1898-1902. No. 4.] WIND -VELOCITY. ANNUAL PERIOD. 



WIND-VELOCITY. ANNUAL PERIOD. M. P. S. 



The smoothed numbers (Sm.) give an annual period with a chief 

 minimum of 3.31 m. p. s. in December, and a chief maximum of 

 4.30 m. p. s. in September. Range 0.99 m. p. s. There are secondary 

 minima in April and in July, and secondary maxima in March and in 

 June. The mean for the year is 3.67 m. p. s., corresponding to the 

 Beaufort Scale 2.6. 



Smoothing tlie weighted numbers for the mean monthly frequency 

 of Calms in the Table on pp. 230 & 231, we obtain the following figures, 

 showing the annual period of the frequency of Calms. 



March April May June 



38.2 36.3 31.6 27.8 per cent 



September October November December 



21.3 28.2 37.8 39.9 per cent 



Annual Mean 32.4 per cent 



Maximum December . . . 39.9 — 

 Minimum September . . . 21.3 — 



Range 18.6 — 



The annual period of the frequency of calms is very nearly the 

 inverse of the annual period for the velocity of the wind. 



