74 ANIMAL PROTEINS 



for light harness, and an extra layer of 75 is given if the tanner 

 is not the currier also. Thus the usual tannage is 16-20 

 weeks, of which 10-14 weeks (63-73 per cent.) are in layers. 



Type 3 is a tannage which may consist of myrabs (55 per 

 cent.), valonia or mimosa bark 25 per cent., and extract (26 

 per cent.). The extract is chiefly quebracho, though some 

 chestnut may be used. More valonia and less myrabs may 

 be used if desired (and when possible), and myrabs extract 

 will then replace quebracho and chestnut. The goods are 

 coloured off in drums or paddles, and then pass through 

 two sets of suspenders handlers (20-55 and 55~75)- 

 They are handled up and down very frequently in the first 

 set and rapidly pass into stronger liquors. The backs then 

 receive three floaters at 80, in each of which they remain 

 one week. The tannage is completed by three layers : first, 

 85 for one week ; second, 90 for one week ; third, 95 for 

 two weeks. The tannage is thus n weeks, of which 7 weeks 

 involve little labour. If the tanner is not the currier, still 

 stronger liquors may be used. 



In all these tannages little or no acid is used for plumping, 

 as the natural acids of the liquors are sufficient to ensure 

 what is necessary in this direction for this class of leather. 

 A little organic acid or even boric acid may be used in the 

 earliest liquors for deliming purposes, when necessary. 

 After tanning the goods are dried out and sorted in the 

 rough state. Harness is a somewhat broad term, and 

 there is scope for considerable variety in classification. The 

 hides are sometimes not rounded until after tanning. The 

 finished article may be any grade between heavy harness 

 for artillery and leather for ordinary bridles. 



In currying heavy black harness, the backs are soaked 

 and sammed for shaving. I/ighter goods may be machine- 

 shaved, but the heaviest are shaved lightly by hand over 

 the beam or merely " skived " with the shaving slickers. 

 The neck needs most attention, and it is often advisable to 

 stone by machine and split. The scouring should be 

 thorough, on flesh and grain. This is done by machine, and 

 not only cleans the goods from bloom, dirt and superfluous 



