16 THE CLIMATOLOGY OF THE UNITED STATES. 



sessing the most favorable climatic conditions within the 

 temperate zone. The greatest inventors, generals, states- 

 men and authors and the leaders of civilization are the 

 product of the temperate zone. 



The heat and the cold of the torrid and frigid zones 

 enervate and stupefy men and retard development, so 

 likewise, to a less extent, extreme variations of tempera- 

 ture iu the temperate zone have an unfavorable influence. 

 We appreciate the fact that the degrees of heat or cold and 

 the dryness or dampness of the air affect invalids who are 

 frequently sent to other localities, according to the nature 

 of their trouble where these conditions are different ; but 

 it is also true that healthy persons are affected more or less 

 by all weather changes. Many are affected by changes in 

 temperature and others feel depressed during the passage 

 of an area of low barometer though they may not be able to 

 account for their feelings, therefore it becomes a matter 

 of more or less interest and importance to know somewhat 

 of other climates ; and we find a great variety in different 

 parts of the world. Some regions are very hot and others 

 very cold ; some have rain a large part of the year, in 

 others it seldom rains ; some are subject to great extremes 

 of temperature while others have very little change through- 

 out the year. In order to form an idea of the climate of 

 any given place we must know a few of the laws govern- 

 ing weather changes, and then with the addition of what- 

 ever statistics we may have, a tolerably accurate knowledge 

 of the climate can be obtained ; but if we seek that knowl- 

 edge blindly, by a few general reports, we are likely to 

 be misled. It is frequently noticed that, in geographies, 

 works of science and books of travel, the mean annual 

 temperatures of places are given ; such are worthless for 

 our purpose. As an example we might take the mean 

 annual temperatures of the two cities Sun Francisco and 



