ON THE METEOROLOGY OF IRELAND. 



333 



ELEMEMTS OF MONTHLY ISOTHERMAL LINES. 



We see then that, on the mean of the whole year, the isothermal 

 lines are inclined to the meridian by the angle N. 49 W. ; and 

 that the temperature increases in a direction perpendicular to these 

 lines, by -0112 of a degree for each geographical mile, or at the 

 rate of 1 degree for 89 miles. The increase of temperature, in 

 proceeding from north to south, is V= '0085, or 1 in 118 geogra- 

 phical miles ; the corresponding increase, in proceeding from east 

 to west, is U = -0073, or 1 in 137 geographical miles. 



We learn further, that the mean annual isothermal lines furnish 

 a very inadequate representation of the progression of temperature ; 

 and that when we follow the course of these lines from month to 

 month, we find them to vary within very wide limits. The extreme 

 positions of -these lines, as given in the preceding Table, are those 

 for the months of June and November. But the result obtained 

 for the latter month must, I think, be regarded as anomalous, on 

 account of the irregularity in the distribution of temperature already 



