from the GNU version of the Collaborative International Dictionary of English
- n. an instrument for measuring the pressure of steam, as in a boiler.
- n. an instrument for indicating the pressure of the steam in a boiler. The mercurial steam gauge is a bent tube partially filled with mercury, one end of which is connected with the boiler while the other is open to the air, so that the steam by its pressure raises the mercury in the long limb of the tube to a height proportioned to that pressure. A more common form, especially for high pressures, consists of a spring pressed upon by the steam, and connected with the pointer of a dial. The spring may be a flattened, bent tube, closed at one end, which the entering steam tends to straighten, or it may be a diaphragm of elastic metal, or a mass of confined air, etc.
Sorry, no etymologies found.