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Siphon barometer
(gcide) | Siphon \Si"phon\, n. [F. siphon, L. sipho, -onis, fr. Gr. ??? a
siphon, tube, pipe.]
1. A device, consisting of a pipe or tube bent so as to form
two branches or legs of unequal length, by which a liquid
can be transferred to a lower level, as from one vessel to
another, over an intermediate elevation, by the action of
the pressure of the atmosphere in forcing the liquid up
the shorter branch of the pipe immersed in it, while the
continued excess of weight of the liquid in the longer
branch (when once filled) causes a continuous flow. The
flow takes place only when the discharging extremity of
the pipe ia lower than the higher liquid surface, and when
no part of the pipe is higher above the surface than the
same liquid will rise by atmospheric pressure; that is,
about 33 feet for water, and 30 inches for mercury, near
the sea level.
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2. (Zool.)
(a) One of the tubes or folds of the mantle border of a
bivalve or gastropod mollusk by which water is
conducted into the gill cavity. See Illust. under
Mya, and Lamellibranchiata.
(b) The anterior prolongation of the margin of any
gastropod shell for the protection of the soft siphon.
(c) The tubular organ through which water is ejected from
the gill cavity of a cephaloid. It serves as a
locomotive organ, by guiding and confining the jet of
water. Called also siphuncle. See Illust. under
Loligo, and Dibranchiata.
(d) The siphuncle of a cephalopod shell.
(e) The sucking proboscis of certain parasitic insects and
crustaceans.
(f) A sproutlike prolongation in front of the mouth of
many gephyreans.
(g) A tubular organ connected both with the esophagus and
the intestine of certain sea urchins and annelids.
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3. A siphon bottle.
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Inverted siphon, a tube bent like a siphon, but having the
branches turned upward; specifically (Hydraulic
Engineering), a pipe for conducting water beneath a
depressed place, as from one hill to another across an
intervening valley, following the depression of the
ground.
Siphon barometer. See under Barometer.
Siphon bottle, a bottle for holding aerated water, which is
driven out through a bent tube in the neck by the gas
within the bottle when a valve in the tube is opened; --
called also gazogene, and siphoid.
Siphon condenser, a condenser for a steam engine, in which
the vacuum is maintained by the downward flow of water
through a vertical pipe of great height.
Siphon cup, a cup with a siphon attached for carrying off
any liquid in it; specifically (Mach.), an oil cup in
which oil is carried over the edge of a tube in a cotton
wick, and so reaches the surface to be lubricated.
Siphon gauge. See under Gauge.
Siphon pump, a jet pump. See under Jet, n.
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Siphon barometer
(gcide) | Barometer \Ba*rom"e*ter\, n. [Gr. ba`ros weight + -meter: cf. F.
barom[`e]tre.]
An instrument for determining the weight or pressure of the
atmosphere, and hence for judging of the probable changes of
weather, or for ascertaining the height of any ascent.
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Note: The barometer was invented by Torricelli at Florence
about 1643. It is made in its simplest form by filling
a graduated glass tube about 34 inches long with
mercury and inverting it in a cup containing mercury.
The column of mercury in the tube descends until
balanced by the weight of the atmosphere, and its rise
or fall under varying conditions is a measure of the
change in the atmospheric pressure. At the sea level
its ordinary height is about 30 inches (760
millimeters). See Sympiesometer. --Nichol.
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Aneroid barometer. See Aneroid barometer, under
Aneroid.
Marine barometer, a barometer with tube contracted at
bottom to prevent rapid oscillations of the mercury, and
suspended in gimbals from an arm or support on shipboard.
Mountain barometer, a portable mercurial barometer with
tripod support, and long scale, for measuring heights.
Siphon barometer, a barometer having a tube bent like a
hook with the longer leg closed at the top. The height of
the mercury in the longer leg shows the pressure of the
atmosphere.
Wheel barometer, a barometer with recurved tube, and a
float, from which a cord passes over a pulley and moves an
index.
[1913 Webster] Barometric |
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