Led on by such discrepancies, perhaps, he will want next to set his world of man in movement. He will thereupon perceive a circulation, so to speak, amongst the various peoples, suggestive of interrelations of a new type. Now so long as he is dealing in descriptions of a detached kind, concerning not merely the physical environment, but likewise the social adjustments more immediately corresponding thereto, he will be working at the geographical level. Directly it comes, however, to a generalized description or historical explanation, as when he seeks to show that here rather than there a civilization is likely to arise, geographical considerations proper will not suffice. Distribution is merely one aspect of evolution. Yet that it is a very important aspect will now be shown by a hasty survey of the world according to geographical regions. * * * * * Let us begin with Europe, so as to proceed gradually from the more known to the less known. Lecky has spoken of "the European epoch of the human mind." What is the geographical and physical theatre of that epoch? We may distinguish--I borrow the suggestion from Professor Myres--three stages in its development. Firstly, there was the river-phase; next, the Mediterranean phase; lastly, the present-day Atlantic phase. Thus, to begin with, the valleys of the Nile and Euphrates were each the home of civilizations both magnificent and enduring. They did not spring up spontaneously, however. If the rivers helped man, man also helped the rivers by inventing systems of irrigation. Next, from Minoan days right on to the end of the Middle Ages, the Mediterranean basin was the focus of all the higher life in the world, if we put out of sight the civilizations of India and China, together with the lesser cultures of Peru and Mexico. I will consider this second phase especially, because it is particularly instructive from the geographical standpoint. Finally, since the time of the discovery of America, the sea-trade, first called into existence as a civilizing agent by Mediterranean conditions, has shifted its base to the Atlantic coast, and especially to that land of natural harbours, the British Isles. We must give up thinking in terms of an Eastern and Western Hemisphere. The true distinction, as applicable to modern times, is between a land-hemisphere, with the Atlantic coast of Europe as its centre, and a sea-hemisphere, roughly coinciding with the Pacific. The Pacific is truly an ocean; but the Atlantic is becoming more of a "herring-pond" every day.