Page:Popular Science Monthly Volume 31.djvu/347

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THE NORTH AMERICAN LAKES.

and by its own work. The undertaking is chiefly in French hands, and we Germans have but little interest to favor the extension of French glory and success; but the divergencies which exist between nations should disappear in face of the great spirit of enterprise, which animates the director of the canal, M. de Lesseps, and in face of the private capital invested, which, though it be invested to promote private interests, has a general interest as well."[1]

Of such views it is safe to say that they are at least deserving of consideration. They are much to the credit of the writer, whose breadth of view and liberality of judgment alone enabled him to pen them.

 

THE NORTH AMERICAN LAKES.
By ISAAC KINLEY.

IN America, as in the Eastern Continent, the North is the land of lakes. A line from the mouth of the St. Lawrence to the western end of Lake Erie, and thence to the mouth of the Mackenzie, lies through and near a succession of lakes unequaled in number and aggregate area by any other like extent on the earth. The great North American depression, extending northward from the Gulf of Mexico, bifurcates at about the fortieth parallel, one branch trending northeastwardly to the Atlantic Ocean, and the other northwestwardly to the Arctic, lying nearly at right angles to each other, and in approximate parallelism to the mountain-ranges and shore-lines of the continent.

The forty-second parallel holds, to the north of it, nearly all the North American lakes, while to the south are numerous lake-basins, some of them rivaling even Superior in extent. These have been drained of their waters by the deepening channels of their effluent streams; or, as in the arid regions of the Southwest, by evaporation.

If we define a lake as, what geologically it actually is, a local digression of the surface, and treat the pressure or absence of water as only one of its accidents, we shall find the South, no less than the North, to be a land of lakes.

Lake-basins may be due

1. To local sinkings of the surface.
2. To excavations, notably by glaciers.
3. To the extinction of volcanoes, their craters filling with water.
4. To the breaking down of cave-roofs by earthquakes or other causes.

To the first and second of these agents are probably due nearly all the existing North American lakes, in some the one and in some the

  1. "Bulletin du Canal Interocéanique," December 1, 1886.