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154 
elements, into prussic acid and water. Ammonia 
forms urea, or the characteristic substance of 
urine, with cyanic acid, and a series of crystal- 
line compounds with the volatile oils of mustard 
and bitter almonds; and it changes into splendid 
blue or red colouring matters when in contact 
with the bitter principle of the bark of the apple 
tree’s root, with the sweet principle of the lichen 
dealbatus, or with the insipid matter of the true 
dyer’s orchall. But by far the most interesting 
transformation of ammonia—and one which the 
other transformations are of value chiefly for illus- 
trating—is its evolving itself from the putrefac- 
tion of all animal matter, and contributing its 
azote to the formation of gluten, albumen, and 
other nitrogenous substances of the most nutri- 
tious parts of plants. 
| Ammonia achieves its grand office on the farm, 
not alone as a principal ingredient in all animal 
manure, but as an element in atmospheric vapours, 
in rain, and in snow. It is the final product of 
the decay of all animal substances, and goes off 
| from their decomposition as a gas in union with 
| carbonic acid into the atmosphere. In the tro- 
| pics, indeed, it frequently combines with oxygen 
to form nitric acid, and therefore suffers a trans- 
| formation into the very opposite of its proper 
or alkaline character; yet even there it ascends 
_ largely, and in the other zones of the world it 
ascends wholly, into the atmosphere in its strictly 
ammoniacal condition, and becomes dissolved in 
the vapours which descend to the earth in rain and 
snow. Nitrogen is a very large element in every 
| animal body; it is separated from the other ele- 
ments in every process of decomposition, whether 
| by exudation or excrementition in the living 
body, or by putrefaction in the dead carcass; it 
has a stronger affinity for hydrogen than for any 
other element ; and on being liberated from any 
animal organism by decomposition, it instantly 
| rushes into combination with the hydrogen of 
any aqueous matter in its vicinity, and so forms 
ammonia, the simplest and the most. facilely con- 
stituted of all nitrogenous compounds. As ra- 
pidly therefore as any animal substance decays, 
so rapidly does ammonia rise out of all its nitro- 
| gen, and either combine with adjacent acids to 
form ammoniacal salts, or mount into the atmo- 
sphere as a gas. Its gaseous evolution, in the 
instances of old urine, stable dung, and some 
others, is so pungently and stingingly sensible as 
to be known to every observer; and, though not 
sensible in other instances, may either be in- 
ferred from analogy, or proved by appeal to some 
general facts,—and principally to the existence 
of a larger proportion of ammonia in rain-water 
than can be accounted for upon any other hypo- 
thesis. 
“Experiments made in this laboratory with 
the greatest care and exactness,” says Dr. Liebig 
in reference to his own laboratory at Giessen, 
“have placed the presence of ammonia in rain- 
water beyond alldoubt. It has hitherto escaped 
AMMONIA. 
observation, because it was not searched for. 
All the rain-water employed in this inquiry was 
collected six hundred paces south-west of Gies- 
sen, whilst the wind was blowing in the direction 
of the town. When several pounds of it were 
distilled in a copper still, and the first two or 
three pounds evaporated with the addition of a 
little muriatic acid, a very distinct crystallization 
of sal ammoniac was obtained; the crystals had 
always a brown or yellow colour. Ammonia may 
likewise be always detected in snow-water. Crys- 
tals of sal ammoniac were obtained by evaporating 
in a vessel with muriatic acid several pounds of 
snow, which were gathered from the surface of 
the ground in March, when the snow had a depth 
of ten inches. Ammonia was set free from those 
crystals by the addition of hydrate of lime. The 
inferior layers of snow resting upon the ground 
contained a quantity decidedly greater than those 
upon the surface. It is worthy of observation 
that the ammonia contained in rain and snow 
water possesses an offensive smell of perspiration 
and putrifying matter,—a fact which leaves no 
doubt respecting its origin. Hitinefield has proved 
that all the springs in Greifswalde, Wick, Eldena, 
and Kostenhagen, contain carbonate and nitrate 
of ammonia. Ammoniacal salts have been dis- 
covered in many mineral springs in Kissingen 
and other places. The ammonia of these salts 
can only arise from the atmosphere. Any one 
may satisfy himself of the presence of ammonia 
in rain by simply adding a little sulphuric or 
muriatic acid to a quantity of rain-water, and by 
evaporating this nearly to dryness in a clean por- 
celain basin. The ammonia remains in the resi- 
due in combination with the acid employed ; and 
may be detected either by the addition of a little 
chloride of platinum, or, more simply, by a little 
powdered lime, which separates the ammonia, 
and thus renders sensible its peculiar pungent 
smell. The sensation perceived upon moistening 
the hand with rain-water, so different from that 
produced by pure distilled water, and to which 
the term softness is vulgarly applied, is also due 
to the carbonate of ammonia contained in the 
former.” “We cannot doubt,” says Saussure, 
“that ammonia exists in the atmosphere; for we 
know that sulphate of alumina (common alum) 
is gradually converted into ammoniacal alum by 
exposure to the air.” Other distinguished chem- 
ists have repeated Dr. Liebig’s experiments upon 
rain-water ; and have, like himself, not only found 
it to contain ammonia, but very distinctly recog- 
nised in the ammonia yielded by it the offensive 
odour of animal perspiration, excrements, and 
putrefaction. ‘The ammonia evolved from the 
decay of animal matter rushes into combination 
with carbonic acid to form carbonate of ammo- 
nia, or the vapour or volatile matter of what is’ 
popularly termed smelling salts; and in this state, 
it is so exceedingly soluble in water that it must 
immediately deliquesce in the humid vapours 
with which it meets, and be held in mechanical 
