102 



diminished rainfall, because sufficient data are not yet available to 

 settle the question as to whether or not there can be fairly said to be 

 any decrease in the quantity of water delivered from the sky even 

 in recent years. In fact there are places in which we know that dur- 

 ing twenty years past the later decade has yielded as much rainfall as 

 the earlier one. Or, if we include in our estimate a term of years 

 measured by centuries and raise the question as to whether or not we 

 are undergoing a cyclic period of drought as compared with earlier 

 periods, then we are simply invoking an hypothesis which itself re- 

 quires defence. 



It, of course, would explain the present diminished flow if we could 

 prove a diminished fall extending through a long term of years, but 

 in seeking and offering such an explanation we are assuming as true 

 that which requires to be proved. The term "cyclic change" is eu- 

 phonious and seductive, but as a matter of fact we know as little about 

 cyclic changes as we do about almost any terrestrial condition. In 

 reasoning with them for a basis we argue not upon what we know, but 

 upon what we do not know. 



Apropos of this we may quote from Bulletin D, United States DQ- 

 partment of Agriculture, page 18, "Rainfall of the United States," by 

 Alfred J. Henry, Chief of Division: "It is true that suggestions of a 

 faint periodicity have been found in some regions of the globe, but it is 

 still the general belief that the vicissitudes of rainfall, if not wholly 

 fortuitous, are so intermingled with the variations ot pressure, tem- 

 perature, etc., that no satisfactory solution of the problem will be 

 reached until the greater problem of the general circulation of the at- 

 mosphere has been solved." 



In the Monthly Weather Review for September, 1897, page 395, Prof. 

 H. A. Hazen has gathered together the scattered data which seems to 

 prove more clearly than ever before that the removal of our forests has 

 not appreciably diminished our rainfall 1. c. p. 397, he says: "Ob- 

 servations of this nature, condensation in or over a forest, however, 

 can not ordinarily be checked by instrumental means, but show in a 

 general way that the forest tends to conserve vapor and moisture, 

 which, in the case of the open field, would be diffused into the atmos- 

 phere." 



There would remain then, the assumption that this diminished flow 

 comes from some change, or changes, made in the hitherto established 

 balance of nature. Of such possible changes the one most frequently 

 invoked is the removal of the forests. These are some of the facts 

 which appear to bear upon the case : 



1st. It seems to be proven tliai I here is a diminution in the volume 

 carried in our streams during Ihe dry season, and Ilia! this is marked 

 over wide areas. 



2d. It is certain that our woodland areas in which water is hoarded 

 are decreasing, and that in the same measure our areas of rapid evapo- 



