steamer.  The grain barges of western Siberia, like the coal barges of the Mississippi, even within recent decades, are similarly disposed of at the journey’s end.[657] The tonnage of downstream traffic on the Ohio and Mississippi to-day greatly exceeds that upstream.  The fleet of 56 coal boats, carrying about 70,000 tons, which the great towboat Sprague takes in a single trip from Louisville down to New Orleans, all return empty.  Of the 15,226,805 net tons of freight shipped in 1906 on the Ohio system, 13,980,368 tons of coal, stone, sand and lumber were carried in unrigged craft, fitted chiefly for downstream traffic.[658]

[Sidenote:  Importance of mouth to upstream people.]

Owing to the strong pull exerted by a river’s mouth upon all its basin, current, commerce and people alike tend to reach the ocean.  For a nation holding the terrestrial course of a stream, the political fate of its tidal course or mouth must always be a matter of great concern.  To the early westerner of the United States, before the acquisition of the Louisiana country, it was of vital importance whether belligerent France or more amenable Spain or the Republic itself should own the mouth of the Mississippi.  Germany, which holds 240 miles (400 kilometers) of the navigable Danube,[659] can never be indifferent to the political ownership of its mouth, or to the fact that a great power like Russia has edged forward, by the acquisition of Bessarabia in 1878, to the northern or Kilia debouchment channel.[660] Such interest shows itself in sustained efforts either to gain political control of the mouth, or to secure the neutrality of the stream by having it declared an international waterway, and thus partially to deprive the state holding its mouth of the advantages of its transit location.

The only satisfactory solution is undivided political ownership.  After France pushed eastward to the Rhine in 1648, she warred for three centuries to acquire its mouth.  Napoleon laid claim to Belgium and Holland on the ground that their soil had been built up by the alluvium of French rivers.  Germany’s conquest of Schleswig-Holstein in 1864 was significant chiefly because it dislodged Denmark from the right bank of the lower Elbe, and secured undivided control of this important estuary.  The Rhine, which traverses the Empire from north to south and constitutes its greatest single trade route, gives to Germany a more vital interest in Holland than ever France had.  Her most important iron and coal mines and manufacturing industries are located on this waterway or its tributaries, the Ruhr, Mosel, Saar and Main.  Hence the Rhine is the great artery of German trade and outlet for her enormous exports, which chiefly reach the sea through the ports of Belgium and Holland.  These two countries therefore fatten on German commerce and reduce German profits.  Hence the Empire, by the construction of the Emden-Dortmund canal, aims to divert its trade from Rotterdam and Antwerp to a German