There are certain pieces of blue-and-white in which both Persian forms and Persian styles of decoration have been followed, and these introduce the general subject of Persian influence as felt in China. It first manifested itself as far back as the Siouen-te period (1426) of the Ming dynasty, and is further represented by pieces belonging to the sixteenth and seventeenth centuries. The most easily recognized are those in which the Persian form is adopted, although the paste alone would lead one to ascribe them to China, as it is invariably finer than anything known to have come from Persia. There is in Mr. Runkle’s collection a ewer decorated with flowers in light-blue, resembling that of Tch’aï porcelain, the famous “blue of the sky after rain.” Real examples of this old blue must needs be rare, since the porcelain, variously called Tch’aï, Tcheou, and Tchi-tsong, was, like the old white, valued, even in fragments, as highly as jewels. A second from the same collection is given on the following page (Fig. 91). The panels are black, the flower and border decoration are in pink, green, and yellow, and show the variety and execution distinctive of Chinese work. There are many pieces of the same class in which the artist has attempted to follow the Persian styles more closely, but even a slight examination can leave little doubt of their Chinese origin. In connection with the blue-and-white decoration may be mentioned the vases of sea-green céladon, in which panels of white are reserved. On these are figures of men and animals, landscapes or flowers, in blue. A favorite form, and one well suited to this style of decoration, is a square bottle or vase, the sides of which enable the artist to paint the design in blue upon the flat. [Illustration: Fig. 90.--Aster Decoration. Blue-and-white. (W. L. Andrews Coll.)] Of the other blues which were used as ground colors, one of the most famous is the turquoise obtained from copper. It has all the clear depth of the stone from which it takes its name, a liquid transparency elsewhere unequalled. It appears on a great variety of pieces--gods, kylins, birds, dogs, and vases. The latter are very often graved in the paste, after designs more or less ornate. In the specimen given (Fig. 92), which is very finely crackled, the leaves are bound together by a zone decorated with the Greek fret. The _lapis lazuli_ blue has a deeper tint, and is usually decorated with gold. It is used as a ground color, and fine specimens lead one to question the appropriateness of the name, as the porcelain so decorated has a brilliancy and depth far in advance of the comparatively dull stone. The color is occasionally employed in Persian decoration, and varies in shade. [Illustration: Fig. 91.--Chinese Porcelain. Persian Style. (J. C. Runkle Coll.)]