For sole-leather, the method recommended by Eitner is to dissolve 4-5 lb. of sulphide per gal. of water, making the solution into a thin paste (of soupy consistence) with lime or pipe-clay. This is spread liberally on the hair side of the hides, one man pouring it down the middle of the hide from a pail, while another, with a mop or cane broom, rubs it into every part. The hide is then folded into a cushion, and in 15-20 hours will be ready for unhairing, the hair being reduced to a paste. In the writer's experience, the concentrated solution here prescribed will completely destroy all hair wetted with it in 2-3 hours, and if left on longer, will produce bluish patches, and render the grain very tender. The hides should be thrown into water before unhairing, to enable them to plump, and to wash off the sulphide, which is very caustic, attacking the skin and nails of the workmen. There is no doubt that this process gives good weight, and tough and solid leather; but there are several difficulties attending its use. Unless the mopping is done with great care, it will fail to completely destroy the hair, and the patches of short hair left are very difficult to remove. The expense of the material and the loss of hair are also important considerations. The hides are rather difficult to flesh, unless previously plumped by a light liming, and it is necessary to swell them with acid or sour liquor in the tanhouse, as the sulphide has but little plumping effect. Another method, which is much cheaper in labour and easier in execution, is to suspend in a solution of sodium sulphide, containing 3/4 lb. a hide or upwards; the hide should unhair in 24 hours. Very weak solutions loosen the hair, without destroying it; but it is always weakened, as the specific action of the sulphides is on the hair itself. After or before unhairing, the hides may receive a light liming, to plump them, or lime may be added to the solution of sulphide, which by forming calcium sulphide, and liberating caustic soda, considerably increases the unhairing and plumping effect. The pit may be several times strengthened for successive packs, but the loosened hair must be fished out, or it will quickly spoil the solution. When hides have been suspended in sodium sulphide solution, the hair is very quickly loosened by a short liming. Squire, Claus, and J. Palmer have all taken out patents for the use of tank-waste as a depilatory. It consists of impure calcium sulphides, and when brought into the form of soluble sulphydrate, either by boiling in water, or by the oxidising action of the air, it will unhair hides. The conversion is, however, very imperfect in either case, and its action is uncertain and slow; while the iron present is apt to cause unsightly stains. It is probable that the weights obtained may somewhat exceed those by liming. Palmer employs sulphuric acid to plump the hide and remove stains, and then reduces it by a bate of whiting and water. He