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lime, or powdered limestone ought to be applied, 
depends upon the quantity of calcareous matter 
already in the soil. All soils are improved by mild 
lime, and ultimately by quicklime, which do not 
effervesce with acids ; and sands more than clays. 
When a soil, deficient in calcareous matter, con- 
tains much soluble vegetable manure, the applica- 
tion of quicklime should always be avoided, as it 
either tends to decompose the soluble matters by 
uniting to their carbon and oxygene so as to be- 
come mild lime, or it combines with the soluble 
matters, and forms compounds, having less attrac- 
tion for water than the pure vegetable substance. 
The case is the same with respect to most animal 
manures ; but the operation of the lime is different 
in different cases, and depends upon the nature of 
the animal matter. Lime forms a kind of insolu- 
ble soap with oily matters, and then gradually de- 
composes them by separating from them oxygene 
and carbon. It combines likewise with the animal 
acids ; and probably assists their decomposition by 
abstracting carbonaceous matter from them com- 
bined with oxygene ; and consequently it must 
render them less nutritive. It tends to diminish 
likewise the nutritive powers of albumen from the 
same causes ; and always destroys to a certain 
extent the efficacy of animal manures, either by 
combining with certain of their elements, or by 
giving to them new arrangements. Lime should 
never be applied with animal manures, unless they 
are too rich, or for the purpose of preventing 
noxious effluvia, as in certain cases mentioned in 
the last Lecture. It is injurious when mixed with 
u 
