374 What is true of the sea in this respect may be claimed, also, though in a less degree, for the streams that carry the civilizing fruits of the coasts far into the interior. Nearly all large cities not situated on the harbors of coasts derive their importance from rivers; especially when they have been built on spots adapted by nature to the transhipment of merchandise. That Venice finally eclipsed Genoa is to be ascribed, in greatest part, to its control of an important stream, the Po. The economic importance of Holland, of Hamburg and Bremen will, in the long run, bear the same relation to one another as the geographical importance of the valleys of the Rhine, Elbe and Weser. As nothing is more disastrous to a nation than the loss of its coast (we need only cite the efforts of the Lybian kings and, later, of Philip of Macedon to conquer the Greek colonies on their coasts; and in more recent times, of Russia before Peter the Great, or of the Zollverein without the shores of the German sea), so, also, the economic and political influence of a stream increases as one approaches its mouth. Hence the justification of the great interest taken by Germany and Austria in the question of the Danubian principalities. The United States recognized this fact when they purchased Louisiana for 80,000,000 francs. _Bignon_, Hist. de France III, 111 seq. Readers of history are familiar with the important part played by the three Asiatic Mesopotamias: that between the Euphrates and the Tigris; that between the Ganges and the Brahmapootra; that between the Hoang-Ho and the Yang-tse-Kiang, to which finally the Punjab might be added. This relation is recognized by popular consciousness, in the case of the Ganges, by the belief in the sacredness of the stream. No river has had so much influence on civilization as the Nile: its periodical risings have made the labor of agriculture extraordinarily easy; their extent and regularity favored the progress of astronomy; the flooding over of the land led to geodesy; the hydraulic labors necessitated by the rising of the waters produced a school of architecture to which the river furnished an excellent means of transportation for the enormous masses to be moved. _K. Ritter_, Erdkunde, I, p. 880 seq; VI, p. 1,168 seq. In this matter, also, America and Europe have the advantage over Asia and Africa. While the Danube is, in places, scarcely three German miles from the Rhine—which, however, flows in an almost opposite direction—in Asia, the eastern streams are separated from the western, and the northern from the southern, by a strip of land difficult to be traveled, and about 300 German miles in extent. Besides, the principal streams of northern Asia have their exit into