FORESTS IN THEIR RELATION TO RAINFALL. 237 



capital, and the circulating capital. The first is represented not 

 only in the waters on the earth, but also by the amount of water 

 which remains suspended in the atmosphere, being part of the 

 original atmospheric water masses which, after the rest had fallen 

 to the cooled earth, remained suspended and is never precipitated. 

 The circulating water capital is that part which is evaporated 

 from water surfaces, from the soil, from vegetation, and which, 

 after being temporarily held by the atmosphere in quantities 

 locally varying according to the variations in temperature, is 

 returned again to the earth by precipitation in rain, snow, and 

 dew. There it is evaporated again, either immediately or after 

 having percolated through the soil and been retained for a shorter 

 or longer time before being returned to the surface, or, without 

 such percolation, it runs through open channels to the rivers and 

 seas, continually returning in part into the atmosphere by evapor- 

 ation. Practically, then, the total amount of water capital remains 

 constant; only one part of it — the circulating capital — changes in 

 varying quantities its location, and is of interest to us more with 

 reference to its local distribution and the channels by which it 

 becomes available for human use and vegetation than with refer- 

 ence to its practically unchanged total quantity." 



c. To prevent evaporation of water. — In the Journal of 

 the Royal Agricultural Society, N.S., Vol. n., page 110, 

 there is a statement, by Mr. R. Orlebar, of Wellingborough, 

 on the advantage of planting trees around ponds, in which 

 he says, — 



"It is astonishing what effect a little shade has in checking 

 evaporation. A pond that is well shaded will hold water for 

 weeks after one of equal dimensions, but lacking shade, will 

 become dry." 1 



This is a matter of considerable importance to us as in 

 most parts of the country the conservation of water is 

 the first consideration. Officers having control of roads 



1 Brown, op. cit , page 55. 



