H 



130 Mr, HatchettV Ohfcrvatlons on Bituminous Subjlances* 



Jet, 



Pit Coal, 



Bituminous Wood, 

 Turf, 

 Peat, and 

 tkofe combinations of the oxides of certain metals with bitumciv 

 called Bituminous Ores*. 



Thofe who are acquainted with the nature of thefe fubftances 

 will immediately perceive, that they may be formed into two divi- 

 fions : the firfi: of which confifts of fimple fpecies, or unadulterated 

 bitumens: and the fecond is compofed of bitumen mixed or com- 

 bined with the earths, vegetable matter, and metallic oxides; fo that 

 thefe appear to merit the name of compound fpecies. 



I (hall now firft confider how the fimple fpecies are connected 

 with each other. 



§ 2. 



IT has been the opinion of fome eminent Naturalifts and Chemifts, 

 that naptha is an ethereal oil produced from the more compact 

 and folid bitumens by a fort of natural diftillation. This however 

 appears to be an hypothefis founded upon analogy, and fupported 

 only by a few local facts which may often be queftioncd. But 

 many facts and obfervations concur to prove that the contrary mod: 

 frequently happens, and that the. compact bitumens are often, if 

 not always, formed from naptha and petroleum by infpifTation. 

 I will not however now infift upon the proofs of this, as the varie- 



* As I intend only here to notice the modifications of naptha and petroleum, I have 

 not mentioned amber and the honey-ftone, 



ties 



