12 



On Climate, fyc. 



point of water, ten months in the year ; and even in the two 

 months, July and August, which are the only exceptions, a 

 thermometer covered with wool will sometimes fall to *35°. 

 It is, however, only low vegetation upon the ground which 

 is exposed to the full rigour of this effect. In such a situa- 

 tion the air which is cooled by the process, lies upon the 

 surface of the plants, and from its weight cannot make its 

 escape ; but from the foliage of a tree or shrub, it glides off 

 and settles upon the ground. 



Any thing which obstructs the free aspect of the sky 

 arrests in proportion the progress of this refrigeration, and 

 the slightest covering of cloth or matting annihilates it 

 altogether. Trees trained upon a wall or paling, or plants 

 sown under their protection, are at once cut off from a large 

 portion of this evil ; and are still further protected, if within 

 a moderate distance of another opposing screen. The most 

 perfect combination for the growth of exotic fruits in the 

 open air would be a number of parallel walls within a short 

 distance of one another, facing the south-east quarter of the 

 heavens ; the spaces between each should be gravelled, except 

 a narrow border on each side, which should be kept free 

 from weeds and other short vegetables. On the southern 

 sides of these walls, Peaches, Nectarines, Figs, &c. might be 

 trained to advantage, and on their northern sides, many 

 hardier kinds of fruit would be very advantageously situated. 

 Tender exotic trees would thus derive all the benefit of the 

 early morning sun, w T hich would at the earliest moment dis- 

 sipate the greatest accumulation of cold which immediately 

 precedes its rise, and the injurious influence of nocturnal 

 radiation would be almost entirely prevented. Upon trees 



