The reader may possibly wonder why the climate of the southern polar regions is so much more severe than that of the high northern latitudes; or why coasts and valleys, at equal distances from the equator, should in one case be found green with vegetation, and in another mere wastes of snow and ice; but the predominance of land in the north, and of sea in the south, fully answers the question. Within the Arctic Circle we see vast continental masses projecting far to the north, so as to form an almost continuous belt round the icy sea; while in the southern hemisphere, the continents taper down in a vast extent of open ocean. In the north, the plains of Siberia and of the Hudson’s Bay territories, warmed by the sunbeams of summer, become at that season centres of radiating heat, so that in many parts the growth of forests, or even the culture of the cereals, advances as high as 70° of latitude; while the Antarctic lands are of a comparatively small extent, and isolated in the midst of frigid waters, whose temperature scarcely varies from +29° 2´ even in the height of summer. Mostly situated within the Antarctic Circle, and constantly chilled by cold sea-winds, they act at every season as refrigerators of the atmosphere.
In the north, the formation of icebergs is confined to a few mountainous countries, such as the west coast of Greenland or Spitzbergen; but the Antarctic coast-lands generally tower to a considerable height above the level of the sea, and the vast fragments which are constantly detaching themselves from their glaciers keep up the low temperature of the seas.
In the north, the cold currents of the Polar Ocean, with their drift-ice and bergs, have but the two wide gates of the Greenland Sea and Davis’s Strait through which they can emerge to the south, so that their influence is confined within comparatively narrow limits, while the gelid streams of the Antarctic seas branch out freely on all sides, and convey their floating ice-masses far and wide within the temperate seas. It is only to the west of Newfoundland that single icebergs have ever been known to descend as low as 39° of latitude; but in the southern hemisphere they have been met with in the vicinity of the Cape of Good Hope (35° S. lat.), near Tristan d’Acunha, opposite to the mouth of the Rio de la Plata, and within a hundred leagues of Tasmania. In the north, finally, we find the Gulf Stream conveying warmth even to the shores of Spitzbergen and Nova Zembla; while in the opposite regions of the globe, no traces of warm currents have been observed beyond 55° of latitude.
Thus the predominance of vast tracts of flat land in the boreal hemisphere, and of an immense expanse of ocean in the Antarctic regions, sufficiently accounts for the æstival warmth of the former, and the comparatively low summer temperature of the latter.
It is unnecessary to describe in detail each of the desolate lands which modern navigators have discovered among the Antarctic ice-fields, but it may not be uninteresting to compare one or two of these dreary wastes with the lands of the north, situated in analogous latitudes.
The New Shetland Islands, situated between 61° and 63° of Southern latitude, were originally discovered by Dirck Gheritz, a Dutch navigator, who, in attempting to round Cape Horn, was carried by tempestuous weather within sight of their mountainous coasts. Long forgotten, they were re-discovered in 1819 by Mr. Smith, a master in the royal navy—whom a storm had likewise carried thither—and in the following year more accurately examined by Edward Bransfield, whose name survives in the strait which separates them from D’Urville’s Louis Philippe Land.
In 1829, the “Chanticleer,” Captain Forster, was sent to New Shetland for the purpose of making magnetic and other physical observations, and remained for several months at Deception Island, which was selected as a station from its affording the best harbor in South Shetland.
Though these islands are situated at about the same distance from the pole as the Faroe Islands which boast of numerous flocks of sheep, and where the sea never freezes, yet, when the “Chanticleer” approached Deception Island, on January 5 (a month corresponding to our July), so many icebergs were scattered about, that Forster counted at one time no fewer than eighty-one. A gale having arisen, accompanied by a thick fog, great care was needed to avoid running foul of these floating cliffs. After entering the harbor—a work of no slight difficulty, from the violence of the wind—the fogs were so frequent that, for the first ten days, neither sun nor stars were seen; and it was withal so raw and cold, that Lieutenant Kendal, to whom we owe a short narrative of the expedition, did not recollect having suffered more at any time in the Arctic regions, even at the lowest range of the thermometer. In this desolate land, frozen water becomes an integral portion of the soil; for this volcanic island is composed chiefly of alternate layers of ashes and ice, as if the snow of each winter, during a series of years, had been prevented from melting in the following summer, by the ejection of cinders and ashes from some part where volcanic action still goes on. Early in March (the September of the north) the freezing over of the cove in which the ship was secured gave warning that it was high time for her to quit this desolate port. With much difficulty and severe labor, from the fury of the gales, they managed to get away, and we may fully credit Lieutenant Kendal’s assertion, that it was a day of rejoicing to all on board when the shores of Deception faded from their view.
In 1775 Cook, on his second voyage, discovered the large island of South Georgia, situated in latitude 54° and 55°, a situation corresponding to that of Scarborough or Durham. But what a difference in the climate, for “we saw not a river or stream of water,” says the great navigator, “on all the coast of Georgia. The head of the bay, as well as two places on each side, was terminated by perpendicular icebergs of considerable height. Pieces were continually breaking off and floating out to sea, and a great fall happened while we were in the bay, which made a noise like a cannon. The inner parts of the country were not less savage and horrible. The wild rocks raised their lofty summits till they were lost in the clouds, and the valley lay covered with everlasting snow. Not a tree was to be seen, not a shrub even big enough to make a toothpick. The only vegetation was a coarse strong-bladed grass growing in tufts, wild burnet, and a plant like moss, which sprang from the rocks. The lands, or rather rocks, bordering on the sea-coast were not covered with snow like the inland parts, but all the vegetation we could see on the clear places was the grass above mentioned.” To find scenes of a similar wintry desolation, we must travel in the north as far as Nova Zembla or Spitzbergen, which are 20° or 24° nearer to the pole!
Thus the influence of the cold Antarctic waters extends far within the temperate zone. We can trace their chilling effects in Kerguelen Land (50° S. lat.), which when visited by Cook in the height of summer was found covered with snow, and where only five plants in flower were collected; in Tierra del Fuego (53° S. lat.), where the mean summer temperature is fully 9½° lower than that of Dublin (53° 21´ N. lat.); in the Falkland Islands (51° 30´), which, though flat and low and near Patagonia, have, according to Mr. Darwin, a climate similar to that which is experienced at the height of between one and two thousand feet on the mountains of North Wales, with less sunshine and less frost, but more wind and rain; and finally along the south-west coast of America, where the Peruvian current and the cold sea-winds so considerably depress the snow-line, that while in Europe the most southern glacier which comes down to the sea is met with, according to Von Buch, on the coast of Norway in lat. 67°; the “Beagle” found a glacier fifteen miles long and in one part seven miles broad descending to the sea-coast in the gulf of Penas, in a latitude (46° 50´) nearly corresponding with that of the Lake of Geneva.