Chap. IT. A Trextifcof BODIES. lop 



hcavic as a folidcone. For we may anfwcr, that feeing the a- 

 tomcs muft ftrikc through the body; and that a eefliblc body 

 doth not receive their ftrckes fb firmly as a ftiffe one; nor can 

 convey them fo far re : if unto a ftiffe fuperficies there fuccecd a 

 yielding infide- the ftrokcs muft of necefTity lo.'e much of their 

 force; and confcquently.cannot move a body full ofairc with fb 

 much celerity, or with fb much efficacy as they may a fblid one. 



But then you may peradventure fay, that ifthcfe flrokcs of 2 . 

 the defending atomes upon a denfc body, were the caufe of its The fcconJob- 

 motion downwards, we muft allow the atomes to move farter j a 

 then the denfr body; that fb they may flill overtake it and drive ^ 

 it along, and enter into it: whereas if they fhould move flower ' 

 then itjiione of them could come in their turn to give it a ftroke, " e k n e .^ * c 

 but it would be paft them, and out of their reach before they body.'" 8 

 :ould ftrikc ir. But it is evident (fay you)out of the.'c pretended 

 :aufcs of this motiou, that fuch atonies cannot move fb fwiftly 

 lownwarc's, as a great denfc bodie; fined their littlenefTe and 

 jieir rarity , are both of them hindering to their motion : and 

 jiercfore this cannot be the caufe of that cfFefr, which we call 

 gravity. 

 To this I reply ; That to have the atomes give thefe blows 



a defcending denfe body, doth not require that their naturajl 

 ind ordinary motion fhould be fwiftcr then thede/cent of fucli 



1 denfc body: but the very deferent of it occafionerh their ftriking 

 L; for as it falleth and maketh it felf a way through them, they 

 lividethemfelvcs before it, an3 fwell on the fides and a lirde 

 ibove it, and prefently clo'e agiin behind it and over it affoon 

 is it is paft. Now that clofing to hinder vacuity of fpace is a 

 udden one, and thereby attaineth great velocity; *,vhieh would 

 :arry the atomes in that degree of velocity further then the de- 

 cending body, if they did not encounter with it in their way to 

 etard them : whichencounter and retarding irnplycth fjcii 

 irokcs upon the denfe body as we fuppofc to caufe this motion. 

 \ndthe like we fee in water, into which letting a ftone fall, 

 >refently the water that was divided by the ftone, and fwejieth 

 >n the fides higher then i: was before, clolcth upon the back of 

 he defending ftone, and followeth it fo violently, that for a 

 vhi!e after it leaveth a purling hole in thephce where the fton^ 

 vent down, till by the repo r eof the ftone, the water rctatnei'i 

 ikcwifc to its quiet; and lo its fuperficies becometh even. la. 



