Hy*drom"e*ter (?), n. [Hydro-, 1
+ -meter: cf. F. hydromètre.] 1.
(Physics) An instrument for determining the specific
gravities of liquids, and thence the strength spirituous liquors,
saline solutions, etc.
&fist; 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.
