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;