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which the plants are growing should be accordant 

 with that to which their leaves are exposed. When 

 we say accordant, we do not mean that the tempera- 

 tures should be equal, but that the heat of the soil 

 should stimulate the roots to imbibe nutriment just 

 so fast as the temperature and light of the air enables 

 the leaves to elaborate it. It is not difficult to find a 

 rule for the gardener's guide on this point, for after 

 numerous trials, both in this country and between the 

 tropics, we find a close approximation to the truth to 

 be, that the temperature of the soil ought to be just 

 above the average of the temperatures to which the 

 leaves of the plants growing upon it are subjected. 

 Thus, if the pine apple grows in air, of which the ex- 

 treme temperatures are 70 and 90 degs., the tempera- 

 ture of the soil in which they are rooted should be 8 1 

 or 82 degs. If the soil be heated solely by exposure 

 to the air of the stove, this accordance of temperature 

 is secured without trouble, but if there be a tank of 

 hot water, or a mass of fermenting matter beneath the 

 soil, great care is required, and great difficulties arise 

 in the way of regulating the soil's temperature. 



You may have the best of soil and water, but with- 

 out bottom heat is very particularly and punctually 

 attended to, great disappointments will ensue ; there 

 is more injury done by bottom heat than by all the 

 other causes put together ; and, in our opinion, this 

 was, in the first instance, the means of giving them 

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