6 22 Proceedings of the Royal Irish Academy. 



The numbers in Table XIII referring to Markree and Valencia are taken 

 from the Appendix III to the Weekly Weather Eeport. The last row of 

 figures are obtained from an analysis of the Weather Journals of Clare 

 Island Lighthouse for a period of eight years, 1903-1910. The number of 

 instances was taken for each month in which the observer, at 8 a.m., noon, 

 and 4p.m., recorded (b) "blue sky" with or without hazy atmosphere or 

 detached clouds. The totals for each month for the eight years were taken as 

 a percentage of the total possible number of observations. The numbers thus 

 found are given in the table. They may be taken as approximate values for 

 what might be called " fine day " conditions. The monthly variation is 

 fairly comparable with that of the duration of bright sunshine at Markree 

 and Valencia ; but it must be clearly recognized that the duration or occurrence 

 of blue sky is quite distinct from that of "bright sunshine" — i.e. sunshine 

 sufficient to leave its mark on a sunshine recorder. The maximum number 

 of " fine days " is found in June. This result does not necessarily lead us to 

 conclude that for Clare Island June is sunnier than May; but it may be 

 compared with the results already quoted for Falmouth and St. Anne's 

 Head. 



