I34 A Twit fe of BODIES. Chap. n. 



j CHAP. XII. 



Of Violent Motion 



Jt A Ncl thus we have given a fhort fcamling, whereby to iin- 



Thc ftatc of Z~\derttand in feme meafure the caufcs of that motion which 

 thcqucfiicn ueca ll natural!, by rcafbn it hath its birth from the univerfall 



touching the r i i r \ 



caufe of violent oeconomy or nature here among us; that is, from the general! 

 n.oc.on. working of the funne, whereby all naturall things have their 



courfc: and by reafon that the caufe of it is at all times and in 

 all places conftantly the fame. Next unto which the order of 

 difcourfe leadeth us to take a furvey of thofe forced motions, 

 whofe firft caufes the more apparent they are,thc more obfcurity 

 they leave us in.to determine by what means they are continued 

 When a tennis-ball is ftrucken by a racket: or an arrow is 

 {hot from a bow, we plainly fee the caufcs of their motion : 

 namely the firings, which firft yielding, and then returning 

 ^ with a greater celerity, do caufc the miiTives to fpecd fo faft to- 



wards their appointed homes. Experience informeth us what 

 qualities the milfires mutt be endued withall to move faft and 

 fteadily. They muft be fo heavy that the. aire may not break 

 their courfe; and yet fb light, that they may be within the com- 

 mand of the ftroke which giveth them motion ; the ftriker muft 

 bedenfe, and in its beft velocity: the angle which the miflfivc is 

 to mount by ( if we will have it go to its furthcft randome ) 

 muft be the half of a right one : and laftly> the figure of the 

 miflive mutt be fuch, as may give fcope unto the airc to bear it 

 up, and yet not hinder its courfe by taking too much hold of it. 

 All this we fee; but wheq withall we fee that the mover dcfcrt- 

 eth the moveable afloon as he hath given the blow; we are at a 

 fland, and know not where to fcek for that which afterwards 

 maketh it flic: for motion being atranfient, not a permanent 

 thing,aflbon as the caufe ceafeth that begot it, in that very point 

 it muft be at an end; and as long as the motion continueth, 

 there muft be fbmc permanent caufe to make it do fo: fb that as 

 fobn as the racket or bowftring go back & leave the ball or ar- 

 row , why fhould not they prefently fall ftraightdown to the 

 ground ? 



i. Arittotle and his followers have attributed the caufe hereof 



7h. ihcmedi- to the aire: but Galileo rclifheth not this conception. His argu- 



um:s*eo a c T ^ 



