SELENIUM. VEGETABLE SUBSTANCES. 



it has been scarcely seen. The oxide of cerium 

 (cerite) is found native. There appear to be two 

 oxides, the white and the red. 



SELENIUM. 



Selenium is a metal lately discovered by Berze- 

 lius in the sulphur of Fahhun, in Sweden. Its 

 metallic lustre is considerable, and colour grey. 

 It easily fuses and volatilizes before the blow-pipe, 

 with a smell like horse-raddish. It alloys with the 

 metals. It dissolves in nitric acid, and forms with 

 it a substance which is considered as a new acid, 

 selenic acid, which unites with alkalies, forming se- 

 leniates. 



VEGETABLE SUBSTANCES. 



Animals and vegetables differ essentially from 

 minerals, in the two first possessing life and various 

 organs fit for maintaining it, which is called organic 

 structure. Through these organs, various juices and 

 fluids circulate internally, and thus occasion the 

 growth of the animal or plant. In mineral bo- 

 dies this is not the case ; they increase in size only 

 by successive portions of matter adhering to the 

 outside, nor is there any internal motion. 



The principal ingredients of all vegetables are, 

 oxygen, hydrogen, and carbon : sometimes they 

 contain also a little nitrogen, and other elementary 

 substances; and although these elements are few, 

 yet, by many varieties in their proportions and 

 modes of combinations, a great quantity of proxi- 

 mate constituents are produced. 



