82 NATURAL HISTORY 
bears to the circumference of the globe, and it will Hill be more 
diminifhed, in proportion as the lurtace of round bodies, is larger 
than the diameter. Confider then, (if we may compare fmall things 
to great ) that if a potter were to make a globe of clay, and 
fmooth it whilfl it was moift, with all imaginable care, then fet it 
afide to dry, is it poffible that the foft fhould become hard, that 
the hard fhould become equally compact, and the texture exactly 
uniform, without luch rifings and fallings, fuch eminencies and 
depreflions, as we may now fee on the globe ? Would there be no 
parts which would project ~ part farther than the reft ? I conclude 
therefore, that the earth’s indurating into a Superficies, uneven in 
the fame degree as our prefent globe, was the natural refult of a 
mafs of heterogeneous matter, unequally difperfed, palling from a 
ftate of liquidity, into a ftate of folidity and hardnefs. To return, 
sect. vi. Sand is of various ufe, and according as it is differently con- 
Ufes Of lands, j mea n, frefh or fait, of a cryftal or fpar bafts, fmooth, 
or rough and angular, tranfparent or opaque, pure or mixed, it is 
chofen by artifts for cafting metals, making glafs, cutting and polifh- 
ing marble and free-ftone, fixing of cement, and the like; but it 
is chiefly ufeful in Cornwall (according to the common opinion) in 
matters of hufbandry, and therefore collected at a great expence 
from the neareft fea-coaft, although indeed it is, generally fpeaking, 
not the fand, but the mixtures we find with the fand, which fer- 
tilize the land upon which they are carried. For fand being only 
a congeries of pebbles, or little grains of ftone, can do little more 
than keep the ground loofe and brittle, and this will go but a little 
way towards giving the hufbandman a good crop ; it is to the mix- 
ture of fait, flime, fhells and coral, that we owe fertility. 
Sea-fand. Sea-fand has greatly the advantage of river-land in agriculture, 
and the falter the better, but all fand that is wafhed by the fea, 
is not equally proper for manure. In Mount’s-bay, on the 
beach between Penzance and the Mount, we obierve that when 
the North wind blows, and the water is fmooth, we meet 
with a fine, light, opening fand, good for corn and grafs; for 
the fea then moving gently, and equably, whilft the North wind 
blows from the Ihore, drives the lighted: fand foremoft, into a 
truck, courfe, or chanel by itfelf, and gives leave to the more 
impure, and gravelly parts of thole lands, to fettle feparately and 
farther back ; but when the wind blows from the South, and the 
fea is turbulent, it confounds find and gravel together, making 
a mixture utterly unfit for hufbandry. In other filiations the 
wind that blows off land muft for the lame reafon, difpole the fea 
to leave behind it the beft fand. 
Blown 
