6 



Proceedings of the Royal Irish Academy. 



July, when they were equal) to have occurred more frequently by night than 

 by day ; but the difference was such as not to always appear in the small 

 numbers that expressed, as a percentage, the frequencies of such winds. 



A study of the changes in intensity between 12 noon and 12 midnight, 

 each day, gave the results expressed as percentages shown in Table V, 



Table V. 



!ases of Change of Intensity 



betv; 



zen 12 noon 



and 12 midnight. 











Percentage. 











\ 



- 



1 



January, 







25 



35 



40 



February, 







27 



31 



42 



March, 







29 



36 



35 



April, 







25 



39 



36 



May, 







31 



31 



38 



June, 







30 



40 



30 



July, 







25 



42 



33 



August, 







27 



39 



34 



September, 







31 



38 



31 



October, 







25 



38 



37 



Xorember, 







25 



37 



38 



December, 







26 



31 



43 







12) 



326 



437 



437 1200 



Annual, 







27 



37 



36 100 





1: 



Means /a/? ii 



intensity. 







t- 



>, 



rite 



» 







— 



,, 



no change in intensity. 



It will be seen that no change in intensity occurs, on an average, in about 

 37 per cent, of eases. The changes are, on the whole, more frequently in the 

 form of an increase in intensity towards night, especially in the winter 

 months, January, February, November, and December. 



The changes in direction of the wind in passing from noon to midnight 

 were studied next and are represented in Table VI. No change is recorded 

 in 50 per cent, of cases on an annual average, and of the changes, 

 28 per cent, are clockwise, and 22 per cent, anti-clockwise. A change in 

 direction occurs most frequently in February. March, and December. The 

 excess of clockwise changes over anti-clockwise changes is most marked in 

 January, February, and September. 



