Chloride of lime is a compound of lime and chlorine. It furnishes both of these constituents to plants, and it is an excellent absorbent of ammonia and other gases arising from decomposition—hence its usefulness in destroying bad odors, and in preserving fertilizing matters for the use of crops.
It may be used like plaster, or in the decomposition of organic matters, where it not only hastens decay, but absorbs and retains the escaping gases. It will be recollected that chloride of lime is one of the products of the lime and salt mixture.
Lime in combination with phosphoric acid forms the valuable phosphate of lime, of which so large a portion of the ash of grain, and the bones of animals, is formed. This will be spoken of more at length under the head of 'phosphoric acid.'
MAGNESIA.
Magnesia is a constituent of vegetable ashes, and is almost always present in the soil in sufficient quantities. When analysis indicates that it is needed, it may be applied in the form of magnesian lime, or refuse epsom salts, which are composed of sulphuric acid and magnesia (sulphate of magnesia).
The great care necessary concerning the use of magnesia is, not to apply too much of it, it being, when in excess, as has been previously remarked, injurious to the fertility of the soil. Some soils are hopelessly barren from the fact that they contain too much magnesia.
ACIDS.
SULPHURIC ACID.
What is sulphuric acid commonly called?
How may it be used?