hydrometer (hi-drom'et-er)

An instrument for measuring the density, etc., of fluids. Baume's h. See under Bourne, h. of constant volume. A h. in which, like Nicholson's h. and Fahrenheit's h., the stem is always immersed to the same extent, while the load which the h. carries varies in each case and by the amount of its variation indicates the specific gravity, h. of con which stantthe weight. A h., such load remains as Baume's, constant in and the amount to which the stem is immersed varies, the amount of the variation indicating the specific gravity sought, h. of variable volume. See h. of constant weight, h. of variable weight. See h. of constant volume. Nicholson's h. See ynder Nicholson, [Gr., ydor, water, -f metron, a measure.]