Page:Brinkley - China - Volume 1.djvu/312

 CHINA a mystery. Undoubtedly the production of a fine

red was always regarded as a keramic four de force in China. In the Tao-/u it is stated that few potters were capable of producing the C/z-hung vases, and that their manufacture was only attempted by artists ‘who imitated the choice old Kuan-yao (céladon) — that is to say, by specialists. "The eminent chemist M. Salvetat, referring to the Tao-/u’s statement, says: — ‘This is confirmed by what we know of the diffi- culties experienced in maintaining oxide of copper (in the form of silicate of protoxide) at a high tem- perature in the presence of an abundance of atmo- spheric air.” Indeed, it is probable that the best Chinese experts could never cope absolutely with these difficulties, and that infinitesimal variations in the condition of the kiln made themselves apparent in the tone of the glaze. When M. d’Entrecolles investigated the subject of porcelain making at Ching-té-chén, he took pains to acquaint himself with the methods pursued by the manufacturers of Chi-hung monochromes. How far he succceded will be apparent from his account of the matter : —“ Red oxide of copper and the powder of a certain reddish stone were mixed. A Chinese doctor tells me that the stone is a species of alum which is used for medicinal purposes. These are ground in a mortar, the urine of a youth and petrosilex being added to them at the same time. I have not been able to discover the quantity of these ingredients, those who have the secret being careful not to divulge it. The compound is applied to the paste before stoving ; no other glazing matter is employed. I am assured that when this colour is to be given to porcelain no petun- tse is used in forming the péze, but in its place there 282