INDEX TO VOLUME 91 



Page 



Hand Bob-Sleds Made of Barrel Staves 934 



Making Butt Mortises with an Ordinary Rabbet 



Plane 934 



Making a Talking Machine Stylus from a Tooth- 

 pick 934 



Making a Whistling Weather Vane for the Barn . . 934 



Windng a Coil Spring Evenly 934 



Cutting Rafters for Gothic Roof Barn Construction 935 

 Fruit Jar Rubber Ring to Repair Bicycle Tire 



Puncture 935 



The Proper Care of a Soldier's Wardrobe 935 



Improving the Qualities of Cheap Lead Pencils... 936 



A Barrel Stave Iceboat 937 



A Homemade Sight Feed Oil Indicator for an Auto- 

 mobile 938 



A Simple Method of Fastening Umbrella Handles 938 



Simple Designs for Sheet Metal Working. . 939 



Garden Hose Used as a Form for Cement Pipe. . . 941 



Eliminating Noise from Shift Levers 941 



Repairing a Scratch on an Automobile 941 



How to Straighten a Warped Drawing Board. . . . 942 

 Making a High Gloss Finish on a Matt Surface 



Picture 942 



Protecting Drawings on Drawing Board 942 



Setting a Lathe Quickly for Taper Turning 942 



Teeth of a Hack-Saw Blade Used for Spacing on 



Section Liner , 946 



How to Make a Secure Joint in Copper Tubing. . . 948 

 Things to Know About Lubricants for Machinery . 948 

 Constructing a Thermostat to Regulate Furnace 953 

 A Coating to Make a Battery-Box Acid Proof .... 954 

 Heating Sheet Hard Rubber to Cut Round Disks . . 959 

 Lighting the Dash-Board of an Auto from the Side 



Light 960 



Sheet Asbestos to Make a Packing for Steam Chests 960 



RADIO COMMUNICATION 



"Silent Music" — Recreation for the Bedridden. . . 28 

 Curious Circuit for Audion on a Wireless Set. ... 151 



Conversion of Kilometers to Nautical Miles 151 



An Experimental Wireless Aerial Made of Zither 



Strings 151 



To Prevent the Ears Perspiring When Wearing 



Telephones 152 



Mounting Tinfoil on Glass Condenser Plates 152 



How Germany's Secret Service Wireless Stations 



Are Being Weeded Out 1 53 



A Crystal Detector Holder for Wireless Apparatus 155 

 Effect of the Moon and Season on Wireless in the 



Tropics 1 55 



A Trussed Aerial Spreader for Long Wires 1 56 



Position of Wireless Waves Passing Over Land. . . 156 

 Cloudy Days Best for Wireless Wave Signals .... 1 56 

 Improving the Tone of a Test Buzzer Used on Wire- 

 less Detector 1 56 



Simple Construction of a Rotary Gap Disk 1 56 



Simple Solutions of Wireless Problems 157 



Magnetic Brake for a Wireless Rotary Gap 160 



Adjusting the Detector of a Receiving Set 160 



How theJGovernment Seals Unofficial Stations . . 208 

 A Simple Arc Lamp Using a Thermostat Control . . 308 



Slow Acting or Sluggish Relays 308 



An Ingenious Wiring System for Two Inductive 



Transformers 310 



A Variable Condenser for a Receiving Set 310 



An Amplifying Electrostatic Radio Receiver 311 



Treating Cardboard Tubes for Tuners 311 



Strong Wireless Signals in Winter Time 312 



A Testing Set That Does Not Use a Battery .... 312 

 How the Radio Inspectors Trapped a Disorderly 



Amateur 313 



How to Make a Kick-Back Preventer for Wireless 



Apparatus 314 



A Use for Discarded Cylindrical Food Boxes 314 



Variable Primary Coil Using a Switch Instead of a 



Slider 314 



America's New Semi- Wireless System for Telephon- 

 ing from Captive Balloons 315 



A Polarity-Changer for Reversing Lighting Battery 



Current 315 



Dormitory Beds Furnish the Essential for Antennas 3 1 6 



An Insulation for Secondary Terminals 316 



Wireless Work in Wartime 317 



A Simple Fixed Adjustment Detector 320 , 



An Audion Battery Made of Medicine Vials 441 



An Easily Adjusted Detector-Stand 441 



Page 



Wireless Signals Transmitted by Telephone 442 



Fighting the Big Guns with Wireless 443 



Supplanting the School Bell with Wireless 445 



How to Make a Variable Condenser for Five Cents 446 



Wireless Work in Wartime 447 



An Inexpensive and Quickly Made Detector 450 



Relieving the Strains on Aerials 450 



Sustained Wave Telegraphy Between the United 



States and Germany 451 



Double Set of Receivers for Visitors 453 



A High Voltage Lead-in Insulator Tube 453 



Loading Coil in Series with the Secondary 453 



A Ticker Interrupter Made from a Buzzer 454 



A Simple and Attractive Loading Coil 601 



Transmitting Wireless Messages Underground 



Without Aerial 602 



Sending Wireless Messages Under Fire 603 



Construction of a Rotating Arm for a Rotary Gap 606 



Wireless Work in Wartime 607 



A Grid Placed in the Wings of an Airplane 614 



I ncreasing the Efficiency of the One-I nch Spark Coil 787 



Wireless Work in Wartime 793 



A Strong Guy- Wire Anchor for Aerial Poles 797 



A Magnetic Telegraph Key for the Wireless Operator 798 

 Ballast Weights for Antenna to Prevent Aerial from 



Overturning 800 



The Marconi Company Sues the Government .... 913 



Detecting Defective Insulators 914 



The Human Morse Code 950 



An Inexpensive Multi-Point Loading Coil 953 



Water Glass Gage for a Lead-in Insulator 954 



Wireless Work in Wartime 955 



An Easily Constructed High Tension Insulator. . . 959 



RAILWAYS 



This Railroad Crossing Cleans Itself and Eliminates 



Jolts 5 



Attacking Mail-Car Robbers with Deadly Fumes. 27 

 Owens Valley, California, Has a Freight-Car Hotel 87 



Can the Railway Train Be Made Noiseless? 92 



Flushing Streets with Water Pipes on Trolley Cars 107 



Street Railway Smoking Car 214 



The Largest Traveling Kitchen 224 



The Biggest Locomotive 251 



A Refrigerator Car That Really Works 394 



The Most Powerful Locomotive in the World .... 396 



Street Cars Pull Each Other Up , . 41 I 



A Sanitary Dining Car 418 



Solving the Car Shortage Problem 422 



Lest the Engineer Forget 436 



Canning the Baby in a Super Sleeper 513 



How Print Butter Is Shipped to the Retailer 519 



Flagman's Shelter House Built Like a Mosque. . . 551 

 Safeguarding Our Bridge and Railroad Crossings . . 565 

 Putting Driving Wheels Under the Locomotive 



Tender 570 



A Lift Deck for Automobile Freight Cars 592 



A Lumberman's Camp Which Can Be Moved from 



Place to Place on Rails 598 



Special Cars for Persons Carrying Parcels 708 



Loading Cattle on Trains in a New Way 723 



Diminutive Electric Locomotives 738 



How a Railroad Steam-Shovel Traveled Through 



New York City 747 



An Iron "Flag" for Protecting the Railroad Car 



Inspector Against Injury. 755 



Keeping the Trains from Being Blown Off the 



Tracks 824 



A One-Man Rail Grinder 825 



A Labor-Saving Dump Car 884 



SHIPS AND SHIP BUILDING 



Why You Can't Compare Ships in Tons 29 



A New Life-Boat 60 



Salvaging in Armor 93 



Motor Attachment Which Prevents the Rowboat 



Propeller from Being Injured 96 



The Latest Salvaging Device — An Electromagnet . 113 

 An Electric Eye Watches the Smoke Screen During 



a Battle 115 



Practical Motor-Boating 116 



A Two-Million-Dollar Hospital Ship 206 



A Ship with Six Hulls 209 



The U.S.S. "Recruit" 212 



New Type of Life Boat 223 



