led with round stones, or with musket balls, or with
large shot, and with water to the surface, and then an opening be made
at the bottom of the cask, all the water, except a thin film adhering to
the surface of the vessel and its contents, will immediately run out.

If now, the same cask be filled with the dried soil of any cultivated
field, and this soil be saturated with water, a part only of the water
can be drawn out at the bottom. The soil in the cask will remain moist,
retaining more or less of the water, according to the character of the
soil.

Why does not the water all run out of the soil, and leave it dry? An
answer may be found in the books, which is, in reality, but a
re-statement of the fact, by reference to a principle of nature, by no
means intelligible to finite minds, called attraction. If two substances
are placed in close contact with each other, they cannot be separated
without a certain amount of force.

"If we wet the surfaces of two pieces of glass, and place them in
contact, we shall find that they adhere to each other, and that,
independently of the effect of the pressure of the air, they oppose
considerable resistance to any attempt to separate them. Again, if
we bring any substance, as the blade of a knife, in contact with
water, the water adheres to the blade in a thin film, and remains,
by what is termed _adhesive attraction_. This property resides in
the surface of bodies, and is in proportion to the extent of its
surface.

"Soils possess this property, in common with all other bodies, and
possess it, in a greater or less degree, according to the aggregate
surface which the particles of a given bulk present. Thus, clay
may, by means of kneading, be made to contain so large a quantity
of water, as that, at last, it may almost be supposed to be divided
into infinitesimally thin layers, having each a film of water
adhering to it on either side. Such soils, again, as sand or chalk,
the particles of which are coarser exert a less degree of adhesive
attraction for water."--_Cyc. of Ag._, 695.

Professor Schuebler, of Tubingen, gives the results of experiments upon
this point. By dropping water upon dried soils of different kinds, until
it began to drop from the bottom, he found that 100 lbs. of soil held by
attraction, as follows:

Sand 25 lbs. of water.
Loamy Soil 40 "