If these historical events be followed on the map, the strategical fact of decisive meaning which emerges is that the continuous plains of the Great Lowland overlap from the Continental and Arctic drainage of the Heartland into the East of the European peninsula. There was no impediment to prevent the horsemen from riding westward into regions drained by such wholly European rivers as the Dnieper and Danube. In sharp contrast to this open passage from the Heartland into Europe is the system of mighty barriers which separate the Heartland along its eastern and south-eastern border from the Indies. The populous lands of China proper and India lie round the eastern and southern slopes of the most massive uplands on the Globe; the southern face of the Himalaya Range, curving for 1500 miles along the north of India, rises from levels at most only 1000 feet above the sea to peaks of 28,000 and 29,000 feet. But the Himalaya is only the edge of the Tibetan Plateau, which is as large as France, Germany, and Austria-Hungary put together, and of an average elevation of 15,000 feet, or the peak height of Mont Blanc in the Alps. As compared with such facts as these, the distinction between the lower uplands and the lowlands, between the
