Results of international magnetic observations made during the total solar eclipse of May 18, 1901, including results obtained during previous total solar eclipses

Abstract

During the total solar eclipse of May 28, 1900, a slight magnetic effect that appeared to be directly associated with the passage of the shadow cone from place to place was observed at various stations, distributed within or close to the belt of totality, in the southeastern part of the United States.1The analysis of the effect showed that it was not a phenomenon similar to a cosmical magnetic disturbance, the beginning of which takes place practically simultaneously over a very large area and, in many instances, over the entire earth, but that the occurrence of the various phases of the effect was closely related to the times of totality at the various stations. Furthermore, the indications were that the source of the effect was to be attributed to some change which occurred outside of the Earth's crust. It was also shown that this effect differed from an ordinary cosmical magnetic storm in that it began, progressed, and ended gradually; in brief, that it consisted of a wave of the periodic variation kind so that it was not proper to term it a “disturbance” or “perturbation,” but a magnetic oscillation or variation.