Part 43

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

Railway Signal Association, 205

Railways: light-signaling applied to, 205

Ramie fiber, 101

Rane, 250, 251

Rare-earth oxides: 85; properties of, 88, 99

Recreation, 9

Redruth, 63

Reformation: ceremonial uses of light during the, 48, 49

Rheumatism, 275