4$ '**Tre*tifc of B O D I ES. Chap. j. 



needs alfo give them activity and virtue to pierce the body they 

 a*e beatc againft. 



Now, that celerity is a kind of denfity, will appear by com- 

 paring their natures. For if we confider that a d?nie body may 

 be dilated fo as to poiTefTe and fill the place of a rare body that 

 exceeded it in bignefTe ; and by that dilatation, may be divided 

 into as many and as great parts as the rare body was divifible 

 into; we may conceive that the fubftance of thole parts, was by 

 a fecret power of nature folded up in that little cxtenfion in 

 which it was before. And even fo, if we refleft upon two ri- 

 vers of equall channels and depths, whereof the one goeth fvviC- 

 ter then the other ; and determine a certain length of each 

 channell, and a common meafure of time : we fhall fee that in 

 the fame meafure of time, there palteth a greater bulk of wa- 

 ter in the dcfigned part of the channel of the fwifter ftream, 

 then in the defigned part of the flower, though thofe parts be 

 equall. 



Neither doth it import, that in velocity we take a part of 

 time, whereas in dcnfity it leemcth that an inftant is fufrlcient; 

 and confcquently, there would be no proportion between them. 

 For knowing Philofbphers do all agree that there are noin- 

 ftants in time, and that the apprehcnfion of them proceedeth 

 merely from the manner of our underftanding. And as for parts 

 in time, there cannot be afTumed any fb little, in which thccom- 

 parifon is not true : and fo in this regard, it is abiblutely good. 

 And if the Reader have difficulty at the difparity of the 

 things which are prcfled together in denfity and in celerity; for 

 that in denfity there is onely fubftance, and in celerity there is 

 alfb quantity, crowded up with the fubftance ; he will foon re- 

 ceive fatisfaftion, when he fhall confider that this difparity is 

 to the advantage of what we fay, and maketh the nature of 

 denfity more perfect in celerity, and confequently more power- 

 full in fire then in earth. Befides, if there were no difparity, it 

 g. would not be a diftincl: fpeties of denfity, but the very fame. 

 The fame i$ By what we have fpoken above, it appeareth how fircgetteth 



manner, where- mto fewcll ; now let us confider how it cometh out : for the 

 ^ fire cometh activity ofthat fierce body will not let it lie ftill and relias lone 



ontorfcwell -LI/- . 11 r 



andvorkcth *s it natn lo many enemies round about it to roufe it up. We 

 upon other f cc t h cn t h ac as foon as ,ic hath incorporated it fclf \\ith the 



odics. A ., ., 



fcvvell, 



