Chapter Eight.
The Cause of Ice-Bergs—Fox-Chase—A Bear.
One day, long after the walrus-hunt just described, Joe Davis stood on the deck of the Hope, leaning over the side and looking out to sea—at least in the direction of the sea, for, although mid-day, it was so dark that he could not see very far in any direction. Joe was conversing with Mr Dicey on the appearance of things around him.
“Do you know, Mr Dicey,” said he, “wot it is as causes them there ice-bergs?”
Mr Dicey looked very grave and wise for a few seconds without answering. Then he said, in rather a solemn tone, “Well, Davis, to tell you the real truth, I don’t know!”
Now, as this question is one of considerable interest, I shall endeavour to answer it for the benefit of the reader.
The whole of the interior of Greenland is covered with ice and snow. This snowy covering does not resemble that soft snow which falls on our own hills. It is hard, and never melts entirely away. The snow there is in some places a thousand feet thick! It covers all the hill-tops and fills up all the valleys, so that the country may be said to be a buried land. Since the world began, perhaps, snow has been falling on it every winter; but the summers there have been so short that they could not melt away the snow of one winter before that of another came and covered it up and pressed it down. Thus, for ages, the snow of one year has been added to that which was left of the preceding, and the pressure has been so great that the mass has been squeezed nearly as hard as pure ice.
The ice that has been formed in this way is called glacier; and the glaciers of Greenland cover, as I have said, the whole country, so that it can never be cultivated or inhabited by man unless the climate change. There are glaciers of this kind in many other parts of the world. We have them in Switzerland and in Norway, but not on nearly so large a scale as in Greenland.
Now, although this glacier-ice is clear and hard, it is not quite so solid as pure ice, and when it is pushed down into the valleys by the increasing masses above it, actually flows. But this flowing motion cannot be seen. It is like the motion of the hour hand of a watch, which cannot be perceived however closely it may be looked at. You might go to one of the valleys of Greenland and gaze at a glacier for days together, but you would see no motion whatever. All would appear solid, frozen up, and still. But notice a block of stone lying on the surface of the glacier, and go back many months after and you will find the stone lying a little further down the valley than when you first saw it. Thus glaciers are formed and thus they slowly move. But what has all this to do with ice-bergs? We shall see.
As the great glaciers of the north, then, are continually moving down the valleys, of course their ends are pushed into the sea. These ends, or tongues, are often hundreds of feet thick. In some places they present a clear glittering wall to the sea of several hundreds of feet in height, with perhaps as much again lost to view down in the deep water. As the extremities of these tongues are shoved farther and farther out they chip off and float away. These chips are ice-bergs! I have already said that ice-bergs are sometimes miles in extent—like islands; that they sink seven or eight hundred feet below the surface, while their tops rise more than a hundred feet above it—like mountains. If these, then, are the “chips” of the Greenland glaciers, what must the “old blocks” be?