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THE CLIMATE OF IRELAND, AND 



In dealing with the subject of Climate, even in the cursory 

 manner which alone is suited to a discourse such as this, it is 

 impossible to overlook its effects upon animal and vegetable life ; 

 and therefore, although no physiologist myself, I will offer no 

 apology for laying before you some broad facts connected with 

 the sciences of life, in relation to Meteorology. 



To begin with the vegetable kingdom it is well known that 

 plants are dependent, in a remarkable degree, upon every change 

 of heat and moisture ; and that, accordingly, the genera and species 

 of plants are distributed on the earth's surface so that each shall 

 receive its proper supply. The distribution of temperature being 

 much more regular than that of moisture, the general features of 

 the geography of plants are determined by the former ; and thus 

 the several divisions of the vegetable kingdom are found disposed 

 in broad bands on the earth's surface, which are closely connected 

 with the isothermal lines. And the succession of these bands is 

 similar but of course more rapid, and therefore more readily 

 seen on the flanks of high mountains. Thus we meet, near the 

 base of the Andes, first the palms ; and then the tree-ferns. At 

 greater altitudes there, or at lower heights in the temperate re- 

 gions, we come to the deciduous trees among which the oak, the 

 beech, and the birch, are the principal. Then, as we ascend, we 

 reach the pines ; next the rhododendrons, and other dwarf shrubs ; 

 after these, at still higher elevations, the creeping herbaceous 

 plants ; and, lastly, at the very limit of vegetation, the lichens. 



But in studying the effects of temperature upon vegetable life, 

 it is important to observe, there are two pairs of limiting tempera- 

 tures to be considered, one wider, and the other narrower. The 

 former are the limits beyond which the existence and continued 



