AERO 
he found that it was much fooner produced by making ufe 
of a weak folution of copper ; by putting iron into which, 
he obtained that fpecies of nitrous air .called dephlogijli- 
cated. 
Of Nitrous Air . 
This kind of air is plentifully obtained in all cafes where 
the nitrous acid is combined with phlogifton. Thus, when 
it is mixed with metals, or animal or vegetable fubftances, 
nitrous air is produced in great quantities; but very fpa- 
ringly when treated with metallic calces, earths, or other 
matters, which are faid to contain little or no phlogifton. 
All the metals, except gold, platina, and regulus of anti¬ 
mony, which are not foluble in the pure nitrous acid, 
yield nitrous air on being treated with it; and, even from 
thefe, when difl'olved in aqua regia, feme quantity of this 
air may be obtained. Every metal, however, does not 
yield it in equal quantity, with equal facility, or equally 
good. Silver, copper, iron, brafs, bifmuth or nickel, 
when put into nitrous acid, yield this air in confiderable 
quantity. Mercury yields it but (lowly without the ap¬ 
plication of heat, though no great degree of it is necclia- 
ry. Copper and iron, efpecially the hitter, require tire 
acid to be cautioully applied on account of the violent 
emillion of fumes. Gold, platina, and regulus of anti¬ 
mony, when put in aqua regia, yield nitrous air pretty 
readily; but lead yields it in (mailer proportion than any 
other metal; and zinc does the fame among the femi-me¬ 
tals, the elaltic fluid produced from it being mo (fly phlo¬ 
gidicated air. 
In the production of this kind of air, great differences 
are perceived by a diverlity in the (trength of the acid. 
Thus, if we diffblve copper in (Irong nitrous acid, no ni¬ 
trous air is produced, though the fame materials will yield 
air in great quantity by the mere atfufion of water to di¬ 
lute the acid. This is very properly explained by Doctor 
Prieftley, from the property that the nitrous acid has of 
attracting phlogifton, which is evident from what happens 
in the folution of mercury. When (irong fpirit of nitre 
is poured upon this metal, the folution foon begins, and 
is very rapid, yet not a Angle bubble of elaftic fluid is 
produced ; but in a fhort time the acid next to the mer¬ 
cury is changed of an orange-colour, which is an indica¬ 
tion of its having acquired phlogifton, probably from the 
nitrous air which is decompofed the moment it is formed, 
and before its particles are united into vilible bubbles. 
The bubbles of air indeed break through the coloured 
acid, but they difappear the moment they come in contact 
with the pale-coloured acid. As foon as the whole quan¬ 
tity of acid has aflumed the orange-colour, nitrous air es¬ 
capes from it in conliderable quantity; but the mixture 
of water deprives the acid of its power of decompoflng 
nitrous air. The (Irong and pale-coloured nitrous acid 
ought to be diluted with at lead two or three parts of wa¬ 
ter to one of the acid, for the eafy production of nitrous 
air from copper and mercury. For common experiments, 
except the latter be ufed, no other degree of heat is ne- 
ceflary than that produced by the effervefcence. 
Nitrous air is equally as invifibfe as common air, except 
at firft, when it is fomewhat coloured, owing to a little 
fuperfluous nitrous acid, or to fome earthy particles car¬ 
ried up with it. Its fmell refembles that of nitrous 
acid, or, indeed, is the very fame; becaufe, in parting 
through the common air to our noitrils, it is decompofed, 
and converted into nitrous acid. The fame is to be (aid 
of its take ; though M. Fontana, who tailed it without 
any contact of external air, affirms that it has no tafie 
whatever. Though nitrous air extinguifhes flame, it may 
be brought into fuch a date that a candle will burn in it 
with an enlarged flame; and it becomes what Dr. Pried- 
ley calls deghlogificated nitrous air , of which hereafter. 
Nitrous air is the mod fatal of any to animal life. Even 
infects, which can bear phlsgifticated and inflammable 
air, generally die the moment they are put into it. Frogs, 
fnails, and other animals which do not refpire very fre- 
Vol. I. No. 10. 
L O G Y. 15? 
quently, die in a few minutes, and feldom recover even 
when taken out of this noxious fluid before they are dead. 
Plants perifli very foon in nitrous air, and even in common 
air faturated with nitrous air; but Dr. Prienley informs 
us of one indance to the contrary, where the fuperfluous 
nitrous air-was let out under water, fo that no part of it 
was decompofed in contact with the water. 
By agitation in nitrous air, water may be made to im¬ 
bibe one-tenth of its bulk; and afterwards the nitrous 
air may be expelled again by boiling, though not in tire 
fame quantity as it was abforbed; but for this purpofe 
the water fliould be previoully deprived of its air. Dr. 
Priedley obtained about one-fourth part, fufficiently pure, 
and without any mixture of fixed air. Nitrous air is ob- 
forbed by drong vitriolic acid nearly in the fame quantity 
as by water; the acid acquiring a purple colour, by rea- 
fon of the phlogifton contained in the air. The drong 
nitrous acid abforbs it in great quantity; and becomes 
fmoking, orange-coloured, and afterwards green, on ac¬ 
count of the phlogidon contained in it. Ma j 1 eacid im¬ 
bibes but a filial 1 quantity, and very (lowly, acquiring at 
the fame time a light-blue colour. Both nitrous air and 
common air phlogidicated by it are meliorated by agita¬ 
tion in nitrous acid. 
Nitrous air is abforbed in confiderable quantity by the 
concentrated vegetable acid. A folution of vitriolated 
iron imbibes it in much greater quantity than water, and 
acquires a black colour; which, however, foon goes off 
by expofure to the common air. Its tade alfo becomes 
acid. Very little is abforbed by cauffic alkalies. Olive- 
oil flowly abforbs a confiderable quantity, but oil of tur¬ 
pentine much more. By a little agitation, it will imbibe 
more than ten times its quantity of nitrous air ; acquiring 
at the fame time a yellowilh or orange'colour, and be¬ 
coming a little glutinous. The part not abforbed appears 
to be converted into phlogidicated air. Ether and fpirit 
of wine abforb it very quickly, but no nitrous air is. ob¬ 
tained by the application of heat after they have abforbed 
it. It is greatly diminilhed by oil of turpentine, liver of 
fulphur, and pyrophorus ; all of which leave it in a phlo¬ 
gidicated (late. It is alfo diminilhed and phlogidicated by 
being kept in a bladder, alternately exported to moiflure 
and drynefs. Nitrous acid air has the fame effect. 
One of the molt remarkable properties of nitrous air is 
its diminution with dephlogilticated air; by which means 
it becomes a te(t of the quantity of that kind of air con¬ 
tained in the atmofphere. With pure dephlogidicated 
air, the diminution is almod to nothing, at the fame time 
that fome quantity of nitrous acid is reproduced by the 
decompolition of the nitrous air; but, as our atmofphere 
is always mixed with a confiderable quantity of phlogidi¬ 
cated air, on which nitrous air has no effect, the diminu¬ 
tion in this cafe is never fo confiderable. Upon this prin¬ 
ciple the Eudiometer isconftruCted. 
Another very remarkable property of nitrous air is its 
drong antifeptic power; infomuch that animal matter 
may be preferred by it for many months. It becomes 
however very offe.nfive both to the noitrils and palate, 
though the lmell is not altogether that of putrefaction. 
The fpecific gravity of nitrous air, as well as of other kinds, 
lias been afeertained by Mr. Kirwan. As it corrodes metals, 
he endeavoured to, find its weight by comparing the lofs 
fudained by the materials which produce it. Thus he 
found, that fourteen grains of the materials produced 
38-74 inches of nitrous air; and, confequently, by proper 
calculation, that the fpecific gravity of nitrous air is to 
that of atmofpheric air as 1195 to 1000. 
With regard to its conffituent principles, all thofe who 
regard phlogifton as a didinct fubdance have believed, 
that the former is a compound of nitrous-acid and phlo¬ 
gidon. By the oppofite party, it is luppofed to be a fub¬ 
dance entirely Ample, and one of the condiment parts of 
the nitrous acid. This opinion feems in part now to be 
entertained bv Dr. Priedley himfelf, aotwiihfianding his 
former lentiments on the fubjeCt. “ I had no doubt on 
S 1 this 
