S88 THE SCIENTIFIC MONTHLY
of the ancients^ of which little remains but a few ruined walla. The coast of Peru^ possibly as rainless a region as may be found, haa beneath its sands the remains of a people of unknown antiquity. The remarkable ancient city of Petra is situated in a peculiar many-colored rock-walled valley in the midst of a desert. It was wholly lost to the world for over a thousand years. On our own Atlantic coast, and else- where, we can readily follow the sand dunes as they travel inland, burying and destroying forests and villages. The known work of the wind, aided by sand, especially in a rainless, tropical region, suggests a natural agent of destruction — an enemy of man's handicraft that may be expected to certainly overtake and destroy, somewhere, some- time, the objects of art and culture that modern man has so carefully and painfully constructed.
Finally, we might make mention of the part man has taken in ac- complishiug the destruction of the works of his brother. War, disease, pestilence, the torch, starvation, and like allies of savage man, have wrought great destruction of material things, either directly or indi- rectly. The effects of fire have been referred to. War, hand in hand with disease and starvation, has leveled and depopulated many a city and country, and most often the victors in war have removed their loot and carried off their slaves, leaving the works of the vanquished people to lie uncared for and in ruins. Sometimes the fortunes were reversed, where a race or tribe of people who had been taken captive eventually carried out a successful rebellion, returned to the sites of their former cities, conquered or drove away any foreign race, and built their cities anew. In the course of time these cities were cast down in ruins once more.
Innumerable questions arise in the tracing of the fortunes of many peoples whom we moderns know only by the ruins and relics we have found. When we inquire into the reasons for the disappearance of a people, or the discontinuance of their civilizations, we can not always be sure that the proper agent or agents have been selected, since in the end the effects of several different agents may be so similar. Who were the Mound Builders, the Cliff Dwellers, the Toltecs, the Mayas, the Pre-Incas, the Cambodians, the mysterious dwellers of Easter Island? What was the origin of each of these peoples? In most cases we do not even know when or why they disappeared, much less their history. Were they exterminated or forced to migrate by natural agents, or by a conquering race? Have their works fallen to decay as a result of nature's behavior, or has nature been assisted by I
the hand of man? Doubtless, these and all similar questions wiU be fully and definitely answered sometime. But are we to wait until that time arrives before we are moved to consider the history of these and all such races, and leam one of the most serious lessons such considera- tion has to teach us?
�� �
