A PRIZE ESSAY. 
21 
and growing roots, in order that they may obtain from 
the soil the salts they want. 
If well-rotted manure contains abundance of these 
salts, ready formed in its mould, then there will be 
less necessity of this action of carbonic acid. But here 
again it must be remembered, that this abundance of 
salts, ready formed in mould, can be produced only 
at the expense of great loss by fermentation of real 
valuable parts; for, 
2d. The next great action of the mould of cattle 
dung is, to produce or form ammonia. This plays a 
threefold part: its first action is, to render the mould 
more soluble; this action it possesses in common with 
the fixed alkalies—potash and soda. All the alkalies 
put a large, but undefined portion of mould, into a 
state fit to become food for plants. The second action 
of ammonia is this, it hastens decay. It is the bel¬ 
lows, we may say, kindling the*slow mouldering fire. 
The third action of ammonia is, to combine with any 
free acids, such as vinegar, or even an acid formed of 
mould itself, but especially with aqua-fortis, or nitric 
acid, which is always produced where animal or vege¬ 
table matters decay. This is a highly important fact. 
The result of this action, the production of ammonia 
and aqua-fortis, during the formation of mould, is, 
that a kind of saltpetre is thereby produced. That is, 
the ammonia and aqua-fortis unite, and form a salt, 
with properties similar to saltpetre. But we want the 
first and second action of ammonia to occur, before 
the third takes place. Consider now, reader, whether 
a more beautiful and effectual way can be devised, to 
hasten decay, and render mould more fit for nourish¬ 
ing plants, than this which nature has provided. The 
ammonia is volatile. It remains, not like potash and 
soda, where it is put, incapable of moving unless dis¬ 
solved by water, but ammonia, like steam, pervades 
every part. It is as expansive as steam. Heated up 
by the slow mouldering fire of decay, it penetrates 
the whole mass of mould. It does its work there. 
