Optical Phenomena

Abstract

THE phenomenon described as “Cloud-Glow” by your correspondent, Mr. F. A. R. Russell, in NATURE of the 15th inst. (P. 55) and by Mr. J. J. Walker in your last issue (p. 77), was observed here by me; as, however, the time my observation commenced (5 p.m.) was three-quarters of an hour later than the time given by Mr. Russell (4.18 p.m.) it is probable that many of the features described by him had faded before the phenomenon came under my notice. As seen by me, the appearance consisted of an arc-like mass of glowing vapour of a ruddy hue, but of a tint not familiar to me, in the western horizon, exterding from the north-west to a point near the South Pole. The centre of the mass was about due west, and was there some 25° above the horizon. There was no wind; there were no cirri. The sky was clear and the air transparent, and I could not associate the appearance with anything like a “cloud-glow.” It seemed to me like the blaze of a great conflagration seen through a smoky medium, and I expected every moment to see the fire-engines rush past me. At dark (6 p.m.) there were long pallid streaks of polar auroral light, proceeding from a centre in the north-west. These presented no signs of the flickering activity usually accompanying auroral manifestations. Soon after 7 p.m. all traces of polar aurora vanished. It may be mentioned that, while instances of aurora have been common here throughout the autumn, on one occasion only have flashing rays and beams been present.