Spring arrives. The short but warm arctic summer bursts upon that vale, melting the surface of the snow; and the water thus produced sinks through the mass, converting it into a sort of thick slush—half snow, half water,—not liquid, yet not solid; just solid enough to lie there apparently without motion; yet just liquid enough to creep by slow, absolutely imperceptible degrees, down the valley. The snow in all the mountain gorges is similarly affected: it creeps (it cannot be said to flow) out and joins that in the vale. But we cannot perceive any of the motion of which we are writing. The mass of snow seems to be as still and motionless as the rocks on which we stand; nay, if we choose we may walk on its hard surface almost without leaving the slightest print of our foot. But if we throw a large stone on the surface of the snow and mark the spot, and return again after many days, we shall find that the stone has descended the valley a short distance. We shall also observe that the snow has now a variety of markings on its surface; which might lead us to fancy, had we not known better, that it had once been a river, which, while raging down to the sea with all its curling rapids and whirling eddies, had been arrested in all instant by the ice-king and frozen solid,—in fact, it has all the graceful lines and forms of fluidity, with all the steady, motionless aspect of solidity. It really moves, this vast body of snow; but, like the hour hand of a watch, its motion cannot be recognised, though we should observe it with prolonged, unflagging attention. We have called it a vast body of snow, but this is only comparatively speaking. It will be vaster yet before we have done with it. At present it is but a thick semi-fluid covering, lying at the bottom of this ancient arctic vale.
The brief summer ends. Much of the winter snow has been melted and returned to the sea; but much, very much more, is still lying deep upon the ground. The world’s second winter comes. The first frost effectually puts a stop to all the melting and moving that we have been describing. The snow-river no longer moves—it is arrested. The water no longer percolates through the snow—it is frozen. The mass is no longer semi-fluid—it is solid ice; and the first step in the process of a glacier’s formation is begun.
Thereafter this process is continued from year to year, each winter adding largely to its bulk, each summer deducting slightly therefrom. The growing mass of ice ascends the mountain-sides, swallows the rocks and shrubs and trees in its progress, until its body becomes a thousand feet thick: the extreme summits of the mountain-peaks alone tower above the snowy waste, and the mass at the bottom is now, by the pressure of superincumbent masses, pure ice, hard and clear as crystal.
When the great glacier grows old it still maintains its stealthy downward motion during every summer. It has reached the shore, and has been pushed, like a huge white tongue, out into the sea.
“But what has all this to do with icebergs?” it may be inquired. Much, very much. It is common enough, in commenting on a child, to speak of the parent. The glacier is the mother of the iceberg.
When, in the world’s early morning, the embryo glacier reached the sea, its thin edges were easily broken off by the waves; but as it increased and still further encroached, these edges became thicker and thicker, until at last a wall of pure ice, several hundred feet high, presented its glittering front to the ocean. It was hard and massive; the sun of summer had little effect on its frigid face, and it seemed to bid defiance to the sea itself. But things often are not what they seem. Each billow sapped its foundation; it soon began to overhang its base. At length the cohesion of the mass was not sufficient to sustain its weight. A rending, accompanied by sounds like heaven’s artillery, took place; the crystal mountain bowed its brow and fell with thunderous crash upon the water; then, rocking slowly under the impulse of its dread plunge, the first iceberg floated off to sea!
It is right to remark here that this explanation is, to some extent, disputed—at least there is a difference of opinion as to the manner in which the iceberg leaves its parent glacier. There is no dispute as to its origin. This difference will be explained shortly in a quotation from Dr Kane’s work; meanwhile, in support of the present theory, let us listen to the words of one who saw with his own eyes something similar to what has been described. Dr Scoresby, than whom a better man never explored the arctic seas, says:—
“In July 1818, I was particularly fortunate in witnessing one of the grandest effects which these polar glaciers ever present. A strong north-westerly swell, having for some hours been beating on the shore, had loosened a number of fragments attached to the iceberg, and various heaps of broken ice denoted recent shoots of the seaward edge. As we advanced towards it, with a view of proceeding close to its base, I observed a few little pieces fall from the top; and while my eye was fixed upon the place, an immense column, probably fifty feet square, and one hundred and fifty feet high, began to leave the parent ice at the top, and, leaning majestically forward, with an accelerated velocity fell, with an awful crash, into the sea.
“The water into which it plunged was converted into an appearance of vapour or smoke, like that from a furious cannonading. The noise was equal to that of thunder, which it nearly resembled. The column which fell was nearly square, and in magnitude resembled a church. It broke into thousands of pieces. This circumstance was a happy caution, for we might inadvertently have gone to the very base of the icy cliff from whence masses of considerable magnitude were continually breaking!”
Now, this incident suggests the probability, that, had the face of the glacier projected into deep water, the mass which broke off might have fallen into the sea without being broken to pieces, and might have floated away as a berg. We confess, however, to be partial to the view expressed by some writers, that the great glaciers continue year by year to thrust their thick tongues out to sea, until the projecting masses reach water sufficiently deep to float them, when they are quietly cracked off from their parent and carried away without any fall or plunge. The following remarks by Dr Kane will make this more clear. Writing of the iceberg, he says: