Hydra

hi'dra, n. E. pi. -dras, -draz, L. pi. -dr.b, -dre. (Myth.) A water-serpent having many heads, one of which, being cut off, was succeeded by another, unle the wound was cauterized. A multifarious evil, or one not to be repre ed by a single effort. (Zool.) A minute kind of fresh water polyp. [L. Gr. hudra, water-snake, Gr. hudor, hudatos, water L. und a, Skr. udan, Goth, wato, D. and E. water, q. v.] — Hy'drous, -drus, a. Containing water, watery. — Hydremia, -dre'mY-a, n. (Pathol.) An abnormally watery state of the blood. [Gr. hudor and haima, blood.]— Hydran^gea, -je-a, n. (Bot.) A shrubby genus of plants bearing opposite leaves and large heads of showy flowers. [Gr. anggeion, ve el, capsule.] — Hydrant, n. A pipe or spout at which water may be drawn from the mains of an aqueduct a water-plug street fountain. — Hydrar'gyrum, -jT-rum, n. Quicksilver mercury. [Gr. arguros, silver.] — Hy'drate, -drat, n. Chem.) A compound formed by the union of a definite proportion of water with some other substance, generally forming a neutral salt. — Hy'dride, -drid n. (Chem.) A compound of the binary type, in which hydrogen, as a negative, united with some other element. — Hydrau'lic, -drawlik, -lical, a. Pert, to hydraulics, or to fluids in motion. — Hydraulics, sing. That branch of science or of engineering which treats of fluids, esp. water, in motion. [F. hydraulique, music of running water, Gr. hudraulis, an organ worked by water, aulos, a tube, pipe.] Hydravrlie cement. Cement which — will harden under water. H. pre . A pre in which great power obtained a forcing pump which forces water into a large cylinder. — ram. A machine for raising water by means of the momentum of the water of which a portion to be Hydraulic Ram. raised.— Hy'droceie, n. (Med.) Dropsy of the scrotum or of the coverings of — the testicles or spermatic cord. [Gr. kele, tumor.] Hydrocephalus, -sefa-lus, n. (Med.) Dropsy of the brain. [Gr. kephale, head.] — Hy'drodynamlc, a. Pert, to, or derived from, the force or pre ure of water. — Hy drodynam,ics, n. Principles of dynamics, as applied to water and other fluids.—Hy drofluor -floo-oVik, a. (Chem.) Pert, to, or derived from, fluorine and hydrogen, —if. acid. An acid obtained by distilling fluor-spar with sulphuric acid. — Hy'- drogen, -jen, n. (Chem.) An inflammable, colorle , inodorous gas of extreme lightne , — one of the elements of water. [Gr. gene in, to generate, — the combustion of hydrogen producing water.] — Hy'drogenate, -at, v. (Chem.) To combine with hydrogen.— Hy'drogenize, v. [-ized (-izd), -izing.J To combine with hydrogen, hydrogenate. — Hydrog''- enous, -droj'e-nus, a. Pert, to, or containing, hydrogen. — Hydrog 'rapher, -fer, n. One who draws maps of the sea, etc., with the adjacent shores. Odd, tone, 6r 287 HYEMAL 269 Hydroglaphy, -ft, Art of measuring and describing the sea, lakes, rivers, etc., or of forming charts of the same. [Gr. gi'aphein, to draw, describe.]— Hydrol'ogy, Science of water, properties, phenomena, and laws, distribution in lakes, rivers, etc., over the earth's surface. [Gr. logos, discourse.]— Hy'droman'cy, -man'sT, n. Divination or prediction of events by water. [Gr. manteia, divination.] — Hy'dromel. -drc-mel, n. A liquor consisting of honey diluted in water. [Gr. mel i, honey.] — Hydrom''eter, An instrument for determining the specific gravities and thence the strength of liquids; also, one for measuring the velocity or discharge of water, as in rivers, from reservoirs, etc. [Gr. metron, measure.] — Hydromet'ric, -rical, a. Pert, to hydrometry or made by a hydrometer. — Hydrom'etry, -trf, n. The determining the specific gravity and strength of liquids; art or operation of measuring the velocity or discharge of running water.— Hydrop'athy, -a-tht, The water cure, a mode of treating diseases by the use of pure water. £Gr. pathos, suffering.] — Hydropathic, -ical, a. Pert, to, etc.— Hydrop >at hi8t, Hy'dropath, n. One who practices, etc.— Hydropho"'bia, -fo'M-a, {Med.) A preternatural dread of water, — a symptom of canine madne ; the disease caused by inoculation with the saliva of a rabid dog. [Gr. phobos, fear.] — Hydrophobic, a. Pert, to, etc. — Hydrop'ic. -ical, a. Dropsical; resembling dropsy. — Hy'dropult, n. A machine for throwing water Dy hand power, — a garden engine, fire extinguisher, etc. [Gr. pallein, to hurl.] — Hy'droscope, -skop, An instrument to mark the presence of water in air; a kind of water clock used by the ancients. [Gr. skopein, to view.] —Hydrostatic, -ical, a. Relating to liydrostatics; pert, to, or in accordance with, the principles of the equilibrium of fluids. — Hydrostatics, Science of the pre ure and equilibrium of fluids. [See Statics.] — Hydrotholax, (Med.) Dropsy in the chest. [Gr. thorax, chest.]