Coil‐magnetometer and Earth‐inductor—A comparison of results obtained at the Abinger magnetic station of the Greenwich Royal Observatory

Abstract

Dr. J. Egedal, Danish Meteorological Institution, Copenhagen, has recently made an examination of the results obtained at a number of magnetic observatories in the northwest of Europe, with special reference to the magnetic vertical intensity, Z, as derived from observations with earth‐inductors. In the course of his investigation the values obtained in 1934 at Abinger, both with the inductor and with the Dye coilmagnetometer for directly determining Z, were compared, and it seemed to Dr. Egedal that discordances could most easily be explained as due to an effect of temperature in the magnetometer. He communicated this opinion to the Royal Observatory, Greenwich, and it was felt there that the matter deserved a closer investigation than would have been possible to anyone not having full details of the observing conditions.Accordingly the differences at Abinger in Z base‐line value as given by inductor and magnetometer have been analyzed, taking all days in the years 1934–37 on which determinations were made by both instruments.