A Rare Phenomenon

Abstract

SUNDAY, the 13th August, and several days before, having been very hot and dry, a great deal of dust was suspended in the atmosphere, which caused without doubt the intense red colour of the setting sun, and might contribute to the phenomenon I am about to describe. This phenomenon may easily be understood by means of a globe bisected by a meridian plane, one half of it representing the celestial vault. Beginning at the eastern end of the equator, the space between the 40th and 50th degree of longitude may be tinged with reddish grey; then the space between the 60th and 75th degree, further, that between the 85th and 105th, and finally that between the 115th and 140th degrees. But the intensity of colour must vary inversely to the breadth of the stripes, and the three stripes left between the red ones be filled with a pretty vivid blue. This hemisphere placed upon a table with its southern pole pointing towards sunset, will afford a tolerable portrait of the aspect of the sky as it appeared immediately after sunset, and continued unchanged for more than a quarter of an hour. The stripes were not visible near the horizon, but were very distinct at an altitude of about fifteen degrees, and almost disappeared about the zenith. No cloud was seen during the occurrence of the phenomenon.