A barometer employing mercury in it vertical column, which is used to measure atmospheric pressure. Mercury barometers may be classified according to their construction into three groups: cistern barometers, siphon barometers, and weight barometers.
Type of barometer that measures changes in atmospheric pressure by the height of a column of mercury in a U-shaped tube which has one end sealed and the other end immersed in an open container of mercury. The force of the pressure exerted by the atmosphere on the mercury in the open container pushes mercury up the other end of the tube. The height of this level is then used as a measure of atmospheric pressure relative to the surface level of the mercury in the container.
a mercury-filled glass tube in which the height of the mercury column is a measure of air pressure. Russian translation prepared by Nina A. Zaitseva for the Arctic Climatology Project Arctic Meteorology and Climate Atlas.
(Or mercurial barometer; formerly called Torricelli's tube.) A glass manometer, employing mercury in its vertical column, that is used to measure atmospheric pressure. The basic construction, unchanged since Torricelli's experiment in 1643, is a glass tube about three feet long, closed at one end, filled with mercury, and inverted with the open end immersed in a cistern of mercury. With the cistern surface exposed to atmospheric pressure, the height of the mercury column varies with that pressure. Mercury barometers may be classified into three groups according to their construction: cistern barometers, siphon barometers, and weight barometers. See also aneroid barometer, inch of mercury.