In the case of the pale opaque blue (to which the name of turquoise may be applied more aptly than to the sky-coloured transparent blues of the _demi grand feu_), the surface of the enamel is sometimes painted with an irregular net-work of black lines, as if in imitation of some kind of marble. This turquoise enamel towards the end of Kien-lung’s reign was often applied to the surface of large vases, and when in combination with a lemon-yellow decoration the effect is even more unpleasant than when used alone. We have mentioned, when speaking of Yung-cheng’s reign, a valuable list of the various kinds of porcelain made at that time at King-te-chen. We must now refer to another document, quoted, like the list of Nien’s time, in all the Chinese books dealing with the history of the imperial porcelain works. The emperor Kien-lung, it would appear, when overhauling certain manuscripts preserved in the palace, came upon a series of twenty water-colour drawings illustrating the manufacture of porcelain. He at once summoned Tang-ying, the famous superintendent at King-te-chen, to Pekin, and, handing over the drawings, commanded him to prepare a full description of all the processes illustrated in these pictures. This was in 1743, shortly before Tang’s retirement. The drawings themselves have never been made public; but we have in Tang’s report what is, after the letters of the Jesuit father, our most important source for the technical details of the manufacture of porcelain in China. With these details we are not concerned just now, but we will quote from Dr. Bushell’s translation a disquisition on certain principles that should govern the forms and decoration of porcelain. This is a kind of _obiter dictum_ of Tang-ying, _à propos_ of the fashioning and painting of vases. In his flowery style he tells us (I abbreviate in a few places): ‘In the decoration of porcelain correct canons of art should be followed. The designs should be taken from the patterns of old brocades and embroidery; the colours from a garden as seen in spring-time from a pavilion. There is an abundance of specimens of ware of the Sung dynasty at hand to be copied; the elements of nature supply an inexhaustible fund of materials for new combinations of supernatural beauty. Natural objects are modelled to be fashioned in moulds and painted in appropriate colours. _The materials of the potter’s art are derived from forests and streams, and ornamental themes are supplied by the same natural sources._‘[68] It is a strange fancy which connects the decoration of a vase with the source of the materials with which it is made. Elsewhere, speaking of the painting of the blue and white ware, Tang-ying says: ‘For painting of flowers and of birds, fishes and water-plants, and living objects generally, the study of nature is the first requisite. In the imitation of Ming porcelain and of ancient pieces, the sight of many specimens brings skill.’ We see in