OF CORNWALL. 8 1 
or the folids fettling and indurating in greater quantities in one 
place than in another; a difparity, not the effect of chance, 
nor the accidental concourfe of matter and motion, but pre- 
ordained by God, as productive of more benefit to mankind, 
by the great ufefulnefs of mountains and valleys, than if matter had 
been difpofed in a more exadt and equal manner. 
What will add ftrength to this theory is, that we find the karn 
or foiid rock by no means level, or equi-diftant from the the center, 
but of a wavy furface, riling and falling as the hills and vallies, 
intimating plainly, that as fome parts of the furface of the globe 
fettled done upon ftone, and one rocky ftratum upon another, and 
thereby maintained their elevation and prominency, other parts 
confined oi a thinner fcratum, and there deprelfions were formed, 
the furface became lower, and nearer the center of the earth. 
That this fettling of the earth into unavoidable inequalities, and 
thus generating mountains, may appear more natural and compre- 
heniible to every intelligent reader, let us confider in the next place 
the height of mountains. 
All things are great or fmall by comparifon, and as the mount- sect. v. 
ains are but a part, and a very fmall part too of our globe, and Height of 
we are now enquiring how fuch prominences as we call mountains KimS 
fhould arife, the proper way of eftimating their height, is bv com- in P ro P ortion 
paring them with the diameter and extent of our globe, whofe meter of the 
furface they are thought to deform, and their height and fize carth ' 
reckoned utterly unaccountable. 
Supping then (if we make ufe of round numbers, for which 
we will in the fequel make fufficient allowances) the diameter of 
the earth to be 8000 miles', the higheft mountain will not exceed 
the common furface but one thoufandth part, if it were allowed to 
be eight miles in perpendicular height from the fea ; but the Andes 
of America, reckoned to be the higheft in the world, are not 
judged to be near four miles perpendicular, confequently meafured 
by the diameter of the earth, they are not a two thoufandth part 
higher than the lea. In an artificial globe therefore of one foot 
diameter, the height of the mountains is too fmall to be meafured by 
fcale and compafs, nay it efcapes the fight ; in a globe of eight feet 
diameter thofe uneveneffes which to the eye that fees fo fmall a part 
or the earth at a time are fo ftupendous, are demonftrably not fo great 
as the twentieth part of the decimal of one foot ; in other words in fo 
large a globe, as that of eight feet diameter, the higheft mount- 
tains are not prominent more than the thicknefs of half a crown 
Englifh money. Again, conlider the proportion which this height 
c Calculated to be no more than 7970. 
Y 
bears 
