Middle Ages, 46, 47, 474

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

Phoenicians, 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