DISCUSSION : FORESTS, RESERVOIRS, AND STREAM FLOW 473 
In short, it is true, as every one knows, that the almost universal mr. Chitten- 
belief among our people to-day, developed in large part through the den. 
agency of supposedly well-informed persons, is that forests do diminish 
flood heights, and the statement that they do not, comes to most people 
as a distinct surprise, and their first impulse 1s emphatically to dispute it. 
The position now taken in this matter by Messrs. Swain, Pinchot, 
and Leighton* involves a complete change of base, so far as the 
writer’s study of current literature, both official and non-official, upon 
this subject goes. Extreme high waters, it is now held, are not the 
important matter at all, but the average high waters of a period of 
years; and for this purpose a period of ten years has been found by 
the Geological Survey to be long enough. It is difficult to understand 
just what this means. Mr. Leighton says that by his method the floods 
are “smoothed out and compensated and afford a less involved idea”; 
and that “extreme conditions are mere sports, due to unusual occur- 
rences, and it is as illogical to consider them as representative of 
general tendencies, as it would be to accept the physiological and 
anatomical freaks in a museum as representative of the human race.” 
The same rule applies also to low waters. 
This is very ingenious, and may be entirely satisfactory to Mr. 
Leighton, but the writer would like to ask him if the idea would ever 
have found birth had river records been different than they are in 
the matter of high floods. Does any one doubt that, if the figures in 
Table 1 of the paper had shown a progressive increase of flood heights 
with the progress of deforestation, they would have been blazoned 
from one end of the country to the other as evidence of the baneful 
effects of deforestation? Now that they show no such tendency, but 
the reverse, if anything, this feature is pronounced to.be quite a sub- 
ordinate matter, and the main point is said to be the frequency of 
floods of ordinary height. It is not the great floods that come occa- 
sionally, but the lesser floods that come often, that should be con- 
sidered as of first importance. Mr. Leighton takes periods of years, 
obtains the means of the floods, smooths or flattens out the irregular- 
ities, pronounces these results to be the real criteria, and, by compar- 
ing similar periods in states of progressive deforestation, arrives at the 
conclusion that these smoothed-out results increase as the forests dis- 
appear. The great floods which have always come, no matter what the 
state of the forests, he curtly dismisses as “sports” or “freaks,” not 
subject to intelligent rule and not to be considered as affecting the 
merits of the question. 
Accepting Mr. Leighton’s tables as entirely correct (the writer has 
had no time to verify them) and accepting for the moment the cor- 
rectness of his conclusion, that the results shown are due to deforesta- 
* The writer frequently uses these three names conjointly because their discussions 
run so closely parallel as to amount practically to identical, or at least supplementary, 
statements. 
