Application of Walden's rule to the electrical conduction of sea water

Although sea water is a relatively concentrated aqueous solution, Walden's rule still appears to be applicable to the variation of its electrical conductance with temperature. The variation of conductance with pressure, however, depends on the second power of viscosity rather than the first power as given by Walden's rule. The reduction of the sizes of hydrated ions is believed to be responsible. A fit of the observed pressure dependence of the electrical conductance of 35 per mil salinity sea water at 25°C is obtained if the value is corrected at 1 atmosphere for (a) the increased dissociation of MgSO4, (b) the decrease in the solution volume, and (c) the changes in viscosity. The last correction appears in the form of the second power of the reciprocal of the relative viscosity.