manometer

Ma*nom"e*ter, n. Etym: [Gr. -meter: cf. F. manomètre.] Defn: An instrument for measuring the tension or elastic force of gases, steam, etc., constructed usually on the principle of allowing the gas to exert its elastic force in raising a column of mercury in an open tube, or in compressing a portion of air or other gas in a closed tube with mercury or other liquid intervening, or in bending a metallic or other spring so as to set in motion an index; a pressure gauge. See Pressure, and Illust. of Air pump.

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