IXDKX TO VOIJME 80 



Page 



Cardboard Tubes 275 



How a Compact Molded Condenser Is Built 275 



Primary Regulator for the Induction Coil 275 



Small Radio Stations 275 



Lowering t^e Decrement 277 



Lighting Audion Bulbs Cheaply 276 



Music by Wireless 278 



A Substitute for An Aerial 280 



Telephone Headbands 280 



A Built-Up Wireless Mast 281 



A Sending Condenser 282 



Adjusting Handles 283 



A New Detector Material 284 



A Good Loose-Coupler Switch 285 



Modified Audion Is New Telephone 285 



Reducing Arcing at Key Contacts 285 



A Quencned Gap with Metal Spacers 286 



Switch Points for Radio Instruments 286 



What Radio Readers Want to Know 287 



A Microphonic Amplifier 437- 



Constructing an Amateur's Aerial 439 



Guying the Mast 442 



A New Tuner Arrangement 445 



Lepel Improves His System 445 



A New Variable Condenser . . .• 448 



The Quenched Gap 448 



A Kick-Back Preventer 448 



How to Become a Wireless Operator 449 



Curious Form of Dustproof Detector Cup 452 



A Rotary Adjustment for Coupling 452 



What Radio Readers Want to Know 453 



Insulating the Ground Connection in Radio Work 613 

 An Easily Made Self-Locking Device for Barn- 



Doors 614 



Converting a Plain Zinc-Gap into an Air Blast 



Spark-Gap 62 I 



Strengthening the Static Field of an Amplifier. . . , 622 

 Overcoming Troubles in a 200-Mcter Wave Outfit 623 



How to Become a Wireless Operator 627 



Employing Kites to Support an Aerial 630 



A New Spark-Gap for Wireless Telephony 63 I 



Making a Crystal Detector from Cheap Materials 633 

 Wireless Telegraph Stations in the West Indies . . 633 

 I ns'ilating and Decorative Enamel for Electro- 

 Magnets 634 



Best Wavelengths for Certain Distances 635 



What Radio Readers Want to Know 636-637 



Converting a Freight Car into a Wireless Station. 639 



The Construction of a One-Mile Receiver 789 



How to Become a Wireless Operator 789 



Making an Inductance Switch for Radio Work. . . 796 



What Radio Readers Want to Know 797 



Simple Method of Remagnetizing Magnets 799 



The Telephone Receiver for Wireless Apparatus. . 799 

 Experiments with Antennas of Varying Lengths. . 800 

 Making the Aeroplane Generate Its Own Power 



for Wireless 842 



Using a Tree as a Mast for a Wireless Station .... 871 



Making an Emergency Aerial for Wireless 948 



How to Become a Wireless Operator 949 



Transformer Trouble in Radio Transmitting 



Apparatus 954 



Practicing the Code Without Using a Buzzer 955 



How to Take Up the Slack on Your Aerial Wires. 955 

 Canada to Protect Her Parks with Radio Service. 955 

 Preventing Interference of Signals by Amplifying. 956 

 A New Direct-Current Transmitter in Radio 



Communication 957 



What Radio Readers Want to Know 958 



RAILWAYS 



End-Door Automobile Express Cars 7 



Driving Railway Spikes with a Motor-Car 26 



Hairpin Curves on a Mountain Trolley Line 48 



Beautifying- Manhattan's Riverfront 86 



Minute Men of the Rails 169 



Boy's Road Wagon Is u Real Locomotive 183 



An Auto Mountain Railway 207 



A Western Railroad's Clay Locomotives 242 



A Railroad Which Fights Its Own Fires 251 



The Senators' Subway 328 



A Locomotive that Burns Pulverized Coal 376 



Feeling the Way 379 



Railroad Treads for Motor-Trucks 391 



Stopping Trains Automatically 433 



Odd Uses for Railroad Cars 500-501 



Solving New York's Freight Problem 546 



Page 



Ten Millions to Save Four Miles 553 



A Danger Signal Which Compels Attention 572 



Our First Armored Car 588 



The Hose Is Mightier Than the Brush 688 



A Motor-Wheel for the Railroad Velocipede 742 



A Locomotive Side-Frame Which Weighs Nearly. 



Seven Tons 829 



A Wind- Deflecting Lookout Mask for Engineers. . 832 



Daylight Lamp Signals 847 



A Device for Adjusting the Ends of Steel Rails. . . 915 

 Transforming a Railroad Water-Tank Into a 



Home for Two 919 



SHIPS AND SHIP BUILDING 



Protecting a Battleship with a Belt of Air 18 



How a Steamer's Engine Room Is Ventilated .... 104 



Charting the Dangers of the Deep 204 



Coaling a Liner with An Elevator 206 



The World's Largest Ships' Register 226 



Pulverized Coal Burners on Our Modern Ocean 



Steamships 230 



A Damaged Lock Gate Repaired by I ts Own 



Water 234 



A Venetian Barge in Boston 258 



A Guard for Mooring Ropes to Prevent Rats from 



Landing 363 



Tethering the Largest of the Super-Dreadnoughts 381 

 Milazzo — the Largest Coal Ship in the World. . . 392 



Cooling a Ship's Laundry 477 



Pocket-Flashlight Distress-Signals 520 



Piping Oil to Ships at Sea 521 



A Fog-Stick for Traffic on the Great Lakes 522 



A Fleet of Indoor Battleships 578 



Detecting Enemy Submarines from a Ship's Look- 



Out 579 



Preventing Ships from Rolling with Fly Wheels . . 592 



The Thousand-Foot Battleship 670 



A Novel Device for Generating Fresh Air in Sub- 

 marines 681 



Telegraphing Through the Ocean 711 



Defending America with Motor Torpedo Boats. . . 721 



Miniature Magnet-Propelled Ships 737 



Discovering Contraband of War 752 



An Endless-Chain Barge Loader 845 



She Lies on Her Side— But They'll Raise Her 880 



SPORTS AND PASTIMES 



Doing Without the Caddy 12 



Golfing at Home 13 



Playing Baseball by Machine 57 



The Five-Wheeled Velocipede 64 



What Ho! The Jitney Yacht 83 



A "Jackomobile" for Two 100 



What Inventors Are Doing for the Fisherman . . . 105 



Camp Fire Maxims ....T 115 



Kite Making at Home — II 127 



How to Make a Practical Gas-Range Lighter .... 156 



Weightmobile Approaches Perpetual Motion 158 



Leaping Horses That Are Unafraid 168 



Another Baseball Game in Disguise I 74 



An Air-Tight Compartment for Canoe Campers. . 184 



Turning Your Racket Press Into a Camp Stool . . . 224 



The Latest in Golf Clubs 246 



"Canal Boats" Which Are Real Water-Shoes... 257 



The First Bird House Ejthibit 260 



Making a Bomb Thrower for Sham Battles 295 



The Wliistling Bicycle Wheel 297 



How to Make a Toy Zeppelin 313 



Ferreting out the Secrets of the Golf Ball 324 



A Metal Disk Supplants the Golfer's Tee 324 



Golfing by the Clock — a New Idea for Golf Courses 325 



What Golfing Sometimes Does to the Feet 325 



Making Your Head Behave While You Hit the Ball 325 



A Paddleless Canoe Propelled by Feet and Hands 326 



Mechanical Joys of Coney Island 394 



Playing Checkers on the Lawn 398 



Good-By to the Pin-Boys in the Bowling- Alley . . . 409 



Battle Ball— a New Sport 420 



Getting Ready for the Clay Birds 421 



A Fascinating Old Sport in a New Dress 436 



The Trench Marble Game and How It Is Played. . 455 



Decoy Ducks That Quack and Swim 509 



The Old Fondness for Cycling Is Coming Back. . . 514 



Hunting the Mud Pigeon 530 



Bucking a Wooden Football Line 554 



Playing Ball with a Revolving Fan as a Target . . 568 



Motoring on Rollcr-Skates 569 



