II 105 INDUCTION IN ROTATING SPHERES Let nim¹ mgr 1 x, y, t sec be the components of the polarisation, € (number)¹ the dielectric constant. For x, y, we have the equations I = - - E ab дх + €X, Эф ນ -E +ey, ·24+ €Z, dx dy for p = R xx + xy + zz= ar dy dz 1 ++ = Əz 4π ♡²; Papi ape афі - 4 п др др Hence we have for Απε Vaxa ² = and for p = R (1+4πε) az + + 1+4πεθα dy Əz афі эфе 4 пе др др e = (xX+yY+zZ). P In external space we must have V² = 0. If X again be the nth term of the external potential we have, as above (p. 43) ax _ 2w + + მე dy Əz 28 az nz 2x + y + z = w({p¹²x² - n²x»). xX+y+zZ Əz The units are again such that 1/A, the velocity of light, does not occur. The corresponding magnitudes in magnetic measure are A²r, A²y, A²¿, A².