By John Frederic Daniell, Esq. 17 



It is well known that solar heat is absorbed by different 

 substances with various degrees of facility dependant upon 

 their colours, and that black is the most efficacious in this 

 respect. It has therefore been proposed to paint garden 

 walls of this colour; but no great benefit is likely to arise 

 from this suggestion. It is probable that in the spring, when 

 the trees are devoid of foliage, the wood may thus be forced 

 to throw out its blossom somewhat earlier than it otherwise 

 would; but this would be rather a disadvantage, as the 

 flower would become exposed to the vicissitudes of an early 

 spring. It is more desirable to check than to force this de- 

 licate and important process of vegetation, as much injury 

 may arise from its premature developement. When the tree 

 has put forth its foliage, the colour of its protecting support 

 can have no influence in any way : the leaves cover the sur- 

 face and absorb the rays by their own inherent powers. The 

 only known advantage which can be taken of this peculiar 

 power in dark substances, is in the case of covering up fruits, 

 to preserve them from the ravages of flies ; grapes which are 

 enclosed in bags of black crape ripen better than those in 

 white ; but I believe that it is admitted that neither do so 

 well as those which are freely exposed. 



I come now to the consideration of a confined atmosphere ; 

 the management of which, being entirely dependent upon 

 art, requires in the Horticulturist a more extended acquain- 

 tance with the laws of nature, with regard to climate, and 

 greater skill and experience in the application of his means. 

 The plants which require this protection are in the most 



vol. vi. D 



