The Effect of Pressure upon the Dielectric Constants of Liquids

An empirical equation containing two parameters A and B is shown to express the isothermal variation of the dielectric constants of liquids with pressure. The equation is analogous to the Tait equation for the variation of the densities of liquids with pressure. The parameter B is common to both equations, and therefore may be determined independently from either dielectric constants or densities. Furthermore B can be eliminated between the two equations to give a linear relationship between the reciprocals of the dielectric constant and the density. It is shown that this linear relationship may be derived from Tammann's hypothesis and electrostatic theory.