Auroral Display and Radio Disturbance

Abstract

THE probable occurrence of an aurora on January 7, twenty-seven days earlier than the notable display on February 3, as recorded in last week's issue of NATURE (p. 277), is confirmed by Mr. W. N. Craig, of The Manse, Fortrose, Ross-shire. On January 7, between 16Jh and 19h U.T., Mr. Craig, who was listening on the 14 Me. amateur band, found that reception from long-distance stations in South Africa and on the west coast of America, which was good at first, suddenly deteriorated at 18h 40m so as to render the signals practically unintelligible by “a very rapid flutter”. At 19h 30m, Mr. Craig, on looking outside, found that a conspicuous auroral display was in progress. An arch extending from north-east through north to west was beginning to break up into a series of streamers, and at 19h 45m, after an apparent increase in auroral activity, a corona formed for a few minutes a little to the northwest of the zenith. The display then decreased rapidly, but was partially renewed as a quiescent arch extending from east-north-east to west-northwest from 22h until after 23Jh. As mentioned in the previous note, the magnetic traces on January 7 recorded at the Greenwich magnetic station at Abinger show distinctive movements between 19h and 2011 U.T. The extreme ranges, occurring at about 19h 32m, indicate a local increase in the intensity of the earth's magnetic field of about 130 y accompanied by an easterly swing in declination of about 20′.