The Corvallis gazette. [volume] (Corvallis, Or.) 1862-1899, 1891-06-26

and formation of such chasms, and
substituting in their place very small
ones. This process of diminishing the
capillary tubes is continued until the
whole depth of the soil attains pow
dered condition not only rendering
land capable of being cultivated at
nearly any time of the year, but also
during the warm season preventing
the rapidity of the evaporation OF
moisture. 2. The temperature of the
soil is raised. This is brought about
by allowing the air to enter and ira
verse among the particles of soil.
Well drained land may be saturated
for time after a heavy fall Of rain 80
that all the passages are filled with
} water, but as this descends it is re-
placed by air, for where water finds a
channel air can always follow, and
warm air as in summer, circulating
through the soil likewise gives off it's
heat. The temperature of undrained
land is more uniform than that OF
drained, being nearly the same winter
and summer, and corresponds to the
mean annual temperature of the air
in that locality. Besides the amount
of heat obtained by circulating air, d
much greater quantity, that required
for evaporating water or changing
liquid water into vapor of water, is re-
tanned. The effect of cooling can be
strikingly illustrated by allowing a
few drops of alcohol, or, better still,
ether, to evaporate on the hand, when
a decided sensation of cold is eXper-
fenced. The same change takes place
in wet soil although in smaller de-
gree, water evaporating less rapidly.
Parkes has given illustrations of the
cooling effects of evaporation. Sup
pose, he says, that the yearly rainfall
is thirty inches, this would amount to
10S, 900 cubic feet, or 303S tons to the
acre, per annum, or 298 cubic feet per
diem, 4. e., to 81s tons or IS, ,647 pounds
for each day in the year. To evapo
rate such an amount of water, 2400
pounds of coal a day as ordinarily
used under steam boilers, would be
needed, or 100 pounds per hour per
acre throughout the year. AS the
specific heat, or power of obsorbing
heat of water, is greater than that of
any other substance, whether solid or
liquid, very much more heat is re-
quired in order to warm a given
weight of water than would be needed
to warm similar weight of soil, so
that the arge amount of water which
drains away from the land through
the pipes must represent an amount
of heat equal to that which would
have been consumed in effecting the
evaporation. Certainly water gives
the same amount of heat that it ab-
serbs, but so far as agricultural soils
are concerned, this does not help mat
ters much, as only plants of little val
ue do we'll with ground in an over sat
urated condition. The heat of sum-
mer and the cold of winter effect it but
little way below the surface. Drain
ed land, on the contrary, is more ac-
cessible to the extremes of tempera-
ture, so that the temperature of that
soil corresponds with that of the air,
or nearly SO, throughout the respec-
tive seasons. This is an important
matter, for however warm and genial
the atmosphere may be for vegeta-
ton, plants cannot do well if the soil
into which their roots penetrate is
much colder than the air. 1t aids in
the prevention of draught. At first
thought this seems paradoxical. If
land can be drained Of surplus water
in wet season, why cannot this dry
ing action go to much greater eX-
tent in a dry one? Let us illustrate.
IF in summertime we fill glass with
cold water we perceive after a short
length of time that thin film of mois-
ture has collected on the outside Of
the glass. This water came from the
atmosphere formed by contact Of the
warm air with the cold sides of the
glass, and on this same principle are
plants supplied with moisturein drain
ed lands during dry seasons. The
warm air circulates among the cool
particles of the soil and is condensed;
the principle being the same as that
by which we receive water when steam
is allowed to enter a condenser the
worm of which is surrounded by
colder medium. By this means are
plants supplied with water from the
atm OSpere