Hydrant, hī′drant, n. a machine for discharging water: a water-plug. [Gr. hydōr, water.]
Hydrate, hī′drāt, n. a compound formed by the union of water with an oxide.—n. Hydrā′tion. [Gr. hydōr, water.]
Hydraulic, -al, hī-drawl′ik, -al, adj. relating to hydraulics: conveying water: worked by water.—adv. Hydraul′ically.—n.pl. Hydraul′ics, used as sing., the science of hydrodynamics in its practical application to water-pipes, &c.—Hydraulic belt, an arrangement for lifting water, consisting of an endless belt fitted with buckets which discharge as they turn over an upper wheel; Hydraulic cement, lime, a cement that sets or hardens under water; Hydraulic jack, a jack or lifting apparatus, by means of oil, &c., pressed by a force-pump against a piston or plunger; Hydraulic mining, a method of mining by which the auriferous detritus is washed down by a powerful jet of water into a sluice where the gold is easily separated; Hydraulic press, a press operated by the differential pressure of water on pistons of different dimensions; Hydraulic ram, an automatic pump worked by the pressure of a column of water in a pipe, and the force acquired by intermittent motion of the column. [From Gr. hydōr, water, aulos, a pipe.]
Hydria, hī′dri-a, n. a large Greek water-vase.—n. Hy′driad, a water-nymph.
Hydrid, hī′drid, n. (chem.) a substance consisting of hydrogen combined with an element or some compound radical.—n. Hy′driodate, a salt of hydriodic acid.—adj. Hydriod′ic, produced by the combination of hydrogen and iodine.
Hydrobarometer, hī-dro-ba-rom′e-ter, n. an instrument for determining the depth of the sea by the pressure of the superincumbent water.
Hydrobromic, hī-dro-brō′mik, adj. compounded of bromine and hydrogen.—n. Hydrobrō′mate, a salt of hydrobromic acid—same as bromide; also Bromhydrate.
Hydrocarbon, hī-dro-kär′bon, n. a compound of hydrogen and carbon.—Hydrocarbon furnace, a furnace in which liquid fuel, as petroleum, is used.
Hydrocele, hī′dro-sēl, n. (med.) a swelling consisting of a collection of serous fluid in the scrotum or in some of the coverings of the testicle or spermatic cord. [Gr. hydōr, water, kēlē, a swelling.]
Hydrocephalus, hī-dro-sef′a-lus, n. an accumulation of serous fluid within the cranial cavity, either in the sub-dural space or the ventricles: water in the head: dropsy of the brain.—adjs. Hydrocephal′ic, Hydroceph′aloid, Hydroceph′alous. [Gr. hydōr, water, kephalē, the head.]