Stevenson, Robert Louis, quoted, 177 Stores, 13 St. Paul, 43 St. Paul's Cathedral, 300 Street-lighting: development of, 152-162 Sugar, 22 Sulphide of iron, 18 Sulphur, 18, 21, 179, 180, 294 Sulphuric acid, 21, 22 Sun, 8, 16, 19, 20 Swan, 129 Syracuse, 19 Syria, 153 Tallow, 34, 35, 51, 52 Tantalum: 132; filament lamps, 133 Tar, 68, 106 Telegraphy, 195 Telephony, 194 Textiles, 256 Thames, 169 Theaters, 9, 319 _et seq._ Thoria, 85 Tin, 262 Tinder-boxes, 18, 19, 22 Travelers Insurance Company, 227 Trees, 26 Troy, 42 Tuberculosis, 273 Tungsten lamp, 161 _et seq._, 187, 261, 290, 303 Typhus, 273 Ultra-violet rays: 126, 150; in photographic electricity, 267, 268; 270, 272, 294 United States: petroleum in, 57; gas-consumption in, 99; 164, 165, 166 United States Geological Survey, cited on sale of gas, 222 United States Military Intelligence, 225, 226 Vacuum tubes, 81, 286 Venetians, 195 Ventilation, 13 Verne, Jules, 143 Vestal Virgins, 42 Volcanoes, 166 Volta, 111, 112, 127 Voltaic pile: construction of, 111, 127 Von Bolton. _See_ Bolton. War: and artificial light, 11, 178-193 Washington, 305 Water: sterilization of, by artificial light, 280 _et seq._ Watson, Dr. Richard, 67, 68 Watt, 94 Waves: electro-magnetic, 68, 86, 125 _et seq._ Wax, 34, 46, 51 Way: mercury-arc produced by, 124 Wells, 61 Wells, H. G., cited, 148 Welsbach, Auer von: 61; invention of mantle by, 99, 100, 133 Wenham, 78 West Indies, 25 Whale-oil, 31 Wicks, 35, 36, 53, 54, 58, 59 Winsor, 72, 73. _See also_ Winzler. Winzler. _See_ Winsor. _Wolfram._ _See_ Tungsten. Wood, 26, 27, 28 Woolworth Building, 302, 303 Wounds: treatment of, by artificial light, 10 X-ray: production of, tubes during War, 131; 137, 150, 270, 280 Young, James: discovers petroleum, 56 Yttria, 85 _Zeitung_, Cologne: 157; extract from, on street-lighting, 158 Zinc, 125, 130, 267 Zirconia, 84, 85 Transcriber's List of Corrections LOCATION ORIGINAL CORRECTED Chapter II and similiar material and similar material Chapter XIII as a constant level at a constant level Chapter XIV the carbons to distintegrate the carbons to disintegrate Chapter XV John Pechham John Peckham coated with an allow coated with an alloy with various billiant with various brilliant key in depressed key is depressed Chapter XVI has nearly doubled have nearly doubled Chapter XVII this own indifference their own indifference Chapter XXIII Nature's lighting varied Nature's lighting varies Chapter XXIV so-called cadelabra so-called candelabra possibilties possibilities