CALF-KID.

Calf-kid is used for light upper-leather, and belongs to a different class from any yet described, being "tawed" instead of tanned. In this respect, and in most details of its manufacture, it resembles glove-kid.

The process is as follows. Selected calf-skins, dried or salted, are the raw material, and after a suitable softening in fresh water, are limed for 2-3 weeks, or till the hair goes easily. They are then unhaired and fleshed in the usual manner, pured with a bate of dogs' dung, scudded, and again cleansed with a bran drench. In Germany, the bran drench is used alone, and is composed of 33 lb. bran to 100 medium skins. Before use, the bran should, especially in summer, be well washed, to free it from adhering meal. The temperature of the drench should not exceed 100° F. (38° C.), and the skins should remain in for 8-10 hours. Lactic acid is produced by fermentation; this removes lime, and is itself neutralised by the products of putrid fermentation which succeeds it.

The tanning is accomplished in a drum with a mixture of alum and salt; and after drying, the skins are again moistened, and worked in the drum with a mixture of oil, flour, and egg-yolk. In the German method, these two operations are combined. Eitner, who has written a series of articles on the process, gives 40 lb. flour, 20 lb. alum, 9 lb. salt, 250 eggs, or about 1¹/₃ gal. of egg-yolk, ⁷/₈ pint (¹/₂ litre) of olive-oil, and 12-16 gal. water, as a suitable mixture. The skins are worked in a drum-tumbler (preferably a square one, see Plate 5) for 20 minutes, then allowed to rest 10 minutes, and this process is twice repeated. The temperature must not exceed 100° F. (38° C.), and it is said to be important that the drum should be ventilated by holes at the axis.

The skins are allowed to drain, are then rapidly dried at a temperature of 140°-160° F. (60°-71° C.), and, after "samming," or damping with cold water, are staked by drawing them to and fro over a blunt knife fixed on the top of a post (see Plate 6). They are then wetted down and shaved, either with the moon-knife or ordinary curriers' shaving-knife, and sometimes receive a second dressing of oil, flour, and egg, to soften them still further.

Dyeing black is accomplished either by brushing on a table, or by "ridging" or folding, grain-side outwards, and drawing quickly through baths of the mordant and colour. To prepare them for the colour, stale urine is generally employed. A deeper colour, and one less liable to strike through the skin, is obtained by adding ¹/₄ lb. potash bichromate to 4 gal. of urine, or the following mixture may be substituted with advantage, viz. ¹/₂ lb. Marseilles soap dissolved in boiling water, 5 or 6 egg-yolks added, and the whole made up to 4 gal. with water and ¹/₄ lb. potash bichromate. The colour used is infusion of logwood or its extract, or two-thirds logwood, which is best extracted by stale urine or old soak-liquor, with addition of a small quantity of soda (1 lb. to 25 lb. dye-wood). It is fixed and darkened by a wash of iron-liquor (1 of iron protosulphate in 75 of cold water). After being again dried, the skins are grounded with the moon-knife, and rubbed over on the grain with a composition containing oil, wax, &c., and are finally ironed with a flat-iron, to give them a fine and smooth surface. Eitner gives a recipe for the gloss:—1 lb. gum arabic, ¹/₂ lb. yellow wax, ¹/₂ lb. beef-tallow, ³/₄ lb. Marseilles soap, 2 lb. strong logwood infusion, and 1 gal. water. The water is brought to a boil in an earthen pot, and then the soap, wax, gum, and tallow are added successively, each being stirred till dissolved before adding the next, and lastly the logwood. After boiling for an hour, it is allowed to completely cool, being incessantly stirred during the whole process.