Climate. 11 



of that important ingredient, than when they grow under a 

 shade. 



Nor ought the observation to be omitted, that darkness and 

 light have effects directly opposite upon vegetables. Dark- 

 ness favours the elongation of plants, by keeping up the pli- 

 ancy of their parts ; light consolidates them, and stops that 

 elongation, by favouring nutrition. Hence, in the northern- 

 most regions, where plants go through all their stages of growth, 

 at a time, when the sun no longer quits the horizon, the light 

 of which they thus experience the unremitting effect, hardens 

 them, before they have time to lengthen. Their growth is 

 there quick, but of short duration. They are robust, but un- 

 dersized ( I4 ). 



4. Moisture. The importance of moisture to vegetation 

 cannot be questioned. Water constitutes a large proportion 

 of every plant, and is the vehicle by which nutriment, in a 

 state of solution, is conveyed to plants. Hence, without so 

 essential an ingredient, they must either become stunted in 

 their growth, or perish. In dry weather, when vegetation 

 seems at a stand, no sooner do showers of rain fall, than a ra- 

 pid growth, of every kind of herbage, or of corn, immediately 

 succeeds. This takes place even on poor dry soils, where 

 otherwise, however well manured, vegetation would make but 

 slow progress ( l5 ). 



The quantity of rain that falls annually in any country, is 

 a very inferior consideration, when compared with that of 

 the general and equable distribution of that quantity, through- 

 out the several days and months of the year. A great abun- 

 dance, falling at the same time, is rather hurtful than bene- 

 ficial ; whereas those moderate, but golden showers^ which re- 

 gularly fall on a soil prepared to receive them, are real sources 

 of fertility. It is by this that the character of a climate, whe- 

 ther wet or dry, is chiefly determined, and the operations of 

 agriculture are principally influenced ( l6 ). 



The utility of moisture, with a view to vegetation, de- 

 pends much on the quality of the soil. The heavy rains 

 which prevail in the western districts of this Island, (vary- 

 ing from 40 to 60 inches in the course of a year), are in ge- 

 neral favourable to crops growing on sandy, gravelly, or 

 very dry land, but are injurious to the same crops, if pro- 

 duced on clayey or heavy soils. To bring grain crops to per- 

 fection, a certain portion of moisture is necessary, but weather 

 moderately dry, is most favourable to an abundant produce, 

 more especially of wheat, which is peculiarly liable, when in 

 blossom, to be injured by rain. An excess of moisture is pre- 



