THE PINE APPLE. 167 



sheat still better: and though the heat of the earth, 

 in its native country, may never exceed that of 

 the surrounding atmosphere, it does not follow that 

 earth heated to a greater degree may not be of ser- 

 vice to it, in a state of artificial culture. But ad- 

 mitting, for the sake of argument, that the Pine plant 

 could be grown equally well with, as without bottom 

 heat ; still it appears to us that the mass of material 

 which furnishes this heat, will always be a most de- 

 sirable thing to have in a Pine stove, as being a per- 

 petual fund of heat for supplying the atmosphere of 

 the house, in case of accident to the flues or steam 

 apparatus. Besides it appears from nature, as well 

 as from observing what takes place in culture, that 

 the want of a steady temperature and degree of 

 moisture at the roots of plants is more immediately 

 and powerfully injurious to them than atmospheric 

 Changes. Earth, especially if rendered porous and 

 spungelike by culture, receives and gives out air and 

 heat slowly ; and while the temperature of the air 

 of a country, or a hot-house, may vary twenty or 

 thirty degrees in the course of twenty-four hours, 

 the soil at the depth of two inches would hardly 

 be found to have varied one degree. With respect 

 to moisture, every cultivator knows, that in a pro- 

 perly constituted and regularly pulverized soil, what- 

 ever quantity of rain may fall on the surface, the 

 soil is never saturated with water, nor, in times of 

 great drought, burnt up with heat. The porous 

 texture of the soil and sub-soil being at once favour- 



M 4 



