Porcelain

Porcelain. This substance, the name of which is derived from the Italian porcellana = "a shell," appears to have been completely unknown to the older European nations. It was, however, known to, and manufactured by, the Chinese at a very early period, and about the 16th century large quantities were introduced from China into Europe. It was not, however, until 1709 that its manufacture was performed in Europe, in which year Bottcher, a German chemist, having discovered the method of its preparation, started works at Meissen. For many years the process remained secret, but in 1754 the celebrated potteries at Sevres were founded, and at intervals other centres of the industry sprang up. The first places in England to carry out the porcelain manufacture were Chelsea and Bow, shortly followed by Derby and Worcester. In composition, porcelain consists chiefly of a very pure clay known as kaolin, which is almost pure hydrated silicate of alumina. This substance seems to be derived chiefly from the natural disintegration of the felspar of rocks. It is found largely in China, at Limoges, in Cornwall, and various American localities. It is very infusible, and for the manufacture of porcelain is mixed with a fusible silicate, usually felspar, the proportions of the two substances varying with the different varieties of the product. They are well mixed, and water added until of a sufficient plasticity; the mass is moulded to the required shape, and dried at ordinary temperatures, and baked in a low-temperature kiln. They are then glazed by dipping into water containing felspar in suspension, dried and exposed to a very extreme heat in crucibles in a furnace; after heating, the furnace is very slowly cooled, as otherwise the porcelain would be very unstable and brittle. Statuary porcelain is an unglazed porcelain, used chiefly for the production of statuettes, etc., and was introduced in the year 1842, being also frequently known by the name of Parian porcelain or Parian marble. Porcelain takes paint in very much the same way as glass, the pigments being applied and "burnt in" by heating the substance. [Glass.] The Sevres porcelain is considered to be the finest example of this branch of art, owing chiefly to the beauty, richness, and depths of the colours.