Primitive torch and open lamp, p. 202—Tallow candle and perfected lamp, p. 205—Gas lighting, p. 207—The incandescent gas mantle, p. 208—Early gas mantles, p. 209—How the incandescent gas mantle is made, p. 211—The introduction of acetylene gas, p. 212—Chemistry of acetylene gas, p. 214—Practical gas-making, p. 215—The triumph of electricity, p. 218—Davy and the first electric light, p. 220—Helpful discoveries in electricity, p. 222—The Jablochkoff candle, p. 223—Defects of the Jablochkoff candle, p. 225—The improved arc light, p. 226—Edison and the incandescent lamp, p. 228—Difficulties encountered in finding the proper material for a practical filament, p. 230—"Parchmentized thread" filament, p. 233—The tungsten lamp, p. 234—The mercury-vapor light of Peter Cooper Hewitt, p. 236—Advantages and peculiarities of this light, p. 240.
CHAPTER XII
THE MINERAL DEPTHS
Early mining methods, p. 242—Prospecting and locating mines, p. 243—"Booming," p. 246—Conditions to be considered in mining, p. 248—Dangerous gases in mines, p. 249—Artificial lights and lighting, p. 251—Ventilation and drainage, p. 252—Electric machinery in mining, p. 253—Electric drills, p. 254—Traction in mining, p. 256—Various types of electric motors, p. 257—"Telphers," p. 261—Electric mining pumps, p. 263—Some remarkable demonstrations of durability of electric pumps, p. 265—Electricity in coal mining, p. 266—Electric lighting in mines, p. 269.
CHAPTER XIII
THE AGE OF STEEL
Rapid growth of the iron industry in recent years, p. 271—The Lake Superior mines, p. 272—Methods of mining, p. 273—"Open-pit" mining, p. 274—Mining with the steam shovel, p. 276—From mine to furnace, p. 278—Methods of transportation, p. 279—Vessels of special construction, p. 281—The conversion of iron ore into iron and steel, p. 283—Blast furnaces, p. 284—Poisonous gases and their effect upon the workmen, p. 286—From pig iron to steel, p. 287—Modern methods of producing pig iron, p. 288—The Bessemer converter, p. 289—Sir Henry Bessemer, p. 291—The "Bessemer-Mushet" process, p. 293—Open-hearth method, p. 294—Alloy steels, p. 295.
CHAPTER XIV
SOME RECENT TRIUMPHS OF APPLIED SCIENCE
The province of electro-chemistry, p. 298—Linking the laboratory with the workshop, p. 299—Soda manufactories at Niagara Falls, p. 300—Producing aluminum by the electrolytic process, p. 300—Old and new methods compared, p. 301—Nitrogen from the air, p. 303—What this discovery means to the food industries of the world, p. 304—Prof. Birkeland's method, p. 307—Another method of nitrogen fixation, p. 309—Cost of production, p. 312—Electrical energy, p. 313—Production of high temperatures with the electric arc, p. 314—The production of artificial diamonds by the explosion of cordite, p. 315—Industrial problems of to-day and to-morrow, p. 316.