CHAPTER XL.
I AM not so ignorant about glacial movement, now, as I was when I took passage on the Gorner Glacier. I have "read up," since. I am aware that these vast bodies of ice do not travel at the same rate of speed: whilst the Gorner Glacier makes less than an inch a day, the Unter-Aar Glacier makes as much as eight; and still other glaciers are said to go twelve, sixteen, and even twenty inches a day. One writer says that the slowest glacier travels 25 feet a year, and the fastest 400.
What is a glacier? It is easy to say it looks like a frozen river which occupies the bed of a winding gorge or gully between mountains. But that gives no notion of its vastness. For it is sometimes 600 feet thick, and we are not accustomed to rivers 600 feet deep; no, our rivers are 6 feet, 20 feet, and sometimes 50 feet deep; we are not quite able to grasp so large a fact as an ice-river 600 feet deep.
The glacier's surface is not smooth and level, but has deep swales and swelling elevations, and sometimes has the look of a tossing sea whose turbulent billows were frozen hard in the instant of their most violent motion; the glacier's surface is not a flawless mass, but is a river with cracks or crevasses, some narrow, some gaping wide. Many a man, the victim of a slip or a misstep, has plunged down one of these and met his death. Men have been fished out of them alive, but
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