Part 5467

<hw>Hy"dra*zine</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[<ets>Hydr-</ets> + <ets>azo-</ets> + -<ets>ine</ets>.]</ety> <fld>(Chem.)</fld> <def>Any one of a series of nitrogenous bases, resembling the amines and produced by the reduction of certain nitroso and diazo compounds; <as>as, methyl <ex>hydrazine</ex>, phenyl <ex>hydrazine</ex>, etc.</as> They are derivatives of hydrazine proper, <chform>H2N.NH2</chform>, which is a doubled amido group, recently (1887) isolated as a stable, colorless gas, with a peculiar, irritating odor. As a base it forms distinct salts. Called also <altname>diamide</altname>, <altname>amidogen</altname>, (or more properly <altname>diamidogen</altname>), etc.</def>

<h1>Hydrencephsloid</h1> <Xpage=716>

<hw>Hy"dren*ceph"s*loid</hw> <tt>(?)</tt>, <tt>a.</tt> <ety>[<ets>Hydrencephal</ets>us + -<ets>oid</ets>.]</ety> <fld>(Med.)</fld> <def>Same as <er>Hydrocephaloid</er>.</def>

<h1>Hydria</h1> <Xpage=716>

<hw>Hy"dri*a</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[L., fr. Gr. <?/.]</ety> <fld>(Gr. Antiq.)</fld> <def>A water jar; esp., one with a large rounded body, a small neck, and three handles. Some of the most beautiful Greek vases are of this form.</def>

<h1>Hydriad</h1> <Xpage=716>

<hw>Hy"dri*ad</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Gr. <?/, <?/, of the water, fr. <grk>"y`dwr</grk> water.]</ety> <fld>(Myth.)</fld> <def>A water nymph.</def>

<h1>Hydric</h1> <Xpage=716>

<hw>Hy"dric</hw> <tt>(?)</tt>, <tt>a.</tt> <ety>[From <er>Hydrogen</er>.]</ety> <fld>(Chem.)</fld> <def>Pertaining to, or containing, hydrogen; <as>as, <ex>hydric</ex> oxide</as>.</def>

<cs><col>Hydric dioxide</col>. <fld>(Chem.)</fld> <cd>See <cref>Hydrogen dioxide</cref>, under <er>Hydrogen</er>.</cd> -- <col>Hydric oxide</col> <fld>(Chem.)</fld>, <cd>water.</cd> -- <col>Hydric sulphate</col> <fld>(Chem.)</fld>, <cd>hydrogen sulphate or sulphuric acid.</cd></cs>

<h1>Hydride</h1> <Xpage=716>

<hw>Hy"dride</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[<ets>Hydr-</ets> + <ets>ide</ets>.]</ety> <fld>(Chem.)</fld> <def>A compound of the binary type, in which hydrogen is united with some other element.</def><-- spec., with a more electropositive element -->

<-- lithium hydride. A hydride of lithium, LiH, commonly used as a powerful reducing agent in organic chemistry -->

<h1>Hydriform</h1> <Xpage=716>

<hw>Hy"dri*form</hw> <tt>(?)</tt>, <tt>a.</tt> <ety>[<ets>Hydra</ets> + -<ets>form</ets>.]</ety> <fld>(Zo\'94l.)</fld> <def>Having the form or structure of a hydra.</def>

<h1>Hydrina</h1> <Xpage=716>

<hw>Hy*dri"na</hw> <tt>(?)</tt>, <tt>n. pl.</tt> <ety>[NL. See <er>Hydra</er>.]</ety> <fld>(Zo\'94l.)</fld> <def>The group of hydroids to which the fresh-water hydras belong.</def>

<h1>Hydriodate</h1> <Xpage=716>

<hw>Hy*dri"o*date</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Cf. F. <ets>hydriodate</ets>.]</ety> <fld>(Zo\'94l.)</fld> <def>Same as <er>Hydriodide</er>.</def>

<h1>Hydriodic</h1> <Xpage=716>

<hw>Hy`dri*od"ic</hw> <tt>(?)</tt>, <tt>a.</tt> <ety>[<ets>Hydr-</ets> + <ets>iodic</ets>: cf. F. <ets>hydriodique</ets>.]</ety> <fld>(Chem.)</fld> <def>Pertaining to, or derived from, hydrogen and iodine; -- said of an acid produced by the combination of these elements.</def>

<cs><col>Hydriodic acid</col> <fld>(Chem.)</fld>, <cd>a pungent, colorless gas, <chform>HI</chform>, usually prepared as a solution in water. It is strong reducing agent. Called also <altname>hydrogen iodine</altname>.</cd></cs>

<h1>Hydriodide</h1> <Xpage=716>

<hw>Hy*dri"o*dide</hw> <tt>(?)</tt>, <tt>n.</tt> <fld>(Chem.)</fld> <def>A compound of hydriodic acid with a base; -- distinguished from an <i>iodide</i>, in which only the iodine combines with the base.</def>

<h1>Hydro-, Hydr-</h1> <Xpage=716>

<hw><hw>Hy"dro-</hw> <tt>(?)</tt>, <hw>Hy"dr-</hw>.<hw> <p><b>1.</b> <def>A combining form from Gr. <?/, <?/, water (see <er>Hydra</er>).</def>

<p><b>2.</b> <fld>(Chem.)</fld> <def>A combining form of <i>hydrogen</i>, indicating <i>hydrogen as an ingredient</i>, <as>as <ex>hydro</ex>chloric; or a <ex>reduction product obtained by hydrogen</ex>, as <ex>hydro</ex>quinone.</as></def>

<h1>Hydrobarometer</h1> <Xpage=716>