

Chip. n. * TifAtificf BODIES. 



fink into our body without our perceiving any fenfiblc caufc of 

 them:for no quettion but thefe atomes are the immediate caufes 

 ofall good and bad qualities in cheairc. Laflly, when we confi- 

 der that we cannot long together hold out our arm atlength,or 

 our foot from the ground, and reflect upon fuch like impoten- 

 cies of our rcfifting the gravity of our own body : we cannot 

 doubt buc that in thcfe cafes we feel the effect of thefe atomes, 

 working upon thofe parts ; although vve cannot by our fcnie 

 difcern immediately that thefe are the caufes ofit. 



But now it is time to draw our Reader out of a difficulty, j . 

 vvhich may peradventurc have perplexed him in the gieateft part HOW in the 

 of what he hath hitherto gone over. In our inveftigation of the 2ty C miy 7 '! 

 Elements, we took for a principle thereunto : that gravity is g-ter then 

 fometimes more, fbmetimes lefle, then the denficy of the body in denfity' then 

 \vhichit is. But in our explication of rarity and denfity : and ffnmthe 



. . .. f r rl *cv b the 



again in our explication of gravity; we !ecm to put, that gravity fame thing, 

 and denfity is all one. This thorn I apprehend , may in all this 

 diftance, have put fome to pain : but it was impoflible for me to 

 remedy it; bccaufel had not yet delivered the manner of gravi- 

 tation. Here then I will do my bcft, to aflwage their grief, by 

 reconciling thefe appearing repugnancies. 



We are therefore to confider,that denfity (in it felf)doth figniffe 

 a difficulty to have the parts of its fubjecSt, in w ch it is, fepa rated 

 one from another; and that gravity (likcwife in it felf) doth fig- 

 nific a quality, by which a heavy body doth defcend towards the 

 center; or fwhich is confequent thereunto,) a force to make an- 

 other body dc/ccnd.Now this power,we have (hewed, doth be- 

 long unto denfity/o far forth as a denfe body being ftrucken by 

 another, doth not yield by fuffering its parts to be divided; but, 

 with its whole bulk ftriketh the next before it,and divideth it, if 

 it be more divifiblethcn it felf is.So that you fee,dcnfity hath the 

 name o&Jenfity> in consideration of a paflive cuality or rather 

 of an impaffibility which it hath; and the fame denfity is called 

 gravity, in refpecl of an active quality it hath which followcth 

 this impaffibility. And both of them are eftimated by the diffe- 

 rent refpec^s which the fame body or fubjecl:, in which they are, 

 have unto different bodies that arc the terms whereunto it is 

 compared; for the active quality or gravity ofa denfe body, is e- 

 ftecmed by its refpe6l to the body it ftriketh upon ; \\hercas its 



H 4 den- 



