[f. Gr. κάθετο-ς CATHETUS + -METER. Cf. F. cathétomètre.] An instrument for measuring vertical distances, esp. small differences of level of liquid columns in tubes.
1864. in Webster.
1871. B. Stewart, Heat, § 63. The difference of level between the surface of mercury in the two tubes was read by means of a cathetometer.
1879. Thomson & Tait, Nat. Phil., I. I. § 429. The Cathetometer is used for the accurate determination of differences of level.
