If you go to the end of the glacier, where it comes out into the lower valley, and look up to the icy cliffs which form the termination of it, and watch there for a few minutes, you soon see masses of ice breaking off from the brink and falling down with a thundering sound to the rocks below. This is because the ice at the extremity is all the time pressed forward by the mass behind it; and, as it comes to the brink, it breaks over and falls down. This is one evidence that the glaciers move.
But there is another proof that the ice of the glaciers is continually moving onward which is still more direct and decisive. Certain philosophers, who wished to ascertain positively what the truth was, went to a glacier, and, selecting a large rock which lay upon the surface of it near the middle of the ice, they made a red mark with paint upon the rock, and two other marks on the rocks which formed the shore of the glacier. They made these three marks exactly in a line with each other, expecting that, if the glacier moved, the rock in the centre of it would be carried forward, and the three marks would be no longer in a line.
This proved to be the case. In a very short time the central rock was found to have moved forward very perceptibly. This was several years ago. This rock is still on the glacier; and the red mark on it, as well as those on the shores, still remains. All the travellers who visit the glacier look at these marks and observe how the great rock on the ice moves forward. It is now at a long distance below the place where it was when its position was first recorded.
Then, besides, you can actually hear the glaciers moving when you stand upon them. It is sometimes very difficult to get upon them; for at the sides where the ice rubs against the rocks, immense chasms and fissures are formed, and vast blocks both of rock and ice are tumbled confusedly together in such a manner as to make the way almost impracticable. When, however, you fairly get upon the ice, if you stand still a moment and listen, you hear a peculiar groaning sound in the moraines. To understand this, however, I must first explain what a moraine is. On each side of the glacier, quite near the shore, there is usually found a ridge of rocks and stones extending up and down the glacier for the whole length of it, as if an immense wall formed of blocks of granite of prodigious magnitude had been built by giants to fence the glacier in, and had afterwards been shaken down by an earthquake, so as to leave only a confused and shapeless ridge of rocks and stones. These long lines of wall-like ruins may be traced along the borders of the glacier as far as the eye can reach. They lie just on the edge of the ice, and follow all the bends and sinuosities of the shore. It is a mystery how they are formed. All that is known, or rather all that can be here explained, is, that they are composed of the rocks which cleave off from the sides of the precipices and mountains that border the glacier, and that, when they have fallen down, the gradual movement of the ice draws them out into the long, ridge-like lines in which they now appear. Some of these moraines are of colossal magnitude, being in several places a hundred feet broad and fifty or sixty feet high; and, as you cannot get upon the glacier without crossing them, they are often greatly in the traveller's way. In fact, they sometimes form a barrier which is all but impassable.
The glacier which most impressed Mr. George and Rollo with its magnitude and grandeur was one that is called the Sea of Ice. It is called by this name on account of its extent. Its lower extremity comes out into the valley of Chamouni, the beautiful and world-renowned valley, which lies near the foot of Mont Blanc. In order to reach this glacier, the young gentlemen took horses and guides at the inn at Chamouni, and ascended for about two hours by a steep, zigzag path, which led from the valley up the sides of the mountain at the place which formed the angle between the great valley of Chamouni and the side valley through which the great glacier came down. After ascending thus for six or eight miles, they came out upon a lofty promontory, from which, on one side, they could look down upon the wild and desolate bed of the glacier, and, upon the other, upon the green, and fertile, and inexpressibly beautiful vale of Chamouni, with the pretty little village in the centre of it. This place is called Montauvert. There is a small inn here, built expressly to accommodate travellers who wish to come up and go out upon the glacier.
Although the traveller, when he reaches Montauvert, can look directly down upon the glacier, he cannot descend to it there; for, opposite to the inn, the valley of ice is bordered by cliffs and precipices a thousand feet high. It is necessary to follow along the bank two or three miles among stupendous rocks and under towering precipices, until at length a place is reached where, by dint of much scrambling and a great deal of help from the guide, it is possible to descend.
[Illustration: THE NARROW PATH.]
Rollo was several times quite afraid in making this perilous excursion. In some places there seemed to be no path at all; and it was necessary for him to make his way by clinging to the roughnesses of the rocks on the steep, sloping side of the mountain, with an immense abyss yawning below. There was one such place where it would have been impossible for any one not accustomed to mountain climbing to have got along without the assistance of guides. When they reached this place, one guide went over first, and then reached out his hand to assist Rollo. The other scrambled down upon the rocks below, and planted his pike staff in a crevice of the rock in order to make a support for a foot. By this means, first Mr. George, and then Rollo, succeeded in getting safely over.
Both the travellers felt greatly relieved when they found themselves on the other side of this dangerous pass.
In coming back, however, Rollo had the misfortune to lose his pike staff here. The staff slipped out of his hand as he was clinging to the rocks; and, after sliding down five or six hundred feet to the brink of the precipice, it shot over and fell a thousand feet to the glacier below, where it entered some awful chasm, or abyss, and disappeared forever.
Mr. George and Rollo had a pretty hard time in scrambling over the moraine when they came to the place where they were to get upon the glacier. When they were fairly upon the glacier, however, they could walk along without any difficulty. It was like walking on wet snow in a warm day in spring. Little brooks were running in every direction, the bright waters sparkling in the sun. The crevasses attracted the attention of the travellers very strongly. They were immense fissures four or five feet wide, and extending downward perpendicularly to an unfathomable depth. Rollo and Mr. George amused themselves with throwing stones down. There were plenty of stones to be found on the glacier. In fact, rocks and stones of all sizes were scattered about very profusely, so much so as quite to excite Mr. George's astonishment.
"I supposed," said he, "that the top of the glacier would be smooth and beautiful ice."
"I did not think any thing about it," said Rollo.
"I imagined it to be smooth, and glassy, and pure," said Mr. George; "and, instead of that, it looks like a field of old snow covered with scattered rocks and stones."
Some of the rocks which lay upon the glacier were very large, several of them being as big as houses. It was remarkable, too, that the largest of them, instead of having settled down in some degree into the ice and snow, as it might have been expected from their great weight they would have done, were raised sometimes many feet above the general level of the glacier, being mounted on a sort of pedestal of ice. The reason of this was, that when the block was very large, so large that the beams of the sun shining upon it all day would not warm it through, then the ice beneath it would be protected by its coolness, while the surface of the glacier around would be gradually melted and wasted away by the beams of the sun or by the warm rains which might occasionally fall upon it. Thus, in process of time, the great bowlder block rises, as it were, many feet into the air, and remains there perched on the top of a little hillock of ice, like a mass of monumental marble on a pedestal.[14]