The Arctic World

by Anonymous

Rendu, the Roman Catholic prelate, who first led the way to the discovery of the true nature of glaciers, says, very justly,—“The economy of the world would be soon destroyed, if at certain points accumulations of matter prevailed. The centre of gravity of the globe would be insensibly displaced, and the admirable regularity of its movements would be succeeded by disorder and perturbation. If the Poles did not send back to the Equatorial seas the waters which, reduced into vapour, issue daily from these burning regions, to be converted into ice in the Arctic and Antarctic Zones, ocean would be drained dry, and life would cease, as well as water, to circulate throughout our world. The Creator, however, in order to ensure the permanence of His almighty work, has called into existence the vast and powerful law of circulation, and this law the careful observer sees reproduced in all the economy of Nature. The water circulates from the ocean into the air, from the air it spreads over the earth, and from the earth it passes into the seas. The rivers return from whence they came, in order that they may issue forth anew; the air circulates around the globe, and, as it were, upon itself, passing and repassing successively at all the altitudes of the atmospheric column. The elements of every organic substance circulates in changing from the solid to the liquid or aëriform state, and in returning from the latter to the state of solidity or organization. It is not improbable that the universal agent which we designate under the name of fire, light, electricity, and magnetism, has probably also a circle of circulation as extensive as the universe. Should its movements ever be known to us more than they now are, it is probable that they would afford the solution of a host of problems which still defy the intellect of man. Circulation is the law of life, the method of action employed by Providence in the administration of the universe. In the insect, as in the plant, as in the human body, we find a circulation, or rather several circulations,—blood, humours, elements, fire, all which enter into the composition of the individual.”

However fanciful may be some of the amiable prelate’s speculations, it is certain that the glaciers obey this law of circulation. The snow-accumulations in the upper regions are to some extent reduced by the descent of the avalanches,—that is, of masses of snow and ice which detach themselves from the mountain-sides and dash headlong into the valleys below, where they are rapidly melted by the warmer atmosphere. But this would, in itself, be wholly insufficient. Another movement, at once more efficacious and more regular, is necessary; a movement which embraces the entire system of the ice-masses, and which carries the glaciers below the perpetual snow-line, so that every year they may give up a portion of their terminal extremities. The discovery of this general progression is one of the most fertile with which, of late years, the physics of the globe have been enriched.

Professor Tyndall rightly observes that there are numerous obvious indications of the existence of glacier-motion, though it is too slow to catch the eye at once. The crevasses change within certain limits from year to year, and sometimes from month to month; and this could not be if the ice did not move. Rocks and stones also are observed, which have been plainly torn from the mountain-sides. Blocks seen to fall from particular points are afterwards noticed lower down. On the moraines rocks are found of a totally different mineralogical character from those composing the mountains right and left; and in all such cases strata of the same character are found bordering the glacier higher up. Hence the conclusion that the foreign boulders have been floated down by the ice. Further, the ends or “snouts” of many glaciers act like ploughshares on the land in front of them, overturning with irresistible energy the huts and châlets that lie in their path. Facts like these have been long known to the inhabitants of the High Alps, who were thus made acquainted in a vague and general way with the motion of the glaciers. But Science cannot deal with generalities: it requires precise and accurate information; and this information, so far as the progression of the glaciers is concerned, has been obtained through the patient labours of Rendu, Charpentier, Agassiz, Desor, Vogt, Professor Forbes, Bravais, Charles Martins, Hopkins, Professor Tyndall, Colomb, John Ball, and Schlagintweit. Their experiments and observations have established the truth of certain immutable principles, and proved the existence of a general law of movement.

The accumulation of the débris hurled headlong by the mountains forms on the glacier-surface long lines of stone and earth, which are called moraines; these diverge in certain directions, according to the circumstances we now come to explain.

The landslips which occur on the banks or edges of the glacier give rise to the lateral moraines, which are enlarged and extended daily by the twofold effect of the fall of stones and débris, and the progressive movement which carries them along with the whole mass of ice. Towards the centre of the great glaciers, in almost every case, is found a medial moraine; the result of the encounter of the lateral moraines of two glaciers which have united into one. These superficial moraines participating in the movement of the glacier, each of their blocks eventually rolls to the foot of the terminal precipice, and thus a frontal moraine is formed on the very soil of the valley, like an embankment raised to prohibit the further advance of the ice. And, lastly, the bed of sand, gravel, pebbles, and detritus which is found beneath the glacier, and over which it glides, is called the profound moraine.

The furrows wrought by this last-named stratum on the bottom of the glacier-channels show the wonderful force of friction which the glacier exercises during its descent. The depths of these furrows depends entirely on the hardness of the débris carried down by the glacier, and the nature of the rocks submitted to the friction. The polish assumed by these rocks when they are sufficiently solid to resist the thunderous march of the glacier, indicates the enormous pressure which it exercises on the slopes of the valley through which it forces its way. This effort, bearing principally on the side of the rocks turned in the direction of their crests, impresses upon them a peculiar rounded form, so like the appearance of a flock of sheep (moutons) that De Saussure gave them the name of roches moutonnées.

Connected with the scientific evidence of the progressive movement of glaciers, a glacier in the Bernese Oberland will for ever be memorable. Two branch glaciers, the Lauteraar and the Finsteraar, unite at a promontory called the Abschwung to form the trunk-glacier of the Unteraar, which carries a great medial moraine along its colossal back.

Here in 1827, an “intrepid and enthusiastic” Swiss professor, Hugi, of Solothurm (or Soleure), erected a small cabin of stones for the purpose of observations upon the glacier. The hut moved, and he took steps to measure its motion. In three years, 1827 to 1830, it moved 330 feet downwards. In 1836 it had descended 2354 feet; and in 1841, it had accomplished a journey of 4712 feet. [This was at the rate of about 336 feet a year.]

In 1840, M. Agassiz, with some scientific friends, Messrs. Desor, Vogt, and Nicolieb, established themselves under a great overhanging slab of rock on the same moraine, and by means of side walls, and other appliances, constructed a rough abode which, because some of these men of science came from Neufchâtel, they named the “Hôtel des Neuchâtelois.”

In two years after its erection, Agassiz discovered that it had moved downwards no less a distance than 486 feet.