IMPORTANT QUESTIONS RELATIVE TO IRRIGABLE LANDS. 91 
in a slight degree the general results. But the operations of man on the 
surface of the earth are so trivial that the conditions which they produce 
are of minute effect, and in presence of the grand effects of nature escape 
discernment. Thus the alleged causes for the increase of rainfall fail., The 
rain gauge records of the country have been made but for a brief period, 
and the stations have been widely scattered, so that no very definite con- 
clusions can be drawn from them, but so far as they are of value they fail 
to show any increase. But if it be true that increase of the water supply 
is due to increase in precipitation, as many have supposed, the faet is not 
cheering to the agriculturist of the Arid Region. The permanent changes 
of nature are secular; any great sudden change is ephemeral, and usually 
such changes go in cycles, and the opposite or compensating conditions 
may reasonably be anticipated. 
For the reasons so briefly stated, the question of the origin and perma- 
nence of the increase of the water supply is one of prime importance to 
the people of the country. If it is due to a temporary increase of rainfall, 
or any briefly cyclic cause, we shall have to expect a speedy return to 
extreme aridity, in which case a large portion of the agricultural industries 
of the country now growing up would be destroyed. 
The increase is abundantly proved; it is a matter of universal expe- 
rience. ‘The observations of the writer thereon have been widely extended. 
Having examined as far as possible all the facts seeming to bear on the 
subject, the theory of the increase of rainfall was rejected, and another 
explanation more flattering to the future of agriculture accepted. 
The amount of water flowing in the streams is but a very small part 
of that which falls from the heavens. The greater part of the rainfall 
evaporates from the surfaces which immediately receive it. The exceed- 
ingly dry atmosphere quickly reabsorbs the moisture occasionally thrown 
down by a conjunction of favoring conditions. Any changes in the sur- 
faces which receive the precipitation favorable to the rapid gathering of the 
rain into rills and brooks and creeks, while taking to the streams but a 
small amount of that precipitated, will greatly increase the volume of the 
streams themselves, because the water in the streams bears so small a pro- 
portion to the amount discharged from the clouds. The artificial changes 
