DOMAIN VI. CARBONACEOUS. 



deserve to form a variety in the systems of mine- 

 rals, if it did not pass by imperceptible degrees 

 to the varieties which precede it, and to that 

 which follows. Its history, in strict language, 

 more properly belonging to geology, than to 

 mineralogy. 



" Earthy lignite*. This substance is black, 

 or of a blackish brown, mingled with a reddish 

 cast. Its fracture and aspect earthy, fine grain- 

 ed, rather soft, even friable, smooth to the feel, 

 and becomes bright by scraping. It is nearly 

 as light as water. It burns, emitting a disa- 

 greeable smell. 



<c It not only often contains remains of vege- 

 tables, but sometimes itself presents the texture 

 of wood, without ever possessing either the co- 

 lour or brightness, or the hardness of the pre- 

 ceding varieties. 



" Earthy lignite, burns sufficiently free to be 

 used as fuel ; it gives a gentle and equal heat, 

 but exhales an odour generally unpleasant, but 

 sometimes rather agreeable. 



" It is found sometimes in the midst of secon- 



' * Biluminose hoherde, earthy bituminous wood. Broch. 

 Vulgarly earth of Cologne, and sometimes, but improperly Umler. 

 Umber, properly so called, which comes from Italy, or the East, 

 containing nothing that is combustible, cannot belong to this spe- 

 cies," 



