248 MR. THOMAS HOPKINS ON THE INFLUENCE 



In the northern hemisphere, there is no palpable wind 

 that blows southward from a latitude higher than 70° ; but 

 one can be traced in the Arctic region, from the mouth of 

 the Mackenzie River, in longitude 134° west, that blows 

 generally in the winter over the whole of the eastern 

 side of North America to the southern point of Flo- 

 rida, in latitude 27° and west longitude 80°. This wdnd 

 is, in its general direction, north-west. Here, then, we 

 have a case similar in character to that just named, of 

 air passing from the slowly rotating latitude of 70° to the 

 rapidly rotating parallel of 27°; but instead of the air 

 being left behind by the more rapidly moving surface of 

 the earth through the 43° of latitude that it traverses, 

 and thus becoming an apparent easterly wind, it moves 

 faster than the surface through the whole 43° of latitude. 

 In the northern case the air had to pass over rough land, 

 presenting a surface likely to take the air with it ; but in 

 the southern it had to pass over water only ; yet in neither 

 case was the air left behind by the more rapidly rotating 

 surfaces of the earth. Now these two cases seem to be 

 sufficient to prove that air passing from slower to quicker 

 rotating parts is not liable to be left behind in the way 

 that has been so confidently assumed; and they warrant 

 us in inferring that it may possibly be an assumption that . 

 appeared to be found necessary to support a fallacious 

 theory, which seemed to some persons to account for im- 

 portant meteorological phenomena. 



It is, however, in accounting for the tropical trade-winds 

 that writers have been the most explicit in explaining the 

 retarding effect on winds of increasing rotatory velocity 

 of the surface of the earth. Kamtz, after stating that air 

 ascended in the tropics, and descended in the polar regions 

 to return to the tropics on the surface, says : — " On this 

 principle we ought to find a north wind in the northern 

 hemisphere, and a south wind in the southern; but these 



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