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present a wanner climate beneath them than 

 groves of deciduous trees ; because the former, 

 from the closer texture of their exterior surface, 

 reflect back more completely the heat radiated 

 from the ground below. The more any plant is 

 shaded in winter, the less danger it will be in of 

 suffering from frost. For, when a plant, or water, 

 is so situated as to be overtopped by trees, the 

 radiation of caloric is in a great measure checked; 

 and thus in such situations, we may often observe 

 water unfrozen, arid plants unhurt by the cold, 

 and many retaining their leaves, when others of 

 the same species, at a short distance, but un- 

 shaded, lose their leaves and suifer considerably. 

 Mr. John Street, the gardener at Beil, who 

 has succeeded in acclimating numerous plants, 

 states, in the Transactions of the London Horti- 

 cultural Society, that he has found poor, dry arid 

 shallow soils and declivities, to be best adapted 

 for preserving plants through the winter season. 

 The quicker the superabundant fluid passes away 

 from the roots the better. From every observa- 

 tion, it appears that those plants which have the 

 least sap in winter, or the sap of which is of a 

 resinous or oily nature, suffer least from cold. 

 It would be foreign to my purpose to enter into 

 a discussion of the cause of this, or of the theories 

 that have been built upon it ; suffice it at present 

 to say, that it has been supposed that the prin- 

 cipal cause of the destruction of tender plants in 

 winter, is owing to the vessels being burst by the 

 freezing of the sap. In choosing plants, there- 



