A river that spreads out into the indeterminate earthform of a marsh is an effective barrier; but one that gathers waters into a natural basin and forms a lake retains the uniting power of a navigable stream and also, by the extension of its area and elimination of its current, approaches the nature of an enclosed sea. Mountain rivers, characterized by small volume and turbulent flow, first become navigable when they check their impetuosity and gather their store of water in some lake basin. The whole course of the upper Rhone, from its glacier source on the slope of Mount Furca to its confluence with the Saône at Lyon, is unfit for navigation, except where it lingers in Lake Geneva. The same thing is true of the Reuss in Lake Lucerne, the upper Rhine in Lake Constance, the Aare in Thun and Brienze, and the Linth in Lake Zurich. Hence such torrent-fed lakes assume economic and political importance in mountainous regions, owing to the paucity of navigable waterways. The lakes of Alpine Switzerland and Italy and of Highland Scotland form so many centers of intercourse and exchange. Even such small bodies of water as the Alpine lakes have therefore become goals of expansion, so that we find the shores of Geneva, Maggiore, Lugano, and Garda, each shared by two countries. Switzerland, the Austrian Tyrol, and the three German states of Baden, Wurtemberg and Bavaria, have all managed to secure a frontage upon Lake Constance. Lake Titicaca, lying 12,661 feet (3854 meters) above sea level but affording a navigable course 136 miles (220 kilometers) long, is an important waterway for Peru and Bolivia. In the central Sudan, where aridity reduces the volume of all streams, even the variable and indeterminate Lake Chad has been an eagerly sought objective for expanding boundaries. Twenty years ago it was divided among the native states of Bornu, Bagirmi and Kanem; today it is shared by British Nigeria, French Sudan, and German Kamerun. The erratic northern extension of the German boundary betrays the effort to reach this goal.
Lakes as nuclei of states.
The uniting power of lakes manifests itself in the tendency of such basins to become the nuclei of states. Attractive to settlement in primitive times, because of the protected frontier they afford—a motive finding its most emphatic expression in the pile villages of the early lake-dwellers—later because of the fertility of their bordering soil and the opportunity for friendly intercourse, they gradually unite their shores in a mesh of reciprocal relations, which finds its ultimate expression in political union. It is a significant fact that the Swiss Confederation originated in the four forest cantons of Lucerne, Schwyz, Uri and Unterwalden, which are linked together by the jagged basin of Lake Lucerne or the Lake of the Four Forest Cantons, as the Swiss significantly call it, but are otherwise divided by mountain barriers. So we find that Lake Titicaca was the cradle of the Inca Empire, just as Lake Tezcoco was that of the Toltecs in Mexico and an island in Lake Chalco later that of the Aztec domain.[745] The most stable of the short-lived native states of Africa have apparently found an element of strength and permanence in a protected lake frontier. Such are the petty kingdoms of Bornu, Bagirmi and Kanem on Lake Chad, and Uganda on Victoria Nyanza.
Large lakes, which include in their area islands, peninsulas, tides, currents, fiords, inlets, deltas, and dunes, and present every geographical feature of an enclosed sea, approach the latter too in historical importance. Some of the largest, however, have long borne the name of seas. The Caspian, which exceeds the Baltic in area, and the Aral, which outranks Lake Michigan, show the closest physical resemblance to thalassic basins, because of their size, salinity and enclosed drainage systems; but their anthropo-geographical significance is slight. The very salinity which groups them with the sea points to an arid climate that forever deprives them of the densely populated coasts characteristic of most enclosed seas, and hence reduces their historical importance. Their tributary streams, robbed of their water by irrigation canals, like "the shorn and parcelled Oxus", renounce their function of highways into the interior. To this rule the Volga is a unique exception. Finally, cut off from union with the ocean, these salt lakes lose the supreme historical advantage which is maintained by freshwater lakes, like Ladoga, Nyassa, Maracaibo and the Great Lakes of North America, all lying near sea level.
Lakes as fresh water seas.
Lakes as part of a system of inland waterways may possess commercial importance surpassing that of many seas. This depends upon the productivity, accessibility and extent of their hinterland, and this in turn depends upon the size and shape of the inland basin. The chain of the five Great Lakes, which together present a coastline of four thousand miles and a navigable course as long as the Baltic between the Skager Rack and the head of the Gulf of Bothnia, constitutes a freshwater Mediterranean. It has played the part of an enclosed sea in American history and has enabled the Atlantic trade to penetrate 1400 miles inland to Chicago and Duluth. Its shores have therefore been a coveted object of territorial expansion. The early Dutch trading posts headed up the Hudson and Mohawk toward Lake Ontario, as did the English settlements which succeeded them. The French, from their vantage point at Montreal, threw out a frail casting-net of fur stations and missions, which caught and held all the Lakes for a time. Later the American shores were divided among eight of our states. The northern boundaries of Indiana and Illinois were fixed by Congress for the express purpose of giving these commonwealths access to Lake Michigan. Pennsylvania with great difficulty succeeded in protruding her northwestern frontier to cover a meager strip of Erie coast, while New York's frontage on the same lake became during the period of canal and early railroad construction, a great factor in her development.
In 1901, the tonnage of our merchant vessels on the Great Lakes was half that of our Pacific, Atlantic and Gulf coasts combined,[ 746] constituting a freshwater fleet greater than the merchant marine of either France or sea-bred Norway. A remote but by no means faint echo of this fact is found in the five hundred or more boats, equally available for trade or war, which Henry M. Stanley saw the Uganda prince muster on the shore of Victoria Nyanza Lake. Ocean, sea, bay, estuary, river, swamp, lake: here is Nature's great circle returning upon itself, a circle faintly notched into arcs, but one in itself and one in man's uses.
NOTES TO CHAPTER XI