LEATHER, 89 



The Russians have long been possessed of a method of making a peculiar leather, 

 called by them Jucten, dyed red with the aromatic saunders wood. This article 

 has been much sought after, on account of not being subject to mould in damp 

 situations, being proof against insects, and even repelling them from the vicinity 

 by its odour. The skins are freed from the hair or fleece, by steeping in an ash-lye too 

 weak to act upon the animal fibres. They are then rinsed, fulled for a longer or shorter 

 time according to their nature, and fermented in a proper steep, after having been 

 washed in hot water. They are taken out at the end of a week, but they may 

 be steeped a second time if deemed necessary, to open their pores. They are now 

 cleaned by working them at the horse on both the flesh and grain sides. 



A paste is next composed, for 200 skins, of 38 Ibs. of rye-flour, which is set to 

 ferment with leaven. This dough is worked up with a sufficient quantity of water to 

 form a bath for the skins, in which they are soaked for 48 hours ; they are then trans- 

 ferred into small tubs, where they remain during fifteen days, after which they are 

 washed at the river. These operations serve to prepare the skins for absorbing the 

 astringent juices with uniformity. A decoction of willow-bark (Salix cinerea and Salix 

 caprca) being made, the skins are immersed in the boiler whenever the temperature of 

 the liquor is sufficiently lowered not to injure the animal fibres, and handled and 

 pressed for half an hour. This manipulation is repeated twice daily during the 

 period of a week. The tanning infusion is then renewed, and applied to the same 

 skins for another week ; after which, being exposed to the air to dry, they are ready 

 for being dyed, and then curried with the empyreumatic oil of the bark of the birch 

 tree. To this substance the Russia leather owes its peculiarities. Many modes have 

 been prescribed for preparing it ; but the following is the one practised in Russia. 



The whitish membranous epidermis of the birch, stripped of all woody parts, is in- 

 troduced into an iron boiler, which, when stuffed full, is covered tight with a vaulted 

 iron lid, having a pipe rising from its centre. A second boiler into which this pipe 

 passes without reaching its bottom, is set over the first, and is luted to it at the edges, 

 after the two are bolted together. They are then inverted, so that the upper one con- 

 tains the birch-bark. The under half of this apparatus is sunk in the earth, the surface 

 of the upper boiler is coated over with a clay lute, then surrounded with a fire of wood, 

 and exposed to a red heat, till the distillation be completed. This operation, though 

 rude in appearance, and wasteful of wood, answers its purpose perfectly well. The iron 

 cylinder apparatus used in Britain for distilling wood-vinegar would, however, be 

 much more convenient and productive. When the above bodies are unluted, there is 

 found in the upper one a very light powder of charcoal, and in the under one, which 

 served as a receiver, there is an oily, brown, empyreumatic fluid, of a very strong 

 smell, which is mixed with the tar, and which floats over a small quantity of crude 

 vinegar. The former matter is the oil employed to impregnate the skins, by working 

 it into the flesh side with the currier's tools. It is difficult to make this oil penetrate 

 with uniformity ; and the Russians do not always succeed in this process, for they 

 turn out many skins in a spotted state. This oil is at present obtained in France by 

 distilling the birch-bark in copper stills, and condensing the products by means of a 

 pipe plunged in cold water. About 60 per cent, of the weight of the bark is extracted. 



The skins imbibe this oil most equally before they are fully dry. Care must be 

 taken not to apply too much of it, for fear of its passing through and staining the 

 grain side of the leather. Chevreul has investigated the chemical nature of this odo- 

 riferous substance, and finding it to be a peculiar compound, has called it betuline. 



In the Franklin Institute for February 1843, Mr. Gideon Lee has published some 

 judicious observations on the process of tanning. Ho believes that much of the 

 original gelatine of the hides is never combined with the tannin, but is wasted ; for 

 he thinks that 100 Ibs. of perfectly dry hide, when cleaned from extraneous matter, 

 should, on chemical principles, afford at least 180 Ibs. of leather. The usual 

 preparation of the hide for tanning he believes to be a wasteful process. In the 

 liming and bating, or the unhairing and the cleansing, the general plan is first to steep 

 the hides in milk of lime for one, two, or three weeks, according to the weather and 

 texture of the skin, until the hair and epidermis be so loosened as to be readily re- 

 moved by rubbing down, by means of a knife, upon a beam or block. Another mode 

 is to suspend the hides in a close chamber, heated slightly by a smouldering fire, till 

 the epidermis gets loosened by incipient putrefaction. A third process, called sweat- 

 ing, used in Germany, consists in laying the hides in a pack or pile, covered with tan, 

 to promote fermentative heat, and to loosen the epidermis and hairs. These plans, 

 especially the two latter, are apt to injure the quality of the hides. 



_The bate consists in steeping the haired hides in a solution of pigeons' dung, con- 

 taining, Mr. Lee says, muriate of ammonia, muriate of soda, &c. ; but most probably 

 phosphates of ammonia and lime, with urate of ammonia, and very fermentable animal 

 matter. The dry hides are often subjected first of all to the operation of the fulling- 



