43 



The necessity of applying water, of a temperature 

 equal to that of the soil, is rendered evident by a refer- 

 ence to the natural conditions by which the soil is wa- 

 tered. In a small and nearly globular form, the water 

 gathered up by the action of the sun, and forming the 

 clouds above us, is precipitated through the atmosphere, 

 and there its temperature becomes equalized or assimi- 

 lated with that of the medium through which it has been 

 passing; and although in our own latitude, we perhaps 

 fail to discover any material degree of warmth in the 

 drops of rain as they fall, yet in eastern climes, we can- 

 not but imagine, that after having been submitted in the 

 thin strata of the clouds to the action of the sun, they 

 must previously to entering the soil, have imbibed some 

 portion of heat. Moreover, the importance of maintain- 

 ing a gentle bottom heat, at the roots of forced plants, 

 renders it necessary to avoid any application, which may 

 tend to lesson its effect, and submit the roots to any 

 chilling influence. The temperature of the soil is natur- 

 ally above that of the atmosphere, and as the application 

 of moisture by exciting evaporation, has an abstract ten- 

 dency to lower the temperature, it should therefore, 

 when applied, be in a slight degree warmed, so as thus 

 to increase rather than diminish the heat contained in 

 the soil. 



As some moisture in the soil is necessary to render 

 the food contained therein, soluble, and available to the 

 spongioles of the roots, so moisture in the atmosphere 

 is essentially necessary to assist in applying the gaseous 

 elements of that elastic compound fluid, to the nutrition 

 of plants by the action of the leaves : without moisture 

 in the atmosphere, the leaves and outer covering of plants 

 would become dessicated, and the stomatas shrivelled up 

 and closed, so that neither the exhaling nor the im- 

 bibing functions of the plants could then be carried on. 



