In the southeast there is no natural barrier between Russia and Asia; therefore the geographers have in turn taken the Don, the Volga, the Ural, or again the depression of the Obi, as boundaries. Desert steppes stretch from the centre of the old continent into Russia by the door left open between the Ural chain and the Caspian. From the lower course of the Don to the Aral Sea, all these low steppes on both banks of the Volga and the Ural rivers form the bed of an old, dried-up sea, whose borders we can still trace, and whose remnants constitute the great salt lakes known as the Caspian and the Aral seas. By a hydrographical accident which has had an enormous influence upon the character and destinies of the people, it is into one of these closed Asiatic seas that the Volga, the great artery of Russia, empties, after turning its back upon Europe almost from its very source. To the north of the Caspian steppes, from latitude 52° to the uninhabitable polar regions, the longest meridional chain of mountains of the old continent forms a wall between Russia and Asia. The Russians in olden days called it the “belt of stone,” or “belt of the world”; but, despite the name, the Ural indicates the end of Asia on the one side, only to mark its recommencement, almost unaltered, on the European slope. Descending gradually by terraces on the European side, the Ural is less a chain than a plateau crowned with a line of slight elevations. It presents principally low ridges covered with forests, like those of the Vosges and the Jura. So greatly depressed is the centre that along the principal passes between Russia and Siberia (from Perm to Iekaterinburg, for example) the eye looks in vain for the summits; in constructing a railroad through the pass the engineers had no long tunnels to build, no great difficulties to surmount. At this high altitude, where the plains are snow-bound during six or seven months, no peak attains the limit of eternal snows, no valley enbosoms a glacier. In reality the Ural separates neither the climates, nor the fauna and flora. Extending almost perpendicularly from north to south, the polar winds blow almost equally unhindered along both sides; on both, the vegetation is the same. It is not till the heart of Siberia is reached--the upper Yenisei and Lake Baikal--that one finds a different soil, a new flora and fauna. The upheaval of the Ural failed to wipe out the resemblance and the unity of the two regions it divides. Instead of a wall between the Russias, it is merely a storehouse of mineral wealth. In the rocks, of eruptive or metamorphic origin, are veins of metals not found in the regular strata of the great plains. It no more separates one from the other than does the river of the same name; and when one day Siberia shall boast a denser population, the Ural will be regarded as the axis, the backbone of the two great halves of the empire. THE DUALISM OF NORTH AND SOUTH