We can now return to Ho Ch'ou, who "took green ware and made _liu-li_."[306] It has been thought that what he made must have been a kind of porcelain, but there is no indication of any such achievement, for though it is possible to make an artificial porcelain with glass as a constituent, the converse is not true: you cannot make glass out of either pottery or porcelain. The most probable explanation of the passage seems to be that Ho Ch´ou (who was apparently not a potter) experimented at some pottery with the materials used in glazing the green ware, and found that he could make a very good glass (_liu-li_) with the potter's green glaze, and perhaps other ingredients, a result which is in no way surprising, seeing that the softer ceramic glazes have a very close affinity to glass. But no further inferences can be drawn from this passage, and it is not even clear that Ho Ch´ou made a ceramic ware at all. All we are told is that he made _liu-li_. I have rather laboured this negative point, because Professor Zimmermann has published a declaration of belief that Ho Ch´ou was the discoverer of porcelain.[307] Apart from the obvious criticism which the writer himself anticipates, that such an epoch-making discovery would hardly have escaped the notice of Ho Ch´ou's biographer, Professor Zimmermann opens his case with a fundamental error, for which he has to thank Dr. Bushell. It is true that he only names Julien as the source of his information, but his version of the story of Ho Ch´ou is taken verbatim from Bushell's _Oriental Ceramic Art_,[308] where the crucial passage is unfortunately rendered "but he (Ho Ch´ou) succeeded in making vessels of green porcelain which could not be distinguished from true glass." This mistranslation puts an entirely different complexion on the passage, and goes a long way to justify Professor Zimmermann's inferences that Ch´ou made a glassy ware of the nature of porcelain. It is an instructive instance of the pitfalls which beset the student of Chinese subjects, especially when he has to rely on other people's translations.