Page:CunninghamPrinciple.djvu/6

Rh $$\therefore$$

(ii.) Surface Distribution.

In this case the integral $$\int\rho_{0}x\left(F_{x}\right)_{0}d\tau_{0}$$ becomes $$\int\sigma_{0}x\left(F_{x}\right)_{0}dS_{0}$$, over the surface of the sphere of radius a, and $$F_{x}=2\pi\sigma_{0}\cos\theta$$.

Thus

and