OXOPI1YLLUM, in botany, a genus of the monadelpliiapentandria class and order. Natural order, TrihilaUe. Styleone; calyx five-toothed ; petals five, long; lilamenls sheathingthe style, live-toothed at top; teeth anthorilerous; stigma one;capsule five-celled. There is but one species, O. feetidmn, ashrub of Guiana.
OX-TONGUE, in botany. See Picris.
OXUS, or Jill-UN, a large river of Asia , much taken noticeof in ancient histories; it runs a course of about ‘260 miles from theCaspian sea to the lake Aral.
OXYCHATE, ?, from ofv; and ximw,] in pharmacy, a
mixture of water and vinegar, used to assuage, cool, and re Ire A.The usual proportion is one spoonful of vinegar to live or sixspoonfuls of water.
OXYDATION, the process by which bodies are convertedinto oxides, particularly applied to the combining of oxygen andmetallic substances. 'I he process of oxydation is effected morerapidly when metals are exposed to the 'action of heat; and, in-deed, many metals require a very high temperature to producethe combination, while it cannot be accomplished in others by thegreatest degree of heat that can be produced. This process wasformerly called calcination, or calcining the metal; and the pro-duct, now denominated an oxide, was distinguished by the nameof calx or calces, from its being reduced to Ihe state of powder, inthe same way as limestone, by burning. Metals differ very muchfrom each other ill the circumstances ill which this oxydation takesplace, as in the temperature which is necessary, the facility of thecombination,-the propoitions of oxygen which combine, and theforce of ai. ,ity between the constituent parts of the oxide. Somemetals are oxydated in the lowest temperature, as, for instance,iron and manganese ; while others require the greatest degree ofbeat that can be applied. Such are silver, gold, and platina.During the process of oxydation, metals are divested of their lus-tre; and, after increasing considerably in weight, they exhibit anearthy appearance. Chemists, from this circumstance, have longconjectured, that all earths are metallic oxides, and that they are ailausceplible of reduction to a metallic slate, provided there be anymatter for which oxygen lias more powerful elective attractionthan that by which it is kept in combination with the bases of theoxides. 1 his lias been in part verified by the experiments ofDr. Daw. - 1
OXYfJRAC.T., an ancient warlike nation of India , who confe-derated with the Calheri and Malli, against the invasion of Alex-ander the Great : but were defeated.
OXYGEN, [from of-j;, acid, and ymaw, to produce,] in che-mistry, a substance which constitutes the base of oxygen gas, and■which enters into combination with several substances' formingthose classes of bodies called acids and oxides. See Chemistry.Oxygen is considered as one of the elements incapable of decom-'position; nor will it admit of being exhibited by itself, or ofbeing produced in its simple state : for, at the moment of its lie-coming free, it unites with the light, and caloric, or heat of thesurrounding medium, and thus forms what lias been severally de-'nominated vital air, tire-air, deplilogisticated, or pure air, andlastly, ox)gen-gas. See Gas. The peculiar character of thiselastic fluid was lirst developed by Dr. Priestley, whose experi-ments have been confirmed, and the properties of gas-oxygenfully explained, by Lavoisier , Cavendish, and oilier illustriouschemical philosophers. From their discoveries it appears, thattliis uncompounded invisible matter can be known only in its com-binations; tipat it forms a constituent part of the atmo-pheric air,in which it exists in the proportion of 27 or 2S parts to 100. Far-ther, oxygen may lie separated not only from the atmosphere, butal»o from water; from all acids; and also from vegetables exposedto tlie rays of the sun. By this natural process, a considerablePortion of it is evolved from the leaves of plants during their per-spiration, in consequence of solar heat: thus, when oxygen is car-ried to their roots, by means of the circulating fluids, it is be-lieved to promote their growth ; though, if it lie absorbed too co-piously, and rapidly, it is unfavourable to vegetation. On thecontrary, a very large proportion is requisite to conduce to thegrowth, and to nourish the vitality of animals. So universallydiffused is this substance, that it is supposed to exist in all bodies,whether ol the vegetable, animal, or mineral, kingdoms, and par-ticularly ill certain metallic calces or oxides; such as ruddle, ca-
lamine, burnt clay, Ac. which, on account of the large quantityof the acidifying principle they contain, are conjectured to be ofconsiderable utility as manures. For the method of obtaining theoxygen gas, see Gas ; and for the affinities of oxygen, see Che-mistry.
OXYGENATE, to combine 1 'any substance with oxygen.
OXYGENATED, combined with oxygen.
Oxygenated Muriatic Acid. See Muriatic .
OXYGENATION, the combination of an acid with oxygen.
OXYGLYCU, a species of drink, prepared of the sw etesthoney-combs macerated and boiled. The combs, from which altthe honey lias been expressed, are put into a pot with pure water,and boiled till they seem to have deposited all their containedhoney in the water. This liquor is to be kept, and when dilutedwith cold water, is to be drank in the summer-time, in order toremove thirst.
OXYGON IOUS, [from »fv;, sharp, and yamx, an angle,] ingeometry, acute-angied.
OXY .MEL, [o*a,«tXi, ofv,-, and/*Du,] in pharmacy, a mixture ofhoney and vinegar, which are boiled to the consistence of a syrup.See Pharmacy.
OXYMORON , [»|:<fAw;n, Gr.] a rhetorical figure, in whichan epithet of a quite contrary signification is added to any word.See Oratory.
OXY-MUE1 ATE, a salt formed by the combination of theoxy-inuriatic acid, with different bases. “ Though the oxy-muriatic acid was discovered,” (says Dr. Thomson,) by Scheele ,it was not till 1786, that Berthollet discovered the possibility ofcombining it with different bases, and forming that class of saltsnow named oxy-muriates. These salts cannot be formed by dis-solving tlie different liases in the acid, while liquid, in conse-quence, perhaps of the strong affinity it has for water; but maybe easily formed by tlie following process: Dissolve tlie basewhich is to be combined with tlie acid, or its carbonate, in w r ater,or mix it with water if it be insoluble, and putting it into one ofWoulfe’s bottles, cause oxy-inunalic acid, in tlie state of gas, dis-tilled in tlie usual manner, to puss through it. The acid combineswith tlie base, and (if a carbonate lie used) an effervescence takesplace, owing to the disengagement of tlie carbonic acid gas. Astlie base becomes saturated with acid, tlie oxy-muriate graduallyprecipitates in the state of crystals. At the same time with tlieoxy-muriate a quantity of common muriate is formed ; but it maybe'easily separated by dissolving tlie salt in a small quantity ofboiling water, and allowing it to cool; tlie greater part of the oxy-nniriates fall down in crystals, whereas tlie other salt remains insolution. Tlie oxy-muriates may be distinguished by the follow-ing properties: I.'When heated moderately they give out a greatquantity of oxygen gas, and are converted into common muriates.2. When mixed with combustibles, they detonate with muchgreater violence than tlie nitrates. This detonation is occasionednot only by heal, but by friction and percussion, and often takesplace spontaneously. 3. Soluble in water, ami capable of crystal-lizing when tlie solution cools. Tlie greater number of themhave been but slightly examined; owing probably t,o tlie difficultyof forming them rapidly. Some of them, however, have been in-troduced into tlie process of bleaching, with much advantage.
OXY-MUKIAT1C ACID, an acid composed of muriatic acidand oxygen. It is also called oxygenated muriatic acid. SeeMuriatic Acid , Oxygenated.
OXYRF.GM1A, in medicine, a sourness of the stomach, occa-sioning acid belches.
OXY R KIIODINE, [ofvjeoiivav, ofv;, and a mixture oftwo parts of oil of roses with one of vinegar ot roses.
OXYTOCHA, [from ofvj, sharp, and tixtw, to bring forth,]in midwifery, medicines given to promote delivery.
OYER, layer, old Fr. to hear,] a court of oyer and termineris a judicature where causes are heard and determined. Thisword, in law-books, seems to have been anciently used-for what itnow called assises. See Assise.
OY ES, [oyec, Fr. hear ye,] is the introduction to any procla-mation, or advertisement given by the public criers, both in Eng-land and Scotland . It is thrice repeated. It is also frequentlyused by the criers in our courts, on making proclamation, or toenjoin silence. "
OYSTER, in zoology. See Ostrea.
Oysters,