The process of manufacturing " chamois " or "shammy " leather is thus described by Dr. Ballard: - After the "pelts" have been fleshed and split, the inner or flesh sidesare taken for the manufacture. This portion is again passed through the splitting-machine in order to take off from the thicker parts so much as may suffice to render the skin of uniform thickness throughout. It is again limed, then washed, and afterwards put into a bran drench. After removal from the drench, the skins are pressed nearly dry, and then removed in bulk to the stocks, where they are beaten until they are soft with heavy tilt-hammers. When soft, oil (cod-liver oil in preference) is sprinkled on them, and the " stocking " is continued, oil being added from time to time. The skins are then taken out and "aired-off," i.e. hung up in the room to dry. At works where there is a sufficient open space adjoining, the skins are in dry weather hung out in the open air. This " stocking" and "airing-ofF " are twice repeated, and the skins are then hung up in a chamber heated to about 120° F. (49° C.) by hot-air or steam pipes. An offensive vapour of acrolein becomes thus diffused in the chamber.
When the skins are dry, they are " stocked " with oil again, and the beating is continued until the mass of skins becomes hot. They are then taken out, packed into a cask, covered over with blankets, and left to "ferment." The contents of the cask become very hot, and an abundance of vapour of acrolein is given off. After the fermentation has continued for a time, the skins are turned over and transferred to another cask. During this process, acrolein vapour is largely ovolved, and affects very greatly the eyes of the workmen. The fermentation is continued until heat ceases to be generated, and then the skins are allowed to get cold. The next thing is to get the oil out. With this object, the skins are thrown into hot water, and thence transferred to a powerful press. After leaving the press, they are put into a "tumbler," or revolving barrel, with warm water and soda-ash, and subsequently washed with cold water. Lastly, they are passed between rollers to press out all remnants of moisture and soapy matters, and hung up in a loft to dry. The further processes consist of various manipulations of scraping, pulling, stretching, etc., for the preparation of a saleable article.
The oil pressed out of the fermented skins is known as "sod oil." Before leaving the premises, it is customary to boil it in a pan heated by close steam, in order to drive off any water it may contain. It is then sent away for use by curriers.