XXV Aaron, 43 Accidents: 8 ; street-lighting in relation to, 225 et seq. ; percentage (table) of, due to improper lighting, 231 Acetylene: 62 ; light-yield of, 106 , 107 , 170 , 187 , 191 Actinic rays: effect of, upon human organism, 275 Africa, public lighting in ancient, 31 Agni, god of fire, 40 Air-pump, 130 Air-raids, 225 Alaska, 18 , 29 Alchemy, 20 Aleutians, 18 Alexandria, 43 , 163 Allylene, 106 Aluminum, 108 , 179 , 180 Amiens, Treaty of, 69 Amylene, 106 Aniline dyes, 106 Animal: distinction between, and human being, 3 ; 15 ; production of light, 24 et seq. ; sources of light, 30 , 31 ; oils, 51 Antimony, 294 Antioch, 153 Arago, 114 , 196 Archbishop of Canterbury, 49 Archimedes, 19 Arc: lamps, 69 , 89 ; electric, 111 et seq. ; distinction between spark and, 112 ; Davy's notes on electric, 113 ; formation of, 115 , 116 ; Staite and enclosed, 117 , 118 ; principle of enclosed, 118 , 119 ; types of, 120 ; flame-, 121 , 122 ; luminous, 122 ; electric, 127 ; luminous efficiency of electric (table), 124 ; 160 et seq. ; -lamp in lighthouses, 168 et seq. ; magnetite-, 187 ; 261 Ardois system of signaling, 199 Argand, Ami: 52 ; inaugurates new era in artificial lighting, 53 , 54 ; 63 , 70 , 76 , 77 , 78 , 97 , 167 , 196 Argon, 137 Aristophanes, "The Clouds," 19 Art Museums, 9 , 13 , 322 , 323 Asbestos, 170 Asia: public lighting in ancient, 31 , 39 Automobiles, 238 Babylon, 39 Bacteria: effect of artificial light upon, 272 et seq. ; 281 , 282 Bailey, Prof. L. H., 250 Baltimore, 98 Bamboo: carbon filaments, 169 Bartholdi, 302 , 303 Beacons. See Lighthouses. Beck, 186 Beecher, 72 Beeswax, 35 , 51 Benzene, 106 Bible, cited on importance of artificial light, 42 - 44 "Bluebird, The," Maeterlinck, 9 Blue-prints, 261 Bollman, 98 Bolton, von, 132 , 133 Bombs, illuminating, 182 et seq. Boston Light, 164 , 165 , 166 , 177 Bowditch, production of regenerative lamp by, 78 , 79 Boy Scouts, 17 Bremer, 120 Bristol University, 252 Brush, 68 , 159 Building, 8 Bunsen, 81 , 85 , 89 , 148 , 149 Bureau of Mines: cited on open flames, 234 ; 236 Burning-glasses, 19 , 20 . See also Lenses. Butylene, 106 Byzantium, 34 Cæsar, 163 Canada, 254 Candle-hour, defined, 215 Candles: progress and, 7 ; 25 , 28 , 29 , 30 , 33 ; religious uses of, 34 , 35 ; as a modern light-source, 36 , 37 ; ceremonial uses of, 38 et seq. ; 44 , 48 , 57 , 82 , 97 , 222 , 299 , 304 Calcium, 107 , 108 Carbolic acid, 106 Carbon: 53 , 80 , 81 ; physical characteristics of, 80 , 81 ; 90 , 104 , 105 , 128 , 129 , 144 , 170 Carbon filament: 127 et seq. ; preparation of, 129 , 130 , 131 ; luminous efficiency of, 131 , 132 ; lamps, 161 ; lamps in greenhouses, 250 et seq. Carbons, formation of, 115 , 116 Carbureted hydrogen, 75 Carcel, invention of clockwork lamp by, 54 , 55 Cat-gut, 130 Ceria, 85 , 101 Charleston, S. C., 185 Charcoal: 113 ; uses of, for electrodes, 115 Chartered Gas Light and Coke Co., London, 74 Chemistry: artificial light and, 256 - 268 Chicago, 62 , 304 , 305 Chimneys, 54 , 60 , 62 China, 19 , 31 , 32 Chlorate of potash, 22 Christ, 33 , 46 , 47 Christians, "children of light," 42 Christmas trees, 43 , 304 Chromium, 294 Church of England, 49 Cities: economy of artificial lighting in congested, 13 Civilization: effect of artificial light upon, 4 et seq. ; fire and, 15 Clark, Parker and, 139 Clayton, Dr.: invention of portable gas-light by, 64 ; quoted, 64 , 65 ; experiments of, with coal-gas, 67 Claude, 147 Cleaves, Dr., quoted, 276 , 277 Clegg, Samuel: 74 ; gas-lighting accomplishments of, 75 , 76 Cleveland, 159 "Clouds, The," Aristophanes, 19 Coal: 32 ; as a light-source, 55 ; supply, 223 ; 228 Coal-gas: 63 et seq. ; public lighting by, developed, 70 et seq. ; analytical production of, 103 , 104 ; yield of, retort (table), 105 ; analysis of, 106 Coal-mines, 234 et seq. Cobalt, 294 Coke, 68 , 105 Cologne, 157 , 158 Colomb, Philip, 197 Color: 9 ; relation of artificial light to, 284 et seq. Colza, 31 , 52 , 167 Combustion, 82 et seq. Commerce, 8 , 97 Constantine, 42 Copper, 262 , 295 Cornwall, 63 Cotton: 101 ; carbon filaments, 129 , 130 Cromartie, 78 Crookes, 90 , 146 Crosley, Samuel, improvement of gas-meter by, 76 Crusies, 32 Daguerre, 258 Dancing, 346 Davy, Sir Humphrey: 33 , 68 , 73 ; first use by, of charcoal for sparking points, 112 ; notes of, on electric arc, 113 ; 114 Daylight, artificial, 12 : 284 et seq. ; application of, 287 Daylighting, 12 - 14 Dollond, 195 Doty, 61 , 167 Drake, Col. E. L., discovery of oil in Pennsylvania by, 56 Drummond, Thomas: 171 , 185 , 196 ; quoted on signaling, 197 Dudgeon, Miss, 251 , 252 Dyes, 256 , 265 East Indies, 29 Eddystone Light, 166 , 167 Edison: and problem of electric incandescent filament lamps, 128 et seq. ; 129 ; quoted on birth of incandescent lamp, 130 Edward I, 274 Edward VI, 49 Efficiency, effect of artificial light upon, 14 Eggs: relation of artificial light to production of, 247 , 248 Egypt: 31 ; sacredness of light in ancient, 39 ; 153 , 195 Electric filament: 81 , 127 et seq. : approximate value of, lamps (table), 138 Electric pile: construction of, 111 ; 127 Electricity: 13 , 22 ; as a light-source, 57 ; for home-lighting, 62 , 84 ; 87 , 89 ; ignition of gas by, 102 ; lighting by, 109 et seq. Electromagnetic waves, 68 , 86 , 87 Electromagnets, 114 , 116 Electrodes, 113 , 114 , 115 et seq. ; life of, 122 Elizabeth, Queen, 274 England: 32 ; petroleum discovered in, 56 ; gas-lighting in, 63 et seq. ; 166 , 251 , 274 Erbia, 85 Esquimaux: 18 ; use of artificial light by, 31 Ethylene, 106 Factories: 13 ; artificial light in, 239 et seq. Faraday, 113 Filaments, carbon, 129 et seq. Finsen: 273 , 274 , 275 ; on stimulating action of artificial light, 277 ; 279 , 280 Fire: importance of, to man, 5 et seq. ; man's dependence upon, 15 ; mythical origin of, 16 ; making, 17 et seq. ; production of, in the stone age, 18 ; in early civilization, 19 ; ancient worship of, 29 , 299 Fireflies: 24 , 81 , 96 , 148 , 149 , 150 "First Men in the Moon, The," H. G. Wells, cited, 148 Fish: artificial light as bait for, 249 Flame-arcs, 120 , 121 , 122 , 187 Flames: 86 , 88 , 89 ; open, 233 , 234 et seq. Flint, 33 Fool's gold, 18 Fort Wagner, 185 France: lamps in, 55 ; early gas-light in, 72 Franchot, invention of moderator lamps by, 55 Frankland, 77 Franklin, Benjamin: 165 ; quoted, 210 - 212 ; 213 Fresnel, 167 , 196 Friction, 16 , 17 Gas: 13 , 22 ; discovery of coal, 32 , 33 ; early uses of, as light-source, 63 et seq. ; installment of, pipes in England, 63 , 64 ; Shirley's report on Natural, 66 , 67 ; first public display of, lighting, 69 ; cost of, lighting, 71 ; first attempt at industrial, lighting, 72 ; first English, company, 74 ; first, explosion, 75 ; house, lighting, 76 , 77 ; 80 , 82 ; spectrum of, 90 ; modern, lighting industry, 97 et seq. ; origin of lighting by, 98 ; first, works in America, 98 ; growth of, consumption in United States, 99 ; electrical ignition applied to, lighting, 102 ; pressure, 102 , 103 ; water, 105 ; carbons in, 106 ; production of Pintsch, 109 , 110 ; salts applied to, flames, 120 ; 157 ; Census Bureau figures on cost of, plants, 221 , 222 ; 224 , 341 Gas-burners: 63 , 64 , 77 ; candle-power of pioneer (table), 79 ; improvements in, 84 Gas-mantle: 61 , 81 ; influence of, 99 ; characteristics of, 100 et seq. ; 187 Gas-meter, Clegg's, 76 Gasolene: lamps, 55 ; 57 Gassiot, 114 Gauss, 196 Geissler, 146 General Electric Company, 132 , 135 , 136 Germany: development of lamps in, 56 ; early gas-lighting in, 72 Glass, 195 , 290 et seq. Glowers, 139 Glow-worms, 24 Glycerides, 52 Gold, 293 Gout, 275 Gramme dynamo, 117 Grass: 18 ; carbon filaments, 129 Greece: 39 ; sacred lamps in ancient, 41 ; 42 Greenhouses, carbon-filament lamps in, 250 et seq. Hall of Fame, 134 Happiness, effect of artificial light upon, 14 Hayden and Steinmetz, 253 Health, artificial light in relation to, 269 - 283 Helium, 89 Hemig, 155 Hemp, 21 Henry, William, 75 Herodotus, 56 Hertz, 68 Hertzian waves, 271 Hewitt, Cooper, produces mercury-arcs, 124 , 125 Home: artificial light in relation to, 6 ; lighting, 325 et seq. Hindu: light in, ceremonials, 40 Hudson-Fulton Celebration, 306 Huygens, 195 Hydrocarbons, 82 Hydrogen, 81 Illiteracy, artificial light and, 9 Invention, 7 , 97 Iowa, 238 Iridium, 129 Iron, 18 , 262 , 294 Iron pyrites, 18 Italy, 249 Jablochkov: electric candle of, 117 Jamaica, 19 Jandus, 118 , 122 Japan: 19 ; use of oil in, 30 ; 281 Jerusalem, 43 Jews: artificial light among, 40 Journal , Paris, quoted, 210 - 212 Kerosene: 57 ; weight of, lumens, 60 ; 62 , 187 , 233 Kitson, platinum-gauze mantle applied by, 61 Laboratories: achievements of, 137 Lamps: 16 , 25 ; Roman, 30 ; 31 ; invention of safety, 33 ; ancient funereal, 39 ; sacred, of antiquity, 41 ; ceremonial, 44 ; scientific development of oil, 51 et seq. ; Holliday, 55 ; Carcel, 54 , 55 ; Franchot's moderator, 55 ; gasolene, 55 ; development of, in Germany, 56 ; air pressure, 61 ; supremacy of oil, ends, 62 ; Bowditch's, 77 , 78 ; 80 , 97 ; mercury-arc, 126 ; electric incandescent filament, 127 et seq. ; gem, 132 ; tungsten, 133 et seq. ; luminous efficiency (table) of incandescent filament, 141 ; 299 ; in home, 328 - 333 Lange, 167 Lard-oil, 51 Lavoisier, 195 Lead, 262 , 294 Le Bon, 72 "Legend of Montrose, The," Scott, cited on primitive lighting, 27 Leigh, Edmund, quoted, 226 Lenses, 20 , 171 et seq. Libanius, quoted, 153 , 154 Liberty, Statue of, 301 , 302 , 303 Libraries, 9 Light: relation of artificial, to progress, 3 et seq. ; as a civilizing agency, 3 - 14 ; primitive man and artificial, 4 ; Milton, quoted on importance of, 5 ; artificial, and science, 7 ; artificial, and industrial development, 8 ; Maeterlinck's tribute to, 9 ; Lincoln's debt to artificial, 9 ; symbolism of, 9 , 10 ; therapy, 10 ; in war, 11 ; adaptations of, 12 ; 13 ; mythical origin of artificial, 16 ; earliest source of, 16 ; production of, in stone age, 18 ; matches as source of, 21 ; animals as, sources, 24 , 25 ; primitive sources of, 24 - 37 ; evolution of artificial, sources, 24 - 37 ; development, 28 et seq. ; early outdoor use of artificial, 28 ; Roman uses of artificial, 30 ; beginning of scientific, 33 , 34 ; candles as modern, source, 36 , 37 ; symbolism and religious uses of, 38 et seq. ; Bible cited on artificial, 42 - 44 ; in relation to worship, 43 , 45 , 46 ; Argand's contribution to, 53 , 54 ; coal as, source, 55 ; early uses of gas as, source, 63 et seq. ; as a public utility, 70 ; first installation of industrial gas, 72 ; science of, production, 80 et seq. ; causes of, radiation, 80 , 81 ; 83 ; lime, 84 ; electric, 89 et seq. ; principle of, production, 90 , 91 ; sources, 93 ; various gas-burners', supply, 95 ; relative efficiency of, sources, 95 , 96 ; in the home, 97 ; influence of, upon science, invention, and commerce, 97 et seq. ; yield of acetylene, 106 , 107 ; electric, 109 ; influence of gas upon development of artificial, 110 ; development of artificial, 111 et seq. ; efforts to improve color of mercury-arc, 125 ; electric-incandescent-filament, 127 et seq. ; effect of tungsten, upon, 133 et seq. ; of the future, 143 - 152 ; in warfare, 178 - 193 ; signaling, 194 - 207 ; cost of, 208 - 224 ; and safety, 225 et seq. ; improper use of, 229 , 230 ; comparison of daylight and artificial, 240 ; reducing action of, 258 ; bactericidal action of, 272 et seq. ; modifying, 284 et seq. ; spectacular uses of, 298 - 309 ; expressiveness of, 310 - 324 ; utility of modern, 325 - 340 ; evolution of the art of applying, 341 - 356 ; mobile, 347 , 348 , 349 , 350 ; psychological effect of, 351 et seq. ; as an accompaniment to music, 352 - 354 Light-buoys, 10 , 169 Lighthouses: 10 , 163 - 177 ; optical apparatus of, 172 et seq. Light-ships, 10 , 169 Lighting-systems: comparison of, 12 - 14 Lime, 84 , 107 , 108 , 294 Lincoln, Abraham, 9 Linen, 18 Link-buoys, 28 Lithopone, 265 , 266 Liverpool, 167 Living: comparison of, standards, 238 et seq. London, 152 , 154 , 155 , 156 , 157 , 202 London Gas Light and Coke Company, 74 Lucigen, 61 Lumen-hour: defined, 215 Lumens: 60 , 94 , 215 Lutheran Church, 49 Lyceum Theatre, London, 73 Maeterlinck, Maurice, 9 Magazines, 8 Magdsick, H. H., 303 Magnesia: 84 ; Nernst's application of, 138 Magnesium, 179 , 180 Magnetite arc, 187 Man: distinction between, and animal, 3 ; artificial light and early, 4 ; light-sources of primitive, 25 Manganese, 262 , 268 , 294 Mangin, 188 Mann, 129 Mantles, 95 Manufacturing, 8 Marconi, 68 Marks, 118 Matches: as light-sources, 21 ; 22 , 82 Maxwell, 68 Mazda lamps, 289 , 339 Mecca, 40 Mediterranean Sea, 163 Mercury-arc: Way's, 124 ; 125 , 126 ; quartz, 125 , 126 ; attempts to improve color of, light, 125 Middle Ages, 46 , 47 , 274 Milton, quoted, 5 Mirror, 19 Mohammedans, 40 Moore, Dr. McFarlan, 146 , 147 Morality, effect of light upon, 9 Morse code: application of, to light-signaling, 198 , 199 Moses, 195 Moving-pictures, 9 , 260 , 261 Munich, 72 Murdock, William: installment of gas-pipes by, 63 ; 68 , 69 , 70 ; quoted on industrial use of artificial, 71 ; 72 , 73 , 74 , 76 , 78 , 217 , 309 Museums: 13 ; utilization of artificial light by, 322 , 323 Music: light as an accompaniment to, 352 - 354 Mythology, 16 Nantes, 85 Napoleon, 111 Napthalene, 106 National Heat and Light Co., 72 , 74 Natural gas, 99 Navesink Light, 206 Nernst, 138 , 139 Newspapers, 8 Newton, Sir Isaac: 7 ; quoted on discovery of visible spectrum, 87 ; 88 New York, 98 , 165 , 166 , 206 , 302 , 304 Niagara Falls, 108 , 306 Nickel, 262 Nielson, 77 Niepce, 258 Niter, 21 Nitrogen, 137 Norfolk, 169 Obesity, 275 Offices, 13 Oil: as a light-source, 29 et seq. ; development of, lamps, 51 et seq. ; 155 ; in lighthouse, 165 et seq. ; 222 , 224 , 299 O'Leary, Mrs., and her lamp, 62 Olive-oil, 51 , 52 , 167 Orkney Islands, 29 , 177 Osmium, 133 Oxygen: relative consumption of, by oil-lamps, 58 , 59 ; 262 Ozone, 262 Painting, 342 , 343 , 347 , 348 , 349 Pall Mall, 74 Panama-Pacific Exposition: 304 ; artificial lighting of, 306 , 307 , 308 , 309 Paper: 18 ; carbon filaments, 129 , 130 Paraffin, 35 , 57 Parker and Clark, 139 Paris: experimental gas-lighting in, 83 , 84 ; Volta in, 111 ; 154 , 185 , 210 , 212 , 213 Peckham, John, 195 Pennsylvania: discovery of oil in, 56 Periodic Law, 145 Petroleum: 35 , 51 , 55 ; discovery of, 56 ; constitution of crude, 57 ; 58 , 214 Pharos, 163 Philadelphia, 98 , 99 , 157 Phillips and Lee, 70 , 72 "Philosophical Transactions of the Royal Society of London," 33 ; quoted on industrial lighting, 63 ; Shirley's report on natural gas in, 66 , 67 ; quoted, 87 Phœnicians, 34 , 39 Phosphorus, 21 Photo-micrography , 12 Photography: 126 ; early experiments in, 258 ; development of, 259 ; 291 , 292 Picric acid, 106 Pigments, 265 Pintsch: production of, gas, 109 , 110 , 170 Pitch, 106 Plant-growth: artificial light and, 11 , 249 et seq. Platinum, 85 , 128 , 129 , 262 Plumbago, 113 , 130 Plymouth, 166 Poetry, 346 Police, 162 Potash, chlorate of, 22 Priestley, Professor, quoted, 252 Printing, 8 Progress: influence of fire upon, 15 et seq. Prometheus, 16 , 41 Propylene, 106 Ptolemy II, 163 Quartz: 18 , 19 ; mercury-arcs, 125 ; uses of, 126 ; in skin diseases, 278 , 279 Radiators, energy, 88 et seq. Radium, 150 Railway Signal Association, 205 Railways: light-signaling applied to, 205 Ramie fiber, 101 Rane, 250 , 251 Rare-earth oxides: 85 ; properties of, 88 , 99 Recreation, 9 Redruth, 63 Reformation: ceremonial uses of light during the, 48 , 49 Rheumatism, 275 Robins, Benjamin, 201 Rome, 30 , 32 , 34 , 39 , 41 , 42 , 44 Röntgen, 270 , 280 . See also X-ray. Royal Society of London: 33 , 63 , 66 , 67 , 70 , 73 ; and first gas explosion, 75 , 111 , 112 Rumford, 167 Rushlights, 28 , 33 Russia, 281 Ryan, W. D'A., 306 Safety: artificial light in relation to, 14 , 225 et seq. Salts: chemical, 88 , 89 ; metallic, 120 ; silver, 257 , 258 Sandy Hook Light, 165 , 166 San Francisco, 304 , 306 - 309 Savages, 3 , 15 , 17 Sawyer, 129 Scheele, K. W., 133 ; quoted, 257 , 258 Schools, 9 Science: light and, 6 , 7 ; 97 ; systematized, 268 Scotland: 26 , 31 , 32 , 48 ; oil industry in, 56 Scott, Sir Walter, cited, 27 , 98 Sculpture: artificial light in relation to, 184 Search-lights, 11 , 169 Section of Plant Protection, 225 , 226 Selenium, 267 , 293 Semaphore, 199 Shells: illuminating, 179 et seq. Shirley, Thomas: quoted on natural gas, 66 , 67 Siemens , 78 Signaling, 194 - 207 Silicon: filament, 140 Silk: artificial, 101 ; carbon-filaments, 129 Simpson, R. E., 227 , 231 Silver, 258 , 293 Skin diseases: treatment of, 278 , 279 , 280 Skylights, 13 Sleep, 8 Smallpox, 274 , 275 Smeaton, 166 Soho, 69 , 72 South Africa, 129 Sparks: 33 , 125 Spectrum: visible, 86 ; Newton quoted on, 87 ; of elements, 89 ; of gases, 90 ; 120 , 121 ; mercury, 124 - 126 Sperm, 31 , 51 , 52 , 167 Spermaceti, 35 , 51 Splinter-holders, 27 , 28 Stage: and artificial light, 319 et seq. ; 343 Staite, 117 , 118 Stearine, 35 , 52 Stearn, 129 Steel, 18 , 33 Steinmetz, Hayden and, 253 Sterilization: quartz-mercury-arc and, 280 , 281 , 282 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