il the destruction is complete. Hence we see that true
economy requires that the manures of the stable, stye, and
poultry-house, should be protected from evaporation (as will be
hereafter described), as soon as possible after they are made.

LEACHING.

The subject of _leaching_ is as important in considering the _inorganic_
parts of manures as evaporation is to the organic, while leaching also
affects the organic gases, they being absorbed by water in a great
degree.

A good illustration of leaching is found in the manufacture of potash.
When water is poured over wood-ashes, it dissolves their potash which
it carries through in solution, making ley. If ley is boiled to dryness,
it leaves the potash in a solid form, proving that this substance had
been dissolved by the water and removed from the insoluble parts of the
ashes.

[How does water affect decomposing manures?

Does continued decomposition continue to prepare material to be leached
away?

How far from the surface of the soil may organic constituents be carried
by water?]

In the same way water in passing through manures takes up the soluble
portions of the ash as fast as liberated by decomposition, and carries
them into the soil below; or, if the water runs off from the surface,
they accompany it. In either case they are lost to the manure. There is
but a small quantity of ash exposed for leaching in recent manures; but,
as the decomposition of the organic part proceeds, it continues to
develope it more and more (in the same manner as burning would do, only
slower), thus preparing fresh supplies to be carried off with each
shower. In this way, while manures are largely injured by evaporation,
the soluble inorganic parts are removed by water until but a small
remnant of its original fertilizing properties remains.

[What arrests their farther progress?

What would be the effect of allowing these matters to filter downwards?

What does evaporation remove from manure? Leaching?]

It is a singular fact concerning leaching, that water is able to carry
no part of the organic constituents of vegetables more than about
thirty-four inches below the surface in a fertile soil. They would
probably be carried to an unlimited distance in pure sand, as it
contains nothing which is capable of arresting them; but, in most soils,
the clay and carbon which they contain retain all of the ammonia; also
nearly all of the matters which go to form the inorganic constitu