COLD SOILS. WARM SOILS. COLOR. 89 



300. Soils iii which clay predominates are usually 

 heavy, stiff, wet and cold, and difficult to cultivate. But, 

 when well drained, amended by the application of sand 

 and of humus, and carefully tilled, they produce abun 

 dantly, and repay the pains and expense which have been 

 bestowed. 



Wet lands are cold because of the continual evapora 

 tion of the water at the surface. Every one knows that 

 when a wet hand or face is exposed to the wind, it feels 

 cool. As the moisture is converted into vapor, it takes 

 up heat, and gives to the surface a sensation of coolness. 

 In the same way evaporation renders the surface of a wet 

 soil constantly cool. 



801. But lands commonly dry are on that account 

 warm. Sandy land retains heat far better than clayey 

 or peaty land. 



Color also has an important influence. Dark-colored 

 soils absorb heat, while light colored soils readily reflect 

 it. Most manures arc dark-colored. Rich soils, there 

 fore, naturally absorb heat, and rich sandy soils retain it, 

 better than poor ones. 



That color has an effect upon the power of absorbing 

 heat is proved by Dr. Franklin s experiment. Place 

 black, blue, red and white pieces of cloth on the snow in 

 the sunshine, and, after some hours, the sun s heat will 

 have been so abundantly absorbed by the black, that it 

 will have sunk into the snow before the white has begun 

 to grow warm, while the red will be just beginning to 

 sink and the blue will have sunk almost as far as the 

 black. 



302. There are few places in this part of the country 

 where the soil has been formed by the crumbling of the 

 rocks just beneath the surface. In most parts of the 



