108 CELESTIAL MECHANICS. I. i. 3. 



the result of all the forces combined, which is equal to 2»S 

 r^, the sum of the rotatory pressures of the separate forces, 



O'ZtT 



with respect to an axis parallel to z, and perpendicular to 

 the plane of x and y ; and this axis may be situated in any 

 imaginable direction with respect to the forces concerned, 

 the proposition holding good in all cases. 



