The reigns of Yung Chêng and Ch’ien Lung were prolific in monochromes. Never since the Sung dynasty had these wares been produced in such quantity, and the tale of the glazes was swollen to an unprecedented extent by the accumulated traditions of the past centuries, and by the inventive genius of T’ang Ying. It is scarcely practicable to attempt to distinguish very closely between the Yung Chêng monochromes and those of the early years of Ch’ien Lung. The activities of T’ang-ying extended from 1728–1749, and we are expressly told that many of the types enumerated in the Imperial list were his inventions, besides which there was nothing made by the potters of the past which he could not reproduce. To enumerate all the colours now used would be merely to repeat what has been said under the heading of monochrome porcelain in the previous chapters. Moreover, the Imperial list given on page 223 serves to draw attention to the principal types, and it is only necessary here to supplement it with a few comments. A special feature of the time was the reproduction of the glazes made in the classical periods of the Sung and Ming dynasties, and in many cases these copies were based on originals lent to the factory from the Imperial collections. Thus the Ju, Kuan, Ko, Lung-chüan, Tung-ch’ing, Chün and Ting wares, all the specialities of the Sung dynasty, are included in the list, and though one type of Kuan glaze is specifically stated to have been laid on a white porcelain body, many of the others, we read, were provided with special bodies imitating the copper-and iron-coloured wares of antiquity. But experience shows that in the majority of cases the potters were content to simulate the “brown mouth and iron foot” of the dark-bodied Sung wares by dressing the mouth and the exposed part of the base with ferruginous clay. This is observable on the lavender crackles which imitate the Kuan, and the stone grey crackles of the Ko type, by which the Sung originals were until recent years represented in most Western collections. In other cases coarse clays of impure colour, and even earthenware bodies were used in the reproductions. The admirable imitations of the mottled and _flambé_ Chün glazes which were apparently a special triumph of T’ang-ying appear both on a white porcelain which had to be carefully concealed by the coloured glazes, and on a soft earthenware body. Both these kinds are found with the Yung Chêng mark stamped in the paste, and so correct are the glaze effects that even collectors of considerable experience have been deceived by specimens from which the mark in question has been ground away.