THE FORCING POWER OF RAIN. 249 



blossoming of trees, in the flowering of primroses and 

 other spring plants, in rich growths of fungi, and in 

 various other ways. It cannot be doubted that there 

 is here a comparative waste of powers, which, expended 

 in due season, would have produced valuable results. 



The modern theories of the correlation of force 

 suffice to show how enormous a loss a country suffers 

 when there is a failure in the supply of rain, or when 

 that supply comes out of its due season. "When we 

 consider rain in connection with the causes to which 

 it is due, we begin to recognize the enormous amount 

 of power of which the ordinary rainfall of a country is 

 the representative; and we can well understand how 

 it is that u the clouds drop fatness on the earth." 



The sun's heat is, of course, the main agent we 

 may almost say the only agent in supplying the rain- 

 fall of a country. The process of evaporation carried 

 on over large portions of the ocean's surface is con- 

 tinually storing up enormous masses of water in the 

 form of invisible aqueous vapor, ready to be trans- 

 formed into cloud, then wafted for hundreds of miles 

 across seas and continents, to be finally precipitated 

 over this or that country, according to the conditions 

 which determine the downfall of rain. These processes 

 do not appear, at first sight, indicative of any very 

 great expenditure of force, yet, in reality, the force- 

 equivalent of the rain-supply of England alone for a 

 single year is something positively startling. It has 



