10 WISCONSIN ACADEMY SCIENCES, ARTS, AND LETTERS. 



examined the places from whicli they take the material. * * =<' 

 I have to record the unexpected fact that the material froin which 

 the porcelain of King-te-chin is made, is taken from certain strata 

 intercalated between these slates, and occurring at several places, 

 separated^from each other laterally, i. e., at right angles] with the 

 strike of the rocks. It is a rock of the hardness of felspar (inferior 

 kinds are not so hard) and of a green color, which gives it to some 

 extent, the appearence of jade to which the Chinese too, compare 

 it. The rock is reduced b}^ stamping to a white powder, of which 

 the finest portion is ingenious!}'- and repeatedly separated. This is 

 then moulded into small bricks. The Chinese distinguish chiefly 

 two kinds of this material. Either of them is sokl in King-te-chiii 

 in the shape of bricks, and as either is a white earth, they offer no 

 visible differences. They are made in different places by pounding 

 hard rock, but the aspect of the rock is alike in both cases. For 

 one of these two kinds of material, the place " Kaoling " was in an- 

 cient times in high repute, * * * * ^^-^^ w-^q Chinese still 

 designate by the name " kaoling" the kind of earth which was for- 

 merly derived from there. * * * ""' The second kind of 

 material bears the name pe-tun-tse, (" white claj-.'") S. W Will- 

 iams, in his " Middle Kingdom," speaks* of the kaolin as a dis- 

 integrated granite, which is almost all felspar — and of the '' pe- 

 tun-tse ''as nearly pure quartz — but his account does not appear to 

 be based on personal inspection. 



One of the most famous kaolin localities of Europe is that at St. 

 Yrieix-la-perche, near Limoges, in France. Here is obtained the 

 material for the famous Sevres porcelain manufactory .f The kaolin 

 occurs as a result of the disintegration of masses of pegmatite 

 partly interstratified with the gneiss and partly intersecting it in 

 cross veins. The gneiss is also decomposed, but to a red clayey 

 mass of no value. The pegmatite, consisting chiefly of felspar, 

 wherever decomposed has given rise to an excellent kaolin, moder- 

 ately free from quartz and rocky particles, these forming only 

 about ten per cent, of the whole. 



Another famous European occurrence of kaolin is that of the 

 vicinity of St. Austle in Cornwall. This is a weathered mixture oi 

 orthoclase and quartz, chiefly on Tregoning hill near Helstone,t in 



-:=-Vo]. II, pp. 116, 117. 



t Dana's Mineralogy, p. 475; Krapp's "Chemis'y Applied to Arts," vol. ii, p. 230. 



X Wagner's Chem. Technol. Eng. Ed. 



