Walden's rule predibts that the specific conductivity, k, of solution of an electrolyte of a low molecular weight decreases with increasing viscosity of the solution, n. By analysing the experimental data, it was concluded that the hydrated volume of neutral substances added as visous-forming agent interrupts the transport of ions.When the viscous-forming agent is of a low molecular weight substance, the specific conductivity, k, decreases linearly, regardless of the kind of added substances, with the volume fraction of the hydrated solute, o, calculated from Einstein's equation, as shown in Fig. 5.This means that the hydrated substance hinders the ionic transport.This theory is extended to the case of nonionic polymers, poly(vinyl pyrrolidone)(PVP) and poly(vinyl alcohol)(PVA), the hydration numbers, N(mole H2O/base mole), were calculated to be 2-5 and 1.5-2.0, respectively, as shown in Fig. 8.It has been concluded that ions are transferred thr ugh the poly er coil and that only the volume occupied by hydrated polymers disturbs the transport of the ions and decreases the ionic mobility, while the velume of expanded polymer coils contributes to the viscosity of these polymer solutions.Both hydration number, N, and intrinsic viscosity, [n], decrease in accordance with the lyotropic series as shown in Figs. 9 and 10. ln the case of LiCl'and Na2SO4, however, the ppparent.abnormality of hydration number was observed because the radii .of these hydrated.ions are large.