62, 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._;