Chapter XVIII
The Historical Bearing
The contemporary life of any region is not a main object of study by the geographer alone; the record of it is of high value to the historian, who is thereby put in possession of far better material for an analysis of the life of the past. In the unfolding of civilization in the great cultural centers of the world there were an almost infinite number of stages and of types of environment. The effect of physical conditions Was now moderate, now great. To estimate such an effect requires the handling of geographical materials, and it still remains a fact that the accepted technique of historical re- search lays far too little stress upon geographical sources and particularly upon geographical method. The definitive history of South America will be written by that historian who knows best the geography of South America today, for in the present life in one place or another one may find illustrated virtually every stage that has passed. More than that, there is value in studying every important response to environment, no matter in what part of the world it may be displayed; for the flow of knowledge of plant life and of human organization tends in time to put new tools into the hands of men struggling against conditions whose conquest or amelioration has already been achieved elsewhere. This makes life not merely easier and hap- pier here and there as adaptation is carried forward more rap- idly; it makes it also more intelligent and conscious and there- by sets up all manner of secondary impulses that speed the progress of mankind.
The Desert of Atacama and the Puna de Atacama fall within one of the seven great regions of the world in which the population density is less than one inhabitant per square mile. Yet their effect upon life both settled and transient is an out- standing, indeed a vital, fact in the history and social develop-
ment of South America. Through their arid wastes streamed
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