The peculiar beauty and translucency of fine porcelain, is due to an excess of silica, or the vitreous element of pottery, in its composition. This is attained by the use of kaolin, a fine, white clay, produced through the agency of natural causes in the decomposition of feldspar, which is itself a silicate of alumina, and one of the principal ingredients of granitic rocks. In porcelain, it may be said, that the proportion of silica to alumina is about three to one, and the other ingredients, such as iron, potash, chalk, and soda, exist only in such quantities as are necessary to cause the fusion of the two first-mentioned elements. It is fired but slightly the first time. This leaves the body of the ware very soft and porous, and upon the application of the glaze the latter is absorbed into the body, and by its action upon the materials composing it, produces a translucent effect. We refer, here, to French porcelain. In the manufacture of English china, the process is radically different. The last-mentioned ware is sometime spoken of as “bone china.” This term has reference to the use of bones from which the lime required in its manufacture is obtained. This element produces a translucent quality in the body of the ware independently of the action of the glaze, which in this case forms merely a coating upon the surface of the previously hard baked body. Earthenware possesses less of the vitreous element, and the first firing is continued until the ware becomes so dense that it will not absorb the glaze, and the body remains opaque. The term pottery, is more strictly applicable to the kind of ware last mentioned. It is to this that especial reference will be made in the following pages, in describing methods of manufacture and decoration. Earthenware is of various colors, ranging from pure white, through the cream white and cream-colored wares to decided yellow, and lastly red. The clays can also be artificially colored, and changes in color are also produced by different degrees of temperature in firing. Ordinarily the process of firing produces a material change in the color of clay. Thus, a grey-tinted clay will assume a bright, yellow color, and a dull brown, green, or blue will be changed to a bright brick-red, under the action of the fire. The heat used in firing should produce partial vitrification. If a piece of ware has not been fired sufficiently to produce that effect, it is said to be “soft-baked.”