Moulds are at the present day used in every branch of the art, from the lowest to the highest. Drain-pipes are made in a cylindrical mould, with a smaller and solid cylinder inside. The clay is pressed between the two concentric cylinders. In making earthen-ware, the clay is sometimes rolled out and spread upon a block of the desired shape. In making plates, the clay is spread over a round block, and moulded by a form pressed down from above. When plaster of Paris is used, the process is very like that described by Piccolpasso. The mould is in two parts, into each of which the clay is pressed. The two pieces are then brought together, and the seams joined. Or a plaster mould may be used, into which the paste is poured in a liquid state. The absorption of the liquid by the plaster soon gives the clay sufficient consistency to take the necessary shape. Subsequent shrinkage allows its removal from the mould. After a partial drying, the ware is dressed or “shaved.” The process is a very delicate one, especially in the finer kinds of ware, in which a finely polished surface is necessary. The piece is placed on a lathe, and cut to the necessary thickness, and receives its ornamental lines, or has the mouldings applied. The handles are then attached, and, after drying, the piece is ready for the kiln. The moulding of porcelain requires very great care, on account of the fragility of many of the pieces. In Japan, clay moulds were exclusively used until within the past three years. After being thrown or moulded, and slightly dried, the pieces are shaped by means of sharp metal instruments in the same lathe on which the throwing is done. A coat of pure white clay is then laid on for the purpose of enhancing the beauty and heightening the effect of the color. This having been done, the piece is ready for the preliminary firing. When large pieces are made, the European method is to pour the necessary thickness of slip over the inside of the mould, against the side of which it is kept by means of forcing air into the interior, after covering the surface, or exhausting the air through the mould. When sufficiently dry to support its own weight, the piece is fired. [Illustration: Fig. 23.--A Potter in Palestine.]