n. [ Gr.
☞ 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. [ 1913 Webster ]
Aneroid barometer.
Marine barometer,
Mountain barometer,
Siphon barometer,
Wheel barometer,
n. [ Hydro-, 1 + barometer. ] An instrument for determining the depth of the sea water by its pressure. [ 1913 Webster ]
n. [ Gr.
n. [ Thermo- + barometer. ]
(Physics) A barometer in which the changes of atmospheric pressure are indicated by the motion of a column of water instead of mercury. It requires a column of water about thirty-three feet in height. [ 1913 Webster ]