194 



ILLUSTR/SiTlONS OF THE 



Note ix. § 31 



Petroleum, i^c. 



7 



According to the theory of coal laid 



do 



above, its two chief 



charcoal 



and bitumen, being furniihed by the vegetable 

 and animal kingdoms, both of the land and of 

 the 



fea, have formed with one another 



comb 

 heat : 



by the adlion of fubterraneous 



b 



have alfo. in fome 



afes, been fep 



rated by that fame adlion, where the degree of 

 compreffion neceflary for their union, happened 



be wanting 



The carbonic part, when thus 

 feparated from the bituminous, forms an infufi- 

 ble coal, which burns without flame : the bitu- 

 minous part, when feparated from the carbonic, 

 is found in the various ftates of naphtha, petro- 

 leum, afphaites, and jet. 



The great refem.blance of infulible or blind 



coal, to 



f b 



ide 



e refiduum obtained by the diftilla- 

 iminous coal ; and again, the coin- 

 the bitumens juft named, with the 



volatile part, or the matter brought 



fuch dill 



are 



itrong 



guments in 



by 



fa- 



of this theory. The other fact 



hiflory of coal, ferv 



to 



onfi 



the fame 



concloiion ^ but it muit be confelTed, that what 



we 



