10 /da 



Fig. 2. 



transport per second after W. Wereskiold's method(^). First the length 

 of the arrows for each wind rose has been measured by the percentage 

 scale. (Some few gross errors were, however, detected.) The next stage 

 is to get the forces reduced to velocities. We have used simple averages 

 of the limits of the velocities corresponding to each force, the tables 

 being as follows : 



The graphic tables by W. Wereskiold, which give the mean velocity 

 component in m./sec. in the N.-S. and the E.-W. directions were used 

 quite frequently. The resulting components in the N.-S. and the 

 E.-W. directions were found by simple addition and subtraction ; the 

 result is written down by two components (N. and E.) for each wind 

 rose. The magnitude of the mean resultant velocity (V) was calculated 

 by the formula 



V=v N^+E^ 

 and the direction of the mean resultant velocity (a) was determined by 



E 



the formula tan a = -., so the directions of N., E., S., and W. are given 



N 



by 0°,. 90°, 180°, and 270° respectively. 



(1) Geof. Publ., Vol. II, No. 9 (1922). 



106 



