120 OUTLINES OF FORESTRY. 



than either the temperate or the polar regions, 

 because they receive the sun's rays more directly 

 than any other part of the earth. 



Regions of the earth that are situated the same 

 distance from the equator, however, often possess 

 different temperatures, not only because they are 

 exposed to warmer or colder currents of air or 

 water, but also on account of certain peculiarities 

 of their surfaces 



The distribution of the land and water areas of 

 the earth exerts a marked influence in causing a 

 difference in climate in regions situated in the 

 same latitude. 



A given quantity of the sun's heat falling on a 

 given area of water will produce therein a smaller 

 increase of temperature than if permitted to fall 

 on an equal area of land. Consequently, the air 

 over such body of water will be less warmed than 

 would the air over the land. 



"Water possesses a greater capacity for heat than 

 any other common substance; in other words, a 

 greater quantity of heat is required to cause a cer- 

 tain increase of temperature in a pound of water 

 than in a pound of any other common substance. 



For example : the quantity of heat required to 

 raise a pound of ice-cold water to its boiling-point, 



