mercury barometer


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Related to mercury barometer: aneroid barometer

mercury barometer

[′mər·kyə·rē bə′räm·əd·ər]
(engineering)
An instrument which determines atmospheric pressure by measuring the height of a column of mercury which the atmosphere will support; the mercury is in a glass tube closed at one end and placed, open end down, in a well of mercury. Also known as Torricellian barometer.

mercury barometer

mercury barometer
An absolute pressure gauge specifically designed to measure atmosphere pressure and its change. It consists of a long, hollow glass tube from which air is evacuated. It is placed upside down in a cistern filled with mercury. The pressure of the outside air forces the mercury in the cistern upward into the vacuum chamber. This rise in the level of mercury is dependent on the prevalent atmospheric pressure. The absolute atmospheric pressure can be read off the tube by suitably calibrating it.
References in periodicals archive ?
One of the most charming mercury barometers was named after Admiral Robert FitzRoy (1805-1865), the head of the Meteorological Office of the oard of Trade.
In addition, if required for the instrument, operators should record barometric pressure taken from both the instrument and an independent mercury barometer.
He was known to have performed an experiment comparing the performance of the new aneroid barometer supplied by Negretti and Zambra against that of the mercury barometer.
The changes in the atmospheric pressure are a good indicator of weather patterns and mercury barometers were first used to measure pressure as early as the mid 17th Century.