SECTION V. SOLE LEATHER 



LEATHER for the soles of boots and shoes is a matter of 

 essential interest to all, and forms one of the best appreciated 

 applications of animal proteids to useful purposes. Methods 

 for its manufacture are as numerous as the factories producing 

 it, hence all that can be done is to describe broadly the 

 general method which is typical of our time, to classify the 

 many varieties into types, and to indicate the recent changes 

 and present tendencies. 



Sole leather is mainly manufactured from butt pelt, and 

 the great aim is to produce a firm, thick, waterproof and 

 smooth grained leather which will bend without cracking. 

 It must have a light tan colour to be saleable, and contain 

 as much weight as possible to be profitable. 



The modern mixed tannage of " sole butts "or " scoured 

 bends " generally utilizes ox-hides of the Scotch and English 

 markets, though salted Continentals and South Americans 

 are also employed. After the usual soaking a short and 

 sharp liming is given. The special aim in liming sole hides is 

 to obtain the maximum plumping effect with the minimum 

 loss of hide substance. Both these achievements are 

 necessary to obtain good weight. The limes should be 

 kept as clean as possible, which is best obtained by putting 

 clean hides into work. This reduces bacterial activity and 

 loss of hide substance. The " shortness " of the process is 

 attained by the use of sodium sulphide (from 2 to 16 ozs. 

 per hide of sulphide crystals), by which depilation may be 

 accomplished easily in about nine days. The amount of 

 sulphide should be increased somewhat in the short -hair 

 season and in cold weather. Some factories take up to about 

 12 days using less sulphide, whilst others will lime in about 

 a week by using the larger quantities. The amount of lime 



