In 1706 it appears that a Prussian named Böttger, an apothecary's clerk, in danger of persecution as an alchemist, fled to Dresden for safety. The elector, believing or hoping that he knew the secret of making gold, sent for him, anxious to learn the secret, which Böttger denied that he possessed. The elector thought it best, nevertheless, to put him in charge, for safe-keeping, of his alchemist Tschirnhaus; and with him he worked on, seeking to discover the "philosopher's stone." That he did not discover--few have done so--but, in mixing clays and preparing crucibles, it so chanced that a hard and semi-vitreous pottery was produced, which at once excited attention and sharpened invention. Was it porcelain, or could it be worked into porcelain? From that day Böttger's whole thought and ingenuity were at work to produce porcelain; the philosopher's stone was forgotten, and he and Tschirnhaus worked at their new problem. While the character of Böttger does not bear careful inspection, there is no question that he was a keen, dexterous, and daring man. The picture we have of him indicates a man of executive force (Fig. 125). [Illustration: FIG. 125.--_Johann Friedrich Böttger._] In 1708 some ware was produced by him and Tschirnhaus which approached the characters of Oriental porcelain, but it was not white or translucent. A teapot of this ware in red unglazed, and one in black glazed, are in the valuable collection of W. C. Prime, Esq., of New York (Fig. 126, the two tall teapots on the right and left). This was not white, nor was it true, porcelain. In 1710, however, they succeeded in making white porcelain of an inferior quality; it was "thick and muddy." Nothing as yet was perfect. What they lacked was the two fine materials known to the Chinese as kaolin and pe-tun-tse. Kaolin is a native clay, the result of decayed feldspar. It is found in Europe at Aue in Saxony, near St.-Yrieix-la-Perche in France, in Cornwall in England, and in Delaware in America. Pe-tun-tse is a siliceous stone found in China, and in Cornwall, England, is known as a granite. This last melts at a lower heat, and a mixture of kaolin is essential to give strength and hardness to the work. Oriental china (and all true porcelain) has the quality of hardness, and, when held up to the light, of translucency. European porcelains are known as hard and soft, the _pâte dure_ and _pâte tendre_ of the French. The Dresden china is hard. [Illustration: FIG. 126.--_Dresden._]