44 AviS INERTIAE

ties, or masses of matter, how unequal soever,

with

xnedium were in any part: and there being less resist-ance towards the side where it was rarer, they wouldrecede to that side, till their forces were in equilibria ,and the whole mast of this medium became of an equaldensity. In which cafe, their elasticities balancing eachother, the particles would rest, and produce no effectupon any dense body either without or within its surface.This is the very cafe of our air, whose elastic, repell-ing particles could never, I think, be supposed the causeof bodies being impelled to each other in it.

Farther, let me anticipate, in some measure, here,an argument I shall insist upon below. The action ofthis fluid is supposed the cause why the parts of thesegreat bodies, the fun, planets, comets, gravitate to thebodies themselves (fee the Question cited) that is, gra-vitate towards one another; or it is supposed to actwithin the folidity'of these bodies. Now there is suchan affinity between the mutual attraction of the internalparts of great bodies (as the earth) and the internalparts of small bodies (as a stone, gold, £5V.) while theylie in the strata : that is, between the attraction of gra-vitation and the attraction of cohesion, that if it is ab-surd to offer a mechanical solution of the one, it seemsno lest absurd to offer to solve the other mechanically.Why might we not suppose that the action of this fluidimpels the internal parts of marble to one another, asit doth the internal parts of the earth ? Is there a dif-ferent cause of cohesion, when the marble lies in thestratum in the bowels of the earth, and when it isbrought up to the surface ? All the arguments that

ever