throughout Europe traces can be found of the Roman roads built nearly two thousand years ago. As the Roman Empire extended, these roads formed one of the chief means by which the lords of the world were enabled to preserve their conquests. By placing a legion in a central spot, where many of these roads converged, they were enabled to strike quickly in any direction and overawe the country. Stations were naturally built along these roads, and to the present day many of the chief highways of Europe follow the course of the old Roman roads. Our modern civilisation is in a large measure the outcome of this network of roads, and we can distinctly trace a difference in the culture of a nation where such roads never existed—as in Russia and Hungary, as contrasted with the west of Europe, where they formed the best means of communication. It was only in the neighbourhood of these highways that the fullest information was obtained of the position of towns, and the divisions of peoples; and a sketch map, like the one already given, of the chief Roman roads of antiquity, gives also, as it were, a skeleton of the geographical knowledge summed up in the great work of Ptolemy.
But of more importance for the future development of geographical knowledge were the great caravan routes of Asia, to which we must now turn our attention. Asia is the continent of plateaux which culminate in the Steppes of the Pamirs, appropriately called by their inhabitants "the Roof of the World." To the east of these, four great mountain ranges run, roughly, along the parallels of latitude—the Himalayas to the south, the Kuen-lun, Thian Shan, and Altai to the
