PORCELAIN MANUFACTURE. 121 



of the same granite rocks, being simply felspar in a less 

 advanced state of decay ; and at Belleek, Fermanagh, 

 kaolin is obtained from the undecomposed red granite of 

 the district, which becomes white when calcined, the iron 

 being extracted by magnets. 



The Chinese began the manufacture of porcelain some 

 two thousand or more years ago, and at the present day 

 have large manufactories, King-ti-chin alone boasting, it 

 is said, nearly 3,000 kilns. Chinese porcelain was first 

 introduced into Europe in the sixteenth century, but no 

 real progress was made in imitating it until the eighteenth 

 century, when Bottcher, of Dresden, made first a red ware, 

 and then white porcelain. 



Earthenware of a coarse kind was manufactured in 

 Staffordshire from a very early period. 



In one of the ranges of the Appalachian mountains, 

 known as Blue Ridge, the rocks (which are principally 

 gneiss) are decomposed to a depth of fifty feet or more, 

 and converted into a reddish, greasy, brick-clay ; for gneiss 

 is composed of the same three minerals as granite, but these 

 are arranged in plates instead of grains, and in the Blue 

 Ridge rocks the plates of quartz may be seen in their 

 original positions, embedded in clay. In some of these 

 rocks the various stages of decomposition may be well 

 observed. Thus the upper part is completely kaolinised, 

 and almost entirely freed from the iron which gives the red 

 tint to the coarser clay; lower down the rock is partly 

 decomposed, and lower still quite unchanged, so that 

 it seems evidently to have been decayed from without, 

 probably by water charged with carbonic acid filtering 



