Picric acid, 152, 231. powders, 157, 189.
Picrates, 154, 231.
Polarised light and nitro-cellulose, 218.
Position of the NO_{2} group in nitro-explosives, 2, 3, 16.
Prentice's nitric acid plant, 43.
Pressure gauge, 282.
Primers of gun-cotton, 166.
Properties of dynamite, 116. gelatine compounds, 130.
Pulping gun-cotton, 65.
Pyroxyline for celluloid, 96. solvents for, 101.