The universal geography : earth and its inhabitants

466 RUSSIA IN EUKOrE.2,000 Ions, though the mean burden is only from 150 to 1G0 tons. Most ofthese boats are built for a single voyage, after which they are broken up andsold as timber or fuel. Two-thirds of the river steamers ply on the Volga,representing three-fourths of the collective tonnage of all the inland navigation.Canals.— Railways.Of the 23,240 miles of navigable highways no more than one-sixtieth wasrepresented by canals in 1870; but some of these canals have a commercialFig. 251.Canals connecting the Baltic and Volga.Scale 1 : 5,080,000.importance equal, or even superior, to that of main rivers. Their construction hasbeen greatly facilitated by the marshy or lacustrine nature of the regions aboutthe upper courses of the main streams. The cuttings required to connect theVolga and Dvina by their head-streams have a total length of scarcely 9 miles ;while the Tikkvinskiy Canal, the shortest of those connecting St. Petersburg withthe Volga, crosses the crest of the water-parting by a cutting less than 10 miles