^42 C H E M : 
flowly, giving out pujplifh fparks, and a beautiful green 
flame. It is foluble in one part and a half.of water. Of 
girths, barytes, potafli, and foda, decompofe it. This 
ialt has a ftrong pungent tafte. In a dry air, it lofes its 
water of cryftallization ; in a moiit, it attracts humidity. 
Like all other nitrats, it deflagrates on hot coals. When 
the heat rifes to rednefs, it begins to boil, and the acid 
is diffipated. 
Njtrat of Lime. —This is plentifully found in an¬ 
cient buildings, which have been long inhabited by men 
or animals. It is prepared by faturating nitric acid, with 
lime. Strain, and evaporate the liquor till it has nearly 
the confidence of a fyrup. Then leave it in a cool place; 
and it fettles in very long prifmatic cryftals, or rather in 
bundles of needles diverging from a common centie. In 
tafte it is acrid and bitter. 
Nitrat of lime, dried, melts over coals; in a ftate of 
perfeCf drynefs, it is very proper for drying gafes. It 
eafily melts by heat, merely with the aid of its own water 
of cryftallization; but the eifeft is hardly fenfible: it is 
decompofed almoft immediately, and nitric acid is diien- 
gaged. If carried into the dark after having been thus 
liquefied by heat, it becomes luminous, and in this ftate 
conftitutes the pbofpborus of Baldwin. 
Nitrat of lime, otherwife called calcareous nitrat, quick¬ 
ly attracts the moilhire of the air, and for that reafon it 
is neceflary to keep the cryftals of this fait in well-clofed 
vefl'els, which muit not be opened too frequently. It is 
very ioluble in water, two parts of cold, or lefs than one 
part of boiling water, being fufticient to hold it in folution. 
It is more eafily decompofed by charcoal than the nitric 
acid is ; for heat dilengages the nitric acid from the nitrat 
of lime in the form of an acid, whereas in other experi¬ 
ments, it is decompofed into its elements. 
Sulphuric acid decompofes nitrat of lime, the nitric 
acid palling off in white vapours : a folid mafs remains, 
and much caloric is difengaged. Sulphuric acid poured 
on a folution of calcareous nitrat, immediately produces 
a precipitate of fulphat of lime, and the nitric acid re¬ 
mains difengaged in the liquid. The aftion of other 
qcids on this fait is not known. Argil, barytes, potafti, 
loda, and ftrontian, decompofe it. The calcareous nitrat 
decompofes the neutral fulphuric alkaline (alts. 
This fait might be employed in medicine as a very ac¬ 
tive folvent, and fome chemical phyflcians affirm, that its 
application has-been attended with fuccefs. As the oxalic 
acid takes the lime from every other acid, and forms with 
it an infoluble compound, it is ufed as a teft of the pre¬ 
fence of lime, either free or in the ftate of combination. 
Nitrat of Ammoniac.— This is found fometimes in 
the mother-waters of nitre; but in general it is the pro¬ 
duction of art. It is prepared by the direit combination 
of nitric acid with ammoniac. To avoid wafte, it is bet¬ 
ter to ufe the carbonat than the pure ammoniac, becaufe 
there is an efl’ervefcence and a ftrong heat, which the car¬ 
bonat tempers. Its cryftals are prifms of fix fides, ter¬ 
minated with hexangnlar pyramids. Its tafte is bitter, 
penetrating, and urinous : it is very flexible under the 
peftle like.all the ammoniacal falts. When expofed to the 
aCtion of fire, it lofes its water of cryftallization, and 
gives out aqueous vapours. Thrown on a red-hot iron, 
it catches flame, which is not the cafe with the other ni¬ 
trats ; it makes a confiderable hilling, and the flame is 
yellow and very vivid. Making the experiment with a 
pneumatic apparatus, there firft pafles over a little water; 
then fome oxygen gas is produced ; and, la lily, there is 
a pretty loud detonation. It will not be prudent to try 
the experiment with any large quantity of .matter. 
This fait is deliquefcent, orliable to melt of itfelf, ef- 
pecially in winter. It is very foluble in water; unites 
with, and melts ice, producing a confiderable degree of 
cold. Half its weight of hot water is required to diffolve 
it, and twice its weight of cold ; it cryltaliizes irregular¬ 
ly by cooling, but the moll perfeCt cryftals are obtained 
by Ipontaneous.evaporation. If this fait be mixed with 
* 
S T R Y, 
fulphur or charcoal, and heated in an apparatus proper 
for obtaining gafes, the oxygen adts on thefe fubftances in 
fuch a manner that the nitrat of ammoniac is not decom¬ 
pofed : carbonic acid and ammoniac are obtained; azot 
is difengaged. 
Sulphuric acid decompofes nitrat of ammoniac; fulphat 
of ammoniac is obtained, and nitric acid is fetfree. Mu¬ 
riatic acid makes it undergo a change, but with different 
refults: the muriatic acid adts firft on the nitric acid, from 
which it takes a part of its oxygen, and converts it into 
nitrous acid ; oxygenated muriatic acid is therefore form¬ 
ed, which volatilifes by the help of the caloric, and the 
muriat of ammoniac, which is in folution in the water. 
With two parts of nitrat of ammoniac, and one of mu¬ 
riatic acid, a liquor is made which will diffolve gold. In 
this cafe, the decompolition of the nitrat of ammoniac 
takes place in a different manner: the oxygen of the ni¬ 
tric acid immediately attacks the gold ; the oxyd of gold 
thereby formed diffolves by degrees in a portion of the 
muriatic acid. By precipitating this folution of gold 
with a fixed alkali, aurum fulminant, ororat ot ammoniac, 
is produced ; for the alkali not only decompofes the mu¬ 
riat of gold, but alfo the muriat of ammoniac; fo that, 
as the oxyd of gold is feparated, it unites with the am¬ 
moniac, and forms that peculiar combination of which 
we have juft fpoken. 
Barytes, lime, magnefia, foda, and ftrontian, decom- 
pofe nitrat of ammoniac by uniting with its acid ; hence 
refult different nitrats and pure ammoniac, as appears by 
its lively and pungent flnell. This decompolition is made 
in the cold, and is effected by triturating that fait with 
thofe fubftances dry, as lime," potafli, See. With mag- 
nefia, a triple fait is produced, ammoniaco-magnefian 
nitrat. This fait niuft not be prepared in veffels ot me¬ 
tal, efpeciaily of iron and copper, as it tafily d:lfo ves 
them. The nitrat of ammoniac has net hitherto been 
applied to any ufe. 
Nitrat of Magnesia.— This is fomeiimes found 
native, but always in fmali quantities. It is formed by 
carbonat of magnefia made cauftic by an alkali, and then 
mixed to faturation with nitric acid. It has a bitter tafte, 
fomewhat like nitrat of lime. It is very foluble in wa¬ 
ter, requiring but one half of its weight at molt to dif¬ 
folve it: it cryltaliizes in cooling, or by evaporating the 
acid with the heat of the fun ; its cryftals are quadran¬ 
gular oblique prifms without pyramids ; but molt com¬ 
monly they are in needles, yet fo connected together as 
to prefent no determinate form. Expofed to heat in clof- 
ed vefl'els, it produces at firft fome bubbles of oxygen gas 
and nitrous-acid vapours; but the nitric acid foon palfes 
over without decompofition, and the magnefia remains 
difengaged in the retort. A linall heat is fufticient for 
the decompofition of nitrat of magnefia, which theas 
that its elements have no great affinity for each other ; 
it fhews alfo that magnefia lias not a tendency to unite 
with the nitrous acid, like lime, barytes, Sec. This fait 
is deliquefcent in the air. 
Sulphuric acid decompofes nitrat of magnefia, by tak¬ 
ing away its bafe. Muriatic acid decompofes it alio, but 
not by taking away the bafe: it attacks the nitric acid, 
and forms oxygenated muriatic acid: the nitric,acid is 
difengaged in white vapours. The muriatic acid feizes 
upon the magnefia as fait as it is difengaged from its acid, 
and forms with it a muriat of magnefia. It is alfo de¬ 
compofed by barytes, potafti, foda, lime, and ftrontian; 
ammoniac does not precipitate it completely ; for, as foon 
as the> - e is enough o’ the ammoniac to form a triple fait 
with the nitrat of magnefia, the precipitation ceafes, be¬ 
caufe the ammoniac cannot entirely decompofe the nitrat 
of magnefia; and, by adding more ammoniac, it would 
produce no etfeCt. What farther proves that the ammo¬ 
niac cannot decompofe all the nitrat of magnefia, is that, 
after the precipitation has ceafed with the action of am¬ 
moniac, more' magnefia may be precipitated by another 
alkali. The other alkalis precipitate magnefia in very 
