The tannage of calfskins by the chrome processes for the manufacture of upper leathers is one of the most extensive branches of leather manufacture. The deservedly popular =box calf= is typical of these leathers, and the observations of this section are primarily applicable to it. A chrome-tanned calf skin, fat liquored and blacked, provides as suitable an upper leather as could be desired for ordinary boots. It is at once supple and durable. It is also sufficiently waterproof, but can be given a bright glazed finish. In regard to the wet work for chrome calf, the general principles and methods discussed in the previous section are much to the point. It is essential to avoid undue plumping and the loss of hide substance. The skins should be washed clean as soon as possible. Three fresh waters are desirable, the goods remaining only a short time in each. Salted skins need more time, but the liquors must be kept sweet. Drumming the skins in running water is very suitable for the first and last stages of soaking. The liming should be short but not "sharp," _i.e._ mellow sulphide limes are suitable, depilation being carried out after about 7 days. The one-pit system is usual, but two liquors may be given, the green goods being first inserted into a used liquor, and after handling reinserted into the same pit with a new lime liquor made up with lime, sulphide and a proportion of the old liquor. Scudding should be carefully done, as hair on the finished leather is very objectionable. In deliming it is essential to have the grain of the skins thoroughly relaxed and pulled down. The finished box calf should have a characteristic soft and silky feel, and this is only attained by procuring the inelastic pelt. It is not surprising that a light puering is a popular method for attaining this, but there is also a tendency to use artificial bates such as are made from ammonium chloride and pancreatin, together with organic acids, or non-swelling acids like boric acid. Drenching is also common after a preliminary deliming with acid. The skins may be half or two-thirds delimed with lactic acid, rinsed and drenched over night at 85° F. with 6 per cent. bran on the pelt weight. Less acid may be also used, in tepid water, and the drench made up with 10 per cent. bran and a little pea meal. It is very common to pickle the skins in 5 per cent. alum and 5 to 10 per cent. salt before tanning. This is often of doubtful advantage, but sometimes prevents drawn grain when the goods are moved rapidly into strong chrome liquors. This pickling is said to give fullness to the leather.