56 DOMAIN HI. ARGILLACEOUS. 



the first being of a finer grain, while the latter 

 seems to graduate into the stone used for sharp- 

 ening scythes, and which, froni the coarser 

 grains of silex, becomes an argillaceous sand- 

 stone. Patrin informs us that hones are found 

 in the mountains of Jura, and the Vosges*; and 

 the substance was found on digging a well an 

 extreme depth, at Hampstead, near London. 

 Chinese Clay slate has seldom been used for orna- 



cameos. 



mental purposes ; but the Chinese, a most intel- 

 ligent and ingenious people, and amounting, by 

 the most moderate computation, to about two 

 hundred and thirty millions of souls, or one- third 

 of the human race, have rivalled the ancients in 

 converting to utility and ornament numerous 

 articles of the mineral kingdom; and, among 

 the rest, this substance has not escaped their 

 attention. 



" The cameo slate of the Chinese is also a 

 primitive argillaceous schistus, of a very fine 

 paste, softer than the hone, and which presents 

 three, or even four, successive layers, very thin, 

 of different colours very- neatly divided, and 

 strongly adhering to each other. 



" The Chinese artists have availed themselves 

 of the disposition of this stone. They form 



\ 



* i. 123. 



