The wonders of the world

by John Loraine Abbott

AURORA BOREALIS AND AURORA AUSTRALIS.

These splendid meteors are generally considered as the result of a combination of the two powers of magnetism and electricity. When the light, or aurora, appears chiefly in the north part of the heavens, it is called the aurora borealis, or northern lights; and when chiefly in the south part, the aurora australis, or southern lights. Where the coruscation is more than ordinarily bright and streaming, which, however, seldom occurs in the north, it is denominated lumen boreale; and where these streams have assumed a decided curvature, like that of the rainbow, they are distinguished by the name of luminous arches.

The aurora is chiefly visible in the winter season, and in cold weather. It is usually of a reddish color, inclining to yellow, and sends out frequent coruscations of pale light, which seem to rise from the horizon in a pyramidal, undulating form, shooting with great velocity up to the zenith. It never appears near the equator; but of late years has frequently been seen toward the south pole. The aurora borealis has appeared at some periods more frequently than at others. This phenomenon was so rare in England, or so little regarded, that its appearance was not recorded in the English annals between a remarkable one observed on the fourteenth of November, 1554, and a very brilliant one on the sixth of March, 1716, and the two succeeding nights, but which was much strongest on the first night. Hence it may be inferred, that the state of either the air or earth, or perhaps of both, is not at all times fitted for its production.

The extent of these appearances is surprisingly great. The very brilliant one referred to above was visible from the west of Ireland to the confines of Russia, and the east of Poland, extending over, at the least, thirty degrees of longitude, and, from about the fiftieth degree of latitude, over almost all the northern part of Europe. In every place, it exhibited, at the same time, the same wonderful features. The elevation of these lights is equally surprising: an aurora borealis which appeared on the sixteenth of December, 1737, was ascertained, by means of thirty computations, to have an average hight from the earth of one hundred and seventy-five leagues, equal to four hundred and sixty-four English miles.

Captain Cook, in his first voyage round the world, observed that these coruscations are frequently visible in southern latitudes. On the sixteenth of September, 1770, he witnessed an appearance of this kind about ten o’clock at night, consisting of a dull, reddish light, and extending about twenty degrees above the horizon. Its extent was very different at different times, but it was never less than eight or ten points of the compass. Rays of light, of a brighter color, passed through and without it; and these rays vanished and were renewed nearly in the same time as those in the aurora borealis, but had little or no vibration. Its body bore south-south-east from the ship, and continued, without any diminution of its brightness, till twelve o’clock, when the observers retired. The ship was at this time within the tropic of Capricorn.

On the seventeenth of February, 1773, during his second voyage, Captain Cook speaks of a beautiful phenomenon that was observed in the heavens. “It consisted of long columns of a clear white light, shooting up from the horizon to the eastward, almost to the zenith, and spreading gradually over the whole southern parts of the sky. These columns even sometimes bent sideways at their upper extremity; and, although in most respects similar to the northern lights, (the aurora borealis of our hemisphere,) yet differed from them in being always of a whitish color; whereas ours assume various tints, especially those of a fiery and purple hue. The stars were sometimes hidden by, and sometimes faintly to be seen through the substance of these southern lights, aurora australis. The sky was generally clear when they appeared, and the air sharp and cold, the mercury in the thermometer standing at the freezing-point; the ship being then in fifty-eight degrees south.” On six different nights of the following month (March) the same phenomenon was observed.

LUMEN BOREALE, OR STREAMING LIGHTS.

On the eighth of October, 1726, uncommon streams of light were exhibited in every part of the heavens, about eight o’clock in the evening. They were seen throughout England, as well as in the southern parts of Europe. They were mostly pointed, and of different lengths, assuming the appearance of flaming spires or pyramids; some again were truncated, and reached but half-way; while others had their points reaching up to the zenith, or near it, where they formed a sort of canopy, or thin cloud, sometimes red, sometimes brownish, sometimes blazing as if on fire, and sometimes emitting streams all around it. This canopy was manifestly formed by the matter carried up by the streaming on all parts of the horizon. It sometimes seemed to ascend with a force, as if impelled by the impetus of some explosive agent below; and this forcible ascent of the streaming matter gave a motion to the canopy, and sometimes a gyration, like that of a whirlwind. This was manifestly caused by the streams striking the outer part of the canopy; but if they struck the canopy in the center, all was then confusion. The vapors between the spires, or pyramids, were of a blood-red color, which gave those parts of the atmosphere the appearance of blazing lances and bloody-colored pillars. There was also a strange commotion among the streams, as if some large cloud or other body was moving behind and disturbing them. In the northern and southern parts the streams were perpendicular to the horizon; but in the intermediate points they seemed to decline more or less in one way or the other, or rather to incline toward the meridian. Several persons declared, that in the time of the streaming, they heard a hissing, and in some places a crackling noise, like that which is reported to be often heard in earthquakes.

At Naples, on the sixteenth of December, 1737, early in the evening, a light was observed in the north, as if the air was on fire, and flashing. Its intenseness gradually increasing, about seven o’clock it spread to the westward. Its greatest hight was about sixty-five degrees. Its extremities were unequally jagged and scattered, and followed the course of the westerly wind; so that for a few hours it spread considerably wider, yet without ever extending to the zenith. About eight o’clock, a very regular arch, of a parabolic figure, was seen to rise gently to two degrees of rectangular elevation, and to twenty degrees of horizontal amplitude. At ten the intenseness of the color disappeared; and by midnight not any traces of this phenomenon were left. It was seen throughout Italy, as the subsequent accounts will show. At Padua, on the appearance of this extraordinary meteor, the air was calm, and the barometer remarkably high. At five in the afternoon a blackish zone, with its upper limb of a sky-color, appeared near the horizon; and above this zone was another, very luminous, resembling the dawn pretty far advanced. The highest zone was of a red, fiery color. A little after six o’clock, the upper parts of these zones emitted an abundance of red streamings, or rays; their vivid color being occasionally intermixed with whitish and dark spots. In a few seconds after, there issued from the west, a red and very bright column, which ascended to the third part of the heavens, and a little after became curved like a rainbow. At half past eight, almost instantaneously, the bright zone, from eight degrees west to fifty degrees east, became more vivid, and rose higher; and above this appeared another and larger one, of a red, fiery color, with several successive streamings tending upward, and exceeding sixty degrees of altitude; the western part having assumed the form of a thin cloud. At midnight these splendid lights disappeared entirely. At Bononia, this surprising meteor spread to such an extent as to occupy about one hundred and forty degrees of the heavens. Its light was so vivid that houses could be distinguished, at eight in the evening, at a very considerable distance; and these were so reddened, that many persons thought there was a fire in the neighborhood. At that time the aurora formed itself into a concave arch toward the horizon; and in half an hour, at its eastern limit, a pyramid was displayed, of a more intense color toward the north, from the center of which there shot up vertically a streak of light, between a white and a yellow color. A very dark, narrow cloud crossed the whole phenomenon, and terminated in the pyramid. At the upper part, a very considerable tract of the heavens was enlightened by a very vivid red light, which was interrupted by several streaks or columns of a bright yellowish light. These streamings shot up vertically, and parallel to each other, the narrow cloud seeming to serve them as a basis. Under the cloud there issued forth two tails of a whitish light, hanging downward on a basis of a weak red, and seeming to kindle and dart the light downward. A white streak, which passed across these two tails, and extended from one end of the phenomenon to the other, in a position almost parallel to the above-mentioned cloud, gave a splendid effect to the whole. This surprising and beautiful meteor disappeared a short time after nine o’clock; but an abundance of falling stars were afterward seen in the south.

Similar observations were made at Rome; but in Great Britain, where this phenomenon was likewise seen, different appearances were displayed. At Edinburgh, at six in the evening, the sky appeared to be in flames. An arch of red light reached from the west, over the zenith, to the east, its northern border being tinged with a color approaching to blue. This aurora did not first form in the north, as usually happens, and after forming an arch there, rise toward the zenith; neither did the light shiver, and spread itself, by sudden jerks, over the hemisphere, as is common, but it gradually and gently stole along the face of the heavens, till it had covered the whole hemisphere: this alarmed the vulgar, and was indeed a strange sight. At Rosehill, in Sussex, it appeared as a strong and very steady light, nearly of the color of red ocher. It did not dart or flash, but kept a steady course against the wind, which blew fresh from the south-west. It began in the north-north-west, in the form of a pillar of light, at a quarter past six in the evening: in about ten minutes a fourth part of it divided from the rest, and never joined again. In ten minutes more it described an arch, but did not join at the top; and at seven o’clock it formed a bow, disappearing soon after. It was lightest and reddest at the horizon, and gave as much light as a full moon.