We all know that leather is the skins of animals, dressed and prepared for our use by tanning, or some other process, which preserves them from rotting and renders them pliable and tough.

The larger and heavier skins, such as those of buffaloes, bulls, oxen, horses and cows, are called “hides;” while those of the smaller animals, such as calves, sheep, pigs and goats, are called “skins.”

The tanning of raw hides taken from animals is an ancient trade. The bark of trees made into a liquor has been used for centuries in treating practically all kinds of hides.

The oak, fir, hemlock and sumach are the most familiar of the many trees from which “tannin” is obtained for this purpose.

The cow hide is used practically altogether for sole leather and is bark tanned in the majority of cases. After the hide is taken from the animal it is either dry cured, or else salted green, and packed for shipment or storage.

The first process of preparing sole leather is to cut these hides in half or sides. The sides are then run through lime vats for the purpose of loosening the hair. They are then run through the unhairing machine, in which large rollers remove the hair.

From the unhairing machine the hides pass to a fleshing machine, which cuts away all the flesh or fat on the hide. They are then trimmed and scraped by hand, after which the real tanning process begins.

The old method of tanning leather was in large vats, which were filled alternately with tan bark and hides, then filled with water and allowed to soak for a period of eight to nine months before the tanning process was complete. The extract of bark in liquor form is used today by all large tanneries.

After the hides have been all prepared for tanning they are hung on rockers in the tanning vats, where they are kept in motion both day and night so that all parts of every hide are equally tanned. They are changed from time to time from weaker into stronger liquor until the tanning process is complete.

All sole leather is filled more or less to make it wear the better.

The drying process comes next. The hides are all hung in a dry loft, where artificial heat of different temperatures is used until they are thoroughly dry. The drying of the hide is as important as the tanning. Hides that are dried too quickly become brittle, so that great care must be taken in this drying process. Even the weather conditions play an important part.

After the hides are thoroughly dried they are then oiled and ironed by large rollers having several hundred pounds pressure. This gives the grain side of the leather a finished appearance and also serves to press the leather together compactly.

Before this leather can be cut into sole leather it has to be again dried and properly edged to secure the best results.

Bark-tanned leather that is used for upper stock in shoes is tanned practically the same way as the bark sole leather, except lighter hides are used and the finishing processes are of a nature to make it softer and smoother.

The above tannage is what is called vegetable tannage. There is also a tannage made from minerals that is called chrome. This is used mostly in tanning soft, glovey upper leather, which when finished makes a very tough yet soft and pliable leather for footwear.

Ninety to one hundred days are required to tan bark leathers, while the chrome tannage is very quick and on the average requires only about three weeks.

The brilliant smooth surface of patent, enameled, lacquered, varnished or japanned leather is due to the mode of finishing by stretching the tanned hides on wooden frames and applying successive coats of varnish, each coat being dried and rubbed smooth with pumice stone. There is also a process called “tawing,” which is employed chiefly in the preparation of the skins of sheep, lambs, goats and kids. In this process the skins are steeped in a bath of alum, salt and other substances, and they are also sometimes soaked in fish-oil. The more delicate leathers are treated in this manner, those especially which are used for wash-leathers, kid gloves, etc.

In currying leather for shoes the leather is first soaked in water until it is thoroughly wet; then the flesh side is shaved to a proper surface with a knife of peculiar construction, rectangular in form with two handles and a double edge. The leather is then thrown into the water again, scoured upon a stone till the white substance called “bloom” is forced out, then rubbed with a greasy substance and hung up to dry. When thoroughly dry it is grained with a toothed instrument on the flesh side and bruised on the grain or hair side for the purpose of softening the leather. A further process of paring and graining makes it ready for waxing or coloring, in which oil and lampblack are used on the flesh side. It is then sized, dried and tallowed. In the process the leather is made smooth, lustrous, supple and waterproof.

What is a “Glass Snake”?

“Glass snake” is the name which has been given to a lizard resembling a serpent in form and reaching a length of three feet.

The joints of the tail are not connected by caudal muscles, hence it is extremely brittle, and one or more of the joints break off when the animal is even slightly irritated.