CHAPTER III.

Natural Sources of Indigo, 124. Syntheses of the Colouring-matter, 126. Carbolic Oil, its treatment and its constituents, 129. Phenol Dyes, 132. Salicylic Acid and its uses, 134. Picric Acid, 136. Naphthalene and its applications, 139. The Albo-carbon Light, 140. Phthalic Acid and the Phthaleins, 145. Magdala Red, 149. Azo-dyes from the Naphthols, Naphthylamines, and their Sulpho-acids, 150. Naphthol Green, the Oxazines, and the Indophenols, 161. Creosote Oil, 163. The Lucigen Burner, 163. Anthracene Oil, 167. The Discovery of Artificial Alizarin, and its effects on Madder growing, 167. The industrial isolation of Anthracene and its conversion into Colouring-matters, 171. Pitch, and its uses, 176. Patent Fuel, or Briquettes, 178. Coal-tar products in Pharmacy, 178. Aromatic Perfumes, 185. Coal-tar Saccharin, 186. Coal-tar Products in Photography, 188. Coal-tar Products in Biology, 192. Value of the Coal-tar Industry, 194. The Coal-tar Industry in relation to pure Science, 196. Permanence of the Artificial Colouring-matters, 198. Chronological Summary, 200. Addendum, 202.

COAL; AND WHAT WE GET FROM IT.