Gold Medal of the Royal Astronomical Society : Prof. S. Chapman, F.R.S.

Abstract

AT a meeting of the Royal Astronomical Society on February 11, the president, Prof. W. M. H. Greaves presented the Gold Medal to Prof. Sydney Chapman for his contributions to geophysics and solar physics and particularly to the theory of geomagnetic phenomena (see Observatory, April). Prof. Greaves referred particularly to Prof. Chapman's work on solar and lunar daily magnetic variations for the years 1902 and 1905, which were sunspot maximum and minimum respectively, as a result of which he showed that the field responsible for the solar and lunar daily variation could be separated into a predominant part originating on the surface of the earth and a lesser part originating inside the earth. He dealt with the researches by Prof. Chapman on magnetic storms, discussing especially the conclusions regarding the daily variations of forty magnetic storms—that the daily variations were additive to the normal daily variations—and to the deductions from these and certain other facts. Mention was also made of the theory of magnetic storms, formulated in 1931-32 by Chapman and Ferraro, which postulated a corpuscular stream emitted for a considerable time from a limited region of the solar surface. In this connexion, reference was made to Newton's work on solar flares, which does not support the view of Chapman and Ferraro on the comparatively long-lived streams. A note indicating the main lines of Prof. Chapman's work appeared in Nature of February 9, 1946, p. 155, when he was appointed Sedleian pro-fessorxo.f natural philosophy at Oxford.