In the Vistula, the direct distance from the source to the mouth is 329 miles, and the real distance is 611 miles; the windings comprise, therefore, 280 miles, or about two-thirds of the air-line from extreme to extreme. It becomes able to receive a large number of tributaries, and its basin is enlarged to an area of 78,402 square miles, becoming one of the best-watered and most fruitful on the globe. In the Oder, the direct distance from the source to the mouth is about the same as in the Vistula. But while the latter frequently changes its course, running first northward, then eastward to the Sau, then northward again to the Bug, then westward to the Drewenz, and lastly northward, and so gains a very large basin of drainage, the former is unvarying in its course from southeast to northwest; so that the direct line drawn from extreme to extreme, as the bird flies, is nearly coincident with the actual course of the river. The windings do not, at most, comprise one-third of the whole length of the stream, and the basin drained by its tributaries is at least a third less than that of the Vistula, and is proportionately less valuable to the interests of the world. In the Elbe the air-line length is 394 miles, greater therefore, than that of the Vistula or the Oder; its length, including its windings, is about the same as that of the Vistula. The area of its basin lies therefore between the two, 61,320 square miles; it is more valuable, therefore, than that of the Oder, and less valuable than that of the Vistula. Still less striking in this respect are the Weser and the Ems; but the Rhine assumes a prominence, in relation to the value of its basin, greater than even the Vistula. The direct distance from the source of the Rhine to its mouth is 423 miles, the actual distance 705 miles; the windings comprise, therefore, more than two-thirds of the entire length of the stream. The number of tributaries is uncommonly large, the area drained is increased about 9855 miles beyond that of the Vistula; and the entire basin (88,257 square miles) is one which has been of the greatest import in the history of all central Europe. All the rivers and all the terrace lands of the globe exhibit the same relation which we have been briefly indicating in a few European ones; in some of the great rivers of the world they are to be traced on a scale of grandeur of which in those which have been touched upon scarcely a suggestion is given.