On Tanning Leather. - Preparation of hides.

Scientific American 21, 9.2.1850

For the Scientific American.

(Continued from page 160.)

Tawing, currying, and Leather Dressing.

Currying Leather.

The common mode of currying leather for shoes, booths, &c., consists in first softeing the hides, as they come from the tan-pit, by soaking them thoroughly in water; they are then placed on a polished beam with the flesh side outwards, and pared with a broad sharp knife, till all the inequalities are removed and it is reduced to the required thinness. They are then again rubbed and washed with a polished stone and, while still wet, are besmeared with currier's oil, generally fish oil, or a mixture of this with tallow, which renders them much more impervious to moisture, and proper to protect the feet against the inclemency of the weather. - They are afterwads hung up to dry, by which the moisture is evaporated, but the oil, which cannot be dissipated by more exposure, gradually takes the place of the miusture, and penetrates deeply into the pores of the leather. It is then dried either in the sun or in a stoved room.

Blackening the leather is also a part of the currier's business, which is done on the grain side simply y rubbing it with an iron liquor, but on the flesh side with a mixture of lampblack and oil.

Common boot leather, as usually prepared, is, however, still, in some degree, pervious to water, by long exposure towet, and for this reason fishermen, wild-fowl shooters, and those whose employment or amusement leads them to be long on wet ground, usually preare their boots with an additional dressing of some oily or viscous matter.

Shammoyed Leather.

This is generallly prepared from sheep or does' skin prepared in the way already mentioned, by dressing, liming, &c., and dyed if necessary, and then finished with oil. This forms the common wash leather, breeches leather, &c., and is the only kind which, when dyed, will bear washing without the coloring being materially injured.

We add the following particulars relative to the manufacture of some of the most remarkable kinds of leather prepared in foreign countries, which although in mostr respects closey resembling ours, have distinct points of difference.

Real Morocco Leather.

The process for the reparation of this leather from the goat-skins at Fez and Tetuan, is thus described by M. Broussonet: - The skins are first cleansed, the hair is taken off, limed, and reduced with bran, nearly in the way already described for the English Morocco leather. - After coming from the bran they are thrown into a second bath, made of white figs, mices with water, which is thereby rendered fermentable, in which they remain four or five days, and they are then thoroughly salted with salgum (or rock salt) alone, in lieu of the salt and alum; after which they are fit to receive the dye, which, for the red, is cochineal and alum, and for the yellow pomegranate-bark and alum; the skins are then tanned, supplied with a little oil, and dressed.

Russia Leather.

Much excellent leather of every kind is prepared in different parts of the Russian Empire. The preparation of the fine Russian leather, so well known for its quality and for its peculiar smel, is described at large in Mr. Tooke's "View of the Russian Empire," to which we must refer the reader for the minutiæ of the processes. The hides are first put into a weak alkaline ley to loosen the hair, and then scraped on a beam; then (if calves) are reduced by dog's dung and a sour oatmeal drench, and tanned with great care and frequent handling; the bark used here is seldom oak, that of the black willow breing preferred; but if this cannot be obtained they use birch bark. They are then either dyed red or black, these being the two colors most esteemed. For the red the hide is first soaked in alum, and then dyed with Brazil wood, and the black is given as usual with an iron liquor. The leather is then smeared with birch bark, which gives the peculiar smell so much prized, and which, when used for book-binding, has the valuable property of protecting the book from worms. The streaked or barred surface is given to the leather by a very eavy steel cylinder wound round the wires.

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