257 



likely to promote such chemical changes, in the strata of vegetable 

 matter, as would effect its conversion into coal ? This we will there- 

 fore now inquire into. 



That vegetable substances placed in a mass, in a subterranean 

 situation, will, with the aid of moisture, and perhaps, with only that 

 which they themselves contain, pass into a peculiar fermentation, 

 and become thereby converted into bitumen, has been already 

 asserted. Your attention must here, however, be requested to one 

 additional consideration ; which will serve, very probably, to sup- 

 port the application of that hypothesis to the present subject, the 

 origin of coal. 



In the promulgation of that hypothesis you perceived, that the 

 circumstance, on which the bituminizating process was supposed 

 essentially to depend, was the seclusion of the vegetable matter 

 from the atmospheric air. According to the accuracy with which 

 this part of the process was performed, it necessarily follows, would 

 be the approach to a state of perfection, in the product of the ope- 

 ration. Now, by a slight revision of what has been said, in the 

 Letter immediately preceding this, you will not fail to perceive, 

 that whilst endeavouring to ascertain the most probable mode, in 

 which the vegetable matter of the antediluvian world was disposed, 

 there appears great reason to suppose, that the disposition of it 

 must have been such, as would most certainly secure the comple- 

 tion of the assumed process. 



Buried in a considerable mass, thoroughly imbued with water* 

 and covered over with dense, compact strata of earth, its seclusion 

 from the atmospheric air must have been very accurate ; and tak- 

 ing it for granted, that the change it was to undergo would de- 

 pend on these circumstances, then we have every right to conclude, 

 that its conversion into bitumen would be produced most certainly 

 and effectually. 



VOL. I. L L 



