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„,aatiefactory 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, ao that the moisture may be uniformly distributed. It is then trodden on hurdles (Horden), composed of square bare of wood, joined corner to corner, so as to make a floor of sharply angular ridges, Fig.
922. The neat operation is atretobiug over a circular knife, called the Stollmond (stollen, Eng. " staking "), shown in Fig. 923 ; then the leather is dried nearly com pletely, and staked again.
Dyeing.—The dyeing of glove-kids is done in two ways : — a. The skins are plunged into the dye-bath (Tunkfarben). In this way, all light colours are ordi narily produced, such as gris per' (pearl-grey), pailM (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 (Baize), then with the dye-liquor, and lastly with a solution of a mineral salt. 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 akin which yet contain fat to take the colour evenly with the rest. To satisfy these condi tions, the composition of the mordants is very varied. Bichromate of potash, ammonia, potash, soda, and stale urine are among the most frequently employed, seldom separately, but usually in a mixture containing two or more.
Dyestuffs of vegetable origin have always held the first place. These most in use are logwood (Blauholz), Brazil-wood (Bothholz), the two fuatica —Cuba Gelbholz (Menus tinctoria) and Ungarisches Gelbholz (Rhus cotinus), several species of willow-bark and of berries, indigo-carmine, and indigo dissolved in sulphuric acid.
Aniline oolours 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 (Uebersteich) 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 " vitriola " 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 therefore require a second feeding (Nahrung) of egg-yolk and salt. In the ease 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 aide, either by hand or machine. They are then dyed on this aide, 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.
Bibliography.—C. Morflt,' The Arta of Tanning, Currying, and Leather-dressing' (Philadelphia : 1852); F. Dussauce, Tanning, Currying, and Leather-dressing' (Philadelphia : 1865); H. Villain, Cuirs et Peaux : Tannage, Corroyage, et Megisserie ' (Paris : 1867); C. Vincent, Fabrication at Commerce des Cnirs et Peaux ' (Paris : 1872); • Abridgments of Specifications : Skins, Hides and Leather, 1627-1866' (London : 1872); J. C. H. Lietzmann, Herstellung der Leder in ihren Chemischen and Physikaliachen Vorgiinzen ' (Berlin : 1875) ; J. S. Schultz, Leather Manufacture : a Dissertation on the Methods and Economics of Tanning ' (New York : 1876); W. Eitner, • Leder Industrie : „Bericht fiber die Welt-Ausstellung in Philadelphia, 1876 ' (Vienna : 1877); F. Wiener, Die Lohgerberei, oder die Fabrikation des Lohgaren Leders ' (Leipzig : 1879); ' Leather-trades Circular and Review' (London) ; Tanners' and Currier' Journal' (London); Scottish Leather Trader' (Glasgow); 'Shoe and Leather Reporter' (New York) ; 'La Halle aux Cuirs' (Paris); 'Der Gerber' (Vienna) ; Gerber-Zeitung ' (Berlin); 'Deutsche Gerber-Zeituug ' (Berlin).
(See Skins ; Tannin.) H. R. P.