Clouds and Shadows

Abstract

ON the evening of Easter Monday I noticed in the western sky an effect which was unlike anything I had ever seen before. The sun was just setting behind a great bank of cloud, the rest of the sky being fairly clear, except for a thin veil of alto-stratus (it was not very high), which was moving at a good rate from the north-west, and stretched across the whole sky. This stratus was scarcely noticeable at first, as the sun's rays shining through it produced a milky kind of light in the sky. In startling contrast to this there appeared about halfway between the horizon and the zenith, to the south-west, what looked like an extraordinary “cloud”, which compelled attention. It was obvious, however, that this was no cloud, as it remained quite stationary, while the stratus (which I now observed) and also a few small lower clouds were driven quickly across the sky.