of 



by a twenty-five-mile wind as from a place in 

 the dead calm of the forest. The quantity of 

 water evaporated within a forest or in its shelter 

 is many times less than is evaporated from the 

 soil in an exposed situation. This shelter and 

 the consequent decreased evaporation may save 

 a crop in a dry season. During seasons of scanty 

 rainfall the crops often fail, probably not be- 

 cause sufficient water has not fallen, but because 

 the thirsty winds have drawn from the soil so 

 much moisture that the water-table in the soil 

 is lowered below the reach of the roots of the 

 growing plants. 



In the arid West the extra-dry winds are in- 

 satiable. In many localities their annual capa- 

 city to absorb water is greater than the annual 

 precipitation of water. In "dry-farming" local- 

 ities, the central idea is to save all the water 

 that Nature supplies, to prevent the moisture 

 from evaporating, to protect it from the robber 

 winds. Forests greatly check evaporation, and 

 Professor L. G. Carpenter, the celebrated irri- 

 gation engineer, says that forests are absolutely 

 necessary for the interests of irrigated agricul- 



127 



