LIGHT LEATHER MANUFACTURE 93 



convenient to deal with the different classes of skins in 

 different sections. Just as the hides of ox and heifer were 

 much the most numerous and important of hides, so also 

 naturally are sheepskins the most prominent section of the 

 raw material of the light leather trade. This is the more 

 true because the skin is valued for its wool as well as for 

 its pelt ; indeed, the wool is often considered of primary 

 importance, and receives first consideration in fellmongering. 

 Unfortunately for the light leather trade, sheepskins, 

 though most numerous, do not give the best class of light 

 leather, the quality being easily surpassed in strength, 

 beauty and durability by the leather from goat or seal skins. 

 In the wet work for the preparation of skins for tannage 

 much the same general principles and methods are em- 

 bodied as in the case of hides, but with appropriate modifica- 

 tions. As soft leathers are chiefly wanted, a mellow liming 

 is quite the usual requirement for all skins. It is also 

 usual to have a long liming, for some skins (like those of 

 sheep and seal) have much natural fat which needs the 

 saponifying influence of lime and lipolytic action of the 

 enzymes of the lime liquors ; whilst other skins (like those 

 of goat and calf) are very close textured and need the 

 plumping action of the lime and a certain solution of inter- 

 fibrillar substance. In consequence of the long mellow 

 liming, sulphides are not usually necessary, and indeed 

 sodium sulphide is not usually desirable, on account of its 

 tendency to make the grain harsh. It is used, however, 

 for unwoolling sheepskins, in such a manner that the grain 

 is not touched. Similarly caustic soda is seldom required, 

 and the yield of pelt by weight is usually a small considera- 

 tion. Systems of liming show some variety. The one-pit 

 system is very common, and is less objectionable for a long 

 mellow liming, but rounds of several pits are also used, 

 and in some cases even more than one round. This is 

 obviously conducive to regularity of treatment, and as the 

 work involved in shifting the goods is much less laborious 

 than in the case of heavy ox hides, it would seem a prefer- 

 able alternative. The depilation of sheepskins involves 



