6 16 



Proceedings of the Royal Irish Academy. 



In June, 1910, rain-gauges were fitted up at three places on Clare Island, 

 viz. at the lighthouse, in charge of the lightkeeper, Mr. P. Duffy, at the 

 Abbey, in charge of Mr. A. M'Greal, and near the hotel in charge of Mr. J. J. 

 M'Cabe, who also attended to a recording rain-gauge. The gauges which 

 were lent from the Eoyal College of Science for Ireland, by kind permission of 

 the Department of Agriculture and Technical Instruction, had unfortunately 

 to be removed after two years. The returns for the year 1911 were, however, 

 very complete and of particular significance for the fact that over that part of 

 Ireland the rainfall in 1911 was very nearly normal. In support of this 

 view we find that the Blacksod total for 1911 was 49 - 36 inches, which closely 

 agrees with the mean annual rainfall (1871-1905). The 1911 total for 

 Westport was 46 - 67, the mean annual being 46 - 20. At Markree Castle (&>. 

 Sligo) and at Cong the figures for 1911 differ by less than one per cent, from 

 the mean annual values. 



The following table furnishes some important data as to the annual 

 averages and space-distribution of rainfall over the district under considera- 

 tion : — 



Table X. 





Mean 

 Annual 

 Rainfall. 



Average 

 Number of 

 Rain-days 

 per year. 



1911. 



Station. 



Rainfall. Rain-days. 



Blacksod Point, 



Markree Castle, 



Valencia, 



Weslport, 



Dugort, 



Crossmolina, 



Clare Island Hotel. 

 ,, ,, Abbey, 

 ,, ,, Lighthouse. 



48-93 

 4 201 

 56-45 

 46-20 



52-87 



263 49-36 186 

 248 — — 

 248 — 



— 46-67 200 

 67-89 213 



47-74 217 

 49-98 226 



— 43-02 170 (?) 



1 



The numbers in the above table must be studied with due consideration 

 of the limited accuracy of all rainfall observations, and of the numerous 

 sources of error, personal and otherwise. The values for Clare Island 

 lighthouse are undoubtedly too low. Small falls were frequently ignored ; 

 and the daily returns in other cases were very much at variance with the 

 indications of the self-recording gauge at the hotel. It seems safe and 



