On a novel phenomenon in the diurnal inequality of terrestrial magnetism at certain stations

In this research the author dealt with data from the Magnetic Observatories at Greenwich, Falmouth, and Pawlowsk (Russia). The declination, the horizontal, and the vertical, forces of terrestrial magnetism are denoted by D, H, and Z respectively, and the horizontal force in the astronomical meridian by X. Diurnal inequality increments are designated by the prefix Δ. The formula for obtaining ΔX is ΔH cos D - HΔD sin D = ΔX, and the unit of force employed is 1 x 10-5 C. G. S. (1γ ). The factor for conversion of ΔD from minutes of arc to units ofγ (HΔD) is H sin 1′; hours are counted continuously from midnight to midnight, and in the attached diagrams the scale value employed is 1·85 mm. = 1γ .