GLOVE-KID.

This branch of leather manufacture is mainly carried on in Germany, Austria, and France. In Germany and Austria, lamb-skins are principally employed; in France, kid-skins. For fine gloves, the skins of very young animals only can be used. The ordinary style of manufacture is as follows:—The soaking of the dried skins is effected in large wooden tubs (Kufen, Bottichen), and occupies on the average 3-4 days, according to the character of the soak-water, the size of the skins, and the time they have been stored. The skins, when thoroughly and uniformly softened, are unhaired, either by painting the flesh-side with a thin paste of lime, or in lime-pits. In unhairing by painting (SchwÖden), the skins, after coating the flesh-side with lime, are folded together, so that the lime comes as little as possible into contact with the wool, and these bundles or "cushions" are placed in a tub, in which they are most frequently covered with water. After unhairing on the beam with a blunt knife, the skins must be limed for some days, in order that the leather may stretch well, a quality which the Germans denominate Zug. By this method of unhairing, the wool is preserved uninjured, but it is not suitable for the finer sorts of leather. The unhairing in lime-pits is done either with gas-lime (GrÜnkalk), or, as is now almost exclusively the practice, with the so-called "poison-limes" (GiftÄscher). These are prepared by mixing red arsenic (arsenic sulphide) with lime, while it is being slaked, and is at its hottest. The calcic sulphydrate (and perhaps sulpharsenite) thus formed hastens the unhairing, and gives the grain a higher gloss. Well-conducted establishments now avoid as much as possible the use of old limes, which produce a loose, porous leather, with a rough, dull grain. The liming lasts on the average 10 days, and is of the greatest importance. It is essential that the interfibrillary substance shall be dissolved, that the leather may have the quality known as Stand, that is to say, may be strongly stretched in either length or breadth without springing back. It also depends upon the liming (and this is of special importance in the case of lamb-skins), whether the tissue of the fat-glands is well loosened, so that the fat, either as such, or as lime- or ammonia-soap, may be readily and completely worked out. Skins in which this is neglected can never be properly dyed.

When the hair (or wool) is well loosened, the skins are rinsed in water, and then unhaired on the beam with a blunt knife. The water employed in washing should not be much colder than the limes, or it will prevent the hair from coming away readily. The wool or hair is washed and dried for sale. The skins are thrown into water, to which a little lime-liquor has been added, to prevent precipitation of the lime in the skins by the free carbonic acid of the water, which would have the effect of making them rough-grained.

Next comes the first fleshing (Vergleichen) or "levelling." By this, the loose cellular tissue on the flesh-side is removed, together with the head, ears, and shanks, and the flanks are trimmed. The skins are then again thrown into water, softened with lime-liquor as above described, and then into a bate of dogs' dung. This is prepared by stirring up white and putrid dogs' dung with boiling water, and straining it through a sieve or wicker basket. The bate must be used tepid, and not too strong. The skins "fall" (lose their plumpness) in it rapidly, and become extremely soft and fine to the touch; and the fat-glands, remaining hairs, and other dirt, can now be very readily scudded out. So far no completely satisfactory substitute has been found for this somewhat disgusting mixture, but it has been noted that guano will produce similar effects. With regard to the mode of action of the dung bate, much has been speculated without proof, and exact analytical evidence is wanting; but, no doubt, a weak putrefactive action goes on, as may be deduced from the presence of bacteria; further, the ammonia and weak organic acids present in the putrefying dung are capable of acting on fat and lime; and finally, a direct mechanical effect seems to be produced, difficult to describe, but favourable to the succeeding manipulation. Too strong bates, or too long continuance in them, produces evident putrefactive effects on the skins. (See also p. 184.)

When the skins come out of the bate, they are stretched and worked (abgezogen) on the flesh with a sharp knife, and any remaining subcutaneous tissue is removed. This constitutes the second fleshing. They are then rinsed in warm water, and beaten with clubs (Stoss-keule), see Plates 3 and 4, in a tub, or worked in a tumbler-drum (Walkfass), in either case with a very little water only; and finally brought into a tank of water, not too cold, and kept in constant motion with a paddle-wheel.

The skins are next cleansed on the grain-side by working on the beam with plates of vulcanite with wooden handles, so as to remove fat, lime- and ammonia-soaps, and other lime compounds, together with all remaining hair or wool. The skins are now a second time washed in the "paddle-tumbler," first in cold, and then in tepid water; and after allowing the water to drain from them, they are transferred to the bran drench.

This is prepared by soaking wheaten bran in cold water, diluting with warm water, and straining the extract through a fine hair-sieve. Sufficient of the liquid must be employed to well cover the skins, and the temperature may range from 50° F. (10° C.) to 68° F. (20° C.). These conditions are favourable to bacterial activity, which comes into play, and, on the one hand, evolves formic, acetic, lactic, and butyric acids, which dissolve any remaining traces of lime, and on the other, loosens and differentiates the hide tissue, so as to fit it to absorb the tawing solution (Gare). Much care is required in the management of the bran drench, especially in summer, since the lactic readily passes into the butyric fermentation (see also p. 186). The tawing mixture is composed (like that employed in the fabrication of calf-kid, q. v.) of alum, salt, flour, and egg-yolks, in a quite thin paste. The skins are either trodden in it with the feet, or put into a tumbler-drum with it (Fig. 48). Kathreiner pointed out, some years since (in vol. i. of 'Der Gerber'), that a mixture of olive-oil and glycerine might be partially substituted for the egg-yolks, in both the tanning and dyeing of glove-kid leather.

The tawed skins are now dried by hanging on poles, grain inwards. Rapid drying in well-ventilated, but only moderately-heated, rooms is essential to the manufacture of a satisfactory product.

The dry leather is rapidly passed through tepid water, and after being hung for a very short time, to allow the water to drain off, is trodden tightly into chests, and allowed to remain in them for about 12 hours, so that the moisture may be uniformly distributed. It is then trodden on hurdles (Horden), composed of square bars of wood, joined corner to corner, so as to make a floor of sharply angular ridges, Fig. 59. The next operation is stretching over a circular knife, called the Stollmond (stollen, Eng. "staking"), shown in Fig. 60; then the leather is dried nearly completely, and staked again.

Dyeing.

The dyeing of glove-kids is done in 2 ways:—a. The skins are plunged into the dye-bath (Tunkfarben). In this way, all light colours are ordinarily produced, such as gris-perle (pearl-grey), paillÉ (straw-yellow), chamois (reddish yellow), silver-grey, aquamarine, &c. b. The skins are spread on an inclined or rounded table of stone or metal, and brushed over, on the grain side, first with a mordant (Beize), then with the dye-liquor, and lastly, with a solution of a mineral salt (Plate 7). The mordant serves to fix the colour on the surface of the skin, to prevent its striking through, to produce certain modifications of colour, and to enable any parts of the skin which yet contain fat to take the colour evenly with the rest. To satisfy these conditions, the composition of the mordants is very varied. Potash bichromate, ammonia, potash, soda, and stale urine are among the most frequently employed, seldom separately, but usually in a mixture containing 2 or more.

Dye-stuffs of vegetable origin have always held the first place. Those most in use are logwood (Blauholz), Brazilwood (Rothholz), the two fustics—Cuba Gelbholz (Morus tinctoria) and Ungarisches Gelbholz (Rhus cotinus), several species of willow-bark and of berries, indigo-carmine, and indigo dissolved in sulphuric acid.

Aniline colours used alone remained in fashion for a short time only, but are now usefully employed as top-colours (Ueberfarben), viz. brushed in very dilute solution over vegetable colours. In this way, particularly tasteful shades of green, violet, and marine-blue may be produced.

After the mordant has been applied once or twice, and the colour 3-6 times, a wash (Ueberstrich) containing some metallic salt is generally applied, with the object either of bringing out the special tone required, or of making the colour more lively and permanent. The so-called "vitriols" are mostly employed: "white vitriol" (zinc sulphate), "blue vitriol" (copper sulphate), "green vitriol" (iron sulphate), and occasionally other salts.

Before dyeing, the greater part of the flour, salt, and alum must be removed from the skins by washing with tepid water; and they therefore require a second feeding (Nahrung) of egg-yolk and salt. In the case of the skins which are dyed by plunging into the dye-vat (Tunkfarben), this is done after the dyeing is completed; in that of brush-dyeing, before the dyeing process.

After the dyeing, the skins, if dipped, are wrung out; if brush-dyed, sleeked out with a brass plate, to get rid of superfluous water. They are then dried in an airy room. Before staking (stretching), the skins are laid or hung in a damp cellar, or in moist saw-dust. They are staked twice: once damp, and once nearly dry.

Skins which are much damaged on the grain, or otherwise faulty, are smoothed with lump pumice on the flesh-side, either by hand or machine. They are then dyed on this side, mostly by dipping, but occasionally with the brush, in which case, the method described is slightly modified.

Indebtedness is acknowledged to F. Kathreiner, of Worms, and David Richardson, of Newcastle, for much information on the production of light leathers. The Plates 1 to 8 represent the works of Messrs. TrÉfousse et Cie., at Chaumont (Haute-Marne).