Literary references of this kind are open to so many inferences that their value is slight without some tangible specimen to help us to realise their import. This difficulty is greatly increased in dealing with Chinese descriptions because of the ambiguity of Chinese colour words, which is discussed elsewhere. But in the case of Yüeh Chou ware, or at any rate of one kind of it, we have an important clue in another Chinese work. Hsü Ching, who accompanied the Chinese Ambassador to Corea in 1125, in a description of the Corean wares, makes the remark that "the rest of them have a general likeness to the old _pi sê_ ware of Yüeh Chou and the new Ju Chou ware."[69] Fortunately, we can speak with considerable confidence of the Corean wares of this time, many examples of which have been taken from the tombs of the period. The British Museum has a fair number of examples, quite enough to show the typical Corean glaze, a soft grey green celadon of decidedly bluish tint, a thick smooth glaze often of great delicacy and beauty of tone. In view of this the colour of the Yüeh bowls, the blue-green of the hills, is easily visualised. But China boasts so many makes of celadon[70] that he would be a bold man who would single out any one piece and say this is Yüeh ware. Among the numerous specimens of celadon which have reached Europe from various sources it is far from improbable that some were baked in the Yüeh kilns, but at present, alas, we are impotent to identify them. The author of the _Ching-tê Chên t´ao lu_[71] places the Hsing Chou factory at the modern Hsing-t´ai Hsien, a dependency of Shun-tê Fu, in Chihli. Little else is recorded about the white Hsing ware beyond a general statement in the annals of the T´ang dynasty[72] that the "white ware (_tz´ŭ_) cups of Nei Ch´iu were used by rich and poor throughout the empire." Nei Ch´iu, it should be explained, is identified as a township in the Hsing Chou. We may add that the ware of both Yüeh Chou and Hsing Chou was used for "musical cups" by Kuo Tao-yüan.[73] One of the criteria which the Chinese recognise in distinguishing ordinary pottery from the finer wares of a porcellanous nature is the note emitted by the ware when smartly tapped with the finger, and we may fairly infer that any bowls which were suitable for use as musical chimes would be of a sonorous, hard fired material if not actually porcelain.