Notes

Abstract

REFERRING to our inquiry (p. 488) as to disturbances of terrestrial magnetism during January and February, Dr. C. Chree writes from the Kew Observatory as follows:—“With the exception of some small movements on the 10th, our magnetic curves were very quiet from January 1 to 14; but thereafter there was a disturbed time, lasting over January 15 to 21. The disturbance was greatest from the 15th to the 18th—when it was well marked—less on the 19th and 20th, and still less on the 21st. The 22nd and 23rd were very quiet days. The rest of January was quiet generally, with a few small movements. February was quiet up to the 10th, with the exception of some slight movements on the 5th. From February 11 to 16 there was a moderately disturbed time; on the 20th and 21st there were some smaller movements. It was then quiet to the end of the month. ‘Quiet’ is, of course, only a relative word; there is seldom a day in which some slight movement, beyond the mere diurnal inequality, is not visible. In the case of the disturbances on January 15–21 and February 11–16, it was rather a case of numerous well-defined oscillations than of sudden comparatively isolated movements of a conspicuous character.”