PREFACE 



EVERY important aspect of human knowledge must be con- 

 sidered" mTits relation to both space and time. In 

 "Civilization and Climate" the problem of the effect of 

 physical environment upon human progress was discussed in its 

 relation to space. It was shown that the distribution of civiliza- 

 tion upon the earth's surface is closely in harmony with the dis- 

 tribution of climatic energy, which appears to be the most 

 important factor in physical environment. In the present volume 

 the same problem is considered in its relation., ta -iime. Beginning 

 with the present day we find that from year to year business 

 activities vary in extraordinary liarmony with health. Further 

 study shows that variations in health from year to year depend 

 upon the weather far more than upon any other single factor. 

 Turning to the distant past we find that from the earliest geo- 

 logical times the evolution of man's ancestors, even before they 

 had assumed the form of man, was largely guided by climatic 

 environment. This was especially true of mental evolution. 

 Periods of climatic stress not merely weeded out old types, but 

 apparently caused new types or mutants to arise, so that new 

 species and races came into existence. In historical times the 

 same extraordinarily close relationship between the air that men 

 breathe and the deeds that they do is apparent. Rome furnishes 

 a striking example. Turkey is today one of the world's most 

 puzzling problems partly because of the economic, physiological, 

 and political conditions arising from the uninvigorating climate 

 and the arid summers. Germany, in like manner, was able to defy 

 the world largely because no other country has so many people 



