The cause of the clearing, of course, was the falling temperature of the seas. Evaporation went on much less fast as the heat of the water lessened. The whole round of aquatic travel from ocean to air, and back to ocean again, proceeded at an everslackening pace. And here, if it so please geologists, may be found a reconciling of their demands for time to the relative pittance astronomy has been willing to dole them out, a paltry 50 or 100 millions of years, which like all framers of budgets they have declared utterly insufficient. For in early times the forces at work were greater, and by magnifying the means you quicken the process and contract the Earth's earlier eras to reasonable limits.
Upon these various astronomic novelties, the Earth on thus awakening looked for the first time. Such regard altered for good its own internal relations. The wider outlook made impossible the life of the narrower that preceded it. A totally changed set of animals and plants arose, to whom the cosmos bore a different aspect. The Earth ceased to be the self-centred spot it seemed before. As long ago as this had the idea that our globe was the centre of the universe been cosmically exploded. The Earth knew it if man did not.
Its denizens responded. The organisms that already inhabited it proceeded to change their character and crawl out upon the land. For in Devonian times the Earth was the home of fishes. The land was not con-
