140 HURRICANES. [SECT. xv. 



hemisphere the body of the storm moves in exactly the op- 

 posite direction. The hurricanes which originate south of 

 the equator, and whose initial path is from N.E. to S.W., 

 bend round at the tropic of Capricorn, and then bend from 

 N.W. to S.E. 



The extent and velocity of these storms are great ; for in- 

 stance, the hurricane that took place on the 12th of August, 

 1830, was traced from the eastward of the Caribbee Islands 

 to the bank of Newfoundland, a distance of more than 3000 

 miles, which it passed over in six days. Although the hur- 

 ricane of the 1st of September, 1821, was not so extensive, 

 its velocity was greater, as it moved at the rate of 30 miles 

 an hour : small storms are generally more rapid than those of 

 greater dimensions. 



The action of these storms seems to be at first confined to 

 the stratum of air nearest the earth, and then they seldom 

 appear to be more than a mile high, though sometimes they 

 are raised higher ; or even divided by a mountain into two 

 separate storms, each of which continues its new path and 

 gyrations with increased violence. This occurred in the gale 

 of the 25th of December, 1821, in the Mediterranean, when 

 the Spanish mountains and the Maritime Alps became new 

 centres of motion. 



By the friction of the earth the axis of the storm bends a 

 little forward, so that the whirling motion begins in the 

 higher regions of the atmosphere before it is felt on the earth. 

 This causes a continual intermixture of the lower and warmer 

 strata of air with those that are higher and colder, producing 

 torrents of rain and violent electric explosions. 



The rotation is different in direction in different hemi- 

 spheres, though always alike in the same. In the northern 

 hemisphere the gyration is contrary to the movement of the 

 hands of a watch, that is to say, the wind revolves from east 

 round through the north to the west, south and east again ; 

 while, in the southern hemisphere, the rotation about the 

 axis of the storm is in the contrary direction. 



