6 THE LAW OF STORMS. 



observation, produces normal revolutions in accordance 

 with the law of gyration ; while, on the other hand, its 

 passage on the east side produces anomalous revolu- 

 lutions contrary to the law of gyration. When the 

 vortex of a whirlwind storm passes over the place of 

 observation, the vane may shift from one direction to 

 that immediately opposite to it. 



Generally, if the whirlwind storm is an equatorial 

 one in the Northern Hemisphere, it progresses from S. 

 E. to N. W. in the Torrid Zone ; it recurves at the outer 

 edge of the N. E. trade wind, and thence moves from 

 S. W. to N. E. But in the Southern Hemisphere an 

 equatorial storm moves first from N. E. to S. W.; re- 

 curves at the outer edge of the S. E. trade wind, and 

 then advances from N. W. to S. E. — bearing in mind 

 the direction of the rotation of the wind in each hemis- 

 phere, viz: against watch hands in the Northern, but 

 with watch hands in the Southern Hemisphere. Cer- 

 tain portions of the storms are characterized by certain 

 hurricane winds, and dividing the storm by diameters 

 drawn from the northern to the southern margin, and 

 again from the eastern to the western margin, we find 

 that in the Northern Hemisphere, on the northern 

 margin, the wind will be easterly ; on the eastern mar- 

 gin, southerly ; on the southern margin, westerly ; and 

 on the western margin, northerly ; — each portion of the 

 cyclone possessing its appropriate wind. 



The relations of the winds to the margin in the 

 Southern Hemisphere, will be exactly the reverse of 

 their relation in the Northern. Thus: It is the south- 

 ern margin of the storm south of the Equator, that 

 exhibits an easterly ; the western margin a southerly ; 

 the northern margin a westerly, and the eastern margin 



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