THE ATMOSPHERE. 51 



than those near the equator, which have the sun more 

 directly overhead. 



2. Elevation. As the atmosphere is cooler the higher 

 we ascend, so the climate of elevajbed tracts is colder than 

 that of low plains and valleys. Although the high re- 

 gions receive the full benefit of the sun's heat, they lose 

 heat rapidly, since the atmosphere in these regions, be- 

 ing thin and dry, permits the heat to pass off easily by 

 radiation. 



3. Nearness to the Ocean. The tendency of the ocean 

 is to render the climate uniform, cooler in summer 

 and milder in winter. As the water upon the surface of 

 the ocean becomes heated by the sun, it mingles with 

 the cooler water below. This prevents the surface water 

 from becoming very warm, and from imparting heat rap- 

 idly to the atmosphere. 



As the ocean has stored a large amount of heat, and 

 has become heated to a considerable depth, it is not 

 quickly cooled as winter approaches, but parts with its 

 warmth gradually during the entire winter. 



The solid land, on the other hand, does not become 

 heated to a great depth. The heat of the sun is concen- 

 trated upon its surface, and is more readily radiated into 

 the atmosphere. 



In the fall of the year the ground is more quickly 

 cooled, and has less influence in tempering the severity 

 of winter. 



Near the coast, the climate is rendered comparatively 

 uniform by receiving the benefit of cool winds from the 

 sea in summer and mild winds in winter. 



The amount of moisture depends mostly upon the 

 nature of the surroundings and the direction of prevalent 

 winds. 



