THE CLIMATE OF IRELAND. 



39 



Hours of Bright Sunshine for 1901, and Average of 20 Years, with Percentage in each case. 



Badly drained land and retentive geological Formations have not only 

 P , ,. „ a cooling effect on the air in immediate contact with 



Kelations ot ,^,^^^^^^ ^^^^ through the diffusion of the chilliness have 



Air and Soil '^ material effect upon tlie island as a wliole. ihis is 



a subject which may well repay full consideration j 

 for the circumstances of cause and effect act and react. A damp atmos- 

 phere hinders the heating effects of the sun upon the land ; and damp cold 

 soils and rock Formations, on the other hand, cause dampness of the atmos- 

 phere. 



Prof. Seeley, F.R.S., classifies rocks and superficial deposits (sands, 

 gravels, etc.) as follows, according to the effects which they severally have 

 upon local climate* : — 



Pebble beds. Sands, and Sandstones ; dry, bracing atmosphere. 



Limestone ; though usually well-drained, is over- 



hung by steamy atmosphere in 

 summer. 



Clay Slates ; damp and cool atmosphere. 



Crystalline Rocks ; do. 



The extensive tracts of bog and alluvium in the centre of Ireland have a 

 lowering effect upon local temperature, and no doubt also have an effect 

 to some extent upon the general climate of the island. Reclamation of 

 moory soils, and even drainage of these and other water-logged surface 

 deposits, would tend to alleviate this disadvantage. Wollny proved by an 

 elaborate series of experiments carried out at Munich in 1890, 1892, and 

 1893, that top-dressing peat-soil, not to speak of the well-known advantage 

 of thorough draining, had the effect of raising its temperature, particularly 

 when the top-dressing was viingled with the uppermost layer of peat ; and 

 this both in upland moor soils {H ocJnnoorbodcn') and lowland {N iederungs- 

 moorbode'ii)^^ 



AERIAL CURRENTS. 



Many elements combine to produce variation in the direction and pressure 

 of winds in the Irish region. Amongst them, may be reckoned land and sea. 



* Sir J. W. Moore, " JMeteoroIogy, Practical and Applied," p. 35. 

 \ Forschungen a. d. Gcb. d. Agriculturphysik for 1894, pp. 245 et seq. 



