Daylight Auroras

Abstract

ON Sunday, the 23rd July, at 7.40 P.M., there was visible from Blackpool a phenomenon which might readily be mistaken for a daylight manifestation of the Aurora. The phenomenon in question consisted of a number of parallel streamers of light rising vertically and situated from the observer in a north-westerly direction. That pottion of the sky occupied by these streamers would be about twenty-five degrees square, its lowest portion being about fifteen degrees above the horizon. At the time of the appearance the sun was obscured by a small but very dense cloud. Large masses of nimbus clouds occupied almost the whole of the north-western, northern, and north-eastern portion of the sky, whilst a few cumulus and cirro-cumulus clouds were visible in the eastern and southern parts of the heavens; one-twentieth part perhaps of the whole sky being apparently free from cloud. The streamers, which, like those ot the Aurora, were intermittent in intensity, contrasted greatly in direction with any proximate beams of the sun. The whole thing, however, I am strongly of opinion, was nothing more than a meteorological phenomenon of a very different nature from the Aurora; in short, I believe it was an unusual appearance attendant on a distant and somewhat singularly circumstanced rainfall. Immediately above the uppermost boundary of the space occupied by the streamers there was a large nimbus cloud entirely obscured from the sun's direct rays, whilst that part of the sky occupied by the streamers themselves was in a strong sunshine. The whole phenomenon lasted about half an hour, and my opinion that it was but an unusual aspect of a distant rainfall was strengthened by the fact of a heavy shower of rain descending immediately alter ihe disappearance of the streamers, the upper-current of the air being from the west by north. The rain-fall lasted about a quarter of an hour, and was accompanied by a double rainbow. When it had ceased that portion of the sky previously occupied by the streamers and almost half the remainder contained no visible trace of cloud.