Gas (găs), n.; pl.
Gases (-ĕz). [Invented by the chemist Van
Helmont of Brussels, who died in 1644.] 1. An
aëriform fluid; -- a term used at first by chemists as
synonymous with air, but since restricted to fluids supposed
to be permanently elastic, as oxygen, hydrogen, etc., in distinction
from vapors, as steam, which become liquid on a reduction of
temperature. In present usage, since all of the supposed permanent
gases have been liquified by cold and pressure, the term has resumed
nearly its original signification, and is applied to any substance in
the elastic or aëriform state.
2. (Popular Usage) (a)
A complex mixture of gases, of which the most important
constituents are marsh gas, olefiant gas, and hydrogen, artificially
produced by the destructive distillation of gas coal, or sometimes of
peat, wood, oil, resin, etc. It gives a brilliant light when burned,
and is the common gas used for illuminating purposes.
(b) Laughing gas. (c)
Any irrespirable aëriform fluid.
☞ Gas is often used adjectively or in combination; as,
gas fitter or gasfitter; gas meter or
gas-meter, etc.
Air gas (Chem.), a kind of gas made
by forcing air through some volatile hydrocarbon, as the lighter
petroleums. The air is so saturated with combustible vapor as to be a
convenient illuminating and heating agent. -- Gas
battery (Elec.), a form of voltaic battery, in
which gases, especially hydrogen and oxygen, are the active
agents. -- Gas carbon, Gas
coke, etc. See under Carbon, Coke,
etc. -- Gas coal, a bituminous or
hydrogenous coal yielding a high percentage of volatile matters, and
therefore available for the manufacture of illuminating gas.
R. W. Raymond. -- Gas engine, an engine
in which the motion of the piston is produced by the combustion or
sudden production or expansion of gas; -- especially, an engine in
which an explosive mixture of gas and air is forced into the working
cylinder and ignited there by a gas flame or an electric spark.
-- Gas fitter, one who lays pipes and puts up
fixtures for gas. -- Gas fitting.
(a) The occupation of a gas fitter.
(b) pl. The appliances needed for the
introduction of gas into a building, as meters, pipes, burners,
etc. -- Gas fixture, a device for
conveying illuminating or combustible gas from the pipe to the gas-
burner, consisting of an appendage of cast, wrought, or drawn metal,
with tubes upon which the burners, keys, etc., are adjusted. --
Gas generator, an apparatus in which gas is
evolved; as: (a) a retort in which volatile
hydrocarbons are evolved by heat; (b) a
machine in which air is saturated with the vapor of liquid
hydrocarbon; a carburetor; (c) a machine for
the production of carbonic acid gas, for aërating water, bread,
etc. Knight. -- Gas jet, a flame of
illuminating gas. -- Gas machine, an
apparatus for carbureting air for use as illuminating gas. --
Gas meter, an instrument for recording the
quantity of gas consumed in a given time, at a particular place.
-- Gas retort, a retort which contains the coal
and other materials, and in which the gas is generated, in the
manufacture of gas. -- Gas stove, a stove
for cooking or other purposes, heated by gas. -- Gas
tar, coal tar. -- Gas trap,
a drain trap; a sewer trap. See 4th Trap, 5. --
Gas washer (Gas Works), an apparatus
within which gas from the condenser is brought in contact with a
falling stream of water, to precipitate the tar remaining in it.
Knight. -- Gas water, water through
which gas has been passed for purification; -- called also gas
liquor and ammoniacal water, and used for the manufacture
of sal ammoniac, carbonate of ammonia, and Prussian blue.
Tomlinson. -- Gas well, a deep boring,
from which natural gas is discharged. Raymond. --
Gas works, a manufactory of gas, with all the
machinery and appurtenances; a place where gas is generated for
lighting cities. -- Laughing gas. See
under Laughing. -- Marsh gas
(Chem.), a light, combustible, gaseous hydrocarbon,
CH4, produced artificially by the dry distillation of many
organic substances, and occurring as a natural product of
decomposition in stagnant pools, whence its name. It is an abundant
ingredient of ordinary illuminating gas, and is the first member of
the paraffin series. Called also methane, and in coal mines,
fire damp. -- Natural gas, gas
obtained from wells, etc., in Pennsylvania, Ohio, and elsewhere, and
largely used for fuel and illuminating purposes. It is chiefly
derived from the Coal Measures. -- Olefiant
gas (Chem.). See Ethylene. --
Water gas (Chem.), a kind of gas made by
forcing steam over glowing coals, whereby there results a mixture of
hydrogen and carbon monoxide. This gives a gas of intense heating
power, but destitute of light-giving properties, and which is charged
by passing through some volatile hydrocarbon, as gasoline.