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

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

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