albumen, which much resembles the hide-fibres in composition, is like them preserved by the fats. For the modern process of manufacture, good, even and well-flayed hides are selected, and unhaired either by sweating, or by a very short liming, which must be assisted by rockers or some mechanical mode of moving the hides, so as to get them unhaired in the shortest possible time and with the least injury to the fibre. Sodium sulphide (see p. 147) may be employed with great advantage. The fleshing and scudding are performed as usual, according to the mode of unhairing adopted. The hides are then very commonly rounded, and the bellies tanned in the usual manner; but sometimes the whole hide is made into crown leather. As crown leather is naturally almost white, it is usual at this stage to colour the hide with bark or other liquors. As in this case simply colouring and not tanning of the grain is required, high-coloured liquors, made by steaming materials with much colour and little tannin, are preferable. For this purpose wood extracts, such as chestnut, quebracho, or oak-wood are said to be very suitable, and beech, pine or alder bark may also be used. In practice, chestnut and hemlock extracts, and occasionally cutch are employed; but the last named is not to be recommended. A chestnut liquor of 7-1/2° Tw. or 5° B. (34° Bark.), with constant handling or in a paddle-tumbler, will give a satisfactory colour and grain in 1-2 hours. This rapid colouring is preferable to the slower process, which occupies 24 hours in weaker liquors. If sweated, the hides are now plumped with sulphuric acid, but only to a very moderate extent. This process is best performed in a paddle-tumbler; about 3-1/2 oz. of sulphuric acid are required per hide, and a time of 6-12 hours according to the water employed. The liquor may be several times used, strengthened with the necessary quantity of acid. Limed hides do not require further swelling. The hides are washed through clean water, and hung up to dry somewhat.