BENEFITS OF A FICKLE CLIMATE. 329 



often do we, who live in temperate latitudes, 

 vainly and thoughtlessly bemoan the incon- 

 stancy of the wind ! And yet there is un- 

 questionable wisdom manifest in the appoint- 

 ment of this very phenomenon. The masses 

 of human society, proportionally to the area 

 occupied by them in temperate regions, both 

 naturally and by artificial processes, vitiate 

 the air considerably more than do those of 

 tropical countries. Contrast, for example, the 

 purest atmosphere of England with that of 

 an American prairie, and while no chemical 

 difference in the quantities of ingredients might 

 be detected by our limited analysis, yet it is 

 positively certain, as a mere inference from 

 known facts, that the air of a country con- 

 taining upwards of sixteen millions of inhabitants 

 within a very limited area, possessing besides 

 immense manufactories, and consuming enormous 



* Q 



masses of fuel per annum, must be less pure 

 than that of a region where the eye in vain for 

 hundreds of miles seeks even the traces of a 

 human habitation. What, then, were the con- 

 dition of England, we may ask, but for her vari- 

 able winds ? 



In all probability, were there a constant cur- 

 rent from any quarter, it would not accomplish 

 anything like the amount of intermixture which 

 is effected by the shifting winds of which we so 



