But probably our safest clue to the appearance of Ju ware is to be found in the important passage already mentioned,[105] in which a Sung writer describes the Corean wares as in general appearance like the old _pi-sê_ ware of Yüeh Chou and the _new_ Ju Chou ware. The typical Corean wares of this time are not uncommon, and their glaze--a soft grey green or greenish grey, with a more or less obvious tinge of blue--would satisfy the Chinese phrases, _tan ch´ing_ and _fên ch´ing_, and in the bluer specimens might, by a stretch of poetic phrase, even be likened to the sky after rain. The "egg white," however, must have been a somewhat paler tint if the expression can be taken in any literal sense. From the foregoing considerations we may conclude that the Ju porcelain was a beautiful ware of celadon type, varying in tint from a very pale green to a bluish green. Though it is nowhere definitely stated how long the Ju Chou factories retained their supremacy, it is tolerably clear from Hsü Ching's reference in 1125, or very soon after, to the "modern porcelain of Ju Chou," that they came into prominence towards the end of the Northern Sung period, perhaps in the last half of the eleventh century; and as we have no further information about them, we may perhaps infer that they sank into obscurity when the Sung emperors were driven from the North of China by the invading Tartars in 1127. In any case, the Ju ware seems to have become as extinct as the Ch´ai by the end of the Ming dynasty. Hsiang Yüan-p´ien, late in the sixteenth century, states that "Ju yao vessels are disappearing. The very few which exist are almost all dishes, cups, and the like, and many of these are damaged and imperfect."[106] A few years later another writer[107] declares that the Ch´ai and Ju porcelains had ceased to exist. It is not to be supposed that Ju Chou had the monopoly of the particular kind of _ch´ing_ ware in which its factories excelled. A number of other and not distant potteries were engaged in a similar manufacture, though with less conspicuous success. We read,[108] for instance, that "it was made in the districts of T´ang, Têng, and Yao on the north of the (Yellow) River, though the productions of Ju Chou were the best." It has been already remarked that we possess no authenticated example of Ju porcelain. Doubtless there are many pieces which are tentatively assigned to Ju Chou by hopeful owners. But it must be confessed that the few which have hitherto been published as such are singularly unfortunate choices. Dr. B. Laufer, for instance, in his excellent work on jade,[109] incidentally figures two vases for divining rods of a well-known form, of which he hazards the remark "that both have presumably been made in the kilns of Ju-chou."