CH. II.] THE ROOTS. 73 



surface, is always, during -vs-inter, some degrees 

 wanner than the exterior air ; but, owing to the 

 evaporation from the sides of garden pots, this 

 is rarely the case with the soil 

 in them. To presence this salu- 

 tary warmth to the roots, a double 

 pot has been suggested, as re- 

 presented in the accompanying 

 sketch. 



The importance of following the dictate of nature 

 to keep the roots of plants, natives of the torrid and 

 temperate zones, as warm or waimer than the 

 branches, has been too much neglected by the gar- 

 dener in his forcing department. In the vinery, for 

 example, the stem and roots are too often absurdly 

 exposed to the rigour of winter ; whilst the buds are 

 expanding within the glass shelter in a temperature 

 of 60°. A vine so treated, is like the felled elm, 

 which, allowed to retain its bark, though rootless, puts 

 forth its leaves in the spring ; expands its buds, and 

 advances through the first stages of growth merely 

 from the inspissated sap stored within its stem and 

 branches. This is no mere suggestion of fancy ; for 

 repeated experiments have showTi that hot-house 

 vines, with their roots thus kept torpid by exposure 

 to cold, had not their buds burst ; whilst other ^dnes, 

 treated in all respects similarly, but vdih their roots 

 kept genially warm, were actually in bloom. 



