GAS. 
alumina, zircon, and yttria. Some of the 
German ehemists have classed it as an acid, 
by the name of the hydrothian. 
The waters called sulphureous, or hepa- 
tic, as those of Harrowgale, are solutions 
of this gas. They are recommended as 
alteratives in cutaneous affections; against 
worms, in gout and jaundice, and as deob- 
struents; but they are said to have been 
very injurious in dropsy. 
Gas, muriatic acid. Muriatic acid exists 
in a separate state only in the form of gas, 
but its attraction for water is so strong, 
that it can be received and confined only 
over mercury. According to Kirwau, 
water absorbs rather more than 420 times 
its bulk, and is augmented by it about one 
third : in Dr. Thomson’s experiments it took 
up 515 times its bulk at 60° Fahrenheit. It 
liquifies ice very rapidly, and the tempera- 
ture is lowered. It has a pungent smell, 
is fatal to animals, and extinguishes flame, 
first imparting to it a greenish tinge. Its 
bulk is increased by a succession of electric 
shocks, which Mr. Henry has shewn to 
arise from the decomposition of water, of 
which he infers from his experiments 60 
grains hold 1.4 in solutions. On its coming 
into contact with atmospheric air, a white 
cloud is produced. Brisson gives its spe- 
cific gravity, atmospheric air being 1000, at 
1430, Henry at 1730, Kirwan at 1929. For 
its other properties see Muriatic Acid, 
Gas, oxygenized muriatic acid. This gas, 
which is a compound of the preceding with 
oxygen, presents another anomaly in the 
theory of acidification; it was observed, 
that sulphuretted hydrogen resembles an 
acid in many of its properties, though it 
contains no oxygen ; and we here find the 
radical of an acid, which with a certain pro- 
portion of oxygen ranks among the most 
powerful, so much weakened in its proper- 
ties, as even to be denied by some a place 
among the acids. 
This gas is not invisible, as it has a green- 
ish yellow colour. It has a pungent, suffo- 
cating smell, and is very injurious to the lungs ; 
it extinguishes burning bodies ; a tempera- 
ture of 40° Fahrenheit reduces it to a liquid 
form. Mr. Northmore condensed nearly 
two pints in a receiver of the capacity of 
2i inches, in which state it was a yellow 
fluid, so extremely volatile as to evaporate 
the instant the screw of the receiver was 
opened. A pint of this gas being injected 
upon half a pint of oxygen, the result was 
a thicker substance, that did not evaporate 
so soon, and left a yellowish mass behind. 
Nitrogen in the same proportion gave a still 
thicker substance, and of a deeper yellow. 
In both these experiments much of the 
grease of the machine was carried down. 
Into a receiver, of three inches capacity, 
a pint of carbonic acid gas was pumped, 
and then rather more than a pint of oxy- 
genized muriatic acid gas : the result was 
of a sap green colour, but still elastic. Two 
pints of the gas with a pint of hydrogen was 
of a light yellow green, without any fluid, 
and highly destructive of colours. 
This gas acts powerfully on various com- 
bustible bodies. If four parts of it, and 
three of hydrogen be put into a bottle 
closely stopped, inverted, with its mouth 
under water, and the stopple be taken out 
in this situation after they have thus stood 
twenty-four hours, nearly the whole of the 
gas will have disappeared, and the remain- 
der will be absorbed by the water. The 
hydrogen may be combined at once with 
the oxygen of this gas by the electric spark, 
which causes them to detonate. Phos- 
phorus takes fire spontaneously in oxygeniz- 
ed muriatic acid gas ; so do perfectly dry 
powdered charcoal of beech wood, and 
almost all the metals in fine filings, or 
very thin leaves. About a cubic inch of 
the gas, is sufficient for a grain of metal ; 
the bottom of the vessel should have a little 
sand on it, to prevent it from cracking; 
and the temperature should not be less 
than 70°. If a drachm of good ether be 
thrown into a three pint vessel filled with 
this gas, and the mouth covered with a 
piece of paper, a circulating white vapour 
will arise in a few seconds, which will soon 
be followed by an explosion with flame. 
For the rest of its properties see Muria- 
tic OXYGENIZED ACID. NlTRIC ACID GAS, 
and Nitric acid. 
Gas, nitric oxide, or nitrous gas. We 
owe our first knowledge of this elastic 
fluid to Dr. Priestley, who called it nitrous 
air. It may be formed by passing ammo- 
niacal gas through the black oxide of man- 
ganese heated red hot in an earthern tube; 
but it is most easily obtained by abstract- 
ing a portion of its oxygen trom nitric acid. 
For this purpose fine copper wire, or cop- 
per filings, may be put into a retort, with an 
equal weight of nitric acid, diluted with four 
or five parts of water, and moderate heat ap- 
plied ; or diluted only with an equal quan- 
tity of water, and no heat employed. After 
the atmospheric air is expelled from the 
retort, the gas that comes over may be re- 
ceived in the pneumatic apparatus. Other 
