226 * C H E M ! 
was formerly attributed to the volatile alkali, belongs 
only to this neutral fait, of which we fhall afterwards treat r 
The liquid known in chemical laboratories by the name 
of cauftic, or fluor volatile alkali, and in pharmacy by 
that of volatile fpirit of fal ammoniac, is not pure am¬ 
moniac ; it confifts of this alkali diffolved in water. Dr. 
Prieftley has Ihewn, that, by the help of a gentle heat, 
this liquor may be made to give out a permanent gas ; 
and that the water deprived of this gas lofes its alkaline 
properties'. This aeriform fluid is ammoniac, and is 
known by the name of ammoniacal gas. Macquer has 
well obferved, that this body mutt be examined, in order 
to arrive at a knowledge of the properties of the volatile 
alkali. 
To obtain this elaftic fluid, a certain quantity of the 
liquid ammoniac is put into a fmall retort, or matrafs of 
glafs. A recurved tube is adapted to this veflel, and the 
extremity of the tube is plunged beneath the mercury of 
a pneumatic apparatus ; a veflel of glafs filled with the 
fame metallic fluid being inverted over its orifice. The 
bottom of the retort or matrafs is then heated, by means 
of burning charcoal, or the flame of fpirit of wine. The 
firft portion of elaitic fluid, confiding chiefly of the com¬ 
mon air contained in tile vcflel and tube, is differed to 
efcape; and when the ebullition of the fluid is llrong, 
the gas is to be colledled. The dillillation mult not be 
urged, fo as to caufe the water to pafs in the form of va¬ 
pour; or a fmall veflel fliouid be affixed in the middle of 
the tube of communication, which, being kept cool, 
may ferve to condenfe the aqueous vapour, and caufe 
the ammoniacal gas to pafs in a very pure and dry Hate. 
The gas obtained by this procefs refembles air in its 
tranfparency and elalticity, as long as it is kept above 
the mercury. It is rather lighter than the air of the at- 
mofphere, its fmell is penetrating, and its tafte is acrid 
and cauftic ; it readily and ftrongly changes the blue co¬ 
lour of violets, mallows, and radifhes, to a green ; but 
the alteration produced is lefs than when pure alkalis are 
ufed; it deftroys animal life, and .corrodes the fkin, if 
expol'ed for fome time to its aftion. 
Though it is incapable of maintaining combuffion, and 
extinguifhes bodies which are already on fire, yet it in- 
creafes the magnitude of the flame of a taper before ex- 
tinflion, producing a pale yellow colour round its edge, 
which proves that alkaline gas is partly inflammable. At 
.hit this light flame defcends from the top of the veflel 
to the bottom; if a lighted taper be only held to the 
orifice of the veflel filled with ammoniacal gas, the yel- 
lowflame will rife more than an inch above thatof thetaper. 
Ammoniacal gas is one of the elaftic fluids which are 
the molt fufceptible of dilatation by heat. Atmofpheric 
air does not combine with alkaline gas, but only mixes 
with and dilutes it. Water quickly abforbs ammoniacal 
gas. If the water be frozen, it immediately becomes 
fluid, and produces cold ; whereas, on the contrary, fluid 
water becomes heated by combination with this gas. 
Water faturated with gas, or liquid ammoniac, is known 
by the name of fluor and cauftic volatile alkali. We 
fhall hereafter fee that the ftrongefl and moll pure volatile 
alkali is produced by faturating diftilled water with this 
gas. Liquid ammoniac has the fame properties as the gas 
it holds in folution, but not in fo eminent a degree, be- 
caufe the galeous being much lefs llrong than the .fluid 
aggregation, the tendency to combine will, according to 
one of our laws of affinity, be much more llrong in the 
gas than in the ammoniac. 
The fulphure of ammoniac is produced by a diililla- 
,tion of a mixture of muriat of ammoniac, lime, and 
fulphur : this is called the fuming or fmoking liquor of Boyle. 
Mix in a marble mortar, three parts of lime flaked in 
the air and fifted, one part of muriat of ammoniac, and 
one half part of fublimed fulphur. Put the mixture 
into an earthen retort, and adapt a receiver. Begin the 
dillillation with a gentle fire : the firlt iiquor which pafies 
over is of a light yellow colour, and fumes or fmokes; 
2 , 
S T R Y. 
the fecond is of a deeper yellow, and is not fuming: then 
increafe the fire till the retort is red-hot. According to 
Berthollet, the fulphure of ammoniac owes its fuming 
quality to an uncombined mixture of ammoniac ; it ap¬ 
pears that the ammoniac which does not enter into com¬ 
bination, evaporates while it holds in folution hydro-ful- 
phure of ammoniac; but in contatt with air it quits 
this to combine with the air, which afterwards, if in 
fufficient quantity, diffolves the very precipitate which 
was juft formed. The fulphure of ammoniac may yet 
diffolve, in thd cold Hate, a confiderable quantity of lul- 
phur^ but in the fuming ftate,, that is, with an excefs of 
ammoniac, it diffolves fulphur enough to faturate that 
excels, and ceafes to fmoke. Sulphure of ammoniac fa¬ 
turated with fulphur, is of a dark colour and an oily 
confluence; fulphurated hydrogen precipitates no ful¬ 
phur even in that ftate ; upon the linaileft contafr of air 
adding upon the hydrogen, it grows white, turbid, and 
gives out fulphur. 
Ammoniac alone will not attack fulphur; hence we 
fee that it is by means alfo of fulphurated hydrogen that 
the triple combination is formed; that it ought to be 
called hydrogenated fulphure of ammoniac; and that s 
while it is fuming; it is fulphurated hydrogen with an 
excefs of ammoniac. Ammoniac unites with acids, and 
forms falts, fome of which do not cryftaliize. 
Experiments to demotjlrate the Nature of Ammoniac .—• 
i. Mix two parts of oxygenated muriatic acid gas, with 
one part by meafure of ammoniacal gas, in a veflel over 
mercury. When thefe come in contaft, a llrong deto¬ 
nation is produced, accompanied by a yellow flame : the 
two gafes are fo diminifhed in volume, that fcarcely a 
third part remains; a folid matter is formed which ad¬ 
heres to the fides of the veflel; this is muriat of ammo¬ 
niac. The gas which remains has neither the fmell of 
ammoniac, nor the colour of muriatic acid ; it no longer 
diffolves in water, nor maintains combuftion; it is there¬ 
fore real azotic gas. It is alfo obferved, that there is a 
clear tranfparent liquid condenfed on the fides of the vefi- 
fel, which is nothing but water, with a certain quantity 
of muriatof ammoniac in folution. 
2. Through fome ammoniac, liquid or diffolved in wa¬ 
ter, pafs fome oxygenated muriatic acid gas : there will 
immediately be produced, in the midll of the liquor, a 
multitude of little bubbles of elaftic fluid, which rife to 
thefurface, and are collected into a jar filled with water 
by means of a tube communicating with the bottle which 
contains fhe ammoniac. This gas is perfeflly fimilar to 
that which remained in the preceding experiment. 
3. Fill a long glafs tube three parts full of oxygenated 
muriatic acid; fill it up with liquid ammoniac, and in¬ 
vert it in a faucer or bowl full of water : the ammoniac, 
by its lightnefs, pafies through the oxygenated muriatic 
acid, but produces a rapid eftervefcence ; the elaftic fluid 
which occafions it colledls in, the upper part of the tube, 
and part of it fpreads in the bowl. The gas or produdt 
is the fame as the preceding. 
4. Pafs ammoniacal gas over oxyd of manganefe in pow¬ 
der, and made red-hot in a porcelain tube, communi¬ 
cating by a tube with an empty bottle plunged into ice ; 
red vapours in abundance are prefently produced, to 
which white vapours fucceed, which condenfe inlide the 
bottle into a white tranfparent liquid, with a faline pun¬ 
gent fmell: diftil this liquid to drynel's in a gentle heat; 
the produdl is infipid^ and without any fenfible odour: 
it is water. What remains in the retort is of a white 
colour; it is fufible over coals, and produces vapours of 
nitric acid with the addition of fulphuric acid, and of 
ammoniac with limetherefore it is nitrat of ammo¬ 
niac. The black oxyd of manganefe has changed its co¬ 
lour ; it is now of a pale brown, no longer producing 
oxygen gas by the a< 5 lion of fire. 
It is plain that in thefe experiments the ammoniac is 
decompofed,; that in the three firft, one of its principles 
only, the azot, being fet at liberty, is difengaged in the 
form 
