Chapter IX The Physical Chemistry of the Hide-Fibre
Causes of swelling and contraction — The essentials of the tanning process — The constitution of matter — The nature of molecules — Vapour-pressure — Surface-tension — Solution-pressures — Jellies — Crystals — Osmotic pressure — Electrolytic dissociation — Electrolysis — Reactions of ions — Absorption of water by gelatine — Dehydration by alcohol — Action of acids, alkalies and salts on gelatinous fibre — Physical explanation of swelling — Action of acids on gelatine — Action of alkalies on gelatine — Effect of salt — The pickling process PAGE 73