240 DOMAIN III. ARGILLACEOUS. 



With heat it loses its water, and dimi- 

 nishes in bulk ; but a very violent heat 

 converts it into a white amel. When com- 

 bined with lime it easily enters into fusion. 



Argil, also called Alumina by recent 

 chemists, is of great utility, as forming the 

 basis of many manufactures, such as brick, 

 porcelain, and earthenware. It constitutes 

 98 parts in the 100 of corindon; under 

 which division are now classed the most 

 perfect of the precious stones, after the 

 diamond, such as the sapphire, ruby, and 

 oriental topaz. It is hence not only one 

 of the most noble, but one of the most 

 useful of the earths ; loam or fertile soil 

 being a mixture of about 30 parts argil 

 with 70 of fine sand ; while mould chiefly 

 consists of animal and vegetable remains. 



In the primitive rocks argil is an im- 

 portant feature, forming about a fifth part 

 of felspar, and a third of mica. The most 

 ancient slates abound in argil. It is often 

 so homogeneous that it cannot be regarded 

 as the waste of former mountains, but a 

 pure deposit of primeval waters. In the 



