Part 39

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