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fermentation, 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 were, 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 off 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 attempted to be explained ; since, in all 

 bituminous substances, the abundant existence of these three prin- 

 ciples 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 



