“…Herein, in the analysis of the mathematical relations of the densities of the resultant external forces, according to the properties of the ions, the forces due to their viscosity may be regarded or disregarded. In Fick's approximation [15][16][17][18], the viscosity for the charged components, in contrast to the neutral components, at condition (3) is not regarded; however, their formation, for example, according to [2,19], should be taken into account. Written macroscopic equations (15) may be obtained not only by the continuum mechanics methods described, for example, in [10,13], but also by microscopic methods in determination of the respective moments from the Boltzmann kinetic equation for the microparticle distribution functions [8,15].…”