ich have
been leached, contain much potash, soda, etc.

Farmers have generally overrated the value of leached ashes, because
they contain small quantities of available phosphate of lime, and
soluble silicates, in which most old soils are deficient. While we
witness the good results ensuing from their application, we should not
forget that the fertilizing ingredients of _thirty bushels_ of these
ashes may be bought in a more convenient form for _ten_ or _fifteen
cents_, or for less than the cost of spreading the ashes on the soil. In
many parts of Long Island farmers pay as much as eight or ten cents per
bushel for this manure, and thousands of loads of leached ashes are
taken to this locality from the river counties of New York, and even
from the State of Maine, and are sold for many times their value,
producing an effect which could be as well and much more cheaply
obtained by the use of small quantities of super-phosphate of lime and
potash.

These ashes often contain a little charcoal (resulting from the
imperfect combustion of the wood), which acts as an absorbent of
ammonia.

It is sometimes observed that _unleached_ ashes, when applied in the
spring, cause grain to lodge. When this is the case, as it seldom is, it
may be inferred that the potash which they contain causes so rapid a
growth, that the soil is not able to supply silicates as fast as they
are required by the plants, but after the first year, the potash will
have united with the silica in the soil, and overcome the difficulty.

OLD MORTAR.

[What are the most fertilizing ingredients of old mortar?]

_Old mortar_ is a valuable manure, because it contains nitrate of potash
and other compounds of nitric acid with alkalies.

These are slowly formed in the mortar by the changing of the nitrogen of
the hair (in the mortar) into nitric acid, and the union of this with
the small quantities of _potash_, or with the _lime_ of the plaster.
Nitrogen, presented in other forms, as ammonia, for instance, may be
transformed into nitric acid, by uniting with the oxygen of the air, and
this nitric acid combines immediately with the alkalies of the
mortar.[AI]

The lime contained in the mortar may be useful in the soil for the many
purposes accomplished by other lime.

GAS HOUSE LIME.

[How may gas-house lime be prepared for use?

Why should it not be used fresh, from the gas house?

On what do its fertilizing properties depend?

What use may be made