THE CASPIAN SEA PART OF THE ATLANTIC Although the Caspian Sea is in reality a vast salt-water lake, and does not belong to the Atlantic like the previous seas, still a few particulars respecting it may be of use to the student. This sea lies on the south-eastern borders of Europe, having Caucasia on its western, and Persia on its southern, shores. It is the largest strictly-inland expanse of water in the world, being 640 miles long, from 100 to 200 miles broad, and covering an area variously estimated at from 130,000 to 180,000 square miles. It was called a "sea" by the ancients, who erroneously supposed that it communi cated with the Northern Ocean ; but although it is certain that no such connection has existed within historic times, it is evident that this isolated expanse is simply "a survival of that great central sea which at no remote geological period covered a large part of North ern Asia—the gradual upheaval of land having separated it from the Black Sea, Sea of Aral, and the Arctic Ocean." The Caspian is also remarkable from the fact that its surface is below the general level of the waters of the globe.' The principal rivers flowing
into the Caspian are—the Volga (2,200 miles), the longest of all European rivers, the Ural (1,150 miles), Terek (300 miles), Kour (550 miles), and the Atrek. The supply of river and rain water seems to be exactly equal to the amount evaporated, for were it greater or less, a corresponding alteration of level would be the result. When first cut off from communication with the ocean, the level of the Caspian was doubtless the same as that of the ocean ; but once entirely enclosed, evaporation and supply being unequal— the former predominating—the level was gradually reduced, until it reached a point at which the waste and supply exactly counter balanced each other ; and so long as the present conditions exist unaltered, the present level will continue unchanged. The Caspian "has no tides ; its waters are slightly ; it is shallow, stormy, of difficult navigation ; and has but few indifferent ports"