1. (Physics)
Defn: An instrument for determining the specific gravities of liquids, and thence the strength spirituous liquors, saline solutions, etc.
Note: It is usually made of glass with a graduated stem, and indicates the specific gravity of a liquid by the depth to which it sinks in it, the zero of the scale marking the depth to which it sinks in pure water. Extra weights are sometimes used to adapt the scale to liquids of different densities.
2. An instrument, variously constructed, used for measuring the velocity or discharge of water, as in rivers, from reservoirs, etc., and called by various specific names according to its construction or use, as tachometer, rheometer, hydrometer, pendulum, etc.; a current gauge.
HYDROMETRIC; HYDROMETRICAL
Hy`dro*met"ric, Hy`dro*met"ric*al, a. Etym: [Cf. F. hydromètrique.]
1. Of or pertaining to an hydrometer, or to the determination of the specific gravity of fluids.
2. Of or pertaining to measurement of the velocity, discharge, etc., of running water.
3. Made by means of an hydrometer; as, hydrometric observations. Hydrometric pendulum, a species of hydrometer consisting of a hollow ball of ivory or metal suspended by a treated from the center of a graduated quadrant, and held in a stream to measure the velocity of the water by the inclination given to the thread; a kind of current gauge.
HYDROMETROGRAPH
Hy`dro*met"ro*graph, n. Etym: [Hydro-, 1 + Gr. graph.]
Defn: An instrument for determining and recording the quantity of water discharged from a pipe, orifice, etc., in a given time.