HAIL STORMS. 339 



produced by " a highly electrical condition of 

 the atmosphere that the frozen masses were 

 kept in a state of reciprocating motion between 

 two clouds, oppositely charged with electricity, 

 until the mass rendered the force of gravity pre- 

 dominant ; or until the electric tension of the 

 cloud was exhausted by mutual reaction." In 

 his report on the present state of Meteorology, 

 Professor Forbes observes, that no better solution 

 has yet been offered to the world. (Transactions 

 of Jhe British Association, vol. i. 1832.) 



The leading facts connected with hail storms 

 are the following : 



1 . They are generally confined to the middle 

 latitudes, where masses of cold air, from the 

 polar regions, meet with warmer air from the 

 tropical latitudes, loaded with aqueous vapour. 

 When such currents encounter each other at the 

 usual height of spring and summer clouds, the 

 vapour of the warm air is condensed into cold 

 rains, or showers of small hail, but without much 

 lightning or violent wind : whereas all the most 

 destructive hail storms are accompanied with 

 tremendous flashes of lightning, and often with 

 fearful whirlwinds, or tornados. 



2. They occur chiefly during warm weather 

 in the United States, when the lower atmosphere 

 is* full of vapour, and heated for several hundred 

 miles to the temperature of 80, and sometimes 

 90 F. 



