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the slow combustion of ammonia by which nitric acid is formed ; but this com¬ 
bustion takes place only at high temperatures. M. Kuhlman announced to the 
Academy of Sciences that he had found nitrate of ammonia among the products 
of the putrefaction of animal matter, and claimed it to be one of the products of 
the decomposition ; but this is disproved by other chemists of note, and no doubt 
in most cases the nitrification of soils is owing either to some peculiar and 
permanent cause, or else rests upon a principle with which we are not fully 
acquainted; and although this acquaintance might be of little practical value, 
nevertheless as having a bearing upon the great question before us, we thought 
it worth while to notico it briefly here.] 
The peculiar province of manures, as lias already been shown, is to 
furnish the plant for assimilation at once, what it would otherwise obtain 
only by the slow process of absorption from the atmosphere in insuffi¬ 
cient quantities, which would lessen materially the productiveness of the 
plant, as Nature always requires the same elements to produce the same 
results ; for instance, if there is not sufficient phosphoric acid in an acre 
of ground to produce forty bushels of wheat, although every other ne¬ 
cessary element may be even in excess, still the forty bushels will not be 
produced. Here we see the vast advantage that complex manures pos¬ 
sess over those simple in their nature, and for this reason we begin with 
organic manures, which contain all the elements composing the organi¬ 
zation ; but before noticing the characteristics of the different organic 
manures, allow me to offer some suggestions of a more general nature— 
and first, as to the 
Preservation of Manure .—In all well-regulated agricultural establish¬ 
ments the preservation of manure is a question of vital importance, and 
TTe can almost infallibly judge of the thrift and prudence of a farmer by 
his dung-heap, for a farmer of forethought will at once perceive that a 
slight outlay here will be amply repaid in the increased productiveness 
of his farm ; but instead of this care in the production and preservation 
of manure, how often does it seem that the dung-heap is exposed as 
though it was a matter of the utmost consequence that it should be 
leLched as thoroughly as possible, exposed not only to the weather, but 
so placed that the eaves of the barn will pour upon it, and wash away 
the very principle of fertility into the gutter, where its effects may be 
traced all summer by the increased verdure that lines its path. 
V 
The practice of heaping up the farm yard manure in large heaps, and 
adding to it constantly for a year, is positively injurious. Manure should 
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