2. (Chem.) A metallic element mostly obtained by reduction
from cinnabar, one of its ores. It is a heavy, opaque,
glistening liquid (commonly called {quicksilver}), and is
used in barometers, thermometers, ect. Specific gravity
13.6. Symbol Hg (Hydrargyrum). Atomic weight 199.8.
Mercury has a molecule which consists of only one atom. It
was named by the alchemists after the god Mercury, and
designated by his symbol, [mercury].
Note: Mercury forms alloys, called amalgams, with many
metals, and is thus used in applying tin foil to the
backs of mirrors, and in extracting gold and silver
from their ores. It is poisonous, and is used in
medicine in the free state as in blue pill, and in its
compounds as calomel, corrosive sublimate, etc. It is
the only metal which is liquid at ordinary
temperatures, and it solidifies at about -39[deg]
Centigrade to a soft, malleable, ductile metal.
3. (Astron.) One of the planets of the solar system, being
the one nearest the sun, from which its mean distance is
about 36,000,000 miles. Its period is 88 days, and its
diameter 3,000 miles.
4. A carrier of tidings; a newsboy; a messenger; hence, also,
a newspaper. --Sir J. Stephen. ``The monthly Mercuries.''
--Macaulay.
5. Sprightly or mercurial quality; spirit; mutability;
fickleness. [Obs.]
He was so full of mercury that he could not fix long
in any friendship, or to any design. --Bp. Burnet.
6. (Bot.) A plant ({Mercurialis annua}), of the Spurge
family, the leaves of which are sometimes used for
spinach, in Europe.
Note: The name is also applied, in the United States, to
certain climbing plants, some of which are poisonous to
the skin, esp. to the {Rhus Toxicodendron}, or poison
ivy.
{Dog's mercury} (Bot.), {Mercurialis perennis}, a perennial
plant differing from {M. annua} by having the leaves
sessile.
{English mercury} (Bot.), a kind of goosefoot formerly used
as a pot herb; -- called {Good King Henry}.
{Horn mercury} (Min.), a mineral chloride of mercury, having
a semitranslucent, hornlike appearance.
{Quicksilver horizon}, a mercurial artificial horizon. See
under {Horizon}.
{Quicksilver water}, a solution of mercury nitrate used in
artificial silvering; quick water.