11 87 INDUCTION IN ROTATING SPHERES 2. In precisely the same way we may perform the investi- Value in gation for the space inside the spherical shell; we find - Q₁ = − (£) *A[ƒ:(r) sin iw + {1 − fi(r)} cos iw]Pnt Ω; the inside space. R Hence for the whole potential +x₁ = A{( {) "[ƒ¡(r) cos iw - ƒ½(r) sin iœ]P„- Li Xn R For vanishing angular velocities this expression reduces to X, for large ones to zero; more exactly for large values of we find by means of a formula which we have employed previously (p. 81) 1 2(2n+1) (2) ---- fi(r) +ƒ½(r) √ −1 = 2(2n+1) (R\" -- λμη - - € λ(S-s) = R 2(n+1)= n 1 7/ λμπ - dµ(R − r). -€-Aμ(R-r) Hence it follows that Li + Xn T μ - 5 (R-1 con (ias - - ~ - (R − r) Par € √2 2(2n+1)/p = A - (2)". n μη COS ίω 4 ni. behaviour Thus the internal potential diminishes with exceedingly great rapidity as the velocity increases. At the same time its equipotential surfaces exhibit the peculiarity of appearing turned through an angle proportional to the [square root of Peculiar the] angular velocity. As the velocity gradually increases of the mag- the forces conditioned by the potential take up successively netic forces all the directions of the compass; and this can be repeated side space. any number of times as the velocity goes on increasing. in the in- B. Heat Generated. Let R be the radius of a very thin spherical shell, and suppose that in it exists the current-function = Σψη