iridian

[Latin iris, gen it. irid ( is )=the rainbow; Eng. adj. suff. -an.] Pertaining to the rainbow. ( Ann andale.) I-rid-1-0-, pref. [IRIDIUM.] (See the compound.) irilio-chlorides, s. pl. [IRIDIUM.] i-rid-I-o-scõpe, s. [Gr. iris (gen it. iridos ) =a rainbow, the iris, and skopeō to see, to observe.] An optical instrument which shows the inside of the eye, used to detect foreign substances and dis i-rid-1-ŭm, s . [ Gr.iris =the rainbow, and eidos = form, appearance.] 1. Chem.: A tetrad metallic element, symbol Ir.; atomic weight 198; discovered by Descotils in 1803, and by Tennant in 1804, in the black powder which remains when crude platinum is di olved in nitro hydrochloric acid. This powder is an alloy of irid ium and osmium, called iridosmine or osmiridium. To separate the iridium from the alloy, the black powder is mixed with an equal weight of dry sodium chloride, and heated to redne in a gla tube, through which a stream of moist chlorine gas is transmitted. The further end of the tube is connected with a ve el containing ammonia. Iridium chloride and osmium chloride are formed; the former remains in the tube in combination with the sodium chloride, while the latter, being a volatile substance, is carried forward into the receiver where it is decomposed into osmic and hydrochloric acids, which combine with the ammonia. The iridium and sodium chloride left in the tube is di olved in water, mixed with an exce of sodium carbonate and evaporated to dryne . The residue, after ignition in a crucible, is reduced by hydrogen at a high temperature, and treated succe ively with water and concentrated hydrochloric acid, by which all impurities are removed, and the metallic iridium left in a finely divided state. Iridium is a white, brittle, very hard metal, fusible with great difficulty, in the flame of the oxy-hydrogen blowpipe. It is insoluble in all acids, but when reduced by hydrogen at a red heat it oxidizes slowly and di olves in nitro-hydrochloric acid. Iridium forms four oxides -IrO. Ir2O3, Ir02, and IrO3. The monoxide, or hypo-iridious oxide, Ir0, is but little known. The sesquioxide, or iridious oxide, Ir2O3, is unstable, having a great tendency to absorb oxygen and become dioxide. The dioxide, or iridic oxide, IrO2 is the most easily prepared and the most stable. It is prepared by boiling a solution of iridic chloride with an alkali. The trioxide, or per iridic oxide, IrO3, is unknown in the free state, but is found in combination with potash as a black crystalline powder, when iridium is fused with niter. Iridium forms four chlorides-IrCl, IrC12, Ir2C16, and IrClbut only two of them have been obtained in definite form-viz., the trichloride, or iridious chloride, Ir2Cl6, and the tetrachloride, or iridic chloride, Ir. Iridious chloride combines with other metallic chlorides, forming compounds, called iridosochlorides, which are all olive-green pulverulent 1. Anat .: The colored portion of the eye surrounding the black central pupil. It consists of three of pigment called the uvea, and a middle fibrous layer. 2. Bot . The typical genus of the order Iridaceae (q. v.). The perianth is 16gular, its segments unequal; sepals large, stipulate, reflexed; petals smaller, sub-erect, stipulate; stigmas three, very broad, petaloid. About forty-eight are known, all from the north temperate zone. The roasted seeds of I. pseud a cor us are like coffee. It is a diuretic purgative and emetic, as are I. tuberosa, I. versicolor , and I. verna. I. flor ent in a furnishes the violet-scented orris-root, which is slightly stimulating. It is used in the preparation of the sweet-scented otto of roses. I. ensata has been supposed to furnish the iris a root of India. Dr. Stewart says that it is used externally in the treatment of rheumatism. In Chumba the root and leaves are given in fever. The purple flowers of I. germanic a and I. sibirica , treated with lime, furnish a green color, I. sibirica is anti-syphilitic; I. fœtidi ima is said to be a cure for scrofula. The Peacock Iris is the genus Vieu euxia, the Scorpion Iris I. alata , and the Snake's-head Iris I. tuberosa , or Hermodactylus tuberosus . The name iris is given to the genus because of the variety and beauty of the colors in the flowers. 3. Astron .: [ASTEROID, 7.] iris-diaphragm, 8. IMG:content-0044.png:[blocks in formation] Bot. & Comm.: The same as ORRIS-ROOT (q. v.). I'-ris-at-ěd, a. [Eng. iris ; -ated.] Exhibiting the prismatic colors; resembling the rainbow. I'-ri-scope, 8. [Gr. iris =the rainbow, and skopeō = to behold.] Mach.: An instrument invented by Dr. Reade for exhibiting the prismatic colors. It consists of a plate of polished black gla , having its surface smeared with a solution of soap, and dried by wash-leather. If the breath be directed through a tube upon the gla , the vapor will be deposited in colored rays. I'-rised, a . [Eng. iris; -ed.] Containing colors like those of the rainbow. Ir-Ish, a. & 8. [A. S. yrisc.] A. As adjective : 1. Pertaining to Ireland or its inhabitants; like an Irish man. 2. Pertaining to the Highlands of Scotland. [ERSE.] B. As substantive: Irish-elm, 8. iron Bot.: Ulmus montana nigra. Irish famine-fever, s. [FAMINE-FEVER. Irish-furze, s . Bot.: Ulex strict us. Irish-heath, s. Bot.: Menziesia polifolia. Irish-mo , s. [CARAGHEEN.] Irish Presbyterian Church, 8. Ecclesiol. & Ch . Hist .: A Presbyterian Church, formerly called the Synod of Ulster, as having its mainly within that province of Ireland. Its members are mostly descended from the Scotch Presbyterians, who came over by invitation of James I., between 1609 and 1612, to colonize Ulster. (IRISH SOCIETY.] The Church still remains ident i cal in doctrine with the Scottish Establishment. Irish Society, 8. English Hist .: A committee of citizens belonging to twelve London Companies, invited by James I. in 1613 to take part in cultivating the confiscated lands in Ulster, which, to the extent of 511,465 acres, had become vested in the Crown. The society in large measure built London derry, though walls and bastions had been erected there as early as 1609. They largely colonized the county of the same name, which was bestowed in honor of the twelve London companies. The full title of the society is the Honorable Irish Society. Irish-whin, s. [IRISH-FURZE.] Ir-Ish-Ism, s. [Eng. Irish; -ism.] A mode of expre ion or idiom peculiar to the Irish; an iricism. Ir'-Ish-man, s. [Eng. Irish . and man .] A native or naturalized inhabitant of Ireland. Ir-Ish-ry, 8. [Eng. Irish ; -ry.] The people of Ireland, as opposed to the English settlers, known as the Englishry. "Choosing rather to trust the winds and waves than the exasperated Irishry ." -Macaulay : Hist . Eng . , ch. xii. ir-ite, s . [Lat. iris Gr.iris =the rainbow; suff. ite ( Min .) (q. v.).] Min .: A variety of Chromate (q. v.). I-ri-tis, i-rid-1'-tis, s . [Gr. iris (gen it. iridos); suff.- it is (q. v.).] Path .: Inflammation of the iris, accompanied by vascularity, change in color and appearance, irregularity and immobility of the pupil, with a visible and varying amount of lymph deposited in, on, and round the iris. *Irk, *irk-en, *yrke, *irk-yn, v. t. & i. [Sw. yrka to urge, to pre , from the same root as work and urge .] A. Trans.: To tire; to weary; to be irksome or wearisome to. (Now only used impersonally.) B. In trans.: To grow or become tired or weary. Irk'-some, *yrke-some, a . [Eng. irk; -some.] 1. Wearisome, tiring, tedious; tiresome by long continuance or repetition. *2. Sorrowful, sad, weary. *3. Weary; tired. Îrk'-some-lỹ, *Irk-som-ly, adv . [Eng. irksome; ly.] In an irksome, tedious, wearisome or tiresome manner. Irk-some-ne , *yrke-som-ne e, s. [English irksome; -ne .] The quality or state of being irksome; tediousne , wearisomene . iron (as i-ern), *iren, *yren, *yrene, *yron, *yrun, *yzen, s . & a . [A. S., as subst., tren, ýren, isen, irsern, as adj., tren, ýren, isen, isern; O. S. isarn; O. H. Ger. isarn , is an, isen; M. H. Ger. tsen; N. H. Ger. eisen; Dut. ysen; Goth. eisarn; Icel. jarn ; Dan. & Sw. jern ; Ir. iarran , earran , iarun ; Gael., as subst., iaruinn , iaruach , as adj., iaruinn , iaruach; Wel. haiarn ; Arm. houarn .] IMG:content-0045.jpg:[graphic] IMG:content-0046.png:[blocks in formation] 2. The Irish language. *3. An old game resembling backgammon. Irish Church, s. [CHURCH OF IRELAND.] Irish-elk, s. [ELK.) chin, bench; go, gem; thin, this; iron ironstone. The ore is first calcined, to expel the water and carbonic acid and most of the sulphur, and to convert the oxides to peroxide, which prevents the waste of iron in the form of slag. The calcined ore is then smelted, with the addition of coke and limestone; the limestone unites with the silica present and forms a fusible slag, while the oxide of iron is reduced by the action of the carbon monoxide. [BLAST-FURNACE.] The iron thus obtained is called cast or pig iron, and is very impure. Puro iron is prepared by placing four parts of fine iron wire, cut in pieces, and one part of black oxide of iron in a He ian crucible, and covering it with a mixture of white sand, lime, and pota ium carbonate in the proportions used for gla -making; a cover is then closely applied and the crucible exposed to a very high temperature. Iron is a soft, tough, tenacious, malleable, ductile, white metal, not acted upon by dry air; but it rusts in moist air containing carbonic acid, forming a hydrate of the sesquioxide. When heated to redne in the air, it is coated with black magnetic oxide, Fe3O4. It burns in oxygen gas, black oxide being formed. Red-hot iron decomposes water, hydrogen being given off. Iron is magnetic; it is soluble in dilute hydrochloric acid and in dilute sulphuric acid with evolution of hydrogen. Iron unites with oxygen, forming ferrous oxide FeO and ferric oxide Fe2O3. Intermediate oxides are also known. The salts of iron have already been described. The alchemists represented it by the symbol of Mars &. [FERROUS, FERRIC, WROUGHT-IRON, STEEL.] 3. Geol.: Iron is widely diffused through the rocks. Many are colored red by its oxides It is also deposited from ferruginous springs. [IRON ORE; BOG IRON-ORE.] 4. Hist .: Iron is mentioned in the Bible as early as Gen. iv. 22. Tubal Cain is described as having been an "instructor of every artificer in bra (copper) and iron." On the sepulchers of the Egyptian Thebes, butchers are depicted as sharpening their knives on a round bar of metal which, from being blue, is a umed to be iron. The steel weapons in the time of Rameses III. are also painted blue. There are with them the representations of bronze weapons, which are painted red. [IRON AGE (2).] Iron ore is said to have been discovered in Mount Ida about B. C. 1406. The Romans early knew it. There is so much iron ore in India that it must have been known from remote times. Iron mines came into operation in Britain B. C. 54. The exportation of iron was prohibited by the British Government in 1354, and in 1483 the importation of such manufactured iron goods as could be made at home was forbidden. In 1713 Darby introduced the general use of coal instead of wood as fuel, a proce which had been practiced by Lord Dudley in 1619. In 1783 Cort obtained a patent for rolling, and in 1784 for puddling iron. The hot blast was discovered by Dalton in in 1827, and the Be emer proce for converting crude iron into manufactured iron and steel in 1856. 5. Min .: Native iron is found in ma es or smaller portions in meteorites. It is nearly pure, still it contains one to twenty per cent. of nickel with traces of cobalt, manganese, tin, copper, chromium, phosphorus, . Whether unmeteoric native iron exists is doubtful. Specimens of ore so pure as to admit of direct forging into horseshoes have been mined at Shepherd's Mountain, in the Iron Mountain district of Mi ouri. [METEORITE.] 6. Pharm .: In the hematin or coloring matter of the blood 64 per cent. is iron. When anemia осcurs, the administration of iron is of much use. It acts also on the nervous system. It often, however, causes constipation, and sometimes also stains the tongue and the teeth. It may be given in the form of reduced iron lozenges, saccharine carbonate of iron, compound mixture of iron, a pill of carbonate of iron, iodide of iron, . (1) Iron Alum = Halo trichite; Iron and Man ganese Tungstate Wolfram; Iron Antimonial Sulphuret = Berthierite; Iron Apatite = Zwieselite; Iron Arsenate= (1) Pharma cos ide rite, (2) Scorodite Iron Arsenide = Lõlingite; Iron Borate = Ludwig. ite or Lagonite; Iron Carbonate = Chalybite or Siderite; Iron Chromate Chromite; Iron Gymnite = Hydrophite; Iron Magnetic Oxide = Magnetite; Iron Phosphate=(1) Vivianite, (2) Ludlamite; Iron Pyrites = Pyrites, or Pyrite (q. v.); Iron Sesquioxide = (1) Hæmatite, (2) Göthite, (3) Limonite, (4) Turgite; Iron Silicate Lievrite; Iron Sinter Pitticite; Iron Sulphate Melanterite; Iron Sulphide = (1) Pyrites, (2) Marcasite, (3) Pyrrhotite; Iron Tungstate Wolfram; Iron Vitriol Melanterite. (2) Carburet of Iron = Graphite; Chloride of Iron Moly site; Columbate of Iron = Tantalite; Cupreous Arsenate or Arseniate of Iron=Scorodite; Diarsenate of Iron = Pitta cite; Magnetic Iron-ore =Magnetite; Meteoric or Native Iron [II. 5]; Olagist Iron Hæmatite; Oxalate of Iron Humboldtine; Oxide of Iron Hematite; Oxydulated Iron= Magnetite; Iron Sulphate=Melanterite; Tantalate of Iron Tantalite; Titaniferous Iron = Men acc a nite. IMG:content-0047.png:[blocks in formation] 1. Cla . Mythol .: The last of the four great ages of the world described by Hesiod, Ovid, . It was supposed to be characterized by abounding oppre ion, vice, and misery.