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In pearls and rubies rich the hawthorns show,
In such a case, prodigious mischief had been done to the woods, by the breaking down of vast arms of trees which were overloaded by the pressure of the encrusting ice. At other times, the seeming enchantment has been dissolved in a more gentle way:
For if a southern gale the region warm,
And journeys sad beneath the dropping trees.
As we advance farther into the arctic regions, we find them distinguished by more beautiful appearances of that phenomenon which we call the aurora borealis. In Shetland, these northern lights, which the natives call merry dancers, are the constant attendants of the clear evenings, and prove great reliefs amid the gloom of the long winter nights. They commonly appear at twilight, near the horizon, of a dun colour, approaching to yellow; sometimes continuing in that state for several hours, without any apparent motion; after which they break out into streams of stronger light, spreading into columns, and altering slowly into ten thousand different shapes, varying their colours from all the tints of yellow to the most obscure
russet. They often cover the whole hemisphere, and then make the most brilliant appearance. Their motions, at these times, are most amazingly quick; and they astonish the spectator with the rapid change of their form. They break out in places where none were seen before, skimming briskly along the heavens. On a sudden they are extinguished, and leave behind a uniform dusky
This again is illuminated in the same manner, and as suddenly left a dull blank. In certain nights they assume the appearance of vast columns; on one side of the deepest yellow, on the other declining away till it becomes undistinguished from the sky. They have generally a strong tremulous motion from end to end, which continues till the whole vanishes. In a word, we, who only see the extremities of these northern phenomena, have but a faint idea of their splendour and their motions.
In Siberia, there is one species of the aurora borealis, which regularly appears between the north-east and east, like a luminous rainbow, with numbers of columns of light radiating from it. Beneath the arch is a darkness, through which the stars appear with some brilliancy. This species is thought by the natives to be a forerunner of storms. There is another kind, which begins with certain insulated rays, from the north, and others from the north-east. They augment little by little, till they fill the whole sky, and form a splendour of colours rich as gold, rubies, and emeralds; but the attendant phenomena strike the beholders with horror; for they crackle, sparkle, hiss, make a whistling sound, and a noise even equal to artificial fire-works. The idea of an electrical cause is so strongly impressed by this description, that few persons retain any doubt of the origin of these appearances. The inhabitants on this occasion, say
it is a troop of men furiously mad, which are passing by. Every animal is struck with terror. Even the dogs of the hunters are seized with such dread, that they will fall on the ground, and become immoveable, till the cause is over.
In Hudson's Bay, moreover, the firmament, in winter, is not without its beauties. The night is enlivened by the aurora borealis, which spreads a thousand different lights and colours over the whole concave of the sky, not to be defaced even by the splendour of the full moon; and the stars are of a fiery redness. Mock suns and halos are not infrequent; they are very bright, and richly tinged with all the colours of the rainbow. The sun also rises and sets here with a large cone of yellowish light'.
Philosophers have speculated more frequently than successfully, upon the theory of the aurora borealis. The most satisfactory, which has yet been proposed, though that is not entirely free from objections, is the one of M. Libes. It has, however, been adopted by most of the northern philosophers, and may be concisely stated thus: The production of hydrogenous gas is next to nothing at the poles; therefore so often as the electricity is put into an equilibrated state in the atmosphere, the spark, instead of passing through a mixture of hydrogenous and oxygenous gas, as in our climate, passes through a mixture of oxy
1 Captain Monk, who wintered on the shore of Hudson's Bay, in the year 1619, relates, that the cold was so intense, that neither beer, wine, nor brandy, could resist it. These were all frozen, and the vessels which contained them were split into pieces; and, before they could use the liquors, they were obliged to hew them with hatchets, and dissolve them by fire. Virgil speaks of hewing wine, in his description of a Scythian winter;
Caduntque securibus humida vina.
genous and azotic gas: it must, therefore, cause a production of nitrous gas, nitrous acid, and nitric acid, which give birth to ruddy vapours, whose red colour will vary according to the quantity and proportion of those different substances which are generated. These vapours are carried towards the south where the air is most dilated, so that they approach more and more towards the spectator; and it is probable their motion may be assisted by a north wind. Sometimes they rise, as if to the zenith of the spectator, and then descend again towards the south: and a great number of causes may carry the vapours towards the different points of the heavens, whence origi nate the different motions taken by the aurora borealis, or its several parts. Lastly, the detona tions which are sometimes heard, depend upon the small quantity of hydrogenous gas, which is found in the upper regions of the atmosphere, and which combines with the oxygen to form water.
These principles, at the same time that they account, in M. Libes's estimation, for all the phe nomena accompanying the aurora borealis, explain also why it is so common towards the poles, and so rare in the temperate regions; while thunder, which is frequent in the torrid zone, is scarcely ever heard in the polar regions. The disengagement of hydrogenons gas is considerable near the equator, and very little towards the poles: and when we excite the electric spark in a mixture of hydrogen, oxygen, and azote, it combines, in preference, with the bases of the two former gases: the electric spark ought, therefore, to occasion thunder solely in hot countries, and to produce aurora boreales in cold countries.
But, to pursue our description, as we advance farther into these dreary regions, we may still meet with those picturesque objects, that can attract
and captivate the most incurious eye. In the icy seas, and particularly at Spitzbergen (which is the largest of that group of frozen islands, which go under that name, or that of New Greenland), the forms assumed by the ice are extremely pleasing. The surface of that which is congealed from the sea water (for we must allow it two origins) is flat, even, hard, and opaque, resembling white sugar, and is capable of being slid upon. The greater pieces, or fields, are many leagues in length: the smaller, are the meadows of the seals, on which those animals, at times, frolic by hundreds. The motion of the smaller pieces is as rapid as the currents: the greater, which are sometimes two hundred leagues long, and sixty or eighty broad, move slowly and majestically. They often fix, for a time, immoveable by the power of the ocean, and then produce, near the horizon, that bright white appearance, called by mariners the blink of the ice. The approximation of two great fields produces a most singular phenomenon: it forces the lesser (if that term can be applied to pieces several acres square) out of the water, and adds them to their surface: a second, and often a third, succeeds; so that the whole forms an aggregate of a tremendous height. These float in the sea like so many rugged mountains, and are sometimes five or six hundred yards thick; but the far greater part is concealed beneath the water. These are continually increased in height by the freezing of the spray of the sea, or of the melting of the snow which falls on them. Those which remain in this frozen climate, receive continual growth: others are gradually wafted by the northern winds into. southern latitudes, and melt by degrees, by the heat of the sun, till they waste away, and disappear in the boundless element.