Page:Popular Science Monthly Volume 59.djvu/41

From Wikisource
Jump to: navigation, search
This page has been proofread, but needs to be validated.
31
THE AURORA AUSTRALIS.

through this dark segment, apparently as bright as those above, but the light is changed in color and there is frequently a kind of halo about them. The arc gradually grows in intensity and in breadth, and it also rises a little towards the zenith. The upper edge of the segment pales as its height increases. The arc has remained perfectly regular; its two ends almost touch the horizon, and they advance to the east and to the west, widening the distance between them and showing more and more the contour of a circle as the bow of light rises."

For the first hour no beams were discernible, but the whole display consisted of an almost uniform light of a delightfully soft, cream color.

 

PSM V59 D041 Successive displays of aurora australis.png

Successive Displays of an Austral Aurora. Evening of September 10, 1898.

 

At ten o'clock this arc was about 15° above the sea; it was about thrice the breadth of an ordinary rainbow, and its edges were clearly defined against the dark blue of the heavens. Up to this time an air of restfulness and repose was about the phenomenon, but now this began to change to an atmosphere of mysterious excitement. A wave of light rolled slowly from one side to the other. This wave soon took on the texture of torn lacework and was drawn to and fro, while the arc, which was less brilliant, remained as it had been before. At about eleven o'clock a second arc, somewhat narrower and less brilliant, appeared below the first. The play of drapery now vanished, but in