FRICTION IN MECHANICS. I95 



then will the points A, R, O, M, and N, coincide; 

 and according to Frifis principle, thetcnfions of RV, 

 VQ, and VP, will be equal; but, from the well-known 

 principle of the pulley, each cord VQ and VR bears 

 but half the weight P, and therefore this abfurdity fol- 

 lows, that a cord is as much ftretched with half the 

 weight as it would with the whoie. 



Again, if the points R, V, and Q, be fuppofed hori- 

 zontal, it follows, from the common theory, that the 

 tenfion of the rope RVQ would be infinite; but VN" 

 and VM vanifh when RVQ is horizontal; and there- 

 fore, by Frifis principle, the tenfion in that cafe would 

 be nothing at all ; but it is well known from the mofl 

 common experiments to be very confiderable, even 

 when RQV is but nearly horizontal; and therefore 

 the new theory of this great mathematician is indefen- 

 fible. 



Remark. All the foregoing, except the lad Scho- 

 lium, was written in 1775, before the Author had feen 

 any thing to fpeak of on the fubjecl. . He had defigned 

 and executed great part of an extenfive treatife on fric- 

 tion, according to different hypothefes ; but as nobody 

 would be at the rifk of publifhing it, and he could not 

 afford it himfelf, the moft of it was accidentally loll. 

 What is here given is an extract only of fome of the 

 fir ft part, where velocity was not taken into the ac- 

 count, and where there were no complicated algebraic 

 or fluxional exprefiions, which would be difficult to 

 print in this country. 



TO 



