greater part of the Baltic Sea. At mid-winter, as seen from the moon, a vast white shield would reveal the Heartland in its largest meaning.
When the Russian Cossacks first policed the steppes at the close of the Middle Ages, a great revolution was effected, for the Tartars, like the Arabs, had lacked the necessary man-power upon which to found a lasting Empire, but behind the Cossacks were the Russian ploughmen, who have to-day grown to be a people of a hundred millions on the fertile plains between the Black and Baltic Seas. During the nineteenth century, the Russian Czardom loomed large within the great Heartland, and seemed to threaten all the marginal lands of Asia and Europe. Towards the end of the century, however, the Germans of Prussia and Austria determined to subdue the Slavs and to exploit them for the occupation of the Heartland, through which run the land-ways into China, India, Arabia, and the African Heartland. The German military colonies of Kiauchau and East Africa were established as termini of the projected overland routes.
To-day armies have at their disposal not only the Trans-Continental Railway but also the Motor-Car. They have, too, the Aero-
