Switzerland’s grandest glaciers dwindle into insignificance beside the enormous ice-rivers of the frozen north. When the “Humboldt Glacier” of Greenland gets to the ocean it is about forty-five miles in width. A generous gift of water indeed, from land to ocean. Another monster glacier ends in a cliff of solid ice, rising in parts to four hundred feet of height. Greenland lies under one unbroken shield of snow and ice; and the weight of this tremendous “ice-cap” presses out numberless rivers of ice from its shores into the sea.
These do not, like Alpine glaciers, end in rivers of water, flowing through milder climates to the ocean. The Greenland glaciers themselves reach the sea, each thrusting an enormous “foot” far into deep water. For a while, as it does so, the glacier-ice holds firmly together in a solid mass, gliding slowly over the ocean-bed, getting deeper and deeper, till only a small part of it shows above the surface.
But ice naturally floats. The upward pressure of the sea becomes increasingly great, fighting against the tenacity of the ice, and in the end old Ocean has the best of the contest. A huge mass of ice snaps off from the glacier-foot and springs to the surface, making the waters seethe and swirl with the shock, and sending heavy waves in all directions. Then the buoyant mass floats away as a newly made Iceberg.
Some Icebergs, broken thus from a Greenland glacier, are two or three hundred feet high. That is to say, a sailor on board a ship can see two or three hundred feet of solid ice above the surface of the sea. But this is by no means the true iceberg height.
When we talk of ice “floating,” we do not mean that the whole piece of ice rests upon the top of the water. It floats in the water. Only about one-eighth of it is visible above, and the other seven-eighths are hidden below. So in the case of an iceberg rising two or three hundred feet above the sea, we may be sure that at least seven times as much ice is underneath the ocean-surface. This shows what an enormous mass the whole of a floating ice-mountain must be.
AN ICEBERG, SHOWING THE SECTION UNDER WATER
For every cubic foot of ice above water there are seven cubic feet below
Face page 86
No wonder that a certain iceberg, which held its head one hundred and fifty feet high, should have run aground in water five hundred feet deep! No wonder, either, that when two such bergs come together, and an unfortunate ship happens to lie between, it should be smashed like an egg-shell. In Baffin’s Bay Dr. Kane once counted a pack of two hundred and eighty bergs, most of them being between two and three hundred feet high.