38 
THE TEMPERATURE OP PLANTS, AND OF THE GROUND. 
In England the amateur complains of his losses in February, before the drying winds 
of March come on. Our country is damp, and air cannot be admitted into pits and 
frames during haze and soaking mists ; and it is an undoubted fact, that cold dry air, even 
with several degrees of actual frost, does little injury even to succulent plants, provided 
they be so far defended as merely to guard against the destruction of their cellular tissue. 
The attempt to ascertain the internal temperature of trees or shrubs at any time of 
the year, must be attended with great difficulty ; its results also, will be, at best, uncertain 
and ambiguous. At all events, so long as the vital principle shall remain intact, the 
plant will be secure. The temperature of the ground, however, must be brought under 
consideration, inasmuch as it cannot fail to perform an important role in the mutual 
intercourse that exists between the fluids of the plant, and those of the medium in which 
its roots are established. The vast influence of electro-magnetism, also, should not be 
overlooked in conjunction with the heat developed by the disturbance induced during the 
decomposition of moist vegetable substances. Solar power, so far as light and heat are 
concerned, acts directly upon exposed surfaces, and the effects of both the rays are 
determinable by the senses, but they cannot penetrate to any great depth : to Electricity, 
that all-pervading, everywhere present agent, we must refer those chemical analyses which 
are induced far below the common surface. Chemical energy indicates the presence of 
Electricity ; they appear to act reciprocally. Vitality is directly opposed to the decom- 
posing power of either ; but from the moment that the vital principle is extinguished, the 
electro-chemical forces come into play, and the results which follow are the progressive 
development of what are erroneously called the elements of the defunct organic body. 
In the case of vegetables these pseudo-elements comprise three — sometimes four — gaseous 
aerial fluids, familiarly known as oxygen, hydrogen, carbonic acid, and perhaps nitrogen ; 
terms, which it will be an object to render intelligible in future communications. 
Whatever uncertainty may exist as to the actuating causes of variation in the tempe- 
rature of living plants, there can be none concerning the deteriorating effects of stagnant 
and superfluous water in the land. These and their causes are traceable, and thus we 
arrive at unerring conclusions on the importance of thorough draining. 
" If," observed Mr. Parkes, in his valuable paper, at page 119, et. seq., vol. v. of the 
Royal Agricultural Journal." — " If a soil be saturated with water the noblest classes of 
plants cannot flourish ; they vegetate more or less imperfectly, until the quantity of water 
be so diminished as to suit their habits. The reduction of the excess to the due pro- 
portion can only be efi'ected naturally, by its gradual evaporation, i.e. by its conversion to 
vapour ; and this transition would require the absorption of a quantity of heat, so 
enormous, as to startle any one who has only taken a superficial glance at the process of 
vaporisation." 
To convert a quantity of water, say one pound, to steam — would require about six times 
as much heat as would raise its temperature from 50° to 212°, that is, to the ordinary boiling 
point. But steam passing from open vessels can never be made to exhibit a higher 
degree of heat than that of the boiling water from which it exhales. How then can it 
be made to appear that, intrinsically, it contains more heat than the boiling water from 
which it escapes? The question can be solved by three processes. The first and 
simplest is that of condensation, whereby the steam from water boiled in a common still 
produces distilled water — a pure liquid, of very great value to the practical chemist. By 
it also, we obtain a convincing proof that a very small quantity of fluid can be condensed 
from a volume of steam many hundred times greater than that of the water operated 
upon, and reproduced in the receivers. Second, by passing the steam of boiling water 
into a given bulk of cold water, when it mil be found that one pound of steam will raise 
about six pounds of water from 50° to 212°. 
The converse experiment of dissolving one pound of pounded ice at 32^, in a known 
weight of boiling water, must prove eminently instructive, as it will show the immense 
quantity of heat that the ice will absorb. But why, or how should steam at 212° operate 
such marvellous effects? Is each individual particle the vehicle of six times its own 
apparent sensible heat ? Or is that agent, which, pro tempore, repels and keeps asunder 
