36 THE WORLD'S WONDERS. 



guish the most violent hurricanes or tornadoes. Whirlwinds 

 maybe formed by the rapid rotary movement of either ascending 

 or descending currents of air ; when the former occurs over a 

 body of water not infrequently water-spouts are the result, and 



A STEAMSHIP ENCOUNTERING A WATER-SPOUT AT SEA. 



at times so violent are these that at their base they have power 

 to wreck a small boat, and to lift an immense column of water 

 which is drawn upward with a noise like the rush of Niagara. In 

 cloud-bursts we have the very opposite, for they are produced by 



