only colors that will stand the grand feu heats of hard porcelain are: blue from cobalt, red from copper and celadon green and brown from iron. These, therefore, are used under the glaze. In order to extend the range of colors on hard porcelain ware a sepa rate firing becomes necessary, either in an oven of less heat or exposed in parts of the incandescent oven which are not reached by the most intense temperature. Of such are turquoise blue from copper; purple from manganese; yellow from iron with a propor tion of antimony. Colors which will stand in kilns of lesser heat are red, from iron oxide; brown, from iron chromate or man ganese; green from copper; yellow from anti mony; rose and purple from gold.
History.— No industry furnishes a history so full of romance as that of porcelain. The discovery of the porcelain body was made in China; the first production having the char acteristics of translucence with vitrification would appear to have taken place at the end of the 6th century. The cause of its discovery is the great love and reverence of the Celestial for jadestone. Carved jade was, par excellence, the most valued of the Chinaman's possessions, and it was in the attempt to obtain a substance with the qualifications of this hard, semi-trans lucent, greenish-yellow mineral (nephrite) that kaolin was used for a body or mass, combined with other silicious material, and celadon was the outcome from which magnificent vases, bowls, etc., were produced. Celadon could not be called translucent. By the 7th century, at least, we know that at Changnanchin, called later Ching-te-chen, true porcelain was in course of manufacture in large quantities having the qualities of being translucid, stone-hard, reso nant and of vitreous fracture— the natives called it Tali to distinguish it from Wa, earthen ware. A description of the different lovely wares of the Chinese dynasties will be found elsewhere (see CHINESE CERAMICS). Already in the 16th century Chinese porcelain ware was becoming known in different parts of Europe as rare and lovely works of art of great value and Florence (under the Medici) attempted to make imitations, at the end of that century, of Chinese specimens in their possession. It was an artificial glassy porcelain made from im pure china-clay (Terra-Vicenza), fine white sand and powdered glass. With the growing admiration of Europeans for the Oriental porce lains and the increasing qumbers of superb collections among the royalty and nobility grew up an intense desire to produce the ware at home. The Jesuit priest, Pere d'Entrecolles, during his prolonged stay in China gathered a mass of information as to the methods of manufacture of the coveted ware and sent de tailed accounts home of his discoveries among the kilns of Ching-te-chen from 1712 to 1722. They did not bring about the discovery of materials for the porcelain body, however, though they assisted greatly in giving invalu able information on the Chinese methods of porcelain decoration. To meet the popular clamor for pieces of pottery similar to the Oriental porcelains at a cost within the reach of the bourgeoisie of wealth the lovely speci mens of blue-and-white underglaze and some polychrome pieces (see CHINESE CERAMICS) were reproduced in earthenware coated with a tin-glaze opaque white slip by the 17th-century Dutch potters at Delft. (See DELFT). In spite of diligent search, the clays which produce porcelain remain unknown. The Japanese
nation claims that its knowledge of art pottery was gained from the Koreans, but Chinese in fluence introduced porcelain manufacture to the realm of the Mikado. With the Japanese con noisseurs porcelain took a secondary apprecia tion and earthenware alone received their patronage. The peculiar decorative talents of these islanders produced clever porcelain styles that quickly attracted European attention and demand and the trading companies of Hol land and England were soon importing great quantities of Japanese alongside the Chinese wares. The porcelains of Japan are described fully elsewhere. See JAPANESE CERAMICS.
European While both Flor ence and Venice had produced pieces of art ware of porcelain appearance, these were but of glass body with admixture (perhaps) of ground Chinese porcelain fragments. Of recent years the honor of making porcelain ware in industrial quantity has been awarded to Rouen, where a good quality of ware was produced in an admirable soft porcelain body. In 1673 Edme Poterat (talented faience master) se cured a license to manufacture in his earthen ware works porcelain as well as faience. It was carried on till 1696 by Louis Poterat, a son, who when he died had never divulged the secret working formula. Several pieces of this rare ware are in Europe and America (Morgan collection). Pierre Chicaneau's por celain factory at Saint Cloud was active as early as 1670 and the letters of several con temporary notables testify to the fact that both in painted decoration and beauty of form and finish the ware fully equaled that of the Chinese. It continued in operation till 1766. A number of pieces are found in present-day collections proving the high quality of this ware, which, besides cups and saucers, includes tea-pots, milk jugs, candlesticks, spice-boxes, handles for knives and forks. The delicate relief work is remarkable, hut the pieces are rather thick. Johann Friedrich Banger, a German alchemist, was the first to make hard porcelain in Europe. His claims of power to turn base metal into gold caused Augustus 'II, Elector of Saxony, to hold him in captivity in preference to turn ing him over to the king of Prussia, who was anxious for him to carry out his proclaimed powers in Berlin. Mager, under the protec tion of the Elector, set up his furnace and laboratory in Dresden. But his failure to bring forth the precious metal caused him to he moved from place to place as a prisoner under associates of the king. After several attempts at escape his life was in danger from anger at his deceptions till he discovered the process of making a red stoneware of extreme hard ness which stood polishing on the lathe, much to the pleasure of the king, and by 1707 he was producing much of the ware for the courts. In 1709 Mager discovered kaolin in his neigh borhood (a barber is said to have been using the white powder on his wigs and told him whence the mineral was derived). His suc cess was so quick that large quarters for the making of his true porcelain ware became neces sary and he was transferred to Albrechtsburg Castle at Meissen. He died in 1719, but the factory and its ware became the most noted in Europe. The progress of the Meissen styles is one of extreme interest and is fully de scribed elsewhere (see DRESDEN PORCELAIN).