160 ANIMAL PROTEINS 



and also cut into two along the spine. The finished article 

 is sold as " box-sides." To yield the characteristic grain 

 pattern, the goods are frequently printed and embossed. 

 Even the flesh splits are sometimes made into box calf 

 imitations, some filling material being used and an artificial 

 grain pattern embossed. 



Willow calf typifies the chrome calf which is finished 

 in colours. The soaking, liming and deliming processes 

 are the same as for box calf. The tannage, however, is 

 generally by the two-bath process on account of the lighter 

 colour thereby obtained. This colour is largely due to 

 the deposition of sulphur in and on the leather in the 

 second bath. 



In one tanning process the skins are first pickled in 

 2 per cent, hydrochloric acid and 10 per cent. salt. They 

 are then drummed in solution containing 2 per cent. 

 dichr ornate (strength i in 60) for about half an hour. A 

 solution containing 4 per cent, dichromate, 3! per cent, 

 hydrochloric acid, and 5 per cent, salt is gradually added, 

 and the skins drummed until well struck through. They 

 are then horsed overnight and struck out and passed 

 through a " hypo dip/' a 2 per cent, solution of thio- 

 sulphate, and then into the reducing bath, which contains 

 10 per cent, of thiosulphate, to which 5 per cent, hydro- 

 chloric acid is added. 



Another process employs paddles instead of drums. 

 The chroming liquor is made up with 4^ per cent, chromic 

 acid and 10 per cent. salt. The bath is exhausted by 

 commencing the tannage of a succeeding pack. The skins 

 are reduced as in the last process. 



In another process the " acid " type of chroming bath 

 is used. The skins are paddled with a solution containing 

 5 per cent, dichromate, 5 per cent, hydrochloric acid, 2 

 per cent, aluminium sulphate, and 10 per cent. salt. In 

 the reducing bath 14 per cent, hypo and 4 per cent, hydro- 

 chloric acid are used. 



In yet another process the skins are pickled first in 

 5 per cent, aluminium sulphate, 7! per cent, salt, and 



