It requires several days and sometimes weeks to effect these several objects, by the use of lime alone. Moreover, lime being nearly insoluble, the hides become impregnated therewith, so that bates and drenches and much labor are required to remove it, before the hides are in a suitable condition to receive the tannin, in consequence of which, their muscular fibre and texture are materially injured. But potash being very soluble, is easily washed or worked out by water alone; besides, it has a greater affinity for fat or oil, and makes a soluble soap, which is also easily worked out; but lime makes an insoluble soap, which is removed with more difficulty; potash being soluble, penetrates and softens the hide more speedily, and thus enables the lime itself to act sooner than it could alone. But fresh quick lime loosens hair sooner than potash. Thus the two conjoined, subserve a better purpose than either singly. Salt, in solution, also aids in softening dry or hard hides. It protects the substance of the hide from the too caustic action of the alkalies—loosens dirt, grease, &c., and thereby purifies the skin. It might be omitted in treating salted hides unless soaked too long in water. But in all cases it preserves the substance and weight of the hides, while undergoing the liming process. Second, the nature of Hibbard’s invention, so far as it relates to the process of tanning, consists in the use of a composition of salt, sulphuric acid, and sumac, oak, hemlock bark, or any other tannin used for tanning. The salt, sulphuric acid, and tannin being mixed together in water, in certain proportions hereafter mentioned, a portion of the salt is decomposed by the sulphuric acid, forming sulphate of soda and setting the muriatic acid free, which (the muriatic acid) being absorbed by the water acts directly and rapidly on whatever of the alkalies may yet remain in the skins, dissolving and removing them, while it acts with equal rapidity on the hide itself, “raising it,” or opening its pores, prepares it to receive the tannin, which, being present also in the mixture, immediately unites with the gelatine of the hide, forming leather more expeditiously than by the old method. To enable others skilled in the art of tanning to use this method, let them observe the following: For unhairing and liming, so called, and for pulling wool, prepare and use the following composition, which we denominate— Composition No. 1.—Good wood ashes, 1 bushel (or potash about 5 pounds); fresh slaked lime 4 quarts; salt about 3 quarts; water about 100 gallons. These ingredients may be mixed together and the hides be put into the mixture, for unhairing and liming. But for pulling wool, take lime and ashes equal parts, and salt 1 quart, to one bushel of the mixture and mix with water sufficient to make a thin paste, which is to be applied to the flesh sides of the skins in the usual way, and kept at a temperature of 60° to 68° F.