On the lunar‐diurnal variation in the earth‐currents

In examining earth‐potentials at Jersey Marc Dechevrens twenty years ago found variations of tidal type, and in examining ordinary earth‐current observations the author demonstrated a lunar influence on the earth‐current potential‐gradient at Ebro, Spain, for the hours 10 to 11 a.m. In the following a complete determination of the lunar‐diurnal variation of the earth‐current potential‐gradient will be mentioned and discussed. The observational data —The data used for the present determination of the lunar‐diurnal variation of the earth‐current potential‐gradient are taken from the earth‐current observations made at Ebro in the period January 1 to December 21, 1910 (12 lunations). Only the data designated N→S, giving the potential‐gradient in a direction 25° west of north, have been examined.