14 ON THE ANNUAL AND DIURNAL DISTRIBUTION OF THE 



the average in each separate month. "Winds from E.N.E. and E. are 

 above the average on the whole year as well as in each separate month 

 but December, January, February, and August. 



The north wind is above the average of all winds on the whole year, 

 and is above the average in some months and below it in others, but 

 without any perceptible annual period. 



The duration of the south wind is below the average of all winds, 

 taking the whole year collectively, as well as in each separate month 

 but May, June, July and August. 



The wind of maximum duration for the whole year collectively is 

 N.N.W. and the wind of minimum duration S.E. with a second maxi- 

 mum at east and a second minimum at N.N.E. 



The principal maximum is found at some point between W.S.W. and 

 N.N.W. in seven months ; but in April, May and June east winds are 

 the most frequent, and in July and September the most frequent wind 

 is from S.S.W. 



The wind of least duration is from S.E., S.S.E. or south in seven 

 months ; but in May, July, August, and September,* the least fre- 

 quent wind is from W.S.W., and in June it is from N.N.E. 



In table VII. the durations of the same wind in the different months 

 are compared. As the months are of different lengths, instead of com- 

 paring the absolute durations, which for the longer months would be 

 unduly great, this table is obtained by expressing the numbers of table 

 VI. in terms of the annual arithmetic means for the several winds. 



The change in duration from month to month exhibited by this 

 table is very irregular, excepting in the case of the south wind, which 

 decreases in duration continuously from its maximum in June to its 

 minimum in December, the maximum being to the minimum nearly 

 in the ratio of 8 to 1. 



If Ng be taken to denote the ratio which the duration of winds from 

 the three points N.N.W., north and N.N.E. in the six winter months 

 (October to March) bears to the duration of the winds from the same 

 three points in the summer half year, and if N7 be the corresponding 

 ratio when the winds from north are associated with those from the 

 three points on either side of it from W.N.W. to E.N.E., the ratios 

 for the analogous combinations about the three other cardinal points 

 being represented by Sg, S7, Es, E7, Wg, W7 ; it is found that 



• In September, the duration of the wind from E.S.E. is the same as that from W.S.W, 



