IV 



AEROLOGY. 



By WILLIAM R. BLAIR. 



The treatment of this subject in one paper must necessarily be 

 general An attempt will therefore be made to cover the ground 

 and indicate points of contact between aerological observation and 

 aeronautics, leaving argument and details of methods to a fuller 

 treatment of the subject which, it is hoped, may appear in the near 

 future. 



Fig. I. Percentage of winds from each of eight directions for the year at 



selected stations. 



Means of observations already reduced and compiled will be 

 used in the discussion, not with the idea that these means will fully 

 serve the aeronauts' purpose, but that they indicate standard condi- 

 tions which to some extent show what may be expected at any time 

 and place and should be in mind for comparison with the individual 



PROC. AMER. PHIL. SOC, VOL. LVI, N, JUNE l8, I917. 



189 



