242 



WEATHER AND CLIMATE 



much more rapidly cannot be stated with certainty, because 

 soils differ greatly from one another. The darker or the 

 coarser the soils, the more rapidly they absorb heat. 



There is another very important difference between the 

 heating of land and of water by the sun. The rays of the 



sun penetrate to a 

 greater depth in 

 water especially 

 clear water than 

 in soil. In addition 

 to this, the water is 

 constantly in motion 

 and is communicat- 

 ing the heat from 

 the surface to the 

 cooler waters below. 

 Thus the summer's 

 heat affects the water 

 many feet below the 

 surface. This makes 

 a lake or sea a veri- 

 table storage tank 

 for summer's heat, 

 yet the distribution 

 of heat keeps the 

 surface waters rela- 

 tively cool in sum- 

 mer. 



The land, on the other hand, receives all of the sun's 

 heat upon its surface. The top few inches of soil heat up 

 very rapidly every summer's day, but soil immediately 

 below this shallow crust never becomes very warm, and 



PALM TREES ON TROPICAL ISLAND OF 

 TAHITI 



There is almost no range in the temperature 

 of this island throughout the year. 



