composition"? the metal robs the nitric arid 
of the greatest part of its oxygen, and be- 
comes oxydated. I be remainder of the acid 
having lost so much of its oxygen, be- 
comes so altered, that, at the usual tempe- 
rature, it can exist no longer in the liquid 
state, but instantly expands, and assumes the 
form of gas, ceasing at the same time to be an 
acid. 
It was mentioned before, that nitrous gas 
greedily attracts oxygen gas from atmosphe- 
ric air. During this union an acid is produced. 
Pass up into a tall cylindrical glass vessel 
over water, about one part of nitrous gas and 
two of common air. The two fluids will spee- 
dily unite, red fumes will be produced, and 
tiie volume of the two combined gases will be 
diminished. A considerable degree of heat 
will be perceived, the water will rise in the 
vessel, and absorb the red vapours. "When 
the two gases have mixed in proper propor- 
tion, nothing remains at last but the nitrogen 
gas of the atmospheric air. 
Usually sixteen parts of common air are re- 
quisite to destroy' completely seven of nitrous 
gas ; tins, however, varies according to the 
purity of the atmospheric air. 
The nitrous gas, in this experiment, decom- 
poses the atmospheric air ; it takes the oxy- 
gen gas from the nitrogen gas, unites with it, 
and forms nitrous acid. The nitrous gas is 
therefore left behind ; the heat which is ge- 
nerated, is that which kept the gases in solu- 
tion, which is now set free. 
If, instead of atmospheric air, oxygen gas 
is used, this experiment will be still more 
striking, and the gases will almost entirely dis- 
appear. 
Upon this property which nitrogen gas has, 
of absorbing the oxygen of the atmosphere, 
Priestley formed the eudiometers, already 
mentioned. 
Gaseous oxyd of azote, or nitrous 
oxyd. The union of azote, or nitrogen and 
oxygen, which we considered before under 
the name of nitrous gas, does not constitute 
the first degree of oxygenation of nitrogen. 
There is another degree below this. This 
was formerly called dephlogisticated nitrous 
gas, but now gaseous oxyd of nitrogen, or 
nitrons oxyd. It was first discovered by 
Priestley. 
Professor Davy has examined with great 
^accuracy the formation and properties of all 
the substances concerned in its production ; 
and to him we are indebted for a thorough 
knowledge of this gas. We shall describe its 
principal properties as we find them in his 
Researches. 
Gaseous oxyd of nitrogen is a permanent 
gas. A candle burns in it with a brilliant 
flame and crackling noise : before its extinc- 
tion the white inner flame becomes surround- 
ed with a blue one. Phosphorus introduced 
to it in a state of inflammation bums with in- 
creased splendour, as in oxygen gas. Sulphur 
introduced into it when burning with a feeble 
blue flame, is extinguished ; but when in a 
state of vivid inflammation it burns with a 
rose-coloured flame. Lighted charcoal burns 
in it more brilliantly than in atmospheric air. 
Iron wire with a small piece of wood affixed 
to it, and introduced inflamed into a vessel 
filled with this gas, burns rapidly, and throws 
out bright scintillating sparks.' 
Nitrous oxyd is rapidly absorbed by water 
which has been boiled ; a quantity of gas equal 
to rather more than half the bulk of the water 
may be thus made to disappear: the water 
acquires a sweetish taste, but its other pro- 
perties do not differ perceptibly from com- 
mon water. The whole gas may be expelled 
again by heat. It does not change blue ve- 
getable colours, it has a sweet taste, and a 
faint but agreeable odour. 
'Phis gas explodes with hydrogen, when 
electric sparks are- made to pass through the 
mixture. 
Animals, when confined wholly in this gas, 
give no signs of uneasiness at first, but they 
soon become restless, and then die. 
When it is mingled with atmospheric air, 
and then received into the lungs, it generates 
highly pleasurable sensations : the effects it 
produces on the animal system are very ex- 
traordinary. It excites the body to action, 
and rouses the faculties of the mind, inducing 
a state of great exhilaration, an irresisti- 
ble propensity to laughter, a rapid flow of 
vivid ideas', and unusual vigour and fitness 
for muscular exertions, in some respects re- 
sembling the sensations attendant on intoxica- 
tion, without any languor, depression of spi- 
rits, or disagreeable feelings afterwards, but 
more generally followed by vigour, and a dis- 
position to exertion, which gradually subsides. 
The accounts of these wonderful effects, 
which, when first announced, were scarcely 
credited, have been confirmed In a variety of j 
experiments, so as to be past all kind of 
doubt. 
This gas is produced when substances, 
having a strong affinity with oxygen, are 
added to nitric acid, or to nitrous gas. It may 
therefore be obtained by various methods, in 
which nitrous gas or nitric acid is decomposed 
by substances capable of attracting the greater 
part of their oxygen. The most commodious 
and expeditious, as well as the cheapest mode 
of obtaining it, is by decomposing nitrate of 
ammonia by- heat in the following manner : 
Put into a glass retort some pure nitrate of 
ammonia, and apply to it an Argand’s lamp ; 
the salt will soon liquefy, and when it begins 
to boil gas will be evolved. Increase the heat 
gradually, till the body and neck of the retort 
become filled. with a milky-white vapour. In 
this state the temperature of the fused nitrate 
is between 340 and 480 degrees. After the 
decomposition has proceeded for some mi- 
nutes, so that the gas, when examined, quick- 
ly enlarges the flame of a taper, it may be col- 
lected over water. Care should be taken du- 
ring the whole process never to suffer the tem- 
perature of the fused nitrate to rise above 500 
degrees Fahrenheit, which may be easily judg- 
ed of from the density of the vapours in the re- 
tort, and from the quick ebullition of the fused 
nitrate ; for if the heat is increased beyond 
this point, the vapours in the retort acquire a 
reddish and more transparent appearance, and 
the fused nitrate begins to rise, and occupy 
twice the bulk it did before. The nitrous 
oxyd, after its generation, should stand over 
water for several hours, and is then fit for re- 
spiration, or other experiments. 
To experience its effects in breathing it, put 
about a gallon into a large bladder, or oiled 
silk hag, having a tube attached to it of three- 
fourths of an inch in diameter. First, the 
common air must be expelled from the lungs, 
before the tube is received into the mouth, 
and the nostrils must be accurately closed 
with the hand. It must then be breathed 
backwards and forwards into the bag for a tew 
minutes. 
SuttmjREGV* ac: in cas is no where 
found in a natural state, ana is entirely a pro- 
duction of art. 
It is obtained by exposing to heat in a re- 
tort, sulphuric acid, while it is exercising an 
action on some combustible body, such as 
oil, charcoal, mercury, &c. ; in a word, on 
such bodies as can take up a portion of the 
oxygen combine^ with the sulphur contained 
in that acid. It is sulphur combined with a 
less quantity of oxygen tlian that which is ne- 
cessary to make it sulphuric acid ; the com- 
bustible body, therefore, takes a part of its 
oxy r gen from the sulphuric acid, which, by 
these means, becomes sulphureous acid ; and 
caloric combining with this acid, causes it to 
assume the gaseous form. This process re- 
quires a mercurial apparatus, because this gas 
is entirely soluble in water. , 
Sulphureous acid gas is more than twice as 
heavy as atmospheric air. It extinguishes 
burning bodies, and suffocates animals im- 
mersed in it. It first reddens, and then de- 
stroys most of the vegetable colours. It lias 
the property of whitening silk, and giving it ’a ’ 
lustre. 
Sulphureous acid gas combines with alkalis, I 
and forms with them neutral salts, which differ 
from those produced by the sulphuric acid and 
the same alkalis, in their form, their savour, 
and particularly their property of being de- 
composed by the weakest acids, and even the ; 
acetous acid. 
Muriatic acid gas is obtained by ex- j 
posing to heat filming muriated acid, put into- 
a retort, the beak of which is introduced be- ] 
low a bell filled with mercury, and placed on 
the shelf of a mercurial pneumatic apparatus. ] 
You may obtain it also with the same appa- 
ratus, if, instead of muriatic acid, you expose j 
to heat a mixture of muriate of soda, or ma- I 
rine salt ami- sulphuric acid; the sulphuric 3 
acid combines with the soda the base of the ] 
marine salt, and the muriatic acid remaining j 
free, passes into the state of muriatic acid ] 
gas. 
Muriatic acid gas is perfectly soluble in | 
water, and in a very short time. If you j 
therefore introduce into the bell in which the ] 
gas has been collected, a small quantity of j 
water, the latter, by its relative lightness, will I 
rise to the surface of the mercury ; the gas I 
will be immediately absorbed entirely, and clis- I 
solved in the water; the mercury will ascend | 
towards the top of the bell ; and the liquor j 
found above the mercury will be real muriatic J 
acid, more highly concentrated, according as I 
there is more gas and less water. 
Muriatic acid gas, therefore, is nothing else ] 
than the muriatic acid itself deprived of Water ; 1 
that is to say, as much concentrated as possible, j 
and combined with caloric, which cause 3 it to I 
assume the gaseous form. 
Muriatic acid gas has a sharp pungent j 
odour. If a little of it is mixed with atmo- j 
spheric air, it produces, like the muriatic acid, 1 
white fumes or vapours, occasioned by the 1 
combination of the gas with the moisture of 
the air. 
The base of the muriatic acid gas is strongly ] 
combined with oxygen, for which it has so ] 
great an affinity, that it cannot be separated * 
from it, The nature of this base is therefore i 
unknown. Its affinity for oxygen is so strong, i 
that it can even combine itself with a larger ! 
quantity of oxy gen than is necessary to consti- 
tute an add, and it then appears in the form 
of oxygenated muriatic gas. 
