50 
MANURES. 
Magnesia, 
Olay, 
Sulphuric, or sulphur united tc 
| oxygen. 
j Muriatic, essentially composed of 
) chlorine. . 
Iron, 
Manganese, 
Silex, or the earth of flints. 
Now if we throw out the carbonic acid, which has 
been formed in burning, we have left in ashes three 
acids, which are united with he bases, and may form 
the following salts in plants, namely :—Glauber’s salt, 
Epsom salt, common table salt, bonedust, a salt of 
lime, and what we may term a bonedust salt of iron, 
or phosphate of iron, plaster of Paris, or gypsum, 
copperas, alum, and some other salts, which need not 
be enumerated. Our list comprises the principal, and 
those most likely to be used in farming. Well, now, 
the lesson to be drawn from this composition of ashes 
is this, that there is scarcely any salt occurring in 
commerce, which may not be used in agriculture, 
instead of those found in ashes. In fact, almost all 
salts which occur in a large way, as refuse materials 
from manufactures or other sources, have been used, 
and all with greater or less success, as manures. And 
if you cast your eye over the acids and bases of com¬ 
mon ashes, this seems quite reasonable. It is not 
expected that a plain farmer, possessing little or no 
chemical knowledge, should be able to tell before¬ 
hand what the effect of a salt would be, applied to 
his land ; but if he understands what the composition 
of ashes is, he may be sure that in any quantity in 
which the salt is likely to occur, it cannot be injurious, 
provided it is mixed up with plenty of mould, and a 
little ashes, or alkali, which will kill or neutralize any 
excess of the poisonous acid. 
In ashes, we have one part which may be leached 
out, and a part which remains after leaching, called 
spent ashes. Let us see then, in leaching, what parts 
