Cotton or other vegetable fibres moistened with oil, readily undergo oxidation, with so much evolution of heat as sometimes to cause spontaneous combustion; but the oxidation products are easily and completely removed by alkaline solutions, leaving the fibre in its original state, as indeed is noted by Lietzman (_loc. cit._). The finishing processes consist in staking during drying to retain softness, and in whitening and smoothing the flesh (or sometimes both sides) on the fluffing wheel. Skins for gloves, &c., are bleached like linen, by sprinkling and exposure to the sun; or more rapidly by treatment with a weak solution of potash permanganate, and subsequently with sulphurous, or very dilute sulphuric acid, to remove the brown manganous oxide formed (Barreswil, Dingl. Polyt. Jour., 161, 312). Gaseous sulphurous acid from burning sulphur may also be used for bleaching. The "dyeing" of chamois leather is generally done with ochres and similar colouring matters, and may be removed by washing. Treatment with egg-yolk in water, or with an emulsion of olive-oil with a little soap, and rubbing, or stretching, will restore softness to chamois leather which has become stiff by washing. CHAPTER XVIII. CROWN LEATHER, OR PRELLER'S LEATHER. The process of manufacture of this leather, which has obtained a firm position as the most suitable material for certain classes of belting, picker-straps, &c., was discovered about 35 years since by Theodor Klemm, a cabinet-maker in Wurtemburg and founder of the present well-known firm of leather manufacturers, Gebrüder Klemm of Pfullingen. Klemm, at that time in poor circumstances, sold his patent in Paris to an Englishman, Preller, who started a manufacture of it in Southwark and adopted a crown as his trade-mark. Since this time the manufacture has spread, first to Switzerland and then through Germany; but in England, to the writer's knowledge, it is confined to one or two firms.