In this short reign, which Chinese writers regard as the most brilliant period of their porcelain industry, the number of kilns occupied with the Imperial orders had increased to fifty-eight, the majority of them being outside the Imperial factory and distributed among the private factories. According to the _T’ao lu_,[16] the clay used at this time was red and the ware like cinnabar, a statement which is difficult to reconcile with the glowing description of the jade-like white altar cups and other exquisite objects for which the reign was celebrated. It is, of course, possible that a dark coloured body was employed in some of the wares, as was done at other periods, or it may be that the words are hyperbolically used to describe a porcelain of which the exposed parts of the body assumed a red colour in the firing. This latter peculiarity is noticeable on specimens of later Ming porcelain, particularly the blue and white of the Chia Ching period. But in any case a red biscuit cannot have been invariable or even characteristic of the period, for no mention is made of such a feature in the _Po wu yao lan_, which gives by far the fullest account of the Hsüan Tê porcelain. The description in the _Po wu yao lan_,[17] which seems to have been generally accepted, and certainly was largely borrowed by subsequent Chinese works, may be freely rendered as follows: “Among the wares of the Hsüan Tê period there are stem-cups[18] decorated with red fish. For these they used a powder made of red precious stones from the West to paint the fish forms, and from the body there rose up in relief in the firing the precious brilliance of the fresh red ravishing the eye. The brown and blackish colours which resulted from imperfect firing of the red are inferior. There were also blue decorated wares, such as stem-cups with dragon pine and plum designs, wine stem-cups with figure subjects[19] and lotus designs, small cinnabar pots and large bowls in colour red like the sun, but with white mouth rim, pickle pots and small pots with basket covers and handles in the form of bamboo joints, all of which things were unknown in ancient times. Again, there were beautiful objects of a useful kind, all small and cleverly made with finely and accurately drawn designs. The incense vases, trays and dishes[20] were made in large numbers, and belong to a common class. The flat-sided jars with basket covers, and the ornamented round pots with flanged[21] mouth for preserving honey, are very beautiful and mostly decorated in colours (_wu ts’ai_). The white cups, which have the character _t’an_ (altar) engraved inside the bowl, are what are known as 'altar cups.’ The material of these things is refined and the ware thick, and the form beautiful enough to be used as elegant vases in the true scholar’s room. There are besides white cups for tea with rounded body,[22] convex[23] base, thread-like foot, bright and lustrous like jade, and with very finely engraved[24] dragon