NO. 17.] 



WIND. 



305 



All directions are found. Among the weaker winds, East is most, and 

 West least frequent. Among the stronger winds, South-East is most, and 

 South-West least frequent. October, strongest ESE, weakest W, NW and N. 

 November, strongest E, weakest W. As will he seen further on, the dyna- 

 mic wind-roses for the dark season give as the strongest winds NNW and 

 SSE, and as the weakest wind E; for the sunny season, strongest wind E, 

 weakest SSW; and for the equinoctial months, strongest winds NE, weakest E. 



The frequency of the fresher winds has a diurnal period of a character 

 similar to that of the velocity of the wind in general, as will be seen from 

 the following Table. This Table gives the number of observed winds with 

 a velocity of 10 metres per second and upwards, reduced to bihourly daily 

 observations during the three years from September, 1893, to August, 1896. 



The minimum occurs at midnight, and the maximum at 6 p. m. The 



frequency of the winds with a velocity equal to, or above, 10 metres per second 



is below the mean, 35.6, during the night from 9 p. m. to 9 a. m., and 



above the mean during the day from 9 a. m. to 9 p. ni. PI. I (v^- 10 m. p. s. 



— 1 cm. = 100 cases. 



39 



