The Ocean and Its Wonders

by R. M. Ballantyne

That the aurora dims the lustre of the stars seen through it, is a fact which was ascertained clearly by the same gentleman; and that it moves in a region beyond the clouds is also evident from the fact that when the latter covered the sky the aurora disappeared.

But some of the most singular appearances of the sea and sky in the polar regions are presented in summer. During that season the perpetual presence of the sun and the large tracts of ice floating about on the sea exert their opposing influences so as to produce the most astonishing results.

One part of the sea being covered with ice, produces a cold atmosphere; another part being free from ice, produces a warmer atmosphere. Refraction is the result of viewing objects through those different media, and very curious appearances follow. When Scoresby was in Greenland a singular atmospheric phenomenon occurred, whereby he became aware of the approach of his father’s ship some time before it rose above the horizon. He had reached Greenland before his father, who followed him in the Fame. The following is his account of the circumstance:

“On my return to the ship, about eleven o’clock, the night was beautifully fine and the air quite mild. The atmosphere, in consequence of the warmth, being in a highly refractive state, a great many curious appearances were presented by the land and icebergs. The most extraordinary effect of this state of the atmosphere, however, was the distinct inverted image of a ship in the clear sky, over the middle of the large bay or inlet, the ship itself being entirely beyond the horizon. Appearances of this kind I have before noticed, but the peculiarities of this were the perfection of the image, and the great distance of the vessel that it represented. It was so extremely well defined, that, when examined with a telescope, I could distinguish every sail, the general ‘rig of the ship,’ and its peculiar character; insomuch that I confidently pronounced it to be my father’s ship the Fame, which it afterwards proved to be, though, on comparing notes with my father, I found that our relative positions at the time gave our distance from one another very nearly thirty miles, being about seventeen miles beyond the horizon, and some leagues beyond the line of direct vision.”

Scoresby was, perhaps, one of the most persevering and intelligent observers of nature that ever went to the polar seas. His various accounts of what he saw are most interesting. We cannot do better than quote his remarks upon ice-blink, that curious appearance of white light on the horizon, whereby voyagers are led to infer the presence of ice:—

“This appearance of the ice-blink,” says he, “occurred on the 13th of June 1820, in latitude 76 degrees north. The sky aloft was covered with dense, uniform, hazy cloud, which indeed occupied the whole of the heavens, excepting a portion near the horizon, where it seemed to be repelled. The upper white blink referred to ice about six miles distant, being beyond the horizon; the narrow yellowish portions referred to floes and compact ice; the lowest yellow blink, which in brightness and colour resembled the moon, was the reflection of a field at the distance of thirty miles, to which, directed by the blink, we made way in the Baffin, through the channels of water represented in the sky by bluish-grey streaks. The field we found to be a sheet of ice 150 miles in circumference!”

Another very singular appearance observed occasionally in foggy weather is a series of bright circles, or coronae, surrounding the heads or persons of individuals in certain positions. We have, while standing at the mast-head of a vessel in Hudson’s Straits, observed our own shadow thrown on the sea with a bright halo round it. The day was bright and hazy at the time. Referring to a particular case of this kind, Scoresby says:

“During the month of July 1820, the weather being often foggy, with a bright sun sometimes shining at the height of the day, some extraordinary coronae 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-grey 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, etcetera. The colours of the whole three coronae 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 coronae I observed my own shadow, the head surrounded by a glory. All the coronae 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 coronae occur, in a great measure appears to consist.”

Mock suns, or parhelia, are common appearances in northern skies. Sometimes two of these mock suns are seen, one on each side of their great original, glowing so brightly that either of them, if we could suppose it to have shone in the sky alone, would have made a very respectable sun indeed! Even four of these “sun-dogs”—as they are some times called—have been seen surrounding the sun; one on each side of it, one directly above, and one immediately below, with a ring of light connecting them together, a streak of light passing horizontally and another passing perpendicularly between them, thus forming a luminous cross, in the centre of which was the sun itself. This magnificent spectacle is sometimes enhanced by a second circle of light enclosing the whole, and the edges of several outer circles springing in faint light therefrom until gradually lost, leaving the imagination to call up the idea of an endless series of glories extending over the whole sky.