The valleys which radiate in all directions from the great central masses of the Alps are admirably adapted for imparting to almost the whole of Europe a remarkable unity, whilst they offer, at the same time, an extreme variety of aspects and of physical conditions. The Po, the Rhone, the Rhine, and the Danube traverse countries having the most diverse climates, and yet they have their sources in the same mountain region, and the fertilising alluvium which they deposit in their valleys results from the disintegration of the same rocks. Minor valleys cut up the slopes of the Alps and of their dependent chains, and carry towards the sea the waters of the mountains and the triturated fragments of their rocks. Running waters are visible, wherever we cast our eyes. There are neither deserts, nor sterile plateaux, nor inland lakes and river basins such as we meet with in Africa and Asia. The rivers of Europe are not flooded as are those of certain portions of South America, which deluge half the country with water. On the contrary, in the scheme of her rivers Europe exhibits a certain degree of moderation which has favoured the work of the settler, and facilitated the rise of a local civilisation in each river basin. Moreover, although most rivers are sufficiently large to have retarded migration, they are not sufficiently so to have arrested it for any length of time. Even when roads and bridges did not exist, barbarian immigrants easily made their way from the shores of the Black Sea to those of the Atlantic. But Europe, in addition to the advantages due to its framework of mountains and the disposition of its river basins, enjoys the still greater advantage of possessing an indented coast-line. It is mainly the contours of its coasts which impart to Europe its double character of unity and diversity, which distinguish it amongst continents. It is “one” because of its great central mass, and “diversified” because of its numerous peninsulas and dependent islands. It is an organism, if we may say so, resembling a huge body furnished with limbs. Strabo compared Europe to a dragon. The geographers of the period of the revival of letters compared it to a crowned virgin, Spain being the head, France the heart, and England and Italy the hands, holding the sceptre and the orb. Russia, at that time hardly known, is made to do duty for the ample folds of the robe.