The universal geography : earth and its inhabitants

LAKES AND RIVERS. 187St. Petersburg. It seems obvious that their progress northwards was checked bythe spongy nature of the soil, although this has partly been dried since the glacialepoch.Finland and the neighbouring tracts, where the ice held its ground longest,have remained largely lacustrine, the lakes in some places being more numerouseven than in Sweden. The dried land consists of isthmuses and narrow headlands,and all the hollows and depressions still remain filled with water. In this partlyflooded land are found the largest, but not the deepest, bodies of fresh water inEurope—Ladoga, Onega, Saima. Beyond this north-western territory lacustrinebasins occur here and there, but mostly already changed to peat beds and swamps.Since the retreat of the ice, the river alluvia on the one hand, and the mossygrowths on the other, gradually encroaching on the waters, have bad time to fillin nearly all the lacustrine cavities, and all the more easily that the geologicalformations of these districts lacked the resistingpower of the Finland granites.Thus have slowly disappeared such inland seas as that which formerly filled thespace now occupied by the Pripet marsh. Phenomena bearing witness to suchsuccessive changes are everywhere visible—in lakes here merely encroached uponby forests of reeds and turf banks, elsewhere reduced to a kind of tarn, " littlewindows " (okochki) with moss-grown borders ; others, again, changed to bogs, oralready partly converted into grassy tracts, orinvaded by stunted birch and pineforests venturing on the marshy soil, and gradually drying it up.As the lakes shrink up and disappear, the rivers grow in importance. Withthe exception of those of Finland, the Neva, and the Narova, all the great rivers ofRussia have acquired their fluvial character by draining the old lakes of theirbasins. Owing to the vast spaces they have to traverse before reaching the sea,they are fed by numerous affluents and swollen to considerable volumes, whichseem all the more so in proportion to their sluggish currents. Some are of greatlength, such as the Volga, exceeding all other European rivers in length, but notin the abundance of its discharge, as is often asserted, being in this respectsurpassed by the Danube. The rainfall is far less copious than in the west ofEurope, exposed to the moist Atlantic winds, and cannot be estimated at morethan 20 inches during the year.In their lower course the streams flowing to theEuxine, Sea of Azov, and Caspian traverse arid and treeless regions exposed to thefierce rays of the sun, and to the fury of the steppe winds.Hence the evaporationis here excessive, so that many rivers are absorbed by the soil and the air beforereaching their natural outlet. While ten times larger than France, Russiapossesses probably no more than three times the volume of its running waters.The Volga itself is lost in the Caspian basin, where it is entirely evaporatedwithout raising the level of that inland sea, long cut off from all communicationwith the ocean.Rising in regions but slightly above the sea-level, the larger rivers arenowhere separated from each other by elevated lands, and the chief obstacles tointercommunication have not been thehigh water-partings, but the swamps, peatbeds, vast forests, and solitudes. The rivers themselves, while facilitating inter-