80 CARBON THE BASIS OF FOSSIL COAL. 



ancient vegetation, termed fossil coal ; and which, 

 perhaps, exceed in quantity a hundred fold, all 

 the trees and plants that now cover the surface of 

 our planet. 



Still greater is the quantity of carbon which is 

 locked up in a latent state of combination with 

 lime and other rocks ; for it constitutes about i 

 of the widely diffused strata of carbonate of lime, 

 which forms the basis of extensive territories in 

 every quarter of the world. Although it is now 

 fully established, that all the varieties of fossil 

 coal are of vegetable origin, geologists seem not 

 to have ascertained, or even inquired, why the 

 chemical constitution of coal is so various in dif- 

 ferent regions. In Wales, and in several moun- 

 tainous portions of the United States, there are 

 extensive deposits of hard coal, termed anthra- 

 cite, consisting almost entirely of carbon, which 

 burns slowly, and without flame ; while all the 

 other varieties of fossil coal are composed of car- 

 bon, united with various proportions of hydrogen, 

 oxygen, and in some cases of nitrogen, with the 

 exception of Cannel coal, which is without oxy- 

 gen. The following facts may tend to throw some 

 light on this obscure subject. 



1 . So far as the knowledge of the writer ex- 

 tends, anthracite is confined to regions that have 

 been elevated by subterranean fire, and at Car- 

 bondale in Pensylvania presents every appear- 

 ance of having undergone the action of intense 

 heat. 



