14 



The importance of bottom heat in the culture of tender 

 plants, has always been well known by its practical effects. 

 The mean temperature of the soil, at a slight distance 

 below the surface, is universally above that of the 

 superincumbent air ; and consequently some degree of 

 bottom heat is always supplied to plants, in a state of 

 nature. Naturally, by means of subterraneous heat, and 

 also by the absorption of the sun's rays during the time 

 they are forcibly directed towards the earth, it possesses 

 the means whereby any material degree of cold at the 

 roots of plants is prevented ; and when the soil is acted 

 on by the unveiled sun of an eastern sky, we cannot but 

 feel certain, that even a considerable amount of heat must 

 be experienced : hence arises the importance of taking ad- 

 vantage of every ray of sun which our climate affords, 

 when the culture of the Cucumber, or of any native of 

 warmer latitudes, is attempted out of doors in this country ; 

 and also of using every possibly available means of increas- 

 ing rather than diminishing the temperature of the soil : 

 and hence too, in forcing not only the Cucumber, but also 

 every other plant which requires to be submitted to a con- 

 fined atmosphere, and an elevated temperature, arises the 

 necessity of providing such a degree of warmth at the root, 

 as may tend to keep its vital powers in a vigorous state of 

 action; it will effect this, by acting in conjunction with 

 moisture, as a solvent of the food which is primarily con- 

 tained in the soil in a solid form, but can only be taken up 

 by the capillary action of the spongioles of the roots, when 

 converted into a fluid state. The science of Chemistry has 

 taught us that the ingredients composing the soil, act on, 

 and dissolve, and combine with each other,, in various 

 ways, sometimes being simply dissolved and held in solu- 

 tion, and at other times, entering into new combinations, 

 and forming new compounds ; but in all cases, the natural 

 agents, heat and moisture, are necessary to produce these 

 results, and to present to the tender roots of plants, food 



