Sole leather is also made nowadays by tanning the hides by the chrome or chemical process. This leather is very durable and pliable and is used on athletic and sporting shoes. It has a light green color and is much lighter in weight than the oak or hemlock leather.
Many kinds of hide are used for sole leather. This country does not produce nearly enough hides for the demand, and great quantities are imported from abroad, although most of the imported hides come from South America. Imported hides are divided into two general classes, dry hides and green-salted hides.
Dry hides are of two kinds, the dry “flint,” which are dried carefully after being taken from the animal and cured without salt. These generally make good leather, although if sunburnt, the leather is not strong. “Dry-salted hides” are salted and cured to a dry state. Dry hides of both kinds are used for hemlock leather only, although all hemlock leather is not made from dry hides.
Green-salted hides are used in making oak-tanned leather as well as hemlock, and those used by United States tanners come largely from domestic points; but there is a variable amount imported each year from abroad, principally from Europe and South America. Green-salted hides are of two general classes, those branded and those free of brands.
Cow and steer hides of the branded type are used by tanners of oak and union leather. Those not branded are used more largely for belting and upholstering leathers, a small part finding their way into hemlock leather.
Sole leather remnants, strictly speaking, include such a wide variety of items that it is difficult to cover them all. Few people, however, realize the big range of usefulness of this class of stock. While not exactly a by-product, remnants are often classed as such. Under the class of sole leather remnants are included sole leather offal, such as heads, bellies, shoulders, shanks, shins, men’s heeling, men’s half heeling, men’s and women’s three-and four-piece heeling, etc. Stock that cannot be used in the shoe business goes into the chemical and fertilizer trade, among other outlets. By a special acid process of burning this stock, ammonia is derived from it, which goes into fertilizer; and another by-product is sulphuric acid for the chemical trade. The amount of ammonia obtained is small, being about seven per cent of ammonia to a ton of sole leather scrap. This is mixed with fertilizer and sold mostly in the Southern States, and to a small extent in the West, there being a law in many of the Western States against the use of fertilizer made from leather products, on account of its low grade.
Sole Leather Offal
Showing bellies, shoulders, etc. [Page 35.]