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minute a disintegration, the bituminous particles must have been 
set free ; and must have risen to the surface, with as great a degree 
of rapidity, as the earthy and metallic particles would have sought 
the bottom. But, on the supposition of Mr. Kirwan, the bituminous 
and carbonaceous, the earthy and the metallic, particles, being 
all suspended in the same fluid, a deposition of the carbon and 
bitumen must have first taken place, and this have been succeeded 
by the descent of the earthy, and of the still more ponderous metallic 
particles. 
It appears equally difficult to conceive the formation of beds of 
shale, by the subsidence of bitumen. If, says IVIr. Kirwan, the 
petrol were in the greatest proportion, it frequently sunk first, in the 
form of a soft bitumen, carrying with it the clay, and forming beds of 
shale, or bituminous shale, according to its proportion. Considering 
this position, with all that care and deference, which a dissent from 
the opinions of so justly celebrated a chemist ought to excite, I still 
am unable to discover, how the effects here described could possibly 
result from such a combination of circumstances as those to which 
they are thus ascribed. 
Mr. Hatchett, whose most valuable observations on the bitumens 
have very much facilitated our inquiries into the nature and origin 
of these substances, is very decidedly of opinion that coal, as well 
as the other bitumens, are of vegetable origin ; although he does not 
deny the possible intermixture of animal matters. But we shall 
soon have occasion to advert more fully to these observations, to 
which the science of chemistry is so much indebted. 
Mons. Patrin states, that volcanos throw up large quantities of 
bituminous and argillaceous matters ; and he derives the origin of 
coal from this source : supposing that coal, and its interposed beds 
of stone, have been deposited by the alternate ejection of bitumen, 
and of earthy matters, from submarine volcanos. How, he says. 
