Some of the more costly kinds of paper-hangings have gold as one of the materials forming the device. This is effected by using a wash of gold powder, instead of a pigment, on one of the carved blocks. There are also _washable_ paper-hangings, in which the surface is of a glossy or varnished nature, by which it may be washed free from dirt and grease without removing the colours with which the paper is printed. There is likewise a kind of paper-hangings called _flock_ paper, which has been much in use, and of which the following description has been given. The flock is woollen cloth reduced to great fineness, and laid on with varnish. After the coloured portions of the paper are finished, a carved block representing the device which is to be flocked, is laid down on a flat place coated with wet varnish, and an impression of the varnish is transferred to the paper, just as if it had been a coloured pigment. A quantity of the powdered flock is then strewed over the whole paper, and pressed on it by a flat board, a roller, or some other convenient means. The paper is then left to dry, after which the dry flock is brushed off from those parts where no varnish had been applied, leaving an appearance much resembling that of coarse woollen cloth, which our readers may frequently have noticed. The flock is prepared in various ways. Sometimes pieces of woollen cloth of the proper colour are taken, and chopped up by means of a bill or knife; but this is a rude and imperfect way, now probably out of use. Another mode is, to place the pieces of cloth in a flat box, and cause a sharp knife, moved by machinery, to pass rapidly, with a chopping motion in every direction over the various pieces of cloth. In some cases, also, the cloth is reduced to flock by a kind of grinding process. The Process of Paper-hanging. This, then, is an outline of the mode by which paper-hangings are prepared; and we must next speak of the method of pasting them against the walls of a room. As the long pieces or strips of paper do not average more than two feet in width, it is obvious that a great many joints must be made in covering the side of a room with paper. These joints proceed not crosswise, but perpendicularly from the ceiling downwards; and considerable care is necessary to insure the continuance of the pattern on the two sides of a joint: it is in this that the principal art of the paper-hanger consists.