Bodies affcBed by Tridiion, 



1 '^Q 





rx 



«r, confcqnently 



r$ -f rx ^ 



IX 



* • 



t S 



n r 



r i 

 rx 



(from what is proved above) 7;? x CB : /? x CA ; tberefor« 

 a X CA X r s ■]- a x CA x r x zz m x CB x r x^ hence rx^ 



— ~ — ^^^v the radius of the circle which rollinc^ down 



the incHned plane LM, and carrying the body with it, will 

 give the true ratio of its progreffive 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 ftraight line is already 

 very well known, it feems unnecedary to give the inveftigation. 

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

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

 ^lpon an horizontal plane, and affe6led by fri6Hon, be determined. 



