Page:Popular Science Monthly Volume 76.djvu/163

Rh of primary importance. In polar and tropical regions, as well as in certain other isolated sections such as the deserts of central Asia, it is an absolute barrier to progress. Even in the most favored localities it has a marked effect upon the trend of social evolution. The invigorating effect of clear, cold weather is commonly recognized, but it is equally true that excessive moisture depresses the vital processes and thereby hampers development, an effect strikingly exemplified in the case of Ireland. On the other hand, dry weather if sufficiently prolonged creates a surplus of energy and at the same time weakens the emotional control, resulting, as shown by statistics, in a notable increase in misconduct and crime, apparent not only locally in times of drought, but habitually in dry countries like Mexico.

A remarkable synchronism of climatic changes has also been shown to exist throughout the world, recurring in cycles of approximately thirty-six years. In America this has made itself felt in the great financial crises, each of which has been associated with the deficiency in rainfall occurring at the low point of one of these cycles. This in turn has reacted upon politics to such an extent as to be of national import.

As yet the study of geographic influences in history has related only to such external and obvious manifestations as are apparent in social, industrial and political development. It may be interesting, therefore, to point out how these results may be extended to include intellectual development. In any attempt of this kind, it is necessary at the outset to set up some universal and fundamental principle of thought to serve as a standard for comparison of racial traits, and an index of mentality. Since racial traits become more distinct and divergent the more remote the period considered, few principles are sufficiently general to answer this purpose. There is, however, at least one form of thought which has always been characteristic of the human mind wherever historically manifested. Primitive culture, however remote, has always been accompanied by some form of mathematical reasoning. It is, in fact, noteworthy that all oriental nations ascribe the origin of both their culture and their mathematics to a single personage whom they also regard as the founder of their race. With the Chinese this was the Emperor Fohi, whose reign, about 2800 marked the beginning of Chinese history. As the Chinese have no earlier records to indicate the origin of their mathematics, their traditions relate that the number system was revealed to this emperor inscribed on the back of a dragon which rose from the waters of the Yellow River. In Egyptian history the first historical personage is the King Menes, who ruled somewhere between 5000 and 3000 and was the founder of the first dynasty of Pharaohs. Here also, from lack of earlier records, the Egyptians regarded Menes as the father of numbers, calculation and writing.