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?