the horn, it is now of a uniform dark green color, and perfectly soft. This treatment renders the tissues more pervious to the action of acids, and will be better understood when we arrive at the operation of staining. But there are other means of pressure. Around the apartment were arranged one hundred and twenty iron screw-presses--levers of the second order, and differing only from a common vice in pressing under the screw after the manner of nut-crackers. They are fitted with steel dies, with a variety of engraved designs, and in these braid-combs, the outside coverings of pocket-combs and side-combs are pressed. We were shown a new impression on pocket-combs of the Crystal Palace. A man exerting his strength on one of these presses can produce a force of upwards of fifty tons. But however great, the pressure is still insufficient. The enormous demand for the cheap side-combs of hoof led to the application of hydraulic pressure. The two portions of the hoof, after being boiled a second time in a number of little troughs, with a steam-jet in each of them to preserve the necessary temperature, the excrescences still adhering are pared off. They are then transferred to an adjoining room, where sixteen hydraulic presses, are in operation; and here are subjected to a pressure of three hundred tons, with a degree of speed and precision that is astonishing. They come out of the press in the form of small, semi-transparent, rectangular plates, having on each side the rounded projection or beading observable on most side-combs. To illustrate the resistless force of this pressure, we were informed that the very steel dies which give shape to the hoof are soon crushed and worn out; and it was not without some nice calculation and experiment that the application of hydraulic pressure to the purpose was successfully attained. After having received the necessary formation by the various modes of pressing, the plates are laid aside to dry in a room where a high temperature is preserved by means of steam-pipes, and where they are also assorted into different sizes, and the edges squared with circular saws. The number of such plates, of shell, horn, and hoof, in stock at the time of our visit, was somewhere about four millions and a half.