Climate 183 



July and August ; and winter is less cold than it would 

 otherwise be, thanks to the heat gradually given back 

 by the great mass of earth. 



But the heat given back to the air in this way would 

 quickly escape, and benefit us little, were it not for the 

 moisture in the air, which acts the part of a blanket, 

 and keeps it near the earth. At the. equator, the air is 

 generally in a very moist condition all the year round ; 

 and this moisture, while serving the part of a blanket 

 by night, acts as a veil or parasol by day, and prevents 

 the sun's rays from being too scorching. 



It is to the large quantity of moisture in the air that 

 the region of the equator owes its very even tempera- 

 ture, therefore. 



In the dry plains of North India the heat is scorch- 

 ing, much greater than at the equator, just for want 

 of this veil ; and the nights are often so cold that water 

 is frozen, because the heat received by day all escapes 

 again through the clear air. 



Everybody knows that a clear night is a cold night, 

 while a misty or cloudy one is comparatively warm. 



Among other circumstances, therefore, which greatly 

 affect the climate of a country is its nearness to or dis- 

 tance from the ocean. For where constant evaporation 

 is going on, on a large scale, as, of course, it is from 

 the ocean, there the air must needs be loaded with 

 moisture, with the consequences already mentioned : 

 the nights are warmer, the days cooler, the winters less 

 severe, the summers less scorching. In qne word, the 

 climate is more equable. Moreover, the ocean is 

 warmer than the land, in winter and by night, while 

 it is cooler, in summer and by day ; and this tends to 

 further equalize the temperature. 



