Pottery

( Fayence, Terraglia ), as distinct from porcelain, is formed of potter’s clay mixed with marl of argillaceous and calcareous nature, and sand, variously proportioned, and may be cla ed under two divisions: Soft (Fayence à pâte tendre), and Hard (Fayence à pâte dure), according to the nature of the composition or the degree of heat under which it has been fired in the kiln. What is known generally in England as earthenware is soft, while stone-ware, Queen’s ware, ., are hard. The characteristics of the soft wares are a paste or body which may be scratched with a knife or file, and fusibility generally at the heat of a porcelain furnace. These soft wares may be again divided into four subdivisions: unglazed, lustrous, glazed, or enamelled. Among the three first of these subdivisions may be arranged almost all the ancient pottery of Egypt, Greece, Etruria, and Rome; as also the larger portion of that in general use among all nations during med iæval and modern times. The glazed wares may be again divided into silicious or gla -glazed wares, and plumbeous or lead-glazed. In these subdivisions the foundation is in all cases the same. The mixed clay or “paste” or “body” is formed by the hand or on the wheel, or impre ed into moulds; then slowly dried and baked in a furnace or stove, after which, on cooling, it is in a state to receive the glaze. This is prepared by fusing sand or other silicious material with potash or soda to form a translucent gla , the composition of the glaze upon vitreous or gla -glazed wares. The addition of oxide of lead constitutes the glaze of plumbeous wares; and the further addition of the oxide of tin produces an enamel of an opaque white of great purity, which is the characteristic glazing of stanniferous or tin-glazed wares. Most of the principal seats of the manufacture of pottery, and a description of the objects manufactured, and methods used in the manufacture, will be found mentioned under their respective headings.