Page:The ocean and its wonders.djvu/206

 being often foggy, with a bright sun sometimes shining at the height of the day, some extraordinary coronæ were observed from the mast-head. These occurred opposite to the sun, the centre of all the circles being in a line drawn from the sun through the eye of the observer. On one occasion four coloured luminous circles were observed. The exterior one might be twenty degrees in diameter. It exhibited all the colours of the spectrum. The next, a little within it, was of a whitish-gray colour; the third was only four or five degrees in diameter, and though it exhibited the colours of the spectrum, these colours were not very brilliant. The fourth was extremely beautiful and brilliant. The interior colour was yellow, then orange, red, violet, &c. The colours of the whole three coronæ were, I think, in the same order, but of this I am not very certain. Indeed, on reflection, I suspect that the second circle must have been in the reverse order of the first; the first and the fourth being the same. The third was not coloured. In the midst of these beautiful coronæ I observed my own shadow, the head surrounded by a glory. All the coronæ were evidently produced by the fog; my shadow was impressed on the surface of the sea."

The cause of these phenomena is "the reflection of the sun's rays, decomposed by different refractions in minute globules of water, of which the mist, wherein the coronæ occur, in a great measure appears to consist."