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The process by which this substance is formed I shall take the 
liberty to consider as of the fermentative kind, and shall distinguish 
it by the name of bituminous fermentation ; defining it— ^ fer- 
mentation peculiar to vegetable matter placed in such situations, as 
not only exclude the external air, and secure the presence of moisture, 
but prevent the escape of the more volatile principles; and which 
terminates in the formation of those substances termed bitumens. 
Having here distinguished this process, for the first time, as a 
species of fermentation, its right to such a distinction ought to be 
ascertained as soon as possible ; but as the circumstances on which 
its claim depends are to be found in the history of the phenomena it 
produces, and of the results of its operation, we will first hasten to 
their consideration. 
In a process carried on in the recesses of the earth, or, at least, 
in situations from which our observations are excluded, it is not to 
be expected, that a complete history of all the phenomena which 
occur during the whole of the operation can be possibly made out. 
To furnish a satisfactory account, we must have recourse to infe- 
rence and analogy : thus aided, we may, I trust, with only the pro- 
duct of the operation before us, be enabled to form well-founded 
conjectures on the phenomena which have actually taken place. 
Almost all vegetable matters manifest a strong disposition to de- 
composition, when the separation of their integrant molecules is 
aided by the interposition of the particles of water ; and particularly 
if, with this, is combined the powerful energy of caloric. ^ If this 
latter agent be employed, only in a low degree, an intestine mo- 
tion among the integrant molecules takes place, the equilibrium 
by which that particular mode of composition was preserved is 
broken, a separation of the constituent principles takes place, they 
become influenced by new attractions, and then enter into new 
combinations and modes of existence. By this process, the fer 
mentative process, a resolution of the original compound, is effected. 
