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Once a Week (magazine)/Series 1/Volume 3/Auroras

AURORAS.

 

 

In primitive ages mystery alarmed. Knowledge of his insignificance amid the vastness of the universe inclined man to regard with superstitious awe the invisible but all-pervading forces of which he was vaguely conscious. Attributing to nature sympathy with his fortunes, he conceived that all phenomena had a direct relation to himself—that a mysterious connection existed between the events of his ephemeral life and the cyclical movements of the stars, and he uneasily sought in the complex changes of the heavens for indications of the future that might determine his faltering steps. From its weird and fantastic character the polar aurora is peculiarly adapted to elicit these emotions; and, as that seen by imagination is but the shadow of the actual projected into infinite space; so, in those ages of blood and havoc, the auroral coruscations, shaped by fearful fancy into aerial hosts contending with glittering arms, were conceived to portend proximate slaughters, which, from the spirit of the age, no sign from heaven was needed to presage. These phenomena no longer alarm us; and yet, beyond ingenious conjecture, modern science has made indifferent use of the materials accumulated by observation towards determining the real meaning or origin of auroras. Under these circumstances, the attention of the public having been attracted to late displays of singular brilliancy, and to the remarkable influence these have exercised upon telegraphic lines, some remarks may be acceptable on a subject scientifically so interesting, and, as affecting the chief means of international communication, so important to the welfare of our race.

After briefly reviewing the auroral phenomena, we propose inquiring what special conditions of the earth, atmosphere, or cosmos, ascertained to coincide with their occurrence, may be conceived to have a positive relation therewith either as cause or effect. Certes, coincidences do not in themselves constitute proofs of connection; but, when constantly recurrent, they justify a presumption to that effect, are fairly entitled to a valuation, and may possibly guide our efforts to discover the law they intelligibly suggest.

That which is specially perplexing in the aurora is the irregularity of its appearance. From earliest antiquity down to the present time it has been seen at unequal intervals, yet no period has been assigned to it, nor has anything been determined as to its law. The unknown writer of the book of Job speaks of the “Brightness that cometh out of the North.” Aristotle has recorded the phenomenon, and various other classical writers incidentally allude to it; but that it was then rare may be presumed both from the awe it inspired, and from the very position of that region whereto early science was restricted. To come to later times: in Sweden and the north of Europe it was also rare previous to the eighteenth century, and there seem to have been long intervals without any auroral appearances in England, though a lack of meteorological observations does not absolutely prove the absence of phenomena in an age indifferent to science, and inclined to prefer the comfort of repose to learned vigils. Of later years auroras have been remarkably vivid and frequent, even in places hitherto unvisited by them, for the great aurora of 1859 was the first ever observed in Jamaica since the discovery of that island.

It may be stated generally that auroras increase in frequency with proximity to the poles, but they are seen alike in the frosty winter of polar regions, and the autumn of more genial climes, the atmospheric serenity of those seasons being specially favourable to their visibility, and perchance to their occurrence. An aurora commences after sunset, rarely later than midnight, its duration varying from a few hours to several successive nights, while so manifold are its aspects and so rapid its transitions that they can scarcely be comprehended in a general description necessarily terse.

An aurora is always preceded by the appearance Page:ONCE A WEEK JUL TO DEC 1860.pdf/389 Page:ONCE A WEEK JUL TO DEC 1860.pdf/390 Page:ONCE A WEEK JUL TO DEC 1860.pdf/391