LIMONITE

limonite, or brown iron ore, a natural ferric hydrate named from the gr. [greek: leimon] (meadow), in allusion to its occurrence as "bog-ore" in meadows and marshes. it is never crystallized, but may have a fibrous or microcrystalline structure, and commonly occurs in concretionary forms or in compact and earthy masses; sometimes mammillated, botryoidal, reniform or stalactitic. the colour presents various shades of brown and yellow, and the streak is always brownish, a character which distinguishes it from haematite with a red, or from magnetite with a black streak. it is sometimes called brown haematite. limonite is a ferric hydrate, conforming typically with the formula fe4o3(oh)6, or 2fe2o3·3h2o. its hardness is rather above 5, and its specific gravity varies from 3.5 to 4. in many cases it has been formed from other iron oxides, like haematite and magnetite, or by the alteration of pyrites or chalybite. by the operation of meteoric agencies, iron pyrites readily pass into limonite often with retention of external form; and the masses of "gozzan" or "gossan" on the outcrop of certain mineral-veins consist of rusty iron ore formed in this way, and associated with cellular quartz. many deposits of limonite have been found, on being worked, to pass downwards into ferrous carbonate; and crystals of chalybite converted superficially into limonite are well known. minerals, like glauconite, which contain ferrous silicate, may in like manner yield limonite, on weathering. the ferric hydrate is also readily deposited from ferruginous waters, often by means of organic agencies. deposits of brown iron ore of great economic value occur in many sedimentary rocks, such as the lias, oolites and lower greensand of various parts of england. they appear in some cases to be altered limestones and in others altered glauconitic sandstones. an oolitic structure is sometimes present, and the ores are generally phosphatic, and may contain perhaps 30% of iron. the oolitic brown ores of lorraine and luxemburg are known as "minette," a diminutive of the french _mine_ (ore), in allusion to their low content of metal. granular and concretionary limonite accumulates by organic action on the floor of certain lakes in sweden, forming the curious "lake ore." larger concretions formed under other conditions are known as "bean ore." limonite often forms a cementing medium in ferruginous sands and gravels, forming "pan"; and in like manner it is the agglutinating agent in many conglomerates, like the south african "banket," where it is auriferous. in iron-shot sands the limonite may form hollow concretions, known in some cases as "boxes." the "eagle stones" of older writers were generally concretions of this kind, containing some substance, like sand, which rattled when the hollow nodule was shaken. bog iron ore is an impure limonite, usually formed by the influence of micro-organisms, and containing silica, phosphoric acid and organic matter, sometimes with manganese. the various kinds of brown and yellow ochre are mixtures of limonite with clay and other impurities; whilst in umber much manganese oxide is present. argillaceous brown iron ore is often known in germany as _thoneisenstein_; but the corresponding term in english (clay iron stone) is applied to nodular forms of impure chalybite. j. c. ullmann's name of stilpnosiderite, from the greek [greek: stilpnos] (shining) is sometimes applied to such kinds of limonite as have a pitchy lustre. deposits of limonite in cavities may have a rounded surface or even a stalactitic form, and may present a brilliant lustre, of blackish colour, forming what is called in germany _glaskopf_ (glass head). it often happens that analyses of brown iron ores reveal a larger proportion of water than required by the typical formula of limonite, and hence new species have been recognized. thus the yellowish brown ore called by e. schmidt xanthosiderite, from [greek: zanthos] (yellow) and [greek: sideros] (iron), contains fe2o(oh)4, or fe2o3·2h2o; whilst the bog ore known as limnite, from [greek: limne] (marsh) has the formula fe(oh)3, or fe2o3·3h2o. on the other hand there are certain forms of ferric hydrate containing less water than limonite and approaching to haematite in their red colour and streak: such is the mineral which was called hydrohaematite by a. breithaupt, and is now generally known under r. hermann's name of turgite, from the mines of turginsk, near bogoslovsk in the ural mountains. this has the formula fe4o5(oh)2, or 2fe2o3·h2o. it probably represents the partial dehydration of limonite, and by further loss of water may pass into haematite or red iron ore. when limonite is dehydrated and deoxidized in the presence of carbonic acid, it may give rise to chalybite. limousin (or limosin), leonard (c. 1505-c. 1577), french painter, the most famous of a family of seven limoges enamel painters, was the son of a limoges innkeeper. he is supposed to have studied under nardon penicaud. he was certainly at the beginning of his career influenced by the german school--indeed, his earliest authenticated work, signed l. l. and dated 1532, is a series of eighteen plaques of the "passion of the lord," after albrecht durer, but this influence was counter-balanced by that of the italian masters of the school of fontainebleau, primaticcio, rosso, giulio romano and solario, from whom he acquired his taste for arabesque ornament and for mythological subjects. nevertheless the french tradition was sufficiently ingrained in him to save him from becoming an imitator and from losing his personal style. in 1530 he entered the service of francis i. as painter and _varlet de chambre_, a position which he retained under henry ii. for both these monarchs he executed many portraits in enamel--among them quite a number of plaques depicting diane de poitiers in various characters,--plates, vases, ewers, and cups, besides decorative works for the royal palaces, for, though he is best known as an enameller distinguished for rich colour, and for graceful designs in grisaille on black or bright blue backgrounds, he also enjoyed a great reputation as an oil-painter. his last signed works bear the date 1574, but the date of his death is uncertain, though it could not have been later than the beginning of 1577. it is on record that he executed close upon two thousand enamels. he is best represented at the louvre, which owns his two famous votive tablets for the sainte chapelle, each consisting of twenty-three plaques, signed l. l. and dated 1553; "la chasse," depicting henry ii. on a white horse, diane de poitiers behind him on horseback; and many portraits, including the kings by whom he was employed, marguerite de valois, the duc de guise, and the cardinal de lorraine. other representative examples are at the cluny and limoges museums. in england some magnificent examples of his work are to be found at the victoria and albert museum, the british museum, and the wallace collection. in the collection of signor rocchi, in rome, is an exceptionally interesting plaque representing frances i. consulting a fortune-teller. see _leonard limousin: peintre de portraits_ (_l'oeuvre des peintres emailleurs_), by l. boudery and e. lachenaud (paris, 1897)--a careful study, with an elaborate catalogue of the known existing examples of the artist's work. the book deals almost exclusively with the portraits illustrated. see also alleaume and duplessis, _les douze apotres--emaux de leonard limousin_, &c. (paris, 1865); l. boudery, _exposition retrospective de limoges en 1886_ (limoges, 1886); l. boudery, _leonard limousin et son oeuvre_ (limoges, 1895); _limoges et le limousin_ (limoges, 1865); a. meyer, _l'art de l'email de limoges, ancien et moderne_ (paris, 1896); emile molinier, _l'emaillerie_ (paris, 1891). limousin (lat. _pagus lemovicinus, ager lemovicensis, regio lemovicum, lemozinum, limosinium_, &c.), a former province of france. in the time of julius caesar the _pagus lemovicinus_ covered the county now comprised in the departments of haute-vienne, correze and creuse, with the _arrondissements_ of confolens in charente and nontron in dordogne. these limits it retained until the 10th century, and they survived in those of the diocese of limoges (except a small part cut off in 1317 to form that of tulle) until 1790. the break-up into great fiefs in the 10th century, however, tended rapidly to disintegrate the province, until at the close of the 12th century limousin embraced only the viscounties of limoges, turenne and comborn, with a few ecclesiastical lordships, corresponding roughly to the present _arrondissements_ of limoges and saint yrien in haute-vienne and part of the _arrondissements_ of brive, tulle and ussel in correze. in the 17th century limousin, thus constituted, had become no more than a small _gouvernement_. limousin takes its name from the _lemovices_, a gallic tribe whose county was included by augustus in the province of _aquitania magna_. politically its history has little of separate interest; it shared in general the vicissitudes of aquitaine, whose dukes from 918 onwards were its over-lords at least till 1264, after which it was sometimes under them, sometimes under the counts of poitiers, until the french kings succeeded in asserting their direct over-lordship. it was, however, until the 14th century, the centre of a civilization of which the enamelling industry (see enamel) was only one expression. the limousin dialect, now a mere _patois_, was regarded by the troubadours as the purest form of provencal. see a. leroeux, _geographie et histoire du limousin_ (limoges, 1892). detailed bibliography in chevalier, _repertoire des sources. topo-bibliogr._ (montbeliard, 1902), t. ii. s.v.