ even such emergencies, and by means of a separate disc and contact causes signals to RADIO be sent out during the time that the cylinder BATTERY is stopped. These signals are separate and distinct from the transmission of the mes- A NICKEL sage, but to a listener -in would seem to be part of it. Of course, it is obvious that the actual FNJOYABLE concerts use of the Crypto must be limited, but under certain conditions its use would be invalu- and maximum receiving able. In war times, messages could be sent range are obtained only from the commander of an army to his sub- when your battery is fully ordinates without the least possible chance charged. of interference or detection. Communica- tion between banks could be carried on re- garding stock matters without divulging their secrets. It is reported that a certain HDMc'iiRGER European nation has placed its order for the apparatus to be installed in its State charges your "A" or "B" bat- Department and its Embassy in an impor- lis Corn , inatón a nickel tant foreign capital. tery over night for This apparatus, which is the latest of M. Completes any RADIO it from your without removing Belin's inventions, has been greeted with RECEIVING living room. No muss - no acclaim by European scientists, and will SETS trouble - no dirt - requires no doubt, he received with the same welcome no watching. in this country. After the concert connect to A any lamp socket, snap the Radio for the It clips on your battery and TO own a good receiv- in." While you sleep the eginner Mag' "turn PERRY ing set without HOMCHARGER is silently By ARMSTRONG navox equipment, is like charging your battery, the (Continued front page 1083) having your house prop- charging rate being governed lo,,w,,,,,,,,,, ,,,,.,,,,,,,nrmIllunInunuommunn,,ld,,,,,,,,.11.1.,1111.1111111111,1.1111,,,11113 erly wired and then using automatically. In the morning run the chance of their ruining a highly sen- only small, feeble candle- it is fully charged. No OTHER sitive one that cost a lot of money and that power lamps in the charger can boast of might be put out of commission in the first battery scrap for its possession. The phone with sockets! such quick and economical the mica diaphragm has an arm attached to Whether placed in the aver- performance. the diaphragm that may be broken off if the age living room or large dance phone is even dropped to the table. The hall, Magnavox Radio floods The HOMCHARGER is point of attachment is so critical that it is the desired area with clear, com- said that only an expert should attempt to resonant music or speech-its the only battery charger controlled all of these NECES- make repairs. volume perfectly bining amplification from the Magnavox Power With a receiving set that has spe- SARY HOMCHARGING enough to bring in everything the operator Amplifier constructed features: SELF - POLARIZ- wants to hear in good volume, the ordinary cially for it. give results and ING FIVE TO EIGHT types of phones satisfactory R - 3 Repro- - up under Combination charging they are strong enough to stand and 2 stage Power AMPERE rate- With such a re- ducer any reasonable demands. Amplifier (as illustrated). UNDERWRITERS' AP- ceiving set I have found it necessary to de - PROVAL beautifully fin- tune slightly, or reduce the amplification, in - R-2 Magnavox Reproducer ished in mahogany and old order to get satisfactory results with highly ut- A very strong current with 18 -inch horn: the sensitive phones. power, gold - UNQUALIFIEDLY vibrates the mica diaphragm too power- most in amplifying OVER rasping sound for store demonstration, GUARANTEED. fully and the result is a harsh, halls, 60,000 NOW IN USE. instead of clear speech or music. But if large audiences, dance the incoming currents are apt to be weak. etc. Sold complete with ammeter, the most sensitive phone in my outfit is R-3 Magnavox Reproducer and none too good. with 14 -inch curvex horn: etc., by all good radio homes, offices, etc. electrical dealers for $18.50 The materials used in the ear -piece are ideal for worth considering. The cap is usually of ($25.00 IN CANADA). hard rubber, or something that resembles it. Model C Magnavox Power The rest of the case may be either metal or Amplifier insures getting See the RADIO HOMCHARGER rubber. Metal will stand more banging but the largest possible power D&J.UXE at your dealer's or write it may rust. A metal head band may rust imput for your lvtagnavox direct for our FREE circular showing also, if it is not covered. A leather covered Reproducer. 2 and why the HOMCHARGER is the BEST head band may outwear a cloth covered 3 stage one or, if subjected to heat, it may dry out battery charger at any price. Magnavox Products can be had of and crack. Phone cords may be well or good dealers everywhere. The HOMCHARGER poorly made. If the tips are soldered on, MOTORMOTORISTSISTS1 will also charge your the solder may have burned the insulation The Magnavox Co., AUTO battery. so that it will come loose where it joins the tip and look messy. Oakland, California York: 370 Seventh Avenue Some receiving sets are provided with New Write for booklet illustrating and The Automatic jacks for the phones. In this case the phone the cords should end in a plug that will fit the describing Electrical Devices Co. hole where the jack is. Other sets have binding posts of a type adapted to hold a In this case a A NAVOX 116 THIRD STREET wire but not a phone tip. WEST connector and wires are used. Connectors adio Cincinnati, Ohio are sometimes sold as a part of the phone J equipment and sometimes they must be Me Power Amplifier Largest Manufacturers of ordered separately. If there are clips on may be phyoducer Vibrating Rectifiers in the World the ends of the phone cords they and yt' Sprenw able to get a hold on a binding post but cannot conveniently be applied to a jack. 1136 Science and Invention for March, 1923 "BUILD YOUR OWN" With "RASCO" PARTS! THE Radio Specialty Company -"RASCO- for short -now in its third year, is uuqu ouably the most unique radio parts supply house in the United States, if not in the whole world. This Company makes a specialty of very small orders. I'o order is too small to get immediate and prompt attention. The reason is simple: 80% of our orders are small. The reputation of this house was built upon service. Ask any of your radio acquaintances what they think of "RASCO" service, "RASCO" promptness. Thou- sands upon thousands of unsolicited testimonials are in our files, to prove that we serve the public as it has never been served in radio merchandise before. Be sure to get our great 68 -page catalog, containing over 500 different parts. Catalog contains over 300 illustrations. Order direct from this page. All goods sent prepaid in 24 hours. We pay all transportation charges. Money refunded if goods do not satisfy

RADIO FREQUENCY AUDIO FREQUENCY TRANSFORMERS "RASCO" BABY DETECTOR RHEOSTAT WINDINGS TRANSFORMERS Base is solid black compo- No better Transformer on These windings, with the switch the market. Highest class sition; mounted on same is The best Radio Frequency nickel holder and binding arm shown below, constitute a Transformer developed so materials. Impregnated complete rheostat for the experi- far. Designed for us by coils. Silicon steel stamp- post, which holds the fluted ings hard rubber knob with its menter. Resistance wound on Mr. R. E. Lacault, Asso- used. Save 50 per flexible black fibre. Carries 11/2 Editor of RADIO cent by assembling it sliding rod member. Pat- ciate ent nickel detector cup and binding post. Pat- amperes, resistance 6 ohms. NEWS. For wavelengths of yourself. R-4300, Rheostat Resistance 320 to 420 meters. Air R-1100, A.F. Trans- ent cup holds crystal. R-1898, Baby Detector, with Galena $ 50 20 core. Guaranteed to do former, ratio 41/2 to R-4301, Potentiometer Re- the work. This Trans- 1 $2.65 LUBRICATED sistance, each (200 shins) .35 former brings in the long R-1150, A.F. Trans- "RASCO" BLADE WITH COLLAR distances. former, ratio 61/2 to PANEL SWITCH Fits above. 1 patent spring fork holds R-2800 Radio Fre- 2.65 Our R-1675, each 10 quency Transformer. Oie switch handle always at $ size 174"x2'í" $2.00 HONEYCOMB COILS a uniform tension. At the same time it insures best No better coils on the market. contact New wip- MAGNET WIRE VACUUM TUBE Too well known for lengthy des- possible. SOCKET cription. Finn impregnation. ing contact covers every portion of the switch We list only best qualities. Made entirely of compo- Range given point. Double leaf blades used. "DCC" means Double Cotton is in meters when R-1921, "Rasco" Switch $ 40 Covered. sition. Gives no rise to varied with a .001 Variable Con- "GS" means Green rapacity effects, as metal denser: Silk. "E" stands for Enameled. sockets do. Positive con- PANEL SWITCH LEVER The following come on 8 -ounce tacts. No. Turns Range Price Imposible for this lever not spools: R-6500. Vacuum Tube R-5000 25 120- 250 $ .40 to make positive contact. Leg R-5001 35 175- 450 radius 11/2". Nickel -plated and socket $ 35 .45 R-2500, DCC 18 R-5002 50 240- 720 .50 polished. Lock fork holds the No. $ .50 - R2501, DCC No. 20 .60 CONNECTOR R-5003 75 390- 910 .55 screw w rotates) se ANTENNA R-5004 curely. Loose contact i(inmpossiblehichit R-2502, DCC No. 2" .75 100 500- 1450 .60 R-2503, DCC Made entirely of aluminum. R-5005 150 600- 2000 .65 R -200. Switch Lever $ 30 No. 21 .85 Will not rust. The four wires R-5006 200 R-2504, DCC No. 26 .95 900- 2500 .75 "RASCO" NAME PLATES R-2505, DCC No. 28 go to upper holes. Lower hole R-5007 250 1200- 3500 .80 The circular plate is our 1.15 takes lead-in. Don't solder R-5008 300 1500- 4500 new R-2506. DCC No. 30 1.65 .85 Binding Post Name The following come on 4-uttnce spools: your aerial. Dimensions, 2" R-5009 400 2000- 5000 1.00 Plate. Diameter, rya". These high. 1%" wide. R-5010 500 2800- R-2507, GS No. 20 $ .50 6100 1.15 denominations: PHONES, R-2508, GS No. 22 R-999, Antenna Connector 1.30 R-5011 600 4000-10000 1.30 GROUND, OUTPUT, .55 R-5012 750 5000-12000 - R-2509, GS No. 24 .60 1.45 "A" BATTERY -, "B" R-2510, GS No. 26 MOULDED R-5013 1000 7900-15000 1.70 BATTERY-, LOUD .65 DIALS R-5014 R-2511, GS No. 30 1.05 Highest grade made. Brilliant 1250 9750-19500 1.95 SPEAKER, GRID, LOAD. R-2512, R-5015 1100 14500-26500 2.20 "C"BATTERY-,AERIAL, GS No. 32 1.30 black composition. Figures R-2513 GS No. 36 1.85 inlaid in white enamel. For .4-, INPUT, "A" BAT - The CORD TIP JACKS BATTERY following come on 8 -ounce spools: '/." or 3/16" shaft. R-2514. E No. 20 $ R-3074, 21/2" 55 Take the place of binding posts -4 O CKLER o o .45 Dial, 1 on instruments or panel. Cord LO P, CONDENSER R-2515, E No. 22 .55 R-3075, Dial, 31/." 65 PLATE, "C" BATTERY R-2516, E No. 24 R-3076. 80 h tip firmly gripped by jack. Made -4-. FILAMENT. .60 Dial 3%" of brass, R-2517, E No. 26 .65 highly nickel -plated R-6000 to and polished. Screw to attach 6019, Binding CUßß¡yl R-2518, E No. 50 .70 FLUTED KNOBS lead wire. No soldering necessary. Post Name Plates, each i)Sfi R-2519, E Np: 32 8p denomination NNSS Made of best black composition, R-1500. Cord Tip Jack, each $ 15 $ 03 R-2520. F. 36 1.00 provided with 8/32" bushing. Dozen 30 LITZ WIRE Height 1", Diameter 11/.". CARDBOARD Square Name Plates R-323, equals No. 25 B&S, per TUBING Same denominations as above also these:SERIES R-2055 Fluted Knob $ 15 Only seamless foot $ 02 tubing made in 1st STEP, 2nd STEP, 3rd STEP, SECONDARY R-890, equals No. 28 B&S, per United States. Perfectly sea- CONDENSER, TELEPHONE, SECONDARY, foot 01 soned. Heavy wall. (I.D.-In- DETECTOR, TRANSMIT, GRID VARIO - R-891, equals No. 21 B&S, per "RASCO" POSTS ide Diameter. O.D.-Outside METER, PARALLEL, COUPLING, PRI- foot Diameter. L. -Length). 03 R-650, Post made entirely of MARY, LOADING COIL, RECEIVE, AN- R-892, equals No. 20 B&S per best black composition-8/32" TENNA, PLATE VARIOMTER, "BLANK", foot 04 R-6600, 3" I.D., 3'/e" O.D. z 7" L. $ 30 AUDION, ON, OFF. R-893, equals No. 11 B&S, per screw-each $ 08 R-6601, 31/2" I.D., 3%" O.D. z 7" L 35 R-834 to 866, Square Name Plates, each.'$ 04 foot 12 R-202, Post has nickel -plated R-6602, 31/2" I.D., 31/2" O.D. z 5" L 25 Dozen 40 Discomrts of 10 per cent in 100 -font lots. bottom part, each 08 R-6603, 3%." I.D., 4" O.D. x 5" L 27 R-839 'INCREASE CURRENT" (Right) Dozen, each style 90 R-6604, 4" I.D., 41/." O.D. z 5" L 35 INCREASE CURRENT" (Left) 650 R-6605. 2%" I.D. 3" O.D. z 2%" L 15 R Ea h 10 202 ...... RASCO SWITCH POINTS MICANITE TUBING VERNIER The 'Rasco" Catalog Nickel -plated and polished. The following have Especially suitable for CW work Cleverest vernier made. CONTAINS 75 VACUUM TUBE HOOK- been found the most popular. Can be used with any Nothing better made. Natural dial. UPS, 300 ILLUSTRATIONS I. 1/."x%", 6/32" thread, doz $ 35 color. Soft rubber ring engages 2, 3/16" high, 74" die., 6/32" R-250, Micanite Tubing, dial. Does away with 500 ARTICLES, 68 PAGES thread, doz. 36 4" dia., 6" long $1.20 vernier condenser. We All Armstrong 3, 3/16"x3/16", 4-36 thread, doz... 35 R -25I, Micanite Tubing, guarantee results. All metal parts moulded Circuits: These dia.. thick; shank 6/32" fn best black composition. Nothing to come , '/ 6" dia., 6" long 1.60 important circuits 4óz. 40 apart. Biggest hit of the season. a r e explained 5. 1/" dia., 3/16" thick; shank 4-36, doz. 40 JACKS AND PLUGS R-1450, Vernier $ 30 clearly, ail values 6, 3/16" dia., 3/16" thick; shank 4-36, doz. 40 having 7. die.. Best material. Only pure sil- "RASCO" been given 3/16" /" thick; shank 4-36, doz. 40 ver contacts used. Factory that leaving out noth- 75. Switch Stop %" long, 4-36 thread, com- CONDENSERS .e,al11M511l.2J ing With makes Postal Telegraph jacks makes these. that could plete nut, each 04 This is your guarantee. R-5050, Phone Condensers, each $ 20 puzzle you. 76, New style Switch Point. to be pressed R-5056, Grid Condensers, each 20 Jack. 4 -springs Just to name a into hakelite panels with forced fit. Wire R-5059. Grid Leak Condensers, each 30 few of is soldered to pin end. double circuit $ the Vac- Head 1" dia., R-1001, Jack, 3-springs .80 uum Tube cir- 1/16" thick, doz. 40 COPPER FOIL cuits: The 77, same es above, but head is 12" R-1002, Automatic 5 -spring Jack 1.00 V.T. dia. R-1003. Plug .65 Thinnest copper foil made, .001" as a detector and z 3/16" thick. doz. 40 thick. Comes 4" wide. one-step amplifi- BUS BAR WIRE SOCKETTES R-5025, Colter Foil, per ft. 5.10 e r ; Armstrong 10 -ft. length 80 circuits; one-step Substitute for Vacuum Tube Socket. This wire is square, measuring 1/16" by 1/16". radio frequency Four of these take one Vacuum Tube. RADIO CEMENT amplifier and Grasp firmly. Easy to solder as It is already tinned. Used de- tube Best contact Pos- on all up-to-date instruments. Sold in 2 -foot Weather resisting. Used particu- tector; three stage sible. Take less room. Are better. larly for cementing covered wires. audio - frequency lengths only. Coils R-1550, Sockettes, nickeled, set R.6400 Bus Bar Wire, per 2 -foot length..1.05 covered with this cement re- amplifier; short of 4 $25 quire no form. Wires hold together wave regenerative NON -INDUCTIVE solely with this cement. R-1551 Sockettes, nickeled, set RESISTANCE circuits; 4 -stage 73 Made of special graphite R-1750, Cement, 2 -oz. bottle 5.50 radio frequency of 4 (to take WD -11 Tube) 25 amplifiers; radio Note: Set of 4 sufficient to hold 1 Tube. copper -plated at the ends. Round rods 13ía" long. 54" diameter. Resis- TELEPHONE and audio fre- SHELL AND CAP quency amplifier; VACUUM TUBE FUSES tance accurate within 20 per cent. R-5300 Resistance 12,000 ohms $ 65 Per the experiment- inductively coupl- Insure your tubes against blow er we list this com- ed amplifier; Armstrong outs. R-5301, Resistance 70,000 ohms 65 superautodyne ;radio position shell and rap. No holes in shell what- frequency amplifier and crystal detector' com- R-2575, Fuse, 1 $ BRASS, RODS soever. Takes standard 212" diaphragm. bination V.T. detector Fuse, ampere15ampere one stage amplifier; R-2576, 11 15 R-2700, Shell -and -Cap, complete $ 65 two stage radio frequency amplifier and de- R-2577. Fuse, 2 ampere 15 R-8032, Brass Rod, R-2701, Shell only 40 tector with feedback coupling (regenerative); 8/32 thread, per regenerative UNIVERSAL BEARING ® length $ 08 MICA DIAPHRAGMS Armongsuergenaicr- THE bearing toholdvariometer - R-6032, Brass Rod, 6/32" thread, Per Made of special India mica in two cuit; two stage radio frequency and variocoupler rotors. Total length 06 sizes. diameter amplifier 21 and 1-13/10" .à coupled to a two -circuit tuner, using two - length of bearing Zak". Outside shaft, 11/2". R-1425, Brass Rod, plain %" round, per diameter. Excellent for experimentation in slide tuner regenerative receiver; Length of thread 1". Length of threaded sleeve, leth 10 two stage telephone work. audio -frequency amplifier, using crystal or R-3 616 Brass Rod, plain 3/16" round, R-2550, Diaphragm, 21/5" V.T.; one length $ 20 stage radio frequency detector, R-1375, Bearing $25 Per 06 R-2551, Diaphragm, 1-13/16" 15 two stages audio -frequency with feed-back coupling to first tube; power amplifier with This business was originated with the sole idea in mind to cater to the radio amateur who has small orders. ALL loud speaker; regenerative receiver and OF OUR ORDERS ARE SMALL. THAT IS WHY YOUR one stage amplifier for DX work; one stage SMALL ORDER CAN NEVER BE SIDE-TRACKED radio frequency BY US. A trial order will make you a life customer. Order from the above illustrations. 24 -hour service detector with feed-back guaranteed. coupling; three stages radio frequency, two "WE CAN ONLY DISAPPOINT YOU ONCE." Try us with a 50c. order and make us prove what we say. Prices stages audio -frequency loop reception; crys- inc ude delivery to your door. tal detector with rectification; one tube su- per -regenerative receiver; short wave regen- 100 Place, erative receiver with two variocouplers, ca- Park New York City pacity -coupled tuner; trap circuit to elim- DEALERS inate Interference; selective circuit to elim- Oldest and Original Exclusive [ inate interference The catalog contains Get Our Special 300 ilustrations. On account of Its great Radio Parts House in U. S. cost, it cannot be distributed free of charge. Proposition Mailed only upon receipt of Factories: Brooklyn, N. Y. - Elkridge, Md. 15 Cents in Stamps or Coin. 1137 Science and Invention for March, 1923

,,,,,,,,,,,,1,,,,,11111,,.. «.41111111 1111,,.111,,,,,11111,,,,,,1,,,1,1,11ae11,11,,,1,1111,,,,,,1,

_ Fish HangH anggi7p Young Ar® Ripenpen

= By DR. ERNEST BADE (Continued from page 1055)

placed in a ditch prepared for them. Here they remain for a few days and then they arc This radio game is just hung upon a plant by means of a thread as which consists of a viscid liquid. In this as much fun at our end for about five There's gen- position they must remain it is at yours. days. Then the parent picks them off, and, More Money For You uine satisfaction in knowing under their tutelage, they make their first that our radio parts and attempts in swimming. radio sets will "deliver the The reason for the suspension of the fish which are not, as yet, able to in RADIO goods" to some eager exper- young the fact that the young or unfailingly con- swim, is found in THE amazing expansion of Radio imenter, will receive plenty of clean, oxygenated vey a message of interna - surface, where they can has opened up thousands of won water near the on land and to the ear of a the contents of the food still remain- derful new positions tional importance absorb sea. Big salaries, fascinating easy ing in the egg sack. Only after this has waiting world. are they enabled to swim. work, short hours, and a wonderful been devoured ambitious men At the SIGNAL plant we never Then, under the care of the parents, they future are offered to forget that if we scrimp on material hunt the tiny water infusorians, nature's who get into Radio now. someone baby -fish food. Without suspension, the Take advantage of these wonderful or slight our work, then soon be into a big paying and per- young, delicate creatures would opportunities to step will surely be disappointed, buried deeply under the dust -like muck position in this great new field. Radio haps a despairing call for help may which rises in dense clouds at the least offers you an opportunity to travel and be made in vain. agitation. This would then fill the respira- see the world, with all expenses paid, tory organs and the creatures would suf- and a fine salary besides. Or you can is joy to perform each So it our f ocate. stay at home and work up to a position little or big, with the ut- paying up to $10,000 a year. One of operation, Young fish with well ossified skeletons, most of conscientious precision, are often pro- our recent graduates secured a position the bony fish (Teleostei), paying a no life can ever adhesive cement organ situ- one week after graduating knowing, thus, that vided with an salary of $300.00 per month. defective SIG- ated just above the mouth. With its aid, be charged against attach them- apparatus. the young, just -hatched fish, NAL selves to the surface of the waterplants, etc., Easy to Learn Radio equipment bearing the where they then remain until the egg sack name of SIGNAL may safely be has vanished. The larval stages of Protop- Radio at Home honest terus, Lepidosiren, etc., belonging to the depended upon for good, -fish (Dipnoi), still possess Hundreds of men are already earning hand- sub -class lung some incomes in this wonder science. If you service. outer gills and these are all provided with want to get into a profession where oppor- such cement organs and in this respect they tunities are unlimited make Radio your career c:osely resemble the tadpoles. This, undoubt- -become a Certified Radio-trician. to the relation existing to these Thousands of Certified Radio-tricians are r edly, refers wanted to design Radio sets, to make new two groups of animals. Radio improvements; to manufacture Radio to install it; to maintain and Factory and General Offices: electric fish of the group Mor- equipment and 1911 Broadway, Even the operate great broadcasting stations and home MENOMINEE, MICH. myridae, peculiar individuals inhabiting the Radio sets; to repair and sell Radio appa- fresh waters of Africa, are exceptionally ratus; to go into business for themselves; to Atlanta New York Boston and are pro- operate aboard ship and at land stations. Pittsburgh Chicago San Francisco characteristic of this region You can easily and quickly qualify in your Cleveland Minneapolis St. Louis vided with adhesive organs in their early spare time at home through the help of the Montreal Toronto stages. National Radio Institute. Prominent Radio experts will help you. Four wonderful in- in struments are furnished free, making the You'll find our local address your work thoroughly practical. The same plan Telephone Directory that has already helped hundreds of our grad- (2101) The Sleep uates to real success and real money in Radio is open to you. INFORMATION COUPON nator page 1114) Big Book Free Signal Electric Mfg. Co., (Continued from 1911 Broadway, No other field today offers such great oppor- Menominee, Mich. tunities as Radio. Cake your choice of the many wonderful openings everywhere. Pre- Please send catalog and bulletins giving simply moves a switch at his right, which pare now to step into the most interesting complete information about SIGNAL Radio disconnects the electrifying current. It is and best paid profession today. Read about equipment to name and address written in the tele- the opportunities open now-the different margin. the same when he wishes to use kinds of work-the salaries paid. Write today phone. If he did not turn off the switch he for the free 44 -page book that tells how probably would get a somewhat severe shock. America's first and biggest Radio school can desk to his make you a Certified Radio-trician in your He can, however, work at his spare time. heart's content, because the desk itself is supported by glass insulators, so it makes National Radio Institute -a', no difference if the desk is metal or wood. 1345 PENNSYLVANIA AVE., N. W. KEEP - In this illustration we also see an addition 14-C Washington, D. C. A DAY AHEAD in the form of ozone generators. This is Dept. because it has been of the headlines of tomor- another suggestion, row's newspapers! found that ozone is one of the most stimulat- Radio Institute, Dept. 14-C Don't be satisfied with the National (is regular broadcasted programs! ing and exhilarating agents known, and if 1345 Pennsylvania Ave., N. W. Get the moat out of radio! used in the right proportions will also greatly Washington, D. C. Hundreds of radio enthusi- from even think- asts are doing it! i0 help to keep the workers Send me your free book, "How to Learn tube set w ith a ing about sleep. Radio at Home," which tells all about the Equip your vacuum opportunities in Radio, how spare time study With methods such as these, if translated at home will qualify me quickly as a Certi- FINCH RADIO REL fied Radio-trician so I can get one of these into practice, there is no probability that the free Employ- and you will automatically receive anti atA theY splendid positions, and how your same time have a permanent record of a 11 the subjects will experience any ill effects, and ment Service helps me to secure the job important and interesting news events o f the not be worse off for having worked a I want. world, whether or not you know the code. will week, or even a month, day in and day out. Age Send Today for Booklet S103 \ Name Of course, any time during the day clothes Street and linen can be changed, and a shower taken, to refresh the body, just the same City State FINCH RADIO M'FG,CO. Z93FIFTt1 AVE.N.Y.CITY. as we, take it now. Science and Invention for March, 1923

I .374 Opportunity Ad -lets many remarkable YOU will find opportunities and real bargains in these columns. It will pay you to read and investigate the offerings made every month by reliable firms, dealers and amateurs from all over the country. No matter what you may be seeking, whether supplies, automobile accessories, the opportunity to make money, or anything else, you will find listed here the specials of the month. best and most attractive Advertisements in this section twelve cents a word for each insertion. Name and address must be included at the above rate. Cash should accompany all classified advertisements unless placed by an accredited advertising agency. No advertisement accepted. for less than 10 words per 6 Ten cent. discount for issues, 20 per cent. discount for 12 issues. Objectionable or misleading advertisements not accepted. Advertisements for the May issue must reach us not later than March 15. The Circulation of Science and Invention is over 160,000 and climbing every month EXPERIMENTER i PUBLISHING CO., INC., 53 Park Place, New York City, N. Y.

Advertising Service Agents Wanted (Continued) American -Made Toys For Earn big money fast applying gold quick results use direct mail advertising. Lettere, initials to autos. Manufacture metal Indians. Casting form $2.00. H. folders, campaigns. Free suggestions. Wilson, 247 Wil- Every owner buys-$ 1.35 profit on $1.50 sale-particulars Langford. 1020 Oliver St., Baltimore, bid. liam St., East Orange, N. J. and samples free. Write quick. Lithogram Co., Dept. ,,,,newm11mu11u,11,w,11wnnnu1111u,.,,,111111.1unuw,wwnnun.w11wwa..mMwe.r1.1..» 19. East Orange, N. J. Manufacturers on large scale, also homeworkers, wanted to manufacture Metal Toys and Novelties. Millions needed Only one sale a day means $200 per month! Five of Barking Dogs, sales, $1,000 month! Marvelous Wag -Tail Pups, Wild Animals, Automa Aeronautics per new adding machine. biles, Indians, Cow -Boys, Baseball Players, Cannons, Toy Retails 815. Work equals $350 machine. Adds, sub- Soldiers, tracts, multiplies, divides Crowing Roosters, Statues of Liberty, Miniature automatically. Speedy, accu- castings of Capital, Bathing Girl Souvenirs and others. Boys build three foot model aeroplane at small cost. rate, durable, handsome. Five-year guarantee. Offices, Unlimited possibilities. Write Aero Shop, 3050 Burlbut Ave.. stores, factories, garages, Guaranteed Casting forms fur- Detroit, Mich. buy one to dozen. A fortune nished manufacturers at cost price from up, with 11111111111111111111111111111111,1111 for live agents. $5.00 14.1b Write quirk for protected territory and complete outfit. No experience or tools free trial offer. Lightning Calculator Co., Dept. W., Grand necessary. Thou- Rapids, Mich. sands made complete per hour. We buy goods all year and Agents Wanted pay high prices fnr finished goods. Cash on Delivery. Free. Formula Catalog. Laboratories, Boylston Bldg., Contract orders placed with manufacturers. Catalog and Chicago. information free. Correspondence invited only if you Agents-Steady Income. Large manufacturer of soaps, mean business. perfumes. toilet articles and pure food products, etc., Large Shirt Manufacturer wants Agents to sell complete Metal Cast Products Co.. 1696 Boston Rd., wishes representatives in each locality. Manufacturer line of shirts direct to wearer. Exclusive patterns. Big New direct to consumer. values. Free samples. York.ro Big profits. Honest goods. Whole Madison Mills, 503 Broadway, or spare time. Cash or credit. Send at once for particu- New York. Automobiles-Automobile Supplies lars. American Products Co.. 8479 American Bldg., Cin- Agents. to $200 cinnati, Ohio. $60 a Week, Free Samples. Gold Sign Letters for Store and Office windows. Anyone Automobile owners, garagemen, do lt. an mechanics, send today Big Big demand. Liberal offer to general agents. for free copy America's most magazine. money and fast sales. Every owner buys gold Metallic Letter Co., popular motor Initials for his auto. You charge $1.50; make $1.35. Ten 432Z N. Clark St.. Chicago. Contains helpful articles on overhauling, repairing, igni- orders daily easy. Write for particulars and free samples. Agents-Just like selling gold dollars at 69c each. tion, carburetors, batteries, ete. Automobile Digest, 541 American Monogram Co.. Dept. 71. East Orange. N. J. That's what J. A. Saunders, of Pawtucket, says Butler Bldg., Cincinnati. our wonderful about pure all virgin wool made-to-order suits, Blue Prints. Automobile Armature connecting dia- Fords run 34 miles on gallon gasoline. Other cara retailing at $29.50-none higher. Finest grams show proportionate selection of fab- 1922 Edition. Charles Chittenden, B3024 Matthews, saving. Wonderful new carburetor. rirs--serges, worsteds, cassimeres and flannels of superb Kansas City, Mo. Starts easy in coldest weather. Fits any car. Attach quality. Fit.. style and quality unexcelled. Satisfaction yourself. Money back guarantee. Sent on 30 days' trial. guaranteed. This is a line that will bring repeat busi- Agents wanted. Air Friction Carburetor Co., Dept. 3226, ness and big money. A big Dayton, opportunity for hustlers. No Books Ohio. experience needed. We will teach you. Write today state territory desired. J. B. Simpson, Inc., Dept. 499, Use Insyde Tyres in your old casings and get from 3 831 W. Adams St., Chicago. Perpetual Motion, by Percy Veranee. A history of the t.e 5 thousand miles more service. Positively prevent efforts to discover same from earliest days to the present. punctures and blowouts. Used over and over again. Low Agents-Big returns, fast office seller; particulars and together with a scientific discussion regarding the possi- priced. Big money saver. Agents wanted. Write for samples free. One Dip Pen Co., 12 Daily Record Bldg., bility of its ultimate achievement. Profusely illustrated, terms. American Accessories Co.. B-784, Cincinnati, Baltimore, Md. 357 pages. Price postpaid. $2.00. The Enlightenment Ohio. Specialty Co.. 305 Fourth St., Edwardsville, Ill. Automobile Free to Tailoring Agents: Make $75 a 300 per cent. Profit: Selling Kleanrite week and up and get an automobile free taking orders Books for Sale on Occultism-Sisaticism-Theosophy- Magic Clothes our fine for Mental Science-Advanced Washing Compound. Sells. 25e; Profit, 18e. Sample free. tailored -to -measure suits. Big assortment of All - Thot-Sex Secrets-Seerahip Besteyer Products Co.. 1941-W Irving Park, Chicago. Wool Fabrics at the one low price of $29.75. Also won- -Clairvoyance-Crystal Gazing-Numerology-Astrology- derful showing of Summer -weight fabrics at $17.50. Yogi-Hermetic and Rosicrucian Philosophy-List Free. Make $25 to $50 week representing Clown' Every order pays you big cash The Grail Press-Desk B, 712 G St., N. E., Washington. Famous profit in advance. We D. Philadelphia Hosiery. direct from mill-for men, women, supply finest selling outfit and give automobile free C. children. Every every man who to pair guaranteed. Prices that win. Free qualifies. Write quick for startling offer. Books. hook How to Start" tells the story. George Cloves Com- Dept. 556, Park Tailoring Company, Chicago. Literature Instructive. Lists. Higene's, pany. Desk 27, Philadelphia, Pa. 52411 Post. Street. San Francisco. Radio Agents-wanted in every, town to sell Ames Radio Capable Men May Earn 15 Products. We Sexologieal Literature, the most extensive. Catalogue $ to $25 day selling high manufacture long distance Radio receiving sent on grade Double Wear Shoes direct from factory sets and parts. Big profits. request from the Original Book League, S. I. 5 to wearer. Write for plan. Picard Columbus Circle, New York. Big opportunity for you. Clever Selling Plan insures your Radio Corp., Dept. MC, 18 Wrest 46th St., New York. success. Write today for full particulars, style sheets, etc. Doublewear Shoe Co., Manufacturers, 10A, Minneapolis, Free Book. Start little bfall Order business anywhere. Gleanings of a Mystic. By Max Heindel. New infor- Minn. Home employment evenings. Beginner's Working Outfit mation regarding Initiation. What It Is and Is Not, and furnished. Instructive Bonk free. Pier, Dept. 155-A, many other fine points never before presented in this Big money made silvering mirrors, plating and refin- 71 Cortland St., N. Y. form. 200 pages. Cloth bound, $2.00 post free. Ready ishing metalware. autos, chandeliers, headlights. about Den. 15th. Rosfcrucian Fellowship. furnished. Outfits remendous Opportunity Box 17, Ocean- N. Dacie Laboratories, 1133 Broadway, New for agents, in - side, Cal. York. dispensable, rapid Speedy Dish The $3.50. No competition. ser. Price No investment. Easy selling Diseases and Their Innate Healer. Book 50 Ambitious - Men, write today for attractive proposition. plan. Convenient sample. Commission cents. selling plication daily. Make ap- Arthur Stevens, Wauseon, Ohio. subscriptions to America's most popular automobile today-exclusive territory. Shepperd-Luth Mfg. and sportsman's magazines. Quick Co., 16K Hudson St., New York. Hypnotism-Astounds, Pleasant Sales. Big profits. Controle others, 25 easy lessons. work. Digest Pub. Co., 9541 Butler Bldg.. $1; ' 1lindreading (any distance), Cincinnati. Live Agents make $10 Day 30e. Science Instl- Splash selling Eureka Strainer and tute, SE1014 Belmont, Chicago. preventer for every water faucet. Takes on sight. Agents Wanted in Every City to sell standard Widely advertised and known. Get How to Make Wireless apparatus Radio Seed details today. A. J. Receiving Apparatus. 100 pages on a liberal commission basis. A few stocking Filter Co., 73 Franklin, New York. -90 illustrations. Only strictly modern radio apparatus agencies open to reliable parties. Delfelro, 12 Meeting are described in this book and the illustrations St Pawtucket, R. I. Build Your Own Business-Renewing scriptions and de- and carpets and dyeing rugs are so clear nad simple that no trouble will be on floors of offices, hotels, homes. New experienced in making the instruments. 27,000 Records guaranteed with one Everplay phono- method. Big profits. $10.00 Day 35r postpaid. Paper covered, graph needle, information. easy. Write for full Experimenter Publishing Co., Book Dept. new, different; cannot injure records; Texply Company, I6 -A, Somerville, N. J. 53 Park Place, New York City. $10.00 daily easy. Free sample to workers. Everplay, Desk 37, SleClurge Bldg., Chicago. 57 miles per gallon made with 'Vaporizer. new patented gasoline How to Make Wireless Sending Apparatus. 100 pagea- Write for particulars. Vaporizer Co., Puk- 88 illustrations. Written and We wish representatives in every community wana. S. Dok. published entirely for the to secure wireless enthusiast who wants to make his own radio subscriptions for Science and Invention, Radie News, and apparatus. Contains Practical Electrla. This is a wonderful Rubber more information on "how to make opportunity for tubes; Raping for tires and it" htan any other book we know of. Paper bound. Amateur Radio Enthusiasts to make big money quickly. superrsedesEevlulcanizationu over 35c Write Experimenter per cent; put it on 800 postpaid. Experimenter Publishing Co., Book Dept., Publishing Co., Inc., 53 Park Pl., cold. It vulcanizes itself in two min - 53 Park Place. New York City. New York City. guaranteed to t life of the tube; sells to ire or ery u owne r ande accessory dealer. For The How and Why of Radio Apparatus, Agents. Big Profits. Selling Wunrub Polish, for particulars how to make big money by H. W. Serer. niture, Woodwork. Fur- Amazon and free sample. address E. E. This newest book on radio matters fulfills a dis- Automobiles, etc. Cleans and Polishes. Rubber Co., Dept. 601, Philadelphia, Pa. tinct in Write for B1g Offer. «nu,11,.aw,1,,,,111111111,,,,11,,,,,,,, gap wireless literature in that, while the treat- Free Fritch's Laboratories, 312-D, 1.1.1111,11,11111,111,111,,, .1.í11111111111n. North Carpenter, Chicago. ment is made as understandable and as free from mathe- mathirs as possible, it at the same time incorporates a Correspondence Courses wealth of technique 10 mirrors, ating and and Instruction for the Radio Ama- lampa, reflectors, autos, beds, refinishing teur-the Radio Operator-the Installation and Designing delierss by new Dollars Saved. Expert-as well as Outfits furnished. Write Gunmetal Co., Ave. D, Decatur, Used correspondence courses of all kinds teachers and students of the subject sold, rented and exchanged. List free. (Courses bought.) in general. A very broad field has been covered by Lee Mountain. Pisgah, Alabama. the author, at the same time giving a great deal of Information Housewives Buy Harper's Invention en sight. New busi- not found in other text books. If you are ness. No Competition. Ten -Use Set engaged in any branch of the Radio or allied arta at all indispensable is combination of ten you will surely household necessities. $7.50 to $30.00 a Duplicating Devices need this latest contribution to radio day easily. Write for Free trial offer. Harper literature, which is destined to be found on every radio Works, 112 A Brush man's book shelf before long. A at the following Street, Fairfield, Iowa. "Modern Duplicators save Time, glance Gets Labor and Money. list of chapters gives but a very scant idea of the Agents. Our soap Business. Reproduces Typewritten or penned extensive and useful and toilet article plan is a wonder; Drawings, Lessons, Music. letters, radio knowledge provided in its get our free sample case offer. Ho -Ro -Co., Menus, Bids, Notices, Speci- text: The Induction Coil; The Alternating Current St. 138 Locust, fications. Maps or anything in one or more Transformer; Louts. two per colors. Prints Radio Transmitting Condensers; The Spark minute. Special Sale On. 30 Days' Free Trial. Gaps; Radio -Transmitting Inductances; Radio Receiving Write and learn how to start $2.25 up. Booklet Free. B. J. Durkin -Reeves Tuners; Radio Receiving capital profitable business without Pittsburgh, Pa. Ce., Condensers; Detectors; Tele- or experience. Slivering mirrors, refinishing auto phone Receivers; Radio Amplifiers; Construction of a headlights, tableware. ,,,,,,,,,,,,,,,,, rrrrr rrrtr rrrrr trreerwrrerunnommurnurrrItrurrrrtrtrrgurrtrurrgurrIgratigttrIllitc11111111,11111{111.111 Direct Reading Wavemeter national plating. Outfit furnished. Inter- and Decremeter; Antenna Con- Laboratories, Dept. 25, 309 Fifth Ave., New struction' The Calculation and Measurement of Induc- York. Electrical Supplies and Appliances tances; Appendix containing very useful tables, covering Sell Wall Emblems. all subjects treated in this very unusual book. This Every Lodge Member wants one. Blueprints. newest of Radio Works, Big money-all or spare time. Free sample Diagrams of Electrical Connections for cloth bound in Vellum de Luxe. bonus plan. and cash nearly every purpose. Authoritative Gold stamped and Hand Sewed, has 160 pages. Size Kier Emblem Co., Dept. S.I.3, 538 So. works. Particulars of book, Clark. Chicago, free. Samples 20e. Charles Chittenden, A3024 Matthew'', 6x9 inches. The How and Why of Radio Appa- Kansas City, Mo. ratus. Postpaid, $1.75. Experimenter Publishing Ca., hook Dept., 53 Park Place. New York City. 1139 Science and Invention for March, 1923 Miscellaneous Business Opportunities ForMen for butterflies, 5 lbs., $1.25: 10 Ibs., Get posted for Spring --Good prices paid Dignified, exclusive. Homespun Tobacco-Chewing, display advertisement. page 1121. Become a Landscape Architect. 20 lbs., $4.50. Smoking, 5 lbs.. $1.25 10 inserts. See Sinclair fino money -making opportuni- 9 2.50; you uncrowded profession offering t 20 lbs., $3.50. Farmers Union, Mayfield, So -Brite Radium luminous pendant Free. Helps incomes common. Easy to master ts., $2.00; two -cent ties. $5,000 yearly F locate electric light switch in the dark. Send course. Established 1916. Get entuuckylllllll,Lll,,,,ll,l,,,,llll,,,, 1,ll,,,,,,,,,,,,,rtnorrurnme,,,,elemeleu,,,ue, through our correspondence 66-M, stamp for details. Radium Application Co., 44 Paterson information today. American Landscape School, ' Street, Jersey City, N. J. Newark, N. Y. Formulas Fenner., and sell soap, Joker's novelties. Great fun. List free. D. Here's a money -getter! Manufacture 2401 Jefferson, Louisville. Ky. everybody ntly Moneymaking Books, flans, Formulas. Catalog Free. somethingfrequndfor making high-grade Chicago. w six formulas I deal Book Shop, 5501-E, North Robey, harder you twist the tighter it Box 266,el Lynn, Mass. Polly Wrench-The Write us today. snap. Free-Formula Catalog. Laboratories, Boylston Bldg.. grips; WCs guaranteed. Three sizes -75e, $1, $1.50, will furnish formulas and trade secrets. money order or draft. Gloss Polish Co., General Deliv- Chemical Expert 238 ( hicago. All lines. Lists free. W. L. Cummings, Pb. D., ery, Peoria, Ill. secrets. Over Gordon Ave., Syracuse, N. Y. 3,500 Money -Making Formulas and trade Round -up and Convention-get wise. Round- field. Catalogue free. Englewood Book Shop, Inventors' Start a cleaning, pressing, dyeing shop. Splendid 1 00 pages, $1.00. up. Cincinnati, O. C/o Billboard. Big profits. Booklet free. International System, Dept. 7 021-B, South Winchester, Chicago., Excelsior Springs, Mo. Blue Prints, Castings, 1% /-Horse power gasoline 21. horizontal or vertical. Box engines. Model steam engines, Make money with your camera. P. Lancaster. For the Photographer Blue Prints of any one, 50 rents. Order from ad. 967, Los Angeles. Stamp for circular. Master Model Co., Box 212C, idea or inven- Have You a Camera? Write for free sample of our big Ill. Will pay cash for sole right to novelty pictures and earn Elgin, 10 cents. Address Lock Box 66, , nagazino, showing how to make better Ask for Free Vocational tion that retails for Photography, 465 Camera House, Bos- Choose the Right Vocation. Station F, New York City. t noney. American Self Analysis Chart SI. Vocational Service Bureau, 29 on Mass. dope. I Chicago. Dollars yearly in your Backyard. No mushroom nl71lu E. Jackson, Particulars free. Metz. 313 E. 89th St.., New York. Join National Institute Inventors. 8 E. 14th St.. New Games and Entertainment Motorcycles-Bicycles York City, strong protective membership society. Will market patents. Dues, $10. Plays, Stage secure, develop, manufacture, Tricks, Puzzles, Jokes, Magical Apparatus. wants. and Sensational Escapes. Used parts for all motorcycles cheap. State Booklet free. Supplies, Mind -Reading, Acts Cycle Co., 1922 Westlake. Seattle, Wash. newspapers. Lists free. for 160 -page illustrated 1922 professional cata- Schuck Advertise. Country town Send 10e Wis. Pennell Company, Covington. Kentucky. logue. Oaks Magical Co., Dept. 549. Oshkosh, Bontt buy a Bicycle Motor Attachment until you get our Wonderful catalogue and prices. Shaw Mfg. Co., Dept. 6, Gales- We start you in a business of your own. burg, Kansas. opportunity to make money. Make and sell your own Health Booklet explaining our system free. Rogers products. Street, Dayton, Ohio. ..onsulting Laboratories. 15 Liberty Free to Men-Information of a scientific nature that has Musical and operate nought physical vigor and happiness to thousands. No Get Into Business for Yourself! Establish for reply. Dr. C. I. Specialty Candy Factory" in your com- barge; no obligation. Enclose stamp Song Poems Fitted to music by recognised songwriter. "New System oppor- Vood, 551 East 47th Street, Chicago. t.munity. We furnish everything. Money -making Sharks exposed. J. Doane, 2128 Alice Place, Chicago. free. n u n n u n n,,,,, u,, ,,,I ,,, ul,, u,,, n u 1,,,, 1,,,,,,, u n n n, u u u u u n,,,,, tunity unlimited. Either or womOrange,en.Booklet or no $1.00 if cured. ,,,,,,,,,,,,,, u,,,, n,,,,,,,,, un,,,,, .1. Tobacco or Snuff Habit Cured pay; Ragsdale Co., Drawer 129, Eastn Remedy sent on trial. Superba Co., S. A.. Baltimore, Md. lllll Old Money Wanted Enter a New Business. Earn $3,000 to 96.500 yearly and fitting a foot specialty; in professional fees making to; Wanted $2 to $500 Each paid for hundreds of old or odd coins. openings everywhere with all the trade you can attend Help home in a few weeks at Keep all old money. You may have very valuable coins. easily learned by any one at Send 10 cents for New Illustrated Coin Value Book. 4x6. expense; no further capital required; no goods to Detectives Earn Big Money, Excellent opportunity. small Address Stephenson Experience unneces- We pay Cash. Get posted. Clarke Coin Company, Ave. buy; job hunting, soliciting or agency. Travel. Great demand everywhere. 15. LeRoy, N. Y. Laboratory, 18 Back Bay, Boston, Mass. sary. Particulars free. Write, American Detective System, York. Prepare-Sell. Your Own Products. Formulas, trade 196$ Broadway, New secrets. Different, dependable. Catalog free. D. Thaxly Patent Attorneys Gov't Railway Mail Clerks start $133 month: expenses Co., Washington, D. C. free. Columbus In- Universal Bu- paid. Specimen 53 Great Money -Making Plans Free. H Co ex tnin taon questions Inventors: Protect your invention through A. M. Wilson. reau-K, Boston, Mass. Inc., Washington, D. C. Over 25 years of efficient, $3 to $10 a day; spare time expert, confidential service. Skilled in Radio -Electrical. Easily learned, im- Be a Mirror Expert. Mechanical fields. Our new illustrated Silvering Mirrors, French plate. home at first: no capital; we train, start you making and Chemical and profits. Plans free. Wear Mirror Works, Dept. 27, Free prospectus. W. R. booklet, giving much necessary and very useful informa- mense silvering mirrors French method. will Excelsior Springs,, Mo. 26 McKinley St.. Baldwin, N. Y. tion which every Inventor should know, be sent mummu,rrrr 11.1,1111,1,,,,11.1,11111M.MMM.,,,,,,,MM.uu. Derr. Pres., free upon request. Prompt and careful attention. Highest Firemen, Brakemen, Baggagemen. Sleeping ear train references. Moderate fees. Send sketch or model for our Chemistry porters (colored). $140-200. Experience unnecessary- 897 careful opinion and preliminary advice. Write today to Railway Bureau, East St. Louis, Ill. A. M. Wilson, Inc. (Radio 3 ARH), 312 Victor Bldg, Chemical Laboratory. 100 D. C. (Successor to business established How to Make and Use Small month. Men, Washington, pages, fully illustrated. Construction of laboratory furni- Become Railway Mail Clerks. $133-$195 in 1891 by A. M. Wilson.) chemical balance and other appa- 18 to 35. Common education sufficient. Sample exam- ture, electric furnace, Franklin now ratus; inorganic chemistry, novel experiments, glass blow- ination questions free. Write immediately. Millions spent annually for ideas! Hundreds explained, 75e prepaid. Illustrated catalog Institute Dept. N25. Rochester, N. Y. wanted! Patent yours and profit! Write today for free ing, etc., fully how to protect how to invent, ideas of laboratory supplies and scientific books sent free. D. books-tell yourself, East 110th Street, New York, Men and Women. Nation-wide wanted, how we help you sell, etc. 212 Patent Dept.. Altman Company, 225 Hotels Need Trained American Industries, Inc.. Washington, D. C. March issues 20e. Year demand for high -salaried men and women. Past experi- Chemical Science, January We you by mail and put you in .1. ence unnecessary. train Inventors. Send sketch or model of invention for 50e. Swedesboro, N. with big opportunities. Big pay, line living, inter- Dr. T. O'Conor Sloane, touch for opinion eoncerning patentable nature and exact cost of Learn Chemistry at Home. esting wort[, quick advancement, permanent. Write "How to Obtain a Patent, sent free. educator and scientific authority, will teach you. Big Lewis Hotel patent. Book, noted to take a Free Book, "Your Opportunity. Tells what every inventor should know. Established Our home study correspondence course fits you Training Schools, Suite 3442, Washington, D. C. Highest references, prompt service, position as chemist. See our full -page ad on page 1045 twenty-eight years. of New York, 140 Liberty reasonable charges. Chandlee & Chandlee, 441 Seventh. of this issue. Chemical Institute Make money in spare time mailing letters. Men, write Washington. D. C. St., New York City. now, enclosing stamped addressed reply envelope. Nor - Your chemical problem solved and working process fur- mantle R Dept., 147 W. 23d St., New York. Patents. Send for free booklet. Highest references. me. W. Stedman Rich- results. Promptness assured. Send model or draw- nished for Five Dollars. Write writing for newspapers. Best ards, Consulting Chemist, Box 2402, Boston, Mass. Earn $25 Weekly, spare time, ing for examination and opinion. Watson E. Coleman, magazines. Experience unnecessary; details free. Press Patent Attorney, 624 F Street, Washington, D. C. Experimental Chemistry. Book of over 'One Hundred Syndicate, 5665 St. Louis, Mo. Experiments, many new and original. 50c cash. for butterflies, Patents-Prompt, personal efficient service by an at- Chemical Get posted for Spring-Good prices paid of Patent Practice. Oliver Steller. Oshawa, Ontario. Canada. See Sinclair display advertisement, page 1121. torney -at -law, skilled in all branches inserts. Over 18 years actual experience; full information upon re- quest. B. P. Fishburne, 330 McGill Bldg., Washington. Exchange Insects Wanted D. C. Eddie butterflies, Inventors write me about patents. My fees payable Used parts for C36 Buick. Write your needs. Get posted for Spring-Good prices paid for monthly. Booklet free. Frank Fuller, Washington, D. C. Viroqua, %Vis insects. See Sinclair display advertisement, page 1121 Hirschfield, ,,,,u,nunnn ,ua ,n,,,,, ,,,n,n, ,,,,,,,,, Patents Secured. Prompt service. Avoid dangerous delays. Send for our "Record of Invention" form and Farms, Lands, Etc. Instruction Free Book telling How to obtain a Patent. Send sketch or model for examination. Preliminary advice without for your real estate, busi- at Home. Dr. T. O'Cmior Sloan, charge. Highest References. Write Today. J. L. Jack- Property Owners-Get cash Learn Chemistry Bldg., Washington. D. C. ness, invention or other property. To quicklysell, ex- noted educator and scientific authority, will teach you. son & Co., 118 Ouray buy property, any kind, anywhere, write Our home study correspondence course fits you to take a Ex- changeor on page 1045 Herbert Jenner, Patent Attorney and Mechanical Security Co.,e Hannibal, Position as chemist. See our full page ad D. C. I report if patent ,,,,,,,MIMI.,,,,,,.111.1.,,,,n,,,,,,. New York, 140 pert, 624 F Street. Washington, , ,102. Mo. of this issue. Chemical Institute of and exact coat. Send for circular. Liberty St., New York City. obtainable for "Record of Invention" For Inventors Courses only one -quarter original Protect your rights- Write Used Correspondence and booklet about Patents. Prompt personal service. Ad- price. Free bargain price list. 1,000 courses. Courses V Columbian Inventors-Expert professional service at lowest cost. 45 W. 42d St., New York. vice without charge. J. Reaney Kelly, 612 Amon 2240 bought. Students Exchange, D. C. Write for explanatory literature. -Baxter, n11nn,,,u,nm,,,,n11111,11,0,1 ,,,1.111111111,,,e,,,,,,nn1n,wnn,,,..,,.m,,,,,,n,mnn,,,n Building. Washington, York. .11111114.1111111L1r Byer Avenue, New Inventors-Send for form "Evidence of Conception" Get Your Own Patent, $40 complete. Application Languages to be signed and witnessed. Form, fee schedule, informa- blanks and full instructions $1. Theodore A. Cutting, tion free. Lancaster & Allwine, 242 Ouray Building, Campbell, Cal. World- Romic System, Masterkey to All Languages. Washington, D. C. Primers. 23 languages, $1.94 each language: Arabic. 900 Mechanical Movements. 50 Chindau, Danish, Dutch, Monroe Miller, Ouray Building. Washington, D. C.. Inventor's Educator. Bohemian, yBulgarian, Cantonese, expert. Best Perpetual Motions. How to procure and sell patents. English, Scotch English, French, German, Hungarian, patent attorney. mechanical and electrical Mechanical Movements greatly assist inventors, suggest Italian, Japanese, Latin, Panjahi, Polish, Portuguese, quality of work and results. Moderate charges. how to select an attorney and avoid Swedish. Pronun- new ideas. Explains Rumanian, Russian, Sechuana, Spanish, sketch for search of pertinent U. S. Price $1.50. Fred G. 94 languages, 30e each language. Lan- Patents! Send D C. ciation-Tables, patents and Report, including copies of patents nearest De terieh, 601 Ouray Bldg., Washington,free. guages Publishing Company, 8 West 40th Street. New valuable suggestions help your idea. Earlier patents may offer Unpatented ideas can he sold- I tell you how and York. for improving or perfecting your invention. Preliminary SW malte the sale. Particulars free. Write W. B. information or advice without charge. O'Connell & Greene, 106 The Atlantic, Washington, D. C. Machinery and Tools O'Connell, 900 Seventh Street, N. W., Washington, D. C. Inventors-Sell patent manufacturers articles similar invention. Guaranteed addresses 5c each, minimum Patents Procured. Trade -Marks Registered. A com- Ann Arbor, Concrete Building Block Machines and Molds. Catalogue experienced, prompt service for the protection (money order), 50c. General Information, Third St., SL prehensive, Mich. free. Concrete Machine Co., 305 South and development of your ideas. Preliminary advice Louis. gladly furnished without charge. Booklet of information "Inventors' Guide free on request; gives valuable idea free on request. Richard inventors. Write Frank and form for disclosing advice and information for all B. Owen. 130 Owen Building, Washington. D. C., or Lederman, Registered Patent Attorney. 15-E Park Row, Mail Order Business 2278-T Woolworth Bldg.. Now York. New York. it. Mail Order business: us for our book, "How to Obtain application for patent, it will $50 week evenings-I made Inventors should write Before or after filing your for stamp tells how. Sample and plan, 25c. a Patent," which clearly sets forth what may be patented to read over my 'Inventors Advisor No. 4." Free booklet N. Y. invention. -_ It de- pay you Attor- Free, 12 articles worth $3. Al Exp. Scott, Cohoes, and the necessary steps to protect an for asking. Write: M. Labiner, Registered Patent scribes the procedure in Patent Office and tells about ney, 3 Park Row, New York. assignments, licenses and trade -marks, and gives many Scientific Engineer develops valuable ideas or inventions Manufacturing useful facts about patents which every inventor should guaranteeing working models. Nemeth, Consulting Engl... know. Many persons well versed in patent matters have 2 23d Street, New York City. Ex- pronounced the book the best of its kind they have ever neer, East To Order: Metal articles, Models, Tools, Patterns, it. Copy sent . Cleve- read. It is written so you can understand Electrical Devices, Tools, Dies, Models, Original De* Talbert & Talbert, Patent Lawyers, & Mfg.o.,acturing Searsdale Ave.,ed Cleveland, free upon request. signing Results our Specialty. Edward C. Forsberg. land SpecialtyfafCo.,entions 458 Talbert Bldg., Washington, D. C. Northfield- Ohio_ Ohio. 1140 Science and Invention for March, 1923 Novelties, Song Poems Wanted Crystal Gazing. Book 75e. Aloe Crystal.. Crystal Write the Words for a Song. Gazing Co., 122 Station "B." Hansel City, We compose music. Our Mo. Chief of Staff wrote many big song -hits. Submit your song -poem to us at once. New York Melody Corp., 412 Office Fitzgerald Bldg., New York. Aspirin Devices 1,11,,,,,,,,,,,,,1,11,11mm,,,,m,,,,mmIl,n,,,,n,,,,,,,,,,,,, m,,,1,11,11m,m,,,,,,.,,,,, ,,,,,,, m,,,m,,.n,mm. Save half on office Machines, Equipment, Addressers, Song Writers Multigraphs, Duplicators, Dictaphones. Pruitt Company, 172 North Wells, Chicago. errutttrrnmurrrromullirlIIIIImuirullOommummoureluoludno,,,,,,mmmmmmmm.,mmmn Write a Song! Any subject-you can do it. Bend Say "Bayer" and rkimer m words today-I will compose the music, Frank !Ladner. Insist! Patents 6018 Prairie Ave., Dept. 645, Chicago. Inventions Commercialized. Patented or unpatented, Write Adam Fisher Mfg. Co., 205 St. Louis, Mo. Stamping Names

Make $19 a Hundred stamping names on keyeheeks. Patents For Sale Send 25e for sample and particulars, Ex Kaytag Cohues, N. Y. Cc No. 1,407,175 Combination twineholder and advertising device; makes novelty moving display for counter. Pack- ers everywhere are looking for this sort of device to adver- Typewriters tise their product. Cheap to make, newest thing chance out, to make a fortune. Sell outright or royalty. Ad- Typewriters sold on payments. Free trial. Payne Com- dress B. W. Smith, Oroville, Calif. pany. Rosedale, Kansas. ,mmmmu m,mnumnmm mmm111m 1.mnnnmme mmm,nmI,mn11111mmnnmmmm,n,,,,,nm111111mm,mmm,nn111,1,,,,,,,, nnm,n m munn,n,nn11n,,,,,,,.n,,.u.n,n ,mm111111nmm1/1,1m.n, Personal Ventriloquism Astrology Revealed-Dime, birthdate and red stamp Ventriloquism brings 2,000 word trial reading. Two questions considered. taught almost anyone at home. Small Prof. Audrey, Section M-16, Box 834, Washington, cost. Send 2e stamp today for particulars and proof, D. C. Geo. W. Smith, Room M-743, 125 N. Jefferson Ave., Exchange Cheery Lettera with New Friends! Peoria, stamp, Send Ill. Betty Lee, Inc, 4254 Broadway, New York City. Exchange jolly letters with new friends. Leta fun! Send stamp. Eva Moore. Box 908, Jacksonville, Fla. Wanted to Buy Unless you see the name `Bayer" oro ,,,,,,,,, .. package or on tablets you are not gettin Cash for Old Gold, Platinum. Silver, Diamonds, Liberty the genuine Bonds, War, Thrift, Unused Postage Stamps, False Teeth. Bayer product prescribed by Magneto Points, Jobe, any valuables. Mall in today. Build Your Own Phonograph. Big saving. Pleaeant, sent Cash physicians over twenty-two years and prove d instructive return mail. Goods returned in ten days if you're not work. Complete Instructions, blue-prints, eta, satisfied. Ohio Smelting Co., 303 Hippodrome Bldg., safe by millions for absolutely free. Write today. Associated Phonograph Co., Cleveland, Ohio. COLDS HEADACHE Dept. AP -I2, Cincinnati, Ohio. TOOTHACHE LUMBAGO Perfection Phonograph motors, tone -arms, amplifiers, Full value paid for old gold, jewelry, watches, diamonds, EARACHE RHEUMATISM cabinets, hardware. crowns, bridgea, NEURALGIA PAIN, PAIN Highest quality, very low prices. Cat- dental gold, silver, platinum, gold or alog free. Federal Supply Co., Indianapolis, Ind. silver ore, magneto points, wer savings stamps, old false Accept "Bayer Build Your Phenograph. teeth. Packages held 4 to 12 days and returned If our Tablets of Aspirin" only. Quality phonoparts. Famous offer is not satisfactory, United Serenade Motors. Also original Perfection Motors. Elec- States Smelting Works Each unbroken package contains proper tric Motors, (The Old Reliable), 120 So. State Bt., Dept. 73. Chleago, tonearms, reproducers, amplifiers, case mate- Ill. directions. Handy boxes of twelve tablets rial, accessories. Free blueprints and building lnetno- cost few cents. Druggists also sell bottles tions. Big saving. Wonderful reaults. Prompt delivery. Catalog mailed for ten cents. Hoosier Mfg, & Supply Wireless of 24 and 100. Aspirin is the trade mark of Company. 321 Baldwin Block, Indianapolis, Indiana. .mm,nmmmmmmm,m..111 .m11mmmmmmm,,,,nmmmmm,mmmmmm,mmmmmmm,mmmnm,.NEM Baver Manufacture of Monoaceticacidester Boys, don't overlook this! The "Basco Babre,Deteetor. of Salicylicacid. Photoplays, Stories, Etc. Greatest detector ever brought out with molded base. Fully adjustable. See former advertisements in this publication or our catalogue. Detector with Galena Crystal complete, Wanted. Men and women ambitious to make money 50e; the same Detector with writing Stories and Photoplaya. Send Radiocite Crystal, 75e pre- for wonderful Free paid. Send for yours today. Radio Specialty Company. Book that tells how. Author.' Press, Dept. 131, Auburn, 100 N. Y. Park Place, New York City. FactsrEX other ,minnmm,mmm,m,mm,1, mm11nm,mmmmm,,,mmmnmmmmm,nmm,,,mnn ln,,mmmmm,mim-wA sex hooks don't dare discuss are plainly Attention! 50 Vacuum Tube Hook -Ups. The greatest told in Postcards and Pictures eollection of Vacuum Tube Circuits ever brought under "Where Knowledge Means two covers at such insignificant cost. These diagrams will be found Happiness." Creates a new 30 Actual Photographs of Washington, D. C. 35 cents, in the great "Rasco catalogue which contain° kind of married love. One postpaid. Nelson Carr, 3921 -7th St., N. W., Washing- raw materials and Darts in a greater profusion than any reader says: ton. D. C. other catalogue. 15e in stamps or coin will bring the -mmnmmmmrtnnnnmmnmmmnnmmwmnmmunummumm into mmmmmm mm,mm- catalogue to you. Radio Specialty Company, 100 Park It contains more real in- Place, New York City. formation than all other sex Printing books put together. How to Make Wireless We are printers of envelopes, letterheads, and imitation Receiving Apparatus. 100 pages From "Where' Knowl- Sent in plain cover, by re- typewriter letter work. -90 illustrations. Only strictly modern radio apparatus Send for price list. Colman are described in this book and the illustrations edge Means Happiness" turn mail, for $1.00, cash, Mercantile Co., 4421 Manchester Ave St. Louis, Mo, and de- emmmmmmmmm,nro m.mmmmmmmmmmmm,mmmmmm,m,mm,,,mmmmmmmm,mmain. scriptions are so clear and simple that no trouble will be Copyright 1921 money order,check or stamps. experienced in malting the instruments. Paper covered, Radio 35c postpaid. Experimenter Publishing Co., Book Dept.., COUNSEL SERVICE, Dept. 39, 257 W. 71st St., N. Y. Outfits and Supplies 53 Park Place, New York City. Agents Wanted in Every City to sell standard radio How to Make Wireless Sending Apparatus. DEAFNESS "IS apparatus on a liberal commission basis. A few stocking 100 pages I know was Deaf -88 illustrations. Written and published entirely for the because I arid had Head Noise agencies open to reliable parties. Delfelco, 12 Meeting wireless enthusiast wants for over 30 years. My invisible Antiseptic Ea Street, Pawtucket, R. I. who to make his own radio Drums restored my hearing and stopped Hea apparatus. Contains more information on "how to make Noises, and will do It for you. They are Tiri it than any other book we know of. Paper bound 3fegaphones. Cannot be seen when worn. Eifre-, 35c. postpaid. Experimenter Publishing Co., Book Dept., tive when. Deafness is caused by Catarrh or by Salesmen Wanted 53 Park Place, New York City Perforated. Partially or Wholly Destroyed Natural Drums. Easy to put in. easy to take How to Make Mots out. Are Big Profits-$250 to $300 a month selling high-grade Radio Frequency Amplifiers. This book "Unseen Comforts." Inexpensive. Write fors leather Fan Bella and Belting to Auto Accessory Dealers is for the more advanced amateur, showing the construction Booklet and my sworn statement of how I recov- and Garages. Full or time Write Monarch of the Radio Frequency Amplifying Transformer ered my hearing. part Belting and giving Co., 1270 Ontario St., Cleveland, Ohio. complete constructional data It shows the application of A. O. LEONARD Radio Frequency to amplifying units that the amateur 369, may Suite 70 Sth Avenue -+ New York Grail Big Profits-$300 to 400 a month selling Leather Belt - already possess and gives 15 hook-ups showing practically di )ng and Pulley Covering to Factories, Mill Supply and every use Radio Frequency Amplifying Transformers can he Hardware Jobbers. See our ads commencing Der. Issue put to. 32 pages, 15 illustrations; bound in beautiful two - "BOW LEGS and KNOCK- "Belting. Side Line or full time. Write Monarch Belt- rotor cover. Prepaid 25e. The E. I. Company, 233 Fulton ing Co.. Ontario Bldg., Cleveland, Ohio. Street, New York City, KNEES" UNSIGHTLY .mmmmm,mmmmmmmmmnmmmm,no,mm,mmmmmmmmmm,,,mmmmmnmmmlmm,llm,,,mn Send for booklet showing photos of men Wireless Course in 20 with and without PERFECT LEG Short Stories, Manuscripts Wanted Lessens. By S. Gernsback, A THE escarboura and H. W. Secor, E. E. Tells yott FORMS. hing you every - Earn $25 Weekly Spare writing want to know about "tt-ireless"-theor;, mac- PERFECT Time for newspapers, i ice and history. A clear, SALES CO. magazines. Experience unnecessary; details free. concise course on every N. Mayfield Press 1 hase of this subject. 160 pages 140 Ave., Dept. 50, Chicago.11l. Syndicate, 566 St. Louis, t -350 illustrations, 30 Mo. ables. Stiff cloth cover, $1.75, postpaid. Experimenter 1 'ublishing Co., Book Dept.. 53 Park Place, New York. Short Stories, poems, plays, ate., are wanted for pub- lication. Literary ARE YOU BASHFUL, TIMID Bureau, 165 Hannibal, Mo, The How and Why of Radio 1 1 1 1 Apparatus, m 1,,, 1, m, n 1,,,,l l,,,, m, mn,,,,mmmmmm, m,,,,, by H. W. Serer, m n , m,,, m m 1, n m m 1 3 1 1 ISelf Conscious. Embarrassed in mm n, m, 1, 1.1, m n 1 1 1m,,,,,, n n, n, E. Company. Let Ile tell E. This newest book on radio matters fills a dia- you how you can overcome these troubles and acquire inct gap in wireless literature in that, while the treat- confidence, Stamps and Coins 1 Poise, assurance and a magnetic personal- nent is made as understandable and as free from matbo- ity. Address The Vallee Science Institute, 1400 natIcs as possible, it at the eame time Broadway, New Desk 15. cealth incorporates a York, Stamps Free-Variety Packet, Foreign Stamps with cata- of technique and instruction for the Radio Ama- Logue -2c postage, Gray Stamp Company, Station E5, cur-the Radio Operator-The Installation and Designing Toronto, Canada. ,xpert-as well as teachers and students of the subject BUCHSTEIN'S FIBRE LIMB Stamps -20 Unused. All Different. n general. A very broad field has been covered Free. Postage 3e, 1 by is soothing to your Stratton paper. Quaker he author, at the same time giving a great stump-strong, Stamp Co.. Toledo, Ohio. i ,formation deal of cool, neat, light. Easy not found in other text books. If you are payments. Braces for Stamps. 50 varieties-Africa. Brazil, Peru. Cuba. engaged in any branch of the Radio or allied arts at all Mexico, etc., 10c. 50 ou will surely need this all deformities. different U. S., 25c; 1.000 mixed, I latest contribution to radio 40e; 1,000 i terature, which H. BUCHSTEIN CO. hinges, 10c. List free. C. Stegman. 5955 is destined to be found on every radio Send for Cote Brillante, St. Louis, Mo. can's book shelf before long. A glance Catalog Today Minneapolis. Minn. tot at the following of chapters gives but a very scant idea of California Gold, quarter size, 27c; half -dollar size, 530. t naive the ex - SEX KNOWLEDGE BOOKS Columbian nickel and catalogue, 10e. and useful radio knowledge provided in its instructive, authoritative, profusely Norman Sehub, t eat: The Induction Coil: The Alternating Box 146. Colorado Springs. Colo. 1 'ransfornrer: Current ADULTS! illustrated In natural colt s. etc. Not mmmm, ., mmmm moo,,s i,,nmumm,nun,ummmmmnm,,,mmmmnmmmmmmmummmmmum,m,wr Radio Transmitting Condensers: The Spark the cheap sort. Contains everything f laps: Radio -Transmitting Inductances; Radio Receiving ene should know both before and to r 'uners; Radio after marriage insure Telegraphy Receiving Condensers; Detectors: Tele - health and happiness. LARGE CATALOG FREE. hone Receivers: Radio Amplifiers; Construction of a E. SMETANA AND COMPANY. OWOSSO, MICH. I freot Reading Wavemeter and Deeremeter; Antenna Con- Wanted-Young men and women to learn s truction The Calculation and Measurement OLD MONEY WANTED Wireless Morse and mees; Appendix of Induc- $2 to $500 EACH paid for hundreds of old Telegraphy. Railroads and Wireless Companies t' containing very useful tables, covering er odd Coins. in great need of operators. Il subjects treated in this very Keep all old money as you may have VERY valuable We teach you quickly, and a unusual book. This coins. Procure positions at big salaries. Great opportunities n sweat of Radio Works, cloth bound in Vellum de Luxe, Send 10e for New Illustrated COIN VALUE BOOK, size for old Stamped and Hand Sewed, advancement. All. expensesD low; can part. Write has 160 pages. Size 4x6. Get posted. We pay CASH. Clarke Coin Co., Avenue day for free. catalog. School establishedearnc 1874. book. 6x9 inches. The o Appars- Dodge'soti s. Postpaid, 76, Le Hoy, New York. Telegraph Institute, "O Street. Valparaiso. Ind. n $1.7 5ExppeExperimenter Publishing iCo., Book ept., 53 Park Place. New York City. 1141 Science and Invention for Marche, 1923 RADIO FOR ALL By H. GERNSBACK Editor "Radio News," "Science and Invention" and "Practical Eleetrics" With over 130 illustrations and diagrams, and 12 photographs, 300 pages, size 8%" z 5%". which he can get all the information What the novice in radio needs is a book in a for him to understand radio telephony and telegraphy, to make or buy necessary to operate his set, and after he has receiving set suitable to his means, to know how and an understanding of the radio art, information that will enable him to advance All this must ordinarily be dug out of text -books, get the most out of his outfit. have all the Pamphlets and government publications, but the aim of this book is to the beginner will need from the time that he takes up radio. data and information that dabbler in It is a permanent, comprehensive reference book for the dyed-in-the-wool Radio. What the Book Is. with a refer- A combination of a radio course for the novice In radio telegraphy and telephony ence book for the more experienced amateur. Half a dozen books In one. For the Beginner. with drawings. The theory of radio carefully explained with all Description of and instruction for operating Instruments of receiving and sending sets, picture diagrams of the wiring of the apparatus. set, costing from $3.00 to $50.00. How to make your awn receiving technical diagram How to read diagrams; for every picture diagram there Is a corresponding using the symbols instead of drawings. How to tune sharply and eliminate Interference from other stations. How to protect your set from lightning and the laws regarding Installation. Explanation of time and weather signals. For the More Experienced Amateur. less than $50.00, How to make a practical vacuum tube detector, two stage amplifier set costing that will work. How the radio compass works. directional aerials. All about underground aerials, loop aerials and and Formulae for finding wave length; miscellaneous formulae for finding capacity of condenser wave lengths and their corresponding frequencies, other instruments. Tables of wire resistances, In- approximate wage lengths for different aerials, tuning coil data, and much more Invaluable formation. Special Features. time Lists of all the broadcasting stations in the United States and Canada for concerts, signals. weather reports, press, stock market reports, etc., with their call, wave length and time of sending. Detailed description of Washington weather signals and their translation. Description of a modern broadcasting station and its operation. Large map showing location of all II. S. radio telephone br.tadrasting stations suitable for hanging up in radio room. Collection of miscellaneous radio information for We amateur. Tl Completeon etc Booko0 of $ All Radio Information OU In Other Words. The information that you ordinarily have is dig out of government publications, text -books. PRICE POSTPAID 2 - pamphlets, etc., is handily combined in this one book. These Three "Little Wonder" Radio Books: You'll Need of Au- How to Make Wireless How to Make Wireless Design and Construction Apparatus dion Amplifying Transformers Receiving Apparatus Sending Radio and Audio Frequency Contains information on Type The 20 radio constructors how to make 30 different inter- know how DESIGN -CONSTRUCTION This boot: will be of great How TO MANE who wrote the book pieces of wireless sending ap- est to all radio amateurs. The IREEESS articles should be made from HOW TO MARE paratus from materials, easily transformers have never before been RECEIVING APPARATUS simple materials. WIRELESS obtained. described In print. The possessor Only modern apparatus is SENDING. APPARATUS Tells How to Make an Ex- of vacuum tubes cannot afford to such as Receiving do without this book. It will en- described, perimentalQuArc Set, kt ng able him to build the necessary set without aerial or ground, Arc Gap,K.V. W. amplifying transformers very read- magnetic detector, wireless re- Transformer, Oscillation ily. The book Is printed on goal lay, wireless lecture set, etc., Transformer, Photo Phone, paper and has an attractive cover etc. Book has 100 pages, each in two colors. Paper bound. Size, 'reel )5<[i 1 (I etc., etc. 90 illustrations, 7 a 5 5 inches by 7 Inches. Contains 6 x 7 inches, Book has 100 pages (size, many Illustrations, diagrams and many full pages, paper bound, inches). 88 illustrations, paper working data. in two colors. cover printed In two colors. Price 35 Cents Price 35 Cents Price 25 Cents A Thousand and One Formulas By S. Gernsback

A Laboratory Hand Book for the Experimenter and for Everyone who wishes to "do things." A Book brimful with very important and priceless Information. The recipes and formulas are classified in such a manner as to be available quickly, without long research. Invaluable for Students, Engineers, Physicians, Experimenters, etc. Here are sume of the chapter headings: Cements and Glues; Composition of All Kinds; Glass and Glassworking; Inks; Leather Polishes; Metal -craft; Perfumery, Soaps and Extracts; Pho- tography; Blue Print and other Paper; Plating; Pyrotechny; Polishes and Stains; Varnishes and Paints; Various Cleaning Formulas; Wood -craft; Chemi- cal Laboratory Hints and Experiments; Mechanical Laboratory Hints and Experiments; Electrical Laboratory Hints and Experiments. There are a score of tables and hundreds of illustrations and Diagrams. It contains 160 pages. The paper has been specially selected to stand rough handling in laboratories. Size, 6 x 9 inches. Cloth bound In Vellum de Luxe, stiff covers, hand -sewed, gold $1.75 stamped, each This Wonderful Volume of Formulas- You Should Have It In Your Home DEALERS-Ask for wholesale discount EXPERIMENTER PUBLISHING CO., Inc. : 53 Park Place, New York 1142 Science and Invention for March, 1923

1I!Illllllllllllllllllllllllllllllll I I I I I I I I I I I I I I I I IIIIIIIIIIIIIIIIIIII IIIIIIIIII IIIIIIII I1111111! IIIII I111111I IIIIIIIII II111111I IIIII II Ilill I I I I IIIII111111III IIIIIIII IIIIIIIII IIIIIIIIIIIIIIIIIIPIIIIIIIIIIIIIIPIII II I1111111IIIIIIIIII IIIIIIIIIII I IIIIIIIIIII Illlllllllllltflllllllllfhllflllllllll II1111111111111211ifiMIIIMILLIII

EVERY BOY WHO IS INTERESTED IN RADIO CAN TAKE ADVANTAGE OF OUR SPECIAL OFFER

EVERY BOY HAS A FEW SPARE HOURS EACH WEEK and can easily obtain a few subscribers to PRACTICAL ELECTRICS. On this page you will see the special rewards we will send you for only one subscription. You can easily earn every one of them. They will be sent you ABSOLUTELY FREE

PRACTICAL ELECTRICS is the electrical magazine for every- one. It is the only electrical magazine a boy can understand. It has a regular department for beginners, but is just as interesting for the experimenter, the electrician, and the electrical engin:er. There are articles each month by students, experimenters and famous electricians. The entire progress of the month in electrics is set forth in its pages. PRACTICAL ELECTRICS is one of the most interesting elec- trical magazines published. It contains no long, dry technical articles. Every article is completely illustrated. There are hundreds of illus- trations, plans, drawings, charts, etc. On the opposite page you will find complete description of each reward. PRACTICAL ELECTRICS is only $2.00 per year [12 Numbers] w ...... :...::: .: HOWW(E SS G (Canada or foreign 50 cents additional) e`sVP Q4° SENDING APPARAT( EVERY BOY SHOULD HAVE IT! All articles are written in plain, every- day language. If you need a sample copy to show we will send it free of cost. SEE OPPOSITE PAGE FOR DESCRIPTIONS

--,cffiKtNG-N; 2 How * ,, Detector and units

Af ABSOLUTELY FREE FOR A FEW HOURS' SPARE TIME WORK. READ OUR SPECIAL OFFER AND ACT AT ONCE. Science and Invention for March, 1923 1143

111111111111111111111 1Lä 1 11110111 111111 II pIIPID11111IIIIIIIIIIIIIIIIIII1IIIIIIIIIIIIllI11fII11 II 1 111111111111 II 1111 11111 I III I I I I II II 11111 II I I III Ill Ill Descriptive Details of Rewards We will send you your choice of these rewards. ONE REWARD FOR EACH SUBSCRIPTION for one year.

REWARD No. 1 REWARD No. 8 RADIOGEM 2 RADIOPHONE DIAGRAMS AND HOOK-UPS A complete crystal Radio Receiving Set, will receive up to 25 Of Crystal and Audion Receiving Circuits, Amplifier miles. The outfit consists of all the necessary wire, contact points, Circuits, Regenerative Circuits, Sending Circuits detector mineral, catwhisker, tuning coil, instruction book, etc. Symbols, When you have constructed the Radiogem, all you need is an aerial with Key Chart of and Pamphlet and a phone. "HOW TO READ DIAGRAMS" All 20 diagrams are printed on heavy paper, each sheet size 8%a x 11%. inches, and together with Key Chart of Symbols and pams REWARD No. 2 phlet, "How to Read Diagrams," are contained in a heavy two- MICROPHONE BUTTON color printed envelope, size 9 x 12 inches. The button may be used to amplify Radio Signals by using it in a local circuit. It should be mounted on the diaphragm of a REWARD No. 9 telephone receiver connected to the radio set and in circuit with a WIRELESS COURSE IN 20 LESSONS battery and a telephone induction coil. You can easily make a highly sensitive detectophone by using a Microphone Button to By S. Gernsback, A. Lescarboura, and H. W. Secor, E.E. collect the sound waves. You can build your own outfit without (10th Edition) buying expensive equipment. Think of the fun you would have A Course that tells you everything you wish to know about with such an instrument! "Wireless," starting in lesson No. 1 by explaining the Principles of Electricity. By simple, easy stages, this wonderful Course takes you into "Wireless" by the use of such simple language so skill- REWARD No. 3 fully used that of necessity you must understand every word. EXPERIMENTAL ELECTRICITY COURSE IN Size of book is 7 x 10y inches, 160 pages, 350 illustrations, 30 20 LESSONS tables, Limp bound. By S. Gernsback and H. W. Secor, E.E. A Course on the theory and practice of Electricity for Experi- REWARD No. 10 menters. One of the most complete and comprehensive treatises of this special subject ever published. Written by the same authors THE HOW AND WHY OF RADIO APPARATUS best electrical text book on By H. W. Secor, E.E. as the famous "Wireless Course." The newest on radio the market. Size of books is 6 x 9 in. The book contains 128 This book matters fills a distinct gap in wireless Limp bound. literature in that, while the treatment is made as understandable and pages, and more than 400 illustrations. as free from mathematics as possible, it at the same time, incor- porates a wealth of technique and instruction for the Radio REWARD No. 4 Amateur-the Radio Operator-the Installation and Designing Ex- pert-as well as instruction for teachers and students of the subject Complete Patterns, Diagrams and Instructions How in general. to Make Your Own 160 pages, 6 x 9 inches. Limp bound. RADIOPHONE CRYSTAL SET PATTERN No. 3 REWARD No. 11 Consisting of a 4 page illustrated Direction pamphlet, size 81/4 x 11% inches; one blueprint pattern, size 16 x 12 inches. All A THOUSAND AND ONE FORMULAS contained in two-color printed envelope, 9 x 12 inches. By S. Gernsback A laboratory hand book for the experimenter and for everyone who wishes to "do things." A book brimful with very important and REWARD No. 5 priceless information, collected and selected for years. Invaluable for Students, Engineers, Physicians, Experimenters, etc. Complete Patterns, Diagrams and Instructions How It contains 160 pages. The paper has been especially selected to to Make Your Own stand rough handling in laboratories. Size 6 x 9 inches. Limp SHORT WAVE REGENERATIVE bound. RADIOPHONE SET PATTERN No. 1 REWARD No. 12 Consisting of a five -page illustrated direction pamphlet, size 8%z x 11V, inches; one blueprint pattern, size 16 x 22 inches, and one (All Three Books) blueprint pattern, size 17.1/4 x 22 inches. All contained in a heavy HOW TO MAKE WIRELESS RECEIVING APPARATUS two-color printed envelopes, size 9 x 12 inches. The 20 radio cohstructors who wrote the book know how articles should be made from simple materials. REWARD No. 6 Book has 100 pages, each 5 x 7 inches, 90 illustrations, many full pages, paper bound in two colors. How Complete Patterns, Diagrams and Instructions DESIGN AND CONSTRUCTION OF AUDION to Make Your Own AMPLIFYING TRANSFORMERS DETECTOR AND AMPLIFIER RADIO UNITS PATTERN No. 2 Radio and Audio Frequency Type Consisting of a four -page illustrated direction pamphlet, size 8% This book will be of great interest to all radio amateurs. The x 11% inches; one blueprint pattern, size 16 x 18 inches, and one transformers have never been described before in print. blueprint pattern, size 13,A x 15 inches. All contained in heavy, Size, 5 x 7 inches. Contains many illustrations, diagrams and two-color printed envelope, 9 x 12 inches. working data. HOW TO MAKE WIRELESS SENDING APPARATUS REWARD No. 7 Contains information on how to make 30 different pieces of wire- 14 RADIO FORMULAE AND DIAGRAMS less sending apparatus from materials easily obtained. All formulae and diagrams are printed on heavy paper in black Book has 100 pages (size 7 x 5 inches), 88 illustrations, paper and blue; and contained in two-color printed envelope 9 x 12 inches. cover printed in two colors. PRACTICAL ELECTRICS CO., Inc., 53 Park Place, New York, N. Y. GENTLEMEN:-Please send PRACTICAL ELECTRICS for one year (12 numbers) to each of the following addresses: Name Street Address City and State

Enclosed you will find subscriptions at $2.00 each, making the full sum of $ (For each subscription to go to Canada or Foreign addresses 50 cents additional must be added.) Also please send me the Rewards (one for each subscription) numbered as follows:

My Name Is Street City State

11111111111111IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII11111111111 1144 Science and Invention for March, 1923

Get This Wonderful New Book About LOUD - TALKERS Tza's ,te. N, EX°EPIMEN 0 HOW TO BUILD THEM

o A by H. WINFIELD SECOR r Associate Editor of Science & Invention > i ;y 25 cents, postpaid This book describes how to build two distinct and different types of radio loud -talkers, which can be built with either 1 electro -magnetic field to be excited from storage battery, as well as permanent magnet field requiring no separate bat- ßS tery excitation. The third chapter deals with improvised tItE -HEM loud -talkers and gives clear and complete instructions on ID gtlCl how to build suitable horns for use with radio receivers of p b y E.E. the Baldwin and other types.PSeveral elaborate hook-ups N4iINEÍ[lC%SEC:PaÈNt,ONE¡rlttlP SCIENCE ` are given of the author's own radio receiving set, comprising pSSdIiAE one stage of radio -frequency, detector and three stages of audio -frequency amplification, together with all the connec- --' PRtE' tions for the loud -talker. I ; 25'' Complete data is given for all the parts of the loud -talkers, C _ 1 c, including the field magnet windings, as as the diaphragm ' o. ciT - well óN grE. NE.' or moving coil windings, and also the step-down transformer 1,33TO to be connected between the vacuum tube amplifier and the loud-talker proper. In preparing these designs the point has been constantly kept in mind to use the simplest parts possible, so that practically anyone can build a successful loud -talker equivalent to the commercial types costing $40.00 or more. Even where the experimenter does not possess the skill or the time to make all the parts himself, which are really few in number, he may save a great deal of money, or at least half the price of a commercial loud -talker, by having the difficult parts made in a local machine shop, and then assembling them and winding the coils himself. Circuit connections and data for the size of wire, etc., are given for placing the loud -talker on a separate floor or in another part of the house not occupied by the radio receiving set. A very valuable book, giving data which cannot be obtained anywhere else and which has not been published before. 64 pages, 25 illustrations, bound in beautiful two-color cover, size 51 x 71 inches; Price prepaid, 25 cents Have You a Copy of These Two Books? HOW TO MAKE RADIO -PHONE RADIO FREQUENCY AMPLIFIERS RECEIVING SETS AND HOW TO MAKE THEM By ROBERT E. LACAULT 2 5O Associate Editor RADIO NEWS By JOHN M. AVERY A non -technical book for the .Á beginner. Gives complete con- This book is for the more ad- s structional data on the building of .. U.PY N01 vanced amateur, showing the con- ,, . ;,,,t -.Is YMf E%DEPMENT[0. complete Crystal Detector Set, ° ° a. struction of the Radio Frequency (`t)(/i PRE HOWW Ta M egE Tuning Coil, Loose Coupler and a CY AQQNééÌE Single Audion Tube Set with Am- AmplifyingALINTransformer and km giv-RSHnw SETS plifying Units. It furnishes all ing complete constructional t0 MAKE THEM data.141 ECEwtNG enYP dimensions and working drawings JUHN an'consmucnnN It shows the application of Radio M' AVERY oMru c mncavrs of every part that must be con- 0.,Latcwu?,K Frequency to amplifying units a,,...... strutted by the amateur. Written in plain, simple language that any- that the amateur may already pos - one can understand. The opening sess and gives 15 hook-ups showing chapter gives a complete descrip- practically every use Radio Fre- tion of the theoryof radio and tells quency Amplifying Transformers t dk what it's all aout, teaching the äßi principles of wireless so that the can be put to. constructor knows what he is doing. z Pages,z Illustrations48 Pages, 26 Illustrations 3 5 r - sn a E, c öµ "^ Bound in Beautiful Two -Color Cover Bound in Beautiful Two -Color Cover Size, 5%x7% inches. Prepaid 25c. Size, 5%x7% inches. Prepaid, 25c. E Order from your dealer-or direct from us _. FULTON STREET THE E. I. COMPANY NEW ZYORK CITY N. Y. 1

THE PERIODICAL PRESS, NEW YORK Let These Guides Solve Your Problems

; 1_.W._ s I t_- ,a NAWKII'S IIAWKINS :NAWKIhS; KÄwKIs!i jNAK t flKI1 11.111110Sa y1w'KI,S HINKIVS Gr._ F(TRI(AL I.LI:(TRIfII [LETRa , EIEQRI.(al FIE(TRI;AI E.LELTRI(a( ,EEE(TRI(aE ELEqRILAI; i ;iEA jCU19F-:Ql GUIDE (CUIDr CUIDJ 'GUIDE; !GUIDE, LIIDE 'CUIIIEE t =: N °6; .v_. v°8 Nllk`Il 3°¢ f'9'L___., :.__J °L._.._:. z-_. RqILwAYS{ .1 A.C. ' Ac i ac .i IMpNA WIRING 1, LENE E SYSTEMS WIRINL TELEGRAPH :AlTER9ATIK MOTORS MoriDN IGISTRIBUIiLA° 1 OYÑAMCS CIRCUIT :; POWER WIRELESS PICTURES CURRENTS RARSE RMEA MOTORS_ SYSTEMS BREAKERS' STATIONS k BELLS ApTOrRES 1:1.EPNONE. NSTAUMtNT^ STORAGE ' AN0 -OhYGTERS; MEASÜRINE f fll6tíllti 1GNIT1 _ECTIFIER i4STRUME415. WORK IND . 1 TESTING BATIíRiL _ __, 4 Fr-r= -z.1 ) .f. i t\ I [F L:. ! O,. i 2533 % E t8o3 Ir , . \ s,- 697 .!s7 581 ) {" 1I I. 1 rr \ i8e 2100 57 E 99 6. 1 'lcc 3 '.bt ì n . { '0" .=='I ;=f;-. ` ^ `- - -! Ell cult II your fi er ends HAWKINS ELECTRIC L GUIDES Ms 3500 PAGES $1 A VOLUME SEND NO MONEY-SEND ONLY THIS COUPON 4700 PICTURES $1 A MONTH more money and better Know the facts in Electricity. They mean AUDEL &. CO., Hawkins Guides tell you all you need to know THEO. position for you. Ave., New York City about Electricity. Every important electrical subject covered so 72 Fifth Easy to study and apply. A complete, Please submit me for free examination, HAWKINS you can understand it. at working course, in 10 volumes. Books are pocket size; ELECTRICAL GUIDE (Price $1 a number). Ship practical I agree flexible covers. Order a set today to look over, once prepaid, the 10 numbers. If satisfactory, seven days and to further mail LEARN ALL ABOUT to send you $1 within you $1 each month until paid. Magnetism - Induction - Experiments - Dynamos-Electric Ma- chinery-Motors-Armatures-Armature Windings-Installing of Management Dynamos-Electrical Instrument Testing-Practical Name of Dynamos and Motors-Distribution Systems-Wiring-Wiring Diagrams-Sign Flashers-Storage Batteries-Principles of Alternating Currents and Alternators-Alternating Current Motors-Transformers- Converters-Rectifiers-Alternating Current Systems-Circuit Breakers- Occupation Measuring Instruments-Switchboards-Wiring Power Stations-Installing -Telephone-Telegraph-Wireless-Bells-Lighting-Railways. Also many Modern Practical Applications of Electricity and Ready Reference Index Employed by of the ten numbers. SHIPPED FREE Not a cent to pay until you see the books. No obligation to buy unless Home Address you are satisfied. Send Coupon now-today-and get this great help library and see if it is not worth $100 to you-you pay $1.00 a month for ten months or return it. Reference - S 1 Mar.

Free Proof That Cooke TrainedMen Let us send you Free, this big package of "Vital Facts" showing what "Cooke Trained Men" earn, the big opportuni- ties Electricity offers and how you, too, DO can earn 53,500 to 510,000 a year. The Earn coupon will bring it FREE. $3,500to X10,000AYear Electrical Experts-Trained Men are in big demand at the highest salaries ever known. The opportunities for advancement and a big success are unlimited-positively unlimited. The Electrical Industry faces a big shortage of trained men. It needs you and will pay you well.

What's Your Future? Be an Electrical Expert It's a shame for you to earn less than $100.00 andGet This Big PayYourself a week. You ought to earn more. You can do it, too, when you are Today even the ordinary electrician, the screw driver kind, is making money-big backed up with my money. But it's the trained man-the man who knows the whys and wherefores of training - the training Electricity-The Electrical Expert who is picked out to boss the ordinary electricians- that makes "Big Pay to boss the big jobs -the jobs that pay $70.00 to $200.00 a week. Fit yourself for Men." Don't be con- one of these Now. tent with an ordinary big jobs-Begin job paying anywhere from $3.00 to $10.00 a Age or Lack of Experi- I Give You A Real Training day, with no future to ence No Drawback As Chief Engineer speak of. Strike right of the Chicago Engineering out-hold the job you've You don't have to be a College Works I know exactly the kind of training a man got and prepare for a Man, you don't have to be a High needs to get the best positions at the highest salaries. better one - prepare for School graduate. My course in Hundreds of my students are now earning $3,500 to a "he man's job" in the Electricity is the most simple, thor- $10,000 a year. Many are now successful ELEC- $3,500 to $10,000 a year ough and successful in existence, TRICAL class in the greatest pro- and offers every man, regardless of ENGINEERS. fession in the world. I age, education, or previous experi- FREE -Electrical Working will show you the way. ence, the chance to become, in a Outfit -FREE very short time, an "Electrical Ex- I give each student a Splendid Outfit of Electrical Radio Course pert," able to make from $70 to $200 Tools, Materials and Measuring Instruments abso- FREE a week. lutely FREE. I also supply them with drawing Your Satisfaction Guaranteed Outfit, examination paper, and many other things My new $45.00 Radio that other schools don't furnish. You do Course, just completed, So sure am I that you can learn elec- PRACTI- tricity-so sure am I that after studying CAL WORK-AT HOME. You start right in after given FREE when you en- with me, you, too, can get into the "big roll for the Electrical money" class in Electrical work, that I the first few lessons to WORK AT YOUR PRO- Course. Two courses for will guarantee under bond to return every FESSION in a practical way. the price of one. Two pro- single Jenny paid me in tuition if, when fessions open to yon. you hr ,re finished my course you are not satisf_ed it was the best investment you Get Started Now -Mail Coupon ever made. I want to send you my package of "Vital Facts," ti including Electrical Book and Proof L. L. COOKE, Chief Engineer Lessons FREE. CHICAGO ENGINEERING WORKS These cost you nothing and you'll enjoy them. Make Dept. 22, 2150 Lawrence Ave., Chicago, III. the start today for a bright future in Electricity. Dear Sir-Send at once the "Vital Facts" containing Sample Lessons, your Mail the coupon-NOW. Big Book, and full particulars of your FREE Outfit and Home Study Course -all fully prepaid, without obligation on my part. L. L. COOK!. Chief Engineer Name. Address. CHICAGO ENGINEERING WORKS Occupation. Dept. 22, 2150 Lawrence Ave., Chicago, Ill. The Cooke trained man is thè'ßiPaijÌnart