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Rh India, which still retain a waterful climate, are as populous as ever. Much of this is doubtless due to the overthrow of dynasties and the ensuing lapse of irrigation, but query: Is it all? For we have still more definite information in the drying up of the streams which have left the aqueducts of Carthage without continuation, as much to water on the one hand as to its drinkers on the other. Men may leave because of lack of water, but water does not leave because of dearth of men to drink.

Recent search around the Caspian by Huntington has disclosed the like degeneration due to encroaching desertism there. Indeed, it is no chance coincidence that just where all the great nations thrived in the morning of the historic times should be precisely where populous peoples no longer exist. For neither increasing cold nor increasing heat is responsible for this, seeing that no general change has occurred in either. Nor were they particularly exposed to extermination by northern hordes of barbarians. Egypt as a world power died a natural death, and Babylonia too; but the common people died of thirst, indirect and unconscious and not wholly of their own choosing. Prehistoric records make this conclusion doubly sure, by lengthening the limit of our observation. Both extinct flora and extinct fauna tell the same tale. In the neighborhood of Cairo petrified forests attest that Egypt was not always a wiped slate,