tion, though sure, would be slow
in operation. A loamy, light, well pulverized soil, again, would perhaps
furnish the best medium for the diffusion of water in this way.

It is impossible to set limits to so uncertain a power as this of
capillary attraction. We see that in minute glass tubes, it has power
to raise water a small fraction of an inch only. We see that, in the
sponge or flower-pot, it has power to raise water many inches; and we
know that, in the soil, moisture is thus attracted upwards several feet.
By observing a saturated sponge in a saucer, we shall see that, although
moist at the top, it holds more and more water to the bottom. So, in the
saturated earth in a flower-pot, the earth, merely moist at the surface,
is wet mud just above the water-table. So, in drained land, the
capillary force which retained the water in the soil to the height of a
few inches, is no longer able to sustain it, when the height is
increased to feet, and a portion descends into the drain, leaving the
surface comparatively dry.

Thus, it would seem, that draining may modify the force of capillary
attraction, while it cannot affect that of adhesive attraction. It may
drain off surplus water, but, unaided, can never render any arable land
too dry. If, however, the surplus water be speedily taken off by
drainage, and the capillary attraction be greatly impaired, so that
little water is drawn upwards by its force, will not the soil soon
become parched by the heat of the sun, or, in other words, by
evaporation?

Without stopping in this place, to speak of evaporation, we may answer,
that, in our burning Summer heat, the earth would be burnt up too dry
for any vegetation, were it not for a beneficent arrangement of
Providence, which counteracts the effect of the sun's rays, and of which
we will now make mention.

_Power to imbibe moisture from the air._--We have spoken, in another
place, of the absorption, by drained land, of fertilizing substances
from the atmosphere. Dry soil has, too, a wonderful power of deriving
moisture from the same source.

"When a portion of soil," says Johnston, "is dried carefully over
boiling water, or in an oven, and is then spread out upon a sheet
of paper in the open air, it will gradually drink in watery vapor
from the atmosphere, and will thus increase in weight.

"In hot climates and in dry seasons, this property is of great
importance, restoring as it does, to th