Mr. Willis.. 
Leighton. 
394 DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 
control of the waters in their circulation over and through the land 
must recognize that the forces of Nature, involved in rainfall and 
sunshine, in the quiet stream and in the great flood, can be regulated 
and brought to serve Man, but only through the co-operation of all 
the forces that he can bring to bear. The farmer who before long 
will cultivate more than one-half of our country, the herdsman who 
will graze his flocks over one-fourth, and the forester who, to supply 
our needs, must raise his crop of trees on one-fifth, must all co-operate 
to control the Genii of the waters. The opportunity to make them 
our servants is where we can turn them from the paths of the air 
or the channels of the rills to the dark courses underground in the 
recesses of the rocks. Every method of agriculture, grazing, and 
forestry must be used to promote ground storage and reduce run-off. 
Even then there will remain a certain surplus of flood waters, the 
immediate gathering of which cannot be prevented. These and all 
other waters that join in our rivers in their course from, the mountains 
to the sea, must be committed to the care of the engineer, whose duty 
it is to store, to divert, to regulate them, so that they shall be made 
to serve every purpose to which civilization can put them. 
M. O. Lzicuton, Assoc. M. Am. Soc. C. E.—This paper is so 
admirable a literary composition and so persuasive in its presentation 
that one is well-nigh beguiled into acceptance of the author’s pre- 
cepts. It is only after critical review and the application of funda- 
mental principles that one is prepared to appreciate how erroneous are 
the premises, how mistaken the deductions. Such a consideration 
reveals several points of peculiarity, which may be summarized as 
follows: 
1. A large number of the premises and observations on which the 
author’s conclusions are based are in error; 
2. Nearly all his difficulties with reference to the relation of 
forests to stream run-off would be solved if he had not misconceived 
certain fundamental principles; 
3. In the progress of his argument he presents contradictory 
views; 
4, He rejects many generally accepted ideas, because little or no 
evidence has been brought forward in their support, and then he 
substitutes concepts of his own without any accompanying demon- 
stration. 
An attempt will be made to reveal all these peculiarities in the 
following discussion. No effort will be made to treat them in 
categorical order, because such is not the prime purpose of this re- 
joinder. The points will be indicated incidentally in the discussion 
of the principles involved. 
At the very outset there is revealed a fundamental misconception 
which largely explains many of the adverse deductions in relation to 
