Part 955

Hy"drop`sy (?), n. Same as Dropsy.

Hy"dro*pult (?), n. [Hydro-, 1 + Gr. &?; to hurl.] A machine for throwing water by hand power, as a garden engine, a fire extinguisher, etc.

Hy`dro*qui"none (?), n. [Hydro-, 2 + quinone.] (Chem.) A white crystalline substance, C6H4(OH)2, obtained by the reduction of quinone. It is a diacid phenol, resembling, and metameric with, pyrocatechin and resorcin. Called also dihydroxy benzene.

||Hy`dro*rhi"za (?), n.; pl. L. HydrorhizÊ (#), E. Hydrorhizas (#). ||[NL., fr. E. hydra + Gr. &?; a root.] (Zoˆl.) The rootstock or ||decumbent stem by which a hydroid is attached to other objects. See ||Illust. under Hydroidea.

Hy"dro*salt` (?), n. [Hydro-, 1 + salt.] (Chem.) (a) A salt supposed to be formed by a hydracid and a base. (b) An acid salt. [R.] (c) A hydrous salt; a salt combined with water of hydration or crystallization.

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Hy"dro*scope (?), n. [Hydro-, 1 + -scope.] 1. An instrument designed to mark the presence of water, especially in air. Weale.

2. A kind of water clock, used anciently for measuring time, the water tricking from an orifice at the end of a graduated tube.

{ Hy"dro*some (?), ||Hy`dro*so"ma (?) }, n. [NL. hydrosoma. See Hydra, and -some body.] (Zoˆl.) All the zooids of a hydroid colony collectively, including the nutritive and reproductive zooids, and often other kinds.

Hy`dro*sor"bic (?), a. [Hydro-, 2 + sorbic.] (Chem.) Pertaining to, or designating, an acid obtained from sorbic acid when this takes up hydrogen; as, hydrosorbic acid.

Hy"dro*stat (?), n. A contrivance or apparatus to prevent the explosion of steam boilers.

{ Hy`dro*stat"ic (?), Hy`dro*stat"ic*al (?), } a. [Hydro-, 1 + Gr. &?; causing to stand: cf. F. hydrostatique. See Static.] Of or relating to hydrostatics; pertaining to, or in accordance with, the principles of the equilibrium of fluids.

The first discovery made in hydrostatics since the time of Archimedes is due to Stevinus.

Hallam.

Hydrostatic balance, a balance for weighing substances in water, for the purpose of ascertaining their specific gravities. -- Hydrostatic bed, a water bed. -- Hydrostatic bellows, an apparatus consisting of a water-tight bellowslike case with a long, upright tube, into which water may be poured to illustrate the hydrostatic paradox. -- Hydrostatic paradox, the proposition in hydrostatics that any quantity of water, however small, may be made to counterbalance any weight, however great; or the law of the equality of pressure of fluids in all directions. -- Hydrostatic press, a machine in which great force, with slow motion, is communicated to a large plunger by means of water forced into the cylinder in which it moves, by a forcing pump of small diameter, to which the power is applied, the principle involved being the same as in the hydrostatic bellows. Also called hydraulic press, and Bramah press. In the illustration, a is a pump with a small plunger b, which forces the water into the cylinder c, thus driving upward the large plunder d, which performs the reduced work, such as compressing cotton bales, etc.

Hy`dro*stat"ic*al*ly, adv. According to hydrostatics, or to hydrostatic principles. Bentley.

Hy`dro*sta*ti"cian (?), n. One who is versed or skilled in hydrostatics. [R.]

Hy`dro*stat"ics (?), n. [Cf. F. hydrostatique.] (Physics) The branch of science which relates to the pressure and equilibrium of nonelastic fluids, as water, mercury, etc.; the principles of statics applied to water and other liquids.

Hy`dro*sul"phate (?), n. (Chem.) Same as Hydrosulphurent.

Hy`dro*sul"phide (?), n. (Chem.) One of a series of compounds, derived from hydrogen sulphide by the replacement of half its hydrogen by a base or basic radical; as, potassium hydrosulphide, KSH. The hydrosulphides are analogous to the hydrates and include the mercaptans.

Hy`dro*sul"phite (?), n. (Chem.) A saline compound of hydrosulphurous acid and a base. [R.]

Hy`dro*sul"phu*ret (?), n. (Chem.) A hydrosulphide. [Archaic]

Hy`dro*sul"phu*ret`ed (?), a. (Chem.) Combined with hydrogen sulphide.

Hy`dro*sul*phu"ric (?), a. [Hydro- , 2 + sulphuric.] (Chem.) Pertaining to, or derived from, hydrogen and sulphur; as, hydrosulphuric acid, a designation applied to the solution of hydrogen sulphide in water.

Hy`dro*sul"phur*ous (?), a. (Chem.) Pertaining to, or designating, an acid obtained by the reduction of sulphurous acid. See Hyposulphurous acid, under Hyposulphurous.

Hy`dro*tel"lu*rate (?), n. (Chem.) A salt formed by the union of hydrotelluric acid and the base.

Hy`dro*tel*lu"ric (?), a. [Hydro- , 2 + telluric.] (Chem.) Formed by hydrogen and tellurium; as, hydrotelluric acid, or hydrogen telluride.

||Hy`dro*the"ca (?), n.; pl. L. HydrothecÊ (#), E. Hydrothecas (#). ||[NL., fr. E. hydra + Gr. &?; a box.] (Zoˆl.) One of the calicles ||which, in some Hydroidea (Thecaphora), protect the hydrants. See ||Illust. of Hydroidea, and Campanularian.