the mean Denfity of the Earth. 7 8 1 
that of 1780410 9933, or 1434 to 800 nearly, or almoft 
as 9 to 5 . And fo much does the mean denfity of the 
earth exceed that of the hill. 
Thus then we have at length obtained the objecft 
which we have been in queft of through the very labo- 
rious calculations that have been defcribed in this paper, 
and in the furvey and meafurements from which thefe 
computations were made ; namely, the ratio of the mean 
deniity of all the matter in the earth, in comparifon with 
the denfity of the matter of which the hill is compofed. 
And that ratio we have found to be equal to the ratio of 
9 to 5. And, for the',reafons before mentioned, I think 
we may reft fatisfied, that this proportion is obtained to a 
confiderable degree of proximity, probably to within the 
fiftieth part, if not the hundredth part of its true mag- 
nitude. Another queftion, however, ftill arifes, namely, 
what is the denfity of the matter in the hill? Is its mean 
denfity equal to that of water, of fand, of clay, of chalk, 
of ftone, or of fome of the metals? For, according to 
the matter, or different forts of matter, of which it is 
formed, and according as it is conftituted with or with- 
out large vacuities, its mean denfity may be greater or 
lefs, and that in a degree which is not certainly known. 
A confiderable degree of accuracy in this point could 
only be obtained by a clofe examination of the internal 
ftrudture 
