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shall be enabled, especially by recollecting what has been just said of 
the other species of fermentation, to determine whether it is right to 
admit of the existence of such a species of fermentation or not. 
Secured on every side by the surrounding earth, the mass of 
vegetable matter is preserved, as it w^ere, in a well-closed vessel ; 
hardly any escape being permitted to its more volatile particles ; 
nor any admission of extraneous matters allowed, except of such 
as are introduced with the water, which insinuates itself by soaking 
through the interstices of the earthy particles, composing the several 
strata which inclose it. This mass of vegetable matter, now deprived 
of the energy of vegetable life, must undergo some change; but, 
from the closeness of its preservation, it cannot admit that escape of 
the gaseous matters on which the commencement of the vinous, ace- 
tous, or putrid fermentation depends : another process is therefore 
instituted. The hydrogen, carbon, and oxygen are disengaged from 
their former attachments, but, being prevented from flying oiF in a 
gaseous state, are obliged again to unite, and to enter into new com- 
binations. Under these particular circumstances, a substance may 
be expected to be formed containing a considerable portion of these 
principles so abundant in vegetable matter. In this respect, there 
undoubtedly may be discovered a remarkable agreement between 
the supposed product of this fermentation, and the assumed process 
by which its formation is here attempted to be explained ; since, in 
all bituminous substances, the abundant existence of these three 
principles has been sufficiently proved by analysis. 
In this, as in every other species of fermentation, a considerable 
difference may exist, as to the degree of perfection to which the 
process may proceed, and, of course, as to the degree of perfection 
which the product may possess. Thus I expect to shew, that, ac- 
cording to length of time, exclusion from the air, and the existence 
of other favourable circumstances, will these bituminous substances 
