tag="{http://www.w3.org/1999/xhtml}a">168

XI. The Electric Sparking Equipment for a Gasolene Engine 178 XII. Electricity From Central Stations 204 XIII. Electricity From an Old Mill 218 XIV. Doing Chores by Electricity 240 XV. Electric currents from Chemical Action and Chemical Action from Electric Currents 248 XVI. Electrocution at Millville 271 XVII. The Telephone 274 XVIII. Electric Bell Outfit for the Cottage 296 XIX. Using Electricity to Aid the Memory 300 XX. The Electric Brick Oven 305 XXI. Electric Waves 309 XXII. Ringing Bells and Lighting Lamps by Electric Waves 324 XXIII. Telegraphing by Electric Waves 329 XXIV. Halley's Comet and Electric Waves 333 XXV. How the Idea of a Universal Ether Developed 339 XXVI. Electric Currents Cannot Be Confined to Wires 349 XXVII. Wireless Telegraphy In Earnest 355

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ILLUSTRATIONS

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ELECTRICITY AND ITS EVERYDAY USES

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I

THE DYNAMO AND THE POWER STATION

One day Harold expressed a desire to see the dynamos, five miles away, which furnish the electric light in our apartment. So I told him to invite his best friend to accompany us and we would go.

When we were some distance from the station the boys noticed the very tall chimneys and inquired why tall chimneys were needed for dynamos. I explained that the dynamos were run by steam-engines, and steam-engines required the burning of coal. "Oh!" said Ernest, Harold's friend, "I read in the paper that electricity is the rival of steam and is going to drive out the steam-engine." I suggested that we were about to see some steam-engines driving electricity out of that power station. But more seriously, I explained that steam-engines were