io6 Josiah Wedgwood CHAP. 



shire, and Cornwall. It was mixed with a due propor- 

 tion of ground flint. The pieces were fired twice, and 

 the glaze was applied after the first firing, in the same 

 manner as on porcelain. The glaze was a vitreous 

 composition of flint and other white earthy bodies, with 

 an addition of white lead for the flux analogous to 

 common flint glass; so that, when prepared in per- 

 fection, the ware might be considered as coated over 

 with real flint glass. 



The entirely new pieces of earthenware and porcelain 

 which Wedgwood produced, as the result of his chemical 

 investigations, were the following : 



1. A Terra-Cotta, resembling porphyry, Egyptian 

 pebble, and other beautiful stones of the silicious or 

 crystalline order. 



2. Basaltcs or Egyptian, a black porcelain biscuit of 

 nearly the same properties with the natural stone. It 

 bears without injury a strong fire, stronger indeed than 

 the basalt itself. 



3. White Porcelain Biscuit, of a smooth, wax-like 

 surface, of the same properties as the preceding, except 

 in what depends upon colour. 



4. Jasper, a white porcelain biscuit, of exquisite 

 beauty and delicacy, possessing the general properties 

 of the preceding, together with the singular one of 

 receiving through the whole substance, from the admix- 

 ture of metallic calces with the other ingredients, the 

 same colours which those calces communicate to glasses 

 or enamels in fusion, a property which no other porce- 



