Popular Science Monthly 1918-06: Vol 92 Iss 6

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Reg US.PatOff NOTICE TO READER When you finish reading this magazine, place a one-cent stamp on this notice, mail the magazine, and it will be placed in the hands of our soldiers or sailors destined to proceed overseas. NO WRAPPING—NO ADDRESS i |

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SENECA CAMERAS IKE the Indian Tribe, after which they are named, Seneca Cam- eras are thoroughly American. They want to help win the war by taking pictures here at home for the Soldiers in France and in the Training Camps. Seneca stands for picture making satisfaction. Get a catalog from your dealer and choose your model. Home pictures will cheer your soldier. Seneca Camera Mfg. Company 157 State St., Rochester, N.Y. U.S.A. Seneca Folding Scout : w. 3A Size Takes 314 x 5/4 in. Pictures "13

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Popular Science Monthly HIS MASTERS VOICE tor quality, al le eh is oe ao Victor Records -the living evidence of an artists greatness What is it that makes an artist famous? That wins the applause of appreciative audiences? That establishes an en- viable reputation as a great artist in the hearts of music-lovers? The answer is indelibly inscribed on Victor Records. They are the living evidence of an artist’s greatness. They repro- duce the art of the most famous singers and instrumentalists with unswerving fidelity. With the Victrola you can enjoy these superb interpreta- tions at will right in your own home. But only with the Victrola—for the world’s greatest artists make records for the Victrola exclusively. Any Victor dealer will gladly play for you any music you wish to hear and demonstrate the various styles of the Victor and Victrola—$10 to $400. Period styles to order from $375 to $950. Saenger Voice Culture Records are invaluable to vocal students—ask to hear them. Victor Talking Machine Co. Camden, N. J., U.S. A. Berliner Gramophone Co., Montreal Canadian Distributors Important Notice. victor Records and Victor Machines are scientifically coordina- ted and synchronized in the processes of man- ufacture, and their use, one with the other, is absolutely essential to a perfect reproduction. New Victor Records demonstrated at all dealers on the Ist of each month Victor Supremacy Victrola XVI, $265 4 Victrola XVII, electric, $325 _Mahogany or oak When writing to Adv_rtisers please mention Popular Science Monthly

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Popular Science Monthly SSSR mG 5¢ “Short Cuts to Gocd Carpentry”= ( Vol.36, CypressPocket Library) 48 pages of authoritative in- struction (simple, clear and stimulating) fully illustrated and with big Supplement, 24 x 36 in. with detailed Work- ing Drawings that show how to make twelve‘‘hard jobs’’ easy, safe and éco- nomical of both labor and Lumber. Read what “Rural Life,’’ (Roches. ter, N. Y.) says of “SHORT CUTS to GOOD CARPENTRY” “Tt is a guide book for the man or boy who can handle a saw or hammer and wants to know how to use them to the best advan- \s KE topics pertain- ing tothe Ss Sa house and 4 — Ss = WW je about barns. Sent free with 1 } f ef So 2S our compliments. SS WE TRUST YOUR & OWN JUDGMENT and SELF-INTEREST to INSURE CYPRESS on YOUR job. ‘‘The Wood Eternal’’ keeps values coing up by keeping the place from running down.” x SIRS mann ~ AWE 1,1’ ‘Wwe Then rlanning 2 Mansion, a Bungaiow, a AAWWAAAPA AAT ANI AAA, AS NN \* yee pare’ 1. n Slecping-Porch or just a Fence, remember — S\ INN \\ VP, et SS nou BUILD BUT ONCE,””_ TRY IT. - - - enna \ at your service with Reliable Counsei, Sy 4 N TAS WS ud fet oor “ALL. ROUND HFI.'S DEPARTMENT” kelp YOU. Our resources are SOUTHERN CYPRESS MANUFACTURERS’ ASSOCIATION 1249 Heard Nat'l Bank Bldz., Jacksonville, Fla., or 1249 Hibernia Bank Bidg., New Orleans, La (Please address nearest office) 7 FiY NY TNSIst ON CYPRESS AT YOUR LOCAL DEALER'S. IFHEHASN TIT. SES USANOW LUM? Es When writing to Advertisers please mention Popular Science Monthly mn, eel | | ee

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Popular Science Monthly

Popular Science Monthly 225 West Thirty-ninth. St., New York

Waldemar Kaempffert, Editor No. 6

Volume 92 Contents for June, 1918 AERONAUTICS Air Raiders Don’t Like These Lights........... The Penguin Seapiane............+4+ Parachute Breeches.......... ees cccvccccevess Parachute Safety Device for Airplanes How the French Developed a New Battleplane ... 916 AGRICULTURAL SCIENCE

Water-filled Roller. ..... ese escecenecscccccs 834 Making Money Out of Rabbits........... wide 835 Catching Grasshoppers by the Bushel........ vos O38 Individual Protective Housing for Delicate Plants 848 Soap and Fertilizer from Dead Locusts.......... 848 Submarine Saws for Water Weeds.............. 86 Plowing with Coal-Gas on English Farms........ 862 Making It Easy for Old Dobbin to Eat.......... 879 Every Farmer ne Be His Own Soil Chemist..... 896 Kneeling Made Comfortable by This Pad....... 909 Making a Wind-Proof, Rain-Proof Chicken House 914 The New Dandelion Extractor................. 917 Making a Gas Attack on the Pesky Ground Squirrel 918 ARCHITECTURE Introducing the Busy Honey Bee—Ecclesiastical PUR sere ioe ie plc aia iero nace ecu opie winarevasn sais 824 Platform for Loading Wagons... 864 Is a Zi Here Is a Zigza laa Leask tlhe oeer ieee... on Mexican Corn This Is a Farm Gate—No Doubt of That........ 872 PGameulemed WeElRCUI sos. 6:66.6.6:5.0:0.60 0 o.0e-e:s 896 The “Little Church of the Flowers” ........... 906 ASTRONOMY When the Moon Darkens the Sun............... 849 Thirty Million Collisions in a Day............. 915 CHEMISTRY The Process of Making Parchment Paper........ 806 Making Soap from Table Refuse................ 837 Inexpensive Aluminum Polish.................. 923 ELECTRICITY Electric Sparks Peel the Tomatoes.............. 897 Saving Time in Insulating Electric Cables....... 918 What Is the ‘““Dead’’ Lamp on a Series Circuit? 920 Cleat for Holding Temporary Electric Wires. .... 947 An Electrically Driven Toy Tank That Goes PA MERE SEN oo, sittin b's Gio 5 eke, Grass ona. a sicloserons 47 Durable Terminals for Electrical Conductor Cords 948 Shocking Device That Works on the Commercial DO aco aes 6 Scasis iste carare oie savers aierees rat 948 Locating and Repairing Short-Circuited Armature eg a SRR sec aa i a 948 Electrical Devices and How They Work......... 949 Combined Electric Night-Bell and Flash-Light... 952 Self-Translating Telegraph Line for Amateurs.... Interesting Method of Learning the Telegraph RMON Cee Co) seas So wis ako ohelg ¢ = arent veus-s 6 miavtie ces Home-Made Electric. Furnace for Heating with Arc LILO os Rare ce i ar ae nen Simple Way of-Cutting Mica V-Rings to Fit on an 5 UTA Re ee 955 Holding Clip for Making Tests on Spark Plugs. ... Controlling an Oil Cup with an Electromagnet.. 956 HOUSEKEEPING MADE EASY Housekeeping Made Easy................... 840-41 You Can Carry It in Your Hand and It Saves Fuel 880 Making Window-Cleaning Safe................. 903 INDUSTRIAL PROGRESS Old Tin Cans — in Milady’s Costume........ 825 No Very Great Danger in Makin Explosives..... 832 This Press Makes Two re Bricks a Day... 837 Making Use of Tomato Seeds and Skins......... 839 Ideal Industrial Locomotive.................... 851 MIMICS DOUIRACES, 60. oe koe ooo cw che oencncc: 852

MECHANICAL ENGINEERING Page Saws Without Teeth to Cut Through Metal...:.. 824 Unloading Freight Cars by Machinery........... 833 Building a Subway Under a Subway............. 844 MecharCal ipl pes. 5 ccc. 6 wonacmanecdecis caste 853 Wafting Five Tons About as Though They Were BY A ON REE erent enein hy ee ee This Moving Van Loads from the Side........... 876 Holding the Screw to the Screw-Driver........... 897 Flexible Coupling Takes Side Strain Off Shafting.. 908 Making Water Pump Itself..................2. 919 MEDICINE, SURGERY AND HYGIENE Old Age Is Not a Matter of Years, But of Recupera- tive Power ee Bathtubs tor the levees oo... os cuk seven netess 836 Repairing the Ravages of War............... 874-75 Beware of the Perils of the High Heel............ 905 Fasting Is Not What It’s Cracked Up to Be...... 917 MILITARY AND NAVAL SCIENCE The Martyr Pigeon of the British Navy......... 805 The Story of a Wickes PRS Neos 6 ola bene cians are 828 Death Traps in Seemingly Unoccupied Fields... 851 Running Down a U-Boat with a Sub-Sea Barrage 854 This Baby Caterpillar Tank Isn’t Dangerous.... 856 Mechanics of the Red Cross............ee000: 858-59 The Hawks of the Royal Flying Corps........... 860 Signaling System Is Employed in American Barrage 865 Forts Built by Vauban Are All That Remain of NM NMIIOT 65556 aa 06 écago let ofp: «Reape diakalaba ave Wet AS reas 865 Machine-Gun Practice with Painted Targets..... 866 Wouldn’t This Puzzle the Enemy ?.............. 871 The Moon and the Earth Help the French to BPPVOCO: COROT E RIO... cic-c:ce wie o's siete ioiw crsie-orereie 872 Learning to te a Sailoron Dry Land............ 877 Going “‘Over the Top” with the Soldiers at Camp re 877 MBE EUG fo isc! sk ats core. c.6) a. ciswerat skola ssc xxl 895 Trench-Dwellers Cherish the Barber’s Ministra- LOTS RRR Re SR RT PR re NA RECN Ke 9p hh 899 Nerve Shock Due to Detonations Less Wearing PEMNK. NOME REBRIN 5. 5.0.00 vce rae-Dieiee a necasers 901 oy Used as Protective Covering Even on DUO IRUEENEE oo. <5 6:c.0: 01 a4osahe-4i'g/ 670 iaolecase eearatetoerctes 907 The Fifty-seventh Variety of Armor for the Modern Soldier Appears.........0ccecceeeees 920 MOTOR VEHICLES AND THEIR ACCESSORIES Garage Doors That Save Space and Time.... ... 842 An Automobile That Got Its Power from the Street INRIOB Ce dc dulare tui artigto cine ote atametcon ie wane. 843 Who Won the Motor Contest ..........6....05- 849 A One-Wheeled Motor Tractor.............205- 850 Hoisting-Frame for Automobiles ............... 864 riving Your Car Through a Stream of Oil ...... 878 No Footprints Are Left by This Lawn-Mower.. 880 Automobile or Railway Car—Which Is It?....... 887 Extending the Use of the Sidecar................ 887 Automobiles, Motor-Trucks and Accessories. . .888-89 Sleep in Your Auto and Hang Up the Baby...... 892 Notch the Curb to Keep Out Autos............. 894 Putting Overalls on Autos for Protection......... 894 A New Use for the Little Tractor: Spotting Freight Cars for Large Plants................ Auto Bearings and How to Care for Them Properly 922 NATURAL SCIENCE How a Woman Makes Money by Putting Nature Under Glass 83 Nature Carves a Queer Snow-Cave in the Cali- RGUHIM I RMORERB it fet tan ee Soa rre een Care arias 865 An Alibi for the Bee in the Orchard.............- 870 Something to Lose Sleep Over—Can Fish Hear?.. 886 The Queer Forms of Some Flies................ 886 The Secret of the Wily Snake’s Sinuous Glide. .... 892

Copyright, 1918. by the Modern Publishing Company

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Popular Science Monthly CONTENTS FOR Page | PHOTOGRAPHY AND MOTION PICTURES A Derby Hat Used in Place of Camera Tripod.... 868 No Double Exposures with 1his Device.......... 893 Pee hing Holland in California............ 912 ding Ph hotographic Plates from Tray Bottom.. 942 Meine Photographic Timer Out of Watch....... 945 PICTURE PAGES Teaching Our Soldiers the- Hand -to- Hose ET eee LET EAE TEE TE oodenware and Hardware Hats Sterilizing Wagons for the Army.... he Army’s — Laundry NS ee ee eres 81 Five Million Tianeae Cars, a Total of 120 or , | orse-Power oe Making Artificial Limbs for Soldiers........... 818-19 peeks Ganme Mirds Fey .-........ 2.20 ccceees 820-21 Airplane Picture of German Lines............ 822-23 PRACTICAL WORKERS’ DEPARTMENT How to Make an Air Operated Metal Punch for the ” ho Keeping Foods and Eggs Fresh on Camping Trips 921 Auto Bearings and How to Care for Them Properly 922 ep. ma | Hammer Handles with Steel Strips. 923 JUNE—Continued —- RAILWAYS rig een Fuetaeteiel ys: peo . ee 851 unnel Is Coming. On with the Fresh-Air Mas Chinese Women Working on Rail Sedna: aa i ; ~~ ne Railways That Run ym he BVREBT ssc5 5 s.+\ acc nee 8 oes a Locomotive Wheel Travel Slower or Faster meen Bie Seeine..«. 6 os. ck ce os eke. Page Solving the Railroad Problem................./ oe | Turning a Bicycle Into a Railway Hand Car... || 914 SHIPS AND SHIP BUILDING Feige a Sunken Ship with Cork.............., 803 How the Boilers of the “ ‘Bear’ Were Salved...... 873 * "SPORTS AND PASTIMES Cut the String, Blindfolded, and Win Tobacco. ... 824 Modern Camp Comforts..................... 26-27 Aquaplane Racing Full of Genuine Thrills..... |. 83] A Giant Strawberry Shortcake................. 832 Combining Two Favorite Sports—Croquet and “Dea Pe SEES inte ee gle REGRET: - 834 Teams of Motor-Cycles Have a Tug-of-War.. 836 Ornamental 7 gga Pools Take Place of Qld SNPISURNIE MEMOIR a8 oa ec a so se vahas. 6B oacee se ee This Tobacco Pio Is Built Like a Cornet, but Isn't RRRIMR ORR ee ie ee eye wus vo. Gund a Giareiens nag nee 847 Wall Hanger for the O:dinary Electric Lamp Stand 923 Inexpensive Aluminum Polish.................. 923 Constructing a Convenient Table for the Porch... 924 SR UNRNTNOTY MERMDOKADE 5.5555 cio 5s oo a arse once sane 925 sa nage Effectively Used in Library Chair and ons Qpen a oe Ba Eee eos aah eee 927 ing Attachments on Shoes to Aid the Swimmer. . 930 Fishline Float Made of an Ordinary Thread Spoo! 930 | Convenient Material for a Bait-Catching Net. 930 Banding a Tree Trunk to Catch an Destroy EOS eS oe ee ae en 931 Cleaning the Gilded Portion on Picture Frames... 931 ooling Camp Food by the Evaporation Method. 931 Rocking-Board See-saw for Children’s Playground 932 Deep-Sea Fishing with a Little Submarine......_ 857 Handless—And Yet a Champion Billiardist. 868 Practicing the Head-Hold with a Wooden-Headed DMEM IRURN RE Ss evi my ib ce, assis Gace 6 Vos 31s 4 waa GORE 879 | Railways that Run Under Water............... 890 s PPM DMER PURI OMNEN 252662915363 505 6 Sess Sos 2 esos kuied: Gissaiavakg re Rm 906 Giant Kite for the Crown Prince of Sunny Japan. 03 New Underwater Bicycle...................... 909 Cy eS | sa ee tae ee ae > 927 Wing Attachments on Shoes to Aid the Swimmer 930 Combination Camp Kitchen Cabinet and Table.. 934 MISCELLANY ; Old Tin Fruit Cans May Be Used Over Again..... 932 An Overhead Dove-Tail Suspension for Table || | Lighting Up East Indian... .0eeesa ee. 804 oT A Se ee eee 2) 1 oy, Pishabiy Escaped This How to Make a Pocket Plumb and Level in a Block 933 Sle! ‘Up’ .. : A _ — eee st bee tae ha levees: Making Camp Hammocks from Gunny Sacks. .... 933 | Shoes for Mud GE IGRI RRS Cement for Mending Valuable China Dishes... .. 933 Raising a Ghost to Prevent Waste of Commodities 806 Stakes with Guide Lines for Hoeing Garden Beds. . 934 | cca naccesexus aes vke ret 807 Combination Camp Kitchen Cabinet and Table . 934 | Hanging Flower-Gardens in Old Gas-Lamps...... 807 Simple Designs for Sheet Metal brapaene 5 F teeteeee 935 | Artificial Birds in the Flower Bed............... 825 Making a Lattice Trellis for Roses and Vines..... 938 low a Floral Urn Was Made from a Boulder.... 825 How to Make an Efficient Fireless Cooker........ 939 | Use this Detachable Handle to Protect Your Grip. 832 A Driver for Holding a Screw While gg It... 940 | Over Fifty Different Woods Are Sold as Mahogany 834 Extension Holder for Hauling Long Stock......... 940 | Giant Granite Ball T ells _ with Great Accuracy a A Rope Suspension Bridge for a Garden......... 941 | Red Cross Knitters and Sewers, Use a Cane..... 848 Startin: ng a Very Small Screw with Adhesive Tape.. 942 | A Soap Bubble Can be Made to Last for WMonths. ae Scaffold for Holding in Place with a Pole......... 942 Fold Up the Propeller Wien Vou Want tokow, sae Holding Photographic Plates from Tray Bottom.. 942 | This Isn’t the Only War With High Prices....... 863 A Convenient Summer Cottage. ....... ee on Pi 943 his Submarine Raises Money Instead of Killing. 865 How ad —_— e an Automobile Spring Leaf- He Outswims the Ducks in His New Diving Dress 869 ’ Separator... 20... 0.0.20. sence eee eee e ees 944 | The Service Stamp Is the Latest Patriotic Device = ql Self- + smelt Wheelbarrow for Aggregates. ..... 945 Worse Than Civil War Shinrlasters............. a oo arene Steves to Mako A Tiny Rival of the Wrist Watch... ............ 893 Wear... 2. ence eee eee eee ees 45 Knitting Is Not Confined to the Ladies.......... 893 Making a Photographic Timer Out of Watch. .... 945 Here Is That One-Hand Cigarette Case You Want pd Joining the Ends of Carpet Rags Without Sewing 945 Making Things Harder for the Forger of Checks. An Inexpensive and Effective Water Cooler...... 946 | What Makes the Rumble of Thunder?........... S Renewing a Worn Artist’s Brush by ens | It 946 Half Million Words in English Use.............. 903 A Spring Lock for the Cover of a Garbage Can. 946 | This Device Will Take Care a Your Street Thimble Used as a Ferrule on a Tool Handle...... 952 el eee eR ee te = A First Aid to the Singing- Teacher. ............. 908 RADIO COMMUNICATION Canned Ostrich Eggs we ee LEN w Ate weal 909 The Story of a Wireless Hero................... 828 | Looking Through Your Hand.................. 911 ome-Training for Wireless Heroes............. 910 | What the Twenty-Dollar Gold Piece Has Seen... 913 Wireless Work in Wartime..................... 957 A Band of Brigands Were the First ‘“Chauffeurs’”’.. 916 Mind Reading by Wireless..................... 959 | A Package Handle That Saves Your Time and Cord 917 } POPULAR SCIENCE MONTHLY is issued monthly. Yearly subscription in the United States $1.50. Canada, $2.00 i Foreign $2.50. SINGLE COPY, 15 cents. POPULAR SCIENCE MONTHLY may be had at all news sta tional News Company, Breams Bldg., Chancery Lane, Lon Forms close the twentieth of the second month prec Entered as second class matter at the New York Post Offic second class matter at Post Office Department, Canada. The contents of this Magazine are copyrigitted and President; R. C. Wilson, Vice-President; O. B. Capen, Sec MODERN PUBLISHING COMPANY, ndsin the United States and Canade; also from the Interna- don, E. C., and at Brentano's, 37 Avenue de 1’ Opéra. Paris. eding ster of publication. Advertising rates on application. e, under the Act of Congress of March 3, 1879. Entered as must not be reprinted without permission. H. J. Fisker, : retary and Treasurer. , 225 West Thirty-ninth St., New York City form Trai I ha stud adv. penc sion For ing ing I ai give Lh and amb you at h will sple: com thor und

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Popular Science Monthly 3 Your Future is in Electricity— Obey that ‘“‘Hunch.”’ Get a Move on Yourself —Here’s Your Chance— If You Act Quick I Will Give You Special Per- sonal Training at Home. OnlyaLimited Number of Students Can Secure Qualify at Home —With My Help STUDY BY MAIL My New Course and a Common School Edu- cation All You Need. Fit Yourself in Spare Time to Earn $45.00 to $175.00 a Week. SPECIAL Earn While You Learn My Special Instruction | Right After You Are Enrolled —ACT NOW. — I Will Give You _—— —— CHIEF ENGINEER in Quick Money-Making Elec- MY OFF ER TO YOU: Your Instructor trical Branch—FREE. If, you act quick I will accept you among a few more students to complete Home Study class now forming. Grasp this wonderful opportunity. Fit yourself by a few months’ facinating Home Training to bea REGULAR CERTIFICATED ELECTRICIAN. I have a splendidly attractive proposition for you. I GUARANTEE you satisfaction in the study of this great profession. Decide to enter it while you can do so on terms especially advantageous to you. Plan a glorious future. Secure for yourself the assured inde- pendence, the handsome income, the agreeable working conditions, the easy profes- sional hours and the unlimited opportunities of trained and experienced Electrician. FREE ELECTRICAL OUTFIT For the next 30 days [ am giving each student an Outfit of Electrical Test- ing Instruments, Tools, Electrical materials and Motor absolutely Free. My instruction is by practical methods and this outfit is used in work- ing out the lessons. Practical training with the theory makes perfect. I am Chief Engineer of the Chicago Engineering Works, and I can give you the training that will land the big jobs and hold them. I haven’t the space here to tell you all the advantages, benefits and privileges GUARANTEED to my students. If you are ambitious to make a big success in the greatest profession on earth—if you are ready to start right in and study Electricity the ‘‘easy”” way— at home—mail me the FREE “OUTFIT” coupon without delay. I will send you full particulars of my personal instruction plan, my splendid laboratory and educational facilities, my wonderfully complete and fascinating course of bed-rock lessons, and my thoroughly practical method of making Electricity easy to understand and master. Write me NOW. L. L. COOKE CHIEF ENGINEER Chicago Engineering Works Dept. 36,.441 Cass Street, CHICAGO, ILL. PEIOWY Niaavisssve 61:8 e040 Pda sl iayiee ras aceon STATE L. L. Cooke, CHIEF ENGINEER Dept. 36, 441 Cass St., Chicago, Illinois Without obligation on my part kindly send at once, fully prepaid, partic- ulars of your complete Prac- tical Home Study Course in Electricity. ee oe i When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly HAWKINS ELECTRICAL GUIDEs —{ = —— a —_— : MN \\ INS hk Hawk is) ‘HAWK Si aN F / | ied f 3 Het 5 . CURIE} LLFCTRICAL | rl cil crpycall LscvRICs LEerRical recTeval si Wh : Cunt) Gung 1 Ie | | ks a s , : AUIDE; (Que st yglt 4 RMUIDES iC “fh yo. | I Bigger P LECTRICITY When writing to Advertisers please mention Popular Science Monthly through hel; in C stan the- can Jus help you refe! tain whic theo way ject: infor quest famo ready $1 Yo if y com expe thro the : edge Elec Ow: neve gues tryit They finger The carry have cover:

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Popular Science Monthly 9 HAWKINS ELECTRICAL GUIDES are a necessity in_the daily work of every Elec- trician, Mechanic, Engineer and Electrical Student. The set contains ten wonderfully helpful and practical volumes—written in clear concise language—easy to under- stand—no wasted words—full of up-to- the-minute electrical knowledge which you can apply to the problems that come up. Just think how much these books will help you. In Hawkins Electrical Guides you always have at hand for immediate reference or study, a wonderful work con- taining 4,700 illustrations and 3,500 pages which cover all the subjects, principles, theories, practices, problems, troubles and ways of doing things electrically. All sub- jects are indexed so’ that you can find the information instantly. Written in the modern question and answer form. It’s like having a famous electrical authority always at your elbow ready to answer any question you ask. $1 A NUMBER-—$1 A MONTH You need specialized knowledge today if you are to master electrical forces and command the high salary of an electrical expert. Success in electricity will come through your ability to acquire and use the specialized knowledge of others—knowl- edge collected and condensed in Hawkins Electrical Guides. Owners of Hawkins Electrical Guides never ‘‘get stuck.”” They never have to guess. They never have to waste hours trying to “dope out”’ electrical problems. They have the information they need right at their fingers’ ends. 3,500 Pages—4,700 Pictures Pocket-size—Flexible Covers The Guides fit your pocket. You can carry a number about with you till vou have mastered its contents. Bound with flexible covers, gold title and edges, they are truly beautiful books. Well printed in large type on high grade paper they are a pleasure to study and possess. When writing to Advertisers please mention ?opular Science Morihly Do you want to know the facts about the following electrical subjects? They are all covered in Hawkins Electrical Guides. No. Contains 348 pages, 388 illustrations. Electrical signs and symbols—static and current electricity—primary cells—con- ductors and insulato resi and ductivity—magnetism—in-

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Rarer Popular Science Monthly 1 Man! Are YoulOO% Alive? R ARE you satisfied to drift along half dead—half alive—always getting on the nerves When writing to Advertisers please mention Popular Science Monthly of those with whom you associate — overlooking half of the beautiful things around you—afraid to acknowledge that you are in reality a physical wreck? Then you are indeed only 50% man, for which the world has little or no use. But perhaps you don’t know that you can be rebuilt —that you can ‘‘come back.”’ Then to you I say, confide in me and I will make you worthy of the deepest respect of your fellow man—worthy of the confidence and love of the best woman in all our land. Get the Joy of Strength and Health the man who admits he has physical defects has taken his first step toward manhood and honesty, but he must not stop there; he must see to it that he gets good competent advice and attention, and to do this he must go to the one who can prove by his own physical condition, that he is able to really give him that health, strength and physique he desires—go to a man who practices what he preaches—I am that man. I built my- self up first, I experimented with my own body, until I made myself what I am today, what those competent to judge say I am. ‘‘The living illustration of the perfection of the human form, according to the highest standard.’’ I don’t care a rap what has caused your present unfitness, how you have been brought to your run down physically unfit condition. I will rebuild you. I will make a man of you, not a 50% man, but a Man—a 100% man. _I accomplish all this in Nature’s own way. No drugging, no medicines, no fads of any kind. Simple scientific instructions added to the proper method of living, and I guarantee you that I will accomplish all I undertake and I won't undertake what I cannot accomplish. The Strongfort Course of Instructions will in no way interfere with your ——— or plans. You may follow your daily | calling no matter what that calling may be; even if you attend school or college my in- structions will not interfere with your studies in any way whatsoever. And what is more, you can follow to the letter, the Strongfort System in the privacy of your own home, without the knowledge of any one in it and without the aid of a Gymnasium. Now Be Honest With Yourself Get in line with the men worth while. Make work and living a pleasure, not a bore. Sit right down and write me fully. Confidentially, pour out your physical troubles to me and believe me I will tell you frankly just what you should do, just what I can do, so that you can honestly face the world as a man, so that when you see your little ones playing around your fireside, you can proudly feel that you did everything you possibly could, to bring them into the world physically perfect. Don’t ever forget all the world loves manly men; women look up to and truly love them—men admire them. Did you ever see a thin emaciated fellow—one who shakes hands with you as though his wrist were broken. Did you ever see such a man amount to anything? Now get busy—do not delay one single day. Remember by writing to me you in no way obligate yourself to accept my instructions, while on the other a — I bo yo gg fear- FREE CONSULTATION COUPON ess advice that will be many coun weoreh the few minutes i Mr. Lionel Strongfort, Newark, N. J.:—Please it took you to write me. send me your book *‘Promotion and Conservation Without another moment's of Health, Strength, and Mental Energy,’’ for hesitation cross the free con- postage of which I enclose 6 centsin stamps. } sultation coupon-herewith op- have marked (x) before the subject in which I am osite what _ a. be interested. e your main ailment, an mail with you name and ad- i : po ; Hh! olla 0. 498 dress written plainly there- : ‘Asthma .. Nervousness on. You will hear from me | Obesity ‘Poor Memory at once and you will hear Waadache Rheumatism something well worth while. 4 > oes a pee .. Rupture . .Gastritis : i ..Lumbago .._Heartweakness Get this Book | , ‘Neuritis : —— a >] .. Neuralgia ‘ n Disorders It Ss Free! .. Flat Chest . .Despondency ] .. Deformity (describe) ..Reund Shoulders If you will send mesix centsin _. Insomnia ..Lung Troubles ALPE eaisr sts stamps to cover mailing ex- } _Impotency .. Increased Height nses I will forward free my .Short Wind .. 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Popular Science Monthly ey MEN OF ALL AGES| HOUSANDS of men, hundreds of them advanced in years, have made successful fresh starts in life by placing themselves under the competent direction of the teaching staf of the N. Y. E. S. For years and years the very mention of the New York Electrical School Che NEW YORK ELECTRICAL NIG s(@le)e has meant without further explanation all that is best in trade training. For this reason the N. Y. E. S. stands alone in its world-wide fame as the only school that has made new men out of old. The N. Y. Electrical School is an institution wherein the manifold branches of Electrical Industry are taught through ACTUAL PRACTICE. And the only way to master a task is to do. it yourself and by doing it learn to do it perfectly. Necessarily man has also to learn the reason behind the various problems and processes, because the man of practice and no theory or the theoretical man without practice is only half a man from the point: of value to him- self or to an employer. A learner at the N. Y. E. S. does not have to finish within any stated period, as there is NO TIME LIMIT to the Course. At this School it costs no more to take one’s time, and men advanced in years need have no fear of being hurried by the younger and more nimble-minded. There are no ‘‘classes."" Every “‘learner’’ goes ahead as fast as he shows proficiency, and graduates just as soon as he has proved by what he has done that he knows how to do it! That's why this school—this actual-practice-electrical-workshop is in such high standing in the educational world. The New York Electrical School 40 West 17th St. NEW YORK OPEN ALL SUMMER WRITERS FREE BOOK! A WONDERFUL BOOK—READ ABOUT IT! Tells how easily Stories and Plays are conceived, written, perfected, sold. How many who don’t DREAM they can write, suddenly find it out. How the Scenario Kings and the Story Queens live and work. How bright men and women, without any special instruction, learn to their own amazement that their simplest Ideas may furnish brilliant plots for Plays and Stories. How your own Imagination may provide an endless gold mine of Ideas that will bring you Happy Success and handsome Cash Royalties. How new writers get their names into print. How to tell if you ARE a writer. How to develop your ‘‘story fancy,” weave clever word-pictures and unique, thrilling, realistic plots. How your friends may be your worst judges. How to avoid discouragement and the pit- falls of Failuree HOW TOWIN! This surprising bookis ABSOLUTELY FREE. No charge. No obliga- : tion. YOUR ‘copy is waiting for you. itt Write for it NOW. Just address WRITER’S SERVICE Dept. 34 Auburn, N.Y. When writing to Advertisers please mention Popular Science Monthly I can make a good penman of you at home during spare time. Write for my @ free book, ‘‘How = Become 2 Good enman.’ t con- tains specimens and Write tells how others mas- tered penmanship by the Tamblyn System. Your name will be ele- gantly written on a card if you enclose stamp to pay postage. F. W. Tambiyn, 437 Meyer Bldg., Kansas City, U.S. A, r Print Experts WAY EARN $25-$50 week. Interesting, My Fascinating and Influential Profession. Police Depts, Factories, Industries, Banks, Capitalists, Detectives, Gov- ernment Depts., identify with this system. Learn in Spare-Time Study at Home. FREE—Send for SAMPLE LESSON. Reduced Tuition Rates. SCHOOL OF FINGER PRINTING 600 Tremont St., Boston, Mass. co ITIONS DEMAN ELECTRICAL tiiedcverznoycunemes The Bliss Electrical School, with its well-equipped shops and laboratories, is peculiarly qual fied to give a condensed course in Electrica ENCINEERING with Mathematics, Steam and Gas Engines, Me chanical Drawing, Shop Work, and Theoretical and Practical Electricity. Students construct dynamos, install wiring and test electrical ma chinery, Course, with diploma, complete IN ONE YEAR For practical young men with limited time. 26th year opens Sept 25th. Catalogue on request. 102 Takoma Ave., Washington, D @ ques volu and 534 x ete., CcTOSS-

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Popular Science Monthly 13 ee ee oe ee es es ee ee | AMERICAN TECHNICAL SOCIETY, Dept. A-120-A, Chicago, U.S.A, f : Please send me a set of Automobile Engineering for 7 l ‘ days’ examination, shipping charges collect. lf I decide to buy, I will send $2.00 within 7 days and the balance at $2.00 a month until $17.80 has been paid. Then you will send me a receipt showing that the books and consulting a eo I membership are mine and fully paid for. If I think that I Will Bring You can get along without the books after the seven days’ | I trial, I will return them at your expense. | NAME. sessssseseseeeeeeceerecsseseerecssseseeeeescerees (These Books ee Pe [essence te eee eee eeeeeeeeeeeer eee eeet Cee eeeeeeserecs — a ee ee ee ee ee ee ee O those who fill in and mail the coupon immediately we will send a complete five-volume set of Auto- mobile Engineering (1918 EDITION) without a penny’s deposit. Examine them —study them—use them as if they were your own for an entire week. After- the x trial—if you think you can get along with- — out the books—return them at our expense. P 50c If you keep them, pay the spécially- me reduced price at the rate of only 50c a a Week week. But you must act now! The 1918 Edition rising cost of paper and binding materials ' won’t permit us to continue the present low price much longer. All About Auto Repairing No car owner, chauffeur, garage owner or repairman can afford to be without a set of Automobile Engineering. It is just off the press and answers fully 10,000 questions on the repairing of all types of pleasure and commercial cars. Two entire volumes are devoted to ignition, starting and lighting systems. Welding, vulcanizing and public garage equipment and operation are thoroughly covered. Five thick volumes, 534 x 814 inches, flexibly bound in genuine morocco, gold stamped. 2,500 pages; 2,100 illustrations, diagrams, etc., that make difficult points as simple as A-B-C. Written in plain, easily-understood English; carefully cross-indexed for quick reference. wat ne Books] Gend No Money! Cover Explosion Motors, Weld- e ? e e ee Mater Construction | Shipped for 7 Days’ E xamination and Repair, Carbureters Remember, you don’t have to send a penny. Just fill in and mail and Settings, Valves, | the coupon and the books will be shipped to you at once, express Cooling, Lubrication, | charges collect. If they fail to meet with your expectations, return Fly -Wheels, Clutch them at our expense. If you keep them, send $2.00 within seven days and $2.00 a month Transmission, Final thereafter until the rock-bottom introductory price of $17.80 has been paid. This is $7.20 Drive, Steering, Frames, less than the regular price of $25.00. Tires, Vulcanizing, Igni- 4 e ° tion, Starting and y C Iti g S FREE Lighting Systems, Wir- ear S Onsu nl ervice ing Diagrams, Shop Kinks, Commercial Ga- rage Design, Equip- With each set we give you, absolutely free, a year’s Consulting Membership. The regular price is $12.00, but you get it free with the : set. Put your perplexing problems up to a staff of automobile experts. ment and Operation, | Ask them as many motor questions as you wish for a whole year free! Electrics, Storage Bat- Your name and address on the coupon brings the five books to you, express collect, for teries, Care and Repair, seven days’ trial. This offer is open to every person within the boundaries of the U nited Motorcycles, Commercial States and Canada. Act quick—while the offer lasts. Send coupon today—NOW! Trucks, Glossary. | AMERICAN TECHNICAL SOCIETY chivistat&.. When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly EARNS BIG PROFITS _ It’s easy to make big money selling delicious, buttered popcorn and hot roasted peanuts in your spare time, evenings and holidays with this handsome, white enameled, Bartholomew Sanitary Popcorn and Peanut Machine. Start a money making business of your own. This attractive, sanitary machine draws the trade and makes money fast—in stores, on street corners, in theater or hotel lobbies, near picture shows, baseball parks, amusement resorts, etc. Thousands of men and women are coining money with sit. You can make money too—right in your own town, with this wonderful machine. Don't miss this opportunity to make money. Write for FREE BOOK which explains our low prices and easy payment plan. It fully describes our complete line of Bartholomew Popcorn Machines, Peanut Roasters and Vending Machines for store and street use. THE BARTHOLOMEW CoO., 501 Heights Street, Peoria, Illinois Stronger, Clearer i Weakness, huski- Liu _ ness and harshness ban- ‘ ished. Your voice given a wonderful strength, a wider range, an amazing clearness. This done by the Feuchtinger Method, endorsed by leading European musicians, actors and speakers. Use 2t in your own yme. Simple, silent exercises taken a few ———_ ct vigor =o ae: organs gi rpassing quali \e Send for the facts § ani proofs. — Do You Stammer? If you have any voice impediment this method will help you. You need not stam- mer or lisp—if you will follow our instructions. WRITE ‘nd the coupon and get our free book end literature, We will tell you just what this method is, how it is used and what it will do for you. No matter how hopeless — case may seem the Feucht- 4 nger method will improve our voice 300 per cent. lo oe on you if you ask for this informa- 4 free, postage prepaid. dust mail the coupon, 7 CO Singing Perfect Voice () Stammering () Lisping 8 institute 7 72 ameondu. 4 ES eee CHICAGO Perfect Voice Institute StudioA-120_ 1772 son Ave., Chicago y Send the book and tion. We gladly send it facts about the Feuchtinger 0 Pe aca Have put X a Voice ,for You! — When writing to Advertisers please mention Popular Science Monthly ELECTRICIANS WIRING MANUAL SENGSTOCK Electrician’s Wiring Manual By F. F. SENGSTOCK Electrical Inspector Chicago Board of Underwriters When you’re up against a stiff job, let this book be your helper. It will tell you exactly what to do and how to do it in strict accordance with the National Electrical Code. The book that thousands of Wiremen, Contractors and Electricians have _ been waiting for. Not a discussion on Code Rules, but straight talk from a man who knows the game from A to Z and gives you the benefit of his many years’ experience. Shows you how to proceed so that your work will pass the most exacting inspector. Every step explained in detail, made clear by 415 careful drawings. Twenty-seven Chapters, 410 Pages, 415 Illustrations of Sound Practical Informa- tion. Flexible Leather Binding. Pocket Size. Price $1.50 postpaid 800 copies of this book were sold before publication when announced as containing 22 Chapters, 240 Pages, 200 Illustrations. Since increased to 27 Chapters, 410 Pages, 415 Illustrations without raise in price. POPULAR SCIENCE MONTHLY 225 W. 39th Street New York City eee eR ne ee with 1 it is doub War,” has War Song impression Tipperary; Tommies cantons ng it som Have ect for ¢ valuable / our new GUIDE.” secure CO) KNICKE ——— Short hour: lifetime po: ME ernment. divisions. ify. SAT TER! Leal Becon of trail paying refunc catalog Garv witho Clas: Write trate

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RE ee ’ Who will write the INGUIKAT Yan un entering its aaaa year in the “World War” Ry tent if one which will be known as the ‘‘Hit of the it is ¢ has as yet made its appearance. While it, is true that such War, Songs as “Over There’’ and ‘‘Liberty Bell” have made some we ssion, have Our Boys adopted another ‘“‘It’s a Long Way To impee ry, +> which has been the great favorite with the ‘“ ‘English Tipperary; Inasmuch as_ several Commanders of our training pnd have requested boys in the service to write such a can it appears to be still wanting. * Have you an idea which you think might be used as the sub- for a Patriotic or War Song? If so, you may secure some luable fnformation and assistance by writing for a Free Copy of po new booklet entitled “SONG WRITERS’ MANUAL AND GUIDE.” We revise song- —— omnes and poienn of — C and facilitate free publication or outright sale. eecure copyright Poems submitted examined FRE KNICKERBOCKER STUDIOS gg GAIETY BLoe., N. Y. C. Short hours. Easy work. No strikes, Nohara times. Steady, lifetime positions, "S75 to $150 a month to start. Quick promotion, i - ° ’, lf you are an American ce 18 or fi over write for FREE book that tells about these and many other wonder- On 3 anaes oneres by U- = Gox- it tom House, Panama Canal and othe’ Picco jon Mail, Post Of Ciel Service pocretary: pereroiner: You can ualify. Write Pf or FREE BOOK and ty cial 20 Day Off quilty Wale (vn SERVICE SCHOOL, 166 News Bldg. Rochester, N. Y. BOOKKEEPING IN 30 DAYS Learn at Home. Earn Bi iq Money. Become an expert through amazing New Method of training. Nothing like it. Hundreds successful in big paying pers. Easy to learn. Guaranteed. Money refunded if you fail. Write at once for Free illustrated catalog, Letters of proof ~ Special Offer. Address Garvin ncaa 75-735 woopwand ave, Detroit, Mich. TEACH eH) 177 VLU: BY MAIL ar World’s First Prize for best course in Pen- —* Under my guidance you can become an expert Amplacin: ym A rad any students as instructors in commer- Pil coll colleges at h aoe u wish to become a better ——. write me, I will Feat an REE one of my Favorite Pens and a copy of the erian Journal. Write me today. ‘Address C.W. RANSOM, 340 Essex Bidg., Kansas City, Mo. Comics, cartoons, commer- Be OKY cial, newspaper and magazine 4 illustrating. Pastel crayon z portraits and Fashions. Earn $25 to $200 a week. By our simple method your talent is quickly developed without interfering with present work. By Mail or Local Classes. The largest practical art School in the world. Write for full particulars and list of successful pupils, illus- trated prospectus, etc. Endorsed by newspapers and magazines. ASSOCIATED ART STUDIOS, 58D, Flatiron Building, New York, N. Y Electrical Meter Engineering *‘The Profession With a Future’”’ Now learned athome. Big demand tor compe- mt men. Pleasant, interesting, fascinating employ- ment all the year "round, with exceptional opportu- nities for advancement. Success guaranteed. High salaries offered. No experience necessary. ins Special Offer ! In order to ain for apo sitions, we are ioking a great s Sial offer to a limited number Write to ay for full particulars—FREE. No obligations. Bea Meter Engineer, the man who fires; not the one whois fired. Be boss. Write today. Fest sere Correspondence School Dept ort Wayne, Indiana Popular Science Monthly When writing to Advertisers please mention Popular Science Monthly “Look At Him Today!” "Six years ago he started in here just as you are doing. Now he’s General Manager and makes more in a day than he used to make in a week. ‘The first week he was here he began to train for the job ahead by studying in spare time with the International Correspondence Schools. Inside of six months he got his first promotion. 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MERICAN SCHOOL | OF CORRESPONDENCE 5 DEPT. G-120-A CHICAGO, U.S. A. SOOOc 5 COOCG ———— = 3OO0OC ) Write on margin below your name, home address, and posi- | tion for which you desire to qualify. Tear off, mail today. IOC > « 3C 20O00C > 7

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me F 2 oe earn Electricity EARN SI00TO $400 PER MONTH In the electrical business, thou- sands of skilled electricians needed in Government service and at home. The need is growing greater every day and enormous salaries are paid. Right now is your big oppor- tunity. Come to COYNE and let ex- perts train you in our $93,000.00 shops. Train you to be a master Electrician. We assist you to a position after graduating. We have more positions than we can COYNE TRADE AND ENGINEERING SCHOOLS ‘each hort Time at Small Expense. Start right now— a wen Pa three to four months. Students live in comfortable homes in most beautiful part of city—on the Lake. Manystudents earn large part of their living expenses by working a little in their spare ‘aan Our employment dep’t furnishes these positions without charge. | ‘SPECIAL 8S WEEKS COURSE FOR DRAFTED MEN Drafted men, you will soon be called into service. Uncle Sam needs tens of Beusnde of ah tullod I” snot wil ba piven an Sopastcity ese ii me i Plumbing, and Sanitation. if fo i ou take no chances. We give th u 4 ‘ou are sent to Pont before you finish. But you'll have to act quickly for we can only take Timed AF TING—PLUMBING—MOTION PICTURE OPERATING t thoroughly, quickly and practically by masters right in our big shops— big demand for our graduates— we have more positions than we can fill. WRITE NOW en nee for on ie eure and mention the trade You are Bennett Wellington Cooke, Dir., Coyne Trade and Engineering Schools, 2 . Hlinois St. Te Chicago, Hl. New Book Free Write today for the book that tells about the opportunities im the profession of Signal Engi- neering. Men are needed. Learn, too, how you can get the training that you need to fill the big job. $125 to $300 a Month The free book will give you just the information you want. Write for it now— immediately. Here is @ golden %pportunity. Dept. of Signaling ReverewooaSta.. Cnicsge, tb, Music Lessons Book Wonderful home-study music lessons un- Sent der great American and European teachere given by the University Extension Meth- od. The lessons are a marvel of simplicity and completeness. Any- one can learn at home. Endorsed by Paderewski and many other great authorities. s ._ Any Instrument or Voice Write, telling us the course you are interested in, age, how long have taken lessons, if at all, ete., and we will send you our Free containing text and illustrations covering Lessons in PIANO students’ or teachers’ courses) by the great Wm. H. Sherwood, HAR- ONY by Dr. Protheroe and Rosenbecker, VOICE COURSE (with aid of Phonograph by Crampton PUBLIC SCHOOL MUSIC by Frances E. N, CORNET, MANDOLIN, GUITAR, BANJO, REED ORGAN, b ually eminent teachers. Send Ow for Fee Book and learn how easily you can | become a fine singer, or a skillful player. ' Write today for full particulars. Investigate without cost or obligation. ' Popular Science Monthly Consulting Accountant Financial Adviser ’ Better your position in business. The La Salle Home Study Course. in Higher Accountancy will prepare you in a new profession of splendid op- portunities. rth Thereareonly 2000 Certified Public Accountantsin America. Yet there are overhalf a million firms tl_at require the services of these expert business analysts. The field is truly unlimited; thedemand always greater than the supply of proficient men. That shows where oppoeay is. rite for information about the Course in Higher Accounting given by LaSalle Extension University. ; Learn By Mail With our training you can readily qualify for the position of Auditor, Certified Public Accountant, Comptroller, etc. Many expert accountants earn $3,000 to $10,000 annually. Small Cost—Easy Terms Our course and service is under the supervision of a large staff of C. P. A.’s, including William B. Castenholz, A. M., C. P. 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The LaSalle Guarantee We will give you a written guarantee that should you fail to pasa the Certified Public Accountant’s examination held in any state, we will give you special instruction and help—without additional charge until you do pass. We further agree to refund entire amount of tuition, ac- cording to our Guarantee Bond if dissatisfied upon completion of course. Our free book tells the whole story. Explains state examinations and regulations, salaries paid expert accountants, ete.—also gives com- pote information regarding the Course and Consulting service. Take he first step toward greater success by mailing the coupon today—NOW. ——= = FREE BOOK COUPON === LASALLE EXTENSION UNIVERSITY “The World’s Greatest Extension University’’ Dept. 683-H Chicago, Illinois Send at once, without cost or obligation to me, your valuable book of accounting facts and full details of your course in Higher Account- ancy. University Extension Conservatory 3996 Siegel-Myers Bldg., Chicago When writing to Advertisers please Address........0+ ecccccccecccecccccccs mention Popular Science Monthly

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Popular Science M inal 91 Ruby and phire Jewels— Adjusted to the seg. SMASH ES) q Ga g ture— g oo to isochron. q Adjusted topositiong-s G 95-year gold strata case — Gg Genuine Montgom Railroad Dial— gq New Ideas in Thig Cases, Our 2iJewel | Look! | ‘Adjusted to tempera. PRR oe A Month a) And all of this for $2. 50—only $2.50 per month—a great reduction in watch prices eT in —direct to you—positively the exact prices ¢ ai a a the wholesale dealer would have to pay. Think of I? ;,F the high-grade, guaranteed watch we offer here at 1 ‘N such a remarkable price. And, if you wish, you may pay N this price at the rate of $2.50 a month. Indeed, the days of exhorbitant watch prices have passed, ; You don't pay sg See it First 23° =~ "Ole body until you - see the watch. You don’t buy a Burlington 7 Watch without seeing it. Look at the splendid A / beauty of the watch itself. Thin model, handsomely y7 shaped—aristocratic in every line. Then look at the = yy works! There you will see the masterpiece * the watch ———— makers’ skill, A perfect timepiece adjusted to positions, temperature and isochronism, @eeiatimivewey Every fighting vessel in the U.S. Navy has the Burlington Watch aboard. Many have over 100 Burlingtons—a few over 200. This includes every torpedo boat— Burlington Watch Co.” . every submarine as well as the big Dreadnaughts. 19th St. and Marshall Bivd. Dept. A120 Chicago, M Please send me (without obligation “N and prepaid) your free book on watches with full explanation of your cash 7. $2.50 a month offer on the Burlington ‘. Watch. e, Get the Burlington Watch Book by sending this as ed a a coupon now. You will know a lot more about watch buying @ when you read it. You will be able to “steer clear” of ¢ the over-priced watches which are no betters Send the a 4 coupon today for the watch book and our offer. *% Burlington Watch Co. When writing to Advertisers please mention Popular Science Monthly Sa het) Sa eh apt aie the eae a X\ 19th St. & Marshall Blvd., Dept. A120 Chicago, Ii.

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RATE 2 CENTS A WORD. Remittance in the form of currency, check, money order or stamps * MUST ACCOMPANY THE COPY. The July issue will close May 20th. el ACCESSORIES AUTO Specials: Ward Leonard Genera- CYLINDER Grinding. Quality, price and AUTOMOBILES _ —_ — pid and Davie Hicctrie ~~ parviee. ao oo uct — ing - a , | lamps mmers ‘ord engine air | clusively in a single e. ew oversize sone eon, aves gasoline, saves Te magnets, 4 all fit 3.00, Bosch ene and individually cast rings properly consume sear sell. Money back mane 6 cylinder, $10.00. Auto than will give your motor more power 4 cylinder, water ‘cooled, $30.00,, | when new. “The grinding that puts the guarantee, ‘Pica ars. Fords do 3 pte Buick ip Uti Mitchell, —— Hu pp 20, panch in We motor.” Write for prices to gallon. tion f for energetic and responsible Continental ‘and Buda Motors. sizes ving mak year, bore and number o tive propos ue advertising. Agents’ | 9nd types. Guaranteed. Mvrite or ‘an i= ers. You won't regret it. Bridgeport agents, oe " olesaling and retailing, | Bargain Bulletin No. 85. Johnston, West | Piston Ring Co., Third St., Bridgeport, rite for free literature. Friestedt Manu- End, Pittsburgh, Pa. : Conn. J facturing Company, 2033 W. Lake St. | “TT CaNIZING Auto Tires is a growing Chicago, illinois. . . . busin ese. Our plants are enay to learn to FORD ACCESSORIES . ickly apply our trans’er | operate ‘atalo free. You save ] nAyONe Gublems on automobiles, etc. | Tnstruction book on vulcanizing 75¢. Equip- FORD. Cana Burn Half Coal Oil, or Cheap- ofit. Samples free. Globe | ment Co., 302 Eighth St., Cincinnati, Ohio. | ¢st Gasoline, using our 1918 Carburetor; Enormous Jersey City, N. J. 34 miles per galion guaranteed. Easy start- Decalcomanie, : SLEEP in your Ford in MeMillin ‘Auto | {g- Great power increase. Attach it your- “INVENTIONS developed. Expert ad- Bed, $10.00. i. mall cars $12 Free | Self. Big profit selling for us. 30 days trial. vice, drawings, calculations, experimental booklet on auto ca: A. ing. Auto eet Com- Money back Guarantee. Styles to fit any and model work. Automotive Engineering any, De Sy 3, Bellin ham, Washingto automobile. Air-Friction Carburetor Com- Company, Castle Hall Building, Indianapo- | DADY, U°eDt- ng pany, 500 Madison Street, Dayton, Ohio. yo LIFE, “The National Gaso- | Popular Science Monthly, SUNLIGHT for Fords, Bright light all ' une Saver" rida motor cf-carbon. Increases, New York City. profits. "Sunlight System "Co. 1502-5 4 sreeeoline” or ng oe “Used all Gentlemen: sen 2 Ah : i jles, Trucks and “ractors. ° 5 d One do ey prepaid to you vroves our Since we have been using your WELDING ; claim. Send today. Arehart Chemical Co., . . , 1. Dept, 4, Rosholt, South Dakota. magazine to advertise our service, WELDING Plants, $25.00 to $300.00. the results obtained far exceed our | Designed for all purposes. Small cash pay- ¥ GET. the Power! “Carbonal’’ Kitis Car- ment, balance three to six months. Every ; bon, Saves Gasoling, increases yy a expectations. mechanic of sh shop shoud Be have one. Bermo 4 i ne, Saves : ar engh " | Bi Bog te alte ieuy. “pack ‘if not All of our advertisements placed Omak ‘ gatisfied. Agents making good. Carbonal | + about twenty-five national class BOATS AND LAUNCHES Be Products Company, Ruston, Louisiana. 'y-f WE WRITE Business-Building Letters | ud trade magazines are keyed | ~ DARROW'S Steel Bats. Finished parts ertise: , Circulars and Booklets, or patterns. Catalogue, 78 models. . iy se marnetive rates. Results guaranteed. and an accurate record kept of Darrow, 604 Erie St., Albion, Mich. t4 What is Your problem? Criterion Service, | vesulis. Our records show the Dep't. 1, West New York, New Jersey. LEARN Yacht Designing. Album 51 cost per inquiry from Popular | Yacht Designs, 25c. Yacht Model Em- i NVERT your bicycle into a motor- : A We eyele at small cont by using Shaw Motor At- Science Monthly is exceptionally | Potum. Liverpool, N. Y. tachmea' Ww ° 0.,° Dept, 180, Galesburg, Kansas. low and they are from readers DUPLICATING DEVICES DIMMERS, Williams’ dimmer quickly | Of high intelligence. The sales attached to any nts qaumple, emcient nce | average is higher than any other | Getter. $1 up, 50 to 75 copies trom pen. Bet, $2.00. neil, type-writer; no glue or gelatine Mfg. Co., 2183H, Railway Exchange, St. ublication used. Re 30 days’ Trial. You Louis, Mo. b need one. Booklet Free. J. V. Durkin & EN EASE a we aR “MODERN” _Duplicator—a Business jdd bey oee BATTERY . Charging pays big profits. Yours very truly, Reeves Company, Pittsburgh, Pa. City currents or gas engine operates. Easy UADRI COMPANY. terms. Hoherts, Troy, Ohio. Q MANUFACTURING POWER increased; carbon eliminated; TIRES—Double Tread Guaranteed for results guaranteed. our offer on page | g00d service. Absolutely Puncture-Proof. CLEVELAND Specialty & Mfg. Co., 126. 45 Automobile ead our ‘Company, Big Strons—Extra, heavy 30x3 tire, $5.25; pone gape Hg = rT make * sibdel, Baltimore, Maryland. 30x3%, $6. 33x4, $9.25; 4x4,' §$ "50: met: articles to order. '00) Aodels, : 36x4%, $12. oo: 37x5, $13. Big saving on | Stampings. Inventions develo fae ating Tee ann uncture | other sizes and tubes a Trade in your - x34, $6.60; | old tires. Discount to dealers, 10% de. | INVENTORS: Write Fisher Mfg. Co., are ‘$8.80: sand. "55. oo. Seg. 3° 90; 36x44, posts required on C, O. D. orders. Send | 2183D, Railway Exchange, St. Louis, Mo. $11; '36x5, $12.16; 37x6, $12.10. Non-skid, or list now! State size and bead of tire. | Patents & Patent Attorneys. 1 extra. 16% hen on C.0.D: | Max-Liben & Co., 205P West 48th Street, State if Q.D. straight-bead or | New York. a type. Specee Gisoouns to ——. Pri TRADE SCHOCES 10 $f a fu ne of new tires a TIRES At Wholesate—Send For ices agg I. Jaffess, 1319 D 5th Avenue, | on guaranteed tires and tubes. Lowest Pi Pe gy to Decorating, Seen Ty Branch—241 W. 54th Street. prices on earth. Overton Tire Co., Box P, . . Pa nting, by practical training. Oelwein, Iowa. logue. Chicago Painting School, 131 ‘North Wells Street, Chicago. teal and etleieas Wee hae sirens or illustrations = ; GAS-SOL” gives you 15 to 40% more Avente Oe LAiig MmPbell Iron Co., Cass | mieage and eliminates carbon, Money back HILES’ Watchmakinge and Engraving Guarantee. 100 tablets treat one hundred PATENTS—For automobiles are in great | gallons gasoline. Price One Dollar. Live og Oe races a and Be hon cn ee demand. We have special Automobile ae. — Gas-Sol, Dept. B, Wake- Francisco, Cal. tah ich amauta "yea | a | of trade r or \ j aoe Fee Victor J of Patent Buyers, \ ee son gee ge tated it | GRANDFATHER’S CLOCKS ; ree. r Z. vans * 8 Buildin, ness for the Progressive : Ninth, Washington, npiiaadixediies Advertisers of America.” A little story of GRANDFATHER’S Clock Works $5. a8. ; Results, told by the advertisers themselves— | Build your own cases from our free instru IF You want to ~— aaeihian, sell some- not the ublisher. You will be interested in | tions. Everybody wants a hall clock. You thing, or — e as write for my eading the little booklet we have prepared, a | can make = — building artistic clocks proposition, people are watching cory ue which will be gladly sent upon | for your frien We replace worn-out ese coins” ong thoneh for the very | request. It may solve YOUR problem. | works in old docks with works having chimes fing you have to offer. Let me tell you} D. W. Coutlee, Classified Department, | at money saving prices. Write for folder ll ‘“ Teach them. D. W. Coutlee, 225 Popular Science Monthly, 225 West Thirty- | describing the most beautiful hall clock ever est 39th Street, New York City. ninth Street, New York. sold at $25.00. Clock Co., Nicetown, Pa. When writing to Advertisers please mention Popular Science Monthly 19 ene > arate

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20 MOTORCYCLES, BICYCLES AND SUPPLIES MOTORCYCLE Bargains. Motorcycles at the old prices. Buy now and save $25.00, Don't wait. Hendersons, Harleys, Indians, Excelsiors, Emblems, P es, Thors, $50 to $100. ‘All makes corned — ready to ride. Motorcycle tires $3; auto bile tires $3; bicycle tires $1. Bicycles ‘$10 or tandems $20. Bicycles and motorcycles at at Lactory prices, old motorcycles, bicycles, machines taken in trade. Swap in yours. Highest prices allowed for them. d for catalogue. 7. a the Price Cutter, Rochester, New York WANT to sell Ay motorcycle of yours? I have a method t has-sold Write today for details; a ann willdo. D. W. =— 225 West 39th Street, New York CONVERT your bicycle into a motorcycle at small cost by using Shaw Motor Attach- ment. Mfg. Co., Gatalog tree, Shaw Dept. 68, Galesburg, Kansas. MOTORCYCLES—$40 and up. anteed rebuilt Harley-Davidsons, Ex Indians, etc. Every machine in sing order and all equipped with good e also have several used Sex Write today for i i Bi ws, 518 Broad Street, Guar- @ g> 70 5 N ewark, IF you want to succeed—if you want to get ahead in the world, you must read. Are you interested in electri automobiles, gas engines, aeroplanes, metal work, drawing, si chemistry or any mechanical ject? Write for the new Book Catalogue of the Popular Science Monthly. It de- scribes the and — lest and most easy to understand books o 1 these subjects. It is free. Popular Science Monthly, 225 West 39th Street, New York. get ogg hg $15 ele rebuilt and terms. Send 4 cents postage tor Bulletin “RR.” Peerless Mator- eycle Co., Watertown, Mass. LARGE stock of rebuilt motorcycles, new for all makes 20% discount; second- as new, 50% parts, good discount. ee ala Parts Mfg. Co., Chicago, BARGAINS—Néw and slightly used motorcycles, motorwheels, cyclemotors, talk- ing —- Edward Ryan, Poughkeepsie, BARGAINS in used Harley, Excelsior, for terms and Merkle, 162 North Cine Avenue, Roches- ter, New York, and 1616 Third Avenue, Birmingham, Alabama. BICYCLES. owes eg tA in 23 models and colors. gt tg gS oe a soonmmortes, equipmen $1.95 to $4.00. World Cycle Company, yt Gateway Station, Kansas City, Mo. Bo agg Se Advertising—How . B ess for the Pr A A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in reading the little booklet we have prepared, a copy of which will be gladly sent upon re- quest. It ma o—_— YOUR problem. D. W. Coutlee soe a Science Monthly, 328 fest Thirty-ninth Street, New York. MOTORCYCLES all makes $25.00 up. New bicycles at big reduction, second hand .00 up, motor attachements, motors, Cyclometors, $20.00 up. New hand parts ¢ as new 50% = ing, motors overhauled $10.00 up. — motors our specialty. Write for big bargain bulletin. American Motor Cycle Co., Chicago. Popular Science Monthly AVIATION AIRPLANE INSTRUCTION. Get out fo the rut. Enter a profession that offers you the biggest future. Our course in practi- tions open Men prepared for service the Signal oe . S. Army. and evening classes. Write for booklet “S’’ U. 8. Aero, 38 Park Row, New York City. MEN—Learn Flying, Aeroplane Building or Motor work. Government or exhibition. Winter and Summer field. Aviation Instructors, Pablo Beach, Jackson- ville, Florida, or Chicago, Illinois. WORLD-ROMIC System, Masterkey to all languages. Six textbooks, $1.44. French chart, 37c; Spanish, 37c. Aviation diction- ary, $1.50. anguages, 143 West 47th St., New York. PATENTS wanted in Aeronautics. U.S. Government spending millions in this class for Army and Navy. Our Aeronautic De- partment will give full information on this subject upon inquiry. Write for What to nvent, sent free. Victor J. Evans & Co., 79 Ninth, Washington, D. C. THE AMERICAN School of Aviation announces a new correspondence course in Mechanics of Aviation. A thorough training in Practical Aeronautics. American School of Aviation, Dept. 7596, 431 So. Dearborn Street, Chicago. FOR ADVERTISERS WE WRITE Business-Building Letters, Advertisements, Circulars gt — klets, at attractive rates. Results ‘anteed. What is Your Problem? Criterion § Service, Dep't. 1, West New York, New Jersey. SPECIAL! Inch display advertisement 100 magazines, thrice, $8.00. Universal Syndicate, Atlantic City. TWENTY Word Advertisement in 100 monthlies for $1.00. Thrice $2.00. Ameri- can System, Hollywood, California. FOR OFFICE AND FACTORY TIME Clocks—Cincinnati Clocks, No. 5’s Costkeepers. International and Bundy— Simplex button and card machines. Key recorders and autographs. Dial Comte. The biggest second-hand place in the U. with branches in seventeen large cities. Gousuit am ee telephone directory or write the Second TELEGRAPHY Write—Moler - TELEGRAPHY—Both M less; Station Agency, taught ‘quickie. Wire. mendous Demand—greater than un Permanent Positions ee Ideal Working Conditions. Great Op: pomp 9 for Advancement. Ww Dor- tors also neede All ex earn living while attending “¢ Oly oe largest school—established 44 years. {rt dorsed by Railway, Western Union and M coni officials. Now offering special ar months’ Radio course for young men sub to draft, enabling them to enter S eet —‘Preferred Service.” Large lustras may free. Correspondence courses algo = today. Enroll Immediately. Dodges bh omy 16th St., Valparaiso, India) " —.., TYPEWRITERS AND SUPPLIES LARGEST stock of Ty America. Underwoods, leon te a manufacturer’s prices. Rented ge applying rent on purchase pri trial. Instalment 7 if desiree pad ee ea on 3a writer Em- orium sta 8 ef treec, Chicago. Illinois. West Lake erry ya Y be PP Se ee GOOD Serviceable Typewriters =. Post card brings list. ree = ribbons, any standard machine aon Hub Typewriter Co., 286 Devonshire St., on NEW, rebuilt and slightly used Type. Ly; writers $8 up. Portable yachines $10” Ln Write for our Catalog 25V__ Beran writer Co., 58 W. Washington St., Chicago, UNDERWOODS, Olivers. Royals, Rem. ingtons, $15 to $45; rebuilt; Frarantecs free = ll, Typewriter Co., 193 N. Dearborn, COLLECTIONS AND ADJUSTMENTS COLLECTIONS everywhere. Prompt ness our watchword. Phoenix Mercantile Bureau, Omaha, Nebraska. DEBTS collected quickly! Established 25 years. William H. Dodd, 87 Nase St., New York. MODELS AND MODEL SUPPLIES We carry a complete line of brass gear and model supplies. Send for catalogue The Pierce Model Works, 3495 Pierce Ave, Chicago, Ill. WANTED—New Ideas. Write for list of Patent Buyers and Inventors Wanted $1,000,000 in prizes offered for inventions, Our Four Books sent free 176 Ninth. “Wash Department of The Cincinnati Time | Victor J. Evaas & Co., Recorder Co., Cincinnati, Ohio. ington, D. C. INVENTORS: For perfect models and DEALERS Get Our Sam moles and Prices. Walter Bogue Pen Co., 152 Cleveland, Ohio. ADDING MACHINES SAVES Time, Money, Labor—costs less than the average mistake. The Ray adds with speed and accuracy of highest priced machines. Used by U. 8S. Government, In- ternational Harvester Co., B. & O. Ry., business and professional men everywhere. Complete for $25. Send no money, but write for 20 day free trial. Ray Company, 2185 Candler Bidg., New York. LETTER SPECIALISTS SALES Letters, literature, stories ms, speeches, toasts, etc., written to order by literary experts. Rates reason- Eastern Educational Bureau, New Elmwood Ave., ae advertising WE WRITE Business-Building Letters, Advertisements, Circulars and Booklets, at attractive rates. Results guaranteed. What is Your Problem? Criterion Service, Dep't. 1, West New York, New Jersey. INCORPORATIONS THE Boy Electrician contains practical plans for Electrical Apparatus for work and play with an explanation of the gag eae of every day og Tells of the actual lences of a boy who gained a practical education in electricity by making his own Static Machines, Electromagnets, Cells and Batteries, ding Posts, Switches and Cut- Measuring Instruments, Induction Transformers, Motors, ynamos 394 Pages, 350 k Depart- 225 outs. Co! Wireless Telephone, etc. flustrations. Price $2.00. Boo ment. Popular Science Monthly, West 39th Street, New York. INCORPORATE in Arizona, Delaware, South Dakota or any State. Service guaran- teed. Literature on request. The Corpora- tion Service Company, Trinity Building, 111 Broadway. New York. dies at low prices, write Fisher Mfg. Co, 2183E, Railway Exchange, St. Louis, Mo, MOTORS, ENGINES AND MACHINERY WESTINGHOUSE, Wagner, Fort Wayne, Holtzer-Cabot, Emerson, Crocker Wheeler General Electric rebuilt ‘motors guaran’ for one year. Alternating and direct current, All sizes from 1-30 horsepower upwards. Tell us your needs. Satisfaction guaranteed or money refunded. Sned for illustrated price list mpeg and motors. Hyre Elee tric Co.,629 GH South CL earborn St.,( hicago. SMALL Motors and Generators: H.P. A.C. Motors $17.50— %H.P. $35: Battery Charging Sets: 100 new machines just received $30.00 each. Charging Light ing and Moving Picture Arc Genera $10.00 each and up. A.C. Motors 1 and phase up to 5 H.P. for immediate delivery. All material guaranteed new, less pee. Write for new bulletin. Johnston, Vest End, Pittsburgh, Pa. A BARGAIN, New Robbins & we Motors. 1—10 H. P., 110 Volt, Ne Universal. Nota toy, $9.00 eac! day-‘ill Elec. Co., Pittsburgh, ea. 500 TAT Electric Motors—110 Volts $16. leaners— AC—X-H.P Everything Brand br Irons—etc. pave pe ayes _ [Feet ee yo = ci sower than Man Send for Money Saving List. a ply Co., Ephrata, Pennsylvania. I WANT to send you ful pulling power of the Classified Columns of this magazine. If you want to buy some- thing, sell something, or exchange eomeching, te ay for full owt oe aay Coutlee, Manager Classified , A RG roof of the wonder- Popular Science Monthly, 225 West 39th Street, New York. When writing to Advertisers please mention Popular Science Monthly SMALL Power Gas Engine, to_run all kinds of small Machinery, Pumps, Washing Machines, Cream Separators, ete. Combine tion Counter Shaft and Starter. - arenes and cooling. age atisfaction guaranteed or mo’ Circular free. Universal Gas Motor 00. 364 Monadnock Block, Chicago. RN LES ai

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aan R ORO A

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rt for $2.00. Ross H. Kelly, 342 Batavia, Toledo, Ohio. AT fhe Beautiful Lithography for ,000 satpecneende, I oa = Statements <aydee Estos 772 Teutonia, Milwau- kee.

SERVICEABLE Pre-Used Printing Presses, Type, Supplies. Lowest _ prices, List for stamp. P.S. Bargains, Richland, Pennsylvania. - Letterheads or Envelopes, 50c. pre- d. Printer-Laborde, Mansura, Louisiana. p16. ““MULTIGRAPHING, Mimeographing, eran writing, Office Services, Business Ser- vio e Corporation, Washington, D. C. 200 Bond Letterheads, Prepaid, $1. South- western, 1413-B Berendo, Los Angeles 1000 Letterheads, $2.50; 5900, 310. Cop- per Journal, Hancock, Michigan ELECTRICAL

INVENT Something. Your ideas may bring wealth. Send postal for Free book. Tells what to invent and how to obtain a tent through our credit system. Talbert er rater 4675 Talbert Building, Washing-

eo catalog, just issued. Electrical tape and motors, wire, switches loom, a rosettes, lamps, fuses, sockets. na for r free copy today. Hyre Electric Co., 629. WN South Dearborn St., Chicago. Popular Science Monthly CAMERAS,PHOTOGRAPHY,SUPPLIES MOTION PICTURES

Prints FILMS Developed, 10c, all sizes. 4c We give 2%x3M%, 3c; 44%x4X, Profit Sharing Coupons. 24 hour service, work guaranteed. ‘Send negative for sam- ples. Girard’s Com. Photo Shop, 316 High St., Mills Alderman Bldg., Holyoke, Mass.

AMATEUR Photographer’s Weekly—the Journal That Teaches How. Special—3 ss mths (13 issues) for 25c stamps or coin. Established 1912. 403 Caxton Building, Cleveland, Ohio. FREE To Writers—a wonderful little book of money-maxing hints, suggestions, ideas; the A B CU of successiul story and play- writing. Absolutely Free. Just address: Writer’s Service, Dept. 6, Auburn, N. Y. WRITE Photoplays: $50 each. Ex- perience unnecessary; details free to be- ginners. Producers’ League 194, St. Louis. FREE Literature on “How to Write Moving Picture Plays.” Hursh, 123-K South Third, Harrisburg, Pennsylvania.

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HUNDREDS of berasine in slightly Lay Graflex Kodaks, Cameras and om Equal to new; Fully Guaranteed; 25% 60% saving. We sell on 10 day free ist, You take no chances. 18 yearsin business. Send for Our Free Bargain Book and Catalog. Central Camera Co. Dept. 55-A, 124 So. Wabash Ave., Chicago. INVENTIONS—Wanted in Motion Pic- tures and Photography. Special Depart- ment for these classes of invention. Advice, What to Invent and List of Patent Buyers sent free. Victor J. Evans & Co., 173 Ninth, Wasnington, D. C. BEST developing, printing in country, Send 3c for circulars or 15c and roll for sample developing, printing. Rare bar- gains used cameras. Ailes P. Greenwood, Melrose, Massachusetts. Clean Neat Finishing. Postage = both ways. Mailing boxes furnished. Get prices and samples. C. Grant Myers, Department One, Summit, New Jersey.

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LET Me set your poem to music. I wrote Missouri Waltz Song, Chauncey Olcott’s Lullaby and 100 other a bigs for proposition and list of my song R. Shannon, Room 602, Elisworth Butldine, Chicago. WHO will write the Song Hit of the War? If you have an idea suitable for such a song write for Free Booklet ‘‘Songwriters Manual & Guide. We rev poems, compose music, secure copyright and facilitate free publication or sale. Poems submitted, examined free. Son te Cae Studios, 168 Gaiety Bidg., New York City POEMS Wanted. Cash pala for songs. Submit MSS. to Needham Music Co., D183, St. Louis, Mo.

FOR BOYS

THE Boy Electrician contains practical plans for Electrical Apparatus for work and play with an explanation of the principles of every day electricity. Tells of the actual experiences of a boy who gained a practical education in electricity by making his own Static Machines, Electromagnets, Cells and Batteries, Binding Posts, Switches and Cut- outs. Measuring Instruments, Induction Coils, Transformers, Motors, Dynamcs, 394 Pages, 350 2.00. Book Depart- ment. es Science Monthly, 225 West 39th Street, New York. Wireless Telephone, etc. ens. Price $ WRITE the Words for a Song. We write music and guarantee publisher's acceptance. Submit poems on war, love or any subject, Chester Music Co., 538 South Dearborn Street, Suite 111, Chicago. SONG that Stirred the Nations—‘‘Go, My Son, God Bless You,” 25c. Sovereign Publishing Company, 160 Sycamore, Buffalo, New York. YOUR Song May Make Your Fortune, We revise poems, compose and arrange music, copyrignt, advertise, publish, sell. Send for Booklet A. he Songwriters. — i026 South 51 Street, Philadelphia,

FOR SALE PHONOGRAPHS AND RECORDS

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F.. a INDUCTION Motor Winding Dia- 1, 2, 3 phase; Star Delta, 2 to 12 doles inclusive. Postpaid, $5.00. lass, 2819 East 8th Street, Kansas City, Missouri. MAKE Dry Batteries. Simple, ee instructions with ‘blue pri Dirigo Sales Company, Bath, vial ne WE WRITE Business-Building letters, Advertisements, Circulars and Booklets, at attractive rates. Results guaranteed. What is Your problem? Criterion Service, Dep't. 1, West New York, New Jersey. READERS of Popular Science Monthly— here’s your chance: We have on hand 200 copies of bound volume No. 88—January to June 1916; 25 copies of volume No. 89— July to December 1916; 25 copies volume No. 90—January to June 1917 and 500 saree et, of volume No. 91—July to December These copies are beautifully bound in heavy gray — with dark green backings, containing ¢ he words “Popular Science Monthly,” the volume number and: months included. Each volume comprises’ 960 ~ ms ,306 articles and 2,082 pictures. ust the thing for your library. A ten page index enables you to find in a moment any article or picture desired. Contain no ad- vertising whatever. At the present cost of gg B mater, these volumes should retail at $5 You can secure them now for $2 OO arch paid. Classified Department, Popular Se pot Monthly, 225 West Thirty-

UNIVERSAL igh Shelf—the shelf of a thousand uses, postpaid, 60c. Agents Wanted. Attractive Ppocklet’ free. George Gaylor, Clearfield, Pennsylvania. LET me send you C. O. D. one of my high- grade Razors. A regular $3.00 value. We have a limited stock which we are selling at $1.50 while they last. Send no money, order today. Dan Williams, Box 135, Odin, Ill. FAVORITE Printing Press—will sell rea- sonable, 242 McLean Avenue, Yonkers, New York.

FLOWERS, SEEDS AND PLANTS GATHER Roots and Herbs. Now is the time. Book of instructions, high war prices and address of buyers only 20c. We Medical Plant Company, West Milan, New Hampshire. FRESH Flowers delivered any city by co-operative organization florists. Send order with remittance to National Floral Corporation, 221 Broadway, New York. Booklet free. EVERYMAN’S PLEDGE — America shall win this war! Therefore, I will work I will save, I will sacrifice, I will endure, I will fight—cheerfully, and ‘do my utmost— as if the whole issue of the struggie depended

ninth Street, New York City. When writing on me alone. ALL Phonograph Records Bought, Sold, rented, exchanged. Save 50%. Catalog free. Six 10-inch standard selections prepaid, $1.50. Cut Rate Record Exchange, Box 483, De- troit, Mich. BUILD a genuine Choraleon Phonograph and save over half. Fine profits building and selling. We furnish motors, tonearms and necessary ‘parts. Send for our catalog and free blueprint offer. Choraleon Co., 2306 Monger Bldg., Elkhart, Indiana. BUILD your Phonograph. Highest quality motors, tone arms, reproducers, cabinets. Big Saving. Handsome catalog free. Indiana Phonograph Supply Co., Indianapolis, Indiana. “QUICK-ACTION Advertising—Eow it is Building Business for the Progressive Advertisers of America.’’ A little story of Results, told by the advertisers themselves— not the publiser. You will be interested in reading the little booklet we have prepared ‘a copy of which will be gladly sent upon re- quest. It may solve YOUR problem. D. W. Coutlee, Classified Pepeeunges. Popular Science Monthly, 225 West Thirtyninth- Street, New Yor : THE Real Estate Educator—A Book for hustling real estate boosters, promoters, town builders and every man who owns, sells, rents or leases real estate. Covers tully ee Compensation Act, In- come Tax Emeotover’s Liability Act, Statute of Frauds, How to Sell Real Estate,’ How to Become a ‘Notary Public or Com- missioner of Deeds, ‘‘Pointers,”” ‘‘Don'ts" — acy information. 256- Pages, Cloth. $1.00. Book pepertmnens Popular fiehenne Monthly, 225 est 39th Street, New York.

to Advertisers please mention Popular Science Monthly

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22 AUTHORS—MANUSCRIPTS Popular Setence Monthly REAL ESTATE—FARM LANDS FOR INVENTORS WANTED MSS. for placement—Stories, = photo part, i —_ erton Agency, 569 fest 150th, New WRITERS: Stories, poems, plays, etc., are wanted for publication. Literary Bureau, 1i7, Hannibal, Mo. WRITE for newspapers and magazines. Big “wy. Fate oe unnecessary; details free. ess Reporting Syndicate, 400, St. SEE Here! We want your peers and stories! Criticized Free. Id on commission. Send for guide. Ms. Sales Co., Dept. No. 6, Poughkeepsie, N. Y. ideas for $10 DOWN, $5 a Month for a fine little farm of your own. 10 acres, $300. Poultry, fruit, truck make good money. Michigan’s — County. Mig towns, schools, churches. ts. Full information free. long wort 38 S. Dearborn, Chieago. CALIFORNIA [Kittle farms near Los Angeles for sale. Easy terms. Write E. R. Waite, Shawnee, Oklahoma. OWN your own Orange or Grapefruit Grove in beautiful Fruitland Park. Let me tell you how melons, peaches, hay, your first eros, rs rl! for your land and grove. J. Desk 205, Fruitland Park, Flori = “WANTED—Stories, articles, poems for new magazine. We pay on aeceptance. Handwritten Mss. acceptable. Send MSS. to Women’s National Magazine, Desk 251, Washington, D. C. WE WRITE Business-Building Letters, Advertisements, Circulars and Booklets, at attractive rates. Results guaranteed. t is Your problem? Criterion Service, Dep't. 1, West New York, New Jersey. I Want to send you proof of the wonderful poles — of the Classified Columns of magazine. If you want to buy some- thing, sell something or exchange something, write today for full. * particu ulars. D. Coutlee, Adv sian: Manager Po ‘opular Science Monthly, 225 West 39th Street, New York. EDUCATIONAL AND INSTRUCTION STODY at home. pases » beotiecese. can keep Keeping after | ‘stu dying this rful system. Blade “sad Method, 2009 Citton Avenue, Chicag WE WRITE ane rege Letters, Advertisements, Circulars and Bool:lets, at attractive rates. ults teed. What is Your Problem? Criterion Service, Dep’t. 1, West New York, New Jersey. ORNAMENTAL Casting, make moulds » two hundred illustrations Free. Woodhaven, Long Island, N. Y. “SPANISH-IN-A-WEEK,” by T. S. The best text-book to the great Latin-America. Embodying a new method, scientific, exact, comprehensive, by an ex teacher of pure Castilian % his book contains the elements the e, easily and of a vocab to enable —— to obtain working Soontenee of S .. Every werd Widely used by phonetically pronoun export houses, engineers, “salesmen, students, teachers and travelers. Price 50 Cents. Book Department, Popular Science Monthly, 225 West 39th Street, oNew York. PA, iy cm w Ideas. Write for list + ——— and Inventions Wanted. $1.0 ~~ Bey a yt ys four Boo Vicwor Evans & oe 178 Ninth. Washire . I Want to send you proof of the wonderful pulling power of the Classified Columns of this magazine. If you want to buy some- thing, sell something or exchange something, write today for full particulars. D. W. Coutlee, Manager Classified Department, Popular Science Monthly, 225 West 3¥th Stree,, New York. FIND Out for Yourself wh and how to procure and seil ee to 1eurent the same. My book, ‘Inventor t for Educator,’’ covers the Matter 8 Un A Vergal 140 pages, elegantly bound. Also eon: 600 mechanical movements and Guta etual —— Price § $1.00. 00, postage fre . dieteric Oura ington, te OF J Wash PATENTS without advance attorney fees. Free report and books, rank Fue Washington, D.C. HAVE you an idea? If go, shou —- » £ yen Send You sho or sketch for free opinion of tabi, Write for our Four Books of ateatab address. Victor J. Evans & Co., Washington, D. C. 156 N Nua, INVENTORS—We specialize ‘in facturing new patented articies, models—dies—and do a work, Leo J. Gerding Mfg. Co., Dept. E Place, Cincinnati, Ohio. IS He Crazy? The owner of a plantation in Mississippi is giving away a few five- acre tracts. The only condition is that figs be planted. The owner wants enough fizs raised to supply a Canning Factory. You can secure five acres and an interest in the Factory by writing Eubank Farms Company, 934 Keystone, Pittsburg, Pa. They will plant and care for your trees for $6 gts month. Your profit should be $1,000 = F ear. jas thing this man is cra7y or giving away such valuable land, but there may be method in his madness. potty, Sy Farms—15 States— 10 an acre up. , tools and crops often included tc 3ettle yo Write for Liz Tiustrated Catalogue. Strout Farm Agency, Dept. 12, New York. FOR MIN AND WOM=N YOU can turn your spare time into dcllars by taking as from your friends and acquaintances. @ regular reader of Popular Science Monthly, know its good + nts and can present its attractive features n a way which will readily secure a large number of subscribers. Convince me a you are in earnest and willing to take- vantage of this opportunity, ami I will ae send you full particulars as to how to go about the work, and also special appointment papers for your territory. Don’t wait until — neighbor has secured the ee tees write today. Circulation Director, Popular Science Monthly, 225 West 39th Street, New York. INDIAN Baskets—Wholesale and retail, Catalogue. Gilham, Highland Springs, California. “SEXUAL Philosophy,” 12. Clear, specific, authoritative, Wy os best satis- fies. Fred B. Kaessmann, Lawrence, Mass. WE WRITE Business-Building Letters, Advertisements, Circulars — Booklets, at attractive rates. Res guaranteed. What is Your Problem? ults Criterion Service, Dep’t. 1, West New York, New Jersey. STUDENTS: Get this Complete Course in Bookkeeping by L. B. ughan, Ph.B. ness Coles. Chi Te book (7x10 in.), Eleven Tlustrated Blank Books (8)4x13 34 in.), ). Hens, Penholders, Pen- cils, Red Ink, Rul ring er, Tablet, Writing lt also Business (explained and illustrated), Rapid ¢ Caleula- tions, and a special 96 page ‘book on Writing, designed as a Complete Course in Business Penmanship. 8 ly boxed, price $7.59. teed. Criterio tisfaction guaran a m Service, West New York, New Jersey. SIMPLIFIED Bookkee: .— and Stenog- raphy: practical, easy. ome study book- lets, 25c each. ‘Stenographer, B285, Nash- ville, Tenn. BUSINESS Letter Writing Taught in Ten Lessons. to write ferceful, magnetic pm ones and earn big salary. Practical letter experts will personally direct your work, Satisfaction teed. $1 brings fi lesson. Partievlars free. Puffer & Walsh, 120 Greenfield St., Buffalo, N. Y. WORLD-ROMIC 8 Masterkey all languages. Six text books, $1.44. French chart, 37c.; Spanish, 37c.: Aviation diction- ary, $1.59. Languages, 143 West 47th, New York. BE a Detective. 91d opportunity good pay, travel. Write C. T. Ludwig, 424 Westover Bidg., Kansas City, Mo. WHAT Do You Want to Know?—In- formation vital to the student, the experi- menter, the business man, or any inquirer given a 2 experts. Educational, Scientific, 2g: Business questions answered. Ask us the points you cannot find out any- where else—we usually know. No charge if unsuccessful, small fee of $1 if we set you right. Send your questions direct from this ad, or write for our complete proposition, free. The Kent System, Department A, Cambridze, Mass. Free Booklet. value of your mh. ttion. Fredk. Ooten, Sta. F., Philadelnhia, Pa. gs: INVENT Something. Your ideas, map may Send postal for F Tells what to invent and how S obtalny a alber through our credit system. Talbert es 4691 Talbert Building, Washing ton, D. i PATENTS on easy payments, model or sketch for free search and registration of your invention for your tection. Free book tells what to invent t and how to a, & patent on easy payment, — es & Co., win Loan and Trg Biag., Washington, D. » PATENTS that protect and Pay. - Adve and books free. Highest references. Bag ” results. Watson E. Coleman, Washingt, D.C. WE will commercialize and manufac that electrical or mechanical invention fg you. Confidential development and : mental work. Tools, dies, and nan Precision Engineering cms +» 2914 Ave., Cincinnati, Ohio HAVE You a Patent to Sell? My methal — will enable you # a in touch vith j proper ersons. today for detail, — | rite — 22 W est 39th Street, York City ie: BEFORE spending money patenting invention try selling it. For vual Dew suggestions address ox onal D ment Company, Dept. F, 922 F 8t., washing ; ton, D. C INVENTORS—Can place patents vey | quickly. = Jonap, Marlon B uliding Cleveland, Ohio. WRITE us if you want to sell or patent your invention. Free confidential advice, Smith’s Patent Office, Publicity Bulding Toston, Mass. DRAWINGS, Models. Specialists a gas engines and aeroplane work. Arta. Haar Company, 1269 Broadway, New w York, INVENTORS: Cash or royalty pald fer nd invention or patent. Square deal a& . _References furnished. 1898. We secure patents, form companies, make models and manufacture for the mat kets. Send sketc h, a “i patent at once 50., , Railway Ex change, St. Louis, Mo INVENTORS—Join National Inet Inventors, World Bldg., New York. bership 1700 strong will’ help Re: and market inventions; mutual benevolent brotherhood association, not business enter prise. Write for booklet. BEAUTIFUL Rubber Bathing Cap. Any color. Postpaid 50 cents. Superior Rubber Works, Ashland, O. ZODIAC Horoscope Reading showing character, talents, possibilities, invaluable for your ‘life guidance; send birt orn a ieath, 10¢ (coin) for Trial Reading. E. Dept. P, Crown Point, Ind. EVERYMAN’S PLEDGE — America shall win this war! Therefore, I will work I will save, I will sacrifice, I will endure, f will fight—cheerfully, and to my utmost— as if the whole issue of the struggle depended WE do Experimental work, make workilg models, wood and metal patterns, blanking, forming and piercing dies. Light man facturing on contract. Low prompt service. General 5 & : orks, 19 4th Street, N. E., Mason City, owa. I want to send you proof of the wi pulling power of the Classified C this magazine. If you want to buy some write today for full particulars. D. Coutlee, Manager Classified Ad Popular Science Monthly, 225 West on me alone. When writing to Advertisers please mention Popular Science Monthly Street, New York. oven } thing, sell something, or exchange 80! i

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BSS 1 = eT 5. es CORT RL FSCAASE IRS! AOR! AS) TORR! APRA) POSES! POS! BERPRE! SHoFG! PEE! BFEE! PENSE! All PeFE: pATENTS AND PATENT ATTORNEYS ——— ly Procured. Send PATENTS, . Rig Ta ctual ae (0-Pa: aten 1918 Bao service gets — value uld never require more for my cliente, aan 4 upon the patentability bro invention; nor longer than 10 days to prepare our case = filing. Longer delay = 0 neglect and the jeopardizing of of our Ti our lets For prompt personal service we aing, Ger ashington, Popular Science Monthly PATENTS—Herbert Jenner, torney and — expert, Py St, Washington, D. I report free a charge if a patent can 4 had and its exact cost. Send for circular. PATENTS Wanted—Write for List of Patent Buyers who wish to purchase patents and What to Invent with list of inventions wanted. Send sketch for free opinion of patentability. Our Four Guide Books sent free upon request. Patents advertised free. We assist inventors to sell their inventions. Victor J. Evans .& Co., 155 Ninth, Wash- ington, D. C. potent at- P. Kimmel, 38-F Oriental D.C. NVE need my free books oP NYE snd Successtul Promotion.” Tell. ideas can be turned into money, advice free. Real personal ourviee. a. references. Lloyd W. Patch, 23 roit Bldg., Washington, Dp. C. Books, deas. “How to Or Patent.” — “What to rots tch for fr sent free. Send rough ske Manufacturers 3 eye 4 ; Wh ge for sale a Chandilee. ventions must be pat- fe pe eaueerion. while being per- Write for a free oem as to the tentability of your idea. Beale & Park, 422 F Street, Washington, D. C. nt Attorney, McGill wided iekington ig Cc. Inventors’ Pe book, “protecting, ‘Exploiting and Selling Inventions,” sent free upon request. i TS and Patent Possibilities’’ is a mane which tells all about patents, what to invent and where to sell it. It gives ——- advice to inventors and tells about the of some of my clients, am xe frequent causes of fa twat carers ore constantly writing for ol patents upon all kinds of sound day. 8 Washington, D Trade Marks, Copyrights. Prompt, personal, reliable service. Over 30 years’ active practice, Difficult and Re- Cases icited. Write for terms. Book free. Address E. G. Siggers, Box 1, N. U. Building, Washington, D. C. .-PATENTS: Our practice before the Patent Office extends over seventy years. It pays to mee an attorney of reputation as a poor patent is a investment. Ability and Rehability are our special partners. We = a. the publishers of the Scientific and all patents secured by us are Shek without cost in the Scientific Amer- fean. Your invention is thus brought to the attention of thousands of intelligent readers especially interested in such matters. To procure ‘ike publicity in any other manner would cost = many times the patent fees. Our hand Book on Patents sent free on pang Munn & Co., Patent At- rneys, 624 Woolworth Building, York: read 625 F St., Washington, D. C. BEFORE spending money patenting your invention try selling it. For particulars and suggestions address International Develop- ae epeany, Dept. G, 922 F St., Washing- on, D. gt ae ae sketch for free search repo! Books on patents, book of reference letters, ag —— “A table novelty sent free. John S Co., F () Street, Washington, D PATENTS ey through D. Swift I ape sold to Large Manufacturers. ite today for free books of ‘‘Inventions "and surpassing references. Swift, 371 Seventh St., Washington, D. C. Established in 1889. PATENTS Bring Riches. Protect Your infention. Attorney's fees payable when end as Plain advice and ‘Patent free, Trade-marks registered. Jaynes sad Jaynes, 600 Kellogg, Washing- YOUR idea wanted. Patent your inven- tem I'll help you market it. Send for 4 free books, list of patent buyers, hundreds of = 3 anted, etc. Advice free. Patents tan iy ll Bad, B. Mh sates ashington, D , ven ¥ Woolworth Blidg., New York. | Washington, D. C PATENTS that protect and pay. Advice and books free. Highest references. Best results. Watson E. Coleman, Washington, D. C INVENTIONS of merit can be sold by our system. For further particulars. write Washington, American Investment Co., D. C. AMERICAN Patents and Trade-Marks. F. V. Winters, Patent Lawyer, 125 East 23rd Street, New York City. Secures patent pro- tection everywhere. ‘Telephone Connection. FITZGERALD & CO., Fayent Lawyers, 801 F St., Washington, bd. C. Eat. 1880, “The Old Reliable Firm.” i ree handbook. DON'T lose your rights to patent pro- tection. Before proceeding further send for our blank form ‘‘Evidence of Conception”’ to be signed and witnessed. Book, suggestions and advice free. Lancaster & Allwine, 232 Ouray Building, Washington, D.C THE Patentome is free. An education in obtaining patents. Established 1865. An- derson Son, Attorneys, 712 7th St., “QUICK-ACTION Advertising—HtHow it is Building Business for the Progressive Advertisers of America.” A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in reading the little booklet we have prepared, a pod of which will be Bid sent upon re- est. It may solve YOUR problem. D. W: Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. INVENT Something. Your ideas may bring wealth. Send postal. for free book. Tells what to invent and how to obtain a patent through our credit system. ‘Talbert 3 =— 4624 Talbert Bldg., Washington, YO Marxet Your Invention, you must get in touch with the proper persons. Let me show you how to doit. D. W. Coutlee, 225 West 39th Street, New York (¢ itv INVENTORS: We undertane sale of atents we obtain. Write Fisher Mfg. Co., Disc. Railway Exchange, St. Louis, Mo. Agents. PATENTS! Foremost word free. Metz- ger, Washington, D. C. PATEN'!(S, make your ideas pay. Hun- dreds inventions are sold yearly. We help _— yours free. Book and advice free. M. Buck & Co., 534 7th St., Washington, i. Cc. PA'TENTS on easy payments. Send model or sketch for free search and Certified registration of your invention for your pro- tection. Free book tells what to invent and how to obtain a patent on easy payments. C. C. Hines & Co., 592a Loan and Trust Bldg., Washington, D. C. Prominent New York business men desirous financing meritorious inventions protected by me. Send your ideas. Honest advice and ‘Truth about Patents’’ free. J. Reaney Kelly, 742 Woodward Bidg., Washington, D. C. PATENT applications filed on partial ayment plan. We help sell the patent. frade-marks, copyrights, etc. Milo B. Stevens & Co., 640F St., Washington; 351 Monadnock Bik., Chicago. Estab. 1864. PATEN’L’S tnat rrotect. Write us for new book, ‘Patent-Sense,’’ worth more than all other patent books combined. Free Write Lacey & Lacey, 127 ornare Building, Washington, D. C. Established 186 “QUICK-ACTION Advertsing “aioe it is Building Business for the Progressive Advertisers of America.”’ A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in readng the little booklet we have prepared, a copy of which will be gladly sent upon request. It may solve YOUR problem. D. W. Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty- ninth Street, New York. When writing to Advertisers please mention Popular Science Monthly 23 PATENTS FOR SALE PATEN'T 1228413. Write to L. h. Harris, North McGregor, Iowa. TWENTIETH Century Window Screen or mosquito net on roller. Patented. For sale. State right or Royalty. Offer wanted. —— 484 Prospect Place, Brooklya, New ork. BELT Fastener, Filter, Natural Ice Making, patents for sale ‘or on royalty. E. Seavey, 359 Pearl Street, New York. BE A geo age Rt a ~~ a ractical invention ney. rite Fisher Mfg. So. apts3B I ee Ex- change, St. Louis, N FOR SALE Patented Steel Derrick, for hay, wheat and all other kinds of derrick work. John Koones, 16 North Forest Street, Chanute, Kansas. PATENT No. 1,240,8360—a National Household Necessity. Write for details. hoto and attractive offer. Levy, 494 fast 141st Street, New York. HELP WANTED MEN _ Wanted to make Toy Soldiers, Army, Navy and other toys. Homeworkers, on s scale, Manufacturers on large seale. -Great chance for industrious people for independent business. Enormous de- mand end; future in American-Made Toys. War stopped all importation. Another in- dustry taken from Germans. Exports for 1917 have been about $3,000,000. Toy industry is growing rapidly. Some people have started with 2 few casting forms some — ago, own big factories now. We are pm hy with single orders for over a llion for 1918. We also buy these goods for three years, paying fixed prices. Experi- ence or tools not necessary. Hundreds and more made co — per hour. Casting- forms outfits $2.75 up. All we state can be roved by facts. Booklet, informiation free. oy soldier Manufacturing Co., 32 Union Square, New York. BIG Pay for Men and Women. Tremen- dous demand for draftsmen. Pleasant work; salary $100 to $200 a month. Study spare time at home; we will help you secure position wae qualified. Write today for particulars. ecial offer to men subject to draft. Sebans ia School of eg ae 452 McLachlen Building, Washington, D. C. DETECTIVES make big money! Travel and see the country. We instruct you at a nominal cost. Write for free booklet. American School of Criminology, Scherer Bldg., Detreit, Mich. I WILL pay any honest man up to $50 monthly for part of spare time. No can- vassing. No soe. Write today. Voor- hies, Dept. P. S., Omaha, Nebraska. SEN Seiaat the branch of the Army you enter. Go as Motor Mechanics. Most desirable duties. Become Auto Experts. Earn $35 week at home. Sample Lessons free. i - age Institute, Dept P820, Rochester, N. SILVERING Ee Tartaric method one enormously profitable busi- ness. Booklet free. Barstow, 514 23rd Street, Oakland, California. WANTED three hundred young men to learn Watch-work, Jewelry-work and En- graving, in order ‘that we May be able to opply the demand on us for workmen. ress postal card to Bradley Polytechnic Institute, Department ‘‘M,”’ Peoria, IIl., asking for our latest catalog giving fuii particulars, BE a Mirror Expert, $3-$10 a day; spare time home at first; no capital; we train, start you making and silvering mirrors ngage method. Free prospectus. W. F. Derr, Pres., 579 Decatur Street, Brooklyn, N. Y. RAILROAD Traffic Inspectors Wanted. $125 a month and expenses to start; short hours; travel; three months’ home study under guarantee; we arrange for position. No age limit. Ask for eckset L10. Frontier Prep. School, Buffalo, N. Y EARN $900 to $1800 per Year. Govern- ment Railway Mail, Post Office and other “exams’’ coming. Prepare under Former Civil Service Eaxminer. Book free. Pat- terson Civil Service School, Box 3019; Rochester, N. Y. BE a detective. Excellent opportunity, good pay, travel. Write C. T. enews. 424 Westover Bldg.. Kansas City, Mo. EVERYMAN’'S PLEDGE — America eo win this war! Therefore, I will work, will save, I will sacrifice, I will — I vill fight—cheerfully and to my utmost, as if the whole issue of the struggle depended on me alone.

Page 24

24 U. S. GOVERNMENT wants thousands clerks at Washington, immediately, for war preparatory work, $100 month. Quick in- crease. Men—Women, 18 or over. 7 hour day. 30 days vacation. Easy clerical work. Common education sufficient. Your country needs you. Help her and live in Washington during these stirring war times. Write immediately for free list positon open. Franklin Institute, Dep't P50 Rochester, N. Y. BECOME Detectives—Lig wages, won- derful opportunities; Wagner, 1243 Lexing- ton Avenue, New York. WRITE Photopiays, $50 each. Experi- ence unnecessary; details free to beginners. Producers’ League, 194, St. Louis. READERS of Popular Science Monthly— here’s your chance: We have on hand 200 copies of bound volume No. 88—January to June 1916; 25 copies of volume No. 89— July to December 1916; 25 copies volume No. 90—January to June 1917 and 500 copies of volume No. 91—July to December 1917. These copies ar- beautifully bound in heavy gray covers with dark green backings, containing the words ‘Popular Science Monthly,” the volume number and months included. Each volume comprises 960 pages, 1,306 articles and 2,082 pictures. Just the thing for your library. A ten page index enables you to find in a moment any article or picture desired. Contain no ad- vertising whatever. At the present cost o1 Lig re Matter, these volumes should retail t $5.00. You can secure them now for $2. postpaid. Classified Department Popular Science Monthly, 225 West Thirty- ninth Street, New York Citv. MEN—Age 17 to 45. Experience unneces- sary. Travel; make secret investizations, reports. Salaries, expenses. American Foreign Detective Agenev, 321 St. Tovis

Popular Science Monthly AGENTS AND SALESMEN WANTED $1,000 per Man per County; Strange invention startles world—agenis amazed. Ten inexperienced men _ divide $40,000. Korstad, a farmer, did $2,200 in 14 days. Schleicher, a minister, $195 first 12 hour. $1,200 cold cash, made, paid, banked by Stoneman in 30 days; $15,000 to date. A hot or cold running water bath, equipped for any home at only $6.50. Self-heating. No plumbing or waterworks required. In- vestigate. kxclusive sale. Credit given. Send no money. Write letter or postal to- day. Allen Mfg. Co., 432 Allen Bbldg., Toledo, Ohio. AGENTS: 500% profit. Sign letters for office and store fronts, samples and par- N

ticulars free. Inter State Sik gn, 2422 Halsted St.. Chicago.

AGENTS—Ho-Ro-Co Skin Soap and toilet goods plan beats everything for agents’ profit. ‘tHo-Ro-Co.,"’ 133 Locust St., St. Louis, Mo.

SALESMAN: trade; large demand, pocket sample. Chicago.

liberal ‘commiasion, Wirth Salesbook Co.,

“EASY-Steps.”’ scientific foot comforters; all sizes; quick, big sellers; dozen pe $2.25; profit 200%. Samples 25c. fanhattan Popular Products, Brooklyn, N. Y.

HEL-MIT the Kaiser Pin—Latest war novelty—Bigrest Hit Out; oxidized silver; thousands being sold; simple matter hand- ing them out and taking money: sample with agents’ terms 10¢. O. Finch Company, Grand Rapids. Michigan.

FORD Lock—Good agents’ a. Brackbill. 1301 MecFarran “t.. iladelphia. INVEST $2.50 for a comp) %-in. Old English Transfer Initia aa gram automobiles, ete. a Mow $27.50. Particulars free. be. ret comanie Co., Lept. 1, Jersey cnet N.J. 300% PROFIT—Agents Clean dreds Weekly. New W ashing es Eu. Wonderful seller. Big repeater “oN mightiest Cleanser. Send 1314 ¢ Gy “<n

sample. K. Mitchell, Chicago.

NEW Patented C utter, for paper, ina etc. Uses razor blades. " Adopter =a ers, artists, decorators, Dnetoerephe ey card writers. Price 25¢c. E South Grand Avenue, + ‘ine on

SALESMEN Wanted, New Side Dn Sells quickly to large or small city oe Lng banks. Pocket samples. Libera} comma sions paid when orders received B Service Exchange. I esk 10, ‘ved. Bane Pen LETTER - owner's initials on $1.50; pays 800% profit. Outfit co 3 ta $2.5); no skill or experience required; pros {obportunities; write for ea merican onogram oe D “ge ) arket St., Newark, N. ert. “8,” I WE WRITE ee Letter, Advertisements, Circulars and “Bod Ook let, at attractive rates. Results guarantees, What is your problem? Criterion cer, Jen't. 1. West New York, New Jersey. SALESMEN—City or Traveling. i be a unnecessary. Send for list ot ope, ngs and full particulars. Prepare time to earn the big oat A | Employment service Te Address nearest Lept. 126 G, Natl. Salesmen’s Tr. ( hicazo—San Francisco—New Yor.

EARN Extra Money during spare time mailing letters for us. No experience, cap- ital required. Send dime as deposit for supply of letters and contract. Deposit re- turned with first week’s pay. Hile Company, D-10, Carey, Ohio. INVENT Something. Your ideas may . Send postal for Free Book.

ata through our credit system. Talbert "Talbert, 4101 Talbert Building, Washing-

ee a — Print Expert—$25 to $5u a week in this new and fascinating profession. Write—find out oy! you can learn at home = supply the big d —— for finger print ~% —_ big factories, detective sanncies, etc iallimited offer—write while it Saal niversity, Finger Print Dept., Room 1206. 1810 Wilson Ave., Chicago. Nii. FOREMEN, Shopmen, and Otmcemen wanted to work spare time as special repre- sentative of large well known mail order house, Diamonds and exclusive sales rights granted. No invest- ment or deposit required for outfit or samples. Write at once for details. Ad- 8. iller, Dept. 52. Agency Divi- sion, Miller Bidg., "Detroit, Mich. MAKE money raising Belgian mares for us in your Sockyare. Write today for instructions. Mark Twain Stock Associa- tion, Dept. 193. Hannibal Mo BECOME chauffeurs, $35.00 Week, Learn while earning. Sample lessons free. Franklin Institute Dent. O 829. Rochester.

WORLD'S Fastest Selling Auto Accessory. County distributors oe: good profits; write today. G. L. . Spring Oller Co., San Dies. Califarn Tad $10 Daily refinishing chandeliers, brass beds, automobiles, by new method; produc- ing amazing results; no capital or experience necessary. Particulars free. Gunmetal Co., Avenue F., Decatur, Illinois. AGENTS—$30 to $100 a week. Free samples. Gold and silver sign letters for stores and office windows. Anyone can put on. Liberal offer to general agents. Metallic Letter Co.. 46) N. Clark, Chicago. WANTED SALESMAN—By one of the largest concerns in U.S. Salesman not sub- ject to draft to cover nearby territory. Ad- vertising Campaign supplies leads. Earnings in commissions run several hundred month. Expenses paid while training. d-

dress B. E. Harris, G. 8. M., K-1205, Monroe Bldg... Chicaro. OVER 500% profit applying transfer monograms on. automobiles, trunks, etc. Easily =. Directions and samples free. a agner Co., 299 Broadway, New

SALESMEN—Become independent—own your business, experience unnecessary selling our $6,000 Accidental Death,$30.00 Accident, $25.00 Sick Weekly Benefits. $10.50 yearly, half amounts $5.50. Guaranteed steady in- 50,000 deposited Registration Dept. come from renewals. $250 Insurance Department. S., Newark, N. J.

GET on the Stage. vaudeville career of- fered you. ge eed Ho ge A Man- agers endorse Instructive booklet free. "LaDelle, Sta, "79, Jackson. Mich. MEN—Women Wanted for Government

War Positions. Thousands needed im- mediately. salaries; permanent em- ployment; liberal vocations; other ad- vantages. We prepare you and you secure a — or we refund your money. Ask = klet “QL” free to citizens., Washing Civil Service Setnst, 2027 Marden Building. Washington, D. C. Pg ea Advertising—How it is Building unions for the Progressive Ad sone of America.” A little story of Results, told by the advertisers themselves— not the ‘publisher. You will be interested in reading the little booklet we have prepared, a copy of which will be gladly sent upon re- uest. It may solve YOUR problem. D. . Coutlee, Classified Department, Popular Science Monthly, 225 est Thirty-ninth . New York WONDERFUL Adding Machine—Seven column capacity—retails for one dollar. Sells itself everywhere. Most offices purchase several. Sensational agency proposition. L. J. Leishman Co., Dept. F., Ogden, Utah.

AGENTS make 500% profit handling Auto Monograms, Patriotic Pictures, Win- dow Letters, Transfer Flags, Changeable Signs. Catalog Free. Hinton Co., 6142 40th Court, Chicago, Til. IF you want to succeed—if you want to get ahead in the world, you must read. Are you interested in electricity, automobiles, gas engines, aeroplanes, metal work, drawing, engineering, chemistry or any mechanicai subject? Write for the new Book Catalogue of the Popular Science Monthly. It de- scribes the best and simplest and most easy to understand books on all these subjects. It is free. Popular Science Monthly, 225 West 29th Street, New Yor EXCLUSIVE county rights. modern auto fuel; profitable; Tankii Co., Cleveland, Ohio. PERFECTOR for Ford Motor oiling sys- tem. Newinvention. Saves \% to \ the oil. Less carbon. Less spark plug trouble. Motor runss moother. Installed in a few minutes without raising hood. No changes in motor or any adjustments. Fifty cents, postpaid. Inducements to agents, dealers and garages. Perfector Mfg. Co., Los Angeles, California.

Sell Tankii; guaranteed;

When writing to Advertisers please mention Popular Science Monthly PURE Food Cocking Recipe Cabin containing 400 locse-leai Conservation Ry — ipes. printed on 100 cards, together wit | ) blank cards, handsomely packed in Chi nut Cabinet. Wonderful Ponveniensail ev = ecg soe Rs vo $1.50; ne cen or sample to Waverly Com Rose Street. New York. d sa oi

NEW $2.50 Automatic Adder. Mag” maker for live agents. Quick cle a ees: no competition. Bassett, diana Avenvre. ( hicago.

SELL ‘America, We Love You.” Crt gees picture. Mr. Noyes, Maine, may 10 one evening. lLarge sample toe Sells for aset. Clement Moore, Publishe, New Feypt. N. J.

SPIRAL Spring Curtain Rods; wah tures; other big sellers. Get busy. Cireulgy ~

free. Moore Co., 3841 Jerome Ave., Ce cinnati. AGENTS: Screen Door Check. the bang and saves the door. summer seller. 100% profit. Demonstnt | ing sample free. Thomas Mfg. Co., 13l North St.. Davton. Ohio.

SALESMEN Driving Ford Cars—chane to make money on low-pri easy-selling accesory. Can be worked as sideline. High class proposition. Write today. Campanv. South Pend, Indiana. AGENTS—To Travel by Au troducing our Big Line of fast summe sellers. The greatest line on earth. Make $10 a day easy. Complete outfit and sue mobile furnished to workers. Write at once for excivaive, yey so American Products 2RAT . Cincinnati. Ohio. AGEN’ iS: A high-class ph Built right into a Wonderful tone—low price.

Easy to carry. casel. seller. Plays all reccrds. Write for demo strating sample. Orchestrola Co, 1 North St.. Dayton. Ohio.

EASY, pleasant work for Mechanics, Men, ¢ lerks, Saree one eee many dollars to eir sala persons who can give full time. as assured. Novelty Cutlery Co., 27 Canton. Ohio. DOUBLE your salary. Sell during spate time guaranteed silk hosiery and direct from factory to wearer. 500 5,000 yearly easily aoe. inte at oDee 4 for proposition. C. & , Dept. 10, Grand Rapids, M Bg $50.00 a week up. All the Free Prnag you want to wear simply to advertise Us. mt Write today for selfemeasuring blanks, chart, big book of samples, etc. money. A postal card brings all. —

expressage on everything. American W Mills Co., Dept. 6A51, Chicago.

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i SEF HFbehSEl SECA! RokaTIPSese | hesen! eeeer! Tees mem PaFl Rabel weal jessie | ESEe| S226! oa a5| vGae8] SsEeel s85e8 Ss becdee! week. New, patented, AGENTS Sinobe. No nails, no screws, rage netition. Demonstrate a a, 4 carried. 2 sample. Doe et. Co., 2561 North St.. Dayton, Ohio. ea it “ - N Advertising—How aa pe te for the Progressive y oa isers of America.” A little story of ‘ey told by the advertisers themsel ves— ts, Mblisher. You will be interested in ak med the little booklet we have prepared, & ; of which will be gladly sent upon re- pt It may solve YOUR problem. D. laa? tle, Classified Department, Popular a9 Monthly, 225 West Thirty-ninth D—New Ideas. Write for list of WANTED and Inventions Wanted. 00,000 in prizes offered for inventions. e Four Books sent free upon request. incor J. Evans & Co., 174 Ninth, Washing- ton, D. C. it free for 2 hours’ work. Show “£ re friends and make $5.00 an hour in your spare time. We show how. Costs thing to try. Write quick for measure blank and our handy sample outfit. All free. We deliver everything free. Look into this Paragon Tailoring Co., Dept. 6A51, Chicago. es, inner armour for Auto- ney Pe, veerent punctures and double mileage of any tire. Liberal profits. De- tails free. American Accessories Co., Dept. 97, Cincinnati, Ohio. CTURERS of a Famous OT ch want house-to-house can- vassers. Excellent proposition. Famous Products Company, Decatur, Illinois. You Ever Offered a Grocery Store? ou P Pr position Is Better. Let us tell you how you can handle Flour, Canned Goods, Provisions, and entire line of groceries, as well as Paints, Roofing, Stock Foods, Auto- mobile and Machinery, Oils and Greases. No rent to pay. -No investment in stock. Large ofders taken from samples. Goods of guaranteed and proven quality. Selling experience not necessary. Very rofitable work for “workers.” Address, Hitchcock Hill Co., Dept. 220, Chicago, Ill. Reference: Any bank or express company. HUNDREDS of Agents are now making goods to sell from Miller’s Guaranteed Manu- acturers’ Formulas. Wizard Washing Tab- lets—no wax, potash, lye. Costs 5c pound. Brings 60c. Eegoiene, only pure food sub- stitute for eggs at 9c adozen. Non-Alcoholic Tube Flavors. Many new sellers including latest Automobile Specialties. Carbo-Cide, the only recognized gasoline Intensifier- Decarbonizer—800% __ profit. Enormous sales. Fibro-Vac Guaranteed Puncture Plugger. Exclusive territory. Particulars or . Miller, Industrial Chemist, Tampa, Florida. “RADIO” Luminous Paint for resale. Big demand—big profits. Trial can, 50c delivered. .-American Luminous Products Co., Huntington Park, California. AGENTS, “Eggite,” the guaranteed sub- stitute for fresh eggs, Means eggs at 8 cents oe doz.; enormous demand everywhere; ig profits; sample free. Thomas A. Dough- erty, 157 East 47th St., New York. HOSIERY and Underwear Manufacturer offers permanent position supplying regular customers at mill prices. $50.00 to $100.00 monthly. All or spare time. Credit. J. Parker Mills, 2733 No. 12th St., Philadelphia. NINETY Per Cent. of Your Calls Turned into Sales! Wonderful Enthusiasm Follows Every Demonstration! Write at Once for Full Particulars of Our Line of Eradium (Luminous) Articles. Startling! Mysteri- ous! Everlasting! Novel! They Shine in the dark. Crucifixes, House Numbers, Bulbs, Se eee, ay. yt Foes. Sole urers. e Pioneer Corporation, 1263 W. 63rd, Chicago. * AGENTS—Steady income. Large manu- facturer of Handkerchiefs and Dress Goods, ete., wishes representative in each locality. Factory to consumer. Big profits, honest goods. Whole or spare time. Credit given, Send for particulars. Freeport Mfg. C 24 Main a Brooklyn, N. P iia Popular Science Monthly AGENTS: Sell rich looking 36 x 68 im- ported rugs, $1.00 each. Carter, Tenn., sold 15 in 4 days; profit $57. You can do Same. Write for sample offer selling plan; Sample rug by parcel I WILL pay any honest man up to $50 monthly for part of spare time. vassing. No capital. Write today. hies, Dept. P. S8., Omaha, Nebraska. FASTEST Dollar Seller on the automobile market. 0% to agents. Permanent re- air for inner tubes. Every motorist will uy. Consumers Mfg. & Supply Co., Minneapolis. Minn. 233 per cent profit selling Jubilee Spark Intensifiers to auto owners, garages; banishes spark plug trouble; sells like wildfire; ex- clusive territory; write quick. Jubilee Mfg. Co., Dept. P-6, Omaha, Nebraska. . QUICK, snap this winner; brand new, big profits; sells on sight; unlimited field; — free. Dept. 19, Sunnyside Co., 14 Sunnyside St., Danville, Va. 25 MINUTES Pay Dollars, demonstrating new $7.50 Adding Machine. Wonderful invention. Adds, subtracts, multiplies. Work equals $300 machine. Five-Year Guarantee. Sells everywhere. Splendid profits. Write Quick for trial offer and pro- tected territory. Dept. O, Calculator Corporation, Grand Rapids, Michigan. “QUICK-ACTION Advertising—How it is Building Business for the Progressive Advertisers of America.’’ A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in reading the little booklet we have prepared, a copy of which will be gladly sent upon re- quest. It may solve YOUR problem. D. W. Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. MAKE and Sell Your Own Goods. Machinery unnecessary. Expert Chemists advise. Special attention to beginners. Write for Formula Catalog. Elmer Mystic Com- pany, Washington, D. C. “AGENTS:—Specialty Men sell the Sim- plex Auto Brush, new auto and wagon washer fits any hose; sure, quick cash sales; free samples. Francis M. Mfg. Co., Harrisburg, Pennsvivania.” ‘AGENTS. Big money selling Wardrobe Odorizers, sample 35c., particulars free. — & Co., 2935 N. Clark St., Chicago, nois, AGENTS: Our new invenu-ns will earn you steady income. Canvasse:3, County Rights Salesmen and Promoters write Fisher Mfg. Co., 2183G, Railway Exchange, St. Louis, Mo. BUILD Permanent, Profitable medicine and toilet preparation business. Agents selling Alfalfa’s Products eight years. Fully Guaranteed, 56-page book, particulars Free! Alfalfa, 850 Northwestera Building, Chicago. AGENTS: Big profits. Best and cheap- est window letters made. Easily applied. Dime brings five samples. Auto Monogram letters. Particulars free. Staibrite Company, 1115 Second Avenue, New York. “GASOLINE Saver For Fords: principle; saves 30% gasoline; gives 30% more power. No moving parts; put on with wrench in 10 minutes. Price $1.50. Guar- anteed. 100% proposition to agents. Thé Little Cyclone Accessories Co., Dayton, Ohio. SELL beautiful fragrant California Rose- beads. Absolutely new. Big profits. Cat- alog free. Mission U2819, West Pico, Los Angeles, California. PRESTO, Slip up Your Sleeves over Elbows, without unbuttoning. Cuffs open and close automatically when raised or lowered. Great convenience. Abnormal rofits. Sells everywhere. No competition or competent salesmen who sell direct to wearer. Enclose stamp. Flexo, s., Sheboygan, Wisconsin. STOP Here—sell the Eisen Regulator for Ford Headlights. Going like wildfire every- where. Gives splendid driving light at low speed—keeps bulbs from burning out— operates automatically. Wanted for every Ford. Big poe quick. LISTEN: Siler, Okla., sells 12 daily, profit $20. McFarland, Nebr., made $3,420 in 17 weeks. No ex- perience necessary—we show you how. Not sold in stores. Sales guaranteed. No capital necessary. Write today for special offer. Address Eisen Instrument Co., 695 Valen- tine Bldg., Toledo, Ohio. IF You want live, active and intelligent agents and salesmen to handle your goods, let me show you how to reach them. D. W. Coutlee, 225 West 39th Street, New York City. GET Davis’ {918 Prosperity Offer—Best in 21 Years—Our~-Food, Soap and Toilet Goods cut store prices 4 to 4%. Everybody buys to lower living cost. E. M. Davis, Dept. 51, 910 Lake St., Chicago. New DON’T scrape or burn carbon out of auto- mobile motors. Dissolve it with Carbogon. Tremendous demand. _ Big sales. Details poo Carbogon Co., Dept. 26, Cincinnati, 0. SOMETHING NEW and salable. $2,500 death and $15 weekly sickness and accident benefits cost $5 yearly. Identification in leather bill fold. Insures both sexes, 16 to 60 years, regardless of occupation. Apply for territory. Liberal terms with yearly renewal commission. Our agents are making money. Southern Surety Co., 308 Walnut St., Philadelphia, Pa. AGENTS. Enormous demand for light Truck Attachments. Sell the Burlington Better Truck Unit. Equipped with Torben- sen Internal Gear Axle. Every Ford a pros- pect. Exclusive territory. Write Burling- ton, Roye! Ins. Bldg., Chicago. DON’T wash your automobile. Dri-Klean- it does the job without water. Wonderful demand. Big profits. Details free. Dri- Kleanit Co., Dept. 26, Cincinnati, Ohio. SALESMEN, for _ Miultipost Stamp Affixers and Parcel Post stamp machines. Every office a prospect. Well advertised and territory circularized. Whole or part time, or as a side line. Liberal commissions. saan Company, Dept. C, Rochester, AGENTS seeking first class auto ac- cessory, see Hydronizer under “Automobiles and Accessories.” TAILORING Agents: Take no chances with uncertainties. Line up now for Fall with an organization that will make good. Largest woolen stocks, proper and efficient help—insure your profits. The Fall Ccm- mercial line will be the strongest popular eae tailoring proposition in the country. Write to-day for particulars. Commercial Tailors, 502 South Wells Street, Chicago. AGENTS: Big money, spare time, mono- gramming automobiles, cycles, etc. Particu- lars free. Waterbury Initial Company, 809 North Main, Waterbury, Connecticut. NEW Invention—one drop of rain closes window. $2.00 sample postpone for $1.00. See Popular Science Monthly, April, page 506. Address Automatic Window Company, 2107 North Percy Street, Philadelphia. Salesmen and District Organizers with Ford Cars to sell Simplex Ford Starter, the only mechanical starter with a reputation for making good, More than 16, in use. Fits any Ford Car. ‘Sells for $12.50. Write for agency—Box 250, Simplex Mfg. Co., Anderson, Indiana. WANT Territory Manager. Patent Port- able Window Ventilator for homes, public institutions, offices and factories. Big sales everywhere. Liberal selling arrangements. Write Esner Mfg. Co., Peoria, Illinois. “QUICK-ACTION Advertising—How it is Building Business for the ogressive Advertisers of America.’’ A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in reading the little booklet we have prepared, copy of which will be gladly sent upon re- quest. It may solve YOUR problem. D. W. Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York . BUILD a business of your own. Enjoy independence. Sell our $5,000 Health and Accident Policy with $25 weekly benefit for $10 yearly. You get all products on yearly renewals. rite today. North American exclusive territory. Prepaid, 98c. E. Condon, Importer, ass. 2 Pearl Street, Boston, M IF you want to succeed—if you want to get ahead in the world, you must read. Are you interested in electricity, automobiles, gas engines, aeroplanes, metal work, drawing engineering, chemistry or any mechanical subject? Write for the new Book Catalogue of the Popular Science Monthly. It de- scribes the best and simplest and most easy to understand books on all these subjects. It is free. Popular Science Monthly, 225 West 39th Street, New York. SPIES burning buildings everywhere. Enormous demands for Richmond Chemical Extinguishers. They kill gasoline or any fires. Sales Managers make 500 Accident Insurance Co., 904 Bonnell Bldg., Newark, N. J. When writing to Advertisers please mention Popular Science Monthly % profit, Richmond Chemical Co., esk 263, Wheeling, West Virginia.

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86 BUSINESS OPPORTUNITIES DIE-CASTINGS—I want you to buy Blue-Prints of a Die-Cast machine, moulds and instructions. Start in this money mak- ing business in spare time in your cellar, Garage or Barn. If you are a mechanic you know the possibilities. You have been look- ing for jst, such a chance and here it is. Curiosity seekers don’t write. Send twelve cents in stamps for my proposition, this covers cost of printing and postage. You ean’t get this proposition anywhere else at any cost. R. E. Byrd, P. O. Box 227, Erie, Pa. A SNAP for Mail Order Dealers. Quick gales, 400% profit. Particulars free. No free samples. Sterling Co., 148 Broadway, Newb’ ue & PUNCH No Man’s Time Clock. Stop ding for others; be no man’s slave. a little business of your own. I made .00 week, evenings, home. Free booklet how, 2c postage. Al Scott, Cohoes, New York. WONDERFUL CHANCE — Your per- sonal shirts and furnishings at wholesale ; _— Good salary as local representative moments. Send 15c for outfit. & Co., 252 Duratex Bldg., New York. “KNOCK the Helmet Off the Kaiser’ and “Royal Neck Stretcher.” Latest and best games for parks, carnivals and resorts. Big money makers. Small investment. Penn Novelty Co., 908 Buttonwood Street, Phila- deiphia, Pennsylvania. A BUSINESS of Your Own. Spare time. Make and sell your own goods. Information free. American Technical Laboratories, 600 Fifth Avenue, New York. DOLLARS yearly in your backyard. No Ginseng, Mushroom dope. New ideas. Investigate. Particulars free. Sunshine Co., 174 East 88th, New York. WRITE for newspapers and magazines, Big Pay. Experience unnecessary, details free. Press Reporting Syndicate, 4005, St. YOUNG MAN: Improve your mecianical efficiency. Send for my complete catalog of valuable books—it’s free. I also have boo on Human Nature, Thought Culture, Mind Power, Hypnotism, Mesmerism, Personal Magn Seership, Spiritualism, Clair- voyance, Concentration, etc. Tell me your — A. W. Martens, P-18, Burlington, wa. Popular Science Monthly BE A Manufacturer! Buy and market a invention and make money. Write Mfg. Co., 2183DD, St. Louis, Mo. WE WRITE Business-Building Letters, Advertisements, Circulars and Booklets, at attractive rates. Results guaranteed. What is Your Problem? Criterion Service, Dep't. 1, West New York, New Jersey. AUTOMOBILE lettering yields. big profits. New method . Easy, pleasant, fasci- nating spare time employment. Miller Sales Company, Lexington, Kentucky. MEN, Here’s One Way to Save Money! Save your razor blades for me to resharpen. My “Sure Sharp” process guarantees _per- fect shaving edze or money back. Write today for Blade Box and price list. J. A. Thompson, 106 Thompson Bidg., Baltimore, Maryland. READERS of Popular Science Monthly— here’s your chance: We have on hand 200 copies of bound volume No. 88——January to June 1916; 25 copies of volume No. 89— July to December 1916; 25 copies volume No. 90—January to June 1917 and cuptes of volume No. 91—July to December 1917. These copies are beautifully bound in heavy gray covers with dark green backings, containing the words “Popular Science a. * the volume number and months are 960 —. 1,306 articles and 2,082 pictures. ust the thing for your library. A ten page index enables you to find in a moment any article or picture desired. Contain no ad- vertising whatever. At the present cost of printed matter, these volumes should retail at $5.00. You can secure them now for 00 each, postpaid. Classified Department, ‘opular Science Monthly, 225 West Thirty- ninth Street, New York City. MAKE money in a new idea advertising business. Small capital. Start in spare time. Complete $1.00 twelve lesson course, ee, illustrated, only 10c. American Mailers’ Union, Brooklyn, New York. YOUR idea wanted. Patent your inven- tion. I'll help you market it. Send for 4 free books, list of patent buyers, hundreds of ideas wanted, etc. Advise free. Patents advertised free. Richard B. Owen, Patent Lawyer, 44 Owen Bidg., Washington, D. C., or 2276Z Woolworth Bidg., New York. MANUFACTURERS: I furnish un- patented ideas for novelties, useful articles, on cash or royalty basis. D. W. Pettijohn, General Delivery. Spokane, Washington. PICTURES AND POSTCARDS EXCHANGE Postcar, i Res oe Membership 10c. Jolly “Gard Club, Decatur, Indiana. Exchange, 10 Nice Postcards, membership, a 10c. 25—15e. Stewart © dence, Rhode island Company, ‘Prot POST CARD CLUB Membership in Write Princess Harmony § Lox, 412, Burlington, Vermont, — Bor SCENERY FOR HIRE BE Business Broker; Earn $1,000 to $10,000 yearly—details free. Eydman Sys- tem, 721 Olive, St. Lovis, Mo. INVENT Something. Your ideas may bring wealth. Send postal for Free Book. Tells what to invent and how to obtain a atent through our credit system. Talbert a 4690 Talbert Building, Washing- ton, D. C. WOULD You Invest $10 for a rattling good prospect of receiving $243.70 yearly income for life? If so, communicate with Harrison Brothers, Branch 251, Pough- keepsie, N. Y. START original mail-order business. New methods, exclusive rights, dignified. honest, profitable. Small capital. ove Moore, Specialist. “er Fevnt. N I WILL pay any honest man up to $50 monthly for part of spare time. No can- vassing. No capital. Write today. Voor- hies. Dept. P. S.. Omaha. Nebraska. BE a detective. Exccllent opportunity, good pay, travel. Write C. T. Ludwig, 424 Westover Bidg.. Kansas Citv. Mo. FREE—3 Months to get acquainted; devoted to news and og eg The Western Miner, 2541 W. 37th Ave., Denver, Colorado. ARTIFICIAL Marble, Sanitary Flooring, complete instructions, $1. Ornamental cast- ing, concrete, plaster, papiermache, decora- tions, garden furniture, statuary, rubber moulds, electrometallurgy. Particulars, 200 illustrations free. Mahler, C-721 Woodland Ave., Woodhaven. T.. T.. “ew Vork. “QUICK-ACTION Advertising—How it is Building Business for the Progressive A little story of Results, told by the advertisers themselves— not the publishers. You will be interested in reading the little booklet we have prepared, a copy of which will be gladly sent upon re- uest. It may solve YOUR problem. D. . Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. FREE. The first part of a Success Mes- sage that thousands have gladly paid a dollar to finish. Send no money now, get pert one first. Frank E. Morrison, Lept. 1, 133 Broadway, New York. MULTIGRAPH Letters build business. Most economical and efiective advertising. Printing. Addressing. Low rates, careful work, service. Multigraph-Peecrless Letter Company, 241 Fourth Avenue, New York. MANUFACTURERS, Promoters and Patent Buyers are invited to write us stating the line of invention in which they are inter- ested, as we can supply their wants in any class of patents. Victor J. Evans Co., 152 Ninth, Washington, D. C. WE Start You in Business, furnishing everything; men and women, J to $200.00 weekly operating our ‘‘New System Specialty Candy Factories,’’ home or small room anywhere; no canvassing. Oppor- tunity lifetime; booklet free. H. Ragsdale Co., Fast Orange, N. J. MONEY in Minerals! List 10c. Min- erals identified, $1.00. Assayer, 620 Joplin Street, Joplin, Missouri. ENTER a new business. Earn $3,000 to $6,000 yearly in professional fees making and fitting a foot specialty, openings everywhere with all the trade you can attend to; easily by anyone at home in a few weeks, at small expense; no further capital required; no goods to buy; job hunting, soliciting or ency. Address Stephenson Laboratory, 15 Back Bay, Boston, Mass. EXPERT ‘Chemist will furnish Formula and Trade Secrets in all lines. Lists free. W. L. Cummings, Ph.D., 217 Standart S8t., Syracuse, N. Y. Continued on Page 28 SCENERY supplied—an every 7. _— rental. i Grain Springgarden, Phil: Pennay| vania. — ——___ FIREARMS AND ANTIQUES BUY, sell, exchange old-tim Modern yire-Arms. Antaees wanted." sie. an ensselaer, 805 Madiso Venue New York. r ae “QUICK-ACTION Advertising— is Building Business for the Frosmeas Advertisers of America.” A little story Results, told by the advertisers th , not the publisher. You will be interested fy reading the little booklet we have prepared, copy of which will be gladly sent upon fe quest. It may solve YOUR problem. D. A Coutten, ae Department, Popul cience Monthly, 225 W rty-ninth Street, New York. — DOGS, BIRDS, PETS COLLIE, St. Bernard, Newfoundlan and Fox terrier puppies. The intelliges kind. Prices very reasonable. Large age Catalog ~ Dogs and Pouliry free ri ‘or yours today. Edw - Souder Telford, Pa. ae FORMULAS AND TRADE SECRETS “TWENTIETH Century Book of This book Formulas and Processes’”— you the information that represents the ek lection of years and the expenditure gf thousands of dollars. Contains completed. rections for making everything from simpl glues and adhesives to the tanning of leathe, the making of photographic ma fumes, soaps, plating of silver and working of metals, etc. 800 Pages, 1 Selected Subjects. Price $3.00. Book partment, Popular Science Monthly, 2% West 39th Street, New York. 150 FORMULAS, including Luminoy Paint, Egg Substitute, Resilvering Mirrom, Renewing Dry Batteries, Gas Tonic, 25, Bestovall Laboratories, Box 543-PS, Chicago, HOME Pfoviders Attention! Butterd Fine for table use, baking Satisfying, Appetizing, Eco Oleomargarine. Guaranteed formula, Norman A. Ovri, Hemet, California. EVERYMAN’'S PLEDGE — America shall win this war! Therefore, I will work, I will save, I will sacrifice, I will endure, I will fight—cheerfully, and to my utmost— as if the whole issue of the struggle depended on me alone. POULTRY AND LIVE STOCK POULTRY Paper, up to date, tells all you want to know about care and management of ultry, for pleasure or profit; 50c per year, our months for 10 cents. Poultry Advo- cate, Dept. 146, Syracuse, N. YOU can turn your spare time into della by taking subscriptions from your acquaintances. You as a regular reader ot POPULAR SCIENCE MONTHLY, know its good ints and can a its attractive features nm a way which will readily secure & number of subscribers. Convince me that you are in earnest and willing to take at vantage of this opportunity, and I will gladly send you full particulars as to how t £0 about the work, and also special ap papers for your territory. Don't wait until your neighbor has’secured the appointment— write today. Circulation Director, Porulat SCIENCE MONTHLY, 225 West 39th Séreet, New York. 7 ii AibtasRleieins asaeaens bsdaleare one 2 Ka 4 ;

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Popular Science Monthly Answer This Call! Learn Draftsmanship Your country needs skilled draftsmen. The Ordnance Department of the Gov- ernment has issued anothercall; this time for 1800 trained draftsmen at big salaries. The manufac- turing industries are clamoring for more skilled draftsmen in all branches. Salaries paid compe- tent draftsmen, although high at the present time, are bound to go still higher. The serious scarcity of draftsmen is recognized in both gov- ernment and manufacturing circles, for drafts- manship is at the very foundation of all Engineer- ing,Construction and Manufacturing enterprises. Profit by this opportunity. Help your coun and yourself. Learn Draftsmanship. There will be a place for you at a good salary the very day you are qualified. Draftsmen in ordinary times earn $25.00 to $100.00 a week. What will this extra demand and the scarcity of competent men mean in the raising of salaries? And remember the nation and its great business organizations are calling now, ready topay the full worth of the trained men. Learn Quickly By Chicago “Tech” Methods The intensive training given by the Chicago Technical Col- lege brings quick results. Your instructors will be practical men now engaged in engineering work. They teach by ap- proved methods—Chicago “Tech’’ methods—demonstrated to be right by experience, No timcis putin on needless theories. Previous training or experience on your part is not neces- sary. You will get the bedrock principles and their practical application, Ina few months you will zain what would take years _< ong | ip, Sos — out raga yes at the end , finished draftsman—wi t term means to you in position and income. Study at Home ¥oa need not leave your present occupation to get this ex- os ning in Draftsmanship. We will teach you by mail you can study at home in your spare time. Same prac- work as you would have if you were a student in either When writing to Advertisers please mention Popular Science Monthly our Day or Evening Classes at the College here in Chicago. Pay for the course as you goalong. The fee is so small, the terms 50 easy that no matter how moderate your income may be, you can afford to get this training in Draftsmanship which will prepare you for an important paying position. Drawing Outfit Acomplete high gradedrawing outfit is included with you? course without extra expense to you. This includes all neces- sary tools just as used in the best modern drafting rooms. If you already possess such an outfit you will be allowed a cash credit for it. ~~ Send For Test Lesson This Free Test Lesson is an ab- solute test, pure and simple. Find out for yourself before you enroll, whether you are proper material for a success- ful draftsman. No charge for this Test Lesson either now or later. It is abso- lutely Free. Send for it today. Mail the coupon, marking it to indicate which branch of drafting especially interests you. Chicago Technical College 631 Chicago “Tech” Building Chicago, II. pmo TE Chicago Technical College 631 Chicago “Tech” Building, Chicago Without obiigation to me, please send me your FREE Test Lesson in Draftsmanship and other interesting literature cover- ing the subject indicated below. (Mark X opposite work in which you are specially interested.) O Architectural 7 ~afting OBuiiders’ Course OMachine Drafting OPlan Reading

OElectrical Drafting OEstimating OStructural Drafting OSurveying OSheet Metal Drafting OMap Drafting PURINE iiss ioene tee cdcobdscvabqcndivessiccaceteclwasen uanaaateennanie DMI i v6 ds évcntvressesees dvcevedchgersetunsensnansabeusteanianan CRAs ct ccnlcccocseucgdsvedevkscewonecieugden’ Gisidsiccucanscaauan

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STAMPS AND COINS STAMPS—338 fine foreign incl. Mex. War. Salvador, incl. Officials. Guatemala, China, etc., only 10c. Best App. Sheets 60 to 80% dis——100 diff. fine 10c. 1000 hinges 10. Big 120 page catalog free. We buy Stamps. Hussman Stamp Ce., St. Louis, Mo. 50 excellent’ stamps, 8c. Lists free. Edwin Bailey, Farmingdale, N. Y.

350 different stamps 35c. Lutheran Club, Box 176, Terre Haute, Indiana. Continued from Page 26 CALIFORNIA gold quarter size, 27c; hailf-dollar size, 53c; dollar size, $1.10. Large cent, 1818, and catalogue, 10c. Norman Shultz, King City, Missouri.

STAMPS 58 varieties, Transvaal, Brazil, Peru, Cuba, Mexico, Ceylon, etc., and Album 10c. 1000 Finely Mixed, 40c. 65 diff. U.S., 25c. 1000 hinges, 10c. List free. I buy stamps. C. Stegman, 5949 Cote Brilliante Ave., St..Louis, Mo.

FREE! United States stamp cataloging; 20c., with approvals. Riedell, Schenectady, New York.

OLD Coins. Large Spring Coin Cata- logue of coins for sale free. Catalogue quot- ing prices paid for coins, ten cents. William — 101 Tremont St., Dept. P, Boston, ass.

“QUICK-ACTION Advertising—How it is Building Business for the Progressive Advertisers of America.”’ A little story of Results, told by the advertisers themselves— not the publisher. You will be interested in reading the little booklet we have prepared, a copy of which will be gladly sent upon re- est. It may solve YOUR problem. D. qui + W. Coutlee, Classified Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. FREE, 60 different stamps including New- foundland, China, degen. Mexico, etc., to applicants for our high grade approvals. Send 3c stamp for return postage. The Edgewood Stamp Company, Dept. M, Milford, Conn. STAMPS. 61 All Different, 3 cents — paper. Quaker Stamp Co., Toledo 0.

$2 to $600 paid for hundreds of old coins dated before 1895. Send 10 cents at once for new illustrated coin value book. Size 4x7. It may mean your fortune. Clarke & Co., Coin Dealers, Box 76, LeRoy, N. Y.

TWO Uncirculated Villa copper coins 25c. Moore Coin Company, Commerce, Texas.

SELECTIONS sent on approval, 70% discount. Reference required. J. Emory Renall, Dept. M.; Hanover, Pennsylvania.

“QUALITYPLUS” approval applicants will receive set 8 varieties Nyassa, cata- logued at .43. McAndrews Stamp Company, Charleston, West Virginia.

PACKET “A” 100 varieties foreign stamps, 20c. F. J. Pope, Charlotte, Ver- mont. 15 JAPAN Free with trial Approvals. 1000 Hinges 5c. Frank Thorp, Norwich, New York, STAMP Paper and $l. Parcel-Post 15c. Weatherby, Medina, Ohio. STAMPS. Fifty all different U. S. and foreign for $1.00. Selling out collection. Bargain. E. Royal, Bryn Mawr Ave., Trentor, New Jersey.

ROYAL Approvals—at one and two cents each. Send reference and agree to return books in five days. Belmont Stamp Com- pany, 32S. b7th Street, Philadelphia, Pa.

FREE! Rare old, unusual Tasmania t9 approval applicants. Riedell, Schenectady, New York.

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YOU can turn your spare time into dollars by taking subscriptions from your friends and acquaintances. ‘You, as a regu- lar reader of ‘‘Popular Science Monthly,” know its good points and canpresent its attractive features in a way which will readily secure a large number of subscribers. Con- vince me that you are in earnest and willing to take advantage of this opportunity and I will gladly send you full particulars as to how to go about the work, and als» special ap- pointment papers for your territory. Don’t wait until your neighbor has secured the appointment—write oday Circulation Director, Popular Science Monthly, 239 Fourth Avenue, New York.

17 Varieties Hayti stamps 20c. List of 7000 varieties, low priced stamps free. Chambers Stamp Co., 111C, Nassau St., New York City. 28 When writing to Advertisers please mention Popular Science

105, China, etc., Stamp Dictionary, list 2c. Album, 500 illustrations, 3c. Bullard, Station AA, Boston.

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TRICKS, Puzzles, Jokes, Toys, Games, Novelties, Doll and Cane Racks, Plays, Wigs, Stage Supplies, Escapes and Illusions. Large 1917 catalog free. Oaks Magical Co., Dept. 491, Okshosh, Wis.

MAGIC—FEscapes—lIllusions—Catalog of Parlor Tricks Free. Professional Catalog with 500 Illustrations, 1000 Tricks, 10c. Second-hand apparatus bought or exchanged. Hornmann Magic Co., Sta. 17, 470 8th Ave., New York.

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MAGIC Tricks for pocket, parlor and stage. Thurston’s book pocket tricks 25c. Book card tricks 25c. Five different card tricks 50c. Send 3c stamp illustrated cata- logue. A. P. Felsman, 115S. State, Chicago.

BARGAIN Package—Puzzles, Tricks, Mystic Novelties and Catalogue, 25 cents, Company, Box 167, Watertown. Connecticut.

MALTESE Checkers—Something Differ- ent, interesting, absorbing. Complete game and instructions, 25 cents. Allied Games Company, 1404 W. Franklin Street, Balti- more, Maryland.

BOOKS AND PERIODICALS

BROOKES’ Automobile Hand-Book— poet size, 720 pages, 329 illustrations, full imp leather covers, price $2.00. The perusal of this book for a few minutes when trouble occurs, will not only save time, money and worry, but will give greater con- fidence in the car with regard to its going qualities on the road, when properly and intelligently cared for. Satisfaction or money refunded. Criterion Service, West New York, New Jersey.

GREAT Sensational Story—Genevieve de Brabant, $1.00. The Mysterious Hindoo Mystic, 25c. Sovereign Publishing Company, 160 Sycamore, Buffalo, New York.

“PRACTICAL Armature Magnet Wind- ing’’-—This book treats in a practical and concise manner this very important subject. All practical armature windings are fully ex- plained with special attention paid to details. All questions which are apt to arise in the mind of the electrician have been completely answered. This book will prove a most valuable aid to the electrician, either in the constructing or operating department. Full Persian Morocco Leather, Pocket Size. Price $1.50. Book Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York.

USED _ Books. Bargains. Catalog. Higenes K-2441 Post, San Francisco. (Books Bought.)

“HANDY Electrical Dictionary’’—Con- tains upward of 4,800 words, terms and phrases employed in the electrical profession, with their definitions given in the most con- cise, lucid and comprehensive manner. Although the book is small enough to fit in the vest pocket, we venture the assertion that there is contained within its covers more reliable and useful information for the electrician, than was ever before published in a single volume. Cloth, Red Edges, In- dexed. Price 25 cents. Full leather, Gold Edges, Indexed. Price 50 cents, Book Department, Popular Science Monthly, 225 West 39th Street, New York.

on TAL Wireless § eir Theory, Design, Const; oe by wien | <4 Fdleman. Coma o complete account of sharp] wireless installations for od a modern quenched spark system. T tended for experimenters whee book of wireless as more than a mere and who will find it a stepping stone serious preparation for high positions tae practical field. Written with particular gard to clearness, simplicity and direct : ness, this book should be of exceptional to the amateur as well as the more advan worker. Contains 219 pages, 30 illustra. —_. —_ goon Book Department, opular Science Monthly, 22 Thirty ninth Street, New York. hes WORLD-ROMIC Syste n M = all languages. Six text books, $i4e we 4 chart. 37c.; Spanish, 37c.; Aviation diction. ary, $1.50. Languages, 143 West 47th;

New York. “SPANISH-IN-A-WEEK,” by T. g§ Romero. The best text-book to the great language of Latin-America. Embod new method, scientific, exact, comprehi

a by an expert teacher of pure ‘lliag Spanish. This book contains the clement of. the language, easily grasped and of sufficient vocabulary to enable anyone to obtain working knowledge of Spanish. Every word phonetically pronounced. Widely used by export houses, engineers, salesmen, Student; teachers and travelers. Price 50 cents, Book Department, Popular Science Monthly, 225 West 39th Street. New York. 5 “PHOTOGRAPHY Self-Taught.” Comes plete instructions on how to operate the camera, develop the plate or film, print ang finish the picture. Paper 25; cloth 50, (No Stamps.) _ Criterion Service, Dept, 1. West New York, New Jersey. 45% “TWENTIETH CENTURY BOOK oF RECIPES, FORMULAS AND PROC ES”—This book gives you the information that represents the collection of years and the expenditure of thousands of dollars. Con- tains complete directions of making every. thing from simple glues and adhesive to the tanning of leather, the making of photo graphic materials, perfumes, soaps, plating of silver and gold, working of metal, ete, 800 Pages, 10,000 Selected Subjects. Price $3.00. Book Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. K “$500 Yearly Profit with Twelve Hens.” Complete instruction in book form pF expert on Gallino-Culture. Price 25c. Cloth 50c (coin). Criterion Service, Dept. 1, West New York, New Jersey. “MODERN Electrical Construction”—Ig a perfect guide for the beginner and gives all the theory needed in practical work in add- tion to full practical instructions. For the toni Age electrician it is no less valuable, ecause it elaborates and explains safety rules in vogue throughout the United States. It is also of value to electrical inspectors, ag it points out many of the tricks practiced unscrupulous rsons in the_ trade. Pages, 173 _ illustrations. Price, $1.50. Book Department, Popular Science Monthly, 225 West Thirty-ninth Street, New York. READERS of Popular Science gm here’s your chance: We have on hand copies of bound volumes No. 88—January to June 1916; 25 copies of volume No. 8$— July to December 1916; 25 copies volume No. 90—January to June 1917 and 500 copies of volume No. 91—July to December 1917. These copies are beautifully bound in heavy gray covers with drk green bac! containing the words ‘Popular Selience Monthly,” the volume number and months included. Each volume com pages, 1,306 articles and 2,08: Just the thing for your library. A ten page index enables you to find in a moment any article or picture desired. Contain no ad- vertising whatever. At the present cost of printed matter, these columes should retall at $5.00. You can secure them now for $2.00 each, postpaid. Classified De ment, Popular Science Monthly, 225 West Thirty-ninth Street, New York City. NT “QUICK-ACTION Advertising—How it is Building Business for the Pr Advertisers of America.” A little story of Results, told by the advertisers themselves— not the publisher. You will be interested ia reading the little booklet we have prepared, & copy of which will be gladly sent upon Tre uest. It may solve YOUR problem. D. . Coutlee, Classified Department, Science Monthly, 225 West Thirty-ninth Street, New York.

paprctecoe =

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EER,

Popular Science Monthly

instruction. purposes for stu Come to Detroit The Automobile 12 weeks.

arvester Company of America International H ee on Harvesters and Other Lines of Machinery Harvester Building CHICAGO, November 20, 1917. ZELLER, President, . ee az hicSican State Auto School, Detroit, Michigan. R. 3 ee careful examination of your school, we are satished that it will be a very wise thing for us to co- operate with you. We are therefore placing in your hands, for instruction purposes, one of our Titan 10-20 tractors ther with = engine completely equipped mplete transmission. tee pack Sage ard with you in the excellent work you are doing by giving your school all the data and information not only on tractors, but on conditions gen- erally that can be used in developing thoroughly practi- tors an ‘ ey od copy aoe rating with the factories is very commendable, for it brings together the biggest men and most successful ideas to he hid. As you know, there is an urgent demand for tractor men who are trained and efficient. War has taken thousands of men from the farms and these men will have to be replac and more needed to care for the big crop increases. We will gladly co-operate with the Michigan State Auto School through our ninety branches in the United States in placing your tractor graduates. ere is a constant demand for competent trained tractor men at very good wages. Very truly yours, INTERNATIONAL HARVESTER COMPANY OF AMERICA Signed by F. W. Heiskell, Advertising Manager.

Auto Factories Endorse dorse our school. latest model complete chasses in our school, employ our graduates and assist em garages and salesrooms. course. They are holding good courteous treatment hool The leading Auto Factories en- They put their in opening Women Take Course Many ladies have taken our itions and are completely satis- ed with our instructions and the accorded tity of aeroplane material. and secure complete knowledge of the ptane in general. The course is under direct super-

We guarantee to qualify you for a position as chauf- feur, repair man, tester, demonstrator, auto electri- clan, garage man, automo- bile dealer, Aeroplane mo- tor mechanic or tractor me- chanic and operator, paying

our graduates. Detroit. 71% of Earn $75 to $300 a any time, any day. Three classes daily; morning, afternoon, evening. quickly. give what Detroit does. what it means to learn inthe M.S. A.S. Factories endorse our school, glad to employ ; Men are needed everywhere as testers, re- pair men, chauffeurs, garage men and salesmen. of our graduates start in business for themselves. We teach you to handle any auto proposition. You graduate in from 10 to Equipment is new, up-to-the-minute, complete. motors, or chasses used. Students actually build cars, assembling, block-testing, road-testing, everything. Acetylene brazing, welding and cutting, also Tire Repairing separate from regular course. Learn to time motors, rebore cylinders, adjust bearings and carburetors quickly and accurately. Six-cylinder Lozier, Chalmers ‘‘6”’, Detroiter “*6’’, Overland and 8-cylinder King are used for road We have 25 motors in block test department. having every standard starting, lighting and ignition system. Detroit is the Place to Learn—Start Any Time 44 Auto factories in Detroit and vicinity and 144 accessories and parts factories. perience in handling all kinds of auto equipment. , getting factory training in Special complete course in Oxy- Our electrical department is complete, f Students get actual ex- We have Sprague Electric Dynamometer for block-testing dents’ use. Ours is the only Auto School having this equipment. School open all year. Enter classes 29 DETROIT trained men get preference and jobs No other city can Think Automobiles made in Hundreds Month No old, obsolete

Complete Tractor Instructions Added to Auto Course Our Automobile Course has always included all the in- structions necessary to handle Tractors. By adding I. H. C. Titan 10-20 com- plete tractor for actual working con- ditions and a com- plete engine and transmission for the block test depart-

ment we are train- ing our students in the care, repair and operation of the Tractor. The Oliver Chilled Plow Works of South Bend, Ind., placed their No. 78 automatic lift three bottom tractor plow in our school for student work. When students leave our school they are trained in every branch of work and can repair, maintain and operate Automobiles, Trucks and Tractors. Get your training in the original school.

GET INTO THIS NEW INDUSTRY NOW <=: them. nautical Motor for practice and study. We have a complete plane and a quan- Students get practical instruction on the Aeroplane Motor vision of an experienced aeroplane man who is an authority on aero-motors and aeroplanes. Money-Back The men who become trained Aeroplane Mechanics now will be the big men in the aero- uarantee plane business. The far sighted keen fellows who enter at once will reap the big benefits.

Act Quickly—NOW! Get literature on Aeroplane Motor Mechanics, Auto and Tractor Course. Tire Repairing, Brazing and Welding, “Auto Schoo! News” and New 176-Page Illustrated Catalog. All absolutely free. Or better still, jump on the train, as hundreds have done, and come to the ‘Heart of the Automo- bile Industry,’ and learn right. We have no branches, Write orcome direct to this school. A REFUND WILL BE GIVEN TO STUDENTS CALLED TO THE ARMY MICHIGAN STATE AUTO SCHOOL from $75 to $300 monthly The Old Reliable Schoo! or refund your money. 586 Auto Building, 687-89-91 Woodward Ave., Detroit, Mich., U.S. A. A. G. Zeller, President

Not a One Man School This school is founded on the st, most practical and new- est principles in the Automo- bile, Aeroplane and Tractor business. It is the result of the keenest co-operation with manufacturers, service sta- tions, garages and owners. It is not one man’s idea but the ideas of the biggest, best and most successful men in each field. A. G. Zeller, Pres.

DETROIT THE HEART OF THE AUTO INDUSTRY

When writing to Advertisers please mention Popular Science Monthly

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These are the Hours That Count byes of your time is mortgaged to work, meals and sleep. But the hours after supper are yours. You can fritter them away on profitless pleasure, or you can make those hours bring you ~aenmages money, power, real success in life. ere is a big job waiting for you—in your a work or any line you choose. Get ready rit! You can do it, through the International Correspondence Schools, without losing a minute from work or a wink of sleep, without hurrying a single meal and with plenty of time left for recreation. Make Your Start Now Everything has been made easy for you; one hour a day spent with the I. C. S. in the quiet of your own home will bring you a bigger income, more comforts, more pleasures, all that success means. Can you afford to let another sin- gle priceless hour of spare time go to waste? Make your startright now! This is all we ask: Without cost, with- out obligating yourself in any way, put it up to us to prove how we can help you— Just Mark “me Mail This Coupon f= aan a= =— a= CeETEAR OUT HERE® aoe aoe aeee oe oes = [INTERNATIONAL CORRESPONDENCE SCHOOLS 882 Scranton, Pa. Explain fully —, oe Course in the subject marked X: SALESMANSHIP ADVERTISING Window Trimmer Railroad Trainman Illustrating BOOKKEEPER Poambamatenstenc? 3a + ool ve Roam | : a i=) > e ise} iw 2 = z bs] iso] = e Operating Railway Accountant IVIL ENGINEER AGER rveying and Mapping Commercial Law INE FOREMAN OR ENGINEER GOOD ENGLISH TATIONARY ENGINEER CIVIL SERVICE Railway Mail Clerk a and Builder AUTOMOBILE OPERATING Auto Repairing SPANISH — silder |Mathematics erman PLUMBING AND ‘BEATING AGRICULTURE French |Poultry Raising Italian Name. Address Se et Ae eee ee Popular Science M onthly BetterYour. Position $125-$250 a Month Are you_under 55? War has taken the youth of the country. Railroads demand Traffic Inspecto: young men or old men, but trained men. $1254 month and expenses to start. A business of Protection—he sees that regulations i served—he is an efficiency man. An interes travel is his if he wants it. He is in a pcsition to erp opportunities. If he is efficient he is noe positions of trust. Hundreds bea now. no excuse for failure today. This is your cae You can do this with proper training. i. qualifies you in3 months’ home study, an for position. Write for oxplanalecyh Ee, Fronti fier Propavatsry’ School BUFFALO, This Interesting Free Book shows how you can become a skilled player of piano or organ in your own home, at ong quarter usual cost. Dr. Quinn’s Written Method i is conned by leading musicians and heads of State Com servatories. Successful 25 years. Play chords at once and complete Dieoe in every key, within 4 lessons. Scientific yet easy to understand, illustrated. For —— or teachers, old or young. All music free, Dj. ploma granted. Write today for 64-page free book, ““How to Study Music” M.L. QUINN CONSERVATORY. Studio ZF. Social Union Bidg., Boston, Mas, COPY THIS SKETCH ae ~~ suly and let’s see what you can do withit. Car-. sal toonists and illustrators earn from $20.00 to $125.00 or more per week. My practical system of personal individual lessons by mail will develop your talent Fifteen years’ successful work for newspapers and maga- zines qualifies me to teach you. Send sketch of Uncle Sam with 6c in stamps for test lesson plate; also collection of drawings showing possibilities for YOU. State your age. The Landon School (esate 1451 Schofield Bldg., Cleveland, O,. LEARN AT HOME SHORTHAND oa¥s keauint DAYS REQUIRED Detroiter invents and perfects the most wonderful system in existence. Holds world’s record. Guaranteed. Easiest to learn. Money refunded if you fail. Quickest to master of any method known. Hundreds of Graduates now earning big money in employ of Government, Offices, Banks, a etc. Demand enormous. Write quick for FREE illus catalog. Proofs of success, Guarantee and Special Offer. GARVIN INSTITUTE 253;735.4outarg,! EARN TELEGRAPH Morse and Wireless—R. R. Accounting (Station Agency) also taught. a Demand — much greater than supply—Permanen ¢ Coorene Secured. Big Sala rlee—re- cently raised. ideal W orn Conditions—short hours, vaca- tions with pay — = leath benents, eee rare ling. cement. also aise seene y desired aby Railways and Western Union. Tuition mable. Cheap living expense s—can be earned. Oldest and | largest school—two large school buildings, investment ceed: 000. 00—established 43 years. indorsed by railway, Western Union and Marconi Telegraph officials. large illus- trated maloess | free. waa eemeames courses also, Write Dodge’ ote egraph, Ry. Ry. & \ Wireless Institute Never has the demand been greater—or advancement more ry — . Weare receiving. poe requests for an we Ci Ean $2500 to $10000 om A e pense gerned over #100 in one day ’ from $800 Clerk to $6500 Salesman noon rose from 00.8 month Salesman. Hundreds of other amazing Bodine! can t us show you ho’ Learn Salesmanchip in in spare time---Earn while you learn, J F ri fa does Amazi Salesmanship Book. Tell F be E E! t ototy couree=-quotes letters # frome Members eerie yment service. Proves pro’ fitsin travelling ship. We will also =r ma t of positions open. Write ‘Now. est office. Dept. NATIONAL “SALESMEN’S TRAINING po Chicago San Francisco New York When writing to Advertisers please mention Popular Science Monthly Beate ReNaeed Ns a dares Sea 5

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Popular Science Monthly From. i Mechanic 2 ‘ro ' Aeroplane Inspector Pay Dou Mr. Frank W. Potts, formerly with the Ford Auto- mobile Company, wrote us the other day as follows: MR. JOHN A. TENNEY, President, National Aero Institute, Chicago,-Ill. Detroit, Mich. Dear Mr. Tenney: Today I have entered the employ of the Packard Motor Car Company to work in the Experimental Aircraft Department. I had my first big opportunity to see and look over the wonderful Liberty Motor. I am only too glad to say that I owe this wonderful opportunity to the National Aero Institute and to my study of your great Course. 't was through your influence with the Packard people and the fact that I was thoroughly interested in aeronautics that was able to get this position. I feel that I am on the road to a genuine success, and I owe it all to the National Aero Institute, Am sending under separate cover the enro!lment of a new student. Sincerely yours, FRANK W. POTTS. J Send Coupon for FREE BOOK e If | a If | fw & Just write your name and address in the coupon and send k, “THE SCIENCE OF it_to us. e wilt send you our free boo P AVIATION,” and our Special Limlted Offer on our complete Mail The U $ Government plans to send Course. This book will teli you of the many big opportunities you 4 M4 = will have in this great new industry. Tear out thousands of men to Europe who will be compe- the coupon and mail it today. DO IT NOW! tent to keep its great airplane fleet in good NATIONAL AERO INSTITUTE working order—a great mechanical army which will be as Dept. 1208, Morton Building, Chicago, Illinois important in its way as any other branch of the service. ee A ERE ER GS Oe We Teach You Aviation by Mail at Home National Aero Institute, Dept. 1206, Morten Bidg., Chicago, If. Gentlemen: Please send me, absoiutely free and prepaid. ° : ee ° your new the Science of Aviation; also Study in spare time. Your training wil! be under the direction of experts— men who have great reputa- tions in the field of aeronautics. on cu f Mail Course in the Principles of Aviation and spe- cial limited offer. Name Address Brookes Automobile Handbook Check the Job You Want! practical instruction book covering | :--iziad Maeda |. sokeen tone eae every feature of all motor cars. Re- | °1! ‘Postofice Carrier $800 to $1200. Stenographer $1200 to $1500 vised by H. P. Manly. 720 pages, | ....Rural Mail Carrier $600 to $1200... .Clerk at Washington $1100 to $1500 fully illustrated. Bound in limp leatherette, gold stamping. Pocket size. Sent prepaid for....... $2.00 Send for our large catalogue show- ing over 150 books for Electricians, Wireless Operators, Automobilists, Engineers, Railroad Men, Machine 1918 Edition PUMITRO S66. 0:0:sie-0'0 Xcinraclé es onesie ee cee eemee cosas ot eene aaa RAOUOEEE i cinecvciestendvcwssetcdcadipeds @eescesee***eeee Sign your name and address and send us this coupon immediately. We will immediately send you (1) a full description of the position checked, (2) a list of : Shop Men, Carpenters, Builders, many U. S. Gov't Jobs now open and directions telling how Sign and Scene Painters, etc. It is FREE. to get free coaching for the position checked. FREDERICK J. DRAKE & CO., 1003 Michigan Ave., Chicago | Franklin Institute, Dept. P111, Rochester, N. Y. Complete $15.00 Set of Dr ing Inst t YES. I will give you this exquisite set of imported drawing instruments absolutely free and I will give you a 20 x 25 inch drawing board, a 24-inch T square, a 12-inch rule, a supply of drawing paper, 2 triangles and a French curve, pencils, erasers, thumb tacks, etc. The instruments come in a superb plush lined leather case—they are genuine es working instruments and | don’t think you could duplicate this outfit for less than $15. But 1 give it away absolutely free to the men who get my personal instruction. Draw $125 to $175 Per Month men® Gompunice are inentee nied, ratte, for men to fill positions paying from $125.00 to $175.00 per month. I will give you just the training you need to hold one of these big jobs—right in your own home. Write now. dC ar. en ou p on 7 Chief Draughtsman Dobe for Big New Book 7 yi 'tiso” Giicare. Tl v. 4-120. Chicago, Hil. Write me personally for my new Without any obligations on me whatsoever, book on drafting—sent free. 7 please mail your book ‘‘Successful Drafts- Send the coupon now. **Personal Instruction’’ offer to a few students. Chief Draftsman Dobe 7 tin anderatood that I am obligated in no way er, Engineers Equipment Co., Inc. Div. A-120 7 PRAURE ........... 2.02. secececccceecececoccscscescovwcseserssncsesens Chicago, um. 7 Pt Re IRAE St S| When writing to Advertisers please mention Popular Science Monchly manship’’ and full particulars of your liberal

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anode Scrence Monthly This valuable book Motor Car Laws —is the only one of its kind ever published. It gives you all speed and light regulations, licenses, fees, registrations, how automo- biles are taxed, traffic rules and authorized road signals of United States and Canada. tes auto: owner, garageman, repairman and chauffeur needs a copy of this interesting book. mobile Let Us Mail You a Copy Free If you will send us only 25c. in stamps or coin for a three months trial subscription to America’s greatest il ile magazine, we will send you a copy of this indispensable book ‘‘Motor Car Laws” postpaid ABSOLUTELY automob FREE with your trial subscription. AMERICAN CHAUFFEUR ~~ 126 Butler Bldg. An “AUTOMOBILE DIGEST" Cincinnati, Ohio., U.S, A, Build Your Own PHONOGRAPH _ STUDY ATR it’s Easy With Our Help mates arene A few hours interesting work saves usiness and public life many dollars and gives you a ma& portunities rd ine exactly to suit your ideals. $3, p. s1esen ish motors, tone arms, case RR Wesuide we Ae blue prints and full in- yy at at home durin structions. Playsany record. You . fanden can make fine profit building phon- ¢ Tod | Sed Daerecet’ ographs for your friends. r dents enrolled ibrary and Get our ble 1 e free. Send for then NOW. LaSalle Extension University, He peat Write Today for Our Free Blue Print Offer CHORALEON CO. “Handy Electrical Dictionary Contains upward of 4,800 words, terms and phrases em Learn ‘ in the electrical profession, with their definitions riven in the by Cod oF. be bl er Aviation concise, lucid and comprehensive manner. Although the Mechanics is small enough to fit in the vest pocket, we venture the needed for New that there is contained within its covers more reliable and Positions. Write to- information for the electrician, than was ever before nc Con eee Find out about the asingle volume. Full Leather, Gold Edges, Indexed. Price 50 ng opportunities in Popular Science Monthly, 225 W. 39th Street, New York Gy the Sirplaneindostry. Govern- . 3 ment also needs thousands of men, country. We @ new corr course in practical aeronautics and principles ~y aero- nautical construction and engineerin Write at once. Limited number of reduced een vi Se ese now available. American School of Aviation, Dept.120 So. Dearborn St.. Chicago FREE 79 Lessons In Public Speakin nary offer. 10 lessons jn public speak- spare tat free, open eyeome "stage fright," enlarge your vocubulagy: train your memory if-confidence ularity. We bave = bundreds. ‘Practical Armature and Magnet Winding” This book treats in a practical and con- cise manner this very important subject. All Off. ited Tisotfer le made strictly for advertising practical armature windings are fully ex- m Offer Lim @foteen iereen elles tenke. be, withdrawn at any tm now. plained with special attention paid to details, North American Institute, 1206 Manhattan Bldg., Chicago, III. All questions which are apt to arise in the mind of the electrician have been completely 3 answered. This book will prove a most valua- ble aid to the electrician, either in the con- - structing or operating department. Full Persian Morocco Leather, Pocket Size, W Price, $1.50. ve sO “20th Century Book of Recipes, Formulas and Processes” This book gives you the information that represents the collection of years and the ex- Ss ; penditure of thousands of dollars. Contains : BECOME. A complete directions for making everything “ FIC MANAG from simple glues and adhesives to the tan- B = __Oer half a million ar shiopers and all ning of leather, the making of photographic rail roads need trained Tratve Men, those who know materials, perfumes, soaps, plating of silver ™ . cure quishast deliveries, classify guods, obtain fowest and gold, working of metals, etc. 800 Pages, B Bi Everywhere there are big positions and. 10,000 Subjects. Price, $3.00. sa Salaries For Trained Men ; make ope rears Opers hearty Popular Science Monthy qui ats cost—eas’ ‘men e . + A aan, “tees 225 West Thirty-Ninth Street, New seTbe World’s Greatest Extension University’’ Se When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly 38 s "IN FOUR = MONTHS This is Richard A. Oldham Mr. Oldham was telegraph operator for the Illi- % nois Central Railroad for twenty years. He is fifty-eight yéars old. One day he read one of my advertisements and the possibilities of making money in the Auto Tire Repair Business. Ina few weeks, he had purchased and installed a Haywood outfit, and was doing business for himself. A short time ago he wrote us that his income in four months was as much as it had been in Two and One-Half vears as Telegraph cg wok A ig are thirty — ee use every day—ounctures and blow outs are co"n- : mon. mething going wrong all the time. ew tires advancing to prohibitive prices. Owners forced to have their old tires fixed. I have 500 other places to be filled now. “G0 Be ee o M. HAYWOOD, Pres. I Must Have 500 Men y Haywood Tire & Equipment Co, to fill these places within the next 60 days @ Tiiainapotte, tnd.” ‘ Dear S1R:—Please send me_ your Ihave a big interesting book to send you—a bonk about tires—it tells all about them—how they ¢ ; . i i are repaired by the Haywood method—explains this business—gives inside figures. and profit Se re ae Plante r and full particulars on your National Gives actual proof of success. What these men have done you can do. $2500 to $4000 a vear ? Tire Repair Service and details of yous is conservative. One machine will give you astart All you do is onen a shop—put out a e FREE school of tire repairing. Haywood sign, and auto owners will come to you. There is a big opportunity awaiting you. Sign the coupon and mail it today. or send a post card or letter. 4 een ee Eh m.navwooD, HAYWOOD TIRE & EQUIPMENT CO. 724 ,Gan!to!, avenue, Do YOU Know —Our 3% Spanish war bonds after the war sold at 11214% —Life insurance companies have over $800,000,000 invested in farm mortgages? —How To Invest Through Partial Payments? —About different kinds of bonds? Whether or not you are an experienced in- vestor you will find it worth while to read some of the booklets in The Scribner Pocket Investment Series Select those you want from the titles follow- ing—sent without cost: “How to Invest”— “Bonds and The Investor’—‘‘Our Foreign Bond Holdings’—‘‘Partial Payment Invest- ments’—Investment Position of Municipal Bonds”—“The Farmer Must Be Financed” —“The Farm Mortgage as an Investment.” ui ARTIST CHECK FROM MAGAZINE o— > DRAWN BY 14-YEAR-OLD BOY The above cartoon was drawn by Master Bob Brennan of txe Washing- ton School of Art. Bob writes that he is selling his work and that he is cartoonist on a small paper in Evansville Ind. He is but one of our many students and graduates who are making money as cartoonists, illustrators and designers. Learn By Mail at Home! By our new method of teaching crewing by mail you -an learn in your own home, in a short time. Get into this fascinating work yourself and earn $50 to $100 or more per week: P The study is fascinating Only afew minutes aday! Have your own studio or secure high-salaried position. Or work tn spare time. Many students earn while they are learning. FREE BOOK AND ARTISTS’ * OUTFIT! WRITE TODAY A complete Outfit free to all students. Inctudes everything required to produce hundreds of dollars’ worth of pictures. Write today. Special terms to a limited number of new stvdents Mai’ postal or letter for beautiful Booklet, ‘‘How to Become «n Artist." filled wth drawings and full particulars of our extraordinary offer, Do it now—before you forget. WASHINGTON SCHOOL OF ART, Inc. 1116 H Street, N. W., Washington, D.C. Investor’s Service Bureau SCRIBNER’S MAGAZINE 590 Fifth Avenue New York When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly “Pl Tell You What’s Holding YOU . ' \ Down, Jim— “You say that you’ve been with us several years and ought to have more money—that others have advanced while you stood still. “There’s a reason for everything, Jim, and in your case here it is: You’ve been short on headwork in your present job, and you haven't studied the job ahead of you at all. “When promotions have to be made, we give the positions to the men who are ready for them. Williams, you will remember, took a course of training with the International Correspondence Schools— that’s one reason why he’s a branch Manager now and making three times what you do. =m TEAR OUT HERE aoe eee oo INTERNATIONA RRESPONDENGE SCHOOLS “Your advancement is largely up to 0 BOX P. | L CORRES POnDEN A. you, Jim. We liketo keep our men, dion, or in the subject bere whine mack ey for the pest and to promote them, and we'll gladly ' ! ELECTRICAL ENGINEER i; i j Elecerc Ligh SALESMANSHIF take an interest in you when you think Electric Wing Show Card Writs } enough of yourself to get ready fora Telepheae Woe Ralroed Iesinman J better job. = MECHANICAL ENGINEER ILLUSTRATING } \ ey ey ed seooning ! » , - [Ges Eogine Operating a j There are lots of “Jims” in the world— OIVIL ENGINEER Cert. Public Accountant . : » Surveying and Mapping TRAFFIG MANAGER + In stores, factories, offices, everywhere. Are Metallurgist or Prospector Commercial Law } you one of them? Wake up! Every time Marine Engineer Teacher ae + you see an I. C. S. coupon your chance is : Contractor and Builder Mathematics Sublets =| staring you in the face. Don’t turn it down. Goneen Balser Rallway Mail Gle : ' Structural Engineer AUTOMOBILE OFERATIAG . Right now over one hundred thousand Sheet Metal Worker Navigation. A) German } men are preparing themselves for bigger jobs ¢ erecer or Supt AGRIOULTURE French CHEMIST Poultry Raising §CJitailam 1 and better pay through I. C. S. Courses. ) 7 ‘Name J pie ‘ : , + tei ' You can join them and get in line for P 1 promotion. No cost to find out how; jus and No mark and mail this coupon, City, State em Sr When writing to Advertisers please mention Popular Science Monthly

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American Library Association ° ° Library War Service GENERAL DIRECTOR ASSISTANTS TO THE DIRECTOR HERBERT PUTNAM CARL H. MiLam RIBRARIAN OF CONGRESS JOSEPH L. WHEELER EXECUTIVE SECRETARY HEADQUARTERS = Geonce B. UTLEY THE LIBRARY OF CONGRESS Crepuncine Orreae WILLIAM L. Brown WASHINGTON. D C March 18, 1918 Editor , "Popular Science Monthly” : 239 Fourth Avenue H New York, N. Y. tin } Dear Sir: We are just in receipt of a communication signed by the Cam p Librarians at Camps MacArthur, Logan, Bowie, Travis, Pike, and Doniphan, stating that there is in these camps a demand for "Popular Science Monthly", which is far in excess of the copies received through the Burleson “one- cent" privilege. It is very desirable that more copies of “Popular Science Mamthly” reach them promptly fran the original subscribers, On behalf of the thousands of reading men whom they represent, they ask us “in some emphatic way " to place this mtter before your subscribers and see if it is possible to get more copies of this magazine into the postof fice under the Burleson Act. The need is urgent. There is an over-suyply of some megazines, but an under-supply of yours. We are of the opinion that this need of a mipply exists at many other camps, and we therefore hasten te call this mtter to your attention. Very = yours, Random rh, The Cr tor Qotwee Mowtly ‘- We eet Reet ach ow his oll Kh Cant CTaoat ety Thr Comp Sibramiows B wroden AP Loner ~ * mnt Wats” TU Gish dilienn ox ch, enim hot TRL Wiontak nate obhice or mol doe. Cantene of th Crpulor Seaman Moti.

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Salvaging Ships Sunk by Submarines AIR COMPRESSOR <€-FLEXIBLE AIR-TUBE “BUOYANT MIXTURE. “FROM PUMP — ae

MIXTURE DISCHARGE ee

OUTLET.

Raising a Hull by Pumping a Buoyant Mixture Into It Salvage ships on the surface and section of sunken ship of usual cargo-carrying type below. Connection is made, extending.through all three.-hatchways of the ship to its hold, by a flexible tube secured within another flexible tube and continued within a metal pipe coupled to the latter. The metal pipe is secured toa temporary hatch-cover, with manhole for the up- per hatchway, and carries a ladder and working plat- forms for divers. The entire construction is further reinforced by brace rods wherever they are needed The inner flexible tube is connected with a centrif- ugal pump in the salvage ship. A derrick supports the tubing. A suction pipe with a cut-off valve or seacock leads from the centrifugal pump to the open sea. It connects with a hopper that receives the buoyant material. The paraffin comes through a pipe from the paraffin tank where it is kept liquid and heated by a steam coil connected with the ship’s boiler. An air pump is connected by a pipe toa space between the outer and the inner flexible tubing

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Vol. 92 No. 6 Popular Science Monthly 225 West Thirty-ninth Street, New York City June, 1918 $1.50 Annually —_—— pomroerasr Raising a Sunken Ship with Cork A way of salving valuable ships which have been _ torpedoed By Simon Lake thousand ships, ranging in displace- ment from a few tons to thousands of tons, have been sunk by submarines, mines or shell fire. The loss of the ships and of their valuable cargoes is so great that it is keenly felt by the nations princi- pally concerned. Long G thou: the outbreak of the war several take its place. Then if they are at any considerable depth the water pressure will crush in their decks. To place chains under the ship and attach them to pon- toons, from which the water is thereafter . pumped out, is a ticklish job unless the waters are quiet and the sea bottom sandy. The use of before the German sub- marine adopted the present policy of sink- ing all ships found within prescribed zones and thereby involving the United States in the war, I invented a method of salving ves- sels which may be ap- plied after the treaty of peace is signed. “Many of the ships sent to the bottom by the Germans are lost beyond all hope of re- covery. They: have been either too severely damaged by the explo- sions of mines or torpe- does, or they lie at depths too great to be reached by divers. But enough have found a resting place in water shal- low enough to justify the use of the inven- tion I am about to describe. I do not believe strongly in pumping water out of a sunken ship, because it is nearly impossible to close all openings and prevent other water from running in to Mr. Simon Lake, the author of this article, is one of the pioneers in the development of the submarine. His ~ reputation as an inventor and build- er of submarines and his vast expe- rience as an adviser on submarine questions to the United States Gov- ernment as well as to the leading European Powers entitle the inge- nious suggestions contained in this article to most careful consideration 803 many small air bags or casks placed under the decks by divers is costly and suitable only for small wooden ves- sels. I suggest that the water be driven from the interior of the ship by forcing buoyant ma- terial in, which may be accomplished by cen- trifugal pumps pumping into the sunken vessel water mixed with cork or heated paraffin or both. The buoyan- cy of these materials eventually lifts the ves- sel, and the materials are gathered and used over again. As paraf- fin hardens when cooled, it does not escape through small rents or fissures in the decks; on the contrary, it tends to close them. Holes in the bottom of the ship do not interfere with this process. The buoyant materials, after being forced in, tend to spread in a gradually hardening and ex- panding layer under the decks, strengthen-

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804 Popular Science Monthly ing and preventing them from collapsing or lifting. If weakness is suspected or reported by the divers, a mixture of paraffin and small blocks-of cork is- used in preference to either of the materials alone, as it forms a stronger and more binding mass, extending as a beam from one side of the ship to the other. After the upper decks have been sealed in this manner, air can be pumped into the vessel to force more water out, either through a pipe provided for this purpose or through breaks in the bottom. In the case of torpedoed ships with large openings in the sides, considerable pre- liminary repair work by divers may be necessary to close the upper portions of the rents or to con- struct bulkheads extending far enough down. The operation is readily understood by ‘reference to the: description under the accompanying illustra- into the hopper with the cork. To pyre. vent it from cooling and hardening to soon, air is pumped into the space between the inner and the outer tubing. Some air is allowed to be forced into the holq together with the cork and paraffin ang helps to carry these substances toward leaks and sealing them. Lighting Up East India—How America Helps NDIA is making slow but steady progress jn introducing more mod- ern lighting methods. Al] public lighting in the large cities of India is by elec. tricity ; but in smaller cities the methods of lighting, public as well as private, are still very primitive, The use of illuminating gas is extremely restricted and lamps in which pe. troleum or vegetable oils tion. When the seacock How Decks and Hatches are burned are used to is opened, water rises in Are Secured some extent, though not the hopper to the level of The upper deck of a sunken generally. ship may be strengthened by ° ° the sea. When now the hardened deposits of cork and For native festivals— 2 4 par nm unger it. o secure centrifugal pump is started cmp eed on g Free Rnigerag and there are a great many it pumps water into. the weighted and lowered into the of -these—large kerosene hold and placed in position by sunken vessel. If there divers. | Next the weights are lamps of an elaborate pat- nN i = removed and the buoyancy o are no holes in it, an out ae teeaen alls ame ts aol tern are much used. They let for the surplus water is tion. Bolts are lowered and are known in many locali- ° connected with the beams. ° cc supplied by means of a Then a second set of beams is ties as ‘‘Washington 4 H ; iT) placed on top of the hatch an ; ” 101 pipe raised in the ship’s Sead a ae echoes, Lights” and were original- bottom. The buoyant This arrangement effectually ly brought to India from ° 1s) utes the s on any one ° material—small blocks of deck to ail the deci of the ship the United States. At cork or balsa wood boiled in paraffin—is now dumped into the hopper till its weight forces it to mix with the inflowing water, and it is thereby taken into the pump and forced down through the piping. . Released at the lower end of the inner pipe it rises, but the water with which it is mixed, seeking the outlet pro- vided for it-in the other hatch, produces currents carrying the cork along, so that eventually it reaches all parts of the ship, rising the while against the cecks. When a sufficient amount of this buoyant ma- terial has taken the place of water, the ship rises. If the ship is too weak from prolonged corrosive action of the water, and the decks liable to lift, heated paraffin is run various religious proces- sions and especially at wedding proces- © sions as many as twenty or thirty of these lamps are carried on the heads of bearers who are engaged for the occasion and paid a fixed fee. : These lamps are high-pressure kerosene lamps constructed upon the principle of the kerosene torches used in the United States. The light is protected by a mica chimney and is very brilliant. Colored | globes are sometimes used. These lamps are no longer imported from the United States but are manufactured in Bombay. The “Bombay Lights’’ cost about five dollars or six dollars, while the imported kind can not be bought for less than sixty-five dollars apiece.

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The Martyr Pigeon of the British Navy. He Saved Four Men 4“ HERE in the world are we?” roars one of the observers in a huge biplane which is trying to make home after a run into a fog-bank, feared by all air- men. The raw biting air wraps around the four men in the machine, and nothing can be seen but blinding billows of fog. Darkness descends and they are still lost. There is a falter in the hitherto steady roar of the engine. ‘‘She’s starting to miss!’ yells one of the observers. The pilot silently adjusts his spark and throttle. She picks up, but the rhythm is again broken, worse than before. All faces are tense and nerves are tightening. Lost! Over the sea! Desperately the pilot struggles to keep the engine running, but with a final crackle she peters out and the machine starts to glide down. She lands with a splash in the water. She does not sink for she is fitted with hydroplane floats. The men cling to the machine. To repair her is hopeless in a running sea. ‘The pigeons! The pigeons!” a man yells. Here is a bare hope. After a struggle they manage to at- tach the message to a pigeon’s leg and release him. The little. messenger fights his way through the howling gale towards the place where instinct tells him his home lies. The val- iant little heart never falters. At last he feebly flutters into his - cote in England. It is his last effort though. His work is done, and his strength is spent. The attendant picks him up— dead. The rescue of the avia- tors after great suffer- ings is another story, just as true and exciting as this. Suffice it to say that they were rescued. The stuffed body of the martyr pigeon is preserved in a glass case in honor of his great deed; and in the hearts of those he saved he has another monument built of gratitude. Popular Science Monthly A winged messenger which saved the lives of four men at the cost of its own 4 4 Bomb-inspector Eagan examining a deadly contrivance recently found in New York You’ve Probably Escaped This Way of Being ‘Blown Up” BOMB containing enough dynamite to demolish the walls of the building in which he lived was recently found by ~ a resident of the Italian section of New York city. At first glance the object seemed harmless enough. It was apparently a can, about ten inches in length and three inches square, used to con- tain olive oil. But attached to the can was a fuse at sight of which the dis- coverer hurried to the policeman on post near by, and soon af- terward Owen Eagan, bomb ex- pert of New York, took charge of the death-dealing instrument. He found in- side the can about a pound anda half of dyna- mite, placed on a base of cement to make the bomb more effective. The fuse was about two and a half feet in length, and was connected with fulminate-of- mercury caps designed to explode the dy- namite. Fortunately the fuse was not burning when the bomb was discovered. © Underwood and Underwood

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a Popular Science Monthly The principle of the snowshoe applied in walking on mud when digging shellfish Shoes that Prevent the Wearer from Being ‘Stuck in the Mud” - LONG certain portions of the French coast there are extensive flats of mud that the tide leaves uncovered when it recedes. While these are by no means beautiful, they yet provide the habitants with profitable employment in addition to the usual fishing operations by reason of the various mollusks that live in the mud. To. obtain these the fishermen use long-handled rakes and forks, with which to dig the shell-fish out of the mud. How- ever, the mud itself forms a serious obstacle. It is so soft [Ww that a man sinks into it and | my cannot move about with ease. Hence, peculiar wooden shoes are worn which act in the same manner as a snow- - shoe. They support the weight by dis- tributing it over a greater area. Similar devices are in-use on the east coast of England, where they are called “‘pattens.” The picture shows how simple the shoes are in construction. An exhibit of wastefulness which is doubly reprehensible now when economy is a duty The: Process of Making Parchment Paper Y immersing paper for a short time in a fairly concentrated solution of sulphuric acid, the cellulose is converted into a gelatinous mags which fills up the pores of the paper, and, on being thoroughly washed, the paper is found to be parchmentized, or converted into a non-porous ma- terial resembling parchment (pre. pared skin of the sheep or she-goat), According to Alexander Findlay’s “‘Chemistry in the Service of Man” (Longmans, Green & Co.) such parch- ment paper can also be prepared by immersing paper in a solution of zine chloride; and by compressing together a number of sheets of such parchment paper, the compressed fiber, or “hard fiber,’’ so largely used in the manufacture of trunks and as an insulating material, -is obtained. Raising a Ghost to Prevent Waste |’ of Commodities OW would you like to have the ghosts of your misdeeds and the carcasses of your victims resuscitated for - your benefit? This is what a great Pittsburg electrical company did a short time ago as a gentle reminder to its employees that we are at war. A storage-battery truck was used for an exhibit. On it was accusingly arranged the material rescued from waste-boxes during one -- This included scraps of food ga from employees’ lunches, and material belonging to the company. The truck was run around the shop, a ei notice calling attention to 9; what it represented. | The company’s officials estimated that from thir- ty-five to fifty dollars’ worth of food was wasted daily, and hundreds of dollars’ worth of manu- - Thiswould bea total loss to the company if it were not for the efforts of a staff of “recovery men.” - facturing material. : hat tio! str old la

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Old Gas-Lamps UT on Blair Avenue, in a residential section of Cincinnati, a flower-lover had a happy inspira- tion. ‘There had been a change made in the street lamps used. The older -style gas-lamps were discarded, the glass globes were re- moved, and only the old poles and the lamp- frames were left. ‘‘Good enough!”’’ thought the flower- lover. Down in his cellar there was some old window -screening. It was the work of a mo- ment to rip the screen itself from the frame, take the family ladder to the sidewalk, and wrap and bend the screen to the prongs of the lamp-frame. Soil from the yard; seeds from the war-gar- den; water when needed —and lo, in a very short time each lamp-post had its hanging garden. A Breath-Guard—But Not the Kind You Mean MAN’S breath is often a betrayer of secrets. He may have been out . late, sitting up with a sick friend, but Popular Science Monthly 807 Hanging Flower-Gardens in when he reaches home his loving wife at once opens up her battery of reproaches. Now comes the news that two inven- tors in Osceola, Arkansas, have jointly in- vented a breath-guard of a new pattern. It is said to be efficient, An.old gas-lamp filled with flower- ing plants in a Cincinnati street Gripping attachment No matter how strong your breath the barber is safe. The shield shown protects him but not in the manner you were thinking of. It is intended to pro- tect dentists, barbers, and physicians, from inhaling the germ-laden breath of their patients or patrons. It con- sists of a small, curved shield of glass placed so as to cover the nostrils and held in position by a spring clip gripping the parti- tion wall of the nose on the inside. Many diseases are directly communicated through the inhalation of taint- ed air, and a device of this kind should be a boon to professional people who are com- pelled, by the nature of their duties, to be in close proximity to those whom they serve. The patronsof some bar- bers may also need it. Old Age Is Not a Matter of Years, But of Recuperative Power T would seem that the phenomenon of growing old has really nothing to do with the number of years that an individ- ual has lived, but depends prin- cipally on the extent to which he has conserved his recupera- tive powers. The human body wears out in two ways, i.e., either by long-continued use or by long-continued disuse. Inthe former case it is like bending a wire back and forth in one place until it breaks, and in the second it is the atrophy of or- gans or functions through dis- use. The only way to stave off old age is to eliminate all forms of abuse and live as Na- ture intended us to live.

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Cannon May Kill a Ranges of Five and Ten Miles; Machine | Guns May Fire Six Hundred Shots in One to-l Liv —al be . Disarm! Jiu-jitsu wrest- ling methods are introduced in warding off a bayonet attack. Whiletheseboys are here fight- ing as friends, there is a back- ground picture in their minds which adds zest and “‘pep”’ to their struggle Wringing His Neck Trying to disarm and disable his opponent by throwing him with a neck hold. What these lads must face “over there’’ lends realism to their work The One-Step A good grip on a man’s toe is by no means a hold to be “sneezed” at. These two troopers are doing strenuous work—offensive as well as defensive A Class in Hand-Grenade Throwing No, they are not training to become baseball pitchers! They are trying to toss cement balls into an enemy” trench indicated by.chalk lines. When they get across the ocean they will use deadlier missiles calculated to put a permanent quietus on some of their adversaries. This squad is the “kindergarten” class in bomb-throwing 808

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inute; But the Hand- P Hand Strugéle Still Lives in Modern War —and Our Boys Must be Masters of the Art © Photos by Edwin Ralph Estep A Strenuous Game A strangle hold calculated to break an adversary’s neck and prevent him from driving home that deadly bayonet. There is earnestness in the face of the unarmed fighter. You can see that his whole soul is in his work, for success or failure may mean all the difference between life and death to him some day—and to the Boche who opposes him A Dash to the Dressing Station Picking up a man lying prone on the ground and running with him on your back for fifty yards is not as easy as it looks to these huskies. It is all in the day’s work for the training ‘“‘Sammies.”” One man picks up the ‘‘wounded comrade” and runs with him for that distance, when he deposits him on the ground. Another make_ the return trip All’s Fair in « « * « and War The deadly grip this man has upon his adversary may well prove the undoing of a Boche who is unversed in the gentle art of self-defense as taught by the modern school of Japan and adopted by our ‘*'Sammies

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Woodenware and Hardware Hats the Stunning bonnet of military ef- fect. The foundation is a wire cheese-hood and it is trimmed with wire-screen and sink-brush Since we men editors are not masters of millinery lingo, the best that we can do is to describe this thing at the left as an ultra-chic and daring creation with a wooden bowl foundation trimmed with two butter paddles rampant and two dozen mustard spoons couchant Chaste sport hat woven of electric light wires, trim- med with a bright band of lamp sockets and a cascade of tassels Photos © Underwood and Underwood et hben = os ee ee A perfect dream (some might be inclined to call it a “‘scream’’) is this ultra smart chapeau, also built upon military lines. The cunningly shaped wash-basin body is tastefully trimmed on the side with two egg beaters crossed in the form of a big bow 810

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Very Latest Thing in Fashion Severely plain are the lines of this coquettish sailor hat made on a foundation of gas-hose and ; daintily trimmed with a wire } aigrette and imitation insects Right cunning is this natty tailor-made hat with rub- ber-mat brim. and ice-bag crown, trimmed with a band of gas-pipe and a stunning loop of the same material How could a feminine heart resist this ultra charming creation of artistic design? The straight brim is made from a pot-cover, the crown of coiled rope, and the founda- tion is a cake-pan strikingly trimmed with sandpaper triangles and a rope rosette 811

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“Cootie” Annihilators for General Pershing’s Army A train of modern sterilizing and fumigating wagons on its way to Uncle Sam’s boys on the battle front in France. This up-to-date apparatus was designed by Dr. Leon L. Watters, of New York, and Colonel F. H. Hartsock of the United States Medical Corps This apparatus will wage a war of extermination on the soldier’s enemy, the “‘cootie.”’ It consists of a high-pressure steam bciler in which the clothing of forty men can be disinfected in as many minutes. The “‘cooties,’’ or trench lice, are typhus-carriers, and must be destroyed. Even aside from this they are uncongenial companions

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Helping the Soldier Boys to Keep Themselves Clean by Means of a 22 Horse- Power Portable Laundry A stack of army coats that have been laun- dered, pressed and made ready for distribution A busy day at the re- ceiving and - delivering counter of the laundry which can do the washing for 4,000 men a week. A familiar camp sight. The customary Monday morning line-up at the laundry Photos © Iat. Film Serv. General view of the laundry. It consists of four wagons placed together and is operated by a 22-horse-power tractor. The Chinaman-power of the laundry has not been figured out 813

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An appropriate setting for the portrait of the soldier Breathes there an en- listed man who would not wear such a ring as this? This bracelet with the Pres- ident’s por- trait for young ladies A watch fob which shows the Ameri- can flag in full colors on a golden shield An incandescent Patriotic emblem of classical design to be worn in the but- tonhole of the lapel Service emblem lamp in the Na- tional colors is the latest novelty in patriotic decora- transparency for the front window which shows up well tions for the home aa r~ A neat little device that will hold three flags in place. Use three American flags in it or make a combination of the Nation’s flag and those of any two of her allies 814

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Three Cheers for the Red, White, and Blue This . writing case , makes it possible to write in any position, even squatting as this sailor lad is doing Aaseruss Emow Pat errs aero hd f Membership em- The new Lib- = blem of the Fulton erty clip for . go County Corn Grow- holding the ers’ Association pen or pencil What the soldier’s . writing case con- i ins is here shown. An up-to-date din- tains is ner ior is in the Itis compact, handy form of a soldier’s . and will please him hat. Doyou like it? ‘ This patriotic badge may appeal to young boys. ‘“Hel- met the Kaiser’”’ is the inscription it bears. We are not able to translate it eeecerrceve > Vrererceecereor ee ee ee ed Typewriter table dressed in the National colors, so that it will not interfere with the typist’s speed . 815 Even the baby’s dispatch car displays the red, whité and blue

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America’s Five Million Pleasure Cars Represent If it were possible to concentrate into one car the aggregate of 120,000,000 horse-power of the 5,000,000 pleas. ure automobiles in the United States that car would be able to travel with a speed of 155,000,000 miles an hour, somewhat less than one fourth the velocity of light. Ignoring speed laws it would travel from the earth to the sun in 35 minutes 4 Each vehicle uses on the average 500 gallons of gasoline a year, a total of 2,500,000,000 gallons. To pump all this gasoline would take one of the modern fireboats eight months. In that time, if the city had been in flames, that same fireboat could have thrown enough water upon the buildings of Manhattan Island to drench every structure 816

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a Total of 120,000,000 Horse-Power The Sua These fire boats are very powerful. At a pressure of 125 pounds their pumps can deliver 5,000 gallons of water a minute. Under favorable conditions the streams of water can be thrown to a height of one hundred and fifty feet or more

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From Logs to Legs:—Converting the At the right is shown a pile of Eng- lish willow wood, the principal raw material of the arti- ficial-limb industry founded in Wash- ington D.C., by a Civil War veteran who had lost a leg Photos © {nt. Film Serv. # The illustration above shows the first step—the sawing of the logs into pieces of various shapes before they are put away toseason. Only wood thoroughly seasoned is used for limbs 818

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Grow on Trees Into Limbs for Crippled Soldiers View of one of the work- rooms, where expert workmen turn out thou- sands of artificial limbs for the crippled soldiers Section of the stock-room of the factory. It con- tains enough blocks and partly shaped parts for ten thousand artificial limbs Many of the employees of the factory are cripples. Here are five who, to- gether, have only three natural legs, and who are now engaged in helping their brothers in misfor- tune. The factory em- ploys about 250 workmen

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Making Game Birds Pay The propagation of wild game requires care. ful attention to details. No one who does not feel a deep interest in the birds themselves is qualified to undertake it. Breeders of wild birds are advised to begin on a smal] scale and learn, by first-hand experience what those well versed in game farming term the technique. One expert in rearing wild birds advocates for beginners. the establish. ment of a game-raising section as an adjunct to other diversified farming and a gradual development of the project. A few ring. necked pheasants make an excellent nucleys for a game farm for the egthusiastic beginner, At Amston, Connecticut, on the property of Mr. Charles M. Ams, the National Association of Audubon Societies has built a wild-duck house to solve the problem of wintering. The structure is boarded down into the water to within less than a foot of the bottom of the pond. The pond contains a floating platform on which the ducks may feed, rest and find shelter Wild ducks and geese on the game farm of John Haywood, Gardner, Massachusetts. The common native Canada goose breeds readily in captivity. The main requisite for raising wild ducks and geese is a small pond es The pictures on these two pages come to us from Mr. Herbert K. Job of the National Associa- tion of Audubon Societies. They represent one phase of the interest in rearing wild birds. The possibilities are unlimited. Our domestic poul- try was originally a_ wild species—extremely wild—with

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On Your Own Home Farm They are easy to obtain and, furthermore, pheasant-raising is considered the most profitable branch of game-raising at present. The birds are light eaters, of good size, and they, as well as their eggs, bring excellent prices. Aside from the pecuniary aspects, however, there is a fascination in the raising of game birds which will amply repay the bird-lover for the time and money he may devote to this enterprise. If you are interested in raising game for profit or pleasure, write to the National Audubon Association, 1794 Broadway, New York city, for information on the subject which they are glad to furnish While pheasant raising is the most lucrative branch of game- breeding, many prefer to rear quails, as the young birds stay with the hen and run with her for shelter to the coop during showers, whereas young pheasants often merely squat on the ground iy ny] ¢ iY This is an exterior view of the duck-house at Amston, Connect- icut. It solves the problem of caring for the deep-water ducks whose feet, if kept out of water during winter, are apt to freeze a a 3 ee ME: tintin ie BZ Scan oe eg 5 aes ye restricted range. Thanks to game farming it is now the most abundant and _ useful species on earth. What may not be expected of the wild goose, the wild duck, the quail, the pheasant and the wild turkey when they too have been domesticated? Here isa fertile field for lovers of wild life

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a German Supply Station Is Totally Destroy ~ Oe « © Int. Film Serv. The Railroad Station Is Now a Series of Shell Craters . Supply railway trains running on newly-laid 5. Steel roofing for dugouts and gun positions. tracks. 6. Site of railroad station before it was destroyed . Piles of supplies, chiefly timbers for use in by French artillery. Note the big shell building dugouts. craters (about 60 feet across) caused by 420- . Rolls of barbed wire. mm. shells. . Piles of iron stakes used for stringing barbed wire. 7-8-9. Remains of railway tracks near station site. 822

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When a French Airplane Observer Gives the Range Rails Are Dislodged, Ties Broken, Ammunition Exploded, Supplies Destroyed . Broken and dislodged ties of former railway 13. Dugout of headquarters. The roof can be seen. tracks. 14. Ammunition park. Note the German soldiers supplies piled up. Perishable goods standing around. covered with tent cloth. 15. German soldiers standing in the road watching . Battery of four guns, with abris (shelter) for the the French airplane that snapped their pic- gunners. Emergency trench shows in front. ture and took observaticns of the destruction. 823

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= ——— =a ee Popular Science Monthly Saws Without Teeth to Cut Through Metal OT so very long ago the dis. covery was made in Ger. many that metalscould be sawed easier and quicker with rapidly revolving smooth disks of steel than with toothed circular saws, It was found that the cutting was done by the heat generated by the friction of the edge of the disk against the metal. The metal is melted at the point of contact, while the steel of the disk, being cooled by the air, does not reach the melting point, The disks need no sharpening and do not wear out so quickly as the toothed saws heretofore used for cutting metal. The faster the disk revolves, the © Kadel and Herbert If the blindfolded French soldier succeeds in cutting erated, and the quicker the job. the string, he gets the package of tobacco suspended Cut the String, Blindfolded, and Win a Package of Tobacco HERE are times when the soldiers in their camps or cantonments may give themselves up to rest or pleasure. After all, men. are but boys grown up and must have their recreation. Realizing this, the military authorities in France provide as much entertainment as possiblefor the men off duty, but as a rule the men must rely for their amusement upon their own resources. Games of every kind are played. The illustration shows one of the favorite forms of a blindfolding game played by soldiers in their leisure hours. Strings are stretched from tree to tree and from these strings pack- ages of tobacco are sus- pended. The player is blindfolded and pro- vided with a pair of scissors. With one hand he seeks to cut the string from which a package of tobacco is suspended. If he greater the amount of heat gen- Introducing the Busy Honey Bee— Ecclesiastical Architect OR centuries bees have excited won- der and admiration. Their archi- tectural skill is dwelt on over and over again. But did anyone ever hear of ‘ their building a church? It’s been i done. The accomplished and cultured swarm of superbees that did this belong to Mr. George F. Bower- sox, of Portland, Indiana. Unfortunately we cannot give the bees credit for originating the idea. Mr. Bowersox did that. He made a framework of light laths and covered it in so that the bees would consent to use it as a hive. They industriously filled in all the spare space with comb, which is precisely. what their owner wanted.’ The result is that they have allowed themselves to be beguiled into con structing a church, which, as can be seen from our illus- Bees built this littlechurch tration, is a really attract- succeed the tobacco is his. after their owner’s plan ive piece of architecture. sail e-

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Air Raiders Don’t Like These Lights URING their recent roids on . Paris the German aviators were greatly disconcerted by rockets which the French sent up and which discharged, before dropping, parachutes with bright- ly burning fuses. These para- chutes dropped slowly and their fuses cast a brilliant glare upon the hostile airplanes, making them a good target for the anti-aircraft guns. It is a safe guess that the Popular Science Monthly free fireworks were not enjoyed by the Germans. Artificial Birds Give a Realistic Appearance to the Flower Bed IRDS are sociable creatures. If one finds'a pleasant spot and seems to stay around it, his presence will do more than anything else to attract others. For this reason the use of artificial birds in garden plots and as props on which to train growing vines has found favor. The birds are pivoted on stakes of varying heights so that they may be used in beds of dwarf plants or tall ones. The effect is very pleasing to the eye. Artificial birds mounted on sticks are ornamental in the garden and attract other birds to the spot The ground pine seems to grow naturally right out of the boulder and the effect is very attractive How a Floral Urn Was Made From a Boulder LARGE granite boulder hollowed out as a receptable for a potted plant is the ornament which adorns the porch at the home of Paul Brochier; on West Adams Street, Los Angeles: The rock is practically round, except that it is slightly flattened on the base to give it a firm setting. With an ordinary rock-drill the inside of the stone was hollowed out so that a large flower pot would fit in exactly. A small drainage hole was drilled through to the bottom and a ground pine was planted in the flower pot. Old Tin Cans Figure in Milady’s Costume EW women who are proud of the fact that they wear hosiery, un- derwear and dresses made of silk, realize that old tin cans contribute from twenty to three hundred per cent. in weight to the glossy silks worn by them. The price of silk: has increased enormously and to enable them to sell heavy silks at a price that will yield a reasonable profit and yet be within the means of the average purchasers, the manufac- turers resort to the practice of weighting the silk with tin tetra- chloride, derived from old tin cans. Five thousand tons of tin were used for. that purpose in 1917. Don’t throw away the empty tomato cans!

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Ay My e%, A duffle bag with side opening and a waterproof ' clothing roll made of duck "Oi, TNT ma dal] adda Candle lan- terns made of cans, one for a tree limb and the other for a tent Some Home Camp Comforts For Thog | This collapsible canvas house tent 1s roomy and com- fortable, and can fy rolled into a bundle for shipment Boiler improvised of a small and a large pail, the small pail resting on stones Folding camp chairs, a slat curtain-roll table top and a gas lantern for the camp. A compact and convenient set of furniture 826 This three - piett camp shovel fitsm — a one-foot tool bor ©

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le > ee TP Who Love Life in the Great Outdoors SK 3 This life belt of rus - ber, inflated with air, is kept under pressure in a capsule attached to the waist at all times aii ianaeee Cobble-stone fireplace for burning the camp- ers’ cor’ ave and refuse Hand pump: Grid for pot A compact automobile folding camp-stove which uses either gasoline or kerosene for fuel \ Sairup to burner’ A folding oil-stove A home-made with two burners. It carrier for the occupies little space canteen made of a and is very handy strap and a snap lee | This waterproof duck kapok sleeping-pocket has an A canteen which is hung to an outside covering to keep the pocket dry when it overhead branch and tilted by rains. It is a very useful piece of camp furniture pulley and cord for filling a cup 827

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ac ITE OT LE LIE LEE The Story of a Wireless Hero How a wireless operator, with great ingenuity and re- sourcefulness, repaired his apparatus during a terrific gale By J. Andrew White LIKE to think of Wireless Operator I A. S. McKenzie as a hero, although he cannot be placed among those who have clung to a swaying table and sent out frantic appeals for aid as a submarine’s shells screamed by the radio cabin. Mc- Kenzie’s battle was against the greater forces of Nature. And not alone that he won, but because he stood a test of over- coming apparently hopeless difficulties by ingenuity and resourcefulness, his ex- perience is worth the telling. It properly begins at a point 700 miles from shore in a wintry sea. His ship, the Pennsylvania, was not large, nor new. She shivered from stem to stern with each plunge into the seething green wastes as the gale increased in fury; with terrifying regularity her after-deck was buried un- der heavy seas that swirled about the wheel-house and strained to tear it loose. Back in the saloon, off duty, the operator wondered; there had been storms, but never anything like this. A giant wave bore down on the strain- ing vessel. With a crash and an ominous long-drawn rip, the cover of No. 1 hatch went over the side, the funnel wrenched loose from its stays and the wreckage from a smashed-in bridge, pilot house and wireless cabin swept back with a clutter of doors that had once protected forward staterooms. Below, a muffled rumble conveyed the information that the cargo of liquid asphaltum had broken loose, threatening annihilation of propelling engines upon which safety depended. The Storm’s Work of Havoc Begins Then, in the tumult, a pungent smell of acid arose and large streams of oil entered the saloon. All hands were puzzled; but the operator knew. The glass plate condenser of his set was mounted on the deck, and the planking was anything but secure. A crippled set to oppose the greed of the furies! A stanch spirit sank before realization of the truth. 828 Slipping and sliding on the oil-soakeg floor, buffeted about by the roll of the ship, he fought his way out of the saloon. On hands and knees he struggled to the wireless cabin. The place was knee-deep in water, the set a wreck. On the floor the transformer coil, two pairs of phones, accumulators, the condenser and all the cells were adrift in a slush of broken glass. A glance ag. sured him that the service switch was up, the starter “off.” Salt water, however, had usurped the function of human hands and had made a connection which kept the motor running slowly. It must be stopped. Scrambling about, gaining a precarious hold and losing it with each wild pitch of the ship threaten- ing to drop him amid the swirl of broken glass and smashing equipment, he worked to a favorable position. A few tugs and off came the wiring. The Gale Redoubled in Fury The vessel rolled her top deck under water and pitched like a frightened steed. He flied the place, in search of the captain. That officer was found wedged in be tween the stove-in bridge and the pilot- house; he had squeezed into this position to keep from being blown overboard. McKenzie reported conditions. “Leave everything and go _ below!” bellowed the captain. ‘‘We can do noth- ing now but try to save the ship.” And below he stayed through a night of terror. There was no sleep for anyone. With the first flush of dawn the wind died down. The day broke clear, but mountainous seas still tossed the vessel about like a cork. No immediate need for an SOS appeared, but there were im- portant orders to be received from the owners, the captain remarked as he dist consolately viewed the wreckage in the wireless room. Every effort must be made to patch things up enough to get 4 message through. spt’ simi ts tt iia senso tipiaiein

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“I Listened and Caught the U.S. S. Proteus” WRAL y Standing knee-deep in water—transformer coils, phones, accumulators, and cells adrift in a slush of broken glass—salt water having established a connection that kept the motor ing slowly, and which must be stopped, a nearly exhausted operator, after hours of back-breaking efforts and dogged persistence, won the day—he got his message across 829

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830 Popular Science Monthly At nine in the morning the operator began to work, assisted by the ship’s carpenter. Time passed, but practically no progress had been made on the slippery floor; then a thoughtful mate sent up a bucket filled with sand. An hour had elapsed before the transformer was back in its case and made fast. The auxiliary and accumulators were removed entirely and the condenser set upright. Spare plates which had been kept on the floor had somehow remained whole, but the acid had attacked the tinfoil and it was peeling off most of them. The container was cracked. Asbestos Paste to the Rescue An appeal to the engineers brought some asbestos paste to the cabin, and a so-called repair was effected. The result of four hours’ intensive work was a con- denser haphazard in appearance but boasting twenty-four plates. With an intermission here consisting of space for a long-drawn breath, Mc- Kenzie turned to the task of drying out the rest of the equipment. The rheostats had to be taken down, dried and oiled with insulative oil. The starter and the transformer required the same treatment. Two solid hours were spent on the motor; first the brushes came off and the inside was oiled as well as possible; there was no time to take out the armature. Resourcefulness Wins an Inning It was eight o’clock then. Eleven hours of exhausting work lay behind the oper- ator, but the race against time did not allow for a stop for dinner. He tried out the set. The first thing to go was the generator rheostat. Patiently he re- paired it. It blew again. With twenty feet of iron wire wound on a pencil he created a resistance. This, after a series of patient experiments, performed its function, although the motor ran un- steadily and sparked furiously. Another precious hour had been lost. Once again the set was started, the key depressed and a radio land station call flew off across the sea. ‘“‘A great moment,’”’ McKenzie describes it. ‘I waited. No answer. When I tried again the starter burned out in two places. “Once more the asbestos paste proved invaluable; but the release magnet now refused to hold. With wire I hooked jt up. The motor started then; but this time the field rheostat went on strike,” More Repairs Under Difficulties Painstaking repairs were made, only to learn that although the apparatus operated, the generator rings were arcing across the dividing rings while the brush holders were leaking into the frame. “These defects were remedied,” says the operator, telling of his experience, “and I tried again. It was now midnight, I called CQ for a long time but received no answer. ... I had forgotten that the phones had been in acid and water all the day before. “Although I dried out the headgear in’ the steam oven it was as wet as ever again in ten minutes. I tried cleaning the phones, while warm, with gasoline. Stil] I could hear nothing. “The aerial was intact. I tried the tuner with the battery and found it dead. At two in the morning I succeeded in dry- ing it out. At Last a Hopeful Sign “T listened and caught the U.S.S§, Proteus. My spirits rose. I called him —and away went the condenser, shot to pieces! “Two hours later it was rigged up again, but the motor brushes were short- ing through the frame. “T quit, and turned in for a nap.” At six in the morning, after a scant hour and a half’s sleep, McKenzie turned to the job again. The sea still lashed vi- ciously at the vessel’s side. Practically all his work had gone for nothing. Every seam in the wireless cabin was open, the roof badly sprung and his set as wet as ever. But at noon, after six hours of back-breaking effort, he considered everything in readiness and again tried to start up. Nothing happened. All the current went to ground through the soaked insulation. With dogged persistence he turned once more to the task. Hours slipped by, precious ones. It was eight o’clock in the evening when a nearly exhausted operator concluded his long labor with motor and wiring. But it was done; a loyal sense of duty was rewarded— this time he got his message across! to’ lu SO) fre his sh th

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Aquaplane Racing Full of Genuine Thrills Novel racecourse provides hilarious fun with many thrills but no danger Each channel is supported by tubular floats. The tracks, two or more in number, are elliptical. The shallow water eliminates danger but is wet enough for thrilling spills ID you ever see an aquaplane race? three, or more parallel channels which If you like fun, do not fail to visit form the tracks for the aquaplanes. the nearest aquaplane racetrack. The moving power is a cable kept in Of course, you have seen aquaplanes in motion by a gasoline or other kind of’ tow of fast launches, crazily engine. The aquaplanes are lunging in the turbulent Re lowing Post attached to upright posts of wake of the propeller, while rame a framework, the submerged some daring bather made part of which runs on small frantic efforts to maintain WV : trolley wheels, within a a grooved trolley track, grip- his balance. The aquaplane racetrack Ee e f ping the cable by means of shown in our illustration is We * Trolley Track a “‘gripper.”’ the invention of Hubert A. “% The race is full of thrills Myers, of Toledo, Ohio. It ghowing how the “gripper” 2nd spills, duckings and may be divided into two, engages the running cable jeers, laughter and cheers. 831 ees ee eG Bie EEE a ae we iy pe aaa a Party Sa eer wee

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Popular Science Monthly ee a bien: UM sce ec Bote ere espe > ‘2 Ep OW Ree. cme “ome No Very Great Danger ip Making Explosives N a paper read before a med. ical association in the East, Dr. W. G. Hudson, medical diree. tor of E. I. duPont de Nemours & Co., manufacturers of ex. plosives, recently made some interesting statements concern. ing the risks connected with the manufacture of powerfy] explosives. He asserted that the dangers of that industry were greatly exaggerated. As a matter of fact, railroading shows much higher injury and death rates than the manufac- ture of explosives. Of the ar. A Giant Strawberry Shortcake. It Had to be Cut with a Cross-Cut Saw VERY year the little town of Burton, situated on Vashon Island, a few miles from the city of Tacoma, holds a good old-fashioned strawberry festival to which the public is cordially invited. The Island Commercial Club, a “‘live-wire”’ in the community, conducts the festivi- ties. Heretofore plain strawberries, sugar and cream have been the order of the day, but the committee that had charge of the affair this year took it into their heads to do something different and original. Accordingly they waited upon two members of the Burton Woman’s Club, far famed for their culinary accom- plishments, and told them to put on their thinking caps. The ladies rose to the oc- casion and the result was the making of a strawberry shortcake of exquisite taste and gen- erous proportions. No knife equal to the situation could be found, but H. G. Parkes, presi- dent of the Commercial Club, suggested the use of a cross-cut saw. Every- body echoed “‘Why not?” The problem of ieliies a Sialibaee erates, too big for a knife, was solved by sawing it Remove the handle of your grip and it will be safe from thieves cidents which occur in explosive factories only a small percentage are actually caused by explo- sives. Four-fifths of the accidents are due to carelessness of negligence of em- ployees who disregard the precautions necessary wherever men. are working with tools and’ machinery. By increasing the share of work done by machinety and reducing the number of workers-in proportion to the increased use of mechan- ical appliances, the manufacturers of explosives are striving to diminish the hazards connected with their business. Use This Detachable Handle to Protect Your Grip ‘ N order to make it at least very awkward for a thief to steal a bag, Mr. A.C. Aagebery, of Indiana; has handle. This can~be fitted to both new and iece fits and from which it is removable by pressing a button. The handles being non- interchangeable, theft by fitting another handle is not possible. The thief would have to carry the bag under his arm. com invented a detachable old bags and _ valises. It is merely a--pair of sockets into which / the removable handle p the war due of 1 road ings. com tha of | imp to v pro mec ing coa on | devi mea \1

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gestion of rail- road traffic since the outbreak of the war has been partly due tothe detention of loaded cars in rail- road yards or on sid- ings. In many cases companies pleaded that the scarcity of laborers made it impossible for them to unload their cars promptly. Hence, mechanical unload- ing of freight and coal cars has _ be- Gest of the con- come of vital importance. Recently a Chicago inventor put Unloading Freight Cars by Machinery — No worry then about shortage of labor duce the cost of un- loading to one-third: of what must now be paid to shovelers. The device consists of an endless-chain bucket elevator carried “by projecting arms which are counter- balanced by a con- crete block at the opposite end and mounted on a piv- oted frame supported on a traveling bridge or crane which strad- dles the car and can be moved from car to car as the work proceeds. One man is sufficient to operate this Accelerating the unloading of railway cars by the use of endless-chain buckets on the market a mechanical unloading machine, which, according to the mate- device, which, he claims, will not only rial, will unload from thirty to forty mean a large saving of labor but also re- tons an hour. At that rate one operator with this machine can unload five cars in one day. To do the same amount of work by the old or twelve men. The bucket-chain elevates the material to a horizontal belt which deposits the material re- moved from the car wherever it is wanted. Both conveyors are operated by small electric motors controlled from the operator’s cab. The entrance of the United States into the war has acted as a stimulus to inventive genius, and since the war necessarily removes from ordinary channels of labor a large percentage of men, any device that holds out promise of usefulness in sub- stituting mechanical labor for that of man is worthy of more than passing consideration. If this inventor’s claims are sub- stantiated, one of the most serious causes of delay in The traveling belt (at left) receives its burden from \buckets unceasingly and deposits it where wanted nated. freight-handling will be. elimi- 833 method would require about ten —

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Popular Science Monthly Seco Se The combination croquet-pool game. Except for the pockets on the corners and sides no special apparatus is used when the game is played outdoors. For indoor play lighter balls are desirable Combining Two Favorite Sports— Croquet and Pool ROQUET enthusiasts and devotees of the pool table may enjoy the new game, shown in the accompanying illus- tration. It may be played either out- doors or indoors. Pockets are fastened in place on the ground exactly as on a pool table, one at each corner and on each of the longer sides. By numbering the balls combina- tions such as lend fascination and excite- ment to pool may be obtained. Except for the pockets no special apparatus is necessary. The regulation croquet balls and mallets answer the purpose; but for indoor use lighter balls may be found more desirable and less noisy. Water-filled Roller Combines Scraper and Handle-Lock MANUFACTURER of Berea, Ohio, has recently placed on the market a com- bination handle-lock and rol- ler-scraper for use with lawn rollers weighted with water. This device holds the handle upright when it is not used, thus -making it unnecessary to counterweight the handle. The scraper may be lowered for cleaning the roller surface. The weight may be regulated by the volume of water. When roller is not in use the holds up handle Over Fifty Different Woods Are Sold as Mahogany . %” HE name “mahogany” is applied commercially to more than fifty dif- ferent woods. Perhaps half the lumber now sold under that name is not true mahogany, for the demand greatly ex- ceeds the supply. The tree is only native to the limited area between southern Florida and north- ern South America. Nowhere else does it really flourish. But the public will have mahogany. Women want it for furniture, business men prefer it for office fixtures, and teak and mahogany are rivals in the affections of ship-builders. Therefore substitutes flourish. It is not surprising that the real wood is so expensive when it one hundred to one hundred and fifty years for a mahogany tree to reach merchantable size. Most of the substitubie bear little more than a general resemblance to the genuile wood, but skillful finishing makes them very much alike Experts can usually distie guish between them by the aid of an ordinary pocket lens. The efforts of the super ficial, however, to judge the wood by its appearance, lock weight, grain, and color-often lead them astray. is learned that it takes from

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How a young woman taught herself ning and engaged in a business that __. YOUNG woman in Los Angeles, Mrs. Carl Sherman, has taught herself fur-raising and tanning and maintains a “rabbitry’ of three or four hundred choice specimens. She is the founder and instructor of the “Southern California Coney Fur Club,” and has a large established trade both in skins and garments of fur. Instructions in rabbit- raising and tanning were obtained from the Government. To learn garment-making she sent to Chicago for the cheapest set of furs of fashionable cut that could be had. These ot (ae ee ee ee forty or more dollars. Soa ee ae a! OS Only aristocrats of the rabbit world occupy apart- ments in Mrs. Carl Sherman’s strictly modern hutch 835 Making Money Out of Rabbits After being tanned -the skins are softened by scraping and rubbing fur-raising and tan- anyone can learn Himalayas, English Snow Shoes, Imperial Blues, Flemish Blacks, French Silver, little Jap- anese and other varieties. And in her cottage are chests full of preserved skins that sell for eight dollars each unmade, while her transactions in made skins amount to several hundred dollars a month. Yet a child could learn the trade, she declares. The formula is simply five gallons of water, four pounds of common salt, and two ounces of sulphuric acid, made into a solu- tion, in which the skins are soaked from six to she carefully ripped up, studying the twenty days according to their weight; seaming and finish, and afterwards using they are then dried in the shade, pulled the pieces for patterns. Now she makes and stretched by hand, and rubbed over fur sets—muff and cape—that sell for the edge of a hardwood board until pli- able. Finally they are immersed in gaso- In her own back-yard, on a fifty-foot line, rubbed over while wet with corn- lot, are pens of up-to-date construction — starch or fuller’s earth, dried in the sun, full of aristocrats in the coney-world— and brushed. Having mastered the business in its details, Mrs. Sherman last October formed a club of her neighbors, which in December had thirty-two members, all rais- ing their own rabbits, tanning their own skins and making fash- ionable fur pieces for the trade. The club prepares an exhibit of fur garments for the annual show of the California Rabbit As- sociation. This exhibit includes a wide variety of fur pieces, such as hats, muffs, capes, scarfs, slip- pers and bags—all of fashionable cut and beautiful shades and markings. The club never lacks a market for its wares; as a mat- ter of fact, the members find the demand exceeding the supply. ‘ orese

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Six motor-cycles on each side in this tug-of-war pulled until they were exhausted Two Teams of Six Motor-Cycles Have a Tug-of-War “A RE you ready? Go!” Then follows a series of explo- sions. “Gr-r-r! Bang! Bang! Bang! Whoosh! Pop! Pop! Pop!’ This, coupled with clouds of sand flying, and shouts and laughs from the spectators, gives a slight idea of what ‘recently took place on a California. beach. Following a friendly ar- gument concerning the pulling power of different makes of machines by members of the Los An- geles Motor Cycle Club, a tug-of-war for motor- cycles was arranged. The competing machines were arranged in teams of six, and hitched to a one- ~ hundred - and - fifty - foot manila cable. The en- gines were started up, and, at a given signal, all the clutches were let in to- gether. For ten minutes ° the game little machines pulled each other back and forth along the beach. At the end of that time they had all dug themselves in until they could run no longer. The winning team won by just eight inches! ~ Popular Science Monthly Bathing both eyes at the same time Bathtubs for the Eyes. They Have Running Water, Too RIEDRICH MAIER, of Elizabeth, N. J., suffering from some eye trouble, consulted an eye specialist who recommended, as part of the treatment frequent bathing of the eyes in eold : water. Mr. Maier found thege baths beneficial, but: dig not like the manner of taking them. After having given the matter consider- able thought, he made a pair of miniature bathtubs . for the eyes, fitted them to the head like goggles, and fastened them securely in place by a strap around the head. He fitted each of the little bathtubs with an inlet at the top and an outlet at the bottom. Connecting - the inlets by means of rubber tubes with a water reservoir or the faucet and turp- ing on the water a stream of water flowed through the two bathtubs, washing the eyes and eventually draining through rubber tubes connected with the outlets, into a basin or the sink. The inventor was thoroughly satisfied with the efficiency of this apparatus and so was the eye doctor for whom he made a copy of the device and who used it with ex- cellent success in his clinic, The device is of great value in all cases where a continued washing of one eye or both eyes is neces- sary. As the cups are provided with glass fronts, like goggles, the doctor can observe the effect of the washing upon the eye of the patient. The device can be used for but one eye or both, as de sired, and the patient may be standing, sitting, or lying down. a Theillustration explains, better than words can do, the method of using this apparatus. ref sole mil gre lect mo eac col wo cor tio! the inc the thr vat the anc

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Making Soap from Table Refuse O conserve the fats contained in the table refuse and dishwater of the soldiers’ mess, the British military authorities installed grease traps. The fat col- lected in these traps averages more than one ounce for each man daily. The trap , consists of a tin-lined wooden box, divided into two compartments by a parti- tion which does not reach the bottom by about four inches. The dishwater and the table refuse are poured through a strainer into the vat. As the water cools, the fat forms a crust on top and is skimmed off. This Press Can Make Two Thousand Bricks of Fuel a Day HE scarcity of coal in all belligerent countries has imposed upon all na- tions the necessity of exercising great economy in the use of fuels. Long before the war economic reasons made it de- sirable to find some method of utilizing coal dust, sawdust, peat and lignites for Briquettes were in- heating purposes. Popular Science Monthly Columbia University’s fifteen-ton sundial. You can’t set this timepiece ahead an hour to save daylight Giant Granite Ball Tells Time with Great Accuracy HUGE shining ball of green granite, weighing more than fifteen tons, is placed at the edge of the campus of Columbia University, New York city, for use as a sundial. stone base on the upper surface of which are mounted two curved brass plates. The edges of the oval shadow cast by the It is set on a solid vented and to some extent used. The ball fall along the two brass plates and a war revived the interest in briquettes, and several new presses for making them were invented. The device shown in the pic- ture is by.a French maker who claims that one of these machines, operated by three men, can turn out from fif- teen hundred to two thousand briquettes daily, each weigh- ing about six and a half pounds. Bri- quettes may be made of coal dust, sawdust, shells of huts or cacao beans, leaves, peat, etc. comparison will give the correct time. Professor Jacoby, of the astronomy de- partment, has estimated that the degree A fuel-briquette machine which can turn out about two thousand briquettes a day of inaccuracy of the sundial is never more than a frac- tion of a minute. The monumental ball was a gift of the class of 1885 to commemorate the twenty-fifth an- niversary of their graduation. Pro- fessor Jacoby, real- izing the possibili- ties of rendering the ball useful as well as ornamental, had the two calibrated plates attached.

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Popular Science Monthly “fairy grass.”” On and ‘on she wanders, stopping here and there to gather soma purple, lavender or almost black grass, some fragrant Sea-Lavender, some early golden rod. Along the rail. road tracks she gathers clumps of Poligonella, oy cousin to Scotch heather, and, every now and then she makes use of the net which she carries to capture some tiny butterfly with When this canvas-covered frame is hauled across the field, it bewilders the grasshoppers so they hop into it Catching Grasshoppers by the Bushel N a Western State where grasshoppers threatened entirely to destroy farm crops, an inventive farmer made the grass- hopper-catcher shown in accompanying illustration. The device consists of a framework over which is stretched can- vas. On lower front section the teeth of a mowing machine are mounted to form a “catcher.”’ As the contrivance moves - over the field the insects jump and are caught by the catcher. A horse pulls the grasshopper catcher along. How a Woman Makes Money by Putting Nature Under Glass YOUNG woman, dressed for “hik- ing’ and walking with a brisk and elastic step, is approaching from the direction of the town. Her eyes, clear and keen, searchingly wander from one side of the road to the other. At a sandy strip she leaves the roa and begins to gather some of the graceful, feathery whisps of black grass growing there. She chooses critically and uses great care in placing the grass in the tin case which she carries by a strap over her shoulder. ‘-A short distance beyond that sand lot, a marshy meadow attracts her at- tention. Boldly she wades into the swemp and seems pleased when she finds some of that dainty and delicate grass which is known as gorgeously-colored wings, Who is this woman? Why does she eollect these speci- mens, many of which seem so unattract- ive and commonplace? If you have taken your stroll in the vicinity of Lexing- ton, Mass., you will recognize her as Miss Rose Whitney Smith, who has turned the pleasures of a naturalist’s work to prae- tical use and has built up a flourishing industry in‘ which grasses, flowers, but- terflies, etc., are skilfully employed for decorating trays, mirrors, screens, ete, The specimens are carefully prepared and arranged artistically upon a background of silk, protected on the one side by plate glass, on the other by a sub- stantial wooden or metal back. P Miss Smith in her - “Nature Shop,” . and, in the frame, a sample of her artis- tic decorative work fame = © go te * sy = Oh ct eet 8 CO) eS

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Ornamental Concrete Pools Take Place of Old Swimming Hole HE delights of outdoor swimming in summer are made possible in cities py the building of concrete swimming pools. The expense is so small that even residences can afford them. When set among forest trees, a concrete swimming pool is an attraction. Water may be se- Popular Science Monthly 839 Making Use of Tomato Seeds and Skins OMATOES are used in enormous quantities in the United States for food purposes and as a condiment, and the industry of canning tomatoes and that of making catsups or soups of them has developed to considerable impor- tance. In the making of soups and cured from natural springs or streams. The con- crete pools are easily waterproofed by proper construction. The main point to avoid leakage is to use good ma- terial so pro- portioned as to get a dense mix- ture; this, when well tamped, makes walls and floor wa- ter-tight or prac- tically so. Con- crete pools are procf against corrosion, and if well built are — practically perma- nent. Therefore the cost of excavating and construction may be considered prac- tically the only expense. Ornamentation consisting of balustrade and columns will, of course, increase the expense. It is in the inland city where the youngsters never get a chance to splash about except in the bathtub or some abandoned quarry that the concrete swim- ming pool is most appreciated. The best type of pool for such places is exemplified at Austin, Texas. This pool is 200 feet long and 100 feet wide. For the first twenty-five feet it has a depth of twelve to eighteen inches, and accommodates scores of small children. In the next 150 feet the depth ranges from three and one-half to four and one-half feet, while the depth of the last 25 feet, for diving, is eight feet. The pool is constantly filled with filtered water, supplied at the rate of five hundred gallons a minute. Concrete swimming pools bring delight to city-confined youngsters of all ages. The cost of construction is the only expense catsups only the pulp of the tomatoes is used and ueretofore the skins and seeds were discarded as useless. Recently economic chemistry has called attention to the possibility of utilizing both theskins and the seeds of the to- matoes. From the seeds 17.3 per cent of oil can be obtained, which has an agree- able smell and taste and a caloric value equal to that of olive oil. When treated with driers it acquires good drying properties, and is also useful in soap making. The seeds from which the oil has been removed and the skins of the tomatoes can be pressed into cakes which have considerable value for feeding cattle. Or the mixed mass may be spread for fertilizing purposes. Its manurial value was found to compare favorably with barnyard manure in potash, phosphoric acid and nitrogen. Considerable work has already been done in Italy and other foreign countries toward utilizing tomato refuse and in the Italian province of Parma about 12,000 tons of skins and seeds are worked up into oil and fertilizer every year. In the United States, however, this matter has not yet received proper attention. Stress of necessity, however, gradually calls at- tention to the value of many things for- merly regarded as useless. SS :

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A steam cooker set over the or- dinary tea- kettle for canning fruit i ee A A TE ee Housekeeping Made Easy ALL RL LIE ALE LA WEAN A double egg-beater of | new design driven by a \ Pomeranian An ash barrel truck that can be pushed up and down the steps A double boiler, with removable A convenient chair bottom, for for telephoning at cooking rice and the home or office other cereals 840 Comb cleaner made up of threads in the form of a razor stropper. It may be washed when necessary An attractive — holder for . the whisk _ broom. The broom forms a Fiji skirt for the girl An electrically operated ironing roll for the home laundry. Itis heated by gas A kettle cleaner which has brush and scraper on opposite sides

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Housekeeping Made Easy An electric washing ma- chine which works on the vacuum principle FT > Se F is : on & °o v 7 f Adjustable brackets to make curtain poles fit any window ,* ir , / & on _____- aaa t. ? se A convenient hanger for the tele- phone book which snaps into the hole -in the book WMA AWWH Vadamddddddduduadamumueda ccd Illuminated push but- - j tons on an electric jo Y= ilight ~switch—coated lj with luminous paint A cake tin with a detachable A smoking stand with trim for cakes of all sizes ash tray of original design Grill or broiler for céoking steaks over a single-flame gas burner A new design of a pot-cleaner which This little attachment is shaped like a_hat-stretcher tilts the chair as desired

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Garage Doors that Save Space and Time Some fold up like a screen; some swing around a corner; and some can be operated merely by pushing a button who builds his own garage is con- fronted .with the problem of select- ing a door which will require as little inside space as possible and yet give the least trouble in opening and closing. The old-fashioned swinging doors, like those in our dwellings, are not space- saving enough to suit modern conditions. Whether they open inwardly or outwardly, they require al- together too much space for their oper- ation. Numerous ways have been devised to overcome this difficulty. One of the simplest plans is to make the door of several narrow parts hinged together in such a manner that they fold up like a Fy wo buités i the automobile owner This electrical device will open or close the garage door. The clerk in the office can do it by pressing a button screen. A door of this type, for a two- car garage, is shown in one of the illustra- tions accompanying this article. In that case the door is divided into five hinged parts. The illustration clearly shows the manner of operating it. There are many kinds of sliding doors. One of the pic- tures illustrates onein two parts working like the sliding doors of show cases. Another kind shown is the sliding door which is swung around the cor- ner. Both these types re- ing and closing, are shown in the accompanying pictures. This shows one of the ordinary _ sliding doors with two parts | aS I ae The doors of this garage fold up like screens and are operated by an electrical control from the garage office 842 quire but little space for open- but they must be mounted on roller-bearing hangers if they are to be operated without too great exertion bya woman or child. Types of such hangers ateaitepire pn connect tie it

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adidas Reyes proven tO sees The doors of large public garages have to be opened very frequently and at all Popular Science Monthly 843 may be operated depends primarily upon the nicety with which all parts are “itted hours of the day or night. This neces- and upon the quality of the materials sitates constant attendance upon them. The device shown in one of the illus- trationsenables the clerk or stenogra- pher in the garage office to open or close the heavy gar- age doors without leaving her desk, simply by pressing a button. The de- vice. consists of a small electric mo- tor geared to a cable-drum. The current is controlled through a set of push buttons and a relay. This garage has folding doors that slide in grooves and require little “elbow room’: An Automobile that Got Its Power from the Street Mains When the starting button is pressed, the current is sent through the motor which operates the drum and, by winding up the cable, pulls open the door until a metal contact on the door itself comes into play against a switch-bar, supported by the small overhead frame that carries the motor. This shuts off the current and leaves the door open. To close it, a second button is pushed and the door is closed in the reversed order, with a simi- lar switch to shut off the current when the door is closed. It is self-evident that the ease with which large doors Different styles of roll- ers that are used for the sliding doors of garages > 2 This sliding garage door swings around the corner and requires very little inside space used. An ounce of prevention being worth a pound of cure, it would be poor economy to resort to inferior labor or material to save a few dollars on the initial expense, only to have to pay a repairman a more or less heavy bill after a short time. N automobile provided with a com- pressing plant by means of which gas could be taken from mains in the streets and compressed into the cylinders, in which it was stered as fuel for the machine, is the work of W. H. Dunkley of Bir- mingham, Ala. The plan included the employment of charging stations erected in the streets. Payment for the gas could have been made by means of slot me- ters and gas pass keys. The Dunkley automobile was made in the early days of the use of coal-gas as a-fuel for machines. It had a twin-cylinder opposed horizontal engine and the port-. able gas compressor was made up: of two water-cooled cylinders at right angles to and above the power cylinders. The cylinders in which the gas was stored were of the standard type used for oxygen. An idea for fitting hollow disk wheels as auxiliary reservoirs for gas was also evolved by Mr. Dunkley.

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Er Building a Subway Under a Subway Little do New Yorkers know that they are traveling on a suspended subway even though it is underground By Howard B. Gates, C. E. no doubt remember the time when the possibilities of subways asa means of rapid transit were as little realized as the practical application of the airplane, in its present development, is now considered, to our everyday life. But within the last fifteen years a most wonderful system of subways, comprising more than two hundred miles of under- ground railroad, has been built in New York under enormous difficulties at an expenditure of more than $400,000,000. Statistics show that nearly 2,000,000 persons are carried by this system every day and that more than seventy-five per cent. of this number seek its ac- commodation between the hours of six and nine o’tlock in the morning and be- tween four and seven o’clock in the evening. One of our largest railroad systems, with some 26,000 miles of track and traversing thirteen states, carries M ‘we residents of New York city such a structure beneath an existing and operating subway, without entering or disturbing the structure above. Al- though the average weight of the subway may not be more than a ton to the square foot, there are points, at the columns for instance, where concentrated loads of two hundred or three hundred tons, together with adjacent heavy and rapidly moving trains, make any dis- turbance to the equilibrium or stability of the temporary or permanent supports a matter of considerable responsibility and concern. Such a piece of work is now in progress beneath the present Times Square sta- | tion at 42nd Street and Broadway, passing diagonally beneath that station for about 250 feet of its length. Any in- terruption to operation at this point would congest the entire system, and yet, under a con- siderable portion of that structure, the but one-third of this original foundations number. During “rush” hours, even standing room is at a premi- have been supplanted by a complicated system of steel beams and timber um, although ten-car _ ¢ supports. Traffic is trains, each carrying 2,000 persons, are oper- ated under a one-and- one-half-minute head- way, controlled by elab- orate electrieal signal and emergency stop de- Sy vices, all of which must bo \ines of Present Subway i 8 ) maintained and the 300,000 persons who use the subway daily at that point do not even know what is going on beneath them. The new struc- ture also has four tracks, two local and two ex- press tracks, and will be operated by the Brook- lyn Rapid Transit Com-- pany. Connecting pas- sageways will lead from operate perfectly to 42° make this service pos- —— sible. ‘ The difficulty of con- 3 structing such an im- — w portant and complicated - w system through any of New York’s busy thor- oughfares, loses much in a comparison with the difficulties of building Diagram showing relative locations of the old and the new subways 844 the transit company’s present, recently com- pleted station on’ Broad- way between 40th and 42nd Streets tothe Inter- borough station above.

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Popular Science Monthly Times Square old subway /’ 7 New York’s Two-Storied Subway While train after train, loaded with passengers, ran into Times Square station of the New York sub- way and out again, and while millions of persons, on foot and in vehicles of every character passed over the spot on the surface, a new, four-track subway, to be operated by the Brooklyn Rapid Transit Co., was constructed, crossing 42nd Street under the tracks of the old subway. Can you realize the tre- mendous difficulty of the engineering task involved in the gigantic undertaking? Read how it was done.

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846 Eliminating all but the most vital technical details, the problem becomes one of blasting the rock from beneath the present station over small areas, which are self-supporting and which are subsequently shored by steel beams and timber supports before any further prog- To allow for the blasting and removal of the rock with- out endangering, to any serious extent, ress is attempted. these temporary supports, the ar- rangement of the shoring must be changed from time to time until enough of the new structure can be finished safely to sustain the struc- ture above. The support is arranged temporarily until the new work is completed, where- upon the permanent footings of masonry are placed. By referring to the illustrations, it will be seen that, while a meshwork of light steel beams resting on posts or other temporary work serves to sup- port the platform and lighter portions of the station, the shoring of the plat- form columns, each of which is com- puted to carry a load of about two hundred tons, has to be advanced in slow and expensive stages. The cast- iron bases of the columns are first carefully exposed and enough of the foundation concrete and rock removed to _ allow placing large steel beams beneath sides of base. Popular Science Monthly S BOUND LOCAL | SUBWAY 0 How It Was Done The top diagram shows the first step. Large steel beams were placed under the partly exposed col- umns of the old subway as a shoring and wedges hammered in until the weight was lifted. Then these were replaced with a single heavy timber post, directly under the original column. As the new steel-work progresses and is filled » with concrete all the shoring is taken away until at length the structure stands complete, one subway on another Wherever the headroom or working space is sufficient, these beams are sup- ported on well-placed timber columns beneath which steel wedges are driven until there is a visible separation be- tween the cast-iron base and its original foundation, indicating that the full load of the column above has been transferred to these temporary supports. The rock foundation is then removed to about a foot below the roof of the new subway, whereupon a single square timber post, accurately centered under the column and wedged to take the full load, re- places the shoring beams and releases them for use at other points. Working at the new subway roof level, small rectang- ular cuts or “drifts” are excavated and timber posts placed for the support of the structures above. Where the character of the rock permits, the excavation is next made to a depth sufficient to as- semble a portion of the new structure. Where the full depth cannot be “excavated without endangering the supports, long “run- ner” beams, upon which several sets of roof girders are placed, are set in concrete _ bearings upon the rock. An- other “pick-up” of the platform col- umn is now made by means of a crib- work of steel beams and blocking, built up from the perma- nent roof steel.

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The method of procedure in excavating, as described up to this point, has been in the direction of the width of the new structure, but with the “runner” beams in place, the work progresses in the di- rection of these beams. - As fast as the rock is removed beneath the “runners,”’ posts are placed to carry the free end and, with the other end supported on the original rock, the remaining foundation can be removed with little danger to the subway overhead. The new structure is next completed, whereupon all temporary shoring and supports are removed and the subway above is restored upon the roof of this new work, filling all voids between the two structures with masonry. It goes without saying that the work is carried on from the adjacent unfinished portion. This Tobacco Pipe Is Built Like a Cornet, But Isn’t Musical TOBACCO pipe of unusual design ‘has been invented by Warren Mur- ray Baechtel, of Hagerstown, Md. Every pipe-smoker knows that the longer the stem of his pipe the cooler will be the smoke. Pipes with stems a few feet long have been in use in different countries for many years, but their awkward length precluded their use outside of the house. The inventor of the pipe shown in the illustration circumvented the difficulty by coiling the stem of the pipe like the tube of a cornet or signal horn. The coils are connect- ed at their lower end to form a dripping -chamber for receiving the saliva which accumulates in the stem. Each coil has an independent open- ing into the dripping-cham- -ber and a screw cap at the bottom gives access to it for the removal of the ac- cumulated saliva. The smoke, in passing through the coils of the stem, is drained several times of saliva and nicotine. Popular Science Monthly The long, without being awkward, insures a nice cool smoke The base is rigidly anchored to the ground; yet it “gives” slightly when the runner hits it A Baseball Base Which Moves When It Is Hit N improved baseball base, which is anchored to the ground so that it is secure and yet is able to yield, has been invented by Sydnor M. Falconer, of Washington, D. C. Bases, as they are now fastened to the ground, are often torn from their moorings, or they are so immovable that they injure the player when he strikes them at great force. The base described is provided with a coiled spring, which enables it to move slightly _ from its anchored position and thus pre- vent the player from getting injured. When released, the base returns instantly to its former position. When a base-runner comes sliding, hands first or feet first, with considerable speed against an immov- able base, he is very apt to sustain a sprain or other serious injury. This device should therefore appeal to those players whose ambition frequently makes them risk their limbs in the base stealing of bases. A similar de- vice, which would make the football-player’s anat- omy bend instead of break on contact, is desirable. coiled stem,

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Popular Science Monthly The cane, with sewing-bag attached, is stuck into ground near chair, leaving you unencumbered Red Cross Knitters and Sewers, Please Learn How to Use a Cane F you enjoy sewing out-of-doors, but object to a lap-full of the necessary materials, here is a little device which will make sewing in the garden an unalloyed pleasure. And best of all, you may not have to buy a single article in order to have this attractive combination sewing- bag and table. Take a cane and attach to it a cretonne bag about twelve inches long, and divided into two parts. Stick the cane into the ground, and you can sew as com- fortably as if you were indoors. Soap and Fertilizer from Dead Locusts OCUSTS are plenti- ful in Uruguay and the farmers of that re- public are compelled to keep up a constant war against them. Millions of these destructive in- sects are killed every year. Recently it was learned that soap, ferti- lizer and lubricating oil may be obtained from the dead locusts, and in the future they will be utilized for that purpose. Removable This device protects the delicate plant from excessive cold, heat, rain, and wind A Soap Bubble Can Be Made to Last for Months HE air of an ordinary room is filled with tiny particles of matter which fall on the airy soap bubble, alter the surface tension, and—poof—it is gone, The effect of these minute particles on the stability of bubbles was first brought to light by Sir James Dewar. He ex. perimented in clarified air until he wag able to produce bubbles which lasted for months. He has even produced a soap film, which was a year old recently and which seems to remain just as it was made. So tell the children that the secret of successful soap bubbling is to have a perfectly pure soap-solution and to blow the bubbles in and with air that is also perfectly pure. Individual Protective Housing for Delicate Plants OR the protection of transplanted hothouse plants, Mr. John C. Mueller of St. Louis has invented a. device which: may be described as an individual pro- tective housing with hothouse and. irriga=- tion, features. The box-like. device with’ a slanting top is placed over the - plant: which needs protection and is secured by, pressing the lower edges of the structure into the ground. A removable top with strips of glass.and ventilated by holes ‘with raised edges, calculated to keep the rain-water from flooding the plant; is provided... If desired; a placed in the upper part of the housing, from which water may be plant. In case the growth of Extension, the: plant Supports should make a second or. Se story may be placed upon the original structure. met © MO Sa ess tO tf DB bt water tank may” be. slowly supplied continu- - ously to the growing: it needful,-. even a third ~ A bees, A. ee. ae | (66k ae

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Who Won the Motor Contest An interesting collection of labor-saving devices brought forth in the Popular Science Monthly’s prize automobile contest motor contest has been a huge success. The first prize of $100 goes to Mr. C. A. Butterworth of Newton Center, Mas- sachusetts; the second prize of $50 goes to Mr. P. C. Haas, of Ann Arbor, ‘Michigan. Both ‘prizes were won by young men in whom invention seems to be a cradle-gift, for neither makes his living as an en- gineer. It is significant that both prize- winners made use of the electric cur- rent to carry out their labor-saving ideas. Electricity is playing an in- creasingly impor- tant part in reducing the muscular labor required to drive the car. We have only to cite the electric starter and to contrast it with the old laborious hand-crankers to drive home the point; or to mention electric lights, turned on and off by a switch from the driver’s seat, thus elimi- nating the flickering oil lamp or the gas lamp with its leaking pipe; or the elec- tric water temperature controller which insures efficient engine operation as against no controller at all; or the elec- trically operated gear shifter as against the hand shifter; or the score of electric comfort-giving accessories. Mr. Butterworth, the first-prize win- ner, is a young man who has had no academic mechanical training and who has not even had a lesson in mechanical drawing. He has worked out an elec- trically controlled hydraulic gearshifter with an automatic clutch throw-out. It 6 hes PopuLAR SCIENCE MONTHLY’S PON *¥ = On the left, Mr. P. C. Haas, winner of the second prize of fifty dollars. On the right, Mr. C. A. Butterworth, winner of the first prize of one hundred dollars eliminates the physical exertion expended in the present type of car whenever it is necessary to shift gears. In addition, it does away with the physical labor re- quired of the foot to push down on the clutch pedal and to disconnect the engine from the driving mechanism when- ever the gears are to be shifted. It was our in- tention to publish complete drawings of Mr. Butter- worth’s invention in the present is- sue of the Popu- LAR SCIENCE MONTHLY. We find, however, that the time at our disposal is too limited for an ad- equate presenta- tion of the sub- ject. Hence we must ask our readers to wait for the July issue, in which full.justice will be done to Mr. Butterworth’s ideas. The winner of the second prize of fifty dollars, Mr. P. C. Haas, has inven- ted an electrically operated steering gear controlled by means of a small switch mounted on the steering wheel, retained for looks and for cases of pos- sible emergency. The task of guiding a car saps both the physical and nervous energy of even the most hardened driver. Mr. Haas’ invention, therefore, reduces the effort of merely following the right path by a percentage which cannot easily be calculated. It is our intention to publish Mr. Haas’ invention with full plans and specifications in the August issue of the POPULAR SCIENCE MONTHLY. Both Mr. Butterworth and Mr. Haas are to be congratulated on the success of their ingenious ideas. Maybe you have special needs. Write to the editor about anything within the Scope of the magazine. He will be glad to help you. 849

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asonee PTT To iad A One-Wheeled Motor Tractor A concrete illustration of how the difficulty was solved of making one wheel replace two HAT a _ one- wheeled trac- tor possesses certain real conveni- ences over a_two- wheeled affair has long been recognized, but the problem of working out the practical diffi- culties encountered were many and not easily overcome. The accompanying illustra- tions show an ingenious solution of this prob- lem, and give a com- prehensible demon- stration of how the various difficulties - were overcome. Some Steering wheel pinion Engine-starting f Heavy radiator acts as balance weight to engine Showing the interrelation of parts in the one-wheeled tractor, and its compactness of the problems encountered were the difficulty of trans- mitting the power from the engine to the driving wheel without a heavy and in- tricate system of gearing, of gearing down the engine revolutions in order to give greater power at the driving wheel, of providing means for changing the gearing as the conditions of load or Gasoline engine Steering gear 4 cyl Driving chain For hauling guns over narrow trails or broken ground this tractor would be better than army mules Exhaust line Clutch road might demand and, finally, of getting all these mechanisms into a compact space and of making it pos. ' sible for the wheel to turn a complete circle of three hundred and sixty degrees in order to meet abrupt turn. ing conditions. All of these prob. lems seem to have been solved in the one- wheel tractor shown on this page, the various mechanical _contriy- ances for power trans- mission and gear-shift- ing being shown in the diagrammatic picture, and the attachment of the trac. . tor to a fire-engine being pic- tured in another. The illustra- tion at the top shows how the tractor could be made to do its bit in the game of war by haul- ing guns over roads not passable by larger motor vehicles. The model has a four-cylinder gasoline engine, three-speed gears, a heavy radiator, and every part of the mechanism heavily rein- forced. The tires are solid rubber. tes nn ne te Gia os - ee “3 fit ris os 850 The old fire engine is attached to the tractor simply by changing from the pole and whipple-tree to a yoke i ee ee ee al

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eoot ©® 2S + — t. An Ideal Industrial Locomotive: No Smoke, No Steam, No Coal ITH coal scarce and gasoline high- priced and much in demand for all of our war activities, the oil-fired steam locomotive, burning heavy grades of distillate or crude oil, is now winning favor in plants where switching engines haul goods over short distances. The oil- fired locomotive has many uses. It is found hauling logs in camps far away from coal supplies; or wending its way on sugar planta- - tions; or busily transporting from the excavations for New York’s new subway system muck, rails, ties and ballast. Con- tractors select the oil-fired locomotive because it does. not pollute the atmosphere with smoke. In appearance, the fuel-fired locomo- tive, as shown in the accompany- ing illustrations, does not differ much from the familiar coal-fed type, except that a separate tank out in front of the boiler takes the place of the usual coal- tender. The cost of operation is said to be less than one cent a ton per mile. The construction is clearly shown in the accompanying cross-sectional view. The new industrial oil-fired steam locomotive in cross-sectional view. Popular Science Monthly Note the oil-tank in front of the boiler, which replaces the cumbersome coal-tender 851 Death Traps in Seemingly Unoc- cupied Fields at the Front HE precautions taken by the officers of the allied forces in order to pre- vent their men from falling into German traps during the excitement of an at- tack are brought out in a statement made by Major-General Charles M. Clement, of the United States Army, who visited the firing line in France. ‘‘When I studied army tactics some years ago,” he said, ‘“‘we had five points, represented by the five fingers of our hand, and _ there was nothing said about killing any- body. But an ar- my order today reads: ‘The object of this attack is (a) to kill the Germans; (b) to reach hill number so-and-so; (c) to stop at hill number so-and-so’; and woe betide the man who goes beyond the stopping point!’’ These explicit instructions were given, General Clement explained, because the enthusiasm of the French and British soldier frequently urged him beyond the objective; and fields back of that, which appeared to be unoccupied, often proved to be cleverly camouflaged death traps. > . Each part is plainly indicated, showing the compact construction of this coal-saving iron horse Those of us interested in science, engineering, invention form a kind of guild. We should help one another. All the specialized knowledge and information of the editorial staff of the Popular Science Monthly is at your disposal. Write to the editor if you think he can help you. He is willing to answer questions.

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A blotter boo for letters. They are blotted after being signed, by turning the leaves. This does away with the blurring of the signature when letters are turned over on one another Below is shown a six-sided ink-well holder made of paste-board, on which the calendar is printed age Ti BST ste AE Inventions to Re- duce Muscle Work in the Office A tray for checks and de- posit slips to keep them from becoming scat- tered while the clerk posts them A computing machine with seven adding wheels worked by hand with a pencil point A holder is shown below for small desk conveni- ences, such as clips, pins, rubber bands, etc. Six clerks, at this specially equipped table, handle 6,000 Pullman-car reservations daily In the circle is a loose leaf A railroad company uses this pass-book in which entries can itinerant bank to pay off be made by machine or pen 2,500 employees a month 852 T d g fT h t

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Do It by Aid of These Labor-Saving Tools and Machines Scales which reg- ister the accurate weight of shells anc shrapnel This electrically driven centrifu- gal milk sepa- rator is a great help in making tests of butter The upper cen- ter picture shows a belt conveyor for loading crushed stone, etc., into cars The center pic- ture shows a railway tie with a wood block and asphalt cushion base to take up shocks The portable ra- dial grinder shown below is used for general light grinding and buffing work An inspection bench with gages and devices | x for careful measurement of artillery shells The boring, reaming and facing machine shown at the left does accurate work on automobiles

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Sinking U-Boats with a Sub-Sea Barrage The Isham shell, which does not ricochet, is the latest destroyer of the submarine By Robert G. Skerrett HE diving shell is the latest thing for attacking hostile submarines. It is the depth- bomb improved and therefore more po- tent. Indeed, in the opinion of many ex- perts the diving shell is the most formida- ble instrument yet devised for battling with the foe’s U-boats. It is an out-and-out Ameri- can invention and the climax of years of study and development on the part of its originator, Willard S. Isham. Of depth-bombs there are several sorts, but of diving shells there are only two kinds—a foreign adaptation of the Isham missile and the Isham projectile, pure and simple. The reason for this is that the French and British governments have been more alive to the merits of the Amer- ican invention than our own ordnance officials, and, as a result, have actually been the first to apply the diving shell to wartime service. We are catching up, however, if reports from Washington can

High-angle firing makes the shell strike the water at such an angle that it will dive into the sea instead of ricocheting be accepted at their face value, and the so-called ‘‘non-ricochet shell” is likely soon to have its place in the magazines of all of our destroyers operating in European waters, High-Angle Fire and Its Drawbacks The British and French vessels that are armed to throw their form of diving shell resort to high-angle fire, the pro- jectile traveling a course much like that of a missile discharged from a mortar, In this way, the shell strikes the water at an angle sufficiently blunt to obviate ricocheting and to insure penetration into the sea. Once the missile has plunged beneath the surface its explosion is auto- matically regulated. The detonating fuse is set to operate at a predetermined sub- mergence as in the case of a depth-bomb. High-angle fire from a moving craft at an object in motion has a number of drawbacks. First, there is the com paratively protracted flight of the pro- How water enters cup and forms point

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jectile; second, its prolonged exposure whiie in the air to the deviating sweep of the wind; third, the fact that a slight roll of the gun platform will greatly change the arc of travel and, therefore, the range of the shell; and, finally, that the target offered by either the periscope or the conning tower of a submarine under way is a mark that is very hard to “range” accurately. Popular Science Monthly 855 ing shell now adopted.” And the same commission stated: “It would be highly desirable to have a high- explosive shell having a fuse such as has been sug- gested by Mr. Isham, viz, to detonate a shell on striking thin metal, such as the side of a destroyer, but which in striking water would not detonate until after a period of approximately a second—this in order that a shell which struck short of a ship might continue its run under water and explode on con- tact with the These points ras: li are mention- ed in order Since that to emphasize time, Mr. the advan- Isham _ has tages of the developed Isham type a fuse that of diving or he declares torpedo shell will do all which can be of the fore- fired over a going things flat tra- and more, jectory like ie., it will any ordinary explode after projectile a certain from a naval time, follow- gun. ing a dive, The Isham even should torpedo shell it fail to was original- meet an ob- ly intended stacle in its to attack the neue . path, and if nie ee ee ee ee thse body of an ai ‘ body, wheth- armored ship and thus to reach her vitals. In the invention’s present form we see a shell especially and peculiarly suited for battling with U-boats at long range even though the enemy craft offer but the smallest possible mark—the exposed tip of a periscope. Three years ago the Isham shell was tested by a board of naval officers, and while the fuse did not function satisfactorily in its entirety it showed even then that the designer was working in the right direction. The projectile, however, demonstrated that its author, by employing an unusual type of nose, could make the shell dive, on striking the water, and thereafter pursue a submerged course at a gradually in- creasing depth below the surface. It Dives and then Explodes The trial board reported that “a high explosive shell is an urgent necessity for naval use in addition to the armor-pierc- er thick or thin, it will burst within one hundredth of a second thereafter. When the projectile impacts with water the momentary checking of its speed fires a time element or “train” of powder which must be consumed before the flame reaches the primer which actually de- tonatesthe high-explosive bursting charge. If it hits either thin or thick plating, a per- cussion cap instantly sets off the prin- cipal mass of high explosive. Hydrostatic pressure does not interfere with the functioning of the fuse. The moment a submarine is seen from afar, the gun will be loaded with the Isham projectiles and hurled at the foe, the missiles forming a veritable subaqueous barrage and creating an under-water curtain fire one or two hundred feet short of the target, so that the shells may strike the body of the submarine and explode or, failing in this, be detonated like so many mines near by and wreck the undersea craft.

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Popular Science Monthly © Western Newspaper Union This apprentice machine is named after the penguin because, like that bird, it can skim along the surface of the water, but is unable to fly. It is safe for the inexperienced aviator The Penguin Seaplane—It Swims But Doesn’t Fly O you know what a penguin is? You may have read of it but probably have never seen one. The penguin is an aquatic bird found in the polar regions. It is remarkable for its peculiar structure. It has only small stumps in place of wings and, for that reason, is unable to fly. But it is a good walker and an expert swimmer and diver. The name of “penguin” has also been given to the training apparatus employed to teach prospective aviators the control of the airplane or seaplane. The name is well chosen. The penguin used for training is as unable to fly as its arctic namesake. It consists of an airplane with wings so small that the power of the motor is unable to lift the airplane off the ground or water. It is supplied with ailerons, elevator, rudder and wheels ex- ceptionally strong for running on the ground. The apprentice is en- encouraged to run this “pen- guin” to his heart’s content; there is no danger that it will take to the air. In a short time he graduates to a real air- plane that can and does fly, and then he can give all his attention to the flying part without having to worry over the handling of the various controls. The sense of safety he en- joys while learning is a great nerve- sedative to the inexperienced aviator. This Baby Caterpillar Tank Looks Dangerous But Isn’t HE miniature caterpillar tank shown in the accompanying illustration is not an instrument of war, nor is it in- tended to become one. It was made at the request of the Red Cross organization of Stockton, California, by a local manufacturer of caterpillar tractors, to be used as an attraction in a society circus, which netted nearly $10,000. The exterior of the tank was patterned after the English tanks used on the battle- field. A motorcycle engine was put in to supply the power for the motion of the track chains. It was so arranged that ; either side could be disconnect- ed or worked independently, thus permit- ting sharp A one-man tank built like one of the big English tanks, but intended for a less bellicose purpose ee i ee i ee ee, le ee ae eee | ee |} i

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Deep-Sea Fishing with a Little ; Submarine VERY fisherman knows that some of E the most desirable fish to be found in the ocean never run closely enough to the shore to be caught with line or net from one of the piers. These fish like deep water and the fisherman who wishes to catch them must go out to seek them in their haunts. That means a trip in a tug or a sea- worthy launch, which is not always fea- sible. F. H. Trimble of Los Angeles, Cali- fornia, has devised an original method of deep-sea fishing without leaving the shore or pier. He constructed a small boat, built some- what like a submarine, equipped it with a small motor run by a battery stowed away in the hold of the little craft and installed a simple clockwork that shuts off the current after a certain time. The little boat, built of steel and weighing about twenty-five pounds, is driven by a small propeller at about four knots an hour. It runs on top of the water or underneath the surface. To this boat two lines are attached. One line carries the hooks and bait, while the other line serves to pull the boat back to the shore or pier. The fisherman baits the hooks of his line, attaches it to the submarine and starts the little motor. The boat Popular Science Monthly 857 makes a bee-line for the deep-sea fishing grounds, taking the baited line with it. When it has reached the desired place, © Underwood and Underwood My son, you may go out to fish, but don’t go near the water Don’t go parachuting unless you are equipped with the proper kind of breeches the clock shuts off the electric current, and the motor stops. When the fisher- man thinks that every one of the hooks has its prey, he pulls in the line, hauling back to shore the boat and fish. Breeches for Parachuting N order to check the constantly in- creasing number of fatal aeronautical ac- cidents a humane in- ventor has patented a pair of parachute breeches. Will they prevent your being dashed to the ground? We don’t know. The fabric, cut, and work- manship are matters of choice, and your tailor will be pleased to suit your particular form and taste. For those who intend to be measured for a pair of parachute breeches in the near future, we give a list of instructions which should be followed when you find it necessary to use them: 1. Remove your dining-room table. 2. Lay the par- achute open on the floor. 3. Fold back the larger one and in- sert your legs in the smaller one. 4, Pull up and buckle trousers. 5. Adjust shoulder straps. 6. Tighten garters. 7. Gather all folds andswish them around to your back. Allow the train to trail on ground. 8. When you want to fly, give a quick jerk.

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Simplifying Sweaters One day a man got tired watching his wife laboriously knit a sweater. “Too slow, my dear,” he said; then went out and made this device. It worked so well that the gratified wife gave it to the Red Cross How Inventions an Machines Speed Up the Work of the Req Cross in New York Photos by Courtesy of American Red Croag A New Cutting Machine Cutting garments for war refugees, In the Red Cross workroom where this electric cutter is used 250,000 yards of cloth are cut each month, It will cut through some 209 thicknesses of cloth at once Making Clothes for Refugees Another scene in the Red Cross workrooms where garments for war refugees are made. The machine on the left is spreading cloth on ninety-foot tables at the rate of 1,000 yards an hour. On the right machines are shown cutting the cloth into garments Winding Wool on Bobbins A device used in the Red Cross model workroom for winding a hank of wool on bobbins so it can be handled easily when used on knitting machines A Measuring Table A table laid out in squares. Red Cross workers can be sure of mak- ing surgical dressings according to specifications if they use this first- aid chart for correct measurements ~~ A A ~~.

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And Make Easier the Work of the Devoted Women Who Take Care of War Sufferers Making Patterns _An electric machine which per- tes the patterns used by the fora Cross. ' The chalk, dusted through the perforations, makes an outline of the pattern on the cloth. Such strong material is used for the patterns that once perforated they may be used over and over again The Swift Winder An electric winder, known in the Red Cross workrooms as the “swift winder.” It wasinvented by a man who wished to assist his wife in her Red Cross work. As it is started and stopped by pressure of the worker’s foot on the pedal, her hands are free to guide the yarn A Sweater Machine A new electric sweater-knitting ma- chine which has found great favor in the eyes of Red Cross workers. It knits a sweater in 14 minutes Unwrinkled Gauze An ingenious device for folding gauze in required lengths. It keeps the material perfectly smooth so surgical dressings can be cut in accurate widths and lengths according to the requirements A Dressing Frame A frame which keeps light dressings in place. Workers can accomplish more work in less time by using this device be- cause their material is always where wanted at the moment when quick work is imperative

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The Hawks of the Royal Flying Corps What contact patrol means in the fierce fighting on the western front ONTACT PATROL—“A flight of one or more planes over the lines to give General Headquarters in- formation regarding the position of Allied and German troops and also to take of- fensive action against enemy troops on the ground.” The average reader who sees this definition probably concludes that contact patrol is as unin- teresting as it sounds. Defini- tions are never as thrilling as the things they define. Any fine morning on the sector of the western front held by the British you will find back of the lines of the gun. Under the fuselage are guys. pended several bunches of steel arrows; also two 100-pound bombs, or ten 20. pound high-explosive bombs. They Carry Bombs, Armor and Machine-Guns All these missiles of death are released at the Royal Flying Corps’ air- The turn of a lever dromes, preparing for contact patrol work. The airplanes used are squadrons of planes ‘leases a bomb. q P A slight miscalcu- lation means a miss generally of the same type (the [bkoperated \\ Steel f F.E.2.B. ‘‘Pusher’’), two seaters i with one hundred and twenty horsepower Beardmore engines. : While not particularly fast, these This 20.8. HE.Bomb shows the hook to which the planes are easy to handle. Be- pomb is cause their work is done mostly at a low altitude, they are slow climbers. It takes them about twenty-five minutes to climb ten thousand feet, but in straight- away flight they can do about one hundred miles an hour. With the motor throttled a contact patrol machine will glide sixty miles an hour, which is pos- sible because the plane has a nice gliding angle. The armament consists of one down- pointing Vickers ma- chine-gun, fixed along- side the fuselage or body and operated by the pilot, and one Lewis machine-gun operated by the ob- server. This Lewis gun can fire up or down and also straight ahead. The motor is in the rear, so that it cannot in- terfere with the firing Arrow release \ attached aviator from the observer’s cockpit by a bomb-firing trigger attached to a bomb-sight. This bomb-sight is not used on contact patrol, ag the airplane has to spend con- siderable time over an objective before it can be used. Ata given height there is only one point of space where the airplane must be, if the bomb is to hit its ob- jective. A miscalculation, no matter how slight, means a miss, When this happens, the aviator must turn his plane around and try once more to make the imaginary path of his machine pass exactly through the proper point. These repeated tricks are made for half an hour. The must maneuver at will, unham- pered by other planes. It is obvious that when the bomb-sight is used over a small area, a plane must fly at a high altitude luster.of steel arrows ™ A “contact airplane” armed for its arduous duties, with machine-guns, steel arrows, and twenty-pound bombs 860

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and alone. On contact patrol, planes fly very low and have done such effect- ive work particularly with their ma- chine-gun fire, that the Germans have found it necessary to dig bullet-proof trenches alongside the roads on which their troops march. At Popular Science Monthly 861 will be hidden in them with the result that perhaps one or more planes of the squad- ron will be brought down by their fire. Hostile ammunition and gasoline depots, headquarters, railway junctions, detrain- ing stations and aircraft hangars are V-shape formation. é Once over the lines, their work commences. They remind one of hawks hovering over a chicken yard. Eagerly the pilots and observers sean the ground below, undaunted by the hail arrows in the machine want to see most is a train or railroad or road-bridge. As soon as they see one, down they swoop. One after the other lets go a load of bombs and climbs again. The observers note the damage, etc. Suppose they see a regi- ment marching rapidly towards the front. In a fast glide, they descend almost on top of the startled soldiers. The machine- guns mow the Germans down, and often one plane of the squadron, flying higher than the rest, releases several clumps of the steel arrows. If there are no safety tren- ches at the side of the road, it is pos- sible that. al- most the whole regiment may be wiped out. Should there be trenches, no doubt Outer ring spring open, releasing the alarm, the regiments ial psc ol dive for these trenches iia a where they are com- ve Ari paratively safe. | | Generally five planes NAATAOVERCHOB AUR are assigned to a con- tact patrol squadron. Sitti They fly in the usual - wt ” all objectives for the pilots of a contact pa- trol squadron. It may be that there is a de- Metal tachment of enemy en- es gineers busily engaged in preparing the site for a new battery or building a bridge. If seen, rest assured that the planes will give them a warm reception. Submarine Saws for Water Weeds SUBMARINE saw is used to oflead poured up at them clear weeds from irri- from machine-guns and gation canals on the “Archies.” project of the United ’ ) “a These arrows, dropping from States Reclamation What’s That ? A weg a great height, "at yee tea Service at Orland, Cali- ment of Germans? able penetrative force, but a fornia. It is five-six- What the observers steel helmet affords protection teenths of an inch wide, one-fiftieth inch thick, and the teeth are spaced seven-sixteenths of an inch apart. It is made of special steel in flat, flexible, tape form and has toothed edges. Two men, one at each end, operate the saw by means of ropes, starting at the lower end of the section to be cleared and working up-stream. The saw is placed diagonally across the stream, one man keeping slightly ahead of the other. It is held at the bottom of the canal by iron weights placed atintervals of about three feet. To remove the weeds, planks are placed across the banks, about six inches above the sur- face. Slanting wooden pieces project into the water form- ing a grating o The saw, from 150 to 300 feet long, cuts the weeds; a which catches machine-guns wooden grating collects them and a rake removes them themown weeds.

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Soldiers operating a coal-gas-driven tractor and plow on an English farm tion of coal-zas for gasoline as a means of motive power for auto- mobiles in England. Tractors carrying balloon-like containers in which to store the gas are not uncommon sights in ‘Tt war is compelling the substitu- the fields, soldiers being brought from the front to operate the machines. But the employment of coal-gas is only a war- time expedi- ent brought about by the scarcity of gasoline and its high cost. With the re- sumption of normal con- ditions after the war it is expected that gasoline will again come into general use in Great Britain. The Brit- ish Govern- ment decided ~ in 1916 to re- strict the use of gasoline, following the English Farms poses. Plowing with Coal-Gas on The scarcity of gasoline combined with its high cost compels this wartime measure in Great Britain great demands made on the petrol supply of the country for war pur- Then the question of ob- taining an efficient substitute for gasoline came up. When coal-gas was being considered the difficulty of storing it had to be overcome, In early experiments gas com- and roped down. — Showing the tractor plow, with power furnished by coal-gas, plowing furrows in the soil of England A fresh supply of coal-gas being brought into the field on an English estate to operate a tractor plow 862 pressed in steel cylinders was employed, but there was trouble in reducing the pressure; hence the idea of a flexible bag to be carried on top of the vehicle wag evolved. This bag was globular in shape It was supplied with gas through a flexible sleeve, the connection to the engine being made by a tube with a con- trol-flap within reach of the driver. This method of storage has had consider- able popu- larity. However, the bag, like the gas it cantains, can be ac cepted only as a measure necessitated by the war, since it does away with metal cylin- ders. These are not prac- ticable be- cause of the great demand for metal. — oe O&: ot Ot Oe a leet: ot oklCU lee Om ete ee ee Gh (ee Oe Get itt oa ok CUCU hl lee ee CO lk atk

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—— — ov we” 8 aD 6s ss OF ' 4 Tunnel Is Coming. On with the Fresh-Air Mask OCOMOTIVE engineers of trains which pass through long tunnels or snow sheds often suffer from lack of pure air. The smoke and the exhaust gases pollute the stagnant air in the tunnel and make it almost suffocating. To remedy this Popular Science Monthly 863 The propeller is not situated aft, but amidships. The shaft protrudes through an encased slot in the bottom. The casing of the slot is proportioned so that, when the propeller is not needed, or when it drags bottom in shallow water, both propeller and exposed shaft can be lifted up out of the way of rocks and sand. The casing which is built along the center of the floor is condition an engineer of the Southern Pacific Com- pany invented a device which is shown in the accompany- ing illustra- tion. A funnel fitting over the nose and mouth of the engineer is connected by means of a rubber tube water-tight. The toggle- jointed shaft from the en- gine enters it at the forward end through a water-tight journal. The pro- peller and shaft are in- geniously brought in- board by a lever, the handle of with an air- pipe which runs to the main air reservoir of the air brake system. A small cut-out cock in the pipe permits proper regulation of the supply of air. Fold Up the Propeller When You Want to Row AVIGATING small motor boats in the waters of Hudson Bay and the contributory rivers is not easy. Shoals mean frequent portaging. The situation has stimulated a Canadian inventor to bring out a small engine for rowboats, the propeller of which can be lifted up into the boat by the twisting of a handle. In shoal water the propeller and shaft can be lifted out of harm’s way into a water-proof metal jacket The engineer in this picture regales himself with which is sit- pure air while his train runs through a snow shed uated con- veniently on the outside of the metal casing. The handle works a pivot which communicates with the inner side of the casing. This Isn’t the Only War Which Has Caused Prices to Soar N these days of tribulation, when everything rises but father’s wages, we all very consistently bemoan the high cost of living. But this is not the first and only time that prices have been high. During the Civil War wages ran from $1.12 a day for laborers, to $2 a day for skilled workmen. This, however, did not prevent a shave from cost- ing ten cents, or a haircut twenty cents. Hotel rates were $1.50 to $2 a day, and ice, which was considered a - great luxury, was supplied at fifty cents a week for ten pounds daily. Strangely enough sugar was the chief bone of contention in those days, too, and it cost twelve to fifteen cents a pound.

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eee ‘ 864 Popular Science Monthly This “zigzag platform”’ facilitates the loading and unloading of vehicles, making it possible to load and unload from sides and ends simultaneously, besides occupying far less space A Compact Zigzag Platform for Loading Wagons ET us introduce you to the zigzag- edge platform. Although its name suggests associations of Coney Island, it is a misnomer, for this platform was de- signed for use in staid mercantile pursuits. It will be employed, in fact, to facilitate the loading and unloading of vehicles. An excellent idea of the platform can be gained from the statement that its loading and unloading edge has a “saw- tooth” formation, the spaces between the “teeth” being large enough to back in vehicles. The “teeth,” or zigzag edges, allow wagons and automobiles to be un- loaded from their sides and ends, as the accom- panying illustration shows. The sides of the notches, of course, are at right angles to one another. In addition to the advantage of easy ac- cess to and from the sides or the backs of vehicles, the platform decreases the ex- tent of projection into the roadway of wagons, and apportions a defi- nite amount of space to each. This hoisting frame does away with the objectionable cleaning - pits in garages Getting Under Your Automobile by Hoisting It Up OT only makers and repairers but also private owners of automobiles will be interested in the hoisting frame for automobiles invented by J. A. Weaver of Springfield, Illinois. The accompany- ing illustration clearly shows the simple construction of the device. It consists of a rectangular steel frame, strongly reinforced and resting upon braced bases placed at right angles to the plane of the frame. Ball-bearing casters under the bases make it possible to move the hoist- ing frame easily from one place to another. The hoist- ing is done by one or two chains running either over the pulley in the middle of the top of the frame or over pul- leys placed in the corners. The chains are wound by a hoisting meéhanism operated by a worm drive. The device is strong enough to hoist with perfect safety any make of pleasure auto- mobiles. One great advantage of this device is that it requires little space. Sig bar era wh tio1 elal em) bar dail of : var sive the

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Signaling System Is Employed in American Barrage OME details of how the American troops in France lay down a parrage before an attack is made by infantry are related by Major-Gen- eral Charles M. Clement, U. S.A., who has returned from an inspec- tion trip to the front. A somewhat elaborate system of signaling is employed in connection with the parrage. This system is changed daily in order to frustrate the efforts of spies. The width of the barrage varies, and the fire is made inten- sive or light, depending on whether the men move backward or forward. This Submarine Raises Money Instead of Killing HIS is the story of a submarine 7. that invaded Scarborough, England, penetrating the very heart of the city without causing the loss of a single life. Furthermore, it was the means of helping to raise $500,000. It was at first planned to have an under- sea craft anchor in the harbor in order to spur persons to give to the fund. This idea being found impractical, a street- car submarine bank was built. The actual work consisted in transforming the vehicle into a submarine on wheels. The mem- bers of the crew shown in the accom- panying illustration are Scarborough “sea scouts,’”’ each of whom has been on vessels torpedoed by German submarines. Popular Science Monthly The cave probably marks the place where a boulder dropped out of the surrounding snow Nature Carves a Queer Snow-Cave in the California Sierras HE accompanying picture is a June snow-scene in the high sierras of Cali- fornia. During the progress of a govern- ment survey the engineers found the peculiar cave formation in the end of a bank of snow which was rapidly melting away under the rays of the sun. It is not known how the cave was formed, but it is believed that it contained a big boulder which, when it became warmer, dropped out of the crust of snow enclosing it and rolled down the mountain side. Forts Built by Vauban Are All That Remain of Ypres “T’HE only things left standing in Ypres after the German attacks are the forts built by Vauban early in the seventeenth century. This was one of the com- ments made by Major-Gen- eral Charles M. Clement, U. S. A., regarding condi- tions that attracted his at- tention on the firing line in France. He relates that in these damp forts two British commanders lived during months of warfare. It is queer that a seventeenth- century fort should survive This submarine took money instead of lives when it in- vaded Scarborough, Englani, to aid in raising $500,000 a twentieth-century bom- bardment.

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Teaching Machine-Gunners to Fire at Art How paintings worth thousands, the work of fa- mous artists, are used to develop skill in gunnery . By John Walker Harrington VERY war has called in artists to E help the fighters. Michelangelo, Leonardo da Vinci and Benvenuto Cellini did their bit in their time, and now come the Academicians of our own day, whose ambition it is to paint landscapes at which soldiers will be glad to aim either cannon or machine guns. These scenic targets are works of art in every sense, for they must come from the skilled hands of masters of perspective and atmosphere and must be so ably composed that they serve just as well as long reaches of hill and dale and rolling uplands. The Art War Relief, an organization which has been enlisting noted painters for this all- important work, announced that the canvases of students and amateurs were not available. Artificial Landscape Targets Most young men are city or town bred. - Hence few of the soldiers of our national army have a clear idea of distances in nature. As many of ‘the cantonments have not been placed amid scenery like that which marksmen are likely to see “somewhere in France’’ or ‘“‘on the way to Berlin,” artificial landscapes are pro- vided on which they can practice. The paintings are too valuable for cannon fodder or even for machine-gun feed, but they serve wonderfully well in giving the illusion of panorama. The series which have been painted by H. Bolton and Francis C. Jones, both veteran members of the National Academy of Design, are typical of the kind of art which is now in league with war. Some of these pic- tures were used by machine-gun com- panies at Camp Upton near Yaphank, L. I., before their departure for over- seas. Distance and Proportion As the machine-gunners ‘“‘lay on’’ their pieces in front of this pleasing mark they must keep in mind two things—range and close designation. The middle distance in the painting carries the normal vision back about 2,500 yards. The mountains far in the background are supposedly eight miles away and therefore out of range. The canvas is covered with houses and churches, bridges and culverts, and even a winding stream. The gunners aim their weapons at these various ob- jects. The commander comes up behind them and points out errors they have made in sighting due in part to their un- The aims of war are to aim so as to score. A faithful reproduction of a landscape gives the gunner a sense of distance and proportion not otherwise easily acquired 866 fo a aa i eee a Og: Oe. pale “bie ie. ete eee ee ee oe OO am, lk ni I es on ie! 6 ts . Vill ae oes

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Popular Science Monthly and of the interrelation of objects. trained eyes and in part to their lack of familiarity with the mechanism. How many men are there who grasp a description and act at once upon it? The officer gives the command, “Lay on black rock left clump of trees—three fingers!” Instantly the sergeant must repeat this order and see to it that the smooth barrel is so adjusted that it will guide bullets in the direction named. The quick under- standing of the description of objects in a landscape can be developed by the use of the imitation terrain of paint. The firing of ‘machine guns effectively is quick, sharp work and all the training of eye and brain which can be im- parted stands the soldier in good stead in an emergency. So exact are these high-art targets, owing to the co-operation of the military authorities and the designers, that even the complicated problems of strategy can be solved quickly by their use. Grain Field a ‘“‘ Nest of Death” After the marksmen have become more experienced they are assigned to devising ways for routing snipers out of hidden retreats supposed to be in all these mimic landscapes. The purpose is always to kill as many of the enemy as possible with the smallest amount of ammunition. Assume that there is in the center of one of the painted transcripts of nature a waving grain field, all golden in the sun, and en- veloped in a mellow haze, as an art critic might see it. The machine-gun captain considers it as a yellow nest of death in Machine-gunners learn from artistic reproductions of the terrain how to judge of distance Art with a capital A helps them to become experts the midst of which are certain big and deadly wasps, the stings of which are laying low comrades of another command. He cannot see exactly where the buzzing pests are straddled, but no time is to be lost. He gives the command to “traverse the field,” which means that his gunners so divide the whole expanse of nodding stalks among them, that the zones reached by the rain of bullets account for every square foot of the suspected area. The variation of fire is made by causing the individual gunners to tap their pieces gently, so that a difference of two inches at the end of a barrel becomes a large space with the widening angle reached in a distance of a mile or so. The method of tapping can be learned readily in front of one of the brush creations and a man who is quick of eye and hand may soon be- come very proficient. Useful in Estimating Trajectories The counterfeit countrysides serve just as well as the real ones in estimating trajectories of projectiles intended for a certain locality and in the mastering of much of the theory of gunnery practice. The mistakes of the tyro can be con- stantly corrected. As the canvases are becoming more and more exact in their proportions, they are considered already as among the indispensables. A British officer on seeing some of these examples of American skill at Camp Upton recent- ly, remarked that if the Allies had had as good ones they would have been able to have killed more Germans.

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Using his derby hat in lieu of a tripod in order to get a coveted photograph _ A Derby Hat Used in Place of Camera Tripod PHOTOGRAPHER desiring to make photographic copies of certain paintings in the Corcoran Art Gallery, wrote to the superintendent of the insti- tution and received the necessary per- mission, but upon ar- Popular Science Monthly Handless—And Yet He Is a Cham. pion Billiard-Player EORGE H. SUTTON, the veteran billiard-player, has demonstrated to the world that a man may become an excellent billiard-player without hands, Sutton lost both hands when a boy by coming in contact with a circular saw, This did not prevent him, however, from taking up billiards, first as an amusement and later, when he had acquired remark- able skill in the manipulation of the balls, to enter the class of professional “short- stops.” In a match game during the past season he made a high run of 113 in 18.2 balkline billiards. Sutton uses no attachment to hold his cue. By patient practice he has acquired such marvelous skill in the use of the flexible muscles on the stumps of his arms, that they supply him with a good substitute of the ‘‘wrist-movement” so essential to good playing. Many armless men and women have learned by painstaking practice to make use of their feet for writing, piano-playing, etc., but there are probably no parallel instances on record where a man deprived of both arms has become riving at the gallery he found that they did not permit tripods to be erected upon the marble floors. Not to be outdone, he used his derby hat, which, inverted and crushed in a little, bal- anced very nicely on the large mahogany rails in front of the pictures. Upon this he balanced his camera and, with a little care in focusing, using the rising front to give the proper per- spective, managed to get the long-time exposures required by the soft lighting. The scheme Photos ©) Int. Film Serv. worked perfectly and the copies de- sired were obtained. This method may be used for exteriors as well; but the photographer should be close at hand to look out for his camera in case it should overbalance. an expert billard-player by the use of his arm stumps. A seemingly ‘impossible feat— making a massé shot, holding the cue between his arm stumps Handless _ billiard-player George H. Sutton making a carom shot with bridge To eset oe et oe ct oes oss" a fr sat awit ase at eh tale tun a a Lh Ce

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He Outswims the Ducks in = =— = : His New Diving Dress “7 N a recent gray Saturday afternoon, in London, the fussy little tugs and launches were yi a “4 puffing about their business on ce . . —— the Thames, and every now and : YY = | then a lumbering Thames barge would pursue its un- beautiful bullying way down the river. The whistles were hooting, and a few gulls wheeled about, picking up scraps from the oily water—in short, it was just a regular, misty, gray London after- noon. Suddenly, though, there was a shouting and a cran- ing of necks, and the sleepy river life be- became immediately wide awake. A man had jumped into the river from one of the boats. Was it an at- tempted suicide? Had Popular Science Monthly Properly inflatea—but not with self-conceit—you can paddle yourself along com- fortably in this union suit. All you have to do is to in- hale as much air as possible, then exhale it through the tube into the costume. In other words buoy yourself up with your own hot air This shows a man properly equipped for a trip that is apt to lead him into a tem- porary sojourn in the water. The suit is air-tight, and if | he has enough breath left to inflate himself he can keep afloat for a long while he gone over to rescue some one? The The Service Stamp is the Latest black, murky waters swallowed him up. Patriotic Device He bobs up. The river men could hardly believe their eyes. He had reappeared N these days of rapid introduction of with a two-bladed paddle, and. was various kinds of new stamps it is not propelling himself along! It all proved surprising to hear of the service stamp. to be a demonstration of the new David- These stamps are made in sheets of one son life-saving suit. hundred with one, two or three stars, This costume is made on the same as circumstances require, and are de- principle as a diving-suit. It is both air- signed for use in the same way as the inflated and waterproof. Air-chambers Red Cross seals. The cost of a sheet of are provided in the body portion and in one hundred stamps is negligible. the leg portions, and these may be blown up by the mouth, through suitable tubes. The dress can be inflated in forty seconds. A belt around the middle, together with ad- justing the amount of air in the various chambers, serves to regulate the equilibrium. Affix one of these stamps to your let- ter, and thereby give your friend a hint that you have endeavored to ful- fil your duty to your country; it is bound to be a re- minder to him if in any small partic- ular he has been remissin that meas- The service stamp to be affixed to your . letter to inspire your friends with your ure of duty which own sense of duty tc flag and country weoweourcountry.

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Popular Science Monthly 2443. T7H141 8 An Alibi for the Bee in the Orchard HAT bees injure fruit is a common belief in some quarters, but investigations re. cently carried out in Italy prove it to be without foundation. Bees cannot perforate the skin of fruit, and the damage attrib- buted to them is really due to birds, wind, hail, hornets, wasps, an‘. certain other insects. Bees are, in fact, of much benefit to the orchardist, because they effect the cross-pollination of fruit trees. Mexican Corn Bins Look Like Old-Fashioned Sugar Loaves T first sight the objects that form the subject of our illustration look as though they were the twin spires of a Chinese women cleaning the cab windows of a Southern Pacific Railroad locomotive in Oakland, California Chinese Women Working on Rail- roads in California T is well known throughout the country that the people of the Pacific coast states take anything but kindly to Orien- tal labor. But at the present time there is such a serious shortage of white labor throughout the United States that even our Western brethren have sunken church. As a matter of fact they are corn bins on the Hacienda St. George, in Coahui- la, Mexico. They are construct- ed of adobe or sun-dried bricks, and are plastered on the outside. On the plaster landscapes are painted in bright colors. One of the bins, it will be noted, is sur- mounted by a cross. The corn is introduced through the little doors in the apex of the cones, and is taken out as required through the regular door. had to down their preju- dices and accept the inevi- table. The Chinese coolie has long been a factor in the labor market of the West, but as a rule his consort has held aloof from manual labor. Now, how- ever, a change has been wrought. Nothing could better in- dicate how serious is the shortage of white labor in that part of the country than the fact that Chinese women are now employed by some of the railroads on the western coast. Corn bins on a Mexican hastens shaped like sugar loatel but made of adobe or brick, and brightly decorated

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Wouldn’t This Puzzle the Enemy? A mine or torpedo that zig-zags under water to a zig-zag fashion, somewhat like a drunken man on the sidewalk, and which therefore makes a terrible nuisance of itself, has been invented by a foreign officer, a noted A MINE which travels under water in find its prey motion the chances of the mine’s hitting the objective are greatly increased. A weighted keel maintains the mine in the desired depth under the surface and also prevents its rolling. As it may sometimes be desirable to authority on mines and ex- plosives who is co-operating with the U. S. Government. The mine con- sists of two parts fastened together, but separated by a drive the mine at. a differ- ent depth, the keel is remov- able and may be supplanted by :@ heavier or lighter keel or fin, as the case may require. Any kind of wall. One of explosive may ‘the chambers, be used in this that in front, _ Tie mine, but the contains the sii es inventor fa- explosive charge and has at its forward end the contact trigger which explodes the charge when it hits the object for which it is intended. The other compartment contains the motor and a mechanism which alternately drives first one then the other of the two propellers, thereby giving to the mine a zig-zag course, but tending in the general direction of the objective point, while crossing and recrossing the medial line at oblique angles. It is the theory of the inventor that by this zig-zag The front part of the mine contains the explosive; the rear part the propelling mechanism and control 871 This picture shows the zig-zag path which the new submarine mine follows in its under-water course vors T. N. T., wet gun-cotton or dynamite, and also advocates the additional use of mono-nitro-naphthalene which, when the mine is exploded, gives off a dense black smoke, which will envelop the vessel struck and prevent signaling, repairs or rescue. As the presence of such a mine in the water constitutes a constant danger to shipping, provision is made to cause it to sink after a predetermined period. A timing mechanism opens a valve in the rear end of the mine, allowing Seacock the water to enter. The Launching tackle _ Switch for weight of the water causes Ti marian) operating motor the unexploded mine to sink wate to the bottom, preventing accidental discharge. To propel the mine, each propeller may have its own motor, and the motors work alternately, or there may be but a single motor, the power of which is applied alternately to the propellers by an oscillat- ing gear or otherwise. The invention permits of many non-essential variations.

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872 Worse Than the Shinplasters of Civil War Fame CURIOUS condition of affairs with respect to money prevails in the department of Narino, the southernmost department of Colombia. This region is isolated by poor means of communi- cation from thecen- tral government and has regulated its own affairs to a great extent. When the rest of the country adopted a gold standard Narifio refused to conform and en- forced a local silver standard. As it accepts at silver value coins of all nations and dates . it has become a dumping - ground for coins no longer current. elsewhere. It is said that the most abundant coins are the old eight-real pieces of the early years of independence. A few years ago, we may add, the whole of Colombia was swamped with paper currency enormously de- preciated. At one time it took 22,500 pesos of this paper to buy a United States gold dollar. The government has now issued a decree recalling the national silver coined before 1911 and all foreign money now in circulation. Popular Science Monthly He is not a millionaire’s son. Colombian paper money is worth just one dollar. A paper peso is worth one cent how much farther it will shoot north than south, and to what extent the moon will de. flect theshot. Asaresult, whatis described as the ultimate error of the cannon shot jg being rapidly overcome. Moreover, if g commanderis unable to point a cannon with- in ten feet of the target, heis not re- garded as asuccegg, This Is a Farm Gate, No Doubt ERHAPS it was his pas. sionate love for farming, perhaps a dawning sense of art, or pride in the paternal acreg which had come down to him through many gen- erations of tillers of the soil, that in- duced the owner of a farm in Moulton, Northampton, England, to put the quaint gate shown in the accompanying picture at the entrance to the driveway leading to his farmhouse. Anyone who passes All this ‘that gate will know that the owner of the estate is a farmer and so proud of it that he wants everybody to know it. The orna- mentation is, to express it mildly, original in design and of striking appearance, but does not betray a high degree of artistic taste. However, it is symbolic of the farmer’s calling, and who shall criticize? Moon and Earth Help French to Aim Cannon HE French engineers in the European war have reached a high degree of perfection in mathemat- ics, according to Major- General Charles M. Clem- ent, U. S. A., who made an exhaustive study of con- ditions on the firing line. These sappers of the French army have figured out the in- Cire es ‘ My Ds he ings” B ios - rat es tS lg tne ong abe aoe . - eos Se ieee ee ee fluence of the earth on ashell traveling out of a cannon, An English farmer has decorated his gate with the various implements of his calling. If not artistic it is surely symbolic nipinassinhoveipiii mat } @ © er chr oo wet met oe © Fr ht oD 88 lB eek Oe = 4B 89 Oe BO re at oF et 45 SA Of © BD WD of wy ™~ bette pw

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a sree Popular Science Monthly The boilers con- tained enough air to keep them afloat while they were towed ashore. They were then en- and started for China for duty. in another ship How the Boilers of the ‘‘Bear”’ Were Salved HE steamship Bear of the American Geodetic Survey stranded near Cape Mendocino, on the California coast. When it was found impossible to save the ship all efforts were confined to the salvage of the valuable contents, including the boilers and machinery. The machinery was taken apart and conveyed to the =A beach piecemeal. The large boilers, how- ~ ever, six in number, could not be taken to pieces, and their salvage was therefore attended with great difficulty. Each one of the boilers was eleven feet six inches long, thirteen feet six inches in diame- ter and weighed fifty-one tons. Each individual water tube was first The ship could not be saved, but cargo, boilers, and machinery were taken out | of planks, then set afloat again and towed twenty-five miles to Eureka, California, whence they were shipped to Shanghai to be placed in another hull. A Lilliputian Rival of the Popular Wrist Watch F the ponderous old grandfather’s clock, with its weights and wheels, could do so, it would doubtless raise its hands in surprise at sight of the ring watch, the smallest member of the time-keeping family. This tiny record-keeper of the minutes and hours adorns, and is adorned by, a finger-ring studded with jewels. It is shown in the accompanying illustra- tion. This watch is a composite timepiece, the works being of Swiss manufacture, and the case of New York make. The movement is smaller than a ten-cent piece and the case is studded with diamonds, even the winder plugged at each end to make it airtight. The air: enclosed in the pipes and in the boiler was suffi- cient to keep the boilers afloat after they had been lifted out of the ‘hold by a derrick and deposited in the water. The boilers were rolled being set with one of these precious stones. Asa novel and attractive or- nament this little watch is pretty sure to find favor with the fair sex, and it is possible that it may to some extent re- place the wrist watch which has recently gained so greatly in popu- onthe beach, en- cased in an armor This little watch on milady’s finger ring is a real, honest-to-goodness timekeeper larity, especially among soldiers.

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The First Step Captain Derwent Wood, an English sculptor, has worked out a method of covering disfiguring scars by metal masks painted in life-like colors. The meth- od is not new, but has been greatly improved by the sculptor. The first step toward restoring the patient’s features consists in making a plaster cast of the parts to be covered by the mask. This isa great boon to the disfigured fighter, although he may well be proud of his scars The Rough Cast The masks are made by an electrolytic deposit of pure copper upon a cast of the features as they are intended to appear. They may also be made of silver or of some alloy of silver and copper. In the pic- ture Captain Wood is examining the roughly molded mask before it is trimmed, adjusted and finished by enameling and painting. Great skill is required in order to match perfectly the lineaments and complexion of the uninjured side of the face Almost Finished The thin metal mask, having been carefully fitted and trimmed to the proper size and shape, ig enameled and painted to match the color of the patient’s skin. The pic. ture shows Captain Wood with the almost finished mask in his hand, about to adjust it to. the features of the patient before him, The means for fastening the mask are still lacking Ciiccddlccddddd, Uldddddddddiddddmiddddgaawiike Lu cledltedddddealleohe a ae SOO QNOO MWAH. Add WR RAWWWW WWW DW Photos © Underwood and Underwood The Finishing Touch After all the preliminary work is done and the mask fully completed and pro- vided with the means of fastening it, the patient puts it on and the sculp- tor, who is also a painter, puts the finishing touches to his handiwork. One of the most difficult prob- lems is to obliterate the tell-tale border line where the mask and the skin meet. This is done by careful retouching of the painted surface. manner of holding the mask in place depends upon the conditions in each individual case. In this case it is held in place by a pair of spectacles

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Covering Them with Artistically Shaped Masks Mddsdlddddddldlddddlbldddlldddddllddhdllddddddkkdrdxrdvrsy

Only Imitations The _ stock-in-trade of this human repair shop By , ; is of a varied nature. A Shell’s Work g : 4 Masks in every stage of ag , 4 completion, ears, eyes, Although t A page seid G : 4 ; ‘ noses, chins or other Cage ine 4 to weet a y of the features are means ee ; apes e€ most common speci- injuries, ca — a j — in — Spec- oO r acles are often em- who were dishgured hed ployed as a convenient ae S avedin anmee. —_— of —— j I astening e meta The picture thors pi masks so as to cover the a young aman rod disfiguring scar caused a tape Splinter. by injury or disease transforma- tion wrought by the mask, in the picture to the right WN RRR WW e>ooe Mh, Wo

With the Mask The picture above shows the British soldier of the picture on the left, as he appeared wearingthe mask made for him by Captain y ’ Z Wood. It is held in place Z by the spectacle frame A Sculptor’s Idea j eat and completely hides the j : terribly disfiguring scar The officer shown stand- j which the shell-splinter ing oe hen picture, palette y wound left between the Francis. a dg > ; ‘ ae | young man’s eyes. It is he Eneli ’ . Sarr Z so perfectly made that it is the English sculptor, who j c ; almost impossible to see enlisted M. y os é where the oe ends and army in May, is e j ae ; y j ; i entered the hospital serv- — ‘ 1. “oy the natural tissue begins ice and soon was placed in y : charge of the splint room of one of the military hos- Ppitalsin London. His ex- Perience there suggested to him the thought that art could be of great help in extending and perfect- ing the efforts of plastic surgery. The govern- ment encouraged him and he was given an opportun- ity to develop his method

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a ee Popular Science Monthly Formerly it took ten men Wafting Five Tons About as Though They Were Thistledown ( “ ALL ready below there?” “Yep, let ’er come.” , There is a whirr and the rattle of a running chain, and a huge packing-case floats airily out of a second-story window and smoothly descends towards the flat-car which is waiting below to receive it. “Easy now—bit further—whoa!— back a bit—a-a-all right.” | That is. about the sum total of the operation of loading a packing-case con- taining five tons of motor-truck onto the cars for shipment, at the plant of one of the big truck manufacturers in Michigan. The reason for the ease with which the thing is done is due solely to an ingenious bundle-carrier that the company has installed. There is nothing very new in its essential parts, for it is the regular chain-and- pulley type of purchase, but the application to special conditions is very interesting. The track on which the lifting tackle travels is extended across The lifting tackle travels on a track extended from loading room across track. One tackle performs the operation ome a Whole ten-hour day to do me| a single job, and inclineg *%| planes had to be built to “| load the upper boxes: from using rollers and crowbars, Now four men can load about forty-eight boxes a day, and, if necessary, one man doesit, This Moving Van Loads From the Side OUSEHOLD goods and pianos, as well as other |)‘ things that had to be moved “| for some considerable dis- tance, formerly went by railroad. Recent railroad congestion, however, and the difficulty of getting box-cars for anything that does not come under the head of war necessities, has brought home to many people the fact that it is often cheaper and handier to have their household furniture moved by vans. Even if it did cost a little more, there is a great deal gained in convenience, because the goods are actually taken right out of your own dwelling into the same van that con- veys it to your new abode. But as a mat- ter of fact, it is actually cheaper in many cases than to pay freight plus cartage. As an aid to dispatch, a Los Angeles, California, moving man has equipped his truck-van bodies with side-moving doors that make it possible to load heavy pieces of furniture, such as pianos, right onto the van from the sidewalk. Formerly special tackle had to be used for doing this, so it is evident that a considera- ble saving in time and labor is effected. eo the track and into the oo a fis loading room too. Conse- quently the cases are moved around, swung out, lowered, and everything is done with the same tackle. Four boxes are loaded onto one car. Showing a side-opening arrangement whereby heavy goods can be loaded without aid of special tackle er

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Popular Science Monthly © Int. Fitm Serv. -. Uncle Sam’s embryo soldiers obey the call to go “over the top” with all the will in the ° world—fit for a fight or a frolic as fate may dictate when they get “there” Going ‘‘Over the Top” with the Learning to be a Blue-Water Sailor Soldiers at Camp Upton on Dry Land HE accompanying photograph shows HE training of a man-of-war’s man what the camera registered when is not a simple matter. In days gone the photographer took a snapshot of by it used to take almost as many years soldiers at Camp Upton while they were as it now takes months. The methods of going “over the top’”—which is only one instruction and of training have under- feature of the physical training which the gone wonderful changes; they have be- Camp Upton men undergo in preparation come much more intensive and to the A class at the naval training station ~ at Newport studying the various parts of a ship for the fighting “over there.’’ Punching point, and the results obtained prove a bag with a bayonet te accustom the _ the efficacy of modern methods. soldier to hand- —ae Stations for the to-hand struggles, 84 ; y training of the fu- foot races, boxing ture sea-fighters matches and other. 3 - have been estab- sports make up ais ra ec® Sone «ON lished at many their life in camp. points. At these ' ne stations the young WY) Lee cny Hy men _ preparing ~~ a ee themselves for en naval service re- Photos @) Western Newspaper Union ceive the most careful instruction and training, theoretical as well as practical, and in accordance with the most advanced ideas. Nothing could emphasize more strongly the difference between the present method of training and that which was in vogue in the olden days. Then the men were drilled in the most primitive manner; a rope’s end usually played an important réle as an educational factor. Now, with the help of models, the men are taught in Tien one hour what would have taken The science of “boxing the compass” is taught to days, weeks or even months the naval recruits by aid of this ingenious device under the old system.

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LEXIBILITY of operation is the great outstanding factor of power transmission by means of fluids, so far as the automo- bile is concerned. Fluids transmit power through the pressure exerted by the fluid on the part to be moved. -\The fluid is pumped by some means into cham- berscontaining the parts to be moved, and since the fluids used are practically in- compressible, the degree of pres- gure exerted is al- most proportional to rate of flow or the pressure rep- resented by that flow. It isa simple matter to change the pressure by merely changing the rate of flow. This may be done by ordinary control means and gives such a wide range of different speeds that when a hydraulic transmission is applied to an automobile, the latter can be run at the speed best suited to the condi- tions of load and road instead of the three or four speeds provided in the or- dinary sliding-gear transmission. The hydraulic transmission sup- plies those speeds which the gear re- duction cannot be- cause the number of teeth in the meshing Driving Your Car Through a Stream of Oil This new transmitter solves the dual prob- lem of power-waste and leakage of oil same. Parts of Power Transmitter When engine is started, the blades of member at- tached to engine force oil against blades of housing mounted on propeller shaft, turning this and finally rear wheels. The oil flows back into a chamber at inner circumference of two housings, whence it again reaches blades of engine member, thus continually circulating within housings. Gentle flow eliminates the jerks caused by the clutch in ordinary cars of the oil. Showing the installation of a tur- bine as a substitute for the clutch 878 gears necessarily always remains the Again, the hydraulic transmission enables the pressure to be increased grady- ally from low to high speed. [It also eliminates the clutch and does away with the at- tendant manual effort when chang. ing speeds. The hydraulic transmission’ of power in motor vehicles is not new, In some of the sys- tems used a mas- ter pump is driven by the engine, and other smaller pumps drive the wheels, the oil reaching and leay- ing the smaller pumps through a series of pipes, Most of the pumps consume an ex- cessive amount of power because of skin friction in the pipes orleakage Sometimes both of these factors are combined. Both of these difficulties seem to be solved in the power transmitter, which consists of a com- bination of a cen- trifugal pump anda turbine that can be inserted in place of the clutch in any car equipped with the ordinary gasoline- engine of .the pres- ent day. Thereare no pipes. Nochanges need be made i the other power transmitting parts.

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Popular Science Monthly The turbine consists of but two mov- . ing parts, a driving member attached to the engine-shaft and a driven member, fastened to the front end of the propeller- shaft of the car. Both members are con- of two circular housings with plades or fins radiating from a central rectangular cham- ber. The two members stand apart and touch only at the bearings on the shafts. The space inside the housing is par- tially filled with oil. When the engine of the car is started, the blades -f the member attached to the engine force the oil up against the blades of the housing mounted on the propeller shaft so that it, and finally the The spring keeps the feed bag adjusted so that the horse can get at the oats thrown out of contact with the flywheel if it is necessary to shift the gears in the usual manner. As long as motor-driven vehicles are used, the quest for im- provements and labor- saving devices will go on, stimulated partly by economic dictates and partly by the inherent inclination in the human race to simplify me- chanical contrivances. “Strangler” Lewis, the famous wrestler, uses the dummy for exercise 879 Making It Easy for Old Dobbin to Eat Out of the Feed Bag HE feed-bag support invented by William Meier of Jersey City, N. J., structed exactly alike and are made up is designed to overcome the difficulties invariably connected with the use of the feed bag. This bag is provided with a spring so that it will adjust itself when the food gets out of reach of the horse as it diminishes in quantity. Even under the most favorable conditions part of the oats will be spilled in the horse’s attempts to get at it. Mr. Meier’s invention consists of a yoke-shaped frame of heavy spring wire, which is suspended from the head and neck of the rear wheels are turned to make the car go. animal in the manner shown in the il- The speed of the car is controlled by the lustration. The bag is suspended by a cord throttle, although the device may be running through a loop of the spring. Practicing the Head-Hold with a Wooden-Headed Adversary OXING with a dum- my which can’t be knocked down is a well- known and _ recognized form of training for pugilists, but hitherto wrestlers have been rather unprovided for in this respect. Now, how- ever, Mr. B. C. Sandow, of Rochester, New York, has brought out a dum- my head to train a man to give enormous pres- sure in the head-lock. This apparatus is a wooden, life-sized head, made in two equal pieces divided down the ‘center of the face. Thehalvesare kept apart by three coil springs. The wrestler practices squeezing the halves together, as he would in the head-lock, until he can conquer the tension of the springs.

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A great cooker for campers, and a boon to the housewife in summer You Can Carry It in Your Hand and It Saves Fuel JT is expensive as well as un- comfortable, in warm weather, to use a gas oven when the same result can be obtained by using one of the burners on the top of the stove. But how can you roast on such a burner, you ask? The answer is found in an effi- cient cooker which has recently made its appearance. The new cooker, built of cold rolled steel, consists of six parts—an asbestos- lined hood, a base with a removable heat deflector (also asbestos-lined), a perfora- ted corrugated circular steel plate which acts as an equalizer for the heat, and a wire stand. Extra strength is obtained ce Popular Science Monthly V\ CT TT Titi t pa No Footprints Are Left by the Gasoline Lawn-Mower tiger lawns of the golf-club need trim. ming and the horse-drawn mower has been at work since early morning Up the gentle slopes and down again pea the other side old Dobbin is pulling the heavy cutter. When the blades of the mower encounter thicker grass, Dobbin slows up and the increase of resistance caused by a little hummock is sufficient to make him stop altogether, until sleepy “‘Gidap” from the driver stirs nim to a renewal of his labor. Streaks and holes appear at intervals, which ip. variably cause dissatisfaction on the part of the golfers. Because of Dobbin’s inefficiency ; western country golf club decided to purchase the converted Ford motor !awn-mower shown in the accompanying illustration. It leaves no hoofprints, does not tear up the sod and pulls with such evenness that the grass is almost as smooth as the top of a billiard table. Besides, it does the work of two horse teams and at a smaller cost. The tractor. consists of a reg- ular Ford runabout model with wide metal wheels in the rear, It is run on second gear when pulling the mower and is provided with a water pump to circulate the engine water properly at the continuous low speed. To prevent the water from being spilled out of the radiator when the tractor is going down sharp inclines, 9, gallon can it attached to the radiator cap as shown in the accompanying illustration. — a N corners of the base and hood are folded When used as an oven the cooker bakes perfectly. It is large enough to bake two loaves of bread at once, a fowl or enough of any food sufficient for the din- ner of an average family. The equalizer, used without » “7, the hood, is of great assist- > ance in cooking or frying in the manner in which the ‘7 Pas. as it spreads the heat evenly Hitch your Ford to a lawn-mower and you will securea velvety lawn without giving a horse nervous prostration under the pot or pan.

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When the Moon Darkens the Sun What astronomers will look for during the June total eclipse of the Sun By Calvin Frazer of the most awe-inspiring spec- tacles in the whole repertory of Nature. Its overpowering effect upon the human mind is illustrated by an episode which the present writer recalls in connection with the eclipse of May Att tte eclipse of the sun is one light on a wide range of scientific prob- lems. Hence, in order to observe a proc- ess of Nature lasting generally only two or three minutes expeditions are or- ganized and equipped at great expense, and sent perhaps halfway ’round the world to some favorable vantage point. 28, 1900, as seen at Norfolk, Vir- ginia. The weather was superb, and the town was crowd- ed with visitors; besides whom the natives were all on the streets. During the period of about an hour following ‘first contact,’’ while the disk of the moon encroached more and more upon the face of the sun, the spec- tators, white and After arrival, many weeks are spent in setting up and ad- justing instruments and rehearsing every detail of the observations, so that the advance program may be carried out with- out a hitch at the proper time. Every precaution is ta- ken to economize to the utmost the precious seconds available during the event. black, kept up a lively chatter of conversation. Probably most of phenomenon rather tame, and wondered why people should travel miles to see it. Just be- fore the beginning of totality the light of day faded with startling abruptness, the beautiful solar corona flashed out, the stars appeared in the sky, and a ruddy glow, as of late sunset, encircled the horizon. The babel of conversation ceased instantly, and was succeeded by the crash of breaking glass. Totally un- prepared for so marvelous a sight, many people, especially among the colored population, let fall the pieces of smoked or tinted glass through which they had been viewing the eclipse! Interesting to the layman as a spec- tacular event, a total solar eclipse is even more interesting to the astronomer as a rare opportunity for obtaining fresh Renewed efforts will be made at the com- ing eclipse to solve the mystery of the flickering “‘shadow bands,” which steal over the ground at the beginning and end of totality. Former attempts to photo- them found the graph these “flickerings” were not successful 881 After all these preparations, the astronomers in many cases get no results at all, ow- ing to unfavorable weather. A single cloud may blast their hopes. The party sent from the Lick Observatory to view the eclipse of 1900 encountered a citizen of Georgia who was frankly skeptical about their ability to foretell the occurrence of the eclipse, and his doubts deepened to positive dis- belief when he heard the observers anxiously speculating about what the state of the weather might be on the eventful day. ‘‘These young men,” he said, ‘‘try to tell me they know the sun is going to be eclipsed, and they can’t even tell whether the sky is going to be clear!’’ Unfortunately the only help the mete- orologist can give to the astronomer in this matter is to tell him what the average weather has been in previous years on the DMs. a

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The Sun’s Glorious Corona in Total Eclipse Photograph by Yerkes Observatory When the Moon Masks the Sun’s Face Only during the fleeting minutes of a total eclipse may the Sun’s weirdly beautiful Corona be seen. It is a pearly white glow, like a halo, which extends in an irregular outline millions of miles into space. Photographs will be made of the Corona, as usual, to determine its size and outline, which varies a 882 great deal from one eclipse to another and appears to be related to the frequency of the sunspots. It is hoped also to obtain good cinematograph pic- tures of the total solar eclipse on June 8, 1918, and many problems hitherto not accurately determined are expected to receive clarification at this time. Mn, o “uz cts © & s+ p08 Oo Ret O's 577) t u 0 b h u T=

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nese E Teyana te date in question, and such information always plays an important part in the selection of sites for eclipse observations. Generally speaking the chances of favor- able weather are best along a line from eastern Oregon through Idaho and Colo- rado, and this will be a favorite part of the track for the further reason that the sun will be higher in the sky at the time of the eclipse than farther east. The world over there are about 70 total eclipses of the sun in the course of a century, but at any one place on the globe there is, On an average, only one in about 360 years. In the whole present territory of the United States (outlying possessions not included) there were only eight total solar eclipses during the nine- teenth century, and there will be the same number during the present century: viz, in 1918, 1923, 1925, 1945, 1954, 1979, 1984 and 1994. A Case Where the Moon Obscures the Sun The fundamental facts relating to a solar eclipse are quite simple. The moon, in her monthly revolution around the earth, occasionally passes between us and the sun. The moon has no light of her own, and when she shines it is by reflected sunlight. In a solar eclipse her unilluminated side is turned toward us,‘so that we see her as a black disk, intervening in front of the sun. The reporters who write up scientific events for the newspapers often refer to this disk as ‘‘the shadow,” through confusion The principal heavenly bodies, which will be visible near the sun during the eclipse. Although many astronomers have given up the hope that any planet or planets moving within the orbit of Mercury, the planet nearest the sun, will ever be found, the search will be continued during the coming eclipse Popular Science Monthly 883 with eclipses of the moon, in which the darkening is due to the shadow of the earth. What we see is not a shadow, but the moon itself. The sun’s diameter is about 400 times as great as the moon’s, and the sun’s average distance from the earth is about 390 times that of the moon. he attached diagram, which is correctly drawn to scale, shows the long, tapering shadow cast by the moon as she revolves through space, and shows why there is only a small area of the earth’s surface from which, at any one time, the sun is completely hidden by the moon. Owing to variations in the distance of the moon and the length of her shadow, there are some eclipses in which the latter does not reach all the way to the earth. Under these circumstances an observer directly in the line passing through the sun and moon sees, at the time of eclipse, a circle of sunlight extending all around the lunar disk, and the eclipse is said to be ‘“‘an- nular.”’ The Moon’s Shadow a Fast Traveler ~ Theshadow coneon June8 will first touch the earth at sunrise in the Pacific Ocean, not’far south of Japan. Thence it will sweep eastward, entering the United States in southwestern Washington at 2:55 P.M., Pacific Standard Time. It will then be traveling at a speed of 33 miles a minute. Striking southeast, it will cross the Mississippi River at 5:37 P. M., Central Time, reach the coast of Florida at 6:42 pP.M., Eastern Time, and leave the earth after reach- ing the vicinity of the Bahamas at sunset. The actual time re- quired for: the journey across the United States (from 2:55 P. M., Pacific Time, to 6:42 P.M, Eastern Time) will be 47 minutes. ‘“ Day- light saving” necessi- tates the adding of an hour to these times. The coming eclipse will be observed by par- ties from all the leading observatories of Amer- ica. But for the un- happy state of public affairs abroad, we should SS Se

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Popular Science Monthly o— EARTH MOON'S SHADOW “> = —> DIRECTION OF guy MOON ; This diagram, drawn to scale, shows the earth, the moon and the moon’s shadow duri the eclipse. The distance of the sun is 390 have -had the privilege of welcoming scores of astronomers from Europe. One large American observatory—the Cham- berlin. Observatory, at Denver—will not need to send out an expedition, as it is situated right in the path of +totality. The unusual length of this path within accessible territory is a particularly favorable circumstance, for the reason that observers at western stations, after viewing the eclipse, will have ample time to telegraph to those at eastern stations, calling attention to any features that especially demand further observation. By hiding the sun and cutting off the glare of sunlight in our atmosphere, an eclipse makes it possible for us to see the envelope of incandescent gases by which the sun is surrounded, known as the chromosphere. Beyond the chromosphere, and extending millions of miles into space, is a pearly white glow, of irregular times the distance between earth and moop-: outline, known as the corona. By means of a marvelous instrument called the spectroscope astronomers are able t see and to photograph the chromosphere and its prominences at any time; but the corona can never be observed ‘except during a total eclipse. The spectroscope is also applied, while an eclipse is jp progress, to a study of the chemical composition and the movements of-thege solar envelopes or atmospheres. Ba In past eclipses eager search was made, by photography and otherwise, for’, possible planet, or planets, lying within the orbit of Mercury—the nearest to the sun of the planets now known—and ob servations of an “‘intramercurial planet” were occasionally reported. These ob servations were, however, undoubtedly erroneous and astronomers the world over have generally given up hope of find. . ing such a planet. * ber) ad 108 a BAe? ae ~ 4 e te YAZOO city } About eighty-five towns are directly in the path of the total eclipse. Since we are saving daylight add an hour to the times on the map. The track of totality extends from WashingtontoFlorida. Outside of this track, in a belt varying in width from seventy miles at its western end to forty-five miles at its eastern, a partial eclipse will be visible Ph é J ( ¢ , ¢ (

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Popular Science Monthly Photograph by Yerkes Observatory Great masses of glowing hydrogen are tossed up as far as three hundred thousand miles from what is called the ‘“‘chromosphere,” an irregular scarlet rim which will be seen surround- ing the moon’s disk. This rim, however, can also be studied even when there is no eclipse Scientists Will Test New Theory During the coming eclipse the region around the sun will be most carefully photographed for another purpose, and one which constitutes a novelty in eclipse observations. According to the new theory of relativity, which is now exciting so much discussion in scientific circles, there should be a very slight dis- placement in the apparent positions of stars seen close to the sun, owing to an attraction exerted by the latter body upon beams of light passing near it. This displacement will perhaps reveal itself on the photographic plates. Other new features to be observed will be the effects of the moon’s shadow on radio signals and the presence of electric waves in the atmosphere.

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886 Something to Lose Sleep Over— Can Fish Hear? AN the humble minnov, or any of his larger brethren, hear? He has ears, but are they any use to him? Some scientists have experimented and said ‘Yes!’ while others have experimented and said “No!” However, recent study seem to indicate that fish do hear. Some of the fish experimented upon had their ears removed, and others had their skins made insensible. Then sounds were made in di- rect contact with the water, but without agi- tating it at all, and signs of hearing looked for. It was found that fishes are influenced by sound. One of the most peculiar and striking manifesta- tions was the fact that a fish that had had its hearing organs destroyed lost its sense of direction when swimming fast. It could swim straight slowly, but as soon as it attempted to put on speed it went round in spirals. Con- sidering that many species of fish travel considerable distances during their periods of breeding and depositing their eggs, such loss of direction would tend to make them easy prey for their enemies. Crowns On Their Tails. The Queer Forms of Some Flies © NEASY lies the head that wears a crown,” doesn’t apply to the larvae of certain soldier flies; for their crowns are at the ends of their tails. The adults (as one of our pictures shows) are rather’ stout-bodied, un- familiar insects, although about as many species as there are horseflies occur in this country. They frequent the flowers in marshy places and derive their name from their brilliant coloring. The larval period of different species is passed in the earth, in damp moss, decaying wood, ants’ nests, fresh and brackish water. Some are believed to be parasitic in bee hives. To add sstill further diversity to their choice of Popular Science Monthly Crown of breathing hairs be- longing to Chameleon fly larva breeding places one observer states that he found them in a hot spring in Wyo- ming, where the water was estimated to be but twenty or thirty degrees below boiling point—a decidedly close paralle| to the salamander’s mythical capabilities, to the breathing tubes. On leaving the surface, the hairs bend inward, enclosing a glistening bubble which serves to en- close air for breathing, while the little creature wriggles about among the mud and debris at the bottom of the pool in search of food. ‘ The particular one of this family which M takes such decided liberties with the pre. Ww vailing mode of wearing one’s crown, is al the larva of the Chameleon fly. In his a case the crown is no mere decora- 0 tion or emblem of rank, but an 0} essential organ in his breath. a ing mechanism. f ci His crown consists of a about thirty many- — r barbed hairs radiating — 0 from a central disk con- c me: taining two perforations n for the outlets of the p breathing tubes. 7 In the surface attitude k the body hangs downward r suspended by the crown c of hairs, which crown lies t almost flat on the water t forming a very shallow I funnel, allowing free t entrance of the air ( 1 7 i { : During the act of breathing the bub- } ble contracts and a expands.—CLE- | \ MENT B. DAVIs. | PME Se SET a cs nna In the circle, the adult Chameleon fly. Below, two larvae, showing crown closed and open

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Automobile or Railway Car— Which Is It? CALIFOR- NIA in- ventor has de- vised a method which will en- ablean ordinary automobile omnibus to run on railroad rails as well as on city pavements and country roads. It’s an old idea, of course, but with modern “im- Popular Science Monthly used railway line. 887 there was no suitable road but a slightly The bus picks up its passengers on the city streets and & nt b ati agate eee | | Were > a he fo provements.” The Californian bolts a flanged rail- road carwheel and a conventional solid- tired truck wheel together, with the rail wheel on the inside. The circumference of the solid tire wheel is larger than that of the flanged wheel. When run- ning on a pavement of macadam the flanged wheel does not touch the ground at all. It comes into action only when the car is running on rails, as shown in the pic- ture. Small wedges, placed alongside the track, permit the omnibus to run on or off the rails with- out difficulty. The system has been tried out on a sub- urban bus-line in California and has given good satis- faction. It enabled a California motor- bus company to open up new terri- tory between Holt- ville and El] Centro, between which then runs to the railroad line over which it makes its trips. It will probably add a new word to the diction- ary when some philologist shall succeed in con- structinga term that fits this dual-service ear. ‘“ Autorail Car,” for in- stance, or some The wheels of this omnibus will run t i ne smoothly on ordinary railroad rails, ment improvise y city pavements or country roads other suitable combining form indic- ative of the car’s ability to change its nature at the will of its chauffeur or engineer, whichever title may be the proper one. Extending the Use of the Sidecar MOTORCYCLE dealer in River- side, California, finds the sidecar arrange- him to change ordi- nary motorcycles into from the nearest Sidecar arrangement which is decidedly use- ful for the delivery of crated motorcycles delivery trucks very useful ‘in his own business to carry crated motorcycles distributing point, Los Angeles, to Riverside, a_ dis- tance of fifty miles. The trip to Los Angeles and return is made in four hours and requires about fifty cents’ worth of fuel, while the railroad freight on the crated ma- chine would cost $2.50, and delivery could not be ex- pected in less than three or four days.

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New Ideas in Automobiling and Trucking oe as eae se ng 4 Safety First An especially designed auto-guard that equips a car as if it were built-in. “It consists of chan- nel bar, springs and brackets Doing It Gently This flexible coupler for automobile transmission eliminates much of the jar- ring usually re- sulting from the sudden speeding of the engine \ala lala la yh / atc Hauling Freight Cars by Automobile When the freight-car shortage became serious, and proper switch- ing facilities were inadequate, a manufacturing company used an automobile to move cars to the place for unloading Another Ford Accessory An instrument board attachment for a Ford car on which a speedom- eter is placed is shown in illustration at the left Keeping the Wind- shield Clear Below is shown a wind- shield wiper made of a small piece of wire covered with rubber, which is drawn across the glass horizontally Garagemen, Please Notice A stand for holding an automobile engine. It permits the engine being swung in any desired position with great ease Just for the Eye A fancy cut glass side for an automobile top. The glass is set into a frame made of metal 7 To « mani

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New Ideas in Automobiling and Trucking Sper ceccreser sees Undaunted Even by Length This automobile trailer makes it an easy matter to transport telegraph and telephone poles over streets and country roads Saving Your Arm Muscles A swinging arrow arm used on wind-shield to designate the course to be taken is shown at the right. Operatedby driver To from the steering-wheel r 9 « manifold Many-Use Shield The small car wind- shield shown below can be made _ ventilating, slanting or rain vision From carbureter y Good for Starting A master primer. in which an electric coil is used to bring gaso- line to the proper tem- perature for vaporizing Motors for Chickens a Satteecssss Below is shown how Kentucky farmers haul live chickens to the | market on motor trucks Rear axle bearing Motor-Comfort A leather case with a transparent front holds the road guide book and keeps the air from turning leaves For Fords An auxiliary axle attach- ment for.a car so that it can be towed home onits own wheels in case of a breakdown

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Railways That Run Under Water Visit the fishes in their homes as you travel on the Aquarium Circuit difficult, the idea of running rail- way cars upon the bottom of a waterway has its attractions. Air is more easily supplied to the passengers of an under-water car trip lasting, say, one hour than for submarine boats. But the bottom of water is rarely so smooth or firm that rails can be laid on it. In most cases a vast amount of grading and ballasting would have to be done be- fore the ends of the rails could be joined. The under-water car, full of air as it is, would naturally be lighter than water and its buoyancy would cause an upward pull on the rails, which must be shaped ac- cordingly and anchored down securely. Then, in water with ship traffic on the surface, some precautions would have to be taken to prevent ships with deep draft from cutting the submarine car from above, with disastrous results. These and other difficulties have made the counter-attractions of a good ferry seem more powerful for practical trans- portation purposes, and the submarine car so far finds its existence limited to amusement enterprises, where it may combine entertainment with instruction. All that is wanted for this purpose is an airtight car which can be hauled under or partly under the water in an artificial pond by means of a cable. Through the windows the passengers can observe realistic imitations of submarine life and scenery staged in the pond. If the movements of the car are made to suggest the roughness of an ocean bed the illu- sion is improved. One of the first schemes oi this kind was hatched by Alexander Davidson— of Joliet, Ill., far from the ocean. Instead of hauling his car with an end- less cable, as shown in the illustration, Davidson suggests that the car could simply be allowed to run into the water by gravity and could be hauled back by a cable attached to it, as indeed would be necessary whenever, as in the case of a river or a large lake being utilized, a continuous cable is impracticable. nN tunneling is costly and often very 890 Charles B. Stahl of Philadelphia dis. covered that a little more illusion than the Davidson car provides would be desirable, and he fancied that it helps jp this respect to shape the car as a gyb. marine boat, a whale, a sea-serpent or a fish, but his main idea is to supply a track which rises and drops, so that the car will appear to dive one or more times to the bottom of the body of water. With this in view he builds his track as two parallel rails secured to a trestle of varying height, and the track rails are engaged from below as well as from above by little wheels journaled in brackets supporting the car at its sides. The claim set forth in his patent is limited entirely to this feature. More illusion and still more illusion is the cry of the amusement resorts, and so it is found that the submarine ‘‘amuse- ment apparatus” devised by Jacob Gun- zendorfer of San Francisco responds to this demand with some new features “to simulate the actual sensations, scenes and experiences met in traveling in a sub- marine boat.’’ He dispenses with the car effect in favor of the undulating and swaying motions of a boat, the track being made wavy and tipping laterally in places for this purpose. His means for holding on to the track are similar to Stahl’s, and also his traction cable which pulls the car over a continuous circuit of inclosures filled with water or water marvels. But his car is never entirely submerged. The “conning tower,’ where the gripman is located, and some air pipes project above the water-line for the sake of safety and simplicity. As the passengers enter by a hatch which is afterwards closed above them by folding doors, they see nothing but the ceiling when looking up, and their illusion does not suffer. The genius of Gunzendorfer comes out strongest in that he can get along with very little water. As he explains: ‘The trackway first passes into a tank a little distance beyond the elevated loading platform” where the start is made; “the Vl oe ——-

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— —_ —_— —_——_ Underwater Railways Three Different Inventors’ Ideas of Traveling on the Ocean’s Bed The picture at the top shows Stahl’s plan of a sub- marine car shaped like a monstrous fish and running ona “scenic railway” track. It dips and jumps in a Manner suggesting the evolutions of a porpoise 891 Davidson’s idea is a cylindrical car running on a track and hauled by a cable, while Gunzendorfer favors the illusion of a submarine ‘of conventional form which has convenient observation portholes

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892 Popular Science Monthly tank being so constructed as to give the appearance of a lake or river.”’ This last master trick in illusion-making is, how- ever, not explained but hides under the easy phrase: “‘so constructed.’”’ He con- tinues: ‘“‘The track, however, soon emer- ges from the tank and the rest of the course passes through inclosures, all above the water line, the interiors of which are decorated and illuminated to produce various effects. ” The first in- closure may be Sleep in Your Automobile and Han Up the Baby for the Night A RESIDENT of Tropico, California has devised the novel automobile hed equipment shown in the accompanying illustrations. It accommodates two grown-ups and a child, adds not more than twenty pounds to the outfit and takes up no more room than an ordinary “‘camper’s” roll of bedding. The back of the entitled Sub- marine View. “Here will be seen sharks, divers, sunken wrecks, marine growths, etc.’’ The next inclos- ure is advertised as Under the Ice at the North Pole. ‘Here arc- tic views may be shown, such as seals, walrus, Es- kimos.’’ Iron balls suspended within the in- closure and ‘in the path of the vessel (the car) produce by con- tact a grating or grinding sound “in imitation of icebergs striking the vessel.’”’ Such is the inventor’s idea of an iceberg! The port- holes through which the passengers view the wonders ‘‘are provided with convex lenses which produce the desired illusion of distance, swirling motion, etc.’”’ In other words, they blur the vision to make the passenger’s imagination work more willingly. ‘‘The illumination of the dif- ferent inclosures is controlled by the passage of the submarine,” by electric contacts on its dummy periscope. Altogether, there should be _ shocks enough in a trip like this to provide the least fertile imagination with thrills suf- ficient to last the average individual quite a while—and, incidentally, to make him profoundly grateful that the trouble is imaginary. Without that comforting knowledge enjoyment would be dubious. This shows how you can arrange beds for two adults and one baby in your automobile front seat is cut down so that it can be dropped backward, to fill the space be- tween the front and therear seats, This makes a bed of the interior of the car, large enough to ac- commodate two grown persons. The bed for the youngster con- sists of a han- mock, which is swung above the bed. This ham- mock may be made of duck, about thirty inch- es wide by fifty- two inches long. The Secret of the Wily Snake’s Sinuous Glide ID you ever watch a snake gliding over the ground in graceful curves and did you ever stop to think of the mechanical principles involved in its motion? The snake moves along the ground in undulating curves produced by the contraction of the longitudinal sys- tem of muscles in alternate sections of its body. That alone would not produce a forward motion, however, were it not for the friction of the scales on the underside of the snake’s body against the rough- nesses of the ground. By bracing the rear part of the body, the forward part is enabled to glide forward and by re versing the process the rear part 1s dragged forward to a new position.

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No Double Exposures with This Device “T)LESSED if I can re- member,” exclaimed ar, “whether or not I’ve eo the film after tak- ing that waterfall a little whileago! IthinkI’ll give it another turn for good luck!’ When the film roll was developed Oscar found a blank next to the negative of the waterfall and a double exposure in another part of the film. To put an end to such uncertainty, Oscar—his full name is Oscar Howard Wil- ber, Jr.—has patented a very simple device which may be attached to any film camera at small cost. A flexible rod, sliding in a sheath, is so arranged, that after the trig- Popular Science Monthly Pe 3 © Western Newspaper Union These choir boys take knitting seriously and do good work ger of the shutter of the lens has been pressed down to make an exposure, the O* course Sister Susie’s been sewing front end of the rod is pressed forward by a spring so as to bar the trigger from returning to its former position. To remove the. obstacle and make got a good start. another exposure possi- ble, the receiving roll has to be given another turn, which naturally brings an unexposed fim before the lens. By turning the roll the flm is drawn over another roll, provided with a disk at one end. That disk has a tooth which engages, at each revolution, the hook at the other end of the flexible rod, pulling it back and thereby re- leasing the trigger of the shutter for another exposure. This clever device will Spare many an amateur photographer the dis- appointment of losing, by double exposure, a picture valued for its happy associations with a pleasant vacation. Release hook Release cog With a film camera equipped like this one even the most for- getful of amateur photographers cannot make a double exposure Knitting Is Not by Any Means Confined to the Ladies shirts for soldiers for some time now, and has also been knitting sweaters, socks, scarfs, etc.; consequently she has Still, she must look to her laurels, for there is a valiant host of rivals springing up— the boys are taking a hand. In our illustra+ tion is seen a group of Cathedral choir-boys in New York, who have (ostensibly) foresworn horseplay and mischief in the intervals of wait- ing, and are seriously knitting comforts for the soldiers and sailor- boys. They have been properly and thorough- ly instructed and are turning out just as good stuff as their sis- ters do. The boys dis- play a remarkable seri- ousness of purpose in their new task and no longer consider knitting as mere girls’ work unworthy of the atten- tion of a manly boy.

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894 Popular Science Monthly Notch the Curb to Keep Out Automobiles ALIFORNIA automobilists frequently mistook a motorcycle for an automobile garage and drove in with their machines. When the drivers learned their mistake they turned around and left, frequently knocking over and damaging some of the motorcycles in the garage. The owners of the garage used a very simple and effec- tive method to keep auto- mobiles out of their place without interfering with the passing in and out of the motorcycles. They had the inclined driveway to their garage supplanted by a curb, too high to be scaled by automobiles. For the use of the motorcycles a notch of liberal width was cut in the curb, offering a sufficiently wide and slant- ing runway to and from the garage. Now if a belated automobilist mistakes his goal he will be _ rudely awakened to the fact by a bump which will jar him in direct proportion to the force. with which he hits that curb. Putting Overalls on Automobiles for Protection WING to war conditions automobile manufacturers meet with increasing difficulty in securing box cars for shipping their automobiles to their dealers and agents. Many concerns are compelled to deliver nearly ‘all their cars by running them overland to their destination. The cost of refinishing such cars after they This shows an automobile dressed in its overalls for protection against scratches have passed through rain or snow storms has become a serious question. It costs > This notch in the curb permits motorcycles to pass, but bars automo- biles very effectively about one hundred dollars to drive one car overland from Detroit to Baltimore as compared with thirty-four dollars by railroad. Any additional charge for fe. finishing the body simply adds to the cog of the car to the final purchaser. To eliminate the charge for repolishing bodies scratched by mud, sleet, rain or snow, a Baltimore automobile dealer hag invented the car overalls shown in the accompanying illustrations. Each set costs about thirty-five dollars and weighs thirty-nine pounds, It can be folded up into a parcel small enough to be put in a suitcase, to be car- ried back to the factory by the driver when he returns for his next car. The device consists of a padded stick across the front of the radia- tor, to which are attached strips of webbing which are stretched taut on each side of the car. They serve to button down pieces of rub- berized top material that completely inclose the body, yet do not touch it. Strips of wood along each running board serve to hold the pieces out at the bottom and straps at- tached to the top serve the same pur- pose higher up. over the radiator and front springs. The right-hand picture shows how the padded framework and webbing are adjusted to the car, while that to the left gives an idea of the absolute pro- tection against dirt and scratches which is afforded to the car body by its overalls. A separate covering fits neon Showing the framework of sticks and webbing which holds the overalls in place

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ae Sa er ee ee Sy wes ww @ FS oe Se ie | —— Here Is That One-Hand Cigarette Case You Want EMEMBER that time when you were in the car, dying for a smoke, and the traffic so Popular Science Monthly 895 Use Folding Bunks to Economize Space on Trip ‘‘Over There’’ WING to the lack of ships the trans- ports taking the American soldiers to France have to thick that you couldn’t take your hands off the wheel for an instant? Of course you could carry your cigar- om in the packet in your vest pock- et, but they are crushed and they dry out. Here isa cigarette case de- be loaded to their full capacity. In day time it is a comparatively easy matter so to dis- tribute the men that there is no overcrowding in any part of the ship. But at night the men have to sleep, and to be signed to help you in just such emer- gencies. - You load the case when you start out by taking off the cover. After this you merely press down the cover with the thumb and push it back again. This causes a cigarette to be protruded about an inch so that it can -be drawn out with the lips. A spring then pushes another cigar- ette into place ready for the operation to be repeated. The magazine of this neat little device holds ten cigarettes of aver- age size. The case may be made plain or ornamental as in- dividual fancy may dictate. lie down. vention. rr er er On the left the cots are folded. On the righ they are shown as they appear when used as beds It’s simple to get the cigarettes in and simpler to get them out—with one hand able to do that they must have sufficient room to The difficulty of providing sleeping room for the men on over- crowded transports has stimulated in- One of the simplest and best expedients adopted is shown in the ac- ail companying illustra- tion. Hinged to upright posts are three tiers of folding frames, the free ends of which, when in a horizontal position, are supported by chains. Each tier has two of these frames, which serve as bunks. The elastic wire net- ting supported by the frames forms the mat- tresses. When the bunks are not in use they are folded up against the posts, an arrangement by which space is greatly econo- mized. Another ad- vantage of these bunks is that they are easily kept clean and sani- tary; and this is, of course, of the utmost importance where a large number of men are thrown’ together for several days in cramped quarters.

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ane See SAS Aaa Teles Tania Se AR SO eS Popular Science Monthly poured into a smaller bottle A definite amount of water goes into the third glagg container, above which rigeg a marked gage. The three bottles are tightly corked and connected in series by rubber tubes. The action of the acid upon the lime provided by nature in the soil creates a gas which passes into the tester and forces some of the water to rise in the gage: If no re. action results, it shows that no lime is present in the gojl, If the water rises to the mark for three tons per acre or This apparatus will inform the farmer how much lime, if any, his fields require to make them productive Every Farmer May Be His Own Soil Chemist VERY available acre must be made to yield to its full capacity if the United States and our allies are to win the war. Many soils fall short of their full productive capacity because they are sour or acid. This condition can be remedied by applying a sufficient amount of lime. above it, the soil contains all the lime it needs. It should contain at least three tons in each acre and if the gage shows only two tons it means that the field requires an additional ton of lime for each acre. The simplicity of the device makes it possible for the intelligent farmer to con- duct his own experiments and apply the remedy called for, thus making it possible to keep the soil always at its highest de- gree of productiveness. A Camouflaged To overcome the difficulty of determin- ing exactly the amount of lime nec- essary to neutralize the acidity of the soil a simple apparatus has been designed and placed on the market.’ A test re- quires but a few min- utes. Representative samples of earth from various sections of the field are mixed to make the average soil of a field. The earth is dried, sifted and weighed in the seales which form a part of the tester, then placed in a glass bottle. A carefully Well-Curb OND memories of his childhood days on the old farm in Vermont induced R. E. Sperry, a resi- dent of Inglewood, California, to place a replica of his fa- ther’s well-curb in the garden of his Cali- fornia home. The curb, roof supports, roof, and even the “old oaken bucket,” are made of concrete. The well is a well in name only, ob- taining its water sup- ply from the city mains, but it serves the sentimental and measured amount of muriatie acid is An imitation, in concrete, of an old Vermont well with picturesque purpose “oaken” bucket desired. ee i Oe ee ek tl ee ak, oe ee eee

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Holding the Screw to the Screw- Driver with a Vise-Grip ARPENTERS, wood workers, machinists and other workers who use screw-drivers fre- quently have to do their work under con- ditions which make it impossible to use both hands at the same time in starting ascrew. For many years the need was felt for some device that would hold the screw firmly against the edge of the screw- driver, that could be quickly put on and taken off and that would fit screw- drivers and screws of any size. The screw-holder invented by David H. Royer, of Hart- ville, O., fulfills these requirements and is comparatively simple in construction. The mere turning of a lever closes the jaws and clamps of the device, so as to hold the screw and the screw-driver securely. By merely throwing back the lever, which works on the principle of an eccentric, the grip of the device is released so that it can beremoved. To adapt the device for use with screws of different sizes, keys or wedges are used, which are inserted between the screw- holding part and the yoke, opposite the eccentric-lever clamp. Where scréws are to be inserted at heights beyond convenient reach, or where lack of space interferes with the workman, this device should * prove especially use- ful. Popular Science Monthly

a

The man in the picture does not have to hold the screw. The device below does it, leaving his hands free

tomato or fruit.

ec

—7\ , » To ground™

) HighWoltage | current from f transformer)

The high voltage sparks puncture the tomato’s skin and loosen it

897 Electric Sparks Peel the Tomatoes. Here’s How It’s Done ILLIAM H. CHAPMAN, of Portland, Me., dis- covered that electric sparks, if allowed to strike the skin of a tomato, will puncture it and, by expanding the air underneath the skin, loosen it from the pulp. He thinks that he has solved the tomato- peeling problem for canners. The tomato or fruit to be treated is im- paled upon a fork ro- tated around its long axis by a mechan- ically or electrically driven pulley. The fork is connected with an insulated wire which leads to the ground. A sliding base, operated by a handle, has, attached to the vertical post at its front end, a curved part lined on the inside of the curve with comb teeth of metal, through which sparks of a high voltage alternating current are allowed to pass to the impaled It is claimed that the device-is very <ifective and does its work quickly ana thoroughly. This invention Pe ig ™™ CAD will undoubtedly be of particular value to canning factories, where large quanti- ties of tomatoes have to be peeled. For factory use, a modi- fied form of the de- viee is available. The accompanying illustration conveys an idea of the work- ings of this device. . The power may be obtained from an electric or other form of motor.

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F his first machine Sir Hiram Maxim said, over twenty years ago, that, completely stalled in the air, it would ‘‘pancake”’ down with the velocity of a fall of four feet. But these old machines were loaded barely more than one pound to the square foot, and their center of grav- ity was far below their carrying sur- face. The arrange- ment, as we know now, prevented easy flight, but it made them good para- chutes. The more perfect and efficient the modern airplane became, the more it lost its former like- ness to a parachute. The wings of mod- ern airplanes bear a load of five to seven pounds to the square foot and the center of gravity has been raised. Stalling and pancaking are nowadays considered worse than upsetting and “looping the loop’’; yet pancaking, that is, descending like a parachute, is obviously the safest way to land on badly bro!en, mountain- ous ground. Very interesting is a revival of Maxim’s parachute idea in modified form, by Gerrit Van Daam, because it aims at making safe not only stalling but also landing on the worst ground. . It is not feasible with heavily loaded biplanes, since in their case one wing surface blan- kets the other; but with lightly loaded monoplanes of the Blériot type the plan may work out satisfactorily. What such monoplanes lack in surface for a para- chute-like descent, the inventor makes up, more or less, by turning the wings into true, highly-arched parachutes of increased air-resistance. A parachute is tightly folded over the whole upper surface of each wing, being Parachute Safety Device for Airplanes A new attempt to revive the late Sir ‘Hiram Maxim’s idea of twenty years ago By releasing the parachute and opening long slots in the wings through which the air rushes under the parachute, the descent of the airplane is made safe 898 held in place by a netting. When needed, this netting is instantly loosened and at the same time a long slot opens along the center line of each wing, ad. mitting the air from below into the | spacious pocket formed by the distending | parachute, now held only by the margin | of the wing. Smoothness of the wing tops in flight js absolutely essential: so the folded para. chute and the net. ting will have to be covered, while not in use, by a smooth light shell firmly se cured to resist the air suction, yet easily removed when nec- essary. Of greater importance is a de- vice that will keep the pancaking airplane on an even keel dur- ing descent. That is not so easy witha machine of the Blé- riot type. In that machine, the tail makes an excess of surface toward the rear, while the advanced center of gravity, balancing the equally advanced center of lift, gives an excess of weight in front. The only remedy would seem to be control independent of the machine’s headway, or adjustable rudders with a circular motion of their own, which remain efficient in a stalled machine. Numerous attempts have been made in the past by inventors in many countries to utilize the principle of the parachute in safety devices, but the success has not been encouraging. Parachutes have been found useful and fairly reliable for drop- ping from observation balloons, but have failed to give satisfaction as a safe means of escape in practically all other cases. They have not been used extensively for military purposes; but perhaps this new a ail device may solve a_ hitherto baffling problem and thus add to the balance of safety in the aviator’s favor.

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SS we F- ee er ae Us rT S&S = ce bed oo = Trench-Dwellers Cherish the Barber’s Ministrations RY to imagine yourself in the place of a soldier who has spent two or three weeks or months in the trenches, cut off from every comfort and at all times exposed to the risk of being killed or maimed by bullet, shell or shrapnel. -The excitement of the first few days gradually wears Popular Science Monthly af wf x00 Kawaan ¢¥Ew a warn 4 ov Kansas Crry ro sue aDye te May - off; but the discomforts of trench-life remain and become more irksome from day to day. Little rest, little food, no chance to bathe or even wash, no opportunity to get a shave or a haircut. Such is trench-life. Can you realize what it means to a soldier who has gone through that life for many days and weeks, when at last he is relieved and sent to the rear of the fighting line? A soldier’s first thouhgt is a bath, then a shave and a haircut, clean clothes and a hot and plentiful meal. Fortunate the man who has among his treasured possessions one of those comfort kits which, in a small compass and in practical arrangement, contain all the things necessary for a man’s toilet: brush, comb, scissors, razor, soap, taleum pow- der, etc. The picture shows one of these kits which is particularly practical because it can be carried by a strap over the shoulder. It is thus possible to get an open-air haircut or Check-raisers take notice. The amount to be paid is cut out of a double row of figures Making Things Harder for the Forger of Checks N unusually clever device for pro- tecting checks from being raised by forgery has been invented by C. W. Elrod, of Lincoln, Neb. The accompany- ing illustration clearly demonstrates the idea and its application. At the top of the check is a double row of figures indexing dollars, another double row indexing cents. The figures representing the amount of the check are cut out of that double row of index figures in such a manner that they appear on the little triangular tabs which in cutting were left attached to the check. The control-strip, detached from the check and forming part of the stub of the check, shows, cut out of the first row of figures, the figures repre- senting the amount shave with all the necessary adjuncts, though some of the comforts of the city barber shop may be lacking. But the soldier will scarcely mind this. of the check; which may be identified by the corresponding figures in the second row. The inventor proposes to have the paper of the checks watermarked with the words: “Only good for amount shown on margin,” as an additional pro- tection against such forgery. Those who have been victimized by bank swindlers will be glad of this in- Trench barbering is frequently an outdoor operation. Our pictures show procedure and comfort-kit con- taining all the implements of the barber’s trade genious means of protecting them- selves hereafter.

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Jeff Tesreau, the star pitcher of the Giants, about to baf- fle the bat- ter with his great spitball © Underwood and Underwood lh ke definite explanation of the vaga- ries of the spitball or the “shine” ball has ever, so far as I am aware, been given. tions, but no specific explanation, and so I am now essaying the task in the hope that it may prove interesting, and possibly serviceable, to players of baseball. Definite and consistent curves in base- ball, or swerves, as they are called in cricket, can be produced only by spin imparted to the ball by all the fingers and thumb or some of them. Comparatively few people know that the “‘top” of a wheel moves more quickly through the atmosphere than the — tom”; yet this is undoubt- edly so. The reason is that at the “top” of the wheel the motions of revolution and progression “‘conspire”’ or coincide. .To put it, perhaps, a little more simply we may say that the wheel is going forward and is rolling for- wardly, therefore at the top we have the sum of these two motions. It is otherwise at the bottom of the Here, as this portion of the wheel is revolving backwardly, the rotary mo- tion conflicts with the progressive motion, 900 wheel. I have seen many generaliza- The Spitball Spin A to B. Flight Dto E. Therefore spin and progression conspire at portion shaded dark, C. At portion F, the spin is against the progression. Cofisequently, the ball is forced towards F’, as there is less friction there than at C Spitball Myths Why pitched baseballs curve and why the spitballs are scientifically foolish By P. A. Vaile [Author of ‘“‘Swerve, or the Flight of the Ball,’”’ ‘‘ Modern Golf,’”’ ‘‘ Modern Tennis ’’] and instead of the sum of two motions, we get the difference. Of course all por- tions of the wheel viewed as a whole are progressing towards its destination at the same rate. It is merely that certain constantly-changing portions are moving . | through the atmosphere at different speeds. That, shortly, is the whole secret of curve or swerve, for the side of the ball whereon the motions conspire sets up wnore friction with the air than that on which they conflict. A projectile always seeks the line of least resistance, there- fore the ball is forced over toward the side where the spin is backward. I may here repeat that there is, so far as I am aware, absolutely no other means whereby definite and consistent curves with a ball can be obtained. If. there be, and anyone can tell us of them, the scien- tific world will be much interesicd. This brings us to a consideration of the spitball and the “‘shine” ball. Any curve that these balls have is not due to the action of the air on the wet or shiny patch on the ball. It is due to the amount of spin that is imparted to them by the pitcher on ac- count of those patches. What finally decides the nature of the spin on any ball must necessarily be the last point of con- tact between the ball and the player. If a ball is held, say, mainly by. two fingers and a thumb, and pitched from that hold, the flesh grip of the three engag- ing members may be ap- proximately the same, except for the force of gravity’s bearing the ball down on the lowest of the three, and the push of any downwatd action in the throw. Now, suppose that the portion of the ball remote, or farthest away from the lowest engaging member, naturallv, in oe

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a a. Gy “So 9 _— = ee ee ene Aa ences tenn ptena il —— most cases, the thumb, is touched or held on a spot that 1s covered. with moisture or has been made smooth and shiny with some substance. It stands to reason that the ball will slide away here with less friction than where it is held with a natural flesh- rip. It follows there- fore that this artifi- cial release must have considerable influence in determining the amount of spin im- The “shine” ball and the spitball ; ) é Shine At left: ‘‘Shine” ball leaving pitcher’s Popular Science Monthly 901 show on the other side, when it would produce a return swerve! , Then baseballers would in that case have a new ball, the zig-zag! The effect, if any, on a similarly-pro- pelled “ shine” ball would probably be opposed to that of the spitball. The erratic flight of these balls, and, comparatively speak- ing, the lack of con- trol over them that parted to the ball, and —— Fg ‘+ : “Shine” ball going — the pitcher has, lend . plate. e least resistant portion, the ° it would seem a rea- shiny patch, has pore to the front color to the idea that sonable deduction that the amount of spin and consequently of curve must vary considerably to cor- respond with the de- gree of slipperiness of the patch on the ball and whether it was on. top of the ball or on the bottom. If anyone thinks that the curve or swerve in these balls is obtained from the effect of the shine or the spit, apart from the action of the spin, he may speedily disabuse his mind of the idea by put- ting a number of “shine” or spitballs in a driving ma- chine, such as those used by golf-ball makers, and propelling them violently. If, as is quite conceivable, the patches had any effect, it would not be consistent and persistent, for, if the wet retarded one side of the ball enough . to be appreciable, ont =the wet patch ' Serv. would speedily go aes oF ie behind the ball oF lh age and stay there, or after delivering a powerful ‘“‘spitter” swing across and *) Moisture At left: Spitball leaving pitcher’s hands. At right: Spitball going over plate. Moist- ure having gripped the atmosphere, that portion goes behind the ball during its flight, which it does not‘dc in practical baseball their production is, as TIT have indicated, largely adventitious. Many prominent players think that any attempt artificially to alter the natural flesh- grip should be stopped by law. This must al- ways be difficult; but if pitchers would only understand that, to a very great extent, the spitball and the “shine” ball are myths, they woulddo much better with a natural delivery, backed by a little more practical knowledge as to what it really is that they are trying to do; and batters would lose a bogey. © Nerve Shock Due to Detonations Less Wearing Than War Strain HE term shell shock has misled many persons to believe that it is due to the profound impression or shock pro- duced on the nervous system by the detonations of high explosives. No doubt, there are cases of actual brain or nerve injury due to concussion of the air ac- companying shell explosions, but these mechanical causes are a great deal less frequently responsible for war neuroses than the mental effects of general war strain. It is remarkable that these war neuroses, common as they are among privates and officers alike, are seldom found in men who have been actually wounded. Perhaps this seeming anomaly is due to the actual wound shock offset- ting the mental impression affecting the. controlling nerve-center in such cases. See

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Popular Science Monthly A passenger ferryboat rammed this mammoth floating drydock in a dense fog. The damaged sec. tion promptly separated from the others, turned sidewise and floated inside its former companions Nothing Troubles This Drydock. It Can Repair Even Itself HE big floating drydock in the harbor of Tacoma, Washington, was rammed in a dense fog by a passenger ferryboat, and one of its four sections driven in. The ferryboat was of the old-fask ‘ned river type with a draft of only three feet. In the winds and currents of Tacoma’s open harbor it was notoriously unmanage- able. But the drydock was a match for the ferryboat. The section which the ferry- bost had damaged was promptly . sepa- rated from the others, turned sidcwise, and floated inside its former companions. Men thereupon went to work with a will and elevated the damaged brother above the water’s surface so that repairs could be made. And by this time all four sec- tions are back in the water again, joined together, and doing each day their daily work as if nothing at all had happened. Incidentally it may be worth Dry ioe ‘ Does a Locomotive Wheel Travel Slower or Faster than the Train? T is an interesting point to consider that on a locomotive wheel, the cir. cumference is continually traveling at different speeds. First a point on the circumference of the wheel will go faster than the rest of the locomotive; then that same point will go slower; at stil] other times, the point will travel at a speed equal to that of the locomotive cabin. This paradox is explained by con- sidering first the point on the circun- ference farthest to the rear of the wheel’s center. When the center of the wheel moves forward with the same speed as the rest of the locomotive, that point will move around and in a short time it will get ahead of the center. Obviously, to do this, this noint has to travel faster than the locomotive. . A As the train moves on from this position, a however, the average while to note that doztoring up the damaged section was the drydock’s Cm speed of that same | point will become less ‘ST A | first job, and it accord- ingly started a life of repairing by first re- pairing itself. In the _ illustration above, the entire dry- dock is shown at the left, while at the right the damaged section is shown inside the two submerged sections of its former self, undergoing repairs. The diagram below shows how collision between drydock and ferryboat occurred. Ferry ysl OF How ferryboat hit the” dock that repaired itself than that of the loco- motive. This is evi- dent, since the point will soon change from a position directly in © front of the wheel's center to another point directly in the rear. This apparent para- dox is not related to the old saw con- cerning the relative speeds of a kangaroo’s hind legs and front legs when jumping Australian sand hills. a) * ‘ no 3 site a] 3 i) e -¥ @aeeee2eeee Wind and current forced ~" against dry dock / -"Soheekee | oats cot wa

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oe FS & “ DW er 6 =, C—O oe CPO ee CO ' # ' a= wae Se |! evr Bae S&S or 8 What Makes the Rum- ble of Thunder? HY does’ thunder rumble? The path of a lightning flash through the air may be several miles in length. All along this path the sudden expansion of the heated air—a true explosion—sets up an at- mospheric wave, which spreads in all directions, and eventually registers upon our ears as thunder. Since the lightning dis- charge is almost instanta- neous, the sound wave is produced at very nearly the same time Popular Science Monthly ee eget hee oe ee Mn et re Yee © Kadel & Herbert This huge bat-like kite is the plaything of a Japanese prince. His place in the world requires distinctive size even in his toys along the whole path. But the sound wave travels slowly through speed is approximately 1,090 feet per second. Thus the sound of the lightning’s path that is nearest to us reaches us first, and that from other parts of the path afterward, according to Intermittent crashes and booming effects are due chiefly to irregu- larities in the shape of the path. tip. their distance. Making Window- Cleaning Safe OR the benefit of window cleaners and painters, Paul Wolff, a Hungarian in Pittsburgh, Pa., has invented a win- dow chair or scaffold, which rests upon the window sill, extending outward and providing the workman with a se- cure support. The de- vice is so arranged that it'can quickly be clamped to the window frame and just as readily removed. The win- dow frame is firmly held between a rub- ber-covered hook or brace and the mov- able clamp, which is operated by a screw, like the movable jaw of a vise. the air. Its from the part Giant Kite for the Crown Prince of Sunny Japan HILE the Crown Prince of Japan was on his winter vacation at the palace of Numazu he had the huge kite, which is the subject of our illustration, made for his amusement. is in the form of a bird and it measures twenty-four feet from wing-tip to wing- It is capable of attaining great This monster heights and its pull is so powerful that it can lift a man off his feet; consequently, special winding Chair clamped to window frame with the movable jaw ofa vise machinery is needed to con- trol it. What American boy would like to swap places with the heir to the Cherry- blossom Empire’s throne? Step lively, boys—the line forms on the right! Half Million Words in English Use HE English vocabu- lary has grown to great size, according to Professor Clark S. Northup, of Cornell University. “The number of words found in old English litera- ture does not exceed thirty thousand; re- cent dictionaries have listed more than four hundred thousand.”

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cE T autumn, when the railroad con- gestion became acute, the State of Connecticut, which is the heart of Solving the Railroad Problem Connecticut does it by making the return trip profitable for motor trucks nies and their routes to shippers and keeps a record of all applications. This enables the small arms and ammunition industry of the United States, found itself in a desperate situation. - Ammunition partly finished in one plant must be hauled to other plants for differ- ent machining opera- tions before it is com- pleted. As there were no freight cars at all, or too few, the war ma- terial could not be moved by the rail- roads. Many manu- facturers had to use motor trucks for that purpose, and, in some CITY CARDS WITH SHIPPERS A file like this is kept in every one of the Return Loads bureaus in fourteen cities of Connecticut the bureau to post the truckmen on the prospects of obtaining a return load to their home city after they have delivered thcir outgoing load. The telephones of the bureaus are listed under the heading “Re. turn Loads’ to faeilj- tate telephoning. The ROUTE NUMBERS ©0,@-----@ WITH CARDS BEHIND EACH NUMBERED TAB GIVING NAMES OF AVAILABLE TRUCK QWNERS = = = numbered, and the trucks running on each route are given cor- responding index num- bers in the file. Ther: are already more than seven hundred motor trucks listed under this plan and each bureau 5“. > cases, even to get raw ma- & has a complete file of all terials for their plants and to deliver finished goods to New York for shipment abroad. The first problem was to keep the roads open. This a 9 YUDKINe Sox __ROUTE @}|| available vehicles and a map 202, Conspuse Gut. uch,|| Of the routes covered. ste ttm Stew |s' Since it costs almost as mace: much to run a truck empty as as it does loaded, it will Yaw Howat Gridgpet! | easily be seen how advan- routes covered are was accomplished by taking the work of removing the snow out of the hands of One of the City cards bearing the name of a trucking concern listed in the files of the bureau tageous it is to both shipper and truckman to be sure of a return load. the townships and turning it over to the State. The second problem was to make the haul- age as economical as possible by providing return loads for the trucks. - To make sure of return loads, the State, under the direction of W. S. Conning,-chairman of the Motor Truck Transporta- tion Committee of the State Council of Defense, formed Return Loads Bureaus in four- teen of the important cities of the State. Each bureau keeps a file of all the trucks available for overland haulage work. The bureau supplies information re- garding trucking compa- is j i $ | ae ae 7. a € y PARTFOR! 5 u ~ Qo - ae © ie: ‘waTereoury Cif \ 2 r—¥ 1 Ge Bee I ~ tw MAVEN sound? o $5 fw he Owe BV Be s n O 4 SALE do MLES Map of the State of Connecticut showing the various routes for overlana trucking established so far in important cite

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—- es a Pane 1 padaenaaheiah lineage PED Beware of the Perils of the High Heel Listen to the warnings of Pro- fessor Quénu and Doctor Ménard T one of the recent sessions of the Academy of Medicine of Paris an interesting communication upon the subject of high heels was submitted by Prof. Quénu and Dr. Ménard, closing with the ominous warning: ‘Ladies, if you value your health, give up the high heels of your shoes!”’ Several years ago Dr. Dagron, a noted French physician, called atten- tion to the injurious effects of wearing high heels, but his warning made but dittle impression. Since then, however, the subject has been more thoroughly studied with the aid of X-Rays and moving pictures by Quénu and Ménard. These two investigators have found that an unnatural strain is placed upon the muscles and tendons of the foot, as well as upon leg muscles forced to accommodate themselves to the task of maintaining the equilibrium of a . body unnaturally raised by the heels. The strain caused by this effort is so great that fatigue is experienced even after a short walk. The effects of wearing high heels are even farther reaching than was suspected heretofore. The change of the position of the foot disturbs the equilibrium of the whole body. As there is a tendency to bend the knees the upper part of the body, the head and chest, is thrown back, while the abdomen is forced forward beyond its normal position. The physicians state that the disturbances caused by the wearing of high heels, the disarrange- ment of the articulated bones of the foot and the throwing out of their nor- ’ mal position of the different parts of the body are serious enough, but that in walking these effects are so aggra- vated, that they produce the most serious internal disorders. The skeleton on the left shows the graceful poise of the normally supported body The skeleton on the right shows how high heels change normal position of the bones 905

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906 Popular Science Monthly j The “Little Church of the Flowers’”’ you left in your destructive wake? -]f and How It Got Its Name this harrowing experience has ever been | yours you are going to give the inventor i} HE latest thing in churches is to be of a new little wardrobe your heartiegt found in a southern California and most unqualified support. Here it jg: town, in the _—— To accom. way of grow- modate the hat ing plants. there is a sli- Two rows of ding rack up- 1p shaibaepntnne less actit a tA seats and a der the seat center aisle which extends comprise the and folds up | middle of the i. building. On 1 4 each side be- yond these seats are beau- tiful arches, from which large fern bas- kets are sus- pended, and beyond these work, to whi / arches, on both Growing plants and flowers give a peculiar charm : which, | pena A sg : a in turn, is at- | ide at the ‘Oo s little church in a southern California town deseal a long building, is a sloping roof of sky lights. cylindrical receptacle for the cane or A cement walk extends between two umbrella. The whole forms a remarkably rows of ferns, shrubs and flowering plants. compact and complete wardrobe that will In the columns are little pockets where accommodate all one’s street clothes with- _choice begonias bloom. A similar church out the bother and inconvenience of the will be built in Los Angeles. checkroom, with its crush and scramble and long line of waiting patrons, and, This Device Will Take Care of Your 48t but not least, there is no tip. | Owners of theaters might find it good Street Clothes at the Theater policy to introduce this device in their ID you ever, dear reader, have the houses, partly as an advertising novelty I misfortune to reserve seats at the and partly as something contributing to theater and not arrive there until after the comfort of their pa- the performance had started? Do you trons. It will,nodoubt, — coat Hancer remember taking your coat offin thelobby pay in added good-will. PROTECTING and carrying it on your arm down to your seat? And then ag Sa on the lazy | tongs prin | ciple. Forthe — coat there is a han ger at. ( tached to the | back of the seat and the coat is protected by a light frame- es ee ee ee ae ee ee a the wild scramble past all the other people in the row, with the result- ing frenzied grab- bing of hats and coats and wraps so that you would not accumulate them in your career as a snowball grows as it Imagine yourself in that rolls down a hill? man’s place and you will Do you remember sympathize with him ood re. “ : Like a modern trunk this COLLAPSIBLE STATIONARY 1 en rs asty device will hold your hat, HAT AND WRAP REAR WALL expressions that overcoat and umbrella RECEPTACLE BROKEN AWAY SPRINGS

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a aad | | Popular Science Monthly A New Use for the Little Tractor: . Spotting Freight Cars for Large Plants SMALL industrial ‘‘creeper”’ tractor can “‘spot’’ a carload of coal having a total weight of 45,000 pounds. The illustration proves it. One of these tractors has taken the place of a switch- engine or a gang of workmen with pinch bars for spotting or switch- ing cars at a large industrial plant in Ohio. As the engine is rail- road property, it is available only © Underwood and Underwood owas be 4 © omparatively short time The protective power of the armorplate of the turret each day, while the tractor, is greatly enhanced by a layer of sandbags as shown which is always on the premises, can be Sandbags Used as Protective Cover- utilized at all times. The tractor does not travel on wheels, ing Even on War Ships but lays its own track, and consequently HE use of sandbags or wicker baskets can pass over obstacles and move material filled with sand as a protection from one department to another without against hostile projectiles in warfare is marring the surface over which it travels. by no means new, but the present war has The over-all width of the tractor is fifty probably seen the most extensive use inches and it is but two inches more in ever known of this means of defence. height, so that it can pass through or- Against the enormous force of the modern dinary sized factory doors easily. The explosives neither steel nor concrete offers tractor is used for bringing material from adequate protection. It was found that the factory to the shipping room or to’ earth or sand, either in a loose state or cars that are to be loaded and for the in bags, formed a more efficient protection unloading of incoming shipments, and it against shells, shrapnel or the projectiles also transports material between the of small arms or machine guns than barri- various buildings of the plant. cades of other material. This little caterpillar tractor can pull without trouble a loaded car weighing 45,000 pounds, and do it easily The accompanying picture taken on board of a British monitor preparing to go into action shows that sandbags as a means of protection are by no means confined to the warfare in the trenches. A covering of sandbags is placed on the roof of the turret to give additional protection to the big guns and the gun crew, should they come with- in range of a hostile battle- ship, or be attacked by a hos- tile airplane. Without these sandbags the roof of the tur- ret would offer little protec- tion against missiles dropping upon them almost vertically. This applies to projectiles fired from guns with a high angle of elevation and to bombs dropped from aircraft.

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a ee ee ee a 908 Popular Science Monthly Flexible Coupling Takes Side Strain A First Aid to the Singing-Teacher. Off Shafting NLESS there is perfect alinement of the propeller shaft with the engine or reverse-gear shaft there is sure to be trouble in any enginé-propelled marine craft. Binding bearings, with resulting friction, hot journals and loss of power, It Analyzes the Voice Phase tone of the human voice jg composed of fundamentals and over. tones, according to the musical authori- ties. It is the presence or absence of the overtones which decides whether a tone is musical or otherwise. Hence overtones or excessive vibration This bolt takes and consequent ‘wear hetent. are the natural results of the side strain caused by the imper- fect alinement. Asa truly perfect aline- ment is possible only in theory, some pro-- vision must be made to compensate for de- The fects in the alinement which may develop from various causes at any time. It was found that a flexible coupling for connect- ing the propeller shaft with the engine constituted the best remedy. One of these flexible couplings, which has been successfully tried for marine engines of various types, is here shown in cross section. The coupling consists of two cast-iron or steel flanges con- nected by flexible lami- nated steel pins instead of rigid bolts. The con- struction of the coupling is made plain by the diagram. The center bolt takes the push or pull, as the case may be, from one shaft to the other. The flexible laminated steel pins, which connect the two flanges, allow sufficient play to give the coup- ling universal action within its intended limits. The pins take no push or pull, their business is to drive. It is expected that this arrangement will elim- inate much trouble hitherto encountered. reverse pull \ The center bolt gives the required rigidity to the coupling, the lami- nated steel pins of the flange give it the necessary flexibility ; 5 minima T TTY The student sings oS el into the tubes to t est quality of voice constitute the essen. tials of the singing voice. Professor Howard H. Hanson, of San José, Calif., has per- fected a device which determines what over- tones of a particular voice need cultivating or subduing for the sake of bringing the voice up to its maxi- mum beauty. The de- vice is constructed principally of tin and resembles a huge stove-pipe joint from which tubes of various lengths and sizes protrude hori- zontally. There are sixteen of the tubes, and each is tuned to a different overtone of middle “C.”” When a voice is to be tested, the student sings the five vowels on middle “C” into the protrud- ing end of atube. The sound waves of the tone enter a resonating cham- ber where the presence Flexible pins, do the driving ‘overtone is recorded. The test is repeated through each of the six- teen tubes and the records thus obtained clearly show the teacher on which vowel sounds most work is re- quired. ‘ 4 f Each of the tubes _regis- ters a certain overtone of middle “C” = or absence of the desired: canis imma Qatrsutctomct ona tT Hh Rs Mm ws" 2.53 oO OO eo Oo’ 2 8 tt COO = of Mm ao

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Lsaninnasisntian dita ANA RRS is iil 2 seit. aceneseeapriqnrsnninomas ennai nA ARI TI Canned Ostrich Eggs May Find a Market in London IGNS reading “Newly canned ostrich eggs for sale” may soon meet the eyes of the housewife looking into the windews of grocery stores in London. This statement is based on the fact that ostrich eggs are being packed experimen- tally in South America for shipment to England in liquid form. One ostrich egg is equal to about two dozen hen’s eggs. If the canning of these eggs proves successful, it will mean the salvation of the ostrich growing in- dustry which has suf- fered considerably as a result of the war. It will take a large family to con- sume one breakfast egg. Kneeling in Cotton Fields Made Comfortable by This Pad OTTON pickers have to work for C hours at a time kneeling upon the damp ground. They suffer tortures. To relieve them, Robert T. Jenney and Rudolph J. Langer of Monticello, Ia., invented a knee-protector. After the invention was perfected, it became ap- parent that it would be equally beneficial to miners, cement workers, carpenters and gardeners. The knee-protector is made of strong spring steel. It is just of the right height to place the foot in a restful position. The knee rests in a felt-padded hammock of leather or canvas be- tween the upper arms of the coiled spring while to the lower arms a metal shoe is fastened which is slightly curved upwards in front. The device is fastened to the leg by two straps, one above and the other below the knee. The construction of this humanitarian device is shown in the accom- Popular Science Monthly Delightfully re- freshing is a swim taken on this aquat- ic bicycle which has air chambers for buoying you up, a propeller for for- ward progress, and- a rudder for turning Ride This New Underwater Bicycle —It’s Great Sport at the Beach T the average bathing ccach about all you can do is swim, or paddle around in an old canoe. And so P. Kraemer of Jersey City, N. J., devised the underwater bicycle here illustrated. With this bicycle you can make as much as six or eight miles per hour, which is fast for swimming. But do you swim on a bicycle? You do on Kraemer’s, in a sense, for most of your body is submerged. The submerged fea- ture was especially desired by the in- ventor. effect of the water’s coolness on a hot day. He wants you to get the full The two tanks shown are of course filled with air, so as to support a rider of almost any weight. The handle- bars control the rudder. This contrivance should appeal to those for whom ordinary swimming methods are too slow. This aquatic bicycle may make the fish join the birds in wondering panying illustration. It should prove beneficial to many workers. supported by The knee rests in a padded hammock of leather or canvas coiled springs where man’s encroach- ments on other domains are to end.

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Home-Training for Wireless Heroes A phonograph and book of rules will help to qualify you for a radio operator’s post who may, during the din of battle, a | receive a message that will result i in victory for his country, or, from the deck of a ship, pick up an appeal that will save hundreds of lives, can prepare himself for such heroic acts by sitting in his home and listening to the records of a phonograph. And if he’s a faithful student, he may be able to prepare him- self for these pulse-stirring rdles in from three to four months. At the beginning of the course the student merely listens to the dots and dashes as they issue from the machine and compares them with letters and figures in a booklet. ‘n the first record each letter and figure is first announced orally and then signalled three times. In the second lesson he is initiated into the difficulties of punctuation and special signs, while the next step finds him struggling with sentences like this: ‘The quick brown fox jumped right over the lazy dog.” And from this reminder of his early school days the pros- pective operator is | S ie wireless operator of the future An ordinary telegraph key was used in making the records. After the student hag become familiar enough with the letters to recognize them as he hears the dots and dashes, he is advised to manipulate the phonograph so that they will reach his ears in irregular sequence, in order that his skill in receiving may be tested. The phonograph is employed for in- struction in sending as well as receiving, As soon as the prospective operator has become able instantly to translate the letters as they are produced by the phonograph, he is ready to begin practice with the telegraph key. The booklet accompanying the machine gives him information regarding the position of the hand and calls attention to common faults in transmitting. Simultaneous operation of the key and listening to records will develop evenness, accuracy and speed. Thus the student learns the preliminary essentials of how ‘to become a wireless oper- ator. What use he will make of the instruction will be shown when he . is placed in emergencies 910 q called on to in which men q translate of the radio , the dots and key fre- f | dashes of a quently find I | “‘press” dis- themselves, patch — sent In the course i just as. it of time his i would come ear will be- from the key come as of a veteran familiar with radio man at the dots and Arlington dashes of the or Poldhu. language of Static, inter- the air as ference from with ordi- other sta- nary speech, tions and the and his . reception of fingers will code words manipulate Pr: taken The upper picture shows the correct way of working the keys up in other the key. In the lower picture the student practices almost me: records. sending while listening to a message from phonograph chanically. lus in ex an ins th te lef fre th th ey al Fayeti et. > gpl ee, ann,

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_. Looking Through Your Hand An optical illusion and at the same time a H. Volta speaks interestingly of an instrument which he calls “The il- lusion of the hole through the hand”’ and incidentally points out the value of that experiment as a clinical test for cross-eyes and other defects of vision. Place before one eye, the right one, for instance, a roll of paper or a pasteboard tube; then hold the left hand, open, to the left of the tube, at a distance of about ten inches from the left eye. The right eye sees what is framed in by the tube; the left eye sees the hand. In the brain the images of the two eyes are fused to- Is a recent issue of “La Nature” With normal vision a per- valuable test single brain perception; we see double, a condition which is known scientifically as diplopia. The explanation is quite. simple, but, and this is the interesting feature of this experiment, one may deduct from it the most interesting clinical indications, which make it possible to combat from the start the cross-eyedness with which chil- dren are troubled so frequently and which parents too often: have a tendency to . neglect. Cross - eyedness de- velops in children gradually—so _ grad- ually, in fact, that the eyes become ac- customed to the de- fect and do not be- tray its existence by seeing double. ~ The functions of the eye with the less perfect vision are simply neu- tralized. When the good eye is closed, the poor eye sees; but son trying this experiment should see an apparent opening in the middle of the hand, as shown in the picture on the left: when the good eye is opened again the im- ages conveyed by the poor eye are again dis- gether; it seems as if the left hand were perforated by a hole through which can be seen the objects included in the field of the tube. What is the explana- tion of this curious phenomenon? When we look at an object, each eye sees it, but the impressions of the retinas are transmitted in such a way as to register but a single image in the brain. That is what the physicians express by saying that the rays emanating from the same object strike identical points of our retinas; the optical nerves leading from these points are combined so as to con- nect with a single brain cell. If some trouble affects one of the eyes, the points of the two retinas which have received impressions are no longer symmetrical; the two images cannot be fused into a 911 regarded by the brain. Although there is nc double vision, bin- ocular vision is no longer possible. By means of the experiment described it is possible to ascertain whether correct binocular vision is possible to the person tested. With normal vision the apparent hole should be seen in the middle of the hand. If the hand or the view in the field of the tube is not seen, one of the eyes does not see a, all, or its impressions are neutralized. If cross-eyedness exists, the hole will appear to the right or the left, above or below the hand. ~ The dis- tance at which the left hand has to be held from the end of the tube before the hole most nearly approaches its center differs according to the degree of cross- eyedness, and will furnish the eye special- ist valuable information.

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Photographing Holland in California New motion picture trickery, how it is done and how pleasing the results HEN the legitimate stage wishes \ \ to produce a scene laid in some foreign country all it relies on is a few painted sets and appropriate furniture. In motion pictures, however, the director has to find some means of building a real duplicate. An excellent illustration of the resource- fulness displayed in such matters is found in the construction by a film direc- tor of a Dutch village—in California! The buildings were simple enough; a rigid framework covered with papier maché, light plaster or even painted burlap being quite sufficient. But the canals and bridges were by no means so simply con- structed. Fortunately, however, the scenario did not call for any dives or marine disasters. Hence the canal was only a foot deep—just enough to float a small boat. The sides were constructed of wood, well tarred and caulked, and the earth in the stream bed tamped solid to prevent drainage. Then began the real camouflaging. It would never do, of course, for you to suspect that the scene was made in the studio loft, in spite of the fact that com- mon sense would tell you that it couldn’t have been made anywhere else. So the framework, as it were, had to be covered over and retouched until every detail was perfect. One of our photographs shows the result. The “bricks” on the sidewalk are thin strips of wood with loose sand sprinkled between. The tree was cut in a nearby field the day before this photograph was taken. The bridge, apparently of concrete, is simply wood covered with plaster. The flag paving on the bridge itself is merely wood grooved in irregular oblongs and squares Howe rane MM This picture shows how a motion picture concern built a Dutch village, canal, bridge, and houses in California. The framework is rigid, the rest mainly papier mache 912 aesgpseneetapecascmecam = wte 1 0 lUrSlUTTUCO*

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Popular Sevence Monthly Vimins ary It is hard to realize that this remarkably life-like Dutch village scene is all sham and deceiving trickery, built to serve only a brief while until the camera has caught it to assume the appearance of paving stones. The roofs of the houses are made of tiling and shingles laid on loosely and easily removed. For next week this village may be in Siberia, with a roof of ice, and the canal will be the road before the dismal village inn! What the Twenty-Dollar Gold Piece Has Been Through HE twenty-dollar gold piece has had an interesting career. Jewelers melt- ed it for their fine gold work, some forty years ago, and were very successful until the Government experts discovered the practice and stopped it in short order by “peppering”’ the gold with iridium. Fol- lowing this, unscrupulous persons at- tempted to. gather scrap gold by ‘‘sweat- ing,” or placing a number of coins in a bag and then shaking them violently, thus obtaining tiny particles of gold by friction. After these coins had been put through the “sweating” process it was an easy matter to pass them on unsus- pecting tradesmen and banks, provided, of course, that the victims did not weigh the coin. The amount of gold scrap obtained by the “‘sweating”’ process was so small that the bags had to be burned to recover it. Another way was to “‘strip” a coin by putting it into an electro-chemical bath, getting thereby a slight residue of gold on a copper plate, which was afterward melted and the metals separated. Be- cause this method discolored the gold it was not very popular. One of the most successful schemes, however, was the use of a specially prepared male and fe- male die. The diameter of the die was about one one-thousandth of an inch smaller than the diameter of the coin. It was so made that after the resultant rim of metal was cut off the milled edges remained. From a single $20 coin the gold thus obtained was worth about fifty cents, and the coin, to all appearances, had not been tampered with.

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914 Popular Science Monthly Turning a Bicycle Into a Railway Hand Car “TXLAG train No. 71, southbound, before it crosses the creek and make it back into siding to let southbound Special pass.”” Such was the order con- veyed by the ticker Making a Wind-Proof, Rain-Proof Chicken House from Piano Boxes \ \ THEN the United States Department of Agriculture is urging that every back-yard be the home for a flock of chickens, an inexpensive and novel plan in the little wayside / ~ station. “By George,” ex- claims the station agent, “‘this is an ugly fix! The creek ‘is five miles from here and No. 71 is due ‘here in half an hour.” ‘‘Look here, Jim,” interrupts his friend Harry; “Tony is sick and of converting two =) piano boxes into a poultry house be. comes at once prac- tical and advisable, The two boxes are placed back to back, three feet apart, the back and top of each res moved, a frame for roof and floor added, and the part between the boxes built in with boards will lend me that ww aot - —— : removed from the outfit of his. Ican A few turns of the hand turned this two boxes. The hit it up some and bicycle into a speedy railway hand car house is covered make the trip easily !”’ Jim eagerly approves of the plan. Tony consented to the loan and Harry “hit it up’ so thoroughly, that he reached the creek long before No. 71 came in sight. The danger of a collision was averted. Tony’s “outfit” was merely a bicycle equipped with an attachment invented by Agostino Rea, of Helper, Utah, which makes it possible to run the bicycle on railroad tracks. The device is simple of construction and inexpensive. At- with roofing paper which will keep out wind and rain. The piano boxes can be purchased for $2.50 each. The complete home for the poultry can be built quickly and easily for $12, It will comfortably house a dozen hens, The rear window provides ventilation and insures coolness in warm weather. Windows can be used instead of solid shutters so that the houses will be lighter when closed. A door can be cut at the end, covered with muslin to insure good ventilation. tached to the axles of the wheels of the bicycle are forked arms provided with grooved trolley wheels at their free ends. These forks can be swung down so that the trolley wheels engage the rail and prevent the wheels of the bicycle from leaving the track. A long arm, with a roller at the free end, is attached to the frame of the bicycle. When in use, the roller runs on the other rail of the track and acts as a brace to maintain the balance of the wheel. When not needed, the arms with the trolley wheels and the balancing arm may be swung out of the way and fastened. To insure dryness the boxes should rest on brick - supports and be surrounded by drainage gutters”.

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Popular Science Monthly thereby lifting the stern out of the water. A Four-Hundred-Foot Ship in a Three-Hundred-Foot Dock HE unusual feat of dry-docking a ship of four hundred and forty-six feet in length and a displacement of 9,300 tons in a dry dock only three hun- dred feet long and with a lifting capacity of 4,500 tons, was accomplished a short time ago, when the Japanese first-class cruiser Azuma, the propeller of which had been damaged, was docked for re- pairs in a floating dry dock at Honolulu. In order to carry out this undertaking, the dock was submerged and placed under the stern of the cruiser and then pumped out. It is said to have been the first time that this seemingly impossible feat was attempted. The result was extremely gratifying, and the remarkable procedure is sure to find imitators elsewhere. Thirty Million Collisions in a Day—the Earth’s Record : STRONOMERS have collected a great deal of material in recent years which seems to prove that there is an enormous mass of non-luminous comet or meteorite material scattered through stellar space. It is estimated that as The submerged dry dock was placed under the stern of the cruiser and then pumped out, This remarkable feat took place at Honolulu many as twenty or thirty millions of such bodies collide with the earth every twenty-four hours. Assuming a fairly even distribution of these cosmic particles in space, their quantity and number must be beyond computation. Clouds of such particles are now believed to be the cause of the dark and starless areas in regions where bright stars are numerous. It is assumed that clouds of meteorite material prevent us from seeing the stars beyond in these particular regions of space. The dark spaces in the Milky Way, the so- called ‘‘coal sacks” in the constellation of Sagittarius and many other starless re- gions are accounted for in this manner. Photographic star records made at Harvard and elsewhere during recent years have supplied much valuable in- formation to support the theory that the so-called new stars, also known as tem- porary stars, which flash out at points where previously no stars were known to exist, are stars which suddenly become luminous by passing through a cloud of meteoric particles. While passing through the cloud the faintly luminous star is in effect bombarded at high velocity by the meteoric cloud. The sur- face strata become heated and the lumi- nosity of the star increases rapidly.

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916 How the French Developed Their Newest Type of Battleplane OR a long time the principal French reconnoitering and bombing air- planes were only slight modifications ‘of the early Henry Farman type, well known in America. That airplane was stripped down to the last essentials: ailerons, elevator, rudder and a simple four- wheeled landing gear with rubber shock- absorbers (then a novelty). The pilot was perched on the front edge of the lower plane. A large fuel tank formed the back of his seat; directly behind it was the Gnome motor with a big, low-pitched pusher-propeller. That arrangement made a fuselage or hull impracticable. The big, double-control surfaces had to be carried by a wide open ‘“‘cage’”’ of poles (at first of bamboo) and wires. Farman was not a scientist, not an engi- neer, not an inventor, but a bicycle rider who knew what was practical in flying. When the war began, Farman’s homely type of airplane ousted the complicated Breguet biplanes and all the mono- planes because of its dependability. It was not improved much—simply given stronger, better engines, simpler control surfaces, some streamlining and an enclosed body for the aviator. All this was, of course, not sufficient to permit the development of modern speeds. From the very beginning the French also had some Caudrons, large biplanes, from which the modern type of speed air- planes was developed. In these machines the body was turned into a fuselage be- cause there were twin motors and pro- pellers out on the planes. A central

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Popular Science Monthly fuselage offered, therefore, the simplest mounting for rudder, elevator and-sta. bilizers. This developed in it the germ of a speed machine. Thus it came about that the Caudron forged ahead more~ayq more, as the science of aviation pro- gressed and developed. The accompanying illustration shows one of the latest developments of: this type, a true, up-to-date speed machine, Streamlining is proclaimed paramount by the form of the engine housings which are so arranged that they permit the wind to reach and cool the machinery. Other obvious proofs of minimum head regist- ance are the characteristic nose of the fuselage, the remarkably slender struts and staywires made vibrationless by holding two parallel wires against an intermediate piece of wood.

Appropriately Enough — A Band of Brigands Were the First ‘‘Chauffeurs” ERE is a justification for a bit of our American slang. It seems that the word chauffeur means “scorcher.” Over a century ago, some particularly brigandish brigands lived on the border- land between France and Germany. To force ransoms from their captives, these desperadoes grilled the soles of their victims’ feet before a fierce fire. So the countryfolk referred to the band as scorchers or, in French, chauffeurs. Not so many years back, when these same imaginative French were in need of a descriptive name for motor-car drivers, they hit upon the word chauffeur. Just how much “scorching”? of a more modern kind these up-to-date brigands of the road indulge in is best divulged by police records of fines for speeding. ©) Int. Film Serv.

This latest type airplane, intended for reconnoitering duty in the Marne sector, is just put together by expert workmen back of the French lines.

It is built for speed

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il ORAS in sty Popular Science Monthly Slip knot through flat loop in wire. Pass cord again through loop and aroundends. Bring it around and over other loop. Then the final lap and you simply slip it into the clip to hold it A Package Handle That Saves Your Time and Cord COMBINED package carrier and tier invented by Friedrich O. Vonto- bel, a Swiss resident of New York, prom- ises to be of considerable interest. The pictures clearly illustrate the con- struction of the device and its applica- tion. At one end there is a flat loop of wire in the same direction as the handle, at the other end a flat loop at right angles to the direction of the handle with another pend at right angles to it near the middle of the loop. This device saves time and cord. Be- fore the tying is begun a knot has to be made in the end of the cord used for tying. No other knots are required. The New Dandelion Ex- tractor. You Can Work It Without Stooping NEW device for pulling dandelions has been in- vented by Hans C. Johnson, of Fort Bragg, California. It has a curved scoop for penetrating the earth adjacent to the plant. Pivotally attached to the shank of the scoop and opposed to it is a small toothed digger, which, when it is swung to closed position, impales or binds the plant against the scoop so that it can be readily extracted from theearth. This digger is linked to a slidable rod contained with- in the main stem of the imple- ment. Two handles are pro- vided, one for the main stem and one for the slidable rod. Without stoop- ing, it is possible to ‘‘spot’”’ every weed and up- root it with this new extractor When the two are grasped and closed to- gether the rod is pulled upward, causing the digger to swing toward the scoop to en- gage the plant. It will be observed that the person using this device does not have to stoop to conquer. Incidentally it is a fine weapon for attacking weeds on the lawn. , Fasting Is Not What It’s Cracked Up to Be, Experiments Show T is impossible to stop eating and not feel the pangs of hunger. If you have been led to believe differently by the stories of men who have undergone fasting tests listen to the words of Professor Carl- son of the University of Chicago. He found as a result of observation on man during prolonged intentional starvation, that the view that hunger mechanism fails early does not hold as a general rule. The professional faster, he points out, may ignore the pangs of hunger in a spirit of bravado. Indian fakirs who have been practising the trick of fasting until the normal cravings of the body have submitted to will- power, are said to be able to go - without food forincredible periods of time. But probably the real truth of the matter is known only to them.

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Popular Science Monthly Saving Time in Insulat- ing Electric Cables inetd motion picture studio uses hundreds of yards of electric cable. It ig important that the cable shall not be damaged when it is walked on or when a truck should run over it. Electric cables are therefore wrapped to protect them— an expensive business. To simplify and cheapen the process, William T. Kearns, mechanical superintendent of the Balboa Motion Pic- Making a Gas Attack on the Pesky Ground Squirrel ULLY a score of men, each carrying a mysterious long-handled container resembling a churn with an end of hose attached, have reached the field. They do not march in close formation, but scatter in every direction, apparently in search of something. First one then an- other stops, puts down his churn, fumbles with the hose and then grips the handle of his churn and begins to The fumes of the volatile liquid are forced into the open- ture Company, has invented ings of the tunnels and kill every ground squirrel in them a clever device. Kearn’s invention consists of a reel attachment for a serving marlin, A reel of twine is held in a metal frame and the twine is wound off the reel around a marlin onto the cable. The marlin js nothing more than a wooden mallet grooved to fit against the cable, and the frame holding the spool of twine is fast- ened upon the handle of this marlin. The device makes it possible to bind the twine tightly on the cable. The device saves labor. In the older and more tedious method, one man did thewrap- ping while another work it up and down like the handle of a_ bicycle pump. Whatarethese men doing and why are they doing it? Is this war?— Yes, it is war—not against a nation, however, but * vagainst the ground squir- rel, feared because of its destructiveness and be- -cause it is known to be a carrier of the germs of the bubonic plague and other diseases. Under the direction of the United States Public Health Service these men are sent out to extermi- nate the ground squirrels by pumping the fumes of ey passed the twine around the cable. With this device one man does both. This picture shows how the new serving reel is used for winding ‘a cable by one man carbon disulphide, a high- ly volatile and inflamma- ble liquid, into the tunnels The inventor shows the old serving mal- . let and his improved dug by the squirrels. suhetitute for same an . tte ' date Mid. Gian

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Making Water Pump Itself A novel water wheel obtains its motive power from the current water from running streams, which is said to be both efficient and inexpensive in operation, has been in- vented by H. C. Berry, of Portland, Ore., and has been successfully tested. The wheel is primarily intended for irrigation in the arid districts along the swift-flowing streams of the West. Water wheels of many different designs have been invented and many of them have been tested by the experts of the De- partment of Agricul- ture. Their high cost or practical defects pre- vented their coming into general use. Re- alizing that the key to the effectiveness of the power plant is in the wheel itself and depends upon the. size, form, arrange- ment, number and depth of the blades, Mr. Berry made a thorough study of the subject and many experiments be- fore he decided upon the particular construction of the wheel he uses in his invention. The _y \ A CURRENT power wheel for raising CURVED BLADES OF WATER WHEEL => curved blades, which Power is transmitted from the water wheel to the pump by chain gearing are shown in the illustration, are the im- portant feature of the wheel. Each blade is removable and independent of the others,—a great advantage when repairs are necessary. The shaft of the wheel revolves in bearings resting upon the framework of the pontoon float, which carries, besides the undershot wheel, a force pump, driven from the water wheel by a sprocket chain gearing. Witha current velocity of only four miles an _ hour, two six-foot wheels, each forty-four inches si in diameter, developed 4—~—==—_ two and one-half horse- power, enough to raise two hundred gallons of water a minute to a height of twenty feet. Successful tests have been made in the shallow Clackamas River in Oregon. Tests on a larger scale are soon to be made. The cost of a plant that will de- velop about 100 to 115 horse-power in a ten-mile current, is estimated at from $2,000 to $3,000. The cost of operating the plant would be almost negligible, however. FORCE-PUMP DRIVEN BY WATER WHEEL j ae er e. a « ail ts JZ A current flowing at but four miles an hour will raise 200 gallons of water a minute to height of twenty feet. Two and one-half horse-power was developed in a recent test 919

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920 Popular Science Monthly Which Is the ‘‘Dead’’ Lamp on a Series Circuit? An Automatic Cut-Out Tells culties by providing a device which auto. matically cuts the filament of a “deaq” lamp out of the circuit and places a re. sistance in the circuit so as to maintain jt Contact closed and balanced. Thus the remaining point lamps in the circuit are enabled to glow on Connecting . The inventor winds a Tesistance coil plug around a resistance carrier within the lamp in such a manner that the: breaking or burning out of the filament will blow out a fuse. The spring held by the fuge is released, thus introducing the resistance in the circuit and bridging over the gap caused by the burning out of the filament, The trouble and inconvenience formerly caused by the burning out of a single filament in a circuit can thus be reduced to a bagatelle. Resistance circuit Filament , 9 y Filament - ae a enicnshngpetinsemigetnetine itty pase iinet lain Ra ane. Lighting circuit |e, Fig.2 Fuse circuit The Fifty-Seventh Variety of Armor FigS for the Modern Soldier Appears Resistance Figs. 2, 3 and 4 show the three circuits embodied in the lamp separately and Fig. 1, below, a diagram of the complete lamp HE soldiers of old went forth to fight. clad in cumbersome and expensive armor, which, while serving Fuse circuit Lighting circuit HEN an incandescent lamp which forms part of a series circuit burns out or when its filament breaks, all other lamps on that circuit are extinguished. The circuit must be bridged around the defective lamp. As all the lamps of the circuit are extinguish- | ed, it is a tedious task to find the exact lamp which caused the break. Each one has to be tested separate- ly until the burnt-out bulb has been found. Not until then can the circuit be restored, either by substituting a good lamp for the one burnt out or by bridging over the gap in the circuit. The incandescent | lamp recently invent- ed by F. Wybaillie, of New York, and shown in the accompanying illustration, aims to overcome these diffi- Clad in such armor our soldiers would indeed look like Martians or super-men as a protection, nevertheless hindered them from putting forth their best fighting strength. To-day, Martin Jelalian, an inventor of Rhode Island, has made it possible for a soldier to be pro- tected by armor. He is one of several dozen inventors who have reinvented the coat of mail. The device is a bullet-proof metallic structure which sur- rounds the body and extends from the top of the shoulders to below the thighs. This steel coat consists of two like parts held . together across the chest by means of straps. Hooks at- tach the coat to semi-cylindrical fit closely about the upper part of the leg, and are fastened be- hind by straps. The inner surface of the armor is padded. The head is protected by a lined mask comp of the same metal. pieces of metal which .

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oe oC. oe ee we ee SO ao wo he 8 Se _ e of t- 1 h . B; 1€ 1e f. How to Make an Air Operated Metal Punch for the Shop HE junk pile around a shop usually affords parts that may be of use from time to time. The SS ~ FOR PRACTICAL WORKERS hole was bored in the bottom through to the inside and a brass tube placed in it, care being taken to solder the tube to the zine: lining of the fireless cooker. Then a hole was bored in the running board of punch here illustrated was made from such material. As it was necessary to punch a great many holes in some braces used in cars at a rail- road shop, the master me- chanic made up plans for using an old 8-in. brake cylinder for the power which was taken from a wrecked freight ear. This cylinder was operated on about 100 lb. press- ure, and its power, applied through levers, punched holes 9/16 in. in diameter in rough stock \% in. thick. The _ controlling ‘mechanism was made from a globe valve, changed to act like a whistle valve, the connec- tions ‘being made the car to run the tube through. A wire rack was then made which came half way up the fireless cooker. Ice was put in at the bottom, then the rack and then on top of that the stuff to keep. In one trip this improvised _refrig- erator was so effi- cient that it kept the ice for three whole days and three whole- nights with the weather pretty warm. This was because the fireless cooker is pretty well insulated. Another little trick is to keep eggs while camping. These were kept in mighty good condition by placing them in a friction top tin which can be obtained at all camping supply stores. This tin is on the same principle as the to a pedal. Keeping Foods and Eggs Fresh on Camping Trips AVING a touring car rigged out for camping, it became a problem how to keep butter and meat fresh. This problem was very satisfactorily solved by taking a single fireless cooker and clamp- ing it to the running board of the car. A ‘ Metal punch operated by an air brake cylinder 921 littke tins in which you find spices and other commodities. First the tin was partly filled with groundcork. Thecork, the kind in which grapes are packed, can be procured at fruit stores. Each egg is put in sepa- rately so that one will not touch another and surrounded by cork. Each tin will hold 14 eggs. These tins can be packed closely in a box and there need be no fear of breakage as the cork will absorb all blows and shocks.

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Automobile Bearings and How to Care for Them Properly HE bearings of the automobile are, to many motorists, as a closed book, into which they have never ventured to peep—they have been content to The usual type of ball race with the ball holding ring and steel balls in place let the garage man “‘turn the trick.”’ Ina way this may be a wise course, but, after all, it is more satisfactory for the motorist to learn and know his own car than to motor in a depend-on-someone-else man- ner. The bearings constitute one of the most important features of the motor car and for this reason, if he is thoroughly to know his machine, the motorist must give some attention to the bearings. The bearings with which the modern automobile is equipped may be divided into three different classes—plain, roller and ball, the names themselves describing the types with considerable accuracy. Plain bearings—The plain bearing con- sists of a cylinder which is open at both ends and split down the sides. Generally it is made of bronze and has a babbitt, a soft metal lining, this being situated im- mediately against the rotating shaft. The babbitt and its supporting metal are securely locked together, and as a rule there are grooves, running crosswise of the bearing or at an angle, cut in the babbitt to permit of even distribution of oil. These bearings are used as supports for the crankshaft of the engine and also for the lower ends of the connecting rods —where they connect with the crank- shaft. There is also another type of plain bearing, consisting of a bronze cylinder, without the babbitt lining, these usually being called bronze bushings. These are 922 Popular Science Monthly found at the top of the connecting r in the clutch, on the brake pedals, etc., op any other place where there is little dap. ger of excessive heat being generated, When the babbitted plain bearing be. comes worn, the result is generally knock within the motor. When this oe. curs it may be remedied by removing a shim, a very thin piece of metal located between the two halves of the bearing, or filing away part of the metal where the two halves touch. A laminated shim jg made consisting of many thin steel layers and by removing one or more of thege the offending looseness or play may he taken up. This babbitt-lined bearing requires perfect lubrication, for if the bearing is permitted to run dry excessive heat is generated through friction and the soft metal is quickly melted, or burned out, this being denoted by a pounding in the motor. The burnt-out or worn bearing should be replaced or repaired at the earliest possible moment, otherwise 4 ruined engine may result. Roller bearings—These are cylindrical in form and vary in length. Each con- sists of a series of steel rollers which form this cylinder, and is divided into two main divisions—straight roller and _ tapered roller. There are radial roller bearings and thrust roller bearings and combina- tions of the two. These are generally Mey BETH. A roller bearing and its sleeve which is used on larger and longer shaft surfaces used in the rear axle and rear wheels of the automobile. If one roller should be come worn an entirely new bearing should be installed, for if all the rollers are not the same size the accuracy of the complete part cannot be maintained. Ball bearing—This consists of steel balls which revolve between two holders or races. This is the most flexible bearing

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ll ER he Bee Sh ted a Hea © cS sa Sree ee aa2e sear e and it consumes very little of the ai passing through it. The ball bear- ing is divided into several classes. There is the annular ball ; bearing, which has races in the form of rings, and there is also the bearing which has a holder or race “,” shape, with curved sides facing the balls. This 's known as the cup and cone ~ he A : Z * md ¥ P Connecting rod end with a split babbitted . bearing that can be readily replaced bearing, and these are adjustable, while the annular bearings are not. This type of bearing is also classified according to the way in which it carries its load, as thrust or radial. Ball bearings are built which withstand both radial and thrust load.. Then again, bearings of this char- acter are built which have two rows of balls. To work properly these balls must not vary in size more than one ten- thousandth of an inch. If one ball is worn through under-lubrication all of the balls of the set should be repiaced with new ones. While oil is used to lubricate the plain bearing, medium weight cup grease should be used for the ball and roller bearings, and the best grade of grease is none too good. Every time the bearing is removed from the car it should be washed thoroughly in kerosene and dried on a clean, dry rag. The bearing should be kept free from water, dirt, grit, or other foreign sub- stance, any of which might be sufficient to ruin the entire bearing assembly. Be- fore replacing the bearing, after it is washed, fill it with new, clean grease. Caution should be exercised in tightening the bearing in its housing. See that the nuts are turned down evenly so as not to cramp the bearing in any way. The operator should never hurry in replacing the bearing. He should see that every step in the work is done right before proceeding. Popular Science Monthly 923 Strengthening Hammer Handles with Steel Strips CLAW hammer of the usual kind with a wood handle may be made very strong for heavy work, such as pulling very large nails. This can be done by sawing out an opening in the handle from the hammer head back past the center of the handle an inch or two and inserting a strip of very narrow old steel buggy tire and securing in place by drill- ing small holes through both handle and buggy tire strip. The proper place for the holes is just back of the hammer head, one in the center, and one just back of the center an inch or two from the end of the buggy tire strip. Sometimes the drilling may be dispensed with by selecting a strip of buggy tire with bolt holes in the proper places. A Wall Hanger for the Ordinary Electric Lamp Stand HE illustration shows a simple de- vice for using an adjustable elec- tric stand lamp as a wall lamp at the head of bed or couch. The de- vice consists of three strips of wood screwed to the wall in the shape of a half hexagon and three narrower strips nailed on to them so as to extend over theinner edge, forming a groove into which the base of the lamp can be inserted and held firmly. Being ad- justable, the lamp affords a reading light at whatever angle the person reclining on the couch desires.—F. L. CLARK. The desk lamp as it hangs on the wall An Inexpensive and Effective Aluminum Polish HE following is a fine polish for aluminum ware. It is made by mixing ammonia and water in equal quantities, and then adding the mixture to sufficient borax to make a paste about as thick as paint. Apply with a thick soft cloth and polish with canton flannel.

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924 Popular Science Monthly Constructing a Convenient Table for the Porch ORCH furniture to be worthy of a place on the bungalow porch should pe ' Bites a olestab as es ts sst ee saee ! traypee oot ates 6 =H H ' te ' " ' ' ' -! ! z] L wapacae scacdghee ee ee ee! Ba tou ates then obtaining the angle with a bevel, The top pieces should also be cut and fitted together with a cross lap joint Fasten these together with the two No, 8 flat head screws. It is best to glue the top up, using about four pieces to overcome any tendency to warp- ing. Join the edges with glue and doweis, using about four dowels to each joint. While the glue in the top is drying assemble the supporting part, Bore 14-in. holes in the top and bottom cross-pieces where the legs are to be fastened, and countersink the holes. Before fastening the legs with screws nail them in place with the 4% Pleasing design of a porch table that can be made of = any sound wood and coat- 30° 25% ed with white enamel of type. The table de- scribed here is different possess individuality | finishing nails and then insert the screws. Draw the screws up as tight as possible, and the table parts will be held together solidly. The top should be planed and then scraped and cut out to size on a band-saw. Smooth up the edges and surfaces care- fully with sandpaper. The top is then fastened to the.table with screws run up through the cross-pieces. The holes for the from the conventional pe tt porch table and has af balet+— distinction of its own. | 24 rit : \j— +04 screws had better be slotted and a washer put under the screw The following bill of Details of the parts for heads so that the top can shrink material gives the re- making the porch table and expand readily. After the quired pieces in lengths in a convenie to make a cutting fit. 4 legs 27 in. long by 2 in. square. 2 lower pieces 25 in. long, 234 in. wide and 2 in. thick. 2 cross-pieces 2214 in. long by 214 in. wide and 1% in. thick. 4 top pieces 25 in. long by 61% in. wide and 13g in. thick. 12 14-in dowels 3 in long. 4 No. 8 flat head screws 1 in. long. 8 No. 14 flat head screws 214 in long. 4 No. 12 flat head screws 2 in. long with washers. 4 casters. Small quantity of 214 in. finishing nails. Saw out the two lower cross-pieces first and fit them together in the center with a cross lap joint, fastening them with two No. 10 screws. Next proceed to cut out the legs by squaring them up to size and cutting the ends to the correct angle. This can be found by drawing the table full size on a piece of wrapping paper and nt size entire surfaces of all parts have been well smoothed with sandpaper it is ready for finishing. White enamel makes a very fine finish for porch furniture. It is applied as follows: First put on two coats as a base, allowing time for drying thoroughly between coats; then apply the finishing coat. Allow three days for the last coat to dry. Then the table is ready for use on the porch. As the wood used in its construction may be of any soft variety it is not difficult to make and join the parts snugly together so that there will be no seam to show after the surface is coated with the enamel. The same table can be made in quartered oak and stained to match furniture for a room, or constructed of mahogany or birch stained mahogany and used with other furniture to match for the home. The design is such that it will adapt itself for use in either case.— HARRY W. ANDERSON.

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‘concrete, and

A Garden Barbecue

An outside fireplace with the added feature of grids for grilling fresh meat By Huntington Baker HE out-of-door fireplace has become T a popular feature with many of the more luxurious dwellings of the West. This is usually designed to form a part of the terrace or veranda of the house, and its purpose is manifestly to combine the western country estate. This model is a practical one, not too expensive, and com- paratively simple in construction. It requires about 1,700 bricks, with 3 bu. hydrated lime and 1 cu. yd. of sand for the mortar. The fittings may be secured from a_ black-

cheer and com- fort of the open fire with the fresh, free air of the out- side. Where the grounds are extensive or se- cluded enough to permit it, a somewhat dif- ferent style of open-air fire- place has been designed, to be

smith. At A is a~ wrought iron collar- strap 3/16 in. by 34 in. made to fit around the keystone which projects to receive it. At B are two l4-in. eye-bars anchored to the soffit of the arch, which

built generally in a clearing, apart from any building. The charm of this feature lies not only in the comfort accorded those * who gather ‘round, but in the fact of its being so con- structed as to provide also, every detail — necessary for the preparation of a steaming-

The open-air fireplace on the grounds of an estate where barbecues may be held and refreshments served form, with the collar-strap, loops from which may be suspended wires or chains to hold a kettle or cauldron. At C are two iron hooks built into the S44 joints of the brickwork for supporting the ends of an iron rod placed “o across the opening to serve as a

ae t

a

spit or as rests

hot meal. The garden barbecue may

for the ends of long forks or prongs thrust

be built of ~* stone, brick or is adaptable to slightly different forms of ornamentation. The accompanying measured drawings have been made from <a typical brick brackets. example now standing in the grounds of a

Plans of the fireplace giving dimensions of a good size to cook food sufficient for any entertainment 925 agers & into the fire. one waa At D are shown two shelves or - grids made from cor- rugated wire mesh set into a frame which fits snugly into the grate on angle- These grids are removable and serve also for use in the smoking and

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926 grilling of fresh meats. Attached to the main body of the barbecue is a shelter for fuel. At E, sheet-iron strips are used to support the bricks of the roof. To one who has a general knowledge of M Front Section Skeleton framework for building the bricks over in making the barbecue fireplace brick-laying, the making of such a barbe- cue is no great task. Special care should be taken with the semicircular arch which is turned on a wooden templet or center- ing, shown in the diagram. The faces of the centering are composed of two pieces of 114-in. planking, sawed to the proper arcs as at F and braced at the bottom with ties, G, and at the top with fish-plates, H. Across the face pieces are nailed lagging-strips 114 in. thick by 2 in. wide and 2 ft. 5 in. long. The face pieces rest on caps I, under which the supports, K, are placed. The centering must be made shorter than the actual height of the opening to allow its base to rest on two slip wedges, L, which are loosened after the masonry has set, thus allowing the arch to settle down gradually to its own bearing. The wedges when withdrawn also allow for removal of the centering without injury to the bricks. The braces, M, are inserted between the cleats, O, to hold the supports in a vertical position against the jambs of the opening. The chimney is corbelled out in the rear so as to allow Popular Science Monthly the flue to start at a lower level, thus W making the draft more efficient. of course the height of the chimney is vari. able, according to conditions, but 9 ft, ig a good height for ordinary circumstances, A brick hearth in front of the fireplace is an added convenience. Such a fireplace can be built in a wall on the back yard of a lot or where the grounds are small and form a part of a garden bric-a-brac. In this instance the dimensions can be changed to suit condi- tions. Cow Horns Effectively Used in Library Table and Chair NOVEL use for cow horns has been , discovered by an ingenious crafts- man. He has found a means to use them for making furniture. The illustration shows that the result is not only practical, but presents a unique and decidedly ornamental library table and chair. The horns proved adaptable as well as very substantial. They are tastefully mounted with copper, and in the table form the entire upright con- struction, the quartersawed oak boards having no other support. In the chair the same general plan is followed, the horns being used as the support, and riveted together at the top to form a comfortable and well shaped back. The lines of both table and chair very closely resemble the design followed in Oriental furniture. Both pieces are rigid, and have A very effective use of cows’ horns in the con- struction of a library rocking chair and table been tested to stand a heavy strain. They form a pleasing addition to any library or den, their novelty attracting attention.—L. N. JOHNSON. eack lowe fron fron and gag righ

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Sr tn AS heel see sy 2 Open Canoe Cruising IlI.—The construction of the lee boards, their location for handling the canoe under sail. Stowing outfit, making a landing and the canoe as a fishing craft By E. T. Keyser will be needed. Square up two pieces of 34-in. mahogany, oak or cherry, each 30 in. long by 12 in. wide. On the lower left edge, make a mark 11% in. from the lower left corner. Lay a line from this point to the lower right corner and saw along this line. With a marking gage, run a line 334 in. distant from the right edge at the top. On the right edge, [’ order to sail to windward, lee boards The lee boards as they are fitted to the canoe gunwales for sailing to the windward mark a point 101% in. from lower right corner and, with this point as a center, describe an are with a 12-in. radius from the bottom of board to the line which runs parallel with right edge. Cut out this are with a compass saw and rip along the parallel line from the top of the board to the arc. From the waste, cut out two pieces each 334 in. square and screw them to the head of the lee boards as indicated in the cross section view. Through center of this square, bore a hole 114 in. diameter through both lee board and reinforcement and round off the tops of lee boards as shown in Fig. 15. Work down the front edge of the lee board as shown in the cross section; apply a couple of coats of linseed oil with a soft cloth, allowing the oil to soak well into wood between coats, and finish with three coats of varnish well rubbed down be- tween each coat. The lee boards are fastened, one to each end of a 11%-in. axle, by means of sash pins for which 927 holes are bored through both tops of lee boards and axle and are held to the canoe by two straps passing around the ends of the axle and thwart, as shown in illustration. A brass tube long enough . to reach from gunwale to gunwale and encasing the axle would allow the lee boards to lower and rise more freely, with tighter buckling. of-the straps. A halliard, leading from one ofthe sash pins to a small cleat fastened to the in- wale, on being pulled in will lower the boards for going to the windward while their buoyancy will cause them to rise when the halliard is cast off from the cleat. Pulling out the sash pins allows the removal of boards from the axle and the whole outfit stows compactly when the canoe is under paddle. The proper location of the lee boards, the position in |. which they al- !2i low the canoe to do the best windward work, is best found by ex- periment. Should the best location lie between the thwarts, a pair of large brass screw- eyes may be set into inwale to take the holding straps. The princl- Details of a lee board ples of sailing for use in canoe cruising a double rig canoe may be easily understood by studying Fig. 16. In A is shown the tendency of the wind pressure on the mainsail to make the canoe _ pivot on her stern and throw her bow away ~ from the wind, increasing the tendency to capsize. In B is shown how the pres- sure of the wind on the dandy tends to cause the canoe to pivot on her bow and

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928 Popular Science Monthly face the wind, reducing the wind pressure. The mainsail may be regarded as the driving sail and the dandy as the means by which one may round up into the wind and spill the pressure which may threaten to overturn the canoe.. This is accom- plished by letting out on the main sheet and letting the dandy act as the after —— — oo Fig 16 wind on dandy “| Stern The principles of sailing, showing the tendency of the wind on the mainsail portion of a weather vane, whenever the wind becomes too strong. A canoe rigged as in the previous article will always tend to point up into the wind and spill the pressure, and can only be kept from luffing by means of the steering paddle which is carried over the same side of the canoe as that over which the main boom is swung at the time. To hoist sail, trim in dandy sheet so that the boom is amidship, push away from the beach or float. Hoist the dandy and when the canoe has swung around with its head to the wind—and not be- fore this—hoist the mainsail, letting the main sheet be free. Then let out the dandy sheet, pull in the main sheet until the canoe has headway and, when you have gathered steerage way, enough speed to allow of steering, point the canoe on your course. Never lower the dandy first. Always head up into the wind, lower the mainsail and then the dandy. When going about, coming back over the same course that you have sailed, turn the bow of the canoe against and not with the wind. The correct method of doing this is shown in Fig. 17, The arrow shows the direction of the wind The canoe with a beam wind, is shown at.A and when the canoe is headed into wind, as at B, the wind is spilled from Sails and booms amidship, and C shows’ the canoe with the booms on the opposite side and retracing her course. Note that at any time between positions B and C the canoe may be luffed up into the wind and the pressure spilled. The improper method is shown -at Dand E. At D the sails must catch the full force of the wind and the location between D and E; the booms must go across the canoe with a “‘flop” which may capsize her. “Gybing’” it is called. Furthermore, at no point between A and B can one ease up by luffing and one must take the full force of the wind without ability to spill any of the pressure, A long narrow and light boat, like an open canoe, has very little momentum when rounding up and some help from the paddle may often be necessary be- tween positions B and C, but do not he tempted to adopt the other method. To go about, slacking up on the main sheet and easing up on steering paddle are all that are necessary. When sailing with a beam or a stern breeze allow the lee boards to rise. When tacking, lower them by the halliard. Always have them raised when paddling as they cause con- siderable drag. Sailing dead ahead of the wind is the most ticklish: part of canoe navigation. The area of the sail that a canoe can carry ahead of the wind is what governs her maximum spread, as the canoeist’s weight in this case cannot be opposed to the wind pressure. Also, there is the tendency of the sails to gybe at the slightest shift wind or variation of the canoe’s course. This tendency may be recognized from a desire of the main boom to raise or “hike” and should be promptly counteracted by steering a bit away from the side over which the boom is laying. With the wind directly astern and both booms on one side, the dandy will blanket the mainsail to 4 certain extent and there will be more of a tendency of the canoe to round up. This necessitates carrying more pressure

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Shinra athiNib res: envitmcn kei ispainanionliipbiadiaite Mlshthi the headway. on the steering paddle which diminishes It is therefore good sea- manship to carry the sails “wing and wing” or with the main boom over one side and the dandy boom over the other. This allows both sails to draw to their full capacity and also reduces the drag from the steering paddle. In event of a tendency to gybe, keep the mainsail full and let the dandy do the gybing as its area is so small that it will not cause wind -~--—-— Pa -.~ - ~ mm t= oe, f g = - any damage. Often it will be possible to tack against or take as a beam wind one that is too heavy to run before with the full A rig. When it be- comes necessary to run before it, round up, lower the main- sail and then scud before it under the dandy alone. In very heavy weather, the canoe may Bow Fig.17 Turning meth- ods in a course be turned stern first, the dandy sheet unrove from the deck ring and held in one’s hand and the canoe sailed stern foreward under the dandy only. It is well to experiment with the canoe rigged thus, so that you may know just where to place the lee boards so that they will be correctly located for the dandy in this position. When sailing with a passenger, both of the crew should face forward and the passenger given the management of the lee boards.. It is better that the steers- man handle the main sheet as he can co-ordinate his actions with paddle and Popular Science Monthly Bow 929 sheet better than two parties could possibly hope to do. With an outfit aboard, it is best to have considerable weight up forward, if much tacking is to be done, as a canoe somewhat down by the head will make better windward work. The reverse will hold for a long run ahead of the wind in’ which case it is best to have more weight aft. A passenger, serving as live ballast, can prove quite useful in this respect. In making a landing at a float or dock, always come up to the landing against the wind or tide, whichever may be the stronger, and when leaving the canoe temporarily tied to a landing, tie her on the side away from. which the wind is blowing so that she may ride clear with- out bumping or scraping. Often, when a light breeze is blowing, the hoisted dandy with boom trimmed amidships will keep the canoe well off the landing against a tide which would tend to run her against the float or dock. C When landing on a beach, except on a falling tide, always pull the canoe well above high water mark, as you may be away from it longer than you had figured upon and a rising or shifting wind might pound her on the sand. When landing on a rocky shore, un- less you can be sure of enough sandy bottom to accommodate the canoe, step overboard and wade ashore before the canoe touches bottom, dragging the canoe until she grounds. Unload her before dragging her up on the beach and load her with only the bow grounded when you embark. Dragging a heavily loaded canoe ashore or down a beach will do her more injury than five seasons’ legitimate usage. One of the chief beauties of a canoe is her adaptability as a fishing craft. With her one may hoist sail, run out to the fishing ground and return under canvas while the other anglers are raising blisters on their hands. For fishing, it is best to have the canoe anchored by the stern, as then the fisher- man will face the direction in which his line is pulled by the tide or his float is blown by the wind. After the mainsail is lowered, the boom may be removed from the mast and the forward end of the sail pushed up under the forward deck

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930 Popular Science Monthly and the after end laid across a thwart out of one’s way. The dandy, having a lazy jack, will take care of itself and give no trouble. It is well to have a rod long enough to allow the line being passed from side to side of the canoe at will, by passing the rod tip over the main mast head and carrying the line across the bow. This is easily accomplished as the canoe is anchored by the stern. If the fish run to any size, a landing net will prove a great convenience and save many fish. Fishing in a small river, such as the Delaware, the stern anchor is a necessity as it allows one to drift with the current and drop anchor and raise it without changing the downstream direction of the bow. (To be concluded) Wing Attachments on Shoes to Aid the Swimmer EING denied the privilege of entering into a swimming contest because he was too young, a boy determined to beat the winner at least and this is the way he did it: To an old pair of tennis shoes he attached the wings as shown in the illus- tration. A sole of wood, A, was attached Wings fastened to a wood sole on a tennis shoe to make an aid for fast swimming. They won a race for the wearer to each shoe and in its center a vertical piece, B, was securely fastened. These pieces were cut slightly tapering toward the top. Wings C were attached to the wood soles with hinges so that they would lay against the vertical pieces. A chain was attached to the lower end of the vertical piece and to the wings so that they would come to a stop at almost full spread. It is obvious how these wings worked as the swimmer made his strokes, On the day of the race the boy hid the prepared shoes in some long grass near the shore and when the contestants started he quickly undressed, slipped on the shoes and easily beat the winner over the course.—WM. R. HUNN. A Fishline Float Made of an Ordinary Thread Spool ITH a float of this type I find the operation of taking on and off q line, as well as of setting for depth, is A thread spool shaped and fitted with a tapering pin to make a fishline float accomplished much more quickly than with other floats I have used. A small or large spool, Fig. 1, is trimmed out as shown by the dotted lines, into the shape of Fig. 2. A fine saw cut is made until it connects with the hole in the spool. Through this cut the line is inserted and fastened with a taper hardwood plug. The float can be painted or not, but both float and plug must be given a coat of hot paraffin inside and out. Convenient Material for a Bait- Catching Net HE fisherman who angles only oc- casionally usually neglects to supply himself with a bait catching net, and so at the last minute has to seize on the nearest fabric that will not hold water. If, however, he visits the nearest produce market or grocery store and fora few cents buys one of the ventilated sacks in which onions are shipped, he will have material for either a bait catching net or landing net. These bags are strongly woven in 4 in. mesh and will furnish a square of material about 31% ft. by 34 ft., which can be conveniently attached to any net frame. Evidently any material strong enough to hold onions will prevent a fish from breaking it.— JAMES M. KANE.

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Banding a Tree Trunk to Catch and Destroy Moths HEN the codling moth larva has done its best to destroy the ap- pearance of the ripest and rosiest fruits it can find, it seeks a place to spin a cocoon, and for this purpose it generally crawls up or down a tree trunk. Hence the usual method of trapping the moth is to wrap a band of burlap around the tree trunk. An im- ‘provement on this method, devised by E. H. Sigler, of the United States Bureau of Entomology, employs a wire sereen over the burlap band to form a trap into which the larva enters and spins its cocoon, but from which it cannot escape as a moth. To make the trap, strips of burlap six inches wide are folded into three thicknesses. The loose bark from the lower branches and trunk of the tree is removed. A strip of this burlap is folded once around the trunk and held in place by large tacks, driven in such a way that the edge projects about one-fourth of an inch beyond the burlap. Black- painted wire screening with twelve meshes to the inch is then cut into strips six inches wide, and the edge of each strip is folded twice, allowing one-fourth of an inch to each fold. The strip of screening should be long enough to allow for an overlap of three to four inches when placed around the tree over the burlap. It is tacked to the tree so that both the upper and lower edges fit snugly against the bark. The projecting tacks used to fasten the burlap prevent the wire from pressing against the cloth. To make sure that no moths can escape through the openings along the edges of the trap or along the flap, a thin coating of pitch tar may be used. The traps may be placed on the tree during the winter or in the spring, not later than one month after the petals have dropped. A burlap band covered with a wire screen Popular Science Monthly 931 Cleaning the Gilded Portion on Picture Frames ILT picture frames and chandeliers will, in the course of time, get dirty and turn black. Procure a box of wall paper cleaner and rub some of it over the gilt frame or chandelier. This removes the grease and dirt. Next boil some onions in water so as to get a strong solution. Dip a soft cloth in it and wipe over the frame, polishing with a dry cloth. Cooling Camp Food by the Evapora- tion Method i ee from an ice supply it is often difficult to keep:the food in good con- dition when no spring is near. However, a very efficient refrigerator that will go a long way in keeping the camp food fresh can be made from a small wood box mounted on stilts as shown in the illustra- tion. Shelves and a door are put in to hold the various dishes. The whole is then covered with flannel which reaches down into the water below. Box Flannel = COVEFING \ \\i \V \\ \\\ i\ q Supports Flannel in water Wood box cloth covered and mounted on stilts in a brook to keep food by evaporation The evaporation from the cloth will cool the contents of the box in a very efticient manner. Such a device also keeps the food away from the crawling things that infect the woods.—THOs. W. BENSON.

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932 Popular Science Monthly A Rocking Board See-Saw for Chil- dren’s Playground HIS excellent piece of furniture for the playground or porch may be easily made of a board and segments of A board with attached segments of a wheel rim making a see-saw rocking board for the children’s playground rims from a discarded carriage wheel. The board is rounded as shown and the segments set in the board edge. Support- ing strips may be used under the board and across the lower part. These seg- ments are slightly set out, as shown, to make it rigid. Old Tin Fruit Cans May Be Used over Again WING to the scarcity of tin, patent cans for preserving fruit will be ex- pensive for a time at least and difficult to obtain. If one is careful in opening the cans of fruit and vegetables purchased from the grocery store the cans can be used in the following manner: Thorough- ly clean and dry the cans as soon as con- tents are removed and store them away in a dry place to keep them from rusting. When ready to use them again fill the cans to within 4 in. of the top and then pour melted paraffin in to fill them. Tie covers on of waxed paper and the contents will be preserved as well as in the patent can or glass jar.—L. GERMAINE. An Overhead Dove-Tail Suspension for Table Drawers je method of hanging a drawer here illustrated will be found a simple and satisfactory way out of a difficulty which is often encountered. This way is practical anywhere where a light drawer, such as is used in library tables, sewing cabi- nets, and the like, is to be placed in a limited space and a bottom slide and rail are either not possible or undesirable. The construction simply consists of .a dove-tail tongue engaging in a cor- respondingly shaped notch in the upper edge of the rear end of the drawer, the tongue being fastened ej- ther direct to the table-top or to blocks, if the drawer does not come right under the table-top. In front it runs on two pins driven into the table-legs and set back about 1 in. to be out of sight, or, if the drawer does not oc- cupy the entire space between the legs, on a couple of small steel plates screwed IN DRY WEATHER IN WET WEATHER ————— LE A ~ = Plead 7 . l= ——————————— a | — =H — = — J STEEL PLATES A dove tail table hanger for a drawer to eliminate the sticking drawer slides to the edge of the side-ends and protrud- ing about % in. This way of suspending a drawer has many advantages. It is extremely simple —_— a ae” oe ai [| le

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and requires very little work, and it gives the greatest possible amount of usable space. If properly put in, it will never pind because the points of contact are small and any swelling or shrinking of the working parts are automatically compen- sated. ‘Therefore, an extremely close fit can be made without any fear of trouble later. This method is far superior to the usual way of hanging such drawers by grooves in the sides which engage tongues, and where any slight warping or swelling of either side or tongue immediately pro- duces binding, unless a very loose fit has been made. It makes for good appear- ance, too, there being no unsightly grooves to show in the sides when the drawer is pulled out.—_ HENRY SIMON. How to Make a Pocket Plumb and Level in a Block HE only materials necessary to make this most serviceable little tool are a plain level glass and a small hardwood block. The block should be from 1% to 54 in. thick and triangular in shape, the angle of one corner being a right angl, andthesidesequal. _ Draw the hypoth- = enuse and on it mark the center of the sight-hole. | Through this, and ° parallel with one side, draw a line and square it across one edge. Mark the center and bore a hole just large enough to admit the level glass, keeping the bit straight by sighting along the pencil line. The bore should go just deep enough so that the center of the level glass will co- incide with the center of the sight-hole. Now bore the sight-hole with a 34-in. bit. Put a few drops of glue into the end of the bore for the glass, slip the glass into place, drop a little glue on its end, and seal the hole with a dowel. The level should now be left untouched until the glue is set, and then the edges trued up with a block-plane, care being taken to true up the long edge also. This level is very light and fits the A level glass set in a triangular wood piece Popular Science Monthly 933 pocket. It accomplishes with one level- glass what it ordinarily takes two to do and not only that, but it permits truing- up work. inclined at an angle of 45 deg. to the horizontal, which is at times ex- tremely useful. It has another advantage, too—it can be used to lay out miters when no other tool happens to be at hand. —HENRY SIMON. Making Camp Hammocks from Gunny Sacks ERSONS contemplating camp life during vacation in almost inaccessi- ble spots may, with a little forethought, Two bran or peanut sacks sewed together with a hanger at each end for a hammock provide themselves with some of the luxuries of the home. For instance, the hammock, which is difficult to carry, can be made from large bran or peanut sacks in which the outfit may be packed for transports. At the camp cut round sticks as long as the sack are wide, attaching a strong cord for a hanger at either end and drop one into the bottom of each sack, passing the cords out between the meshes at the corners. Sew the tops of the sacks together with strong twine or string and the result will be a hammock that, when suspended between two trees, is a near approach to a spring bed. The sacks may be used for the duffle on the return trip—GALE PINCHNEY. A Cement for Mending Valuable China Dishes ALUABLE china may be mended with the following mixture, and when dry it will resist hot water and ordinary usage. Mix a teaspoonful of alum and a tablespoonful of water. Place in a hot oven until it is quite transparent. Wash the broken pieces in hot water, dry and put them into the oven until they are warm; and while still warm coat the broken edges with the mixture thinly and quickly as it sticks instantly.

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934 _ Popular Science Monthly Stakes with Guide Lines for Hoeing Garden Beds REQUENTLY the gardening enthu- siast plants the seeds and then forgets all about them. When next he views the patch he is unable to tell the weeds from Hoed ground A line around the stakes furnishes a guide for hoeing small growing plants plants. Here is a sure plan that will enable him to hoe out all the weeds possi- ble without cutting the little plants. Always mark out the ends of each row with proper stakes, marking the stakes with indelible pencil with the name of the plant in the row. When hoeing or weed- ing time comes, run a chalk line along the rows from stake to stake as shown in the sketch. This will give a guide line alongside of which one can hoe as close as he desires. The remaining weeds, being mixed with the plants will, of course, have to be weeded out by hand to pre- vent their injury.— JAMES M. KANE. A Combination Camp Kitchen Cabinet and Table HE combination cabinet and table illustrated was the result of the re- fusal of my family to take a long outing unless they could carry some conve- niences with them. “‘Roughing it’’ did not appeal to them. The table will accom- modate four persons comfortably and extra compartments may be added as required. The box is made of 14-in. material 30 in. long, 14 in. wide and 12 in. deep at the sides, and 121% in. deep at the ends. There are two hinged wings, each 2814 in. long, one 13 in. wide and the other 13 14 in. wide. These are hinged to the upper edges of the side boards. On each end of each wing is an L-shaped piece of meta] ¥ in. wide and \% in. thick. These are fastened with screws, making the Wings 29 in. long over all. These iron pieces are put on so that the end not fastened to the wing will stand in a vertical position as the wing hangs out from the box. The cover is made of sheet metal with the edges turned down and the corners riveted. ‘The inside measurements are such that when it is slipped over the top of the box it will fit snugly. The upper ends of the vertical pieces of metal fit into the corners of the metal cover when the wings are extended and will prevent them from dropping farther than a horizontal plane. The inside of the box may be arranged to suit the individual builder. On the ends of the box are fastened blocks of wood cut as shown. A metal strip is fastened across their faces to form a pocket for the upper ends of the legs, Two saddle strips are also fastened to the ends to slip the legs through as shown. The metal cover has two clips fastened to lron strap A camp kitchen table and cabinet for mak- ing almost every convenience of the home the ends. These clips project and form a hook to catch under the blocks for the upper ends of the legs, and hold it in place when folded for shipment. When opened up as illustrated it pro- vides a raised table top and two wings. This leaves the contents of the box ac- cessible while at lunch.—J. D. BOYLAN. | > lt = ae = ee = ade = ey me pte rm FH Sse ct di

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en Simple Designs for Sheet Metal Working XIII.—Other interesting problems developed by means of radial lines By Arthur F. Payne Director of Vocational Education, Johnstown, Pa. the radial line problems as demon- strated in the last two issues will have acquired an understanding of the fundamental principles of the methods of pattern development by means of radial lines, that will make these more complex problems easy to understand and develop. The new points introduced in these T ites of you who have worked out One method of developing a pattern to make a hopper for entering a round pipe problems are the use of old principles in new ways, and the use of short cuts. If any difficulties are experienced in working these problems it will be of advantage to review the problems of the last two issues. The illustration (Fig. 1) shows the method of developing the pattern for a hopper entering a round pipe. A more technical statement of the problem would be “the development of a cone intersect- ing a cylinder;’”’ sometimes these technical statements are confusing if the terms used are not understood. In the previous problems, the base of the cone has always been placed at the bottom; in this one the base is at the top and the apex at the bottom; this makes it appear different, but the method of developing this problem is exactly the same. Another new point is that to save time and labor we have de- veloped only one quarter of the pattern, using only one-quarter of the bottom view. The steps taken for the develop- ment of the pattern are as follows: First, draw the front view, A, the exact size wanted. Betore we have gone very far we shall find that we cannot complete the front view without the aid of the end view, B. The joint line of the cone and cylinder is not absolutely necessary to develop the pattern, and the method of finding the joint line has been explained earlier in the series, but as this problem offers a splendid chance to review, it is deemed advisable to take advantage of the opportunity. Second, to complete the front view by drawing the joint line, we must draw the end view, B. Third, draw the top view, C, of the base of the cone on both front and end view, divide these half circles as usual and project the points to the base lines and then to the apex. Fourth, be very careful about numbering these points as a mistake will cause a lot of trouble. In the front view point number 1 is in the center of the base line and at the top of the half circle as indi- cated by the arrow line, but on the end view the same point number 1 is on the left hand side because we are looking at the problem from a different view point. Fifth, to get the joint line on the front view, A,: project lines across from end view, B, where the radial lines from the base to the apex cross the joint line be- tween cone and cylinder. On the front view, A, where these projected lines cross the same numbered lines going from the base to the apex, place a cross, then con- nect these crosses with a freehand curve and the front view will be complete. To develop the pattern will be easy enough for the students of this series who have completed the preceding problems. Briefly the steps are: First, draw the pattern arc, 1-5, getting correct length by stepping off the spaces from the top view, C. Second, project the radial lines from the point of intersection with the joint, line to the line apex-l, to get the true lengths as was done in all the pre- ceding problems. Third, swing these lines over to the pattern until they cross 935

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936 | Popular Science Monthly the same numbered lines, then make a cross, connect these crosses with a free- hand curve and the one-quarter pattern is complete. The illustration (Fig.2) shows the meth- od of developing the pattern for a bath Side A pattern for a bathtub is developed in a similar manner to a hopper and pipe tub. Notice that the tub is made up of five parts, bottom, two ends and two sides. The pattern for the bottom needs no development as the top view, A, gives us a true pattern. The patterns for both ends and one side must be developed in exactly the same manner as that described for Fig. 1, and will not be repeated here. Notice that it is one-half of a cone and developed in the same manner as for the hopper and pipe. The pattern for the end, C, is developed in the same manner, except that the base circle has been drawn downwards instead of upwards as was done on end view B. This method is offen used and was intro- duced here so that the students of this series might become familiar with it. The base circle is divided and the points projected to the base line, then to the apex in the usual manner. The points where the radial lines from base to apex cross the curved line of the tub are pro- jected over to line apex-1 and then swing across the pattern until they cross the same numbered lines in exactly the same manner as described for previous prob- lems. : The pattern for the side, D, is easily drawn. The correct width is obtained from D front view. The height is not correct on the front view because the top edge is leaning towards us. The correct height is obtained from the line, 1-X, ]t is the same height as the side, D, and hag the same angle of inclination or slant therefore, the line, 1-X, is the true height of the side, D. Set off the width from D and the height, 1-X, and the pattern for all parts is complete. Allowance must be made on these patterns for seams, and wiring as shown in previous issues. The illustration (Fig. 3) shows the de- velopment of patterns for an “egg tester.” A lighted candle is placed inside and the eggs are held against the egg- shaped hole. This must be done in a dark room. If the egg is clear and transparent it is fresh; if cloudy it is old. If it shows a dark spot, the process of incubation has started. The V-shaped hole at the bottom js to admit air so that the candle will burn brightly. The technical description of the prob- lem would be ‘‘development of pattern for a cylinder intersecting a truncated cone.” As stated before, these terms are often confusing to the non-technical reader, but advanatge should be taken of every opportunity to become familiar with them. The development of the pattern for the round pipe (cylinder) has been described so many times in various ways in this series that no further description is deemed necessary, neither is it shown in the drawing. The best explanation will be found in the December, 1917, issue, “Development of Pattern for Tee Joints.” The egg-shaped hole is drawn freehand. The development of the pattern for the cone gives us an opportunity to review the use of auxiliary points and to make use of a still different method of drawing the bottom view and base line circle. The steps taken are as follows: First, draw front view A and side view B. Second, complete the cone by continuing the side lines until they meet at the “apex.” Third, draw the bottom view, that is the circle on the base line. Notice that this is the first time that we have drawn the full circle on the base line. In previous issues it has been dropped down some distance from the front view to avoid confusion, but it is now time that we become acquainted with these different met! sixte thes dire lines lines cylil ape unt con cros han the hei the to 1 wid poil bef stra mal dist lay dra dist and

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——— methods. Fourth, divide the circle into sixteen equal parts. Project lines from these points direct to the base line, then direct to the apex; these are the radial lines. Fifth, from where these radial lines cross the joint line of the cone and cylinder, project lines straight across to 9 Developing a pattern for an egg tester which is a truncated cone and round pipe the line apex-1 to get the true lengths. Do the same with the V-shaped opening at the bottom. Sixth, draw the top and bottom pattern ares, N-M and 1-9, getting the correct length by transferring the spaces from the bottom view circle. Seventh, from the numbered spaces on the pattern arc, draw lines to the apex. Eighth, take the true length points on line apex-1 and swing them over the pattern until they cross the same numbered line coming up from the pattern arc, making crosses. Connect these crosses with a free- hand curve. Ninth, to get the pattern for the V-shaped opening, get the true height by projecting straight across to the line apex-1, then swing the line over to radial pattern line, 5. To get the true width we must make use of “auxiliary points,” as we have done once or twice before. On the front view project lines -straight to the bottom view circle (points marked X). With your dividers take the distance on the circle from point 4-X and lay off on the pattern arc as shown in the drawing. Do the same for the other distance, 6-X, connect the three points and the one-half pattern will be complete. | Popular Science Monthly 937 The illustration (Fig. 4) shows the de- velopment of patternsfor a“‘Dust collector Intake.” The technical description of this problem is ‘‘Rectangular four-sided Prism Intersecting a Truncated Cone off Center.” The steps in the development of the pattern are as follows: First, draw front view, A; the joint line cannot be drawn until the points are projected across from the side view, B. In this problem the joint line is absolutely necessary and is obtained by drawing the bottom circle on both front A and side B views (as only one-quarter pattern is needed, only one-quarter circle is drawn). Second, space and number each bottom view quarter circle as in the preceding problems. Be very careful to number these correctly. Notice that 1 is at the right on front view A, but in the side view B it is in the exact center. Third, from these numbered points draw lines straight up to the base line, then straight to the apex. Fourth, on side view B where the lines to the apex cross the end view of the rectangular pipe make marks as in the drawing and draw lines across to the front view, A. Where they intersect the same numbered lines coming up from the bottom make a cross. It will be noticed that if we use only the regular numbered lines coming up from the bot- A dust intake collector or rectangular four- sided prism intersecting a truncated cone tom view quarter circle we shall not have enough points to definitely locate the joint line on front view A, so we must again make use of the “auxiliary lines.”

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938 | Popular Science Monthly On the side view B draw a line from the apex through the lower left-hand corner of the rectangular pipe until it strikes the base line, then drop it straight down to the bottom view quarter circle, mark X. Do the same with the upper right- hand corner and the lower right-hand corner, marking them respectively Y and Z. Now transfer with the dividers from the side view B bottom quarter circle to the front view A quarter circle the points X, Y, Z, getting the correct distance from points 2 and 3. From X, Y, and Z on the front view A draw lines straight up to the base line, then to the apex. Now draw the lines over from the side view to the front and make crosses just as you did with the regular numbered lines. Con- nect the crosses and you will have the complete joint line. The dotted part of the joint line is drawn dotted because it is invisible, as it is back of the pipe. Now that we have the joint line we can proceed with the development of the cone pattern. It is only necessary to develop one-quarter because the important part is the hole and by marking off the pattern four times we can get the full pattern. This also saves metal and bulkiness of patterns. In the usual manner draw the top and bottom pattern arcs 1-5 and M-N, getting the correct length as usual by getting the spaces from the numbered points on the bottom view circle. Be sure and include the ‘‘auxiliary points.”” Then from the points where the lines we used to get the joint line cross the line apex-P, draw circles around to the pattern until they cross the same numbered or lettered lines. ‘Where they intersect make crosses, then connect these with curves and the one- quarter pattern will be complete. Now we have to get the pattern for the rectangular pipe. Notice that we already have the correct pattern for the two long sides of the pipe on thefront view A. The front side is marked C and the back is marked D. Transfer the size and shape of C to the pattern, using the line H-K as a base line, getting the correct lengths from the end view of the pipe on view B. We must next get the pattern for the top of the pipe. This is done by the use of the top view G. Project two lines up- wards from the rectangular pipe to points L and R on the top view, then draw the arc L-R. From the front view 4 get the correct length of the pipe and set it off on the top view G. This will give us the pattern for the top of the pipe F Place this with C on the pipe pattern, next transfer the side D from the front view. To get the pattern F for the bot- tom of the rectangular pipe: On the side view B draw a line from the F to the line apex-5. Then up to point S on the top view. Then draw the circle S-T as indj- cated and you will have the pattern for the bottom F. Place this next to D and the pipe pattern is complete. (To be continued) Making a Lattice Trellis for Roses and Vines GOOD trellis for roses and vines may be made.as follows: Procure ag many 1\%-in. by 14-in. strips of wood as there are feet to the width and of the right length, and also as many for every foot ‘Hi \) f HH al The strips of wood are interlaced in the construction of this trellis for roses in length and proceed as follows. First lay out marks 12 in. apart on the strip to be used as a base, then tack the pieces that are to be used upright to these, each alter- nating piece on the other side from that nailed last, then interlace the cross pieces in these lengths as in weaving. The trellis will then have the appearance as shown at A. This lacing of the strips makes the trellis quite substantial.— Louis M. WAHRER. ciall Alur shap adar like TI

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How to Make an Efficient and In- expensive Fireless Cooker HE materials needed are a box, or some other outside container, some good insulating material, B, a kettle for holding the food, a container for the lining of the nest in which the kettle is to be placed, and a Popular Science Monthly 939 or the lining for the nest in which it is to be put, should be cylindrical in shape and deep enough to hold the cooking kettle. It should fit as snugly as possible to the cooking vessel, but at the same time should allow the latter to be slipped in and out freely. If the cylinder is too large the air space between it and the kettle will tend to cool cushion or pad of in- sulating material for the cover on top of the kettle, and a cover, G. For the outside con- tainer a tightly built wooden box as illustra- ted is the most satis- factory. The box should have a hinged cover, and at the front a hook and staple to hold the cover down. A window fastener answers the purpose well. The size of the box should be large enough to allow for about 4 in. of pack- ing material all around the nest in which the kettle is set. The kettles used for cooking should be dur- able and free from seams or crevices, which are hard to clean. They should have vertical sides and the covers should be as flat as possible and provided with a deep rim fitting well down into the kettle to retain the steam. The size of the kettle should be determined by the quantity of food to be cooked. Small amounts of food cannot be cooked satisfactorily in large kettles, and it is therefore an ad- vantage to have a cooker with compart- ments of two or more different sizes. Kettles holding about 6 quarts are of convenient size for general use. Tinned iron kettles should not be used in a fire- less cooker, for, although cheap, they are apt to rust from the confined moisture. Enameled kettles are satisfactory, espe- cially if the covers are of the same material. Aluminum vessels may be purchased in Shapes which make them especially well adapted for use in fireless cookers and, like enameled ware, they do not rust. The container for the cooking vessel, the food. For making this container a gal- vanized iron or other metal bucket, B, may be used or, better still, a tinsmith can make a lining of galvanized iron or zinc which can bes provided with a rim, A, shown on_ following, page, to cover the pack- ing material. For the packing and insulating material a variety of substances may be used. Asbestos and mineral wool are doubtless the best, and have the additional ad- vantage that they do not burn. Ground cork or the packing from The outside container may be = laga es, hay, ex- any box of a convenient size celsior, Spanish moss, wool, and crumpled pa- per may also be used satisfactorily. Of the inexpensive materials that can be ob- tained easily, crumpled paper is probably the most satisfactory, since it is clean and odorless, and, if properly packed, will hold the heat better than many of the others. To pack the container with paper, crush single sheets. of newspaper in the hands and pack a layer at least 4 in. deep over the bot- tom of the outside of the container, tamping it in or pounding it with a heavy club. Stand the container for the cooking vessel, or the lining for the nest, in the center of this layer and pack in % Y AY y 4 Yj Yj y Yj ie 7) Ssssi SSS SULLA ML ULI IE Section through cook- er showing insulation

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940 = - more papers about it as solidly as possible. Whatever packing material is used, it should come to the top of the container for the kettle, and the box should lack about 4 in. of being full. A cushion or pad must be provided to fit completely the space be- The cover with a deep rim and the con- tainer for the cooking vessel within the box tween the top of the packing and the cover of the box after the kettles are put in place. This should be made of heavy goods, such as denim and stuffed with cotton, crumpled paper or excelsior. Hay may be used, but it is somewhat odorous. The classes of food best adapted to the cooker are cereals, soups, meats, vege- tables, dried fruits, steamed breads and puddings. When different foods are cooked together in the fireless cooker they must be such as to require the same amount of cooking, since the cooker can- not be opened to take the food out without allowing a large amount of heat to escape, It would not do to put foods which need about 114 hours to cook in a cooker with, say, a piece of meat that requires several hours’ cooking. A Driver for Holding a Screw While Turning It AKE a round piece of wood, some- thing like a lead pencil, of the re- quired length, run a fine saw lengthwise through the end of it; then take a discarded clock spring, cut two pieces of equal lengths and insert them in the saw with the curves out. Wind it se- curely, pinch the ends together, insert them in the slot of a screw and you can hold it at any angle. If a watch spring y is used and the ends Spring on end made keen enough the ae eel device can be used to drive very small screws.—E. L. GRIFFITH. Popular Science Monthly Extension Holder for Hauling Stock on Express Wagon b iky holder is made of two bars, each 9 ft. long and 34 in. in diameter They are bent at right angles on one end to make an upright 16 in. high. Thege pieces are joined together with another piece of the same stock welded in as at B. The length of this piece will be regulated by the width of the express wagon box on the inside. , The bars are held in place inside of the wagon box with four pieces of metal shaped as shown at C and made from stock 1 in. wide and \% in. thick. These are bolted to the upper surface of the bottom of the wagon box. Extension rods on a wagon box to hold the pipe ends and keep them from lashing about The upper ends of these rods are thread- ed for almost their entire length and fitted loosely with two nuts. A crossbar, D, made of stock 2 in. wide and \ in. thick is drilled to fit on the rod ends be- tween the nuts, A. In hauling long rods, pipe or lumber the holder is slipped in place in the clips, C, and the material loaded on it. The cross- bar, D, is then put on and the nuts ad- justed to hold the load. This prevents the long ends of the material extending from the rear of the box from lashing about and makes it possible for the load to be placed against the front end of the wagon box, where it will not extend over and strike the horse. This device is very serviceable.—JAMES E. NOBLE. len siz ler

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AA CC = FIG! MAN B : hy el PLANKS, eee | Fina. y i PLA ze N a Mee 4 Lp oo, FI nay iD . WATER L AS LRG Ryne < — Ay a Sepak T : \ Pejy +57 Ns MB WK 1— Poise &, Z . ein A L0G og POA ERM Qh PiGe hs _~ = p VG E OES Sac a—a ors ee rer ee ee = Ze GE ZZ SBN ee a : 0" ot Oe a ae A Rope Suspension Bridge for a Garden USPENSION bridges present a very artistic structure for spanning small streams or a brook on the grounds or in a park. The illustration gives the details of such a bridge and tables of proportions for construction of the different lengths. The concrete posts which hold the upper cord of the bridge are built and reinforced as shown in Fig. 1. The suspension cable is secured to a drive anchor, expanding anchor or dead man and then run across the ravine and se- cured on the opposite side in the same manner. Both suspension cables should be the same length and have the same amount of slack or sag. The lower cord is drawn as taut as possible and then hung perfectly level by the supporting vertical cables, which should be spaced about 1 ft. apart. When all vertical cables are se- cured to both the upper and lower cords the latter is drawn up again and secured at each end. Planks are laid across the lower cord and held in place by driving large staples over the rope and into the bottom of the plank. The tables should be studied closely. Table 2 gives the size of the post, length above and below ground and size of spread footing, while Table 3 gives the size of the ropes to use for the various lengths of the span. In the last column

of this table is given the size of the bottom cord of round iron bar, which is used in place of manila rope, and in Table 4 is given the number and size of the bars necessary to reinforce the columns shown or mentioned in Table 2. a A————_fo]

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Across section of the completed bridge and the detail of the anchor post and its base The illustration, Fig. 2, gives a cross- section of the completed bridge, while Fig. 3 shows a little more detail of the

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942 Popular Science Monthly © ; anchor post. Of course the builder can exercise his own ingenuity in designing the posts and in the method of connecting the upper and lower cords, but two half- hitches of the vertical cables around both the upper and lower cords will answer the purpose. Care must be taken to see that

A B C D E 6 ft. § ft. 4 ft. 14 in. Tby Tn. 8 “ 6 “ 4 “ce 14 “ec 8 “es 8 “se 10 “cc 7 ee 4% “ 18 “ec 8 “ 8 “ 15 “ 8 “ce 5 “ee 90 “ee 10 “c 10 “< 20 “se 10 “é 6 “e 4 “ce 12 “ 12 “e A AA BB CC Hemp} CC Iron 6 ft.| 5% in. dia.| 54 im. dia.|5gin. dia.|% in. dia. 8 “ce 34 “ec “ 5% ee “ 5 B “ ee 1 6 “cc “ 10 “ 1 “ “ec % “e “ 34 “c “ % “e “ 15 “cc V4 “ec “ce 34 “ “ee 1 “ee “ce 3% “ec “ 20 “ 1% “ “ec 34 6 “ 1 “ec “ce 34 “ “ce SizE SizE NUMBER or Post oF Rops_ | or Rops Tby Vin. by 9 ft. 3% in. dia. 4 8 “ce 8 “ee “e 10% “ce % “cc “ce 4 8 “ 8 “e “ce 11% “ee % T7 “ 6 10 “ 10 “ “é 14 “ee 1 ce ae 8 12 “ 12 “ec ce 16 “é % os “é 8

the cables are kept free from chafing and all ropes and cables should be well soaked in good hot pitch before the work is finished or decay will ruin the bridge in a short time.—GEORGE M. PETERSEN.

Starting a Very Small Screw with Adhesive Tape EING without the necessary tweezers to handle a very small screw I took a match-stick and put a piece of ad- hesive tape on it as shown, then wrapped it with another piece to hold it to the stick. The screw- head adhered to the tape well enough to permit its being placed in position Adhesive tape and given a couple match to start screws of turns before it was necessary to use a screwdriver.—JAMES M KANE.

A Scaffold for Holding in Place with a Pole HIS device I saw in use by some country plasterers who were re. plastering the very high end of a farm house. Each one was made of two pieces of 3 by 4-in. stock, about 3 ft. long for the upper part, and 4 ft. for the other side of the angle. To make it, nail the two pieces together to form an angle. Then prepare two pieces of 1-in. white pine board, and nail.____ | one end to the ~~; outer end of the horizontal’ arm, and the other end to the bot- tom of the ver- tical part. Also fasten the two pieces at the top Portable scaffold of the angle, as brackets for work shown in the il- on house exteriors lustration. The long pole is used to push the bracket up against the side of the house into position, at any desired height, and according to the length of the pole, The double braces keep the scaffold from turning side-ways on the pole when placed on the side of the house. Such a scaffold will hold almost any weight, for the more the weight the tighter it will hold, though the pole should have firm footing, not too soft, but not hard enough to cause slipping. Two of the brackets will do ordinary jobs, but as many brackets may be used as may be necessary, of course. This scaffolding has many features to commend it to work- men.—A. A. KELLY.

Holding Photographic Plates from Tray Bottom HE developing of plates in a flat tray in a darkroom is often a very bother- some task, because the plates stick to the bottom of the tray when one wishes to remove them for examination and at the end of the development period. An excel- lent plan to avoid this trouble is to stretch a rubber band loosely over and round each end of the tray through the developer and then lay the plates on the sagging rubber bands, which will prevent the plates from sticking and improve the general results.

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A Convenient Summer Cottage By C. M. Tomlinson ee AR 8 ft. sereened-in porch at each end makes the total length 40 ft. The low cost is made possible by choosing the dimensions so that stock sizes and lengths of lumber, doors, sashes, etc., may be used. With a little care in buying there is little waste, and in many cases no cut- ting is required. To secure the maximum of accommoda- tions, every device known to the modern builder is used. The floor is divided near the middle by a partition, making a living room at one end and a dining-room and wash room at the other. A fireplace on one side of the living room assures com- fort on cold mornings, chilly days, and during the cool weather of late fall or early spring. Recesses 12 in. deep in the partition provide space for three swinging beds which are screened off by partitions during the day. Occupants of each of the beds in the living room secure privacy by dropping curtains from the ceiling; a passage way through the center of the room is left at all times, and one-half of the living room may be occupied by those Ts cottage proper is 18 by 24 ft.; an 943 sitting up late when the other half is used as a bedroom. The spaces.in the parti- tion not required for the beds are utilized for closets. The doors of the porches fold back so that by opening them wide the area of the living room and dining-room are really made to include the additional space. The wash and dressing room has an en- trance from the outside so that bathers need not track through the rest of the building to reach it. Bookcases are built into the walls be- tween windows, and the walls of the wash room and kitchen likewise utilized for the appropriate built-in furnishings. Trunks may be placed in the corners behind the doors and screened off. The cottage is so planned that it may be built in sections, the structure making a harmonious whole at each stage. If de- sired the wash and dressing room may be made a little larger and used for a maid’s or chauffeur’s room. A second story may be added for about $200. By making the greatest possible use of the cottage, the following accommoda-

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Popular Science Monthly

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The floor is divided near the center with a partition, making a living room at one end and a dining-room and wash room at the other and a fireplace in one side of the living room tions are provided by the ingenious ar- rangement: By day: Living room 11 by 18 ft., with fireplace, or with front doors open to include porch, 18 by 19 ft. Dining-room 10 by 11 ft., or with doors open to include porch, 10 by 19 ft. Kitchen 7 by 11 ft., with kitchen porch 6 by 7 ft. Wash and dressing room 4 by 7ft. Front porch 8 by 18 ft. Rear porch 8 by 10 ft. By night: A front porch 8 by 18 ft., which by the use of screens may be turned into a sleeping porch. Rear porch almost as large capable of same use. Two front bedrooms each 7 by 11 ft. One rear bed- room 10 by 11 ft. If the sleeping porches are utilized and a cot placed in each bed- room, sleeping accommodations for a dozen people may be provided.

How to Make an Automobile Spring Leaf-Separator HE body springs of an automobile should be periodically lubricated. This will result in greater comfort to the occupants as well as in quieter riding. A common practice on the part of the average driver is to separate the leaves of the springs with the aid of a hammer and chisel or a screw-driver. Procedure such as this, however, is extremely detri- mental to the well-being of the springs, the constant hammering causing unneces- sary strain on the leaves. The accompanying sketches illustrate the construction of a simple appliance which was built from discarded automo. bile parts such as may be found in the junk pile of any average garage repair shop. It consists essentially of a rod, A, to both ends of which are riveted levers, B, (discarded brake levers). The pointed plugs, C, are riveted into the upper end of one lever, while screw D passes through the upper end of the other lever. A third lever, -F, placed between the levers, B, is bored out at its hub to permit its sliding smoothly over the shaft, A. In addition its upper end is provided with a plug, C, similar to that placed in the other lever. The plug in the lever, F, however, is bored out at one end to receive the pressure from the screw, D. The operation of the appliance is ex-

WEDGE Se yP So i= WEDGE } PRING rivereD | |] LEAVES | B fF B = A ad LA YW (G2 & RIVETED PIN RUNNING FIT 4% RVETED PIN Levers mounted on a bar carrying cone points for separating the leaves of a spring tremely simple. Turning the screw, D, forces the plugs, C, towards one another; consequently when they are placed be tween two leaves of the spring, a few turns of the screw will readily separate them.—ADOLPH KLEIN.

Self: rapit crete pan}

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Self-Measuring Wheelbarrow for Concrete Aggregates SELF-MEASURING wheelbarrow designed to promote convenience, rapidity and accuracy in handling con- crete aggregate, is shown in the accom- panying sketch. It consists of an ordinary PIN dh i! VERTICAL dt STOP BAaR—~__ a t ' TRANSVERSE at pe tyme WOOD GAGE Ps t Measuring box on a wheelbarrow for ob- taining the proper amounts of concrete steel body wheelbarrow pan with a trans- verse wood gage of the same shape as the inside of the pan. This gage is moved up and down in the pan, according to the amount of concrete to be carried, the latter being measured between the gage- board and the rear end of the pan. The gage-board may be set at any desired position by means of a transverse bar across the top of the pan. The bar is held in place by two pins inserted through any one of a series of small holes along the sides of the pan at the top. The gage- board is held against the transverse bar by a vertical wooden piece nailed to a web fitted to the gage-board at right angles to it at the open end. When the concrete is to be dumped, the gage-board is re- moved. Applying Grease to Working Gloves to Make Them Wear FRIEND of ‘mine who does heavy work of various kinds which requires gloves, and heavy leather gloves at that, advises me that gloves can be made to wear almost like iron by applying axle grease sparingly and being very careful not to get it on the cloth stitching, as the axle grease may disintegrate it somewhat. Popular Science Monthly 945 Making a Photographic Timer out of an Ordinary Watch SIMPLE adaptation of an ordinary watch to use as a timer of value in long photographic exposures by photo- engravers and printers, or for use in timing action of developer, can be made by painting a narrow line on the under side of the edge of the watch crystal. Then, by revolving the crystal till the mark coincides with the minute hand, it is easy to register the exact time that ex- posure began.—GEORGE PARKE. Joining the Ends of Carpet Rags Without Sewing fa old backwoodsman used _ this method of joining carpet rags end to end, without sewing the strips together. He mounted a strong knife blade, pre- viously shaped like a crochet needle, as shown in Fig. 1, on the bench he used for a seat. The point and upper edges of the knife were sharpened as shown in Fig. 2. Taking the ends of two strips, he pressed them down over the blade, Fig. 3, until they were as shown in Fig. 4. One end was looped under the eye of the needle, Fig. 5, and while holding the ends A and an g2 Fig.4 Fig.5 Knife blade arrangement for fastening the ends of carpet rags without stitching B, Fig. 6, they were drawn upward. The resultant knot, Fig. 7, can be shaped as in Fig. 8 and drawn tightly as in Fig. 9. Other pieces are attached in the same manner to make a continuous line for the weaving.—JAMES M. KANE.

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946 An Inexpensive and Effective Water Cooler N the usual gas-engine installation the water is circulated through a large tank where it is cooled by radiation. Ordi- narily this process answers every purpose, . aunial : = 7 Ss = = I SSSS€Aa@eX>= TB Ss E2geea Ba Be = 2 0 —— | | Ezz _ Sy \ i ee AE —_— | = —S | a ih—_— | Feed eS A - | || = 0 ee Hot Ul = EA AM: ‘i ~ Sa Cold 1x8" Per forations Feed pan ) Numerous boards arranged in a rack to spread the water for cooling it in the air but in the case of small ice plants, now becoming rather common, a much greater cooling effect is desired. The accompany- ing illustration showsa simple and yet very effective cooler in which the cooling principle utilized is that of evaporation. The apparatus is easy to construct and the cost is low, as it is made almost entirely of wood. Briefly stated, the method consists in emptying the heated water into a long, narrow galvanized-iron pan, perforated along each side with a series of small holes. The water drips in fine streams through these and falls on a board inclined toward one side, which becomes thoroughly and uniformly wet on its upper side. The water then trickles off the lower edge onto a similar board inclined in the opposite direction. The wetting action is here repeated and the water falls onto a third board, and so on for twenty or thirty drops, according to the cooling capacity desired. It is finally caught by another galvanized iron pan at the bottom, from which it is pumped for use again. Aside from its cheapness and ease of Popular Science Monthly construction, the wood has a distinct advantage over metal in that the water spreads out in a uniform layer, whereas on metal the tendency of the water js to trickle down in small irregular streams The cross-sectional diagram clearly shows the relation of the sloping boards and the two pans, while an idea of the general appearance will be gained from the perspective view. When used on the shady side of a building, in a region where the humidity is low, the evaporation jg rapid and the cooling effect really re markable.—JOHN D. ADAMS. Renewing a Worn Artist’s Brush by Repointing It HE points of sable or camel’s-hair brushes such as are used by artists rapidly wear away, thus rendering them practically worthless. An apparently worthless brush may be restored by dipping the bristles in glue, pointing it as well as possible at the time. When thoroughly hardened the brush is repointed on a sharpening stone the same as if it were a steel point. It can be done even more rapidly by holding against a slowly revolving emery wheel. The glue is then dissolved by immersing in hot water.—L. B. ROBBINS. A Spring Lock for the Cover of a Garbage Can HIS lock is for attaching to an ordinary garbage can, built like a pail having a bail. The spring catch, as illustrated, is riveted to the can cover, SPRING {BRASS CATCH 62 K r jg RIVETS / LID ra put _iil “i | | f || Vi | | CAN | Spring catch on a garbage can cover to hold it in place with bail in upright position the upper part snapping under the bail when it is in an upright position for car- rying.—P. P. AVERY. la wit iW]

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A Cleat for Holding Temporary Electric Wires HE accompany illustration shows a simple means for holding temporary wiring in place. The cleat is nothing ®@@ Lt Glass push pins used as temporary cleats for electric light and telephone wires SocseoK more than the handy little glass push pin that can be purchased at any stationery store. It is very easy to attach, does not mar the surface of the wall and, being glass, is of course an insulator. The pin is first forced into the wall and then the double conductor cord is slipped over the head.-EDWARD R. CULLEN. An Electrically Driven Toy Tank That Goes ‘‘over the Top’’ HIS caterpillar tank will crawl along the ground, go “over the top” of miniature trenches, plunge through wire entanglements, and push aside or climb anything that is in its path. It is a small model of the latest machines that the ig Army has been using so success- ully. Two side pieces cut from 14-in. pine wood in the shape of a diamond 12 in. long, constitute the frame. At each cor- ner of the frame a roller is placed. These should be 6 in. long and 2 in. in diameter. A small nail driven through the frame Electrician 7-And Wireless Operator Amateur - corner and into the center of the end of the roller makes a shaft that is good enough for the purpose. Now for the construction of the interior. Between the bottom edge of the frame- pieces a shelf should -be nailed and upon this fastened the batteries and an electric motor, which will furnish the power. These should be secured with screws so that in case the tank tips over they will not be jarred out of place. Belt the pulley of the motor to the nearest roller and wire the batteries to the motor. Over the four rollers a canvas or leather belt is laced snugly. To keep from slip- ping this belt should have several narrow wood cleats nailed upon it. A small door in the frame makes a convenient place to get to the motor in order to turn on the power, etc. It is evident that when the current turns the motor that the rollers will revolve, and, as the belt grips the ground securely because of the cleats it A toy tank made of wood and inclosing a motor and batteries for the power plant carries, the. caterpillar tank will crawl slowly along. The motor is of the small, toy size; from 4 to 6 in. high being plenty powerful enough.—F. E. BRIMMER. 947

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948 Popular Science Monthly Durable Terminals for Electrical Conductor Cords HE terminals of flexible conductor cords often become frayed with use, a condition which results in poor con- nections and short circuits. A good terminal is made as follows: Peel back the insulation on the cord until a clean surface is obtained; then cut it off squarely and bend the end into a symmet- rical loop. Dip the loop first into solder- ing flux and then into molten solder, holding it until the solder “takes.” This forms a solid terminal which can be screwed down tight without injury and will prove satisfactory.—THos. A. REYNOLDS, Shocking Device That Works on - the Commercial Current N electrical shocking device which gives an even, soothing effect to the nerves is preferable to those which pro- duce slow, intermittent discharges. An apparatus for producing the soothing current is quite easily made. The source of current is an 110 volt A.C. which is reduced by resistance. The main source of resistance is the weak solution of salt and water in the two upright glass tubes. The electric light bulb is of 25 watt power and is used to judge the strength of the current and also serves to reduce it. The current can be regulated by means of the two hat-pins which Resistance in two tubes to reduce alter- nating current for a shocking machine project through the stoppers of the tubes. One set of binding posts is for the main circuit, the other is used for the trans- mission of the current into the body. A set of handles made from the carbons of old dry cells are used for hand-grips. To regulate the shocker, see that the switch, shown in the center of the illus- tration, is turned off. Then short-circuit the hand-grips and turn on the switch Push down the hat-pins in the tubes until the wires in the bulb are reddened. Note the amount of water that is between the connection points of each tube. Add the two amounts and increase the distance between them about 8 in. A very low current should be flowing through the apparatus and it is now quite safe to grip the handles. The current can now be varied to suit.—JOHN C. JAcK. Locating and Repairing Short- ’ Circuited Armature Coils i locate a short-circuited armature coil, pass a current from a battery of dry cells, or a storage battery, through the armature, using the brushes of the machine for terminals. Using a low- reading voltmeter, touch its lead wires to one pair after another of the adjacent commutator segmenis. A zero deflection of the voltmeter needle indicates a short- circuited armature coil. It will be seen, at periodic intervals in passing around the commutator, that the meter deflection reverses, and that just preceding this transition point the value is less than normal deflection. This merely indicates the passage from one pole to another on the winding. Thus, for instance, on a four-pole armature, there will occur four such reversals. Switching of the voltmeter leads will cause the meter to register in the right direction. If a “short” is found, clean out the spaces between commutator segments, to be sure that no mental dust is responsible for the trouble. If this trial fails, care- fully lift out the coil connected to the bars to which the short-circuit was traced, and repair any insulation breaks. If a winding is broken, the break may be located by connecting a battery through an ammeter to two metal strips, held apart by a piece of wood, at such a distance that they will touch adjacent bars on the commutator. Holding this device against the commutator surfaces turn the armature slowly by hand. A reduced or zero deflection of the meter indicates a broken or open-circuited winding. The only thing to do in this case, is to lift out the damaged coil, solder the ends together, re-insulate the break, and place the wire back in its proper slots on the armature.—PETER J. M. CLUTE. dec rer

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Electrical Devices and How They Work VI.—Electrical metering instruments By Peter J. M. Clute, B. E. only through certain effects which it produces. These effects may be mostly classified under chemical, thermal, magnetic, and static effects. Chemical effect is manifested by the decomposition of a solution when a cur- rent of electricity passes through it. Thermal effect is produced by the pas- A - LCollected gases Prreny throush, is manifested to us Covering to prevent evaporation ; Rea Aas Acidulated water electrolyte Platinum. snu0- ees electrodes 2 MMM GMM Agasvoltameter consisting of two platinum electrodes immersed in acidulated water sage of an electric current through a con- ductor of appreciable resistance. Magnetic effect results from an electric current in a conductor when brought into a magnetic field, the field being produced by a magnetic or other electric currents. Static effect is the attraction or re- pulsion existing between highly electrified bodies. These effects all occur in perfect ac- cordance with definitely fixed natural laws, and as a consequence they have been utilized in the design of various instru- ments for the measurement of electrical qualities. Electrolytic meters, depending on the chemical effect of the electric current, do not indicate directly in amperes the cur- rent flowing, but are used to determine the quantity of current which passes in a definite period of time. Thus, they should 949 be termed coulomb, or ampere-hour, meters. In Fig. 1 is shown the gas volta- meter or electrolytic meter. The gas voltameter consists of two platinum electrodes. immersed in acidulated water, so arranged that all the evolved gas would be collected in a graduated cylinder. It can thus be demonstrated that the amount of gas is entirely independent of any consideration by the quantity of cur- rent flowing. By using solutions of different metals for electrolyte, it can be shown that the weight of metal deposited on the positive electrode is always pro- portional to the amount of current in the circuit. The commercial electrolytic instrument depends on the principle that current passing through a volume of water de- composes it into its constituent gases, hydrogen and oxygen. This decomposi- tion is directly in proportion to the cur- rent passing, one ampere-hour decompos- ing .338 gms. of water. The current flows through a volume of water contained in a properly graduated tube, the change in volume of water in a given time, indi- cated by the difference in levels, showing the amount of current which has passed. The commercial use of electrolytic meters is quite limited, and in most cases they have been superseded by direct- reading electro-magnetic type meters. The thermal effect of electric current is utilized in some instruments to measure the current passing, by means of the ex- pansion of a wire. The heating of a wire is proportional to the square of the cur- rent and the resistance of the wire, when a current is passed through it. Hot-wire instruments are used to meas- ure current or differences in potential by the heating effect of the current. Refer- ring to Fig. 2, a long wire, of high re- sistance, non-oxidizable metal, has one end fastened to a plate, passes over 2 pulley and back to the plate. A spring attached to the plate keeps the wire stretched taut. When a current is passed through the wire, it heats and expands,

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950 Popular Science Monthly the increase in length causing the pulley to rotate, carrying the arm with it. This arm movement causes the silk fiber to rotate the shaft, which carries the needle. Hot-wire meters deflect in the same direction for currents in either direction and are equally accurate on direct and alternating current. They are not af- fected by stray magnetism and have the advantage that they can be calibrated on direct for use on alternating current. This type of instrument is not generally employed in practical work, but is valua- Wovable needle of meter ~~ “Pulley . ~ Shaft Non-oxidizable “nae STZ SX 8 j1L— Arm Spring to keep plate under press ster Fig.2 **. Shoft with : pulley Hot-wire meters deflect in the same di- rection for currents in either direction ble for measuring currents of high fre- quency, such as are used in wireless telegraphy. The simplest form of meter employing the electromagnetic effect is the gal- vanometer, an instrument for detecting small currents. In Fig. 3 is a so-called tangent galvanometer, the operating prin- ciple of which is as follows: If a coil of wire is placed in the plane of the magnetic meridian (N and S line), and a magnetic needle is suspended at its center, a current passing through the coil will deflect the needle away from the magnetic meridian by an angle whose tangent is proportional to the current strength. The D’Arsonval galvanometer is a modification of the tangent galvanometer, with reversed positions of moving and fixed elements. In this instrument, there is a small solenoid oscillating under the directive force of a permanent magnet, instead of a suspended magnet movin under the directive force of a coil. Cyp. rent which is lead to the coil through its suspension causes it to rotate about its axis, with a ten- dency to place itself at right angles to the lines of force. A pointer may qummdemmm be fastened to & the coil to show the deflections, Term. of : se Coil y) oramirror may ms Leveling be used, from fg3 which a re- The simplest form of : rm of a flected light Tay tangent galvanometer formsthe point- er. In most forms of this instrument (see Fig. 4) a soft iron core is supported be- tween the magnet poles from the rear, leaving a space between core and magnet, in which the coil swings. This tends to increase the magnetic field in which the coil rotates, giving a more sensitive deflection. Galvanometers are generally used to indicate the presence and direction of electric currents rather than to ascertain their intensity. The D’Arsonval princi- ple, however, can be applied to portable meters for the direct measurement of voltage and amperage. When used to measure po- tential or E. M. F. they are called voltme- ters, and are graduated to read in volts; and when measur- ing current, they are called am- meters, and read the cur- rent in am- peres. In Fig. 5 is shown the D’Arsonval principle as applied to in- struments of this sort. In fundamental principles, ammeters and voltmeters are alike, inasmuch as the deflecting torque of the instrument Gi-mr ————— To term. Mirror... Soft iron core Suspended Movable coit A soft iron core sup- ported between per- manent magnetic poles

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proportional to the strength of the mag- netic field multiplied by the current flowing in the movable coil. An ammeter, since it measures the current flowing in the conductor, must be placed in series in the circuit and hence its coil should have as low resistance as possible. On the ther hand, . voltmeter, SX, Printer inasmuch as it measures the potential difference be- tween two wires, should be placed across these wires, and, therefore, should have a high _=—ire- a sistance SO as Fig.5 to take but a small current. Since the voltmeter’s resistance is fixed, the cur- rent through the meter will be propor- tional to the E.M.F. in volts, so that, like an ammeter, a voltmeter really oper- ates in obedience to current variations. In the ammeter, the movable coil is composed of a few turns of larger wire than is used in the voltmeter. When de- signed for small capacity, the total cur- rent to be measured may be passed directly through the coil. For heavy currents, in excess of the ampere capacity of the wire or in excess of full-scale meter deflection, a portion of the current is shunted through a low resistance circuit called a shunt, which is paralleled in the circuit of the movable element. Thus, by using a suitable shunt, a current of any magnitude may be measured. In the voltmeter, the moving element consists of many turns of fine wire in ‘series with which there is a resistance. This resistance is such that, when maxi- mum voltage is applied, the current through the movable coil is limited to the amount necessary to give full scale de- flection. Electrometers are instruments depend- ing upon the mutual attraction between opposite electrostatic charges. If a source of E.M.F. is connected to two metallic plates, they will take charges in propor- Torsional and, / conducting spring Counter balance wound on -” aluminum frame Movable element in the D’Arsonval type Popular Science Monthly 951 tion to their potential difference, and a certain electrostatic attraction results. If one of the plates is permitted to move, the electrostatic capacity of the system increases, thus increasing the amount of the charges and the force of attraction. This principle is employed in the con- struction of electrostatic voltmeters, adapted for the measurement of high voltages. This meter is easily insulated, of simple construction, requires no inter- nal resistance wire, it consumes no cur- rent on D.C. and practically none on A.C., its deflections are independent of the frequency, wave form, and stray magnetic fields, and it indicates equally well on direct and alternating current. The electrostatic voltmeter, shown in Fig. 6, consists primarily of fixed and movable metallic vanes of relatively large surface, generally plane, but sometimes curved. The two terminals are ton- nected, one to the fixed part and the other to the movable part, which has a pointer attached to give the deflections on a graduated scale. The type of electro- static voltmeter shown is designed for potentials of 1,500 to 10,000 volts. In addition to the above standard types of electrical meters, there is still quite a number of other instruments designed for special uses. These include: The frequency meter, or indicator, used to determine the frequency or num- ber of com- plete cycles per second of an alternat- ing current. The watt- meterused for measuring directly in watts the power expen- ded in a cir- f Pointer cuit. Watt- = meters are of Movable vanes Term. either the in- Fig. 6 dicating or re- The voltmeter consists of cording type. fixed and movable vanes Ohmmeters used to give directly the value, in ohms, of a resistance that is being measured. The dynamometer, a moving coil meter, used for measuring currents,

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se a a 952 Popular Science Monthly E.M.F.’s, and power on both D.C. and A.C. circuits. The permeability bridge, an apparatus designed for the determination of the magnetic densities of iron corresponding to given magnetizing forces. The hysteresis meter used for measur- ing the hysteresis in sheet iron and steel. The Wheatstone, or slide-wire, bridge used for the accurate determination oi re- sistance. The above discussion includes the principal types of meters and instruments used in the testing of electrical apparatus. While there are other meters on the market, it will generally be found that they are simply modifications of one or the other of the above typical meters, or are designed for very special or limited use. (To be continued) A Combined Electric Night-Bell and Flash-Light N rigging up a bell for an invalid it was decided to add an extra wire and Splice have a flash-light = as well as a bell. 3 The bell and light Soldered are independent of each other, al- though one of the Sprin bell wires is also — used for the light and the same bat- teries work them A Thimble Used as a Ferrule on a Tool Handle Fy old thimble makes an excellent ferrule for a _ small Screwdriver handle or a similar tool. A notch is filed in the thimble end to admit the rectangular shank of the tool like a flat file. Round shanks may be fitted into a drilled hole or the thimble end cut off entire- ly for tools like an awl or chisel. The small inden- tations will hold firmly in the wood if the end is fitted snugly; however a prick punch or a_ small hole with a brad driven in will keep the thimble in place on the handle. The round end of the thimble makes a very neat fitting ferrule that is not obtainable in the ordi- nary kind.—JAMES M. KANE. , Thimble on wood handle A Self-Translating Telegraph Line for Amateurs HOSE electrical experimenters who have possessed a private telegraph line know what fascination there is in communicating’ with a@ friend by this means and also know what a wonderful possibility of misunderstanding there is in such a device when the operators have only a speaking acquaintance with the Pear shape push button both. The draw- ing shows clearly how to connect the wires. A pear-shaped push button is used for the bell and connected in the usual way. The flash-light with its reflector is held in place by binding it with adhesive plaster. The switch consists of a piece of spring brass and a round head screw. After all the connections are made, the whole neck of the push button is wound with tape. Pushing the switch lights the light, push- ing the button on the end of the push button rings the bell. Two cells of dry battery will be sufficient to work either the light or bell—ALBERT E. JONES Bell 7" Dry cells A battery lamp on push button SS SSS SS om Wal Forty divisions around the face of the wheel for necessary alphabet characters standard telegraph code. There is no doubt that many more amateurs inter- ested in electricity would have such a line Mm ct 2 i ie ee ee ee ee” le ee eee ee ee i. Se

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ee were it not for the difficulty of learning the code sufficiently to understand what comes over the wire. And it is to make possible a line which sends automatically and automatically translates its signals that the device illustrated herewith was developed. The principle made use of involves the so-called ‘‘step by step’? method of pro- ducing synchronous motions at separated points and makes use of the ordinary tele- graph sounders and keys and the ordinary battery. Reference to the drawings will show that there is provided a flat wooden wheel having around its periphery forty di- visions to correspond to the forty neces- sary characters of the alphabet including the numerals and the necessary punctua- tion marks. To the shaft of this wheel is rigidly attached a thin metal rachet wheel, The wood wheel with a thin ratchet wheel attached to turn it as the sounder works such as can be purchased at the store of any gear supply dealer, having forty teeth. This shaft is mounted to rotate rather stiffly between bearings formed by screws having holes drilled in the tips, the shaft being pointed at either end to bear in the holes. The bearing screws are mounted in wood pedestals, as suggested by the drawings, and the whole mounted on a suitable base. A telegraph sounder, or any similar arrangement of magnets and lever, is arranged under the wheel and has mounted at the end of the lever a thin piece of spring metal which is bent so as to form a hook to engage with the ratchet. As will readily be seen this arrangement causes the letter wheel to revolve through the space occupied by one letter every Popular Scvence Monthly 953 time the sounder arm is drawn down. There is also another piece of flat spring metal to prevent the wheel going back- wards and also to press on the ratchet continuously so as-to prevent it turning too freely and thus getting out of time. From the above description, the use of the apparatus will be plain. There is provided at each end of the line one of the letter wheel machines, a telegraph key and a battery, all connected in series as in an ordinary telegraph line. When one wishes to transmit he opens his key lever and makes “dots” until the letter he wishes comes to the opening in the shield over the type wheel, then he pauses long enough to let the receiver know that that letter is to be copied, then proceeds to the next letter and soon. The end of a word is signified by a space, and the end of a sentence by a period or question mark. The method is, by its very nature, slow, but is quite accurate, which is more than can be said of the ordinary amateur Morse line. After some practice, fair speed can be obtained though. Certain refinements naturally suggest themselves to the amateur—such, for instance, as having an extra wire or a duplex circuit to force a strip of paper up against the wheel, which would have rubber type set on it, thus producing a printing telegraph. It is also evident that the line described is a closed circuit line and consequently gravity batteries should be used as the current flows all the time when no message is being sent. This is, of course, the most reliable type of line, but there are many well-known ways of producing an open circuit line on which ordinary dry batteries may be used. Another method requiring a fair amount of interesting developing work is to use low frequency alternating current produced by a magneto generator to operate the apparatus. Thus, when it is desired to send a letter, the key is simply held down till the natural pulsation of the current has brought round the proper letter, when it is released for a moment. This method is entirely practical and well worth the trouble of constructing it. On lines running more than 100 ft. it is very desirable to use relays, as the current re- quired to operate the letter wheels is too much to transmit any distance without serious loss in the line.—CHAS. HORTON.

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954 Popular Science Monthly Interesting Method of Learning the Telegraph Code N learning either of the telegraph codes one finds it easy enough to learn to transmit correctly without the aid of Fig. A metal ball rolling in V-shaped notches having alternate contacts and insulation any other person, but, when it is desired to learn to receive, it becomes abso- lutely necessary either to have a teacher or some kind of apparatus to take his place. There are very few students who can afford the services of a teacher and consequently the majority must secure some sort of mechanical device to make the signals. There are several of these devices on the market but as a rule the price is a good deal beyond reach. Fur- thermore, in these mechanical transmit- ters there is not enough of the element of chance; that is, when one has used one of these instruments for a short time he gets used to the combinations employed to such an extent that the instrument loses its usefulness. In learning the code quickly it is absolutely necessary that one never know what letter is coming next and it was to provide an arrangement in which the element of chance enters that the ap- paratus herewith described was developed. Reference to Fig. 1 will serve to give an idea of the method used. The princi- ple in use is to provide a V-shaped trough, for a metal ball to roll in, and to cover the sides of the trough with metal pads so arranged as to correspond to the telegraph signals. When the ball is caused to roll over the signals it makes corresponding contacts and a_ buzzer or sounder repeats them. Thus in Fig. 1, A is a baseboard and BB are metal angles fastened to the board so as to form troughs, CC, be- tween them. In each trough is glueg pieces of paper or other insulation bent at right angles, as at EE, so arranged along the length of the trough as to form the signals. The arrangement of the parts is clearly shown in the view, Fig, 2 which is a corner of the apparatus with the cover and the front removed. [t will be seen that there is provided one trough for each letter and numeral of the telegraph alphabet and the insulating pieces are pasted in to correspond to the characters forming each letter. The author uses forty characters; 26 for the letters, 9 for the numerals and 5 for punctuation marks, etc. A cover for the box is to be made of wood or cardboard so that the ball will be prevented (when the cover is on) from jumping from one groove to another. The simplest method of using the ap- paratus is to take it up with the two hands with the cover on and by tilting the box to cause the ball to roll back and forth through first one groove and then another, thus producing signals at ran- dom. It will be evident after .a little thought that signals will be produced with this form of the apparatus only when the ball rolls in one direction for all letters except those which are symmetri- cally arranged, as for instance, D, E, The ball may roll into any one of the notches without the operators’ knowledge etc. It will be evident to anyone with the ability to build the apparatus that a passage could be provided for the return of the ball so that meaningless signals would be prevented and also that a pivoted frame might be constructed so

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that the apparatus could be worked with one hand, leaving the other free to write the characters as they are produced. It is also possible to construct the apparatus in circular form by arranging the troughs around a conical piece and have the palls pushed one at a time up through the center of the cone to fall in one direc- tion or another down the cone and enter one or other of the troughs and then re- turn to the passage in the center to be pushed up again. It is further evident that a magnet might be arranged in con- nection with the above arrangement so that as soon as one ball made a contact after finishing its character the magnet would push up the next ball. Thus the machine would be entirely automatic and the operation continuous. This ar- rangement would make a very effectual apparatus for rapidly learning the code. The apparatus, in order to continue to work properly, should be kept clean so that the ball will make perfect contact on the sides of the trough. For cheap construction thin shiny tin should be used as this will not tarnish if carefully kept. A better construction is to make the angles of thin brass and have them nickel-plated. Ordinary steel ball-bearings will be satisfactory, but brass balls nickeled are better. Home- Made Electric Furnace for Heating with Arc Light N electric furnace of the arc type can very easily be made by anyone from the following materials: fire clay, as- bestos fiber and water glass. A mixture of these ingredients will quickly dry and harden into a fireproof mass of low heat conductivity. To make the furnace, select a box about 8 in. long and 4 in. square. Bore a hole a little above the center of each end just large enough to take a standard lighting carbon. Then mix some of the fire clay, asbestos fiber and water glass together, until a doughy mass is obtained and pack a layer 1 in. thick in the bottom of the box, forcing it down as firmly as possible. Now insert an ordinary glass tumbler in the center of the box and two wooden pins the size of light carbons in the holes at the ends. Around these pack as firmly as possible more of the mixture, filling the Popular Science Monthly 955 box completely. Smooth off the top and fill in the small cavities with a mixture of fire clay and water glass alone. In sim- ilar manner make a cover of the same size and about 1 in. thick. Place the box and Cross section of the box filled with the mixture around the pins and tumbler contents, together with the cover, in some warm place, preferably on the top of a furnace, and allow them to dry for about ten days. At the end of that time the box may be broken away and the pins and tumbler removed. To improve its appearance the outside may be retouched with a little fire clay and water glass. The result is a very efficient arc furnace of practically indestructible material which can be used in series with a suitable re- sistance on any house lighting circuit for many experiments. A Simple Way of Cutting Mica V-Rings to Fit on an Armature N armature winder often experiences much difficulty in cutting a V-ring from a sheet of mica so that it will fit properly. A simple method of getting an exact fit is as follows: We will assume that the bevel surface to be covered with mica is a section of a cone, the apex of which would extend to the heart of the shaft at a point which would be the inter- section of two lines, drawn as the contin- uation of the beveled surface of a V-ring, toward the heart of the shaft. First, draw a perpendicular line, A A, on a mica sheet. Measure diameter of the large end of the V-ring with calipers. Place the measurement line, B B, at right with line, A A, taking care that the line, A A, cuts the line, B B, exactly in the center. Next, measure the diameter of the small end, and make the line, C C, parallel to, and at a distance from line

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956 Popular Science Monthly B B, equal to width of V-ring. Connect lines B and C on both sides, extending lines to A A. Call this intersection point F, or ‘apparent apex of cone.” Using F as the center and B as the radius, describe a large arc. Repeat this operation using C as the radius. This gives us proper curve and width of the Diam. large end —_—— | Diam. small end ; Width of ring, . 8 on A N ae | D \ ‘ \ H . \ ; t he . ! 7 E “ \ 4 ~~ ‘ ! raf ff / ‘\ hi es SM Bytes apea Wee" OF Cone F Method of laying out a pattern for cutting the mica V-rings used on armatures mica V-ring, but to eliminate waste the length should also be known; the exact length is not needed and would be im- practical for two reasons; first, it would involve too much figuring for the average armature winder and take up too much time; second, because provision must be made for welding mica V-ring ends to- gether. Therefore the exact length would be too short. To get the required length, en- circle the large end of a V-ring with a piece of banding wire, allowing an extra inch for welding. Set this measurement on the large arc, and mark off the points, D D. Connect points D D with the apex, F. The V-ring is now all laid out and ready to cut. A Holding Clip for Making Tests on Spark Plugs HEN testing the spark on a set of exposed sparking plugs most car owners feel the need of special clips to _ grip the plugs, which have a habit of tumbling out of contact, more particu- larly when single plugs are being tested with the engine running. Under these circumstances, too, there is a riek of straining the magneto or coil if a plug swings past its wire without a ground An ordinary bicycle pump clip of the double spring type makes an excellent plug holder. One end may be sprung over any convenient pipe or bolt and the inverted plug dropped into the empty end, Controlling an Oil Cup by Means of an Electromagnet tie magnetically operated oil cup described herewith will be found to be a very convenient means of controlling oil feed in partially inaccessible places, An electromagnet is used in this scheme, as shown in the sketch. To open the oil cup, energize the magnet by control switch or push button. The iron disk, ad- jacent to the electromagnet, becomes mag- netized and draws up the iron cap on the top of the oil feed pipe, and the oil wil] commence to drip. Upon breaking the circuit, the disk is demagnetized and the oil feed pipe, being no longer attracted, again falls and closes the feed hole. Regulation of the flow can be obtained by adjustment of the iron disk, which is Adjustable resistance — ..__ Remote control (key or sw) “wm, es ION screw rod SO dis : ieee Iron car oi teed pipe aa ae Oil cup A serviceable elec- tromagnet that draws the oil cup plunger by electric current controlled at a convenient point connected to a screw rod, as shown. A small electromagnet and a rheostat in series in the circuit will render the control of the oil cup quite precise. This device has considerable worth.—PETER J. M. CLUTE. oo 8)

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Wireless Work in Wartime XI.—Radio transmitters using synchronous and quenched gaps By John V. L. Hogan chronous operation of a rotary gap in the wireless transmitter of Fig. 41 was decribed, for conditions which gave two or three sparks for each half-cycle of alternating current power. The curves of condenser discharge are shown in | = ae ond [' last month’s article the non-syn- Power transf. Fig. 41 il A diagram of a radio transmitter with a rotary spark gap interposed in the apparatus Fig. 42, where the divisions along the horizontal line represent six-hundredth parts of a second. Since the dashed wavy line shows the voltages at which the gap will permit a spark to jump, as time goes on, and the solid wavy line indicates the potential available (in the condenser) to produce a spark, it is evident that the discharge must pass whenever the two curves cross. If we now adjust the studs so that they are somewhat nearer together, permitting the spark to pass at a lower voltage (or if we raise the maximum charging potential to a higher value), it is clear that the overlaps will occur more often and that it will thus be possible to secure four sparks in each half cycle of charging current. By proper selection of the break-down and charging voltages, by changing the wave-form of the charging voltage, and by using a power transformer which will put energy into the condenser quickly after each spark passes, it is possible to get a large number of fairly regular sparks per second with only a low fre- quency of alternating current power. 957 The curves of Fig. 42 are not complete, since the secondary condenser voltage will be bound to be reduced by the with- drawal of energy for each spark; never- theless, a sufficiently ‘‘quick’’ or closely- coupled power transformer will build it up again before the next sparking time, so that the general conditions will be as indicated. For every spark there will of course be produced a group of radio frequency alternating currents in the oscillation circuit. With the non-synchronous meth- od of operation these will not be of the greatest power obtainable from the same amount of input energy. This is because the condenser is not dis- charged at the instant it has been filled to its fullest (maximum potential) point for each spark. It has been pointed out that for a given capacity, the amount of charge depends upon the _ potential; obviously, then, if the condenser is dis- charged through the spark gap at a voltage of 7500 there will be less energy for conversion into oscillations than if the charge is held until the full potential of 10,000 volts is reached. The greatest utility of the non-synchronous method lies in the fact that with it one is able Volts 15000 rn nw tn ee re p So a8 FS 88 fo ek be Te ae Fe oe ee ee ee it HU 10000 |'; :! RT art | rn tet cue rg ti 5000 0 +—+—+—+ _- + = 5 10 1S 20 Time Fig. 42 Curves showing the operation of the non- synchronous spark gap for a wireless set to secure a fairly good and moderately high-pitched spark tone from low fre- quency alternating current, even though at some sacrifice of conversion efficiency. By adjusting the gap for best regularity of operation, with the fewest possible

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a ae ee pat Oe TR eee eee 958 : “‘missed sparks,’”’ a clear chord-like tone is developed. This tone, when heard at a receiving station, is much easier to read in the presence of strong atmospheric disturbances than is the low frequency rattle produced by 60 cycle current and a fixed simple spark gap, such as shown last month, and the increase in signalling effectiveness thus gained more than compensates for the loss in conversion efficiency. 99 Operation of the Synchronous Gap What would happen if the rotary gap were slowed down until only one spark could pass per half-cycle of condenser voltage? This will depend mainly upon two factors: first, the instant at which the minimum break-down potential of the gap occurs, with respect to the condenser voltage curve, and, second, the value of the minimum break-down potential for which the gap is adjusted. To get the best results, the gap should reach its break-down point just at the instant the condenser reaches its maximum charge, as shown in Fig. 43. Here the dashed line again represents break-down voltages, and it is seen how the gap reaches its favorable position for sparking just as the condenser secures its maximum charge. To maintain these conditions it is neces- sary to mount the rotary gap element directly upon the shaft of the generator which produces the alternating current for the power transformer, so that the time-relation between the two variables will be strict and unchanging. A careful adjustment must be made, by moving the fixed electrodes backward or for- ward around the circumference of the gap, so that the shortest gap length occurs just when the condenser is ready for discharge; otherwise no spark will pass, or else only part of the energy will be drawn from the condenser at each dis- charge. This method of working is called the synchronous discharge, since the applied voltage and the gap-discharge voltage vary automatically together or synchronously. It provides what is probably the best method of securing maximum power together with a spark regularity so perfect that a clear musical spark tone is had at any frequency. To get high pitched spark tones, how- ever, a fairly high frequency alternating Popular Science Monthly current must be used, since there is only one spark for each half cycle. Thus 500 cycle current, as shown in Fig, 43 will produce a spark tone of 1,000 ig pulses per second. As before, each dis- charge generates a group of radio fre. quency oscillations in the primary circuit consisting of the condenser, spark gap and inductance L, (of Fig. 41). It should be noted that in general the non-synchronous method of operation involves the use of a rotary gap driven by a separate direct current motor with- out any particular relation to the input frequency, and that the sparking and missing times occur at random. In Fig, 42 is shown a perfectly adjusted relation Volts ? 15000] — r~ r™. P a a ie ie 10000 os ey ee, aay $000 0 1 2 3 4 Time in thousandths of al Fig.43 Break-down point should be reached when the condenser reaches the maximum charge between the gap frequency and that of the applied current which is almost im- possible to hold in practice, although it may often exist for short times. With the separately driven gap it is possible to slow down the discharge frequency until it is exactly twice that of the applied alternating current power, and so to ap- proximate the synchronous discharge condition. It is impossible to maintain the instant of ‘discharge correctly in phase (or in step) with the power current in this way, however, and consequently for best synchronous operation, the direct mechanical connection of the rotary gap and thegenerator, must be relied upon. Construction of the Quenched Gap . A fourth type of gap, shown in Fig. 44, is largely used in spark transmitters. This usually consists of highly cooled enclosed parallel sparking surfaces, often of silver, which are mounted in pairs and separated only about 1-100 in. The sparking potential of such a gap unit is about 1,000 volts, and to build up the breaking-down potential to a higher value

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nected in series. This construction has received the name of “quenched gap,” since when it was first used it was pre- sumed to have an especially effective quenching or extinguishing action upon the spark passing across it. The quench- ing action is now generally held to be more dependent upon the correlation of circuit adjustments than on the gap structure itself, however, as will be explained later, and the gap is merely one form of device which is capable of giving extremely uniform operation. This regularity of operation depends largely upon the fact that the current through the gap is kept small, and the surfaces are kept clean and parallel, so that successive discharges take place from different portions of the discharge plates. Thus extreme heating of any one point is prevented, and the gap may be relied upon to discharge at a quite definite potential time after time. The basic operation is exactly as in all the other spark gaps considered. The construction shown in Fig. 44 involves plates having cooling flanges, separating feet and the silver sparking surfaces in- dicated respectively by F, G and H, which are placed face to face (spaced accurately by the insulating gaskets J) in pairs as shown. The entire group of from six to thirty or forty units is clamped together in a special form of rack. This quenched gap is connected into the normal circuit of Fig. 41, replacing the rotary gap there shown. For best operation it requires a circuit adjustment somewhat different from that used with the rotary gap, since with ‘‘quenching”’ operation the endeavor is to transfer the energy of the radio frequency oscil- lating currents across the transformer with primary L,, into the antenna cir- cuit, in the shortest possible time. Under these conditions, the gap discharges so regularly that a pure musical signal tone is heard at the receiver. The tech- nical differences between so-called “‘quench- ing” and “non-quenching”’ operation may be understood from a_ study of such authoritative treatises as Ze- meck’s ‘Wireless Telegraphy”’; the princi- ples given in the foregoing are sufficient to bear in mind during the first survey of the action. The war-time student requires only such a grasp of the general subject Popular Science. Monthly a number of the units or pairs are con-— 959 of radio as will permit him to get into practical field work at the earliest moment. Production of Radio Waves The oscillating currents of the con- denser circuit (Fig. 41) are transferred into the antenna and ground circuit by the transformer action of coil L, upon its secondary. Similar radio frequency cur- rents are consequently generated, in groups, in the aerial wires which stretch up- ward to the mast top. These anten- nacurrents result in the production of radiant ether waves of the same radio frequency. The wireless waves pass outward over the surface of the earth, in all directions, at the speed of 186,000 miles per second; some small portion of the radiated wave energy reaches the receiver to which the messages are sent. The closing articles of this series will take up the interception of the radio waves at the receiving station. Fig.44 Separating feet and sparking surfaces Mind Reading by Wireless—Try It on Wise Friends HE mind reader bounds up every few months. The feats he can perform are little short of marvellous. William Dubilier of New York has given the fol- lowing details to the PopULAR SCIENCE MONTHLY of how many of these mind readers work. Any wireless enthusiast can set up equivalent apparatus and obtain equally good results. Dress yourself or a friend up as the mind reader. Oriental costumes are all the style in the mind-reading profession, and in this case are especially necessary because a Turkish or Indian turban makes an excellent headpiece by which the mind reader can conceal a pair of tele- phone receivers clamped to his ears. Around his body just beneath the shoul- ders are wound some 100 turns of No.

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960 30 double cotton-covered copper wire, the ends being directly connected to the receivers. All wiring is of course con- cealed by the mind reader’s cloak, his turban, and perhaps a high collar of some sort around his neck. Wired up in this way, the mind reader is ready for action. But the mind reader must have an accomplice. The idea is that some mem- ber of the audience before which exhibi- tions are given be requested to show some- thing to this “friend’’ (the accomplice), whereupon the mind reader will tell what it is. For instance, the ‘friend’ may be shown a watch, and the mind reader requested to tell what time it is. Or perhaps the object exhibited happens to be a newspaper and the person with occult powers is asked to tell what head- line the exhibitor has his finger upon. Many such tests can be devised. Around the accomplice’s body just beneath the arms, in the same way as in the case of the mind reader, are wound about fifteen turns of No. 16 double- cotton-covered wire. This serves as a sending “‘aerial,’’ while the turns on the mind reader serve as a receiving ‘‘aerial.” As shown in the diagram, the turns of wire on the accomplice are in series with several cells of flashlight battery concealed in some manner on his person. hes “< Tis uF iat 4 / ) =

Receivers

| Buzzer

Diagram showing the arrangement of parts on the body for mind reading sending and receiving Also in the circuit are a key and a small, almost-noiseless buzzer, likewise con- cealed. When the person who sets out to test the mind reader’s powers holds something up before the accomplice, the accomplice

Popular Science Monthly of course reads it, or otherwise notes what is necessary, and telegraphs the information to the mind reader over the miniature, short-range wireless just de scribed. The accomplice may have his key in a coat or trouser’s pocket and manipulate it by a hand “carelessly”’ placed there- in, or he may have the key in a shoe and operate it by pressing with a toe. In this last case con-

The audience being entertained by a seem- ingly miraculous way of mind reading siderable skill is necessary, but by diligent practice professional accomplices some- times attain great proficiency. The accomplice may wander anywhere about the room, wherever he may be called, in fact, by those who desire to test the mind reader’s powers. Still the wireless works regardless of the changes in position. By pretending that peculiar psychopathic influ- ences exist between accomplice and mind reader, the illusion may be heightened. The audience will won- der how any two persons can carry on thought transference to any such great extent. Yet the initiated wireless man knows! While the amateur is now barred from using his wireless instru- ments, this idea presents a new and interesting way of making use of parts of his apparatus and of keep- ing in practice in sending and re- ceiving. It also provides entertain- ment for his friends. The apparatus is not difficult to construct and it may be used many times in school work or for private theatricals as a paramount feature for the evening en- tertainment. Amateurs who have put the idea into execution are enthusiastic regarding it.

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ee | Popular Science Monthly i \ SZ 92-492 | a ince Ae Pac: i Po THE SACK | 2 THAT SAVES “» YOUR BACK Simply a few pulls on its chain and the heaviest car is raised or lowered without danger and without exertion. Every motorist has dreaded using the ordinary jack—an unpleasant operation, to say the least, and constantly fraught with danger and much tiresome work. Now all the unpleasant, disagreeable features have been entirely eliminated by the Weed Chain-Jack. With it, whether raising or lowering the car, you are always out of harm’s way—No knocking of head, or soiling of clothes against springs or other projections—No skinning of knuckles or flying up of a “‘handle’’"—No chance of the car coming down, often resulting in serious bodily injury—Infinitely easier to operate than any jack on the market. To operate a Weed Chain-Jack it is not necessary to get | Once in place you never have to toucha Weed Chain-Jack. down ina cramped, strained position and grovel in the mud, grease or dust under a car to work a “handle” that is apt to fly up, with unpleasant results, To lift a car with the Weed Chain-Jack, simply give a few pulls on its endless chain while you stand erect—clear from springs, tire car- riers and other projections. To lower a car pull the chain in opposite direction. Up or down—there’s no labor. send $7.50 for any size for pleasure cars or $15.00 for the Truck size, and we will send you one, all charges prepaid. For delivery in Canada send $8.50 for any size for pleasure cars or $16.00 for You do not have to crawl underneath to either raise or lower the car and after the car is lowered, you haul the jack out from under the car by the chain. Much superior in safety, economy, utility, simplicity and construction. You will never be satisfied with any other if once you use a Weed Chain-Jack x, un. Powerful—Safe—Easily Operated Has a strong cap, providing the kind of support from which an axle will not slip, while a broad Fase | —— ee jack a be ogre ning = — agape gone | bay age oe — = rg pow | to apres American | an support over twice the weight it is ever required to . ever gets out of order. Gears 3 H and chain wheels protected by a stamped-steel housing. Chain heavily plated to prevent rusting. 4 Chain Co. Inc. | MADE IN FOUR SIZES ee inch —_ 10 ee pag Fd —~y¥ Dept. 2 | a an auxiliary step as illustrate a ‘ | Size Height When| Height When (Height When Raised Price above. When in operative position 4 Bridgeport, Connecticut Lowered Raised | When Aux. Step Up this step adds two inches to the 7.60 | 3 inch b inches 12 1-2 inches| 14 1-2 inches |$7.50 height of the jack. m Gentlemen: Enclosed find $,3-50. ine i -8 i h 4 = [| cinch | inches |IRG3 inches] Kotmursiey | 189 10 Days’ Trial Send _me 2 Weed Chain-Jack- inches |19 1-4 inches} No Aux Step /15.00 If your dealer does not have them stood Lam to try it for 10 days, and if not satisfied I am to return it and you will refund the purchase the Truck size. Try it 10 days. If not satisfied, return it to us and we will refund your price. } Money. Use the coupon. j/American Chain Company, Incorporated | Bridgeport, Connecticut } In Canada: Dominion Chain Company, Limited, Niagara Falls, Ontario NOME... ose rece eeeeeeenseeeeccess Largest Chain Manufacturers in the World a When writing to Advertisers please mention Popular Science Monthly | The Complete Chain Line—all types, all sizes, all finishes—from plumbers’ safety chain to ships’ anchor chain

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a (x) poooneaoccs f) |) OIC ACI "If stl Ht | Hh AC aI wy ull WCU WT Mall ddetlatattal haat Ababtbatatta ti Wi i Mododbatbotattetinanbatotadatttatttntatfatbetbatatfatlinatltadtb Ab tallln PY oR Popular Science Monthly PON Ae rmorplate your floors en Pe ae ence aA Well varnished floors and woodwork grow Mark X before subject that imerests you and Mail This Coupon to * E. I. Du Pont de Nemours & Co. Advertising Division WILMINGTON P.S.M. DELAWARE Vitrolac Varnish Vitrolac Stain Finish Flowkote Enamel Sanitary Wall Finish Town and Country Paint Industrial Paints Antoxide Iron Paint Py-ra-lin Toilet Goods Challenge Collars Fabrikoid Upholstery Industrial Dynamites Farm Explosives re ed old gracefully. Time mellows their beauty. Dust and liquids may settle on the surface. But they cannot get under to mar the delicate grain of the wood. HARRISON’S VITROLAC VARNISH (A Du Pont Product) is really floor armor—tough, durable, brilliant and luxurious—proof against scuffing feet. Protect and preserve the delicate natural grain of your floors and woodwork. Banish the embarrassment of spots and stains and save excessive house work. Check “Vitrolac Varnish” in the coupon. Let us tell you the complete story. HARRISON WORKS Owned and Operated by Send it in: E. I. Du Pont de Nemours & Company Wilmington, Delaware Visit the Du Pont Store, 1105 Boardwalk, Atlantic City, N. J. Philadelphia, Boston, New York, ae Kansas City Chicago, ¥Y YUY’U440t %¢EG¢eZyi My, Ut ty ¥ Yh Ya, iT AMERICAN INDUSTRIES Gio AAMAS A LAC Ae —— MMM MMI, Cea TTT nm COU CU POND Te Me | When writing to Advertisers please mention Popular Science Monthly Gear Shifter —_— Fast,slow or locked, at a finger-touch

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Popular Science Monthly he G ka | aaa + \ Efficiency tools! —you’ve always wanted them. Now extraordinary industrial cordi- tions demand them. “YANKEE” Tools save a fourth to a half of a man’s time; require less skill; less labor; enable better work. For example:— “Y ANKEE” Bench Drill woo, does away with hand feeding. It has the exclu- sive “YANKEE” Friction and Ratchet Feeds. Automatic! A quarter turn of the tiny lever (see illustration) and the rapid Friction Feed runs drill to contact; then acai the Ratchet Feed automatically takes up the work, maintaining a posi- ‘e100 Tile tive, even pressure all the way through—saving drills and leaving one “—_ hand free to hold the work. Reverse the little lever, and drill is easily and quickly withdrawn. Gears can’t jam or strip, because Feed is automatically thrown off at either extreme. Gear Shifter Fast,slow or locked, at a finger-touch Speed and efficiency! No time lost; no adjustment; no guesswork; nothing to go wrong. Multiplied man power! Especially in demand for shops and garages not equipped with power. *““YANKEE”’ Bench Drill No. 1005. Two speeds. 3-jaw chuck, holds drills up to Winch. Height, 28 inches. Price (Philadelphia) $16.50 **“YANKEE”’ Bench Drill No. 1003. One speed. 3-jaw chuck, holds drills up to 4 inch. Height, 1834 inches. Price (Philadelphia) $10.00 “YANKEE” Vise No. 990. Accurately machined sides, ends and bottom, for hold- ing work on bench drills. Swivel jaw for taper work; groove for rounds. Base, 6 in. long, 234 in. wide. Price... $2.20 eo ee | Your dealer can supply you Write us for ‘‘‘Y ANKEE’ Tool Book''—free. Tells how to save time and labor in working in wood and metal. NORTH BROS. MFG. CO., Philadelphia When writing to Advertisers please nention Popular Science Monthly

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Popular Science Monthly Is There a Thrift Card in YOUR Pocket? S you sit and read, you thank your stars that the war IS “over there’”—and not here at your door-step. And you feel grateful to the boys in khaki who are KEEPING it and WINNING it “over there.” Turn Your Gratitude Into War Savings Stamps The spare quarters that you invest in War Savings Stamps and Thrift Stamps help Uncle Sam to clothe, to feed and to arm those boys in khaki. When you have accumulated sixteen Thrift Stamps, cost to you $4.00, you exchange them by paying from 13 to 23 cents, according to the month of 1918 in which you make the exchange, for a War Savings Stamp for which the Government will pay you $5.00 in January, 1923. This is equivalent to 4% interest compounded quarterly. A safe and remunerative investment. Ww. Get a Thrift Stamp, pasted on a Thrift Card, oe We Je TO-DAY—at any post-office, bank or trust com- ‘WAR SAVINGS STAMPS pany, drug, cigar or department store, or the many 188UED BY THE : ; UNITED STATES, other places showing the W. S. S. agency sign. GOVERNMENT Contributed through the Divi- sion of Advertising United States Gov't Comm. on Public Information This space contributed for the Winning of the War by AMERICAN TELEPHONE & TELEGRAPH COMPANY, New York When writing to Advertisers please mention Popular Science Monthly 22 Gmemuneeemen

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Popular Science Monthly as Ss Why the Gillette Gillette Safety Razor Have You Seen the New Gillettes Specially Designed for the Fighting Man? HESE models were designed by members of the Gillette Organization who have seen service with the Colors and know what the soldier is up against. Hundreds ef officers and men are buying them—the U. S. Service Set in metal case, and the new Khaki- covered sets for Uncle Sam’s sol- diers and officers. The Gillette is the one razor for the man who is doing things—the one razor with world-wide use and reputation. When a man wants new Blades he can get them at any Post Ex- change or Y. M. C. A. Hut— heze in America or Overseas. Our Paris Office carries stocks— is constantly supplying the Ameri- can Expeditionary Forces. Gillette Safety Razors and Blades on sale everywhere in France, England, Italy and the Eastern battle fronts. Is Especially the Soldier’s Razor Taere isn’t a harder shav- ing job on earth than the ser- vice demanded of the Gillette by the fighting man. Under the very worst pos- sible conditions of climate — with cold or hard water—on sun burned or wind-chapped faces—the Gillette is called upon for its solid-comfort, velvet-smooth shave. And delivers it. There are more Gillettes used than all other kinds of razors added to-gether—the compact, complete razor with no strops or hones to clutter up the kit. Hundreds of thousands of officers and men have adopt- ed the Gillette—with its blades always sharp, always ready. No Stropping, No Honing. GILLETTE SAFETY RAZOR COMPANY BOSTON, MASS., U. S. A. Gillette Safety Razor Company, of .Canada, Ltd. 73 St. Alexander St., Montreal Gillette Safety Razor Societe Anonyme 17 Bis, Rue La Boetie, Paris, France Gillette Safety Razor, Limited 200 Great Portland St., London, W., England A. G. Micheles 53 Liteiny, Petrograd, Russia Vedova Tosi Quirino & Figli, Via Senato, 18, Milan, Italy When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly We Congratulate the Electrical Industry on the occasion of the Forty-first Convention which marks thirty-one years of epoch-making activity by The National Electric Light Association This year, more than ever before, the Industry and the Association have cause to be proud of what its men and women have done and are doing to promote the vital interests of our Government and our people The New York Edison Company At Your Service General Offices: Irving Place and 15th Street New York City . When writing to Advertisers please mention Popular Science Monthly know orgal Marl Ame learn also Winc Med. Corp sport senta from direc your

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agente Popular Science Monthly 11 Sia ee a Now there is a National Organization known as the Winchester Junior Rifle Corps, organized specially for the development of Marksmanship among boys and girls of America and to teach the correct use of a rifle. By joining this organization you will learn how to handle a rifle safely. It will also entitle you to compete for the famous Winchester Marksman and Sharpshooter Medals. There is a Winchester Junior Rifle Corps Headquarters in your town. Your sporting goods dealer is probably a repre- sentative. If you cannot get full particulars from him, write to National Headquarters direct for full information. Why not get together a dozen or more of your boy friends who want to learn more Take-down .22 caliber single shot rifle. A low priced, light weight gun made tn two sizes WINCHESTER uns and Ammunition World Standard When writing to Advertisers please mention Popular Science Monthly Start, in your town, a branch of the Winchester Junior Rifle Corps MERICA used to be known as a “Nation of Riflemen,” and it is up to every boy to help keep that title with us. about rifle shooting and organize a local branch of the National Winchester Junior Rifle Corps. Later on, when enough crack shots have been developed among you, the National Headquarters will arrange matches between picked teams from the different local branches. If neither you nor your chums own a .22 caliber Winchester you can buy one for a very reasonable sum from your dealer—who has a rifle to suit every boy’s pocketbook. It doesn’t make any difference what kind of model you buy, but it must be .22 caliber Winchester. It doesn’t make any difference in your shooting whether you get a low priced single shot rifle or a fine repeater. The accuracy of a Winchester is in the barrel and the same quality of steel and the same care in boring goes into all. Get started today. Go to the Winchester Junior Rifle Corps Headquarters in your town and register as a member. If you cannot get all the particulars there, write direct to the Winchester Junior Rifle Corps, National Headquarters, 275 Winchester Avenue, New Haven, Conn., Division 871. MODEL 0. Toke-down Repeating .22 caliber rifle, 20-inch round barrel. Shoots three sizes of ammunition. The most popular .22 caliber repeater ever placed on the market

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Popular Science Monthly The Graflex A reflecting camera that lets your eye see what the lens sees, before exposure, and right side up. You watch the ground - glass screen, adjust focus till the image of your picture grows clear and sharp— then snap it. Be See the picture IMPLICITY, speed, absolute control of focus and com- position — the satisfaction that follows increased certainty— this is the Graflex story. Auto- matic exposures from a tenth to a thousandth of a second; successful snapshots in failing light, where slow exposures with other cameras would result in failure; fully-timed negatives, in good light, of two-mile-a-minute motion that other cameras could never get. Ask for interesting booklet “Why I Use a Graflex”— free from your dealer or from. us. FOLMER © SCHWING DEPARTMENT Eastman Kodak Company Rochester New York When writing to Advertisers please mention Popular Science Monthly ~ 1 sonmepsen reurapqrmmeeoesn before you snap it | | | when auto, when

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Dry Batteries + When your engine faints— when truck, tractor, family auto, or motorboat chokes up and loses its gait— When your doorbell quits; when electric lanterns get the glooms; when tele- phones go hoarse— Install Columbias; they are easily and quickly wired up. With Columbias pouring current once more through the wires, everything will hum till the final vigorous kick has gone out of the cells; and they last long. No extra charge for Fahne- stock Spring Binding Posts. Popular Science Storage Batteries When the name Columbia was placed upon a storage battery, it meant some- thing of importance— It meant that a storage battery worthy of that mame had been created— For a quarter of a century the name Columbia has signified “the best in bat- teries.”’ No higher tribute could be paid to Columbia Storage Batteries than to say that they are Columbia. And there’s a Columbia Service Station or Service Dealer just a few doors away. Columbia is the Symbol of Supremacy NATIONAL CARBON COMPANY, Inc. Cleveland, Ohio In Canada Columbia Batteries are made and sold by Canadian National Carbon Co., Limited, Toronto, On- tario When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly * rN ti Se 2 “Not the name of a thing, tS ‘\ but the mark of a service” — ‘ya e | | From the incoming host of new ideas on light- ing, MAZDA Service se- lects for the makers of MAZDA Lamps, only those developments in design, materials and U: methods that will im- at} prove the light you enjoy | a The Meaning of MAZDA in MAZDA isthe trademark of a world-wide service to certainlamp | MAZDA Service is centered in the ResearchLaboratories of the Ti manufacturers. Its purpose is to collect and select scientific and General Electric Company at Schenectady, New York. The practical information concerning progress and developments in mark MAZDA canappear only onlampawhichmeet the standards the art of incatidescent lamp manufacturing and to distribute this of MAZDA Service. It is thus an assurance of quality. This Snformation to the companies entitled to receive this Service. trademark is the property of the General Electric Company. RESEARCH LABORATORIES OF GENERAL ELECTRIC COMPANY ™ Al When writing to Advertisers please mention Popular Science Monthly

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ea Popular Science Monthly 115 ‘‘ That’s the tire for me’’ ‘‘It has the stuff in it that means mileage. ‘‘How do I know? Say! “Do you see, that name, United States? I’ve had sev- eral United States Tires with different treads and they’re all good, believe me. ‘I’ve never seen the United States Tire that didn’t stand up. ‘“ This chain tread is the one I like best. It’s fast and easy and that chain sure does hold the-road.”’ Every boy who rides a bike will find the tire for him among the twelve different United States Tires. A tread and construction to suit every person, every pur- pose, and all : United States Cycle Tires are Good Tires Ask your tire dealer to give you a United States Tire Book showing all styles of United States Tires for Bi- cycles and Motorcycles. It has a lot of other interesting pictures and read- ing in it,too. Three popular Bicycle Tires are Chain Tread, white walls When writing to Advertisers please mention Popular Science Monthly with black rubber tread, Heavy Serv- ice Traction Tread, all white with motorcycle fabric and herringbone non-skid tread, and Cord Tire, made in the same manner as the famous ‘Royal Cord’ Automobile Tire. Ask to see them at your dealers. Be Sure It Is United States

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116 Popular Science Monthly Motocycle « with Powerplus Motor @ Lowest in Cost,Operatjgn,and Upkgam * se « ' : ' ' i Combined Utility, Pleasure and Economy ORE power and speed than you'll ever need. The greatest riding comfort due to the patented exclusive Cradle Spring Frame. An ease and sureness of control that lends zest tothe driving. Mechanical com- pleteness and simplicity that promotes relish for long, health-giving tours. The 1918 line of Indians offers a type and model mount for every- body at prices that meet every present-day demand. It embraces the Indian Big Twin, Side Car, Light Twin, Parcel Car, Electrically Equipped Bicycle, and twelve other model Bicycles. Illustrated 1918 Motorcycle or Bicycle Catalog sent on request Hendee Manufacturing Company | 725 State Street, Springfield, Mass. Largest Motorcycle Manufacturers in the World | UCM UOT CLL UTI | | When writing to Advertisers please mention Popular Science Monthly |

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Popular Science Monthly - Nine revel lelel.ee arelalel até) washwoman kee Yet! S washday the big problem of the week in your home? It need not be. You can solve it as well as your servant problem by using the Western Electric Washer and Wringer It does the hard work. It washes the clothes in a revolving cylinder of hot suds so that there is no wear or tear on them, and it does it all at a cost of about 3 cents for the average family’s wash. With the Western Electric Iron to help, the ironing is quickly and 4 pleasantly done, while the Western Electric vacuum cleaner, port- able sewing machine and other household appliances all help / you manage your home in an up-to-date business fashion. y 7 WESTERN Let electricity help you meet your particular prob- Gentiemen : lem this summer. Ask for Booklet No. 21-AT Please send me Booklet No. 21-AT WESTERN ELECTRIC COMPANY 4 wane ae INCORPORATED V7 7 _ New York Chicago Kansas City San Francisco // ‘ Houses in all Principa! Cities 4 Address When writing to Advertisers please mention Popular Science Monthly

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the United States Government GuASE “Tis like the hide in most. respects fn some respects tis better’. Upholstery Made by Sanford Mills | | Has the same rich appearance of costly leather and retains its first beauty after the hardest wear. ATTRACTIVE DURABLE PRACTICAL SANITARY ECONOMICAL This is the worth while uphol- stery material for motor-cars, passenger or trucks. Wrile for Samples. For Upholstery: GALLOWAY GRADE GIBRALTAR GRADE Fee OT eed ie ee 1 ee LS Ce ee ee a eer oe -_——e

Ail L. C. CHASE & Co., Boston ‘ New York Detroit Chicago San Francisco Leaders in Manufacturing Since 1847 Popular Science Monthly

When wri<ing to Advertisers please mention Popular Science Monthly

LF on the ))_ Spot with xs Genuine RADIATOR NEVERLEAK “Look for the Sunburst on the Can” A Liquid compound. Mixes with water in radiator. GUARANTEED to stop all leaks in 5 to 10 minutes. Will not clog cooling system, Saves $10 to $25 repair bills. Does the work or money back. 50c and 75cacan at dealers or sent direct. BUFFALO SPECIALTY CO. 365 Ellicott Street - Buffalo, N. Y.

“‘The LIQUID VENEER People”

i Route‘Map es \ \. vo iy q ~~ for 1 “| ~=“Automobile

"| Painters A Take the | Brush Road straight up = \—\

i thehillto <& 7 Success, iste he ligh Signe of Busin is to Use i Whiting-Adams BRUSHES For Automobiles Every Automobile Garage should havean Outfit of Brushes Every garage must have an outfit of brushesto use, and such as sell accessories should have an assortment of brushes to supply demands. There is @ WHITING- ADAMS brush made for every automobile purpose. Cleaning, scrubbing, polishing, dusting, uinting, stain- ing, varnishing, and all uses for which brushesare re- 4 quired. Over 10,000 kinds and sizes made. Send for Illustrated Litezature.Dept.O- A JOHN L. WHITING-J.J. ADAMS CO., Boston, U.S.A, Brush Manufacturers for Over 100 Years Whiting-Adams Brushes Awarded Gold Medal and Official Blue

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Popular Science Monthly

" Get a Long @ er Run for Your Money Just a little more fuel—and you’d have made it. But that “‘little more” was lacking and you were stuck, The New Stromberg Carburetor —goes further than supplying that “little more” gas. It leaves a lot after the amount you now use igs consumed. It insures the longest run for your fuel money—most miles per gallon. Saves money on every mile your car covers—savings that are too important to be overlooked by any motorist. Write for Free Literature. Give name—model and year of your car. STROMBERG MOTOR DEVICES CO., — Dept. 645, 64 E. 25th St., Chicago, Ill. New STROMBERG Does / CARBURETOR

distinct sparks , ° Wen. s RUBBER TIRES with the same juice ORDER QUALITY Ug, BU” ox Avprovar Save 15°030" Guaranteed 4000 Miles OU take no chance in ordering BUCK- Think of the added power your motor would SKIN Tires by mail because we send

ordinary plugs use

have if equipped with Twin Fire spark plugs. Each them on a money-back guarantee. And combustion complete less carbon, less trouble they save you from $20 to $60 a set, depending on the with pumping oil, and with the same current | size and make you now use. They're guaranteed to ordinary plugs use. a .. give 4,000 miles hard service, though ake Woe . many users get 8,000, 9,000 and 10,000

= @ Basket Weave : ; TLIN : FIRE Non-Skid Tread miles. We also repair all BUCK- A _ SKINS free at any time, no matter how far they have been run. BUCKSKIN TIRES Plain and Non Skid Guaranteed are perfect in construction. Made of finest rubber and most expensive cotton fabric, in a big, new modern plart by skilled workmen. We sell to yev direct—th 1s saving cost of middlemen’s com- missions » nd credit losses. This is why we can sell high quslity tires at prices from 15% to 30% less than you are now paying for other first-class tires, e Send for price list Express Prepaid and users’ testimo- nials. When check accompanies order, we ship anywhere in U. S.'or Canada prepaid. If in a hurry for tubes or tires, send size, type and whether plain or non-skid tread is desired and we will ship romptly. C.O.D. shipments, subject to inspec- on, if desired. Special discount on 4-tire orders. The L. & M. Rubber Co., John St., Carrollton, Ohie Manufacturers of Rubber Goods Since 1904 Western Distributing Office 1436 S. Michigan Ave., Chicago, Ill. 18-11

Has two spark gaps. If one clogs the other continues firing and the hot explosions soon clean the fouled point (not so with any other plugon the market). This is possible be- cause with Twin Fire the current is used twice—you are always sure of a hot spark. Ask your dealer or order direct —the price is only $1.00. TWIN FIRE SPARK PLUG CO., 666 Woodward Ave., Detroit, - Michigan DEALERS :—Twin Fire isn’t a bar- oe papel plug. Its retail price of 1.00 is strictly maintained. Back of each plug is our guaranty. We help youselland stand firmly back of you with the best constructed plug we can id. Our proposition toy < youis liber al get the details,

When writing to Advertisers please mention Popular Science Monthly

Page 210

Popular Science Monthly E 20 DEMOUNTABLE A tire changed in 60 seconds—One nut to un- screw, that’s all you do DRIVE. this Summer, free from tire changing an- noyances. Carry yourspare tire on the Minute De- mountable Wheel. You'll get more mileage out of your tires. No mud encrusted rim to pry off. No more soiled hands, wilted collar, ruffled temper or lost time. The Minute Demountable Wheel is backed by the H.S. Trademark of quality. Thousands now in _ use. Equipment consists of ex- tra wheel, interchangeable front or rear—four hubs to replace present Ford Hubs. You use the Ford Wheels. Simple to install. A quick tire change to meet the needs of doctors, women drivers, owners of Ford delivery fleets, every alert Ford owner. Price $30 Complete Denver and the West $35.00 We are filling orders to accessory deal- ers as rapidly as possible but would advise if you are in a special hurry for this equipment to write us direct and we will see that your dealer is given a shipment to take care of im- } mediate orders. Send for booklet giving complete information. Mention this magazine ana name of dealer. Address Dept. ‘‘E’’ Licensed under patents of the Wire Wheel ‘orporation of America On Witu THE Trip ST TOOK OMY A MINUTE! When writing to Advertisers please mention Popular Science Monthly er

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AtSraduation — HE most appropriate and most — beauty usually found only in more appreciated gift is a high-grade expensive timepieces. watch. In mahogany-finished, vel- There are other Chesterfield models, vet-lined gift boxes and encasedin — also, at almost any price you wish distintively designed, hand-wrought to pay. All are Extra- Thin, Solid Gold cases, the 21-Jewel stylish and handsome; and all are Extra-Thin South Bend Chester- | dependable timekeepers. field Watches at $125, $100 and _— See them at your jeweler’s, «A $80, and the 17-Jewel models at Book of Beautiful Watches’? will $75 and $55, offer accuracy and _be sent you on request. SOUTH BEND WATCH COMPANY 26 Studebaker Street, South Bend, Indiana For Years, Makers of Standard Railroad Watches South Bend The Wateh with the : Pere

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Two Points! Herearetheworld’stwomost famous writing points, the efficiency ends of the Eversharp Pencil and Tempoint Pen. WAHL EVERSHARP The Perfect Pointed Pencil —the point is always there, no matter how fast, slow, light, heavy, short or long you write. Eighteen inches of lead—enough for a quarter million words—obtainable in various degrees of hardness. And Eversharp efficiency is matched by a beauty of construction inside and out that makes you proud to own one. TEMPIIINT The Perfect Pointed Pen —the point of this fountain pen has a steel- like hardness and flexibility —unaffected by hard use or ink acids. Famous Wahl Comb Feed insures exact flow of ink. Air-tight chamber prevents “sweating” and keeps pen moist for instant writing. Made in both Self Filling and Screw Joint styles. (Heretofore known as the Boston Safety Pen.) Both Pencil and Pen are made for pocket, chain, or lady’s handbag. Pencil prices, $1 and up. Pens, $2.50 andup. At better dealers everywhere. Or, write for descriptive litera- ture to aid in selection direct. Dealers: Write today for catalog and interesting dealer proposition on these two splendid sellers. THE WAHL COMPANY 1800 Roscoe St., Chicago, Ill. Astor Trust Bldg., 5th Ave. & 42d St., N.Y. Pacific Coast Representatives CARDINELL-VINCENT COMPANY 577-579 Market St., San Francisco, Cal, Pencil i —the symbol of perfect writ- ing, the mark of che Eversharp and Tempoint Pen, thie sora eR af | af ‘ , 0 i/ 7 4 id 6 Be gi f | é

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PAIG The Most Beautiful ar 272 flmerica There is a world of satis- faction in owning a motor car that is a constant source of pride—a car that reflects, not only your good taste, but your sound judgment as well. The Paige is just such acar. Paige-Detroit Motor Car Co. Detroit lise Vil alleen ea Ndeds eanilealiacboan anit

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Make Your Recipe File Complete with Dishes Made from GRAPE JUICE with the Better Flavor Here is a simple Red Wing Dessert that will prove the quality and economy, of this delicious, full-flavored Grape Juice.. Try it. No matter how Red Wing. is used—whether as a base for flavoring, for punches, ices or desserts, it goes further because it is alf grape juice. "Phat is « why Red Wing ‘retains its richness, flavor, body and color éven: when appreciably diluted: When you want real grape: juice ask for Red Wing. Our free ° booklet gives many new recipes for both beverages and: desserts. Send for it. THE RED WING COMPANY, Inc. General: Offices. and Factories: Fredonia, N. Y. Branch Offices: New York and San Francisco

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Popular Science Monthly The Standard of the Firearms World For nearly a century Colt’s Firearms have played a dominant part in America’s glorious military history. Colt’s have been the standard of comparison in safety, quickness and efficiency, and have always stood the test in our national defense. Colt’s Firearms will give you ample pro- tection in your private life. Put your trust in the Colt name— your country does. Illustrated Catalog No. 106 mailed free on request COLT’S PATENT FIREARMS MFG. CO. HARTFORD, CONN., U.S.A. Revolvers Automatic Pistols ‘Automatic Machine Guns When writing to Advertisers please mention Popular Science Monthly

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A -Handfull of Muminating Efficiency hk PS T Operates from a storage battery, set of dry cells or of a Ford. Attaches to laacioanont board or drops inte dae pocket. Nitrogen bulb. Trouble Lamp rolled into one. _boat. Order one to-day. No risk to you. Read the Coupon, Weighs less than a pound. Equipt with 29 A Spotlight, Searchlight and fiorigti You need one on your Car or HAVE YOU A MOTOR? 72> See that groove of a LOOK! controlling the oil? The groove full of oil forms a dam. Gas cannot get down, surplus oil cannot get up. That’s why motor has more wer, DO carbon. ISN’T HAT A REASON? Popular Sizes 50 cents Write for free Booklet S AUTOMOBILE ACCESSORIES CO., Baltimore, Md. a LER| aT SUPPUES }| HASSLER DEALER |) M|~ OR ten days we want to transform your Ford into a $2,000 car. We will do this by putting on a set of Hassler Shock rbers. lf you are willing, we will take them back without question when the ten days have elapsed. But you won't bring them back. For Ford Shock Absorber Cars Don’t take another fellow’s word for it. Feel for yourself the ease and comfort, the smoothness found in a Hasslerized Ford. Hassler Shock Absorbers pay for them- sélves over and over again. Reduced tire bills, more miles per gallon of gasoline, one- third up-keep cost saved—all swell . the total of Hassler dividends. 300,000 Ford ers recog- nize economic neces- sity. Write today for Free Trial Blank, illustrated cir- [= cular and opinions of users. we ROBERT H. HASSLER, Inc. 593 Naomi St., Indianapolis, Ind. PATENTEO P fe Best and 5 Zi =-Z.1 Weapon for _o (The Boy Scout Weapon) 04 thrills him with 9 ane & joyous delight! The prong is made of beaytiful metal; never break wear out; scientifically made and best orkmanshi. Finest pair of rubbers you ever saw; they ar purpose and are more-elastic end lasti r re aan Z'p-Zip complete with severa' of ammunition, all for 50 cents. We pay postage. A wonderful littlepackage Shipped same day ordered, right from factory. Be sure the name Zip-Zip and our address appesr on the article you buy. e guarantee everything we make and refund money if desired. Order from us or any sporting goods store in your city, Send stamps, coin or money order. AUTOMATIC RUBBER CO. Columbia, S.C. When writing to Advertisers please Statement of the Ownership, Management, Circulati required by the Act of Congress of August 24, 1912, af Poon Science Monthly published monthly at New York, N. Y., for April 1, 1918. State of New York, County of New York, 88. Before me, a notary public, in and for the State and county aforesaid, personally appeared O. B. Capen, who, having been duly sworn according to law, deposes and says that he is the Business Manager of the Popular Science Monthly and that the following is, to the best of his knowledge and belief, a true state- ment of the ownership, management, etc., of the aforesaid publication for the date shown in the above caption, required by the Act of August 24, 1912, embodied in section 443, Postal Laws and Regulations, printed on the reverse of this form, to wit: 1. That the names and addresses of the publisher, editor, managing editor and business managers are: Publisher, The Modern Publishing Company, Inc., 225 West Thirty-ninth Street, New York, N. Y. Editor, Waldemar Kaempffert, 225 West Thirty-ninth Street, New York, N. Y. Managing Editor, Waldemar Kaempffert, 225 West Thirty-ninth Street, New York, N. Y. Business Manager, O. B. Capen, 225 West Thirty- ninth Street, New York, N. Y. 2.—That the owners are: The Popular Science Publishing Company, Inc., 225 West Thirty- ninth Street, New York, N. Y. Stockholders of Po Science Publishing Company, Inc., Henry J. Fisher, 22 William Street, New York, N. Y.; Oliver B. Capen, 225 West Thirty- ninth Street, New York, N. Y.; Robert Cade Wilson, 683 Springfield Ave., Summit, N. J., Waldemar Kaempffert, 225 West Thirty-ninth Street, New York, N. Y., George B. Agnew, 22 William St., New Yor, N. Y., Susan D. Bliss, 22 William St., New York, N. Y. 3—That the known bondholders, mort- gagees, and other security holders owning or holding 1 per cent. or more of total amount of bonds, mortgages, or other securities are: Importers and Traders National Bank, 247 Broadway, New York, N. Y.; H. J. Fisher, 22 William Street, New Yors, N. Y.; S. D. Warren and Co., 200 Devonshire St., Boston, Mass.; 4.—That the two paragraphs next above, giving the names of the owners, stockholders, and security holders, if any, contain not only the list of stockholders and security holders as they appear upon the books of the company, but also, in cases where the stockholder or security holder appears upon the books of the company as trustee or in any other fiduciary relation the name of the person or corporation for whom such trustee is acting, is given; also that the said two paragraphs contain statements embracing affiant’s full knowledge and belief as to the circumstances and conditions under which stockholders and security holders who do not appear upon the books of t company as trustees, hold stock and securities in a capacity other than that of a bona fide owner; and this affiant has no reason to believe that any other person, association, or cof- poration has any interest direct or indirect in the said stock, bonds, or other securities than as so stated by him. (Signed) O. B. CAPEN, Business Manager. Sworn to and subscribed before me this 18th day of March, 1918. Robert A. Macbeth, Notary Public, Kings Co., No. 322. (Seal). My commission expires March 30, 1919. mention Popular Science Monthly

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—_imeeesc cue Ee Ss Fe Oe Ve h6UFlUS SF SO-@ OB ORB DO MOS FS Sere SE GSs t '

Popular Science Monthly [EXCLUSIVE DETAILS I Pigs are Pigs and all pretty much alike, but it is the exclusive details in design #| and construction that put one motorcycle far above all others of its type in fi the qualities that insure service and satisfaction. EXCELSIOR — HENDERSON | . The Only Four Cylinder Automobile Type | <a Motor. Hand or Foot operation Motor Starter. | | 1

The Lowest Center of Gravity ever attained in a motorcycle. The Aristocrat of Motorcycles, combin- * ing the utmost of Luxury, Comfort, \Y Safety and Power } The big Twin Military Model with Excelsior Kushion Sprocket, Double Trussed Military Front Fork, Automatic Compression Control, Entirely i Enclosed: Clutch, and Motor Drive Chain, 1 Cushioned Pinion Motor Starter, Open Bottom | Frame with Removable Center Bar, and other valuable features, all exclusively EXCELSIOR. | Bear in mind. We also build the Excelsior Side Car to fit both Excelsior and Henderson and the Excelsior 1 Lightweight, the safest and most economical motorcycle for general utility ever made. Write for Catalog, or see the Dealer. EXCELSIOR MOTOR, MFG. & SUPPLY CO., *@AfexwS? Atte" How to SAVE When SIG That Buying Auto Supplies I | 3 ed

FREE "cr." ee Te 400-pace FREE Book will be the u upply Show for over Supplies 2 motorists. Contains many

| brand new supplies. Over 2,000 selections } to choose from. Sit in an easy cnair and do your buying. Everythisg from bum- it = per to tail light. Twenty pages exclusively wil 7 tor Ford Owners.. Always refer to it be- fore buying. Write right now for your N FV FREE copy to nearest store, TIRE FLUID The Old Reliable 25%a tube m BUFFALO SPECIALTY CO.BuffaloNY Easy Way to Make Money

Don’t be content to plod along ona small salary. Be independent. Go in the tire repairing business and make $60 or more a week. One man made $45 the first day he received his outfit. Others are making $25 a day and hundreds of wide-awake men are making $200 to $500 a month. No experience needed. We teach you how. Very little capital required. But slight risk, as every car owner in your town is a possible customer. Jobs are plentiful . because tires blow out and puncture every day. OHA ALER Tire Repair Outtit, $7 Oo vulcanizing outfits. A boy can vulcanize perfectly with this simple machine. It’s the only vulcanizer that has Automatic Heat Control. It must vulcanize just right. It can’t undercure or —— a “ — gto or regulating. You can‘ i canizing in half an hour with the aler. WHITE FOR FREE BOOK "so" 72 sit are ssrain snore and complete Catalog, which gives full information. WRITE QUICK BEFORE SOME HUSTLER GETS AHEAD OF YOt ‘ U. C. A. SHALER CO., 2105 Fourth Street, WAUPUN, WIS. When writing to Advertisers please mention Popular Science Monthly

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Why Corbin Control Means Safety Assured Relative sizes of % inch ball (as used in Corbin Duplex Brake) and 5/16 and es inch used in oer brakes. En- larged to per- mitt of easy comparison. ‘THE Corbin Duplex bicycle brake is built oversize at every point where strain or wear is to be expected. An excellent proof is found in the size of the balls used. This oversize policy is expensive for the -manufacturer, but the best for you. It guarantees safety, comfort and long wear. The bicycle, because of its economy and great utility, stands higher than ever before in the esteem of the nation, and the Corbin Duplex brake has helped t= place it in that position. In ordinary service slight pressure stops your bicycle slowly; in an emergency, harder pressure stops it instantly. All riders who use their bicycles for every- day business or pleasure service need the When purchasing a bi- Corbin Duplex. cycle specifying the Corbin. Write for Catalog CORBIN SCREW CORPORATION American Hardware Corporation, Successor 202 High Street, Branches: New York . i Chicago Popular Science Monthly New Britain, Conn. Philadelphia When writing to Advertisers please mention Popular Science Monthly 3 Build and Fly Mode 2 x War Aeroplanes! Planse and hee thea *panout Aery. a hae Piece {dopiicates zis a ee P dye —_ ‘OU W: wines 7% Curtiss oe Kictinore an ant ne epee dg mee toe ube Mon iss "tiyine, Boat, Curtion’s R Beotr ac vad. ight Surtiss Hinde a Compl. , Set of Eight. $1.75, ig Get our lat Mode ‘ ‘Aeroplanes, Parts, Meterials. Supplies. 60 p = SHES On Ou pages. IDEAL Ae ROPLANE & SUPPLY CO., 80-86 WEST BROA Dway. NEW a Print Y Cards, qu Orn Programs, Circulars, Book, Paper, With an Excelsio receipts, CUTS your EX PENGHA Joe ‘g use, printed rules sent. Boy can do work. SMALL OUTLAY, pays for itse fin ashort time. Will last for r years, vite factory -TO-DAY Boel onion. of p the’ an outfit, sam RESS CO. 0-33, MERIDEN "eo , SAVE 25% to 60% on slightly used GRAFLEX-KOD Wir 4 Cameras and Lenses ot every description. Equal to neg, Save money. Write now for y Free Bargain Book and Catal listing hundreds of money-saving bargains in slignly fae used and new cameras and supplies. All goods soldes ’ = 10 days’ Free Trial. Money back if not satisfied. You take no chances dealing with us. We have been in the photographic business over 16 years. Write now, CENTRAL CAMERA CO, Dept. 56, 124 S. Wabash Ave., Chicags : Md Figure it out for Big Profits in Charging yourself. ‘This 500 4 a ery Auto Storage Batteries & Charger will re-| charge 1 to 7 batteries at a time. Current costs oniy 12c to 15c per battery. Autoist pays 75¢ to $1.50. Your ur profit j is 60c to $1.35 on every battery { ou charge. er HB owners are making $40 to 360 and more b mes profit every month. So can you. F $15 Puts this Money-Maker in Your Garage @ Balance in 9 monthly payments of “sey each, which earnings should easily pay. Write ~=* a Particulars or send $15 first payment with uso lo risk. Absolute money-back guarant HOBART BROTHERS CO., Bor 6S, Troy, Ohio, © AGENTS a. PROFI Gold and Silver Sign Letters For store fronts, office windows and glass signs of a sinds. No experience necessary. Anyone can pat them on and make money right from the start. $30.00 to $100.00 a Week! You can sell to nearby trade or travel all over the country. There is a big demand for window lettering in every town. Send for Free Sample and full particulars. Liberal Offer to General Agents. METALLIC LETTER CO., 400 N. Clark St., Chicage er. opportunities for Guita> 3 eith i locali' pa I ei 0 BUSINESS ON OUR CAPITAL sil Recricry ae = Stock furnished. yey goods a shen oa return ; SS i Hunt. to those oes 101 ; -00 book ‘‘The Organiza‘ Organization, , and tenance of director, Wm. Place, Jr. Practice, Psychologically FREE. Cet talog, Treatise frente, Ue 4 obec reasaenialy Sets Oat eo TT

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13 Sasge * is 13 «fee SEF ssress! MQ be Las ome I OO ee PITENTS IF YOU HAVE AN INVENTION which you wish to patent you can write fully and freely to Munn & Co. for advice in regard to the best way of obtaining protection. Please send sketches or a model of your inven- tion and a description of the device, explaining its operation. All patents secured by us are described in SCIENTIFIC AMERICAN : without cost to patentee All communications are strictly confiden- tial. Our vast practice, extending over a period of seventy years, enables us in many cases to advise in regard to patent- ability without any expense to the client. Our Hand-Book on Patents is sent free on request. This explains our methods, terms, etc., in regards to Patents, Trade Marks, Foreign Patents, etc. MUNN & Co. SOLICITORS OF PATENTS 683 WOOLWORTH BLDG., NEW YORK and 627 F STREET, WASHINGTON, D. C. Popular Science Monthly 129 We furnish Edwards complete locke Sse ge css germina te. ° Edwardes Steel Lock- h hat shelves, locks and num- ijustable, econe hooks, lockin ey te aes semen Eerie Es : I Lockers c' id in bs ced enamel. Send catalog and estimates. Responsibi d for unoc- terms. cupied pablichod Write for special The Edwards Mfg. Co., 307-357 Culvert St., Cincinnati, O. gp “The RAZOR thal mokes APD K SHAVINGA PLEASURE WARS TH this new Electrical Wonder you get the pleasant effect of a massage anda shave at the same time. . This razor is on the market and we are shipping to all points in the United States and South America. This device can be used without electricity like the ordi- nary safety razors, but is supposed to be used with alter- Nating current. The blade moves 7200 times per minute and actually cuts the hair without pulling. Price, $10.00. Vibrating Electric Razor Co., Omaha, Neb. Makers Edwards Adjustable All-Stee! Shetving Post Offices, oo ey Fe er pt ee HE Pushing Machines to Produce at War-speed You have to know when to push a machine if you’re going to run it for all it’s worth to the nation and to your own business. So you'll know just what your ma- chines should produce—so you'll hold their output to the service limit—is the urgent reason today for using COUNTERS The Revolution Counter below registers one for each revolution of a shaft, recording a machine-operation. The mechanism of this counter will stand continu- ous high speed, which — it especially suit- able for experi- mental work in developing, as well as operat- ing machinery. Will subtract if run back- ward. Price, $1.50. Where a back-and-forth thrust registers an operation, where you're counting the output of punch-presses or similar machines, use the Set-Back Rotary Ratchet Counter below. Set back to zero by turning knob, and supplied with from 4 to 10 figure- wheels, as required. Price, with 4 wheels, $9.50 (list), ecdicdicdae | Perhaps you'd like to see counters for other purposes than the above; they're ali in our booklet—send your name for a copy. THE VEEDER MFG. CO. 44 SARGEANT ST., HARTFORD, CONN.) When writing to Advertisers please mention Popular Science Monthly

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abili ling inte corporation. million dollars. better than Correspondence Schools. now hold. The I. ee ng go ENGINEER Wi Telegraph Engineer Telephone Work MEOHANIOAL ENGINEER lechanical Machine Shop Practice Gas Engine Gperstiog OIVIL ENGINEER Surveying and Mapping MINE FOREMAN OR ENGINEER Metallurgist or pector STATIONARY ENGINEER — Engineer Contractcr and Builder Architecturai Draftsman ral Concrete Builder Structural Engineer PLUMBING AND HEATING Sheet Metal Worker Textile _— or Supt. Zz F .the bottom and work his wa ago Eugene Grace was switching engines. His to out-ihink his job, coupled with his ster- grity, lifted him to the presidency of our Last year he earned more than a . . « . Jimmie Ward, one of our vice-presidents, used to be a stenographer. The fifteen men in charge of the plants were selected, not because of some startling stroke of genius, but because day in and day out, thiey were thinking beyond their jobs.’’ _ “There is not a man in power at the Bethlehem Steel Works today,’’ says Charles M. Schwab, in the American Magazine, “who did not begin at up. Eight years If you want to be somebody, to climb to a position of re- sponsibility, get ready for it. Do what you are doing now e men beside you, and train for the job ahead. You can do it—in_ spare time—through the International For 25 years men with ambition and I. C.S. help have been making spare hours the stepping-stones to successful careers. Last year more than 5,000 ‘ studies had won for them advancement and increased sal- aries. Over 130,000 men in offices, shops, stores, mines and mills and on railroads all over America are preparing in the I. C. S. way to take the next step upward. Join them! All you need is just ordinary brains, the will to do, and the firm resolve to think ahead of the job you C. S. are ready to make the rest easy. Make your start. Mark and mail this coupon. CNTERNATIONAL TEAR OUT HERE NTERNATIONAL CORRESPONDENCE SCHOOLS BOX 5881, SCRANTON, PA. Explain, without obligating me, how I can qualify for the posi- tion, or in the subject, before which I mark X. reported that their SALESMANSHIP ADVERTISING Window Trimmer Show Card Writer Sign Painter Railroad Trainman ILLUSTRATING Cartooning BOOKKEEPER Stenographer and Typist Cert. Public Accountant TRAFFIC MANAGER Railway Accountant Commercial Law GOOD ENGLISH Teacher Common School Subjects Mathematics CIVIL SERVICE Railway Mail Clerk AUTOMOBILE OPERATING Auto Repairing Spanish Navigation German AGRICULTURE French Poultry Raising Italian tog iff z ) & & State__... ieee When writing to Advertisers please mention Popular Science Monthly} Popular Science Monthly y Pay Full Prices IAMOND Bankin . of a million dollar Oat gy business We lend money, ti: diamonég, etc., as security, n ™ unpaid we must sel) to get our mon amazing bargains proved 7 Most | ters. Diamonds, Rings, Pann” i) ants. sete at prices we c you te | matc! per cent moi abso- (j lutely free examination. bei. Write for JOS. DeRoy Bulletia Send your name today and we will send you our of bargains showing | bundreds of unpaid Png 4 absolutely free. . PITTSBURG, A,” “DON'T SHOUT” “Tl hear you. I can hear now as well as anybody. ‘How?’ With 3 THE MORLEY PHONE. My I’ve a pair in my ears now, but they are invisible. I would not know I had them in, myself, only that I hear all right. / “The Morley Phone for the DEAF is to the ears what glasses | are to the eyes. Invisible, comfortable, weightless and harmless. Anyone can adjust it.” Over one hundred thousand sold. Write for booklet and testimonish, THE MORLEY CO., Dept. 797, Perry Bldg., Phila, Turns night into day. 300 candle power. Carry as a lantern; use anywhere as a lamp. Weather proof. For house, barn, camp and around the farm. Write for new Gnd mooriss. Agents mote dig’ may ae 01 ; gents ma tonight for new 1918 offer. . ; 238 ACORN BLDG... Cliche Cian Get this UP-TO-DATE combi tion clasp and hap : vents loss of pen or cig ®, ek] be W/ State for Pen or Pencil ARGUS 402-406 N. P. } Brooks’ Appliance, the moder ai —_ Peon Fee wonder: ww AO new discovery that relieves ieee! rupture will be sent on trial, No obnoxious springs or pads. Brooks’ Rupture Appliance Has automatic Air Cushions. Binds and draws broken parts together as you would a broken a ee Oe sis Carslopue and Beams i y U.S. patents. alogue a bianks mailed free. Send name and address today. Mich, C. E. BROOKS, 255 State St., Marshall, G@wadt 2.22 “2344 THeerFs at , a SE) || & ET | wat ener EE

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\ "WAY UNDER MAN FACTURER’S PRICE? tencil Attachment, 2-color Rennes Waterproof Cover and_ Speci Touch Typeentting Gude / Guide ee sent on 10 Days’ $09,000 | \ Underwoods Said to U.S. Govt. t Under- That makes rebuilt Uni ‘ok rent, buy on easy terms, cots discount or earn one Jan; no canvas= - on "No. PORIUM

it You Want an Electrical Book and don’t know ere to get it, write Book Department, Popular Science ionthly, 225 West 39th Street, New York City. [TYPEWRITERS $10 and up. All makes. Save $25 to $50 on rebuilt at the factory by the well-known “Young Process.’ Sold for low cash— installment or rented. Rental applies on purchase price. Write for full details and guarantee. Free trial. YOUNG TYPEWRITER CO., Dept. 277, Chicago $ . |Adding Machine goghaaa {\ ewe

For Personal Desk or General Office iy It checks mentalcalculations [if Buy through your stationer {f § Writefor 10-day Trial Offer Wy P. E. Gancher, A. A. M. Oo. 148 Duane St., New York — Amberola Mr. Edisons?

For Our New re aay Boo! ‘or our beh ae an Edison Amberolas. No‘sbiigation a—write while this offer lasts. : F. K. BABSON. Edison Rank Distributors Popular Science Monthly

bw A120 Edison Block, Chicago, Winols 1

When writing to Advertisers please mention Popular Science Monthly You can now afford to wear (}]GenuineDIAMONDS at Bar nard Impax ty

tells you all you want to know about diamonds— = am| howto buy them,safely and intelligently —whydiamondsaretheworld’sbest investment—how I save you 35% by direct importing and eliminat- ing all middlemen—how because my business comes from all over the world, I can succeed in spite of small profits—how I can afford raara tO Sell mountings at factory cost —how I offer diamonds in seven qualities and all carat sizes, so that you can now afford to wear genuine diamonds at my less than wholesale price. Send No Money! You take no risk under my free examination plan. Just select your diamond and favorite setting from my book and I will ship it sothat you can examine it with- out the slightest obligation to buy. My costly De Luxe Book of Diamondsshowsthe world’smost sensational dia- mond bargainsand I back them with the only Bankable Money-Back GUARANTEE Issued only by Barnard— Diamond Headquarters permits you to cash in your diamond investment within one year and to exchangeat full value at any time. written legal certificate of carat weight, color and value.

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Why the Dayton Lasts so Long DAYTON Bicycles out-live the ordinary bicycle because of sup- erior design, better material and extra care in every detail of con- struction. We know of twenty- three-year-old DAYTON Br- cycLes—still in service! ‘Dayton Bicycles are made, throughout, of the best materials obtainable for the purpose, Drop- forgings and inner reinforcements play an important part in the long life ofa Dayton! Construction methods and design are also important. DAYTONS are both designed and éSui/t to last. WRITE FOR FREE CATALOG Gives all Dayton details and tells how to make money and save time with a bicycle. Cycle Dept. The Davis SEwING MACHINE Co, Dayton, Oxn10 DAYTON FEATURES— Cones carbonized,then case- hardenedincyanide. Extra large, High Duty ( AA) ball bearings. 2-Point Bearings, front and rear. Front hub and cup turned from solid steel.One-piece drop-forged crank. See other features in Ad No.6 ] Popular Science Monthly Fullest Pleasure from Your L When writing to Advertisers please mention Popular Science Monthly Boating Convert your row-boat or canoe Send for this book. It tells you how. And it bristles with valuable en- 4 information, MARINE €Q ENGINES 204 Cyclke~2 0200 Portable, easily- at- tachable, ¥f outboard engines afford the joys of motor boating at little cost. A generous 30 Days’ Trial lets you try out ¥Yf En-. gines at our expense. LOCK WOOD-ASH MOTOR CO. 1851 Horton Ave. Jackson Mich. into a power- boat! ~ ‘When they equip their guns with the Maxim Silencer. It elimi- nates the =". entirety. No tiinch- ing, no recoli, no “nerves. —— . ons practice nok gees small gun shoot- ting pastime for the whole family. MAXIM SILENCE fits any rifle. The price is reasonable. Ask at your dealer’s, and write us for free book of peculiar experiences of Maxim Silencer users. @ THE MAXIM SILENCER CO., 91 Homestead Ave., Hartford, Conn. C & You Who Cannot Go, Do: Your “Bayonet Exercise” with a “Bristol” should not keep yourself in “fit” condition to carry the extra load of work and worry “‘over here.” Bristol- Steel Fishing Rods AND MEEK REELS Ever try fishing? Great exercise and recreation. Just out. Send for it today. FREE. THE HORTON MFG. CO., “i 197 Horton Street Many of you for business or professional reasons } cannot go ‘‘over there.”’ But that 1 is no reason why you | 1 NEW “BRISTOL”- MEEK CATALOGUE FREE } Bristol, Cone. . Sp ru Eq 3 = 2) a IUTUUNNOTNCGTOOTVOT uty av tenes UaNeNAUAARANSRE HU UMENARSUNOU UMMM DDR RRN PANT RRNA ANT HT HEUTE

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AUER ETOOUVOTIVGUTONTEOHY ensNnN0taneanrUyaUasnesrMMRERSUAT HAMM MEMUNENANRR ENR UC ONT ATN NTA RANA RENE UAT ’

“He’s After It!” ’S a big fellow, by the feel of him. Let him run awhile—then strike him hard! Fishing’s great sport, isn’t it?—especially when you have an EVINRUDE DETACHABLE ROWBOAT & CANOE MOTOR peci ethod of balancing gives the 1918 Evin- Bos eee tally smooth, vibrationless running. Equipped with Evinrude Magneto—Built-In Fly- wheel Type and Automatic Reverse. New catalog just out—write for it. EVINRUDE MOTOR CO. 855 Evinrude Block * Milwaukee, Wis. ranches: k, Boston, San Francisco, Portland, Ore. ew Ter Toronto, Montreal, Victoria Also Manufacturers of The Evinrude Oil Engine "Evinruding— Ls, Rowboat Motoring IMM MMMM MMMM MMT Popular Science Monthly ATTUNED MLD ULL UU PUTT. => => = = = =

“ay to Diane cteititiagee hata to be out on the water in a staunch, speedy Old Town, the master canoe! unshine, stimulating air and invigor- atingexercise. What Doctor can write a better HEALTH prescription? Old Town Canoes are graceful, buoyant and beautifully balanced. Like a flash they respond to each stroke. Let an Old Town carry you far and near, for an all day paddle ora short run to a near-by cove anda hearty picnic lunch. Write 4 today for catalog which also illustrates the “Sponson Model,” the safest canoe in the world. OLD TOWN CANOE CO. 1796 Main St.

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Here is THE electrica: magazine for you. For the Dabbler and the ‘‘How- to-make-it”’ fiend. Chuck full of experiments and the latest electrical do- ings. Non-technical—in plain English. One of the foremost authorities on WIRELESS in U.S. 200 Illustrations, 90 big pages. Over 100 articles. One copy will convince you At All News Stands 15c $1.50 a year, (Foreign $2.00) Send 25c for 3 numbers The Electrical Experimenter J 235 Fulton St., New York GseElectrical Experimenter TELEVISION THE TELEPHOT

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Send for Our New Edition of Our Catalog A28 It will be pocket size, 8x 41% and will contain 248 noe with over 1,100 illustra- tions, describing in plain, clear language all about Bells, Telephone and Telegraph Material, Electric Toys, Burglar and Fire Alarm Con- trivances, Electric Call Bells, Electric Alarm Clocks, Medical Batteries, Motor Boat Horns, Electrically Heated Apparatus, Battery Gauges, Wireless Telegraph Instruments, Ignition Supplies, etc. MANHATTAN ELECTRICAL SUPPLY COMPANY, Inc. Push Buttons, Batteries, Battery Connectors, Switches,

ST. LOUIS, 1106 Pine St. SAN FRANCISCO, 604 Mission St.

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! ‘o ip Overt WALTHAM ELGIN HOWARD ROCKFORD ILLINOIS HAMILTON the people. That is why I am doing the greateSt credit Watch, Dia- | Sl Any Watc roy 2 an OA 2 4B) fe 8 One Customer Writes: says its the best time kee **T have had my watch just @ year today and our watch per on the road. Please find enclosed my last monthly payment of $1.00.’ We have thousands of such letters on file from satisfied customers, who have bought from us on 30 Days Trial Nefoney Down You take no chances with me. I am‘ Square Deal’’ Miller and I trust and Jewelry business in the world. Watches Guaranteed for 25 Years I] Smash the Terms NO REFERENCES DEMANDED terms will surely suit you. You get unlimited credit. A Charge ACCOUNE the same kind of credit you get from your grocer No matter where you live or what your income might be, you can now own the finest of watches, 8 beautiful diamond or any rare jewelry and never miss the money. talog FREE Send me your name and address so I can mail you Free and postpaid the most beautiful catalog of its kind ever printed. I want you to have this book. It’s a gem. Write TODAY. A SQUARE DEAL MILLER, Pres. 1033 Miller Bldg., Detroit, Mich. et Cash er Real Estate Any kind. Anywhere. The Simplex Plans will show you how. No commission to pay. Valuable information FREE. SIMPLEX, Dept. 89 1123 Broadway, New York SEND US YOUR NEXT PHOTO or negatives for Development, Printing or Enlarging by our new, prompt, perfect system. Low prices. Sample Roll developed 10 cents. Send name for details. Roanoke Photo Finishing Co., 213 Bell Ave., Roanoke, Va. WUeLIZER , “= Play It = Pay the violins shown in our new catalog will be sent to you on trial, After you have played on it for a full week, at our expense, you may either rcturn it, or pay the low roc'-bot- tom price in small monthly payments. Trial costs you nothing. id f y WRITE TODAY £224 zezt name and, address for ont w catalog today. See for the violins fron which you have to choose. ‘No obligations. " THE RUDOLPH WURLITZER COMPANY, Dept. A-120 South Wabash Avenue, Chicago East Fourth Street, Cincinnati ———_—__———————— Popular Science Monthly | When writing to Advertisers please mention Popular Science Monthly Big Money in Electricity The electrical industries offer wonderful oppor- tunities to boys with a liking for Electricity. The salaries paid to traincd men are large, promotion comes rapidly and, best of all, the work is fascinating. The discovery and development of new lines (sach as wireless telegraphy and telephony), from time to time, promise attractive and paying fields to those who wish to specialize. The will to do and Special Training will bring success to you. The International Correspondence Schools can help you to become an expert in electrical work, no matter what branch you like best. ‘Thousands of young men havealready won success through I.C.S. help. Youcan doaswellasanybody, ifyou try. Everything is madeso clear that you can learn in your spare time, regardless of where you live or what your work. No books to buy. There’s big money in Electricity. Get after it by marking and mailing the Coupon today. Finding out costs you nothing. —— ot ome em eesTEAR OUT HER Ease pues mee see eee oe oe i j INTERNATIONAL GORRESPONDENGE SCHOOLS Box 5883 SCRANTON, PA. | Explain, without obligating me, how I can qualify for the posi- tion, or in the subject, before which I mark X. ENGINEER CHEMICAL ENGINEER Window Trimmer Show Card Writer Outd ,or Sign Painter RAILROADER T | ILLUSTRATOR DESIGNER ‘elephony BOOKKEEPER | Stenographer and Typist Cert. Public Accountant Railway Accountant Commercial Law GOOD GLISH | Common School Subjects CIVIL SERVICE Railway Mail Clerk Textile Overseer or Su AGRICULTURE [8p ; Draftsm Navigator Germae PLUMBING AND HEATING Poultry Raising French | Sheet Metal Worker Automobiles Italian | Name Present | Occupation Street | and No. | City. State If name of Course you want is not in this list, write it beiow.

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ss ee! — \\ \Ku. | | | | | | Popular Science Monthly AMERICA: NEE | YOUR IDEAS\ Millions of Dollars are being spent RIGHT NOW for inventions of all kinds. for new ideas been so insistent—or so profitable to the Never before has the demand man who will use his brains. Never, during the years I have efficiently served thousands of clients throughout this country and foreign lands, have so many manufacturers and other patent buyers written me asking for good things PROTECTED BY OWEN PATENTS. There is a market for thousands of ideas. YOURS may be one of them. Send for my free books and see for yourself—read the requests for inventions protected by me. These Four Books Free! SUCCESSFUL PATENTS—a 72-page guide to suc- cess, tells how to proceed, etc. STEPPING STONES—zives hundreds of hints of ideas wanted, tells truth about prizes for inventions, etc. PATENT BUYERS mtains over 400 seGnente of manufacturers and others whowant OWEN PATENTS, together with ideas they want. PATENT PROMOTION —tells how to sell, why some - inventors fail, etc. Pll Help You Without Charge to sell your idea by advertising it in ‘Invention and Manufacturing’, putting you in touch with prospective buyers, etc. Send sketch or model for free opinion as to patentability, practicability, cost of Patent, etc. Your work will receive my personal super- vision. Write today for my books. A postal request will do. I'll send you a contract that will give you immediate protection. RICHARD B. OWEN, Patent Lawyer 6 OWEN BLDG., WASHINGTON, D. C. 2276D WOOLWORTH BLDG., NEW YORK CITY CAN YOU think of a simple, practical idea that will fill one of the many re- quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed RIGHT Now. Your brains can help. Send to- day for our great new book—“‘Inventions and Trade Marks, Their Protection and Exploitation’”’ and learn more about-making money from ideas than you ever knew before. It tells many things that are wanted, too. A postal will do— it is free. Read We help our clients, Invention without charge, to get and the dollars out of their ° ideas—having facilities Manufacturing none others possess. __ Advice free. ; oa best yey get ’ or the man who likes to _ ae at Seay art the “dabble’’ with mechanics, ' , electricity, chemistry. AMERICAN aeronautics. 10c a copy from your news dealer. Send us 25c for 3 num- bers. Better still, a $1 bill for a year’s subscription —12 issues. INDUSTRIES, INC. 201 Patent Dept., WASHINGTON, D.C. ‘Inventions Wanted! ufacturers c ta writin: for patewne. List of a cy requested and book “‘How to Obtain a Pat- ent”? sent free. Send rough sketch for free ge ag Write for details of interest to evers inventor, Chandlee & Chandlee, Patent Attorneys Est. 21 Years 563 7thSt.,Washington,D.C., C. L. PARKER 3 Formerly — > Pat ¢ Office, aten: PATENT LAWYER McGill Bi WASHINGTON, D.G Patents, Trade Marks, Copyrights, Patent Litigation Pamphlet of Instructions pon Reavest Protective Patents— procured promptly. Strictly professional ser- vice. No fee refund, no certificate guarantee no so-called prize or free search schemes used in our business. Inventor’s 104 page Blue Book on Patents sent on request. ROBB & ROBB, 240- 244 Southern Building, Washington,D. C. PATENTS ON EASY PAYMENTS Send model or sketch for Free Search and opinion as to patentability. Write for our free book on Inventions Wanted and How to Obtain Patent on Easy Fee Pay- ments. We furnish our clients with list of patent buyers and assist inventors to sell their patents. HINES & CO. When writing to Advertisers please mention Popular Science Monthly 592a Loan and Trust Bldg., Washington,D.C.

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Popular Science Monthly ATENTS ners COPYR IGHTS LIN THE WORLD he SPECIAL OFFER J "Fre Opinion as to Patentability Before sending your invention to any attorney or man- ufacturer or disclosing your invention, write for our free blank form PROOF OF CONCEPTION in order to protect your invention and secure yo..r rights. This should be signed and witnessed and returned to us, together with .a.model oresketch.and.-deseription : of your invention, and we will give a FREE OPINION as to the patentability of the invention. If we report the invention patentable we will furnish a Certificate of Patentability. This Certificate of Patentability, together with our blank form Proof of Conception will protect the inventor and serve as proof of the invention until the case can be’ filed in the U. S. Patent Office Obtaining Assistance for Inventors—Our certificate is of great assistance to inventors who require financial aid to obtain patents. OUR FIVE BOOKS MAILED FREE (See Coupon Below) to any address. Send for these books—the finest publications ever issued for free distribution. gi ~

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VICTOR J. EVANS How to Obtain a Patent List of Patent Buyers Our illustrated eighty-page Guide Contains requests from manufactur- Book is a book of reference for invent- ers, mail order houses and promoters ors and contains 100 mechanical move- for patents secured by us and sugges- ments, illustrated and described. Tells tions as to New Ideas they wish to pur- how to invent for profit. . ae —_ eyed clients in touch with capital free of charge. We have What to Invent recently received over 300 requests Contains a valuable list of inven- from manufacturers. tions wanted se ee age ing profitable fields of inventions; also e information regarding prizes offered Foreign P. atents for inventions amounting to beste a agencies in all the principal foreign countries and secure One Million Dollars —— erg . the shortest on Wi ; = time and at the lowest cost. rite Millions in Trade Marks for our illustrated Guide Book on Shows the value of Trade-Marks and infor- Foreign Patents, sent free to any mation regarding unfair competition. address.

We Advertise Our Clients’ Inventions Free in a list of Sunday newspapers, in manu- #1 facturers’ journals and in World’s Progress. Sample Copy Free. We save you time and money in securing patents. After the patent is granted we assist you to sell your patent. WANTED NEW IDEAS

Prepare Now to meet the Demands of Industry VICTOR BUILDING ¥ in All Fields for New Ideas and New Inventions. , TO wom i =e CONCERN We are constantly receiving requests from manu- = — at va alee To sepa: facturers who consult us when purchasing pat- : ae NER FULLY UNDERSTANDS THE CONSTRUCTION ents for inventions in all lines. We invite manu- meses a oe facturers and promoters to address our Sales Department regarding the purchase or leasing of N a number of meritorious patents secured by us. FREE COUPON! i 8 ates

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Sa rs a) ‘Alii

ij Hundreds of inventions are sold yearly. help you sell yours without cost. efore gending your inventions to anyone send for } i Gur “‘Blank Form of Disclosure’’ that will Protect Mm you until your application is filed in the Patent |

i ce. i Our book “‘Making Ideas Pay” gives full informa- Mm tion relative to securing Patent Pro’ection. Manu- } Mfacturers are writing us continn.usly for new inventions. Send for Book and Blank Form of Disclosure today. | Prompt service. Best results. | A. M. BUCK & CO., Patent Attorneys 510 Second National Bank Bldg. Washington, D. C. Mail this Coupon i

ad A. M. Buck & Co., 510 2nd Natl Bank Bldg, Wash., D. C. | Please send me free book “Making Ideas Pay’”’ and Blank Form of Disclosure.

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NEW SERVICE INVENTORS I personally report upon prepare and prosecute every case submitted to me, ] give every case my closest personal attention. I do not . entrust your interests to assistants. My personal service on your invention jg of vital advantage to you. This is new efficiency, new romptness in patent service. I report on your case intwodays. No longer than Io days to prepare your case for filing. Send sketch or model for prompt search and report. My FREE Book Free, my new 00-page’ boo! “Patent Knowledge ior 5 ong: A volume of real information on patents. Different from the usual “Circus Stuff.’’ Contains s i information usually not told. Write for this free book today. It will open your eyes. GEORGE P. KIMMEL, Patent Lawyer, 39-F Oriental Bldg., Washington, D. C.

We'll Send You a Lachnite —Just Send Your Name! Don’t senda penny. Just send us your name and address. We'll send ng Lachnite Gem ted in a solid gold ring, prepaid, rie t to your home. When it comes mere'y deposit $3.75 with € ear the r ten full days. Jf you or any of your friend: i FI temond, send Vd back, Your epost raonth until sie 70 has heen bald. "Send your Dame Bow. <pecsiag an Write Today Qihici itises's.) Give ts the size of your finger.

Harold Lachman Co., 12 N. Michigan Ave., Dept. A120CHICAGO

Inven

Competent Patent Service id By a Former Examining Official of the U. S. Patent Office NORMAN T. WHITAKER Lawyer and Engineer 280 Whitaker Bldg., Wash., D.C.

INQUIRIES INVITED

ta) RUNS ON KEROSENE] ‘\ Alcohol or Gas Anywhere ia A most remarkable invention. No electricity, wires or springs. 19J8 improved patented Models. Runs 8 hours for a cent on kerosene. Qui onvenient. Brings genuine comfort and satisfaction. Ideal for the sick. A proved success. 4th season. Increase your efficiency. Every home and office should have one. The Wonder Fan. Two Models. Three Sizes, KEEP COOL. BE WELL Address LAKE BREEZE MOTOR, 581 W. Monroe St., Chicage

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Terms reasonable. Send sketch or model for FREE examination and opinion. BONDED and recommended Patent Lawyer in the Rand-McNally Directory of Bankers and Attorneys, published yd Rand- MeNally & Co., Chicago, Ill. Recommended Patent Attorney in the Bankers Register and special list of se’ lected lawyers a by the Credit Company, Pontiac Building, Chicago, Sharp & Alleman’s Directory of Lawyers and Bankers, published at Philadelphia, and Martindale’s American Legal Directory of New York City. ALL BUSINESS GIVEN PROMPT AND PROPER ATTENTION THAT PROTECT and PAY SEND FOR FREE BOOKS Highest references. Best results.

A large list of strong recommendations furnished free

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chase patents. » -Send+Model or Sketch .and description of your invention for Free Opinion as to patentability ‘‘Special Bulletin of Patent Buyers’”’ This bulletin contains letters from men who are seeking to pur- We act as intermediary without one cent of charge, between the man who invents and the man who invests. Specialty Rejected and D¢tfficult Cases are Our RANDOLPH & CO. 130 F St.,N.W., Washington, D.C. Popuiar Science Monthly Ko Got Co Keres We) Inventors! Send for these Remarkable FREE BOOKS, Today ‘¢ Inventions Needed ’”’ This book lays before you a description of the active and profitable field of invention. It tells you the inventions the world needs today, the devices manufacturers are seeking for their business, the ideas for which the public will pay big money. ‘SHow to Get Your Patent” This book is a guide to the inventor. thing and desire to learn what it will cost you to get your patent and what you must do to find your market, read this book. a RANDOLPH & CO. If you have invented some- 130 F St., N. W., Washington, D.C. Gentlemen: Please send me without obligation on My part, the books indicated on margin of this coupon. books desired.) (Write on margin of coupon, names of Ae Ge Pa i y INVENTOR should have my book *‘PATENTS AND PATENT PUSBILITIES.”” It is full of information concerning opportunities for success in invention. Tells what to invent, how to sell it, and about PATENT POSS Hider fears ASHED IN eye, inventi ? Writ ° iL, 803 McLachien Bidg., WASHINGTON, D. C Dew H. S. HILL, e ToDay for this an F Book. SS mean in PATENT t sta SILITIES ® J PTNES: Your Ideas May Bring Wealth. | Send postal for Free Book—tells What to Invent and How to Obtain a Pate ent through our Credit System. Talbert & Talbert 4621 Talbert Building, Washingt KEEPS” Worth more than all other patent books combined. FREE. Write LACEY & LACEY 121 Springer Bldg., Washington, D.C. Established 1869 on, D. ce. orem cee = “The Book the Inventor vee TATE ANCASTER 7 8. ALLWINE 274 OURAY BLDG., _ WASHINGTON, D. C. Don’t Lose Your Rights We publish fcrm: called “Evid of C ti ” by which you can establish your rights before sending the invention to anyone. It is your best protection. We issue up-to-date bulletins of improvements wanted: aid inven- tors to promote their rights; render reliable opinions free of charge and secure valuable patents and trade marks op i reasonable terms, Guarantee Co Washington, J. ion SIMPLY MAIL COUPO Personal service assured by our ice mtract. References 2nd National Bank, P. Roth Packing Co.. Cincinnati. LANCASTER & ALLWINE, 274 Ouray Bidg., Washington, D. C. Send me free, book ‘‘Inventions—Patenting & Promoting,’ Bulletin of Improvements Wanted and blank form, * vider of Conception.” When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly This is No. 4702 One of 77 different styles of Dayle “Excellent lasting qualities” “The Eldorado pencils are smooth and have excellent last- ing qualities.” Thus writes the Engineer of one of the biggest steel car companies in the country. ELDoRADO the master drawing pencil” is pleasing thousands of big concerns. The leads are smooth, gritless, true to grade in each of the 17 degrees. They are firm and strong and bear unusual . pressure without breaking. Send 16c in stamps for full-length samples worth double the money. JOSEPH DIXON CRUCIBLE COMPANY Dept. 120-J, Jersey City, N. J. When writing to Advertisers please mention Popular Science Monthly —_— V UE!“ M@@«@@ MEE PROFITS From Investments Your investment profits depend on some- thing more than the mere decision to buy stocks or bonds. Any broker can execute orders for securi- ties when you so desire. But it is the knowledge of WHEN and HOW best to buy that makes invest- ments profitable to you. ee SSS Our fortnightly publication Investment Opportunities tells WHEN —and our copyrighted TWENTY PAYMENT BOOKLET tells HOW. Both sent gratis upon’ te quest for 63-PS. CLATTERY@G eee Securities (Founded 1908) 40 Exchange Place XD?P’71F. BBW MG. SNS New York | — ddd EL

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From an original painting in biden first thought of Mr. du Pont was the preservation oils, showing a spot of great re] l-hei is fi igni i Gee ce ike ane and well-being of his fine old trees. In designing great country estate property of Mr. estates or modest country places, there are generally cer- Ireneé du Pont, near Wilming- tain trees around which the whole plan is developed. ton, Delaware Many an owner has located his house, drives and entrance in relation to special trees, only to find, too late, that they were past saving or had been irreparably injured in the execution of the other work. What Mr. du Pont is doing on his estate in assuring the health and safety of the trees first, should be done in every instance. This highly important work was intrusted by Mr. du Pont to the demonstrated skill of Davey Tree Surgeons. Among hundreds of distinguished Davey clients are: Mr. VINCENT ASTOR Sen. CLARENCE W. WA'ISON Mr. J. OGDEN ARMOUR Mr. ISAAC UNTERMEYER Mr. P. A. B. WIDENER Mr. WM. M. WOOD Mrs. JOHN J. ALBRIGHT Hon. JAS. R. GARFIELD JOHN DAVEY A careful examination of your trees will be made by appointment. Father of Tree Surgery DAVEY TREE EXPERT CO., 206 ELM ST., KENT, OHIO Branch Offices, with telephone connections: 225 Fifth Ave., New York; 2017 Land Title Bldg., Philadelphia; 450 McCormick Bldg., Chicago DAVEY TREE SURGEONS WRITE NEAREST OFFICE Permanent representatives located at Boston, Newport, Lenoz, Hartford, Stamford, Albany, Poughkeepsie, White Plains, Jamaica, L. 1., Newark, N. J., Harrisburg, Baltimore, Washington, Buffalo, Pittsburgh, Cleveland, Detroit, Cincinnati, Louisville, Milwaukee, Minneapolis, St. Louis, Kansas City. Canadian address: 22 Victoria Square, Montreal. Every real Davey I'ree Surgeon is in the employ of the Davey Tree Expert Com- pany, and the public is cautioned against those falsely representing themselves

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i The Triumphal March of ; REG US PAT OFF America’s Soft Drink Supreme I Came -1 Saw I Conquered Milk or water may contain bacteria: Bevo never does. Approved for use by the Government and immensely popular in the U: S. Canton- ments and on Men-o’-war. ANHEUSER-BUSCH ST. LOUIS The new eight-million-dollar Bevo bottling and shippi plant—largest in the world, acres floor ity of 2,000,000 y—employment of

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Popular Science Monthly oem ae 7 @ Let Your Aviator Have the Best Send Him the Grinnell Air-Service Mitten “THE ACE”—Best for Aviation Made of highest grade coltskin leather, in either tan, black or khaki. No fancy or unnecessary con- traptions interfere with the service and comfort of this mitten. Has loose “slip in” lining with tight fitting strap fastener. Style 4360. One finger Aviation Mitten made with gauntlet of high grade coltskin in khaki or black. Also supplied in full mittens and gloves. Your aviator will appreciate a pair of these splendid mittens. They will give him extraordinary service because they are carefully made and extremely dur- able. They are washable in soap and water or gasoline and guaranteed not to peel, crack, shrink or harden.: Grinnell Gloves “Best for every purpose” 1918 Book Free Write at once for our new style book, also ourspecial bookletillustrating our ll uss full line of Army and Aviation Gloves. If your dealer does not Styl carry the exact glove you wish give us his name and let us know yte he size you desire. We will send a pair for your inspection. MORRISON-RICKER MFG. CO. = (2 stablished 1856) 142 Broad St., Grinnell, lowa spe a fa ‘‘The Ace’’ 4360 Agents ser | ATES pikEMODEL ===, 50 DAYS Agent in every neighborhood to ride and exhibit the new RANGER.” You can select the parti- cular style suited to your own needs. Boys and young men in all partsof the country areriding ““Rangers’’ ‘| and taking orders from their friends. Our great output, perfected methods = ppetioes: é = it Bierclon at Electrie Light ity” Bicycles at : S o/ prices below all ote and Auto Horn competitors. — =" we GIVEN FREE H 66 +b Colors and Sizes in the famous line of “MEAD” our oi¢e 0 anger y @s Bicycles, shown in full color in our big new Cata- alogue just off thepress. The electric lighted Motorbike, Scout or Superbe models,—the Arch-Frame, Special or Racing Models; girls and ladies models, too. There isa MEAD Bicycle for every rider, at prices made possible only by our FACTOR Y-DIRECT-TO-RIDER sales plan. SEND NO MONE but write TODAY for the new Catalogue of ‘‘Ranger”’ Bicycles, Tires and Sundiies at prices so charges low they will astonish you. Also, full particulars of our great new offer to deliver to you all prepaid your choice of any of the 44 kinds of ‘“‘Ranger’’ Bicycles you may select, for ONE MONTH'S FREE TRIAIL,. This wonderful offer is absolutely genuine. ® TIRE with Coaster-Brakes, Inner Tubes, Electric Lighting Outfits, all the S; LAMPS, Built-u Wheels newest ideas in Bicycle equipment and Sundries, as well as the Repair Parts and Pambination Offers ie gettting one. old gene aenn, fully eptennes, at yA ag me PRICES. be new Cotsloues is larges € ued by any Bicycle concern. Even if_ you do not need a new Bicycle now, ~r P “pair Parts, Tires. . icycle, ¥0u need this Catalogue to tell you the prices you should pay when you do buy. ” P ” ; email | i suai MEAD CYCLE COMPANY. Dent. C-109 : CHICAGO, ILLINOIS When writing to Advertisers please mention Popular Science Monthly

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Popular Science Monthly AeTLLINOIS Zx2$ SantaFeSpecial 50 A JEWEL? MONTH 21 Perfect Jewels Adjusted to Positions Adjusted Write Today Your name ona postal brings the SPECIAL DISTRIBUTION OFFER Right NOW—In the face of advancing prices—this offer is made for distribution purposes. PROFITS ARE SACRIFICED. Buy now before this offer is withdrawn. You can NOW secure a ‘‘Santa Fe Special’? watch on EASY TERMS and at a money saving price, arranged for distribution purposes, in fact, much below present day watch prices. The ‘‘Santa Fe Special” watch is GUAR. ANTEED to pass railroad inspection. You should see the ‘Santa Fe Special’ in order to fully realize the beauty of the newest designs in cases, see the 3-color inlay work and think how distinctive your watch would be with your own name or monogram or an emblem inlaid in the gold case. See the French Art designs in engraved cases or any special emblem or monogram, executed to suit you. Write for the New Watch Book Today A letter or your name on a postal brings the watch book. READ all watch, the “Santa Fe Special.”’ about this , Watch Book SANTA FE WATCH CO., Dept. 6105 - - - Topeka, Kans, or Sac armaacmamenat WATCH PRICES SHATTERED NEW CASE DESIGNS READ our money saving offer. -” buys the — s]AVere iis = Our plan gives you this new model Black Beauty Bicycle ON APPROVAL Factay ,Direct Keep it if you like it—pay small deposit, then $1 a week; or return at our expense. No risk at all. Guaranteed 5 years. \ \ WO Ag . N r brake; e- Best Tires—the famous ; taileolor design; etc, $9.00 VITALIC NON-SKID TIRES W for Pl d big Black Beauty Catalo; R I T E T O D AY dn colors). FREE. Pick out your model. SUNDRIES. —Save money. Get our factory-price. Sundries Catalog. u ts nd lies — everything for cyclists. Bicycle parts, ies a HAVERFORD CYCLE CO., (Est. 22 Yrs.) Dept. G26, PHILADELPHIA 18 Big Features— ** finger ’’’ grips, 12- arm sprocket; ft a small cost, by using our lattachable_ outfit. Fits any Bicycle. Easily attached. No Special tools required. Used His Four Years” flarry A. Hyatt. of Boreas River, New York, writes: ‘“ About four yars ago I received my motor attachment, and wish tosay that Iam satisfied with it in erery way, for it has certainly given me qoud gervice. Anyone wanting a motorcycle or attachment, I would recommend them to the Shaw Manufacturing Co.” FREE BOOK Write today for bargain list and free booklet, fully describing the SHAWRBicycle Motor Attachment. Motor- cycles all makes, newand second-hand, $35.00 up. £. SHAW MANUFACTURING CO. Dept. 169 GALESBURG, KANSAS CONVERT YOUR BICYCLE INTOA } MOTOR-CYCLE Fits a» . 4 wheel. Best hill climber. Most reliable. AN Gils More STEFFEY’S in use thanall others. LOWEST PRICES. Cash or instalments. Agents wanted. Steffey Mfg. Co., Dep’t S., 5025 Brown Street, Phila., Pa. THE MIDGET SLIDE RULE will add, subtract, multiply, divide; solve problems involving even and uneven roots and powers. Also gives the logarithms of numbers and the Sines and Cosines, Tangents and Co- | tangents of all angles. Its operation is very | simple: quickly solves any mathematical prob- lem. Durably made of metal. Adapted forshop and office use. Fits the pocket, 34 inches in diameter. Price with instructions, $1.00, Your money back tf you are not satisfied, GILSON SLIDE RULE CO., NILES, MICH. WE PAY CASH for PLATINUM SCRAP Mercury, contact points, old false teeth. Send us what you have for disposal, no matter how much or how little, and we will remit full market value by return mail. THE MUTUAL SMELTING & REFINING CO. 42 South Front Street - - - Columbus, Ohio PAY FOR THEMS Ct : ‘atriotic et your of your next winter's living. CANNING OUTFITS ELVES CANNING OUTFITS j Be conom Be F nay for most BUTLER Are simple, economical, practical. Operate easier and quicker than old-fashioned methods. Made for home, club or commercial use. Many were disappoin' not getting an outfitlast year. Expect bigger demand this season. Be safe, investigate now. Write wae factory for free catalog and prices. Good for Live ‘Agents ino Territory. Butler Manufacturing Co. 626 Butler Bldg. 882 6th Ave., 8. EB. Kansas City, Mo. Minn. Minneapolis, Send for my Book Strong Arms and For 25c coin or stamps great strength in your shoulders, arms and without any apparatus. Equal to a PROF. ANTHONY BARKER, 127 West 42nd St., Studio 1153, New Y¥ Military Shoulders Illustrated with 20 full-page half-tone cuts, showing exercises that will quickly develop, beautify and gain

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me SS PBS TS TA aw ROSES | Bee: & #FER Popular Science Monthly > a i AR, stl tna INSURE BY MAIL; SAVE 914% Protect yourself and family by takin : POSTAL LIFE INSURANCE COMPANY” policy in the by corresponding directly with th find more satisfactory:than dealin: You save money too, and get « Youcando it e Company which many g through an agent. advantages and benefits that other companies do not or can not give. In the past twelve years 15,000 people have taken insurance by the Postal’s direct method (without agents) and the Com- pany has distributed over $10,000,000—all by mail—and has received many more millions in premiums through the mail. The Postal way is the best way. Write today mentioning Popular Science for June, with date of birth and occupation. POSTAL LIFE INSURANCE COMPANY WM. R. MALONE, President Postal Life Bidg., 511 Fifth Avenue, New York R » $9,500,000 Insurance in force, $40,000,000 FIFTH AVE..COR. 43! ST. Our Health Bureau Safeguards the Health of Policyholders NEW YORK di naemmeaale a The Best Big Seller For big salesmen—men that can sell and organize for sales. LE N= DERSON STEAM VULCANIZER, with its flexible conformation device, and its principle of superheated dry- steam and heat radiation, gives its users easy advantage overall competition, and our method of doing the work saves more than half the usual cost. Sells for $100 less than any other make of equal daily capacity. Lib- erai contract for fit men. Best states still open. Act quickly and get into the Summer drive. Anderson Steam Vulcanizer Co. 13 Columbia Bldg. Indianapolis, Ind. ae Build Your Own Grandfather’s Clock with our help Wg ()if We furnish blue prints, finish- ing material and instructions. Buy the works, dial, weights and pendulum from us at sur- Prisingly low prices. You make a fine profit Luilding artistic locks for your friends. Complete Works $5.00 Others with chimes at all prices Ask for attractive Free Offer CLOCK COMPANY 1663 Ruffner St., Philadelphia, Pa. Less Easily applied , withcotton andis harmless. Tryit. Leaves healthful, beautiful, natural col- or. Send 35¢c, stamps or coins, for special trial bottle today. Toothwhite Laboratories, Dept. 11, Evanston, Chicago Toothwhite Liquid Home Guard Army Bargains Army Officers say: Bannerman’s| arsenals are a Godsend to us."* 20,000 Rifies 200 Machine Guns 5,0v0 Revolvers 100 B-L Field Cannons 5,000,000 Cartrg’s|50 B-L Navy Cannons 300,000 Equipments/50,000 Explosive Shells me 2,500 Tents 25,000 Uniforms (blue) ty 40,000 Knapsacks| 15 Revolving Cannons We have supplied from our lergest In the world stoc« of army auction goods, the U.S. Government, many states end cities with obsolete serviceable rifles, equipments, and uniforms. Gov't auction sale terms, cash with order. Examina- tion and testing at our arsenals. Immediate deliveries. Large illustrated 428 pp. encyclop, catalog mailed, 50c FRANCIS BANNERMAN & SONS 591 B’WAY, N. Y. The “AUTOSNAP”’ is an automatic shutter operating device. The your picture with the group. YOU get the focus, join the group, The “AUTOSNAP” eliminates makin is your picture with the group. a get out of order, weighs but half an ounce, and so simple a child can operate it. Will last a lifetime, and the only shutter operator guaranteed by the manufacturer to operate each and every time. Made in two sizes to operate:— When you use an ‘“‘AUTOSNAP” you include yourself in all group pictures ‘“‘SAUTOSNAP”’ Manufacturing Co., Rochester, N. Y. “AUTOSNAP” enables you to take and let the ‘AUTOSNAP” do the rest. : i two exposures to get the one result, which Saves 50% of your filmand gives you better pictures. Your camera is not complete without one. Eastman Vest Pocket . . . $ By i Any Camera or Kodak having a cable release . a eee $1 .00 POSTPAID TO ANY ADDRESS When writing to Advertisers please mention Popular Science Monthly

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Your Protection For more than 81 years this name plate has been a guaranty of high grade materials,expert workmanship, economy of operation, surplus power, and engine durability. It is your protection as to engine quality and engine price. WITTE “cx” Engines 2 to.22 H.P. Are made in the largest exclusive engine factory in the world, selling direct to user. Standardized construction in all sizes, all parts interchangeable, easy tounder- stand, install, use, operate and own. I can save you $15 to $200, can make immediate y — factory shipment. My new copyrighted book, “How to Judge Engines’’ tells the whole story, FREE on request. Write for it--read it before you buy any engine.-- ED. H. WITTE, Pres. WITTE ENGINE WORKS 2226 Oakland Ave. KANSAS CITY, MO. 2226Empire Bidg. ‘SBURGH, PA. pee Popular Science Monthly Stocks and Dies: Can be adjusted to the variations in the size of fittings. Results are accomplished with less work and time. Can be sharpened without drawing the temper The Dies are interchangeable in the stocks. Have You a Set in Your Kit? Our catalog tells the rest of this interesting story, send for it to-day. THE ARMSTRONG MFG. CO. 337 Knowlton Street - Bridgeport, Conn. Some of the advantages of Genuine ARMSTRONG When writing to Advertisers please mention Popular Science Monthly AMONDS J ATCHES 14 Low Prices Our Diamonds are distinct; beauty and brilliancy. A Genuine mond is the best investment into which poo can put your money. Withs i leading cities and our extensive Mail Or. der House, our large purchasing power puts us in position to make prices which areimpossible for small concernsto meet, The Handsome Solid Gold La Valliere No.925,hereshown, is our big ] beautiful perfect cut Genuine Dine TERMS: $5 $25 "Sisoemoon™ Send for Free Catalog There are over 2,000 illustrations of Diamonds, Watches, Jewelry, ete Whatever you select will be sent, alj shipping charges prepaid, =m You see and examine the article ; — ” wd own a, as if satisfied, pay one-fift! re price and keep it; balance Siveea eight equal amounts, payable monthly. Our Catalog shows,all the new watches —15, 17, 19, 21, 23 Jewels, adjusted. Guar. anteed by the factory and further guar. anteed by us. Watches that pass rail. Ha road inspection as low as $2 50 a month, Every article in our Catalog is special- & ly selected and priced direct to you, LOFTIS BROS. & CO, | THE NATIONAL CREDIT JEWELERS @ Dept. A871, 108 N State St.,Chicago [lL Stores IN LEADING Cities ASBESTOS We are miners and shippers of Crude Asbestos in any quantity. We produce all gradesjat our world famous BELL ASBESTOS MINES, in Canada, We also card fibres, spin yarns, weave_cloths, and make all sorts of Asbestos products. For anything you want: in Asbestos, turn to KEASBEY & MATTISON COMPANY, Dept. S-4, AMBLER, PENNA., U.S, A, Owners of the world’s largest Asbestos Mines. ~ $3 Cash with order buys this BENCH LATHE Swing 3 in. 8in. C. to C. Skipping Wt. 10 Lbs, Peter Austin, 910 W. First PS., Muncie,ind. Z=POAPR > soz wmowo Tool Cases for Machinists and Tool Makers, none better; sever teen styles. Quartered oak and covered. Ask for booklet, ‘Built for Service.” Sv'anton, Ohio ; ' 4 j i ™— ez od ©. —" In sD Ret DO FOO we A LL) B bee. | | 22

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vs weet id a. Pings tes mee WIRING Popular Science Monthly “Electric Light and Motor Wiring” Here is a book that describes in detail just what the different systems are, how they are installed, and the National Electrical Code requirements regarding them. It is illustrated with photographs and designs. The contents include: Accessories and Fit- tings, Alternators and Generators; Armored Conductor or Cable, Attachment Plugs, Basement Wiring, Bending of Conduit, Cal- culation of Wire Sizes; Cleat Wiring System; Commutators; Conduits; Fittings and Acces- sories; Flexible Tubing; Floor Receptacles; Fuses; Hydraulic Information; Knob Wiring; Lightning Arresters; Metal Moulding; Motors and Their Installation; Open Wiring Systems; Plaster Tubes; Service Connections; Sign Con- struction; Sign Lighting; Sockets; Switches; Transformers. - - - $1.00 Postpaid. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York + | Tool vel: 1 oak oklet, Electricity LEARN FROM THESE BOOKS— THEY ARE WHAT YOU WANT. Arithmetic of Electricity—A practical treatise on electrical calculations of all kinds reduced to a series of rules. $1.00 Postpaid. Armature and Magnet Winding. By Horstmann & Tousley. $1.50 Postpaid. Electricity Made Simple. A book devoid of technicalities. Simple, plain and understandable. $1.00 Postpaid. The Boy Electrician. Practical Plans of Electrical Apparatus for Work and Play with an Explanation of the Principles of Every-day Electricity. $2.00 Postpaid. Construction of Induction Coils and Transformers. Induction coils, inter- rupters, spark gaps, high frequency coils, Tesla coils and high tension transformers. 25e. Postpaid. POPULAR SCIENCE MONTHLY, 225 West 39th Street, New York. FROM THE DIAMOND CUTTERS DIRECT TO YOU BY MAIL AT THE DIAMOND CUTTER'S PRICES 2 blue-white diamonds. Per pair.............. $10.00: A128 $25.00 $39.00. A126 4K wg 16 ‘carat - 14K. cluster platinum diamo: top. 7 blue-white dia- inds.C. A125 $8.95 Solid Gold laval- Ean gad ie. 3 yonds $8.95 A129 $16.75 14K ladies’ peltoace $57.50%% ‘ ‘A130 14K man’s sol- itaire. - 34-carat dia- mo Complete $57.50 Aes rat Ties | $25. solitaire. 34-carat ‘AI31. 14K cluster diamond, C i ‘cach pin. ste er seas 35 MK indies Complete, $25.00 oe joe Com- 5 FREE EXAMINATION— NO ‘OBLIGATION To convince you beyond the shadow of a doubt that our values are absolutely unequalled, we will gladly forward you any article from this ad or from our Catalog, care of your bank or express office, for your examination and approval. We prepay all charges. YOUR MONEY BACK IN FULL ANY TIME WITHIN ONE YEAR Our ironclad guarantee gives you the right to return the diamond to us any time within one year and we give you back the full price you paid without even one cent being deducted. ‘This guarantee is final evidence of the superior values we offer. BIG 1918 CATALOG FREE This remarkable book is a wonderful guide to the selection of gifts for all occasions. It contains 244 pages of intensely interest- ing and valuable information written by recognized experts on Diamonds, Watches, Jewelry, etc., and quotes — of money- saving prices. Write us a letter or postcard for this book NOW. We will mail you, postpaid, a beauti- { ful Red, White and Blue og Flag Button with our Catalog, free, ss ¥3 this Sol f RE ES No Sé SON . @ melt Ww SOLE SALE JEWELER MON DY S 0 E CHESTNUT ST. PHILADELPHIA, U.S.A. When writing to Advertisers please mention Popular Science Monthly

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1id Stock ia Rolled "i Machine Stee ess Liver 18 G86 —_ are whose gives ® Tumbers above THEL.S.ST HE WORLD'S CF The Standardization of Hack Saw Practice by Starrett An enormous reduction in hack saw waste is now possible through the use of the Starrett Chart, which tells you just what saw to use in hand frame or machine to get absolutely the best results on every kind of metal. An indispensable help to every Starrett Hack Saw user—and the reason why every hack saw user should use Starretts. By the chart it is easily possible to select a saw that will give from 25 to 100 per cent more in cutting power or endurance than one not suited for the job. Send immediately for this most helpful chart. Sent FREE. Ask for Chart W. The L. S. Starrett Co. The.World’s Greatest Toolmakers Manufacturers of Hack Saws Unexcelled ATHOL. MASS. Popular Science Monthly When writing to Advertisers please mention Popular Science Monthly tanle . fools “Hurwood” Small Shank Screw Drivers The blades are made of very small stock and the tapered tips of a propor- tionate size. They are exceptionally strong, having the same features as the well known regular ‘‘Hurwood”’ Screw Drivers but with insulated heads. Made expressly for light electrical work, as the tip fits the counter- sink in the porcelain fittings. Ask your dealer for ‘‘Hurwood” No. 55 Screw Drivers. Made in eleven sizes. Manufactured by STANLEY Rute & Lever Co. New Britain. Conn. U.S.A. FOR THE MAN WHO CARRIES y) This Nantioowne, Substantial Harness-Leather TOOL BAG Combines all the good features of the various common leather bags. Strongly built for rough usage. Bottom is three ply and steel studded. Has saw and bit holder, hand strap and shoulder strap with pad. A mighty good all around tool bag. Six sizes ranging from 14x8 inches to 24x8inches. Show thisad to your dealer and insist on the genuine KLEIN tool bag, or write us. Our Illustrated Tool Catalog sent you Postpaid on Request. MATHIAS KLEIN & SONS, Mfrs., Canal Sta. 3, Chicago

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Drop-Forged of Tool Steel Built For Service \Red D e ’ i TRADE MARK. Needle Nose Side Cutting Plier Made by the leading makers of mechanics’ tools. Tested cut- ting edges; spring-tempered handles and nose. Finely finished gun-metal han- dles, polished head; de- signed for jewelers’, opticians’, machinists’, automobilists’ and other users. From dealers or from us for $1.60. Mention style 655-6 inch. Tool Booklet Free SMITH & HEMENWAY CO., Inc. 126 Coit Street, Irvington, N. J. OTTAWA KEROSENE ENGINES Latest design. Durable, Powerful, Reliable, Massive. Built to do hard, heavy work—to give lasting service. Uses Cheapest Fuel. Pulls 25 to 50% more H-P. than rated. Shipped on three months’ trial. Easy terms. Sizes 14% to 22 H-P. 10-Year Guarantee. Book free—postal gets it. OTTAWA MFG. CO. 1951 King St.. Ottawa, Kans. SMALL POWER FOR THE HOME WORKSHOP The ‘‘Little Pet’’ engine will run small lathes, H cream separators, etc. Runs on gasoline or city gas. Combination countershaft and starter, automatic lubrication and cooling, light weight, quiet as a sewing machine, speed adjustable while running, most up-to-date and best motor for home use. Send for catalogue ‘‘B’’. ELGIN GAS MOTOR CO., Elgin, Ill. TOOL CASES for Machinists and Toolmakers Write for our booklet showing the best built and most practical selection of Tool Cases on the market. We ship direct from factory and guarantee to please you or refund all mon ey AGerslrer Sent, 50 Columbia St. Dayton, Ohio p H Figure it out for Big Profits bi C arging yourself. "This 500 : watt a Auto Storage Batteries Giarger will re- charge 1 to 7 batteries at a time. Current costs oaly 12c to 15¢ per battery. Autoist pays 75¢ to'$1.50. Your profit is 60c to $1.35 on every battery le Other HB owners are making $40 to and more clear profit every month. Socan you. $15 Bite tis Money-Maker in Your Garage © Balance in 9 monthly payments of each, which shou! parti Second $16 frst payracet with trial order.” Wo rishe Absolute money-back guarantee. HOBART BROTHERS CO., Bor S6, Troy, Ohio. = Popular Science Monthly Years of Shop Experience has taught this mechanic that it doesn’t pay to take chances on tool equipment. His reputation as a careful, skilled work- man wasn’t built on haphazard work, but on accuracy and reliability at all times. He learned early in his career the value of accuracy and adaptability in his tools. On older shopmate’s advice, his first tool was a B. & S. and today his kit throughout is equipped with Brown & Sharpe Tools _ For three generations this world-known line has helped mechanics everywhere to more reliable, accurate work. Descriptions of over a thousand varieties of tools besides valuable instructive matter makes Catalog 27 a handy book for your kit. Copy Sent Free on Request BROWN & SHARPE MFG. CO., Providence, R. I., U. S. A.

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Popular Science Monthly The Oliver *100 Typewriter A $2,000,000 GUARANTEE That This $49 Typewriter Was $100—The Sales Policy Alone Is Changed, Not the Machine The Oliver Nine—the latest and best model—will be sent direct from the facto : No money: down. No salesmen: Over a year to payae to you upon approval. Five days’ free need influence you. Be your own salesman and save $51. Mail the coupon now. trial. On March Ist, 1917, we announced The Oliver Typewriter Company’s revolutionary plans. of 15,000 salesmen and agents. Prices Cut in Two “ By eliminating these terrific and mounting expenses, we reduced the price of the Oliver Nine from the stand- ard level of $100 to $49. This means that you save $51 per machine. This is not philanthropy on our part. While our plan saves you much, it also saves for us. The entire facilities of this company are devoted exclusively to the production and distribution of Oliver Typewriters. The Identical Model The Oliver Typewriter Company gives this guar- antee: The Oliver Nine we now sell direct is the exact machine—our latest and best model—which until March Ist, 1917, was $100. This Oliver Nine is a twenty-year development. It is the finest, the costliest, : is the most successful model " that we have ever built. More than that, it is the out. If any type- Ship me a new Oliver Nine for five days’ free in- My shipping point is Do not send a machine until I order it. Mail me best typewriter, in fifty ways, writerintheworld is worth $100 it is this Oliver Nine. TO-DAY THE OLIVER TYPEWRITER CO. spection. If I keep it I will pay $49 at the rate of $3 per month. The title to remain in you until This does not place me under any obligation to buy. If I choose to return the Oliver, I will ship it back at your your book ‘‘The High Cost of Typewriters—The Reason and the Remedy,” your de luxe catalogs that anybody ever turned 1106 Oliver Typewriter Bldg., Chicago, Ill. [| fully paid for. expense at the end of five days. and further information. When writing to Advertisers please Se ee 00, On that date we discontinued an expensive sales force We gave up costly offices in 50 cities. Over 600,000 have been sold. This is the same éom mercial machine used by the U. S. Steel Co.porati the National City Bank of New York, Montgom Ward & Co., Morris & Co., Packers, the Pennsyly Railroad, and a host of others. Simplified Selling Our new plan is extremely simple. It makes § possible for the consumer to deal direct with the producer. : You may order from this adem vertisement by using the coupon a: below. We don’t ask a pennyee down on deposit. EB When the typewriter arrives, put it to every test—use it as you If you decide = to keep it, you have more thang year to pay for it. Our terms ane $3.00 per month. = You are under no obligation: to keep it. We will even refund = transportation charges if return it. Or if you wish additional formation, mail coupon for oy proposition in detail. Don’t Pay $100 Why aow pay the extra tax of $51 when you may obtain a brand new Oliver Nine—a world favorites for $49? Cut out the wasteful methods and ordeme direct from this advertisement. = Or send for our remarkable book entitled, “The High Cost of Typewriters—The Reason and them Remedy.” You will not be placed under the slightestig obligation. E -" ; A ~~ mee 000 SOLD Seention Price, $62.65 THE OLIVER TYPEWRITER COMPANI 1106 Oliver Typewriter Bldg., Chicago, Ill. 7 NOTE CAREFULLY:—This coupon will bring y@ either the Oliver Nine for free trial or further infor tion. Check carefully which you wish. 4 This Coupon Is Worth $51 mention Popular Science Monthly

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The Kodak Letter The star in the window tells the story—their soldier is ‘‘over there.”’ The morning letter of.cheer and hope has been written and with 3 it pictures are going, simple Kodak pictures of their own taking that tell the home story,— pictures that will bring a cheery smile to his : face, a leap of joy to his heart, that will keep bright the fire of courage | in his soul as with the home image fresh in. mind he battles for the -

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