422 



The Rev. H. Lloyd on the Meteorology of Ireland. 



From the preceding Table we obtain the following corrections, which are to 

 be applied to the means of the observed temperatures at 9 a. m. and 9 p. m., in 

 order to reduce them to the mean of the day : — 



It hence appears that the correction is nearly constant throughout the sum- 

 mer, and throughout the winter months, respectively. The mean summer cor- 

 rection is + O^'l ; the mean winter correction + O^'G. 



Mean Monthly Temj?eraturcs. — The mean temperatures have been obtained, 

 at all but three of the stations, from the observations at 9 a. u. and 9 p. m., by 

 the application of the preceding corrections. At IMarkree the observations 

 were taken at 10a.m. and 10 p.m.; and the reducing mmibers are therefore 

 somewhat different, and smaller in amount. At Portarlingtou and Athy the 

 observations were taken but once in the day, namely, at 9 a. m. ; and at these 

 stations, accordingly, the mean temperatures are inferred from the maximum 

 and minimum temperatures as given by the self-registering thermometers. The 

 formula employed is that of KiEMTZ, viz. : — 



7nean temp. — min. + a (max. — niin.) 



The mean value of the coefficient,* as deduced from the observations at the 

 observatories of Armagh, Markree, and Dublin, is a=:0-41. 



The following Table contains the resulting values of the mean temperature 

 for the several months of the year 1851 : — 



* The coefficient in Kj;mtz's formula appears to vary considerably at different places, both in 

 its mean amount, and in the law of its variation from month to month. At Armagh and Markree 

 its greatest value is in December, and its least in July ; at Dublin, it is the reverse. I have taken 

 above the mean of the yearly values for the three stations. 



