IRII 



mov. 



m 



mart particularly ehwrsatarfoed by baring three stamens, th. anthers 

 of whloh are tamed outwards, and an inferior ovary. The genera 

 are numerous, and some not well defined ; they inhabit the temperate 

 parte of th. world in preference to the hottest, where they are 

 cooipar.tir.ly rare. The Irit and Croetu are representatives of the 



re of 



northern form of the orJer, a* (Xatlioliu and 

 the genera prevalent in the eouthern hemisphere. All 

 are eanVMotly omamental to deserve oultiration, and 

 many are of striking beauty. They are principally native* of the 

 Cape of flood Hope, or of the middle parts of North America and 

 Europe. A few only are found within the tropic*. Acrid, purgative, 

 and emrtl n properties are met with in nome planU of this order. 

 Some are fragrant and aromatic, others supply starch and materials 

 for dyeing. The position of the order is between ffirmodoraette and 

 It hu 53 genera and 650 species. [Ims.] 



IRIDF.A. 



IRIHINA 



IKIDIUM. iPLATliicit] 



IRIDOSMIXE. This name is given to a compound of the metals 

 Indium and Osmium, found in the platinum mines of Russia, South 

 America, and the East Indies. The crystals are hexagonal prisms of 

 a pale steel-gray. It occurs in flat grains. Their composition varies. 

 One variety contains rhodium. They are distinguished by the odour 

 of osmium. 



IRIS. [Eft] 



IRIS, a genus of Plants, the type of the natural order Iridacett. 

 It has a tubular perianth with a petaloid membranous limb, the 

 HUH lite of the sepals revolute, often bearded, those of the petals 

 erect and converging ; 3 stamens, concealed beneath the lobes of the 

 style ; the style 8-parted near the upper end with petaloid segments 

 overarching the anthers, and bearing a 2-lipped transverse stigma 

 below their ends; the capsule 3-oelled, bursting through the cells 

 into three valves, coriaceous, with numerous flat or round and 

 fleshy seeds. 



/. rtrtintor. Blue Flag, has sword-shaped striated leaves, sheathing 

 at the base, a stem 2 or 3 feet high, round on one side and acute on 

 the other, and bearing from 2 to 6 flowers. This plant is a native of 

 swamps and wet meadows in the United States. The rootetock has 

 a nauseous acrid taste. It sets as a cathartic, and its action is 

 attended with great depression of the nervous system and prostration 

 of strength. It also acte upon the kidneys, and is useful in cases 

 where diuretics are indicated. 



/. fmd-aeorut. Yellow Flag, baa sword-shaped leaves ; the item 

 round ; perianth beardless, ite inner segments narrower and shorter 

 than the stigmas. It is a native of wet places in Great Britain, 

 France. Germany, and most countries of Europe. The rootstock is 

 acrid, and possesses an emetic and purgative action. The seeds when 

 roasted are said to form a good substitute for coffee. 



/. tlomina. Florentine Iris, has broad and somewhat falcate 

 leaves, shorter than the stem, the petals two inches long and one inch 

 broad, reflexed at the edge and rather plaited towards the base. The 

 dried rootetock is known in the shops under the name of orris-root 

 The plant is a native of the southern parts of Europe and the 

 Mends of the Mediterranean. The rootetock has an aromatic odour 

 and subacrid taste, and is employed ss a dentifrice. It enters into 

 the composition of Ruspini's tincture and tooth-powder, and other 

 popular dentifrices. It waa at one time used in medicine and 



peas. According to Sibthorp this plant is found in Greece at the 

 present day. It is the V of Hippocrates (' Morb. Mul.,' 2, 673) and 

 th. V UAtpurk. of Tbeophrastus ( Hist Plant,' 7, 12). 



/. /vftrfiarmo. Stinking Fir*, has sword-shaped leaves, the stem 

 eoraprssesd. the perianth beardless, its inner segments about as long 

 as the stigmas. This plant is a native of Great Britain and other 

 parte of Europ*. It has a p.culiar smell, which some have compared 

 to roast beef, but which to others suggests much less pleasant asso- 

 ciations. It is the *l.it *ypa of Tbeophrastus (' Hist Plant,' 9, 8) 

 aod >Vt of Dioeoorldes (4, 12). 



/ r^rroM has tetragonal leaves, the segments of the perianth acute, 

 the roote tuberose. It is not a common plant in Europe, but has 

 bar. naturalised at Peiuanoe in Cornwall, and near Cork in Ireland. 



Many other species of trii have bern described. /. (krmmica has 

 beta need for the MUM purposes aa /. florrnKna, and they are 



by some botanist* M Identical The roote of many of 

 them contain starch, and Pallas says that the roote of /. afeJMMM 

 are eaten in Siberia. /. tdmlu Is eaten by the Hottentots of Africa, 

 wbere it is ealled Uenkjea. All tkese .pedes are cultivated in gardens 

 on account of hanitsnrns showy flowers. 



(Fis*s fyMfm f ent Game*.- Lindley. Plan italic*; Sibthorp, 

 Bsr. r, ; Habingtoo, if OHM! / OrilM Atfony; Burnett! 

 ^"asf e/ oofenjr.) 



ll(( "I*. Of all the metals iron is the most widely dimmed, the most 

 abuMhat, and the most useful It is found not only intermixed with 

 oils, and contained in rocks and mineral*, but it is found in animal 

 and vegetable bodim, and ). in mineral waters. 



Iron occurs rarely, if indeed at all, in nature in the metallic state, 



for almost the whole of it that has been found occurs as meteoric iron 

 containing nickel, or in meteoric stones. It has however been stated 

 that it has been discovered in situ near Canaan in the United States ; 

 it there occurs in a vein two inches thick in chlorite whist, fillud 

 with native iron. It appears that this iron is traversed by graphite. 

 Ite specific gravity is 51)5 to 671. The Uraliau Mountains yield a 

 kind of native iron which is accompanied with platinum. 



The greatest quantity of iron is found either combined with oxygen, 

 oxygen and carbonic acid, or with sulphur ; the last mentioned is not 

 however worked at an ore. The best iron-ore* are oxides, which 

 occur in primitive countries, where they generally form very large 

 beds, such as those of Sweden ; but the greater part of the iron-ore 

 of Britain is an impure carbonate. 



The properties of iron are, that it is grayish-white with a tint of 

 blue ; it is extremely ductile, so that it may be drawn into wire finer 

 than the human hair, but it cannot be beaten into very thin leaves. 

 It is of all metals the most tenacious, for a wire 0-787 of a line in 

 diameter is capable of supporting a weight of about 550 Ibs. 



Iron is susceptible of a high polish. It is combustible when 

 minutely divided, as in the state of filings, which is shown by sprinkling 

 them in the flame of a spirit lamp. It is very hard at common tem- 

 peratures, and this property may be increased by its being heated and 

 then suddenly cooled ; it then however becomes brittle. It requires 

 a most intense heat to melt it, but when heated to redness it becomes 

 soft and pliable, and possesses the valuable property of 'welding,' that 

 is, two pieces of red-hot iron may be made to unite by hammering. 

 Its texture is fibrous. Its specific gravity is about 777, but this 

 varies in tome degree according to the extent to which it has been 

 drawn, rolled, or hammered, and it is increased by fusion. Iron, or 

 rather steel, is capable of being rendered permanently magnetic, a 

 property which no other metal possesses but nickel : when heated to 

 redness this property is lost, nnd a loadstone suffers the same loss just 

 below visible ignition ; while a steel magnet loses its polarity when 

 subjected to the temperature of boiling almond-oil Iron has great 

 affinity for oxygen and sulphur, and some other elementary bodies, 

 and combines with them iu various proportions. 



Mtteoric /row. There have been found in different parts of the 

 earth large masses of native or metallic iron, of the history and origin 

 of which nothing very accurate ia known ; but they are regarded as 

 being of meteoric origin, for it is invariably found that, like the iron 

 which occurs in meteoric stones, this metallic iron contains nickel, and 

 no such compound or mixture is found iu the earth in veins or beds ; 

 and in point of fact two masses of such iron were seen to fall at 

 Hrad.-china, near Agrara in Croatia, iu 1751. They contained 35 per 

 cent of nickel. Similar masses have been found in Africa, America, 

 and Siberia. That in the last-mentioned port of the world was dis- 

 covered by Professor Pallas : it weighed 1600 lb*., had a cellular 

 structure, and contained crystals and grains of a green substance of a 

 vitreous appearance, which have been stated to be Olirine or Chrytolite. 

 This iron contains only 1-5 per cent of nickel. One of the largest 

 missus is that found in Peru by Don Kubin de Celis ; it weighed 15 

 tons, and contained nickel This was alo the case with the knives 

 which Captain Parry obtained from the Esquimaux. The largest 

 quantity of nickel contained iu any specimen was about 10 per cent 



Meteoric Iron sometimes occurs crystallised ; the primary form is 

 the cube, and it is stated to have been found in regular octahedrons. 

 It has no apparent cleavage. Fracture hackly. Hardness 4 -5. Specific 

 gravity 6-48 to 7768. Opaque. Lustre metallic. Colour pale steel-gray. 



Oxide* of Iron. The protoxide of iron does not occur iu nature 

 except in combination, and usually with carbonic acid; in this form 

 it is found in mineral waters. The ore which moat nearly approaches 

 it is Magnetic Iron, sometimes called Oxydulous Iron and Octohedral 

 Iron. This ore is found crystalline, massive, and arenaceous. The 

 crystals occur attached and imbedded. The primary form is a cube, 

 but it is generally met with in the form of the regular octohedron. 

 Cleavage parallel to the planes of the octohedron, but not obtainable 

 in some varieties. Fracture uneven or conchoidal Hardness 5-5 to 

 6-6. Scratches fluor-spar, and is scratched by quartz. Specific gravity 

 variously stated from 4'4 to 5*094. Opaque. Lustre metallic, occa- 

 sionally bright Colour iron- or steel-gray. Streak block. Obeys the 

 BBMBM ' 



The massive varieties are amorphous ; structure granular to com- 

 pact It is of this variety of iron-ore that native loadstones consist 

 This ore occurs in various parte of the world, especially in the north 

 of Europe, and it is of it that the best Swedish iron is made, and so 

 also ia the iron which yields the wootz steel of the Host Indies. It is 

 generally found in primitive countries. This ore frequently contains 

 titanium ; but the varieties have not been well distinguished. l!y the 

 blow-pi]>e it becomes brown, and loses its magnetic property, but does 

 not fuse. 



It consists of 28-4 of oxygen and 71 '6 of iron, which are equal to 

 Two equivalent* of Seiiquioxide of Iron . . 80 

 One equivalent of Protoxide of Iron . . . 36 



There are several ores, which possess very different appearances, 

 that are altogether composed of the sesquioxide or peroxide of iron, 

 and which are principally the Oligutc fnn On and the Hematite. 



<>i;</iii<c Iron ; tyrcM/ar or .Wicactoiu tron, This occurs crystallixoil 

 and massive. The crystals are attached ; the primary form in a 



