CHROME LEATHER MANUFACTURE 155 



albumen, gelatine, starch, egg yolk in addition to soap 

 and oil. Soda and borax also assist, and degras and sod 

 oil are also useful and are admissible where the leather is 

 to receive a dull finish. The operation of fat liquoring is 

 greatly assisted by heat, and temperatures of about 110 

 to 130 F. are usual. Chrome leather may be dyed before 

 or after fat liquoring : if before, the fat liquor' sometimes 

 tends to alter the shade ; if after, the dyeing tends to be 

 uneven. lyOgwood extract and iron salts are largely used 

 for blacks. It is common to mordant chrome leather with 

 vegetable tanning before dyeing. Sumach and gambier 

 are often used for this purpose, and the usual " fixing 

 agents " (tartar emetic, titanium salts, etc.) may also be 

 used. 



Of the mechanical finishing operations staking is the 

 most characteristic. It is now done entirely by machines, 

 and the primary purpose is to soften the leather, which 

 otherwise dries out in a non-pliant and stiff condition. 

 In the staking machine, the " blade " is fixed between 

 two rollers, which are however on the other side of the 

 leather. The leather is held by the operator, and the 

 machine " head " pulls a fold of the leather over the blade. 

 Seasoning and glazing are also common for many chrome 

 leathers. 



REFERENCES. 



Procter, "Principles of Leather Manufacture," pp. 198-220. 

 Bennett, "Manufacture of Leather," pp. 210, 312, 355, 375. 

 Bennett, "Types of Two-bath Chrome Tannage," Leather, 1909, 

 Aug. and Sept. 



