Chapter 760

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.

Hydrometric, Hydrometrical <Xpage=717>

Hy`dro*met"ric (?) , Hy`dro*met"ric*al (?) , a. [Cf. F. hydrom\'8atrique .] 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.

Hydrometrograph <Xpage=717>

Hy`dro*met"ro*graph (?) , n. [ Hydro- , 1 + Gr. <?/ measure + - graph .] An instrument for determining and recording the quantity of water discharged from a pipe, orifice, etc., in a given time.

Hydrometry <Xpage=717>

Hy*drom"e*try (?) , n. [Cf. F. hydrom\'8atrique .] 1. The art of determining the specific gravity of liquids, and thence the strength of spirituous liquors, saline solutions, etc.

2. The art or operation of measuring the velocity or discharge of running water, as in rivers, etc.

Hydromica <Xpage=717>

Hy`dro*mi"ca (?) , n. [ Hydro- , 1 + mica .] (Min.) A variety of potash mica containing water. It is less elastic than ordinary muscovite.

Hydromica schist (Min.) , a mica schist characterized by the presence of hydromica. It often has a silky luster and almost soapy feel.

Hydronephrosis <Xpage=717>

Hy`dro*ne*phro"sis (?) , n. [NL., Gr. "y`dwr water + <?/ a kidney.] (Med.) An accumulation of urine in the pelvis of the kidney, occasioned by obstruction in the urinary passages.

Hydropath <Xpage=717>

Hy"dro*path (?) , n. [Cf. F. hydropathe .] A hydropathist.

Hydropathic, Hydropathical <Xpage=717>

Hy`dro*path"ic (?) , Hy`dro*path"ic*al (?) , a. Of or pertaining to hydropathy.

Hydropathist <Xpage=717>

Hy*drop"a*thist (?) , n. One who practices hydropathy; a water-cure doctor.

Hydropathy <Xpage=717>

Hy*drop"a*thy (?) , n. [ Hydro- , 1 + Gr. <?/, <?/, to suffer.] The water cure; a mode of treating diseases by the copious and frequent use of pure water, both internally and externally.

Hydroperitoneum <Xpage=717>

Hy`dro*per`i*to*ne"um (?) , n. [NL. See Hydro- , and Peritoneum .] (Med.) Same as Ascites .

Hydrophane <Xpage=717>

Hy"dro*phane (?) , n. [ Hydro- , 1 + Gr. <?/ to show, appear: cf. F. hydrophane .] (Min.) A semitranslucent variety of opal that becomes translucent or transparent on immersion in water.

Hydrophanous <Xpage=717>

Hy*droph"a*nous (?) , a. (Min.) Made transparent by immersion in water.

Hydrophid <Xpage=717>

Hy"dro*phid (?) , n. [ Hydro- , 1 + Gr. <?/ a small serpent.] (Zo\'94l.) Any sea snake of the genus Hydrophys and allied genera. These snakes are venomous, live upon fishes, and have a flattened tail for swimming.

Hydrophlorone <Xpage=717>

Hy`dro*phlo"rone (?) , n. [ Hydro- , 2 + phlorone .] (Chem.) A white, crystalline benzene derivative, C8H10O2 , obtained by the reduction of phlorone.

Hydrophobia <Xpage=717>

Hy`dro*pho"bi*a (?) , n. [L., fr. Gr. <?/; "y`dwr water + <?/ fear: cf. F. hydrophobie .] (Med.) (a) An abnormal dread of water, said to be a symptom of canine madness; hence: (b) The disease caused by a bite form, or inoculation with the saliva of, a rabid creature, of which the chief symptoms are, a sense of dryness and construction in the throat, causing difficulty in deglutition, and a marked heightening of reflex excitability, producing convulsions whenever the patient attempts to swallow, or is disturbed in any way, as by the sight or sound of water; rabies; canine madness. [Written also hydrophoby .]

Hydrophobic <Xpage=717>

Hy`dro*phob"ic (?) , a. [L. hydrophobicus , Gr. <?/: cf. F. hydrophobique .] Of or pertaining to hydrophobia; producing or caused by rabies; as, hydrophobic symptoms; the hydrophobic poison.

Hydrophoby <Xpage=717>

Hy"dro*pho`by (?) , n. See Hydrophobia .

Hydrophora <Xpage=717>

Hy*droph"o*ra (?) , n. pl. [NL., fr. E. hydra + Gr. <?/ to bear.] (Zo\'94l.) The Hydroidea.

Hydrophore <Xpage=717>

Hy"dro*phore (?) , n. [Gr. "y`dwr water + <?/ to bear.] An instrument used for the purpose of obtaining specimens of water from any desired depth, as in a river, a lake, or the ocean.

Hydrophyllium <Xpage=717>

Hy`dro*phyl"li*um (?) , n. ; pl. L. Hydrophyllia (#) , E. Hydrophylliums (#) . [NL., fr. Gr. "y`dwr water + <?/ a leaf.] (Zo\'94l.) One of the flat, leaflike, protective zooids, covering other zooids of certain Siphonophora.

Hydrophyte <Xpage=717>

Hy"dro*phyte (?) , n. [Gr. <?/ + <?/ plant: cf. F. hydrophyte .] An aquatic plant; an alga.

Hydrophytology <Xpage=717>

Hy*droph`y*tol"o*gy (?) , n. [ Hydro- + phyte + - logy .] The branch of botany which treats of water plants.

Hydropic, Hydropical <Xpage=717>

Hy*drop"ic (?) , Hy*drop"ic*al (?) , a. [L. hydropicus , Gr. <?/: cf. F. hydropique . See Dropsy .] Dropsical, or resembling dropsy.

Every lust is a kind of hydropic distemper, and the more we drink the more we shall thirst. Tillotson.

Hydropically <Xpage=717>

Hy*drop"ic*al*ly , adv. In a hydropical manner.

Hydropiper <Xpage=717>

Hy"dro*pi`per (?) , n. [NL., fr. Gr. "y`dwr water + L. piper a pepper.] (Bot.) A species ( Polygonum Hydropiper ) of knotweed with acrid foliage; water pepper; smartweed.

Hydropneumatic <Xpage=717>

Hy`dro*pneu*mat"ic (?) , a. [ Hydro- , 1 + pneumatic : cf. F. hydropneumatique .] Pertaining to, or depending upon, both liquid and gaseous substances; as, hydropneumatic apparatus for collecting gases over water or other liquids .

Hydropsy <Xpage=717>

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

Hydropult <Xpage=717>

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.

Hydroquinone <Xpage=717>

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 .

Hydrorhiza <Xpage=717>

Hy`dro*rhi"za (?) , n. ; pl. L. Hydrorhiz\'91 (#) , E. Hydrorhizas (#) . [NL., fr. E. hydra + Gr. <?/ a root.] (Zo\'94l.) The rootstock or decumbent stem by which a hydroid is attached to other objects. See Illust . under Hydroidea .

Hydrosalt <Xpage=717>

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.

<page="718"> Page 718

Hydroscope <Xpage=718>

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.

Hydrosome, Hydrosoma <Xpage=718>

Hy"dro*some (?) , Hy`dro*so"ma (?) , n. [NL. hydrosoma . See Hydra , and -some body.] (Zo\'94l.) All the zooids of a hydroid colony collectively, including the nutritive and reproductive zooids, and often other kinds.

Hydrosorbic <Xpage=718>

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 .

Hydrostat <Xpage=718>

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

Hydrostatic, Hydrostatical <Xpage=718>

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.

Hydrostatically <Xpage=718>

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

Bentley.

Hydrostatician <Xpage=718>

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

Hydrostatics <Xpage=718>

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.

Hydrosulphate <Xpage=718>

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

Hydrosulphide <Xpage=718>

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.

Hydrosulphite <Xpage=718>

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

Hydrosulphuret <Xpage=718>

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

Hydrosulphureted <Xpage=718>

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

Hydrosulphuric <Xpage=718>

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 .

Hydrosulphurous <Xpage=718>

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 .

Hydrotellurate <Xpage=718>

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

Hydrotelluric <Xpage=718>

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

Hydrotheca <Xpage=718>

Hy`dro*the"ca (?) , n. ; pl. L. Hydrothec\'91 (#) , E. Hydrothecas (#) . [NL., fr. E. hydra + Gr. <?/ a box.] (Zo\'94l.) One of the calicles which, in some Hydroidea (Thecaphora), protect the hydrants. See Illust . of Hydroidea , and Campanularian .

Hydrotherapy <Xpage=718>

Hy`dro*ther"a*py (?) , n. [ Hydro- , 1 + therapy .] (Med.) See Hydropathy .

Hydrothermal <Xpage=718>

Hy`dro*ther"mal (?) , a. [ Hydro- , 1 + thermal .] Of or pertaining to hot water; -- used esp. with reference to the action of heated waters in dissolving, redepositing, and otherwise producing mineral changes within the crust of the globe.

Hydrothorax <Xpage=718>

Hy`dro*tho"rax (?) , n. [ Hydro- , 1 + thorax .] (Med.) An accumulation of serous fluid in the cavity of the chest.

Hydrotic <Xpage=718>

Hy*drot"ic (?) , a. [Gr. "y`dwr water: cf. Gr. <?/ moisture, F. hydrotique .] Causing a discharge of water or phlegm. -- n. (Med.) A hydrotic medicine.

Hydrotical <Xpage=718>

Hy*drot"ic*al (?) , a. Hydrotic.

Hydrotrope <Xpage=718>

Hy"dro*trope (?) , n. [ Hydro- , 1 + Gr. <?/ to turn, direct.] A device for raising water by the direct action of steam; a pulsometer.

Hydrotropic <Xpage=718>

Hy`dro*trop"ic (?) , a. [See Hydrotrope .] (Bot.) Turning or bending towards moisture, as roots.

Hydrotropism <Xpage=718>

Hy*drot"ro*pism (?) , n. (Bot.) A tendency towards moisture.

Hydrous <Xpage=718>

Hy"drous (?) , a. [Gr. "y`dwr water.] 1. Containing water; watery.

2. (Chem.) Containing water of hydration or crystallization.

Hydroxanthane <Xpage=718>

Hy`dro*xan"thane (?) , n. (Chem.) A persulphocyanate. [Obs.]

Hydroxanthic <Xpage=718>

Hy`dro*xan"thic (?) , a. [ Hydro- , 2 + xanthic .] (Chem.) Persulphocyanic.

Hydroxide <Xpage=718>

Hy*drox"ide (?) , n. [ Hydro- , 2 + oxide .] (Chem.) A hydrate; a substance containing hydrogen and oxygen, made by combining water with an oxide, and yielding water by elimination. The hydroxides are regarded as compounds of hydroxyl, united usually with basic element or radical; as, calcium hydroxide ethyl hydroxide .

Hydroxy- <Xpage=718>

Hy*drox"y- (?) . (Chem.) A combining form, also used adjectively, indicating hydroxyl as an ingredient.

Hydroxy acid (Chem.) , an organic acid, having (besides the hydroxyl group of the carboxyl radical) an alcoholic hydroxyl group, and thus having the qualities of an alcohol in addition to its acid properties; as, lactic and tartaric acids are hydroxy acids.

Hydroxyl <Xpage=718>

Hy*drox"yl (?) , n. [ Hydro- , 2 + ox ygen + - yl .] (Chem.) A compound radical, or unsaturated group, HO , consisting of one atom of hydrogen and one of oxygen. It is a characteristic part of the hydrates, the alcohols, the oxygen acids, etc.

Hydroxylamine <Xpage=718>

Hy*drox`yl*am"ine (?) , n. [ Hydroxyl + amine .] (Chem.) A nitrogenous, organic base, NH2.OH , resembling ammonia, and produced by a modified reduction of nitric acid. It is usually obtained as a volatile, unstable solution in water. It acts as a strong reducing agent.

Hydrozoa <Xpage=718>

Hy`dro*zo"a (?) , n. pl. [NL., fr. E. hydra + Gr. <?/ an animal.] (Zo\'94l.) The Acaleph\'91; one of the classes of c\'d2lenterates, including the Hydroidea, Discophora, and Siphonophora.

Hydrozoal <Xpage=718>

Hy`dro*zo"al (?) , a. (Zo\'94l.) Of or pertaining to the Hydrozoa.

Hydrozo\'94n <Xpage=718>

Hy`dro*zo"\'94n (?) , n. ; pl. L. Hydrozoa (#) , E. Hydrozo\'94ns (#) . [NL.] (Zo\'94l.) One of the Hydrozoa.

Hydruret <Xpage=718>

Hy"dru*ret (?) , n. [ Hydro- , 2] (Chem.) A binary compound of hydrogen; a hydride. [Obs.]

Hydrus <Xpage=718>

Hy"drus (?) , n. [L., a water serpent; also, a certain constellation, Gr. "y`dros .] (Astron.) A constellation of the southern hemisphere, near the south pole.

Hye <Xpage=718>

Hye (?) , n. & v. See Hie . [Obs.]

Chaucer.

Hyemal <Xpage=718>

Hy*e"mal (?) , a. [L. hyemalis , or better hiemalis , fr. hyems , hiems , winter: cf. F. hy\'82mal .] Belonging to winter; done in winter.

Sir T. Browne.

Hyemate <Xpage=718>

Hy"e*mate (?) , v. i. [L. hiemare , hiematum . See Hyemal .] To pass the winter. [Obs. & R.]

Hyemation <Xpage=718>

Hy`e*ma"tion (?) , n. [L. hiematio .] 1. The passing of a winter in a particular place; a wintering.

2. The act of affording shelter in winter. [Obs.]

Hyen <Xpage=718>

Hy"en (?) , n. [F. hy\'8ane .] A hyena. [Obs.]

Shak.

Hyena <Xpage=718>

Hy*e"na (?) , n. ; pl. Hyenas (#) . [L. hyaena , Gr. <?/, orig., a sow, but usually, a Libyan wild beast, prob., the hyena, fr. <?/ hog: cf. F. hy\'8ane . See Sow female hog.] (Zo\'94l.) Any carnivorous mammal of the family Hy\'91nid\'91 , of which three living species are known. They are large and strong, but cowardly. They feed chiefly on carrion, and are nocturnal in their habits. [Written also hy\'91na .]

&hand; The striped hyena ( Hy\'91na striata ) inhabits Southern Asia and a large part of Africa. The brown hyena ( H. brunnea ), and the spotted hyena ( Crocuta maculata ), are found in Southern Africa. The extinct cave hyena ( H. spel\'91a ) inhabited England and France.

Cave hyena . See under Cave . -- Hyena dog (Zo\'94l.) , a South African canine animal ( Lycaon venaticus ), which hunts in packs, chiefly at night. It is smaller than the common wolf, with very large, erect ears, and a bushy tail. Its color is reddish or yellowish brown, blotched with black and white. Called also hunting dog .

Hyetal <Xpage=718>