Origin of hydrometerhydro- + -meter
an instrument for measuring the specific gravity of liquids: it is a graduated, weighted tube that sinks in a liquid up to the point determined by the density of that liquid
An instrument used to determine specific gravity, especially a sealed, graduated tube, weighted at one end, that sinks in a fluid to a depth used as a measure of the fluid's specific gravity.
- hy′dro·met′ric hy′dro·met′ri·cal
An instrument used to measure the density of a liquid as compared to that of water. Hydrometers consist of a calibrated glass tube ending in a weighted glass sphere that makes the tube stand upright when placed in a liquid. The lower the density of the liquid, the deeper the tube sinks.
- 89) as follows: - Baume's Hydrometer for Spirits.
- The hydrometer is said by Synesius Cyreneus in his fifth letter to have been invented by Hypatia at Alexandria,' but appears to have been neglected until it was reinvented by Robert Boyle, whose "New Essay Instrument," as described in the Phil.
- C. 28, which established Sikes's hydrometer on a permanent footing.
- The quantity of alcohol present in an aqueous solution is determined by a comparison of its specific gravity with standard tables, or directly by the use of an alcoholometer, which is a hydrometer graduated so as to read per cents by weight (degrees according to Richter) or volume per cents (degrees according to Tralles).
- Acting on a principle quite different from any previously discussed is the capillary hydrometer or staktometer of Brewster, which is based upon the difference in the surface tension and density of pure water, and of mixtures of alcohol and water in varying proportions.