II INDUCTION IN ROTATING SPHERES 93 We must accordingly replace— av au by V2N+ ax მე: ty 212 au Əz - aw by V2M+ ax (1), Tx Əy aw ǝv by V²L+ ax dy Iz მეს since ƏL ƏM ƏN + Эх ду + = -Χ (2). dz But now V2L and λ 210 = - V2M = V2N = = av - - - · 4πλ Απμ Απν aw Iz dy - ax (3), μ ₤10 Ө ע 814 = = მე aw a ax (4). дх dz dy au av ax ду да Əz If by these equations we eliminate L, M, N from the expressions (1), and add the forces directly exerted by the currents, that is av au дх - dy' etc., we get for the expressions, which are now to be substituted for ing:- av дх au ду etc., the follow- " (1+4π0( (: av au ax + дх dy Əz Vau aw ax (1+4π0) + (5). Əz да aw dy av ax (1+40) + dy Əz მე: The differ- ential equa. tions.