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A Pseudo-Aurora

1911; Nature Portfolio; Volume: 87; Issue: 2185 Linguagem: Inglês

10.1038/087347a0

1476-4687

J. S. GREY,

THE explanation which Sir Lauder Brunton calls for in No. 2183 of NATURE seems to be very simple indeed. On the evening of August 21, which he mentions, thunderstorms of extreme violence came over the region of Lugano and its environs. That region is due south-east of Beatenberg, as is also the Mnch. The flashes seen were most certainly those of lightning, and the auroral appearance is very easily explained. Anybody may, in a mountainous country, whenever there is a slight haziness in the atmosphere, remark the shadows thrown on the mist by a light—sun or moon—when still behind a mountain top, i.e. rather low down in the sky. Such was the case with the storm over Italian Switzerland, and the intense lightning on August 21 was noticed as far away as the Canton de Vaud. The flashes, lighting up the sky through the gaps between the mountains, with the corresponding dark rays of the shadows, following in uninterrupted succession, may well have given an impression of seeing auroral rays.