THE WINDS. 27 



the earth, and from every thing upon the earth, 

 collect in the atmosphere, and, uniting together, 

 produce rain, snow, fog, and all other changes of 

 weather. 



WINDS. 



The winds which are continually blowing over 

 the earth are nothing but air put in motion chiefly 

 by means of heat. When any part of the air is 

 heated by the rays of the sun, or any other cause, 

 it is expanded and becomes lighter ; and as the 

 lightness causes it to ascend, it leaves a partial 

 void, into which the surrounding air rushes, to 

 fill up the void and restore the balance. For air, 

 like water and every other fluid, never rests until 

 it has found its level. This simple process, the 

 effects of which are very extensive, meeting with 

 various checks and interruptions from numberless 

 obstacles, causes those agitations of the air, which 

 are called wind. When the wind is violent, it is 

 called a storm, or tempest ; and when it is very 

 furious, a hurricane. Storms and hurricanes some- 

 times break and uproot the strongest trees, over- 

 throw houses, and lay waste large tracts of coun- 

 try. 



What is commonly called a high wind, which 

 does not amount to a storm, generally moves at 

 the rate of about thirty -five miles an hour ; and 

 in a hurricane the velocity of the wind is calcu- 

 lated at one hundred miles in an hour. 



