Page
Lawn Sprinkler'Made of a Length of Pipe 923
Dropper Bottle for Bromides 926
A Coating Which Gives the Appearance of Stone to
Wood 927
Detecting Leaks in Inner Tubes with Smoke 927
A Small Refrigerator Suitable for the Milk Bottle 927 Combining Different Woods to Make Fancy Indian
Clubs 928
Fine Aluminum Filings a Violent Elzploaive 929
A Screen Door with an Elxit for Flies 929
Uncleanliness the Trouble-Maker for the Vulcanizer 929
How to Patch an Aluminum Crank-Case 930
An Old Bank Barn Converted into a Tractor Shed 930 The Right Knot for Making Slip Noose About a
Bundle 930
A Chicken Brooder That Does Not Require Heat . 932 Distributirig Cards in a Pack and Disclosing Them 933
Making a Bit Point Take Hold in a Knot 933
A Drill of Self-Hardening Steel for Working Marble 934
Finding Leaks Quickly in Air Tanks 934
Making a Bulb Planter from a Foot Pump 934
Sheet Metal Working Simply Elxplained 935
Large Paper Clip Used in Place of a Key Ring. . . . 936 Dividing Line into Odd Spaces with Ordinary Rule 937
Making a VaJve-Grinuer of an Old File 937
Preventing a Tire from Sticking to the Vulcanizer
Mold 937
Rigid Joints for Making Models in Thin Sheet
Metal 937
A Belt Joint for Use in a Damp Place 938
Collecting Gas from Mud in a Stream of Water . . . 938 A Dust Mulch Cultivator to Keep Moisture in Soil 938 A Coin Used to Close Hole of Broken Oil Window 939 Finding the Speed of a Worm-Gear with a Bit .... 939 Making a Small Syringe to Clean Lubricator
Glasses 939
Measuring Through Obstacles by the Triangula-
tion Method 939
Making a Plumb-Bob Level of a Wood Angle 940
Measuring Circumference with Typewriter Spacing 940 Saving Scrao-Gum When Making Tire Repairs . . 940 Twisting a Wire When Pliers Are Not Available. . 940 Covering an Automobile with Torque-Rod Supi>ort
with Leather Boot 946
RADIO COMMUNICATION
Fastening Binding-Posts on the Ends of Heavy
Wire 147
How to Make a Ten-Ampere Key for Wireless ... 147 A Perfected Slider for Tuning Coils in Aerial
Apparatus 147
Making Photo-Electric Cells to Work from a Light 148 Inexpensive Stranded Aerial Wire Made of Small
Copper Wires 1 49
An Easily Made Switch for Grounding Aerial Wires 152
The Efficiency of a Wireless Receiving Station ... 152
A Floor-Push for Operating the Test Buzzer 152
How to Become a Wireless Operator 153
Valdemar Poulsen's Mercury Drop Impulse- Amplifier 1 56
Constructing a Simple Variable Condenser Switch . I 57
An Elasily Learned Emergency Telegraph Code. . . 158 A Quick Method of Removing Enamel from
Magnet- Wire 1 58
What Radio Readers Want to Know 1 59
The Wireless Detective 232
Conveying Music by Wireless — A Modern Miracle 247
A Knob-Control for an Inductively Coupled Tuner 308
How to Make a Portable Aerial for Wireless 308
How to Become a Wireless Operator 309
A Reliable Radiation and Tuning Indicator 314
Measurement Units of Wireless Inductance 315
Hairspring of a Watch as a Detector-Point Support 316
An Airtight Quenched Spark-Gap 316
Spark Sender for Sustained Wireless Waves 317
Strain Insulator Construction for Aerial Lines. . . . 318
Malunga Coil Slider from a Fountain Pen Clip. . . 318
What Radio Readers Want to Know 319
A Concealed Rheostat for Audion CabineU 467
Increasing the Spring Tension on Vibrator Adjust- ments 467
Device for Testing Spark-Plugs Without Removing
Them 468
Heated Wire Is Telephone Transmitter 468
Scale for Inductive Coupler for Making Log-Book 468
New Patent on Interrupter Spark-Gap 471
An Emergency Aerial Using Door-Bell Wires 474
��Page Increasing the Frequency in Radio-Telegraphy. . . 474
How to Become a Wireless Operator 475
An Easily Erected Antenna for Wireless Operators 478
A New Mercury Interrupter for Spark Coila 479
High Frequency Tesla Coil for Ellectrical Experi- menters 480
Testing Wires and Battery Terminal* for Polarity
with Litmus Paper 480
New York Police Use Wireless 531
Succeeding in Radio Work 626
Delicate Recorder for Wireless Telegraph Signals. . 627
A Handy Method for Voltage Testing ; . 628
How to Become a Wireless Operator 629
An Easily Constructed Detector-Stand for Wireless 633 A Mechanical Rectifier as a Wireless Receiver. . . . 634
Making an Enclosed Rotary Spark Gap 635
A Method of Measuring Antenna Capacity .... 638
Making Money by Wireless 710
Signzdiing "by Wireless" Without Instruments. . . 787 Holding the Telephones Tightly Against the Ears 790 A Homemade Floor Push Button for Annunciators 790 Imitating Hard Rubber with Fiber as a Base. . . . 790
Using a Well for Ground Connection 790
Armature Winding for Small Series Motor 791
Calibrating the Receiver for a Wireless Set 792
Making Small Slots in the Frame of Pancake Helices 793 Making a Simple Relay Key for Wireless Operators 794
A Multiple Key for Wireless Messages 794
A Multiple Electrode Rotary Spark-Gap 794
A Novel Crystal Support Made of Flashlight Globe 794
Wireless in the Trenches 795
Improving the Wireless Aeroplane Set 799
Switch Points for Radio Instruments 799
How to Make a Sending Oscillation Transformer. . 800
The Sensitivity of the Telephone Receiver 800
New Wireless Station on African Coast 950
Precise Resistance Measurement by the Volto-
meter- Ammeter Method 951
Increasing the Efficiency of the Poulsen Arc 952
An Elxperimental Wireless Aerial Made of Zither
Strings 953
Making a Tuning Coil Slider writh a Good Contact 953
A Simple Elx{>erimental Spark-Gap in a Case 953
Connections for Vacuum Tubes in Use with Wire- less Telephony 954
Increasing the EAciency of a Receiving Outfit. . . 954
A New Rotary Variable Condenser 955
An Improved Method of Aerial Construction. . . . 960 Some Useful Hints for the Radio Operator 960
RAILWAYS
Going to School in a Freight Car 22
A Fireless Locomotive 45
Putting Railroad Wheels on Automobiles 82
A New Railway Handcar Mowing-Machine 83
Scrubbing Brushes by the Mile for Cleaning Loco- motives 117
Car-Pullers Take the Place of Switch Elngines 195
The Old Soda Fountain on Wheels 263
Delivering Treun Orders to Conductor and Engineer
on Sp>eeding Trains 324
Rescuing a Drowned Locomotive 354
Light Railroading Accomplished by Automobile. . 362
A Land Ride for Whales 384
Meat Packing with the Aid of an EJectric Railway 414 Building a Street Car Line Without.Stopping Work
or Cars 435
Moving a Railway Car by Hand 538
Alaska's "Pupmobile" Railroad 584
Safeguarding Open Drawbridges 599
Railroading in Alaska Is Still Far from Rapid. . . . 664
Clearing the Tracks of a Crippled Car 678
A Portable Electric Welding Apparatus 734
Locomotive Coal Machinery 910
Dispatching Cars on One-Track Linea 918
Shower Baths for Hogs 919
SHIPS AND SHIP BUILDING
The Elnd of One of Farragut's Old Flagahipa 13
The Superdreadnought Pennsylvania 17
Building a Ship Like Caesar's 74
Rich Vagabonds of Florida Rivers 219
The Biggest Battle Cruiser 268
Floating Safes for Ocean Liners 323
A Cargo of Dried Codfish Sunk a Schooner 349
A Round Trip to the North Pole in Ten Day*. . . 434
The Life-Preserver Chair Cushion 486
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