[Illustration: Fig. 71.--Tower of Nankin.]
A material which is neither stone-ware nor porcelain, but resembles very fine pipe-clay, is used in making opium pipes. The bowl is enamelled, and decorated with flowers or other forms, and is not unfrequently almost perfect as a work of art. The Chinese _boccaro_ remains one of the finest specimens of a _grès_ known to ceramists, and far above any of the stone-wares of Europe. Some specimens are as perfect in their beauty as jewels. The paste is sometimes brown of a reddish tinge, sometimes a gray faintly colored with yellow. It is made into single pieces and services, occasionally of fantastic design. When covered with colored enamels, the _boccaro_ is at once so delicate and brilliant as to be likened to nothing but a gem.
[Illustration: Fig. 72.--Enamelled Bricks from the Tower of Nankin. (N. Y. Metropolitan Museum.)]
At a very early period the Chinese attained to that wonderful mastery of the secrets of color which made them the envy of the artists of all subsequent time, and has led to the adoption of certain of their colors as universal standards of beauty and excellence. Combined with the certainty of their operations in crackle, their skill in color led to many remarkable effects in wares, the precise nature of which cannot be defined. Upon a rich golden crackle, white-and-blue figures are occasionally imposed (Fig. 73). In some cases the enamels used for this super-ornamentation are so transparent that the cracks can be seen through them. Possibly the most curious kind is that in which the vase is encircled by bands of crackle, some coarse and irregular, alternating with others fine and regular, and divided by stamped zones of brown ferruginous paste. Both Japanese and Chinese place a very high value upon the ancient specimens, the priority in point of time being accorded to the light blue. Besides the colors already mentioned, turquoise-blue, yellow, and a bright red are found upon crackle, to the first of which a special value is attached. The fine crackle, called by the French _truité_, is most frequently applied to vases of pale and olive-green not otherwise decorated. One cannot look at the exquisite coloring of some of the rare old pieces, without being led to the conclusion that the Chinese placed a value upon their ceramic productions not more than commensurate with the artistic skill developed among them.