The most probable conjecture has fixed the cradle of our race in that corner of land which lies westward the steep range of the Beloot Tagh mountains, an off-shoot of the Himalayas, and northward from the high barren land of Cabul. This country, the ancient Bactriana, is the most habitable district to be found anywhere in Central Asia. There the hills stretch out in gentle slopes towards the west, and enclose fertile valleys, whose innumerable streams, fed by the mountains east and south, all go to swell the waters of the Oxus, now called the Jihon. Farther north lies another fruitful country, watered by the Jaxartes, separated from the first by a range of hills much inferior to those which divide both lands from Yarkand and Cashgar on the east, and from Cabul on the south. Both the great rivers empty themselves into the Sea of Aral, between which and the Caspian, sharply cutting off the fertile country from that sea, stretches the Khiva desert, a barren land affording a scanty nourishment to the herds of wandering Turkic tribes. There is good reason to believe, however, that this desert did not always exist, but that in times not extraordinarily remote the Caspian Sea, joined to the Sea of Aral, extended over a much larger area than it at present covers: it is known even now to be sinking steadily within its banks. With such a contraction of the great sea the desert would grow by a double process, by the laying bare its sandy bed and by the withdrawal of a neighbouring supply of moisture from the dry land. So it may well have been that the fruitful territory wherein in remotest ages were settled our Aryan ancestors, stretched so far west as to border upon a large inland Asiatic sea. It has even been conjectured that the turning of so much fertile land into desert was the proximate cause of those migrations which sent the greater part of the Aryan races westward--to people, at last, all the countries of Europe. The root which is common to the European languages for the names of the sea, means, in the Indian and Iranian languages, a desert: how can we account for this fact better than by supposing that after the European nations had left their early home, their brethren, who remained behind and who long afterwards separated into the people of India and Persia, came to know as a desert the district which their fathers had once known as the sea?