the passes and bayous of the river. The Barataria, Atchafalaya,
Terrebonne, Black, Teche and Lafourche bayous have been rendered
navigable, and New Orleans has been given canal outlets to the sea
through Lakes Salvador, Pontchartrain and Borgne.

[Sidenote: Watershed canals.]

As the dividing channels of the lower course point to the feasibility of
amplifying the connection with the ocean highway, so the spreading
branches of a river's source, which approach other head waters on a low
divide, suggest the extension of inland navigation by the union of two
such drainage systems through canals. Where the rivers of a country
radiate from a relatively low central watershed, as from the Central
Plateau of France and the Valdai Hills of Russia, nature offers
conditions for extensive linking of inland waterways. Hence we find a
continuous passway through Russia from the Caspian Sea to the Baltic by
the canal uniting the Volga and Neva rivers; another from the Black Sea
up the Dnieper, which by canals finds three different outlets to the
Baltic through the Vistula, Niemen and Duna.[670] The Northern Dwina,
linked, by canals, with the Neva through Lakes Onega and Ladoga, unites
the White Sea with the Baltic.[671] Sully, the great minister of Henry
IV. of France, saw that the relief of the country would permit the
linking of the Loire, Seine, Meuse, Saone and Rhine, and the
Mediterranean with the Garonne. All his plans were carried out by his
successors, but he himself, at the end of the sixteenth century, began
the construction of the Briare Canal between the Loire near Orleans and
the Seine at Fontainebleau.[672] Similarly in the eastern half of the
United States, the long, low watershed separating the drainage basin of
the St. Lawrence and Great Lakes from that of the Mississippi and the
Hudson made feasible the succession of canals completing the "Great
Belt" of inland navigation from St. Lawrence and New York bays to the
Gulf. Albert Gallatin's famous report of 1808[673] pointed out the
adaptation of the three low divides to canal communication; but long
before this, every line of possible canoe travel by river and portage
over swamp or lake-dotted watershed had been used by savages, white
explorers and French voyageurs, from Lake Champlain to Lake Winnebago,
so that the canal engineer had only to select from the numerous portage
paths already beaten out by the moccasined feet of Indian or fur-trader.

[Sidenote: Rivers an