§ 785, 78G. STORMS, HURRICANES, AND TYPHOONS. 417 



son of the year in wliicli the monsoons prevail in the North In- 

 dian Ocean, in the China Sea, and upon the Western coast of Cen- 

 tral America, all the seas of the northern hemisphere have the hur- 

 ricane season. On the contrary, the South Indian Ocean has its 

 hurricane season in the opposite season of the year, and when the 

 northwest monsoon prevails in the East Indian Archipelago. 



785. Under the head of hurricanes, typhoons, and tornadoes, I 

 The cyclone theory, includc all thosc galcs of wiud wliicli are known as 



cyclones. These have been treated of by Eedfield in America, 

 Beid in England, Tom of Mauritius, and Piddington of Calcutta, 

 with marked ability, and in special works. I refer the reader to 

 them. The theory of this school is, that these are rotary storms ; 

 that they revolve against the hands of a watch in the northern, 

 and with the hands of a watch in the southern hemisphere ; that 

 nearer the centre or vortex the more violent the storm, while the 

 centre itself is a calm, which travels sometimes a mile or two an 

 hour, and sometimes forty or fifty ; that in the centre the barom- 

 eter is low, rising as you approach the periphery of the whirl ; 

 that the diameter of these storms is sometimes a thousand miles, 

 and sometimes not more than a few leagues ; that they have their 

 origin somewhere between the parallels of 10° and 20° north and 

 south, traveling to the westward in either hemisphere, but in- 

 creasing their distance from the equator, until they reach the par- 

 allel of 25° or 30°, when they turn toward the east, or " recur- 

 vate," but continue to increase their distance from the equator — 

 ^. e., they first travel westwardly, inclining toward the nearest 

 pole ; they then recurve and travel eastwardly, still inclining to- 

 ward the pole ; that such is their path in both hemispheres, etc. 



786. The questions why these storms should recurve, and why 

 PuzzUng questions, they should travcl as they do, and why they should 



turn luith the hands of a watch in the southern, and against them 

 in the northern hemisphere, are still considered by many as puz- 

 zles, though it is thought that their course to the westward in 

 the trade-wind region, and to the eastward in the counter-trades, 

 is caused by the general movement of the atmosphere, like the 

 whirls in an angry flood, which, though they revolve, yet they 

 are borne down stream with the currents as they do revolve. 

 The motion polarward is caused, the conjecture is, by the fact 

 that the equatorial edge of the storm has, in consequence of diur- 



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