To understand the composition of porcelain, it is necessary to bear in mind that it is a compound of kaolin and petuntse, the former of which is infusible, and the latter fusible at a high temperature. The former constitutes the body of the piece, the latter gives it its translucency. The word “kaolin” is derived from _Kaoling_, the name of a mountain near King-teh-chin, one of the great centres of the manufacture in China. Kaolin is simply the result of the decomposition of granitic rock, and silica and alumina are its chief ingredients. Petuntse is pure felspar. The conditions in which these materials are found in China may be briefly stated. They are either in the form of stone or sand, from which the unsuitable parts are removed by the action of water. When they are thrown into the water, the fine particles which do not sink are collected and dried. The paste, before being used, is again put into water and strained through a sieve, so that only the finest is preserved, and used in making porcelain. The materials are obtained from different parts of the country, and blended according to their respective qualities, as ascertained by the most systematic investigation and experiment. The European process is similar, the kaolin being first washed clear of all argillaceous impurity, and then mixed with felspar and silicious sand. Of the further similarity between the two, MM. Ebelman and Salvetat say: 1st. The kaolin and petuntse used in making paste for Chinese porcelain are chemically identical with the materials used in Europe. The Chinese kaolin is evidently disintegrated granite. Chemically, petuntse resembles the pegmatite of Limoges; mineralogically, it is to be classed with petrosilicious felspar. 2d. The mechanical preparation of the pastes of China and Europe is based upon similar methods. 3d. The Chinese paste is the more fusible of the two. 4th. The Chinese glaze is also the more fusible, on account of the addition of lime to the petuntse, which the French use pure. It may be added that the Dresden, Sèvres, and Limoges porcelains are baked at a higher temperature, and are harder than the Chinese. The basis of the natural pastes of Germany and France is 46.66 parts of silex, 40 of aluminous earth, and 13.33 alkaline earth, although the proportions vary, and the following may be nearer an average: Silex, 66; alumina, 30; potash, magnesia, and lime, 4. In the glaze the proportions are different, the silica largely preponderating: Silex, 73.4; alumina, 15.7; potash, lime, and magnesia, 10.9. The following table is given by M. A. Salvetat as the result of analyses made at different times by himself and others: