port, and possibly thereby put the screw on Holland to draw her into some kind of a commercial union with Germany.[661] Heinrich von Treitschke, in his “Politik,” deplores the fact that the most valuable part of the great German river has fallen into alien hands, and he declares it to be an imperative task of German policy to recover the mouth of that stream, “either by a commercial or political union.”  “We need the entrance of Holland into our customs union as we need our daily bread."[662]

[Sidenote:  Prevention of monopoly of river mouth.]

When the middle and upper course of a river system are shared by several nations, their common interest demands that the control of the mouth be divided, as in the case of the La Plata between Argentine and Uruguay; or held by a small state, like Holland, too weak to force the monopoly of the tidal course.  The Treaty of Paris in 1856 extended the territory of Moldavia at the cost of Russia, to keep the Russian frontier away from the Danube.[663] Her very presence was ominous.  The temptation to giant powers to gobble up these exquisite morsels of territory is irresistible.  Hence the advisability of neutralizing small states holding such locations, as in the case of Roumania; and making their rivers international waterways, as in the case of the Orinoco,[664] Scheldt, Waal, Rhine and Danube.[665] The Yangtze Kiang mouth, where already the treaty ports cluster thick, will probably be the first part of China to be declared neutral ground, and as such to be placed under the protection of the combined commercial powers,[666] as is even now foreshadowed by the International Conservancy Board of 1910.[667] The United States, by her treaty with Mexico in 1848, secured the right of free navigation on the lower or Mexican course of the Colorado River and the Gulf of California.  The Franco-British convention, which in 1898 confirmed the western Sudan to France, also conceded the principle of making the Niger, the sole outlet of this vast and isolated territory, an international waterway, and created two French enclaves in British Nigeria to serve as river ports.[668]

[Sidenote:  Motive for canals in lower course.]

The mouth of a large river system is the converging point of many lines of inland and maritime navigation.  The interests of commerce, especially in its earlier periods of development, demand that the contact here of river and sea be extensive as possible.  Nature suggests the way to fulfill this requirement.  The sluggish lowland current of a river, on approaching sea level, throws out distributaries that reach the coast at various points and form a network of channels, which can be deepened and rendered permanent by canalization.  In such regions the opportunity for the improvement and extension of waterways has been utilized from the earliest times.  The ancient Egyptians, Chaldeans, East Indians, and the Gauls of the lower Po for thousands of years canaled the waters of their deltas and coastal