A Theoretical Discussion of the Electrical Properties of the Soil

Extract

It has been shown by Ratcliffe and White that the effective specific inductive capacity (ε) and the effective conductivity (σ) of soil placed, as dielectric, in a simple condenser vary in a marked manner with frequency. The range of frequency used was from 0·1 × 10⁶ cycles per second to 10 × 10⁶ cycles per second. It was found that at 6·1 × 10⁶ cycles per second the specific inductive capacity was very large (about 40 e.s.u.) and that it decreased to a value of about 12 e.s.u. at 10 × 10⁶ cycles per second. This latter value agrees with the value found in experiments on the propagation of short radio waves over the surface of the earth. The effective conductivity of the soil had a low value at 0·1 × 10⁶ cycles per second but increased rapidly to a constant value for frequencies above 3 × 10⁶ cycles per second.