Source : Webster's Revised Unabridged Dictionary (1913)

Hydrometric \Hy`dro*met"ric\, Hydrometrical \Hy`dro*met"ric*al\,
   a. [Cf. F. hydrom[`e]trique.]
   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.