Icebergs are born every day in every month, but most of them remain in or near their native waters for a long time before they escape and wander to the great lanes of travel between here and Europe.
The bergs seen last summer are from two to ten years old—that is, they have had an existence individually for years, though the ice from which they are formed is much older, some of it possibly having been frozen first a thousand years ago.
Icebergs are born of glaciers, and four out of five of the floating bergs on the Atlantic come from Greenland. A glacier is a river of solid water confined in the depressions running down the mountain sides.
Soft and powdery snow falls upon the summits, and though some is evaporated, the yearly fall is greater than the yearly loss, and so the excess is pushed down the slope into the valleys which possibly at the time are covered with green and have afforded pasture lands for cattle.
The snow gathers in the high valleys and every day undergoes some degree of the change which finally transforms it into ice. Slowly, very slowly, in some cases only a foot every year, this frozen river flows downward. Nothing can stop it, nothing can even check it.
The process is the same in Switzerland and Greenland, only in Switzerland the glacier melts when it reaches the lower valley and feeds rivers; in Greenland the glacier slides into the ocean, breaks off and becomes an iceberg and floats away.
One of the incidents of an ordinary Alaskan cruise along the coast is to see the glaciers break off and fall into the water. They are far more beautiful than the finest of the glaciers of Switzerland, and in size they are so great that the largest Alpine glacier would make only a fair-sized nose, if it could be taken bodily and placed upon the face of one of the Alaskan giants.
At Glacier Bay icebergs are being born all the while. Muir Glacier, the largest that dips into the bay, presents a front of 5000 feet. It is 700 feet thick, five-sevenths of it being under water. It extends back for miles and miles.
Each day the central part moves 70 feet into the sea, the discharge every twenty-four hours being 140,000,000 cubic feet of clear ice. As this great quantity cracks into pieces from the glacier, the bergs of the North Pacific begin their life. The separation from the larger mass and the plunge into the sea cause terrific noises.
The interior of Greenland is a solid mass of ice. In fact, some people think that at about the central part of Greenland there is a high mountain, around whose sides there has grown through the centuries an enormous glacier, sending down in every direction branch glaciers that extend to the coast. It is known that the only part of the land which is not covered completely by ice is a narrow belt around the shore.