80 ELEMENTARY FORESTRY. 
subject, I quote the following extract on forest influences from 
the report of the Forestry Division of the U. S. Department of 
Agriculture for 1889, with a few changes in the nature of abbre- 
viations: 
“The water capital of the earth may be regarded as consist- 
ing of two parts, the fixed capital and the circulating capital. 
The first is represented not only in the waters on the earth but 
also by that 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 in 
suspension and is never precipitated. 
“The circulating water capital is that part which is evap- 
orated from water surfaces, from the soil, from vegetation, and 
which, after having temporarily been held by the atmosphere in 
quantities locally varying according to the variations in tem- 
perature, is returned again to the earth by precipitation in the 
form of 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 evaporation. 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 reference to its practically 
unchanged total quantity. 
“As to the amount of this circulating water capital we have 
no knowledge; hardly an approximate estimate of the amount 
circulating in any given locality is possible with our present 
means Of measurement; for it appears that so unevenly is the 
precipitation distributed that two rain gauges almost side by 
side will indicate varying amounts, and much of the moisture 
which is condensed and precipitated in dews escapes our obser- 
vation, or at least our measurements, entirely. Thus it occurs 
that while the amount of water calculated to be discharged 
annually by the river Rhone into the sea appears to correspond 
to a rainfall of 44 inches, the records give only a precipitation 
over its watershed of 27.6 inches. 
