The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1909-08-25

iSS capacity IOT retaining the WarnllH
derived from below is increased; and
this Is Of considerable value in early
planting.
Second-Let us consider the i'm
pOrtance Of dew to the growing crop.
When air containing moisture comes
in contact with an object cooler than
itself 1t deposits part of it's mois-
ture upon the object in the form Of
dew. In grick house where the
plaster is laid directly upon the brick
walls, In winter. while warm mois-
ture laden wind is blowing, follow
ing a cold spell. the water is condens-
ed upon the surface Of the cooler
walls. and trickles down in quantity
greater or less according as the diff
ference between the temperature Of
the air and that of the walls is greater
or less. and depending also. upon the
amount Of moisture carried In the
air. Now, during the growing season
the warm moist air in the same man
ner deposits its moisture upon the
cooler blades and leaves of plants,
and also upon and in the soil, though
the moisture is not so much in evil
dence on the ground because the
ground absorbs it. Every one who has
had occasion to walk through high
grass early on some spring or sum-
mer morning, can form some idea of
the quantity of water deposited in
sing night in the form of dew
some hundreds Of gallons to the acre,
1 should think. In my first chapter
I have not only shown that dry earth
absorbs moisture from the atmos-
phere. but actually measured the
amount absorbed.
Now. to come to the point. through
soil that has been mellowed by un-
derdrainage. the air can circulate
much more freely than 1t can
through compact soil. and the
warm moisture laden air, passing
deep into and out Of the cooler soil,
leaves a good part of its moisture in
the soil right where the roots Of the
crop can take 1t up. The admission
Of air adds fertility. to the soil, and 1t
also helps to break down the manurial
matters contained in the soil and
adapt them to the needs of the crop;
but to go further into this subject is
not within the province of these
papers.
However, must convince those
who are in doubt as to what has
been said about the circulation of air
in the soil. that this Is no mere the
ory incapable of demonstration. The
pressure Of the atmosphere Is about
Is pounds to the square inch, vary
ing somewhat with changes Of the
weather; so If you could exhaust all
the air from a tight cask, the cask
would have to sustain a pressure ap-
preaching Is pounds for every square
inch of heads. sides and all else Oh
collapse from the pressure of the at
mosphere without. If you take a
piece Of gas pipe. place one end Of it
in q hole several feet deep, fill the
hole with earth and let it rain on it
until the earth about the pipe has
become packed to the density CT II
good soil, you can still blow through
the pipe and out into the soil with
your mouth. OF course If you were
10 drive the pipe into the ground
with a maui. dense plug of earth
would be forced into the end Of the
pipe which would resist all your ef-
forts at blowing. And SO even the
| slight variation in the atmosphere
| that affects tibet barometer-those va
riatlons due to heat and cold and the
winds-cause circulation Of air in the
soil. l Rave placed my hari al til.
outlet of one Of my main drains and
felt the CGCi air flowing our Of the
drain even when no water was being
discharged. There Is a simple aprt-
ratus used to illustrate the foregoing
facts, hut I cannot take space 10 show
ii here.
To be continued.