CHAPTER IX.

MANUFACTURE OF GELATINE, AND PRODUCTS PREPARED FROM IT.

Properties of gelatine; Change in the chemical constitution of gelatine produced by concentrated sulphuric or nitric acid; Tannin as a test for the presence of gelatine; Use of gelatine for culinary and medicinal purposes 165

Skin gelatine; Method of manufacture introduced and patented, in 1839, by George Nelson; Process patented, in 1844, by Messrs. J. & G. Cox of Edinburgh 166

G. P. Swinborn’s improved patented process for the preparation of gelatine from hides, skins and glue pieces; Modern process of preparing skin gelatine; “Steeping” the skins 167

Washing and bleaching the skins 168

Digesting the skins; Clarifying the liquors 169

Evaporation of the liquors in vacuo; Drying the cut cakes; Bone gelatine; Materials for this purpose; Crushing the bones; Solution of the glue cartilage 170

Apparatus and improved manner of manufacture employed in the factory of D. J. Briers, described and illustrated 171

Modern process of preparing bone gelatine 179

Colored gelatine; Uses of colored gelatine; Harmless coloring matters; Colors for coloring leaves of gelatine with aniline colors for technical purposes 181

Gelatine for fining purposes; _Gelatine Lainée_; Fining powder for wine and beer; Liquid fining gelatine; Preparation of gelatine from ordinary glue 182

Preparation of gelatine for photographic printing and for photographic purposes in general; Removal of the salts from the gelatine 183

Gelatine capsules for medicinal purposes; Court plaster 184

Gelatine foils; Mode of coloring the foils 185

Gelatine veneers; Principal operations in the manufacture of gelatine veneers 186

Preparation of the plates; Preparation of the glue solutions; Proportions by weight of the mixtures for ten different varieties of imitations of marble and enamel 187

Imitation of mother-of-pearl veneers 188

Pouring the colored solutions of glue upon the plates 189

Preparation of imitations of malachite 190

Transferring the layer of glue to a layer of gelatine 191

Drying and detaching the veneers 192

Water-proofing gelatine veneers; Uses of gelatine veneers; Formo-gelatine and its uses 193

Use of gelatine in bacteriology 194

Artificial silk from gelatine 195