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These maps are taken from Butler's Pliilosopliy of the Weather, one of the 

 most practical books on meteorology, and one that should be studied by every 

 farmer desiring to learn the character of that atmosphere aa hich rules the pro- 

 ductiveness of the earth. 



The arrows in the trade-Avinds indicate the direction of the wind in them. 



Having stated thus briefly the machinery used for the distribution of moisture, 

 we proceed to show its action. 



The vast heat of the sun when it is directly overhead causes the atmosphere 

 beneath it to be intensely heated, and by this heat it is vastly expanded ; be- 

 coming lighter by this expansion, it ascends upward, causing a vacuum, which 

 is filled by the cooler air on each side of this heated and ascending atmosphere. 

 This movement creates other vacuums, which as they are filled causes a general 

 movement of the air from the poles to the equator. This moving of the atmos- 

 phere from cooler to more heated surfaces causes it to take up and retain vast 



