Comparative Geography, which has pointed out so many relations between the terrestrial conditions of nations and their moral attainments, has laid great stress on the connection between the extent of sea-coast and a country's civilization. The sea line of Europe, compared with its area, is more extensive than that of any other continent, and Europe has had a more various and complete intellectual development than elsewhere. Africa, which has the shortest sea line compared with its area, has been most tardy in mental activity. The sea is the highway of nations and the promoter of commerce; and commerce, which brings different races together, awakens the intellect by the contact of different languages, religions, arts, and manners. Material civilization, it is true, does not commence on the sea-shore, but in river intervals. The arts of life were invented in the valleys of the Indus and Ganges, of the Yellow and Blue Rivers of China, of the Euphrates and the Nile. But the Phoenician navigators in the Mediterranean brought to the shores of Greece the knowledge of the arts of Egypt, the manufactures of Tyre, and the products of India and Africa. Every part of the coast of Greece is indented with bays and harbors. The Mediterranean, large enough to separate the nations on its shores, and so permit independent and distinct evolution of character, is not so large as to divide them. Coasting vessels, running within sight of land, could easily traverse its shores. All this tempted to navigation, and so the Greeks learned to be a race of sailors. What the shore line of Europe was to that of the other continents, that the shore line of Greece was to the rest of Europe. Only long after, in the Baltic, the Northern Mediterranean, did a similar land-locked sea create a similar love of navigation among the Scandinavians.[204] Another feature in the physical geography of Greece must be noticed as having an effect on the psychical condition of its inhabitants. Mountains intersected every part, dividing its tribes from each other. In numerous valleys, separated by these mountain walls, each clan, left to itself, formed a special character of its own. The great chain of Pindus with its many branches, the lofty ridges of the Peloponnesus, allowed the people of Thessaly, Boeotia, Attica, Phocis, Locris, Argolis, Arcadia, Laconia, to attain those individual traits which distinguish them during all the course of Greek history.