By John Frederic Daniell, Esq, 15 



sheltered situation. Experience amply confirms these theo- 

 retical considerations. It is a very old remark, that the in- 

 jurious effects of cold occur chiefly in hollow places, and that 

 frosts are less severe upon hills than in neighbouring plains. 

 It is consistent with my own observations that the leaves of 

 the Vine, the Walnut-tree, and the succulent shoots of 

 Dahlias and Potatoes, are often destroyed by frost in sheltered 

 valleys, on nights when they are perfectly untouched upon the 

 surrounding eminences ; and I have seen a difference of 30 

 degrees on the same night between two thermometers placed 

 in the two situations, in favour of the latter. 



The* advantages of placing a garden upon a gentle slope 

 must be hence very apparent : a running stream at its foot 

 would secure the further benefit of a contiguous surface, not 

 liable to refrigeration, and would prevent any injurious stag- 

 nation of the air. Few situations are likely to fulfill all the 

 conditions which theory would suggest for the most perfect 

 mitigation of the climate in the open air ; but the preceding 

 remarks may not be without their use in pointing out loca- 

 lities, which, with this view, are most to be avoided. 



Little is in the power of the Horticulturist to effect in the 

 way of exalting the powers of the climate in the open air ; 

 except by choice of situation with regard to the sun and the 

 concentration of its rays upon walls and other screens. The 

 natural reverberation from these and the subjacent soil, is 

 however very effective, and few of the productions of the 

 tropical regions are exposed to a greater heat than a well 

 trained tree upon a wall in summer. Indeed it would appear 

 from experiment, that the power of radiation from the sun, 

 like that of radiation from the earth, increases with the dis- 



