ROTARY ACTION OF STORMS— TRACY 21 



pastures ; upon a black and charred clearing in the midst of a cool 

 forest ; or at a large clearing fire. Upon a great scale — if an island 

 beneath a tropical sun received upon rocks and sands the intense 

 radiance of a succession of clear, calm, and hot days, and conse- 

 quent sea breeees from the deep and cool ocean pressed in upon 

 all its shores with the violence of a high wind, it should not cause 

 surprise if these various breezes combined to generate a vast 

 whirlwind; nor if the lofty revolving column should at last leave 

 the place of its origin and traverse the sea, as a hurricane. The 

 cause which first excited the centripetal tendencies of the storm, 

 might be renewed as the upper currents of the atmosphere bore 

 it over other heated spots; and the law of deflection will inevitably 

 transform the central into circular motion. The destructive 

 storms of our sea-coast may have such an origin among the islands 

 of the West Indies, from which they appear to proceed. 



FIG. 3. 



In the southern hemisphere the same law of deflection produces 

 contrary results. There the wind which first moves north bends 

 to the west, and the wind which moves south at first turns towards 

 the east, that from the east turns south, and that from the west 

 turns north. Fig. 3 represents these effects. Hence south of 

 the equator storms revolve from left to right, or conformably to 

 the movement of watch hands. Fig. 4 exhibits the rotary action 

 of a storm in the northern hemisphere; fig. 5 the same in the south- 

 ern hemisphere. 



