Revolving about Fixed Axes. 



273 



by the motion of the particles of matter, the other excited by a 

 cause producing pressure, resisted by cohesion. Now, according 

 to the fundamental principles of mechanics, "the same cause 



Fiff. 4. 



D 



acting upon a body will either produce motion or pressure, ac- 

 cording as the body is free or restrained." And, "if two forces 

 act upon the same point of a body in different directions, a single 

 force may be assigned which, acting on that point, will produce 

 the same results as the united effects of the other two." Here 

 we have two forces acting on each particle of the revolving body, 

 but they are resisted by cohesion, therefore when cohesion ceases 

 to act, the effect of the two forces must be, according to the the- 

 orem of the composition of forces, to impel it in the direction of 

 their resultant, and with an amount of force equal to their me- 

 chanical equivalent ; — and experiment shows the correctness of 



