C hap. 14. A Treat if e of BODIES. 



if a plain fupcrficies fhould befuppofcd to touch another plain 

 one coming perpendicularly to it ; it muft of neceflity be grant- 

 ed to touch it as fbon in the middle as on the fides. Wherefore, 

 if there were any aire (as ofneceffity there mutt be) betwixt the 

 two furfaccs before they touched ; it will follow, that the aire 

 which was in the middle muft have fled quite out from between 

 the two furfaces, as fbon as any part, of the furfaces do touch ; 

 that is, as fboii as the aire which was between the utmoft edges 

 of the furfaccs did fly out; and by confequence it muft have mo- 

 ved in an inftant. 



But if a plain furface be faid to touch a convexc furface ; it 

 touchethitonely by aline, (as Mathematicians demonftratc) or 

 onely by a point. But, to touch by a line or a point, is in truth, 

 not to touch by the form or notion of Quantitie, which requi- 

 reth divifibilitie in all that belonged! unto it ; ) and by confe- 

 quence among bodies it is not to touch j and fo, one fuch furface 

 doth not touch the other. 



Now/or a plain furface to touch a concave, every man feeth 

 is impoflible. Likewise for to convexe furfaces to touch oueano- 

 ther,they muft be allowed to touch either in a line or in a point* 

 which we have fhewed not to be a phyficall touching. And if a 

 convexe furface fhould be faid to touch a concave ; they nauft 

 touch all at once as we faid of plain furfaces ; and therefore the 

 fame impoflfibility will arife therein : fo that it is evidentsthat no 

 two furfaces moving perpendicularly towards one another, can 

 come to touch one another,if neither of them yieldeth, and 

 changeth its hew. 



Now then, if it be fuppofed that they come flidingly one over 

 another in the fame line; whereby, firft the very tips of the edges 

 come to touch one another; and ftill as you fhoove the upermort 

 on forwards, and that it flideth over more of the nether furface, 

 itgaineth to touch more of it. I fay that neither in thiscale do 

 they touch immediately one anotherrfor as fbon as the two firft 

 parts fliould meet, if they did touch, and that there were no air? 

 between them; they muft prefcntly become one quantity or body 

 as we havedeelared;and muft ftick firmly together, according to 

 their degree of denfity;and coniequently could noc be moved on 

 without ftill breaking afunder at every impulfe, as much of the 

 maflie body.,as were already made one by their touching. 



K 3 And 



