A Probable Cause of the Yearly Variation of Magnetic Storms and Auroræ

Abstract

IN a previous number of this Journal (vol. lxvii. P- 377) an account was given of the very close relationship which seemed to exist between the epochs of the occurrence of prominences in the polar regions of the sun and Ellis's “great” magnetic disturbances. In a later number, (vol. lxviii. p. 257) it was shown that the presence of these polar prominences synchronised also with the appearances of large “polar” coronal streamers as seen during total solar eclipses. Disturbances near the solar poles seemed to play such an important rôle both in solar and terrestrial changes that an inquiry was made to find out whether any effect is felt on the earth when either of these solar poles is turned towards the earth during the course of the year. The result of such an investigation, recently communicated by Sir Norman Lockyer and the writer to the Royal Society, will here be briefly stated.