Page:The evolution of worlds - Lowell.djvu/246

208 when we remember that the Moon has long turned the same face to the Earth. Her shape, therefore, has been that of an egg, with the apex pointing toward our world. Here the water would chiefly collect. The greater part of the seas she ever had should be on our side of her surface, the one she presents in perpetuity to our gaze.

It is to the heavens that we must look for our surest information on such a cosmic point, because of the long perspective other bodies give us of our own career. Less conclusive, because dependent upon less time, is any evidence our globe can offer. Yet even from it we may learn something; if nothing else, that it does not contradict the story of the sky. To it, therefore, we return, quickened in apprehension by the sights we have elsewhere seen.

The first thing our sharpened sense causes us to note is the spread of deserts even within historic times. Just as deserts show by their latitudinal girdling of the Earth their direct dependence upon the great system of planetary winds, as meteorologists recognizingly call them, so a study of the fringes of these belts discloses their encroachment upon formerly less arid lands. The southern borders of the Mediterranean reveal this all the way from Carthage to Palestine. The disappearance of their former peoples, leaving these lands but scantily inhabited now, points to this; because other regions, as