BoMes rfff5fcd by FridfJon. iSp 



-i X «r + /;Or='^^i^X«/', confequently "^"^ — ^; i :: is '. nr :: 



(from what is proved above) /«xCB:^7xCA; therefore 

 a X CA X r s + a x CA x r.v = f;2 x CB x r x^ hence r v =» 



.. ^^ " ^^{ the radius of the circle which roUina; down 

 mxCH— ^xCa ^ 



the inclined plane LM, and carrying the hody with it, will 

 give the true ratio of its progreliive to its rotatory motion, 

 and confequently that point of the circle which coincides with 

 any given point of the body will, as the circle revolves upon 

 the line LM, defcribe the fame curve as the correfponding 

 point of the body ; but as the nature of the curve defcribed by 

 any point of a circle revolving upon a flraight line is already 

 very well known, it feems unnecelTary to give the invefligation. 

 By a method of reafoning, not very different, may the nature 

 of the curve, which is defcribed by any point of a body moving 

 "Upon an horizontal plane, and affected by fridtion, be determined. 



