On Possibility of Coulomb Interaction between Masses and Electrical   Charges
  From non-linear modification of Maxwell-Einstein theory, considered in (physics/9801031), follows modified Coulomb law for interaction between charged objects. Namely, if $(m, e)$ and $(m', e')$ are masses and charges of two objects, then the potential energy of interaction, $V(r) = [ee' - kmm' - \sqrt{k}(em' + e'm)]/r $, where $k$ is Newtonian constant. It follows, that the Earth should possess negative electric charge, $Q_E = - \sqrt{k} M_E$. Obtained result explains, why do primary cosmic rays consist mainly of positive charges. 
Dmitriy Palatnik