THE CULTIVATOR. 
375 
INFLUENCE OF WATER ON THE TEMPERA¬ 
TURE OF SOILS. 
It is well known that a really wet soil, as well as a 
very dry one, is unproductive. The various operations 
of an excess of water in checking vegetation, are not all, 
perhaps, easily told, but there is no doubt that one of the 
most important of its injurious effects, is the low tempe¬ 
rature which it induces in the soil. It is very common, 
when speaking of soils, to couple the term wet with cold , 
as such a soil is “ wet and cold.” Now the popular idea 
expressed in this case, is undoubtedly correct—that is, a 
wet soil, is of course a cold one. Several reasons why 
this is so, might be given; one of which is, that the de¬ 
gree of temperature which would otherwise communi¬ 
cate heat to the soil, produces evaporation, by which the 
heat is abstracted from the soil and dissipated in the air. 
There are other causes for the deleterious action of an 
excess of water in soils, but whatever they may be, it 
will be readily admitted that a removal of the evil by 
thorough draining, is expedient. In an essay by Josiah 
Parkes, published in the Journal of the Royal Agricultu¬ 
ral Society, we find the philosophy of this subject illus¬ 
trated in a manner more clear and satisfactory, than we 
have before met with. Mr. Parkes observes— 
“ As heat is generally considered to be an impondera¬ 
ble body, we are without the means of ascertaining di¬ 
rectly by weight or measure, the quantity of heat absorb¬ 
ed from soil by the evaporation of water. The follow¬ 
ing illustration of it will, however, be familiar enough to 
the mind of the engineer, and will also, I think, enable 
intelligent farmers to form an idea of its immense 
amount.” 
“ If we suppose the rain falling on the surface of an 
acre of land in a year to be 30 inches in perpendicular 
depth, it would amount to 108,900 cubic feet—3,038 tons; 
which, spread over a twelve-month, gives an average of 
298 cubic feet—8-| tons, or 18,647 lbs. per diem. This 
weight of water would require for its diurnal evaporation 
—supposing it were all carried off by that means—the 
combustion of 24 cwt. of coals, as ordinarily used under 
the steam boiler, or one cwt. per hour per acre, throughout 
the year! We thus obtain some idea of the abstraction 
of heat from land under the circumstances of perfect aque¬ 
ous repletion and stagnation, and there are too many soils 
approaching them. We may also imagine the depression 
of the terrestrial temperature consequent on the abstrac¬ 
tion of so much heat from the mass of the soil—a depres¬ 
sion which must ever be in proportion to the excess of 
water present in the soil, over and above the due comple¬ 
ment required for the supply of vegetation. Soils in that 
state must necessarily be very cold in the spring months, 
and much colder at the time of the commencement of ve¬ 
getation, and throughout the summer, than well drained 
or naturally drier lands. If we knew the capacity for 
heat of any given soil, and the weight of water mixed 
with it in excess, it would be easy to determine, very 
nearly, the depression of temperature caused by its eva¬ 
poration. We know that the heat of a pound of water in 
its gaseous state, that is steam,would keep down the tem¬ 
perature of 1,000 lbs. of earth one degree; of 500 lbs. two 
degrees, and so on.” 
“ Secondly, excess of humidity obstructs the absorp¬ 
tion of heat by the solid matter of the soil. Water in a 
quiescent state, is one of the worst conductors of heat with 
which we are acquainted. If it be warmed on the sur¬ 
face—and it derives, when mixed with soil, nearly all its 
heat from the sun's rays—water transmits little or no heat 
downwards.” 
“If a mass of water be heated from below, the whole 
quickly attains an uniform temperature by reason of mo¬ 
tion excited amongst its particles. The lowest stratum, 
when heated, becomes of less specific gravity than that 
resting upon it, and the heavier superincumbent portions 
descend and push that which has been warmed, upwards. 
Much of the heat of the sun’s rays, is, therefore prevent¬ 
ed by excess of*water from entering into, and being trans¬ 
mitted through, the mass of the soil.” 
“ Thirdly, water is a powerful radiator of heat, that is 
it cools quickly. All bodies, whether fluid or solid, pos¬ 
sess peculiar powers of emitting or radiating heat, and 
water is esteemed by the late Professor Leslie—in which 
opinion he has been joined by other philosophers—to 
stand at the head of radiating substances.” 
“ The phenomena of the production of cold by radia¬ 
tion and evaporation, are essentially exemplified by the 
well known experiment of exposing water, warm enough 
to give off visible vapor, in one saucer, and an equal 
bulk drawn from a well in another saucer. The former 
on a sharp frosty morning, will be found to exhibit soon 
est. Boiling water thrown on the ground, will freeze 
sooner than cold water. The cooling powers of evapo¬ 
ration and radiation combined, and if radiation chiefly, or 
solely, are represented in this experiment by the order 
of congelation in the two vessels in time; but the differ¬ 
ence in the quantity of heat omitted from each of them, 
is immense, as appears from wiiat is stated above with 
reference to the constituent heat of vapor.” 
“ Fourthly, as the temperature of water diminishes du¬ 
ring the night, or in the day time, according to the vary¬ 
ing conditions of the atmosphere, by radiating its heat to 
the heavens, its specific gravity increases; and the super¬ 
ficial stratum which is first cooled, immediately descends 
by reason of its augmented density. This film of cooled 
and heavier water is as quickly replaced by relatively 
warmer and lighter portions which become cooled in turn 
and successively sink. Water, therefore, though a non¬ 
conductor of heat downwards, when warmed on the sur¬ 
face, becomes a ready vehicle of cold in that direction, 
when cooled on the surface; and this cooling process may 
even continue, under fitting circumstances, until the 
whole of a given mass is reduced to the low temperature 
of 42 deg., at which point, water attains its maximum 
density. The further descent of cold through this pro¬ 
cess, would then cease; but the refrigeration occasioned 
by it must effect all soils, to a greater or less degree, 
which hold water in excess, that is, when in a state of 
stagnancy near to the surface. Those soils only can be 
exempt from this chilling influence which are not natu¬ 
rally retentive of water, or which are artificially and 
deeply drained. Thus excess of water conduces to the 
production of cold in soil by means of several independ¬ 
ent, vigorous, and ever active properties.” 
“ On the other hand, when a soil is naturally so po¬ 
rous, or is brought into such condition by art, that rain¬ 
water can sink down into the earth, it becomes a carrier, 
an alert purveyor, instead of a robber of heat; and tends 
to raise, permanently, the temperature of the mass of use¬ 
ful soil; and this more particularly and beneficially, du¬ 
ring the vegetative season. Rain-water, at that time, 
conveys downwards the more elevated superficial heat 
of the soil, and imparts it to the subsoil in its course to 
the drains; it leaves the soil in a fit state to receive fresh 
doses of rain, dew, and air, and in a better condition to 
absorb and retain heat, at the same time that it promotes, 
in other ways, its fertility and productiveness; but a con¬ 
sideration of the chemical effects attributable to the con¬ 
tinual circulation and renewal of water and air is foreign 
to the present discussion.” 
“ In order to render the change of water perfect, and 
its action uniform throughout a field, all drains should be 
deeper than the active or worked soil, and covered. Su¬ 
perficial drainage is comparatively of little value. If 
drains are open, much of the rain precipitated on the sur¬ 
face necessarily passes into them before it has permeated 
the whole mass; consequently it carries off with it heat, 
which would have been usefully employed in warming 
the lower strata. If drains are not deeper than the work¬ 
ed bed, water remains before in a staghant state, which 
must chill the roots of plants and diminish the tempera¬ 
ture of the superincumbent mass.” 
Crops in Illinois. —Extract of a letter from H. A. 
Cyrus, Esq. dated Houston, Oct. 17 —“In Adams coun¬ 
ty, the past season, the crops have been, of wheat, about 
an average; oats, good; corn and potatoes, poor, say 
two-thirds of an ordinary crop; these last, in part of this 
and the adjoining counties, are very inferior—had well 
nigh proved a failure; but in other places are very fine. 
It has snowed more or less, for three days past, and the 
ground is now covered from 3 to 4 inches. This is art 
early start for winter, in middle Illinois.” 
