THE AMERICAN BOTANIST 



27 



seems obvious that we have found a strictly scientific basis for 

 the classification of plants and animals." 



Rainfall Due to Forests. — Much has been written for 

 and against the theory that forests affect the rainfall without 

 any very definite conclusions having been reached. Instances 

 are on record where the removal of the forests have caused the 

 gradual drying up of a region, but this was ascribed to the 

 accepted fact that forests retard the evaporation and run-off 

 and their removal naturally affects the moisture. Whether 

 they increase the precipitation is entirely another matter, and 

 one that has never been definitely settled, though opinion seems 

 pretty much against it. Long continued experiments in 

 France, however, show that the average rainfall over a forest 

 compared to that over adjacent fields is as 100 to 76. If fur- 

 ther proofs of this nature are fo'und, we shall have to modify 

 our ideas as to the relation of forests and rainfall. There is 

 still another and seldom considered way in which trees affect 

 precipitation, namely by the condensation of fog and dew. In 

 foggy weather the condensation is quite noticeable, but even 

 when it is clear, more or less dew forms on trees and though 

 the deposit for a single night may measure the merest fraction 

 of an inch, in the course of a year it forms a considerable 

 amount. Estimates based on the amount of dew deposited on 

 a certain number O'f leaves in one night would indicate that 

 the annual dewfall may be equal to a rainfall of nearly 30 

 inches — more than many agricultural regions receive in an 

 entire year. 



Migrations of the Bobolink. — The bobolink, being a 

 lover of damp meadows, has for many thousands of years 

 been shut off from our Pacific States by the barrier of the 

 arid lands. At the present time, however, the progress of irri- 

 gation has established throughout the region fertile spots by 

 way of which the birds can cross. Small colonies, therefore, 

 are beginning to nest each summer on the western side of the 



